Process for lowering the emission of formaldehyde in acid-cured lacquers based on alkyde resin and urea resin combinations

摘要

A process for reducing the free formaldehyde content and the emission of formaldehyde in acid-curing surface coatings based on alkyd resin/urea resin combinations in which C-H-acidic compounds which contain in the molecule one acidic alpha-methylene group and one nitrogen atom in the form of an amide bond are added as solids. Addition of from 0.2 to 10% by weight (based on the solids content of the alkyd resin/urea resin combination) of the compounds claimed according to the invention, preferably of cyanoacetamide or acetoacetamide (in each case in 30% strength by weight solution in ethanol), significantly reduces the free formaldehyde content and the emission of formaldehyde without causing haze or reduced shelf life of the coating material or pitting and reduction in gloss in the coating film.