Laminat af metalplader med svingningsdæmpende, selvhæftende mellemlag indeholdende en vinylacetat- og ethylenholdig copolymer

1,254,116. Vibration damping laminated systems. FARBWERKE HOECHST A.G. 3 Dec., 1968 [5 Dec.; 1967], No. 57349/68. Heading B5N. [Also in Divisions B2 and C3] A vibration damping laminated system comprises two plates, e.g. of metal such as steel, bonded together with an interlayer comprising a graft polymer of 55-90% by weight of styrene or a mixture of styrene and 0À1-10% by weight, based on the weight of the styrene, of a copolymerizable carboxylic acid, e.g. acrylic and/or methacrylic acid, on 45-10% by weight of a copolymer of 30-50% by weight of vinyl acetate and 50-70% by weight of ethylene. If the graft polymer contains a copolymerizable carboxylic acid it may be cross-linked with a compound containing a plurality of epoxide or isocyanate groups. The graft polymer may contain minor amounts of fillers, e.g. heavy spar, silicic acid, graphite, soot or a mixture thereof, and one or more plasticizers. The total thickness of the laminated system may be 1-6 mm. the thickness of the interlayer being 0À1-1 mm. and the ratio of the thicknesses of the plates being from 1:1 to 4:1. The graft polymer may be applied to the plates by trowelling, brushing or pouring at elevated temperature and the system cooled under pressure between rollers. A solution of the copolymer in styrene or styrene and acrylic and/or methacrylic acid mixture containing a polymerization initiator, e.g. tertiary butyl hydroperoxide, may be applied between the plates and the laminated system subjected to heating at 60-180‹ C. to effect grafting.