Inventive routes for the preparation of water-borne acrylic polyols for 2K PU protective topcoats

 
New regulations lead to a strongly increased demand for water-borne protective topcoats. However, matching the performance of solvent-borne 2K polyurethanes with low VOC water-borne systems remains a challenge for resin and paint producers.The two options to achieve the lowest possible VOC coatings, primary or secondary dispersions, present technical challenges in production. The emulsion polymerisation process to produce primary dispersions often faces problems of water-phase homopolymerisation of the hydroxyl bearing monomers. This causes poor stability of the emulsions and insufficient crosslinking of the final coatings. The removal of solvents to produce solvent-free polyols to be dispersed in water for secondary dispersions is also technically challenging. This paper shows two inventive routes using glycidyl neodecanoate to either facilitate emulsion polymerization or to simplify the secondary dispersion production processes, rendering both easier and more robust. In both cases, improved performance of the derived topcoat is observed.