Phenolic XX FR
Flame-retardant grade
ASTM D709 · also Garolite XX, Bakelite
FR = flame-retardant paper phenolic
Pick where a UL 94 V-0 rating is mandated for the insulating part (appliance and switchgear insulation).
Values for the FR condition
Other Phenolic XX grades and fills
Phenolic XX is listed in 6 conditions; see the grade overview at Phenolic XX.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
NEMA XXXPC | Pick for high-volume cold blanking of thin insulation parts without pre-heating the sheet. | — | 76 | 1.6 | 87 Shore D |
NEMA XXXP | Pick for thin sheet that must be blanked/punched (terminal strips, washers) while keeping good electrical loss figures. | — | 80 | 1.5 | 88 Shore D |
NEMA XXX | Pick for radio-frequency or humid-environment insulation where low loss and low moisture pickup matter more than strength. | — | 83 | 1.4 | 89 Shore D |
FRThis page Flame-retardant paper phenolic | Pick where a UL 94 V-0 rating is mandated for the insulating part (appliance and switchgear insulation). | — | 85 | 1.4 | 90 Shore D |
Phenolic MatrixDefault NEMA XX cellulose-paper / phenolic laminate (default) | General-purpose paper-phenolic sheet/rod/tube for combined mechanical and low-frequency electrical duty at low cost. | — | 90 | 1.5 | 90 Shore D |
NEMA X | Pick when only mechanical strength matters (spacers, jigs, wear pads) and electrical performance is irrelevant. | — | 100 | 1.6 | 91 Shore D |
What is Phenolic XX FR?
Phenolic XX FR is Phenolic XX in the FR grade — pick where a UL 94 V-0 rating is mandated for the insulating part (appliance and switchgear insulation). Phenolic XX FR has a tensile strength of 85 MPa (12.3 ksi), weaker than 75% of composite grades. Elongation at break is 1.4% and the elastic modulus is 7 GPa (1.02 Msi). Phenolic XX FR has a density of 1.34 g/cm³ (0.0484 lb/in³), lighter than 78% of composite grades. Its glass-transition temperature is 170°C (338 °F). Phenolic Matrix is the default condition FabDigit quotes; FR is available on request or by drawing note.
Advantages
- Easy to machine — 78/100, better than 80% of composite grades
- Low embodied carbon — 4.5 kg CO₂/kg, better than 79% of composite grades
- Lightweight — 1.34 g/cm³ (0.0484 lb/in³), better than 78% of composite grades
Limitations
- Degrades in UV without stabilisers — 25/100, worse than 86% of composite grades
- Limited service temperature — 120°C (248 °F), worse than 78% of composite grades
- Low stiffness — 7 GPa (1.02 Msi), worse than 77% of composite grades
- Absorbs moisture — dry before molding — 1.3%, worse than 75% of composite grades
Phenolic XX FR properties
Typical room-temperature values for Phenolic XX FR; 23 are specific to this condition. Other listed values are Phenolic XX reference data and may not represent this condition. Bars are the position among composite grades.
Physical4
Phenolic XX FR has a density of 1.34 g/cm³ (0.0484 lb/in³), lighter than 78% of composite grades. Its glass-transition temperature is 170°C (338 °F).
Mechanical14
Phenolic XX FR has a tensile strength of 85 MPa (12.3 ksi), weaker than 75% of composite grades. Elongation at break is 1.4% and the elastic modulus is 7 GPa (1.02 Msi).
Thermal10
Phenolic XX FR is rated for continuous service to 120°C (248 °F). It conducts heat at 0.26 W/m·K (0.15 BTU/hr·ft·°F), worse than 71% of composite grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical7
Phenolic XX FR is an electrical insulator with a dielectric strength of 15 kV/mm (381 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (65/100), worse than 72% of composite grades. UV resistance is poor.
Sustainability3
Producing a kilogram of Phenolic XX FR takes about 80 MJ of energy and emits 4.5 kg of CO₂ — less than 84% of composite grades. Typical recycled content is 5%.
Manufacturability4
Phenolic XX FR's machinability is very good (78/100, better than 80% of composite grades); weldability not recommended (0/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Phenolic XX FR
Is Phenolic XX easy to machine?
Cuts, drills and turns easily with sharp carbide tooling at high speed and no coolant; dust is abrasive and irritating, so use vacuum extraction and back up holes to avoid edge chipping and delamination.
Can Phenolic XX be welded?
Thermoset — cannot be welded or thermally reformed; join by bolting, riveting or epoxy/phenolic adhesive bonding after abrading the surface.
Can Phenolic XX be formed, bent or molded?
Supplied as fully cured sheet, rod and tube; thin sheet (P/PC grades) can be hot- or cold-punched, but thick stock must be machined to shape.
What surface finishes work on Phenolic XX?
Sand or scrape edges to remove fuzz and seal machined surfaces with varnish/epoxy to limit moisture pickup; the natural finish is brown-to-black and not platable, though it accepts primer-based paint.
Phenolic XX 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, fully cured thermoset binder | 40 – 55 | 48 |
| volatiles/residual moisture | 0 – 2 | 1 |
| cellulose kraft paperreinforcement web, multiple plies | ≥ 45 (balance) | — |
Phenolic XX FR — frequently asked
What is Phenolic XX FR used for?
Phenolic XX FR is typically used for electrical insulators and barriers, terminal boards and tag strips, punched washers, gaskets and shims, coil and transformer spacers, switch and relay bases and low-load bushings and cams. In short: classic phenolic laminate.
What is the tensile strength of Phenolic XX FR?
Phenolic XX FR has a typical tensile strength of 85 MPa (12.3 ksi) — weaker than 75% of composite grades. Strength varies by condition: see the 6 listed tempers.
Is Phenolic XX FR easy to machine?
Yes — machinability is rated very good (78/100, better than 80% of composite grades). Cuts, drills and turns easily with sharp carbide tooling at high speed and no coolant; dust is abrasive and irritating, so use vacuum extraction and back up holes to avoid edge chipping and delamination.
Can Phenolic XX FR be welded?
Not readily — weldability is rated not recommended (0/100). Thermoset — cannot be welded or thermally reformed; join by bolting, riveting or epoxy/phenolic adhesive bonding after abrading the surface.
What surface finishes work on Phenolic XX FR?
Sand or scrape edges to remove fuzz and seal machined surfaces with varnish/epoxy to limit moisture pickup; the natural finish is brown-to-black and not platable, though it accepts primer-based paint.
Can Phenolic XX FR be formed, bent or molded?
Supplied as fully cured sheet, rod and tube; thin sheet (P/PC grades) can be hot- or cold-punched, but thick stock must be machined to shape.
What is the maximum service temperature of Phenolic XX FR?
Phenolic XX FR is rated for continuous use to about 120°C (248 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in Phenolic XX FR?
Yes — Phenolic XX FR is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- NEMA LI 1 — Industrial Laminating Thermosetting Products — NEMA (1998)
- ASTM D709 — Standard Specification for Laminated Thermosetting Materials — ASTM (2017)
- Paper-phenolic industrial laminate grades X / XX / XXX / XXXP — Norplex-Micarta (2022)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics (phenolic laminates) — ASM International (1988)
- MatWeb paper-reinforced phenolic laminate property listings — MatWeb (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.