Preparation Methods for Low-Melting-Point Hot-Fusible Nylon Filament

Preparation Methods for Low-Melting-Point Hot-Fusible Nylon Filament: A Technical and Application Guide

In the fiercely competitive global textile market, low-melting-point hot-fusible nylon filament is gradually becoming a focus of industry attention due to its unique properties and broad application prospects. This article will delve into the preparation methods of low-melting-point hot-fusible nylon filament, including its process flow, key technical points, quality control, and market applications, aiming to provide a comprehensive reference for global wholesale buyers and manufacturers.

1. Definition and Characteristics of Low-Melting-Point Hot-Fusible Nylon Filament
Low-melting-point hot-fusible nylon filament is a special type of nylon fiber with a low melting point (typically between 90°C and 130°C) while maintaining the high strength and abrasion resistance of nylon fibers. When heated to a certain temperature, this fiber softens and melts, becoming a viscous fluid with a certain degree of fluidity. Upon cooling, it resolidifies into a solid. This characteristic makes it widely applicable in textile processing, particularly in thermal bonding and composite materials.

2. Preparation Process of Low-Melting-Point Hot-Melt Nylon Filament
(I) Preparation of Nylon Chips
Nylon chips are the basic raw material for preparing low-melting-point hot-melt nylon filament. To ensure fiber quality and performance, nylon chips require rigorous drying. Vacuum drum drying is typically used, with drying temperatures controlled between 50°C and 70°C for 12 to 20 hours. The moisture content of the dried nylon chips should be less than 0.03% to prevent hydrolysis during the spinning process.
(II) Spinning Process
Spinning is the core step in the preparation of low-melting-point hot-melt nylon filament. The spinning process typically uses melt spinning, where the dried nylon chips are heated and melted in a screw extruder before being extruded through a spinneret to form fibers. Temperature control is crucial during the spinning process. The screw zone temperature is typically between 180°C and 225°C, while the spinning chamber temperature is between 200°C and 235°C. Furthermore, the spinning speed is generally controlled between 500 and 800 meters per minute. (3) Stretching and Shaping
Stretching is a key step in improving fiber strength and stability. During stretching, the temperature of the hot platen is controlled between 45°C and 55°C, and the setting temperature of the hot platen is between 55°C and 65°C. The stretch ratio is typically between 3.2 and 3.6. A suitable stretching process can significantly improve fiber strength and dimensional stability.
(4) Winding and Post-Processing
Winding is the process of winding the stretched fiber onto a reel. To ensure fiber winding quality, overfeeding is typically used, with an overfeed of between 2% and 5%. Post-processing includes oiling and shaping to improve the fiber’s antistatic properties and abrasion resistance.

3. Quality Control and Testing
Quality control of low-melting-point hot-melt nylon filament is implemented throughout the entire production process. From drying the nylon chips to winding the final product, rigorous quality testing is required at every stage. Key test indicators include fiber breaking strength, linear density, melting point, and thermal bond strength. Precise testing and control ensure the stability and consistency of product quality.

4. Market Applications and Prospects
Due to its unique properties, low-melting-point hot-melt nylon filament has broad application prospects in a variety of fields. It is primarily used in thermal bonding applications such as flyknit shoe uppers, socks and shoes, webbing, chenille, threaded connectors, lace, bonded yarn weaving, wool carpets, cushioning, and automotive interior linings. It can also be used in the manufacture of air-through shoe uppers, yarn manufacturing, and apparel manufacturing.
With increasing global attention to environmental protection and sustainable development, the market demand for low-melting-point hot-melt nylon filament is expected to continue to grow. Its low melting point and high bond strength make it an ideal environmentally friendly bonding material. In the future, with continued technological advancements and expanding application areas, low-melting-point hot-melt nylon filament is expected to play a significant role in even more fields.

5. Conclusion
The preparation of low-melting-point hot-melt nylon filament is a complex and delicate process involving multiple steps and stringent technical requirements. By optimizing process parameters and maintaining strict quality control, high-quality low-melting-point hot-melt nylon filament can be produced. This fiber is becoming an important product in the textile market due to its unique properties and broad application prospects. With the continuous advancement of technology and the growth of market demand, low-melting-point hot-melt nylon filament is expected to play a greater role in the future and contribute to the development of the global textile industry.