Applications of the Polyimide Film

PI film is highly versatile and is the first commercial use among various applications of polyimide. It’s by far the best insulating film material, referred to as the “golden film”. PI film is widely used in microelectronics, liquid crystal display, thermal conductive graphite film, rail transportation, aerospace, and the lithium-ion battery etc.

Applications of PI Film

① Microelectronics manufacturing and packaging: The main applications of PI film are FCCL insulating base film and FPC Coverlay. At present, adhesive-free two-layer FCCLs are most used in high-density FPCs. Such FCCLs have higher thermal endurance, dimensional stability, and bonding strength, and are also thinner and have better folding resistance.

Additionally, the technical difficulty of PI film for microelectronics-level packaging is higher than its application in FCCLs. PI film as an electronic packaging material can improve the signal transmission speed.

② Liquid crystal display: the production of AMOLED screen requires PI as substrate. The touch screen of foldable phones based on AMOLED technique needs Colorless PI(CPI) film as base film and cover glass.

③ Thermal conductive graphite film: PI film can be used as thermal conductive films for electronic devices such as tablet PCs and 5G smartphones. Thermal conductive graphite film composed of PI film as an important raw material is the best heat dissipation material for electronic products at this stage.

④ Motor insulating materials: PI film is widely used as electrical insulation film in the manufacture of power transmission and distribution equipment, high-voltage inverter motors, high-speed traction motors and high-voltage transformers. High-performance PI film can also be used for the insulation of various precision motors such as high-power electric locomotives, alternators, and radiation-resistant motors. For instance, polyimide films coated with high performance silicone pressure-sensitive adhesive on one side can be used for class H motor and transformer coil insulation binding, binding and fixing in high temperature resistant coil end, temperature measuring RTD protection, capacitors and wire entanglement and other bonding insulation in high temperature working conditions.

⑤ Kapton polyimide lapped copper Litz wire: adhesive polyimide film can be lapped around bare copper wire to produce electromagnetic wire with excellent electrical performance and moisture resistance. Compared with the traditional enameled wire, it can effectively reduce the thickness of motor inter-turn insulation, and the size of the motor as well as improving the reliability of the motor, so it is widely used in the winding of electrical products in aerospace, rail transportation and other high-end motors. PI lapped copper wire can also be used for voice coils.

⑥ PI separator for lithium-ion battery: the separator is one of the key inner components of lithium-ion batteries. PI separator can part the two electrodes of the battery to prevent a short circuit. The separator is immersed in the electrolyte, with a vast number of micro-pores on its surface, allowing lithium-ions in the electrolyte to pass through.

⑦ Polyimide mica tape: the polyimide film, if combined with mica paper by heat and pressure can be used in wind power motors, high speed rail motors, electromagnetic wires, and other highly demanding fields.