BERGQUIST® SIL PAD TSP 1800ST Soft-Tack Electrically Insulating Thermally Conductive Elastomer (formerly SIL-PAD 1500ST)
BERGQUIST SIL PAD TSP 1800ST is a fiberglass-reinforced thermal interface elastomer that is naturally tacky on both sides, delivering 1.8 W/(m·K) thermal conductivity and thermal impedance of 0.23°C·in²/W at 50 psi. The 0.203 mm pad is designed for auto-dispensing and auto-placement in high-volume assemblies with dielectric breakdown voltage of 3,000 Vac across an operating range of -60°C to +180°C. The naturally tacky surface allows repositionable placement without separate adhesive layers, with UL 94 V-0 flammability.
Key Properties
- Thermal Conductivity: 1.8 W/(m·K) (ASTM D5470)
- Thermal Impedance @ 50 psi: 0.23 °C·in²/W
- Dielectric Breakdown Voltage: 3,000 Vac (ASTM D149)
- Hardness: 75 Shore 00 (ASTM D2240)
- Operating Temperature Range: -60°C to +180°C
- Total Thickness: 0.203 mm
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- Specifications
- Applications
- General Info
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Physical Properties
| Property | Value | Test Method |
| Technology | Silicone | — |
| Appearance | Blue | — |
| Reinforcement Carrier | Fiberglass | — |
| Total Thickness | 0.203 mm | ASTM D374 |
| Operating Temperature Range | -60°C to +180°C | — |
Mechanical Properties
| Property | Value | Test Method |
| Hardness, Shore 00 | 75 | ASTM D2240 |
| Breaking Strength | 0.34 kN/m | ASTM D1458 |
| Elongation, 45° to Warp and Fill | 22% | ASTM D412 |
| Tensile Strength | 1.6 MPa | ASTM D412 |
Thermal Properties
| Property | Value | Test Method |
| Thermal Conductivity | 1.8 W/(m·K) | ASTM D5470 |
Thermal Performance vs. Pressure
| Property | Value | Test Method |
| TO-220 Thermal Performance @ 10 psi | 1.54 °C/W | ASTM D5470 |
| Thermal Impedance @ 10 psi | 0.37 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 25 psi | 1.52 °C/W | ASTM D5470 |
| Thermal Impedance @ 25 psi | 0.28 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 50 psi | 1.51 °C/W | ASTM D5470 |
| Thermal Impedance @ 50 psi | 0.23 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 100 psi | 1.49 °C/W | ASTM D5470 |
| Thermal Impedance @ 100 psi | 0.21 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 200 psi | 1.46 °C/W | ASTM D5470 |
| Thermal Impedance @ 200 psi | 0.2 °C·in²/W | ASTM D5470 |
Electrical Properties
| Property | Value | Test Method |
| Dielectric Breakdown Voltage | 3,000 Vac | ASTM D149 |
| Dielectric Constant @ 1,000 Hz | 6.1 | ASTM D150 |
| Volume Resistivity | 1 × 10¹¹ ohm-meter | ASTM D257 |
Flame & Fire Performance
| Property | Value | Test Method |
| Flammability Rating | V-0 | UL 94 |
Compliance
- UL 94 — Compliant (V-0)
- High-volume auto-placement of thermal interface pads between power devices and heat sinks
- Power supply thermal interface insulation in automated assembly
- Automotive electronics thermal interface
- Motor control power device isolation
- Repositionable thermal pads for in-process rework
Common industries: power electronics, automotive electronics, motor controls, and high-volume electronics manufacturing.
BERGQUIST SIL PAD TSP 1800ST is an electrically insulating, thermally conductive, soft-tack elastomeric material. The fiberglass-reinforced construction is naturally tacky on both sides, supplied in sheet or roll form for exceptional auto-dispensing and auto-placement performance in high-volume assemblies.
The natural tack also makes the pad repositionable during assembly, and it is intended for placement between an electronic power device and its heat sink without the need for a separate adhesive layer. The grade is positioned for high-volume power supply, automotive electronics, and motor control assembly lines.
Mechanical performance includes 75 Shore 00 hardness (notably softer than the firmer fiberglass-reinforced Sil-Pad grades, which are measured in Shore A), 0.34 kN/m breaking strength, 22% elongation at 45° to warp and fill, and 1.6 MPa tensile strength. Electrically, the dielectric breakdown voltage is 3,000 Vac, dielectric constant at 1,000 Hz is 6.1, and volume resistivity is 1 × 10¹¹ ohm-meter.
Thermally, the material delivers 1.8 W/(m·K) thermal conductivity, with TO-220 thermal performance ranging from 1.54°C/W at 10 psi to 1.46°C/W at 200 psi, and thermal impedance from 0.37°C·in²/W at 10 psi to 0.2°C·in²/W at 200 psi. Operating temperature range is -60°C to +180°C, and the material is UL 94 V-0 flame retardant.
Compliant with UL 94 V-0 (flame retardancy) and the listed ASTM test methods: ASTM D374, D2240, D1458, D412, D149, D150, D257, and D5470.
What differentiates SIL PAD TSP 1800ST from other SIL PAD TSP grades?
TSP 1800ST is the soft-tack grade in the Sil-Pad family, naturally tacky on both sides and measured at 75 Shore 00 — significantly softer than the 85 to 92 Shore A of the firmer fiberglass-reinforced grades (TSP 900, 1600S, 3500). The natural tack enables auto-dispensing and auto-placement in high-volume assembly without a separate adhesive layer, and the pad is repositionable during placement. It delivers the lowest thermal impedance at 50 psi in the line (0.23 °C·in²/W) and second-highest thermal conductivity (1.8 W/m·K), at the trade-off of lower dielectric breakdown voltage (3,000 Vac).
Why does thermal conductivity matter in material selection?
The function of a Sil-Pad insulator is to transfer heat from a power device to a heat sink while keeping the two electrically isolated. Thermal conductivity sets the bulk heat transport, and thermal impedance — which includes interfacial resistance and is pressure-dependent — determines real-world performance. TSP 1800ST delivers 1.8 W/(m·K) and 0.23 °C·in²/W at 50 psi, with the naturally tacky surface providing intimate contact across the interface without the need for adhesive or pre-conditioning.
What is the operating temperature range for SIL PAD TSP 1800ST?
The operating temperature range is -60°C to +180°C.
Is SIL PAD TSP 1800ST suitable for flame-rated electronics environments?
Yes. The material is rated UL 94 V-0 for flammability, making it suitable for power supply, automotive electronics, motor control, and other UL-rated assemblies that require flame-retardant thermal interface insulation.
How should SIL PAD TSP 1800ST be specified?
Specify grade (BERGQUIST SIL PAD TSP 1800ST), thickness (0.203 mm), part geometry (sheet, roll, die-cut, or kiss-cut), auto-placement format if required, dielectric and thermal impedance requirements at target pressure, UL 94 V-0 flame rating, and finished format. Note that the pad is naturally tacky on both sides — no separate pressure-sensitive adhesive is required.
