Kapton® MT+ Thermally Conductive Polyimide Film
Kapton® MT+ is a homogeneous polyimide film possessing nearly twice the thermal conductivity of Kapton® MT and four times that of standard Kapton® HN, with thermal conductivity of 0.75 W/m·K across all grades. Tensile strength is 12 kpsi (83 MPa) and modulus is 625 kpsi (4.3 GPa) across all grades; dielectric strength ranges from 3.9–5.3 kVAC/mil (154–209 kV/mm) depending on grade. Available in 150MT+, 200MT+, and 300MT+ grades at 1.5–3.0 mil thickness.
Key Properties
- Thermal Conductivity: 0.75 W/m·K, all grades — ASTM D5470
- Tensile Strength: 12 kpsi (83 MPa), all grades — ASTM D882
- Elongation to Break: 150MT+: 44%; 200MT+: 44%; 300MT+: 35% — ASTM D882
- Dielectric Strength: 150MT+: 5.3 kVAC/mil (209 kV/mm); 200MT+: 5.0 kVAC/mil (197 kV/mm); 300MT+: 3.9 kVAC/mil (154 kV/mm) — ASTM D1491 (1/4 in brass electrode)
- Thickness: 150MT+: 1.5 mil (0.038 mm); 200MT+: 2.0 mil (0.050 mm); 300MT+: 3.0 mil (0.076 mm) — ASTM D374
- Tensile Modulus: 625 kpsi (4.3 GPa), all grades — ASTM D882
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | 150MT+ | 200MT+ | 300MT+ | Test Method |
| Thickness, mils (mm) | 1.5 (0.038) | 2.0 (0.050) | 3.0 (0.076) | ASTM D374 |
| Tensile Strength, kpsi (MPa) | 12 (83) | 12 (83) | 12 (83) | ASTM D882 |
| Tensile Modulus, kpsi (GPa) | 625 (4.3) | 625 (4.3) | 625 (4.3) | ASTM D882 |
| Elongation to Break, % | 44 | 44 | 35 | ASTM D882 |
| Area Factor, ft²/lb (m²/kg) | 76 (15.6) | 57.5 (11.8) | 38.1 (7.8) | N/A |
Electrical Properties
| Property | 150MT+ | 200MT+ | 300MT+ | Test Method |
| Dielectric Strength, kVAC/mil (kV/mm)* | 5.3 (209) | 5.0 (197) | 3.9 (154) | ASTM D1491 |
| Surface Resistivity, Ω | >10¹⁵ | >10¹⁵ | >10¹⁵ | ASTM D257 |
| Volume Resistivity, Ω·cm | >10¹⁵ | >10¹⁵ | >10¹⁵ | ASTM D257 |
*Tested with 1/4 in brass electrode.
Thermal Properties
| Property | 150MT+ | 200MT+ | 300MT+ | Test Method |
| Thermal Conductivity, W/m·K | 0.75 | 0.75 | 0.75 | ASTM D5470 |
Flame & Fire Performance
| Property | 150MT+ | 200MT+ | 300MT+ | Test Method |
| Flammability | V-0 | V-0 | V-0 | UL94 |
Compliance
- UL94 — Compliant (V-0, all grades)
- Thermal interface material substrate requiring the highest available thermal conductivity in a flexible polyimide film
- PTC heater module insulation where heat transfer through the dielectric layer is central to device function
- Motor slot insulation and phase separators in electric motors requiring thermally conductive, electrically isolating film
- Power supply insulation where ceramic board replacement with a thermally conductive, flexible film is desired
- High-performance electronic assembly isolation where maximum heat dissipation through a dielectric film is required
Common industries: thermal management systems, electric motor manufacturing, power supply manufacturing, automotive electronics, industrial controls.
Kapton® MT+ is the highest thermal conductivity polyimide film available, with 0.75 W/m·K — nearly twice that of Kapton® MT and four times that of standard Kapton® HN — while retaining superior electrical isolation properties.
It is designed for applications where maximum heat transfer through a flexible, electrically insulating film is required, including use as a substrate for thermal interface materials, as insulation in PTC heater modules, and as motor slot insulation and phase separators. Its flex-to-fit, bend-to-install capability gives it a processing advantage over rigid ceramic board alternatives in confined assembly spaces.
Modulus is 625 kpsi (4.3 GPa) across all grades — the highest in the Kapton® MT series — providing mechanical rigidity that aids positioning and fixturing during assembly. Surface and volume resistivity both exceed 10¹⁵ Ω and 10¹⁵ Ω·cm respectively across all grades, confirming effective electrical isolation even at the elevated thermal conductivity that the MT+ formulation achieves.
Dielectric strength decreases with increasing thickness (5.3 kVAC/mil at 1.5 mil down to 3.9 kVAC/mil at 3.0 mil), consistent with standard polyimide behavior. The film is rated UL94 V-0 across all grades.
What differentiates Kapton® MT+ from Kapton® MT?
Kapton® MT+ has nearly twice the thermal conductivity of Kapton® MT (0.75 W/m·K vs. 0.46 W/m·K) and a significantly higher modulus (625 kpsi / 4.3 GPa vs. 440–490 kpsi / 3.0–3.4 GPa). The tradeoff is lower tensile strength (12 kpsi / 83 MPa vs. 20–23 kpsi / 138–159 MPa for MT) and lower elongation to break (35–44% vs. 80–100% for MT). MT+ is selected when maximum thermal conductivity is the primary requirement; MT is selected when a better balance of tensile strength, elongation, and thermal conductivity is needed.
Why does thermal conductivity matter for film selection in thermal interface applications?
As a thermal interface material substrate, the film sits directly in the thermal path between a heat-generating component and a heat spreader or heat sink. Higher thermal conductivity means lower thermal resistance through the film, which directly reduces junction temperature and improves device reliability and power density. At 0.75 W/m·K — four times standard HN and the highest available for a polyimide film — Kapton® MT+ minimizes the thermal bottleneck introduced by the dielectric layer.
What is the service temperature capability of Kapton® MT+?
No specific service temperature range is stated on the H-O Products TDS for Kapton® MT+. Contact H-O Products for additional thermal performance data.
Is Kapton® MT+ suitable for flame-rated environments?
Yes. Kapton® MT+ is rated UL94 V-0 across all grades (150MT+, 200MT+, 300MT+). No additional compliance certifications are specified on the H-O Products TDS for this material.
How should Kapton® MT+ be specified?
Specify grade (150MT+, 200MT+, or 300MT+), thickness in mils or mm, compliance requirements (UL94 V-0), dimensional tolerances, and finished format (slit roll, sheet, or die-cut component).
