Drive the green transformation and upgrading of the textile industry - leading a "cloth" and "weaving" for a low-carbon future

"When I buy clothes recently, I find that more and more Chinese clothing brands have labels that say they are made of recycled fibers, and some also state the 'carbon footprint' of the clothes." Ms. Liu, a resident of Chaoyang District, Beijing, attaches great importance to environmental protection in her daily life, and she very much recognizes a new idea: a truly beautiful dress should not only be beautiful in appearance, but also "beautiful in origin" - the production process of clothing should be as low carbon and environmental protection as possible.

With the "double carbon" goal, the concept of green development has been deeply rooted in people's hearts. Like Ms. Liu, many people have begun to pay more attention to the low-carbon changes in the "food, clothing, housing and transportation" around them.

Today, the textile industry related to "clothing" is making great strides toward green transformation and upgrading. From waterless dyeing technology that can greatly reduce water pollution, to recycled fibers made of waste plastic bottles and waste clothing, and then to carbon fiber materials with excellent performance, innovative technologies have led the textile industry into a new stage of green and low-carbon development.

Say no to water pollution in textile industry

In the past, a large number of textile printing and dyeing enterprises gathered in Shantou, Guangdong province, which troubled the people living in the Lianjiang River basin: the chaotic discharge of various kinds of sewage not only gave off odor, but also polluted the soil in the surrounding villages. In recent years, Chaonan District and Chaoyang District of Shantou City have successively built textile printing and dyeing environmental protection comprehensive treatment centers, driving the transformation and upgrading of local textile printing and dyeing enterprises, and making Lianjiang appear clear.

For areas with textile industry as the main industry, water pollution is a problem that must be solved.

"The traditional textile industry is a typical industry with high energy consumption, high water consumption and high pollution, especially in the dyeing and finishing process of textiles, which will produce a lot of wastewater and waste residue." Cao Hongmei, vice president of textile College of Jiangsu Changzhou Textile and Garment Vocational and Technical College, told reporters that printing and dyeing wastewater contains dyes, slurries, additives, oils, fiber impurities and inorganic salts, high content of organic pollutants, large alkaline, water quality changes and high chroma, pollution treatment is difficult. Therefore, in order to fundamentally solve the water pollution caused by textile printing and dyeing, not only must the relevant departments strictly manage the discharge, but also rely on the continuous upgrading of printing and dyeing technology.

"The research and development of waterless dyeing technology is to reduce the production of printing and dyeing wastewater from the source." According to Cao Hongmei, the core of the current domestic research and development of anhydrous dyeing technology is the selection of non-aqueous media for dyeing. "Such as supercritical carbon dioxide dyeing technology, through pressurization, carbon dioxide liquefaction into a fluid medium, in this state after the completion of dyeing and then decompression, carbon dioxide can be recovered, the whole process does not need to wash, does not produce waste water." The other is to use organic solvents instead of water as a medium for dyeing, and after dyeing, the organic solvents can also be recycled."

These water-free dyeing techniques have been applied in practical production. Shandong Qingdao Jifa Group Co., Ltd. has industrialized the supercritical carbon dioxide dyeing technology and established a supercritical carbon dioxide anhydrous dyeing industrialization demonstration line, which has shortened the textile dyeing efficiency from 8 to 12 hours of traditional water dyeing to 3 to 4 hours. Guangdong Yida Textile Co., Ltd. uses organic solvent dyeing technology, in the dyeing process, saving water 100%, reduce energy consumption 39.3%, dye fixation rate of more than 97%, solvent recovery rate of more than 99%.

Not only can the process of "dyeing" save water, but also the washing link after dyeing has also changed due to the emergence of new technologies.

Jiangsu Lianyungang Yingyou Xinlicheng Textile Technology Co., Ltd. developed the flash dyeing no-wash process, "steam instead of washing", to achieve continuous, rapid dyeing and color fixing no-wash processing.

"General fabric dyeing after the need for washing steps, one is to wash away a large number of dyes in the dispersant, suspension agent, flexibility agent, thickener and other additives, the second is to wash away the floating color. So we developed dyes with almost no additives, which dramatically reduced the use of water." Sun Sumei, vice chairman of Jiangsu Lianyungang Yingyou XinLicheng Textile Technology Co., LTD., told reporters that in the flash dyeing production line, when the cloth passes through the pad dyeing unit, it is instantly colored under the action of 200 ° C high temperature, compared with the traditional process, it is removed from the four processes of washing, dehydration, fabric management, drying and setting.

"At present, the flash wash process is mainly applicable to polyester fabrics; The word "flash" in the process name mainly emphasizes the significant increase in production efficiency and production speed." Sun Sumei introduced that in order to calculate the production capacity of a single equipment, the traditional dyeing cylinder equipment can produce 4 tons per day, and the flash dyeing production line can produce 25 tons per day. "The flash dyeing process has been industrialized, and the company has four production lines with a daily output of more than 100 tons of cloth. At the same time, our production costs have also been greatly reduced, in the past to achieve such a output of at least 400 workers, now only more than 100 people. From the perspective of environmental protection, the chemical oxygen demand per ton of wastewater was as high as two or three thousand, and now only in the cleaning machine, the treatment of dark cloth needs to use some water, the water consumption is greatly reduced, the chemical oxygen demand value is also reduced to several hundred, it is easier to deal with, and the pollution is smaller."

Turn an old bottle into an old dress

What can an old plastic bottle do? If it is carelessly thrown away, it is polluting the environment. But if recycled, it could be turned into a piece of clothing, a fluffy toy, or a set of car interiors.

In Zhejiang Ningbo Dafa Chemical Fiber Co., LTD., there are tens of billions of waste plastic bottles a year into treasure. "We use waste textiles and waste drinking water bottles as the initial raw materials, after sorting, cleaning, drying, melting, spinning and other ten processes, the annual production of high-performance recycled polyester staple fiber 250,000 tons." Qian Jun, general manager of the company, told reporters that these polyester short fibers can be used as interior upholstery, sound-absorbing filter materials, as well as internal fillings for sofas and bedding, achieving a win-win situation of economic and social benefits.

Nowadays, the transformation of plastic bottles into chemical fibers in the textile industry is not a rare thing, and the wide application of efficient preparation technology of recycled polyester fibers has promoted the development of the textile industry in the direction of green, low-carbon and recyclable.

According to Qian Jun, the raw material for the production of recycled polyester staple fiber is polyethylene terephthalate (PET). The degradation of polyester in the natural environment is usually more than 50 years, and it is easy to cause environmental pollution. At the same time, polyester comes from petrochemical resources, and every 1 ton of PET waste is equivalent to saving 6 tons of oil resources and reducing 3.2 tons of carbon dioxide emissions. "At present, the stock of waste polyester products in China has exceeded 200 million tons, but its comprehensive recycling rate is still less than 15%, so the development of recycled polyester fiber industry is of great significance to protect the environment and develop circular economy."

In addition to waste plastic bottles, the recycling of waste textiles is also a major direction for the green development of the textile industry.

Zhejiang Beauty New Materials Co., Ltd. is an enterprise that helps "old clothes reborn". Recycled waste textiles, clothing factory scraps and other initial raw materials, are first sorted, ground, and then through chemical decomposition technology, degraded into small-molecule polyester materials, and finally through rectification, filtration, purification and polymerization means, re-made into new high-quality, multi-functional, traceable polyester fibers.

"The recycled fibers produced by the company have entered the high-end fabric market and are widely used in high-end sports, outdoor, fashion, home textiles and other fields, building a closed cycle from waste textiles to recycled new materials." According to the relevant person in charge of Zhejiang Beauty New Materials Co., LTD., in recent years, the company has handled 40,000 tons of waste textiles each year, and has an annual output of 30,000 tons of recycled products.

In March this year, the National Development and Reform Commission, the Ministry of Commerce, the Ministry of Industry and Information Technology jointly issued the "Implementation Opinions on Accelerating the recycling of waste Textiles", which proposed that by 2025, the recycling system of waste textiles will be initially established, the recycling capacity will be greatly improved, and the recycling rate of waste textiles will reach 25%. The output of recycled fibers from waste textiles reached 2 million tons. By 2030, a more complete recycling system of waste textiles will be built, the awareness of recycling among producers and consumers will be significantly improved, the ways of high-value utilization will continue to expand, the level of industrial development will be significantly improved, the recycling rate of waste textiles will reach 30%, and the output of recycled fibers of waste textiles will reach 3 million tons.

"In the future, the demand for recycled fiber raw materials will grow rapidly." Sun Huaibin, vice president of the China Textile Industry Federation, said that due to the constraints of the recycling system, sorting methods, technology and standards, the current domestic recycled fiber raw materials are mainly PET bottle pieces and industrial textile waste, the number of old clothes and fabrics from urban and rural residents is small, and the overall efficiency of waste textile recycling is low. "Next, we should speed up the change of waste textile sorting methods based on traditional manual identification, research and development of relevant sorting, opening, recycling equipment, etc., in order to improve the recycling rate of waste textiles and the output of recycled fibers, build a waste textile resource recycling system, and promote the development of related industries." Taking the recycling of waste textiles as a breakthrough will also help improve the entire recycling system of waste materials and improve the level of resource recycling." Sun Huaibin said.

Carbon fiber helps save energy and reduce emissions

Last year, the seventh generation of the 200 km/h maglev train made by CRRC was officially unveiled. It has a very special technical highlight: the body material is not the familiar aluminum alloy, but carbon fiber composite material.

The textile industry, which is gradually moving toward high-end, intelligent and green, can not only weave cloth, but also weave "everything". In addition to familiar clothing and home textiles, China has also made many innovations in industrial textiles, providing new possibilities for promoting the realization of the "double carbon" goal - carbon fiber is a typical representative of them.

Carbon fiber refers to the carbon content of more than 90% of high strength and high modulus fiber, with extremely high composite strength and high temperature resistance properties, can be used in aerospace, rail transit and other fields, replacing traditional metal products, thereby reducing the weight of equipment, reduce braking energy consumption, energy saving and emission reduction effect.

Taking the seventh generation of 200 km/h maglev train as an example, the use of carbon fiber composite materials has reduced its weight by 30% and increased its passenger capacity by 20%. Not only high strength, fatigue resistance, corrosion resistance, long service life, lighter body also reduces the operation energy consumption, more energy saving and environmental protection.

"In the field of new energy, carbon fiber, as a new lightweight material, also has a huge space to play." According to Yan Bing, vice president of Jiangsu Jiqi Carbon Fiber and Composite Materials Application Technology Research Institute, carbon fiber can be used in wind power, photovoltaic and other new energy equipment, such as making wind power blade girder, carbon carbon composite crucible for photovoltaic; It can also produce parts such as hydrogen storage bottles and battery electrodes for hydrogen energy vehicles. "It can be said that carbon fiber is essential to promote the realization of the two-carbon goal."

At present, Jilin Chemical Fiber Group is the largest carbon fiber production enterprise in China, with an annual capacity of 60,000 tons of carbon fiber and 25,000 tons of carbon fiber. The product specifications cover many varieties of large and small tow. In Jilin City, Jilin Province, there are 19 carbon fiber R & D and production enterprises, and more than 10 kinds of end products in 4 series of carbon fiber downstream products have achieved large-scale production, located in the carbon fiber industrial base in the economic development zone of Jilin City, and identified by the Ministry of Science and Technology as "national carbon fiber high-tech industrialization base".

Carbon fiber industry development has also received support from the local government. In September 2021, Jilin Province issued the "Several Measures to Promote the High-quality Development of Carbon Fiber and Composite Materials Industry", which formulated 19 specific policy measures from five aspects: optimizing spatial layout, highlighting innovation leadership, strengthening chain construction and chain reinforcement, ensuring factor supply, and strengthening policy support.

Jiangsu Province also has a good carbon fiber industry foundation, has cultivated a number of carbon fiber enterprises such as Zhongfu Shenying, Jiangsu Hengshen, and has a relatively complete upstream and downstream industry chain.

Taking Changzhou, Jiangsu Province as an example, up to now, Changzhou National High-Tech Zone has 45 enterprises associated with the carbon fiber and composite materials industry chain, and the sales revenue of enterprises in the carbon fiber and composite materials industry chain reaches 15 billion yuan in 2021. In recent years, the local carbon fiber and composite material industry has developed in the direction of scale, clustering and internationalization, forming the whole industrial chain ecology of carbon fiber raw fiber, carbon fiber, fabric, resin, prepreg, composite material products, key equipment and inspection and testing.

Yan Bing pointed out that after the development in recent years, China's carbon fiber technology has gone through the stage of "from scratch to existence", stride into the development track of "from there to excellent, stable quality and efficiency", but overall, the space for technological development is still very large, and there is still a gap with the world's leading level. "Carbon fiber technology is an extremely complex technical system, from the quality of raw materials, to the various processes of raw silk and carbonization, a lot of basic research and process and equipment research and development are required." In the future, domestic carbon fiber should continue to enhance the industry's research and development and innovation capabilities."

Cao Hongmei also said: "At present, China has entered the textile power from the textile power. From the perspective of technology and application, the overall level is in the world's advanced level, and individual technologies are leading the world. Specific to the lightweight application of high-performance carbon fiber, we also need to further strengthen research and increase the coverage of terminal promotion applications." She believes that in the process of green transformation of the textile industry, we should always pay attention to school-enterprise cooperation and the transformation of technological achievements. Especially for small textile enterprises, it is very important to work hard in the aspects of specialization, refinement, peculiarity, and novelization. With the help of the talents and intellectual resources of scientific research institutes in universities and colleges, they can concentrate on technological innovation, exert the characteristics and advantages of the subdivided fields to the extreme, and achieve green transformation and upgrading.