🧩 PP+SRS – Modified Polypropylene (SRS / Automotive TPO)
(Weldable elastic-rigid OEM generation plastic, used in modern car bumpers, spoilers, and bodywork)
🔹 What is PP+SRS
PP+SRS is an advanced polypropylene-based (PP) material modified with thermoplastic elastomers (TPO) and special SRS additives – Scratch Resistant System.
SRS is a surface technology used in modern automotive compounds to provide high scratch resistance, controlled elasticity, and superior UV stability. This type of plastic is used in bumpers that are painted directly without a primer, thanks to its excellent adhesion and glossy appearance after finishing.
🔧 Composition
- PP (Polypropylene) – main structural component
- SRS / TPO (Scratch Resistant System) – elastomeric and anti-scratch phase
- Additives – UV stabilizers, anti-static agents, compatibilizers
- Variants: PP+SRS10, PP+SRS20, PP+TPO-SRS, depending on the elastomer ratio
🚗 Where PP+SRS is used in the automotive industry
| Component | Example parts | Observations |
| Body / Exterior | Bumpers, spoilers, side extensions | Premium OEM material, UV stable |
| Technical Interior | Panels, covers, trims | Anti-scratch surface, matte-glossy |
| Aftermarket / Tuning | Sport parts, diffusers | Weldable, easy to paint and process |
| Color compounds | Mass-colored parts | High abrasion resistance |
🔧 Welding temperatures and methods
| Method | Optimal temperature | Observations |
| Hot air | 270 – 290 °C | Uniform melting without loss of gloss |
| Heat plate (mirror) | 260 – 280 °C | Smooth, clean joint |
| Manual extrusion | 250 – 270 °C | Ideal for long cracks and complex corners |
| Ultrasonic | — | Industrial use only |
🔩 What to weld PP+SRS with (Material compatibility)
The question “what to weld PP+SRS with” is very frequent because SRS has a modified formula compared to standard PP. The material welds effectively with other elastically modified PP or TPO. For perfect adhesion, original PP-SRS or PP-TPO rods are recommended.
✅ Compatible:
- PP+SRS ↔ PP+SRS – ideal combination
- PP+SRS ↔ PP+TPO / PP+EPDM / PP+TPV – excellent compatibility
- PP+SRS ↔ PP-C / PP-H / PP-HI – good compatibility, but more rigid
- PP+SRS ↔ PP-TD / PP-MD20 – partially compatible, different shrinkage
❌ Incompatible:
- PE, ABS, ASA, PC, PA, PVC – different melting points and chemistry
💡 ReplastMD Recommendation:
Use PP-SRS or PP-TPO welding rods at a temperature of 275–285 °C. Clean the whitish oxidation layer, work with constant hot air and medium pressure to avoid excessive glossy marks.
🏭 Manufacturers and trade names
| Manufacturer | Brand / Series | Country / Region |
| LyondellBasell | Hostacom® SRS / TPO-Auto | Germany / Netherlands |
| Borealis | Daplen® SRS | Austria |
| SABIC | PP-TPO-SRS Compound | Netherlands / Global |
| Hyundai EP | Polytron® SRS | South Korea |
| Ravago | Enyglos® TPO-SRS | EU |
🧠 How to identify PP+SRS
- Engraved marking: >PP-SRS<, >PP-TPO-SRS<, or >TPO-Auto<
- Semi-glossy surface with anti-scratch finish
- Yellow-blue flame, faint paraffin smell
- Softens at 275 °C, no bubbles, slow melting
- Density < 1 g/cm³ (partially floats in water)
🛠️ PP+SRS Welding at ReplastMD:
At our service center in Chisinau (Ciocana sector), ReplastMD performs professional PP-SRS welding for:
- OEM bumpers and spoilers with matte-glossy finish
- TPO parts with scratch-resistant coating
- fine aesthetic and structural repairs
- factory-like finish, ready for painting or direct gloss