Development Status and Trend of Automotive Nonwovens in China

Chen Nanliang China's non-woven fabric used annually for the automotive industry, the number of nearly 70 million square meters, automotive non-woven fabric has accounted for two percent of the total domestic production of non-woven fabric, variety specifications of more than 130. Stitch non-woven cloth is very suitable for car decoration materials, vertical mesh non-woven fabric is mainly used for car sound insulation, and they are almost blank in the automotive applications in our country. Compared with textile fabrics (woven and knitted fabrics), non-woven materials easier to engineering design, in-depth molding, for a variety of interior parts complex surface shape requirements, according to the requirements of automotive manufacturers on the thickness of the material , Hardness and other indicators of personalized design. More than 40 kinds of non-woven parts used in automobiles are generally made of polyester, polypropylene, glass fiber, carbon fiber and some natural fibers through hydroentangling or spunbond, meltblown webbing Automotive structural parts, decorative parts and ancillary products, including air and oil filter media, interior materials, insulation materials such as insulation board. Increased use of automotive nonwovens Since nonwovens have been used in automotive interior applications, their superior properties have become increasingly recognized and, as research and development continue to deepen, nonwovens automotive interior materials have become functional The trend of diversification, in the car more and more widely used. It is understood that in 1997 an average car production of only 1 square meter of non-woven materials, and now a conservative estimate of each car needs more than 20 square meters of nonwovens (weight 15Kg ~ 20Kg), but the amount is still continuing to increase. The main purpose covers cushioning materials, covering materials, filter materials. According to Volkswagen's statistics, the annual use of automotive textile interior materials for golf cars alone has reached 100,000 to 150,000 square meters, most of which are non-woven materials, excluding non-woven materials such as fiber-reinforced plastic substrates and sound-absorbing materials. In recent years, China's non-woven fabric used in the automotive industry each year nearly 70 million square meters, automotive non-woven fabric has accounted for 20% of the total domestic production of non-woven fabrics, varieties and specifications of more than 130. In the field of automotive manufacturing, non-woven fabric to better meet the needs of different uses. The main reasons for the increasing application of nonwovens in the automotive field are as follows: firstly, the non-woven materials that can be engineered have the advantages over the woven ones; secondly, the products can be deeply molded and can be applied to any complicated surface of an interior part Shape requirements, according to the requirements of the car manufacturer on the thickness of the material, the hardness of personalized design. Third, due to the non-woven materials can be used in all parts of the car cabin, so it can achieve the same color and structural morphology, the use of liquid staining process, the product has better light and abrasion fastness, in addition, Nonwovens have a more balanced stretch property in both the machine and the machine direction than woven fabrics, so the appearance is more uniform after molding. Fourth, relative to its weight, non-woven materials can be designed to be stronger and extremely wear-resistant and heat-resistant. Fifth, nonwovens have a higher price / performance ratio and are lighter than woven materials, thus helping to improve the vehicle's fuel economy and thus make it more economical. Sixth, a variety of fibers can be combined in a non-woven material to achieve the best price / performance ratio. Seventh, non-woven sound-absorbing materials in the frequency range of 200 ~ 400Hz sound-absorbing effect than the standard reference material 5db, in the 400 ~ 1000Hz sound-absorbing effect is similar. Different uses of raw materials and market capacity Currently, the raw materials used to prepare non-woven fabrics for automotive interior parts are: polyester fiber, polypropylene fiber, glass fiber, carbon fiber, aramid fiber and natural fibers (such as recycled cotton fiber, linen , Hemp, jute and sisal fiber, etc.), of which polyester fiber and polypropylene fiber are the main ones. Foreign automotive interior materials in the development and research, such as the roof, door trim and rear cover, etc., emphasis on the use of natural fibers such as hemp. Nonwovens used for automobile production can be divided into molded interior parts (including roof, rear cover, door trim and headrests, molded carpets), sound absorbing / sound insulation and heat insulating materials (acoustic, heat insulating materials, Fluffy fiber-based pad can be molded) and composite and laminated materials (high performance fiber, natural fiber non-woven sheet, glass fiber nonwoven sheet and other) three categories. Because of its excellent extensibility, nonwovens are suitable for compression molding of car roofs and other components. They not only look good but also cost significantly less than other materials. General car roof covering material about 4.3m2, wagon is 7.3m2. Car roof usually used in the production process similar to the production of linoleum fabric, product weight is generally between 100 ~ 200g / m2, needle density 400 ~ 500 needles / cm2. There are three main types of automotive roofing nonwovens, one is through the acupuncture process stereotypes, and the other two were grams of 65g / m2 polyester hot-rolled non-woven fabric and specifications 25g / m2 of polypropylene filament nonwoven . The process is the above three kinds of non-woven fabric and car roof main body compound together, and then molded. With the development trend of lightweight automotive interior parts, non-woven fabric roof also to the direction of low weight development, such as the use of 100% polyester staple fibers prepared by the hot-rolled process quantitative 45g / m2 and 60g / m2 Of the roof material, which has high strength and high elongation physical indicators. Roof with non-woven fabric its price with the use of raw materials, grammage and processing methods and methods of post-processing there is a big difference between the weight of the car roof with a non-woven fabric is generally 60 ~ 80g / m2, the price 6 ~ 8 yuan / m2 between the specifications according to the actual requirements of choice. Automotive noise reduction materials should meet the following indicators as much as possible: First, lightweight is the development trend of the entire automotive manufacturing field, light weight material construction will not make the body weight increase too much, increase fuel consumption; the second is in the wide band range Sound insulation performance and sound-absorbing performance is good, noise performance and sound-absorbing performance long-term stability and reliability; third is a certain strength, easy to damage during installation and use, aging resistance, weather resistance and long life; Fourth, the appearance of neat, Pollution; moisture-proof, decay-proof moth, easy to mold; five is not easy to burn, with a certain degree of fire-retardant combustion-supporting performance; Six is ​​environmentally friendly, non-asbestos, glass fiber, lead and other heavy metal hazardous substances; , Stick firmly and so on. Sound absorption is one of the most important uses of automotive non-woven fabric materials. It is used in a large amount and is mainly used for roofs, floors, covers, fenders, dashboards, and hoods and air-conditioning ducts. In addition, high-class cars inside the door post and other spaces are filled as much as possible sound-absorbing materials to improve the overall mute effect of the car. In all parts of the car, most of the amount of sound-absorbing material is around the dashboard (high sound-absorbing requirements). At present, automotive noise-resistant non-woven fabric specifications are more common weight in the 500 ~ 2200g / m2, of which the amount of 500 ~ 800g / m2 majority, the general use of each car is about 3.5m2. According to statistics, in 2010, the output of China's passenger cars was 9.8384 million. Based on this, it is estimated conservatively that at present, the annual non-woven noise-proof materials in China will reach 34 million square meters. The main raw materials used for the product for a variety of waste fiber, then add some hot melt flour or melt processed, but the sound absorption, noise effect in general. Currently more used for middle and low sedans. Such products to be improved, can improve the sound-absorbing sound insulation performance, can expand the product applications. The trend of green renewable materials Dominant trend R & D trends are currently: the development of moldability, lightweight, thin non-woven ; To meet the needs of environmental protection and to develop "green" interior materials that save on energy, resources and recyclability, to develop single-material non-woven interior materials; to develop lightweight, better sound-absorbing and sound- Anti-staining, antibacterial, deodorant, aromatic, negative ion performance of functional non-woven interior materials. A notable trend in the development and research of foreign automotive interior parts is the emphasis on the use of hemp natural fibers in automotive interior structural materials such as roofs, door trim, and rear hatches. The use of natural fiber thermoplastic or thermosetting moldability (such as the door panels, etc.) has become a standard European sedan, each car used natural fiber up to 5 to 10 kg, as a new processing technology, "hemp natural fiber + Polypropylene injection molding technology "will continue to grow in the future. The reason why hemp natural fiber is used for growth in automotive molded interior parts is that it provides structural parts that are better ecologically and impact resistant and better toughness while helping to reduce the weight of the vehicle and improve the fuel economy of the vehicle. Microfiber structure enhancements Automotive interior with non-woven fabric filament hot-rolled cloth, needle-based substrate. At present, the amount of more is the spunbond and needle punched non-woven fabrics, other such as chemical bonding, thermal bonding, meltblown, stitch and other non-woven fabrics are also used, what method depends mainly on product function and cost Among them, 66% were spunbond, 27% were acupuncture, 6% were spunlace / resin bonded and 1% were other. The sound absorption of nonwovens can be enhanced by microfiber structures, such as ultra-fine synthetic fibers or natural fibers (eg cotton) and the like. Since around 2000, microfiber began to be used to produce lightweight, high performance sound absorbing materials. Microfiber can increase the specific surface area of ​​fiber, reduce the distance between the fiber and improve the viscous air friction resistance of air and fiber surface when the sound wave passes through the sound-absorbing material. In addition, the thermal insulation properties of the material can also be improved by reducing the convective diffusion of air inside the material. Sound-absorbing materials and insulation materials to use a similar structure, high-performance sound-absorbing materials can generally become a high-performance insulation material. Stitchwork and vertical webbing are still blank Spunlaced fibers are also used in the manufacture of nonwovens for car floor insulation, cushioning materials, and molding with other materials. It is a porous sound-absorbing material, the random distribution of fibers formed between numerous tortuous pores and connected to the surface, when the sound waves hit the nonwoven fabric, part of the energy is reflected, part of the energy into the gap, causing voids Of the air and waste fiber spinning small fibers, due to friction and viscous resistance, so that a considerable part of the sound energy into heat absorbed. Waste fiber is generally processed into a phenolic resin network with a density of 50 ~ 100Kg / m3, which uses the surface of self-adhesive sheet or coating for the roof, floor noise, shock absorption. When waste acoustic fiber nonwoven fabric is used to prepare sound-absorbing material and can bear self-weight, its weight is generally 100 ~ 250Kg / m3. Soft, elastic or dense, these nonwovens / mesh fins are molded to provide insulation on engine covers, car bodies and dashboards, and as linings for car floor tunnels, luggage and roofs. Also used in high-end vehicles are manufacturing techniques such as stitchbonding and vertical webbing (VLAP). Stitch nonwovens are well suited for automotive trim, whereas vertically woven nonwovens are predominantly used in automotive sound insulation, both of which are virtually blank in automotive applications in our country. Links Vertical Lining Nonwoven Technology Vertical Lining Nonwovens belong to a high loft fiber product. High-fluffy non-woven fabric is usually made by chemical bonding or thermal bonding. It has low cost and wide application. It is mainly used as filling material and sound insulation material.