| 摘要 |
The invention relates to the use of an acidic aqueous composition for pretreating cans, wherein an inorganic-organic conversion layer is formed in the course of the pretreatment, said conversion layer, as such, offering an excellent adhesive base for the wax which improves the sliding behavior of the formed can sheet metal and for the subsequent coating. The invention contains a wet-chemical pretreatment method in which a can cylinder is first brought into contact with an acidic aqueous composition that contains water-soluble inorganic compounds of the elements Zr, Ti, Si, Hf or Ce and water-soluble polymers comprising carboxyl groups or hydroxyl groups and subsequently with an aqueous dispersion of a wax. In this manner, the sliding and shaping properties required for the other method steps of the can production process are imparted to the can cylinders and an excellent adhesive base for a coating is additionally provided. The invention further relates to an acidic aqueous composition which is particularly suitable for the pretreatment method and which contains water-soluble polymers selected from the condensation products of glycoluril and aldehydes. The invention further relates to a method for producing can cylinders, said method including the pretreatment according to the invention. |
