Patent ID: 6997997
Filing Date: 2006-02-14
Classification: C06B,C08G

Abstract:
1. A method of preparing a thermoplastic elastomer, comprising: dissolving A blocks and B blocks terminated with respective isocyanate-reactive groups into a solution comprising at least one non-halogenated solvent selected from the group consisting of at least one organic ether, at least one organic ester, and at least one organic ketone, the A blocks being crystalline below about 75° C. and derived from monomers comprising at least one member selected from the group consisting of oxetane derivatives and tetrahydrofuran derivatives, the B blocks being amorphous above about −20° C. and derived from monomers comprising at least one member selected from the group consisting of oxetane and derivatives thereof, tetrahydrofuran and derivatives thereof, and oxirane and derivatives thereof; drying the dissolved A blocks and the dissolved B blocks of water by azeotropic distillation of the at least one non-halogenated solvent; end-capping the dried A blocks and the dried B blocks in the at least one non-halogenated solvent by reacting the dried A blocks and the dried B blocks with at least one diisocyanate in which a first isocyanate moiety thereof is substantially more reactive with the terminal groups of the A blocks and the B blocks than a second isocyanate moiety thereof, wherein the more reactive first isocyanate moiety is capable of reacting with the terminal groups of the A blocks and the B blocks, leaving the less reactive second isocyanate moiety free and unreacted; and linking the end-capped A blocks and the end-capped B blocks together in the at least one non-halogenated solvent with at least one linking compound comprising two isocyanate-reactive groups which are sufficiently sterically unhindered to react with the free and unreacted isocyanate moieties of the end-capped A blocks and the end-capped B blocks.