🧩 PE-HD+FR – Flame Retardant High-Density Polyethylene
(Weldable, chemically and thermally resistant plastic, used in automotive electrical housings and systems)
🔹 What is PE-HD+FR
PE-HD+FR (High Density Polyethylene – Flame Retardant) is a high-density polyethylene modified with flame-retardant additives. It is used where fire resistance and chemical stability are required. It is a semi-crystalline plastic with low weight and good mechanical strength, but low thermal adhesion to materials outside the PE family.
🔧 Composition
- High-Density Polyethylene (PE-HD) – polyolefin base.
- FR Additives (Flame Retardant) – brominated, phosphoric, or mineral-based.
- UV Stabilizers / Antioxidants – optional for aging protection.
🚗 Where PE-HD+FR is used in the automotive industry
| Component | Example parts | Observations |
| Electrical Protection | Fuse boxes, battery covers, ECU housings | Requires fire-retardant behavior |
| Interior / Technical | Ventilation housings, acoustic panels | Resistant to moderate temperatures |
| Auxiliary Equipment | Sensor housings, wiring brackets | Easy to mold, but difficult to glue |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 260 – 280 °C | Requires a wide nozzle and careful flame control |
| Heat Plate (Mirror) | 250 – 270 °C | Used for thick plates |
| Manual Extrusion | 240 – 260 °C | For long cracks and rigid edges |
🔩 What to Weld PE-HD+FR With (Material Compatibility)
The main rule is: weld only with PE-HD or PE-HD+FR of the same type. Polyethylene has low surface energy and does not form chemical bonds outside the PE family.
✅ Compatible:
- PE-HD ↔ PE-HD – secure and durable joint, requires a clean surface.
- PE-HD ↔ PE-HD+FR – partially compatible; flame-retardant zones may melt slower.
❌ Incompatible:
- PP (Polypropylene) – different melting point, bonding impossible.
- ABS, ASA, PC, PA – will not adhere; reacts differently to heat.
- PVC – releases toxic gases, carbonizes.
💡 ReplastMD Recommendation:
For a proper weld, clean the outer oxidized layer before welding and use original PE-HD welding rods. For PE-HD+FR variants, adjust the temperature by +10…+15 °C above standard values, as flame-retardant additives reduce fluidity.
🏭 Manufacturers and Trade Names
- LyondellBasell: Hostalen® FR
- Borealis: BorSafe® FR
- Sabic: Vestolen® FR
- TotalEnergies: Lumicene® HDPE FR
🧠 How to Identify PE-HD+FR
- Engraved marking: >PE-HD< or >HDPE< (optionally “FR”).
- Pale yellow flame, faint paraffin smell.
- Floats in water (density < 1 g/cm³).
- Melts uniformly when heated, without heavy smoke.
🛠️ PE-HD+FR Welding at ReplastMD:
At our service center in Chisinau (Ciocana sector), ReplastMD performs professional PE-HD welding, including flame-retardant variants, for:
- electrical boxes, sensor housings, and protective covers;
- liquid tanks or PE-HD technical structures;
- repairing and reinforcing long cracks;
- reconstituting missing parts with original PE-HD rods.