| 摘要 |
1,154,917. Block polymer-α-olefin-polymer compositions. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 22 Sept., 1966 [24 Sept., 1965], No. 42361/66. Heading C3P. Compositions comprise (1) a block copolymer of formula A-B-A in which each A is an independently selected polymer block of a monovinyl aromatic hydrocarbon, the said polymer block A having an average molecular weight between 8000 and 45,000, and B is a polymer block of a conjugated diene hydrocarbon, the said polymer block A having an average molecular weight between 35,000 and 150,000, the total polymer block A content being less than 38% by weight of the block copolymer and (2), for each 100 parts by weight of the said block copolymer, 15 to 50 parts by weight of a homopolymer of an alpha-olefin having 2 or 3 carbon atoms per molecule. Preferably, the polymer of an alpha-olefin is polyethylene having a density at 23‹ C. between 0À85 and 0À97 grams per cm.<SP>3</SP> and a melt index between 0À2 and 30 at 190‹ C. Other components of the compositions include extending oils and fillers. The compositions may be formed into articles by moulding, and in the examples compositions are formed from (1-2) polystyrene-polybutadiene-polystyrene block polymer, polyethylene, naphthenic extending oil, polystyrene, CaCO 3 , TiO 2 , and nickel dibutyldithiocarbamate; (3) as in (1-2) but omitting the polystyrene; (4) polystyrene-polybutadiene-polystyrene block polymer, naphthenic mineral oil, polyethylene, CaCO 3 , TiO 2 , and zinc stearate; and (5) polystyrene-polybutadiene-polystyrene, and polyethylene. |
