JP2008103105A - Resin composition for electrical insulation, and manufacturing method of electric equipment insulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for electrical insulation capable of softening a varnish film and demonstrating excellent cured object characteristics such as electric insulation and excellent stability same as or better than a conventional liquid type resin composition, and a manufacturing method of an electric equipment insulator. <P>SOLUTION: This is a resin composition for electrical insulation which contains as an essential material an unsaturated polyester (A) using alcohol having α,β-unsaturated dibasic acid and one or more hydroxyl group as an essential component, a reactant diluent (B) having an unsaturated group, and a xylene-formaldehyde resin (C), and a manufacturing method of an electric equipment insulator in which an electric equipment is covered and cured by the resin composition for electrical insulation containing a polymerization initiator and a stabilizer in the resin composition for electrical insulation is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin composition for electrical insulation and a method for producing an electrical equipment insulator, and more specifically, an electrical insulation resin composition mainly composed of an unsaturated polyester resin and a xylene / formaldehyde resin, and the electrical insulation resin composition. The present invention relates to an electrical device that is impregnated, immersed, and insulated by using an object. More specifically, it has a flexible cured film and cures in a short time without deteriorating the impregnation of coils for electrical equipment such as motors, transformers, armatures (rotors), and stators (stators). The present invention relates to a resin composition for electrical insulation and a method for producing an electrical equipment insulator.

  Unsaturated polyester compositions consisting of unsaturated polyester and crosslinkable monomers are harmonized in terms of mechanical, electrical and thermal properties, workability, economy, etc. It is used for This resin composition is widely used as an impregnation varnish for motors, transformers and the like because of its excellent characteristics and workability even for electrical insulation.

The requirements for the impregnating varnish for transformer include low-temperature and short-time curing and reduction of solvent volatilization from the varnish (no solvent).
In a low-frequency transformer such as a power transformer, noise is generated by magnetostriction or magnetic force when energized due to iron core vibration or coil vibration due to electromagnetic force.

In order to prevent this noise, it is known that the occurrence of vibration itself is prevented by increasing the fixing force of the unsaturated polyester resin for insulation treatment, depending on the structure of the device. Moreover, since the iron core is used, the provision of rust prevention and high heat resistance is also required.
In addition, with the recent shift to digital home appliances, there is a tendency for electrical appliances for home appliances to use high-frequency transformers that can be reduced in size from low-frequency transformers that use large iron cores.

  This high-frequency transformer uses ferrite instead of iron for the core portion. For this reason, when the adhesive strength of the varnish is increased, the cured product becomes harder, the stress on the ferrite core is increased, the core shift is induced, or the core portion is cracked and the electrical characteristics are deteriorated. .

As a method for solving this problem, first, it is necessary to soften the cured product by changing the varnish composition.
However, in the above method, the composition of the varnish composition is changed, the varnish curability is deteriorated, and the productivity is lowered.

As a method of softening without changing the varnish composition, for example, there is a method of adding a plasticizer described in Patent Document 1 and Patent Document 2. However, even with this method, if a plasticizer is added too much, the curability of the resin composition is deteriorated or the adhesive force of the cured resin is reduced.
Japanese Patent Laid-Open No. 11-185531 JP 2000-178424 A

In view of such problems, the present invention is capable of softening a varnish film in a resin composition for electrical insulation and a method for manufacturing an electrical device using the same as an impregnating varnish for a high-frequency transformer that is considered to become a mainstream transformer in the future. Further, the present invention provides a resin composition for electrical insulation that can exhibit cured product characteristics such as good electrical insulation properties equal to or better than conventional liquid type resin compositions and good stability.
Moreover, this invention provides the manufacturing method of the electrical equipment insulator using this resin composition for electrical insulation.

The present invention relates to an unsaturated polyester (A) using an α, β-unsaturated dibasic acid and an alcohol having one or more hydroxyl groups as essential components, a reactive diluent (B) having an unsaturated group, and xylene. -It relates to the resin composition for electrical insulation containing formaldehyde resin (C) as an essential material.
Moreover, this invention relates to the said resin composition for electrical insulation whose molecular weight of unsaturated polyester (A) is the range of 1000-10000.

The present invention also provides the resin for electrical insulation, comprising 50 to 200 parts by weight of a reactive diluent (B) having an unsaturated group in the molecule with respect to 100 parts by weight of the unsaturated polyester (A). Relates to the composition.
Moreover, this invention relates to the said resin composition for electrical insulation formed by containing 0.1-20 weight part of xylene formaldehyde resin (C) with respect to 100 weight part of resin compositions for electrical insulation.

  The present invention also relates to a method for producing an electrical equipment insulator, wherein the electrical equipment is coated with an electrical insulation resin composition containing a polymerization initiator and a stabilizer on the electrical insulation resin composition and cured. About.

The resin composition for insulating electrical equipment according to the present invention is excellent in the flexibility of the varnish cured product, and therefore can provide a film in which cracks and the like are unlikely to occur even when stress is applied.
In addition, since the viscosity and surface drying properties of the resin composition are the same as those of conventional products, it can be used in a wide range of impregnation work methods, and air drying properties and electrical insulation properties that are equivalent to or better than conventional liquid type resin compositions. In addition, it is possible to provide a highly reliable manufacturing method of an electrical equipment insulator that exhibits cured product characteristics such as adhesion and good stability.

  In the present invention, the unsaturated polyester (A) using an α, β-unsaturated dibasic acid and an alcohol having one or more hydroxyl groups as essential components includes an acid component and an alcohol containing an unsaturated dibasic acid as essential components. It is obtained by reacting components, and if necessary, modified components.

As the unsaturated dibasic acid, maleic anhydride, maleic acid, fumaric acid and the like are used, and these may be used alone or in combination.
As the acid component, in addition to the unsaturated dibasic acid described above, a saturated acid and a diester of this saturated acid lower alkyl may be used in combination.

  For example, terephthalic acid diesters such as monomethyl terephthalate and lower alkyl diesters of terephthalic acid such as dimethyl terephthalate are used. Further, isophthalic acid, adipic acid, phthalic acid, sebacic acid and the like can also be used.

  Saturated acids include saturated dibasic acids such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, tetrahydrophthalic acid, hexahydrophthalic anhydride, hexahydrophthalic acid, adipic acid, and sebacic acid. Can be mentioned. As a diester of a saturated acid lower alkyl, for example, dimethyl terephthalate is used. These may be used alone or in combination.

  Furthermore, edible oil fatty acids such as soybean oil fatty acid, linseed oil fatty acid and tall oil fatty acid can be used in combination. The amount of the unsaturated acid is preferably selected in the range of 50 to 90 equivalent% in the total acid component.

  As the alcohol component, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,3-butanediol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol and the like are used, and these may be used alone or in combination. May be. Examples of the modifying component used as necessary include linseed oil, soybean oil, tall oil, dehydrated castor oil, coconut oil, dicyclopentadiene, and cyclopentadiene.

  The number average molecular weight of the unsaturated polyester (A) used in the present invention (measured by gel permeation chromatography and converted using a standard polystyrene calibration curve, the same applies hereinafter) is preferably 1000 to 10,000, 5000 is more preferable. If it is less than 1000, the curability and resin cured product properties of the resin composition tend to be extremely inferior, and if it exceeds 10,000, the viscosity is too high and the workability of impregnation into a transformer or the like tends to deteriorate.

  As a manufacturing method of unsaturated polyester (A) used for this invention, it can be based on a conventionally well-known method. For example, it occurs when an α, β-unsaturated dibasic acid, which is an essential component, and only an alcohol having one or more hydroxyl groups, or a polybasic acid component or a polyhydric alcohol component are used in combination and subjected to a condensation reaction, and both components react. The process proceeds while removing condensed water out of the system. The total alcohol component is preferably used in the range of 1 to 2 equivalents relative to 1 equivalent of the total acid component.

  Removal of the condensed water out of the system is preferably carried out by natural distillation or reduced pressure distillation through an inert gas. In order to promote the distillation of the condensed water, a solvent such as toluene or xylene can be added to the system as an azeotropic component. The progress of the reaction can be generally known by measuring the amount of distillate produced by the reaction, quantifying the functional group at the end, and measuring the viscosity of the reaction system.

  The reaction temperature for carrying out the synthesis reaction is preferably 150 to 250 ° C. For this reason, a glass, stainless steel or the like is selected as the reaction apparatus, and a stirring apparatus, a fractionation apparatus for preventing distillation of alcohol components due to azeotropy of water and alcohol components, and raising the temperature of the reaction system. It is preferable to use a reactor equipped with a heating device, a temperature control device for the heating device, and the like.

  The pressure inside the reactor adjusted to carry out the polycondensation reaction in the synthesis can proceed without any problem even at normal pressure, but the reaction is accelerated by increasing the boiling point of the polyhydric alcohol by pressurization. be able to. In this case, it is preferable to carry out in the range of normal pressure to 0.1 MPa.

  Examples of the reactive diluent (B) having an unsaturated group used in the present invention include styrene, vinyl toluene, α-methyl styrene, tertiary butyl styrene, divinyl benzene, various acrylic esters, various methacrylic esters, and various allyls. Examples include esters and various allyl ethers. These can be used alone or in combination of two or more.

  The use amount of the unsaturated polyester (A) and the reactive diluent (B) having an unsaturated group is 100 parts by weight of the unsaturated polyester (A) and the reactive diluent (B) having an unsaturated group. It is preferable to be in the range of 50 to 200 parts by weight. When the amount is less than 50 parts by weight, the viscosity of the resulting resin composition is too high and not only thickly adheres to the transformer surface, but also tends to deteriorate the internal permeability. Moreover, if the reactive diluent (B) having an unsaturated group is added in excess of 200 parts by weight, the varnish viscosity is too low, and a problem occurs that the resin deposit that has penetrated inside flows out during heat curing. Tend.

  The xylene / formaldehyde resin (C) used in the present invention is preferably a resol type resin obtained by reacting xylene and formaldehyde in the presence of an alkali catalyst such as sodium hydroxide, ammonia or triethylamine. Examples of commercially available xylene / formaldehyde resins include Generalite 30, Generalite 50, Generalite 100 manufactured by General Petrochemical Co., Ltd., Nikanol L, Nikanol LL, Nikanol LLL manufactured by Mitsubishi Gas Chemical Co., Ltd., straight, Alkyl-modified types, novolac types, and epoxy types can also be used.

  The amount of the (C) component xylene / formaldehyde resin used in the present invention is 100 parts by weight based on the total amount of the reactive diluent having the unsaturated polyester (A) and the unsaturated group (B). Xylene / formaldehyde resin (C) is preferably 0.1 to 20 parts by weight, more preferably 1 to 15 parts by weight, and still more preferably 5 to 10 parts by weight. If the xylene / formaldehyde resin exceeds 20 parts by weight, the curing time of the resin composition will be prolonged, and it tends to be difficult to cure. Also. If the blending amount is less than 0.1 parts by weight, the resin composition tends to be insufficient in softening the cured film.

  Examples of the polymerization initiator used in the present invention include ketone peroxides, peroxydicarbonates, hydroperoxides, diacyl peroxides, peroxyketals, dialkyl peroxides, peroxyesters, alkylperesters. And the like.

  The amount of the polymerization initiator is determined according to each of the curing conditions and the aspects such as the appearance and characteristics of the cured resin product. In view of storage stability of the material and molding cycle, the content is preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight based on the total amount of the unsaturated polyester resin and the reactive diluent.

  Stabilizers used as necessary in the present invention include p-benzoquinone, hydroquinone, naphthoquinone, p-toluquinone, 2,5-diphenyl-p-benzoquinone, 2,5-diacetoxy-p-benzoquinone, p-tert-butyl. Catechol, 2,5-di-tert-butylhydroquinone, di-tert-butyl-p-cresol, hydroquinone monomethyl ether, 2,6-di-tert-butyl-4-methylphenol and the like can be mentioned.

  The blending amount is conveniently determined by the storage stability of the resin composition, the curing temperature and the curing time during actual machine processing, and the blending amount is usually 0.5 parts per 100 parts by weight of the resin composition. The amount is preferably not more than parts by weight, more preferably 0.01 to 0.1 parts by weight.

The resin composition for electrical insulation according to the present invention is suitable for insulating treatment of electrical equipment such as high-frequency transformers and switching transformers using ferrite because the resulting varnish film has flexibility.
The insulation treatment is performed by a method of immersing an electric device in the resin composition of the present invention for 2 to 20 minutes, then pulling up and heating at 80 to 150 ° C. for 1 to 3 hours to cure the resin composition.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited to these. In the examples, “parts” means “parts by weight” unless otherwise specified.
[Synthesis of Unsaturated Polyester (A-1)]
In a 3 liter flask equipped with a thermometer, a nitrogen blowing tube, a rectifying column and a stirrer, 1474 parts (11 moles) of dipropylene glycol, 498 parts (3 moles) of isophthalic acid, 392 parts (4 moles) of maleic anhydride ), Tetrahydrophthalic anhydride (456 parts, 3 moles) and hydroquinone (0.22 parts) were added and heat condensed at 210 ° C. for 10 hours to synthesize an unsaturated polyester (A-1) having an acid value of 21.5.

[Synthesis of unsaturated polyester (A-2)]
In a 3 liter flask equipped with a thermometer, a nitrogen blowing tube, a rectifying column and a stirrer, 341 parts (5.5 moles) of ethylene glycol, 296 parts (2.0 moles) of phthalic anhydride, 196 maleic anhydride Parts (2.0 mol), soybean oil fatty acid 560 parts (2.0 mol) and hydroquinone 0.24 parts were put into a four-necked flask and heat-condensed at 200 ° C. for 8 to 12 hours to give an acid value of 20.8. Unsaturated polyester (A-2) was synthesized.

[Preparation of unsaturated polyester resin compositions a-1 and a-2]
In 100 parts of the unsaturated polyester (A-1), 150 parts of styrene and 1.25 parts of 8% manganese naphthenate were stirred and dissolved to obtain an unsaturated polyester composition a-1.
In 100 parts of unsaturated polyester (A-2), 150 parts of styrene and 0.5 part of 8% manganese naphthenate were stirred and dissolved to obtain unsaturated polyester composition a-2.

Examples 1-4
Unsaturated polyester composition a-1 with xylene / formaldehyde resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name Nicanol LL) and 1,1-di (tertiary butyl peroxy) cyclohexane (manufactured by Kayaku Akzo, product) Nominal Trigonox 22E-70) was blended in the proportions shown in Table 1 to prepare a resin composition.
About the obtained resin composition, drying time and the hardness of hardened | cured material were evaluated by the test method of a postscript.

Comparative Examples 1-3
1,1-di (tertiary butyl peroxy) cyclohexane was blended with the unsaturated polyester composition a-1 in the proportions shown in Table 1, and the drying time and the hardness of the cured product were evaluated by the test methods described later.

Examples 5-8
Except having changed unsaturated polyester composition a-1 into a-2, operation similar to Examples 1-4 was performed, and the resin composition was produced. About the obtained resin composition, drying time and the hardness of hardened | cured material were evaluated by the test method of a postscript.

Comparative Examples 4-6
Except having changed unsaturated polyester composition a-1 into a-2, operation similar to Comparative Examples 1-3 was performed, and the resin composition was produced. About the obtained resin composition, drying time and the hardness of hardened | cured material were evaluated by the test method of a postscript.

Test method (resin composition viscosity and surface drying time)
It measured according to the test method of the viscosity (varnish viscosity) and drying time (air drying property) of JIS C2105.
[Hardness of cured product]
A cured product is produced by heating the resin composition to a metal petri dish having a diameter of 60 mm at 15 g or less at 110 ° C. for 1.5 hours. This cured product was kept at 23 ° C. and measured using a Shore D hardness meter.
The obtained results are shown in Tables 1 and 2.

Claims (5)

  An unsaturated polyester (A) using an α, β-unsaturated dibasic acid and an alcohol having one or more hydroxyl groups as essential components, a reactive diluent (B) having an unsaturated group, and a xylene / formaldehyde resin ( A resin composition for electrical insulation comprising C) as an essential material.   The resin composition for electrical insulation according to claim 1, wherein the unsaturated polyester (A) has a molecular weight in the range of 1000 to 10,000.   The resin composition for electrical insulation according to claim 1 or 2, comprising 50 to 200 parts by weight of a reactive diluent (B) having an unsaturated group in the molecule with respect to 100 parts by weight of the unsaturated polyester (A). object.   4. The resin composition for electrical insulation according to claim 1, comprising 0.1 to 20 parts by weight of xylene / formaldehyde resin (C) with respect to 100 parts by weight of the resin composition for electrical insulation. object.   An electrical device is coated with an electrical insulation resin composition containing a polymerization initiator and a stabilizer on the electrical insulation resin composition according to any one of claims 1, 2, 3 or 4, and cured. Manufacturing method of electrical equipment insulation.