U.S. patent application number 13/354842 was filed with the patent office on 2013-07-25 for fiber blend, spun yarn, textile material, and method for using the textile material.
The applicant listed for this patent is James D. Cliver, James Travis Greer, Shulong Li. Invention is credited to James D. Cliver, James Travis Greer, Shulong Li.
Application Number | 20130189518 13/354842 |
Document ID | / |
Family ID | 48797459 |
Filed Date | 2013-07-25 |
United States Patent
Application |
20130189518 |
Kind Code |
A1 |
Li; Shulong ; et
al. |
July 25, 2013 |
FIBER BLEND, SPUN YARN, TEXTILE MATERIAL, AND METHOD FOR USING THE
TEXTILE MATERIAL
Abstract
The invention provides a fiber blend, spun yarn, and textile
material comprising a plurality of cellulosic fibers and a
plurality of first synthetic fibers. The first synthetic fibers
comprise a polyoxadiazole polymer, and the polyoxadiazole polymer
comprises a plurality of first repeating units and a plurality of
second repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below ##STR00001## Y is
selected from the group consisting of chlorine, bromine,
diphenylphosphine oxide, and diphenylphosphine sulfide. The
invention also provides a method for protecting an individual from
infrared radiation that can be generated during an electrical arc
flash using such a textile material.
Inventors: |
Li; Shulong; (Spartanburg,
SC) ; Cliver; James D.; (Roebuck, SC) ; Greer;
James Travis; (Chesnee, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Li; Shulong
Cliver; James D.
Greer; James Travis |
Spartanburg
Roebuck
Chesnee |
SC
SC
SC |
US
US
US |
|
|
Family ID: |
48797459 |
Appl. No.: |
13/354842 |
Filed: |
January 20, 2012 |
Current U.S.
Class: |
428/373 |
Current CPC
Class: |
C08L 79/06 20130101;
D06P 3/8204 20130101; D10B 2201/20 20130101; D02G 3/443 20130101;
Y10T 428/2929 20150115; C08G 73/08 20130101 |
Class at
Publication: |
428/373 |
International
Class: |
D02G 3/00 20060101
D02G003/00 |
Claims
1. A fiber blend comprising: (a) a plurality of cellulosic fibers;
and (b) a plurality of first synthetic fibers comprising a
polyoxadiazole polymer, the polyoxadiazole polymer comprising a
plurality of first repeating units and a plurality of second
repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below ##STR00017##
wherein Y is selected from the group consisting of chlorine,
bromine, diphenylphosphine oxide, and diphenylphosphine sulfide;
wherein the cellulosic fibers and the first synthetic fibers are
intimately blended.
2. The fiber blend of claim 1, wherein the cellulosic fibers
comprise about 40 wt. % to about 80 wt. % of the fiber blend.
3. The fiber blend of claim 1, wherein Y is bromine.
4. The fiber blend of claim 1, wherein the first synthetic fibers
comprise about 10 wt. % to about 50 wt. % of the fiber blend.
5. The fiber blend of claim 1, wherein the ratio of the number of
first repeating units in the polyoxadiazole polymer to the number
of second repeating units in the polyoxadiazole polymer is from
about 5:1 to about 25:1.
6. The fiber blend of claim 5, wherein the ratio of the number of
first repeating units in the polyoxadiazole polymer to the number
of second repeating units in the polyoxadiazole polymer is from
about 9:1 to about 20:1.
7. The fiber blend of claim 1, wherein the fiber blend comprises
about 5 wt. % to about 15 wt. % of a plurality of second synthetic
fibers.
8. The fiber blend of claim 7, wherein the second synthetic fibers
are selected from the group consisting of antistatic fibers,
polyamide fibers, polyester fibers, and blends thereof.
9. The fiber blend of claim 1, wherein the fiber blend further
comprises a phosphorous-containing flame retardant.
10. A spun yarn comprising: (a) a plurality of cellulosic fibers;
and (b) a plurality of first synthetic fibers comprising a
polyoxadiazole polymer, the polyoxadiazole polymer comprising a
plurality of first repeating units and a plurality of second
repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below ##STR00018##
wherein Y is selected from the group consisting of chlorine,
bromine, diphenylphosphine oxide, and diphenylphosphine
sulfide.
11. The spun yarn of claim 10, wherein the cellulosic fibers
comprise about 40 wt. % to about 80 wt. % of the spun yarn.
12. The spun yarn of claim 10, wherein Y is bromine.
13. The spun yarn of claim 10, wherein the first synthetic fibers
comprise about 10 wt. % to about 50 wt. % of the spun yarn.
14. The spun yarn of claim 10, wherein the ratio of the number of
first repeating units in the polyoxadiazole polymer to the number
of second repeating units in the polyoxadiazole polymer is from
about 5:1 to about 25:1.
15. The spun yarn of claim 14, wherein the ratio of the number of
first repeating units in the polyoxadiazole polymer to the number
of second repeating units in the polyoxadiazole polymer is from
about 9:1 to about 20:1.
16. The spun yarn of claim 10, wherein the spun yarn comprises
about 5 wt. % to about 15 wt. % of a plurality of second synthetic
fibers.
17. The spun yarn of claim 16, wherein the second synthetic fibers
are selected from the group consisting of antistatic fibers,
polyamide fibers, polyester fibers, and blends thereof.
18. The spun yarn of claim 10, wherein the spun yarn further
comprises a phosphorous-containing flame retardant.
19. The spun yarn of claim 10, wherein the spun yarn further
comprises a vat dye, and the vat dye is deposited on both the
cellulosic fibers and the first synthetic fibers.
20. A textile material comprising: (a) a plurality of cellulosic
fibers; and (b) a plurality of first synthetic fibers comprising a
polyoxadiazole polymer, the polyoxadiazole polymer comprising a
plurality of first repeating units and a plurality of second
repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below ##STR00019##
wherein Y is selected from the group consisting of chlorine,
bromine, diphenylphosphine oxide, and diphenylphosphine
sulfide.
21. The textile material of claim 20, wherein the cellulosic fibers
comprise about 40 wt. % to about 80 wt. % of the textile
material.
22. The textile material of claim 20, wherein Y is bromine.
23. The textile material of claim 20, wherein the first synthetic
fibers comprise about 10 wt. % to about 50 wt. % of the textile
material.
24. The textile material of claim 20, wherein the ratio of the
number of first repeating units in the polyoxadiazole polymer to
the number of second repeating units in the polyoxadiazole polymer
is from about 5:1 to about 25:1.
25. The textile material of claim 24, wherein the ratio of the
number of first repeating units in the polyoxadiazole polymer to
the number of second repeating units in the polyoxadiazole polymer
is from about 9:1 to about 20:1.
26. The textile material of claim 20, wherein the textile material
comprises about 5 wt. % to about 15 wt. % of a plurality of second
synthetic fibers.
27. The textile material of claim 26, wherein the second synthetic
fibers are selected from the group consisting of antistatic fibers,
polyamide fibers, polyester fibers, and blends thereof.
28. The textile material of claim 20, wherein the textile material
further comprises a phosphorous-containing flame retardant.
29. The textile material of claim 20, wherein the textile material
further comprises a vat dye, and the vat dye is deposited on both
the cellulosic fibers and the first synthetic fibers.
30. A method for protecting an individual from infrared radiation
that can be generated during an arc flash, the method comprising
the step of positioning a textile material between an individual
and an apparatus capable of producing an arc flash, the textile
material comprising: (a) a plurality of cellulosic fibers; and (b)
a plurality of first synthetic fibers comprising a polyoxadiazole
polymer, the polyoxadiazole polymer comprising a plurality of first
repeating units and a plurality of second repeating units, the
first repeating units conforming to the structure of Formula (I)
below and the second repeating units conforming to the structure of
Formula (II) below ##STR00020## wherein Y is selected from the
group consisting of chlorine, bromine, diphenylphosphine oxide, and
diphenylphosphine sulfide.
31. The method of claim 30, wherein the textile material is part of
a garment worn by the individual.
32. The method of claim 30, wherein the cellulosic fibers comprise
about 40 wt. % to about 80 wt. % of the textile material.
33. The method of claim 30, wherein Y is bromine.
34. The method of claim 30, wherein the first synthetic fibers
comprise about 10 wt. % to about 50 wt. % of the textile
material.
35. The method of claim 30, wherein the ratio of the number of
first repeating units in the polyoxadiazole polymer to the number
of second repeating units in the polyoxadiazole polymer is from
about 5:1 to about 25:1.
36. The method of claim 35, wherein the ratio of the number of
first repeating units in the polyoxadiazole polymer to the number
of second repeating units in the polyoxadiazole polymer is from
about 9:1 to about 20:1.
37. The method of claim 30, wherein the textile material comprises
about 5 wt. % to about 15 wt. % of a plurality of second synthetic
fibers.
38. The method of claim 37, wherein the second synthetic fibers are
selected from the group consisting of antistatic fibers, polyamide
fibers, polyester fibers, and blends thereof.
39. The method of claim 30, wherein the textile material further
comprises a phosphorous-containing flame retardant.
40. The method of claim 20, wherein the textile material further
comprises a vat dye, and the vat dye is deposited on both the
cellulosic fibers and the first synthetic fibers.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The invention relates to fiber blends, spun yarns comprising
such fiber blends, textile materials comprising the fibers blends
and/or spun yarns, and methods for using such textile
materials.
BACKGROUND
[0002] Flame resistant fabrics are useful in many applications,
including the production of garments worn by personnel in a variety
of industries or occupations, such as the military, electrical (for
arc protection), petroleum chemical manufacturing, and emergency
response fields. Cellulosic or cellulosic-blend fabrics have
typically been preferred for these garments, due to the relative
ease with which these fabrics may be made flame resistant and the
relative comfort of such fabrics to the wearer.
[0003] Notwithstanding the popularity of cellulosic or
cellulosic-blend flame resistant fabrics, existing fabrics do
suffer from limitations. The flammability performance of many
cellulosic flame resistant fabrics is not sufficient to meet the
demanding requirements of certain industries. In order to meet
these requirements, inherent flame resistant fibers (e.g.,
meta-aramid fibers, such as NOMEX.RTM. fiber from E. I. du Pont de
Nemours and Company) are often employed, which increases the cost
of the fabrics. Accordingly, a need remains to provide alternative
flame resistant fabrics that are capable of meeting applicable
flame resistance standards at lower cost.
BRIEF SUMMARY OF THE INVENTION
[0004] In a first embodiment, the invention provides a fiber blend
comprising:
[0005] (a) a plurality of cellulosic fibers; and
[0006] (b) a plurality of first synthetic fibers comprising a
polyoxadiazole polymer, the polyoxadiazole polymer comprising a
plurality of first repeating units and a plurality of second
repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below
##STR00002## [0007] wherein Y is selected from the group consisting
of chlorine, bromine, diphenylphosphine oxide, and
diphenylphosphine sulfide; and
[0008] wherein the cellulosic fibers and the first synthetic fibers
are intimately blended.
[0009] In a second embodiment, the invention provides a spun yarn
comprising:
[0010] (a) a plurality of cellulosic fibers; and
[0011] (b) a plurality of first synthetic fibers comprising a
polyoxadiazole polymer, the polyoxadiazole polymer comprising a
plurality of first repeating units and a plurality of second
repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below
##STR00003## [0012] wherein Y is selected from the group consisting
of chlorine, bromine, diphenylphosphine oxide, and
diphenylphosphine sulfide.
[0013] In a third embodiment, the invention provides a textile
material comprising:
[0014] (a) a plurality of cellulosic fibers; and
[0015] (b) a plurality of first synthetic fibers comprising a
polyoxadiazole polymer, the polyoxadiazole polymer comprising a
plurality of first repeating units and a plurality of second
repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below
##STR00004## [0016] wherein Y is selected from the group consisting
of chlorine, bromine, diphenylphosphine oxide, and
diphenylphosphine sulfide.
[0017] In a fourth embodiment, the invention provides a method for
protecting an individual from infrared radiation that can be
generated during an arc flash, the method comprising the step of
positioning a textile material between an individual and an
apparatus capable of producing an arc flash, the textile material
comprising:
[0018] (a) a plurality of cellulosic fibers; and
[0019] (b) a plurality of first synthetic fibers comprising a
polyoxadiazole polymer, the polyoxadiazole polymer comprising a
plurality of first repeating units and a plurality of second
repeating units, the first repeating units conforming to the
structure of Formula (I) below and the second repeating units
conforming to the structure of Formula (II) below
##STR00005## [0020] wherein Y is selected from the group consisting
of chlorine, bromine, diphenylphosphine oxide, and
diphenylphosphine sulfide.
DETAILED DESCRIPTION OF THE INVENTION
[0021] In a first embodiment, the invention provides a fiber blend
comprising a plurality of cellulosic fibers and a plurality of
first synthetic fibers, the first synthetic fibers comprising a
polyoxadiazole polymer. The fibers in the fiber blend preferably
are intimately blended so that each different fiber type is
substantially evenly distributed throughout the fiber blend.
[0022] As noted above, the fiber blend of the invention comprises
cellulosic fibers. As utilized herein, the term "cellulosic fibers"
is used to refer to fibers composed of, or derived from, cellulose.
Examples of suitable cellulosic fibers include cotton, rayon,
linen, jute, hemp, cellulose acetate, and combinations, mixtures,
or blends thereof. Suitable types of rayon include flame retardant
rayon (FR rayon), which is a rayon fiber having a flame retardant
compound (e.g., an organophosphorous compound) incorporated
therein. FR rayon is available from many sources, such as Lenzing
AG. Preferably, the cellulosic fibers comprise cotton fibers. The
cotton fibers can, as discussed below, be treated with a
phosphorous-containing flame retardant.
[0023] In those embodiments comprising cotton fibers, the cotton
fibers can be of any suitable variety. Generally, there are two
varieties of cotton fibers that are readily available for
commercial use in North America: the American Upland variety
(Gossypium hirsutum) and the American Pima variety (Gossypium
barbadense). The cotton fibers used as the cellulosic fibers in the
invention can be cotton fibers of either the American Upland
variety, the American Pima variety, or a combination, mixture, or
blend of the two. Generally, cotton fibers of the American Upland
variety, which comprise the majority of the cotton used in the
apparel industry, have lengths ranging from about 0.875 inches to
about 1.3 inches, while the less common fibers of the American Pima
variety have lengths ranging from about 1.2 inches to about 1.6
inches. Preferably, at least some of the cotton fibers used in the
invention are of the American Pima variety, which are preferred due
to their greater, more uniform length.
[0024] The cellulosic fibers can be present in the fiber blend in
any suitable amount. For example, the cellulosic fibers preferably
can comprise about 25 wt. % or more, about 30 wt. % or more, about
35 wt. % or more, or about 40 wt. % or more of the fibers present
in the fiber blend. The cellulosic fibers preferably can comprise
about 90 wt. % or less, about 85 wt. % or less, about 80 wt. % or
less, about 75 wt. % or less, about 70 wt. % or less, about 65 wt.
% or less, or about 60 wt. % or less of the fibers present in the
fiber blend. Thus, in a preferred embodiment, the cellulosic fibers
comprise about 25 wt. % to about 90 wt. % (e.g., about 30 wt. % to
about 90 wt. %, about 35 wt. % to about 90 wt. %, or about 40 wt. %
to about 90 wt. %), about 25 wt. % to about 85 wt. % (e.g., about
30 wt. % to about 85 wt. %, about 35 wt. % to about 85 wt. %, or
about 40 wt. % to about 85 wt. %), about 25 wt. % to about 80 wt. %
(e.g., about 30 wt. % to about 80 wt. %, about 35 wt. % to about 80
wt. %, or about 40 wt. % to about 80 wt. %), about 25 wt. % to
about 75 wt. % (e.g., about 30 wt. % to about 75 wt. %, about 35
wt. % to about 75 wt. %, or about 40 wt. % to about 75 wt. %),
about 25 wt. % to about 70 wt. % (e.g., about 30 wt. % to about 70
wt. %, about 35 wt. % to about 70 wt. %, or about 40 wt. % to about
70 wt. %), about 25 wt. % to about 65 wt. % (e.g., about 30 wt. %
to about 65 wt. %, about 35 wt. % to about 65 wt. %, or about 40
wt. % to about 65 wt. %), or about 25 wt. % to about 60 wt. %
(e.g., about 30 wt. % to about 60 wt. %, about 35 wt. % to about 60
wt. %, or about 40 wt. % to about 60 wt. %) of the fibers present
in the fiber blend. In a particularly preferred embodiment, the
cellulosic fibers can comprise about 40 wt. % to about 60 wt. % of
the fibers present in the fiber blend.
[0025] The fiber blend comprises a plurality of first synthetic
fibers, and the first synthetic fibers comprise a polyoxadiazole
polymer. As will be understood by those of skill in the art, the
term "oxadiazole" refers to five-membered, heterocyclic, aromatic
groups containing an oxygen atom, two nitrogen atoms, and two
carbon atoms, in which at least one of nitrogen atoms is separated
from the oxygen atom by a carbon atom. Thus, there are two possible
oxadiazole groups: a 1,3,4-oxadiazole group, which has the
structure
##STR00006##
and a 1,2,4-oxadiazole group, which has the structure
##STR00007##
Thus, a polyoxadiazole polymer can comprise a 1,3,4-oxadiazole
group, a 1,2,4-oxadiazole group, or a mixture of the two. The
polymer in the polyoxadiazole fibers can contain any other suitable
repeating group or unit, with arylene groups being particularly
preferred. In a preferred embodiment, the first synthetic fibers
comprise a polyoxadiazole polymer that comprises a plurality of
first repeating units and a plurality of second repeating units.
The first repeating units in the polyoxadiazole polymer conform to
the structure of Formula (I) below
##STR00008##
The second repeating units in the polyoxadiazole polymer conform to
the structure of Formula (II) below
##STR00009##
In the structure of Formula (II), Y can be any suitable group.
Preferably, Y is selected from the group consisting of chlorine,
bromine, diphenylphosphine oxide, and diphenylphosphine sulfide. In
a particularly preferred embodiment, Y is bromine.
[0026] The polyoxadiazole polymer can comprise any suitable amounts
(e.g., relative amounts) of the first repeating units and the
second repeating units. Generally, the number of the first
repeating units in the polyoxadiazole polymer is greater than the
number of the second repeating units in the polyoxadiazole polymer.
For example, the ratio of the number of first repeating units in
the polyoxadiazole polymer to the number of second repeating units
in the polyoxadiazole polymer can be about 5:1 or more, about 6:1
or more, about 7:1 or more, about 8:1 or more, or about 9:1 or
more. The ratio of the number of first repeating units in the
polyoxadiazole polymer to the number of second repeating units in
the polyoxadiazole polymer can be about 25:1 or less, about 24:1 or
less, about 23:1 or less, about 22:1 or less, about 21:1 or less,
or about 20:1 or less. Thus, in a preferred embodiment, the ratio
of the number of first repeating units in the polyoxadiazole
polymer to the number of second repeating units in the
polyoxadiazole polymer is about 5:1 to about 25:1 (e.g., about 6:1
to about 25:1, about 7:1 to about 25:1, about 8:1 to about 25:1, or
about 9:1 to about 25:1), about 5:1 to about 24:1 (e.g., about 6:1
to about 24:1, about 7:1 to about 24:1, about 8:1 to about 24:1, or
about 9:1 to about 24:1), about 5:1 to about 23:1 (e.g., about 6:1
to about 23:1, about 7:1 to about 23:1, about 8:1 to about 23:1, or
about 9:1 to about 23:1), about 5:1 to about 22:1 (e.g., about 6:1
to about 22:1, about 7:1 to about 22:1, about 8:1 to about 22:1, or
about 9:1 to about 22:1), about 5:1 to about 21:1 (e.g., about 6:1
to about 21:1, about 7:1 to about 21:1, about 8:1 to about 21:1, or
about 9:1 to about 21:1), or about 5:1 to about 20:1 (e.g., about
6:1 to about 20:1, about 7:1 to about 20:1, about 8:1 to about
20:1, or about 9:1 to about 20:1). In one preferred embodiment, the
ratio of the number of first repeating units in the polyoxadiazole
polymer to the number of second repeating units in the
polyoxadiazole polymer is from about 5:1 to about 25:1. In another
preferred embodiment, the ratio of the number of first repeating
units in the polyoxadiazole polymer to the number of second
repeating units in the polyoxadiazole polymer is from about 9:1 to
about 20:1.
[0027] While not wishing to be bound to any particular theory, it
is believed that the presence of the first synthetic fibers (which
comprise a polyoxadiazole polymer as described above) will impart
at least some flame resistant properties to the fiber blend and any
materials (e.g., spun yarns or fabrics) made therefrom. It is
believed that these flame resistant properties are attributable, at
least in part, to the relatively high heat stability of the
polyoxadiazole polymer. Indeed, it is believed that the particular
polyoxadiazole polymer described above (i.e., the polyoxadiazole
polymer containing the first repeating units and second repeating
units described above) exhibits a more desirable combination of
properties (including flame resistance) than other polyoxadiazole
polymers (i.e., polyoxadiazole polymers that do not comprise the
described combination of repeating units). Thus, as discussed
below, it is believed that the fiber blend of the invention and
materials made therefrom (e.g., spun yarns and fabrics) are
particularly well-suited for use in making flame resistant
garments, apparel, and protective equipment.
[0028] The first synthetic fibers can be present in the fiber blend
in any suitable amount. For example, the first synthetic fibers
preferably can comprise about 5 wt. % or more, about 6 wt. % or
more, about 7 wt. % or more, about 8 wt. % or more, about 9 wt. %
or more, or about 10 wt. % or more of the fiber blend. The first
synthetic fibers preferably can comprise about 60 wt. % or less,
about 55 wt. % or less, or about 50 wt. % or less of the fiber
blend. Thus, in a preferred embodiment, the first synthetic fibers
can comprise about 5 wt. % to about 60 wt. % (e.g., about 6 wt. %
to about 60 wt. %, about 7 wt. % to about 60 wt. %, about 8 wt. %
to about 60 wt. %, about 9 wt. % to about 60 wt. %, or about 10 wt.
% to about 60 wt. %), about 5 wt. % to about 55 wt. % (e.g., about
6 wt. % to about 55 wt. %, about 7 wt. % to about 55 wt. %, about 8
wt. % to about 55 wt. %, about 9 wt. % to about 55 wt. %, or about
10 wt. % to about 55 wt. %), or about 5 wt. % to about 50 wt. %
(e.g., about 6 wt. % to about 50 wt. %, about 7 wt. % to about 50
wt. %, about 8 wt. % to about 50 wt. %, about 9 wt. % to about 50
wt. %, or about 10 wt. % to about 50 wt. %) of the fiber blend.
[0029] The fiber blend can comprise other fibers in addition to the
cellulosic fibers and the first synthetic fibers. If present, these
additional fibers can be either natural fibers or synthetic fibers.
Suitable synthetic fibers include, but are not limited to,
antistatic fibers (e.g., electrostatic dissipative fibers),
thermoplastic synthetic fibers, and inherent flame resistant
fibers. Suitable antistatic or electrostatic dissipative fibers
include, but are not limited to, carbon fibers, such as P140
antistatic carbon fibers from DuPont. The antistatic or
electrostatic dissipative fibers can be present in the fiber blend
in any suitable amount. For example, the antistatic or
electrostatic dissipative fibers can comprise about 1 wt. % to
about 5 wt. % (e.g., about 1 wt. % to about 3 wt. %, or about 2 wt.
%) of the fiber blend. The antistatic fibers have been found to be
effective at mitigating electrostatic buildup that can occur in the
process of blending the fibers and also imparting antistatic
properties to the yarns and textile materials (e.g., fabrics) made
from the fiber blend.
[0030] Thermoplastic synthetic fibers can be included in the fiber
blend to increase the durability of textile materials (e.g., yarns
and fabrics) to, for example, industrial washing conditions. In
particular, thermoplastic synthetic fibers tend to be rather
durable to abrasion and harsh washing conditions employed in
industrial laundry facilities and their inclusion in, for example,
a spun yarn can increase that yarns durability to such conditions.
This increased durability of the yarn, in turn, leads to an
increased durability for a textile material made from that yarn.
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.
[0031] In those embodiments in which the fiber blend comprises
thermoplastic synthetic fibers, the thermoplastic synthetic fibers
can be present in the fiber blend in any suitable amount. For
example, the thermoplastic synthetic fibers can comprise about 1
wt. % or more, about 2 wt. % or more, about 3 wt. % or more, about
4 wt. % or more, or about 5 wt. % or more of the blend. The
thermoplastic synthetic fibers can comprise about 50 wt. % or less,
about 45 wt. % or less, about 40 wt. % or less, about 35 wt. % or
less, about 30 wt. % or less, about 25 wt. % or less, about 20 wt.
% or less, or about 15 wt. % or less of the fiber blend. Thus, in a
preferred embodiment, the thermoplastic synthetic fibers can
comprise about 1 wt. % to about 50 wt. % (e.g., about 1 wt. % to
about 45 wt. %, about 1 wt. % to about 40 wt. %, about 1 wt. % to
about 35 wt. %, about 1 wt. % to about 30 wt. %, about 1 wt. % to
about 25 wt. %, about 1 wt. % to about 20 wt. % or about 1 wt. % to
about 15 wt. %), about 2 wt. % to about 50 wt. % (e.g., about 2 wt.
% to about 45 wt. %, about 2 wt. % to about 40 wt. %, about 2 wt. %
to about 35 wt. %, about 2 wt. % to about 30 wt. %, about 2 wt. %
to about 25 wt. %, about 2 wt. % to about 20 wt. % or about 2 wt. %
to about 15 wt. %), about 3 wt. % to about 50 wt. % (e.g., about 3
wt. % to about 45 wt. %, about 3 wt. % to about 40 wt. %, about 3
wt. % to about 35 wt. %, about 3 wt. % to about 30 wt. %, about 3
wt. % to about 25 wt. %, about 3 wt. % to about 20 wt. % or about 3
wt. % to about 15 wt. %), about 4 wt. % to about 50 wt. % (e.g.,
about 4 wt. % to about 45 wt. %, about 4 wt. % to about 40 wt. %,
about 4 wt. % to about 35 wt. %, about 4 wt. % to about 30 wt. %,
about 4 wt. % to about 25 wt. %, about 4 wt. % to about 20 wt. % or
about 4 wt. % to about 15 wt. %), or about 5 wt. % to about 50 wt.
% (e.g., about 5 wt. % to about 45 wt. %, about 5 wt. % to about 40
wt. %, about 5 wt. % to about 35 wt. %, about 5 wt. % to about 30
wt. %, about 5 wt. % to about 25 wt. %, about 5 wt. % to about 20
wt. % or about 5 wt. % to about 15 wt. %) of the fiber blend. In
one particularly preferred embodiment, the thermoplastic synthetic
fibers comprise about 5 wt. % to about 15 wt. % of the fiber
blend.
[0032] As noted above, the fiber blend can comprise inherent flame
resistant fibers in addition to the cellulosic fibers and the first
synthetic fibers. As utilized herein, the term "inherent flame
resistant fibers" is used to refer 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 such embodiments, the inherent flame
resistant fibers can be any suitable inherent flame resistant
fibers, such as polyoxadiazole fibers (i.e., polyoxadiazole fibers
comprising a polyoxadiazole polymer that is different from the
polyoxadiazole polymer of the first synthetic fibers),
polysulfonamide fibers, poly(benzimidazole) fibers,
poly(phenylenesulfide) fibers, meta-aramid fibers, para-aramid
fibers, polypyridobisimidazole fibers, polybenzylthiazole fibers,
polybenzyloxazole fibers, melamine-formaldehyde polymer fibers,
phenol-formaldehyde polymer fibers, oxidized polyacrylonitrile
fibers, partially-oxidized polyacrylonitrile fibers, modacrylic
fibers, polyamide-imide fibers and combinations, mixtures, or
blends thereof. In certain embodiments, the inherent flame
resistant fibers are preferably selected from the group consisting
of polyoxadiazole fibers, polysulfonamide fibers,
poly(benzimidazole) fibers, poly(phenylenesulfide) fibers,
meta-aramid fibers, para-aramid fibers, and combinations, mixtures,
or blends thereof. In a more specific embodiment, the inherent
flame resistant fibers can be selected from the group consisting of
polyoxadiazole fibers, polysulfonamide fibers, poly(benzimidazole)
fibers, poly(phenylenesulfide) fibers, and combinations, mixtures,
or blends thereof.
[0033] The inherent flame resistant fibers can be present in the
fiber blend in any suitable amount. For example, the inherent flame
resistant fibers can comprise about 1 wt. % or more, about 2 wt. %
or more, about 3 wt. % or more, about 4 wt. % or more, or about 5
wt. % or more of the fiber blend. The inherent flame resistant
fibers can comprise about 40 wt. % or less, about 35 wt. % or less,
about 30 wt. % or less, about 25 wt. % or less, about 20 wt. % or
less, about 15 wt. % or less, or about 10 wt. % or less of the
fiber blend. For example, in one preferred embodiment, the fiber
blend can further comprise about 5 wt. % to about 10 wt. % of a
para-aramid fiber, which is believed to improve the mechanical
strength of the spun yarns and textile materials (e.g., fabrics)
made from the fiber blend without compromising (and possibly even
improving) the flame resistance of the materials.
[0034] The fiber blend of the invention can be used to create a
variety of textile materials. For example, the fiber blend can be
used alone or in conjunction with other fibers to create nonwoven
textile materials. The fiber blend can also be used to produce a
spun yarn. Thus, in a second embodiment, the invention provides a
spun yarn made from the fiber blend described above. In particular,
the invention provides a spun yarn comprising a plurality of
cellulosic fibers and a plurality of first synthetic fibers, the
first synthetic fibers comprising a polyoxadiazole polymer. Since
the spun yarn is made using the fiber blend of the invention, the
cellulosic fibers, the first synthetic fibers, and, if present, the
additional fibers can be any of those described above in connection
with the fiber blend of the invention and such fibers can be
present in the spun yarn in any of the amounts described above in
connection with the fiber blend of the invention.
[0035] The spun yarn of the invention can be made by any suitable
spinning process. For example, the spun yarns can be formed by a
ring spinning process, an air-jet spinning process, or an open-end
spinning process. In certain embodiments, the yarns are spun using
a ring spinning process (i.e., the yarns are ring spun yarns).
[0036] The fiber blend of the invention and the spun yarn of the
invention can each be used to create textile materials. For
example, the spun yarn can be used alone or in conjunction with
other yarns to produce knit textile materials (e.g., knit fabrics)
or woven textile materials (e.g., woven fabrics). Thus, in a third
embodiment, the invention provides a textile material comprising a
plurality of cellulosic fibers and a plurality of first synthetic
fibers, the first synthetic fibers comprising a polyoxadiazole
polymer. Since the textile material is made using the fiber blend
of the invention or the spun yarn of the invention, the cellulosic
fibers, the first synthetic fibers, and, if present, the additional
fibers can be any of those described above in connection with the
fiber blend of the invention and such fibers can be present in the
textile material in any of the amounts described above in
connection with the fiber blend of the invention.
[0037] As noted above, the textile materials of the invention can
be made using the spun yarns of the invention in conjunction with
other yarns. In such an embodiment, these additional yarns can be
any suitable type of yarn, such as monofilament yarns,
multifilament yarns, spun yarns, and combinations of such yarns,
and the yarns can comprise any suitable type of fiber, such as
natural fibers, synthetic fibers, and combinations of the two. For
example, the textile material can be formed using a first plurality
of spun yarns according to the invention and a second plurality of
spun yarns comprising, for example, cellulosic fibers alone or in
combination with thermoplastic synthetic fibers. As explained
below, in such an embodiment, the yarns can be disposed in a
patternwise arrangement that results in one of the yarns being
predominantly disposed on one surface of the textile material and
the other yarn being predominantly disposed on the opposite surface
of the textile material. With such an arrangement, the textile
material can be made in such a way as to place the spun yarns of
the invention, which will exhibit flame resistant properties due to
the present of the first synthetic fibers, on a surface of the
textile material where such flame resistant properties can provide
the most benefit when the textile material is worn.
[0038] The textile materials of the invention can be of any
suitable construction. In other words, the yarns forming the
textile material can be provided in any suitable patternwise
arrangement producing a fabric. Preferably, the textile materials
are provided in a woven construction, such as a plain weave, basket
weave, twill weave, satin weave, or sateen weave. Suitable plain
weaves include, but are not limited to, ripstop weaves produced by
incorporating, at regular intervals, extra yarns or reinforcement
yarns in the warp, fill, or both the warp and fill of the textile
material during formation. Suitable twill weaves include both
warp-faced and fill-faced twill weaves, such as 2/1, 3/1, 3/2, 4/1,
1/2, 1/3, or 1/4 twill weaves. In certain embodiments of the
invention, such as when the textile material is formed from two or
more pluralities or different types of yarns, the yarns are
disposed in a patternwise arrangement in which one of the yarns is
predominantly disposed on one surface of the textile material. In
other words, one surface of the textile material is predominantly
formed by one yarn type. Suitable patternwise arrangements or
constructions that provide such a textile material include, but are
not limited to, satin weaves, sateen weaves, and twill weaves in
which, on a single surface of the fabric, the fill yarn floats and
the warp yarn floats are of different lengths.
[0039] In one series of embodiments, the invention provides textile
materials made from the spun yarns described above, and those
textile materials can be flame resistant. As utilized herein, the
term "flame resistant" refers to a material that burns slowly or is
self-extinguishing after removal of an external source of ignition.
The flame resistance of textile materials can be measured by any
suitable test method, such as those described in National Fire
Protection Association (NFPA) 701 entitled "Standard Methods of
Fire Tests for Flame Propagation of Textiles and Films," ASTM D6413
entitled "Standard Test Method for Flame Resistance of Textiles
(vertical test)", NFPA 2112 entitled "Standard on Flame Resistant
Garments for Protection of Industrial Personnel Against Flash
Fire", ASTM F1506 entitled "The Standard Performance Specification
for Flame Resistant Textile Materials for Wearing Apparel for Use
by Electrical Workers Exposed to Momentary Electric Arc and Related
Thermal Hazards", and ASTM F1930 entitled "Standard Test Method for
Evaluation of Flame Resistant Clothing for Protection Against Flash
Fire Simulations Using an Instrumented Manikin."
[0040] The textile material according to the invention can be
treated with one or more flame retardant treatments or finishes to
render the textile materials more flame resistant. Typically, such
flame retardant treatments or finishes are applied to a textile
material containing cellulosic fibers in order to impart flame
resistant properties to the cellulosic portion of the textile
material. In such embodiments, the flame retardant treatment or
finish can be any suitable treatment. Suitable treatments include,
but are not limited to, halogenated flame retardants (e.g.,
brominated or chlorinated flame retardants), phosphorous-based
flame retardants, antimony-based flame retardants,
nitrogen-containing flame retardants, and combinations, mixtures,
or blends thereof.
[0041] In one preferred embodiment, the textile material of the
invention is treated with a phosphorous-based flame retardant
treatment. In this embodiment, a tetrahydroxymethyl phosphonium
salt, a condensate of a tetrahydroxymethyl phosphonium salt, or a
mixture thereof is first applied to the textile material. As
utilized herein, the term "tetrahydroxymethyl phosphonium salt"
refers to salts containing the tetrahydroxymethyl phosphonium (THP)
cation, which has the structure
##STR00010##
including, but not limited to, the chloride, sulfate, acetate,
carbonate, borate, and phosphate salts. As utilized herein, the
term "condensate of a tetrahydroxymethyl phosphonium salt" (THP
condensate) refers to the product obtained by reacting a
tetrahydroxymethyl phosphonium salt, such as those described above,
with a limited amount of a cross-linking agent, such as urea,
guanazole, or biguanide, to produce a compound in which at least
some of the individual tetrahydroxymethyl phosphonium cations have
been linked through their hydroxymethyl groups. The structure for
such a condensate produced using urea is set forth below
##STR00011##
The synthesis of such condensates is described, for example, in
Frank et al. (Textile Research Journal, November 1982, pages
678-693) and Frank et al. (Textile Research Journal, December 1982,
pages 738-750). These THPS condensates are also commercially
available, for example, as PYROSAN.RTM. CFR from Emerald
Performance Materials.
[0042] The THP or THP condensate can be applied to the textile
material in any suitable amount. Typically, the THP salt or THP
condensate is applied to the textile material in an amount that
provides at least 0.5% (e.g., at least 1%, at least 1.5%, at least
2%, at least 2.5%, at least 3%, at least 3.5%, at least 4%, or at
least 4.5%) of elemental phosphorus based on the weight of the
untreated textile material. The THP salt or THP condensate is also
typically applied to the textile in an amount that provides less
than 5% (e.g., less than 4.5%, less than 4%, less than 3.5%, less
than 3%, less than 2.5%, less than 2%, less than 1.5%, or less than
1%) of elemental phosphorus based on the weight of the untreated
textile material. Preferably, the THP salt or THP condensate is
applied to the textile material in an amount that provides about 1%
to about 4% (e.g., about 1% to about 3% or about 1% to about 2%) of
elemental phosphorous based on the weight of the untreated textile
material.
[0043] Once the THP salt or THP condensate has been applied to the
textile material, the THP salt or THP condensate is then reacted
with a cross-linking agent. The product produced by this reaction
is a cross-linked phosphorus-containing flame retardant polymer.
The cross-linking agent is any suitable compound that enables the
cross-linking and/or curing of THP. Suitable cross-linking agents
include, for example, urea, a guanidine (i.e., guanidine, a salt
thereof, or a guanidine derivative), guanyl urea, glycoluril,
ammonia, an ammonia-formaldehyde adduct, an ammonia-acetaldehyde
adduct, an ammonia-butyraldehyde adduct, an ammonia-chloral adduct,
glucosamine, a polyamine (e.g., polyethyleneimine, polyvinylamine,
polyetherimine, polyethyleneamine, polyacrylamide, chitosan,
aminopolysaccharides), glycidyl ethers, isocyanates, blocked
isocyanates and combinations thereof. Preferably, the cross-linking
agent is urea or ammonia, with urea being the more preferred
cross-linking agent.
[0044] The cross-linking agent can be applied to the textile
material in any suitable amount. The suitable amount of
cross-linking agent varies based on the weight of the textile
material and its construction. Typically, the cross-linking agent
is applied to the textile material in an amount of at least 0.1%
(e.g., at least 1%, at least 2%, at least 3%, at least 4%, at least
5%, at least 7%, at least 10%, at least 15%, at least 18%, or at
least 20%) based on the weight of the untreated textile material.
The cross-linking agent is also typically applied to the textile
material in an amount of less than 25% (e.g., less than 20%, less
than 18%, less than 15%, less than 12%, less than 10%, less than
7%, less than 5%, less than 3%, or less than 1%) based on the
weight of the untreated textile material. In a potentially
preferred embodiment, the cross-linking agent is applied to the
textile material in an amount of about 4% to about 12% based on the
weight of the untreated textile material. In another potentially
preferred embodiment, the cross-linking agent is applied to the
textile material in an amount of about 2% to about 7% based on the
weight of the untreated textile material.
[0045] In order to accelerate the condensation reaction of the THP
salt or THP condensate and the cross-linking agent, the
above-described reaction can be carried out at elevated
temperatures. The time and elevated temperatures used in this
curing step can be any suitable combinations of times and
temperatures that result in the reaction of the THP or THP
condensate and cross-linking agent to the desired degree. The time
and elevated temperatures used in this curing step can also promote
the formation of covalent bonds between the cellulosic fibers and
the phosphorous-containing condensation product, which is believed
to contribute to the durability of the flame retardant treatment.
However, care must be taken not to use excessively high
temperatures or excessively long cure times that might result in
excessive reaction of the flame retardant with the cellulosic
fibers, which might weaken the cellulosic fibers and the textile
material. Furthermore, it is believed that the elevated
temperatures used in the curing step can allow the THP salt or THP
condensate and cross-linking agent to diffuse into the cellulosic
fibers where they react to form a cross-linked
phosphorus-containing flame retardant polymer within the fibers.
Suitable temperatures and times for this curing step will vary
depending upon the curing oven used and the speed with which heat
is transferred to the textile material, but suitable conditions can
range from temperatures of about 149.degree. C. (300.degree. F.) to
about 177.degree. C. (350.degree. F.) and times from about 1 minute
to about 3 minutes.
[0046] In the case where ammonia is used as the cross-linking
agent, it is not necessary to use elevated temperatures for the THP
salt or THP condensate and cross-linking agent to react. In such
case, the reaction can be carried out, for example, in a gas-phase
ammonia chamber at ambient temperature. A suitable process for
generating a phosphorous-based flame retardant using this
ammonia-based process is described, for example, in U.S. Pat. No.
3,900,664 (Miller), the disclosure of which is hereby incorporated
by reference.
[0047] After the THP salt or THP condensate and cross-linking agent
have been cured and allowed to react to the desired degree, the
resulting textile material can be exposed to an oxidizing agent.
While not wishing to be bound to any particular theory, it is
believed that this oxidizing step converts the phosphorous in the
condensation product (i.e., the condensation product produced by
the reaction of the THP salt or THP condensate and cross-linking
agent) from a trivalent form to a more stable pentavalent form. The
resulting phosphorous-containing compound (i.e., cross-linked,
phosphorous-containing flame retardant polymer) is believed to
contain a plurality of pentavalent phosphine oxide groups. In those
embodiments in which urea has been used to cross-link the THP salt
or THP condensate, the phosphorous-containing compound comprises
amide linking groups covalently bonded to the pentavalent phosphine
oxide groups, and it is believed that at least a portion of the
phosphine oxide groups have three amide linking groups covalently
bonded thereto.
[0048] The oxidizing agent used in this step can be any suitable
oxidant, such as hydrogen peroxide, sodium perborate, or sodium
hypochlorite. The amount of oxidant can vary depending on the
actual materials used, but typically the oxidizing agent is
incorporated in a solution containing at least 0.1% concentration
(e.g., at least 0.5%, at least 0.8, at least 1%, at least 2%, or at
least 3% concentration) and less than 20% concentration (e.g., less
than 15%, less than 12%, less than 10%, less than 3%, less than 2%,
or less than 1% concentration) of the oxidant.
[0049] After contacting the treated textile material with the
oxidizing agent, the cured textile material preferably is contacted
with a neutralizing solution (e.g., a caustic solution with a pH of
at least 8, at least pH 9, at least pH 10, at least pH 11, or at
least pH 12). The actual components of the caustic solution can
widely vary, but suitable components include any strong base, such
as alkalis. For example, sodium hydroxide (soda), potassium
hydroxide (potash), calcium oxide (lime), or any combination
thereof can be used in the neutralizing solution. The amount of
base depends on the size of the bath and is determined by the
ultimately desired pH level. A suitable amount of caustic in the
solution is at least 0.1% concentration (e.g., at least 0.5%, at
least 0.8%, at least 1%, at least 2%, or at least 3% concentration)
and is less than 10% concentration (e.g., less than 8%, less than
6%, less than 5%, less than 3%, less than 2%, or less than 1%
concentration). The contact time of the treated textile material
with the caustic solution varies, but typically is at least 30
seconds (e.g., at least 1 min, at least 3 min, at least 5 min, or
at least 10 min). If desired, the neutralizing solution can be
warmed (e.g., up to 75.degree. C., up to 70.degree. C., up to
60.degree. C., up to 50.degree. C., up to 40.degree. C., up to
30.degree. C. relative to room temperature).
[0050] In another preferred embodiment, the textile material of the
invention is treated with a different phosphorous-containing flame
retardant compound. In this embodiment, at least a portion of the
textile material is contacted with a treatment composition to
deposit the treatment composition thereon. The treatment
composition comprises a precondensate compound and a cross-linking
composition. The textile material is then heated to a temperature
sufficient for the precondensate compound and the cross-linking
composition to react in a condensation reaction and produce a
phosphorous-containing intermediate polymer. Then, at least a
portion of the textile material having the phosphorous-containing
intermediate polymer thereon is exposed to an oxidizing agent under
conditions sufficient to convert at least a portion of the
phosphorous atoms in the phosphorous-containing intermediate
polymer to a pentavalent state. The resulting
phosphorous-containing polymer exhibits flame resistant properties
and imparts those properties to the cellulosic fibers in the
textile material.
[0051] The treatment composition comprises a precondensate compound
and a cross-linking composition. The precondensate compound is
produced by the condensation reaction of a reactant mixture
comprising a phosphonium compound and a nitrogen-containing
compound.
[0052] The reactant mixture can comprise any suitable phosphonium
compound. As utilized herein, the term "phosphonium compound"
refers to a compound containing a phosphonium cation, which is a
positively charged substituted phosphine. The phosphonium compound
can comprise a phosphonium cation substituted with any suitable
substituents, such as alkyl, haloalkyl, alkenyl, and haloalkenyl
groups, all of which can be substituted with at least one hydroxyl
group. In a preferred embodiment, the reactant mixture comprises at
least one phosphonium compound conforming to the structure of
Formula (X)
##STR00012##
[0053] In the structure of Formula (X), R.sub.1 can be any suitable
group, such as an alkyl group, a haloalkyl group, an alkenyl group,
or a haloalkenyl group. In a preferred embodiment, R.sub.1 is
selected from the group consisting of hydrogen, C.sub.1-C.sub.3
alkyl, C.sub.1-C.sub.3 haloalkyl, C.sub.2-C.sub.3 alkenyl, and
C.sub.2-C.sub.3 haloalkenyl. In another preferred embodiment,
R.sub.1 can be hydrogen. In the structure of Formula (X), X
represents an anion and can be any suitable monatomic or polyatomic
anion. In a preferred embodiment, X can be an anion selected from
the group consisting of halides (e.g., chloride), sulfate, hydrogen
sulfate, phosphate, acetate, carbonate, bicarbonate, borate, and
hydroxide. In another preferred embodiment, X is a sulfate anion.
In the structure of Formula (X), b represents the charge of the
anion X. Therefore, in order to provide a phosphonium compound that
is charge neutral, the number of phosphonium cations present in the
compound is equal to (-b). Examples of phosphonium compounds that
are suitable for use in the reactant mixture include, but are not
limited to, tetrahydroxymethyl phosphonium salts, such as
tetrahydroxymethyl phosphonium chloride, tetrahydroxymethyl
phosphonium sulfate, tetrahydroxymethyl phosphonium acetate,
tetrahydroxymethyl phosphonium carbonate, tetrahydroxymethyl
phosphonium borate, and tetrahydroxymethyl phosphonium phosphate.
The reactant mixture can comprise one phosphonium compound, or the
reactant mixture can comprise a mixture of two or more phosphonium
compounds.
[0054] The reactant mixture can comprise any suitable
nitrogen-containing compound or combination of nitrogen-containing
compounds. In a preferred embodiment, the reactant mixture
comprises at least one nitrogen-containing compound conforming to
the structure of Formula (XI)
##STR00013##
In the structure of Formula (XI), R.sub.2, R.sub.3, R.sub.4,
R.sub.5, R.sub.6, and R.sub.7 can be any suitable groups. In a
preferred embodiment, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6,
and R.sub.7 are independently selected from the group consisting of
hydrogen, hydroxymethyl, and alkoxymethyl. Suitable
nitrogen-containing compounds include, but are not limited to,
melamine, methylolated melamines, and alkoxymethyl melamines (e.g.,
etherified methylol melamines). The reactant mixture can comprise
one nitrogen-containing compound, or the reactant mixture can
comprise a mixture of two or more nitrogen-containing
compounds.
[0055] The reactant mixture can contain any suitable amounts of the
phosphonium compound and the nitrogen-containing compound. The
amounts of the phosphonium compound and the nitrogen-containing
compound in the reactant mixture can be expressed through a molar
ratio of the two components in the reactant mixture. However, as
will be understood by those skilled in the art (and as illustrated
below), it is the phosphonium cation(s) in the phosphonium compound
that participate in the reaction between the phosphonium compound
and the nitrogen-containing compound. (The phosphonium compound's
counterion is simply there to balance the charge.) Thus, in order
to accurately express the relative amount of each reactive
component present in the reactant mixture, the molar amount of the
phosphonium compound present in the reactant mixture should be
normalized to express the number of reactive phosphonium cations
contributed to the reactant mixture by the phosphonium compound.
This can be simply done by taking the number of moles of the
phosphonium compound present in the reactant mixture and
multiplying this value by the number of phosphonium cations present
in a molecule of the phosphonium compound. For example, if the
reactant mixture contains one mole of a phosphonium compound
containing two phosphonium cations per molecule (e.g.,
tetrahydroxymethyl phosphonium sulfate), then the reactant mixture
will contain two moles of reactive phosphonium cations ([1 mole of
tetrahydroxymethyl phosphonium sulfate].times.[2 phosphonium
cations per molecule of tetrahydroxymethyl phosphonium sulfate]=2
moles of phosphonium cations). If two or more phosphonium compounds
are present in the reactant mixture, then this calculation must be
separately performed for each phosphonium compound. The results
from each calculation can then be added to arrive at the total
number of moles of reactive phosphonium cations present in the
reactant mixture. The FIGURE representing the number of moles of
phosphonium cations present in the reactant mixture and the molar
amount of the nitrogen-containing compound can then be used to
express the relative amounts of the phosphonium compound and the
nitrogen-containing compound in the reactant mixture (e.g., a molar
ratio of phosphonium cations to nitrogen-containing compound), as
discussed below.
[0056] Preferably, the phosphonium compound and the
nitrogen-containing compound are present in the reactant mixture in
an initial molar ratio of phosphonium cations to
nitrogen-containing compound of about 50:1 or less, about 40:1 or
less, about 30:1 or less, about 25:1 or less, about 20:1 or less,
about 15:1 or less, about 10:1 or less, or about 8:1 or less. The
phosphonium compound and the nitrogen-containing compound
preferably are present in the reactant mixture in an initial molar
ratio of phosphonium cations to nitrogen-containing compound of
about 3:1 or more or about 6:1 or more. In a preferred embodiment,
the phosphonium compound and the nitrogen-containing compound are
present in the reactant mixture in an initial molar ratio of
phosphonium cations to nitrogen-containing compound of about 50:1
to about 3:1. In another preferred embodiment, the phosphonium
compound and the nitrogen-containing compound are present in the
reactant mixture in an initial molar ratio of phosphonium cations
to nitrogen-containing compound of about 40:1 to about 3:1, about
30:1 to about 3:1, about 25:1 to about 3:1, about 20:1 to about
3:1, about 15:1 to about 3:1 (e.g., about 15:1 to about 6:1), about
10:1 to about 3:1, or about 8:1 to about 3:1 (e.g., about 6:1).
[0057] The reactant mixture can contain other components in
addition to the phosphonium compound and the nitrogen-containing
compound described above. For example, the reactant mixture can
contain other nitrogenous compounds, such as urea, guanazole,
biguanide, or alkylene ureas. While these other nitrogenous
compounds can be present in the reactant mixture, they are
typically present in a relatively small amount as compared to the
amount of the nitrogen-containing compound present in the reactant
mixture. The reactant mixture can also contain a surfactant, such
as an alkoxylated alcohol, which aids in the dispersion of the
nitrogen-containing compound as described below. The reactant
mixture can also contain one or more pH buffers, such as acetate
salts (e.g., sodium acetate), phosphate salts (e.g., alkaline metal
phosphate salts), tertiary amines, and amino alcohols.
[0058] The components of the reactant mixture can be reacted under
any suitable conditions which result in a condensation reaction
between the phosphonium compound and the nitrogen-containing
compound. In one possible embodiment, the phosphonium compound is
provided in the form of an aqueous solution and the
nitrogen-containing compound (e.g., melamine) is provided in the
form of a solid or a solid dispersed in a liquid medium. Generally,
in order to facilitate the reaction between the phosphonium
compound and the nitrogen-containing compound, the
nitrogen-containing compound is provided in the form of a solid
(e.g., powder) having relatively small particle size, such as an
average particle size of about 100 .mu.m or less. In this
embodiment, the nitrogen-containing compound is added to the
aqueous solution of the phosphonium compound while the solution is
vigorously agitated. In order to further facilitate the
incorporation of the nitrogen-containing compound in the solution,
a surfactant can be added. Any suitable surfactant can be used,
such as an alkoxylated alcohol. Once the nitrogen-containing
compound is added to the solution, the resulting reactant mixture
is heated to a temperature sufficient to effect a condensation
reaction between the phosphonium compound and the
nitrogen-containing compound. In a preferred embodiment, the
reactant mixture is heated to a temperature of about 60.degree. C.
to about 90.degree. C. and maintained within this temperature range
for a sufficient amount of time for the phosphonium compound and
the nitrogen-containing compound to react, such as about 2 hours to
about 8 hours. Generally, the phosphonium compound is provided in a
molar excess relative to the amount of the nitrogen-containing
compound, and the reactant mixture is maintained at the elevated
temperature for a sufficient amount of time for the
nitrogen-containing compound to be completely consumed by the
condensation reaction. Since the precondensate compound formed by
the reaction of the phosphonium compound and the
nitrogen-containing compound is water-soluble, the complete
consumption of the nitrogen-containing compound can be visually
confirmed by the absence of solid particles of the
nitrogen-containing compound in the reactant mixture.
[0059] Although the exact chemical structure of the precondensate
compound has not been determined, the structure of Formula (XII)
below depicts one example of a precondensate compound that is
believed to be formed by the condensation reaction described
above.
##STR00014##
The precondensate compound depicted in the structure of Formula
(XII) can be produced by reacting a tetrahydroxymethyl phosphonium
salt with melamine. For the sake of simplicity, the counterions
balancing the overall positive charge of the molecule have not been
depicted. As it is depicted in the structure of Formula (XII), the
phosphonium compound (i.e., tetrahydroxymethyl phosphonium salt)
was present in a sufficient amount to replace each of the six amine
hydrogens present on the melamine. With such an excess of the
phosphonium compound present in the reactant mixture, the resulting
precondensate compound may also contain oligomers (e.g., dimers,
trimers, etc.) in which two or more melamine "cores" have been
cross-linked by phosphonium compound molecules. Furthermore, when
an excess of the phosphonium compound is used, the condensation
reaction may produce a precondensate compound that is contained
within a composition comprising a significant amount of unreacted
phosphonium compound, such as about 1% to about 50% excess
phosphonium compound.
[0060] In addition to the precondensate compound described above,
the treatment composition comprises a cross-linking composition.
The cross-linking composition can comprise any suitable
cross-linking compound. Preferably, the cross-linking compound
comprises two nitrogen-containing functional groups that are
capable of reacting with the hydroxyl-bearing carbon atoms of the
precondensate compound. (These hydroxyl-bearing carbon atoms are
those from the phosphonium compound that did not react with the
nitrogen-containing compound when the precondensate compound was
formed. An exemplary compound containing such hydroxyl-bearing
carbon atoms is depicted in the structure of Formula (XII) above.)
Furthermore, each of these reactive nitrogen-containing functional
groups preferably has only one hydrogen atom directly bonded to the
nitrogen atom. Thus, when such a cross-linking compound reacts with
the precondensate compound, the nitrogen-containing functional
groups forming the cross-links will no longer have any hydrogen
atoms directly bonded to the nitrogen atom of the functional group.
While not wishing to be bound to any particular theory, it is
believed that such a cross-link (i.e., a cross-link in which the
nitrogen atom does not have a hydrogen atom bonded thereto) is less
susceptible to oxidative attack (e.g., attack by oxidative
chlorine) than a cross-link in which the nitrogen atom still bears
a hydrogen atom. This reduced susceptibility to oxidative attack is
believed to contribute, at least in part, to the improved wash
durability of the flame retardant composition of the invention.
[0061] The cross-linking composition can comprise any suitable
cross-linking compound possessing the characteristics described
above. In a preferred embodiment, the cross-linking composition
comprises an alkylene urea compound (e.g., a cyclic alkylene urea
compound). In a preferred embodiment, the cross-linking composition
comprises an alkylene urea compound selected from the group
consisting of ethylene urea, propylene urea, and mixtures
thereof.
[0062] The cross-linking composition can contain other compounds in
addition to the alkylene urea compound mentioned above. For
example, the cross-linking composition can contain additional
cross-linking agents (i.e., cross-linking agents in addition to the
alkylene urea compound). Cross-linking agents suitable for such use
include, for example, urea, a guanidine (i.e., guanidine, a salt
thereof, or a guanidine derivative, such as cyanoguanidine), guanyl
urea, glycoluril, ammonia, an ammonia-formaldehyde adduct, an
ammonia-acetaldehyde adduct, an ammonia-butyraldehyde adduct, an
ammonia-chloral adduct, glucosamine, a polyamine (e.g.,
polyethyleneimine, polyvinylamine, polyetherimine,
polyethyleneamine, polyacrylamide, chitosan, aminopolysaccharides),
glycidyl ethers, isocyanates, blocked isocyanates and combinations
thereof. While these other cross-linking agents can be present in
the cross-linking composition, they typically are present in a
relatively small amount as compared to the amount of the primary
cross-linking compound (e.g., alkylene urea) present in the
cross-linking composition.
[0063] The precondensate compound and the cross-linking composition
can be present in the treatment composition in any suitable amounts
that permits a condensation reaction between the two. The amounts
of the two components in the treatment composition can be expressed
in terms of the initial weight ratio of the two components. In a
preferred embodiment, the precondensate compound and the
cross-linking composition are present in the treatment composition
in an initial weight ratio of about 1:2 or more, about 1:1 or more,
about 3:2 or more, about 2:1 or more, or about 3:1 or more. In
another preferred embodiment, the precondensate compound and the
cross-linking composition are present in the treatment composition
in an initial weight ratio of precondensate compound to
cross-linking composition of about 10:1 or less, about 9:1 or less,
about 8:1 or less, about 7:1 or less, about 6:1 or less, about 5:1
or less, about 4:1 or less, or about 3:1 or less. Thus, in certain
preferred embodiments, the precondensate compound and the
cross-linking composition are present in the treatment composition
in an initial weight ratio of precondensate compound to
cross-linking composition of about 1:2 to about 10:1 (e.g., about
1:2 to about 5:1), about 1:1 to about 10:1 (e.g., about 1:1 to
about 8:1, about 1:1 to about 6:1, about 1:1 to about 5:1, or about
1:1 to about 4:1), about 3:2 to about 10:1 (e.g., about 3:2 to
about 8:1, about 3:2 to about 4:1), or about 2:1 to about 10:1
(e.g., about 2:1 to about 8:1, about 2:1 to about 6:1, about 2:1 to
about 5:1, about 2:1 to about 4:1, or about 2:1 to about 3:1).
[0064] As noted above, the cross-linking composition can contain
more than one distinct compound. For the purposes of calculating
the ratios described in the preceding paragraph, the amount of the
cross-linking composition will be the amount (by weight) of the
component(s) in the cross-linking composition that are capable of
reacting with the precondensate compound in a condensation
reaction. Thus, when the cross-linking composition contains only
one compound that is capable of reacting with the precondensate
compound (e.g., an alkylene urea), then the amount used in
calculating the above-described ratios will be the amount (by
weight) of this compound (e.g., the alkylene urea) present in the
cross-linking composition. And, if the cross-linking composition
contains more than one compound that is capable of reacting with
the precondensate compound, the amount used for the purposes of
calculating the ratios described in the preceding paragraph will be
the total amount (by weight) of "reactive" compounds present in the
cross-linking composition. This value is simply the sum of the
weight of each "reactive" compound present in the present in the
cross-linking composition. In either case, solvents, carriers, and
other non-reactive components present in the cross-linking
composition are not factored into the calculated ratios described
in the preceding paragraph.
[0065] The precondensate compound and the cross-linking composition
can be provided in any suitable form(s). For example, the
precondensate compound can be provided in the form of an aqueous
solution, dispersion or suspension. Typically, the precondensate
compound is provided in the form of an aqueous solution. In such an
embodiment, the cross-linking composition can be provided in the
form of a solid that is added to the aqueous solution, or the
cross-linking composition can be provided in the form of a solution
or dispersion that is mixed with the aqueous solution.
[0066] The treatment composition can be applied to the textile
material in any suitable amount. One suitable means for expressing
the amount of treatment composition that is applied to the textile
material is specifying the amount of elemental phosphorous that is
added as a percentage of the weight of the untreated textile
material (i.e., the textile material prior to the application of
the treatment composition described herein). This percentage can be
calculated by taking the weight of elemental phosphorous added,
dividing this value by the weight of the untreated textile
material, and multiplying by 100%. Typically, the treatment
composition is applied to the textile material in an amount that
provides about 0.5% or more (e.g., about 1% or more, about 1.5% or
more, about 2% or more, about 2.5% or more, about 3% or more, about
3.5% or more, about 4% or more, or about 4.5% or more) of elemental
phosphorus based on the weight of the untreated textile material.
The treatment composition is also typically applied to the textile
material in an amount that provides about 5% or less (e.g., about
4.5% or less, about 4% or less, about 3.5% or less, about 3% or
less, about 2.5% or less, about 2% or less, about 1.5% or less, or
about 1% or less) of elemental phosphorus based on the weight of
the untreated textile material. Preferably, the treatment
composition is applied to the textile material in an amount that
provides about 1% to about 4% (e.g., about 1% to about 3% or about
1% to about 2%) of elemental phosphorous based on the weight of the
untreated textile material.
[0067] The textile material can be contacted with the treatment
composition using any suitable technique, such as any of the wet
processing techniques commonly used to treat textile materials. For
example, the textile substrate can be contacted with the treatment
composition by padding, foaming, or jet "dyeing" (i.e., treating
the textile substrate in a jet dyeing machine containing the
treatment composition instead of or in addition to a dye
liquor).
[0068] In order to accelerate the condensation reaction between the
precondensate compound and the cross-linking composition, the
treated textile material typically is heated to a temperature
sufficient for the precondensate compound and the cross-linking
composition to react and produce a phosphorous-containing
intermediate polymer on the textile material. The time and elevated
temperature used in this step can be any suitable combination of
time and temperature that results in the reaction of the
precondensate compound and cross-linking composition to the desired
degree. When the textile material comprises cellulosic fibers, the
time and elevated temperatures used in this step can also promote
the formation of covalent bonds between the cellulosic fibers and
the phosphorous-containing intermediate polymer produced by the
condensation reaction, which is believed to contribute to the
durability of the flame retardant treatment. However, care must be
taken not to use excessively high temperatures or excessively long
cure times that might result in excessive reaction of the
phosphorous-containing intermediate polymer with the cellulosic
fibers, which might weaken the cellulosic fibers and the textile
material. Furthermore, it is believed that the elevated
temperatures used in the curing step can allow the precondensate
compound and cross-linking composition to diffuse into the
cellulosic fibers where they then react to form the
phosphorus-containing intermediate polymer within the cellulosic
fibers. Suitable temperatures and times for this step will vary
depending upon the oven used and the speed with which heat is
transferred to the textile material, but suitable conditions can
range from temperatures of about 149.degree. C. (300.degree. F.) to
about 177.degree. C. (350.degree. F.) and times from about 1 minute
to about 3 minutes.
[0069] The reaction of the precondensate compound and the
cross-linking composition results in a phosphorous-containing
intermediate polymer. Since the phosphorous-containing intermediate
polymer was produced from a precondensate compound containing
phosphonium cations, the intermediate polymer will contain
quaternary phosphorous atoms. The structure depicted in Formula
(XIII) below shows one possible structure for a segment of a
polymer produced by the reaction of ethylene urea with a
precondensate compound, which precondensate compound has been made
by reacting a tetrahydroxymethyl phosphonium salt and melamine.
##STR00015##
While such a polymer (i.e., a polymer containing quaternary
phosphorous atoms) is relatively stable, it is believed that the
stability and, for example, wash durability of the polymer can be
increased by converting at least a portion of the phosphorous atoms
in the polymer into a pentavalent state. The structure depicted in
Formula (XIV) below shows the segment depicted in Formula (XIII)
after the phosphorous atoms have been converted into a pentavalent
state.
##STR00016##
As can be seen from the structure depicted above, the conversion of
a phosphorous atom from a quaternary state to a pentavalent
involves an oxidation that converts the quaternary phosphonium
group into a phosphine oxide group. This conversion (i.e.,
oxidation of the quaternary phosphonium groups to a pentavalent
state) can be effected by reacting the phosphorous-containing
intermediate polymer with a suitable oxidizing agent. Suitable
oxidizing agents include, but are not limited to, oxygen (e.g.,
gaseous oxygen), hydrogen peroxide, sodium perborate, sodium
hypochlorite, percarbonate (e.g., alkaline metal percarbonates),
ozone, peracetic acid, and mixtures or combinations thereof.
Suitable oxidizing agents also include compounds that are capable
of generating hydrogen peroxide or peroxide species, which
compounds can be used alone or in combination with any of the
oxidizing agents listed above. As noted above, the phosphorous
containing intermediate polymer is exposed to the oxidizing agent
for a period of time and under conditions sufficient for at least a
portion of the phosphorous atoms in the intermediate polymer to be
converted to a pentavalent state. In a preferred embodiment, the
phosphorous containing intermediate polymer is exposed to the
oxidizing agent for a period of time and under conditions
sufficient to convert substantially all of the phosphorous atoms in
the intermediate polymer to a pentavalent state.
[0070] After the treatment composition has been applied to the
textile material and the components of the treatment composition
have been allowed to react in the above-described condensation
reaction, the resulting textile material can be exposed to an
oxidizing agent in order to convert at least a portion of the
phosphorous atoms in the phosphorous-containing intermediate
polymer into a pentavalent state. The mechanism of and reasons for
this conversion have been described above. Furthermore, oxidizing
agents suitable for use in this step have also been described
above, and each of these oxidizing agents (or any suitable
combination thereof) can be used in this step of treating the
textile material.
[0071] The textile material can be exposed to the oxidizing agent
using any suitable technique. For example, the textile material can
be exposed to the oxidizing agent using any of the wet processing
techniques commonly used to treat textile materials, such as those
described above in connection with the application of the treatment
composition to the textile material. The amount of oxidizing agent
used in treating the textile material can vary depending on the
actual materials used, but typically the oxidizing agent is
incorporated in a solution containing about 0.1% or more (e.g.,
about 0.5% or more, about 0.8% or more, about 1% or more, about 2%
or more, or about 3% or more) and about 20% or less (e.g., about
15% or less, about 12% or less, about 10% or less, about 3% or
less, about 2% or less, or about 1% or less), by weight, of the
oxidizing agent.
[0072] After contacting the textile material with the oxidizing
agent, the treated textile material can be contacted with a
neutralizing solution (e.g., a caustic solution with a pH of about
8 or more, about 9 or more, about 10 or more, about 11 or more, or
about 12 or more). The actual components of the caustic solution
can widely vary, but suitable components include any strong base,
such as alkalis. For example, sodium hydroxide (soda), potassium
hydroxide (potash), calcium oxide (lime), or any combination
thereof can be used in the neutralizing solution. The amount of
base depends on the size of the bath and is determined by the
ultimately desired pH level. A suitable amount of caustic in the
solution is about 0.1% or more (e.g., about 0.5% or more, about
0.8% or more, about 1% or more, about 2% or more, or about 3% or
more) and is about 10% or less (e.g., about 8% or less, about 6% or
less, about 5% or less, about 3% or less, about 2% or less, or
about 1% or less). The contact time of the treated textile material
with the caustic solution varies, but typically is about 30 seconds
or more (e.g., about 1 min or more, about 3 min or more, about 5
min or more, or about 10 min or more). If desired, the neutralizing
solution can be warmed (e.g., up to about 75.degree. C. greater, up
to about 70.degree. C. greater, up to about 60.degree. C. greater,
up to about 50.degree. C. greater, up to about 40.degree. C.
greater, or up to about 30.degree. C. greater than the ambient
temperature).
[0073] After the treated textile material has been contacted with
the oxidizing agent as described above and, if desired, contacted
with a neutralizing solution as described above, the treated
textile material typically is rinsed to remove any unreacted
components from the treatment composition, any residual oxidizing
agent, and (if the neutralization step was performed) any residual
components from the neutralizing solution. The treated textile
material can be rinsed in any suitable medium, provided the medium
does not degrade the phosphorous-containing polymer. Typically, the
treated textile material is rinsed in water (e.g., running water)
until the pH of the water is relatively neutral, such as a pH of
about 6 to about 8, or about 7. After rinsing, the treated textile
material is dried using suitable textile drying conditions.
[0074] If desired, the textile material can be treated with one or
more softening agents (also known as "softeners") to improve the
hand of the treated textile material. The softening agent selected
for this purpose should not have a deleterious effect on the
flammability of the resultant fabric. Suitable softeners include
polyolefins, alkoxylated alcohols (e.g., ethoxylated alcohols),
alkoxylated ester oils (e.g., ethoxylated ester oils), alkoxylated
fatty amines (e.g., ethoxylated tallow amine), alkyl glycerides,
alkylamines, quaternary alkylamines, halogenated waxes, halogenated
esters, silicone compounds, and mixtures thereof. In a preferred
embodiment, the softener is selected from the group consisting of
cationic softeners and nonionic softeners.
[0075] The softener can be present in the textile material in any
suitable amount. One suitable means for expressing the amount of
treatment composition that is applied to the textile material is
specifying the amount of softener that is applied to the textile
material as a percentage of the weight of the untreated textile
material (i.e., the textile material prior to the application of
the treatment composition described herein). This percentage can be
calculated by taking the weight of softener solids applied,
dividing this value by the weight of the untreated textile
material, and multiplying by 100%. Preferably, the softener is
present in the textile material in an amount of about 0.1% or more,
about 0.2% or more, or about 0.3% or more, by weight, based on the
weight of the untreated textile material. Preferably, the softener
is present in the textile material in an amount of about 10% or
less, about 9% or less, about 8% or less, about 7% or less, about
6% or less, or about 5% or less, by weight, based on the weight of
the untreated textile material. Thus, in certain preferred
embodiments, the softener is present in the textile material in an
amount of about 0.1% to about 10%, about 0.2% to about 9% (e.g.,
about 0.2% to about 8%, about 0.2% to about 7%, about 0.2% to about
6%, or about 0.2% to about 5%), or about 0.3% to about 8% (e.g.,
about 0.3% to about 7%, about 0.3% to about 6%, or about 0.3% to
about 5%), by weight, based on the weight of the untreated textile
material.
[0076] To further enhance the textile material's hand, the textile
material can optionally be treated using one or more mechanical
surface treatments. A mechanical surface treatment typically
relaxes stress imparted to the fabric during curing and fabric
handling, breaks up yarn bundles stiffened during curing, and
increases the tear strength of the treated fabric. Examples of
suitable mechanical surface treatments include treatment with
high-pressure streams of air or water (such as those described in
U.S. Pat. No. 4,918,795, U.S. Pat. No. 5,033,143, and U.S. Pat. No.
6,546,605), treatment with steam jets, needling, particle
bombardment, ice-blasting, tumbling, stone-washing, constricting
through a jet orifice, and treatment with mechanical vibration,
sharp bending, shear, or compression. A sanforizing process may be
used instead of, or in addition to, one or more of the above
processes to improve the fabric's hand and to control the fabric's
shrinkage. Additional mechanical treatments that may be used to
impart softness to the treated fabric, and which may also be
followed by a sanforizing process, include napping, napping with
diamond-coated napping wire, gritless sanding, patterned sanding
against an embossed surface, shot-peening, sand-blasting, brushing,
impregnated brush rolls, ultrasonic agitation, sueding, engraved or
patterned roll abrasion, and impacting against or with another
material, such as the same or a different fabric, abrasive
substrates, steel wool, diamond grit rolls, tungsten carbide rolls,
etched or scarred rolls, or sandpaper rolls.
[0077] The textile material of the invention can be used alone or
in conjunction with other textile materials to produce garments and
other forms of protective apparel (e.g., vests, aprons, hoods,
gloves, and chaps). Given the flame resistant properties imparted
to the textile material by the inclusion of the first synthetic
fibers, it is believed that the textile material of the invention
is particularly well-suited for use in producing apparel that is
used to protect the wearer from injury caused by exposure to fire
or intense infrared radiation.
[0078] In a fourth embodiment, the invention provides a method for
protecting an individual from infrared radiation that can be
generated during an electrical arc flash. In this embodiment, the
method comprises the step of positioning a textile material between
an individual and an apparatus capable of producing an electrical
arc flash. The textile material preferably is a textile material
according to the invention, such as any embodiment of the textile
material described above.
[0079] In this method embodiment of the invention, the textile
material can be positioned at any suitable point between the
individual and the apparatus. However, in order to ensure that the
textile material is positioned to afford the greatest degree of
protection to the individual, the textile material preferably forms
part of a garment worn by the individual. Suitable garments
include, but are not limited to, shirts, pants, coats, hoods,
aprons, and gloves. In a preferred embodiment, the outward-facing
textile portions of a garment worn by the individual (i.e., those
portions of the garment facing towards the apparatus when the
garment is being worn by the individual) consist essentially of (or
even more preferably consist of) a textile material according to
the invention.
[0080] The method described above can be used to protect an
individual from an arc flash produced by any apparatus. Typically,
the apparatus is a piece of electrical equipment. Preferably, the
apparatus is capable of producing an arc flash having an incident
energy of about 1.2 calories/cm.sup.2 or more (about 5 J/cm.sup.2
or more) at a position at which the individual is located. More
preferably, the apparatus is capable of producing an arc flash
having an incident energy of about 4 calories/cm.sup.2 or more
(about 17 J/cm.sup.2 or more) at a position at which the individual
is located. The apparatus preferably is capable of producing an arc
flash having an incident energy of about 8 calories/cm.sup.2 or
more (about 33 J/cm.sup.2 or more) at a position at which the
individual is located. An arc flash having an incident energy such
as those described above (especially an arc flash having an
incident energy of about 4 calories/cm.sup.2 or more or about 8
calories/cm.sup.2 or more) is capable of inflicting significant
injury (e.g., second degree burns) to the unprotected or
under-protected skin of an individual exposed to the arc flash.
[0081] The materials of the invention (e.g., fiber blend, spun
yarn, textile material of the invention) can be dyed to impart a
desired shade to the material. The materials of the invention can
be dyed using any suitable colorant or combination of colorants,
such as pigments, dyes, and combinations thereof. For example, the
first synthetic fibers can be dyed using cationic (basic) dyes.
Applicants have found that vat dyes are particularly useful in
dyeing the materials of the invention. While not wishing to be
bound to any particular theory, it is believed that vat dyes are
particularly useful because the vat dyes are capable of dyeing both
the cellulosic fibers and the first synthetic fibers, which
comprise the polyoxadiazole polymer. This is surprising because vat
dyes typically are not used to dye synthetic fibers. While the vat
dyes can be used and will result in dyeing of both the cellulosic
fibers and the first synthetic fibers, the first synthetic fibers
require a higher-than-expected amount of the vat dye(s) in order to
produce the desired shade (i.e., the amount of vat dye(s) required
to dye the first synthetic fibers a desired shade is greater than
the amount required to dye a similar amount of a different fiber
[e.g., cotton fiber] the same desired shade). In fact, Applicants
have found that the amount of vat dye(s) needed to dye a given
amount of the first synthetic fibers typically is about twice the
amount needed to dye the same amount of cotton fibers. Thus, when a
material (e.g., fiber blend, spun yarn, or textile material) of the
invention is dyed using a vat dye, the amount of vat dye(s) used
should be increased accordingly, which increased amount will depend
upon the amount of the first synthetic fibers present in the
material. Applicants have also found that, by dyeing the material
with vat dyes, the resulting color exhibits improved colorfastness
to light exposure, and the material is stabilized against
degradation by ultraviolet light. As noted above, the materials of
the invention can be dyed with other dyes, such as disperse dyes.
Typically, these dyes are used in combination with vat dyes when
the material contains other synthetic fibers, such as thermoplastic
synthetic fibers (e.g., polyester fibers or polyamide fibers).
[0082] All references, including publications, patent applications,
and patents, cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0083] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the subject matter of this
application (especially in the context of the following claims) are
to be construed to cover both the singular and the plural, unless
otherwise indicated herein or clearly contradicted by context. The
terms "comprising," "having," "including," and "containing" are to
be construed as open-ended terms (i.e., meaning "including, but not
limited to,") unless otherwise noted. Recitation of ranges of
values herein are merely intended to serve as a shorthand method of
referring individually to each separate value falling within the
range, unless otherwise indicated herein, and each separate value
is incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the subject matter of the
application and does not pose a limitation on the scope of the
subject matter unless otherwise claimed. No language in the
specification should be construed as indicating any non-claimed
element as essential to the practice of the subject matter
described herein.
[0084] Preferred embodiments of the subject matter of this
application are described herein, including the best mode known to
the inventors for carrying out the claimed subject matter.
Variations of those preferred embodiments may become apparent to
those of ordinary skill in the art upon reading the foregoing
description. The inventors expect skilled artisans to employ such
variations as appropriate, and the inventors intend for the subject
matter described herein to be practiced otherwise than as
specifically described herein. Accordingly, this disclosure
includes all modifications and equivalents of the subject matter
recited in the claims appended hereto as permitted by applicable
law. Moreover, any combination of the above-described elements in
all possible variations thereof is encompassed by the present
disclosure unless otherwise indicated herein or otherwise clearly
contradicted by context.
* * * * *