Graphene-coated steel sheet

Abstract

A graphene-coated steel sheet according to an embodiment comprises: a plated steel sheet; and a graphene coating layer disposed on the plated steel sheet and containing graphene, wherein the graphene is contained in a content of 0.1 to 30 wt% relative to the total weight of the graphene coating layer, and the average distribution area fraction of graphene particles per unit area (0.1 mm Х 0.1 mm) of the graphene coating layer may be 10 or more.

Description

graphene coated steel sheet

[0001] The present invention relates to a graphene coated steel sheet.

[0002] Graphene is a two-dimensional (2D) crystal structure material with a thickness of a single atomic layer in which carbon atoms are arranged in a specific arrangement, and the carbon atoms are connected in a hexagonal shape.

[0003] Graphene boasts a tensile strength 311 times greater than steel, electron mobility 1,000 times greater than silicon, thermal conductivity over 10 times greater than copper, transparency that allows 98% of light to pass through, and the ability to maintain its properties even when bent or stretched. These properties make it widely applicable in nanomaterials, inks, barrier materials, heat-dissipating materials, ultra-light materials, energy electrode materials, next-generation semiconductors, and transparent electrodes.

[0004] However, in order to coat graphene using a solution process, the graphene must be uniformly distributed within the coating layer to achieve the desired properties.

[0005] One embodiment of the present invention can provide a graphene-coated steel sheet having excellent formability and heat dissipation properties.

[0006] One embodiment of the present invention can provide a graphene-coated steel sheet having excellent heat dissipation properties even when including another coating layer.

[0007] One embodiment of the present invention can provide a graphene-coated steel sheet having excellent heat dissipation properties even when used in combination with other pigments.

[0008] A graphene-coated steel sheet, which is an embodiment of the present invention, comprises: a plated steel sheet; and a graphene coating layer disposed on the plated steel sheet and including graphene, wherein the graphene is included in an amount of 0.1 to 30 wt% based on the total weight of the graphene coating layer, and an average distribution area ratio of graphene particles per unit area (0.1 mm Х 0.1 mm) of the graphene coating layer is 10% or more.

[0009] The above-mentioned plated steel sheet may be at least one selected from the group consisting of a zinc-plated steel sheet, a zinc-based alloy-plated steel sheet, an aluminum-plated steel sheet, an aluminum-based alloy-plated steel sheet, a cold-rolled steel sheet, and a hot-rolled steel sheet.

[0010] The above graphene coating layer may include a binder.

[0011] The above binder may be two or more types of acrylic resin.

[0012] The above two or more types of acrylic resins may be two or more types selected from the group consisting of a copolymer of ethylene acrylic acid (EAA) and polyethylene (PE), a copolymer of ethylene acrylic acid (EAA) and polyurethane (PU), polymethyl methacrylate, polyacrylonitrile, chlorhexyl acrylate, glycidyl acrylate, and hydroxy alkyl acrylate.

[0013] The above binder may further include at least one selected from the group consisting of epoxy resin, urethane resin, fluorine resin, polyester resin, polyethylene resin, and vinyl chloride resin.

[0014] The above epoxy resin may be at least one selected from the group consisting of bisphenol A type resin, bisphenol F type resin, novolac resin, acrylic modified epoxy resin, cycloaliphatic resin, and glycidyl amine type resin.

[0015] The above urethane resin may be at least one selected from the group consisting of polyurethane, acrylic polyol, and polyisocyanate prepared from isophorene diisocyanate, adipic acid, and polyhydric alcohol.

[0016] The above fluorine-based resin may be at least one selected from the group consisting of a fluorine-based urethane resin obtained using a perfluoroalkyl alcohol, a perfluorinated acrylic polyol, a fluorinated polyolefin-based polyol, or a mixture thereof, or polymethyl-α-fluoroacrylate, block poly-α-fluoroacrylate, polyethyl-α-fluoroacrylate, and polyfluoroalkylacrylate.

[0017] The above graphene coating layer may further include an additive.

[0018] The above additive may be at least one selected from the group consisting of titanium compounds, ammonium phosphate salts, vanadium compounds, organophosphates, amine phosphate salts, organic acids, leveling agents, wetting agents, curing agents, and defoaming agents.

[0019] The above graphene coated steel sheet can satisfy the following equation (1):

[0020] [Formula (1)]

[0021] C G ·t ≥ 0.71

[0022] (In the above equation (1), C G is the graphene content (weight %) included in the graphene coating layer, and t is the coating layer thickness (㎛).

[0023] The above graphene coated steel sheet can satisfy the following equation (2):

[0024] [Formula (2)]

[0025] C G 1 / 6 ·t ≤ 32

[0026] (In the above equation (2), C G is the graphene content (weight %) included in the graphene coating layer, and t is the coating layer thickness (㎛).

[0027] The thickness of the above graphene coating layer may be 0.1 to 30 μm.

[0028] One embodiment of the present invention can provide a graphene-coated steel sheet having excellent formability and heat dissipation properties.

[0029] One embodiment of the present invention can provide a graphene-coated steel sheet having excellent heat dissipation properties even when including another coating layer.

[0030] One embodiment of the present invention can provide a graphene-coated steel sheet having excellent heat dissipation properties even when used in combination with other pigments.

[0031] Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0032] In addition, the embodiments of the present invention are provided to more completely explain the present invention to a person having average knowledge in the relevant technical field.

[0033] The shape and size of elements in the drawing may be exaggerated for clearer explanation.

[0034] In describing the embodiments of the present invention, if a detailed description of a known technology related to the present invention is judged to unnecessarily obscure the gist of the present invention, such detailed description will be omitted. In addition, the terms described below are terms defined in consideration of their functions in the present invention, and these may vary depending on the intention or custom of the user or operator. Therefore, the definitions should be made based on the contents throughout this specification. The terminology used in the detailed description is only for the purpose of describing the embodiments of the present invention and should in no way be limiting. Unless clearly defined otherwise, expressions in the singular form include plural meanings.

[0035] In this description, expressions such as "including" or "having" are intended to indicate certain features, numbers, steps, operations, elements, portions or combinations thereof, and should not be construed to exclude the presence or possibility of one or more other features, numbers, steps, operations, elements, portions or combinations thereof other than those described.

[0036] Unless otherwise specified in the specification of the present invention, the % unit means weight %.

[0037] Additionally, throughout the specification, when we say that a part is 'connected' to another part, this includes not only cases where it is 'directly connected', but also cases where it is 'indirectly connected' with other elements in between.

[0038] Below, the present invention will be described in detail through each embodiment or example of the present invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may be combined with other embodiments or examples. Therefore, the citation of a claim in the patent claims is only an example of an embodiment, and the technical concept of the present invention should not be interpreted solely as a combination with the cited claim, and combinations with various claims also fall within the scope of the technical concept of the present invention.

[0039] The terms used herein are for the purpose of describing the invention and are not intended to limit the invention. Furthermore, singular forms used herein also include plural forms, unless the relevant definition clearly indicates a contrary meaning.

[0040] The meaning of “comprising” as used in the present invention is to specify a configuration and not to exclude the presence or addition of other configurations.

[0041] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention pertains. Terms defined in the dictionary are to be interpreted to have meanings consistent with the relevant technical literature and the present disclosure.

[0042] Hereinafter, a graphene-coated steel sheet according to one embodiment of the present invention will be described in detail.

[0043] As a result of experiments conducted by the inventors with different graphene concentrations and coating thicknesses within the coating layer, it was confirmed that the heat dissipation characteristics have a certain correlation with the graphene area ratio, and it was found that the graphene area ratio is determined by the graphene concentration and coating thickness within the coating layer.

[0044] Accordingly, a graphene-coated steel sheet according to one embodiment of the present invention comprises: a plated steel sheet; and a graphene coating layer disposed on the plated steel sheet and including graphene, wherein the graphene is included in an amount of 0.1 to 30 wt% based on the total weight of the graphene coating layer, and an average distribution area ratio of graphene particles per unit area of ​​the graphene coating layer may be 10% or more.

[0045] In this specification, the average graphene distribution area ratio is defined as the area ratio occupied by graphene in the total photographic area measured using an image analyzer at 500 to 1,000x magnification using an optical microscope. In addition, the average graphene distribution area ratio is based on the average value of five photographs measured.

[0046] In the present invention, the type of the plated steel sheet is not particularly limited, but may be, for example, a zinc-plated steel sheet, a zinc-based alloy-plated steel sheet, an aluminum-plated steel sheet, an aluminum-based alloy-plated steel sheet, a cold-rolled steel sheet, and a hot-rolled steel sheet.

[0047] The thickness of the above graphene coating layer is not particularly limited, but may be, for example, 0.1 to 30 μm. If the thickness of the coating layer is less than 0.1 μm, the surface treatment solution composition is thinly applied to the rough acid portion of the surface of the plated steel sheet, which causes a problem of reduced corrosion resistance. On the other hand, if the thickness exceeds 30 μm, the film layer (coating layer) is formed thickly, which deteriorates processability and increases the cost of solution treatment, which is economically disadvantageous.

[0048] Here, the above thickness refers to the thickness after drying.

[0049] Accordingly, a graphene-coated steel sheet of one embodiment may include a graphene coating layer disposed on the plated steel sheet and containing graphene. The plated steel sheet on which the graphene coating layer is disposed may have excellent corrosion resistance, processability, adhesion, and heat dissipation properties.

[0050] The above graphene coating layer may have an average distribution area ratio of graphene particles per unit area (0.1 mm × 0.1 mm) of the graphene coating layer of 10% or more, specifically 20% or more, more specifically 30% or more, even more specifically 40% or more, and even more specifically 50% or more. If the average distribution area ratio of the graphene particles is less than 10%, the graphene content included in the graphene coating layer may be low, resulting in poor heat dissipation.

[0051] The type of the above graphene particles is not particularly limited.

[0052] The graphene may be included in an amount of 0.1 to 30 wt% based on the total weight of the graphene coating layer, specifically 0.1 to 10 wt%, and more specifically 0.1 to 20 wt%. If the graphene is included in an amount of less than 0.1 wt% based on the total weight of the graphene coating layer, heat dissipation properties may be poor, and if it exceeds 30 wt%, dispersion stability may be poor.

[0053] The size of the above graphene particles may refer to the lateral size of the graphene, and the size is not particularly limited, but may be, for example, 1 to 5 μm.

[0054] The above graphene coating layer may include a binder. The binder can improve the dispersion stability of graphene and provide excellent ductility and processability when coating a steel plate.

[0055] The above binder may be a binder comprising two or more types of acrylic resins. A solution composition containing the above binder may have excellent dispersion stability with graphene, and may have excellent ductility and processability when coating a steel plate.

[0056] The above two or more types of acrylic resins may be two or more types selected from the group consisting of a copolymer of ethylene acrylic acid (EAA) and polyethylene (PE), a copolymer of ethylene acrylic acid (EAA) and polyurethane (PU), polymethyl methacrylate, polyacrylonitrile, chlorhexyl acrylate, glycidyl acrylate, hydroxy alkyl acrylate, etc., and specifically, may be a copolymer of ethylene acrylic acid (EAA) and polyethylene (PE) and a copolymer of ethylene acrylic acid (EAA) and polyurethane (PU).

[0057] When the binder of the above graphene coating layer includes two types of acrylic resins, the content ratio of each resin may be 1:1 to 1:6, and specifically, 1:3 to 1:5. When the binder includes two types of acrylic resins in the above content ratio, corrosion resistance, processability, and coating adhesion may be improved, and the physical properties of the coating layer may be improved compared to when it includes one type of acrylic resin.

[0058] The above binder may further include, but is not particularly limited to, at least one selected from the group consisting of, for example, epoxy resin, urethane resin, fluorine resin, polyester resin, polyethylene resin, vinyl chloride resin, etc.

[0059] The above epoxy resin may be at least one selected from the group consisting of bisphenol A type resin, bisphenol F type resin, novolac resin, acrylic modified epoxy resin, cycloaliphatic resin, glycidyl amine type resin, etc.

[0060] The above urethane resin may be at least one selected from the group consisting of polyurethane, acrylic polyol, polyisocyanate, etc. prepared from isophorene diisocyanate, adipic acid, and polyhydric alcohol.

[0061] The above fluorine-based resin may be at least one selected from the group consisting of a fluorine-based urethane resin obtained using a perfluoroalkyl alcohol, a perfluorinated acrylic polyol, a fluorinated polyolefin-based polyol, or a mixture thereof, or polymethyl-α-fluoroacrylate, block poly-α-fluoroacrylate, polyethyl-α-fluoroacrylate, polyfluoroalkylacrylate, etc.

[0062] The above graphene coating layer may contain 55 to 90 wt% of a binder, and specifically 60 to 90 wt%. If the binder content is less than 55 wt%, corrosion resistance, processability, and coating adhesion may be poor, and the dispersion stability of graphene may be poor. If the binder content is more than 90 wt%, heat dissipation may be poor.

[0063] The above graphene coating layer is not particularly limited, but may further include, for example, additives.

[0064] Among the above additives, the property improver can improve the adhesion between the steel sheet and the coating layer and can improve corrosion resistance. The property improver may be at least one selected from the group consisting of titanium compounds, ammonium phosphate salts, vanadium compounds, organic phosphoric acids, amine phosphate salts, and organic acids, and specifically, may be at least one selected from the group consisting of titanium compounds and ammonium phosphate salts.

[0065] The above graphene coating layer may contain 5 to 40 wt% of a property-improving agent among additives. If the content of the property-improving agent included in the graphene-coated steel sheet is less than 5 wt%, the properties of the coated steel sheet may deteriorate, and if it exceeds 40 wt%, corrosion resistance, adhesion, and processability may deteriorate.

[0066] The above additive may be at least one selected from the group consisting of a leveling agent, a wetting agent, a curing agent, and an anti-foaming agent.

[0067] The above leveling agent may be at least one selected from the group consisting of silicone-modified polyacrylate, polyacrylate, fluorine-modified polyacrylate, polysiloxane, etc.

[0068] The above wetting agent serves to enable the graphene-coated steel sheet to adhere well to the steel sheet, and may be at least one selected from the group consisting of polyether-modified polyalkylsiloxane, aralkyl-modified polyalkylsiloxane, polyether-modified siloxane, polymeric fluorine-based surfactant, alcohol alkoxylate (non-silicone type), etc.

[0069] The above-mentioned hardener serves to form a dried film by coating the graphene-coated steel sheet, and may be at least one selected from the group consisting of amine-based, amide-based, silane coupling agent, carbodilite-based, isocyanate-based, aziridine-based, epoxy-based, crosslinker, etc.

[0070] The above-mentioned antifoaming agent has the function of reducing the generation of bubbles when stirring and roll-coating the graphene-coated steel sheet, and may be at least one selected from the group consisting of silicone-based, mineral oil-based, and polymer-based (silicon- and mineral oil-free types).

[0071] The above graphene coating layer is not particularly limited, but may include, for example, 1 to 5 wt% of an additive.

[0072] The composition for a graphene-coated steel sheet of one embodiment may further comprise a residual solvent. The solvent may be at least one selected from the group consisting of water, 1-Ethyl-2-Pyrrolidinone (NEP), and Dimethyl Sulfoxide (DMSO).

[0073] The above graphene coated steel sheet can satisfy the following equation (1).

[0074] [Formula (1)]

[0075] C G ·t ≥ 0. 71

[0076] (In the above equation (1), C Gis the graphene content (weight %) included in the graphene coating layer, and t is the coating layer thickness (㎛).

[0077] In the above equation (1), C G ·If the t value is less than 0.71, the heat dissipation performance of the graphene-coated steel sheet may be inferior.

[0078] In addition, the graphene-coated steel sheet can satisfy the following equation (2).

[0079] [Formula (2)]

[0080] C G 1 / 6 ·t ≤ 32

[0081] (In the above equation (2), C G is the graphene content (weight %) included in the graphene coating layer, and t is the coating layer thickness (㎛).

[0082] The graphene steel coating layer satisfying the condition of the above formula (2) may have excellent dispersion stability and thus excellent formability. On the other hand, in the above formula (2), C G 1 / 6 ·If the t value exceeds 32, the dispersion stability of graphene is poor and cracks may occur.

[0083] According to one embodiment of the present invention, even if another coating layer is included in addition to the graphene coating layer, excellent heat dissipation properties can still be achieved.

[0084] In addition, according to one embodiment of the present invention, even if other materials such as pigments are further included in the graphene coating layer, the heat dissipation properties can still be excellent.

[0085] Furthermore, another embodiment of the present invention describes a method for manufacturing a graphene coated steel sheet.

[0086] More specifically, it may include a step of providing a plated steel sheet having a plated layer formed on at least one surface; a step of coating the above-described solution composition on the plated layer; and a step of drying the coated steel sheet.

[0087] The above solution composition can be prepared by adding graphene, binder, property improver, and additives to a solvent according to their respective contents, and then stirring.

[0088] When applying the composition of the present invention in a solution state to the steel plate, a commonly used coating method can be applied, and thus there is no particular limitation.

[0089] For example, the coating process may be performed by selecting one method from among bar coating, roll coating, spraying, dipping, spray squeezing, and dipping squeezing, but is not particularly limited thereto.

[0090] The process of drying the steel plate coated with the above composition can be performed at a temperature range of 40 to 280°C based on the final temperature reached (PMT) of the material (steel plate).

[0091] If the final temperature of the above material is below 40℃, the formation of a solid film structure may be insufficient, which may result in poor corrosion resistance and blackening resistance. On the other hand, if the temperature exceeds 280℃, the hardness of the film may increase excessively, resulting in poor corrosion resistance of the processed area and poor surface quality, such as yellowing due to excessive heat.

[0092] The steel plate that has undergone the above drying process can have a coating layer with a thickness of 0.1 to 30 μm after drying.

[0093] In the present invention, the means for performing the drying process is not particularly limited, but it is disclosed that equipment such as an induction oven or a hot air dryer can be used, and the conditions of these equipment can be based on normal conditions.

[0094]

[0095] Example

[0096] Hereinafter, the present invention will be described in more detail through examples. However, the description of these examples is merely intended to illustrate the implementation of the present invention and is not intended to limit the present invention. This is because the scope of the present invention is determined by the matters set forth in the claims and matters reasonably inferred therefrom.

[0097]

[0098] 1. Experimental Example 1 (Heat Dissipation Performance Experiment)

[0099] (1) Manufacturing of graphene-coated steel sheets

[0100] A graphene coating solution was prepared by stirring graphene with a binder and additives in the weights shown in Table 1 below. In the graphene coating solution, the content excluding graphene was added at a weight ratio of 8:2 to the binder and additives.

[0101] The prepared graphene coating solution was applied and dried on a 0.5 to 2.0 t hot-dip galvanized steel plate to prepare a graphene-coated steel plate having a coating thickness as shown in Table 1 below.

[0102] As a binder, a copolymer resin containing about 2 wt% of TMOS (trimethoxysilane) in the side chain of a solvent-free type EAA (Ethylene Acrylic Acide) and PE (Polyethylene) copolymer resin and two types of solvent-free type EAA and PU copolymer resins are mixed at a weight ratio of 4:1.

[0103] Titanium diethylene glycol propylene glycol triethanolamine complexes were used as additives.

[0104] (2) Heat dissipation test

[0105] In an environment where the ambient temperature was maintained at 23 to 25°C, a hole was drilled in the upper part of an insulating box with a built-in heat source, a coated specimen measuring 200 mm x 200 mm was placed, the specimen was placed in place, and the area around the specimen was sealed again.

[0106] The above specimen was powered on and maintained for more than two hours, and temperature changes were measured until the temperature inside the steel plate and insulation box remained constant. Once the temperature remained constant, the temperature difference between the inside and outside of the box was measured, and this is shown in Table 1 below.

[0107] In addition, when the equilibrium temperature difference of Comparative Example 1 is T1 and the equilibrium temperature difference of each coated steel plate is T2, the value calculated as (T1-T2) / T1 x 100% is used as the heat dissipation effect and is shown in Table 1 below.

[0108] (3) Measurement of graphene area

[0109] Ten photographs were taken at 500x magnification using an optical microscope, and the average value of the proportion of graphene in the entire photograph area was measured using an image analyzer, which is shown in Table 1 below.

[0110] Additionally, the values ​​measured according to the following equation (1) are shown in Table 1 below.

[0111] [Formula (1)]

[0112] C G ·t ≥ 0. 71

[0113] (In the above equation (1), C G is the graphene content (weight %) included in the graphene coating layer, and t is the coating layer thickness (㎛).

[0114] Graphene (weight %)Coating layer thickness (㎛)Graphene area ratio (%)C G·tHeat dissipation temperature difference (℃)Heat dissipation effect (%)Comparative example 100.950040.10Comparative example 20.20.4810.09640.060.1Comparative example 30.21.0130.20240.020.21Comparative example 40.21.9760.39439.920.25Example 10.23.55100.7139.620.46Example 20.28.16191.63239.220.59Example 30.210.43272.08638.940.5Example 40.214.65352.9338.071.2Comparative example 50.50.530.25401.36Comparative Example 60.51.0370.51539.91.15Example 50.52.06151.0339.641.18Example 60.54.04232.0238.82.19Example 70.58.28444.1437.033.26Example 80.510.3565.1536.353.12Example 90.514.87727.43534.783.24Comparative Example 710.5170.5139.862.89Example 1011.04141.0439.634.15Example 1111.94261.9438.795.06 Example 1214.17464.1737.117.3 Example 1318.34638.3433.947.66 Example 14110.427810.4232.687.45 Example 15114.919014.9132.8410.9 Example 1620.513139.559.35 Example 1720.99261.9838.859.62 Example 1822.05454.137.1713.26 Example 1924.18748.3633.4115.35 Example 2027.719715.4231.8916.68Example 21210922032.4715.89Example 22214.559929.131.4516.16Example 2350.5282.538.4418.5Example 2451.03565.1536.2418.1Example 2551.94779.733.7320.48Example 2654.199820.9532.2319.02Example 2757.729638.631.9919.87Example 28510975031.4719.63Example 29514.439972.1531.5721.56 Example 30100.49544.935.7320.22 Example 31100.98709.833.6219.42Example 32102.029920.232.1321.53Example 33103.889438.832.3121.26Example 34107.719877.131.920.44Example 35109.529795.231.8620.54Example 361014.9999149.932.0420.09.

[0115]

[0116] Referring to Table 1 above, it can be confirmed that the steel plates of Examples 1 to 36 having a graphene area ratio of 10% or more have a heat dissipation effect.

[0117] However, it can be confirmed that the heat dissipation effect is minimal in comparisons 1 to 7 where the graphene area ratio is less than 10%.

[0118]

[0119] 2. Experimental Example 2 (Heat dissipation performance test on a plated steel sheet containing a multi-layer coating layer)

[0120] (1) Manufacturing of graphene-coated steel sheet including multi-layer coating layers

[0121] A graphene coating solution was prepared by mixing 2 wt% of graphene with 100 wt% of solid content, and the remaining 98 wt% of the binder and additive used in Experimental Example 1 in a ratio of 8:2.

[0122] A coating solution for topcoat was prepared without graphene, with a solid content of approximately 35 wt% using a polyester resin and a melamine-based curing agent in a 1:1 weight ratio.

[0123] A coating solution for undercoat was prepared without graphene, with a solid content of approximately 5 wt%, using a silane coupling agent and ammonium phosphate salt in a 1:1 weight ratio.

[0124] A lower coating solution, a graphene coating solution, and a top coating solution were sequentially applied to a hot-dip galvanized steel sheet having a thickness of 0.5 to 2.0 t, and dried to manufacture a graphene-coated steel sheet having a thickness of 5 µm and the thicknesses of the top and bottom coating layers as shown in Table 2 below.

[0125] (2) Heat dissipation test

[0126] The heat dissipation effect of each graphene-coated steel plate was measured using the same method as the heat dissipation experiment of Experimental Example 1 above, and the results are shown in Table 2.

[0127] Substrate thickness (㎛) Top surface thickness (㎛) Graphene area ratio (%) C G ·tHeat dissipation Equilibrium temperature difference (℃)Heat dissipation effect (%)Example 370.5-781033.6116.20Example 381-761033.5216.42Example 392-761033.3416.87Example 405-781033.6316.12Example 41-0.5801033.5016.14Example 42-1771034.5016.73Example 43-2741035.9817.90Example 44-5791039.7117.73

[0128] Referring to the above examples 37 to 44, it can be confirmed that the plated steel sheet including the graphene coating layer exhibits substantially the same heat dissipation effect even when the plated steel sheet includes a coating layer that does not include graphene on the upper or lower layer of the graphene coating layer.

[0129]

[0130] 3. Experimental Example 3 (Heat dissipation performance test on a plated steel sheet containing a coating layer containing pigment)

[0131] (1) Manufacturing of graphene-coated steel sheet including multi-layer coating layers

[0132] A graphene coating solution was prepared by mixing an inorganic pigment containing titanium dioxide and carbon black in a 1:1 weight ratio, graphene, the binder of Experimental Example 1, and the additive of Experimental Example 1 according to Table 3 below. The binder and additive were added in a weight ratio of 8:2, excluding the inorganic pigment and graphene, in the graphene coating solution.

[0133] Using the graphene coating solution prepared above, a graphene-coated steel sheet was prepared in the same manner as in Experimental Example 1.

[0134] (2) Heat dissipation test

[0135] The heat dissipation effect of each graphene-coated steel plate was measured using the same method as the heat dissipation experiment of Experimental Example 1 above, and the results are shown in Table 3.

[0136] Inorganic pigment (wt%) Graphene (wt%) Film thickness (㎛) Heat dissipation Equilibrium temperature difference (℃) Heat dissipation effect (%) Comparative example 8 102.114 0.17-0.18 Comparative example 9 202.104 0.20-0.24 Comparative example 105 01.984 0.02 0.19 Comparative example 111 001.844 0.04 0.14 Example 45 122.16 36.39 9.25 Example 46 222.09 37.28 7.03 Example 47 521.89 36.81 8.20 Example 48 1021.99 37.40 6.74

[0137] Referring to Table 3 above, it can be confirmed that the graphene-coated steel sheet layer containing pigment has excellent heat dissipation properties and that the content of the pigment does not significantly affect the heat dissipation properties. On the other hand, it can be confirmed that the plated steel sheet that does not contain graphene, even if it contains pigment, has poor heat dissipation properties.

Claims

1. Galvanized steel plate; and A graphene coating layer disposed on the above-mentioned galvanized steel plate and including graphene, The above graphene is included in an amount of 0.1 to 30 wt% based on the total weight of the graphene coating layer, A graphene-coated steel sheet, wherein the average distribution area ratio of graphene particles per unit area (0.1 mm Х 0.1 mm) of the graphene coating layer is 10% or more.

2. In paragraph 1, The above-mentioned coated steel sheet is a graphene-coated steel sheet, at least one selected from the group consisting of a zinc-coated steel sheet, a zinc-based alloy-coated steel sheet, an aluminum-coated steel sheet, an aluminum-based alloy-coated steel sheet, a cold-rolled steel sheet, and a hot-rolled steel sheet.

3. In paragraph 1, A graphene-coated steel sheet, wherein the graphene coating layer comprises a binder.

4. In paragraph 3, The above binder is a graphene-coated steel sheet comprising two or more types of acrylic resins.

5. In paragraph 3, A graphene-coated steel sheet, wherein the two or more types of acrylic resins are two or more types selected from the group consisting of a copolymer of ethylene acrylic acid (EAA) and polyethylene (PE), a copolymer of ethylene acrylic acid (EAA) and polyurethane (PU), polymethyl methacrylate, polyacrylonitrile, chlorhexyl acrylate, glycidyl acrylate, and hydroxy alkyl acrylate.

6. In paragraph 4, A graphene-coated steel sheet, wherein the binder further comprises at least one selected from the group consisting of epoxy resin, urethane resin, fluorine resin, polyester resin, polyethylene resin, and vinyl chloride resin.

7. In paragraph 6, A graphene-coated steel sheet, wherein the epoxy resin is at least one selected from the group consisting of bisphenol A type resin, bisphenol F type resin, novolac resin, acrylic modified epoxy resin, cycloaliphatic resin, and glycidyl amine type resin.

8. In paragraph 6, A graphene-coated steel sheet, wherein the urethane-based resin is at least one selected from the group consisting of polyurethane, acrylic polyol, and polyisocyanate manufactured from isophorene diisocyanate, adipic acid, and polyhydric alcohol.

9. In paragraph 6, A graphene-coated steel sheet, wherein the fluorine-based resin is at least one selected from the group consisting of a fluorine-based urethane resin obtained by using a perfluoroalkyl alcohol, a perfluorinated acrylic polyol, a fluorinated polyolefin-based polyol, or a mixture thereof, or polymethyl-α-fluoroacrylate, block poly-α-fluoroacrylate, polyethyl-α-fluoroacrylate, and polyfluoroalkylacrylate.

10. In paragraph 1, A graphene-coated steel sheet, wherein the graphene coating layer further comprises an additive.

11. In paragraph 10, A graphene-coated steel sheet, wherein the additive is at least one selected from the group consisting of titanium compounds, ammonium phosphate salts, vanadium compounds, organic phosphoric acids, amine phosphate salts, organic acids, leveling agents, wetting agents, hardeners, and defoaming agents.

12. In paragraph 1, The above graphene-coated steel sheet satisfies the following equation (1): [Formula (1)] C G ·t ≥ 0.71 (In the above equation (1), C G is the graphene content (weight %) included in the graphene coating layer, and t is the coating layer thickness (㎛).

13. In paragraph 1, The above graphene-coated steel sheet satisfies the following equation (2): [Formula (2)] C G 1 / 6 ·t ≤ 32 (In the above equation (2), C G is the graphene content (weight %) included in the graphene coating layer, and t is the coating layer thickness (㎛).

14. In paragraph 1, A graphene-coated steel sheet, wherein the thickness of the graphene coating layer is 0.1 to 30 μm.