🧩 COC+PP – Cyclic Olefin Copolymer + Polypropylene
(Semi-transparent and weldable technical material, combining COC clarity and rigidity with PP thermal resistance and processability. Used in automotive covers, housings, and optical parts.)
🔹 What is COC+PP
COC+PP is a technical olefinic blend that combines COC (Cyclic Olefin Copolymer) – a rigid and transparent polymer – with polypropylene (PP), which provides thermal stability, flexibility, and cost-efficiency.
The result is a rigid, lightweight, dimensionally stable, and semi-transparent material, ideal for automotive parts with mixed aesthetic and mechanical requirements. It is frequently used in optical housings, decorative covers, sensors, headlights, and transparent supports.
🔧 Composition
- COC (Cyclic Olefin Copolymer) – 30–60 %
- PP (Polypropylene) – 40–70 %
- Additives – compatibilizers, UV stabilizers, antioxidants, optical pigment.
- Density: ≈ 0.98–1.03 g/cm³.
- Melting Point: ≈ 165–175 °C.
- Clarity: semi-transparent, high gloss.
🚗 Where COC+PP is used in the automotive industry
| Component | Example parts | Observations |
| Auto Optics | Sensor covers, lenses, diffusers | Balanced clarity and rigidity |
| Technical Housings | Electronic supports, motor covers | Thermal stability and UV resistance |
| Decorative Interior | Panels, inserts, glossy covers | High gloss, aesthetic finish |
| Industrial / Aftermarket | Lightweight housings, optical elements | Easy to process and thermally weldable |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 260 – 280 °C | Clean weld, uniform melting |
| Heat Plate (Mirror) | 250 – 270 °C | Recommended for flat and aesthetic joints |
| Laser / Ultrasonic | — | Ideal for optical and aesthetic applications |
🔩 What to Weld COC+PP With (Material Compatibility)
Being olefinic, the material is compatible with PP, COC, and TPO or TPV blends.
✅ Compatible:
- COC+PP ↔ COC+PP – ideal combination.
- COC+PP ↔ COC / PP / TPO / TPV – good compatibility.
- COC+PP ↔ PP+EPDM / PP+PE – partial compatibility (superficial bonding).
❌ Incompatible:
- ABS, ASA, PC, PA, PVC – polar materials, uneven melting.
💡 ReplastMD Recommendation:
Use PP or COC rods at a temperature of 270–280 °C. Heat uniformly without overheating (the material may turn opaque/matte). For visible parts, mirror (heat plate) welding is recommended for an aesthetic, glossy joint.
🏭 Manufacturers and Trade Names
- TOPAS Advanced Polymers: TOPAS® Blend PP
- Zeon Chemicals: Zeonor® PP Compound
- Mitsui Chemicals: Apel™ PP/COC
- SABIC: COC-PP Alloy
- Borealis: Daplen® COC+PP
🧠 How to Identify COC+PP
- Engraved marking: >COC+PP<, >PP/COC<, >COC-PP<, >TOPAS-PP<.
- Glossy, rigid, semi-transparent surface.
- Yellow-blue flame, faint paraffin smell.
- Softens uniformly at ≈ 270 °C, without bubbles.
- Feels colder and denser than simple PP.
🛠️ COC+PP Welding at ReplastMD:
At our service center in Chisinau (Ciocana sector), ReplastMD performs professional COC+PP welding for:
- covers, supports, and semi-transparent optical parts;
- precision aesthetic and technical restoration;
- reconstructing mounts and cracked areas;
- clear, glossy finish with invisible joints.