AN APPARATUS AND A METHOD FOR MANUFACTURING OF A TEXTURED YARN

Abstract

 The invention provides for a gas-dynamic yarn texturing expansion chamber, a texturing apparatus equipped with the gas-dynamic yarn texturing expansion chamber, a textured yarn, a method for yarn texturing, an artificial turf, a method and a system of manufacturing of the artificial turf. The gas-dynamic yarn texturing expansion chamber comprises: an inlet for a fluid flow and a yarn flow; at least a section having a sidewall being porous to provide egress of a portion of the fluid flow from the expansion chamber; and a downstream outlet for the yarn flow and another portion of the fluid flow.

Description

Field of the invention

[0001] This invention relates to a method and an apparatus for yarn texturing, and more particularly to an expansion chamber of the apparatus. The yarn can be but is not limited to a textured yarn for textile or artificial turf manufacturing. The invention further relates to an artificial turf with textured yarn, a system and a production method for manufacturing of the artificial turf.

Background and related art

[0002] Artificial turf or artificial grass is a material that is made up of textured fibers used to replace natural grass. The structure of the artificial turf is designed such that the artificial turf has an appearance which resembles natural grass. Typically artificial turf is used as a surface for sports such as soccer, American football, rugby, tennis, golf, and for playing fields or exercise fields. Furthermore, artificial turf is frequently used for landscaping applications.

[0003] Artificial turf may be manufactured using techniques for manufacturing carpets. For example, artificial turf fibers which have the appearance of grass blades may be tufted or attached to a backing. Artificial turf does not need to be irrigated or trimmed and has many other advantages regarding maintenance effort and other aspects. Irrigation can be difficult due to regional restrictions for water usage. In other climatic zones the re-growing of grass and re-formation of a closed grass cover is slow compared to the damaging of the natural grass surface by playing and/or exercising on the field. Artificial turf does not need sunlight and thus can be used in places where there is not enough sunlight to grow natural grass. To ensure that artificial turf replicates the playing qualities of good quality natural grass, artificial turf needs to be made of materials that will not increase the risk of injury to players and that are of adequate durability. Many sports fields are subjected to high-intensity use relating to player-to-surface interactions and ball-to-surface interactions. The surface of the artificial turf fibers must be smooth enough to prevent injuries to the skin of the players when sliding on the surface, but at the same time must be sufficiently embedded into the substructure to prevent the fibers from coming loose. Thus, the materials used for producing artificial turf must have highly specific properties regarding smoothness, brittleness, resistance to shear forces, etc.

[0004] The gas-dynamic texturizing process employing heated compressed gas is often used for manufacturing of texturized filaments. This process is also called bulked continuous filament texturizing (Chapter 4.12.6 "BCF (Bulked Continuous Filament) Texturizing in "Synthetic Fibers" by Franz Fourne, Carl Hanser Verlag GmbH & Co, 1999, ISBN 10: 3446160728/ISBN 13: 9783446160729, pp. 456-460).

[0005] The patents EP 0 282 815 B1 and EP 0 163 039 B1 disclose a texturing apparatus for gas-dynamic texturizing of endless filament threads.

Summary

[0006] The following definitions are provided to determine how terms used in this application, and in particular, how the claims, are to be construed. The organization of the definitions is for convenience only and is not intended to limit any of the definitions to any particular category.

[0007] A "polymer blend," as understood herein, is a mixture of polymers, which can have different types (e.g., different types of the same polymer, such as different types of polyethylene), at least two different miscible polymers, at least two different immiscible polymers and at least one compatibilizer, which can be another polymer or another compound, or a combination thereof. The polymer blend can comprise various additives added to the polymer mixture. The polymer blend can be at least a two or three-phase system. A three-phase system as used herein encompasses a mixture that separates out into at least three distinct phases. The polymer blend can comprise a first polymer, a second polymer, and a compatibilizer. These three items form the phases of the three-phase system. If there are additional polymers or compatibilizers added to the system then the three-phase system may be increased to a four, five, or more phase system. The first polymer and the second polymer are immiscible. The first polymer forms polymer beads surrounded by the compatibilizer within the second polymer.

[0008] The term "polymer blend," as understood herein, encompasses the term "polymer mixture". The term "blend," as understood herein, encompasses both a physical mixture of polymer particles on a macroscopic scale and a dispersion of polymers on a molecular scale.

[0009] The terms "polymer bead" and "beads" may refer to a localized region, such as a droplet, of a polymer that is immiscible in the second polymer. The polymer beads may in some instances be round or spherical or oval-shaped, but they may also be irregularly shaped. In some instances the polymer bead will typically have a size of approximately 0.1 to 3 micrometers, preferably 1 to 2 micrometers in diameter. In other examples, the polymer beads will be larger. They may, for instance, have a diameter up to 50 micrometers.

[0010] A polymer blend may also be composed of compatible and miscible polymeric components. Compatibility means, as understood herein, that blending of, e.g., two distinct polymers, leads to an enhancement of at least one desired property, when comparing the blend to one of the two individual blend components. Ideally, the performance of the blend lies in between the range, which is flanked by the two blend components, in fact, in strong relationship to the concentration ratio. However, compatibility is only given in some exceptional cases, mostly related to completely amorphous polymers. In nearly all other polymer mixtures, an enhancement of properties fails and the resulting blend stays far behind the property profile of the individual blend components. Polymer miscibility, as used here, is meant in a thermodynamic sense and can be compared to solubility. Completely miscible polymers form a single phase continuity upon mixing, i.e., one component is fully dispersed in the other component. This is in most cases true for amorphous polymers, but it is a rare case for semi-crystalline polymers. Complete miscibility would also require co-crystallization of the crystalline phase. This explicitly would affect the melting behavior of polymeric blends.

[0011] The term "polymorphism" or "polymorphic modification," as used herein, refers to the fact that solid matter is able to exist in different forms of crystal structures. This may include not only different crystallographic unit cells but different crystal imperfections as well. The polymer blend can be composed of two different polymorphic modifications of the same polymer.

[0012] The "melting temperature" is, as understood here, a characteristic temperature of a polymer blend, at which at least a portion of a crystalline fraction of one of the polymers of the polymer blend melts. In the case when a crystalline fraction of the polymer of the polymer blend has polymorphism, then the polymorphic modification of the polymer having polymorphism has a respective melting temperature at which at least a portion of the polymorphic modification is molten. Melting at the melting temperature is a process wherein the thermal energy in a crystalline fraction of a polymer is sufficient to overcome the intermolecular forces of attraction in the crystalline lattice so that the lattice breaks down and at least a portion of the crystalline fraction becomes a liquid, i.e., it melts. Further in the text, the term "melting temperature" of a polymer refers to a melting process of its crystalline fraction without explicit reference to the latter. This formulation is in conformity with the general practice, because purely crystalline polymers are very rarely used and are quite difficult, if not impossible, to produce.

[0013] The terms "filament" and "monofilament" encompass an elongated member of a polymeric material having its length many orders of magnitude bigger than its width and thickness

[0014] The terms "yarn" and "artificial turf yarn" encompass a monofilament or a bundle of loose monofilaments.

[0015] The term "fiber" encompasses a short elongated member of polymeric, ceramic, or metallic material, for instance a fragment of a filament.

[0016] The term "texturing" encompasses a process causing irregular shape of individual constituents of a yarn. The irregular shape can be but is not limited to: a kinked shape, a curled shape, a bended shape, a twisted shape.

[0017] The term "gas-dynamic" texturing encompasses a process causing irregular shape of individual constituents of a yarn by exerting forces on different individual constituents caused by a compressed fluid (e.g. air) injected into an expansion chamber (e.g. diffuser). The irregular shape can be but is not limited to: a kinked shape, a curled shape, a bended shape, a twisted shape.

[0018] The terms "textured yarn" and "textured artificial turf yarn" encompass a textured monofilament or a bundle of loose textured monofilaments.

[0019] The term "degree of texturing" (α) is, as understood herein, a ratio of a first length (L1) and a second length (L2) of a yarn monofilament fragment, wherein L1 is a length of the vertically hanged yarn monofilament fragment when a first predefined tensile force (F1), e.g. 1 N, is applied to the monofilament yarn fragment, L2 is a length of the vertically hanged monofilament yarn fragment when a second tensile force (F2), e.g. 2 N, is applied to the yarn monofilament fragment, and F1<F2. The length of the yarn monofilament fragment can be selected such that it has a length of 1 m when the first tensile force is applied. The degree of texturing can be expressed as follows α=L2/L1. This parameter can be used as a measure of comparison of the degree of texturing of different monofilament yarn fragments. One monofilament yarn fragment has a higher degree of texturing than the other one when the monofilament yarn fragment has a higher value of the parameter α than the other one, on condition that both of the monofilament yarn fragments have the same length, when the first tensile force is applied. Evaluation of the degree of texturing can be used as a measure of variation of the degree of texturing when different fragments of the monofilament yarn have different degree of texturing. The different fragments can be, for instance, the fragments of textured yarn produced at different time intervals within the texturing process using the same yarn. In this case, the variation of the degree of texturing can indicate a stability of performance of the texturing apparatus. Bundles of monofilament yarn fragments can be used instead of a single monofilament yarn fragment in order to determine an average value of the degree of texturing. Alternatively, an average of several second lengths, each evaluated for a respective fragment having the same first length, can be used for determination of the average value of degree of texturing.

[0020] The term "crimp characteristic" is, as understood herein, a number of twists and kinks along a textured monofilament per unit length. A twist means an at least half lengthwise rotation of a filament and a kink means an at least 90 degrees deflection from the longitudinal direction of the filament.

[0021] The term "expansion chamber" of the texturing apparatus for gas-dynamic texturing of yarn encompasses the term "diffuser" of the texturing apparatus. The expansion chamber is configured to cause a turbulent flow of a fluid, when it is injected under pressure into an inlet of the expansion chamber via an opening having a diameter smaller than a diameter of an opening of the inlet of the expansion chamber. Such a turbulent flow causes texturing of a yarn being injected into the expansion chamber, e.g. via the inlet of the expansion chamber.

[0022] The term "porous" means, as understood herein, that a porous component, e.g., a side wall of the expansion chamber is permeable for a fluid, e.g., air. A porosity (ε) of the component is determined as 100% multiplied by a ratio of a difference of a volume (Vc) of the component and a volume (Vp) of pores of the component and the volume of the component. In other words, the porosity of the component is determined by the following equation: ε = (Vc-Vp) / Vc * 100%. The volume of pores can be determined by a volume of a liquid required to fill the pores of the component.

[0023] The fluid permeability of a porous component (e.g. a porous sidewall of the expansion chamber) can be characterized by a viscous permeability coefficient and/or inertia permeability coefficient determined according to the "Determination of fluid permeability" standard ISO 4022:2018 formulated by the International Organization for Standardization. A porous material has a higher fluid permeability than another porous material, when a viscous permeability coefficient of the porous material is bigger than a viscous permeability coefficient of the other porous material and/or an inertia permeability coefficient of the porous material is bigger than an inertia permeability coefficient of the other porous material.

[0024] A porous component has a homogenous fluid permeability, when at least one of the following criteria is complied with:

a) a viscous permeability coefficient of the porous component varies less than 10% (preferably less than 5%) over a surface of the porous component;

b) an inertia permeability coefficient of the porous component varies less than 10% (preferably less than 5%) over the surface of the porous component;

c) a local fluid flow through the porous component for a predefined pressure difference between an interior and an exterior of the porous component varies less than 10% (preferably less than 5%) over the surface of the porous component.

[0025] A term yarn inlet port of a texturing apparatus encompasses herein an injector jet and an inlet port for receiving the yarn and guiding it into a yarn channel of the texturing apparatus.

[0026] Utilization of textured yarns in artificial turf carpets may provide for the above-mentioned required properties of the artificial turf carpets. Textured yarns are different from flat monofilament yarns in that they are irregularly crimped. The textured yarns exhibit a zig-zag shape having at least one of the characteristic features such as kinks, jogs, bends, crinkles, buckling, and curls. These features make the textured yarns more voluminous and soft when manufactured into artificial turf, compared to flat monofilament fibers. The textured yarn may also be advantageous over flat yarn concerning the capability of holding infill material in its place, i. e. reducing the splash of infill material when, e. g. a ball hits the ground.

[0027] The invention provides for a texturing apparatus for gas-dynamic texturing of yarn, an expansion chamber for the texturing apparatus, a method for texturing of a yarn, system and a method for manufacturing of an artificial turf, as formulated in the independent claims. Embodiments are given in the dependent claims.

[0028] The system for manufacturing of textured artificial tuft yarn is configured to perform the gas-dynamic texturizing process employing heated compressed fluid (air). This process is also called bulked continuous filament (BCF) texturizing. The BCF process produces good textured effect and matches the spinning speed of reel-to-reel yarn manufacturing (100-1000 m/min).

[0029] In one aspect the invention provides for a gas-dynamic yarn texturing expansion chamber. The expansion chamber comprises: an inlet for a fluid flow and a yarn flow; at least a section having a sidewall being porous to provide egress of a portion of the fluid flow from the expansion chamber; and an outlet (i.e. downstream outlet) for the yarn flow and another portion of the fluid flow.

[0030] In another aspect the invention provides for an apparatus for a gas-dynamic texturing of a yarn, e.g. artificial turf yarn and/or monofilament yarn. The apparatus comprises: a fluid inlet for a fluid under pressure for gas-dynamic texturing of the artificial turf yarn in the texturing apparatus, a yarn channel having a yarn inlet, the fluid inlet being fluidly coupled to the yarn inlet; and the aforementioned gas-dynamic yarn texturing expansion chamber leading out of the yarn channel downstream thereof.

[0031] Utilization of the porous sidewall may provide more homogenous fluid egress through the sidewall and/or more homogeneous gas-dynamic properties of a fluid flow in the expansion chamber, i.e. more stable texturing process. In turn, the improved fluid flow may result in improved properties of the textured yarn such as, degree of texturing and/or crimp characteristics, in particular in reduced variation of the textured yarn properties over a length of the textured yarn. Utilization of the textured filament yarn having the improved properties may further result in improved properties of products manufactured using the textured yarn, such as for instance textile and artificial turf. In particular, the artificial turf may have better mechanical and/or coloring properties and/or durability. For instance, when the textured yarn having high variation of properties over its length is used for manufacturing of the artificial turf, a pile height of individual tufting tracks may vary, depending on the properties of the individual textured filament yarn corresponding to an individual tufting needle. As a result, the artificial turf may show unwanted streaks, i. e. rows of fibers protruding from areas, which in turn may cause unwanted variation of mechanical and/or coloring properties and/or durability of the artificial turf.

[0032] Utilization of the porous sidewall may have further advantages. The texturing apparatus equipped with the expansion chamber having the porous sidewall provides a higher level of work safety, because it produces less noise in comparison with conventional texturing apparatuses, which may produce noise of 90 - 100 dB. Such a high level of noise makes ear protection imperative for operators of the texturing process. The porous sidewall may act as a filter which traps abrasion particles generated in the texturing process. As a result thereof an environment around the texturing apparatus is kept more clean. An inner surface of the porous sidewall is rough due to its porosity. The porosity may be advantageous because the rough inner surface of the expansion chamber may facilitate deceleration of the yarn in the expansion chamber and as a result thereof building of a yarn plug in the expansion chamber.

[0033] In another embodiment, the gas-dynamic yarn texturing expansion chamber is a porous sinter part made of: metal granules; metal fibers; ceramic granules; and/or a mixture of metal granules and metal fibers. The porosity may be more than 15% (preferably more than 25 % and more preferably more than 35%) and/or less than 60% (preferably less than 55% and more preferably less than 50%) when the sinter part is made of sintered metal granules. The porosity may be more than 45% (more preferably more than 50% and more preferably more than 55%) and/or less than 90% (less than 85% and more preferably less than 80%) when the sinter part is made of sintered metal fibers.

[0034] This embodiment may be advantageous, because the sintering may provide for a desired mechanical stability and fluid permeability of the expansion chamber. For instance, the inlet of the expansion chamber can be formed by sintered granules and/or fibers that provide higher degree of hardness of the inlet than of the section having the porous sidewall, wherein the inlet being configured for forming a frictional or non-positive connection (e.g. spigot-socket connection). In particular, a material of the inlet constituted by said sintered granules and/or fibers may have a higher shear strength than a material of said section. When necessary, a particular section such as the inlet may be made solid. In addition, the sintering may provide for different fluid permeability of different sections of the expansion chamber.

[0035] Such a diversity of properties of different sections of the expansion chamber may be achieved by using granules and/or fibers having different grades for manufacturing different portions of the expansion chamber. The sintering of the granules and/or fibers of different grades may be made in one sintering process by filling different portions of a mold used for the sintering process with granules and/or fibers of different grades. The grade of granules may be characterized by at least one of the following parameters: a minimum granule weight, a maximum granule weight, an average granule weight, a minimum characteristic size, a maximum characteristic size, and an average characteristic size. In case when granules are spherical, the characteristic size can be a diameter of a granule. The grade of fibers may be characterized by at least one of the following parameters: a minimum fiber weight, a maximum fiber weight, an average fiber weight, a minimum characteristic size, a maximum characteristic size, and an average characteristic size. The characteristic size can be a length of a fiber and/or an area of its cross-section.

[0036] In case when the sinter part is made of metal granules, then the section having the porous sidewall may be made of metal granules having an average weight being bigger than an average weight of metal granules out of which the inlet is made.

[0037] In case when the sinter part is made of metal fibers, then the section having the porous sidewall may be made of metal fibers having an average weight being bigger than an average weight of metal fibers out of which the inlet is made.

[0038] In case when the sinter part is made of ceramic granules, then the section having the porous sidewall may be made of ceramic granules having an average weight being bigger than an average weight of ceramic granules out of which the inlet is made.

[0039] In case when the sinter part is made of a mixture of metal granules and metal fibers, then an average weight of metal granules of a mixture out which the section having the porous sidewall is made may be bigger than an average weight of metal granules of a mixture out of which the inlet is made and/or an average weight of metal fibers of the mixture out which the section having the porous sidewall is made may be bigger than an average weight of metal fibers of the mixture out of which the inlet is made.

[0040] The porous sidewall of the expansion chamber may have at least one the following pore size distribution characteristics determined according to the ASTM E1294-89(1999) "Standard Test Method for Pore Size Characteristics of Membrane Filters Using Automated Liquid Porosimeter" formulated by the ASTM International, formerly known as American Society for Testing and Materials. The smallest pore diameter is bigger than 10 µm, preferably bigger than 25 µm, more preferably bigger than 50 µm. The effective pore diameter, MFP, is bigger than 25 µm, preferably bigger than 50 µm. The effective pore diameter is less than 200 µm, preferably less than 150 µm. The biggest pore diameter is less than 500 µm, preferably less than 400 µm, more preferably less than 300 µm.

[0041] A material of the porous sidewall may have at least one of the following characteristics. A viscous permeability coefficient is bigger than 10^-12 m², preferably bigger than 50*10^-12 m², more preferably bigger than 10^-11 m². The viscous permeability coefficient is less than 5*10^-10 m², preferably less than 2.5*10^-10 m², more preferably less than 10^-10 m². An inertia permeability coefficient is bigger than 10^-6 m, preferably bigger than 5*10^-6 m, more preferably bigger than 10^-5 m. The inertia permeability coefficient is less than 10^-4 m, preferably less than 3*10^-4 m, more preferably less than 6*10^-4 m.

[0042] According to a measurement procedure of ISO 4022:2018 a disk sample having a thickness of 3 mm and a diameter of 48.4 cm², which is made of the material of the porous sidewall, provides for an air flow of air having temperature of 0 degrees Centigrade at a pressure drop of 10⁵ Pa. The air flow rate can be more than 30 m³/h*m², preferably bigger than 50 m³/h*m², more preferably more than 70 m³/h*m². The air flow rate can be less than 200 m³/h*m², preferably less than 170 m³/h*m², more preferably less than 140 m³/h*m².

[0043] The granules and fibers may be made using the following non-limiting list of metals and metal alloys: bronze (e.g. bronze with 90% copper content by weight), monel, inconel, inox B (AISI 304L), inox C (AISI 316L), nickel, and steel (e.g. stainless steel). The granules and fibers may be made using the following non-limiting list of ceramic materials: oxides, nitrides and carbides of group 2 elements (e.g. Mg), group 4 elements (e.g. Zr), group 6 elements (e.g. W), group 13 elements (e.g. Al) and group 14 elements of the periodic table of elements (e.g. Si) and combinations thereof.

[0044] In another embodiment, the porous sidewall of the section of expansion chamber may have a tubular form and a homogeneous fluid permeability.

[0045] In another embodiment, the section having the porous sidewall is made of one of: metal foam, ceramic foam, and porous plastics.

[0046] This embodiment may be advantageous, because it may provide for structural stability of the expansion chamber in combination with a low heat conductivity and/or high roughness of an inner surface the side wall. The latter may be or particular advantage for creation of a turbulent fluid flow in the expansion chamber. The porous metal foam layer can be made using the following non-limiting list of metals and metal alloys: bronze, aluminum, and steel. The porous ceramic foam layer can be made using the following non-limiting list of ceramic materials: aluminum oxide, silicon carbide, zirconium oxide, and hafnium oxide. The porous plastic layer can be made using the following non-limiting list of plastics: glass-fiber reinforced plastics, polyethylene, polyether ether ketone (PEEK), poly ether ketone (PEK), and polyphenylene sulfide (PPS). The metal foam may have a porosity of more than 85% and less than 95%. The ceramic foam may have a porosity of more than 85% and less than 95%.

[0047] In another embodiment, the gas-dynamic yarn texturing expansion chamber comprises an inner channel connecting an outlet opening of the downstream outlet and an inlet opening of the inlet, wherein the expansion chamber has at least one of the following characteristics a) - i):

a) The inner channel has a tapering in a direction from the downstream outlet to the inlet, i.e. its diameter increases in a direction from the inlet to the downstream outlet. Alternatively, the inner channel can have a constant diameter.

b) An air permeability and/or porosity of the sidewall increases in a direction from the inlet to the downstream outlet. The increase in the air permeability may be achieved by a decrease in a sidewall thickness in the same direction and/or using different materials having different porosities for different portions of the side wall. For instance a section of the sidewall positioned closer to the downstream outlet than another section of the sidewall may be made of a material having higher porosity than a material of the other section of the sidewall.

c) A length of the inner channel is at least 8 times, preferably at least 12 times, more preferably at least 14 times, bigger than a diameter of the inlet opening.

d) When the inner channel has the increasing diameter, a diameter of the outlet opening is at least 1.2 times, more preferably at least 1.3 times, bigger than the diameter of the inlet opening.

e) The sidewall comprises a first tubular layer and a second tubular layer circumventing the first tubular layer and the first tubular layer has a higher air permeability and/or porosity than the second tubular layer.

f) The gas-dynamic yarn texturing expansion chamber is configured to perform the following when a fluid under pressure is injected into the inlet via an opening (e.g. an opening of the yarn channel) having a diameter less than the diameter of the inlet opening: operate as a diffuser for the fluid flow, and/or cause generation of a vortex fluid flow adjacent to a surface of the inner channel, wherein a thickness of the vortex fluid flow decreases in a direction from the inlet to the downstream outlet.

g) A ratio of a diameter of the opening of the outlet of the yarn channel and a diameter of an opening of inlet of the expansion chamber are in the range of 0.5 - 0.7.

h) A length of the inner channel is bigger than 0.05 m and/or less than 0.071 m.

i) The diameter of the opening of the inlet is bigger than 0.005 m and/or less than 0.007 m.

[0048] This embodiment may be advantageous because it may provide for optimal, in particular stable, gas-dynamic properties of the fluid flow in the expansion chamber.

[0049] In another embodiment, the porous sidewall of the gas-dynamic yarn texturing expansion chamber comprises a first tubular layer made of a first porous material and a second tubular layer made of a second porous material, wherein the first porous material has a higher air permeability and/or porosity than the second porous material and the second tubular layer circumvents the first tubular layer. Both of the first and the second tubular layers may have the same heights (i.e. heights of geometrical hollow cylinder shapes constituted by these layers).

[0050] This embodiment may be advantageous, because it may provide a combination of a roughness of an inner surface of the porous sidewall and a permeability of the porous sidewall which may be difficult to achieve using one material for making the porous sidewall. As a result, such a porous side wall may provide for an advanced stability of properties of the fluid flow inside the expansion chamber and as a result thereof more uniform properties of the textured yarn.

[0051] In another embodiment, the texturing apparatus comprises a housing and a release mechanism for detaching the inlet of the expansion chamber from the housing. The yarn channel is arranged within the housing.

[0052] This embodiment may be advantageous, because the release mechanism may provide for a fast exchange of the expansion chamber, which may have its pores clogged by debris generated by the texturing process.

[0053] In another embodiment, the texturing apparatus comprises a heating device being configured to heat the texturing apparatus (in particular one or more components of the texturing apparatus such as the expansion chamber, the yarn channel, a housing of the texturing apparatus, and a yarn inlet port by electromagnetic induction or through physical contact with the texturing apparatus (in particular with the one or more of said respective components). The heating device configured to heat the texturing apparatus through physical contact can be an electrical resistance heater. Electromagnetic induction heating can heat one or more electrically conducting components of the texturing apparatus by electromagnetic induction, through heat generated in the one or more components by eddy currents. A heating device configured to heat one or more components of the texturing apparatus by electromagnetic induction can comprise an electromagnet and an electronic oscillator that passes a high-frequency alternating current (AC) through the electromagnet. The rapidly alternating magnetic field penetrates the one or more components of the texturing apparatus, generating electric currents (eddy currents) inside the one or more electrically conducting components. The eddy currents flowing through the resistance of the material heat it by Joule heating. In ferromagnetic (and ferrimagnetic) materials like iron, heat may also be generated by magnetic hysteresis losses.

[0054] More specifically, the texturing apparatus may comprise one or more heating devices, each being configured to heat a respective component of the texturing apparatus by electromagnetic induction or through physical contact with said respective component. The components can be but are not limited to: the expansion chamber, the yarn channel, the housing, and the yarn inlet port. Heating of one of the components may cause heating of the other components which are thermally coupled to the heated component. The yarn channel is arranged within the housing and thermally coupled thereto. The expansion chamber may be thermally coupled to the housing and/or arranged partially within the housing or adjacent to it. The expansion chamber may be further thermally coupled to the yarn channel. The thermal coupling may be provided by a connection of the expansion chamber to the housing and/or the yarn channel. In addition this connection is configured to function as the release mechanism providing attachment/detachment of the expansion chamber to the texturing apparatus. The connection can be but is not limited to: a spigot-socket fitting connection, a non-positive (fitting) connection, a frictional connection, a clamping connection. The yarn inlet port and the expansion chamber are arranged at opposite ends of the yarn channel and/or the housing circumventing the yarn channel. The yarn inlet port may be thermally coupled and/or affixed to the housing. The heating device configured to heat the component of the texturing apparatus through physical contact can be affixed to said component such that the heating device is in direct physical contact with said component. A medium (e.g. heat-conducting paste) can be used in between said component and the heating device in order to facilitate heat transfer between said component and the heating device.

[0055] Such a configuration of the texturing apparatus and/or expansion chamber can provide the following advantages. First, it can be more energy efficient in comparison with a texturing apparatus in which the texturing apparatus is heated only by a hot fluid. One or more heating devices can ramp-up the temperature of the texturing apparatus, in particular the expansion chamber, from ambient temperature (or any temperature below a temperature required for the texturing process) to the temperature required for the texturing process much faster in comparison with the case when only hot fluid (e.g. hot air) provides the heating of the texturing apparatus. As a result thereof idle time of the texturing system is reduced. This functionality may be of particular advantage, for the procedure of exchanging the expansion chamber. A detachable heating device may be attached to a newly mounted expansion chamber for ramping its temperature from ambient temperature to a process temperature of the expansion chamber. Second, the texturing apparatus equipped with one or more heating devices may provide for an advanced process control. When the aforementioned heating device or devices are not used the fluid parameters such as flow and temperature have to be tuned such that the texturing apparatus has the desired process temperature and the flow of the fluid in the texturing apparatus (e.g. in a yarn channel of the texturing apparatus and/or in an expansion chamber of the texturing apparatus) has optimal gas-dynamic properties for the texturing process. This is not the case when one or more heating devices for heating the texturing apparatus are employed. In this case the heating of the texturing apparatus is primarily provided by the one or more heating devices, whereas the flow of the fluid can be tuned primarily (or only) for the purpose of achieving optimal gas-dynamic properties of the fluid flow in the texturing apparatus. Third, the consumption of the fluid may be less when one or more apparatus heating devices are used. In this case the hot fluid is used primarily for generating the fluid flow in the texturing apparatus, i.e. there is no need to provide high flow of the hot fluid in order to heat the texturing apparatus. Fourth, when one or more of the heating devices are configured such that they heat the critical components e.g. yarn channel and/or expansion chamber, the temperature of these components may be controlled in a more precise way. The heating device configured to heat the housing may have another advantage. In this case the heating device can be mounted on (or arranged around) an external surface of the housing. Such a configuration of the heating device does not compromise any design considerations for internal components of the texturing apparatus.

[0056] In another embodiment, the texturing apparatus comprises a first temperature sensor configured to sense a temperature of the texturing apparatus and a first controller coupled to the first temperature sensor, wherein the first controller is configured to control the heating device such that the temperature of at least a portion the texturing apparatus (e.g. yarn channel) is held at a desired temperature. When the texturing apparatus comprises several heating devices, then each of them may have a respective first temperature sensor for sensing its temperature, so that the first controller can operate each of the heating devices independently to hold the respective component at the desired temperature. In particular, the expansion chamber may comprise a first temperature sensor and a heating device for heating the expansion chamber, wherein the heating device and the temperature sensor are configured such, that they can be detached from one expansion chamber and attached to another one.

[0057] The texturing apparatus may further comprise: a fluid heating device for heating the fluid; a second temperature sensor configured to sense a temperature of the fluid; and a second controller coupled to the second temperature sensor, wherein the second controller is configured to control the fluid heating device such that the temperature of the fluid is held at the desired temperature of the fluid. The second temperature sensor may be positioned in a channel for guiding the fluid into the yarn channel, wherein said channel is constituted by an inner wall of the housing and an outer wall of a conduit of the yarn channel. Such a positioning of the second temperature sensor may be advantageous because the second temperature sensor is closely positioned to an inlet of the yarn channel. Thus a very accurate temperature control of the fluid used for the texturing process is provided, because eventual changes in the fluid temperature in a fluid distribution system (e.g. gas pipe lines) and/or in the texturing apparatus can be effectively compensated. Alternatively, the second temperature sensor may be positioned in an inlet pipe of the fluid inlet of the texturing apparatus. Such a positioning of the second temperature sensor may have its own advantages as well. For instance, the positioning of the second temperature sensor in the inlet pipe may not compromise any other design considerations of the texturing apparatus.

[0058] The desired temperature depends on the type of polymer or polymer blend used for the manufacturing of the textured yarn. The desired temperature may be in the range of 50 - 150 degrees Celsius, preferably in the range 70 - 130 degrees Celsius, more preferably in the range of 90 - 110 degrees Celsius. The range of 90 - 110 degrees Celsius may be optimal for a polymer blend prepared comprising linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE). The range of 90-100 degrees Celsius may be optimal for a polymer blend comprising Polyamide and Polyethylene.

[0059] This embodiment can be advantageous, because it may provide an effective temperature control/stability of the texturing apparatus, in particular the expansion chamber. In addition, utilization of several independently operated first heating devices may provide a more precise control of the components of texturing apparatus and thereby reduce variation in properties of the textured yarn such as degree of texturing and crimp characteristics over the length of the textured yarn.

[0060] In another embodiment, the yarn comprises a polymer blend of polymers, wherein the desired temperature is determined using differential scanning calorimetry (DSC) data of a sample of the polymer blend. The desired temperature, is the temperature required for the texturing process in the texturing apparatus. In particular, this can be the desired temperature of the yarn channel and/or the fluid in texturing apparatus. Further information related to the determination of the desired temperature is disclosed in the European patent application EP17195136.1.

[0061] Utilization of the DSC data may be advantageous, because it may provide for a melting temperature of the polymer (or its particular polymorphic modification) in the polymer blend. As discussed further in greater detail, the texturing of the monofilament yarn may be performed within the temperature range, in which at least a portion of a crystalline fraction (or of a polymorphic modification) of at least one of the polymers of the polymer blend remains in a solid state. Thus the knowledge of the melting temperatures determined using DSC data may provide for the temperature range that may be optimal for the texturing process.

[0062] In another embodiment the yarn comprises a blend of polymers. The desired temperature is determined such that a portion of a crystalline fraction of the polymer blend is in a solid state when the gas-dynamic texturing is performed and another portion of the crystalline fraction of the polymer blend is in a molten state when the gas-dynamic texturing is performed.

[0063] This embodiment may be advantageous because it may provide for an optimal process temperature, wherein at least a portion of each of the polymers (or their polymorphic modifications) of the polymer blend is in a molten state. The portion of the crystalline fraction that is molten can be more than 10% (preferably 25%) by weight of the entire crystalline fraction. The portion of the crystalline fraction that remains solid can be more than 10% (preferably 25%) by weight of the entire crystalline fraction.

[0064] In another embodiment, the texturing apparatus comprises: a yarn heating device for heating of the yarn before its texturing in the texturing apparatus; a third temperature sensor configured to sense a temperature of the yarn heating device; and a third controller coupled with the third temperature sensor, wherein the third controller is configured to control the yarn heating device such that the actual temperature of the yarn heating device is held at another desired temperature.

[0065] This embodiment may be advantageous, because it may provide for an advanced texturing process control and repeatability. Utilization of the yarn heating device can provide for an advanced control of the temperature of the yarn in the texturing process, since the yarn is heated not only in the texturing apparatus but by the heating device as well.

[0066] In another embodiment, the other desired temperature is higher than the desired temperature.

[0067] This embodiment may be advantageous, because such a selection of the other desired temperature may compensate for cooling of the yarn during its transportation from the yarn heating device to the texturing apparatus.

[0068] In another embodiment, the texturing apparatus comprises an inlet port for receiving the yarn, wherein the other desired temperature is selected such that cooling of the yarn during its transportation from the yarn heating device to the inlet port is compensated in order to provide at the inlet port the yarn having the desired temperature. The other desired temperature can be 0.3 - 2 degrees Celsius higher than the desired temperature, preferably 0.3 - 1 degree Celsius higher than the desired temperature, more preferably 0.3 - 0.5 degree Celsius higher than the desired temperature.

[0069] In another embodiment, the texturing apparatus or the expansion chamber comprise a fluid flow sensor being configured to register an egress of the fluid through at least a portion of the sidewall.

[0070] This embodiment may be advantageous, because it may provide for a control of the clogging of the pores of the expansion chamber by the debris generated by the texturing process, wherein the control is performed during the texturing process. The registration of the fluid flow being below a predefined threshold value may indicate, that the pores of the expansion chamber are clogged and the expansion chamber has to be replaced by a new or a cleaned one.

[0071] In another aspect the invention provides for a system for manufacturing of an artificial turf. The system comprises the texturing apparatus for gas-dynamic texturing of an artificial turf yarn as described above and/or further in the text; and a system for attaching of the textured artificial turf yarn to a backing of the artificial turf.

[0072] Such a system may be advantageous because it comprises the texturing apparatus with advanced texturing process stability, which can provide for a manufacturing of the artificial turf with advanced quality, e.g. improved uniformity of the textured artificial turf yarn of the artificial turf.

[0073] In another aspect the invention provides for a method of manufacturing a textured yarn (e.g., a textured artificial turf yarn or a textured yarn for textile manufacturing) using the texturing apparatus for gas-dynamic texturing of the yarn. The method comprises texturing the yarn using the texturing apparatus described herein to provide the textured yarn, wherein the first controller of the texturing apparatus may be configured to control the heating device such that the temperature of the texturing apparatus is held at the desired temperature. The texturing may comprise the following: injecting a fluid under pressure into the texturing apparatus via the fluid inlet, injecting a yarn into the texturing apparatus via the yarn inlet port of the texturing apparatus, and subjecting, inside the gas-dynamic yarn texturing expansion chamber, the flowing yarn to a turbulent flow of the fluid so that the texturing of the flowing yarn occurs. The artificial turf yarn may have, for instance, a width of 1-1.1 mm and a thickness of 0.09-0.11 mm. The artificial turf yarn weight may typically reach 1000 dtex, (whereas the full yarn count range may be 50-3000 dtex).

[0074] This method may be advantageous because it employs the texturing system with advanced texturing process stability, as a result thereof the textured yarn may have advanced properties such as reduced variation of textured yarn properties over its length caused by temperature effects.

[0075] In another embodiment, the method further comprises: heating the texturing apparatus by a heating device in order to maintain a temperature of the texturing apparatus at a desired temperature, manufacturing the yarn; and repeating a procedure at predefined or varying time intervals. The procedure can be repeated/executed when at least one of the following criteria is complied with: a) a flow of the fluid egressing through at least a portion of the sidewall is below a predefined value; b) the texturing of the yarn is performed for a predefined time interval; and c) a predefined length of the yarn is textured by performing the texturing of the yarn. The procedure comprises: interrupting the texturing of the yarn by terminating the injecting of the yarn being manufactured into the texturing apparatus and guiding the yarn being manufactured away from the texturing apparatus; substituting the gas-dynamic yarn texturing expansion chamber by another gas-dynamic yarn texturing expansion chamber in the texturing apparatus after the interrupting of the texturing of the yarn; resuming the injecting of the yarn being manufactured into the texturing apparatus after the substituting of the gas-dynamic yarn texturing expansion chamber by the other gas-dynamic yarn texturing expansion chamber in the texturing apparatus; and resuming the texturing of the yarn after the resuming of the injecting of the yarn being manufactured and when the temperature of the texturing apparatus is at the desired temperature.

[0076] The heating device can be the heating device of the texturing apparatus, in particular one or more heating devices for heating the respective components of the texturing apparatus. The desired temperature mentioned in the method can be the aforementioned desired temperature. The flow of the fluid can be registered by the aforementioned fluid flow sensor.

[0077] This embodiment may be advantageous because the heating device may reduce a ramp-up time of the texturing apparatus after the substitution of the expansion chamber. As a result thereof, a volume of the manufactured yarn which is not processed by the texturing apparatus during the substitution of the expansion chamber is reduced. Reduction in the fluid flow may indicate that the porous sidewall is clogged and the gas-dynamic properties of the fluid flow in the expansion chamber have changed. In turn, the change in the gas-dynamic properties may result in a change in properties of the textured yarn. The criteria b) and c) provide for a simple approach determining the need to exchange the expansion chamber. This approach may be of particular advantage, when a big volume of the same textured yarn has to be manufactured. In this case, the step of the substituting of the expansion chamber by another expansion chamber is executed a lot of times throughout the manufacturing process. Thus the manufacturing process may be very well studied and optimized, thereby providing sufficient data for determination of the lifetime of the expansion chamber on a basis of duty time (criterion b)) or a length of the manufactured textured yarn (criterion c)).

[0078] In another embodiment, the method further comprises:

• registering a temperature of the texturing apparatus before the interrupting of the texturing of the yarn;
• heating the texturing apparatus up to the registered temperature using a heating device configured to heat the texturing apparatus by electromagnetic induction or through physical contact with the texturing apparatus, wherein the heating of the texturing apparatus up to the registered temperature is performed after the substituting of the expansion chamber by the other expansion chamber in the texturing apparatus and before the resuming of the texturing of the yarn.

[0079] In another embodiment the polymers of the polymer blend are different types of polyethylene. The types of the polyethylene can be but are not limited to: High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), Very-low-density Polyethylene (VLDPE).

[0080] This embodiment may be advantageous because polyethylene may have superior properties for manufacturing of the textured yarn in comparison with other polymers. Particularly, linear polyethylene (e.g. LLDPE or/and HDPE) offers a wide range of physical material properties, covering the technical requirements of artificial turf yarn. The density of linear polyethylene can be widely modified by co-monomers. The molecular weight distribution can be controlled with catalysts and by polymerization process management. Blending different types of polyethylene broadens the variability further. In particular, LLDPE is blended, i. e. mixed, with compatible material, such as VLDPE and/or HDPE with densities different from LLDPE. It may also be possible to blend different types of LLDPE.

[0081] Utilization of polymer blends comprising different types of polyethylene may provide for a balance between stability and softness of the textured yarn. Stability means in this context stiffness, wear resistance, hardness, resilience, etc., whereas softness means flexibility, elasticity, smoothness, etc. Blending different materials each with the required stability or softness may result in the properties providing the required balance between stability and softness.

[0082] In another embodiment the method further comprises raising the temperature of the yarn to a temperature within the temperature range (of the texturing process) using one or more godets (such as, for instance, the yarn heating device).

[0083] This embodiment may be advantageous because it may provide for an improved process control, since the yarn is preheated in order to provide the yarn entering the texturing apparatus, wherein both the texturing apparatus and the artificial turf yarn have the same temperature or substantially similar temperatures.

[0084] In another embodiment the method further comprises drawing (stretching) the yarn, e.g. to a factor of 4 - 6.5.

[0085] This embodiment may be advantageous because it may provide for an increase in crystallinity of the yarn (e.g. an increase in crystallinity of at least one of the polymers of the polymer blend used for the manufacturing of the yarn). In the other words, the size of crystalline portions of the yarn (or at least one of the polymers of the polymer blend) is increased relative to the size of amorphous portions of the yarn. As a result the yarn or at least of the polymers of the polymer blend become more rigid. The stretching of the yarn can further cause reshaping of fragments (e.g. beads) of one of the polymers of the polymer blend used for the manufacturing of the yarn such that they have thread like regions, which can make impossible delamination of different polymers in the yarn from each other, in particular when immiscible polymers are used in the polymer blend. This embodiment may also be advantageous, because the drawing (stretching) process of the yarn can give rise to polymorphism, i. e. crystallographic unit cell modification. For instance the drawing process can result in forming triclinic crystal modification of polyethylene in addition to orthorhombic crystal modification of polyethylene formed after extruding and cooling.

[0086] This drawing of the artificial turf yarn causes the yarn to become longer and in the drawing process the fragments of one of the polymers of the polymer blend (e.g. beads) are stretched and elongated. Depending upon the amount of stretching the fragments of one of the polymers (e.g. beads) of the polymer blend are elongated more.

[0087] In another embodiment the method further comprises extruding the polymer blend into the yarn using in the steps of the method of manufacturing the textured yarn .

[0088] This embodiment may be advantageous, because it may provide for manufacturing of the yarn out of a broad spectrum of polymers including immiscible polymers.

[0089] In another embodiment the method further comprises creating the polymer blend, wherein the polymer blend is at least a three-phase system, wherein the polymer blend comprises a first polymer, a second polymer, and a compatibilizer, wherein the first polymer and the second polymer are immiscible, wherein the first polymer forms polymer beads surrounded by the compatibilizer within the second polymer.

[0090] In a specific example the first polymer could be polyamide and the second polymer could be polyethylene. Stretching the polyamide will cause an increase in the crystalline regions making the polyamide stiffer. This is also true for other semi-crystalline plastic polymers.

[0091] In another embodiment, the first polymer comprises (or consists of) polyamide (PA) and the second polymer comprises (or consists of) polyethylene (PE). The first polymer may comprise at least 90 weight percent of PA. The second polymer can comprise at least 90 weight percent of PE. The polymer mixture can comprise at least 30 weight percent of PE and/or at least 30 weight percent of PA.

[0092] In another embodiment, the first polymer comprises (or consists of) polyester and the second polymer comprises (or consists of) PE. The first polymer may comprise at least 90 weight percent of polyester. The second polymer can comprise at least 90 weight percent of PE. The polymer mixture can comprise at least 30 weight percent of PE and/or at least 30 weight percent of polyester.

[0093] In another embodiment, the first polymer comprises (or consists of) polyester and the second polymer comprises (or consists of) polypropylene (PP). The first polymer may comprise at least 90 weight percent of polyester. The second polymer can comprise at least 90 weight percent of PP. The polymer mixture can comprise at least 30 weight percent of PP and/or at least 30 weight percent of polyester.

[0094] In another embodiment, the first polymer comprises (or consists of) PA and the second polymer comprises (consists of) PP. The first polymer may comprise at least 90 weight percent of PA. The second polymer can comprise at least 90 weight percent of PP. The polymer mixture can comprise at least 30 weight percent of PP and/or at least 30 weight percent of PA.

[0095] These embodiments related to the polymer blends/mixtures may be advantageous because it may enable utilization of a broader spectrum of polymers for manufacturing of the monofilament yarn such that the properties of the artificial turf fiber can be tailored. As it is mentioned above different polymers of the polymer blend can provide for different properties of the textured yarn. One polymer can provide for the stability and/or the resilience (e.g. the ability to spring back after being stepped or pressed down), while another polymer can provide for the softness (e.g. the softer or a grass-like feel).

[0096] These embodiments related to the polymer blends/mixtures may have a further advantage that the second polymer and any immiscible polymers may not delaminate from each other. The thread-like regions can be embedded within the second polymer. It is therefore impossible for them to delaminate.

[0097] A further advantage may possibly be that the thread-like regions are concentrated in a central region of the monofilament during the extrusion process. This may lead to a concentration of the more rigid material in the center of the monofilament yarn and a larger amount of softer plastic on the exterior or outer region of the monofilament yarn. This may further provide for an artificial turf fiber with more grass-like properties, when the artificial turf fiber is made of the textured monofilament yarn.

[0098] A further advantage may be that the artificial turf fibers made of the textured monofilament yarn have improved long term elasticity. This may require reduced maintenance of the artificial turf and less brushing of the fibers because they more naturally regain their shape and stand up after mechanical use.

[0099] In another embodiment the creating of the polymer blend comprises the steps of: forming a first blend by mixing the first polymer with the compatibilizer; heating the first blend; extruding the first heated blend; granulating the extruded first blend; mixing the granulated first blend with the second polymer; and heating the granulated first blend with the second polymer to form the polymer blend. This particular method of creating the polymer mixture may be advantageous because it enables very precise control over how the first polymer and compatibilizer are distributed within the second polymer. For instance the size or shape of the extruded first mixture may determine the size of the polymer beads in the polymer mixture.

[0100] This embodiment may be advantageous, because a so called single-screw extrusion method may be used. As an alternative to this, the polymer blend may also be created by putting all of the components that make it up together at once. For instance the first polymer, the second polymer and the compatibilizer could be all added together at the same time. Other ingredients such as additional polymers or other additives could also be put together at the same time. The amount of mixing of the polymer blend could then be increased for instance by using a twin-screw feed for the extrusion. In this case the desired distribution of the polymer beads can be achieved by using the proper rate or amount of mixing.

[0101] In another embodiment the polymer blend is at least a four phase system, wherein the polymer blend comprises at least a third polymer, wherein the third polymer is immiscible with the second polymer, wherein the third polymer further forms the polymer beads surrounded by the compatibilizer within the second polymer.

[0102] This embodiment may be advantageous because it may enable utilization of an even broader spectrum of polymers for manufacturing of the monofilament yarn. As it is mentioned above different polymers of the polymer blend can provide for different properties of the textured yarn. One polymer can provide for the stability, while another polymer can provide for the softness. This particular embodiment can provide for combining in a final product properties of at least three polymers.

[0103] In another embodiment the creating of the polymer blend comprises the steps of: forming a first blend by mixing the first polymer and the third polymer with the compatibilizer; heating the first blend; extruding the first heated blend; granulating the extruded first blend; mixing the first blend with the second polymer; and heating the mixed first blend with the second polymer to form the polymer blend.

[0104] This embodiment may be advantageous because it may provide for an effective procedure for manufacturing of the polymer blend comprising multiple polymers. As an alternative the first polymer could be used to make a granulate with the compatibilizer separately from making the third polymer with the same or a different compatibilizer. The granulates could then be mixed with the second polymer to make the polymer mixture. As another alternative to this the polymer mixture could be made by adding the first polymer, a second polymer, the third polymer and the compatibilizer all together at the same time and then mixing them more vigorously. For instance a two-screw feed could be used for the extruder.

[0105] In another aspect the invention provides for a textured yarn (e.g., a textured artificial turf yarn and/or a textured monofilament yarn) manufactured as described above. In particular, utilization of the aforementioned texturing apparatus may provide for advanced properties of the textured artificial yarn and/or improved manufacturing repeatability, because it provides for the advanced uniformity of gas-dynamic properties of fluid flow in the expansion chamber and the advanced temperature control of the texturing process. For instance, the yarn, as described herein, can comprise a polymer blend comprising at least two polymers having close melting temperatures (e.g. the DSC curves of these polymers substantially overlap each other). In this case the accurate (fine) control of the temperature of the texturing apparatus in conjunction with the advanced uniformity of gas-dynamic properties in the expansion chamber might be important in order to precisely control the portion of a crystalline fraction of the blend being in a molten state and the portion of the crystalline fraction of the blend being in a solid state when the gas-dynamic texturing is performed in conjunction with uniformity of forces exerted on the yarn by a turbulent flow of the fluid in the expansion chamber. Moreover, employing the aforementioned texturing apparatus may result not only in said property and/or repeatability improvement, but enable utilization of polymer blends for manufacturing of textured yarn using the gas-dynamic process, which are impossible to utilize for manufacturing of textured yarn using conventional texturing systems providing only coarse control of the texturing process.

[0106] In another aspect the invention provides for a method of manufacturing an artificial turf, wherein the method comprises: manufacturing the textured artificial turf yarn as described above; tufting the textured artificial turf yarn into a backing of the artificial turf. The artificial turf backing may for instance be a textile or other flat structure which is able to have fibers tufted into it. The textured artificial turf yarn may also have properties or features which are provided for by any of the aforementioned method steps.

[0107] In another aspect the invention provides for an artificial turf manufactured according to the method for manufacturing of the artificial turf according to the aforementioned method of manufacturing an artificial turf.

Brief description of the drawings

[0108] In the following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:

Fig. 1 illustrates an example of a system for manufacturing of a textured artificial turf yarn;

Fig. 2. Illustrates an example plate for extruding of a monofilament yarn

Fig. 3 illustrates an example drawing device;

Fig. 4 illustrates an example cross-section of a monofilament yarn;

Fig. 5 illustrates an example cross-section of a monofilament yarn;

Fig. 6 illustrates an example texturing apparatus;

Fig. 7a illustrates cross-sections of expansion chambers;

Fig. 7b illustrates an expansion chamber made of sintered bronze granules and a mold for sintering the expansion chamber;

Fig. 8 illustrates an example step-up for evaluation of fluid permeability through various sections of an expansion chamber;

Fig. 9 illustrates an photo of a textured artificial turf yarn;

Fig. 10 illustrates a flow chart of a method;

Fig. 11 shows a flow chart of a method;

Fig. 12 shows a flow chart of a method;

Fig. 13 shows a flow chart of a method;

Fig. 14 shows a flow chart of a method;

Fig. 15 shows a diagram which illustrates a cross-section of a polymer blend;

Fig. 16 shows a diagram which illustrates a cross-section of a polymer blend;

Fig. 17 shows an example of a cross-section of an example of artificial turf.

Detailed Description

[0109] Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

[0110] Fig. 1 illustrates an example system of manufacturing of a textured yarn 122 for using in applications such as for instance textile manufacturing or manufacturing of artificial turf. The system comprises: an extruder 100 (e.g. a screw-extruder) and a texturing system. The system can further comprise one or more drawing devices 115, 118, one or more thermosetting (or heating) devices (e.g. godets, ovens) 117, one or more cooling devices (e.g. godets, bathes with cooling liquid) 116, 120, 97, and one or more rollers 121.

[0111] The extruder 100 comprises at least one hopper 101 for feeding components of a monofilament yarn (e.g. a blend of polymers) into the extruder and one outlet 102 for the monofilament yarn. The outlet 102 can be implemented as a wide slot nozzle or a spinneret. A polymer melt formed in a chamber of the extruder is pressed through the outlet 102 to form a monofilament yarn of a specific shape. A fragment of the wide slot nozzle or the spinneret is depicted in Fig. 2.

[0112] Fig. 2 illustrates the extrusion of the polymer mixture into a monofilament. Shown is an amount of polymer blend 96. Within the polymer blend 96 there is a large number of portions 138 of a first polymer of the polymer blend 96 being at least partially embedded in a second polymer 137 of the polymer blend 96. A screw, piston or other device of the extruder 100 is used to force the polymer mixture 96 through a hole 95 in a plate 102a. This causes the polymer blend 96 to be extruded into a monofilament yarn 119. The monofilament yarn 119 is shown as containing fragments 138 of the first polymer of the polymer blend 96 as well. The both of the polymers of are extruded together.

[0113] In some examples the polymer blend can have different compositions. Within the polymer blend 96 there is a large number of polymer beads 138. The polymer beads 138 may be made of one or more polymers which are not miscible with the second polymer 137 and also separated from the second polymer 137 by a compatibilizer. A screw, piston or other device is used to force the polymer blend 96 through a hole 95 in a plate 102a. This causes the polymer blend 96 to be extruded into a monofilament yarn 119. The monofilament yarn 119 is shown as containing polymer beads 138 also. The second polymer 137 and the polymer beads 138 are extruded together. In some examples the second polymer 137 will be less viscous than the polymer beads 138 and the polymer beads 138 will tend to concentrate in the center of the monofilament yarn 119. This may lead to desirable properties for the final artificial turf fiber as this may lead to a concentration of the thread-like regions in the core region of the monofilament yarn 119.

[0114] The monofilament yarn can be cooled down after the extrusion using the cooling device 97. When the cooling device is implemented as a godet, it can comprise two rollers 99 and 98 for winding the monofilament yarn 119. The cooling process can be implementing by maintaining a temperature of the rollers 99 and 98 within the specified range and/or by air cooling and/or by water cooling. A temperature of water (or air) can be kept within a specified range as well. Alternatively the cooling device can be a bath with a cooling liquid (e.g. water) in which the monofilament yarn is cooled. The monofilament yarn is cooled down using the cooling device 97 to a temperature where crystallization can take place. In the crystallization process the crystallites are forming to a percentage, which depends on the cooling rate. The higher the cooling rate, the less is the crystallinity and vice versa.

[0115] The monofilament yarn can be further drawn using the drawing device 115. The drawing device can comprise three rollers 104, 103, 105. The drawing ratio is defined as the ratio of linear speeds of a pair of rollers 103 and 104 (or 104 and 105). The drawing device 115 can be operable for heating the monofilament yarn 119 during or before the drawing process. This can be implemented by heating one or more the rollers in order to keep their temperature within a predetermined temperature range and/or by air heating, wherein the hot air has a temperature within a predetermined temperature range. The elongation of the monofilament yarn in the drawing device can force the macromolecules of the monofilament yarn to parallelize. This results in a higher degree of crystallinity and increased tensile strength, compared with undrawn monofilament yarn.

[0116] Fig. 3 depicts an alternative implementation 115a of any of the drawing devices mentioned herein (e.g. the drawing device 115 or 118). The drawing device comprises one or more feeding rollers 81 - 83, an oven 80, and one or more receiving rollers 84-86. The one or more feeding rollers are configured to feed the monofilament yarn 119 into the oven. The one or more receiving rollers are configured to receive the monofilament yarn from the oven. The oven is configured to heat the monofilament yarn. The drawing ratio is determined by a ratio of the linear speeds of the feeding roller 83 being the last roller before the oven and the receiving roller 84 being the first after oven. The thermosetting process (drawing process) is performed in the oven 80, in which the monofilament yarn in stretched and heated simultaneously.

[0117] Fig. 4 depicts a not to scale cross-section of a segment the monofilament yarn 136 before its processing in the drawing device 115, whereas Fig. 5 depicts a not to scale cross-section of a segment of the monofilament yarn 140 after its processing in the drawing device 115. Before the drawing process the fragments of the first polymer 138 can have an arbitrary shape, e.g. a shape of beads. The fragments of the first polymer are at least partially incorporated in the second polymer 137. After the drawing process the fragments of the first polymer 138 have elongated shape in comparison to the fragments of the first polymer 138 before the drawing process.

[0118] Turning back to Fig. 1, the monofilament yarn can be further cooled using the cooling device 116. The cooling device, when implemented as a cooling godet can have rollers 106 and 107. The cooling device can be built and/or function in the same way as the cooling device 97. Afterwards the monofilament yarn can be further drawn using the drawing device 118 having rollers 110, 111, and 112. The drawing device 118 can be built and/or function in the same way as the drawing device 115.

[0119] The monofilament yarn can be further heated using one or more heating devices or elements (e.g. device 117). The heating device comprises a heater (or a heating device) and a temperature sensor for sensing a temperature of the heater (or the heating device). The heater can be implemented as an electrical resistance heater. The heating device is controlled by a controller (e.g. controller 152) such that the temperature of the heater is kept at a desired temperature (this temperature is mentioned herein as the other desired temperature as well). The controller comprises a computer processor 153 and memory 154 comprising instructions executable by the computer processor. The controller is communicatively coupled to the heating device and the temperature sensor configured to sense a temperature of the heating device. The communicative coupling can be implemented via a computer network or a data bus 155. The controller is operable to hold an actual temperature of the heating device at the other desired temperature. The other desired temperature can be selected such that the yarn cooled during a transportation from the heater to the texturing apparatus (e.g. distance 156) has a temperature of the texturing process (this temperature is mentioned herein as the desired temperature as well) when it enters the texturing apparatus 114, or its inlet port 124 for receiving the yarn. In this case the third desired temperature is higher than the temperature of the texturing process. The execution of the computer instructions by the computer processor 153 causes the controller to hold the process temperature at the desired temperature. The control of the process temperature can be implemented as follows. The controller reads out the temperature of the heater sensed by the temperature sensor. The temperature of the heater is used as a feedback signal for setting the temperature of the heating device 117 in order to provide the heating of the monofilament yarn to the other desired temperature. The functioning of this feedback loop can be implemented using a proportional-integral-derivative algorithm. The other third desired temperature can be specified as a temperature range. In this case the holding of the actual temperature at the other desired temperature comprises keeping the actual temperature within the specified range, in particular the actual temperature is kept as close as possible to a middle temperature of the temperature range. The middle temperature is equal to an average of a lower boundary of the temperature range and an upper boundary of the chosen temperature range.

[0120] The heating device 117, when implemented as a godet, comprises a pair of rollers 108 and 109. The heating of the monofilament yarn can be made by keeping a temperature of the rollers within a predetermined temperature range and/or by hot air having a temperature within a predetermined temperature range. For instance the roller 109 can be equipped with a heater 150 and a temperature sensor 151 both communicatively coupled to the controller 152.

[0121] A controller 70 is configured to control a temperature of the texturing apparatus 114. The controller 70 comprises a computer processor 72 and memory 73 comprising instructions executable by the computer processor. The controller is communicatively coupled to the temperature sensor 158 configured to sense a temperature of the texturing apparatus 114, and a heating device, 129. The heating device can be configured to heat the texturing device through physical contact between the texturing device and the heating device or by electromagnetic induction. The physical contact can be a direct physical contact or a contact in which a thermally conductive paste is used between the heating device 129 and the texturing apparatus 114. At least a portion of the texturing device can be placed inside or in the proximity of the electromagnet of the heating device configured to heat the texturing device by electromagnetic induction. The heating device can be implemented as an electrical resistance heater. Further heating devices and temperature sensors which can be operated by the controller 70 (or other controllers) are depicted on Fig. 6. The communicative coupling can be implemented via a computer network or a data bus 71. The controller is operable to hold an actual temperature of the texturing apparatus at a desired temperature which can be the temperature required for the texturing process (this desired temperature is mentioned as the desired temperature herein as well). The desired temperature can be specified as a temperature range. In this case the holding of the actual temperature at the desired temperature comprises keeping the actual temperature within the specified range, in particular the actual temperature is kept as close as possible to a middle temperature of the temperature range. The middle temperature is equal to an average of a lower boundary of the temperature range and an upper boundary of the chosen temperature range. The execution of the computer instructions by the computer processor 72 causes the controller to hold the texturing apparatus temperature at the desired temperature. The control of the texturing apparatus temperature can be implemented as follows. The controller reads out the temperature of the texturing apparatus sensed by the temperature sensor 158. The temperature of the texturing apparatus is used as a feedback signal for setting the temperature of the heating device 129 in order to provide the heating of the texturing apparatus to the desired temperature. The functioning of this feedback loop can be implemented using a proportional-integral-derivative algorithm.

[0122] The texturing apparatus 114 has an inlet 130 for a fluid under pressure used for the texturing process. The fluid can be hot air, i.e. air above ambient temperature. The hot fluid under pressure can be produced by a compressor 166 and a heating device 165 for heating the fluid, whereas a flow of the fluid is controlled by a fluid flow regulator 179. The heating device can be implemented as an electrical resistance heater. The compressor 166, the fluid flow regulator 179, and the heating device are connected in series by a gas pipe line to the inlet 130. A temperature and a flow of the fluid entering the texturing apparatus can be controlled by controller 162 comprising a computer processor 163 and a memory 164 storing processor executable instructions. The controller 162 is communicatively coupled to the heating device 165, the fluid flow regulator, and a temperature sensor 131 configured to sense a temperature of the fluid in the texturing apparatus (or in the inlet 130). The communicative coupling can be implemented via a computer network or a data bus 167. The controller is operable to hold an actual temperature of the fluid at a desired temperature which can be the temperature required for the texturing process (this desired temperature is mentioned as the desired temperature herein as well). The desired temperature can be specified as a temperature range. In this case the holding of the actual temperature at the desired temperature comprises keeping the actual temperature within the specified range, in particular the actual temperature is kept as close as possible to a middle temperature of the temperature range. The middle temperature is equal to an average of a lower boundary of the temperature range and an upper boundary of the chosen temperature range. The execution of the computer instructions by the computer processor 163 causes the controller 162 to hold the temperature of the fluid at the desired temperature. The control of the fluid temperature can be implemented as follows. The controller reads out the temperature of the fluid sensed by the temperature sensor 131. The temperature of the fluid is used as a feedback signal for setting the temperature of the heating device 165 in order to provide the heating of the fluid to the second desired temperature. The functioning of this feedback loop can be implemented using a proportional-integral-derivative algorithm.

[0123] After the heating using one or more heating devices 117 the monofilament yarn is textured in the texturing apparatus114. The textured monofilament yarn 122 egressing the texturing apparatus 114 is guided by a yarn guide tube 148 to a cooling godet 120 configured to cool the textured yarn. The cooling can be performed by keeping a temperature of a roller 120 of the cooling godet within a predetermined temperature range and/or by air having a temperature within a predetermined temperature range. The textured monofilament yarn 122 can be forwarded further to another roller 121 for further processing.

[0124] The sequence of optional processing units, i.e. the cooling godet 97, the drawing device 115, the cooling godet 116, the drawing device 118, the heating godet 117, can be different. It depends on particular processing steps required for preprocessing steps before the texturing process. Additional drawing devices, and/or heating devices, and/or cooling devices can be included. For instance several heating devices can be used instead of the single heating device 117 depicted in Fig. 1 in order to provide for a gradual heating of the monofilament yarn 119. Alternatively, the preprocessed monofilament yarn can be used for the texturing. In this case there can be no need of the extruder 100, the cooling devices 97 and 116, and the drawing device 115. When drawing process can be executed in several steps, several drawing devices 115 can be used in series. The system depicted in Fig. 1 can be compatible with reel-to-reel manufacturing. For instance, the yarn can be wound on reels after its processing using the cooling godet 97 and/or 116. The yarn can be unwound from reels for further processing in the drawing device 115 and/or 118. Alternatively the system can produce the textured yarn without intermediate reel-to-reel operations. The yarn can flow without any interruptions from the extruder 100 to the texturing apparatus. In this operation modus the yarn being manufactured (i.e. the yarn flow) is guided away from the texturing apparatus 114 during a maintenance procedure of the texturing apparatus 114, which details are discussed further in greater detail. After the maintenance procedure is completed and the texturing apparatus is prepared for further texturing the yarn can be fed into the texturing apparatus again. The yarn guided away from the texturing apparatus during the maintenance procedure can be recycled, e.g. it can be used in the extruder for further yarn manufacturing.

[0125] At least some of the processing units of the system depicted in Fig. 1 can be operated as stand-alone processing units (or groups of units), wherein each of the units (or groups of units) is configured to perform a particular operation, such as extruding, drawing, or texturing. In this case the process can be implemented as reel-to-reel process, wherein yarn is winded on a reel after completion of the operation and winded off the reel for processing the yarn in the next operation. For instance, the extruding process can be performed using the extruder 100 and the cooling device. The texturing process can be executed using a texturing system comprising the texturing apparatus 114 equipped with the heating device 129 and the temperature sensor 158 configured to sense the temperature of the texturing apparatus. In addition the texturing process can be executed using fluid heating device 165 controlled by the controller 162 and/or the yarn heating device 150 controller by the controller 152.

[0126] The processing units can be configured such that they process/produce several monofilaments in parallel. For instance, several monofilaments can be extruded in parallel using the extruder 100. In this case the spinneret has several holes (e.g. holes like hole 95 depicted in Fig. 2). The drawing device 115 can be configured to process several monofilaments in parallel. For instance, the rollers 103-105 can be made broad enough to process several monofilaments in parallel. The same approach can be used for the other units 116, 118, 117, and 115a equipped with rollers 81-86, 106, 107, 110-112, 108, 109. The texturing apparatus 114 can be configured to process several monofilaments in parallel as well. The monofilaments can be fed into the texturing apparatus through the inlet port 124 of the texturing apparatus 114. After the texturing the monofilaments can be cooled down using the cooling godet 120.

[0127] At least some of the processing units of the system depicted in Fig. 1 can be components of a system for manufacturing of an artificial turf. In addition the system for manufacturing of the artificial turf comprises a system for attaching of a textured artificial turf yarn to a backing of the artificial turf. The textured artificial turf yarn can be manufactured using the texturing system. The system for attaching of the textured artificial turf yarn to the backing can comprise a tufting machine being configured to tuft the textured artificial turf yarns through the backing (e.g. stitch/knit the yarns into a sheet of a woven material). The system can further comprise a coating system configured to coat the backing on its back side to adhere the textured artificial turf yarns to the backing. The coating may comprise at least one of acrylic, polyurethane, latex or some combination thereof to assist in preventing the yarns from undesirably detaching from the artificial turf with extended use. The system for attaching of the textured artificial turf yarn to the backing can further comprise another system configured to produce an infill layer of a particular material atop the backing and dispersed among the artificial turf yarn such that portions of the textured artificial turf yarn extend above the infill layer. Utilization of either the backside coating or the infill layer can be optional.

[0128] Fig. 6 depicts the texturing apparatus 114 in greater detail. The texturing apparatus comprises a housing 123. The housing can be a hollow elongated member, which can be implemented as pipe. The pipe may have a length of 0,15 m and a diameter of 0.015 m. The inlet port (injector jet) 124 for yarn ingress is arranged on one end of the elongated member, whereas an expansion chamber 147 is arranged on another end of the elongated member. The expansion chamber may have a tubular form having one or more adjacent hollow cylindrical shapes. An inlet 130 for the fluid under pressure used for the texturing process is arranged on a side wall of the elongated member, wherein the inlet 130 is configured for infeed of the fluid inside the housing. The inlet 130 can be a pipe, wherein one end of the pipe has an opening arranged for connecting to the gas pipe line 161 and another end of the pipe has another opening connecting the interiors pipe with the housing. The temperature sensor 131 for sensing the temperature of the fluid can be located in the inlet 130 (or in the pipe of the inlet 130).

[0129] A yarn channel 126 is arranged within the housing. The yarn channel can be implemented as a hollow elongated member, e.g. a pipe or conduit. An end portion 125 of the yarn channel has an increasing inner diameter such that an end of the yarn channel has a bigger diameter than a diameter of the yarn channel outside the end portion. The end portion 125 can be funnel shaped. The inlet port 124 is arranged such that it has a threaded bushing 177 for regulating its position in the housing. The inlet port has a channel 178 for infeed of yarn 119 into the yarn channel 126. The inlet has a conical shape 159 adjacent to a portion of the inlet which has the threaded bushing 177. A surface of the conical shape and an inner wall of the end (funneled) portion constitute a channel 176 for infeed of the fluid into the yarn channel 126. The surface of the conical shape and the inner wall of the end portion can be parallel to each other. The inlet port 124 is arranged such that rotation of the threaded bushing 177 results in a change in a distance between the surface of the conical shape and the inner wall of the (funneled) end portion, i.e. in a change in a cross-section of the channel 176. This functionality can be used for tuning of the fluid flow in the yarn channel 126 towards the expansion chamber 147. The texturing apparatus 114 is arranged such that an inner wall of the housing 123 and an outer wall of the yarn channel 126 constitute a channel 127 for guiding the fluid from the inlet 130 into the yarn channel 126 via the channel 176. A temperature sensor 128 for sensing the temperature of the fluid can be positioned in the channel 127. The temperature sensor 128 can be used instead temperature sensor 130 for controlling the temperature of the fluid by the controller 162.

[0130] The texturing apparatus comprises means for entraining of the yarn 119 (e.g. artificial turf yarn or yarn for textile manufacturing) so that it runs concurrently with the fluid in the yarn channel 126. These means can be constituted by the channel 176 in the end (funnel) portion of the yarn channel 126, the channel 178 of the inlet port 124, wherein the channel 178 has an opening in the end (funnel) portion 159 as well. The fluid guided by the channel 176 enters the yarn channel 126 and entrains the yarn 119 into the yarn channel 126, whereas the yarn is fed into the texturing apparatus 114 via the channel 178 of the inlet port 124. In other words, the yarn is transported downstream the yarn channel by the intake of the fluid. Both, the yarn and the fluid move downstream to the expansion chamber 147 of the texturing apparatus 114. The fluid stream exerts a tractive force on the monofilaments (yarn strands) such that they are aspirated into the channel 178 of the inlet port (injector jet) 124.

[0131] The expansion chamber 147 leads out of the yarn channel 126 downstream thereof. A downstream circular outlet opening of the yarn channel 126 is adjacent to a circular inlet opening 182 of an inlet 171 of the expansion chamber 147, wherein a center of the downstream circular outlet opening of the yarn channel 126 coincides with a center of the circular inlet opening 182 of the inlet 171 of the expansion chamber and a diameter of the downstream circular outlet opening of the yarn channel 126 is less than a diameter of the circular inlet opening 182 of the inlet 171 of the expansion chamber. Such a configuration of the yarn channel 126 and the expansion chamber constitute a discrete increase in diameter downstream the fluid flow, which acts as a diffuser for the fluid flow.

[0132] The texturing apparatus has a release mechanism for attachment/detachment of the expansion chamber 147 to the texturing apparatus, in particular to its housing 123. The release mechanism can be implemented in various ways. The expansion chamber 147 may be positioned partially within the housing 123, in particular at least a portion of the inlet 171 of the expansion chamber is positioned within the housing 123, when the expansion chamber 147 is attached to the housing 123. Such a configuration may enable non-positive or frictional connection (e.g. spigot-socket fitting connection) of the expansion chamber to the housing. In the example depicted in Fig. 6 the inlet 171 (i.e. a spigot) of the expansion chamber 147 has an outer diameter which tightly fits into a tubular end section (i.e. a socket) of the housing. The tight fitting may generate sufficient friction force providing attachment of the expansion chamber 147 to the housing 123. The fitting may be threaded or unthreaded. Alternatively the release mechanism can be implemented as a clamping mechanism. The clamping mechanism depicted in Fig. 6 is implemented as a thread 133 in the tubular end section of the housing 123 and a screw 160. The screw 160, when screwed in the thread 133, exerts a clamping force on the inlet 171 that keeps the expansion chamber 147 attached to the housing 123. In order to avoid deformation of the inlet 171 by the clamping force, the inlet can be manufactured out of a material, which has a higher degree of hardness, than material out which the porous sidewall of an expansion chamber section 170 adjacent to the inlet 171. The inlet 171 can be made solid or have a lower porosity than the sidewall, because the inlet 171 is positioned within the tubular end section housing which is impermeable for the fluid.

[0133] When the yarn and the fluid enter the expansion chamber 147 the flow of the fluid is separated from the wall and outer layers of the flow build vortices or eddies with areas of reversed flow, i.e. the fluid builds a turbulent flow near a surface of the expansion chamber. Inside the expansion chamber the yarn follow the direction of the fluid flow and are thereby deformed. In a downstream portion of the expansion chamber 147 the deformed (textured) yarn is further deformed by the turbulent flow, in addition it is decelerated and forms a yarn plug. The yarn plug is disintegrated in the lower end of the expansion chamber. A portion of the fluid 149 and the textured yarn 122 of the disintegrated plug egress through a downstream outlet 181 of the expansion chamber 147. The textured yarn egressing though the downstream outlet 181 is guided by the guide tube 148 to the cooling device 120. The guide tube 148 may be connected to the expansion chamber 147 in a similar way as the expansion chamber 147 is connected to the housing 123 using another release mechanism. For instance, the connection of the guide tube 148 to the expansion chamber 147 may be a releasable spigot-socket fitting, friction, clamping, or non-positive connection. The fitting may be threaded or unthreaded. In the example depicted in Fig. 6, the downstream outlet 172 (i.e. a socket) of the expansion chamber 147 has a an inner diameter in which an outer surface of an upper/upstream section (i.e. a spigot) of the guide tube 148 fits tightly.

[0134] The downstream outlet 181 and the inlet 182 are connected by an inner channel 169 of the expansion chamber 147. The inner channel may have a constant diameter throughout its length. Alternatively, the inner channel may have a tapering in a direction from the downstream outlet 172 of the expansion chamber to the inlet 171 of the expansion chamber, i.e. a diameter of the inner channel may decrease in this direction.

[0135] The expansion chamber 147 comprises fluid exhaust means for egress of the fluid from the expansion chamber independently of egress of the artificial turf yarn. These means are needed because the cross-section of the expansion chamber is effectively blocked by the yarn plug. The exhaust means comprise a side wall of at least a section 170 of the expansion chamber 147. The side wall is porous to provide egress of a portion 135 of the fluid. The sidewall may constitute a section of the aforementioned inner channel. A fluid permeability of the sidewall may increase in the direction from the inlet to the downstream outlet of the expansion chamber.

[0136] Fig. 7a illustrates several non-limiting variants 147a-d of the expansion chamber 147. Each of the variants may have features of any other variant unless mutually exclusive. Each of the variants comprises the inlet 171, which may be used for the aforementioned connection to the housing 123 or the yarn channel 126, and a downstream outlet 172, which may be used for the aforementioned connection to the yarn guide tube 148. Each of the expansion chambers 147a-d comprises a middle section 170 having a porous sidewall, wherein the middle section is adjacent to the inlet 171 and the downstream outlet 172. The inlet 171 of any of the expansion chambers 147a-d may have a porous sidewall as well. However the fluid egress though the inlet may be blocked by the aforementioned connection to the housing 123. The downstream outlet 172 of any of the expansion chambers 147a-d may have a porous sidewall as well. However the fluid egress though the downstream outlet may be blocked by the aforementioned connection to the guide tube 148. The inlet 171 and the downstream outlet 172 of any of the expansion chambers are connected by an inner channel 169. The inner channel of any of the expansion chambers 147a, 147c, and 147d has a constant diameter, whereas the inner channel of the expansion chamber 147b has a tapering in a direction from the downstream outlet to the inlet, i.e. the a diameter of the inner channel decreases in this direction. A thickness and/or fluid permeability of the sidewall of the middle section 170 of any of the expansion chambers 147a and 147c is constant, whereas a thickness and/or fluid permeability of the sidewall of the middle section 170 of any of the expansion chamber 147b decreases in a direction from the inlet 171 to the downstream outlet 172.

[0137] The inlet 171, the downstream outlet 172, and the middle section 170 of the expansion chamber 147c each have sidewalls comprising two tubular layers each circumventing the inner channel 169 of the expansion chamber 147c. The downstream outlet 172 of the expansion chamber 147c comprises a portion of a layer 168a and a layer 168b. The portion of the layer 168a circumvents the inner channel 169 of the expansion chamber 147c, whereas the layer 168b circumvents the portion of the layer 168a and the inner channel 169 of the expansion chamber 147c. The middle section 170 of the expansion chamber 147c comprises another portion of a layer 168a and a layer 168c. The other portion of the layer 168a circumvents the inner channel 169 of the expansion chamber 117c, whereas the layer 168c circumvents the other portion of the layer 168a and the inner channel 169 of the expansion chamber 147c. The inlet 171 of the expansion chamber 147c comprises yet another portion of a layer 168a and a layer 168d. The yet other portion of the layer 168a circumvents the inner channel 169 of the expansion chamber 147c, whereas the layer 168d circumvents the yet other portion of the layer 168a and the inner channel 169 of the expansion chamber 147c. A material of the layer 168a may have higher porosity than a material of the layer 168c. The material of the layer 168a may have higher permeability than the material of the layer 168c. A surface roughness of the material of the layer 168a may be higher than a surface roughness than the material of the layer 168c. A portion of the expansion chamber comprising layers 168b-d can be made using one manufacturing process, whereas another portion of the expansion chamber comprising layer 168a can be made using another manufacturing process. The other portion can be inserted into the portion after manufacturing of both portions.

[0138] Different portions of the expansion chamber can be made out of different materials. For instance the inlet 171 and first section 170b of the middle section of the expansion chamber 147a are made of a first material, whereas the downstream outlet 172 and a second section 170a of the middle section are made of a second material. The first section 170b is positioned closer to the inlet 171 than the second section 170a. The second material can have a higher porosity and/or a higher fluid permeability than the first material.

[0139] A zone of turbulent flow 175 of the fluid is depicted in Fig. 7a for the variant of the expansion chamber 147a having the inner channel of constant diameter throughout the entire length of the expansion chamber 147a. The zone is located near the inner surface of the inner channel and gets thinner in the direction from the inlet 171 to the downstream outlet 172.

[0140] Only one heating device 129 and only one temperature sensor 158 for controlling the temperature of the texturing apparatus are depicted in Fig. 1. These components are depicted in Fig. 6 as well. The temperature sensor 158 can be integrated in the heating device 129. Alternatively it can be mounted on the texturing apparatus as an independent component. The heating device 129 can be thermally coupled to the housing 123 through a physical contact. The physical contact can be a direct physical contact between these components, or it can be an indirect physical contact through one or more intermediate solid media such as a heat-conducting paste. For instance, the heating device 129 can be affixed to an external wall of the housing, wherein as option the paste for facilitating thermal conductivity between the heating device and the housing can be used. The heating device 129 can be implemented as a sleeve surrounding/circumventing the housing.

[0141] The heat transferred to the housing 123 by the heating device 129 or the heat generated in the housing 123 by the heating device 129 can be transferred further to the other components of the texturing apparatus such as: the yarn channel 126, the inlet port 124, and the expansion chamber 147 via thermal coupling between these components. The thermal coupling between these components can be provided through physical contact, which can be a direct or indirect physical contact as explained above. For instance, the thermal coupling can be provided by mechanical clamping of these components to each other, by screwing and/or riveting of these components to each other, by using the heat-conducting paste between these components, by welding these components to each other, or by gluing of these components to each other, etc.

[0142] Fig. 6 depicts further options for installing heating devices and temperature sensors. The following optional pairs of heating devices and temperature sensors can be used in the same way as the heating device 129 and the temperature sensor 158: a heating device 132 configured to heat the yarn channel 126 though physical contact to it or by electromagnetic induction and a temperature sensor 144 integrated into the heating device 132 or configured to sense a temperature of the yarn channel; a heating device 134 configured to heat the downstream outlet 172 of the expansion chamber 147 though physical contact or by electromagnetic induction and a temperature sensor 141 integrated into the heating device 134 or configured to sense the temperature of the downstream section 172 of the expansion chamber 147. The heating devices 129,132, and134 can be implemented as electrical resistive heaters. They can be in direct physical contact with the respective components, or a solid medium (e.g. heat-conducting paste) can be used between the heating device and the respective component. The heating device 134 is configured such, that it does not block the fluid exhaust means of the expansion chamber 147 (e.g., the porous sidewall of at least the section of the expansion chamber).

[0143] Several pairs of the heating devices and the their temperature sensors can be used in parallel for providing advanced (high precision) temperature control of the texturing apparatus. The heating device 129 and the temperature sensor 158 can be used in conjunction with the controller 70 as described above. Each of the heating devices 132- and 134 and the respective temperature sensors 144 and 141 can be used in conjunction with a controller configured in the same way as the controller 70. Alternatively the controller 70 can be configured to control each of the heating devices 129, 132, and134 using the respective temperature sensor 158, 144, and 141. In this case each of the components has its own control loop and its temperature can be held at the desired temperature more accurately. For instance, the controller(s) controlling any of the heating devices 129, 132, and 134 can be configured to control the respective heating device such that the temperature of the respective component is held at the desired temperature within a tolerance interval of 2%, preferably 1%, more preferably 0.5 %.

[0144] The texturing apparatus 114 or the expansion chamber 147 may further comprise a fluid flow sensor 174 for registering a flow of the fluid egressing through at least a portion of the sidewall of the expansion chamber 147. The fluid flow sensor is communicatively coupled by a data bus or a computer network 183 to a controller 184 comprising a processor 185 and a memory 186 storing processor executable instructions. The controller 184 is operable to output a signal indicating that the registered flow is below a predefined value. The signal indicates that the pores of the side wall of expansion chamber 147 are clogged by debris generated by the texturing process and the expansion chamber has to be replaced by a new or a cleaned one.

[0145] Fig. 7b illustrates an expansion chamber 147e being a sintered part made of sintered granules 139 and/or fibers, wherein pores 113 between the granules and/or fibers constitute channels for egress of the fluid from the expansion chamber through its porous sidewall of a middle section 170 being adjacent to an inlet 171 and a downstream outlet 172. Such an expansion chamber can be manufactured by blending granules and/or fibers into a desired shape/mold 147f with or without compacting, and then heating the blended granules and/or fibers in a controlled atmosphere to bond the granules and/or fibers. The bottom section 171a of the shape/mold determines the shape of the inlet 171. The middle section 170c determines the shape of the middle section of the expansion chamber 147e. The upper section 172a determines the shape of the downstream outlet 172.

[0146] Granules, fibers, or powder particles of different sizes/grades can be used for manufacturing of different sections of the expansion chamber for producing those with different porosity and/or fluid permeability and/or degree of hardness, in particular shear strength. This can be made in one sintering step when granules, fibers, or powder particles having different sizes/grades are blended into the desired shape/mold before the sintering step. In addition the granules, fibers, or powder particles may be mixed with a bonding agent, which facilitates bonding between them produced in the sintering step.

[0147] As it is mentioned herein a material of the inlet 171 of the expansion chamber can have higher degree of hardness than a material of the porous sidewall of the section 170. This can be achieved by filling a bottom section 171a of shape/mold 170c with small granules or a mixture of the small granules and big granules and filling the other sections 170a and 172a with the big metal granules. As a result thereof the inlet 171 of the sinter part 147e is made solid or has lower porosity than the rest of the sinter part. The small granules and the big granules can be granules of different grades. In particular, when the sinter part 147e is made of metal granules, then the section 170 having the porous sidewall can be made of metal granules having an average weight being bigger than an average weight of metal granules out of which the inlet 171 is made. In case when the sinter part 147e is made of metal fibers, then the section 170 having the porous sidewall can be made of metal fibers having an average weight being bigger than an average weight of metal fibers out of which the inlet 171 is made. In case when the sinter part 147e is made of ceramic granules, then the section 170 having the porous sidewall can be made of ceramic granules having an average weight being bigger than an average weight of ceramic granules out of which the inlet 171 is made. In case when the sinter part 147e is made of a mixture of metal granules and metal fibers, then an average weight of metal granules of a mixture out which the section 170 having the porous sidewall is made can be bigger than an average weight of metal granules of a mixture out of which the inlet 171 is made and/or an average weight of metal fibers of the mixture out which the section 170 having the porous sidewall is made can be bigger than an average weight of metal fibers of the mixture out of which the inlet 171 is made. Further technologies can be employed for manufacturing of porous expansion chambers. For instance, an entire expansion chamber or its section or a layer of its section can be made porous by manufacturing the respective component as a foam molded part. Foam materials, in particular foam metals, are produced using different methods. One of the methods employs gas which is perfused through a melt, in particular a molten metal, while the melt is slowly cooled, such that solid foam is obtained. This can be achieved by using an impeller or a propellant. Another method is based on utilization of a porous place-holder scaffold inserted inside a mold. A melt is poured into the mold having place-holder scaffold placed therein and then cooled. Afterwards, the place-holder scaffold is removed. It is also possible to mix a not fusible material with the melt, cast the mixture and remove the not fusible material after the melt has solidified. Ceramic castings may be prepared by pouring ceramic slurry into a mold with a place-holder scaffold, drying the cast and sintering the obtained mass, whereby the place-holder scaffold is destroyed by thermal decomposition.

[0148] As another alternative, an entire expansion chamber or its section or a layer of its section can be made porous by manufacturing the respective component using a mesh cloth. Steel wire mesh cloths are stable enough to withstand mechanical stress, particularly when multiple cloths are packed and then combined to form a tubular form. Cloths with different mesh aperture may also have a pore-like structure, comparable to sinter-metal bodies.

[0149] Fig. 8 illustrates a step-up for evaluation of fluid permeability through sidewalls of various sections of an expansion chamber. The expansion chamber 147b is used in this drawing as non-limiting illustrative example. The set-up comprises a fluid (e.g. air) compressor 166a having compressed fluid outlet connected to a fluid flow regulator 179a for regulating fluid flow injected into the expansion chamber 147b. The fluid can be injected via a fluid gas pipe 161a connected to the inlet opening 182 of the expansion chamber via adaptor 210b and to the downstream outlet opening 181 of expansion chamber via adaptor 210a. An optional fluid heating device 165a can be installed in between the flow regulator 179a and adaptors 210a, b for heating the fluid injected into the expansion chamber. The adaptors are arranged such that fluid injected into the expansion chamber egresses only via one or more porous sidewalls of the expansion chamber. Adaptor 210 has a feed-through of a fluid gas pipe line 161b of a pressure gauge 211 for measuring pressure P1 inside the expansion chamber. Fluid impermeable shields can be employed for restricting fluid egress through a particular portion of the expansion chamber. In the example depicted in Fig. 8, the shields 187 cover the inlet 171 and the downstream outlet 172 of the expansion chamber 147b such that the fluid egresses only through the porous sidewall of the expansion chamber of the middle section 170. The fluid heating device 165a can be configured such that the fluid permeability is measured using the fluid having a temperature which is required for the texturing process (i.e. the desired temperature). The fluid permeability of the side wall of a particular portion of the expansion chamber cam be evaluated by registering a pressure difference/drop P1-P0 between an interior 188 and an exterior 189 of the expansion chamber for a given fluid (e.g. air) flow rate having a predefined temperature. The flow rate can be determined by the fluid flow regulator 179a. The fluid temperature can be determined by the fluid heating device 165a. The pressure P1 in the interior of the expansion chamber (i.e. pressure inside the expansion chamber) can be registered by the pressure gauge 211. The pressure P0 in the exterior of the expansion chamber (i.e. pressure outside the expansion chamber) is an atmospheric pressure, .e. g. a pressure of 101325 Pascals. The pressure drop at the specified/predefined flow rate of the fluid having the specified/predefined flow rate can be a characteristic of the fluid permeability of a side wall of a particular section of the expansion chamber or a sidewall of entire expansion chamber. When a pressure drop for a sidewall of one section of the expansion chamber is less than a pressure drop for a sidewall of another section the expansion chamber for the same fluid flow rate and the same fluid temperature then the sidewall of said section has higher fluid permeability than the side wall of the other section. The same is valid for fluid permeability of entire sidewalls of different expansion chambers. The registered values of pressure drop, fluid flow rate, and fluid temperature can be used for evaluation of the aforementioned viscous permeability coefficient and/or the aforementioned inertia permeability coefficient.

[0150] Local fluid permeability can be evaluated using the set-up depicted on Fig. 8 as well. In order to evaluate fluid permeability of a particular fragment of a sidewall of the expansion chamber, fluid impermeable shields have to be used in order to make the rest the sidewall of the expansion chamber (and if necessary all other sidewalls of the expansion chamber) fluid impermeable. The rest of the procedure is the same as for evaluation of the fluid permeability of the side wall of the section of the expansion chamber as described above. A pressure drop at a specified/predefined flow rate of the fluid having a specified/predefined flow rate can be a characteristic of the fluid permeability of the particular fragment of the sidewall of the expansion chamber, wherein these values can be used for evaluation of the aforementioned viscous permeability coefficient and/or the aforementioned inertia permeability coefficient. Uniformity of a fluid permeability of a sidewall of a section of an expansion chamber can be performed by registering the aforementioned parameters of the fluid flow for different fragments of the sidewall of the section of the expansion chamber, wherein each of the fragments has the same thickness and the same area of an interior surface being a fragment of an interior surface of the sidewall.

[0151] Fig. 9 illustrates a photo of a textured artificial turf yarn filaments. The left bundle 212 of the artificial turf yarn filaments is manufactured using the texturing apparatus equipped with the expansion chamber 147a-e disclosed herein. The right bundle 213 of the artificial turf yarn filaments is manufactured using the state of art texturing apparatus as disclosed in the referenced above chapter of the book "Synthetic fibers". As clearly seen from the Fig. 9 the filaments of the left bundle 212 have more twists 157 and more pronounced kinks 180 than the filaments of the right bundle 213.

[0152] Preferably, two technological factors have to be maintained constant throughout the texturizing process: (1) the thermal budget of the texturizing process (i.e. energy transferred to the yarn) has to be kept constant in order to avoid changes in the filament temperature in the texturing apparatus, because this temperature determines softening and plasticizing of the yarn; and (2) a stable crimping force must be applied to the yarn in the expansion chamber of the texturing apparatus. In addition, when a bundle of yarn is successfully texturized, it must be carefully cooled without exerting a stretching force.

[0153] The first technological factor can be stabilized by minimization of the heat transfer in the texturing apparatus between the yarn and the fluid and minimization of the heat transfer between the fluid and the texturing apparatus. The heat transfer between the texturing apparatus and the yarn can be neglected because its contribution in comparison with the heat transfer between the yarn and the fluid is much less. This can be achieved by configuring the controllers 152, 70, and 162 such that the yarn at the inlet port 124 of the texturing apparatus 114, the fluid in the texturing apparatus, and the texturing apparatus 114 itself are held at the same temperature required for the texturing process (the desired temperature). Since the heating of the texturing apparatus is mainly provided by at least one of the heating devices 129, 132-134, wherein the heating includes variation of heating power in order to compensate for the changes in the heat loss of the texturing apparatus (e.g. due to changes in environment surrounding the texturing apparatus), the changes in the temperature of the fluid are minimized, because both the texturing apparatus and the fluid provided in the texturing apparatus are held at the same temperature. As a result thereof the heat transfer between the texturing apparatus and the fluid and the heat transfer between the fluid and the yarn are minimized. When none of the heating devices is used, the heat transfer between the fluid and the texturing apparatus is the major factor determining the temperature of the texturing apparatus, wherein changes in the heat loss of the texturing apparatus cause substantial changes in the heat transfer between the fluid and the texturing apparatus and as a result thereof the heat transfer between the yarn and the fluid is also substantially changed. This may result in poor texturing properties of the yarn (e.g. shape of the textured filaments and/or mechanical properties of the textured filaments) and/or variation in the degree of texturing and/or crimp characteristics of the textured yarn over its length.

[0154] The first technological factor can be further stabilized by preheating the yarn before it enters the inlet port 124 such that it has a temperature of the texturing process immediately before it enters the inlet port 124. Since the yarn is cooled during transportation from the heating device 117 (e.g. godet) to the texturing apparatus 114 (distance 156 on Fig. 1), the heating device 150 has to be held at a temperature above the temperature of the texturing process, i.e. a temperature offset with respect to the temperature of the texturing process is needed. Depending on the distance between the heating device and the inlet port of the texturing apparatus and the environment temperature, the temperature offset can be 0.05 to 0.5 °C. The value of the temperature offset can be calculated by Newton's law of cooling T(t) = T_env + (T₀ - T_env) e^-rt, wherein T(t) is the temperature at time t, T_env is the temperature of the surrounding environment, T₀ is the initial temperature of the yarn, and r is the cooling coefficient of the yarn. The cooling coefficient can be determined by measuring a cooling curve of the yarn in a test set-up comprising a temperature sensor configured to sense the temperature of the yarn or a polymeric sample made of the same material as the yarn (e. g. a thermocouple) and a recorder system configured to register the temperature T(t) via the temperature sensor versus time t in a process of cooling the yarn or the polymeric sample from a preselected temperature to the temperature of the environment (e.g. a room temperature). A slope of the T(t) curve on a logarithmic scale is the cooling coefficient r of the cooling curve. The cooling coefficient r of different polyethylene blend compositions determined using this approach is equal to a value of 0.0134 1/s. This comparably small value for the cooling coefficient can be addressed to exothermic crystallization processes in the polymer on cooling.

[0155] Using the experimentally determined cooling coefficient the following temperatures of the yarn at the inlet port of the texturing apparatus are determined for the following example process parameters: the yarn speed of 160 m/min, the distance between the heating device and the inlet port of the texturing apparatus 0.2 m, and the temperature of the heating element 90 degree Celsius. The temperature of the yarn at the inlet port is 89.93 degree Celsius, when the temperature of the environment is 15 degree Celsius. The temperature of the yarn at the inlet port is 89.94 degree Celsius , when the temperature of the environment is 25 degree Celsius. The temperature of the yarn at the inlet port is 89.95 degree Celsius, when the temperature of the environment is 35 degree Celsius. The elapsed time from a point in time when the yarn is detached from a surface of the heating device, to a point in time when the yarn enters the inlet port, is calculated by dividing the distance by the yarn speed.

[0156] The first technological factor can be further stabilized by minimization of the distance 156 between the heating device 150 of the heating device and the inlet port 124 of the texturing apparatus 114. The distance can be less than 0.1 m, preferably less than 0.04 m.

[0157] The second technological factor can be stabilized by providing a stable gas-dynamic properties of the fluid flow in the texturing apparatus, in particular in the expansion chamber 147, 147a-d of the texturing apparatus. When the fluid enters the expansion chamber of the texturing apparatus, its flow velocity, pressure, density and temperature change. The expansion chamber functions as a diffuser, i.e. it decelerates the flow velocity of the fluid. The yarn inside the expansion chamber are also decelerated and swirled around. The improvement of the second technological factor is achieved by utilization of the porous sidewall providing more homogenous egress of the fluid 135 from the expansion chamber and/or more homogenous gas-dynamic properties of the fluid in the expansion chamber in comparison with a configuration of an expansion chamber in which longitudinal exhaust slots in a sidewall of the expansion chamber are used as the exhaust means.

[0158] Frictional abrasion occurs by contact with the inner walls of the expansion chamber and/or by yarn filament to yarn filament contact. Thereby debris (e.g. a fine particulate matter) is generated. The particulate matter originates from the surface of the filaments and is transferred to the components of the texturing device by the exiting fluid flow. Shortly after the texturing process has started, there is no particulate matter observable on the texturing apparatus, but, after a period of time, the particulate matter appears on the texturing apparatus (in particular on the inner and outer walls of the expansion chamber). Initially It can build up a layer of a few micrometres. The layer gets thicker with time and extends also to the housing the texturing apparatus. Building of this layer can compromise the performance of the texturing apparatus. First, it can affect thermal exchange with the environment and as a consequence change the temperature of the at least some components of the texturing apparatus such as the expansion chamber. This influence can be compensated at least partially by utilization of one or more heating devices 129, 132-134 as described above. Second, the building of the layer can change the performance of the expansion chamber such that the gas dynamic parameters of the fluid flow therein are changed, e.g. the layer can change the performance of the fluid exhaust means in the expansion chamber. For instance it can at least partially clog the pores of the side wall. As a result thereof the fluid flow in the expansion chamber can change and the crimping force can differ after the building of the layer. This problem can be remedied by utilization of the fluid flow sensor 174, which outputs the signal indicating that the fluid flow is below the predefined value.

[0159] An example of a successfully tested texturing apparatus is described herein as follows. The texturing apparatus has an overall length of 0.3 m without a guide tube. A yarn channel with a screwed in inlet port (infeed valve) has a length of 0.155 m and an expansion chamber has a length of 0.14 m. An outer diameter of the texturing apparatus is 0.022 m. Heated pressurized air is used as a fluid. The air temperature is set to 100 degrees Celsius. The pressure is set to 600000 Pa. The fluid flow is adjusted to 1.67 l/s. A polymer blend is prepared from LLDPE with a density of 917 g/l and HDPE with a density of 955 g/l and a master-batch with a density of 940 g/l. The polymer blend is extruded, spun to 144 filaments, drawn to a ratio of 1:5.6 and conducted to the texturing machines. 6 yarn filaments with a breadth of 1 mm and a thickness of 0.1 mm are fed into one of the texturing apparatuses. The feeding godets are located 200 mm above the respective texturing apparatuses. The feeding godets are heated to a temperature slightly higher than 90 degrees Celsius, i. e. 90.1 to 90.2 degrees Celsius, in accordance with the approach described above, wherein an environment temperature is 25 °C and an experimentally determined cooling coefficient r is 0.0134 1/s, and a yarn speed is 170 m/min. With these settings the yarn filaments are at a temperature of 90 degrees Celsius when they enter the texturing apparatuses.

[0160] The textured monofilament yarn, which can be used as the artificial turf fibers can be prepared from a polymer blend comprising at least two polymers. The polymer blend can be a more complex mixture. The polymer blend can be at least a three phase system. It can comprise a first polymer, a second polymer, and a compatibilizer. These components form a three-phase system. The first and a second polymer are immiscible. If there are additional polymers or compatibilizers are used in the polymer blend, then the three phase system may be increased to a four, five or more phase system. The first polymer could be polyamide and the second polymer could be polyethylene. The polymer blend can comprise a polar polymer and a non-polar polymer. The polymer blend can comprise at least one of the following: polyethylene terephthalate, which is also commonly abbreviated as PET, polybutylene terephthalate, which is also commonly abbreviated as PBT, polyethylene, polypropylene.

[0161] The compatibilizer can be any one of the following: a maleic acid grafted on polyethylene or polyamide; a maleic anhydride grafted on free radical initiated graft copolymer of polyethylene, SEBS, EVA, EPD, or polyproplene with an unsaturated acid or its anhydride such as maleic acid, glycidyl methacrylate, ricinoloxazoline maleinate; a graft copolymer of SEBS with glycidyl methacrylate, a graft copolymer of EVA with mercaptoacetic acid and maleic anhydride; a graft copolymer of EPDM with maleic anhydride; a graft copolymer of polypropylene with maleic anhydride; a polyolefin-graft-polyamide; and a polyacrylic acid type compatibilizer.

[0162] For instance, the textured monofilament yarn, which can be used as the artificial turf fibers can be prepared from polyethylene based polymers. Different polyethylene (type) based polymers are blended such that a desired property profile is created. The main focus hereby lies on the crimp properties of the monofilament yarn.

[0163] The polymer blend can comprise LLDPE and HDPE. LLDPE is a copolymer of ethylene and α-olefin or 1-olefin. Several 1-olefins can be copolymerized together with ethylene, but most of the commercially available LLDPEs are copolymers with 1-butene, 1-hexene or 1-octene, or mixtures thereof, as co-monomers. In a polymerization process, both the monomer ethylene and the co-monomer 1-olefin are incorporated step-by-step into a growing macromolecular chain. In each single step either an ethylene molecule or a 1-olefin molecule is added to the chain.

[0164] The sequence of ethylene and 1-olefin units along the chain is determined by both, the polymerization catalysts and the details of the reaction layout, such as pressure, temperature, etc. In general, there are two distinctive types of catalysts; multi-site catalysts and single-site catalysts. The type of catalyst controls the polymerization progress and the way in which monomers and co-monomers are added to the polymer chain. Polymers are always entities of macromolecules with different chain length, distributed around an average value. Polymers are thus characterized by a molecular weight distribution. Different average values can be defined depending on statistical methods. In practice two averages are used, denoted as M_n and M_W. M_n is the number average of the molecular weight distribution, mathematically expressed by

[0165] MW is the weight average of the molecular weight distribution and is related to the fact that heavier molecules contribute more to the arithmetic average than the lighter ones. This is mathematically expressed by

[0166] The polydispersity index PDI is the ratio of M_W / M_n and indicates the broadness of the distribution. In general, polymers prepared with multi-site catalysts have a greater PDI than those prepared with single-site catalysts.

[0167] Moreover, the chemical composition of the macromolecules depends on the type of catalyst. As mentioned above, every 1-olefin or α-olefin can act as a co-monomer in the polymerization process, but typically only 1-butene, 1-hexene and 1-octene is in use for copolymerization of LLDPE. As these molecules carry a double bond between two carbon atoms, it is possible to insert them instead of an ethylene molecule into the growing chain of the macromolecule which forms in the polymerization process. The incorporation of a 1-olefin molecule into the polymer main chain leaves, other than ethylene does, a side chain on the main chain.1-butene, for instance, includes 4 carbon atoms and generates an ethyl side chain, whereas two carbon atoms (the two with the double bond between carbon atoms 1 and 2) are incorporated into the main chain and another two carbon atoms extent outwardly of that main chain as a side chain. In case of 1-hexene the length of the side chain is 4 carbon atoms and it is 6 with 1-octene. Concerning the side chain distribution, the molecular architecture may greatly be influenced by the choice of the catalyst used in the polymerization process. Multi-site catalysts, also referred to as Ziegler or Ziegler-Natta catalysts or Phillips catalysts, yield in heterogeneously branched polymers, whereas single-site catalysts, also referred to as metallocene catalysts, yield in homogeneously branched polymers. In heterogeneously branched macromolecules the distance from one branching point to another branching point is broadly distributed along the polymer main chain. The other way round, the branches are more evenly spaced in homogeneous branched LLDPEs. It has also been observed that with Ziegler catalysts the co-monomers are preferably incorporated into the short length main chains, while the longer main chains deplete of co-monomers. Depending on the design of the polymerization process the side chain branching is heterogeneous or homogeneous.

[0168] The use of multi-site catalysts results in polymers with relatively broad molecular weight distributions compared with single-site catalysts. Moreover, the molecular weight distribution can be influenced by using a cascaded reactor layout, leading to polymers with multimodal molecular weight distributions. Blending different types of polyethylene in situ, i. e. inside the polymerization reactor, or ex situ, i. e. after polymerization, broadens the variety further.

[0169] Number, length and distribution of the side chains in PE macromolecules greatly influence the properties and the processability. According to applicant's experience, it is advantageous to use LLDPE with a broad distribution of side chains, typical for Ziegler-catalyzed, solution polymerized polymers for turf fiber production, in particular for texturized turf fiber production. The fraction of short length polymer chains with high branching makes the fibers, produced of these LLDPE-types, easy to texturize. In the course of the texturizing process the fibers need to be softened under the influence of heat and then deformed, such that a wanted crimped shape results and stays on the fibers. It has turned out that the above mentioned LLDPE-types are appropriate for this process.

[0170] Preferably, in the texturing process only a certain portion of a crystalline fraction of the polymeric yarn is in a molten state, i. e. the small crystallites of the structure have lost their ordered state, whereas another fraction has not. This means, that the polymeric yarn ought to be stable enough not to adhere or lump and deformable enough to crimp under the impact of heat and mechanical deformation. Once the deformation is achieved, the polymeric yarn is quenched giving rise to crystallization of the small crystallites. Thereby the texturizing stays in the yarn.

[0171] Texturizing is supported by both, the chemical structure of the polymeric yarn and the temperature of the yarn at the moment of deformation. Both can be appraised by knowledge of the melting behavior of the polymeric yarn. The melting behavior manifests in a characteristic melting graph detected by DSC. In a characteristic melting graph, measured by DSC, the variation of the melt enthalpy (heat flow) over time, i. e. dH/dt is plotted against the variation in temperature over time, i. e. dT/dt. The melt enthalpy ΔH or heat of fusion can be calculated by mathematical integration, i. e. the determination of the area between the baseline and the complete curve or parts thereof. This reflects the amount of heat necessary to completely or partially melt the sample.

[0172] Polymers herein are generally of the type of partially crystalline substances. Partially crystalline polymers are characterized in that a part thereof is solid crystals, while the rest is amorphous. The amorphous part behaves as a highly viscous liquid. Liquid parts of a polymer sample do not contribute to the melting process. The melting curve as detected by DSC reflects the melting behavior of the crystallites.

[0173] Number and size of the crystallites determine the density of polymers. LLDPE has a lower density compared with HDPE. Combining LLDPE and HDPE into a blend may have the advantage to broaden the melting curve. The melting curves of LLDPE are quite specifiable, depending on what type of LLDPE is regarded. As already mentioned, the co-monomer, the catalyst and the type of process layout have a great influence on the appearance of the melting curve. There are three types of processes for the preparation of LLDPE: slurry, solution and gas-phase. The slurry-process is underrepresented in this context, as very few LLDPE-types exist. But, it is the method of choice of the production of HDPE. LLDPE from solution processes is characterized in that mostly 1-octene acts as co-monomer in that process. Contrariwise 1-hexene and 1-butene are the co-monomers used in gas-phase processes.

[0174] The composition of an example polymeric blend used for manufacturing of the textured monofilament yarn comprises:

(A) 10 % by weight of the total composition to 95 % by weight of the total composition of at least one LLDPE having

• a density of 915 to 920 grams per liter,
• a melt index (I₂) from 1 to 10 grams per 10 minutes,
• a polydispersity M_W/M_n in a range of 3 - 5, in particular,
• 1-olefin comonomers, the comonomers being 1-butene, 1-hexene or 1-octene or compositions thereof,
• a heterogeneously or homogeneously side branching distribution,
• a melting graph as measured by DSC with one, two or three maxima in the temperature range between 30 °C and 150 °C, wherein the number of maxima is determined by a number of polymorphic modifications of the LLDPE used in this example polymeric blend, the maxima can be isothermal, overlapping, or co-located; and

(B) 10 % by weight of the total composition to 30 % by weight of the total composition of at least one HDPE having

• a density of 935 to 960 grams per liter,
• a melt index (I₂) from 1 to 10 grams per 10 minutes,
• a polydispersity index M_W/M_n in a range of 3 - 6, in particular,
• 1-olefin comonomers, the comonomers being 1-butene, 1-hexene or 1-octene or compositions thereof,
• a heterogeneously side branching distribution,
• a melting graph as measured by DSC with one maximum in the temperature range between 30 °C and 150 °C.

[0175] Fig. 10 illustrates a flowchart diagram of a method for manufacturing of a textured yarn. The method begins with process block 190, wherein the yarn is manufactured and the heating device 129 and/or the heating device 132 heat the texturing apparatus, wherein the first controller is configured to control the heating device(s) 129 and/or 132 such that the temperature of the texturing apparatus is held at the desired temperature and the second controller is configured such that the fluid under pressure injected into the texturing apparatus has the desired temperature as well. The yarn can be manufactured using the devices depicted in Fig. 1. Process block 192 is executed after process block 190. In process block 192 a texturing of the manufactured yarn is performed in the texturing apparatus. The texturing comprises the following: injecting the fluid under pressure into the texturing apparatus via the fluid inlet; injecting a yarn into the texturing apparatus via the yarn inlet port of the texturing apparatus; and subjecting, inside the gas-dynamic yarn texturing expansion chamber 147, 147a-d, the flowing yarn to a turbulent flow of the fluid so that the texturing of the flowing yarn occurs. Process block 194 is executed after process block 192. Execution of process block 194 causes interruption of execution of process block 192 and as option of process block 190, i.e. when necessary process block 190 can be executed in parallel with process block 190. Process block 194 can be a procedure (or a texturing apparatus maintenance procedure) which is executed at predefined or varying time intervals, in particular when at least one of the following criteria is complied with: a) a flow of the fluid egressing through at least a portion of the sidewall is below a predefined value; b) the texturing of the yarn is performed for a predefined time interval; and c) a predefined length of the yarn is textured by performing the texturing of the yarn. The flow of the fluid egressing through at least a portion of the sidewall can be registered by the fluid flow sensor 174. The procedure comprises the following process blocks 196, 198, 200, and 202 when the execution of process block 190 is not interrupted. In process block 196 the texturing of the yarn is interrupted by terminating the injecting of the yarn being manufactured in process block 190 into the texturing apparatus and guiding the yarn being manufactured away from the texturing apparatus. Process block 198 is executed after process block 196. In process block 198 the gas-dynamic yarn texturing expansion chamber is substituted by another gas-dynamic yarn texturing expansion chamber in the texturing apparatus. Process block 200 is executed after process block 198. In process block 200 the injecting of the yarn being manufactured in process block 190 into the texturing apparatus. Process block 202 is executed after process block 200. In process block 202 the texturing of the yarn in the texturing apparatus is resumed when the temperature of the texturing apparatus is at the desired temperature. This condition is needed because the attachment of the other expansion chamber may cause a temporary decrease in a temperature of the texturing apparatus. In other words, it might take time before the first controller causes the temperature of the texturing apparatus to reach the desired temperature. In case when execution of process block 194 causes interruption of execution process blocks 190 and 192, the procedure comprises only process block 198. In this case process block 190 is executed after process block 194 and process block 192 is executed after process block 190 in order to resume texturing of the yarn. The expansion chamber detached from the texturing apparatus in process block 198 can be cleaned in order remove the debris from its pores. The cleaning procedure may be executed in a cleaning solvent using ultrasonic agitation. Fig. 11 illustrates a flowchart diagram of a method for manufacturing of a textured monofilament yarn, which can be used as a textured artificial turf yarn. The method can be executed using devices depicted in Fig. 1. The method begins with process block 600, wherein a monofilament yarn is provided. The monofilament yarn comprises a polymer blend of two or more polymers. As it is mentioned above the polymer blend can comprise immiscible polymers and at least one compatibilizer. Process block 602 is executed after 600. In process block 602 DSC data is received. The data comprises DSC data of a sample of the polymer blend measurement using a DSC system. The data characterizes melting process(es) of different polymers of the blend. The data can further characterize melting processes of different polymorphic modifications of one of the polymers of the blend, if said polymer has polymorphic modifications. The sample can be a sample of the monofilament yarn. Alternatively the sample can be taken from the polymer blend used for manufacturing of the monofilament yarn.

[0176] Process block 604 is executed after process block 602. In process block 604 a melting temperature of at least one polymer of the monofilament is determined using the DSC data. Afterwards the desired temperature of the texturing process is determined using the one or more determined melting temperatures. The desired temperature is selected such that a portion of a crystalline fraction of the polymer blend is in a solid state at this temperature and another portion of the crystalline fraction of the polymer blend is in a molten state at this temperature. Process block 606 is executed after process block 604. In process block 606 the monofilament yarn is textured using the texturing device to provide the textured artificial yarn, the controller 70 is programmed to hold the actual temperature at the determined desired temperature. In particular, one or more of the following components of the texturing apparatus can be kept at determined desired temperature: the yarn channel, the housing, and the yarn inlet port. Process block 606 may comprise execution of the procedure of process block 194.

[0177] An optional process block 606a can be executed before process block 606, preferably immediately before process block 606. In process block 606a the temperature of the monofilament yarn is increased to a temperature which is higher than the temperature the texturing process using one or more heating devices (e.g. the heating godet 117). The offset of the temperature with respect to the temperature of the texturing process can be selected such, that the temperature of the filament yarn when it enters the texturing device 114 is equal or substantially similar to the temperature of the texturing process. The procedure for determination of the offset value is described above.

[0178] Another optional process block 608 can be executed after process block 606, preferably immediately after process block 606. In process block 608, the textured monofilament yarn is cooled. The cooling can be performed using a cooling godet 120. The cooling can be a quenching procedure, wherein the textured monofilament yarn can be cooled down to a temperature within 1-5 seconds. This temperature is below a temperature at which entire crystalline fraction of a polymer or polymer blend of the yarn is in a solid state.

[0179] Fig. 12 illustrates a flow chart diagram of a method for manufacturing of a monofilament yarn, which can be used in the methods which flow chart is shown in Figs. 10 and 11. The method begins with process block 620. In process block 620 the polymer blend is created. The polymer blend can comprise two different types of polyethylene (e.g. LLDPE and HDPE). The polymer blend can be a more complex system. For instance it can be at least a three-phase system. In this case it can comprise a first polymer, a second polymer and a compatibilizer. The first polymer and the second polymer are immiscible. In other examples there may be additional polymers such as a third, fourth, or even fifth polymer that are also immiscible with the second polymer. There also may be additional compatibilizers which are used either in combination with the first polymer or the additional third, fourth, or fifth polymer. The first polymer forms polymer beads surrounded by the compatibilizer. The polymer beads may also be formed by additional polymers which are not miscible in the second polymer. The polymer beads are surrounded by the compatibilizer and are within the second polymer or mixed into the second polymer.

[0180] Process block 622 is executed after process block 620. In process block 622 the polymer blend is extruded into a monofilament yarn. This extrusion can be performed using the extruder 100 depicted in Fig. 1. The polymer blend is fed into the extruder 100 via inlet 101. Inside the extruder100 the polymers of the polymer blend are completely molten and the individual parts of the blend are homogeneously mixed. The polymer melt is pressed through a spinneret (or a wide slit nozzle followed by a cutter) 102, 102a, whereby filaments of a specific shape are formed.

[0181] Process block 624 is executed after process block 622. The filaments are (rapidly) cooled down to a temperature where crystallization can take place. In the crystallization process the crystallites are forming to a percentage, which depends on the cooling rate. The higher the cooling rate, the less is the crystallinity and vice versa. Process block 624 can be executed using the cooling device 97 depicted in Fig. 1.

[0182] Process block 626 is executed after process block 624. In process block 626 the monofilament yarn is drawn e.g. to a factor of 4 - 6, i.e. the monofilament yarn is elongated 4-6 times. The preferred drawing ratio is 1:5.6. During the drawing process the monofilament yarn is heated to a temperature. The temperature can be at least 10-20 degrees Celsius (preferably 70-100 degrees Celsius for a polymer blend comprising Polyamide (PA) and/or Polyethylene (PET)) below the temperature of the last maximum on the DSC curve of the polymer blend used for the manufacturing of the monofilament yarn drawn in process block 626. The temperature of the last maximum on the DSC curve is the temperature being the last in the sequence determined in process block 604. Process block 626 can be executed using the drawing device 115 or 115a. The drawing of the monofilament yarn forces the macromolecules to parallelize. This results in a higher degree of crystallinity and increased tensile strength after cooling, compared with undrawn filaments. In addition the drawing process can reshape the polymer beads such that the reshaped beads have thread-like regions.

[0183] Process block 628 is executed after process block 626. In process block 628 the monofilament yarn is cooled again. This can be done in the same way as in process block 624. The cooling godet or cooling drum 116 can be used for performing the cooling in process block 628.

[0184] Process block 630 is executed after process block 628. In process block 630 the monofilament yarn is drawn e.g. to a factor of 1.1 -1.3. The preferable drawing ratio is 1:1.2. During the drawing process the monofilament yarn is heated to a temperature. The temperature can be the same as in Process block 626. Process block 630 can be executed using the drawing device 118. Execution of process block 630 can result in relaxation of stress in the monofilament yarn.

[0185] Fig. 13 shows a flowchart which illustrates one method of creating the polymer blend which can be used for manufacturing of the monofilament yarn, e.g. according to the method which flow chart is shown in Fig. 12. In other the other words, the method which flow chart is shown in Fig. 13 can be an extension or alternative of process block 620. In this example the polymer mixture is a three-phase system and comprises the first polymer, a second polymer and the compatibilizer. The polymer blend may also comprise other components such as additives to color or provide flame or UV-resistance or improve the flowing properties of the polymer blend. First in step 640 a first blend is formed by mixing the first polymer with the compatibilizer. Additional additives may also be added during this step. Next in step 642 the first blend is heated. Next in step 644 the first blend is extruded. Then in step 646 the extruded first blend is then granulated or chopped into small pieces. Next in step 648 the granulated first blend is mixed with the second polymer. Additional additives may also be added to the polymer blend at this time. Finally in step 650 the granulated first blend is heated with the second polymer to form the polymer blend. The heating and mixing may occur at the same time. The polymer blend created in process block 650 can be further processed in the same way as the polymer blend created in process block 620.

[0186] Fig. 14 shows a flowchart which illustrates a further example of how to create a polymer blend for manufacturing of the monofilament yarn, e.g. according to the method which flow chart is shown in Fig. 12. In other words, the method which flow chart is shown in Fig. 14 can be an extension or alternative of process block 620. In this example the polymer blend additionally comprises at least a third polymer. The third polymer is immiscible with the second polymer and the polymer blend is at least a four-phase system. The third polymer further forms the polymer beads surrounded by the compatibilizer with the second polymer. First in step 660 a first blend is formed by mixing the first polymer and the third polymer with the compatibilizer. Additional additives may be added to the first blend at this point. Next in step 662 the first blend is heated. The heating and the mixing of the first blend may be done at the same time. Next in step 664 the first blend is extruded. Next in step 666 the extruded first blend is granulated or chopped into tiny pieces. Next in step 668 the first blend is mixed with the second polymer. Additional additives may be added to the polymer blend at this time. Then finally in step 670 the heated first blend and the second polymer are heated to form the polymer blend. The heating and the mixing may be done simultaneously. The polymer blend created in process block 670 can be further processed in the same way as the polymer blend created in process block 620.

[0187] Fig. 15 shows a diagram which illustrates a cross-section of a polymer blend 400. The polymer blend 400 comprises a first polymer 402, a second polymer 404, and a compatibilizer 406. The first polymer 402 and the second polymer 404 are immiscible. The first polymer 402 is less abundant than the second polymer 404. The first polymer 402 is shown as being surrounded by compatibilizer 406 and being dispersed within the second polymer 404. The first polymer 402 surrounded by the compatibilizer 406 forms a number of polymer beads 408. The polymer beads 408 may be spherical or oval in shape or they may also be irregularly-shaped depending up on how well the polymer blend is mixed and the temperature. The polymer blend 400 is an example of a three-phase system. The three phases are the regions of the first polymer 402. The second phase region is the compatibilizer 406 and the third phase region is the second polymer 404. The compatibilizer 406 separates the first polymer 402 from the second polymer 406.

[0188] Fig. 16 shows a further example of a polymer blend 500. The example shown in Fig. 16 is similar to that shown in Fig. 15 however, the polymer mixture 500 additionally comprises a third polymer 502. Some of the polymer beads 408 are now comprised of the third polymer 502. The polymer blend 500 shown in Fig. 14 is a four-phase system. The four phases are made up of the first polymer 402, the second polymer 404, the third polymer 502, and the compatibilizer 406. The first polymer 402 and the third polymer 502 are not miscible with the second polymer 404. The compatibilizer 406 separates the first polymer 402 from the second polymer 404 and the third polymer 502 from the second polymer 404. In this example the same compatibilizer 406 is used for both the first polymer 402 and the third polymer 502. In other examples a different compatibilizer 406 could be used for the first polymer 402 and the third polymer 502.

[0189] The third of the first polymer can be a polar polymer. The third of the first polymer can be for instance polyamide. Alternatively the third or the first polymer can be polyethylene terephthalate or polybutylene terephthalate.

[0190] The polymer blend can comprise between 1% and 30% by weight the first polymer and the third polymer combined. In this example the balance of the weight may be made up by such components as the second polymer, the compatibilizer, and any other additional additives put into the polymer mixture.

[0191] Alternatively the polymer blend can comprise between 1 and 20% (or between 5% and 10%) by weight of the first polymer and the third polymer combined. Again, in this example the balance of the weight of the polymer mixture may be made up by the second polymer, the compatibilizer, and any other additional additives.

[0192] The polymer blend can comprise between 1% and 30% by weight the first polymer. In this example the balance of the weight may be made up for example by the second polymer, the compatibilizer, and any other additional additives.

[0193] Alternatively the polymer blend can comprises between 1% and 20% (or between 5% and 10%) by weight of the first polymer. In this example the balance of the weight may be made up by the second polymer, the compatibilizer, and any other additional additives mixed into the polymer mixture.

[0194] The second polymer can be a non-polar polymer. The second polymer can be polyethylene or polypropylene. The polymer blend can comprise between 80-90% by weight of the second polymer. In this example the balance of the weight may be made up by the first polymer, possibly the second polymer if it is present in the polymer mixture, the compatibilizer, and any other chemicals or additives added to the polymer mixture.

[0195] The polymer blend can further comprise any one of the following: a wax, a dulling agent, a ultraviolet stabilizer, a flame retardant, an anti-oxidant, a pigment, and combinations thereof. These listed additional components may be added to the polymer blend to give the artificial turf fibers made of the textured monofilament yarn other desired properties such as being flame retardant, having a green color so that the artificial turf more closely resembles grass and greater stability in sunlight.

[0196] The thread-like regions can be embedded in the second polymer of the textured monofilament yarn. The textured monofilament yarn can comprise a compatibilizer surrounding each of the thread-like regions and separating the first polymer from the second polymer. The thread-like regions can have a diameter of less than 20 (or 10) micrometer. Alternatively the thread-like regions can have a diameter of between 1 and 3 micrometer. The thread-like regions can have a length of less than 2 mm in longitudinal direction of the monofilament yarn.

[0197] The textured monofilament fiber can be used as artificial turf fiber for manufacturing of an artificial turf. The textured monofilament fiber can be incorporated into an artificial turf backing of the artificial turf. This can be implemented for instance by tufting or weaving the artificial turf fiber (i.e. the textured monofilament yarn) into the artificial turf backing. After the incorporation of the artificial turf fibers a further optional process can be performed, wherein the artificial turf fibers are bound to the artificial turf backing. For instance the artificial turf fibers may be glued or held in place by a coating or other material. Alternatively a liquid backing (e.g. latex or polyurethane) can be applied on the backside of the artificial turf backing such that the liquid backing wets the lower portions of the fiber and firmly includes the fiber after the solidification of the backing and thus causing a sufficient tuft lock.

[0198] Fig. 17 shows an example of a cross-section of an example of artificial turf 146. The artificial turf 146 comprises an artificial turf backing 142. Artificial turf fiber 145 has been tufted into the artificial turf backing 142. A coating 143 is shown on the bottom of the artificial turf backing 142. The coating may serve to bind or secure the artificial turf fiber 145 to the artificial turf backing 142. The coating 143 may be optional. For example the artificial turf fibers 145 may be alternatively woven into the artificial turf backing 142. Various types of glues, coatings or adhesives could be used for the coating 143.

List of reference numerals

[0199] 

70

controller for controlling temperature of texturing apparatus 114

71

data bus connecting texturing apparatus 114 and controller 70

72

processor of controller 70

73

memory of controller 70

80

oven of drawing device 115a

81-83

feeding rollers of drawing device 115a

84-86

receiving rollers of drawing device 115a

95

hole in plate 102a of extruder outlet 102

96

polymer blend

97

cooling device

98, 99

rollers of cooling device 97, e.g. cooling godet

100

extruder

101

hopper

102

extruder outlet

102a

plate of extruder outlet 102

103-105

rollers of drawing device 115,

106, 107

rollers of cooling device 116, e.g. cooling godet

108, 109

rollers of heating device 117, e.g. heating godet

110-112

rollers of drawing device 118

113

pore in sidewall of expansion chamber 147d made of sintered metal granules

114

texturing apparatus

115

drawing device

115a

drawing device

116

cooling device, e.g. cooling godet

117

heating device, e.g. heating godet

118

drawing device

119

yarn or monofilament yarn

120

roller of cooling godet

121

roller for further processing

122

textured yarn, or textured monofilament yarn

123

housing of texturing apparatus 114

124

yarn inlet port of texturing apparatus 114

125

end portion (yarn inlet) of yarn channel 126

126

yarn channel

127

fluid channel for guiding fluid from the fluid inlet to the end portion (or yarn inlet) of yarn channel 126 via fluid channel 176

128

temperature sensor of fluid channel 127

129

heating device for heating of housing 123

130

fluid inlet of texturing apparatus 114

131

temperature sensor of fluid inlet 130

132

heating device for heating of yarn channel 126

133

thread of clamping mechanism

134

heating device for heating of a lower section of expansion chamber 147

135

a portion of fluid flow egressing through sidewall of expansion chamber 147

136

monofilament yarn before its processing in drawing device 115

137

second polymer

138

first polymer

139

metal granule in sidewall of expansion chamber 147d made of sintered metal granules

140

monofilament yarn before its processing in drawing device 140

141

temperature sensor of heating device 134 for heating of a downstream outlet 172 of expansion chamber 147

142

artificial turf backing

143

coating of artificial turf backing

144

temperature sensor of heating device 132 for heating of yarn channel 126

145

artificial turf fibers

146

artificial turf

147, 147a-d

expansion chamber

147e

expansion chamber made of sintered metal granules

147f

a mold for sintering of expansion chamber 147d

148

yarn guide tube

149

a portion of fluid flow egressing through downstream outlet of expansion chamber 147

150

heating device of roller 109 of heating godet 117

151

temperature sensor of roller 109

152

controller for controlling heating device 150

153

processor of controller 152

154

memory of controller 152

155

data bus connecting controller 152 and heating device 117

156

distance between heating device 117 and texturing apparatus

157

twisted yarn filament

158

temperature sensor of heating device 129 for heating of housing 123

159

conical shape of inlet port 124

160

screw of clamping mechanism

161, 161a,b

fluid pipe line

162

controller for controlling fluid heater 165 for fluid heating

163

processor of controller 162

164

memory of controller 162

165, 165a

fluid heating device

166, 166a

fluid compressor

167

data bus connecting controller 162, fluid heater 165, fluid flow meter 179, and temperature sensors 128 and/or 131

168a-d

layers of expansion chamber 147c

169

inner channel of expansion chamber 147a-d

170

section of expansion chamber 147a-c having porous sidewall permeable for fluid

170a, b

subsections of section of expansion chamber 147d having porous sidewall permeable for fluid

170c

sectionsof mold 147f for forming section 170 of expansion chamber 147e

171

inlet of expansion chamber 147a-e

171a

section of mold 147f for forming inlet 171 of expansion chamber 147e

172

downstream outlet of expansion chamber 147a-e

172a

section of mold 174f for forming downstream outlet of expansion chamber 147e

173

diameter of inner channel 169 of expansion chamber 147a, 147c, 147d; inlet opening diameter of inlet 171 of expansion chamber 147a-c; and outlet opening diameter of downstream outlet 172 of expansion chamber 147a-c

173a

outlet opening diameter of downstream outlet 172 of expansion chamber 147b

173b

inlet opening diameter of inlet 171 of expansion chamber 147b

174

fluid flow sensor for fluid flow 135 egressing through sidewall of expansion chamber 147

175

vortex zone of fluid flow in expansion chamber

176

fluid channel for infeed of the fluid into the yarn channel 126

177

threaded bushing of yarn inlet port 124

178

yarn channel of inlet port 124

179, 179a

fluid flow regulator

180

kinked/bent yarn filament

181

outlet opening of downstream outlet 172 of expansion chamber 147, 147a-c

182

inlet opening of inlet 171 of expansion chamber 147, 147a-c

183

data bus connecting controller 183 and fluid flow sensor 174

184

controller for controlling fluid flow sensor 174

185

processor of controller 184

186

memory of controller 184

187

shields for testing expansion chamber 147, 147a-c

188

interior of expansion chamber 147b

189

exterior of expansion chamber 147b

190, 192, 194, 196, 198, 200, 202

method steps

210a,b

adaptors for testing expansion chamber 147b

211

pressure gauge

212

artificial turf yarn manufactured using texturing apparatus equipped with expansion chamber 147, 147a-d

213

artificial turf yarn manufactured using texturing apparatus equipped with state of art expansion chamber

400

polymer blend

402

first polymer

404

second polymer

406

compatibilizer

408

polymer beads

500

polymer blend

502

third polymer

600, 602, 604, 606a, 606, 608

method steps

620, 622, 624, 626, 628, 630

method steps

640, 642, 644, 646, 648, 650

method steps

660, 662, 664, 666, 668, 670

method steps

Claims

1. A gas-dynamic yarn texturing expansion chamber (147; 147a-d), comprising:

• an inlet (171) for a fluid flow and a yarn flow;

• at least a section (170) having a sidewall being porous to provide egress of a portion (135) of the fluid flow from the expansion chamber; and

• a downstream outlet (172) for the yarn flow and another portion (149) of the fluid flow.

2. The gas-dynamic yarn texturing expansion chamber of claim 1, wherein the gas-dynamic yarn texturing expansion chamber is a porous sinter part (147e) made of:

metal granules (139);

metal fibers;

ceramic granules; and/or

a mixture of metal granules and metal fibers,

wherein the porosity is preferably bigger than 15% and/or preferably less than 60% when the sinter part is made of sintered metal granules, wherein the porosity is preferably bigger than 45% and/or preferably less than 90% when the sinter part is made of sintered metal fibers.

3. The gas-dynamic yarn texturing expansion chamber of claim 2, wherein the inlet (171) being formed by sintered granules and/or fibers that provide higher degree of hardness of the inlet than of the section (170), wherein the inlet being configured for forming a frictional or non-positive connection.

4. The gas-dynamic yarn texturing expansion chamber claim 2 or 3, wherein
in case when the sinter part is made of metal granules (139), then the section is made of metal granules having an average weight being bigger than an average weight of metal granules out of which the inlet is made;
in case when the sinter part is made of metal fibers, then the section is made of metal fibers having an average weight being bigger than an average weight of metal fibers out of which the inlet is made;
in case when the sinter part is made of ceramic granules, then the section is made of ceramic granules having an average weight being bigger than an average weight of ceramic granules out of which the inlet is made; and
in case when the sinter part is made of a mixture of metal granules and metal fibers, then an average weight of metal granules of a mixture out which the section is made is bigger than an average weight of metal granules of a mixture out of which the inlet is made and/or an average weight of metal fibers of the mixture out which the section is made is bigger than an average weight of metal fibers of the mixture out of which the inlet is made.

5. The gas-dynamic yarn texturing expansion chamber of claim 1, wherein the section is made of one of:

metal foam having a porosity preferably bigger than 85% and/or preferably less than 95%;

ceramic foam having a porosity preferably bigger than 85% and/or preferably less than 95%; and

porous plastic.

6. The gas-dynamic yarn texturing expansion chamber of any one of the preceding claims, comprising an inner channel (169) connecting an outlet opening (181) of the downstream outlet (172) and an inlet opening (182) of the inlet (171), wherein the inner channel (169) has a tapering in a direction from the downstream outlet (172) to the inlet (171), and/or
wherein an air permeability and/or a porosity of the sidewall increases in a direction from the inlet (171) to the downstream outlet (172), and/or
wherein a length of the inner channel (169) is at least 12 times, preferably at least 14 times, bigger than a diameter of the inlet opening (182); and/or
a diameter of the outlet opening (181) is at least 1.3 times bigger than the diameter of the inlet opening (182); and/or
wherein the sidewall comprises a first tubular layer (168a) and a second tubular layer (168c) circumventing the first tubular layer (168a) and the first tubular layer (168a) has a higher air permeability and/or porosity than the second tubular layer (168c); and/or
wherein the gas-dynamic yarn texturing expansion chamber is configured to perform the following when a fluid under pressure is injected into the inlet (171) via an opening having a diameter less than the diameter of the inlet opening (182):

operate as a diffuser for the fluid flow, and/or

cause generation of a vortex fluid flow layer (175) adjacent to a surface of the inner channel (169), wherein a thickness of the vortex fluid flow layer decreases in a direction from the inlet (171) to the downstream outlet (172).

7. A texturing apparatus (114) for gas-dynamic texturing of a yarn (119), the texturing apparatus comprising:

• an fluid inlet (130) for a fluid under pressure for gas-dynamic texturing of the yarn in the texturing apparatus;

• a yarn channel (126) having a yarn inlet (125), the fluid inlet (130) being fluidly coupled to the yarn inlet (125); and

• the gas-dynamic yarn texturing expansion chamber (147, 147a-d) as claimed in any one of the preceding claims leading out of the yarn channel (126) downstream thereof.

8. The texturing apparatus of claim 7, the texturing apparatus further comprising:

• a housing (123), wherein the yarn channel (126) is arranged within the housing (123), and

• a release mechanism for detaching the inlet of the expansion chamber (147, 147a-d) from the housing (123).

9. The texturing apparatus of claim 7 or 8, comprising

• a heating device (129; 132; 134) being configured to heat the texturing apparatus through physical contact with the texturing apparatus or by electromagnetic induction; and/or

• a fluid flow sensor (174) being configured to register an egress of the fluid through at least a portion of the sidewall of the gas-dynamic yarn texturing expansion chamber; and/or;

• means (176, 178) for entraining of the yarn so that it runs concurrently with the fluid in the yarn channel.

10. A system for manufacturing of an artificial turf, the system comprising:

• a texturing apparatus as claimed in any one claims 7 through 9; and

• a system for attaching of the textured artificial turf yarn to a backing of the artificial turf.

11. A method of manufacturing a textured yarn, the method comprising

- texturing (190; 600) a yarn in the texturing apparatus as claimed in any one of claims 7 through 9 to provide the textured yarn, wherein the texturing comprises:

• injecting a fluid under pressure into the texturing apparatus via the fluid inlet (130),

• injecting a yarn into the texturing apparatus via a yarn inlet port (124) of the texturing apparatus, and

• subjecting, inside the gas-dynamic yarn texturing expansion chamber (147; 147a-d), the flowing yarn to a turbulent flow of the fluid so that the texturing of the flowing yarn occurs.

12. The method of claim 11, wherein the method comprising:

- heating (190) the texturing apparatus by a heating device (132; 129; 132, 129) in order to maintain a temperature of the texturing apparatus at a desired temperature,

- manufacturing (190) the yarn, and

- repeating a procedure at predefined or varying time intervals, in particular when at least one of the following criteria is complied with:

a) a flow of the fluid egressing through at least a portion of the sidewall is below a predefined value,

b) the texturing of the yarn is performed for a predefined time interval, and

c) a predefined length of the yarn is textured by performing the texturing of the yarn;

wherein the procedure comprises:
interrupting (196) the texturing of the yarn by terminating the injecting of the yarn being manufactured into the texturing apparatus and guiding the yarn being manufactured away from the texturing apparatus;

- substituting (198) the gas-dynamic yarn texturing expansion chamber by another gas-dynamic yarn texturing expansion chamber in the texturing apparatus after the interrupting of the texturing of the yarn;

- resuming (200) the injecting of the yarn being manufactured into the texturing apparatus after the substituting of the gas-dynamic yarn texturing expansion chamber by the other gas-dynamic yarn texturing expansion chamber in the texturing apparatus; and

- resuming (202) the texturing of the yarn after the resuming of the injecting of the yarn being manufactured and when the temperature of the texturing apparatus is at the desired temperature.

13. A textured yarn (122) manufactured according to the method as claimed in claim 11 or 12.

14. A method of manufacturing an artificial turf (146), wherein the method comprises:

- manufacturing a textured artificial turf yarn according to the method as claimed in claim 11 or 12;

- tufting the textured artificial turf yarn (122) into a backing (142) of the artificial turf.

15. An artificial turf (146) manufactured according to the method of claim 14.

Drawing