DYNAMIC VULCANIZATION OF POLYMER BLENDS IN SERIAL REACTORS.

摘要

A process for dynamically vulcanizing a polymer mixture polymerized in solution, to provide a thermoplastic elastomeric product, comprising the steps of: a) feeding a first set of monomers and a solvent, in predetermined proportions, to a first stirred tank reactor of continuous flow, b) add a metallocene catalyst to the first reactor, c) operate the first reactor to polymerize the first set of monomers, to produce an effluent containing a first polymer, d) feed the effluent from (c) to a second continuous flow stirred tank reactor, e) feeding a second set of monomers, in predetermined proportions, to the second reactor, and optionally additional solvent, f) operating the second reactor to polymerize the second set of monomers, to produce a second polymer, g) mix the resulting first and second polymers, under heat and shear conditions or so that the mixture flows, and h) adding a curing agent to one of the polymers to at least partially cross-link said polymer by dynamic vulcanization, under shear conditions at a temperature at which the mixture flows, in which the first and second set of monomers is chosen from a group consisting of ethylene, higher alpha-olefin and an unconjugated diene, and in which the proportions of the monomers in the first and second reactors are controlled so that the first polymer has 0 to 85% by weight of ethylene, the second polymer has 0 to 85% by weight of ethylene, and the polymer mixture has 6 to 85% by weight of ethylene, and in which an amount greater than 50 is added to the first reactor % by weight of the total amount of catalyst added to all reactors, and in which the proportions of monomers in the first reactor and in the second reactor are controlled so that the ethylene content of the first and second polymers differs re so that (a) the first polymer is semi-crystalline and the second polymer is amorphous, or (b) the first polymer is amorphous and the second polymer is semi-crystalline.