| 摘要 |
PURPOSE:A propylene-ethylene random copolymer having a specific melt index and a specific ethylene content is combined with a specific amount of a nucleating agent and an organic peroxide, then the composition is heat-treated until its decomposition reaches a prescribed degree to improve the clarity and toughness of the copolymer. CONSTITUTION:(A) 100pts.wt. of a propylene-ethylene copolymer with a melt index of 5-30g/10min., preferably 6-15g/10min. and an ethylene content of 0.5-5wt%, preferably 1-1wtk% are combined with (B) 0.01-1pt.wt., preferably 0.05-0.5pt.wt. of a nucleating agent, preferably a sorbitol derivative and talc of 0.5-10 micrometer average particle size and (C) 0.001-0.2pt.wt., preferably 0.01-0.1pt.wt. of an organic peroxide such as 1,3-bis(t-butylperoxy-isopropyl) benzene in such an amount as the degree of decomposition at 170-300 deg.C reaches 1.1-6, preferably 2.5-5, then the resultant composition is heat-treated.
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