METHOD OF PRODUCING THERMOPLASTIC ELASTOMERS HAVING ALTERNATE CRYSTALLINE STRUCTURE SUCH AS POLYOXETANE ABA OR STAR BLOCK COPOLYMERS BY A BLOCK LINKING PROCESS

Abstract

A method of preparing a thermoplastic elastomer having A blocks and at least one B block, wherein said A blocks are crystalline at temperatures below about 60 DEG C. and said B block is amorphous at temperatures above about -20 DEG C., said A blocks each being polyethers derived from monomers of oxetane and its derivatives and/or tetrahydrofuran and its derivatives, the method comprising: providing monofunctional hydroxyl terminated A blocks which are crystalline at temperatures below about 60 DEG C. and separately providing di-, tri- or tetrafunctional hydroxyl terminated B blocks which are amorphous at temperatures above about -20 DEG C., end-capping said A blocks by separately reacting said A blocks with a difunctional diisocyanate in which one isocyanate moiety is at least about five times as reactive with the terminal hydroxyl group of the A blocks as the other isocyanate moiety, whereby the more reactive isocyanate moiety tends to react with the terminal hydroxyl group of the A blocks, leaving the less reactive isocyanate moiety free and unreacted, and adding di-, tri- or tetrafunctional B block to the end-capped A blocks at approximately the stoichiometric ratios that they are intended to be present in the thermoplastic elastomer such that the free and unreacted isocyanate moiety on the end-capped A block reacts with a functional moiety of the B block to produce ABA or AnB thermoplastic elastomers.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1ROBERT B. WARDLE