PAI plastic - Polyamide imide

PAI material is an amorphous thermoplastic high performance polymer, which is characterised, among other things, by high temperature resistance, good chemical resistance and excellent wear properties at temperatures of up to 275 °C. PAI plastic, also known under the brand name Torlon®, is one of the world's highest performance thermoplastics for melt processing.

Finished parts made of the Torlon® material have good mechanical load-bearing capacity due to high tensile and compressive strength. In addition, the PAI polymer offers high toughness and stiffness. The mechanical stiffness in combination with the low thermal expansion and the high temperature resistance contribute to the production of dimensionally stable finished parts. Other advantageous properties of the Torlon® material are its high tensile and compressive strength. 

Modifications of Torlon® PAI are also possible. By adding glass or carbon fibres, the strength and stiffness can be increased. If PTFE or other lubricants are added as an additive, friction is reduced and the sliding properties are increased, even with dry friction. 

PAI plastic absorbs moisture, which leads to dimensional changes in components. The material is sensitive to saturated steam at high temperatures. Overall, PAI polymer offers balanced mechanical, electrical, chemical, thermal and tribological properties and proves itself in demanding applications under difficult environmental conditions at high temperatures.  

Torlon® PAI is a registered trademark of the Solvay Group.


Ensinger processes PAI polymer by compression molding, injection molding and extrusion (under development). 

We produce PAI stock shapes in the form of PAI plates (Torlon® sheets), PAI rods (Torlon® rods) and PAI tubes (Torlon® tubes). Ensinger also processes the stock shapes into PAI finished parts in-house in our PAI machining department (Torlon® machining).  


PAI shape materials
Ensinger produces PAI polyamide imide stock shapes under the brand name TECAPAI. The PAI material used is Torlon® resin from Solvay. The Ensinger TECAPAI product family of high temperature plastics includes polyamide imide moldings in various designs. PAI rods and PAI plates are manufactured using two different processing methods: Extrusion and compression molding. Extrusion offers the advantage that the moldings have physical properties close to those of injection molding. Molded PAI plates can be produced from a minimum order quantity of one piece.


  • Excellent tribological properties and wear resistance
  • Excellent strength and stiffness at elevated temperatures 
  • High tensile strength 
  • High compressive strength
  • Exceptional heat deflection temperature
  • Excellent coefficient of thermal expansion 
  • Very good impact strength
  • Excellent thermal stability
  • Very good machinability
  • High chemical resistance 
  • High wear resistance 
  • Good dielectric properties  
  • Inherently flame retardant
  • Low CTLE
  • Glass transition temperature of up to 400 °C

TORLON versus PEEK? 

Both Torlon® PAI and PEEK are excellent materials for bearing applications.

Torlon® PAI is the preferred solution for seals or for bearings exposed to temperatures above 150 °C. While the stiffness of the material PEEK decreases at temperatures above 150 °C and the thermal expansion rate increases, Torlon® PAI maintains its strength and stiffness at a high level. In addition, the PAI polymer offers superior compressive strength and higher hardness properties, which are critical for many bearing and sealing applications that typically require a high level of wear resistance. PAI exhibits higher tensile and compressive strength in the unreinforced extruded version, which is advantageous in some applications. These PAI properties combined with excellent heat resistance make TECAPAI an excellent bearing and sealing material, even at high temperatures.

PEEK, on the other hand, shows a performance advantage in the area of resistance to chemical induced stresses due to its stout chemical resistance characteristics. PAI absorbs moisture. This leads to a dimensional change. Therefore, PEEK may be the better choice in applications where dimensional stability is the primary concern. 

In summary: Both PAI and PEEK offer excellent property profiles. PAI may have an advantage in tribological performance, strength, thermal stability and toughness, while PEEK has a slight advantage in chemical resistance and shows a more ductile material in the extruded, unfilled version.

Polyamide Imide Applications & PAI Uses

Semiconductor industry: test sockets, electrical connectors and insulators
Aerospace: fasteners, structural components, insulators and other components
Oil and gas: natural gas compressor components, pump components and labyrinth seals
General industry: metal spinning tools, metal replacements, bearing and wear parts and components with increased strength and stiffness requirements