KR20230095279A - Insulation coating composition for electrical steel sheet, electrical steel sheet, and method for manufacturing the same - Google Patents

Abstract

(단, 화학식 1에서 R¹ 내지 R³은 각각 독립적으로, 수소, 할로겐 원자, 직쇄형 또는 분지형 알킬기, 시클로 알킬기, 알케닐기, 알키닐기, 아릴기, 헤테로아릴기, 알콕시기 또는 아미노알킬기를 나타낸다.)An insulation coating composition for an electrical steel sheet according to an embodiment of the present invention includes an emulsion resin containing 17% by weight or less of a repeating structure represented by Formula 1 below.
[Formula 1]

(However, in Formula 1, R ¹ to R ³ are each independently hydrogen, a halogen atom, a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group indicate.)

Description

Electrical steel sheet insulation coating composition, electrical steel sheet, and manufacturing method thereof

An embodiment of the present invention relates to an electrical steel sheet insulation coating composition, an electrical steel sheet, and a manufacturing method thereof. Specifically, it relates to an electrical steel sheet insulation coating composition having improved insulation using an emulsion resin containing acrylamide, an electrical steel sheet, and a manufacturing method thereof.

Electrical steel is a product used as a material for transformers, motors, and electric machines. Unlike general carbon steel, which places importance on workability such as mechanical properties, electrical steel is a functional product that places importance on electrical characteristics. Required electrical properties include low iron loss, high magnetic flux density, magnetic permeability and space factor.

Electrical steel sheet is again divided into grain-oriented electrical steel sheet and non-oriented electrical steel sheet. Grain-oriented electrical steel sheet is an electrical steel sheet with excellent magnetic properties in the rolling direction by forming the Goss texture ({110}<001> texture) throughout the steel sheet using the abnormal grain growth phenomenon called secondary recrystallization. A non-oriented electrical steel sheet is an electrical steel sheet having uniform magnetic properties in all directions on a rolled sheet.

Electrical steel sheets are divided into two types: stress relief annealing (SRA) is required to improve magnetic properties after punching, and SRA is omitted if the cost loss due to heat treatment is greater than the effect of magnetic properties by SRA. are using

On the other hand, insulation film formation is a process corresponding to the final manufacturing process of a product. In addition to the electrical properties that normally suppress the occurrence of eddy currents, continuous punching to suppress wear of the mold After the SRA process, which restores workability and magnetic properties by removing the processing stress of the steel sheet, the sticking resistance and surface adhesion that do not adhere between iron core steel sheets are required. In addition to these basic properties, excellent application workability of the coating solution and solution stability that can be used for a long time after mixing are also required. Coating solutions used for this purpose include chromium coating based on chromic acid and phosphate coating based on phosphate.

The main purpose of the insulating coating is interlayer insulation between laminated iron plates. However, with the expansion of the use of small electric machines, coating performance advantageous to processability, weldability, and corrosion resistance as well as insulation has been evaluated as major physical properties. came to demand

As mentioned above, non-oriented electrical steel sheet is currently riding the wave of high-end quality due to the development of high-efficiency motors in line with the government's low-carbon policy. do. In particular, excellent insulation that can maximize motor performance by minimizing eddy current loss is a must. In order to secure excellent insulation, the method of increasing the coating thickness is the most common method. However, when the coating thickness is increased, there is a disadvantage in that required characteristics such as weather resistance, weldability, heat resistance, adhesion before and after SRA, and stacking factor are inferior.

An embodiment of the present invention provides an electrical steel sheet insulation coating composition, an electrical steel sheet, and a manufacturing method thereof. Specifically, an electrical steel sheet insulation coating composition with improved insulation using an emulsion resin containing acrylamide, an electrical steel sheet, and a manufacturing method thereof are described.

An insulation coating composition for an electrical steel sheet according to an embodiment of the present invention includes an emulsion resin containing 17% by weight or less (excluding 0% by weight) of a repeating structure represented by Formula 1 below.

[Formula 1]

(However, in Formula 1, R ¹ to R ³ are each independently hydrogen, a halogen atom, a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group indicate.)

The emulsion resin may include 1 to 15% by weight of the repeating structure represented by Chemical Formula 1.

Emulsion resin refers to a resin that does not cause layer separation even if it is left for a long time after a resin incompatible with a solvent is mixed with a solvent, dispersed and stabilized by other methods such as surfactant, electrical force, and physical force.

Based on 100 parts by weight of the solid content of the composition, 10 to 50 parts by weight of emulsion resin; and 50 to 90 parts by weight of at least one of phosphoric acid and metal phosphate; can include

The metal phosphate may include one or more of Al, Co, Ca, Zn, and Mg.

An electrical steel sheet according to an embodiment of the present invention includes an electrical steel sheet substrate and an insulating film positioned on a surface of the electrical steel sheet substrate, and the insulating coating contains carbon agglomerates in a thickness range of 30 to 70% with respect to a cross section including a thickness direction of the electrical steel sheet. Including area %, the average particle diameter of the carbon agglomerates is 50 to 300 nm.

The carbon agglomerate may contain 40 to 60% by weight of carbon.

The insulating film may include pores at 10 area% or less with respect to the cross section including the thickness direction of the electrical steel sheet.

A method for manufacturing an electrical steel sheet according to an embodiment of the present invention includes preparing a substrate for an electrical steel sheet; The method includes applying an insulating coating composition to a surface of an electrical steel sheet substrate and heat-treating the electrical steel substrate coated with the insulating coating composition.

According to one embodiment of the present invention, by including the emulsion resin containing acrylamide, an appropriate carbon agglomerate is formed in the insulation film, and sufficient insulation can be obtained even when a thin insulation film is formed.

1 is a schematic view of a cross section of an electrical steel sheet according to an embodiment of the present invention.
2 is a TEM image and a carbon EDS mapping image of the insulating film prepared in Sample 1.
3 is a TEM image and a carbon EDS mapping image of the insulating film prepared in Sample 3.
4 is a TEM image and a carbon EDS mapping image of the insulating film prepared in Sample 5.

Terms such as first, second and third are used to describe, but are not limited to, various parts, components, regions, layers and/or sections. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is only for referring to specific embodiments and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. The meaning of "comprising" as used herein specifies particular characteristics, regions, integers, steps, operations, elements and/or components, and the presence or absence of other characteristics, regions, integers, steps, operations, elements and/or components. Additions are not excluded.

When a part is referred to as being “on” or “on” another part, it may be directly on or on the other part or may be followed by another part therebetween. In contrast, when a part is said to be “directly on” another part, there is no intervening part between them.

In the description of a group (atomic group) in this specification, the notation that does not describe substitution and unsubstitution includes those without substituents as well as those with substituents. For example, an "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

In the present specification, unless otherwise defined, "substitution" is a compound in which at least one hydrogen is a C1 to C30 alkyl group; C2 to C30 alkenyl group, C2 to C30 alkynyl group, C1 to C10 alkylsilyl group; C3 to C30 cycloalkyl group; C6 to C30 aryl group; C1 to C30 heteroaryl group; C1 to C10 alkoxy group; silane group; Alkylsilane group; an alkoxysilane group; amine group; Alkylamine group; Arylamine group; It means substituted with an ethyleneoxyl group or a halogen group.

In the present specification, "hetero" means an atom selected from the group consisting of N, O, S, and P, unless otherwise defined.

In the present specification, unless otherwise defined, "alkyl group" is a "saturated alkyl group" that does not contain any alkenyl group or alkynyl group; or an "unsaturated alkyl group" containing at least one alkenyl group or alkynyl group. The "alkenyl group" refers to a substituent in which at least two carbon atoms form at least one carbon-carbon double bond, and the "alkyne group" refers to a substituent in which at least two carbon atoms form at least one carbon-carbon triple bond. it means. The alkyl group may be branched, straight-chain or cyclic.

The alkyl group may be a C1 to C20 alkyl group, specifically, a C1 to C6 lower alkyl group, a C7 to C10 intermediate alkyl group, or a C11 to C20 higher alkyl group.

For example, a C1 to C4 alkyl group means that there are 1 to 4 carbon atoms in the alkyl chain, which is methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and t-butyl. indicates that it is selected from the group consisting of

Typical alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, ethenyl, propenyl, butenyl, cyclopropyl, cyclobutyl, cyclo There is a pentyl group, a cyclohexyl group, and the like.

"Aromatic group" means a substituent in which all elements of a cyclic substituent have p-orbitals, and these p-orbitals form conjugation. Specific examples include an aryl group and a heteroaryl group.

An "aryl group" includes a single ring or a fused ring, ie, a plurality of ring substituents that share adjacent pairs of carbon atoms.

"Heteroaryl group" refers to an aryl group including a heteroatom selected from the group consisting of N, O, S, and P in the aryl group. When the heteroaryl group is a fused ring, each ring may contain 1 to 3 hetero atoms.

Unless otherwise defined herein, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, or an aminoalkyl group is a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, An aryl group, a heteroaryl group, an alkoxy group, or an aminoalkyl group.

Although not defined differently, all terms including technical terms and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

An insulation coating composition for an electrical steel sheet according to an embodiment of the present invention includes an emulsion resin having a repeating structure represented by Formula 1 below.

[Formula 1]

(However, in Formula 1, R ¹ to R ³ are each independently hydrogen, a halogen atom, a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group indicate.)

In the case of a general emulsion resin, a large amount of resin monomer is included in the emulsion particles, and the resin monomer vaporizes during a heat treatment process after applying the insulation coating composition to form pores inside the insulation coating. The pores are deformed by pressurization during punching and welding, and cause deterioration of insulation.

In one embodiment of the present invention, by including the acrylamide repeating structure represented by Chemical Formula 1 in the emulsion resin, it is possible to prepare an emulsion resin having a solid structure in which no unreacted monomers remain and the polymerization reaction has completely occurred. If this emulsion resin is used, it is possible to synthesize an insulation coating composition in which the emulsion resin particles evenly distributed in the insulation coating cause a dielectric effect without being deformed by pressing.

The repeating structure represented by Chemical Formula 1 may be included in an amount of 17% by weight or less based on 100% by weight of the emulsion resin. When the repeating structure represented by Formula 1 is included too much, precipitation of the emulsion resin may occur, and a problem may occur in solution stability. More specifically, the repeating structure represented by Formula 1 may be included in an amount of 1 to 15% by weight based on 100% by weight of the emulsion resin.

In this emulsion resin, a strong intramolecular bond is formed by the amide monomer, so that the carbon aggregate in the insulating film is appropriately formed. This carbon agglomerate acts as a dielectric and helps to improve the insulating properties of the insulating film. Since the carbon agglomerate has been described in detail in the description of the electrical steel sheet to be described later, duplicate descriptions will be omitted.

In Formula 1, R ¹ to R ³ may each independently be hydrogen, a halogen atom, or a linear or branched alkyl group. More specifically, in Formula 1, R ¹ to R ³ may be hydrogen.

The emulsion resin may include one or more repeating units of epoxy, ester, acrylic, styrene, urethane, and ethylene in addition to the repeating unit represented by Chemical Formula 1. More specifically, the emulsion resin may include epoxy or acrylic repeating units.

In one embodiment of the present invention, emulsion resins are distinguished from dispersion resins. Specifically, emulsion resin is a resin that is incompatible with a solvent is mixed with a solvent, dispersed and stabilized by other methods such as surfactant, electrical force, physical force, etc. It is a resin that does not cause layer separation even when left for a long time. It is distinguished from dispersion resins that are compatible with solvents. Dispersion resins do not form carbon agglomerates in the insulating film and are superior to emulsion resins in terms of insulating properties.

The emulsion resin serves to impart adhesion to the steel sheet and insulation and flexibility of the insulating film. The emulsion resin may be included in an amount of 10 to 50 parts by weight based on 100 parts by weight of the solid content of the composition. If too little emulsion resin is included, it may be difficult to secure adhesion to the steel sheet and insulation of the insulating film. If too much emulsion resin is included, peeling of the insulation film may occur during the stress relief annealing process. More specifically, the emulsion resin may be included in an amount of 20 to 40 parts by weight based on 100 parts by weight of the solid content of the composition. Here, parts by weight means a weight relative to the weight of the solid content of the composition.

An insulation coating composition for an electrical steel sheet according to an embodiment of the present invention includes 50 to 90 parts by weight of at least one of phosphoric acid and a metal phosphate based on 100 parts by weight of the solid content of the composition.

Phosphoric acid or metal phosphate serves to impart insulation and adhesion to the film. The metal phosphate may include one or more types of metals among Al, Mg, Ca, Co, Zn, Zr, and Fe. Specific examples include aluminum phosphate, cobalt phosphate, calcium phosphate, zinc phosphate, magnesium phosphate, and the like. More specifically, the metal phosphate may include one or more metals selected from among Al and Mg.

The metal phosphate may be prepared by adding a metal hydroxide to a mixed solution of phosphoric acid and water and reacting at 80 to 90° C. for 6 to 10 hours. In some cases, one or more other metal phosphates may be synthesized and mixed.

Phosphoric acid or metal phosphate may be included in an amount of 50 to 90 parts by weight based on 100 parts by weight of the solid content of the composition. If too little phosphoric acid or metal phosphate is added, insulation and adhesion may be deteriorated. If too much phosphoric acid or metal phosphate is added, a mold deterioration problem may occur in the punching process. When phosphoric acid and metal phosphate are included at the same time, the total amount may be 50 to 90 parts by weight. More specifically, phosphoric acid or metal phosphate may be included in an amount of 60 to 80 parts by weight based on 100 parts by weight of the solid content of the composition.

The insulation coating composition for electrical steel sheet according to an embodiment of the present invention may further include 10 parts by weight or less of inorganic particles based on 100 parts by weight of the solid content of the composition.

The inorganic particles prevent precipitation or agglomeration of the insulation coating composition, and contribute to more excellent surface characteristics after stress relief annealing.

Inorganic particles may be added in combination with the emulsion resin. When the inorganic particles are added alone without binding to the emulsion resin, the inorganic particles aggregate with each other and do not disperse. The meaning of being bound to the emulsion resin means that the inorganic particles are substituted and bound to the functional group of the organic resin.

The inorganic particles may include one or more of SiO ₂ , Al ₂ O ₃ , TiO ₂ , MgO, ZnO, and ZrO ₂ . More specifically, at least one of SiO ₂ and TiO ₂ may be included.

The inorganic particles may have an average particle size of 10 to 50 nm. Appropriate dispersibility can be secured within the above range.

When the inorganic particles are further included, they may be further included in an amount of 10 parts by weight or less based on 100 parts by weight of the solid content of the composition. If too many inorganic particles are added, precipitation of the inorganic particles may occur due to lack of bonding sites in the emulsion resin.

The insulation coating composition according to an embodiment of the present invention may further include an oxidation accelerator. An example of an oxidation promoter may be sodium perborate (NaBO ₃ .4H ₂ O). The oxidation promoter may be included in an amount of 5 parts by weight or less based on 100 parts by weight of the solid content of the composition.

In addition to the above components, the insulation coating composition may include a solvent to facilitate application and uniformly disperse the components. The amount of the solvent is not particularly limited, but may include 50 parts by weight to 500 parts by weight based on the total solid content.

1 shows a schematic view of a cross section of an electrical steel sheet 100 according to an embodiment of the present invention. As shown in FIG. 1 , an electrical steel sheet 100 according to an embodiment of the present invention includes an electrical steel sheet substrate 10 and an insulating film 20 positioned on the electrical steel sheet substrate 10 .

As the electrical steel substrate 10, a general non-oriented or grain-oriented electrical steel sheet may be used without limitation. In one embodiment of the present invention, since the main configuration is to form the insulating film 20 of a special component on the electrical steel substrate 10, a detailed description of the electrical steel substrate 10 will be omitted.

The insulating coating 20 contains 30 to 70 area % of carbon agglomerates with respect to the cross section including the thickness direction of the electrical steel sheet, and the average particle diameter of the carbon agglomerates is 50 to 300 nm.

In one embodiment of the present invention, by appropriately forming the carbon agglomerate in the insulating film 20, the carbon agglomerate serves as a dielectric and sufficient insulation can be secured even when the insulating film 20 is formed with a small thickness.

The cross section including the thickness direction of the electrical steel sheet means a surface cut through the steel sheet parallel to the thickness direction. Specifically, it may be a surface perpendicular to the rolling direction (RD direction) or a surface perpendicular to the rolling vertical direction (TD direction).

The carbon agglomerate means a particle containing 40 to 60% by weight of carbon and carbon agglomerated to form particles. It is based on aggregates with a grain size of 10 nm or more in the cross section including the thickness direction of the electrical steel sheet. As a specific method for determining carbon agglomerates, when analyzing a cross section including the thickness direction of an electrical steel sheet with a SEM image, the electrical conductivity is low, so it is displayed in black compared to the surrounding area (the cross section is observed and is distinguished from pores where the inside is visible. ), when analyzed by TEM image, it is a part that is black compared to the surrounding area due to high electron permeability, and also, when analyzing the same part with carbon EDS mapping image, it can be judged as a brighter (higher C content) part than the surrounding area can In the case of pores, when the cross section including the thickness direction of the electrical steel sheet is analyzed with a TEM image, it is displayed in black compared to the surrounding area and is similar to a carbon agglomerate, but when the same area is analyzed with a carbon EDS mapping image, it is dark similar to the surrounding area (C content is low), so it is possible to distinguish. It contains 30 to 70 area % of carbon agglomerates, and the average particle diameter of the carbon agglomerates is 50 to 300 nm.

If the area ratio of the carbon agglomerate is too small, it is difficult to expect the effect of improving insulation due to the carbon agglomerate, and problems such as mold deformation occur during processing by the customer. If the area ratio of the carbon agglomerate is too large, a problem of peeling of the insulating film may occur during stress relief annealing at the customer company. If the average particle diameter of the carbon agglomerate is too small, it is difficult to expect an effect of improving insulation due to the carbon agglomerate. If the average particle diameter of the carbon agglomerate is too large, peeling problems due to poor adhesion after stress relief annealing may occur. More specifically, 30 to 50 area % of the carbon agglomerate may be included, and the average particle diameter of the carbon agglomerate may be 150 to 250 nm. The average particle diameter of carbon agglomerates means the number average particle diameter of carbon agglomerates, and assumes a virtual circle having the same area as the area occupied by the carbon agglomerates, and takes the diameter of the circle as the particle diameter.

As described above, in one embodiment of the present invention, pores in the insulating film 20 can be reduced by using an emulsion resin containing acrylamide. Specifically, the insulating film 20 may include pores at 10 area% or less with respect to a cross section including the thickness direction of the electrical steel sheet. The average particle diameter of the pores may be 50 to 300 nm. More specifically, it may contain 5 area% or less.

The thickness of the insulating film 20 may be 0.1 to 3.0 μm. When the thickness of the insulating film 20 is too thin, it is difficult to ensure adequate insulating properties. If the thickness of the insulating film 20 is too thick, the space factor may decrease. In one embodiment of the present invention, even if the insulating film 20 is formed with a thin thickness, proper insulation can be secured. More specifically, the thickness of the insulating film 20 may be 0.1 to 1.0 μm. More specifically, the thickness of the insulating film 20 may be 0.3 to 0.5 μm.

Insulation film 20 may maintain the solid component and content ratio in the composition of the above-described insulation film. Specifically, the insulating film 20 may include an emulsion resin including a repeating structure represented by Chemical Formula 1.

[Formula 1]

(However, in Formula 1, R ¹ to R ³ are each independently hydrogen, a halogen atom, a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group indicate.)

In addition, other components such as phosphoric acid, metal phosphate, and inorganic particles may be equally included, and since this has been described in detail in relation to the insulation coating composition, overlapping descriptions will be omitted.

A method for manufacturing an electrical steel sheet according to an embodiment of the present invention includes preparing a substrate for an electrical steel sheet; The method includes applying an insulating coating composition to a surface of an electrical steel sheet substrate and heat-treating the electrical steel substrate coated with the insulating coating composition.

First, an electrical steel sheet substrate is prepared. As the electrical steel substrate 10, a general non-oriented or grain-oriented electrical steel sheet may be used without limitation. In one embodiment of the present invention, since the main configuration is to form the insulating film 20 of a special component on the electrical steel substrate 10, a detailed description of the manufacturing method of the electrical steel substrate 10 will be omitted.

Next, an insulating coating composition is applied to the surface of the electrical steel substrate. Since the insulation coating composition has been described above, a detailed description thereof will be omitted.

to the next. The electrical steel sheet substrate coated with the insulating coating composition is heat-treated. Heat treatment temperature may be 300 to 750 ℃. If the temperature is too low, it takes a long time to form the film, and whitening may occur. If the temperature is too high, heat resistance and bluing resistance due to cracking may decrease.

Hereinafter, preferred embodiments of the present invention, comparative examples, and evaluation examples thereof are described. However, the following example is only a preferred embodiment of the present invention, but the present invention is not limited to the following example.

Example

When synthesizing an acrylic emulsion resin, an emulsion resin was prepared by adding an acrylamide monomer represented by the following chemical formula as a type of monomer. At this time, the addition amount of the acrylamide monomer was adjusted as shown in Table 1 below.

[chemical formula]

The dispersion resin of Comparative Example was prepared by increasing the dispersibility with the solvent by increasing the content of the acrylic acid monomer having a hydrophilic group.

A composition for forming an insulating coating composition was prepared by mixing the synthesized acrylic emulsion resin and aluminum phosphate in a weight ratio of 3:7.

A non-oriented electrical steel sheet (150 × 50 mm) containing 3.15 wt% of silicon (Si) in weight ratio and having a thickness of 0.27 mm was used as a specimen, and a solution prepared as shown in Table 1 was applied thereon with a bar coater (bar Coater and roll coater were applied to each prepared specimen to form a 0.5 μm film, maintained in a drying oven at a temperature range of about 500 ° C for 20 seconds, and then slowly cooled in air.

Solution stability was investigated by checking the presence or absence of precipitate while the solution was left for a week, and non-occurrence was marked as good (O) and occurrence was marked as poor (X).

Insulation properties were measured on the top of the coating using a Franklin measuring instrument according to the ASTM A717 international standard.

Carbon agglomerates are analyzed by TEM images and carbon EDS mapping images for cross sections perpendicular to the rolling vertical direction, and areas that are darker than the surroundings in the TEM image and have higher intensity of C than the surroundings in the carbon EDS mapping image are determined as carbon agglomerates, In the TEM image, the area that was darker than the surrounding area, but the intensity of C in the carbon EDS mapping image was similar to or lower than the surrounding area was determined as a stomata.

sample resin type Acrylamide content in resin
(weight%) solution stability carbon aggregate pore electricity
insulation
(Ω cm ² /lamination) area% Average particle diameter (nm) area% Average particle diameter (nm) One Dispersion - Good - - - - 13 2 Dispersion 5 Good - - - - 12 3 emulsion - Good - - 70 50 15 4 emulsion One Good 70 50 - - 25 5 emulsion 10 Good 40 200 - - 28 6 emulsion 15 Good 30 250 - - 25 7 emulsion 20 precipitation Does not form an insulating film

As shown in Table 1 and FIG. 2, in the case of samples 1 and 2 using a dispersion resin rather than an emulsion resin, no pores or carbon agglomerates were formed in the insulating film, and it could be confirmed that the insulation properties were relatively poor.

As shown in Table 1 and FIG. 3, in the case of sample 3 using an emulsion resin that does not contain acrylamide, a large number of pores are generated in the insulating film, carbon agglomerates are not properly formed, and it can be confirmed that the insulation is relatively poor. .

As shown in Table 1 and FIG. 4, in the case of Samples 4 to 6 using the emulsion resin appropriately containing acrylamide, carbon agglomerates were properly formed in the insulating coating, and it could be confirmed that the insulation properties were excellent.

The present invention is not limited to the above embodiments, but can be manufactured in a variety of different forms, and those skilled in the art to which the present invention pertains may take other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that it can be implemented as. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

100: electrical steel sheet 10: electrical steel sheet substrate
20: Insulation film

Claims (8)

An insulation coating composition for electrical steel sheet comprising an emulsion resin containing 17% by weight or less (excluding 0% by weight) of a repeating structure represented by Formula 1 below.
[Formula 1]

(However, in Formula 1, R ¹ to R ³ are each independently hydrogen, a halogen atom, a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group indicate.) According to claim 1,
The emulsion resin is an insulating coating composition for electrical steel sheet containing 1 to 15% by weight of the repeating structure represented by Formula 1. According to claim 1,
Based on 100 parts by weight of the solid content of the composition,
10 to 50 parts by weight of the emulsion resin; and
50 to 90 parts by weight of at least one of phosphoric acid and metal phosphate; An insulating coating composition for electrical steel comprising: According to claim 3,
The metal phosphate is an insulating coating composition for electrical steel sheet containing at least one of Al, Co, Ca, Zn and Mg. Electrical steel substrate and
Including an insulating film located on the surface of the electrical steel substrate,
The electrical steel sheet of claim 1 , wherein the insulating coating contains 30 to 70 area % of carbon agglomerates with respect to a cross section including a thickness direction of the electrical steel sheet, and the average particle diameter of the carbon agglomerates is 50 to 300 nm. According to claim 5,
The carbon aggregate is an electrical steel sheet containing 40 to 60% by weight of carbon. According to claim 5,
The electrical steel sheet wherein the insulating film contains pores at 10 area% or less with respect to a cross section including a thickness direction of the electrical steel sheet. Preparing an electrical steel base material;
Applying the insulation coating composition according to any one of claims 1 to 4 on the surface of the electrical steel substrate; and
A method of manufacturing an electrical steel sheet comprising the step of heat-treating the electrical steel sheet substrate coated with the insulation coating composition.

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