Silicone Heat Shrink Tube
1. Performance Indicators
| Property | Specification | Test Standard |
|---|
| Thermal Recovery | Shrink ratio: 2:1 / 3:1 / 4:1 • Recovery temp: 90°C–200°C | ASTM D2671 |
| Dielectric Strength | ≥25 kV/mm (post-shrinkage) • Arc resistance: ≥180 sec | IEC 60243 |
| Temperature Range | -70°C to +260°C continuous • Peak: +300°C (short-term) | UL 224 |
| Flame Resistance | VW-1 rated • Self-extinguishing ≤30 sec • LOI: ≥32% | UL 224 / IEC 60695 |
| Environmental Sealing | Water ingress: 0% @ 1m/24h • Salt spray: 1,000 hrs resistance | ISO 9227 |
| Chemical Resistance | Resistant to fuels, oils, solvents (IP 6K/6K2 tested) | ISO 1817 |
| Mechanical Protection | Abrasion resistance: ≥5,000 cycles (1kg load) | ASTM D3389 |
| Adhesive Liner | Melt-flow sealant: >85% cavity fill (optional) | NASA-STD-6001 |
2. Technical Parameters
| Parameter | Range | Tolerance |
|---|
| Material Composition | Radiation-crosslinked LSR + silica reinforcement | - |
| Hardness (Shore A) | 50A–80A (±5A) | ISO 7619-1 |
| Pre-Shrink Diameter | 1.0 mm – 150 mm | ±0.15 mm (≤20mm) / ±1% (>20mm) |
| Wall Thickness | 0.5 mm – 5.0 mm (post-shrink) | ±10% |
| Recovery Rate | ≥70% @ 150°C/5min | ASTM D2671 |
| Color Options | Red • White • Black • Translucent • Custom | Pantone/RAL |
| Special Features | • Flame-retardant additives • EMI shielding (nickel/copper coated) • Stress-cone geometry | - |
| Certifications | UL 224 • RoHS III • REACH • MIL-DTL-23053/5 | - |
3. Technical Data Sheet
| Characteristic | Value | Unit |
|---|
| Tensile Strength | ≥8.0 | MPa (ISO 37) |
| Elongation at Break | ≥400 | % |
| Volume Resistivity | ≥10¹⁴ | Ω·cm (IEC 60093) |
| Dielectric Constant | 2.9 – 3.3 | @ 1 MHz (IEC 60250) |
| Dissipation Factor | ≤0.004 | @ 1 MHz |
| Thermal Conductivity | 0.18 – 0.25 | W/m·K (ASTM D7984) |
| Compression Set (22h @ 200°C) | ≤25 | % |
4. Critical Applications
| Industry | Application | Technical Requirement |
|---|
| Electric Vehicles | • HV cable joints (600V–1000V) • Battery busbar insulation • Charging gun sealing | UL 224 • LV 214-2 flame test |
| Aerospace | • Engine wire harnessing • Radar component sealing • Thermal protection for hydraulics | MIL-DTL-23053/5 • EN 6059 flammability |
| Industrial Electronics | • Motor lead insulation • PCB component sealing • Sensor weatherproofing | IP68/IP69K • UL 94 V-0 |
| Renewable Energy | • Solar junction box sealing • Wind turbine pitch control wiring • Battery stack isolation | IEC 62930 • UV resistance >10 yrs |
| Medical Devices | • MRI coil encapsulation • Surgical tool insulation • Implantable device packaging | ISO 10993-5 • USP Class VI |
5. Performance Comparison
| Feature | Silicone Heat-Shrink | Fluoropolymer Heat-Shrink | PVC Heat-Shrink |
|---|
| Temp Range | -70°C to +260°C | -65°C to +200°C | -40°C to +110°C |
| Flexibility | Retains flexibility after 500 thermal cycles | Becomes brittle at low temps | Hardens over time |
| Chemical Res. | Resists fuels, sterilants | Excellent chemical resistance | Degrades with oils/solvents |
| Flame Rating | VW-1 (no halogens) | VW-0 (may contain halogens) | HB only |
| Dielectric Str. | ≥25 kV/mm | ≥20 kV/mm | ≤15 kV/mm |
6. Compliance & Certifications
- Electrical Safety: UL 224 • CSA C22.2 No 198.1 • IEC 60684-3
- Automotive: LV 214-2 (flame) • ISO 6722 (temp) • GMW 3191 (sealing)
- Aerospace: MIL-DTL-23053/5 • AS23053 • Airbus AIMS 04-08-001
- Medical: ISO 13485 • USP Class VI • FDA 21 CFR 177.2600
- Environmental: RoHS III • REACH SVHC-free • Halogen-free (<900 ppm Cl/Br)
Operational Guidelines
⚠️ Critical Limitations:
- Max shrinkage force: 1.5 MPa (reinforced grades support ≤4 MPa)
- Avoid sharp bends during install: Min bend radius = 3× recovered diameter
- Do not exceed 300°C during recovery (risk of silicone degradation)
Installation Protocol:
- Preparation: Clean substrate with IPA (<100 ppm particles)
- Heating Equipment: Hot air gun (≤400°C) • IR oven • Induction tools
- Recovery Process:
- Axial shrinkage: ≤10%
- Uniform heating rate: 3°C–5°C/second
- Hold at recovery temp for 60–90 seconds
- Adhesive Activation: For lined tubes – maintain 120°C–150°C for 2 min after shrinkage
Customization Options:
- Conductive Grades: Carbon-loaded (10²–10⁵ Ω/sq) for EMI shielding
- High-Voltage: >30 kV/mm with silicone/EPDM hybrid formulation
- Tri-Layer Designs:
Outer: Abrasion-resistant silicone
Middle: Fiberglass braid reinforcement
Inner: Meltable adhesive/sealant - Traceability: Laser-etched alphanumeric coding per IATF 16949
For specialized environments (>300°C, high-radiation, or cryogenic), request Aerospace/Medical Grade formulations certified to NASA-STD-6001 or ESA ECSS-Q-70-71.
