DEVELOPMENT OF ENAMELED WIRE VARIETIES

1) Acetal enameled wire

Acetal enamelled wire is one of the earliest developed varieties in the world. It was put on the market by Germany and the United States in 1930, and developed rapidly in the Soviet Union. There are two kinds of acetal and polyvinyl formal enamelled wire, which were successfully studied in China in the 1960s. Although the temperature resistance grade of the enameled wire is low (105 ° C, 120 ° C), it is widely used in oil immersed transformer due to its excellent high temperature hydrolysis resistance, which has been notarized by all countries in the world. At present, there are still a small number of production in China, especially acetal enameled flat wire used to make transposition conductor, which is used in large transformer.

2) Polyester enameled wire

In the mid-1950s, the polyester enameled wire paint based on dimethyl terephthalate was first developed by West Germany. Because of its good heat resistance and mechanical strength, wide range of painting technology and low price, it has become the main product dominating the enameled wire market since the 1950s. However, due to the poor thermal shock resistance of polyester enameled wire and the easy hydrolysis under high temperature and high humidity conditions, polyester enameled wire as a single coating in the late 1970s was no longer produced in West Germany and the United States, but still produced and used in large quantities in Japan, China and Southeast Asia. Statistics in 1986 show that the output of polyester enameled wire accounts for 96.4% of the total output. After 10 years' efforts, the varieties of enameled wire have been developed, but there is a big gap compared with developed countries.

A lot of work has been done on polyester modification in China, such as THEIC modification and imine modification. However, due to the slow adjustment of enameled wire structure, the production of these two kinds of paints is still small. So far, the problem of voltage drop of modified polyester enameled wire still needs attention.

3) Polyurethane enameled wire

Polyurethane enameled wire paint was developed by Bayer in 1937. Because of its direct welding, high frequency resistance and dyeability, it has been widely used in electronic, electrical and other fields. At present, foreign countries pay great attention to improving the heat resistance of polyurethane enameled wire without affecting its direct welding performance. In Europe, the United States, Japan has developed F-class, H-class polyurethane enameled wire. Due to the rapid development of color TV sets, the polyurethane enamelled wire with large length and salt free pinhole developed by Japan for color TV FBT has attracted the attention of all countries in the world, and is still the leader of Japan at present.

The development of polyurethane enameled wire is slow in China. Although there are some common polyurethane enamels produced by some factories, they are mainly imported due to poor processability, surface quality and other problems. Grade F polyurethane has also been developed in China, but no production capacity has been formed. Large length non pinhole polyurethane paint has also been successfully developed and put on the market. It is mainly used for making FBT coil of black and white TV.

4) Polyesterimide enameled wire

Since 1970s, the amount of polyesterimide enameled wire in the world has increased dramatically. In Europe and America, the enameled wire has completely replaced the polyester enameled wire with single coating. At present, the representative products in the world are the terebe FH series products of Germany and the isomid series products of the United States. At the same time, the direct solderable polyesterimide enameled wire has been developed, which has been widely used as the winding of small motor, simplifying the welding process and reducing the manufacturing cost of motor. In Japan, some direct welded polyesterimide paint is also used as the primer of self adhesive enameled wire for color TV deflection coil, which simplifies the process. Domestic polyesterimide paint has successively introduced manufacturing technology from Germany and Italy, and has also been developed successfully. However, due to the instability of raw materials and other reasons, a large number of domestic polyesterimide paint, which is used as the primer of composite enameled wire with frost resistance agent, still relies on import. Only a small number of single coat polyesterimide enameled wires are made in China, but the voltage instability is still a concern for the manufacturers. The direct solderable polyesterimide paint has been successfully developed by the cable research institute.

5) Polyimide enameled wire

Polyimide is the highest heat-resistant enameled wire paint among organic enameled wires. Its long-term use temperature can reach over 220 ° C. The paint was developed in 1958 in the United States. Polyimide enameled wire has high heat resistance, good solvent resistance and frost resistance. However, because of its high cost, poor storage stability and toxicity, it affects its wide use. At present, the enameled wire is used in some special occasions, such as coal mine motor, space instrument and so on.

6) Polyamide imide paint

Polyamide imide paint is a kind of paint with comprehensive neutral energy, high heat resistance, mechanical property, frost resistance and chemical resistance, so it is called the king of enameled wire paint. At present, the paint is mainly used for its unique performance, widely used as the top coat of composite coated enameled wire, improving the heat resistance of composite wire and reducing the cost. At present, it is mainly used to coat cold resistant enamelled wire in China, which is produced in a small amount in China and mainly imported from the United States, Italy and Germany.

7) Composite coated enameled wire

In order to improve temperature resistance and develop enameled wire for special purpose, composite insulation layer is generally used. Compared with the single coated enameled wire, the composite coated enameled wire has the following advantages: (1) it can meet the special use requirements, such as self-adhesive enameled wire for complex frameless forming, refrigerant resistant enameled wire for refrigerator and air conditioning compressor, etc., which can be met by the composite coating structure; (2) it can improve and improve the use performance through the combination of various insulation layers to meet the use requirements, For example, the polyester / nylon composite coated enameled wire improves the thermal shock performance and winding performance, which is suitable for the thermal impregnation process, and can be used for the instantaneous overheating motor winding caused by overload; (3) it can reduce the cost of some enameled wires, such as polyester imide, polyamide imide composite coated enameled wire instead of single coated enameled wire