Aluminum Stearate

Chemical properties

Aluminum stearate is a white, wax-like powder (metallic soap) that dissolves in mineral spirits or hot oil. A small amount (2% or less) added to oil paint imparts a short, buttery consistency. It eliminates the separation of pigment and oil, thickens varnishes considerably.

The Uses of Aluminum Stearate

aluminum stearate is a saline form of stearic acid used as a thickener and emulsifier, and to regulate the stability and suspension of a cosmetic formulation.

The Uses of Aluminum Stearate

Waterproofing fabrics, ropes; in paint and varnish driers; thickening lubricating oils; in cements; in light-sensitive photographic compositions.

The Uses of Aluminum Stearate

Aluminum stearate is used for waterproofing fabrics and for thickening lubricating oils. It is involved in the preparation of polyamides and thermosetting plastics. It is used as a waterproofing additive in cements and in light-sensitive photographic compositions. It acts as a gelling agent for alkyd paints, as a defoamer for oil drilling fluids and as a retarder for polysulfide dental impression materials. Further, it is used in greases, lubricants, cutting compounds, cosmetics and pharmaceuticals. It serves as a flatting agent, as a defoaming agent in beet sugar and yeast processing. In addition to this, it is used as a water-repellent soap for natural stone surfaces.

Definition

ChEBI: Aluminium tristearate is an aluminium salt. It contains an octadecanoate.

Usage

Aluminum stearate dissolves in vegetable oils on heating and if a high enough concentration of the soap is used, gelling occurs on cooling. In the usual practice of making paints, the aluminum stearate is ground with the pigment before the bulk of the oil is added. To prepare a concentrated solution (10% w/v), add 100 grams of aluminum stearate (nearly fills a half liter measuring cup without compacting) to one liter of linseed oil. Heat the oil to about 150° C. and gradually slowly adding the white powder to the hot oil with stirring. Add one part of this solution to four parts of oil by weight of oil before adding to pigments and grinding.