🧩 PA612+EVOH – Polyamide 6.12 with Barrier Layer
(An advanced multi-layer material resulting from the combination of Polyamide 6.12 (PA612) and EVOH (ethylene-vinyl alcohol), widely used in automotive fuel and ventilation systems.)
🔹 What is PA612+EVOH
PA612+EVOH consists of co-extruded layers where the PA612 (a semi-crystalline aliphatic polyamide derived from bio-based sebacic acid) provides flexibility and low moisture absorption, while the EVOH core acts as an effective barrier against ethanol, petrol, and oxygen. This is the ideal solution for modern fuel lines (E10–E85) and tank ventilation systems requiring strict emission control.
🔧 Composition
| Layer | Material | Role |
| Outer / Inner | Polyamide 6.12 (PA612) | Flexibility, mechanical and chemical strength |
| Core (Intermediate) | EVOH | Vapor and oxygen barrier |
| Interlayer Adhesive | Modified Polyamide | Ensures bonding between PA and EVOH |
🚗 Where PA612+EVOH is used in the automotive industry
| Component | Example parts | Observations |
| Fuel / Ethanol Lines | VW, Ford, Renault | Perfect barrier against vapor diffusion |
| EGR Fittings / Joints | Toyota, Opel | Resistance to oils and moderate pressure |
| Tank Ventilation Tubes | Peugeot, Hyundai | Protection against oxygen and hydrocarbons |
| LPG / CNG Systems | Dacia, Fiat | High tightness and good flexibility |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 240 – 260 °C | Weld only on the outer PA612 layer |
| Plastic Extrusion | 250 °C | Recommended — use simple PA612 rod |
| Heat Plate (Mirror) | 240 – 250 °C | Warning: EVOH degrades above 260 °C |
🔩 Material Compatibility
- ✅ Compatible: PA612, PA610, PA12, PA612+EVOH.
- ⚠️ Partially Compatible: PA6, PA66, PA11 (requires fine-tuning).
- ❌ Incompatible: PP, PE, PVC (chemically and thermally incompatible).
💡 ReplastMD Recommendation: Weld only on the PA612 layer at ~250 °C using a PA612 rod. Do not attempt to melt the entire cross-section — the EVOH layer must remain intact to preserve its barrier function.
🧠 How to Identify PA612+EVOH
- Engraved marking: >PA612+EVOH<, >RILSAN TLO<, >VESTAMID D<.
- Texture: Soft, slightly glossy, highly flexible.
- ReplastMD practical test: Distinct layers visible in cross-section (PA-EVOH-PA). Flame: burns slowly with a faint ethylene scent.
🛠️ PA612+EVOH Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PA612+EVOH welding for fuel and LPG systems, ensuring a high-tech finish that prevents vapor leaks.