摘要 |
An elastomer which is the reaction product of : (a) at least one organic polyisocyanate; (b) at least one compound containing a plurality of isocyanate-reactive groups and having a molecular weight greater than 600, and (c) at least one chain extender having a molecular weight not exceeding 600, wherein at least one of components (a) and (b) is or includes a compound having a molecular weight greater than 600 and at least two reactive sites, at least one of which sites contains at least two isocyanate or isocyanate-reactive groups which are separated one from another by a chain of from 2 to 30 atoms and from the reactive groups in other reactive sites by a chain of more than 30 atoms. |