Fabric and yarn for protective garments

Abstract

The present invention is a yarn or fabric useful in protective garments. The yarn or fabric is made of flame resistant fibers and microdenier flame resistant fibers. The flame resistant fibers are selected from the group consisting of inherently flame resistant fibers, treated fibers, and combinations thereof. The microdenier flame resistant fibers are selected from the group consisting of microdenier inherently flame resistant fibers, microdenier treated fibers, and combinations thereof. The weight ratio of said flame resistant fibers to said microdenier flame resistant fibers is in the range of 4-9:2-6.

Description

FIELD OF THE INVENTION

[0001] The invention is directed to a fabric and a yarn used to make protective garments.

BACKGROUND OF THE INVENTION

[0002] Protective clothing refers to primary and secondary protective clothing (per ASTM Standard F1002-86). Primary protective clothing is designed for activities where significant exposure to molten substance splash, radiant heat, or flame is likely to occur. Secondary protective clothing, on the other hand, is designed for continuous wear in areas where intermittent exposure to molten substance splash, radiant heat, and/or flame is possible.

[0003] Protective clothing in the work place is important because it is the employer's responsibility to identify risks and hazards in the workplace and seek out appropriate protective garments and equipment for the protection of workers. Common workplace hazards include, for example: flammable liquids, flammable soils, molten metals, sparks, slag from flame cutting, welding, open flames, high voltage electrical discharges, electric arc events, vapors from volatile liquids, and combustible dusts. These hazards may be encountered in foundries, at electrical utilities, in the chemical, oil, gas and petrochemical industries, in auto racing, to mention a few.

[0004] Fabrics have been developed for use in protective clothing. Those fabrics may be made with treated fibers, inherently flame resistant fibers, or combinations thereof. A treated fiber is, typically, a conventional textile fiber that has been treated with a flame retardant, a chemical substance used to impart flame resistance. For example, two treated fibers are FR cotton or FR rayon, both FR cellulosics. Inherently flame resistant fibers are those fibers that have flame resistance as an essential characteristic of the fiber. For example, inherently flame resistant fibers include: aramids, polyamide imides, melamines, polybenzimidazole (PBI), polyimides, polyphenylene benzodisoxazole (PBO), polyphenylene sulfide (PPS), polyetherether ketone (PEEK), and the like. Most often, these fibers are blended together to obtain a yarn for a fabric with a particular blend of properties. Those properties include thermal protection, static resistance, comfort, durability, stability, appearance, ease of laundry maintenance, color, and relative cost.

[0005] Popular fabrics include: PBI GOLD®, NOMEX®, NOMEX®IIIA, COMFORT BLEND®, NOMEX Freestyle, and INDURA® ULTRASOFT. PBI GOLD& is a 40% PBI/60% aramid blend (all % are by weight of the fabric). NOMEX® is a blend of 95% meta-aramid (NOMEX) fiber/5% para-aramid (KEVLAR) fiber. NOMEX IIIA is a blend of 93% meta-aramid (NOMEX) fiber/5% para-aramid (KEVLAR) fiber/2% static dissipative fiber. COMFORT BLEND® is 65% NOMEX IIIA/35% FR rayon blend. NOMEX Freestyle is 93% NOMEX IIIA/5% para-aramid (KEVLAR) fiber/2% antistatic fiber. INDURA ULTRASOFT is 88% FR cotton/12% nylon blend. Each of these fabrics has its own unique blend of properties. Flame Resistant Protective Apparel, An Industry Update 2001/2002, Bulwark Protective Apparel, a Division of VF Workwear, Inc., Nashville, Tenn., incorporated herein by reference.

[0006] There exists, however, a need for new fabrics that will meet new and emerging needs of the industry.

SUMMARY OF THE INVENTION

[0007] The present invention is a yarn or fabric useful in protective garments. The yarn or fabric is made of flame resistant fibers and microdenier flame resistant fibers. The flame resistant fibers are selected from the group consisting of inherently flame resistant fibers, treated fibers, and combinations thereof. The microdenier flame resistant fibers are selected from the group consisting of microdenier inherently flame resistant fibers, microdenier treated fibers, and combinations thereof. The weight ratio of said flame resistant fibers to said microdenier flame resistant fibers is in the range of 4-9:2-6.

Description of the Invention

[0008] Fabrics are planar structures made of fibers and/or yarns assembled by various means such as weaving, knitting, tufting, felting, braiding, or bonding of webs to give the structure sufficient strength and other properties required for its intended use. A yarn is a generic term for a continuous strand of textile fibers, filaments, or materials in a form suitable for knitting, weaving, or otherwise intertwining to form a fabric. Yarn occurs, for example, in the following forms: (1) a number of fibers (e.g., staple) twisted together (spun yarn); (2) a number of filaments laid together without twist (a zero-twist yarn); (3) a number of filaments laid together with a degree of twist; (4) a single filament with or without twist (a monofilament); or (5) a narrow strip of materials, such as paper, plastic film, or metal foil, with or without twist, intended for use in a textile construction.

[0009] The yarns and fabrics discussed hereinafter are preferably used as secondary protective clothing, but may be used otherwise, for example, as primary protective clothing. The garments formed from these yarns and fabrics include, but are not limited to, shirts, pants, coveralls, overalls, jackets, liners, coats, parkas, headwear, and footwear. The fabrics may be laminated or combined with other fabrics or materials to enhance functionality.

[0010] The fabrics are preferably woven or knitted. Woven fabrics include plain, twill, and satin weaves. Knitted fabrics include warp and weft knitted fabrics. The fabrics are preferably made of the yarn hereinafter described, but are not so limited. Instead, fabrics within the scope of present invention have a weight ratio of flame resistant fibers (i.e., inherently flame resistant fibers and treated fibers) to microdenier flame resistant fibers (i.e., inherently flame resistant fibers and treated fibers having microdeniers) is in the range of 4-9:2-6. Preferably, the ratio is 1:1. Alternatively, the ratio of inherently flame resistant fibers:microdenier flame resistant fibers:treated fibers is in the range of 1-3:2-6:3-6. Preferably, the ratio is 2:5:3. Other fibers may be added so long as the foregoing ratios are maintained. For example, a conventional textile fiber could be added to a blend having the foregoing ratio.

[0011] The invention will be further described with reference to a yarn, it being understood that the foregoing fabric discussion is applicable to the following yarn as well as the following is applicable to foregoing fabric discussion.

[0012] The yarn comprises: 10-30% by weight of the yarn of an inherently flame resistant fiber (filament or staple); 20-60% by weight of a microdenier flame resistant fiber (filament or staple); and 20-60% by weight of a treated fiber (filament or staple). Preferably, the yarn comprises 20% of the inherently flame resistant fiber; 50% of the microdenier flame resistant fiber; and 30% of the treated fiber.

[0013] The inherently flame resistant fibers may be selected from the group consisting of: aramids, polyamide imides; melamines, polybenzimidazoles (PBI), polyimides, polyphenylene benzodisoxazoles (PBO), polyphenylene sulfides (PPS), polyether ketones (PEK), and polyetherether ketones (PEEK), and the like. These fibers are known and commercially available. For example, aramids (meta-aramids and para-aramids) are available as TWARONO, CONEX®, and TECHNORA® from Teijin Co. of Osaka, Japan; NOMEX® and KEVLAR® from DuPont of Wilmington, Delaware; P84 from Imitech of Austria; and KERMEL® from Kermel Company of Colmar, France. Melamines (melamine formaldehydes) are available as BASOFIL® from Basofil Fibers LLC of Charlotte, N.C. PBI is available from Celanese Advanced Mateirals, Inc, of Charlotte, N.C. PBO is available as ZYLON® from Toyobo Co. Ltd. of Osaka, Japan. The preferred inherently flame resistant fibers include aramids, melamines, PBI, and PBO. Most preferred is PBI.

[0014] The treated fiber may be any conventional fiber that has been treated with a conventional flame retardant. For example, treated fibers may include FR cellulosics. Cellulosics include cotton, rayon, acetate, and triacetate. Preferred treated fibers FR cotton and FR rayon. Most preferred is FR rayon.

[0015] The microdenier flame resistant fiber may be any inherently flame resistant fiber or treated fiber having a denier less than 1 (or 0.1 tex per filament, or a diameter less than 10 microns). Preferably, this fiber is a microdenier inherently flame resistant fiber. Most preferably, this fiber is a microdenier aramid, for example, microdenier TWARONO from Teijin Co. of Osaka, Japan.

[0016] The yarns are made in a conventional fashion. Moreover, the yarns may include other conventional textile fibers (natural or man-made) provided that the addition of such fibers does not have a detrimental impact on the overall performance of the yarns, fabric, or garment.

[0017] The foregoing invention may be better understood with reference to the following non-limiting examples.

[0018] In the Table, the invention is compared to other fabrics used in protective garments. The test methods are set forth in the Table. INV refers to the inventive fabric which was made from yarns consisting of 20% PBI staple, 50% microdenier aramid (0.8 denier per filament, 2 inch (5 cm) staple), and 30% FR rayon. The comparative materials were conventional fabrics as noted above.

TABLE
	Test		Indura	Indura	Nomex	Nomex
Properties	Method	INV	Ultrasoft	Ultrasoft	Freestyle	Freestyle
Weight, oz/yd2		4.5	5.5	7.0	4.5	6.0
Nominal
Weight, oz/yd2 Actual		4.66	5.91	7.54	4.36	6.14
Weave		Twill	Twill	Twill	Plain	Plain
Moisture Regain	D2654	6.66	7.56	7.66	5.45	5.51
Air Permeability	D737	100.6	64.6	33.2	219.5	71.2
(ft3/ft2/min)
Elmendorf Tear	F1506/	19.4 × 20.7	5.1 × 3.3	8.4 × 7.0	8.2 × 12.9	7.2 × 12.4
Resistance(lbf)(W × F)	D1424
Tear Strength	F1506	13.1 × 10.0	2.1 × 2.2	5.0 × 4.0	11.3 × 8.1	7.5 × 4.5
(Tongue)(Single Rip)	D2261
Grab Strength (GS)	F1506/	164.6 × 122.8	72.5 × 69.6	76.0 × 69.3	200.9 × 108.3	300.9 × 177.2
(lbf)(W × F)	D5034
GS After Thermal		13.3 × 11.9	0.4 × 0.7	0.5 × 0.7	14.6 × 6.7	19.8 × 18.2
Exp. (8 sec)
Tensile, 1-Inch Strip	D5035	118.1 × 120.2	62.2 × 51.0	97.0 × 52.3	82.6 × 54.5	114.6 × 84.0
(lbf)(W × F)
Taber Abrasion	D5035	231	137	108	86	169
H18 500 gm
(cycles to failure)
Laundry Shrinkage(%)	AATCC
5X Wash	135	1.2 × 2.5	0.8+ × 2.6	1.4 × 1.1	2.6 × 2.6	2.2 × 3.4
25X Wash		2.8 × 4.1	0.7 × 2.9	3.6 × 1.3	4.3 × 4.2	3.2 × 4.7
Heat and Thermal	NFPA	1.3 × 1.0	2.4 × 0.6	2.7 × 0.0	2.2 × 1.3	1.3 × 1.3
Shrinkage(%)	2112
10.0 max
Flammability	D6413
Original
Char Length (in)		0.40 × 0.49	2.87 × 3.21	2.83 × 2.53	1.69 × 2.13	1.89 × 1.96
6.0 max
Afterflame (sec)		0.0 × 0.0	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0
2.0 max
Afterglow (sec)		1.02 × 1.07	1.19 × 0.90	1.08 × 1.19	0.86 × 0.83	1.04 × 1.15
25X Wash/Dry
Char Length (in)		0.41 × 0.27	2.50 × 2.65	2.72 × 2.49	2.08 × 1.52	1.88 × 2.40
6.0 max
Afterflame (sec)		0.0 × 0.0	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0
2.0 max
Afterglow (sec)		1.48 × 1.28	0.91 × 0.66	1.05 × 1.36	3.41 × 3.10	6.60 × 2.39
Thermal Protective	NFPA	11.3	7.4	9.6	11.6	13.1
Performance(TPP)	2112
TPP/osy		2.5	1.3	1.3	2.7	2.2
Preformance (RPP)		8.4	7.6	9.0	5.6	7.6
ARC FLASH
TESTING
Single Layer		4.7	5.6	7.5	4.5	6.4
wt osy n = 3
laundering
Arc Thermal	F1959/	5.9	5.5	8.1	4.8	5.7
Performance Linear	F1959M
(ATPV)
ATPV/OSY		1.26	0.98	1.80	1.10	0.89
Linear HAF		67.4	64.1	73.4	54.4	62.1
Arc Thermal	F1959/	6.0	5.6	7.9	4.8	5.9
Performance Logistical	F1959M
(ATPV)
ATPV/OSY		1.28	1.00	1.05	1.07	0.92
Single Layer With		9.2	10.1	12.0	8.9	10.9
nominal 4.5 osy
Cotton Tshirt
wt osy n = 3
laundering
Linear(Ebt)	F1959/	16.0	10.3	14.7	9.2	13.4
	F1959M
Ebt/OSY		1.74	1.02	1.23	1.00	1.23
Linear HAF		85.4	80.9	84.8	77.5	78.2
Logistical (Ebt)	F1959/	16.8	10.6	15.6	9.3	14.4
	F1959M
Ebt/OSY		1.83	1.05	1.30	1.04	1.32
Dynamic Flame (sec)		30.0	1.1	1.6	1.1	1.6
Manikin Flame	NFPA
Resistance (body	2112
burn rating) (3 sec)	F1930
Tshirt/brief
(50.0 max)
3 Second Exposure
% Total Burn		21.1		55.2	24.9
% 2nd Degree Burn		20.6		35.3	24.6
% 3rd Degree Burn		0.3		19.6	0.3
4 Second Burn
% Total Burn		41.8		69.4	47.8
% 2nd Degree Burn		41.5		25.4	38.5
% 3rd Degree Burn		0.3		44.0	9.3
		Comfort	Comfort	Comfort	PBI
	Properties	Blend-Blue	Blend-Blue	Blend-Denim	Gold	PBI Gold
	Weight, oz/yd2	5.5	6.5	4.5	4.5	6.0
	Nominal
	Weight, oz/yd2Actual	5.59	6.30	4.43	4.56
	Weave	Plain	Twill	Plain	Twill
	Moisture Regain	5.84	5.49	6.53	6.84
	Air Permeability	90.1	74.4	164.9	80.8
	(ft3/ft2/min)
	Elmendorf Tear	2.5 × 3.4	3.1 × 4.3	7.1 × 7.4	31.3 × 32.6
	Resistance(lbf)(W × F)
	Tear Strength	1.9 × 1.3	2.5 × 1.7	5.6 × 4.3	19.2 × 16.6
	(Tongue)(Single Rip)
	Grab Strength (GS)	125.9 × 80.4	157.2 × 109.1	109.7 × 60.1	155.8 × 117.2
	(lbf)(W × F)
	GS After Thermal	4.8 × 3.7	8.6 × 9.6	3.5 × 1.8	20.8 × 16.3
	Exp. (8 sec)
	Tensile, 1-Inch Strip	75.3 × 55.3	89.3 × 57.1	68.2 × 39.6	125.0 × 107.3
	(lbf)(W × F)
	Taber Abrasion	99	179	69	138
	H18 500 gm
	(cycles to failure)
	Laundry Shrinkage(%)
	5X Wash	1.7 × 0.8	1.1 × 1.3	0.5 × 2.0	2.0 × 1.4
	25X Wash	3.3 × 2.7	2.1 × 2.8	5.5 × 2.0	2.9 × 2.9
	Heat and Thermal	3.3 × 3.0	3.0 × 2.6	8.6 × 4.6	1.3 × 1.0
	Shrinkage(%)
	10.0 max
	Flammability
	Original
	Char Length (in)	1.27 × 1.11	1.16 × 1.08	1.48 × 1.40	0.43 × 0.57
	6.0 max
	Afterflame (sec)	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0
	2.0 max
	Afterglow (sec)	0.92 × 0.72	0.88 × 1.16	1.02 × 1.07	20.49 × 16.51
	25X Wash/Dry
	Char Length (in)	1.09 × 0.67	0.84 × 0.90	1.46 × 1.25	0.44 × 0.38
	6.0 max
	Afterflame (sec)	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0	0.0 × 0.0
	2.0 max
	Afterglow (sec)	0.93 × 0.89	1.07 × 0.80	1.41 × 1.39	29.50 × 26.33
	Thermal Protective	11.9	12.5	10.7	11.7	12.9
	Performance (TPP)
	TPP/osy	2.1	2.0	2.4	2.6	2.2
	Preformance (RPP)	7.5	7.9	6.3	7.4	8.1
	ARC FLASH
	TESTING
	Single Layer	5.6	6.4	4.5	4.6	6.0
	wt osy n = 3
	laundering
	Arc Thermal	5.3	6.0	4.8	6.6	7.5
	Performance Linear
	(ATPV)
	ATPV/OSY	0.95	0.94	1.07	1.43	1.25
	Linear HAF	63.3	65.3	60.0	68.3	70.6
	Arc Thermal	5.5	6.2	4.8	6.5	7.9
	Performance Logistical
	(ATPV)
	ATPV/OSY	0.98	0.97	1.07	1.41	1.32
	Single Layer With	10.1	10.9	9.0	9.1	10.5
	nominal 4.5 osy
	Cotton Tshirt
	wt osy n = 3
	laundering
	Linear(Ebt)	11.2	13.1	9.0	14.7 ATPV	17.9 ATPV
					15.8	18.8
	Ebt/OSY	1.11	1.20	1.00	1.62 ATPV	1.70 ATPV
					1.74	1.79
	Linear HAF	82.1	82.6	78.3	83.1	84.9
	Logistical (Ebt)	11.4	13.3	8.9	17.1	19.2 ATPV
						21.6
	Ebt/OSY	1.13	1.22	0.99	1.88	1.83 ATPV
						2.06
	Dynamic Flame (sec)	1.3		1.0	18.7
	Manikin Flame
	Resistance (body
	burn rating) (3 sec)
	Tshirt/brief
	(50.0 max)
	3 Second Exposure
	% Total Burn		20.2	33.9	9.6
	% 2nd Degree Burn		20.2	33.6	9.6
	% 3rd Degree Burn		0.0	0.3	0.0
	4 Second Burn
	% Total Burn		38.3	42.6	37.7
	% 2nd Degree Burn		37.7	38.5	37.7
	% 3rd Degree Burn		0.6	4.1	0.0
	ATPV = arch thermal performance value
	OSY = ounces per square yard
	HAF = heat attenuation factor
	Ebt = energy of break open threshold
	W × F = warp × fill

[0019] The present invention may be embodied in other forms without departing from the spirit and the essential attributes thereof, and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicated the scope of the invention.

Claims

1. A yarn or fabric for use in protective garments comprising: flame resistant fibers selected from the group consisting of inherently flame resistant fibers, treated fibers, and combinations thereof, microdenier flame resistant fibers selected from the group consisting of microdenier inherently flame resistant fibers, microdenier treated fibers, and combinations thereof, and a weight ratio of said flame resistant fibers to said microdenier flame resistant fibers being in the range of 4-9:2-6.

2. The yarn or fabric of claim 1 wherein said inherently flame resistant fibers being selected from the group consisting of aramids, polyamide imides, melamines, polybenzimidazoles, polyimides, polyphenylene benzodisoxazoles, polyphenylene sulfides, polyether ketones, polyetherether ketones, and combinations thereof.

3. The yarn or fabric of claim 1 wherein said microdenier flame resistant fiber having a diameter of less than 10 microns.

4. The yarn or fabric of claim 1 wherein said flame resistant fibers further comprise a blend of inherently flame resistant fibers and treated fibers.

5. The yarn or fabric of claim 4 wherein said weight ratio of inherently flame resistant fibers:microdenier flame resistant fibers:treated fibers is in the range of 1-3:2-6:3-6.

6. A yarn for use in industrial protective garments and having good thermal barrier properties, durability and comfort ratings comprising: 10-30% by weight of the yarn an inherently flame resistant fiber; 20-60% by weight of the yarn a microdenier aramid fiber; and 30-60% by weight of the yarn a treated fiber.

7. The yarn of claim 6 wherein said inherently flame resistant fiber being 15-25% by weight of the yarn.

8. The yarn of claim 6 wherein said inherently flame resistant fiber being selected from the group consisting of aramids, polyamide imides, melamines, polybenzimidazoles, polyimides, polyphenylene benzodisoxazoles, polyphenylene sulfides, polyether ketones, polyetherether ketones, and combinations thereof.

9. The yarn of claim 8 wherein said fiber being a polybenzimidazole.

10. The yarn of claim 6 wherein said microdenier aramid fiber being 45-55% by weight of the yarn.

11. The yarn of claim 6 wherein said treated fiber being 25-35% by weight of the yarn.

12. The yarn of claim 11 wherein said treated fiber being a FR cellulosic.

13. The yarn of claim 12 wherein said FR cellulosic being a FR rayon.

14. The yarn of claim 6 further comprising: 15-25% by weight of the yarn being a PBI staple; 45-55% by weight of the yarn being a microdenier aramid staple; and 25-35% by weight of the yarn being a FR rayon.

15. A fabric for use in industrial protective garments and having good thermal barrier properties, durability and comfort ratings comprising: 10-30% by weight of the fabric an inherently flame resistant fiber, 20-60% by weight of the fabric a microdenier aramid fiber; and 30-60% by weight of the fabric a treated fiber.

16. The fabric of claim 15 wherein said inherently flame resistant fiber being 15-25% by weight of the fabric.

17. The fabric of claim 15 wherein said inherently flame resistant fiber being selected from the group consisting of aramids, polyamide imides, melamines, polybenzimidazoles, polyimides, polyphenylene benzodisoxazoles, polyphenylene sulfides, polyether ketones, polyetherether ketones, and combinations thereof.

18. The fabric of claim 17 wherein said faber being a polybenzimidazole.

19. The fabric of claim 15 wherein said microdenier aramid fiber being 45-55% by weight of the fabric.

20. The fabric of claim 15 wherein said treated fiber being 25-35% by weight of the fabric.

21. The fabric of claim 20 wherein said treated fiber being a FR cellulosic.

22. The fabric of claim 21 wherein said FR cellulosic being a FR rayon.

23. The fabric of claim 15 further comprising: 15-25% by weight of the fabric being a PBI staple; 45-55% by weight of the fabric being a microdenier aramid fiber; and 25-35% by weight of the fabric being a FR rayon.