PURPOSE: To obtain the titled elastomer excellent in heat drawability, by reacting a specified chain extender with a prepolymer obtained by adding a suitable amount of a low-MW glycol to a high-MW glycol and reacting the mixture with an organic diisocyanate at a specified ratio.
CONSTITUTION: 5W40mol% low-MW diol of formula I (wherein R is a 2W10C aliphatic or/and cycloaliphatic bivalent organic group) is added previously to a high-MW diol, number-average MW 1,500W4,000, m.p. ≤60°C. This diol mixture is reacted with 130W180mol%, pref., 140W165mol%, based on the mixture, organic diisocyanate to obtain an isocyanate group-terminated intermediate. The titled elastomer is obtained by dissolving the above intermediate in an inert polar organic solvent and chain-extending the intermediate with a diamine mixture containing ethylenediamine and 1W30mol%, based on ethylenediamine, 1,2- propylenediamine.
HIDACHI TOSHITAKA
SHINOHARA TSUKASA
MIKI MISAO
