Process for the polymerization of ethylene or α-olefins and catalyst therefor

Claim 1

A process for the polymerization of ethylene or an α-olefin which comprises polymerizing ethylene or an α-olefin with the use of a catalyst comprising (A) a modified titanium component obtained by the steps of: (1) wet pulverizing a starting titanium component comprising titanium trichloride or its compositions having titanium trichloride as the main component together with an inert organic solvent and a modifier, (2) washing the pulverized products obtained in step (1) with an inert organic solvent and separating the washed products; (3) dry pulverizing the products obtained in step (2), and (4) contacting the pulverized products obtained in step (3) with an inert organic solvent or with a mixture of an inert organic solvent and a modifier, followed by separating the product from the solvent, and (5) in the wet pulverizing of step (1), the dry pulverizing of step (3) or after the washing and separating of step (2), conducting a copulverization treatment together with (a) ethylene or an α-olefin in an amount of about 0.01 to 10% by weight based on said starting titanium component and (b) an organoaluminum compound of the formula AlR.sub.m X.sub.3-m wherein R is an alkyl or aryl group, X is hydrogen or a halogen atom and m is 1 to 3, wherein said modifier in steps (1) and (4) is selected from the group consisting of (i) an oxygen-, sulphur-, phosphor-, nitrogen- or silicon-containing organic compound, (ii) a combination of said organic compound of the item (i) with an aluminum halide, (iii) an organoaluminum compound or (iv) a Lewis acid; and (B) an organoaluminum compound represented by the formula AlR'.sub.m X'.sub.3-m wherein R' is an alkyl or aryl group, X' is hydrogen or a halogen atom and m is 1 to 3.