| 摘要 |
PROBLEM TO BE SOLVED: To provide an ethylenic copolymer having narrow molecular weight distribution and branching distribution and controlled compositional distribution profile and giving a film having especially excellent mechanical properties such as tear strength and impact strength, heat-sealability and environmental stress cracking resistance and provide a method for producing the copolymer. SOLUTION: The ethylenic copolymer has an Mw/Mn ratio of 1.5-4.0 and an Mw of 3,000-1,000,000 measured by GPC technique, satisfies the relationship 0.704+0.147n<=W/2<=-0.055+0.577n wherein W/2 is the half width at half maximum of the curve obtained by the Gaussian approximation of the main peak of a compositional distribution curve obtained by temperature-increasing fractionation and (n) is the average number of short branches of the polymer and has a resin density of 0.85-0.95 g/cm<3> . The present invention further relates to a method for producing the copolymer and an ethylenic copolymer composition containing the copolymer.
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