| 摘要 |
The corrosion resistance of phosphatized metal surfaces is improved by treating them with an aqueous, alcoholic or aqueous/alcoholic solution of one or more of the following compounds: (1) polyvinyl phosphonic acid, (2) a copolymer of vinyl phosphonic acid, or (3) a copolymer of an acid derivative of vinyl phosphonic acid containing only one free hydroxyl group at the phosphorus atom, per monomer unit (preferably a semi ester of vinyl phosphonic acid). After this treatment the coating is dried. The copolymers of (2) and (3) can be formed with mono- or poly-unsaturated organic compounds such as acrylic acid methacrylic acid, esters amides or nitriles thereof, vinyl esters (e.g. vinyl acetate or vinyl propionate) maleic anhydride or crotonic acid or more than one of these. The polymer concentration is 0.008-2%, preferably 0.02-0.5% by weight, and the solution may contain a wetting agent. The solution may be applied by spraying, brushing or immersion and contact times may be from one second up to two minutes at 4-70 DEG C. (preferably 10-25 DEG C.), the drying being carried out at 80-180 DEG C. (preferably 120-150 DEG C.). The treatment of steel plates having a zinc phosphate coating is described.ALSO:The corrosion-resistance of phosphatized metal surfaces, e.g steel plates, is improved by treating them with an aqueous, alcoholic, or aqueous/alcoholic solution of one or more of the following compounds:- (1) polyvinyl phosphonic acid, (2) a copolymer of vinyl phosphonic acid, or (3) a copolymer of an acid derivative of vinyl phosphonic acid, containing only one free hydroxyl group, at the phosphorus atom, per monomer unit (preferably a semi-ester of vinyl phosphonic acid). After this treatment the coating is dried. The copolymers of (2) and (3) can be formed with mono- or poly-unsaturated organic compounds such as acrylic acid, methacrylic acid, esters, amides or nitriles thereof, vinyl esters (e.g. vinyl acetate or propionate), maleic anhydride or crotonic acid, or more than one of these. The polymer concentration is 0,008-2%, preferably 0,02-0,5% by weight, and the solution may contain a wetting agent. The solution may be applied by spraying, brushing or immersion and contact times may be from a second up to two minutes at 4-70 DEG C. (preferably 10-25 DEG C.) the drying being carried out at 80-180 DEG C. (preferably 120-150 DEG C.). |
