🧩 PP-R – Polypropylene Random Copolymer
(Weldable plastic with optimal thermal resistance and flexibility, used in automotive and technical applications)
🔹 What is PP-R
PP-R (Polypropylene Random Copolymer) is a random blend of propylene and ethylene, designed to combine the thermal resistance of PP-H with the elasticity of PP-C.
It exhibits stable behavior under temperature variations and excellent stress-crack resistance, making it ideal for automotive parts, pipes, and technical components.
🔧 Composition
- PP (Polypropylene) – main component
- Ethylene (3–7%) – adds flexibility and clarity
- Additives – UV stabilizers, antioxidants, colorants
- Can be modified with talc or glass fiber for additional rigidity
🚗 Where PP-R is used in the automotive industry
| Component | Example parts | Observations |
| Bodywork | Bumpers, covers, light brackets | Elastic, impact-resistant |
| Interior | Dashboard elements, covers, consoles | Matte finish, malleable |
| Technical / Systems | Ventilation parts, connectors, fluid pipes | Withstands high temperatures |
| Aftermarket / DIY | Custom parts, casings, mudguards | Easy to weld, clean look |
🔧 Welding temperatures and methods
| Method | Optimal temperature | Observations |
| Hot air | 260 – 280 °C | Uniform and clean weld |
| Heat plate (mirror) | 250 – 270 °C | Ideal for flat joints |
| Manual extrusion | 240 – 260 °C | For long cracks |
| Electrofusion | — | For industrial PP-R applications only |
🔩 What to weld PP-R with (Material compatibility)
The question “what to weld PP-R with” is common — this material behaves almost identically to PP-C, being compatible with all forms of PP but more thermally stable.
✅ Compatible:
- PP-R ↔ PP-R – perfect bond, uniform and elastic
- PP-R ↔ PP-C / PP-H – fully compatible, similar melting
- PP-R ↔ PP-TD / PP-GF – partially compatible (watch for shrinkage)
- PP-R ↔ PE-HD – low compatibility
❌ Incompatible:
- ABS, ASA, PC, PA, PVC – will not adhere, different temperatures
- PA6, PET, PBT – react differently to melting
💡 ReplastMD Recommendation:
Use PP-R or PP-C welding rods at 270–280 °C for optimal results.
Clean the oxidation surface and do not overheat — the material becomes brittle above 290 °C.
🏭 Manufacturers and trade names
| Manufacturer | Brand / Series | Country / Region |
| LyondellBasell | Moplen® RP | Germany / Netherlands |
| Borealis | Daplen® RP | Austria |
| SABIC | PP Random Copolymer | Netherlands / Global |
| TotalEnergies | Lumicene® RP | France |
| Repsol | Isplen® RP | Spain |
| Hyundai EP | Polytron® RP | South Korea |
🧠 How to identify PP-R
- Engraved marking: >PP-R<
- Yellow-blue flame, smells like paraffin
- Floats in water (density < 1 g/cm³)
- Softens at 270 °C
- Softer texture than PP-H, but more rigid than PP-C
💡 ReplastMD Practical Test: If the material bends easily but returns to shape without cracking, melting cleanly at 270 °C → it is PP-R.