Partially cross-linkable compositions and process for preparing partially cross-linked thermoplastic elastomers

摘要

A composition essentially consisting of a monoolefin copolymer rubber such as an ethylene-propylene copolymer rubber and a polyolefin resin such as polypropylene is granulated and then suspended, by stirring, in water containing a suspending agent. Then, a cross-linking agent is dispersed in the resulting suspension and introduced into the granules at a temperature lower than the decomposition temperature of the cross-linking agent to obtain a granular composition uniformly impregnated with the cross-linking agent. This composition is used as such or as a masterbatch to prepare partially cross-linked thermoplastic elastomers. Such compositions having a cross-linking agent content of not greater than 5% by weight based on the amount of the rubber component can be converted into partially cross-linked thermoplastic elastomers having a uniform degree of cross-linking, simply by heating the impregnated granules statically to effect the cross-linking reaction.