Abstract:
A process for cross-linking an elastomer-containing thermoplastic polyolefin composition comprising the steps of preparing a masterbatch by mixing and/or masticating an elastomeric polyolefin with a cross-linking co-agent, and optionally an additive, in the presence of a thermoplastic polyolefin; then, cooling the masterbatch obtained in the preceding step at least up to the solidification of the thermoplastic polyolefin; and finally mixing and/or masticating the masterbatch, after the cooling step, with a cross-linking agent and optionally an additive.
Abstract:
A polyolefin composition, particularly suited for preparing gaskets for closures, comprising: A) from 60 to 89% by weight of a copolymer of butene-1 with ethylene having a copolymerized ethylene content of up to 18% by mole and no melting peak detectable at the DSC at the second heating scan; B) from 11 to 40% by weight of an ethylene polymer having density of from 0.900 to 0.970 g/cm3, measured according to ISO 1183 at 23°C; wherein the amounts of A) and B) are referred to the total weight of A) + B).