Patent ID: 7812103

Claim:
A method for reducing the formation of agglomerates during the transition between two different grades of polyolefin copolymer products being made during the polymerization thereof, which method includes the steps of: copolymerizing two or more polyolefins in a fluidized bed gas phase reactor in the presence of a suitable catalyst and under a polymerization temperature T A that forms a polyolefin copolymer A having a density d A , a melt index MI A and a sintering temperature T SA ; and transitioning polyolefin copolymer A to a polyolefin copolymer B having a density d B , a melt index MI B and a sintering temperature T SB , where d B >d A and MI B ≦MI A , via a transition polyolefin copolymer AB having a density d AB and a melt index MI AB , by increasing the polymerization temperature in the reactor to a temperature T x1 which is equal to or higher than 0.5×(T A +T SB ) and lower than the sintering temperature T SB of the polyolefin copolymer B minus 2° C. until polyolefin copolymer B is continuously being produced without or with a substantially reduced amount of agglomerate formation.