PMMA-FR LS-FR
Flame-retardant grade
GB GB/T 7134-2008 Type 4
LS-FR = low-smoke FR
Use when smoke density and toxicity limits (EN 45545 HL2, GB/T 8627) govern, not just ignition resistance.
Values for the LS-FR condition
Other PMMA-FR grades and fills
PMMA-FR is listed in 8 conditions; see the grade overview at PMMA-FR.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Impact-modified FR | For FR glazing and covers that must survive handling/impact; trades stiffness, hardness and heat resistance for 2–4× notched impact. | — | 45 | 25 | 60 HRM |
LS-FRThis page Low-smoke FR | Use when smoke density and toxicity limits (EN 45545 HL2, GB/T 8627) govern, not just ignition resistance. | 54 | 56 | 3 | 88 Shore D |
UL 94 V-0 grade | Pick when a V-0 listing at 1.5–3 mm is mandatory (electrical enclosures, rail interiors); accept lower clarity and toughness. | — | 55 | 3 | — |
Extruded FR sheet | Lower-cost FR sheet with tighter thickness tolerance and easier thermoforming/solvent bonding; slightly lower heat and solvent resistance than cast. | 58 | 60 | 4.5 | 86 Shore D |
Halogen-free FR | Choose for RoHS/REACH-sensitive rail, marine and electronics parts where halogenated FR and corrosive smoke are prohibited. | 58 | 60 | 3.5 | 87 Shore D |
UV-stabilized FR | Adds HALS/UV absorbers to offset yellowing of the FR package for exterior signage, canopies and skylights. | 61 | 64 | 4 | 88 Shore D |
UL 94 V-2 grade | Standard commercial FR acrylic where B1 / V-2 is sufficient and transparency must stay near virgin PMMA. | 63 | 66 | 4 | 88 Shore D |
CAST-FRDefault Cast FR sheet | Default choice for architectural glazing, partitions and signage that must pass B1 / UL 94 V-2 fire tests with high clarity. | — | 68 | 4.5 | — |
What is PMMA-FR LS-FR?
PMMA-FR LS-FR is PMMA-FR in the LS-FR grade — use when smoke density and toxicity limits (EN 45545 HL2, GB/T 8627) govern, not just ignition resistance. PMMA-FR LS-FR has a yield strength of 54 MPa (7.83 ksi) and a tensile strength of 56 MPa (8.12 ksi) — stronger than 60% of polymer grades. Elongation at break is 3% and the elastic modulus is 3.4 GPa (0.493 Msi). PMMA-FR LS-FR has a density of 1.26 g/cm³ (0.0455 lb/in³), heavier than 66% of polymer grades. Its glass-transition temperature is 103°C (217 °F). CAST-FR is the default condition FabDigit quotes; LS-FR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 95/100, better than 98% of polymer grades
- Good UV / weathering resistance — 80/100, better than 86% of polymer grades
- Low, predictable mold shrinkage — 0.35%, better than 86% of polymer grades
- Stiff — 3.4 GPa (0.493 Msi), better than 82% of polymer grades
Limitations
- Low fracture toughness — 0.95 MPa·√m (0.865 ksi·√in), worse than 89% of polymer grades
- Limited ductility — 3%, worse than 83% of polymer grades
- Limited service temperature — 72°C (162 °F), worse than 75% of polymer grades
PMMA-FR LS-FR properties
Typical room-temperature values for PMMA-FR LS-FR; 29 are specific to this condition. Other listed values are PMMA-FR reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
PMMA-FR LS-FR has a density of 1.26 g/cm³ (0.0455 lb/in³), heavier than 66% of polymer grades. Its glass-transition temperature is 103°C (217 °F).
Mechanical16
PMMA-FR LS-FR has a yield strength of 54 MPa (7.83 ksi) and a tensile strength of 56 MPa (8.12 ksi) — stronger than 60% of polymer grades. Elongation at break is 3% and the elastic modulus is 3.4 GPa (0.493 Msi).
Thermal11
PMMA-FR LS-FR is rated for continuous service to 72°C (162 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 72 µm/m·K (40 µin/in·°F).
Electrical7
PMMA-FR LS-FR is an electrical insulator with a dielectric strength of 25 kV/mm (635 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (78/100), worse than 61% of polymer grades. UV resistance is very good.
Sustainability4
Producing a kilogram of PMMA-FR LS-FR takes about 105 MJ of energy and emits 6.6 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PMMA-FR LS-FR's machinability is very good (70/100, better than 74% of polymer grades); weldability fair (45/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PMMA-FR LS-FR
Is PMMA-FR easy to machine?
Machines and laser-cuts cleanly with sharp positive-rake tools, high speed and low feed; anneal at 75–80 °C before and after machining to avoid crazing, and avoid coolants containing alcohols.
Can PMMA-FR be welded?
Not fusion-welded in practice — join by solvent cementing (methylene chloride/MMA syrup) or acrylic structural adhesives; hot-gas and ultrasonic welding possible but give lower-strength joints.
Can PMMA-FR be formed, bent or molded?
Thermoform sheet at 140–160 °C after drying 2–4 h at 80 °C; injection mold at 210–245 °C melt / 55–85 °C mold and keep residence time short so the flame retardant does not decompose and discolor.
What surface finishes work on PMMA-FR?
Flame- or diamond-polish edges for optical clarity; can be screen-printed, hard-coated for abrasion resistance or vacuum-metallized — avoid solvent-based cleaners that craze the surface.
PMMA-FR chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| flame retardant (organophosphate ester /type determines halogen-free vs halogenated variant | 4 – 18 | 10 |
| antimony trioxide (synergist, halogenateomitted in halogen-free grades | 0 – 3 | 1 |
| impact modifier (acrylic core-shell rubbimpact-modified variants only | 0 – 15 | 0 |
| UV absorber / HALS, processing aids | 0.1 – 1 | 0.4 |
| poly(methyl methacrylate) (MMA units)base resin; cast grades may include small methyl acrylate comonomer | ≥ 80 (balance) | — |
PMMA-FR LS-FR — frequently asked
What is PMMA-FR LS-FR used for?
PMMA-FR LS-FR is typically used for rail vehicle glazing, building interior panels, fire-rated signage and public transit windows. In short: fire-rated acrylic sheet; V-0 and low-smoke options; narrow processing window.
What is the yield strength of PMMA-FR LS-FR?
PMMA-FR LS-FR has a typical yield strength of 54 MPa (7.83 ksi) and a tensile strength of 56 MPa (8.12 ksi) — stronger than 60% of polymer grades. Strength varies by condition: see the 8 listed tempers.
Is PMMA-FR LS-FR easy to machine?
Yes — machinability is rated very good (70/100, better than 74% of polymer grades). Machines and laser-cuts cleanly with sharp positive-rake tools, high speed and low feed; anneal at 75–80 °C before and after machining to avoid crazing, and avoid coolants containing alcohols.
Can PMMA-FR LS-FR be welded?
With care — weldability is rated fair (45/100). Not fusion-welded in practice — join by solvent cementing (methylene chloride/MMA syrup) or acrylic structural adhesives; hot-gas and ultrasonic welding possible but give lower-strength joints.
What surface finishes work on PMMA-FR LS-FR?
Flame- or diamond-polish edges for optical clarity; can be screen-printed, hard-coated for abrasion resistance or vacuum-metallized — avoid solvent-based cleaners that craze the surface.
Can PMMA-FR LS-FR be formed, bent or molded?
Thermoform sheet at 140–160 °C after drying 2–4 h at 80 °C; injection mold at 210–245 °C melt / 55–85 °C mold and keep residence time short so the flame retardant does not decompose and discolor.
What is the maximum service temperature of PMMA-FR LS-FR?
PMMA-FR LS-FR is rated for continuous use to about 72°C (162 °F), and briefly to 95°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between PMMA-FR CAST-FR and PMMA-FR V2?
CAST-FR is the default condition — default choice for architectural glazing, partitions and signage that must pass B1 / UL 94 V-2 fire tests with high clarity. V2: standard commercial FR acrylic where B1 / V-2 is sufficient and transparency must stay near virgin PMMA. Yield strength is 54 MPa in CAST-FR versus 63 MPa in V2.
Sources
- UL 94 Tests for Flammability of Plastic Materials — UL Solutions (2021)
- ISO 4589-2 Determination of burning behaviour by oxygen index — ISO (2017)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- CAMPUS plastics datasheets — PMMA (ISO 10350 property set) — CWFG (2024)
- Cast and extruded flame-retardant acrylic sheet technical data — Röhm / Mitsubishi Chemical / Chinese sheet producers (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.