GB1053596A - - Google Patents

Abstract

1,053,596. Block polymer compositions. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. June 28, 1965, No. 27259/65. Heading C3P. A composition comprises a minor amount of (1) a block polymer (A-B) n or (A-B) n - A in which n is a positive integer, block A consists of a polymerized vinyl aromatic compound not more than 25% of the benzenoid double bonds of which are hydrogenated and block B is an elastomeric block containing substantially no unsaturation or a polymerized conjugated diene at least 75% of which is hydrogenated, and a major amount of (2) a polymer of a vinyl aromatic compound or compounds and/or a polymer of a vinylidene aromatic compound or compounds. Specified block polymers are hydrogenated polystyrene - polyisoprene - polystyrene, polystyrene - polyisobutylene - polystyrene, polystyrene - polyether - polystyrene, in which the polyether is polymerized ethylene oxide and/or propylene oxide or a copolymer of such an oxide with ethylene sulphide or propylene sulphide, and polystyrene-ethylene/ butylene copolymer-polystyrene. Preferably 10 to 25% of the block polymer, or polymers, is blended with polymer (2) which may be a polymer of styrene, an alkyl, dialkyl or halo nuclearly substituted styrene or a copolymer thereof with a minor amount of a vinylidene aromatic compound, e.g. α-methyl styrene. Lubricants, e.g. butyl stearate and mineral white oil, pigments, antistatic agents and antioxidants may be incorporated. In the example a polystyrene-polyisoprene-polystyrene block polymer in which the polyisoprene block is substantially hydrogenated is blended with a polystyrene containing butyl stearate. Zinc stearate, zinc oxide and an antioxidant are included in the blend.