BERGQUIST® SIL PAD TSP 3500 Higher-Performance High-Reliability Silicone / Fiberglass Insulator (formerly SIL-PAD 2000)
BERGQUIST SIL PAD TSP 3500 is a high-performance fiberglass-reinforced silicone elastomer insulator engineered for aerospace, avionics, and other high-reliability electronic packaging, delivering 3.5 W/(m·K) thermal conductivity — the highest in the Sil-Pad family — and thermal impedance of 0.33°C·in²/W at 50 psi (at 0.01″ thickness). The pad provides dielectric breakdown voltage of 4,000 Vac across an extended operating range of -60°C to +200°C, available in 0.254 to 0.508 mm thickness with UL 94 V-0 flammability. Grease-free and conformable.
Key Properties
- Thermal Conductivity: 3.5 W/(m·K) (ASTM D5470)
- Thermal Impedance @ 50 psi (0.01″): 0.33 °C·in²/W
- Dielectric Breakdown Voltage: 4,000 Vac (ASTM D149)
- Hardness: 90 Shore A (ASTM D2240)
- Operating Temperature Range: -60°C to +200°C
- Total Thickness: 0.254 to 0.508 mm
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Technology | Silicone | — |
| Appearance | White | — |
| Reinforcement Carrier | Fiberglass | — |
| Total Thickness | 0.254 to 0.508 mm | ASTM D374 |
| Operating Temperature Range | -60°C to +200°C | — |
Mechanical Properties
| Property | Value | Test Method |
| Hardness, Shore A | 90 | ASTM D2240 |
Thermal Properties
| Property | Value | Test Method |
| Thermal Conductivity | 3.5 W/(m·K) | ASTM D5470 |
Thermal Performance vs. Pressure (@ 0.01″ Thickness)
| Property | Value | Test Method |
| TO-220 Thermal Performance @ 10 psi | 2.61 °C/W | ASTM D5470 |
| Thermal Impedance @ 10 psi | 0.57 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 25 psi | 2.32 °C/W | ASTM D5470 |
| Thermal Impedance @ 25 psi | 0.43 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 50 psi | 2.02 °C/W | ASTM D5470 |
| Thermal Impedance @ 50 psi | 0.33 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 100 psi | 1.65 °C/W | ASTM D5470 |
| Thermal Impedance @ 100 psi | 0.25 °C·in²/W | ASTM D5470 |
| TO-220 Thermal Performance @ 200 psi | 1.37 °C/W | ASTM D5470 |
| Thermal Impedance @ 200 psi | 0.2 °C·in²/W | ASTM D5470 |
Electrical Properties
| Property | Value | Test Method |
| Dielectric Breakdown Voltage | 4,000 Vac | ASTM D149 |
| Dielectric Constant @ 1,000 Hz | 4.0 | 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)
- Aerospace and avionics electronic packaging insulation
- Power supply thermal interface for high-reliability designs
- Motor control power device isolation
- Power semiconductor thermal interface
- High-temperature thermal management up to +200°C
Common industries: aerospace, avionics, power electronics, motor controls, and high-reliability electronics packaging.
BERGQUIST SIL PAD TSP 3500 is a higher-performance, high-reliability thermally conductive insulator designed for demanding aerospace, avionics, and commercial electronic packaging applications.
The silicone elastomer is formulated to maximize the thermal and dielectric performance of the filler/binder matrix, producing a grease-free, conformable material capable of meeting or exceeding the thermal and electrical requirements of high-reliability electronic packaging. Within the Sil-Pad family, TSP 3500 delivers the highest thermal conductivity (3.5 W/m·K) and the broadest operating temperature range (up to +200°C).
Mechanical performance includes 90 Shore A hardness. Electrically, the dielectric breakdown voltage is 4,000 Vac, dielectric constant at 1,000 Hz is 4.0, and volume resistivity is 1 × 10¹¹ ohm-meter.
Thermally, the material delivers 3.5 W/(m·K) thermal conductivity, with TO-220 thermal performance ranging from 2.61°C/W at 10 psi to 1.37°C/W at 200 psi, and thermal impedance from 0.57°C·in²/W at 10 psi to 0.2°C·in²/W at 200 psi (measured at 0.01″ thickness). Operating temperature range is -60°C to +200°C, and the material is UL 94 V-0 flame retardant. Total thickness is available from 0.254 to 0.508 mm.
Compliant with UL 94 V-0 (flame retardancy) and the listed ASTM test methods: ASTM D374, D2240, D149, D150, D257, and D5470.
What differentiates SIL PAD TSP 3500 from other SIL PAD TSP grades?
TSP 3500 is the highest-performance fiberglass-reinforced grade in the Sil-Pad family, delivering 3.5 W/(m·K) thermal conductivity (versus 0.9 for TSP 900, 1.6 for TSP 1600S, and 1.8 for TSP 1800ST) and an extended +200°C operating temperature ceiling that exceeds the +180°C of the other Sil-Pad grades. It is engineered specifically for aerospace, avionics, and other high-reliability applications, and is supplied as a grease-free conformable elastomer in a thickness range of 0.254 to 0.508 mm — the thickest range in the family.
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 3500 delivers 3.5 W/(m·K) and 0.33 °C·in²/W at 50 psi (0.01"), the highest thermal conductivity and lowest thermal impedance at typical mounting pressure of any fiberglass-reinforced grade in the Sil-Pad family.
What is the operating temperature range for SIL PAD TSP 3500?
The operating temperature range is -60°C to +200°C.
Is SIL PAD TSP 3500 suitable for aerospace, avionics, and flame-rated electronics environments?
Yes. The material is rated UL 94 V-0 for flammability and is engineered for aerospace, avionics, and other high-reliability electronic packaging applications, with the +200°C upper service limit supporting demanding thermal duty cycles.
How should SIL PAD TSP 3500 be specified?
Specify grade (BERGQUIST SIL PAD TSP 3500), thickness (within 0.254 to 0.508 mm range), part geometry (sheet, die-cut, or kiss-cut), dielectric and thermal impedance requirements at target pressure, operating temperature requirements (up to +200°C), UL 94 V-0 flame rating, and finished format.
