Application of Continuous Biaxially Stretched Polyimide Film in Motor Insulation

2022-02-07 10:18:28

Continuous biaxially oriented polyimide film is a new type of high temperature resistant organic polymer film, which is made of pyromellitic dianhydride (PMDA) and diaminodiphenyl ether (ODA) in a very strong solvent dimethyl ethyl acetate. Polyimide (DMAC) is polycondensed and drooled to form a film, and then imidized. Polyimide film is currently the world's best-performing thin-film insulating material, with excellent mechanical properties, electrical properties, chemical stability and High radiation resistance, high temperature resistance and low temperature resistance (-269 ° C to +400 ° C). In 1959, DuPont first synthesized aromatic polyimide, and in 1962, it was trial-produced polyimide film (PI). Film), started production in 1965, the trade name is KAPTON. In the late 1960s, polyimide film can be produced in small batches in my country, and now it has been widely used in aviation, navigation, spacecraft, rocket missiles, atomic energy, electrical and electronic industries and other fields .

1. Continuous biaxially oriented polyimide films are used in ribbon cables and flexible printed circuits.

Due to its softness, good dimensional stability and excellent dielectric properties, the film is suitable for use as a substrate or cover for ribbon cables or flexible printed circuits. Corrosion, welding and other high temperature and chemical treatment, the ribbon cable or flexible printed circuit made of it is small in size, light in weight, high in reliability, high temperature resistance, radiation resistance, suitable for micro circuits such as computers.

2. Continuous biaxially oriented polyimide film is used in wrapping magnet wire.

The film is used as the base material, and one or both sides are coated with polyperfluoroethylene propylene emulsion to make an adhesive tape. This adhesive tape can be wrapped around a bare copper wire, and then enters a high temperature furnace (about 350 ℃), and the film shrinks due to shrinkage. It is closely attached to the wire, so that the layers of the wrapped adhesive tape are melted into a whole. When the wire is cooled out of the high temperature furnace, a pair of pressing rollers are added on both sides of the wire to improve the bonding strength between the layers of the adhesive tape. Features: good heat resistance , The thickness of the insulating layer is thin and uniform, and the sealing performance is good, which improves the moisture-proof performance, electrical performance and anti-cutting performance of the wire. Due to the good flexibility of the film, the insulating layer of the wire is intact when it is bent, and there is no cracking phenomenon. It is suitable for H class, Class F motor windings. The thickness of the inter-turn insulation is about 1/3 thinner than that of the double-wire enameled wire, with good thermal conductivity, reducing the size of the motor and improving the reliability of the motor. Widely used in spacecraft, high-voltage motors, locomotive traction motors, deep well submersible pumps Motors and metallurgical motors, etc.

3. Continuous biaxially oriented polyimide film is used in electrical insulation.

In addition to excellent thermal, electrical and mechanical properties, polyimide film can withstand compressive creep at high temperature, and it is suitable for single-layer or compounded with aramid fiber paper for H-class small and medium-sized motor slot insulation. It can also be used for ground insulation and other auxiliary insulation of mining motors and locomotive traction motors. Using polyimide film instead of glass varnished cloth as slot insulation can increase the full rate of wire slots by 8%. Under the same frame conditions, the motor power can be improved. About 20%. In addition, polyimide film can also be used as insulation for high-power electric locomotives, alternators, anti-radiation motors and various precision motors.