| 摘要 |
A continuous process for preparation of propylene-ethylene block copolymer suitable for moldings with high rigidity and high impact resistance are provided, which process is a continuous process for preparation of highly rigid propylene-ethylene block copolymers, wherein propylene and ethylene are polymerized in the specified 2 steps with use of a catalyst system comprising (A) a solid catalyst component containing Ti, Mg, halogen and polyvalent carboxylic ester, (B) an organic aluminium compound, as well as (C) an organic silicon compound expressed by the general formula R4xR5ySi(OR6)z (wherein, x+y+z=4), and wherein the ratio between the maximum value and the minimum value of MFR(l)) is 0.1</=Log(MFR(h)/MFR(l))</=1, and the ratio between the average MFR(i) and MFR(ii) in the subsequent polymerization procedure (II) containing ethylene in a relatively large amount which is carried out by adding the glycol type compound is 3</=Log(MFR(i)/MFR(ii))</=7. The product having less fish eye and high impact resistant value was obtained from the copolymer according to the invention.
|
