JPS62113412A - Manufacture of electric insulating coil - Google Patents

Abstract

PURPOSE:To permit a taping with an insulating tape having a good workability and to repeatedly use the impregnating resin not being blended with a curing accelerating agent for a long time by a method wherein the main insulating layer is formed by winding the insulating tape using an addition product consisting of a 2-ethyl-4-methyl imidazole and a specific tertiary carboxylic acid glycidyl ester as its curing accelerating agent and after a predrying is performed, a resin consisting of an acid anhydride curing agent and an epoxy resin is impregnated in the main insulating layer, which is cured. CONSTITUTION:An addition produce consisting of a 2-ethyl-4-methyl imidazole and a tertiary carboxylic acid glycidyl ester represented by a formula (a) (R is saturated fatty acid of C8-C10) is used as a curing accelerating agent, a main insulating layer is formed by winding an insulating tape made to hold this product and a cycloaliphatic epoxy resin. After a predrying is performed, a resin being mainly constituted with an acid anhydride curing agent and an epoxy resin is impregnated in the main insulating layer and the main insulating layer is cured. A high-viscosity or low-melting point solid substance obtainable by denaturizing a polyolefin epoxy resin is suitable as the cycloaliphatic epoxy resin to be used along with the curing accelerating agent, and a polyglycidyl ether, an epoxy novolak and so on are used as the epoxy resin to be blended in an impregnating resin.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is an electrical insulator in which a main insulating layer formed by winding an insulating tape containing a curing accelerator around a conductor is impregnated with a resin and cured. This invention relates to a method of manufacturing a ring.

[Prior art and its problems]

Epoxy resin compositions that use acid anhydride as a curing agent have low viscosity, and the cured product has excellent electrical, mechanical, and thermal properties, so it is used as an impregnating agent when manufacturing electrical insulation wire. It is suitable for

However, although a resin composition consisting of an epoxy resin and an acid anhydride has a sufficiently long pot life, it has a disadvantage in that it has poor curability and takes a long time to cure.

When commonly used curing accelerators such as tertiary amines, imidazoles, and carzenate metal salts are used to improve such low curing properties, the drawback is that the pot life is impaired. be.

In order to solve such problems with pot life and curability, it is desirable to use a so-called latent curing accelerator, but no one having sufficiently satisfactory latent properties has yet been found.

Therefore, as an alternative method, it has been conventionally practiced to hold the curing accelerator in the insulating layer of the coil, which is the object to be impregnated, without adding the curing accelerator to the impregnating resin.

In this way, in order to retain the curing accelerator in the coil insulating layer, there are two methods: forming an insulating layer around the outer periphery of the coil and then immersing it in a solution of the curing accelerator and drying it, and an insulating tape that holds the curing accelerator in advance. Created.

There is a method of wrapping the curing accelerator around the outer circumference of the coil, but the latter method is superior in terms of uniformity of the curing accelerator held and ease of operation. Something like this is required.

(1) Excellent curability.

(2) It must not be volatilized during preliminary drying performed before impregnating the resin.

(3) Good adhesion between the laminated mica foil and the backing material.

(4) The wrapping of the insulating tape should have appropriate flexibility so that it maintains good properties.

Assuming that the requirements of (1) and (2) above are satisfied,
There is an example of using an addition product of an imidazole compound and an organic metal salt, but most of the curing accelerators obtained by this method have properties close to solids, and the adhesive strength is low, as shown in (3) and (+) above. It doesn't meet the requirements.

[Means for solving problems]

The present invention has been made to eliminate the drawbacks of the conventional method as described above, and is characterized by the above-mentioned (1).
As a curing accelerator that satisfies all the requirements of , (2)', (3), and (4), 2-ethyl-4-methylimidazole and tertiary carbon expressed by the following formula % (saturated fatty acid of FLFiC8C+o) are used. A main insulating layer is formed by using an addition product with acid glycidyl ester and an insulating tape holding an alicyclic epoxy resin, and after pre-drying, acid anhydride curing is applied to the main insulating layer. The process involves impregnating and curing a resin whose main components are a chemical agent and an epoxy resin.

The above curing accelerator satisfies the requirements (1) and (2) above, but alone cannot satisfy the requirements (3) and (4), so an alicyclic epoxy resin is used to compensate for this. It is something.

In other words, the insufficient adhesive strength of the curing accelerator is compensated for by adding a high-viscosity alicyclic epoxy resin, and furthermore, the alicyclic epoxy resin hardly reacts with imidazole compounds at around room temperature, so that insulation is achieved. It maintains the initial flexibility of the tape without losing it.

The amount of the curing accelerator retained in the insulating layer is 0.00 parts per 7100 parts of the impregnated resin made of the epoxy resin and acid anhydride.
A range of 5 to 3.0 parts is desirable.

The reason for this is that if the amount is less than 0.5 parts, sufficient curing accelerating ability cannot be obtained, and if it is more than 3 parts, there is a risk of deteriorating the physical properties of the cured epoxy resin.

As the alicyclic epoxy resin used together with the above-mentioned curing accelerator, it is preferable to use a high-viscosity or low-melting-point solid obtained by modifying a polyolefin-based epoxy resin synthesized by a peroxidation method for the above-mentioned reasons.

The epoxy resin and acid anhydride that are blended into the impregnated resin are not particularly limited. Epoxy resins include polyglycidyl ether obtained from polyhydric phenol, polyhydric alcohol, and epichlorohydrin, and epoxy resin obtained from Nozerak type phenol and epichlorohydrin. Epoxy resins such as epoxy nodilac, polyolefin epoxy resins synthesized by peroxidation method, polyglycidyl esters obtained from epichlorohydrin, 7-clopentadiene oxide, cyclohexene oxide, or hexahydrophthalic acid, etc. alone or in combination A combination of the above is used, and the acid anhydrides include maleic anhydride, tetrahyphthalic anhydride, hexahydrophthalic anhydride, dodecenylsuccinic anhydride, methylendomethylenetetrahibiro-7talic anhydride, and methyltetrahydrophthalic anhydride. Phthalic acid, methyl hexahydrophthalic anhydride, and the like are used.

The present invention will be specifically explained below using examples.

〔Example〕

First, equimolar amounts of 2-ethyl-4-methylimidazole and Cardura E (manufactured by Yuka Shell Epoxy Co., Ltd.: tertiary carboxylic acid glycidyl ester) were heated at about 60°C in a reaction vessel.
to obtain a very viscous addition product,
A glass cloth-backed laminated mica tape was prepared using a mixture of this and Finerex 310C (alicyclic epoxy resin manufactured by Fine Polymers Co., Ltd.) in 4 to 6 parts as an adhesive. The thickness of this tape was 0.13 m, the amount of adhesive was 6.5%, and as a result of a flexibility test (according to method B) according to JIS C2116, it showed a flexibility of 1552, which is optimal for taping work. Furthermore, when this mica tape assembly was stored in a refrigerator for 30 days and then subjected to similar measurements, the result was 1702, which showed very little change.

Next, the laminated mica tape produced as described above was
The coil was wound three times with a 772 lamp to form the main insulating layer and further wrapped once with a polyester film tape Q172 lamp, and then dried at 150°C for 10 hours.
100 parts of R332 (epoxy resin manufactured by Dow Chemical) and H
N2200 (Acid anhydride curing agent 3 manufactured by Hitachi Chemical Co., Ltd.)
Impregnated with 80 parts of resin under vacuum pressure and heated at 150°C for 1
An insulated coil was produced which was cured for 0 hours.

On the other hand, for comparison, both Epicoat 828 and Ebiko 1004C were combined with a laminated mica tape whose adhesive was a mixture of 4 to 6 epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd. and the impregnated tape used in the above example. An insulated coil was produced under the same conditions as in the above example using an impregnated resin in which 0.2 part of 61B (modified amine manufactured by Certilny) was added as a curing accelerator.

The outermost polyester film of the insulated coil according to the present invention and the insulated coil of the comparative example obtained as described above was removed, and the dielectric voltage junction (tan δ)-temperature characteristics were measured. The results are shown in FIG.

As is clear from this figure, the insulated coil according to the present invention is
It shows almost the same characteristics as the insulated coil of the comparative example, and the curing accelerator held in the composite mica tape was heated to 150℃ x 1.
This shows that the impregnated resin was completely cured without volatilization even after pre-drying for 0 hours.

Further, since the impregnated resin used in the examples of the present invention does not contain a curing accelerator, the increase in viscosity during storage is very small and it can be used repeatedly over a long period of time.

〔Effect of the invention〕

As described above, the main insulating layer is formed by winding the insulating tape holding the curing accelerator according to the present invention, and after pre-drying, the resin is impregnated with an acid anhydride and an epoxy resin and cured. According to the method for manufacturing electrical insulating wires, taping can be performed with insulating tape that is easy to work with, and the impregnated resin, which does not contain a curing accelerator, can be used repeatedly over a long period of time, and the electrical insulating wires have excellent properties. can be obtained.

[Brief explanation of drawings]

FIG. 1 is a dielectric loss tangent-temperature characteristic diagram of an example of the present invention and a comparative example.

Claims (2)

[Claims] (1) As a curing accelerator, 2-ethyl-4-methylimidazole and tertiary carboxylic acid glycidyl ester represented by the following formula ▲ Numerical formula, chemical formula, table, etc. ▼ (R is a saturated fatty acid of C_8-C_1_0) Using the addition product, the main insulating layer is formed by winding this with an insulating tape holding an alicyclic epoxy resin, and after pre-drying, the main insulating layer is coated with an acid anhydride curing agent and an epoxy resin. A method for manufacturing an electrically insulated wire wheel, characterized by impregnating and curing a resin containing as a main component. (2) The method for manufacturing an electrically insulating coil according to claim 1, characterized in that a laminated mica tape is used as the insulating tape.