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

Abstract

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

Description

Technical Field

[0001] One embodiment of the present invention relates to an adhesive coating composition for electrical steel sheets, an electrical steel sheet laminate, and a method for manufacturing the same. Specifically, one embodiment of the present invention relates to an adhesive coating composition for electrical steel sheets, an electrical steel sheet laminate, and a method for manufacturing the same, for forming a fusion layer that can bond (connect) electrical steel sheets without using conventional connection methods such as welding, clamping, or interlocking. More specifically, one embodiment of the present invention relates to an adhesive coating composition for electrical steel sheets, an electrical steel sheet laminate, and a method for manufacturing the same, for improving the adhesive strength and noise reduction properties of the electrical steel sheet laminate by controlling the composition of the fusion layer formed between the electrical steel sheets. Background Technology

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

[0003] Electrical steel sheets can be divided into two types: one requires stress-relief annealing (SRA) to improve the magnetic properties after punching, and the other omits stress-relief annealing when the cost loss caused by heat treatment outweighs the magnetic property effect brought by stress-relief annealing.

[0004] Insulating films, applied as a finishing process in products such as motor and generator cores, electric motors, and small transformers, typically require electrical properties that suppress eddy current generation. In addition, they must possess continuous punching capability, anti-adhesion properties, and surface adhesion resistance. Continuous punching capability refers to the ability to suppress die wear when multiple cores are stacked after being punched into a predetermined shape. Anti-adhesion property refers to the ability of the steel plates in the core to not adhere to each other after a stress-relief annealing process that removes the processing stress from the steel plates and restores their magnetic properties.

[0005] In addition to these basic characteristics, excellent coating operability of the coating liquid and long-term solution stability after preparation are also required. For this type of insulating coating, only other connection methods such as welding, clamping, and interlocking can be used to manufacture electrical steel sheet laminates. Summary of the Invention

[0006] (a) Technical problems to be solved One embodiment of the present invention provides an adhesive coating composition for electrical steel sheets, an electrical steel sheet laminate, and a method for manufacturing the same. Specifically, one embodiment of the present invention provides an adhesive coating composition for electrical steel sheets, an electrical steel sheet laminate, and a method for manufacturing the same, for forming a fusion layer that allows electrical steel sheets to be bonded (connected) without using conventional connection methods such as welding, clamping, or interlocking. More specifically, one embodiment of the present invention provides an adhesive coating composition for electrical steel sheets, an electrical steel sheet laminate, and a method for manufacturing the same, for improving the adhesive strength between electrical steel sheets by controlling the composition of the fusion layer formed between the electrical steel sheets.

[0007] (II) Technical Solution An electrical steel sheet adhesive coating composition according to an embodiment of the present invention comprises urethane resin and a metal inorganic acid salt, wherein the urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2.

[0008] [Chemical Formula 1] [Chemical Formula 2] In chemical formulas 1 and 2, R 1 Each element independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen. 1 L 2 L 3 Each represents a single bond or a binary linker. n represents an integer from 1 to 50.

[0009] Relative to 100 parts by weight of the sum of urethane resin and the metal inorganic acid salt, the urethane resin may contain 50 to 90 parts by weight, and the metal inorganic acid salt may contain 10 to 50 parts by weight.

[0010] Ethyl urethane resin may contain repeating units represented by the following chemical formula 3 and the chemical formula 2.

[0011] [Chemical Formula 3] In the chemical formula 3, R 1 Each element independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen. 1 This indicates a single bond or a divalent linker.

[0012] Ethyl urethane resin can be formed by reacting diisocyanate monomers with polyols represented by the following chemical formula 4.

[0013] [Chemical Formula 4] In the chemical formula 4, L 2 L 3 Each represents a single bond or a binary linker. n represents an integer from 1 to 50.

[0014] Diisocyanate monomers may include aromatic diisocyanate monomers.

[0015] Aromatic diisocyanate monomers can be compounds represented by the following chemical formula 5.

[0016] [Chemical Formula 5] In the chemical formula 5, R 1 To R 10 Each of these elements is independently hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, halogen element, or isocyanate group. R 1 To R 5 At least one of them is an isocyanate group. R 6 To R 10 At least one of them is an isocyanate group. R 3 and R 8 Except for cases where both are isocyanate groups, L is a substituted or unsubstituted C1 to C10 alkylene, a substituted or unsubstituted C2 to C10 ynylene, a substituted or unsubstituted C6 to C20 arylene, or a substituted or unsubstituted C5 to C20 heteroarylene. n is any integer from 1 to 10.

[0017] Metal inorganic acid salts may contain phosphates, silicates, or titanates containing one or more of Al, Mg, Ca, Co, Zn, Zr, and Fe.

[0018] 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 coupling agents, wetting agents, curing agents and curing catalysts.

[0019] The coupling agent may contain 0.2 to 3 parts by weight relative to 100 parts by weight of the total amount of urethane resin and metal inorganic acid salt.

[0020] The curing agent may contain 0.5 to 2 parts by weight relative to 100 parts by weight of the total of urethane resin and metal inorganic acid salt.

[0021] The curing catalyst may contain 0.1 to 1 part by weight relative to 100 parts by weight of the sum of urethane resin and metal inorganic acid salt.

[0022] The wetting agent may contain 0.05 to 0.5 parts by weight relative to 100 parts by weight of the total amount of urethane resin and metal inorganic acid salt.

[0023] An electrical steel sheet laminate according to an embodiment of the present invention comprises: a plurality of electrical steel sheets; and a fusion layer located between the plurality of electrical steel sheets, the fusion layer comprising urethane resin and a metal inorganic acid salt, the urethane resin comprising repeating units represented by the following chemical formula 1 and the following chemical formula 2.

[0024] [Chemical Formula 1] [Chemical Formula 2] In chemical formulas 1 and 2, R 1 Each element independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen. 1 L 2 L 3 Each represents a single bond or a binary linker. n represents an integer from 1 to 50.

[0025] The fusion layer may contain 50 to 90 parts by weight of urethane resin and 10 to 50 parts by weight of metal inorganic acid salt, relative to 100 parts by weight of the sum of urethane resin and metal inorganic acid salt.

[0026] A method for manufacturing an electrical steel sheet laminate according to an embodiment of the present invention includes: 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 laminating and thermally fusing multiple electrical steel sheets having the adhesive coating to form a fusion layer.

[0027] (III) Beneficial Effects According to one embodiment of the present invention, the adhesion between electrical steel sheets can be improved by controlling the composition of the fusion layer formed between the electrical steel sheets.

[0028] According to one embodiment of the present invention, electrical steel plates can be bonded without using traditional connection methods such as welding, clamping, and interlocking, thus resulting in better noise and vibration suppression of the electrical steel plate laminate.

[0029] Furthermore, by using urethane resin with a specific chemical structure, it also exhibits excellent adhesion in automotive transmission fluid environments. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an electrical steel sheet laminate.

[0031] Figure 2 This is a cross-sectional schematic diagram of an electrical steel sheet laminate according to an embodiment of the present invention. Detailed Implementation

[0032] The terms "first," "second," "third," etc., are used to describe 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. Therefore, without departing from the scope of the invention, the first part, component, region, layer, and / or segment described below can also be described as a second part, component, region, layer, and / or segment.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. Unless the context clearly indicates otherwise, the singular forms used herein are intended to include the plural forms as well. As used in the specification, "comprising" can specifically refer to a feature, field, integer, step, action, element, and / or component, but does not exclude the presence or addition of other features, fields, integers, steps, actions, elements, components, and / or groups.

[0034] If one part is described as being on top of another part, then other parts may exist directly on top of or in between. If one part is described as being directly on top of another part, then no other parts exist in between.

[0035] Although not otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in dictionaries should be interpreted as having the same meaning as disclosed in relevant technical literature and herein, and should not be interpreted in an idealized or overly formal sense.

[0036] In this specification, unless otherwise defined, “substitution” means that at least one hydrogen atom in a compound is substituted by a C1 to C30 alkyl; C1 to C10 alkoxy; silyl; alkylsilyl; alkoxysilyl; or ethyleneoxy.

[0037] In this specification, unless otherwise defined, “mixed” means atoms selected from N, O, S and P.

[0038] The alkyl group can be a C1 to C20 alkyl group, specifically, it can be a lower alkyl group of C1 to C6, a middle alkyl group of C7 to C10, or a higher alkyl group of C11 to C20.

[0039] For example, C1 to C4 alkyl refers to an alkyl chain with 1 to 4 carbon atoms, which means it is selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.

[0040] Typical alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0041] In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings to enable those skilled in the art to practice the invention. However, the present invention can be implemented in various different ways and is not limited to the embodiments described herein.

[0042] An electrical steel sheet adhesive composition according to an embodiment of the present invention comprises urethane resin and metal inorganic acid salt.

[0043] Each component will be described below.

[0044] First, urethane resin plays a role in reducing the crosslinking degree of the composition and improving its viscoelastic properties.

[0045] In one embodiment of the invention, by comprising a urethane resin having a specific chemical structure, the coating adhesion, peel strength, or ATF resistance of the manufactured electrical steel sheet laminate can be improved. Specifically, the urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2.

[0046] [Chemical Formula 1] [Chemical Formula 2] In chemical formulas 1 and 2, R 1Each element independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen. 1 L 2 L 3 Each represents a single bond or a binary linker. n represents an integer from 1 to 50.

[0047] Chemical formula 1 is the chemical structure of an aromatic diisocyanate derived from the raw material used in the synthesis of urethane resin.

[0048] Due to the structure of chemical formula 1 and the two benzene ring structures in aromatic diisocyanates, the heat resistance can be improved as a hard property.

[0049] In chemical formula 1, R 1 Each element independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or a halogen element. In Formula 1, R 1 Connected inside the benzene ring, this means substitution to any of the six substitution positions on the benzene ring. More specifically, R 1 Each can be independently hydrogen, deuterium, or a substituted or unsubstituted C1 to C10 alkyl group. R 1 Each can be either hydrogen or deuterium.

[0050] In chemical formula 1, L 1 This indicates a single bond or a divalent linker. Specifically, the divalent linker can be one or more of the following: substituted or unsubstituted C1 to C10 alkylene, substituted or unsubstituted C2 to C10 ynylene, substituted or unsubstituted C6 to C20 arylene, or substituted or unsubstituted C5 to C20 heteroarylene, -O-, -(CO)-, -S-, -N-, and -P-. More specifically, L 1 It can be a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 ynylene 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 can be a substituted or unsubstituted C1 to C10 alkylene group.

[0051] Specifically, the repeating unit of chemical formula 1 can be as shown in chemical formula 3 below.

[0052] [Chemical Formula 3] In the chemical formula 3, R 1Each element independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen. 1 This indicates a single bond or a divalent linker.

[0053] As shown in chemical formula 3, the linker L 1 The -NCOO- group and the linking group that serves as another repeating unit do not bind to the symmetrical position of the two benzene rings, thereby further improving the coating adhesion, peel adhesion, or ATF resistance of the manufactured electrical steel sheet laminate.

[0054] In chemical formula 3, R 1 and L 1 The description is the same as that in Chemical Formula 1 above, so the repeated description is omitted.

[0055] In urethane resin, the repeating unit of Formula 1 can comprise 20 to 50% by weight. If the repeating unit of Formula 1 is too small, the high-temperature bonding strength of the urethane resin may decrease; if it is too large, the thermal fusion properties may decrease. More specifically, in urethane resin, the repeating unit of Formula 1 can comprise 30 to 40% by weight. The proportion of repeating units of Formula 1 can be adjusted by the proportion of aromatic diisocyanate monomers added during the manufacture of the urethane resin.

[0056] Chemical formula 2 is the chemical structure of a polyol used as a raw material in the synthesis of urethane resin.

[0057] Due to the structure of chemical formula 2, the multiple -COO- and -O- structures increase the softness, thereby improving thermal fusion properties.

[0058] In chemical formula 2, L 2 and L 3 Each can independently represent a single bond or a divalent linker. Specifically, the divalent linker can be one or more of the following: substituted or unsubstituted C1 to C10 alkylene, substituted or unsubstituted C2 to C10 ynylene, substituted or unsubstituted C6 to C20 arylene, or substituted or unsubstituted C5 to C20 heteroarylene, -O-, -(CO)-, -S-, -N-, and -P-. More specifically, L 1 It can be a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C2 to C10 ynylene 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 can be a substituted or unsubstituted C1 to C10 alkylene group.

[0059] n can be an integer from 1 to 50. If n is too large, problems may occur regarding heat resistance. More specifically, n can be from 1 to 20.

[0060] In urethane resin, the repeating unit of Formula 2 can comprise 50 to 80% by weight. If there are too few repeating units of Formula 2, a decrease in thermal fusion properties may occur. If there are too many repeating units of Formula 2, a decrease in the high-temperature bonding strength of the urethane resin may occur. More specifically, in urethane resin, the repeating unit of Formula 2 can comprise 60 to 70% by weight. The proportion of repeating units of Formula 2 can be adjusted by the proportion of polyols added during the manufacture of the urethane resin.

[0061] Ethyl urethane resin can be formed by reacting diisocyanate monomers with polyols represented by the following chemical formula 4.

[0062] [Chemical Formula 4] In the chemical formula 4, L 2 L 3 Each represents a single bond or a binary linker. n represents an integer from 1 to 50.

[0063] For polyols of formula 4, a description has already been provided in the description of the repeating unit of formula 2 in urethane resin; therefore, the repeated description is omitted. L of formula 4... 2 L 3 And n is the same as the description of chemical formula 2.

[0064] Polyols can have a number average molecular weight of 400 to 1000 g / mol. If the molecular weight is too small, problems may arise regarding thermal fusion. If the molecular weight is too large, problems may arise regarding heat resistance. More specifically, polyols can have a number average molecular weight of 500 to 800.

[0065] Aromatic diisocyanate monomers can be compounds represented by the following chemical formula 5.

[0066] [Chemical Formula 5] In the chemical formula 5, R 1 To R 10 Each of these elements is independently hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, halogen element, or isocyanate group. R 1 To R 5 At least one of them is an isocyanate group. R6 To R 10 At least one of them is an isocyanate group. R 3 and R 8 Except for cases where both are isocyanate groups, L is a substituted or unsubstituted C1 to C10 alkylene, a substituted or unsubstituted C2 to C10 ynylene, a substituted or unsubstituted C6 to C20 arylene, or a substituted or unsubstituted C5 to C20 heteroarylene. n is any integer from 1 to 10.

[0067] For aromatic diisocyanates of formula 5, a description has already been provided in the relevant description of the repeating unit of formula 1 in urethane resins, therefore the repeated description is omitted. The R of formula 5... 1 To R 10 With R of chemical formula 1 1 The descriptions are the same; L in chemical formula 5 is the same as L in chemical formula 1. 1 The description is the same.

[0068] Aromatic diisocyanate monomers can be represented by the following chemical formula 6.

[0069] [Chemical Formula 6] In the chemical formula 2, L is a substituted or unsubstituted C1 to C10 alkylene, a substituted or unsubstituted C2 to C10 ynynyl, a substituted or unsubstituted C6 to C20 arylene, or a substituted or unsubstituted C5 to C20 heteroarylene.

[0070] More specifically, L may be a substituted or unsubstituted C1 to C10 alkylene group. More specifically, L may be methylene. The aromatic diisocyanate monomer may be methylene diphenyl diisocyanate.

[0071] Based on 100 parts by weight of the sum of urethane resin and the metal inorganic acid salt, the urethane resin may contain 50 to 90 parts by weight. If the content of urethane resin is too low, the vibration damping effect may be poor due to the low viscoelastic properties of the composition. If the content of urethane resin is too high, the high-temperature adhesion may be poor due to the low degree of crosslinking of the composition. More specifically, based on 100 parts by weight of the sum of urethane resin and the metal inorganic acid salt, the urethane resin may contain 55 to 85 parts by weight.

[0072] In one embodiment of the invention, a metal inorganic acid salt is included together with the urethane resin. The metal inorganic acid salt serves to improve the degree of crosslinking, thereby enhancing high-temperature adhesion.

[0073] Metal inorganic acid salts are not particularly restricted, but may contain phosphates, silicates or titanates containing one or more of Al, Mg, Ca, Co, Zn, Zr and Fe.

[0074] More specifically, as a metal inorganic acid salt, it may contain metal phosphates. Metal phosphates may contain various metals without limitation. Specifically, the metal phosphate may contain one or more of Al, Mg, Ca, Co, Zn, Zr, and Fe. More specifically, the metal phosphate may contain one or more of magnesium dihydrogen phosphate (Mg(H2PO4)2) and aluminum dihydrogen phosphate (Al(H2PO4)3). More specifically, it may contain magnesium dihydrogen phosphate (Mg(H2PO4)2) and aluminum dihydrogen phosphate (Al(H2PO4)3). In this case, based on solids, relative to 100 parts by weight of total metal phosphate, the metal phosphate may contain 10 to 60 parts by weight of aluminum dihydrogen phosphate and 40 to 90 parts by weight of magnesium dihydrogen phosphate.

[0075] 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 coupling agents, wetting agents, curing agents and curing catalysts.

[0076] The electrical steel sheet adhesive coating composition according to an embodiment of the present invention may further include a coupling agent to enhance the interfacial adhesion between the electrical steel sheet 10 and the fusion layer 20. As a coupling agent, it may include a silane coupling agent, and more specifically, it may include one or more of epoxy silane coupling agents and amino silane coupling agents. More specifically, it may be 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, or 3-aminopropyltrimethoxysilane.

[0077] When a coupling agent is further included, it may be 0.2 to 3 parts by weight relative to 100 parts by weight of the sum of urethane resin and the metal inorganic acid salt. If the content of the coupling agent is too low, the interfacial adhesion enhancement effect between the electrical steel sheet and the fusion layer may not be sufficiently obtained. If the content of the coupling agent is too high, precipitates may form in the adhesive coating composition due to the reaction between the coupling agents. Specifically, it may be 0.2 to 1 part by weight.

[0078] According to one embodiment of the electrical steel sheet adhesive composition of the present invention, the adhesive composition may further include a silicone wetting agent to enhance the interfacial adhesion between the electrical steel sheet 10 and the fusion layer 20. As a silicone wetting additive, for example, it may be polyether-modified polydimethylsiloxane. The wetting agent can be added to the adhesive composition for electrical steel sheets to enhance the interfacial adhesion between the electrical steel sheet and the fusion layer.

[0079] According to one embodiment of the electrical steel sheet adhesive composition of the present invention, the wetting agent may contain 0.05 to 0.5 parts by weight relative to 100 parts by weight of the sum of urethane resin and metal inorganic acid salt. If the wetting agent content is too high, excessive air bubbles in the coating solution may cause coating defects; conversely, if the wetting agent content is too low, decreased wettability of the coating may lead to defects on the coating surface. Specifically, it may contain 0.05 to 0.15 parts by weight.

[0080] The electrical steel sheet adhesive coating composition according to one embodiment of the present invention may further include a curing agent to adjust the reactivity of the adhesive coating surface. As a curing agent, it may include aliphatic amines, aromatic amines, aminoamines, or imidazoles. More specifically, it may include dicyandiamide-based curing agents.

[0081] According to one embodiment of the electrical steel sheet adhesive coating composition of the present invention, the curing agent may contain 1 to 10 parts by weight relative to 100 parts by weight of the sum of urethane resin and metal inorganic acid salt. The curing agent serves to regulate the reactivity of the adhesive coating surface. If the content of the curing agent is too low, a sticky problem may occur 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 bonding strength may be poor after low-temperature fusion. Specifically, it may contain 1 to 5 parts by weight.

[0082] The electrical steel sheet adhesive composition according to one embodiment of the present invention may further include a curing catalyst to improve the stickiness defects caused by uncured curing due to the rapid curing reaction during coil coating. As a curing catalyst, an imidazole-based curing catalyst may be included.

[0083] According to one embodiment of the electrical steel sheet adhesive composition of the present invention, the curing catalyst may contain 0.1 to 5 parts by weight relative to 100 parts by weight of the sum of urethane resin and metal inorganic acid salt. If the content of the curing catalyst is too high, the adhesion after fusion may be poor due to over-curing reaction; if the content of the curing catalyst is too low, the surface of the fused layer may be sticky due to lack of curing. Specifically, it may contain 0.5 to 3 parts by weight.

[0084] In addition to the aforementioned components, the adhesive coating composition may contain a solvent to facilitate application and ensure uniform dispersion of the components. Water, ethanol, etc., may be included as the solvent. The solvent may comprise 200 to 2000 parts by weight relative to 100 parts by weight of the sum of the urethane resin and the metal inorganic acid salt. In one embodiment of the invention, parts by weight refers to a relative weight ratio.

[0085] One embodiment of the present invention provides an electrical steel sheet laminate.

[0086] An electrical steel sheet laminate according to an embodiment of the present invention comprises: a plurality of electrical steel sheets; and a fusion layer located between the plurality of electrical steel sheets. Figure 1 The diagram shows a schematic representation of an electrical steel sheet laminate according to an embodiment of the present invention. Figure 1 As shown, it has multiple layers of electrical steel plates stacked together.

[0087] Figure 2 The diagram shows a cross-sectional schematic of an electrical steel sheet laminate according to an embodiment of the present invention. Figure 2 As shown, an electrical steel sheet laminate 100 according to an 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.

[0088] According to one embodiment of the present invention, the electrical steel sheet laminate can be a laminate in which different electrical steel sheets are thermally fused together without using traditional methods such as welding, clamping, or interlocking.

[0089] At this point, the electrical steel sheet laminate has excellent high-temperature adhesion and high-temperature oil resistance after hot fusion.

[0090] Each component will be described in detail below.

[0091] The electrical steel sheet 10 can be made of any type of non-oriented or oriented electrical steel sheet without limitation. In one embodiment of the invention, the main technical feature is the manufacture of the electrical steel sheet laminate 100 by forming a fusion layer 20 between multiple electrical steel sheets 10; therefore, a detailed description of the electrical steel sheets 10 is omitted. More specifically, the electrical steel sheet 10 can be a non-oriented electrical steel sheet.

[0092] The fusion layer 20 is formed between multiple electrical steel plates 10, and its adhesive force is very strong. It is sufficient to bond multiple electrical steel plates 10 without using traditional connection methods such as welding, clamping, and interlocking.

[0093] For the fusion layer 20, the adhesive coating composition is applied to the surface and cured to form an adhesive coating, and then laminated and thermally fused to form the fusion layer 20. When multiple electrical steel plates 10 with adhesive coatings are laminated and thermally fused, the resin components in the adhesive coatings will thermally fuse to form the fusion layer.

[0094] In one embodiment of the present invention, the fusion layer 20 comprises urethane resin and a metal inorganic acid salt. The urethane resin and the metal inorganic acid salt have been described in detail in the description of the adhesive coating composition, and therefore will not be repeated. During the formation of the fusion layer, the chemical structure, ratio, etc., of the urethane resin and the metal inorganic acid salt remain unchanged. Furthermore, coupling agents, curing agents, curing catalysts, and wetting additives also remain, and their content ranges may be the same as those in the adhesive coating composition. The coupling agents, curing agents, curing catalysts, and wetting additives have been described in detail in the description of the adhesive coating composition, and therefore will not be repeated.

[0095] The fusion layer 20 may contain 50 to 90 parts by weight of urethane resin and 10 to 50 parts by weight of metal inorganic acid salt, relative to 100 parts by weight of the sum of urethane resin and the metal inorganic acid salt.

[0096] In addition, the fusion layer 20 may also contain 0.2 to 3 parts by weight of coupling agent, 0.05 to 0.5 parts by weight of wetting agent, 0.5 to 2 parts by weight of curing agent and 0.1 to 1 part by weight of curing catalyst.

[0097] The thickness of the fusion layer 20 can be from 1 μm to 8 μm. If the fusion layer is too thin, the adhesive strength will drop rapidly, while if it is too thick, defects caused by stickiness after coating and winding will become a problem. More specifically, the thickness of the fusion layer 20 can be from 1 μm to 3 μm.

[0098] In one embodiment of the invention, the electrical steel sheet laminate improves coating adhesion, peel strength, or ATF resistance. If the drive motor is used in an automobile, it generates significant heat during high-speed, prolonged rotation, requiring cooling with ATF (automatic transmission fluid). Therefore, maintaining the adhesion of the laminated coils while immersed in high-temperature ATF is crucial to ensure bonding reliability over long-term use.

[0099] A method for manufacturing an electrical steel sheet laminate according to an embodiment of the present invention includes: 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 laminating and thermally fusing multiple electrical steel sheets having the adhesive coating to form a fusion layer.

[0100] Each step will be described in detail below.

[0101] First, prepare the adhesive coating composition. As for the adhesive coating composition, it has been described previously, so a repetition is omitted.

[0102] Next, the adhesive coating composition is applied to the surface of the electrical steel sheet and then cured to form an adhesive coating. This step can be performed at a temperature of 150 to 250°C to allow the adhesive coating composition to cure.

[0103] Multiple electrical steel sheets with adhesive coatings are stacked and thermally fused together to form a fusion layer 20. Through the thermal fusion step, the polymer components in the adhesive coating are thermally fused together, thereby forming the fusion layer.

[0104] For the thermal fusion step, thermal fusion can be carried out at 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. These conditions can be met individually or simultaneously in multiple ways. Thus, by adjusting the temperature, pressure, and time conditions in the thermal fusion step, a tight thermal fusion can be achieved, eliminating gaps or organic phases between the electrical steel sheets.

[0105] The thermal fusion step includes a heating step and a fusion step. The heating rate of the heating step can be from 10°C / min to 1000°C / min.

[0106] The embodiments of the present invention will be described in detail below to enable those skilled in the art to readily implement the invention. However, the present invention can be implemented in various different ways and is not limited to the embodiments described below.

[0107] Experimental Example 1 Prepare non-oriented electrical steel sheets (50 x 50 mm, 0.35 mm thick) as samples. Apply the adhesive coating liquid to the top and bottom of each prepared sample to a certain thickness using a bar coater and a roller coater. After curing at 200°C (based on the plate temperature) for 20 seconds, allow it to cool slowly in air to form an adhesive coating.

[0108] The adhesive coating liquid used contained 100 parts by weight of polyurethane resin and metal inorganic acid salt, 0.5 parts by weight of silane coupling agent (3-glycidoxypropyltriethoxysilane), 0.1 parts by weight of silicone wetting agent (polyether modified siloxane), 1 part by weight of dicyandiamide curing agent (adipic acid dihydrazide), and 0.5 parts by weight of imidazole curing catalyst (1,2-dimethylimidazole).

[0109] For polyurethane resins, the product is manufactured by reacting 40 wt% of 2,4-methylene diphenyl diisocyanate monomer and 60 wt% of polyethylene carbonate diol with a number average molecular weight of 425 g / mol, based on the total amount of polyurethane resin. Aluminum phosphates were used as the metal inorganic acid salts.

[0110] The ratio of polyurethane resin to aluminophosphate used, as well as the types and contents of isocyanate monomers and polyols used to manufacture the polyurethane resin, are shown in Table 1 below.

[0111] In Table 1, MDI represents methylene diphenyl diisocyanate, TDI represents toluene diisocyanate, and PCD represents polyethylene carbonate diol (number average molecular weight of 425 g / mol).

[0112] Electrical steel sheets coated with an adhesive layer were stacked to a height of 20 mm, then pressurized at 0.5 MPa and heat-fused at 160°C for 10 minutes to produce an electrical steel sheet laminate. The thickness of the fused layer after heat fusion was approximately 3 μm. The heat-fused laminate was evaluated based on the mixing ratio of the mixed resins in the coating composition and the type of aromatic diisocyanate monomer used. Specifically, coating adhesion, peel adhesion (T-peel, N / mm), ATF resistance, and high-temperature adhesion were evaluated and are shown in Table 1 below.

[0113] The methods for determining each characteristic are as follows: Coating adhesion test method: Prepare a specimen for testing coating adhesion according to ISO 1519 specifications. Prepare a 30×300mm sample after coating, bend it 180° onto a 10mm diameter iron cylinder, apply tape to the bend, and visually inspect for coating peeling. If peeling occurs, it is considered non-compliant (NG); if no peeling occurs, it is considered compliant (OK).

[0114] Peel strength (T-peel, N / mm): Specimens prepared according to ISO 11339 for the T-peel method (T-peel off) test. Two 25×200mm specimens are bonded together to form a 25×150mm area. 2 Next, the unbonded portion is bent 90° to create a T-shaped tensile specimen. The specimen, prepared by the peel method (T-peel off), is fixed to the upper / lower jig with a certain force and then stretched at a certain speed. The tensile force is measured using an apparatus for measuring the tensile force of laminated samples. In this case, under the shear method, the measured value is determined at the point of detachment at the interface with the minimum adhesive force in the laminated sample. The specimen temperature is maintained at 60°C using a heating device, and then the adhesive force is measured.

[0115] ATF resistance evaluation method: The manufactured laminated coil was immersed in ATF (SP4M-1) at 160°C for 1000 hours, and the shear bond strength was tested. The shear bond strength used to determine the ATF resistance was determined by the shear strength method. Test specimens for the shear strength test were prepared according to ISO 4587. Two 25×100mm specimens were bonded together to form a 12.5×25mm² specimen. 2 The specimens are then thermally fused under the aforementioned conditions to prepare a shear test specimen. The specimen prepared by the shear test is fixed to an upper / lower jig (JIG) with a certain force, and then stretched at a certain speed. The tensile force is measured using a device for measuring the tensile force of laminated samples. In this case, under the shear test, the measured value is the point at which the interface with the minimum adhesive force in the laminated sample detaches.

[0116] High-Temperature Adhesion Strength Evaluation: The shear adhesion strength used to determine high-temperature adhesion strength is measured using the shear strength method. Test specimens for the shear strength method were prepared according to ISO 4587. Two 25×100mm specimens were bonded together using a coating agent to form a 12.5×25mm² specimen. 2Under the aforementioned conditions, thermal fusion was performed to prepare shear test specimens. After setting a high ambient temperature in a tensile testing machine equipped with a heating furnace, the shear test specimens were fixed to upper / lower jigs (JIGs) with a certain force, and then stretched at a certain speed. The tensile force was measured using a device for measuring the tensile force of laminated samples. In this case, under the shear test, the measured value is the point at which the interface with the minimum adhesive force in the laminated sample detaches. The temperature of the specimen was maintained at 180°C using a heating device, and then the adhesive force was measured.

[0117] Table 1 As shown in Table 1, similar to Examples 1 to 3, when polyurethane resin and metal inorganic acid salts were mixed in appropriate proportions and 2,4'-MDI (2,4-methylene diphenyl diisocyanate) was used as an aromatic diisocyanate monomer, the coating adhesion, peel adhesion, ATF resistance and high temperature adhesion all exhibited excellent properties.

[0118] Comparative Example 1 uses only urethane resin without mixing with metal inorganic acid salts. In this case, the peel adhesion is excellent, but the high-temperature adhesion and ATF resistance values ​​are less than 1 MPa, which confirms that the high-temperature adhesion and ATF resistance are poor.

[0119] Comparative Example 2 uses a small amount of urethane resin. In this case, the high-temperature adhesion and ATF resistance are excellent, but the peel adhesion value is less than 0.5, which confirms that the adhesion is poor.

[0120] Comparative Examples 3 to 11 were adhesive coatings made by replacing the aromatic diisocyanate monomers in Examples 1 to 3 with compounds other than 4'-MDI (2,4-methylene diphenyl diisocyanate).

[0121] Comparative Examples 3, 6, and 9, which use 2,4'-TDI (2,4-toluene diisocyanate) as an aromatic diisocyanate, confirmed good coating adhesion, ATF resistance, and high-temperature adhesion, but poorer peel adhesion than the examples.

[0122] Comparative Examples 4, 7, and 10, which use 2,2'-MDI (2,2-methylene diphenyl diisocyanate) as an aromatic diisocyanate, also confirmed good coating adhesion, ATF resistance, and high-temperature adhesion, but the peel adhesion was worse than that of the examples.

[0123] Comparative Examples 5, 8, and 11, which use 4,4'-MDI (4,4-methylene diphenyl diisocyanate) as an aromatic diisocyanate, confirmed good coating adhesion and high-temperature adhesion, but poorer peel adhesion and ATF resistance than the examples.

[0124] Comparative Example 12 is an example of the use of polypropylene glycol as a polyol compound. It can be confirmed that the coating has good adhesion, peel strength and ATF resistance, but poor high-temperature adhesion.

[0125] This invention can be implemented in various ways and is not limited to the embodiments described herein. Those skilled in the art will understand that the invention can be implemented in other specific ways without altering its technical concept or essential features. Therefore, it should be understood that the above embodiments are exemplary in all respects and are not restrictive.

[0126] [Explanation of reference numerals in the attached figures] 100: Electrical steel sheet laminate; 10: Electrical steel sheet 20: Fusion layer

Claims

1. A coating composition for bonding electrical steel sheets, wherein, The composition comprises urethane resin and a metal inorganic acid salt. The urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2. [Chemical Formula 1] ， [Chemical Formula 2] ， In chemical formulas 1 and 2, R 1 Each independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen element, L 1 L 2 L 3 Each represents a single bond or a binary linker, and n represents an integer from 1 to 50.

2. The electrical steel sheet adhesive coating composition according to claim 1, wherein, Relative to 100 parts by weight of the urethane resin and the metal inorganic acid salt, the urethane resin comprises 50 to 90 parts by weight, and the metal inorganic acid salt comprises 10 to 50 parts by weight.

3. The electrical steel sheet adhesive coating composition according to claim 1, wherein, The urethane resin comprises 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, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen element, L 1 This indicates a single bond or a divalent linker.

4. The electrical steel sheet adhesive coating composition according to claim 1, wherein, The urethane resin is formed by reacting a diisocyanate monomer with a polyol represented by the following chemical formula 4. [Chemical Formula 4] ， In the chemical formula 4, L 2 L 3 Each represents a single bond or a binary linker, 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 comprises 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 Each of these elements is independently hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, halogen element, or isocyanate group. R 1 To R 5 At least one of them is an isocyanate group. R 6 To R 10 At least one of them is an isocyanate group. R 3 and R 8 Except for cases where both are isocyanate groups, L is a substituted or unsubstituted C1 to C10 alkylene, a substituted or unsubstituted C2 to C10 ynylene, a substituted or unsubstituted C6 to C20 arylene, or a substituted or unsubstituted C5 to C20 heteroarylene. n is any integer from 1 to 10.

7. The electrical steel sheet adhesive coating composition according to claim 1, wherein, The metal inorganic acid salts include phosphates, silicates, or titanates containing one or more of Al, Mg, Ca, Co, Zn, Zr, and Fe.

8. The electrical steel sheet adhesive coating composition according to claim 1, wherein, The composition further comprises one or more of the group consisting of coupling agents, wetting agents, curing agents and curing catalysts.

9. The electrical steel sheet adhesive coating composition according to claim 8, wherein, The coupling agent comprises 0.2 to 3 parts by weight relative to 100 parts by weight of the sum of the urethane resin and the metal inorganic acid salt.

10. The electrical steel sheet adhesive coating composition according to claim 8, wherein, The curing agent comprises 0.5 to 2 parts by weight relative to 100 parts by weight of the sum of the urethane resin and the metal inorganic acid salt.

11. The electrical steel sheet adhesive coating composition according to claim 8, wherein, The curing catalyst comprises 0.1 to 1 part by weight relative to 100 parts by weight of the sum of the urethane resin and the metal inorganic acid salt.

12. The electrical steel sheet adhesive coating composition according to claim 8, wherein, The wetting agent comprises 0.05 to 0.5 parts by weight relative to 100 parts by weight of the sum of the urethane resin and the metal inorganic acid salt.

13. An electrical steel sheet laminate, comprising: Multiple electrical steel plates; and A fusion layer, which is located between the plurality of electrical steel plates, The fusion layer comprises urethane resin and metal inorganic acid salt. The urethane resin comprises repeating units represented by the following chemical formula 1 and the following chemical formula 2. [Chemical Formula 1] ， [Chemical Formula 2] ， In chemical formulas 1 and 2, R 1 Each independently represents hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted C5 to C20 heteroaryl, hydroxyl, or halogen element, L 1 L 2 L 3 Each represents a single bond or a binary linker, and n represents an integer from 1 to 50.

14. The electrical steel sheet laminate according to claim 13, wherein, The fusion layer comprises 50 to 90 parts by weight of the urethane resin and 10 to 50 parts by weight of the metal inorganic acid salt, relative to 100 parts by weight of the sum of the urethane resin and the metal inorganic acid salt.

15. A method for manufacturing an electrical steel sheet laminate, comprising: The steps of applying the adhesive coating composition of claim 1 to one or both sides of an electrical steel sheet and then curing it to form an adhesive coating; and The step of stacking and thermally fusing multiple electrical steel sheets with the adhesive coating to form a fusion layer.

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