Let’s talk about the polyoxymethylene project – how’s it going?

At present, a 40,000-ton facility of Xinjiang United Chemical is under construction； 20,000-ton Nantong (DuPont process) plant under construction ； Yuntianhua’s 20,000-ton facility is under construction ； At present, the Petrochemical Technology Development Center of Tianjin University has developed a polyoxymethylene production process with an annual capacity of 20,000 tons, drawing on the most advanced production technologies available abroad. This process utilizes techniques such as two-stage falling-film concentration, spray granulation, and continuous drying, thereby overcoming the shortcomings associated with domestic batch concentration methods and rake or scraper-type drying processes – namely limited production scale, high raw material consumption, and poor product quality. As a result, all quality and consumption metrics related to polyoxymethylene production have reached advanced international levels. Technical principle and process: A 37% or 55% aqueous formaldehyde solution is first depolymerized, and then a concentrated formaldehyde solution of around 80% is obtained through two-stage falling-film vacuum concentration. After a polymerization reaction takes place under the action of a copolymerization agent, the final polyformaldehyde product with a concentration of around 96% is produced via spray granulation and continuous drying. Consumption metrics per ton of product: 37% formaldehyde – 2.8 tons, steam – 3.0 tons, cooling water – 200 tons, electricity – 260 kwh. Production scale and output: 20,000 tons/year. Required floor area for the factory: 10,000 m2. Main equipment: depolymerization kettle, falling film evaporator, polymerization reactor, granulation tower, dryer, absorption tower, and cooler, etc.

I have a set of technical attachments related to Polish technology; if anyone is interested, we discussed it in 2001, but no contract was ultimately signed.

Yuntianhua currently has a production capacity of 30,000 tons (1+2). Polyoxymethylene (POM) is regarded as the \"metal among plastics\" due to its high technical barriers. The domestic market demand for POM is 200,000 tons per year, with an annual growth rate of 20%; yet in China, only Yuntianhua produces 30,000 tons and Toray of Japan produces 50,000 tons, while the rest must be imported. Yuntianhua invested 300 million yuan in the initial 10,000 tons of production capacity, and it was not until three years after operation that actual benefits were generated. The company plans to expand its production capacity to 90,000 tons by 2009, becoming the leader in the domestic market.

This is a summary of the polyoxymethylene projects I have collected, for your reference only. If there are any inaccuracies, please point them out; if there is any new information, feel free to add it. Thank you.

**Company production capacity (in 10,000 tons):**
Yuntianhua: Already has a production capacity of 30,000 tons thanks to its 3+6 facility; plans to build an additional 60,000 tons. The planned investment is 149,600 yuan, with 138,700 yuan allocated to construction. The project will be carried out in the Chongqing Changshou Industrial Park in three phases. The first phase, with a capacity of 20,000 tons, is scheduled to start operations in 2008, while the remaining two phases are set to begin operation in 2010.

This project is a joint venture between Japanese Boride Corporation, Mitsubishi Gas Chemical Company, and Ticona. With a total investment of 140 million US dollars, they established Baotailing Engineering Plastics (Nantong) Co., Ltd. in Nantong, Jiangsu Province, to build a production facility capable of producing 60,000 tons of polyoxymethylene per year. This facility began operating in October 2005.

Daqing Oilfield Methanol Plant: Construction was planned to be completed in 2005, but the project was put on hold due to the high cost of importing foreign technology.

Shanxi Lanhua Kechuang, **Huaming Group Co., Ltd., Taiwan’s Foxconn Technology Group, and Indonesia’s Golden Paper Industries (China) Investment Co., Ltd.:** A project with a capacity of 100,000 tons is planned to be built in Jincheng, Shanxi Province.

Lanxing Group: Has a 4+6 production capacity facility in the Shanghai Xinghuo Development Zone. The first phase, with a capacity of 40,000 tons, is scheduled to start operating by the end of 2007, while the second phase, with a capacity of 60,000 tons per year, has already begun construction and is expected to be completed by 2010, resulting in a total capacity of 200,000 tons.

DuPont and Japanese Asahi Kasei: Have a 2+4 production capacity facility in Zhangjiagang, Jiangsu Province. With an investment of 69 million US dollars, this facility produces copolymerized polyoxymethylene, and 20,000 tons of this product are already in production.

Xinjiang United Chemical: Construction has already started, with operations expected to begin in October 2008

Polyoxymethylene (POM) (1) Properties: Polyoxymethylene (POM) can be divided into two categories: one is the homopolymer of trioxymethane or formaldehyde, known as homopolymerized POM; the other is a copolymer of trioxymethane and a small amount of pentane ring, known as copolymerized POM. Polyoxymethylene is an important general-purpose thermoplastic engineering plastic, and its production capacity ranks third, behind polyamides and polycarbonates. Polyoxymethylene features a low relative density, good impact strength and dynamic fatigue strength, as well as excellent wear resistance, corrosion resistance, self-lubricating properties, and electrical properties; it also has low permeability to air and water vapor. (2) Applications: Products such as gears, buttons, water meters, valves, pump impellers, components for sprinklers, and zippers made of polyoxymethylene are widely used in industries such as automobiles, electronics and electrical equipment, industrial machinery, agriculture, and consumer goods. (3) Production methods: Polyoxymethylene production processes. There are 3 production methods for polyoxymethylene: using formaldehyde as a monomer, catalytic synthesis using trioxymethane as a monomer, and radiation polymerization using trioxymethane as a monomer. The first two of these processes have been industrialized. Currently, the production capacity of homopolymer POM accounts for only about 20% of the global POM production capacity; only DuPont and Japanese company Asahi Kasei produce homopolymer products, while the rest manufacture copolymer POM. DuPont uses a catalytic synthesis process with formaldehyde as the monomer. This process first removes water, methanol, and other impurities from formaldehyde, thereby producing highly pure formaldehyde through purification ； It is then introduced into an inert solution containing a cationic catalyst to polymerize into homopolyformaldehyde ； Then, the terminal hydroxyl groups are esterified and capped in the presence of the acylating agent acetic anhydride to obtain thermally stable POM; subsequently, additives such as antioxidants are added and granulation is carried out to yield the homopolymer formaldehyde product. DuPont’s homopolymerization process requires a very high purity of the raw material formaldehyde, necessitating the use of highly pure formaldehyde. Therefore, the content of impurities such as water and methanol in monomeric formaldehyde must be strictly controlled. Moreover, the capping treatment after polymerization is difficult, the process flow is long, there are many pieces of equipment, and corrosion is severe ； A large amount of nitrogen is required for protection during the drying and capping processes. Nippon Asahi Kasei uses a catalytic synthesis process based on polyoxymethylene as the monomer, and this homopolymerization process is more advanced than DuPont’s process. It consists of five steps: purification of paraformaldehyde monomer, continuous solution polymerization, continuous esterification for end-capping, extrusion granulation after venting, and solvent recovery. This process also utilizes the medium-concentration formaldehyde produced during the synthesis of triomethylenemethane; through reactive distillation, methylal is obtained, which is then oxidized to produce high-concentration formaldehyde. The characteristic of this process is the use of a solid catalyst other than sulfuric acid ； Polymerization is carried out using multi-stage short twin-screw reaction units ； The post-treatment process has also moved away from the wet hydrolysis approach. Production process of copolymerized formaldehyde: Copolymerized formaldehyde is produced by copolymerizing triformaldehyde as the main monomer with small amounts of other monomers such as dioxolane. The copolymerization processes mainly include solution polymerization and bulk polymerization. The solution polymerization method uses solvents such as gasoline, cyclohexane, or petroleum ether. Pure triomethylenemethane and dioxolane (used in an amount of about 2% to 5% of the triomethylenemethane) are placed in a reaction vessel, and at around 65°C, a boron trifluoride-ether complex in an amount of about 0.01% of the monomer amount is added. The polymerization is an exothermic reaction; the temperature inside the vessel is maintained at around 60°C for 1 to 2 hours. The reaction mixture is then transferred to a termination vessel, where a terminator is added to yield white powdery copolyomethylenemethane. After treatment with ammonia water, the final product is obtained. Products obtained by solution polymerization have good thermal stability. The bulk polymerization method involves mixing pure trioxane, dioxolane, and boron trifluoride-ether complex in certain proportions, then placing the mixture in a continuous kneader or twin-screw reactor that provides strong shear and mixing effects. After the polymerization reaction is complete, ammonia water is used for post-treatment to obtain granular copolyoxymethylene. The advantages of the bulk polymerization method are its simple process and easy operation; no solvent is used in the polymerization, the conversion rate is high, and the molecular weight distribution of the product is uniform. Therefore, currently, manufacturers at home and abroad generally use the bulk polymerization method. The continuous gas-phase copolymerization process developed by Nippon Yusen Kogyo is advanced and features significant advantages. The process involves: high-purity formaldehyde gas, along with copolymerized trioxane monomers and ethylene oxide, being used in the presence of a boron trifluoride-ether complex at temperatures of 40–70°C; a molecular weight regulator is then added to produce a specific type of copolymerized formaldehyde powder. This powder is subsequently treated with a stabilizing solution at temperatures of 130–160°C to remove any unstable end groups, thereby yielding a stabilized slurry. Finally, through steps such as filtration, drying, and granulation, the final copolymerized formaldehyde product is obtained. The POM production process at Shanghai Solvent Factory and Jishihua Shijinggou United Chemical Plant involves concentrating 37% industrial formaldehyde to 65% formaldehyde using a thin-film evaporator; thereafter, triomethylenetetrahydrofuran is produced under the catalysis of sulfuric acid, and finally this compound is refined to achieve a purity of 99.5%. Polymer-grade triomethylenemethane and dioxolane are polymerized in-situ in a twin-screw polymerization reactor; subsequent grinding, treatment with ammonia water in a kettle, drying, and mixing for granulation yield copolymerized methylene oxide granules. However, the difference between the two is that the Shanghai Solvent Factory uses dichloroethane for the extraction and purification of polyoxymethylene, while the Jishiheshigou Integrated Chemical Plant employs cold crystallization. At present, foreign manufacturers have advanced technology, their products offer excellent overall performance and high quality, and the prices are also low. In comparison, China’s POM manufacturers fall far behind in terms of process technology, plant capacity, and product quality. Therefore, given the strong upward trend in China’s demand for POM, companies should, while introducing advanced foreign technologies, accelerate the development of domestic POM technologies and build POM production facilities with capacities of over 10,000 tons, in order to reduce product costs and enhance their competitiveness. (4) Production status: In 2002, the world’s production capacity for polyoxymethylene was 845,000 tons, with the majority of this capacity located in developed countries such as the United States, Germany, Japan, and the Netherlands. Due to the high technical difficulties involved in its production, it is concentrated in the hands of a few manufacturers, most of which are directly or indirectly controlled by companies such as DuPont, Hoechst, Celanese, and Polyplastic. Hoechst and DuPont are the largest producers of polyoxymethylene in the world, with production capacities accounting for 28% and 24% of the global total respectively. The United States, Germany, the Netherlands, Japan, South Korea, as well as Taiwan Province of China, all have polyoxymethylene production facilities with a capacity of 10,000 tons each. In China, the development of polyoxymethylene began in 1959, with joint efforts by institutions such as the Changchun Institute of Applied Chemistry under the Chinese Academy of Sciences and the Shenyang Research Institute of Chemical Technology to develop both homopolymer and copolymer forms of polyoxymethylene. In 1970, the polyformaldehyde production facilities at Jilin Shijingou United Chemical Plant and Shanghai Solvent Factory came online. All use the triomethyleneperoxide route, and the production processes are roughly similar. However, after more than 30 years of development, no significant breakthroughs have been achieved in terms of technology, leaving a large gap compared to foreign companies; this is reflected in smaller plant scales, high material and energy consumption, low crystal quality, a limited range of product grades, and unstable product quality. In 1997, Yuntianhua Group Company introduced a polyoxymethylene production technology with an annual capacity of 10,000 tons from the Polish company ZAT, and the production facility was built in 2000. In 2003, the total domestic production capacity for polyoxymethylene reached 12,700 tons per year. Currently, the new and planned polyoxymethylene production facilities in China include: Daqing’s 20,000 t/a polyoxymethylene plant, and China Blue Star (Group) Corporation’s 20,000 t/a polyoxymethylene plant ； Japan’s Boride Plastics Co., Ltd., Mitsubishi Gas Chemical Company, and the U.S.-based Ticona Company have joined forces to build and put into operation a polyoxymethylene production facility with an annual capacity of 60,000 tons in Nantong City, Jiangsu Province ； DuPont (China) Group Co., Ltd. and the Japanese company Asahi Kasei will jointly establish a joint venture in Zhangjiagang, Jiangsu, to produce polyoxymethylene resin; the initial production capacity will be 20,000 tons per year, with this capacity to rise to 60,000 tons per year by 2005 ； Jointly invested by Dalian Wantai International Trade Co., Ltd., Dalian Ruilong Investment Group Co., Ltd., and Xinjiang United Chemical Co., Ltd., a 20,000 t/a polyoxymethylene plant is being constructed in the Kuqa Industrial Park in Xinjiang, taking advantage of the region’s abundant natural gas resources. By the end of this year, domestic production capacity for polyoxymethylene is expected to exceed 200,000 tons. (5) Consumption and demand: The global demand for polyoxymethylene was 650,000 tons in 2001, around 690,000 tons in 2002, and 740,000 tons in 2003. In the coming years, its consumption growth rate is estimated to be around 6% per year. It is expected to reach 1.1 million tons in 2010. Among all consumption areas, automobiles account for 30%, electronics and electrical appliances account for 20%, machinery accounts for 15%, daily necessities account for 15%, pipeline irrigation accounts for 10%, and others account for 10%. In 2003, China’s apparent consumption of polyoxymethylene reached 153,000 tons. In our country, the consumption of polyoxymethylene is mainly in industries such as home appliances, light industry, and machinery. Among them, electronics and home appliances account for 27%, light industry 23%, machinery 16%, automobiles 9%, and others 25%. With the rapid development of China’s electronics, home appliances, automotive, and equipment manufacturing industries, the application of polyoxymethylene is also increasing continuously. It is predicted that in 2010, the apparent domestic consumption of polyoxymethylene will reach 240,000 tons.

Add two new projects to be built: CNOOC Tianye Chemical with a capacity of 60,000 tons, and Tianjin Alkali Plant with a capacity of 40,000 tons

I have worked on some of the design aspects for this project for several companies, and in all cases it was a capacity of 30,000 tons per year

I’m interested in starting a homopolymer oxymethylene project with an annual production capacity of 30,000 tons. If anyone has the relevant technology, please get in touch – we can achieve a win-win situation!

If you want to obtain homopolymer methyl acrylate, I suggest you contact DuPont; however, the chances of it being available for transfer at the moment are basically 0. This post was last edited by feidian1100 on 2007-8-27 08:56

Is the production technology for polyoxymethylene mature in our country today? In recent years, Yuntianhua has introduced 10,000-ton polyoxymethylene production facilities from the Polish company ZAT; however, the technology involved is not very advanced. As a product characterized by high technology, high investment, and high output – the so-called \"three highs\" – polyoxymethylene requires sophisticated production techniques and generates substantial profits. It represents one of the key areas of interest for multinational companies. Since no breakthroughs have been achieved in China’s core technologies related to polyoxymethylene, foreign companies are reluctant to transfer such technology to China or establish joint ventures there.