Patent ID: 6573343
Filing Date: 2003-06-03
Classification: C08F,Y10S

Abstract:
A process for the preparation of an olefin polymer, said process comprising polymerising at least one olefin in the presence of an olefin polymerisation multisite catalyst in two reaction stages, hydrogen being present at a higher concentration in one reaction stage and a lower concentration in the other reaction stage, said olefin polymerisation multisite catalyst having:(I) a metallocene catalytic site A capable of producing a different polymer component at said higher and lower hydrogen concentrations, the MFR2 of the polymer produced during the higher hydrogen concentration reaction stage being 100 to 2000; and (II) a catalytic site B capable of producing a different polymer component at said higher and lower hydrogen concentrations; such that the ratio of the MFR2 of the polymer components produced by catalytic site A is at least 50 and the ratio of the MFR2 of the polymer components produced by catalytic site B is less than 10.