Powder coating useful as a mat coating

Containing powder coatings(a) an epoxy resin,(b) at least one polycarboxylic acid of the formula I or II in which R¹, R², R³ and R⁴ independently of one another each represent a hydrogen atom, C₁-C₄-alkyl or the radical -CH₂-CH₂-COOH, R⁵ and R⁶ independently of one another each represent a hydrogen atom, C₁-C₄-alkyl, the radical -CH₂- CH₂-COOH or together denote an unsubstituted or alkyl-substituted methylene or polymethylene group having 1 to 7 carbon atoms, where at least two of the substituents R¹ to R⁶ are the radical -CH₂-CH₂-COOH, the substituents R independently of one another for a hydrogen atom or the wherein the ratio of the carboxyl groups contained in the 2-Carboxylcyclohexancarbonylrest to the RO groups is 0.5 to 1.0, m is a number from 2 to 5, n has a value of zero to 10 and X for a direct bond, an aliphatic or cycloaliphatic radical, and (c) a carboxyl-terminated saturated polyester, tolylbiguanide or dicyandiamide, are suitable for the production of matt coatings on surfaces, in particular of metals.