JPH0243327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a method for insulating electrical equipment such as electrical equipment wires, and particularly relates to a solvent-free thermosetting resin impregnated into wires under vacuum conditions, and The present invention relates to a method for insulating electrical equipment in which a photocurable resin is combined to prevent the resin from decreasing in viscosity when heated and flowing out from the wire.

Conventionally, the general method for insulating electrical equipment wires is to wrap insulation tape or the like around the wire to form an insulating layer, impregnate it with thermosetting resin under vacuum, and then harden the resin by heating for insulation treatment. The method is adopted.

There are many advantages to impregnating an object to be insulated, such as a wire, with resin using this insulation treatment method. Part 1
The first is to improve moisture resistance and stain resistance in order to prevent moisture, dust, etc. from entering the inside of the wire insulation layer. Furthermore, since there are no voids inside the insulating layer, generation of electrically harmful corona can be suppressed. Furthermore, another advantage is that thermal conductivity can be improved and temperature rises can be kept low. However, in order to effectively exhibit these advantages, it is important that the resin is sufficiently and completely impregnated into the insulating layer so that there are no voids. To this end, it is necessary to prevent the resin impregnated under vacuum from flowing out of the insulating layer during the process of complete curing.

In addition, conventional insulation treatment methods have the drawback of causing undesirable effects in terms of health and safety and pollution due to the diffusion of curing agents, catalysts, monomers, etc. generated during the curing of the thermosetting resin.

The present invention eliminates the above-mentioned drawbacks and completely cures the thermosetting resin impregnated into the insulating layer of the insulated object without flowing out from the insulating layer, suppresses corona generation without creating voids or voids, and improves electrical characteristics. The purpose of the present invention is to provide an insulation treatment method for electrical equipment that can provide excellent insulation treatment.

Another object of the present invention is to provide a method for insulating electrical equipment that can prevent adverse effects on health and safety and pollution caused by volatilization of curing agents, catalysts, monomers, etc. generated during the curing process of thermosetting resins. The purpose is to

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The present invention involves a process of immersing the electrical equipment wire, which is an object to be insulated, in a photocurable resin while preventing the resin injection port, and adhering the photocurable resin to the surface of the wire insulation layer, and adhering it to the surface of the wire insulation layer. The photocurable resin is irradiated with ultraviolet rays to cause a photopolymerization and crosslinking reaction to form a three-dimensional network structure at least on the surface of the photocurable resin, and the resin injection port is opened and thermosetting is performed under vacuum. A method for insulating electrical equipment, comprising a step of impregnating a resin and a step of curing unreacted portions of a thermosetting resin and a photocurable resin by heating.

The present invention will be explained in more detail. The electrical equipment coil described here as one type of electrical equipment is not particularly limited, and may be any of the field winding of a rotating machine, the winding of a stationary equipment such as a transformer, etc. However, as long as it has an insulating layer and can be impregnated with resin, it may be either a single winding or a winding after being incorporated into a device.

The present invention will be described in detail below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes an electric wire ring, which is an insulated object on which an insulating layer 2 is formed by being insulated in advance with an insulating tape or the like. Adhesive tapes 3a and 3b are pasted to appropriate locations on the electric wire ring 1 to close portions that will be used as resin injection ports, which will be described later. 4 is an immersion container filled with a photocurable resin 5, and the electric coil 1 is immersed in this photocurable resin 5. The photocurable resin 5 used here preferably has a viscosity that does not penetrate into the inside of the insulating layer 2 of the electric coil 1, although it depends on the material and density of the insulating tape applied to the insulating layer 2. Something around 10 to 100 poise is desirable.

Next, the electric wire 1 immersed in the photocurable resin 5
is taken out from the immersion container 4, and as shown in FIG. 2, is irradiated with ultraviolet light using an ultraviolet lamp 6 to cause a photopolymerization and crosslinking reaction on the surface of the photocurable resin 5, so that at least the surface of the photocurable resin 5 has a three-dimensional network structure. Form the body.

Next, as shown in FIG. 3, the adhesive tapes 3a and 3b attached to the electric wire ring 1 are peeled off, and the blocked resin injection ports 7a and 7b are opened. In FIG. 3, reference numeral 8 denotes an impregnating container, and the electric wire 1 immersed in the photocurable resin 5 is placed in the impregnating container 8, and then stored together with the impregnating container 8 in a vacuum container 9 by appropriate means. Fixed. The air in the vacuum container 9 is gradually drawn out by the operation of an external supply/exhaust device 11 connected via valves 10a and 10b, the pressure is reduced, and a vacuum state is created. In parallel with this evacuation work, the thermosetting resin 13, which is the impregnating resin in the impregnating resin tank 12 provided at the top of the vacuum container 9, flows down from the ceiling of the vacuum container 9 into the impregnating container 8 by opening the valve 14 and is impregnated. Container 8
The inside is filled with thermosetting resin 13.

Therefore, as time passes, the electric wire 1 in the impregnation container 8 is exposed to resin injection ports 7a and 7b under a vacuum condition.
The thermosetting resin 13 is impregnated into the insulating layer 2. The impregnating resin used here is a solvent-free thermosetting resin, and is preferably of the same type as the photocurable resin 5.

When the thermosetting resin 13 is sufficiently impregnated into the insulating layer 2 of the electric coil 1 through this impregnation step, air is again supplied into the vacuum container 9 from the air supply/exhaust device 11 to restore atmospheric pressure.

Next, the electric wire 1 impregnated with the thermosetting resin 13 is taken out from the impregnation container 8 and the vacuum container 9, and the fourth
As shown in the figure, the thermosetting resin 13 is placed in a constant temperature bath 15 and hardened by heating.

What is important here is that the thermosetting resin 13 impregnated under vacuum is cured by heating, but the unreacted photocurable resin 5 of the same type as the thermosetting resin 13 is also cured at the same time. This means that no interface is created between the curable resin 5 and the thermosetting resin 13. Therefore, if resins of completely different types are used for the photocurable resin 5 and the thermosetting resin 13, there is a risk that an interface will be created between the resins and peeling may occur during operation. This is not desirable because it may not be possible to obtain a cured product. In any case, the impregnated thermosetting resin 13 and the unreacted photocuring resin 5 are cured by heating, but no matter how much the viscosity decreases when the temperature is raised, the outermost layer is a three-dimensional photocurable resin 5. Since a network structure is formed, the thermosetting resin 13 does not leak out at all.

As the thermosetting resin used in the present invention, conventionally used polyfunctional prepolymers, curing agents and monomers used in combination therewith, and the like can be used without particular limitation. Typical examples of these include epoxy resins, which include bisphenol A-type glycidyl ether, alicyclic epoxy resins, and novolak-type epoxy resins, all of which contain amine hardeners, acid anhydride hardeners, and It can be used in appropriate combination with a reactive diluent and a curing accelerator.

It goes without saying that a wide variety of amine curing agents can be used in combination with the epoxy resin, but latent curing agents such as samine complexes of boron tetrafluoride and dicyandiamide are also effective.
Similarly, the acid anhydride curing agents include, for example, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, methyltetrahydrophthalic anhydride, loleic anhydride,
One or a mixture of two or more polybasic acid anhydrides such as dodecylsuccinic anhydride and pyromellitic anhydride are effective.

Similarly, examples of the reactive diluent include glycidyl methacrylate, allyl glycidyl ether, butanediol diglycidyl ether, etc., but these reactive diluents may be added in small amounts to the resin when the viscosity of the resin is high and it is difficult to impregnate the insulating layer. Used when added to reduce viscosity and facilitate impregnation.

Further, as the curing accelerator, for example, tertiary amines such as benzyldimethylamine, tri-dimethylaminomethylphenyl and its salts, a-methylbenzyldimethylamine, or transition metals such as zinc octylate and cobalt octylate are used. Examples include salts or complexes, but these curing accelerators are usually 100 parts (parts by weight, same below) of epoxy resin.
Generally, a sufficient effect is obtained by adding about 0.1 to 5 parts.

On the other hand, as the photocurable resin used in the present invention, a polymer or prepolymer having two or more unsaturated groups in the molecule can be used alone or in combination with a vinyl monomer as necessary, but in particular, the photocurable resin at the end of the molecule may be Those having a polymerizable crosslinking group are preferred, for example, methacrylic acid and acrylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, propylene glycol dimethacrylate, polyethylene glycol dimethacrylate, or bis(β-hydroxyl). Acrylic acid and methacrylate of unterminated hydroxyl group type polyester oligomers such as dimethacrylate of ethyl)hexahydrophthalate, dimethacrylate of bis(β-hydroxylethyl)phthalate, and dimethacrylate of bis(β-hydroxylethyl)isophthalate. Examples include acid esters. It is preferable to add a small amount of sensitizer to these photocurable resins, such as quinone compounds such as anthraquinone and naphthoquinone, carboxyl compounds such as benzoin, and disulfide compounds such as diphenyl disulfide. By using a sensitizer that responds sharply, the photopolymerization and crosslinking reaction of the photocurable resin can be carried out sufficiently. In addition to these sensitizers, peroxides and the like may be used in combination if necessary.

Next, specific examples in which the present invention was actually tested will be described.

Example 1 0.05mm thick aramid insulating tape is wrapped 1/2 times three times, then 0.13mm thick Aras tape is wrapped 1/2 times.
Multivalent β
Cover the resin injection port and immerse in a photocurable resin bath in which 100 parts of hydroxyacrylate (trade name: Lipoxy E-1000, manufactured by Showa Kobunshi Co., Ltd.) and 20 parts of glycidyl methacrylate and 3 parts of benzoin methyl ether as a sensitizer are uniformly mixed. did. Next, take out the wire from the photocuring resin tank and use a high pressure mercury lamp (80w/
cm) and irradiated with ultraviolet light for several minutes. Furthermore, open the resin injection port and place under vacuum 100 parts of bisphenol diglycidyl ether with an epoxy equivalent of approximately 190 (trade name Epicote 828, manufactured by Ciel Chemical Co., Ltd.), 75 parts of an acid anhydride curing agent (trade name HN2200, manufactured by Hitachi Chemical Co., Ltd.), and octyl. Impregnated with thermosetting resin mixed uniformly with 2 parts of zinc oxide and heated at 150°C for 5 hours at 110°C.
The mixture was dried for 10 hours and then slowly cooled to room temperature.

Example 2 Using the same dry transformer wire as used in Example 1, the thermosetting resin was replaced with a uniform mixture of 100 parts of Epikote 828, 75 parts of phthalic anhydride, and 2 parts of zinc octylate. The same operations as those performed in Example 1 were performed.

As a result of the above, as shown by line a in Figure 5, the room temperature and
A heat cycle was performed at 220°C, and a constant current was applied at each cycle to measure the temperature rise. As a result, the temperature rise remained almost constant even after 500 heat cycles, and stable values were obtained with no peeling observed in the insulating layer.

As explained above, according to the method for insulating electrical equipment of the present invention, the first step is to immerse the object to be insulated on which an insulating layer has been formed into a photocurable resin, and the photocurable resin of the object to be insulated is exposed to ultraviolet light. a second step of causing a photopolymerization and crosslinking reaction by irradiation; a third step of impregnating the object to be insulated with a thermosetting resin under vacuum; and an unreacted portion of the thermosetting resin and photocurable resin of the object to be insulated. The thermosetting resin impregnated into the object to be insulated does not leak or flow out, and therefore the insulating layer of the object to be insulated has electrical performance without voids or voids. It is possible to produce excellent electrical equipment wires. In addition, by using a thermosetting resin of the same type as the photocurable resin, the photocurable resin is further irradiated with ultraviolet rays to cause a photopolymerization and crosslinking reaction only on the surface, and when the thermosetting resin is heated and cured, the photocurable resin remains intact. By curing the reaction portion as well, no interface is created between the photocurable resin and the thermoset resin, making it possible to form an integrated insulating layer without worrying about peeling. Furthermore, since the surface of the photocurable resin has a three-dimensional network structure, there is no undesirable impact on health, safety, and pollution caused by the volatilization of the curing agent catalyst and monomer that occur during the curing process of the thermosetting resin. It can be prevented.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the step of dipping an electric wire in a photocurable resin in one embodiment of the present invention, and FIG.
The figure is a perspective view showing the photopolymerization and crosslinking reaction process using ultraviolet irradiation, FIG. 3 is a sectional view showing the impregnation process in a vacuum container, FIG. 4 is a sectional view showing the heating process, and FIG. FIG. 3 is a characteristic diagram showing data based on a specific experimental example of the invention. 1...Electric wire ring, 2...Insulating layer, 3a, 3b...
... Adhesive tape, 4 ... Immersion container, 5 ... Photocurable resin, 6 ... Ultraviolet lamp, 7a, 7b ... Resin injection port, 8 ... Impregnation container, 9 ... Vacuum container, 11
...Air supply and exhaust system, 12...Impregnated resin tank, 13
... Thermosetting resin, 15 ... Constant temperature bath.

Claims (1)

[Claims] 1. A first step of immersing an insulated object on which an insulating layer has been formed into a photocurable resin, a second step of subjecting the photocurable resin of the insulated object to a photopolymerization crosslinking reaction by irradiating ultraviolet rays, and A third step of impregnating the photocurable resin with a thermosetting resin of the same type as the photocurable resin under vacuum, and a fourth step of heating and curing the unreacted portion of the photocurable resin together with the thermosetting resin of the object to be insulated. A method for insulating electrical equipment consisting of: