| 摘要 |
PURPOSE:To obtain the titled copolymer, a thermoplastic elastomer outstanding in strength, heat resistance and low-temperature impact resistance, by making a copolymer constituted of propylene homopolymer block and ethylene-propylene copolymer blocks using a specific catalyst followed by crosslinking with a crosslinking agent. CONSTITUTION:First, an olefin block copolymer constituted of (A) 15-45wt.% of propylene homopolymer block, (B) 5-25wt.% of ethylene-propylene two- component random copolymer block containing 3-20wt.% of ethylene, and (C) 50-70wt.% of ethylene-propylene two-component random copolymer block containing 20-40wt.% of ethylene with the component A accounting for 50-90wt.% of the components A plus B is made using a Ziegler type catalyst comprising (1) a solid composition comprising Mg, Ti and halogen as the essential components, respectively, (2) an electron donor and (3) an organoaluminum compound. Thence, this copolymer is crosslinked while kneading at <=230 deg.C together with an organic peroxide, divinyl compound and antioxidant, thus obtaining the objective copolymer with the content of hot-xylene insolubles 5-40wt.%.
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