FIELD OF THE INVENTION
[0001] The present invention relates to equipment for forming fibrous fabrics comprising
a mixture of shaped fibers.
BACKGROUND OF THE INVENTION
[0002] Commercial woven and nonwoven fabrics are typically comprised of synthetic polymers
formed into fibers. These fabrics are typically produced with solid fibers that have
a high inherent overall density, typically in the range of from about 0.9g/cm
3 to about 1.4g/cm
3. The overall weight or basis weight of the fabric is often dictated by a desired
opacity and a set of mechanical properties of the fabric to promote an acceptable
thickness, strength, and protection perception.
[0003] One reason for the increased usage of polyolefinic polymers, mainly polypropylene
and polyethylene, is that their bulk density is significantly lower than polyester,
polyamide and regenerated cellulose fiber. Polypropylene density is around about 0.9g/cm
3, while the regenerated cellulose and polyester density values can be higher than
about 1.35g/cm
3. The lower bulk density means that at equivalent basis weight and fiber diameter,
more fibers are available to promote a thickness, strength and protection perception
for the lower density polypropylene.
Another method of addressing consumer acceptance by increasing the opacity of a fabric
is by reducing the overall fiber diameter or denier. In fabrics, the spread of "microfiber"
technology for improved softness and strength has become fashionable.
[0004] Other ways to improve opacity and strength while reducing basis weight and cost at
the same time is desired.
With respect to the prior art attention is drawn to
US 5 417 902 A which discloses polyester mixed fine filament yarns having excellent mechanical quality
and uniformity, and preferably with a balance of good dyeability and shrinkage, which
are prepared by a simplified direct spin-orientation process by selection of polymer
and spinning conditions.
Further,
WO 03/016606 A discloses nonwoven fabrics containing filaments of at least two different cross sections.
The subject invention further pertains to methods used to produce these fabrics. In
an embodiment specifically exemplified herein, the nonwoven fabric of the subject
invention is made of nylon.
WO 00/48478 A discloses a fiber spinning apparatus and process for making a web of fibers including
a homogeneous mixture of fibers of different characteristics. A preferred die assembly
includes a mounting block, a right-hand nozzle, a distribution plate system including
a secondary distribution plate, a right distribution plate, a left distribution plate,
and a secondary left distribution plate, with a left-hand nozzle and a clamp block
on the downstream end.
SUMMARY OF THE INVENTION
[0005] The present invention relates to a spin pack assembly as defined in claim 1. Preferred
embodiments of the invention are disclosed in the dependent claims.
[0006] In accordance with the present invention, a spinneret comprising at least two spinneret
orifices having geometries distinct from each other is provided to form mixed filament
fiber products. The different spinneret orifices can be provided at any selected ratio,
and any types of cross-sectional fiber geometries can be formed (e.g., multi-lobal,
mixed multi-lobal and round of various sizes).
[0007] In accordance with another embodiment of the present invention, a metering/distribution
plate is provided for use in a spin pack assembly that comprises a spinneret including
a first set of spinneret orifices and a second set of spinneret orifices, the spinneret
orifices of the first set having geometries distinct from the spinneret orifices of
the second set. The metering/distribution plate comprises a first set of passages
configured to deliver molten polymer flowing through the spin pack assembly to the
first set of spinneret orifices, and a second set of passages configured to deliver
molten polymer flowing through the spin pack assembly to the second set of spinneret
orifices. The passages of the first set may have dimensions that differ from the dimensions
of the passages of the second set, and the dimensions of the passages for each set
are selected to facilitate the formation of extruded fibers through the first and
second sets of spinneret orifices having selected deniers. The metering/distribution
plate decouples the pressure drop from the spinneret orifices to facilitate greater
control in orifice geometry and fiber denier.
[0008] In still another embodiment of the present invention, a spin pack assembly comprises
a spinneret comprising a first set of spinneret orifices and a second set of spinneret
orifices, the spinneret orifices of the first set having geometries distinct from
the spinneret orifices of the second set. The spin pack assembly further comprises
a metering/distribution plate configured to deliver molten polymer flowing through
the spin pack assembly to the spinneret, the metering/distribution plate comprising
a a first set of passages configured to deliver molten polymer flowing through the
spin pack assembly to the first set of spinneret orifices, and a second set of passages
configured to deliver molten polymer flowing through the spin pack assembly to the
second set of spinneret orifices. The spin pack is further configured to receive different
metering/distribution plates, such that one metering/distribution plate can be exchanged
for another depending upon a particular application.
[0009] The above and still further objects, features and advantages of the present invention
will become apparent upon consideration of the following detailed description of specific
embodiments thereof, particularly when taken in conjunction with the accompanying
drawings wherein like reference numerals in the various figures are utilized to designate
like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010]
Figure 1 illustrates a cross-sectional view of a round hollow fiber with a shaped
hollow core.
Figure 2 illustrates a cross-sectional view of a round hollow fiber which has a round
hollow core.
Figures 3A-3D illustrate cross-sectional views of several shaped fibers.
Figures 4A-4E illustrate cross-sectional views of several shaped hollow fibers.
Figure 5A depicts a bottom view in plan of a portion of a spinneret in accordance
with an embodiment of the present invention, in which the quench air direction is
shown with arrows and the spinneret includes trilobal and solid round spinneret orifices
in a ratio of about 90:10 of trilobal to round.
Figures 5B and 5C depict the orifice configurations for forming solid round and trilobal
fibers with the spinneret of Figure 5A.
Figure 5D depicts an enlarged view of a portion of the spinneret of Figure 5A.
Figure 6A depicts a bottom view in plan of a portion of a spinneret in accordance
with another embodiment of the present invention, in which the quench air direction
is shown with arrows and the spinneret includes trilobal and solid round spinneret
orifices in a ratio of about 75:25 of trilobal to round.
Figure 6B depicts an enlarged view of a portion of the spinneret of Figure 6A.
Figure 7A depicts a bottom view in plan of a portion of a spinneret in accordance
with another embodiment of the present invention, in which the quench air direction
is shown with arrows and the spinneret includes trilobal and solid round spinneret
orifices in a ratio of about 50:50 of trilobal to round.
Figure 7B depicts an enlarged view of a portion of the spinneret of Figure 7A.
Figure 8A depicts a bottom view in plan of a portion of a spinneret in accordance
with a further embodiment of the present invention, in which the quench air direction
is shown with arrows and the spinneret includes trilobal and hollow round spinneret
orifices in a ratio of about 50:50 of trilobal to round.
Figures 8B and 8C depict the orifice configurations for forming hollow round and trilobal
fibers with the spinneret of Figure 8A.
Figure 8D depicts an enlarged view of a portion of the spinneret of Figure 8A.
Figure 9A depicts a bottom view in plan of a portion of a spinneret in accordance
with another embodiment of the present invention, in which the quench air direction
is shown with arrows and the spinneret includes trilobal and solid round spinneret
orifices in a ratio of about 75:25 of trilobal to round, with arrows showing a double
sided quench and a reverse in trilobal spinneret orifice orientation occurring at
opposite locations about a centerline of the spinneret.
Figure 9B depicts an enlarged view of a portion of the spinneret of Figure 9A.
Figure 10A depicts a top view in plan of a portion of a distribution metering plate
that feeds each individual capillary orifice of a spinneret in accordance with the
present invention.
Figure 10B depicts an enlarged view of a portion of the distribution metering plate
of Figure 10A.
Figure 11 depicts an exploded view in elevation and partial section of a spin pack
assembly in accordance with the present invention including two melt pumps for supplying
and regulating molten polymer flow through the assembly.
Figure 12 depicts an exploded view in elevation and partial section of a spin pack
assembly in accordance with the present invention including a single melt pump for
supplying molten polymer to the assembly.
Figure 13 depicts an exploded view in elevation and partial section of another spin
pack assembly in accordance with a reference example including a single melt pump
for supplying molten polymer to the assembly.
Figure 14A depicts a perspective view of a drilled metering plate for use with a spin
pack assembly in accordance with a reference example.
Figure 14B depicts an enlarged view of a portion of the metering plate of Figure 14A.
Figure 15 depicts a schematic of an exemplary spunbond system incorporating a spin
pack assembly in accordance with the present invention.
Figure 16 is a graph of the opacity measurement for different shaped fibers.
Figure 17 is a chart showing the MD-to-CD ratio of different shaped fibers.
Figure 18 is a graph of the CD tensile strength of different shaped fibers.
DETAILED DESCRIPTION OF THE INVENTION
[0011] All percentages, ratios and proportions used herein are by weight percent of the
composition, unless otherwise specified. Examples in the present application are listed
in parts of the total composition.
[0012] The specification contains a detailed description of (1) materials of the present
invention, (2) configuration of the fibers, (3) distribution of fiber mixtures, (4)
material properties of the fibers, (5) equipment and processes, and (6) articles.
(1) Materials
[0013] Thermoplastic polymeric and non-thermoplastic polymeric materials may be used in
the present invention. The thermoplastic polymeric material must have rheological
characteristics suitable for melt spinning. The molecular weight of the polymer must
be sufficient to enable entanglement between polymer molecules and yet low enough
to be melt spinnable. For melt spinning, thermoplastic polymers having molecular weights
below about 1,000,000 g/mol, preferably from about 5,000 g/mol to about 750,000 g/mol,
more preferably from about 10,000 g/mol to about 500,000 g/mol and even more preferably
from about 50,000 g/mol to about 400,000 g/mol.
[0014] The thermoplastic polymeric materials must be able to solidify relatively rapidly,
preferably under extensional flow, and form a thermally stable fiber structure, as
typically encountered in known processes such as a spin draw process for staple fibers
or a spunbond continuous fiber process. Preferred polymeric materials include, but
are not limited to, polypropylene and polypropylene copolymers, polyethylene and polyethylene
copolymers, polyester, polyamide, polyimide, polylactic acid, polyhydroxyalkanoate,
polyvinyl alcohol, ethylene vinyl alcohol, polyacrylates, and copolymers thereof and
mixtures thereof. Other suitable polymeric materials include thermoplastic starch
compositions as described in detail in
U.S. publications 2003/0109605A1 and
2003/0091803. Other suitable polymeric materials include ethylene acrylic acid, polyolefin carboxylic
acid copolymers, and combinations thereof.
[0015] The shaped fibers of the present invention may be comprised of a non-thermoplastic
polymeric material. Examples of non-thermoplastic polymeric materials include, but
are not limited to, viscose rayon, lyocell, cotton, wood pulp, regenerated cellulose,
and mixtures thereof. The non-thermoplastic polymeric material may be produced via
solution or solvent spinning. The regenerated cellulose is produced by extrusion through
capillaries into an acid coagulation bath.
[0016] Depending upon the specific polymer used, the process, and the final use of the fiber,
more than one polymer may be desired. The polymers of the present invention are present
in an amount to improve the mechanical properties of the fiber, improve the processability
of the melt, and improve attenuation of the fiber. The selection and amount of the
polymer will also determine if the fiber is thermally bondable and affect the softness
and texture of the final product. The fibers of the present invention may be comprised
of a single polymer, a blend of polymers, or be multicomponent fibers comprised of
more than one polymer.
[0017] Multiconstituent blends may be desired. For example, blends of polyethylene and polypropylene
(referred to hereafter as polymer alloys) can be mixed and spun using this technique.
Another example would be blends of polyesters with different viscosities or termonomer
content. Multicomponent fibers can also be produced that contain differentiable chemical
species in each component. Non-limiting examples would include a mixture of 25 melt
flow rate (MFR) polypropylene with 50MFR polypropylene and 25MFR homopolymer polypropylene
with 25MFR copolymer of polypropylene with ethylene as a comonomer.
[0018] Optionally, other ingredients may be incorporated into the spinnable composition.
The optional materials may be used to modify the processability and/or to modify physical
properties such as opacity, elasticity, tensile strength, wet strength, and modulus
of the final product. Other benefits include, but are not limited to, stability, including
oxidative stability, brightness, color, flexibility, resiliency, workability, processing
aids, viscosity modifiers, and odor control. Examples of optional materials include,
but are not limited to, titanium dioxide, calcium carbonate, colored pigments, and
combinations thereof. Further additives including, but not limited to, inorganic fillers
such as the oxides of magnesium, aluminum, silicon, and titanium may be added as inexpensive
fillers or processing aides. Other suitable inorganic materials include, but are not
limited to, hydrous magnesium silicate, titanium dioxide, calcium carbonate, clay,
chalk, boron nitride, limestone, diatomaceous earth, mica glass quartz, and ceramics.
Additionally, inorganic salts, including, but not limited to, alkali metal salts,
alkaline earth metal salts and phosphate salts may be used.
(2) Configuration
[0019] The fiber shapes in the present invention may consist of solid round, hollow round
and various multi-lobal shaped fibers, among other shapes. A mixture of shaped fibers
having cross-sectional shapes that are distinct from one another is defined to be
at least two fibers having cross-sectional shapes that are different enough to be
distinguished when examining a cross-sectional view with a scanning electron microscope.
For example, two fibers could be trilobal shape but one trilobal having long legs
and the other trilobal having short legs. Although not preferred, the shaped fibers
could be distinct if one fiber is hollow and another solid even if the overall cross-sectional
shape is the same.
[0020] The multi-lobal shaped fibers may be solid or hollow. The multi-lobal fibers are
defined as having more than one critical point along the outer surface of the fiber.
A critical point is defined as being a change in the absolute value of the slope of
a line drawn perpendicular to the surface of fiber when the fiber is cut perpendicular
to the fiber axis. Shaped fibers also include crescent shaped, oval shaped, square
shaped, diamond shaped, or other suitable shapes.
[0021] Solid round fibers have been known to the synthetic fiber industry for many years.
These fibers have a substantially optically continuous distribution of matter across
the width of the fiber cross section. These fibers may contain microvoids or internal
fibrillation but are recognized as being substantially continuous. There are no critical
points for the exterior surface of solid round fibers.
[0022] The hollow fibers of the present invention, either round or multi-lobal shaped, will
have a hollow region. A solid region of the hollow fiber surrounds the hollow region.
The perimeter of the hollow region is also the inside perimeter of the solid region.
The hollow region may be the same shape as the hollow fiber or the shape of the hollow
region can be non-circular or non-concentric. There may be more than one hollow region
in a fiber.
[0023] The hollow region is defined as the part of the fiber that does not contain, any
material. It may also be described as the void area or empty space. The hollow region
will comprise from about 2% to about 60% of the fiber. Preferably, the hollow region
will comprise from about 5% to about 40% of the fiber. More preferably, the hollow
region comprises from about 5% to about 30% of the fiber and most preferably from
about 10% to about 30% of the fiber. The percentages are given for a cross sectional
region of the hollow fiber (i.e. two dimensional). If described in three dimensional
terms, the percent void volume of the fiber will be equivalent to the percent of hollow
region.
[0024] The percent of hollow region must be controlled for the present invention. The percent
hollow is preferably not below 2% or the benefit of the hollow region is not significant.
However, the hollow region must not be greater than 60% or the fiber may collapse.
The desired percent hollow depends upon the materials used, the end use of the fiber,
and other fiber characteristics and uses.
[0025] The fiber "diameter" of the shaped fiber of the present invention is defined as the
circumscribed diameter of the outer perimeter of the fiber. For a hollow fiber, the
diameter is not of the hollow region but of the outer edge of the solid region. For
a non-round fiber, fibers diameters are measured using a circle circumscribed around
the outermost points of the lobes or edges of the non-round fiber. This circumscribed
circle diameter may be referred to as that fiber's effective diameter. Preferably,
the fiber will have a diameter of less than 200 micrometers. More preferably the fiber
diameter will be from about 3 micrometers to about 100 micrometers and preferably
from about 3 micrometer to about 50 micrometers. Fiber diameter is controlled by factors
including, but not limited to, spinning speed, mass throughput, temperature, spinneret
geometry, and blend composition. The term spundlaid diameter refers to fibers having
a diameter greater than about 12.5 micrometers. This is determined from a denier of
greater than about 1.0dpf. The basis for using denier in this invention is polypropylene.
A 1.0 denier polypropylene fiber that is solid round with a density of about 0.900g/cm3
has a diameter of 12.55 micrometers. Spunlaid diameters are typically from about 12.5
to about 200 microns and preferably from about 12.5 to about 150 microns. Meltblown
diameters are smaller than spunlaid diameters. Typically, meltblown diameters are
from about 0.5 to about 12.5 micrometers. Preferable meltblown diameters range from
about 1 to about 10 micrometers.
[0026] The average fiber diameter of two or more shaped fibers having cross-sectional shapes
that are distinct from on another is calculated by measuring each fiber type's average
diameter, adding the average diameters together, and dividing by the total number
of fiber types (different shaped fibers). The average fiber denier is also calculated
by measuring each fiber type's average denier, adding the average deniers together,
and dividing by the total number of fiber types (different shaped fibers). A fiber
is considered having a different diameter or denier if the average diameter is at
least about 10% higher or lower. The two or more shaped fibers having cross-sectional
shapes that are distinct from one another may have the same diameter or different
diameters. Additionally, the shaped fibers may have the same denier or different denier.
In some embodiments, the shaped fibers will have different diameters and the same
denier.
[0027] The shaped fibers of the present invention will have a lower overall apparent bulk
density. The apparent bulk density is less than the actual density of the same polymeric
composition used for of a solid round fiber with the same circumscribed diameter.
The apparent bulk density will be from about 2% to about 50% and preferably from about
5% to about 35% less than the actual density. Apparent bulk density, as used herein,
is defined as the density of a shaped fiber with a circular circumscribed diameter
as if it were a solid round fiber. The apparent bulk density is less because the mass
of the fiber is reduced while the circumscribed volume remains constant. The mass
is proportional to the area. For example, the apparent bulk density of a tribal fiber
is the circumscribed area of the shaped fiber. Therefore, the apparent bulk density
is calculated by measuring the total solid area compared to the total circumscribed
area. Similarly, the apparent bulk density of a hollow round fiber is measured by
the total circumscribed area of the fiber minus the area of the hollow region. The
apparent bulk density of the collection of shaped fibers in a layer can also be calculated.
[0028] Figure 1 illustrates a round hollow fiber. The shape of the hollow region of this
fiber is not round. Figure 2 is used to illustrate a round hollow fiber. As shown,
the center of the hollow region and the center of the hollow fiber are the same. Additionally,
the shape or curvature of the perimeter of the hollow region and the hollow fiber
are the same. Figures 3A-3D illustrate several different shapes of the fibers including
various trilobal and multi-lobal shapes. Figures 4A-4E illustrate shaped hollow fibers.
[0029] Multi-lobal fibers include, but are not limited to, the most commonly encountered
versions such as trilobal and delta shaped. Other suitable shapes of multi-lobal fibers
include triangular, square, star, or elliptical. These fibers are most accurately
described as having at least one critical point. Multi-lobal fibers in the present
invention will generally have less than about 50 critical points, and most preferably
less than about 20 critical points. The multi-lobal fibers can generally be described
as non-circular, and may be either solid or hollow.
[0030] The mono and multiconstituent fibers of the present invention may be in many different
configurations. Constituent, as used herein, is defined as meaning the chemical species
of matter or the material. Fibers may be of monocomponent in configuration. Component,
as used herein, is defined as a separate part of the fiber that has a spatial relationship
to another part of the fiber.
[0031] The fibers of the present invention may be multicomponent fibers. Multicomponent
fibers, commonly a bicomponent fiber, may be in a side-by-side, sheath-core, segmented
pie, ribbon, or islands-in-the-sea configurations. Alternativel, the multicomponent
fibers may be mixed homo or single component fibers. The sheath may be non-continuous
or continuous around the core. If present, a hollow region in the fiber may be singular
in number or multiple. The hollow region may be produced by the spinneret design or
possibly by dissolving out a water-soluble component, such as PVOH, EVOH and starch,
for non-limiting examples.
(3) Distribution of Fiber Mixtures
[0032] The fiber shapes in the present invention are mixed together in a single layer to
provide a synergistic effect versus the presence of substantially all round fibers
alone or substantially all non-round fibers alone. "Substantially all" is defined
as having less than about 5% of different shapes and is not intended to exclude layers
wherein less than 5% of the fibers are different due to not being able to completely
control the process. The mixture of shaped fibers having cross-sectional shapes that
are distinct from one another in a single layers is also more beneficial that a nonwoven
with discrete layers of fibers having distinct cross-sectional shapes. For example,
the fibrous fabric of the present invention may perform differently and be more desired
than a nonwoven laminate where one distinct layer has substantially all solid round
fibers and another distinct layer has substantially all trilobal fibers. These benefits
may be observed in opacity and/or mechanical properties. It is believed that the mixture
of shaped fibers in a single layer may be beneficial because the different shapes
may prevent roping or other non-uniformity issues during production.
[0033] Due to the need to control fabric opacity and mechanical properties, numerous combinations
of fibers shapes mixed together are possible. In general, the fiber mixtures will
comprise solid round and hollow round, solid round and multi-lobal, hollow round and
multi-lobal, and solid round and hollow round and multi-lobal and combinations thereof.
[0034] In order to manifest the additional benefits of fiber mixtures, the minor component
of the mixture must be present in sufficient amount to enable differentiation versus
100% isotropically shaped fibers. Therefore, the minor component is present in at
least 5% by weight mass of the total fiber composition. Each of the two different
shaped fibers can comprise from about 5% by weight to about 95% by weight. The specific
percent of each fiber desired depends upon the use of the nonwoven web and specific
shape of the fiber.
(4) Material Properties
[0035] The fibrous fabrics of the present invention will have a basis weight and opacity
that can be measured. Opacity can be measured using TAPPI Test Method T 425 om-01
"Opacity of Paper (15/d geometry, Illuminant A/2 degrees, 89% Reflectance Backing
and Paper Backing)". The opacity is measured as a percentage. The opacity of the fibrous
fabric comprising at least one layer comprising a mixture of shaped fibers having
cross-sectional shapes that are distinct from one another will be several percentage
points of opacity greater than the fibrous fabric containing substantially all round
fibers with the same average fiber denier and basis weight and made of the same polymeric
material. The opacity may be from about 2 to about 50 percentage points greater and
commonly from about 4 to about 30 percentage points greater. Preferably, the opacity
will be at least about 5% greater, more preferably 7% greater, and most preferably
about 10% greater.
[0036] Figure 16 is a graph of the percent opacity versus basis weight for several different
fiber shapes and mixtures of shaped fibers. As can be seen, a mixture of 75% trilobal
fibers and 25% solid round fibers and a mixture of 50% trilobal fibers and 50% solid
round fibers both have higher opacity measurements at equivalent basis weights than
100% hollow round fibers and 100% solid round fibers.
[0037] Basis weight is the mass per unit area of the substrate. Independent measurements
of the mass and area of a specimen substrate are taken and calculation of the ratio
of mass per unit area is made. Preferably, the basis weight of the layer comprising
a mixture of shaped fibers having cross-sectional shapes that are distinct from one
another will be from about 1 grams per square meter (gsm) to about 150 gsm depending
upon the use of the fibrous fabric. More preferable basis weights are from about 2
gsm to about 30 gsm and from about 4 gsm to about 20 gsm. The basis weight of the
total fibrous fabric (including the layer comprising a mixture of shaped fibers) is
from about 4 gsm to about 500 gsm, preferably from about 4 gsm to about 250 gsm, and
more preferably from about 5 gsm to about 100 gsm.
[0038] Additionally, the fibrous fabrics produced from the shaped fibers will also exhibit
certain mechanical properties, particularly, strength, flexibility, elasticity, extensibility,
softness, thickness, and absorbency. Measures of strength include dry and/or wet tensile
strength. Flexibility is related to stiffness and can attribute to softness. Softness
is generally described as a physiologically perceived attribute that is related to
both flexibility and texture. Absorbency relates to the products' ability to take
up fluids as well as the capacity to retain them. The fibrous fabrics of the present
invention will also have desirable barrier properties.
[0039] Preferably, the fibrous fabric comprising at least one layer comprising a mixture
of shaped fibers having cross-sectional shapes that are distinct from one another
will have a machine direction to cross-machine direction ratio (MD-to-CD ratio) lower
than a fibrous fabric produced with substantially all trilobal cross-sectional fibers
having the same polymeric material, equivalent fiber denier, and basis weight. Additionally,
it is desired that the fibrous fabric of the present invention will also have a CD
strength and/or total (MD+CD) strength that is greater than the fibrous fabric with
substantially all trilobal cross-sectional fibers. Having the MD-to-CD ratio lower
than a substantially all trilobal layer can be desired as the CD strength of the trilobal
layers is not as high as desired and the MD strength may be too high. It is desired
to have a relatively high CD strength in a layer so that the basis weight does not
need to be increased to achieve the relatively high CD strength. The relatively high
CD strength is desired in some application for keeping the tabs and/or fasteners attached
in an absorbent article. If the MD strength is too high (or the basis weight must
be increased to increase the CD strength creating a very high MD strength), issues
in the converting process may occur. Therefore, to get the best performance, it is
desired to control the MD-to-CD strength ratio and keep a high total strength. The
MD and CD tensile strengths can be measured by ASTM D1682.
[0040] Figure 17 is a chart of the MD-to-CD ratio for several different fiber shapes and
mixtures of shaped fibers. As can be seen, a mixture of 75% trilobal fibers and 25%
solid round fibers and a mixture of 50% trilobal fibers and 50% solid round fibers
both have a lower MD-to-CD ratio than 100% trilobal fibers. Figure 18 is a graph of
CD tensile strength versus bonding temperature for several different fiber shapes
and mixtures of shaped fibers. As can be seen, a mixture of 75% trilobal fibers and
25% solid round fibers and a mixture of 50% trilobal fibers and 50% solid round fibers
both have a higher CD strength at all bonding temperatures than 100% trilobal fibers.
(5) Equipment and Processes
[0041] The fibrous fabric formed by the equipment of the present invention is a spunmelt
nonwoven fibrous fabric. Spunmelt is defined to mean thermoplastic extrusion. Spunmelt
includes spunlaid and meltblown processes. Spunmelt also includes spunbond fabrics.
[0042] The first step in producing a fiber is the heating of raw, extrudable polymer materials
that are typically mixed together as they are melted and/or transported so as to form
a homogeneous melt with proper selection of the composition. The melt is conveyed
(e.g., via one or more extruders and/or melt pumps) through capillaries or channels
to form fibers. The fibers are then attenuated and collected. The fibers are preferably
substantially continuous (i.e., having a length to diameter ratio greater than about
2500:1), and will be referred to as spunlaid fibers. A collection of fibers is combined
together using at least one of heat, pressure, chemical binder, mechanical entanglement,
hydraulic entanglement, and combinations thereof resulting in the formation of a nonwoven
fibrous fabric. The fibrous fabric may then be incorporated into an article.
[0043] Exemplary equipment that can be used to produce any of the shaped fibers and fibrous
fabrics as described herein preferably includes the following main parts: (1) Extruders
and/or melt pumps to melt, mix and meter the polymer component, (2) a spin pack system
or assembly comprising a polymer melt distribution system and spinneret that delivers
a polymer melt(s) to capillaries that have shaped orifices, (3) attenuation device
driven by pneumatic air, positive pressure, direct force and/or vacuum by which air
drag forces act on a polymer stream to attenuate the fiber diameter to smaller than
the orifice overall geometric shape, (4) fiber laydown region where fibers are collected
underneath the attenuation device in a random orientation (defined by having machine
direction and converse direction fiber orientation ratio less than 10), and (5) fiber
bonding system that prevents long range collective fiber movement. Numerous companies
manufacture fiber and fabric making technologies that can be used for the present
invention, non-limiting examples include Hills Inc., Reifenhauser GmbH, Rieter Corporation,
Neumag GmbH, Nordson Fiber Systems and others.
[0044] In particular, the equipment described herein is important for incorporating shaped
fibers in fabrics for better opacity and mechanical properties, where shaped fibers
are typically produced using a special spin pack system that shapes the polymer melt
stream as it exits the spinneret.
[0045] In accordance with the invention, filaments of mixed shapes, such as round and trilobal,
are formed with a spinneret that includes suitable mixtures of orifice geometries
so as to form a blend of two or more types of fibers or filaments having different
shapes or cross-sectional geometries at any selected ratios. While fibers having any
suitable cross-sectional geometries can be formed, preferred blends of fibers are
solid and/or hollow round fibers with multi-lobal fibers. Exemplary multi-lobal fibers
that can be formed with the spinneret include, without limitation, trilobal, delta,
cross shaped, and/or penta-lobal (e.g., shapes such as those described above and depicted
in Figures 3A-3D). Trilobal is a preferred cross section because of the high surface
area to weight ratio of the fiber, and the relative ease of manufacturing the spinneret
orifice. The system can be configured to form mixed filaments that have the same polymer,
the same polymer with different additives, two or more different polymers and/or multi-component
fibers. If multi-component fibers are used, bi-components are the preferred type.
However, other multi-component fiber types can also be formed including, without limitation,
sheath/core, islands-in-the-sea, segmented pie, etc. The locations and orientations
of the different shaped orifices along the spinneret can also enhance the formed product
as described below.
[0046] Figures 5-9 depict exemplary embodiments of spinnerets in accordance with the invention
that yield two types of filament shapes or geometries, namely trilobal and round,
in ratios from 90:10 to 50:50. However, it is noted that the invention is not limited
to such range of ratios. In particular, spinneret configurations are possible that
yield fabrics having different filaments ranging in ratios, for example, from 95:5
to 5:95 for two filament shapes (e.g., 80:20 of multi-lobal to round). In addition,
spinnerets may also include any suitable ratios of more than two different shapes
of fibers. For example, a spinneret can be formed including suitable orifices that
forms any selected ratio (such as a 25:40:35 ratio) of trilobal to solid round to
hollow round filaments.
[0047] The spinneret holes or orifices are also preferably oriented for certain orifice
geometries in a selected manner based upon the direction at which a quenching medium,
such as quench air, is directed to contact the fibers emerging from the spinneret.
For example, when forming trilobal filaments from trilobal shaped spinneret orifices
(e.g., such as fibers depicted in Figures 3A and 3D), optimum spinning conditions
can be achieved when a single tip portion, leg or lobe (e.g., a lobe 1 as indicated
in Figures 3A and 3D) of at least some of the trilobal fibers is aligned or oriented
in a direction toward or facing a source of quenching medium. Other multi-lobal fiber
configurations can also be aligned in a similar manner as the arrangement of trilobal
fibers described above to achieve enhanced spinning conditions. The spinneret orificies
are therefore configured to achieve such an alignment for the multi-lobal fibers emerging
from the spinneret. The orientation of the multi-lobal orifices on a spinneret in
this manner is very important for commercially producing fabrics as described herein,
particularly when utilizing spinnerets having more than one multi-lobal orifice per
1cm
2.
[0048] In the present invention, fiber mixtures are produced by distributing the various
orifice geometries along the bottom or outlet surface of the spinneret to produce
a relatively uniform fiber distribution of shapes on fiber laydown through their spatial
location across the spinneret face. The spinneret includes generally vertical channels
or counterbores that extend from a top or inlet surface of the spinneret to spinneret
orifices disposed at the bottom or outlet surface of the spinneret. Several examples
of spinnerets are shown in Figures 5-9 with different spinneret orifice distributions.
However, it is noted that any suitable spinneret orifice distribution can be configured
for the spinneret in accordance with the invention (i.e., the invention is in no way
limited to these examples).
[0049] Referring to Figure 5A, a spinneret 2 is depicted including a distribution of orifices
that yields a ratio of 90:10 of trilobal to solid round filaments. Figures 5B and
5C respectively depict round orifice 4 and trilobal orifice 6 geometries as can be
seen along the bottom (i.e., outlet) surface of the spinneret. An enlarged view of
a portion of spinneret 2 is depicted in Figure 5D, where it can be seen that the trilobal
orifices 6 are all arranged along the outlet surface of the spinneret in the same
or substantially similar alignment with each other. In particular, the trilobal orifices
6 are formed in the spinneret 2 such that a single lobe of each of the trilobal fibers
emerging from the spinneret is aligned in a direction that generally faces a source
of quench air. In other words, the trilobal fibers are formed such that a single lobe
of each of these fibers is oriented in a direction that opposes a direction in which
quench air (shown by arrows 8 in Figure 5A) is flowing from the quench source to contact
the fibers.
[0050] This trilobal orientation allows the quench air to contact the majority of all the
lobes of the trilobal fibers that are aligned with respect to the quench air, resulting
in highly uniform quenching and physical properties for the fibers. This orientation
also prevents the quench air from potentially rotating the trilobal fibers, which
would have an adverse effect and cause turbulence and filament-to-filament collisions
in the spinning process. As noted above, a spinneret including any number and types
of multi-lobal orifices that produce multi-lobal fibers will benefit from a configuration
similar to that depicted in Figures 5A-5D (as well as Figures 6-9 as described below),
where the fibers are formed such that a lobe of at least some of the fibers emerging
from the spinneret is aligned in a direction that faces the quench source and generally
opposes the flow direction of a quench air used to quench the fibers.
[0051] Figures 6A - 6B and 7A - 7B depict a spinneret including solid round orifices 4 and
trilobal orifices 6, where spinneret 10 of Figure 6A includes a 75:25 ratio of trilobal
to round orifices and spinneret 12 of Figure 7A includes a 50:50 ratio of trilobal
to round orifices. The trilobal orifices in each spinneret 10, 12 are aligned in a
similar manner as the trilobal orifices for spinneret 2 described above and depicted
in Figure 5A, such that a single lobe of each trilobal fiber 6 emerging from the spinneret
is aligned in a direction facing a quench air supply source and generally opposing
the flow direction of quench air (shown by arrows 8) that is used to quench the fibers.
[0052] Figure 8A depicts a spinneret 14 that includes a 50:50 ratio of trilobal orifices
6 and hollow round orifices 7 (i.e., orifices that yield hollow round fibers). The
trilobal orifices are arranged in spinneret 14 such that the trilobal fibers formed
are aligned with respect to the quench air (shown by arrows 8) in the same manner
as described above for the embodiments depicted in Figures 5-7.
[0053] Referring to Figure 9A, a spinneret 20 is depicted that includes a 75:25 ratio of
trilobal orifices 6 to solid round orifices 4. However, in this embodiment, as can
be seen from Figure 9B, fibers emerging from spinneret 20 are subjected to a two-sided
quench, where two streams of quench air are directed in generally opposing directions
with respect to each other toward the fibers and oriented at opposing sides of the
spinneret (depicted as arrows 8 and 9 in Figure 9B). Two-sided quenching is often
desired in spunbond processing to achieve rapid and effective cooling of the extruded
fibers. To achieve a similar benefit as described above for the trilobal fibers being
contacted with the quench air, the orientation or alignment of trilobal orifices 6
disposed along one section of spinneret 20 differs with respect to the orientation
of trilobal orifices 6 disposed along at least one other section of the spinneret.
[0054] In particular, as can be seen in Figure 9B, spinneret 20 includes two halves that
are separated along a centerline (indicated by dashed line 22 in Figure 9B) extending
the length (i.e., between longitudinal ends) of the spinneret. The trilobal orifices
6 on a first half section 24 of the spinneret are aligned or oriented such that a
single lobe of each of the trilobal fibers emerging from spinneret 20 is aligned in
a direction that faces a quench supply providing the closest source of quench air
(indicated by arrows 9) that quenches these fibers. The trilobal orifices 6 on a second
half section 26 of the spinneret, as can be seen from the outlet surface of spinneret
20, have a reverse orientation (i.e., a 180° rotational orientation) in relation to
the trilobal orifices 6 on the first half section 24, such that a lobe of each of
the trilobal fibers emerging from spinneret 20 is aligned in a direction that faces
a quench supply providing the closest source of quench air (indicated by arrows 8)
that quenches these fibers.
[0055] Depending upon the directions of quenching medium flowing toward fibers emerging
from the spinneret, spinnerets can be designed in accordance with the invention including
the same type of multi-lobal orifices formed within the spinneret but with groups
or sections of multi-lobal orifices being arranged along the spinneret in any number
of different orientations with respect to multi-lobal orifices of other sections arranged
along the spinneret, which facilitates the formation of multi-lobal fibers oriented
in a similar manner as described above with respect to the varying directions of quenching
medium flow aimed toward the fibers. For example, a spinneret can include two or more
sections of the same multi-lobal orifices, where the multi-lobal orifices of one section
are oriented on the outlet surface of the spinneret at any suitable angle of rotation
(e.g., 45°, 90°, 135°, 180°, etc.) with respect to multi-lobal orifices of one or
more other sections of the spinneret so as to facilitate alignment of a single lobe
of at least some multi-lobal fibers of a section in a direction generally facing a
closest source of quenching medium that is aimed toward this section of fibers.
[0056] Any suitable selection of grouping of orifices with different shapes or geometries
can be provided on the spinneret to achieve a desired grouping of resultant mixed
filaments or fibers that are extruded from the spinneret. While the embodiments described
above and depicted in Figures 5-9 show orifices arranged in generally straight or
linear rows and columns, the orientation of spinneret orifices is not limited to such
arrangements. Any suitable alignment of spinneret orifices (e.g., selectively patterned
or randomized) may be chosen to reduce turbulence and optimize fiber spinning and
maximize quench rate. For example, in some applications it may be desirable to have
random orientation to aid in the reduction of roping or other non-uniformity issues.
[0057] In another embodiment of the invention, the spinneret with mixed orifice geometries
(e.g., any of the spinnerets described above and depicted in Figures 5-9) can be a
full fabric width spinneret (i.e., a spinneret having a longitudinal dimension of
at least about 500 millimeters).
[0058] In the spinneret embodiment of Figures 9A and 9B, the spinneret orifices are arranged
such that substantially entirely round orifices 4 are disposed at a selected distance
from each of the lengthwise or longitudinal ends of spinneret 20 (as shown by bracket
28 of Figure 9B). This selected distance from the longitudinal ends of the spinneret
corresponds with the edge of the fiber product that is formed and which is typically
trimmed or removed in some manner from the product. It is generally easier to yield
good spinning and prevent or minimize filament breaks with round spinneret orifices,
and round orifices are also less costly to manufacture than multi-lobal orifices.
Thus, as can be seen in Figure 9B, substantially no trilobal orifices are provided
within this selected outer area of the spinneret outlet surface (the area indicated
by bracket 28).
[0059] Preferably, round orifices 4 are also disposed along all of the outer edges of the
spinneret and also at or near the middle portion of the spinneret (as depicted in
Figure 9B), since this is typically where turbulence in fiber flow is the greatest,
and round fibers are less susceptible to twisting or breaking when exposed to turbulence
in comparison to multi-lobal fibers. Thus, a spinneret configuration such as is depicted
in Figures 9A and 9B provides enhanced fabric or other fiber product formation by
minimizing twisting or breakage of fibers (particularly of the multi-lobal fibers)
as well as enhancing the quenching of the formed fibers.
[0060] In addition to enhancing fiber product formation with mixed filament geometries by
designing the spinneret in the manner described above, other components of the spin
pack assembly can be designed to improve system performance and enhance the fiber
product. A flexible spin pack system or assembly is provided in accordance with the
invention, where the spin pack system is utilized in an economical and efficient manner
to produce various types of mixed filaments. The spin pack system can include any
suitable spinneret, such as the spinnerets described above. It is preferable that
the flexible spin pack system, or at least portions of the system (e.g., metering/distribution
plates) are configured to be retrofitted to existing spunlaid lines. The term "spunlaid"
is used herein to describe a spinning system that includes the extruder, polymer metering
system, spinpack, cooling section, fiber attenuation, fiber laydown and deposition
onto a belt or drum and vacuum. The spunlaid system does not denote the type of fiber
consolidation.
[0061] A spunbond line includes a spunlaid line and thermal point bonding. The equipment
before the fiber consolidation is substantially similar or identical on a spunbond
line and a spunlaid line. An exemplary embodiment of a spunbond line is described
below and depicted in Figure 15.
[0062] The flexible spin pack system of the present invention includes a metering/distribution
system that effectively meters and distributes molten polymer to the various spinneret
orifices. Preferably, the spin pack system utilizes one or more low cost metering/distribution
plates. The metering/distribution plates can be of any suitable types, such as those
described in
U.S. Patent No. 5,162,074 ("the '074 patent") so as to deliver and meter the polymer in a homo or multipolymer
system to each spinneret orifice. In particular, a metering/distribution plate includes
horizontal passages (referred to as channels) and vertical flow passages (referred
to as through-holes) that extend within the plate so as to facilitate metering and/or
distribution of polymer flow through the plate and between a top or inlet surface
of the plate and a bottom or outlet surface of the plate, which in turn facilitates
the flow of polymer to the spinneret.
[0063] An exemplary embodiment of an etched metering/distribution plate 30 is depicted in
Figures 10A and 10B. The plate includes a number of passages or channels etched within
and extending generally horizontally along an upper or inlet surface of plate 30.
Alternatively, it is noted that the channels may be formed via a suitable machining
process. The generally horizontally-extending channels are formed having selected
dimensions (e.g., lengths, widths and depths) that facilitate at least partial control
of polymer flow through the metering/distribution plate to the spinneret. The generally
horizontally-extending channels further extend to and are in fluid communication with
vertical passages or through-holes that extend generally vertically within plate 30
to a bottom or outlet surface of the plate. The through-holes are aligned on the metering/distribution
plate such that, when the plate is placed in the spin pack assembly over and in contact
with the spinneret, the through-holes are in fluid communication with capillaries
or counterbores of the spinneret that lead to the spinneret orifices.
[0064] Alternatively, it is noted that the vertical orientation of the etched or machined
metering/distribution plate with respect to the spinneret can also be reversed, such
that the top or inlet surface of the metering/distribution plate includes the through-holes
and the bottom or outlet surface of the plate includes the generally horizontal channels
that are in communication with the counterbores of the spinneret.
[0065] The channel dimensions of each channel of the metering/distribution plate can remain
generally constant or, alternatively, one or more channel dimensions can vary along
the length of the channel between the upstream channel end (i.e., the channel end
that serves as the channel inlet that receives molten polymer from an upstream component
of the spin pack assembly) and the downstream channel end (i.e., the channel end that
is adjacent and communicates with the vertical through-hole of the plate).
[0066] In addition, the transverse cross-sectional geometries of each of the metering/distribution
plate channels can have any suitable shapes, with one or more channel walls being
generally planar, curved (e.g., rounded, concave or convex) and/or pitched at any
selected slopes between the upstream and downstream channel ends. In an exemplary
embodiment, the etched (or machined) channels in the metering/distribution plate can
include a transverse cross-sectional shape including a generally concave bottom surface
and generally flat or planar side wall surfaces. Other cross-sectional channel shapes
can also be provided for the metering/distribution plate. In addition, the metering/distribution
plate channels can be formed with a variety of different length to width and width
to depth ratios, where the selection of specific dimensional ratios will depend upon
a particular application. Exemplary channel width to channel depth ratios for the
metering/distribution plate channels are in the range of about 1.5:1 to about 15:1,
but these ratios can also be larger or smaller depending upon a particular application.
[0067] The vertically extending through-holes of the metering/distribution plate can also
have any suitable dimensions to facilitate a desired flow of polymer through the plate.
However, it is noted that there is greater flexibility in selection of dimensions
for the etched (or machined) and generally horizontally extending channels of the
metering/distribution plate, and polymer flow control through the plate can be controlled
to a large degree by adjustment of these channel dimensions for a particular application.
Thus, a suitable etching process provides an economical and effective metering/distribution
plate that includes elaborate channels with varying dimensions.
[0068] The metering/distribution plate serves a distribution function by delivering molten
polymer, via the various channels in the plate, to selected throughbores and orifices
of the spinneret. The plate further serves a metering function in that each passage
(e.g., etched or machined channel and/or through-hole) that corresponds with a respective
spinneret orifice can be selectively dimensioned (e.g., by selecting etched or machined
channel dimensions such as lengths, widths, depths, diameters, etc.) so as to control
the pressure drop of the polymer flowing through the passage and thus the delivery
of polymer at a desired flow rate to the respective spinneret orifice. This in turn
facilitates the control of the formation of a fiber through the respective spinneret
orifice at a selected denier and cross-sectional dimension (e.g., diameter). The term
"denier," as used herein, refers to the linear mass density of a fiber and is defined
as the mass in grams per 9,000 meters of the fiber.
[0069] As noted above, metering/distribution plates can be made by a low cost etching process,
such as the process described in the '074 patent, to include horizontally aligned
channels and vertically aligned through-holes that form the passages in the plates.
Such channels and through-holes can also be formed in the plate by a machining process.
The passages of the plates can be machined drilled and vertically aligned through-holes,
with the drilled through-holes having suitable dimensions to control pressure drop
in a similar manner as the horizontal channels of an etched or machined plate. The
use of drilled metering plates is described in further detail below.
[0070] The use of a metering/distribution plate in a spin pack system in accordance with
the present invention provides a number of advantages. In particular, the metering/distribution
plate decouples the metering of molten polymer from the spinneret orifice geometry,
which allows fibers to be produced from each spinning orifice at one or more desired
deniers and also allows for optimization of the spinneret orifice geometry for various
other functions, such as polymer shear rate, jet stretch (as described below), as
well as final fiber cross section geometry (e.g., forming sharper or more well-defined
multi-lobal fibers). One skilled in the art will recognize that the final geometry
of an extruded fiber is determined, at least in part, by the design (e.g., geometry
and dimensions) of the spinneret orifice. For example, if a sharp trilobal fiber is
desired with long, extended or skinny legs or lobes, the spinneret orifice will also
require such a shape. However, such a shape may not be consistent with the metering
requirements to produce the desired denier unless at least a portion of the metering
can be controlled with a metering plate or some other suitable pressure control mechanism
disposed upstream of the spinneret orifice.
[0071] Another advantage of the metering/distribution plate in accordance with the invention
is that the plate can be changed (i.e., substituted with another plate) in the spin
pack to facilitate a change of polymer flow to selected spinneret orifices. This results
in a relatively easy and cost effective mechanism for changing the deniers of mixed
fibers formed with different shapes in a single system without necessarily requiring
a modification to the spinneret.
[0072] A still further advantage of the metering/distribution plate in accordance with the
invention is that the plate provides for a low cost retrofit into existing and commercially
plentiful machines, such as machines manufactured by Reifenhauser GmbH (Germany) and
described in
U.S. Patent No. 5,814,349 ("the '349 Patent"). The '349 patent describes a "closed" system, where quench air
is used to both quench and draw the fibers. The metering/distribution plate of the
invention is equally advantageous in "open" systems, where a separate source of compressed
air is used to draw the fibers, such as the system described in
U.S. Patent No, 6,183,684.
[0073] A change in metering of molten polymer to the spinneret orifices may be necessary
based upon any number of desired changes in the physical dimensions or properties
of the fibers formed and/or the process conditions during system operation. For example,
any of the following changes in a system may require a change in metering of polymer
flow through the spinneret orifices: a change in total polymer throughput (e.g., an
increase in polymer throughput or mass flow rate may requires a reduction in pressure
drop to maintain desired fiber denier), a change in denier for one or more sets of
fibers having different cross-sectional geometries, a change in temperature of polymer
flowing through the spin pack assembly (which changes viscosity), and a change in
the ratio of different shaped spinneret orifices (which results in a different number
of formed fibers
having different cross-sectional geometries with respect to the total number of fibers
formed from the spinneret) and/or arrangement or pattern of spinneret orifices disposed
on the spinneret outlet surface (e.g., different arrangements of round orifices to
multi-lobal orifices across the spinneret outlet surface).
[0074] In designing a spin pack assembly, one or more metering/distribution plates may be
provided in the spin pack assembly. For example, a single metering/distribution plate
may be provided. Alternatively, two more more metering/distribution plates can be
provided in a vertically stacked alignment with each other within the spin pack assembly,
where the flow passages of two adjacent plates are in fluid communication with each
other to facilitate the flow of molten polymer material between the two plates.
[0075] As noted above, the metering/distribution plate can be designed for a particular
spin pack system and mixed filament spinneret so as to decouple the pressure drop
from the shear rate and jet stretch, all of which are parameters that otherwise are
typically addressed when selecting geometric designs for the spinneret orifices. In
order to maintain good fiber spinning for a particular application, it is necessary
to control pressure drop, shear rate and jet stretch within predefined values. The
pressure drop of polymer through a spinneret orifice will depend upon the orifice
geometry. For example, in a round spinneret orifice, the pressure drop through the
orifice can be calculated as follows (see, e.g.,
Dynisco, "Extrusion Processors Handbook", 2nd Edition):
where P = pressure drop (psi)
L = Length of capillary (inches)
Tw = Shear stress at wall (psi)
R = radius of capillary (inches)
The shear rate is defined as:
Where y = shear rate (sec-1)
Q = flow rate (in3/sec)
R = radius of capillary (inches)
[0076] The jet stretch is defined as the ratio of the maximum spinning velocity of the fibers
to the velocity of the polymer at the exit of the spinneret hole.
[0077] Since at least two types of different shaped fibers are spun in mixed filament spinning,
it is necessary to independently control the pressure drop, shear rate and jet stretch
through each orifice type (i.e., different shape and/or diameter). By providing greater
control in the pressure drop upstream from the spinneret orifice (e.g., via a suitable
metering/distribution plate), more flexibility is provided in designing spinneret
orifice geometries that are desirable for a particular application. This is achieved
in a number of different embodiments in accordance with the invention.
[0078] One embodiment employs a spin pack assembly and two metering pumps as depicted in
Figure 11. In particular, a spin pack assembly 40 includes, in a vertically stacked
alignment, a pack top 42, a filter support plate 44 disposed beneath the pack top,
filters disposed within a cavity 43 formed between corresponding grooved portions
of the pack top and filter support plate to filter the polymer flowing through the
assembly, a metering/distribution plate 46 disposed beneath the filter support plate
and including suitable channels for directing polymer through plate 46 and to the
spinneret, and a spinneret 48 disposed beneath plate 46 to received metered polymer
to the various orifices of the spinneret.
[0079] The filter support plate 44 includes any suitable series of channels or cavities
disposed at the bottom or outlet surface of the filter support plate to facilitate
fluid communication between polymer flow passages of the filter support plate and
the passages of the metering/distribution plate. For example, the outlet surface of
the filter support plate may include machined channels that correspond with the etched
or machined channels (or vertical through-holes of the metering/distribution plate).
Alternatively (or in addition to the channels) the outlet surface of the filter support
may include one or more cavities to facilitate the formation of one or more melt pools
of polymer material within the filter support plate that are to be directed to the
metering/distribution plate. When providing cavities within the filter support plate
to form melt pools, a valve plate is then provided between the filter support plate
and the metering/distribution plate and includes flow passages extending through the
valve plate that are in fluid communication with the melt pool(s) and the passages
of the metering/distribution plate.
[0080] Depending upon a particular application, a series of metering/distribution plates
could also be provided in the spin pack assembly of Figure 11 (as well as the spin
pack assembly of Figure 12), where the metering/distribution plates are arranged in
a vertically stacked alignment with respect to each other and include appropriately
aligned passages (i.e., channels and/or through-holes) to facilitate fluid communication
between two adjacent plates.
[0081] The spinneret includes orifices having different geometries, where the orifices can
include any two or more cross-sectional geometries and at any selected ratio of geometries
(e.g., spinneret 48 can be any of the types described above and depicted in Figures
5-9). A pump block 50, disposed above pack top 42, supports two metering pumps 52
and 54. The metering pumps deliver molten polymer through the pump block and to the
spin pack assembly, where the molten polymer is then filtered and directed to the
metering/distribution plate(s) for distribution and metering to the different shaped
spinneret orifices.
[0082] It is noted that, in certain embodiments, the pack top is not needed and thus does
not form part of the spin pack. Thus, the pack top in the assembly of Figure 11 (as
well as the embodiments of Figures 12 and 13) can be removed such that the filter
support plate lies directly below the pump block.
[0083] The flow channels through the various components of the two metering pump system
of Figure 11 can be designed such that one pump feeds one one type of spinneret orifice
(e.g. multi-lobal) and the other pump feeds another type of spinneret orifice (e.g.,
round). In this two metering pump embodiment, the pump speeds can be selected to largely
control metering of polymer material flowing through the metering/distribution plate
and spinneret, such that the metering/distribution plate serves primarily to distribute
the polymer to the different spinneret orifices. If more than two polymer components
(or two streams of the same polymer component including different additives) are desired
to form the mixed filaments, each additional component would require an extra metering
pump. The polymer temperatures fed to or from the two pumps may also be adjusted to
assist in acheiving desirable polymer conditions including, without limitation, enhanced
cross sections, suitable shear rates, etc. The metering/distribution plate can also
be used to distribute polymer from the filtration areas to the two types of spinneret
orifices. If the metering/distribution plate is manufactured by low cost techniques
such as etching, two or more plates may be selectively exchanged within the spin pack
assembly 40 to modify polymer flows to different spinneret orifices (resulting, e.g.,
in different fibers deniers) at a low cost and with relative ease.
[0084] In another embodiment depicted in Figure 12, a spin pack assembly 60 includes, in
a vertically stacked alignment, a pack top 62, a filter support plate 66 disposed
below the pack top, a filter formed between corresponding grooved portions of the
pack top and filter support plate to filter the polymer flowing through the assembly,
a metering/distribution plate 68 disposed below the filter support plate, and a spinneret
70 disposed below plate 68. The spinneret includes mixed orifice geometries and can
be of any suitable type (such as the types described above and depicted in Figures
5-9). A pump block 72 is disposed above the pack top and supports a single metering
pump 74 to deliver molten polymer to assembly 60. Fluid communication between the
filter support plate and the metering/distribution plate can be provided in any suitable
manner (e.g., similar to that described above for the embodiment of Figure 11).
[0085] During operation, polymer material is delivered by metering pump 74 into assembly
60, where the polymer material is filtered and then directed through the various passages
of the metering/distribution plate. The metering/distribution plate 68 is designed
in a suitable manner as described above to receive molten polymer from the filter
support plate 66, and to at least partially control the pressure drop of polymer flowing
to each spinneret orifice type. The control of the pressure drop through the metering/distribution
plate facilitates effective control of the denier of each of the mixed filament fibers
extruded from the spinneret.
[0086] A reference example is depicted in Figure 13 and includes a spin pack assembly 80
including, in a vertically stacked alignment, a pack top 82 that includes a filter
84 to filter molten polymer flowing through the assembly, a filter support plate 86
disposed below the pack top, and a spinneret 88 disposed below the filter support
plate. As in the previous embodiment depicted in Figure 12, a single metering pump
92, which is supported by pump block 90 disposed above pack top 82, delivers molten
polymer to assembly 80. However, assembly 80 does not include a metering/distribution
plate. Rather, a cavity 87 is formed within filter support plate 86 at a location
where the filter support plate engages the spinneret. The cavity 87 facilitates the
formation of a pressurized melt pool of molten polymer as polymer is delivered through
the filter to counterbores in the spinneret that lead to the various spinneret orifices.
Alternatively, it is noted that the cavity in which the melt pool forms could be provided
in the spinneret or both the filter support plate and the spinneret. In this reference
example, the vertically-extending capillaries or counterbores of the spinneret are
designed with suitable dimensions (e.g., suitable length to diameter ratios) to facilitate
the balance of pressure drops of polymer flow through the spinneret prior to emerging
from the spinneret orifices in a manner similar to that in which the metering/distribution
plate is designed as in the previous embodiments described above and depicted in Figures
11 and 12.
[0087] The reference example of Figure 13 is primarily suitable when the polymer pressure
within the melt pool remains at a specific value. Thus, while it is possible to provide
a spin pack assembly without the use of a metering/distribution plate to form the
mixed filament products as described herein (where the pressure drop, shear rate and
jet stretch is controlled by designing suitable channels and orifices in the spinneret),
the use of a metering/distribution plate to control pressure drop, which in turn enables
control of the deniers of the mixed filament fibers, is applicable to a much wider
range of applications and is thus preferable over spin pack assemblies that do not
employ such metering/distribution plates.
[0088] As noted above, etched (or machined) metering/distribution plates (such as the plate
depicted in Figures 10A and 10B) are effective in at least partially controlling pressure
drop to achieve the desired fiber size and denier of different shaped fibers. However,
as a reference example, metering/distribution plates can also be manufactured utilizing
a drilling process, where passages of varying cross-sectional dimensions arc formed
by drilling through the plate. In a drilled metering/distribution plate, there are
no horizontally extending channels such as in the etched (or machined) plate. Rather,
the passages of the drilled plate are generally vertical through-holes extending between
the top or inlet surface of the plate and the bottom or outlet surface of the plate.
A drilled metering plate typically requires a significant thickness to facilitate
a sufficient hole length to achieve the desired control of pressure drop through the
plate. In addition, different diameter holes can be used to control and adjust the
How rate through the drilled metering plate/spinneret combination to adjust the deniers
of the two types of fibers being spun from the same melt pool.
[0089] A reference example of a drilled metering/distribution plate 96 is depicted in Figures
14A and 14B. In this reference example, plate 96 has a suitable thickness to facilitate
the formation of through-holes of suitable lengths. The lengths and cross-sectional
dimensions of the through-holes (e.g., the length to diameter ratios of the through-holes)
can be selected in a similar manner as the channel dimensions in an etched (or machined)
metering/distribution plate to facilitate control of pressure drop of polymer flow
through the different shaped spinneret orifices, which in turn controls the deniers
of different shaped fibers.
[0090] For example, through-holes can be drilled in the plate of varying diameters (such
as through-holes 97 and 98 of plate 96 depicted in Figures 14A and 14B) to selectively
adjust the flow rate through the drilled metering plate/spinneret combination, which
in turn controls the deniers of the two types of filaments being spun from the same
metering pump and/or melt pool. By using different metering plates, different denier
ratios between the two types of spinneret orifices can be obtained without requiring
a new spinneret.
[0091] However, it is noted that drilled metering/distribution plates are significantly
more expensive to produce (e.g., as much as a tenfold or greater increase in cost)
than etched metering/distribution plates, due at least in part to the labor-intensive
requirements of drilling thousands of holes per meter along the surface of the plate.
In addition, since the drilled plate through-holes are vertically aligned, rather
than having a horizontal channel component as in the etched plates, controlling pressure
drop in different applications may require significant changes in the drilled plate
thicknesses. Thus, certain drilled plates can be very thick (and heavy), depending
upon certain applications that require certain through-hole dimensions. This renders
the drilled plates less suitable for exchanging or retrofitting within existing spin
pack assemblies. In contrast, etched metering/distribution plates with different channel
dimensions can be easily changed in an existing spin pack assembly while maintaining
generally the same thickness of the plate dimensions (since the horizontal etched
channel component is changed). In addition, due to their economic design, etched channel
plates can be disposable. Thus, the use of lower cost, etched metering/distribution
plates is preferred in the various spin pack assembly embodiments of the invention.
[0092] The combination of one or more metering/distribution plates and spinnerets with selective
orientations of orifice geometries in a spin pack system or assembly is highly effective
in producing a homogenous mixture of shaped fibers in the nonwoven fabrics and other
products described herein. As noted above, when utilizing a single spinneret with
different shaped orifices, it is extremely important to be able to at least partially
control the pressure drop upstream of the spinneret orifices to form fibers with mixed
geometries. The mass flow rate through each spinneret orifice type will be different
due to pressure drop differences as explained above. Further, at the same or similar
mass flow rate in each spinneret orifice type, the spinning characteristics are different
and do not lead to identical fiber diameter values. Therefore, the combination of
the above-described features for the spinneret and spin pack assembly render enhanced
control and production of fiber products including mixed filament geometries.
Spinning
[0093] The process of melt spinning is the most preferred embodiment for forming mixed filament
products described herein. In melt spinning, there is no intentional mass loss in
the extrudate. Solution spinning may be used for producing fibers from cellulose,
cellulosic derivatives, starch, and protein.
[0094] Spinning will typically occur at 100°C to about 350°C. The processing temperature
is determined by the chemical nature, molecular weights and concentration of each
component. Fiber spinning speeds of greater than 100 meters/minute are required. Preferably,
the fiber spinning speed is from about 500 to about 14,000 meters/minute. The spinning
may involve direct spinning, using techniques such as spunlaid or meltblown, as long
as the fibers are mostly continuous in nature. Continuous fibers are hereby defined
as having length to width ratio greater than about 2500:1.
[0095] The fibers and fabrics made in the present invention often contain a finish applied
after formation to improve performance or tactile properties. These finishes typically
are hydrophilic or hydrophobic in nature and are used to improve the performance of
articles containing the finish. For example, Goulston Technologies' Lurol 9519 can
be used with polypropylene and polyester to impart a semi-durable hydrophilic finish.
[0096] Figure 15 depicts a schematic of a typical spunbond line 100 utilizing a single polymer
source. In this embodiment, any combination of the above described metering/distribution
plates, melt pools and/or spinnerets may be employed (e.g., the types of systems described
above and depicted in Figures 5-10, 12 and 13) in the spin pack assembly 118. Briefly,
the spunbond system includes a hopper 110 into which pellets of polymer are placed.
The polymer is fed from hopper 110 to a screw extruder 112, where the polymer is melted.
The molten polymer flows through heated pipe 114 into metering pump 116 and spin pack
assembly 118, including a spinneret 120 with orifices through which fibers 122 are
extruded. The extruded fibers 122 are quenched with a quenching medium 124 (e.g.,
air), and are subsequently directed into a drawing unit 126 (e.g., aspirator). Upon
exiting the drawing unit 126, the attenuated fibers 128 are laid down upon a continuous
screen belt 130 supported and driven by rolls 132 and 134. The screen belt conveys
the prebonded web of fibers from the lay down location to calendar rolls 144 and 146.
The extruder and melt pumps are chosen based on the polymers desired.
[0097] While system 100 utilizes a single melt/metering pump, an alternative system can
employ two or more metering pumps (e.g., for use with the spin pack assembly of Figure
11). In addition, system 100 may be used with a single polymer or a blend of polymers.
Equipment Examples
[0098] A spin pack assembly including an etched metering/distribution plate (MDP) and having
a configuration similar to the assembly described above and depicted in Figure 12
was used in conducting each of the four examples described below, with results tabulated
in Tables 1 and 2. The assembly included a mixed filament spinneret including 20,000
orifices of multi-lobal and solid round geometric configurations. In particular, the
multi-lobal fibers of Examples 1-3 are trilobal fibers (e.g., similar to the fiber
depicted in Figure 3A), while the multi-lobal fibers of Example 4 are cross-shaped
fibers having four lobes (e.g., similar to the fiber depicted in Figure 3B). A fiber
spinning speed was set for each example at 4,000 meters per minute (MPM).
[0099] In each example, a different MDP was utilized in the spin pack assembly, where the
horizontally etched MDP channel dimensions (length, width, depth) that lead to each
of the multi-lobal and round spinneret orifices were modified. The MDP channels were
desiged to yield equal residence times for the polymer material flowing through the
spinneret orifices. Table 1 tabulates the MDP channel and spinneret orifice dimensional
information for forming the multi-lobal fibers of each example, as well as the calculated
total pressure drop (i.e., pressure drop through the MDP and the spinneret orifice),
shear rate, jet stretch, denier per fiber (dpf) and fiber size for these fibers. Table
2 tabulates the same information for the round fibers that are formed in each example.
Table 1: Multi-lobal Fibers
|
Example 1 |
Example 2 |
Example 3 |
Example 4 |
Spin Speed (MPM) |
4000 |
4000 |
4000 |
4000 |
Polymer |
PP |
PP |
PET |
PP |
Fiber Cross-section |
Tri-lobal |
Tri-lobal |
Tri-lobal |
Cross |
# of Filaments |
16000 |
16000 |
16000 |
16000 |
MDP channel dimensions (mm) |
width: 0.7 |
width: 0.7 |
width: 0.7 |
width: 0.7 |
depth: 0.381 |
depth: 0.381 |
depth: 0.381 |
depth: 0.381 |
length: 11.69 |
length: 9 |
length: 22.6 |
length: 9.9 |
Spinneret Orifice dimensions (mm) |
Leg L: 0.1705 |
LegL: 0.1705 |
LegL: 0.1705 |
Leg L: 0.18 |
Leg W: 0.127 |
Leg W: 0.127 |
Leg W: 0.127 |
Leg W: 0.125 |
Area: 0.082 |
Area: 0.082 |
Area: 0.082 |
Area: 0.099 |
Total Pressure Drop (psi) |
750 |
750 |
750 |
750 |
Fiber Size (g/hole/min) |
0.67 |
0.89 |
0.67 |
0.89 |
Denier (dpf) |
1.5 |
2 |
1.5 |
2 |
Shear rate |
5733 |
7644 |
3822 |
6125 |
Jet velocity (MPM) |
10.4 |
13.9 |
6.95 |
8.63 |
Jet stretch |
384 |
288 |
576 |
463 |
Table 2: Solid Round Fibers
|
Example 1 |
Example 2 |
Example 3 |
Example 4 |
Spin Speed (MPM) |
4000 |
4000 |
4000 |
4000 |
Polymer |
PP |
PP |
PET |
PP |
# of Filaments |
4000 |
4000 |
4000 |
4000 |
MDP channel dimensions (mm) |
width: 0.7 |
width: 0.7 |
width: 0.7 |
width: 0.7 |
depth: 0.381 |
depth: 0.381 |
depth: 0.381 |
depth: 0.381 |
length: 11.3 |
length: 16.79 |
length: 22.3 |
length: 16.8 |
Spinneret Orifice dimensions (mm) |
diameter: 0.35 |
diameter: 0.35 |
diameter: 0.35 |
diameter: 0.35 |
length: 1.4 |
length: 1.4 |
length: 1.4 |
length: 1.4 |
Total Pressure Drop (psi) |
750 |
750 |
750 |
751 |
Fiber Size (g/hole/min) |
0.67 |
0.44 |
0.67 |
0.44 |
Denier (dpf) |
1.5 |
1 |
1.5 |
1 |
Shear rate |
3381 |
2254 |
2254 |
2254 |
Jet velocity (MPM) |
8.88 |
5.92 |
3.95 |
8.63 |
Jet stretch |
450 |
675 |
1013 |
463 |
[0100] As can be seen from the tabulated information, the spin pack assembly of Examples
1-3 utilizes the same spinneret, which has a 75:25 ratio of trilobal to round fibers.
The spinneret used for Example 4 is different from the previous examples in that the
orifices are cross-shaped, with a 75:25 ratio of cross-shaped fibers to round fibers.
In addition, a single molten polymer material, either polypropylene (PP) or polyethylene
terephthalate (PET), is utilized to form both the round and multi-lobal fibers of
each example. Example 1 serves as a reference, while certain modifications are made
to the equipment and/or polymer materials in each of Examples 2-4 for comparison purposes
with Example 1.
[0101] In a comparison of Example 1 and Example 2, the channel dimensions of the MDP are
modified in Example 2 for both the trilobal and round fibers so as to modify the dpf
of the fibers. This demonstrates the ease with which fiber denier values can be modified
by replacing one MDP with another MDP having different channel dimensions.
[0102] In comparing Example 1 with Example 3, the polymer material used to form the fibers
is changed from polypropylene to polyethylene terephthalate. However, due to the change
in MDP channel dimensions, the denier per fiber for each of the round and trilobal
fibers is maintained at the same value. This example demonstrates that, when a change
in polymer material and/or rheology occurs, the MDP channel dimensions can be selectively
adjusted (e.g., by replacing one etched MDP with another etched MDP in the spin pack
assembly) to maintain fiber deniers at desired values.
[0103] As noted above, the spinneret of the assembly is changed in Example 4, where the
trilobal spinneret orifices are replaced with cross-shaped spinneret orifices. This
example illustrates that the MDP channel dimensions can be easily changed (e.g., by
switching plates) to effectively control pressure drop and fiber denier while allowing
more flexibility in spinneret orifice designs and dimensions.
[0104] While a drilled MDP as a reference example, could also be utilized in each of these
examples, it is preferable to utilize an etched MDP for all of the reasons noted above
(e.g., costs, greater flexibility in channel dimensions for a spin pack assembly having
specified dimensions, etc.).
(6) Articles
[0105] The spunmelt fibrous fabrics formed in accordance with the present invention are
nonwoven webs. The fibrous fabric may comprise one or more layers. If the fibrous
fabric contains more than one layer, the layers are typically consolidated by thermal
point-bonding or other techniques to attain strength, integrity and certain aesthetic
characteristics. A layer is part of (or all of) a fibrous fabric that is produced
in a separate fiber lay down or forming step and will have the same fibers intimately
mixed throughout the layer. A laminate is defined as a two or more nonwoven layers
contacting along at least a portion of their respective planar faces with or without
interfacial mixing. A fibrous fabric may contain one or more laminates. In a spunlaid
or meltblown process, the fibers are consolidated using industry standard spunbond
type technologies. Typical bonding methods include, but are not limited to, calender
(pressure and heat), thru-air heat, mechanical entanglement, hydraulic entanglement,
needle punching, and chemical bonding and/or resin bonding. Thermally bondable fibers
are required for the pressurized heat and thru-air heat bonding methods. Fibers may
also be woven together to form yarns and other fiber products.
[0106] The mixture of shaped fibers of the present invention may also be bonded or combined
with thermoplastic or non-thermoplastic nonwoven webs or with film webs to make various
articles. The polymeric fibers, typically synthetic fibers, or non-thermoplastic polymeric
fibers, often natural fibers, may be used in discrete layers. Suitable synthetic fibers
include, without limitation, fibers made from polyolefins such as polyethylene and
polypropylene, polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate
(PEN), polytrimethylene terephthalate (PTT) and polybutylene terephthalate (PBT),
polyactic acid, polyurethanes, polycarbonates, polyamides such as Nylon 6, Nylon 6,6
and Nylon 6,10, polyacrylates, and copolymers thereof as well as mixtures thereof.
Natural fibers include lyocell and cellulosic fibers and derivatives thereof. Suitable
cellulosic fibers include those derived from any tree or vegetation, including hardwood
fibers, softwood fibers, hemp, and cotton. Also included are fibers made from processed
natural cellulosic resources such as rayon.
[0107] The single layer of shaped fibers of the present invention may be utilized by itself
in an article, or the layer may be combined with other nonwoven layers or a film layer
to produce a laminate. Examples of suitable laminates include, but are not limited
to spunbond-meltblown-spunbond laminates. Because of the higher opacity and control
over the mechanical properties, a spunbond layer of shaped fibers may have a lower
basis weight than a typical spunbond layer made of only solid round fibers, but still
provide the same opacity and mechanical properties as the higher basis weight solid
round fiber layer. Alternatively, a shaped fiber layer may be utilized which enables
the basis weight or denier of the meltblown layer to be reduced or can eliminate the
need for a meltblown layer. A spunbond layer of the shaped fibers of the present invention
can also be used in a spundbond-nanofiber-spundbond laminate. The shaped fiber layer
can be used as both spunbond layers or only as one spunbond layer. Each separate layer
in a nonwoven is identified as a layer that is produced with a different composition
of fibers. As described in the present invention, a single layer may have a combination
of different fiber shapes, diameter, configuration, and compositions. The shaped fiber
nonwoven layer may also be combined with a film web. These laminates are useful as
backsheet and other barriers on disposable nonwoven articles.
[0108] The shaped fibers of the present invention may be used to make nonwovens, among other
suitable articles. Nonwoven or fibrous fabric articles are defined as articles that
contain greater than 15% of a plurality of fibers that are non-continuous or continuous
and physically and/or chemically attached to one another. The nonwoven may be combined
with additional nonwovens or films to produce a layered product used either by itself
or as a component in a complex combination of other materials, such as a baby diaper
or feminine care pad. Preferred articles are disposable, nonwoven articles. The resultant
products may find use in filters for air, oil and water; vacuum cleaner filters; furnace
filters; face masks; coffee filters, tea or coffee bags; thermal insulation materials
and sound insulation materials; nonwovens for one-time use sanitary products such
as diapers, feminine pads, and incontinence articles; biodegradable textile fabrics
for improved moisture absorption and softness of wear such as micro fiber or breathable
fabrics; an electrostatically charged, structured web for collecting and removing
dust; reinforcements and webs for hard grades of paper, such as wrapping paper, writing
paper, newsprint, corrugated paper board, and webs for tissue grades of paper such
as toilet paper, paper towel, napkins and facial tissue; medical uses such as barrier
products, surgical drapes, wound dressing, bandages, dermal patches and self-dissolving
sutures; and dental uses such as dental floss and toothbrush bristles. The fibrous
web may also include odor absorbents, termite repellants, insecticides, rodenticides,
and the like, for specific uses. The resultant product absorbs water and oil and may
find use in oil or water spill clean-up, or controlled water retention and release
for agricultural or horticultural applications. The resultant fibers or fiber webs
may also be incorporated into other materials such as saw dust, wood pulp, plastics,
and concrete, to form composite materials, which can be used as building materials
such as walls, support beams, pressed boards, dry walls and backings, and ceiling
tiles; other medical uses such as casts, splints, and tongue depressors; and in fireplace
logs for decorative and/or burning purpose. Preferred articles of the present invention
include disposable nonwovens for hygiene applications, such as facial cloths or cleansing
cloths, and medical applications. Hygiene applications include wipes, such as baby
wipes or feminine wipes; diapers, particularly the top sheet, leg cuff, ear, side
panel covering, back sheet or outer cover; and feminine pads or products, particularly
the top sheet. Other preferred applications are wipes or cloths for hard surface cleansing.
The wipes may be wet or dry.
Continuous Fiber Examples
[0109] The Examples below further illustrate the present invention. A polypropylene was
purchased from ATOFINA as FINA 3860X. Two polypropylenes were purchased from Basell,
Profax PH-835 and PDC-1274. A polyethylene was purchased from Dow Chemical as Aspun
6811A. Two polyester resins were purchased from Eastman Chemical Company as Eastman
F61HC as a PET and Eastman 14285 as a coPET. The meltblown grade resin polypropylene
was purchased from Exxon Chemical Company as Exxon 3456G.
[0110] The opacity measurements shown are made on an Opacimeter Model BNL-3 Serial Number
7628. Three measurements are made on one specimen with an average of three specimens
for each material used.
Comparative Examples: 100% solid round, hollow round or trilobal
[0111] A polypropylene spunbond fabric is produced from Basell PH-835, except for examples
C13-15 which are produced from FINA 3860X. C1-C7 and C13-C33 have a through-put per
hole of 0.4ghm. C8-C12 have a through-put per hole of 0.65ghm. The shape of the fiber
is indicated in the table as solid round (SR), hollow round (HR) and trilobal (TRI).
All comparative examples are using 2016 hole spinneret. The fibers are attenuated
to an average fiber diameter or denier indicated in the table below. These fibers
are thermally bonded together using heat and pressure. The following nonwoven fabrics
are produced, basis weight determined, and the opacity and/or CD tensile strength
of the nonwoven is measured on the samples.
Table 3: Comparative Opacity
No. |
Shape |
Basis Weight (gsm) |
Fiber Diameter (µm) |
Fiber Denier (dpf) |
Opacity (%) |
C1 |
SR |
25 |
15.3 |
1.5 |
25.4 |
C2 |
SR |
17 |
15.3 |
1.5 |
18.2 |
C3 |
SR |
10 |
15.3 |
1.5 |
10.5 |
C4 |
SR |
17 |
14 |
1.25 |
18.7 |
C5 |
SR |
25 |
14 |
1.25 |
26.4 |
C6 |
SR |
17 |
12.5 |
1.0 |
19.7 |
C7 |
SR |
17 |
11.2 |
0.8 |
20.9 |
C8 |
SR |
26 |
14 |
1.25 |
26.4 |
C9 |
SR |
24 |
14 |
1.25 |
23.8 |
C10 |
SR |
18 |
14 |
1.25 |
18.5 |
C11 |
SR |
21 |
16 |
1.62 |
18.5 |
C12 |
SR |
26 |
16 |
1.62 |
23.8 |
C13 |
SR |
21 |
13 |
1.07 |
21.7 |
C14 |
SR |
18 |
13 |
1.07 |
18.8 |
C15 |
SR |
17 |
13 |
1.07 |
16.4 |
C16 |
HR |
25 |
- |
1.25 |
33.3 |
C17 |
HR |
17 |
- |
1.25 |
26.0 |
C18 |
HR |
10 |
- |
1.25 |
16.3 |
C19 |
TRI |
25 |
- |
1.25 |
41.8 |
C20 |
TRI |
17 |
- |
1.25 |
34.0 |
C21 |
TRI |
10 |
- |
1.25 |
21.6 |
Table 4: Comparative Mechanical Properties
No. |
Shape |
Basis Weight (gsm) |
Fiber Denier (dpf) |
Maximum CD Tensile Strength (g/in) |
C22 |
SR |
25 |
1.5 |
1370 |
C23 |
SR |
25 |
1.25 |
1590 |
C24 |
SR |
17 |
1.5 |
1170 |
C25 |
SR |
17 |
1.25 |
1045 |
C26 |
SR |
17 |
0.8 |
950 |
C27 |
SR |
10 |
1.5 |
530 |
C28 |
HR |
25 |
1.25 |
2040 |
C29 |
HR |
17 |
1.25 |
1310 |
C30 |
HR |
10 |
1.25 |
630 |
C31 |
TRI |
25 |
1.25 |
810 |
C32 |
TRI |
17 |
1.25 |
760 |
C33 |
TRI |
10 |
1.25 |
470 |
Examples:
Example 5: Fibrous web containing mixture of hollow round, solid round and trilobal
opacity and mechanical properties.
[0112] A polypropylene spunbond fabric is produced using solid round (SR), hollow round
(HR) and trilobal fibers (TRI) made from Basell PH-835. A special spinneret is used
that contains a mixture of fiber shapes and a metering plate to feed polymer to each
orifice. The through-put per holes is 0.4ghm using 2016 hole spinneret. The fibers
are attenuated to an average fiber diameter or denier indicated in the table. The
fibers are thermally bonded together using heat and pressure. The following nonwoven
fabrics are produced, basis weight determined, and the opacity and/or CD tensile strength
of the nonwoven is measured on the samples.
Table 5: Examples of shaped fiber web and opacity and mechanical properties
Basis Weight (gsm) |
Fiber Ratio |
Fiber Denier (dpf) |
Opacity (%) |
Maximum CD Strength (g/in) |
|
SR |
HR |
TRI |
SR |
HR |
TRI |
|
|
25 |
80 |
10 |
10 |
1.25 |
1.25 |
1.25 |
28.6 |
1560 |
25 |
60 |
20 |
20 |
1.25 |
1.25 |
1.25 |
30.9 |
1520 |
25 |
40 |
30 |
30 |
1.25 |
1.25 |
1.25 |
33.1 |
1500 |
25 |
20 |
40 |
40 |
1.25 |
1.25 |
1.25 |
35.3 |
1460 |
25 |
10 |
45 |
45 |
1.25 |
1.25 |
1.25 |
36.4 |
1450 |
17 |
80 |
10 |
10 |
1.25 |
1.25 |
1.25 |
21.0 |
1040 |
17 |
60 |
20 |
20 |
1.25 |
1.25 |
1.25 |
23.2 |
1040 |
17 |
40 |
30 |
30 |
1.25 |
1.25 |
1.25 |
25.5 |
1040 |
17 |
20 |
40 |
40 |
1.25 |
1.25 |
1.25 |
27.7 |
1040 |
17 |
10 |
45 |
45 |
1.25 |
1.25 |
1.25 |
28.9 |
1040 |
10 |
80 |
10 |
10 |
1.25 |
1.25 |
1.25 |
11.0 |
510 |
10 |
60 |
20 |
20 |
1.25 |
1.25 |
1.25 |
13.0 |
520 |
10 |
40 |
30 |
30 |
1.25 |
1.25 |
1.25 |
15.0 |
530 |
10 |
20 |
40 |
40 |
1.25 |
1.25 |
1.25 |
17.0 |
540 |
10 |
10 |
45 |
45 |
1.25 |
1.25 |
1.25 |
18.0 |
545 |
25 |
90 |
0 |
10 |
1.25 |
- |
1.25 |
27.9 |
1510 |
25 |
50 |
0 |
50 |
1.25 |
- |
1.25 |
34.1 |
1200 |
25 |
10 |
0 |
90 |
1.25 |
- |
1.25 |
40.3 |
900 |
17 |
90 |
0 |
10 |
1.25 |
- |
1.25 |
32.5 |
790 |
17 |
50 |
0 |
50 |
1.25 |
- |
1.25 |
26.4 |
900 |
17 |
10 |
0 |
90 |
1.25 |
- |
1.25 |
20.2 |
1020 |
10 |
90 |
0 |
10 |
1.25 |
- |
1.25 |
10.3 |
490 |
10 |
50 |
0 |
50 |
1.25 |
- |
1.25 |
15.3 |
490 |
10 |
10 |
0 |
90 |
1.25 |
- |
1.25 |
20.3 |
470 |
25 |
0 |
90 |
10 |
- |
1.25 |
1.25 |
34.2 |
1920 |
25 |
0 |
50 |
50 |
- |
1.25 |
1.25 |
37.6 |
1425 |
25 |
0 |
10 |
90 |
- |
1.25 |
1.25 |
41.0 |
930 |
17 |
0 |
90 |
10 |
- |
1.25 |
1.25 |
26.8 |
1255 |
17 |
0 |
50 |
50 |
- |
1.25 |
1.25 |
30.0 |
1033 |
17 |
0 |
10 |
90 |
- |
1.25 |
1.25 |
33.2 |
815 |
10 |
0 |
90 |
10 |
- |
1.25 |
1.25 |
16.8 |
610 |
10 |
0 |
50 |
50 |
- |
1.25 |
1.25 |
19.0 |
550 |
10 |
0 |
10 |
90 |
- |
1.25 |
1.25 |
21.1 |
490 |
25 |
90 |
10 |
0 |
1.25 |
1.25 |
- |
27.1 |
1630 |
25 |
50 |
50 |
0 |
1.25 |
1.25 |
- |
29.9 |
1815 |
25 |
10 |
90 |
0 |
1.25 |
1.25 |
- |
32.6 |
1995 |
17 |
90 |
10 |
0 |
1.25 |
1.25 |
- |
19.4 |
1070 |
17 |
50 |
50 |
0 |
1.25 |
1.25 |
- |
22.4 |
1180 |
17 |
10 |
90 |
0 |
1.25 |
1.25 |
- |
25.3 |
1280 |
10 |
90 |
10 |
0 |
1.25 |
1.25 |
- |
9.7 |
510 |
10 |
50 |
50 |
0 |
1.25 |
1.25 |
- |
12.7 |
670 |
10 |
10 |
90 |
0 |
1.25 |
1.25 |
- |
15.6 |
620 |
Example 6: Fibrous webs containing two polymers and two shapes
[0113] A spunbond machine is set-up to run polypropylene at 220°C or polyester at 290°C.
A spinneret as shown in Figures 9A and 9B may be used to produce the fibers. A metering
system with two melt pumps may be used to control each polymer type and melt flow.
Nonwovens can be produced at a range of mass flow ratios and deniers. Any combination
of polymers and shapes may be used. For example, Basell PH-835 solid round fibers
may be combined with Dow Aspun 6811A and/or Eastman F61HC trilobal fibers. Alternatively,
the Basell PH-835 could be used to make trilobal fibers and hollow round fibers made
of ATOFINA 3860X.
Example 7: Fibrous webs containing two polymers and two shapes and a meltblown layer
[0114] The fibrous fabric of Example 6 is made and combined with a polypropylene meltblown
layer made from Exxon 3546G. The average meltblown diameter is 3 microns at a through-put
of 0.6 ghm. The two layers can be thermally bonded together or hydroentangled or combined
with other bonding methods.
Example 8: Fibrous webs containing one polymer and two shapes
[0115] A fibrous web is produced with solid round meltblown diameter fibers supplied at
0.15 ghm and trilobal spunlaid diameter fiber supplied at 0.4 ghm. In another embodiment,
a solid round spunlaid diameter fiber is also produced in the same layer to create
a three-fiber layer.
Example 9: Fibrous web containing a mixture of multicomponent solid round and multicomponent
trilobal fibers
[0116] A spunbond nonwoven is produced containing a 50/50 weight percent mixture of multicomponent
solid round and multicomponent trilobal fibers. The multicomponent solid round fibers
are sheath and core with a 50/50 weight percent ratio of ATOFINA 3860X as the sheath
material and Basell Profax PH-835 as the core. The solid round fibers are attenuated
to a range of diameters down to 1.0 dpf, depending on the mass throughput per capillary.
The trilobal fibers are composed of a 20/80 weight percent ratio of ATOFINA as the
trilobal tip material and Basell Profax PH-835 as the core. The trilobal fibers are
attenuated to a range of diameters down to 1.0 dpf, depending on the mass throughput
per capillary. These fibers are then consolidated together using conventional bonding
methods, most commonly thermal point bonding, but hydroentangling can also be used.
Basis weight down to 5 gsm can be produced. If desired, a polypropylene meltblown
layer can be produced using Exxon 3546G. The average meltblown diameter is 3 microns
at a through-put of 0.6 ghm. The meltblown layer is then combined with the spunlaid
layer either by direct collection or brought in from a second source. Other alternate
layers can be added. The fibers are thermally bonded together using heat and pressure.
This nonwoven has high opacity characteristics with improved strength due to the presence
of the lower molecular weight ATOFINA 3860X outer component of the multicomponent
fibers. The component ratio of individual fibers can be changed to further adjust
the strength and the ratio of shaped fibers can be changed to alter the opacity and
strength, as needed for a desired application.
Example 10: Fibrous web containing a mixture of multicomponent solid round and multicomponent
trilobal fibers plus mixed meltblown diameter
[0117] A spunbond nonwoven is produced containing a 45/45/10 weight percent mixture of multicomponent
solid round, multicomponent trilobal fibers, and meltblown diameter fibers. The multicomponent
solid round fibers are sheath and core with a 50/50 weight percent ratio of ATOFINA
3860X as the sheath material and Basell Profax PH-835 as the core. The solid round
fibers are attenuated to a range of diameters down to 1.0 dpf, depending on the mass
throughput per capillary. The trilobal fibers are composed of a 20/80 weight percent
ratio of ATOFINA as the trilobal tip material and Basell Profax PH-835 as the core.
The trilobal fibers are attenuated to a range of diameters down to 1.0 dpf, depending
on the mass throughput per capillary. The solid round and trilobal spunbond orifice
are supplied a polymer at 0.4 ghm, while the meltblown diameter orifices are supplied
polymer at 0.15 ghm. All of these fibers are extruded from an etched metering plate
and spinneret. The meltblown diameter fibers have an average diameter of 6 microns.
These fibers are then consolidated together using conventional bonding methods. This
nonwoven also has high opacity characteristics with improved strength due to the presence
of the lower molecular weight ATOFINA 3860X outer component of the multicomponent
fibers. The component ratio in individual fibers can be changed to further adjust
the strength and the ratio of shaped fibers can be changed to alter the opacity and
strength, as needed for a desired application.
Example 11: Fibrous web containing a mixture of multicomponent solid round, monocomponent
trilobal fibers, and meltblown diameter fibers.
[0118] A spunbond nonwoven is produced containing a 20/70/10 weight percent mixture of multicomponent
solid round, monocomponent trilobal fibers and meltblown diameter fibers. The multicomponent
solid round fibers are a 75/25 weight percent ratio of Eastman F61HC polyester as
the core material and Eastman 14285 as the sheath material. The multicomponent round
fibers are attenuated to a range of diameters down to 1.0 dpf, depending on the mass
throughput per capillary. The monocomponent trilobal fibers are composed of Eastman
F61HC. The polyester meltblown fibers are produced using an Eastman F33HC. The monocomponent
trilobal fibers are attenuated to a range of sizes down to 1.0 dpf, depending on the
mass throughput per capillary. The average meltblown diameter is 3 microns at a through-put
of 0.6 ghm. This construction is used to produce a high strength and loft polyester
spunbond. The component ratio in individual fibers and between fiber types can be
changed to further alter the opacity and strength, as needed for a desired application.
Example 12: Fibrous web containing a mixture of multicomponent solid round and monocomponent
trilobal fibers.
[0119] A spunbond nonwoven is produced containing a 20/70/10 weight percent mixture of multicomponent
solid round, monocomponent trilobal fibers and meltblown diameter fibers from the
same spinneret. Alternatively, a spunbond nonwoven can be produced containing a 30/70
weight percent mixture of multicomponent solid round and monocomponent trilobal fibers.
The multicomponent solid round fibers are a 75/25 weight percent ratio of Eastman
F61HC polyester as the core material and Eastman 14285 as the sheath material. The
multicomponent round fibers are attenuated to a range of diameters down to 1.0 dpf,
depending on the mass throughput per capillary. The monocomponent trilobal fibers
are composed of Eastman F61HC. If present, the polyester meltblown fibers are produced
using an Eastman F33HC. The monocomponent trilobal fibers are attenuated to a range
of sizes down to 1.0 dpf, depending on the mass throughput per capillary. The average
meltblown diameter is 6 microns at a through-put of 0.15 ghm. The nonwoven web with
shaped fibers may be combined with a meltblown layer. Other alternate layers can be
added.
[0120] Many examples have been shown and given here to demonstrate the various equipment
embodiments, methods of forming mixed fiber products having different geometries and
the breadth of fibers that can be produced to illustrate the invention.
[0121] While particular embodiments of the present invention have been illustrated and described,
it would be obvious to those skilled in the art that various other changes and modifications
can be made without departing from the scope of the invention. It is intended to cover
in the appended claims all such changes and modifications that are within the scope
of the invention.
1. A spin pack assembly comprising:
a spinneret comprising a first set of spinneret orifices and a second set of spinneret
orifices, the spinneret orifices of the first set having geometries different from
geometries of the spinneret orifices of the second set; and
a metering/distribution plate configured to deliver molten polymer flowing through
the spin pack assembly to the spinneret, wherein the metering/distribution plate comprises:
a first set of passages configured to deliver molten polymer flowing through the spin
pack assembly to the first set of spinneret orifices; and
a second set of passages configured to deliver molten polymer flowing through the
spin pack assembly to the second set of spinneret orifices;
wherein the passages of the plate include horizontally formed channels disposed along
a first surface of the plate and vertical through-holes in fluid communication with
the horizontally formed channels and extending to a second surface of the plate, the
passages for each set are selected to facilitate the formation of extruded fibers
through the first and second sets of spinneret orifices having selected deniers, and
the metering/distribution plate serves a metering function in that each passage that
corresponds with a respective spinneret orifice is selectively dimensioned so as to
control the pressure drop of the polymer flowing through the passage and thus the
delivery of polymer at a desired flow rate to the respective spinneret orifice.
2. The spin pack assembly of claim 1, wherein the channels have a channel width to a
channel depth ratio of about 1.5:1 to about 15:1.
3. The spin pack assembly of any of claims I to 2, wherein the metering/distribution
plate is made using an etching process to form the passages of the plate.
4. The spin pack assembly of any of claims 1 to 3, further comprising a plurality of
metering/distribution plates configured to deliver molten polymer flowing through
the spin pack assembly to the spinneret.
5. The spin pack assembly of any of claims 1 to 4, wherein the geometries of the spinneret
orifices include round and multi-lobal.
6. The spin pack assembly of any of claims 1 to 5, wherein the spin pack assembly is
configured to receive different metering/distribution plates including different sets
of passages having different passage dimensions.
7. The spin pack assembly of any of claims 1 to 6, wherein at least one spinneret orifice
has a geometry that is configured to form a hollow fiber.
8. The spin pack assembly of claim 5, wherein the geometries of the spinneret orifices
include trilobal.
9. The spin pack assembly of claim 5, wherein at least some of the round spinneret orifices
are located closer to peripheral portions of the spinneret in relation to all multi-lobal
spinneret orifices.
10. The spin pack assembly of claim 5, wherein only round spinneret orifices are located
within a selected section disposed at each longitudinal end portion of the spinneret.
11. The spin pack assembly of claim 5, wherein only round spinneret orifices are located
within a central portion of the spinneret.
12. The spin pack assembly of claim 5, wherein at least one group of the multi-lobal spinneret
orifices are formed along an outlet surface the spinneret such that a lobe of a multi-lobal
fiber extruded from each multi-lobal spinneret orifice of the at least one group is
aligned to face in a direction of a quench medium source that directs a quench medium
toward fibers extruded from the spinneret.
13. The spin pack assembly of claim 5, wherein the spinneret includes a first group of
multi-lobal spinneret orifices and a second group of multi-lobal spinneret orifices
that have the same geometric shape as the first group of multi-lobal spinneret orifices,
the multi-lobal orifices of the first group are aligned along an outlet surface of
the spinneret at a selected angle of rotation with respect to the multi-lobal spinneret
orifices of the second group.
14. The spin pack assembly of claim 13, wherein the multi-lobal spinneret orifices of
the first group are aligned at a 180° rotation with respect to the multi-lobal spinneret
orifices of the second group.
15. The spin pack assembly of any of claims 1 to 14, wherein at least 50% of the spinneret
orifices have a multi-lobal geometry.
16. The spin pack assembly of any of claims 1 to 14, wherein at least 75% of the spinneret
orifices have a multi-lobal geometry.
17. The spin pack assembly of any of claims 1 to 14, wherein at least 80% of the spinneret
orifices have a multi-lobal geometry.
18. A method of forming a mixed filament product including polymer fibers with different
cross-sectional geometries, the method comprising:
providing a spin pack assembly as claimed in any of claims 1 to 17.
19. The method of claim 18, wherein the geometries of the spinneret orifices include round
and multi-lobal.
20. The method of claim 19, wherein at least one group of the multi-lobal spinneret orifices
are formed in the spinneret such that a lobe of a multi-lobal fiber extruded from
each multi-lobal spinneret orifice of the at least one group is aligned to face in
a direction of a quench medium source that directs a quench medium toward fibers extruded
from the spinneret.
21. The method of claim 18, further comprising:
providing the passages of the first set of the metering/distribution plate with selected
dimensions to control the deniers of fibers extruded from the first set of spinneret
orifices; and
providing the passages of the second set of the metering/distribution plate with selected
dimensions to control the deniers of fibers extruded from the second set of spinneret
orifices.
22. The method of any of claims 18 to 21, further comprising:
modifying at least one operating parameter selected from: polymer throughput through
the spin pack assembly, fiber cross-sectional geometry of fibers formed from the spinneret,
the arrangement of spinneret orifices along the spinneret, a temperature of polymer
material flowing through the spin pack assembly, denier of fibers formed from at least
one of the first and second sets of spinneret orifices, the number of spinneret orifices
in at least one of the first and second sets of spinneret orifices, and polymer material
of fibers extruded from the spinneret; and
replacing the metering/distribution plate in the spin pack assembly with a different
metering/distribution plate including selected passage dimensions to facilitate selective
control of the deniers of fibers extruded from the spinneret after the modification
of the at least one operating parameter.
23. The method of any of claims 18 to 22, wherein fibers formed from the spinneret include
at least one of: fibers having different cross-sectional geometries but with the same
one or more polymer components, and fibers having different cross-sectional geometries
and different polymer components.
24. The method of any of claims 18 to 23, wherein at least some of the fibers formed from
the spinneret include multi-polymer components.
25. A spunlaid system comprising:
a spin pack assembly as claimed in any of claims 1 to 17; and
a quench source aligned and configured to direct at least one source of quench medium
toward fibers extruded from the spinneret.
26. The system of claim 25, wherein at least one group of the multi-lobal spinneret orifices
are formed along an outlet surface the spinneret such that a lobe of a multi-lobal
fiber extruded from each multi-lobal spinneret orifice of the at least one group is
aligned to face in a direction of a quench medium source that directs a quench medium
toward fibers extruded from the spinneret.
27. The system of claim 25 or 26, further comprising:
a plurality of metering pumps to independently meter molten polymer material to the
spin pack assembly.
28. The system of claim 27, wherein a first metering pump meters a molten polymer material
to the first set of passages of the metering/distribution plate, and a second metering
pump meters molten polymer material to the second set of passages of the metering/distribution
plate.
1. Spinnpaketanordnung, die aufweist:
eine Spinndüse, die einen ersten Satz von Spinndüsenmündungen und einen zweiten Satz
von Spinndüsenmündungen aufweist, wobei die Spinndüsenmündungen des ersten Satzes
Geometrien haben, die sich von Geometrien der Spinndüsenmündungen des zweiten Satzes
unterscheiden; und
eine Dosier-/Verteilungsplatte, die aufgebaut ist, um geschmolzenes Polymer, das durch
die Spinnpaketanordnung fließt, an die Spinndüse zuzuführen, wobei die Dosier-/Verteilungsplatte
aufweist:
einen ersten Satz von Durchgängen, die aufgebaut sind, um geschmolzenes Polymer, das
durch die Spinnpaketanordnung fließt, an den ersten Satz von Spinndüsenmündungen zuzuführen;
und
einen zweiten Satz von Durchgängen, die aufgebaut sind, um geschmolzenes Polymer,
das durch die Spinnpaketanordnung fließt, an den zweiten Satz von Spinndüsenmündungen
zuzuführen;
wobei die Durchgänge der Platte horizontal ausgebildete Kanäle, die entlang einer
ersten Oberfläche der Platte angeordnet sind, und vertikale Durchgangslöcher in einer
Fluidverbindung mit den horizontal ausgebildeten Kanälen, die sich zu einer zweiten
Oberfläche der Platte erstrecken, umfassen, wobei die Durchgänge für jeden Satz derart
ausgewählt werden, dass sie die Bildung von Extrusionsfasern durch die ersten und
zweiten Sätze von Spinndüsenmündungen mit ausgewählten Deniers erleichtern und die
Dosier-/Verteilungsplatte in der Hinsicht als eine Dosierfunktion wirkt, dass jeder
Durchgang, der einer jeweiligen Spinndüsenmündung entspricht, selektiv dimensioniert
wird, um den Druckabfall des Polymers, das durch den Durchgang fließt, und somit die
Zuführung von Polymer mit einem gewünschten Durchsatz an die jeweilige Spinndüsenmündung
zu steuern.
2. Spinnpaketanordnung nach Anspruch 1, wobei die Kanäle ein Verhältnis einer Kanalbreite
zu einer Kanaltiefe von etwa 1,5:1 bis etwa 15:1 haben.
3. Spinnpaketanordnung nach einem der Ansprüche 1 bis 2, wobei die Dosier-/Verteilungsplatte
unter Verwendung eines Ätzverfahrens hergestellt wird, um die Durchgänge der Platte
auszubilden.
4. Spinnpaketanordnung nach einem der Ansprüche 1 bis 3, die ferner mehrere Dosier-/Verteilungsplatten
aufweist, die aufgebaut sind, um geschmolzenes Polymer, das durch die Spinnpaketanordnung
fließt, an die Spinndüse zuzuführen.
5. Spinnpaketanordnung nach einem der Ansprüche 1 bis 4, wobei die Geometrien der Spinndüsenmündungen
rund und mehrlappig umfassen.
6. Spinnpaketanordnung nach einem der Ansprüche 1 bis 5, wobei die Spinnpaketanordnung
aufgebaut ist, um verschiedene Dosier-/Verteilungsplatten aufzunehmen, die verschiedene
Sätze von Durchgängen mit verschiedenen Durchgangsabmessungen umfassen.
7. Spinnpaketanordnung nach einem der Ansprüche 1 bis 6, wobei wenigstens eine Spinndüsenmündung
eine Geometrie hat, die aufgebaut ist, um eine Hohlfaser auszubilden.
8. Spinnpaketanordnung nach Anspruch 5, wobei die Geometrien der Spinndüsenmündungen
dreilappig umfassen.
9. Spinnpaketanordnung nach Anspruch 5, wobei wenigstens einige der runden Spinndüsenmündungen
in Bezug auf alle mehrlappigen Spinndüsenmündungen näher an Umfangsabschnitten der
Spinndüse angeordnet sind.
10. Spinnpaketanordnung nach Anspruch 5, wobei innerhalb eines ausgewählten Abschnitts,
der an jedem Längsendabschnitt der Spinndüse eingerichtet ist, nur runde Spinndüsenmündungen
angeordnet sind.
11. Spinnpaketanordnung nach Anspruch 5, wobei innerhalb eines mittleren Abschnitts der
Spinndüse nur runde Spinndüsenmündungen angeordnet sind.
12. Spinnpaketanordnung nach Anspruch 5, wobei wenigstens eine Gruppe der mehrlappigen
Spinndüsenmündungen entlang einer Auslassoberfläche der Spinndüse derart ausgebildet
ist, dass ein Lappen einer mehrlappigen Faser, die von jeder mehrlappigen Spinndüsenmündung
der wenigstens einen Gruppe extrudiert wird, derart ausgerichtet wird, dass er in
Richtung einer Abschreckmediumquelle gewandt ist, welche ein Abschreckmedium in Richtung
von Fasern leitet, die von der Spinndüse extrudiert werden.
13. Spinnpaketanordnung nach Anspruch 5, wobei die Spinndüse eine erste Gruppe von mehrlappigen
Spinndüsenmündungen und eine zweite Gruppe von mehrlappigen Spinndüsenmündungen, welche
die gleiche Geometrie wie die erste Gruppe von mehrlappigen Spinndüsenmündungen hat,
umfasst, wobei die mehrlappigen Mündungen der ersten Gruppe in einem ausgewählten
Drehwinkel in Bezug auf die mehrlappigen Spinndüsenmündungen der zweiten Gruppe entlang
einer Auslassoberfläche der Spinndüse ausgerichtet sind.
14. Spinnpaketanordnung nach Anspruch 13, wobei die mehrlappigen Spinndüsenmündungen der
ersten Gruppe in Bezug auf die mehrlappigen Spinndüsenmündungen der zweiten Gruppe
in einer 180°-Drehung ausgerichtet sind.
15. Spinnpaketanordnung nach einem der Ansprüche 1 bis 14, wobei wenigstens 50% der Spinndüsenmündungen
eine mehrlappige Geometrie haben.
16. Spinnpaketanordnung nach einem der Ansprüche 1 bis 14, wobei wenigstens 75% der Spinndüsenmündungen
eine mehrlappige Geometrie haben.
17. Spinnpaketanordnung nach einem der Ansprüche 1 bis 14, wobei wenigstens 80% der Spinndüsenmündungen
eine mehrlappige Geometrie haben.
18. Verfahren zur Ausbildung eines Filamentmischprodukts, das Polymerfasern mit verschiedenen
Querschnittsgeometrien enthält, wobei das Verfahren aufweist:
Bereitstellen einer Spinnpaketanordnung nach einem der Ansprüche 1 bis 17.
19. Verfahren nach Anspruch 18, wobei die Geometrien der Spinndüsenmündungen rund und
mehrlappig umfassen.
20. Verfahren nach Anspruch 19, wobei wenigstens eine Gruppe der mehrlappigen Spinndüsenmündungen
in der Spinndüse derart ausgebildet ist, dass ein Lappen einer mehrlappigen Faser,
die von jeder mehrlappigen Spinndüsenmündung der wenigstens einen Gruppe extrudiert
wird, derart ausgerichtet wird, dass er in Richtung einer Abschreckmediumquelle gewandt
ist, welche ein Abschreckmedium in Richtung von Fasern leitet, die von der Spinndüse
extrudiert werden.
21. Verfahren nach Anspruch 18, das ferner aufweist:
Bereitstellen der Durchgänge des ersten Satzes der Dosier-/Verteilungsplatte mit ausgewählten
Abmessungen, um die Deniers von Fasern zu steuern, die von dem ersten Satz von Spinndüsenmündungen
extrudiert werden; und
Bereitstellen der Durchgänge des zweiten Satzes der Dosier-/Verteilungsplatte mit
ausgewählten Abmessungen, um die Deniers von Fasern zu steuern, die von dem zweiten
Satz von Spinndüsenmündungen extrudiert werden.
22. Verfahren nach einem der Ansprüche 18 bis 21, das ferner aufweist:
Verändern wenigstens eines Betriebsparameters, der ausgewählt wird aus: Polymerdurchsatz
durch die Spinnpaketanordnung; Faserquerschnittsgeometrie von Fasern, die von der
Spinndüse ausgebildet werden, die Anordnung von Spinndüsenmündungen entlang der Spinndüse,
eine Temperatur von Polymermaterial, das durch die Spinnpaketanordnung fließt, das
Denier von Fasern, die von wenigstens einem der ersten und zweiten Sätze von Spinndüsenmündungen
ausgebildet werden, die Anzahl von Spinndüsenmündungen in wenigstens einem der ersten
und zweiten Sätze von Spinndüsenmündungen und das Polymermaterial von Fasern, die
von der Spinndüse extrudiert werden; und
Austauschen der Dosier-/Verteilungsplatte in der Spinnpaketanordnung durch eine andere
Dosier-/Verteilungsplatte, die ausgewählte Durchgangsabmessungen umfasst, um die selektive
Steuerung der Deniers von Fasern, die von der Spinndüse extrudiert werden, nach der
Veränderung des wenigstens einen Betriebsparameters zu erleichtern.
23. Verfahren nach einem der Ansprüche 18 bis 22, wobei Fasern, die von der Spinndüse
ausgebildet werden, wenigstens eines der folgenden umfassen: Fasern mit verschiedenen
Querschnittsgeometrien, aber mit der gleichen oder mehreren Polymerkomponenten und
Fasern mit unterschiedlichen Querschnittsgeometrien und unterschiedlichen Polymerkomponenten.
24. Verfahren nach einem der Ansprüche 18 bis 23, wobei wenigstens einige der von der
Spinndüse ausgebildeten Fasern Mehrpolymerkomponenten umfassen.
25. Spinnlegungssystem, das aufweist:
eine Spinnpaketanordnung nach einem der Ansprüche 1 bis 17; und
eine Abschreckquelle, die ausgerichtet und aufgebaut ist, um wenigstens ein Abschreckquellmedium
in Richtung von Fasern zu leiten, die von der Spinndüse extrudiert werden.
26. System nach Anspruch 25, wobei wenigstens eine Gruppe der mehrlappigen Spinndüsenmündungen
entlang einer Auslassoberfläche der Spinndüse derart ausgebildet ist, dass ein Lappen
einer mehrlappigen Faser, die von jeder mehrlappigen Spinndüsenmündung der wenigstens
einen Gruppe extrudiert wird, derart ausgerichtet wird, dass er in Richtung einer
Abschreckmediumquelle gewandt ist, welche ein Abschreckmedium in Richtung von Fasern
leitet, die von der Spinndüse extrudiert werden.
27. System nach Anspruch 25 oder 26, das ferner aufweist:
mehrere Dosierpumpen, um geschmolzenes Polymermaterial unabhängig an die Spinnpaketanordnung
zu dosieren.
28. System nach Anspruch 27, wobei eine erste Dosierpumpe ein geschmolzenes Polymermaterial
zu einem ersten Satz von Durchgängen der Dosier-/Verteilungsplatte dosiert und eine
zweite Dosierpumpe geschmolzenes Polymermaterial zu einem zweiten Satz von Durchgängen
der Dosier-/Verteilungsplatte dosiert.
1. Ensemble filière comprenant :
une filière comprenant une première série d'orifices de filière et une seconde série
d'orifices de filière, les orifices de filière de la première série ayant des géométries
différentes de celles des orifices de filière de la seconde série ; et
une plaque de dosage/distribution conçue pour fournir un polymère fondu, qui s'écoule
à travers l'ensemble filière, à la filière, la plaque de dosage/distribution comprenant
:
une première série de passages conçus pour fournir un polymère fondu, qui s'écoule
à travers l'ensemble filière, au premier ensemble d'orifices de filière ; et
une seconde série de passages conçus pour fournir un polymère fondu, qui s'écoule
à travers l'ensemble filière, au second ensemble d'orifices de filière ;
les passages de la plaque contenant des conduits, formés à l'horizontale, qui sont
disposés le long d'une première surface de la plaque, et des trous traversants verticaux
qui sont en communication de fluide avec les conduits formés à l'horizontale et qui
s'étendent jusqu'à une seconde surface de la plaque, les passages pour chaque série
étant sélectionnés pour faciliter la formation de fibres extrudées, à travers les
première et seconde séries d'orifices de filière présentant des deniers sélectionnés,
et la plaque de dosage/distribution servant à une fonction de dosage dans la mesure
où chaque passage qui correspond à un orifice de filière respectif est dimensionné
sélectivement de manière à commander la chute de pression de l'écoulement de polymère
à travers le passage, et ainsi la fourniture de polymère à l'orifice de filière respectif
à un débit voulu.
2. Ensemble filière de la revendication 1, dans lequel les conduits présentent un rapport
largeur de conduit sur profondeur de conduit d'environ 1,5:1 à environ 15:1.
3. Ensemble filière de l'une quelconque des revendications 1 à 2, dans lequel la plaque
est réalisée à l'aide d'un procédé de gravure pour former les passages de la plaque.
4. Ensemble filière de l'une quelconque des revendications 1 à 3, comprenant également
un ensemble de plaques de dosage/distribution conçues pour fournir un polymère fondu,
qui s'écoule à travers l'ensemble filière, à la filière.
5. Ensemble filière de l'une quelconque des revendications 1 à 4, dans lequel les géométries
des orifices de filière comprennent des géométries rondes et multilobées.
6. Ensemble filière de l'une quelconque des revendications 1 à 5, l'ensemble filière
étant conçu pour recevoir différentes plaques de dosage/distribution comprenant différentes
séries de passages avec des dimensions de passages différentes.
7. Ensemble filière de l'une quelconque des revendications 1 à 6, dans lequel au moins
un orifice de filière a une géométrie qui est conçue pour former une fibre creuse.
8. Ensemble filière de la revendication 5, dans lequel les géométries des orifices de
filière comprennent une géométrie trilobée.
9. Ensemble filière de la revendication 5, dans lequel certains au moins des orifices
de filière ronds se trouvent plus près de parties périphériques de la filière, par
rapport à tous les orifices de filière multilobés.
10. Ensemble filière de la revendication 5, dans lequel seuls les orifices de filière
ronds se trouvent à l'intérieur d'une section sélectionnée disposée sur chaque partie
d'extrémité longitudinale de la filière.
11. Ensemble filière de la revendication 5, dans lequel seuls les orifices de filière
ronds se trouvent à l'intérieur d'une partie centrale de la filière.
12. Ensemble filière de la revendication 5, dans lequel au moins un groupe d'orifices
de filière multilobés sont formés le long d'une surface de sortie de la filière de
telle sorte qu'un lobe d'une fibre multilobée extrudée à partir de chaque orifice
de filière multilobé du ou des groupes est aligné pour être dirigé dans une direction
d'une source d'agent de trempe qui dirige un agent de trempe vers les fibres extrudées
à partir de la filière.
13. Ensemble filière de la revendication 5, dans lequel la filière comprend un premier
groupe d'orifices de filière multilobés, et un second groupe d'orifices de filière
multilobés qui ont la même forme géométrique que le premier groupe d'orifices de filière
multilobés, les orifices multilobés du premier groupe sont alignés le long d'une surface
de sortie de la filière suivant un angle de rotation sélectionné, par rapport aux
orifices de filière multilobés du second groupe.
14. Ensemble filière de la revendication 13, dans lequel les orifices de filière multilobés
du premier groupe sont alignés suivant un angle de rotation de 180° par rapport aux
orifices de filière multilobés du second groupe.
15. Ensemble filière de l'une quelconque des revendications 1 à 14, dans lequel au moins
50 % des orifices de filière ont une géométrie multilobée.
16. Ensemble filière de l'une quelconque des revendications 1 à 14, dans lequel au moins
75 % des orifices de filière ont une géométrie multilobée.
17. Ensemble filière de l'une quelconque des revendications 1 à 14, dans lequel au moins
80 % des orifices de filière ont une géométrie multilobée.
18. Procédé pour former un produit en filaments mixtes contenant des fibres de polymère
de géométries de section transversale différentes, le procédé comprenant la mesure
consistant :
à prévoir un ensemble filière de l'une quelconque des revendications 1 à 17.
19. Procédé selon la revendication 18, selon lequel les géométries des orifices de filière
comprennent des géométries rondes et multilobées.
20. Procédé selon la revendication 19, selon lequel au moins un groupe d'orifices de filière
multilobés sont formés dans la filière de telle sorte qu'un lobe d'une fibre multilobée
extrudée à partir de chaque orifice de filière multilobé du ou des groupes est aligné
pour être dirigé dans une direction d'une source d'agent de trempe qui dirige un agent
de trempe vers les fibres extrudées à partir de la filière.
21. Procédé selon la revendication 18, comprenant également les mesures qui consistent
à doter les passages de la première série de la plaque de dosage/distribution de dimensions
sélectionnées, pour commander les deniers de fibres extrudées à partir de la première
série d'orifices de filière ; et
à doter les passages de la seconde série de la plaque de dosage/distribution de dimensions
sélectionnées, pour commander les deniers de fibres extrudées à partir de la seconde
série d'orifices de filière.
22. Procédé selon l'une quelconque des revendications 18 à 21, comprenant également les
mesures qui consistent :
à modifier au moins un paramètre de fonctionnement sélectionné parmi : le débit de
polymère à travers l'ensemble filière, la géométrie de section transversale des fibres
formées à partir de la filière, la disposition des orifices de filière le long de
la filière, une température du matériau polymère qui s'écoule à travers l'ensemble
filière, le denier des fibres formées à partir de l'une au moins des première et seconde
séries d'orifices de filière, le nombre d'orifices de filière dans l'une au moins
des première et seconde séries d'orifices de filière, et le matériau polymère des
fibres extrudées à partir de la filière ; et
à remplacer la plaque de dosage/distribution dans l'ensemble filière par une plaque
de dosage/distribution différente présentant des dimensions de passage sélectionnées,
afin de faciliter la commande sélective des deniers de fibres extrudées à partir de
la filière, après la modification du ou des paramètres de fonctionnement.
23. Procédé selon l'une quelconque des revendications 18 à 22, selon lequel les fibres
formées à partir de la filière comprennent l'un au moins des éléments suivants : des
fibres ayant des géométries de section transversale différentes, mais avec le ou les
mêmes composants polymères, et des fibres ayant des géométries de section transversale
différentes et des composants polymères différents.
24. Procédé selon l'une quelconque des revendications 18 à 23, selon lequel certaines
au moins des fibres formées à partir de la filière contiennent des composants multipolymères.
25. Système filé-lié, comprenant :
un ensemble filière tel qu'il est revendiqué dans l'une quelconque des revendications
1 à 17 ; et
une source de trempe alignée et conçue pour diriger au moins une source d'agent de
trempe vers des fibres extrudées à partir de la filière.
26. Système de la revendication 25, dans lequel au moins un groupe d'orifices de filière
multilobés sont formés le long d'une surface de sortie de la filière de telle sorte
qu'un lobe d'une fibre multilobée extrudée à partir de chaque orifice de filière multilobé
du ou des groupes est aligné pour être dirigé dans une direction d'une source d'agent
de trempe qui dirige un agent de trempe vers les fibres extrudées à partir de la filière.
27. Système de la revendication 25 ou 26, comprenant également :
un ensemble de pompes de dosage pour doser indépendamment un matériau polymère fondu
vers l'ensemble filière.
28. Système de la revendication 27, dans lequel une première pompe doseuse mesure un matériau
polymère fondu vers la première série de passages de la plaque de dosage/distribution,
et une seconde pompe doseuse mesure le matériau polymère fondu vers la seconde série
de passages de la plaque de dosage/distribution.