METHOD OF PREPARING LOW-DENSITY ETHYLENE COPOLYMERS

Method for the copolymerization of ethylene with C4-CB alpha-olefins by means of a suspension method in an organic liquid, at a temperature of from 50° C to 70° C, at a pressure of less than about 10 bar, on a Ziegler catalyst constituted by: a) an alkylaluminium or alkylaluminium halide; b) the product of the reaction of a halogenated derivative oftitanium with a support material; the support material being the solid, spheroidal product of the spray drying of a solution of magnesium chloride in ethanol containing at least one additional compound chosen from the following classes:- aliphatic, cycloaliphatic or aromatic liquid hydrocarbons with a boiling point higher than that of ethanol at atmospheric pressure;- polar, organic hydroxy or ester compounds which are solid or liquid with a boiling point higher than that of ethanol at atmospheric pressure;the solid, spheroidal, spray-dried product also having the following characteristics:- particle form: spherical with a size of from 1 to 100 microns.- Apparent density of the particles: from 0.1 to 1 g/ml;- alcoholic hydroxyl group content: from 1.5 to 20% by weight;- surface area: from 10 to 100 m2/g;- porosity from 1.2 to 3.5 ml/g;- pore radius: from 1,000 to 65,000 Angstroms.