Electromagnetic steel sheet adhesive coating composition, electromagnetic steel sheet laminate, and method for producing the same

Abstract

The present invention provides an electrical steel sheet laminate with a fusion layer that can bond (fasten) electrical steel sheets without using conventional fastening methods such as welding, clamping, interlocking, etc., and a method for manufacturing the same. Specifically, the present invention provides an electrical steel sheet adhesive coating composition that improves the adhesive strength between electrical steel sheets by controlling the components of the fusion layer formed between the electrical steel sheets. The adhesive composition includes an adhesive resin and a bonding additive, The adhesive resin is a polyurethane formed by reacting a diisocyanate monomer with a polyol, the diisocyanate monomer includes an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer, and the diisocyanate monomer includes 50 parts by weight or less of an aliphatic diisocyanate monomer per 100 parts by weight of the total diisocyanate monomer.

Description

Technical Field

[0001] The present invention relates to an electromagnetic steel sheet adhesive coating composition, an electromagnetic steel sheet laminate, and a method for manufacturing the same, and more particularly, to an electromagnetic steel sheet adhesive coating composition containing a urethane resin, an electromagnetic steel sheet laminate, and a method for manufacturing the same.

Background Art

[0002] Non-oriented electromagnetic steel sheets are steel sheets with uniform magnetic properties in all directions on the rolled plate, and are widely used in cores of motors, generators, electric motors, small transformers, etc. Electromagnetic steel sheets can be classified into two forms: one that must undergo stress relief annealing (SRA) to improve magnetic properties after punching, and the other that omits stress relief annealing when the cost loss due to heat treatment is greater than the magnetic property effect due to stress relief annealing. The insulating film is a film coated in the finishing manufacturing process of laminates such as cores of motors, generators, electric motors, small transformers, etc., and usually requires electrical properties to suppress the generation of eddy currents. In addition, continuous punching processability, anti-adhesion property, and surface adhesion property are also required. The continuous punching processability means the ability to suppress the wear of the die when punching into a predetermined shape and then laminating a large number of them to form a core. The anti-adhesion property means the ability not to adhere between the core steel sheets after the stress relief annealing process that removes the processing stress of the steel sheet and restores the magnetic properties. In addition to such basic properties, excellent coating workability of the coating solution and solution stability that allows long-term use after compounding are also required. Such an insulating film must use a separate fastening method such as welding, clamping, or interlocking to manufacture as an electromagnetic steel sheet laminate.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Provided are an electromagnetic steel sheet laminate having a fusion layer capable of bonding electromagnetic steel sheets without using conventional fastening methods such as welding, clamping, and interlocking, and a method for manufacturing the same. Specifically, provided is an electromagnetic steel sheet adhesive coating composition in which the components of the fusion layer formed between the electromagnetic steel sheets are controlled to improve the adhesive force between the electromagnetic steel sheets.

Means for Solving the Problems

[0004] The bonding composition for electromagnetic steel sheets of the present invention contains an adhesive resin and a bonding additive, the adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol, and the diisocyanate monomer includes an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer. The diisocyanate monomer contains 50 parts by weight or less of an aliphatic diisocyanate monomer with respect to 100 parts by weight in total of the diisocyanate monomer. The aromatic diisocyanate monomer is a monomer represented by the following Chemical Formula 1, Chemical Formula 2, or a combination thereof.

[0005] [Chemical Formula 1] TIFF0007701978000001.tif54129

[0006] [Chemical Formula 2] TIFF0007701978000002.tif64131

[0007] In the Chemical Formula 1, R 1 ~R 10 are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, or an isocyanate group, R 1 ~R 5 any one of them is isocyanate, and R 6 ~R 10 any one of them is isocyanate, L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group, n is any integer from 1 to 10, In the chemical formula 2, R 11 ~R 16 are, independently of one another, hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C5-C20 heteroaryl group, an isocyanate group or a substituted or unsubstituted C1-C10 alkyl isocyanate group, R 11 ~R 16 At least two of them are isocyanate or a substituted or unsubstituted C1-C10 alkyl isocyanate. The aliphatic diisocyanate monomer is a monomer represented by the following chemical formula 3.

[0008] [Chemical formula 3] TIFF0007701978000003.tif9128 In the chemical formula 3, R is a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C3-C12 cycloalkyl group. The aromatic diisocyanate monomer is one or more selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, p-phenylene diisocyanate, 2,2'-methylene diphenyl diisocyanate, 2,4'-methylene diphenyl diisocyanate, 4,4'-methylene diphenyl diisocyanate, m-xylene diisocyanate.

[0009] The aliphatic diisocyanate monomer is at least one selected from the group consisting of hexamethylene diisocyanate (HDI), 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hydrogenated xylene diisocyanate.

[0010] The bonding composition for the electromagnetic steel sheet has a glass transition temperature (Tg) of more than -70°C and less than -10°C, a tensile strength of more than 40 MPa and less than 120 MPa, and an elongation rate of more than 100% and less than 800%.

[0011] The electromagnetic steel sheet of the present invention includes an electromagnetic steel sheet substrate and a bonding coating layer located on the electromagnetic steel sheet substrate. The bonding coating layer includes an adhesive resin and a bonding additive. The adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol. The diisocyanate monomer includes an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer.

[0012] The electromagnetic steel sheet laminate of the present invention includes a plurality of electromagnetic steel sheets and a fusion layer located between the plurality of electromagnetic steel sheets. The fusion layer includes an adhesive resin and a bonding additive. The adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol. The diisocyanate monomer includes an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer.

Advantages of the Invention

[0013] According to the present invention, the adhesion between electromagnetic steel sheets can be improved by controlling the components of the fusion layer formed between the electromagnetic steel sheets. In addition, the electromagnetic steel sheets can be adhered without using conventional fastening methods such as welding, clamping, and interlocking. It is possible to provide an electromagnetic steel sheet adhesive coating composition that is excellent in all of film adhesion, peel characteristics, and ATF resistance.

Embodiments for Carrying Out the Invention

[0014] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Therefore, the first part, component, region, layer, or section described below can be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention. The technical terms used herein are for referring to specific embodiments only and are not intended to limit the present invention. The singular forms used herein include the plural forms as well, unless the context clearly indicates the contrary. The meaning of "including" used in the specification does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components while specifying a particular characteristic, region, integer, step, operation, element, and / or component.

[0015] When a part is "on" or "above" another part, this means that it is directly on or above the other part, or another part may be interposed therebetween. Conversely, when a part is "directly on" another part, no other part is interposed therebetween. Unless otherwise defined, all terms including the technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. Terms defined in commonly used dictionaries are further analyzed and interpreted to have meanings consistent with the relevant technical literature and the presently disclosed content, and are not interpreted in an ideal or overly formal sense unless defined otherwise.

[0016] As used herein, "substitution" means that at least one hydrogen in a compound is substituted with a C1-C30 alkyl group; a C1-C10 alkoxy group; a silane group; an alkylsilane group; an alkoxysilane group; or an ethyleneoxyl group, unless otherwise defined. As used herein, "hetero" means an atom selected from the group consisting of N, O, S, and P, unless otherwise defined.

[0017] The alkyl group may be a C1-C20 alkyl group, specifically a C1-C6 lower alkyl group, a C7-C10 middle alkyl group, or a C11-C20 higher alkyl group. For example, a C1-C4 alkyl group means that there are 1 to 4 carbon atoms in the alkyl chain, and this is selected from the group consisting of methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and t-butyl. Typical alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, etc.

[0018] Hereinafter, the embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. However, the present invention can be realized in various different forms and is not limited to the embodiments described herein. The present invention provides a bonding composition for electromagnetic steel sheets. The term "adhesive coating composition" in the description of the present invention is also a term used to indicate a bonding composition. Further, the bonding composition of the present invention is a composition for bonding the surfaces of two or more steel sheets, and its use is not particularly limited. For example, it may be a self-bonding composition for electromagnetic steel sheets for providing self-bonding of electromagnetic steel sheets.

[0019] The bonding composition for an electromagnetic steel sheet of the present invention contains an adhesive resin and a bonding additive, the adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol, and the diisocyanate monomer may contain an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer. The diisocyanate monomer may contain 50 parts by weight or less of an aliphatic diisocyanate monomer based on 100 parts by weight in total of the diisocyanate monomers. Specifically, the aliphatic diisocyanate monomer may be contained in an amount of more than 0 to 50 parts by weight or 20 to 40 parts by weight based on 100 parts by weight in total of the diisocyanate monomers.

[0020] Both the aromatic isocyanate monomer and the aliphatic isocyanate monomer can form hard segments in the polyurethane. However, due to the difference in molecular structural characteristics between the two, there is a difference in the degree of hardness of the structure. The aromatic isocyanate monomer has a higher molecular structural hardness than the aliphatic isocyanate monomer. Therefore, when the aromatic isocyanate monomer is contained in a larger amount than the aliphatic isocyanate monomer, the hardness of the hard segments of the obtained polyurethane is further increased. That is, a bonding composition with high hardness can be obtained. Therefore, the more the aromatic isocyanate monomer is contained compared to the aliphatic isocyanate monomer, the better the tensile strength characteristics of the bonding liquid, but the elongation rate is inferior and the peel strength characteristics are inferior.

[0021] On the contrary, the more the aliphatic isocyanate monomer is contained compared to the aromatic isocyanate monomer, the better the elongation rate of the bonding liquid, but the tensile strength characteristics are inferior and the AFT resistance characteristics are also inferior. Therefore, in order to provide a bonding composition excellent in both peel strength and AFT resistance characteristics, the ratio of the aliphatic isocyanate and the aromatic isocyanate monomer must be controlled within the range disclosed in the present invention. The aromatic diisocyanate monomer may be a monomer represented by the following Chemical Formula 1, Chemical Formula 2, or a combination thereof.

[0022] [Chemical Formula 1] TIFF0007701978000004.tif54129

[0023] [Chemical Formula 2] TIFF0007701978000005.tif64131

[0024] In the above Chemical Formula 1, R 1 ~R 10 are independently of each other hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, or an isocyanate group, R 1 ~R 5 any one of which is isocyanate, R 6 ~R 10 any one of which is isocyanate, L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group, n is any integer from 1 to 10.

[0025] In the above Chemical Formula 2, R 11 ~R 16 are independently of each other hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, an isocyanate group or a substituted or unsubstituted C1-C10 alkyl isocyanate group, R 11 ~R 16 at least two of which are isocyanate or a substituted or unsubstituted C1-C10 alkyl isocyanate. The aliphatic diisocyanate monomer may be a monomer represented by the following Chemical Formula 3.

[0026] [Chemical Formula 3] TIFF0007701978000006.tif9128In Chemical Formula 3, R is a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C3-C12 cycloalkyl group. The monomer represented by Chemical Formula 1 is R 1 ~R 5 Any one of them is isocyanate, and R 6 ~R 10 Any one of them is isocyanate, and R 3 and R 8 When both are isocyanate, it is excluded, and R 1 and R 10 When both are isocyanate, it can be further excluded.

[0027] The monomer represented by Chemical Formula 1 is R 1 ~R 5 Any one of them is isocyanate, and R 6 ~R 10 Any one of them is isocyanate, and R 1 ~R 5 Any one of them and R 6 ~R 10 It can be further excluded that any one of them and any one of R Specifically, the monomer represented by Chemical Formula 1 can be the one represented by the following Chemical Formula 4.

[0028] [Chemical Formula 4] TIFF0007701978000007.tif43128In Chemical Formula 4, L can be a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group. Specifically, in Chemical Formula 1 or 4, L can be a methylene group. Specifically, the monomer represented by the chemical formula 2 may be the one represented by the following chemical formula 5.

[0029] [Chemical formula 5] TIFF0007701978000008.tif58133 In the chemical formula 5, R 11 may be hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C5-C20 heteroaryl group. More specifically, the aromatic diisocyanate monomer represented by chemical formula 1, 2, 4, or 5 may be one or more selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, p-phenylene diisocyanate, 2,2'-methylenediphenyl diisocyanate, 2,4'-methylenediphenyl diisocyanate, 4,4'-methylenediphenyl diisocyanate, and m-xylene diisocyanate.

[0030] The aliphatic diisocyanate monomer represented by the chemical formula 3 may be one or more selected from the group consisting of hexamethylene diisocyanate (HDI), 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hydrogenated xylene diisocyanate. The polyol may be the polyol of chemical formula 6.

[0031] [Chemical formula 6] TIFF0007701978000009.tif7128 In the chemical formula 6, R' may be a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C5-C20 heteroaryl group. The polyol may have a number average molecular weight of 400-1000 g / mol. Also, the polyol may be poly(propylene glycol).

[0032] The bonding composition for the electromagnetic steel sheet may have a glass transition temperature (Tg) of more than -70°C and less than -10°C, a tensile strength of more than 40 MPa and less than 120 MPa, and an elongation at break of more than 100% and less than 800%. Specifically, the glass transition temperature may be -60°C to -20°C or -50°C to -30°C, the tensile strength may be 50 MPa to 100 MPa or 60 MPa to 70 MPa, and the elongation at break may be 300 to 600% or 400 to 500%. The polyol that reacts with the diisocyanate monomer to form polyurethane may have a number average molecular weight of 400 to 1000 g / mol. Also, the polyol may be poly(propylene glycol).

[0033] The content of the polyurethane resin in the bonding composition for the electromagnetic steel sheet may be 98% by weight or more based on the total weight of the bonding composition for the electromagnetic steel sheet. The bonding composition for the electromagnetic steel sheet of the present invention can exhibit excellent steel sheet adhesion by minimizing the content of other components other than the resin component contained in the composition and maximizing the content of the resin component. The other other components are not limited as long as they are those used in general bonding compositions. For example, coupling agents, wetting agents, curing agents, curing catalysts, etc. may be included.

[0034] Specifically, the coupling agent may include a silane coupling agent. More specifically, one or more of vinyl-based silane coupling agents and methacryloxy-based silane coupling agents may be included. Examples of vinyl-based silane coupling agents include Vinyl trimethoxy silane and Vinyl triethoxy silane. Examples of methacryloxy-based silane coupling agents include 3-Methacryloxypropyl methyldimethoxysilane, 3-Methacryloxpropyl trimethoxysilane, 3-Methacyloxypropyl methyldiethoxysilane, and 3-Methacryloxpropyl triethoxysilane.

[0035] Specifically, the wetting agent may include a silicone-based wetting agent. An example of a silicone-based wetting additive is Polyether-modified polydimethylsiloxane. The wetting agent can be added to the bonding composition for electromagnetic steel sheets to enhance the interfacial adhesion between the electromagnetic steel sheet and the fusion layer. Specifically, the curing agent may include aliphatic amine-based, aromatic amine-based, aminoamine-based, or imidazole-based. More specifically, dicyandiamide-based curing agents may be included. Specifically, the curing catalyst may include an imidazole-based curing catalyst.

[0036] The bonding composition for an electromagnetic steel sheet of the present invention may further contain 0.10 to 1.00 parts by weight of a coupling agent with respect to 100 parts by weight of the polyurethane resin. Specifically, it may further contain 0.40 to 0.60 parts by weight of the coupling agent. When the amount of the crosslinking agent contained is excessively small, the effect of strengthening the interfacial adhesion between the electromagnetic steel sheet and the fusion layer cannot be sufficiently obtained. When the amount of the crosslinking agent contained is excessively large, precipitates may be generated in the adhesive coating composition due to the reaction between the crosslinking agents. The bonding composition for an electromagnetic steel sheet of the present invention may further contain 0.50 to 2.50 parts by weight of a curing agent with respect to 100 parts by weight of the polyurethane resin. Specifically, it may further contain 0.90 to 1.10 parts by weight of the curing agent. The curing agent serves to adjust the reactivity of the surface of the adhesive coating layer. When the amount of the curing agent contained is excessively small, the curing reaction of the fusion layer may decrease, and there may occur a problem that the adhesiveness (stickiness) of the surface of the fusion layer is poor. Conversely, when the amount of the curing agent added is excessively large, the fastening force after low-temperature fusion is poor.

[0037] The bonding composition for an electromagnetic steel sheet of the present invention may further contain 0.05 to 0.50 parts by weight of a wetting agent with respect to 100 parts by weight of the polyurethane resin. Specifically, it may further contain 0.09 to 0.11 parts by weight of the wetting agent. The bonding composition for an electromagnetic steel sheet of the present invention may further contain 0.10 to 1.00 parts by weight of a curing catalyst with respect to 100 parts by weight of the polyurethane resin. Specifically, it may further contain 0.40 to 0.60 parts by weight of the curing catalyst. The electromagnetic steel sheet of the present invention includes an electromagnetic steel sheet substrate; and a bonding coating layer located on the electromagnetic steel sheet substrate, the bonding coating layer includes an adhesive resin and a bonding additive, the adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol, and the diisocyanate monomer may include an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer. Specific descriptions such as the mixing ratio of the diisocyanate monomer overlap with those of the bonding composition for the electromagnetic steel sheet described above, so they are omitted.

[0038] The laminate of the present invention includes a plurality of electromagnetic steel sheets; and a fusion layer located between the plurality of electromagnetic steel sheets; the fusion layer includes an adhesive resin and a bonding additive, the adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol, and the diisocyanate monomer may include an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer. Specific descriptions such as the mixing ratio of the diisocyanate monomer are omitted because they overlap with the bonding composition for electromagnetic steel sheets described above. The thickness of the fusion layer of the electromagnetic steel sheet laminate can be 0.1 to 10 μm. If the thickness of the fusion layer is too thin, the adhesive force may decrease rapidly, and if it is too thick, problems due to adhesiveness may occur after coating winding. Specifically, the thickness of the fusion layer can be 2 to 7 μm. More specifically, it can be 5 to 7 μm. A coupling agent, a wetting agent, a curing catalyst, a curing agent, etc. may remain in the fusion layer of the electromagnetic steel sheet laminate.

[0039] The method for manufacturing the electromagnetic steel sheet laminate of the present invention may include the steps of: applying an adhesive coating composition to one or both surfaces of an electromagnetic steel sheet and then curing it to form an adhesive coating layer; and laminating and thermally fusing a plurality of electromagnetic steel sheets on which the adhesive coating layer is formed to form a fusion layer. Hereinafter, each step will be described in detail. First, prepare an adhesive coating composition. Since the adhesive coating composition has been described above, duplicate descriptions are omitted. Next, after coating the adhesive coating composition on the surface of the electromagnetic steel sheet, cure it to form an adhesive coating layer. This step is performed in a temperature range of 150 to 250 °C based on the plate temperature for curing the adhesive coating composition. A plurality of electromagnetic steel sheets with a coating layer formed thereon are laminated and thermally fused to form a fused layer 20. During the thermal fusion step, the polymer components in the adhesive coating layer are thermally fused to form the fused layer. The thermal fusion step is carried out under thermal fusion 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. The above conditions may be satisfied independently, or two or more conditions may be satisfied simultaneously. By adjusting the temperature, pressure, and time conditions in the thermal fusion step in this way, it is possible to achieve dense thermal fusion between the electromagnetic steel sheets without gaps or organic phases.

[0040] Hereinafter, preferred examples and comparative examples of the present invention will be described. However, the following examples are only a preferred example of the present invention, and the present invention is not limited to the following examples. Example Anisotropic electromagnetic steel sheets (50 × 50 mm, 0.35 mm t) were prepared as test pieces. An adhesive coating solution was applied to the upper and lower parts of the prepared test pieces at a constant thickness using a bar coater and a roll coater, respectively, cured at 150 to 200 °C for 20 seconds based on the plate temperature, and then slowly cooled in air to form an adhesive coating layer. As the adhesive coating solution, the monomers containing isocyanate were composed of a total of two types, namely one type of aliphatic isocyanate monomer and one type of aromatic isocyanate monomer, and the ratio was varied to react with polyol to obtain a polyurethane-containing solution. As the polyol, PPG (Poly(Propylene Glycol)) with a molecular weight of 425 g / mol was used. The composition of the adhesive coating solution other than the obtained polyurethane resin contained 0.5 parts by weight of a silane coupling agent, 0.1 parts by weight of a silicone-based wetting agent, 1 part by weight of a dicyandiamide-based curing agent, and 0.5 parts by weight of an imidazole-based curing catalyst as additives based on 100 parts by weight of the polyurethane resin. The formulation by type of isocyanate monomer used and the content ratio of polyol are as shown in Table 1 below, and the glass transition temperature, tensile strength, and elongation rate, which are the physical properties of the adhesive coating solution containing the produced polyurethane, were measured and shown in Table 1. The content of the isocyanate monomer and the content of the polyol in Table 1 were prepared based on 100% by weight of the polyurethane.

[0041] After laminating electromagnetic steel sheets coated with the adhesive coating layer at a height of 20 mm, they were pressed with a force of 0.5 MPa and heat-sealed at 160 °C for 10 minutes. The thickness of the fused layer after heat-sealing was about 3 μm. The heat-sealed fused bodies were evaluated by type of solution. As evaluation items, the peel adhesion strength (T-peel, N / mm) and the ATF resistance property were evaluated and shown in Table 1 below. The respective measurement methods are as follows.

[0042] Maximum tensile strength and elongation rate: In order to measure the mechanical physical properties of the synthesized polyurethane polymer, it was poured onto release paper and applied with a uniform thickness using an applicator, and then dried in a 100 °C vacuum oven for 24 hours to produce a dried film. The maximum tensile strength and elongation rate of the film were measured at a speed of 50 mm / min using a universal testing machine in accordance with ASTM D-1708 standard. Peel adhesion strength (T-peel, N / mm): The specifications of the test piece for peel method (T-Peeloff) measurement were prepared according to ISO11339. After bonding two 25×200 mm test pieces with an area of 25×150 mm 2 and bending the unbonded part by 90 degrees to produce a T-shaped tensile test piece. After fixing the test piece produced by the peel method (T-Peeloff) to the upper / lower jig (JIG) with a constant force, it was measured using a device that measures the tensile force of the laminated sample while pulling at a constant speed. At this time, in the case of the shear method, the measured value was the point where the interface with the minimum bonding force among the interfaces of the laminated sample dropped off. After maintaining the temperature of the test piece at 60 °C with a heating device, the adhesion force was measured. Evaluation method for ATF resistance: When a drive motor is used in an automobile, it rotates at high speed for a long time and generates a lot of heat. To cool this, ATF (Automotive Transmission Fluid, automotive transmission oil) is used. Therefore, in order to ensure the adhesion reliability during long-term use, it is important that the adhesive strength of the laminated coil is maintained while being impregnated with ATF. Accordingly, the ATF resistance was evaluated. The manufactured laminated coil was impregnated in ATF at a temperature of 150°C for 500 hours, and then the shear adhesive strength was tested.

[0043] The shear adhesive strength for measuring the ATF resistance was measured by the shear method (Shear Strength). The specifications of the test piece for shear method measurement were manufactured according to ISO4587. Two 25×100mm test pieces were adhered with an area of 12.5×25mm 2 and heat-sealed under the above conditions to produce a shear method test piece. After fixing the test piece produced by the shear method to the upper / lower jig (JIG) with a certain force, it was measured using a device that measures the tensile force of the laminated sample while pulling at a certain speed. At this time, in the case of the shear method, the measured value was the point where the interface with the minimum joining force among the interfaces of the laminated sample dropped off.

[0044]

Table 1

[0045] From the results in Table 1 above, in the case of Examples 1 and 2 where the blending weight ratio of MDI, an aromatic isocyanate monomer, and HDI, an aliphatic isocyanate monomer, was appropriately controlled, both the tensile strength and elongation rate were controlled within an appropriate range, and the peel strength (T-peel) was all 1.5 N / mm or more, showing excellent performance, and it was confirmed that the ATF resistance was also excellent. On the other hand, in the case of Comparative Example 1 containing a large amount of HDI, the elongation rate was excellent, but the tensile strength was low, and it was confirmed that the ATF resistance was also inferior. Also, in the case of Comparative Example 2 using only 2,4'-MDI, the tensile strength was excellent, but the elongation rate was inferior, and the peel strength was also inferior.

[0046] The present invention is not limited to the above embodiments and can be manufactured in various different forms. Those with ordinary knowledge in the technical field to which the present invention pertains can understand that it can be implemented in other specific forms without changing the technical idea and essential features of the present invention. Therefore, it must be understood that the above-described embodiment is illustrative in all respects and not restrictive.

Claims

1. comprising an adhesive resin and a bonding additive, wherein the adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol, the diisocyanate monomer includes an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer, the diisocyanate monomer contains 50 parts by weight or less of the aliphatic diisocyanate monomer with respect to 100 parts by weight in total of the diisocyanate monomer, the aromatic diisocyanate monomer is a monomer represented by the following Chemical Formula 1, Chemical Formula 2, or a combination thereof, the aliphatic diisocyanate monomer is a monomer represented by the following Chemical Formula 3, and the polyol is polypropylene glycol, characterized in that it is a bonding composition for an electromagnetic steel sheet. [Chemical Formula 1] [Chemical Formula 2] In the Chemical Formula 1, R １ to R １０ are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, or an isocyanate group, R １ ~R ５ Any one of them is isocyanate, and R ６ ~R １０ Any one of them is isocyanate, L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group, n is any integer from 1 to 10, In the Chemical Formula 2, R １１ to R １６ are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C5-C20 heteroaryl group, an isocyanate group or a substituted or unsubstituted C1-C10 alkyl isocyanate group, R １１ to R １６ at least two of which are isocyanate or substituted or unsubstituted C1-C10 alkyl isocyanate, [Chemical Formula 3] In the Chemical Formula 3, R is a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C3-C12 cycloalkyl group.

2. The bonding composition for an electromagnetic steel sheet according to Claim 1, wherein the aromatic diisocyanate monomer is one or more selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, p-phenylene diisocyanate, 2,2'-methylenediphenyl diisocyanate, 2,4'-methylenediphenyl diisocyanate, 4,4'-methylenediphenyl diisocyanate, and m-xylene diisocyanate.

3. The aliphatic diisocyanate monomer is at least one selected from the group consisting of hexamethylene diisocyanate (HDI), 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hydrogenated xylene diisocyanate, and the bonding composition for an electromagnetic steel sheet according to claim 1 is characterized in that.

4. The bonding composition for an electromagnetic steel sheet has a glass transition temperature (Tg) of more than -70°C and less than -10°C, a tensile strength of more than 40 MPa and less than 120 MPa, and an elongation rate of more than 100% and less than 800%, and the bonding composition for an electromagnetic steel sheet according to claim 1 is characterized in that.

5. An electromagnetic steel sheet substrate and including a bonding coating layer located on the electromagnetic steel sheet substrate, the bonding coating layer includes an adhesive resin and a bonding additive, the adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol, the diisocyanate monomer includes an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer, the diisocyanate monomer contains 50 parts by weight or less of the aliphatic diisocyanate monomer based on 100 parts by weight of the total diisocyanate monomer, the aromatic diisocyanate monomer is a monomer represented by the following Chemical Formula 1, Chemical Formula 2, or a combination thereof, the aliphatic diisocyanate monomer is a monomer represented by the following Chemical Formula 3, the polyol is polypropylene glycol, and the electromagnetic steel sheet is characterized in that. [Chemical Formula 1] [Chemical Formula 2] In Chemical Formula 1, R １ to R １０ are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, or an isocyanate group, R １ ~R ５ Any one of them is an isocyanate, and R ６ ~R １０ Any one of them is an isocyanate, L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group, n is any integer from 1 to 10, In Chemical Formula 2, R １１ ~R １６ are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C5-C20 heteroaryl group, an isocyanate group or a substituted or unsubstituted C1-C10 alkyl isocyanate group, R １１ ~R １６ at least two of which are isocyanates or substituted or unsubstituted C1-C10 alkyl isocyanates, [Chemical Formula 3] In Chemical Formula 3, R is a substituted or unsubstituted C1-C10 alkyl group or a substituted or unsubstituted C3-C12 cycloalkyl group.

6. A plurality of electromagnetic steel sheets and It includes a fusion layer located between the plurality of electromagnetic steel sheets, The fusion layer includes an adhesive resin and a bonding additive, The adhesive resin is a polyurethane formed by reacting a diisocyanate monomer and a polyol, The diisocyanate monomer includes an aromatic diisocyanate monomer and an aliphatic diisocyanate monomer, The diisocyanate monomer contains 50 parts by weight or less of the aliphatic diisocyanate monomer with respect to 100 parts by weight in total of the diisocyanate monomer, The aromatic diisocyanate monomer is a monomer represented by the following Chemical Formula 1, Chemical Formula 2, or a combination thereof, The aliphatic diisocyanate monomer is a monomer represented by the following Chemical Formula 3, The electromagnetic steel sheet laminate, characterized in that the polyol is polypropylene glycol. [Chemical Formula 1] [Chemical Formula 2] In the Chemical Formula 1, R １ ~R １０ are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C5-C20 heteroaryl group, or an isocyanate group, R １ ~R ５ Any one of them is an isocyanate, and R ６ ~R １０ Any one of them is an isocyanate, L is a substituted or unsubstituted C1-C10 alkylene group, a substituted or unsubstituted C2-C10 alkynylene group, a substituted or unsubstituted C6-C20 arylene group, or a substituted or unsubstituted C5-C20 heteroarylene group, n is any integer from 1 to 10, In the Chemical Formula 2, R １１ to R １６ are each independently hydrogen, deuterium, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted C5-C20 heteroaryl group, an isocyanate group or a substituted or unsubstituted C1-C10 alkyl isocyanate group, R １１ to R １６ At least two of them are isocyanate or substituted or unsubstituted C1-C10 alkyl isocyanate. [Chemical Formula 3] In the Chemical Formula 3, R is a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C3-C12 cycloalkyl group.

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