| 摘要 |
A polyethylene composition comprising three specific types of polyethylenes; polyethylene (A), polyethylene (B) and polyethylene (C) respectively. The polyethylene composition has a melt index not less than 0.001 g/10 min. and not more than 10 g/cm and exhibits excellent processability under variant molding techniques. Molded objects exhibit excellent physical properties such as impact strength environmental stress cracking resistance and uniform thickness distribution. Polyethylene (A) has a molecular weight of from 5,000 to 90,000 and polyethylene (C) has a molecular weight of from 100,000 to 1,500,000 and the ratio of the molecular weight of polyethylene (C)/the molecular weight of polyethylene (A) is from 4 to 200. Polyethylene (B) has a molecular weight of from 50,000 to 500,000, being prepared by a polymerization with use of a chromium compound-supported type catalyst capable of producing a specifically conditioned homopolyethylene with respect to the properties of the polymers in terms of flow ratio and die swell. |
