Limited-antimony-content and antimony-free modacrylic / aramid blends for improved flash fire and arc protection
View Patent ↗A yarn, fabric, and garment suitable for use in arc and flame protection comprising aramid fiber and modacrylic fiber wherein the modacrylic fiber has less than 1.5 percent antimony and is preferably antimony-free. In one embodiment, the yarn, fabric, and/or garments consist essentially of (a) 50 to 80 weight percent meta-aramid fiber having a degree of crystallinity of at least 20%, (b) 10 to 40 weight percent modacrylic fiber that is antimony-free, (c) 5 to 20 weight percent para-aramid fiber, and (d) 1 to 3 weight percent antistatic fiber, based on the total weight of components (a), (b), (c) and (d). In some embodiments, garments made from the yarns provide thermal protection such that a wearer would experience less than a 65 percent predicted body burn when exposed to a flash fire exposure of 4 seconds per ASTM F1930, while maintaining a Category 2 arc rating per ASTM F1959 and NFPA 70E.
1. A yarn for use in arc and flame protection comprising aramid fiber and modacrylic fiber wherein the modacrylic fiber has less than 1.5 percent antimony;
wherein, the yarn contains:
(a) 50 to 80 weight percent meta-aramid fiber having a degree of crystallinity of at least 20%;
(b) 10 to 40 weight percent modacrylic fiber;
(c) 5 to 20 weight percent para-aramid fiber.
2. The yarn of claim 1 wherein the modacrylic fiber has less than 1 percent antimony.
3. The yarn of claim 2 wherein the modacrylic fiber is antimony-free.
4. The yarn of claim 3 further comprising an antistatic fiber.
5. The yarn of claim 3 consisting essentially of:
(a) 50 to 80 weight percent meta-aramid fiber having a degree of crystallinity of at least 20%;
(b) 10 to 40 weight percent modacrylic fiber;
(c) 5 to 20 weight percent para-aramid fiber; and
(d) 1 to 3 weight percent antistatic fiber;
said percentages on the basis of components (a), (b), (c), and (d).
6. A fabric suitable for use in arc and flame protection comprising aramid fiber and modacrylic fiber wherein the modacrylic fiber has less than 1.5 percent antimony; the fabric having a basis weight of 135 to 407 grams per square meter (4.0 to 12 ounces per square yard);
wherein, the fabric comprises a yarn which contains:
(a) 50 to 80 weight percent meta-aramid fiber having a degree of crystallinity of at least 20%;
(b) 10 to 40 weight percent modacrylic fiber;
(c) 5 to 20 weight percent para-aramid fiber.
7. The fabric of claim 6 wherein the modacrylic fiber has less than 1 percent antimony.
8. The fabric of claim 6 wherein the modacrylic fiber is antimony-free.
9. The fabric of claim 8 further comprising an antistatic fiber.
10. The fabric of claim 8 comprising a yarn consisting essentially of:
(a) 50 to 80 weight percent meta-aramid fiber having a degree of crystallinity of at least 20%;
(b) 10 to 40 weight percent modacrylic fiber;
(c) 5 to 20 weight percent para-aramid fiber; and
(d) 1 to 3 weight percent antistatic fiber;
said percentages on the basis of components (a), (b), (c), and (d); the fabric having a basis weight of 150 to 290 grams per square meter (4.5 to 8.5 ounces per square yard).
11. The fabric of claim 8 having arc resistance according to ASTM F-1959-99 of at least 1.5 calories per square centimeter per ounce per square yard of fabric.
12. The fabric of claim 8 further comprising a nylon fiber.
13. The fabric of claim 12 having arc resistance according to ASTM F-1959-99 of at least 1.7 calories per square centimeter per ounce per square yard of fabric.
14. A garment comprising the fabric of claim 11 providing thermal protection equivalent to less than a 65% body burn at a 4 sec flame exposure per ASTM F1930, while maintaining a Category 2 arc rating per ASTM F1959 and NFPA 70E.
15. A garment comprising the fabric of claim 13 providing thermal protection equivalent to less than a 65% body burn at a 4 sec flame exposure per ASTM F1930, while maintaining a Category 2 arc rating per ASTM F1959 and NFPA 70E.