BISCO® HT-6220 Soft
BISCO® HT-6220 is a soft solid silicone rated at 20 Shore A, designed for demanding gasketing applications requiring a highly protective seal with low closure force. It delivers 640 psi tensile strength, 116 ppi tear resistance, and a compression set of <25% (70 hours @ 302°F @ 25% deflection). The material is rated for service from -67°F to 392°F and provides resistance to UV, ozone, extreme temperatures, and most fluids.
Key Properties
- Durometer, Shore A: 20 — ASTM D2240
- Tensile Strength: 640 psi — ASTM D412
- Elongation: 580% — ASTM D412
- Compression Set, 70 Hours @ 302°F @ 25%: <25% — ASTM D395
- Specific Gravity: 1.08 g/cc — —
Temperature Range: -67°F to 392°F
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Material / Substrate | Solid Silicone | — |
| Color | Black | — |
| Specific Gravity | 1.08 g/cc | — |
| Thickness | 0.010″, 0.020″, 0.031″, 0.063″, 0.125″ | — |
Mechanical Properties
| Property | Value | Test Method |
| Durometer, Shore A | 20 | ASTM D2240 |
| Tensile Strength | 640 psi | ASTM D412 |
| Elongation | 580% | ASTM D412 |
| Tear Resistance | 116 ppi | ASTM D624 |
| Compression Set, 70 Hours @ 302°F @ 25% | <25% | ASTM D395 |
Thermal Properties
| Property | Value | Test Method |
| Temperature Range | -67°F to 392°F | — |
| Thermal Conductivity | 0.22 W/m·K | ASTM D518 |
Electrical Properties
| Property | Value | Test Method |
| Dielectric Strength | 374 Volts/mil | ASTM D149 |
| Dielectric Constant | 2.97 kHz | ASTM D150 |
| Dissipation Factor | 0.003 kHz | ASTM D495 |
| Dry Arc Resistance | 123 seconds | ASTM D495 |
| Volume Resistivity | 10^14 Ohm-cm | ASTM D257 |
Environmental Performance
| Property | Value | Test Method |
| Low Temperature Brittleness @ -80°F @ 3 Minutes | Pass | — |
| UV Resistance | Yes | ASTM D2137 |
| Ozone Resistance | Yes | — |
- Electronic enclosure and battery compartment seals requiring low closure force and high conformability
- Thermal and EMI/RFI shielding gaskets in electronics assemblies
- Shock and vibration damping components in medical, aerospace, automotive, and telecommunications equipment
- Precision die-cut gaskets where tight thickness tolerances and high tear resistance are critical
- General demanding gasketing in applications across a broad service temperature range
Common industries: Electronics, medical devices, aerospace, automotive, telecommunications.
BISCO® HT-6220 is a soft solid silicone at 20 Shore A, engineered for demanding gasketing in electronic enclosures, battery compartments, and applications requiring thermal and EMI/RFI shielding. Its low durometer enables a highly protective seal with minimal closure force, reducing the risk of damage to delicate housings while maintaining reliable sealing integrity.
The combination of 116 ppi tear resistance and extremely tight thickness tolerances supports consistent gasket performance in precision applications across medical, aerospace, automotive, and telecommunications industries.
The material provides 374 Volts/mil dielectric strength, 10^14 Ohm-cm volume resistivity, 123 seconds dry arc resistance, and a thermal conductivity of 0.22 W/m·K. It passes low temperature brittleness testing at -80°F for 3 minutes per ASTM D2137 and demonstrates UV and ozone resistance.
What differentiates BISCO® HT-6220 from firmer solid silicone grades?
BISCO® HT-6220 is rated at 20 Shore A — one of the softest Shore A solid silicone grades available — enabling a highly protective seal with less closure force than conventional medium-durometer grades. Its combination of 116 ppi tear resistance and extremely tight thickness tolerances provides gasket integrity in precision electronics and enclosure sealing applications where softer, more compliant materials are required.
Why is compression set an important consideration for solid silicone elastomers?
Compression set measures how well an elastomer recovers its original thickness after sustained compression. In sealing applications, a material with high compression set will permanently deform over time, reducing sealing force and allowing leak paths to develop. BISCO® HT-6220 achieves <25% compression set (70 hours @ 302°F @ 25% deflection per ASTM D395), supporting sustained sealing performance at elevated operating temperatures.
What is the temperature range for BISCO® HT-6220?
BISCO® HT-6220 is rated for service from -67°F to 392°F, as listed on the TDS.
Is BISCO® HT-6220 suitable for electronic sealing and EMI/RFI shielding applications?
Yes. The TDS lists dielectric strength of 374 Volts/mil, volume resistivity of 10^14 Ohm-cm, dry arc resistance of 123 seconds, and thermal conductivity of 0.22 W/m·K, supporting its use in electronic enclosure sealing and thermal/EMI shielding applications. No specific compliance standards are cited on the TDS.
How should BISCO® HT-6220 be specified?
Specify grade (BISCO® HT-6220), thickness, dimensional tolerances, and finished format.
