NP320 Linen Phenolic Laminate Sheet
NP320 Linen Phenolic Laminate Sheet is constructed from fine weave cotton fabric (less than 4 oz/sq yd) — commonly called linen — combined with a phenolic resin system, meeting or exceeding the requirements of ANSI/NEMA IM 60000-2021 Grade L, MIL-I-24768/15 FBI, and IEC-60893-4-PF CC 203. The fine weave construction provides better machining than NP310 and is suited for smaller and more intricate shapes requiring finer surface finish, with a compressive strength of 38,000 psi flatwise — the highest in the linen and canvas phenolic laminate line. Not UL Listed.
Key Properties
- Flexural Strength, Condition A LW / CW: 24,500 / 18,500 psi (168.9) / (127.6) MPa (ASTM D790)
- Flexural Modulus, Condition A LW / CW: 1,700 / 1,300 kpsi (11.7) / (9.0) GPa (ASTM D790)
- Tensile Strength, Condition A LW / CW: 14,000 / 10,000 psi (96.5) / (68.9) MPa (ASTM D638)
- Izod Impact Strength, Condition E-48/50 LW / CW: 1.70 / 1.35 ft-lb/in (0.91) / (0.72) J/cm (ASTM D256)
- Compressive Strength, Condition A Flatwise: 38,000 psi (262.0) MPa (ASTM D695)
- Temperature Index — Electrical / Mechanical: 115 / 125°C (UL Bulletin 746b)
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- Specifications
- Applications
- General Info
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Physical Properties
| Property | Value | Test Method |
| Specific Gravity | 1.34 | ASTM D792 |
| Rockwell Hardness (0.250″ Build-up) | 100 M Scale | ASTM D785 |
| Moisture Absorption, Condition D₁-24/23 | 2.30% | ASTM D570 |
| Flexural Strength, Condition A LW / CW | 24,500 / 18,500 psi (168.9) / (127.6) MPa | ASTM D790 |
| Flexural Modulus, Condition A LW / CW | 1,700 / 1,300 kpsi (11.7) / (9.0) GPa | ASTM D790 |
| Tensile Strength, Condition A LW / CW | 14,000 / 10,000 psi (96.5) / (68.9) MPa | ASTM D638 |
| Izod Impact Strength, Condition E-48/50 LW / CW | 1.70 / 1.35 ft-lb/in (0.91) / (0.72) J/cm | ASTM D256 |
| Compressive Strength, Condition A Flatwise | 38,000 psi (262.0) MPa | ASTM D695 |
| Bonding Strength, Condition A | 2,000 lb (907.2) kg | ASTM D229 |
| Shear Strength, Condition A Perpendicular | 13,500 psi (93.1) MPa | ASTM D732 |
Thermal Properties
| Property | Value | Test Method |
| Temperature Index — Electrical / Mechanical | 115 / 125°C | UL Bulletin 746b |
| Coefficient of Thermal Expansion, X-axis / Y-axis | 18.0 / 19.0 (“/”/°C × 10⁻⁶) | IPC-TM 650-2.4.24 |
| Flammability Rating, Condition A | HB | UL Bulletin 94 |
Electrical Properties
| Property | Value | Test Method |
| Dissipation Factor @ 1 MHz, Condition D-24/23 | 0.070 | ASTM D150 |
| Relative Permittivity @ 1 MHz, Condition D-24/23 | 5.80 | ASTM D150 |
| Breakdown Voltage, Condition A | 45 kVolts | ASTM D149 |
| Breakdown Voltage, Condition D-48/50 | 2 kVolts | ASTM D149 |
| Electric Strength, Condition A | 575 Volts/mil (226.4) kV/cm | ASTM D149 |
| Electric Strength, Condition D-48/50 | 450 Volts/mil (177.2) kV/cm | ASTM D149 |
| Arc Resistance, Condition A | 15 sec | ASTM D495 |
| Comparative Tracking Index | 170 V | ASTM D3638 |
Compliance
- ANSI/NEMA IM 60000-2021 Grade L — Meets or exceeds
- MIL-I-24768/15 FBI — Meets or exceeds
- IEC-60893-4-PF CC 203 — Meets or exceeds
- Small and intricate precision-machined phenolic components requiring fine surface finish
- Gears, washers, bushings, and spacers requiring tight dimensional tolerances
- Electrical insulation components in mechanical assemblies
- Structural insulation requiring NEMA Grade L and highest compressive strength in the phenolic line
- Military applications requiring MIL-I-24768/15 FBI compliance
Common industries: Electrical Equipment Manufacturing, Defense, Industrial Manufacturing, Precision Machining, Mechanical Power Transmission.
NP320 Linen Phenolic Laminate Sheet is the NEMA Grade L fine linen entry in the Norplex-Micarta phenolic laminate line, constructed from fine weave cotton fabric (less than 4 oz/sq yd) impregnated with a phenolic resin system.
The fine linen weave provides better machinability than NP310’s heavier canvas construction and enables smaller and more intricate shapes with finer surface finish — making NP320 the preferred selection when precision-machined detail, tight tolerances, and smooth surface quality are the primary requirements.
Compressive strength reaches 38,000 psi flatwise — the highest in the canvas and linen phenolic laminate family — and tensile strength is 14,000 / 10,000 psi (LW/CW).
The material includes dissipation factor (0.070 at 1 MHz, Condition D-24/23) and relative permittivity (5.80) data and achieves a comparative tracking index of 170 V and arc resistance of 15 seconds — the highest CTI in the phenolic laminate line. Moisture absorption is 2.30%; applications requiring improved moisture resistance in moderate humidity should specify NP320E (NEMA Grade LE). Temperature index is 115°C electrical / 125°C mechanical and flammability is rated HB.
Meets or exceeds ANSI/NEMA IM 60000-2021 Grade L, MIL-I-24768/15 FBI, and IEC-60893-4-PF CC 203.
What differentiates NP320 Linen Phenolic Laminate Sheet from NP310 and NP342?
NP320 uses a fine weave linen (less than 4 oz/sq yd cotton) construction — the finest weave in the phenolic laminate line — enabling better machining, tighter tolerances, and finer surface finish than either NP310 (heavier canvas) or NP342 (intermediate canvas). It delivers the highest compressive strength in the family (38,000 psi) and the highest comparative tracking index (170 V). NP320 is classified NEMA Grade L rather than Grade C, and meets MIL-I-24768/15 FBI. Applications requiring maximum impact resistance should specify NP310; applications prioritizing machinability and fine finish at lower cost than NP320 should specify NP342.
Why does surface finish matter when selecting a phenolic laminate for precision machining?
Phenolic laminates are machined to final component dimensions in many applications. Coarser fabric weaves leave a rougher machined surface that may require additional finishing steps, introduce dimensional variability along fabric boundaries, or limit the minimum feature size that can be machined cleanly. NP320's fine linen weave produces a more homogeneous machined surface, allowing tighter dimensional tolerances and smaller feature sizes — critical for gears, bushings, and precision spacers where surface condition affects fit, function, and wear life.
What is the temperature index for NP320 Linen Phenolic Laminate Sheet?
The temperature index is 115°C electrical / 125°C mechanical, as listed on the Technical Datasheet.
Is NP320 Linen Phenolic Laminate Sheet suitable for military and regulated environments?
Yes. NP320 meets or exceeds ANSI/NEMA IM 60000-2021 Grade L, MIL-I-24768/15 FBI, and IEC-60893-4-PF CC 203. NP320 is not UL Listed and carries a UL 94 HB flammability rating. Applications in moderate humidity should consider NP320E (NEMA Grade LE) which offers improved moisture resistance.
How should NP320 Linen Phenolic Laminate Sheet be specified?
Specify grade (NP320 Linen Phenolic Laminate Sheet), thickness, compliance requirements (NEMA Grade L, MIL-I-24768/15, or IEC-60893-4-PF CC 203 as applicable), dimensional tolerances, and finished format.
