NOVEL ELASTIC FIBERS, AN ASSEMBLY THEREOF, AND PROCESS FOR PRODUCTION OF SAID ASSEMBLY

摘要

An elastic fiber having improved elastic properties has the following properties: (a) each elastic fiber is composed of at least two thermoplastic polymers, (b) at least one of the thermoplastic polymers has crystallinity capable of forming a row structure. (c) at least one other of the thermoplastic polymers has crystallinity capable of forming lamellar crystalls, and (d) each elastic fiber has a row structure. These fibers can form an elastic fibrous assembly. The assembly, which can be used as a material for clothes, can be produced by extruding a combined polymer melt of at least two thermoplastic polymers including polymers (b) and (c) through a mesh spinneret (7) including many closely arranged small openings and having an opening ratio ( alpha ) of at least 10%. Extrusion is carried out while generating Joule heat in the partitioning members of the spinneret, for example by supplying electric current through copper plates (8) to the spinneret (7). The vicinity of the extrusion surface of the spinneret is cooled by supplying a cooling fluid such as air from a feed device (11). The melt is converted into fine streams by the partitioning members. The solidified fine streams (13) are taken up, for example by a take-up roller (12), and are heat-treated by suitable means (14).