Enameled wire is the main raw material of motor, electrical appliances and household appliances. Especially in recent years, the electric power industry has achieved sustained and rapid growth, and the rapid development of household appliances has brought a broader field for the application of enameled wire, followed by higher requirements for enameled wire. For this reason, it is inevitable to adjust the product structure of enameled wire, and the raw materials (copper and lacquer), enameled process, process equipment and detection means are also in urgent need of development and research [1].
At present, there are more than 1000 manufacturers of enameled wire in China, and the annual production capacity has exceeded 250000 ~ 300000 tons. But generally speaking, the situation of China’s enameled wire is low-level repetition, generally speaking, “high output, low grade, backward equipment”. In this situation, high quality enameled wires for household appliances still need to be imported, let alone to participate in international market competition. Therefore, we should redouble our efforts to change the status quo, so that China’s enameled wire technology can keep up with the market demand, and compete in the international market.

Development of different varieties
1) Acetal enameled wire
Acetal enamelled wire is one of the earliest varieties in the world. It was put on the market by Germany and the United States in 1930. The Soviet Union also developed rapidly. There are two kinds of polyvinyl formal and polyvinyl acetal. China also successfully studied them 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. This characteristic 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 is used to make transposed conductor for large transformer [1].
2) Polyester enameled wire
In the mid-1950s, West Germany first developed the polyester enameled wire paint based on dimethyl terephthalate. Because of its good heat resistance and mechanical strength, wide range of paint making process 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 and easy hydrolysis under high temperature and high humidity conditions, polyester enameled wire as a single coating was no longer produced in West Germany and the United States in the late 1970s, 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 in China accounts for 96.4% of the total output. After 10 years of 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, including THEIC modification and imine modification. However, due to the slow structural adjustment of enameled wire, the production of these two kinds of paints is still small. So far, the voltage drop of modified polyester enameled wire still needs to be paid attention to.
3) Polyurethane enameled wire
Polyurethane enamelled wire paint was developed by Bayer in 1937. It is widely used in the fields of electronics and electrical appliances because of its direct solderability, high frequency resistance and dyeability. At present, foreign countries pay great attention to improving the heat resistance grade of polyurethane enameled wire without affecting its direct welding performance. In Europe, the United States, Japan has developed a F-class, H-class polyurethane enameled wire. Due to the rapid development of color TV sets, the polyurethane enameled wire with large length salt free pinhole for color TV FBT developed by Japan has attracted the attention of all countries in the world, and it is still ahead of Japan .
The development of domestic polyurethane enameled wire is slow. Although common polyurethane paint is produced by some factories, due to poor processability, surface quality and other problems, the paint is mainly imported. Grade F polyurethane has been developed in China, but no production capacity has been formed. Large length pinhole free polyurethane paint has also been successfully developed and put on the market, mainly used for making FBT coil of black and white TV.
4) Polyesterimide enameled wire
Due to the improvement of heat resistance through modification of polyesterimide, the amount of polyesterimide enameled wire in the world has increased sharply since 1970s. In Europe and America, the enameled wire has completely replaced the single coating polyester enameled wire. At present, the representative products in the world are terebe FH series products from Germany and isomid series products from the United States. At the same time, we have developed direct solderable polyesterimide enameled wire, which has been widely used as the winding of small motor, simplifying the welding process and reducing the manufacturing cost of motor. Some Japanese also use direct solderable polyesterimide paint as the primer of self-adhesive enameled wire for color TV deflection coil, which simplifies the process. Domestic polyesterimide paint has 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 used as refrigerant resistant composite enameled wire primer still relies on imports. Only a small number of single coating polyesterimide enameled wires are applied with domestic paint, but the instability of voltage is still a concern of manufacturers. Direct solderable polyesterimide paint has been successfully developed by Cable Research Institute.
5) Polyimide enameled wire
Polyimide is the most heat-resistant enameled wire paint among the organic enameled wires at present, and its long-term service temperature can reach above 220 ° C. The paint was developed by the United States in 1958. Polyimide enameled wire has high heat resistance, good solvent resistance and refrigerant resistance. However, due to its high cost, poor storage stability and toxicity, its wide use is affected. 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 enameled wire paint with comprehensive neutral performance, high heat resistance, mechanical properties, refrigerant resistance and chemical resistance, so it has the reputation of king of enameled wire paint. At present, the paint is mainly used for its unique properties, and is widely used as the topcoat of composite coating enameled wire to improve the heat resistance of composite wire and reduce the cost. At present, it is mainly used to coat the frost resistant enameled wire in China, and a small amount of this paint is produced in China, mainly imported from the United States, Italy and Germany .
7) Composite coating enameled wire
Composite insulation layer is generally used to improve the temperature resistance grade and develop special purpose enameled wire. Compared with single coating enameled wire, the composite coating enameled wire has the following advantages: (1) it can meet the special application requirements, such as self-adhesive enameled wire for complex frameless forming, refrigerant resistant enameled wire for refrigerator and air conditioner compressor, etc., which can be met through the composite coating structure; (2) it can improve and improve the service performance through the combination of various insulation layers to meet the application requirements, For example, polyester / nylon composite coating enameled wire improves the thermal shock performance and winding performance, which is suitable for hot dipping process, and can be used for motor windings with instantaneous overheating due to overload; (3) it can reduce the cost of some enameled wires, such as polyester imide and polyamide imide composite coating enameled wire replacing single coating polyamide imide enameled wire, which can greatly reduce the cost.

classification
1.1 according to insulation material
1.1.1 acetal enameled wire
1.1.2 polyester paint wrapping wire
1.1.3 polyurethane coating wire
1.1.4 modified polyester paint wrapping wire
1.1.5 polyester imimide enameled wire
1.1.6 polyester / polyamide imide enameled wire
1.1.7 polyimide enameled wire
1.2 according to the purpose of the enameled wire
1.2.1 general purpose enameled wire (common line): it is mainly used for winding wires in general motors, electrical appliances, instruments, transformers and other working occasions, such as polyester paint wrapping wire and modified polyester paint wrapping line.
1.2.2 heat resistant coating line: winding wires mainly used in motor, electrical appliances, instruments, transformers and other working occasions, such as polyester imimide coating wire, polyimide coating wire, polyester paint coating line, polyester imimide / polyamide imide composite coating line.
1.2.3 special purpose enameled wire: refers to winding wire with certain quality characteristics and used in specific occasions, such as polyurethane paint wrapping wire (direct welding property), self adhesive paint wrapping wire.
1.3 according to the conductor material, it is divided into copper wire, aluminum wire and alloy wire.
1.4 according to the material shape, it is divided into round line, flat line and hollow line.
1.5 according to insulation thickness
1.5.1 round line: thin Film-1, thick film-2, thickened film-3 (national standard).
1.5.2 flat line: ordinary paint Film-1, thickened paint film-2.
Alcohol line
Wire (e.g. lock) that is self-adhesive under the action of alcohol
Hot air line
Wire (e.g. PEI) which is self-adhesive under the action of heat
Double wire
Wire that is self-adhesive under the action of alcohol or heat
Representation method
1. symbol + code
1.1 series code: composition of enameled winding: q-paper wrapping winding wire: Z
1.2 conductor material: Copper Conductor: t (omitted) aluminum conductor: l
1.3 insulation materials:
Y. A polyamide (pure nylon) e acetal, low temperature polyurethane B polyurethane f polyurethane, polyester h polyurethane, polyester imides, modified polyester n polyamide imide composite polyester or polyesterimide polyamide imide r polyamide imide polyimide C-aryl polyimide
Oil based paint: Y (omitted) polyester paint: Z modified polyester paint: Z (g) acetal paint: Q polyurethane paint: a polyamide paint: X polyimide paint: y epoxy paint: H polyester imimide paint: ZY polyamide imide: XY
1.4 conductor characteristics: flat line: b-circle line: Y (omitted) hollow line: K
1.5 film thickness: round line: thin Film-1 thick film-2 thickened film-3 flat line: ordinary Film-1 thickened film-2
1.6 thermal grade is expressed by /xxx
2. model
2.1 the product model of enameled line is named by the combination of Chinese pinyin letter and Arabic numerals: its composition includes the following parts. The above parts are combined in sequence, which is the product model of the paint package line.
3. model + specification + standard number
3.1 examples of product representation
A. Polyester enamelled iron round wire, thick paint film, heat grade 130, nominal diameter 1.000mm, according to gb6i09.7-90 standard, expressed as: qz-2 / 130 1.000 gb6109.7-90
B. Polyester imides are coated with iron flat wire, ordinary paint film, with heat grade of 180, side a of 2.000mm, side B of 6.300mm, and the implementation of gb/t7095.4-1995, which is expressed as: qzyb-1/180 2.000 x6.300 gb/t7995.4-1995
3.2 oxygen free round copper stalk
Enameled wire
Enameled wire
3.2.1 series code: round copper pole for electrical engineering
3.2.3 according to the state characteristics: soft state R, hard state y
3.2.4 according to performance characteristics: level 1-1, level 2-2
3.2.5 product model, specification and standard number
For example: diameter is 6.7mm, and class 1 hard oxygen free round copper rod is expressed as twy-16.7 gb3952.2-89
3.3 bare copper wire
3.3.1 bare copper wire: t
3.3.2 according to the state characteristics: soft state R, hard state y
3.3.3 according to the shape of material: flat line B, circular line y (omitted)
3.3.4 example: hard round iron bare wire with diameter of 3.00mm ty3.00 gb2953-89