Multistage pretreatment of tinplate prior to coating thereof with lacquer

• Main Authors: ROTH MARCEL, STODT JUERGEN, WOLPERS MICHAEL, SUNDERMEIER UTA
• Format: Patent
• Language: Chinese; English
• Published: 04.12.2013
• Subjects: ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; APPARATUS THEREFOR; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS,e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES,DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; CONVEYING; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; HANDLING THIN OR FILAMENTARY MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; PACKAGES; PACKAGING ELEMENTS; PACKING; PERFORMING OPERATIONS; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; STORING; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING

The invention relates to a two-stage method for the anti-corrosive pretreatment of tinplate, in which an anti-corrosive primer coating is already applied in a first step, said primer coating effectively preventing the shiny metal surface of the pretreated tinplate from turning black when the pretreated tinplate of the invention that is provided with a coating lacquer is in contact with liquids containing or releasing sulfur compounds and with food containing protein. In the disclosed method, the tinplate is anodically polarized in an electrolyte containing at least one inert water-soluble salt and is then brought in contact with an acidic aqueous composition containing water-soluble inorganic compounds of the elements Zr, Ti, Hf, and/or Si. Tinplate pretreated according to the invention can be used in particular for the production of food-safe packaging such as beverage cans or tin cans.