Effect of functionalised core-shell microgels prepared by emulsion polymerisation on acrylic coatings properties

The influence of hydroxyl-functionalised acrylic core-shell microgels incorporated into a solvent-borne acrylic binder system on the properties of coatings is described in this paper. Our approach has been to show the usefulness of prepared functionalised microgels as coating modifiers. This subject was shown to be connected with the selection of an appropriate solvent with good affinity for microgels and the film-forming polymer. Therefore the swelling behaviour of microgels in selected solvents as a function of microgel composition is discussed as well. The structured microgels were prepared by first making an aqueous emulsion via the semi-batch emulsion copolymerisation, then dehydrating the system by air drying followed by grinding in a mill. The resulting agglomerates of spherical microgel particles were dispersed in convenient organic solvent media and after that added to the thermosetting solvent-borne acrylic binder system. It was shown that the application of core-shell microgels did not affect the surface appearance and transparency of coatings. Moreover, the presence of microgel network precursors improved corrosion resistance of coatings. (C) 2008 Elsevier B.V. All rights reserved.