METHOD FOR MANUFACTURING COATED CAN LIDS

摘要

The present invention relates to a method for manufacturing coated can lids from aluminum strip, and is based on the finding that flexible, easily formable coatings having high abrasion resistance result from the use of water-based lacquers containing a copolymer or a copolymer mixture of at least one aliphatic, acyclic alkene with at least one α,β-unsaturated carboxylic acid in water-dispersed form, and a curing system. In a preferred embodiment of the method, the application of a primer coating can be dispensed with entirely when water-soluble compounds of the elements Zr and/or Ti in the lacquer are used as the curing system.

主权项

1. A method for manufacturing a coated can lid from an aluminum strip, comprising:
1) initially applying a lacquer formulation to an aluminum strip and curing said lacquer formulation thereon; wherein the lacquer formulation is a water-based lacquer comprising, in addition to water, components:
a) a copolymer or a copolymer mixture of at least one aliphatic, acyclic alkene with at least one α,β-unsaturated carboxylic acid in water-dispersed form, wherein the copolymer or the copolymer mixture has acid groups that are at least 20% neutralized, but not more than 60% neutralized, and has an acid number of at least 20 mg KOH/g but not greater than 200 mg KOH/g; andb) at least one water-soluble curing agent, wherein dispersed polymeric components of the water-based lacquer have a D50 value of less than 1 μm; and 2) after step 1) punching lid material from the aluminum strip and forming the lid material into a can lid.