JPH07336969A - Electromagnet steel plate bonded core and manufacturing method - Google Patents

Abstract

PURPOSE:To provide an electromagnet steel plate with good antiblocking and anticorrosion characteristics, by adding a given quantity of cross linkage agent to urethane resin having urethane bonding of a given ratio, and forming a strong film of urethane in a drying step. CONSTITUTION:A non-oriented electromagnet steel plate 0.2mm thick is coated with a coating 4mum thick after drying in a roll coater method and dried for 40sec in a gas heating furnace at 320 deg.C. The coating is made of urethane resin with 3 to 45wt% urethane bonding (-NHCOO-), and a cross linkage agent of 1 to 60 is added to the urethane resin of 100 on a weight basis. After the electromagnet steel plate coated with an adhesive insulating film is punched into rectangular pieces of 20X110mm, 100 pieces of steel plates are laminated and bonded by heat under pressure of 15kg/cm<2> in an induction heating furnace at a temperature up to 240 deg.C. Then, the steel plate has good adhesive strength that is not reduced even at rising temperatures while the steel core is used, and at the same time the steel plate has good antiblocking and anticorrosion characteristics.

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 for iron cores used in electric equipment and the like and a method for producing the same, and more specifically, to form an adhesive type insulation film for producing an adhesive iron core on the surface of an electromagnetic steel sheet material. The present invention relates to an electromagnetic steel sheet for an adhesive core and a method for manufacturing the same. Such an electromagnetic steel sheet for an adhesive core is cut or punched, laminated or wound, and then pressed (fixed to the core) under heating to form an adhesive core.

[0002]

2. Description of the Related Art Generally, a magnetic steel sheet for an iron core used in electric equipment or the like has an insulating film formed on its surface in order to reduce eddy current loss (iron loss). When manufacturing the iron core,
First, a steel sheet on which an insulating film is formed is cut or punched into a predetermined shape, laminated or wound, and then fixed as a laminated core or a wound core.

As a method of fixing to such a laminated iron core or a wound iron core, conventionally, a caulking method, a welding method and an adhesion method have been adopted. However, the caulking method and the welding method have a drawback that the insulation film is destroyed and the iron plate is electrically short-circuited, which causes an increase in eddy current, and mechanical strain or thermal strain deteriorates magnetic properties and mechanical properties. Have. Further, in the bonding method, the work of applying an adhesive to each of the steel plates after cutting or punching, drying and fixing it requires a great deal of labor, and there are various problems in working efficiency and processing accuracy of the iron core.

Therefore, in recent years, there has been proposed a method of manufacturing an adhesive core by forming an adhesive type insulating film that exhibits an adhesive action by heating on the surface of a steel sheet in advance and omitting the above-mentioned adhesive application step. That is, a method of producing an adhesive core fixed by pressing or heating under heat to laminate an electromagnetic steel sheet having an adhesive type insulating film formed thereon by cutting or punching it into a predetermined shape in accordance with a conventional method, is disclosed in Japanese Patent Publication No. 52-8998. , JP-A-2
-38042 and Japanese Patent Application Laid-Open No. 2-208034, and an electromagnetic steel sheet for an adhesive iron core used in this method is disclosed in Japanese Patent Application Laid-Open No. 48-100602.

The adhesive type insulation film disclosed in Japanese Patent Laid-Open No. 48-100602 has a thermoplastic epoxy resin as a main component for exhibiting adhesiveness under heating, and further has a temperature of 140 ° C. or higher during use as an iron core. In order to secure heat resistance that does not lose adhesive strength even when the temperature rises, that is, adhesive strength under temperature rise, alkyd resin as thermosetting resin,
One or two of phenol resin, epoxy resin, melamine resin, polyurethane resin, silicon resin, polyimide resin
The seeds or more are added.

[0006] However, in the magnetic steel sheet for an adhesive iron core having such a film formed, if a large amount of thermosetting resin is added, poor drying occurs and blocking resistance (blocking: exhibiting tackiness and wound into a coil). After that, it becomes fixed and the film cannot be rewound). If the drying conditions are strengthened in order to prevent this, the curing of the resin will proceed and the adhesive strength will decrease, so that the blocking resistance must be decreased in order to ensure the desired adhesive strength. On the other hand, even if the mixing ratio of the thermoplastic resin and the thermosetting resin is adjusted, the hardening state of the thermosetting resin changes with a slight change in the drying conditions. Then, there is no choice but to form a film in a state of poor drying, and in addition to a decrease in blocking resistance, there is a problem that sufficient corrosion resistance cannot be obtained such as rust on the end face of the coil during long-term storage in the coil state.

Further, Japanese Patent Publication No. 52-8998, Japanese Patent Laid-Open No. Hei 2
In the techniques disclosed in Japanese Patent Application Laid-Open No. 38042/1990 and Japanese Patent Application Laid-Open No. 2-208034, a method of forming an adhesive type coating film by an aqueous coating composition containing a thermoplastic resin emulsion and a thermosetting resin emulsion as main components is used. Is proposed. Adhesion accompanying mixing of thermoplastic resin and thermosetting resin in order to prevent explosion and fire during coating work in the conventional method of coating and drying solvent-based paint, or to solve hygiene problems for workers Considering the balance between strength and blocking resistance, and further considering the improvement of properties such as weldability, it is intended to limit the physical properties and composition such as the glass transition point of the thermoplastic resin and thermosetting resin contained. is there.

However, even in these techniques, the above-mentioned balance between the adhesive strength and the blocking resistance is insufficient, and the following drawbacks are caused by using the water-based paint in which the resin is emulsified in these techniques. Have.

That is, a large amount of an emulsifier (surfactant) is contained in the water-based paint in order to emulsify the resin. Therefore, during the coating operation, foaming causes a coating defect or fine bubbles are contained in the coating film. There is a problem that the adhesion and corrosion resistance of the coating deteriorate. In addition, since the emulsifier component is contained in the film, this lowers the adhesive strength, and for the above reason, when the film is formed in a state of poor drying, the hydrophilic group contained in the emulsifier component exhibits a hygroscopic effect and the tackiness of the film. However, the deterioration of blocking resistance and corrosion resistance is a serious problem.

As described above, each of the adhesive type insulating coatings in the above technique is formed by mixing a specific thermoplastic resin and a specific thermosetting resin, and exhibits different properties under heating. It essentially has the above-mentioned problems caused by mixing a thermoplastic resin and a thermosetting resin.

Furthermore, as a point to be improved in the above-mentioned prior art, there is a problem that the scratch resistance is inferior. That is,
The above-mentioned conventional technology is a completely organic film, and because the film strength is poor, scratches are likely to occur in the film during iron core processing, and the adhesive strength and interlayer insulating property are reduced by the scratches, and the film powder is scraped off. However, there is a problem that they are reattached to form a defective portion.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide good adhesive properties in which the adhesive strength does not decrease even when the temperature rises during use of the iron core. An object of the present invention is to provide an electromagnetic steel sheet for an adhesive core, which has an adhesive type insulating film having excellent blocking resistance and corrosion resistance, and a method for manufacturing the same. A second object of the present invention is to provide an electromagnetic steel sheet for an adhesive core, which has an adhesive type insulation film having further excellent scratch resistance, and a method for producing the same.

[0013]

Means and Actions for Solving the Problems The purpose of adding a thermosetting resin to the thermoplastic resin in the above-mentioned prior art is to suppress the softening flow of the thermoplastic resin in the film, which occurs when the temperature of the iron core rises. In order to suppress the decrease in adhesive strength due to the softening flow.

That is, since the addition of the thermosetting resin is basically in the direction of suppressing the adhesive action of the thermoplastic resin, even if the rate of decrease in the adhesive strength due to the temperature rise is improved as described above, it does not change at room temperature. Inevitably, the problem of reduced adhesive strength at room temperature is inevitable. Therefore, in order to secure the adhesive strength, it is unavoidable to form a film within the range where the thermosetting resin is not excessively cured during coating and drying, which makes it difficult to set the drying conditions and balance the coating composition and cause blocking due to poor drying. This has led to a decrease in corrosion resistance.

In consideration of the fact that the temperature rise during use of the iron core is in the range of normal temperature to 200 ° C. and that the bonding work of the iron core is carried out at a heating temperature of 200 ° C. or higher, the present inventors consider Due to the nature of the urethane bond contained in the molecule of the resin, the urethane bond is thermally dissociated to about 200
It was noted that it showed almost no fluidity up to 0 ° C, and exhibited a large fluidity and tackiness necessary for adhesion in the temperature range of over 200 ° C for heat-bonding. As a result of repeated studies to optimize this, the present invention has been completed.

That is, according to the present invention, firstly, the electromagnetic steel sheet material (A) and the urethane bond (-NHCOO-) are added in an amount of 3 to 45.
To provide an electromagnetic steel sheet for an adhesive core, comprising an adhesive type insulating coating layer (B) formed by adding a crosslinking agent in an amount of 1 to 60 parts by weight with respect to 100 parts by weight of a urethane resin contained by weight%, The adhesive strength of the core does not almost decrease even when the temperature rises during use of the iron core. It exhibits blocking resistance and corrosion resistance.

Second, with respect to 100 parts by weight of the electromagnetic steel sheet material (A) and 100 parts by weight of a urethane resin containing a urethane bond (-NHCOO-) in an amount of 3 to 45% by weight, a crosslinking agent in an amount of 1 to 6 is used.
Provided is an electromagnetic steel sheet for an adhesive core, which comprises 0 part by weight and 5 to 30 parts by weight of oxide fine particles having an average particle diameter of 100 nm or less, and an adhesive type insulating coating layer (B). A urethane resin whose adhesive strength does not almost decrease even when the temperature rises, and a film composed of a cross-linking agent and oxide fine particles are formed by sufficiently and thoroughly drying with a proper blending of the cross-linking agent. It exhibits excellent blocking resistance, corrosion resistance, and scratch resistance.

In particular, the use of a soap-free water-based urethane resin (urethane resin hydrated without using an emulsifier) dramatically improves the adhesion and corrosion resistance of the film. That is, a urethane bond (-NHCOO
-) Is 3 to 45% by weight of a soap-free water-based urethane resin 100 parts by weight, a water-borne coating obtained by adding 1 to 60 parts by weight of a cross-linking agent, or in addition, an average particle diameter of 100 nm or less When a water-based paint prepared by adding 5 to 30 parts by weight of oxide fine particles is applied to the surface of a steel sheet, it does not use an emulsifier, so that it is much less likely to foam than a conventional emulsion resin. It is difficult for coating defects due to foaming and bubbles to be contained in the film during work. Therefore, by drying such a water-based paint to form an adhesive type insulating film, the adhesion and corrosion resistance of the film are significantly improved.

In the first aspect of the present invention, a urethane bond (-NHCOO-) is used as an adhesive type insulating film layer.
The amount of the cross-linking agent added is 1 to 60 parts by weight with respect to 100 parts by weight of the urethane resin containing 45% by weight.
This is formed on at least one surface of the electromagnetic steel sheet material.

The urethane resin used for the adhesive type insulating coating layer is not particularly limited as long as it contains 3 to 45% by weight of urethane bond in its molecule, but it contains polyisocyanate and hydrophilic group. A soap-free water-based urethane resin composed of a compound and an active hydrogen-containing compound is desirable.

Examples of the polyisocyanate include 2,4-tolylene diisocyanate, phenylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate and 4,4.
-Dicyclohexylmethane diisocyanate, isophorone diisocyanate and the like can be mentioned.

Examples of the hydrophilic group-containing compound include 2-oxyethanesulfonic acid, sulfosuccinic acid, sulfanilic acid, sulfonic acid compounds such as 2,4-diaminotoluenesulfonic acid, 2,2-dimethylolpropionic acid, and the like.
Examples thereof include carboxylic acid-containing compounds such as dioxymaleic acid and 3,4 diaminobenzoic acid, and polyoxyethylene glycol or polyoxyethylene-polyoxypropylene copolymer glycol having at least one active hydrogen in the polymer. .

Examples of active hydrogen compounds include high molecular weight compounds such as polyester polyols and polyether polyols, and if necessary, glycerin, polyoxy compounds typified by trimethylolpropane, diamine compounds typified by ethylenediamine and piperazine. The low molecular weight compound is used in combination with the above high molecular weight compound.

In the present invention, when the urethane bond of the urethane resin is less than 3% by weight, the flow of the film during heat bonding is insufficient and the adhesive strength is lowered. On the other hand, if the content exceeds 45% by weight, on the contrary, the flow of the coating during heat bonding becomes excessive, and the fluidized coating is extruded to the end face of the iron core due to the pressurization to contaminate the end face or change the stacking height of the iron core. Cause the evil of. Therefore, the urethane bond of 3 to 45% by weight is in a proper range for securing the adhesive strength.

The cross-linking agent added to the urethane resin is to cure the urethane resin by a cross-linking reaction with the terminal functional group of the urethane resin to cure it as a film.
Although it is not particularly limited as long as it has such an action, it is desirable to use one or two or more of epoxy resin, urea resin, melamine resin, and phenol resin.
Examples of the epoxy resin include an aliphatic polyol-based epoxy resin, a bisphenol A-based epoxy resin, a bisphenol F-based epoxy resin, and a novolac-based epoxy resin.

The cross-linking agent is added in an amount of 1 to 60 parts by weight based on 100 parts by weight of the urethane resin. If this amount is less than 1 part by weight, sufficient film hardening will not proceed during coating and drying, and the adhesive strength will decrease, and at the same time, film peeling (cohesive failure) will occur during iron core processing, and the film adhesion will decrease.
On the other hand, when the content is more than 60 parts by weight, the excess curing agent that does not contribute to the crosslinking reaction deteriorates the adhesive strength, the blocking resistance and the corrosion resistance. From the viewpoint of cross-linking with the urethane resin in a necessary and sufficient manner and stably exhibiting the effect, the addition amount of the cross-linking agent is preferably 5 to 40 parts by weight.

In forming such an adhesive type insulation film layer, the coating composition is based on 100 parts by weight (as solid content) of the soap-free water-based urethane resin containing 3 to 45% by weight of the urethane bond. , The cross-linking agent,
It is preferable to use an aqueous coating obtained by adding 1 to 60 parts by weight (as a solid content) of one or more of epoxy resin, urea resin, melamine resin and phenol resin.
As described above, the soap-free water-based urethane resin, which is the main component, does not contain an emulsifier, so it is much less likely to foam compared to the emulsion resin in the prior art, and coating defects due to foaming in the coating work on magnetic steel sheet materials. And the adhesion of the film due to the inclusion of air bubbles in the film,
The reduction in corrosion resistance is greatly improved.

The epoxy resin, urea resin, melamine resin, phenol resin and the like added as a crosslinking agent are not particularly limited, and those containing an emulsifier are also included in the scope of the present invention. It is also possible to add a small amount of a surfactant in order to improve the coating wettability on the steel sheet (prevent cissing). However, from the viewpoint of foamability, it is desirable that the emulsifier or the surfactant is not contained or the content is as small as possible.

In any case, the problem due to the foaming property is remarkably improved and the emulsifier component of the emulsifier component contained in the film is remarkably improved as compared with the water-based coating composition containing a large amount of the emulsifier according to the prior art as a main component. Since the amount is significantly small, it has a great effect on improving the corrosion resistance. In addition, it is also effective in preventing a decrease in adhesive strength, blocking resistance or insulation due to moisture absorption when left for a long time.

A water-based paint having such a composition is applied to the surface of a magnetic steel sheet material and dried in a heating oven to form an adhesive type insulation film layer. The coating method is roll coater method, roll drawing method,
Any method such as a gas squeezing method or an electrostatic coating method may be used as long as it is applied uniformly to a predetermined film thickness. Also, drying after application is
The plate temperature is usually adjusted within a range of 150 to 350 ° C. so that the coating film is completely and strongly dried by a gas heating method, a hearth roll method, an induction heating method, or the like. After drying and heating, the plate temperature is usually cooled to 80 ° C. or lower and wound into a coil.

The thickness of the film is not particularly limited, but 0.3 to 10 μm per side is appropriate. 0.
When the thickness is less than 3 μm, the spreadability of the film flow during heat bonding is lacking and the bonding strength decreases. On the other hand, when the thickness is more than 10 μm, the coating film is apt to cause cohesive peeling during processing of the iron core, which causes problems such as dusting. The thickness of the film is appropriately selected in consideration of the surface roughness of the steel sheet, the required interlayer insulation resistance, and the additional effects such as the magnetic properties and vibration damping properties brought about by the formation of the adhesive type film, but secures a stable adhesive strength. In addition, in order not to inhibit the decrease of the space factor, the range is preferably 0.5 to 5 μm.

In the second aspect of the present invention, a urethane bond (-NHCOO-) 3 is used as the adhesive type insulating film layer.
1 to 60 parts by weight and an average particle size of 100 n with respect to 100 parts by weight of a urethane resin containing 45 to 45% by weight.
What added 5 to 30 weight part of oxide fine particles of m or less is used, and this is formed on at least one surface of the electromagnetic steel sheet material.

In this embodiment, the same urethane resin and crosslinking agent as in the first embodiment can be used. Also, the average particle size of 10 added in addition to the crosslinking agent
The oxide fine particles having a particle size of 0 nm or less improve abrasion resistance, and further improve corrosion resistance and blocking resistance. The material of the oxide fine particles is not particularly limited as long as the above effects can be obtained, but it is preferable to use one or both of silica and alumina.

The average particle diameter of the oxide fine particles is 100 n.
If it exceeds m, the adhesive strength decreases. Further, when the oxide fine particles are less than 5 parts by weight, the above effect cannot be sufficiently exhibited, and when the oxide fine particles are contained in excess of 30 parts by weight, the adhesive strength is lowered. When silica is used as the oxide fine particles, the smaller the particle size is, the greater the above effect is, and the particle size in the range of 4 to 20 nm is suitable.

In this embodiment, in forming the adhesive type insulating coating layer, the coating composition has 100 parts by weight (as solid content) of the soap-free water-based urethane resin containing 3 to 45% by weight of the urethane bond. 1 to 60 of the above-mentioned cross-linking agent, preferably one or more of epoxy resin, urea resin, melamine resin and phenol resin.
An aqueous paint prepared by adding 5 parts by weight (as solid content) and 5 to 30 parts by weight (as solid content) of oxide fine particles having a particle diameter of 100 nm or less, preferably silica and / or alumina is used. As a result, also in this aspect, due to the same action as in the first aspect, the coating defect due to foaming and the decrease in the adhesiveness and corrosion resistance of the coating due to the inclusion of bubbles in the coating are significantly improved. Further, the epoxy resin, urea resin, melamine resin, phenol resin, etc. added as a cross-linking agent are not particularly limited, and may contain an emulsifier as in the first embodiment, and may contain a small amount of surface active agent. It is also possible to add agents. And, like the first aspect, the problem due to the foaming property is significantly improved, and the amount of the emulsifier component contained in the film is significantly small, which brings about a great effect on the improvement of the corrosion resistance. It is also effective in preventing deterioration of adhesive strength, blocking resistance, or insulation due to moisture absorption when left for a period of time.

As the oxide fine particles such as silica and alumina having a particle diameter of 100 nm or less contained in the paint, those produced by a wet method or a dry method are used.
These may be previously dispersed in water and added as a colloidal solution, or may be directly mixed with the coating material in a powder state. In order to improve the dispersion stability in the paint, it is also possible to use those having the surface of the fine particles subjected to a stabilizing treatment.

Also in this aspect, as in the first aspect, the above-mentioned aqueous coating material is applied to the surface of the electromagnetic steel sheet material and dried to form the adhesive type insulating film layer. The method of applying the coating material and the thickness of the adhesive type insulating film layer are the same as in the first aspect.

In any of the embodiments, the electromagnetic steel sheet material for forming the adhesive type insulation film is not particularly limited as long as it is used for the adhesive core, and non-oriented electrical steel sheet and grain-oriented electrical steel sheet are mainly targeted. Becomes Especially 6.5% Si
High Si steel plates such as steel plates and thin electromagnetic steel plates having a plate thickness of 0.2 mm or less have poor adhesion strength of the iron core due to deformation of the joints and magnetic properties are deteriorated by the conventional welding method and caulking method. It is effective to form an adhesive type insulating film in and use it as an adhesive core. It is also possible to form the adhesive insulating film of the present invention on the surface of a non-oriented electrical steel sheet on which a general-purpose inorganic or inorganic-organic insulating coating is formed or a grain-oriented electrical steel sheet on which a tension-added coating is formed. It is not beyond the scope of the invention.

The electromagnetic steel sheet for an adhesive iron core of the present invention thus obtained is usually used as a laminated iron core or a wound iron core after being cut or punched, and then laminated or wound, under heating at a plate temperature of 200 to 350 ° C. 5 to 50 kg / cm ²
It is fixedly molded by applying pressure to form an adhesive core.

[0040]

【Example】

(Example 1) The surface of a non-oriented electrical steel sheet having a plate thickness of 0.2 mm was coated with a coating material having the composition shown in Tables 1 and 2 by a roll coater method so that the film thickness after drying was 4 μm, Heating and drying was performed for 40 seconds in a gas heating furnace in which the furnace temperature was set to 320 ° C. The electromagnetic steel sheet having an adhesive type insulating film thus obtained was punched into a rectangle of 20 × 110 mm, 100 sheets of this were stacked and pressed at a pressure of 15 kg / cm ² to reach an ultimate plate temperature of 240 in an induction heating furnace. A sample having a laminated iron core shape was prepared by heating and adhering so that the temperature became ℃.

The urethane resins in Tables 1 and 2 are as follows. Urethane resin (A); soap-free water-based urethane resin consisting of 2,4-tolylene diisocyanate, 2,2-dimethylolpropionic acid and polyester polyol Urethane resin (B); 4,4-dicyclohexylmethane diisocyanate and 2-oxyethane Soap-free water-based urethane resin composed of sulfonic acid and polyester polyol Urethane resin (C); Soap-free water-based urethane resin composed of 2,4-tolylene diisocyanate, 2,2-dimethylolpropionic acid and polyester polyol Urethane resin (D); Isophorone diisocyanate and 2
-Soap-free water-based urethane resin composed of oxyethanesulfonic acid and polyester polyol Urethane resin (E); Water-based urethane resin emulsion composed of 2,4-tolylene diisocyanate, polyester polyol and nonionic surfactant

[0042]

[Table 1]

[0043]

[Table 2]

In order to grasp the adhesive strength, blocking resistance and corrosion resistance of the electromagnetic steel sheets (inventive examples 1 to 7 and comparative examples 1 to 5) on which the adhesive type insulating coating is formed in this manner, the following various types are shown. The test was conducted.

(1) Adhesive strength at room temperature Two pieces of the rectangular punched steel plates of 20 × 110 mm are piled up so that the overlapping portion becomes 20 × 30 mm, and then 15 k.
It was heated so that the ultimate plate temperature was 240 ° C. under a pressure of g / cm ² to obtain a test sample in which two sheets were adhered. This was pulled in the longitudinal direction by a tensile tester and the maximum load until breaking, that is, the tensile shear load was measured.

(2) Adhesive strength at 120 ° C. The tensile shear load of the test sample obtained by heating and adhering was measured in the state heated at 120 ° C. in the same manner as in the above-mentioned method (1).

(3) Blocking resistance Two pieces of the rectangular punched steel plates of 20 × 110 mm are piled up so that the overlapping portion is 20 × 30 mm, and 30
After the plate was left under a pressure of 0 kg / cm ² at a plate temperature of 80 ° C. for 5 hours, the tensile shear load was measured at room temperature in the same manner as in the above (1).

(4) Corrosion resistance The rectangular punched steel plate of 20 × 110 mm is 100
A laminated core-shaped sample prepared by laminating one sheet at a temperature of 50
After being left for 5 days in a thermo-hygrostat having a humidity of 90% and a humidity of 90%, the laminated steel sheet was forcibly peeled off and the rust-occurring area of the overlapped portion was measured. The test results are shown in Table 3.

[0049]

[Table 3]

As shown in Table 3, the comparative examples are out of the scope of the present invention, and the adhesive strength, blocking resistance, and
And the corrosion resistance was inferior. That is, in Comparative Example 1, the urethane bond was less than 3% by weight and the adhesive strength was poor. In Comparative Example 2, the urethane bond was more than 45% by weight, and the fluid film was extruded on the end face of the iron core due to the pressure applied during heating and adhesion, and the adhesive strength was also lowered. In Comparative Example 3, the crosslinking agent was 1
The content was less than 10% by weight, the coating strength was insufficient after coating and drying, and the coating was prone to cohesive failure, resulting in poor adhesive strength. Also, the corrosion resistance was poor. In Comparative Example 4, the cross-linking agent was more than 60% by weight and the adhesive strength, blocking resistance and corrosion resistance were poor. Comparative Example 5 is a film formed mainly of a thermoplastic resin emulsion and a thermosetting resin emulsion, which are typified by conventional techniques, and the adhesive strength is lowered by a temperature increase of 120 ° C., and the blocking resistance and the corrosion resistance are also reduced. It was very inferior.

In comparison with these, it was confirmed that each of Examples 1 to 7 of the present invention had sufficient adhesive strength and had extremely good blocking resistance and corrosion resistance. (Example 2) The surface of a non-oriented electrical steel sheet having a plate thickness of 0.2 mm was coated with a coating material having a composition shown in Tables 4 to 6 by a roll coater method so that the film thickness after drying was 4 μm, Heating and drying was performed for 40 seconds in a gas heating furnace in which the furnace temperature was set to 320 ° C. The electromagnetic steel sheet having an adhesive type insulating film thus obtained was punched into a rectangle of 20 × 110 mm, 100 sheets of this were stacked and pressed at a pressure of 15 kg / cm ² to reach an ultimate plate temperature of 240 in an induction heating furnace. A sample having a laminated iron core shape was prepared by heating and adhering so that the temperature became ℃. As the urethane resin in Tables 4 to 6, the resins (A) to (E) were used as in Example 1.

[0052]

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6]

Magnetic steel sheets on which the adhesive type insulation film was formed in this manner (invention examples 8 to 14 and comparative examples 6 to 10)
Various tests were carried out in order to understand the adhesive strength, blocking resistance, corrosion resistance, and scratch resistance of the. The same tests as in Example 1 were performed for adhesive strength, blocking resistance, and corrosion resistance. For scratch resistance, a continuous weighted scratch tester was used, and the tip radius was 1. A scratching needle of 0 mmR was pressed and scratched at a constant speed while continuously applying a load, and the starting point load with a flaw at which scratches were visually observed was measured. The test results are shown in Table 7.

[0056]

[Table 7]

As shown in Table 7, the comparative examples are out of the scope of the present invention, and the adhesive strength, blocking resistance, and
Either corrosion resistance or scratch resistance was inferior. That is, in Comparative Example 6, the urethane bond was less than 3% by weight and the adhesive strength was poor. In Comparative Example 7, the urethane bond was more than 45% by weight, and a fluidized film was extruded on the end face of the iron core by the pressure applied during heat bonding, and the adhesive strength was also lowered. Comparative Example 8
The amount of the cross-linking agent was less than 1% by weight, the film strength was insufficient (adhesion was poor) after coating and drying, and the adhesive strength was poor. Also, the corrosion resistance was poor. In Comparative Example 9, the crosslinking agent was 6
The content was more than 0% by weight, and the adhesive strength, blocking resistance, and corrosion resistance were poor. Comparative Example 10 is a film formed mainly of a thermoplastic resin emulsion and a thermosetting resin emulsion, which are typified by conventional techniques, and the adhesive strength is lowered by the temperature increase of 120 ° C., and the blocking resistance and the corrosion resistance are also reduced. It was very inferior.

In comparison with these, Examples 8 to 14 of the present invention are
It was confirmed that all of them have sufficient adhesive strength and have extremely good blocking resistance, corrosion resistance, and scratch resistance.

[0059]

As described above, according to the present invention,
It has good adhesive properties such that the adhesive strength does not decrease even when the temperature rises when the iron core is used, and it has excellent blocking resistance and corrosion resistance, or even excellent scratch resistance.
Provided are an electromagnetic steel sheet for an adhesive core having an adhesive insulating film formed thereon and a method for producing the same.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07C 271/02 9451-4H H01F 1/16 27/24 H02K 1/18 B // C23C 22/00 A 22/02 (72) Inventor Masaaki Yamashita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (6)

[Claims] 1. A magnetic steel sheet material (A) and 100 parts by weight of a urethane resin containing a urethane bond (—NHCOO—) in an amount of 3 to 45% by weight, and a crosslinking agent in an amount of 1 to 60 parts by weight. A magnetic steel sheet for an adhesive core, which comprises an adhesive type insulating film layer (B). 2. A magnetic steel sheet material (A) and 100 parts by weight of a urethane resin containing a urethane bond (—NHCOO—) in an amount of 3 to 45% by weight, a crosslinking agent in an amount of 1 to 60 parts by weight and an average particle diameter of 100 nm. Add the following oxide particles to 5-3
An electromagnetic steel sheet for an adhesive core, comprising an adhesive type insulating film layer (B) formed by adding 0 part by weight. 3. The electromagnetic steel sheet for an adhesive core according to claim 1, wherein the urethane resin is a soap-free water-based system. 4. The adhesive iron core according to claim 1, wherein the cross-linking agent is one kind or a mixture of two or more kinds of epoxy resin, urea resin, melamine resin or phenol resin. Magnetic steel sheet for use. 5. A urethane bond (—NHCOO—) having 3 to
Soap-free water-based urethane resin 1 containing 45% by weight
An adhesive characterized by applying an aqueous coating composition obtained by adding 1 to 60 parts by weight of a cross-linking agent to 00 parts by weight on at least one surface of a magnetic steel sheet material and drying it to form an adhesive type insulating film. Manufacturing method of steel plate for iron core. 6. A urethane bond (—NHCOO—) having 3 to
Soap-free water-based urethane resin 1 containing 45% by weight
With respect to 00 parts by weight, 1 to 60 parts by weight of a cross-linking agent and 5 to 30 parts by weight of oxide fine particles having an average particle diameter of 100 nm or less are applied to at least one surface of an electromagnetic steel sheet material, A method for producing a steel plate for an adhesive core, which comprises drying to form an adhesive insulating film.