🧩 PP+FR – Flame Retardant Polypropylene
(Thermally stable weldable plastic, treated for fire resistance, used in electrical parts and technical automotive components)
🔹 What is PP+FR
PP+FR (Flame Retardant) is a polypropylene infused with additives that prevent the spread of fire and reduce smoke emission.
It is used in applications where fire safety is critical — electrical parts, brackets, covers, and technical automotive components. It combines the mechanical properties of PP with self-extinguishing behavior according to UL94 V-0 / V-2 standards.
🔧 Composition
- PP (Polypropylene) – base matrix
- FR (Flame Retardant) – flame retardant additives (halogenated or halogen-free)
- Technical Additives – antioxidants, UV stabilizers, pigments
- Variants: PP-H+FR, PP-C+FR, PP-TD+FR (talc-filled and flame retardant)
🚗 Where PP+FR is used in the automotive industry
| Component | Example parts | Observations |
| Electrical Equipment | Battery covers, sensor housings, ECU modules | Fire resistant, thermally stable |
| Interior / Comfort | Heater casings, electrical consoles | Does not support combustion, matte finish |
| Engine Compartment | Covers, wiring fasteners, mounts | Withstands heat and flame |
| Other Applications | Industrial parts, fuse covers | Increased safety, good rigidity |
🔧 Welding temperatures and methods
| Method | Optimal temperature | Observations |
| Hot air | 260 – 280 °C | Controlled welding, slow melting |
| Heat plate (mirror) | 250 – 270 °C | Ideal for clean joints |
| Manual extrusion | 240 – 260 °C | For technical repairs and corners |
| Ultrasonic | — | Industrial use only |
🔩 What to weld PP+FR with (Material compatibility)
The question “what to weld PP+FR with” is very important — the material has a special composition, thus requiring an identical PP+FR rod or compatible material.
Flame retardants can change the melting point and adhesion, but general compatibility remains within the PP family.
✅ Compatible:
- PP+FR ↔ PP+FR – ideal combination, stable joint
- PP+FR ↔ PP-H / PP-C – partially compatible, but fire-retardant properties are lost after welding
- PP+FR ↔ PP-TD / PP-MD – moderate compatibility
- PP+FR ↔ PP+FR (other brands) – compatible if bases are similar
❌ Incompatible:
- PE, ABS, ASA, PC, PA, PVC – different melting points, unwanted chemical reactions
💡 ReplastMD Recommendation:
Use original PP+FR welding rods and work at a constant temperature of 270–280 °C. Avoid overheating — flame retardant additives can release whitish smoke. Weld slowly with controlled pressure for a smooth joint.
🏭 Manufacturers and trade names
| Manufacturer | Brand / Series | Country / Region |
| LyondellBasell | Hostacom® FR | Germany / Netherlands |
| Borealis | Daplen® FR | Austria |
| SABIC | PP FR Series | Netherlands / Global |
| TotalEnergies | Lumicene® FR | France |
| Hyundai EP | Polytron® FR | South Korea |
| Ravago | Enyglos® FR | EU |
🧠 How to identify PP+FR
- Engraved marking: >PP-FR<
- Flame self-extinguishes after removing the source
- Faint paraffin smell, but without persistent burning
- Density slightly higher than standard PP
- Slow, uniform melting without bubbles
💡 ReplastMD Practical Test: If the part does not support combustion under a flame and has the >PP-FR< marking → confirmed flame retardant PP.