KR19990049358A - Electronic steel sheet capable of stress relief annealing and excellent solvent resistance and manufacturing method thereof - Google Patents

Abstract

There is provided an electrical steel sheet having an insulating film which can be produced by baking at low temperature, is capable of stress relief annealing, is excellent in solvent resistance, and contains little chromium component harmful to the environment. The electrical steel sheet has an insulating film containing a resin and an inorganic colloid which is silica, alumina or alumina-containing silica.

Description

Electronic steel sheet capable of stress relief annealing and excellent solvent resistance and method of manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical steel sheet having an insulating coating, and in particular, does not contain harmful compounds such as hexavalent chromium and can be produced by low temperature baking, and stress relief annealing is possible. The invention also relates to an electrical steel sheet having a good insulating coating and a method of manufacturing the same.

Insulation coatings of electrical steel sheets used in materials such as motors and transformers require not only interlayer resistance, but also various characteristics from the viewpoint of convenience and use in processing molding and storage. Required properties include punching, TIG weldability, film adhesion, corrosion resistance, solvent resistance, heat resistance, anti-blocking, anti-tension pat property, and corrosion resistance or stress after annealing stress relief. Sticking property, etc. are mentioned.

In order to improve magnetic properties after punching, an electrical steel sheet is often subjected to stress relief annealing at about 750 to 850 ° C., so that the insulating film is often required to withstand this stress relief annealing. Therefore, development of various insulating films is performed according to the electronic steel plate used variously.

But in general, the insulating film is

무기 Mineral coating that emphasizes weldability and heat resistance and can withstand stress relief annealing

수지 Resin-containing semi-organic coatings aimed at achieving both punchability and weldability and withstanding stress relief annealing

유기 Organic coatings for which stress relief annealing is not possible in special applications

It can be divided into three species. Among them, a film containing ㉠ and 무기 inorganic materials that can withstand stress relief annealing as a general purpose product. In particular, the chromate-based insulating film containing an organic resin can be formed by a process of one coat one baking, and is widely used because of its excellent punchability compared to the inorganic insulating film.

The manufacturing method of the electronic steel plate which has this chromate type insulation coating is disclosed by Unexamined-Japanese-Patent No. 60-36476, for example. In other words, in a dichromate-based aqueous solution containing at least one divalent metal, a vinyl acetate / veova (VEOVA: Vinyl Ester Of Versatic Acid) ratio as an organic resin relative to 100 parts by weight of CrO ₃ in the aqueous solution The process liquid which mix | blended 5 to 120 weight part of resin emulsion which becomes a ratio of 90/10-40/60 by resin solid content, and the organic reducing agent in the ratio of 10 to 60 weight part was apply | coated to the steel disk surface, and the conventional method Baking in accordance with.

The electrical steel sheet with this insulating film satisfies various performances including corrosion resistance and solvent resistance. However, the chromate-based coating needs to be baked at a relatively high temperature in order to reduce and insolubilize hexavalent chromium to trivalent chromium. However, baking at a high temperature is costly due to an increase in energy consumption during manufacture or a decrease in the speed of insulating coating. Causes an increase. In the case of the semi-organic film containing the resin, the resin may be thermally deteriorated at the time of baking at a high temperature, thereby impairing the original performance of the resin. In addition, hexavalent chromium is concerned about environmental pollution, and there is a problem in that the exhaust treatment and waste liquid treatment are expensive.

In addition, as an insulating coating other than chromate, a semi-organic insulating coating containing a resin based on phosphate is also studied. However, phosphate needs to be baked at a high temperature after coating in order to proceed with dehydration and insolubilize, and has the same problem as the chromate coating.

As an insulating film which can be baked at a relatively low temperature, a method is known in which a film is formed before temper rolling using latent heat during continuous annealing to give an anti-baking film during stress relief annealing. For example, Japanese Patent Application Laid-Open No. 59-21927 discloses a method of rough rolling by applying an aqueous solution containing an inorganic colloidal substance as a main component and adding a water-soluble or emulsion type resin as it is. According to this method, the inorganic colloidal substance can surely be baked at a low temperature compared with the chromate or phosphate coating. That is, since chromate-based and phosphate-based prevents stickiness, it is necessary to proceed with a film forming reaction for making the water-insoluble material water insoluble, but the inorganic colloidal material does not need to be, and silica is dehydrated at the lowest temperature. It is advantageous at the time of low-temperature baking because this ends.

In addition, as an example of a semi-organic insulating film which can be baked at a relatively low temperature and does not contain chromic acid, Japanese Patent Application Laid-Open No. 54-31598 discloses a treatment liquid composed of silica hydrosol and an organic material. The electromagnetic steel plate which has a heat resistant and baking resistant film which has a silica gel containing an organic substance as a main component by apply | coating to a surface and heating at the temperature of 100-350 degreeC, and its surface treatment method are disclosed.

However, the above-described insulating film of the prior art is effective in preventing sticking during temper rolling and stress relief annealing, but has a problem in that solvent resistance is poor. There are many opportunities for contact with organic solvents such as cleaning with solvents, contact with refrigerants (freons, etc.), and various oils (punching oil, insulating oil, refrigeration oil). It becomes necessary.

Moreover, in the said prior art, there existed a problem that the dispersion | variation in corrosion resistance is large and a case where a good case and a bad case generate | occur | produce.

Specifically, in Japanese Patent Application Laid-Open No. 54-31598, as can be seen from the examples, the comparative examples containing chromate do not rust in the wet test, whereas all of the inventive examples have rust. In Japanese Patent Publication No. 59-21927, since there is no description on corrosion resistance, etc., the performance of an electromagnetic steel sheet having an insulating coating made of acetbi-acrylic copolymer resin and various inorganic colloidal materials, which are used only in the examples, was investigated. The film performance, such as solvent resistance, did not satisfy the performance of the chromate-based general purpose coat required by the manufacturer of the electronic steel sheet.

In addition, there is a problem in the conventional art that the boiling water vapor exposing property is inferior. The electromagnetic steel sheet may be exposed to high temperature and high humidity conditions, such as a case where a high temperature and high humidity condition is transported by shipping, and a motor may be heated to become a high temperature and high humidity condition. In addition to defrosting, boiling steam exposure is often required.

Inorganic colloidal silica is excellent in heat resistance and extremely effective in preventing baking of steel sheets, as seen in the prior art, but silica alone has poor adhesion to steel sheets and poor lubricity and poor punching properties. In addition, there was a drawback that the coating was weak and the rust easily occurred. On the other hand, an organic resin has the characteristics completely opposite to the inorganic colloidal silica which is excellent in punching property and adhesiveness but inferior in heat resistance. Thus, an insulating film of an organic-inorganic mixed composition having both advantages has been developed, and as described above, it cannot be said that the film has sufficient various coating properties required for an electromagnetic steel sheet.

It is a first object of the present invention to provide an electronic steel sheet having an insulating film which can be manufactured by low temperature baking, can be stress relief annealed, has excellent solvent resistance, and contains substantially no chromium component harmful to the environment. .

It is a second object of the present invention to provide an electronic steel sheet having an insulating film which can be manufactured by low temperature baking, capable of stress relief annealing, and also has excellent corrosion resistance.

It is a third object of the present invention to provide an electronic steel sheet having an insulating film which can be produced by low temperature baking, is capable of stress relief annealing, and also has excellent boiling vapor exposing properties.

Further, a fourth object of the present invention is to provide a method for producing a non-oriented electrical steel sheet capable of low temperature baking, stress relief annealing, and excellent punching property and baking resistance after annealing.

In addition, the present invention provides an electronic steel sheet having an insulating coating excellent in various properties necessary for various functions of the electronic steel sheet, that is, adhesiveness, sticking property, film forming property, weldability and the like, while achieving the above various objects.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the corrosion resistance and solvent resistance of the product board (before annealing) with respect to the surface area ratio of the colloidal silica which occupies in a process liquid and the surface area which an aqueous acid resin occupies.

Fig. 2 shows the influence of silica on punching property.

3 shows the effect of silica on the anti-sticking property.

4 is a diagram showing the effect of the amount of coating (coating) on the film adhesion of the product plate.

Fig. 5 shows the effect of coating amount on the film adhesion of the annealing plate.

6 shows the effect of coating amount on punchability.

7 shows the effect of coating amount on sticking properties.

(1) The present invention provides an electrical steel sheet capable of stress relief annealing and having excellent solvent resistance, which has an insulating film containing a resin and an inorganic colloid which is silica, alumina or alumina-containing silica.

(2) The present invention further provides a method of manufacturing the electromagnetic steel sheet described in (1) above by baking an insulating film at a low temperature, that is, at a steel sheet temperature of 50 to 250 ° C.

(3) In the present invention, the inorganic colloid in the insulating film described in the above ① is silica, and the insulating film is M ₂ O (M) with respect to silica having 100 parts by weight in terms of SiO ₂ of at least one alkali metal selected from Li, Na, and K. An alkali steel sheet capable of providing stress relief annealing containing 0.1 to 5 parts by weight in terms of alkali metal) and having excellent solvent resistance.

(4) The present invention relates to a resin having Cl and S in the insulating film described in the above ③, wherein Cl is 0.005 parts by weight or less, S is 0.05 parts by weight or less, and silica is 100 parts by weight with respect to silica having 100 parts by weight in terms of SiO ₂ . It provides an electronic steel sheet capable of stress relief annealing, which is 3 to 300 parts by weight in terms of SiO ₂ , and excellent in solvent resistance.

(5) The present invention provides an electronic steel sheet capable of stress relief annealing and having excellent solvent resistance, wherein the glass potential of the resin in the insulating film described above is 30 to 150 ° C.

(6) In the method for producing the electromagnetic steel sheet according to the above (3), 30 to 300 parts by weight of the colloidal silica solid content is added to 100 parts by weight of the aqueous dispersion resin solid content, and the colloidal silica solid content particles occupy The surface area (specific surface area × solid content weight) is applied to the surface of the steel sheet by applying a coating liquid containing water adjusted to 0.2 to 10 times as a solvent to the surface area (specific surface area × solid content weight) occupied by the water-based resin solid particles. The present invention provides a method for producing an electrical steel sheet capable of stress relief annealing and excellent solvent resistance, and an electromagnetic steel sheet obtainable by the manufacturing method.

(7) The present invention provides an electronic steel sheet capable of stress relief annealing and having excellent solvent resistance, wherein the inorganic colloid in the insulating film described in the above (1) is alumina, and the resin has a glass potential of 30 to 150 ° C.

(8) The present invention provides an electronic steel sheet capable of stress relief annealing and having excellent solvent resistance, wherein the inorganic colloid in the insulating film described in (1) above is alumina-containing silica, and the glass transition point of the resin is 30 to 150 ° C.

(9) In the above (7) or (8), it is preferable to contain an organic acid as the stabilizer of the alumina in the insulating coating, and the alumina or the alumina-containing silica is preferably 3 to 300 parts by weight in terms of Al ₂ O ₃ + SiO _2. Do. In the alumina of the insulating film with respect to 100 parts by weight of silica in terms of SiO _2, preferably 0.01 ~ 500 parts by weight as Al ₂ O ₃ conversion.

⑩ And it is preferable that the insulation coating amount of the electromagnetic steel sheet of this invention is 0.05-4 g / m <2>.

EMBODIMENT OF THE INVENTION Hereinafter, the electromagnetic steel plate (henceforth "electromagnetic steel sheet of this invention") with the insulating film of this invention is demonstrated in detail.

1. Steel Plate

The steel original plate of the electromagnetic steel sheet of the present invention is not particularly limited, and various compositions can be used, and ordinary steel having almost no Si can be used as well as ordinary electric iron plates.

2. Resin

The solvent resistance at the time of low-temperature baking of the resin / inorganic colloid blend system was examined in detail, and it was found that the solvent resistance was particularly strong in the resin alone. That is, in the case of low-temperature baking of about 50-200 degreeC, it turned out that the crosslinking reaction of resin by a crosslinking agent brand is hard to advance. Therefore, it is thought that it is important to obtain the solvent resistance of the resin alone, and as a result of repeated examinations, it was found that the solvent resistance was excellent when the glass transition point of the resin was 30 ° C or higher. Moreover, the film formation property at the time of low temperature baking was able to be ensured by making resin glass transition point into 150 degrees C or less.

Therefore, resin to mix | blend in a process liquid is aqueous resin (emulsion, dispersion, water soluble), and resin of the monomer composition whose glass transition point is 30-150 degreeC, Preferably it is 40-130 degreeC is used. If the resin glass transition point is less than 30 ° C., solvent resistance is insufficient, and if the resin glass transition point is more than 150 ° C., the film formation property at the time of low temperature baking is inferior. Therefore, it is preferable that the glass transition point of resin is 30-150 degreeC.

The resin composition used herein is not particularly limited, but for example, acrylic resin, alkyd resin, polyolefin resin, styrene resin, vinyl acetate resin, epoxy resin, phenol resin, urethane resin, melamine resin, polyester It is preferable to take the monomer composition which 1 type or 2 types of resin in can be applied suitably, and the glass transition point of resin will be 30-150 degreeC. The glass transition point of the resin is a property of resin oils constantly depending on the monomer composition. Usually, resin often combines several types of monomers.

Resin suitable for the present invention can be applied to any resin composition when the glass transition point is 30 to 150 ℃. In the case where the glass transition point is not clear, the softening point may be 30 to 150 ° C. Since the resin varies greatly with respect to the glass transition point, it is preferable that the glass transition point is higher than the operating environment temperature. Various methods can be used to measure the glass transition point, such as DSC (differential scanning calorimetry), TMA (thermomechanical analysis), thermal expansion, etc., but are not particularly limited. This can be confirmed by using a change method. In addition, since the glass transition point of a copolymer can also be calculated, what is necessary is just to calculate from a composition when it is difficult to measure.

3. inorganic colloid

In the present invention, the inorganic colloid consists of at least one of silica, alumina and alumina-containing silica.

3. 1 silica

The silica, which is an insulating coating component of the electromagnetic steel sheet of the present invention, is not particularly limited, and may be prepared by any manufacturing method as long as it is dispersed in water, and various kinds of colloidal silica, vapor phase silica, agglomerated silica, and the like. Can be used.

The silica content of the insulating film in the are, it is preferred that the silica ratio of 3-300 parts by weight as SiO ₂ in terms of parts for 100 parts by weight of resin. If the silica content is less than 3 parts by weight, the resin powder will thermally decompose upon stress relief annealing, so there is little film residue, and the performance, sticking resistance and corrosion resistance during annealing are insufficient. Moreover, when silica exceeds 300 weight part, punching property and adhesiveness will fall.

3. 1.1 alkali metal

The inventors found that alkali metal addition is effective for improving the solvent resistance of the resin / silica-based insulating film.

Since the solvent resistance of silica was excellent, it was thought that solvent resistance can be improved further by obtaining the solvent resistance of resin itself and promoting crosslinking of resin and silica. That is, to obtain the solvent resistance of the resin itself, it is effective to obtain the glass potential point of the resin as described above, and exhibits good performance at the glass potential point of 30 ° C. or higher, but the degree is light depending on the type of solvent in the vicinity of 30 ° C. There is a slight infringement, and in this case, containing alkali metal in silica shows superior solvent resistance than the resin alone. Although it is not certain about this mechanism, it can also be considered that alkali metal acts as a metal crosslinking agent which promotes crosslinking of silica and resin.

The alkali metal content in the insulating film is 0.1 to 5 parts by weight in terms of M ₂ O (M: alkali metal, Li ₂ O, Na ₂ O, K ₂ O) based on 100 parts by weight of silica in terms of SiO ₂ , preferably It is 0.1-3 weight part. If the alkali metal is less than 0.1 part by weight, solvent resistance is insufficient, and even if it exceeds 5 parts by weight, further solvent resistance improvement cannot be expected. Moreover, especially when Na and K are added excessively as alkali metal, sodium silicate, potassium silicate, etc. may arise in the surface of a silica, and a problem may arise in water resistance. In the case of colloidal silica, a stable region of pH exists. Therefore, when colloidal silica is used, when the amount of alkali metal is small and becomes a neutral instable region, pH adjustment may be performed by adding ammonia or the like. Moreover, you may post-add an alkali metal to the coating liquid which mix | blended resin and silica.

3.2 low Cl, S

The present inventors examined the influence factors on the various film performances of the resin / silica system in detail and found that the corrosion resistance after the stress relief annealing of the steel sheet and the sheet was strongly affected by the type of silica used. In particular, it was found that the smaller the amount of anions of Cl ⁻ and SO ₄ ^2- in silica, the better. That is, it was found that the corrosion resistance after annealing of the electromagnetic steel sheet and the electromagnetic steel sheet can be improved by setting the Cl and S amounts to the specific amount of SiO _{2 in the} film to be a specific amount or less.

The silica used in the present invention is previously removed from anions such as Cl ⁻ , SO ₄ ² -by ion exchange, etc., and pure water is used as water and dilution water during resin synthesis. The amount of Cl and S is preferably controlled to be 0.005 parts by weight or less and 0.05 parts by weight or less with respect to 100 parts by weight of SiO ₂ , respectively. When the amount of Cl and S in the insulating film exceeds the above-mentioned amount, the corrosion resistance after annealing of the electromagnetic steel sheet and the electromagnetic steel sheet is lowered.

3. 1.3 surface area

The present inventors also examined in detail the factors affecting the corrosion resistance of the resin silica mixed film. As a result, the corrosion resistance greatly changes depending on the coating structure. In particular, when the resin is an aqueous acid resin having a particle size, the coating structure occupies a surface area occupied by particles of organic resin and colloidal silica composed of fine particles dispersed in the treatment liquid. Newly discovered that it is related to and came to complete this invention.

The dispersion medium is basically water, and even if a surfactant or other dispersing agent for preventing agglomeration of the resin is added, there is no problem in practical use. As the types of aqueous resins, three types of water soluble type, water soluble type, disperse type, and emulsion type are known, but any type can be used. Resin solids are 10 to 50 weight% concentration.

However, in the case where the resin to be blended with silica is an aqueous acid resin having a particle size, the specific surface area of the resin particles dispersed in these waters is in a suitable range in consideration of the change in the film structure due to the colloidal silica mixing described later. The surface area is about 40-600 m <2> / g.

The resin composition is not particularly limited, and one or two or more resins of alkyd, phenyl, melamine, polyester, vinyl acetate resin, epoxy resin, polyolefin resin, styrene resin, acrylic resin and urethane resin can be applied. .

Another component of the insulating coating of the present invention is silica. The form of silica is not special, and colloidal silica, gas phase silica, and the like are applicable, but the shape of silica is colloidal silica having water as a dispersion medium, and the specific surface area is preferably 20 to 500 m 2 / g, in particular 30 It is more preferable that it is the range of -100 m <2> / g. Although the quantity of water is not specifically limited, Usually, 20-40 weight% of silica is contained in solid content in colloidal silica. The colloidal silica can be used in either an alkaline type or an acid type as long as it is compatible with the water-based acid resin of the above-mentioned composition. For example, even in the acid type, the pH can be adjusted by alkali metal hydroxide, ammonia, or the like. In particular, excellent alkali resistance can be obtained by using an alkali metal hydroxide. The addition amount is appropriate to use colloidal silica in a proportion of 30 to 300 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the resin solid content. If the colloidal silica is less than 30 parts by weight, it cannot be said that the sticking resistance of the stress relief annealing is sufficient, and if it exceeds 300 parts by weight of the colloidal silica, film formation is inferior, and the film tends to deteriorate the adhesion and corrosion resistance of the coating film. As a result, excellent punching characteristics of the present invention are not exhibited.

In baking for a short time at low temperature using the aqueous acid resin and the colloidal silica of the present invention, in order to obtain a coating having excellent corrosion resistance, the surface area occupied by the colloidal silica in the treatment liquid [specific surface area m 2 / g x solid content weight] and the ratio of the surface area [specific surface area m <2> / g x solid content weight] which an aqueous acid resin particle occupies are important requirements within a specific range.

1 is a colloidal silica having a different surface area in the same manner as an epoxy / acrylic emulsion resin having a different surface area, and a treatment solution containing 100 parts by weight of colloidal silica as a solid content with respect to 100 parts by weight of the resin solids is dried to a weight. It is a graph of the measurement results of the product plate corrosion resistance and solvent resistance of the coating film coated at a target of 0.5 g / m 2 per 1 m 2 unit area. In addition, evaluation of product corrosion resistance and solvent resistance was evaluated by the method of Example 1. The specific surface area of emulsion resin and colloidal silica was calculated | required by the Stokes calculation formula from the measured value of the average particle diameter by electron microscope observation. As can be seen from these results, even when the ratio of solid content of resin and silica is used within the above-mentioned proper range, under the condition that the surface area ratio of the resin and silica particles in the treatment liquid does not satisfy the scope of the present invention. A film having poor corrosion resistance and solvent resistance is formed.

The film cross-sectional structure formed by low temperature baking was observed by electron microscopy for two conditions in which the surface area occupied by the colloidal silica particles in the treatment liquid was (1) about 13 times and (2) about 1.8 times the surface area occupied by the emulsion resin particles. It was. The processing liquid consisted of the ratio of 150 weight part of colloidal silica solid content with respect to 100 weight part of emulsion resin solid content, and baking temperature was 150 degreeC of the reaching board temperature.

In the case of (1), silica was observed layered around the plate-shaped emulsion resin. That is, it becomes a structure in which resin particle was dotted by a silica layer. In the low temperature baking of 100-300 degreeC, since the film formation property of silica itself is weak and the binding force of particle | grains is small, it can be considered that it becomes such a film structure. In such a coating structure, there is no protection against an external atmosphere, and rust is easily generated in a high humidity environment.

On the other hand, in the case of (2), a film structure in which resin and silica were finely dispersed separately was observed. It is thought that such a structure is obtained because resins are easily bonded to each other even under low temperature baking conditions. In such a film structure, it has protection against an external atmosphere, and corrosion resistance becomes favorable.

When the ratio of silica surface area is less than 0.2 times or less, it becomes the structure which silica particle interspersed in the resin layer contrary to the case of (1), and is favorable to corrosion resistance, but it can be considered that solvent resistance deteriorates.

That is, as can be seen from the examples of the present invention, the ratio of the surface area of the silica particles satisfying the corrosion resistance and the solvent resistance is 0.2 to 10 times, and the appropriate range is 0.5 to 5 times.

3. 2 Alumina

The inventors of the present invention found that solvent resistance of the resin itself can be ensured if the resin has a glass transition point of 30 to 150 ° C. As a result of examining inorganic materials which can be prepared at low temperature baking and which do not lower the boiling vapor exposure property, it has been found that considerable boiling vapor exposure property can be obtained by using alumina in combination, and the combination of the both results in boiling vapor exposure property. I found out that it could be improved.

Moreover, alumina is mix | blended in order to enable stress relief annealing without reducing boiling water vapor exposing property. Alumina to 100 parts by weight of resin is preferably 3-300 parts by weight as Al ₂ O ₃ conversion. If the alumina is less than 3 parts by weight, the resin powder will thermally decompose upon stress relief annealing, resulting in less film residue and lower sticking properties. Moreover, when alumina exceeds 300 weight part, punching property will fall,

The alumina to be blended in the treatment liquid may be any production method as long as it is dispersed in water, and various shapes such as alumina sol and alumina flower can be applied.

However, when an alumina sol is used, it is preferable to use an organic acid as an acid of a stabilizer. Use of inorganic acids other than organic acids, such as hydrochloric acid, nitric acid, etc., results in the presence of Cl ⁻ , NO ₃ ⁻ ions in the coating and significantly lowers the corrosion resistance, and rust may occur in a short time of standing in the atmosphere. This can be prevented to some extent by the addition of an antirust agent, but is remarkably solved by using an organic acid as a stabilizer. As the kind of organic acid, various carboxylic acids such as formic acid, acetic acid and propanoic acid can be suitably applied, and carbon number and other functional groups are not particularly limited as long as they have at least one -COOH group and are water-soluble. However, even when the organic acid is used, since almost no organic acid remains in the coating film after baking, the organic acid is undetectable from the product, but the Cl ⁻ and NO ₃ ⁻ levels are extremely low.

3. 3 Alumina-containing Silica

The present inventors have also found that by using alumina-containing silica instead of the alumina, a film having excellent boiling vapor exposure of alumina and excellent corrosion resistance of silica can be obtained.

Although the alumina containing silica used by this invention is a mixture of a predetermined amount of alumina and a silica, it is preferable to become a structure which covers the silica surface with the minimum required alumina in an insulating film.

As a stabilizer of alumina, an organic acid is preferable similarly to the case where alumina is used as the inorganic colloid of 3.2 mentioned above. The amount of stabilizer to be used may be in a range where the liquid is stable by neutralizing the charge on the surface of the alumina. In the neutralization rate, an amount of 70 to 130% is preferred. This improves the corrosion resistance immediately after annealing.

The amount of alumina-containing silica relative to 100 parts by weight of the resin is preferably 3 to 300, preferably 10 to 300 parts by weight in terms of Al ₂ O ₃ + SiO ₂ . If the alumina-containing silica is less than 3 parts by weight, the resin powder is thermally decomposed at the time of stress relief annealing, resulting in less film residue and lower sticking properties. Moreover, punching property will fall when an alumina containing silica is more than 300 weight part.

Examining in more detail, it was found that the resin itself had a good boiling vapor exposure property, and found that the desired boiling water vapor exposure property and corrosion resistance after annealing could be obtained by setting the amount of alumina to 100 parts by weight of silica to be 0.01 part by weight or more. It was. As the amount of alumina with respect to the amount of silica increases, the corrosion resistance of the annealing plate tends to decrease, so the amount of alumina is made 500 parts by weight or less. Preferably it is 1-300, More preferably, it is 1-100 weight part with respect to 100 weight part of silica amounts.

Although it is not clear why alumina is excellent in boiling water vapor exposure, it can be considered that it is a difference in the particle charge of alumina and a silica, or a difference in the compactness of a film.

If the corrosion resistance is not required after annealing, the amount of silica is minimal. However, since the dehydration reaction has not yet been completed in the low-temperature baking at 150 ° C. or lower, the TIG welding agent may be damaged during low-temperature baking. Therefore, when the TIG weldability is emphasized again in low temperature baking at 150 ° C. or lower, it is effective to increase the amount of silica in the alumina-containing silica.

The boiling water vapor exposure and solvent resistance of the resin / inorganic colloid brand at low temperature baking were examined in detail, and the same results as in the case of 3.2 described above were obtained. That is, when the glass transition point of resin is 30 degreeC or more, it discovered that boiling water vapor exposing property and solvent resistance were excellent. Moreover, the film formation property at the time of low temperature baking was able to be ensured by making resin glass transition point into 150 degrees C or less.

Resin composition used here is not specifically regulated like the case of 3.2 mentioned above.

Resin suitable for the present invention can be applied to any resin composition as long as the glass transition point is 30 to 150 占 폚 as in the case of 3.2 described above. In the case of resin whose glass transition point is not clear, the softening point should just be 30-150 degreeC.

The alumina-containing silica to be blended in the treatment liquid may be any method as long as it is dispersed in water, and various shapes such as colloidal powder and powder can be applied.

4. Coating amount, coating method, baking method

Application amount

In the electromagnetic steel sheet of this invention, it is preferable that the adhesion amount of an insulating film is 0.05-4 g / m <2> by dry weight after annealing per single surface. If the adhesion amount is less than 0.05 g / m 2, the film becomes uneven and the exposure of iron and iron causes the lack of sticking, boiling steam exposure, and corrosion resistance. If the adhesion amount is more than 4 g / m 2, swelling occurs at low temperature drying. Therefore, the deposition amount of the insulating coating is preferably 0.05 to 4 g / m 2, particularly preferably 0.1 to 2 g / m 2.

Application method

The production of the electromagnetic steel sheet of the present invention can be carried out by applying a treatment liquid containing the resin, silica and alkali metals and additives other than those used as required on the surface of the steel disc and baking to form an insulating coating. have. The coating method of the treatment liquid is not particularly limited, and various methods such as a roll coater method, a flow coater method, a spray coating, a knife coater, and the like which are generally used industrially are applied. It is possible.

Baking method, baking conditions

The baking method is not particularly limited, for example, hot air, infrared, or induction heating. The baking temperature is sufficient as low temperature heating such that moisture in the coating evaporates, for example, 50 to 250 ° C., preferably 80 to 250 ° C., and more preferably 120 to 250 ° C. sheet temperature), it is possible to bake for a short time within 1 minute.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1

On the surface of the electrical steel sheet having a plate thickness of 0.5 mm, a coating liquid having a resin, silica, and alkali metal, a part of Cl and S amount of which was a predetermined amount or less was applied using a roll coater, and baked at a plate temperature of 150 ° C, After cooling, an insulating film shown in Table 1 was formed, and an electromagnetic steel sheet having an insulating film was produced.

About the obtained electrical steel sheet with an insulating film, solvent resistance, punching property, corrosion resistance and adhesiveness immediately after stress relief annealing, and sticking property were evaluated or measured according to the following method. The results of evaluation of solvent resistance and corrosion resistance of the product plate and the annealing plate are shown in Table 1, and the influence of the silica weight on the punching property, the silica weight on the sticking property, and the effect of the coating amount on the film adhesion of the product plate and the annealing plate. The influence of the coating amount on the punching property and the coating amount on the sticking property is shown in FIGS. 2 to 7, respectively.

Solvent resistance

The various solvents shown in the table were soaked in cotton wool, and the appearance change after reciprocating the coating phase five times was examined and evaluated according to the following criteria.

◎: no change

○: almost no change

△: slightly discolored

×: large change

Punchability

Punching of the steel sheet sample was carried out using a 15 mmΦ steel dice adjusted to a burr height of 10 µm, and the number of punches until the burr height reached 50 µm was determined and evaluated according to the following criteria.

◎: over 500,000 times

○: 300,000 to 500,000

△: 100,000 to 300,000

×: less than 100,000 times

Corrosion Resistance (Full Edition)

The sample of the electromagnetic steel sheet with the insulating film was subjected to a wet test (50 ° C., 100% relative humidity), and the red rust area ratio after 48 hours was determined and evaluated according to the following criteria.

◎: 0 to 20%

○: 20 to 40%

△: 40 to 60%

×: 60 to 100%

Corrosion resistance (annealed plate)

After annealing at 750 ° C. × 2 h in nitrogen, an electromagnetic steel sheet sample having an insulating film was subjected to a constant temperature and humidity test (50 ° C., relative humidity of 80%), and the red rust area ratio after 14 days was determined and evaluated according to the following criteria.

◎: 0 to 20%

○: 20 to 40%

△: 40 to 60%

×: 60 to 100%

Adhesion

An electromagnetic steel sheet sample and a stress relief annealing plate sample obtained by annealing the electromagnetic steel sheet at 750 ° C. for 2 hours in nitrogen were attached to the surface of the steel sheet with a cellophane tape, and 180 ° bending recovery tests at 20 mm Φ were then performed. Subsequently, after peeling off a cellophane tape, the film peeling rate was calculated | required and the following reference | standard evaluated.

◎: no peeling

○: 20% peeling

△: peeling 20% to peeling 40%

X: Peeling 40%-whole peeling

Anti-sticking property

After annealing a sample of 10 sheets of electromagnetic steel sheets sheared at 50 mm angles under a nitrogen atmosphere at 750 ° C. for 2 hours while applying a load (200 g / cm 2), 500 g of weights were dropped on the samples, and the electrons overlapped with each other. The drop height when the steel plate was divided into five pieces was measured and evaluated according to the following criteria.

◎: 10 cm or less

○: 10 to 15 cm

△: 15 to 30 cm

×: more than 30 cm

No. Suzy Silica Type Silica Weight ^* alkali Cl weight ^*** S weight ^*** Kinds Kinds Weight ^** One acryl Weather Silica 50 Na 0.8 <0.001 <0.01 Invention 2 Polyethylene / acrylic Colloidal silica 50 K, Na 5.0 <0.001 0.03 3 Acrylic / styrene Colloidal silica 50 Li, Na 0.2 <0.001 0.02 4 Polyethylene / acrylic / urethane Colloidal silica 3 Li, Na 0.2 0.005 0.05 5 Acrylic / Acrylonitrile Colloidal silica 300 Na 0.9 <0.001 <0.01 6 Epoxy / acrylic Colloidal silica 100 Li, Na 0.1 <0.001 <0.01 7 Polyethylene / acrylic Colloidal silica 100 Li, Na 0.6 <0.001 <0.01 8 Polyethylene / acrylic Colloidal silica 100 Li, Na 1.2 0.008 0.08 9 acryl Colloidal silica 100 Na 0.05 <0.001 <0.01 Comparative example 10 Acrylic / styrene Colloidal silica 100 Na 8.5 <0.001 <0.01

*: Parts by weight of SiO _{2 relative} to 100 parts by weight of the resin.

**: The total weight of M ₂ O (M is an alkali metal) equivalent by weight in 100 parts by weight of SiO ₂ .

Colloidal silica is prepared from water glass (sodium silicate), and all contain a small amount of Na in order to post-add Li, Na, and K as necessary.

***: SiO parts by weight of Cl or S in the film to ₂₁₀₀ parts by weight basis.

No. Coating amount (g / ㎡) Inner Castle Corrosion Resistance Corrosion Resistance Annealing Plate Remarks Hexane xylene Methanol ethanol One 1.0 ◎ ◎ ◎ ◎ ○ ◎ Invention 2 0.05 ◎ ◎ ◎ ◎ ○ ○ 3 4.0 ◎ ◎ ◎ ◎ ◎ ◎ 4 0.8 ◎ ◎ ◎ ○ ○ ○ 5 0.9 ◎ ◎ ◎ ◎ ○ ◎ 6 1.5 ◎ ◎ ◎ ○ ◎ ◎ 7 0.3 ◎ ◎ ◎ ◎ ◎ ◎ 8 0.5 ◎ ◎ ◎ ◎ × × 9 0.8 ◎ × × × × ◎ Comparative example 10 1.2 ◎ ◎ ◎ ◎ △ △ Whitening during long term storage

As can be seen from Table 1 and FIGS. 2 to 7, all of the examples of the present invention are electromagnetic steel sheets having an insulating film having excellent solvent resistance, punching property, adhesiveness before and after stress relief annealing, sticking property, etc. What is below quantification is excellent also in the corrosion resistance before and behind a stress relief annealing.

Example 2

The film of Table 2 was formed in the electromagnetic steel plate surface of 0.5 mm of plate | board thickness. Application | coating was performed by the roll coater, and it baked and cooled at 150 degreeC of the reaching board temperature, and performed each performance test. In the same manner as in Example 1, solvent resistance, punching property, adhesiveness (product plate, annealing plate), and sticking property were measured and evaluated.

Morphology

The film appearance after baking at 150 degreeC plate | board temperature was visually evaluated in accordance with the following reference | standard.

◎: show uniform appearance, no crack, swelling, stickiness

○: slight cracking, swelling

△: large crack, swelling, slight stickiness

×: large crack, swelling, stickiness

As can be seen from Table 2, all of the examples of the present invention are electromagnetic steel sheets with an insulating coating having excellent solvent resistance, punching properties, adhesion before and after stress relief annealing, sticking properties, and the like. In addition, although the Example in a table aims at the improvement only by the performance which was considered as a basis, the example which improves other various performances among them was shown in the remark that it becomes a comparative example with respect to other various performances.

No. Suzy Silica Type Silica Weight ^* alkali Coating amount (g / ㎡) Kinds Tg (℃) Kinds Weight ^** One acryl 30 Colloidal silica 100 Li, Na 0.5 1.0 Invention 2 Epoxy / acrylic 150 Weather Silica 50 Na 0.8 0.8 3 Polyethylene / acrylic 80 Colloidal silica 50 K, Na 5.0 0.05 4 Acrylic / styrene 60 Colloidal silica 50 Li, Na 0.2 4.0 5 Polyethylene / acrylic / urethane 80 Colloidal silica 3 Li, Na 0.2 0.8 6 Acrylic / Acrylonitrile 40 Colloidal silica 300 Na 0.9 0.9 7 Epoxy / acrylic 110 Colloidal silica 100 Li, Na 0.1 1.5 8 acryl 0 Colloidal silica 100 Na 0.05 0.8 Comparative example 9 Epoxy / acrylic 170 Colloidal silica 50 Li, Na 0.5 0.8 10 acryl 30 Colloidal silica 2 Li, Na 0.5 0.8 Invention 11 Acrylic / styrene 60 Colloidal silica 400 Li, Na 0.7 0.8 12 Acrylic / styrene 60 Colloidal silica 50 Li, Na 2.2 5.0 13 Polyethylene / acrylic 80 Colloidal silica 50 Li, Na 0.7 0.03 14 Acrylic / styrene 60 Colloidal silica 100 Na 8.5 1.2 Comparative example

*: Parts by weight of SiO _{2 relative} to 100 parts by weight of the resin.

**: The total weight of M ₂ O (M is an alkali metal) equivalent by weight in 100 parts by weight of SiO ₂ .

Colloidal silica is prepared from water glass (sodium silicate), and all contain a small amount of Na in order to post-add Li, Na, and K as necessary.

No. Film formation at plate temperature 150 ℃ Inner Castle Punchability Adhesive board Adhesive Annealing Plate Sticking Remarks Hexane xylene Methanol ethanol Acetone One ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ ◎ Invention 2 ○ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 3 ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ○ 4 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ 5 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ 6 ◎ ◎ ◎ ◎ ◎ ○ ○ ○ ◎ ◎ 7 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 8 ◎ ◎ × × × × ◎ ◎ ◎ ◎ Comparative example 9 × ◎ ◎ ◎ ◎ ◎ ◎ × ◎ ◎ 10 ◎ ◎ ○ ○ ○ × ◎ ◎ ◎ × The present invention 11 × ◎ ◎ ◎ ◎ ◎ × × ◎ ◎ 12 × ◎ ◎ ◎ ◎ ◎ ◎ × × ◎ 13 ◎ ◎ ◎ ◎ ◎ ◎ × ◎ ◎ × 14 ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ ◎ White discoloration for long term storage Comparative example

Example 3

The film of Table 3 was formed in the electromagnetic steel plate surface of 0.5 mm of plate | board thickness. Application | coating was performed by the roll coater, and it baked and cooled at 150 degreeC of the reaching board temperature, and performed each performance test. In the same manner as in Examples 1 and 2, film formation, solvent resistance, punching resistance, corrosion resistance (product plate, annealing plate), adhesiveness (product plate, annealing plate), and sticking properties were measured and evaluated.

As can be seen from Table 3, all of the examples of the present invention are electromagnetic steel sheets having an insulating coating having excellent solvent resistance, punching resistance, corrosion resistance before and after stress relief annealing, adhesiveness, sticking property, and the like. In addition, although the Example in the table aims at the improvement only by the performance focused on fundamentally, there exist some examples which improve other various performance among them, and it showed in the remark that it becomes a comparative example about other various performance.

No. Suzy Silica Type Silica Weight ^* alkali Kinds Tg (℃) Kinds Weight ^** 2-1 acryl 30 Colloidal silica 100 Li, Na 0.5 Invention 2-2 Epoxy / acrylic 150 Weather Silica 50 Na 0.8 2-3 Polyethylene / acrylic 80 Colloidal silica 50 K, Na 5.0 2-4 Acrylic / styrene 60 Colloidal silica 50 Li, Na 0.2 2-5 Polyethylene / acrylic / urethane 80 Colloidal silica 3 Li, Na 0.2 2-6 Acrylic / Acrylonitrile 40 Colloidal silica 300 Na 0.9 2-7 Epoxy / acrylic 110 Colloidal silica 100 Li, Na 0.1 2-8 Polyethylene / acrylic 80 Colloidal silica 100 Li, Na 0.6 2-9 acryl 0 Colloidal silica 100 Na 0.05 Comparative example 2-10 Epoxy / acrylic 170 Colloidal silica 50 Li, Na 0.5 2-11 acryl 30 Colloidal silica 2 Li, Na 0.5 Invention 2-12 Acrylic / styrene 60 Colloidal silica 400 Li, Na 0.7 2-13 Acrylic / styrene 60 Colloidal silica 50 Li, Na 2.2 2-14 Polyethylene / acrylic 80 Colloidal silica 50 Li, Na 0.7 2-15 Acrylic / styrene 60 Colloidal silica 100 Na 8.5 2-16 Polyethylene / acrylic 80 Colloidal silica 100 Li, Na 1.2 Comparative example

*: Parts by weight of SiO _{2 relative} to 100 parts by weight of the resin.

**: The total weight of M ₂ O (M is an alkali metal) equivalent by weight in 100 parts by weight of SiO ₂ .

Colloidal silica is prepared from water glass (sodium silicate), and all contain a small amount of Na in order to post-add Li, Na, and K as necessary.

***: Cl or S parts by weight of the coating on the SiO ₂ in terms of 100 parts by weight.

No. Cl weight ^*** S weight Coating amount (g / ㎡) Film formation at plate temperature 150 ℃ Inner Castle Hexane xylene Methanol ethanol Acetone 2-1 <0.001 <0.01 1.0 ◎ ◎ ◎ ◎ ◎ ○ Invention 2-2 <0.001 <0.01 0.8 ○ ◎ ◎ ◎ ◎ ◎ 2-3 <0.001 0.03 0.05 ◎ ◎ ◎ ◎ ◎ ◎ 2-4 <0.001 0.02 4.0 ◎ ◎ ◎ ◎ ◎ ◎ 2-5 0.005 0.05 0.8 ◎ ◎ ◎ ◎ ◎ ◎ <0.001 2-6 <0.01 0.9 ◎ ◎ ◎ ◎ ◎ ○ <0.001 2-7 <0.01 1.5 ◎ ◎ ◎ ◎ ◎ ◎ 2-8 <0.001 <0.01 0.3 ◎ ◎ ◎ ◎ ◎ ◎ 2-9 <0.001 <0.01 0.8 ◎ ◎ × × × × Comparative example 2-10 <0.001 <0.01 0.8 × ◎ ◎ ◎ ◎ ◎ 2-11 <0.001 <0.01 0.8 ◎ ◎ ○ ○ ○ × The present invention 2-12 <0.001 <0.01 0.8 × ◎ ◎ ◎ ◎ ◎ 2-13 <0.001 <0.01 5.0 × ◎ ◎ ◎ ◎ ◎ 2-14 <0.001 <0.01 0.03 ◎ ◎ ◎ ◎ ◎ ◎ 2-15 <0.001 <0.01 1.2 ◎ ◎ ◎ ◎ ◎ ○ 2-16 0.008 0.08 0.5 ◎ ◎ ◎ ◎ ◎ ◎ Comparative example

No. Punchability Corrosion Resistance Corrosion Resistance Annealing Plate Adhesive board Adhesive Annealing Plate Sticking 2-1 ◎ ○ ◎ ◎ ◎ ◎ Invention 2-2 ◎ ◎ ◎ ◎ ◎ ◎ 2-3 ○ ○ ○ ◎ ◎ ○ 2-4 ◎ ◎ ◎ ○ ○ ◎ 2-5 ◎ ○ ○ ◎ ◎ ○ 2-6 ○ ○ ◎ ○ ◎ ◎ 2-7 ◎ ◎ ◎ ◎ ◎ ◎ 2-8 ○ ◎ ◎ ◎ ◎ ◎ 2-9 ◎ × ◎ ◎ ◎ ◎ Comparative example 2-10 ◎ ◎ ◎ × ◎ ◎ 2-11 ◎ ◎ × ◎ ◎ × The present invention 2-12 × × ◎ × ◎ ◎ 2-13 ◎ ◎ ◎ × × ◎ 2-14 × × △ ◎ ◎ × 2-15 ◎ △ △ ◎ ◎ ◎ 2-16 ◎ × × ◎ ◎ ◎ Comparative example

Example 4

Dispersion type water-soluble epoxy resin with a specific surface area of 330 m 2 / g and alkaline type colloidal silica with a specific surface area of 110 m 2 / g forcibly emulsified on the surface of the steel sheet after the final finishing annealing having a thickness of 0.5 mm containing 0.2% of Si. After mixing in the ratio shown in Table 4, it applied with the grooved roll. The coating amount of the coating was adjusted to reduce the pressure of the rubber roll at a goal of 0.5 g / m 2. Then, baking was carried out at 200 ° C of the reaching plate temperature. Each performance test was then performed. Adhesiveness (product board, annealing board), corrosion resistance (product board, annealing board), and solvent resistance were measured and evaluated similarly to Examples 1 and 2.

Baking Strength by Tensile Test: The steel sheets after coating were overlapped by 15 cm 2, loaded with 25 kg / cm 2 and subjected to dry N ₂ annealing at 750 ° C. for 2 hours, followed by evaluation of the weld strength of the coating (kg / cm 2). . If the intensity | strength is 1 kg / cm <2> or less, there is no problem practically.

Table 4 shows the results of the quality test.

No. Treatment fluid composition Adhesion Corrosion resistance Bake Strength by Tensile Test (㎏ / ㎠) Solvent resistance Resin (part by weight) Silica (parts by weight) Surface Area Ratio ^* (Silica / Resin) Full game Annealing Plate Full game Annealing Plate 123 100100100 01530 ―0.050.1 ◎◎◎ × △ ○ ◎◎◎ ×× ○ 8.94.11.0 ××× Comparative example 4567 100100100100 50100200300 0.20.30.71.0 ◎◎◎◎ ○○○○ ◎◎◎ △ ◎◎◎ ○ 0.80.50.50.2 ○ ◎◎◎ Invention 89 100100 400500 1.31.7 ○ × △ × ×× ◎ ○ 0.20.1 ◎◎ Comparative example

* Surface area ratio = (silica solids x specific surface area / resin solids x specific surface area) in the treatment liquid

The conditions of No 1 and No 2 in which colloidal silica content is less than 30 weight part of this invention are high fusion strength of a film, and baking resistance after stress relief annealing is not enough. Moreover, after annealing, when the silica content was small because of thermal decomposition of the resin, the corrosion resistance after annealing was observed to be deteriorated. The condition of No3 in which the surface area ratio of silica does not satisfy the range of this invention is inferior to solvent resistance. 400 weight part and 500 weight part of silica content exceeding the range of this invention are inferior to the adhesiveness and corrosion resistance of a film.

Example 5

Using a water-based acid resin and colloidal silica having different surface areas shown in Table 5 on the same steel sheet as in Example 4, the treatment liquid consisting of 150 parts by weight of silica solids was dried to 0.3 g / m 2 with respect to 100 parts by weight of the resin solids. After apply | coating with the grooved rubber roll, baking was performed in the hot stove so that reaching plate temperature might be 100 degreeC. Then, each performance test was done. In the same manner as in Example 1, adhesion (product plate, annealing plate), corrosion resistance (product plate, annealing plate), and solvent resistance were measured and evaluated.

Table 5 shows the results of the quality test.

No. Treatment fluid Adhesion Corrosion resistance Solvent resistance Water based resin Colloidal silica Surface Area Ratio (Silica / Resin) Full game Annealing Plate Full game Annealing Plate Furtherance Specific surface area (㎡ / g) Kinds Specific surface area (㎡ / g) 12 Epoxy epoxy 330330 Silica A Silica B 450100 2.00.5 ◎◎ ◎ ○ ◎◎ ◎◎ ◎◎ Invention 3 Epoxy 330 Silica D 20 0.1 ◎ ○ ◎ △ × Comparative example 45 Epoxy epoxy 120120 Silica B Silica D 10020 1.30.3 ◎◎ ◎◎ ◎◎ ◎◎ ◎ ○ Invention 67 Epoxy / acrylic epoxy / acrylic 7070 Silica A Silica D 45020 9.60.4 ◎◎ ○ ◎ ○○ ○○ ◎◎ Invention 8 acryl 40 Silica A 450 16.9 ○ × × ○ ◎ Comparative example 910 Acrylic Acrylic 4040 Silica B Silica C 10045 3.81.7 ○ ◎ ○○ ○○ ○○ ◎ ○ Invention 11 Polyethylene / acrylic 55 Silica A 450 12.3 ◎ △ × ○ ○ Comparative example 1213 Polyethylene / acrylic polyethylene / acrylic 5555 Silica B Silica D 10020 2.70.5 ◎◎ ◎◎ ○○ ○○ ◎◎ Invention

Sample No 3 in which the surface area ratio of silica in the treatment liquid and the surface area ratio of the aqueous acid resin (silica specific surface area × solid content weight / resin specific surface area × solid content weight) does not satisfy the range of 0.2 to 10 of the present invention is poor in solvent resistance. , Sample No 8 and No 11 are inferior in adhesiveness and corrosion resistance. In the present invention, it shows good solvent resistance despite the low baking temperature of 100 ° C.

Example 6

0.5 mm by weight of colloidal silica with a specific surface area of 90 m 2 with respect to 100 parts by weight of an emulsion resin of epoxyacryl copolymer having a specific surface area of 70 m 2 on a 0.5 mm thick cold rolled steel plate subjected to final annealing and temper rolling in a continuous annealing line. Using a treatment liquid (surface area ratio of silica / resin = 1.9), drying was applied with a grooved rubber roll so that the adhesion amount was in the range of 0.05 g / m 2 to 3 g / m 2, and then the reaching plate temperature was set to 100 ° C. Baking in a hot stove. Adhesiveness (product board, annealing board), corrosion resistance (product board, annealing board), and baking strength were measured and evaluated similarly to Examples 1 and 4.

Table 6 shows the results of the quality test.

No. Coating amount (g / ㎡) Adhesion Corrosion resistance Bake Strength by Tensile Test (㎏ / ㎠) Remarks Full game Annealing Plate Full game Annealing Plate One 0.05 ◎ ○ △ × 11.1 Comparative example 23456 0.10.20.51.02.0 ◎◎◎◎◎ ○○○○○ ○ ◎◎◎◎ ○○○○ ◎ 0.70.30.50.20.2 Invention 7 3.0 ◎ × ◎ ◎ 0.2 Comparative Example of Black Discoloration After Annealing Comparative example

Compared with sample No1, all the examples of this invention of sample No2-6 show favorable baking resistance, and adhesiveness and corrosion resistance are also favorable. Corrosion resistance and baking resistance were good in No7 apply | coated by the excess coating amount, but after annealing, a large amount of carbon adhere | attached on the surface of a coating film by resin decomposition, and it adhered to the cellophane tape, and adhesiveness worsened.

Example 7

The film of Table 7 was formed in the electromagnetic steel plate surface of 0.5 mm of plate | board thickness. Application | coating was performed by the roll coater, and it baked and cooled at 150 degreeC of reaching board temperature, and tested. In the same manner as in Examples 1 and 2, film forming properties, punching properties, adhesiveness (product plates, annealing plates) and sticking properties were measured and evaluated.

Boiling Vapor Exposure

The appearance after 30 minutes of boiling steam exposure was examined.

◎: no change

○: almost no change

△: slightly discolored (white discoloration, rust, etc.)

×: large change (white discoloration, rust, etc.)

Corrosion resistance

The product plate was evaluated by the red rust area ratio after 14 days of constant temperature and humidity test (50 degreeC, relative humidity 80 degreeC). Moreover, according to the test method of the same product board as Example 1, the difference was not recognized in evaluation.

◎: 0 to less than 5%

○: less than 5 to 15%

△: less than 15 to 30%

×: 30 to 100%

As can be seen from Table 7, all of the examples of the present invention are an electromagnetic steel sheet having an insulating film which is excellent in boiling water vapor exposing property and solvent resistance, and excellent in punchability and also able to withstand stress relief annealing. In addition, although the Example in the table aims at the improvement only by the performance focused on fundamentally, there exist some examples which improve other various performance among them, and it showed in the remark that it becomes a comparative example about other various performance.

No. Suzy Al ₂ O ₃ (alumina) SiO ₂ (silica) weight ^** Coating amount g / ㎡ Film formation at plate temperature 150 ℃ Kinds Tg ℃ Stabilizer Weight ^* One acryl 30 Acetic acid 100 ― 0.5 ◎ Invention 2 Epoxy 150 Acetic acid 50 ― 0.8 ○ 3 acryl 80 Acetic acid 50 ― 0.05 ◎ ◎ 4 acryl 40 Acetic acid 50 ― 4.0 5 Epoxy 110 Acetic acid 3 ― 0.2 ◎ 6 Epoxy 110 Acetic acid 300 ― 1.5 ◎ 7 acryl 40 Propionic acid 100 ― 1.2 ◎ 8 acryl 0 Acetic acid 100 ― 0.8 ◎ Comparative example 9 Epoxy 170 Acetic acid 50 ― 0.8 △ 10 acryl 80 ― ― 100 0.5 ◎ 11 acryl 80 Acetic acid One ― 0.8 ◎ Invention 12 acryl 40 Acetic acid 400 ― 0.8 ◎ 13 acryl 40 Acetic acid 50 ― 5.0 ◎ 14 acryl 40 Acetic acid 50 ― 0.02 ◎ 15 acryl 40 Direct 100 ― 0.8 ◎ 16 acryl 40 Hydrochloric acid 100 ― 1.2 ◎

*: Parts by weight of Al ₂ O _{3 based} on 100 parts by weight of resin

**: parts by weight of SiO _{2 relative} to 100 parts by weight of the resin

No. Boiling Water Vapor Exposure Inner Castle Punchability Constant temperature and humidity corrosion resistance Adhesive board Adhesive Annealing Plate Sticking Hexane xylene Methanol ethanol One ○ ◎ ○ ○ ○ ◎ ○ ◎ ◎ ◎ Head person 2 ◎ ◎ ◎ ◎ ◎ ◎ ◎ △ ◎ ◎ 3 ◎ ◎ ◎ ◎ ◎ △ △ ◎ ◎ △ 4 ○ ◎ ◎ ○ ○ ◎ ◎ △ △ ◎ 5 ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ △ 6 ○ ◎ ◎ ◎ ◎ △ ◎ ◎ ◎ ◎ 7 ○ ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ◎ 8 × ◎ × × × ◎ × ◎ ◎ ◎ Comparative example 9 ◎ ◎ ◎ ◎ ◎ ◎ △ × ◎ ◎ 10 × ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 11 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ × Invention 12 ○ ◎ ◎ ○ ○ × ◎ ◎ ◎ ◎ 13 ○ ◎ ◎ ○ ○ ◎ ◎ × × ◎ 14 ○ ◎ ◎ ○ ○ × × ◎ ◎ × 15 ○ ◎ ◎ ○ ○ × × ◎ ◎ ◎ 16 ○ ◎ ◎ ○ ○ × × ◎ ◎ ◎

Example 8

The film of Table 8 was formed in the electromagnetic steel plate surface of 0.5 mm of plate | board thickness. Application | coating was performed by the roll coater, and it baked and cooled at 150 degreeC of the reaching board temperature, and performed each performance test. Film formation, boiling steam exposure, solvent resistance, punching property, adhesiveness (product plate, annealing plate), and sticking property were measured and evaluated in the same manner as in Examples 1, 2, and 7.

Corrosion resistance

The product plate and the plate after annealing at 750 ° C. × 2 h in nitrogen were evaluated by the red rust area ratio after 14 days of constant temperature and humidity test (50 ° C., relative humidity 80%). Moreover, in the test method of the same product board as Example 1, the difference was not recognized in evaluation.

Full Annealing Plate

◎: less than 0 to 5% ◎: less than 0 to 20%

○: less than 5 to 15% ○: less than 20 to 40%

△: less than 15 to 30% △: less than 40 to 60%

×: 30 to 100% ×: 60 to 100%

As can be seen from Table 8, the examples of the present invention are all excellent in boiling water vapor exposure, solvent resistance, excellent punching resistance, and can withstand stress relief annealing. .

Suzy Alumina-containing Silica Coating amount g / ㎡ Kinds Tg ℃ Alumina Stabilizer Alumina Weight ^* Silica Weight ^** Gross weight ^*** Alumina Ratio ^**** One acryl 30 Acetic acid 5 45 50 11.1 0.5 Invention 2 Epoxy 150 Acetic acid 10 90 100 11.1 0.8 3 acryl 80 Acetic acid 25 25 50 100.0 0.05 4 acryl 40 Acetic acid 10 90 100 11.1 4.0 5 Epoxy 110 Acetic acid 0.1 10 10.1 1.0 0.2 6 Epoxy 110 Acetic acid 40 260 300 15.4 1.5 7 acryl 40 Propanoic acid One 2 3 50.0 1.2 8 acryl 0 Acetic acid 10 90 100 11.1 0.8 Comparative example 9 Epoxy 170 Acetic acid 10 90 100 11.1 0.8 10 acryl 40 Acetic acid 0 100 100 0.0 0.8 11 acryl 80 Acetic acid 0.5 1.5 2 33.3 0.8 Invention 12 acryl 40 Acetic acid 100 300 400 33.3 0.8 13 acryl 80 Acetic acid 85 15 100 566.7 0.8 14 acryl 40 Acetic acid 10 90 100 11.1 5.0 15 acryl 40 Acetic acid 1.6 14.2 15.8 11.3 0.03 16 acryl 40 Nitric acid 10 90 100 11.1 0.8 17 acryl 40 Hydrochloric acid 10 90 100 11.1 1.2

*: Parts by weight of Al ₂ O _{3 based} on 100 parts by weight of resin

**: parts by weight of SiO _{2 relative} to 100 parts by weight of the resin

***: Al ₂ O ₃ + SiO ₂ equivalent parts by weight based on 100 parts by weight of resin

****: Al ₂ O ₃ parts by weight based on 100 parts by weight of SiO ₂

No. Film formation at plate temperature 150 ℃ Boiling Water Vapor Exposure Inner Castle Punchability Constant temperature and humidity corrosion resistance Corrosion Resistance Annealing Plate Adhesive board Adhesive Annealing Plate Sticking Hexane xylene Methanol ethanol One ◎ ◎ ◎ ○ ○ ○ ◎ ◎ ◎ ◎ ◎ ◎ Head person 2 ○ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 3 ◎ ○ ◎ ◎ ◎ ◎ △ △ ◎ ◎ ◎ △ 4 ◎ ◎ ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ◎ ◎ 5 ◎ ○ ◎ ◎ ◎ ◎ ○ ○ ◎ ◎ ◎ ○ 6 ◎ ◎ ◎ ◎ ◎ ◎ △ ○ ◎ ◎ ◎ ◎ 7 ◎ ◎ ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ◎ ○ 8 ◎ × ◎ ◎ △ △ ◎ × ◎ ◎ ◎ ◎ Comparative example 9 △ ◎ ◎ ◎ ◎ ◎ ◎ △ ◎ × ◎ ◎ 10 ◎ × ◎ ◎ ○ ○ ◎ ◎ ◎ ◎ ◎ ◎ 11 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ × ◎ ◎ × Invention 12 ◎ ◎ ◎ ◎ ○ ○ × × ◎ ◎ ◎ ◎ 13 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ × ◎ ◎ ◎ 14 ◎ ◎ ◎ ◎ ○ ○ ◎ ◎ ◎ × × ◎ 15 ◎ ○ ◎ ◎ ○ ○ × × ◎ ◎ ◎ × 16 ◎ ○ ◎ ◎ ○ ○ ◎ × × ◎ ◎ ◎ 17 ◎ ○ ◎ ◎ ○ ○ ◎ × × ◎ ◎ ◎

According to the present invention, an electronic steel sheet having an insulating film which can be produced by low temperature baking, can be stress relief annealed, and has excellent solvent resistance, corrosion resistance, boiling steam exposure, adhesion, sticking property, film forming property, and weldability. Is provided.

Claims (14)

An electrical steel sheet capable of stress relief annealing and excellent solvent resistance, which has an insulating film containing a resin and an inorganic colloid which is silica, alumina or alumina-containing silica. A method for producing an electrical steel sheet, which is capable of stress relief annealing and excellent solvent resistance, which is obtained by baking the insulating film at a steel sheet temperature of 50 to 250 ° C. according to claim 1. The M ₂ O (M: alkali metal) according to claim 1, wherein the inorganic colloid in the insulating film is silica, and the insulating film is M ₂ O (M: alkali metal) for silica having 100 parts by weight in terms of SiO ₂ of at least one alkali metal selected from Li, Na and K. ) An electrical steel sheet capable of stress relief annealing containing 0.1 to 5 parts by weight and excellent in solvent resistance. 4. The electrical steel sheet according to claim 3, wherein Cl is 0.005 parts by weight or less and S is 0.05 parts by weight or less with respect to silica having 100 parts by weight in terms of SiO _{2 in} terms of SiO ₂ . The electrical steel sheet according to claim 3, wherein stress relief annealing is possible in an amount of 3 to 300 parts by weight in terms of SiO ₂ with respect to a resin having 100 parts by weight of silica in the insulating coating, and excellent in solvent resistance. The electrical steel sheet according to claim 3, wherein the glass relief point of the resin in the insulating coating is 30 to 150 캜, capable of stress relief annealing and excellent solvent resistance. The surface area (specific surface area) according to claim 3, wherein the resin is an aqueous acid resin having a particle size, contains 30 to 300 parts by weight of colloidal silica solids, and 100 parts by weight of the aqueous acid resin solids, and the colloidal silica solids particles occupy. × solid content weight) Stress relief annealing with an insulating film is possible and solvent resistance is achieved by applying and then baking a coating liquid of 0.2 to 10 times the surface area (specific surface area × solid content weight) occupied by this aqueous acid resin solid particles. Excellent electromagnetic steel sheet. In the method for producing the electromagnetic steel sheet according to claim 3, the resin is an aqueous acid resin having a particle size, and 30 to 300 parts by weight of colloidal silica solid content is added to 100 parts by weight of the aqueous acid resin solid content, and the colloidal silica solid particles are Surface area to be occupied (specific surface area x solid content weight) Applying a coating liquid containing water adjusted to 0.2 to 10 times the surface area (specific surface area x solid content weight) occupied by the water-based resin solid particles, is applied to the steel plate surface and then baked. A method for producing an electrical steel sheet capable of stress relief annealing and excellent solvent resistance. The electrical steel sheet according to claim 1, wherein the inorganic colloid in the insulating coating is alumina, and the stress relief annealing is excellent in solvent resistance, wherein the resin has a glass potential of 30 to 150 캜. The electrical steel sheet according to claim 1, wherein the inorganic colloid in the insulating coating is alumina-containing silica, and the stress relief annealing is excellent in solvent resistance, wherein the resin has a glass potential of 30 to 150 캜. The electrical steel sheet according to claim 9 or 10, wherein the insulating film contains an organic acid as a stabilizer of alumina and is capable of stress relief annealing and is excellent in solvent resistance. The electrical steel sheet according to claim 9 or 10, wherein the alumina or the alumina-containing silica in the insulating coating is 3 to 300 parts by weight in terms of Al ₂ O ₃ + SiO ₂ , capable of stress relief annealing and having excellent solvent resistance. The electrical steel sheet according to claim 10, wherein the alumina in the insulating coating is 0.01 to 500 parts by weight in terms of Al ₂ O _{3 based} on 100 parts by weight of silica in terms of SiO ₂ , and has excellent solvent resistance. The electrical steel sheet according to claim 3, 9 or 10, wherein stress relief annealing is possible, and the adhesion amount of the insulating coating is 0.05 to 4 g / m 2, and the solvent resistance is excellent.