Acrylic Dispersions for Industrial Coatings with Polymer-Bound Stabilizers
Acrylic dispersions, consisting of particles with a controlled morphology and a self-crosslinking mechanism, are the current state-of-the art binders for VOC-compliant industrial coatings for wood, metal and plastics. The process of emulsion polymerization is used in producing these acrylic dispersions. Emulsion free-radical polymerization is an environmentally friendly method for the production of a wide range of polymeric dispersions. In the emulsion polymerization process, monomer is polymerized in an aqueous medium containing surfactant micelles. Surfactant plays a dual role in the process; it not only provides the locus of polymerization but also stabilizes the polymer particles.
Recent changes in the regulations concerning the emission of organic solvents in the European community have led to a growing interest in the use of polymer dispersions in high-performance waterborne coatings systems. One-pack systems, using the current state-of-the-art technology of combining carbonyl-hydrazide crosslinking with control of the morphology of the particles in the polymeric dispersion, have been studied extensively.1,2 These acrylic dispersions are synthesized using conventional surfactants as an integral part of the recipe. Even though some grafting might occur during the polymerization, the surfactants are predominantly adsorbed onto the surface of the polymer particles.3