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. 1 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.