Electromagnetic steel laminate

Abstract

The present invention provides an electromagnetic steel sheet laminate having a polymer adhesive layer that can bond (fasten) electromagnetic steel sheets without using existing fastening methods such as welding, clamping, or interlocking, and a manufacturing method thereof. [Solution] A laminate comprising a plurality of magnetic steel sheets and a polymer adhesive layer disposed between the magnetic steel sheets, the polymer adhesive layer having a coating thickness of 1.8 to 5.4 μm, a space factor of the laminate being 95.8 to 98.5%, and satisfying the following mathematical formula 1: [Mathematical formula 1] 172.4≦space factor(%)×thickness(μm)≦531 It is characterized by satisfying the following mathematical formula 2. [Mathematical formula 2] 40≦Shear adhesive strength (MPa) × High temperature adhesive strength (MPa)≦130 (However, high temperature adhesive strength is a value measured at 150℃ according to ISO 4587 standard.)

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic steel sheet laminate, and more particularly to an electromagnetic steel sheet laminate having a polymer adhesive layer formed thereon that can bond (fasten) electromagnetic steel sheets without using existing fastening methods such as welding, clamping, or interlocking. [Background technology]

[0002] Non-oriented electrical steel sheets are steel sheets with uniform magnetic properties in all directions on the rolled sheet, and are widely used in motors, generator cores, electric motors, small transformers, etc. Electrical steel sheets are divided into two types: those that require stress relief annealing (SRA) after punching to improve their magnetic properties, and those that do not require stress relief annealing if the cost loss from heat treatment is greater than the magnetic property benefit from stress relief annealing. Insulating coatings are applied during the finishing process of laminates for motor and generator cores, electric motors, small transformers, etc., and typically require electrical properties that suppress the generation of eddy currents. Other requirements include continuous punching workability, adhesion resistance, and surface adhesion. Continuous punching workability refers to the ability to suppress die wear when multiple laminates are punched into a desired shape and then stacked to form an iron core. The anti-sticking property means the ability of the core steel sheets to not stick together after a stress relief annealing process that removes the processing stress of the steel sheets and restores their magnetic properties. In addition to these basic properties, the coating solution must also have excellent application workability and long-term usability after mixing. Such insulating coatings can only be manufactured on electrical steel sheet laminates using separate fastening methods such as welding, clamping, and interlocking. Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to provide an electrical steel sheet laminate having a polymer adhesive layer that can bond (fasten) electrical steel sheets without using existing fastening methods such as welding, clamping, or interlocking, and a method for manufacturing the same. [Means for solving the problem]

[0004] The electrical steel sheet laminate of the present invention is a laminate including a plurality of electrical steel sheets and a polymer adhesive layer located between the electrical steel sheets, wherein the coating thickness of the polymer adhesive layer is 1.8 to 5.4 μm, the space factor of the laminate is 95.8 to 98.5%, and the laminate satisfies the following mathematical formula 1: [Mathematical formula 1] 172.4≦space factor (%)×thickness (μm)≦531 The laminate may satisfy the following mathematical formula 2. [Mathematical formula 2] 40≦Shear adhesive strength (MPa) × High-temperature adhesive strength (MPa)≦130 (However, high-temperature adhesive strength is a value measured at 150°C according to ISO 4587 standards.)

[0005] The laminate may have a shear bond strength of 4.8 to 17.9 MPa. The laminate may have a high temperature adhesive strength of 5 to 7.2 MPa. The surface insulation resistance of the polymer adhesive layer in the laminate may be 90 to 160 Ω. The inorganic content in the polymer adhesive layer in the laminate may be 5 to 30 wt %. The polymeric adhesive layer in the laminate may have an anti-sticking temperature of 110 to 195°C. The laminate may have an ATF resistance temperature of 150 to 190°C. The tensile adhesive strength of the laminate is 1.2 to 13 N / mm 2 may be.

[0006] The method for producing an electrical steel sheet laminate of the present invention includes the steps of applying a coating composition containing, in solid content, 70 to 95 wt % of resin and 5 to 30 wt % of inorganic nanoparticles of one or more types of SiO2, TiO2, and ZnO to steel sheets, curing the composition by heat treatment, and adjusting the pressure of the bar coater, roll coater, and steel sheets to 50 to 1500 kgf during application of the coating composition to form a polymer adhesive layer on the electrical steel sheets, and laminating the electrical steel sheets with the polymer adhesive layer formed thereon. [Effects of the Invention]

[0007] According to the present invention, the magnetic steel sheets can be bonded without using existing fastening methods such as welding, clamping, and interlocking, and the magnetic properties of the magnetic steel sheet laminate are further improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram of an electromagnetic steel sheet laminate. [Figure 2] 1 is a schematic view of a cross section of an electrical steel sheet laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will now be described in detail by way of example only, and is not intended to limit the scope of the invention, which is defined solely by the scope of the claims set forth below. The present invention provides an electrical steel sheet laminate. The electrical steel sheet laminate according to the present invention includes a plurality of electrical steel sheets and a polymer adhesive layer located between the plurality of electrical steel sheets. Fig. 1 shows a schematic diagram of the electrical steel sheet laminate according to the present invention. As shown in Fig. 1, the electrical steel sheet laminate has a configuration in which a plurality of electrical steel sheets are stacked.

[0010] A schematic cross-sectional view of an electrical steel sheet laminate of the present invention is shown in Figure 2. As shown in Figure 2, an electrical steel sheet laminate 100 of the present invention includes a plurality of electrical steel sheets 10 and a polymer adhesive layer 30 located between the plurality of electrical steel sheets. The electrical steel sheet laminate of the present invention may be a laminate in which different electrical steel sheets are heat-fused together by simply forming a polymer adhesive layer using the adhesive coating composition described above, without using existing methods such as welding, clamping, or interlocking. In this case, the laminate of magnetic steel sheets has excellent high-temperature adhesiveness and high-temperature oil resistance even after heat fusion.

[0011] Each component will be described in detail below. General non-oriented or oriented electrical steel sheets can be used without any restrictions as the electrical steel sheets 10. Since the main component of the present invention is to form polymer adhesive layers 30 between a plurality of electrical steel sheets 10 to manufacture an electrical steel sheet laminate 100, a detailed description of the electrical steel sheets 10 will be omitted. The polymer adhesive layer 30 is formed between the plurality of magnetic steel sheets 10 and has such strong adhesive strength that the plurality of magnetic steel sheets 10 can be bonded together without using existing fastening methods such as welding, clamping, or interlocking. The polymer adhesive layer 30 is formed by coating an adhesive coating composition on the surface, curing it to form an adhesive coating layer, and laminating and heat-sealing the layers. When a plurality of magnetic steel sheets 10 having adhesive coating layers formed thereon are stacked and heat-sealed, the resin components in the adhesive coating layers are heat-sealed to form a polymer adhesive layer.

[0012] Such a polymer adhesive layer contains an inorganic metal compound as a main organic component, and the inorganic component is uniformly dispersed within the organic component in the polymer adhesive layer to form a fine phase. More specifically, the electrical steel sheet laminate has a coating thickness of the polymer adhesive layer of 1.8 to 5.4 μm, a space factor of the laminate of 95.8 to 98.5%, and satisfies the following mathematical formula 1. [Mathematical formula 1] 172.4≦space factor (%)×thickness (μm)≦531.0 Assuming the thickness of the material remains the same, as the coating thickness increases, the space factor generally decreases, which in turn increases the surface insulation resistance. However, since the downward change in space factor due to the coating thickness is not a linear change, adjusting it within the optimal range is an essential part of current market requirements. More specifically, the value of Equation 1 may be 390 to 450.

[0013] More specifically, the laminate may satisfy the following mathematical formula 2. [Mathematical formula 2] 40≦Shear adhesive strength (MPa) × High-temperature adhesive strength (MPa)≦130 (However, high-temperature adhesive strength is a value measured at 150°C according to ISO 4587 standards.) Shear bond strength and high-temperature bond strength are properties that are difficult to improve simultaneously by adjusting the inorganic content and polymer composition. Shear bond strength improves as the polymer resin content in the bonding solution increases and the inorganic content decreases, while high-temperature bond strength improves as the resin content in the bonding solution decreases and the inorganic content increases. However, because shear bond strength and high-temperature bond strength are not linearly inversely proportional to the resin and inorganic content in the bonding solution, adjusting them within the optimal range is essential to meet current market requirements. These seemingly contradictory factors can be adjusted to meet market needs. More specifically, the value of Equation 2 may be between 80 and 130.

[0014] By constructing a laminate that satisfies these requirements, a laminate (core) that can satisfy all of the various properties currently required for EVs can be obtained. The elements are obtained by applying a coating composition containing 70 to 95 wt % of resin and 5 to 30 wt % of inorganic nanoparticles of one or more of SiO2, TiO2, and ZnO to a steel plate, curing it through heat treatment, and adjusting the pressure of the roll coater and steel plate to 50 to 1500 kgf during application of the coating composition, more specifically, 100 to 1200 kgf. The average particle size of SiO2 may be 10 to 30 nm, the average particle size of TiO2 may be 30 to 50 nm, and the average particle size of ZnO may be 70 to 100 nm. The resin may be an epoxy resin, with a weight average molecular weight of 8,000 to 15,000 g / mol and a glass transition temperature of 70 to 90°C.

[0015] Each element will be examined in detail below. Coating Thickness The coating thickness of self-bonding products is between 1.8 and 5.4 μm. If the coating thickness is less than 1.8 μm, the adhesive strength may be poor and dielectric breakdown may occur in the high frequency range. On the other hand, if the coating thickness is too thick, the stacking factor of the motor core may be poor. A more specific range may be 4.0 to 4.5 μm. More specifically, if the coating thickness is less than 1.8 μm, insulation breakdown occurs between the cores when the motor rotates at high speed, reducing motor efficiency. Also, if the coating thickness is 5.4 μm or more, the coating layer becomes too thick, causing the bonding layer to flow out from the side during the motor core assembly process and reducing the space factor of the motor core.

[0016] The coating thickness can be controlled by the physical properties of the bonding solution (specific gravity, viscosity, solid content). When the bonding solution has a specific gravity of 1.05 to 1.4, a viscosity (cps) of 5 to 100, or a solid content (wt.%) of 5 to 50, the coating thickness can be within the above range. The thickness of the coating was measured using a Fourier Transform Infra-Red Spectroscopy (FT-IR) coating thickness measuring device. Infrared spectroscopy is an analytical method that uses the property of molecules to absorb frequencies that correspond to their inherent vibrations, and works by reflecting infrared light off a material and reading the spectrum of detected wavelengths.

[0017] Occupancy factor The stacking factor of self-bonding products is 95.8 to 98.5% based on a material thickness of 0.27mm. It can be adjusted within this range taking into consideration the motor core fastening strength, manufacturing defect rate, motor efficiency, and insulation breakdown. If the space factor is below 95.8%, the coating is too thick, resulting in poor motor efficiency and the risk of bonding solution leaking during the motor core manufacturing process.On the other hand, if the space factor is above 98.5%, the coating is too thin, resulting in poor fastening strength and the risk of dielectric breakdown between cores. The space factor can be controlled by the thickness of the coating applied to the surface of the non-oriented electrical steel sheet. The lamination factor is expressed as a percentage by measuring the lamination coefficient of a specimen made of strips cut from an electrical steel sheet [pressure: 1N / 10.2kgf / cm 2} / {Stacking factor(%)=actual weight / calculated weight(width x length x density x height) x 100}].

[0018] Shear adhesive strength The shear strength of the self-bonding product is 4.8 to 17.9 MPa. The shear strength of the self-bonding product at 180°C is preferably 14.9 MPa to 17.9 MPa to prevent assembly defects due to thermal shock during the motor assembly process. If the shear adhesive strength is lower than the above range, adhesion to the sides and slots of the core is not achieved during the manufacturing of the motor core, which not only causes defects during the motor assembly process but also increases noise and vibration of the motor. On the other hand, if the shear adhesive strength exceeds the above range, the adhesive strength is too high and the core is fused in the mold, making it difficult to separate the core and reducing productivity. The shear adhesive strength can be controlled by adjusting the content of inorganic matter contained in the polymer resin. When the polymer resin contains 0.1 to 60 wt% of inorganic matter based on the total weight percent, the shear adhesive strength within the range can be achieved. In this case, the inorganic matter content may be more preferably 5 to 30 wt%. In this case, the type of inorganic material used is nano-sized SiO 2 , TiO 2 , ZnO It is a single or mixture of two inorganic substances. The shear adhesive strength was measured using a shear tester. Two test pieces (0.27mm thick, 100x25mm) were prepared, and the ends of the test pieces were overlapped by 12.5mm, and then fused under certain conditions (temperature 220°C, pressure 3MPa, time 30 minutes), and the value was measured according to ISO 4587.

[0019] High temperature adhesive strength (150℃ or higher) High temperature adhesive strength (150°C or higher) is a shear adhesive strength of 5 to 7.2 MPa based on 180°C. If the high-temperature adhesive strength (150°C or higher) is 5 MPa or less based on 180°C, not only will the fastening force during manufacturing of the bonding core be poor, but the ATF resistance may also be poor. On the other hand, if the high-temperature adhesive strength is 7.2 MPa or higher, the high-temperature adhesive strength requires heat fusion at a high temperature, which may result in poor workability during manufacturing of the bonding core. High-temperature adhesive strength can be controlled by the type of polymer chain and the coating curing temperature. When the ratio of network or cross-linked polymer chains is 50 to 99% by weight based on 100% by weight of the bonding solution and the curing temperature is 150 to 300°C, the high-temperature adhesive strength within the above range can be achieved. The high-temperature adhesive strength was measured using a Universal Testing System. Two specimens (0.27 mm thick, 100 x 25 mm in size) were prepared, and the two ends of the specimens were overlapped by 12.5 mm and heat-sealed to prepare samples for shear adhesive strength measurement. The prepared samples were then heated to 150°C or higher for 1 minute, and the values ​​were measured according to ISO 4587.

[0020] Surface Insulation Resistance The surface insulation resistance of self-bonding products is 90 to 160 Ω·mm 2 / lam.) or less. If the coating thickness is too thick to ensure high insulation resistance, the stacking factor of the motor core may be poor. If the coating thickness is too thin, insulation breakdown may occur between cores in the case of a drive motor that operates in the high frequency range, resulting in a decrease in motor efficiency. Surface insulation resistance is 90Ω·mm 2 If the surface insulation resistance is less than 160 Ω·mm, insulation breakdown may occur between the cores when the motor rotates at high speed, resulting in a decrease in motor efficiency. 2 If the thickness is more than 1 / 1 lam, the thickness of the coating layer becomes too thick, which may cause defects during the assembly of the motor core and may also reduce the space factor of the motor core.

[0021] The surface insulation resistance can be controlled by the thickness of the coating applied to one side of the self-bonding product and the content of inorganic matter in the coating layer. When the thickness of the coating applied to one side is 1.0 to 6.0 μm, the surface insulation resistance in this range can be met. In addition, when the coating thickness is limited to 1.8 to 5.4 μm, the surface insulation resistance can be satisfied in the above range when the inorganic content is 5 to 30 wt % based on the total weight %. In this case, the type of inorganic material used is nano-sized SiO 2 , TiO 2 , ZnO It is a single or mixture of two inorganic substances. Surface insulation resistance is calculated by calculating the current value measured by a Franklin Insulation Tester using the formula: Ri (insulation resistance) = 645 (1 / I (current mA)) - 1 Ω mm 2 This measuring instrument is a single sheet test device that measures the surface insulation resistance of electrical steel sheets under a constant pressure and voltage (ASTM A717), with a current range of 0 to 1,000 Amp, and is measured under a constant applied pressure (20.4 atm).

[0022] Sticky Resistance Temperature The anti-sticky temperature of the self-bonding product is 110 to 195°C. If the anti-sticky temperature is less than 110°C, the bonding layers may stick together when winding the coil, resulting in poor slitting, punching, and shape quality of the bonding core. On the other hand, if the anti-sticky temperature is more than 195°C, the heat fusion temperature during manufacturing of the bonding core may be too high, resulting in poor motor core productivity. The anti-sticky temperature can be controlled by the glass transition temperature (Tg) of the bonding solution. When the glass transition temperature (Tg) is between -50 and 100°C, the anti-sticky temperature in the range can be satisfied. The anti-sticking temperature was expressed as the temperature at which the test pieces of 0.27mm thick material, laminated to 100mm x 100mm x 10mm, were pressed under 3MPa for 30 minutes and then stuck together.

[0023] ATF (Automatic Transmission Fluid) temperature resistance The ATF resistance temperature is 150 to 190°C. It can be adjusted taking into consideration that the motor is actually cooled by direct / indirect contact with ATF oil. If the ATF resistance temperature is less than 150°C, the fastening strength of the motor core will be reduced due to the ATF oil, which will ultimately increase the noise / vibration of the motor and also reduce its efficiency. On the other hand, if the temperature exceeds 190°C, not only will the ATF oil deteriorate, but the high ATF temperature can also cause the magnet attached to the rotor core to heat up, resulting in demagnetization, which can reduce motor efficiency. The ATF resistance temperature can be controlled by the glass transition temperature (Tg) of the bonding solution. When the glass transition temperature (Tg) is between -50 and 100°C, the ATF resistance temperature can be within the above range. The ATF resistance temperature was defined as the temperature at which the joint strength did not decrease after the bonded specimen was immersed in ATF oil at 180°C for 500 hours. The specimens were manufactured and the joint strength was measured according to the ISO 4587 standard.

[0024] Tensile bond strength The tensile strength of one bonding layer is 1.2 to 13N / mm at room temperature. 2 The following is the result. The tensile adhesive strength of the product is 1.2N / mm at room temperature. 2 If the tensile strength is less than 13N / mm, the fastening force during manufacturing of the bonding core may be poor. 2 In the above cases, the tensile strength may be too high, resulting in poor workability when manufacturing the bonding core. The tensile strength can be controlled by adjusting the bonding core fusion temperature. When manufacturing the bonding core, the heat fusion temperature is 100 to 250°C, and the tensile strength can be within this range. In this case, the required heat fusion pressure is 1.0 to 5 N / mm. 2 is. The tensile strength was measured by a tensile tester at room temperature after heat-sealing at 100°C to 250°C on a 50mm x 50mm x 10mm sample.

[0025] Punching property The punchability of self-bonding products is between 3 million and 5 million punches. If the punchability is less than 3 million hits, the cost of manufacturing the die increases, whereas if the punchability is 5 million hits or more, the height of the motor core burr increases due to increased die wear, which can result in defective motor core shapes. The punchability of the self-bonding product can be controlled by the coating thickness and the inorganic content within the coating layer. The punchability was evaluated for a 0.27mm thick self-bonded product using a die tool specifically designed for electromagnetic steel sheets. The punching evaluation conditions were an 8% clearance, 350 SPM (Spots Per Minute), and 8 hours of work per day.

[0026] curing temperature The curing temperature of the self-bonding product is 100 to 300° C. Taking into consideration the stickiness resistance during coating work and on-site workability, the temperature is preferably 150 to 250° C. If the curing temperature of a self-bonding product is below 100°C, the bonding layers may stick together when winding the coil after in-line coating. On the other hand, if the curing temperature is above 250°C, the bonding layers may deteriorate or harden, resulting in poor fastening strength. To control the curing temperature, the amount of curing agent added to the bonding solution can be adjusted. When the curing agent is added in an amount of 0.01 to 10 wt % based on the total weight %, the curing temperature can be within the above range. The hardening temperature of the self-bonding product was measured by measuring the material plate temperature (PMT: Pick Metal Temperature) using a non-contact TC (Thermocouple).

[0027] Preferred examples and comparative examples of the present invention will be described below. However, the following examples are merely preferred examples of the present invention, and the present invention is not limited to the following examples. [Experimental Example 1] Non-oriented electrical steel sheets (50 x 50 mm, 0.35 mm thick) were prepared as test pieces. The adhesive coating solution was applied to the top and bottom of each prepared test piece at a uniform thickness (approximately 5.0 μm) using a bar coater and a roll coater. The adhesive coating solution was then cured at 220°C for 20 seconds based on the sheet temperature, and then slowly cooled in air to form an adhesive coating layer. The pressure applied to the roll coater and steel sheet during application was adjusted to 1000 kgf. The adhesive coating layer-coated magnetic steel sheets were stacked to a height of 20 mm and then heat-sealed at 120°C for 10 minutes under a pressure of 0.1 MPa. The components of the heat-seal layer and various properties of the heat-sealed magnetic steel sheets are summarized in Tables 1 to 3 below. The composition of the coating solution used here is as follows: The content of the inorganic substance used was adjusted as shown in the table below and tested.

[0028] The components of the bonding solution used are listed below. The resin used in this invention is an epoxy resin with a weight-average molecular weight of 10,000 g / mol and a glass transition temperature of 80°C. The inorganic materials used are SiO2, TiO2, and ZnO, either alone or in combination, with inorganic nanoparticle sizes of SiO2 15 nm, TiO2 40 nm, and ZnO 80 nm, respectively. The weight percentages of the resin and inorganic materials are the weight percentages of the solid content excluding water or solvent contained in the solution.

[0029] [Table 1]

[0030] [Table 2]

[0031] In Comparative Examples 2 and 3, despite the high inorganic content and thin coating thickness, the space factor was low, and the high inorganic content and thin coating thickness resulted in poor shear and high-temperature adhesive strength as well as poor punchability.In addition, Comparative Example 4 was determined to be inappropriate for the invention because the coating thickness was too thick, resulting in poor space factor, high-temperature adhesive strength, and high anti-stick temperature. In addition, in the case of Comparative Example 1, although the coating thickness and space factor were within the preferred range, they did not satisfy the space factor (%) x thickness (μm) range in [Equation 1], and therefore exhibited poor high-temperature adhesive strength, poor surface insulation resistance, and poor tensile strength. This shows that the coating thickness and space factor are not elements that should be controlled independently, and that the downward change in space factor due to coating thickness is not a linear change, so the relationship in [Equation 1] is satisfied, and an excellent laminate can be obtained.

[0032] <Overall rating> (Main criteria for overall evaluation: Shear adhesive strength x high temperature adhesive strength x surface insulation resistance x coating thickness x space factor) As shown in Tables 1 and 2, the self-bonding products and bonding layers related to Examples 1 to 4 all had higher shear and tensile adhesive strength than the self-bonding products and bonding layers related to the comparative examples, and both the high-temperature adhesive strength and resistance were within the appropriate range, resulting in an overall rating of "A" for all of them. Comparative Examples 1 to 4 did not meet two or more of the following characteristics for application to actual motor products: shear adhesive strength, high-temperature adhesive strength, surface insulation resistance, coating thickness, and space factor, and the overall evaluation was also "B," indicating that they were inferior.

[0033] [Experimental Example 2] The same procedure as in Experimental Example 1 was carried out, except that the coating solution composition was as shown in Table 3 below, and the pressure of the roll coater and the steel plate during coating of the coating solution was adjusted as shown in Table 3 below.

[0034] [Table 3]

[0035] [Table 4]

[0036] It can be seen that the Examples are excellent in all properties, whereas Comparative Examples 5 to 8 do not meet two or more of the following properties for application to actual motor products: shear adhesive strength, high-temperature adhesive strength, surface insulation resistance, coating thickness, and space factor, and the overall evaluation was "B," indicating that they are inferior.

[0037] The present invention is not limited to the above-described embodiments, and can be manufactured in various different forms, and a person skilled in the art will understand that the present invention can be embodied in other specific forms without changing the technical concept or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting. [Explanation of symbols]

[0038] 10 Electrical steel sheet 30 Self-bonding layer 100 Electromagnetic steel sheet laminate

Claims

1. A plurality of electromagnetic steel sheets; a polymer adhesive layer located between the magnetic steel sheets, The coating thickness of the polymer adhesive layer is 1.8 to 5.4 μm; The space factor of the laminate is 95.8 to 98.5%, Satisfy the following mathematical formula 1 and the following mathematical formula 2, The shear bond strength of the laminate is 4.8 to 17.9 MPa, The high-temperature adhesive strength of the laminate is 5 to 7.2 MPa, The surface insulation resistance of the polymer adhesive layer in the laminate is 90 to 160 Ω; The polymer adhesive layer comprises, in solid content, 70 to 95 wt % of an epoxy resin and 5 to 30 wt % of inorganic nanoparticles of one or more of SiO 2 , TiO 2 and ZnO. [Mathematical formula 1] 172.4≦space factor (%)×thickness (μm)≦531 [Mathematical formula 2] 40≦shear adhesive strength (MPa)×high-temperature adhesive strength (MPa)≦130 (However, the high-temperature adhesive strength is a value measured at 150°C according to ISO 4587.)

2. 2. The electrical steel sheet laminate according to claim 1, wherein the polymer adhesive layer in the laminate has an anti-sticking temperature of 110 to 195°C.

3. 3. The electrical steel sheet laminate according to claim 1, wherein the laminate has an ATF resistance temperature of 150 to 190°C.

4. The tensile adhesive strength of the laminate is 1.2 to 13 N / mm ２ The electrical steel sheet laminate according to any one of claims 1 to 3, characterized in that

5. A method for manufacturing the electromagnetic steel sheet laminate according to claim 1, 70 to 95% by weight of epoxy resin in solid content, and SiO ２ , TiO ２ a coating composition containing 5 to 30 wt % of inorganic nanoparticles of one or more of ZnO and ZnO is applied to a steel sheet, and the coating composition is cured by heat treatment; and a polymer adhesive layer is formed on the electrical steel sheet by adjusting the pressure of the roll coater and the steel sheet to 50 to 1500 kgf during application of the coating composition; laminating the magnetic steel sheets on which the polymer adhesive layer is formed; 4. The method for manufacturing an electrical steel sheet laminate, wherein the polymer adhesive layer has a coating thickness of 1.8 to 5.4 μm.

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