Sodium stearate is a stabiliser and thickener that helps harden soaps and naked deodorants, allowing a wide variety of shapes and sizes and removing the need for unnecessary packaging and synthetic preservatives. It also has opacifying properties that give foam a creamy white appearance.
Characteristic of soaps, sodium stearate has both hydrophilic and hydrophobic parts, the carboxylate and the long hydrocarbon chain, respectively. These two chemically different components induce the formation of micelles, which present the hydrophilic heads outwards and their hydrophobic (hydrocarbon) tails inwards, providing a lipophilic environment for hydrophobic compounds.
The tail part dissolves the grease (or) dirt and forms the micelle. It is also used in the pharmaceutical industry as a surfactant to aid the solubility of hydrophobic compounds in the production of various mouth foams.
Sodium stearate is produced as a major component of soap upon saponification of oils and fats. The percentage of the sodium stearate depends on the ingredient fats. Tallow is especially high in stearic acid content (as the triglyceride), whereas most fats only contain a few percent. The idealized equation for the formation of sodium stearate from stearin (the triglyceride of stearic acid) follows:
Purified sodium stearate can be made by neutralizing stearic acid with sodium hydroxide.
Sodium stearates are used as lubricants, surfactants, emulsifiers, waterproof agents, and gelling agents in personal care, cosmetics, rubber, polymer and food applications. Their key end use lies in the manufacture of deodorant sticks, facial soaps, lotions and ointments.
As mention in last part Sodium stearate is used in various industries and is used as a highly functional ingredient in cosmetic formulations, as well as in the pharmaceutical industry as a surfactant to help dissolve hydrophobic compounds, including industries that use sodium stearate mention in following:
- Cooking agent in latex rubber and raw rubber industries
- Manufacture of detergents
- In various industries as a surfactant
- In the plating industry, for ease of forging
- Production of plastic as a softener
- Production of fireworks and candles
- Lubricant production
- Prevent metal oxidation
- In the pharmaceutical industry for drug release systems
- Fire extinguishers