JPS6356653B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a new manufacturing method for obtaining insulated wire for winding used in electrical equipment by extrusion without using a solvent. The conventional method for manufacturing insulated wires uses formal resin, polyester resin, polyesterimide resin, polyamideimide resin, polyimide resin, polyamide resin, etc. as a base resin, and then adds phenol resin, melamine resin, isocyanate resin, aniline resin, etc. The insulating varnish is prepared by blending a hardening agent such as the above and dissolving it in a volatile dispersant such as an organic solvent, and then coating and baking the insulating varnish 5 to 10 times on the conductor. In this method, any resin that dissolves in a solvent can be used as the resin for forming the coating film, and even when several types of resin are mixed, they can be uniformly coated using a common solvent. This method has been practiced for a long time because of its ability to be dispersed and the ability to form relatively thin films on conductors, such as magnet wires. However, in this method, the solvent of the varnish is removed from the coating film by evaporation during the manufacturing process, resulting in extremely large losses of the solvent, and recently pollution problems due to air pollution have also been raised. Furthermore, since the content of resin, which is an active ingredient in coating film formation, contained in the varnish is small, the coating thickness formed by one coating is extremely thin, and it takes many coats to obtain the desired coating thickness. It is necessary to repeat the painting process, and when baking the paint film during this process, the varnish painted on the inside is not completely solidified and dried, and the varnish is baked on the surface with the varnish remaining. As a result, the solvent or dispersant remaining in the internal coating film evaporates, resulting in the formation of pinholes and bubbles in the coating film on the surface side. On the other hand, the method of extruding a high melting point synthetic resin onto a conductor using an extruder to form a magnet wire can almost eliminate the problems inherent in the conventional enamel baking method as described above. Compared to the heat-resistant polyester-imide wire and polyamide-imide wire, it has disadvantages such as a slightly lower heat softening temperature due to the lack of chemical cross-linking points, because it is used as a coating material. Ta. However, recently, polyether ether ketone (manufactured by ICI, UK, hereinafter referred to as PEEK) has been developed as a heat-resistant thermoplastic resin with good molecular structure symmetry and abundant benzene nuclei in the monomer unit, and it is used as a conductor. When we measured the heat softening temperature of the enameled wire coating extruded as an enameled wire with a coating thickness of 45μ, we confirmed that it had a relatively high heat softening temperature between polyesterimide wire, polyamideimide wire, and polyimide wire. It was done. However, PEEK currently has the drawbacks of being too expensive and having poor extrusion processability for practical use as an industrial product; Polyether sulfon (hereinafter referred to as PES) is used as a resin, and it is cheaper than PEEK and has good extrusion processability, but when used as an enameled wire, it has the disadvantage of a much lower thermal softening temperature than PEEK. There is. Considering the above points, this invention created a new insulated wire by combining the advantages and disadvantages of PEEK and PES. This is a method for manufacturing an insulated wire, in which a conductor is extruded and coated with a polyetheretherketone-added mixture shown in the following. In carrying out the present invention, a mixture of the polyether sulfone and polyether ether ketone in a weight ratio of 60:40 to 40:60 is preferred in terms of extrusion processability and heat resistance. That is, if the amount of polyether sulfon is less than this range, the extrusion processability will be poor, and if it is too much, the heat resistance will be low. Next, examples will be described. Example 1 A mixture of PES and PEEK mixed at a weight ratio of 50:50 was coated on a conductor with a diameter of 1.0 mm using a 45 mm extrusion coating machine, at a temperature of 430 °C and a linear speed of 200 °C at the head of the extruder.
The insulated wire of this invention was manufactured by extrusion coating to a coating thickness of 41 μm at m/min. Example 2 An insulated wire of the present invention was obtained under the same conditions as in Example 1 using a mixture of PES and PEEK in a weight ratio of 60:40. Example 3 An insulated wire of the present invention was obtained under the same conditions as in Example 1 using a mixture of PES and PEEK in a weight ratio of 40:60. Comparative Example 1 An insulated wire was manufactured under the same conditions as in Example 1 using only PES. Comparative Example 2 An insulated wire was manufactured under the same conditions as in Example 1 using only PEEK. A comparison of the insulated wires of the example and comparative example is shown in the following table.

[Table] (Note) ◎ Excellent ○ Good △ Fair × Difficult As can be seen from the table above, each insulated wire of the embodiments of this invention has good wire forming workability and can exhibit performance almost similar to PEEK. be.

Claims (1)

[Claims] 1 Polyether sulfone has the structural formula 1. A method for producing an insulated wire, which comprises extruding and coating a conductor with a polyetheretherketone-added mixture represented by the formula.