Zinc Stearate is a white, fine powder widely used as a mold release agent, internal lubricant, and anti-block additive in thermoplastics. It is a zinc salt of stearic acid with excellent heat stability, low moisture absorption, and chemical inertness. Zinc stearate is compatible with most polymers, including PVC, PE, PP, ABS, and polyamides.
| Property | Typical Value |
|---|---|
| Appearance | White fine powder |
| Zinc Content | 10 – 12% |
| Free Fatty Acid | ≤ 1.5% |
| Moisture | ≤ 2.0% |
| Melting Point | 120 – 130 °C |
| Bulk Density | 200 – 300 g/L |
| Problem | Zinc Stearate Solution |
|---|---|
| Sticking to mold or die | Acts as release agent to avoid adhesion |
| High melt pressure during extrusion | Reduces internal friction and torque |
| Blocking in film rolls | Creates micro-spacing between layers |
| Poor pigment dispersion | Improves flow and pigment wetting |
Q1: Is zinc stearate safe for food contact?
Yes, food-grade versions are available upon request.
Q2: What is the recommended dosage?
Typical loading is 0.2% – 1.0%, depending on the formulation and processing type.
Q3: Can it replace calcium stearate?
Zinc stearate offers better mold release but less thermal stability. It depends on your formulation goals.
