A sodium salt of stearic acid, which is used as a release agent for sticks and other products, and also serves as a gelling agent and thickener. Sodium stearate has a low melting point and is readily soluble in fatty oils, fats and waxes. It can be found in many cosmetics and soaps, as well as in some paints and rubbers. It is also used as a food additive and in some pharmaceuticals.
Sodium stearate is produced by saponification of natural fats and oils. The most common sources of the fatty acids needed for this process are vegetable triglycerides such as coconut and palm oils and animal triglycerides from tallow. These triglycerides are first processed through catalytic hydrogenation to form saturated fatty acids of 18 carbon atoms. These saturated fatty acids are then saponified to form the stearates which are later used in soaps and other products.
The invention relates to solutions of alkali metal stearates that remain stable at room temperature, and further to the use of these stearate solution compositions in lubricant formulations. The compositions of the invention may be delivered in neat form, or in emulsions. In the latter case, the stearates can be formulated with any water soluble nonionic surfactant as long as the surfactant is present in at least a 1:1 weight ratio with the alkali metal stearates. The invention further relates to the use of electrolytes (component (C)), such as sodium hydroxide, potassium hydroxide and sodium borate, that do not delearn the stearate solution, when these electrolytes are diluted with an amount of water sufficient to reach a pH value of about 6.5.