Flame-retardant, vapor-permeable waterproof structure

Claim 1

A flame resistant copolyetherester elastomer film composition comprising (a) 60-85 weight percent of a hydrophilic copolyetherester elastomer film having a thickness of 0.3-1.6 mils, a water vapor transmission rate of at least 6,000 gm.mil/m 2/ 24 hours and an elongation of at least 600% with said hydrophilic elastomer film consisting essentially of a multiplicity of long chain ester units and short chain ester units joined head-to-tail through ester linkages, said long chain ester units being represented by the formula ##STR7## and said short chain ester units represented by the formula ##STR8## where G is a divalent radical remaining after the removal of terminal hydroxyl groups from a poly(alkylene oxide)glycol having an average molecular weight of about 400-3500 and, further, the poly(alkylene oxide)glycol contains sufficient units of ethylene oxide to incorporate in the resulting copolyetherester from about 25-68 weight percent units of ethylene oxide based on the total weight of the copolyetherester elastomer; R is a divalent radical remaining after the removal of carboxyl groups from a dicarboxylic acid having a molecular weight less than 300; D is a divalent radical remaining after the removal of hydroxyl groups from a diol having a molecular weight less than 250; the copolyetherester elastomer contains about 25-80 weight percent short chain ester units, and (b) 15-40 weight percent of a flame retardant component comprised of 37.5 to 100 weight percent of a brominated aromatic compound selected from the group consisting of tetradecabromodiphenoxybenzene, ethylenebistetrabromophthalimide, and decabromodiphenoxybenzene, wherein the weight percents for component (a) and component (b) are based upon the weight of (a) and (b) only and provided that the ratio of the film thickness, in mils, to the weight percent of the brominated aromatic compound, as based upon the weight of (a) and (b), is less than about 0.04.