In the past decade, China's non woven industry has developed rapidly, and has become the world's largest producer and trader of nonwovens. Demand driven production capacity growth has also promoted the innovation and development of nonwoven technology. At present, China's technological innovation achievements in spinning and melting production lines, two-component spunbonded Spunlaced microfiber non woven and other products have reached the international leading level. This paper introduces the development status of the key production process of non woven fabric and the gap between it and foreign technology.
Melt spinning technology is the most widely used technology in China's nonwoven industry, and its output accounts for nearly half of the total output of non woven. However, compared with the international advanced level, there is still a large gap in the domestic technical level. In recent years, the two-component and multi-component composite spunbonded method has become the main direction of the development of advanced technology. Developed countries have been able to produce various products with two-component composite spinning fiber cross-section structure, and have made breakthroughs in three component and four component fiber technology. Although China has developed hot-rolled and Spunlaced products of two-component composite spunbonded method, the large-scale two-component production line basically needs to be introduced from abroad, and the development still needs to learn from foreign technology and use licensed patented products.
Flash spinning process is the "top process" of non woven technology. Its spinning speed is very high and the amount of spinning solvent is less (compared with dry and wet); The fiber produced by this process has the advantages of high strength and light weight, and its diameter is 400~1000nm. At present, DuPont is the only company in the world that has mastered this technology and product industrialization ability, "Tyvek" is the trade name of its products. Affected by foreign patent protection system, domestic flash spinning technology has been in the exploratory stage. In the textile colleges and universities represented by Tianjin University of technology, and some equipment manufacturing enterprises have carried out some research and industrialization exploration in this regard, and have also made some phased achievements in small-scale test process technology and equipment, but there is still a long way to go before the application of industrialization. Only a few enterprises and personnel have conducted in-depth research on the key step of the flash process - the selection of the main solvent in the solvent preparation for flash spinning.
Cellulose mesh is widely used in biomedical field because of its biodegradation and biocompatibility. As early as the late 1960s, great progress has been made abroad in the cellulose fiber spinning and netting process represented by Lyocell's melt / melt blown netting technology. Lenzing company is a typical representative and technology leader in this field. At present, China has a complete set of Lyocell fiber national production equipment, process, safety, automatic control and engineering technology system, with the technical capacity of engineering design, engineering implementation and rapid industrialization promotion. In 2018, the Chinese Academy of Textile Sciences successfully developed a large-scale integrated technology and equipment for film evaporation, continuous dissolution and defoaming, as well as dry jet wet spinning technology and equipment for high viscoelastic spinning stock solution, and NMMO solvent low-temperature evaporation, concentration and recovery technology and complete equipment. At present, a Lyocell fiber production line with an annual output of 15000 tons has been built, and the related non woven products have been applied in the fields of clothing, home textiles, industrial textiles and so on.
With the market potential of fine denier non woven products getting more and more attention from the industry, spunbonded process, flash process and melt blown process will continue to develop in the direction of fiber fine denier and fine denier; The development of nonwoven products towards differentiation, functionalization and high added value urges enterprises to pay more attention to the combination innovation between different processes, increase functionality while improving spinnability, enhancing practicality and reducing production costs, and carry out technological innovation according to the needs of non woven fabric in different application fields and its own characteristics.