🧩 PP+MD – Mineral Filled Polypropylene
(Rigid and stable weldable plastic, used in structural parts and technical automotive elements)
🔹 What is PP+MD
PP+MD is a polypropylene modified with mineral filler (usually calcium carbonate, chalk, or dolomite), designed for parts requiring dimensional stability, thermal resistance, and low production costs.
It offers superior rigidity compared to plain PP while maintaining good processability and weldability.
🔧 Composition
- PP (Polypropylene) – base matrix
- MD (Mineral Filler 10–40%) – mineral powders: CaCO₃, talc, dolomite
- Additives – UV stabilizers, antioxidants, colorants
- Common variants: PP+MD10, PP+MD20, PP+MD40
🚗 Where PP+MD is used in the automotive industry
| Component | Example parts | Observations |
| Body / Exterior | Covers, grilles, trims | Rigid, resistant to moderate shocks |
| Technical Interior | Panels, covers, supports | Stable under temperature variations |
| Engine Compartment | Mounts, technical casings | Rigid, stands up to vibrations |
| Other Applications | Industrial casings, fastening parts | Easy to weld and finish |
🔧 Welding temperatures and methods
| Method | Optimal temperature | Observations |
| Hot air | 270 – 290 °C | Recommended for most parts |
| Heat plate (mirror) | 260 – 280 °C | For flat and clean joints |
| Manual extrusion | 250 – 270 °C | For technical repairs and corners |
| Ultrasonic | — | Industrial use only |
🔩 What to weld PP+MD with (Material compatibility)
The question “what to weld PP+MD with” often arises in service shops.
As the material is PP-based, it can be welded with other types of polypropylene, preferably with similar fillers (mineral or talc-filled).
✅ Compatible:
- PP+MD ↔ PP+MD – ideal combination, stable weld
- PP+MD ↔ PP-TD / PP-H / PP-C – good compatibility
- PP+MD ↔ PP-GF20 – partially compatible, different rigidity
- PP+MD ↔ PP+MD20 / PP+MD30 – full compatibility
❌ Incompatible:
- PE, ABS, ASA, PC, PA, PVC – will not adhere; different chemistry
💡 ReplastMD Recommendation:
Use original PP-MD or PP-C welding rods at 275–285 °C.
Clean the surface of any visible mineral impurities and maintain uniform melting for a smooth and strong weld.
🏭 Manufacturers and trade names
| Manufacturer | Brand / Series | Country / Region |
| LyondellBasell | Hostacom® MD Series | Germany / Netherlands |
| Borealis | Daplen® MD | Austria |
| SABIC | PP Mineral Filled | Netherlands / Global |
| TotalEnergies | Lumicene® MD | France |
| Hyundai EP | Polytron® MD | South Korea |
| Ravago | Enyglos® MD | EU |
🧠 How to identify PP+MD
- Engraved marking: >PP-MD< or >PP-Mineral<
- Yellow-blue flame, smells like paraffin
- Melts at 270 °C
- Density slightly above 1 g/cm³ (sinks slowly in water)
- Matte, fine appearance with a uniform texture
💡 ReplastMD Practical Test: If the part is rigid, slightly heavier than plain PP, and has the >PP-MD< marking → it is PP+MD.