| 摘要 |
1,159,216. Staple fibre. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 27 July, 1967 [29 July, 1966], No. 34534/67. Heading B5B. [Also in Division D1] Staple fibres are produced from films of thermoplastic polymers by stretching a strip of the film transversely to the direction of movement, at a stretching ratio sufficiently high (having regard to the stretching temperature) to render the film fibrillatable, subsequently cutting the stretched film into secondary strips, the longitudinal direction of which coincides with the direction of movement, and splitting the secondary strips into fibres. The film is preferably a polyolefin of at least 50% crystallinity, polypropylene or polyethylene being particularly suitable. The transverse stretching of the film and subsequent fibrillation are effected by methods known in the art. During the process stretching of the film in the direction of movement can be counteracted by transverse stretching of a corrugated film, by suitable arrangement of the clamps used to effect transverse stretching, or by providing transverse slits and scratches in the film before or simultaneously with the transverse stretching. If desired, the film strip before being cut into secondary strips, can be subjected to treatments such as stabilizing, finishing or crimping.
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