NP320E Moisture-Resistant Linen Phenolic Laminate Sheet
NP320E Moisture-Resistant Linen Phenolic Laminate Sheet is similar to NP320 with improved moisture resistance, certifiable to ANSI/NEMA IM 60000-2021 Grade LE, ASTM D709 Type II Grade LE, ASTM F2953-12 Type FB, and MIL-I-24768/13 FBE. The material is suitable for electrical applications in moderate humidity conditions, with a moisture absorption of 1.90% — lower than NP320’s 2.30% — and delivers a breakdown voltage of 50 kV (Condition A) and electric strength of 625 Volts/mil (Condition A). Not UL Listed.
Key Properties
- Flexural Strength, Condition A LW / CW: 22,000 / 16,000 psi (151.7) / (110.3) MPa (ASTM D790)
- Flexural Modulus, Condition A LW / CW: 1,600 / 1,200 kpsi (11.0) / (8.3) GPa (ASTM D790)
- Tensile Strength, Condition A LW / CW: 13,000 / 9,000 psi (89.6) / (62.1) MPa (ASTM D638)
- Izod Impact Strength, Condition E-48/50 LW / CW: 1.35 / 1.10 ft-lb/in (0.72) / (0.59) J/cm (ASTM D256)
- Compressive Strength, Condition A Flatwise: 36,000 psi (248.2) MPa (ASTM D695)
- Moisture Absorption, Condition D₁-24/23: 1.90% (ASTM D570)
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- Specifications
- Applications
- General Info
- FAQs
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 | 1.90% | ASTM D570 |
| Flexural Strength, Condition A LW / CW | 22,000 / 16,000 psi (151.7) / (110.3) MPa | ASTM D790 |
| Flexural Modulus, Condition A LW / CW | 1,600 / 1,200 kpsi (11.0) / (8.3) GPa | ASTM D790 |
| Tensile Strength, Condition A LW / CW | 13,000 / 9,000 psi (89.6) / (62.1) MPa | ASTM D638 |
| Izod Impact Strength, Condition E-48/50 LW / CW | 1.35 / 1.10 ft-lb/in (0.72) / (0.59) J/cm | ASTM D256 |
| Compressive Strength, Condition A Flatwise | 36,000 psi (248.2) MPa | ASTM D695 |
| Bonding Strength, Condition A | 1,900 lb (861.8) 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 | 125 / 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 | 0.065 | ASTM D150 |
| Relative Permittivity @ 1 MHz, Condition D-24/23 | 5.50 | ASTM D150 |
| Breakdown Voltage, Condition A | 50 kVolts | ASTM D149 |
| Breakdown Voltage, Condition D-48/50 | 5 kVolts | ASTM D149 |
| Electric Strength, Condition A | 625 Volts/mil (246.1) kV/cm | ASTM D149 |
| Electric Strength, Condition D-48/50 | 500 Volts/mil (196.9) 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 LE — Certifiable
- ASTM D709 Type II Grade LE — Certifiable
- ASTM F2953-12 Type FB — Certifiable
- MIL-I-24768/13 FBE — Certifiable
- Electrical insulation components in moderate humidity environments
- Precision-machined linen phenolic parts requiring Grade LE moisture resistance
- Switchgear and electrical equipment insulation in humid industrial environments
- Structural insulation requiring NEMA Grade LE and MIL-I-24768/13 FBE compliance
- Replacement for NP320 where ambient humidity degrades electrical performance
Common industries: Electrical Equipment Manufacturing, Defense, Industrial Manufacturing, Marine Electrical Systems, General Engineering.
NP320E Moisture-Resistant Linen Phenolic Laminate Sheet is the NEMA Grade LE variant of the linen phenolic laminate line, engineered with improved moisture resistance compared to standard NP320 (Grade L) and suitable for electrical applications in moderate humidity conditions.
The Grade LE classification specifically addresses moisture-related degradation of electrical performance — a critical factor in environments where elevated ambient humidity reduces dielectric strength and increases current leakage paths through insulating components. Moisture absorption is 1.90% vs. 2.30% for NP320, and breakdown voltage in the wet condition (Condition D-48/50) is 5 kV — higher than NP320’s 2 kV.
Electric strength reaches 625 Volts/mil (Condition A) / 500 Volts/mil (Condition D-48/50), with a comparative tracking index of 170 V and arc resistance of 15 seconds. The temperature index is 125°C electrical / 125°C mechanical — 10°C higher electrically than standard NP320 (115°C). Dissipation factor at 1 MHz is 0.065 and relative permittivity is 5.50. Flammability is rated HB per UL Bulletin 94. NP320E is not UL Listed.
Certifiable to ANSI/NEMA IM 60000-2021 Grade LE, ASTM D709 Type II Grade LE, ASTM F2953-12 Type FB, and MIL-I-24768/13 FBE.
What differentiates NP320E Moisture-Resistant Linen Phenolic Laminate Sheet from NP320?
NP320E (NEMA Grade LE) is formulated for improved moisture resistance compared to NP320 (NEMA Grade L). Moisture absorption is 1.90% vs. 2.30% for NP320, and wet-condition breakdown voltage (Condition D-48/50) is 5 kV vs. 2 kV — a meaningful improvement in applications where dielectric performance must be maintained in humid environments. The temperature index is also 10°C higher electrically (125°C vs. 115°C). The trade-off is slightly lower mechanical properties: flexural strength is 22,000 / 16,000 psi vs. 24,500 / 18,500 psi for NP320.
Why does moisture resistance matter when selecting a linen phenolic laminate for electrical applications?
Phenolic laminates absorb moisture from ambient air, and absorbed moisture significantly reduces dielectric strength — a phenomenon captured by the difference between Condition A (dry) and Condition D-48/50 (wet) test values. In electrical insulation applications where the component is exposed to elevated humidity, the wet-condition breakdown voltage is the operationally relevant value. NP320E's Grade LE formulation maintains a higher breakdown voltage (5 kV) and electric strength (500 Volts/mil) under wet conditions, providing a more reliable insulation margin in moderate humidity service.
What is the temperature index for NP320E Moisture-Resistant Linen Phenolic Laminate Sheet?
The temperature index is 125°C electrical / 125°C mechanical, as listed on the Technical Datasheet.
Is NP320E Moisture-Resistant Linen Phenolic Laminate Sheet suitable for military and regulated environments?
Yes. NP320E is certifiable to ANSI/NEMA IM 60000-2021 Grade LE, ASTM D709 Type II Grade LE, ASTM F2953-12 Type FB, and MIL-I-24768/13 FBE. NP320E is not UL Listed and carries a UL 94 HB flammability rating.
How should NP320E Moisture-Resistant Linen Phenolic Laminate Sheet be specified?
Specify grade (NP320E Moisture-Resistant Linen Phenolic Laminate Sheet), thickness, compliance requirements (NEMA Grade LE, MIL-I-24768/13, ASTM D709, or ASTM F2953-12 as applicable), dimensional tolerances, and finished format.
