JPH0239042B2 - GOSEIJUSHIHIFUKURIIDOSENOJUSURUTORANSU - Google Patents

Description

[Detailed description of the invention]

The present invention particularly relates to a transformer that produces less whirring noise during operation and has improved mechanical strength at the lead wire outlet. Conventionally, for the purpose of electrical insulation, heat dissipation during operation, and absorption of humming noise generated by electrical vibration, the entire transformer has been immersed in an insulating composition for insulation treatment. In recent years, as transformers have become smaller and lighter and their usage conditions have become more severe, insulation treatments that are particularly effective in reducing the whining noise are replacing the unsaturated polyester resins and polybutadiene resins that have traditionally been used for this type of treatment. There is an increasingly strong demand for the development of materials. As such a material, the general formula An unsaturated polyester resin using the unsaturated carboxylic acid represented by as the carboxylic acid component has been developed, and because it has excellent adhesion and toughness, it can be expected to be effective in reducing humming noise. However, the film of the above resin becomes extremely hard after curing, so transformers using lead wires coated with synthetic resins such as vinyl chloride resin, which easily become brittle at low temperatures, are also insulated at the lead wire exits. In this case, there was a drawback that cracks were likely to occur in the vinyl chloride resin coating at the outlet when exposed to vibrations or other external forces in cold weather. The present invention was made in order to eliminate such drawbacks, and consists of an ester oligomer obtained by reacting a carboxylic acid component mainly composed of unsaturated carboxylic acid represented by the above general formula with a polyhydric alcohol, and a plant-based ester oligomer. This transformer is characterized by being insulated with a composition made of a mixture of unsaturated polyester resin modified with natural oils and fats, etc., which reduces the generation of whining noise and improves the mechanical strength of the lead wire outlet. This is what we are trying to provide. In the present invention, (a) General formula used for producing the ester oligomer (A) The unsaturated carboxylic acid represented by is a polymerization product obtained by heating reaction of cyclopentadiene and 1,3-pentadiene (commercially available products include QN-0301 manufactured by Nippon Zeon Co., Ltd.) and anhydride. Esterification or addition reaction of α,β-unsaturated dicarboxylic acids such as maleic acid (and water), fumaric acid, itaconic acid, and citraconic acid or their anhydrides using an acid catalyst such as a Lewis acid as necessary. It can be obtained by In the present invention, in addition to these unsaturated carboxylic acids, the carboxylic acid component (a) includes phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid,
A small amount of saturated dicarboxylic acid such as sebacic acid or succinic acid can also be used in combination. In addition, (b) polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3 or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, Erythritol etc. In the present invention, these polyhydric alcohols and the above-mentioned carboxylic acids are used in an equivalent ratio of approximately 1:0.7 to 1, a known inhibitor is added as necessary, and these are subjected to a condensation reaction by a solvent method or a melt method. Obtain an ester oligomer. In the present invention, mixed with the above ester gomer
The modified unsaturated polyester resin (B) uses unsaturated carboxylic acids such as maleic anhydride and fumaric acid, and saturated carboxylic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, and adipic acid as acid components, and uses soybean oil, It is obtained by modifying vegetable oils and fats such as linseed oil, olive oil, and coconut oil, or their fatty acids. In the curable resin composition used in the present invention,
2 to 20 parts by weight (hereinafter simply referred to as parts) of the ester oligomer (A). and 98 to 80 parts of the modified unsaturated polyester resin (B) are mixed, and the blending amount is limited to this range for the following reason. In other words, the amount of ester oligomer (A) is 2
If the amount of the modified unsaturated polyester resin (B) exceeds 98 parts, the strength such as adhesion of the cured layer obtained from the composition will be poor; If the amount of the modified unsaturated polyester resin (B) exceeds 20 parts and is less than 80 parts, the cured layer will become too hard and have poor flexibility, and the lead wire exit part will become stiff due to mechanical stress in cold weather. This is because cracks are likely to occur in the insulating layer such as vinyl chloride resin, which is not preferable in either case. In order to insulate a power transformer weighing, for example, 0.5 to 3 kg using a curable resin composition containing the above-mentioned amounts of each component, first the transformer is
After preheating and drying in a furnace at 100 to 120℃,
The transformer heated to ~60°C is immersed in a curable resin composition containing a curing agent for 3 to 10 minutes at normal pressure or in vacuum, and then placed in a furnace at 100 to 120°C for several hours to cure the resin. Perform curing and drying. Here, the hardening agents include peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, di-tertiary butyl peroxide, lauroyl peroxide, cumene hydroperoxide, tertiary-butyl peroxide, cobalt, copper, manganese, etc. , metal soaps such as lead, and curing accelerators such as tertiary amines are also used. In the present invention, in order to cure the resin layer after insulation treatment, in addition to redox curing using a combination of a peroxide curing agent and a curing accelerator, ultraviolet curing using a known photosensitizer is used. or far infrared curing. Next, examples of the present invention will be described. Examples 1 to 3 First, ester oligomers () to () and modified unsaturated polyester resins () to () were produced as follows. (Production of ester oligomer) 1 196 parts of maleic anhydride, 50 parts of water, QN-0301
After reacting 550 parts of hydroquinone and 0.04 parts of hydroquinone at 140°C under a nitrogen gas stream for 3 hours, 91.2 parts of propylene glycol was added and the temperature was gradually raised to 180°C.
A dehydration condensation reaction was carried out at a temperature of 20°C, and when the oxidation temperature reached 20°C, the mixture was cooled to 120°C and 0.04 part of hydroquinone was added to obtain an ester oligomer (). 2 Maleic anhydride 196 parts, water 50 parts, QN-0301
After reacting 550 parts of hydroquinone and 0.04 parts of hydroquinone at 140℃ for 3 hours under a nitrogen gas stream, 127 parts of diethylene glycol was added and the temperature was gradually raised to 180℃.
A dehydration condensation reaction was carried out, and when the acid value reached 20, the mixture was cooled to 120°C and 0.04 part of hydroquinone was added to obtain an ester oligomer (). 3 Maleic anhydride 196 parts, water 50 parts, QN-0301
After reacting 550 parts of hydroquinone and 0.04 parts of hydroquinone at 140°C for 3 hours under a nitrogen gas stream, 183 parts of propylene glycol and 148 parts of phthalic anhydride were added and the temperature was gradually raised to carry out a dehydration condensation reaction at 180°C.
When the acid value reaches 25, cool it and use hydroquinone.
0.04 part was added to obtain estergomer (). (Production of modified unsaturated polyester resin) 1. 90 parts of soybean oil fatty acid, 69 parts of maleic anhydride, 44 parts of phthalic anhydride, 70 parts of propylene glycol,
30 parts of glycerin was placed in a reaction vessel, and the temperature was gradually raised under a stream of nitrogen gas to perform a dehydration condensation reaction at 200°C. When the acid value reached 20, it was cooled and 0.05 part of hydroquinone was added to obtain the resin (). Ta. 2 Flaxseed oil fatty acid 95 parts, maleic anhydride 66 parts,
66 parts of adipic acid and 103 parts of ethylene glycol were charged, and a dehydration condensation reaction was carried out at 200°C under a stream of nitrogen gas. When the acid value reached 20, it was cooled and 0.05 part of hydroquinone was added to obtain a resin (). 3 112 parts of soybean oil, 18 parts of glycerin, lead monoxide
0.04 part was charged and the transesterification reaction was carried out at 240°C for about 1 hour under a nitrogen gas stream. After cooling to 130℃, add 86 parts of maleic anhydride,
Add 91 parts of isophthalic acid and 91 parts of ethylene glycol, perform a dehydration condensation reaction at 200°C, and reduce the acid value to 20.
The mixture was cooled and 0.05 part of hydroquinone was added to obtain a resin (2). Next, the ester oligomers () to () obtained in this way and the modified unsaturated polyester resins () to () are blended in the composition shown in the table, and 100 parts of styrene and 0.5 parts of manganese naphthenate are added to this, and a curing agent is added. Using each resin composition obtained by adding 1 part of tertiary butyl perbenzoate and stirring and mixing, the weight of 2 parts was added under the following conditions.
Kg power transformer was insulated. That is, after preheating and drying the transformer in a furnace at 110°C, the transformer was immersed in a composition kept at room temperature at about 50°C for 5 minutes at normal pressure, and then heated at 110°C.
It was heated and cured for 2 hours. In addition, in order to examine the crack resistance of the vinyl chloride resin coated lead wire, test pieces shown in FIGS. 1 and 2 were prepared. That is, as shown in FIGS. 1 and 2, 1
Bend 10 UL1015 (manufactured by Sumitomo Electric Co., Ltd.) vinyl chloride resin-coated lead wires 2 on a mm-thick iron plate 1 so that the lead wires 2 sandwich the iron plate 1, and apply adhesive tape 3 to both sides of the iron plate 1. Glue both ends of the lead wire 2, and then attach a 1mm thick iron plate 1 to the bottom of the lead wire 2.
and fixed it using a clip. Next, the whole was immersed in the resin composition for 10 minutes and then heated at 110°C for 2 hours to harden the immersion layer and obtain a test piece. Comparative Examples 1 to 6 100 parts of styrene and manganese naphthenate were added to each of the ester oligomers () to () and the modified unsaturated polyester resins () to ().
A transformer was insulated in the same manner as in the example using a resin composition obtained by adding 0.5 part of tertiary butyl perbenzoate and further adding 1 part of tert-butyl perbenzoate and stirring and mixing. In addition, test pieces for crack resistance testing of vinyl chloride resin-coated lead wires were prepared. Next, a humming sound was heard when a voltage of 1.1 times the rated voltage was applied to the primary side of the transformer, which had been insulated in Examples and Comparative Examples, by applying the ear or a stethoscope to the transformer. As a result, the humming noise of the transformers obtained in Examples was almost the same as that of the transformers obtained in Comparative Examples 1 to 3, and was much smaller than that of the transformers of Comparative Examples 4 to 6. . In addition, the level of whining noise was measured using a vibration tester. The measurement results are shown in the table below. Furthermore, the test pieces prepared in Examples and Comparative Examples were placed in a low temperature bath at -10°C and -15°C for 1 hour, then taken out, and the lead wires were immediately bent to an angle of 180°C. I counted the number of lines. The results are expressed as number of cracks/10 and are shown in the table below.

[Table] *Unit (G): Vibration acceleration As is clear from the above examples, the transformer of the present invention has a low level of whining noise both during energization and during switching. In addition, since the flexibility of the lead wire coated with vinyl chloride resin or the like at low temperatures is less likely to be impaired, there is an advantage that the occurrence of cracks at the lead wire exit portion during cold weather is greatly reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of test pieces prepared in Examples and Comparative Examples of the present invention, and FIG. 2 is a top view thereof. 1... Iron plate, 2... PVC resin coated lead wire, 3... Adhesive tape.

Claims (1)

[Claims] 1 (A), (B) The following general formula (However, in the formula, X represents an α, β-unsaturated hydrocarbon group having 2 or 3 carbon atoms, and n represents 2 or 3. The same applies hereinafter.) Mix 2 to 20 parts by weight of an ester oligomer obtained by reacting an acid with (B) a polyhydric alcohol, and (B) 98 to 80 parts by weight of an unsaturated polyester resin modified with vegetable oil or its fatty acid. 1. A transformer having a synthetic resin-coated lead wire, characterized in that the lead wire is insulated with a curable resin composition comprising: