Thermal conductive silicone cloth lets one thin layer carry heat from a hot component into the heat sink while keeping live metal and grounded metal electrically apart. Lixing lists this cloth with a withstand voltage above 4kV, thermal conductivity of 0.8–3.0 W/m·K and thicknesses from 0.2 to 1.0 mm. Before you order, line up three numbers: the working voltage and insulation margin you want, the assembly gap available for the sheet, and the conductivity grade your heat load calls for. Thickness is the dial that balances voltage margin against the heat path.
One sheet for heat transfer and high-voltage isolation
In power supplies and high-voltage PCBs, the metal tab of a power device often sits at circuit potential while the heat sink is grounded. An air gap traps heat, and bare metal contact creates a current path. The thermal conductive insulating silicone cloth combines silicone with fiberglass in a thin, flexible sheet that moves heat toward the heat sink while the insulating layer separates the two potentials. That is one of the practical advantages of thermally conductive silicone sheet materials in positions where a hot part must press against metal without conducting.
Benefit 1: Withstand voltage above 4kV for isolation headroom
A hot component can sit directly on its heat sink without stacking a separate insulating film. Basis: the product page lists a withstand voltage above 4kV and describes high volume resistivity, which helps reduce the risk of dielectric breakdown. The page does not state the thickness or test method behind the 4kV figure, so base your design margin on data for the thickness you actually order.
Benefit 2: 0.2–1.0 mm thickness to tune voltage margin against heat flow
A thinner sheet shortens the heat path; a thicker one adds insulation margin and fills a larger assembly gap. Basis: the product page lists thicknesses from 0.2 mm to 1.0 mm, and width, length and thickness can all be customized, so the sheet follows your working voltage and mechanical gap instead of a single stock size.
Benefit 3: 0.8–3.0 W/m·K grades matched to the heat load
Heat loads vary widely between parts, and choosing a grade that fits keeps both temperature and cost in check. Basis: the product page lists a thermal conductivity range of 0.8–3.0 W/m·K. When comparing conductivity data between suppliers, check the test conditions first, as explained in how to compare thermal silicone cloth data under four D5470 conditions.
Benefit 4: Fiberglass reinforcement helps the insulating layer survive assembly
High-voltage isolation depends on an intact sheet, and stretching, misalignment or clamping during assembly can thin it locally. Basis: the product page describes an internal fiberglass layer and tensile strength above 150 Kgf/cm², keeping the structure stable during installation and long-term use. For more on how the cloth behaves under pressure, read strength and insulation of thermal silicone cloth in lamination.
Benefit 5: UL 94 V-0 / V-1 flame rating and -30°C to 200°C operation
Power electronics run hot and often carry flame requirements, so a heat- and flame-rated insulator removes one design worry. Basis: the product page lists UL 94 V-0 / V-1, an operating range of -30°C to 200°C and hardness of 70 ± 5 Shore A.
Why thickness drives voltage capability: the dielectric strength formula
According to the Intertek summary of ASTM D149 / IEC 60243 dielectric strength testing, dielectric strength is the breakdown voltage divided by the specimen thickness:
E_b = V_b / d
- E_b: dielectric strength, kV/mm (or V/mil)
- V_b: voltage at which the specimen undergoes dielectric breakdown, kV
- d: specimen thickness, mm
In plain terms: for the same material under the same test conditions, a thicker insulating layer usually withstands a higher breakdown voltage, but heat must travel further, which is exactly the trade-off when you choose thickness. This is a test definition and engineering model, not a product specification or guarantee. Dielectric strength usually does not scale linearly with thickness and depends on electrode geometry, ramp rate, temperature, humidity, voids and surface contamination, and breakdown voltage is not a continuous working voltage. Design creepage and clearance separately to the applicable safety standard.
Where it fits
- Between power devices and heat sinks in power supplies, where heat must pass but potentials must stay apart.
- Between hot components on high-voltage PCBs and a metal enclosure or cooling module.
- Electronic thermal interfaces that need custom width, length or thickness.
What to send with your inquiry
Share the working voltage and required withstand test conditions, the available assembly gap and thickness range, the component heat load or target conductivity grade, and size and color needs. Lixing can suggest a thickness and grade from these conditions and supply samples so you can confirm the fit in your own assembly. See the full parameters on the thermal conductive silicone cloth specification page, or email yw@zh-lx.com to request samples.
Prepared by the Lixing technical editorial team from the official product page and public test-standard documentation. AI draft pending human review; values follow the product page and the specification you order.
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