摘要 |
An oriented elastomeric filament spun from a thermoplastic elastomeric material which is a block copolymer selected from either a block copolymer of polybutylene terephthalate and polytetramethylene glycol; a block copolymer of polybutylene terephthalate/polybutylene isophthalate and polyethylene glycol/polypropylene glycol; a block copolymer of polybutylene terephthalate/polyhexene terephthalate and polytetramethylene glycol; or a block copolymer of polyurethane and polytetramethylene glycol, the mole fraction of said polybutylene terephthalate, polybutylene terephthalate/polybutylene isophthalate and polybutylene terephthalate/polyhexene terephthalate in the respective block copolymer being less than 0.5: and said elastomeric filament being further oriented after said spinning by stretching said elastomeric filament at temperatures between 20<o>C to 120<o>C in a draw ratio producing between 500 to 700 percent elongation of said elastomeric filament so that said oriented elastomeric filament exhibits a two-stage low tensile modulus and high tensile modulus behaviour, when tested in accordance with ASTM D-638 tensile test procedures, such that the high tensile modulus of said oriented elastomeric filament is at least 2 times greater than the low tensile modulus thereof. |