Fluorine-free low surface energy organic coating for anti-stain applications

Perfluorinated polymer material are widely used in various industries for their excellent amphiphobic properties while there is significant environmental concern on them recently. So US Environmental Protection Agency (EPA) regulations require new fluorine-free materials for anti-stain applications in leather, paper, textile, masonry, and homecare industries. Silicone materials are hydrophobic in nature but traditionally believed to be oleophilic. In this paper, it is demonstrated that by molecular design and tuning of surface energy, better oleophobicity could be obtained from silicone materials. For good amphiphobicity and instead of using fluoro-containg materials, tris-trimethylsily(M3T) unit was introduced into the polyacrylate as the functional side chain, to form M3T-containing copolyacrylate, the base polymer for the anti-stain application. By applying M3T copolyacrylate, fluorine-free silicone based material to masonry and fabrics, good anti-stain performance was achieved. The lowest surface energy of the silicone based copolymer is about 13 mN/M which is close to fluorine polymer. Research work has been done systematically on the effects of the ratio of M3T unit in the copolyacrylate, copolyacrylate concentration in coating formulation, copolyacrylate molecular weight, and solvents on coating anti-stain performance. Good anti-stain performance has been obtained on the treated substrate, while the copolyacrylate with molecular weight of 80,000 and concentration of 20 wt%, With increase of tris-trimethylsilypropyl methacrylate (M3T) ratio, the coating critic surface energy decreased, better anti-stain performance was achieved.