GB871296A - Adhesives and composite materials produced therewith - Google Patents

Abstract

An adhesive composition comprises a synthetic elastomer such as a butadiene/acrylonitrile copolymer with a Defs value lower than 2000 or butadiene/styrene, a thermosetting formaldehyde condensate which is soluble in organic solvents, one or more chromates, and an organic solvent for the synthetic elastomer and the formaldehyde condensate. The adhesive composition gives high bonding strengths when producing composite materials with polyvinyl chloride layers and other high molecular weight organic compounds. According to Examples, (1) a sheet, tube, or rod of iron, aluminium, copper or brass was cleaned with benzine, was sand-blasted and then dipped in to a solution having the following composition: 1000 ml. methyl ethyl ketone, 150g. copolymer of butadiene and acrylonitrile of Defs value about 500; 150g. thermosetting condensation product of phenol and formaldehyde, 20-45g. zinc chromate, 10-25g. potassium bichromate and 15-60g. zinc oxide. The coated material was dried for 10 minutes at 130 DEG -180 DEG C. and then dipped while hot or after cooling to room temperature, into a plasticized, pigmented polyvinyl chloride paste. After draining, curing was effected for 15 minutes at 180 DEG C. Bonds were also produced employing, in place of metals, polyamides, polyesters, glass, and glass fabrics. In other examples, the polyvinyl chloride paste had the following compositions: (4) 55 parts of polyvinyl chloride powder, 45 parts of a gelling or plasticizing mixture containing a relatively low volatile plasticizer, such as dioctyl phthalate or mepasin-sulphonic acid phenyl ethyl ester, a relatively highly volatile plasticizer or gelling agent, such as phthalic acid dimethyl ester, adipic acid dimethyl ester, glyceryl triacetate, diethyl adipate, benzoic acid dimethyl ester or mixtures thereof, stabilizers and pigments; (5) 100g. polyvinyl chloride, 150g. phthalic acid dimethyl ester (or the diethyl ester), 7g. kaolin, 1,5g. brown iron oxide, 0,7g. yellow iron oxide and 0,1g. carbon black.ALSO:An adhesive composition comprising a synthetic elastomer, such as butadiene/acrylonitrile or butadiene/styrene, a thermosetting formaldehyde condensate which is soluble in organic solvents, one or more chromates and an organic solvent for the elastomer and the condensate, is employed to bond polyinyl chloride, polyamide, synthetic or natural rubber, polyurethanes, polystyrene, polyacrylates and polycarbonates, including foamed polymers, to surfaces of synthetic resin, glass and metals such as iron, galvanised iron, aluminium, copper and brass. The bonding agent may be applied by spraying, dipping, brushing or with a roller. In Example (1) metal sheets, rods and tubes are cleaned with benzine, sandblasted and dipped into a methyl ethyl ketone solution containing a copolymer of butadiene and acrylonitrile, a thermosetting condensation product of phenol and formaldehyde, zinc chromate, potassium bichromate and zinc oxide, dried by heat, dipped while still hot into a plasticized polyvinyl chloride paste, drained and cured by heat. More than one coating of polyvinyl chloride may be applied. In Example 4 a metal tube is similarly coated, but the polyvinyl chloride paste contains both relatively low and relatively high volatile plasticizers. In Example 5 a diluted adhesive composition as in Example 1 is applied to metal plates by spraying, the plates are dried by heat and while still hot are sprayed with a pigmented polyvinyl chloride composition containing phthalic acid dimethyl or diethyl ester, and dried by heat. In Example 6 the inner wall of a metal vessel is coated with the diluted adhesive of Example 5 and heated, and a foam material containing urethane groups produced in the vessel, e.g. by reaction of polyisocyanates with polyesters containing hydroxyl or carboxyl groups.