KR100918097B1 - Water-soluble polyester varnish for electric insulating of electric wire - Google Patents

Abstract

The present invention relates to a varnish for insulation of electric wires, which is water-soluble and environmentally friendly in coating on copper wire wires for wires, wherein the polyhydric alcohol: polybasic acid has an equivalent ratio of 1.3 to 2: 1, and has a number average molecular weight of 2,000 to 7,000. It characterized in that it comprises within the range of 30 to 70% by weight relative to the total weight of the varnish.

Varnish, enamel, copper wire, coating, water soluble, eco-friendly, equivalence ratio, number average molecular weight

Description

Water-soluble polyester varnish for electric insulating of electric wire}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to insulating varnishes for electric wires that can be used to coat copper wire wires, and more particularly, to water-soluble polyester varnishes for insulating electric wires which are environmentally friendly as water-soluble in coating copper wire wires for electric wires.

Varnish is a generic name for paints made by dissolving a resin in a solvent and containing no pigment. Therefore, the coating film is usually formed transparent.

Copper wire wire is a kind of metal wire for transmitting electricity and refers to copper wire (copper wire) with excellent electrical conductivity and low power loss.

Copper wire, which is usually used as an electric cable, is covered with an insulator to achieve electrical insulation. Wires for delivering high voltage power have synthetic wires (shells of wires), but fine copper wires used in motors, etc. Cover the varnish for insulation to achieve electrical insulation.

However, the conventional enamel varnish contains cresols, phenols, aromatic organic solvents, and is toxic, and thus has a disadvantage of adversely affecting people and nature when preparing enamels or coating enamels. In particular, polyester copper enamel (abbreviated PE copper enamel) is mainly a solvent type copper enamel, and has been used by dissolving a polymer in cresol, phenol, and an aromatic solvent. However, polyester has a disadvantage that it is not environmentally friendly because it is insoluble in water.

The present invention has been made in order to solve the problems of the prior art as described above is to provide a water-soluble polyester varnish for the insulation of electric wires, which is water-soluble in coating the copper wire for the wire.

As described above, the insulation varnish of the electric wire for achieving the object of the present invention is a polyester resin having a polyhydric alcohol: polybasic acid equivalent ratio of 1.3 to 2: 1 and a number average molecular weight of 2,000 to 7,000 based on the total weight of the varnish. Characterized by including within the range of the amount of 30 to 70% by weight.

The polybasic acid constituting the polyester resin may allow 5 to 50% by weight of the polybasic acid to be dimethylterephthalate (DMT) based on the total weight of the polybasic acid.

The polyhydric alcohol constituting the polyester resin is a polyhydric alcohol of 2 to 8% by weight relative to the total weight of the polyhydric alcohol so that tris-2- (hydroxyhydroxy) isocyanurate (THIC) can do.

The polyester resin may be neutralized with an amine so that its pH is within the range of 7.5 to 8.5.

The amine is alkylamine, alkanolamine, morpholineamine, triethylamine, trimethylamine, triethanolamine, dimethylethanolamine, dibutylethanolamine, methylmorpholine, 2-amino-2-methyl-1-propanol or these It may be selected from the group consisting of two or more mixtures.

The insulating varnish of the wire may further comprise titanium chelate in an amount of 0.5 to 3% by weight based on the total weight of the insulating varnish.

The titanium chelate may be titanium chelate of acetylacetone or titanium chelate of triethanolamine or a mixture thereof.

The insulation varnish of the electric wire is a common one selected from the group consisting of butyrolactone, dimethyl sulfoxide, diacetone alcohol, dioxane methoxyethanol, isopropyl alcohol, diethylene glycol, butoxyethyl acetate or a mixture of two or more thereof. The medium may further comprise an amount of 10 to 30% by weight based on the total weight of the insulating varnish.

Therefore, according to the present invention, there is an effect of providing a water-soluble water-soluble polyester varnish for the insulation of the electric wire by using a water-soluble polyester resin in coating on the copper wire for the wire.

Hereinafter, the present invention will be described in detail with reference to specific examples.

The water-soluble polyester varnish for insulation of electric wires according to the present invention has a polyester resin having a polyhydric alcohol: polybasic acid equivalent ratio of 1.3 to 2: 1 and a number average molecular weight of 2,000 to 7,000 based on the total weight of the varnish. It is characterized by being made within the range of the amount of. The polyester resin is particularly excellent in solubility in water by setting the ratio of 1.3 to 2.0: 1 in the equivalence ratio of polyhydric alcohol and polybasic acid, and making the number average molecular weight within the range of 2,000 to 7,000, In addition, there is a feature in that the film properties and workability are improved. This is because the equivalent ratio of polyalcohol: polybasic acid of the conventional organic solvent type polyester resin is 1.1 to 1.3: 1 so that the solubility in water is not good, the organic solvent must be used inevitably. The water-soluble polyester varnish for insulation of electric wires according to the present invention can be coated on copper wire very easily, and the enamel wire made after coating has very excellent electrical properties. When the equivalent ratio of the polyhydric alcohol and the polybasic acid is less than 1.3: 1, there may be a problem that the hydrophilicity is lowered and the water solubility is lowered, and when the ratio exceeds 2.0: 1, a considerable amount of unreacted material may remain. In addition, when the number average molecular weight of the polyester resin is less than 2,000, there may be a problem that the film thickness variation in the enamel line is severe, if the excess exceeds 7,000, there may be a problem that the appearance is not smooth. The reaction for synthesizing the polyester resin is carried out at a temperature of 200 to 250 ℃ in a flask filled with all monomers. If the temperature is less than 200 ℃, there may be a problem that the molecular weight of the polyester resin obtained is too small, on the contrary, if it exceeds 250 ℃, the gelation phenomenon during the polymerization of the obtained polyester resin may appear. . It will be apparent to those skilled in the art that the reaction may be performed in a state in which some organic solvent is filled or in a state in which organic solvent is not filled.

As the polybasic acid, terephthalic acid (TPA) as the dicarboxylic organic acid, trimellitic anhydride (TMA) as the organic acid anhydride, dimethylterephthalate (DMT) or a mixture of two or more thereof may be used. As the polyhydric alcohol (polyol), one selected from the group consisting of ethylene glycol (EG), tris-2-hydroxyethyl isocyanurate, glycerin, neopentyl glycol (NPG) or a mixture of two or more thereof can be used. In particular, the dimethyl terephthalate as a polybasic acid improves the thermal shock resistance, the tris-2-hydroxyethyl isocyanurate as a polyhydric alcohol not only improves the thermal properties of the varnish but also improves the solubility in water.

The polybasic acid constituting the polyester resin may be 5 to 50% by weight of the polybasic acid to dimethylterephthalate (DMT) based on the total weight of the polybasic acid. This is because the conventional solvent-type polyester enamel tends to have poor thermal shock resistance due to its polymer structure, but in the present invention, dimethyl terephthalate is used in an amount of 5 to 50 compared to the solid content of the monomer in order to have excellent properties even at 175 ° C or higher. It was used in an amount of% by weight. If the dimethyl terephthalate is less than 5% by weight, there may be a problem that the thermal shock resistance is insufficient, on the contrary, if it exceeds 50% by weight, there may be a problem that the softening resistance worsens.

In addition, the polyhydric alcohol constituting the polyester resin has a polyhydric alcohol of 2 to 8% by weight based on the total weight of the polyhydric alcohol is tris- (2-hydroxyethyl) isocyanurate (THIC) You can do that. This is because the conventional solvent-type polyester enamel tends to have a poor heat index in terms of its polymer structure, but in the present invention, in order to have a good heat index, the tris-2-hydroxyethyl isocyanurate is used as the solid content of the monomer. The amount was used in an amount of 2 to 8% by weight. If the tris-2-hydroxyethyl isocyanurate is less than 2% by weight, there may be a problem that the heat index is insufficient, on the contrary, if it exceeds 8% by weight, there may be a problem that the thermal shock resistance is worse .

The polyester resin may be neutralized with an amine so that its pH is within the range of 7.5 to 8.5. Neutralization with the amine increases the solubility in water by forming a salt by reacting with the polybasic acid remaining unreacted in the polyester resin. The amine is alkylamine, alkanolamine, morpholineamine, triethylamine, trimethylamine, triethanolamine, dimethylethanolamine, dibutylethanolamine, methylmorpholine, 2-amino-2-methyl-1-propanol or these It may be selected from the group consisting of two or more mixtures. The amine is used to solubilize the polyester resin, and the amine reacts with an independent organic acid in an unreacted state to form a salt, and the salt has an affinity with water to improve the property of dissolving the polyester resin in water. It will function. The amine is used to adjust the hydrogen ion concentration (PH), and the pH is within the range of 7.5 to 8.5. If the pH is less than 7.5 or more than 8.5, there may be a problem that the enamel varnish does not maintain stability.

The water-soluble polyester varnish for insulation of the wire may further comprise titanium chelate in an amount of 0.5 to 3% by weight based on the total weight of the insulation varnish.

The titanium chelate may be titanium chelate of acetylacetone or titanium chelate of triethanolamine or a mixture thereof. The titanium chelate is used to increase the stability of the varnish. If the titanium chelate is used in less than 0.5% by weight or more than 3.0% by weight, there may be a problem that the storage stability of the varnish worsens.

The water-soluble polyester varnish for insulation of the electric wire is selected from the group consisting of butyrolactone, dimethyl sulfoxide, diacetone alcohol, dioxane methoxyethanol, isopropyl alcohol, diethylene glycol, butoxyethyl acetate or a mixture of two or more thereof. The selected cosolvent may be further included in an amount of 10 to 30% by weight based on the total weight of the insulating varnish. The cosolvent serves to aid in the solubilization of the polyester resin, and serves to improve the physical properties of the coating when the enamel is coated. When the cosolvent is used in an amount of less than 10% by weight, there may be a problem that the storage stability worsens, and when the cosolvent is more than 30% by weight, there may be a problem that an excessive amount of organic gas occurs.

It will be apparent to those skilled in the art that the water-soluble polyester varnish for insulation of electric wires according to the present invention as described above can be coated on copper wires or the like by using a facility for coating an existing organic solvent-type enamel varnish.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described.

The following examples are intended to illustrate the invention and should not be understood as limiting the scope of the invention.

Example  One

In a three-neck synthetic flask equipped with a gas injection device, a stirrer, a thermometer and a condenser, 61 g of ethylene glycol, 221 g of tris-2-hydroxyethyl isocyanurate, 24 g of glycerin, 34 g of dimethyl terephthalate, 119 g of terephthalic acid, and N-methylpi as a solvent 61g weight of N-methylpyrrolidone (NMP) and 61g weight of trimellitic anhydride were added, and it heated up gradually to 230 degreeC. The reaction is maintained at 230 ° C. to 240 ° C. for about 6 to 8 hours, and when the resin becomes transparent, the viscosity is measured using an ICI viscometer to stop the reaction if it is 10 to 20 Poise, and 159 g of butyl cellosolve is added thereto. After the addition and lowering to 100 ° C, 36 g of dimethylethanolamine was added thereto. 246 g of distilled water was added at 100 degrees C or less, and 11 g of titanium chelates of triethanolamine were added at 50 degrees C or less, and it stirred sufficiently. The reaction was terminated at a pH of 7.5 to 8.5 and a nonvolatile content of 50% to obtain a water-soluble polyester varnish for insulation of electric wires according to the present invention.

Example  2

In the same device as in Example 1, 69 g of ethylene glycol, 21 g of tris-2-hydroxyethyl isocyanurate, 80 g of glycerin, 30 g of dimethyl terephthalate, 195 g of terephthalic acid, 45 g of butyl cellosolve, and 45 g of trimellitic anhydride were added thereto. Then, it heated up gradually to 230 degreeC. The reaction is maintained at 230 to 240 ° C. for about 6 to 8 hours, and when the resin becomes transparent, the viscosity is measured by an ICI viscometer and the reaction is stopped if it is 10 to 20 poise, and 150 g of butyl cellosolve is added thereto. After the temperature was lowered to 占 폚, 25 g of dimethylethanolamine and 214 g of distilled water were added thereto. And 10 g of titanium chelates of triethanolamine were added at 50 degrees C or less, and it fully stirred. The reaction was terminated at a pH of 7.5 to 8.5 and a nonvolatile content of 50% to obtain a water-soluble polyester varnish for insulation of electric wires according to the present invention.

Example  3

Ethylene glycol 67 g, tris-2-hydroxyethyl isocyanurate 35 g, glycerin 82 g, neopentyl glycol 60 g, dimethyl terephthalate 34 g, terephthalic acid 188 g, butyl cellosolve 38 g, trimelli in the same device as in Example 1 After adding 64 g of tick anhydrides, it heated up gradually to 230 degreeC. The reaction was maintained at 230 to 240 ° C. for about 6 to 8 hours, and when the resin became transparent, the reaction was stopped at 30 to 40 poise by measuring the viscosity with an ICI viscometer. 146 g of butyl cellosolve was added thereto, and the temperature was lowered to 100 ° C., followed by 35 g of dimethylethanolamine and 173 g of distilled water. And 14g of titanium chelates of triethanolamine were added at 50 degrees C or less, and it fully stirred.

The reaction was terminated at a pH of 7.5 to 8.5 and a nonvolatile content of 50% to obtain a water-soluble polyester varnish for insulation of electric wires according to the present invention.

Comparative example

Ethylene glycol 79g, tris-2-hydroxyethyl isocyanurate 32g, glycerin 73g, trimethylolpropane (TMP, polyhydric alcohol) 34g, terephthalic acid 195g, NMP 46g, trimelli in the same device as in Example 1 After 45 g of tick anhydrides were added, the temperature was gradually raised to 230 ° C. The reaction was maintained at 230 to 240 ° C. for about 6 to 8 hours, and when the resin became transparent, the viscosity was measured using an ICI viscometer to stop the reaction if it was 10 to 20 poise. After 198 g of butyl cellosolve was added thereto and the temperature was lowered to 100 ° C., 25 g of triethylamine and 214 g of distilled water were added as a neutralizing agent. And 14 g of tetraisopropyl titanate was put at 50 degrees C or less, and it fully stirred. The reaction was terminated at a pH of 7.5 to 8.5 and a 50% nonvolatile content to obtain a conventional enamel varnish as a control.

Experimental Example

The copper wire coating using the varnish of the examples and the comparative example used a copper enamel coating oven widely used. The length was about 3.4 m and the temperature in the oven was maintained at inlet / outlet = 460 ° C / 540 ° C. The thickness of the wire was 0.5 mm (φ) of copper wire, and the coating speed was maintained at 26 m / min. The number of coatings was carried out seven passes.

After coating, the properties of the obtained copper wire were tested and the results are shown in Table 1 below.

  Test Items   Test Methods   standard  The present invention    Comparative example  Example 1  Example 2  Example 3  Exterior  Visually  Flawless and Clean  Inadequate  Good  Good  Inadequate  Film thickness / outer diameter (mm)  Measured with a micrometer  0.017 or more / 0.560 or less  0.025 / 0.550  0.025 / 0.550  0.025 / 0.550  0.025 / 0.550  Eccentricity (mm)  Outer car  10 / 1,000 or less  15 / 1,000  7 / 1,000  4 / 1,000  13 / 1,000  Pinhole count (water impregnation)  5 m, 12 V, 1 minute  3 or less  5  0  0  8  Breakdown voltage (㎸)  Double twisted twist 450g, 12times  3.05 or more  7  7  7.5  5  Softening resistance (℃)  Temperature Crossing Load 500g  More than 240  325  314  325  290   Abrasion Resistance (g)   One-way  Minimum 445 or above / Average 552 or above   800 / 1,150   850 / 1,200   900 / 1,200   700 / 1,050  Thermal shock resistance  3 times of winding, 20 times of 175 degrees Celsius * 1hr  No cracks   3 cracks   1 crack   0 cracks   4 cracks

As a result of the synthesis of the above embodiments, the varnish according to the present invention is similar to the comparative example for some properties, but has the advantage of providing excellent physical properties for some properties and at the same time water-soluble and environmentally friendly.

The present invention can be used for various purposes, including the manufacture of components in the electric industry, such as the production of copper wire.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (5)

Polyhydric alcohol: polybasic acid equivalent ratio of 1.3 to 2: 1, the number average molecular weight of 2,000 to 7,000, including a polyester resin within the range of 30 to 70% by weight based on the total weight of the varnish, the total weight of the polybasic acid A water-soluble polyester varnish for insulation of electric wires, wherein 5 to 50% by weight of the polybasic acid is dimethyl terephthalate. delete The method of claim 1, The polyhydric alcohol constituting the polyester resin is a water-soluble polyester varnish for insulation of electric wire, characterized in that 2 to 8% by weight of the polyhydric alcohol is tris-2-hydroxyethyl isocyanurate relative to the total weight of the polyhydric alcohol. The method of claim 1, A water-soluble polyester varnish for insulation of electric wires, characterized in that dimethylethanolamine is used as a neutralizing agent to aid in the solubilization of the polyester resin. The method of claim 1, Water-soluble polyester varnish for insulation of the electric wire, characterized in that further comprises a titanium chelate of triethanolamine in an amount of 0.5 to 3.0% by weight based on the total weight of the insulating varnish for the storage stability of the polyester resin.