Lithopone for Masterbatch: A Cost-Effective White Pigment for Plastics
Introduction
Lithopone (ZnS·BaSO₄), also known as zinc barium white, is a widely used white inorganic pigment in plastic masterbatch production. Due to its high opacity, bright whiteness, and low cost, it serves as a budget-friendly alternative to Titanium Dioxide (TiO₂). Although it has poor weather resistance, surface modification techniques can improve its performance in plastic applications.
The demand for masterbatch-grade inorganic pigments (TiO₂ & Lithopone) is growing at over 25% annually, driven by the expanding plastics industry.
Lithopone vs. Titanium Dioxide (TiO₂) in Masterbatch
| Property | Lithopone | Titanium Dioxide (TiO2) |
| Opacity | High (but lower than TiO₂) | Excellent |
| Weather Resistance | Poor (grays under UV) | Excellent |
| Cost | Low (cost-effective) | High |
| Common Use | Blended with TiO₂ to reduce costs | Premium applications |
Masterbatch Basics: Definition & Composition
1. What is Masterbatch?
Masterbatch is a high-concentration coloring agent made by dispersing pigments (TiO₂, Lithopone, etc.) or additives into a thermoPlastic Resin carrier.
2. Common Plastic Coloring Methods
· Dry Blending: Directly mixing raw resin with powdered pigments (e.g., TiO₂, Lithopone).
· Color Compounding: Pre-mixing pigments with resin to create colored plastic pellets.
· Masterbatch Coloring (Most Popular): Using pre-dispersed pigment pellets for uniform coloring.
3. Advantages of Masterbatch Coloring
·Better Dispersion – Prevents speckles and uneven coloring.
· Cost-Efficient – Reduces waste and improves production speed.
· Multi-Functional – Can include UV stabilizers, antistatic agents, etc.
4. Key Requirements for Masterbatch Pigments
· Heat Stability – Must withstand processing temperatures.
· Lightfastness – Should not fade under UV exposure.
· Good Dispersion – Ensures uniform color distribution.
· Non-Migratory – Prevents color bleeding in final products.
Why Use Lithopone in Masterbatch?
✅ Cost Savings – Up to 50% cheaper than TiO₂.
✅ High Opacity – Excellent whiteness and coverage.
✅ Easy to Disperse – Works well with PE, PP, PVC, and ABS resins.
Challenges & Solutions
❌ Poor Weather Resistance → Surface modification improves UV stability.
❌ Lower Heat Resistance → Used in low-to-medium temperature applications.
How to Choose the Right Lithopone for Masterbatch?
✔ High ZnS Content (≥30% for better opacity).
✔ Fine Particle Size (improves dispersion).
✔ Surface-Modified Grades (enhances compatibility with plastics).
✔ Low Heavy Metal Content (ensures safety for food-contact applications).
Conclusion
Lithopone remains a cost-efficient white pigment for plastic masterbatches, especially when blended with TiO₂. While titanium dioxide offers superior performance, Lithopone helps reduce production costs without sacrificing quality in many applications.
For High-Quality Lithopone masterbatch pigments, consult trusted suppliers specializing in plastic-grade pigments.