Method for making polymer blends by using series reactors

A method of making a copolymer blend by homogeneous solution phase polymerization, the method comprising:

• (a) copolymerizing a first set of monomers comprising ethylene and a C3 to C8 alpha-olefin in a first continuous flow stirred tank reactor, in the presence of a metallocene catalyst, to form an effluent comprising a first copolymer;
• (b) directing the effluent to a second continuous flow stirred tank reactor in series with the first reactor;
• and
• (c) copolymerizing a second set of monomers comprising ethylene and a C3 to C8 alpha-olefin in the second reactor, in the presence of a metallocene catalyst and the effluent from the first reactor, to form a blend of a second copolymer and the first copolymer, the polymer blend comprising from 6 to 85 wt % ethylene.

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, wherein the metallocene catalyst comprises two cyclopentadienyl ring systems locked into a rigid configuration through a bridging group;
• (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 85wt% ethylene, the second copolymer has 0 to 85wt% ethylene, and the copolymer blend has 6 to 85wt% ethylene;
• and
• wherein 50-100wt% of the total amount of catalyst added to all reactors is added to the first reactor.

A method of making a copolymer blend by homogeneous solution phase polymerization, the method comprising:

• (a) copolymerizing a first set of monomers comprising ethylene and a C3 to C8 alpha-olefin in a first continuous flow stirred tank reactor, in the presence of a metallocene catalyst comprising two cyclopentadienyl ring systems locked into a rigid configuration through a bridging group, to form an effluent comprising a first copolymer;
• (b) directing the effluent to a second continuous flow stirred tank reactor in series with the first reactor;
• and
• (c) copolymerizing a second set of monomers comprising ethylene and a C3 to C8 alpha-olefin in the second reactor, in the presence of a metallocene catalyst comprising two cyclopentadienyl ring systems locked into a rigid configuration through a bridging group and the effluent from the first reactor, to form a blend of a second copolymer and the first copolymer, the polymer blend comprising from 6 to 85wt% ethylene.