Thermal camouflage fabric with flame resistant properties

Abstract

A yarn is disclosed, including a blend of: 33-75 wt. % of a flame resistant fiber having a limit of oxygen index of 43%, a thermal conductivity of 0.0044 watt/meter/K and a moisture regain of 12%; 10-40 wt. % of an aramid fiber; and up to 36% of a wearability enhancing fiber selected from wool, flame resistant rayon and lyocell. The yarn is: (a) free of thermoplastics; (b) sufficiently flame resistant such that a fabric consisting of the yarn is effective to limit a body burn percentage resulting from 4 seconds of flame exposure to less than 35% as measured by ASTM F1930; and (c) sufficiently opaque to infrared light such that a measured temperature difference is less than 5° C. between a background at 22° C. and a 250 g/m2 fabric of the yarn on a 37° C. body. Flame resistant and thermal camouflage fabrics and garments including the inventive yarn are also disclosed.

What is claimed is: 
     
         1 . A yarn comprising a blend of:
 33-75 wt. % of a flame resistant fiber having a limit of oxygen index of 43%, a thermal conductivity of 0.0044 watt/meter/K and a moisture regain of 12%;   10-40 wt. % of an aramid fiber; and   up to 36% of a wearability enhancing fiber selected from the group consisting of wool, flame resistant rayon and lyocell,   wherein the yarn is:   free of thermoplastics;   sufficiently flame resistant such that a fabric consisting of the yarn is effective to limit a body burn percentage resulting from 4 seconds of flame exposure to less than 35% as measured by ASTM F1930; and   sufficiently opaque to infrared light such that a measured temperature difference is less than 5° C. between a background at a background temperature of 22° C. and a 250 g/m 2  fabric of the yarn placed on a body at a body temperature of 37° C.   
     
     
         2 . The yarn of  claim 1 , wherein the yarn is sufficiently flame resistant such that the fabric consisting of the yarn is effective to limit the body burn percentage resulting from 4 seconds of flame exposure to less than 15% as measured by ASTM F1930. 
     
     
         3 . The yarn of  claim 1 , wherein the flame resistant fiber is PYROTEX. 
     
     
         4 . The yarn of  claim 3 , wherein the aramid fiber is a para-aramid fiber and the wearability enhancing fiber is wool. 
     
     
         5 . The yarn of  claim 4 , comprising 49-51 wt. % of the flame resistant fiber, 29-31 wt. % of the aramid fiber and 19-21 wt. % of the wearability enhancing fiber. 
     
     
         6 . The yarn of  claim 4 , wherein the para-aramid is TWARON or KEVLAR. 
     
     
         7 . The yarn of  claim 1 , which is free of cellulosic fibers. 
     
     
         8 . The yarn of  claim 1 , further comprising an electrostatic dissipative fiber. 
     
     
         9 . A fabric comprising the yarn of  claim 1 , wherein the fabric is: (a) free of thermoplastics; (b) effective to limit the body burn percentage resulting from 4 seconds of flame exposure to less than 35% as measured by ASTM F1930; and (c) sufficiently opaque to infrared light such that the measured temperature difference is less than 5° C. between the background at the background temperature of 22° C. and a 250 g/m 2  sample of the fabric placed on the body at the body temperature of 37° C. 
     
     
         10 . A garment comprising the yarn of  claim 1 , wherein the garment is: (a) free of thermoplastics; (b) effective to limit the body burn percentage resulting from 4 seconds of flame exposure to less than 35% as measured by ASTM F1930; and (c) sufficiently opaque to infrared light such that the measured temperature difference is less than 5° C. between the background at the background temperature of 22° C. and the garment when worn by a person whose body temperature is 37° C. 
     
     
         11 . A fabric comprising a blend of:
 33-75 wt. % of a flame resistant fiber having a limit of oxygen index of 43%, a thermal conductivity of 0.0044 watt/meter/K and a moisture regain of 12%;   10-40 wt. % of an aramid fiber; and   up to 36% of a wearability enhancing fiber selected from the group consisting of wool, flame resistant rayon and lyocell,   wherein the fabric is:   free of thermoplastics;   effective to limit a body burn percentage resulting from 4 seconds of flame exposure to less than 35% as measured by ASTM F1930; and   sufficiently opaque to infrared light such that a measured temperature difference is less than 5° C. between a background at a background temperature of 22° C. and a 250 g/m 2  sample of the fabric placed on a body at a body temperature of 37° C.   
     
     
         12 . The fabric of  claim 11 , wherein the fabric is effective to limit the body burn percentage resulting from 4 seconds of flame exposure to less than 13% as measured by ASTM F1930. 
     
     
         13 . The fabric of  claim 11 , wherein the flame resistant fiber is PYROTEX. 
     
     
         14 . The fabric of  claim 13 , wherein the aramid fiber is a para-aramid fiber and the wearability enhancing fiber is wool. 
     
     
         15 . The fabric of  claim 14 , comprising 49-51 wt. % of the flame resistant fiber, 29-31 wt. % of the aramid fiber and 19-21 wt. % of the wearability enhancing fiber. 
     
     
         16 . The fabric of  claim 14 , wherein the para-aramid is TWARON or KEVLAR. 
     
     
         17 . The fabric of  claim 11 , which is free of cellulosic fibers. 
     
     
         18 . The fabric of  claim 11 , further comprising an electrostatic dissipative fiber.