JP5569433B2 - Insulating coating solution for electrical steel sheet and electrical steel sheet with insulating film - Google Patents

Description

  The present invention relates to an insulating coating solution for an electrical steel sheet and an electrical steel sheet with an insulating film formed using the same.

Currently, generally used insulating coatings for electrical steel sheets can be broadly classified into the following three types.
(1) Inorganic coating that emphasizes weldability and heat resistance and resists strain relief annealing (2) Resin-containing inorganic coating that resists strain relief annealing with the aim of achieving both punching resistance and weldability (ie, semi-organic coating) )
(3) Organic coating that cannot be strain-relieved and annealed for special applications Among these, it is a coating containing inorganic components shown in the above (1) and (2) that is resistant to strain relief as a general-purpose product. It contained a chromium compound.

  On the other hand, according to the increase in environmental awareness, demands of customers, etc., the present applicant has proposed an electrical steel sheet having an insulating coating that does not contain a chromium compound (see, for example, Patent Documents 1 to 3). .)

JP 2005-268630 A JP 2006-169567 A JP 2008-127663 A

  However, when the present inventors examined the electrical steel sheets with insulating coatings described in Patent Documents 1 to 3, depending on the content ratio of the Zr compound and the resin, either the corrosion resistance or the powder blowing resistance may be inferior. Clarified that there is room for improvement.

  Therefore, the present invention provides an insulating coating solution for an electrical steel sheet that can form an insulating coating of an electrical steel sheet with an insulating coating that is excellent in both corrosion resistance and powder blowing resistance, and an electromagnetic with an insulating coating formed using the same. It is an object to provide a steel plate.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the corrosion resistance of the electrical steel sheet with an insulating coating formed using an insulating coating solution for an electrical steel sheet containing a compound having a predetermined number of nitrogen atoms and hydroxyl groups, respectively, and The present inventors completed the present invention by finding that the powder blowing resistance was good. That is, the present invention provides the following (1) to (3).

(1) An insulating film treatment liquid for an electromagnetic steel sheet for forming an insulating film of an electromagnetic steel sheet,
In an aqueous solvent, containing a Zr compound, a resin, and nitrite ions,
The content of the resin is 20 to 60 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ),
An insulating coating solution for an electrical steel sheet, wherein the content of the nitrite ion is such that the molar ratio (ion / Zr) of Zr atoms in the Zr compound to the nitrite ion is 0.01-10.

(2) further containing at least one compound selected from the group consisting of a P compound, a B compound and a Si compound;
The content of the P compound (P ₂ O ₅ equivalent), 20 to 70 parts by mass relative to the Zr compound (ZrO ₂ equivalent) 100 parts by weight,
The content of Compound B (B ₂ O ₃ equivalent), 1 to 10 parts by mass relative to the Zr compound (ZrO ₂ equivalent) 100 parts by weight,
The insulating coating solution for an electrical steel sheet according to (1), wherein the content of the Si compound (in terms of SiO ₂ ) is 20 to 70 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ).

(3) An electrical steel sheet with an insulating coating having an insulating coating,
An electrical steel sheet with an insulating coating, wherein the insulating coating is formed using the insulating coating solution for an electrical steel sheet according to (1) or (2).

  As shown below, according to the present invention, an insulating coating solution for an electrical steel sheet that can form an insulating coating of an electrical steel sheet with an insulating coating that is excellent in both corrosion resistance and powder blowing resistance, and formed using the same An electrical steel sheet with an insulating coating can be provided.

[Insulating coating solution for electrical steel sheets]
The insulating coating solution for an electrical steel sheet of the present invention (hereinafter simply abbreviated as “the processing solution of the present invention”) contains a Zr compound, a resin, and nitrite ions in an aqueous solvent. The content is 20 to 60 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ), and the content of the nitrite ion is the molar ratio of the Zr atom in the Zr compound to the nitrite ion ( This is a treatment liquid for forming an insulating coating of an electromagnetic steel sheet in such an amount that the ion / Zr) is 0.01 to 10.
The aqueous solvent, Zr compound, resin, nitrite ion, and other components that may be optionally contained are described in detail below.

<Aqueous solvent>
The aqueous solvent used in the treatment liquid of the present invention may be water, but a mixed solvent of water and a water-miscible organic solvent (for example, alcohol, ketone, etc.) can also be used.

<Zr compound>
The Zr compound used in the treatment liquid of the present invention is not particularly limited. Specifically, for example, zirconium acetate, zirconium propionate, zirconium oxychloride, zirconium nitrate, ammonium zirconium carbonate, potassium zirconium carbonate, zirconium zirconium chloride, zirconium sulfate , Zirconium phosphate, sodium zirconium phosphate, potassium hexafluorozirconium, tetranormal propoxyzirconium, tetranormalbutoxyzirconium, zirconium tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium tributoxy systemate, etc. These may be used alone or in combination of two or more.
Of these, ammonium zirconium carbonate and potassium zirconium carbonate are preferred from the viewpoint of stability in an aqueous solvent.

Such a Zr compound has a strong binding force with oxygen and can be strongly bonded to an oxide or hydroxide on the surface of the electrical steel sheet.
Moreover, since such Zr compounds have 4 or more, generally 6 to 8 bonds, it is possible to form a network with Zr compounds or other inorganic compounds without using chromium. A tough insulating coating can be formed.

In the present invention, the mass% of the Zr compound in the treatment liquid of the present invention is not particularly limited, but from the viewpoint of workability (mainly applicability) and stability, the ratio in the treatment liquid of the present invention is 1 to 10. It is preferable to become mass%. Within this range, it may be appropriately prepared so as to be 20 to 70% by mass, which is a preferable ratio of the Zr compound (in terms of ZrO ₂ ) in the insulating coating formed using the treatment liquid of the present invention.

<Resin>
The resin used in the treatment liquid of the present invention is not particularly limited. Specifically, for example, acrylic resin, alkyd resin, polyolefin resin, styrene resin, vinyl acetate resin, epoxy resin, phenol resin, polyester resin, urethane resin, melamine Aqueous resins (including emulsions and dispersions) such as resins can be used, and these may be used alone or in combination of two or more.
Among these, polyester resin, acrylic resin, epoxy resin, and urethane resin are preferable because the corrosion resistance of the electrical steel sheet with an insulating coating becomes better.

In the present invention, the content of the resin, the Zr compound is 20 to 60 parts by weight with respect to (ZrO ₂ equivalent) 100 parts by weight, is preferably 30 to 50 parts by weight.
When the content of the resin is within this range, the shrinkage stress during the formation of the insulating coating made of the Zr compound or the like can be relaxed, so that the punchability of the electrical steel sheet with the insulating coating is improved. In addition, scratch resistance after strain relief annealing is also improved.

<Nitrite ion>
Nitrite ions used in the treatment liquid of the present invention are not particularly limited. Specific examples thereof include dissolving nitrites such as nitrous acid, sodium nitrite, potassium nitrite, calcium nitrite, and ammonium nitrite in the aqueous solvent. Nitrite ions are used. In addition, the said nitrite may be used individually by 1 type, and may use 2 or more types together.

In the present invention, the content of the nitrite ion is such that the molar ratio (ion / Zr) between the Zr atom and the nitrite ion in the Zr compound is 0.01-10.
Here, the Zr atoms in the Zr compound are all Zr atoms contained in the treatment liquid of the present invention.
The Zr atom in the Zr compound can be determined by ICP (abbreviation of “Inductively Coupled Plasma”, the same applies hereinafter) emission analysis. It can be determined according to the method described in 43.1 Nitrite ion (NO ₂ ⁻ ).
When the content of the nitrite ions is within this range, the corrosion resistance and the powder blowing resistance are improved, and an electrical steel sheet with an insulating coating excellent in appearance after strain relief annealing can be produced.
Here, the reason why the corrosion resistance and the powder blowing resistance become better is that the nitrite ion becomes an obstructing substance for the polymerization reaction (crosslinking) of the Zr compound, and as a result of delaying the condensation reaction, It is considered that the aggregation was suppressed and the occurrence of coating cracks starting from the aggregate could be suppressed.

  In the present invention, the content of the nitrite ion is such that the molar ratio (ion / Zr) is 0.1 to 0.1 to produce an electrical steel sheet with an insulating coating having better corrosion resistance and powder blowing resistance. 3 is preferable, the molar ratio (ion / Zr) is more preferably 0.1 to 2, and the molar ratio (ion / Zr) is 0.1 to 1. More preferred is the amount.

<Hydroxyl-containing amine compound>
The treatment liquid of the present invention is a hydroxyl group-containing amine compound having one N atom and one or more hydroxyl groups because an electrical steel sheet with an insulating coating with better corrosion resistance and powder blowing resistance can be produced. It is preferable to contain.
Here, the reason why the corrosion resistance and the powder blowing resistance become better is that, like the nitrite ion, the addition of the hydroxyl group-containing amine compound slows down the polymerization reaction (crosslinking) of the Zr compound, and baking is performed. This is considered to be because the aggregation of the Zr compound during drying was suppressed and the occurrence of coating cracks starting from the aggregate of the Zr compound was suppressed. The reason why the polymerization reaction (crosslinking) of the Zr compound is slow is considered to be because the hydroxyl group-containing amine compound acts as a stabilizer that exerts a chelating action on the Zr compound.

  As said hydroxyl-containing amine compound, the compound represented by following formula (1) is mentioned, for example.

(In the formula, R ¹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 8 carbon atoms, R ² represents a divalent aliphatic hydrocarbon group having 1 to 4 carbon atoms, and m represents 1 to 3) And a plurality of R ^{1 s} when m is 1 may be the same or different, and a plurality of R ^{2 s} when m is 2 or 3 are the same or different. May be.)

In the above formula (I), the monovalent hydrocarbon group having 1 to 8 carbon atoms in R ¹ is, for example, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group or a propyl group; Group, an aryl group having 6 to 8 carbon atoms such as xylyl group; and the like.
In the formula (I), examples of the divalent aliphatic hydrocarbon group having 1 to 4 carbon atoms represented by R ² include a methylene group, an ethylene group, a propylene group (propane-1,3-diyl group), And an alkylene group of a butylene group (butane-1,4-diyl group).

Specific examples of the compound represented by the formula (1) include, for example, methanolamine, monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, and N-ethylethanol. Amine, N-methyldiethanolamine, N-ethyldiethanolamine, N-phenyldiethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, propanolamine, butanolamine and the like are used alone. Or two or more of them may be used in combination.
Of these, diethanolamine and triethanolamine are preferable because of their high addition effect.

In the present invention, the content of the hydroxyl group-containing amine compound is such that the molar ratio (N / Zr) between the Zr atom in the Zr compound and the N atom in the hydroxyl group-containing amine compound is 0.01-4. The amount is preferably 0.1 to 1, and more preferably 0.1 to 1.
Here, as described above, the Zr atoms in the Zr compound are all Zr atoms contained in the treatment liquid of the present invention, and the N atom in the hydroxyl group-containing amine compound is the present invention as a hydroxyl group-containing amine compound. All N atoms contained in the treatment liquid.
Further, as described above, the Zr atom in the Zr compound can be obtained by ICP emission analysis, and the N atom in the hydroxyl group-containing amine compound can be determined by gas chromatography using a Varian amine analysis column. It can be determined by analyzing the amount of the compound.

<P compound, B compound, Si compound>
The treatment liquid of the present invention has a P compound, a B compound, and an Si compound in order to produce an electrical steel sheet with an insulating coating that has better corrosion resistance and powder blowing resistance, and has excellent scratch resistance after strain relief annealing. It preferably contains at least one compound selected from the group consisting of In addition, when the B compound is contained, an electrical steel sheet with an insulating coating that is further excellent in anti-sticking property can be produced.

Specific examples of the P compound include phosphoric acids such as orthophosphoric acid, anhydrous phosphoric acid, linear polyphosphoric acid, and cyclic metaphosphoric acid; magnesium phosphate, aluminum phosphate, ammonium phosphate, calcium phosphate, phosphoric acid. Phosphate compounds such as zinc; and the like. These may be used alone or in combination of two or more.
In the present invention, the content of the P compound optionally contained (in terms of P ₂ O ₅ ) is preferably 20 to 70 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ). More preferably, it is -70 mass parts.

Specific examples of the B compound include boric acid, orthoboric acid, metaboric acid, tetraboric acid, sodium metaborate, sodium tetraborate and the like, and these may be used alone. In addition, two or more kinds may be used in combination.
The B compound is not limited to the above examples. For example, the B compound may be a compound that dissolves in water to generate borate ions, and the borate ions are polymerized linearly or cyclically. May be.
In the present invention, the content of the B compound that is optionally contained (in terms of B ₂ O ₃ ) is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ). More preferably, it is -6 mass parts.

Furthermore, specific examples of the Si compound include colloidal silica, fumed silica, alkoxysilane, and siloxane. These may be used alone or in combination of two or more. Good.
In the present invention, the content of the Si compound optionally contained (in terms of SiO ₂ ) is preferably 20 to 70 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ), preferably 30 to 70. More preferred is part by mass.

<Other additives>
The treatment liquid of the present invention can contain, in addition to the above-described components, additives usually used in the insulation film treatment liquid, other inorganic compounds, organic compounds, and the like, if necessary.
Here, the additive is a component added to further improve the performance and uniformity of the insulating coating, and includes, for example, a surfactant, a rust inhibitor, a lubricant, an antioxidant, a pH adjuster, an antifoaming agent. Agents, leveling agents and the like.
The amount of the additive is not particularly limited as long as the effect of the present invention is not impaired, but is preferably about 5 parts by mass or less with respect to 100 parts by mass of the Zr compound (ZrO ₂ equivalent). .

  The method for preparing the treatment liquid of the present invention is not particularly limited. For example, the above-described Zr compound, resin and nitrite ion (salt), and optionally containing a hydroxyl group-containing amine compound, P compound, B compound, It can be prepared by adding a Si compound and other additives to the aqueous solvent described above and stirring.

[Electromagnetic steel sheet with insulation coating]
The electrical steel sheet with an insulation coating of the present invention is an electrical steel sheet with an insulation coating in which an insulation coating is formed on the surface of the electrical steel sheet using the treatment liquid of the present invention described above.
Below, the electrical steel sheet (material) and the insulation coating which comprise the electrical steel sheet with an insulation coating of this invention are explained in full detail.

<Electromagnetic steel sheet (material)>
The electromagnetic steel sheet (material) is not particularly limited, and any conventionally known electromagnetic steel sheet can be used.
Specifically, a so-called soft iron plate (electric iron plate) having a high magnetic flux density; a general cold-rolled steel plate such as SPCC; a non-oriented electrical steel plate containing Si or Al to increase specific resistance; it can.

<Insulating coating>
The insulating coating is an insulating coating formed using the above-described treatment liquid of the present invention.
In the present invention, the method for forming the insulating coating is not particularly limited. For example, the insulating coating can be formed by applying and baking the above-described treatment liquid of the present invention on the surface of the electromagnetic steel sheet (material).
Here, the method of applying the treatment liquid of the present invention is not particularly limited, and various methods such as a roll coater, a flow coater, a spray, a knife coater and the like that are generally used in industry are applicable.
Similarly, a method such as a hot air method, an infrared method, an induction heating method, or the like that is usually performed can also be applied to the baking method after coating. In addition, the baking temperature should just be a normal level, and should just be about 150-350 degreeC by ultimate steel plate temperature.
Moreover, in this invention, before apply | coating the process liquid of this invention, you may perform the degreasing process, such as an alkali, and pickling processes, such as hydrochloric acid, a sulfuric acid, and phosphoric acid, on the surface of an electromagnetic steel plate (raw material).

Although the adhesion amount of the insulating coating is not particularly limited, it is preferably about 0.05 to 5 g / m ² , more preferably 0.1 to 3.0 g / m ² per side.
Here, the adhesion amount, that is, the total solid content mass of the insulating coating of the present invention can be measured from the decrease in mass after removing the coating by alkali peeling. Moreover, when there is little adhesion amount, it can measure from the calibration curve of a fluorescent X ray and an alkali peeling method.
If the adhesion amount is 0.05 g / m ² or more, corrosion resistance and insulation can be ensured. If the adhesion amount is 5 g / m ² or less, the adhesion is excellent, and defects and cracks are generated during paint baking. There is no, and paintability improves.
In the present invention, the insulating coating is preferably provided on both surfaces of the electrical steel sheet, but depending on the purpose, only one surface may be provided.

Since the insulating film is formed using the treatment liquid of the present invention, the ratio of the Zr compound (in terms of ZrO ₂ ) in the dried insulating film (hereinafter abbreviated as “dry film” in this paragraph) is 20 It is preferable that it is -70 mass%.
Similarly, the ratio of the resin in the dry film is preferably 10 to 40% by mass in terms of solid content. In addition, the solid content conversion value of resin can be calculated | required from the residual ratio after drying in 200 degreeC and 10 minutes of an organic resin liquid.
Also, when the treatment liquid of the present invention optionally containing P compound, the ratio of P compound in the dry film (P ₂ O ₅ equivalent), preferably from 10 to 50 mass%.
Similarly, when the treatment liquid of the present invention optionally contains a B compound, the ratio of the B compound (in terms of B ₂ O ₃ ) in the dry film is preferably 0.1 to 5% by mass.
Similarly, when the treatment liquid of the present invention optionally contains a Si compound, the ratio of the Si compound (in terms of SiO ₂ ) in the dry film is preferably 10 to 50% by mass.
In the present invention, impurities such as Hf, HfO ₂ , TiO ₂ , and Fe ₂ O ₃ may be mixed in the insulating film, but the ratio of these impurities in the dry film is 1% by mass or less. Is preferred.

The electrical steel sheet with an insulating coating of the present invention can be subjected to strain relief annealing to remove, for example, strain due to punching.
The strain relief annealing atmosphere is not particularly limited, but is preferably an atmosphere in which iron is hardly oxidized such as an N ₂ atmosphere and a DX gas atmosphere.
Here, the dew point is set high, for example, Dp: about 5 to 60 ° C., and the corrosion resistance can be further improved by slightly oxidizing the surface and the cut end face.
The strain relief annealing temperature is preferably 700 to 900 ° C, more preferably 750 to 850 ° C.
Further, the holding time of the strain relief annealing temperature is preferably long and more preferably 2 hours or more.

  Hereinafter, the treatment liquid and the electrical steel sheet with an insulating coating according to the present invention will be described in detail using examples. However, the present invention is not limited to this.

(Examples 1-81, Comparative Examples 1-11)
Each component shown in Table 1 below was added to deionized water in the proportions (mass%, parts by mass, molar ratio) shown in Table 1 below, and the treatment liquid was prepared by stirring. The addition concentration with respect to the amount of deionized water was adjusted to 50 g / L.
Here, in Table 1 below, the addition amount of the Zr compound represents mass% in the entire treatment liquid, and the addition amounts of the B compound, the P compound, the Si compound, and the resin are all based on 100 parts by mass of the Zr compound (mass). The addition amount of the nitrite ion and the hydroxyl group-containing amine compound represents the molar ratio with the Zr atom in the Zr compound.
The types of Zr compounds are shown in Table 2, the types of B compounds are shown in Table 3, the types of P compounds are shown in Table 4, the types of Si compounds are shown in Table 5, and the types of nitrite ions (salts). Are shown in Table 6 below, types of hydroxyl group-containing amine compounds are shown in Table 7 below, and types of organic resins are shown in Table 8 below.

Each prepared treatment solution was rolled onto a test piece surface cut into a width of 150 mm and a length of 300 mm from a 0.5 mm thick electromagnetic steel sheet [A230 (JIS C 2552 (2000))]. After applying and baking with a hot air baking oven at the baking temperature shown in Table 1 (attained steel plate temperature), it was allowed to cool to room temperature to form an insulating coating.
The corrosion resistance, powder blowing resistance, punchability, TIG weldability and water resistance of each of the electrical steel sheets with insulating coatings (hereinafter referred to as “test material”) thus obtained were evaluated by the following methods. . The results are shown in Table 9.
In addition, scratch resistance, sticking resistance, appearance, and corrosion resistance after performing strain relief annealing at 750 ° C. for 2 hours in a nitrogen atmosphere were evaluated by the following methods. The results are shown in Table 9.
The evaluation method of each characteristic is as follows. In each evaluation, ◎◎ to ○ are acceptable.

(1) Corrosion resistance A wet test (50 ° C., relative humidity ≧ 98%) was performed on the specimen, and the red rust occurrence rate after 48 hours was visually observed and evaluated by area ratio.
<Criteria>
◎: Red rust area ratio less than 2% ◎: Red rust area ratio 2% or more, less than 5% ○: Red rust area ratio 5% or more, less than 10% ×: Red rust area ratio 10% or more

(2) Powder blowing resistance On the surface of the insulating coating, a felt with a contact area of 20 mm × 10 mm was reciprocated 100 times with a load of 3.8 kg / cm ² (0.4 MPa), and the coating remaining amount after the test was evaluated. The coating amount before and after the test was calculated by the Zr count ratio by fluorescent X-rays.
<Criteria>
◎◎: remaining rate of film 95%
A: Film remaining rate 90-95%
○: Residual rate of film 80 to 90%
×: film remaining rate less than 80%

(3) Punching property The specimen was punched using a 15 mmφ steel die until the burr height reached 50 μm, and the number of punches was evaluated.
<Criteria>
◎: More than 1 million times ◎: More than 500,000 times, less than 1 million times ○: More than 100,000 times, less than 500,000 times ×: Less than 100,000 times

(4) TIG weldability The test material was laminated at a pressure of 9.8 MPa (100 kgf / cm ² ) so as to have a thickness of 30 mm, and TIG weldability was performed on the end portion under the following conditions. .
・ Welding current: 120A
Ar gas flow rate: 6 liters / min
-Welding speed: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 cm / min
<Criteria>
The superiority or inferiority was determined by the maximum welding speed at which the number of blow holes satisfied 5 or less per bead.
◎: 60 cm / min or more ◎: 50 cm / min or more, less than 60 cm / min ○: 30 cm / min or more, less than 50 cm / min ×: less than 30 cm / min

(5) Water resistance The test material was exposed to boiling water vapor for 30 minutes, and the change in appearance was visually observed.
<Criteria>
◎: No change at all ◎: Slight discoloration is observed visually ○: Discoloration is partially recognized visually ：: Discoloration is clearly recognized visually

(6) Scratch resistance after strain relief annealing The surface of the specimen subjected to strain relief annealing in a nitrogen atmosphere at 750 ° C. for 2 hours was scratched with a steel plate shear edge, and the degree of scratches and powder blowing was visually determined. .
<Criteria>
◎◎: Scratch and powder spray are not observed at all ◎: Scratch marks and powder spray are slightly recognized ○: Scratch marks and powder spray are clearly recognized ×: The film is peeled off and powder spray is clearly seen

(7) Sticking resistance after strain relief annealing Ten specimens of 50 mm square are stacked and strain is removed under conditions of 750 ° C. for 2 hours in a nitrogen atmosphere while applying a load of 20 kPa (200 g / cm ² ). Annealing was performed.
Next, 500 g of weight was dropped on the overlapped specimens, and the drop height when dividing into 5 parts was investigated.
<Criteria>
◎◎: 5 cm or less ◎: More than 5 cm, 10 cm or less ○: More than 10 cm, 25 cm or less ×: More than 25 cm

(8) Appearance after strain relief annealing The specimen was subjected to strain relief annealing at 750 ° C. for 2 hours in a nitrogen atmosphere, and then the appearance of the steel sheet cooled to room temperature was visually observed.
<Criteria>
◎: Appearance after annealing is completely uniform ◎: Slight unevenness is observed in the appearance after annealing ○: Appearance is slightly observed in the appearance after annealing ×: Significant speckled pattern is observed in the appearance after annealing Be

(9) Corrosion resistance after strain relief annealing The specimen was subjected to strain relief annealing at 750 ° C. for 2 hours in a nitrogen atmosphere, and then a wet test (50 ° C., (Relative humidity ≧ 98%) was performed, the red rust occurrence rate after 48 hours was visually observed, and the area ratio was evaluated.
<Criteria>
◎: Red rust area ratio less than 2% ◎: Red rust area ratio 2% or more, less than 5% ○: Red rust area ratio 5% or more, less than 10% ×: Red rust area ratio 10% or more

As shown in Table 9, it was found that Comparative Examples 1, 5 and 9 in which the resin content was less than the predetermined range were inferior in powder blowing resistance and punching resistance, and further inferior in corrosion resistance after strain relief annealing. .
Further, it was found that Comparative Examples 4 and 8 having a resin content larger than the predetermined range were inferior in powder blowing resistance and TIG weldability, and inferior in scratch resistance and corrosion resistance after strain relief annealing.
Further, it was found that Comparative Examples 2, 6 and 10 having a small content of nitrite ions were inferior in corrosion resistance and powder blowing resistance, and further inferior in corrosion resistance after strain relief annealing.
Further, it was found that Comparative Examples 3, 7 and 11 having a large content of nitrite ions were inferior in powder blowing resistance and water resistance, and further inferior in corrosion resistance after strain relief annealing.

On the other hand, the specimens prepared using the treatment liquids of Examples 1 to 81 prepared by blending a specific amount of nitrite ions with respect to the Zr compound are not only corrosion resistance and powder blowing resistance but also punchability. Further, it has been found that TIG weldability and water resistance are also improved, and further, scratch resistance, sticking resistance, appearance and corrosion resistance after strain relief annealing are also improved.
In particular, Examples 25, 53, and 81, which were prepared by using a hydroxyl group-containing amine compound having one N atom and one or more hydroxyl groups together with nitrite ions, all of the measured film properties were better. I understood that.

Claims (3)

An insulating coating solution for an electromagnetic steel sheet for forming an insulating coating on the electromagnetic steel sheet,
In an aqueous solvent, containing a Zr compound, a resin, and nitrite ions,
The content of the resin is 20 to 60 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ),
An insulating film treatment solution for an electrical steel sheet, wherein the content of the nitrite ion is an amount such that a molar ratio (ion / Zr) of Zr atoms to the nitrite ion in the Zr compound is 0.01 to 10. Furthermore, it contains at least one compound selected from the group consisting of P compound, B compound and Si compound,
The content of the P compound (P ₂ O ₅ equivalent), is said Zr compound 20 to 70 parts by weight with respect to (ZrO ₂ equivalent) 100 parts by weight,
The content of the B compound (B ₂ O ₃ equivalent), 1 to 10 parts by mass relative to the Zr compound (ZrO ₂ equivalent) 100 parts by weight,
_{2. The} insulating coating solution for an electrical steel sheet according to claim 1, wherein the content of the Si compound (in terms of SiO ₂ ) is 20 to 70 parts by mass with respect to 100 parts by mass of the Zr compound (in terms of ZrO ₂ ). An electrical steel sheet with an insulating coating having an insulating coating,
An electrical steel sheet with an insulating coating, wherein the insulating coating is formed using the insulating coating solution for an electrical steel sheet according to claim 1 or 2.