PI conductive film is a material that combines the high temperature stability and conductive properties of polyimide (PI) film. It achieves conductive properties by coating a layer of indium tin oxide (ITO) film on the surface of polyimide (PI) film. This structure makes it widely used in applications that require high transparency, high temperature stability and conductive properties. The production process is basically a two-step process. First, polyamic acid is synthesized, and then polyimide film is made through a film-forming imidization process. This material is suitable for the use of flexible solar cells or related devices in laboratories.
This material is the best performing thin-film insulating material in the world. It is made of pyromellitic anhydride (PMDA) and diaminodiphenyl ether (ODA) in a strong polar solvent through polycondensation and cast film formation and then imidization.
Polyimides are generally divided into two categories
Thermoplastic polyimides, such as imide films, coatings, fibers and modern microelectronics polyimides.
Thermosetting polyimides mainly include bismaleimide (BMI) type and monomer reactant polymerization (PMR) type polyimides and their respective modified products. BMI is easy to process but brittle.
Its main characteristics
It is yellow and transparent, with a relative density of 1.39 to 1.45. Polyimide film has excellent high and low temperature resistance, electrical insulation, adhesion, radiation resistance, and medium resistance. It can be used for a long time in the temperature range of -269℃ to 280℃, and can reach a high temperature of 400℃ for a short time.
Polyimide is the most heat-resistant variety among industrialized polymer materials. It is widely used in high-tech fields as films, coatings, plastics, composite materials, adhesives, foam plastics, fibers, separation membranes, liquid crystal orientation agents, photoresists, etc. In the late 1960s, my country was able to produce polyimide films in small batches, and it has been widely used in various fields such as aviation, navigation, spacecraft, rockets and missiles, atomic energy, and electronic and electrical industries.
The main advantages of this material
(1) Excellent heat resistance. The decomposition temperature of polyimide is generally over 500℃, sometimes even higher. It is one of the most thermally stable varieties of known organic polymers. This is mainly because the molecular chain contains a large number of aromatic rings.
(2) Excellent mechanical properties. The tensile strength of the unreinforced matrix material is above 100 MPa. The tensile strength of the Kapton film prepared with anhydride is 170 MPa, while that of biphenyl polyimide (Upilex S) can reach 400 MPa. The elastic modulus of polyimide fiber can reach 500 MPa, second only to carbon fiber.
(3) Good chemical stability and moisture and heat resistance. Polyimide materials are generally insoluble in organic solvents and are resistant to corrosion and hydrolysis. Varieties with different structures can be obtained by changing the molecular design. Some varieties can withstand boiling in water at 120°C for 500 hours at 2 atmospheres.
(4) Good radiation resistance. After irradiation with a dose of 5×109 rad, the strength is still maintained at 86%; after some polyimide fibers are irradiated with 1×1010 rad fast electrons, their strength retention rate is 90%.
(5) Good dielectric properties. The dielectric constant is less than 3.5. If fluorine atoms are introduced into the molecular chain, the dielectric constant can be reduced to about 2.5, the dielectric loss is 10, the dielectric strength is 100 to 300 kV/mm, and the volume resistivity is 1015-17 Ω·cm. Therefore, the synthesis of fluorinated polyimide materials is a popular research field.
In summary, PI conductive film is a thin film insulating material with excellent performance in the world. It is made of pyromellitic acid and diaminodiphenyl ether in a strong polar solvent through polycondensation and cast film formation and then imidization. It is particularly suitable for use as a flexible printed circuit board substrate and various high-temperature resistant motor and electrical insulation materials.