A number of mandatory national standards will be implemented soon

On November 13, the Ministry of industry and information technology issued eight compulsory national standards for the chemical industry, including the limit of harmful substances in wood coatings. The new national standard will put forward higher requirements for VOCs emission of polyurethane coatings, adhesives and other industries. At the fifth scientific research and technology exchange conference of waterborne polyurethane hosted by China Polyurethane Industry Association and organized by water based materials special committee and Oskar materials technology (Shanghai) Co., Ltd. on November 13-15, experts in the industry believed that with the continuous improvement of environmental protection requirements such as VOCs emission, waterborne polyurethane materials will welcome Dongfeng coating online coatingol.com. According to Wang wusheng, Professor of Anhui University, at present, the proportion of waterborne polyurethane in polyurethane industry in China is very small. In 2018, the output of polyurethane in China is about 11 million tons (equivalent to pure solid content), and the output of waterborne polyurethane is about 100000 tons, including 30000 tons of pure solid content. However, waterborne polyurethane is a very important product.

In recent years, due to the improvement of environmental protection requirements and awareness, China's waterborne polyurethane industry has developed rapidly, with the growth rate far exceeding the overall polyurethane industry. From the initial leather coating to textile coating, synthetic leather slurry, wood coating, industrial coating, automobile coating, polyurethane condom, the application field of waterborne polyurethane has been expanding and the technical level has been continuously improving. The environmental protection supervision has opened up a new development space for water-borne polyurethane materials. In order to implement the notice of the State Council on printing and distributing the three-year action plan to win the blue sky defense war, Shasha, project director of VOCs of the environmental engineering assessment center of the Ministry of ecological environment, said that the comprehensive treatment plan of VOCs in key industries issued by the Ministry of ecological environment in July this year clearly proposed to strengthen the comprehensive treatment of VOCs in industrial coating. We need to strengthen source control and accelerate the use of water-based and other low VOCs content coatings instead of solvent based coatings, including coatings for automobile manufacturing, steel containers, wood furniture, engineering machinery, electronic products manufacturing, and water-based adhesives for upholstered furniture.

The reporter noted that in the announcement of 8 compulsory national standards for the chemical industry issued by the Ministry of industry and information technology, 5 standards, namely, the limit of volatile organic compounds in adhesives, the limit of harmful substances in industrial protective coatings, the limit of harmful substances in building wall coatings, the limit of harmful substances in wood coatings and the limit of harmful substances in vehicle coatings, are all related to polyurethane Related to ester industry. "These mandatory standards are not far from being formally implemented. These measures are also intended to further limit VOCs emissions in the chemical industry, and will also bring new development opportunities to polyurethane waterborne materials. " Han Baole, Deputy Secretary General of China Polyurethane Industry Association, said. Cui Yanjun, deputy director of the special committee for waterborne materials of Polyurethane Association, said that there are many kinds of waterborne polyurethane products, including adhesives, coatings and leather resins. With the introduction of mandatory standards, a number of enterprises will face transformation and upgrading. Taking coating enterprises as an example, it is estimated that 70% - 80% of the enterprises can meet the new national standard to be implemented, and 20% - 30% of the enterprises are not up to the standard, so they must meet the policy requirements through environmental protection upgrading such as water-based. There are still many technical bottlenecks in the development of waterborne polyurethane. Zhang Haoming, vice president of China Polyurethane Industry Association, director of water property special committee and chairman of osga materials technology (Shanghai) Co., Ltd., thinks that solvent is still used in most of the production processes of water-based polyurethane dispersion at present, resulting in the problem of solvent recycling. How to reduce the amount of organic solvent and realize the green production without solvent through the research and development of new synthesis process and raw materials is an important research topic in the development of waterborne polyurethane materials. In the synthesis process of waterborne polyurethane, solvents are used to help dissolve reactants, reduce the viscosity of prepolymer and help dispersion. The synthesis of waterborne polyurethane requires high performance of solvent. The solvent must be inert and miscible with water. It has good dissolving ability for reactants and products, and its boiling point should be within a certain range.

At present, acetone and other solvents are needed in the synthesis of waterborne polyurethane, which are inflammable and explosive dangerous goods, and are limited in the process of production and transportation, so it is urgent to develop new non-toxic and safe solvents. " Wang wusheng explained. Wang wusheng also pointed out that although the VOCs emission in the application process of waterborne polyurethane is low, it will often produce more waste gas and waste residue in the synthesis and use process than solvent products. How to reduce the discharge of "three wastes" is also an important issue in front of the waterborne polyurethane industry. It is understood that among the four water-based resins (epoxy, acrylic, alkyd and polyurethane), polyurethane performance has certain advantages, but the application proportion is still low. As a matter of fact, the research on waterborne polyurethane materials in China has a long time and many good technologies. At present, the main problem is the lack of high-end raw materials. For example, the high-end curing agent, special polyol and other raw materials required for water-based materials, due to the high technical threshold, many of them are foreign patented technology, which restricts the development of the industry. The downstream application market is very large, so it develops very fast, but at present, it lacks Chinese brands. Most of our polyurethane brands are upstream. "