About polyoxymethylene

There are only two domestic manufacturers based on Chinese investment: Yuntianhua and Blue Star. Although the polyformaldehyde market is currently developing at a high speed, due to the limited new application fields, domestic production capacity expansion and price war will be the theme of the future.

The production process of polyformaldehyde is divided into two types, namely, homopolymer production process and copolymer production process. There are two sets of domestic copolymer formaldehyde production equipment using domestically developed technology. Due to shortcomings such as small production scale, high consumption of raw materials and public works, unstable product quality, and large emissions of "three wastes", the device has been discontinued for many years. In addition, a 10kt/a copolymer formaldehyde device with imported technology has been built in China and has been put into production. There are two production processes abroad: homopolymer and copolymerization. ； The homopolymer production process is represented by the process of DuPont Company in the United States. The process uses 50% formaldehyde aqueous solution as raw material, which is first reacted with higher alcohols to generate hemiacetal. The hemiacetal is dehydrated and thermally decomposed to obtain high-concentration formaldehyde gas, and then refined to obtain anhydrous formaldehyde for polymerization. Suspension polymerization of anhydrous formaldehyde is carried out in an inert solvent containing a catalyst, and then centrifugation, drying and other processes are performed to obtain a powdery crude polymer. The crude polymer is stabilized by esterification end-capping using acetic anhydride. The stabilized polymer is added with various additives, mixed evenly, and extruded for granulation to obtain finished polyformaldehyde pellets. The copolymer production process is represented by the process of Celanese Corporation of the United States. Formaldehyde is first concentrated, concentrated formaldehyde is synthesized into parformaldehyde under the action of a catalyst, and then refined parformaldehyde is obtained through processes such as concentration and distillation. Purified trimerformaldehyde and the second monomer dioxane undergo copolymerization reaction under the action of a catalyst. After the crude polymer is ground and passivated, various additives are added through post-processing, and then the finished copolymerized formaldehyde pellets are obtained through extrusion granulation. At present, companies with copolymer production technology include DuPont and Celanese in the United States, BASF in Western Europe, ZAT in Poland, Polaroid Corporation in Japan, Asahi Kasei Corporation, * * Fuyi International Engineering Company, etc. The production technologies of these companies are similar, but each has its own characteristics. Currently, companies that can transfer copolymer production technology to China include Polish ZAT Company and Fuyi International Engineering Company.

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I have a classmate at Shanghai Blue Star. In addition, there is a company called Baotailing in Nantong, Jiangsu, which also produces polyformaldehyde. This company is jointly funded by a Japanese company and Celanese.