| abstract |
A process for the preparation of a segmented thermoplastic elastomer, by conversion in a melt system ofn a. one or more-OH and/or-COOH groups- containing bifunctional polyesters or polyester amides having a melting point not higher than 100°C and a molecular weight in the range of 500 to 5000, and, b. one or more-OH and/or-COOH groups- containing bifunctional polyesters or polyester amides having a melting point not lower than 180°C and a molecular weight in the range of 500 to 5000 in the presence of such an amount of diisocyanate that the ratio between the number of -NCO groups and functional groups of both the low-melting and the high-melting compounds is at least 1,0 and at most 1,5, the transesterificafion catalyst present in one segment or in both being deactivated prior to the conversion process. n The polymers resulting from the process may be heated for several hours at a temperature of 240°C without losing their elastomeric properties. |