JPH07272916A - Electromagnetic steel plate having insulating film excellent in automatic stacking property, and its manufacture - Google Patents

Abstract

PURPOSE:To provide an electromagnetic steel plate, which has an insulating film excellent in automatic stacking property, and its manufacture which can speed up the processing and assembling work of a stacked core by solving the stop trouble of an automatic stacker for a stacked iron core. CONSTITUTION:Processing liquid, where organic resin particles 2-40mum in diameter are added by 0.1-10wt.% to the liquid containing at least hexavalent chromium compound, a reducer, and organic resin and the surface tension is 15-40dyne/cm, and the ratio of viscosity to surface tension is 0.02-0.20s/cm, is applied and baked with a roller coater. An electromagnetic steel plate, which has, on its surface, an insulating film A where projection bands 5 in each of which projections 4 1-20mum in height D by organic resin particles are distributed 800-5000 pieces/mm<2> in width of 0.5-1.0mm and flat bands 6 in each of which projections 4 are distributed 300 pieces/mm<2> or under in width of the 0.1-2.0mm are drawn up in rows in parallel with the direction of rolling and besides alternately on an insulating layer 2, is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic steel sheet having an insulating film excellent in automatic laminating property of a laminated iron core made of an electromagnetic steel sheet, and a method for producing the same.

[0002]

2. Description of the Related Art Magnetic steel sheets are widely used as iron core materials for motors and transformers, and in particular, iron cores for small transformers for household electric appliances are usually made of laminated steel sheets. It is used after being processed into a core or rolled iron core. Among them, the laminated iron core is made by continuously punching electromagnetic steel sheets into a core having a predetermined shape, appropriately annealing and then laminating and fixing. Therefore, as the characteristics of the insulating film on the surface of the electromagnetic steel sheet, not only the interlayer insulation resistance but also punching property, corrosion resistance, adhesion to the steel plate, and strain relief annealing resistance are required to be excellent. Further, in the case of stacking and fixing, it is required that the gas generated when the end faces of the steel plates after the stacking are TIG-welded be released from the welded portion (no blowhole is generated), that is, weldability. Further, durability against refrigerant, insulating oil, etc. may be required.

In recent years, new characteristics have begun to be demanded in addition to the conventional characteristics as the iron core processing technology is automated and speeded up. Magnetic steel sheets for laminated iron cores must be able to withstand high-speed laminating work (core filling work) using automatic laminating equipment.
However, when a magnetic steel sheet is laminated by an automatic laminating device, a local portion of the core often catches when the core is slid, causing a work trouble of stopping the automatic laminating device. Therefore, it has been desired to develop a magnetic steel sheet which is free from such troubles and has excellent automatic laminating properties.

As a conventional technique relating to the insulating coating of electromagnetic steel sheets, the punchability is remarkably improved by adding an organic substance to the insulating coating, but the above-mentioned weldability for fixing the laminate after punching is not excellent, and this is improved. As a technique for doing so, for example, Japanese Patent Publication No. Sho 49-19078 discloses a method in which organic particles of about 2 μm or more are added to a treatment liquid and the resultant is applied and baked on a steel sheet. However, simply adding the organic particles has a problem in the dispersibility of the particles and the adhesion to the steel sheet.
Japanese Patent Publication No. 55-21111 discloses that organic resin particles are added to an emulsion resin solution in advance and uniformly dispersed, and then a treatment liquid mixed with a phosphoric acid-based or chromic acid-based solution is applied and baked on a steel plate surface. , Part of the organic resin particles are melted to improve the adhesive strength, and the surface roughness is 2-10.
Weldability was secured by forming an insulating film of μm. However, in the above method, the dispersed state of the organic resin particles in the treatment liquid is not perfect, and a part of the organic resin particles is melted at the time of baking after applying the treatment liquid to improve the adhesion to the steel sheet. However, the particles deformed due to bumping from the particles, which left a problem in punchability. JP-B-62-25750 discloses, in order to solve the above problems, a mixed solution of an aqueous dichromate solution, an organic resin emulsion and a reducing agent, and a polyethylene powder resin dispersed in water with a surfactant. By coating and baking the treated treatment liquid on an electromagnetic steel sheet, the adhesion to the steel sheet is improved by the uniform dispersion of particles and the formation of a film having a suitable surface roughness,
Weldability and punchability were improved at the same time.

As described above, as a method for forming an insulating coating on which the organic resin particles are present on the surface of the electromagnetic steel sheet, the organic resin particles are added to the treatment liquid containing a hexavalent chromium compound, a reducing agent and the organic resin as main components. A technique for producing a magnetic steel sheet having a desired insulating film formed on the surface by applying the treatment liquid obtained by addition to the surface of the magnetic steel sheet by a roll coater and then baking the applied treatment liquid. Is listed. However, none of these inventions was made from the viewpoint of improving the automatic laminating property, and the purpose of imparting appropriate roughness to the surface of the electromagnetic steel sheet was to aim at improving the weldability. Therefore, the high-speed automatic laminating work (core filling work) cannot be improved. Furthermore,
As an invention aimed at improving weldability, for example, Japanese Patent Laid-Open No.
There is a 2-148703 publication (hereinafter referred to as prior art 1). Prior art 1 describes an electromagnetic steel sheet in which a steel sheet having protrusions or ridges formed on the surface so as not to form a blocking plane portion is manufactured, and an insulating film containing an organic resin is formed on the surface of the steel sheet. However, regarding the improvement of high-speed automatic laminating workability, the problem has not been solved as in the above-mentioned prior art.

[0006]

In order to solve the above-mentioned problems, a suitable state of forming an insulating film is found in order to reduce the contact resistance of the surface of the electromagnetic steel sheet when the core slides in the automatic laminating apparatus. The purpose is to find out the preparation conditions for forming such an insulating film on the surface of a magnetic steel sheet, and to invent a technique capable of industrializing it.

Therefore, an object of the present invention is to solve the above-mentioned problems and solve the trouble of stopping the automatic laminating apparatus in the automatic laminating work (core filling work) of the electromagnetic steel sheets for the laminated iron core, and An object of the present invention is to provide an electromagnetic steel sheet having an insulating film excellent in automatic laminating property and capable of increasing the processing and assembling work speed, and a manufacturing method thereof.

[0008]

In carrying out automatic laminating work, the above-mentioned problems are solved by paying attention to the fact that the sliding direction of the core and the rolling direction of the electromagnetic steel sheet are parallel to each other.
The following inventions that can achieve the object of the present invention have been completed.

The electromagnetic steel sheet having an insulating film excellent in automatic laminating property of the present invention is an electromagnetic steel sheet having an insulating film consisting of a projection band and a flat band on the surface, wherein the projection band and the flat band are , The magnetic steel sheets are formed in parallel and alternately in parallel with the rolling direction, and the protrusion bands are 0.5
Protrusions with a width in the range of ~ 1.0 mm and a rise height of organic resin particles in the range of 1 to 20 μm are distributed on the surface within a number density of 800 to 5000 / mm ^2. The flat band has a width in the range of 0.1 to 2.0 mm, and the protrusions are distributed on the surface within a number density of 300 / mm ² or less. It is a thing.

Further, according to the present invention, there is provided a method for producing an electromagnetic steel sheet having an insulating film excellent in automatic laminating property, wherein a treatment liquid containing at least a hexavalent chromium compound, a reducing agent and an organic resin is used as a roll coater. Surface of electrical steel sheet and /
Alternatively, in a method for producing an electromagnetic steel sheet in which an insulating film is formed on the front surface and / or the back surface of the electromagnetic steel sheet by applying the treatment liquid to the front surface and / or the back surface of the electromagnetic steel sheet, 2-40
containing 0.1 to 10 wt.% of organic resin particles within the range of μm,
Treatment liquid viscosity a (cps), treatment liquid surface tension b (dyne / cm)
, The moving speed V _S (m / min) of the steel plate and the peripheral speed V _A (m / min) of the applicator roll are expressed by the following formulas (1) to (3): 15 ≤ b ≤ 40 ─── (1 ) 0.02 meet ≦ a / b ≦ 0.20 ─── ( 2) 0.85 ≦ a (V S + V a) /2b≦9.00 ─── (3), and, applique - tallow - le is Furattoro - a Le b -Using a coater and applying it to the steel sheet in a reversal method, and then applying to the surface of the electromagnetic steel sheet and / or
Alternatively, it is characterized by baking the treatment liquid applied on the back surface.

FIG. 1 is an explanatory view of a state of formation of an insulating film formed on the surface of an electromagnetic steel sheet by the method of the present invention. As is clear from the figure, the insulating coating A 1 is formed on the surface of the electromagnetic steel sheet 1. Insulation film A
Is composed of the insulating layer 2 and a portion that is raised by the organic resin particles 3 and is raised above the surface of the insulating layer 2 (referred to as a protrusion 4 in the present invention). The projection strips 5 having the projections 4 densely distributed and the flat strips 6 having the projections 4 roughly distributed are the electromagnetic steel sheet.
It is formed on the surface of the insulating layer 2 in a state of being formed in parallel with and alternating with the rolling direction of 1. B in the figure,
C and D are the width of the protruding strip 5 and the flat strip, respectively.
The width of 6 and the height of the protrusion are shown.

[0012]

The present invention will be described in detail below, and the reasons for limiting the state of formation of the insulating film will be described.

(1) Width of protrusion band and width of flat band:
It is a graph which shows the influence of the width | variety of the protrusion band of an insulating film, and the width of a flat band on the automatic lamination property of a laminated iron core. Plot symbols ◯, Δ, and × in the figure represent the quality of the automatic stacking property.
The test method for automatic laminating property and the definitions of ◯, Δ, and × are as described later in this specification (◯: excellent, Δ: somewhat bad, ×: bad). As is clear from the figure, the range of the width B of the protruding band and the width C of the flat band, which are excellent in the automatic laminating property, is within the range of the diagonal line indicated by the symbol E. The figure shows a case where the projection bands C and the flat bands D are alternately arranged in parallel and are formed in parallel to the rolling direction of the electromagnetic steel sheet.

Therefore, in order to obtain excellent automatic laminating property,
The width B of the ridges should be in the range 0.5-1.0 mm, and the width C of the flat bands should be limited to the range 0.1-2.0 mm.
The figure is obtained from the experimental results under the following conditions. Electrical steel sheet: Thickness = 0.5 mm, steel type = Si content 0.35 wt.% Non-oriented electrical steel sheet, number of protrusions with height of 1 to 7 μm distributed on protrusion band: 1200 to 27
00 pieces / in the range of mm ^2, the number of height 1 to 7-[mu] m of projections distributed in a flat band: 120-2
Within the range of 60 pieces / mm ² , core: punched into 66 mm E type and I type, automatic stacking insertion device: Model OEI- made by Aoki Automatic Co., Ltd.
SD-66mmXT Automatic laminating work and evaluation of automatic laminating property: The cores punched into the E-shape and I-shape were slid in the longitudinal direction of the projecting strips, and each occurred during the automatic laminating work of 1000 sheets. Number of device stops. No equipment outage occurred. : Are better. → O, the machine stopped 1 to 3 times. : Somewhat bad. → △
Mark, the equipment has been stopped more than 4 times. : Bad. → ×
mark.

(2) Height of protrusions: The protrusions formed by the organic resin particles reduce the frictional resistance on the surface of the insulating coated steel sheet, facilitate the sliding of the core, and improve the automatic laminating property. If the height of the protrusion is less than 1 μm, the effect of reducing frictional resistance is lost. However, if the height of the protrusion exceeds 20 μm, the frictional resistance increases, the automatic laminating property deteriorates, and the space factor and the adhesion of the insulating film decrease. Therefore, of the protrusions formed by the organic resin particles distributed in the protrusion band and the flat band, the height of the protrusion for improving the automatic laminating property is 1 to 20 μm.
Should be limited to within the range.

(3) The number of protrusions distributed in the protrusion band, and
Number of protrusions with a height of 1 to 7 μm distributed in the flat band: It is effective to have protrusions with a height of 1 to 20 μm distributed in the protrusion band in order to obtain sufficient automatic laminating property. 800 pieces / m
If it is less than m ² , a sufficient effect cannot be obtained. However, even if the number exceeds 5000 pieces / mm ² , the automatic laminating property has no further improvement effect, while the adhesiveness of the insulating film decreases. Therefore, the height distributed in the protrusion band is 1 ~
The number of 20 μm protrusions should be limited to the range of 800-5000 protrusions / mm ² . 300 flat protrusions with a height of 1 to 20 μm
If the number of particles is more than 1 / mm ² , the effect of improving the automatic laminating property by the protrusions distributed in the protrusion band is hindered. Therefore, the number of protrusions with a height of 1 to 7 μm distributed in the flat belt is 300 / m.
It should be limited to m ² or less.

(4) Forming direction of protrusion band and flat band: The direction of sliding the core is the same as the rolling direction of the magnetic steel sheet. On the other hand, in the automatic laminating operation, the catching of the core is improved by making the longitudinal forming direction of the protruding band and the flat band coincide with the sliding direction of the core. Therefore, the forming direction of the protrusion band and the flat band should be the same as the rolling direction of the electrical steel sheet.

Next, a method of manufacturing an electromagnetic steel sheet having an insulating film having the above-mentioned characteristics and excellent in automatic laminating property will be described. The production method of the present invention is a process liquid containing a hexavalent chromium compound, a reducing agent and an organic resin as a main component (hereinafter referred to as a basic process liquid), to which a treatment liquid obtained by adding organic resin particles is added. It is a method of producing a magnetic steel sheet having a desired insulating film formed on the surface by applying the treatment liquid applied on the surface of a magnetic steel sheet with a rucotor, and then baking the applied treatment liquid. The method and the method of baking the applied processing liquid are limited.

(1) Surface tension of treatment liquid and ratio of viscosity of treatment liquid to surface tension of treatment liquid: The surface tension of treatment liquid and the viscosity of treatment liquid are variously changed, and the electromagnetic steel sheet is prepared by the method described later. Experiments were conducted on the success or failure of the formation of the protrusion band 5 on the surface of the insulating film A formed on the surface of 1, and from the results,
The manufacturing conditions were limited as follows.

When the surface tension of the treatment liquid is less than 15 dyne / cm, the treatment liquid foams on the roll coater, and the bubbles are transferred onto the magnetic steel sheet 1 and the projection band 5 is not formed. So it should be more than 15dyne / cm. However, if the surface tension exceeds 40 dyne / cm, electrical steel sheet 1
The treatment liquid applied to the substrate is repelled, and the projection band 5 is not formed. Therefore, the surface tension of the treatment liquid is 15-40 dyne / c.
Should be in the range of m.

FIG. 3 is a graph showing the effect of the ratio of the viscosity of the treatment liquid and the surface tension on the width of the flat band on the surface of the insulating film. However, in the figure, the surface tension is 15 to 40 dyne / c.
It is in the range of m. As is clear from the figure, the width 6 of the flat band is within the range of 0.1 to 2.0 mm of the present invention because the ratio of the viscosity of the treatment liquid to the surface tension is 0.02 to 0.20 s / cm.
It is within the range of. Therefore, the ratio of viscosity to surface tension should be 0.02-0.20. That is, when the viscosity of the treatment liquid is represented by a (cps) and the surface tension is represented by b (dyne / cm), the treatment liquid should satisfy the following equations (1) and (2). 15 ≤ b ≤ 40 ── (1) 0.02 ≤ a / b ≤ 0.20 ── (2)

The above experimental conditions are as follows. Regarding the properties of the treatment liquid, the treatment liquid composition: CaCr ₂ O ₇ = 256 parts by weight, sucrose = 35 parts by weight,
Acrylic resin emulsion (solid content 20%) = 120 parts by weight,
Polyethylene powder (particle size 12 μm = 1 part by weight, water = 1168
Parts by weight, thickener: fermented polysaccharide, surfactant: nonionic fluorosurfactant, (a small amount of thickener and surfactant is added to the treatment liquid) Viscosity and surface tension measurement temperature: 20 ° C For the coating method and baking method of the treatment liquid, roll roller applicator roll: flat roll
Rotating method of application and application rolls: reversing method with respect to the moving direction of electromagnetic steel sheet, baking method: radiant tube method 40 seconds at electromagnetic steel sheet temperature 300 ° C in a heating furnace.

(2) Method of applying treatment liquid: When a treatment liquid having physical properties satisfying the above formulas (1) and (2) is used as an application roll, a gluing roll or a gravure roll is used. The organic resin particles clog the recesses on the surface of the roll, thus hindering the formation of the projection band. Therefore, flat rolls should be used. When the application roll is rotated in the natural direction with respect to the moving direction of the magnetic steel sheet, the application roll
At the boundary between the roll and the electromagnetic steel plate, the treatment liquid foams and is transferred to the steel plate, and no protruding band is formed. Therefore, the reverse direction should be applied in the moving direction of the electromagnetic steel sheet.

[0024] (3) the physical properties of the treatment liquid, the electrical steel sheet moving speed and applique - tallow - Le peripheral speed relationships: the moving speed of the electrical steel sheet V _S (m / min), applique - tallow - peripheral speed of the Le To V _A
Expressed in (m / min), the following equation _{(3): 0.85 ≦ a (V S +} V A) / 2b ≦ 9.00 ─── (3) so as to satisfy the movement of the electrical steel sheet speed and applique - tallow - When the peripheral speed of the
Within the range of up to 1.0 mm, if the formula (3) is not satisfied, the width of the protrusion band is outside the range of 0.5 to 1.0 mm, and the characteristics excellent in automatic laminating property, which is the object of the present invention, cannot be obtained. . Therefore, the relationship of the above equation (3) should be satisfied among the physical properties of the treatment liquid, the moving speed of the electromagnetic steel plate, and the peripheral speed of the applicator roll.

(4) Particle size of organic resin particles: The organic resin particles in the insulating film give an uneven shape to the surface of the electromagnetic steel sheet and have a height of
The protrusions of 1 to 20 μm made of organic resin particles serve to improve the automatic laminating property by reducing the contact area of the surface of the electromagnetic steel sheet. If the particle size of the organic resin particles before addition to the basic treatment liquid is less than 2 μm, the maximum height of the protrusions after forming the insulating film will be less than 1 μm, while if it exceeds 40 μm, the height of the protrusions will increase. Since it exceeds 20 μm, an insulating film having protrusions having a height within the range of the present invention cannot be obtained, and sufficient automatic laminating property cannot be obtained. Therefore, the particle size of the organic resin particles before addition to the basic processing liquid should be within the range of 2 to 40 μm.

(5) Addition amount of organic resin particles: If the addition amount of organic resin particles is less than 0.1 wt.
The number of protrusions distributed in the protrusion band is less than 800 pieces / mm ² ,
On the other hand, when it exceeds 10 wt.%, The number of protrusions distributed in the protrusion band is
The number of protrusions exceeding 5000 / mm ² and distributed in the flat band
Beyond 300 pcs / mm ² , the number of protrusions within the scope of the invention can be exceeded. Therefore, the addition amount of the organic resin particles should be 0.1 to 10 wt.% With respect to the basic processing liquid.

The organic resin particles have a chemical composition of a polymer containing at least one selected from acrylic acid and its ester, methacrylic acid and its ester, ethylene, styrene, vinyl acetate and vinyltoluene as a monomer. There is no particular limitation as long as it does not impair the insulating property, such as particles and / or copolymer particles. As a method for adding the organic resin particles, powdery ones may be directly added, or ones previously dispersed or suspended in water may be added. Further, a dispersant or the like may be added as appropriate in order to stably maintain the dispersed state of the organic resin particles in the treatment liquid. In addition, in order to improve interlayer insulation resistance and heat resistance, silica sol, oxide sol such as alumina,
Alternatively, an inorganic substance such as phosphate or boric acid may be added to the treatment liquid.

(6) Chemical composition of treatment liquid: As a hexavalent chromium compound, it must react with a reducing agent during baking to form a trivalent chromium compound to form an insoluble insulating film. . For example, chromic anhydride, divalent or trivalent metal chromate, dichromate, divalent or trivalent metal oxide in chromic anhydride,
You may use at least 1 sort (s) selected from what melt | dissolved the hydroxide or carbonate.

The reducing agent reduces the hexavalent chromium compound to form an insoluble insulating film. Examples of the reducing agent include polyglycols such as glycerin, ethylene glycol, polyethylene glycol and sucrose, Alternatively, carboxylic acids such as succinic acid and adipic acid may be used. The addition amount of Cr is 6
10 to 50 parts by weight is desirable for 100 parts by weight of O ₃ .

The organic resin is for imparting punchability to the insulating film, is excellent in compatibility with the hexavalent chromium compound, and is uniformly dispersed or dissolved in the treatment liquid. Should be something. As such, organic resin emulsions and / or water-soluble organic resins are recommended. As the organic resin emulsion, at least one selected from acrylic acid and its ester, methacrylic acid and its ester, maleic acid, itaconic acid, styrene, vinyltoluene, vinyl acetate, acrylonitrile and acrylamide is used as a monomer. An emulsion of a polymer or copolymer obtained by an emulsion polymerization method or a suspension polymerization method, or an emulsion of a phenol resin, an alkyd resin, a polyester resin, or the like can be used. As the water-soluble organic resin, a water-soluble phenol resin, epoxy resin, alkyd resin, polyester resin or the like can be used. The amount of the organic resin added is preferably 5 to 100 parts by weight as a resin component with respect to 100 parts by weight of CrO ₃ equivalent of the hexavalent chromium compound. This is because if the amount is less than 5 parts by weight, sufficient punchability cannot be obtained, whereas if the amount exceeds 100 parts by weight, the adhesion of the insulating coating decreases.

In order to control the values of the surface tension and the viscosity / surface tension of the basic processing liquid within the ranges described above, a thickener and / or a surfactant can be added to the basic processing liquid as appropriate.

The amount of the insulating film formed is preferably 0.5 g / m ² or more in order to secure punchability and corrosion resistance. However, if it exceeds 5 g / m ² , the adhesion of the insulating film to the steel plate will be reduced. Therefore, it is desirable that the amount of the insulating film formed is in the range of 0.5 to 5 g / m ² .

The method of baking the insulating film is not particularly limited, and, for example, a radiant tube method, an induction method or the like can be used. Further, when the steel plate temperature during baking is 400 ° C or higher, the organic resin in the insulating film undergoes thermal decomposition, resulting in a decrease in punchability and corrosion resistance. Therefore, it is desirable that the temperature of the steel sheet during baking is 400 ° C or lower.

[0034]

EXAMPLES Next, the present invention will be described in more detail by way of examples and comparison with comparative examples. (Example 1) Table 1 shows the chemical composition of the basic treatment liquid (A, B, C) containing a hexavalent chromium compound, a reducing agent and an organic resin as main components.

[0035]

[Table 1]

Nos. 1 to 4 of the present invention and Nos. 1 to 4 of the comparative example were prepared by adding a predetermined amount of polymethylmethacrylate particles or polystyrene particles to the basic treatment liquid A or B, respectively. Prepared. Further, as a comparative example, No. 9 containing no organic resin particles was added.

Table 2 summarizes the manufacturing conditions for the insulating coatings of the present invention and comparative examples.

[0038]

[Table 2]

The addition weight ratio of organic resin particles (hereinafter referred to as addition wt.% Of organic resin particles) is shown in the same table. For all of the present invention examples and comparative examples, a small amount of thickener (Daiichi Kogyo Seiyaku Co., Ltd., DK-Rhamzan) and surfactant (Sumitomo 3M Co., Ltd., Florade FC-170) Viscosity (η) = 5 centipoise (c
ps), surface tension (σ) = 31dyne / cm, η / σ = 0.16s / cm
Was prepared. The treatment liquid was applied to the surface of a non-oriented silicon steel sheet (Si content = 0.3%) with a thickness of 0.6 mm by a roll coater (
Using a flat roll as an applicator roll), the steel sheet is coated by a reversal method, and then the steel sheet temperature: 280 ° C. for 30 seconds in a radiant tube heating furnace. The liquid was baked.

Table 3 shows the formation state of the insulating film formed on the surface of the steel sheet and the quality of the automatic laminating property.

[0041]

[Table 3]

As is apparent from Tables 1, 2 and 3, the magnetic steel sheet of the present invention having the insulating coating formed on the surface thereof was prepared by the method of the present invention, and moreover, it has a self-lamination property of the core. It turns out to be excellent. On the other hand, the magnetic steel sheet having an insulating coating formed on its surface by a method outside the scope of the method of the present invention is inferior or slightly inferior in automatic laminating property of the core.

(Example 2) Basic treatment liquid (C) shown in Table 1
2 wt.% Polyethylene powder with a particle size of 15 μm was added to
Furthermore, by adding the same thickeners and surfactants used in Example 1, the surface tension and viscosity /
The treatment liquid was prepared by changing the value of the surface tension variously. Nos. 11 to 13 of the examples of the present invention, in which all the conditions of the treatment liquid and the coating method of the treatment liquid are within the scope of the present invention.
And, even if any one of the above-mentioned conditions is outside the scope of the present invention, the electrical steel sheet temperature: 280 ° C. for 30 seconds in the heating furnace of the radiant tube type, the treatment liquid. Was baked.

Table 4 summarizes the conditions for producing the insulating film for the above-mentioned inventive examples and comparative examples.

[0045]

[Table 4]

Table 5 shows the state of formation of the insulating film formed on the surface of the magnetic steel sheet and the result of determination of the quality of the automatic laminating property according to the examples of the present invention and the comparative examples shown in Table 4.

[0047]

[Table 5]

As is clear from Tables 1, 4 and 5, the magnetic steel sheet of the present invention having the insulating coating formed on the surface thereof was prepared by the method of the present invention, and it was found that the self-laminatability of the core was improved. It turns out to be excellent. On the other hand, the magnetic steel sheet having an insulating coating formed on its surface by a method outside the scope of the method of the present invention is inferior or slightly inferior in automatic laminating property of the core.

[0049]

As described above, according to the present invention,
By reducing the surface contact resistance between the insulating films formed on the surface of the electromagnetic steel sheet, when laminating the laminated iron core of the electromagnetic steel sheet with the automatic laminating device, the local part of the core causes a catch when sliding the core. As a result, troubles such as stopping the automatic laminating device are solved, and as a result, the speed of the work of assembling and assembling the laminated iron core can be increased.
Industrially useful effects are provided.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a state of formation of an insulating film formed on a surface of an electromagnetic steel sheet according to the present invention.

FIG. 2 is a graph showing the influence of the width of the protrusion band and the width of the flat band on the surface of the insulating film on the automatic laminating property of the laminated iron core.

FIG. 3 is a graph showing the effect of the ratio of the viscosity of the treatment liquid and the surface tension on the width of the flat band on the surface of the insulating film.

[Explanation of sign]

 1 Electromagnetic steel sheet, 2 Insulating layer, 3 Organic resin particles, 4 Protrusions by organic resin particles, 5 Protrusion strips, 6 Flat strips, A Insulating film, B Protrusion strip width, C Flat strip width, D Protrusions by organic resin particles The height of the E range is excellent for automatic laminating.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C23C 22/00 B (72) Inventor Masaaki Yamashita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihonhon Inside Steel Pipe Co., Ltd.

Claims (2)

[Claims] 1. A magnetic steel sheet having on its surface an insulating coating composed of a projection band and a flat band, wherein the projection band and the flat band are formed in parallel and alternately in parallel with a rolling direction of the electromagnetic steel plate. In addition, the protrusion band has a width within the range of 0.5 to 1.0 mm, and the height of the swelling due to the organic resin particles is 1 to 20 μm on the surface thereof.
The number of the protrusions is within the range of 800 to 5000 pieces / mm ² in number density, and the flat band has a width within the range of 0.1 to 2.0 mm, and the surface thereof has A magnetic steel sheet having an insulating coating excellent in automatic laminating property, characterized in that the projections are distributed within a number density of 300 pieces / mm ² or less. 2. A treatment liquid containing at least a hexavalent chromium compound, a reducing agent and an organic resin is applied to the front surface and / or the back surface of an electromagnetic steel sheet using a roll coater, and then the treatment liquid is used. In the method for producing an electromagnetic steel sheet, wherein an insulating coating is formed on the front surface and / or the back surface of the electromagnetic steel sheet by baking on the surface and / or the back surface of the electromagnetic steel sheet, organic resin particles having a particle diameter in the range of 2 to 40 μm. To 0.1
Containing 10 to 10 wt.%, The viscosity of the treatment liquid a (cps), the surface tension of the treatment liquid b (dyne / cm), the moving speed V _{S of the} steel sheet (m / min) and the peripheral speed V _A of the applicator roll ( m / min) is from (1) to
(3) Formula: 15 ≤ b ≤ 40 ─── (1) 0.02 ≤ a / b ≤ 0.20 ─── (2) 0.85 ≤ a (V _S + V _A ) / 2b ≤ 9.00 ─── (3) In addition, a roll coater whose applicator roll is a flat roll is used, and the applicator roll is applied to the steel plate by a reversal method, and then the surface of the electromagnetic steel plate and / or
Alternatively, a method for producing an electromagnetic steel sheet having an insulating film excellent in automatic laminating property is characterized by baking the treatment liquid applied on the back surface.