Halox BW-100 Barium phosphosilicate Halox Functional pigment Acrylic/Acrylate Resins Alkyd Resins Coatings >> Solventborne Coatings >> Waterborne Wood & Furniture Coatings Tannin stain inhibitors are dry pigments and liquid additives formulated into paint and coatings to stop the discoloration of a painted wood surface due to the migration of water-soluble tannic acids. The primary blocking mechanism employed by HALOX® for tannin stain inhibition is one of chelation (or precipitation). This chelation process is essentially the reaction of soluble metal cations from the pigment with phenol groups in the tannins. One of the major controlling factors in this reaction is the pH of the dry paint film. The pH of the dry paint film should be distinctly basic in nature (>8.0). At this basic pH, the phenol groups will react with the available metal cations. The pH of the dry paint film does not seem to have a measurable effect on the solubility of the tannins, but does control their reactivity. Because of this pH factor, we suggest that the paint be buffered through the use of high pH extenders. We have found that pigments such as platy talcs and calcium carbonate perform adequately for this application. The platy talc appears to perform best - probably due to the fact that it helps to lower the vapor transmission rate through the paint film. Tannin Stain Inhibiting Pigments and Additives HALOX BW-100 Phosphosilicate Acrylic Latexes Vinyl Acrylic Latexes Styrenated Acrylic Latexes Solvent Based Alkyds Phosphosilicate. Used as a tannin stain inhibitor in acrylic, vinyl acrylic and styrenated acrylic latexes and in solvent based alkyds for paint and coatings.