🧩 KYNAR – Polyvinylidene Fluoride (PVDF)
(High-performance fluoropolymer recognized for its exceptional chemical, thermal, and UV resistance. Kynar® is an inherently flame-retardant and hydrophobic material, stable in the most aggressive environments.)
🔹 What is Kynar (PVDF)
PVDF is a semi-crystalline fluorinated polymer. At ReplastMD, we treat Kynar as the ultimate barrier material. It is used where other plastics fail—specifically in fuel lines, chemical valves, and high-temp wire insulation (up to 150 °C). Its high density and chemical inertness make it the gold standard for parts exposed to ethanol, biodiesel, and ozone.
🔧 Composition & Properties
- Polymer Base: Polyvinylidene fluoride (PVDF).
- Density: ~1.77 – 1.80 g/cm³ (very dense).
- Melting Point: ~170 – 175 °C.
- Operating Range: Up to +150 °C.
- Chemical Resistance: Exceptional (acids, fuels, solvents).
🚗 Where it is used in the automotive industry
| Component | Example parts | Observations |
| Fuel & Brake Lines | VW, Peugeot, Toyota | Chemical and vapor diffusion barrier |
| Fittings & Valves | Bosch, Delphi canisters | Ethanol and biodiesel resistance |
| Wire Insulation | Valeo, Siemens wiring | UV and thermal stability |
| Coatings | Kynar 500® industrial paint | Anti-UV protection, 20+ years life |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | ✅ 330 – 360 °C | Requires clean, dry air |
| Heat Plate (Mirror) | ✅ Ideal | Clean joints without oxidation |
| Extrusion | ✅ Recommended | Use matching PVDF welding rod |
| Ultrasonic | ⚠️ Limited | Only for thin-walled parts (< 2 mm) |
💡 ReplastMD Recommendation: Weld at ~350 °C using a Kynar PVDF rod. Avoid any surface contamination from oils or dust, as PVDF is highly inert and requires surgically clean surfaces for an effective, high-pressure weld.