Several colleagues were discussing the solution to a enameled copper wire product in the conference room of Tianjin Ruiyuan. Is the enamel copper wire insulation material acetaldehyde resin or polyester? We got the answer after we research.
The nature of the insulating varnish used in enamel copper wire production affects not only the electrical, mechanical, and processing properties of the wire. As two classical and widely used insulating coatings, acetaldehyde resin and polyester varnish differ extremely, resulting in different application field.
In enamel copper wire production, the type of insulating varnish used has a significant impact on the magnet wire’s electrical, mechanical, and processing attributes. As two traditional and popular insulating coatings, acetaldehyde resin and polyester varnishes have emphatically opposite characteristics, which lead to different fields of application.
1. The Different Performance of the Mechanical Properties
Polyvinyl Formal (PVF) varnish is well known for its very high level of scratch resistance and good flexibility. Its coating film has high adhesion and at the same time seems to form a kind of shell around the copper conductor, encapsulating it, and none peeling during winding, tracking or other process is observed. This insulation is exceptional for motor windings which are continually bent or exposed to extreme mechanical stress, such as coils in micro motors and power tools.
In contrast, polyesters (usually modified polyester or polyester imide) have better heat resistance. Ordinary polyester varnishes may have a heat resistance Class of B (130°C) or even F (155°C), while those used in alkyd varnishes usually have a Class A (105°C) or E (120°C) heat resistance. Polyester varnishes also have superior resistance to chemical solvents and good stability to impregnation, since impregnation with polyester varnish is less likely to be affected by swelling or dissolution of solvents. Still, polyester varnishes are a bit less flexible than alkyds and may crack if bent sharply or applied in high speed winding conditions.
2. Comparison Between Electrical Insulation and Moisture-proof Performance
With respect to electrical property, both two samples were subjected to the high breakdown voltage requirement. Acetaldehyde polyethylene enamel has a lower dielectric loss factor, which means that it has more stable insulation within the high frequency range, and therefore can be used in a signal-sensitive apparatus like an audio transformer. On the other hand, polyesters enamel has higher volume resistivity in moist environment and superior water proofing and moisture resistivity and is recommended for use in household appliances subjected to continuous exposure to high humidity such as air-conditioner compressors and submersible pumps.
3. Color Condition of Enamel Wire After Painting
This variation is the most noticeable and is frequently used as a primary discriminating factor. Polyvinyl formal-coated enamelled copper wire is bright deep red or chestnut red and the surface is uniform and glossy. This is due to the chemical composition of the base resin which can be clearly stated from the appearance from other types of enamelled copper wires. On the other hand, the copper magnet wire coated with the polyester resin is usually a light yellow, pale yellow, or a little golden transparent color which is lighter in color accompanied by some products are colorless transparent. In the case of the finished wire diameter is thin, the color of conductor in polyester-enamelled copper wire is often seen in natural copper color with slight yellow tint.
4. Application Scenarios and Overall Selection
In a word, polyvinyl formaldehyde (PVF) enamel copper wire is a flexible and bright red colored enamel copper wire, which is adaptable for small precision motors and electronic coils which are required to have high mechanical bending resistance and having no severe thermal condition. While, the polyester enamel copper wire is a heat resistant, moisture resistant, light color and it is generally used in domestic appliance, industrial motors and transformer windings. Red is for polyvinyl formaldehyde and pale yellow is for polyester, engineers in manufacturing usually can tell a type of materials just by seeing the color of wire in practical production, which make a good convenient for the work.
Post time: Jul-24-2026
