The invention relates to a powder paint binder composition which contains a compound comprising carboxylic acid units, a compound comprising hydroxyalkyl amide units and as catalyst phosphinic acid, a (C1-C26) alkylphosphinic acid, a C6-C20) arylphosphinic acid or an ester or an anhydride derived from one of these acids. Highly suitable as catalyst for this reaction are phosphinic acid, phenylphosphinic acid and diylphosphine ester acid.
