What is Exolon FR?
Exolon® FR – flame-retardant solid polycarbonate sheet (PC), UL 94 V-0 / EN 45545-2 / FAR 25.853, extremely impact-resistant
Technical data
| Property | Value | Test method |
|---|---|---|
| Physical Properties | ||
| Density | 1200 kg/m³ | ISO 1183-1 |
| Water absorption (saturation, water 23 °C) | 0.3 % | ISO 62 |
| Water absorption (23 °C, 50 % r.h.) | 0.12 % | ISO 62 |
| Refractive index (method A) | 1.587 | ISO 489 |
| clear 099 (3 mm) | 88 % | DIN 5036 |
| clear 099 (5 mm) | 85 % | DIN 5036 |
| DX white 139 (3 mm) | 53 % | DIN 5036 |
| Mechanical Properties | ||
| Modulus of elasticity (1 mm/min) | 2400 MPa | ISO 527-1, -2 |
| Yield stress (50 mm/min) | >60 MPa | ISO 527-1, -2 |
| Yield strain (50 mm/min) | 6 % | ISO 527-1, -2 |
| Nominal strain at break (50 mm/min) | >50 % | ISO 527-1, -2 |
| Flexural modulus (2 mm/min) | 2400 MPa | ISO 178 |
| Flexural strength (2 mm/min) | >90 MPa | ISO 178 |
| Charpy impact strength (23 °C, unnotched) | no break kJ/m² | ISO 179-1eU |
| Charpy impact strength (23 °C, 3 mm, notched) | 70P kJ/m² | ISO 179-1eU |
| Izod impact strength (23 °C, 3.2 mm, notched) | 60P kJ/m² | ISO 180-A |
| Thermal Properties | ||
| Vicat softening temperature (50 N; 50 °C/h) | 146 °C | ISO 306 |
| Heat deflection temperature (1.8 MPa) | 127 °C | ISO 75-1, -2 |
| Heat deflection temperature (0.45 MPa) | 139 °C | ISO 75-1, -2 |
| Continuous service temperature (no load) | ~ 120 °C | |
| Temperature range | -100 bis +120 °C | |
| Coefficient of thermal expansion (23–55 °C) | 0.70 10^-4/K | ISO 11359-1, -2 |
| Thermal conductivity (23 °C) | 0.2 W/(m·K) | ISO 8302 |
| Electrical Properties | ||
| Dielectric strength (1 mm) | 34 kV/mm | IEC 60243-1 |
| Volume resistivity | 10^14 Ω·m | IEC 60093 |
| Surface resistivity | 10¹⁶ Ω | IEC 60093 |
| Dielectric constant (100 Hz) | 3.1 | IEC 60250 |
| Dielectric constant (1 MHz) | 3 | IEC 60250 |
| Dissipation factor (100 Hz) | 10 10^-4 | IEC 60250 |
| Dissipation factor (1 MHz) | 90 10^-4 | IEC 60250 |
| UL 94 (≥ 2.0 mm) | V-0 | UL 94 |
| EN 45545-2 (rail vehicles) | R1/HL1, R3/HL2, R4/HL3, R22–R24/HL3 | EN 45545-2 |
| Aviation | Part 1 (a)(1)(i)/(ii) | FAR 25.853 |
Exolon FR in detail
1What is Exolon FR?+
Exolon® FR consists of polycarbonate, an amorphous engineering thermoplastic with no defined melting point that softens above the glass transition temperature (around 147 °C). Compared with standard PC, the FR grade is flame-retardant and thus reaches significantly higher fire classes. Its hallmark remains the extreme toughness: in the unnotched Charpy test the material does not break ("no break"), and it stays impact-resistant even at low temperatures. The clear 099 grade is highly transparent; DX white 139 is a diffuser sheet for lighting.
2How does Liedtke machine Exolon FR?+
Exolon® FR machines well – milling, turning, drilling and sawing produce clean, dimensionally accurate results; the DX grade can also be thermoformed and cold-bent. Before thermoforming we pre-dry the sheets because of hygroscopy; after machining, annealing can relieve internal stresses. Because of the stress-cracking sensitivity we avoid solvent-based cutting fluids. This is how we reliably produce impact-resistant, fire-safety precision and protective parts – from single pieces to series production.
3When should I choose Exolon FR?+
Exolon® FR is worthwhile whenever transparency and impact resistance must be combined with high fire protection – for example:
- Lighting fixtures and covers on rail vehicles (EN 45545-2)
- Electrical components and protective guards with UL 94 V-0
- Fire-safety transparent parts and viewing windows
- Aviation applications (FAR 25.853)
- Diffuser and light-guiding sheets (DX white 139)
4What determines the price of a Exolon FR part?+
Exolon® FR is a flame-retardant specialty sheet and is priced above standard polycarbonate (GP) and well above acrylic (PMMA). The part price is mainly determined by grade (clear/UV/DX), sheet thickness and dimension, material utilisation (offcut), machining effort and lot size. We are happy to quote binding prices on request based on your drawing.
5When is Exolon FR not the right choice?+
Equally important are the limits of the material:
- Food contact – Exolon® FR is a flame-retardant grade, not intended for this
- Contact with solvents, alkalis or hydrocarbons (risk of stress cracking)
- Permanent outdoor use only with the UV grade (UV clear 2099)
- Scratch- and abrasion-loaded surfaces – PC is soft (hard-coat if needed)
- When only highest optical clarity without fire protection matters – then PMMA or standard PC
6Advantages and disadvantages of Exolon FR+
An honest assessment – and how the disadvantages can be mitigated in practice: Advantages:
Disadvantages:
Practical tip: Exolon® FR is the right choice when transparent, impact-resistant parts must also meet high fire-protection requirements – for example in rail vehicles, lighting and electrical engineering. If only impact resistance without fire protection matters, Exolon® GP (standard PC) is more economical; for highest scratch resistance and weathering, acrylic (PMMA) is the better choice.
- Excellent fire protection (UL 94 V-0, EN 45545-2, FAR 25.853)
- Extremely high impact strength – virtually unbreakable, even in cold
- Wide temperature range (-100 … +120 °C)
- High optical clarity (grade clear 099)
- Good machinability, thermoformable and cold-bendable (DX)
- Not intended for food contact (flame-retardant grade)
- Soft, scratch-sensitive surface (without hard coating)
- Sensitive to solvents/alkalis (stress cracking)
- Outdoor use only with UV grade (UV clear 2099)
- Higher price than standard PC and PMMA
Typical properties
- Excellent fire classification (UL 94 V-0, EN 45545-2, FAR 25.853)
- Extremely high impact strength (Charpy unnotched: no break)
- Wide temperature range (-100 … +120 °C)
- High heat deflection temperature (continuous use ~ 120 °C)
- High optical clarity (grade clear 099)
- Good electrical insulator
- Easy to thermoform, cold-bend and machine (DX grade)
- Grades: clear 099, UV clear 2099 (outdoor), DX white 139 (diffuser)
Typical industries
- Rail vehicle and railway industry (EN 45545-2)
- Lighting technology
- Electrical engineering and electronics
- Aerospace (FAR 25.853)
- Mechanical and plant engineering (protective guards)
- Safety and fire-protection technology
Downloads for Exolon FR
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