summary

PMMA, the chemical name is polymethyl methacrylate, commonly known as acrylic, acrylic (from English Acrylic) or plexiglass (because of the very good light transmission), the English name is Polymethyl methacrylate, referred to as PMMA; molecular formula-[CH2C(CH3 )(COOCH3)]n-; CAS number is 9011-14-7; it is polymerized by methyl methacrylate monomer MMA; has good transparency, chemical stability, weather resistance, easy dyeing, easy Processing, beautiful appearance and other characteristics, so it is widely used in construction, advertising, transportation, medicine, industry, lighting and other fields

Technology Overview

PMMA is formed by polymerization reaction of methyl methacrylate (MMA) under the action of crosslinking agent and catalyst. The basic chemical reaction formula is as follows:

In the early 1930s, the German ROHM Company (ROHM) successfully developed the bulk polymerization PMMA production technology and realized industrialized scale production.

In the 1960s, Resart-Ihm of Germany and Mitsubishi Rayon Co., Ltd. (MRC) of Japan successfully developed suspension polymerization and continuous bulk polymerization PMMA production technology, and realized industrialized production in the 1970s.

At the end of the 1970s, Resart-Ihm of Germany and KSH of the United States jointly invested and jointly developed solution polymerization PMMA production technology with Polymer Technology (PTI) of the United States. In the early 1980s, an industrial production facility was established in the United States. .

At the end of the 1980s, global MMA production increased rapidly, which promoted the scale and continuity of PMMA production. Due to the blockade of bulk polymerization technology, by the late 1990s, solution polymerization production technology had become the mainstream technology in the international market. Therefore, the current PMMA production technology mainly includes suspension polymerization, solution polymerization and bulk polymerization.

Suspension polymerization: The viscosity of the polymerization system is low, and the mass transfer and heat transfer are easy to control; the process flow is short, and the polymer solution only needs to undergo simple separation, washing, drying and other post-treatment processes to obtain resin products, which can be directly used for molding processing; The technology is mature, the equipment investment cost is low; but the production capacity is low, the product purity is poor (the residual bill and the ash content are high), large-scale continuous production cannot be carried out, and the sewage treatment volume is large. The figure below shows the suspension polymerization process flow chart

Solution polymerization: The viscosity of the polymerization system is low, the mass transfer and heat transfer are easy to control, and large-scale continuous production can be carried out without sewage treatment problems. However, because the polymerization system contains a large amount of solvents, the monomer concentration is low, the polymerization rate is slow, the utilization rate of equipment and the production capacity are low; the polymer solution needs to undergo post-treatment processes such as multi-stage flash evaporation and granulation to obtain the resin. Products; a large amount of solvents and unreacted monomers removed at the same time need to be rectified and purified, recycled and reused, post-processing energy consumption is high, and production costs are increased; the amount of additives is small, the product has less impurities, and the thermal stability is better. The following figure shows the process flow chart of solution polymerization

Bulk polymerization: the polymerization system does not contain solvents, the viscosity of the materials is large, the mass transfer and heat transfer control are relatively difficult, the requirements on the process and equipment are very strict, and the operation is relatively difficult; but the product is pure, high in transparency, and there is no sewage treatment problem. A small amount of unreacted monomer needs to be recovered, and the post-processing energy consumption is low. The following figure shows the flow chart of the bulk polymerization process

In the industrial production of PMMA, the suspension polymerization process is generally used for small-scale batch production, and solution polymerization and bulk polymerization processes are used for large-scale continuous production. The following figure shows the characteristics of the polymerization technology of 3 types of PMMA

Production status

In 2019, there are more than 300 domestic PMMA manufacturers with a total production capacity of about 800,000 tons/year. The main production companies include Zhenjiang Chimei, Nantong Liyang, Germany Evonik, Suzhou Shuangxiang, Wanhua Chemical, Lucite International, Heilongjiang Longxin, Huiling Chemical, Shanghai Jingqi, Ningbo Shenchun and Kuraray Zhangjiagang, etc. , The total production capacity is about 620,000 tons/year; in addition, there are many small-scale PMMA manufacturers in China, which are mainly distributed in East China, South China and other regions. The raw materials are cracked again into MMA, and then PMMA is produced. Due to restrictions on the quality of raw materials and technical levels, such products cannot be guaranteed in quality, cannot compete with foreign products, and can only be used in low-end markets. my country's cracking PMMA production capacity is about 180,000 tons/year.

The main manufacturers are located in Jiangsu, Shanghai, Zhejiang, Shandong in East China, Guangdong in South China, and Heilongjiang in Northeast China. There are no PMMA manufacturers in other parts of the country, mainly because PMMA's main raw material MMA is also distributed in East China and South China (specifically You can refer to "Methyl Methacrylate (MMA) Status and Future Trends"), and the economy of East China and South China is relatively active, and the main consumption area of PMMA is also here. Therefore, domestic PMMA production is mainly distributed in East China and South China.

Due to the late start of my country’s PMMA industry, wholly foreign-owned enterprises are my country’s main PMMA manufacturers, accounting for 50% of the market. If the capacity of PMMA manufacturers is not considered, the proportion of foreign companies will reach 65%. Therefore, domestic PMMA manufacturers There is still a lot of room for improvement, and the prospects are promising!

In 2019, China's PMMA production process is dominated by bulk polymerization, accounting for 52%. The bulk polymerization process is basically foreign-funded enterprises and newly constructed projects in the past two years; solution polymerization accounts for 25%, mainly Taiwan-funded enterprises and some domestic companies. Earlier construction projects used this process; in addition, it can be seen that the low-end technology for producing PMMA by cracking PMMA recycled materials and scraps still occupies a 23% share. It is believed that with industrial upgrading and stricter environmental protection, this part of the production capacity must be Will be replaced by advanced processes such as bulk polymerization

In 2019, domestic PMMA production is expected to reach 300,000 tons, an increase of 11% over 2018. With the increase in domestic PMMA production, the self-sufficiency rate is also continuously increasing, from 45% in 2010 to 60% in 2019

Overview of future trends

With the continuous development of my country's construction industry, decoration industry, transportation industry, etc., my country's market demand for PMMA-related products will continue to grow. Special PMMA products, such as radiation-proof PMMA, optical fibers and solar photovoltaic cells, are still blank, and PMMA, which is widely used in high-purity optical discs abroad, has just started in my country. With the development of the liquid crystal display manufacturing industry, the demand for light guide plate materials will increase, and the consumer market for optical PMMA is huge. Therefore, we expect the average annual growth rate of PMMA in the next few years to be 8-12%

At the same time, in the future, Shandong Qiheng New Materials, Dongming Huayi Yuhuang New Materials, and Suzhou Shuangxiang Optical Materials plan to build new PMMA projects, with an additional capacity of about 500,000 tons.