JPH0124421B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel resin composition for coatings with excellent heat resistance. Specifically, the present invention relates to a solvent-free resin composition that is particularly useful as an electrically insulating coating. Currently, there are two types of electrical insulating paints commonly used: solution-type paints dissolved in organic solvents and solvent-free paints. The majority of heat-resistant paints used in electrical equipment of class H or higher are still solution-type paints, which release large amounts of organic solvents into the atmosphere during drying or baking, resulting in air pollution and hazardous work. In addition to arousing debate over environmental issues, the reality is that they have poor adhesion at high temperatures. In addition, unsaturated polyester resins, which have traditionally been used as solvent-free products, are somewhat satisfactory in terms of coating film performance such as curability, mechanical properties, and chemical properties, but they have low heat resistance. Currently, it is only used for products of class B or lower. Furthermore, the use of epoxy resins known as F-type solvent-free epoxy resins is restricted due to the toxicity of the polyamine that is the curing agent. In view of these circumstances, as a result of intensive studies, the present inventors have developed a resin composition for solvent-free paint that can be sufficiently used for high-temperature heat-resistant electrical equipment of Class F or higher and has excellent adhesion at high temperatures. He came to complete the thing. That is, a specific unsaturated alkyd component obtained by using a specific amount or more of tris(2-hydroxyethyl)isocyanurate, and diacrylate, triacrylate, dimethacrylate, and trimethacrylate of tris(2-hydroxyethyl)isocyanurate. A paint resin composition containing one or more selected from the group consisting of:
We have completed the present invention by discovering that it has particularly excellent properties such as storage stability, hardenability, heat resistance, adhesion strength, and compatibility with heat-resistant enameled wire. That is, the present invention relates to tris(2-hydroxyethyl) isocyanurate (hereinafter referred to as THEIC).
A polyhydric alcohol component (a) containing at least 30% by hydroxyl group equivalent, the polyhydric alcohol component
(a) An unsaturated fatty acid component having one or more double bonds in one molecule in a ratio of 0.5 to 1.5 mole per mole of trivalent or higher polyhydric alcohol contained in (b) and said polyhydric alcohol. Each component of the aromatic dibasic acid component (c) having a carboxyl equivalent ratio of 0.7 times or less to the total hydroxyl equivalent of the alcohol component (a) is subjected to a condensation reaction until the acid value of the product becomes 30 or less. An unsaturated alkyd ( A), tris (2
-Hydroxyethyl)isocyanurate-(meth)acrylate (B) (hereinafter referred to as THEIC-(meth)
It's called acrylate. ) and above as necessary
Polymerizable monomer copolymerizable with component (A) and component (B)
The present invention provides a resin composition for paint consisting of (C). Used in the present invention for unsaturated alkyd (A)
The amount of THEIC depends on the polyhydric alcohol component (a) used.
It is preferable that the hydroxyl equivalent is at least 30 equivalent % or more, preferably 50 equivalent % or more, and if it is less than 30 equivalent %, the expected effect cannot be obtained. Polyhydric alcohols other than THEIC that can be used include glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, and neopentyl glycol, and glycols such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. There are polyhydric alcohols with a valence of 3 or more. Examples of the unsaturated fatty acid component (b) having one or more double bonds in one molecule include drying or semi-drying oils such as soybean oil, linseed oil, tung oil, and castor oil, and soybean oil fatty acids and linseed oil. fatty acids, drying oils or semi-drying oils such as tung oil fatty acids, dehydrated castor oil fatty acids, etc., and one or two of these
More than one species is used. The amount used is preferably 0.5 to 1.5 mol per mol of trihydric or higher polyhydric alcohol contained in the polyhydric alcohol component (a) in terms of fatty acid. If it is less than 0.5 mol, the flexibility and processability of the obtained coating film will be poor, and if it is more than 1.5 mol, the heating loss of the coating film will be large, making it unfavorable in terms of heat resistance. Examples of the aromatic dibasic acid component (c) include phthalic acid, tetrabromophthalic acid, terephthalic acid, isophthalic acid, lower alkyl esters thereof, phthalic anhydride, tetrahydrophthalic anhydride, etc. Or two or more types are used.
Furthermore, trimellitic acid, pyromellitic acid, or anhydrides thereof may be substituted and used as part of the aromatic dibasic acid component (c). The amount of aromatic dibasic acid component (c) used is such that the ratio of carboxyl equivalents to the total hydroxyl equivalents of polyhydric alcohol component (a) is 0.7 times or less.
If the amount exceeds this, there will be insufficient hydroxyl groups to react with the unsaturated dibasic acid (e) necessary to obtain the unsaturated alkyd (A). In the present invention, the polyhydric alcohol component (a), the unsaturated fatty acid component (b), and the aromatic dibasic acid component (c) are subjected to a condensation reaction until the acid value of the product becomes 30 or less. The condensation product (d)
An unsaturated aliphatic dibasic acid (e) having a carboxyl group equivalent in a ratio equal to or less than the hydroxyl equivalent of (d) is reacted to form an unsaturated alkyd (A). Conventional reaction conditions can be applied to these reactions. Furthermore, in order to prevent gelation during the reaction, a polymerization inhibitor such as benzoquinone or hydroquinone may be added prior to the reaction or during the reaction. If the acid value of the condensation product (d) is high, exceeding 30, a resin composition for coating material with excellent performance cannot be obtained. Examples of the unsaturated aliphatic dibasic acid (e) include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, etc., and one or two of these
More than one species is used. The amount of unsaturated aliphatic dibasic acid (e) to be used is determined based on the amount of the condensation product (d).
The amount is such that the ratio of carboxyl group equivalents is less than or equal to the hydroxyl equivalents of . If the amount of unsaturated aliphatic dibasic acid (e) used exceeds this amount, it will be difficult to control the condensation reaction, and the acid component will increase, resulting in a large amount of acid component remaining after the reaction. It may impair the anti-corrosion ability of the paint. In addition, when the unsaturated aliphatic dibasic acid (e) contains an acid anhydride, the acid anhydride group corresponds to 2 equivalents of hydroxyl group. A more preferable amount of the unsaturated aliphatic dibasic acid (e) is based on the hydroxyl group equivalent of the condensation product (d).
The amount ranges from 0.99 to 0.50. The unsaturated alkyd (A) thus obtained,
THEIC diacrylate, triacrylate,
THEIC-(meth)acrylate (B) selected from the group consisting of dimethacrylate and trimethacrylate, and optionally these (A) components and
The coating resin composition of the present invention can be obtained from the component (B) and the polymerizable monomer (C) that can be copolymerized. The unsaturated alkyd (A) and THEIC-(meth)acrylate (B) are 20 to 95% by weight of the former and 5% by weight of the latter.
It is preferably 80% by weight (however, the total is 100% by weight). In addition, the polymerizable monomer (C) is
It is used in a ratio of 0 to 100 parts by weight based on a total of 100 parts by weight of the unsaturated alkyd (A) and THEIC-(meth)acrylate (B). Unsaturated alkyd (A) and
If the ratio of THEIC-(meth)acrylate (B) is out of the above range, the resulting coating resin composition will have poor viscosity and fluidity, and the cured coating film will have poor heat resistance. It may happen.
Furthermore, if the amount of the polymerizable monomer (C) exceeds the above range, the excellent performance of the coating resin composition of the present invention will not be exhibited. Examples of the polymerizable monomer (C) include styrene, vinyltoluene, divinylbenzene, diallyl phthalate, diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate, (meth)
Acrylic acid alkyl ester, benzyl (meth)
acrylate, furifuryl (meth)acrylate, dicyclopentenyl (meth)acrylate,
Dicyclopentenyloxyethyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, etc. can be used. The resin composition is selected depending on the various performances required for the paint resin composition, such as workability, fluidity, environmental workability, and economic efficiency. Unsaturated alkyd (A), THEIC-(meth)acrylate (B) and optionally polymerizable monomer (C),
They may be mixed in any order, and there are no particular restrictions on the mixing device. The coating resin composition of the present invention obtained in this way can be prepared by using conventional radical polymerization initiation examples, such as benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, di- Using t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide, t-butyl perbenzoate, etc., and optionally with a radical polymerization initiator, for example, cobalt octenoate, cobalt naphthenate, iron octenoate, manganese octenoate,
Organometallic salts such as vanadium octenoate, N,N-
By adding an accelerator such as organic amines such as dimethylaniline, curing can be carried out by methods such as room temperature curing, heating oven curing, infrared curing, and high frequency heating curing. Further, this coating resin composition can be cured by ultraviolet rays by adding a conventional photosensitizer such as benzophenone, benzoin, benzoin ethyl ether, dimethylacetophenone, etc. Alternatively, ultraviolet curing and heat curing can be used together. It is also possible to perform electron beam curing. The coating resin composition of the present invention may contain conventional additives such as leveling agents, antifoaming agents, thixotropes such as silicic anhydride fine particles, calcium carbonate, clay, glass powder, mica powder, microballoons, etc. Fillers, color pigments, flame retardants, stabilizers, etc. can also be used effectively. The resin composition for paint of the present invention can be used for motor parts,
In addition to being used as an insulating varnish for impregnation and dipping of electrical appliances such as transformer parts, it is also used as a resin for heat-resistant impregnation of various inorganic and organic fabric tubes and tapes, and for heat-resistant metals, heat-resistant engineering, etc. It is also useful as a paint for plastics or ceramics. The invention will be explained in more detail by the following examples. Example 1 560 g of soybean oil fatty acid, 522 g of tris(2-hydroxyethyl) isocyanurate, and ethylene glycol were placed in a 2-four-necked flask equipped with a thermometer, stirring device, condenser, distilled water receiver, and inert gas inlet tube. 30 g and 166 g of isophthalic acid were charged and stirred while heating with a mantle heater under a nitrogen stream. Gradually raise the temperature until it reaches 210-220℃,
The reaction proceeded while distilling the distillate out of the system, and when the acid value of the reactant reached 13, heating was stopped and the temperature was raised to 130°C.
cooled down to. followed by 200ppm hydroquinone and fumaric acid
116 g of the reactant was added, the temperature was raised to 180°C, and the reaction was carried out while distillate was distilled off. When the acid value of the reactant reached 20, heating was stopped. Obtained condensation product
0.01 part of hydroquinone per 50 parts, Tris (2
30 parts of triacrylate of (hydroxyethyl) isocyanurate, 5 parts of diallyl phthalate, and 15 parts of styrene were added and homogeneously mixed and dissolved to obtain a resin composition for coating (1). Add 1 part of t-butyl peroxy-2-hexanoate to 100 parts of this paint resin composition (1), place 1 g on an aluminum plate, and heat it for 1 hour at 100°C.
It was cured at ℃ for 2 hours to obtain a tough cured coating. This cured coating film was left in a thermostat at 250℃ and the weight loss rate was measured after 1 day and 10 days.The weight loss rate was 8% after 1 day and 14% after 10 days, and no abnormality was observed on the coating surface even after 10 days. It was found to be useful as a heat-resistant paint. In addition, when we conducted a metal plate coating test in accordance with the JIS C 2105 test method for solvent-free resins for electrical insulation, we obtained a smooth, strong coating with good adhesion, a dielectric breakdown voltage of 10kv/0.1mm, and a volume resistivity. rate 2×
10 ¹⁵ Ωcm and volume resistivity after water immersion test 1×
10 ¹⁴ Ωcm, and was effective as an electrical insulating paint. Comparative Example 1 0.01 part of hydroquinone, 30 parts of diethylene glycol dimethacrylate, 10 parts of diallyl phthalate, and 10 parts of styrene were added to 50 parts of the condensation product obtained in Example 1, and the mixture was uniformly dissolved. The weight loss rate due to continuous heating at 250℃ after curing under the following conditions was 17% after 1 day and 25% after 10 days.
%, indicating a weight loss approximately twice that of the cured product of Example 1. Comparative Example 2 Using the apparatus of Example 1, 296 g of phthalic anhydride,
Prepare 196g of maleic anhydride and 590g of dipropylene glycol and heat to 210-220℃ under nitrogen stream.
The mixture was dehydrated and condensed to obtain a condensation product with an acid value of 31. For 50 parts of this condensation product, hydroquinone
0.01 part of tris(2-hydroxyethyl)isocyanurate, 30 parts of triacrylate, 5 parts of diallyl phthalate, and 15 parts of styrene were added and uniformly dissolved, and a cured coating film was obtained under the same curing conditions as in Example 1. The weight loss rate of this cured coating film by continuous heating at 250°C was large, 14% after 1 day and 22% after 10 days. Example 2 Using the apparatus of Example 1, 560 g of soybean oil fatty acid,
522 g of tris(2-hydroxyethyl) isocyanurate, 25 g of ethylene glycol, and 216 g of isophthalic acid were charged and subjected to dehydration condensation in the same manner as in Example 1. When the acid value reached 11, 140 g of maleic anhydride was added to continue the reaction. , was condensed to an acid value of 18. For 50 parts of the obtained condensation product, 0.01 part of hydroquinone, 10 parts of triacrylate of tris(2-hydroxyethyl)isocyanurate,
A coating resin composition (2) was obtained by uniformly mixing and dissolving 10 parts of diallylisophthalate and 30 parts of diethylene glycol dimethacrylate. When this coating resin composition (2) was cured under the same conditions as in Generation 1, a tough film was obtained. In addition, a coating resin composition was applied using the twisted pair method onto a 1 mm diameter ISOMID wire, which was baked with ISOMID (manufactured by Nippon Schenectaday Co., Ltd., polyester imide paint), which is commercially available as a heat-resistant enameled wire of class H or higher. (2) is applied by impregnation,
Baked and hardened. The test piece obtained in this way
The deterioration of dielectric breakdown voltage over time was measured by continuous heating in a 250°C thermostat, and the results were as shown in the following table.

[Table] As is clear from the above table, the level of heat resistance over time of the H class enameled wire is sufficiently maintained, and the resin composition for paint of the present invention is also excellent in compatibility with the heat resistant enameled wire. It was sufficiently useful as an electrical insulation for H type.

Claims (1)

[Claims] 1. A polyhydric alcohol component (a) containing tris(2-hydroxyethyl) isocyanurate in a proportion of 30 equivalents or more based on hydroxyl group equivalents (a), a polyhydric alcohol containing trihydric or higher hydric alcohol contained in the polyhydric alcohol component (a) Unsaturated fatty acid component (b) having one or more double bonds in one molecule at a ratio of 0.5 to 1.5 moles to 1 mole
and each component of the aromatic dibasic acid component (c) that has a carboxyl equivalent ratio of 0.7 times or less to the total hydroxyl equivalent of the polyhydric alcohol component (a) until the acid value of the product becomes 30 or less. Obtained by reacting a condensation product (d) obtained by a condensation reaction with an unsaturated aliphatic dibasic acid (e) having a carboxyl group equivalent ratio of less than the hydroxyl equivalent of the condensation product (d). unsaturated alkyd (A), tris(2-hydroxyethyl)isocyanurate selected from the group consisting of diacrylate, triacrylate, dimethacrylate and trimethacrylate;
-Hydroxyethyl)isocyanurate-(meth)acrylate (B) and, if necessary, a polymerizable monomer (C) copolymerizable with the above-mentioned components (A) and (B).