aluminum distearate is an aluminium salt of stearic acid and functions as a thickening agent. It is a fine white powder that has a slight fatty odor. It is very hydrophobic, making it good for coating and lubricating oils. It is also an excellent emulsion stabilizer and viscosity increasing agent. It is considered non-irritating, nontoxic and is noncarcinogenic. It is compatible with a wide variety of materials. It can be used as a metal rust inhibitor, building material waterproofing agent and paint and ink thickener. It can also be used as a plastic and rope lubricant. It can also be combined with aromatic and aliphatic hydrocarbons to form a gel.
When used in oil paints, aluminum stearate helps suspend pigments, prevent settling and thickens the paint. It also helps the paint gel quickly with the oil, reducing the amount of oil needed to wet the pigments. It also helps the paint to retain its luster and clarity for longer periods of time.
Like other stearate salts (Lithium Stearate, Calcium Stearate, Magnesium Stearate and Zinc Stearate) Aluminum stearate is often referred to as a “metal soap” because it coats the surface of pigment particles to help keep them in suspension. In a series of tests conducted by Gardner, these metal soaps helped to prevent the separation of oil and pigments and reduced the amount of oil required to wet the pigment. These effects are due to steric interactions between the surface of the pigment particles and the stearate salts, which keep them from adhering to each other (Gardner 1930). American Elements supplies this material in both vegetable and tallow based grades and it meets applicable food and pharmaceutical testing standards.