Application Status And Development Trend Of Nonwoven Shoe Materials

　　 Application status and development trend of nonwoven shoe materials

Nonwoven technology has gained rapid development in a few decades because of its short process, high labor productivity, abundant raw materials and wide use of products. In terms of process characteristics, nonwoven fabrics are formed with very short procedures, high efficiency and high degree of automation. Processing methods are numerous, even Conghua spinning process can directly produce cloth, and the production speed is fast. At present, the highest speed can even reach 600 ~ 800m/min. Therefore, non-woven fabric has the unparalleled production capacity and speed and the cost advantage of unit area. The product structure is mostly made up of three-dimensional structure of single fiber, so it has the properties of microporous air permeability, excellent surface coverage, dimensional stability and gradient filtration. The unique technology and structural characteristics of nonwovens make it play a great advantage in shoe material production.

1 the status quo of nonwoven shoe materials

1.1 Nonwovens Artificial leather

With the rapid development of shoemaking industry, people have more and more requirements on shoe making materials and varieties. In addition to natural materials, the use of synthetic materials has been increasing in recent years. The use of synthetic materials made of nonwoven composite materials has developed rapidly. Artificial leather materials are mainly divided into synthetic leather and artificial leather. The application of nonwovens on shoe materials is mainly achieved through synthetic leather for shoes.

Synthetic leather has smooth surface, uniform material, no defects in natural leather, and designs all kinds of colors and patterns on the surface as desired. It provides great convenience for mechanical or artificial blanking, and its superior corrosion resistance and waterproof performance are superior to natural leather. Synthetic leather is closer to natural leather than artificial leather. It is an ideal substitute for natural leather at present. It is also a material that currently has the potential to replace natural leather. The disadvantage of synthetic leather is that it is not resistant to high temperature and high cold.

Synthetic leather is usually made of nonwovens and is coated with polyurethane on the surface. Among them, the choice of synthetic leather cloth plays a decisive role in the physical and mechanical properties, handle and processing performance of synthetic leather. The synthetic leather nonwovens used for shoes are often made of several different components, which are made up of a certain proportion of the process. They are made up of loosening, mixing, carding, airflow or mechanical net forming. The fibers are arranged in a disordered arrangement, then heated by steam, heat shrinkable and dipped in adhesive. The performance requirements of synthetic leather nonwovens for shoes are different from those of ordinary nonwovens. In terms of organizational structure, synthetic leather nonwovens must have a compact three-dimensional structure, fibers are arranged in a disorderly manner, interwoven and intertwined and distributed in three dimensions, so that the base cloth has the characteristics of breathability, moisture permeability, uniform structure and high strength. Secondly, in appearance and hand feel, the smooth surface of the base cloth is required. There is no longitudinal or oblique stitches and holes. The density of the base cloth should be uniform, no overdense or loose, and the fiber density should be uniform. High quality synthetic leather nonwovens are not allowed to have uneven cloud density under the condition of light transmission. In addition, in terms of performance, synthetic leather requires a high degree of anisotropy in the fiber mesh. In the classification of nonwovens, the needling method mainly produces thicker products, such as upper leather, etc. the spunlaced products are mainly suitable for medium and thin base cloth, such as shoe leather.

1.2 nonwoven shoe lining

Synthetic leather is mainly used as shoe upper material, and another important auxiliary material for shoe material is interlining. Because of the short process flow and low production cost, nonwovens gradually replace woven fabrics and become the main shoe lining materials. Among them, the air laid hot rolled nonwoven fabric has stronger strength, and the difference between transverse strength and longitudinal strength is small. Therefore, it is an ideal shoe lining material [4]. Other nonwovens, such as spunbonded nonwovens and spunlaced nonwovens, are also used as lining materials for shoes. These products are generally 80 to 150g/m2 in thickness and 0.5 to 0.55mm in thickness, with viscose / polyester 50/50, viscose / polyester 8O/20, nylon / polyester 50/50 as the main raw materials. Viscose fiber can improve the moisture absorption and softness of raw materials, while nylon can obviously improve its handle and elasticity [5]. In addition, nylon non-woven fabrics can also be used as lining materials for shoes. For example, the nylon nonwoven fabric lining material developed by ICI, UK, has excellent functions and characteristics due to dissimilar fiber materials and double clad structure (that is, a double layer fibrous structure of the same kind of polymer coated with another layer of polymer in the same core of the main polymer), and it also has excellent wettability, aeration and feel because of its two processing without resin. For example, the sweat absorption of ordinary cotton cloth is only 98% of its self weight, while the nylon nonwoven lining is 350% of its self weight, and it can be distributed and dried in 4 hours.

1.3 Nonwovens Insole

Another area of application of Nonwovens in shoe materials is shoe insoles. Generally, nonwoven insoles are mostly low-grade products, such as disposable nonwoven insoles and less high-grade products, which requires lighter weight, higher cushioning quality, excellent hygroscopicity and dispersivity, wear resistant and wearable surfaces and excellent shape retention. Such as polyester polyamide nonwovens developed by BUSM, UK, has good sweat absorption, good molding, moderate extensibility and beautiful appearance and rich color. It also has two functions, namely, shape protection and lining, and can be molded with uppers simultaneously by means of hot melt. In addition, because the material can be molded in a stretch state, it can also be used as a shoe head material to make it more beautiful.

2 development trend of nonwoven shoe materials

2.1 development direction of synthetic leather

With the continuous development of synthetic leather industry, the application of nonwovens base cloth is expanding. According to the requirements of high-grade synthetic leather products and the trend of domestic and foreign market, the future synthetic leather will require its base cloth soft, elastic, light weight, fashion sense, high density and good physical properties. At present, the density of synthetic leather bases in China is generally about 0.2g/cm3. For high-grade synthetic leather, the density of base cloth must be above 0.25g/cm3. Therefore, developing high-density synthetic leather base cloth is an important way to improve the grade of synthetic leather, and it is also a trend of the development of synthetic leather substrate. Among them, Fujian Nanfang Limited by Share Ltd nonwovens factory uses SK high shrinkage polyester as raw material, and adopts multi-channel needling technology. After heat shrinkable treatment and calendering, the synthetic leather base with high density and soft handle has been produced. After its products are put into the market, it has won favorable comments from users and has broad prospects for development.

In addition, with the development and application of sea island fiber and superfine leather, nonwoven simulation leather has developed rapidly and has become a new trend in the development of synthetic leather. Instead of leather, the nonwoven simulation leather can not only solve the problem of increasingly tight skin resources, but also avoid the disadvantages of low utilization rate, poor wear resistance, low tear strength, uneven texture and difficult cutting. The nonwoven simulation leather is a microfiber leather developed from island fiber and nonwoven technology. This kind of microfiber leather is a non-woven fabric made of island type microfiber material by loosening, carding and reinforcing needles to form a three-dimensional network structure. Then it is contracted and finalized, and then the polyurethane resin with different properties is immersed in different immersion ways. Then the solvent is used to dissolve the "sea" component of the sea island superfine fiber and the necessary alkali reduction is processed to form a fabric similar to the leather structure. Then, the superfine fiber products with different characteristics are made by chemical softness, rubbing, grinding, skin and dyeing processes. It is a multi-disciplinary product integrating spinning, nonwovens, chemical industry, leather, dyeing and finishing. The appearance, the handle and the inner structure of the product are all close to the real leather, and the physical properties are all over the dermis and widely used.

2.2 Functional Nonwovens

With the improvement of consumer consumption level, new requirements for shoe lining materials have been put forward. In order to cater for the needs of various sectors of consumption, the development of new products is mainly focused on comfort, health and hygiene. At the same time, in order to improve the added value of non-woven fabric shoes and meet the requirements of high-grade shoes brand, non-woven shoe materials with special functions have attracted increasing attention. For example, at present, the antibacterial products at home and abroad are very concerned. The antibacterial function nonwoven shoe material can not only keep the sanitary performance of the shoe cavity well, ensure the temperature and humidity of the shoe is certain, but also control the propagation of microorganism, reduce the chance of infection and reinfection of the foot skin disease, and eliminate the special odor of the shoes. Therefore, the application of antibacterial materials and the antibacterial function of non-woven materials by antibacterial finishing can speed up the penetration of Nonwovens in the application field of shoe materials, further expand the space for the market of nonwoven materials, and have a great market prospect. At present, the main antibacterial agents are three chloro, BIS guanidine antibacterial agents, quaternary ammonium salts, quaternary ammonium salts of organo silane and so on. Different antibacterial agents have different methods of finishing and suitable fiber products. The main methods of antibacterial finishing are to use the methods of rolling, coating, spraying, foam impregnation, and so on, combined with the specific processing technology of nonwovens, so that the antibacterial agent can be bonded to non-woven products, so as to obtain antibacterial non-woven fabric shoes.

2.3 Application of new Nonwovens Technology in shoe material manufacture

In order to further reduce costs and improve the application of Nonwovens Technology to shoe materials to meet the requirements of modern consumers for more styles and more fashionable footwear, new non-woven production processes and combination with other new production technologies need to be continuously developed. This is another development trend of Nonwovens in shoe making.

Among them, composite technology It is a new type of nonwoven technology developed in recent years. The technology combines mechanical or chemical methods to combine two or more than two kinds of materials. Due to the superposition of various single product functions, the product has excellent performance and gives the product functionality, applicability and widens its application area. At present, composite technology mainly includes: (1) jet jet mesh composite technology; jet jet mesh composite mainly uses high pressure water flow to spray all kinds of materials, through the puncture force of high pressure micro water flow and the resilience of the mesh support to the high-pressure water flow, so that all kinds of material fibers are entangled at the interface to form an integrated technology. (2) hot-melt viscose composite technology, which is mainly composed of two or more than two kinds of materials coated with hot melt adhesive through bonding. (3) all kinds of weaving technology and consolidation technology of nonwovens are interwoven and interpenetrated. Such as needle punching, chemical bonding, hot rolling, hot air bonding, melt blowing, stitching, spinning, mesh forming, jet net spraying and so on, and the combination of duplication technology, such as stacking, composite, molding, ultrasonic or high-frequency welding. Composite technology has made the products more colorful. It has become the latest trend in the development of nonwoven technology, and has produced a series of technological achievements that can make the nonwoven materials renew.