Solution composition for graphene-coated steel sheets and plated steel sheets coated therewith

Abstract

One embodiment of the graphene-coated steel sheet solution composition may contain 0.1 to 30% by weight of graphene and 55 to 90% by weight of a main resin containing two or more acrylic resins, based on 100% by weight of solids.

Description

Technical Field

[0001] The present invention relates to a solution composition for graphene-coated steel sheets and a plated steel sheet coated therewith.

Background Art

[0002] Graphene is a substance having a two-dimensional (2D) crystal structure with a thickness of a single atomic layer in which carbon atoms are arranged in a specific sequence, and has a planar structure in which carbon atoms are connected in a hexagonal form.

[0003] Graphene has a tensile strength 311 times higher than that of steel, an electron mobility 1,000 times faster than that of silicon, a thermal conductivity more than 10 times superior to that of copper, is transparent enough to transmit 98% of light, and retains its properties even when bent or stretched. Due to such properties, it can be widely used in nanomaterials, inks, barrier materials, heat dissipation materials, ultra-lightweight materials, energy electrode materials, next-generation semiconductors, transparent electrodes and the like.

[0004] In order to coat such graphene on a base material easily and over a large area, a solution process is widely used. In the case of the solution process, a separate binder is required to ensure adhesion to the base material.

[0005] Therefore, it is a current situation that a binder having sufficient binding force while graphene is well dispersed must be separately selected, and in order to obtain a sufficient dispersion effect, a dispersant that does not adversely affect the physical properties of the coating composition must be appropriately selected.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One embodiment according to the present disclosure can provide a solution composition for graphene-coated steel sheets with excellent dispersion stability.

[0007] Other embodiments relating to this disclosure can provide plated steel sheets coated with graphene, which has excellent corrosion resistance and adhesion. [Means for solving the problem]

[0008] One embodiment of the graphene-coated steel sheet solution composition comprises 0.1 to 30% by weight of graphene and 55 to 90% by weight of a main resin containing two or more acrylic resins, based on 100% by weight of solids.

[0009] The two or more acrylic resins mentioned above may be two or more selected from the group consisting of copolymers of ethylene acrylic acid (EAA) and polyethylene (PE), copolymers of ethylene acrylic acid (EAA) and polyurethane (PU), polymethyl methacrylate, polyacrylonitrile, cyclohexyl acrylate, glycidyl acrylate, and hydroxyalkyl acrylate.

[0010] The main resin mentioned above may further include at least one selected from the group consisting of epoxy resins, urethane resins, fluororesins, polyester resins, polyethylene resins, and vinyl chloride resins.

[0011] The epoxy resin mentioned above may be at least one selected from the group consisting of bisphenol A type resins, bisphenol F type resins, novolac resins, acrylic-modified epoxy resins, alicyclic resins, and glycidylamine type resins.

[0012] The above-mentioned urethane resin may be at least one selected from the group consisting of polyurethanes produced from isophorone diisocyanate, adipic acid, and polyhydric alcohols, acrylic polyols, and polyisocyanates.

[0013] The above-mentioned fluororesin may be a fluorourethane resin obtained using a perfluoroalkyl alcohol, a perfluorolated acrylic polyol, a fluorinated polyolefin polyol, or a mixture thereof, or at least one selected from the group consisting of polymethyl-α-fluoroacrylate, blocked poly-α-fluoroacrylate, polyethyl-α-fluoroacrylate, and polyfluoroalkyl acrylate.

[0014] The above composition may further contain a property improver or other additive.

[0015] The above-mentioned property improver may be at least one selected from the group consisting of titanium compounds, ammonium phosphate salts, vanadium compounds, organic phosphoric acids, phosphate amine salts, and organic acids.

[0016] The above-mentioned property improver can be included in an amount of 5 to 40% by weight relative to 100% by weight of solids.

[0017] The above-mentioned other additives may be at least one selected from the group consisting of leveling agents, wetting agents, hardening agents, and defoaming agents.

[0018] The above-mentioned other additives may be included in an amount of 1 to 5% by weight relative to 100% by weight of solids.

[0019] The above composition may further contain a solvent, which may be at least one selected from the group consisting of water, NEP (1-Ethyl-2-Pyrrolidinone), and DMSO (Dimethyl Sulfoxide).

[0020] Another embodiment of the present disclosure, a graphene-coated steel sheet, includes a plated steel sheet and a coating layer formed on at least one surface of the steel sheet with the above-described solution composition for graphene-coated steel sheets.

[0021] The above-mentioned plated steel sheet can be at least one selected from the group consisting of galvanized steel sheets, zinc-based alloy plated steel sheets, aluminum-plated steel sheets, aluminum-based alloy plated steel sheets, cold-rolled steel sheets, and hot-rolled steel sheets. Effects of the Invention

[0022] The solution composition for graphene-coated steel sheets according to one embodiment of the present disclosure can have excellent dispersion stability.

[0023] The graphene-coated plated steel sheet according to another embodiment of the present disclosure can have excellent corrosion resistance and adhesion. Modes for Carrying Out the Invention

[0024] The terms used in the present disclosure are for describing the present disclosure, and are not intended to limit the present disclosure. In addition, the singular forms used in the present disclosure also include plural forms unless the relevant definition clearly indicates the opposite meaning.

[0025] The meaning of "comprising" as used in the present disclosure is to specify the presence of stated features, and does not exclude the presence or addition of other features.

[0026] Unless otherwise specifically defined, all terms including technical and scientific terms used in the present disclosure have the same meaning as commonly understood by a person of ordinary skill in the art to which the present disclosure pertains. Terms defined in general dictionaries shall be interpreted to have meanings consistent with those in the relevant technical documents and the currently disclosed content.

[0027] Hereinafter, the present disclosure will be described in detail.

[0028] First, the solution composition for graphene-coated steel sheets according to an embodiment of the present disclosure will be specifically described.

[0029] A solution composition for graphene-coated steel sheets according to one embodiment of the present disclosure may contain 0.1 to 30% by weight of graphene and 55 to 90% by weight of a main resin containing two or more acrylic resins, based on 100% by weight of solids.

[0030] The content of the graphene-coated steel sheet solution composition of this disclosure is not particularly limited, but can be based on, for example, 100% by weight of the total.

[0031] As will be explained in detail later, the above solution composition can form a coating layer on at least one surface of a substrate to which the composition can be applied. In this disclosure, the above substrate can be the plated steel sheets described above, for example, zinc-plated steel sheets, zinc-based alloy plated steel sheets, aluminum-plated steel sheets, aluminum-based alloy plated steel sheets, cold-rolled steel sheets, and hot-rolled steel sheets.

[0032] The following provides a detailed explanation of each component that makes up the above solution composition.

[0033] One embodiment of the graphene-coated steel sheet solution composition may contain graphene. The graphene-coated steel sheet can have improved corrosion resistance, heat dissipation, conductivity, adhesion, strength, and workability. The graphene-coated steel sheet solution composition may contain 0.1 to 30% by weight of graphene per 100% by weight of solids, more specifically 0.1 to 10% by weight, and more specifically 1 to 5% by weight. If the graphene content per 100% by weight of solids is less than 0.1% by weight, the graphene may not exhibit its inherent properties well. If it exceeds 30% by weight, the dispersion stability of the solution may decrease, the corrosion resistance of the coating layer may decrease, and the adhesion between the graphene and the coating layer may be reduced.

[0034] One embodiment of the graphene-coated steel sheet solution composition may contain a main resin comprising two or more acrylic resins. The solution composition containing the main resin can exhibit excellent dispersion stability with graphene and excellent stretchability and processability when coating steel sheets.

[0035] The two or more acrylic resins mentioned above can be two or more selected from the group consisting of copolymers of ethylene acrylic acid (EAA) and polyethylene (PE), copolymers of ethylene acrylic acid (EAA) and polyurethane (PU), polymethyl methacrylate, polyacrylonitrile, cyclohexyl acrylate, glycidyl acrylate, hydroxyalkyl acrylate, etc. Specifically, they can be copolymers of ethylene acrylic acid (EAA) and polyethylene (PE) and copolymers of ethylene acrylic acid (EAA) and polyurethane (PU).

[0036] When the main resin contains two types of acrylic resins, the content ratio of each resin can be 1:1 to 1:6, specifically 1:3 to 1:5. When the main resin contains two types of acrylic resins in the above content ratio, corrosion resistance, processability, and coating adhesion can be improved, and the physical properties of the coating layer can be improved compared to when only one type of acrylic resin is used.

[0037] The main resin mentioned above is not particularly limited, but may further include at least one selected from the group consisting of epoxy resins, urethane resins, fluororesins, polyester resins, polyethylene resins, vinyl chloride resins, and the like.

[0038] The epoxy resin mentioned above can be at least one selected from the group consisting of bisphenol A type resin, bisphenol F type resin, novolac resin, acrylic modified epoxy resin, alicyclic resin, glycidylamine type resin, etc.

[0039] The above-mentioned urethane resin may be at least one selected from the group consisting of polyurethanes produced from isophorone diisocyanate, adipic acid, and polyhydric alcohols, acrylic polyols, polyisocyanates, etc.

[0040] The above-mentioned fluororesin may be a fluorourethane resin obtained using a perfluoroalkyl alcohol, a perfluorolated acrylic polyol, a fluorinated polyolefin polyol, or a mixture thereof, or at least one selected from the group consisting of polymethyl-α-fluoroacrylate, blocked poly-α-fluoroacrylate, polyethyl-α-fluoroacrylate, polyfluoroalkyl acrylate, etc.

[0041] The above-mentioned solution composition for graphene-coated steel sheets may contain 55 to 90% by weight of the main resin per 100% by weight of solids, and more specifically, 60 to 90% by weight. If the content of the main resin per 100% by weight of solids is less than 55% by weight, corrosion resistance, processability, and coating adhesion may deteriorate, and the dispersion stability of graphene may deteriorate. If it exceeds 90% by weight, heat dissipation may deteriorate.

[0042] The graphene-coated steel sheet solution composition of one embodiment may further contain a property improver or other additives.

[0043] The above-mentioned property modifier can improve the adhesion between the steel plate and the coating layer, thereby improving corrosion resistance. The above-mentioned property modifier can 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 more specifically, at least one selected from the group consisting of titanium compounds and ammonium phosphate salts.

[0044] The above-mentioned solution composition for graphene-coated steel sheets may contain 5 to 40% by weight of a property improver based on 100% by weight of solids. If the content of the property improver in the above-mentioned solution composition for graphene-coated steel sheets is less than 5% by weight, the physical properties of the coated steel sheet may deteriorate, and if it exceeds 40% by weight, corrosion resistance, adhesion, and workability may deteriorate.

[0045] The above-mentioned other additives may be at least one selected from the group consisting of leveling agents, wetting agents, curing agents, and defoaming agents.

[0046] The leveling agent described above may be at least one selected from the group consisting of silicone-modified polyacrylate, polyacrylate, fluorine-modified polyacrylate, polysiloxane, etc.

[0047] The above-mentioned wetting agent can be at least one selected from the group consisting of polyether-modified polyalkylsiloxanes, aralkyl-modified polyalkylsiloxanes, polyether-modified siloxanes, high molecular weight fluorine-based surfactants, alcohol alkoxylates (non-silicone type), etc., in order to ensure that the graphene-coated steel sheet solution composition adheres well to the steel sheet.

[0048] The above-mentioned curing agent can 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., in order to enable the graphene-coated steel sheet solution composition to be coated and dried to form a coating film.

[0049] The above-mentioned defoaming agent can be at least one selected from the group consisting of silicone-based, mineral oil-based, polymer-based (silicone and mineral oil-free types), etc., in order to reduce the generation of bubbles when stirring the solution composition for graphene-coated steel sheets and when roll coating.

[0050] The above-mentioned solution composition for graphene-coated steel sheets may contain 1 to 5% by weight of other additives relative to 100% by weight of solids.

[0051] The graphene-coated steel sheet solution composition of one embodiment may further contain the remaining solvent. The solvent may be at least one selected from the group consisting of water, NEP (1-Ethyl-2-Pyrrolidinone), and DMSO (Dimethyl Sulfoxide).

[0052] Next, a steel sheet having a certain coating layer, which has been surface-treated with the above-described solution composition according to another embodiment of this disclosure, will be specifically described.

[0053] The above-mentioned plated steel sheet may be at least one selected from the group consisting of zinc-plated steel sheet, zinc-based alloy plated steel sheet, aluminum-plated steel sheet, aluminum-based alloy plated steel sheet, cold-rolled steel sheet, and hot-rolled steel sheet.

[0054] The upper part of the plated steel sheet described above may include a coating layer formed by coating with the composition of this disclosure in solution, in which case the coating layer may have a thickness of 0.1 to 20 μm.

[0055] If the thickness of the coating layer is less than 0.1 μm, the surface treatment solution composition is thinly applied to the rough peaks on the surface of the plated steel sheet, resulting in a decrease in corrosion resistance. On the other hand, if the thickness exceeds 20 μm, the thick coating layer deteriorates processability, increasing the cost of solution treatment and making it economically disadvantageous.

[0056] Here, the thickness mentioned above refers to the thickness after drying.

[0057] Furthermore, this disclosure describes a method for producing a surface-treated steel sheet using the above composition.

[0058] More specifically, the process may include the steps of: providing a plated steel sheet having a plating layer formed on at least one surface; coating the plating layer with the above-described solution composition; and drying the coated steel sheet.

[0059] The above solution composition can be prepared by adding graphene, the main resin, a property improver, and additives to a solvent in proportions of each, and then stirring.

[0060] When applying the composition of this disclosure to the steel plate in solution, a commonly used coating method can be applied, and therefore, there are no particular limitations.

[0061] For example, the coating process can be carried out by selecting one of the following methods: bar coating, roll coating, spraying, dipping, spray squeezing, dipping squeezing, etc., but is not particularly limited.

[0062] The drying process of the steel sheet coated with the above composition can be carried out in a temperature range of 40 to 280°C, based on the final temperature (PMT) reached by the material (steel sheet).

[0063] If the final temperature reached by the above material is below 40°C, the formation of a robust coating structure may be insufficient, potentially leading to deterioration of corrosion resistance and resistance to blackening. On the other hand, if the temperature exceeds 280°C, the hardness of the coating may increase excessively, degrading the corrosion resistance of the processed area and potentially causing deterioration of surface quality, such as yellowing due to excessive heat.

[0064] The steel sheet, after the above drying process is completed, can have a coating layer with a thickness of 0.1 to 2.0 μm after drying.

[0065] While this disclosure does not particularly limit the means used for the drying process described above, it should be noted that equipment such as induction ovens or hot air drying ovens can be used. The conditions for these facilities can be those of normal use. [Examples]

[0066] The present disclosure will be described in more detail below through examples. However, such examples are provided only to illustrate the implementation of the present disclosure and do not limit the present disclosure. The scope of the present disclosure is determined by the matters described in the claims and matters that can be reasonably inferred therefrom.

[0067] Manufacturing example 1. Preparation of solution compositions for graphene-coated steel sheets (1) Manufacturing Examples 1-8 A solution composition for graphene-coated steel sheets was prepared by stirring graphene, a main resin, and a property improver in the ratios shown in Table 1 below.

[0068] As the main resin component, a copolymer resin containing approximately 2% TMOS (trimethoxysilane) in the side chain of a solvent-free EAA (Ethylene Acrylic Acide) and PE (Polyethylene) copolymer resin, and two types of solvent-free EAA and PU copolymer resins were mixed in a mass ratio of 3:1 to 6:1. A Ti compound and an ammonium phosphate salt were used as property modifiers.

[0069] (2) Comparative manufacturing example 1 A solution composition for graphene-coated steel sheets was prepared using the same method as in the above production example, except that one type of copolymer resin of EAA (Ethylene Acrylic Acide) and PE (Polyethylene) was used as the main resin component.

[0070] (3) Comparative manufacturing example 2 A solution composition for graphene-coated steel sheets was prepared using the same method as in the above production example, except that one type of copolymer resin of EAA and PU was used as the main resin component.

[0071] [Table 1]

[0072] 2. Manufacturing of plated steel sheets The graphene-coated steel sheet solution compositions of Production Examples 1-8 and Comparative Production Examples 1-2 were each coated onto the surface of an electro-galvanized steel sheet using a #10 bar coater, and then dried in a PMT at 180°C for 20 seconds to produce a plated steel sheet with a 5 μm thick coating.

[0073] Plated steel sheets of Examples 1 to 4 were produced using the compositions of Production Examples 1 to 4, respectively, and plated steel sheets of Comparative Examples 1 to 6 were produced using the compositions of Production Examples 5 to 8 and Comparative Production Examples 1 to 2, respectively.

[0074] Evaluation example The dispersion stability of the graphene-coated steel sheet solution compositions for Production Examples 1-8 and Comparative Production Examples 1-2 was evaluated and is shown in Table 2 below. The adhesion and corrosion resistance of the plated steel sheets for Examples 1-4 and Comparative Examples 1-6 were evaluated and are shown in Table 3 below.

[0075] 1.Dispersion stability The dispersion stability of the graphene-coated steel sheet solution compositions from manufacturing examples 1 to 8 was measured by comparing their state after being left in glass containers for one week. The evaluation criteria for dispersion stability are as follows.

[0076] <Criteria for evaluating dispersion stability> ○: No separation from the binder resin. △: Graphene partially separates from the binder resin. ×: Graphene separates from the binder resin and precipitates completely.

[0077] 2. Adhesion The adhesion of the plated steel sheets produced in Examples 1-4 and Comparative Examples 1-6 was evaluated for processing, flat sheeting, and bending processability.

[0078] In the processing section, a cross-cut guide was used to draw 100 grid lines at 1 mm intervals on the surface of the plated steel sheets manufactured in Examples 1-4 and Comparative Examples 1-6 using a sharp blade in a horizontal and vertical grid pattern. The areas marked with the grid were then pushed up to a height of 6 mm using an Erichsen Tester. Scotch tape (Ichiban NB-1) was applied to the pushed-up areas and then peeled off, and the condition of the peeled surface was observed and evaluated.

[0079] A flat plate was prepared by drawing 100 squares in a horizontal and vertical grid pattern at 1 mm intervals. Scotch tape (Ichiban NB-1) was immediately applied to the surface, then peeled off, and the condition of the peeled surface was observed and evaluated.

[0080] For both the processed section and the flat plate, the evaluation results were displayed as "Number of attached parts / 100". That is, if there were no parts peeled off from the surface, it was displayed as "100 / 100", if 10 peeling occurred it was displayed as "90 / 100", and if 20 peeling occurred it was displayed as "80 / 100".

[0081] Bending was performed by bending the surface of the coated specimen by 180° and then clamping it in a vise until it was flat (0, 1, 2, 3T-Bending). The degree of coating delamination and crack formation was evaluated at the bent portion.

[0082] 3. Corrosion resistance In Examples 1-4 and Comparative Examples 1-6, plated steel sheets were processed to produce cup-shaped specimens. These specimens were then subjected to a salt spray test using a salt spray tester (SST) with a 5% salt concentration and a temperature of 35°C at a rate of 1 kg / cm³. 2 After uniformly spraying at the specified pressure, the time it took for red rust to form on the side of a cup-shaped specimen was measured. The evaluation criteria for the corrosion resistance are as follows.

[0083] <Criteria for evaluating corrosion resistance> ◎: White rust formation time is 72 hours or more. ○: White rust formed between 48 hours and less than 72 hours △: White rust occurred between 24 hours and less than 48 hours.

[0084] [Table 2]

[0085] [Table 3]

[0086] Referring to Table 2, it can be seen that the compositions of Manufacturing Examples 1-5 and 8 in this disclosure exhibit excellent dispersion stability.

[0087] On the other hand, it can be confirmed that the compositions of Production Examples 6 and 7, which have a low content of the main resin, lack dispersion stability, and it can also be confirmed that the dispersion stability of Comparative Production Examples 1 and 2, which use only one type of main resin, is also lacking.

[0088] Referring to Table 3, it can be confirmed that the plated steel sheets of Examples 1 to 4 according to this disclosure have excellent adhesion and corrosion resistance.

[0089] On the other hand, it can be confirmed that the plated steel sheets of Comparative Examples 1 to 6 lacked adhesion and corrosion resistance. Specifically, it was determined that the plated steel sheets of Comparative Examples 1 to 3 had a low content of the main resin and were unable to form a solid coating layer, the plated steel sheet of Comparative Example 4 had a high content of the main resin and a low content of the property improver, resulting in a deterioration of the physical properties of the coated steel sheet, and the plated steel sheets of Comparative Examples 5 and 6 were determined to have insufficient adhesion and corrosion resistance because only one type of main resin was used, which deteriorated the dispersion stability of graphene.

Claims

1. For 100% by weight of solids, Graphene 0.1-30% by weight, A solution composition for graphene-coated steel sheets, comprising 55 to 90% by weight of a main resin containing two or more types of acrylic resins.

2. The solution composition for graphene-coated steel sheets according to claim 1, wherein the two or more acrylic resins are selected from the group consisting of copolymers of ethylene acrylic acid (EAA) and polyethylene (PE), copolymers of ethylene acrylic acid (EAA) and polyurethane (PU), polymethyl methacrylate, polyacrylonitrile, cyclohexyl acrylate, glycidyl acrylate, and hydroxyalkyl acrylate.

3. The solution composition for graphene-coated steel sheets according to claim 1, wherein the main resin further comprises at least one selected from the group consisting of epoxy resins, urethane resins, fluororesins, polyester resins, polyethylene resins, and vinyl chloride resins.

4. The solution composition for graphene-coated steel sheets according to claim 3, 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, alicyclic resin, and glycidylamine type resin.

5. The urethane resin is at least one selected from the group consisting of polyurethane produced from isophorone diisocyanate, adipic acid, and polyhydric alcohol, acrylic polyol, and polyisocyanate, as described in claim 3, for use as a solution composition for graphene-coated steel sheets.

6. The fluorine-based resin is a fluorine-based urethane resin obtained using a perfluoroalkyl alcohol, a perfluorolated acrylic polyol, a fluorinated polyolefin-based polyol, or a mixture thereof, or at least one selected from the group consisting of polymethyl-α-fluoroacrylate, blocked poly-α-fluoroacrylate, polyethyl-α-fluoroacrylate, and polyfluoroalkyl acrylate, as described in claim 3, for use in a graphene-coated steel sheet solution composition.

7. The solution composition for graphene-coated steel sheets according to claim 1, further comprising a property improver or other additive.

8. The property improving agent is at least one selected from the group consisting of titanium compounds, ammonium phosphate salts, vanadium compounds, organic phosphoric acids, phosphate amine salts, and organic acids, as described in claim 7, for the solution composition for graphene-coated steel sheets.

9. The solution composition for graphene-coated steel sheets according to claim 7, wherein the property improving agent is contained in an amount of 5 to 40% by weight based on 100% by weight of solids.

10. The solution composition for graphene-coated steel sheets according to claim 7, wherein the other additives are at least one selected from the group consisting of leveling agents, wetting agents, curing agents, and defoaming agents.

11. The solution composition for graphene-coated steel sheets according to claim 7, wherein the other additives are contained in an amount of 1 to 5% by weight based on 100% by weight of solids.

12. The composition further comprises the remaining solvent, The solvent is at least one selected from the group consisting of water, NEP (1-ethyl-2-pyrrolidinone), and DMSO (dimethyl sulfoxide), as described in claim 1, for the solution composition for graphene-coated steel sheets.

13. Plated steel sheet and A graphene-coated steel sheet comprising a coating layer formed on at least one surface of the steel sheet with a graphene-coated steel sheet solution composition according to any one of claims 1 to 12.

14. The graphene-coated steel sheet according to claim 13, wherein the plated steel sheet is at least one selected from the group consisting of zinc-plated steel sheet, zinc-based alloy plated steel sheet, aluminum-plated steel sheet, aluminum-based alloy plated steel sheet, cold-rolled steel sheet, and hot-rolled steel sheet.

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