Powder coating

1. Powder Coating Application Process

1. Edge Coverage
   Add 0.5%–1.0% polyethylene wax, polyvinyl butyral, or anti-flow agents such as silica to ensure uniform coating on edges and corners, preventing shrinkage or buildup.

2. Preventing Lumps
   Lumps are caused by clumped powder, poor atomization, or metallic pigment accumulation. Add fine alumina (Al₂O₃), silica (SiO₂), or anti-caking agents to improve flow.

3. Surface Defects
   Raised particles may result from unmelted inorganics or gelled organics, while craters are often caused by resin incompatibility or contamination. Select compatible raw materials and maintain a clean spraying environment.

4. Pigment Coverage Tips

• Black: 0.5%–1% carbon black + 0.2% phthalocyanine blue for tone

• White: 25% titanium dioxide + ultramarine or permanent violet

• Red: Increase resin content, add titanium dioxide and yellow pigment for brightness

2. Key Application Considerations

• Environment: Well-ventilated, ≤35°C, no open flames or direct sunlight

• Powder Check: Ensure powder is dry and free of clumps before spraying

• Operator Safety: Wear protective clothing; avoid prolonged skin contact; wash with soap if contact occurs

• Static Grounding: Fully ground spraying equipment to prevent static interference and ensure proper coating adhesion

3. Clumping Prevention Strategies

1. Formulation Optimization
   Reduce low glass transition temperature (Tg) polymers like leveling agents to maintain higher Tg in the powder system.

2. Resin Improvement
   Select alcohols or acids that increase Tg during polyester resin production.

3. Add Anti-Caking Agents
   Incorporate 0.2%–0.5% nano silica or nano alumina to prevent particle adhesion and improve flow, especially in high-humidity, high-temperature environments.

4. Production Control
   Cool broken chip material thoroughly before grinding. Reduce feed rate, increase airflow, and use cooled air intake to control grinding temperature. Forced cooling before grinding is more effective than air-conditioning alone.

4. Conclusion

Successful powder coating application and clump prevention require a holistic approach—optimizing formulation, controlling the environment, and implementing strict production standards. By following these methods, you can ensure a smooth, durable, and defect-free finish.