Process for producing multiblock copolymer and products produced thereby

Abstract

The process disclosed herein involves the continuous preparation of a multiblock copolymer of two monomers or more such as butadiene and styrene, butadiene and isoprene, etc. This process comprises the alternate feeding of first one monomer stream and then another monomer stream differing in monomer composition from the first monomer stream, each stream of monomer being interrupted while the other stream of monomer is being fed continually into the polymerization system containing an anionic polymerization catalyst capable of polymerizing each of said monomers. A product stream is withdrawn from the polymerization system at the same rate as the total of the feed streams, thereby effecting a continual flow through the polymerization system. The rate of catalyst feed is controlled to give the desired molecular weight to the multiblock copolymer; the size of each block in the copolymer is controlled by the time of flow of the respective monomer and the concentration of monomer in the monomer feed; and the number of blocks is controlled by the number of alternating feed steps that are performed during the residence time in the polymerization system.

Dependencies are inferred from the claim text.