Patent ID: 8809473

Claim:
A method for altering the composition distribution of an ethylene copolymer, the method comprising: introducing a polymerization catalyst into a gas phase reactor, the polymerization catalyst comprising a phosphinimine catalyst, an inert support, and a cocatalyst; feeding a catalyst modifier into the reactor, the catalyst modifier comprising a compound having the formula: R 1 R 2 x N((CH 2 ) n OH) y where R 1 is a hydrocarbyl group having from 5 to 30 carbon atoms, R 2 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 1 to 30 when y is 1; and polymerizing ethylene and an alpha-olefin in the reactor to give the ethylene copolymer; wherein the composition distribution of the ethylene copolymer is altered by changing the amount of the catalyst modifier fed to the reactor by at least 5 ppm from a first amount of catalyst modifier to a second different amount of catalyst modifier, wherein the amount of catalyst modifier fed to the reactor is from 0 to 100 ppm (based on the weight of copolymer produced); wherein the phosphinimine catalyst has the formula: (1,2-(R*)(Ar—F)Cp)Ti(N═P(t-Bu) 3 ) X 2 , where R* is a straight chain alkyl group, Ar—F is a perfluorinated aryl 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.