🧩 PA+FR – Flame Retardant Polyamide
(Technical polyamide treated with flame retardant agents to resist ignition and delay fire propagation. Used in electrical components, housings, sensors, and safety parts.)
🔹 What is PA+FR
PA+FR is a polyamide (PA6 or PA66) modified with flame retardant additives that prevent combustion or self-extension of the flame. These additives can be halogenated (with bromine) or halogen-free (phosphoric, melamine). The material maintains the toughness of polyamide while offering high electrical and thermal safety, which is why it is common in connector housings and electrical parts.
🔧 Composition
- Polyamide (PA6 / PA66): 70–80 %
- Flame Retardant Additives: 10–25 %
- Density: 1.30–1.45 g/cm³
- Melting Point: ≈ 250–260 °C
- Flammability Class: UL94 V-0 / V-2
- Continuous Heat Resistance: 110–130 °C
🚗 Where PA+FR is used in the automotive industry
| Component | Example parts | Observations |
| Electrical Systems | Connector housings, relays | Flame retardant, high insulation |
| Engine Bay | Sensor covers, brackets | Resistant to flame and heat |
| Safety Systems | Short-circuit risk parts | Prevents auto-ignition |
| Technical Interior | Fuse boxes, electric covers | Rigid, safe, and thermally stable |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 250 – 270 °C | Controlled melting, specific FR odor |
| Heat Plate (Mirror) | 240 – 260 °C | Clean joint without burning |
| Manual Extrusion | 240 – 260 °C | Suitable for large housings |
🔩 What to Weld PA+FR With (Material Compatibility)
PA+FR welds well with standard polyamides, but mixing with materials that melt differently should be avoided.
✅ Compatible with:
- PA+FR ↔ PA6 / PA66 / PA+GF / PA+MD / PC+PA – very good.
- PA+FR ↔ PBT / PC+PBT / HTN / PPA – partially compatible.
❌ Incompatible with:
- PP, PE, PVC, PS, ABS, ASA – different melting points.
💡 ReplastMD Recommendation:
Use PA66 or PA+FR rods at 260 °C. Maintain moderate airflow, avoiding overheating — FR additives can release gases and form bubbles. After welding, smooth the area with a short hot air pass for a uniform finish.
🏭 Manufacturers and Trade Names
- BASF: Ultramid® FR
- DuPont: Zytel® FR
- Solvay: Amodel® FR
🧠 How to Identify PA+FR
- Engraved marking: >PA66-FR<, >PA6-FR<, >V-0<, >UL94<.
- Semi-matte surface, rigid, slightly porous.
- Flame extinguishes quickly or does not propagate.
- ReplastMD practical test: If the part does not support a flame and is marked >FR< / >V-0<, it is confirmed Flame Retardant Polyamide.
🛠️ PA+FR Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PA+FR welding for fuse boxes, ECU housings, and electrical connectors, ensuring a safe and durable result.