KR101308732B1 - Tension coating agent for forming insulating film with excellent glossy property, electrical resistance and method for forming insulation film using that, and oriented ecectrical steel sheet with coated insulating film that method - Google Patents

Abstract

The present invention relates to a tension coating composition for a grain-oriented electrical steel sheet having excellent gloss and insulation, a method of forming an insulating film using the same, and a grain-oriented electrical steel sheet having an insulating film formed by the method. In the insulating film treatment process of a grain-oriented electrical steel sheet, metal phosphate and colloidal Tension coating agent of a grain-oriented electrical steel sheet mainly composed of silica, the metal phosphate is a mixed solution of the first magnesium phosphate (Mg (H ₂ PO ₄ ) ₂ ) and the first aluminum phosphate (Al (H ₂ PO ₄ ) ₃ ) ego; With respect to the metal phosphate solution 100g, it provides a tension coating composition for a grain-oriented electrical steel sheet excellent in gloss and insulation, characterized in that it comprises a colloidal silica solid content of 30 ~ 60g having a particle size of 5 ~ 15nm.
According to the present invention, by improving the drying rate of the coating agent by varying the composition ratio of the metal phosphate, which is the main component of the oriented electrical steel sheet tension coating agent, it is possible to solve the problem of poor insulation due to undrying, and to remove the particles of colloidal silica By lowering the coating roughness in combination with a fine size of 30% or more, the effect of ultimately improving the electrical insulation and the gloss of the film can be obtained.

Description

Tension coating composition for oriented electrical steel with excellent gloss and insulation, and method for forming insulating film using same, oriented electrical steel sheet having insulating film formed by the method INSULATION FILM USING THAT, AND ORIENTED ECECTRICAL STEEL SHEET WITH COATED INSULATING FILM THAT METHOD}

The present invention relates to a tension coating composition for oriented electrical steel having excellent gloss and insulation, and to a method of forming an insulating coating using the same, and to a oriented electrical steel sheet having an insulating coating formed by the method, in particular, to prevent the reduction of eddy current loss due to the electrical insulating inferiority of the coating and Tension coating composition for oriented electrical steel with excellent gloss and insulation to improve the efficiency of the transformer due to high insulation between layers and ultimately to improve the feeding performance in the lamination work for transformer manufacturing by improving the efficiency and forming an insulating film using the same A method and a grain-oriented electrical steel sheet having an insulating coating formed by the method.

As is well known, a grain-oriented electrical steel sheet is a steel sheet containing 3.1% Si, which has an aggregate structure in which the grain orientation is aligned in the (110) [001] direction, and the product has extremely excellent magnetic properties in the rolling direction. It is used for iron core materials such as transformers, motors, generators, and other electronic devices.

The process related to the present invention is a final process of insulating electrical coating and flattening annealing of a grain-oriented electrical steel sheet, this process is subjected to the annealing process after the recoating on the primary coating consisting of a layer of oriented electrical steel sheet forsterite This means that the magnetic properties of the material can be improved by the tensile stress added by the thermal expansion coefficient difference between the film and the material in the cooling process after annealing.

Excellent insulation coating should basically have a uniform color without defects in appearance, but the technique was mainly used to improve the electrical insulation and enhance the adhesion of the film by incorporating various techniques to give functionality.

Recently, the commercialized high-strength oriented electrical steel sheet has been commercialized, and it has been found that the high tensile tension of the final insulating film has been pursued, and the actual high tensile insulating film has contributed significantly to improving the magnetic properties of the final product.

In addition, the control technique of various process factors is applied to improve the characteristics of the tension film, and currently commercialized oriented electrical steel sheet by using the difference in the coefficient of thermal expansion of the insulating film formed on the steel sheet and the base layer of the fosterite-based film A good example is the reduction of the iron loss effect by adding tensile stress.

As a typical method of forming an insulating film, a method of improving the film tension by using colloidal silica having a high temperature glass transition point as in Japanese Patent Laid-Open No. 11-71683 or in Japanese Patent No. 3098691 and Japanese Patent No. 2688147 Similarly, a technique for forming a high tensile oxide film on an electrical steel sheet using an alumina sol of alumina main body and a mixture of boric acid is disclosed.

In addition, by forming a first layer composed of hydrogen phosphate salt and silica containing a specific metal atom on the porsterite base coating as in Korea Patent No. 0377566, it is possible to improve the adhesion between the base layer and the insulating coating A technique of inducing and forming a second layer containing aluminum borate as a main component thereon to produce a stronger film tension effect is disclosed.

In recent years, the high magnetic flux density-oriented oriented electrical steel sheet has been commercialized, and the high tensile strength of the final insulating film has been pursued. Accordingly, a new function of magnetic improvement has been added.

The tension imparting ability of the conventional insulating film is 0.30 to 0.36 kg / mm2 for 0.23mm oriented electrical steel sheet, and the magnetic contribution to the final product is improved by about 2 ~ 3% even with this tension. Is being reported.

Therefore, the improvement of magnetism by applying the high tension of the coating layer affects the iron core loss, that is, the iron loss in the magnet, and can improve the magnetization because the eddy current loss can be reduced by the tension applied to the material.

In addition, in order to reduce the eddy current loss of the electrical steel sheet is made of a thin plate material, when the laminated material is used if the surface of the plate is not insulated, the lamination effect by the thin plate disappears. Therefore, the surface insulation is very important in the electrical steel sheet, for this purpose, the role of the tension coating for providing electrical insulation to the steel sheet is very large.

In particular, electrical insulation is more important in high voltage transformers. As mentioned above, most of the current tension coating research is focused on the development of Cr-free coatings that emphasize high tension and eco-friendliness. In order to improve the coating roughness to improve the technology development is very low.

The present invention was created to overcome many of the limitations of the prior art as described above, by mixing the particles of the colloidal silica, which is the main component of the oriented electrical steel sheet tension coating agent with a fine size of more than 30% of the present, thereby filling the surface Tension coating composition for oriented electrical steel sheet to improve the electrical insulation and film gloss by maximizing the effect and adjusting the composition ratio of the components constituting the metal phosphate to improve the electrical insulation and the gloss of the coating, and the method of forming the insulating coating using the same It is an object to provide a grain-oriented electrical steel sheet having an insulating coating formed by the method.

The present invention as a means for achieving the above object, in the insulating film treatment process of a grain-oriented electrical steel sheet as a oriented electrical steel sheet tension coating agent mainly composed of metal phosphate, colloidal silica, the metal phosphate is a magnesium phosphate monobasic ( Mg (H ₂ PO ₄ ) ₂ ) and mono aluminum phosphate (Al (H ₂ PO ₄ ) ₃ ) are mixed liquids; With respect to the metal phosphate solution 100g, it provides a tension coating composition for a grain-oriented electrical steel sheet excellent in gloss and insulation, characterized in that it comprises a colloidal silica solid content of 30 ~ 60g having a particle size of 5 ~ 15nm.

At this time, the metal phosphate mixture is composed of 25 to 90 g of the first magnesium phosphate, 10 to 75 g of the first aluminum phosphate mixed with the ratio of the first magnesium phosphate and the first aluminum phosphate to 100g total composition. It also has its features.

In addition, the colloidal silica is 5nm (A), 7nm (B), 15nm (C) is composed of a mixture of A, B, C having a different particle size, the composition ratio of A, B, C is 1: It is also characterized by mixing at a weight ratio of 1: 0, 0: 1: 1, 1: 1: 2.

In addition, the present invention provides a method for forming an insulating coating on a grain-oriented electrical steel sheet; The tension coating composition described above on the surface of the grain-oriented electrical steel sheet is applied over a range of 0.5 to 6.0 g / ㎡, and baked and baked for 10 to 50 seconds at 800 ~ 900 ℃ to form an insulating film, gloss and insulation properties The present invention also provides a method for forming an insulating coating using an excellent tensile coating composition for electrical steel sheet.

In addition, the present invention provides a grain-oriented electrical steel sheet having an insulating coating formed on the surface of the grain-oriented electrical steel sheet by the method described above; The insulating film also provides a grain-oriented electrical steel sheet, characterized in that the glossiness is maintained at 45-53% while having an insulation of 90 mA or less.

According to the present invention, by improving the drying rate of the coating agent by varying the composition ratio of the metal phosphate, which is the main component of the oriented electrical steel sheet tension coating agent, it is possible to solve the problem of poor insulation due to undrying, and to remove the particles of colloidal silica By lowering the coating roughness in combination with a fine size of 30% or more, the effect of ultimately improving the electrical insulation and the gloss of the film can be obtained.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

The present invention is characterized by improving the electrical insulation in the manufacture of the tension coating agent for oriented electrical steel sheet to reduce the interlayer eddy current loss and to improve the surface gloss to improve the workability at the time of laminating transformers and at the same time to enhance the image of the product.

As described above, the commercialized high-strength oriented electrical steel sheet has been commercialized, and the high tensile strength of the final insulating film has been pursued. Accordingly, a new functional role of improving the magnetic properties has been added. As a result, the electrical insulating property of the oriented electrical steel sheet has been added. The role of the tension coating is very large.

These oriented electrical steel sheets are provided in coil form to customers who manufacture transformers, which are then reworked to meet the transformer specifications.

In this way, a transformer is manufactured by stacking sheets of reprocessed sheets. If the surface roughness is large during lamination, workability decreases due to friction between the steel sheets and the steel sheets.

In this case, the friction between the steel plate and the steel plate can be reduced by applying a beautiful surface coating, and at the same time, it can give a high-quality image to the product by giving gloss on the surface.

In consideration of such a situation, the main component of the tension coating agent according to the present invention is a colloidal silica which gives a coating tension, a coating agent, and a metal phosphate (magnesium phosphate (Mg (H ₂ PO ₄ ) ₂ ) which imparts adhesion to the interface of the steel sheet. And monoaluminum phosphate (Al (H ₂ PO ₄ ) ₃ ) mixture), CrO ₃ and other minor additives to enhance functionality.

In this case, colloidal silica uses basic colloidal silica having excellent film tension and relatively low manufacturing cost, and does not have good compatibility with acidic metal phosphate used as a binder of the tension coating agent, thereby causing gelation.

In this case, the use of chromium oxide prevents gelation when the two components are mixed and allows the coating to have a stable liquid phase.

In addition, in order to improve the insulation and surface gloss of the tension coating agent, it is necessary to consider the components of the tension coating and the drying mechanism, and present a fundamental technique.

Therefore, the present inventors solved the problems by proposing the following technique.

First, attention was paid to the relationship between the drying mechanism and the electrical insulation of each of the tension coating agent components. As mentioned above, the coating consists of water and the water is composed of water added to balance the overall gravity with the water of each component itself. The inventors noticed the difference in the drying mechanism between these components as well as the insulation deterioration when the drying was not complete.

In particular, the drying rate of the metal phosphate, ie, the first magnesium phosphate (Mg (H ₂ PO ₄ ) ₂ ) phosphate in the coating agent is inferior to the other components, and therefore the constituent ratio of the metal phosphate in the coating component of the aluminum phosphate (Al (H ₂ PO ₄ ) ₃ ) Mainly designed to improve the drying ability of the coating agent.

Second, by reducing the particle size of the colloidal silica, the main component of the tension coating agent to improve the friction reduction and gloss by improving the coating roughness. Colloidal silica forms a ceramic layer with a low thermal expansion coefficient upon firing of the coating agent to impart a tensile stress to the material, and the amount of the colloidal silica forms an appropriate ceramic layer when the content is 30 g or less based on 100 g of phosphate solution. It is not enough to impart tensile stress to the material, the solid content is increased in the coating agent at 60g or more to reduce the surface quality of the steel sheet.

However, colloidal silica, in addition to imparting tensile stress, influences the surface roughness after coating formation. Particularly, the colloidal silica has been found to have a decisive role in coating roughness. Therefore, in the present invention, the relationship between the coating roughness and the glossiness of the particle size was obtained, and it was found that the greatest effect was obtained when using a size smaller than twice the particle size of colloidal silica currently used.

In addition, as the demand for high power transformers increases recently, the size of the steel sheets increases, and the insulation requirements between steel sheets stacked correspondingly become more stringent. In order to improve the electrical insulation of the coating agent, analysis of the factors affecting the insulation is required.

The present invention found that the electrical insulation by the coating is reduced when the coating is insufficient drying through the experimental relationship with the drying temperature for this purpose.

On the basis of this, increasing the drying temperature of the drying furnace is a common method for sufficient drying. However, the energy consumption for producing the product increases when the drying furnace is increased, thus not only increasing the production cost but also additional equipment in case the capacity of the drying furnace is insufficient. In order to make an investment, the present invention contemplated a method capable of complete drying without increasing the drying temperature or improving the drying capacity of the drying furnace.

Thus, the difference in the drying mechanism between the coating components was analyzed. To determine the drying rate for each coating component, colloidal silica was added sequentially in order of phosphate and water for dilution of the coating agent, and the drying temperature was 800-900 ° C. Table 1 shows the amount evaporated after drying at 850 ° C. over time.

As shown in Table 1, colloidal silica dries almost completely in a short time, whereas phosphate does not completely dry the water present in the phosphate until 20 seconds before it can evaporate the water present in the component. there was.

At this time, in Table 1, the closer to 0, the undried water content means perfect drying.

Coating Ingredient Theoretical water content
(%) Water content according to drying time Undried Water Content
(%) 15 seconds 60 seconds Aluminum phosphate 42 40.2 41.8 0.2 Magnesium phosphate 38.8 40.1 1.9 Colloidal silica 70 29.8 30.0 0 Aluminum Phosphate +
Colloidal silica 57 55.2 56.4 0.6 Magnesium Phosphate +
Colloidal silica 52.5 54.6 2.4. Aluminum Phosphate +
Colloidal Silica +
Dilution water 72 68.0 71.0 1.0 Magnesium Phosphate +
Colloidal Silica + Dilution Water 65.4 68.2 3.8

At this time, as shown in Table 1, there may be various reasons for the phosphate is undried, firstly, the drying mechanism of the phosphate itself is different from the drying mechanism of the components containing the general water

-Low temperature (coating agent temperature, ≤ 550 ℃)

Phosphate: 2Al (H ₂ PO ₄ ) ₃ → Al ₂ (H ₂ P ₂ O ₇ ) ₃ + 3H ₂ O ↑

Colloidal silica: nSiO2 + H ₂ O → nSiO2 + H ₂ O ↑

Coating diluent additive: H ₂ O ↑

-High temperature (coating agent temperature, ≥ 650 ℃)

Phosphate: nAl ₂ (H ₂ P ₂ O ₇ ) ₃ → [Al (PO ₃ ) ₃ ] _2n + 3nH ₂ O ↑

Looking at the above chemical formula, the water contained in each component in a low temperature state is generally evaporated at 100 ° C. or higher as it is conceived, and only the solid component included in each component is present.

However, in the case of the metal phosphate, there is conventional water which is evaporated at about 100 ° C, and in addition, there is water which is released into the water as the chemical reaction proceeds as the temperature rises.

Since such water usually exits at or above 650 ° C., the temperature of the drying furnace should be at least 650 ° C. or higher, and since it is related to the reaction time of phosphate, it is necessary to stay at least a certain time in the drying furnace to achieve perfect drying.

In addition, to determine the drying rate according to the type of metal phosphate, the difference between aluminum phosphate and magnesium phosphate was confirmed as shown in Table 1, and as a result, the drying rate of magnesium phosphate in the same metal phosphate is slower than that of aluminum phosphate, thus forming a coating agent. Lowering the composition of phosphate was found to be advantageous for drying.

In particular, minimizing the ratio of magnesium phosphate in the metal phosphate could be expected to increase the drying rate of the coating without increasing the temperature of the drying furnace (see Table 2 described later).

As described above, a customer who manufactures a transformer or a generator receives a directional electrical steel sheet in coil form from a steel company, and the provided electrical steel sheet is reworked to meet the transformer or generator specifications. In order to manufacture transformer or generator by stacking sheet of reprocessed sheet like this, a high-voltage transformer or generator depends on a large part of lamination during manual lamination. Therefore, if the surface roughness is large during lamination, work is caused by friction between steel sheet and steel sheet. Sex will be reduced. In this case, the friction between the steel plate and the steel sheet can be reduced by applying a beautiful surface coating, and at the same time, it can give a high-quality image to the product by giving gloss to the surface.

After coating, the roughness by the coated surface may be expressed as shown in the accompanying drawings.

[Reference Drawing]

As shown in the reference figure, when the coating agent is applied and dried, the water contained in the coating agent in the drying process is evaporated and only the solid component remains to exist as shown in the figure.

As such, the surface roughness after coating depends on the solid component of the coating agent present on the surface after drying, and when the surface roughness is very beautiful, the diffuse reflection can be reduced, and thus the glossiness is improved.

In the present invention, as a result of closely examining the relationship between the coating surface state and the coating component, it was found that colloidal silica is a very important factor that influences the coating roughness.

Colloidal silica acts to impart tensile stress to the material by forming a ceramic layer with a low coefficient of thermal expansion when the coating agent is baked. If the amount is too small compared to the phosphate solution, colloidal silica does not form an appropriate ceramic layer to impart tensile stress to the material. If the amount is too low, the amount of solid content increases in the coating agent, which lowers the surface quality of the steel sheet.

However, colloidal silica, in addition to imparting tensile stress, influences the surface roughness after coating formation. Particularly, the colloidal silica has been found to have a decisive role in coating roughness.

Therefore, in this study, the relationship between the coating roughness and glossiness for the particle size was obtained, and it was found that the greatest effect was obtained when using a size smaller than twice the particle size of colloidal silica currently used. .

In the case of the coating agent prepared as described above, adhesion between the coating and the steel sheet is also improved, thereby exerting an effect of improving tensile stress, which is the main purpose of the coating agent.

The effect of improving the tensile stress due to the coating due to the improved adhesion is expressed by Equation 1 and is well represented in the inventors' previous research (see Patent No. 0966819).

+ Adhesion effect .......(식 1)

+ Adhesion effect ....... (Equation 1)

As shown in Equation 1, in addition to the chain reaction of silica generated at a high temperature of 800 ° C. or higher during drying of the coating agent, a solid film forming process by a complex chemical reaction between components that may occur at low temperatures, and the resulting material are used as the base material and the coating agent. It can be seen that the adhesion can be further improved through the reaction with the metal phosphate acting as a binder.

Based on this, the colloidal silica used in the present invention forms a ceramic layer having a low coefficient of thermal expansion upon firing of the coating agent to impart tensile stress to the material, and the amount of the colloidal silica is solid when the solid content is 100 g of the phosphate solution. It was found that it is very advantageous to add 30 ~ 60g, and maintain the drying temperature at 800-900 ℃.

Here, the reason for limiting the numerical value is as described above.

Particularly, in the case of the metal phosphate, as shown in Example 1 to be described later, when the mixed solution of the first magnesium phosphate and the first aluminum phosphate is used, the ratio of the first metal phosphate / aluminum monophosphate is 100 g of the total metal phosphate solution. As a reference, 25 to 90 g of magnesium phosphate and 10 to 75 g of aluminum phosphate were mixed and maintained to be 100 g in total, and it was confirmed that the most suitable for achieving the object of the present invention. Shall be.

After applying the tension coating composition composed of such a composition to the dry film coating amount of 0.5 ~ 6.0 g / ㎡, especially 4.0g / ㎡ on the surface of the grain-oriented electrical steel sheet, and then dried for 10 to 50 seconds in the temperature range of 800-900 ℃ By baking, the present invention can form the desired insulating film, and furthermore, the solution temperature of the tension coating agent composition should be managed at 20 ± 5 ℃ to realize the optimum coating amount of 0.5 ~ 6.0 g / ㎡.

Herein, when the coating amount is 0.5 g / m 2 or less, the insulation is insignificant, and when the coating amount is 6.0 g / m 2 or more, it is difficult to form a solid film due to the problem of film drying due to over-coating and cracks caused by the film weight.

In addition, the drying temperature of 800 ℃ or less is suspected that the drying of the phosphate in the component is suspected, and relatively above 900 ℃ is based on drying under the above temperature conditions due to the film color change due to deterioration of the organic emulsion in the component.

In addition, when the temperature of the tension coating agent is controlled below 15 ° C, the viscosity increases, so that it is difficult to manage a constant coating amount. When the temperature exceeds 25 ° C, the gelation phenomenon of the colloidal silica, which is a main component of the coating agent, is accelerated, resulting in deterioration of surface quality. Therefore, the temperature should be managed in the above range.

In particular, when the insulating film is formed on the surface of the grain-oriented electrical steel sheet by this method, the insulating film can maintain the glossiness of 45% or more while having an insulating property of at least 90 mA or less, as shown in Table 3 below. .

Hereinafter, examples will be described.

Example 1

It is a test specimen made of a grain-oriented electrical steel sheet (300 × 60mm) containing 3.1% of Si in a weight ratio and having a primary thickness of 0.23mm finished sheet, and dried at 850 ° C. for 30 seconds. Due to the addition of tensile stress due to the bending in one direction, the degree of bending can be measured to evaluate the tension caused by the coating.

The evaluation method is as follows.

SRA was heat-treated at 750 ℃ for 2 hours in a dry 100% N ₂ gas atmosphere. Insulation is expressed as the received current value when the input is 0.5V, 1.0A under 300PSI pressure. Is shown as the minimum arc diameter without film peeling when bent 180 ° in contact with an arc of 10, 20, 30 to 100 mm, and surface gloss was measured using a surface gloss meter, and the light incident on the surface was viewed as 100. The degree of reflection by the surface is shown in%.

In order to improve the insulation and glossiness of the tension coating agent, first, by adjusting the magnesium phosphate (Mg (H ₂ PO ₄ ) ₂ ) phosphate component, which is a main component that slows down the drying speed and causes incomplete drying, thereby lowering the insulation. Metal phosphates were prepared.

The coating agent thus prepared was coated with 4 g / m 2 on the specimen, and then insulation and coating tension were measured. At this time, as shown in Table 2, when the Mg ratio of the metal phosphate composition ratio is raised, the insulation and coating tension are lowered as expected. As described above, the first magnesium phosphate has a lower drying speed than aluminum monophosphate and thus prevents other components of the coating from completely drying in the drying furnace, and serves as a binder between the coating agent and the steel sheet. Failure to perform the phosphate's original function is expected to lead to a decrease in adhesion and coating tension.

Therefore, when referring to Table 2, since the specimen 4 condition is the condition of the current normal tension coating agent, in order to reinforce the insulation of the current tension coating agent, all of the specimens 1, 2, and 3 conditions can be used. Sticky defects may occur due to sensitivity to humidity present in the air.

Accordingly, in the present invention, the conditions of the specimen 3 were used as a reference, and the method of increasing the gloss by lowering the coating roughness based on the component ratio of the standard was sought.

Psalter
number Metal phosphate
(100 g) Silica
(g) CrO3
(g) Solid silica
(g) Insulation
(mA) Coating tension
(kgf / mm ² ) Sticky Castle Mg Al One 0 100 48 3 2.5 95 0.45 sticky 2 10 90 48 3 2.5 110 0.42 sticky 3 25 75 48 3 2.5 150 0.41 Good 4 50 50 48 3 2.5 250 0.39 Good 5 75 25 48 3 2.5 270 0.38 Good 6 90 10 48 3 2.5 298 0.36 Good 7 100 0 48 3 2.5 310 0.36 Good

In addition, the coating agent was prepared by variously applying the particle size of the colloidal silica based on the basic component system obtained through Table 2, and the surface property was confirmed after applying a predetermined amount of the coating agent thus prepared to the specimen, which is shown in Table 3. .

As shown in Table 3, when the particle size of the colloidal silica is small it can be seen that the coating roughness is very low, thereby improving the gloss.

However, when only colloidal silica with a very small particle size was used to increase the glossiness, insulation was found to be relatively degraded.

Thus, coatings were prepared by mixing different types of colloidal silicas with different particle sizes (Psalms 2-5 ~ 2-12). Even better, the polished specimen was very beautiful.

In particular, when the particle size of the colloidal silica of the present invention, that is, colloidal silica of 5 ~ 15nm, such as those having a particle size of 5nm, 7nm, 15nm of colloidal silica 1: 1: 0, 0: 1: 1, 1: Specimens 2-5, Specimens 2-6, and Specimens 2-10, which are examples mixed at a weight ratio of 1: 2, had an insulating property of 90 mA or less, and the surface gloss was more than 45%, indicating that the gloss was excellent. Usually has 250mA insulation and 20% gloss).

The reason for this is that the smaller particle size of the colloidal silica is arranged between the silica particles having a larger particle size, thereby increasing the packing property and improving the compactness.

Psalter
number Metal phosphate Colloidal Silica (Particle Size) Insulation
(mA) Surface roughness
(mm) Glossiness
(%) Mg Al A
(5 nm) B
(7 nm) C
(15 nm) D
(20 nm) 2-1 25 75 48 - - - 140 0.20 55 2-2 48 125 0.21 53 2-3 48 150 0.38 20 2-4 48 230 0.36 19 2-5 24 24 90 0.20 53 2-6 24 24 50 0.25 45 2-7 24 24 135 0.30 25 2-8 24 24 100 0.28 30 2-9 24 24 111 0.29 28 2-10 12 12 24 25 0.22 50 2-11 12 12 24 38 0.27 42 2-12 12 12 24 46 0.28 33 Normal 50 50 - - 48 - 250 0.38 20

Claims (5)

As a tension coating agent for oriented electrical steel, which is mainly composed of metal phosphate and colloidal silica in the insulation coating process of oriented electrical steel sheet,
The metal phosphate is a mixed solution of magnesium phosphate (Mg (H ₂ PO ₄ ) ₂ ) and aluminum phosphate (Al (H ₂ PO ₄ ) ₃ );
To 100g of the metal phosphate solution, it comprises a colloidal silica solid content of 30 ~ 60g having a particle size of 5 ~ 15nm, the colloidal silica solid content is characterized in that more than 50% by weight has a particle size of 5 ~ 7nm. Tension coating agent composition for a grain-oriented electrical steel sheet excellent in gloss and insulation.
As a tension coating agent for oriented electrical steel, which is mainly composed of metal phosphate and colloidal silica in the insulation coating process of oriented electrical steel sheet,
The metal phosphate is a mixed solution of magnesium phosphate (Mg (H ₂ PO ₄ ) ₂ ) and aluminum phosphate (Al (H ₂ PO ₄ ) ₃ );
To 100g of the metal phosphate solution, it comprises a colloidal silica solid content of 30 ~ 60g having a particle size of 5 ~ 15nm,
The metal phosphate mixed solution is composed of 25 to 90 g of first magnesium phosphate and 10 to 75 g of first aluminum phosphate based on a ratio of 100 g of the metal phosphate mixture to the total amount of 100 g of the magnesium phosphate and the first aluminum phosphate. Tension coating agent composition for a grain-oriented electrical steel sheet excellent in gloss and insulation.
As a tension coating agent for oriented electrical steel, which is mainly composed of metal phosphate and colloidal silica in the insulation coating process of oriented electrical steel sheet,
The metal phosphate is a mixed solution of magnesium phosphate (Mg (H ₂ PO ₄ ) ₂ ) and aluminum phosphate (Al (H ₂ PO ₄ ) ₃ );
To 100g of the metal phosphate solution, it comprises a colloidal silica solid content of 30 ~ 60g having a particle size of 5 ~ 15nm,
The colloidal silica is composed of 5nm (A), 7nm (B), 15nm (C) is a mixture of A, B, C having a different particle size,
Composition ratio of the A, B, C is a tension coating agent composition for a grain-oriented electrical steel sheet excellent in gloss and insulation, characterized in that mixed in a weight ratio of any one of 1: 1: 0, 0: 1: 1, 1: 1: 2.
A method of forming an insulating coating on a grain-oriented electrical steel sheet;
The tension coating composition according to any one of claims 1 to 3 is applied to the surface of the grain-oriented electrical steel sheet over a range of 0.5 to 6.0 g / m 2, and dried and baked for 10 to 50 seconds at 800 to 900 ° C. to form an insulating coating. An insulating film forming method using a tension coating agent composition for a grain-oriented electrical steel sheet excellent in gloss and insulation.
In the grain-oriented electrical steel sheet having an insulating coating formed on the surface of the grain-oriented electrical steel sheet by the method according to claim 4;
The insulating coating is a grain-oriented electrical steel sheet, characterized in that the glossiness is maintained at 45-53% while having an insulation of 90mA or less.