PAN-based pre-oxidized fiber, also known as oxidized PAN fiber, is a high-performance fiber material produced from polyacrylonitrile (PAN) precursor through a controlled oxidation process. During manufacturing, the PAN precursor is thermally stabilized within a temperature range of 200–300°C in an oxidizing environment. This process reorganizes and densifies the molecular chains of the fiber, forming a gradually stabilized ladder-like ordered structure.
PAN-based pre-oxidized fiber offers high strength, high specific modulus, abrasion resistance, heat resistance, chemical resistance, and electrical insulation. One of its most notable characteristics is its excellent thermal stability—when exposed to heat or flame, the fiber does not melt or ignite.
In addition, the fiber demonstrates excellent textile processability and can be used in spinning, weaving, knitting, and sewing processes.
It is widely used as a heat-resistant and flame-retardant material, including building insulation materials, fireproof insulation materials, and high-temperature furnace insulation. It is also used in protective textiles such as thermal protective clothing, firefighting suits, and fire blankets. Furthermore, it can be applied in automotive engine compartments and energy storage batteries as flame-retardant thermal insulation materials.
The production of 12K oxidized PAN fiber is a critical step in the carbon fiber manufacturing process, with the core process being thermal stabilization.
The raw material used is PAN-based precursor fiber.
The PAN precursor fiber is heat-treated in air within a temperature range of approximately 200–300°C. During this stage, the linear molecular chains of PAN undergo cyclization and oxidation reactions, forming a dense and thermally stable ladder structure.
After stabilization, the 12K filament tow is wound into spools or bobbins, forming the final product for convenient transportation and downstream processing.
| Parameter | Typical Value / Range | Notes |
|---|---|---|
| Fiber Tow Size | 12K | Each tow contains 12,000 individual filaments |
| Single Filament Fineness | ~1.32 dtex | Indicates the fineness of each filament |
| Limiting Oxygen Index (LOI) | >45% (typical) 35–55% (application range) |
Higher LOI means better flame resistance. >45% indicates extremely high flame retardancy |
| Density | ~1.4 g/cm³ | Slightly higher than common textile fibers |
| Color | Black | Characteristic color after oxidation |
| Thermal Stability | Excellent | Non-melting and non-flammable, forms stable carbonized layer |
| Chemical Resistance | Good | Resistant to acids, alkalis and organic solvents |
| Electrical Conductivity | Nearly non-conductive | Excellent electrical insulation |
| Processability | Good | Suitable for spinning, weaving, needling and sewing |
