Block copolymer composition and its production

Abstract

Abstract PURPOSE:To obtain a block copolymer composition excellent in impact resistance, rigidity and flow during molding, by copolymerizing a monomer mixture of ethylene and propylene in the presence of a highly stereoregular polymerization catalyst in three stages wherein different reactant ratios are used. CONSTITUTION:A monomer mixture of ethylene and propylene is polymerized at an ethylene/propylene ractant ratio in the range of 2/98-0/100 (by weight) in the presence of a highly stereoregular polymerization catalyst (e.g., a combination of TiCl3 and diethylaluminum chloride) until the amount of the polymer formed reaches 70-90wt% of the total polymer weight to be produced. Then, polymerization is effected at an ethylene/propylene reacant ratio of 30/70-60/ 40 (by weight) until the amount of the polymer formed reaches 1-8wt% of the total polymer to be produced. Further, polymerization is carried out at an ethylene/propylene reactant ratio of 60/40-95/5 (by weight) until the amount of the polymer formed reaches 8-29wt% of the total polymer to be produced. The above polymerization is carried out by controlling the MW so that the limiting viscosities of the polymers become higher in order of the steps.

Inventors

• 👤 Tadashi Asanuma
• 👤 正 浅沼
• 👤 Ichiro Fujikage
• 👤 一郎 藤隠
• 👤 Shinryu Uchikawa
• 👤 進隆 内川
• 👤 Tetsunosuke Shiomura
• 👤 潮村　哲之助

Bibliographic Details