GB1142253A - Process for the manufacture of crystalline polymer fibres by precipitation from solution and also the polymer fibres thus obtained and the products made therefrom - Google Patents

Abstract

1,142,253. Producing crystalline fibres of organic polymers. STAMICARBON N.V. 2 Jan., 1967 [3 Jan., 1966], No. 141/67. Heading B5B. [Also in Divisions C3 and D2] Crystalline polymer fibres are produced by mechanically agitating a supercooled solution of the polymer, e.g. by stirring the solution at temperatures between 50 and 150‹ C. The polymer may be a homopolymer, copolymer, or block copolymer of one or more alpha olefines, such as ethylene and/or polypropylene. Other polymers which may be used are butene-1, isobutylene, pentene-1, 4-methylpentene-1, styrene, polyoxymethylenes, such as the homopolymers or copolymers of formaldehyde or trioxane, cellulose, polycarbonates and polyamides. Any conventional solvent for the polymer may be used. For poly-alpha-olefines, chlorobenzene, trichlorobenzene, toluene, xylene, perchlorethylene, alpha-chlornaphthalene, tetrahydronaphthalene, decabrydronaphthalene or molten paraffin wax may be used as solvents. The polymer concentration may be between 0À01 and 70% by weight, preferably between 0À1 and 30% by weight. During the agitation of the supercooled polymer solution, bundles or sheets of crystalline polymer fibres are formed and after removal from the solution the fibres are freed from adhering solvent by evaporation thereof or by washing with volatile liquid miscible with the solvent. Electronmicrographs show that the fibres have a characteristic microstructure consisting of a long thin central filament usually provided with lamellar crystals of comparable size which are arranged at fairly regular intervals and extend perpendicularly to the filament. The filament consists of parallel, extended high-polymer chains, while the lamellar crystals consist of folded polymer chains of a lower molecular weight. The fibres obtained are strongly bi-refringent. They may be used for the manufacture of both woven and non-woven fabrics by conventional methods. They can readily be printed and written on and may serve as basic material in the manufacture of paper-like products. In an example, a 5% by weight solution of high-density polyethylene in paraxylene is mechanically stirred for 24 hours at 100‹ C., the stirrer speed being about 150 R.P.M. A loose mass of polymer fibres is obtained. By operating at lower temperature, 100% yield can be obtained.