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

Abstract

An adhesive coating composition for an electrical steel sheet according to one embodiment of the present invention comprises a mixed resin of a urethane resin and an epoxy resin, the urethane resin comprising repeating units represented by Chemical Formula 1 and Chemical Formula 2.

Description

Technical Field

[0001] One embodiment of the present invention relates to an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same. Specifically, one embodiment of the present invention relates to an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same, which are used to form a fusion layer that can bond (connect) electrical steel sheets without using traditional connection methods such as welding, clamping, and interlocking. More specifically, one embodiment of the present invention relates to an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same, which improve the adhesive force and noise suppression characteristics of the electrical steel sheet laminate by controlling the composition of the fusion layer formed between the electrical steel sheets. Background Art

[0002] Non-oriented electrical steel sheets, as steel sheets with uniform magnetic properties in all directions on a rolled sheet, are widely used in the cores of motors, generators, electric motors, small transformers, etc.

[0003] Electrical steel sheets can be divided into two forms. One is to perform stress relief annealing (SRA) to improve the magnetic properties after punching. The other is to omit stress relief annealing when the cost loss caused by heat treatment is greater than the magnetic property effect brought by stress relief annealing.

[0004] The insulating coating film, as a coating film applied during the finishing process of products such as the cores of motors, generators, electric motors, and small transformers, is usually required to have electrical properties that suppress the generation of eddy currents. In addition, continuous punching processability, adhesion resistance, and surface adhesion are also required. Continuous punching processability refers to the ability to suppress die wear when punching into a predetermined shape and then laminating multiple sheets to form a core. Adhesion resistance refers to the ability that the core steel sheets do not adhere to each other after the stress relief annealing process that removes the processing stress of the steel sheet and restores the magnetic properties.

[0005] In addition to these basic properties, excellent coating operability of the coating solution and solution stability that can be used for a long time after formulation are also required. For such an insulating coating film, an electrical steel sheet laminate can only be manufactured by using other connection methods such as welding, clamping, and interlocking. Summary of the Invention

[0006] (I) Technical Problems to be Solved

[0007] In one embodiment of the present invention, there is provided an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same. Specifically, in one embodiment of the present invention, there is provided an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same, which are used to form a fusion layer of electrical steel sheets that can be bonded (connected) without using traditional connection methods such as welding, clamping, and interlocking. More specifically, in one embodiment of the present invention, there is provided an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same, which improve the adhesive force between electrical steel sheets by controlling the composition of the fusion layer formed between the electrical steel sheets.

[0008] (II) Technical Solution

[0009] The electrical steel sheet adhesive coating composition according to one embodiment of the present invention includes a mixed resin of urethane resin and epoxy resin, and the urethane resin includes repeating units represented by the following Chemical Formula 1 and the following Chemical Formula 2.

[0010] [Chemical Formula 1]

[0011]

[0012] [Chemical Formula 2]

[0013]

[0014] In Chemical Formula 1 and Chemical Formula 2, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, or a halogen element. L 1 , L 2 , L 3 each represents a single bond or a divalent linking group. n represents an integer from 1 to 50.

[0015] Based on 100 parts by weight of the mixed resin, the urethane resin may include 20 to 80 parts by weight, and the epoxy resin may include 20 to 80 parts by weight.

[0016] The urethane resin may include repeating units represented by the following Chemical Formula 3 and the above Chemical Formula 2.

[0017] [Chemical Formula 3]

[0018]

[0019] In Chemical Formula 3, R 1Each independently represents hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, or a halogen element. L 1 represents a single bond or a divalent linking group.

[0020] The urethane resin can be formed by reacting a diisocyanate monomer with a polyol represented by the following Chemical Formula 4.

[0021] [Chemical Formula 4]

[0022]

[0023] In the Chemical Formula 4, L 2 , L 3 each represents a single bond or a divalent linking group. n represents an integer from 1 to 50.

[0024] The diisocyanate monomer can include an aromatic diisocyanate monomer.

[0025] The aromatic diisocyanate monomer can be a compound represented by the following Chemical Formula 5.

[0026] [Chemical Formula 5]

[0027]

[0028] In the Chemical Formula 5, R 1 to R 10 each independently is hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, a halogen element, or an isocyanate group,

[0029] at least any one of R1 to R5 is an isocyanate group,

[0030] at least any one of R6 to R10 is an isocyanate group,

[0031] except for the case where R3 and R8 are simultaneously isocyanate groups,

[0032] L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group,

[0033] n is any integer from 1 to 10.

[0034] The epoxy resin can have a number average molecular weight of 5000 to 20000 and a hydroxyl value of 2 to 20 mgKOH / g.

[0035] The electrical steel sheet adhesive coating composition according to an embodiment of the present invention may further include one or more selected from the group consisting of a coupling agent, a wetting agent, a curing agent, and a curing catalyst.

[0036] Based on 100 parts by weight of the mixed resin, the coupling agent may be included in an amount of 0.2 to 3 parts by weight.

[0037] Based on 100 parts by weight of the mixed resin, the curing agent may be included in an amount of 0.5 to 2 parts by weight.

[0038] Based on 100 parts by weight of the mixed resin, the curing catalyst may be included in an amount of 0.1 to 1 part by weight.

[0039] Based on 100 parts by weight of the mixed resin, the wetting agent may be included in an amount of 0.05 to 0.5 parts by weight.

[0040] The electrical steel sheet laminate according to an embodiment of the present invention includes: a plurality of electrical steel sheets; and a fusion layer located between the plurality of electrical steel sheets, the fusion layer including a mixed resin of a urethane resin and an epoxy resin, and the urethane resin includes repeating units represented by the following Chemical Formula 1 and the following Chemical Formula 2.

[0041] [Chemical Formula 1]

[0042]

[0043] [Chemical Formula 2]

[0044]

[0045] In Chemical Formula 1 and Chemical Formula 2, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C5 to C20 heteroaryl group, a hydroxyl group, or a halogen element. L 1 、L 2 、L 3 each represents a single bond or a divalent linking group. n represents an integer from 1 to 50.

[0046] Based on 100 parts by weight of the mixed resin, the fusion layer may include 20 to 80 parts by weight of the urethane resin and 20 to 80 parts by weight of the epoxy resin.

[0047] The 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 and then curing it to form an adhesive coating; and a step of laminating and hot-fusing a plurality of electrical steel sheets formed with the adhesive coating to form a fusion layer.

[0048] (III) Beneficial Effects

[0049] According to an embodiment of the present invention, by controlling the composition of the fusion layer formed between electrical steel sheets, the adhesion between electrical steel sheets can be improved.

[0050] According to an embodiment of the present invention, electrical steel sheets can be adhered without using traditional connection methods such as welding, clamping, and interlocking. Therefore, the noise and vibration suppression effects of the electrical steel sheet laminate are more excellent.

[0051] In addition, by using a urethane resin having a specific chemical structure, excellent adhesion is also exhibited in an automotive transmission oil environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a schematic diagram of an electrical steel sheet laminate.

[0053] Figure 2 is a cross-sectional schematic view of an electrical steel sheet laminate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The terms first, second, third, etc. are used to describe various parts, components, regions, layers, and / or segments, but these parts, components, regions, layers, and / or segments should not be limited by these terms. These terms are only used to distinguish one part, component, region, layer, and / or segment from another part, component, region, layer, and / or segment. Therefore, within the scope not departing from the present invention, the first part, component, region, layer, and / or segment described below may also be described as the second part, component, region, layer, and / or segment.

[0055] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. Unless otherwise clearly indicated to the contrary in the context, the singular forms used herein are also intended to include the plural forms. The term "comprising" used in the specification may specifically refer to a certain characteristic, field, integer, step, action, element, and / or component, but does not exclude the existence or addition of other characteristics, fields, integers, steps, actions, elements, components, and / or groups.

[0056] If a part is described as being on another part, there may be other parts directly on or between the other part. If a part is described as being directly on another part, there are no other parts therebetween.

[0057] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. For terms defined in a dictionary, they should be interpreted as having a meaning consistent with the relevant technical literature and the content disclosed herein, and should not be interpreted in an idealized or overly formal sense.

[0058] In this specification, unless otherwise defined, "substituted" means that at least one hydrogen in a compound is substituted with a C1-C30 alkyl group; a C1-C10 alkoxy group; a silyl group; an alkylsilyl group; an alkoxysilyl group; or an ethenyloxy group.

[0059] In this specification, unless otherwise defined, "hetero" means an atom selected from N, O, S, and P.

[0060] The alkyl group may be a C1-C20 alkyl group, specifically, a C1-C6 lower alkyl group, a C7-C10 middle alkyl group, or a C11-C20 higher alkyl group.

[0061] For example, a C1-C4 alkyl group means an alkyl chain having 1 to 4 carbon atoms, which represents a group selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

[0062] Typical alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0063] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention belongs can easily implement the present invention. However, the present invention can be implemented in various different ways and is not limited to the embodiments described herein.

[0064] The electrical steel sheet adhesive coating composition according to an embodiment of the present invention includes a mixed resin of an urethane resin and an epoxy resin.

[0065] Hereinafter, each component will be described.

[0066] First, the urethane resin functions to reduce the crosslinking degree of the mixed resin and improve the viscoelastic properties.

[0067] In one embodiment of the present invention, by including a urethane resin having a specific chemical structure, the coating film adhesion, peel adhesive force, or ATF resistance of the manufactured electrical steel sheet laminate can be improved. Specifically, the urethane resin includes repeating units represented by the following Chemical Formula 1 and the following Chemical Formula 2.

[0068] [Chemical Formula 1]

[0069]

[0070] [Chemical Formula 2]

[0071]

[0072] In the above Chemical Formula 1 and Chemical Formula 2, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, or a halogen element. L 1 , L 2 , L 3 each represents a single bond or a divalent linking group. n represents an integer from 1 to 50.

[0073] Chemical Formula 1 is the chemical structure of an aromatic diisocyanate used as a raw material in the synthesis process of an ethyl carbamate resin.

[0074] Due to the structure of Chemical Formula 1 and the two benzene ring structures in the aromatic diisocyanate, as a hard property, heat resistance can be improved.

[0075] In Chemical Formula 1, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, or a halogen element. In Chemical Formula 1, R 1 is connected inside the benzene ring, which means substitution at any of the six substitution positions of the benzene ring. More specifically, R 1 each independently can be hydrogen, deuterium, or a substituted or unsubstituted C1-C10 alkyl group. R 1 each independently can be hydrogen or deuterium.

[0076] In Chemical Formula 1, L 1 represents a single bond or a divalent linking group. Specifically, the divalent linking group can be one or more of a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group, -O-, -(CO)-, -S-, -N-, and -P-. More specifically, L 1 can be a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group. More specifically, L 1 can be a substituted or unsubstituted C1-C10 alkylene group.

[0077] Specifically, the repeating unit of Chemical Formula 1 can be as shown in the following Chemical Formula 3.

[0078] [Chemical Formula 3]

[0079]

[0080] In Chemical Formula 3, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C6 to C20 aryl group, a substituted or unsubstituted C5 to C20 heteroaryl group, a hydroxyl group, or a halogen element. L 1 represents a single bond or a divalent linking group.

[0081] As shown in Chemical Formula 3, the linking group L 1 and the -NCOO- group and the linking group as other repeating units do not bind to the symmetric positions of the two benzene rings, thereby further improving the film adhesion, peel adhesion, or ATF resistance characteristics of the manufactured electrical steel laminate.

[0082] In Chemical Formula 3, R 1 and L 1 are the same as described in the aforementioned Chemical Formula 1, so the repeated description is omitted.

[0083] In the urethane resin, the repeating unit of Chemical Formula 1 can be contained in an amount of 20 to 50% by weight. If the repeating unit of Chemical Formula 1 is too small, there may be a problem of a decrease in the high-temperature bonding strength of the urethane resin, while if it is too large, there may be a problem of a decrease in the hot melt adhesiveness. More specifically, in the urethane resin, the repeating unit of Chemical Formula 1 can be contained in an amount of 30 to 40% by weight. The proportion of the repeating unit of Chemical Formula 1 can be adjusted by the proportion of the aromatic diisocyanate monomer added during the production of the urethane resin.

[0084] Chemical Formula 2 is the chemical structure of the polyol used as a raw material during the synthesis process of the urethane resin.

[0085] Due to the structure of Chemical Formula 2, multiple -COO- and -O- structures result in an increase in soft characteristics, thereby improving the hot melt adhesiveness.

[0086] In Chemical Formula 2, L 2 and L 3 each independently represents a single bond or a divalent linking group. Specifically, the divalent linking group can be one or more of a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 alkynylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C5 to C20 heteroarylene group, -O-, -(CO)-, -S-, -N-, and -P-. More specifically, L 1It may be a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group. More specifically, L 1 may be a substituted or unsubstituted C1-C10 alkylene group.

[0087] n may be an integer from 1 to 50. If n is too large, problems may occur in terms of heat resistance. More specifically, n may be from 1 to 20.

[0088] In the urethane resin, the repeating unit of Chemical Formula 2 may be contained in an amount of 50 to 80% by weight. If the repeating unit of Chemical Formula 2 is too small, problems such as a decrease in hot melt adhesiveness may occur. If the repeating unit of Chemical Formula 2 is too large, problems such as a decrease in the high-temperature bonding strength of the urethane resin may occur. More specifically, in the urethane resin, the repeating unit of Chemical Formula 2 may be contained in an amount of 60 to 70% by weight. For the proportion of the repeating unit of Chemical Formula 2, it can be adjusted by the proportion of the polyol added during the production of the urethane resin.

[0089] The urethane resin may be formed by the reaction of a diisocyanate monomer and a polyol represented by the following Chemical Formula 4.

[0090] [Chemical Formula 4]

[0091]

[0092] In the said Chemical Formula 4, L 2 and L 3 each represent a single bond or a divalent linking group. n represents an integer from 1 to 50.

[0093] Regarding the polyol of Chemical Formula 4, descriptions have already been made in the relevant description of the repeating unit of Chemical Formula 2 in the urethane resin, so the repeated description is omitted. L 2 and L 3 and n in Chemical Formula 4 are the same as those described in Chemical Formula 2.

[0094] The polyol may have a number average molecular weight of 400 to 1000 g / mol. If the molecular weight is too small, problems may occur in terms of hot melt adhesiveness. If the molecular weight is too large, problems may occur in terms of heat resistance. More specifically, the number average molecular weight of the polyol may be 500 to 800.

[0095] The aromatic diisocyanate monomer may be a compound represented by the following Chemical Formula 5.

[0096] [Chemical Formula 5]

[0097]

[0098] In the said Chemical Formula 5, R 1 to R 10 are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, a halogen element or an isocyanate group,

[0099] at least any one of R1 to R5 is an isocyanate group,

[0100] at least any one of R6 to R10 is an isocyanate group,

[0101] except for the case where R3 and R8 are simultaneously isocyanate groups,

[0102] L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group,

[0103] n is any integer from 1 to 10.

[0104] Regarding the aromatic diisocyanate of Chemical Formula 5, the relevant description of the repeating unit of Chemical Formula 1 in the urethane resin has been described, so the repeated description is omitted. R 1 to R 10 in Chemical Formula 5 is the same as the description of R1 in Chemical Formula 1, and L in Chemical Formula 5 is the same as the description of L 1 in Chemical Formula 1.

[0105] The aromatic diisocyanate monomer may be represented by the following Chemical Formula 6.

[0106] [Chemical Formula 6]

[0107]

[0108] In the said Chemical Formula 2, L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group.

[0109] More specifically, L may be a substituted or unsubstituted C1-C10 alkylene group. More specifically, L may be a methylene group. The aromatic diisocyanate monomer may be methylene diphenyl diisocyanate.

[0110] Based on 100 parts by weight of the mixed resin, the urethane resin may be contained in an amount of 20 to 80 parts by weight. If the content of the urethane resin is too small, the vibration damping effect may deteriorate due to the low viscoelastic properties of the mixed resin layer. If the content of the urethane resin is too large, the high-temperature adhesive strength may deteriorate due to the low crosslinking degree of the mixed resin layer. More specifically, based on 100 parts by weight of the mixed resin, the urethane resin may be contained in an amount of 30 to 70 parts by weight.

[0111] In one embodiment of the present invention, an epoxy resin is contained together with the urethane resin. The epoxy resin serves to improve the high-temperature adhesive strength by increasing the crosslinking degree.

[0112] The epoxy resin is not particularly limited, but may include one or more of bisphenol A type epoxy resin, bisphenol E type epoxy resin, cycloaliphatic type epoxy resin, and aliphatic polyglycidyl ester type epoxy resin.

[0113] The epoxy resin may have a number average molecular weight of 1,000 to 20,000 and a hydroxyl value of 2 to 20 mgKOH / g. An epoxy resin having an appropriate molecular weight and hydroxyl value is advantageous in terms of hot melt adhesiveness and heat resistance. More specifically, it may have a number average molecular weight of 5,000 to 15,000 and a hydroxyl value of 5 to 15 mgKOH / g.

[0114] The electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include one or more selected from the group consisting of a coupling agent, a wetting agent, a curing agent, and a curing catalyst.

[0115] The electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include a coupling agent to enhance the interfacial adhesive strength between the electrical steel sheet 10 and the fusion layer 20. As the coupling agent, a silane coupling agent may be included, and more specifically, one or more of an epoxy-based silane coupling agent and an amino-based silane coupling agent may be included. More specifically, it may be 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane.

[0116] When further including a coupling agent, based on 100 parts by weight of the mixed resin, it may be contained in an amount of 0.2 to 3 parts by weight. If the content of the coupling agent is too small, the effect of enhancing the interfacial adhesive strength between the electrical steel sheet and the fusion layer may not be obtained sufficiently. If the content of the coupling agent is too large, precipitates may be generated in the adhesive coating composition due to the reaction between the coupling agents. Specifically, it may be contained in an amount of 0.2 to 1 part by weight.

[0117] The electrical steel sheet bonding coating composition according to an embodiment of the present invention may further include a silicone wetting agent in the bonding coating composition to enhance the interfacial adhesion between the electrical steel sheet 10 and the fusion layer 20. As the silicone wetting additive, for example, it may be polyether-modified polydimethylsiloxane. The wetting agent may be added to the bonding composition for electrical steel sheets to enhance the interfacial adhesion between the electrical steel sheet and the fusion layer.

[0118] In the electrical steel sheet bonding coating composition according to an embodiment of the present invention, based on 100 parts by weight of the mixed resin, the wetting agent may be included in an amount of 0.05 parts by weight to 0.5 parts by weight. If the content of the wetting agent is too much, there may be a problem of coating defects caused by excessive bubbles in the coating liquid, while if the content of the wetting agent is too little, there may be a problem of a decrease in the wettability of the coating, resulting in defects on the coating surface. Specifically, it may be included in an amount of 0.05 parts by weight to 0.15 parts by weight.

[0119] The electrical steel sheet bonding coating composition according to an embodiment of the present invention may further include a curing agent to adjust the reactivity of the bonding coating surface. As the curing agent, it may include aliphatic amines, aromatic amines, amino amines, or imidazoles. More specifically, it may include dicyandiamide-based curing agents.

[0120] In the electrical steel sheet bonding coating composition according to an embodiment of the present invention, based on 100 parts by weight of the mixed resin, the curing agent may be included in an amount of 1 part by weight to 10 parts by weight. The curing agent serves to adjust the reactivity of the bonding coating surface. If the content of the curing agent is too little, there may be a problem of stickiness on the surface of the fusion layer due to a decrease in the curing reaction of the fusion layer. On the other hand, if too much curing agent is added, the connection force after low-temperature fusion may deteriorate. Specifically, it may be included in an amount of 1 part by weight to 5 parts by weight.

[0121] The electrical steel sheet bonding coating composition according to an embodiment of the present invention may further include a curing catalyst to improve the sticky defects caused by uncuring due to the rapid curing reaction during coil coating. As the curing catalyst, it may include imidazole-based curing catalysts.

[0122] In the electrical steel sheet bonding coating composition according to an embodiment of the present invention, based on 100 parts by weight of the mixed resin, the curing catalyst may be included in an amount of 0.1 part by weight to 5 parts by weight. If the content of the curing catalyst is too much, there may be a problem of deterioration of the connection force after fusion due to excessive curing reaction, while if the content of the curing catalyst is too little, there may be a problem of stickiness on the surface of the fusion layer due to uncuring. Specifically, it may be included in an amount of 0.5 part by weight to 3 parts by weight.

[0123] In addition to the foregoing components, the adhesive coating composition may contain a solvent to facilitate coating and to uniformly disperse the components. As the solvent, water, ethanol, etc. may be included. With respect to 100 parts by weight of the mixed resin, the solvent may contain 200 to 2000 parts by weight.

[0124] An electrical steel sheet laminate is provided in one embodiment of the present invention.

[0125] The electrical steel sheet laminate according to one embodiment of the present invention includes: a plurality of electrical steel sheets; and a fusion layer located between the plurality of electrical steel sheets. Figure 1 A schematic diagram showing an electrical steel sheet laminate according to one embodiment of the present invention is shown. As Figure 1 shown, it has a form in which a plurality of electrical steel sheets are laminated.

[0126] Figure 2 A cross-sectional schematic diagram showing an electrical steel sheet laminate according to one embodiment of the present invention is shown. As Figure 2 shown, the electrical steel sheet laminate 100 according to one embodiment of the present invention includes: a plurality of electrical steel sheets 10; and a fusion layer located between the plurality of electrical steel sheets 20.

[0127] The electrical steel sheet laminate according to one embodiment of the present invention may be a laminate in which, without using conventional methods such as welding, clamping, interlocking, etc., only the foregoing adhesive coating composition is used to form a fusion layer, thereby thermally fusing different electrical steel sheets.

[0128] At this time, the electrical steel sheet laminate has excellent properties of high-temperature adhesiveness and high-temperature oil resistance after thermal fusion.

[0129] Hereinafter, each component will be described in detail.

[0130] The electrical steel sheet 10 may be generally used non-oriented electrical steel sheet or oriented electrical steel sheet without limitation. In one embodiment of the present invention, since the main technical feature is to manufacture the electrical steel sheet laminate 100 by forming a fusion layer 20 between a plurality of electrical steel sheets 10, a detailed description of the electrical steel sheet 10 is omitted. More specifically, the electrical steel sheet 10 may be a non-oriented electrical steel sheet.

[0131] The fusion layer 20 is formed between a plurality of electrical steel sheets 10, and has a very strong adhesive force, and is sufficient to bond a plurality of electrical steel sheets 10 without using conventional connection methods such as welding, clamping, interlocking, etc.

[0132] For the fusion layer 20, after the adhesive coating composition is coated on the surface and cured to form an adhesive coating, it is then laminated and thermally fused to form the fusion layer 20. When a plurality of electrical steel sheets 10 having an adhesive coating formed thereon are laminated and thermally fused, the resin components in the adhesive coating are thermally fused to form a fusion layer.

[0133] In one embodiment of the present invention, the fusion layer 20 comprises a mixed resin of urethane resin and epoxy resin. As for the urethane resin, epoxy resin, and their mixed resin, they have been described in detail in the description of the adhesive coating composition, so the repeated description is omitted. During the formation of the fusion layer, the chemical structure, ratio, etc. of the urethane resin and epoxy resin remain unchanged. In addition, the coupling agent, curing agent, curing catalyst, and wetting additive also remain, and their content ranges can be the same as those of the adhesive coating composition. As for the coupling agent, curing agent, curing catalyst, and wetting additive, they have been described in detail in the description of the adhesive coating composition, so the repeated description is omitted.

[0134] Based on 100 parts by weight of the mixed resin, the fusion layer 20 may contain 20 to 80 parts by weight of urethane resin and 20 to 80 parts by weight of epoxy resin.

[0135] In addition, the fusion layer 20 may further contain 0.2 to 3 parts by weight of a coupling agent, 0.05 to 0.5 parts by weight of a wetting agent, 0.5 to 2 parts by weight of a curing agent, and 0.1 to 1 part by weight of a curing catalyst.

[0136] The thickness of the fusion layer 20 may be 1 μm to 8 μm. If the thickness of the fusion layer is too thin, the adhesive force will rapidly decrease, while if it is too thick, problems will occur due to defects caused by stickiness after coating and winding. More specifically, the thickness of the fusion layer 20 may be 1 μm to 3 μm.

[0137] In one embodiment of the present invention, the electrical steel sheet laminate improves the coating adhesion, peel adhesive force, or ATF resistance characteristics. If the drive motor is used in an automobile, a lot of heat is generated during high-speed and long-time rotation, and ATF (automatic transmission fluid) needs to be used for cooling. Therefore, in order to ensure the bonding reliability during long-term use, it is very important to maintain the adhesive force of the laminated coil in a state of being immersed in high-temperature ATF.

[0138] The manufacturing method of the electrical steel sheet laminate according to one embodiment of the present invention includes: a step of applying the adhesive coating composition to one or both sides of the electrical steel sheet and curing it to form an adhesive coating; and a step of laminating and thermally fusing a plurality of electrical steel sheets formed with the adhesive coating to form a fusion layer.

[0139] Hereinafter, each step will be described in detail.

[0140] First, prepare the adhesive coating composition. As for the adhesive coating composition, as described above, the repeated description is omitted.

[0141] Next, the adhesive coating composition is applied to the surface of the electrical steel sheet and then cured to form an adhesive coating. For this step, in order to cure the adhesive coating composition, it can be carried out at a temperature of 150 to 250 °C.

[0142] A plurality of electrical steel sheets formed with the adhesive coating are laminated and heat-fused to form a fused layer 20. Through the heat-fusion step, the polymer components in the adhesive coating are heat-fused to form the fused layer.

[0143] For the heat-fusion step, heat-fusion can be carried out at a temperature of 150 to 250 °C, a pressure of 0.05 to 5.0 Mpa, and a pressing condition of 0.1 to 120 minutes. For these conditions, they can be satisfied individually or two or more conditions can be satisfied simultaneously. Thus, by adjusting the temperature, pressure, and time conditions in the heat-fusion step, heat-fusion can be carried out tightly without gaps or organic phases between the electrical steel sheets.

[0144] The heat-fusion step includes a heating step and a fusing step, and the heating rate of the heating step can be 10 °C / minute to 1000 °C / minute.

[0145] Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement the present invention. However, the present invention can be implemented in various different ways and is not limited to the following embodiments.

[0146] Experimental Example 1

[0147] As samples, non-oriented electrical steel sheets (50X50 mm, 0.35 mm t) were prepared. After the adhesive coating liquid was coated on the upper and lower sides of each of the prepared samples with a certain thickness using a bar coater and a roll coater, it was cured at 200 °C (based on the plate temperature) for 20 seconds and then slowly cooled in the air to form an adhesive coating.

[0148] As the adhesive coating liquid, a coating liquid containing 100 parts by weight of a mixed resin of polyurethane resin and epoxy resin, 0.5 part by weight of a silane coupling agent (3-glycidoxypropyltriethoxysilane), 0.1 part by weight of a silicone-based wetting agent (polyether-modified silicone), 1 part by weight of a dicyandiamide-based curing agent (adipic dihydrazide), and 0.5 part by weight of an imidazole-based curing catalyst (1,2-dimethylimidazole) was used.

[0149] For the polyurethane resin, 40% by weight of 2,4-methylene diphenyl diisocyanate monomer and 60% by weight of poly(ethylene carbonate) diol with a number average molecular weight of 425 g / mol were reacted based on the total amount of the polyurethane resin and then used. For the epoxy resin, a bisphenol A epoxy resin with a molecular weight of 10,000 and a hydroxyl value of 10 mg KOH / g was used.

[0150] The content ratio of the polyurethane resin and the epoxy resin used, and the types and content ratios of the isocyanate monomer and polyol used to manufacture the polyurethane resin are shown in Table 1 below.

[0151] MDI in Table 1 represents methylene diphenyl diisocyanate, TDI represents toluene diisocyanate, and PCD represents poly(ethylene carbonate) diol (number average molecular weight of 425 g / mol).

[0152] The electrical steel sheets coated with the adhesive coating were laminated to a height of 20 mm, then pressed with a force of 0.5 MPa and heat-fused at 160 °C for 10 minutes to manufacture an electrical steel sheet laminate. The thickness of the fused layer after heat fusion was about 3 μm. The heat-fused laminate was evaluated according to the mixing ratio of the mixed resins in the coating composition and the type of aromatic diisocyanate monomer used. Specifically, the film adhesion, peel adhesion (T-peel, N / mm), ATF resistance property, and high-temperature adhesiveness were evaluated and shown in Table 1 below.

[0153] The measurement methods for each property are as follows:

[0154] Film adhesion measurement method: A specimen for measuring film adhesion was prepared according to ISO1519 standard. The coated specimen was made into a 30×300 mm sample, and after bending 180° around a steel cylinder with a diameter of 10 mm, a tape was pasted on this part, and then it was visually observed whether the coating peeled off. If peeling occurred, it was evaluated as non-conforming (NG), and if no peeling occurred, it was judged as conforming (OK).

[0155] Peel adhesion (T-peel, N / mm): A specimen for the peel method (T-Peel off) measurement was prepared according to ISO11339 standard. Two 25×200 mm specimens were bonded to form an area of 25×150 mm 2After that, the unbonded part is bent by 90° to fabricate a T-shaped tensile specimen. The specimen fabricated by the peel-off method (T-Peeloff) is fixed to the upper / lower jig with a certain force and then stretched at a certain speed, and the measurement is performed using a device for measuring the tensile force of the laminated specimen. At this time, in the case of the shear method, the measured value is the point at which the interface with the minimum adhesive force in the interface of the laminated specimen peels off. The temperature of the specimen is maintained at 60 °C by a heating device, and then the adhesive force is measured.

[0156] Method for evaluating ATF resistance characteristics: The fabricated laminated coil is immersed in ATF (SP4M-1) at a temperature of 160 °C for 1000 hours, and then the shear adhesive force is tested. The shear adhesive force for measuring the ATF resistance characteristics is measured by the shear method (Shear Strength). Specimens for shear method measurement are fabricated according to ISO4587 specifications. Two specimens of 25×100 mm are bonded into an area of 12.5×25 mm 2 , and heat-sealed under the above conditions to fabricate a shear method specimen. The specimen fabricated by the shear method is fixed to the upper / lower jig with a certain force and then stretched at a certain speed, and the measurement is performed using a device for measuring the tensile force of the laminated sample. At this time, in the case of the shear method, the measured value is the point at which the interface with the minimum adhesive force in the interface of the laminated specimen peels off.

[0157] Evaluation of high-temperature adhesive force: The shear adhesive force for measuring the high-temperature adhesive force is measured by the shear method (Shear Strength). Specimens for shear method measurement are fabricated according to ISO4587 specifications. Two specimens of 25×100 mm are bonded into an area of 12.5×25 mm using a coating agent 2 , and heat-sealed under the above conditions to fabricate a shear method specimen. After setting a high-temperature ambient temperature in a tensile machine equipped with a heating furnace, the specimen fabricated by the shear method is fixed to the upper / lower jig with a certain force and then stretched at a certain speed, and the measurement is performed using a device for measuring the tensile force of the laminated sample. At this time, in the case of the shear method, the measured value is the point at which the interface with the minimum adhesive force in the interface of the laminated specimen peels off. The temperature of the specimen is maintained at 180 °C by a heating device, and then the adhesive force is measured.

[0158] [Table 1]

[0159] [[ID=***]]

[0160] As shown in Table 1, similar to Examples 1 to 3, when the polyurethane resin and the epoxy resin are mixed at an appropriate content ratio and 2,4'-MDI (2,4-methylenediphenyl diisocyanate) is used as the aromatic diisocyanate monomer, excellent properties are exhibited in terms of film adhesion, peel adhesion, ATF resistance, and high-temperature adhesion.

[0161] Comparative Example 1 is a case where only the urethane resin is used without mixing the epoxy resin. In this case, the peel adhesion is excellent, but the high-temperature adhesion and ATF resistance values are less than 1 MPa, and it can be confirmed that the high-temperature adhesion and ATF resistance are poor.

[0162] Comparative Example 2 is a case where only the epoxy resin is used without mixing the urethane resin. In this case, the high-temperature adhesion and ATF resistance are excellent, but the peel adhesion value is less than 0.5, and it can be confirmed that the adhesion is poor.

[0163] Comparative Examples 3 to 11 are cases where the aromatic diisocyanate monomer in Examples 1 to 3 is changed to a compound other than 4'-MDI (2,4-methylenediphenyl diisocyanate) to produce an adhesive coating.

[0164] For Comparative Examples 3, 6, and 9 where 2,4'-TDI (2,4-toluene diisocyanate) is used as the aromatic diisocyanate, the film adhesion, ATF resistance, and high-temperature adhesion are good, but it can be confirmed that the peel adhesion is worse than that of the examples.

[0165] For Comparative Examples 4, 7, and 10 where 2,2'-MDI (2,2-methylenediphenyl diisocyanate) is used as the aromatic diisocyanate, the film adhesion, ATF resistance, and high-temperature adhesion are also good, but it can be confirmed that the peel adhesion is worse than that of the examples.

[0166] For Comparative Examples 5, 8, and 11 where 4,4'-MDI (4,4-methylenediphenyl diisocyanate) is used as the aromatic diisocyanate, the film adhesion and high-temperature adhesion are good, but it can be confirmed that the peel adhesion and ATF resistance are worse than those of the examples.

[0167] Comparative Example 12 is an example where polypropylene glycol is used as the polyol compound. The film adhesion, peel adhesion, and ATF resistance are good, but it can be confirmed that the high-temperature adhesion is poor.

[0168] The present invention can be implemented in various different ways and is not limited to the examples. Those of ordinary skill in the technical field to which the present invention pertains can understand that the present invention can be implemented in other specific ways without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above examples are exemplary in all respects and not restrictive.

[0169] Description of Reference Numerals

[0170] 100: Electrical steel sheet laminate 10: Electrical steel sheet

[0171] 20: Fusion layer.

Claims

1. An electrical steel sheet adhesive coating composition, wherein, the composition contains a mixed resin of an urethane resin and an epoxy resin, the urethane resin contains repeating units represented by the following Chemical Formula 1 and the following Chemical Formula 2, [Chemical Formula 1] [Chemical Formula 2] In the Chemical Formula 1 and Chemical Formula 2, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, or a halogen element, L 1 , L 2 , L 3 each represents a single bond or a divalent linking group, and n represents an integer from 1 to 50.

2. The electrical steel sheet adhesive coating composition according to claim 1, wherein, based on 100 parts by weight of the mixed resin, the urethane resin contains 20 to 80 parts by weight, and the epoxy resin contains 20 to 80 parts by weight.

3. The electrical steel sheet adhesive coating composition according to claim 1, wherein, the urethane resin contains repeating units represented by the following Chemical Formula 3 and the Chemical Formula 2, [Chemical Formula 3] In the chemical formula 3, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group or a halogen element, and L 1 represents a single bond or a divalent linking group.

4. The electrical steel sheet adhesive coating composition according to claim 1, wherein, the urethane resin is formed by the reaction of a diisocyanate monomer and a polyol represented by the following Chemical Formula 4, [Chemical Formula 4] In Chemical Formula 4, L 2 and L 3 each represent a single bond or a divalent linking group, and n represents an integer from 1 to 50.

5. The electrical steel sheet adhesive coating composition according to claim 4, wherein, the diisocyanate monomer contains an aromatic diisocyanate monomer.

6. The electrical steel sheet adhesive coating composition according to claim 5, wherein, the aromatic diisocyanate monomer is a compound represented by the following Chemical Formula 5, [Chemical Formula 5] In the chemical formula 5, R 1 to R 10 are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, a halogen element, or an isocyanate group, at least any one of R1 to R5 is an isocyanate group, at least any one of R6 to R10 is an isocyanate group, except for the case where R3 and R8 are simultaneously isocyanate groups, L is a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 alkynylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C5 to C20 heteroarylene group, n is any integer from 1 to 10.

7. The electrical steel sheet adhesive coating composition according to claim 1, wherein, the epoxy resin has a number average molecular weight of 5000 to 20000 and a hydroxyl value of 2 to 20 mgKOH / g.

8. The electrical steel sheet adhesive coating composition according to claim 1, wherein, the composition further contains one or more selected from the group consisting of a coupling agent, a wetting agent, a curing agent, and a curing catalyst.

9. The electrical steel sheet adhesive coating composition according to claim 8, wherein, based on 100 parts by weight of the mixed resin, the coupling agent contains 0.2 to 3 parts by weight.

10. The electrical steel sheet adhesive coating composition according to claim 8, wherein, based on 100 parts by weight of the mixed resin, the curing agent contains 0.5 to 2 parts by weight.

11. The electrical steel sheet adhesive coating composition according to claim 8, wherein, [[ID=3 ​ ​ ​ ​ ​ The fusion layer contains a mixed resin of an ethyl carbamate resin and an epoxy resin, The ethyl carbamate resin contains repeating units represented by the following Chemical Formula 1 and the following Chemical Formula 2, [Chemical Formula 1] [Chemical Formula 2] In Chemical Formula 1 and Chemical Formula 2, R 1 each independently represents hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, a hydroxyl group, or a halogen element, L 1 , L 2 , L 3 each represents a single bond or a divalent linking group, and n represents an integer from 1 to 50.

14. The electrical steel sheet laminate according to claim 13, wherein, Based on 100 parts by weight of the mixed resin, the fusion layer contains 20 to 80 parts by weight of the ethyl carbamate resin and 20 to 80 parts by weight of the epoxy resin.

15. A method for manufacturing an electrical steel sheet laminate, comprising: A step of applying the adhesive coating composition according to claim 1 to one or both sides of an electrical steel sheet and then curing it to form an adhesive coating; and A step of laminating a plurality of electrical steel sheets having the adhesive coating formed thereon and thermally fusing them to form a fusion layer.

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