JP2016009710A - Laminated electromagnetic steel sheet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated electromagnetic steel sheet avoiding to punch steel sheets one by one by laminating a plurality of electromagnetic steel sheets, causing no separation of lamination, and additionally having no trouble caused by adhesion of an adhesive to a conveying roll, a mold or the like, and a method for producing the laminated electromagnetic steel sheet.SOLUTION: A plurality of electromagnetic steel sheets are laminated to form a laminated electromagnetic steel sheet, and an adhesive layer having a specific cure degree is imparted on a surface layer and between steel sheets. The laminated electromagnetic steel sheet has an adhesive layer having a maximum logarithmic damping ratio of 0.30 or more and 0.60 or less on one side or both sides of an outermost surface layer, and has an adhesive layer having a maximum logarithmic damping ratio of 0 or more and less than 0.30 between steel sheets.

Description

  The present invention relates to a laminated electrical steel sheet with an adhesive layer that can be bonded by heating.

  Conventionally, iron cores used in electrical equipment, etc. are first formed with an insulating coating on the surface of an electromagnetic steel sheet to reduce eddy currents, then processed into a predetermined single plate shape by punching or cutting, etc. It was manufactured by laminating and fixing by welding or bonding.

  On the other hand, in Patent Document 1, as a method of simplifying the manufacturing process of the above manufacturing method, a coated steel sheet obtained by applying and drying an adhesive that expresses adhesive force by heating and pressurization in advance as an insulating film, A method is described in which an iron core is manufactured by punching or cutting into a predetermined single plate shape, laminating a large number, and finally heating and pressing.

  Patent Document 2 describes a method of manufacturing an iron core by laminating electromagnetic steel sheets coated with a semi-cured adhesive and processed into a predetermined shape, and heating and pressing to cure the adhesive. Yes.

  However, all of these methods require punching steel sheets one by one and then aligning them using a jig or the like and laminating them. On the other hand, in recent years, it has been necessary to reduce the thickness of electromagnetic steel sheets in order to reduce the loss of motors and transformers. As a result, the number of sheets necessary to obtain a predetermined performance has increased. In this case, punching and laminating thin steel sheets one by one, the first is a decrease in productivity and an increase in cost due to an increase in the number of punches, and the second is a mold caused by a thin plate thickness. The problem of wear occurs.

  In addition, in the method of Patent Document 2, since the adhesive handles a semi-cured electromagnetic steel sheet, the adhesive adheres to the transport roll and the punching die, causing trouble.

  Patent Document 3 describes a method of manufacturing an iron core by laminating two or more electromagnetic steel sheets to form a multilayer laminated steel sheet, punching it into a predetermined shape, and then laminating it. Further, as a method of forming a laminate without re-applying an adhesive between the punched laminated electrical steel sheets, the adhesive layer is in an incompletely cured state, and after punching with a punching press molding machine, A method for forming a laminate by heating is described.

  By this method, it is possible to avoid punching thin steel sheets one by one, and it is possible to eliminate a decrease in productivity due to this, but the adhesive is in a semi-cured state (“incompletely cured state” in Patent Document 3). There was a problem that the magnetic steel sheets peeled off during handling and the sheet could not be passed, and there was a problem that the adhesive adhered to the roll and the mold.

Japanese Patent Laid-Open No. 2-208044 JP-A-6-6960 JP 2005-191033 A

  Laminated electrical steel sheet that avoids punching of steel sheets one by one by laminating a plurality of electrical steel sheets, there is no peeling of the laminate, and there is no trouble caused by adhesives adhering to transport rolls and molds And it aims at providing the manufacturing method.

  The inventors have made extensive studies in order to solve the above problems, and as a laminated electromagnetic steel sheet composed of a plurality of electromagnetic steel sheets, by providing an adhesive layer having a specific degree of hardening between the outermost surface and the steel sheet, It has been found that the above problems are advantageously solved. That is, the gist configuration of the present invention is as follows.

  The laminated electrical steel sheet of the present invention is a laminated electrical steel sheet obtained by laminating and bonding a plurality of electrical steel sheets, and has an adhesive layer having a maximum value of logarithmic attenuation of 0.30 to 0.60 on one or both surfaces of the outermost surface. The adhesive layer has a maximum logarithmic decay rate of 0 or more and less than 0.30 between the steel plates.

  In the production method of the present invention, an adhesive is applied to at least one surface of an electromagnetic steel sheet, and after baking, a laminated electromagnetic steel sheet is obtained. Then, an adhesive is applied to one or both surfaces of the outermost surface of the laminated electromagnetic steel sheet. The laminated electromagnetic steel sheet is manufactured by baking.

  The production method of the present invention is characterized in that different adhesives are used in forming the adhesive layer between the steel plates and the outermost adhesive layer.

  Further, the manufacturing method of the present invention is such that after applying an adhesive on at least one surface of the electromagnetic steel sheet and laminating it to form a laminated electromagnetic steel sheet, adhesion different from the adhesive on one or both surfaces of the outermost surface of the laminated electromagnetic steel sheet The laminated electrical steel sheet is manufactured by applying an agent and baking.

  According to the present invention, it is possible to obtain a laminated electrical steel sheet that is free from lamination peeling and has no trouble that an adhesive adheres to a transport roll, a mold, or the like. Moreover, according to the manufacturing method of the laminated electrical steel sheet of the present invention, it is possible to avoid the punching of the steel sheets one by one by laminating and to produce efficiently. Furthermore, the iron core which is excellent in adhesiveness is obtained by using the laminated electrical steel sheet of the present invention.

An example of a cross-sectional view showing the form of the present invention (two and three layers) Diagram illustrating an example of continuous lamination method (in the case of the same adhesive) Diagram illustrating an example of continuous lamination method (in the case of different adhesives)

Electrical steel sheet:
In the present invention, the electromagnetic steel sheet as a material is a steel sheet mainly used for motors and transformers utilizing the electromagnetic properties of the steel sheet, but is not particularly limited to this application, and any conventionally known ones. Fits.

  That is, general cold-rolled steel sheets such as so-called soft iron plates (electric iron plates) and SPCC with high magnetic flux density, non-oriented electrical steel sheets containing Si and Al to increase specific resistance, directional electrical steel sheets, etc. Any can be applied as long as electromagnetic characteristics are utilized. Here, the soft iron plate (electric iron plate) means a steel plate having soft magnetism.

  Regarding the thickness, the effect of the present invention is large when the thickness is 0.30 mm or less per one steel plate, and the effect of the present invention is further increased as the thickness is reduced to 0.20 mm and 0.15 mm. In this invention, it does not prescribe | regulate especially about the pre-processing of the electromagnetic steel plate which is a raw material. That is, although it may be untreated, it is advantageous to carry out a degreasing treatment such as alkali or pickling treatment such as hydrochloric acid, sulfuric acid or phosphoric acid. The present invention can also be applied to electrical steel sheets on which an insulating coating such as a forsterite coating, a phosphate coating, a silica-containing coating, a Si coating cured with a silane coupling agent, or a varnish coating is already formed.

Laminated electrical steel sheet:
For example, as shown in FIG. 2 or FIG. 3, the electromagnetic steel sheet is a steel sheet integrated by stacking, bonding and baking a plurality of sheets at the stage of a steel strip. An example of the cross-sectional view is shown in FIG. 1, and examples of methods for continuously laminating, bonding, and baking are shown in FIGS. In FIG. 1, the upper left side is laminated to form a laminated electrical steel sheet, and an adhesive is applied to both surfaces to form an adhesive layer. When the upper layer right side is further coated with an adhesive on one surface of the outermost surface. The case where an adhesive layer is formed is shown, and the lower part is a case where the number of stacked layers is three. By punching or cutting this into a shape according to the application, a member composed of a plurality of sheets can be obtained by a single process. For example, if two sheets are stacked, the number of times of punching or the like is ½, and if three sheets are stacked, the number is one third. After processing, this member is further laminated and bonded to the number necessary to constitute the iron core to manufacture a transformer or the like.

  In the present invention, in addition to the steps of laminating and bonding the steel plates as described above, baking, and applying and baking the adhesive on the outermost surface (one side or both sides) of the laminated electromagnetic steel plates integrated after lamination Have The degree of baking of the adhesive layer is referred to as “curing degree”, and this value becomes “an index of the degree of progress of the crosslinking reaction of the resin”. The “curing degree” can be known by a mechanical method such as a hardness method, a curlastometer method, a dynamic viscoelastic method, a rigid pendulum type physical property test, a dielectric method, a DSC (differential scanning calorimetry) method, or the like.

Logarithmic decay rate:
In the present invention, by defining the maximum value of the logarithmic decay rate, the degree of cure of the adhesive layer between the outermost single-sided or double-sided adhesive layer and the steel sheet is specified. That is, the laminated electrical steel sheet of the present invention has an adhesive layer with a maximum value of logarithmic attenuation of 0.30 or more and 0.60 or less on one or both surfaces of the outermost surface, and the maximum value of logarithmic attenuation is 0 between steel sheets. It has an adhesive layer of less than 0.30.

  The maximum value of the logarithmic decay rate can be known by a rigid pendulum type physical property test.

  As the rigid pendulum type physical property tester, for example, RPT-3000W manufactured by A & D is used, the logarithmic decay rate from room temperature to 250 ° C. is measured, and the maximum value of the logarithmic decay rate is obtained.

  The logarithmic decay rate is a numerical value obtained from the change in viscoelasticity of the coating film due to the progress of the cross-linking reaction, and the maximum value means the magnitude of the degree of curing due to the cross-linking reaction. Therefore, the maximum value of the logarithmic decay rate increases when the degree of cure is low, and the maximum value of the logarithmic decay rate decreases when the degree of cure is high.

  The logarithmic decay rate can be controlled by changing the type of adhesive used, baking conditions (temperature, time, etc.) and the like. Regarding the baking condition, the higher the temperature and the longer the time, the lower the logarithmic decay rate and the higher the degree of curing.

  When a plurality of electromagnetic steel sheets are left uncured and bonded, there has been a problem that resin adheres to the sheet passing roll and the punching die or the steel sheets peel off. Increasing the degree of cure will reduce the frequency of this problem, but at the same time the degree of cure of the outermost adhesive layer will also increase, making it difficult to adhere after punching, preventing adhesion and peeling of the adhesive, No sufficient improvement was found in the adhesion.

  When the inventors investigated the cause of this point, the degree of cure of the adhesive layer between the steel plates when the same adhesive (resin) and the same adhesive method were bonded together to bond a plurality of electrical steel plates to an uncured state. However, it has been unavoidable that becomes lower than the degree of cure of the outermost adhesive layer.

  Furthermore, as a result of diligent research by changing the bonding method and resin used as an adhesive, the above problems can be solved predominately by setting the degree of cure of the outermost adhesive layer and the degree of cure of the adhesive layer between steel plates to a specific range. I found out that

Outermost adhesive layer:
The maximum value of the logarithmic decay rate on the outermost surface is in the range of 0.30 to 0.60 in order to prevent adhesion of the adhesive to the transport roll, press die, etc., and to secure the adhesion after punching. is necessary. If it is less than 0.30, the adhesion after punching becomes insufficient, and the iron core is insufficiently fixed. If it exceeds 0.60, stickiness occurs and a problem of sticking occurs when the press passes.

Adhesive layer between steel plates:
The adhesive layer between the steel plates does not need adhesiveness after punching, and it is necessary to prevent the adhesive from adhering to a transport roll, a press die and the like and to prevent the steel plates from peeling off. For this reason, the maximum value of the logarithmic decay rate is 0 or more and less than 0.30. More preferably, it is less than 0.25. If it is 0.30 or more, peeling of the steel sheet occurs.

  The adhesive on the outermost surface and the adhesive between the steel plates may be the same or different. One surface and another surface can be the same adhesive or different adhesives. When three or more sheets are laminated, the adhesives between the steel plates can be the same or different. Further, if an adhesive that cures faster than the outermost surface is used between the steel plates, it is possible to increase the degree of curing between the steel plates from the outermost surface even when heated simultaneously. In this case, it becomes possible to form an adhesive layer by applying and baking between both steel plates and at the outermost surface in a single process, thereby improving the production efficiency.

  As the resin for the adhesive layer between the steel plates and on the outermost surface, it can be suitably used as long as the above requirements are satisfied. For example, thermosetting that exhibits adhesive properties such as phenol resin, epoxy resin, urea resin, melamine resin, unsaturated polyester resin, and silicone resin. A suitable resin can be applied.

Method for forming the adhesive layer:
After applying an adhesive to at least one side of the electrical steel sheet and baking it after lamination to form a laminated electrical steel sheet, the adhesive is applied and baked on one or both surfaces of the outermost surface of the laminated electrical steel sheet, so that In this method, an adhesive layer is formed on the surface. For example, an adhesive is applied to one side of two electromagnetic steel sheets, and the coated surfaces are laminated and baked to form a laminated electromagnetic steel sheet (FIG. 2).

  Furthermore, when forming the adhesive layer between the steel plates and the outermost adhesive layer, a method using different adhesives is also included. By applying an adhesive on at least one side of the electrical steel sheet and laminating it to obtain a laminated electrical steel sheet, applying an adhesive different from the adhesive on one or both sides of the outermost surface of the laminated electrical steel sheet and baking it. In this method, an adhesive layer is formed between the steel plates and on the outermost surface (FIG. 3). By using different adhesives in this way, adhesive layers with different characteristics can be formed under the same baking conditions, and both the steel sheets and the outermost surface can be baked in a single baking process, improving production efficiency. Can do.

  As a coating method, various methods such as a bar coater, a roll coater, a flow coater, a spray, and a knife coater that are generally used in industry can be applied. It is also possible to apply a thick layer on one sheet and bond it to another uncoated sheet. It is also possible to apply the adhesive diluted with water, an organic solvent such as alcohol or xylene.

The baking method can be a hot air type, an infrared type, an induction heating type, or the like as usual. The baking temperature may be a normal level, and the ultimate steel sheet temperature may be about 100 to 300 ° C. in a time of 1 to 600 seconds. Moreover, you may bake with a hot press in the laminated state. In the case of hot pressing, heating is performed so that the ultimate steel plate temperature is about 100 to 300 ° C. in a time of 1 to 600 seconds, and the pressure may be about 0.1 to 100 kgf / cm ² . In the present invention, the degree of cure of the adhesive layer can be controlled by changing the ultimate steel plate temperature, holding time, pressure, and the like.

  After making the laminated electrical steel sheet, a laminated electrical steel sheet that can be bonded by further applying an adhesive to the surface of the laminated electrical steel sheet is obtained. The outermost adhesive layer is preferably on both sides of the laminated electrical steel sheet, but depending on the purpose, only one side may be provided. Further, depending on the purpose, only one surface may be applied, and the other surface may be another insulating coating, or an adhesive layer may be overcoated on another insulating coating.

  There is no particular limitation on the thickness of the electromagnetic steel sheet of the present invention, but two or more sheets are laminated and bonded to form a laminated electromagnetic steel sheet. Therefore, in the case of 0.30 mm or less (for example, 0.20 mm or 0.15 mm), the present invention Application of the invention becomes effective. If the plate thickness is 0.30 mm or less, not only is the shape retention improved compared to a single steel plate, it is less likely to be damaged during handling, but it is also necessary to make one iron core of the same size. The number of punches can be reduced and the productivity can be greatly improved. Further, since the plate thickness at the time of processing is increased, the die clearance can be increased, and the die life can be extended. In addition, since processing with large distortion such as caulking, welding, and bolting can be avoided, the magnetic characteristics can be greatly recovered.

  The thickness of the outermost adhesive layer of the present invention is not particularly defined, but is preferably 0.1 μm or more and 50 μm or less on average. More preferably, it is 0.5 μm or more and 20 μm or less. If it is 0.1 micrometer or more, adhesiveness will not fall, and if it is 50 micrometers or less, powder blowing can be prevented. Furthermore, if it is 20 micrometers or less, a space factor will not fall.

  The thickness of the adhesive layer between the steel plates is not particularly defined, but is preferably 0.1 μm or more and 20 μm or less on average. More preferably, it is 0.5 μm or more and 10 μm or less. If it is 0.1 μm or more, the adhesion does not decrease, and if it is 20 μm or less, the space factor does not decrease.

  If it is said preferable range, the thickness of the adhesion layer between the outermost surface and the steel plate may not be uniform.

  Hereinafter, although the effect of the present invention is concretely explained based on an example, the present invention is not limited to these examples.

  As the adhesive for forming the adhesive layer, the resin, model number, and manufacturer's adhesive shown in Table 1 were used without dilution.

  A magnetic steel sheet (sheet thickness: 0.05 to 0.15 mm, width: 200 mm, length: 300 mm) containing Si: 2.80 mass%, Al: 0.30 mass%, and Mn: 0.15 mass% Got ready.

For Invention Examples 1 to 13, 17 and 18, the adhesive between the steel sheets shown in Table 2 is applied to the surface between the two steel sheets. 2 are applied with a bar coater so as to be 2, and the coated surfaces are bonded to each other, heated by a hot press so as to reach the ultimate steel plate temperature shown in Table 2 for 30 seconds, and subjected to pressure bonding at a pressure of 10 kgf / cm ² . A laminated electromagnetic steel sheet consisting of two sheets was allowed to cool to room temperature. Furthermore, after applying the adhesive of the outermost surface adhesive layer shown in Table 2 on both surfaces of the laminated electrical steel sheet with a bar coater so as to have the thickness of the outermost surface adhesive layer shown in Table 2, the reached steel plate temperature shown in Table 2 in 30 seconds It was baked to become Thus, the laminated electrical steel sheet in which the adhesion layer between steel plates shown in Table 2 and the outermost surface adhesion layer were formed was produced. An example of a method for continuously performing the above is shown in FIG.

In Invention Example 16, the adhesive between the steel sheet adhesive layers shown in Table 2 is applied to the surface between the four electromagnetic steel sheets with a bar coater so as to be 1/2 the thickness of the steel sheet adhesive layer shown in Table 2. After coating, the coated surfaces are bonded together, heated by hot press to reach the steel plate temperature shown in Table 2 in 30 seconds, pressed at a pressure of 10 kgf / cm ² , and then allowed to cool to room temperature for 4 sheets A laminated electrical steel sheet made of Furthermore, after applying the adhesive of the outermost surface adhesive layer shown in Table 2 on both surfaces of the laminated electrical steel sheet with a bar coater so as to have the thickness of the outermost surface adhesive layer shown in Table 2, the reached steel plate temperature shown in Table 2 in 30 seconds It was baked to become Thus, the laminated electrical steel sheet in which the adhesion layer between steel plates and the outermost surface adhesion layer having thicknesses shown in Table 2 were formed was produced.

For Invention Examples 14 and 15, the adhesive between the steel sheet adhesive layers shown in Table 2 is applied to the surface between the three steel sheets, so that the thickness of the adhesive layer between steel sheets shown in Table 2 is 1/2. Coated with a coater, the coated surfaces are bonded together, heated by hot pressing to reach the ultimate steel plate temperature shown in Table 2 in 30 seconds, pressed at a pressure of 10 kgf / cm ² and then allowed to cool to room temperature. It was set as the laminated electromagnetic steel plate which consists of three sheets. Furthermore, after applying the adhesive of the outermost surface adhesive layer shown in Table 2 on both surfaces of the laminated electrical steel sheet with a bar coater so as to have the thickness of the outermost surface adhesive layer shown in Table 2, the reached steel plate temperature shown in Table 2 in 30 seconds It was baked to become Thus, the laminated electrical steel sheet in which the adhesion layer between steel plates and the outermost surface adhesion layer having thicknesses shown in Table 2 were formed was produced.

  For Comparative Examples 1 to 5 and Invention Examples 1 to 16 and 19, an electrical steel sheet on which no insulating coating was formed was used. Moreover, about invention example 17 and 18, the electromagnetic steel plate with a phosphate type insulating coating and the electromagnetic steel plate with a Si type insulating coating were used, respectively.

For Invention Example 19, fast-curing adhesive A: F1 was applied to the surface between the two steel sheets by a bar coater so that the thickness of the adhesive layer between steel sheets shown in Table 2 was 1/2. Two sheets were bonded together by pressure bonding at 25 ° C. and a pressure of 10 kgf / cm ² by a cold press. Adhesive B: E2, which has a relatively slow curing, is applied to both surfaces of the two bonded electrical steel sheets with a bar coater so as to have the thickness of the outermost surface adhesive layer shown in Table 2. It heated so that it might become the steel plate attainment temperature shown. Thus, the laminated electrical steel sheet in which the adhesion layer between steel plates and the outermost surface adhesion layer having thicknesses shown in Table 2 were formed was produced. An example of a method for continuously performing the above is shown in FIG. By using different adhesives in this way, adhesive layers having different characteristics can be formed in a single baking process. That is, it is possible to form both the outermost steel sheet and the outermost adhesive layer in a single baking process, thereby improving the production efficiency.

Moreover, about Comparative Examples 1-4, the adhesive of Table 2 was apply | coated with the bar-coater so that thickness might be set to 3 micrometers on both surfaces of the said two electromagnetic steel plates, it bonded and hot-pressed by Table 30 in time 30 seconds. Heating was performed so that the temperature reached the indicated steel plate temperature, and pressure bonding was performed at a pressure of 10 kgf / cm ² , followed by cooling to room temperature to obtain a laminated electromagnetic steel plate composed of two sheets. At this time, a Teflon (registered trademark) sheet was sandwiched between portions where the press surface of the hot press was in contact with the coated surface of the magnetic steel sheet so that the press surface and the magnetic steel sheet were not bonded. Thus, the laminated electrical steel sheet in which the adhesion layer between steel plates and the outermost surface adhesion layer having thicknesses shown in Table 2 were formed was produced.

  Further, for Comparative Example 5, similarly to Invention Examples 1 to 13, a laminated electrical steel sheet on which an inter-steel sheet adhesive layer and an outermost surface adhesive layer having thicknesses shown in Table 2 were formed was produced.

Table 2 shows the results of examining the coating properties of the laminated electrical steel sheet thus obtained together with the conditions.
<Logarithmic decay rate>
The above-described method was performed using a rigid pendulum type physical property test.
<Steel integrity>
The degree of peeling between the steel plates when bent at 10 mmφ was visually determined.
(Criteria)
◎: No problem without peeling ○: Some peeling parts are seen, but there is no problem in handling △: Separation occurs and can be easily separated by hand ×: Separated into multiple sheets <Adhesive to mold Adhesion>
100 electromagnetic steel plates sheared to a width of 60 mm and a length of 300 mm were laminated and punched into a ring-shaped iron core having an outer diameter of 45 mm and an inner diameter of 35 mm. The clearance at this time was 5% of the laminate thickness. The degree of adhesion of the adhesive to the mold when punching was visually evaluated.
(Criteria)
○: No adhesion ×: Adhered

  As shown in Table 2, all of the laminated electrical steel sheets obtained according to the present invention are superior to the conventional ones in that there is no peeling of the laminate and there is no trouble that the adhesive adheres to the transport rolls and molds. Has characteristics.

  Furthermore, even when the motor core was punched out and subjected to strain relief annealing, the teeth were not peeled off and lifted up, and a good product was obtained.

  By using the laminated electrical steel sheet of the present invention, there is no occurrence of peeling of the laminate, adhesion of the adhesive to the transport roll / mold, etc., and an iron core can be produced with high efficiency and low cost. It is suitably used for motors, transformers and the like.

Claims (4)

  A laminated electrical steel sheet obtained by laminating and bonding a plurality of electrical steel sheets, and has an adhesive layer having a maximum logarithmic attenuation rate of 0.30 or more and 0.60 or less on one or both surfaces of the outermost surface. A laminated electrical steel sheet having an adhesive layer having a maximum value of 0 or more and less than 0.30.   A method of manufacturing the laminated electrical steel sheet according to claim 1, wherein an adhesive is applied to at least one surface of the electrical steel sheet, and after lamination is baked to obtain a laminated electrical steel sheet, one side of the outermost surface of the laminated electrical steel sheet Or the manufacturing method of the laminated electrical steel sheet which apply | coats an adhesive agent to both surfaces, and is baked.   The method for producing a laminated electrical steel sheet according to claim 2, wherein different adhesives are used in forming the adhesive layer between the steel sheets and the outermost adhesive layer.   A method for producing the laminated electrical steel sheet according to claim 1, wherein an adhesive is applied to at least one surface of the electrical steel sheet and laminated to form a laminated electrical steel sheet, and then one or both sides of the outermost surface of the laminated electrical steel sheet. The manufacturing method of the laminated electrical steel sheet which apply | coats the adhesive agent different from the said adhesive agent, and is baked.