| 摘要 |
1,213,442. Polyolefin films and fibres. HERCULES INC. 2 Jan., 1969 [2 Jan., 1968; 19 Nov., 1968], No. 373/69. Heading B5B. [Also in Divisions B2, C3, F2 and H1] Films and fibres may be prepared by shaping compositions comprising (1) a crystallizable olefin polymer having an intrinsic viscosity of at least 2, in the form of particles of average primary particle size 0À02 to 0À5 micron, with at least 75 per cent of the particles in the range 0À2 to 0À4 micron with substantially no irreducible clusters of particles greater than 5 microns, and (2) 50 to 1900 weight per cent based on the olefin polymer of a solid, particulate, inorganic filling material which is insoluble in the olefin polymer, is solid at the melting temperature of the polymer and is in the form of particles of size 0À1 to 25 microns. Preferably the composition is shaped as a dispersion in an inert hydrocarbon diluent and the polymer subsequently fused. Films may be formed by casting on chromium plate, e.g. chromium plated brass, and the films may be oriented in one or more directions by stretching or cut into strips which may be stretched to produce monofilaments. The polymer may be polypropylene, an ethylene/propylene copolymer or a polymer of higher olefins, styrene or substituted styrenes. The filler may be molybdenum disulphide, barium titanate, titanium dioxide, calcium carbonate, silica, clay, carbon black, copper, zinc, sodium chloride, iron oxide, zinc oxide or aluminium flake. In examples films are cast from compositions comprising polypropylene, kerosene and (2) zinc oxide; (4) calcium carbonate, which films are (5) biaxially stretched 4 Î ; (10) iron oxide, titanium dioxide and maleic modified polypropylene, the films being cut into strips and stretched 4 Î to form monofilaments; (11) aluminium flake; and (17) barium titanate, maleic modified polypropylene, distearyl thiodipropionate and phenolic antioxidant. |
