Modified phosphinimine catalysts for olefin polymerization

A process for producing a polyethylene copolymer having a density of from 0.910 g/cm3 to 0.927 g/cm3, a melt index (I2) of from 0.25 to 5.0 g/10 min, a melt flow ratio (I21/I2)<20, and a molecular weight distribution (Mw/Mn)≦3.0;

• the process comprising polymerizing ethylene and an alpha olefin in a gas phase reactor with a 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 1 to 30 when y is 1.