| 摘要 |
PROBLEM TO BE SOLVED: To obtain a propylene-ethylene random copolymer little in a bleedwhitening phenomenon, excellent in low temperature heat sealability, rigidity, and appearance, and useful for films, etc., by copolymerizing propylene with ethylene in a specific catalyst system free from a solvent under a specified condition. SOLUTION: Propylene is copolymerized with ethylene in the presence of a catalyst system comprising (A) a solid catalyst component consisting essentially of magnesium contained in methyl magnesium chloride, etc., titanium contained in titanium trichloride, etc., a halogen and an electron donor such as an alcohol, (B) an organic aluminum compound such as triethyl aluminum, and (C) an electron-donating compound and having an aluminum atom molar ratio of 0.15-1.0 in the components C/B substantially in the absence of a solvent and in a gas phase having an ethylene concentration of 2-5vol.% to produce a propylene-ethylene random copolymer having an ethylene content (E) of 3.5-7.0wt.%, and a xylene-soluble content (D) satisfying the inequality: D<=E+2.0 (wt.%) at 20 deg.C. |
