XXX FR-2
Flame-retardant grade
ASTM D709 Grade XXX, D709 Type XXX · GB 3025
FR-2 = flame-retardant paper-phenolic
Flame-retardant version of the punchable paper-phenolic family, the classic single-sided copper-clad PCB substrate; use where UL 94V-0 is required.
Values for the FR-2 condition
Other XXX grades and fills
XXX is listed in 4 conditions; see the grade overview at XXX.
Compare all 4 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Cold-punchable high-electrical paper-phenolic | Choose when thin parts must be punched at room temperature without pre-heat; slightly lower stiffness and higher moisture pickup than XXX. | — | 95 | 1.6 | 95 HRM |
Hot-punchable high-electrical paper-phenolic | Same electrical class as XXX but formulated to punch cleanly when pre-heated (~90–130 °C); use for stamped washers and terminal strips. | — | 100 | 1.5 | 100 HRM |
FR-2This page Flame-retardant paper-phenolic | Flame-retardant version of the punchable paper-phenolic family, the classic single-sided copper-clad PCB substrate; use where UL 94V-0 is required. | — | 100 | 1.4 | 100 HRM |
XXXDefault Standard high-electrical paper-phenolic laminate | Pick for the best moisture and 1 MHz loss performance in the paper-base series where parts are machined, not punched. | — | 110 | 1.3 | 105 HRM |
What is XXX FR-2?
XXX FR-2 is XXX in the FR-2 grade — flame-retardant version of the punchable paper-phenolic family, the classic single-sided copper-clad PCB substrate; use where UL 94V-0 is required. XXX FR-2 has a tensile strength of 100 MPa (14.5 ksi), weaker than 67% of composite grades. Elongation at break is 1.4% and the elastic modulus is 7.5 GPa (1.09 Msi). XXX FR-2 has a density of 1.36 g/cm³ (0.0491 lb/in³), lighter than 70% of composite grades. XXX is the default condition FabDigit quotes; FR-2 is available on request or by drawing note.
Advantages
- Low embodied carbon — 4.5 kg CO₂/kg, better than 79% of composite grades
- Easy to machine — 62/100, better than 75% of composite grades
Limitations
- Low fracture toughness — 1.6 MPa·√m (1.46 ksi·√in), worse than 95% of composite grades
- Limited service temperature — 105°C (221 °F), worse than 90% of composite grades
- Needs corrosion protection — 58/100, worse than 83% of composite grades
- Poor heat conductor — 0.25 W/m·K (0.144 BTU/hr·ft·°F), worse than 76% of composite grades
- Hard to polish — 25/100, worse than 76% of composite grades
XXX FR-2 properties
Typical room-temperature values for XXX FR-2; 20 are specific to this condition. Other listed values are XXX reference data and may not represent this condition. Bars are the position among composite grades.
Physical3
XXX FR-2 has a density of 1.36 g/cm³ (0.0491 lb/in³), lighter than 70% of composite grades.
Mechanical13
XXX FR-2 has a tensile strength of 100 MPa (14.5 ksi), weaker than 67% of composite grades. Elongation at break is 1.4% and the elastic modulus is 7.5 GPa (1.09 Msi).
Thermal8
XXX FR-2 is rated for continuous service to 105°C (221 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), worse than 76% of composite grades. Thermal expansion is 22 µm/m·K (12.2 µin/in·°F).
Electrical7
XXX FR-2 is an electrical insulator with a dielectric strength of 15 kV/mm (381 V/mil) and a resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 83% of composite grades. UV resistance is poor.
Sustainability3
Producing a kilogram of XXX FR-2 takes about 95 MJ of energy and emits 4.5 kg of CO₂ — less than 72% of composite grades. Typical recycled content is 0%.
Manufacturability2
XXX FR-2's machinability is good (62/100, better than 75% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with XXX FR-2
Is XXX easy to machine?
Saws, drills and mills readily with sharp carbide tooling and high speed/low feed; dust is abrasive and irritating so use extraction, and back up thin sheet to avoid edge delamination.
Can XXX be welded?
Thermoset — cannot be welded; join by mechanical fasteners or epoxy/phenolic adhesives after abrading and degreasing the surface.
Can XXX be formed, bent or molded?
Supplied as fully cured flat sheet, rod or tube — no post-forming; standard XXX must be machined, while XXXP (hot punch, part pre-heated ~90–130 °C) or XXXPC (cold punch) are chosen for stamped parts.
What surface finishes work on XXX?
Edges should be sealed with varnish or epoxy to keep moisture out and preserve insulation resistance; can be painted after light abrasion, and no plating or anodizing applies.
XXX 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 |
|---|---|---|
| phenol-formaldehyde resinresole/novolac phenolic binder, may contain plasticiser and moisture-resist additives | 40 – 55 | 48 |
| residual volatiles / moisture | 0 – 1.5 | 0.5 |
| bleached cellulose kraft insulating papealpha-cellulose electrical grade paper webs | ≥ 45 (balance) | — |
XXX FR-2 — frequently asked
What is XXX FR-2 used for?
XXX FR-2 is typically used for high-grade electrical insulation boards, transformer components and terminal insulation. In short: highest insulation resistance, paper-base; machining grade, not punchable; low-cost electrical laminate.
What is the tensile strength of XXX FR-2?
XXX FR-2 has a typical tensile strength of 100 MPa (14.5 ksi) — weaker than 67% of composite grades. Strength varies by condition: see the 4 listed tempers.
Is XXX FR-2 easy to machine?
Reasonably — machinability is rated good (62/100, better than 75% of composite grades). Saws, drills and mills readily with sharp carbide tooling and high speed/low feed; dust is abrasive and irritating so use extraction, and back up thin sheet to avoid edge delamination.
Can XXX FR-2 be welded?
Thermoset — cannot be welded; join by mechanical fasteners or epoxy/phenolic adhesives after abrading and degreasing the surface.
What surface finishes work on XXX FR-2?
Edges should be sealed with varnish or epoxy to keep moisture out and preserve insulation resistance; can be painted after light abrasion, and no plating or anodizing applies.
Can XXX FR-2 be formed, bent or molded?
Supplied as fully cured flat sheet, rod or tube — no post-forming; standard XXX must be machined, while XXXP (hot punch, part pre-heated ~90–130 °C) or XXXPC (cold punch) are chosen for stamped parts.
What is the maximum service temperature of XXX FR-2?
XXX FR-2 is rated for continuous use to about 105°C (221 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D709 — Standard Specification for Laminated Thermosetting Materials — ASTM International (2017)
- NEMA LI 1 — Industrial Laminated Thermosetting Products — NEMA (1998)
- IEC 60893-3-4 — Insulating materials, rigid laminated sheets, cellulose paper/phenolic (PF CP 201/202) — IEC (2013)
- Engineered Materials Handbook Vol.2 — Engineering Plastics — ASM International (1988)
- Industrial paper-phenolic laminate (XXX/XXXP/XXXPC) datasheets — Norplex-Micarta / Franklin Fibre / (2023)
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.