JP5471849B2 - Electrical steel sheet and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electrical steel sheet used as an iron core material for electrical equipment, for example, and a manufacturing method thereof, and more particularly to an electrical steel sheet having an insulating coating that has good workability and does not contain chromic acid, and a manufacturing method thereof.

When manufacturing motors and transformers, a hoop-shaped electrical steel sheet is punched into a predetermined shape, laminated and fixed to form an iron core, and then a copper wire is wound around teeth and then impregnated into a varnish. Or after spraying powder paint and baking and drying, attach terminals, flanges, bearings, etc. for connecting copper wires and fix them to the case.

  High efficiency and downsizing of electrical equipment have been strongly demanded in recent years from the viewpoint of global environmental conservation and from the viewpoint of global power and energy saving. Various measures are required to improve the efficiency and miniaturization of electrical equipment, but also improve the magnetic properties and workability of electrical steel sheets used as iron cores for motor iron cores and small transformers. Etc. are demanded.

  In order to increase the efficiency and miniaturization of electrical equipment, it is important to improve the machining accuracy by accurately controlling the gap between the rotor and the stator. Measures have been taken to use or devise the mold shape.

  Originally, the smaller the gap between the stator and rotor of the motor, the greater the electromagnetic force and the greater the rotational torque of the motor. However, if the gap is made too small, the rotor and stator will rub against each other or there will be minute foreign matter. It is easy to get into trouble by biting it.

  Therefore, in order to manage the gap between the rotor and the stator with high accuracy, it is necessary to have good processing accuracy when processing the electromagnetic steel sheet into an iron core.

  On the other hand, an insulating coating is generally applied to the surface of a magnetic steel sheet used for the iron core of electrical equipment, and coating properties such as corrosion resistance, weldability, adhesion, and heat resistance are required in addition to insulation. It has been found that the iron core shape at the time of punching is also greatly affected by the insulating coating of the electromagnetic steel sheet.

  As an insulating film of such an electrical steel sheet, a mixture mainly composed of an inorganic acid salt such as chromate or phosphate and an organic resin is generally applied.

As a technique related to the insulating coating of an electrical steel sheet, in the past, the following Patent Document 1 uses a treatment liquid mainly composed of an organic resin emulsion such as dichromate, vinyl acetate, butadiene-styrene copolymer, and acrylic resin. A method for forming an insulating film is disclosed, and in Patent Document 2 below, a chromic acid aqueous solution, an emulsion type resin, and an organic reducing agent are mixed, and a readily soluble aluminum compound, a divalent metal oxide, and the like H ₃ BO ₃ , and the molar ratio of Me ²⁺ / Al ^{3+ in} the chromic acid solution is 0 to 7.0, and the molar ratio of (Al ³⁺ + Me ²⁺ ) / CrO ₃ is 0.2 to 0.5, H ₃ A technique for forming an insulating film using a treatment liquid having a BO ₃ / CrO ₃ molar ratio in the range of 0.1 to 1.5 is disclosed.

  Further, in Patent Document 3 below, particles of about 2 μm or more such as bakelite and melamine resin are further added to an inorganic organic mixed film in which an organic resin is mixed with an organic film-based or phosphoric acid-based or chromic acid-based inorganic component. A technique for adding and imparting surface roughness is disclosed.

  In recent years, the development of insulating coatings that do not use a chromic acid aqueous solution containing hexavalent chromium has been promoted due to an increase in awareness of environmental problems. As such a technique, the following Patent Document 4 includes a chromium compound by blending a specific ratio of a phosphate with a specific composition, boric acid and / or colloidal silica, and an organic resin emulsion having a specific particle size, and baking it onto a steel sheet. A processing method is described which has a coating property equivalent to that of an insulating coating containing a conventional chromium compound in a treatment solution containing no chromium, and retains excellent slipperiness after strain relief annealing.

  Moreover, in the following patent document 5, the technique regarding the insulating film comprised by the specific ratio of an ethylene- unsaturated carboxylic acid copolymer, an epoxy resin, a silane coupling agent, and a silica is disclosed.

  Regarding the processability of such an insulating coating containing no chromic acid, the following Patent Document 6 discloses a carbon 1 s peak and a phosphorus 2 s peak as measured by photoelectron spectroscopy with a metal phosphate and an organic resin as main components. In addition, a treatment liquid containing a specific amount of a water-soluble organic compound having a boiling point or sublimation point of 100 ° C. or higher is applied to a magnetic steel sheet in a treatment liquid mainly composed of a metal phosphate and an organic resin. A technique relating to excellent punching characteristics characterized by coating and baking is disclosed.

  In the field of surface-treated steel sheets, the following Patent Document 7 includes a modified fatty acid amide wax dispersion imparted with a polar group in addition to an aqueous resin, colloidal silica and water, and a modified polyolefin having a molecular weight of 700 to 3000 and an oxidation of 5 to 30. It is composed of at least one lubricant selected from wax dispersions, the colloidal silica content is 5 to 35% by weight in terms of solid content, and the lubricant content is 1 to 30% by weight in terms of solid content. A technique relating to a water-based organic composite paint characterized by the above is disclosed.

Japanese Patent Publication No. 50-15013 Japanese Patent Laid-Open No. 03-36284 Japanese Patent Publication No.49-19078 Japanese Patent Laid-Open No. 06-330338 JP 09-323066 A Japanese Patent Laid-Open No. 11-80971 JP 2001-288582 A

  Since the machining accuracy associated with such high efficiency and miniaturization of motors has become a problem, the punching accuracy of laminated iron cores has become important. In particular, so-called SPM motors, IPM motors, or AC servo motors that use magnets for the rotor have been developed recently, and there is an increasing demand for particularly strong torque, and improvements in the punching accuracy are required. However, there is a problem that the dimensional accuracy is poor in the punching workability of the insulating coating of the conventional electromagnetic steel sheet.

  In addition, the coating developed for the surface-treated steel sheet cannot obtain the film properties such as the space factor, adhesion and heat resistance required for the insulating film of the electromagnetic steel sheet, and cannot maintain the characteristics as the insulating film. There was a problem.

  Furthermore, even if the clearance of the punching die is improved to improve the processing accuracy, the wear of the die will be severe, and even if you try cutting after punching, the productivity will be reduced, and it will be time consuming and expensive. There was a problem that.

  Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to improve the punching workability of the electromagnetic steel sheet, and to prevent variations in processing accuracy caused when the electromagnetic steel sheet is punched. An object of the present invention is to provide an electrical steel sheet that can be reduced.

(1) One or two kinds of acrylic resin, epoxy resin, polyester resin, and urethane resin having 100 parts by mass of metal phosphate as the main component and an average particle size of 0.05 to 0.50 μm on the surface of the electrical steel sheet With respect to the binder composed of 1 to 50 parts by mass of the above mixture or copolymer, the fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is 0.3 to 5 with respect to 100 parts by mass of the solid content of the binder. An electrical steel sheet having an insulating coating mixed and dispersed by 0.0 part by mass.
(2) On the surface of the electrical steel sheet, 100 parts by mass of colloidal silica as a main component and one or more of acrylic resin, epoxy resin, polyester resin and urethane resin having an average particle size of 0.05 to 0.50 μm With respect to the binder composed of 40 to 400 parts by mass of the mixture or copolymer, the fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is 0.3 to 5.0 with respect to 100 parts by mass of the solid content of the binder. An electrical steel sheet comprising an insulating coating mixed and dispersed by mass.
(3) One or a mixture of two or more of acrylic resin, epoxy resin, polyester resin and urethane resin having an average particle diameter of 0.05 to 0.50 μm with respect to 100 parts by mass of the metal phosphate as a main component. After mixing 1-50 parts by mass of the polymer emulsion with a resin solid content, the fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is converted to the resin solid content with respect to 100 parts by mass of the solid content of the mixture. A method for producing an electrical steel sheet, comprising applying a treatment liquid mixed with 0.3 to 5.0 parts by mass to the surface of the electrical steel sheet and baking and drying at an ultimate temperature of 150 to 400 ° C for 5 to 30 seconds.
(4) One or a mixture or copolymer of acrylic resin, epoxy resin polyester resin and urethane resin having an average particle size of 0.05 to 0.50 μm with respect to 100 parts by mass of colloidal silica as a main component After the emulsion is mixed with 40 to 400 parts by mass of resin solid content, the fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is added to 100 parts by mass of the solid content of the binder with respect to 100 parts by mass of the solid content of the mixture. A method for producing an electrical steel sheet, comprising applying a treatment liquid mixed with 0.3 to 5.0 parts by mass to the surface of the electrical steel sheet and baking and drying at an ultimate temperature of 150 to 400 ° C for 5 to 30 seconds.

  As described above, the present invention provides an insulating coating composed of a specific proportion of a metal phosphate and a specific organic resin, or colloidal silica and a specific organic resin, and a specific fatty acid or a specific fatty acid salt. By forming on the surface, it is possible to improve the punchability of the electromagnetic steel sheet, and to obtain an electromagnetic steel sheet that retains the insulating coating properties necessary for the electromagnetic steel sheet and has good punchability.

Hereinafter, preferred embodiments of the present invention will be described in detail.
First, the non-oriented electrical steel sheet containing Si: 0.1 mass% or more and Al: 0.05 mass% or more is preferable as the electrical steel sheet used in the present embodiment. Si increases in electrical resistance and improves magnetic properties as the amount added increases, but at the same time brittleness increases, so less than 4.0 mass% is preferable. Similarly, when Al is added, the magnetic properties are improved, but the rolling property is lowered, so less than 3.0 mass% is preferable. In the electrical steel sheet used in this embodiment, in addition to Si and Al, Mn can be added in the range of 0.01 mass% to 1.0 mass%, and other typical elements such as S, N, and C are each less than 100 ppm. Preferably, it is less than 20 ppm.

  In this embodiment, the slab having the above steel components is heated to 1150 to 1250 ° C., hot-rolled and wound into a coil shape, and annealed in the range of 800 ° C. to 1050 ° C. in the state of a hot-rolled sheet as necessary. Then, it is cold rolled from about 0.15 mm to about 0.5 mm, and further annealed at 750 to 1100 ° C. is used as the electrical steel sheet.

  In addition, the surface of the electrical steel sheet on which the insulating film is formed is subjected to any pretreatment such as degreasing treatment with alkali or pickling treatment with hydrochloric acid, sulfuric acid, phosphoric acid, etc. before applying the treatment liquid described later. Alternatively, it may be the surface as it is after the finish annealing without performing the pretreatment.

  Furthermore, in the electrical steel sheet used in the present embodiment, the surface roughness (Ra) is 1.0 μm or less, more preferably 0.1 μm or more and 0.5 μm or less. If Ra is less than 0.1 μm, the cost tends to be high in the cold rolling process, and if it exceeds 1.0 μm, the thermal conductivity tends to deteriorate.

  Next, the metal phosphate used in the present embodiment is a solid content when an aqueous solution mainly composed of phosphoric acid and metal ions is dried, and is used as a binder. Although it does not specifically limit as a kind of acid, Orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, etc. are good.

  Moreover, as a kind of metal ion, light metals, such as Li, Al, Mg, Ca, Sr, and Ti, are favorable, and especially Al and Ca are favorable. When preparing the phosphoric acid metal salt solution, for example, it is preferable to prepare by mixing orthophosphoric acid with metal ion oxide, carbonate and hydroxide.

  The metal phosphate salts may be used alone or in combination of two or more. Moreover, only a phosphoric acid metal salt may be used as a binder, and additives, such as phosphonic acid and boric acid, may be added.

  The colloidal silica used in the present embodiment has an average particle size of 5 to 40 nm and an Na content of 0.5 mass% or less, and more preferably an Na content of 0.01 to 0.3 mass%.

  The average particle size of the colloidal silica and organic resin emulsion used in the present application is the number average particle size. In the case of colloidal silica, it is measured by the nitrogen adsorption method. Measured by laser diffraction method.

  These metal phosphates, colloidal silica, and acrylic resins, epoxy resins, polyester resins and urethane resins having an average particle size of 0.05 to 0.50 μm, or a mixture or copolymer of two or more types are insulated. It is used as a binder for coatings. The thickness of the binder is preferably about 0.5 to 8.0 [mu] m, more preferably 1.0 to 5.0 [mu] m.

  It is also possible to add a binder component other than a mixture of a metal phosphate or colloidal silica and an acrylic resin, epoxy resin, polyester resin or urethane resin. For example, carbonates, hydroxides, oxides, inorganic compounds such as titanates and tungstates, or organic low-molecular compounds such as polyols, cellosolves, carboxylic acids, ethers and esters are added as binder components. May be.

  As the acrylic resin, epoxy resin, polyester resin, and urethane resin used in the present embodiment, each commercially available resin emulsion may be used. Particularly suitable for acrylic resins are methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, n-nonyl. Acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, hydroxyl group as acrylate, n-decyl acrylate, n-dodecyl acrylate, etc. As monomers having 2-hydroxyethyl (meth) acrylate, 2-hydroxylpropyl (meth) acrylate, 3-hydroxylbutyl (meth) acrylate, 2-hydroxylethyl (meth) allyl ether, etc. Those engaged is preferred.

  In the case of an epoxy resin, for example, an amine-modified epoxy resin reacted with a carboxylic acid anhydride, specifically, bisphenol A-diglycidyl ether, caprolactone ring-opening adduct of bisphenol A-diglycidyl ether, bisphenol F-diglycidyl ether, bisphenol S-diglycidyl ether, novolak glycidyl ether, dimer acid glycidyl ether, etc., and the modifying amines include isopropanolamine, monopropanolamine, monobutanolamine, monoethanolamine, diethylenetriamine, ethylenediamine, Butalamine, propylamine, isophoronediamine, tetrahydrofurfurylamine, xylenediamine, hexylamine, nonylamine, triethylenetetramine , Tetramethylenepentamine, diaminodiphenylsulfone, etc., and those obtained by reacting succinic anhydride, itaconic anhydride, maleic anhydride, citraconic anhydride, phthalic anhydride, trimellitic anhydride, etc. as carboxylic anhydrides are suitable. is there.

  Examples of polyester resins include dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, Citraconic acid and the like, and glycols such as ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyldiol 1,6-hexanediol, What reacted with ethylene glycol, dipropylene glycol, polyethylene glycol, etc. is suitable. Further, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, methacrylic anhydride, etc. may be graft polymerized with these polyester resins.

  The urethane resin is obtained by polymerization from a polyvalent isocyanate and a polyhydric alcohol by a conventionally known method, and preferably has a carboxyl group or the like as a polar group for water dispersion. Specifically, examples of the polyvalent isocyanate include ethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, polymethylene polyphenylene polyisocyanate, 1,5-naphthylene diisocyanate, and the like. Examples of the alcohol include polyester polyol, polyether polyol, polyacetal polyol, and polysiloxane polyol. Furthermore, low molecular polyols such as ethylene glycol, propylene glycol, and pentaerythritol may be mixed and polymerized.

  Each organic resin may be an emulsion or a water-soluble resin. In the case of an organic resin emulsion, one or a mixture of two or more of the above organic resins may be used. Moreover, as an average particle diameter of the said organic resin emulsion, the range of 0.05-0.50 micrometer is suitable. If the average particle size is 0.05 μm or less, it tends to agglomerate in the treatment liquid and the uniformity of the insulating coating may be reduced. If the average particle size exceeds 0.50 μm, the stability of the solution may be reduced. is there. The average particle diameter of the organic resin emulsion is more preferably in the range of 0.1 to 0.3 μm.

  The mixing ratio of metal phosphate and acrylic resin, epoxy resin, polyester resin, and urethane resin is 1-50 parts by mass of the total of acrylic resin, epoxy resin, polyester resin, and urethane resin with respect to 100 parts by mass of metal phosphate. Is appropriate. If the total mixing ratio of the acrylic resin, epoxy resin, polyester resin, and urethane resin is less than 1 part by mass, the resin concentration is too thin and aggregation tends to occur, resulting in poor liquid stability. This is because it may be inferior.

  Moreover, the total mixing ratio of colloidal silica and acrylic resin, epoxy resin, polyester resin, and urethane resin is 40 to 400 mass of the total of acrylic resin, epoxy resin, polyester resin, and urethane resin with respect to 100 parts by mass of colloidal silica. The range of the part is appropriate. If the total mixing ratio of the acrylic resin, epoxy resin, polyester resin, and urethane resin is less than 40 parts by mass, the film-forming property may be poor and the insulating coating may powder, and if it exceeds 400 parts by mass, the heat resistance may be inferior. Because there is.

  Next, the fatty acid or fatty acid metal salt used in the present embodiment has a carbon number in the range of 8 to 20. The fatty acid or fatty acid metal salt according to this embodiment is a linear carboxylic acid or a metal salt compound of a linear carboxylic acid. Specifically, the fatty acid is capric acid, lauric acid, myristic acid, stearic acid, lauroleic acid, myristoleic acid, oleic acid, linoleic acid, linolenic acid, gadoleic acid, etc. Specific examples are sodium salt, magnesium salt, calcium salt, potassium salt and the like.

  These fatty acids or fatty acid metal salts may be used alone or in combination of two or more.

  The reason why the number of carbon atoms of the fatty acid or fatty acid metal salt is 8 to 20 is that when the number of carbon atoms is less than 8, the efficiency remaining in the insulating coating is poor due to evaporation or sublimation during baking, and sufficient workability improvement effect cannot be obtained. If it exceeds 20, a large amount of emulsifier is required for emulsification, and the corrosion resistance of the insulating coating may be lowered. The number of carbon atoms of the fatty acid or fatty acid metal salt is more preferably in the range of 10 to 18, and oleic acid and myristic acid are particularly suitable.

  In this embodiment, various surfactants can be used to improve the liquid stability. As the surfactant, it is preferable to use a nonionic surfactant and a cationic surfactant in combination. As the nonionic surfactant, those having an HLB value (hydrophilic / lipophilic ratio) of 8 or more are preferable. Specifically, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, and the like. As the cationic emulsifier, amine compounds such as monoamine compounds, polyamine compounds, and alcoholic amines are preferable. Specifically, stearylamine, N-aminopropylbehenylamine, N-myristylpropylenetetramine, triethanolamine, and the like. is there.

  These surfactants are preferably added in an amount of 2.0 to 15.0 parts by mass with respect to 100 parts by mass of the fatty acid or fatty acid metal salt. If it is less than 2.0 parts by mass, the liquid stability may be deteriorated, and if it exceeds 15.0 parts by mass, the corrosion resistance is lowered. The ratio of the nonionic surfactant to the cationic surfactant is preferably 95: 5 to 30:70 in terms of mass ratio. If the ratio of the cationic surfactant is less than 5, the emulsifying ability is weak and the dispersion of the fatty acid or the fatty acid metal salt may be inferior. If it exceeds 70, the stability of the organic resin is affected, and the liquid stability is also inferior. This is because there is a possibility.

  Further, when the HLB value of the nonionic surfactant is less than 8, the liquid stability is inferior. The HLB value of the nonionic surfactant is more preferably in the range of 12 to 15. The HLB value is a value calculated by the Griffin method.

  Next, the compounding ratio of the phosphoric acid metal salt, the mixture of acrylic resin, epoxy resin, polyester resin, urethane resin, and fatty acid or fatty acid metal salt is 0.3-5. 0 parts by mass. If the blending ratio of the fatty acid or fatty acid metal salt is less than 0.3 parts by mass, the processability improvement effect may be inferior, and if it exceeds 5 parts by mass, the processing solution may become unstable and the coating workability may be reduced. It is.

  The mixture ratio of colloidal silica, acrylic resin, epoxy resin, polyester resin, urethane resin, and fatty acid or fatty acid metal salt is 0.3 to 5 of fatty acid or fatty acid metal salt with respect to 100 parts by mass of the solid content of the binder. Mass parts. This is because if the blending ratio of the fatty acid or the fatty acid metal salt is less than 0.3 parts by mass, the effect of improving the workability is inferior, and if it exceeds 5 parts by mass, the corrosion resistance may be deteriorated.

  In the present embodiment, when the treatment liquid is applied to the surface of the magnetic steel sheet, the application method is not particularly limited, and a roll coater method may be used, or an application method such as a spray method or a dip method may be used.

  Also, the heating method for drying and baking the treatment liquid can be a normal radiant furnace or hot air furnace, and heating using electricity such as an induction heating method may be used.

  As drying conditions, for example, a baking time of 5 to 30 seconds is appropriate in the range of 150 to 400 ° C. Further, among the drying conditions, the ultimate plate temperature is more preferably in the range of 260 to 380 ° C. in the case of a metal phosphate, and in the range of 170 to 250 ° C. in the case of colloidal silica.

  Furthermore, you may add liquid stabilizers, such as a metal chelate, with respect to the above-mentioned process liquid. In addition, brighteners, preservatives, antioxidants and the like may be added.

  In the insulating coating composed of the fatty acid or fatty acid metal salt and a binder, a lubricating region is formed in the insulating coating by the fatty acid or fatty acid metal salt. These lubrication areas maintain the lubricating film by serving to compensate for the lack of lubricating oil when the insulating coating is destroyed as the steel sheet is deformed during the punching process of the electrical steel sheet, and therefore the processing accuracy is improved. Estimated to improve.

  Non-directionality with a plate thickness of 0.35 mm containing Si: 3.15%, Al: 0.6%, Mn: 0.03%, and a surface roughness Ra (centerline average roughness) of 0.38 μm. The treatment liquid shown in Table 1 below was applied and baked on the surface of the electrical steel sheet at the drying temperature shown in the table.

As phosphoric acid metal salt, orthophosphoric acid and each metal hydroxide, oxide, carbonate such as Al (OH) ₃ , Mg (OH) ₂ are mixed and stirred to prepare each phosphorous metal salt treatment solution, A 40 mass% aqueous solution was prepared.

  Colloidal silica having a commercially available average particle size of 15 nm and a surface modified with aluminum at a concentration of 30 mass% was used.

  Further, for each organic resin, the following 6 types of organic resins were used as 30% emulsion solutions. Further, a suitable amount of a viscosity modifier and an antioxidant were added to prepare a treatment liquid having the composition shown in Table 1. About the acrylic resin 3, the epoxy resin 2, the polyurethane 2, and the polypropylene emulsion, it added suitably in the range of 5% or less from ethyl alcohol, isopropyl alcohol, and butyl cellosolve other than water, and was set as 30% aqueous solution.

(1) Acrylic resin 1 obtained by copolymerizing methyl methacrylate 40 mass%, styrene monomer 25 mass%, 2-hydroxyethyl methacrylate and methyl methacrylate 25 mass% as an acrylic resin.
(2) Acrylic resin 2 obtained by copolymerizing 40 mass% of methyl acrylate, 20 mass% of styrene monomer, 35 mass% of isobutyl acrylate, and 5 mass% of ethylene glycol dimethacrylate.
(3) Acrylic resin 3 obtained by copolymerizing 35 mass% of methyl acrylate, 10 mass% of 2-hydroxypropyl (meth) acrylate, 25 mass% of n-nonyl acrylate, and 30 mass% of maleic anhydride.
(3) Amine-modified epoxy resin 1 obtained by modifying bisphenol A with triethanolamine and then reacting with succinic anhydride
(4) Amine-modified epoxy resin 2 obtained by modifying bisphenol A with triethylenetetramine and then reacting with maleic anhydride
(5) Carboxyl group-containing polyester resin obtained by copolymerizing 40% by mass of dimethyl terephthalate and 40% by mass of neopentyl glycol, and then graft-polymerizing 10% by mass of fumaric acid and 10% by mass of trimellitic anhydride (6) 50 parts by mass of terephthalic acid And 50 parts by mass of isophthalic acid, 40 parts by mass of diethylene glycol, and 35 parts by mass of butanediol are heated, and 100 parts by mass of polyester polyol synthesized by a known method by adding dibutyltin oxide as a catalyst, and tolylene diisocyanate 20 An aqueous polyurethane 1 synthesized from parts by mass.
(7) 100 parts by mass of polyester holding carboxyl groups at both ends, 75 parts by mass of polyethylene glycol holding hydroxyl groups at both ends, 80 parts by mass of dicyclohexylmethane diisocyanate, and 10 parts by mass of 2,2 dimethylolpropionic acid were reacted. Synthetic aqueous polyurethane 2
(8) An ethylene vinyl acetate copolymer emulsion synthesized by a known method.
(9) Polyethylene emulsion synthesized by a known method (10) Polypropylene emulsion obtained by graft-modifying polypropylene having a weight average molecular weight of 5000 with maleic anhydride

  The average particle sizes of the acrylic resins 1, 2, and 3 were 0.27 μm, 0.45 μm, and 0.82 μm, respectively. Moreover, the average particle diameters of the epoxy resins 1 and 2 were 0.38 μm and 0.92 μm, respectively. The average particle size of the polyester resin is 0.13 μm, the average particle size of the aqueous polyurethane 1 is 0.17 μm, the average particle size of the aqueous polyurethane 2 is 0.02 μm, and the ethylene vinyl acetate copolymer emulsion has an average particle size of The average particle size was 0.7 μm, the polyethylene emulsion had an average particle size of 0.45 μm, and the polypropylene emulsion had an average particle size of 3.0 μm. In addition, the resin mass part in Table 1 is solid content conversion.

  Predetermined amounts of fatty acids and fatty acid metal salts shown in Table 2 were added to these binder treatment liquids.

  A roll coater method was used for applying the treatment liquid, and the roll reduction amount and the like were adjusted so that the binder film thickness was about 1.5 μm. Drying was performed using a radiation furnace, and the furnace temperature setting was adjusted so that the predetermined heating conditions described in Table 2 were obtained. Although the ultimate plate temperature and the baking time differ depending on the sample, the baking time was adjusted to be in the range of 2 to 40 seconds in the range of 150 to 400 ° C. Table 3 shows the evaluation measurement results of the obtained samples.

  The average particle size is determined by diluting the organic resin emulsion with distilled water, then dispersing it in distilled water with an ultrasonic cleaner for about 1 minute, and then using a commercially available laser diffraction method according to the JIS method (JIS Z8826). The number average particle size was measured with a measuring device.

Below, the evaluation method of the manufactured sample is demonstrated in detail.
For measuring the punching workability of the insulating coating, the magnetic steel sheet on which the insulating coating was formed was punched to 75 mmφ, and the inner diameter and outer diameter of the collected circular sample and punched blank were measured with a three-dimensional measuring machine. The punching die clearance was set to 7%, the die inner diameter was set to 75.035 mm and the punch outer diameter was set to 74.970 mm by 2t pressurization. The three-dimensional measuring machine was measured with a probe diameter of 3 mm, a measurement pitch of 0.1 mm, and a probe speed of 2 mm / s. The punching variation was confirmed 10 times each.

  Deviations in the variation of the measured diameter values in the direction perpendicular to the steel plate rolling direction of the circular sample are 0.006 or less, ◯ 0.01 or less, ◯, 0.015 or less Δ, and 0.015 or more x. did.

Insulation is based on the interlayer resistance measured according to the JIS method (JIS C2550), less than 5 Ω · cm ² / sheet x 5-10 Ω · cm ² / sheet Δ, 10-50 Ω · cm ² / sheet ○, and 50 Ω · cm ² / sheet or more as ◎.

  Adhesion is achieved by winding a steel plate sample after strain relief annealing (annealing temperature 750 ° C. × 2 hours in a nitrogen atmosphere) with a sticking tape attached to a metal rod having a diameter of 10 mm, 20 mm, and 30 mm, and then pulling the adhesive tape. The adhesion was evaluated from the peeled and peeled traces. Those that did not peel off even when bent at 10 mmφ were defined as 10 mmφOK, those that did not peel off at 20 mmφ were 20 mmφOK, those that did not peel off at 30 mmφ were defined as 30 mmφOK, and those that did not peel off were OUT.

  Corrosion resistance was determined according to a JIS salt spray test (JIS Z2371), and a 10-point evaluation was performed on samples after 7 hours. The evaluation criteria are as follows.

10: No rust generation 9: Very little rust generation (area ratio 0.1% or less)
8: Area ratio where rust occurred = 0.1% over 0.25% or less 7: Area ratio where rust occurred = 0.25% exceeding 0.50% or less 6: Area ratio where rust occurred = 0.50 % Excess 1% or less 5: Area ratio where rust occurred = 1% excess 2.5% or less 4: Area ratio where rust occurred = 2.5% exceeding 5% or less 3: Area ratio where rust occurred = 5% Excess 10% or less 2: Rust area ratio = 10% excess 25% or less 1: Rust area ratio = 25% excess 50% or less

  Appearance is glossy and smooth and uniform is 5; hereinafter, gloss is 4 but slightly inferior in uniformity, 3 is slightly glossy and smooth but inferior in uniformity, and gloss is 3 The number 2 was slightly inferior in smoothness and inferior in uniformity, and 1 was inferior in gloss, uniformity and smoothness.

  The heat resistance is the state of peeling of the insulating coating after strain relief annealing (annealing temperature 750 ° C. × 2 hours in a nitrogen atmosphere), and rubbing 2 mm × 30 mm gauze with a load of 100 gf (about 0.98 N) on the steel plate surface. evaluated. What was not peeled was 5, 4 was peeled slightly, 3 was clearly peeled, 2 was severely peeled, and 1 was peeled without rubbing with gauze.

Table 3 revealed the effects of the present invention.
According to Table 3, it was found that the sample corresponding to the example of the present invention had good dimensional accuracy at the time of punching, little variation, and excellent punching workability. Moreover, it turned out that the sample applicable to the Example of this invention is excellent in insulating property, adhesiveness, corrosion resistance, external appearance, and heat resistance in addition to punching workability. In addition, many of the samples corresponding to the comparative examples have poor dimensional accuracy at the time of punching and large variations, and are excellent in all of insulation, adhesion, corrosion resistance, appearance, and heat resistance. Nothing existed.

  As described above, in the electromagnetic steel sheet according to the embodiment of the present invention, in the production of the laminated iron core, the lamination precision of the electromagnetic steel sheet is improved by being excellent in dimensional accuracy at the time of punching, and the gap between the stator and the rotor is narrowed. It is possible.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to this example. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

Claims (4)

  A mixture of one or more of acrylic resin, epoxy resin, polyester resin and urethane resin having 100 parts by mass of metal phosphate as the main component and an average particle size of 0.05 to 0.50 μm on the surface of the electrical steel sheet Alternatively, the fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is 0.3 to 5.0 parts by mass with respect to 100 parts by mass of the solid content of the binder with respect to the binder composed of 1 to 50 parts by mass of the copolymer. A magnetic steel sheet comprising an insulating coating mixed and dispersed in part.   On the surface of the electrical steel sheet, 100 parts by mass of colloidal silica as a main component and one or a mixture of two or more of acrylic resin, epoxy resin, polyester resin and urethane resin having an average particle size of 0.05 to 0.50 μm are used. With respect to the binder composed of 40 to 400 parts by mass of the polymer, 0.3 to 5.0 parts by mass of a fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is mixed with 100 parts by mass of the solid content of the binder. And an insulating steel sheet having a dispersed insulating coating.   One type or a mixture or copolymer of acrylic resin, epoxy resin, polyester resin and urethane resin having an average particle size of 0.05 to 0.50 μm with respect to 100 parts by mass of metal phosphate as a main component After the emulsion is mixed with 1 to 50 parts by mass of resin solid content, the fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is converted to resin solid content with respect to 100 parts by mass of the solid content of the mixture. A method for producing an electrical steel sheet, comprising applying a treatment liquid mixed with ˜5.0 parts by mass to the surface of the electrical steel sheet and baking and drying at an ultimate temperature of 150 to 400 ° C. for 5 to 30 seconds. Resin emulsion of one or a mixture or copolymer of acrylic resin, epoxy resin polyester resin and urethane resin having an average particle size of 0.05 to 0.50 μm with respect to 100 parts by mass of colloidal silica as a main component After 40 to 400 parts by mass of the solid content is mixed, the fatty acid or fatty acid metal salt having 8 to 20 carbon atoms is 0.3% with respect to 100 parts by mass of the solid content of the binder with respect to 100 parts by mass of the solid content of the mixture. A method for producing an electrical steel sheet, comprising applying a treatment liquid mixed with ˜5.0 parts by mass to the surface of the electrical steel sheet and baking and drying at an ultimate temperature of 150 to 400 ° C. for 5 to 30 seconds.