Low-melting fibers are the core materials of thermofusible yarn. Polymers such as TPU (Thermoplastic Polyurethane), PA (Polyamide/Nylon), and low-melting PET (modified Polyethylene Terephthalate) differ in chemical structure and performance, leading to variations in application scenarios, processing conditions, and final product properties. Below is a detailed comparison:
1. Material Properties Comparison
| Property | TPU | PA | Low-Melting PET |
|---|---|---|---|
| Melting Range | 80–130°C | 130–180°C | 110–160°C |
| Mechanical Properties | High elasticity, softness, abrasion resistance, flexibility | High strength, rigidity, heat resistance, wear resistance | Moderate rigidity, chemical resistance, low elasticity |
| Chemical Resistance | Resistant to oils/solvents; degraded by strong acids/bases | Good oil resistance; performance declines with moisture absorption | Excellent acid/alkali and detergent resistance |
| Moisture Absorption | Low (<1%) | High (e.g., PA6: ~3.5%) | Extremely low (<0.4%) |
| Processing Temperature | Low (100–150°C) | Medium-high (150–200°C) | Medium (120–170°C) |
| Sustainability | Recyclable; some bio-based variants | Recyclable but slow to degrade | Recyclable (conventional PET); poor biodegradability |
2. Processing Performance
TPU:
Advantages: Low-temperature melting, ideal for hot pressing, ultrasonic welding, and complex bonding; strong fluidity and elasticity.
Challenges: Requires precise temperature control (decomposes at high temps); slower cooling to avoid deformation.
PA:
Advantages: Retains strength at high temperatures; strong melt adhesion.
Challenges: High energy consumption due to elevated processing temps; moisture absorption affects stability.
PET:
Advantages: Cost-effective, wide processing window (extended melting range), excellent chemical resistance.
Challenges: Poor fluidity and rigidity; prone to brittleness after melting.
3. Key Applications
| Material | Applications | Example Products |
|---|---|---|
| TPU | Flexible and elastic requirements | Sports shoe midsoles, medical bandages, smart wearable composites, elastic textiles |
| PA | High-temperature and high-strength industrial uses | Automotive interiors (seats, headliners), fire-resistant gear, aerospace composites |
| PET | Cost-sensitive, chemically resistant daily goods | Diapers/sanitary products, disposable medical sheets, packaging laminates |
4. Selection Guidelines
Choose TPU for:
Elastic recovery needs (e.g., sports gear).
Low-temperature processing to protect heat-sensitive materials (e.g., foam).
Skin-contact products requiring softness and biocompatibility (e.g., medical textiles).
Choose PA for:
High-temperature environments (e.g., automotive engine components).
High mechanical strength (e.g., industrial conveyor belts).
Oil resistance (e.g., automotive carpets).
Choose PET for:
High-volume, low-cost production (e.g., disposable hygiene products).
Chemical-resistant industrial textiles (e.g., filters).
Rigid structural support (e.g., shoe insoles).
5. Innovations & Trends
TPU: Bio-based TPU (e.g., castor oil-derived) for sustainability; light/heat dual-responsive TPU for smart textiles.
PA: Low-moisture variants (e.g., PA12) for stability; nanocomposite PA for enhanced heat resistance.
PET: Biodegradable blends (e.g., PLA/PET); low-temperature PET for improved fluidity in precision bonding.
