| 摘要 |
1328102 Copolymers IMPERIAL CHEMICAL INDUSTRIES Ltd and BRITISH INSULATED CALLENDERS CABLES Ltd 3 Sept 1970 [11 Sept 1969] 45000/69 Heading C3P Crystalline polymeric compositions having a melt flow index of 0À01 to 0À5 (2À16 kg at 230‹ C),. containing 10 to 30 weight per cent of ethylene and comprising (1) at least one sequence of propylene homopolymerized or copolymerized with up to 10 weight per cent of another olefin and (2) at least one sequence of propylene copolymerized with ethylene, are prepared by sequential polymerization in the presence of a titanium trichloride/organo-aluminium catalyst. The other olefin may be ethylene or butene-1, and the polymerization may be effected in the presence of hydrogen. To provide sequence (2) the ethylene may be injected in a single shot. The catalyst may comprise a dialkyl aluminium halide and the product obtained by reducing titanium tetrachloride with a dialkyl aluminium halide. The copolymers may be blended with conductive carbon black, and may be used for covering cables and conductors. Examples describe (1-4) the preparation of polypropylene/ propylene-ethylene copolymer, block copolymers stabilized with 1,1,3-tris(2<SP>1</SP>-methyl-5<SP>1</SP>-t-butyl- 4<SP>1</SP>-hydroxyphenyl) butane and dilauryl thiodipropionate. |
