Overview

PMMA, chemically known as polymethyl methacrylate, is commonly referred to as acrylic (derived from the English word "Acrylic") or organic glass (due to its excellent light transmittance). Its English name is Polymethyl methacrylate, often abbreviated as PMMA. Its molecular formula is [CH2C(CH3)(COOCH3)]n-, and its CAS number is 9011-14-7. It is produced by the polymerization of methyl methacrylate monomer MMA. PMMA boasts excellent transparency, chemical stability, weather resistance, ease of coloring, ease of processing, and an aesthetically pleasing appearance. As a result, it is widely used in fields such as construction, advertising, transportation, medicine, industry, and lighting.

Technical Overview

PMMA is formed through a polymerization reaction of methyl methacrylate (MMA) under the action of crosslinking agents, catalysts, and other additives. The basic chemical reaction equation is shown in the figure below:

In the early 1930s, the German company ROHM successfully developed an bulk polymerization technology for producing PMMA and achieved industrial-scale production.

In the 1960s, Resart-Ihm of Germany and Mitsubishi Rayon Co., Ltd. (MRC) of Japan successively developed successful technologies for the suspension polymerization and continuous bulk polymerization of PMMA, and achieved industrial-scale production in the 1970s.

In the late 1970s, Resart-Ihm of Germany and KSH of the United States jointly invested with Polymer Technology Inc. (PTI) of the United States to develop a solution-polymerization technology for producing PMMA. In the early 1980s, an industrial-scale production facility was established in the United States.

In the late 1980s, global MMA production increased rapidly, driving the scaling up and continuous operation of PMMA manufacturing. Due to the technological blockade on bulk polymerization, by the late 1990s, solution polymerization had become the dominant technology in the international market. Consequently, today, the main PMMA production technologies are suspension polymerization, solution polymerization, and bulk polymerization.

Suspension Polymerization: The polymerization system has low viscosity, making mass and heat transfer easy to control. The process flow is short, and the polymer solution requires only simple post-processing steps such as separation, washing, and drying to obtain the resin product, which can then be directly used for molding and processing. The technology is well-established, and equipment investment costs are relatively low. However, this process has lower production capacity, poorer product purity (high residual monomer and ash content), and is not suitable for large-scale continuous production; moreover, it generates a large volume of wastewater. The following figure shows the process flow diagram for suspension polymerization.

Solution Polymerization: The polymerization system has low viscosity, making mass and heat transfer easy to control. It allows for large-scale continuous production and avoids wastewater treatment issues. However, since the polymerization system contains a large amount of solvent and the monomer concentration is relatively low, the polymerization rate is slow, resulting in lower equipment utilization and production capacity. The polymer solution requires multi-stage flash evaporation, granulation, and other post-processing steps to obtain the final resin product. Moreover, the substantial amounts of solvent and unreacted monomers removed during these processes must be purified via distillation and then recycled for reuse, leading to high energy consumption in post-processing and increased production costs. This process uses small amounts of additives, yielding products with fewer impurities and better thermal stability. The following figure shows the process flow diagram for solution polymerization.

Bulk Polymerization: In this polymerization process, no solvent is used, resulting in high material viscosity. Mass and heat transfer control are relatively challenging, placing extremely stringent requirements on both the process and equipment, and making operation quite difficult. However, the resulting product is highly pure and exhibits excellent transparency, with no wastewater treatment issues. Only a small amount of unreacted monomer needs to be recovered, leading to low energy consumption during post-processing. The figure below shows the flow diagram of the bulk polymerization process.

In industrial production of PMMA, small-scale batch production typically relies on suspension polymerization, while large-scale continuous production predominantly employs solution polymerization and bulk polymerization processes. The figure below illustrates the characteristic features of these three PMMA polymerization technologies.

Production Status

In 2019, China had more than 300 domestic PMMA production enterprises, with a total production capacity of approximately 800,000 tons per year. The major producers include Zhenjiang Chimei, Nantong Liyang, Evonik from Germany, Suzhou Shuangxiang, Wanhua Chemical, Lucite International, Heilongjiang Longxin, Huiling Huacheng, Shanghai Jingqi, Ningbo Shenchun, and Koloray Zhangjiagang, among others, whose combined production capacity amounts to about 620,000 tons per year. In addition, China also has numerous small-scale manufacturers that produce PMMA via pyrolysis. These manufacturers are mainly located in regions such as East China and South China, and they recycle PMMA products, edge trimmings generated during PMMA production and processing, and headstock materials by re-pyrolyzing them into MMA, which is then used to produce PMMA again. Due to limitations in raw material quality and technological levels, these products cannot guarantee consistent quality and thus cannot compete with foreign counterparts; they can only be used in low-end markets. China's pyrolysis-based PMMA production capacity is approximately 180,000 tons per year.

The major manufacturers are located in East China—Jiangsu, Shanghai, Zhejiang, and Shandong—as well as in Guangdong in South China and Heilongjiang in Northeast China. There are no PMMA manufacturers in other regions of China, primarily because the key raw material for PMMA production, MMA, is also concentrated in East and South China (for details, see “Current Status and Future Trends of Methyl Methacrylate (MMA)”); moreover, East and South China boast relatively robust economies, and these regions are also the primary consumption areas for PMMA. Consequently, domestic PMMA production is mainly concentrated in East and South China.

Since China’s PMMA industry started relatively late, wholly foreign-owned enterprises are the primary PMMA producers in China, accounting for 50% of the market share. If we exclude the production capacity of cracking-based PMMA manufacturers, the share held by foreign companies would rise to 65%. Therefore, domestic PMMA producers still have considerable room for improvement, and the outlook is promising!

In 2019, the primary PMMA production process in China was bulk polymerization, accounting for 52%. The bulk polymerization process was mainly adopted by foreign-invested enterprises and newly established projects over the past two years. Solution polymerization accounted for 25%, primarily used by Taiwanese-funded enterprises and some older domestic projects. In addition, a low-end technology that recycles PMMA waste and edge trimmings via pyrolysis still accounted for 23% of the market share. We believe that as industrial upgrading progresses and environmental regulations become stricter, this segment of capacity will inevitably be replaced by more advanced processes such as bulk polymerization.

In 2019, China's PMMA production is expected to reach 300,000 tons, an increase of 11% over 2018. As domestic PMMA production rises, the self-sufficiency rate has also been steadily increasing—from 45% in 2010 to 60% in 2019.

Application Overview

As an excellent-performance transparent material, PMMA is widely used in various applications, including lamps and lighting fixtures, optical glass, dials and housings for a wide range of instruments and meters, scales, optical fibers, shop windows and billboards for commercial advertising, aircraft cockpit windows, bulletproof glass for airplanes and automobiles, and glass products for diverse purposes (medical, military, and architectural applications). In recent years, with the advent of 5G and advances in PMMA modification and composite material technologies, PMMA’s applications have expanded into areas such as mobile phone back covers, optical display materials, and plastic optical fibers. In particular, the rapid growth of the liquid crystal display (LCD) market has led to a substantial increase in demand for optical-grade PMMA molding compounds. The following figure illustrates the major consumption sectors of PMMA in China.

Overview of Future Trends

With the continued development of China’s construction industry, interior decoration and renovation sector, transportation industry, and other related sectors, the market demand for PMMA-related products in China will continue to grow. Specialty PMMA products—such as radiation-resistant PMMA, optical fibers, and solar photovoltaic cells—remain largely untapped, while high-purity PMMA used extensively in overseas for manufacturing high-quality optical discs is only just beginning to take off in China. As the liquid-crystal-display manufacturing industry continues to expand, it will drive increased demand for light-guiding plate materials, creating a huge consumer market for optical-grade PMMA. Therefore, we anticipate that in the coming years, the annual average growth rate of PMMA will be between 8% and 12%.

Meanwhile, in the future, Shandong Qiheng New Materials, Dongming Huayi Yuhuang New Materials, Suzhou Shuangxiang Optical Materials, and other companies plan to launch new PMMA projects, adding approximately 500,000 tons of new production capacity.