In this study, aluminium pigments were encapsulated with hydroxyl group-containing acrylic resin after surface acid treatment to enhance their adhesive performance in the paint film. The removal efficiency of fatty acid on surface of aluminium particles was studied by means of thermogravimetric analysis and the effect of acid treatment on adhesive performance of aluminium pigments encapsulated with hydroxyl group-containing acrylic resin in the paint film was investigated by pulling-off tests. It was found that fatty acid on surface of aluminium particles was removed efficiently by acid ethanol solution, and then hydroxyl group-containing acrylic resin can be encapsulated onto the surface of the aluminium particles by chemisorptions. The encapsulated aluminium pigments have excellent adhesive performance in the paint film. (c) 2011 Canadian Society for Chemical Engineering