Published May 2015
Polyimide and imide polymer resins are high-temperature-resistant polymers. This report covers imide polymers of commercial interest, including thermoplastic and thermosetting resins. Examples of thermoplastic polyimides include polyetherimides (PEI), polyamide-imides (PAI), and polyester imides (PESI), while thermosetting types are bismaleimides and PMR-15. A number of other products are commercially known by their trademarks (e.g., DuPonts Kapton® and Vespel®, Mitsui Chemicals Aurum®, and Evoniks P84® and Compimide®).
All of these polymers have excellent electrical and physical properties in addition to their high thermal and oxidative stability. Because of this combination of properties, these polyimides are used in aerospace, electronics, and various other industrial applications. "Pure" polyimide resins (without alternating ester, amide, or ether linkages) are high-temperature-resistant polymers that retain a significant portion of their physical properties in short-term exposures at temperatures exceeding 500°C. Other polymers that contain imide linkages have thermal resistances over a wide range of temperatures of at least 200°C.
The following pie chart shows consumption of polyimides and other imide polymers by major region:
Automotive, aircraft/aerospace (particularly new commercial aircraft), and food service markets will help drive consumption of polyimides and imide polymers as companies require products with properties such as higher service temperatures (i.e., increased thermal performance), greater toughness and flexibility, easier processing, and lighter weight (for fuel efficiency) at a reduced cost. It is estimated that global consumption rose at about 10% per year during 2009-14. The highest-volume polyimide is believed to be Sabics Ultem® polyetherimide.
The major US markets for polyimide molded parts are in bearings, bushings, seals, thrust washers, and valve seats for applications in jet engines, photocopying machines, computer printers, air compressors, and steam turbines. Polyimide molded parts compete for use with traditional materials such as ceramics and stainless steel. Ceramics are more expensive, heavy, and breakable. Stainless steel has poor aesthetics and is more expensive.
In Europe, the market for polyimides is dominated by wire enamels, where polyimides are used heavily in the automotive industry for wire insulation and electromagnet windings in E-engine cars. The market is expected to grow somewhat as there will be greater use of E-engines in middle and upper class cars and as European auto production continues to grow. Growth is forecast at 2% per year through 2019. The next-largest market is molding resins, dominated by Ultem®.
In Asia, the focus is more on electronics markets, where polyimide films are used to make flexible printed circuits for mobile devices, digital cameras, hard disks, and other electronics. Polyimide films are also used as wire insulation for generators and motors. Transparent polyimide films are of interest, as consumers want to replace glass with organic films to make flexible, lighter-weight flat panel displays, imaging sensors, solar cells, and other products.
In China, wire enamels and films and castings account for the bulk of demand. Use in wire enamels is expected to grow as demand for high-performance wire and cable will come from the booming growth of the Chinese high speed rail network, city expansions, new energy plants, and communication industries across China. Polyimide film and castings are used in power and electrical insulation, flexible printed circuit substrates, high-temperature wire and cable wrappings for motors, new-generation flexible liquid crystal display/organic light-emitting diode (LCD/OLED) displays, and advanced battery membranes. China has been increasing production of some polyimides, but largely remains an importer of high-end products.