Verfahren zur Herstellung von schaumfoermigen Athylencopolymerisaten

摘要

1,227,454. Expanded ethylene/ester copolymers. BADISCHE ANILIN- & SODAFABRIK A.G. 15 Aug., 1968 [16 Aug., 1967], No. 39077/68. Headings C3C and C3P. A cross-linked expanded polymer is produced by mixing, e.g. in an extruder, a thermoplastic copolymer of ethylene with a vinyl ester of a saturated acid or an ester-of an ethylenically unsaturated acid in the plastic condition with a polyisocyanate and an expanding agent under such pressure that the copolymer is not expanded followed by decompression to allow expansion. The ethylene copolymer may contain units derived from vinyl acetate or acrylic acid and n-hexyl, ethyl or n- or tert-butyl acrylate. The polyisocyanate may be 4,41- dicyclohexylmethane di-isocyanate or its 3,31- dimethyl derivative; others are also exemplified. The expanding agent may be a mixture of iso- and n-butane and/or dichlorodifluoromethane, propane or neopentane or azodicarbonamide or p,p1 - oxybenzene - sulphohydrazide. Talc may be used as a nucleating agent. The copolymer mixture may also contain polybutene, polyisobutylene or polypropylene and zinc oxide.