Modified phosphinimine catalysts for olefin polymerization

A polymerization process comprising contacting ethylene and at least one alpha olefin with a polymerization catalyst in a gas phase reactor, the polymerization catalyst comprising:

• i) a phosphinimine catalyst, ii) an inert support, iii) a cocatalyst, and iv) a catalyst modifier;
• wherein the catalyst modifier is present in from 0.25 to 6.0 weight percent based on the weight of i), ii), and iii) of the polymerization catalyst and comprises a compound having the formula:
• R1R2xN((CH2)nOH)y where R1 is a hydrocarbyl group having from 5 to 30 carbon atoms, R2 is hydrogen or a hydrocarbyl group having from 1 to 30 carbon atoms, x is 1 or 0, y is 1 when x is 1, y is 2 when x is 0, each n is independently an integer from 1 to 30 when y is 2, and n is an integer from 1to 30 when y is 1;
• and wherein the polymerization catalyst is prepared by adding all of the catalyst modifier to the inert support prior to the addition of the phosphinimine catalyst and prior to the addition of the cocatalyst;
• wherein the phosphinimine catalyst has the formula:
• (1,2-(R*)(Ar—F)Cp)Ti(N═P(t-Bu)3)X2, where R* is a straight chain alkyl group, Ar—F is a perfluorinated phenyl group, a 2,6 fluoro substituted phenyl group, a 2,4,6 fluoro substituted phenyl group, or a 2,3,5,6 fluoro substituted phenyl group, and X is an activatable ligand.