AU2018204269B2 - Flame resistant fabrics and garments made from same - Google Patents

Abstract

Unique blends of fibers that incorporate synthetic cellulosic fibers to render fabrics made with such blends more durable than fabrics made with natural cellulosic fibers such as cotton. While more durable than cotton, the synthetic cellulosic fibers used in the blends are still inexpensive and comfortable to the wearer. Thus, the benefits of cotton (affordability and comfort) are still attained while a drawback of cotton - low durability - is avoided. In one embodiment, the fiber blend includes FR modacrylic fibers and synthetic cellulosic fibers, preferably, but not necessarily non-FR lyocell fibers such as TENCELTM and TENCEL A100TM. Other fibers may be added to the blend, including, but not limited to, additional types of inherently FR fibers, anti-static fibers, anti-microbial fibers, stretch fibers, and/or high tenacity fibers. The fiber blends disclosed herein may be used to form various types of FR fabrics. Desired colors may be imparted in a variety of ways and with a variety of dyes to the fabrics disclosed herein. Fabrics having the fibers blends disclosed herein can be used to construct the entirety of, or various portions of, a variety of protective garments for protecting the wearer against electrical arc flash and flames, including, but not limited to, coveralls, jumpsuits, shirts, jackets, vests, and trousers. 19 US2000 10272105.1

Description

FLAME RESISTANT FABRICS AND GARMENTS MADE FROM SAME

Field of the Invention

The present invention relates to protective fabrics, and more specifically to flame resistant

fabrics, having a unique blend of fibers and garments made from such fabrics.

Background of the Invention

Many occupations can potentially expose an individual to electrical arc flash and/or

flames. To avoid being injured while working in such conditions, these individuals typically

wear protective garments constructed of flame resistant materials designed to protect them from

electrical arc flash and/or flames. Such protective clothing can include various garments, for

example, coveralls, pants, and shirts. Fabrics from which such garments are constructed, and

consequently the resulting garments as well, are required to pass a variety of safety and/or

performance standards, including ASTM F 1506, NFPA 2112, NFPA 70E, MIL C 43829C.

Many protective garments have been made from fabrics comprising natural cellulosic

fibers, such as cotton. Cotton fibers are inexpensive and fabrics made from such fibers

comfortable to wear. However, the use of cotton fibers in such fabrics has many disadvantages.

To begin, cotton fibers are not durable. Thus, fabrics made with them have poor wear life and

must be replaced unacceptably often.

Furthermore, cotton fibers pose a health hazard to personnel during the fiber spinning and

fabric weaving processes. When natural cotton fibers are used to make fabrics and garments, the

cotton fibers can be inhaled and over time can cause respiratory problems, which can lead to

byssinosis or "brown lung" disease. Work environments where personnel work with natural

cotton and are exposed to breathing hazardous cotton fibers are thus subject to governmental and

regulatory restrictions for handling and processing of such fibers.

Moreover, cotton fibers are not inherently flame resistant and thus apt to burn. Thus,

these fibers (or the yarns or fabrics made with such fibers) have historically been treated with a

1 US2000 10272105.1

FR compound to render such fibers (or the yarns or fabrics made with such fibers) flame resistant.

Treatment of cotton fibers (or the yarns or fabrics made with such fibers) with an FR compound

significantly increases the cost of such fibers (or the yarns or fabrics made with such fibers).

To avoid the cost associated with such FR treatment, cotton fibers have been combined

with FR modacrylic fibers. The FR modacrylic fibers control and counteract the flammability of

the cotton fibers to prevent the cotton fibers from burning. In this way, the cotton fibers (or the

yarns or fabrics made with such fibers) need not be treated with a FR compound.

However, the FR modacrylic fibers have durability problems similar to those of cotton,

and thus fabrics made with blends of these fibers have poor wear life. Moreover, both natural

cotton fibers and FR modacrylic fibers are relatively unstable after thermal exposure, rendering it

difficult if not impossible for fabrics made with only these fibers to pass the requisite safety and

performance standards for protective garments. Thus, additional inherently FR fibers, such as

aramid fibers, have been added to the fiber blend to impart thermal stability to the blend to ensure

compliance of the resulting fabric with the requisite safety and performance standards (e.g., by

decreasing char lengths in vertical flame tests of such fabrics).

Because of the presence of cotton fibers, the resulting fabrics still exhibit durability

problems and unacceptable wear life. Thus, a need exists for fiber blends that include fibers that

are more durable than natural cellulosic fibers such as cotton but that still realize the cost and

comfort advantages of cotton in such blends.

Summary of the Invention

This invention discloses unique blends of fibers that incorporate synthetic cellulosic fibers

to render fabrics made with such blends more durable than fabrics made with natural cellulosic

fibers such as cotton. While more durable than cotton, the synthetic cellulosic fibers used in the

blends are still inexpensive and comfortable to the wearer. Thus, the benefits of cotton

(affordability and comfort) are still attained while a drawback of cotton - low durability - is

2 US2000 10272105.1 avoided. The resulting fabrics made with the fiber blends disclosed herein are flame resistant, durable, comfortable, and affordable.

In one embodiment, the fiber blend includes FR modacrylic fibers and synthetic cellulosic

fibers, preferably, but not necessarily non-FR lyocell fibers such as TENCELTM and TENCEL

A100TM. The FR modacrylic fibers and the synthetic cellulosic fibers can be combined in any

blend ratio but are preferably, although not necessarily, combined so that the percentage of FR

modacrylic fibers in the blend is greater than the percentage of synthetic cellulosic fibers in the

blend. Other fibers may be added to the blend, including, but not limited to, additional types of

inherently FR fibers, anti-static fibers, anti-microbial fibers, stretch fibers, and/or high tenacity

fibers.

The fiber blends disclosed herein may be used to form various types of FR fabrics.

By way only of example, the fibers may be used to form nonwoven fabrics or may first be formed

into yarn that is subsequently woven or knitted into a FR fabric.

In one embodiment, yarns are formed from a fiber blend having approximately 30-60%

FR modacrylic fibers, approximately 20-60% synthetic cellulosic fibers, and approximately 5

30% additional inherently FR fibers. TENCELTM and particularly TENCEL A100TM (both non

FR synthetic cellulosic fibers) and para-aramid fibers (inherently FR fibers) have performed

particularly well in this application. The yarns can subsequently be used to form FR fabrics in a

variety of ways (e.g. weaving, knitting, etc.), all well known in the industry. Fabrics made

from the unique fiber blends disclosed herein comply with a variety ofthe thermal protection

standards, rendering them suitable for use in protective garments.

Desired colors may be imparted in a variety of ways and with a variety of dyes to the

fabrics disclosed herein having a blend of synthetic cellulosic, FR modacrylic, and optionally

additional inherently FR fibers. The fabrics may be dyed or printed to comply with the standard

for high-visibility safety apparel known in the industry as ANSI 107-2004 (and the European

3 US2000 10272105.1 equivalent EN 471) as well as with the military's infrared reflective requirements (including, but not limited to, those promulgated under MIL-C-83429 and GL-PD-07-12 (2/28/07)).

Fabrics having the fibers blends disclosed herein can be used to construct the entirety of,

or various portions of, a variety of protective garments for protecting the wearer against electrical

arc flash and flames, including, but not limited to, coveralls, jumpsuits, shirts, jackets, vests, and

trousers. In one embodiment, a fabric having blends of fibers disclosed herein is used to form at

least a portion of an advanced combat shirt.

Detailed Description of the Invention

This invention relates to unique blends of fibers that render the resulting fabric flame

resistant, durable, comfortable, and affordable. In one embodiment, the fiber blend includes FR

modacrylic fibers and manmade or synthetic cellulosic fibers. The FR modacrylic fibers and the

synthetic cellulosic fibers can be combined in any blend ratio but are preferably, although not

necessarily, combined so that the percentage of FR modacrylic fibers in the blend is greater than

the percentage of synthetic cellulosic fibers in the blend.

Any FR modacrylic fibers able to extinguish non-FR fibers may be used, including, but

not limited to, PROTEXTM fibers (including but not limited to PROTEX WTM and PROTEX CTM

fibers) available from Kaneka Corporation of Osaka, Japan, SEFTM available from Solutia, or

blends thereof. The synthetic cellulosic fibers may be, but are not limited to, rayon, FR rayon,

lyocell, MODALTM, cellulose acetate, or blends thereof. An example of a suitable rayon fiber is

Viscose by Lenzing, available from Lenzing Fibers Corporation. Examples of lyocell fibers

include TENCELTM and TENCEL A100TM, both available from Lenzing Fibers Corporation.

Examples of FR rayon fibers include Lenzing FRTM, also available from Lenzing Fibers

Corporation, and VISILTM, available from Sateri.

The synthetic fibers used in the blends disclosed herein can be, but preferably are not, FR

treated given that they are being blended with FR modacrylic fibers that control and counteract

the flammability of the synthetic fibers to prevent such fibers from burning. Use of synthetic 4 US2000 10272105.1 cellulosic fibers that have not been FR-treated significantly reduces the cost of such fibers (e.g., approximately $1/pound for non-FR treated synthetic cellulosic fibers vs. approximately

$6/pound for FR-treated synthetic cellulosic fibers).

Non-FR lyocell fibers such as TENCELTM and TENCEL A1OOTM fibers have proven to be

particularly suitable in this application. While similar to cotton fibers in that these fibers are

inexpensive and comfortable, they are more durable than natural cotton fibers and have proven

very resistant to abrasion and very moisture absorbent. Consequently, fabrics made from these

fibers have long wear life and are comfortable to the wearer. TENCEL AlOOTM fibers are less

susceptible to fibrillation, which results when the ends of the fibers split to impart a fuzzy or

prematurely worn appearance to garments made with such fibers. It has been found that fabrics

made with TENCEL AlOOTM fibers are thus better able to retain their appearance even after

repeated launderings. Moreover, unlike natural cotton typically used in these blends, because

these cellulosic fibers are manmade fibers, they consequently do not pose a breathing hazard to

personnel during the fiber spinning or fabric fabrication process.

In an alternative embodiment, an additional type (or types) of inherently FR fibers (i.e., in

addition to the FR modacrylic fibers which are inherently FR) may be added to the FR

modacrylic/synthetic cellulosic fiber blend. The additional inherently FR fibers may include, but

do not have to include, para-aramid fibers, meta-aramid fibers, polybenzimidazole (PBI) fibers,

polybenzoxazole (PBO) fibers, melamine fibers, carbon fibers, pre-oxidized acrylic fibers,

polyacrylonitrile (PAN) fibers, TANLONTM (available from Shanghai Tanlon Fiber Company),

polyamide-imide fibers such as KERMELTM, and blends thereof. Examples of para-aramid fibers

include KEVLARTM (available from DuPont), TECHNORATM (available from Teijin Twaron BV

of Arnheim, Netherlands), and TWARONTM (also available from Teijin Twaron BV). Examples

of meta-aramid fibers include NOMEXTM (available from DuPont), CONEXTM (available from

Teijin), and APYEILTM (available from Unitika). An example of melamine fibers is BASOFILTM

(available from Basofil Fibers). An example of PAN fibers is Panox@ (available from the SGL 5 US2000 10272105.1

Group). As explained above, such inherently FR fibers impart the requisite thermal stability to

the blend to enable fabrics made from such blends to be used in protective garments.

In other embodiments, additional fibers, including, but not limited to (1) anti-static fibers

to dissipate or minimize static, (2) anti-microbial fibers, (3) stretch fibers (e.g., spandex), and/or

(4) high tenacity fibers such as, but not limited to, nylon and/or polyester fibers (such as

VECTRAN T M) are added to the blends to improve the wear property of fabrics made with such

blends.

The fiber blends disclosed herein may be used to form various types of FR fabrics.

By way only of example, the fibers may be used to form nonwoven fabrics or may first be formed

into yarn that is subsequently woven or knitted into a FR fabric.

In one embodiment, yarns are formed from a fiber blend having approximately 30-60%

FR modacrylic fibers, approximately 20-60% synthetic cellulosic fibers, and approximately 5

30% additional inherently FR fibers. TENCELTM and particularly TENCEL A100TM (both non

FR synthetic cellulosic fibers) and para-aramid fibers (inherently FR fibers) have performed

particularly well in this application. The same types of FR modacrylic fibers, synthetic cellulosic

fibers, and additional inherently FR fibers need not be used in the blend. Rather, multiple types

of each may be blended together.

The yarns can be formed in conventional ways well known in the industry. The yarns

may be spun yarns and can comprise a single yarn or two or more individual yarns that are

twisted, or otherwise combined, together. In one embodiment, the yarns are air jet spun yarns.

Typically, the yarns comprise one or more yarns that each have a yarn count in the range of

approximately 5 to 60 cc. In one embodiment, the yarns comprise two yarns that are twisted

together, each having a yarn count in the range of approximately 10 to 60 cc.

The yarns can subsequently be used to form FR fabrics in a variety of ways, all well

known in the industry. The yarns can be knitted or woven. In one embodiment, the FR fabric is

formed as a plain weave fabric that comprises a plurality of body yarns. However, it will be 6 US2000 10272105.1 appreciated that other configurations could be used including, for instance, a rip-stop or a twill weave such as a 2 X1 right hand twill weave.

Regardless of the manner by which the FR fabric is formed (nonwoven, knitted, woven,

etc.), the FR fabric can be made from a blend of fibers that includes having approximately 30

60% FR modacrylic fibers, approximately 20-60% synthetic cellulosic fibers (preferably, but not

necessarily, TENCELTM fibers and more preferably TENCEL A100TMfibers) and approximately

5-30% additional inherently FR fibers (preferably, but not necessarily, para-aramid fibers). As

discussed above, the FR fabric may include a fiber blend that includes anti-static, anti-microbial,

stretch, and/or high tenacity fibers.

In a much more specific example that is certainly not intended to limit the scope of the

invention discussed herein, the FR fabric includes a blend of between approximately 40-50% FR

modacrylic fibers, approximately 30-40% synthetic cellulosic fibers (preferably, but not

necessarily, TENCELTMfibers and more preferably TENCEL A100TMfibers), and approximately

10-15% aramid fibers (preferably, but not necessarily, para-aramid fibers).

The FR fabrics formed with the blends disclosed herein preferably, but not necessarily,

have a weight between approximately 3-12 ounces per square yard ("osy") and more preferably

between approximately 5-9 osy.

Specific examples of embodiments of fabrics in accordance with the invention are

described as follows.

Fabric Blend #1: One embodiment of the invention is a fabric with a blend of

approximately 50% PROTEX WTM (FR modacrylic), approximately 40% TENCEL A100TM

(cellulosic), and approximately 10% TWARONTM(para-aramid).

Fabric Blend #2: Another embodiment of the invention is a fabric with a blend of

approximately 45% PROTEX WTM (FR modacrylic), approximately 35% TENCEL A100TM

(cellulosic), approximately 10% Lenzing FRTMor FR rayon (cellulosic), and 10% TWARONTM

(para-aramid). 7 US2000 10272105.1

Fabric Blend #3: Another embodiment of the invention is a fabric with a blend of

approximately 50% PROTEX WTM (FR modacrylic), approximately 35% TENCEL A100TM

(cellulosic), approximately 10% nylon, and approximately 5% TWARONTM (para-aramid).

Fabric Blend #4: Another embodiment of the invention is a fabric with a blend of

approximately 48% PROTEX WTM (FR modacrylic), approximately 37% TENCEL A100TM

(cellulosic), and approximately 15% TWARONTM (para-aramid).

As evidenced in Table 1, FR fabrics made from the unique fiber blends disclosed herein

comply with the before-wash vertical flammability requirements set forth in ASTM F 1506 and

NFPA 70E, including having acceptable arc thermal protective values ("ATPV"). Workers who

may be exposed to accidental electric arc flash risk serious burn injury unless they are properly

protected. NFPA 70E is the standard that addresses electrical safety requirements, providing

information on all aspects of electrical safety in the workplace. NFPA 70E offers a method to

match protective clothing to potential exposure levels incorporating Hazard Risk Categories

(HRC). Protective fabrics are tested to determine their ATPV or arc rating in cal/cm2 (calories

per square centimeter). The ATPV is determined by ASTM test method F 1959, where sensors

measure thermal energy properties of protective fabric specimens during exposure to a series of

electric arcs. The measured arc rating determines the HRC for a fabric as follows:

Hazard Risk Category and ATPV

HRC 1: ATPV: 4 cal/cm 2

HRC 2: ATPV: 8 cal/cm

HRC 3: ATPV: 25 cal/cm 2

HRC 4: ATPV: 40 cal/cm 2

In addition to complying with ASTM F 1506 and NFPA 70E as discussed above, Fabric

Blends #2-#4 comply with the before-wash vertical flammability requirements set forth in ASTM

2112, including having acceptable char lengths (as measured with the testing method set forth in

ASTM 6413). 8 US2000 10272105.1

TABLE 1

Fabric Blend Fabric Weight Char length ATPV Ratio of (ounces per square (inches) (cal/cm 2) ATPV to yard or "osy") warp x fill Weight

Fabric Blend #1 9.3 4.2 x 3.5 8.8 0.95 Fabric Blend #2 8.4 3.1 x 2.8 8.2 0.97 Fabric Blend #3 8.6 3.3 x 2.3 6.8 0.79 Fabric Blend #4 8.4 3.3 x 2.6 9.3 1.10 Fabric Blend #4 7.6 3.5 x 2.7 8.4 1.11

Fabrics made from the fiber blends contemplated in this application also have surprisingly

high resistances to abrasion. As explained above, TENCELTM and TENCEL A100TM fibers are

very durable fibers. It is not surprising, therefore, that Taber abrasion test results of fabrics made

from fiber blends having such fibers indicate substantially high resistance to abrasion - indeed

almost as high as fabrics made from 100% inherently FR fibers and higher than fabrics made with

other fiber blends that comply with the ASTM F 1506, NFPA 2112, and NFPA 70E standards.

Moreover, while abrasion resistance is high, the inclusion of modacrylic and cellulosic fibers in

the blends contemplated herein render the resulting fabric soft and thus more comfortable to the

wearer.

Desired colors may be imparted in a variety of ways to the fabrics disclosed herein having

a blend of synthetic cellulosic, FR modacrylic, and optionally additional inherently FR fibers. In

one embodiment, the synthetic cellulosic fibers and/or modacrylic fibers are dyed (either prior to

their formation into yarn, after formation into yarns, or in the final fabric). The synthetic

cellulosic and/or modacrylic fibers may be dyed any of a variety of colors, including, but not

limited to, yellow, fluorescent yellow, green, orange, red, blue, gray, etc. using the dyes (or

combinations of dyes) disclosed herein.

Dyeing may be achieved using a variety of well-known techniques, including exhaust

dyeing processes using a jet, beam, beck, or jig dyeing apparatus or continuous dyeing processes,

all of which are well known in the art. Suitable dyes for dyeing the modacrylic fibers include, but 9 US2000 10272105.1 are not limited to, basic dyes and disperse dyes. Suitable dyes for dyeing the synthetic cellulosic fibers include, but are not limited to, fiber reactive dyes, direct dyes, and vat dyes.

In one embodiment, the fabrics are dyed to comply with the standard for high-visibility

safety apparel known in the industry as ANSI 107-2004 and the European equivalent EN 471. To

comply with ANSI 107-2004, a fabric must (1) be dyed to a high-visibility shade (measured by

reference to a fabric's chromaticity and luminance) and (2) maintain that high-visibility shade

after being subjected to light for a specified period of time (an attribute referred to in the standard

as "light fastness"). The dyes for each of the synthetic cellulosic fibers and the modacrylic fibers

are thus selected so as to achieve dyeing of these fibers to a high-visibility shade. Dyes that

enable dyeing of the synthetic cellulosic fibers to a high-visibility shade include, but are not

limited to, direct dyes (including, but not limited to, Direct Yellow 96) and fiber reactive dyes

(including, but not limited to, Remazol Luminous Yellow FL). Dyes that enable dyeing of the

FR modacrylic fibers to a high-visibility shade include, but are not limited to, basic dyes such as

Basic Yellow 40.

In one example, the FR modacrylic fibers and the synthetic cellulosic fibers of fabrics

having Fabric Blends #1-4 (disclosed above) as well as an additional fabric blend (Fabric Blend

#5 having approximately 50% PROTEX WTM (FR modacrylic), approximately 39% TENCEL

A100TM (cellulosic), approximately 10% TWARONTM (para-aramid), and approximately 1%

antistat)) were dyed in accordance with a two-step exhaust dyeing process using Basic Yellow 40

to dye the FR modacrylic fibers and Remazol Luminous Yellow FL to dye the TENCEL A100TM

fibers. The results are set forth below in Table 2.

10 US2000 10272105.1

TABLE2

FABRIC % Basic % Alkali (Soda Ash) Caustic Salt Pass BLEND Yellow 40 Remazol (Sodium ANSI Dye (owf) Yellow FL Sulphate) 107 Dye (owf) 2004? Fabric Blend # 1 1.20 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 1 1.20 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 1 2.25 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 1 2.25 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 2 1.20 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 2 1.20 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 2 2.25 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 2 2.25 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 3 1.20 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 3 1.20 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 3 2.25 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 3 2.25 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 4 1.20 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 4 1.20 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 4 2.25 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 4 2.25 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 5 1.20 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 5 1.20 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 5 2.25 3.85 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%) Fabric Blend # 5 2.25 5.00 5.00g/L/1.292 80 g/L Yes g/L(NaOH50%)

11 UJS2000 10272105.1

Fabrics having the FR modacrylic/synthetic cellulosic blends (and particularly those using

TENCELTM and TENCEL A100TM fibers) may be dyed in compliance with the military's infrared

reflective requirements (including, but not limited to, those promulgated under MIL-C-83429 and

GL-PD-07-12 (2/28/07)). Vat dyes have proven particularly suitable for dyeing the fabrics in

compliance with such standards. Vat dyeing techniques, such as, but not limited to, those

disclosed in Textile Dyeing and Coloration by J.R. Aspland (Chapters 4: Vat Dyes: General and

5: Vat Dyes and their Application), are well known in the art and thus not discussed in detail

herein. The fabrics disclosed herein may also be printed with dyes or pigments. For example,

such fabrics may be printed in compliance with the military's infrared reflective requirements

with vat dyes using printing techniques well known in the art.

After all dyeing has been completed, the fabric then can be finished in conventional

manner. This finishing process can include the application of FR treatments, anti-microbial

agents, insect repellent agents, pesticides, soil release agents, wicking agents, water repellents

(e.g., perfluorohydrocarbon), stiffening agents, softeners, and the like.

Fabrics having the fiber blends disclosed herein can be used to construct the entirety of, or

various portions of, a variety of protective garments for protecting the wearer against electrical

arc flash and flames, including, but not limited to, coveralls, jumpsuits, shirts, jackets, vests, and

trousers. Retroreflective elements, such as strips of retroreflective tape, may be provided on

portions of the exterior of the garments to enhance the visibility of the garment wearer.

In one embodiment, a fabric having blends of fibers disclosed herein is used to form at

least a portion of an advanced combat shirt. Advance combat shirts are worn under bullet proof

vests. When a bullet proof vest is positioned over the shirt, the shoulders and sleeves of the shirt

typically remain exposed but the body portion of the shirt is substantially covered by the vest.

Thus, the shoulders and sleeves of the shirt have traditionally been made from woven or heavy

weight knit FR fabrics (such as those disclosed in U.S. Patent No. 6,867,154, the entirety of

which is herein incorporated by reference) that protect the wearer against flame and radiant 12 US2000 10272105.1 energy and are typically printed (such as with a camouflage pattern) to ensure the wearer does not stand out in his or her surrounding environment.

Because the body portion of the shirt is concealed by the bullet proof vest which protects

the wearer's torso, it need not be made from the same materials or afford the same level of FR

protection to the wearer. The inventors have discovered that forming the body portion of the shirt

from an FR fabric having a blend that includes FR modacrylic and synthetic cellulosic fibers

results in a shirt with better wear properties that is more comfortable to the wearer. In one

embodiment, the body portion of the shirt is formed of a 50/50 blend of FR modacrylic fibers and

synthetic cellulosic fibers (suitable examples of each of which are identified in the discussion

above).

The blend need not only include FR modacrylic and synthetic cellulosic fibers, however.

Rather, other fibers may be added to the blend, including, but not limited to, additional inherently

FR fibers (suitable examples of which are identified in the discussion above), polyester fibers,

nylon fibers, or fibers that impart stretchability to the resulting fabric (e.g., spandex). In an

alternative embodiment, the fiber blend includes between approximately 30-60% FR modacrylic

fibers, approximately 20-60% synthetic cellulosic fibers, approximately 5-30% additional

inherently FR fibers, and between 5-25% nylon fibers. In a more specific embodiment, the fiber

blend includes approximately 50% modacrylic fibers (and preferably, but not necessarily,

PROTEX WTM fibers), 30% lyocell fibers (and preferably, but not necessarily, TENCEL A100TM

fibers), 10% para-aramid fibers (and preferably, but not necessarily, TWARONTM fibers), and

10% nylon fibers.

The fiber blend is formed into yarns that is then used to form the fabric for use in the body

portion of the shirt. While any type of yarn may be formed, spun yarns are particularly suitable

in this application given their high absorptive properties. It has been found that a fabric provided

with apertures (i.e., a mesh fabric) is particularly well-suited in this application because the

resulting mesh fabric is breathable and allows air to circulate under the vest and thus keeps the 13 US2000 10272105.1 wearer cool. The mesh fabric may be formed in a variety of ways, with knitting, and particularly circular knitting, being particularly suitable.

Any portion of the shirt may be formed from the mesh material. Depending on the

stretchability of the mesh, it may be desirable to incorporate stretchable panels of FR fabric into

the shirt (such as in side panels of the shirt) for ease of donning and removing the garment by the

wearer. The stretchable panels may be formed of any FR fabric, including, but not limited to, the

fabrics contemplated herein.

The foregoing is provided for purposes of illustrating, explaining, and describing

embodiments of the present invention. Further modifications and adaptations to these

embodiments will be apparent to those skilled in the art and may be made without departing from

the scope or spirit of the invention.

In the specification the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises".

The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the referenced prior art forms part of the common general knowledge in Australia.

14 US2000 10272105.1

Claims (26)

The claims defining the invention are as follows:

1. A single layer woven or knitted flame resistant fabric for garments formed of yarns comprising a fiber blend, wherein: i. the fiber blend comprises an intimate blend of modacrylic fibers, non-flame resistant lyocell fibers, and aramid fibers; ii. the aramid fibers constitute at least 10% of the fiber blend; iii. the lyocell fibers constitute greater than 40% and no more than 60% of the fiber blend; iv. the modacrylic fibers constitute at least 30% and less than 60% of the fiber blend; and v. the fabric has a fabric weight greater than or equal to 3 ounces per square yard (osy) and less than 7.8 osy.

2. The fabric of claim 1, wherein the aramid fibers constitute more than 10% of the fiber blend.

3. The fabric of any preceding claim, where the aramid fibers constitute approximately 10-15% of the fiber blend.

4. The fabric of any preceding claim, wherein the aramid fibers comprise para aramid fibers.

5. The fabric of any preceding claim, wherein at least some of the yarns are spun yarns comprising the fiber blend.

6. The fabric of any preceding claim, wherein all of the yarns in the fabric comprise the fiber blend.

7. The fabric of any preceding claim, wherein the fiber blend comprises at least 30% and less than or equal to 40% modacrylic fibers.

8. The fabric of any preceding claim, wherein the modacrylic fibers comprise a first percentage of the fiber blend, the non-flame resistant lyocell fibers comprise a second percentage of the fiber blend, and the second percentage does not exceed the first percentage.

9. The fabric of any preceding claim, wherein the modacrylic fibers comprise a first percentage of the fiber blend, the non-flame resistant lyocell fibers comprise a second percentage of the fiber blend, the aramid fibers comprise a third percentage of the fiber blend, and the sum of the second and third percentages is greater than the first percentage.

10. The fabric of any preceding claim, wherein the modacrylic fibers comprise a first percentage of the fiber blend, the non-flame resistant lyocell fibers comprise a second percentage of the fiber blend, the aramid fibers comprise a third percentage of the fiber blend, and the sum of the first and third percentages is greater than the second percentage.

11. The fabric of any preceding claim, wherein the modacrylic fibers comprise a first percentage of the fiber blend, the non-flame resistant lyocell fibers comprise a second percentage of the fiber blend, the aramid fibers comprise a third percentage of the fiber blend, and the third percentage is less than the first percentage and is less than the second percentage.

12. The fabric of any preceding claim, wherein the fiber blend further comprises a plurality of high tenacity fibers.

13. The fabric of claim 12, wherein the high tenacity fibers comprise at least one of nylon fibers or polyester fibers.

14. The fabric of any preceding claim, wherein the non-flame resistant lyocell fibers are substantially non-fibrillating.

15. The fabric of any preceding claim, wherein the fabric has a weight greater than or equal to 3 osy and less than or equal to 7.5 osy, 7.0 osy, 6.5 osy, 6.0 osy or 5.0 osy.

16. The fabric of any preceding claim, wherein the fabric comprises an arc thermal protection value when tested according to ASTM Test F1959 and wherein the ratio of the arc thermal protection value to the weight is at least 1.05.

17. The fabric of claim 16, wherein the ratio is at least 1.10.

18. The fabric of any preceding claim, wherein the fabric has a before-wash char length less than or equal to 4.0 inches, 3.5 inches, 3.0 inches or 2.5 inches when tested according to ASTM Test D6413.

19. The fabric of any preceding claim, wherein the fabric has an afterflame less than 2 seconds when tested according to ASTM Test D6413.

20. The fabric of any preceding claim, wherein the fabric complies with at least one of ANSI 107-2004, NFPA 2112, and NFPA 70E.

21. The fabric of any preceding claim, wherein at least some of the fibers in the fabric are dyed.

22. The fabric of claim 21, wherein at least some of the modacrylic fibers are dyed with at least one of a basic dye or a disperse dye.

23. The fabric of any one of claims 21 and 22, wherein at least some of the non-flame resistant lyocell fibers are dyed with at least one of a fiber reactive dye, direct dye, or vat dye.

24. A garment comprising the fabric as claimed in any preceding claim.

25. The garment of claim 24, wherein the garment is at least one of a coverall, jumpsuit, shirt, trousers, jacket, or vest.

26. The garment of any one of claims 24 and 25, wherein the garment is a single-layer garment and the single-layer comprises the fabric.