1. Customer Background
The customer is a manufacturer of high-end electronic products, mainly producing headphones and game controllers. The product housings are made of HIPS plastic, which offers advantages such as low cost and easy processing. However, challenges include poor solvent resistance and a surface that is easily damaged.
2. Project Requirements
• Achieve a high-gloss silver finish on HIPS housings with a visual appearance close to metal electroplating;
• Ensure surface wear resistance, fingernail scratch resistance, and solvent resistance;
• Maintain stable mass-production performance with uniform film thickness, while ensuring that drying does not affect adhesion or gloss.
3. Solution
• Material Selection: Use electroplating-effect silver paint with a dedicated HIPS-resistant solvent-based resin system to prevent substrate cracking or burn-through;
• Primer Optimization: When the substrate color is dark or contains impurities, apply a white primer first to improve silver pigment reflectivity and achieve a brighter mirror-like effect;
• Surface Protection: Apply a UV clear coat or PU clear coat to improve wear resistance and scratch protection.
4. Implementation Process
• Pre-treatment: Clean the surface with alcohol to remove mold release agents, followed by flame treatment or primer application to increase surface polarity;
• Spraying Process:
- Mix electroplating-effect silver paste with burn-resistant PU resin at a specified ratio and dilute with mild solvents;
- Control the coating thickness at 10–15 μm to avoid cracking and uneven gloss;
- Bake at 60°C for 30 minutes at low temperature to ensure uniform drying;
• Clear Coating: Apply a protective clear coat to enhance wear resistance and surface feel.
5. Project Results
• Appearance: Uniform high-gloss silver finish with 20° gloss ≥85, visually close to metal electroplating;
• Adhesion: Cross-cut adhesion rating 5B, with no silver layer peeling;
• Solvent Resistance: No substrate exposure after 50 ethanol wipe cycles;
• Temperature & Humidity Resistance: No blistering or gloss loss after 80°C × 72h and 40°C / 95% RH × 96h cyclic testing;
• Substrate Protection: No cracking when bending or tapping the back side of HIPS; no substrate scorching or whitening observed.
6. Project Highlights
• Solves the challenges of poor solvent resistance and achieving a high-gloss mirror finish on HIPS substrates;
• Delivers high gloss, excellent wear resistance, environmental friendliness, and stable mass-production performance;
• Provides complete technical support to ensure production consistency in large-scale manufacturing.
