Method for manufacturing a coating composition

Abstract

A method for producing a coating composition according to one embodiment of this application includes the steps of: mixing a zirconium precursor and a first polyhydric alcohol to produce a first solution; adding a binder to the first solution to produce a second solution; and adding ethanol, polysorbic acid, and a second polyhydric alcohol to the second solution to produce a third solution, satisfying the above formula 1.

Description

Technical Field

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2024-0005139, filed with the Korean Intellectual Property Office on January 12, 2024, and all of its contents are incorporated herein.

[0002] This application relates to a method for manufacturing a coating composition.

Background Art

[0003] Metal structures can be applied in various fields such as lightweight, sound insulation, heat insulation, energy absorption, filtration, and catalysts, but in some cases, passivation is required. Generally, it is easy to coat a passivation layer on a flat substrate such as glass or silicon, but since the surface of the above metal structure is very uneven, there is a problem that it is difficult to form a uniform passivation layer on such a surface.

[0004] In addition, zirconium dioxide has a very high melting point and a relatively low coefficient of thermal expansion, so it has strong resistance to chemical reactions and environmental degradation. Due to such characteristics, it can be applied as a passivation material in various application fields to protect the material surface and prevent chemical degradation such as corrosion and oxidation.

[0005] Therefore, in this technical field, there is a need for the development of a technology for forming a passivation layer on a metal structure using zirconium dioxide.

Summary of the Invention

Problems to be Solved by the Invention

[0006] This application aims to provide a method for manufacturing a coating composition that can be applied to various uses.

Means for Solving the Problems

[0007] One embodiment of this application is A step of preparing a first solution by mixing a zirconium precursor and a first polyhydric alcohol; The step of adding a binder to the first solution to produce a second solution; and The process includes the step of adding ethanol, polysorbic acid, and a second polyhydric alcohol to the second solution to produce a third solution. The present invention provides a method for manufacturing a coating composition that satisfies the following formula 1. [Formula 1] (Molar concentration of Zr in the second solution) × (Weight ratio of the second solution to the total weight of the second solution, ethanol, and polysorbic acid) < 0.11

[0008] Furthermore, other embodiments of this application include: Steps to prepare the substrate; and The step of coating the surface of the substrate with the coating composition produced by the above manufacturing method, drying and firing it to form a zirconium dioxide coating layer on the surface of the substrate. The present invention provides a method for producing a zirconium dioxide coating layer, including [the specified component]. [Effects of the Invention]

[0009] According to one embodiment of this application, it is possible to provide a method for manufacturing a coating composition in which a zirconium dioxide coating layer can be uniformly formed on the surface of a substrate such as a metal structure, and which can serve as a passivation layer.

[0010] Furthermore, by forming a zirconium dioxide coating film on the surface of a metal structure using a coating composition manufactured according to one embodiment of this application, it is possible to provide a metal structure that can be applied and used in a variety of fields such as weight reduction, sound insulation, heat insulation energy absorption, and filtration catalysts. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows a surface SEM image of a metal structure coated according to Example 1. [Figure 2] It is a figure showing a surface SEM image of a metal structure coated according to Example 6. [Figure 3] It is a figure showing an XRD image of a powder sample obtained by heat-treating a dried powder of the coating composition of Example 8 at 700 °C for 3 hours. [Figure 4] It is a figure showing a SEM image of a powder sample obtained by heat-treating a dried powder of the coating composition of Example 8 at 700 °C for 3 hours. [Figure 5] It is a figure showing a surface SEM image of a metal structure coated according to Example 8. [Figure 6] It is a figure showing a high-magnification SEM image of a passive film coated according to Example 8. [Figure 7] It is a figure showing a surface SEM image of a metal structure coated according to Comparative Example 2. [Figure 8] It is a figure showing a surface SEM image of a metal structure coated according to Comparative Example 3. [Figure 9] It is a figure showing a surface SEM image of a metal structure coated according to Comparative Example 5.

Mode for Carrying Out the Invention

[0012] Hereinafter, this specification will be described in more detail.

[0013] In this specification, when a certain member is located "above" another member, this includes not only the case where a certain member is in contact with another member, but also the case where there is another member between the two members.

[0014] In this specification, when a certain part "includes" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components, but can further include other components.

[0015] The method for manufacturing a coating composition according to an embodiment of the present application includes the steps of mixing a zirconium precursor and a first polyhydric alcohol to produce a first solution; adding a binder to the first solution to produce a second solution; and adding ethanol, polyvinyl acid, and a second polyhydric alcohol to the second solution to produce a third solution, which satisfies the following formula 1. [Formula 1] (Molar concentration of Zr in the second solution) × (Weight ratio of the second solution to the total weight of the second solution, ethanol, and polyvinyl acid) < 0.11

[0016] The method for manufacturing a coating composition according to an embodiment of the present application includes the step of mixing a zirconium precursor and a first polyhydric alcohol to produce a first solution.

[0017] The zirconium precursor is a precursor of zirconium dioxide that constitutes the coating layer, and its content can be adjusted to adjust the molar ratio of zirconium. The zirconium precursor may be zirconium propoxide, but is not limited thereto.

[0018] The first polyhydric alcohol can include one or more of 1,4-butanediol, diethylene glycol, and triethylene glycol. Also, the first polyhydric alcohol can simultaneously include 1,4-butanediol and diethylene glycol, can simultaneously include 1,4-butanediol and triethylene glycol, and can simultaneously include 1,4-butanediol, diethylene glycol, and triethylene glycol.

[0019] The step of producing the first solution described above can be carried out at a temperature of 70°C to 130°C, or at a temperature of 80°C to 100°C. If the step of producing the first solution described above is carried out at a temperature below 70°C, the zirconium precursor may not dissolve well, which is undesirable. Also, if the step of producing the first solution described above exceeds 130°C, particle precipitation due to hydration reaction may occur, which is undesirable.

[0020] A method for producing a coating composition according to one embodiment of this application includes the step of adding a binder to the first solution to produce a second solution.

[0021] According to one embodiment of this application, by adding a binder to the first solution, the adhesion of the manufactured coating layer can be improved, and the desorption phenomenon of the zirconium dioxide thin film can be prevented even after high-temperature heat treatment.

[0022] The above binder may contain polyvinylpyrrolidone (PVP).

[0023] The content of the above binder may be 1% to 5% by weight based on the total weight of 1,4-butanediol applied to the first polyhydric alcohol, but is not limited to this.

[0024] A method for producing a coating composition according to one embodiment of this application includes the step of adding ethanol, polysorbic acid, and a second polyhydric alcohol to the second solution to produce a third solution.

[0025] The polysorbic acid described above can act as a stabilizer and dispersant, and more specifically, it can stabilize the sol by suppressing the aggregation of Zr particles. Furthermore, the second polyhydric alcohol described above can replace some of the Zr particles bonded to the first polyhydric alcohol, such as 1,4-butanediol, diethylene glycol, or triethylene glycol, with hydroxyl groups, thereby causing them to precipitate as particles.

[0026] Based on the total weight of the second solution and ethanol, the content of the second solution may be 1% to 40% by weight, preferably 5% to 30% by weight. When the content of the second solution is 1% to 40% by weight based on the total weight of the second solution and ethanol, a uniform and reproducible coating layer can be formed when coating the surface of a substrate such as a metal structure with the composition. When the content of the second solution exceeds 40% by weight based on the total weight of the second solution and ethanol, there is a risk that non-uniform gelation will occur during the drying process, blocking the open pores / cells of the metal structure, which may lead to a decrease in the adhesion of the dried thin film, and this is undesirable.

[0027] Based on the total weight of the second solution and ethanol, the polysorbic acid content may be 5% to 45% by weight, or 10% to 40% by weight. If the polysorbic acid content exceeds 45% by weight based on the total weight of the second solution and ethanol, it is undesirable because the viscosity of the final composition will increase, which may cause defects when coating substrates such as metal structures.

[0028] The second polyhydric alcohol mentioned above may include ethylene glycol.

[0029] Based on the total weight of the second solution and ethanol, the content of the second polyhydric alcohol may be 0.5% to 10% by weight, or 1% to 5% by weight. If the content of the second polyhydric alcohol is less than 0.5% by weight based on the total weight of the second solution and ethanol, the hydration reaction will occur very slowly, which may lead to increased process time for particle formation, and is therefore undesirable. Furthermore, if the content of the second polyhydric alcohol exceeds 10% by weight based on the total weight of the second solution and ethanol, the hydration reaction will occur rapidly, the composition will turn into a paste-like substance, and it will not be possible to coat the surface of the metal structure, which is also undesirable.

[0030] The coating composition according to one embodiment of this application may have a value of formula 1 less than 0.11, 0.105 or less, or 0.1 or less. By satisfying the value of formula 1, the coating composition according to one embodiment of this application can uniformly form a coating layer, which is a uniform zirconium dioxide thin film, on the surface of a substrate such as a metal structure. If the value of formula 1 is 0.11 or greater, there is a risk that the composition itself may harden or become paste-like due to an excessive hydration reaction during the process of adding the second polyhydric alcohol, which is undesirable. Therefore, in this application, it was found that the solution state before adding the second polyhydric alcohol has the greatest influence on the process of coating the metal structure, and the inventors conducted experiments under various conditions to numerically quantify the solution state before adding the second polyhydric alcohol, and derived formula 1 as a result.

[0031] In one embodiment of this application, the value of Formula 1 must be satisfied, so the concentration of zirconia should not be too high in order to form a thick zirconium dioxide coating film. Also, in one embodiment of this application, the value of Formula 1 can be reduced by increasing the degree of dispersion by adding polysorbic acid, but the amount of ethanol must also be taken into consideration at the same time, so it is necessary to appropriately adjust the content of polysorbic acid and ethanol to satisfy Formula 1.

[0032] In one embodiment of this application, the pH of the coating composition may be 6.5 to 7.5, 6.8 to 7.2, or 7. By satisfying the pH range of the coating composition, chemical changes in the metal structure can be prevented.

[0033] In one embodiment of this application, the coating composition can be applied to passivation layers for metal structures, high-refractive index coating layers for glass substrates, heat shielding coating layers for gas turbines, or bioceramic coating layers for artificial bones, and is more preferably applied to passivation layers for metal structures.

[0034] The passivation layer of the above-mentioned metal structure can be applied even to metal structures with severe surface irregularities, and can therefore be applied as a passivation material in various application fields to protect the material surface and prevent chemical degradation such as corrosion and oxidation.

[0035] The high-refractive index coating layer on the glass substrate described above can be applied to adjust the reflection of the glass substrate to prevent glare, and can therefore be applied to smart glasses and the like.

[0036] The heat shielding coating layer of the above-mentioned gas turbine can be applied to power generation and aircraft gas turbines to obtain heat insulation effects.

[0037] The bioceramic coating layer of the artificial bone described above can be applied to hydroxyapatite, which is an artificial bone material, to further improve its biocompatibility.

[0038] Furthermore, a method for manufacturing a zirconium dioxide coating layer according to one embodiment of this application includes the steps of: preparing a substrate; and coating the surface of the substrate with the coating composition manufactured by the above manufacturing method, drying and firing it to form a zirconium dioxide coating layer on the surface of the substrate.

[0039] As described above, the zirconium dioxide coating film may be a passivation layer for a metal structure, a high-refractive index coating layer for a glass substrate, a heat shielding coating layer for a gas turbine, or a bioceramics coating layer for an artificial bone, and is more preferably a passivation layer for a metal structure.

[0040] The above metal structure may be a metal foam containing NiCrAlFe, NiCrAl, SiC, or α-Al2O3.

[0041] The above-mentioned metal structure is a structure having various shapes, possessing low heat capacity and excellent heat transfer ability, and can be molded into a desired shape for use. The form, size, etc., of the above-mentioned metal structure are not particularly limited, and the porosity of the above-mentioned metal structure may be 10% to 99%, 50% to 96%, or 85% to 96%. The pore size (cell size) of the above-mentioned metal structure may be 400 μm to 1,500 μm, or 450 μm to 1,400 μm. If the pore size of the above-mentioned metal structure is less than 400 μm, coating with the precursor solution becomes difficult, and if it exceeds 1,500 μm, the amount of catalyst that can be supported decreases, which may be disadvantageous in the process, so it is undesirable. The above-mentioned metal structure can be appropriately manufactured by a person skilled in the art using methods known in the art, taking into consideration the material, pore size, porosity, etc. of the metal structure described above.

[0042] In one embodiment of this application, the method for coating the surface of the substrate with the coating composition can be any method known in the art, such as dip coating or wash coating, but is not limited to these.

[0043] In one embodiment of this application, the drying can be carried out at a temperature of 50°C to 250°C for 1 to 48 hours, or at a temperature of 70°C to 200°C for 5 to 36 hours, but is not limited thereto. Furthermore, the firing can be carried out in an air atmosphere at a temperature of 400°C to 1,300°C for 1 to 30 hours, or at an air atmosphere at a temperature of 600°C to 900°C for 2 to 24 hours, but is not limited thereto. If the firing is carried out at a temperature exceeding 1,300°C, the physical properties of the substrate itself may change, affecting the strength, length shrinkage, pore size, etc., and potentially impacting the quality of the zirconium dioxide coating film, which is undesirable. [Examples]

[0044] The present application will be described in detail below with reference to examples. However, the examples relating to this application can be modified into various different forms, and the scope of this application should not be construed as being limited to the examples detailed below. The examples of this application are provided to give a more complete explanation of this application to a person of average knowledge in the art.

[0045] <Examples> <Manufacturing Example 1> 1,4-butanediol (25 mL) was mixed with diethylene glycol (7.98 g) and zirconium propoxide (7.04 g) while stirring. The mixture was heated to 100°C while maintaining stirring and maintained for 5 hours to prepare the first solution.

[0046] Subsequently, the first solution described above was cooled to room temperature, and PVP (0.46g, polyvinylpyrrolidone, M) was added as a binder. W After adding (40,000 g / mol), the mixture was thoroughly mixed until dissolved to prepare a second solution. The molar concentration of Zr in the second solution of the above preparation example 1 was 0.6 M.

[0047] <Manufacturing Example 2> 1,4-butanediol (30 mL) was mixed with diethylene glycol (6.37 g) and zirconium propoxide (5.62 g) while stirring. The mixture was heated to 80°C while maintaining stirring and maintained for 5 hours to prepare the first solution.

[0048] Subsequently, the first solution described above was cooled to room temperature, and PVP (0.55g, polyvinylpyrrolidone, M) was added as a binder. W After adding (40,000 g / mol), the mixture was thoroughly mixed until dissolved to prepare a second solution. The molar concentration of Zr in the second solution of the above preparation example 2 was 0.4 M.

[0049] <Manufacturing Example 3> 1,4-butanediol (40 mL) was mixed with diethylene glycol (4.30 g) and zirconium propoxide (3.79 g) while stirring. The mixture was heated to 90°C while maintaining stirring and maintained for 5 hours to prepare the first solution.

[0050] Subsequently, the first solution described above was cooled to room temperature, and PVP (0.74g, polyvinylpyrrolidone, M) was added as a binder. W After adding (40,000 g / mol), the mixture was thoroughly mixed until dissolved to prepare a second solution. The molar concentration of Zr in the second solution of the above preparation example 3 was 0.2 M.

[0051] <Manufacturing Example 4> 1,4-butanediol (40 mL) was mixed with diethylene glycol (10.61 g) and zirconium propoxide (9.36 g) while stirring. The mixture was heated to 90°C while maintaining stirring and maintained for 5 hours to prepare the first solution.

[0052] Subsequently, the first solution described above was cooled to room temperature, and PVP (0.74g, polyvinylpyrrolidone, M) was added as a binder. W After adding (40,000 g / mol), the mixture was thoroughly mixed until dissolved to prepare a second solution. The molar concentration of Zr in the second solution of the above preparation example 4 was 0.5 M.

[0053] <Example 1> The second solution from Production Example 1 above, ethanol, and polysorbic acid were thoroughly mixed in the constant ratios shown in Table 1 below. Ethylene glycol was further added to the mixture and stirred to induce a particle precipitation reaction, producing a third solution, which is a dispersion. The pH of the third solution was 7.

[0054] After immersing the metal structure (NiCrAl) in the third solution described above, ultrasonic vibration was applied for several seconds to remove air bubbles from within the metal structure. Then, dip coating was performed, and after the dip coating was complete, a centrifuge was used to remove the filtrate (300 rpm, 5 minutes). The coated metal structure was then dried in an oven at 150°C. The dried metal structure was placed in a furnace and heated in an air atmosphere at 700°C for 6 hours to produce a metal structure with a zirconium dioxide coating film as a passivation layer on its surface.

[0055] <Examples 2-9 and Comparative Examples 1-6> As shown in Table 1 below, the procedure was the same as in Example 1, except that the type and content of the second solution and the content of ethanol, polysorbic acid, and ethylene glycol were adjusted. In Comparative Example 5, butanol was used instead of ethanol.

[0056] Furthermore, the values ​​of Formula 1 for the above examples and comparative examples were calculated and are shown in Table 2 below.

[0057] [Table 1]

[0058] [Table 2]

[0059] A: Molar concentration (M) of Zr in the second solution B: Weight ratio of the second solution to the total weight of the second solution, ethanol, and polysorbic acid.

[0060] Figure 1 shows a surface SEM image of a metal structure coated according to Example 1.

[0061] Figure 2 shows a surface SEM image of a metal structure coated according to Example 6.

[0062] Figure 3 shows an XRD image of a powder sample obtained by heat-treating the dried powder of the coating composition of Example 8 at 700°C for 3 hours.

[0063] Figure 4 shows an SEM image of a powder sample obtained by heat-treating the dried powder of the coating composition of Example 8 at 700°C for 3 hours.

[0064] Figure 5 shows a surface SEM image of a metal structure coated according to Example 8.

[0065] Figure 6 shows a high-magnification SEM image of the passivation film coated according to Example 8.

[0066] Figure 7 shows a surface SEM image of a metal structure coated according to Comparative Example 2.

[0067] Figure 8 shows a surface SEM image of a metal structure coated according to Comparative Example 3.

[0068] Figure 9 shows a surface SEM image of a metal structure coated according to Comparative Example 5.

[0069] As shown in Figures 1, 2, and 5 below, by satisfying the value of Equation 1 above, it can be confirmed that the coated zirconium dioxide film effectively covers the surface of the metal structure without producing defects such as cracks or pinholes. Due to the characteristics of the manufacturing process for the metal structure, many large three-dimensional irregularities are inevitably formed, but despite the presence of such irregularities, the surface of the metal structure was coated very smoothly. Furthermore, although the amount coated on the surface of the metal structure may vary depending on the concentration and viscosity of the zirconia solution and the coating conditions, it was confirmed that typically 1% to 3% by weight is coated. Such a uniform coating film effectively protects the metal structure chemically from the outside, which is similar to painting the surface of an automobile to prevent corrosion. In addition, by increasing the number of coatings as needed, the thickness of the passivation film can be increased, thereby further enhancing the protective effect of the metal structure. Furthermore, when a catalyst is further coated onto a metal structure on which a zirconium dioxide thin film has been formed, the zirconium dioxide thin film acts as a barrier, preventing some substances from diffusing from the metal structure into the catalyst layer.

[0070] After the coating process, a supporting metal structure is present. To facilitate analysis of the crystalline phase, the coating solution was dried separately and then heat-treated at 700°C. The resulting powder was then measured by XRD. As shown in Figure 3 below, the crystalline structure of zirconium dioxide is confirmed to be a mixture of monoclinic and tetragonal crystals. By calculating the amounts through Rietveld quantitative analysis, it was confirmed that approximately 85.5% was tetragonal and approximately 14.5% was orthorhombic.

[0071] Furthermore, as shown in Figure 4 below, it was confirmed that the grain size of the zirconium dioxide crystals is approximately 15 nm to 30 nm. Figure 6 shows the results of observing the zirconium dioxide passivation film coated on a metal structure under high magnification using a scanning electron microscope (SEM), confirming that its crystal grain structure is similar to that of Figure 4.

[0072] However, in the cases of Comparative Examples 1, 4, and 6 described above, the value of Formula 1 was 0.11 or higher, resulting in severe gelation of the coating solution over time, making the subsequent dip coating process impossible.

[0073] Furthermore, in the case of Comparative Examples 2-4, where polysorbic acid was not added, as shown in Figures 7 and 8 below, the uniformity of the coating film was greatly reduced, and it could be seen that only parts of the metal structure were coated, like islands, leaving the surface exposed.

[0074] Furthermore, in Comparative Example 5, where butanol was used instead of ethanol during the preparation of the third solution, a uniform coating film could not be formed due to a decrease in the dispersibility of the solution and an increase in surface energy, as shown in Figure 9 below.

Claims

1. A step of preparing a first solution by mixing a zirconium precursor and a first polyhydric alcohol; The steps of adding a binder to the first solution to produce a second solution; and The process includes the step of adding ethanol, polysorbic acid, and a second polyhydric alcohol to the second solution to produce a third solution. A method for producing a coating composition that satisfies the following formula 1: [Formula 1] (Molar concentration of Zr in the second solution) × (Weight ratio of the second solution to the total weight of the second solution, ethanol, and polysorbic acid) < 0.

11.

2. The method for producing the coating composition according to claim 1, wherein the zirconium precursor is zirconium propoxide.

3. The method for producing the coating composition according to claim 1, wherein the first polyhydric alcohol comprises one or more of 1,4-butanediol, diethylene glycol, and triethylene glycol.

4. The method for producing a coating composition according to claim 1, wherein the step of producing the first solution is carried out at a temperature of 70°C to 130°C.

5. The method for producing the coating composition according to claim 1, wherein the binder contains polyvinylpyrrolidone (PVP).

6. A method for producing the coating composition according to claim 1, wherein the second polyhydric alcohol contains ethylene glycol.

7. The method for producing the coating composition according to claim 1, wherein the pH of the coating composition is 6.5 to 7.

5.

8. The method for producing the coating composition according to claim 1, wherein the coating composition is applied to a passivation layer for a metal structure, a high-refractive index coating layer for a glass substrate, a heat shielding coating layer for a gas turbine, or a bioceramics coating layer for an artificial bone.

9. Steps to prepare the substrate; and The step of coating the surface of the substrate with a coating composition manufactured according to any one of claims 1 to 7, drying and firing it to form a zirconium dioxide coating layer on the surface of the substrate. A method for producing a zirconium dioxide coating layer, including [the specified component].

10. The method for manufacturing a zirconium dioxide coating layer according to claim 9, wherein the zirconium dioxide coating layer is a passivation layer for a metal structure, a high refractive index coating layer for a glass substrate, a heat shielding coating layer for a gas turbine, or a bioceramic coating layer for an artificial bone.

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