GB1323296A - Process for the manufacture of synthetic fibres by film fibrillation - Google Patents

Abstract

1323296 Manufacture of synthetic fibres by film fibrilation SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 6 Jan 1971 [8 Jan 1970] 970/70 Heading B5B A process for the manufacture of synthetic fibres from films of thermoplastic polymeric material, in which (a) three or more films of the same composition and structure, (b) two or more films of different composition and/or structure, or (c) one or more multicomponent films consisting of two or more layers of different and not permanently compatible materials are subjected, whilst the films or film layers are in stretched state and in juxtaposition above each other, to a mechanical fibrillation treatment to fibrillate the films or film layers simultaneously using the same mechanical means. Preferably the stetched films originate from the same stretching unit and each of the films of the same composition and structure to be processed simultaneously is integrally joined by one or more longitudinal folds to the next film or films. In a particularly preferred embodiment the films to be processed simultaneously originate from laying flat a blown film produced by an extrusion process, during the blowing step whereof at least one gusset is employed. The mechanical treatment to which the stretched films or film layers are simultaneously subjected may be any known fibrillation method employing mechanical means, e.g. rubbing, cutting, brushing or exposure to a gas jet or a rapid stream of solid particles or preferably by drawing stretched films or film layers over a cylinder provided with pins which is rotating more rapidly than the film in the same direction. Particularly preferred are pins arranged in rows parallel to the cylinder axis. The so obtained product is suitable in further working up, e.g. in preparing soft twines by stretch-breaking. Suitable thermoplastic polymeric materials include homo- and copolymers of vinylchloride, vinylidene chloride, vinyl acetate, acrylontrile as well as polyesters and polyamides. Preferred materials comprise homo- and copolymers of pivololactone and of lower olefins, preferably polypropylene and low pressure polyethylene. Preferably the thickness of each film or film layer in unstretched form is less than 50 microns, especially 20-35 microns.