Patent ID: 6034026
Filing Date: 2000-03-07
Classification: C08F

Abstract:
A process for the polymerization of ethylene by the use of a procatalyst comprising a particulate inorganic support, a chlorine compound deposited on said support, a magnesium compound deposited on said support and a titanium compound deposited on said support, wherein the chlorine compound is optional when the magnesium compound and/or the titanium compound contain chlorine, which procatalyst has an activity balance AB that is greater than 3.2, wherein the polymerization activity of said procatalyst is expressed as kg PE/g cat.h and is represented by the formula:AB=((A+A'):2.multidot.log (MFR.sub.2 ':MFR.sub.2):(A-A'))whereinMFR.sub.2 is the melt flow rate of polyethylene produced by said procatalyst expressed in g/min units at a load of 2.16 kg, according to the standard ISO 1133, the absence of the upper index ' means a melt flow rate polymerization less than the melt flow rate polymerization indicated by the presence of the upper index ', and has been prepared by:(a) contacting the inorganic support with an alkyl metal chloride which is soluble in non-polar hydrocarbon solvents, and has the formula(R.sub.n MeCl.sub.3-n).sub.m ( 1)wherein R is a C.sub.1 -C.sub.20 alkyl group, Me is a metal of group III (13) of the periodic table, n=1 or 2 and m=1 or 2, or a combination of such compounds to give a first reaction product,(b) contacting said first reaction product with a compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium which is a contact product between a dialkyl magnesium and an alcohol, the dialkyl magnesium and the alcohol having been contacted at a molar ratio between 1:1.78 and 1:1.99, and is soluble in non-polar hydrocarbon solvents, to give a second reaction product, and(c) contacting said second reaction product with a titanium compound which contains chlorine, having the formulaCl.sub.x Ti(OR.sup.IV).sub.4-x ( 2)wherein R.sup.IV is a C.sub.2 -C.sub.20 hydrocarbyl group and x is 3 or 4, to give said procatalyst.