Ethylene copolymer and process for producing the same, resin composition containing the copolymer, and uses of these

Abstract

The present invention is intended to provide an ethylene copolymer having excellent mechanical properties and moldability. The copolymer comprises 40 to 99% by mol of ethylene constituent units and 1 to 60% by mol of C3-20 alpha-olefin constituent units; the ratio (Mz / Mw) of a Z average molecular weight (Mz) to a weight-average molecular weight (Mw), each molecular weight being measured by GPC, is in the range of 10 to 30, and said ratio (Mz / Mw) and the ratio (Mw / Mn) of a weight-average molecular weight (Mw) to a number-average molecular weight (Mn), each molecular weight being measured by GPC, satisfy the relation (Mz / Mw); the intrinsic viscosity is in the range of 0.5 to 4 dl / g; the ratio (n*0.01 / n*8) of a melt viscosity (eta*0.01) at a shear rate of 0.01 rad / sec, as measured at 190 DEG C., to a melt viscosity (eta*8) at a shear rate of 8 rad / sec, as measured at 190 DEG C., and the intrinsic viscosity (eta) satisfy the relation (eta*0.01 / eta*8)>=0.843x(eta)+1.0; and the absolute value of an activation energy (Ea) of a shift factor of melt viscoelasticity is not more than 4x10<4> J / mol.K.

Description

technical field [0001] The present invention relates to an ethylene copolymer, its use and a process for its preparation. The present invention also relates to a resin composition containing the ethylene copolymer and its use. Background technique [0002] Ethylene copolymers (such as ethylene / α-olefin copolymers) are useful, for example, in hollow containers, pipes, films, foamed articles, and rubber. Ethylene copolymers are required to have excellent extrusion properties and bubble stability in inflation molding, and to have excellent moldability (fluidity) capable of high-ratio expansion in foam molding. In addition, when an ethylene copolymer is used as a resin modifier, it is required to have an excellent effect of improving mechanical properties such as breaking strength and impact resistance of molded articles. [0003] Therefore, some proposals have been made to obtain ethylene copolymers having excellent moldability and enabling molded articles to have excellent m...

AI Technical Summary

Problems solved by technology

[0004] For example, a method of blending high-molecular-weight ethylene copolymers with low-density polyethylene produced by high-pressure polymerization can improve moldability, but the problem is that the resulting molded articles become hard or opaque, resulting in poor feeling

[0005] A method of irradiating ethylene copolymers with electron beams or adding organic peroxides to partially crosslink ethylene copolymers to form long-chain branches improves moldability, but has the problem of producing gels

[0006] A method of broadening the molecular weight of an ethylene copolymer improves moldability (such as film moldability), but leads to an increase in the content of low-molecular-weight components, resulting in a decrease in mechanical properties, or the resulting molded article has developed sticky surface