| 摘要 |
<p>1534299 Cross-linking polymers via grafted silane groups BICC Ltd 24 Sept 1976 [26 Sept 1975] 39606/75 Addition to 1526398 Heading C3P [Also in Division B5] Cross-linked extruded products are obtained by: (1) metering into a first 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 said first extruder to form a homogeneous mixture; (3) feeding the mixture directly without exposure to the atmosphere to a second screw extrusion machine; (4) raising the temperature of the mixture sufficiently to effect grafting of silane groups to the polymer; (5) extruding the mixture through an extrusion die to form an elongate shaped product; and (6) cross-linking the grafted polymer by the action of moisture. The process is illustrated with reference to the production of electric cable coverings, suitable materials being polyethylene, vinyl trimethoxysilane, dicumyl peroxide and dibtuyl tin dilaurate.</p> |
