Nomex® Type 411 Uncalendered Aramid Insulation Paper
Nomex® Type 411 is the uncalendered precursor of Nomex® Type 410, available in five thicknesses from 0.13 mm to 0.58 mm (5 mil to 23 mil) with a density of 0.3, giving it correspondingly lower electrical and mechanical properties and higher bulk than Type 410. It is used in applications such as motor phase insulation and transformer coil end filler where high bulk and conformability are of prime importance, and its increased impregnability and saturability make it suitable for cast resin turn and layer insulation.
Key Properties
- Tensile Strength (0.25 mm/10 mil): MD 35 N/cm, XD 20 N/cm — ASTM D828
- Elongation (0.25 mm/10 mil): MD 3.4%, XD 5.2% — ASTM D828
- Dielectric Strength, AC Rapid Rise (0.25 mm/10 mil): 240 V/mil (9 kV/mm) — ASTM D149
- Temperature Resistance: Recognized 220°C insulating material; Limiting Oxygen Index 28.5% at room temperature (0.13 mm/5 mil)
- Thickness Range: 0.13–0.58 mm (5–23 mil), 5 standard grades — TAPPI-411
- Density (0.25 mm/10 mil): 0.31 g/cc
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- Specifications
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Electrical Properties (0.25 mm/10 mil)
| Property | Value | Test Method |
| Dielectric Strength, AC Rapid Rise | 240 V/mil (9 kV/mm) | ASTM D149 |
| Full Wave Impulse | 450 V/mil (18 kV/mm) | ASTM D3426 |
| Dielectric Constant at 60 Hz | 1.2 | ASTM D150 |
| Dielectric Constant at 1 kHz | 1.3 | ASTM D150 |
| Dissipation Factor at 60 Hz | 3 x10⁻³ | ASTM D150 |
| Dissipation Factor at 1 kHz | 5 x10⁻³ | ASTM D150 |
Mechanical Properties (0.25 mm/10 mil)
| Property | Value | Test Method |
| Typical Thickness | 0.26 mm (10.2 mil) | TAPPI-411 |
| Basis Weight | 82 g/m² | ASTM D646 |
| Density | 0.31 g/cc | — |
| Tensile Strength, MD | 35 N/cm | ASTM D828 |
| Tensile Strength, XD | 20 N/cm | ASTM D828 |
| Elongation, MD | 3.4% | ASTM D828 |
| Elongation, XD | 5.2% | ASTM D828 |
| Elmendorf Tear, MD | 1.9 N | TAPPI-414 |
| Elmendorf Tear, XD | 2.5 N | TAPPI-414 |
| Initial Tear Strength, MD | 13 N | ASTM D1004 |
| Initial Tear Strength, XD | 8 N | ASTM D1004 |
| Shrinkage at 240°C, MD | 0.6% | — |
| Shrinkage at 240°C, XD | 0.9% | — |
Environmental Performance (0.13 mm/5 mil)
| Property | Value | Test Method |
| Limiting Oxygen Index at Room Temperature | 28.5% | ASTM D2863 |
| Limiting Oxygen Index at 220°C | 21.8% | ASTM D2863 |
Compliance
- 220°C Insulating Material Recognition — Compliant (based on DuPont/UL thermal aging data)
- Motor phase insulation
- Transformer coil end filler
- Cast resin turn and layer insulation
- Applications requiring high bulk and conformability
- Varnish- or resin-impregnated insulation systems
Common industries: electric motor manufacturing, transformer manufacturing, cast resin electrical component manufacturing.
Nomex® Type 411 is the uncalendered precursor of Nomex® Type 410, sharing the same chemical composition but processed to a lower density (0.3) that gives it higher bulk and greater conformability. This makes it well suited to applications such as motor phase insulation and transformer coil end filler, where high bulk and conformability are of prime importance.
Because it is uncalendered, Type 411 offers increased impregnability and saturability compared to Type 410 — in testing, hand-dipped varnish saturability improved by 40%, and vacuum-pressure impregnation saturability improved by as much as 200% — making it well suited to cast resin turn and layer insulation applications.
Type 411 also retains at least 85% of its dry dielectric strength after 6 days at 96% relative humidity, despite absorbing up to 16% water, and its tensile strength can be significantly increased through heat-treatment under certain conditions. Since Type 411 paper is chemically identical to Type 410, its electrical properties react similarly to temperature changes up to and including 220°C.
Compliant with recognition as a 220°C insulating material, based on DuPont thermal aging data for Nomex® paper.
What differentiates Nomex® Type 411 from Nomex® Type 410?
Type 411 is the uncalendered precursor of Type 410, processed to a lower density (0.3) that gives it higher bulk, greater conformability, and improved impregnability and saturability — up to 200% better with vacuum-pressure impregnation — at the cost of lower electrical and mechanical properties.
Why does tensile strength matter for film selection?
Even at its lower density, Type 411's tensile strength (up to 71 N/cm MD at 23 mil) must withstand the handling and forming stresses of motor phase insulation and transformer coil end filler fabrication without tearing.
What is the operating temperature range for Nomex® Type 411?
Nomex® Type 411 is recognized as a 220°C insulating material, with its Limiting Oxygen Index of 28.5% at room temperature (0.13 mm/5 mil) declining below the flammability threshold only above 240°C.
Is Nomex® Type 411 suitable for regulated electrical environments?
Nomex® Type 411 is recognized as a 220°C insulating material based on DuPont thermal aging data; no additional UL standard numbers are specified on the manufacturer's TDS for this grade.
How should Nomex® Type 411 be specified?
Specify grade (Nomex® Type 411), thickness, compliance requirements, dimensional tolerances, and finished format.
