How much do you know about polyimide (PI) films?

Polyimide (PI) has a long history and is known as one of the "most promising engineering plastics of the 21st century", and in 1908 Bogert first synthesized PI, a class of polymer compounds with imide rings on the main chain. PI has excellent thermal resistance, mechanical properties, electrical insulation properties, radiation resistance and good chemical stability, which makes it widely used in electric power, electrical appliances, aerospace and other neighborhoods. The application of PI film in insulating materials and structural materials is expanding, and it is also emerging in functional materials, and has great potential.

Types of polyimide films

Polyimide film (PIF), also known as PI film, is made by salivating from PAA solution and then imitating. Film is the earliest commercial product form of polyimide, and it is also the main product form of China's polyimide industry, accounting for more than 70%, and it is widely used in the fields of copper clad laminates, flexible displays and insulating materials.

From a technical point of view, there are many types of PI films, and there are four common ones: black PI film, brown and yellow PI film, transparent PI film and corona-resistant PI film, of which the latter three are mainly prepared by chemical imine method, which is also the main application variety in the high-end market.

According to different application categories, PI films can be divided into electrical PI films, electronic PI films, thermal control PI films, aerospace PI films, flexible display CPI films, etc.

Electrical PI film is mainly used in the field of electrical insulation, including high-grade insulation systems such as motors and transformers, and its key characteristics include temperature resistance grades, dielectric strength, products with corona resistance, and can also be used in insulation systems in high-speed rail transit and wind power generation.

Electronic PI film is mainly used in the field of electronic substrates, as an insulating base film and copper foil lamination to form the substrate part of FCCL, can also be covered on the surface of the FPC to play a protective role, meet the requirements of high-frequency and high-speed transmission, and can also be used in the field of 5G communication.

Thermal control PI film is mainly used in the field of electrical thermal control system, such as high thermal conductivity graphite film precursor PI film is made into high thermal conductivity graphite film after carbonization, graphitization and other processing processes for heat dissipation and heat conduction, and the specially designed PI film structure has the characteristics of easy graphitization and suitable for whole roll firing.

PI films for aerospace are mainly used as thermal control or protective materials for space vehicles, and need to have excellent high and low temperature resistance, radiation resistance, low vacuum mass loss and low condensation volatiles.

CPI films for flexible display are used in the fields of device optical covers, mainly used as OLED screen covers, touch sensor panels, etc., and need to have high light transmittance, bending resistance and other characteristics.

Polyimide film is mainly used

1) Polyimide film in the electronic field is widely used in the electronic field. Due to its excellent insulation, high temperature resistance and mechanical strength, it is often used as an insulating layer for electronic components, a substrate for circuit boards, and a substrate material for flexible electronic products. It can be found in electronic products such as smartphones and tablets.

2) Aerospace fieldIn the aerospace field, polyimide film also plays an indispensable role. Due to its high strength and high temperature resistance, it is widely used in the thermal protection system of aircraft, rockets and other aircraft to ensure the safety of aircraft.

3) With the rise of new energy vehicles in the automobile industry, the application of polyimide film in the automobile industry has gradually increased. It can be used as a battery separator to improve the energy density and safety of the battery. At the same time, polyimide film can also play an important role in the manufacture of lightweight vehicles, helping to achieve energy saving and emission reduction of automobiles.

4) The biocompatibility and good mechanical properties of polyimide film in the biomedical field make it an ideal material in the biomedical field. It can be used to make artificial organs, biosensors and other medical devices to escort human health.

5) In addition to the above fields in daily life, polyimide film can also be seen everywhere in our daily life. For example, it can be used to make high-temperature insulated wires, food packaging materials, sports equipment, etc., to provide convenience in our lives.