Driers and Metallic Soaps

Metallic soaps are compounds of alkaline earth metals or heavy metals and monobasic carboxylic acids of 7 to 22 carbon atoms. It is usually convenient to include resinates (usually from rosin) and naphthenates in a discussion of metallic soaps. Their water insolubility differentiates metallic soaps from ordinary soaps. Their solubility or solvation in organic solvents accounts for their use in paints. Commercial metallic soaps are made and used in solid, paste, and liquid forms. The form depends on the metal and its amount, the nature of the organic acid, and the presence or absence of solvents or additives during manufacture. Metals of low atomic weight usually form soaps of high melting points. Long, straight chain, or saturated fatty acids form soaps of higher melting points than do short or branched chains, or unsaturated acids. Soaps made by precipitation are likely to be light fluffy powders. Soaps made by fusion are hard dense solids. Liquid and paste forms are solutions or suspensions in petroleum or other solvents.