Zinc Stearate Zinc Stearate is a zinc salt of stearic acid, appearing as a fine, white, hydrophobic powder with a mild fatty odor. It is one of the most versatile metal stearates,
primarily used as a lubricant, release agent, and processing aid in various polymeric and industrial systems. Its unique chemical composition makes it insoluble in water but dispersible in non-polar media such as aromatic hydrocarbons and chlorinated solvents.
Known for its excellent lubrication, mold release, and anti-caking properties, Zinc Stearate plays a crucial role in enhancing processing efficiency and surface quality of finished products.
Key Properties
| Property | Value |
|---|---|
| Chemical Formula | C₃₆H₇₀O₄Zn |
| Appearance | Fine white powder |
| Melting Point | 120–130°C |
| Density | ~1.09 g/cm³ |
| Moisture | Typically <1% |
| Solubility | Insoluble in water; soluble in aromatic & chlorinated hydrocarbons |
| pH (5% in alcohol) | Neutral to slightly alkaline |
Applications of Zinc Stearate
1. Plastics and Polymers
- Acts as both an internal and external lubricant, especially in PVC processing.
- Prevents sticking to processing equipment, enhances flow, and improves surface finish.
- Reduces friction and wear during extrusion, molding, and calendaring.
2. Rubber and Elastomers
- Used as a release agent in rubber and polyurethane molding.
- Improves dispersion of fillers and pigments.
- Assists in preventing mold fouling and improving demolding efficiency.
3. Paints, Inks, and Coatings
- Serves as a flatting agent, imparting a matte or satin finish to paints and coatings.
- Improves abrasion resistance and enhances anti-settling properties in inks and pigments.
4. Cosmetics and Personal Care
- Used as a bulking and lubricating agent in face powders, foundations, and deodorants.
- Offers a silky, smooth feel and helps improve texture and adhesion to skin.
5. Pharmaceuticals
- Acts as a tablet and capsule lubricant to ensure smooth ejection during manufacturing.
- Used in ointments and topical creams for improved texture and stability.
6. Construction Chemicals
- Added to dry-mix products (e.g., tile adhesives, plasters) to improve water repellency and flowability.
Grades of Zinc Stearate
🔹 1. Technical Grade
- Standard industrial quality for use in plastics, rubber, paints, and coatings.
- Cost-effective and suitable for most non-food applications.
🔹 2. Pharma Grade (IP/BP/USP Compliant)
- Highly pure and free from heavy metals or harmful residues.
- Specifically developed for use in medicines, tablets, and cosmetic formulations.
🔹 3. Micronized Grade
- Ultra-fine particle size for better dispersion and uniform distribution in sensitive applications.
- Enhances clarity, smoothness, and surface quality in high-precision polymer and cosmetic products.
Packaging and Storage
- Typically supplied in 25 kg HDPE bags with liners or customized packaging options.
- Should be stored in a dry, well-ventilated area, away from moisture and heat.
- Shelf life: 12 to 24 months when stored under proper conditions.