🧩 PVDF – Polyvinylidene Fluoride
(Semi-crystalline fluoroplastic recognized for exceptional chemical resistance, UV stability, and superior electrical insulation. PVDF is more rigid than FEP or PFA, yet easier to process and mechanically stronger.)
🔹 What is PVDF
PVDF (Polyvinylidene Fluoride) is a semi-crystalline fluorinated polymer derived from vinylidene fluoride. Known commercially as Kynar®, it offers a rare combination of chemical, mechanical, and thermal resistance while remaining easily injectable and weldable. Its low water absorption (<0.04%) and high tensile strength make it perfect for aggressive industrial and automotive environments.
🔧 Composition & Properties
- Base: 100% Polyvinylidene fluoride.
- Density: 1.76–1.80 g/cm³.
- Melting Point: 170–177 °C.
- Chemical Resistance: Total (oils, fuels, acids).
- Continuous Heat Resistance: 150–170 °C.
🚗 Where PVDF is used in the automotive industry
| Component | Example parts | Observations |
| Fuel / Oil Systems | Hoses, valves, fittings | Resists hydrocarbons and additives |
| Cooling / EGR | Housings, gaskets, pumps | Stable up to 170 °C |
| Electrical / Sensors | Cables, jackets, insulators | Excellent dielectric, UV stable |
| Chemical Applications | Pipes, gaskets, venturis | Inert to concentrated acids |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 250 – 270 °C | Uniform melting, clear flow |
| Heat Plate (Mirror) | 250 – 260 °C | Clean joint, bubble-free |
| Plastic Extrusion | 250 – 270 °C | PVDF or compatible FEP rods |
| Ultrasonic / Vibration | — | Applicable for thin, rigid parts |
🔩 Material Compatibility
- ✅ Compatible: PVDF, ECTFE, ETFE, FEP, PFA.
- ⚠️ Good Compatibility: PTFE (with chemical surface treatment).
- ❌ Incompatible: ABS, PP, PE, PC, PA, POM, PVC, PET.
💡 ReplastMD Recommendation: Use PVDF or FEP rods at 260 °C. Clean the surface thoroughly and use controlled hot air without oxidation. For chemical seals, maintain constant contact pressure during cooling.
🧠 How to Identify PVDF
- Engraved marking: >PVDF<, >KYNAR<, >SOLEF<, >TECAPVDF<.
- Texture: Glossy, rigid, smooth, milky-white or matte black.
- ReplastMD practical test: Heavy, rigid, and solvent-resistant. Softens at 160–170 °C without sudden warping. Flame self-extinguishes.
🛠️ PVDF Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PVDF welding for chemical fittings, hoses, and gaskets, ensuring a glossy, clean, and leak-proof finish.