Block copolymers of alkadienes and monovinyl arenes
AssigneePhillips Petroleum Company
InventorGeorge A. Moczygemba
Life of this patent
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Abstract
A copolymer having the formula A--B--C is disclosed, which becomes a thermoplastic elastomer after essentially all the olefinic unsaturation therein has been removed by hydrogenation. A is a low vinyl poly-1,3-butadiene block, C is a poly(monovinyl arene) block, and B is either a block of acyclic, conjugated alkadiene containing 5-12 carbon atoms or a random copolymer block of at least one acyclic, conjugated alkadiene containing 4-12 carbon atoms, and at least one monovinyl arene containing 8-16 carbon atoms. The hydrogenated copolymer has the structure D--E--C in which D is essentially completely hydrogenated A, and E is block B from which the olefinic unsaturation is essentially removed by hydrogenation.
Claims9
A copolymer having the structure D-E-C, wherein
- D is a hydrogenated block of low vinyl poly-1,3-butadiene,
- E is a hydrogenated polyisoprene block, and
- C is a polystyrene block.
A process for producing a copolymer comprising
- a. introducing 1,3-butadiene into a reactor and polymerizing the 1.3-butadiene in the presence of a polymerization catalyst and under polymerization conditions and essentially in the absence of vinyl promoting agents until essentially all the 1,3-butadiene has polymerized,
- b. adding isoprene to the reaction product of the first polymerization step,
- and polymerizing essentially all the monomers introduced in step b under polymerization conditions,
- c. adding styrene to the reactor and polymerizing this styrene under polymerizing conditions until essentially all of this monomer has polymerized,
- with the further provision that the process steps are either carried out in the sequence a--b--c or in the sequence c--b--a,
- d. hydrogenating essentially all the olefinic unsaturation of the polymer produced leaving the aromatic unsaturation essentially unchanged, and
- e. recovering the polymer as the product of the process.
Dependencies are inferred from the claim text.