JP3375827B2 - Electrical steel sheet with insulating coating capable of strain relief annealing and excellent in corrosion resistance and solvent resistance, and method of forming the insulating coating - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention does not contain a harmful compound such as hexavalent chromium, can be manufactured by low temperature baking, can be strain relief annealed, and has a solvent resistance and a corrosion resistance before and after annealing. The present invention relates to a magnetic steel sheet with an insulating coating having good performance and a method for forming the insulating coating.

[0002]

2. Description of the Related Art Insulating coatings for electrical steel sheets not only have interlayer resistance, but also punchability, TIG weldability, coating adhesion, corrosion resistance (salt water spray resistance, wet resistance), solvent resistance, heat resistance, blocking resistance. Properties, tension pad resistance, corrosion resistance after strain relief annealing, and baking resistance are required, and various insulating coatings have been developed according to applications. Further, the electromagnetic steel sheet is often subjected to strain relief annealing at about 750 to 850 ° C. in order to improve the magnetic properties after punching. There are three types of insulation coatings: (1) an inorganic coating that emphasizes weldability and heat resistance, (2) an organic resin-containing semi-organic coating that aims to achieve both punchability and weldability, and (3) a special-purpose organic coating. It is roughly classified, but it is the coating containing the inorganic substances of (1) and (2) that withstands strain relief annealing, and in particular,
As a material corresponding to (2), a chromate-based insulating coating containing an organic resin is widely used because it can significantly improve punching performance as compared with an inorganic insulating coating.

For example, Japanese Patent Publication No. 60-36476 discloses that
An electromagnetic wave obtained by applying a treatment liquid prepared by mixing a vinyl chromate / veova resin emulsion and an organic reducing agent into a dichromate-based aqueous solution containing at least one divalent metal on the surface of a dough iron plate and performing a baking process by a conventional method. A method for forming an insulating film on a steel sheet is disclosed. This electrical steel sheet with an insulating coating satisfies various performances such as corrosion resistance and solvent resistance. However, the chromate-based coating needs to be baked at a relatively high temperature in order to reduce hexavalent chromium to trivalent and insolubilize it. Further, since hexavalent chromium is highly toxic, there is a concern about environmental pollution, and exhaust treatment and waste liquid treatment are costly.

Further, baking at a high temperature leads to an increase in cost from the viewpoint of an increase in energy consumption during manufacturing and a decrease in insulating film processing speed. Further, in the case of a semi-organic coating, the resin is thermally deteriorated during baking, which may impair the original performance of the resin.

As a technique using an inorganic substance other than chromic acid, a semi-organic insulating coating containing a phosphate is also under study. However, it is necessary to bake the phosphate at a higher temperature after coating in order to promote the dehydration reaction and make it insoluble.

As a semi-organic insulating coating which can be baked at a relatively low temperature and does not contain chromic acid, Japanese Patent Laid-Open No. 54-3 / 54 is available.
No. 1598, a treatment liquid comprising silica hydrosol and an organic substance is applied to the surface of a steel sheet and heated at a temperature of 100 to 350 ° C. to have heat resistance having a coating film containing silica as a main component containing an organic substance, An electromagnetic steel sheet having a bake-resistant coating and a surface treatment method thereof are disclosed.
In addition, in Japanese Examined Patent Publication No. 59-21927, the heat at the time of continuous annealing is used, and then an aqueous solution containing an inorganic colloidal substance as a main component and a water-soluble or emulsion-type resin is applied, and the tempering is performed as it is. A method of applying a strain relief annealing anti-seizure coating to an electromagnetic steel sheet by rolling is disclosed.

[0007]

Problems to be Solved by the Invention JP-A-54-3159
No. 8 and Japanese Patent Publication No. 59-21927,
Its main purpose is to prevent seizure after annealing. JP-A-5
The silica hydrosol described in 4-31598 and the inorganic colloidal material described in JP-B-59-21927 are
Certainly, it can be baked at a lower temperature than chromate-based and phosphate-based coatings. That is, since chromate-based and phosphate-based compounds prevent stickiness, it is necessary to promote a film-forming reaction from water-soluble to water-insoluble by heating at high temperature, but inorganic colloidal substances are not required.
However, both are simply due to the combination of silica hydrosol or inorganic colloidal substance and resin, there is no regulation regarding the resin, such as corrosion resistance and solvent resistance, performance other than baking resistance after annealing is inferior, Was limited.

Specifically, in JP-A-54-31598, as is clear from the examples, the comparative examples containing chromate do not cause rust in the wetting test, but the invention. In each of the examples, spot rust occurs. In Japanese Examined Patent Publication No. 59-21927, there is no description about corrosion resistance and the like, so that the vinegar beer used only in Examples is used.
As a result of investigating the performance of the electrical steel sheet with an insulating coating made of an acrylic copolymer resin and various inorganic colloidal substances, the performance such as corrosion resistance and solvent resistance was insufficient.

The present invention has been made to solve the above-mentioned problems, and can be manufactured by low temperature baking, strain relief annealing is possible, and excellent corrosion resistance and solvent resistance are exhibited without using chromate. In addition, the present invention provides a magnetic steel sheet with an insulating coating and a method for forming the insulating coating, which satisfies other coating performances.

[0010]

Means for Solving the Problems As a result of investigations aimed at solving the above-mentioned problems, the inventors have used a specific ethylene-based resin containing no emulsifier and silica obtained by a limited production method. Thus, it was found that a magnetic steel sheet with an insulating coating, which can be manufactured by low-temperature baking, can be subjected to strain relief annealing, and is excellent in various properties such as corrosion resistance and solvent resistance, can be obtained. Furthermore, by adding a predetermined amount of a silane coupling agent and / or a Na-based passivating agent, salt spray resistance, boiling water vapor exposure resistance, corrosion resistance after annealing, etc. are dramatically improved, and conventional chromic acid It was found that corrosion resistance equal to or higher than that of an insulating coating mainly composed of is obtained, and the present invention has been completed.

According to the invention: (a) an ethylene-unsaturated carvone having a melting point above 60 ° C.
An acid copolymer (b) containing silica (a) and (b), and further (c) a silane coupling agent (d) a passivating agent (excluding chromium compounds, preferably Na .
₂ MoO ₄ , NaNO ₂ , Na ₂ WO ₄ , CH ₃ COONa, and C ₆ H ₅ COONa
At least one Na-based passivating agent selected from (c) and (d),
The solid content weight ratio of (a) / (b) / (c + d) is 100.
/20-500/0.1-50 and contains no emulsifier
There is provided a magnetic steel sheet with an insulating coating, which is capable of strain relief annealing and is excellent in corrosion resistance and solvent resistance, characterized in that the surface of the magnetic steel sheet is coated with a non- insulating coating and dried . here
Thus, the resin is one in which the melting point of the ethylene-unsaturated carboxylic acid copolymer is higher than 60 ° C. and does not contain an emulsifier.
Preferably, the ethylene-unsaturated carboxylic acid copolymer,
It is a self-emulsifying ethylene-unsaturated carboxylic acid copolymer.
In particular, an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer is particularly preferable. Furthermore, the adhesion amount of the insulating coating is 0.05-
It is preferably 4 g / m ² .

Further, in order to obtain the above-mentioned insulating coated electromagnetic steel sheet, as a first method of the present invention, (a) an ethylene-unsaturated carvone having a melting point of more than 60 ° C.
An aqueous solution or aqueous dispersion of an acid copolymer (preferably an aqueous dispersion of a self-emulsifying ethylene-unsaturated carboxylic acid copolymer), (b) colloidal silica, and (a) and (b), , (C) silane coupling agent (d) passivating agent (excluding chromium compounds, preferably Na
₂ MoO ₄ , NaNO ₂ , Na ₂ WO ₄ , CH ₃ COONa, and C ₆ H ₅ COONa
At least one Na-based passivating agent selected from (c) and (d), and the solid content weight ratio of (a) / (b) / (c + d) is 1
00/20 to 500 / 0.1 to 50 and does not contain an emulsifier.
The amount of adhesion of an aqueous composition having no dryness is 0.05 to 4
It is applied to the surface of the electrical steel sheet so that it becomes g / m ^2, and 80 to 2
Provided is a method for forming an insulating coating on a magnetic steel sheet which is capable of strain relief annealing and is excellent in corrosion resistance and solvent resistance, which is characterized in that an aqueous medium is dried at a steel sheet arrival temperature of 50 ° C. here,
An aqueous dispersion of an ethylene-unsaturated carboxylic acid copolymer,
Water of self-emulsifying ethylene-unsaturated carboxylic acid copolymer
It is preferably an organic dispersion, and particularly preferably an aqueous dispersion of an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer.

Further, as a second method of the present invention, a (c ₁ ) silane coupling agent diluted with an aqueous medium is applied to the surface of the magnetic steel sheet, and then a (c ₂ ) silane coupling agent (a) is applied. Ethylene-unsaturated carvone having a melting point above 60 ° C
Aqueous solution or aqueous dispersion of acid copolymer (b) containing colloidal silica (c ₂ ), (a) and (b) and containing an emulsifier
A non- aqueous composition is (c ₁ ) / (c ₂ ) / (a) / (b)
The undiluted weight ratio of 0.1 to 50/0 to 50 (wherein the total amount of (c ₁ ) + (c ₂ ) is 0.1 to 50 parts by weight) / 100
/ 20 to 500, the amount of adhesion after drying is 0.05 to 4 g / m
² is applied, and the aqueous medium is dried and removed at a steel plate reaching temperature of 80 to 250 ° C., which is capable of strain relief annealing and is excellent in corrosion resistance. Provided. Resin (a) is self-milk
Dispersion of water-soluble ethylene-unsaturated carboxylic acid copolymer
And an aqueous dispersion of an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer is particularly preferable.

As a third method of the present invention, a passivating agent (excluding chromium compounds) (d) on the surface of the electromagnetic steel sheet.
And an aqueous composition (A) consisting of an aqueous inorganic substance (b ₁ ) selected from colloidal silica and an aqueous solution of an alkali silicate, and then the silane coupling agent (c) and the melting point of 60 ° C. on the same coated surface. Is ethylene-unsaturated carbo
An aqueous emulsifier-free aqueous composition (B) comprising an aqueous solution of an acid copolymer or an aqueous dispersion (a) has an insulating coating amount after drying of 0.05 to 4 g / m ² , (d) / ( b ₁ ) /
The solid content weight ratio of (c) / (a) is (0.1-50) /
(20 to 500) / (0.1 to 50) / 100 is applied, and the aqueous medium is dried at a steel plate reaching temperature of 80 to 250 ° C., which enables stress relief annealing, and after annealing. A method for forming an insulating coating on an electromagnetic steel sheet with an insulating coating having excellent corrosion resistance is provided. Where ethylene-unsaturated carbo
The aqueous dispersion of the acid copolymer is preferably an aqueous dispersion of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer. Passivating agent (d) is Na ₂ MoO ₄ , Na
It is preferable that it is at least one Na-based passivating agent selected from NO ₂ , Na ₂ WO ₄ , CH ₃ COONa, and C ₆ H ₅ COONa.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. The steel plate used in the present invention is an electromagnetic steel plate (electric iron plate,
Electromagnetic steel sheet). The shape of the steel plate is not limited, and may be plate-shaped, sheet-shaped, or coil-shaped.

The resin constituting the insulating coating of the present invention is preferably an aqueous resin, preferably an ethylene / unsaturated carboxylic acid copolymer. Examples of the ethylene / unsaturated carboxylic acid copolymers include random copolymers, copolymers grafted with polyethylene unsaturated carboxylic acid, and terpolymers to which a third component is added. As the unsaturated carboxylic acid, for example, acrylic acid,
Examples of the unsaturated carboxylic acid having usually 6 or less carbon atoms such as methacrylic acid, crotonic acid and isocrotonic acid, and examples of the dicarboxylic acid include maleic acid, fumaric acid and itaconic acid.

The ethylene-unsaturated carboxylic acid copolymer used in the present invention contains no emulsifier . That is, in order to form an insulating coating film containing an ethylene-unsaturated carboxylic acid copolymer, a method of applying the aqueous paint-formed copolymer to a steel sheet is suitable. (Surfactant) is not used . This is because when the emulsifier is present in the insulating coating, the corrosion resistance, which is the main object of the present invention, becomes insufficient. In the present invention, an aqueous dispersion of a self-emulsifying ethylene-unsaturated carboxylic acid copolymer is suitable. Generally, if the copolymerization ratio of unsaturated carboxylic acid is about 10% by weight or more, self-emulsification is possible. The aqueous paint is preferably a dispersion rather than an aqueous solution of resin. The resin dispersion liquid (emulsion, dispersion, latex) has a lower liquid viscosity, is excellent in dispersibility with silica described later, and is easy to apply.

In order to disperse the resin in water, it is necessary to partially neutralize the unsaturated carboxylic acid with a basic substance.
Bases used for this neutralization include alkali metals such as sodium hydroxide, lithium hydroxide and potassium hydroxide, zinc such as zinc hydroxide, zinc acetate and zinc oxide, ammonia, morpholine, triethylamine and amino alcohol. The following amines are commonly used.

The ethylene-unsaturated carboxylic acid copolymer used in the present invention has a melting point of 6 after forming an insulating film.
It shall be over 0 ° C. If the melting point is below 60 ° C,
In addition to insufficient corrosion resistance at high temperatures, blocking may occur during the winding step immediately after baking or during coil transportation, or the coating may be damaged by the tension pad immediately after baking. The upper limit of the melting point is necessarily around 130 ° C. because ethylene is the main component. Since the melting point of the resin after baking substantially correlates with the minimum film forming temperature of the self-emulsifying ethylene-unsaturated carboxylic acid copolymer emulsion, it is effective to set the minimum film forming temperature to 60 to 130 ° C.

Particularly preferred as the ethylene-unsaturated carboxylic acid copolymer used in the present invention is an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer. In particular, the one using methacrylic acid as the unsaturated carboxylic acid is suitable from the viewpoint of corrosion resistance, and the one obtained by neutralizing the unsaturated carboxylic acid with sodium hydroxide or potassium hydroxide is preferable. Usually, the amount of unsaturated carboxylic acid in the ionomer is 10 to 30% by weight, preferably 15 to 25% by weight. The rate of neutralization of unsaturated carboxylic acids with metal ions is preferably 50 to 80% of all unsaturated carboxylic acids. When the amount of the unsaturated carboxylic acid and the neutralization ratio thereof are out of the preferred range, it becomes difficult to disperse the aqueous solution. Examples of the method for dispersing the ionomer in water include adding the ionomer to water and stirring the mixture at a high temperature of 100 to 200 ° C. under pressure.

In the ethylene-unsaturated carboxylic acid copolymer used in the present invention, the performance of the insulating coating and the workability of coating are improved by adding reactive functional groups to the extent that the effects of the present invention are not impaired. From the viewpoints of improving the film forming property and reducing the cost, other monomers can be copolymerized. For example, an alkyl ester such as 1-butyl methacrylate or n-butyl acrylate, a vinyl ester such as vinyl acetate, vinyl alcohol, styrene or the like can be copolymerized. Also, an isocyanate compound,
It is also possible to mix a crosslinking agent such as a dihydrazide compound, an aziridine compound, an epoxy compound or other aqueous resin.

The silica constituting the insulating coating of the present invention is obtained by applying silica dispersed in water to a steel plate. Any form of silica may be used as long as it can be dispersed in water, and various forms such as colloidal silica, vapor phase silica, and aggregated silica can be applied.
Of these, colloidal silica is preferable. The silica may be surface-treated with aluminum or the like.

As a first method for forming the above-mentioned insulating coating, a resin (a) and a colloidal silica (b) are mixed, and at least one selected from the following (c) and (d) is contained. Application of the aqueous composition to the surface of the steel sheet may be mentioned. The mixing ratio of (a) and (b) is, in terms of solid content, ethylene-unsaturated carboxylic acid copolymer 10
20 to 500 parts by weight of silica is suitable for 0 parts by weight. It is more preferably 50 to 300 parts by weight.
When the amount of silica is less than 20 parts by weight, the seizure resistance during strain relief annealing is poor. In addition, the corrosion resistance after strain relief annealing is low. If it exceeds 500 parts by weight, punching property and corrosion resistance are poor.

In mixing the aqueous dispersion of the ethylene-unsaturated carboxylic acid copolymer and colloidal silica,
It is preferable that the hydrogen ion concentrations (pH) of both are as uniform as possible. Usually, these pHs are adjusted within the range of 8 to 11, and the above-mentioned various alkali metals and amines can be used to adjust the pH. If the pH values of the two are significantly different, the aqueous dispersion of the ethylene-unsaturated carboxylic acid copolymer may aggregate when mixed.

The silane coupling agent (c) constituting the insulating coating of the present invention comprises an ethylene-unsaturated carboxylic acid copolymer, a reactive group having an interaction such as a chemical bond and compatibilization, and an alkoxysilyl group. Things are selected.
As the reactive group, a vinyl group, a hexenyl group, a mercapto group such as γ-mercaptopropyl, an epoxy group such as γ-glycidoxypropyl, a methacrylic group such as γ-methacryloxypropyl, γ-aminopropyl, N-β ( Amino groups such as aminoethyl) γ-aminopropyl and N-β (N-vinylbenzylaminoethyl) -γ-aminopropyl are exemplified. Examples of the alkoxysilyl group include trimethoxysilane, triethoxysilane, methyldimethoxysilane and the like.

When the silane coupling agent is added to the aqueous composition, it is usually added after being dissolved or dispersed in water. In particular, it is preferable to completely dissolve it in water, and it is also effective to add alcohol or acetic acid to dissolve it.

As the passivating agent (d) constituting the insulating coating of the present invention, a Na-based passivating agent is preferable, and Na ₂ MoO ₄ ,
_{NaNO 2, Na 2 WO 4,} CH 3 COONa, and the like C ₆ H ₅ COONa et al. You may use these hydrates. Also, usually, these are dissolved in water in advance and then added to the aqueous composition.

The silane coupling agent and passivating agent are
By using one of them as one of the constituents of the insulating coating, performance such as corrosion resistance can be improved.
Both are preferably used. The method for interposing the silane coupling agent and the passivating agent in the insulating coating is not specified, but an aqueous solution or dispersion of the silane coupling agent and the passivating agent, an aqueous dispersion of the ethylene-unsaturated carboxylic acid copolymer. The body and colloidal silica can be mixed simultaneously. Alternatively, the silane coupling agent or the passivating agent can be mixed in advance with the aqueous dispersion of the ethylene-unsaturated carboxylic acid copolymer or the colloidal silica.

The silane coupling agent and the passivating agent may be mixed alone or in a total amount of 0.1 to 50 parts by weight with respect to 100 parts by weight of the solid content of the resin. If it is less than 0.1 parts by weight, the effect of improving the performance such as corrosion resistance will be small, and if it exceeds 50 parts by weight, the aqueous composition may be agglomerated or the performance of the insulating coating may be deteriorated.

The ethylene-unsaturated carboxylic acid copolymer, silica, silane coupling agent and passivating agent which constitute the insulating coating may be used in combination of plural kinds.

An insulating coating is formed by applying the mixed aqueous dispersion composition to one side or both sides of a steel sheet and baking it. As a coating method, various methods such as a roll coater, a flow coater, a spray coating, and a knife coater which are generally used in industry can be applied. As for the baking method, a hot air method, an infrared method, an induction heating method or the like which is usually carried out can be used and is not particularly limited. The baking temperature is preferably in the range of 80 to 250 ° C. at the steel plate reaching temperature. If it is lower than 80 ° C, the removal of the aqueous medium by drying may be insufficient. If the temperature exceeds 250 ° C, the resin may deteriorate due to heat, and the original performance of the resin may be impaired.
It is not preferable because the silane coupling agent may evaporate. The baking temperature is appropriately set according to the film forming temperature of the aqueous dispersion of the ethylene-unsaturated carboxylic acid copolymer, the amount of the insulating coating attached, and the like.

The adhesion amount of the insulating coating after drying is 0.05 to 4
g / m ^2, preferably set at 0.2 to 1.5 g / m ^2. The amount of adhered poor resistance to seizure resistance is less than 0.05 g / m ^2, weldability is 4g / m ^2, greater than blocking resistance, adhesion is poor.

The insulating coating film and the aqueous dispersion composition of the present invention include, as a known additive, an amino-type passivating agent for the purpose of improving various properties and coating workability of an electromagnetic steel sheet with an insulating coating film. Anticorrosion agent, lubricant, defoaming agent, dispersant, repellant, anti-scratch agent, inorganic pigment, organic pigment, dye, surfactant, water repellent, thickener, film forming aid, preservative, etc. Can be added.

In the second method of the present invention, as the silane coupling agent to be used, both (c ₁ ) and (c ₂ ) are chemically bonded to the resin and compatibilized in the same manner as in the above-mentioned first method. A reactive group having an interaction and an alkoxysilyl group are selected. As the reactive group, vinyl group, hexenyl group, mercapto group such as γ-mercaptopropyl, epoxy group such as γ-glycidoxypropyl, γ-
Methacryl groups such as methacryloxypropyl, γ-aminopropyl, N-β (aminoethyl) γ-aminopropyl, N-β (N-vinylbenzylaminoethyl) -γ-
Amino groups such as aminopropyl are exemplified. Examples of the alkoxysilyl group include trimethoxysilane, triethoxysilane, methyldimethoxysilane and the like.

Examples of the aqueous medium for diluting the silane coupling agent include water, water-soluble solvents such as alcohols and cellosolves, and mixtures thereof. Although the degree of dilution can be adjusted as appropriate, it is usually diluted 5- to 500-fold. The silane coupling agent is preferably completely dissolved in the aqueous medium. It is also effective to add acetic acid or the like to dissolve it. The silane coupling agent diluted with an aqueous medium is required to be applied to the surface of the electromagnetic steel sheet in advance, but it is preferable that the aqueous solution or aqueous dispersion of (a) resin and (b) aqueous colloidal silica described later be used. It is also included in the composition.

As the resin (a) constituting the insulating coating of the present invention, a resin in the form of an aqueous solution or an aqueous dispersion is used. A dispersion is preferable to an aqueous resin solution. This is because the resin dispersion (emulsion, dispersion, latex) has a lower liquid viscosity, is excellent in dispersibility with silica described later, and is easy to apply. The resin is an ethylene-unsaturated carboxylic acid copolymer, and examples thereof include a random copolymer, a copolymer in which an unsaturated carboxylic acid is grafted on polyethylene, or a terpolymer obtained by adding a third component. . As the unsaturated carboxylic acid, for example, acrylic acid,
Examples of the unsaturated carboxylic acid having usually 6 or less carbon atoms such as methacrylic acid, crotonic acid and isocrotonic acid, and examples of the dicarboxylic acid include maleic acid, fumaric acid and itaconic acid.

Among the ethylene-unsaturated carboxylic acid copolymers, no emulsifier is included . That is, an emulsifier (surfactant) is not used as a means for converting the ethylene-unsaturated carboxylic acid copolymer into an aqueous paint . When the emulsifier is present in the insulating coating, the corrosion resistance, which is the main object of the present invention, may be insufficient. In the present invention, an aqueous dispersion of a self-emulsifying ethylene-unsaturated carboxylic acid copolymer is suitable. Generally, if the copolymerization ratio of unsaturated carboxylic acid is about 10% by weight or more, self-emulsification is possible.

In order to disperse the resin in water, it is necessary to partially neutralize the unsaturated carboxylic acid with a basic substance.
Bases used for this neutralization include alkali metals such as sodium hydroxide, lithium hydroxide and potassium hydroxide, zinc such as zinc hydroxide, zinc acetate and zinc oxide, ammonia, morpholine, triethylamine and amino alcohol. The following amines are commonly used.

More specifically, preferred examples of the resins are the ionomers of ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymers among the ethylene-unsaturated carboxylic acid copolymers. In particular, the one using methacrylic acid as the unsaturated carboxylic acid is suitable from the viewpoint of corrosion resistance, and the one obtained by neutralizing the unsaturated carboxylic acid with sodium hydroxide or potassium hydroxide is preferable. Usually, the amount of unsaturated carboxylic acid in the ionomer is 10 to 30.
% By weight, preferably 15 to 25% by weight. The rate of neutralization of unsaturated carboxylic acids with metal ions is preferably 50 to 80% of all unsaturated carboxylic acids. If the amount of the unsaturated carboxylic acid and the neutralization ratio thereof are out of the preferred range, it becomes difficult to disperse the aqueous solution, or various performances such as corrosion resistance become low. Examples of the method for dispersing the ionomer in water include adding the ionomer to water and stirring the mixture at a high temperature of 100 to 200 ° C. under pressure.

From the viewpoint of improving the performance of the insulating coating, improving the workability of coating, improving the film forming property, and reducing the cost, the resin used in the present invention may be any other resin within the range that does not impair the effects of the present invention. The monomers can be copolymerized. For example,
Examples thereof include alkyl esters such as 1-butyl methacrylate and n-butyl acrylate, vinyl esters such as vinyl acetate, vinyl alcohol and styrene. Further, a crosslinking agent such as an isocyanate compound, a dihydrazide compound, an aziridine compound or an epoxy compound, or another aqueous resin can be mixed.

The resin used in the present invention has a melting point of more than 60 ° C. after the insulating coating is formed . If the melting point is less than 60 ° C, the corrosion resistance at high temperature may be insufficient, and blocking may occur during the winding process immediately after baking or during coil transportation, or the coating may be damaged by the tension pad immediately after baking. is there.

The silica constituting the insulating coating of the present invention can be obtained by applying silica dispersed in water to a steel plate. Any form of silica may be used as long as it can be dispersed in water, and various forms such as colloidal silica, vapor phase silica, and aggregated silica can be applied.
Of these, colloidal silica is preferable. The silica may be surface-treated with aluminum or the like.

The insulating coating of the present invention comprises a (c ₁ ) silane coupling agent previously applied to a magnetic steel sheet, an aqueous solution or dispersion of a resin (a) constituting an aqueous composition to be subsequently applied, and (b) ) Colloidal silica, and optionally a (c ₂ ) silane coupling agent. The mixing ratio of these is the weight ratio of the undiluted component and is (c ₁ ) / (c
₂ ) / (a) / (b) = 0.1-50 / 0-50 / 100
It is preferably in the range of / 20 to 500. In the case of (a) resin and (b) colloidal silica, it refers to the solid content weight ratio. The undiluted silane coupling agent is usually liquid.

The total amount of the silane coupling agent (c ₁ ) + (c ₂ ) is in the range of 0.1 to 50 parts by weight with respect to 100 parts by weight of the resin solid content. If it is less than 0.1 parts by weight, the effect of improving the performance such as corrosion resistance will be small, and if it exceeds 50 parts by weight, the aqueous composition may be agglomerated or the performance of the insulating coating may be deteriorated. The ratio of the silane coupling agent applied beforehand is preferably 0.1 to 30 parts by weight.

A suitable mixing ratio of silica is 20 to 500 parts by weight. It is more preferably 50 to 300 parts by weight. When the amount of silica is less than 20 parts by weight, seizure resistance during strain relief annealing is poor. In addition, the corrosion resistance after strain relief annealing is low. If it exceeds 500 parts by weight, punching property and corrosion resistance are poor.

When the colloidal silica and the aqueous solution or dispersion of the resin are mixed, it is preferable that the hydrogen ion concentrations (pH) of both are as uniform as possible.
Usually, their pH is adjusted within the range of 8-11 and p
For the adjustment of H, the above-mentioned various alkali metals and amines can be used. If the pH values of the two are significantly different, the resin may aggregate when mixed.

The silane coupling agent, the aqueous solution or dispersion of the resin, and the colloidal silica constituting the insulating coating may be used in combination of plural kinds.

In the second method of forming an insulating coating in the present invention, first, a silane coupling agent diluted with an aqueous medium is applied to one or both sides of an electromagnetic steel sheet, and subsequently, an aqueous composition in which the above-mentioned respective components are mixed. An insulating coating is formed by applying an object over a coated surface and baking it. For each coating method, various methods such as a roll coater, a flow coater, a spray coating, and a knife coater that are commonly used in industry can be applied. As for the baking method, a hot air method, an infrared method, an induction heating method or the like which is usually carried out can be used and is not particularly limited. The baking temperature is in the range of normal temperature to 250 ° C. for the silane coupling agent diluting liquid applied first. The aqueous composition can be subsequently applied with the aqueous medium remaining. If it exceeds 250 ° C, the silane coupling agent may evaporate, which is not preferable. It is also effective to preheat the steel sheet to promote evaporation of the aqueous medium.

After applying the aqueous composition, the baking temperature is preferably in the range of 80 to 250 ° C. at the steel plate reaching temperature. If it is lower than 80 ° C, the removal of the aqueous medium by drying may be insufficient. If the temperature exceeds 250 ° C, the resin may deteriorate due to heat, and the original performance of the resin may be impaired.
It is not preferable because the silane coupling agent may evaporate. The baking temperature is appropriately set according to the film forming temperature of the resin, the adhesion amount of the insulating film, and the like.

The amount of the insulating film deposited after drying is 0.05 to 4
g / m ^2, preferably set at 0.2 to 1.5 g / m ^2. The amount of adhered poor resistance to seizure resistance is less than 0.05 g / m ^2, weldability is 4g / m ^2, greater than blocking resistance, adhesion is poor.

The insulating coating and the aqueous dispersion composition of the present invention are used as well-known additives such as passivating agents and rust preventives for the purpose of improving various performances and coating workability of the electromagnetic steel sheet with an insulating coating. Agents, lubricants, defoamers, dispersants, repellants,
An anti-scratch agent, an inorganic pigment, an organic pigment, a dye, a surfactant, a water repellent, a thickener, a film forming aid, an antiseptic and the like can be added.

In the third method of the present invention, the passivating agent (d) constituting the aqueous composition (A) initially applied to the surface of the magnetic steel sheet is the same as that used in the first method. , Na ₂ MoO ₄ , NaNO ₂ , Na ₂ WO ₄ , CH ₃ COONa,
Examples include Na-based passivating agents such as C ₆ H ₅ COONa and organic passivating agents such as amine-based passivating agents. A hydrate may be used for these. Usually, what was previously dissolved in an aqueous medium is added to the aqueous composition.

The aqueous inorganic substance (b ₁ ) constituting the aqueous composition (A) is colloidal silica or an aqueous solution of alkali silicate. The shape of silica may be any manufacturing method as long as it can be dispersed in water, colloidal silica,
Various materials such as vapor phase silica and agglomerated silica are applicable. These may be surface-treated with aluminum or the like. The alkaline silicate aqueous solution is called water glass, and examples of the alkaline species include Li, Na, and K. Any of these may be used in combination.

As a method for applying the aqueous composition (A) to the surface of the magnetic steel sheet, various methods such as a roll coater, a flow coater, a spray coating and a knife coater generally used in industry can be applied. As a drying method, a hot air method, an infrared method, an induction heating method or the like which is usually carried out can be used and is not particularly limited. It is also possible to heat the electromagnetic steel sheet in advance and dry it by using the residual heat.
The effects of the present invention may be obtained without completely drying and removing the aqueous medium.

As the silane coupling agent (c) which constitutes the aqueous composition (B) to be subsequently applied, a reactive group having an interaction such as a chemical bond or compatibilization with the resin (a) described below and an alkoxysilyl group are used. The one consisting of is selected. As the reactive group, vinyl group, hexenyl group, γ
-Mercapto groups such as mercaptopropyl, epoxy groups such as γ-glycidoxypropyl, methacryl groups such as γ-methacryloxypropyl, γ-aminopropyl, N
-Β (aminoethyl) γ-aminopropyl, N-β (N
Examples thereof include amino groups such as -vinylbenzylaminoethyl) -γ-aminopropyl. Examples of the alkoxysilyl group include trimethoxysilane, triethoxysilane, methyldimethoxysilane and the like. When the silane coupling agent is added to the aqueous composition (B), it is preferable that it is completely dissolved, and it is also effective to add alcohol or acetic acid to dissolve it.

As the resin (a) constituting the aqueous composition (B), one in the form of an aqueous solution or an aqueous dispersion is used. The resin (a) is an ethylene-unsaturated carbohydrate having a melting point of more than 60 ° C. after the insulating coating is formed.
Acid copolymer . If the melting point is lower than 60 ° C, the corrosion resistance at high temperatures may be insufficient, blocking may occur during the product winding process or coil transportation, and the coating may be scratched by the tension pad. Further, the resin (a) does not contain a surfactant such as an emulsifier .
It This is because when the emulsifier is present in the insulating coating, the corrosion resistance, which is the main object of the present invention, may be insufficient.

Particularly suitable as the resin (a) is an aqueous dispersion of an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer. In particular, the one using methacrylic acid as the unsaturated carboxylic acid is suitable from the viewpoint of corrosion resistance, and the one obtained by neutralizing the unsaturated carboxylic acid with sodium hydroxide or potassium hydroxide is preferable. Usually, the amount of unsaturated carboxylic acid in the ionomer is 1
It is 0 to 30% by weight, preferably 15 to 25% by weight. The neutralization ratio of unsaturated carboxylic acid with metal ions is
It is preferably 50 to 80% with respect to the unsaturated carboxylic acid. When the amount of the unsaturated carboxylic acid and the neutralization ratio thereof are out of the preferred range, it becomes difficult to disperse the aqueous solution.

From the viewpoint of improving the performance of the insulating coating, improving the workability of coating, improving the film-forming property, and reducing the cost, the resin (a) may contain other monomers as long as the effects of the present invention are not impaired. It can be polymerized. Further, a crosslinking agent such as an isocyanate compound, a dihydrazide compound, an aziridine compound or an epoxy compound, or another aqueous resin may be mixed.

The passivating agent (d) and the aqueous inorganic substance (b ₁ ) constituting the aqueous composition (A), the silane coupling agent (c) and the resin (a) constituting the aqueous composition (B).
The mixing ratio of is, in the finally formed insulating film,
The solid content weight ratio of (d) / (b ₁ ) / (c) / (a) is (0.1-50) / (20-500) / (0.1-5).
It should be 0) / 100.

When the solid content weight ratio of the passivating agent (d) is less than 0.1 parts by weight with respect to 100 parts by weight of the solid content of the resin (a), the effect of improving the corrosion resistance after annealing and the like. Is small, and if it exceeds 50 parts by weight, the corrosion resistance before annealing may be deteriorated. When the solid content weight ratio of the aqueous inorganic substance (b ₁ ) is less than 20 parts by weight, the baking resistance during annealing and the interlayer resistance may be poor. If it exceeds 500 parts by weight, the punchability may be poor. The solid content weight ratio of the silane coupling agent (c) (weight ratio of undiluted content) is 0.
If it is less than 1 part by weight, the effect of improving the corrosion resistance before and after annealing becomes small, and if it exceeds 50 parts by weight, the aqueous composition may cause aggregation.

After the aqueous composition (A) is applied to the surface of the magnetic steel sheet, the aqueous composition (B) is subsequently applied and dried. As the coating method, various methods such as a roll coater, a flow coater, a spray coating, and a knife coater which are generally used in the industry can be applied as in the above.
As a drying method, a hot air method, an infrared method, an induction heating method or the like which is usually carried out can be used and is not particularly limited. The baking temperature is preferably in the range of 80 to 250 ° C. at the steel plate reaching temperature. If it is lower than 80 ° C, the removal of the aqueous medium by drying may be insufficient. If it exceeds 250 ° C., the resin is thermally deteriorated, the original performance of the resin may be impaired, and the silane coupling agent may evaporate, which is not preferable. The baking temperature is appropriately set according to the minimum film forming temperature of the resin (a) and the coating amount.

The adhesion amount of the insulating coating after drying is 0.05 to 4
g / m ^2, preferably set at 0.2 to 1.5 g / m ^2. Anti seizure property deposited amount is less than 0.05 g / m ^2, interlayer resistance, inferior and corrosion resistance, weldability is 4g / m ^2, greater than the blocking resistance, sometimes such adhesion is inferior.

The aqueous composition (A) used in the present invention,
(B) or the finally obtained magnetic steel sheet with an insulating coating, a known additive such as a rust preventive agent, a lubricant, a defoaming agent, or a dispersing agent is added for the purpose of improving various properties of the insulating coating and coating workability. Agents, anti-repellent agents, anti-scratch agents, inorganic pigments, organic pigments, dyes, surfactants, water repellents, thickeners, film forming aids, preservatives and the like can be added.

[0064]

EXAMPLES The effects of the present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

(Example 1) (Invention Example 1-1) On the surface of a magnetic steel sheet having a thickness of 0.5 mm,
The aqueous dispersion composition shown below was applied using a roll coater, and hot-air drying and baking were performed at a steel plate arrival temperature of 120 ° C. and a heating time of 10 seconds. The amount of the insulating coating attached after baking was 0.5 g / m ² . The obtained insulating coated steel sheet was allowed to cool and then subjected to various tests. In addition, adhesion,
The corrosion resistance and the interlayer resistance were evaluated for the product plate after being left to cool and for the annealed plate after strain relief annealing at 750 ° C. for 2 hours in a nitrogen atmosphere.

[Aqueous Dispersion Composition] (a) Aqueous Dispersion of Ionomer of Self-Emulsifying Ethylene-Unsaturated Carboxylic Acid-Unsaturated Carboxylic Acid Metal Salt Copolymer: “Cemipearl S-100”, Mitsui Petrochemical Industry Co., Ltd. ]
Ion-exchanged water was added to (ethylene-methacrylic acid-Na methacrylic acid salt copolymer, minimum film forming temperature 90 ° C.) to adjust the solid content concentration to 5% by weight. (B) Ion-exchanged water was added to colloidal silica having an average particle diameter of 50 nm to adjust the solid content concentration to 5% by weight. Further, sodium hydroxide was added to adjust the pH to the same as (a) (about 10). (C) Ion-exchanged water was added to N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, which was diluted 50 times and dissolved. (D) Add ion-exchanged water to Na ₂ MoO ₄ .2H ₂ O and add 50
Diluted and dissolved twice. The respective aqueous liquids of (a) / (b) / (c) / (d) are mixed at a ratio of 100/100/5/10 parts by weight in terms of solid content,
An aqueous composition was obtained. The details of various performance evaluation methods are as follows. Table 2 shows the results of various performance evaluations.

(Corrosion resistance [salt spray test]) 35 ° C., 5%
The evaluation was performed from the time when the area ratio of red rust generation was 10% or more under the condition of the NaCl solution. ◎: 5 hours or more ○: 3 to less than 5 hours △: 1 to less than 3 hours ×: less than 1 hour

(Corrosion Resistance [Boiling Steam Exposure Test]) Ion-exchanged water in a beaker was boiled, an electromagnetic steel sheet with an insulating coating was placed thereon, and the state of the coating after 30 minutes was evaluated. ◎: No change ○: Part of the film is discolored △: Almost the entire surface of the film is discolored ×: Rust is generated

(Corrosion resistance [wetting test]) Evaluation was made from the area ratio of red rust after exposure for 48 hours under high temperature and high humidity conditions of 50 ° C. and 98% relative humidity. A: Less than 5% O: 5 to 20% B: 20 to 50% X: Over 50%

(Solvent resistance) The surface of the insulating coating was rubbed 5 times with absorbent cotton soaked with hexane, xylene, methanol, ethanol and acetone to evaluate the dissolution of the coating and the presence or absence of scratches. ◎: No change in all solvents ○: Scratches occurred in any one solvent Δ: Scratches occurred in more than one solvent ×: Film dissolved in any solvent

(Adhesion) The adhesion was evaluated from the film peeling rate after the 180 ° bending back test at 20 mmφ. ⊚: No change ◯: Peeling less than 20% △: Peeling 20 to 40% X: Peeling 40% to full peeling

(TIG Weldability) Welding was carried out under the following conditions and evaluated from the maximum welding speed at which blowholes were not generated. Electrode: Th-W 2.6 mmφ Applied pressure: 100 kg / cm ² Current: 120 A Shield gas: Ar 6 L / min ◎: 600 mm / min ○: 400 to 600 mm / min Δ: 300 to 400 mm / min ×: Less than 300 mm / min

(Interlayer Resistance) The interlayer resistance value was measured according to JIS method 2. ○: 5 Ωcm ² / sheet or more △: 3 to 5 Ωcm ² / sheet ×: less than 3 Ωcm ² / sheet

(Punching property) With a 15 mmφ steel die, evaluation was made from the number of punches until the burr height reached 50 μm. ◎: Over 500,000 times ○: 300,000 to 500,000 times △: 100,000 to 300,000 times ×: Less than 100,000 times

(Blocking resistance) Magnetic steel with insulating coating
2 cm for 2 plates²200kg / c, pasted in the area of
m ²Under a load of 80 ° C for 48 hours
Then, it was left to cool and evaluated by measuring the shear adhesive strength. ◎: No sticking at all ○: Shear adhesive strength 10 kg / cm²Less than Δ: Shear adhesive strength 10 to 30 kg / cm² X: Shear adhesive strength 30 kg / cm²Super

(Seizure resistance) Ten sheets of 50 mm square steel sheets were stacked and annealed at 750 ° C. for 2 hours in a nitrogen atmosphere while applying a load (200 g / cm ² ) and then a weight of 500 g was dropped on the steel sheet to obtain 5 The drop height when dividing was investigated. ◎: 10 cm or less ○: 10 to less than 20 cm △: 20 to 40 cm ×: more than 40 cm

[0077] (Inventive Example 1-2～1- 11, Comparative Examples 1-1 to 1-7) component of the insulating coating, these mixing ratios, the adhesion amount of the insulating coating, and baking temperatures as shown in Table 1 In the same manner as in Inventive Example 1 except that the above was changed to, an insulating coated electromagnetic steel sheet was produced and various evaluations were performed. The evaluation results are shown in Table 2. As is clear from Table 2, all of the electrical steel sheets with an insulating coating according to the present invention have excellent corrosion resistance and solvent resistance, and also have good adhesion, weldability, interlayer resistance, punchability, blocking resistance, and baking resistance. It is also excellent in sex.

(Example 2) (Invention Example 2-1) A silane coupling agent (c ₁ ) diluted with an aqueous medium shown below was formed on the surface of an electromagnetic steel sheet having a surface temperature of 60 ° C. and a thickness of 0.5 mm. Was applied using a roll coater. The coating amount was 0.015 g / m ² in terms of solid content (undiluted content) of the silane coupling agent. Continuing,
A silane coupling agent (c ₂ ), an aqueous resin dispersion (a) and colloidal silica (b) shown below were added to (c ₂ ) /
The aqueous composition mixed at a ratio of (a) / (b) = 4/100/100 parts by weight was applied using a roll coater.
Then, hot-air drying and baking were performed at a steel plate reaching temperature of 120 ° C. The amount of insulating coating after baking is 0.5 g / m
^{Was 2} . The obtained insulating coated steel sheet was allowed to cool and then subjected to various tests. For adhesion, corrosion resistance, and interlayer resistance, leave the product plate after cooling in a nitrogen atmosphere at 75
The annealed plate after strain relief annealing at 0 ° C. for 2 hours was evaluated.

Ion-exchanged water was added to (c ₁ ) and (c ₂ ) N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, and the mixture was diluted 50 times and dissolved. (A) Aqueous dispersion of ionomer of self-emulsifying ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer: "Cemipearl S-100" manufactured by Mitsui Petrochemical Co., Ltd.
Ion-exchanged water was added to (ethylene-methacrylic acid-Na methacrylic acid salt copolymer, minimum film forming temperature 90 ° C.) to adjust the solid content concentration to 5% by weight. (B) Ion-exchanged water was added to colloidal silica having an average particle diameter of 60 nm to adjust the solid content concentration to 5% by weight. Further, sodium hydroxide was added to adjust the pH to the same as (c ₂ ) (about 10). The details of various performance evaluation methods are as described in Example 1 above. Table 4 shows the results of various performance evaluations.

(Invention Examples 2-2 to 2-3 and Comparative Examples 2-1 to 2-8) Table 3 shows the constituent components of the insulating coating, their mixing ratio, the amount of the insulating coating deposited, and the baking temperature. In the same manner as in Example 2-1 except that the above was changed to, an insulating coated electromagnetic steel sheet was produced and various evaluations were performed. The evaluation results are shown in Table 4. Table 4
As is clear from the above, the insulating coated electromagnetic steel sheets according to the present invention are all excellent in corrosion resistance, solvent resistance, and adhesion, weldability, interlayer resistance, punchability, blocking resistance, and seizure resistance. Is also excellent.

Example 3 (Invention Example 3-1) The aqueous composition (A) was spray coated on the surface of an electromagnetic steel sheet having a surface temperature of 70 ° C. and a sheet thickness of 0.5 mm,
After the aqueous medium was naturally dried, the aqueous composition (B) was applied to the same surface by using a roll coater. Then, hot-air drying was performed at a steel plate arrival temperature of 150 ° C. and a heating time of 10 seconds. The amount of the insulating coating deposited after drying was 0.6 g / m ² . In addition, the amount of solid content adhered after coating the aqueous composition (A) was 0.3 g / m ² . The obtained insulating coated steel sheet was allowed to cool and then subjected to various tests. Adhesion, corrosion resistance and interlayer resistance were evaluated for the product plate after cooling and for the annealed plate after strain relief annealing at 750 ° C. for 2 hours in a nitrogen atmosphere.

[Aqueous Composition A] Passivating agent (d): Na ₂ MoO ₄ .2H ₂ O Aqueous inorganic substance (b ₁ ): Ion exchange containing 3% by weight of colloidal silica having an average particle diameter of 47 nm and isopropanol. Water was mixed to adjust the solid content concentration to 5% by weight and the solid content mixing weight ratio to (d) / (b ₁ ) = 10/100.

[Aqueous Composition B] Silane coupling agent (c): N-β (aminoethyl)
γ-Aminopropylmethyldimethoxysilane aqueous resin (a): an aqueous dispersion of ethylene-methacrylic acid-Na-methacrylic acid salt copolymer (Mitsui Petrochemical Co., Ltd. “Chempearl S-100” film forming temperature 90 ° C.) and 3 parts of isopropanol Ion-exchanged water contained in an amount of 10% by weight is mixed, the solid content concentration is 10% by weight, and the solid content mixing weight ratio is (c) / (a).
= 10/100. The details of various performance evaluation methods are as follows. Table 6 shows the results of various performance evaluations.

(Corrosion resistance [salt spray test]) 35 ° C., 5%
The evaluation was performed from the time when the area ratio of red rust generation was 10% or more under the condition of the NaCl solution. ◎: 15 hours or more ○: 7 to less than 15 hours △: 3 to less than 7 hours ×: less than 3 hours

(Corrosion resistance [boiling steam exposure test]) Ion-exchanged water in a beaker was boiled, an electromagnetic steel sheet with an insulating coating was placed thereon, and the state of the coating after 30 minutes was evaluated. ◎: No change ○: Part of the film is discolored △: Almost the entire surface of the film is discolored ×: Rust is generated

(Corrosion resistance [wet test]) Evaluation was made from the area ratio of red rust after exposure for 48 hours under high temperature and high humidity conditions of 50 ° C. and relative humidity of 98%. ⊚: No rusting ○: Less than 20% △: 20-50% ×: Over 50%

(Solvent resistance) The surface of the insulating coating was rubbed 5 times with absorbent cotton soaked in hexane, xylene, methanol, ethanol and acetone to evaluate the dissolution of the coating and the presence of scratches. ◎: No change in all solvents ○: Scratches occurred in any one solvent Δ: Scratches occurred in more than one solvent ×: Film dissolved in any solvent

(Adhesion) Evaluation was made from the film peeling rate after the 180 ° bending back test at 20 mmφ. ⊚: No change ◯: Peeling less than 20% △: Peeling 20 to 40% X: Peeling 40% to full peeling

(TIG Weldability) Welding was performed under the following conditions, and the maximum welding speed at which blowholes did not occur was evaluated. Electrode: Th-W 2.6 mmφ Applied pressure: 100 kg / cm ² Current: 120 A Shield gas: Ar 6 L / min ◎: 600 mm / min ○: 400 to 600 mm / min Δ: 300 to 400 mm / min ×: Less than 300 mm / min

(Interlayer Resistance) The interlayer resistance value was measured according to JIS method 2. ○: 5 Ωcm ² / sheet or more △: 3 to 5 Ωcm ² / sheet ×: less than 3 Ωcm ² / sheet

(Punching property) With a 15 mmφ steel die, evaluation was made from the number of punches until the burr height reached 50 μm. ◎: Over 500,000 times ○: 300,000 to 500,000 times △: 100,000 to 300,000 times ×: Less than 100,000 times

(Blocking resistance) Magnetic steel with insulating coating
2 cm for 2 plates²200kg / c, pasted in the area of
m ²Under a load of 80 ° C for 48 hours
Then, it was left to cool and evaluated by measuring the shear adhesive strength. ◎: No sticking at all ○: Shear adhesive strength 10 kg / cm²Less than Δ: Shear adhesive strength 10 to 30 kg / cm² X: Shear adhesive strength 30 kg / cm²Super

(Seizure resistance) Ten sheets of 50 mm square steel sheets were stacked and annealed at 750 ° C. for 2 hours in a nitrogen atmosphere while applying a load (200 g / cm ² ), and then a weight of 500 g was dropped on the steel sheet. The drop height when dividing was investigated. ◎: 10 cm or less ○: 10 to less than 20 cm △: 20 to 40 cm ×: more than 40 cm

[0094] components of the (invention examples 3-1～3- 8, Comparative Example 3-1～3-11) the aqueous composition (A) (B), the adhesion amount of mixing ratio, the insulating coating, the baking temperature The same procedure as in Inventive Example 1 was carried out except that the above items were changed as shown in Table 5, and an electromagnetic steel sheet with an insulating coating was produced and various evaluations were performed. Table 6 shows the evaluation results.
Shown in. As is clear from Table 6, the insulating coated electromagnetic steel sheets according to the present invention show excellent corrosion resistance before and after annealing, and also have solvent resistance, adhesiveness, weldability, interlayer resistance, punching resistance, and corrosion resistance. Excellent blocking and seizure resistance.

[0095]

[Table 1]

[0096]

[Table 2]

[0097]

[Table 3]

[0098]

[Table 4]

[0099]

[Table 5]

[0100]

[Table 6]

[0101]

[Table 7]

[0102]

[Table 8]

[0103]

[Table 9]

[0104]

[Table 10]

[0105]

[Table 11]

[0106]

[Table 12]

[0107]

[Table 13]

[0108]

[Table 14]

[0109]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it can be manufactured by low-temperature baking, strain relief annealing is possible, particularly excellent in corrosion resistance before and after annealing, and in addition, it is necessary as an insulating coating for electromagnetic steel sheets. Since it has excellent performance, it can be widely and widely used as a magnetic steel sheet for applications such as motors and transformers.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08L 23/26 C08L 23/26 (72) Inventor Yuka Komori 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Works, Ltd. Technical Research Institute ( 56) References JP-A-54-31598 (JP, A) JP-A 1-270976 (JP, A) JP-A 52-90435 (JP, A) JP-A 62-50483 (JP, A) JP-A Flat 2-38582 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 15/08 B05D ⁷ /14-7/24

Claims (15)

(57) [Claims] 1. (a) Ethylene-containing resin having a melting point of more than 60 ° C.
Saturated carboxylic acid copolymer (b) containing silica (a) and (b), and further (c) silane coupling agent (d) passivating agent (excluding chromium compound) (c) and (d) Containing at least one selected from the group consisting of (a) / (b) / (c + d) and having a solid content weight ratio of 1
00/20 to 500 / 0.1 to 50 and does not contain an emulsifier.
No insulating coating is possible stress relief annealing, characterized in that formed by dry coated on the surface of the electrical steel sheet and corrosion resistance, insulation coating with an electromagnetic steel sheet with excellent solvent resistance. 2. The ethylene-unsaturated carboxylic acid copolymer
Is a self-emulsifying ethylene-unsaturated carboxylic acid copolymer
The strain relief annealing according to claim 1 is possible, and corrosion resistance and melting resistance
Magnetic steel sheet with an insulating coating that has excellent chemical properties. 3. The strain relief annealing according to claim 1 or 2 , wherein the ethylene-unsaturated carboxylic acid copolymer is an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer. An electrical steel sheet with an insulating coating that has excellent corrosion resistance and solvent resistance. 4. The passivating agent is Na ₂ MoO ₄ , NaNO ₂ , Na ₂ W
It is at least one Na-based passivating agent selected from O ₄ , CH ₃ COONa, and C ₆ H ₅ COONa, and is capable of strain relief annealing, corrosion resistance, and solvent resistance. Magnetic steel sheet with an insulating coating that excels in performance. 5. The amount of the insulating film deposited is 0.05 to dry weight.
It is 4 g / m < ² >, and the electrical steel sheet with an insulating film which is capable of strain relief annealing according to any one of claims 1 to 4 and is excellent in corrosion resistance and solvent resistance. 6. (a) Ethylene-containing resin having a melting point of more than 60 ° C.
An aqueous solution or dispersion of a saturated carboxylic acid copolymer , (b) colloidal silica, (a) and (b), and (c) silane coupling agent (d) passivating agent (chromium compound Excluding) At least one selected from (c) and (d) is included, and the solid content weight ratio of (a) / (b) / (c + d) is 1
00/20 to 500 / 0.1 to 50 and does not contain an emulsifier.
The amount of adhesion of an aqueous composition having no dryness is 0.05 to 4
It is applied to the surface of the electrical steel sheet so that it becomes g / m ^2, and 80 to 2
A method for forming an insulating coating on a magnetic steel sheet, which is capable of strain relief annealing and is excellent in corrosion resistance and solvent resistance, which comprises drying an aqueous medium at a steel sheet arrival temperature of 50 ° C. 7. The ethylene-unsaturated carboxylic acid copolymer
The aqueous dispersion of is a self-emulsifying ethylene-unsaturated carvone.
The strain relief according to claim 6, which is an aqueous dispersion of an acid copolymer.
Electromagnetic insulation film that can be annealed and has excellent corrosion resistance and solvent resistance
Forming method on steel sheet. Wherein said ethylene - aqueous dispersion of an unsaturated carboxylic acid copolymer, ethylene - unsaturated carboxylic acid - claim 6 or 7 which is an aqueous dispersion of an ionomer of an unsaturated carboxylic acid metal salt copolymer A method for forming an insulating coating on a magnetic steel sheet, which is capable of strain relief annealing and is excellent in corrosion resistance and solvent resistance. 9. The passivating agent is Na ₂ MoO ₄ , NaNO ₂ , Na ₂ W.
O _4, one of the CH ₃ COONa, where and C ₆ H ₅ is at least one of Na-based passivating agent selected from COONa claims 6-8
Method of forming the stress relief annealing is possible corrosion resistance, electrical steel sheet of the insulating coating which is excellent in solvent resistance according to any. 10. A (c ₁ ) silane coupling agent diluted with an aqueous medium is applied to the surface of an electromagnetic steel sheet, and subsequently (c ₂ ) silane coupling agent (a) ethylene having a melting point of more than 60 ° C. Unsaturated carvone
Aqueous solution or aqueous dispersion of acid copolymer (b) containing colloidal silica (c ₂ ), (a) and (b) and containing an emulsifier
A non- aqueous composition is (c ₁ ) / (c ₂ ) / (a) / (b)
The undiluted weight ratio of 0.1 to 50/0 to 50 (wherein the total amount of (c ₁ ) + (c ₂ ) is 0.1 to 50 parts by weight) / 100
/ 20 to 500, the amount of adhesion after drying is 0.05 to 4 g / m
^{2. A} method for forming an insulating coating on a magnetic steel sheet with an insulating coating, which is capable of strain relief annealing and is excellent in corrosion resistance, characterized in that it is applied so as to become ^2, and the aqueous medium is dried and removed at a steel sheet reaching temperature of 80 to 250 ° C. 11. The ethylene-unsaturated carboxylic acid copolymerization
The body is a self-emulsifying ethylene-unsaturated carboxylic acid copolymer
The strain relief annealing according to claim 10 which is an aqueous dispersion of
Of insulating coating with excellent corrosion resistance and solvent resistance
Forming method. 12. The ethylene-unsaturated carboxylic acid copolymerization
The product is an aqueous dispersion of an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer.
The method for forming an insulating coating on an electromagnetic steel sheet with an insulating coating, which is capable of strain relief annealing and is excellent in corrosion resistance according to 10 or 11 . 13. An aqueous composition (b ₁ ) comprising a passivating agent (excluding chromium compounds) (d), an aqueous inorganic substance (b ₁ ) selected from colloidal silica and an aqueous solution of an alkali silicate on the surface of an electromagnetic steel sheet. A) is applied, and then the silane coupling agent (c) and the melting point are applied to the same applied surface.
It contains an emulsifier consisting of an aqueous solution or dispersion (a) of an ethylene-unsaturated carboxylic acid copolymer having a temperature higher than 60 ° C.
The amount of the insulating coating after drying the aqueous composition (B) which does not have 0.05 to 4 g / m ² , (d) / (b ₁ ) / (c) /
The solid content weight ratio of (a) is (0.1-50) / (20-5).
00) / (0.1-50) / 100, and is capable of strain relief annealing characterized by drying an aqueous medium at a steel plate reaching temperature of 80 to 250 ° C. and corrosion resistance after annealing. A method for forming an insulating coating on a magnetic steel sheet with an insulating coating that is excellent in heat resistance. 14. The ethylene-unsaturated carboxylic acid copolymerization
The body is an aqueous dispersion of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metal salt copolymer, and strain-relief annealing is possible according to claim 13, and an electrical steel sheet with an insulating coating having excellent corrosion resistance after annealing. Method for forming an insulating film. 15. The passivating agent (d) is Na ₂ MoO ₄ , NaNO ₂ ,
_{Na 2 WO 4, CH 3 COONa} , and C ₆ H ₅ is at least one of Na-based passivation agent selected from COONa claims 13 or
14. The method for forming an insulating coating on an electromagnetic steel sheet with an insulating coating, which enables the strain relief annealing according to 14 and has excellent corrosion resistance after annealing.