JP7040508B2 - Electrical steel sheet with insulation coating - Google Patents

Description

The present invention relates to an electromagnetic steel sheet with an insulating coating, and is particularly suitable as a material for an iron core of an automobile motor or an electric device, and is suitable for an application in which an electromagnetic steel sheet is bonded with an anaerobic acrylic adhesive to form a core. The present invention relates to an electromagnetic steel sheet with an insulating coating having excellent adhesive compatibility.

Laminated electrical steel sheets used for iron cores of automobile motors and electrical equipment have conventionally been manufactured by stacking a plurality of electrical steel sheets having an insulating coating and then integrating them by caulking or welding. .. In recent years, there has been an increasing demand for higher efficiency of electrical equipment for energy saving. Along with this, there is a tendency to reduce the thickness of the electrical steel sheet used for the laminated electrical steel sheet in order to reduce the eddy current loss. However, when the electrical steel sheet is thin, not only is it difficult to caulk and weld, but also the end face of the laminated electrical steel sheet is easily opened, and it is difficult to maintain the shape as an iron core.

In order to solve this problem, the following two techniques have been proposed in place of the technique of integrating electrical steel sheets by caulking or welding. The former is a technique for forming a laminated electrical steel sheet by thermocompression bonding a plurality of electrical steel sheets having an adhesive insulating film formed on the surface thereof. The latter is a technique of applying an adhesive to an electromagnetic steel sheet with an insulating film and laminating a plurality of electrical steel sheets to form a laminated electrical steel sheet. It is known that an anaerobic acrylic adhesive is often used as an adhesive applied to the latter technique.

Patent Document 1 states that "a substituent other than the alkoxy group bonded to Si is a trialkoxysilane and / or a dialkoxysilane consisting of only at least one non-reactive substituent selected from a hydrogen, an alkyl group, and a phenyl group. The alkoxysilane (A) and the silane coupling agent (B) are contained in a mass ratio (A / B) of 0.05 to 1.0, and the average particle size is 0.08 to 0.9 μm. In addition, a surface treatment agent containing 2 to 30% by mass of plate-shaped silica (C) having an aspect ratio of 10 to 100 with respect to the total solid content is applied to at least one surface of the electromagnetic steel plate and dried to have an insulating film. "Characteristic electromagnetic steel plate with insulating film" is described. Since this insulating coating does not have an adhesive function, it may be applicable to the latter technique.

Japanese Unexamined Patent Publication No. 2013-64195

The electrical steel sheet with an insulating coating of Patent Document 1 is excellent in corrosion resistance and tension pad resistance required for electrical steel sheets in recent years, even if the insulating coating does not contain a chromium compound. The term "tension resistant pad" as used herein means that the insulating film is peeled off when the surface of the insulating film is rubbed with a felt-shaped tension pad used to hold the electromagnetic steel plate for slitting the coil or the like. It is a kusa.

However, according to the study by the present inventors, the electromagnetic steel plate with an insulating coating of Patent Document 1 cannot sufficiently obtain the adhesive strength against the anaerobic acrylic adhesive, and there is room for improvement in this respect. found.

Therefore, in view of the above problems, it is an object of the present invention to provide an electromagnetic steel plate with an insulating film having excellent adhesive strength, corrosion resistance, and tension pad resistance to an anaerobic acrylic adhesive.

As a result of diligent studies by the present inventors in order to solve the above problems, as a component of the surface treatment agent for forming an insulating film on the electromagnetic steel plate, a silane coupling agent is the main component, and trialkoxysilane and / or dialkoxy is used. It was found that the above object can be achieved by further containing a predetermined amount of urethane resin in addition to containing silane and plate-shaped silica.

The abstract structure of the present invention completed based on the above findings is as follows.
[1] A trialkoxysilane and / or a dialkoxysilane (A) in which the substituent other than the alkoxy group bonded to Si consists of only at least one non-reactive substituent selected from a hydrogen, an alkyl group, and a phenyl group. )When,
Silane coupling agent (B) and
Plate-shaped silica (C) having an average particle size of 0.08 to 0.9 μm and an aspect ratio of 10 to 100,
Urethane resin (D) and
water and,
An electromagnetic steel sheet with an insulating coating having an insulating coating obtained by applying a surface treatment agent containing the following conditions (1) to (3) to at least one surface of the electrical steel sheet and drying the steel sheet.
(1) The mass ratio (A / B) of the trialkoxysilane and / or the dialkoxysilane (A) to the silane coupling agent (B) is 0.05 to 1.00.
(2) The content of the plate-shaped silica (C) is 2 to 30% by mass with respect to the total mass of (A) to (D) in the surface treatment agent.
(3) The content of the urethane resin (D) is 2 to 30% by mass with respect to the total mass of (A) to (D) in the surface treatment agent.

[2] A trialkoxysilane and / or a dialkoxysilane (A) in which the substituent other than the alkoxy group bonded to Si consists of only at least one non-reactive substituent selected from a hydrogen, an alkyl group, and a phenyl group. )When,
Silane coupling agent (B) and
Plate-shaped silica (C) having an average particle size of 0.08 to 0.9 μm and an aspect ratio of 10 to 100,
Urethane resin (D) and
Lubricant (E) and
water and,
An electromagnetic steel sheet with an insulating film having an insulating film obtained by applying a surface treatment agent containing the above conditions (1) to (4) so as to satisfy the following conditions (1) to (4) on at least one surface of the electrical steel sheet and drying it.
(1) The mass ratio (A / B) of the trialkoxysilane and / or the dialkoxysilane (A) to the silane coupling agent (B) is 0.05 to 1.00.
(2) The content of the plate-shaped silica (C) is 2 to 30% by mass with respect to the total mass of (A) to (E) in the surface treatment agent.
(3) The content of the urethane resin (D) is 2 to 30% by mass with respect to the total mass of (A) to (E) in the surface treatment agent.
(4) The content of the lubricant (E) is 0.5 to 20% by mass with respect to the total mass of (A) to (E) in the surface treatment agent.

The electromagnetic steel plate with an insulating coating of the present invention is excellent in all of adhesive strength, corrosion resistance, and tension pad resistance to an anaerobic acrylic adhesive.

Hereinafter, an electromagnetic steel sheet with an insulating coating according to an embodiment of the present invention will be described.

(Electrical steel sheet)
In the present embodiment, the electrical steel sheet used as the material is not particularly limited, and any conventionally known electrical steel sheet is suitable. That is, any of so-called soft iron plates (electric iron plates) having a high magnetic flux density, general cold-rolled steel sheets such as SPCC, and non-oriented electrical steel sheets containing Si or Al in order to increase specific resistance are advantageous.

(Surface treatment agent)
In the surface treatment agent (surface treatment agent for electromagnetic steel plates) used in the present embodiment, at least one non-reactive substituent in which the substituent other than the alkoxy group bonded to Si is selected from hydrogen, alkyl group, and phenyl group. A trialkoxysilane and / or a dialkoxysilane (A) consisting of only a group, a silane coupling agent (B), an average particle size of 0.08 to 0.9 μm, and an aspect ratio of 10 to 100. It contains a plate-shaped silica (C), a urethane resin (D), and water, and optionally contains a lubricant (E).

[Trialkoxysilane and / or Dialkoxysilane (A)]
The surface treatment agent used in this embodiment contains trialkoxysilane and / or dialkoxysilane (A).

The type of trialkoxysilane is not particularly limited, and is represented by the general formula R1Si (OR') ₃ , and one or more of them can be used. R1 is a non-reactive substituent selected from hydrogen, alkyl groups, and phenyl groups. When R1 is an alkyl group, it is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 3 carbon atoms. R'is an alkyl group, preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 2 carbon atoms. For example, methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, hydrolyzate thereof, and the like can be used. Among them, trialkoxysilane in which R1 is an alkyl group is preferable from the viewpoint of more excellent corrosion resistance of the electrical steel sheet.

The type of dialkoxysilane is not particularly limited, and is represented by the general formula R2R3Si (OR'') ₂ , and one or more of them can be used. Here, R2 and R3 are non-reactive substituents selected from hydrogen, alkyl groups, and phenyl groups. When R2 and R3 are alkyl groups, they are preferably linear or branched alkyl groups having 1 to 6 carbon atoms, and more preferably linear or branched alkyl groups having 1 to 3 carbon atoms. R ″ is an alkyl group, preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 2 carbon atoms. For example, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, and hydrolysates thereof can be used. Of these, dialkoxysilanes in which R2 and R3 are alkyl groups are preferable from the viewpoint of better corrosion resistance of the electrical steel sheet.

[Silane Coupling Agent (B)]
The surface treatment agent used in this embodiment contains a silane coupling agent (B). The type of the silane coupling agent (B) is not particularly limited, and is represented by the general formula XSi (R4) _n (OR) _3-n (where n is 0, 1 or 2), and one or more of them may be used. Can be used at the same time. X is a molecular chain having at least one reactive functional group selected from an active hydrogen-containing amino group, an epoxy group, and a mercapto group. R4 is an alkyl group, preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 2 carbon atoms. OR is an arbitrary hydrolyzable group, R is, for example, an alkyl group, preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a linear or branched group having 1 to 2 carbon atoms. Alkyl group of. Further, R is, for example, an acyl group (-COR5), R5 is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 2 carbon atoms. Is. Examples of the silane coupling agent (B) include N- (aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyl. Dimethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, hydrolyzate thereof and the like can be used. Among them, a silane coupling agent having an amino group or an epoxy group is preferable from the viewpoint of more excellent corrosion resistance of the electromagnetic steel sheet.

[Content ratio of component (A) to component (B)]
In the present embodiment, the mass ratio (A / B) of the trialkoxysilane and / or the dialkoxysilane (A) to the silane coupling agent (B) is in the range of 0.05 to 1.00. When the mass ratio exceeds 1.00, the amount of the silane coupling agent (B) is not sufficient, and the toughness of the insulating coating cannot be sufficiently obtained. As a result, the tension pad resistance is deteriorated, and scratches and film peeling during handling are likely to occur. In the present disclosure, the tension pad resistance can be remarkably improved by containing a larger amount of the silane coupling agent (B) than the trialkoxysilane and / or the dialkoxysilane (A). From this point of view, the mass ratio (A / B) is 1.00 or less, preferably 0.50 or less. On the other hand, if the mass ratio (A / B) is too low, the TIG weldability deteriorates. From this point of view, the mass ratio (A / B) is 0.05 or more, preferably 0.10 or more.

[Plate-shaped silica (C)]
The surface treatment agent used in this embodiment contains plate-shaped silica (C). This plate-like silica is also called leaf-like silica or scaly silica, and has a layered silicic acid structure in which a large number of thin layers of SiO ₂ are laminated. The plate-shaped silica preferably has non-crystalline or microcrystalline properties. The plate-shaped silica can be obtained by producing agglomerated particles in which thin-layer primary particles are laminated and pulverizing the agglomerated particles. Since such plate-shaped silica has a layered form, it has excellent corrosive substance permeation inhibitory properties as compared with general silica particles such as colloidal silica, and since it has many hydroxyl groups, it has excellent adhesion and is soft. Because of its existence, it has excellent slipperiness. Further, when a surface treatment agent containing plate-shaped silica is applied, the surface treatment agent remains even on the convex portion of the steel sheet surface where the amount of application tends to be small, and the surface treatment agent can be uniformly applied according to the unevenness of the steel sheet surface. Therefore, the corrosion resistance is not inferior.

The plate-shaped silica (C) preferably has an average particle size of 0.08 to 0.9 μm and an aspect ratio of 10 to 100, and has an average particle size of about 0.1 to 0.5 μm. The aspect ratio is more preferably 20 to 90. When the average particle size is 0.08 μm or more and the aspect ratio is 10 or more, there is an effect on the film morphology and the film is sufficiently uniform. When the average particle size is 0.9 μm or less and the aspect ratio is 100 or less, the trialkoxysilane and / or the dialkoxysilane (A) and the silane coupling agent (B) are sufficiently incorporated into the insulating film. Therefore, the tension pad resistance is sufficient.

The plate-shaped silica (C) has an average particle size of 0.1 to 0.3 μm and an aspect ratio of 10 to 50, which is more preferable because of its excellent punching property. When the average particle size is 0.1 μm or more, powder is not generated much by crushing the plate-shaped silica by punching, and the mold is not contaminated, so that the punching property is excellent. Further, the larger the average particle size of the plate-shaped silica is, the more the die wear tends to be during punching. However, when the average particle size is 0.3 μm or less, the die wear does not become a problem and the punching property is excellent. Further, when the aspect ratio is 10 to 50, it is easily deformed at the time of punching as described above, and is particularly excellent in punching property. Further, when the aspect ratio is 50 or less, it is possible to form a more uniform film according to the unevenness of the surface of the steel sheet, so that the corrosion resistance is also excellent.

In the present specification, the "average particle size" of the plate-shaped silica is a plane perpendicular to the thickness of the plate-shaped silica when the cross section of the insulating coating is observed with a scanning electron microscope (SEM) at a magnification of 20,000 times. It is assumed that the major axis in the above means the average length of all particles in the field of view. Further, in the present specification, the "aspect ratio" of the plate-shaped silica is the major axis in the plane perpendicular to the thickness of the plate-shaped silica for each particle when the cross section of the insulating coating is observed at a magnification of 20,000 times by SEM. / The value of the ratio of the maximum thickness shall mean the value averaged for all the particles in the field of view.

The content of the plate-shaped silica (C) is preferably in the range of 2 to 30% by mass with respect to the total mass of (A) to (E) in the surface treatment agent, and is preferably 20% by mass or less. That is, the content means the content of (A) to (D) with respect to the total mass when the surface treatment agent does not contain the lubricant (E). When the content is 2% by mass or more, an electromagnetic steel sheet having excellent uniform coating properties can be obtained, and when the content is 30% by mass or less, the corrosion resistance and the tension pad resistance are not deteriorated.

[Urethane resin (D)]
It is important that the surface treatment agent used in this embodiment contains a urethane resin (D). The urethane resin (D) is not particularly limited as long as it is a copolymer having a plurality of urethane bonds, and examples thereof include a polyether urethane resin, a polyester urethane resin, and a polycarbonate urethane resin. Alternatively, two or more types can be used.

The weight average molecular weight of the urethane resin is not particularly limited, but is preferably in the range of 5000 to 750000. In the present specification, the weight average molecular weight of the urethane resin shall be calculated by the gel permeation chromatography (GPC) method, specifically by the following method. As the measuring device in the GPC method, a high-speed GPC device (HLC-8320GPC manufactured by Tosoh Corporation) is used. The relationship between the known weight average molecular weight and the elution time of the standard sample is obtained in advance, and a calibration curve is prepared in which the weight average molecular weight can be obtained from the elution time. The elution time of the urethane resin is measured under the following equipment and operating conditions, and the weight average molecular weight (in terms of polystyrene) is calculated with reference to the calibration curve.
<Device and operating conditions>
Separation column: TSKgelSuperAWM-H manufactured by Tosoh Corporation (used by connecting two in series)
Detector: Differential refractometer Column temperature: 40 ° C
Mobile phase: N, N-dimethylformamide (10 mmоl / L LiBr) manufactured by Kanto Chemical Co., Inc.
Standard sample: Standard polystyrene kit (PStQuick B manufactured by Tosoh Corporation)
Sample concentration: 0.1% by mass
Sample injection amount: 30 μL (microliter)
Flow velocity: 0.5 mL / min

It is important that the content of the urethane resin (D) is 2 to 30% by mass with respect to the total mass of (A) to (E) in the surface treatment agent, and it is preferably 15% by mass or less. That is, the content means the content of (A) to (D) with respect to the total mass when the surface treatment agent does not contain the lubricant (E). When the content is 2% by mass or more, sufficient adhesive strength to the anaerobic acrylic adhesive is obtained, and when the content is 30% by mass or less, the corrosion resistance and the tension pad resistance are not deteriorated.

[Lubricant (E)]
The surface treatment agent used in the present embodiment may optionally contain a lubricant (E) in order to improve punching property and tension pad resistance. Examples of the lubricant (E) include polyethylene wax, polyethylene oxide wax, polypropylene oxide wax, carnauba wax, paraffin wax, montan wax, rice wax, Teflon (registered trademark) wax, carbon disulfide, graphite and the like. Further, as the lubricant (E), a nonionic acrylic resin may be used. As the nonionic acrylic resin, for example, in the presence of a nonionic surfactant (emulsifier) having a vinyl-based monomer such as acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, and styrene in a polyethylene oxide structure or a polypropylene oxide in its structure. , Acrylic resin emulsified with a nonionic emulsifier, such as an aqueous emulsion emulsion-polymerized in water. From these lubricants, one kind or two or more kinds can be used.

When the surface treatment agent contains the lubricant (E), the content thereof is preferably 0.5 to 20% by mass with respect to the total mass of (A) to (E) in the surface treatment agent, and 2 to 15%. More preferably by mass. When the content is 0.5% by mass or more, the tension pad resistance is sufficiently improved, and when the content is 20% by mass or less, the adhesive property to the anaerobic acrylic adhesive is not deteriorated.

In the surface treatment agent used in the present embodiment, the components other than water are preferably composed of the above (A) to (D) or the above (A) to (E), but if necessary, other components may be added to the surface. It may be contained in an amount of 5% by mass or less with respect to the total mass of (A) to (E) in the treatment agent. When the surface treatment agent does not contain the lubricant (E), the content means the content of (A) to (D) with respect to the total mass. Examples of other components include alcohols, ketones, cellosolve-based water-soluble solvents, surfactants, defoamers, leveling agents, pH adjusters, antibacterial and antifungal agents, and the like. By adding these components, the dryness, coating appearance, workability, and designability of the surface treatment agent are improved.

The surface treatment agent used in this embodiment is obtained by mixing each of the above-mentioned components in water such as deionized water and distilled water. The ratio of the total mass of (A) to (E) in the surface treatment agent may be appropriately selected, but is preferably in the range of 2 to 16% by mass.

(Manufacturing method of electrical steel sheet with insulating film)
In the present embodiment, an insulating film is formed by applying a surface treatment agent to at least one surface of an electromagnetic steel sheet and heating and drying it. Examples of the method of applying the surface treatment agent to the electrical steel sheet include a roll coating method, a bar coating method, a dipping method, a spray coating method, and the like, and an optimum method is appropriately selected depending on the shape of the electrical steel sheet to be treated. More specifically, for example, if the electromagnetic steel sheet is in the form of a sheet, a roll coating method, a bar coating method, or a spray coating method can be selected. The spray coating method is a method in which a surface treatment agent is sprayed on an electromagnetic steel sheet and a roll squeezer or a gas is sprayed at high pressure to adjust the coating amount. If the electrical steel sheet is a molded product, a method of immersing it in a surface treatment agent and pulling it up, and in some cases, blowing off excess surface treatment agent with compressed air to adjust the coating amount, or the like is selected.

The heating temperature (maximum reached plate temperature) when the surface treatment agent applied to the surface of the electromagnetic steel sheet is heated and dried is usually 80 to 350 ° C., more preferably 100 to 300 ° C. When the heating temperature is 80 ° C. or higher, moisture, which is the main solvent, does not remain in the insulating film, so that the corrosion resistance does not deteriorate. Further, when the heating temperature is 350 ° C. or lower, the generation of cracks in the insulating coating is suppressed, so that the corrosion resistance does not deteriorate. Further, the optimum heating time is appropriately selected depending on the type of the electromagnetic steel sheet used and the like. From the viewpoint of productivity and the like, 0.1 to 60 seconds is preferable, and 1 to 30 seconds is more preferable.

The amount of the insulating coating adhered is not particularly limited, but is preferably about 0.05 to 5 g / m ² per side. The amount of adhesion, that is, the total solid content mass of the insulating film can be measured from the weight loss after the film is removed by alkali peeling. When the amount of adhesion is small, a standard sample having a known amount of adhesion measured by the alkaline stripping method can be measured from a calibration curve obtained by fluorescent X-ray analysis. If the adhesion amount is 0.05 g / m ² or more, corrosion resistance and insulation can be satisfied, while if it is 5 g / m ² or less, not only the film adhesion is improved, but also blisters occur during coating baking. It does not occur and does not cause deterioration of paintability. More preferably, it is 0.1 to 3.0 g / m ² . The insulating film is preferably formed on both sides of the electrical steel sheet, but depending on the purpose, only one side may be used, and the other side may be another insulating film.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

(1) Material A magnetic steel sheet [A230 (JIS C 2552 (2000))] having a plate thickness of 0.5 mm was used as a test material.

(2) Pretreatment (cleaning)
As a method for producing the test plate, first, the surface of the test material was treated with Palclean N364S manufactured by Nihon Parkerizing Co., Ltd. to remove oil and dirt on the surface. Next, after washing with tap water and confirming that the surface of the test material is 100% wet with water, further pour pure water (deionized water) and dry the water in an oven at 100 ° C. Used as a board.

(3) Surface treatment agent Each component was mixed in water with the composition (mass ratio) shown in Table 1 to obtain a surface treatment agent. The concentration of the total mass of the components (A) to (E) with respect to the surface treatment agent was 6.3 g / L. The compounds used in Table 1 will be described below.

[Trialkoxysilane / Dialkoxysilane (A)]
A1: Methyltrimethoxysilane A2: Didimethyldimethoxysilane

[Silane Coupling Agent (B)]
B1: 3-glycidoxypropyltrimethoxysilane B2: 3-aminopropyltrimethoxysilane B3: N- (aminoethyl) 3-aminopropyltrimethoxysilane

[Plate-shaped silica (C)]
C1: Average particle diameter 0.2 μm, aspect ratio 20
C2: Average particle diameter 0.5 μm, aspect ratio 50
C3: Average particle diameter 0.1 μm, aspect ratio 10

[Urethane resin (D)]
D1: Polyether-based urethane resin (weight average molecular weight: 7500)
D2: Polyester urethane resin (weight average molecular weight: 700,000)
D3: Polyester urethane resin (weight average molecular weight: 200,000)
D4: Polyester urethane resin (weight average molecular weight: 500,000)
D5: Polycarbonate urethane resin (weight average molecular weight: 500000)

[Lubricant (E)]
E1: Polyethylene wax (Chemipearl 900)

(4) Treatment method After annealing to obtain a predetermined material in a continuous annealing line, a surface treatment agent is applied by roll coater coating when the steel sheet is cooled, and the maximum plate temperature reached in the oven is 200. It was dried at ° C. to form an insulating film having a film adhesion amount of 0.5 g / m ² on both sides. As the roll coater condition, a full reverse method was adopted with 3 rolls. The drying temperature indicates the temperature reached on the surface of the test plate.

(5) Evaluation [Adhesive characteristics]
The size of the test piece for adhesive strength evaluation was 25 mm × 100 mm, and a shear tensile test piece was prepared according to DIN EN 1465 (2009-07), and a shear tensile test was carried out. Specifically, the insulating coatings of the two test pieces are adhered to each other via an adhesive, a tensile load is applied in a direction parallel to the adhesive surface, and the maximum load when the adhesive surface is broken is the adhesive area. The tensile shear strength was obtained by dividing by. As the adhesive, an anaerobic acrylic adhesive AS5334 manufactured by Asek Co., Ltd. was used, and as an activator, AS8000 manufactured by Asek Co., Ltd. was used. The tensile shear strength was evaluated according to the following criteria. The results are shown in Table 1. If it is ◎ or ○, it is considered as a pass.
(criterion)
⊚: 8 MPa or more ○: 5 MPa or more and less than 8 MPa ×: less than 5 MPa

[Corrosion resistance]
Two test materials punched out to 50 mm × 50 mm were stacked, and 200 g of a weight was placed on the test material and left in a constant temperature and humidity chamber at 50 ° C. and a relative humidity of 80% for 2 weeks. The average rust-generated area ratio of the two superposed surfaces was visually measured. The results are shown in Table 1. If it is ◎ or ○, it is considered as a pass.
(criterion)
◎: 0%
◯: More than 0% and less than 5% ×: 5% or more

[Tension pad resistance]
Using a tension pad having an area of 10 mm × 10 mm, a load of 19.6 N (2.0 kgf) was applied by a rubbing tester manufactured by Taihei Rika Kogyo Co., Ltd., and the surface of the insulating coating was rubbed 100 times back and forth. The amount of adhesion between the rubbed portion and its vicinity was measured, and the residual ratio of the insulating film after 100 round trips was calculated. The amount of adhesion was determined from the calibration curve obtained by measuring the fluorescent X-ray intensity of Si and using a standard plate having a known amount of adhesion. The results are shown in Table 1. If it is ◎ or ○, it is considered as a pass.
(criterion)
⊚: 90% or more ○: 70% or more and less than 90% ×: less than 70%

The electromagnetic steel sheet with an insulating coating of the present invention is excellent in adhesive strength, corrosion resistance, and tension pad resistance against anaerobic acrylic adhesives, and is therefore suitable as a material for iron cores of automobile motors and electrical equipment. be.

Claims (2)

Substituents other than the alkoxy group bonded to Si are trialkoxysilane and / or dialkoxysilane (A) consisting of only at least one non-reactive substituent selected from hydrogen, alkyl group, and phenyl group.
Silane coupling agent (B) and
Plate-shaped silica (C) having an average particle size of 0.08 to 0.9 μm and an aspect ratio of 10 to 100,
Urethane resin (D) and
water and,
An electromagnetic steel sheet with an insulating coating having an insulating coating obtained by applying a surface treatment agent containing the following conditions (1) to (3) to at least one surface of the electrical steel sheet and drying the steel sheet.
(1) The mass ratio (A / B) of the trialkoxysilane and / or the dialkoxysilane (A) to the silane coupling agent (B) is 0.05 to 1.00.
(2) The content of the plate-shaped silica (C) is 2 to 30% by mass with respect to the total mass of (A) to (D) in the surface treatment agent.
(3) The content of the urethane resin (D) is 2 to 30% by mass with respect to the total mass of (A) to (D) in the surface treatment agent. Substituents other than the alkoxy group bonded to Si are trialkoxysilane and / or dialkoxysilane (A) consisting of only at least one non-reactive substituent selected from hydrogen, alkyl group, and phenyl group.
Silane coupling agent (B) and
Plate-shaped silica (C) having an average particle size of 0.08 to 0.9 μm and an aspect ratio of 10 to 100,
Urethane resin (D) and
Lubricant (E) and
water and,
An electromagnetic steel sheet with an insulating film having an insulating film obtained by applying a surface treatment agent containing the above conditions (1) to (4) so as to satisfy the following conditions (1) to (4) on at least one surface of the electrical steel sheet and drying it.
(1) The mass ratio (A / B) of the trialkoxysilane and / or the dialkoxysilane (A) to the silane coupling agent (B) is 0.05 to 1.00.
(2) The content of the plate-shaped silica (C) is 2 to 30% by mass with respect to the total mass of (A) to (E) in the surface treatment agent.
(3) The content of the urethane resin (D) is 2 to 30% by mass with respect to the total mass of (A) to (E) in the surface treatment agent.
(4) The content of the lubricant (E) is 0.5 to 20% by mass with respect to the total mass of (A) to (E) in the surface treatment agent.