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

Abstract

An adhesive coating composition for an electrical steel sheet according to an embodiment of the present invention comprises a urethane resin and an inorganic filler, wherein the urethane resin comprises repeating units represented by chemical formula 1 and chemical formula 2.

Description

Electrical steel sheet adhesive coating composition, electrical steel sheet laminate, and method of manufacturing the same

[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, wherein a fusion layer is formed to bond (fasten) electrical steel sheets without using conventional fastening methods such as welding, clamping, or 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, wherein the adhesive strength and noise suppression characteristics of the electrical steel sheet laminate are improved by controlling the components of the fusion layer formed between electrical steel sheets.

[0002] Non-oriented electrical steel is a steel sheet with uniform magnetic properties in all directions on the rolled plate, and is widely used in motors, generator cores, electric motors, and small transformers.

[0003] Electrical steel sheets can be classified into two types: one in which stress relief annealing (SRA) must be performed to improve magnetic properties after stamping, and another in which stress relief annealing is omitted if the cost loss due to heat treatment outweighs the effect on magnetic properties from stress relief annealing.

[0004] Insulating films are coatings applied during the finishing manufacturing process of laminates such as iron cores for motors and generators, electric motors, and small transformers, and typically require electrical properties that suppress the generation of eddy currents. In addition, continuous stamping processability, anti-sticking properties, and surface adhesion properties are required. Continuous stamping processability refers to the ability to suppress mold wear when multiple sheets are stamped into a predetermined shape and then laminated to form an iron core. Anti-sticking properties refer to the ability to prevent adhesion between iron core steel sheets after a stress-relief annealing process, which removes processing stress from the steel sheets and restores their magnetic properties.

[0005] In addition to these basic characteristics, excellent application workability of the coating solution and solution stability allowing for long-term use after mixing are also required. Such insulating films can be manufactured into electrical steel laminates by using separate fastening methods such as welding, clamping, and interlocking.

[0006] In one embodiment of the present invention, an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same are provided. Specifically, in one embodiment of the present invention, an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same are provided for forming a fusion layer capable of bonding (fastening) electrical steel sheets without using conventional fastening methods such as welding, clamping, or interlocking. More specifically, an electrical steel sheet adhesive coating composition, an electrical steel sheet laminate, and a method for manufacturing the same are provided by controlling the components of the fusion layer formed between electrical steel sheets to improve the adhesion between electrical steel sheets.

[0007] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention comprises a urethane resin and an inorganic filler, and the urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2.

[0008] [Chemical Formula 1]

[0009]

[0010] [Chemical Formula 2]

[0011]

[0012] (R in Chemical Formulas 1 and 2 above 1 Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.)

[0013] With respect to 100 parts by weight of the sum of the urethane resin and the inorganic filler, the urethane resin may comprise 50 to 90 parts by weight and the inorganic filler may comprise 10 to 50 parts by weight.

[0014] The urethane resin may include repeating units represented by the following chemical formula 3 and the above chemical formula 2.

[0015] [Chemical Formula 3]

[0016]

[0017] (R in the above chemical formula 3 1 Each 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. 1 represents a single bond or a divalent linker.

[0018] Urethane resin may be formed by the reaction of a diisocyanate monomer and a polyol represented by the following chemical formula 4.

[0019] [Chemical Formula 4]

[0020]

[0021] (In the above chemical formula 4, L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.)

[0022] Diisocyanate monomers may include aromatic diisocyanate monomers.

[0023] The aromatic diisocyanate monomer may be a compound represented by the following chemical formula 5.

[0024] [Chemical Formula 5]

[0025]

[0026] (R in the above chemical formula 5 1 to R 10 Each is independently 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, a halogen element, or an isocyanate group, and

[0027] R 1 to R 5 At least one of them is an isocyanate group, and

[0028] R 6 to R 10 At least one of them is an isocyanate group, and

[0029] R 3 and R 8 Cases where it is simultaneously an isocyanate group are excluded, and

[0030] 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, and

[0031] n is an integer from 1 to 10.

[0032] Inorganic fillers may include one or more of oxides, nitrides, and carbides.

[0033] The inorganic filler may include one or more of Be, Al, Si, B, and Mg.

[0034] An 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.

[0035] The coupling agent may comprise 0.2 to 3 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler.

[0036] The curing agent may comprise 0.5 to 2 parts by weight per 100 parts by weight of the total of the urethane resin and inorganic filler.

[0037] The curing catalyst may comprise 0.1 to 1 weight part per 100 weight parts of the total of the urethane resin and inorganic filler.

[0038] The wetting agent may comprise 0.05 to 0.5 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler.

[0039] An electrical steel sheet according to one embodiment of the present invention comprises an electrical steel sheet substrate; and a fusion layer located on the electrical steel sheet substrate; wherein the fusion layer comprises a urethane resin and an inorganic filler, and the urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2.

[0040] [Chemical Formula 1]

[0041]

[0042] [Chemical Formula 2]

[0043]

[0044] (R in Chemical Formulas 1 and 2 above 1 Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.)

[0045] An electrical steel sheet laminate according to one embodiment of the present invention comprises a plurality of electrical steel sheets; and a fusion layer located between the plurality of electrical steel sheets; wherein the fusion layer comprises a urethane resin and an inorganic filler, and the urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2.

[0046] [Chemical Formula 1]

[0047]

[0048] [Chemical Formula 2]

[0049]

[0050] (R in Chemical Formulas 1 and 2 above 1 Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.)

[0051] The fusion layer may comprise 50 to 90 parts by weight of urethane resin and 10 to 50 parts by weight of inorganic filler, based on a total of 100 parts by weight of urethane resin and inorganic filler.

[0052] A method for manufacturing an electrical steel sheet laminate according to one embodiment of the present invention includes the steps 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 layer; and laminating a plurality of electrical steel sheets having adhesive coating layers formed thereon and heat-fusion to form a fusion layer.

[0053] According to one embodiment of the present invention, the adhesive strength between electrical steel sheets can be improved by controlling the components of the fusion layer formed between electrical steel sheets.

[0054] According to one embodiment of the present invention, electrical steel sheets can be bonded without using conventional fastening methods such as welding, clamping, or interlocking, thereby providing a superior noise and vibration suppression effect for the electrical steel sheet laminate.

[0055] In addition, by using a urethane resin with a specific chemical structure, it offers excellent adhesion even in automotive transmission oil environments.

[0056] Figure 1 is a schematic diagram of an electrical steel sheet laminate.

[0057] FIG. 2 is a schematic diagram of a cross-section of an electrical steel sheet laminate according to one embodiment of the present invention.

[0058] 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 solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0059] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0060] When it is stated that one part is "on" or "on" another part, it may be directly on or on the other part, or another part may be involved in between. In contrast, when it is stated that one part is "directly on" another part, no other part is interposed in between.

[0061] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0062] In this specification, "substitution" means that, unless otherwise defined, at least one hydrogen of a compound is substituted with a C1 to C30 alkyl group; a C1 to C10 alkoxy group; a silane group; an alkylsilane group; an alkoxysilane group; or an ethyleneoxyl group.

[0063] In this specification, "hetero" means an atom selected from the group consisting of N, O, S, and P, unless otherwise defined.

[0064] The above alkyl group may be a C1 to C20 alkyl group, and specifically, may be a C1 to C6 lower alkyl group, a C7 to C10 intermediate alkyl group, or a C11 to C20 higher alkyl group.

[0065] For example, C1 to C4 alkyl groups mean that there are 1 to 4 carbon atoms in the alkyl chain, and this indicates that they are selected from the group consisting of methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and t-butyl.

[0066] Typical alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups.

[0067] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0068]

[0069] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention comprises a urethane resin and an inorganic filler.

[0070] Below, each component is explained separately.

[0071] First, the urethane resin plays a role in lowering the degree of crosslinking of the composition and increasing viscoelastic properties.

[0072] In one embodiment of the present invention, by including a urethane resin having a specific chemical structure, the film adhesion, peel adhesion, high temperature adhesion, thermal conductivity, and interlayer insulation properties 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.

[0073] [Chemical Formula 1]

[0074]

[0075] [Chemical Formula 2]

[0076]

[0077] (R in Chemical Formulas 1 and 2 above 1Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.)

[0078] Chemical formula 1 is a chemical structure derived from an aromatic diisocyanate used as a raw material in the synthesis process of urethane resin.

[0079] Due to the structure of Chemical Formula 1, heat resistance can be improved with hard properties due to the two benzene ring structures within the aromatic diisocyanate.

[0080] R in Chemical Formula 1 1 Each 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. In Formula 1, R 1 It is connected inside the benzene ring, which means it is substituted at any of the six substitution sites of the benzene ring. More specifically, R 1 Each can independently be hydrogen, deuterium, or a substituted or unsubstituted C1 to C10 alkyl group. 1 Each can independently be hydrogen or deuterium.

[0081] L in Chemical Formula 1 1represents a single bond or a divalent linker. Specifically, the divalent linker may 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, or a substituted or unsubstituted C5 to C20 heteroarylene group, -O-, -(CO)-, -S-, -N-, and -P-. More specifically, L 1 ... may be 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. More specifically, L 1 It may be a substituted or unsubstituted C1 to C10 alkylene group.

[0082] Specifically, the repeating unit of Chemical Formula 1 can be represented as shown in Chemical Formula 3 below.

[0083] [Chemical Formula 3]

[0084]

[0085] (R in the above chemical formula 3 1 Each 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. 1 represents a single bond or a divalent linker.

[0086] As in Chemical Formula 3, the connector L 1 By ensuring that the linkers in the -NCOO- group and other repeating units are not bonded to symmetrical positions of the two benzene rings, the film adhesion, peel adhesion, high temperature adhesion, thermal conductivity, and interlayer insulation properties of the manufactured electrical steel sheet laminate can be further improved.

[0087] R in Chemical Formula 3 1 and L1 Since it is identical to the explanation in Chemical Formula 1 above, the redundant explanation is omitted.

[0088] The repeating unit of Formula 1 may be included in an amount of 20 to 50 weight percent within the urethane resin. If the repeating unit of Formula 1 is too small, a problem of reduced high-temperature bonding strength of the urethane resin may occur, and if it is too large, a problem of reduced heat fusion ability may occur. More specifically, the repeating unit of Formula 1 may be included in an amount of 30 to 40 weight percent within the urethane resin. The ratio of the repeating unit of Formula 1 can be controlled through the ratio of aromatic diisocyanate monomers added during the manufacture of the urethane resin.

[0089] Chemical formula 2 is a chemical structure derived from a polyol used as a raw material in the synthesis process of urethane resin.

[0090] Due to the structure of Chemical Formula 2, thermal fusion can be improved due to increased soft properties with multiple -COO- and -O- structures.

[0091] In chemical formula 2, L 2 and L 3 Each represents a single bond or a divalent linker independently. Specifically, the divalent linker may 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, or a substituted or unsubstituted C5 to C20 heteroarylene group, -O-, -(CO)-, -S-, -N-, and -P-. More specifically, L 1 ... may be 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. More specifically, L 1 It may be a substituted or unsubstituted C1 to C10 alkylene group.

[0092] n can be an integer from 1 to 50. If n is too large, problems may arise in terms of heat resistance. More specifically, n can be from 1 to 20.

[0093] The repeating unit of Formula 2 may be included in the urethane resin at a weight of 50 to 80%. If the repeating unit of Formula 2 is too small, a problem of reduced heat sealability may occur. If the repeating unit of Formula 2 is too large, a problem of reduced high-temperature bonding strength of the urethane resin may occur. More specifically, the repeating unit of Formula 2 may be included in the urethane resin at a weight of 60 to 70%. The ratio of the repeating unit of Formula 2 can be controlled through the ratio of polyol added during the manufacture of the urethane resin.

[0094] Urethane resin can be formed by the reaction of a diisocyanate monomer and a polyol represented by the following chemical formula 4.

[0095] [Chemical Formula 4]

[0096]

[0097] (In the above chemical formula 4, L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.)

[0098] Since the polyol of Chemical Formula 4 has been explained in relation to the explanation of the repeating unit of Chemical Formula 2 in the urethane resin, a redundant explanation is omitted. L of Chemical Formula 4 2 , L 3 and n are the same as described in Chemical Formula 2.

[0099] The number average molecular weight of the polyol may be 400 to 1000 g / mol. If the molecular weight is too small, problems may arise in terms of heat sealability. If the molecular weight is too large, problems may arise in terms of heat resistance. More specifically, the number average molecular weight of the polyol may be 500 to 800.

[0100] The aromatic diisocyanate monomer may be a compound represented by the following chemical formula 5.

[0101] [Chemical Formula 5]

[0102]

[0103] (R in the above chemical formula 5 1 to R 10 Each is independently 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, a halogen element, or an isocyanate group, and

[0104] R 1 to R 5 At least one of them is an isocyanate group, and

[0105] R 6 to R 10 At least one of them is an isocyanate group, and

[0106] R 3 and R 8 Cases where it is simultaneously an isocyanate group are excluded, and

[0107] 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, and

[0108] n is an integer from 1 to 10.

[0109] Since the aromatic diisocyanate of Chemical Formula 5 has been explained in relation to the explanation of the repeating unit of Chemical Formula 1 of the urethane resin, a redundant explanation is omitted. R of Chemical Formula 5 1 to R 10 is identical to the explanation of R1 in Chemical Formula 1, and L in Chemical Formula 5 is L in Chemical Formula 1. 1 It is identical to the explanation.

[0110] The aromatic diisocyanate monomer may be represented by the following chemical formula 6.

[0111] [Chemical Formula 6]

[0112]

[0113] (In the above Chemical Formula 2, 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.)

[0114] More specifically, L may be a substituted or unsubstituted C1 to C10 alkylene group. More specifically, L may be a methylene group. The aromatic diisocyanate monomer may be methylene diphenyl diisocyanate.

[0115] The urethane resin may be included in an amount of 50 to 90 parts by weight based on 100 parts by weight of the total of the urethane resin and inorganic filler. If too little urethane resin is included, the vibration suppression effect may be compromised due to the low viscoelastic properties of the composition. If too much urethane resin is included, the high-temperature adhesive strength may be compromised due to the low degree of crosslinking of the composition. More specifically, the urethane resin may be included in an amount of 55 to 85 parts by weight based on 100 parts by weight of the total of the urethane resin and inorganic filler.

[0116] In one embodiment of the present invention, an inorganic filler is included together with a urethane resin. The inorganic filler has high thermal conductivity and low electrical conductivity, and the thermal conductivity is improved in the vertical direction of the laminate, thereby improving motor thermal management.

[0117] The inorganic filler may be included in an amount of 10 to 50 parts by weight based on 100 parts by weight of the total of the urethane resin and the inorganic filler. If too little inorganic filler is included, high-temperature adhesion and thermal conductivity may be inferior. If too much inorganic filler is included, problems may occur in terms of peel adhesion. More specifically, the inorganic filler may be included in an amount of 15 to 45 parts by weight.

[0118] The inorganic filler may include one or more of oxides, nitrides, and carbides. More specifically, the inorganic filler may include one or more of Be, Al, Si, B, and Mg. More specifically, it may include one or more of Al2O3, BeO, AlN, SiC, SiO2, BN, and MgO.

[0119] An 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.

[0120] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include a coupling agent to strengthen the interfacial adhesion between the electrical steel sheet (10) and the fusion layer (20). The coupling agent may include a silane coupling agent, and more specifically, one or more of an epoxy-based silane coupling agent and an amino-based silane coupling agent may be included. Even more specifically, 2(3,4-epoxycyclohexyl) ethyl trimethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane may be included.

[0121] If a coupling agent is further included, it may be included in an amount of 0.2 to 3 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler. If too little coupling agent is included, the effect of strengthening the interfacial adhesion between the electrical steel sheet and the fusion layer may not be sufficiently obtained. If too much coupling agent is included, precipitates may form in the adhesive coating composition due to reactions between the coupling agents. Specifically, it may be included in an amount of 0.2 to 1 part by weight.

[0122] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include a silicone-based wetting agent in the adhesive coating composition to strengthen the interfacial adhesion between the electrical steel sheet (10) and the fusion layer (20). An example of a silicone-based wetting additive may be polyether-modified polydimethylsiloxane. The wetting agent may be added to the bonding composition for the electrical steel sheet to strengthen the interfacial adhesion between the electrical steel sheet and the fusion layer.

[0123] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention may include a wetting agent in an amount of 0.05 to 0.5 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler. If the content of the wetting agent is too high, problems such as defects in the coating layer due to excessive bubble generation in the coating solution may occur, and if the content of the wetting agent is too low, problems such as defects on the coating surface due to reduced wettability of the coating layer may occur. Specifically, it may include 0.05 to 0.15 parts by weight.

[0124] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include a curing agent to control the reactivity of the surface of the adhesive coating layer. The curing agent may include an aliphatic amine-based, aromatic amine-based, amino amine-based, or imidazole-based agent. More specifically, a dicyandiamide-based curing agent may be included.

[0125] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention may include a curing agent in an amount of 0.5 to 2 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler. The curing agent serves to control the reactivity of the surface of the adhesive coating layer. If too little curing agent is included, the curing reaction of the fusion layer is reduced, which may cause a problem of stickiness on the surface of the fusion layer. Conversely, if too much curing agent is added, the fastening strength after low-temperature fusion may be compromised. Specifically, it may include 0.7 to 1.5 parts by weight.

[0126] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include a curing catalyst to improve stickiness defects caused by incomplete curing due to a rapid curing reaction during coil coating. As the curing catalyst, an imidazole-based curing catalyst may be included.

[0127] An electrical steel sheet adhesive coating composition according to one embodiment of the present invention may include a curing catalyst in an amount of 0.1 to 1 weight part with respect to 100 weight parts of the sum of the urethane resin and the inorganic filler. If the content of the curing catalyst is too high, a problem may arise in which the fastening strength after fusion is reduced due to an over-curing reaction, and if the content of the curing catalyst is too low, a problem may arise in which stickiness occurs on the surface of the fusion layer due to incomplete curing. Specifically, it may include 0.3 to 0.7 weight parts.

[0128] In addition to the aforementioned components, the adhesive coating composition may include a solvent to facilitate application and uniformly disperse the components. The solvent may include water, alcohol, etc. The solvent may be included in an amount of 200 to 2,000 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler. In one embodiment of the present invention, "parts by weight" refers to a relative weight ratio.

[0129] In one embodiment of the present invention, an electrical steel sheet is provided.

[0130] An electrical steel sheet according to one embodiment of the present invention comprises an electrical steel sheet substrate; and a fusion layer located on the electrical steel sheet substrate; wherein the fusion layer comprises a urethane resin and an inorganic filler, and the urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2.

[0131] [Chemical Formula 1]

[0132]

[0133] [Chemical Formula 2]

[0134]

[0135] (R in Chemical Formulas 1 and 2 above 1 Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.)

[0136] In one embodiment of the present invention, an electrical steel sheet laminate is provided.

[0137] An electrical steel sheet laminate according to one embodiment of the present invention comprises a plurality of electrical steel sheets; and a fusion layer located between the plurality of electrical steel sheets. FIG. 1 shows a schematic diagram of an electrical steel sheet laminate according to one embodiment of the present invention. As shown in FIG. 1, a plurality of electrical steel sheets are laminated.

[0138] FIG. 2 shows a schematic cross-sectional view of an electrical steel sheet laminate according to one embodiment of the present invention. As shown in FIG. 2, an 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 (20) located between the plurality of electrical steel sheets.

[0139] An 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 by simply using the aforementioned adhesive coating composition to form a fusion layer, without using conventional methods such as welding, clamping, or interlocking.

[0140] At this time, the electrical steel sheet laminate has excellent high-temperature adhesion and high-temperature oil resistance even after thermal fusion.

[0141] Each component is explained in detail below.

[0142] The electrical steel sheet (10) can be any general non-oriented or oriented electrical steel sheet without limitation. In one embodiment of the present invention, since the main configuration is to manufacture an 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.

[0143] The fusion layer (20) is formed between a plurality of electrical steel plates (10), and has strong adhesive strength so that the plurality of electrical steel plates (10) can be bonded without using conventional fastening methods such as welding, clamping, or interlocking.

[0144] The fusion layer (20) is formed by coating an adhesive coating composition on the surface, curing it to form an adhesive coating layer, and then laminating and heat-fusion the layers to form the fusion layer (20). When a plurality of electrical steel sheets (10) having adhesive coating layers are laminated and heat-fused, the resin components within the adhesive coating layers heat-fuse to form the fusion layer.

[0145] In one embodiment of the present invention, the fusion layer (20) comprises a urethane resin and an inorganic filler. Since the urethane resin and the inorganic filler have been described in detail in relation to the adhesive coating composition, a redundant description is omitted. During the process of forming the fusion layer, the chemical structure, ratio, etc., of the urethane resin and the inorganic filler remain unchanged. In addition, the coupling agent, curing agent, curing catalyst, and wetting additive also remain, and their content ranges may be the same as those of the adhesive coating composition. Since the coupling agent, curing agent, curing catalyst, and wetting additive have been described in detail in relation to the adhesive coating composition, a redundant description is omitted.

[0146] The fusion layer (20) may comprise 50 to 90 parts by weight of urethane resin and 10 to 50 parts by weight of inorganic filler, based on a total of 100 parts by weight of urethane resin and inorganic filler.

[0147] Additionally, the fusion layer (20) may further include 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.

[0148] 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 strength may decrease rapidly, and if it is too thick, defects caused by stickiness after coating winding become a problem. More specifically, the thickness of the fusion layer (20) may be 1 μm to 3 μm.

[0149]

[0150] In one embodiment of the present invention, the electrical steel sheet laminate has improved film adhesion, peel adhesion, high temperature adhesion, thermal conductivity, and interlayer insulation properties.

[0151] A method for manufacturing an electrical steel sheet laminate according to one embodiment of the present invention comprises the steps 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 layer; and laminating a plurality of electrical steel sheets having adhesive coating layers formed thereon and heat-fusion to form a fusion layer.

[0152] Below, each step is explained in detail.

[0153] First, prepare an adhesive coating composition. Since the adhesive coating composition has been described previously, a redundant explanation is omitted.

[0154] Next, the adhesive coating composition is coated onto the surface of the electrical steel sheet and then cured to form an adhesive coating layer. This step can be performed at a temperature range of 150 to 250°C to cure the adhesive coating composition.

[0155] A plurality of electrical steel sheets having an adhesive coating layer are laminated and heat-fused to form a fused layer (20). Through the heat-fusion step, the polymer components within the adhesive coating layer heat-fuse and form a fused layer.

[0156] 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 pressurization time of 0.1 to 120 minutes. Each of the above conditions can be satisfied independently, or two or more conditions can be satisfied simultaneously. By controlling the temperature, pressure, and time conditions in the heat fusion step in this way, the electrical steel sheets can be heat-fused densely without gaps or organic material between them.

[0157] The heat fusion step includes a heating step and a fusion step, and the heating rate of the heating step can be 10℃ / min to 1000℃ / min.

[0158]

[0159] Embodiments of the present invention are described below in detail so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0160]

[0161] Experimental Example 1

[0162] Non-oriented electrical steel sheets (50 x 50 mm, 0.35 mmt) were prepared as blank specimens. An adhesive coating solution was applied to the top and bottom of each prepared blank specimen to a uniform thickness using a Bar Coater and a Roll Coater, cured at 200°C for 20 seconds, and then slowly cooled in air to form an adhesive coating layer.

[0163] An adhesive coating solution comprising 100 parts by weight of a polyurethane resin and an inorganic filler, 0.5 parts by weight of a silane coupling agent (3-glycidoxypropyl triethoxysilane), 0.1 parts by weight of a silicone-based wetting agent (polyether-modified siloxane), 1 part by weight of a dicyandiamide-based curing agent (adipic acid dihydrazide), and 0.5 parts by weight of an imidazole-based curing catalyst (1,2-dimethylimidazole) was used.

[0164] The polyurethane resin was prepared by reacting 40% by weight of 2,4-methylene diphenyl diisocyanate monomer with 60% by weight of polyethylene carbonate diol having a moisture content of 425 g / mol, based on the total weight of the polyurethane resin, and then used.

[0165] The content ratio of the polyurethane resin and inorganic filler used, and the types and content ratios of the isocyanate monomer and polyol used in the manufacture of the polyurethane resin are as shown in Table 1 below.

[0166] In Table 1, MDI means methylene diphenyl diisocyanate, TDI means toluene diisocyanate, PCD means polyethylene carbonatediol (moisture molecular weight 425 g / mol), and PPG means polypropylene glycol.

[0167] Electrical steel sheets coated with an adhesive coating layer were laminated to a height of 20 mm, and then heat-fused at 160°C for 10 minutes under pressure of 0.5 MPa to produce an electrical steel sheet laminate. After heat-fusion, the thickness of the fused layer was approximately 3 μm. The heat-fused laminate was evaluated according to the mixing ratio of the mixed resin in the coating composition and the type of aromatic diisocyanate monomer used. Specifically, film adhesion, peel adhesion, high temperature adhesion, thermal conductivity, and interlayer insulation properties were evaluated and are shown in Table 1 below.

[0168] The measurement method for each characteristic is as follows.

[0169]

[0170] Method for measuring film adhesion: Specimen specifications for measuring film adhesion were prepared in accordance with ISO 1519. A coated specimen was prepared as a sample measuring 30 x 300 mm, bent 180° to fit a 10 mm diameter iron cylinder, and then tape was applied to the area. The presence or absence of peeling of the coating layer was then visually observed. If peeling occurred, it was evaluated as NG, and if no peeling occurred, it was judged as OK.

[0171]

[0172] Peel Adhesion (T-peel, N / mm): Specimen specifications for the T-peel-off measurement were prepared in accordance with ISO 11339. Two 25 x 200 mm specimens were prepared as a 25 x 150 mm specimen. 2After bonding over an area, the unbonded portion was bent 90° to fabricate a T-shaped tensile specimen. The specimen fabricated by the T-Peeloff method was fixed to upper and lower jigs with a constant force, and the tensile strength of the stacked sample was measured using a device while pulling at a constant speed. In the case of the shear method, the measured value was determined as the point where the interface with the minimum adhesive strength detached among the interfaces of the stacked samples. The adhesive strength was measured after maintaining the temperature of the specimen at 60°C using a heating device.

[0173]

[0174] High-Temperature Adhesion Evaluation: The shear adhesion strength used to measure high-temperature adhesion was measured using the shear method. Specimen specifications for the shear method measurement were prepared in accordance with ISO 4587. Shear method specimens were fabricated by bonding two 25 x 100 mm specimens with a coating agent to an area of ​​12.5 x 25 mm² and heat-fusion them under the aforementioned conditions. The specimens fabricated by the shear method were placed in a tensioner equipped with a heating furnace. After setting the atmosphere temperature to high, they were fixed to upper and lower jigs with a constant force, and the tensile strength of the stacked samples was measured using a device that measures the tensile strength while pulling at a constant speed. In the case of the shear method, the measured value was determined as the point where the interface with the minimum adhesion strength detached among the interfaces of the stacked samples. The adhesion strength was measured after maintaining the temperature of the specimen at 180°C using a heating device.

[0175]

[0176] Thermal Conductivity: A laminate consisting of 20 sets including a steel plate and a fusion layer was machined to a diameter of 12.8 mm, and a measurement sample was set on a cold plate. After applying a pressure of 1060 to 3000 kPa to the sample, a current of 5 A was applied to a heating diode to raise the temperature, and a sensor current was applied to check the change in voltage according to the product temperature. The thermal resistance values ​​for the equipment and the measurement sample were calculated through the change in the measured voltage. After calculating the thermal resistance for each thickness, the thermal conductivity of the sample was calculated using a linear regression equation that applied the calculated thermal resistance and thickness.

[0177] Interlayer insulation characteristics: The top of the coating was measured using a Franklin measuring instrument in accordance with the ASTM A717 international standard.

[0178]

[0179] Classification Polyurethane Inorganic Filler Aromatic Diisocyanate Polyol Content in Composition (parts by weight) Type Content in Composition (parts by weight) Type Content (weight%) Type Content (weight%) Example 1 2,4'-MDI40PCD6080Al2O320 Example 2 2,4'-MDI40PCD6070Al2O330 Example 3 2,4'-MDI40PCD6060Al2O340 Example 4 2,4'-MDI40PCD6080BeO20 Example 5 2,4'-MDI40PCD6070AlN30 Example 6 2,4'-MDI40PCD6060SiC40 Example 7 2,4'-MDI40PCD6060SiO240 Example 82,4'-MDI40PCD6060BN40 Example 92,4'-MDI40PCD6060MgO40 Comparative Example 12,4'-MDI40PCD60100-Comparative Example 22,4'-MDI40PCD6040Al2O360 Comparative Example 32,4'-TDI30PCD7080Al2O320 Comparative Example 42,2'-MDI40PCD6080Al2O320 Comparative Example 54,4'-MDI40PCD6080Al2O320 Comparative Example 62,4'-TDI30PCD7070Al2O330 Comparative Example 72,2'-MDI40PCD6070Al2O330 Comparative Example 84,4'-MDI40PCD6070Al2O330Comparative Example 92,4-TDI30PCD7060Al2O340Comparative Example 102,2'-MDI40PCD6060Al2O340Comparative Example 114,4'-MDI40PCD6060Al2O340Comparative Example 122,4'-MDI40PPG6070Al2O330

[0180] Classification Film Adhesion Peel-off Adhesion (N / mm) High-Temperature Adhesion (MPa) Thermal Conductivity [W / (mK)] Interlayer Insulation [ohm.cm 2 / lam] Example 1 OK 1.5 2.06 10 Example 2 OK 1.02.07 15 Example 3 OK 0.7 1.58 20 Example 4 OK 0.6 1.39 25 Example 5 OK 1.2 1.57 12 Example 6 OK 1.01 31 20 Example 7 OK 1.3 25 10 Example 8 OK 1.2 1.55 15 Example 9 OK 1.01 57 20 Comparative Example 1 OK 3.5 0.1 33 Comparative Example 2 OK 0.1 3.09 25 Comparative Example 3 OK 0.3 2.56 12 Comparative Example 4 OK 0.4 2.06 11 Comparative Example 5 OK 0.4 0.76 12 Comparative Example 6 OK 0.2 3.27 14 Comparative Example 7 OK 0.3 3.07 16 Comparative Example 8OK0.42.0715Comparative Example 9OK0.23.3822Comparative Example 10OK0.33.5821Comparative Example 11OK0.32.0619Comparative Example 12OK1.00.5820

[0181] As shown in Tables 1 and 2, when polyurethane resin and inorganic filler were mixed and used in an appropriate content ratio as in Examples 1 to 3, and 2,4'-MDI (2,4-methylene diphenyl diisocyanate) was used as the aromatic diisocyanate monomer, excellent characteristics were exhibited for film adhesion, peel adhesion, high temperature adhesion, thermal conductivity, and interlayer strength.

[0182] Comparative Example 1 is a case where only urethane resin is used without mixing inorganic fillers, and in this case, it can be confirmed that while the peel adhesion is excellent, the high-temperature adhesion, thermal conductivity, and interlayer insulation are inferior.

[0183] Comparative Example 2 is a case where less urethane resin was used, and in this case, it can be confirmed that the peel adhesion strength is inferior.

[0184] Comparative Examples 3 to 11 are prepared by changing the aromatic diisocyanate monomer in Examples 1 to 3 to a compound other than 2,4'-MDI (2,4-methylene diphenyl diisocyanate) to prepare an adhesive coating layer.

[0185] In the case of Comparative Examples 3, 6, and 9, which used 2,4'-TDI (2,4-toluene diisocyanate) as the aromatic diisocyanate, it can be confirmed that the peel adhesion strength is inferior compared to the examples.

[0186] In the case of Comparative Examples 4, 7, and 10, in which 2,2'-MDI (2,2-methylene diphenyl diisocyanate) was used as the aromatic diisocyanate, it can be confirmed that the peel adhesion strength is inferior compared to the examples.

[0187] In the case of Comparative Examples 5, 8, and 11, in which 4,4'-MDI (4,4-methylene diphenyl diisocyanate) was used as the aromatic diisocyanate, it can be confirmed that the peel adhesion strength is inferior compared to the examples.

[0188] Comparative Example 12 is an example in which polypropylene glycol was used as the polyol compound. It can be confirmed that the high-temperature adhesive strength is inferior.

[0189]

[0190] The present invention is not limited to the embodiments described above but can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without altering the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

[0191]

[0192] [Explanation of the symbol]

[0193] 100 : Electrical steel sheet laminate 10 : Electrical steel sheet

[0194] 20: Fusion layer

Claims

1. Contains urethane resin and inorganic filler, and The above urethane resin is an electrical steel sheet adhesive coating composition comprising repeating units represented by the following chemical formula 1 and the following chemical formula 2. [Chemical Formula 1] [Chemical Formula 2] (R in Chemical Formulas 1 and 2 above 1 Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.) 2. In Paragraph 1, An electrical steel sheet adhesive coating composition comprising 50 to 90 parts by weight of the urethane resin and 10 to 50 parts by weight of the inorganic filler, based on a total of 100 parts by weight of the urethane resin and the inorganic filler.

3. In Paragraph 1, The above urethane resin is an electrical steel sheet adhesive coating composition comprising repeating units represented by the following chemical formula 3 and the above chemical formula 2. [Chemical Formula 3] (R in the above chemical formula 3 1 Each 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. 1 represents a single bond or a divalent linker.

4. In Paragraph 1, The above urethane resin is an electrical steel sheet adhesive coating composition formed by the reaction of a diisocyanate monomer and a polyol represented by the following chemical formula 4. [Chemical Formula 4] (In the above chemical formula 4, L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.) 5. In Paragraph 4, The above diisocyanate monomer is an electrical steel sheet adhesive coating composition comprising an aromatic diisocyanate monomer.

6. In Paragraph 5, The above aromatic diisocyanate monomer is an electrical steel sheet adhesive coating composition in which the compound is represented by the following chemical formula 5. [Chemical Formula 5] (R in the above chemical formula 5 1 to R 10 Each is independently 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, a halogen element, or an isocyanate group, and R 1 to R 5 At least one of them is an isocyanate group, and R 6 to R 10 At least one of them is an isocyanate group, and R 3 and R 8 Cases where it is simultaneously an isocyanate group are excluded, and 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, and n is an integer from 1 to 10.

7. In Paragraph 1, The above-mentioned inorganic filler is an electrical steel sheet adhesive coating composition comprising one or more of oxides, nitrides, and carbides.

8. In Paragraph 1, The above-mentioned inorganic filler is an electrical steel sheet adhesive coating composition comprising one or more of Be, Al, Si, B, and Mg.

9. In Paragraph 1, An electrical steel sheet adhesive coating composition further comprising one or more selected from the group consisting of coupling agents, wetting agents, curing agents, and curing catalysts.

10. In Paragraph 9, The above coupling agent comprises 0.2 to 3 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler, in an electrical steel sheet adhesive coating composition.

11. In Paragraph 9, An electrical steel sheet adhesive coating composition comprising 0.5 to 2 parts by weight of the curing agent based on 100 parts by weight of the sum of the urethane resin and the inorganic filler.

12. In Paragraph 9, The above curing catalyst comprises 0.1 to 1 weight part per 100 weight parts of the sum of the urethane resin and the inorganic filler, in an electrical steel sheet adhesive coating composition.

13. In Paragraph 9, The above wetting agent comprises 0.05 to 0.5 parts by weight per 100 parts by weight of the sum of the urethane resin and the inorganic filler, in an electrical steel sheet adhesive coating composition.

14. Electrical steel sheet substrate; and A fusion layer located on the electrical steel sheet substrate; comprising The above fusion layer comprises urethane resin and inorganic filler, and The above urethane resin is an electrical steel sheet comprising repeating units represented by the following chemical formula 1 and the following chemical formula 2. [Chemical Formula 1] [Chemical Formula 2] (R in Chemical Formulas 1 and 2 above 1 Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.) 15. Multiple electrical steel sheets; and A fusion layer located between the plurality of electrical steel sheets; comprising The above fusion layer comprises urethane resin and inorganic filler, and The above urethane resin is an electrical steel sheet laminate comprising repeating units represented by the following chemical formula 1 and the following chemical formula 2. [Chemical Formula 1] [Chemical Formula 2] (R in Chemical Formulas 1 and 2 above 1 Each 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. 1 , L 2 , L 3 represents a single bond or a divalent linker, respectively. n represents an integer from 1 to 50.) 16. In Paragraph 15, The above fusion layer is an electrical steel sheet laminate comprising 50 to 90 parts by weight of the urethane resin and 10 to 50 parts by weight of the inorganic filler, based on 100 parts by weight of the sum of the urethane resin and the inorganic filler.

17. A step of forming an adhesive coating layer by applying the adhesive coating composition described in claim 1 to one or both sides of an electrical steel sheet and then curing it. A method for manufacturing an electrical steel sheet laminate comprising the step of laminating a plurality of electrical steel sheets having the adhesive coating layer formed thereon and thermally fusing them to form a fused layer.

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