JPS6185710A - Manufacture of heat resistant flat insulated wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a novel method for manufacturing a heat-resistant rectangular insulated wire.

More specifically, the present invention relates to a method for manufacturing heat-resistant rectangular insulated wires used for voice coils of speakers, stator coils of small motors for VTRs, and the like.

[Conventional technology]

There are two methods for manufacturing rectangular insulated wire: one is to roll a round wire to form a rectangular conductor, and the other is to apply and bake an insulating phenol on the outside of the conductor according to a conventional method. There is a method of rolling a rectangular insulated wire to transform it into a rectangular insulated wire, but each method has the following drawbacks. In the former method, when the insulating phenol is applied and baked on the rectangular conductor, its fluidity increases as the temperature of the phenol rises.
The coating on the corners after baking tends to be thin, making it difficult to obtain a coating with uniform thickness. When a rectangular insulated wire with a thin coating at the corners and an exposed conductor surface is used in the coil winding of an electrical device, the reliability of the device is significantly reduced due to poor insulation. On the other hand, in the latter method, although it is possible to obtain a film with a uniform thickness, there is a problem of deterioration of properties due to work hardening of the conductor due to rolling and work deterioration of the insulating film.

Work hardening of a conductor can be made softer by heat treatment, but a film deteriorated by work has poor thermal shock resistance and may crack or peel. As the ratio of thickness to width of the rectangular insulated wire increases, cracks in the coating occur in the anvil, especially when the ratio is 1:5 or more, and the insulation properties are significantly reduced. For this reason, it could not be applied to the winding wire for the above-mentioned purpose.

[Problem that the invention seeks to solve]

The present invention solves the problems of processing deterioration of the insulation film and reduction in thermal shock resistance due to rolling and heat treatment in a method of applying and baking an insulating face on the outside of a conductor with a circular cross section and then rolling it to obtain a rectangular insulated wire. This was done in order to solve the problem.

[Means to solve the problem]

In order to solve the above-mentioned problem, the present inventors studied the resin composition of an insulating face coated with VC on a conductor.

The adhesion between the conductor and the insulating film improves as the heat resistance of the insulating material used increases, such as polyurethane resin, polyester resin, polyester imide resin, etc.
Thermal shock resistance is also improved. On the other hand, when the insulating material is these thermosetting resins, the crosslinking density is high and the insulating film lacks flexibility. Therefore, the plastic deformation of the film cannot follow the plastic deformation of the conductor during rolling, and the amount of deformation is constant. If the temperature is exceeded, cracks may occur in the membrane.

Therefore, the present invention aims to solve the above problem by using a paint made by adding polyesterimide resin to a specific polyetherimide resin and dissolving it in an organic solvent as an insulating face. Explain details.

Polyetherimide resin is a thermoplastic linear polymer represented by the following structural formula.

(In the formula, nii integer, R is a divalent aromatic organic group having 6 to 50 carbon atoms, R' is a 9 divalent organic group selected from alkylene group and cycloalkylene group having 2 to 20 carbon atoms) ) As the structural formula shows, two benzene nuclei are connected by a synothyl molecule, and the rest are imide bonds, which are heat-resistant components, so the ether bonds give flexibility to the film, and the benzene The core and imide bonds contribute to maintaining the heat resistance of the film. An example of this thermoplastic polyetherimide resin is 2,2'-bis(5-(s,+-dicarboxyphenoxy)-phenyl)propanedic anhydride and 4,4
ULTEM is a resin synthesized by solution polycondensation of '-diaminodiphenylmethane and orthodichlorobenzene (the water formed is removed by azeotropy according to a conventional method).
(9'! trade name from GE, USA) corresponds to this.

Polyesterimide at R' is added to the thermoplastic polyetherimide resin as a heat-resistant crosslinking component, and it improves the adhesion between the conductor and the film and has good thermal shock resistance, so it can recover the work hardening of the conductor. It has the effect of preventing the film from cracking and peeling from the conductor during heat treatment for the conductor. In addition, polyesterimide resin has a common imide group with polyetherimide resin, and the compatibility of both resins is good, so that it is dispersed without being unevenly distributed in the polyetherimide resin, and the crosslinking points are uniformly distributed in the film. do.

A specific example of polyesterimide resin is Isomid.
(Product name manufactured by Schenectady Chemicals, USA) [Example] ULTEM1, a thermoplastic polyetherimide resin
20y- and Isomid 809-, which is a thermosetting polyesterimide resin, were weighed and dissolved in a mixed solvent of cresol and Kijirol so that the resin concentration was 20y. Heat-resistant insulation x mt was manufactured on annealed copper wire at a furnace temperature of 450° CJj speed of 50 rr/ali + te so as to have a coating thickness of 7.0 to 7.5 μm. Next, roll this with a roll diameter of 25
111 biaxial rolling mill, heat-resistant rectangular I according to the present invention
I got the PJ edge wire. Pinhole tests based on JIS C5003 (6, 2) were conducted on rectangular insulated wires with various conductor thicknesses and widths.

Regarding the obtained rectangular insulated wire, in order to soften the work-hardened conductor, the furnace temperature was 450°C and the linear speed was 40m/-.
The table below shows the results of a similar trial run for rectangular insulated wires that had been heat-treated. The comparative example shown is the characteristic of a rectangular polyesterimide insulated wire manufactured under the same conditions as in the example using a general-purpose polyesterimide insulating paint for enameled wires as the insulating paint.

Furthermore, the heat resistance of the insulation film of the rectangular insulated wire obtained by the present invention is extremely good, and the thermogravimetric index (TGI), which is used as a measure of heat resistance, is extremely good.
The value of Index 1nDicerbo Method) was extremely high at 180, compared to 120 for a general-purpose polyurethane insulation film, 150 for a polyester insulation film, and 170 for a polyesterimide insulation film.

A: Temperature at the point where the straight line connecting the 20% weight loss point and 50% weight loss point intersects the tangent line at 0% weight loss B: Temperature at the 50% weight loss point K: 2.4833 (The TGI value of polyimide is 24
(Value determined as 0) [Function] The insulating paint used in the present invention is made by adding thermosetting polyesterimide resin to polyetherimide resin made of thermoplastic linear polymer and dissolving it in an organic solvent. Because the polyesterimide resin molecules have long molecular chains, the polyesterimide resin molecules are entangled with each other and react during baking to create an interpenetrating network structure. This film has a molecular structure that deforms relatively easily in response to external stress, and can sufficiently follow the deformation of the conductor, and the stress strain in the film is small. Therefore, the stress and strain caused by rolling and heat treatment can be alleviated within the molecule, so insulation coat II! No cracks will occur. When the insulating coating composition consists only of polyetherimide resin, the film has good removability, but the heat resistance 9 mechanical properties and electrical connectivity are insufficient, and the polyester resin added thereto is It is an indispensable component to compensate for the deficiencies in the above properties. Note that by appropriately selecting the blending ratio of both components and adjusting the density of the interpenetrating network structure, it is possible to control the adhesion, flexibility, and heat resistance of the film.

: Effect of the invention] The heat-resistant rectangular insulated wire obtained by the manufacturing method of the present invention has the following properties:
Since we used a paint made from a combination of a specific polyetherimide resin and polyesterimide resin for the insulation face, countless cracks would occur in the insulation film if the thickness and width ratio of conventional rectangular insulated wires exceeded 1:5. Furthermore, the characteristics of the coating can be maintained even in thinner rectangular insulated wires, which could not be put to practical use due to peeling of the coating. Therefore, by using the rectangular insulated wire according to the method of the present invention as a coil winding of an electrical device, the reliability of the device can be significantly improved.

Claims (1)

[Claims] An insulating paint made by dissolving polyetherimide resin and polyesterimide resin represented by the following structural formula in an organic solvent is applied and baked on a conductor with a circular cross section, and then rolled into a rectangular shape. A method for manufacturing a heat-resistant rectangular insulated wire, characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, n is an integer, R is a divalent aromatic organic group having 6 to 30 carbon atoms, R' is an alkylene group having 2 to 20 carbon atoms, cyclo It is a divalent organic group selected from alkylene groups.)