CONTROLLING THE PLACEMENT OF COMONOMER IN AN ETHYLENE COPOLYMER

摘要

A process for controlling the placement of alpha olefins within an ethylene copolymer. The process involves polymerizing ethylene and an alpha olefin in the gas phase while changing the breadth of control over the molar ratio of ethylene to comonomer and/or hydrogen which is being fed to a polymerization reactor. At tighter control breadths, the alpha olefin may be incorporated mainly in the higher molecular weight portions of the ethylene copolymer. At looser control breadths, the alpha olefin may be incorporated more evenly throughout the ethylene copolymer or mainly in the lower molecular weight portions of the ethylene copolymer

主权项

1. A method of controlling the placement of comonomer in an ethylene copolymer, the method comprising polymerizing ethylene (C2) and one or more comonomer (Cx) at an average Cx/C2 molar ratio with a single site catalyst system in a gas phase reactor and deliberately changing the variability of the Cx/C2 molar ratio within the gas phase reactor wherein the variability is measured as the percent standard deviation in the Cx/C2 molar ratio from the average Cx/C2 molar ratio.