1) Acetal enameled wire

Acetal enameled wire is one of the earliest types in the world. It was invested by Germany and the United States in 1930. The Soviet Union also developed quickly. There are two types of polyvinyl formal and polyvinyl acetal. The study of the age was successful. Although the enameled wire has a low temperature resistance level (105°C, 120°C), it is widely used in oil-immersed transformers because of its high-temperature hydrolysis resistance. This feature has been notarized by various countries in the world, and there are still a few in my country. Produced, especially the acetal enameled flat wire used to make transposition wires, used in large transformers.

  2) Polyester enameled wire

In the mid-1950s, West Germany first developed a polyester enameled wire paint based on dimethyl terephthalate because of its good heat resistance and mechanical strength, wide paint processing range, and low price. It became the primary product dominating the enameled wire market. However, due to the poor thermal shock resistance of polyester enameled wire and easy hydrolysis under high temperature and high humidity conditions, the polyester enameled wire as a single coating in the late 1970s is no longer produced in West Germany and the United States, but in Japan, my country and Southeast Asia The region is still produced and used in large numbers. Statistics in 1986 indicated that the output value of polyester enameled wire in our country accounted for 96% of the total output value. After 10 years of hard work, the types of enameled wire have been developed, but it is far away from developed countries.

  Domestic polyester modification has also done a lot of work, both THEIC modification and imine modification have been researched and developed, but because of the slow adjustment of the enameled wire structure, the output value of these two paints is still not large. Up to now, the voltage drop of modified polyester enameled wire still needs everyone's attention.

Enameled wire

  3) Polyurethane enameled wire

   Polyurethane enameled wire paint was developed by Bayer in Germany in 1937. Because of its direct solderability, high frequency resistance and dyeability, it is widely used in electronics and electrical appliances. Now foreign countries attach great importance to improving the heat resistance of polyurethane enameled wire without affecting its direct welding function. In Europe, the United States, and Japan, it has successively developed F grade and H grade polyurethane enameled wires. Because of the rapid development of color TVs, the large-length, salt-free pinhole polyurethane enameled wire developed by Japan for color TV FBT has attracted the attention of countries all over the world, and it is still Japan.

   The development of domestic polyurethane enameled wire is slow. Although the general polyurethane paint is produced by some factories, because of poor workmanship and surface quality, the paint is still imported. F grade polyurethane has also been developed in China, but the production capacity has not been formed. Large-length, pinhole-free polyurethane paint has also been successfully developed and put into the market, mainly for the production of black and white TV FBT coils.

  4) Polyesterimide enameled wire

Because the heat resistance has been improved by modifying polyester with imine, since the 1970s, the amount of polyester imine enameled wire in the world has risen sharply. In Europe and America, this enameled wire has replaced single-coated polyester enameled wire. The representative ones in the world are the Terebe FH series products from Germany and the Isomid series products from the United States. At the same time, it has also developed direct-weldable polyester imide enameled wire, which has been widely used as the winding of small motors, which simplifies the welding process and reduces the production cost of the motor. Some Japanese also use direct-welding polyester imine paint as the primer of self-adhesive enameled wire used in the deflection coil of color TV, which simplifies the process. Domestic polyester imine paints have successively introduced production skills from Germany and Italy, and have also succeeded in their own research and development. However, due to the instability of raw materials and other reasons, a large number of domestic polyester imine paints that are used as refrigerant-resistant composite enameled wire primers still rely on Imported. Only a few single-coated polyester imine enameled wires use domestic paint, but voltage instability is still a concern for manufacturers. Direct solderable polyester imine paint has been successfully developed by the Cable Research Institute.

  5) Polyimide enameled wire

  Polyimide is a heat-resistant enameled wire paint among organic enameled wires, and its long-term use temperature can reach 220°C or more. The paint was successfully developed by the United States in 1958. Polyimide enameled wire has high heat resistance, outstanding solvent and refrigerant resistance. But because of its high cost, poor storage stability and toxicity, it has affected its wide use. Now the enameled wire is used in some special occasions, such as wires used in coal mine motors, space instruments and meters.

  6) Polyamide-imide paint

   Polyamide-imide paint is more functional among enameled wire paints. It has high heat resistance, mechanical function, refrigerant resistance and chemical resistance, so it has the reputation of enameled wire paint. The paint is now mainly used for its unique functions, and is widely used as the top coat of composite coated enameled wires to improve the heat resistance of composite wires and reduce costs. At present, it is mainly used to coat refrigerant-resistant enameled wire in China. This paint is produced in a few domestically, mainly imported from the United States, Italy and Germany.

  7) Composite coating enameled wire

   To improve the temperature resistance level and develop enameled wires for special applications, composite insulation layers are generally used. Compared with single-coated enameled wire, composite coating enameled wire has the following advantages: (1) It meets special application requirements, such as self-adhesive enameled wire for complex frameless forming, refrigerant resistant enameled wire for refrigerators and air-conditioning compressors, etc., can pass through composite coating structure To meet the requirements; (2) Through the compounding of various insulating layers, it can improve its characteristics and improve its application functions to meet application requirements. For example, polyester/nylon composite coated enameled wire has improved thermal shock and winding functions, and is suitable for heat The dipping process can be used for motor windings that are overheated due to overload; (3) It can reduce the cost of some enameled wires, such as polyester imide, polyamide-imide composite coating aluminum magnet wire instead of single coating The polyamide-imide enameled wire can greatly reduce the cost.