Curable adhesive
AssigneeTh. Goldschmidt AG
InventorsJurgen Fock, Dietmar Schedlitzki
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Abstract
The invention relates to a curable adhesive based on a reactive acrylate and/or methacrylate copolymer. The reaction principle, on which the curing of the adhesive is based, is the reaction of the hydroxyl groups of the .omega.-hydroxyalkyl esters of acrylic and/or methacrylic acids with the isocyanate groups of the polyisocyanates or their partial reaction products with polyols. The inventive adhesives can be used without solvents or with only a slight content of organic solvents. They adhere well to plastic and metal surfaces, even when exposed to the effects of water or water vapor. The best values for the drum peel strength are obtained from acrylic copolymers whose molecular weight falls in the range of 1,000 to 3,000.
Claims8
A curable adhesive comprising as the active components:
- (a) a copolymer obtained by the polymerization of:
- (a.sub.1) 25 to 64.8 weight percent of one or more alkyl esters of acrylic or methacrylic acid having 1 to 8 carbon atoms in the alkyl radical,
- (a.sub.2) 20 to 40 weight percent of acrylonitrile, methacrylonitrile or vinyl acetate,
- (a.sub.3) 15 to 35 weight percent of one or more .omega.-hydroxyalkyl esters of acrylic or methacrylic acid having 1 to 5 carbon atoms in the alkyl radical,
- (a.sub.4) 0.2 to 5 weight percent of glycidyl acrylate or glycidyl methacrylate, and
- (a.sub.5) 0 to 35 weight percent of monomers selected from the group consisting of vinyl propionate, styrene, acrylamide, and methacrylamide in the presence of mercapto group-containing controllers, which have at least one hydroxyl group in the molecule, the sum of the monomers (a.sub.1) to (a.sub.4) adding up to 100 weight percent and the copolymer having an average molecular weight of 800 to 2,500, and
- (b) one or more polyisocyanates or their partial reaction products with polyols, in which the molecule possesses on the average, at least 2 isocyanate groups,
- the components (a) and (b) being present in such a ratio that 1 to 1.3 isocyanate groups of component (b) correspond to one hydroxyl group of component (a).
Dependencies are inferred from the claim text.