JPH04202568A - Varnish for coil impregnation - Google Patents

Abstract

PURPOSE:To obtain the subject varnish useful for the purpose of insulation improvement, fixing, vibration damping, rust-proofing, etc., of a rotary machine, transformer, etc., by adding a specific resin component to a solvent composed of a hydrocarbon solvent and a solvent containing vinyl group. CONSTITUTION:The objective varnish is produced by adding a resin component composed mainly of (A) an alkyd resin containing unsaturated part in the molecular structure and (B) a coreactive resin (e.g. phenolic resin and melamine resin) to a solvent composed of (C) a hydrocarbon solvent (e.g. gasoline or naphtha) and (D) a solvent having vinyl group in the molecular structure (e.g. styrene or vinyltoluene).

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a coil-impregnated varnish used for the purposes of reinforcing insulation, fixing, anti-vibration, anti-corrosion, etc. for various types of rotating machines, transformers, and other equipment. It is.

[Conventional technology]

BACKGROUND ART Conventionally, motors and transformers of equipment such as rotating machines and transformers have been treated with coil-impregnated varnish for the purpose of reinforcing insulation, fixing, vibration proofing, rust prevention, etc. The above-mentioned coil impregnating varnishes are generally classified into two types, solvent-free type and solvent type, and are selected and used depending on the type of equipment, method of use, etc.

As the above-mentioned solvent-free coil impregnating varnish, for example, one in which a resin containing unsaturated polyester as a main component is dissolved with a reactive monomer such as a styrene monomer is used. In addition, the above-mentioned solvent-type coil-impregnated varnish is generally made of a compound consisting of an alkyd resin consisting of an unsaturated fatty acid, at least one of an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and a polyhydric alcohol, a phenolic resin, and a melamine resin. A resin, epoxy resin, or the like is added thereto, and this is dissolved in an organic solvent such as styrene or xylene. The above-mentioned solvent-free type and solvent-type coil impregnated varnishes are both used by causing an addition or condensation reaction by heating to crosslink and increase the molecular weight.

[Problem to be solved by the invention]

However, although the solvent-free coil impregnation varnish has a short curing and drying time, the pot life (pot life) of the varnish after the addition of a curing agent is short, and it is required to be handled carefully. Further, although the solvent-based coil-impregnated varnish has a long pot life, the varnish takes a long time to harden and dry and has a large volatile content, so the amount of film deposited in one application is small. Therefore, in order to obtain the required amount of adhesion, it is necessary to repeat the application many times.

As described above, conventional coil-impregnated varnishes have advantages and disadvantages in both solvent-free and solvent-type varnishes, and the reality is that no one has yet been obtained that combines the excellent properties of both types.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a high-concentration coil-impregnated varnish with a short curing and drying time, excellent coating workability, and low volatile content.

[Means for Solving the Problems] In order to achieve the above object, the coil impregnated varnish of the present invention contains fi10% consisting of the following (A) and (B):
It has a structure in which a resin component containing the following (C) and (D) as main components is contained.

(A) Hydrocarbon solvent.

(B) A solvent having a vinyl group in its molecular structure.

(C) Alkyd resin having an unsaturated portion in its molecular structure.

(D) Coreactive resin.

[Effect]

That is, the present inventors have conducted a series of studies in order to obtain a coil-impregnated varnish that has excellent application workability and has a low volatile content. As a result, the resin components of the solvent-based coil impregnated varnish include an alkyd resin that has an unsaturated portion in its molecular structure and a co-reacted resin, and the solvent is a conventionally used hydrocarbon solvent. , when combined with a solvent that has a vinyl group in its molecular structure, the viscosity is low,
The present invention was achieved by discovering that a product with a short curing and drying time and a low volatile content can be obtained.

Note that the above-mentioned main component is intended to include cases where the main component is comprised only.

The coil impregnating varnish of this invention uses a mixed solvent consisting of a hydrocarbon solvent (component A) and a special solvent (component B).
It contains a resin component whose main components are a special alkyd resin (component C) and a coreactive resin (component D).

The hydrocarbon solvent (component A) is not particularly limited, and conventionally used gasoline solvents may be used, such as gasoline, naphtha, and the like.

The above-mentioned special solvent (component B) is a solvent that has a vinyl group in its molecular structure, and this vinyl group and the unsaturated moiety in the alkyd resin (component C) described later react with each other by heating, and the reaction causes The base resin concentration increases. Therefore, the amount of film deposited on the object to be coated increases. Examples of the solvent having a vinyl group in its molecular structure include methacrylic ester compounds, acrylic ester compounds, and styrene. Specific examples include styrene, vinyltoluene, divinylbenzene, and α-methylstyrene. In addition, those represented by the following general formula are also used.

H,C=CHCOO-R-00CHC-CH.

HyoC=C(CHs)Coo-R-00C(CHs
) C-CHlH, C-CHCoo-R' H, C-C(CH3)Coo-R' These are used alone or in combination.

The above-mentioned special solvent (B component) is the above-mentioned hydrocarbon solvent (A
Ingredients) Medium 5-60! It is preferable to blend the above special solvent (hereinafter referred to as "%") within the range of
If the blending amount of component B) is less than 5%, a highly concentrated varnish cannot be obtained. This is because there is a tendency for flexibility to be lost.

The above-mentioned special alkyd resin (component C) has an unsaturated portion in its molecular structure. Such an alkyd resin (component C) contains unsaturated fatty acids and a small amount of aromatic dicarboxylic acid and aliphatic dicarboxylic acid (on the other hand,
It can be obtained using a polyhydric alcohol.

The unsaturated fatty acids mentioned above include linseed oil fatty acids.

Examples include tall oil fatty acid, castor oil fatty acid, tung oil fatty acid, soybean oil fatty acid, etc., which may be used alone or in combination.

Examples of the aromatic dicarboxylic acids and aliphatic dicarboxylic acids include phthalic anhydride, isophthalic acid, terephthalic acid, and tetrahydrophthalic anhydride.

Examples include succinic anhydride, adipic acid, maleic anhydride, fumaric acid, trimellitic anhydride, bis[(4-carboxy)phthalimide)4,4'-diphenylmethane, and the like. These may be used alone or in combination.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, neopentyl glycol, glycerin, tris-2-human-roxyisocyanurate pentaerythritol, and the like, which may be used alone or in combination.

The above-mentioned special alkyd resin (component C) is produced, for example, by blending the above-mentioned components and heating them to cause a reaction.

In the production of the alkyd resin (component C), the blending ratio of each of the above components, that is, unsaturated fatty acid (X), aromatic dicarboxylic acid and aliphatic dicarboxylic acid (Y), and polyhydric alcohol (Z) It is preferable to set the equivalent ratio of x+y to 1 and Z to 1.1 to 1.5.

Examples of co-reactive resins (component D) used together with the special alkyd resin (component C) include phenol resins, melamine resins, urethane resins, and epoxy resins, which may be used alone or in combination.

The amount of the co-reactive resin (component D) is preferably set at a ratio of 20 to 50% relative to the alkyd resin (component C).

Moreover, in addition to the above-mentioned components A to D, the coil-impregnated varnish of the present invention may contain a metal compound as a catalyst (curing aid) for the purpose of increasing the curability of the varnish. Examples of the metal compounds include tetrabutoxytitanium, cobalt naphthenate, and tin chloride. These may be used alone or in combination. The content of this metal compound is preferably set in the range of 0.1 to 0.7% in the entire coil impregnating varnish.

The coil-impregnated varnish of the present invention can be produced, for example, using the above-mentioned components in the following manner. That is, the special alkyd resin (C
component), a hydrocarbon solvent (component A), and a coreactive resin (D
component), a special solvent (component B), and a metal compound as appropriate. By going through such a series of steps, it is possible to produce the desired coil-impregnated varnish with low viscosity and low volatile content.

In addition, in the above method for producing coil impregnated varnish, as a condition for blending the special solvent (component B), it is preferable to blend the special solvent (component B) when the temperature of the compounded material (alkyd resin in the case of the above production method) is below 150 ° C. i.e. 150”C
This is because in the above cases, the unsaturated groups of the special solvent may undergo thermal polymerization, and as a result, the resulting varnish tends to gel.

The coil-impregnated varnish obtained in this way has good application workability, which is a characteristic of commonly used solvent-based varnishes, and has a low viscosity, overcoming the drawback of conventional solvent-based varnishes such as high volatile content. This is a varnish with a significantly higher concentration (more than 55%) than conventional varnish (about 30 to 55%) (low volatile content).

The coil impregnating varnish of the present invention can be impregnated and cured into a wound wire/molded coil by the same means as conventional solvent-type coil impregnating varnishes. Alternatively, it can be used containing a peroxide that acts as a hardening agent, and the curing time can be reduced compared to conventional solvent-based coil impregnated varnishes.

〔Effect of the invention〕

As described above, the coil-impregnated varnish of the present invention has an alkyd resin (component C) having an unsaturated portion in its molecular structure.
Since it contains a solvent (component B) that has a vinyl group in its molecular structure that reacts with the unsaturated moieties mentioned above, it has the excellent characteristics of both solvent-free and solvent-type products, and has a low viscosity. However, it has a high concentration, low volatile content, and excellent curability. Therefore, it has good workability and also has excellent film adhesion. Therefore, it has the excellent properties of a solvent-based coating and can form the required film with less application frequency.

Next, examples will be described together with comparative examples.

[Example 1] 160 g of linseed oil fatty acid and 68 g of glycerin were placed in a 1 liter four-loaf flask equipped with a stirring device, a temperature needle, a cooling tube with a trap, and a nitrogen gas-filled tube.

95g of isophthalic acid was added, stirred and heated, and when the temperature inside the system reached 150°C, distillation of reaction water was observed, and 2
32g when gradually heated to 10°C over 18 hours
The formation of distillate due to a reaction with water as the main component was observed. Then, after reducing the pressure to 10 mmHg for 30 minutes, the inside of the system was cooled to 170°C, 178 g of xylene, 125 g of phenol resin, and 0.4 g of stannous chloride were added.
When the temperature was raised to 0°C, the formation of distillate due to reaction was observed. This solution was cooled to 150 °C and xylene 44
g and 2 g of tetrabutoxytitanium as an additive,
4 g of 6% cobalt naphthenate solution was added, and 56 g of styrene was further added to obtain the desired coil-impregnated varnish.

[Example 2] Tris-2-hydroxyethyl isocyanurate was added to a 1 liter four-bottle flask equipped with the same equipment as in Example 1.
), 3 g of linseed oil JIM fatty acid 1e, and 72 g of isophthalic acid were added, and the temperature was gradually raised to 180°C for 2 hours and then to 210°C over 3 hours. Then, the reaction was continued for 8 hours in that state to produce an alkyd resin. When the acid value of the alkyd resin became 10 or less, the pressure was reduced to 10smHg for 30 minutes, and the system was cooled to 140°C. This was diluted with 155g of xylene, and then 200g of styrene and 90g of phenol resin were added.
The desired coil-impregnated varnish was obtained by adding 2 g at 40°C.

[Examples 3 to 8] The components shown in Table 1 below were blended in the proportions shown in the same table, and the intended coil-impregnated varnish was obtained in the same manner as in Example 1. In Table 1 below, the phenol resin is PP-8000 manufactured by Gunei Chemical Co., Ltd., the epoxy resin is Epicoat-1004 manufactured by Yuka Shell Co., Ltd., and the melamine resin is Super Beckamine J-820 manufactured by Dainippon Ink Company. was used.

(Left below) [Comparative Example 1] 160 g of linseed oil fatty acid and 68 g of glycerin were placed in a 1 liter four-bottle flask equipped with a stirrer, a temperature needle, a cooling tube with a trap, and a nitrogen gas-filled tube.

95 g of isophthalic acid was added, stirred, and heating started. When the temperature inside the system reached 150°C, distillation of reaction water was observed, and 2
When the temperature is gradually raised to 10°C over 18 hours, 31
The formation of a distillate due to a reaction containing water as the main component was observed. Then, after reducing the pressure to 10+++ mHg for 30 minutes, the inside of the system was cooled to 170°C, and 178 g+ of xylene was added.
125 g of phenolic resin.

When 0.4 g of stannous chloride was added and the temperature was raised again to 180°C, the formation of a distillate due to reaction was observed.

The solution was cooled to 150 °C, 100 g of xylene was added, and as additives 2 g of tetrabutoxytitanium, 6%
4 g of cobalt naphthenate solution was added to obtain a solvent-type coil impregnated varnish.

[Comparative Example 2] In a 1 liter four-bottle flask equipped with the same equipment as in Comparative Example 1, 150 g of tris-2-hydroxyethyl isocyanate, 163 g of linseed oil fatty acid, and 7 g of isophthalic acid were added.
2 g was added, and the temperature was raised to 180°C over 2 hours and then to 210°C over 3 hours, and the reaction was continued for 8 hours.

10m when the acid value of the generated resin becomes 10 or less
After reducing the pressure with aHg for 30 minutes, the system was cooled to 140°C, diluted with 355g of xylene, and phenolic resin 92.
g was added at 40°C to obtain a solvent-based coil impregnated varnish.

The viscosity and nonvolatile content of the actual height measurements and comparative example products obtained as described above were measured. The results are shown in Table 2 below.The non-volatile content measurement conditions were 150°C
It was time.

(Margin below) Furthermore, using the above-mentioned height measurement and comparative example product, apply it to a 180 am x 100 mm x 0.3-thick iron plate,
Measure properties such as volume resistivity, dielectric breakdown voltage, and flexibility.
The evaluation results are shown in Table 3 below along with the film thickness. In addition, as an evaluation of flexibility, those that are particularly excellent are ◎
, those that were excellent were indicated as O, and those that were poor were indicated as ×.

In addition, under the curing conditions in Table 3, *1 is applied once and cured at 135°C for 2 hours, and *2 is applied once and cured at 150°C.
Cure in 2 hours at °C, *3: 135 °C after one application
After curing for 1 hour, apply one more time at 135°C
hardened over time. *4 indicates the condition that after one coat was cured at 150°C for 1 hour, it was coated one more time and cured at 150°C for 2 hours.

(Left below) From the results in Tables 2 and 3, the measured heights are those with low viscosity and high non-volatile content. Therefore, the amount of varnish applied to the iron plate is larger than that in comparative height measurement, and when obtaining the same film thickness, it can be obtained with fewer applications. Furthermore, it can be seen that the film properties are comparable and better than conventional solvent-type coil impregnated varnishes.

Patent applicant: Nitto Denko Corporation Agent: Patent Attorney Yukihiko Nishifuji

Claims (1)

[Claims] (1) A coil-impregnated varnish characterized in that a resin component containing the following (C) and (D) as main components is contained in a solvent consisting of the following (A) and (B). (A) Hydrocarbon solvent. (B) A solvent having a vinyl group in its molecular structure. (C) Alkyd resin having an unsaturated portion in its molecular structure. (D) Coreactive resin.