Patent ID: 7662323
Filing Date: 2010-02-16
Classification: C08F,C08L,D01F,D04H,Y10T

Abstract:
1. A process to produce a bicomponent fiber comprising, a thermoplastic polymer sheath and an elastomeric compound core wherein the elastomeric compound core comprises a selectively hydrogenated block copolymer having an S block and an E or E S-E-S, (S-E a. prior to hydrogenation the S block is a polystyrene block; b. prior to hydrogenation the E block is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a molecular weight from 40,000 to 70,000; c. prior to hydrogenation the E d. n has a value of 2 to 6 and X is the residue of a coupling agent; e. the styrene content of the block copolymer is from 13 to 25 weight percent; f. the vinyl content of the polydiene block prior to hydrogenation is from 70 to 85 mol percent; g. the block copolymer includes less than 15 weight percent of units having the general formula: S-E or S-E h. subsequent to hydrogenation about 0 to 10% of the styrene double bonds have been hydrogenated and at least 80% of the conjugated diene double bonds have been hydrogenated; i. the molecular weight of each of the S blocks is from 5,000 to 7,000; and j. the melt index of the block copolymer is greater than or equal to 12 grams/10 minutes according to ASTM D1238 at 230° C. and 2.16 kg weight, whereby the process comprises coextrusion of a thermoplastic polymer and an elastomeric compound wherein the thermoplastic polymer and the elastomeric compound are forced using separate melt pumps to extrude through a die to form one or more fibers having a sheath primarily consisting of the thermoplastic polymer and a core primarily consisting of the elastomeric compound at a rate of at least 500 meters per minute such that the bicomponent fiber has a denier per filament from 0.1 to 30 grams per 9000 meters.