| 摘要 |
1,050,164. Foamed ethylene polymers. DYNAMIT NOBEL A.G. Aug. 28, 1964 [Aug. 30, 1963], No. 35439/64. Headings C3C and C3P. A process for the continuous production of a foamed cross-linked ethylene polymer and/or copolymer which has incorporated therein a blowing agent and a cross-linking agent comprises softening the ethylene polymer and/or copolymer with an organic solvent having a boiling-point of at least 40‹ C. to permit the incorporation of the blowing and cross-linking agents into the polymer prior to extrusion and then extruding the composition at a temperature of from 100-180‹ C. The organic solvent may be absorbed in a filler before being incorporated in the polymer. Solvents specified are halogenated hydrocarbons, benzine, benzene, toluene, xylene, cyclohexane, methyl ethyl ketone, acetone, methyl glycol acetate, butyl acetate and butanol. Cross-linking agents are advantageously dialkyl peroxides with tertiary carbon atoms. Ethylene polymers and copolymers used in examples are high pressure polyethylene, low pressure polyethylene and a copolymer of 67% ethylene and 33% vinyl acetate. Blowing agents may be either solid or liquid, those used in the examples are dinitrosopentamethylene tetramine, azodicarbonamide, trichloroethylene, methylene chloride, 1,2-dichlorotetrafluoroethane and trichloromonofluoromethane. |
