–Green and safe high-temperature cabling solutions for high-end equipment
In high-end fields such as aerospace, new energy, rail transportation, and semiconductor manufacturing, cables need to operate continuously at temperatures above 200°C while meeting stringent safety requirements for halogen-free, low-smoke, and low-toxicity (LSOH). Traditional halogen-containing flame-retardant materials (such as FEP and cross-linked polyolefins) release corrosive/toxic gases at high temperatures, while ordinary halogen-free materials (such as silicone and TPE) cannot withstand continuous high temperatures. PEEK (polyetheretherketone), with its intrinsic halogen-free flame retardancy and continuous temperature resistance up to 250°C, has become the only cable insulation/sheathing material that combines high-temperature stability, environmental safety, and high reliability.
I. Core performance advantages: Why is PEEK the only solution?
| Performance dimension | Require | PEEK performance | Compared with traditional materials |
| Long-term temperature resistance | ≥200℃ (continuous) | Stable operation at 250℃ (UL certified RTI 250℃) | Silicone (180℃) and XLPO (150℃) fail |
| Flame retardancy | Halogen-free, V-0, low smoke | UL94 V-0 (0.4mm) smoke density <50 (NBS) | Halogen-containing materials with a smoke density >300 release HBr/HCl |
| toxicity | Non-corrosive gases | Combustion products: CO₂ + H₂O (halogen-free, sulfur-free) | PVC releases hydrogen chloride, which corrodes equipment. |
| Mechanical strength | Vibration/bending resistance | Tensile strength 90–100 MPa, notched impact strength 15 kJ/m² | Silicone strength <10 MPa, easily torn. |
| life | ≥20,000 hours @ 200℃ | Accelerated aging extrapolates lifespan to >30 years | Silicone silicone at 200℃ has a lifespan of <5,000 hours. |
Key Mechanism:
PEEK molecules do not contain halogen, phosphorus, nitrogen and other flame retardant additives. Its flame retardancy comes from the high aromatic ring content (60%+) – when burning, a dense carbon layer is formed, which isolates oxygen and achieves intrinsic halogen-free self-extinguishing.
II. Typical Application Scenarios and Value Verification of TST CABLE Halogen-Free Flame-Retardant PEEK Cables with Temperatures Above 200℃
2.1 Aerospace (Highest safety level)
| Application areas | Operating conditions | PEEK value |
| Engine compartment sensor lines | 200–250℃ + Vibration | Halogen-free flame retardant to prevent fire from spreading to the oil system. |
| Cabin emergency system | FAA FAR 25.853 requirements | Smoke density <200, ensuring passenger escape visibility |
| Satellite power bus | GEO Orbit Deep Charging | Halogen-free gas emission rate <0.1%, anti-pollution optical payload |
✈️Application scenario :
“It is used in the insulation layer of high-voltage cables of Tiangong space station. It is resistant to aging, flame retardant, low smoke and low toxicity, and will not short circuit and catch fire due to radiation aging.”
2.2 New Energy Vehicles (800V High Voltage Platform)
| Application areas | Security challenges | PEEK scheme |
| High-voltage wires inside the battery pack | thermal runaway risk | Halogen-free flame retardant to prevent flames from spreading along the circuit. |
| Motor winding lead wire | 200℃+ High-frequency PWM | Corona resistant and halogen-free, preventing HF corrosion of copper wires. |
| Fast charging cable | Plug-in heating + fireproof | UL94 V-0, meets GB 38031-2020 standards. |
Case Study: A high-end electric vehicle uses PEEK high-voltage wires, which do not catch fire after passing a needle penetration test and have obtained EU WVTA certification.
2.3 Rail transport (EN 45545-2 HL3)
| Require | PEEK compliance status | Defects of traditional materials |
| RIS-312-CCP (Smoke Density) | <100 (actual measurement 50) | Halogenated materials >300 |
| RIS-313-CCP (Toxicity) | CO yield <50 g/kg | PVC HCl production >200 g/kg |
| Oxygen Index (LOI) | >35% | XLPO ≈ 28%, halogenated flame retardant needs to be added. |
Applications: Internal connection wires for high-speed rail traction converters, emergency power supply wires for subway batteries.
2.4 Semiconductors and Data Centers
| Scene | need | PEEK Advantages |
| Etching machine RF power cable | Ultra-clean + halogen-free | Metal ion concentration ≤1 ppb, no particulate pollution during combustion |
| AI Server Liquid Cooling System | 200℃ coolant environment | Fluoride-resistant and halogen-free, RoHS/REACH compliant |
| Hydrogen electrolyzer | High humidity + high pressure | Water absorption rate <0.3%, stable insulation |
III. Structural Design of PEEK Halogen-Free Flame-Retardant Cables
3.1 Key Performance Indicators of Typical Structures (Taking Aero-engine Line as an Example)
| Test Project | standard | Measured PEEK value | Require |
| UL94 flame retardant | UL 94 | V-0 (0.4mm) | V-0 |
| Smoke density (Dsₘₐₓ) | ASTM E662 | 45 | <200 (FAR 25.853) |
| Toxicity Index | NES 713 | <1.0 | <5.0 |
| thermal aging | UL 746B | Strength retention ≥70% after 3,000 hours at 250℃ | RTI 250℃ |
| Halogen-free certification | IEC 60754-2 | HCl < 0.1 mg/g | <5 mg/g |
Key points of the process:
No flame retardants added (maintaining intrinsic properties).
Ultra-high purity (avoiding catalytic degradation by impurities)
Laser welding termination (to avoid mechanical damage)
IV. International Certification and Standards Compliance
| field | standard | PEEK compliance |
| aviation | FAR 25.853 / CS 25.853 | ✅ Low smoke, non-toxic, V-0 |
| Rail transit | EN 45545-2 (HL3) | ✅ RIS-312/313 meets standards |
| New energy vehicles | GB 38031-2020 / UN GTR 20 | ✅ Halogen-free, thermal runaway protection |
| Electronics and Electrical | IEC 60695 / UL 746B | ✅ RTI 250℃ certified |
| Environmental friendly | RoHS / REACH / Halogen-free (IEC 61249-2-21) | ✅ Br<900ppm, Cl<900ppm |
Global Market Access: TST CABLE PI series has received UL Yellow Card certification (RTI 250℃).
V. Progress in Localization and Cost Optimization
5.1 Breakthrough in the industrial chain
| Link | Domestic representative | progress |
| Cable | TST CABLE, TST SEAL | Certified by C919 and high-speed rail |
5.2 Cost vs. Value
| Cost items | PEEK line | Silicone/XLPO wire | difference |
| Initial Procurement | 2.5x | 1.0x | +150% |
| Security compliance costs | Extremely low | High (requires additional fire prevention measures) | ↓30% |
| Failure risk | Almost zero | Medium-high temperature aging | Insurance costs ↓ |
| Total life cycle cost | 0.7x | 1.0x | ↓30% |
Economic inflection point: When the equipment safety level is SIL2+ or in densely populated areas, PEEK is the optimal solution.
VI. Implementation Recommendations and Selection Guidelines
6.1 Applicable Scenarios Determination
Operating temperature ≥200℃?
PEEK must be used
Is it a crowded/enclosed space?
PEEK is recommended (safety first).
Cost-sensitive?
Evaluation of silicone/TPE
PEEK enhances brand value.
6.2 Supplier Selection Checklist
✅ UL Yellow Card: Confirms RTI (Relative Thermal Index) of 250℃
✅ Halogen-free report: IEC 60754-2 test data (HCl < 0.1 mg/g)
✅ Smoke density test: ASTM E662 or NBS chamber report
✅ Industry certifications: such as AS22759 (aviation), EN 45545 (rail transit)
VII. Future Technology Directions
Nano-modified halogen-free PEEK:
Adding nano-clay → Smoke density ↓ to 30, flame retardancy ↑
Bio-based PEEK:
10% bio-based monomers → Reduce carbon footprint and meet ESG requirements
Intelligent flame retardancy:
Microencapsulation technology → High-temperature release of free radical scavengers, delaying combustion
Safety is the primary performance characteristic of high-temperature cables.
“Next to a flame at 200°C, the toxicity of a burning cable could determine life or death.”
The value of PEEK halogen-free flame-retardant cables lies not in cost, but in:
Life safety: low smoke and non-toxic, ensuring safety in confined spaces;
Equipment safety: no corrosive gases, protecting precision instruments
; Compliance safety: meeting the world’s strictest fire safety standards;
Strategic security: domestic production breaks the monopoly, supporting high-end manufacturing.
From the Tiangong space station to 800V supercharging stations,
from the Fuxing high-speed train to AI liquid-cooled servers,
PEEK is redefining the safety boundaries of high-temperature cables with its green commitment to low smoke and halogen-free operation and reliability up to 250℃ .
TST CABLE recommends:
Safety-critical systems: Mandatory use of PEEK halogen-free wiring
Exporting high-end equipment: Advance planning for UL/EN certification
Domestic substitution: TST CABLE custom development
True flame retardancy is not about adding chemicals, but about preserving the inherent dignity of the material itself.
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