🧩 PMMA – Polymethyl Methacrylate (Acrylic, Plexiglass)
(Rigid, transparent, and glossy material with excellent optical appearance. Also known as Acrylic, Plexiglass, Altuglas, or Perspex. Intensively used in the automotive industry for headlights, taillights, indicators, and decorative transparent parts.)
🔹 What is PMMA
PMMA (Polymethyl Methacrylate) is a transparent thermoplastic polymer. It features a transparency of up to 92%, high resistance to UV and aging, but has higher mechanical brittleness compared to polycarbonate (PC).
It is a lighter alternative to glass, providing excellent clarity and optical finish. It can be thermoformed, milled, polished, and chemically bonded, but it melts quickly under intense hot air.
🔧 Composition
- Main Monomer: Methyl methacrylate (MMA).
- Density: 1.18–1.20 g/cm³.
- Softening Point: ≈ 100–110 °C.
- Melting Point: ≈ 160–180 °C.
- Chemical Resistance: Good (alcohols, detergents, oils).
- UV Resistance: Excellent (does not yellow in the sun).
- Transparency: 92–93%.
🚗 Where PMMA is used in the automotive industry
| Component | Example parts | Observations |
| Headlights / Taillights | Lenses, diffusers, clear covers | Optical clarity and durable gloss |
| Indicators / Logos | Colored transparent parts, emblems | UV resistance and superior aesthetics |
| Interior / Exterior | Frames, inserts, glossy panels | Premium look, glass-like surface |
| Tech-Optical | Light guides, LED housings | High precision and light transmission |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 220 – 250 °C | Rapid melting, requires strict control |
| Heat Plate (Mirror) | 200 – 230 °C | For flat, clean joints |
| Chemical Bonding | — | Most frequent method (acrylic solvents) |
🔩 What to Weld PMMA With (Material Compatibility)
PMMA is an acrylic material, therefore compatible only with polymers from the same family or blends containing acrylate.
✅ Compatible with:
- PMMA ↔ PMMA / ABS+PMMA / ASA+PMMA / PC+PMMA – good bond.
- PMMA ↔ PC / SAN – partially compatible (with care).
❌ Incompatible with:
- PP, PE, PA, PVC, PS, TPO, simple ABS – cannot be thermally welded.
💡 ReplastMD Recommendation:
For local welding, use PMMA rods at 230–250 °C with slow and uniform heating. For optical or aesthetic joints, chemical bonding with acrylic solvent (e.g., Acryfix, Weld-On) is recommended. Final gloss is achieved through optical polish or controlled hot air.
🏭 Manufacturers and Trade Names
- Röhm / Evonik: Plexiglas®
- Arkema: Altuglas®
- Mitsubishi: Perspex®
- Chi Mei: Acrypet®
🧠 How to Identify PMMA
- Engraved marking: >PMMA<, >ACRYLIC<, >PLEXIGLAS<.
- Very transparent material, rigid, with a glass-like gloss.
- Yellow-blue flame, specific sweet acrylic scent.
- Softens quickly when heated, melts cleanly without bubbles.
- ReplastMD practical test: if the part is completely transparent, rigid, scratches easily but doesn’t yellow under UV, it’s confirmed PMMA (acrylic).
🛠️ PMMA Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PMMA welding and bonding for taillight lenses and decorative frames, ensuring an invisible joint and perfect optical gloss.