Patent ID: 6624278
Filing Date: 2003-09-23
Classification: C08G

Abstract:
A Continuous process for producing a thermally stable thermoplastic polyurethane elastomer, comprising:A) obtaining a reaction mixture that includes as reactants (i) at least one substantially linear hydroxyl-terminated polyols having a number average molecular weight of 600 to 5000, and (ii) an amount of at least one organic diisocyanate, and (iii) a chain lengthening agent in the form of a did having a molecular weight of 62 to 500, optionally along with at least one trial, wherein NCO to OH ratio of all reactants including acid H compounds is in the range of 0.9:1 to 1.2:1, said amount of diisocyanate established to result in the maximum melt viscosity of the reaction product prepared from (i), (ii) and (iii), andB) adding to said reaction mixture at least one acid H compound in an amount of 0.3 to 6 mol. %, relative to the amount of the chain-lengthening agent, sufficient to result in an elastomer having a constant melt viscosity that is at most 90% of said maximum.