Polyetherimide (PEI for short) is a class of polymers that contain both ether linkages and imide groups in repeating structural units. [1] is an engineering plastic made of amorphous polyetherimide. Polyetherimide has the best high temperature resistance and dimensional stability, as well as chemical resistance, flame retardancy, electrical properties, high strength, high rigidity, etc. PEI resin can be widely used in high temperature resistant terminals, IC bases, lighting equipment, FPCB (flexible circuit board), liquid delivery equipment, aircraft internal parts, medical equipment and household appliances, etc.