| abstract |
This new catalyst for polymerisation of alpha-olefins is obtd. by using a solid catalyst (1) having two components in the prepolymerisation process of alpha-olefins. The solid catalyst (1) comprises (A) a solid catalyst component in which a transition metal cpd. is provided on a carrier and (B) an aluminoxane. The transition metal cpd. is specified to be cpd. of Ti, Zr or Hf and has the general formula R1kR2lR3mR4nMe (I), where R1 is cycloalkadienyl gp.; R2, R3 and R4 are the same or different and are cycloalkadienyl, aryl, alkyl, aralkyl, halogen atoms, H, ORa, SRb, SRb or NRc2 (where Ra, Rb and Rc are alkyl, cycloalkyl, aryl gps. etc.); Me is Zr, Ti or Hf; k=1, 2, 3 or 4; l, m, n=0, 1, 2 or 3; and k+l+m+n=4. The aluminoxane has the general formula (II) or (III) where R is a hydrocarbon gp. X is a halogen atom; a and b are independently numbers between 0 and 80, but not both 0 at the same time. The carrier is treated with organometal cpds., e.g. organo-aluminium, boron, Mg, Zn or Li before the transition metal cpd. is provided on it. Porous inorganic oxide cpds. are used as carriers. The alpha-olefin is polymerised or copolymerised in the presence of the above mentioned catalyst. The alpha-olefin has a carbon number between 2 and 20. Ethylene can be added during the copolymerisation of 3-20C alpha olefins. |