JPH06240023A - Electrical insulating coil and its production - Google Patents

Abstract

PURPOSE:To provide a highly reliable electrical insulating coil which is used for a rotating electric machine, stationary electrical equipment, etc., and is excellent in heat resistance, water resistance and flame retardancy. CONSTITUTION:A wound electrical insulating coil 3 for electrical equipment has an insulating layer 2 made by impregnating with a varnish comprising an acid-anhydride-curing epoxy resin composition containing an epoxy compound having a naphthalene ring skeleton represented by the formula in an amount of at least 50wt.% of all the epoxy compounds and curing the varnish to form an integral part of the coil. This technique can provide an electrical insulating coil used for a rotating electric machine and having excellent heat resistance, flame retardancy and water resistance, can reduce the size of an electric machine and can improve the reliability and safety.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine for a vehicle, a general industrial rotating electric machine, and an insulating wire loop of a static electric device such as a reactor, and particularly, an electric device which is required to have heat resistance, water resistance and flame retardancy. The present invention relates to an electric insulated wire suitable for the above and its manufacturing method.

[0002]

2. Description of the Related Art The demand for smaller and lighter rotary electric machines for vehicles, general-purpose rotary electric machines for industrial use, and static electric equipment has become stronger and stronger.
Insulation of the electrically insulated coil used is also required to have high voltage and high heat resistance.

In these devices, it is required that the insulating material of the insulating coil be more flame-retardant from the viewpoint of safety such as disaster prevention. However, until now, in these devices, when a flame retardant was added to the impregnating varnish, the viscosity became high, impregnating property was impaired, and many voids and the like were generated in the insulating layer, resulting in good insulating properties and heat resistance. There are problems such as not being able to. In the equipment in which the details of the insulating layer need to be impregnated with varnish, the method of directly incorporating the flame retardant into the varnish is not generally performed.

On the other hand, as an insulating impregnating varnish for an electric insulating wire wheel, a system in which an epoxy resin is cured with anhydrous acid has a low viscosity as a varnish, and it has excellent impregnating workability and handling workability. It is widely used because of its various characteristics.

Further, in this impregnated varnish, various measures are taken to make the viscosity as low as possible in order to improve the impregnating property. However, there has been a problem that the insulating wire loop of a rotating electric machine impregnated and cured with a low-viscosity anhydride-curable epoxy varnish is inferior in long-term heat resistance and flame retardancy. Also, hydrogen atoms of the benzene nucleus of the epoxy are partially replaced with bromine atoms to impart flame retardancy, but in this case also the viscosity is not necessarily low, and it cannot be said that the heat resistance is sufficient. There is a problem that toxic gas is generated during combustion.
Further, most of these rotary electric machines are often used outdoors and are exposed to wind and rain, so that the insulating layer is required to have excellent water resistance.

[0006]

As an epoxy resin having excellent moisture resistance and heat resistance, for example, JP-A-1-268 can be used.
Japanese Patent No. 712 discloses a naphthalene ring skeleton. However, when manufacturing insulated coils of rotating electrical machines, no consideration has been given to lowering the viscosity of varnishes, which is an important issue when considering the workability of varnish impregnation. It was

As described above, in the prior art, an anhydride-cured epoxy resin system having a low viscosity and a good impregnating workability is used as a varnish for insulating coil of electric equipment, and has heat resistance, flame retardancy and water resistance. There was nothing.

An object of the present invention is to provide an insulating wire loop for an electric device which uses a low-viscosity impregnated varnish and is excellent in heat resistance, flame retardancy and water resistance, and a method for producing the same.

[0009]

Means for Solving the Problems The gist of the present invention for solving the above problems is as follows.

An acid anhydride cured epoxy resin composition in which the insulating layer of the electrically insulated coil of the wound electric device contains 50% by weight or more of the epoxy compound of the naphthalene ring skeleton represented by the following formula [1] based on the total epoxy compounds. An electrically insulated wire loop that is made by impregnating and curing a varnish consisting of.

[0011]

[Chemical 5]

The varnish for impregnating the insulating layer of the electrically insulated wire of the present invention is a system in which a naphthalene ring skeleton epoxy resin having good heat resistance and water resistance and excellent flame retardancy is cured with anhydrous acid. A varnish having a composition that does not impair the flame retardancy, heat resistance, and water resistance of the cured product was used by lowering the viscosity in order to improve the impregnation workability.

The epoxy resin component may be a naphthalene ring skeleton epoxy resin alone as long as the viscosity of the varnish can be impregnated to 30 poises or less, preferably 20 poises or less, but if the oxygen index is 25 or more and the viscosity is satisfied, other You may use together various epoxy which has a skeleton.

However, from the viewpoint of viscosity and flame retardancy, it is desirable that the naphthalene ring skeleton epoxy resin represented by the above formula [1] is blended in an amount of 50% by weight or more based on the total amount of epoxy resin. Further, the total amount of the naphthalene ring skeleton epoxy resin represented by the above formulas [1], [2] and [3] is preferably at least 70% by weight based on the total amount of the epoxy resin.

The acid anhydride curing agent is used in an amount of 0.7 to 1.3 (equivalent ratio), preferably 0.9 to 1.1, relative to the epoxy compound.
(Equivalent ratio) It is preferable to mix. The acid anhydride is preferably a monofunctional liquid acid in terms of viscosity, but a polyfunctional one may be used as long as the viscosity can be satisfied. Generally, when a polyfunctional anhydride is added, the viscosity increases, but the heat resistance tends to improve.

Further, various curing accelerators generally used in the epoxy / anhydrous system can be used.

[0017]

[Function] As a resin for forming an insulating layer of an insulating coil of a rotating electric machine or the like, a naphthalene ring skeleton epoxy resin which does not impair the flame retardancy of a cured product and reduces the viscosity of a varnish is used as an acid curing agent. By using the curing system, the impregnating property of the varnish into the insulating layer is improved, and it is possible to provide an electric device having excellent heat resistance and water resistance.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples. Table 1 shows the epoxy resin, the curing agent, the curing accelerator and the like used in each example and comparative example.

[0019]

[Table 1]

[Examples 1 to 9 and Comparative Examples 1 to 9] Samples for measuring the characteristics of the cured resin plate were prepared by the following methods.

0.5% by weight of 2P based on the total weight of the varnish
Z-CN (curing accelerator) is mixed with MHAC-P (anhydrous acid curing agent) and heated to 50 to 80 ° C. and stirred to completely dissolve it. Next, 2P is added to each epoxy composition shown in Tables 2 and 3.
A predetermined amount of MHAC-P in which Z-CN is dissolved is mixed and uniformly mixed with stirring.

This was placed in a test tube and a mold that had been subjected to a mold release treatment, and was heat-cured in a dryer under predetermined conditions. The curing conditions are as follows.

Condition (a) 120 ° C./5 hr → 150 ° C.
/ 5 hr → 170 ° C./5 hr Condition (b) 120 ° C./5 hr → 150 ° C./5 hr → 1
70 ° C / 5hr → 230 ° C / 5hr

[0024]

[Table 2]

[0025]

[Table 3]

Next, FIG. 1 shows the method for producing the electrically insulated coil of the present invention.
It will be explained based on.

Varnishes having the respective compositions shown in Tables 1 and 2 to which no curing accelerator is added are prepared. Next, a conductor 1 is prepared by winding a plurality of conductor wires having a double glass insulating layer for inter-stage insulation. Further, a heat-resistant film-backed mica tape (thickness 0.13 mm) and a glass plain weave tape (thickness 0.10 mm), which are laminated with a binder resin, are immersed in a 2% by weight 2PZ-CN solution (solvent: methanol). Then, only the solvent is dried and volatilized to cure accelerator 2PZ-CN.
Make a tape with attached.

Next, the heat-resistant film-backed mica tape is wound around the outside of the conductor 1 by half, and the glass plain weave tape is wound around the conductor by half, and the insulating layer 2 is formed. did. Table 2 (Examples 1 to 9), Table 3
The varnishes of the respective compositions shown in (Comparative Examples 1 to 9) were vacuum impregnated and cured under the above condition (a) to fabricate the electrically insulating coil 3.

When the pot life of the impregnated varnish itself is taken into consideration, it is preferable to impregnate the tape side with the curing accelerator in advance as described above. I don't mind.

The various characteristics of the impregnated varnish were measured by the following methods. The measurement results are shown in Tables 2 and 3.

Varnish viscosity: 25 ° C. by B-type viscometer
Measured by.

Glass transition temperature: using TMA apparatus,
The temperature was increased at 5 ° C./min and the coefficient of thermal expansion greatly changed (the test piece of the resin plate alone was used).

Oxygen index: Measured by a flammability test method for polymer materials according to the oxygen index method of JIS K7201 (indicating the flammability of a resin plate alone, the higher the value, the harder it is to burn).

Tensile strength retention rate: 10 at 250 ° C.
Retention ratio to the initial value of the tensile strength after heating for a day (a No. 1 dumbbell-shaped test piece was cut out from the insulating layer of the insulating loop, and the tensile strength in the direction perpendicular to the winding direction was measured at room temperature with a tensile tester).

Weight loss rate: Weight loss rate after heating at 270 ° C. for 10 days (50 mm after cutting out the insulating layer of the insulating wire ring)
X 50 mm test piece).

Water absorption rate: Weight change rate after immersion in water at room temperature for 10 days (25 mm × 2 obtained by cutting out the insulating layer of the insulating wire ring)
Measured with a 5 mm test piece).

From the results shown in Table 2, the varnish used in this example has a high glass transition temperature of the resin after curing even though it has a low viscosity and is excellent in flame retardancy. In addition, the insulating layer of the electric insulating wire wheel impregnated with the varnish has both heat resistance and water resistance,
It can be seen that it is superior to that of the comparative example shown in Table 3.

[0038]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to manufacture an insulating coil of electric equipment which is required to have heat resistance, flame retardancy and water resistance
It greatly contributes to downsizing of equipment and improvement of reliability and safety.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional perspective view of an electrically insulated coil.

[Explanation of symbols]

 1 ... Conductor, 2 ... Insulating layer, 3 ... Electrically insulating coil.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H01F 41/12 C H02K 3/30 7346-5H 15/12 D 8325-5H // C08L 63:00 8830-4J

Claims (6)

[Claims] 1. An acid-cured epoxy resin composition, wherein the insulating layer of an electrically insulated coil of a wound electric device contains the naphthalene ring skeleton epoxy compound represented by the formula [1] in an amount of 50% by weight or more based on all epoxy compounds. An electrically insulated coil characterized in that a varnish consisting of is impregnated and cured to be integrated. [Chemical 1] 2. The naphthalene ring skeleton epoxy compound represented by the formulas [1], [2] and [3] is used as the insulating layer of the electric insulating coil of the wound electric device, and the total epoxy compound is 70.
An electrically insulated coil characterized in that it is impregnated with a varnish made of an acid anhydride-cured epoxy resin composition containing not less than wt% and cured to be integrated. [Chemical 2] 3. A method for producing an electrically insulating coil of an electric device having an insulating layer and wound, wherein the naphthalene ring skeleton epoxy compound represented by the formula [1] is a total epoxide compound as a varnish impregnating the insulating layer. A method for producing an electrically insulated coil, which comprises impregnating an acid-curable epoxy resin composition containing 50% by weight or more, and integrally heating and curing. [Chemical 3] 4. A naphthalene ring represented by the formula [1], [2] and [3] as a varnish impregnating the insulating layer in a method for producing an electrically insulating coil of an electric device having an insulating layer and wound. The skeleton epoxy compound is impregnated with an acid anhydride cured epoxy resin composition containing 70% by weight or more of all epoxy compounds,
A method of manufacturing an electrically insulated coil that is characterized by heating and hardening together. [Chemical 4] 5. The impregnated varnish has a viscosity of 30 poise or less and is cured by heating at 170 ° C. to 230 ° C. for 3 hours or more, and the cured product has a glass transition temperature of 160 ° C. or more and an oxygen index of 25 or more. The method for producing an electrically insulated wire according to claim 3 or 4, comprising an acid-cured epoxy resin composition. 6. The method for producing an electrically insulated coil according to claim 3, 4 or 5, wherein the impregnated varnish contains an acid anhydride curing agent in an amount of 0.7 to 1.3 (equivalent ratio) with respect to the epoxy compound.