WO2020027545A1 - Insulating coating composition for electrical steel sheet, and electrical steel sheet comprising insulating coating - Google Patents

Abstract

One embodiment of the present invention comprises: an electrical steel sheet material; and an insulating coating which is on one or both sides of the electrical steel sheet material, wherein the insulating coating comprises a silane compound and a metal hydroxide.

Description

Electrical steel sheet including insulating film composition for electrical steel sheet and insulating film

The present invention relates to an electrical steel sheet comprising an insulating coating composition for electrical steel sheet and an insulating coating. More specifically, the present invention relates to an electrical steel sheet including an insulating coating composition and an insulating coating for an electrical steel sheet having excellent heat resistance and thermal conductivity during stress relief annealing using a silane compound including a specific chemical structure.

The insulating film of an electrical steel sheet used for a motor, a transformer, etc. requires not only an interlayer resistance but various characteristics. For example, it is convenience in work forming, storage, stability in use, etc. Moreover, since electrical steel sheets are used for various uses, development of various insulating films is performed according to the use.

For example, when the electrical steel sheet is subjected to punching, shearing, bending, or the like, magnetic properties deteriorate due to residual deformation. Therefore, stress relief annealing (SRA) is sometimes performed at high temperature to recover the deteriorated magnetic properties. Therefore, the insulating film needs heat resistance that does not peel off during stress relief annealing and maintains intrinsic electrical insulation.

As a known insulating coating composition, chromic anhydride, magnesium oxide, an acrylic resin, or an acrylic-styrene copolymer resin is mixed and applied to improve corrosion resistance and insulation. However, such an insulating coating composition has a limit to satisfy heat resistance during stress relief annealing that is recently required.

In addition, a method of improving adhesion during stress relief annealing using metal phosphate as a main component of the insulating coating composition has been proposed. However, this method has a problem that whitening defects are generated on the surface due to the characteristics of phosphate having strong absorption resistance, and dust is generated during processing of the product, and heat resistance is rather inferior to a portion where whitening defects have occurred.

Provided is an electrical steel sheet comprising an insulating coating composition for electrical steel sheet and an insulating coating. More specifically, using an silane compound containing a specific chemical structure, to provide an electrical steel sheet comprising an insulating coating composition and an insulating coating for electrical steel sheet excellent in heat resistance and thermal conductivity during stress relief annealing.

An electrical steel sheet according to an embodiment of the present invention includes an electrical steel sheet and an insulating film located on one or both sides of the electrical steel sheet substrate, the insulating film includes a silane compound and a metal hydroxide represented by the following formula (1).

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

The silane compound may be represented by the following formula (2).

(In Formula 2, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cyclo alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L ¹ is directly A bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

Silane compounds include triacetoxy (methyl) silane, triacetoxy (vinyl) silane, dimethyldimethacroyloxy-1-ethoxysilane (Dimethyl-di (methacroyloxy-1-) ethoxy) silane) and 3- (trimethoxysilyl) propylmethacrylate (3- (trimethoxysilyl) propylmethacrylate).

The metal hydroxides are Ni (OH) ₂ , Co (OH) ₂ , Cu (OH) ₂ , Sr (OH) ₂ , Ba (OH) ₂ , Pd (OH) ₂ , In (OH) ₃ , (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ , Bi (OH) ₃ and Sn (OH) ₂ may be included.

The insulation coating further includes metal nitride, and may include 0.1 to 40 wt% of the metal nitride, 25 to 75 wt% of the silane compound, and 0.5 to 60 wt% of the metal hydroxide.

The metal nitride may include at least one of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .

The electrical steel sheet may satisfy the following general formula (1).

[Formula 1]

20≤ TC ≤ 200 W / mK

(In Formula 1, TC represents a thermal conductivity value measured by PPMS (Physical Property Measurement System) after induction heating of a specimen of 600 × 400mm 230 ℃.

The electrical steel substrate is C: 0.01% by weight or less, Si: 6.0% by weight or less, P: 0.5% by weight or less, S: 0.005% by weight or less, Mn: 0.1 to 1.0% by weight, Al: 0.40 to 2.0% by weight, N: 0.005% by weight or less, Ti: 0.005% by weight or less, and Sb, Sn, Ni or a combination thereof: 0.01 to 0.15% by weight, and may include Fe and unavoidable impurities.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a silane compound represented by the formula (1) and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

The metal nitride may further be included, and the solid content may include 0.1 to 40 wt% of the metal nitride, 25 to 75 wt% of the silane compound, and 0.5 to 60 wt% of the metal hydroxide.

The metal nitride may include at least one of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .

Method of manufacturing an electrical steel sheet according to an embodiment of the present invention comprises the steps of hot rolling the slab to produce a hot rolled plate, after cold rolling, to prepare a steel sheet to complete the final annealing; And applying an insulating coating composition to a steel sheet to form an insulating coating, wherein the insulating coating composition includes a silane compound represented by the following Chemical Formula 1 and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

The electrical steel sheet on which the insulating coating is formed may satisfy the following general formula (1).

[Formula 1]

20≤ TC ≤ 200 W / mK

(In Formula 1, TC represents a thermal conductivity value measured by PPMS (Physical Property Measurement System) after induction heating of a specimen of 600x400mm 230 ℃.)

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention is a silane compound represented by the formula (1) silane compound; And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, a straight 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, and L is a direct bond or a divalent linking group M is an integer from 1 to 4, n is 4-m.

The total amount of the silane compound and the chromic acid compound may include 10 to 80 parts by weight of the silane compound and 20 to 90 parts by weight of the chromic acid compound.

In formula 1 R ¹ can be hydrogen, a halogen atom, a straight-chain or branched alkyl group or alkoxy group.

In Formula 1, L may be at least one of a direct bond, an alkylene group, and —CF ₂ —.

The silane compound may be represented by the following formula (2).

[Formula 2]

R ¹ to R ³ in Formula 2 are each independently hydrogen, a halogen element, a straight 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, and L ₁ Is a direct bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

R ² and R ³ in Formula 2 may each independently be a hydrogen or a halogen element.

The silane compounds are triethyl (trifluoromethyl) silane (triethyl), trimethoxy (trifluoropropyl) silane (trimethoxypropyl) silane, Dimethoxy-methyl (trifluoropropyl) silane (dimethoxy-methyl) (Trifluopropyl) silane) and Perfluorooctyl-triethoxysilane (perfluorooctyl-triethoxysilane).

The total amount of the silane compound and the chromic acid compound may further include 0.5 to 65 parts by weight of the ceramic powder.

Ceramic powder is _{MgO, MnO, Al 2 O 3} , SiO 2, TiO 2, Zr0 2, Al 6 Si 2 O 13, Al 2 O 3 · TiO 2, Y 2 O 3, 9Al 2 O 3 · B 2 O 3 , BN, CrN, BaTiO ₃ , SiC, and TiC.

The average particle diameter of the ceramic powder may be 0.05 to 20 μm.

Acrylic resin, styrene resin, vinyl acetate resin, polyester resin, urethane resin, polyethylene resin, polypropylene resin, polyamide resin, polycarbonate resin, phenol resin, alkyd resin, based on 100 parts by weight of the silane compound and the chromic acid compound. And 0.5 to 30 parts by weight of one or more polymer resins in the epoxy resin.

1 to 15 parts by weight of one or more of ethylene glycol, propylene glycol, glycerine, and butyl carbitol based on 100 parts by weight of the silane compound and the chromic acid compound It may include.

An electrical steel sheet according to an embodiment of the present invention includes an electrical steel sheet substrate and an insulating film located on one or both sides of the electrical steel sheet substrate.

The insulating film is a silane compound represented by the following formula (1); And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, a straight 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, and L is a direct bond or a divalent linking group M is an integer from 1 to 4, n is 4-m.

The insulating film contains 0.1 to 50% by weight of Si and 0.01 to 25% by weight of F.

The thickness of the insulating coating may be 0.1 to 10㎛.

Method for producing an electrical steel sheet according to an embodiment of the present invention comprises the steps of preparing an electrical steel sheet; And forming an insulating coating by applying the insulating coating composition to one or both surfaces of the electrical steel sheet substrate.

The insulation coating composition may include an silane compound represented by Formula 1 below; And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, a straight 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, and L is a direct bond or a divalent linking group M is an integer from 1 to 4, n is 4-m.

The manufacturing of the electrical steel sheet may include hot rolling the slab to prepare a hot rolled sheet; Cold rolling of the hot rolled sheet may include producing a cold rolled sheet and the final annealing of the cold rolled sheet.

The forming of the insulating film may include heat treating the steel sheet to which the insulating film composition is applied at a temperature of 100 to 680 ° C.

After forming the insulating film, it may further include the step of stress relief annealing at a temperature of 700 to 1000 ℃.

According to one embodiment of the present invention, it is possible to obtain an electrical steel sheet having excellent iron loss characteristics after the insulation film is formed.

According to one embodiment of the present invention, it is possible to obtain an electrical steel sheet having excellent spot ratio.

According to one embodiment of the present invention, an insulating film having excellent adhesion and peeling resistance can be obtained even after stress relief annealing (SRA).

According to one embodiment of the present invention, it is possible to manufacture an electrical steel sheet having excellent thermal conductivity, and products such as a motor manufactured using the electrical steel sheet are excellent in efficiency.

1 is a schematic diagram of a cross section of an electrical steel sheet according to an embodiment of the present invention.

2 is a flowchart of a method of manufacturing an electrical steel sheet according to an embodiment of the present invention.

3 is a scanning electron microscope (SEM) photograph of the cross section of the electrical steel sheet prepared in Example 1-2.

4 is a scanning electron microscope (SEM) photograph of the cross section of the electrical steel sheet prepared in Comparative Example 1-2.

5 is a result of the FT-IR-RAS analysis of the electrical steel film prepared in Example 1-2.

6 is a scanning electron microscope (SEM) photograph of the cross section of the electrical steel sheet prepared in Example 2-2.

7 is a scanning electron microscope (SEM) photograph of the surface of the electrical steel sheet prepared in Comparative Example 2-3.

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

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular property, region, integer, step, operation, element, and / or component, and the presence of another property, region, integer, step, operation, element, and / or component, or It does not exclude the addition.

When a portion is referred to as being "on" or "on" another portion, it may be directly on or on the other portion or may be accompanied by another portion therebetween. In contrast, when a part is mentioned as "directly above" another part, no other part is intervened in between.

Although not defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted as ideal or very formal meaning unless defined.

In the description of group (atom group) in this specification, the description which is not describing substitution and unsubstitution includes what has a substituent with the thing which does not have a substituent. For example, an "alkyl group" includes not only the alkyl group (unsubstituted alkyl group) which does not have a substituent but the alkyl group (substituted alkyl group) which has a substituent.

As used herein, unless otherwise defined, at least one hydrogen in the compound 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; Alkoxysilane groups; Amine groups; Alkylamine group; Arylamine group; Mean substituted by ethyleneoxyl group or halogen group.

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

As used herein, unless otherwise defined, an "alkyl group" means a "saturated alkyl group" that does not include any alkenyl or alkynyl groups; Or "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 "alkyn 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 an alkyl group of C1 to C20, specifically, a lower alkyl group of C1 to C6, a middle alkyl group of C7 to C10, and a higher alkyl group of C11 to C20.

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 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 and cyclo Pentyl group, cyclohexyl group, and the like.

"Aromatic group" means a substituent in which all elements of the 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 fused ring, ie, a plurality of ring substituents that divide adjacent pairs of carbon atoms.

"Heteroaryl group" means an aryl group containing a hetero atom 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 include 1 to 3 heteroatoms.

Unless defined otherwise in the specification, 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, It means an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group.

Unless otherwise defined herein, a divalent linking group is 1 selected from an alkylene group, an alkenylene group, an arylene group, -NR'-, -O-, -SO _2- , -CO-, and -CF _2- It means two or more divalent linking groups. R 'is an alkyl group.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Insulation coating composition for electrical steel sheet

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a silane compound represented by the formula (1) and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

Insulating coating composition according to an embodiment of the present invention includes a silane compound having a unique chemical structure to significantly improve the stress relief annealing heat resistance and corrosion resistance. In addition, when the silane compound is used alone, there is a problem in that the film is peeled off during the stress relief annealing process and difficulty in uniformly applying the surface of the electrical steel sheet. Metal hydroxides are also included to improve this.

Hereinafter, the insulating film composition for electrical steel sheet according to an embodiment of the present invention will be described in detail for each component.

First, the insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a silane compound represented by Formula 1 on a solids basis. Specifically, the total amount of the silane compound and the metal hydroxide may include 30 to 75 parts by weight.

The silane compound represented by the formula (1) contains Si element and carbonyl group (Carbonyl group) in the compound and is excellent in heat resistance. In addition, the carbonyl group has an excellent reactivity with the metal hydroxide to play an important role in forming the silane compound-metal hydroxide complex and significantly improving the surface quality.

Specifically, the silane compound may be represented by the following formula (2).

[Formula 2]

(In Formula 2, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cyclo alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L ¹ is directly A bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

Specifically, in Formula 1 and Formula 2, R ¹ and R ² may be hydrogen or an alkyl group. More specifically, R ¹ and R ² may be a methyl group or an ethyl group.

Specifically, in Formula 1, L may be one or more divalent linking groups selected from alkylene groups, -O-, and -CO-. More specifically, in Formula 1, L may be represented by -L ¹ -O-, L ¹ may be a direct bond or at least one divalent linking group selected from an alkylene group, -O-, and -CO-.

Silane compounds include triacetoxy (methyl) silane, triacetoxy (vinyl) silane, dimethyldimethacroyloxy-1-ethoxysilane (Dimethyl-di (methacroyloxy-1-) ethoxy) silane) and 3- (trimethoxysilyl) propylmethacrylate (3- (trimethoxysilyl) propylmethacrylate).

If too little silane compound is included, the heat resistance may deteriorate and the iron loss may be lost after stress relief annealing. If too much silane compound is included, the amount of metal hydroxide is relatively low, and the coating may be peeled off. Therefore, the silane compound may be included in the aforementioned range. More specifically, the silane compound may include 40 to 55 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention comprises a metal hydroxide. Specifically, the amount of the metal hydroxide is 25 to 70 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

Metal hydroxides are well dispersed in solvents and help to change the surface properties from hydrophobic to hydrophilic so that they can be well dispersed in solvents through chemical reactions with functional groups of silane compounds. Since the metal hydroxide is uniformly applied to the surface of the electrical steel sheet, it is a great help to significantly improve the heat resistance and corrosion resistance during stress relief annealing of the insulating film.

The metal hydroxide can be used without limitation so long as it is a metal containing a hydroxyl group (—OH). Specifically, the metal hydroxides are Ni (OH) ₂ , Co (OH) ₂ , Cu (OH) ₂ , Sr (OH) ₂ , Ba (OH) ₂ , Pd (OH) ₂ , In (OH) ₃ , (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ , Bi (OH) ₃ And Sn (OH) ₂ It may include one or more. More specifically, it may include one or more of Co (OH) ₂ and (CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ .

If too little metal hydroxide is included, problems may occur in the dispersion of the silane compound, making it difficult to apply uniformly. When too much metal hydroxide is included, the silane compound may be relatively small, so that the improvement of heat resistance and corrosion resistance during stress relief annealing may be insufficient. More specifically, the total amount of the silane compound and the metal hydroxide may include 45 to 60 parts by weight of the metal hydroxide.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention may further include a metal nitride in addition to the silane compound and the metal hydroxide. In the case of further including an appropriate amount of the metal nitride, the insulating properties and the thermal conductivity of the insulating film to be formed can be further improved.

When the metal nitride is further included, the solid content may include 0.1 to 40 wt% of the metal nitride, 25 to 75 wt% of the silane compound, and 0.5 to 60 wt% of the metal hydroxide.

Solid content means the thing based on 100 weight% of solid parts except volatile components, such as a solvent in an insulation coating composition.

If too little metal nitride is added, the effect of improving the insulating properties and the thermal conductivity properties may be insufficient. If too much metal nitride is included, the amount of the silane compound and the metal hydroxide may be relatively low, resulting in insufficient heat and corrosion resistance improvement during stress relief annealing. More specifically, the solid content may include 1 to 25 wt% of metal nitride, 35 to 65 wt% of silane compound, and 15 to 50 wt% of metal hydroxide.

The metal nitride may include at least one of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .

The average particle diameter of the metal nitride may be 0.05 to 20 μm. The particle size of the metal nitride should be appropriate, so that dispersibility and applicability are easy.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention is one or more of ethylene compounds and metal nitrides of ethylene glycol (Ethylene golycol), propylene glycol (Propylene glycol), glycerin (Glycerine), butyl carbitol (Butyl carbitol) It may further include. By further including the above-mentioned additives, it is possible to form an insulating film having excellent surface gloss and very beautiful roughness. The above-mentioned additives may be further included in an amount of 1 to 15 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide. If too little additive is included, the above-mentioned improvement effect may be insufficient. Even if the additive is further included, there is no further improving effect, but may be inferior in dispersibility. More specifically, the additive may be included in an amount of 3 to 10 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide.

The insulating coating composition may further include a solvent for even dispersion and easy application of the solids. Water, alcohol, or the like may be used as the solvent, and may include 300 to 1000 parts by weight based on 100 parts by weight of the total amount of the silane compound and the metal hydroxide. As such, the insulating coating composition may be in the form of a slurry.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention is a silane compound represented by the formula (1) silane compound; And at least one chromic acid compound selected from chromic anhydride, chromate and dichromate.

[Formula 1]

In Formula 1, R ¹ is hydrogen, a halogen element, a straight 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, and L is a direct bond or a divalent linking group M is an integer from 1 to 4, n is 4-m.

Insulating coating composition according to an embodiment of the present invention includes a silane compound having a unique chemical structure to significantly improve the stress relief annealing heat resistance and corrosion resistance. In addition, when the silane compound is used alone, there is a problem in that the film is peeled off during the stress relief annealing process and difficulty in uniformly applying the surface of the electrical steel sheet. It also includes chromic acid compounds to improve this.

Hereinafter, the insulating film composition for electrical steel sheet according to an embodiment of the present invention will be described in detail for each component.

First, the insulating coating composition for an electrical steel sheet according to an embodiment of the present invention includes a silane compound represented by Chemical Formula 1.

The silane compound represented by the formula (1) contains Si element and F element in the compound and is extremely excellent in heat resistance. In particular, the element F has an effect of suppressing a chemical reaction in which moisture in the air penetrates into the insulating film, and thus plays an important role in remarkably improving the surface quality of electrical steel sheet due to its excellent chemical resistance, insulation, and corrosion resistance.

The total amount of the silane compound and the chromic acid compound may include 10 to 80 parts by weight of the silane compound.

If too little silane compound is included, the content of Si and F elements in the insulating film to be formed decreases heat resistance, which may lead to heat loss after stress relief annealing. The compatibility with the solvent may be lowered, which may cause a problem of difficulty in forming a uniform insulating film. Therefore, the silane compound may be included in the aforementioned range. More specifically, the silane compound may be included from 40 to 70 parts by weight.

In formula 1 R ¹ can be hydrogen, a halogen atom, a straight-chain or branched alkyl group or alkoxy group. When m is 2 or more, a plurality of R ¹ may be the same or different from each other.

In Formula 1, L may be at least one of a direct bond, an alkylene group, and —CF ₂ —. When n is 2 or more, the plurality of L's may be the same or different from each other.

Specifically, the silane compound may be represented by the following formula (2).

[Formula 2]

R ¹ to R ³ in Formula 2 are each independently hydrogen, a halogen element, a straight 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, and L ₁ Is a direct bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

Specifically, in Formula 2, R ¹ , m, n are the same as the description of Formula 1.

L ₁ may be a direct bond or a divalent linking group. More specifically, L ₁ may be at least _one of a direct bond, an alkylene group, and —CF ₂ —.

R ² and R ³ may be each independently hydrogen or a halogen element.

The silane compounds are triethyl (trifluoromethyl) silane (triethyl), trimethoxy (trifluoropropyl) silane (trimethoxy) silane, Dimethoxy-methyl (trifluoropropyl) silane (dimethoxy-methyl) (Tripulofluoropropyl) silane) and Perfluorooctyl-triethoxysilane (perfluorooctyl-triethoxysilane).

More specifically, the silane compounds are triethyl (trifluoromethyl) silane, Trimethoxy (3,3,3-trifluoropropyl) silane, Dimethoxy-methyl (3,3,3-trifluoropropyl) silane and 1H, 1H, 2H, 2H-Perfluorooctyl-triethoxysilane It may include one or more of.

The insulating coating composition for electrical steel sheet according to one embodiment of the present invention includes at least one chromic acid compound selected from chromic anhydride, chromate and dichromate.

The chromic acid compound chemically reacts with the silane compound to improve dispersion stability to form a uniform film. In addition, the chromic acid compound has the advantage of reducing the cost in mass production and has the advantage that can be stably operated in the insulation coating process.

As chromate and dichromate, salts, such as Na, K, Mg, Ca, Mn, Mo, Zn, Al, can be used, for example.

The total amount of the silane compound and the chromic acid compound may include 20 to 90 parts by weight of the chromic acid compound. If too little chromic acid compound is included, problems may occur in dispersion of the silane compound, making it difficult to uniformly apply the chromic acid compound. When too much chromic acid compound is included, the silane compound may be relatively small, and thus the improvement of heat resistance and corrosion resistance during stress relief annealing may be insufficient. More specifically, the chromic acid compound may be included in 30 to 60 parts by weight.

Insulating coating composition for an electrical steel sheet according to an embodiment of the present invention may further include a ceramic powder in addition to the silane compound and chromic acid compound. When the ceramic powder is further included in an appropriate amount, the insulating properties of the insulating film to be formed may be further improved.

The ceramic powder may be included in an amount of 0.5 to 65 parts by weight based on 100 parts by weight of the silane compound and the chromic acid compound. If too little ceramic powder is included, the effect of improving the insulating properties may be insufficient. If too much ceramic powder is included, the amount of the silane compound and the chromic acid compound may be relatively low, resulting in insufficient heat and corrosion resistance improvement during stress relief annealing. More specifically, the ceramic powder may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the silane compound and the chromic acid compound.

Ceramic powder is _{MgO, MnO, Al 2 O 3} , SiO 2, TiO 2, ZrO 2, Al 6 Si 2 O 13, Al 2 O 3 · TiO 2, Y 2 O 3, 9Al 2 O 3 · B 2 O 3 , BN, CrN, BaTiO ₃ , SiC, and TiC. More specifically, the ceramic powder is MgO, CaO, Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ · TiO ₂ , Y ₂ O ₃ , 9Al ₂ O ₃ · B ₂ O ₃ , BN, May contain one or more of CrN, BaTiO ₃ , SiC, and TiC

The average particle diameter of the ceramic powder may be 0.05 to 20 μm. The particle diameter of the ceramic powder should be appropriate, so that dispersibility and applicability are easy.

Insulating coating composition for electrical steel sheet according to an embodiment of the present invention is based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound, acrylic resin, styrene resin, vinyl acetate resin, polyester resin, urethane resin, polyethylene resin, polypropylene resin It may further comprise 0.5 to 30 parts by weight of at least one polymer resin of polyamide resin, polycarbonate resin, phenol resin, alkyd resin and epoxy resin. By adding an appropriate amount of the above-mentioned polymer resin further, it is possible to produce an electrical steel sheet excellent in surface gloss and very beautiful roughness.

Insulating coating composition for electrical steel sheet according to an embodiment of the present invention is based on 100 parts by weight of the silane compound and chromic acid compound, ethylene glycol (Ethylene golycol), propylene glycol (Glycerine), glycerine (butyl carbitol) Butyl carbitol) may further comprise 1 to 15 parts by weight of one or more. By further including the above-mentioned additives, it is possible to form an insulating film having excellent surface gloss and very beautiful roughness. If too little additive is included, the above-mentioned improvement effect may be insufficient. Even if the additive is further included, there is no further improving effect, but may be inferior in dispersibility. More specifically, the additive may be included in an amount of 3 to 10 parts by weight based on 100 parts by weight of the silane compound and the chromic acid compound.

The insulating coating composition may further include a solvent for even dispersion and easy application of the solids. Water, alcohol, or the like may be used as the solvent, and may include 300 to 1000 parts by weight based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound. As such, the insulating coating composition may be in the form of a slurry.

Electrical steel sheet

The electrical steel sheet 100 according to the embodiment of the present invention includes an electrical steel sheet substrate 10 and an insulating coating 20 located on one or both surfaces of the electrical steel sheet substrate 10. 1 is a schematic side cross-sectional view of an electrical steel sheet according to an embodiment of the present invention. In FIG. 1, the insulating film 20 is formed on the upper surface of the electrical steel sheet substrate 10.

The insulating film 20 includes a silane compound represented by the following formula (1) and a metal hydroxide.

[Formula 1]

(In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)

Insulating coating 20 of electrical steel sheet 100 according to an embodiment of the present invention includes a silane compound having a unique chemical structure to significantly improve the stress relief annealing heat resistance and corrosion resistance and also improve the thermal conductivity. In addition, when the silane compound is used alone, there is a problem in that the film is peeled off during the stress relief annealing process and difficulty in uniformly applying the surface of the electrical steel sheet. Metal hydroxides are also included to improve this.

Since the content of the components of the insulating film 20 has been described in detail with respect to the above-described insulating film composition, redundant descriptions thereof will be omitted. While the chemical structure of some silane compounds may be modified during the formation of the insulating film 20, most of the silane compounds retain their chemical structure. In addition, the silane compound and the metal hydroxide may react to form a compound in the process of forming the insulating film 20. In this case, the ratio of the silane compound and the metal hydroxide content in the compound may be calculated to calculate the silane compound and the metal hydroxide, respectively. Calculate by weight. Since volatile components, such as a solvent, are removed in the formation process of the insulating film 20, the component in the insulating film 20 is substantially the same as the solid content component in an insulating film composition.

The insulating film 20 may include 0.1 to 50 wt% of Si. In this case, Si may be Si in the silane compound, Si in the metal nitride, or Si diffused from the electrical steel sheet substrate 10 when Si ₃ N ₄ is used as the metal nitride. An appropriate amount of Si is included to ensure the insulating properties of the insulating film 20.

The insulating film 20 may include, in addition to Si, an element derived from the insulating film composition such as Fe, C, O and the electrical steel sheet substrate 10.

The thickness of the insulating film 20 may be 0.1 to 10㎛. If the thickness of the insulating film 20 is too thin, the heat resistance is lowered, there may be a problem that the iron loss is heated after the stress relief annealing. If the thickness of the insulating film 20 is too thick, the spot ratio may be lowered, which may cause a problem of inferior motor characteristics. Therefore, the thickness of the insulating film 20 can be adjusted to the above-mentioned range. More specifically, the thickness of the insulating film 20 may be 0.2 to 5 ㎛.

The electrical steel substrate 10 may be used without limitation for non-oriented electrical steel sheets or oriented electrical steel sheets. Specifically, non-oriented electrical steel sheet can be used. In one embodiment of the present invention, the insulating property is generated by the component of the insulating film 20, and may be independent of the alloy component of the electrical steel sheet. Hereinafter, as an example, the alloy component of the electrical steel sheet will be described.

Electrical steel sheet is C: 0.01% by weight or less, Si: 6.0% by weight or less, P: 0.5% by weight or less, S: 0.005% by weight or less, Mn: 0.1 to 1.0% by weight, Al: 0.40 to 2.0% by weight, N: 0.005 Up to% by weight, up to 0.005% by weight of Ti and Sb, Sn, Ni or a combination thereof: from 0.01 to 0.15% by weight, and may include Fe and unavoidable impurities in the balance.

Hereinafter, each alloy component will be described in detail.

Hereinafter, the reason for limitation of the non-oriented electrical steel sheet base material 10 component is demonstrated.

C: 0.01 wt% or less

Carbon (C) in the embodiment according to the present invention is a component that does not greatly help to improve the magnetic properties of the electrical steel sheet is preferably removed as possible. C may be contained in an amount of 0.01% by weight or less since it causes magnetic aging in the final product and lowers its magnetic properties during use.The lower the content of C, the better the magnetic property, so it is more preferable to limit it to 0.005% by weight or less in the final product. Do.

Si: 6.0 wt% or less

Silicon (Si) is a component that reduces the eddy current loss during iron loss by increasing the specific resistance of the steel, if the content of Si is too large, the brittleness may increase, which makes it difficult to cold rolling. Therefore, it is desirable to limit to 6.0% by weight or less. More specifically Si may be included 0.1 to 4.0% by weight.

P: 0.5 weight% or less

Phosphorus (P) is added to increase the resistivity, improve the texture and improve the magnetism. If excessively added, the cold rolling property is deteriorated, so it is preferable to limit it to 0.5% by weight or less.

S: 0.005 wt% or less

Sulfur (S) is to be managed as low as possible because it forms a fine precipitates MnS and CuS and inhibits grain growth to deteriorate the magnetic properties, so the content is limited to 0.005% by weight or less.

Mn: 0.1-1.0 wt%

When manganese (Mn) is present in less than 0.1% by weight, fine MnS precipitates are formed, which inhibits grain growth, thereby deteriorating magnetism. Therefore, when 0.1 weight% or more exists, coarse MnS is formed and S component can be prevented from being precipitated by CuS which is a finer precipitate. However, when Mn increases, since magnetic deteriorates, it adds at 1.0 weight% or less.

Al: 0.40 to 2.0 wt%

Al is an effective component to lower the eddy current loss by increasing the specific resistance. In the case of less than 0.40% by weight, AlN is finely precipitated and inferior in magnetism, and when it exceeds 2.0% by weight, the workability is deteriorated, so it is preferable to limit it to 2.0% by weight or less.

N: 0.005 wt% or less

Since N forms fine and long AlN precipitates inside the base material and suppresses grain growth, the content of N is preferably less than 0.005% by weight.

Ti: 0.005 wt% or less

Ti inhibits grain growth by forming fine precipitates of TiN and TiC, and when added in excess of 0.005% by weight, many fine precipitates occur to worsen the texture and deteriorate the magnetic properties.

Sb, Sn, Ni or a combination thereof: 0.01 to 0.15 wt%

Sb, Sn, or Ni is a surface precipitation element, which concentrates on the surface layer of the steel sheet to suppress the adsorption of nitrogen, and consequently serves to lower iron loss by not inhibiting the growth of crystal grains. Too low a content can cause a problem of poor effect. If the content of Sb, Sn, or Ni alone or in combination is too high, grain boundary segregation may occur severely, leading to brittleness of the steel sheet, which may cause plate breakage during rolling. When two or more kinds of Sb, Sn, and Ni are added in combination, the total amount thereof may be 0.01 to 0.15 wt%.

More specifically, it may include 0.01 to 0.05% by weight of Sb, 0.01 to 0.12% by weight of Sn, and 0.01 to 0.06% by weight of Ni.

As described above, the electrical steel sheet according to the embodiment of the present invention has excellent thermal conductivity due to the formation of an insulating film. Specifically, the following general formula (1) can be satisfied.

[Formula 1]

20≤ TC ≤ 200 W / mK

(In Formula 1, TC represents a thermal conductivity value measured by PPMS (Physical Property Measurement System) after induction heating of a specimen of 600x400mm 230 ℃.)

Insulating coating 20 of the electrical steel sheet 100 according to an embodiment of the present invention includes a silane compound having a unique chemical structure to significantly improve the stress relief annealing heat resistance and corrosion resistance. In addition, when the silane compound is used alone, there is a problem in that the film is peeled off during the stress relief annealing process and difficulty in uniformly applying the surface of the electrical steel sheet. It also includes chromic acid compounds to improve this.

Since the content of the components of the insulating film 20 has been described in detail with respect to the above-described insulating film composition, redundant descriptions thereof will be omitted. While the chemical structure of some silane compounds may be modified during the formation of the insulating film 20, most of the silane compounds retain their chemical structure. In addition, the silane compound and the chromic acid compound may react to form a compound in the process of forming the insulating film 20. In this case, the silane compound and the chromic acid compound may be calculated by calculating the ratio of the silane compound and the chromic acid compound in the compound, respectively. Calculate by weight. Since volatile components, such as a solvent, are removed in the formation process of the insulating film 20, the component in the insulating film 20 is substantially the same as the solid content component in an insulating film composition. Solid content means the thing based on 100 weight% of solid parts except volatile components, such as a solvent in an insulation coating composition.

The insulating film 20 may include 0.1 to 50% by weight of Si and 0.01 to 25% by weight of F. In this case, Si may be Si in the silane compound, Si in the ceramic powder, or Si diffused from the electrical steel sheet substrate 10 when SiO ₂ is used as the ceramic powder. An appropriate amount of Si is included to ensure the insulating properties of the insulating film 20.

F may also be derived from F in the silane compound. An appropriate amount of F can be included to improve chemical resistance, insulation, and corrosion resistance of the insulating coating 20.

The insulating film 20 may include elements derived from the insulating film composition such as Cr, Fe, C, O and the electrical steel sheet substrate 10 in addition to Si and F.

The thickness of the insulating film 20 may be 0.1 to 10㎛. If the thickness of the insulating film 20 is too thin, the heat resistance is lowered, there may be a problem that the iron loss is heated after the stress relief annealing. If the thickness of the insulating film 20 is too thick, the spot ratio may be lowered, which may cause a problem of inferior motor characteristics. Therefore, the thickness of the insulating film 20 can be adjusted to the above-mentioned range. More specifically, the thickness of the insulating film 20 may be 0.2 to 5 ㎛.

Manufacturing method of electrical steel

Figure 2 schematically shows a flow chart of the manufacturing method of the electrical steel sheet according to an embodiment of the present invention. The flowchart of the manufacturing method of the electrical steel sheet of FIG. 2 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the manufacturing method of the electrical steel sheet can be variously modified.

As shown in Figure 2, the manufacturing method of the electrical steel sheet comprises the steps of preparing the electrical steel sheet (S10); And applying an insulating coating composition to one or both surfaces of the electrical steel sheet to form an insulating coating (S20). In addition, the manufacturing method of the electrical steel sheet may further include other steps.

First, in step S10 to prepare an electrical steel sheet substrate. Since the alloy component of the electrical steel sheet substrate has been described in detail, repeated descriptions are omitted.

The manufacturing of the electrical steel sheet may include hot rolling the slab to prepare a hot rolled sheet; Cold rolling of the hot rolled sheet may include producing a cold rolled sheet and the final annealing of the cold rolled sheet.

First, the slab is heated. At this time, the slab heating may be heated at 1,200 ℃ or less.

Next, the heated slab is hot rolled to produce a hot rolled sheet. The produced hot rolled sheet can be hot rolled annealed.

Next, the hot rolled sheet is cold rolled to produce a cold rolled sheet. Cold rolling may be performed once, or two or more cold rolling including intermediate annealing may be performed.

Next, the cold rolled sheet is finally annealed. In this case, in the final annealing of the cold rolled sheet, the rolling oil present in the cold rolled sheet may be degreased and subjected to the first annealing, and the second annealing may be performed in an atmosphere composed of hydrogen and nitrogen. In addition, the final annealing can control the dew point temperature to -5 ℃ or less for the purpose of preventing the formation of oxide on the surface of the magnetic deterioration.

Returning to the description of the manufacturing method of the electrical steel sheet, the next step (S20) to form an insulating coating by applying an insulating coating composition on one side or both sides of the electrical steel substrate. Since the insulation coating composition is the same as that described above, overlapping descriptions are omitted.

The forming of the insulating film may include heat treating the steel sheet to which the insulating coating composition is applied at a temperature of 100 to 680 ° C. If the heat treatment temperature is too low, the removal of the solvent is not easy, and a beautiful insulating film is hardly formed. Too high a heat treatment temperature may cause a problem of inferior adhesion. More specifically, the heat treatment may be performed at a temperature of 350 to 650 ° C. The heat treatment time may be 5 to 200 seconds.

After forming the insulating film, it may further include the step of stress relief annealing at a temperature of 700 to 1000 ℃. In one embodiment of the present invention, the adhesion and surface properties of the insulating film can be excellently maintained even after stress relief annealing by the silane compound and the metal hydroxide in the insulating film composition. If the temperature of the stress relief annealing is too low, the desired stress relief may not be performed smoothly. If the temperature of the stress relief annealing is too high, the magnetism of the electrical steel sheet may be inferior.

The stress relief annealing step may be performed in a nitrogen atmosphere, and may be performed for 1 to 5 hours.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are only for illustrating the present invention, and the present invention is not limited thereto.

Experimental Example 1-1: Characteristics of Types of Silane Compounds

Example 1-1

3.4% by weight of silicon (Si), aluminum (Al): 0.80% by weight, manganese (Mn): 0.17% by weight titanium (Ti): 0.0015% by weight, tin (Sn): 0.03% by weight, nickel (Ni): 0.01 % By weight, carbon (C): 0.003% by weight, nitrogen (N): 0.0013% by weight, phosphorus (P): 0.012% by weight, sulfur (S): 0.001% by weight, and the balance consists of Fe and other unavoidable impurities Slabs were prepared.

The slab was heated at 1130 ° C. and hot rolled to a thickness of 2.3 mm to prepare a hot rolled sheet.

The hot rolled sheet was wound at 650 ° C., cooled in air, subjected to hot rolled sheet annealing at 1040 ° C. for 2 minutes, quenched in water, pickled, and cold rolled to a thickness of 0.35 mm to prepare a cold rolled sheet.

The cold rolled sheet was annealed at 1040 ° C. for 50 seconds in an atmosphere of 20% hydrogen and 80% nitrogen, and then subjected to final annealing to prepare an annealed steel sheet.

As the insulating coating composition, 60 parts by weight of triacetoxymethylsilane, 20 parts by weight of nickel hydroxide (Ni (OH) ₂ ), 10 parts by weight of strontium hydroxide (Sr (OH) ₂ ), 5 parts by weight of boron nitride, and 5 parts by weight of ethylene glycol The mixture was mixed with distilled water to prepare a slurry. The slurry was applied to the final annealed steel sheet using a roll, and then heat-treated at 650 ° C. for 30 seconds and cooled in air. The electrical steel sheet was subjected to Stress Relief Annealing (SRA) at 100% nitrogen atmosphere at 750 ° C. for 2 hours, and cooled in air. The thickness of the insulating film was about 0.8 mu m.

Examples 1-2 to 1-12

In the same manner as in Example 1-1, the amount and type of the silane compound, the metal hydroxide, and the metal nitride in the insulating coating composition were changed as shown in Table 1 to form an insulating coating.

Comparative Example 1-1

In the same manner as in Example 1-1, without using a metal hydroxide, an insulating coating composition containing 100 parts by weight of triacetoxymethylsilane was used.

Comparative Example 1-2

In the same manner as in Example 1-1, without using a silane compound, an insulating coating composition containing 100 parts by weight of chromium hydroxide was used.

Comparative Example 1-3

In the same manner as in Example 1-1, without using a silane compound, an insulating coating composition including 60 parts by weight of chromium hydroxide and 40 parts by weight of boron nitride was used.

The properties of the electrical steel sheets prepared in Examples and Comparative Examples were summarized in Table 2 below.

_Iron loss (W _15/50 ) refers to the power loss that occurs when a magnetic field with a frequency of 50 Hz is magnetized by alternating current to 1.5 Tesla.

In addition, the insulation properties were measured by using a Franklin meter in accordance with the ASTM A717 International Standard.

In addition, the adhesion is shown by the minimum arc diameter without film peeling when the specimen is bent 180 ° in contact with a 10 to 100 mm arc.

In addition, the surface characteristic is a result of visually evaluating the degree to which a uniform film is formed and a uniform color.

In addition, the thermal conductivity of the electrical steel sheet was induction heating 230 ℃ and the thermal conductivity of the specimen was measured by PPMS (Physical property measurement system, manufactured by Quantum Design).

As shown in Table 1 and Table 2, it can be confirmed that the insulating film characteristic of the Example is superior to the comparative example. In addition, when the silane compound or the metal hydroxide is included alone, peeling of the film occurs excessively, and it can be confirmed that the magnetic properties are deteriorated.

3 and 4 show a scanning electron microscope (SEM) photograph of the cross section of the electrical steel sheet prepared in Example 1-2 and Comparative Example 1-2, respectively. As shown in Figure 3, in the case of Example 1-2, it can be seen that the beautiful insulating film is maintained even after the SRA. On the other hand, as shown in Figure 4, in Comparative Example 1-2, after the SRA, it can be seen that a large number of cracks on the surface of the insulating film.

Figure 5 shows the results of the FT-IR-RAS analysis of the electrical steel film prepared in Example 1-2. As can be seen in Figure 5, it can be seen that the triacetoxy vinylsilane is present in the film.

Experimental Example 1-2: Droplet Rate Evaluation

Example 1-13

4.2 wt% of silicon (Si), 0.80 wt% of aluminum (Al), 0.15 wt% of manganese (Mn), 0.001 wt% of titanium (Ti), 0.08 wt% of tin (Sn), and 0.004 of carbon (C) Wt%, nitrogen (N) 0.0015% by weight, phosphorus (P) 0.015% by weight, sulfur (S) 0.001% by weight, the balance was prepared a slab consisting of Fe and other unavoidable impurities.

The slab was heated at 1150 ° C. and then hot rolled to a thickness of 2.3 mm to prepare a hot rolled plate.

The hot rolled sheet was wound at 650 ° C., cooled in air, subjected to hot rolled sheet annealing at 1040 ° C. for 3 minutes, quenched in water, pickled, and cold rolled to a thickness of 0.35 mm to prepare a cold rolled sheet.

The cold rolled sheet was adjusted to a dew point temperature of −40 ° C. in a 30% hydrogen and 70% nitrogen atmosphere at 1050 ° C. for 60 seconds, and final annealing was performed to prepare an annealed steel sheet.

Then, 25 parts by weight of triacetoxymethylsilane, 25 parts by weight of triacetoxy vinylsilane, 15 parts by weight of chromium hydroxide ((CH ₃ CO ₂ ) ₇ Cr ₃ (OH) ₂ ) as the insulating coating composition, cobalt hydroxide (Co (OH) ₂ ) 15 parts by weight, strontium hydroxide (Sr (OH) ₂ ) 3 parts by weight, boron nitride 15 parts by weight and propylene glycol 2 parts by mixing with distilled water to prepare a slurry, the thickness of the slurry using a roll After the coating, the substrate was heat-treated at 650 ° C. for 30 seconds and cooled in air. The steel sheet was subjected to Stress Relief Annealing (SRA) heat treatment at 100% nitrogen atmosphere at 820 ° C. for 2 hours, and cooled in air. The stress relief annealed steel sheet was treated for 24 hours at 60 ° C. and 95% humidity for 24 hours.

Comparative Example 1-5

About 7 parts by weight of MgO and CaO were slowly added to the ionized water, and then about 20 parts by weight of CrO ₃ , which caused an exothermic reaction, was slowly injected into the solution (MgO, CaO + ionized water) and stirred and branded until a clear brown liquid was obtained. .

Thereafter, about 30 parts by weight of one kind of acrylic resin or acrylic-styrene copolymer resin and 6.7 parts by weight of butyl carbitol as a reducing agent were injected into the solution to prepare an insulating coating composition.

In the same manner as in Example 1-13, using the prepared insulation coating composition to form an insulation coating.

Comparative Example 1-6

50 parts by weight of monobasic aluminum phosphate (Al (H ₂ PO ₄ ) ₃ ), 50 parts by weight of zinc monophosphate (Zn (H ₂ PO ₄ ) ₂ ), 210 parts by weight of epoxy resin, cobalt hydroxide The insulating coating composition containing 1 weight part, 1 weight part of strontium hydroxide, and 0.05 weight part of Ti chelating agents was used.

In the same manner as in Example 1-13, but using the insulating film composition to form an insulating film.

As shown in Table 3, it can be seen that the properties of Example 1-13 are significantly superior to Comparative Examples 1-5 and 1-6.

Experimental Example 2-1: Characteristics by Type of Silane Compound

Example 2-1

3.4% by weight of silicon (Si), aluminum (Al): 0.80% by weight, manganese (Mn): 0.17% by weight titanium (Ti): 0.0015% by weight, tin (Sn): 0.03% by weight, bismuth (Bi): 0.01 % By weight, carbon (C): 0.003% by weight, nitrogen (N): 0.0013% by weight, phosphorus (P): 0.012% by weight, sulfur (S): 0.001% by weight, and the balance consists of Fe and other unavoidable impurities Slabs were prepared.

The slab was heated at 1130 ° C. and hot rolled to a thickness of 2.3 mm to prepare a hot rolled sheet.

The hot rolled sheet was wound at 650 ° C., cooled in air, subjected to hot rolled sheet annealing at 1040 ° C. for 2 minutes, quenched in water, pickled, and cold rolled to a thickness of 0.35 mm to prepare a cold rolled sheet.

The cold rolled sheet was annealed at 1040 ° C. for 50 seconds in an atmosphere of 20% hydrogen and 80% nitrogen, and then subjected to final annealing to prepare an annealed steel sheet.

As an insulating coating composition, 60 parts by weight of triethyl (trifluoromethyl) silane (triethyl (trifluoromethyl) silane), 20 parts by weight of chromic anhydride (CrO ₃ ), 10 parts by weight of magnesium oxide (MgO) and 5 parts by weight of ethylene glycol with distilled water The mixture was prepared in the form of a slurry, the slurry was applied to the final annealed steel sheet using a roll, and then heat-treated at 650 ° C. for 25 seconds and cooled in air. The electrical steel sheet was subjected to Stress Relief Annealing (SRA) at 100% nitrogen atmosphere at 820 ° C. for 2 hours, and then cooled in air. The thickness of the insulating film was about 0.8 mu m.

Examples 2-2 to 2-12

In the same manner as in Example 2-1, the content and type of the silane compound, the chromic acid compound, and the ceramic powder in the insulation coating composition were replaced as shown in Table 4 to form an insulation coating.

Comparative Example 2-1

In the same manner as in Example 2-1, without using a chromic acid compound, an insulating coating composition containing 100 parts by weight of triethyl (trifluoromethyl) silane (triethyl (trifluoromethyl) silane) was used.

Comparative Example 2-2

In the same manner as in Example 2-1, without using a silane compound, an insulating coating composition containing 100 parts by weight of chromic anhydride was used.

Comparative Example 2-3

In the same manner as in Example 2-1, without using a silane compound, an insulating coating composition including 60 parts by weight of chromic anhydride and 40 parts by weight of magnesium oxide was used.

The properties of the electrical steel sheets prepared in Examples and Comparative Examples were summarized in Table 5 below.

The iron loss (W _15/50) refers to the power loss that appears when sikyeoteul magnetized with the alternate current magnetic field frequency of 50Hz to 1.5Tesla.

In addition, the insulation properties were measured by using a Franklin meter in accordance with the ASTM A717 International Standard.

In addition, the adhesion is shown by the minimum arc diameter without film peeling when the specimen is bent 180 ° in contact with a 10 to 100 mm arc.

In addition, the surface characteristic is a result of visually evaluating the degree to which a uniform film is formed and a uniform color.

As shown in Table 4 and Table 5, it can confirm that the insulating film characteristic of an Example was excellent compared with the comparative example. In addition, when the silane compound or the chromic acid compound is included alone, peeling of the film occurs excessively and it can be confirmed that the magnetic properties are deteriorated.

6 is a scanning electron microscope (SEM) photograph of the cross section of the electrical steel sheet prepared in Example 2-2.

Figure 7 shows a scanning electron microscope (SEM) photograph of the surface of the electrical steel sheet prepared in Comparative Example 2-3. As shown in Figure 6, in the case of Example 2-2, it can be seen that the beautiful insulating film is maintained even after the SRA. On the other hand, as shown in Figure 7, in Comparative Example 2-3, after the SRA, it can be seen that a large number of cracks on the insulating film surface.

Experimental Example 2-2: Evaluation of the effect of the polymer resin addition

Example 2-11

4.5 wt% of silicon (Si), 0.80 wt% of aluminum (Al), 0.15 wt% of manganese (Mn), 0.001 wt% of titanium (Ti), 0.05 wt% of tin (Sn), and 0.004 of carbon (C) Wt%, nitrogen (N) 0.0015% by weight, phosphorus (P) 0.015% by weight, sulfur (S) 0.001% by weight, the balance was prepared a slab consisting of Fe and other unavoidable impurities.

The slab was heated at 1150 ° C. and hot rolled to a thickness of 2.3 mm to prepare a hot rolled sheet.

The hot rolled sheet was wound at 650 ° C., cooled in air, subjected to hot rolled sheet annealing at 1040 ° C. for 3 minutes, quenched in water, pickled, and cold rolled to a thickness of 0.35 mm to prepare a cold rolled sheet.

The cold rolled sheet was annealed at 1050 ° C. for 60 seconds at 30% hydrogen and 70% nitrogen at a dew point temperature of −40 ° C., followed by final annealing to prepare an annealed steel sheet.

Thereafter, the polymer resin was mixed in the insulating coating composition described in Example 2-2 as summarized in Table 6 to prepare a slurry, heat treated at 650 ° C. for 30 seconds, and cooled in air. The steel sheet was subjected to Stress Relief Annealing (SRA) heat treatment at 100% nitrogen atmosphere at 820 ° C. for 2 hours, and cooled in air. The insulating film was formed to a thickness of about 0.4 mu m.

The stress relief annealed steel sheet was treated for 24 hours at 60 ° C. and 95% humidity for 24 hours.

As shown in Table 6, changes in iron loss, surface roughness, area ratio, and rust generation area were confirmed according to the change in the type and amount of the polymer resin.

The present invention is not limited to the embodiments, but may be manufactured in various forms, and those skilled in the art to which the present invention pertains may change to other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that it may be practiced. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

[Description of the code]

100: electrical steel sheet

10: electric steel substrate

20: insulation film

Claims (32)

1. Electrical steel substrate and

   Insulating coating on one side or both sides of the electrical steel sheet substrate,

   The insulating film is an electrical steel sheet containing a silane compound and a metal hydroxide represented by the following formula (1).

   [Formula 1]

   

   (In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)
2. The method of claim 1,

   The silane compound is an electrical steel sheet represented by the following formula (2).

   [Formula 2]

   

   (In Formula 2, R ¹ and R ² are each independently hydrogen, a straight or branched alkyl group, a cyclo alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group or an aminoalkyl group, and L ¹ is directly A bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)
3. The method of claim 1,

   The silane compound may be triacetoxy methyl silane (Triacetoxy (methyl) silane), triacetoxy vinyl silane (Triacetoxy (vinyl) silane), dimethyldimethacroyloxy-1-ethoxysilane (Dimethyl-di (methacroyloxy-1) -Ethoxy) silane) and 3- (trimethoxysilyl) propylmethacrylate (3- (trimethoxysilyl) propylmethacrylate) electrical steel sheet containing at least one.
4. The method of claim 1,

   The metal hydroxide may be Ni (OH) ₂ , Co (OH) ₂ , Cu (OH) ₂ , Sr (OH) ₂ , Ba (OH) ₂ , Pd (OH) ₂ , In (OH) ₃ , (CH ₃ CO ₂ ) An electrical steel sheet comprising at least one of ₇ Cr ₃ (OH) ₂ , Bi (OH) _3, and Sn (OH) ₂ .
5. The method of claim 1,

   The insulating film further includes a metal nitride,

   An electrical steel sheet comprising 0.1 to 40% by weight of metal nitride, 25 to 75% by weight of silane compound and 0.5 to 60% by weight of metal hydroxide.
6. The method of claim 5,

   The metal nitride is an electrical steel sheet containing at least one of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .
7. The method of claim 1,

   The electrical steel sheet is an electrical steel sheet that satisfies the following general formula (1).

   [Formula 1]

   20≤ TC ≤ 200 W / mK

   (In Formula 1, TC represents a thermal conductivity value measured by PPMS (Physical Property Measurement System) after induction heating of a specimen of 600 × 400mm 230 ℃.
8. The method of claim 1,

   The electrical steel substrate is C: 0.01% by weight or less, Si: 6.0% by weight or less, P: 0.5% by weight or less, S: 0.005% by weight or less, Mn: 0.1 to 1.0% by weight, Al: 0.40 to 2.0% by weight, N : 0.005% by weight or less, Ti: 0.005% by weight or less and Sb, Sn, Ni or a combination thereof: 0.01 to 0.15% by weight, and the balance comprises Fe and inevitable impurities.
9. An insulating coating composition for electrical steel sheet comprising a silane compound represented by the following formula (1) and a metal hydroxide.

   [Formula 1]

   

   (In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)
10. The method of claim 9,

    Further includes metal nitrides,

    The insulating coating composition for electrical steel sheet containing 0.1-40 weight% of metal nitrides, 25-75 weight% of silane compounds, and 0.5-60 weight% of metal hydroxides based on solid content.
11. The method of claim 10,

    The metal nitride is an insulating coating composition for electrical steel sheet including at least one of BN, AlN, Si ₃ N ₄ , Mg ₃ N ₂ , Ca ₃ N ₂ , Sr ₃ N ₂ , Ba ₃ N ₂ , and Ge ₃ N ₄ .
12. Hot rolling the slab to produce a hot rolled plate, followed by cold rolling, and then preparing a steel sheet in which final annealing is completed; And

    Applying an insulating coating composition to the steel sheet to form an insulating coating,

    The insulating coating composition is a method for producing an electrical steel sheet comprising a silane compound represented by the following formula (1) and a metal hydroxide.

    [Formula 1]

    

    (In Formula 1, R ¹ and R ² are each independently hydrogen, straight or branched alkyl group, cyclo alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, alkoxy group or aminoalkyl group, and L is a direct bond. Or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)
13. The method of claim 12,

    Electrical steel sheet with an insulating coating is formed of the electrical steel sheet satisfies the following general formula (1).

    [Formula 1]

    20≤ TC ≤ 200 W / mK

    (In Formula 1, TC represents a thermal conductivity value measured by PPMS (Physical Property Measurement System) after induction heating of a specimen of 600x400mm 230 ℃.)
14. A silane compound represented by Formula 1 below; And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

    [Formula 1]

    

    In Formula 1, R ¹ is hydrogen, a halogen element, a straight 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, and L is a direct bond or a divalent linking group M is an integer from 1 to 4, n is 4-m.
15. The method of claim 14,

    An insulating coating composition for electrical steel sheet comprising 10 to 80 parts by weight of the silane compound and 20 to 90 parts by weight of the chromic acid compound, based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound.
16. The method of claim 14,

    In Formula 1, R ¹ is hydrogen, a halogen element, a linear or branched alkyl group or an alkoxy group insulation coating composition for electrical steel sheet.
17. The method of claim 14,

    In Chemical Formula 1, L is a direct bond, an alkylene group, and at least one of -CF ₂ -insulation coating composition for electrical steel sheet.
18. The method of claim 14,

    The silane compound is an insulating film composition for electrical steel sheet represented by the following formula (2).

    [Formula 2]

    

    R ¹ to R ³ in Formula 2 are each independently hydrogen, a halogen element, a straight 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, and L ₁ Is a direct bond or a divalent linking group, m is an integer from 1 to 4, n is 4-m.)
19. The method of claim 18,

    In Formula 2, R ² and R ³ are each independently an insulating coating composition for an electrical steel sheet which is hydrogen or a halogen element.
20. The method of claim 14,

    The silane compound is triethyl (trifluoromethyl) silane (triethyl (trifluoromethyl) silane), Trimethoxy (trifluoropropyl) silane (trimethoxy (propyl silane)), Dimethoxy-methyl (trifluoropropyl) silane (dimethoxy-) Insulation coating composition for electrical steel sheets containing at least 1 sort (s) of methyl (tripulo propyl) silane) and Perfluorooctyl-triethoxysilane (perfluorooctyl triethoxysilane).
21. The method of claim 14,

    The insulating coating composition for electrical steel sheet containing 0.5-65 weight part of ceramic powders with respect to 100 weight part of total amounts of the said silane compound and the said chromic acid compound.
22. The method of claim 21,

    The ceramic powder is _{MgO, MnO, Al 2 O 3} , SiO 2, TiO 2, ZrO 2, Al 6 Si 2 O 13, Al 2 O 3 · TiO 2, Y 2 O 3, 9Al 2 O 3 · B 2 O ₃ , BN, CrN, BaTiO ₃ , SiC and TiC, including an insulating coating composition for electrical steel sheet.
23. The method of claim 21,

    The average particle diameter of the ceramic powder is 0.05 to 20㎛ insulating film composition for electrical steel sheet.
24. The method of claim 21,

    Acrylic resin, styrene resin, vinyl acetate resin, polyester resin, urethane resin, polyethylene resin, polypropylene resin, polyamide resin, polycarbonate resin, phenol resin, based on 100 parts by weight of the total amount of the silane compound and the chromic acid compound Insulating coating composition for electrical steel sheet further comprising 0.5 to 30 parts by weight of at least one polymer resin of alkyd resin and epoxy resin.
25. The method of claim 14,

    1 to 15 weights of one or more of ethylene glycol, propylene glycol, glycerine, and butyl carbitol based on 100 parts by weight of the silane compound and the chromic acid compound. Insulating coating composition for electrical steel sheet comprising a further.
26. Electrical steel substrate and

    Insulating coating on one side or both sides of the electrical steel sheet substrate,

    The insulating film is a silane compound represented by the following formula (1); And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

    [Formula 1]

    

    In Formula 1, R ¹ is hydrogen, a halogen element, a straight 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, and L is a direct bond or a divalent linking group M is an integer from 1 to 4, n is 4-m.)
27. The method of claim 26,

    The insulating film is an electrical steel sheet containing 0.1 to 50% by weight of Si and 0.01 to 25% by weight of F.
28. The method of claim 26,

    The insulating film has a thickness of 0.1 to 10㎛ electrical steel sheet.
29. Preparing an electrical steel sheet substrate; And

    Forming an insulating coating by coating the insulating coating composition on one or both surfaces of the electrical steel sheet substrate,

    The insulating coating composition is a silane compound represented by the formula (1); And at least one chromic acid compound among chromic anhydride, chromate and dichromate.

    [Formula 1]

    

    In Formula 1, R ¹ is hydrogen, a halogen element, a straight 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, and L is a direct bond or a divalent linking group M is an integer from 1 to 4, n is 4-m.
30. The method of claim 29,

    The step of manufacturing the electrical steel sheet is

    Hot rolling the slab to produce a hot rolled plate;

    Cold rolling the hot rolled sheet to produce a cold rolled sheet;

    A method of manufacturing an electrical steel sheet comprising the final annealing of the cold rolled sheet.
31. The method of claim 29,

    Forming the insulating film is a method of manufacturing an electrical steel sheet comprising the step of heat-treating the steel sheet coated with the insulating film composition at a temperature of 100 to 680 ℃.
32. The method of claim 29,

    After forming the insulating film,

    Method for producing an electrical steel sheet further comprising the step of stress relief annealing at a temperature of 700 to 1000 ℃.

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