| 摘要 |
A bulky yarn-like structure is made by fibrillating a strand consisting of or containing a synthetic organic polymer by the beating action of a fluid flowing in a highly turbulent stream at high velocity while the strand is kept slack or under a very low tension. The product is in the form of a bundle of fibres, at least some of which are shorter than the length of the bundle. The strand is preferably a strip of film, the material of which has been rendered fibrillatable by drawing the film lengthwise until the film material has been highly oriented in this direction. The fluid may be a liquid but is preferably a gas such as air introduced at least 1/2 sonic velocity into a passageway through which the strip is advanced. The polymer may be a polyethylene, a polyacrylonitrile, a polyamide, a polyethylene terephthalate, a polyurethane, a copolymer of 94 parts of acrylonitrile and 6 parts of methyl acrylate or a 70/30 mixture of polyacrylonitrile and tetramethylene sulphone. A list of other polymers which may be used is given. The turbulence and treatment conditions may be so controlled that the fibrils of the structure remain connected to form an integral network, or the fibrillated strand may be subjected to a beating action vigorous enough to tear some of the fibrils to produce loose ends. The fibrillatability of the strands may be increased by selecting for the strand material a blend of two polymers or copolymers which, whether chemically related or not, are only partially compatible. More than one strand of the fibrillatable material comprising the same or different polymers may be subjected to the treatment in the same turbulent zone. One or more non-fibrillatable strands, such as a yarn or a bundle of continuous filaments, may be led through the zone of turbulence together with the fibrillatable strand or strands. In an example, a film of a linear polyethylene 0,1 mil. thick and 1/16 inch wide, which has been drawn at 90 DEG C. to 12 times its original length, is passed at about 30 feet per minute through a cylindrical passageway into which leads an air passageway whose axis intersects that of the yarn passageway at an angle of about 45 degrees and is inclined forward in the direction of travel of the yarn. Air at 40 p.s.i. pressure is introduced into the air passageway so that the narrow strip of film is passed through a stream of air travelling concurrently with the strip at high velocity. The structures of the invention have the warmth and appearance of staple spun yarn but substantially higher strength. U.S.A. Specification 2,852,906 is referred to.
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