Patent ID: 6225251
Filing Date: 2001-05-01
Classification: C08F,Y10S

Abstract:
A metallocene catalyst supported on an alumoxane-treated silica comprising:a) a metallocene compound of the general formulaR"".sub.b (C.sub.5 R.sub.b-5) (C.sub.5 'R'.sub.b-5)MR*.sub.v-2where R"" is a bridge imparting stereorigidity to the structure to the metallocene by connecting the two cyclopentadienyl rings, b is 1 or 0 indicating whether the bridge is present or not, C.sub.5 is a cyclopentadienyl ring, R and R' are substituents on the cyclopentadienyl rings and are a hydride or a hydrocarbyl from 1-9 carbon atoms, each R and R' being the same or different, M is a Group 3, 4, 5 or 6 metal, R* is a hydride, a halogen or a hydrocarbyl from 1-20 carbon atoms, v is the valence of M;b) an alumoxane-treated silica;wherein the metallocene compound has been supported on the alumoxane-treated silica at a temperature maintained in the range of -20.degree. C. to 0.degree. C. during the course of the reaction between a) and b).