Patent ID: 7026265

Claim:
A process for the preparation of a particulate olefin polymerisation catalyst component comprising a magnesium dihalide, a titanium tetrahalide and carboxylic acid ester, comprising the steps: i) providing a magnesium compound continuing at least one alkoxy group; ii) reacting said magnesium compound in a solution of a C 6 –C 10 aromatic solvent, with a halide of a carboxylic acid and a tetravalent titanium compound containing halogen to obtain a dissolved reaction product wherein the solution also contains a C 2 –C 12 polyhydric alcohol and a reactive halogenated C 1 –C 20 hydrocarbon; iii) initiating in said solution the formation of one or more oligoesters of said carboxylic acid with said polyhydric alcohol by adding a quantity of an apolar solvent insufficient to cause precipitation of the reaction product of ii); iv) continuing the oligoester formation until the resultant change in the composition of the solution phase causes co-precipitation of said one or more oligoesters and of said reaction product; and v) recovering washing and drying the co-precipitate to obtain said catalyst component.