Patent ID: 7759445

Claim:
A process for preparing an olefin polymer by (co)polymerization of ethylene or ethylene with up to 10% by weight, based on the total amount of monomers, of a 1-olefin of formula R—CH═CH 2 , wherein R is an unbranched or branched alkyl radical comprising from 1 to 12 carbon atoms, in suspension, in solution, or in gas phase at a temperature from 20 to 120° C., and a pressure from 0.2 to 6.0 MPa in presence of a catalyst comprising a reaction product of a magnesium alkoxide with a tetravalent transition metal compound, wherein a magnesium alkoxide of formula I Mg(OR 1 )(OR 2 ) (I), wherein R 1 and R 2 are identical or different, and are each an unbranched or branched alkyl radical comprising from 1 to 20 carbon atoms, or a radical (CH 2 ) n OR 3 ; R 3 is an alkyl radical comprising from 1 to 4 carbon atoms; and n is an integer from 2 to 6; is suspended or dispersed as gel in an inert solvent, and is reacted with a tetravalent transition metal compound of formula II M 1 X m (OR 4 ) 4-m (II), wherein M 1 is titanium, zirconium or hafnium; R 4 is an alkyl radical comprising from 1 to 9 carbon atoms; X is a halogen atom; and m is an integer from zero to 4; at a temperature ranging from 20 to 140° C. in a molar ratio of Mg:M 1 of 1:0.05-10; the reaction product is then after-treated thermally at a temperature ranging from 90 to 200° C. for a period from 10 to 180 minutes, and wherein the catalyst provides in a single stage polymerization process producing a polymer comprising a medium to broad molar mass distribution, expressed as a M w /M n greater than 6.9.