Highly curable coating formulation for the inner surfaces of cans

The present invention relates to a water-based can inner coating based on a copolymer or a copolymer mixture of at least one aliphatic and acyclic alkene having at least one α,β-unsaturated carboxylic acid in water-dispersed form, wherein the can inner coating contains a water-soluble hardener selected from inorganic compounds of the elements Zr and/or Ti, so that the need for using organic hardener systems can be largely avoided. The present invention further relates to a method for the internal coating of white sheet or aluminum cans, in which the previously mentioned car inner coating is directly applied onto the metallic inner surfaces of the cans and cured without any need to carry out a conversion treatment for improving coating adhesion of the inner surfaces of the cans.