U.S. patent application number 11/018003 was filed with the patent office on 2005-06-23 for dyed 2gt polyester-spandex circular-knit fabrics and method of making same.
Invention is credited to Chuang, Cheng-Yuan, Laycock, Graham, Leung, Raymond S.P..
Application Number | 20050132509 11/018003 |
Document ID | / |
Family ID | 32851059 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050132509 |
Kind Code |
A1 |
Chuang, Cheng-Yuan ; et
al. |
June 23, 2005 |
Dyed 2GT polyester-spandex circular-knit fabrics and method of
making same
Abstract
The invention includes a dyed knit, elastic fabric comprising
polyethylene terephthalate and spandex. The fabric has staining
grade numbers of 4.0 or higher, as measured by staining of
multifiber test fabrics in AATCC Test Method 61-1996-2A, and is
dyed with disperse dyes comprising azo or anthraquinone molecular
groups. The invention further includes a method for making the knit
fabric.
Inventors: |
Chuang, Cheng-Yuan;
(Panchiao, TW) ; Laycock, Graham; (Grangeford,
SG) ; Leung, Raymond S.P.; (Shatin, NT) |
Correspondence
Address: |
INVISTA NORTH AMERICA S.A.R.L.
THREE LITTLE FALLS CENTRE/1052
2801 CENTERVILLE ROAD
WILMINGTON
DE
19808
US
|
Family ID: |
32851059 |
Appl. No.: |
11/018003 |
Filed: |
December 21, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11018003 |
Dec 21, 2004 |
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PCT/US04/17364 |
Jun 1, 2004 |
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PCT/US04/17364 |
Jun 1, 2004 |
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10454746 |
Jun 2, 2003 |
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6776014 |
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Current U.S.
Class: |
8/444 |
Current CPC
Class: |
D10B 2403/0114 20130101;
Y10T 442/413 20150401; D04B 1/18 20130101; D10B 2331/10 20130101;
D10B 2201/02 20130101 |
Class at
Publication: |
008/444 |
International
Class: |
D06P 005/20 |
Claims
1. Knit elastic fabric with staining grade numbers of 4.0 or
higher, as measured by staining of multifiber test fabrics in AATCC
Test Method 61-1996-2A, said knit fabric comprising polyethylene
terephthalate and spandex, said knit fabric dyed with disperse dyes
comprising azo or anthraquinone molecular groups.
2. The knit fabric of claim 1, wherein the fabric has a basis
weight in the range from about 160 to about 330 g/m.sup.2, and an
elongation in the length direction of about 80% or more.
3. The knit fabric of claim 2, wherein the elongation in the length
direction ranges from about 80% to about 130%.
4. The knit fabric of claim 2, wherein the spandex content by
weight ranges from about 4% to about 15%, and the shrinkage of said
fabric after washing and drying at laundering conditions is about
3% or less in the fabric length and width directions.
5. The knit fabric of claim 1, wherein the fabric has a basis
weight in the range from about 160 to about 330 g/m.sup.2, and an
elongation in the length direction of about 80% or more.
6. The circular knit fabric of claim 5, wherein the elongation in
the length direction ranges from about 80% to about 130%.
7. The circular knit fabric of claim 5, wherein the spandex content
by weight ranges from about 4% to about 15%, and the shrinkage of
said fabric after washing and drying at laundering conditions is
about 3% or less in the fabric length and width directions.
8. A garment made from the dyed circular knit, single jersey
elastic fabric of claim 1.
9. A method for making dyed, circular-knit single-jersey elastic
fabric with staining grade numbers of 4.0 or higher, as measured by
staining of multifiber test fabrics in AATCC Method 61-1996-2A,
wherein the fabric is knit with hard yarn of polyethylene
terephthalate or blends thereof and with plated bare spandex yarn,
said method comprising: a) controlling the feed of the spandex yarn
in the knitting process so that the spandex yarn is drafted no more
than about 2.5.times. its original length; b) dyeing the fabric in
an aqueous dye liquor of azo- or anthraquinone-based disperse dyes
at temperatures below about 135 degrees Centigrade; c)
reduction-cleaning the fabric after dyeing to remove dye from the
surface of the fibers in the fabric; and d) drying the fabric in an
oven at oven temperature below about 130 degrees C.
10. The method of claim 9, wherein bare spandex yarns of decitex
ranging from about 17 to about 44 are plated in every course with
one or more spun or continuous filament yarns, or blends thereof,
of decitex ranging from about 55 to about 165, and wherein the knit
stitch length and the polyethylene terephthalate yarn decitex are
selected so that the knit cover factor ranges from about 1.1 to
about 1.6.
11. The method of claim 10, wherein the knit cover factor ranges
from about 1.2 to about 1.4 and the decitex per filament of the
polyethylene terephthalate fibers ranges from about 0.05 to about
3.5
12. The method of claim 10, wherein the fabric dyeing step
comprises contacting the fabric with dye in a jet dye machine and
the fabric drying step comprises drying the fabric in a tenter
oven.
13. The method of claim 12, wherein the temperature of the drying
oven ranges from about 120 to about 125 degrees C.
14. A dyed, circular-knit single-jersey elastic fabric with
staining grade numbers of 4.0 or higher as measured by staining of
multifiber test fabrics in AATCC Method 61-1996-2A, made by the
method of claim 11.
15. Dyed, circular-knit single-jersey elastic fabric with staining
grade numbers of 4.0 or higher as measured by staining of
multifiber test fabrics in AATCC Method 61-1996-2A, made by the
method of claim 11.
16. A garment made from the dyed circular knit, single jersey
elastic fabric of claim 14.
Description
FIELD OF THE INVENTION
[0001] This invention relates to 2GT polyester-spandex
circular-knit elastic fabrics which are dyed with disperse dyes.
This invention also relates to a method of knitting, dyeing and
finishing fabrics.
BACKGROUND OF THE INVENTION
[0002] Relatively small percentages of spandex fiber are frequently
added to knit fabrics of `hard` yarns, such as nylon, cotton,
acrylic, wool and 2GT polyester, for example, in order to provide
significant fabric stretch and recovery to the fabrics and the
garments made therefrom. Hard yarns are relatively inelastic, which
means that they can be stretched only very minor amounts without
permanent deformation. As used herein, "spandex" means a
manufactured fiber in which the fiber-forming substance is a
long-chain synthetic polymer comprised of at least 85% of a
segmented polyurethane. The polyurethane is prepared from a
polyether glycol, a mixture of diisocyanates, and a chain extender
and then melt-spun, dry-spun or wet-spun to form the spandex
fiber.
[0003] For fabrics that are knit on circular, or weft, knitting
machines the spandex is normally added as a bare yarn, without
covering, and is fed in parallel with the hard yarn to the knitting
needles. On its path from the feed package to the knit stitch, the
spandex is under tension and is typically stretched, or drafted,
2.5.times. or more its original length; for example, drafting of 40
denier spandex yarn is typically 3.5.times.. Subsequent to
knitting, the fabric is preset, scoured or cleaned, dyed, and then
heatset to provide a colored fabric of desired dimensions and
appearance. The method of dyeing and the types of dyes used depend
mostly on the type of hard yarn used in the fabric, e.g., 2GT
polyester, nylon, cotton, etc.
[0004] Fibers of polyethylene terephthalate (PET) polymer
(hereinafter referred to as "2GT polyester" in this Specification)
are hydrophobic and highly crystalline. Because the 2GT polyester
contains no chemically active groups that interact with
water-soluble dyes, the 2GT polyester can be dyed only with
disperse dyes. The disperse dye class is so named because these
dyes are almost insoluble in water and are used as finely divided
aqueous dispersions (ref. ATI). Dyeing of 2GT polyester fibers is
understood by many as a process wherein dye molecules penetrate
into the 2GT polyester and into the available spaces among the 2GT
polyester macromolecules. For the dye to penetrate the fiber to
sufficient depths, in sufficient amounts and in a reasonable amount
of time, the polymer structure must be `opened up` to allow more
efficient penetration of the dye molecules. If 2GT polyester is
dyed in an aqueous solution at atmospheric pressure at 100 degrees
C. or less, a `carrier` is normally required to help open the 2GT
polyester structure. A carrier is a chemical, such as
chlorobenzene, orthophenyl phenol, aromatic esters, and chlorinated
hydrocarbons, that adds cost to the process and also creates
environmental problems when disposing of the dye bath liquids that
contain the carriers. An alternative, which is most widely used, is
to heat the aqueous solution to about 130 degrees C. in a pressure
vessel for batch dyeing of the 2GT polyester-containing knit
fabric. Such higher temperatures are sufficient to open the 2GT
polyester fiber for efficient dyeing without the use of a carrier.
High-pressure, high-temperature dyeing of 2GT polyester-containing
knit fabric is almost always done now in equipment known as a jet
dyer, wherein a loop of tubular knit fabric is moved in and out of
the dye liquor by action of a venturi jet that uses the liquor (or
alternately air) to forward the fabric.
[0005] Regardless of the particular 2GT polyester-dyeing method
used, with or without carrier, it is well known that dyed 2GT
polyester typically has a `washfastness` problem wherein dye
molecules can migrate to the 2GT polyester fiber surface and stain
other fabrics and garments during clothes washing. The American
Association of Textile Chemists and Colorists (AATCC) has developed
standards to test the washfastness of dyed fabrics as measured by
the staining of multifiber fabric test samples (e.g., acetate,
cotton, polyamide, 2GT polyester, acrylic and wool) that are in the
wash with the fabric whose washfastness is being tested. The
individual fabric test samples are graded from 1 to 5, to indicate
how much each has been stained by the dyed fabric being tested; a
grade of 5 indicates no staining, wherein a grade of 1 indicates
very significant staining. It is quite usual for 2GT polyester-dyed
fabrics to stain companion polyamide fabrics, e.g., of nylon 6 and
nylon 66 fibers, to a rating of 2 to 3.
[0006] Over time, the industry has learned various means and ways
to reduce the 2GT polyester dye washfastness problem for specific
cases. The choice of dye, in terms of color, shade and molecular
structure, can result in more or less staining. Disperse dyes for
dyeing PET are almost all made from chromophores of azo and
anthraquinone, which have different structures and performance from
one another. Dyes of other chromophores have been developed, which
do give better washfastness performance, but these dyes are not in
broad commercial use. Some dyes, azo and anthraquinone disperse
dyes included, have more or less affinity for staining companion
fabrics in a wash. Also, there are dyes with relatively large
molecules and small molecules, and they are generally categorized
as high energy to low energy dyes, respectively, as determined by
the amount of energy to cause them to move into and out of the 2GT
polyester or to sublimate. High energy dyes are also known as
S-rated (or D) dyes by those in the trade. Middle energy dyes are
also known as SE-rated (or C) dyes by those in the trade. Low
energy dyes are also known as E-rated (or B) dyes by those in the
trade.
[0007] Dyes of different shades stain more or less, with dyes of
deep colors of red, black and blue being particularly susceptible
to poor washfastness. Various methods for cleaning surface dye from
fibers after dyeing have been developed, including reduction
clearing. In reduction clearing, the fabric with dyed fibers is
placed in a bath containing a reducing agent (e.g., hydrosulfite)
and a base (e.g., sodium hydroxide); under the reduction-clearing
process conditions, only the dye on the surface of the fibers is
removed.
[0008] It is also known that heat treating 2GT polyester fibers, in
order to reduce shrinkage or fix dimensions, also causes the
phenomenon of thermomigration, wherein dye molecules migrate to the
surface of the fiber and are then ready to stain other fabrics in
the wash. Heat treating at high temperatures such as 175-200
degrees C. and higher is very detrimental to washfastness of dyed
2GT polyester fibers, so that heat treating of 2GT polyester
fabrics is done before dyeing when possible. It is thus possible to
use a combination of process step sequences, conditions and
materials to mitigate dyed 2GT polyester washfastness for specific
cases and types and colors of fabrics.
[0009] When spandex and 2GT polyester fibers are circular knit into
elastic fabrics and subsequently dyed with an azo- or
anthraquinone-based disperse dye, the problems of washfastness are
worse, compared to washfastness of fabrics knit from 2GT polyester
alone. Both the 2GT polyester and spandex are subject to
thermomigration of dye molecules from the interior to the surface
of the fibers. Further, in cut and sew fabrics, the last step in
the circular-knit elastic fabric finishing process, after dyeing,
is to heatset the fabric in open width at its desired length and
width dimensions. This is necessary because the spandex, being
elastic and having a retractive force after being drafted in
knitting, will cause the final fabric to be too dense or have too
much elastic elongation for the garment end-use desired. The final
heatset step is necessary to achieve the final fabric desired
properties, such as basis weight, stretch elongation, edge curl and
appearance. To heatset the spandex at the desired open-width
dimensions typically requires dry heat at temperatures of 175 to
185 degrees C. These temperatures result in significant
thermomigration of the dye and poor fabric washfastness results as
measured by staining of other fabrics in the wash. Because of the
strong effect of heatsetting on 2GT polyester-spandex knit fabric
washfastness, there are no means to improve washfastness to stain
grading levels of 4 to 5, for such fabrics that are heatset as a
final step and are dyed with middle energy, SE-rated or high
energy, S-rated dye colors and dyeshades. As a result, the market
opportunities are limited for 2GT polyester-spandex knit fabrics,
and particularly for fabrics dyed into dark, rich colors. There is
long-standing need for such fabrics that are adequately washfast,
and for an economical method to make them.
[0010] U.S. Pat. No. 6,776,014 to Laycock, Leung and Singewald
teaches a spandex-containing fabric and method for making the same.
The method includes circular knitting with spandex at low draft and
controlling the finishing and drying temperatures below the spandex
heat set temperature.
SUMMARY OF THE INVENTION
[0011] The invention includes a dyed knit, elastic fabric
comprising polyethylene terephthalate and spandex. The fabric has
staining grade numbers of 4.0 or higher, as measured by staining of
multifiber test fabrics in AATCC Test Method 61-1996-2A, and is
dyed with disperse dyes comprising azo or anthraquinone molecular
groups. The invention further includes a method for making the knit
fabric.
[0012] An elastic knit fabric of the invention comprising 2GT
polyester and spandex, can exhibit good azo- and
anthraquinone-disperse dye washfastness and desirable physical
properties. The invention further includes a method for making the
knit fabric that avoids heat-setting the fabric under dry
conditions at elevated temperature as further described below.
[0013] The invention may include a circular-knit single-jersey
elastic fabric that may include bare spandex plated with yarns of
2GT polyester continuous filament, 2GT polyester staple or 2GT
polyester staple blends. The fabric can be dyed with azo or
anthraquinone disperse SE or S dyes, and the fabric may have an
improved washfastness rating versus conventional fabrics when
measured as staining nylon, cotton, 2GT polyester, wool, or acrylic
in an accelerated laundering test per AATCC Test Method 61-1996-2A.
The fabric can have a basis weight in the range of 160 to 330 g/m2,
and an elongation of 80% or more, for example from 80% to 130% in
the length (warp) direction. Further, said fabric can have a
spandex content by weight of 4% to 15% and a shrinkage after
washing and drying of about 3% or less, and for example less than
3% in both length and width direction.
[0014] The invention also may include a garment made from the
fabric described above. Such garments may be top-weight
garments.
[0015] The invention can include a method for knitting, dyeing and
finishing a knit elastic fabric comprising 2GT polyester and
spandex, without open-width dry heat setting after dyeing. For
example, the method may produce a single jersey circular knit
fabric. The spandex feed yarn can range from about 17 to about 44
dtex and the 2GT polyester yarn can range from about 55 to about
165 dtex, with the 2GT polyester dtex per filament ranging from
about 0.05 to about 3.5. The stitch length and 2GT polyester dtex
can be selected so that the knit cover factor ranges from about 1.1
to about 1.6, and for example from about 1.2 to about 1.4. During
knitting, the spandex yarn and 2GT polyester yarn may be plated in
every course and the draft of the spandex feed yarn may be
controlled so that the spandex yarn may be drafted no more than
about 2.times. or about 2.5.times. its original length, depending
on the embodiment of the method. In a first embodiment, the knit
fabric can be disperse dyed at atmospheric pressure at dye liquor
temperatures of about 100 degrees C. or less, typically with a
carrier, and the total spandex draft after knitting may be limited
to about 2.times.. In a second embodiment the knit fabric is
disperse dyed above atmospheric pressure at dye liquor temperatures
ranging from about 110 to about 135 degrees C., and the total
spandex draft after knitting is limited to about 2.5.times.. The
dye liquor may contain azo or anthraquinone disperse dyes.
Following dyeing, the fabric can be reduction-cleared and rinsed in
order to remove excess dye from the surface of the fibers, and can
then be air dried in open width in a tenter frame oven. The open
width fabric may be held at its natural width and length and heated
until dry. The air drying temperature can be a maximum of about 130
degrees C. or less, and can be for example from about 120 to about
125 degrees C. These drying temperatures are the maximum dry heat
temperatures that the fabric will experience in finishing after the
dyeing step.
[0016] The invention also may include the circular knit, elastic,
single jersey fabrics made according to the inventive method, and
garments constructed from such fabrics.
BRIEF DESCRIPTION OF THE FIGURES
[0017] FIG. 1 illustrates plated knit stitches comprising a hard
yarn and spandex.
[0018] FIG. 2 is a schematic diagram of a portion of a circular
knitting machine fed with a spandex feed and a hard yarn feed.
[0019] FIG. 3 illustrates a series of single jersey knit stitches
and highlights one stitch of stitch length "L".
[0020] FIG. 4 is a flow chart showing standard process steps for
knitting, dyeing and finishing 2GT polyester-spandex circular-knit,
elastic, single-knit jersey fabrics.
[0021] FIG. 5 is a flow chart showing the inventive process steps
for knitting, dyeing and finishing 2GT polyester-spandex
circular-knit, elastic, single-knit jersey fabrics.
[0022] While the invention will be described in connection with
embodiments below, it is to be understood that the invention is in
no way intended to be limited by such description. On the contrary,
it is intended to cover all alternatives, modifications and
equivalents as may be included within the true spirit and scope of
the invention as defined by the claims appended hereto.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Knit fabrics of the invention may include those fabrics of a
single-jersey stitch, with bare spandex plated in every course. The
term "Commercially-useful" as used herein refers to ranges of
physical properties (including fabric basis weight, washfastness,
elongation, stability and appearance) that can be associated with
apparel fabrics.
[0024] FIG. 4 shows a flow diagram of a process 40 for making,
dyeing and finishing circular knit fabrics of 2GT
polyester-spandex. Depending on the knitting machine, the circular
knit fabric will be knit into a tube, or cut into an open width
(sheet) at the exit of the machine. The spandex is highly drafted,
e.g., 3.5.times. for 44 dtex spandex, as it is plated into the knit
stitches with the hard yarn. If the fabric is in tubular form at
the exit of the knitting machine, the fabric is slit open 44 in a
separate step before being relaxed and preset in a tenter oven 46,
at temperatures typically at 190 degrees C., but typically for a
very short residence time of 45-60 seconds. The purpose of this
process step is to relax the spandex tension. Subsequent to
relaxation and preset, the open fabric is sewn back into a tubular
form 48 for multiple sequential operations in a jet-dye machine 50.
While there are many variations of design of jet dye machines, they
are all batch devices that circulate a tube of fabric, by means of
a venturi jet that uses bath liquid, continuously into and out of a
liquid bath of cleanser/bleach, or dye liquor, or caustic solution,
as the case may be in the process step being performed. For
cleaning, bleaching and reduction-clearing operations, the jet dye
machine is operated at atmospheric pressure and liquid temperatures
of 100 degrees C. or less. Some specific chemicals, processing
conditions and process residence times are given in the Examples.
For dyeing the 2GT polyester-spandex fabric, the jet-dye machine
may be loaded both with fabric and dye liquor, pressurized and
heated to about 130 degrees C., and then operated by circulating
the fabric through the dye liquor at specified process conditions
and residence time sequences. One variable of importance is the
liquor ratio, or the ratio of fabric weight to the weight of the
dye liquor in the jet-dye machine.
[0025] After the above cleaning, bleaching, dyeing, and
reduction-clearing operations, the fabric is removed from the jet
dyer and dewatered 52 in a centrifuge or in squeeze rollers, for
example. The tubular fabric is then un-sewn (de-tacked) 54 and
opened once again into an open-width (sheet) fabric.
[0026] The dewatered, open-width 2GT polyester-spandex knit fabric
is then processed in a tenter frame oven, to heat set the fabric
into desired and stable length and width dimensions. The tenter
frame stretches the fabric to desired dimensions in both width and
length, and heatsets the spandex and 2GT polyester fibers by
heating them to about 180 degrees C. or more for a typical
residence time of about 60 to about 120 seconds.
[0027] In the process of FIG. 4, final fabric heatsetting 56 is the
step that determines the final physical properties of the fabric,
including basis weight, elongation, stability and appearance. For
2GT polyester-spandex single-jersey knit fabrics with spandex
plated in every knit course, and for top weight garments,
commercially-useful physical properties include the following:
[0028] basis weights from about 160 to about 330 g/m2,
[0029] minimum elongation of about 80% in the length (warp)
direction,
[0030] spandex content from about 4% to about 15% of the total
fabric weight, and
[0031] shrinkage after washing and drying of about 3% or less in
width and length.
[0032] Fabric physical properties in these ranges can be readily
achieved by final tenter-frame heatsetting. As noted above,
however, the heatsetting operation significantly reduces the dye
washfastness of 2GT polyester-spandex knit fabrics, and it is
generally not possible to achieve dye washfastness ratings of 4 to
5, particularly for SE and S-rated (including commercial high
energy dyes) that are of deep color and/or shade.
[0033] FIG. 5 shows a process that eliminates the pre-heat setting
and the final heat setting step, thereby improving the dye
washfastness of the fabric. The selection of the knitting method
used in the invention depends on the `wet-finishing` conditions of
the process steps after knitting. Wet-finishing refers to all
process operations in which the fabric is wet, such as scouring,
bleaching, dyeing and reduction-clearing operations.
[0034] In a first embodiment the total draft of the spandex yarn in
knitting can be about 2.0.times. or less and the liquid
temperatures in any of the wet-finishing steps, including dyeing,
may range from about 80 to about 100 degrees C. In a second
embodiment the total draft of the spandex yarn in knitting may be
about 2.5.times. or less and the liquid temperature of the dyeing
step may range from about 110 to about 135 degrees C.
[0035] FIG. 2 shows in schematic form one feed position 20 of a
circular knitting machine having a series of knitting needles 22
that move reciprocally as indicated by the arrow 24 in response to
a cam (not shown) below a rotating cylinder (not shown) that holds
the needles. In a circular knitting machine, there are multiple
numbers of these feed positions arranged in a circle, so as to feed
individual knitting positions as the knitting needles, carried by
the moving cylinder, are rotated past the positions.
[0036] For plating knit operations, a spandex yarn 12 and a 2GT
polyester fully drawn, or hard, yarn 14 are delivered to the
knitting needles 22 by a carrier plate 26. The carrier plate 26
simultaneously directs both yarns to the knitting position. The
spandex yarn 12 and 2GT polyester yarn 14 are introduced to the
knitting needles 22 at the same or at a similar rate to form a
single jersey knit stitch 10 like that shown in FIG. 1.
[0037] The 2GT polyester yarn 14 is delivered from a wound yarn
package 28 to an accumulator 30 that meters the yarn to the carrier
plate 26 and knitting needles 22. The 2GT polyester yarn 14 passes
over a feed roll 32 and through a guide hole 34 in the carrier
plate 26. Optionally, more than one 2GT polyester yarn may be
delivered to the knitting needles via different guide holes in the
carrier plate 26.
[0038] The spandex can be any commercially available elastane
product for circular knitting, such as Lycra.RTM. spandex types 162
and 169, available from INVISTA S. r. l. of Wichita, Kans. and
Wilmington, Del.
[0039] The spandex 12 is delivered from a surface driven package 36
and past a broken end detector 39 and change of direction roll(s)
37 to a guide slot 38 within the carrier plate 26. The feed tension
of the spandex 12 is measured between the detector 39 and drive
roll 37, or alternatively between the surface driven package 36 and
roll 37 if the broken end detector is not used. The guide hole 34
and guide slot 38 are separated from one another in the carrier
plate 26 so as to present the hard yarn 14 and spandex 12 to the
knitting needles 22 in side by side, generally parallel relation
(plated).
[0040] The spandex stretches (drafts) when it is delivered from the
supply package to the carrier plate and in turn to the knit stitch
due to the difference between the stitch use rate and the feed rate
from the spandex supply package. The ratio of the 2GT polyester
yarn supply rate (meters/min) to the spandex supply rate is
normally 2.5 to 4 times (2.5.times. to 4.times.) greater, and is
known as the machine draft. This corresponds to spandex elongation
of 150% to 300%, or more. The feed tension in the spandex yarn is
directly related to the draft (elongation) of the spandex yarn.
This feed tension is typically maintained at values consistent with
high machine drafts for the spandex.
[0041] In two embodiments of the methods of the invention, the
total spandex draft can be about 2.0.times. or less, or about
2.5.times. or less, respectively. These draft values are for the
total draft of the spandex, which may include any drafting or
drawing of the spandex that is included in the supply package of
as-spun yarn. The value of residual draft from spinning is termed
package relaxation, "PR", and it typically ranges from 0.05 to 0.15
for the spandex used in circular knit, elastic, single jersey
fabrics. The total draft of the spandex in the fabric is therefore
MD*(1+PR), where "MD" is the knitting machine draft. The knitting
machine draft is the ratio of hard yarn feed rate to spandex feed
rate, both from their respective supply packages.
[0042] Because of its stress-strain properties, spandex yarn drafts
(draws) more as the tension applied to the spandex increases;
conversely, the more that the spandex is drafted, the higher the
tension in the yarn. A typical spandex yarn path, in a circular
knitting machine, is schematically shown in FIG. 2. The spandex
yarn 12 is metered from the supply package 36, over or through a
broken end detector 39, over one or more change-of-direction rolls
37, and then to the carrier plate 26, which guides the spandex to
the knitting needles 22 and into the stitch. There is a build-up of
tension in the spandex yarn as it passes from the supply package
and over each device or roller, due to frictional forces imparted
by each device or roller that touches the spandex. The total draft
of the spandex at the stitch is related therefore to the sum of the
tensions throughout the spandex path.
[0043] The spandex feed tension is measured between the broken end
detector 39 and the roll 37 shown in FIG. 2. Alternatively, the
spandex feed tension is measured between the surface driven package
36 and roll 37 if the broken end detector 39 is not used. The
higher this tension is set and controlled, the greater the spandex
draft will be in the fabric, and vice versa. Suitable ranges for
this feed tension includes from about 2 to 4 cN for 22 dtex
spandex, and from about 4 to 6 cN for 44 dtex spandex in commercial
circular knitting machines. With these feed tension settings and
the additional tensions imposed by subsequent yarn-path friction,
the spandex in commercial knitting machines normally will be
drafted significantly more than 2.5.times..
[0044] Minimizing the spandex friction between the supply package
and the knit stitch helps keep the spandex feed tensions
sufficiently high for reliable spandex feeding when the spandex
draft in about 2.5.times. or less.
[0045] The structural design of a circular knit fabric can be
characterized in part by the "openness" of each knit stitch. This
"openness" may be related to the percentage of the area that is
open versus that which is covered by the yarn in each stitch (see,
e.g., FIGS. 1 and 3), and is thus related to fabric basis weight
and elongation potential. For rigid, non-elastic weft knit fabrics,
the Cover Factor ("Cf") is well known as a relative measure of
openness. The Cover Factor is a ratio and is defined as:
Cf={square root}(tex).div.L
[0046] where tex is the grams weight of 1000 meters of the 2GT
polyester yarn and is also equal to 10*dtex, and L is the stitch
length in millimeters. FIG. 3 is a schematic of a single knit
jersey stitch pattern. One of the stitches in the pattern has been
highlighted to show how the stitch length, "L" is defined.
[0047] The knitting method can produce commercially useful circular
knit, elastic, single jersey fabrics plated from bare spandex and
2GT polyester yarn without heat setting with spandex draft at about
2.0.times. or less in one embodiment, and at 2.5.times. or less in
another embodiment for knit fabric is designed and manufactured
within the following limits:
[0048] The Cover Factor, which characterizes the openness of the
knit structure, can be between about 1.1 and about 1.6, for example
between about 1.2 and about 1.4;
[0049] The 2GT polyester yarn decitex may be from about 55 to about
165;
[0050] The spandex decitex may range from about 17 to about 44:
[0051] The content of spandex in the fabric, on a % weight basis,
can be from about 4% to about 15%;
[0052] While not wishing to be bound by any one theory, it is
believed that the hard yarn in the knit structure resists the
spandex force that acts to compress the knit stitch. The
effectiveness of this resistance is related to the knit structure,
as defined by the Cover Factor. For a given 2GT polyester yarn
decitex, the Cover Factor is inversely proportional to the stitch
length, L. This length is adjustable on the knitting machine, and
is therefore a key variable for control in this process.
[0053] After knitting a circular knit, elastic, single jersey
fabric of plated spandex with 2GT polyester 62, the tubular fabric
can be scoured in a cleaning solution, typically in a jet dye
machine 64, FIG. 5. Bleaching of the fabric is also an optional
operation in this equipment. These operations are well known to
those familiar with the art, and standard methods are satisfactory
for the process.
[0054] The process may include dyeing at atmospheric conditions or
at elevated temperatures and pressures 64. Jet dyeing of 2GT
polyester and 2GT polyester-spandex fabrics is well known to those
who practice the art. Fabric and dye liquor are typically loaded
into a jet-dye machine at weight ratios ranging from 1:10 to 1:15,
which is the ratio of the weight of the fabric to the weight of the
dye liquor. For the purpose of this invention, azo- or
anthraquinone-disperse dyes are specified. The temperature of the
dye liquor may be typically about 130 degrees C., but it can range
from about 110 to about 135 degrees C., depending on the dye color
and type. Dyeing conditions of temperature rise/decline rates and
residence times at maximum temperatures are presumed to be best
industry practice for the dyes used, and no special dyeing
conditions or steps are needed for the process of this
invention.
[0055] Standard industry practices are suitable for the dewatering
66 and slitting steps 68.
[0056] The drying step 70 can be operated with controlled overfeed
in the length (machine) direction so that the fabric stitches are
free to move and rearrange without tension. A flat, non-wrinkled or
non-buckled fabric may emerge after drying. These techniques are
familiar to those skilled in the art. A tenter-frame can be used to
provide fabric overfeed during drying. The objective of the drying
step can be to dry the fabric without the high temperatures that
can also heatset the fabric and cause thermomigration of dye
molecules from the interior of the 2GT polyester and spandex fibers
to the surface of said fibers. To enhanced dye washfastness
ratings, the fabric may be heated, until dry, at a temperature of
about 130 degrees C. or less, and typically at a temperature
between about 120 and about 125 degrees C.
[0057] The knit 2GT polyester-spandex fabric can have good dye
washfastness ratings, as well as physical properties that are
commercially useful. For example, the product of this process has
fabric stain ratings typically in the range of 3.5 to 5 with
exception at about 3.0. The fabrics can have commercially-useful
physical properties as follows:
[0058] Basis weight in the range of about 160 to about 330 g/m2
[0059] Elongation in the warp (length) direction of about 80% or
more, and preferably from about 80% to about 130%
[0060] Shrinkage after washing and drying of about 3% or less and
typically less than 3% in both length and width.
[0061] The process provides this combination of product with the
flexibility to use azo and anthraquinone dyes of deep color shades
(including high energy dyes).
EXAMPLES
[0062] The following examples are to be regarded as illustrative in
nature and not as restrictive.
[0063] Fabric Knitting and Finishing
[0064] Circular knit elastic single jersey fabrics with bare
spandex plated with hard yarn for the examples were knit on a Pai
Lung Circular Knitting Machine, Model PL-XS3B/C, with 26 inches
cylinder diameter, 24 gauge, and 78 yarn feed positions. The
machine was operated at 26 rpm.
[0065] The broken end detector in each spandex feed path (see FIG.
2) was either adjusted to reduce sensitivity to yarn tension, or
removed from the machines for these examples. The broken end
detector was a type that contacted the yarn, and therefore induced
tension in the spandex.
[0066] The spandex feed tension was measured between the spandex
supply package 36 and the roller guide 37 (FIG. 2) with a Zivy
digital tension meter, model number, EN-10. For examples of the
invention, the spandex feed tensions were maintained at 1 gram or
less for 20 and 30-denier spandex. These tensions were sufficiently
high for reliable and continuous feeding of the spandex yarn to the
knitting needles, and sufficiently low to draft the spandex only
about 2.5.times. or less. We found that when the feed tensions were
too low, the spandex yarn wrapped around the roller guides at the
supply package and could not be reliably fed to the circular
knitting machine.
[0067] All the knitted fabrics were scoured, dyed and dried per the
process 60 in FIG. 5.
[0068] Fabrics were scoured in a jet dye machine (Tong Geng
Enterprise Co. Ltd. TGRU-HAF-1-30) at 90.degree. C. for 20 minutes.
The concentration of ingredients in the scouring solution, per
liter of water, were as follows: 0.75 g/l Humectol Lys (Clariant),
2.0 g/l Na2CO3 (Sesoda), 0.5 g/l Imacol S (Clariant), 0.5 g/l
Antimussol HT2S (Clariant), and 0.5g/l Glacial acetic acid.
[0069] The fabrics were dyed individually, and, the same machine
was used for each example. For examples A1, B5, C9, and D13,
Brilliant Red-SR GL (Clariant), a middle energy dye type SE (or C),
was used at a 3.5% level based on the weight of fabric (OWF). For
examples A2, B6, C10, and D14, Rubine SWF (Clariant) at 3.0% OWF
and Black SWF (Clariant) at 1.5% OWF were used. Both these are
middle energy dyes, type SE (or C). For examples A3, B7, C11, and
D15, Dark Blue RD2RE 300% (Clariant), a high energy dye type S (or
D), was used at 3.5% OWF. For examples, A4, B8, C12, and D16, Black
RD-3GE 300% (Clariant), a high energy dye type S (or D), was used
at 3.57% OWF. The liquor ratio was 1:12. The concentrations of
ingredients in the dye liquor for each fabric, per liter of water,
were as follows: dye as given above, 0.5 g/l Imacol S (Clariant),
and 2.0 g/l Sandacid PB (Clariant). The dyebath pH was 4.12. The
fabric cycle time was 51 seconds/cycle. The bath temperature was
raised from room Temperature to 130.degree. C. at the rate of
1.degree. C. per minute. The process was operated at 130.degree. C.
for 30 minutes, followed by cool down to 70.degree. C. at the
cooldown rate of 1.degree. C. per minute. The dyebath was then
drained and the machine recharged with cool water, followed by
rinsing of the fabric for 10 minutes. The water was subsequently
drained to prepare the fabric for reduction clearing.
[0070] The fabric was subsequently reduction cleared in the jet dye
machine in a clearing solution at 85.degree. C. for 30 minutes. The
ingredients in the solution, per liter of water, were as follows:
3.0 g/l Eriopon OS (Ciba), 2.0 g/l Na.sub.2Co.sub.3 (Sesoda), 3.33
ml/l NaOH (45%), 0.5 g/l Antimussol HT2S (Clariant), and 6.0 g/l
NaS.sub.2O.sub.4. The solution temperature was raised from room
temperature to 85.degree. C. at a rate of 1.degree. C. per minute
and held there for 30 minutes. The solution was subsequently cooled
down to 60.degree. C. at the rate of 1.degree. C. per minute, and
then drained. Following that, the fabric was neutralized with
glacial acetic acid for 10 minutes, then rinsed with clean water
for 5 minutes. The wet fabrics were then de-watered by centrifuge,
for 8 minutes or until water is removed depending on fabric and
diameter and speed of equipment, as per normal practice. For the
final step, a lubricant (softener) was padded onto the fabrics in a
77-liter water solution with Sandoperm SEI (Clariant, 1155 g). The
fabrics were then dried in a tenter oven at about 130.degree. C.
for about 30 seconds, at about 50% fabric overfeed.
[0071] The above procedure and additives will be familiar to those
experienced in the art of textile manufacturing and circular
knitting of single jersey knit fabrics.
[0072] Analytical Methods
[0073] Stain Ratings--Stain ratings ranging from 1.0 to 5.0 are
determined by grading white multifiber fabric samples that are
stained when included in an accelerated wash test. The wash test
conditions and stain rating methodologies are those defined by the
American Association of Textile Chemists and Colorists (AATCC) in
AATCC Test Method 61-1996-2A. This method is herein incorporated in
its entirety by reference.
[0074] Spandex Draft--The following procedure, conducted in an
environment at 20.degree. C. and 65% relative humidity, is used to
measure the spandex drafts in the Examples.
[0075] De-knit (unravel) a yarn sample of 200 stitches (needles)
from a single course, and separate the spandex and hard yarns of
this sample. A longer sample is de-knit, but the 200 stitches are
marked at beginning and end.
[0076] Hang each sample (spandex or hard yarn) freely by attaching
one end onto a meter stick with one marking at the top of the
stick. Attach a weight to each sample (0.1 g/denier for hard yarn,
0.001 g/denier for spandex). Lower the weight slowly, allowing the
weight to be applied to the end of the yarn sample without
impact.
[0077] Record the length measured between the marks. Repeat the
measurements for 5 samples each of spandex and hard yarn.
[0078] Calculate the average spandex draft according to the
following formula:
Draft=(Length of hard yarn between marks).div.(Length of spandex
yarn between marks).
[0079] If the fabric has been heat set, as in the prior art, it is
usually not possible to measure the in-fabric spandex draft. This
is because the high temperatures needed for spandex heat setting
will soften the spandex yarn surface and the bare spandex will tack
to itself at stitch crossover points 16 in the fabric (FIG. 1).
Because of such multiple tack points, one cannot de-knit fabric
courses and extract yarn samples.
[0080] Fabric Weight--Knit Fabric samples are die-punched with a 10
cm diameter die. Each cut-out knit fabric sample is weighed in
grams. The "fabric weight" is then calculated as grams/square
meters.
[0081] Spandex Fiber Content--Knit fabrics are de-knit manually.
The spandex is separated from the companion hard yarn and weighed
with a precision laboratory balance or torsion balance. The spandex
content is expressed as the percentage of spandex weight to fabric
weight.
[0082] Fabric Elongation--The elongation is measured in the warp
direction only. Three fabric specimens are used to ensure
consistency of results. Fabric specimens of known length are
mounted onto a static extension tester, and weights representing
loads of 4 Newtons per centimeter of length are attached to the
specimens. The specimens are exercised by hand for three cycles and
then allowed to hang free. The extended lengths of the weighted
specimens are then recorded, and the fabric elongation is
calculated.
[0083] Shrinkage--Two specimens, each of 60.times.60 centimeters,
are taken from the knit fabric. Three size marks are drawn near
each edge of the fabric square, and the distances between the marks
are noted. The specimens are then sequentially machine washed 3
times in a 12-minute washing machine cycle at 40.degree. C. water
temperature and air dried on a table in a laboratory environment.
The distances between the size marks are then re-measured to
calculate the amount of shrinkage.
[0084] Face Curl--A 4-inch.times.4-inch (10.16 cm.times.10.16 cm)
square specimen is cut from the knit fabric. A dot is placed in the
center of the square, and an `X` is drawn with the dot as the
center of the `X`. The legs of the `X` are 2 (5.08 cm) inches long
and in line with the outside corners of the square. The X is
carefully cut with a knife, and then the fabric face curls of two
of the internal points created by the cut are measured immediately
and again in two minutes, and averaged. If the fabric points curl
completely in a 360.degree. circle, the curl is rated as 1.0; if it
curls only 180.degree., the curl is rated 1/2; and so on.
EXAMPLES 1-16
[0085] Table 1 below sets forth the knitting conditions for the
example knit fabrics. Lycra.RTM. types 169B and 162C were used for
the spandex feeds (commercially available from Invista S. . r. l.
of Wichita, Kans. and Wilmington, Del.). Lycra.RTM. deniers were 40
and 30, or 44 dtex and 33 dtex, respectively. The stitch length, L,
was a machine setting. Spandex feed tensions are listed in grams
and 1.00 grams equal 0.98 centiNewtons(cN).
[0086] Table 2 summarizes the major finishing conditions of the
fabrics. Include description of the specifics for each group of
fabrics. Examples, A1, A2, B5, B6, C9, C10, D13, and D14 were dyed
with middle energy dyes otherwise known in the industry as SE (or
C) type dyes. Examples A3, A4, B7, B8, C11, C12, D15, and D16 were
dyed with high energy dyes otherwise known in the industry as S (or
D) type dyes.
1TABLE 2 FINISHING CONDITIONS Liquor Heat Set, Jet Dyeing Energy
Dye Bath Liquor Temp, .degree. C., Dry, .degree. C., Example Dye
Type Rating Color Ratio .degree. C. 45 sec. 120 sec. A1 Disperse
Middle, Blue 1:12 130 below SE 130 A2 Disperse Middle, Black 1:12
130 below SE 130 A3 Disperse High, S Red 1:12 130 below 130 A4
Disperse High, S Purple 1:12 130 below 130 B5 Disperse Middle, Blue
1:12 130 170 SE B6 Disperse Middle, Black 1:12 130 170 SE B7
Disperse High, S Red 1:12 130 170 B8 Disperse High, S Purple 1:12
130 170 C9 Disperse Middle, Blue 1:12 130 below SE 130 C10 Disperse
Middle, Black 1:12 130 below SE 130 C11 Disperse High, S Red 1:12
130 below 130 C12 Disperse High, S Purple 1:12 130 below 130 D13
Disperse Middle, Blue 1:12 130 170 SE D14 Disperse Middle, Black
1:12 130 170 SE D15 Disperse High, S Red 1:12 130 170 D16 Disperse
High, S Purple 1:12 130 170
[0087] Table 3 summarizes key results of the tests finished
fabrics.
2TABLE 3 FABRIC RESULTS Fabric Lycra .RTM. Stain Lycra .RTM. Basis
Maximum spandex Shrinkage Face Curl, Rating Stain Stain Stain Stain
Ex- spandex Weight, Length Content in %, Warp Fraction to Rating to
Rating to Rating to Rating ample Draft g/m2 Elongation % Fabric, %
by Weft of 360.degree. cotton nylon polyester acrylic to wool A1
2.5 298 104 7.2 -1 .times. -1 0.0 4.5 3.0 4.5 4.5 4.0 A2 2.5 297
101 7.2 -2 .times. -1 0.0 4.5 3.5 4.5 4.5 4.0 A3 2.5 300 103 7.2 -1
.times. -1 0.0 4.5 3.5 4.5 4.5 4.5 A4 2.5 298 100 7.2 -2 .times. -1
0.0 4.5 4.5 4.5 4.5 4.5 B5 3.5 271 102 5.5 -1 .times. 0 0.0 4.5 2.0
3.0 4.5 3.5 B6 3.5 279 104 5.5 -1 .times. 0 0.0 4.5 2.5 3.5 4.5 4.0
B7 3.5 279 107 5.5 -1 .times. 0 0.0 4.0 2.0 4.0 4.5 3.5 B8 3.5 282
108 5.5 -1 .times. 0 0.0 4.5 2.5 3.5 4.5 4.0 C9 2.5 306 106 9.1 0
.times. 0 0.0 4.5 3.0 4.5 4.5 4.0 C10 2.5 305 104 9.1 0 .times. -1
0.0 4.5 3.0 4.5 4.5 4.0 C11 2.5 305 105 9.1 0 .times. -1 0.0 4.5
4.0 4.5 4.5 4.5 C12 2.5 309 104 9.1 0 .times. -1 0.0 4.5 4.0 4.5
4.5 4.5 D13 3.5 271 85 6.7 0 .times. 0 0.0 4.5 3.0 4.5 4.5 4.0 D14
3.5 263 79 6.7 0 .times. 0 0.0 4.5 2.5 4.0 4.5 4.0 D15 3.5 266 84
6.7 0 .times. 0 0.0 4.5 2.5 4.5 4.5 4.5 D16 3.5 251 73 6.7 0
.times. 0 0.0 4.5 3.0 4.0 4.5 4.0
EXAMPLE A1
[0088] The fabric was knit using 150D/288f microdenier 2GT
polyester and 33 dtex Lycra.RTM. spandex. The draft of the spandex
in the fabric was 2.5.times.. The fabric of Example A1 was dyed
with a middle energy, SE-rated dye to a blue shade and finished
according to the process schematically shown in FIG. 5. The fabric
basis weight for Example A1 is 298 g/m.sup.2 with acceptable
shrinkage. Stain rating to nylon is 3.0.
EXAMPLE A2
[0089] The fabric of Example A1 was dyed with a middle energy,
SE-rated dye to a black shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
A2 is 297 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 3.5.
EXAMPLE A3
[0090] The fabric of Example A1 was dyed with a high energy,
S-rated dye to a red shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
A3 is 300 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 3.5.
EXAMPLE A4
[0091] The fabric of Example A1 was dyed with a high energy,
S-rated dye to a purple shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
A4 is 298 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 4.5.
EXAMPLE B5
[0092] The fabric was knit using 150D/288f microdenier 2GT
polyester and 33 dtex Lycra.RTM. spandex. The draft of the spandex
in the fabric was 3.5.times.. The fabric of Example B5 was dyed
with a middle energy, SE-rated dye to a blue shade and finished
according to the process schematically shown in FIG. 5. The fabric
basis weight for Example B5 is 271 g/m.sup.2 with acceptable
shrinkage. Stain rating to nylon is 2.
EXAMPLE B6
[0093] The fabric of example B5 was dyed with a middle energy,
SE-rated dye to a black shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
B6 is 279 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 2.5.
EXAMPLE B7
[0094] The fabric of example B5 was dyed with a high energy,
S-rated dye to a red shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
B7 is 279 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 2.
EXAMPLE B8
[0095] The fabric of example B5 was dyed with a high energy,
S-rated dye to a purple shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for
EXAMPLE B8 is 282 g/m.sup.2 with acceptable shrinkage. Stain rating
to nylon is 2.5.
EXAMPLE C9
[0096] The fabric was knit using 150D/48f 2GT polyester and 44 dtex
Lycra.RTM. spandex. The draft of the spandex in the fabric was
2.5.times.. The fabric of Example C9 was dyed with a middle energy,
SE-rated dye to a blue shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
C9 is 306 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 3.0.
EXAMPLE C10
[0097] The fabric of Example C9 was dyed with a middle energy,
SE-rated dye to a black shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
C10 is 305 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 3.0.
EXAMPLE C11
[0098] The fabric of Example C9 was dyed with a high energy,
S-rated dye to a red shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
C11 is 305 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 4.0.
EXAMPLE C12
[0099] The fabric of Example C9 was dyed with a high energy,
S-rated dye to a purple shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
C12 is 309 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 4.0.
EXAMPLE D13
[0100] The fabric was knit using 150D/48f 2GT polyester and 44 dtex
Lycra.RTM. spandex. The draft of the spandex in the fabric was
3.3.times.. The fabric was dyed with a middle energy, SE-rated dye
to a blue shade and finished according to the process schematically
shown in FIG. 5. The fabric basis weight for Example D13 is 271
g/m.sup.2 with acceptable shrinkage. Stain rating to nylon is
3.0.
EXAMPLE D14
[0101] The fabric of example D13 was dyed with a middle energy,
SE-rated dye to a black shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
D14 is 263 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 2.5.
EXAMPLE D15
[0102] The fabric of example D13 was dyed with a high energy,
S-rated dye to a red shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
D15 is 266 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 2.5.
EXAMPLE D16
[0103] The fabric of example D13 was dyed with a high energy,
S-rated dye to a purple shade and finished according to the process
schematically shown in FIG. 5. The fabric basis weight for Example
D16 is 251 g/m.sup.2 with acceptable shrinkage. Stain rating to
nylon is 3.0.
* * * * *