PRODUCTION OF BLEND OF POLYOLEFIN AND ORGANOPOLYSILOXANE

A process for the production of a polymer composition is disclosed. The polymer composition comprises an organopolysiloxane dispersed in a thermoplastic organic polymer liable to thermo-radical degradation or cross-linking when subjected to a high compounding energy at a temperature above its melting point. In a first step (I), a thermoplastic organic polymer and an organopolysiloxane are mixed at a temperature at which both the thermoplastic organic polymer and the organopolysiloxane are in liquid phases to form a masterbatch. In a second step (II), the masterbatch is mixed with further thermoplastic organic polymer to form a polymer composition having a lower concentration of organopolysiloxane than that in the masterbatch. In the first step (I), the thermoplastic organic polymer and the organopolysiloxane are mixed in the presence of an additive capable of inhibiting the thermo-radical degradation or cross-linking of the thermoplastic organic polymer. The organopolysiloxane of the masterbatch remains stable during processing.