Adhesive coating composition for electrical steel sheets, electrical steel sheet laminate and method for producing same

Abstract

An object of the present invention is to provide an adhesive coating composition for magnetic steel sheets, an electromagnetic steel sheet laminate, and a method for producing the same, which improve the adhesive strength between magnetic steel sheets by controlling the components of the adhesive layer formed between magnetic steel sheets. [Solution] The present invention relates to an adhesive coating composition for magnetic steel sheets, which comprises a mixed resin of polyurethane resin and epoxy resin, the mixed resin containing 55 to 98 parts by weight of the polyurethane resin and 2 to 45 parts by weight of the epoxy resin, based on 100 parts by weight of the mixed resin, and the polyurethane resin is formed by reacting an aromatic diisocyanate monomer and a polyol, and to an magnetic steel sheet laminate and a manufacturing method thereof using the same.

Description

[Technical field]

[0001] The present invention relates to an adhesive coating composition for magnetic steel sheets, an electromagnetic steel sheet laminate, and a manufacturing method thereof. More specifically, the present invention relates to an adhesive coating composition for magnetic steel sheets, an electromagnetic steel sheet laminate, and a manufacturing method thereof, which form an adhesive layer that can bond (fasten) magnetic steel sheets without using existing fastening methods such as welding, clamping, interlocking, etc. Specifically, the present invention relates to an adhesive coating composition for magnetic steel sheets, an electromagnetic steel sheet laminate, and a manufacturing method thereof, which improve the adhesive strength and noise suppression properties of the magnetic steel sheet laminate by controlling the components of the adhesive layer formed between the magnetic steel sheets. [Background technology]

[0002] Non-oriented electrical steel sheet is a steel sheet with uniform magnetic properties in all directions on the rolled sheet, and is widely used in motors, generator cores, electric motors, small transformers, etc. Electrical steel sheets can be divided into two types: those that require stress relief annealing (SRA) to improve their magnetic properties after punching, and those that do not require stress relief annealing when the cost loss due to heat treatment is greater than the magnetic property benefits of stress relief annealing.

[0003] Insulating coatings are applied in the finishing manufacturing process of laminates such as the iron cores of motors and generators, electric motors, and small transformers, and are generally required to have electrical properties that suppress the generation of eddy currents. In addition, they are required to have continuous punching workability, adhesion resistance, and surface adhesion. Continuous punching workability refers to the ability to suppress wear on the mold when multiple sheets are laminated to make an iron core after punching into a specified shape. Adhesion resistance refers to the ability to prevent adhesion between the steel sheets of the iron core 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 have excellent application workability and solution stability that allows it to be used for a long time after mixing. Such insulating coatings can only be manufactured into 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]

[0004] An object of the present invention is to provide an electromagnetic steel sheet laminate having a fusion layer formed thereon that can bond (fasten) electromagnetic steel sheets without using existing fastening methods such as welding, clamping, interlocking, etc. Specifically, the present invention is to provide an electromagnetic steel sheet adhesive coating composition, an electromagnetic steel sheet laminate, and a manufacturing method thereof that improve the adhesive strength between the electromagnetic steel sheets by controlling the components of the fusion layer formed between the electromagnetic steel sheets. [Means for solving the problem]

[0005] The electrical steel sheet adhesive coating composition of the present invention comprises a mixed resin of a polyurethane resin and an epoxy resin, the mixed resin comprising 55 to 98 parts by weight of a polyurethane resin and 2 to 45 parts by weight of an epoxy resin based on 100 parts by weight of the mixed resin, and the polyurethane resin is formed by reacting an aromatic diisocyanate monomer represented by the following chemical formula 1 with a polyol.

[0006] [ka]

[0007] In the above chemical formula 1, R 1 ~R 10 are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms, or an isocyanate group; R 1 ~R 5 One of the groups is an isocyanate group, and R6 ~R 10 One of the groups is an isocyanate group, and R 3 and R 8 and the case where are simultaneously an isocyanate group are excluded, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms, and n is any one of integers from 1 to 10.

[0008] In chemical formula 1, R 1 ~R 5 One of the groups is an isocyanate, and R 6 ~R 10 One of the groups is an isocyanate, and R 3 and R 8 isocyanate at the same time, R 1 and R 10 is simultaneously an isocyanate.

[0009] In chemical formula 1, R 1 ~R 5 One of the groups is an isocyanate, and R 6 ~R 10 One of the groups is an isocyanate, and R 1 ~R 5 Any one of the following and R 6 ~R 10 It is further excluded that any one of them is symmetrical about L and simultaneously an isocyanate.

[0010] The aromatic diisocyanate monomer represented by Chemical Formula 1 is represented by Chemical Formula 2 below.

[0011] [ka]

[0012] In the above chemical formula 2, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms.

[0013] The polyol is a compound represented by the following chemical formula 3.

[0014] [ka]

[0015] In the above chemical formula 3, R' is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms.

[0016] The polyurethane resin contains 30 to 50% by weight of an aromatic diisocyanate monomer and 50 to 70% by weight of a polyol.

[0017] The epoxy resin has a molecular weight of 5,000 to 20,000 and a hydroxyl value of 2 to 20 mgKOH / g.

[0018] The electrical steel sheet adhesive coating composition of the present invention further comprises one or more members selected from the group consisting of coupling agents, wetting agents, curing agents, and curing catalysts.

[0019] The coupling agent is contained in an amount of 0.2 to 3 parts by weight based on 100 parts by weight of the mixed resin.

[0020] The hardener is contained in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the mixed resin.

[0021] The curing catalyst is contained in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the mixed resin.

[0022] The wetting agent is included in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the mixed resin.

[0023] The electromagnetic steel sheet laminate of the present invention comprises a plurality of electromagnetic steel sheets, and a bonding layer located between the plurality of electromagnetic steel sheets, the bonding layer comprising a mixed resin of polyurethane resin and epoxy resin, the mixed resin comprising 55 to 98 parts by weight of polyurethane resin and 2 to 45 parts by weight of epoxy resin based on 100 parts by weight of the mixed resin, the polyurethane resin being formed by reacting an aromatic diisocyanate monomer represented by the following chemical formula 1 with a polyol.

[0024] [ka]

[0025] In the above chemical formula 1, R 1 ~R 10 are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms, or an isocyanate group; R 1 ~R 5 One of the groups is an isocyanate group, and R 6 ~R 10 One of the groups is an isocyanate group, and R 3 and R 8 and the case where are simultaneously an isocyanate group are excluded, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms, and n is any one of integers from 1 to 10.

[0026] The method for producing an electromagnetic steel sheet laminate of the present invention includes the steps of applying an adhesive coating composition to one or both sides of an electromagnetic steel sheet, followed by curing the composition to form an adhesive coating layer, and stacking a plurality of electromagnetic steel sheets with the adhesive coating layers formed thereon, and heat fusing the stacked sheets to form a fusion layer. The adhesive coating composition includes a mixed resin of a polyurethane resin and an epoxy resin, the mixed resin including 55 to 98 parts by weight of a polyurethane resin and 2 to 45 parts by weight of an epoxy resin, based on 100 parts by weight of the mixed resin. The polyurethane resin is formed by reacting an aromatic diisocyanate monomer represented by the following chemical formula 1 with a polyol.

[0027] [ka]

[0028] In the above chemical formula 1, R 1 ~R 10 are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms, or an isocyanate group; R 1 ~R 5 One of the groups is an isocyanate group, and R 6 ~R 10 One of the groups is an isocyanate group, and R 3 and R 8 and the case where are simultaneously an isocyanate group are excluded, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms, and n is any one of integers from 1 to 10. Effect of the Invention

[0029] According to the present invention, the components of the adhesive layer formed between the magnetic steel sheets can be controlled to improve the adhesive strength between the magnetic steel sheets. According to the present invention, the electromagnetic steel sheets can be bonded without using existing fastening methods such as welding, clamping, interlocking, etc., and the noise and vibration suppression effect of the electromagnetic steel sheet laminate is more excellent. [Brief description of the drawings]

[0030] [Figure 1] FIG. 2 is a schematic diagram of an electromagnetic steel sheet laminate. [Diagram 2] FIG. 2 is a schematic diagram of a cross section of an electrical steel sheet laminate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Thus, a first part, component, region, layer, or section described below can be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention. The terminology used herein is for the purpose of referring to particular embodiments only and is not intended to limit the present invention. As used herein, the singular form includes the plural form unless the phrase clearly indicates otherwise. As used in the specification, the meaning of "comprising" embodies the specified features, regions, integers, steps, operations, elements, and / or components and does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components. When an element is referred to as being "on" or "on" another element, it means that it is directly on or above the other element, or there may be other elements between them. In contrast, when an element is referred to as being "directly on" another element, there are no other elements between them. Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted to have a meaning consistent with the relevant technical literature and the currently disclosed content, and are not interpreted in an ideal or very formal sense unless otherwise defined.

[0032] Unless otherwise defined, in this specification, "substituted" means that at least one hydrogen in a compound is substituted with an alkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a silane group, an alkylsilane group, an alkoxysilane group, or an ethyleneoxyl group.

[0033] By "hetero" herein, unless otherwise defined, is meant an atom selected from the group consisting of N, O, S, and P.

[0034] The alkyl group may be an alkyl group having 1 to 20 carbon atoms, specifically, a lower alkyl group having 1 to 6 carbon atoms, a medium alkyl group having 7 to 10 carbon atoms, or a higher alkyl group having 11 to 20 carbon atoms.

[0035] For example, a C1-4 alkyl group means that there are from 1 to 4 carbon atoms in the alkyl chain and is selected from the group consisting of methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and t-butyl. Typical alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like.

[0036] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention;

[0037] The magnetic steel sheet adhesive coating composition according to one embodiment of the present invention comprises a mixed resin of a polyurethane resin and an epoxy resin, the mixed resin comprising 55 to 98 parts by weight of a polyurethane resin and 2 to 45 parts by weight of an epoxy resin based on 100 parts by weight of the mixed resin, and the polyurethane resin may be formed by reacting an aromatic diisocyanate monomer represented by the following Chemical Formula 1 with a polyol.

[0038] [ka]

[0039] In chemical formula 1, R 1 ~R 10 are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms, or an isocyanate group; R 1 ~R 5 One of the groups is an isocyanate group, and R 6 ~R 10 One of the groups is an isocyanate group, and R 3 and R 8 and the case where are simultaneously an isocyanate group are excluded, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms, and n is any one of integers from 1 to 10.

[0040] In one embodiment of the present invention, the mixed resin may include 55 to 98 parts by weight of polyurethane resin and 2 to 45 parts by weight of epoxy resin based on 100 parts by weight of the mixed resin. If the polyurethane resin is included too much, the high temperature adhesive strength may be inferior due to the low crosslinking degree of the mixed resin layer, and if the polyurethane resin is included too little, the vibration suppression effect may be inferior due to the low viscoelasticity characteristics of the mixed resin layer. If the epoxy resin is included too much, the vibration suppression effect may be inferior due to the decrease in viscoelasticity characteristics due to the high crosslinking degree of the mixed resin layer, and if the epoxy resin is included too little, the high temperature adhesive strength may be inferior due to the low crosslinking degree of the mixed resin layer.

[0041] In chemical formula 1, R 1 ~R 5 One of the groups is an isocyanate, and R 6 ~R 10 One of the groups is an isocyanate, and R 3 and R 8 isocyanate at the same time, R 1 and R 10 may further be excluded where simultaneously is an isocyanate.

[0042] In chemical formula 1, R 1 ~R 5 One of the groups is an isocyanate, and R 6 ~R 10 One of the groups is an isocyanate, and R 1 ~R 5 Any one of the following and R 6 ~R 10 It may be further excluded that any one of them is simultaneously an isocyanate symmetrically with respect to L.

[0043] In Chemical Formula 1, when isocyanate is bonded at positions symmetrical with respect to L, the coating adhesion, peel adhesion, or ATF resistance of the produced electrical steel sheet laminate is inferior, and thus it cannot be used for self-bonding.

[0044] The aromatic diisocyanate monomer represented by Chemical Formula 1 may be represented by Chemical Formula 2 below.

[0045] [ka]

[0046] In Chemical Formula 2, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms.

[0047] The polyol may be a compound represented by the following formula 3.

[0048] [ka]

[0049] In Chemical Formula 3, R' is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms. Specifically, the polyol may be polypropylene glycol.

[0050] The polyol may have a number average molecular weight of 400 to 1000 g / mol.

[0051] The polyurethane resin may contain 30-50% by weight of aromatic diisocyanate monomer and 50-70% by weight of polyol. If the ratio of aromatic diisocyanate monomer is too small, the polyurethane resin may have a problem of reduced high-temperature fastening force, and if it is too large, the polyurethane resin may have a problem of reduced heat fusion properties. If the ratio of polyol is too small, the heat fusion properties may be reduced, and if the ratio of polyol is too large, the polyurethane resin may have a problem of sticky defects during long-term storage in a coiled state due to its tacky properties.

[0052] The epoxy resin may have a molecular weight of 5,000 to 20,000 and a hydroxyl value of 2 to 20 mg KOH / g.

[0053] The electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include at least one selected from the group consisting of a coupling agent, a wetting agent, a curing agent, and a curing catalyst.

[0054] The magnetic steel sheet adhesive coating composition according to an embodiment of the present invention may further include a coupling agent to strengthen the interfacial adhesion between the magnetic steel sheet 10 and the adhesive layer 20. The coupling agent may include a silane coupling agent, and more specifically, may include at least one of a vinyl-based silane coupling agent and a methacryloxy-based silane coupling agent. Examples of the vinyl-based silane coupling agent may include vinyl trimethoxy silane, vinyl triethoxy silane, etc. Methacryloxy-based silane coupling agents can include 3-methacryloxypropyl methyldimethoxysilane, 3-methacryloxpropyl trimethoxysilane, 3-methacryloxypropyl methyldiethoxysilane, and 3-methacryloxypropyl triethoxysilane.

[0055] The magnetic steel sheet adhesive coating composition according to one embodiment of the present invention may further include a silicon-based wetting agent in the adhesive coating composition to strengthen the interfacial adhesion between the magnetic steel sheet 10 and the adhesive layer 20. An example of the silicon-based wetting additive is polyether-modified polydimethylsiloxane. The wetting agent may be added to the magnetic steel sheet bonding composition to strengthen the interfacial adhesion between the magnetic steel sheet and the adhesive layer.

[0056] The magnetic steel sheet adhesive coating composition according to one embodiment of the present invention may further include a curing agent to adjust the reactivity of the adhesive coating layer surface. The curing agent may include an aliphatic amine-based, aromatic amine-based, aminoamine-based, or imidazole-based curing agent. More specifically, a dicyandiamide-based curing agent may be included.

[0057] The electrical steel sheet adhesive coating composition according to an embodiment of the present invention may further include a curing catalyst to improve sticky defects caused by uncured due to a rapid curing reaction during coil coating. The curing catalyst may include an imidazole-based curing catalyst.

[0058] The magnetic steel sheet adhesive coating composition according to one embodiment of the present invention may contain 0.2 to 3 parts by weight of the coupling agent based on 100 parts by weight of the mixed resin. Specifically, it may contain 0.2 to 1 part by weight. If the amount of the coupling agent is too small, the effect of strengthening the interfacial adhesion between the magnetic steel sheet and the adhesive layer may not be sufficiently obtained. If the amount of the coupling agent is too large, a precipitate may be generated in the adhesive coating composition due to a reaction between the coupling agents.

[0059] In the magnetic steel sheet adhesive coating composition according to one embodiment of the present invention, the curing agent may be contained in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the mixed resin. Specifically, the curing agent may be contained in an amount of 0.8 to 1.2 parts by weight. The curing agent plays a role in adjusting the reactivity of the adhesive coating layer surface. If the curing agent is contained in an excessively small amount, the curing reaction of the adhesive layer may be reduced, resulting in a problem of the adhesive layer surface becoming sticky. Conversely, if the curing agent is added in an excessively large amount, the fastening force may become inferior after low-temperature fusion.

[0060] In the magnetic steel sheet adhesive coating composition according to one embodiment of the present invention, the curing catalyst may be contained in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the mixed resin. Specifically, the curing catalyst may be contained in an amount of 0.3 to 0.8 parts by weight. If the content of the curing catalyst is too high, a problem of poor fastening force after fusion may occur due to an over-curing reaction, and if the content of the curing catalyst is too low, a problem of sticky surface of the fusion layer may occur due to insufficient curing.

[0061] In the magnetic steel sheet adhesive coating composition according to one embodiment of the present invention, the wetting agent may include 0.05 to 0.5 parts by weight based on 100 parts by weight of the mixed resin. Specifically, the wetting agent may include 0.05 to 0.15 parts by weight. If the content of the wetting agent is too high, problems such as defects in the coating layer due to excessive bubbles being generated in the coating liquid may occur, and if the content of the wetting agent is too low, problems such as defects in the coating surface due to reduced wettability of the coating layer may occur.

[0062] In addition to the above-mentioned components, the adhesive coating composition may contain a solvent to facilitate application and to disperse the components uniformly. The solvent may include water, alcohol, etc. The solvent may be included in an amount of 1 to 20 parts by weight per 100 parts by weight of the mixed resin.

[0063] In one embodiment of the present invention, an electrical steel laminate is provided. An electromagnetic steel sheet laminate according to an embodiment of the present invention includes a plurality of electromagnetic steel sheets and a fusion layer located between the plurality of electromagnetic steel sheets. Fig. 1 shows a schematic diagram of an electromagnetic steel sheet laminate according to an embodiment of the present invention. As shown in Fig. 1, the electromagnetic steel sheet laminate has a configuration in which a plurality of electromagnetic steel sheets are laminated.

[0064] A schematic cross-sectional view of an electrical steel sheet laminate according to an embodiment of the present invention is shown in Fig. 2. As shown in Fig. 2, an electrical steel sheet laminate 100 according to an embodiment of the present invention includes a plurality of electrical steel sheets 10 and a bonding layer 20 located between the plurality of electrical steel sheets.

[0065] The electrical steel sheet laminate according to one embodiment of the present invention may be a laminate in which different electrical steel sheets are heat-fused together by simply forming a fusion layer using the above-mentioned adhesive coating composition, without using existing methods such as welding, clamping, interlocking, etc.

[0066] In this case, the magnetic steel sheet laminate has excellent high-temperature adhesion and high-temperature oil resistance even after heat fusion.

[0067] Each component will be described in detail below. General non-oriented or oriented electromagnetic steel sheets can be used without any restrictions as the electromagnetic steel sheets 10. In one embodiment of the present invention, the main configuration is to form a fusion layer 20 between a plurality of electromagnetic steel sheets 10 to produce an electromagnetic steel sheet laminate 100, so a detailed description of the electromagnetic steel sheets 10 will be omitted.

[0068] The adhesive layer 20 is formed between the plurality of magnetic steel sheets 10, and has such a strong adhesive force that the plurality of magnetic steel sheets 10 can be bonded together without using existing fastening methods such as welding, clamping, or interlocking.

[0069] The fusion layer 20 is formed by coating the surface with an adhesive coating composition, curing it to form an adhesive coating layer, and stacking and heat-sealing this to form the fusion layer 20. When multiple magnetic steel sheets 10 with adhesive coating layers formed thereon are stacked and heat-sealed, the resin component in the adhesive coating layer is heat-sealed to form the fusion layer.

[0070] In one embodiment of the present invention, the adhesive layer 20 includes a mixed resin of polyurethane resin and epoxy resin. The polyurethane resin, epoxy resin, and the mixed resin thereof have been described in detail in relation to the adhesive coating composition, so a duplicated description will be omitted. The mixed resin of polyurethane resin and epoxy resin remains as it is during the adhesive layer formation process. In addition, the coupling agent, curing agent, curing catalyst, and wetting additive also remain, and the content ranges thereof may be the same as those of the adhesive coating composition. The coupling agent, curing agent, curing catalyst, and wetting additive have been described in detail in relation to the adhesive coating composition, so a duplicated description will be omitted.

[0071] Therefore, the adhesive layer may include 100 parts by weight of mixed resin, 0.5 parts by weight of silane coupling agent, 0.1 parts by weight of silicon-based wetting agent, 1 part by weight of dicyandiamide-based curing agent, and 0.5 parts by weight of imidazole-based curing catalyst. The thickness of the adhesive layer 20 may be 1 μm to 8 μm. If the thickness of the adhesive layer is too thin, the adhesive strength may be rapidly reduced, and if the thickness is too thick, defects due to stickiness may become a problem after coating and winding. More specifically, the thickness of the adhesive layer 20 may be 4 μm to 6 μm.

[0072] A method for manufacturing an electrical steel sheet laminate according to an embodiment of the present invention includes a step of applying an adhesive coating composition to one or both sides of an electrical steel sheet, followed by curing the composition to form an adhesive coating layer, and a step of stacking a plurality of electrical steel sheets with the adhesive coating layers formed thereon, and heat-fusing the stacked electrical steel sheets to form a fusion layer.

[0073] Each step will be explained in detail below. First, the adhesive coating composition is prepared. The adhesive coating composition has been described above, so a duplicate description will be omitted. Next, the adhesive coating composition is coated on the surface of the magnetic steel sheet and then cured to form an adhesive coating layer, which can be performed at a temperature range of 150 to 250°C to cure the adhesive coating composition.

[0074] A plurality of magnetic steel sheets having adhesive coating layers formed thereon are stacked and heat-sealed to form a fusion layer 20. Through the heat-sealing step, the polymer components in the adhesive coating layer are heat-sealed to form a fusion layer. The heat fusion step can be performed under conditions of a temperature of 150 to 250°C, a pressure of 0.05 to 5.0 MPa, and a pressurizing time of 0.1 to 120 minutes. Each of the conditions can be satisfied independently, or two or more conditions can be satisfied simultaneously. By adjusting the temperature, pressure, and time conditions in the heat fusion step in this manner, the electrical steel sheets can be heat fused densely without any gaps or organic phases between them. The heat-sealing step includes a temperature-raising step and a fusion step, and the temperature-raising rate in the temperature-raising step may be 10° C. / min to 1000° C. / min.

[0075] The present invention may, however, be embodied in many different forms and is not limited to the embodiments set forth herein. EXAMPLES

[0076] Experimental Example 1 Non-oriented electrical steel sheets (50 x 50 mm, 0.35 mmt) were prepared as test pieces. The adhesive coating solution was applied to the top and bottom of each test piece using a bar coater and a roll coater at a uniform thickness, cured for 20 seconds at a sheet temperature of 200°C, and then gradually cooled in air to form an adhesive coating layer.

[0077] The adhesive coating solution used contained 100 parts by weight of a mixed resin of polyurethane resin and epoxy resin, 0.5 parts by weight of a silane coupling agent, 0.1 parts by weight of a silicon-based wetting agent, 1 part by weight of a dicyandiamide-based curing agent, and 0.5 parts by weight of an imidazole-based curing catalyst. The polyurethane resin was prepared by reacting 40% by weight of 2,4-methylenediphenyl diisocyanate monomer and 60% by weight of polypropylene glycol having a water molecular weight of 425 g / mol based on the total weight of the polyurethane resin, and the epoxy resin had a molecular weight of 1,000 to 20,000 and a hydroxyl value of 2 to 20 mgKOH / g. The content ratio of the polyurethane resin and epoxy resin used, and the types and content ratios of the isocyanate monomer and polyol used in the polyurethane resin preparation are shown in Table 1 below. In addition to the polyurethane resin, the composition contains 0.5 parts by weight of a silane coupling agent, 0.1 parts by weight of a silicon-based wetting agent, 1 part by weight of a dicyandiamide-based curing agent, and 0.5 parts by weight of an imidazole-based curing catalyst, based on 100 parts by weight of the polyurethane resin.

[0078] In Table 1, MDI means methylene diphenyl diisocyanate, TDI means toluene diisocyanate, and PPG means polypropylene glycol (molecular weight 425 g / mol).

[0079] The adhesive coating layer-coated magnetic steel sheets were stacked to a height of 20 mm, and then pressed with a force of 0.5 MPa and heat-sealed at 160°C for 10 minutes to produce a magnetic steel sheet laminate. After heat-sealing, the thickness of the fused layer was approximately 6 μm. The heat-sealed laminates were evaluated according to the mixing ratio of the mixed resins in the coating composition and the type of aromatic diisocyanate monomer used. Specifically, the coating adhesion, peel adhesion strength (T-peel, N / mm), ATF resistance, damping ratio, and high temperature adhesion were evaluated and are shown in Table 1 below.

[0080] The methods for measuring each characteristic are as follows.

[0081] Coating adhesion test method: The coating adhesion test specimen was created based on ISO 1519. The coated specimen was created as a sample of 30 x 300 mm and bent 180 degrees into a 10 mm diameter iron cylinder, after which tape was attached to that area and the coating layer was observed with the naked eye for peeling. If peeling occurred, it was rated as NG, and if no peeling occurred, it was rated as OK.

[0082] Peel adhesion (T-peel, N / mm): The specimen for the peel off test was made according to ISO 11339. Two 25×200 mm specimens were placed on a 25×150 mm 2 After bonding the area, the unbonded area was bent 90° to prepare a T-shaped tensile specimen.

[0083] The specimens made by the peeling method (T-Peel off) were fixed to the upper / lower jigs with a constant force, and the tensile strength of the laminated sample was measured using a device that measures the strength of the laminated sample while pulling at a constant speed. In the case of the shear method, the measured value was the point where the interface with the smallest adhesive strength among the interfaces of the laminated sample fell off. The temperature of the specimen was maintained at 60℃ using a heating device, and the adhesive strength was measured.

[0084] ATF resistance evaluation method: When a drive motor is used in an automobile, a lot of heat is generated when it rotates at high speed for a long time, and ATF (Automotive Transmission Fluid) is used to cool it. Therefore, in order to ensure adhesive reliability during long-term use, it is important that the adhesive strength of the laminated coil is maintained while it is immersed in high-temperature ATF. Therefore, ATF resistance was evaluated. The manufactured laminated coil was immersed in ATF at a temperature of 150°C for 500 hours, and then the shear adhesive strength was tested. The shear adhesive strength for measuring ATF resistance was measured using the shear strength method. The specimen standard for shear strength measurement was based on ISO 4587. Two 25 x 100 mm specimens were cut into 12.5 x 25 mm pieces. 2A shear test specimen was prepared by heat fusing under the conditions of bonding an area of ​​100 mm. The test specimen prepared by the shear method was fixed to the upper / lower jig with a certain force, and then pulled at a certain speed using a device that measures the tensile strength of the laminated sample. At this time, in the case of the shear method, the measured value was the point where the interface with the minimum adhesive strength among the interfaces of the laminated sample fell off.

[0085] Noise suppression characteristic evaluation: A ring-type motor core was manufactured to evaluate the noise characteristics generated by the motor core unit in the driving motor. A ring core with an outer diameter of 128 mm, an inner diameter of 90 mm, and a height of 45 mm was manufactured by punching and heat-sealing a product in which a coating agent was applied to a 0.27 mm non-oriented electromagnetic steel sheet. The dynamic characteristics in the axial direction of the ring core manufactured in this way were measured. In order to grasp the dynamic characteristics (natural frequency, natural mode, damping ratio) of a machine or structure, a transfer function is usually used, which is a function that applies an external force and determines the dynamic response to it. This is a function that indicates the ratio of the response to an external force (F), and when analyzing frequency as a response, it is called a frequency response function (FRF) and is the basic and most commonly used basic function for interpreting dynamic characteristics. The damping ratio was measured through this FRF characteristic analysis. The higher the damping ratio, the better the vibration absorption and the less vibration and noise are generated.

[0086] High temperature adhesive strength evaluation: Shear adhesive strength for measuring high temperature adhesive strength was measured by the shear strength method. The specimen standard for the shear strength method was made according to ISO 4587. Two 25 x 100 mm specimens were cut into 12.5 x 25 mm pieces using a coating agent. 2The area of ​​each sample was bonded and heat fused under the above conditions to prepare a shear method specimen. The specimen prepared by the shear method was set to a high ambient temperature in a tensile machine with a heating furnace, and then fixed to the upper and lower jigs with a constant force and pulled at a constant speed, and the tensile strength of the laminated sample was measured using a device that measures this. At this time, in the case of the shear method, the measured value was the point where the interface with the minimum adhesive strength among the interfaces of the laminated sample fell off. The temperature of the specimen was maintained at 160℃ using a heating device, and the adhesive strength was measured.

[0087] [Table 1]

[0088] As shown in Table 1, when the polyurethane resin and the epoxy resin were mixed in an appropriate content ratio as in Examples 1 to 3, and 2,4'-MDI (2,4-methylenediphenyl diisocyanate) was used as the aromatic diisocyanate monomer, excellent properties were exhibited in all of the coating adhesion, peel adhesion, ATF resistance, vibration absorption, and high temperature adhesion.

[0089] Comparative Example 1 is a case where only polyurethane resin was used without mixing epoxy resin. It is confirmed that the coating adhesion, peel adhesion, and vibration absorption properties are excellent, but the high temperature adhesion is inferior, showing a value of less than 1 MPa, and the ATF resistance properties are also inferior.

[0090] Comparative Example 2 is a case where only epoxy resin is used without mixing polyurethane resin. The coating adhesion, ATF resistance, and high temperature adhesion are excellent, but the peel adhesion is poor and the damping ratio is less than 0.03, indicating that the noise and vibration suppression effect is inferior.

[0091] Comparative Example 3 is a case where the polyurethane resin content is low and the epoxy resin content is high. It can be seen that the coating adhesion, ATF resistance, and high temperature adhesion are excellent, but the peel adhesion and vibration absorption are poor.

[0092] In Comparative Examples 4 to 12, the aromatic diisocyanate monomer in Examples 1 to 3 was changed to a compound other than 2,4'-MDI (2,4-methylene diphenyl diisocyanate) to prepare an adhesive coating layer.

[0093] In the case of Comparative Examples 4, 7, and 10, in which 2,4'-TDI (2,4-toluene diisocyanate) was used as the aromatic diisocyanate, it was confirmed that the coating adhesion, ATF resistance, and high temperature adhesion were good, but the peel adhesion and vibration absorption were inferior to those of the Examples.

[0094] In the cases of Comparative Examples 5, 8, and 11, in which 2,2'-MDI (2,2-methylene diphenyl diisocyanate) was used as the aromatic diisocyanate, it was confirmed that the coating adhesion, ATF resistance, and high temperature adhesion were good, but the peel adhesion and vibration absorption were inferior to those of the Examples.

[0095] In the case of Comparative Examples 6, 9, and 12, in which 4,4'-MDI (4,4-methylene diphenyl diisocyanate) was used as the aromatic diisocyanate, it was confirmed that the coating adhesion, vibration absorption, and high temperature adhesion were good, but the peel adhesion and ATF resistance were inferior to those of the Examples.

[0096] The present invention is not limited to the embodiments, and can be manufactured in various different forms, and a person having ordinary skill in the art to which the present invention pertains can 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, it should be understood that the embodiments described above are illustrative and not limiting in all respects.

Claims

1. The mixture includes a polyurethane resin and an epoxy resin. The mixed resin includes 55 to 98 parts by weight of the polyurethane resin and 2 to 45 parts by weight of the epoxy resin based on 100 parts by weight of the mixed resin, The polyurethane resin is formed by reacting an aromatic diisocyanate monomer represented by the following formula 1 with a polyol. 【Chemistry 1】 In the above chemical formula 1, R １ ~R １０ each independently represents hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms, or an isocyanate group; R １ ~R ５ any one of which is an isocyanate group; R ６ ~R １０ any one of which is an isocyanate group; R ３ and R ８ is an isocyanate group at the same time, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms; n is any one of integers from 1 to 10.

2. In the above formula 1, R １ ~R ５ Any one of R is an isocyanate; ６ ~R １０ one of which is an isocyanate; R ３ and R ８ isocyanate at the same time, R １ and R １０ The electrical steel sheet adhesive coating composition according to claim 1, further excluding the case where is simultaneously an isocyanate.

3. In the above Chemical Formula 1, R １ ~R ５ Any one of R is an isocyanate; ６ ~R １０ one of which is an isocyanate; R １ ~R ５ Any one of the following and R ６ ~R １０ 2. The adhesive coating composition for electrical steel sheets according to claim 1, further excluding the case where any one of the above is an isocyanate symmetrically about L.

4. 2. The adhesive coating composition for electrical steel sheets according to claim 1, wherein the aromatic diisocyanate monomer represented by Chemical Formula 1 is represented by Chemical Formula 2 below. 【Chemistry 2】 In the above chemical formula 2, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms.

5. 2. The adhesive coating composition for electrical steel sheets according to claim 1, wherein the polyol is a compound represented by the following formula 3: 【Chemistry 3】 In the above chemical formula 3, R' is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms.

6. 2. The adhesive coating composition for magnetic steel sheets according to claim 1, wherein the polyurethane resin contains 30 to 50% by weight of the aromatic diisocyanate monomer and 50 to 70% by weight of the polyol.

7. 2. The adhesive coating composition for electrical steel sheets according to claim 1, wherein the epoxy resin has a molecular weight of 5,000 to 20,000 and a hydroxyl value of 2 to 20 mgKOH / g.

8. 2. The electrical steel sheet adhesive coating composition according to claim 1, further comprising at least one selected from the group consisting of a coupling agent, a wetting agent, a curing agent, and a curing catalyst.

9. 9. The adhesive coating composition for electrical steel sheets according to claim 8, wherein the coupling agent is present in an amount of 0.2 to 3 parts by weight based on 100 parts by weight of the mixed resin.

10. 9. The adhesive coating composition for electrical steel sheets according to claim 8, wherein the hardener is present in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the mixed resin.

11. 9. The adhesive coating composition for electrical steel sheets according to claim 8, wherein the curing catalyst is present in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the mixed resin.

12. 9. The adhesive coating composition for electrical steel sheets according to claim 8, wherein the wetting agent is present in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the mixed resin.

13. A plurality of electrical steel sheets; and A bonding layer is disposed between the plurality of magnetic steel sheets, The fusion layer contains a mixed resin of a polyurethane resin and an epoxy resin, The mixed resin includes 55 to 98 parts by weight of the polyurethane resin and 2 to 45 parts by weight of the epoxy resin based on 100 parts by weight of the mixed resin, The polyurethane resin is formed by reacting an aromatic diisocyanate monomer represented by the following chemical formula 1 with a polyol. 【Chemistry 1】 In the above chemical formula 1, R １ ~R １０ each independently represents hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms, or an isocyanate group; R １ ~R ５ any one of which is an isocyanate group; R ６ ~R １０ any one of which is an isocyanate group; R ３ and R ８ is an isocyanate group at the same time, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms; n is any one of integers from 1 to 10.

14. applying an adhesive coating composition to one or both sides of an electrical steel sheet and curing the composition to form an adhesive coating layer; and Stacking the plurality of magnetic steel sheets having the adhesive coating layer thereon and heat-sealing them to form an adhesive layer, The adhesive coating composition comprises a mixed resin of a polyurethane resin and an epoxy resin, The mixed resin includes 55 to 98 parts by weight of the polyurethane resin and 2 to 45 parts by weight of the epoxy resin based on 100 parts by weight of the mixed resin, The polyurethane resin is formed by reacting an aromatic diisocyanate monomer represented by the following chemical formula 1 with a polyol. 【Chemistry 1】 In the above chemical formula 1, R １ ~R １０ each independently represents hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 carbon atoms, or an isocyanate group; R １ ~R ５ any one of which is an isocyanate group; R ６ ~R １０ any one of which is an isocyanate group; R ３ and R ８ is an isocyanate group at the same time, L is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms; n is any one of integers from 1 to 10.

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