| 摘要 |
A catalyst component is in the form of a granular spherical solid with at least 80% of the granules between 30 and 40 microns in size, a surface area of 15 to 30 m2/g and a porosity of 40 to 80 volumes % and definable (in atomic proportions) by the formula: Ti1 Mg0,3-3,1 Al0,4-0,65 Cl3,2-8,2 (Et + OEt + OR')1,9-3 where Et denotes the ethyl group; OEt denotes the ethoxy group and OR' is an alkoxy group containing from 1 to 8 carbon atoms in the alkyl portion, and in which the ration of trivalent titanium to the sum of trivalent and tetravalent titanium is in the range from 0.8/1 to 1/1. The solid catalyst component is obtained by: a) Spray-drying a solution of magnesium chloride in ethanol to produce a solid substrate in the form of spherical granules containing alcoholic hydroxyl groups, and b) Suspending the solid substrate in an inert liquid and contacting and reacting the resulting suspension firstly with measured quantities of a titanium tetra-alkoxide and then with measured quantities of diethyl aluminium chloride or ethyl aluminium sesquichloride. The solid catalyst component is used in combination with trialkyl aluminium to polymerize ethylene or to copolymerize ethylene with an alpha-olefin, more particularly by the suspension technique. |
