WO2006034131A2

WO2006034131A2 - Flame resistant fabrics and garments having the appearance of denim

Info

Publication number: WO2006034131A2
Application number: PCT/US2005/033371
Authority: WO
Inventors: D. Craig Tutterow
Original assignee: Southern Mills, Inc.
Priority date: 2004-09-21
Filing date: 2005-09-20
Publication date: 2006-03-30
Also published as: CA2580817A1; US20060059634A1; WO2006034131A3

Abstract

Disclosed are flame resistant fabrics and garments having the appearance of denim. In one embodiment, a piece-dyed, flame resistant fabric includes first flame resistant yarns that extend along the fabric in a first direction and second flame resistant yarns that extend along the fabric in a second that is different from the first direction so as to interweave the second flame resistant yarns with the first flame resistant yarns, wherein the first flame resistant yarns are dyed due to the piece dyeing and the second flame resistant yams are substantially undyed to create the denim appearance.

Description

FLAME RESISTANT FABRICS AND GARMENTS HAVING THE APPEARANCE OF DENIM

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to copending U.S. utility patent application entitled "FLAME RESISTANT FABRICS AND GARMENTS HAVING THE APPEARANCE OF DENIM" filed on September 21, 2004 and accorded serial number 10/946,415, which is entirely incorporated herein by reference.

BACKGROUND

Several occupations require an individual to be exposed to hazards such as

flash fires or electrical arcs. To avoid being injured while working in such conditions,

these individuals typically wear protective garments constructed of materials designed

to protect them from heat and flame.

To cite an example, many utility and industrial workers wear denim garments.

As referred to herein, "denim" is a twill fabric that is yarn dyed such that one yarn

component (e.g., warp yarns) is dyed prior to constructing the fabric and the other yarn

component (e.g., filling yarns) is not. It is the weaving of the dyed yarns with the

undyed yarns that gives denim its distinctive appearance. Such denim is typically

constructed of 100% cotton. Although not ideal from the standpoint of offering

protection against flash fire and electrical arc hazards, many workers like the

appearance and feel of cotton denim garments and believe that the protection they

offer is adequate.

Unfortunately, a number of issues arise when cotton denim garments are used

to protect against flash fires, electrical arcs, and other similar hazards. Although some protection is offered by such garments, better protection could be afforded by

garments composed of flame resistant fabrics. Although it is possible to treat cotton

denim fabric in order to increase its flame resistance, this flame resistance may

degrade over the life of the fabric through physical wear and laundering. Aside from

issues concerning flame resistance, yarn dyeing processes used to create known denim

fabrics are relatively expensive as compared to piece-dyeing processes, and therefore

increase the overall cost of producing a garment.

SUMMARY Disclosed are flame resistant fabrics and garments having the appearance of

denim. In one embodiment, a piece-dyed, flame resistant fabric includes first flame

resistant yarns that extend along the fabric in a first direction and second flame

resistant yarns that extend along the fabric in a second that is different from the first

direction so as to interweave the second flame resistant yarns with the first flame

resistant yarns, wherein the first flame resistant yarns are dyed due to the piece dyeing

but the second flame resistant yarns are substantially undyed to create the denim appearance.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed fabrics and methods can be better understood with reference to

the following drawings. The components in the drawings are not necessarily to scale.

FIG. 1 is a front view of an embodiment of a protective garment.

FIG. 2 is a schematic representation of an embodiment of a fabric that can be

used to construct the garment shown in FIG. 1. FIG. 3 is a flow diagram illustrating an embodiment of a method that can be

used to dye the fabric shown in FIG. 2.

DETAILED DESCRIPTION

FIG. 1 illustrates an example protective garment 100. More particularly, FIG.

1 illustrates a pair of pants that can be worn by utility and industrial personnel to

protect against flash fire hazards, electric arc hazards, etc. It is noted that, although a

pair of pants is shown in the figure and described herein, the present disclosure more

generally pertains to protective garments, as well as the fabrics used to construct them.

Accordingly, other garments can be constructed including, for example, jackets, shirts,

overalls, etc. All such garments are intended to fall within the scope of the present

disclosure. FIG. 2 is a schematic view of an example fabric 200 that can be used to

construct the protective garment 100 shown in FIG. 1. As indicated in FIG. 2, the

fabric 200 can be constructed as a plain weave fabric that comprises a plurality of

warp yarns 202 and a plurality of filling yarns 204 that together form the body of the

fabric 2O0. Although a plain weave is depicted in FIG. 2, other configurations could

be used such as, for example, a twill. Preferably, the warp yarns 202 and filling yarns

204 are both constructed of flame resistant material. Regardless, however, the warp

yarns 2O2 and filling yarns 204 are selected such that either the warp yarns 202 or

filling yarns 204 are dyed using a piece-dyeing process while the other yarns remain

substantially undyed so as to provide the appearance of denim. The process of dyeing

the fabric 200 in this manner is discussed in greater detail below. For ease of

description, it is assumed that the warp yarns 202 are dyed while the filling yarns 204

remain substantially undyed. Note, however, that the filling yarns 204 could be dyed

and the warp yarns 202 left substantially undyed by merely reversing the selection of

materials for the warp yarns 202 and the filling yarns 204. Therefore, the fabric 200

may more generally be described as comprising first yarns that extend along the fabric in a first direction and that are dyed, and second yarns that extend along the fabric in a

second that is different from the first direction so as to interweave the first yarns and

that are substantially undyed.

hi some embodiments, the warp yarns 202 comprise a blend of inherently

flame resistant fibers and another type of fiber, such as a flame resistant (FR)

cellulosic fiber (i.e., a fiber that is not naturally flame resistant, but which can be made so through appropriate treatment). For example, a para-aramid/FR rayon blend or a

meta-aramid/FR rayon blend may be used, hi other embodiments, the warp yarns 202

comprise a blend of modacrylic and FR rayon, hi cases in which an aramid blend is

used, a para-aramid (e.g., Kevlar^® or Twaron^®)/FR rayon blend and/or a non¬

crystalline meta-aramid (e.g., Nomex^® type 462)/FR rayon blend may be used. As is

known in the art, Kevlar^® and Twaron^® fibers are composed of 100% para-aramid

while Nomex^® type 462 fibers are composed of 93% non-crystalline meta-aramid.

Although para-aramid can be difficult to dye, suitable dyeing of a blended yarn may be achievable, for instance by only or primarily dyeing the non-para-aramid

component(s). Other FR cellulosics that could be used include FR cotton, FR acetate, FR triacetate, and FR lyocell.

In some embodiments, the filling yarns 204 are composed of inherently flame

resistant material that resists the employed dyeing process and therefore remains

substantially undyed (i.e., substantially uncolored) after the piece-dyeing process used

to dye the warp yarns 202 is completed. In one embodiment, the filling yarns 204

comprise an aramid material that resists dyeing such as crystalline meta-aramid (e.g.,

Nomex^® type 450). In another embodiment, the filling yarns 204 comprise 100%

para-aramid fibers (e.g., Kevlar^® or Twaron^®). As is known in the art, Nomex^® type

450 fibers are composed of 100% crystalline meta-aramid, which is relatively difficult to dye. Typically, the resultant fabric has a weight ranging from approximately 4

ounces per square yard (osy) to approximately 15 osy.

The dyeing techniques and dyes used to achieve a flame resistant fabric having

the appearance of denim depend upon the materials selected for the warp yarns 202

and the filling yarns 204 and the desired result in terms of which component (warp or

filling) is dyed and which is not. In some embodiments, the dyeing techniques used

comprise low temperature (i.e., less than the boiling temperature) dyeing with or

without a dye-assistant (or "carrier"). Example dyeing methods are described in U.S.

Patent No. 6,547,835, which is hereby incorporated by reference. In that particular

dyes cannot be used to dye some materials and some materials can only be dyed by

certain dyes if a dye-assistant is used, it can be appreciated that the desired result,

whether it be dyed warp yarns and undyed filling yarns or undyed warp yarns and dyed

filling yarns, can be achieved by varying one or more of the materials used, dyes used,

and dye-assistant used (if any). Example dyes include direct/disperse, fiber

reactive/disperse, direct/basic, fiber reactive/basic, direct, fiber reactive, vat, and

sulfur dyes, and may be, for instance, blue or black (i.e., popular colors for denim garments).

Example fabrics and dyeing techniques are identified in Table I that result in dyed warp yarns and substantially undyed filling yarns, which yields a flame resistant

fabric having the appearance of denim. However, as noted above, the same effect can

be achieved if the filling yarns 204 are dyed and the warp yarns 204 remain

substantially undyed.

TABLE I

FIG. 3 is a flow chart that illustrates an example method for piece dyeing

fabric so as to achieve a flame resistant garment having the appearance of denim. The

first step, as shown in block 300, comprises contacting a flame resistant fabric (which includes the warp yarns and filling yarns) with a dye bath including a dye and,

optionally, a dye-assistant. The dye bath may include one or more of, for example,

direct/disperse, fiber reactive/disperse, direct/basic, fiber reactive/basic, direct, fiber

reactive, vat, and sulfur dyes. When a dye-assistant is used in the dye bath, the dye-

assistant may include one or more of, for example, N-cyclohexylpyrrolidone, benzyl

alcohol, N,N-dibutylformamide, N,N-diethylbenzamide, hexadecyltrimethyl

ammonium salt, N,N-dimethylbenzamide, N,N-diethyl-τn-toluamide, N- octylpyrrolidone, aryl ether, Halcomid M-8/10 (an approximately 50/50 blend of N₅N- dimethylcaprylamide and N,N-dimethylcapramide), and mixtures thereof. Next, as

shown in block 302, the flame resistant fabric is dyed at a peak temperature that does

not exceed the boiling temperature (e.g., 190° F), to fix the dye within one yarn

component (e.g., the warp yarns 202) but not, at least to a significant degree, the other

yarn component (e.g., the filling yarns 204).

At this point, the fabric (once rinsed and dried) will have the appearance of

conventional denim, but will further have a relatively durable flame resistance.

Accordingly, the fabric is suitable for replacement of cotton denim in garments used

by those who encounter heat and flame hazards.

Claims

I claim:

L A piece-dyed, flame resistant fabric having the appearance of denim,

the fabric comprising:

first flame resistant yarns that extend along the fabric in a first direction; and

second flame resistant yarns that extend along the fabric in a second that is

different from the first direction so as to interweave the second flame resistant yarns with the first flame resistant yarns;

wherein the first flame resistant yarns are dyed due to the piece dyeing but the

second flame resistant yarns are substantially undyed to create the denim appearance.

2. The fabric of claim 1, wherein the first flame resistant yams are warp

yarns.

3. The fabric of claim 1, wherein the first flame resistant yarns comprise

inherently flame resistant material.

4. The fabric of claim 3, wherein the first flame resistant yarns comprise

at least one of para-aramid fibers and uncrystallized meta-aramid fibers.

5. The fabric of claim 3, wherein the first flame resistant yarns comprise

modacrylic fibers.

6. The fabric of claim 1, wherein the first flame resistant yarns comprise

flame resistant cellulosic fibers.

7. The fabric of claim 1, wherein the first flame resistant yarns are dyed

one of blue and black.

8. The fabric of claim 1, wherein the second flame resistant yarns are

filling yarns.

9. The fabric of claim 1, wherein the second flame resistant yarns

comprise inherently flame resistant material.

10. The fabric of claim 9, wherein the second flame resistant yarns

comprise at least one of para-aramid fibers and crystallized meta-aramid fibers.

11. The fabric of claim 1, wherein the second flame resistant yarns resist

dyeing such that the first flame resistant yarns can be dyed without dyeing the second

flame resistant yarns in a piece-dyeing process.

12. The fabric of claim 1 , wherein the fabric is a plain weave,

13. The fabric of claim 1, wherein the fabric is a twill.

14. The fabric of claim 1, wherein the fabric has a weight ranging from

approximately 4 to 15 ounces per square yard.

15. A piece-dyed, flame resistant fabric, comprising:

flame resistant warp yarns; and

flame resistant filling yarns;

wherein the warp yarns are dyed due to the piece dyeing, but the second flame

resistant yarns are not dyed despite the piece dyeing.

16. The fabric of claim 15, wherein the warp yarns comprise at least one of

aramid fibers and modacrylic fibers.

17. The fabric of claim 16, wherein the warp yarns further comprise flame

resistant cellulosic yarns.

18. The fabric of claim 15, wherein the warp yarns are dyed one of blue

and black.

19. The fabric of claim 15, wherein the filling yarns comprise at least one

of para-aramid fibers and crystallized meta-aramid fibers.

20. The fabric of claim 15, wherein the fabric is one of a plain weave and a

twill.

21. The fabric of claim 15, wherein the fabric has a weight ranging from

approximately 4 to 15 ounces per square yard.

22. A protective garment composed of a piece-dyed fabric, comprising:

second flame resistant yarns that extend along the fabric in a second that is

different from the first direction so as to interweave with the first flame resistant

yarns;

wherein the first flame resistant yarns are dyed due to the piece dyeing and the

second flame resistant yarns are substantially undyed to create an appearance of denim

for the fabric and the garment.

23. The garment of claim 22, wherein the first flame resistant yarns are

warp yarns and the second flame resistant yarns are filling yarns.

24. The garment of claim 22, wherein the first flame resistant yarns

comprise at least one of para-aramid fibers, uncrystallized meta-aramid fibers,

modacrylic fibers, and flame resistant cellulosic fibers.

25. The garment of claim 22, wherein the second flame resistant yarns

26. The garment of claim 22, wherein the garment fabric is one of a plain

weave and a twill.

27. The garment of claim 22, wherein the garment fabric has a weight

ranging from approximately 4 to 15 ounces per square yard.

28. The garment of claim 22, wherein the garment comprises one of a

jacket, a shirt, pants, and overalls.

29. A method for dyeing a flame resistant fabric, the method comprising:

contacting a flame resistant fabric comprising flame resistant yarns extending

in first and second directions along the fabric so as to interweave with a dye bath; and

heating the dye bath such that dye is fixed within the flame resistant yarns extending in the first direction but not in the flame resistant yams extending in the

second direction so as to create the appearance of denim.

30. The method of claim 29, wherein contacting a flame resistant fabric

comprises piece dyeing a fabric that includes warp yarns that accept dyeing and filling

yarns that resist dyeing.

31. The method of claim 29, wherein contacting a flame resistant fabric

comprises piece dyeing a fabric that includes warp yarns that resist dyeing and filling

yarns that accept dyeing.

32. The method of claim 29, wherein contacting a flame resistant fabric

comprises piece dyeing a flame resistant fabric including first yarns and second yarns

that interweave the first yarns, the first yarns comprising at least one of aramid fibers,

modacrylic fibers, and flame resistant cellulosic fibers, the second yarns comprising at

least one of para-aramid fibers and crystallized meta-aramid fibers.

33. The method of claim 29, wherein contacting a flame resistant fabric

with a dye bath comprises contacting the fabric with a dye bath comprising a dye

selected from the group consisting of a direct/disperse dye, a fiber reactive/disperse

dye, a direct/basic dye, a fiber reactive/basic dye, a direct dye, a fiber reactive dye, a

vat dye, a sulfur dye, and mixtures thereof.

34. The method of claim 29, wherein contacting a flame resistant fabric

with a dye bath comprises contacting the fabric with a dye bath comprising a dye- assistant selected from the group consisting of N-cyclohexylpyrrolidone, benzyl

alcohol, N,N-dibutylformamide, N,N-diethylbenzamide, hexadecyltrimethyl

ammonium salt, N,N-dimethylbenzamide, N,N-diethyl-m-toluamide, N-

octylpyrrolidone, aryl ether, Halcomid M-8/10 (an approximately 50/50 blend of N,N-

dimethylcaprylamide and N,N-dimethylcapramide), and mixtures thereof.

35. The method of claim 29, wherein heating the dye bath comprises

heating the dye bath to a peak temperature that does not exceed 190° F.