TPI Engineering Plastic Resin: Further Development Will Be Tough Going

By Fang Shengzhong, CAS Ningbo Institute of Industrial Technology

Two Chinese institutes developed thermoplastic polyimide (TPI) engineering plastic resin at an early date – CAS Changchun Institute of Applied Chemistry (M-200 series) and Shanghai Research Institute of Synthetic Resins (YS-30 series). More recently, some other organizations such as CAS Ningbo Institute of Industrial Technology and Nanjing Yuezi Chemical Co., Ltd. have also developed several types of TPI engineering plastic resin.
Most TPI producers in China are small scale and bear high costs. The selling price of TPI resin is over RMB1 000/kg. The total output is only several dozen tons a year. The volume of the civil market is quite small. Products are mainly supplied to enterprises related to national defense.

High-end manufacturing sectors promote the market demand

To maintain rapid development of the economy, China must be able to replace steel with plastics in high-end manufacturing sectors, including the aviation/spaceflight, automobile and electronic sectors. TPI is a special heat-resistant engineering plastic resin that can endure long-time use at a temperature of 250℃ or even 300℃. Therefore, in many cases, TPI is the only material that can be used in high-end manufacturing.
Global output of TPI resin has reached around 40 000 tons a year, with average annual growth around 10%. Industrialization of TPI engineering plastic resin in China is proceeding very slowly today. Consumption is around 2 000 tons a year, and almost totally depends on import.
In the Twelfth Five-Year (2011-2015) and Thirteenth Five-Year (2016-2020) development programs, TPI granules were regarded as an important resource product and raw material for the state. Raw materials of polyimide have been developed rapidly in China in recent years. Lots of raw materials for foreign polyimide material companies are imported from China. Also, some new polyimide material companies have appeared in China. Therefore, upgrading TPI industrialization here with timely industrial restructuring and independent intellectual property rights is essential.

Development of the sector has arduous tasks to fulfill and a long path to tread

Among low-end TPI engineering plastic resin varieties (the temperature for long-time use being lower than 220℃), Ultem resin of SABIC firmly holds the market in China due to super-high cost effectiveness and excellent workability and stability. China has not yet overcome the technical barriers to develop similar products with higher cost effectiveness.
For high-end TPI engineering plastic resin varieties (the temperature for long-time use being higher than 220℃), foreign companies have conducted overall technology blockade and product embargo to China.
As soon as the Specialty Polymer Material Team was founded in Ningbo Institute of Industrial Technology, it took the low-cost manufacturing of polyimide resin as the goal, relied on the long-term accumulation of isomerized polyimide basic research, regarded the molecular structure design and advanced production method of TPI resin as the breakthrough point, used chlorophthalic anhydride isomer mixture as raw material and PPS polyimide as the main target and initiated China’s research on low-cost manufacturing of polyimide engineering plastic resin. TPI resin with low cost, novel structure and excellent properties was finally developed.

The technology potentially has independent intellectual property rights. Four invention patents have already been applied for at home and abroad and one of them is an international patent. Polyimide resin produced with the technology has long-time heat resistance at 220℃, being 50℃ higher than Ultem. It offers high cost effectiveness and very strong market competitiveness. The project team then made further efforts and developed the second-generation TPI engineering plastic resin. Compared with the first-generation resin, differs in both formula and synthesis process. It offers better processing stability and better product properties. The project team applied for invention patent of the state and the patent is already granted.
It is hoped that large-scale production of low-cost TPI engineering plastic resin will be achieved in China in the next 3-5 years.