What is stearic acid
Stearic acid, chemical formula C18H36O2, molecular weight 284.48, is a compound, octadecanoic acid. Produced by hydrolysis of oil.
Almost all oils have varying levels of stearic acid, the content of which is higher in animal fats, such as butter, the content of which can reach 24%, the content of vegetable oil is less, tea oil is 0.8%, palm oil is 6%, but the content of cocoa butter is as high as 34%.
Function and efficacy of stearic acid
1, stearic acid is mainly used in the production of stearate: sodium stearate, magnesium stearate, calcium stearate, lead stearate, aluminum stearate, cadmium stearate, iron stearate, potassium stearate.
2, stearic acid is widely used in the manufacture of cosmetics, plastic cold-resistant plasticizers, release agents, stabilizers, surfactants, rubber vulcanization accelerator, water repellent, polish, metal soap, metal mineral flotation agents, softeners, pharmaceuticals and other organic chemicals.
3, stearic acid can also be used as an oil soluble pigment solvent, crayon smoothing agent, wax paper polishing agent, stearic acid glycerin emulsifier.
4, stearic acid is used in the food industry as a lubricant, defoamer and food additives stearate glycerin, stearate sorbitan anhydride ester, sucrose ester and other raw materials. Used as auxiliary raw materials and raw materials for daily chemical products.
5, stearic acid is widely used in PVC plastic pipe, plate, profile, film manufacturing. It is a PVC heat stabilizer with good lubricity and good light and heat stability. In plastic PVC pipes, stearic acid helps to prevent "coking" during processing, and is an effective heat stabilizer added in PVC film processing, while preventing discoloration of the finished film caused by exposure to sulfide.
6, stearic acid plays an important role in the synthesis and processing of rubber. Stearic acid is a vulcanizing active agent widely used in natural gums, synthetic rubber and latex, and can also be used as a plasticizer and softener. In the production of synthetic rubber process need to add stearic acid as emulsifier, in the manufacture of foam rubber, stearic acid can be used as a foaming agent, stearic acid can also be used as rubber products release agent.
Stearic acid synthesis method
1. Fractionation method.
2, pressing method, animal and plant oil as raw materials, in the presence of hydrolytic agents (such as zinc oxide) through high pressure hydrolysis, washing, vacuum distillation, pressing, bleaching crystallization and other processes to produce a stearic acid.
3, in the presence of the decomposition agent (benzene, naphthalene and other sulfonated mixture), the hardening oil, cattle fat or sheep fat for hydrolysis, and then through acidification, distillation, pressing, pickling decolorization to obtain the finished product.
4, with oleic acid hydrogenation method.
5, with synthetic fatty acid C10 ~ C20 and C18 ~ C20 fractions as raw materials through melting, pickling (with 1% sulfuric acid) casting, pressing, melting, pickling, dehydration crystallization.
Is stearic acid harmful to skin
Stearic acid is not obviously harmful to the skin, because stearic acid is a common fatty acid, widely found in a variety of oils. The use of cosmetics mainly plays the role of lubrication and emulsification. Therefore, many cosmetics contain other compounds of stearic acid, which has no obvious harm and irritation to the skin, as long as the content is within a standardized range.