99% Industry grade Zinc stearate 557-05-1

1. What is Zinc stearate?

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 typical metal soap in molecular form, consisting of one zinc ion (Zn2+) and two stearate groups (C18H35O2-). The long-chain fatty acids provide hydrophobicity and excellent lubricity, and the zinc ion gives good safety and chemical stability, a property that makes it not only an industrial additive but also approved for use as a cosmetic ingredient, forming the structural basis for its application in the daily chemical and consumer goods industries.

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.

Non-industrial grade zinc stearate refers to products used in daily chemical and scientific research applications that are not for large-scale industrial applications. Compared to industrial grade, non-industrial grade products focus more on the following indicators:

Heavy metal limits (lead, arsenic, etc.)

used in cosmetics has strict limits on harmful impurities such as heavy metals, which is an important safety indicator.

Melting point

Melting point (approximately 120~130℃) is a classic indicator for judging product quality, and it must meet the specifications.

Moisture

Excessive moisture content can affect dispersibility and storage stability, so it needs to be kept at a low level and protected from moisture.

II. What are the uses of Zinc stearate?

1. Plastics processing lubricants and release agents (core application)

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.

2. Cosmetics and Daily Chemicals (Daily Chemical Grade)

In cosmetics, zinc stearate is used as a slip agent and powder lubricant, providing a smooth, delicate feel to the skin, especially in powder products such as talcum powder, pressed powder, and loose powder. Its use must comply with the Technical Specifications for the Safety of Cosmetics.

3.Household Lubrication and Maintenance (Consumer Grade)

Zinc stearate has excellent lubricity, and can be used as a household powder lubricant for the lubrication and maintenance of hardware such as door locks, slides and hinges, which can help reduce friction and eliminate abnormal noises.

4. PVC heat stabilizer

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.

5. Rubber processing aids

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.

6. Coating additives

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.

7. Powder metallurgy lubricants

Zinc stearate is used as a lubricant and release agent in powder metallurgy pressing and molding. It can reduce friction between powder and mold, improve the density of pressed blank and the quality of demolding, and is applied in the production of metal powder products.

8. Model making and handicrafts

Zinc stearate as a demolding and lubricant in model making and powder pressing processes helps craft enthusiasts to handle problems of moulding and demolding.

9. Scientific Research and Laboratory Applications (Reagent Grade)

Zinc stearate is a commonly used metal soap reagent in the laboratory. It can be used to study lubrication mechanisms, metal soap structure and surface chemistry, and is also a reference substance for zinc content determination in analytical chemistry.

10. Other Applications

With the development of daily chemical formulations, the application scope of non-industrial grade zinc stearate continues to expand, including teaching experiments, custom synthesis, and standard reagent supply.

It should be noted that non-industrial grade does not equate to "risk-free": inhalation of large amounts of zinc stearate dust may affect the respiratory system. Reagent-grade products should be used in accordance with laboratory safety regulations to avoid dust inhalation during experiments.

Summarize

Zinc stearate (zinc octadecanoate) is a white, lightweight, powdery metallic soap that combines excellent lubricity with good safety. It serves as both an industrial processing aid and a cosmetic ingredient. In daily life, we indirectly encounter it through plastic products, rubber products, PVC products, paints and wood coatings, and cosmetics. In non-industrial applications, zinc stearate is widely used as a cosmetic lubricant, in household lubrication and maintenance, in model making and handicrafts, and in scientific research laboratories. It is an important metallic soap product bridging "daily use" and "health, daily chemicals, and consumer goods."