JPS6255553B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing an insulated wire using a paint that uses an excellent low-pollution and low-toxicity solvent. Currently, it is used as an insulated wire for its electrical, mechanical,
Polyester wire is mainly used from the viewpoint of chemical performance and cost. Furthermore, as electrical equipment has recently become smaller, lighter, and more sophisticated, the performance requirements for insulated wires have also increased, and demand for highly heat-resistant polyester-imide wires or polyester amide-imide wires is also increasing. . Phenols such as cresol, phenol, and xylenol are used as main solvents in the insulating paints used for these insulated wires. However, these phenols have a strong pungent odor, and if they come into contact with the skin, there is a risk of causing irritation, so care must be taken when handling them. Phenols are also subject to OSHA (Occupational
The permissible concentration is specified as 5PPM by the Safety and Health Administration, and when manufacturing insulated wires, equipment such as local exhaust ventilation is required to prevent adverse effects on the working environment and human health. Furthermore, it has become necessary to prevent the phenols evaporated in the baking furnace from dispersing into the atmosphere.General baking furnaces are equipped with catalytic combustion equipment to treat the generated phenols, but these require large amounts of money. Equipment costs and maintenance costs are required. In order to deal with this situation, an insulating paint made by dissolving a polyester resin in a specific polyhydric alcohol derivative as shown below has been proposed. (Special Publication No. 53-34206, JP-A-50-150737,
Examples of specific polyhydric alcohol derivatives include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether,
Propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, Propylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, or lower alkyl esters thereof, such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, Ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene These include glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, dipropylene glycol monomethyl ether acetate, and the like. These polyhydric alcohol derivatives used in insulating paints that have been proposed in the past have less irritating odor than phenols, do not cause irritation when they come into contact with the skin, and are easy to handle. However, insulated wires manufactured by applying and baking paints according to these proposals have poor heat resistance, heat softening resistance, abrasion resistance, etc., compared to insulated wires obtained from paints containing phenols as the main solvent. Characteristics are inferior. The reason for this is that the polyhydric alcohol derivatives used as solvents for these paints have inferior dissolving power compared to phenols, and it is necessary to increase the solubility of the resin. This is because they are manufactured. The resins used in conventional phenolic paints have higher molecular weights than these proposed resins, so when they are dissolved in the proposed solvents, they hardly dissolve, making it difficult to separate the resin and solvent. occurs, making it impossible to use it as a paint. Therefore, we used a paint that uses a safer, less polluting, and less toxic solvent to improve the thermal stability, heat deterioration resistance, flexibility, and electrical insulation properties of conventional insulated wires.
The emergence of electric wires that do not impair thermal, mechanical, electrical, and chemical properties such as hydrolysis resistance and chemical resistance has been long awaited. After repeated studies to meet these demands, we found Gardner-Hold's m-cresol solution, which is obtained by reacting a polyhydric carboxylic acid or its derivative with a polyhydric alcohol and has a resin concentration of 40% by weight at 25°C. The present invention was completed based on the discovery that a resin having a viscosity of W or higher is soluble in a solvent containing a specific glycol monophenyl ether as a main component. Generally, by using the correlation between the molecular weight of a polymer material such as polyester resin and its solution viscosity,
The molecular weight of a resin is usually expressed by its solution viscosity. That is, a polymeric substance with a high solution viscosity has a higher average molecular weight than a polymeric substance with a lower solution viscosity. Therefore, in the present invention as well, the molecular weight of a resin obtained by reacting a polyhydric carboxylic acid or its derivative with a polyhydric alcohol was measured using a Gardner-Hold foam viscometer. The Gardner Holt foam viscometer measures the viscosity of liquids.
This is a viscometer that measures the rate of rise of bubbles, and compares the rate of rise of bubbles between a standard solution of known viscosity and a sample solution, and compares the viscosity of the standard solution and sample solution. Gardner-Holdt viscosity is expressed in terms of alpha and its viscosity value (25℃, Stokes)
Some of the relationships are shown below.

[Table] In the polyhydric alcohol derivative solvents that have been proposed in the past, the dissolving power rapidly decreases as the molecular weight of the polyester resin increases, and these solvents are unable to dissolve resins with a certain molecular weight or more. The solution exhibits very little or even if dissolved, the stability of the solution over time is very low. However, in the case of the glycol monophenyl ether solvent proposed in the present invention, the dissolving power is relatively poor for low molecular weight polyester resins that are soluble in the conventionally proposed polyhydric alcohol derivative solvents. Regardless, the molecular weight of the resin increases;
Conventionally proposed polyhydric alcohol derivative solvents have the ability to dissolve almost insoluble high molecular weight resins.
Very good. This fact is truly surprising and completely unexpected. According to the present invention, by using a solvent that has excellent dissolving power for high molecular weight resins, has no irritating odor, does not cause irritation even if it comes into contact with the skin, and is easy to handle. , it is possible to obtain a paint in which the resin used in conventional phenolic paints is dissolved without reducing its molecular weight. Therefore, compared to conventional insulated wires, it has better thermal stability, heat deterioration resistance, and flexibility. thermal, mechanical, electrical insulation, hydrolysis resistance, chemical resistance, etc.
It is possible to obtain an electric wire that does not deteriorate its electrical or chemical properties. The present invention uses a resin obtained by reacting a polyhydric carboxylic acid or its derivative with a polyhydric alcohol, and whose Gardner-Holdt viscosity of an m-cresol solution with a resin concentration of 40% by weight at 25°C is W or more. general formula

[Formula] [In the formula, m is an integer of 2 to 3 and n is an integer of 1 to 3. ] This invention relates to a method for manufacturing an insulated wire, which comprises applying and baking a paint dissolved in a solvent containing glycol monophenyl ether as a main component onto a conductor, either directly or through another insulator. In the present invention, when reacting a polyhydric carboxylic acid or its derivative with a polyhydric alcohol, the resin is sampled from time to time, and m-
A cresol solution is prepared and the Gardner-Holdt viscosity of this solution is measured. The point at which the Gardner-Holdt viscosity at 25° C. exceeds W, that is, the point at which the solution viscosity becomes higher than W, must be defined as the end point of the reaction. If the reaction is terminated at a viscosity lower than W, the heat resistance of the coating film will be insufficient, and from the viewpoint of storage stability of the coating material, a coating material lacking in stability will be obtained, which is not preferable. Further, from the viewpoint of the flexibility, abrasion resistance and heat resistance of the coating film, it is more preferable to set the reaction end point at the point at which Z ₃ or higher, that is, the point at which the solution viscosity becomes higher than Z ₃ . General formula used in the present invention

[Formula] [In the formula, m is an integer of 2 to 3 and n is an integer of 1 to 3. ] Examples of glycol monophenyl ethers include ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, triethylene glycol monophenyl ether, propylene glycol monophenyl ether, dipropylene glycol monophenyl ether, tripropylene glycol monophenyl ether, etc. can be given. These glycol monophenyl ethers can be used alone, or two or more types of glycol monophenyl ethers can be used in combination. Further, other solvents can be used within a range that does not impair the effects of the present invention. Other solvents used with glycol monophenyl ethers include xylene, naphtha, xylenol, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, cresol, or ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monoethyl ether, Examples include conventionally proposed polyhydric alcohol derivatives such as ethyl ether acetate. A polyhydric carboxylic acid or a derivative thereof and a polyhydric alcohol can be easily reacted by a conventional method, and there are no particular limitations on the reaction method. Examples of polyhydric carboxylic acids or their derivatives include isophthalic acid, terephthalic acid, orthophthalic acid, phenylindane dicarboxylic acid, benzophenonedicarboxylic acid, adipic acid, succinic acid, maleic acid, sebacic acid, isosebacic acid, and dimer acid. , tetrachlorophthalic acid, trimellitic acid, hemimellitic acid, trimesic acid, pyromellitic acid, benzophenonetetracarboxylic acid, general formula [wherein R is a divalent aliphatic, alicyclic, or aromatic hydrocarbon group having at least 2 carbon atoms,
or a combination of these groups, and further includes those having a side chain in the chain, for example, R is -(CH ₂ -) ₆

【formula】

【formula】

Examples include compounds having an imide ring in the molecule represented by the following formula, and derivatives such as anhydrides and esters of these acids. From the viewpoint of heat resistance of the coating film, terephthalic acid, isophthalic acid, and the following compounds having an imide ring in the molecule are more preferable. or its lower alkyl esters. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-
Butanediol, 1,4-butanediol, 1,
3-propanediol, 1,6-hexanediol, hydrogenated bisphenol A (hydrogenated 4,4'-dihydroxydiphenylpropane), 1,4-cyclohexane diethanol, 1,4-cyclohexanedimethanol, 1,4 -pentanediol,
Neopentyl glycol, trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, diglycerin, dipentaerythritol, tris(2-hydroxypropyl)
Examples include isocyanurate, tris(2-hydroxyethyl)isocyanurate, and the like. From the viewpoint of the flexibility and heat resistance of the coating film, ethylene glycol, glycerin, trimethylolpropane, and tris(2-hydroxyethyl) isocyanurate are more preferred. The paint obtained in this way can be used as is for insulated wires, but a hardening agent may be added to speed up the hardening during baking and to improve the physical and chemical properties of the paint film. preferable. Examples of curing agents include tetrabutyl titanate, tetraisopropyl titanate, and tetraphenyl titanate, which are commonly used in electrical insulation paints.
Organic titanium compounds such as dibutyl ditriethanolamine titanate, dibutyl diacetoacetic acid ethyl titanate, dibutyl diacetylacetone titanate, etc. can be used. In addition, blocking isocyanate compounds may be used in combination, and in addition, zinc naphthenate, cobalt naphthenate, zinc octenoate, manganese octenoate,
It is also effective to add metal salts of organic acids such as tin octenoate. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but these are merely examples, and the present invention is not limited to these Examples. In the following examples and reference examples, the reaction was carried out in a four-necked flask with a condenser, a thermometer, a nitrogen inlet tube,
The reaction was carried out with sufficient stirring in a reaction vessel equipped with a stirring device. Further, the viscosity was measured by preparing a m-cresol solution with a resin concentration of 40% by weight and using a Gardner-Hold foam viscometer at 25°C. In addition, when applying and baking paint onto copper wires, please be sure to
Using a 10m vertical furnace, the furnace temperature is 360℃ in the upper part and 320℃ in the middle.
It was baked on a copper wire with a diameter of 1.0 mmφ under conditions of 260°C and 260°C. Reference Example Dimethyl terephthalate 311 g (1.6 mol), ethylene glycol 74 g (1.2 mol), glycerin 74 g (0.8 mol), and lead acetate 0.64 g were reacted in 300 g of xylene. While gradually increasing the temperature from 140°C to 240°C, xylene and methanol, a byproduct of the reaction, were distilled out of the system through a cooler. Once it reaches 240℃, keep it warm at this temperature.
Sample the contents of the flask, measure the Gardner-Holdt viscosity, and stop heating when the viscosity reaches V.
I took out the resin. Furthermore, with similar raw materials and reactions, the Gardner-Holdt viscosities are W ~ X (between W and X), Z ₂ and
A resin with Z ₃ to _{Z 4} (between Z ₃ and Z ₄ ) was created. Table 1 shows the results of dissolving these four resins in the glycol monophenyl ether solvent used in the present invention shown below. For comparison, the results obtained by dissolving the polyhydric alcohol derivatives in conventionally proposed solvents are also shown. The glycol monophenyl ethers used in the present invention include: 1 DOWANOL EPh (manufactured by Dow Chemical Company, containing 92% or more ethylene glycol monophenyl ether) 2 DOWANOL PPh (manufactured by Dow Chemical Company, containing 92% or more propylene glycol monophenyl ether) It was used. As conventionally proposed polyhydric alcohol derivatives used for comparison, 3 ethylene glycol monoethyl ether 4 diethylene glycol monoethyl ether 5 diethylene glycol monopropyl ether 6 ethylene glycol monoethyl ether acetate was used.

[Table] As can be seen from this table, the dissolving power of the glycol monophenyl ether solvent proposed by the present invention for resins is superior to that of the polyhydric alcohol derivative solvents proposed in the past.
In particular, the dissolving power for resins with high molecular weights is extremely good. Comparative Example 1 Tetrabutyl titanate 2 was added to 100 parts by weight of the resin synthesized in Reference Example and having a Gardner-Holdt viscosity of V.
parts by weight and 2 parts by weight of zinc octate were added, and further dissolved with ethylene glycol monoethyl ether acetate so that the resin concentration was 52.6%.
The viscosity of this paint at 30℃ was determined using a B-type rotational viscometer.
It was hot at 12 poise. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. Example 1 The Gardner-Holdt viscosity synthesized in the reference example is W~
Adding 2 parts by weight of tetrabutyl titanate and 2 parts by weight of zinc octenoate to 100 parts by weight of resin X,
Furthermore, the resin concentration was increased to 54.4%.
Dissolved with DOWANOL EPh. The viscosity of this paint at 30°C was 30 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. Example 2 Tetrabutyl titanate 2 was added to 100 parts by weight of the resin synthesized in Reference Example and had a Gardner-Holdt viscosity of Z ₂ .
parts by weight, and 2 parts by weight of zinc octate were added to DOWANOL so that the resin concentration was 51.4%.
Dissolved with EPh. The viscosity of this paint at 30°C was 30 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. Example 3 The Gardner-Holdt viscosity synthesized in the reference example is Z ₃ ~
To 100 parts by weight of Z ₄ resin, 2 parts by weight of tetrabutyl titanate and 2 parts by weight of zinc octenoate were added to make the resin concentration 44.8%.
Dissolved with DOWANOL EPh. The viscosity of this paint at 30° C. was 57 poise using a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. Comparative Example 2 The Gardner-Holdt viscosity synthesized in the reference example is Z ₃ ~
To 100 parts by weight of Z ₄ resin, 2 parts by weight of tetrabutyl titanate and 2 parts by weight of zinc octenoate were added, and further dissolved with cresol so that the resin concentration was 40.2%. The viscosity of this paint at 30°C was 60 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulating paint obtained by applying and baking this paint onto a copper wire. Example 4 Dimethyl terephthalate 291 g (1.5 mol) Trimellitic anhydride 38 g (0.2 mol) 4,4'-diaminodiphenylmethane
22g (0.1 mol) ethylene glycol 74g (1.2 mol) glycerin 74g (0.8 mol) lead acetate 0.60g were reacted in 300g of xylene in the same manner as in the reference example.
When the Gardner-Holdt viscosity reached _Z5 , heating was stopped and the resin was taken out. To 100 parts by weight of this resin, 2 parts by weight of tetrabutyl titanate and 2 parts by weight of zinc octate were added to make the resin concentration 45.7%.
DOWANOL EPh and xylene 9:1 (weight ratio)
It was dissolved in a mixed solution of The viscosity of this paint at 30°C was 76 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. Example 5 Dimethyl terephthalate 272g (1.4mol) Trimellitic anhydride 77g (0.4mol) 4,4'-diaminodiphenylmethane
44 g (0.2 mol) ethylene glycol 74 g (1.2 mol) glycerin 74 g (0.8 mol) lead acetate 0.56 g were reacted in 250 g of xylene in the same manner as in the reference example.
When the Gardner-Holdt viscosity reached _Z4 to _Z5 , heating was stopped and the resin was taken out. To 100 parts by weight of this resin, 2 parts by weight of tetrabutyl titanate and 2 parts by weight of zinc octenoate were added to make the resin concentration 48.5%.
DOWANOL It was dissolved in a mixed solution of EPh and cresol at a ratio of 9:1 (weight ratio). The viscosity of this paint at 30°C was 85 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. Example 6 Dimethyl terephthalate 311g (1.6mol) Ethylene glycol 74g (1.2mol) Glycerin 60g (0.65mol) Tris(2-hydroxyethyl)isocyanurate 39g (0.15mol) Lead acetate 0.64g in xylene 300g Reference example React in the same way as
When the Gardner-Holdt viscosity reached _Z6 , heating was stopped and the resin was taken out. To 100 parts by weight of this resin, 2 parts by weight of tetrabutyl titanate and 2 parts by weight of zinc octoate were added to make the resin concentration 46.5%.
DOWANOL EPh and ethylene glycol monoethyl ether acetate were dissolved in a mixed solution of 9:1 (weight ratio). The viscosity of this paint at 30°C was 24 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. Example 7 Dimethyl terephthalate 311g (1.6mol) Ethylene glycol 74g (1.2mol) Glycerin 46g (0.5mol) Tris(2-hydroxyethyl)isocyanurate 78g (0.3mol) Lead acetate 0.64g in 300g of xylene as a reference example React in the same way as
When the Gardner-Holdt viscosity reached _Z7 , heating was stopped and the resin was taken out. To 100 parts by weight of this resin, 2 parts by weight of tetrabutyl titanate and 2 parts by weight of zinc octenoate were added to make the resin content 44.4%.
DOWANOL EPh and DOWANOL PPh 5:5
(weight ratio) of the mixed solution. The viscosity of this paint at 30°C was 28 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by coating and baking this paint onto the copper wire. In addition, as an example of a paint using conventionally proposed polyhydric alcohol derivatives as a solvent,
The coating material described in Example 5 of the above issue was synthesized as Comparative Example 3. Comparative Example 3 Dimethyl terephthalate 453 g, isophthalic acid 97 g, ethylene glycol 34 g, 1,6 hexanediol 86 g, glycerin 145 g, and tetrabutyl titanate 0.8 g were reacted while gradually increasing the temperature from 150°C to 225°C. When the temperature reached 225°C, sample the contents of the flask while keeping it at this temperature. When the Gardner-Holdt viscosity reached X, stop heating and cool it. Add 261 g of ethylene glycol monoethyl ether acetate and 65 g of xylene, 30 g of dibutyl diacetylacetone titanate and 0.65 g of zinc naphthenate were added. The resin concentration of the paint thus obtained was 61%, and the viscosity at 30°C was 52 poise as measured by a B-type rotational viscometer. Table 2 shows the properties of the insulated wire obtained by applying this paint to a copper wire and baking it.

[Table] As is clear from Table 2, the insulated wire of the present invention has much superior properties compared to the insulated wire obtained from the conventionally proposed paint using polyhydric alcohol derivatives as a solvent. Furthermore, it has properties equivalent to or better than insulated wires obtained from paints using phenolic solvents that are currently in use. As is clear from the above description, the insulated wire of the present invention does not cause any irritation even if it accidentally comes into contact with the skin, is made of a highly safe paint that uses a low-pollution, low-toxicity solvent, and Compared to conventional insulated wires, it has superior thermal, mechanical, electrical, and chemical properties such as thermal stability, heat deterioration resistance, flexibility, electrical insulation, hydrolysis resistance, and chemical resistance. Not damaged.

Claims (1)

[Claims] 1. A resin obtained by reacting a polyhydric carboxylic acid or its derivative with a polyhydric alcohol, in which the Gardner-Holdt viscosity of an m-cresol solution with a resin concentration of 40% by weight at 25°C is W or more. , the following general formula [Formula] [where m is an integer of 2 to 3 and n is an integer of 1 to 3]. ] A method for producing an insulated wire, comprising applying and baking a paint dissolved in a solvent containing glycol monophenyl ether as a main component onto a conductor, either directly or through another insulator. 2 Glycol monophenyl ether represented by the general formula [formula] is
The method for producing an insulated wire according to claim 1, wherein the insulated wire is ethylene glycol monophenyl ether or propylene glycol monophenyl ether. 3 Polycarboxylic acids or derivatives thereof include terephthalic acid, isophthalic acid, and compounds having an imide ring in the molecule shown below. Alternatively, the method for producing an insulated wire according to claim 1, which is a lower alkyl ester thereof. 4. The method for producing an insulated wire according to claim 1, wherein the polyhydric alcohol is ethylene glycol, glycerin, trimethylolpropane, or tris(2-hydroxyethyl) isocyanurate. 5. The method for manufacturing an insulated wire according to claim 1, wherein the Gardner-Holdt viscosity of the m-cresol solution with a resin concentration of 40% by weight at 25°C is _Z3 or higher. 6. Production of an insulated wire according to claim 5, wherein the polyhydric carboxylic acid is terephthalic acid, and the polyhydric alcohol is ethylene glycol, glycerin, and tris(2-hydroxyethyl) isocyanurate. Method.