US 10,870,923 B2 · Can pretreatment for improved coat adhesion

Abstract

The invention relates to use of an aqueous composition for pretreating can body stock, whereby an inorganic-organic conversion layer is formed, which effects outstanding sliding behavior of the shaped can body stock and in addition offers an outstanding holding primer for subsequent coating. The invention comprises a process in which can body stock which is deep-drawn to form a half-open can cylinder, before further shaping processes, is contacted with an acidic aqueous composition which contains water-soluble inorganic compounds of Zr, Ti, Si, Hf or Ce, water-soluble polymers having carboxyl groups or hydroxyl groups and also a dispersed wax. Both outer and inner surfaces of metallic can cylinders can be pretreated in the process. The invention also relates to an acidic aqueous composition for use in the pretreatment process, which contains water-soluble polymers selected from condensation products of glycoluril and aldehydes.

Claims14

Dependent claims

A process for surface-treating a can cylinder which is deep-drawn from a metal sheet and is open at one end, in which process:

1.) at least an outer circumferential surface of the can cylinder is contacted with an acidic aqueous composition which contains:
a) at least one water-soluble compound of elements Zr, Ti, Si, Hf, and/or Ce;
b) at least one water-soluble organic resin, which comprises at least carboxyl groups or hydroxyl groups, having an acid value and/or a hydroxyl value wherein a sum of the acid value and/or hydroxyl value of the at least one water-soluble organic resin is at least 50 mg KOH/g, wherein b) comprises condensation products of glycoluril with primary aldehydes, the condensation products having a degree of alkylation below 20%;
and
c) at least one dispersed wax;
and
2.) wherein at least the outer circumferential surface of the can cylinder that is open at one end is provided with a protective coating after being brought into contact with the acidic aqueous composition;
and, optionally, after a directly subsequent flushing step.

5 more elements

Dependencies are inferred from the claim text.

Can pretreatment for improved coat adhesion

Life of this patent

Can pretreatment for improved coat adhesion

Life of this patent

Abstract

Claims14