JPS58214225A - Method of producing resin coated electric device - 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 The present invention provides weather resistance and tracking resistance by coating the conductors and windings of insulators used outdoors, transformers, current transformers, transformers, etc. with a special epoxy resin. The present invention relates to a method of manufacturing an electrical device with excellent performance.

Generally, alicyclic diglycidyl ester type epoxy resin is used as an epoxy resin for outdoor use because it has excellent weather resistance and tracking resistance. The same applies to electrical equipment.

When used for outdoor electrical equipment, alicyclic diglycidyl ester type epoxy resins are used together with alicyclic acid anhydrides and fillers.

However, the reaction rate of conventional coating resins, which are mixtures of alicyclic diglycidyl ester type epoxy resins and alicyclic acid anhydrides, increases rapidly at high temperatures, resulting in large curing shrinkage of the resulting cured product. In addition, at high temperatures, the reaction rate is sensitive to slight temperature differences, so there are local differences in the degree of hardening of the cured product, which can result in cracks, sink marks, or voids in the resin layer, and damage to the resin and conductor. This has the disadvantage that peeling occurs between the parts and the winding parts, which adversely affects the electrical characteristics of the electrical device.

For this reason, a method of performing the curing reaction at a low temperature has conventionally been adopted. However, this low-temperature method also requires a long period of time for curing, and since it is not completely cured at low temperatures, it requires a two-step curing process of curing at low temperatures and then curing at higher temperatures.1 This reduces workability and productivity. decrease,
Because the mixture of resin and filler remains in a fluid state for a long time, the filler settles during that time, resulting in a difference in filler content in the cured product.Based on this difference in filler content. Differences in the coefficient of thermal expansion can cause cracks in electrical equipment, and in particular unevenness in the filler content on the surface of electrical equipment is caused by outdoor exposure to sunlight, rain, and dirt. To promote unevenness in the roughness of the surface, uneven surface roughness tends to cause concentration of the surface electric field, leading to tracking, localized concentration of erosion, and often creeping flash. There were drawbacks such as being a cause of death.

The aim of the invention is to eliminate the above-mentioned drawbacks. In other words, the curing reaction at high temperatures is mild, and a uniform coating resin layer is formed without cracking, sink marks, peeling, voids, or filler sedimentation, resulting in a resin-coated electrical device with excellent weather resistance and tracking resistance. It provides a manufacturing method.

(A) Alicyclic diglycidyl ester type epoxy resin
1. A mixture consisting of an alicyclic acid anhydride, quartz powder, a silane coupling agent, and an accelerator is (B) heated and reacted in advance so that the epoxy equivalent is 1.1 to 1.4 times the initial value, 1
A resin mixture with a viscosity of 10 to 50 voids at 00 to 120°C is prepared, and (C) this is injected into a mold in which a conductor or winding is set and heated and cured at 100 to 140°C to form a resin-coated electrical It is characterized by manufacturing a device.

The chemical structure of diglycidyl hydrogenated bisphenol A used in the present invention is represented by the following formula.

In the present invention, diglycidyl hydrogenated bisphenol A is used in an amount of 10 to 100 parts per 100 parts of alicyclic diglycidyl type epoxy resin.
60 copies are used. If the amount used is less than 10 parts, the curing reaction cannot be moderated, while if it exceeds 30 parts, the curing reaction time becomes longer, productivity decreases, and sedimentation of the filler occurs, resulting in non-uniformity. It becomes a coating resin layer, which is not preferable.

The alicyclic diglycidyl type epoxy resin used in the present invention has, for example, hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydroisophthalic acid dicrycidyl ester, hexahydroterephthalic acid diglycidyl ester as a constituent unit. Examples of alicyclic acid anhydrides include hexahydrophthalic anhydride, tetrahydrophthalic anhydride, 3-(4-)methyltetraphthalic anhydride, and 3-(4-)methylhexahydrophthalic anhydride. Examples include 7-talic anhydride.

As the quartz powder, for example, silica or fused quartz powder is used, and as the silane coupling agent, for example, β
-(6,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, etc. are used.

Further, as the first accelerator, for example, benzyldimethylamine, tris(dimethylaminomethyl)phenol, etc., boron trifluoride ethylamine complex compound, triethanolamine boron acid [,2-ethyl-4-ethylimidazole, -Imidazoles such as methylimidazole are used.

In the present invention, calcium carbonate, 7 oxide
Appropriate amounts of fillers such as aluminum, aluminum hydroxide, talc, clay, pigments, dyes, plasticizers, flame retardants, etc. may be added.

The present invention will be specifically explained below with reference to Examples and Comparative Examples.

Examples 1-3 Alicyclic diglycidyl epoxy resin (Araldai) OY
184, manufactured by Ciba Geigy) 100 parts, diglycidyl hydrogenated bisphenol A to parts (Example 1), 20
parts (Example 2) or 30 parts (Example 6), 100 parts of hexahydroheptalic anhydride, silica@(average particle size 1.5μ)
rn) 500 parts, r-glycidoxypropyltrimethoxysilane 6 parts and benzyldimethylamine 0.5 part were mixed and then heated and reacted at 105°O for 1 hour to obtain an epoxy resin part from which silica powder was removed. The equivalent weight is the initial value (55
0) 1.62 times (Example 1), 1.19 times (Example 2)
), 1.15 times (Example 6), viscosity at 105 ° O is 22 voices (Example 1), 15 voices (Example 2),
A resin mixture of 15 voices (Example 6) was injected into a predetermined mold and heated at 160° a for 24 hours to cure, resulting in a coated resin length of 500 mm as shown in FIG.

7 langes & 220mm bushings were made.

Comparative Example 1 100 parts of Araldite (OY 184), 90 parts of hexahydrophthalic anhydride, 450 parts of silica powder, 2.7 parts of γ-glycidoxypropyltrimethoxysilane and 0.5 parts of benzyldimethylamine were heated at 10500 for 10 minutes. A bushing was produced in the same manner as in Example 1, except that the mixture was mixed by mouth.

Comparative Example 2 A bushing was prepared in the same manner as in Comparative Example 1, except that heating and mixing was performed at 80°O for 10 minutes, and the heat curing conditions in the mold were first at 80°0 for 4 hours and then at 150°O for 20 hours. was created.

In the above Examples and Comparative Examples, the silica powder filling rate of the upper pleat part during curing in the mold was measured, and the difference between that value and the theoretical filling rate calculated from the blended amount was expressed in weight%. This is shown in Table 1 as the amount of sedimentation.

Table 1 No cracks, sink marks, or voids were observed in the bushings obtained in Examples 1 to 6, but in the bushings obtained in Comparative Example 1, the circumference was already broken at the root of the 7 flange in the mold after curing. Cracks in the direction were observed, and although no cracks were observed in the bushing of Comparative Example 2, a portion with a low silica powder filling rate was observed in the folds at the upper part of the mold, and the resulting bushing The silica powder filling rate on the surface was non-uniform.

In addition, the bushings obtained in Examples 1 to 6 did not deteriorate in appearance, mechanical properties, and tracking resistance even after being subjected to a test equivalent to 10 years of outdoor exposure using a weatherometer. The tracking index was 600 V or more.

In addition, FIG. 2 shows the viscosity characteristics of the resin mixtures obtained in the examples and comparative examples taken at the temperature during heating and mixing, which were separated at the time of injection into the mold.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of bushings produced in Examples and Comparative Examples. FIG. 2 is a graph showing viscosity characteristics of resin mixtures. (Main symbols on the drawings) (1): Bushing (2): Coating resin (3): Conductor agent Shin Kuzuno - (1 other person)

Claims (1)

[Claims] (1) When producing an electrical device coated with epoxy resin by injecting epoxy resin into a mold in which a conductor or winding is set and curing it, (4) alicyclic diglycidyl ester type epoxy resin, A mixture consisting of 10 to 60 parts by weight of diglycidyl hydrogenated bisphenol A, alicyclic acid anhydride, quartz powder, a silane coupling agent, and an accelerator per 100 parts by weight of the epoxy resin is heated and reacted in advance to form an epoxy resin. A resin mixture with an equivalent weight of 1.1 to 1.4 times the initial value and a viscosity of 10 to 50 voids at 100 to 120°C, (0) is poured into a mold and heated at 100 to 140°C. A method for producing a resin-coated electrical device characterized by curing.