| 摘要 |
1526398 Cross-linking polymers via grafted silane groups BICC Ltd and ETABS MAILLEFER SA 5 Dec 1975 [6 Dec 1974] 52917/74 Heading C3P [Also in Division B5] Cross-linked extruded products are obtained by (1) metering into a screw extrusion machine a polymer, a hydrolysable unsaturated silane, a free-radical generator and a silanol condensation catalyst; (2) blending said materials in the barrel of the extruder and then raising the temperature sufficiently to effect grafting of the silane to the polymer; (3) extruding the reaction mixture through an extrusion die to form an elongate shaped product; and (4) cross-linking the grafted polymer by the action of moisture. The extrusion machine may be of the type having in succession a premixing zone, a homogenizing zone and a metering zone, the homogenizing zone being one in which material to be extruded is forced over the flight of the extruder screw from a converging groove to another groove not otherwise communicating with the converging groove. Examples relate to the production of pipes and cable coverings from polyethylene, vinyl trimethoxy silane, a peroxide, dibutyl tin dilaurate or dimaleate (or a commercially identified catalyst), an antioxidant, and, in most cases, carbon black. |
