JPH0828131B2 - Resin composition for electric insulation and insulated electric wire - Google Patents

Description

The present invention relates to a resin composition for electrical insulation and an insulated wire.

[Conventional technology]

Conventionally, insulated electric wires (hereinafter, abbreviated as enamel wires) obtained by applying and baking a synthetic resin composition such as polyvinyl formal, polyurethane, polyester, polyester imide, and polyamide imide on a conductor are motors depending on the characteristics of each paint. It is used in various applications such as transformers and transformers.

In recent years, electric manufacturers using enameled wires have begun to introduce automatic high-speed winding machines in order to rationalize the manufacturing process of equipment.
There is a growing problem that the insulating layer is apt to be mechanically damaged by friction, impact, etc., causing a layer short circuit, a grounding failure, etc., and increasing the failure rate. Therefore, in order to reduce such mechanical damage, an enameled wire having excellent lubricity has been demanded.

Since the enameled wire alone has poor lubricity, a method of applying liquid paraffin, solid paraffin, insulating oil, wax, etc. onto the enameled wire has been used as a means to solve this problem, as well as excellent mechanical strength and abrasion resistance. The method of overcoating nylon was applied. However, among these methods, the method of applying paraffin or the like is such that when the enamel wire is wound on a motor or a transformer and then varnished with an impregnating varnish or a casting resin, paraffin, oil, and wax are not treated with the impregnating varnish or casting. Due to the poor affinity with the resin, there are problems such as poor adhesion and easy occurrence of voids. Also, with the method of overcoating nylon, etc., it is not possible to bake under the same conditions (furnace temperature, baking speed, etc.) as the baking wire of the undercoat enamel wire, which reduces productivity and also cut-through temperature etc. In many cases, the enamelled wire characteristics of the product are deteriorated and the price is high, so that the range of use was limited. Therefore, a method of overcoating a synthetic resin paint for enameled wire in which wax or low-molecular-weight polyethylene is dispersed under the same conditions as the undercoating paint has been studied.

However, waxes and low-molecular-weight polyethylene have poor compatibility with synthetic resins for enameled wires and solvents, so it is difficult to disperse them in synthetic resin paints for enameled wires, and methods such as vigorous stirring are used. However, even if it was forced to disperse with, there was a drawback that waxes and low-molecular-weight polyethylene were separated in a short time.

[Problems to be Solved by the Invention]

The present invention solves the above-mentioned drawbacks of the prior art, and provides a resin composition for electrical insulation, which has excellent slipperiness, good dispersibility of a lubricant, excellent varnish stability, and can form a self-lubricating film. is there.

[Means for solving the problem]

The present invention relates to (A) 0.1 to 10 parts by weight of a partially saponified ester wax and (B) a low molecular weight polyethylene having a number average molecular weight of 5,000 or less with respect to 100 parts by weight of a resin content of an enamel wire synthetic resin coating material.
The present invention relates to an electrical insulating resin composition containing 0.1 to 10 parts by weight, and an enameled wire obtained by applying and baking the resin composition on a conductor directly or through another insulating material.

As the partially saponified ester wax used in the present invention, [Wherein R represents a hydrocarbon group having 28 to 32 carbon atoms] and its derivatives, and the molecular weight is about
800 is preferable. Examples include Hoechst wax OP, Hoechst wax X55, Hoechst wax O, Hoechst wax OM, and Hoechst wax FL manufactured by Hoechst Japan Ltd. Waxes other than the partially saponified ester wax have poor compatibility with the low molecular weight polyethylene as the component (B) and have poor dispersibility.

The partially saponified ester wax is added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the resin content of the paint. If the addition amount is less than 0.1 part by weight, the effect of slipperiness is poor, and if it exceeds 10 parts by weight, the appearance of the enamel wire is poor.

Next, the low molecular weight polyethylene blended as the component (B) is not particularly limited as long as it has a number average molecular weight of 5000 or less. When the number average molecular weight exceeds 5,000, dispersibility is poor. The low molecular weight polyethylene is added in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin content of the coating material. If the amount added is less than 0.1 parts by weight, the effect of slipperiness will not be obtained, and if it exceeds 10 parts by weight, the appearance of the enameled wire will be extremely deteriorated.

Even if only the partially saponified ester wax is attempted to be dispersed in the synthetic resin coating for the enamel wire, the dispersion state is poor and a coarse non-uniform dispersion system is formed, and the layers are separated in a short time.

On the other hand, when only low molecular weight polyethylene is similarly dispersed in the synthetic resin coating for enamel wire, not only the dispersion stability is poor, but also the resulting enamel wire surface has large irregularities, resulting in a marked deterioration in appearance. .

However, surprisingly, when the above partially saponified ester wax and low molecular weight polyethylene are used in combination, the dispersibility is remarkably improved, and a stable dispersed state is maintained even with the passage of time.
It has been found that the enamel wire produced using this has a good appearance and is also excellent in self-lubricating property.

As a method of dispersing the partially saponified ester wax and low molecular weight polyethylene in the synthetic resin coating for enamel wire, even if added directly, it does not disperse well.First, disperse the partially saponified ester wax and low molecular weight polyethylene in the solvent. Then, a method of adding this to the synthetic resin paint for enameled wire and dispersing it is preferable. Examples of the solvent include aromatic hydrocarbons such as cresol and xylene. The content of partially saponified ester wax and low molecular weight polyethylene in the solvent dispersion is preferably 1 to 20% by weight, but is not particularly limited.

Synthetic resin paints for enameled wires include paints containing resins such as polyvinyl formal, polyurethane, polyester, polyester imide, and polyamide imide.

Although the resin composition of the present invention can be directly baked on a conductor to produce an enamel wire, it is preferable to apply it through another insulating material, to bake it for overcoating, and to use it as a double-coated wire.

By using the resin composition according to the present invention in which a partially saponified ester wax and low molecular weight polyethylene are mixed in a paint using the same base resin as the base coating, it is aimed at the same conditions as the baking conditions of the synthetic resin paint for enamel wire. A self-lubricating double-coated wire can be obtained.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 100 g of Hoechst wax OP was dissolved by heating in 1000 g of xylene, and after cooling, 100 g of low molecular weight polyethylene (Mitsui Petrochemical Industry Co., Ltd. trade name Mitsui High Wax 420M, number average molecular weight 4000) was added and stirred. Dispersion was performed to obtain a dispersion liquid (hereinafter, referred to as dispersion liquid X). This dispersion is a paste in which wax and polyethylene are uniformly dispersed. 5 g of Dispersion X was added to 400 g of polyester varnish WH-4060 (manufactured by Hitachi Chemical Co., Ltd., resin content 40% by weight) and dispersed by stirring to obtain a resin composition.

Example 2 50 g of Dispersion X was added to 400 g of polyester varnish WH-4060 and dispersed by stirring to obtain a resin composition.

Example 3 100 g of Dispersion X was added to 400 g of polyester varnish WH-4060, and dispersed by stirring to obtain a resin composition.

Comparative Example 1 Polyester varnish WH-4060 was directly used as a comparative example.

Comparative Example 2 10 g of Hoechst wax OP was heated and dissolved in 100 g of xylene to obtain a dispersion liquid (hereinafter, referred to as dispersion liquid Y). Then, 10 g of Dispersion Y was added to 400 g of polyester varnish WH-4060, and the mixture was stirred and dispersed to obtain a resin composition.

Comparative Example 3 1 part of 10 g of low molecular weight polyethylene (number average molecular weight 4000)
Dispersion in 00 g of xylene gave a dispersion (hereinafter referred to as dispersion Z). 400 g of polyester varnish WH-4060
10 g of Dispersion Z was added and dispersed by stirring to obtain a resin composition.

[Test example]

Using the resin compositions obtained in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3, the diameter was 0.4 m according to the baking conditions shown below.
The copper wire of m was applied and baked to produce an enamel wire.

Coating method: Base (WH-4060): Dice 5 times (7 times only in case of single coating of Comparative Example 1) Top ground (resin composition obtained in each Example or Comparative Example): Dice 2 times Baking conditions Baking Furnace: Horizontal electric heating furnace (furnace length: 3 m) Furnace temperature: Inlet / outlet = 450 ° C / 500 ° C Linear velocity: 30 m / min The characteristics of the obtained enamel wire coating were tested by the following methods, and the results are shown in Table 1. Shown in.

Flexibility test: According to JIS C3003, 8.1 (1).

Pinhole test: According to JIS C3003, 6.

Dielectric breakdown voltage: According to JIS C3003, 11 (2).

Reciprocating wear test: According to JIS C3003, 10.1 for 1 day.

Static friction coefficient: The coefficient of static friction between enameled wires is measured. The measurement method uses an electric wire slip tester manufactured by Toyo Seiki Co., Ltd. Stretch out in a divergent manner, and place another sled in which two wires are wound in parallel so that they intersect with the four wires, and gradually incline it from the horizontal position to set the slid start angle. I read it on the tangent scale. The load of the sled is
It was set to 100g.

Dispersion stability: 40 g of the resin composition was placed in a 50 cc glass bottle and allowed to stand in a thermostat at 40 ° C. for one week, and then the separated state of the contents was observed.

As is apparent from Table 1, the enameled wires obtained in the examples of the present invention have a smaller coefficient of static friction, excellent slipperiness, and a better appearance than those of the comparative examples, and further, the dispersion of the resin composition. Excellent stability.

[Effects of the Invention] The resin composition for electrical insulation of the present invention has good dispersion stability and excellent workability for baking, and an enamel wire produced using the same has excellent appearance and excellent slipperiness. Harsh winding,
It can be applied to processing and assembly work.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunori Okada 4-13-1, Higashimachi, Hitachi City, Ibaraki Prefecture, Hitachi Chemical Co., Ltd. Yamazaki Factory (56) Reference JP-A-1-264106 (JP, A)

Claims (3)

[Claims] 1. A low molecular weight polyethylene having 0.1 to 10 parts by weight of (A) a partially saponified ester wax and (B) a number average molecular weight of 5,000 or less with respect to 100 parts by weight of a resin content of a synthetic resin coating for an enamel wire.
A resin composition for electrical insulation, which comprises 0.1 to 10 parts by weight. 2. The resin composition for electrical insulation according to claim 1, wherein the synthetic resin paint for enameled wire is a polyester resin paint. 3. An insulated wire obtained by applying and baking the resin composition for electrical insulation according to claim 1 on a conductor directly or through another insulator.