| Stearic Acid | General Topic Information | Stearic acid is a saturated 18-carbon length fatty acid that is derived from animal or plant feedstock, fats, and oils. Manufacturers use stearic acid in more than 3,200 skin, hair, and cosmetics products in the United States. These products include soaps...view more Stearic acid is a saturated 18-carbon length fatty acid that is derived from animal or plant feedstock, fats, and oils. Manufacturers use stearic acid in more than 3,200 skin, hair, and cosmetics products in the United States. These products include soaps, shampoos, greases, oils, candles, foods, rubber, and metalworking fluids. Manufacturers use stearic acid for its cleansing properties, as well as for use as a thickening agent and surfactant. The main ways formulations make use of stearic acid are as solvents, surfactants, and cleansers. Stearic acid is especially suited for these purposes because of its bifunctional character. Stearic acid has a polar head group that attaches easily to metal cations as well as a non-polar chain that allows for solubility in organic solvents. This bifunctional combination enables stearic acid to work as a surfactant and softening agent. Manufacturers also use stearic acid as an element for hardening or thickening. In bar soap, for example, it is the stearic acid that helps the solution solidify into bar form. Candles, oil pastel paints, and hard candies also use stearic acid to maintain their shapes. Stearic acid is an emulsifier, meaning it binds together materials that would typically separate (such as oil and water). This can prevent product ingredients from separating and clumping up, helping them to stay solid, smooth, and creamy. Items containing stearic acid typically require less shaking to mix ingredients prior to use. view less |
