Introduction to ET Sheath-Core Composite Fiber (PE/PET Composite)
ET sheath-core composite fiber is a bicomponent fiber prepared by a special spinning process, with polyethylene (PE) as the sheath layer and polyethylene terephthalate (PET) as the core layer, forming a “sheath-core” structure. This fiber combines the flexibility and chemical resistance of PE with the high strength and heat resistance of PET. By precisely controlling the ratio of the sheath to core layers (typically 20%-30% sheath and 70%-80% core), an optimized combination of properties is achieved. The fiber diameter generally ranges from 10 to 30 microns, featuring a uniform sheath-core structure, excellent wear resistance, bending fatigue resistance, and a smooth surface or specially adjusted texture through process modification.
Core Application Areas
- Textiles and Apparel
- Used in high-end sportswear fabrics, leveraging the hydrophobicity of the PE sheath layer and the moisture conductivity of the PET core layer to achieve a “waterproof outer layer, moisture-permeable inner layer” function, enhancing wearing comfort.
- Manufactures industrial textiles such as protective gloves and filtration materials (air dust filter cloth), utilizing PE’s acid-base corrosion resistance and PET’s high strength to extend service life.
- Nonwovens Industry
- Medical field: Applied in surgical gowns and disinfectant wipes, where PE’s low toxicity and PET’s stability meet hygiene standards, while the fibers can be heat-bonded into high-strength nonwovens through hot rolling.
- Packaging materials: Produces eco-friendly shopping bags and agricultural mulch films, with PE’s flexibility enabling easy processing and PET’s rigidity enhancing material stiffness.
- Composite Material Reinforcement
- Serves as a reinforcing fiber in resin-based composites (e.g., automotive interior parts, aerospace lightweight components). The sheath-core structure improves the interfacial adhesion between fibers and resin, enhancing the composite’s impact resistance and dimensional stability.
- Special Industrial Fields
- Fabricates sealing materials for high-temperature environments (e.g., oven door seals). The PET core layer’s heat resistance (melting point ~250°C) withstands moderate high temperatures, while the PE sheath layer provides the elasticity required for sealing.
Advantages Over PE/PP Composite Fibers
| Performance Dimension | ET Sheath-Core Composite Fiber (PE/PET) | PE/PP Composite Fiber |
|---|---|---|
| Heat Resistance | PET core layer has a high melting point (250°C), suitable for long-term use at 120-150°C, ideal for high-temperature processing or heat-resistant scenarios (e.g., hot rolling, drying). | PP core layer has a lower melting point (165-170°C), prone to deformation at high temperatures, limiting application scenarios. |
| Mechanical Strength | PET core layer offers tensile strength of 400-700 MPa, providing high overall fiber modulus and excellent tensile/tear resistance, suitable for high-strength applications (e.g., industrial lifting belts). | PP core layer has only 200-350 MPa tensile strength, with weaker fiber rigidity and prone to creep under long-term load. |
| Chemical Compatibility | PET core layer exhibits better resistance to organic solvents (e.g., alcohol, oils) and acid-base environments than PP, making it suitable for high-corrosion-resistance scenarios like medical and food contact applications. | PP core layer has poor resistance to polar solvents and is prone to swelling when exposed to oily substances. |
| Recyclability and Environmental Friendliness | PET is a recyclable material (recycling code 1), and both PET and PE are thermoplastics, enabling recycling through physical processes to meet environmental trends. | Although PP and PE are thermoplastics, PP/PE composite fibers are difficult to separate by flotation during recycling due to similar densities (both ≈0.9g/cm³), leading to higher recycling costs. |
| Functional Expansion | The PET core layer can be modified (e.g., by adding flame retardants or conductive carbon black) to endow fibers with antistatic, flame-retardant, and other special properties, suitable for electronic, fire-fighting, and other specialized fields. | PP core layer is more difficult to modify, limiting functional expansion. |
Conclusion
ET sheath-core composite fiber significantly outperforms traditional PE/PP composite fibers in heat resistance, strength, and environmental friendliness through the performance complementarity of PE and PET, making it particularly suitable for high-end markets with demanding performance requirements. With stricter environmental regulations and industrial upgrading needs, its application potential in sustainable textiles, high-performance composites, and other fields will be further unleashed.
