U.S. patent application number 10/898855 was filed with the patent office on 2005-01-13 for hetero-composite yarn, fabrics thereof and methods of making.
This patent application is currently assigned to INVISTA Sarl. Invention is credited to Figuly, Garret D., Goldfinger, Marc B., Mehta, Rakesh H., Samuelson, H. Vaughn, Soroka, Anthony J., Weeks, Gregory P..
Application Number | 20050008855 10/898855 |
Document ID | / |
Family ID | 23268660 |
Filed Date | 2005-01-13 |
United States Patent
Application |
20050008855 |
Kind Code |
A1 |
Figuly, Garret D. ; et
al. |
January 13, 2005 |
Hetero-composite yarn, fabrics thereof and methods of making
Abstract
A hetero-composite yarn useful in making garments comprises a
combined biconstituent yarn and a companion yarn, wherein the
biconstituent yarn comprises an axial core comprising a
thermoplastic elastomeric polymer, and a plurality of wings
attached to the core and comprising a thermoplastic,
non-elastomeric polymer.
Inventors: |
Figuly, Garret D.;
(Wilmington, DE) ; Goldfinger, Marc B.;
(Philadelphia, PA) ; Mehta, Rakesh H.; (Hockessin,
DE) ; Samuelson, H. Vaughn; (Chadds Ford, PA)
; Soroka, Anthony J.; (Nashville, TN) ; Weeks,
Gregory P.; (Hockessin, DE) |
Correspondence
Address: |
INVISTA NORTH AMERICA S.A.R.L.
4417 LANCASTER PIKE
CRP 722/1032
WILMINGTON
DE
19805
US
|
Assignee: |
INVISTA Sarl
Wilmington
DE
|
Family ID: |
23268660 |
Appl. No.: |
10/898855 |
Filed: |
July 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10898855 |
Jul 26, 2004 |
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10256346 |
Sep 27, 2002 |
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6783853 |
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60325619 |
Sep 28, 2001 |
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Current U.S.
Class: |
428/364 |
Current CPC
Class: |
Y10T 428/2913 20150115;
D01F 8/16 20130101; D01D 5/30 20130101; Y10T 428/2931 20150115;
D01F 8/04 20130101; D01F 8/14 20130101; D01F 8/06 20130101; D01F
8/12 20130101; D02G 1/18 20130101; Y10T 428/2973 20150115; Y10T
428/2924 20150115; Y10T 428/2929 20150115; D01D 5/253 20130101 |
Class at
Publication: |
428/364 |
International
Class: |
D02G 003/00 |
Claims
1-13. (Canceled).
14. A process of making a hetero-composite yarn comprising passing
a melt comprising at least one thermoplastic non-elastomeric
polymer and a melt comprising a thermoplastic elastomeric polymer
through a spinneret to form a plurality of stretchable synthetic
polymeric filaments comprising an axial core comprising the
elastomeric polymer and a plurality of wings comprising the
non-elastomeric polymer attached to the core, quenching the
filaments after they exit the capillary of the spinneret to cool
the filaments, and collecting the filaments to form a biconstituent
yarn, and commingling the biconstituent yarn with a companion
yarn.
15. A process as claimed in claim 14, wherein the comingling
comprises air jet texturing the bioconstituent yarn and the
companion yarn together.
16. A process as claimed in claim 14, wherein the comingling
comprises air entangling the biconstituent yarn and the companion
yarn together.
17. A process as claimed in claim 14, wherein one or both of the
biconstituent and second yarn before combining, are in the form of
a staple yarn.
18. The process of claim 14, comprising an additional step, after
quenching, of heat-relaxing the fiber so that it exhibits at least
about 20% after-boil-off stretch.
19. The process as claimed in claim 18, wherein the heat-relaxing
is carried out with a heating medium of dry air, hot water or
superatmospheric pressure steam at a temperature in the range of
about 80.degree. C. to about 120.degree. C. when the heating medium
is said dry air, about 75.degree. C. to about 100.degree. C. when
the heating medium is said hot water, and about 101.degree. C. to
about 115.degree. C. when the heating medium is said
superatmospheric pressure steam.
20. A process of making a synthetic polymer yarn comprising
commingling one or more biconstituent filaments with at least one
other filament, and forming a synthetic polymer yarn from the
commingled filaments, wherein said biconstituent filament comprises
an axial core comprising a thermoplastic elastomeric polymer, and a
plurality of wings comprising a thermoplastic, non-elastomeric
polymer attached to the core.
Description
CROSS REFERENCE(S) TO RELATED APPLICATION(S)
[0001] This application claims priority of U.S. Provisional Patent
Application 60/325,619 filed Sep. 28, 2001.
FIELD OF THE INVENTION
[0002] The invention relates to hetero-composite, preferably
self-bulking, textile yarn with high stretch recovery, produced
from a high-shrinkage, latent stretch, melt spun biconstituent
fiber and one or more lower shrinkage fibers.
BACKGROUND OF THE INVENTION
[0003] Yarns which exhibit good bulk and stretch and recovery are
made by a variety of processes, including false twist texturing of
non-elastic or hard yarns, bicomponent yarns, wrap covering a hard
yarn onto an elastomeric yarn, air covering or entangling a hard
yarn with an elastomeric yarn, and core spinning of staple yarn
covers on an elastomeric yarn. See, for example, U.S. Pat. No.
4,861,660 to Ishii. Fabrics of enhanced bulk, stretch and recovery
properties are made by incorporating one or more of these yarn
types into the fabric and/or by using an elastomeric, such as
spandex, yarn, which is fed separately into the fabric production
process.
[0004] Fabrics with good stretch and recovery properties generally
require separate processes to prepare the hard yarns or at least a
separate yarn feed for incorporating a stretchable, elastomeric
yarn. Often the stretchable yarns will require special tensioning
devices. For example, the elastomer often requires a covering step
which can be expensive, slow, and requires careful control of
elastic tension or draft. Once covered, e.g., by wrapping or air
entangling, the yarn is still elastomeric in nature. Variability in
tensioning of the elastomer component can lead to quality defects.
Also, if the elastomer is not pre-covered other problems may occur,
such as dye uniformity problems because elastomers dye differently
than companion yarns, and/or early failure of bare elastomer which
has lower tenacity than the companion yarns.
[0005] Ishii describes asymmetric biconstituent filament yarns that
can be knitted and woven with nylon yarns in Examples 15 and 16
respectively. These examples teach knitting and weaving the
biconstituent filament yarn and the nylon yarn separately in a
fabric. In light of the extremely high shrinkage of biconstituent
filament yarns, which are high stretch yarns, Ishii recognizes that
relaxation of the biconstituent filament yarns is necessary to
handle the yarn prior to making the fabric.
[0006] High stretch yarns require careful control of yarn tension
to achieve uniform properties, and these properties can fluctuate
due to denier variations, finish level, etc. Therefore, Ishii
prefers tensioning the yarn to insure a uniform feed in length and
elastic properties in the fabric structure. However, tensioning
also requires capital investment and maintenance.
[0007] Moreover, it is often desirable to use yarns which have not
been relaxed during spinning at all. This retains the maximum
shrinkage, both recoverable and non-recoverable, in the
biconstituent filaments, providing for optimum stretch and bulking
potential in the composite yarn.
[0008] Thus, there is a continuing need to provide yarns and
articles therefrom, that exhibit desired stretch and recovery
properties, and in particular, yarns which have not been fully
relaxed prior to making fabrics and articles therefrom. It is also
desirable to design a process for making yarns with desired stretch
and recovery properties which does not require tensioning.
SUMMARY OF THE INVENTION
[0009] While 100% biconstituent yarn can be useful, the economics
and the stretch recovery properties of the biconstituents will
often show best in composite yarns and fabrics. In many fabrics a
content of 10-50% is adequate to provide useful stretch recovery
properties, and other tactile and aesthetic benefits. The yarn of
the present invention fulfills the continuing need to provide yarns
and articles therefrom that exhibit desired stretch and recovery
properties, and also overcomes the problems associated with
relaxed, high stretch biconstituent filament yarns of the prior
art. The present invention achieves this by providing a hetero-yarn
where the biconstituent filament yarns are pre-combined with a
companion yarn in a unitary yarn structure. Such hetero-yarn does
not require relaxation in order to handle the yarn prior to making
a fabric. Rather, the "elastic potential" of the hetero yarns of
the present invention is integrated at the biconstituent processing
stage. These hetero-yarns can be treated as hard yarns in fabric
manufacture. The elastic potential is activated in the finishing of
the fabric. In addition, s/z twist control is not required.
[0010] The hetero yarn of the present invention overcomes many of
the drawbacks of Ishii in particular. For instance, the hetero-yarn
of the present invention avoids heat cross-linking or heat relaxing
the yarn prior to use. This is an advantage over Ishii, which
preferred a two-step thermal cross-linking process. The hetero yarn
of the present invention also avoids the need for tensioning, as
preferred in Ishii, by feeding the biconstituent yarn in the hard
yarn state. As noted above, tensioning requires capital investment
and maintenance. Feeding the biconstituent in the hard yarn state
is therefore more economical and reliable than the process
described in Ishii, providing yarn properties are consistent.
[0011] In many cases high shrinkage can be accommodated in
fabrication or used to an advantage, and the present invention
makes use of this. Applicants have found that greige fabric and
garment constructions from the yarn of the present invention can be
adjusted to allow for the extra shrinkage. Further, high shrinkage
can be used to an advantage in many fabric constructions, for
instance to increase fabric bulk in hetero yarn structures, or to
reduce or control knit fabric porosity in bottomweight knits. Also,
yarns slightly relaxed on the face plate during spinning (5%-20%)
substantially reduce non-recoverable shrinkage in finishing and
enhance yarn toughness for knitting, while substantially retaining
hard yarn package delivery characteristics.
[0012] Moreover, the co-mingling and co-texturing of yarns is more
productive where two yarns to be co-mingled and co-textured have
similar properties. In the present invention, the biconstituent
yarn in the drawn pre-relaxed state has properties similar to the
hard companion yarns, and very different from standard elastomeric
fibers. Thus, the biconstituent yarn of the present invention can
be air textured or air mingled efficiently with other hard
companion yarns.
[0013] With the present invention, premature shrinkage can be
controlled by proper package formation and package hardness.
Applicants have found that it is possible to wind large packages of
monofilament biconstituent in the unactivated state, and to store
them for several months without significant loss of properties or
change in package hardness.
[0014] In addition, the high shrinkage associated with
biconstituent filaments requires that, on shrinking, the lower
shrink companion yarn must bulk. The present invention envisions
that either straight or textured companion yarns may be combined
with biconstituent yarns. Straight companion yarns will tend to
form loops which can be advantageous in some fabrics (say formation
a terry surface fabric) or a negative in other cases (may increase
fabric picking). However, companion yarns which have been cubicly
crimped, or textured, have natural bends for storage of the added
bulk when the biconstituent filaments shrink; biconstituent yarns
with textured companion yarns have smoother or cotton-like surfaces
which are often advantageous in many apparel applications.
[0015] The above-mentioned advantages are obtained by the present
invention, which provides a hetero-composite yarn comprising a
combined biconstituent yarn and a companion yarn, wherein the
biconstituent yarn comprises at least one biconstituent filament
including an axial core comprising a thermoplastic, elastomeric
polymer and a plurality of wings attached to the core and
comprising a thermoplastic, non-elastomeric polymer.
[0016] The above-mentioned advantages are also obtained by the
present invention which provides a process for making a
hetero-composite yarn, comprising spinning a biconstituent yarn and
a companion yarn together, wherein the biconstituent yarn comprises
at least one biconstituent filament including an axial core
comprising a thermoplastic, elastomeric polymer and a plurality of
wings attached to the core and comprising a thermoplastic,
non-elastomeric polymer.
BRIEF DESCRIPTION OF THE FIGURES
[0017] FIG. 1 is a representation of a
hetero-composite-composite-yarn of the present invention.
[0018] FIG. 2 is a schematic cross-section of a fiber of the
invention.
[0019] FIG. 3 is a schematic cross-section of a fiber of the
invention with the wing polymer protruding into the core.
[0020] FIG. 4 is a schematic cross-section of a fiber of the
invention with the core polymer protruding into the wings.
[0021] FIG. 5 is a process schematic apparatus useful for making
fibers of this invention.
[0022] FIG. 6 is a representation of a stacked plate spinneret
assembly, in side elevation, that can be used to make the fiber of
the invention.
[0023] FIG. 6A is a representation of orifice Plate A in plan view
at 90.degree. to the stacked plate spinneret assembly shown in FIG.
6 and taken across lines 6A-6A of FIG. 6.
[0024] FIG. 6B is a representation of an orificie Plate B in plan
view at 90.degree. to the stacked plate spinneret assembly shown in
FIG. 6 and taken across lines 6B-6B of FIG. 6.
[0025] FIG. 6C is a representation of orifice Plate C in plan view
at 90.degree. to the stacked plate spinneret assembly shown in FIG.
8 and taken across lines 6C-6C of FIG. 6.
[0026] FIG. 7A shows in cross-sectional cut-away a representation a
prior art spinneret plate.
[0027] FIGS. 7B and 7C show in cross-sectional cut-away a
representation two spinneret plates of the invention.
[0028] FIG. 8 is a representation of a stacked plate spinneret
assembly, in side elevation, that can be used to make alternative
embodiment fiber of the invention.
[0029] FIGS. 8A, 8B and 8C show respectively, an alternative
embodiment of a spinneret plate, distribution plate, and metering
plate, in plan view at 90.degree. to the stacked plate spinneret
assembly of FIG. 8, each of which can be used in a spinneret pack
assembly of the invention to make an alternative embodiment fiber
of the invention.
[0030] FIGS. 9A, 9B, and 9C show respectively, another alternative
embodiment of a spinneret plate, distribution plate, and metering
plate, in plan view at 90.degree. to the stacked plate spinneret
assembly of FIG. 8, each of which can be used in a spinneret pack
assembly of the invention to make an alternative embodiment fiber
of the invention.
[0031] FIG. 10 is a schematic of a process for spinning a
biconstituent filament and a process for spinning a companion
yarn.
[0032] FIG. 11 is a schematic of alternative process schemes for
combining a biconstituent filament with a companion yarn.
[0033] FIG. 12 is a schematic of an alternative process for
combining a biconstituent filament with a companion yarn.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0034] In accordance with the present invention, there is provided
a hetero-composite yarn comprising a combined biconstituent yarn
and companion yarn. FIG. 1 is a representation of a micrograph
taken of the hetero-composite combination yarn of invention in side
section. The biconstituent yarn is shown at 10 in FIG. 1, and the
companion yarn is shown at 20 in FIG. 2. FIGS. 2-4 are
cross-sectional profiles of a biconstituent fiber. The
biconstituent yarn comprises at least one filament, shown generally
at 10 in FIGS. 1-4, with an axial core, shown at 12 and a plurality
of wings, shown at 14 in FIGS. 2-4, attached to the core. The axial
core comprises a thermoplastic elastomeric polymer, the wings
comprise at least one thermoplastic, non-elastomeric polymer
attached to the core. Preferably, the thermoplastic,
non-elastomeric polymer is permanently drawable.
[0035] As used herein, the term "fiber" is interchangeable with the
term "filament". The term "yarn" includes yarns of a single
filament. The term "multifilament yarn" generally relates to yarns
of two or more filaments. The term "thermoplastic" refers to a
polymer which can be repeatedly melt-processed (for example
melt-spun). By `elastomeric polymer` is meant a polymer which in
monocomponent fiber form, free of diluents, has a break elongation
in excess of 100% and which when stretched to twice its length,
held for one minute, and then released, retracts to less than 1.5
times its original length within one minute of being released. The
elastomeric polymers in the fiber of the invention can have a flex
modulus of less than about 14,000 pounds per square inch (96,500
kPascals), more typically less than about 8500 pounds per square
inch (58,600 kpascals) when present in a monocomponent fiber spun
at 23.degree. C. and under conditions substantially as described
herein. As used herein, "non-elastomeric polymer" means any polymer
which is not an elastomeric polymer. Such polymers can also be
termed "low elasticity", "hard: and "high modulus". By "permanently
drawable" is meant that the polymer has a yield point, and if the
polymer is stretched beyond such point it will not return to its
original length.
[0036] The fibers of the invention are termed "biconstituent"
fibers when they are comprised of at least two polymers adhered to
each other along the length of the fiber, each polymer being in a
different generic class, e.g., polyamide, polyester or polyolefin.
If the elastic characteristics of the polymers are sufficiently
different, polymers of the same generic class can be used, and the
resulting fiber is a "bicomponent" fiber. Such bicomponent fibers
are also within the scope of the invention.
[0037] According to the invention, at least one of the wing polymer
and the core polymer protrudes into the other polymer. FIG. 3 shows
the wing polymer protruding into the core polymer, and FIG. 4 shows
the core polymer protruding into the wing polymer. The penetration
of core and wing polymers can be accomplished by any method
effective for reducing splitting of the fiber. For example, in one
embodiment, the penetrating polymer (for example the wing polymer)
can protrude into the penetrated polymer (for example the core
polymer) like the roots of a tooth, so that a plurality of
protrusions are formed. In another embodiment, the penetrating
polymer (for example the core polymer) can protrude so far into the
penetrated polymer (for example the wing polymer), that the
penetrating polymer is like a spline. A spline has substantively
uniform diameter. In yet another embodiment, at least one polymer
can have at least one protruding portion, of a single wing into
core or core into wing, which includes a remote enlarged end
section and a reduced neck section joining the end section to the
remainder of the at least one polymer to form at least one
necked-down portion therein. Wings and core attached to each other
by such an enlarged end section and reduced neck section are
referred to as `mechanically locked`. For ease of manufacture and
more effective adhesion between wings and core, the last-mentioned
embodiment having a reduced neck section is often preferred. Other
protrusion methods can be envisioned by those skilled in the art.
For example, the core can surround a portion of the side of one or
more wings, such that a wing penetrates the core.
[0038] The fiber of the invention includes an axial core with an
outer radius and an inner radius (for example "R.sub.1" and
"R.sub.2", respectively, in FIGS. 3 and 4). The outer radius is
that of a circle circumscribing the outermost portions of the core,
and the inner radius is that of a circle inscribing the innermost
portions of the wings. In the fibers of the invention,
R.sub.1/R.sub.2 is generally greater than about 1.2. It is
preferred that R.sub.1/R.sub.2 be in the range of about 1.3 to
about 2.0. Resistance to delamination can decline at lower ratios,
and at higher ratios the high levels of elastomeric polymer in the
wings (or of non-elastomeric polymer in the core) can decrease the
stretch and recovery of the fiber. When the core forms a spline
within the wing, R.sub.1/R.sub.2 approaches 2. In contrast, in a
fiber where one of the wing or core polymer does not protrude into
the other polymer, R.sub.1 approximates R.sub.2, so that neither
wings nor core penetrate the other. In cases in which among the
plurality of wings, the polymer in some wings penetrates the core
polymer while the polymer in other wings is penetrated by the core
polymer, R.sub.1 and R.sub.2 are determined only as pairs
corresponding to each wing, and each ratio R.sub.1/R.sub.2 and
R.sub.1'/R.sub.2' is generally greater than about 1.2, preferably
in the range of about 1.3 to 2.0. In another embodiment, some wings
can be penetrated by core polymer while adjacent wings are not
penetrated, and R.sub.1 and R.sub.2 are determined in relationship
to penetrated wings; similarly, R.sub.1 and R.sub.2 are determined
in relationship to penetrating wings when only some parts of the
core are penetrated by wing polymer. Any combination of core into
wing, wing into core, and no penetration can be used for the wings
so long as at least one wing penetrates core or is penetrated by
core.
[0039] The fiber of the present invention is twisted around its
longitudinal axis, without significant two- or three-dimensional
crimping characteristics. (In such higher-dimensional crimping, a
fiber's longitudinal axis itself assumes a zig-zag or helical
configuration; such fibers are not of the invention). The fiber of
the present invention may be characterized as having substantially
spiral twist and one dimensional spiral twist. "Substantially
spiral twist" includes both spiral twist that passes completely
around the elastomeric core and also spiral twist that passes only
partly around the core, since it has been observed that a fully
360.degree. spiral twist is not necessary to achieve the desirable
stretch properties in the fiber. The substantially spiral twist can
be either almost completely circumferential, or almost completely
noncircumferential. "One dimensional" spiral twist means that while
the wings of the fiber can be substantially spiral, the axis of the
fiber is substantially straight even at low tension, in contrast to
fibers having 2- or 3-dimensional crimp. However, fibers having
some waviness are within the scope of the invention.
[0040] The presence or absence of two- and three-dimensional crimp
can be gauged from the amount of stretch needed to substantially
straighten the fiber (by pulling out any non-linearities) and is a
measure of the radial symmetry of fibers having spiral twist. The
fiber of the invention can require less than about 10% stretch,
more typically less than about 7% stretch, for example about 4% to
about 6%, to substantially straighten the fiber.
[0041] The fiber of the present invention has a substantially
radially symmetric cross-section, as can be seen from FIGS. 1-4. By
"substantially radially symmetric cross-section" is meant a
cross-section in which the wings are located and are of dimensions
so that rotation of the fiber about its longitudinal axis by 360/n
degrees, in which "n" is an integer representing the "n-fold"
symmetry of the fibers, results in substantially the same
cross-section as before rotation. The cross-section is
substantially symmetrical in terms of size, polymer and angular
spacing around the core. This substantially radially symmetric
cross-section impartes an unexpected combination of high stretch
and high uniformity without significant levels of two- or
three-dimensional crimp. Such uniformity is advantageous in
high-speed processing of fibers, for example through guides and
knitting needles, and in making smooth, non-`picky` fabrics,
especially sheer fabrics like hosiery. Fibers which have a
substantially radially symmetric cross-section possess no
self-crimping potential, i.e., they have no significant two- or
three-dimensional crimping characteristics. See generally Textile
Research Journal, June 1967, p. 449.
[0042] For maximum cross-sectional radial symmetry, the core can
have a substantially circular or a regular polyhedral
cross-section, e.g., as seen in FIGS. 1-4. By "substantially
circular" it is meant that the ratio of the lengths of two axes
crossing each other at 90.degree. in the center of the fiber
cross-section is no greater than about 1.2:1. The use of a
substantially circular or regular polyhedron core, in contrast to
the cores of U.S. Pat. No. 4,861,660, can protect the elastomer
from contact with the rolls, guides, etc. as described later with
reference to the number of wings. The plurality of wings can be
arranged in any desired manner around the core, for example,
discontinuously as depicted in FIGS. 1 and 2, i.e., the wing
polymer does not form a continous mantel on the core, or with
adjacent wing(s) meeting at the core surface, e.g., as illustrated
in FIGS. 4 and 5 of U.S. Pat. No. 3,418,200. The wings can be of
the same or different sizes, provided a substantially radial
symmetry is preserved. Further, each wing can be of a different
polymer from the other wings, once again provided substantially
radial geometric and polymer composition symmetry is maintained.
However, for simplicity of manufacture and ease of attaining radial
symmetry, it is preferred that the wings be of approximately the
same dimensions, and be made of the same polymer or blend of
polymers. It is also preferred that the wings discontinuously
surround the core for ease of manufacture.
[0043] While the fiber cross-section is substantially symmetrical
in terms of size, polymer, and angular spacing around the core, it
is understood that small variations from perfect symmetry generally
occur in any spinning process due to such factors as non-uniform
quenching or imperfect polymer melt flow or imperfect spinning
orifices. It is to be understood that such variations are
permissible provided that they are not of a sufficient extent to
detract from the objects of the invention, such as providing fibers
of desired stretch and recovery via one-dimensional spiral twist,
while minimizing two- and three-dimensional crimping. That is, the
fiber is not intentionally made asymmetrical as in U.S. Pat. No.
4,861,660.
[0044] The wings protrude outward from the core to which they
adhere and form a plurality of spirals at least part way around the
core especially after effective heating. The pitch of such spirals
can increase when the fiber is stretched. The fiber of the
invention has a plurality of wings, preferably 3-8, more preferably
5 or 6. The number of wings used can depend on other features of
the fiber and the conditions under which it will be made and used.
For example, 5 or 6 wings can be used when a monofilament is being
made, especially at higher draw ratios and fiber tensions. In this
case the wing spacing can be frequent enough around the core that
the elastomer is protected from contact with rolls, guides, and the
like and therefore less subject to breaks, roll wraps and wear than
if fewer wings were used. The effect of higher draw ratios and
fiber tensions is to press the fiber harder against rolls and
guides, thus splaying out the wings and bringing the elastomeric
core into contact with the roll or guide; hence the preference for
more than two wings at high draw ratios and fiber tensions. In
monofilaments, five or six wings are often preferred for an optimum
combination of ease of manufacture and reduced core contact. When a
multifiber yarn is desired, as few as two or three wings can be
used because the likelihood of contact between the elastomeric core
and rolls or guides is reduced by the presence of the other
fibers.
[0045] While it is preferred that the wings discontinuously
surround the core for ease of manufacture, the core may include on
its outside surface a sheath of a non-elastomeric polymer between
points where the wings contact the core. The sheath thickness can
be in the range of about 0.5% to about 15% of the largest radius of
the fiber core. The sheath can help with adhesion of the wings to
the core by providing more contact points between the core and wing
polymers, a particularly useful feature if the polymers in the
biconstituent fiber do not adhere well to each other. The sheath
can also reduce abrasive contact between the core and rolls,
guides, and the like, especially when the fiber has a low number of
wings.
[0046] The core and/or wings of the multiwinged cross-section of
the present invention may be solid or include hollows or voids.
Typically, the core and wings are both solid. Moreover, the wings
may have any shape, such as ovals, T-, C-, or S-shapes. Examples of
useful wing shapes are found in U.S. Pat. No.4,385,886. T, C, or S
shapes can help protect the elastomer core from contact with guides
and rolls as described previously.
[0047] The weight ratio of total wing polymer to core polymer can
be varied to impart the desired mix of properties, e.g., desired
elasticity from the core and other properties such as low tackiness
from the wing polymer. For example, a weight ratio of about 10/90
to about 70/30, preferably about 30/70 to about 40/60 of wing to
core can be used. For high durability combined with high stretch in
uses in which the fiber need not be used with a companion yarn (for
example hosiery), a wing/core weight ratio of about 35/65 to about
50/50 is preferred. For best adhesion between the core and wings,
typically about 5 wt % to about 30 wt % of the total fiber weight
can be non-elastic polymer penetrating the core, or elastic core
polymer penetrating the wings.
[0048] As noted above, the core of the fiber of the invention can
be formed from any thermoplastic elastomeric polymer. Examples of
useful elastomers include thermoplastic polyurethanes,
thermoplastic polyester elastomers, thermoplastic polyolefins,
thermoplastic polyesteramide elastomers and thermoplastic
polyetheresteramide elastomers.
[0049] Useful thermoplastic polyurethane core elastomers include
those prepared from a polymeric glycol, a diisocyanate, and at
least one diol or diamine chain extender. Diol chain extenders are
preferred because the polyurethanes made therewith have lower
melting points than if a diamine chain extender were used.
Polymeric glycols useful in the preparation of the elastomeric
polyurethanes include polyether glycols, polyester glycols,
polycarbonate glycols and copolymers thereof. Examples of such
glycols include poly(ethyleneether)glycol,
poly(tetramethyleneether)glyco- l, poly(tetra
methylene-co-2-methyl-tetra methyleneether)glycol,
poly(ethylene-co-1,4-butylene adipate)glycol,
poly(ethylene-co-1,2-propyl- ene adipate) glycol,
poly(hexamethylene-co-2,2-dimethyl-1,3-propylene adipate),
poly(3-methyl-1,5-pentylene adipate)glycol,
poly(3-methyl-1,5-pentylene nonanoate)glycol,
poly(2,2-dimethyl-1,3-propy- lene dodecanoate)glycol,
poly(pentane-1,5-carbonate)glycol, and
poly(hexane-1,6-carbonate)glycol. Useful diisocyanates include
1-isocyanato-4-[(4-isocyanatophenyl )methyl]benzene,
1-isocyanato-2-[(4-isocyanato-phenyl)methyl]benzene, isophorone
diisocyanate, 1,6-hexanediisocyanate,
2,2-bis(4-isocyanatophenyl)propane,
1,4-bis(p-isocyanato,alpha,alpha-dimethylbenzyl)benzene,
1,1'-methylenebis(4-isocyanatocyclohexane), and 2,4-tolylene
diisocyanate. Useful diol chain extenders include ethylene glycol,
1,3 propane diol, 1,4-butanediol, 2,2-dimethyl-1,3-propylene diol,
diethylene glycol, and mixtures thereof. Preferred polymeric
glycols are poly(tetramethyleneether)glycol,
poly(tetramethylene-co-2-methyl-tetramet- hyleneether)glycol,
poly(ethylene-co-1,4-butylene adipate)glycol, and
poly(2,2-dimethyl-1,3-propylene dodecanoate)glycol.
1-Isocyanato-4-[(4-isocyanatophenyl)methyl]benzene is a preferred
diisocyanate. Preferred diol chain extenders are 1,3 propane diol
and 1,4-butanediol. Monofunctional chain terminators such as
1-butanol and the like can be added to control the molecular weight
of the polymer.
[0050] Useful thermoplastic polyester elastomers include the
polyetheresters made by the reaction of a polyether glycol with a
low-molecular weight diol, for example, a molecular weight of less
than about 250, and a dicarboxylic acid or diester thereof, for
example, terephthalic acid or dimethyl terephthalate. Useful
polyether glycols include poly(ethyleneether) glycol,
poly(tetramethyleneether)glycol,
poly(tetramethylene-co-2-methyltetramethyleneether)glycol [derived
from the copolymerization of tetrahydrofuran and
3-methyltetrahydrofuran] and
poly(ethylene-co-tetramethyleneether)glycol. Useful low-molecular
weight diols include ethylene glycol, 1,3 propane diol,
1,4-butanediol, 2,2-dimethyl-1,3-propylene diol, and mixtures
thereof; 1,3 propane diol and 1,4-butanediol are preferred. Useful
dicarboxylic acids include terephthalic acid, optionally with minor
amounts of isophthalic acid, and diesters thereof (e.g., <20 mol
%).
[0051] Useful thermoplastic polyesteramide elastomers that can be
used in making the core of the fibers of the invention include
those described in U.S. Pat. No. 3,468,975. For example, such
elastomers can be prepared with polyester segments made by the
reaction of ethylene glycol, 1,2-propanediol, 1,3-propanediol,
1,4-butanediol, 2,2-dimethyl-1,3-propan- ediol, 1,5-pentanediol,
1,6-hexanediol, 1,10-decandiol, 1,4-di(methylol)cyclohexane,
diethylene glycol, or triethylene glycol with malonic acid,
succinic acid, glutaric acid, adipic acid, 2-methyladipic acid,
3-methyladipic acid, 3,4-dimethyladipic acid, pimelic acid, suberic
acid, azelaic acid, sebacic acid, or dodecandioic acid, or esters
thereof. Examples of polyamide segments in such polyesteramides
include those prepared by the reaction of hexamethylene diamine or
dodecamethylene diamine with terephthalic acid, oxalic acid, adipic
acid, or sebacic acid, and by the ring-opening polymerization of
caprolactam.
[0052] Thermoplastic polyetheresteramide elastomers, such as those
described in U.S. Pat. No. 4,230,838, can also be used to make the
fiber core. Such elastomers can be prepared, for example, by
preparing a dicarboxylic acid-terminated polyamide prepolymer from
a low molecular weight (for example, about 300 to about 15,000)
polycaprolactam, polyoenantholactam, polydodecanolactam,
polyundecanolactam, poly(11-aminoundecanoic acid),
poly(12-aminododecanoic acid), poly(hexamethylene adipate),
poly(hexamethylene azelate), poly(hexamethylene sebacate),
poly(hexamethylene undecanoate), poly(hexamethylene dodecanoate),
poly(nonamethylene adipate), or the like and succinic acid, adipic
acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid,
terephthalic acid, dodecanedioic acid, or the like. The prepolymer
can then be reacted with an hydroxy-terminated polyether, for
example poly(tetramethylene ether) glycol,
poly(tetramethylene-co-2-m- ethyltetramethylene ether) glycol,
poly(propylene ether) glycol, poly(ethylene ether) glycol, or the
like.
[0053] As noted above, the wings can be formed from any
non-elastomeric, or hard, polymer. Examples of such polymers
include non-elastomeric polyesters, polyamides, and
polyolefins.
[0054] Useful thermoplastic non-elastomeric wing polyesters include
poly(ethylene terephthalate) ("2G-T") and copolymers thereof,
poly(trimethylene terephthalate) ("3G-T"), polybutylene
terephthalate ("4G-T"), and poly(ethylene 2,6-naphthalate),
poly(1,4-cyclohexylenedimet- hylene terephthalate), poly(lactide),
poly(ethylene azelate), poly[ethylene-2,7-naphthalate],
poly(glycolic acid), poly(ethylene succinate),
poly(.alpha.,.alpha.-dimethylpropiolactone),
poly(para-hydroxybenzoate), poly(ethylene oxybenzoate),
poly(ethylene isophthalate), poly(tetramethylene terephthalate,
poly(hexamethylene terephthalate), poly(decamethylene
terephthalate), poly(1,4-cyclohexane dimethylene terephthalate)
(trans), poly(ethylene 1,5-naphthalate), poly(ethylene
2,6-naphthalate), poly(1,4-cyclohexylidene dimethylene
terephthalate)(cis), and poly(1,4-cyclohexylidene dimethylene
terephthalate)(trans).
[0055] Preferred non-elastomeric polyesters include poly(ethylene
terephthalate), poly(trimethylene terephthalate), and
poly(1,4-butylene terephthalate) and copolymers thereof. When a
relatively high-melting polyesters such as poly(ethylene
terephthalate) is used, a comonomer can be incorporated into the
polyester so that it can be spun at reduced temperatures. Such
comonomers can include linear, cyclic, and branched aliphatic
dicarboxylic acids having 4-12 carbon atoms (for example
pentanedioic acid); aromatic dicarboxylic acids other than
terephthalic acid and having 8-12 carbon atoms (for example
isophthalic acid); linear, cyclic, and branched aliphatic diols
having 3-8 carbon atoms (for example 1,3-propane diol,
1,2-propanediol, 1,4-butanediol, and 2,2-dimethyl-1,3-propanediol);
and aliphatic and araliphatic ether glycols having 4-10 carbon
atoms (for example hydroquinone bis(2-hydroxyethyl)ether). The
comonomer can be present in the copolyester at a level in the range
of about 0.5 to 15 mole percent. Isophthalic acid, pentanedioic
acid, hexanedioic acid, 1,3-propane diol, and 1,4-butanediol are
preferred comonomers for poly(ethylene terephthalate) because they
are readily commercially available and inexpensive.
[0056] The wing polyester(s) can also contain minor amounts of
other comonomers, provided such comonomers do not have an adverse
affect on fiber properties. Such other comonomers include
5-sodium-sulfoisophthalat- e, for example, at a level in the range
of about 0.2 to 5 mole percent. Very small amounts, for example,
about 0.1 wt % to about 0.5 wt % based on total ingredients, of
trifunctional comonomers, for example trimellitic acid, can be
incorporated for viscosity control.
[0057] Useful thermoplastic non-elastomeric wing polyamides include
poly(hexamethylene adipamide) (nylon 6,6); polycaprolactam (nylon
6); polyenanthamide (nylon 7); nylon 10; poly(12-dodecanolactam)
(nylon 12); polytetramethyleneadipamide (nylon 4,6);
polyhexamethylene sebacamide (nylon 6,10); poly(hexamethylene
dodecanamide) (nylon 6,12); the polyamide of dodecamethylenediamine
and n-dodecanedioic acid (nylon 12,12), PACM-12 polyamide derived
from bis(4-aminocyclohexyl)methane and dodecanedioic acid, the
copolyamide of 30% hexamethylene diammonium isophthalate and 70%
hexamethylene diammonium adipate, the copolyamide of up to 30%
bis-(P-amidocyclohexyl)methylene, and terephthalic acid and
caprolactam, poly(4-aminobutyric acid) (nylon 4),
poly(8-aminooctanoic acid) (nylon 8), poly(hapta-methylene
pimelamide) (nylon 7,7), poly(octamethylene suberamide) (nylon
8,8), poly(nonamethylene azelamide) (nylon 9,9), poly(decamethylene
azelamide) (nylon 10,9), poly(decamethylene sebacamide(nylon
10,10), poly[bis(4-amino-cyclohexyl)m-
ethane-1,10-decanedicarboxamide], poly(m-xylene adipamide),
poly(p-xylene sebacamide), poly(2,2,2-trimethylhexamethylene
pimelamide), poly(piperazine sebacamide), poly(11-amino-undecanoic
acid) (nylon 11), polyhexamethylene isophthalamide,
polyhexamethylene terephthalamide, and poly(9-aminononanoic acid)
(nylon 9) polycaproamide. Copolyamides can also be used, for
example poly(hexamethylene-co-2-methylpentamethylene adipamide) in
which the hexamethylene moiety can be present at about 75-90 mol %
of total diamine-derived moieties.
[0058] Useful polyolefins include polypropylene, polyethylene,
polymethylpentane and copolymers and terpolymers of one or more of
ethylene or propylene with other unsaturated monomers. For example,
fibers comprising non-elastomeric polypropylene wings and an
elastomeric polypropylene core are within the scope of the present
invention; such fibers are bicomponent fibers.
[0059] Combinations of elastomeric and non-elastomeric polymers can
include a polyetheramide, for example, a polyetheresteramide,
elastomer core with polyamide wings and a polyetherester elastomer
core with polyester wings. For example a wing polymer can comprise
nylon 6-6, and copolymers thereof, for example,
poly(hexamethylene-co-2-methylpentamethy- lene adipamide) in which
the hexamethylene moiety is present at about 80 mol % optionally
mixed with about 1% up to about 15% by weight of nylon-12, and a
core polymer can comprise an elastomeric segmented
polyetheresteramide. "Segmented polyetheresteramide" means a
polymer having soft segments (long-chain polyether) covalently
bound (by the ester groups) to hard segments (short-chain
polyamides). Similar definitions correspond to segmented
polyetherester, segmented polyurethane, and the like. The nylon 12
can improve the wing adhesion to the core, especially when the core
is based on PEBAX.TM. 3533SN from Atofina. Another preferred wing
polymer can comprise a non-elastomeric polyester selected from the
group of poly(ethylene terephthalate) and copolymers thereof,
poly(trimethylene terephthalate), and poly(tetramethylene
terephthalate); an elastomeric core suitable for use therewith can
comprise a polyetherester comprising the reaction product of a
polyether glycol selected from the group of
poly(tetramethyleneether- ) glycol and
poly(tetramethylene-co-2-methyl-tetramethyleneether) glycol with
terephthalic acid or dimethyl terephthalate and a low molecular
weight diol selected from the group of 1,3-propane diol and
1,4-butane diol.
[0060] An elastomeric polyetherester core can also be used with
non-elastomeric polyamide wings, especially when an
adhesion-promoting additive is used, as described elsewhere herein.
For example, the wings of such a fiber can be selected from the
group of (a) poly(hexamethylene adipamide) and copolymers thereof
with 2-methylpentamethylene diamine and (b) polycaprolactam, and
the core of such a fiber can be selected from the group of (a)
polyetheresteramide and (b) the reaction products of
poly(tetramethyleneether) glycol or
poly(tetramethylene-co-2-methyltetram- ethyleneether) glycol with
terphthalic acid or dimethyl terephthalate and a diol selected from
the group of 1,3-propane diol and 1,4-butene diol.
[0061] Methods of making the polymers described above are known in
the art and may include the use of catalysts, co-catalysts, and
chain-branchers, as known in the art.
[0062] The high elasticity of the core permits it to absorb
compressional and extensional forces as it is twisted by the
attached wings when the fiber is stretched and relaxed. These
forces can cause delamination of the two polymers if their
attachment is too weak. The present invention optionally uses a
mechanical locking of the wing and core polymers to enhance the
attachment, and further minimize delamination, upon fiber
processing and use. Bonding between the core and wings can be even
further enhanced by selection of the wing and core compositions
and/or the use of adhesion-promoting additives to either or both
polymers. An adhesion promoter can be used in each or only some of
the wings. Thus, individual wings can have different degrees of
lamination to the core, e.g., some of the wings can be made to
intentionally delaminate. One example of such additive is nylon 12,
e.g., 5% by weight, based on total wing polymer, i.e.,
poly(12-dodecanolactam), also known as "12" or "N12", commercially
available as Rilsane.RTM. "AMNO" from Atofina. Also, maleic
anhydride derivatives (for example Bynel.RTM. CXA, a registered
trademark of E. I. du Pont de Nemours and Company or Lotader.RTM.
ethylene/acrylic ester/maleic anhydride terpolymers from Atofina)
can be used to modify a polyether-amide elastomer to improve it
adhesion to a polyamide.
[0063] As another example, a thermoplastic novolac resin, for
example HRJ12700 (Schenectady International), having a number
average molecular weight in the range of about 400 to about 5000,
could be added to an elastomeric (co)polyetherester core to improve
its adhesion to (co)polyamide wings. The amount of novolac resin
should be in the range of 1-20 wt %, with a more preferred range of
2-10 wt %. Examples of the novolac resins useful herein include,
but are not limited to, phenol-formaldehyde,
resorcinol-formaldehyde, p-butylphenol-formaldehyde,
p-ethylphenol-formaldehyde, p-hexylphenol-formaldehyde,
p-propylphenol-formaldehyde, p-pentylphenol-formaldehyde,
p-octylphenol-formaldehyde, p-heptylphenol-formaldehyde,
p-nonylphenol-formaldehyde, bisphenol-A-formaldehyde,
hydroxynapthaleneformaldehyde and alkyl- (such as t-butyl-) phenol
modified ester (such as penterythritol ester) of rosin
(particularly partially maleated rosin). See allowed U.S. patent
application Ser. No. 09/384,605, filed Aug. 27, 1999 for examples
of techniques to provide improved adhesion between copolyester
elastomers and polyamide.
[0064] Polyesters functionalized with maleic anhydride ("MA") could
also be used as adhesion-promoting additives. For, example,
poly(butylene terephthalate) ("PBT") can be functionalized with MA
by free radical grafting in a twin screw extruder, according to J.
M. Bhattacharya, Polymer International (August 2000), 49: 8, pp.
860-866, incorporated by reference herein, who also reported that a
few weight percent of the resulting PBT-g-MA was used as a
compatibilizer for binary blends of poly(butylene terephthalate)
with nylon 66 and poly(ethylene terephthalate) with nylon 66. For
example, such an additive could be used to adhere more firmly
(co)polyamide wings to a (co)polyetherester core of the fiber of
the present invention.
[0065] The polymers and resultant fibers, yarns, and articles used
in the present invention can comprise conventional additives, which
are added during the polymerization process or to the formed
polymer or article, and may contribute towards improving the
polymer or fiber properties. Examples of these additives include
antistatics, antioxidants, antimicrobials, flameproofing agents,
dyestuffs, light stabilizers, polymerization catalysts and
auxiliaries, adhesion promoters, delustrants, such as titanium
dioxide, mafting agents, and organic phosphates.
[0066] Other additives that may be applied on the fibers, for
example, during spinning and/or drawing processes include
antistatics, slickening agents, adhesion promoters, hydrophilic
agents antioxidants, antimicrobials, flameproofing agents,
lubricants, and combinations thereof. Moreover, such additional
additives may be added during various steps of the process as is
known in the art.
[0067] While the above description focuses on advantages when the
fiber has a substantially radially symmetric cross-section, such
symmetry, while often desired, is not required for embodiments of
the invention where:
[0068] (a) the stretchable synthetic polymer fiber has a
delamination rating of less than about 1 and an after boil-off
shrinkage of at least about 20%.
[0069] (b) the stretchable synthetic polymer fiber has at least
about 20% after boil-off shrinkage and requires less than about 10%
stretch to substantially straighten the fiber;
[0070] (c) the stretchable synthetic polymer fiber comprises an
axial core comprising an elastomeric polymer and a plurality of
wings comprising a non-elastomeric polymer attached to the core,
wherein the core includes on its outside surface a sheath of a
non-elastomeric polymer between points where the wings contact the
core;
[0071] (d) the stretchable synthetic polymer fiber comprises an
axial core comprising an elastomeric polymer and a plurality of
wings comprising a non-elastomeric polymer attached to the core,
wherein the core has a substantially circular or regular polyhedron
cross section; or
[0072] (e) the stretchable synthetic polymer fiber comprises an
axial core comprising an elastomeric polymer and a plurality of
wings comprising a non-elastomeric polymer attached to the core,
wherein at least one of the wings has a T, C, or S shape.
[0073] The free biconstituent fibers (i.e., biconstituent fibers
having little resistive force thereon) can have an after-boil-off
stretch of at least about 20%, preferably of at least about 45% for
improved comfort and fit in the final garment. The boil-off stretch
of a fabric will depend on its construction, and the degree of
constraint on the fiber in the fabric environment. Generally, the
more of freedom from constraint and jamming the fiber sees in the
fabric, the more stretch and recoery it can generate in fabric
form.
[0074] The fibers of the invention can be in the form of continuous
filament (either a multifilament yarn or a monofilament) or staple
(including for example tow or spun yarn). The drawn fibers of the
invention can have a denier per fiber of from about 1.5 to about 60
(about 1.7-67 dtex). Fully drawn fibers of the invention with
polyamide wing typically have tenacities of about 1.5 to 3.0
g/dtex, and fibers with polyester wing, about 1-2.5 g/dtex,
depending on wing/core ratios.
[0075] When a yarn comprising a plurality of fibers is made, the
fibers can be of any desired fiber count and any desired dpf, and
the ratios of the elastomeric to non-elastomeric polymers can
differ from fiber to fiber. The multifilament yarn can contain a
plurality of different fibers, for example, from 2 to 100 fibers.
In addition, yarns comprising the fibers of the present invention
can have a range of linear densities per fiber and can also
comprise fibers not of the invention.
[0076] The process for making the biconstituent fibers of the
present invention will be described with respect to FIG. 5, which
is a schematic of an apparatus which can be used to make the fibers
of the present invention. However, it should be understood that
other apparatus may be used. The process of the present invention
comprises passing a melt comprising an elastomeric polymer through
a spinneret to form a plurality of stretchable synthetic polymeric
fibers including an axial core comprising the elastomeric polymer
and a plurality of wings attached to the core and comprising the
non-elastomeric polymer. With reference to FIG. 5, a thermoplastic
hard polymer supply, which is not shown, is introduced at 20 to a
spin pack assembly 30, and a thermoplastic elastomeric polymer
supply, which is not shown, is introduced at 22 to spin pack
assembly 30. Precoalescence or post coalescence spinneret packs can
be used. The two polymers can be extruded as undrawn filaments 40
from a stacked plate spinneret assembly 35 having orifices designed
to give the desired cross section. The process of the present
invention further includes quenching the filaments after they exit
the capillary of the spinneret to cool the fibers in any known
manner, for example by cool air at 50 in FIG. 5. Any suitable
quenching method may be used, such as cross-flow air or radially
flowing air.
[0077] The filaments are optionally treated with a finish, such as
silicone oil optionally with magnesium stearate using any known
technique at a finish applicator 60 as shown in FIG. 5. These
filaments are then drawn, after quenching, so that they exhibit at
least about 20% after boil-off stretch. The filaments may be drawn
in at least one drawing step, for example between a feed roll 80
(which can be operated at 150 to 1000 meters/minute) and a draw
roll 90 shown schematically in FIG. 5 to form a drawn filament 100.
The drawing step can be coupled with spinning to make a fully-drawn
yarn or, if a partially oriented yarn is desired, in a split
process in which there is a delay between spinning and drawing.
Drawing can also be accomplished during winding the filaments as a
warp of yarns; called "draw warping" by those skilled in the art.
Any desired draw ratio, (short of that which interferes with
processing by breaking filament) can be imparted to the filament,
for example, a fully oriented yarn can be produced by a draw ratio
of about 3.0 to 4.5 times, and a partially oriented yarn produced
by a draw ratio of about 1.2-3.0 times. Herein, draw ratio is the
draw roll 90 peripheral speed divided by the feed roll 80
peripheral speed. Drawing can be carried out at about
15-100.degree. C., typically about 15-40.degree. C.
[0078] The drawn filament 100 optionally can be partly relaxed, for
example, with steam at 110 in FIG. 5. Any amount of heat-relaxation
can be carried out during spinning. The greater the relaxation, the
more elastic the filament, and the less shrinkage that occurs in
downstream operations. The drawn, final filament, after being
relaxed as described below, can have at least about 20% after
boil-off stretch. It is preferred to heat-relax the just-spun
filament by about 1-35% based on the length of the drawn filaments
before winding it up, so that it can be handled as a typical hard
yarn.
[0079] The quenched, drawn, and optionally relaxed filaments can
then be collected by winding at a speed of 200 to about 3500 meters
per minute and up to 4000 meters per minute, at winder 130 in FIG.
5. Or if multiple fibers have been spun and quenched, the fibers
can be converged, optionally interlaced, and then wound up for
example at up to 4000 meters per minute at winder 130, for example
in the range of about 200 to about 3500 meters per minute. Single
filament or multifilament yarns may be wound up at winder 130 in
FIG. 5, in the same manner. Where multiple filaments have been spun
and quenched, the filaments can be converged and oprtionally
interlaced prior to winding as is done in the art.
[0080] At any time after being drawn, the biconstituent filament
may be dry- or wet-heattreated while fully relaxed to develop the
desired stretch and recovery properties. Such relaxation can be
accomplished during filament production, for example during the
above-described relaxation step, or after the filament has been
incorporated into a yarn or a fabric, for example during scouring,
dyeing, and the like. Heat-treatment in fiber or yarn form can be
carried out using hot rolls or a hot chest or in a jet-screen
bulking step, for example. It is preferred that such relaxed
heat-treatment be performed after the fiber is in a yarn or a
fabric so that up to that time it can be processed like a
non-elastomeric fiber; however, if desired, it can be heat-treated
and fully relaxed before being wound up as a high-stretch fiber.
For greater uniformity in the final fabric, the fiber can be
uniformly heat-treated and relaxed. The heat-treating/relaxation
temperature can be in the range of about 80.degree. C. to about
120.degree. C. when the heating medium is dry air, about 75.degree.
C. to about 100.degree. C. when the heating medium is hot water,
and about 101.degree. C. to about 115.degree. C. when the heating
medium is superatmospheric pressure steam (for example in an
autoclave). Lower temperatures can result in too little or no
heat-treatment, and higher temperatures can melt the elastomeric
core polymer. The heat-treating/relaxation step can generally be
accomplished in a few seconds.
[0081] The biconstituent yarns can be wound up to hard yarns
(non-elastic yarn), since the as spun, biconstituent yarn shows
elongation and stretch properties consistent with their hard yarn
lobe component. That is, the individual lobe portions about the
elastomer core are generally straight and parallel to the filament
direction as spun. Yarn or fabrics or other articles constructed
from these yarns can be finished with heat. This heat treatment
causes the lobe portions to spiral around the elastomer core.
Substantial shrinkage of the biconstituent yarn takes place, as
much as 1/3 to 1/2 of the filament spun length is reduced. As a
result, there is development of a high level of stretch and
recovery. The percent stretch of the yarn after finishing will be a
function of the differential in shrinkage of the biconstituent and
companion yarn since the biconstituent develops recoverable
shrinkage (after boil-off stretch), but can only stretch to the
point where the hard yarn is fully engaged. Stretch and recovery is
evaluated subjectively by pulling on the fabrics and observing that
the fabrics return to their original shape when the fabric is
released.
[0082] As noted above, the spinneret capillary has a design
corresponding to the desired cross-section of the fibers of the
present invention, as described above, or to produce other
biconstituent or bicomponent fibers. The capillaries or spinneret
bore holes may be cut by any suitable method, such as by laser
cutting, as described in U.S. Pat. No. 5,168,143, drilling,
Electrical Discharge Machining (EDM), and punching, as is known in
the art. The capillary orifice can be cut using a laser beam for
good control of the cross-sectional symmetry of the fiber of the
invention. The orifices of the spinneret capillary can have any
suitable dimensions and can be cut to be continuous
(pre-coalescence) or non-continuous (post-coalescence). A
non-continuous capillary may be obtained by boring small holes in a
pattern that would allow the polymer to coalesce below the
spinneret face and form the multi-wing cross-section of the present
invention.
[0083] For example, the filaments of the invention can be made with
a precoalescence spinneret pack as illustrated in FIGS. 6, 6A, 6B
and 6C. In FIG. 6, a side elevation of the spinneret assembly
stacked plates as shown in FIG. 5, the polymer flow is in the
direction of arrow F. The first plate in the spinneret assembly is
plate D containing the polymer melt pool and is of a conventional
design. Plate D rests upon metering plate C (shown in cross
sectional view FIG. 6C), which in turn rests upon optional
distribution plate B (shown in cross sectional view FIG. 6B), which
rests on spinneret plate A (shown in cross sectional view FIG. 6A),
which is supported by spinneret assembly support plate E. Metering
plate C is aligned and in contact with distribution plate B below
the metering plate, the distribution plate being above, aligned
with, and in contact with spinneret plate A having capillaries
there through but lacking substantial counterbores, the spinneret
plate(s) being aligned and in contact with a spinneret support
plate (E) having holes larger than the capillaries. The alignments
are such that a polymer fed to the metering plate C can pass
through distribution plate B, spinneret plate A and spinneret
support plate E to form a fiber. Melt pool plate D, which is a
conventional plate, is used to feed the metering plate. The polymer
melt pool plate D and spinneret assembly support plate E are
sufficiently thick and rigid that they can be pressed firmly toward
each other, thus preventing polymer from leaking between the
stacked plates of the spinneret assembly. Plates A, B, and C are
sufficiently thin that the orifices can be cut with laser light
methods. It is preferred that the holes in the spinneret support
plate (E) be flared, for example at about 45.degree.-60.degree., so
that the just-spun fiber does not contact the edges of the holes.
It is also preferred that, when precoalescence of the polymers is
desired, the polymers be in contact with each other
(precoalescence) for less than about 0.30 cm, generally less than
0.15 cm, before the fiber is formed so that the cross-sectional
shape intended by the metering plate C, optional distribution plate
D, and spinneret plate design E is more accurately exhibited in the
fiber. More precise definition of the fiber cross-section can also
be aided by cutting the holes through the plates as described in
U.S. Pat. No. 5,168,143, in which a multi-mode beam from a
solid-state laser is reduced to a predominantly single-mode beam
(for example TM.sub.00 mode) and focused to a spot of less than 100
microns in diameter and 0.2 to 0.3 mm above the sheet of metal. The
resulting molten metal is expelled from the lower surface of the
metal sheet by a pressurized fluid flowing coaxially with the laser
beam. The distance from the top of the uppermost distribution plate
to the spinneret face can be reduced to less than about 0.30
cm.
[0084] To make filaments having any number of symmetrically placed
wing polymer portions, the same number of symmetrically arranged
orifices are used in each of the plates. For example in FIG. 6A,
spinneret Plate A is shown in a plan view oriented 90.degree. to
the stacked plate configuration of FIG. 5. Plate A in FIG. 6A is
comprised of six symmetrically arranged wing spinneret orifices 140
connected to a central round spinneret hole 142. Each of the wing
orifices 140 can have different widths 144 and 146. Shown in FIG.
6B is the complementary distribution Plate B having distribution
orifices 150 tapering at an open end 152 to optional slot 154
connecting the distribution orifices to central round hole 156.
Shown in FIG. 6C is metering Plate C with metering capillaries 160
for the wing polymer and a central metering capillary 162 for the
core polymer. Polymer melt pool Plate D can be of any conventional
design in the art. Spinneret support Plate E has a through hole
large enough and flared away (for example at 45-60.degree.) from
the path of the newly spun filament so that the filament does not
touch the sides of the hole, as is shown in FIGS. 7 and 8 side
elevation. The stacked Plate Assembly, Plates A through D, are
aligned so that core polymer flows from polymer melt pool Plate D
through central metering hole 162 of metering Plate C and through
the 6 small capillaries 164, through central circular capillary 156
of distribution Plate B, through central circular capillary 142 of
spinneret assembly Plate A, and out through large flared hole in
spinneret support Plate E. At the same time, wing polymer flows
from polymer melt pool Plate D through wing polymer metering
capillaries 160 of metering Plate C, through distribution orifices
150 of distribution Plate B (in which, if optional slot 154 is
present, the two polymers first make contact with each other),
through wing polymer orifices 140 of spinneret Plate A, and finally
out through the hole in spinneret assembly support Plate E.
[0085] The spinneret pack of the invention can be used for the melt
extrusion of a plurality of synthetic polymers to produce a fiber.
In the spinneret pack of the present invention, the polymers can be
fed directly into the spinneret capillaries, since the spinneret
plate does not have a substantial counterbore. By no substantial
counterbore is meant that the length of any counterbore present
(including any recess connecting the entrances of a plurality of
capillaries) is less than about 60%, and preferably less than about
40%, of the length of the spinneret capillary. See FIG. 7A, which
shows a cross-sectional of a spinneret plate of the prior art and
FIGS. 7B and C, which shows a cross-section of spinneret plates of
the present invention. Directly metering multicomponent polymer
streams into specific points at the backside entrance of the fiber
forming orifice in the spinneret plate eliminates problems in
polymer migration when multiple polymer streams are combined in
feed channels substantially before the spinneret orifice, as is the
norm.
[0086] It can be useful to combine the functions of two plates into
one through the use of recessed grooves, on one or both sides of
the single plate with appropriate holes through the plate to
connect the grooves. For example, recesses, grooves and depressions
can be cut in the upstream side of the spinneret plate (for example
by electrodischarge machining) and can function as distribution
channels or shallow, insubstantial counterbores.
[0087] A variety of fibers comprising two or more polymers can be
made with the spinneret pack of the present invention. For example,
other biconstituent fibers and bicomponent fibers not disclosed
and/or claimed herein can be so made, including the cross-sections
disclosed in U.S. Pat. Nos. 4,861,660, 3,458,390, and 3,671,379.
The resulting fiber cross-section can be for example side-by-side,
eccentric sheath-core, concentric sheath-core, wing-and-core,
wing-and-sheath-and core, and the like. Moreover, the spinneret
pack of the invention can be used to spin splittable or
non-splittable fibers.
[0088] The spinneret pack of the invention can be modified to
achieve different multiwinged fibers, for example, by changing the
number of capillary legs for a different desired wing count,
changing slot dimensions to change the geometric parameters as
needed for production of a different denier per filament or yarn
count, or as desired for use with various synthetic polymers. For
example, in the embodiment of FIG. 8 is shown a relatively thin
spinneret pack used to make a fiber with three wings. In FIG. 8A,
the spinneret plate was 0.015 inches (0.038 cm) thick and had
orifices machined through the full thickness of stainless steel, by
the laser light methods herein disclosed, in the form of three
straight wings 140 each of two widths (having lengths 144 and 146
respectively) and arranged symmetrically at 120 degrees apart
around a center of symmetry; there was no counterbore above the
capillary orifice. Each wing 140 was 0.040 inches (0.102 cm) long
from its tip to the circumference of a central round spinneret hole
142 of 0.012 inches (0.030 cm) diameter whose center coincided with
the center of symmetry. Referring next to FIG. 8B, distribution
plate B, of 0.010 inch (0.025 cm) thickness, was coaxially aligned
over spinneret plate A so that every other wing orifice 150 of
distribution plate B was aligned with a wing 140 of spinneret plate
A; each wing orifice 150 of distribution plate B was 0.1375 inches
(0.349 cm) long from its tip to the center of symmetry. Metering
plate C (FIG. 10C) was 0.010 (0.025 cm) inches thick and had holes
160 of 0.025 inch (0.064 cm) diameter, holes 162 of 0.015 inch
(0.038 cm) diameter, and central hole 164 of 0.010 inch (0.025 cm)
diameter. Plate C was aligned with distribution plate B so that, in
use, wing polymer fed by melt pool plate D (see FIG. 8) to holes
160 and core polymer fed to holes 162 and 164 of distribution plate
C were distributed by plate B to plate A to form a fiber, in which
the wings penetrated the core. There was no counterbore in
spinneret plate A, and the combined thickness of plates A, B, and C
was only about 0.035 inches (0.089 cm).
[0089] In another spinneret pack assembly embodiment, no spinneret
support plate E (see FIG. 8) was used. In FIG. 9A, spinneret plate
A was 0.3125 inch (0.794 cm) thick, and each spinning orifice had
an 0.100 inch (0.254 cm) diameter counterbore and an 0.015 inch
(0.038 cm) long capillary at the bottom of the counterbore. As
shown in FIG. 9A, each spinneret orifice in spinneret plate A had
six straight wing orifices 170, each of which had a long axis
centerline which passed through a center of symmetry and had a
length of 0.035 inch (0.089 cm) from its tip to the circumference
of central round hole 172. Length 174 from the tip of each wing to
0.015 inch (0.038 cm) was 0.004 inch (0.010 cm) wide; length 176
was 0.020 inch (0.051 cm) long and 0.0028 inch (0.007 cm) wide. The
tip of each wing was radius-cut at one-half the width of the tip.
Distribution plate B (see FIG. 9B) was 0.015 inch (0.038 cm) thick
and had six-wing orifices, each of which was centered above a
corresponding counterbore in spinneret plate A and oriented so that
each wing orifice in plate B was aligned with a wing orifice of
plate A. Each wing orifice 150 in plate B was 0.060 inch (0.152 cm)
long and 0.020 inch (0.051 cm) wide, and its tip was rounded to a
radius of 0.010 inch (0.025 cm). Central hole 152 in plate B was
0.100 inch (0.254 cm) in diameter. Metering plate C (see FIG. 9C)
was also 0.015 inch (0.038 cm) thick. In plate C, holes 160 had a
diameter of 0.008 inch (0.020 cm) and were 0.100 inch (0.254 cm)
from the center of central hole 162, which of plates B and A and
formed the core of the fiber. Non-elastomeric wing polymer was fed
to holes 160 in plate C and passed through the wing orifices of
plates B and A to form the wings of the fiber. Wing and core
polymers first make contact at the top of distribution plate B,
which is 0.328 inch (0.833 cm) above the face of spinneret plate A
from which the fiber is extruded was 0.080 inch (0.203 cm) in
diameter. Plate C was aligned with plate B so that the six holes
160 of plate C were above the centerlines of the wing orifices 150
of plate B. The plates were aligned so that elastomeric core
polymer fed to hole 162 of plate C passed through the center.
[0090] The hetero-composite yarn of the present invention also
comprises a companion yarn, which is shown at 20 in FIG. 1. The
hetero-composite yarn comprises a man-made or natural fiber. This
companion yarn is any yarn other than the same biconstituent yarn
and preferably has lower shrinkage than the biconstituent yarn. The
companion yarn can be formed of a man-made, fiber-forming,
melt-spinnable polymers including, but not limited to, polyamides,
polyolefins, such as polyethylene and polypropylene, polyesters,
viscose polymers, such as rayon, and acetate, or combinations
thereof. The polyamides, polyesters, polyolefins, and bicomponents
used in the companion yarn can be selected from any of such
polymers known, including those discussed above with reference to
the wings of the biconstituent filaments. The polymers used to make
up the companion yarn may have any cross-sectional shape. The
cross-sectional shapes, for example, may include round, oval,
trilobal shapes with higher numbers of symmetric or unsymmetric
lobes, and dog-bone shaped. In addition, the companion yarn may be
or include natural fibers, such as cotton, wool, and/or silk.
Preferred companion yarns include nylon, polyester, polyolefin,
rayon, cotton and wool. Examples of commercially available
companion yarns include DuPont nylon TACTEL.RTM. products known in
the industry as Multisoft, Microdeniers and Diablo. Also,
especially useful is any yarn that lends itself to air-entangling,
or air-jet texturing or carding (for staple). Additives or
treatments, such as discussed above with reference to the
biconstituent yarn, can be used with the companion yarn. The choice
of the companion yarn is broad; generally its aesthetic impact in
fabric guides that decision.
[0091] Preferably, the companion yarn is less elastomeric than the
polymer of the core. Also, the companion yarn generally has lower
shrinkage than the biconstituent filament. The companion yarn may
be a single fully drawn or hard yarn, or a bicomponent yarn or
another biconstituent yarn. For example, combining a biconstituent
of lower shrinkage and percent recoverable stretch (after boil-off
stretch), with a biconstituent of higher shrinkage and percent
recoverable stretch could be advantageous, for example, to provide
yarns of certain composite stretch and recovering properties. If
two biconstituent yarns are combined then there would likely not be
a self-bulking effect, since neither biconstituent generates bulk
upon stretching.
[0092] Where the companion yarn is a single component drawn yarn,
it has been found that yarns having less than about 80% elongation
to break, preferably less than about 60% elongation to break, more
preferably less than about 50% elongation to break, measured using
standard ASTM intron technique D2256 (or TRL-TM1356) are
particularly useful for the present invention.
[0093] The combined biconstituent yarn and the companion yarn may
be present in the final product in varying ratios depending on the
intended use, for example, the weight ratio of the two yarns can
range from about 90/10: about 10/90, more preferably 80/20 to
20/80. The fraction of each of the components of the final product
may be measured, e.g., according to its total denier and denier per
filament. The greater the total denier or denier per filament, the
greater the amount of the component in the final product. Modifying
the components based upon these factors may achieve different
functions of the final product. For example, a higher stretch and
recovery power may be obtained by having a greater fraction of the
biconstituent yarn in the final product. Conversely, a fabric
having less stretch and recovery power may be obtained by having a
greater fraction of the second yarn, where the companion yarn is a
single component yarn.
[0094] As noted above, the biconstituent yarn of the present
invention can be a monofilament yarn or formed from a plurality of
filaments, for example 2 to 60 filaments. The companion yarn can be
formed from, e.g., 2-60 filaments. When the hetero-composite yarn
comprises a plurality of biconstituent fibers, the biconstituent
fibers can be of different, e.g. decitexes, and the ratios of the
elastomeric to non-elastomeric polymers can differ from fiber to
fiber.
[0095] The denier per filament of the biconstituent fiber is
preferably less than 50, more preferably less than 20, most
preferably less than 10 and the denier per filament of the
composite yarn is preferably less than 10, more preferably less
than 5, most preferably less than 2.5, e.g., about 0.5 to about 50
dpf. The dpf of the filaments within the yarn bundle is a key
determinant for softness, hand, and other apparel fabric
attributes; winged biconstituent yarns often have an apparent dpf,
based on tactility and fabric hand, which is less than their real
dpf. For instance, a 20 dpf filament fabric may feel as soft at a
5-10 dpf multifilament yarn in fabric form. Nevertheless, it is
often useful for the biconstituent dpf to exceed the companion yarn
dpf so dramatically if tactility and uniformity are critical.
[0096] The total denier of the hetero-composite yarn can range from
about 20 to about 300 denier for typical apparel applications.
Industrial, upholstery or flooring applications may range from 100
to several thousand denier. Preferred companion yarns are 10-300
total denier for apparel and 300 to 3000 denier for upholstery;
more preferably 20-200 total denier; and filament counts consistent
with denier per filaments of 0.5-50; more preferably 1.0 to 10 for
apparel.
[0097] When the hetero-composite yarn of the present invention has
low denier, it may be used for making fine fabrics, while a yarn
having high denier may be used for heavier fabrics. Accordingly,
the yarn of the present invention may have any yarn denier suitable
for its final end use product. For fine fabrics, the yarn may have
a sum denier of the combination of the biconstituent denier and the
companion yarn of less than about 60, preferably less than about
50, and more preferably, less than about 40 to as low as 10 denier.
For medium weight fabrics, the hetero-composite yarn may have a
denier of between about 50 to about 200, preferably about 70 to
about 150, and more preferably about 70 to about 140. For heavier
fabrics, such as load-bearing fabrics, the hetero-composite yarn
may have a denier of between about 200 to about 2400, preferably
about 200 to about 2000.
[0098] The hetero-composite yarns of the present invention are
preferably self-bulking. This means that they are formed from
biconstituent filaments that exhibit high shrinkage on finishing
(the biconstituent portion), and the companion filaments which have
less shrinkage. The biconstituent filaments generally will show
20-100% recoverable stretch (after boil-off stretch), with
preferably greater than 25%, and preferably greater than 50%. Also,
the biconstituent filaments will generally show 10-30%
non-recoverable shrinkage, preferably less than 30%, and more
preferably less than 25%. The lower shrinkage companion yarn
filaments will generally show 1-15% non-recoverable shrinkage. When
the biconstituent, high shrinkage filaments are activated (shrink),
the companion yarn bends and enhances the bulk of the composite
yarn. Thus, the yarns shrink in length substantially in textile
finishing processes (hot, wet treatments) and gain in volume
cubically. The hetero-composite yarn of the present invention shows
high stretch recovery, that is, after stretching 20% to 100% of
their initial relaxed length after boil-off, they readily recover
to near their original relaxed length.
[0099] The hetero-composite yarn can be handled like a hard yarn
without the need for special tensioning. After finishing, there is
provided true elastomeric recovery properties; that is, the surface
of the yarn is integral and dyeable in the same manner as the
companion hard yarns. The hetero-composite yarn is amenable to
larger package size since it is in hard yarn form, and has a
non-tacky hard yarn surface.
[0100] A wide variety of aesthetics and hand can be obtained from
the hetero-composite yarns of the present invention. These effects
will depend, e.g., on the nature of the companion yarn (e.g., dpf,
filament x-sectional shape, total denier, shrinkage), the
particular biconstituent yarn composition, the ratio of the
components, and the manner of combining used. The hetero-composite
yarns have the property of processing like hard yarns, and
generating stretch and elastomer driven recovery through heat or
hot/wet processing. If yarns are selected such that the
biconstituent wings, and the companion yarns are from a similar
polymer families, excellent dye uniformity can be achieved.
Alternatively, different polymer families can be employed to
generate heathering effects in combination with good stretch and
recovery.
[0101] The hetero-composite yarns may be used to form fabrics by
known methods including by circular, warp, or flat knitting,
seamless knitting, hosiery knitting, by weaving as weft yarn, or
warp yarn, or both. Yarns may be in the form of continuous
filaments or pre-combining in the form of staple yarns.
[0102] Further in accordance with the present invention, there is
provided a process of making a hetero-composite yarn. The process
comprises commingling a biconstituent yarn with a companion yarn.
The biconstituent yarn comprises at least one filament with an
axial core comprising a thermoplastic elastomeric polymer and a
plurality of wings attached to the core, the wings comprising a
thermoplastic, non-elastomeric polymer. FIG. 10 is a schematic of a
process for spinning a biconstituent yarn, spinning a companion
yarn and commingling the biconstituent yarn and the companion
yarn.
[0103] Following FIG. 10, a first hard thermoplastic polymer, from
a source not shown, is introduced at 5 and a second elastic
thermoplastic polymer, from a source not shown, is introduced at
15. The first and second polymers are combined in a spin pack
distribution body 25 and extruded from bicomponent spinneret 35 to
form a biconstituent filament, such as a monofilament 45. This
biconstituent filament is quenched, i.e., cooled and solidified by
a cross flow of air 55 and then oiled with a fiber finish
composition at 65 and wound up into a package of monofilament yarn
at 95.
[0104] On the right side of FIG. 10, a hard thermoplastic polymer
from a source not shown, is introduced at 18 and directed through
spin pack 20 and extruded through a multicapillary spinneret plate
30 to form a plurality of companion yarns 40 which are cooled and
solidified by a cross flow of air 50 and converged into a
multifilament yarn at 60 where the yarn is oiled with a fiber
finish and forwarded through an entangling device 70, providing
good filament cohesion to the yarn bundle, and into a draw zone
between feed roll 80 and draw roll 90, the yarn 100 is drawn by
factor equal to the ratio of the surface speed of roll 90 versus
roll 80, and pulled through yarn entangling device 110 by the
winder to form a yarn package 120. Optionally yarn 100 can be
undrawn, in which case roll speed 90 is equal to that of 80.
[0105] The process of the present invention may comprise an
additional step, after quenching, of heat-relaxing the fiber so
that it exhibits at least about 20% after boil-off stretch. The
heat-relaxing is carried out with a heating medium of dry air, hot
water or superatmospheric pressure steam at a temperature in the
range of about 80.degree. C. to about 120.degree. C. when the
heating medium is said dry air, about 75.degree. C. to about
100.degree. C. when the heating medium is said hot water, and about
101.degree. C. to about 115.degree. C. when the heating medium is
said superatmospheric pressure steam.
[0106] The biconstituent yarn and the companion yarn can be
combined in any form, in either filament or yarn format, or even
before the filament format, in or before the spinneret. In FIG. 11
a process is illustrated for combining the biconstituent filament
yarn from a yarn package with the companion yarn from a yarn
package by use of an entangling device. Taken together, the process
of FIG. 11, along path C, and the process of FIG. 10 provide a
method for making the hetero-composite yarn of the invention in a
two-stage (split) process. In FIG. 11 the biconstituent yarn 45
from package 95 and the hard yarn 100 from package 120 are combined
using change of direction rolls 106 and 108 to forward yarns 45 and
100 through an air jet entangling device 110 to form a
hetero-composite yarn 112 wound on package 130.
[0107] In FIG. 12 a process scheme for spinning the biconstituent
filament along path A and B is depicted along with a process for
spinning the companion yarn, in a two-stage (split) process. The
elements in FIG. 12 which are common to FIG. 10 are the same as
those described above with respect to FIG. 10. In this process
variation, the biconstituent yarn in its hard yarn configuration is
spun separately and spooled from a production package 75 or 85
directly into the spinning process of the companion yarn following
either path A or path B. In the companion yarn process, the
biconstituent is entangled with the companion yarn by an
intermingling jet (not shown) of the companion yarn process. The
hetero-composite yarn so formed is wound onto a single yarn package
130.
[0108] As discussed above, the invention combines the biconstituent
yarn with the companion yarn to form a single yarn. Each of the
biconstituent yarn and combined yarn may be made separately
off-line and then combined to form the final synthetic yarn, or one
or both may be made on-line in a continuous manner. Combining these
components to form a single yarn may be conducted by any known
method, including plying, co-spinning, air jet texturing, air false
twist texturing, and covering. Plying is simple combining by laying
yarns together without mixing of filaments. Plying may be conducted
by twisting the yarns together in a draw twister. Typically, the
yarns may be twisted at about 0-5 turns-per-inch (tpi), and
preferably, 1/4-1/2 tpi. Co-spinning is combining by laying yarns
together in the spinning process; up to, for example, 4000 meters
per minute. Co-spinning may be conducted by commingling yarns in an
interlaced jet. Air entangling is a process that causes filaments
of the biconstituent and second yarn to become intermingled;
typically processing speed is 500 to 1000 meters per minute. Air
jet texturing is a process where two yarn are fed to an air jet
texturing apparatus; typically one yarn is over-fed (effect yarn)
with respect to the other (core yarn). The effect yarn is crimped
and bulked and entangled with the core yarn. 100 to 400 meters per
minute is a typical speed. Air jet texturing may be conducted by
overfeeding the biconstituent yarn and the companion yarn through
an air jet texturing machine at different speeds to create a
bulkier yarn entangled at nodes along the end. Core spinning is a
process where a staple yarn is spun and wrapped around a core yarn
to cover the core yarn. Mechanical covering is a process where a
continuous yarn is mechanical wrapped around a core yarn. If the
yarns are combined by covering, either the biconstituent yarn or
the companion yarn may be used to wrap the other yarn. However, to
maximize stretch potential, it is preferable to use the
biconstituent as the core yarn. Combining can also be accomplished
by. the serial process of false twist texturing a hard yarn
followed by co-entangling with the biconstituent yarn prior to
package winding.
[0109] There also can be used co-stretch breaking technology as
disclosed in WO77283, or there can be used as methods for combining
the yarn with variations in entangling or twisting a long the end
that creating "fancy" bulked yarn effects. Staple blends can be
created using specialized equipment similar to that used in the
worsted yarn industry for "stretch-breaking" continuous filament
yarns. Biconstituent and companion yarns in continuous form can be
feed into a series of nip rollers running at sufficiently different
speeds, with sufficient nip force, that the individual filaments
within the yarn bundle are pulled to the breaking point creating a
staple yarn, while the continuity of the overall yarn bundle in
maintained, in a continuous operation. Such yarns can be blended on
worsted combing machines to create a hetero-composite-staple
composite yarn which can be drawn and twisted into a finer
yarn.
[0110] In the process of the present invention as described above,
the biconstituent yarn and the companion yarn are either fully
drawn or partially drawn during processing. The intermingling of
the biconstituent and companion yarn can be accomplished by,
e.g.,:
[0111] (a) intermingling of two partially oriented yarn (POY)
followed by drawing,
[0112] (b) intermingling of two drawn yarns, or
[0113] (c) some combination of these.
[0114] In one method, a biconstituent yarn in its hard yarn as-spun
configuration is combined with the companion yarn. Both yarns are
spun separately and intermingled with entangling jets in a separate
step. The hetero-composite yarn so formed is wound onto a single
yarn package. Typical intermingling speed can range from about 600
to about 800 meter per minute.
[0115] In a second method, the biconstituent yarn in its hard yarn
configuration is spun separately and spooled from a production
package directly into the spinning process of the companion yarn.
The biconstituent yarn is entangled with the companion yarn by the
intermingling jet of the second yarn process. The hetero-composite
yarn so formed is wound onto a single yarn package. Typical wind up
speed can be about 1500 to about 4000 meters per minute.
[0116] In a third method, an integrated single-stage process is
used. The threadlines of the biconstituent and the companion yarn
are brought together and intermingled before winding up a
hetero-composite yarn. Intermingling speed can range from about 600
to about 800 meters per minute.
[0117] In a fourth method a two-stage or optionally, an integrated
single-stage process is used. Here the biconstituent yarn and the
companion yarn are partially drawn (e.g., both yarns are partially
oriented yarns (POY)) during their production and both yarns
combined and entangled by use of the intermingling jet of the
companion yarn process. Intermingling speed could be accomplished
by e.g., second spinning speeds at a feed roll of about 600 to
about 1000 meter per minute and wound up after drawing at wind up
speeds of about 2000 to about 4000 meters per minute.
[0118] In a fifth method, the biconstituent yarn is partially drawn
(e.g. a POY) and the second yarn is fully drawn during production
and both yarns combined and entangled by an intermingling jet of
the companion yarn process.
[0119] In a sixth method, the biconstituent yarn is fully drawn in
production and the companion yarn is partially drawn (e.g., a POY)
during production. Both yarns are combined and entangled by an
intermingling jet of the companion yarn process.
[0120] Combining can also include covering by wrapping one yarn
around the other yarn. If the yarns are combined by covering,
either the biconstituent yarn or the companion yarn may be used to
wrap the other yarn.
[0121] The hetero-composite yarn process eliminates the elastomeric
yarn covering process and the false twist texturing processes used
for conventional fabric production. The process of the invention
provides an integrated melt spun yarn and selection of aesthetics,
combined with a selection of bulk and stretch and recovery
properties.
[0122] The invention is illustrated by the following non-limiting
examples.
Test Methods
[0123] Stretch properties (after boil-off stretch, after boil-off
shrinkage and stretch recovery after boil-off) of the fibers
prepared in the Examples below were determined as follows. A 5000
denier (5550 dtex) skein was wound on a 54 inch (137 cm) reel. Both
sides of the looped skein were included in the total denier.
Initial skein lengths with a 2 gram weight (length CB) and with a
1000 gram weight (0.2 g/denier) (length LB) were measured. The
skein was subjected to 30 minutes in 95.degree. C. water ("boil
off"), and initial (after boil off) lengths with a 2 gram weight
(length CA.sub.initial) and with a 1000 gram weight (length
LA.sub.initial) were measured. After measurement with the 1000 gram
weight, additional lengths were measured with a 2 gram weight after
30 seconds (length CA.sub.30 sec) and after 2 hours (length
CA.sub.2hrs). Shrinkage after boil-off was calculated as
100.times.(LB-LA)/LB. Percent after boil-off stretch was calculated
as 100.times.(LA-CA@30 sec)/CA@30 sec. Recovery after boil-off was
calculated as 100.times.(LA-CA.sub.2 hrs)/(LA-CA.sub.initial).
EXAMPLES
Example 1
Air Entangled Biconstituent Composite Yarns in Knit Fabric
[0124] An air entangled hetero-composite-yarn with latent stretch
and recovery properties was created by air entangling a first a
mono-filament biconstituent yarn of the present invention with a
second commercially available companion yarn.
Biconstituent Yarn Spinning
[0125] The biconstituent yarn was spun as a 19 denier (21 dtex) per
filament produced as in Path C of FIG. 1. Other fiber and spinning
characteristics were as follows:
1 Denier 19 #filaments 1 Wing/core interpenetration yes Feed Roll
Speed (m/min) 420 Primary Finish none Primary Finish % 0 Secondary
Finish type K-9349 Secondary Finish % 4% Wing Polymer Camacari N6
DuPont Brazilia SA Additive in wing polymer 5% Nylon 12 Rilson AMNA
Atofina Wing Volume % 40 No. Wings 5 Core Polymer Pebax 3533SN from
Atofina- elastomeric segmented polyetheresteramide- flex modulus
2800 psi (19,300 Pascals) Atofina address: Core Volume % 60 Draw
Ratio 4x (based on drow roll speed) % Face Plate Relaxation 20%
(based on winder speed) Relaxation jet steam pressure system 3 psi
% after boil-off stretch 95 % absolute shrinkage after BO 21 %
recovery after BO 90
Raw Materials Sourcing
[0126] The second yarn was a crimp free nylon 66 multi-filament
yarn of 40 denier (44 dtex) and 34 filaments spun and wound-up as
yarn package as commercially prepared b y E. I. DuPont de Nemours
and Co. Nylon Apparel Division. (see 120 in FIG. 1.)
Hetero-composite--Composite Yarn Preparation
[0127] The monofilament biconstituent yarn was air mingled with the
40-34 nylon companion yarn using a Hema-jet (Heberlein Type 311
available from Frank and Thomas, Greenvilee, S.C.) air entangling
jet (110) shown in FIG. 2. Care was taken to feed the biconstituent
monofilament yarn to the entangling jet as a flat hard yarn at low
even tension such that no spirally of the wings around the core of
the biconstituent filaments occurred during the air entangling
process. An entangling speed of 100 yards/minute (91 meters/minute)
was used and the resutling composite yarn was wound-up as package
130 in FIG. 2. The entangled yarn had a denier of 59, with the
biconstituent filament composing 32% weight of the final yarn. The
elastomer content (biconstituent core) represented 19% of the
weight of the final entangled yarn. After entangling the composite
yarn was wound onto a tube core. The composite yarn showed
essentually hard characteristics at this stage of processing, with
no unusual stretch or recovery properties.
Fabric Sample
[0128] A circular knit single feed length of jersey stitch tubing
fabric was fabricated using a Lawson circular tube knitting
machine. Tubes were knit in three different stitch densities to
check the degree of stretch and recovery imparted in the finished
fabric from the above yarn before and after dyeing and finishing.
The jersey knit tubes were dyed with standard nylon dyes at the
boil (100.degree. C.) for 30 minutes, and dried in a tray oven at
95.degree. C.
Fabric Sample Testing
[0129] The stretch and recovery properties of the circular knit
fabrics from the entangled yarns were evaluated and the results are
shown in Table 1 according to the following definitions:
[0130] Layout Length*Greige (LLG) and Layout Width* Greige (LWG)
are the measured length and width of a fabric tube section laid
flat on a table in the unstress state.
[0131] Relaxed Length*Finished RLF) is similarly a measure of the
length and width of the finished fabric tube section laid flat on a
table in the unstress state.
[0132] Stretched Length*Greige (SLG) is measured by folding the
fabric in half width-wise, and then stretching the greige fabric to
the jamming point by hand against a rule and noting the length.
[0133] Stretched Length*Finished (SLF) is similarly measured by
folding the fabric in half width-wise, and then stretching the
finished fabric to the jamming point by hand against a rule and
noting the length.
[0134] Relaxed Length*2nd Cycle (RLF2) is the relaxed length
recovered after one stretch cycle.
2TABLE 1* *all lengths and widths are in inches (1 inch = 2.54 cm)
Lawson Knitter 7.5 15 20 Needle pull setting Layout Length* 12 12
12 Greige Layout Width* 3 3 3 Greige Stretched Length* 21 17 16.5
Greige Stretched Length* 18 14 13 Finished % Length* 14 18 21
Shrinkage Relaxed Length* 8.25 7 7.5 Finished % Fabric Stretch 118
100 73 Relaxed Length* 9.5 8 8 2.sup.nd cycle % Elastic 87 86 91
Recovery Fabric % Set 13 14 9 % Length* Shrinkage is = 100 * (SLG -
SLF)/SLG % Fabric Stretch = 100 * (SLF - RLF)/RLF % Elastic
Recovery = 100 * (SLF - RLF2)/(SLF - RLF) % Set = 100 * (RLF2 -
RLF)/(SLF - RLF)
Interpretation
[0135] The data indicate that knit fabrics with high percent
stretch and excellent elastic recovery properties can be prepared
by entangling a moderate percentage by weight (32% in the example)
of biconstituent filaments in composite with typical hard (low
stretch) multifilament yarns. High percent stretch (73-118%
depending on stitch density) and elastomeric recovery (85-93%)
properties were generated since the biconstituent filaments shrinks
dramatically, but retain much of their shrinkage as recoverable
stretch (after boil-off stretch). The biconstituent yarn component
of the composite yarn shows sufficient shrink force, that, even at
moderate biconstituent content, the companion yarns are crimped or
bulked in such a manner that good stretch and recovery properties
are retained in the finished fabric. The finished fabric shows a
uniform appearance and soft hand with a fabric bulk increased over
the greige fabric. The ability to create fabrics with good
stretchability and true elastic recovery, using flat,
non-stretchable, input yarns is seen as a unique method for
creating stretch/recovery fabrics.
Example 2
Air Textured Biconstituent Composite Yarn in Knit Application
[0136] Hetero-composite-yarn combinations according to the
invention were prepared by combining a feed yarn composed entirely
(2.a.) or partially (2.b.) of biconstituent fibers, and an effect
yarn containing no biconstituent fibers in an air texturing
process.
Raw Materials Sourcing
[0137] The polymer raw materials were the same as shown in Example
1. In example 2.a. the feed yarn consisted of 70 denier 10
filaments biconstituent yarn spun as shown below.
[0138] In example 2.b. the feed yarn consisted of a combination of
at 30 denier monofilament biconstituent feed simultaneous with a 70
denier 66 filament nylon Tactel* commercial yarn sold by E. I.
DuPont de Nemours and Co., Wilmington, Del. Properties of the 30
denier biconstituent monofil are shown below.
[0139] The effect yarn used in both example 2.a and 2.b. was also
70 denier 66 filament DuPont Tactel*.
3 Biconstituent Yarn Spinning Denier 70 30 #filaments 10 `1
Wing/core interpentration yes yes Feed Roll Speed (m/min) 420 420
Primary Finish none none Primary Finish % 0 0 Secondary Finish type
K-9349 K-9349 Secondary Finish % 4% 4% Wing Polymer Camacari N6
Camacari N6 Wing Volume % 40 40 No. Wings 5 5 Core Polymer Pebax
3533SN Pebax 3533SN Core Volume % 60 60 Draw Ratio 4 4 % Face Plate
Relaxation 20 20 Relaxation jet steam pressure system 3 psi 3 psi %
after boil-off stretch 95 96.6 % absolute shrinkage after BO 21
20.5 % recovery after BO 90 92.8
Hetero-Composite--Yarn Preparation
[0140] To achieve an air texturing the effect yarn was forwarded
faster, i.e., slightly overfed to the texturing apparatus versus
the feed yarn. The air texturing jet was a Hema-jet (Heberlein Type
311 available from Frank and Thomas, Greenvilee, S.C.) air jet
(110) shown in FIG. 2. An air jet textured composite yarn was
created using a core yarn feed rate of 338 meters/minute, an effect
yarn feed rate of 391 meters/minute, an air pressure of 125 psi,
and a wind up speed of 312 meters/minute. Two different composite
yarns were processed as summarized in Table 2.
4TABLE 2 Feed Yarn Effect Yarn Composite Yarn 2a. 70 den.
(77dtex)-10 fil. 70 den. (77dtex)- consisted of a multifil Lot
67080 7207-44A 66 fil. biconstituent feed yarn and a multifil
homopolymer effect yarn Composite Yarn 2b. 30-1 & 70 den.
(77dtex)- 70 den. (77dtex)- jconsisted of a 66 fil.
(hetero-composite- 66 fil. biconstituent monofil and yarn)
homopolymer multifil are feed together as feed yarns; the effect
yarn was a multifil homopolymer nylon yarn
Fabric Sample
[0141] A single feed Lawson circular knitting machine was used to
fabricate knit fabric tubes in a jersey stitch configuration at
three stitch densities. The circular knit tubing was acid dyed with
nylon dyes at the boil for 30 minutes.
Fabric Sample Testing
[0142] The shrinkage, stretch, and recovery properties of the
circular knit fabrics from the co-textured yarns were evaluated
before and after finishing and the results are shown in. Table
3.
5TABLE 3 Yarn 2a. XD MD XD MD hand XD Hand Lawson MD Length XD
width MD hand % after Hand % % stretch Stitch Length after width
after % stretch boil-off stretch after Dial# Griege BO Greige BO
Griege stretch Griege boil-off 7.5 10 5.75 3.25 2.62 40% 80% 125%
125% 12 10 5.12 3.5 2.75 30% 90% 178% 115% 20 10 4.5 4.0 3.0 35%
120% 200% 150% Yarn 2b. MD XD MD hand XD Lawson MD Length XD width
MD hand stretch Hand XD Hand Stitch Length after width after
stretch after boil- stretch after Dial# Griege BO Greige BO Griege
off Griege boil-off 20 26.25 15.87 4.5 3.62 40% 90% 160% 125% MD* =
"LAWSON tube knitting "MACHINE DIRECTION" XD* = "LAWSON tube
knitting "CROSS MACHINE (perpendicular) DIRECTION"
Interpretation
[0143] The data indicate that knit elastic fabrics with high
stretch and excellent elastic recovery properties can be be
generated by co air texturing a moderatge weight percentage of
biconstituent filaments in composite with typical hard (low
stretch) multifilament yarns. High percent stretch (see table) and
elastomeric recovery properties are generated in view of the fact
that the initial texturing of the yarn was accomplished in the hard
yarn state. The biconstituent yarn component of the composite yarn
shows sufficient shrink force, that, even at moderate biconstituent
content, the companion yarns are bulked in such a manner that good
stretch and recovery properties are retained in the finished
fabric. The finished fabric was noted to show a uniform appearance
and a soft cotton-like hand with a fabric bulk increased over the
greige fabric. The ability to create fabrics with good
stretchability and true elastic recovery, using flat,
non-stretchable, input yarns is seen as a unique method for
creating stretch/recovery fabrics.
Example 3
Air Jet Textured Biconstituent Composite Yarn in Woven
Application
Raw Materials Sourcing
[0144] The raw materials and supply yarns were those used as in
example 2.a.
6 Feed Yarn Effect Yarn A. 70-10 Biconstituent 70-66 nylon
Biconstituent Yarn Spinning
[0145] The biconstituent yarn was spun at the following
conditions:
7 Denier 70 #filaments 10 Wing/core interpentration none Feed Roll
Speed (m/min) 420 Primary Finish none Primary Finish % 0 Secondary
Finish type K-9349 Secondary Finish % 4% Wing Polymer Camacari N6
Wing Volume % 40 No. Wings 5 Core Polymer Pebax 3533SN Core Volume
% 60 Draw Ratio 4 % Face Plate Relaxation 20 Relaxation jet steam
pressure system 3 psi % stretch after boil-off 100 % absolute
shrinkage after BO 20 % recovery after BO 90
Hetero-Composite--Yarn Preparation
[0146] A hetero-composite-air-textured yarn was created by
combining two yarns, as feed and effect yarns, in an air jet
texturing process as in Example 2A.
Fabric Sample
[0147] A fabric was woven on a shuttle loom using a plain weave
construction from the composite yarn of the example. The woven
fabric construction was based on a 200 denier 34 filament Tactel*
nylon (yarn available form E. I. DuPont de Nemours and Company) as
the warp fiber with 60 ends per inch. The co-air jet texture
composite yarn was used as the weft or fill fiber. The greige
fabric width was 62.5 inches. The fabric was finished with a
relaxed scour at 160 F, a second relaxed scour at 180 F, and dyed
at the boil using standard acid dyes, then air dried without heat
setting. The width of the fabric after relaxing, dyeing, and air
drying was 50 inches.
Fabric Sample Testing
[0148] The fabric were observed to be non-bulky, smooth, and
wrinkle-free with only air drying, and showed good stretch and
recovery, and excellent hard fiber hand and aesthetics. The relaxed
finished fabric showed the following characteristics:
[0149] Basis weight: 3.5 oz/sq yd or 119 gr/m.sup.2
[0150] Thickness: 10.4 mils (0.0104 inches) (0.026 centimeters)
[0151] Fill Count: 70
[0152] Warp Count: 85
[0153] A 5 cm width.times.10 cm length of fabric was evaluated for
% stretch and recovery in the weft. Using the method of Example 1.
the fabric stretched 28% in the weft direction, and showed
recovering after stretching of >85%.
Interpretation
[0154] The data indicated that the biconstituent composite yarns of
the invention are suitable for fabricating weft woven fabrics with
useful stretch and recovery properties.
Example 4
Biconstituent Composite Staple Yarn
Biconstituent Yarn Spinning
[0155] A biconstituent fibers with the following properties was
spun:
8 Denier 30 #filaments 1 Wing/core interpentration none Feed Roll
Speed (m/min) 420 Primary Finish none Primary Finish % 0 Secondary
Finish type K-9349 Secondary Finish % 4% Wing Polymer Camacari N6
Wing Volume % 40 No. Wings 5 Core Polymer Pebax 3533SN Core Volume
% 60 Draw Ratio 4 % Face Plate Relaxation 20 Relaxation jet steam
pressure system 3 psi % stretch after BO 96.6 % absolute shrinkage
after BO 20.5 % recovery after BO 92.8
Hetero-Composite--Yarn Preparation
[0156] In order to demonstrate the potential of latent stretch
yarns in staple processing the follow experiment was conducted: Two
lots of staple fiber, a) a companion staple fiber consisting of 3
dpf 1.5 inch cut length nylon crimped staple yarn used in
commercial staple processing and available from E. I. DuPont de
Nemours and Company, and b) the 30 denier monofilament
biconstituent fiber described above cut to 4 inch length staple,
were first hand carded separately to partially align the staple.
The two staples were then hand blended in 50/50 weight proportion,
and further hand carded to create a hand spinnable card sliver. The
sliver mix was than hand twisted to form a yarn. Further, two
length of the yarn were hand plied to form a two-ply yarn of 15,100
denier.
Yarn Sample Testing
[0157] To test the latent stretch potential of the staple yarn,
untreated and boiled-off samples of the yarn were compared for
stretch properties:
9 Stretch Denier % Stretch % Recovery from Untreated Yarn 15100 12%
95% Boiled Sample 22700 51% 99%
Interpretation
[0158] The data indicate that biconstituent cut staple fibers can
be blended with typical commercial staple fiber to form composite
staple yarns which show greatly enhanced stretch and recovery
properties after hot wet finishing. The blending is accomplished
with the biconstituent in the flat or unactiviated state. The
biconstituent staple filaments show sufficient shrinkage force that
companion staple filaments can be bulked or bent as the
biconstituent filaments shrink, resulting excellent elastic
recovery in the final staple yarn after hot wet processing.
Example 5
Biconstituent Composite Staple Yarn, Woven, and Knit Fabric
Biconstituent Yarn Spinning
[0159] A biconstituent yarn spun according to the process of
Example 1:
10 Wing polymer N6 3.14 IV Camacari Core polymer Pebax* 3533SN
supplied by Atofina Wing/Core ratio 40/60 No. of wings/filament 5
Denier total as spun 20 Number of filaments 1 Geometry keylock Draw
Ratio 3.5x Feed Roll Speed 500 ypm feed roll Relaxation System none
% Relaxation 0% Finish Type K-9349 FOY 4%
[0160] Tensile properties of the yarn were are follows:
11 Tenacity 2.4 gpd Elongation to break 28.8% Modulus 8.1 gpd
[0161] Skein tests revealed the following properties.
12 % stretch after boil off 99% % retention after boil off 91% %
shrinkage after boil off 25%
Hetero-Composite--Yarn Preparation
Cutting
[0162] Continuous spun yarn was cut to either 3.0 inch or 1.5 inch
staple using standard cutting techniques. No heat was applied to
the yarn during the cutting process.
Pre-Shrinking of biconstituent Staple
[0163] In many cases it is advantageous to process the staple in
the as-spun (hard fiber) state, and then activate the shrinkage
during post-processing, such as a fabric boil-off, autoclave, or
fabric dyeing and finishing step.
[0164] In other cases it is advantageous to "pre-shrink" the
biconstituent staple prior to further carding, blending, or
processing steps. Various methods of pre-shrinking the
biconstituent were demonstrated:
[0165] Pre-shrink Method #1: 3 pounds of biconstituent 3 inch cut
length and 1.5 inch cut length staple was placed in a cloth bags
separately, and subsequently the bagged fiber was placed on an
autoclave and subjected to 240 F pressurized steam for 20 minutes.
The bagged fiber was then placed in a tumble dryer at 100 C for 30
minutes. After processing the fiber was observed to have shrunk to
close to half its original length, from either 3.0 inches to 1.5
inches, or from 1.5 inches to 0.75 inches in length. The fiber was
observed to have recoverable stretch (after boil-off stretch) of
about 95 to 105%. To test opening and processing of the autoclave
prepared staple fiber, some of the staple was further run though a
Spinlab RotorRing Model #580 at settings: Feed: 7 rpm; Opener: 3800
rpm; Both 3" and 11/2" opened easily with no observable damage seen
under a microscope.
[0166] Pre-shrink Method #2: 3 pounds of biconstituent 3 inch cut
length and 1.5 inch cut length staple were placed in cloth bags
separately, and subsequently the bagged fiber was placed in a Cook
washer. Steam was used to bring the temperature of the water to 200
F, and the bags were agitated for 10 minutes. The wet bags of fiber
were then dewatered in an extractor, and placed in a tumble dryer
at 170 F for 5 minutes. On opening the bags the fiber was found to
open easily and suitable for further staple fiber blending
processes. After processing the fiber was observed to have shrunk
to close to half its original length, from either 3.0 inches to
about 1.5 inches, or from 1.5 inches to about 0.75 inches in
length.
Carding, Slivering, and Cotton Spinning
[0167] 3 pounds of 20 denier biconstituent fiber (as-spun in the
pre-activated state) was cut into staple. The fibers were blended
with cotton at Hamby Textile Industries such that the final blend
was 25% biconstituent and 75% cotton staple, and then carded,
drawn, roved, and ring spun at normal twist levels on commercial
equipment in the normal manner. An intimately blended 25/75
biconstituent/cotton ring spun yarn was produced with a 8/1 cotton
count.
Boil Off and Skein Data
[0168] 5000 denier skeins were made from this yarn to test for
shrinkage, stretch, and recovery. On boil-off the yarns were
observed to shrink significantly, and almost all of the shrinkage
was retained as recoverable stretch (after boil-off stretch). Using
a 0.2 gm per denier weight to extend. the skein, the following
values were observed after boil-off:
[0169] % shrinkage: 7.19%;
[0170] Stretch: 41.8%;
[0171] Recovery after Stretching: 75.3%
Interpretation
[0172] The data indicate that biconstituent cut staple fibers can
be blended with typical commercial staple fiber to form composite
staple yarns which show greatly enhanced stretch and recovery
properties after hot wet finishing. Further the examples below show
that knit, woven, and nonwoven fabrics with useful stretch and
elastic recovery properties can be made from yarns composed of at
least a portion of biconstituent staple fibers.
Example 5A
Woven Fabric
[0173] A hand woven sample was created on a frame using the above
yarn in both the weft (12 ends per inch) and the warp direction (13
ends per inch). 10 cm.times.10-cm marks were made the on fabric in
the pre-boil-off state. The fabric was then boiled off and the %
shrinkage and % stretch measured with the following result:
13 (cm) Marked ABO Stretched After 30 sec. Shrinkage Stretch WARP
10 5 8.5 5.5 50.0% 70.0% FILL 10 6 9.5 7 40.0% 58.3%
Example 5B
Knit Fabric
[0174] A Lawson knit tube of the high twist yarn, (ATS004) was knit
single end from the blend yarn before boil-off using a dial setting
of 5 and a 36-64 cylinder. The knit tube was boiled off by placing
in room temperature water and raising the temperature to
100.degree. C., holding at a strong boil for 10 minutes; then the
sample was flushed with cool tap water and dewatered using an
extractor; finally the fabric was tray dried for 30 minutes at 165
F. The fabric was marked in the greige, and the following absolute
shrinkage and recoverable stretch values were measured in the final
fabric:
[0175] J-120/Cotton Lawson Tubing
14 Marked After 30 (inches) ABO Stretched seconds Shrinkage
Recovery MD10 7.5 11.5 8 25% 53.3% 94% XD3 2.52 4.125 3.2 16% 63.7%
79%
Example 6
"Seamless" Circular Knit Fabrics
[0176] Two biconstituent yarns (5a and 5b) were spun as in previous
examples, a monofilament yarn and a five filament yarn, with the
apparatus of FIG. 4. Each filament of each yarn had 5 symmetric
wing portions from a nylon 6 polymer (CAMACARI) and containing 5%
by weight nylon 12 (RISLAN). The core was prepared with a PEBAX.TM.
3533SN core polymer. The core was 55% by volume of the total
filament cross section. The wing portions were interpenetrated
("keylocked") to the core portion. The biconstituent monofilament
was 25 denier, as spun, was spun at 500 meters per minute feed roll
speed using a 4% by weight primary fiber finish and 7% package
finish on the monofilament. The monofilament was relaxed by 20%
prior to wind-up with the aid of a steam treatment using 3 pound
per square inch steam pressure. The total draw ratio was
4.times..
[0177] The five filament yarn had a total denier of 34, and was
similarly produced in all respects except that the speed roll feed
was 420 meters per minute, and no primary finish was used.
[0178] The % stretch after boil off, % shrinkage after boil-off,
and % recovery from stretch after boil-off are indicated in the
table below:
15 Yarn a Yarn b Denier as spun 34 25 #filaments 5 1 Wing/core
interpentration yes yes Feed Roll Speed (m/min) 500 420 Primary
Finish NY-102 none Primary Finish % 4% 0 Secondary Finish type
K-9349 K-9349 Secondary Finish % 7% 7% Wing Polymer Camacari N6
Camacari N6 Wing Polymer Additive 5% Rilsan 5% Rilsan Wing Volume %
45 45 No. Wings 5 5 Core Polymer Pebax 3533SN Pebax 3533SN Core
Volume % 55 55 Draw Ratio 4 4 % Face Plate Relaxation 20 20
Relaxation jet steam pressuresystem 3 psi 3 psi % Stretch after BO
92 98 % Shrinkage after BO 21 19 % Recovery after BO 90 98
[0179] The 25 denier monofilament yarn 5a. and 34 denier
five-filament yarn 5b were fabricated into seamless circular knit
garment tubes using a SANTONI Corp. (Model SM-8 TOP) machine. Four
monofilament and four five-filament yarns feeds were fed in a
standard stitch pattern where the monofil yarn was used as a float
yarn to create a typical patterning effect for a panty garment.
Standard Memminger IRO tensioners were used to control yarn feed
tension. The fabric construction was a light weight sheer fabric of
approximately 95 grams/square meter. The SM-8 machine was set to
knit tube samples with a griege layout width of 15.5 inches, and a
layout length of 7.5 inches. The griege seamless tubes were
autoclaved boarded at 220 F for 5 minutes on a cylindrical porous
metal tube form 8.5 inches in diameter. The garment tubes were
observed to shrink to match the cylindrical diameter of the form
during autoclave steam treatment. The post autoclave boarded tube
dimensions were 13.5 in layout width and 7.5 inches in layout
length The final garment tube was observed to be uniform,
non-picky, and suitable for seamless garment applications such as
women's panties. The following hand stretch properties were
measured:
16 Greige Autoclave Boarded Width % Stretch 70% 85% Width Stretch %
Recovery 90% 95% Length % Stretch 79% 88% Length Stretch % Recovery
86% 95% Garment Power Minimal Much Higher
[0180] Those skilled in the art, having the benefit of the
teachings of the present invention as hereinabove set forth, can
effect numerous modifications thereto. These modifications are to
be construed as being encompassed within the scope of the present
invention as set forth in the appended claims.
* * * * *