Patent ID: 7834117

Claim:
A process for preparing crystalline ethylene (co)polymers comprising polymerizing ethylene alone or with olefins CH 2 ═CHR, wherein R is hydrogen or a C 1 -C 12 hydrocarbyl, in presence of a catalyst system comprising: (a) a solid catalyst component obtained by reacting a titanium compound comprising at least one Ti—Cl bond with a catalyst precursor comprising formula MgCl n (OR I ) 2-n , wherein n is from 0.5 to 1.5, the solid catalyst component comprising Ti, Mg, halogen, and OR I , wherein R I is a C 1 -C 12 hydrocarbon optionally comprising at least one heteroatom, wherein the solid catalyst component comprises a OR I /Ti molar ratio of at least 0.5, and an amount of titanium higher than 4% by weight, with respect to a total weight of the solid catalyst component, the solid catalyst component comprising a SS—NMR pattern comprising at least one signal (A) comprising a maximum in region 60-75 (ppm), and at least one signal (B) comprising a maximum in region 78-108 (ppm), wherein a ratio I A /I B is higher than 0.8, and wherein I A is an integral of the at least one signal comprising a maximum in the region between 60 and 75 ppm; and I B is an integral of the at least one signal comprising a maximum in the region between 78 and 108 ppm; and (b) an aluminum alkyl compound as a cocatalyst.