WO2006043612A1

WO2006043612A1 - Heat resistant adhesive film and electromagnetic steel sheet with said heat resistant adhesive film, iron core using said electromagnetic steel sheet, and process for manufacturing the same.

Info

Publication number: WO2006043612A1
Application number: PCT/JP2005/019264
Authority: WO
Inventors: Noriko Yamada; Hiroyasu Fujii; Yuji Kubo; Kazutoshi Takeda; Fumiaki Takahashi; Yoshihiro Arita; Yoshifumi Ohata
Original assignee: Nippon Steel Corporation
Priority date: 2004-10-18
Filing date: 2005-10-13
Publication date: 2006-04-27
Also published as: JP5494602B2; TW200618000A; KR20070042198A; KR20080104061A; MY142207A; KR100921015B1; CN101040022A; CN101040022B; TWI328235B; JP4860480B2; JP2012046825A; JPWO2006043612A1; KR100886236B1

Abstract

This invention provides an electromagnetic steel sheet, which, after lamination, can be bonded by pressing and heating, can realize strain relieving annealing, and has a surface covered with a heat resistant adhesive insulating film, an iron core using the electromagnetic steel sheet, and a process for manufacturing the same. The electromagnetic steel sheet is covered with a heat resistant adhesive insulating film comprising a resin, which softens at room temperature or above and 300˚C or below, and a low-melting inorganic component having a softening temperature of 1000˚C or below as measured by a differential thermal analysis method. A strain relieving annealable bonded fixed iron core is provided by stacking this electromagnetic steel sheet and conducting press fixation.

Description

Technical field of heat-resistant adhesive film, electrical steel sheet with heat-resistant adhesive film coated thereon, iron core using the electrical steel sheet, and manufacturing method thereof

In the present invention, after lamination, pressurization and heating (in the present invention, unless otherwise specified, the heat treatment is performed at room temperature or more and 300 or less), and thereafter annealing treatment such as strain relief annealing (this In the invention, unless otherwise specified, it means a heat treatment exceeding 300.)

The present invention relates to a heat-resistant adhesive coating composition that can be produced and a surface-coated electrical steel sheet. Background art

Electrical steel sheets are mainly used as iron cores for motors and transformers. Usually, the surface of an electrical steel sheet is formed with an insulating coating, and after being continuously punched into a predetermined shape, it is laminated and integrated by a method such as welding or fitting of uneven parts called caulking. It is common to form an iron core.

The integrated iron core can be used as it is incorporated in electrical equipment, or it can be used in electrical equipment after annealing at temperatures around 700 ^ to 800. The latter annealing is called strain relief annealing, and it removes or reduces the shear strain introduced into the steel sheet during punching / shearing, thermal strain generated by welding of the end face, and plastic deformation strain of the caulking portion. However, with the aim of enhancing the magnetic properties of the iron core, it is applied to iron cores used in electrical equipment applications that require high electrical efficiency. In the method of integrating magnetic steel sheets laminated by welding or caulking, there are problems that the edge of the iron core is short-circuited and insulation is lowered, and that magnetic properties are deteriorated due to processing strain. As a method of avoiding defects due to welding and caulking, a technology has been proposed in which an insulating coating that exhibits adhesiveness is formed on a magnetic steel sheet in advance by thermocompression bonding, and after stamping or shearing, it is laminated and thermocompression bonded. Yes.

For example, a method for producing a surface-coated electrical steel sheet for bonding, characterized in that a liquid mixture mainly composed of acryl-modified epoxy resin emulsion containing a latent curing agent is applied and incompletely baked (patent no. No. 2613725) and electrical steel sheets with insulating coatings coated with an adhesive resin containing a foaming agent (Japanese Patent Laid-Open No. 2002-260910), and also Japanese Patent Publication No. 55-9815 and Japanese Patent Laid-Open No. 2-208034 The technology of the gazette is proposed. These so-called adhesive coating techniques can alleviate the problems caused by caulking and welding, but since the steel sheet surface is coated only with organic matter, many of them decompose at temperatures above 300, and distortion is eliminated. Adhesive strength cannot be maintained after annealing. For this reason, magnetic steel sheets with adhesive coating can be used for iron cores that are not subjected to strain relief annealing, but cannot be used for iron cores that are subjected to strain relief to reduce iron loss. There was a problem.

On the other hand, it is possible to use a method in which a magnetic steel sheet that has been processed into a predetermined shape by punching or the like is strain-annealed and then fixed with an adhesive, but it is necessary to apply adhesive to each small punched piece. The workability is bad.

JP-B-42-24519, JP-A-58-128715, JP-B-47-47499 disclose so-called inorganic coatings that do not contain a resin component. . Since Japanese Patent Publication No. 42-24519 does not have a bonding function between steel plates, an integrated iron core cannot be obtained unless a fixing method other than bonding such as caulking or welding is performed. JP Japanese Laid-Open Patent Publication Nos. 58-128715 and 47-47499 have the problems that the film is hard because it is an inorganic film composed only of a low-melting-point glass component, and the punching die is adversely affected, and there is a lot of dust generation. It was. Disclosure of the invention

The present invention improves the heat resistance of the adhesive insulating coating of the electrical steel sheet with the adhesive insulating coating, and the heat resistant adhesive insulating coating that can maintain the adhesive state and the insulating property even when strain relief is performed, and the same The present invention provides an electromagnetic steel sheet with a heat-resistant adhesive coating, an iron core using the electromagnetic steel sheet, and a method for manufacturing the same.

In order to solve the above problems, the present invention uses the following means.

(1) A heat-resistant adhesive insulating coating comprising a resin having a softening point temperature of room temperature to 300 ° C and a low melting point inorganic component having a softening point temperature of 1000 or less.

(2) The heat-resistant adhesive insulating coating according to (1), wherein 250 ^ adhesive strength = 10 kg / cm ² or more, and 750, adhesive strength = lkg / cm ² or more.

(3) 30 linear thermal expansion coefficient at 300 from in the 10X 10- ⁷ (in - ¹⁾ or 15 0X 10 ^"7 (in - ¹⁾ heat adhesion according to (1) the less is Insulating coating.

(4) The heat-resistant adhesive insulating coating according to (1), wherein the low-melting-point inorganic component is a low-melting-point glass frit, water glass, or a mixture of them with colloidal silica.

(5) The heat-resistant adhesive insulating coating according to (4), wherein the low melting point inorganic component has an average particle size of 20 or less.

(6) The heat-resistant adhesive insulating film according to (4), wherein the mixing ratio of the resin to the low-melting-point inorganic component is 20% or more and 500% or less by mass fraction. (7) The heat-resistant adhesive insulation according to (4), characterized in that the low-melting point inorganic component is S i 0 ₂ -B ₂ 0 ₃ -R ₂ 0 series low-melting point glass (R is Al force re-metal) Coating.

(8) The heat-resistant adhesive insulating coating according to (4), wherein the water glass is sodium silicate.

(9) Resin that is baked incompletely with a mixed liquid mainly composed of epoxy resin, acrylic resin, phenolic resin, and acrylic modified epoxy resin emulsion containing a latent curing agent, or The heat-resistant adhesive insulating coating according to (1), comprising one or more selected from siloxane polymers.

(10) A magnetic steel sheet with a heat-resistant adhesive insulating coating, having the coating according to (1) on at least one side of the steel plate.

(11) The electrical steel sheet with a heat-resistant adhesive insulating coating according to (10), wherein the thickness of the heat-resistant adhesive insulating coating is 0.5 m or more and 20 m or less.

(12) An iron core using a magnetic steel sheet with a heat-resistant adhesive insulating coating according to (10)

(13) After laminating and pressing and fixing the electrical steel sheets described in (10) to produce an electrical steel sheet laminate, annealing is performed at 600 to 900 to obtain an integrated iron core. A method of manufacturing an iron core using a coated electromagnetic steel sheet.

(14) At least at the stage of pressure fixation, either heat and adhesively fix, or fix by caulking or jig, or use these together, with heat-resistant adhesive insulating coating according to (13) An iron core manufacturing method using electrical steel sheets.

In the present invention, the composition of the insulating coating of the electrical steel sheet is combined to exert two types of adhesive performance. As specific means, the measurement was performed by a resin that softens at room temperature to 300 and below and differential thermal analysis. It is a film containing a low melting point inorganic component having a softening point temperature of 1000 or less. The coating resin is softened during heat pressing and the iron core is bonded and integrated. The low melting point inorganic component fulfills the function of maintaining the core in a unified state when the core is strain-relieved. Brief Description of Drawings

Figure 1 shows a typical differential thermal analysis curve for glass.

Figure 2 shows a ladder-like siloxane polymer. BEST MODE FOR CARRYING OUT THE INVENTION

In order to remove the strain from the steel sheet, an annealing temperature of about 700: to 800 ° C is usually required. At these annealing temperatures, organic matter decomposes and the structure cannot be maintained, so the adhesion cannot be maintained. The inventors considered that an inorganic compound is suitable for maintaining the structure even at a high temperature of 700 to 800 ° C and exhibiting adhesion between the steel plates, and studied various inorganic compounds. As a result, a group of low-melting-point inorganic components called so-called low-melting-point glass frits and low-melting-point inorganic components such as water glass and colloidal sill force show good adhesion between steel plates in the vicinity of annealing temperature condition 750. I found. However, these low-melting-point inorganic components alone cannot achieve the integral holding of the iron core because the bonding ability is not exhibited at the stage before annealing is completed. Therefore, it has been found that by combining a resin with these, an iron core can be obtained which can be bonded and fixed before the strain relief annealing and can maintain the adhesive fixing ability even after the strain relief annealing.

Hereinafter, the low melting point inorganic component will be described first. The inventors have found that it is the softening point temperature of the low-melting-point inorganic component that dominates the adhesiveness in the strain relief annealing temperature range.

The details of the experiments conducted to complete the invention are described below. In order to confirm the importance of the above-mentioned softening point temperature, the inventors prepared a sample under the following conditions and investigated its adhesive strength. First, we prepared many non-oriented electrical steel sheets with a thickness of 0.5 mm and no insulating coating on the surface. On the other hand, as low-melting-point inorganic components, the average particle size is 5 m and low-melting-point glass frits with various softening point temperatures. As the resin, epoxy resin: acrylic resin: phenolic resin = A 15: 3: 3 (mass%) water emulsion solution having a solid fraction of 20 mass% was mixed, and both were mixed and coated using a mouth-ruko overnight. The mixing ratio of the resin to the glass frits was 100% in terms of solid content, that is, the same mass. The coating amount was 8 g / m ² per side, and the film was dried at a plate temperature of 160. A test piece was cut out from the sample thus prepared. Next, 250 adhesive strength and 750 adhesive strength were measured.

Here, the softening point temperature is the fourth inflection point temperature observed after the start of measurement in the differential thermal analysis measurement curve shown in Fig. 1, or JI S-R3 103-1 “Glass The softening point test method ”(I SO 7884-6: 1987, ASTM C33 8), whichever is the lower temperature. If any of these methods are difficult to measure, replace with another softening point temperature. Also good.

In addition, the 250 ° C adhesive strength refers to the addition of two specimens with a length of 10 cm in the rolling direction and a length of 3 cm perpendicular to the rolling direction, with the short side overlapped by l cm and the area of 3 cm ^2. It is the value obtained by dividing the strength when it was pulled and peeled at room temperature after bonding, under the conditions of pressure 10kg / 3cm ² , heating temperature 250 ^, heating time 60 seconds, by area 3cm ² . In the present invention, the applied pressure and the adhesive strength are values obtained by dividing the indicated value (kg) of the spring rod by the area and are expressed as kg / cm ² , which corresponds to 9.8 × 10 ⁴ Pa.

In addition, the adhesive strength at 750 is the sample bonded under the above-mentioned low temperature bonding conditions, and further heated under the conditions of a heating temperature of 750 and a heating time of 2 hours without applying pressure, and then pulled in the rolling direction at room temperature. When peeled This is the value obtained by dividing the strength of by the area 3 cm ² . The results are shown in Table 1.

table 1

Condition Composition (mass%) Softening point Adhesive strength: kg / cm ² No. B ₂ 0 ₃ Si0 ₂ ZnO A1 ₂ 0 ₃ BaO MgO κ ₂ ο Bi ₂ 0 ₃ SnO PbO Temperature 250T: 750:

1 50 1-------50 300 30 3

2 1 ― ― ― ― ― ― ― 50 50 ― 350 40 5

3 15 5 1----80--1 40 (TC 30 8

4 25-15 15 5 30 10 ― ― ― ― ― 525 20 7

20 20 ― 5 55 ― ― ― ― ― One 675 30 6

6 20 70 ― ― ― ■ ― 10 ― ― ― 760 40 7

7 50 ― 10 15 15 10 ― ― ― ― 880 20 3

8 ― 50 ― 35 ― 15 ― ― ― ― 1000 10 1

9 ― 45 ― 40 ― 15 ― ― ― ― One 1050 10 Not adhered

From Table 1, Condition No. 1 to Condition No. 8, and when using a glass frit with a softening point temperature of 1000 or less, the bond strength is 250 kg and the bond strength is 10 kg / cm ² or more, and 750 bond strength is 1 kg. and / cm ^2, this both values are good Togawakaru. On the other hand, when a glass frit with a softening point temperature of 1050 in condition number 9 is used, the bond strength is good at 250 and 10 kg / cm ² , but at 750 the bond strength is easily peeled off after annealing. It was so weak that it could not be measured. From the above, when using the following glass frit with a softening point temperature of 1000, the adhesive strength is 10 kg / cm ² or more at 250, and the adhesive strength is lkg / cm ² at 750. It turned out to be.

Next, the inventors consider the following mechanism for the reason why the adhesive strength at 750 depends on the softening point temperature of the low melting point inorganic component. 250: During pressure and heat bonding near the resin, the resin softens and melts, and in the case of double-sided coating, the film interface disappears and adhesion between the films is achieved. However, at this stage, the low-melting-point inorganic component having high temperature stability hardly causes the reaction. Next, when heated at 750, the low melting point inorganic component softens and then melts depending on the low melting point inorganic component species, and the low melting point inorganic components coming into contact with each other are bonded together. As a result, the opposing coatings are integrated, and the adhesion between the steel plates is completed. Therefore, it is important that the low-melting-point inorganic component softens or melts in the heating stage near 750 ° C.

As in Condition No. 9 in Table 1, the low melting point inorganic component with a high softening point temperature does not progress in the temperature range of 750, even if the low melting point inorganic components are in contact with each other. A sufficient contact area cannot be obtained between inorganic components. Therefore, the bond between the low melting point inorganic components is not sufficiently formed. As a result, the adhesive strength cannot be obtained. On the other hand, as shown in Condition No. 1 to Condition No. 8 in Table 1, in the low melting point inorganic component having a low softening point temperature, if the low melting point inorganic components are in contact with each other, Since softening proceeds in the temperature range of 750, a constant contact area can be obtained between the low melting point inorganic components. Therefore, a bond between the low melting point inorganic components is formed. As a result, adhesive strength can be obtained.

The reason why a certain 750 adhesive strength can be obtained even for low-melting-point inorganic components with a softening point temperature higher than 750, which is a heating temperature of 880 or 1000, has not been fully elucidated. Even with a low melting point inorganic component with a spot temperature of 880 T: or l OOO:, some kind of softening-like reaction takes place in the temperature range of 750, and the low melting point inorganic components are bonded to each other, and the film is integrated and the steel sheet is bonded. I guess that.

The adhesive strength of 10 kg / cm ² or higher at 250 is defined as the adhesive strength that can be handled without peeling in the manufacturing process after temporary fixing by low-temperature bonding and until final fixing. . In addition, the adhesive strength of 1 kg / cm ² or higher at 750 stipulates the adhesive strength that does not peel after being installed in electrical equipment.

As the low melting point inorganic component of the present invention, a low melting point glass frit, water glass or a mixture of these colloidal silicas can be used.

When the low-melting-point inorganic component to be used is an inorganic powder, its particle size is also important. If the particle size is too large, coarse protrusions will be formed on the surface of the film, preventing contact between the films. In order to achieve sufficient contact between coatings or powders, it is desirable that the average particle size of the low-melting-point inorganic component to be used is 20 mm or less. In particular, it is desirable that the average particle size is 4 w m or less, and further 3 m or less.

Next, the present inventors examined the mixing ratio of the low melting point inorganic component and the resin.

First, we prepared a number of non-oriented electrical steel sheets with a thickness of 0.35 mm and an insulating coating mainly composed of magnesium chromate on the surface. On the other hand, As a low melting point inorganic component, a low melting point glass frit (B ₂ 0 ₃ = 30% Si 0 ₂ = 20% Ba0 = 30% Na ₂ 0 = 10% Zn0 = 10%) and an epoxy resin: acrylic resin: phenolic resin = 20: 5: 3 (mass%) and a 20% by weight solids liquid mixture are mixed and a rollco is used. And applied. At this time, the mixing ratio of the resin to the glass frit was adjusted to various values. The coating amount was adjusted to 5 g / m ² per side and dried at a plate temperature of 150. A test piece was cut out from the sample thus prepared. The bond strength and 750 bond strength were then measured at 250. The results are shown in Table 2.

Table 2

From Table 2, Condition No. 2 to Condition No. 6, that is, when the resin / glass frit mixing ratio is 20% or more and 500% or less, the adhesive strength is 250 and the adhesive strength is 10 kg / cm ² or more, and the adhesive is 750. It can be seen that the strength is lkg / cni ² and both values are good. On the other hand, when the resin / glass frit mixing ratio of Condition No. 1 is 10%, the adhesive strength is 250 kg and the adhesive strength is kg / cm ² 750, and the adhesive strength is 0.5 kg / cm ² . Also, under condition No. 7 where the resin / glass float mixing ratio is 700%, the 250 bond strength is 40kg / cm ² Although preferred, 750 adhesion was as low as 0.5 kg / cni ² . From the above, it was found that both the adhesive strength and the adhesive strength at 750 ° C were good at 250 when the resin / glass frit mixing ratio was 20% to 500%.

The present inventors consider the following mechanism for the reason why the adhesive strength depends on the resin ratio to the low-melting-point inorganic component. Resins share the adhesive function when heated at 250 ° C, and the low melting point inorganic component is 750 ", and share the adhesive function when heated. Therefore, at each heating temperature, both are able to exert their functions. It is possible to infer the mechanism of the resin / low-melting-point inorganic component ratio dependence on the adhesive strength by examining whether there is an organic resin that performs an adhesive function when heated at 250, or at 750. The strength is 750, and the surface occupancy of each low melting point inorganic component that performs the adhesive function when heated can be considered.

When the ratio of the resin to the low melting point inorganic component is small, for example, in the case of condition number 1 in Table 2, the low melting point inorganic component occupies most of the surface, and the resin is almost visible on the surface. Absent. In this state, even if the coatings are overlaid and pressurized, even if heated at 250, a sufficient contact area cannot be obtained between the resins, so there is sufficient resin to achieve adhesion between the coatings. Cannot function. Therefore, the adhesive strength at 250 ° C is a small value (in the case of condition number 1, 250 and adhesive strength = 5 kg / cm ² ). When heating is performed at 750 in a state where sufficient adhesion is not realized at 250, heating is performed at 750, and even if the low melting point inorganic component softens and melts, contact between the coatings is not sufficiently realized at 250 heating. Contact and bonding between low melting point inorganic components cannot be realized sufficiently. As a result, the adhesion strength at 750 ° C also becomes a small value (in the case of condition number 1, 750: adhesive strength = 0.5 kg / cm ² ). Due to this mechanism, if the resin ratio is too small relative to the low melting point inorganic component, the adhesive strength is 250 and 750 ° C. Both show low values.

On the other hand, when the mixing ratio of the resin to the low-melting-point inorganic component is large, the resin is sufficiently present on the surface of the film, and the resin performs a sufficient adhesion function when heated to 250, so that a large adhesive strength can be obtained ( For condition 7, 250: Adhesive strength = 40 kg / cm ² ). However, when 750 is heated, the low melting point inorganic component that should exhibit the adhesive function is not sufficiently present on the coating surface, so the 750 adhesive strength becomes small (in the case of Condition No. 7, the adhesive strength = 0 at 750) 5kg / cm ² ).

Note that by the following linear thermal expansion coefficient at 300 ° C from 30 ° C low-melting inorganic component 1 ox io- ⁷ (Li or ^{^{1 50 X 1 0- 7 rc- 1}} ), the magnetic during core form Variations in characteristics can also be prevented.

The inventors prepared a coated steel sheet and an iron core made of the steel sheet under the following conditions, and investigated the magnetic properties. First, a number of non-oriented electrical steel sheets having a plate thickness of 0.5ππη and having no insulating coating on the surface were prepared. On the other hand, as the low melting point inorganic component, the average particle size is 5 ^ m, low melting point glass frits with various thermal expansion coefficients, and the resin composition is epoxy resin: acrylic resin: pheno — Resin resin = 10: 4: 5 (A mixture of 20% by weight water emulsion solution with a solid content of 20% by weight was applied using a roll coater. The mixing ratio of the resin to the glass flakes is the solid content ratio. The coating amount was adjusted to 1 Og / ra ² per side and dried at a plate temperature of 150.

From these samples, the inner diameter 10. 16cm (4 Lee inches), to produce a-ring-shaped sample having an outer diameter of 1 2. 7 cm (5 I inch), pressure 10 kg / cm ² in a stacked state 20 sheets, the temperature Heated at 250 for 4 hours to produce a film-bonded iron core. Next, the iron core was annealed at 750 ° C. for 2 hours without pressing. Finally, the iron loss value was measured at a frequency of 50Ηζ and a magnetic flux density of 1.5 Tesla. The results are shown in Table 3. Table 3

Condition Composition (mass%) Linear thermal expansion coefficient Iron core loss No. Si0 ₂ ZnO A1 ₂ 0 ₃ BaO MgO K ₂ 0 Βί ₂ 0 ₃ SnO PbO OC-Li (W / kg)

1 45 30 ― ― ― 25 ― ― ― One 160X10- ⁷ 3.27

2 ― ― ― ― ― ― ― 45 55 One 150X10- ⁷ 3.08

3 ― ― 20 ― ― ― ― ― 40 40 One 135X10 ' ⁷ 3.03

4 10 5 ― ― ― ― One 85 ― ― One 105X10 ' ⁷ 3.05

5 20 15 ― 5 60 ― ― One ― One ― 90X10 '' ⁷ 3.07

6 45 One 15 10 20 10 One ― ― One 80X 10 '' ⁷ 3.02

7 55 One ― ― ― ― ― One ― 45 55X10― ⁷ 3.06

8 25 65 ― ― ― ― 10 ― One ― 30X10 '' ⁷ 3.04

9 ― 45 ― 40 ― 15 One one ― One ― 10X10- 7 3.09

10 ― 100 ― ― ― ― 1 1 1 5X10- 7 3.26

Table 3 Condition No. 2 under the conditions No. 9, linear thermal expansion coefficient at 300 from 30 of the low-melting inorganic component 10X 10- ⁷ (in - ¹⁾ When more 150X 10- ⁷ (or less, after annealing iron loss 3.1 (W / kg) yo Ri seen it is rather small good when core form the other hand, the linear thermal expansion coefficient of the condition number 1 160X 10- ⁷ (in - ^1). Garasufuri Tsu City of When iron is used, the iron loss value is 3.27 (W / kg), and condition number 10 has a linear thermal expansion coefficient of 5X 1 (J- ⁷ (de- ¹ )). loss value was as large as 3.26 (W / kg) from the above, the linear thermal expansion coefficient at 300 to 30 of the low-melting inorganic component lox 10- ⁷ (in - ^1). or more 150x 10- ⁷ (r ¹

) It was found that the iron loss in forming the iron core after annealing was good when

Regarding the reason why the iron loss in the iron core after annealing depends on the linear thermal expansion coefficient of the low melting point inorganic component, the present inventors consider the following mechanism. Pressurization / heating adhesion at 250 ° C softens and melts the resin in the coating, and in the case of double-sided coating, the coating interface disappears and adhesion between coatings is realized. However, at this stage, the low-melting-point inorganic component with high temperature stability hardly reacts. Next, when heated at 750 ° C., the low-melting-point inorganic component softens this time, and depending on the low-melting-point inorganic component species, it melts and the low-melting-point inorganic components coming into contact with each other are bonded together. As a result, the opposing coatings are integrated, and the adhesion between the steel plates is completed. And after cooling to room temperature, the iron loss value is measured. What should be considered here is the problem of stress generated in the formed iron core when the steel sheet surface is fully bonded in the high temperature state of 750 and cooled to room temperature.

In general, the magnetic properties deteriorate when stress acts on the iron core. First, the relationship between the thermal expansion coefficient and stress of the substance will be described. In general, when a substance with a large coefficient of thermal expansion and a substance with a small coefficient of thermal expansion are bonded at a high temperature and cooled to room temperature, a substance with a large coefficient of thermal expansion has a tensile stress. However, compressive stress acts on materials with small thermal expansion coefficients. Linear thermal expansion coefficient of the electromagnetic steel sheet is also non-oriented electrical steel sheet oriented electrical steel sheet is a contact about 100x 10- ⁷ (tr ^1). On the other hand, the thermal expansion coefficient of the low-melting non-machine components used in the experiment 5X 10- ⁷ (T ¹⁾ from 160X 10- ⁷ (- ¹⁾ Ru der. Therefore, tensile stress acts on the formed iron core when using inorganic powder with a smaller thermal expansion coefficient than steel sheet, and compressive stress when using inorganic powder with larger thermal expansion coefficient than steel sheet. It will be.

Considering this experiment, in the case of inorganic powder having the largest linear thermal expansion coefficient in condition number 1, a large compressive force is exerted on the formed core, and the smallest linear thermal expansion coefficient in condition number 10 In the case of inorganic powders with a large tensile stress, it is estimated that a large tensile stress acts on the formed iron core. Because of the difference in the coefficient of linear thermal expansion between the steel sheet and the steel sheet, it is assumed that the largest stress is generated. It is thought that was large. On the other hand, in the case of Condition No. 2 to Condition No. 9, the thermal expansion coefficient of the inorganic powder used was different from that of the steel sheet, but the difference was small, so the tensile stress and compressive stress on the formed iron core were similar. Even if it works, the value is small, and as a result, it can be estimated that the iron loss value did not have a significant effect.

The low-melting-point inorganic component of the present invention contributes to the development of adhesiveness after strain relief annealing, and is preferably a low melting point glass having a softening point of 750 or less, which is a normal strain relief annealing temperature. The low-melting glass can be softened and melted during strain relief annealing and solidified by cooling, and the two plates can be bonded after strain relief annealing. The composition of low melting glass is Si0 ₂ -B ₂ 0 ₃ -R ₂ 0 (R is alkali metal), P ₂ 0 ₅ -R ₂ 0 (R is alkali metal), Si0 ₂ -Pb0- B ₂ 0 ₃ series, B ₂ 0 ₃ -B i ₂ 0 ₃ series, S i 0 ₂ -B ₂ 0 ₃ -ZnO series, SnO- P ₂ 0 ₅ series, S i 0 ₂ -B ₂ 0 ₃ -Z r 0 ₂ And the like. In particular, the Si 0 ₂ -B ₂ 0 ₃ -R ₂ 0 (R is alkali metal) system is preferable because it is lead-free and has high adhesion after strain relief annealing.

The low melting point inorganic component may be added as a liquid like water glass. The water glass is particularly preferably soda silicate. The advantage of using water glass is that it does not contain powder particles, so there is no unevenness due to particles on the coated surface, and it is easy to obtain a smooth surface.In particular, when using silicate soda, Adhesive strength after strain relief annealing 1. High strength over OMPa

, /-Degree is obtained. In addition, when potassium silicate is used, a high strength of 4.0.7 OM Pa can be obtained as the bond strength for strain relief annealing.

As the low-melting-point inorganic component of the present invention, it is possible to use a material obtained by further mixing the above-mentioned inorganic component with colloidal silica. By mixing colloidal U force, etc., the viscosity when machine components are softened during strain relief annealing can be adjusted. ΠSilicier force also remains in the membrane even if it remains unsoftened during strain relief annealing. It functions as an aggregate and can increase the bond strength after strain relief annealing.

As a resin applicable to the present invention, a thermosetting resin that causes a curing reaction when the steel sheets are bonded together by pressing and heating, such as phenol resin or epoxy resin, can be applied. A thermoplastic resin that does not cause a curing reaction even when heated, such as a ril resin or a methacryl resin, can be applied. Either thermoplastic or thermosetting resin can be applied, but it is desirable to have an adhesive action.

The resin of the present invention softens at room temperature or more and 300 or less, but considering blocking properties, it is preferably 50 or more, 80 or more, 100 or more, especially 120 to 300 ° C or less. It is preferable to soften to such an extent that fluidity is exhibited. The softening to such an extent that fluidity is exhibited is that the viscosity is 1 xl 0 ⁸ dPa s or less. Baking on steel plate surface As a mechanism of softening by the following heating with a resin strength of 300 cured by heating, there is a case where the cured resin is a thermoplastic resin and the temperature force at which the thermoplastic develops is 300 or more and the following. .

As a softening mechanism when the resin is thermosetting, there is a case where it is softened to a rubber state or a fluid state by heating to a temperature higher than the glass transition temperature. In particular, in the case of a resin cured by baking at a low temperature of 200 or less for a short time of several tens of seconds or less, the resin undergoes a glass transition while softening once through a cross-linking reaction that forms a three-dimensional skeleton by heating. Furthermore, when heated to a high temperature, the cross-linking reaction may proceed again to be cured.

The acrylic modified epoxy resin emulsion previously incorporated with a latent curing agent used as the resin of the present invention is an epoxy resin obtained by compounding a latent curing agent with an epoxy resin and then chemically reacting the acrylic resin. And a mixture of latent hardeners and emulsions. The epoxy resin here refers to a resin having two or more epoxy groups in the monomer, and includes bisphenol A type, bisphenol F type, bisphenol AD type, naphthenic type, phenol novolac type, There are orthocresol novolac type, glycidyl ester type, alicyclic type, etc. As latent curing agents, dicyandiamide, melamine, organic acid dihydrazide, amine amide, keramin, tertiary amine salt, imidazole salt, boron trifluoride amine salt, microcapsule type curing agent And molecular sieve type curing agents. The acrylic resin is transformed into a mixed system of the above epoxy resin and epoxy resin curing agent.

The term “modification” as used herein means that the acrylic resin is chemically bonded to the surface of the epoxy resin and epoxy resin curing agent mixture. Examples of acrylic resins used for such modification include maleic acid, methacrylic acid esters, acrylic acid, acrylate esters, styrene, and acetic acid. It is a polymerized or copolymerized one or more of vinyl. The mixing ratio of epoxy resin and latent epoxy resin curing agent varies greatly depending on the type of epoxy resin and the type of curing agent, but usually 0.05 to 2 parts by mass is appropriate for 1 part by mass of epoxy resin. It is. It is essential that a liquid mixture mainly composed of acrylic-modified epoxy resin emulsion pre-blended with a latent curing agent is baked in an incomplete state after being applied to the surface of the steel sheet. There is no sticking or blocking, and it is in a state where it is bonded by pressing and heating after shearing and laminating. Usually, it can be baked in an incomplete state by drying at a furnace temperature of 100 to 300 for 10 to 90 seconds.

Furthermore, a siloxane polymer can be used as a resin that is softened by heating. Siloxane polymers are polymers whose main skeleton is composed of inorganic Si-0-Si bonds. Si, like C, like Si-CH ₃ , Si-C ₆ H ₅ , Si-H, Si can be directly chemically bonded to organic groups and H, so organic groups and H A siloxane polymer having a modified skeleton can be obtained.

Of the four bonds of Si, one forms a Si-R (R is an organic group or H) bond, and the remaining three are Si-0 bonds. Among the T nuclei, those with three forces that are bonded to Si through 0, that is, Rsi (_0-Si) ₃ are called T 3 nuclei. Si nuclides can be examined by 匪 R. In general, Si nuclei that form siloxane polymers include D nuclei and Q nuclei in addition to T nuclei. The D nucleus is one in which four of Si's four bonds form Si-R (R is an organic group or H) bond, and the remaining two are Si-0 bonds. Q nucleus is a Si-0 bond in four of Si's four bonds.

When Si in the T3 drawing repeats bonding according to a certain rule, a ladder molecule as shown in Fig. 2 is formed. A polymer composed of ladder-like molecules causes entanglement of ladder-like molecule chains by coating and baking, and a hardened surface state with no stickiness or blocking is obtained. Molecular chains that have been entangled at 100 ° C or higher will break and become fluid. As long as fluidity is exhibited, Si nuclei to which epoxy groups are bonded may be included in addition to Si nuclei to which methyl groups are bonded.

The siloxane polymer of the present invention is obtained by hydrolysis in the presence of one or both of organotrialkoxysilane and organotrichlorosilane in the presence of a hydrochloric acid catalyst. Organotrioxyxyfun can be selected from the group consisting of 卜卜卜 xylan, 卜メ卜シランシラン卜卜卜卜卜卜メチルメチルメチルメチルメチルメチルメチルメチルメチルメチル卜卜卜卜卜卜Xy silane, pill pills, xy silane, isobutyl dimethyl silane, isopropyl silane, xy silane, phenylene silane, xy silane, phenyl silane xy silane, methoxy lip lip lip oxime silane , Methacryloxypropyl triethoxysilane, guanidopropyl pill 卜 methoxysilane, glycidopropyl U ethoxysilane, aminopropyl trimethoxysilane, amino □ pill 卜 U ethoxysilane, etc. . Examples of the organochloro-P silane include methyl trichlorosilane, ethyl trichlorosilane, and phenyl trichlorosilane.

One or both of organotrialkoxysilane or organotrimethyl □ D silane may be hydrolyzed after being dispersed in an organic solvent. Solvents include methanol, ethanol, ethanol, and bueno.

,

Various alcohols such as ruthenium, acetone, toluene, xyleno, etc.

,

be able to. The mass ratio of the organic solvent to the organoalkoxysilano at the time of hydrolysis is preferably 1: 0.5 to 1: 2. Hydrolysis is performed by adding 0.1 to 1 times as much water as the number of moles of all alkoxy groups in the starting material. Add hydrochloric acid as catalyst for hydrolysis

. When organotrichlorosilane is used as a raw material, hydrochloric acid is produced as a by-product when water is added, and hydrolysis is carried out under a hydrochloric acid catalyst without any special treatment. Sometimes it is not necessary.

The hydrolyzed sol is usually converted into a siloxane polymer by promoting the polycondensation reaction by a process such as concentration. Concentration is performed by removing the organic solvent and by-product alcohol, etc. using a rotary evaporator, etc., and the mass of the concentrate is about 15 to 60 of the solution mass before concentration. It is preferable from the viewpoint of expression. As a method other than concentration, an alkoxide such as K0H can be added and refluxed in a nitrogen atmosphere or the like to accelerate the polycondensation reaction and obtain a siloxane polymer. The obtained siloxane polymer is diluted 1.5 to 10 times with an organic solvent or water to make a coating solution. Usually, by baking at 100 to 200 for 15 to 120 seconds, a state of adhesion by pressure heating can be obtained.

It should be noted that the resin and low-melting-point inorganic component in the present invention do not show at least apparent melting in the film of the present invention depending on conditions such as heating and annealing atmosphere, and the grains remain as they are. However, there is no problem in the present invention as long as the bonding function is exhibited by the heating and annealing.

The present invention can be applied to any type of magnetic steel sheet produced by ordinary rolling and annealing, such as a directional magnetic steel sheet and a non-oriented electrical steel sheet, but is particularly applicable to a non-oriented electrical steel sheet for motor cores. If this is the case, the effect can be demonstrated most.

In the normal manufacturing method of grain-oriented electrical steel sheets and non-oriented electrical steel sheets, a surface coating is formed on the steel sheet surface by finish annealing for both steel sheets. In the case of grain-oriented electrical steel, a phosphate-based film containing a silica component is formed. In the case of non-oriented electrical steel, a chromate-based film is formed. In particular, in the case of grain-oriented electrical steel sheets, a manufacturing method that forms a film mainly composed of forsterite silicate during finish annealing, a manufacturing method that does not intentionally form the film, and a forsterite film that has been formed are pickled. There is a manufacturing method that removes by means. The present invention can be applied with or without these various surface coatings.

The magnetic steel sheet with a heat-resistant adhesive insulating coating of the present invention is prepared by applying a coating solution containing a heat-resistant adhesive insulating film composition by a method such as rollco, overnight, burco, dipco, or spray. Apply to steel plate. The coating amount is preferably lg / m ² or more and 30 g / m ² or less, particularly preferably 2 g / m ² or more and 10 g / m ² or less.

The heat-resistant adhesive insulating coating composition is preferably a mixture of a resin and a low-melting-point inorganic component, but it may be a mixture in which both are dispersed in a lump or two layers are separately applied. good. Low-melting-point inorganic components may be dispersed in the form of dots or stripes in the matrix due to organic components, or the organic components may be dotted in the inorganic matrix due to siloxane bonds, etc. It may be dispersed in stripes.

The film thickness is desirably 0.5 m or more and 20 m or less per side. If the film thickness is less than 0.5, it is difficult to sufficiently cover the entire surface of the steel sheet, so that sufficient adhesive strength cannot be obtained. On the other hand, if it exceeds 20 ^ m, the space factor greatly decreases when pressed and heated. End up. Therefore, the film thickness should be 0.5 m or more and 20 m or less.

The coating composition of the present invention is first baked and cured after application to the surface of the magnetic steel sheet so as not to cause stickiness or blocking. After application, the steel sheet with a heat-resistant adhesive insulating coating can be produced by baking at 50 to 200. This process involves punching the iron core May be immediately before the lamination of the iron cores, but it is particularly preferable to apply a so-called pre-coated electromagnetic steel sheet at the time of producing the steel sheets in terms of simplifying the iron core production process. When the steel sheet pieces punched out from the steel sheet into a desired shape are stacked and blocked, the resin is softened by heating to a temperature higher than the baking temperature.

When magnetic steel sheet pieces having the coating of the present invention on both sides are laminated and hot pressing is performed, the resin softened by heating during the hot pressing is integrated, so the magnetic steel sheet pieces can be bonded during cooling. become.

In addition, when the magnetic steel sheet pieces having the coating of the present invention only on one side are laminated in the same direction, the resin component softened by heating spreads uniformly on the surface of the electromagnetic steel sheet pieces without the coating layer of the present invention. Can be glued during cooling. Since high temperature hot pressing results in high costs, the hot pressing temperature is preferably 300 ° C or lower. The pressure of the hot press is preferably 0. IMPa or more and 50MPa or less, and particularly preferably IMPa or more and 20MPa or less. If the pressure of the hot press is low, sufficient adhesion cannot be obtained, making it difficult to integrate as an iron core. When the pressure of hot press is high, the adhesive layer may flow and protrude from the interlayer.

The electromagnetic steel sheet of the present invention can be integrated as an iron core by punching into a desired shape, laminating, pressurizing and heating. After that, even if stress relief annealing is performed as necessary, the adhesion between the laminated steel sheets is maintained. The temperature of strain relief annealing is usually 650 or more and 850 ° C or less, and is often 700 or more and 800 or less.

In addition, since the coating film of the present invention has an adhesive ability without performing annealing such as strain relief annealing, it can be used for an iron core that does not perform strain relief annealing. In other words, it can be used as an adhesive film for both strain relief annealing and non-strain relief annealing. Further, in the case of strain relief annealing, it is possible to use caulking or fixing with a jig together when fixing by pressurization or heating. This

、

Example 1

Acrylic resin: Epoxy resin: Phenolic resin = 10: 4: 3 (mass%) A glass-free resin with a softening point temperature of 450 and various particle sizes in an aqueous resin dispersion with a composition of 20 mass% solid content. A solution containing the tutu was prepared. The resin / glass frits mixing ratio in the liquid containing glass frits was set to 200%. This coating solution has a thickness of 0.5mm and has a coating amount of 6g / m per side using a mouthpiece for a non-oriented electrical steel sheet that has been annealed without an insulating coating on the steel sheet surface. ^Painted to be ² . Then, it was dried at a drying temperature of 150 and cooled. The film thickness per side was 10 m. A specimen having a length of 3 cm in the direction perpendicular to the rolling direction was cut out from the sample thus prepared. Then, two test pieces with a length of 1 cm at the short side and an overlap area of 3 cm ² were heated to 250 with pressure of 10 kg / cm ² , held for 60 seconds, cooled, and bonded at 250 A test piece for strength measurement was prepared. Further, a part of the test piece for measuring 250 ° C adhesion strength was heated to 750 under no load, held for 2 hours, cooled, and a test piece for measuring 750 adhesive strength was prepared. The test piece thus prepared was measured for adhesive strength using a tensile tester. The results are shown in Table 4.

Table 4

From Table 4, in the sample group with the average particle diameter of glass frit of condition number 1 to condition number 5 from 2 tm to 20 m, the bond strength is 250 and the bond strength is 10 kg / cm ² or more, and 750 bond strength is also lkg. / cDi ² or better, but with a glass frit of Condition No. 6 with an average particle size of 25 ^ m, the adhesive strength was measured at 750 ° C with a 250 bond strength of 5 kg / cm ² The value was so small that it was not possible.

The example in which the average particle size of the glass frit is 20 im or less is superior to the comparative example in which the average particle size is 25 m.

Example 2

Acrylic resin: Epoxy resin: Phenolic resin = 11: 3: 4 (mass%) In a resin aqueous dispersion with a solid content ratio of 20 mass% in composition, the composition is B ₂ 0 ₃ = 25 mass%, Si0 ₂ = 65% by weight, with Na ₂ 0 = 10 wt%, 30: from our Keru linear thermal expansion coefficient of 40X 10- ⁷ (in - ¹⁾ to 300 and the liquid formulated with Garasufuri Tsu bets (example) of, In the same aqueous resin dispersion, the composition is B ₂ 0 ₃ = 50% by mass, Si 0 ₂ = 25% by mass, K ₂ 0 = 25% by mass, and the linear thermal expansion coefficient from 30 ^ to 300 is 17 OX 10 " ⁷ ( ¹ ) glass frit (comparative example) was mixed, and all glass frits with an average particle size of 10 m were used. Resin / glass The lit mixing ratio was set to 100% in all cases.

For this non-oriented electrical steel sheet with a coating thickness of 0.5 dragon and a annealed non-oriented electrical steel sheet with a magnesium chromate-based insulation film on the steel sheet surface, the coating amount is 8 g / m per side using a roll coater. ² was applied. Then, it was dried at a drying temperature of 140 and cooled. The film thickness per side was 6 jm. From this to the samples prepared, the inner diameter 10. 16cm (4 inches), to produce a-ring-shaped sample having an outer diameter of 12.7 cm (5 Lee inches), pressure 10 kg m ² stacked state 20 sheets, the temperature 250 And heated for 4 hours to produce a coated adhesive core. Next, the iron core was annealed at a temperature of 750 for 2 hours without being pressurized. Finally, the iron loss value was measured at a frequency of 50 Hz and a magnetic flux density of 1.5 Tesla. The results are shown in Table 5.

Table 5

Table 5, the linear thermal expansion coefficient of the condition number 1 40X 10- ⁷ (in - ¹⁾ for iron loss of the core prepared using a glass Sufuri Tsu City of is good and 3.05 (W / kg) against linear thermal expansion coefficient of the condition number 2 becomes 170X 10- ⁷ (° C- ') iron loss of the core prepared using a gas Rasufuri Uz bets is greater and 3.27 (W / kg) value, good It wasn't. Thus, it can be seen that the example according to the present invention is superior to the comparative example.

Example 3

The following four types of coating solutions were prepared.

Coating solution A

Acrylic modified epoxy resin emulsion containing 20 parts of latent curing agent with 100 parts by weight of water 40 parts by weight, methyl ethyl ketone 5 quality An amount was blended. The glass transition temperature of the resin obtained by applying and baking this coating solution was 104 and softened at 120 or more.

Coating solution B

100 parts by weight of water, 40 parts by weight of acrylic resin emulsion, 40 parts by weight of epoxy resin emulsion, and 4 parts by weight of an amine epoxy curing agent were blended. The resin obtained by applying and baking this coating solution softened at 150 or more.

Coating liquid C

An aqueous solution prepared by mixing 35.3 g of water and 1.04 g of 35% hydrochloric acid was dropped into a liquid for mixing 178 g of methyltrioxysilane and 138 g of ethanol to perform hydrolysis. The hydrolyzed solution was concentrated by using a mouth evaporator until the solvent disappeared at 58. The mass of the concentrate was 30% of the solution mass before concentration. The mass average molecular weight of this concentrate was 10,000. Since this concentrate showed a pliability, it is thought that methyltriethoxysilane was polymerized in the form of a chain polymer. When this concentrate was heat-treated at 70 for 15 minutes, it solidified but at 180 it softened from around. 200 parts by mass of ethanol was blended with 100 parts by mass of the concentrate.

Coating solution D

Disperse 178 g of methyl lyeoxysilane and 152 g of tetramethoxysilane in 270.3 g of 2-ethoxyethanol. A coating solution was prepared by hydrolyzing 36 g of water using 4.8 g of acetic acid as a catalyst. This siloxane polymer was not softened by heating.

In Table 6, the temperature indicated in parentheses after the glass composition in the middle of the coating solution is the glass softening temperature. The glasses listed in Table 6 are all powders with an average particle size of 2 m. In Examples and Comparative Examples, each coating solution is applied to both sides of a non-oriented electrical steel sheet having a thickness of 0.5ππη. It was applied in the evening and baked in a furnace set at 70 for 15 minutes. The coating amount was 7 g / m ² . In any case, there was no stickiness of the film surface after baking. Using two test pieces having a width of 3 cm and a length of 10 cm, a part of the test pieces was overlapped so that the area of the bonded portion was 6 cm ² and hot pressing was performed. Prior to hot pressing, the film applied to areas other than the bonded area was scraped off. Two test pieces were bonded by hot pressing of 200, 1 minute, l OMPa. The strain relief annealing was performed in nitrogen at 750 for 2 hours. The adhesive strength before and after strain relief annealing was evaluated using the shear tensile strength, which is the horizontal strength of the bonded surface. In Comparative Example 1, since the glass had a softening temperature higher than the stress relief annealing temperature, there was no adhesion after annealing. In Comparative Example 2, since the resin is of a type that does not soften by heating, it could not be bonded by hot pressing. Since Comparative Example 3 did not contain a low-melting glass, adhesion after strain relief annealing could not be obtained.

Table 6

⁰ An inorganic / organic mixed treatment liquid mainly composed of magnesium chromate and acrylic resin was applied and baked to provide an insulating film on the surface. Example 4

The following four types of coating solutions were prepared.

Coating solution A

40 parts by mass of an acrylic modified epoxy resin emulsion containing 20% by mass of a latent curing agent and 5 parts by mass of methyl ethyl ketone were blended with 100 parts by mass of water. The glass transition temperature of the resin obtained by applying and baking this coating solution was 104, and softened at Ot: or higher.

Coating solution B

Coating liquid C

Hydrolysis was performed by adding dropwise an aqueous solution containing 35.3 g of water and 1.04 g of 35% hydrochloric acid to a mixture of 178 g of methyltriethoxysilane and 138 g of ethanol. The hydrolyzed solution was concentrated using a rotary evaporator until the solvent disappeared at 58. The mass of the concentrate was 30% of the solution mass before concentration. The concentrate had a mass average molecular weight of 10 000. Since this concentrate showed stubbornness, it is thought that methyltrioxysilane was polymerized in the form of a chain polymer. When this concentrate was heat-treated at 70 for 15 minutes, it solidified, but softened from around 180 ° C. 200 parts by mass of ethanol was added to 100 parts by mass of this concentrate.

In the examples, the coating solutions A to (; were diluted with water, and various water glasses were added to prepare coating solutions. The examples and comparative examples are both surfaces of non-oriented electrical steel sheets with a thickness of 0.5 mm. Each coating solution was applied on a rollco overnight and baked for 15 minutes in an oven set at 70 ° C. The coating amount was 10 g / m ² . In any case, there was no stickiness of the film surface after baking.

Using two test pieces each having a width of 3 cm and a length of 10 cm, a part of the test piece was overlapped so that the area of the bonded portion was 6 cm ² and hot pressing was performed. Prior to hot pressing, the applied film was scraped off other than the bonded area. At 200, two test pieces were bonded by hot press of 1 OMPa for 1 minute. The strain relief annealing was performed in nitrogen at 750 for 2 hours. The adhesive strength before and after strain relief annealing was evaluated using the shear tensile strength, which is the horizontal strength of the bonded surface.

Table 7

1) An inorganic-organic mixed processing liquid mainly composed of magnesium chromate and acrylic resin was applied and baked to provide an insulating film on the surface. Example 5

The coating liquid D described in Example 3 was prepared. To 100 parts by mass of coating solution D, 10 parts by mass of spherical particles of polyester having an average particle diameter of 4 m and a softening temperature force of S 200 were mixed and dispersed. It was applied to a non-oriented electrical steel sheet with a surface coating with an inorganic / organic mixed treatment liquid in a rollco and then baked in a furnace set at 100 for 2 minutes. The coating amount was 10 g / m ² . Two pieces of a test piece having a width of 3 cm and a length of 10 cm were used, and a part of the test piece was overlapped so that the area of the bonded portion was 6 cm ² and hot pressing was performed. Prior to hot pressing, the applied film was scraped off except for the bonding area. 230 :, 1 minute, l Two test pieces were bonded by a hot press of OMPa. The strain relief annealing was performed in nitrogen at 750 for 2 hours. The bond strength before and after strain relief annealing was evaluated using the shear tensile strength, which is the horizontal strength of the bonded surface. The adhesion strengths before and after strain relief annealing were 1. OMPa and 2. IMPa, respectively. Industrial applicability

According to the present invention, after punching or shearing, it is bonded by pressurization and heating, and can be integrated as an iron core. Thereafter, the adhesive ability can be maintained even after further strain relief annealing. It is possible to provide an attached magnetic steel sheet. The iron core can be integrated without welding or caulking, and iron loss deterioration due to welding or caulking can be avoided, and the adhesion and insulation properties are maintained even after stress relief annealing, resulting in excellent magnetic properties. An iron core can be produced.

Claims

1. A heat-resistant adhesive insulating coating comprising a resin having a softening point temperature of room temperature or higher and 300 or lower and a low melting point inorganic component having a softening point temperature of 1000 or lower.

2.250 adhesion strength = 10 kg / cm ² or more, the heat adhesive insulating film according to claim 1, characterized in that the adhesive strength = lkg / cm ² or more on at 750.

Contract

3. linear thermal expansion coefficient at 300 from 30 are 10X 10- ⁷ (in - ¹⁾ or 1

50x 10- ⁷ (Heat resistance adhesive insulating film according to claim 1, wherein the less. Of

4. The heat-resistant adhesive insulating coating according to claim 1, wherein the low-melting-point inorganic component is a low-melting-point glass frit, water glass, or a mixture of them with colloidal silica.

5. The heat-resistant adhesive insulating coating according to claim 4, wherein the low melting point inorganic component has an average particle size of 20 m or less.

6. The heat-resistant adhesive insulating coating according to claim 4, wherein the mixing ratio of the resin to the low melting point inorganic component is 20% or more and 500% or less by mass fraction.

7. The heat-resistant adhesive insulating coating according to claim 4, wherein the low-melting-point inorganic component is Si0 ₂ -B ₂ 0 ₃ -R ₂ 0 series low-melting-point glass (R is an Al metal).

8. The heat-resistant adhesive insulating coating according to claim 4, wherein the water glass is sodium silicate.

9. Resin is a resin that is baked incompletely with a mixed liquid mainly composed of epoxy resin, acrylic resin, phenolic resin, and acrylic modified epoxy resin emulsion containing a latent curing agent. The heat-resistant adhesive insulating coating according to claim 1, comprising one or more selected from the group consisting of loxane polymers.

10. A magnetic steel sheet with a heat-resistant adhesive insulating coating, comprising the coating according to claim 1 on at least one side of the steel plate.

11. The electromagnetic steel plate with a heat-resistant adhesive insulating coating according to claim 10, wherein the film thickness of the heat-resistant adhesive insulating coating is 0.5 m or more and 20 ^ m or less.

12. An iron core using the electrical steel sheet with a heat-resistant adhesive insulating coating according to claim 10.

13. The electrical steel sheet according to claim 10 is laminated and pressure-fixed to produce an electrical steel sheet laminate, and then annealed at 600 to 900: to obtain an integrated iron core. A method of manufacturing an iron core using a coated electromagnetic steel sheet.

14. The electromagnetic wave with a heat-resistant adhesive insulating coating according to claim 13, wherein at least in the pressure fixing stage, heating is performed for adhesive fixing, fixing is performed by caulking or a jig, or a combination thereof is used. A method of manufacturing an iron core using steel plates.