Method for manufacturing a warp-knit, non-run elastic fabric, and fabric obtained with said method

Abstract

 The method envisions the loading on a warp-knit machine of at least one elastic yarn and at least one non-elastic yarn, the elastic yarn being fed by the front needle guide bar and the non-elastic yarn being fed by the rear needle guide bar, both in the same direction. The non-elastic yarn is a FOY-type polyamide yarn, and precisely Nylon 6 with fibre gauge of 44 dtex and 26 filaments and an ultimate elongation in the range of 30 - 35%, a modulus of elasticity in the range of 21 - 25 cN/dtex, and a boiling water shrinkage in the range of 13 - 14%. The fabric obtained has high elasticity, fineness, a soft and natural hand, high modulus of elasticity, and is resistant to deterioration by chlorine and indicated primarily for knit underwear, swimsuits, and sportswear.

Description

FIELD OF THE INVENTION

[0001] The subject of the present invention is a method for manufacturing a warp-knit, non-run, elastic fabric of the type specified in the preamble of Claim 1. The invention also relates to the fabric obtained with said method.

[0002] More in particular, the invention relates to a method wherein at least one non-elastic yarn and at least one elastic or elastomeric yarn are loaded on a warp-knit machine equipped with at least one needle bar and at least one front needle guide bar, and one rear needle guide bar through which the yarns are fed to the needles in order to form a warp-knit, non-run, elastic fabric with a particularly high degree of elasticity and fineness capable of creating a soft and silky leather effect.

DESCRIPTION OF PRIOR ART

[0003] A method of this kind is already known from the Patent EP-B1-0 452 607 of the same Applicant.

[0004] According to this method, the elastic yarn is fed to the needles through the front bar and is knit with a tricot structure while the non-elastic yarn is fed to the needles by the rear bar and is knit using a zigzag structure by skipping one or more needles.

[0005] The front and rear bars are driven back and forth simultaneously in the same direction, therefore the elastic and the non-elastic yarns run in zigzag in the same direction, both forming healds on all the machine's needles.

[0006] According to one aspect of the known method, when the fabric is unloaded from the machine, the elastic yarn contracts and brings the sections of non-elastic yarn into a position protruding from the plane of the fabric, and this position is particularly suited to obtain a elastic fabric with leather effect and an extraordinarily uniform structure through subsequent teaseling and cropping or emerizing.

[0007] The fabric thus obtained can also be subjected to thermosetting and/or a dyeing process.

[0008] The fact that both the elastic and non-elastic yarns run in the same direction in the sections between one heald stitch and the next, allows a particularly uniform effect as well as a great efficiency during the dyeing of the finished fabric, because the similar orientation of the yarns hides any irregularity in the dyeing of the elastic yarn, which - as it is known - is notoriously difficult to dye.

[0009] As regards the yarns used in this known method, elastic yarns with a fibre gauge preferably in the range of 22 - 56 dtex are particularly preferred, especially 44 dtex, together with nylon yarns in general, and in particular, Nylon 6, with fibre gauge preferably in the range of 22 - 100 dtex, - 44 dtex in particular - with 36 filaments.

[0010] The method according to this previous European patent has been further perfected by the Applicant, by knitting with tricot structure also the non-elastic yarn, by always making both the elastic and the non-elastic yarns run in the same direction, and by feeding the elastic yarn always from the front bar.

[0011] In addition to its characteristic fineness and soft hand, the fabric obtained in this way offers the same elasticity in both the directions of length and width and permits the manufacturing of knit garments with greater comfort and tighter fit, allowing the maximum breathability while ensuring the greatest freedom of movement. Furthermore, this fabric provides brighter colours, enhances printing effect, and has a chlorine resistance that is 25% higher than that of traditional warp-knit non-run elastic fabrics.

[0012] Thanks to these features, the fabric can be advantageously applied to the production of knit underwear, swimsuits, and sportswear.

[0013] For the manufacturing of this fabric, the Applicant uses a known nylon yarn with low orientation referred to as LOY (Low Orientation Yarn) which is obtained by low speed spinning that gives it greater compactness and a more crystalline appearance.

[0014] Unlike other polyamide synthetic yarns, such as those referred to as FOY (Fully Oriented Yarn) or POY (Partially Oriented Yarn), LOY yarn is not subjected to stretching together with the spinning of the yarn but is subsequently stretched separately. In particular, LOY yarn doubles in length during stretching, and is therefore wound on spools with tapering ends (cops) and used in this way in warp-knit machines.

[0015] LOY yarn has various advantages over FOY yarn, such as better elastic shape memory, lower ultimate elongation, higher boiling water shrinkage, higher compactness, and greater modulus of elasticity that gives the fabric better containing capacity.

[0016] On the other hand, LOY yarn is more expensive than the FOY yarn , due to its slower spinning speed that provides lower yarn production per hour on one hand, and its necessarily separate stretching phase that requires more costs than when stretching is performed at the same time as spinning, immediately downstream from the same as instead occurs for FOY and POY yarns, on the other.

[0017] Furthermore, also the winding on cops increases costs because it requires lower winding speeds, and the maximum quantity of yarn that can be wound is lower than the speed possible with cylindrical spools.

[0018] On the other hand, the use of more economical non-elastic yarns such as FOY yarns, for example, has not yet provided warp-knit non-run elastic fabrics with the above-mentioned excellent quality characteristics, precisely on account of the reasons above, and also because FOY yarns create a fabric that is more slippery to the touch.

SUMMARY OF THE INVENTION

[0019] In this situation, the technical aim of the present invention is to devise a method for manufacturing a warp-knit non-run elastic fabric capable of substantially overcoming the aforesaid drawbacks.

[0020] Within said technical aim, one important aim of the invention is to provide a method of the above-mentioned type, that permits significant economic savings in the realization of such warp-knit fabric while substantially maintaining the same characteristics of elasticity, modulus, fineness, soft hand, breathability, chlorine resistance capacity, and the capacity to enhance the colours in warp-knit, non-run, elastic fabrics produced by the Applicant so far using more costly synthetic LOY yarns .

[0021] Another important aim of the invention is the realization of a fabric of the type specified above, for manufacturing garments that guarantee the highest levels of comfort with perfect adherence and without compression.

[0022] Yet another important aim of the invention is the realization of a method of the type specified above, that permits the fabric to be dyed with excellent results in terms of colour uniformity and brightness.

[0023] Yet another aim of the invention is the realization of a method that has lower environmental impact during the fabric dyeing, requiring lower quantity of dye for the same final result.

[0024] Not least of the invention's aims is the use of a known warp-knit machine for the implementation of the method according to the invention, and in particular, the same machines used thus far.

[0025] The technical aim and the objects specified are achieved by a method for manufacturing a warp-knit, non-run elastic fabric according to the appended Claim 1 and a fabric as claimed in Claim 13.

[0026] Preferred embodiments are highlighted in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other characteristics and advantages of the invention are better illustrated in the following detailed description of its preferred embodiments, with reference to the drawings and tables provided in the description.

Fig. 1 shows the ultimate elongation as a function of load, of a LOY yarn with fibre gauge of 44 dtex with 28 filaments used thus far by the Applicant; and

Fig. 2 shows the ultimate elongation as a function of load of a LOY yarn with equal fibre gauge and number of filaments.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] With particular reference to the drawings above, it may be seen that the LOY yarn (Fig. 1) presents an ultimate elongation curve as a function of the load expressed in kN (kiloNewton) that has a relatively steep initial ascending line, which means that with the increase of the load applied to the yarn, the yarn stretches relatively little.

[0029] The curve then flattens out, and even only slight increases in load create relatively large percentages of elongation before the yarn suddenly breaks.

[0030] At equal fibre gauge and number of filaments, standard, traditional FOY yarn, on the other hand (Fig. 2), shows a curve wherein elongation is initially nearly directly proportional to the increase in load expressed in kN and in any case, a lower amount of load is sufficient to obtain the same percentage of elongation as LOY yarn.

[0031] Subsequently, the FOY yarn curve also flattens out, but with the increase in load a significantly greater elongation occurs before final breakage than in LOY yarn.

[0032] It can be inferred that at equal loads (and fibre gauge and number of yarn filaments), the field of use of LOY yarn is characterized by significantly lower elongation percentages than those that occur with FOY yarns.

[0033] A method according to the invention for manufacturing a warp-knit non-run elastic fabric envisions, in a way known from the European patent EP-B1-0 462 607 filed by the same Applicant, that at least one non-elastic yarn be knit with at least one elastic yarn on a warp-knit machine of a type already known (such as, for example, a machine produced by the Karl Mayer Company of Obertshausen, Germany, as described in further detail below), equipped with at least one needle bar and at least one front needle guide bar and one rear needle guide bar.

[0034] Always in a way known per se, from the above-mentioned European patent, the elastic yarn is fed to the needles through the front needle guide bar, while the non-elastic yarn is fed to the needles through the rear needle guide bar. Since they are loaded in the same direction, both the elastic yarn and the non-elastic yarn extend in the same direction in the passage from one needle to the next.

[0035] The non-elastic yarn is a polyamide yarn, and in particular, a nylon yarn like Nylon 6 or Nylon 66 with numerous filaments. According to the invention, this yarn is a FOY yarn.

[0036] The elastic yarn can be a yarn of the type commercially known as Lycra®.

[0037] As mentioned above, in its standard traditional type, FOY yarn does not permit the creation of a fabric with characteristics of shape memory, modulus of elasticity, soft hand, fineness etc. that can be compared to those provided by the fabric realized by the Applicant using LOY yarn.

[0038] The Applicant has now surprisingly discovered that a fabric of quality and characteristics that are practically the same as those displayed by FOY yarn can be obtained by appropriately modifying, in careful combination, a few of the traditional (standard) FOY yarn parameters.

[0039] More particularly, the Applicant has surprisingly observed that at equivalent yarn fibre gauge - in particular 33 dtex or 44 dtex - and number of filaments, while at least reducing the ultimate elongation and increasing the boiling water shrinkage (BWS) of traditional (standard) FOY yarn, and preferably increasing also the modulus of elasticity while leaving the other textile parameters of this traditional FOY yarn unaltered or substantially at the same level of magnitude, and by knitting the FOY yarn thus modified with the elastic yarn as described above, it is possible to obtain a warp-knit fabric with practically identical characteristics to those previously described obtained by the Applicant with LOY yarn, such as high shape memory, high modulus of elasticity, fineness, soft hand, and high breathability capable of giving garments made with such fabric, the maximum comfort, perfect adherence without compression, and the greatest freedom of movement. More in particular, the Applicant has observed that it is possible to achieve such results by using a FOY yarn with an ultimate elongation in the range of 30 - 35% and Boiling Water Shrinkage (BWS) in the range of 13 -14%, calculated according to the usual method of determining shrinkage as the difference in the yarn's initial length and the length measured after keeping the yarn in a bath of boiling water for a given period of time.

[0040] Advantageously, it is preferable to use a FOY yarn, wherein also the modulus of elasticity is modified, precisely in the range of 21 - 25 cN/dtex.

[0041] Table 1 below provides the most significant textile parameters of standard FOY yarn compared with the same parameters of a FOY yarn according to the invention; such parameters regard a non-elastic Nylon 6 yarn.

[0042] In particular, a Nylon 6 yarn with titanium dioxide (TiO₂) content in the range of 1.1 and 1.7%, and a yarn relative viscosity in the range of 2 and 3 was considered

TABLE 1
	FOY (standard)	FOY (according to the invention)
Fibre gauge	44 dtex/28	44 dtex/28
Ultimate elongation	38%	30 - 35%
Fibre density	5 cN/dtex	3 - 5 cN/dtex
Modulus of elasticity	20 cN/dtex	21 - 25 cN/dtex
Boiling Water Shrinkage (BWS)	11.60%	13 - 14%
Uster (yarn uniformity)	1.10%	1.05 - 1.10%

[0043] As may be seen, in the FOY yarn according to the invention the ultimate elongation is significantly lower than that of standard FOY yarn, boiling water shrinkage is significantly higher, and modulus of elasticity is also higher. The other parameters are substantially unaltered or of the same magnitude. Table 2 below provides the most significant textile parameters of the FOY yarn, which as shown by the tests conducted by the Applicant demonstrated better technical and textile characteristics that were practically equal to the optimal values described above and obtained by the Applicant with LOY yarn.

[0044] In Table 2 below, these optimal textile parameters are compared with those of the LOY yarn used thus far by the Applicant, and reference is always made to Nylon 6 yarn. The table also indicates the TiO₂ content and relative viscosity.

TABLE 2
	FOY (Applicant) (optimal values)	LOY (Applicant) (optimal values)
Fibre gauge	44 dtex/26	44 dtex/28
Ultimate elongation	34.66%	29.59%
Fibre density	5.01 cN/dtex	3.35 cN/dtex
Modulus of elasticity	21.74 cN/dtex	23
Boiling Water Shrinkage (BWS)	13.70%	14%
Uster (yarn uniformity)	1.05%	impossible to determine
TiO2	1.32%	1.615%
Relative viscosity	2.44	2.53

[0045] As may be seen, the optimal values, and especially in regard to ultimate elongation, boiling water shrinkage and modulus of elasticity differ substantially from the corresponding values of LOY yarn (Table 2) and those of standard FOY yarn (Table 1). If, on one hand, the number of nylon filaments was reduced from 28 to 26, on the other, the Applicant was not merely interested in modifying FOY yarn in order to provide it with the textile parameters of LOY yarn. In other words, the Applicant found that only a particular and precisely focused variation of certain parameters was sufficient to achieve the desired results.

[0046] The nylon FOY yarn shown in Table 2 was worked on an HKS 2-3 type 130 inch warp-knit machine manufactured by Karl Mayer.

[0047] This machine with two needle guide bars, one needle bar, and a fineness of 32 was loaded with 4020 yarns per bar with an elastic yarn having a fibre gauge of 44 dtex on the front bar and with circular super-matte non-elastic Nylon 6 FOY yarn with a fibre gauge of 44 dtex and 26 filaments on the rear bar.

[0048] The machine was prepared to work both yarns with tricot structure, both the elastic and non-elastic yarns running in the same direction, more in particular according to the following conditions:

- front bar:
notation	0-1/2-1
length fed	mm/Rk 500
healds per centimetre	28

- rear bar:
Notation	0-1/2-1
length fed	mm/Rk 930

[0049] In particular, the lengths fed are expressed in Rack millimetres. The length fed of the elastic yarn on the front needle guide bar is specified as being in relaxed state.

[0050] The healds per centimetre are defined in the sinker through usual machine adjustments.

[0051] As known, in this preferred embodiments, both the elastic and non-elastic yarns are woven in tricot structure, and both are knit to form open healds.

[0052] The fabric obtained according to the invention can be subjected to a hot dyeing and/or a thermosetting phase.

[0053] The invention achieves important advantages.

[0054] Using this method according to the invention, in fact, it is possible to manufacture a warp-knit, non-run, elastic fabric having the same textile and technical characteristics as the fabric previously obtained with non-elastic LOY yarn, but at significantly lower costs, thanks to the use of the cheaper FOY yarn.

[0055] Said fabric with slender thickness, soft and natural hand, high shape memory, high modulus of elasticity, resistant to deterioration by chlorine, and suited to dyeing for the greater enhancement of colours and printing effects can be used to particular advantage in knit underwear, swimsuits, and sportswear since it ensures greater comfort and tighter fit without compression, while ensuring the maximum breathability and the greatest freedom of movement.

[0056] The reduced TiO₂ content of FOY yarn also offers the advantage of decreased dye consumption during dyeing and consequently less pollution.

[0057] The invention is susceptible to modifications and variants falling within the inventive concept.

[0058] In this way, for example, the elastic yarn and the non-elastic yarn can have a different fibre gauge than the one considered above, such as a fibre gauge of 33 dtex, for example. Moreover, the elastic yarns and the non-elastic yarns do not necessarily have to form tricot structure healds or open healds.

Claims

1. Method per manufacturing of a warp-knit, non-run, elastic fabric wherein at least one non-elastic yarn is loaded with at least one elastic yarn on a warp-knit machine equipped with at least one needle bar and at least one front needle guide bar and one rear needle guide bar, and wherein the elastic yarn is fed through the front bar and the non-elastic bar is fed through the rear bar, with both the elastic yarn and the non-elastic yarn loaded in the same direction,

- characterized by the fact that such non-elastic yarn is a FOY (Fully Oriented Yarn) polyamide yarn with an ultimate elongation in the range of 30 - 35% and a boiling water shrinkage in the range of 13 - 14%.

2. Method according to Claim 1, wherein such non-elastic yarn also presents a modulus between 21 - 25 cN/dtex.

3. Method according to Claim 1 or 2, wherein such non-elastic yarn is a Nylon 6 or Nylon 66 yarn with numerous filaments.

4. Method according to Claim 3, wherein such nylon yarn has a fibre gauge of 33 or 44 dtex and is of the 26-filaments type.

5. Method according to one or more of the previous claims, wherein such elastic yarn has a fibre gauge of 33 or 44 dtex.

6. Method according to Claims 4 and 5, wherein such ultimate elongation is substantially equal to 34.66%.

7. Method according to Claims 4 and 5, wherein such boiling water shrinkage (BWS) is substantially equal to 13.70%.

8. Method according to Claims 4 and 5, wherein such modulus of elasticity is substantially equal to 21.74 cN/dtex.

9. Method according to Claim 1, wherein at least one such non-elastic yarn and at least one such elastic yarn are both knit with a tricot structure.

10. Method according to Claim 1 o 9, wherein at least one such non-elastic yarn and at least one such elastic yarn both form open healds (notations 0-1/2-1 for both yarns).

11. Method according to one or more of the previous claims, wherein such fabric is subjected to a hot dyeing phase.

12. Method according to one or more of the previous claims, wherein such fabric is subjected to a thermosetting phase.

13. Warp-knit, non-run, elastic fabric obtained through the method according to one or more of Claims 1 to 12, realized by at least one non-elastic yarn and at least one elastic yarn characterized in that at least one such non-elastic yarn is a FOY type polyamide yarn with an ultimate elongation in the range of 30 - 35% and a boiling water shrinkage (BWS) in the range of 13 - 14%.

14. Fabric according to Claim 13, wherein at least one such non-elastic yarn has a modulus of elasticity in the range of 21 - 25 cN/dtex.

15. Fabric according to Claim 13, wherein at least one such non-elastic yarn is a Nylon 6 or a Nylon 66 yarn with a fibre gauge of 33 or 44 dtex and 26 filaments and wherein at least one such elastic yarn has a fibre gauge of 33 o 44 dtex, and wherein such non-elastic yarn has an ultimate elongation equal to 34.66%, a modulus of elasticity equal to 21.74 cN/dtex, and a boiling water shrinkage equal to 13.70%.

Drawing