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| Synonyms:Zinc octadecanoate Zinc distearate Stearic acid zinc salt Octadecanoic acid zinc salt Zinc soap Metallic stearate (Zinc) Molecular Formula:C36H70O4Zn Molecular Weight: 632.33 HS Code: 3824999999 Grade:98% Industrial grade Hazard Class:General Cargo | |||||||||
557-05-1
bosschem
557-05-1
Zinc stearate, also known as zinc stearate (or zinc octadecanoate or zinc distearate), is a metallic soap compound formed by the combination of stearic acid and zinc. Its chemical formula is usually written as:
Zn(C18H35O2)2 (C36H70O4Zn, CAS No.: 557-05-1, molecular weight approximately 632.33)
It is a white, light, fine powder at room temperature with a pleasant odor. Its density is approximately 1.10 g/cm³, melting point is approximately 120-130℃, and temperature resistance can reach around 260℃. Zinc stearate is insoluble in water, ethanol, and ether, but soluble in hot ethanol, turpentine, benzene, toluene, and other organic solvents and acids. When heated and dissolved in an organic solvent, it becomes a gel upon cooling. It decomposes in strong acids into stearic acid and the corresponding zinc salt. Commercially available zinc stearate is usually a mixture of zinc stearate and zinc palmitate, containing a small amount of excess zinc oxide (approximately 12.5%-15%).
Zinc stearate is a common metal soap, which is, from the point of view of molecular arrangement, composed of one zinc ion (Zn2+) and two stearate groups (C18H35O2-). The long-chain fatty acids give it excellent lubricity and compatibility with plastics and rubber, and zinc ion provides thermal stabilisation. The dual function of "lubrication + stabilisation" provides the structural basis for its wide application in the industries of plastics, rubber and coatings.
Chemically, zinc stearate is stable, non-toxic, and hydrophobic. It has low hygroscopicity in the air, but may absorb moisture and clump if stored for a long time, so moisture protection is necessary. It will decompose upon contact with strong acids. It should be stored in a dry and sealed environment.
Industrial-grade zinc stearate refers to products primarily intended for industrial production and is an important additive in industries such as plastics, rubber, and coatings. Compared to reagent-grade and other specifications, industrial-grade products place greater emphasis on the following indicators:
The zinc oxide content (approximately 12.5%~15%) reflects the product composition and purity, directly affecting stability and lubrication performance, and must meet specifications.
Melting point (approximately 120~130℃) is a classic indicator for judging product quality, and it must meet the specifications.
The content of free fatty acids affects product purity and downstream applications, and needs to be controlled at a low level.
Excessive moisture content can affect dispersibility and storage stability, so it needs to be kept at a low level and protected from moisture.
Fineness (powder particle size) affects dispersibility and performance; the mesh size must be controlled according to the intended use.
Zinc stearate is the most commonly used lubricant and mold release agent in plastics processing. It has good compatibility with the plastic matrix, can reduce friction between materials and equipment, and prevent products from sticking to the mold. It is widely used in injection molding, extrusion and compression molding of styrene resin, phenolic resin, amino resin, etc.
Zinc stearate is a non-toxic heat stabilizer for PVC. It can inhibit initial coloring and provide good lubricity. The calcium-zinc composite stabilizing system formed by combining zinc stearate and calcium stearate is the mainstream of environmentally friendly stabilizers and is widely used in the production of non-toxic products such as PVC pipes, profiles, wires and cables, and food packaging films.
Zinc stearate is used as a release agent, activator, plasticizer and softener in the processing of natural rubber, synthetic rubber and latex. It can act as an acid activator and improve the processing performance of rubber compounds. It is used in the production of rubber products such as tires, rubber shoes, and seals.
Zinc stearate is used as a matting agent (de-gloss agent) and sanding aid in paints and coatings to help achieve a uniform matte finish and good sanding performance. It is applied in wood coatings, industrial paints and powder coatings.
Zinc stearate is used as lubricant and release agent in powder metallurgy pressing and moulding. It is used in the production of metal powder products, can reduce the friction between powder and mould, improve the density of pressed blank and the quality of demoulding .
Zinc stearate is used as a lubricant and powder lubricant in cosmetics, and may be found in the formulations of powder cosmetics such as talcum powder and pressed powder.
Its applications, including paper coating lubricants and grease thickeners, continue to expand.
Zinc stearate (zinc octadecanoate) is a kind of white light powder metal soap, with good lubricity and thermal stability, and is one of the most commonly used additives in plastic and rubber processing. In our daily life it is encountered indirectly through the supply chains of plastic products, rubber products, PVC products, paints and wood coatings and cosmetics. In industry, zinc stearate of industrial grade is widely used as a lubricant and release agent (core) in plastics processing, a calcium-zinc composite heat stabiliser for PVC, a release agent and activator in rubber processing, a finishing and polishing aid in paints, a lubricant in powder metallurgy, and a lubricating auxiliary material. "daily use" and "plastics, rubber, paints and powder metallurgy" combine in a critical metallic soap additive.
