Abstract:
Solid Lewis adducts comprising MgCl2, a Lewis base (LB) belonging to ethers, esters, ketones, silanes or amines and an alcohol ROH, in which R is a C 1-C 15 hydrocarbon group optionally substituted with heteroatoms containing groups, which compounds are in molar ratios to each other defined by the following formula MgC12(ROH) m(LB)n in which m ranges from 0.05 to 6, n ranges from 0.08 to 6. These adducts allow to prepare catalysts having a good morphological stability and high polymerization activities.
Abstract:
The present invention relates to catalysts component for the polymerization of ethylene and its mixtures with olefins CH2=CHR, wherein R is an alkyl, cycloalkyl or aryl radical having 1-12 carbon atoms, comprising Ti, Mg, halogen, and 1,2- dimethoxyethane as internal electron donor compound. The catalyst of the invention is suitably used in (co)polymerization processes of ethylene to prepare (co)polymers having narrow Molecular Weight Distribution (MWD) and high bulk density.
Abstract:
The present invention relates to a slurry process for preparing an ethylene polymer having a melt flow ratio F/P, which is the ratio among the melt index value measured according to ASTM 1238 condition "F" and the melt index value measured according to ASTM 1238 condition "P" of equal to or lower than 27, carried out in two or more stages of polymerization at temperatures in the range from 60 to 120°C, in which at least two of the said two or more polymerization stages are carried out under different amounts of molecular weight regulator, said process being carried out in the presence of (A) a solid catalyst component comprising Ti, Mg, halogen, having a porosity (P F ), measured by the mercury method and due to pores with radius equal to, or lower than, 1µm, of at least 0.3 cm 3 /g and a surface area determined by BET method, of lower than 100 m 2 /g, and being further characterized by the fact that more than 50% of the titanium atoms are in a valence state lower than 4 and (B) of an organoaluminum compound.