Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
I
TEXTILE MATERIALS CONTAINING ARAMID FIBERS AND DYED
POLYPHENYLENE SULFIDE FIBERS
TECHNICAL FIELD OF THE INVENTION
[0001] This application relates to textile materials containing aramid
fibers and
dyed polyphenylene sulfide fibers and methods for producing the same.
BACKGROUND
[0002] Polyphenylene sulfide is a thermoplastic polymer that exhibits many
desirable properties. For example, polyphenylene sulfide exhibits resistance
to heat,
various chemicals (e.g., acids, alkalis, and bleaches), mildew, aging, UV
exposure
(e.g., sunlight), and abrasion. Due to its thermoplastic nature and the
desirable
properties, polyphenylene sulfide polymer has been extruded into fibers
suitable for
use in making textile materials. These polyphenylene sulfide fibers have been
used
in industrial textile materials, such as high temperature filtration media and
automotive hose reinforcement, for many years. However, despite the many
advantages offered by the polyphenylene sulfide polymer, the textile fibers
made
from the polymer have not found practical use in apparel or decorative textile
applications. The main reason for this lack of use is that no practical means
for
dyeing polyphenylene sulfide polymers has been developed.
[0003] A need therefore remains for a method of dyeing polyphenylene
sulfide
fibers that produces fibers with the full range of colors and shades desired
for
apparel and decorative textile applications and exhibiting the colorfastness
needed
for such applications and combining them with aramid fibers for a blended
yarn. The
invention described in this application seeks to provide such a method and the
dyed
polyphenylene sulfide fibers produced by such a method.
BRIEF SUMMARY OF THE INVENTION
[0004] In a first embodiment, the invention provides a textile material
comprising a plurality of yarns containing an intimate blend of dyed
polyphenylene
sulfide fibers and aramid fibers, wherein the polyphenylene sulfide fibers
have a
Date Recue/Date Received 2022-01-18
2
cross-sectional area, the polyphenylene sulfide fibers comprise a disperse dye
that is
distributed substantially evenly across the cross-sectional area of the
fibers, and the
disperse dye is selected from the group consisting of disperse dyes having a
molar
mass of about 350 g/mol or more, disperse dyes comprising a nitro group, and
mixtures thereof.
[0005] In a second embodiment, the invention provides a method for dyeing
polyphenylene sulfide fibers, the method comprising the steps of:
(a) providing a plurality of polyphenylene sulfide fibers and aramid
fibers;
(b) spinning the blend of fibers into a plurality of yarns;
(c) forming the yarns into a textile material;
(d) subjecting the textile material to a polyphenylene sulfide dyeing
process comprising:
(i) providing a dye liquor comprising a liquid medium and a disperse
dye selected from the group consisting of disperse dyes having a molar mass of
about 350 g/mol or more, disperse dyes comprising a nitro group, and mixtures
thereof;
(ii) applying the dye liquor to the textile material;
(iii) heating the textile material under ambient atmosphere to a
temperature sufficient to evaporate substantially all of the liquid medium
from
the textile material; and
(iv) heating the textile material under ambient atmosphere to a
temperature of about 180 C or more to fix the disperse dye to the
polyphenylene sulfide fibers;
DETAILED DESCRIPTION OF THE INVENTION
[0006] In a first embodiment, the invention provides a textile material
comprising yarns, the yarns comprising a plurality of aramid fibers and dyed
polyphenylene sulfide fibers (the aramid fibers may be dyed or undyed).
By "yarn" is meant an assemblage of fibers spun or twisted together to form a
continuous strand, which can be used in weaving, knitting, braiding, or
plaiting, or
otherwise made into a textile material or fabric. The textile material of this
first
Date Recue/Date Received 2022-01-18
3
embodiment can take any suitable form. For example, the plurality of dyed
polyphenylene sulfide fibers and aramid fibers can be consolidated to provide
a yarn.
In such an embodiment, the yarn can contain other fibers in addition to the
dyed
polyphenylene sulfide fibers and aramid fibers, as is described in further
detail
below. In another embodiment, the plurality of aramid fibers and dyed
polyphenylene sulfide fibers can be consolidated into a nonwoven textile
material.
The textile material can also be a woven textile material comprising a
plurality of
interlaced yarns, at least one of which contains the aramid fibers and dyed
polyphenylene sulfide fibers. The textile material can also be a knit textile
material
comprising one or more interlooped yarns, at least one of which contains the
aramid
fibers and dyed polyphenylene sulfide fibers. Preferably, the weight range of
the
fabric is between about 2.5 and 20 oz/yd2, more preferably between about 4 and
12
oz/yd2.
[0007] The dyed polyphenylene sulfide fibers can comprise any suitable
polyphenylene sulfide polymer. The polyphenylene sulfide polymer can have any
suitable molar mass. Preferably, the polyphenylene sulfide polymer has a mass
average molar mass of about 20,000 g/mol or more. More preferably, the
polyphenylene sulfide polymer has a mass average molar mass of about 30,000
g/mol or more, about 40,000 g/mol or more, or about 50,000 g/mol or more.
Preferably, the polyphenylene sulfide polymer has a mass average molar mass of
about 100,000 g/mol or less. More preferably, the polyphenylene sulfide
polymer
has a mass average molar mass of about 80,000 g/mol or less, about 70,000
g/mol
or less, or about 60,000 g/mol or less. In a particularly preferred
embodiment, the
polyphenylene sulfide polymer has a mass average molar mass of about 40,000
g/mol to about 60,000 g/mol. The polyphenylene sulfide polymer can have any
suitable melt viscosity. Preferably, the polyphenylene sulfide polymer has a
melt
viscosity of about 1,000 poise or more when measured at 300 C and an apparent
shear rate of 400 S-1 in accordance with ASTM Test Method 3835. More
preferably,
the polyphenylene sulfide polymer has a melt viscosity of about 1,000 poise to
about
3,000 poise or about 1,000 poise to about 2,200 poise when measured as
described
above.
Date Recue/Date Received 2022-01-18
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[0008] The polyphenylene sulfide polymer can exhibit any suitable degree of
crystallinity. Preferably, the percent crystallinity of the polyphenylene
sulfide polymer
is 10% or more. More preferably, the percent crystallinity of the
polyphenylene
sulfide polymer is about 20% or more, about 25% or more, or about 30% or more.
The percent crystallinity of the polyphenylene sulfide polymer preferably is
about
80% or less. More preferably, the percent crystallinity of the polyphenylene
sulfide
polymer is about 75% or less. Thus, in a series of preferred embodiments, the
percent crystallinity of the polyphenylene sulfide polymer is from 10% to
about 80%,
about 20% to about 80%, or about 30% to about 75%.
[0009] The dyed polyphenylene sulfide fibers of the textile material
comprise
at least one dye. The dye can be any suitable dye, but disperse dyes are
particularly
preferred. Preferably, the dye is a disperse dye selected from the group
consisting
of disperse dyes having a molar mass of about 350 g/mol or more, disperse dyes
comprising a nitro group, and mixtures thereof. In another preferred
embodiment,
the dye is a disperse dye selected from the group consisting of disperse dyes
having
a molar mass of about 400 g/mol or more, disperse dyes comprising a nitro
group,
and mixtures thereof. While not wishing to be bound to any particular
mechanism or
theory, it has been observed that disperse dyes having a higher molar mass
(e.g.,
about 350 g/mol or more or about 400 g/mol or more) and/or a polar nature
(such as
disperse dyes containing a nitro group) are capable of satisfactorily dyeing
the
polyphenylene sulfide fibers, whereas disperse dyes that do not possess either
of
these characteristics are not. For example, it has been observed that dyes
that do
not possess either of these characteristics do not become sufficiently fixed
in the
polyphenylene sulfide fiber. With the exception of nitrodiphenylamine disperse
dyes,
the disperse dye preferably has a boiling point of 590 C or more, more
preferably
about 600 C or more. With the exception of nitrodiphenylamine disperse dyes,
the
disperse dye preferably has a flash point of 300 C or more, more preferably
about
310 C or more. In a particular embodiment, the disperse dye has a boiling
point of
590 C or more (e.g., about 600 C or more) and a flash point of 300 C or
more
(e.g., about 310 C or more).
[0010] The disperse dye can be any suitable disperse dye that possesses one
or more of the characteristics described above. In a more specific preferred
Date Recue/Date Received 2022-01-18
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embodiment, the disperse dye is selected from the group consisting of azo dyes
(e.g., azothiophene dyes, azobenzothiazole dyes), diazo dyes, anthraquinone
dyes,
nitro dyes (e.g., nitrodiphenylamine dyes), quinoline dyes, dibenzofuran dyes,
naphthalimide dyes (e.g., aminoketone dyes), and mixtures thereof. Specific
disperse dyes that have been found useful in dyeing the polyphenylene sulfide
fibers
include, but are not limited to, C.I. Disperse Red 356, C.I. Disperse Red 167,
C.I.
Disperse Blue 77, C.I. Disperse Orange 30, C.I. Disperse Orange 44, C.I.
Disperse
Red 91, C.I. Disperse Blue 77, C.I. Disperse Blue 27, C.I. Disperse Blue 60,
C.I.
Disperse Yellow 86, C.I. Disperse Yellow 42, C.I. Disperse Yellow 58, C.I.
Disperse
Yellow 163, C.I. Disperse Red 86, C.I. Disperse Violet 57, C.I. Disperse Red
159,
C.I. Disperse Red 279, C.I. Disperse Yellow 114, C.I. Disperse Blue 56, C.I.
Disperse Blue 165, C.I. Disperse Red 153, C.I. Disperse Brown 1, C.I. Disperse
Violet 33, C.I. Disperse Red 92, and C.I. Disperse Blue 87. Any of the above-
mentioned dyes can be used in combination to produce polyphenylene sulfide
fibers
and textile materials exhibiting the desired color and shade.
[0011] The disperse dye preferably is distributed substantially evenly
throughout the thickness of the polyphenylene sulfide fibers. In other words,
the
disperse dye preferably is distributed substantially evenly across the cross-
sectional
area of the polyphenylene sulfide fibers. This distribution of the disperse
dye within
the polyphenylene sulfide fibers is believed to be unique. For example, prior
attempts to dye polyphenylene sulfide fibers have relied upon surrounding the
polyphenylene sulfide polymer with a sheath of an easily-dyed polymer (e.g., a
polyamide). In such products, the dye only penetrates and fixes in the sheath,
and
the polyphenylene sulfide polymer remains undyed (or contains very little dye
at the
interface between the polyphenylene polymer and the sheath). The distribution
of
the disperse dye through the thickness or across the cross-sectional area can
be
determined by any suitable technique. For example, individual polyphenylene
sulfide
fibers can be sectioned and the coloration of the fibers can be examined, for
instance, using an optical microscope. When the coloration of the fibers is
observed
to be substantially even through the thickness or across the cross-sectional
area of
the fibers, one has confirmed that the dye is substantially evenly distributed
through
the thickness or across the cross-sectional area of the fiber.
Date Recue/Date Received 2022-01-18
6
[0012] In another embodiment, the invention provides a textile material
comprising yarns, at least a portion of the yarns comprising a plurality of
aramid
fibers and dyed polyphenylene sulfide fibers (the aramid fibers may be dyed or
undyed). In one embodiment, the textile material comprises at least about 50%
by
weight yarns that contain a plurality aramid fibers and dyed polyphenylene
sulfide
fibers, more preferably at least about 60%, at least about 70%, at least about
90%,
and at least about 95% by weight. The polyphenylene sulfide and aramid fibers
may
have any suitable denier, preferably between 1 and 8 denier, more preferably
between about 1 and 3 denier.
[0013] As used herein, "aramid" is meant a polyamide wherein at least 85%
of
the amide (¨CONN¨) linkages are attached directly to two aromatic rings.
Additives
can be used with the aramid and, in fact, it has been found that up to as much
as 10
percent, by weight, of other polymeric material can be blended with the aramid
or
that copolymers can be used having as much as 10 percent of other diamine
substituted for the diamine of the aramid or as much as 10 percent of other
diacid
chloride substituted for the diacid chloride of the aramid. Suitable aramid
fibers are
described in Man-Made Fibers--Science and Technology, Volume 2, Section titled
Fiber-Forming Aromatic Polyam ides, page 297, W. Black et al., Interscience
Publishers, 1968. Aramid fibers are, also, disclosed in U.S. Pat. Nos.
4,172,938;
3,869,429; 3,819,587; 3,673,143; 3,354,127; and 3,094,511. M-aramid are those
aramids where the amide linkages are in the meta-position relative to each
other,
and p-aramids are those aramids where the amide linkages are in the para-
position
relative to each other. In the practice of this invention the aramids most
often used
are poly(paraphenylene terephthalamide) and poly(metaphenylene
isophthalamide).
[0014] The yarns contain aramid fibers, preferably meta-aramid fibers. The
most well-known meta-aramid fibers are available as NOMEX available from
DuPont. NOMEXE)and related aramid polymers are related to nylon, but
have aromatic backbones, and hence are more rigid and more durable. NOMEX is
produced by condensation reaction from the monomers m-
phenylenediamine and isophthaloyl chloride. Meta-aramids are preferred as they
are inherent flame resistant fibers and are compatible with the polyphenylene
sulfide
fibers and their dyeing processes. The aramid fibers may also preferably be
para-
Date Recue/Date Received 2022-01-18
7
aramid fibers. The most well-known para-aramid fibers are available as KEVLAR
available from DuPont. In another embodiment, the aramid fibers may be a blend
of
meta-aramid and para-aramid fibers. In one embodiment, the aramid fibers are
NOMEX IIIA which is a blend of 93% NOMEXO (meta-aramid), 5% KEVLARO
(para-aramid) +2% P140 carbon fiber (antistatic fiber).
[0015] In another embodiment, the invention provides a textile material
comprising yarns, at least a portion of the yarns comprising a plurality of
polyamide-
imide fibers and dyed polyphenylene sulfide fibers (the polyamide-imide fibers
may
be dyed or undyed). In one embodiment, the textile material comprises at least
about 50% by weight yarns that contain a plurality of polyamide-imide fibers
and
dyed polyphenylene sulfide fibers.
[0016] The textile material of this first embodiment can take any suitable
form.
For example, the plurality of dyed polyphenylene sulfide fibers and polyamide-
imide
fibers can be consolidated to provide a yarn. These polyamide-imide fibers may
be
used with the dyed polyphenylene sulfide fibers or in combination with other
fibers
such as aramid fibers or cellulosic fibers. One such polyamide-imide fiber is
available and marketed under the tradename KERMAL . Polyamide-imide fibers are
typically colored as the fibers are formed as it is very difficult to color
them once
formed into a fiber, yarn, or textile.
[0017] Staple fibers for use in spinning yarns are generally of a
particular
length and of a particular linear density. For use in this invention, the
fibers can have
any length which is adequate for manufacture of spun yarns. Staple lengths of
2.5 to
15.2 centimeters (1 to 6 inches) can be used and lengths of 3.8 to 11.4
centimeters
(1.5 to 4.5 inches) are preferred. In another embodiment, the fibers making up
the
yarns have a staple cut length of between about 30 and 60 mm, more preferably
between about 38 and 52 mm. The yarn formed from the fibers may be any type of
yarn formed by any suitable process. For example, the yarn can be made be a
jet
spun, open end spun, ring spun, vortex spun yarn, it can be Z type twist or S
type
twist; can be single ply, 2 ply, 3 ply, etc. Yarn size preferably ranges from
40 count
to 5 count (cotton yarn count system).
Date Recue/Date Received 2022-01-18
8
[0018] As utilized herein, the term "inherent flame resistant fibers"
refers to
synthetic fibers which, due to the chemical composition of the material from
which
they are made, exhibit flame resistance without the need for an additional
flame
retardant treatment. In one embodiment, the yarns can contain additional
inherent
flame resistant fibers. In such embodiments, the inherent flame resistant
fibers can
be any suitable inherent flame resistant fibers, such as polyoxadiazole
fibers,
polysulfonamide fibers, poly(benzimidazole) fibers, aramid fibers (e.g., para-
aramid
fibers), polypyridobisimidazole fibers, polybenzylthiazole fibers,
polybenzyloxazole
fibers, melamine-formaldehyde polymer fibers, phenol-formaldehyde polymer
fibers,
oxidized polyacrylonitrile fibers, polyamide-imide fibers and combinations,
mixtures,
or blends thereof. In a preferred embodiment, the textile material comprises
aramid
fibers in addition to the polyphenylene sulfide fibers. Other fibers can
additionally be
included into the textile material concluding polyamidimid fibers, phenol-
formaldehyde fibers, melamine fibers, glass fibers, metal fibers, elastomeric
fibers/yarns, and carbon fibers. In some embodiments, the elastomeric yarn is
a
spandex yarn. While in some embodiments the preferred elastomeric fiber yarn
is a
spandex fiber yarn, any fiber generally having stretch and recovery can be
used. As
used herein, "spandex" has its usual definition, that is, a manufactured fiber
in which
the fiber-forming substance is a long chain synthetic polymer composed of at
least
85% by weight of a segmented polyurethane. The textile material may also, in
some
embodiments, comprise a core spun yarn which is a mono or multifilament core
covered with a fiber covering.
[0019] The yarns making up the textile material and the textile material
can
contain any suitable amounts of polyphenylene sulfide fibers and aramid /
polyamide-imide fibers. Preferably, the plurality of yarns comprises at least
about
40% by weight polyphenylene sulfide fibers. In another embodiment, the
plurality of
yarns comprises at least about 50%, at least about 60% or at least about 70%
by
weight polyphenylene sulfide fibers. In another embodiment, the plurality of
yarns
comprises between about 20 and 80% by weight polyphenylene sulfide fibers,
more
preferably between about 40 and 70% weight. In another embodiment, the
plurality
of yarns comprises between about 20 and 80% by weight aramid fibers, more
preferably between about 40 and 70% weight. In another embodiment, the yarns
Date Recue/Date Received 2022-01-18
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contain less than about 80% by weight, more preferably less than about 70%,
less
than about 60%, or less than about 50% by weight of polyphenylene sulfide
fibers.
In another embodiment, the yarns contain less than about 80% by weight, more
preferably less than about 70%, less than about 60%, or less than about 50% by
weight of aramid fibers.
[0020] Preferably, the textile material comprises at least about 40% by
weight
polyphenylene sulfide fibers. In another embodiment, the textile material
comprises
at least about 50%, at least about 60% or at least about 70% by weight
polyphenylene sulfide fibers. In another embodiment, the textile material
comprises
between about 20 and 80% by weight polyphenylene sulfide fibers, more
preferably
between about 40 and 70% weight. In another embodiment, the textile material
comprises between about 20 and 80% by weight aramid fibers, more preferably
between about 40 and 70% weight. In another embodiment, the textile material
contains less than about 80% by weight, more preferably less than about 70%,
less
than about 60%, or less than about 50% by weight of polyphenylene sulfide
fibers.
In another embodiment, the textile material contains less than about 80% by
weight,
more preferably less than about 70%, less than about 60%, or less than about
50%
by weight of aramid fibers.
[0021] The yarns making up the textile material and the textile material
can
contain any suitable amounts of polyphenylene sulfide fibers and polyamide-
imide
fibers. Preferably, the plurality of yarns comprises at least about 40% by
weight
polyphenylene sulfide fibers. In another embodiment, the plurality of yarns
comprises at least about 50%, at least about 60% or at least about 70% by
weight
polyphenylene sulfide fibers. In another embodiment, the plurality of yarns
comprises between about 20 and 80% by weight polyphenylene sulfide fibers,
more
preferably between about 40 and 70% weight. In another embodiment, the
plurality
of yarns comprises between about 20 and 80% by weight polyamide-imide fibers,
more preferably between about 40 and 70% weight. In another embodiment, the
yarns contain less than about 80% by weight, more preferably less than about
70%,
less than about 60%, or less than about 50% by weight of polyphenylene sulfide
fibers. In another embodiment, the yarns contain less than about 80% by
weight,
Date Recue/Date Received 2022-01-18
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more preferably less than about 70%, less than about 60%, or less than about
50%
by weight of polyamide-imide fibers.
[0022] Preferably, the textile material comprises at least about 40% by
weight
polyphenylene sulfide fibers. In another embodiment, the textile material
comprises
at least about 50%, at least about 60% or at least about 70% by weight
polyphenylene sulfide fibers. In another embodiment, the textile material
comprises
between about 20 and 80% by weight polyphenylene sulfide fibers, more
preferably
between about 40 and 70% weight. In another embodiment, the textile material
comprises between about 20 and 80% by weight polyamide-imide fibers, more
preferably between about 40 and 70% weight. In another embodiment, the textile
material contains less than about 80% by weight, more preferably less than
about
70%, less than about 60%, or less than about 50% by weight of polyphenylene
sulfide fibers. In another embodiment, the textile material contains less than
about
80% by weight, more preferably less than about 70%, less than about 60%, or
less
than about 50% by weight of polyamide-imide fibers.
[0023] The textile materials described above are believed to be well-suited
for
use in applications where the textile material must meet certain requirements
for
flame resistance. For example, the textile material can be a fabric used in
the
manufacture of curtains or window treatments, which fabric should meet the
most
stringent requirements of NFPA 701. The textile material can also be used in
the
manufacture of upholstery and furniture fabrics, automotive fabrics (e.g.,
woven, knit,
or nonwoven textiles used in automotive applications), aircraft interiors,
etc. In one
embodiment, the textile materials are formed into garments. According to one
embodiment, the garment comprises a structure comprising an internal layer,
optionally an intermediate layer made of a breathing waterproof material, and
an
outer layer made of the above-described fabric of the invention. In another
embodiment, a water and/or vapor resistant layer may be adhered to the textile
material.
[0024] The textile material described above can contain other fibers in
addition
to the polyphenylene sulfide, aramid fibers, and optional additional inherent
flame
resistant fibers discussed above. In such embodiments, the textile material
can
Date Recue/Date Received 2022-01-18
11
further comprise any suitable natural fiber or synthetic fiber or combination
of natural
fibers and/or synthetic fibers. These additional fibers can be intimately
blended with
the polyphenylene sulfide and aramid fibers within the textile material. For
example,
the textile material can be a yarn in which the polyphenylene sulfide and
aramid
fibers are intimately blended with, for example, cellulosic fibers.
Alternatively, the
additional fibers and the polyphenylene sulfide and aramid fibers can be
present in
separate elements within the textile material. For example, the textile
material can
comprise a first yarn containing the polyphenylene sulfide and aramid fibers
and a
second yarn containing, for example, cellulosic fibers.
[0025] As noted above, the textile material can comprise any suitable
natural
or synthetic fiber(s) in addition to the polyphenylene sulfide, aramid fibers,
and
optional additional inherent flame resistant fibers discussed above. In a
preferred
embodiment, the textile material further comprises cellulose fibers. The
cellulose
fibers used in such an embodiment can be natural cellulose fibers (e.g.,
cotton
fibers), regenerated cellulose fibers, or any combination thereof. Suitable
regenerated cellulose fibers include, but are not limited to, rayon fibers
(e.g., viscose
rayon fibers, high wet modulus rayon fibers, modal fibers, and polynosic
fibers),
lyocell fibers, and mixtures thereof.
[0026] When the textile material comprises cellulose fibers, the textile
material
can further comprise a flame retardant that is added to improve the flame
resistance
of the cellulose fibers and the textile material containing the same. In such
embodiments, any suitable flame retardant can be used. Preferably, the flame
retardant is a phosphorus-based flame retardant, such as the flame retardants
based
on tetrahydroxymethlphosphonium salts and condensates thereof. Suitable
examples of such flame retardants include, but are not limited to, those flame
retardants described in U.S. Patent No. 7,713,891; U.S. Patent No. 8,012,890;
U.S.
Patent No. 8,012,891; U.S. Patent No. 8,722,551; U.S. Patent No. 9,091,020;
U.S.
Patent No. 9,453,112; and U.S. Patent Application Publication No. US
2015/0118931
Al.
[0027] The textile material can also comprise synthetic fibers in addition
to the
polyphenylene sulfide, aramid fibers, and optional additional inherent flame
resistant
Date Recue/Date Received 2022-01-18
12
fibers, such as thermoplastic synthetic fibers. Suitable thermoplastic
synthetic fibers
include, but are not necessarily limited to, polyester fibers (e.g., poly
(ethylene
terephthalate) fibers, poly (propylene terephthalate) fibers, poly
(trimethylene
terephthalate) fibers), poly (butylene terephthalate) fibers, and blends
thereof),
polyamide fibers (e.g., nylon 6 fibers, nylon 6,6 fibers, nylon 4,6 fibers,
and nylon 12
fibers), polyvinyl alcohol fibers, and combinations, mixtures, or blends
thereof.
Preferably, the thermoplastic synthetic fibers are selected from the group
consisting
of polyester fibers, polypropylene fibers, and mixtures thereof.
[0028] When the textile material comprises thermoplastic synthetic fibers,
the
textile material can further comprise a flame retardant that is added to
improve the
flame resistance of the thermoplastic synthetic fibers and the textile
material
containing the same. Any flame retardant suitable for use with thermoplastic
synthetic fibers can be used in such embodiments.
[0029] In a preferred embodiment, the polyphenylene sulfide fibers and the
aramid fibers are intimately blended together and formed into yarns.
Intimately
blended means that the two types of fibers are not formed into separate yarns
and
then twisted together, but that the yarn contains both polyphenylene sulfide
fibers
and the aramid fibers entangled with each other. Preferably, the yarns are
formed
by the process of spinning, wherein the process of spinning is selected from
the
group consisting of open-end, ring, jet, vortex, rotor-spun, and Siro-spun
spinning.
Most preferred are the open-end spinning and ring spinning processes. In ring
spinning, the ring yarn has consistent fiber orientation. Most of the fibers
look to be
oriented to the same angle, so most of the fibers help contribute to the yarn
strength.
Open end spinning is an alternative to ring spinning. Unlike the fiber
orientation seen
in ring spun yarns, the fiber orientation in an open end yarn tends to be more
random
and inconsistent.
[0030] In a second embodiment, the invention provides a method for dyeing
textiles that contain polyphenylene sulfide fibers. The method generally
comprises
the steps of: (a) providing a textile material comprising polyphenylene
sulfide fibers
and aramid fibers; (b) providing a dye liquor comprising a liquid medium and a
disperse dye; (c) applying the dye liquor to the textile material; (d) heating
the textile
Date Recue/Date Received 2022-01-18
13
material under ambient atmosphere to a temperature sufficient to evaporate
substantially all of the liquid medium from the textile material; and (e)
heating the
textile material under ambient atmosphere to a temperature sufficient to fix
the
disperse dye to the polyphenylene sulfide fibers.
[0031] The textile material utilized in the method can be any suitable
textile
material comprising polyphenylene sulfide and aramid fibers, such as any of
the
textile materials described above.
[0032] As noted above, the dye liquor comprises a liquid medium and a
disperse dye. The liquid medium can be any liquid medium suitable for use with
disperse dyes. Typically, the liquid medium is an aqueous medium, such as
water.
The liquid medium can comprise a surfactant or wetting agent in order to
improve
wetting of the polyphenylene sulfide fibers with the dye liquor. In a
preferred
embodiment, the dye liquor has a pH of about 4 to about 7.5, more preferably
about
to about 7.
[0033] The disperse dye present in the dye liquor can be any of the
disperse
dyes discussed above in connection with the textile material of the invention.
In a
preferred embodiment, the dye liquor further comprises a volatile organic acid
having
a boiling point of about 100 C to about 170 C. Suitable examples of such
volatile
organic acids include, but are not limited to, acetic acid, formic acid,
propionic acid,
butyric acid, and mixtures thereof. While not wishing to be bound to any
particular
theory, it is believed that such volatile organic acids improve the color
yield of the
dyeing process, especially when the dye is fixed at temperatures of 180 C or
more.
Further, with a boiling point of 100 C to 170 C, it is believed that the
organic acid
vaporizes during the dye fixation step and does not leave any harmful residue
on the
fibers.
[0034] In a preferred embodiment, the dye liquor further comprises a dye
carrier. Suitable dye carriers include, but are not limited to, propylene
glycol,
ethylene glycol, dipropylene glycol, tripropylene glycol, diethylene glycol,
triethylene
glycol, benzoic acid, triethanolamine, polyethylene oxide, polyethylene
glycol,
copolymers of ethylene oxide and propylene oxide, and mixtures thereof. While
not
wishing to be bound to any particular theory, it is believed that such dye
carriers can
Date Recue/Date Received 2022-01-18
14
assist in dye solubilization and/or dye penetration and diffusion into the
polyphenylene sulfide fibers.
[0035] The dye liquor can be applied to the textile material in any
suitable
fashion and using any suitable apparatus. Typically, the textile material is
passed
through a bath of the dye liquor so that it is saturated with the dye liquor.
Upon
exiting the bath, the textile material can be passed through one or more nip
rollers,
which apply pressure to the textile material and remove excess dye liquor
before the
drying step. Alternatively, the dye liquor can be sprayed directly onto the
surface of
the textile material.
[0036] Following application of the dye liquor, the textile material is
heated
under ambient atmosphere to a temperature sufficient to evaporate
substantially all
of the liquid medium (and any volatile organic acid and/or dye carrier in the
dye
liquor) from the textile material. The textile material can be heated to any
suitable
temperature in this step. Preferably, the textile material is heated to a
temperature
greater than 40 C, more preferably 100 C, 130 C, or 140 C.
[0037] Following the drying step, the textile material is heated to a
temperature sufficient to fix the dye in the polyphenylene sulfide fibers.
This dye
fixation step preferably is performed under ambient atmosphere, meaning that
the
step is not performed in a closed system under elevated pressure. The textile
material can be heated to any suitable temperature in order to fix the dye.
Preferably, the textile material is heated to a temperature of 160 C or more.
More
preferably, the textile material is heated to a temperature of about 180 C or
more or
about 190 C or more. The textile material preferably is not heated to a
temperature
greater than 260 C because such temperatures have been observed to cause
adverse dye degradation. In a preferred embodiment, the textile material is
heated
to a temperature of about 180 C to about 260 C, more preferably about 190 C
to
about 240 C.
[0038] Following the dye fixation step, the textile material can be further
treated in order to remove and/or neutralize any unfixed disperse dye that
remains
on the textile material. Thus, in a preferred embodiment, the method described
above further comprises the step of treating the textile material from step
(e) with a
Date Recue/Date Received 2022-01-18
15
caustic solution to remove or neutralize unfixed disperse dye on the textile
material.
The textile material can be treated with the caustic solution in any suitable
manner.
For example, the textile material can be immersed in a bath of the caustic
solution
(maintained at a temperature of 40 C to about 80 C) for a sufficient amount
of time
to remove and/or neutralize the unfixed dye. Alternatively, the textile
material can be
impregnated with the caustic solution and then steamed. The caustic solution
preferably comprises a reducing agent that is capable of reducing any unfixed
disperse dye to an uncolored form. Suitable reducing agents include, but are
not
limited to, sodium bisulfite. Following treatment with the caustic solution as
described above, the textile material is then washed in water to remove the
dye
residues and dried.
[0039] When the textile material comprises other fibers in addition to the
polyphenylene sulfide fibers, the method described above can be modified in
order
to dye the additional fibers. For example, when the textile material comprises
cellulose fibers in addition to the polyphenylene sulfide fibers, the dye
liquor can
further comprise one or more vat dyes, which will dye the cellulose fibers.
The
method can also be preceded or succeeded by a series of steps that dye the
additional fibers. For example, when the textile material comprises polyester
fibers,
the textile material can be jet dyed using disperse dyes in order to impart
the desired
color and shade to the polyester fibers. In such an embodiment, the textile
material
can be jet dyed before or after dyeing in accordance with the method described
above. Alternatively, the polyester fibers and the polyphenylene sulfide
fibers can be
dyed simultaneously using the method described above using one or more
suitable
disperse dyes. In such an embodiment, one can select a single disperse dye
having
the appropriate properties to dye both the polyphenylene sulfide fibers and
the
polyester fibers, or one can use a mixture of disperse dyes, at least one of
which
possesses the appropriate properties (as described above) to dye the
polyphenylene
sulfide fibers.
[0040] The aramid fibers may have been dyed during manufacture of the
fibers and would not need any additional steps of dyeing once the fibers were
formed
into yarns or textile materials (unless it was desirable to dye the fibers
again).
Aramid fiber may also be used in their natural state and would need to be dyed
in a
Date Recue/Date Received 2022-01-18
16
yarn or textile if it was desired to have the aramid fibers have color. This
dyeing
process can be performed before or after the PPS fiber dyeing process.
[0041] Fabric containing meta-aramid fibers can be dyed in a piece dyeing
process where certain amount of fabric is placed into a dyeing equipment
capable of
getting the fabric in contact with a hot dyeing liquid under agitation at
elevated
temperatures (typically 70 C ¨ 150 C) in a closed system and potentially under
pressure. Typical piece dye equipment includes jet dyeing machine, beck dyeing
machine and jig dyeing machine. The dye liquid includes at least one dye, a
carrier
organic solvent, an inorganic salt, pH control agent, and water.
[0042] The dye in the dye liquid can be a disperse dye or a cationic dye.
Typically, a cationic dye is used. Various mixtures and amounts of cationic
dyes or
disperse dyes can be used to achieve desirable colors on the fabric.
[0043] A carrier organic solvent is used to help swell the meta-aramid
fiber to
facility dye diffusion into the fiber interior. Typical carrier organic
solvents include 1-
phenoxy-2-propanol, benzyl alcohol, n-methyl pyrrolidone, n-cyclohexyl 2-
pyrrolidone, N,N-diethyl-m-toluamide, N-methylformanilide, and a commercial
product called Cindye DNK marketed by Bozzetto Group. The carrier organic
solvent
can be used at an amount of 0.2 ¨ 10 g/liter of dye liquid, typically, 1-
4g/liter.
[0044] Inorganic salts, such as NaCI, NaNO3, Na2SO4, and others can be
added to the dye liquid to help improve the dyeing of meta-aramid fiber. NaNO3
is
typically used at an amount of 1 g/I to 50g/I, or typically 1g/I¨ 10g/I.
Acetic acid or
other organic acid is typically added to the dye liquid to adjust the pH of
the liquid to
a range of pH 2-5, or 2.5 ¨ 4.5. The ratio by weight of dyeing liquid to the
fabric is
typically 50:1 to 1:1. Most typically, 10:1 to 2:1.
[0045] Once the fabric is loaded into the dye equipment, and brought into
contact with the dye liquid under agitation, the dye liquid is heated up
controllably to
an elevated temperature, and held at an elevated temperature for a set amount
of
time to allow the dye(s) to diffuse into the meta-aramid fiber sufficiently.
In a typical
dyeing cycle the dye liquid may be heated at a controlled rate to 130 C, and
held at
130 C for 1 hour, then cooled down to about 50-70 C. The fabric is then rinsed
with
a hot aqueous liquid containing cleaning agents (such as surfactants and/or
redox
chemicals) to remove unfixed surface dyes on the meta-aramid fiber surface.
Date Recue/Date Received 2022-01-18
17
[0046] Additional description of dyeing meta-aramid fiber in a fabric can
be
found in US Patents 4898596, 5207803, 6867154, 3884626, 3986827, 4525168,
5306312, and 6840967.
[0047] The following examples further illustrate the subject matter
described
above but, of course, should not be construed as in any way limiting the scope
thereof.
Example 1
[0048] A woven or knit fabric can be made by using yarn made from blending
solution-dyed aramid fiber (20% - 80%) and polyphenylene sulfide (PPS) fiber
(80% -
20% by wt.). Other fibers in small amounts (preferably 2-10% wt.) including
antistatic fibers, para-aramid fibers, and polyoxadiazole (POD) fibers may
optionally
be added. The fabric is then dyed with a disperse in a continuous dyeing
process
according to the method described in the specification to dye the PPS fiber
portion of
the fabric. The dyed fabrics are expected to exhibit good flame resistance in
a
vertical flame test. The color fastness to light and washing are expected to
be
superior to piece dyed NOMEX IIIA type fabrics.
Example 2
[0049] A NOMEX IIIA blended fabric (which contained 93% NOMEX meta-
aramid material with 5% KEVLAR para-aramid and 2% antistatic fiber) was
padded
with several disperse solutions and run through a thermosol continuous dyeing
process. There was virtually no staining of the NOMEX0111A fabric by the
disperse
dyes. Accordingly, the polyphenylene sulfide fiber in the fabric can be
independently
dyed without causing problematic cross-staining issues, as evidenced by the
fact
that the aramid fiber does not dye using the PPS dyeing process.
Example 3
Date Recue/Date Received 2022-01-18
18
[0050] Similar to Example 1 except the aramid fiber is replaced by
polyamide-
imide fiber (available from KERMAL8). A wide range of solution dyed KERMAL
fiber
are commercially available and can be blended with PPS fiber.
Example 4
[0051] FR rayon fiber can be added to the fabric of Example 1 or Example 3
at
5% - 50% by weight to embody improved moisture absorption and other comfort
benefit. The dyeing process will include dye solution comprising a mixture of
disperse dyes/vat dyes, or disperse dyes/reactive dyes and the dyeing process
is
similar to continuous dyeing used for polycotton fabrics.
Example 5
[0052] The fabrics similar to what are described in Example 1 can be made
by
using natural aramid fiber (aramid fiber that has not been dyed). The PPS
fiber
portion of the fabric is first dyed with disperse dye in a process as
described in
Example 1. The fabric is subsequently dyed with cationic dyes in a batch jet
dyeing
process to dye the aramid fibers within the fabric. The disperse dyed PPS
fiber
portion is not expected to lose disperse dye in the jet or be stained by the
cationic
dyes. The dyed fabric would be expected to have a smooth and uniform color
appearance.
Date Recue/Date Received 2022-01-18
