Patent ID: 6319998
Filing Date: 2001-11-20
Classification: C08F,C08L,Y10S

Abstract:
A method of making a copolymer blend by solution polymerization comprising:(a) feeding a first set of at least two different monomers and a solvent in controlled proportions to a first continuous flow stirred tank reactor;(b) adding a metallocene catalyst to the first reactor;(c) operating the first reactor to polymerize the first set of monomers to produce an effluent containing a first copolymer;(d) feeding the effluent of (c) to a second continuous flow stirred tank reactor;(e) feeding a second set of at least two different monomers in controlled proportions to the second reactor and optionally additional solvent; and(f) operating the second reactor to polymerize the second set of monomers to produce a second copolymer,wherein the monomers of the first and second set of monomers are selected from the group consisting of ethylene, higher alpha-olefins and non-conjugated dienes and wherein the monomer proportions in the first reactor and the second reactor are controlled so that the first copolymer has 0 to 85 wt % ethylene, the second copolymer has 0 to 85 wt % ethylene, and the copolymer blend has 6 to 85 wt % ethylene; andwherein 50-100 wt % of the total amount of catalyst added to all reactors is added to the first reactor.