FIELD OF THE INVENTION
[0001] This invention relates to woven fabrics, particularly woven fabrics comprising polyester
bicomponent filaments of poly(ethylene terephthalate) and poly(trimethylene terephthalate)
oriented in the warp direction of the woven fabric.
DESCRIPTION OF BACKGROUND ART
SUMMARY OF THE INVENTION
[0003] The present invention relates to a warp-stretch woven fabric of a plain, twill, or
satin construction. The woven fabric has weft yarns and warp yarns, and from about
15 to about 55 weight percent of the warp yarns are polyester bicomponent continuous
filaments comprising poly(ethylene terephthalate) and poly(trimethylene terephthalate).
The polyester bicomponent warp yarns have an after-heat-set crimp contraction value
preferably of about 20% to about 80%.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0004] It has now been found that warp-stretch woven fabrics can be prepared with unexpectedly
high stretch and recovery properties despite comprising comparatively low levels of
certain polyester bicomponent yarns.
[0005] As used herein, "polyester bicomponent filament" means a continuous filament comprising
a pair of polyesters intimately adhered to each other along the length of the filament,
so that the filament cross-section is for example a side-by-side, eccentric sheath-core
or other suitable cross-section from which useful crimp can be developed. "Yarn" means
a plurality of continuous filaments. "Pick-and-pick" means a woven construction in
which a polyester bicomponent filament weft yarn ("first yarn") and a ("second") weft
yarn are in alternating picks of the fabric. "Co-insertion" means a woven construction
in which a polyester bicomponent filament yarn ("first yarn") and a ("second") weft
yarn have been woven as one, in the same pick. "Woven separately" means the yarns
are separate from each other within the finished fabric, without having been twisted
or entangled together before being woven; herein "woven separately" does not preclude
weaving collections of substantially similar filaments (optionally interlaced with
each other) or weaving into a co-insertion construction.
[0006] The fabric of the invention is a warp-stretch woven selected from the group consisting
of plain, twill, and satin constructions. The warp-stretch woven has weft yarns and
warp yarns, wherein from about 15 to about 55 weight percent (preferably about 22
to about 33 weight percent) of the warp yarns are polyester bicomponent continuous
filaments comprising poly(ethylene terephthalate) and poly(trimethylene terephthalate).
The other warp yarns can be, for example, spun staple yarns, such as cotton, wool,
or linen; they can also be of monocomponent poly(ethylene terephthalate) fibers, monocomponent
poly(trimethylene terephthalate) fibers, polycaprolactam fibers, poly(hexamethylene
adipamide) fibers, acrylic fibers, modacrylic fibers, acetate fibers, rayon fibers,
and combinations thereof.
[0007] The weft yarns can be the same as, or different from, the warp yarns. The fabric
can be warp-stretch only, or it can be bi-stretch, in which useful stretch and recovery
properties are exhibited in both the warp and weft directions; such weft-stretch can
be provided by polyester bicomponent filament yarns, spandex, melt-spun elastomer,
and the like. When the weft yarns comprise polyester bicomponent filament ("first")
yarns, they can be present with a second yarn (optionally a spun staple yarn), for
example, in a pick-and-pick or co-insertion construction.
[0008] The bicomponent filament yarns can be present from about 13 to about 28 weight percent
(preferably about 13 to about 19 weight percent), based on total fabric weight when
none of the polyester bicomponent filaments are present in the weft (i.e., when the
polyester bicomponent filaments are only present in the warp).
[0009] The polyester bicomponent filaments comprise poly(ethylene terephthalate) and poly(trimethylene
terephthalate) in a weight ratio of about 30/70 to about 70/30, and have an after-heat-set
crimp contraction value from about 20% to about 80%, preferably about 30% to about
60%. Various comonomers can be incorporated into the polyesters of the bicomponent
filament in minor amounts, provided such comonomers do not have an adverse effect
on the amount of fiber crimp, and if the benefits of the invention are not deleteriously
affected. Examples include linear, cyclic, and branched aliphatic dicarboxylic acids
(and their diesters) having 4-12 carbon atoms; aromatic dicarboxylic acids (and their
esters) having 8-12 carbon atoms (for example isophthalic acid, 2,6-naphthalenedicarboxylic
acid, and 5-sodium-sulfolsophthalic acid); and linear, cyclic, and branched aliphatic
diols having 3-8 carbon atoms (for example 1,3-propane diol, 1,2-propanediol, 1,4-butanediol,
3-methyl-1,5-pentanedlol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propanediol,
and 1,4-cyclohexanediol). lsophthalic acid, pentanedioic acid, 5-sodium-sulfolsophthalic
acid, hexanedioic acid, 1,3-propane diol, and 1,4-butanediol are preferred. The polyesters
can also have incorporated therein additives, such as titanium dioxide.
[0010] The linear density of the polyester bicomponent filament yarn of which the fabric
of the invention is comprised can range from about 70 denier to about 900 denier (78
dtex to 1000 dtex).
[0011] It is preferred that the polyester bicomponent filament yarns not be twisted or entangled
combinations of bicomponent filaments with other, for example, monocomponent or staple,
fibers. In other words, it is preferred that the bicomponent filament yarns be woven
separately from the other yarns in the fabric in order to avoid the expense of an
additional step, to obtain high stretch and recovery properties, and to give high
fabric surface smoothness.
[0012] It is further preferred that less than about 3 wt% of a resin or similar material
be in or affixed to the fabric, because such resin treatment can add expense, and
the benefits of the invention are achieved without incurring this expense. Another
benefit of the invention is that the polyesters in the bicomponent filaments need
not be partially removed from the fabric by chemical means, for example, by application
of a chemical treatment such as a highly alkaline solution. While such resin and chemical
treatments might still be used in conjunction with the invention, we believe that
stretch and recovery properties of the woven fabric may be compromised, and thus prefer
to eliminate such added steps.
[0013] The fabric of the invention can be of plain, twill, or satin construction. Examples
of useful twill constructions include regular twills (for example, 2/1, 1/2, 1/3,
and 2/2 twills), modified twills (in which additional lifts have been added to the
weaving plan), herringbone, and pointed twills. Examples of useful satin constructions
include 5-end (for example 1/5 and 2/5).and 8-end (for example 3/8) weaves.
[0014] Loom types that can be used to make the woven fabrics of the invention include air-jet
looms, shuttle looms, water-jet looms, rapier looms, and gripper (projectile) looms.
[0015] Before being tested, fabrics and fibers were conditioned for 16 hours at 21°C +/-
1°C and 65% +/- 2% relative humidity.
[0016] After-heat-set contraction values were measured as follows. A sample of the bicomponent
polyester filament to be used was formed into a skein of 5000 +/-5 total denier (5550
dtex) with a skein reel at a tension of about 0.1 gpd (0.09 dN/tex). The skein was
conditioned at 70 +/- 2°F (21 +/- 1°C) and 65 +/- 2% relative humidity for a minimum
of 16 hours. The skein was hung substantially vertically from a stand, a 1.5 mg/den
(1.35 mg/dtex) weight (e.g. 7.5 g for a 5550 dtex skein) was hung on the bottom of
the skein, the weighted skein was allowed to come to an equilibrium length, and the
length of the skein was measured to within 1 mm and recorded as "C
b". The 1.35 mg/dtex weight was left on the skein for the duration of the test. Next,
a 500 g weight (100mg/d; 90mg/dtex) was hung from the bottom of the skein, and the
length of the skein was measured to within 1 mm and recorded as "L
b". Crimp contraction value (percent) (before heat-setting, as described below for
this test), "CC
b", was calculated according to the formula

The 500 g weight was removed and the skein was then hung on a rack and heat-set, with
the 1.35 mg/dtex weight still in place, in an oven for 5 minutes at about 225°F (107°C),
after which the rack and skein were removed from the oven and conditioned as above
for two hours. This step is designed to simulate commercial dry heat-setting, which
is one way to develop the final crimp in the bicomponent fiber. The length of the
skein was measured as above, and its length was recorded as "C
a". The 500 g weight was again hung from the skein, and the skein length was measured
as above and recorded as "L
a". The after heat-set crimp contraction value (%), "CC
a", was calculated according to the formula

[0017] In the Examples, unless otherwise noted, a Dornier rapier loom was used at 500 picks
per minute to make plain wovens with 55 picks per inch (22 picks/cm) and 1/3 twills
with 62 picks per inch (24 picks/cm) in the loomstate. The yarn of poly(ethylene terephthalate)
and poly(trimethylene terephthalate) ("bicomponent polyester yarn") was 150 denier
(167 dtex), 34 filament T-400 Elasterelle, available from DuPont Textiles and Interiors;
it was 40 wt% poly(ethylene terephthalate) and 60 wt% poly(trimethylene terephthalate)
and had an after-heat-set crimp contraction value of 47%. Before beaming, bicomponent
fiber yarns to be used in the warp were sized at 300 yards/minute (274 m/min) with
a poly(vinyl alcohol) size using a Suziki single end sizing machine in which the temperature
in the sizing bath was set at 107°F (42°C). The sized yarn was dried at 190°F (88°C)
for about 5 minutes. The fill yarn was ring-spun cotton of 30 cotton count. Poly(ethylene
terephthalate) yarn ("monocomponent polyester yarn"), when used, was a textured and
interlaced 150 denier (167 dtex), 50 filament yarn produced by Unifi, inc.
[0018] Each greige fabric was finished by passing it under low tension through hot water
three times at 160°F, 180°F and 202°F (71°C, 82°C, and 94°C, respectively); then de-sizing/pre-scouring
it with 6 wt% Synthazyme® (a starch-hydrolyzing enzyme from Dooley Chemicals LLC),
1 wt% Lubit® 64 (a nonionic lubricant from Sybron, Inc.), and 0.5 wt% Merpol® LFH
(a surfactant and registered trademark of E. I. du Pont de Nemours and Company) at
160°F (71°C) for 30 minutes, followed by addition of 0.5 wt% trisodium phosphate.
The fabric was then scoured with 1 wt% Lubit® 64 and 1 wt% Merpol® LFH at 110°F (43°C)
for 5 minutes, jet-dyed with a yellow disperse dye (and a yellow reactive dye when
cotton was present in the fabric) at 230°F (110°C) for 30 min at pH 5.2, and then
heat-set on a tenter frame at 340°F (171°C) for 40 sec while being underfed in the
warp direction. (Weight percents for finishing components are based on fabric weight.)
[0019] The Percent Available Stretch of the fabrics in the Examples was measured as follows.
Three 60 x 6.5 cm sample specimens were cut from each fabric. The long dimension corresponded
to the warp direction. Each specimen was unraveled equally on each side until it was
5 cm wide. One end of the fabric was folded to form a loop, and a seam was sewn across
the width to fix the loop. At 6.5 cm from the unlooped end of the fabric a first line
was drawn, and 50 cm away ("GL") from the first line, a second line was drawn. The
sample was conditioned for at least 16 hours at 20 +/- 2°C and 65 +/-2 % relative
humidity. The sample was then clamped at the first line and hung vertically. A 30
newton weight was hung from the loop, and the sample was exercised 3 times by alternately
allowing it to be stretched by the weight for 3 seconds and then supporting the weight
so the fabric was unloaded. The weight was re-applied, and the distance between the
lines ("ML") was recorded to the nearest millimeter. Percent Available Stretch was
calculated from Formula I,

and the results from the three specimens were averaged.
[0020] The Percent Recovery of the fabrics in the Examples was calculated as 100% minus
Percent Fabric Growth (% Fabric Growth), which was measured as follows. Three new
specimens were prepared as described for the Available Stretch test, extended to 80%
of the previously determined Available Stretch, and held in the extended condition
for 30 minutes. They were then allowed to relax without restraint for 60 minutes,
and the length ("L
2") between the lines was again measured. Percent Fabric Growth was calculated from
Formula II,

and the results from the three specimens were averaged.
[0021] In describing warp yarn repeating patterns in the fabric constructions of the Examples,
"bi" means bicomponent and "mono" means monocomponent. The repeating patterns used
were those that were most uniform for the weight percent of bicomponent filament warp
yarns present. For example, when the bicomponent filament yarns were at a 50 weight
percent level, the repeating pattern was bi/mono/bi/mono rather than bi/bi/mono/mono,
and when the bicomponent filament yarns were present at a 33 weight percent level
in the warp, the repeating pattern was bi/mono/mono/bi/mono/mono rather than bi/bi/mono/mono/mono/mono.
Although using most uniform repeating patterns for obtaining high fabric uniformity
in surface appearance, stretch, and recovery, such patterns are not required.
[0022] Available Stretch ("Stretch") and "Recovery" properties of the fabrics made In the
Examples are presented in Tables I (plain wovens) and II (twills). For clarity, the
yarns used in the Examples had the same linear density, so that warp end percent is
equal to warp weight percent. In the Tables, "Bicomponent weight percent" is based
on total warp weight. "Stretch per bicomponent wt%" and "Recovery per bicomponent
wt%" refers to the relative amount of bicomponent polyester yarn in the warp only.
EXAMPLES
EXAMPLE 1
[0023] A plain woven fabric was made in which the warp had a 1:1 end ratio (50/50 weight
ratio) of bicomponent polyester yarn to monocomponent polyester yarn, arranged alternately
at 86 ends/inch (34 ends/cm) in the loom state. The fabric was 80 inches (203 cm)
wide wide on the loom and and 78 inches (198 cm) wide off the loom in the greige state.
After dyeing and finishing, the fabric had yarn densities of 100 ends/inch (39 ends/cm)
and 96 picks/inch (38 picks/cm), weighed 4.86 oz/yd
2 (165 g/m
2), and contained 28 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 2
[0024] A plain woven fabric was made in which the warp had a 1:2 end ratio (33/67 weight
ratio) of bicomponent polyester yarn to monocomponent polyester yarn, arranged in
a bi/mono/mono repeating pattern at 86 ends/inch (34 ends/cm) in the loom state. The
fabric was 80 inches (203 cm) wide wide on the loom and and 78 inches (198 cm) wide
off the loom in the greige state. After dyeing and finishing, the fabric had yarn
densities of 90 ends/in (35 ends/cm) and 97 picks/in (38 ends/in), weighed 4.49 oz/yd
2 (152 g/m
2), and contained 19 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 3
[0025] A plain woven fabric was made in which the warp had a 1:3 end ratio (25/75 weight
ratio) of bicomponent polyester yarn to monocomponent polyester yarn, arranged in
a bi/mono/mono/mono repeating pattern at 86 ends/inch (34 ends/cm) in the loom state.
The fabric was 80 inches (203 cm) wide on the loom and and 78 inches (198 cm) wide
off the loom in the greige state. After dyeing and finishing, the fabric had yarn
densities of 100 ends/in (39 ends/cm) and 95 picks/inch (37 picks/cm), weighed 4.55
oz/yd
2 (154 g/m
2), and contained 14 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 4
[0026] A twill fabric was made in which the warp had a 1:1 end ratio (50/50 weight ratio)
of bicomponent polyester yarn to monocomponent polyester yarn, arranged alternately
at 86 ends/inch (34 ends/cm) in the loom state. The fabric was 80 Inches (203 cm)
wide on the loom and 75 inches (190 cm) wide in the greige state. After dyeing and
finishing, the fabric had yarn densities of 104 ends/inch (41 ends/cm) and 88 picks/inch
(35 picks/cm), weighed 5.47 oz/yd
2 (185 g/m
2), and contained 27 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 5
[0027] A twill fabric was woven in which the warp had a 1:2 end ratio (33/67 weight ratio)
of bicomponent polyester yarn to monocomponent polyester yarn, arranged in a bi/mono/mono
repeating pattern at 86 ends/inch (34 ends/cm) in the loom state. The fabric was 80
inches (203 cm) wide on the loom and 75 inches (190 cm) wide in the greige state.
After dyeing and finishing, the fabric had yarn densities of 90 ends/inch (35 ends/cm)
and 92 picks/inch (36 picks/cm), weighed 4.92 oz/yd
2 (167 g/m
2), and contained 18 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 6
[0028] A twill fabric was made in which the warp had a 1:3 end ratio (25/75 weight ratio)
of bicomponent polyester yarn to monocomponent polyester yarn, arranged in a bi/mono/mono/mono
repeating pattern at 86 ends/inch (34 ends/cm) in the loom state. The fabric was 80
inches (203 cm) wide on the loom and 78 inches (198 cm) wide in the greige state.
After dyeing and finishing, the fabric had yarn densities of 100 ends/inch (39 ends/cm)
and 107 picks/inch (42 picks/cm), weighed 5.67 oz/yd
2 (192 g/m
2), and contained 13 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 7
[0029] A plain woven fabric was made in which the warp had a 1:1 end ratio (50/50 weight
ratio) of bicomponent polyester yarn to sized 30 cotton count ring-spun cotton, arranged
alternately at 86 ends/inch (34 ends/cm) in the loom state. The fabric was 80 inches
(203 cm) wide on the loom and 78 inches (198 cm) wide in the greige state. After dyeing
and finishing, the gray fabric had yarn densities of 88 ends/inch (35 ends/cm) and
98 picks/inch (39 picks/cm), weighed 4.78 oz/yd
2 (162 g/m
2), and contained 28 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 8
[0030] A twill fabric was made in which the warp had a 1:2 end ratio (33/67 weight ratio)
of bicomponent polyester yarn to monocomponent polyester yarn, arranged in a bi/mono/mono
repeating pattern at 86 ends/inch (34 ends/cm) in the loom state. The weft yarn was
monocomponent polyester yarn. The fabric was 80 inches (203 cm) wide on the loom and
75 inches (190 cm) wide in the greige state. After dyeing and finishing, the fabric
had yarn densities of 120 ends/inch (47 ends/cm) and 90 picks/inch (35 picks/cm),
weighed 5.85 oz/yd
2 (198 g/m
2), and contained 18 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 9
[0031] A plain woven fabric was made in which the warp had a 1:1 end ratio (50/50 weight
ratio) of bicomponent polyester yarn to monocomponent polyester yarn, arranged alternately
at 86 ends/inch (34 ends/cm) in the loom state. The weft yarn was entirely of bicomponent
polyester yarn. The fabric was 80 inches (203 cm) wide on the loom and 76 inches (193
cm) wide in the greige state. After dyeing and finishing, the fabric had available
stretch in the warp and weft directions of 26% and 25%, respectively, and yarn densities
of 112 ends/inch (44 ends/cm) and 95 picks/inch (37 picks/cm). The weight of the fabric
was 5.8 oz/yd
2 (197 g/m
2), and it contained 72 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 10
[0032] A twill fabric was woven in which the warp had a 1:1 end ratio (50/50 weight ratio)
of bicomponent polyester yarn to monocomponent polyester yarn, arranged alternately
at 86 ends/inch (34 ends/cm) in the loom state. The weft yarns were bicomponent polyester
yarn and 30 cotton count ring-spun cotton, woven pick-and-pick. The fabric was 80
inches (203 cm) wide on the loom and 76 inches (193 cm) wide in the greige state.
After dyeing and finishing, the fabric had available stretch of 50% and 17% In the
warp and weft directions, respectively, and yarn densities of 115 ends/inch (45 ends/cm)
and 90 picks/inch (35 picks/cm). The fabric weighed 6.44 oz/yd
2 (218 g/m
2), and it contained 50 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 11
[0033] A plain woven fabric was made in which the warp had a 1:1 end ratio (50/50 weight
ratio) of bicomponent polyester yarn to monocomponent polyester yarn, arranged alternately
at 86 ends/inch (34 ends/cm) in the loom state. The weft yarns were bicomponent polyester
yarn and monocomponent polyester yarn, woven pick-and-pick. The fabric was 80 inches
(203 cm) wide on the loom and 75 inches (190 cm) wide in the greige state. After dyeing
and finishing, the fabric had 31% and 18% available stretch in the warp and weft directions,
respectively, and yarn densities of 94 ends/inch (37 ends/cm) and 102 picks/inch (40
picks/cm). The fabric weighed 5.64 oz/yd
2 (191 g/m
2), and it contained 50 wt% bicomponent polyester yarn, based on total fabric weight.
EXAMPLE 12 (COMPARISON)
[0034] A plain woven fabric was made in which the warp was entirely bicomponent polyester
yarn; that is, the end ratio was 1:0. The weft yarn was 30cc ring-spun cotton. A Ruti
air-jet loom was used at 500 picks per minute. On the loom, the yarn counts were 70
ends/inch (28 ends/cm) and 50 picks/inch (20 picks/cm). The fabric was 67 inches (170
cm) wide on the loom and 65 inches (165 cm) in the greige state. After dyeing and
finishing, the fabric had a weight of 3.47 oz/yd
2 (118 g/m
2) and yarn densities of 74 ends/inch (29 ends/cm) and 72 picks/inch (28 picks/cm),
and it contained 54 wt% bicomponent polyester yarn, based on total fabric weight.
TABLE I
Example |
End ratio |
Warp Bicomponent Weight% |
Fabric Stretch, % |
Stretch per warp bicomponent wt% |
Fabric Recovery, % |
Recovery per warp bicomponent wt% |
1 |
1:1 |
50 |
34 |
0.7 |
98 |
2.0 |
2 |
1:2 |
33 |
23 |
0.7 |
98 |
3.0 |
3 |
1:3 |
25 |
25 |
1.0 |
99 |
4.0 |
7 |
1:1 |
50 |
36 |
0.7 |
Nm |
nm |
9 |
1:1 |
50 |
26 |
0.5 |
Nm |
nm |
11 |
1:1 |
50 |
31 |
0.6 |
Nm |
nm |
12 (Comp.) |
1:0 |
100 |
30 |
0.3 |
99 |
1.0 |
Table II
Example |
End ratio |
Warp Bicomponent Weight % |
Fabric Stretch, % |
Stretch per warp bicomponent wt% |
Fabric Recovery, % |
Recovery per warp bicomponent wt% |
4 |
1:1 |
50 |
43 |
0.9 |
97 |
1.9 |
10 |
1:1 |
50 |
50 |
1.0 |
Nm |
nm |
5 |
1:2 |
33 |
28 |
0.8 |
99 |
3.0 |
8 |
1:2 |
33 |
23 |
0.7 |
Nm |
nm |
6 |
1:3 |
25 |
27 |
1.1 |
98 |
3.9 |
[0035] The data in Tables I and II show that unexpectedly and disproportionately (compared
to their bicomponent filament yarn content) high stretch and recovery properties are
exhibited by the fabrics of the invention. The designation "nm" indicates a value
was "not measured".
- 1. A warp-stretch woven fabric selected from the group consisting of plain, twill
and satin construction, comprising:
a plurality of weft yarns and a plurality of warp yarns, wherein from about 15 to
about 55 weight percent of the warp yarns are polyester bicomponent continuous filaments
comprising poly(ethylene terephthalate) and poly(trimethylene torephthalate) and having
an after-heat-set crimp contraction value from about 20% to about 80%.
- 2. The fabric according to embodiment 1, wherein from about 22 to about 33 weight
percent of the warp yarns are polyester bicomponent continuous filaments.
- 3. The fabric according to embodiment 1, wherein the bicomponent continuous filament
warp yarns are woven separately from other warp yarns in the woven fabric construction.
- 4. The fabric according to embodiment 1, wherein the weft yarns comprise a first yarn
and a second yarn, and wherein the first yarn comprises bicomponent continuous filaments
of poly(ethylene terephthalate) and poly(trimethylene terephthalate).
- 5. The fabric of embodiment 4, wherein the weft has a construction selected from the
group consisting of pick-and-pick and co-insertion.
- 6. The fabric of embodiment 4, wherein the second yarn is a spun staple yarn.
- 7. The fabric of embodiment 1, wherein the fabric has a warp yarn repeating pattern
selected to be most uniform for the weight percent of polyester bicomponent filament
warp yarns present.
- 8. The fabric of embodiment 1, comprising from about 13 weight percent to about 28
weight percent polyester bicomponent yarns, based on total fabric weight, wherein
the bicomponent yarns are present only in the warp.
- 9. The fabric of embodiment 1, comprising from about 13 weight percent to about 19
weight percent polyester bicomponent yarns, based on total fabric weight.