🧩 PMMA-HI – High Impact Polymethyl Methacrylate
(Acrylic material improved with elastomers for superior impact resistance. It maintains the transparency and gloss of standard PMMA but becomes much more durable and resistant to cracks. Ideal for headlights, taillights, and optical elements.)
🔹 What is PMMA-HI
PMMA-HI (High Impact Polymethyl Methacrylate) is a modified acrylic made by adding elastomers (acrylic rubbers, MBS, or styrenic rubbers) to its molecular structure.
These modifications reduce the classic brittleness of PMMA, offering elasticity and resistance to mechanical shocks without compromising transparency. The result is a clear, durable, glossy, and UV-stable material — widely used in the automotive industry for lenses and covers exposed to vibrations and thermal shifts.
🔧 Composition
- PMMA (Polymethyl Methacrylate): 85–95 %
- Acrylic Elastomers / MBS: 5–15 %
- UV / Thermal Additives: 1–2 %
- Density: 1.15–1.19 g/cm³
- Melting Point: ≈ 170–190 °C
- UV Resistance: Excellent.
- Impact Resistance: 5–8 times higher than standard PMMA.
🚗 Where PMMA-HI is used in the automotive industry
| Component | Example parts | Observations |
| Headlights / Taillights | Lenses, diffusers, clear covers | Transparency + crack resistance |
| Indicators / Logos | Colored transparent parts | Superior UV resistance |
| Decorative Int / Ext | Glossy frames, inserts | Quality optical finish |
| Tech-Optical | Sensor covers, light guides | Thermal stability and clarity |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 230 – 250 °C | Controlled melting, no bubbles |
| Heat Plate (Mirror) | 210 – 230 °C | Clean joint without loss of clarity |
| Chemical Bonding | — | Recommended for aesthetic finishes (acrylic solvent) |
🔩 What to Weld PMMA-HI With (Material Compatibility)
PMMA-HI has good compatibility with acrylic materials and blends containing PMMA or SAN.
✅ Compatible with:
- PMMA-HI ↔ PMMA / ABS+PMMA / ASA+PMMA / PC+PMMA / SAN – ideal.
- PMMA-HI ↔ Transparent PMMA – full compatibility.
❌ Incompatible with:
- PP, PE, PA, PVC, PS, simple ABS, TPO – no thermal adhesion.
💡 ReplastMD Recommendation:
Use PMMA-HI or standard PMMA rods at 240–250 °C. Heat gradually; overheating can produce optical bubbles. For clear finishes, chemical bonding with acrylic solvent (e.g., Acryfix, Weld-On 4) is recommended.
🏭 Manufacturers and Trade Names
- Röhm / Evonik: Plexiglas® Resist / Impact
- Arkema: Altuglas® Impact / ShieldUp
- Mitsubishi: Acrylite® Impact / Perspex® HI
- Chi Mei: Acrypet® HI / Impact
🧠 How to Identify PMMA-HI
- Engraved marking: >PMMA-HI<, >IMPACT PMMA<, >PLEXIGLAS RESIST<.
- Very glossy surface, rigid but slightly elastic.
- Yellow-blue flame, specific sweet acrylic scent.
- Softens at ≈ 230 °C without bubbling.
- ReplastMD practical test: if the part is transparent, glossy, slightly elastic, and marked >PMMA-HI<, it’s a confirmed impact-modified acrylic.
🛠️ PMMA-HI Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PMMA-HI welding and bonding for lenses and decorative elements, ensuring a clear, crack-free, and perfect optical gloss finish.