GB1053916A - - Google Patents

Abstract

1,053,916. Self-crimping composite filaments. MONSANTO CO. Feb. 1, 1965 [Feb. 17, 1964], No. 4247/65. Heading B5B. [Also in Division D1] Self-crimping composite filaments are made by simultaneously spinning through a common orifice at least two diverse synthetic polymers to form a composite filament in which the components are eccentrically disposed, said components being heat-settable, one of them having a lower stretch-orientability and higher residual shrinkage than another of the components, then drawing the filament to thereby selectively orient the component having the higher stretch-orientability while allowing the other of the components to remain unoriented and non-crystallized, then heating the filament while in a relaxed state to simultaneously induce a differential shrinkage and setting of the components in a crimped configuration and finally cooling the crimped filament to impart to it crimp retractive forces of a magnitude sufficient to overcome inter-filament fabric friction. The component having a higher stretchorientability is a heat-settable homopolyamide and the component having a lower stretchorientability is a heat-settable copolyamide which may be a non-isomorphous disordered copolyamide. The filament may have its crimp temporarily removed so that the yarn can be wound compactly upon a bobbin. The homopolyamide may be polyhexamethylene adipamide and the copolyamide may be that polymer copolymerized with polyhexamethylene sebacamide, polyhexamethylene isophthalamide or polyhexamethylene dodecanoamide. The heat relaxing step may be effected by passing the filament through an atmosphere of steam under a tension sufficiently reduced to allow the filament to relax at least 20%. Alternatively it may be effected by passing the filament through a jet of heated fluid whereby the filament is allowed to undergo independent random reversals of crimp.