Patent ID: 8957183
Filing Date: 2015-02-17
Classification: D01D,D01F,Y10T

Abstract:
1. A yarn comprising copolymer derived from the copolymerization of para-phenylenediamine, 5(6)-amino-2-(p-aminophenyl)benzimidazole, and terephthaloyl dichloride, wherein the ratio of moles of 5(6)-amino-2-(p-aminophenyl)benzimidazole to the moles of para-phenylenediamine is 30/70 to 85/15; said yarn having a sulfur content greater than 0.1%; and the hydrolytic strength retention of the yarn is greater than 60%; wherein the hydrolytic strength retention is computed by dividing the strength of a skein of yarn treated with saturated steam at 150° C. for 24 hours by the strength of an untreated skein of yarn and multiplying by 100.