Stearic acid, or octadecanoic acid according to IUPAC (C17H35CO2H), is a saturated fatty acid whose name comes from the Greek word στέαρ “stéar”, which means tallow. Being the most abundant fatty acid in nature after palmitic. This acid is also known as stearin.
It is a cheap raw material due to its abundance in nature and, as it is completely innocuous, it becomes a product widely used in cosmetics, pharmacy, plastics, soaps and many other industries.
It is obtained through the hydrolysis of different vegetable and animal oils and fats. Adplast supplies stearic acid of vegetable and animal origin.
Adding between 0.3-1.0% stearic acid acts as a solid lubricant, remaining stable at high temperatures and improving the following manufacturing points:
high temperature spots
Raw material savings
It is used in the tire industry, as well as in the rubber industry, in different concentrations together with other substances in order to control the flexibility or other properties of the final product.
Accelerates the vulcanization process.
The liquid or solid stearic acid can be melted and used for surface treatment of parts and materials, in order to avoid their oxidation, hardening, adhesions or their becoming wet.
It is also used in combination with waxes and resins to improve the protective properties of raw materials and end products. The “greasy” part of stearic acid repels water and creates an insulating layer on the product.
It is used to control acidity in very alkaline soaps and acts as an emulsifier, giving hardness to the mixture. It is also used in fabric softeners and as a defoamer.
It has good properties as an emulsion stabilizer and thickener. It also gives cosmetics a soft, refreshing feel to the skin.
A curious application is that of being one of the raw materials together with calcium stearate in plasticine.
Stearic Acid is used by candle makers in some applications:
A small dose of stearic acid in the candle mix also fixes the candle scent longer, preventing aroma migration.
The addition of amounts of stearic acid together with the paraffin and the rest of the products is used to modify the candle’s melting point. This use is intended to improve the properties when stored with heat or to maintain the shape of the candle when lit.
Stearic acid also helps to improve the appearance and opacity of candles.
In some formulations, this material acts as a repellent for rodents and other animals that can affect crops and plants.
Stearic acid, in nature, is generated by the decomposition or degradation of animal fats, to which these animals associate it with death and putrefaction, staying away.
It is used as a coating for metallic powders to prevent oxidation and to be able to store them for long periods of time.
This insulating property is also used on hygroscopic solids to prevent moisture absorption and improve service life.