Antifouling article

Abstract

The present disclosure relates to anti-fouling articles. More specifically, the present disclosure relates to articles capable of preventing fouling caused by inorganic chlorides.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0121583, filed with the Korean Intellectual Property Office on September 26, 2022, and Korean Patent Application No. 10-2023-0129096, filed with the Korean Intellectual Property Office on September 26, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0003] This disclosure relates to articles for preventing scale buildup. More specifically, this disclosure relates to articles capable of preventing scale buildup caused by inorganic chlorides. Background Technology

[0004] Anti-scaling coatings are used in industry to prevent foreign matter from adhering to the surface of various equipment or to prevent contaminants from adhering to the surface of various equipment.

[0005] Chlorine (Cl) dust is generated as a byproduct during the recycling of waste plastics in cement production. Due to recent environmental concerns, separate chlorine dust treatment facilities are being used to extract additional potassium chloride (KCl) from the chlorine dust, which is a byproduct.

[0006] However, during this chlorine dust treatment process, fouling caused by potassium chloride frequently occurs on the surfaces inside the facility, and when fouling occurs, there is a problem of a significant reduction in process operating rate.

[0007] Therefore, in order for the process to operate smoothly, it is necessary to prevent inorganic chloride contaminants (such as potassium chloride) from adhering to the inner surfaces of the treatment facility.

[0008] However, the stainless steel surfaces commonly used as substrates for such treatment facilities have high wettability and are prone to contamination due to their nature, thus requiring regular cleaning. Furthermore, methods exist for applying super-hydrophobic or hydrophobic coatings to prevent contaminant adhesion. However, even with such coatings, it is not easy to prevent or remove inorganic chloride contaminants, and the coatings are not very durable, so their effectiveness cannot last long.

[0009] Therefore, there is a need to study anti-scaling coatings that prevent inorganic chloride contaminants from adhering to the inner surface of equipment and that allow for easy removal of contaminants even if they are stuck. Summary of the Invention

[0010] Technical issues

[0011] To address the aforementioned problems, scale-inhibiting products including scale-inhibiting coatings that prevent inorganic chlorides are provided.

[0012] Technical solution

[0013] According to one embodiment of this disclosure, an anti-scaling article is provided, comprising:

[0014] Base; and

[0015] A scale-preventing coating against inorganic chlorides is disposed on at least one side of the substrate.

[0016] The scale-inhibiting coating that prevents inorganic chlorides satisfies the following formulas 1 to 3:

[0017] [Formula 1]

[0018] 80° <REC<150°

[0019] [Equation 2]

[0020] REC / CAH ≥ 2.5

[0021] [Formula 3]

[0022] CAH≥25°

[0023] In equations 1 to 3,

[0024] REC is the receding contact angle to water (unit: °), and

[0025] CAH stands for Contact Angle Hysteresis, which is the difference between the advancing contact angle (in °) and the retreating contact angle (in °) of water.

[0026] Beneficial effects

[0027] The anti-scaling products according to this disclosure can effectively prevent fouling caused by inorganic chlorides.

[0028] In particular, it can effectively prevent potassium chloride (KCl) from adhering to the inner wall of the treatment equipment, wherein potassium chloride is generated during the chlorine dust treatment process, which further extracts potassium chloride from chlorine dust generated as a byproduct during the recycling of waste plastics during cement production. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the process of forming salt arches on the surface of an anti-scaling coating according to one embodiment of the present disclosure.

[0030] Figure 2 A cross-sectional view of a salt arch according to one embodiment of the present disclosure is shown schematically.

[0031] Figure 3 This is a schematic diagram illustrating the process by which salt arches are not formed on the surface of a coating according to a comparative example of the present disclosure.

[0032] Figure 4 This is a schematic diagram illustrating the process by which salt arches are not formed on the surface of a substrate according to a comparative example of the present disclosure.

[0033] Figure 5 Photographs of a salt arch (A) according to one embodiment of the present disclosure and comparative arches (B, C) are shown. Detailed Implementation

[0034] In this disclosure, the terms “first,” “second,” etc., are used to describe multiple components, and are used only to distinguish one component from others.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0036] Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well.

[0037] It should be further understood that the terms “comprising,” “including,” or “having” as used in this disclosure specify the presence of the said feature, number, step, component, or combination thereof, but do not exclude the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0038] Furthermore, as used herein, when referring to a layer or element being formed “on” a layer or element, the layer or element may be formed directly on the layer or element, or additional layers or elements may be formed between layers, on an object, or on a substrate.

[0039] Because the present invention can be modified in various ways and has various forms, specific embodiments thereof are shown by way of example and will be described in detail. However, this is not intended to limit the invention to the specific forms disclosed, but it should be understood that the invention includes all modifications, equivalents and alternatives within the concept and scope of the invention.

[0040] The anti-scaling article according to one embodiment of the present invention will be described in detail below.

[0041] An anti-scaling article according to one embodiment of the present disclosure includes: a substrate; and an anti-scaling coating against inorganic chlorides disposed on at least one side of the substrate, wherein the anti-scaling coating against inorganic chlorides satisfies the following formulas 1 to 3:

[0042] [Formula 1]

[0043] 80° <REC<150°

[0044] [Equation 2]

[0045] REC / CAH ≥ 2.5

[0046] [Formula 3]

[0047] CAH≥25°

[0048] In equations 1 to 3,

[0049] REC is the receding contact angle with water (unit: °), and

[0050] CAH stands for contact angle hysteresis, which is the difference between the forward contact angle (unit: °) and the backward contact angle (unit: °) of water.

[0051] As used herein, the term "contact angle" refers to the angle between the gas / liquid interface formed by a droplet placed on a solid surface and the solid surface. This contact angle can be measured by various methods, and in this specification, the contact angle of the droplet is measured using the stop-drop method with a commercial contact angle measuring device (manufactured by KRUSS, model name: DSA-100).

[0052] The contact angle is a measure of the wettability of a surface. A small contact angle indicates high wettability, while a large contact angle indicates low wettability.

[0053] Furthermore, in this specification, the term "advancing contact angle" refers to the maximum contact angle achievable without moving the contact line between the droplet and the surface. In actual measurements, it is defined as the contact angle at which the contact line of the droplet begins to move while small amounts of water are continuously added.

[0054] Furthermore, in this specification, the term "receding contact angle" refers to the minimum contact angle achievable without moving the contact line between the droplet and the surface. In actual measurements, it is defined as the angle just before the three-phase (solid / liquid / gas) interface moves as the amount of water passing through the syringe needle gradually decreases.

[0055] Furthermore, in this specification, the forward contact angle and backward contact angle are measured using a water droplet at atmospheric pressure (1 atmosphere) and 25°C.

[0056] Additionally, the term "CAH" used in this paper refers to contact angle hysteresis, which is the difference between the advancing contact angle and the retreating contact angle as measured above.

[0057] In researching methods to prevent contaminants (especially inorganic chlorides) from adhering to the surface of a substrate or coating, the inventors discovered that when the contact angle of the surface meets predetermined conditions, the coating exhibits excellent durability and can effectively prevent the adhesion of inorganic chloride contaminants, thus completing this invention.

[0058] More specifically, when the surface of the coating meets the contact angle conditions of one embodiment of this disclosure, it is determined that even if a solution containing inorganic chlorides, such as potassium chloride (KCl), adheres to the surface of the coating, it dries in a hollow, dome-shaped form and has a minimal contact area with the surface of the coating. Therefore, fouling caused by inorganic chlorides can be prevented, and the dome shape is maintained even after drying, allowing it to be removed as is, making contaminant removal very easy.

[0059] Furthermore, it was determined that an arch would not form or remain simply because the surface of the coating is hydrophobic or has a large contact angle, and that an arch could only be formed during drying if the receding contact angle, contact angle hysteresis, and the ratio of receding contact angle to contact angle hysteresis according to Formulas 1 to 3 of an embodiment of the invention met certain conditions.

[0060] As an example, the scale-inhibiting coating for inorganic chlorides disclosed herein satisfies all of the following formulas 1 to 3.

[0061] [Formula 1]

[0062] 80° <REC<150°

[0063] [Equation 2]

[0064] REC / CAH ≥ 2.5

[0065] [Formula 3]

[0066] CAH≥25°

[0067] In equations 1 to 3,

[0068] REC is the receding contact angle with water (unit: °), and

[0069] CAH stands for contact angle hysteresis, which is the difference between the forward contact angle (unit: °) and the backward contact angle (unit: °) of water.

[0070] According to one embodiment of this disclosure, the scale-inhibiting coating against inorganic chlorides satisfies Formula 1 above. That is, the retreat contact angle (REC) can be greater than 80°, 85° or greater, 90° or greater, 95° or greater, or 100° or greater, and less than 150°, 145° or less, 140° or less, 135° or less, or 130° or less.

[0071] Furthermore, the scale-inhibiting coating against inorganic chlorides according to one embodiment of this disclosure satisfies Equation 2 above. That is, the ratio of receding contact angle to contact angle hysteresis (REC / CAH) can be 2.5 or greater, 2.8 or greater, 3.0 or greater, 3.1 or greater, or 3.2 or greater, and 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, or 3.5 or less.

[0072] Furthermore, the scale-inhibiting coating against inorganic chlorides according to one embodiment of this disclosure satisfies Formula 3 above. That is, the contact angle hysteresis (CAH) can be 25° or greater, 26° or greater, or 28° or greater, and 60° or less, 50° or less, 40° or less, 35° or less, or 32° or less.

[0073] In one embodiment of this disclosure, the substrate may be stainless steel (e.g., SUS and STS) or glass, but is not limited thereto.

[0074] Figure 1 This is a schematic diagram illustrating the process of forming salt arches on the surface of a coating according to one embodiment of the present disclosure.

[0075] When the receding contact angle, contact angle hysteresis, and the ratio of receding contact angle to contact angle hysteresis satisfy Equations 1 to 3 according to one embodiment of this disclosure, the inorganic chloride solution adheres to the surface of the coating to form droplets and dries.

[0076] More specifically, refer to Figure 1 As droplets of the inorganic chloride solution attached to the surface of the coating dry, solid salt is generated from the edge along the boundary between the droplet and the air. As the droplets continue to dry, the salt continues to grow along the boundary of the droplets, and droplets retained inside continue to be absorbed into the salt arch and evaporate to the outside, eventually forming a salt arch, which is a hollow arch made of salt.

[0077] Meanwhile, when certain conditions of Formulas 1 to 3 according to one embodiment of this disclosure are met, the formed salt arch retains its shape on a flat surface. However, when the surface is tilted (e.g., about 45 degrees), it easily detaches without strong external force and leaves no residue, making removal very easy.

[0078] The scale-inhibiting coatings for inorganic chlorides disclosed herein are not limited to coatings with specific components. If the coating simultaneously satisfies Formulas 1 to 3, then regardless of the coating's structure, composition, manufacturing method, etc., chlorides form salt arches during adhesion and drying on the coating surface, which can provide an easily removable effect.

[0079] When the retreat contact angle (REC) with water is 80° or less, the salt or solution inside the droplet does not migrate to the outside but tends to remain in contact with the coating. During this process, the salt component may remain on the surface of the coating upon drying. On the other hand, when the REC is too large (above 150°), the droplet dries in a nearly spherical shape, and the solution inside the droplet, rather than the solution near the surface, continues to migrate to the outside, causing the solution near the surface to evaporate in the latter part of the drying process. Therefore, salt may remain in the portion of the droplet that is in contact with the surface and may not form a salt arch.

[0080] Furthermore, when the contact angle hysteresis (CAH) is less than 25°, the interface between the droplet and the surface in the salt arch is not fixed and tends to move freely. Therefore, as the droplet dries, the droplet interface may gradually move into the interior of the salt arch. Consequently, the size of the arch itself gradually decreases during the drying process, and the arch becomes clumped together, making it impossible to maintain the shape of the salt arch.

[0081] Therefore, in order to maintain the shape of the salt arch without leaving any salt components on the surface of the coating, each of REC and CAH needs to be above a certain level. However, when the REC to CAH ratio is too high, the shape of the salt arch may deform during the drying process, making it difficult to maintain the shape of the salt arch after drying.

[0082] Therefore, the ratio of REC to CAH is also important for the formation and retention of the salt arch, so that when the conditions of Equations 1 to 3 are met simultaneously, the shape of the salt arch is maintained during the drying process of the droplet while no salt component can remain on the surface of the coating.

[0083] Figure 2 A cross-sectional view of a salt arch according to one embodiment of this disclosure is shown schematically. Figure 2 In this context, Ro is the outer radius of the salt arch, Ri is the inner radius of the salt arch, and h is the height of the salt arch.

[0084] Reference Figure 2 When the ratio of the height of the salt arch to its outer radius (Ro) is 0.5 or greater (h / Ro≥0.5), and the area of ​​the empty space at the contact surface between the salt arch and the surface is 50% or greater (Ri) 2 / Ro 2 When the value is ≥0.5, it can be considered that a salt arch as defined in this disclosure has been formed.

[0085] on the contrary, Figure 3 A schematic diagram illustrating the process by which salt arches are not formed on the surface of a coating according to a comparative example of this disclosure, and Figure 4This is a schematic diagram illustrating the process by which salt arches are not formed on the surface of a substrate according to a comparative example of the present disclosure.

[0086] Reference Figure 3 Initially, as droplets of the inorganic chloride solution attached to the surface of the coating dry, similar to the present disclosure, salt can be generated from the edges along the boundary between the droplets and the air. However, if one or more of the conditions of Formulas 1 to 3 according to an embodiment of the present disclosure are not met, the shape of the salt arch cannot be formed as the droplets continue to dry, resulting in an incomplete or deformed arch. Therefore, the salt component remains irregularly attached to the surface.

[0087] Figure 4 This illustrates the adhesion of droplets of an inorganic chloride solution to a surface with a coating (e.g., SUS) having a small contact angle. The salts generated during the droplet drying process do not form an arch shape at all, but rather spread across the entire surface and adhere firmly, making them difficult to remove and causing fouling.

[0088] Figure 5 Photographs of a salt arch (A) according to one embodiment of the present disclosure and comparative arches (B, C) are shown.

[0089] exist Figure 5 In the images, (A) is a photograph of a fully formed salt arch removed from a surface according to one embodiment of the present disclosure, (B) is a photograph of an incompletely formed arch, and (C) is a photograph of chloride dispersed and attached to a surface without forming an arch.

[0090] The anti-fouling coating for inorganic chlorides that satisfies the above characteristics includes, for example, a first coating comprising a cured product of alkyl-trialkoxysilane and tetraalkoxysilane; and a second coating formed on the first coating and comprising a cured product of fluorinated polyether silane, but is not limited thereto.

[0091] Alkyl-trialkoxysilanes can be compounds represented by the following chemical formula 1.

[0092] [Chemical Formula 1]

[0093] R 11 -Si(R 12 (R) 13 (R) 14 )

[0094] In chemical formula 1,

[0095] R 11 Alkyl groups having 1 to 5 carbon atoms, and

[0096] R 12 To R 14Each is an alkoxy group having 1 to 5 carbon atoms.

[0097] According to one embodiment of this disclosure, the tetraalkoxysilane can be a compound represented by the following chemical formula 2.

[0098] [Chemical Formula 2]

[0099] Si(R 21 (R) 22 (R) 23 (R) 24 )

[0100] In chemical formula 2,

[0101] R 21 To R 24 Each is an alkoxy group having 1 to 5 carbon atoms.

[0102] According to one embodiment of this disclosure, based on 100 parts by weight of alkyl-trialkoxysilane, the first coating solution may contain 1 to 50 parts by weight of tetraalkoxysilane.

[0103] According to one embodiment of this disclosure, based on 100 parts by weight of alkyl-trialkoxysilane, the first coating solution may contain 1 to 10 parts by weight of organic acid.

[0104] According to one embodiment of this disclosure, the fluoropolyether silane can be a compound comprising a portion represented by the following chemical formulas 3-1 to 3-4.

[0105] [Chemical Formula 3-1]

[0106] CF3-

[0107] [Chemical Formula 3-2]

[0108] -CF2-CF2-O-

[0109] [Chemical Formula 3-3]

[0110] -CF2-CF2-CF2-O-

[0111] [Chemical Formula 3-4]

[0112] -Si(R 31 (R) 32 (R) 33 )

[0113] In chemical formula 3-4,

[0114] R 31 To R 33 Each is an alkoxy group having 1 to 5 carbon atoms.

[0115] According to one embodiment of this disclosure, the curing of the first coating solution and the curing of the second coating solution can be carried out independently at a temperature of 100°C to 150°C.

[0116] According to one embodiment of this disclosure, the cured thickness of the first coating can be from about 0.1 μm to about 100 μm, more preferably from about 1 μm to about 50 μm, or from about 2 μm to about 10 μm. When the cured thickness of the first coating is within the above range, cracking can be prevented while maintaining appropriate coating hardness.

[0117] Furthermore, the cured thickness of the second coating can be from about 1 nm to about 100 nm, or from about 5 nm to about 50 nm. Specifically, the second coating can be in a state in which the fluorinated polyether silane contained in the second coating solution is applied as a substantially monolayer. When the cured thickness of the second coating is within the above range, a uniform coating and an appropriate surface energy level can be maintained.

[0118] According to one aspect of this disclosure, it can be formed by a method comprising: applying a first coating solution comprising an alkyl-trialkoxysilane, a tetraalkoxysilane, and an organic acid; curing the applied first coating solution to form a first coating; applying a second coating solution comprising a fluorinated polyether silane onto the first coating; and curing the applied second coating solution to form a second coating.

[0119] In one embodiment of the method according to this disclosure, a first coating solution comprising alkyl-trialkoxysilane, tetraalkoxysilane and organic acid is first applied to the surface of a substrate.

[0120] According to one embodiment of this disclosure, alkyl-trialkoxysilanes can be compounds represented by the following chemical formula 1.

[0121] R 11 -Si(R 12 (R) 13 (R) 14 )

[0122] In chemical formula 1,

[0123] R 11 Alkyl groups having 1 to 5 carbon atoms, and

[0124] R 12 To R 14 Each is an alkoxy group having 1 to 5 carbon atoms.

[0125] More specifically, R 11 It can be methyl, ethyl, propyl, butyl, or pentyl, and can be straight-chain or branched.

[0126] R 12 To R 14 Each can be independently methoxy, ethoxy, propoxy, butoxy, or pentoxy, and can be straight-chain or branched.

[0127] Specifically, the alkyl-trialkoxysilane can be, for example, selected from at least one of the following: methyl-trimethoxysilane, methyl-triethoxysilane, methyl-tripropoxysilane, methyl-tributoxysilane, methyl-tripentoxysilane, ethyl-trimethoxysilane, ethyl-triethoxysilane, ethyl-tripropoxysilane, ethyl-tributoxysilane, ethyl-tripentoxysilane, propyl-trimethoxysilane, propyl-triethoxysilane, propyl-tripropoxysilane, propyl-tributoxysilane, propyl-tripentoxysilane, butyl-trimethoxysilane, butyl-triethoxysilane, butyl-tripropoxysilane, butyl-tributoxysilane, butyl-tripentoxysilane, pentyl-trimethoxysilane, pentyl-triethoxysilane, pentyl-tripropoxysilane, pentyl-tributoxysilane, and pentyl-tripentoxysilane.

[0128] The aforementioned alkyl-trialkoxysilane is a component in the composition that forms the main network of the inorganic coating film via a sol-gel reaction. Here, the alkyl group can increase the flexibility of the network structure and eliminate stress generated during reactions between silanols or between silanols and metal oxide layers on the substrate surface. When only alkylsilanes are used, the amount of silanols participating in the reaction is small, which is detrimental to reducing surface energy during subsequent fluorine coating, and when only alkoxysilanes are used, it may be difficult to achieve the aforementioned stress-relief effect.

[0129] According to one embodiment of this disclosure, the tetraalkoxysilane can be a compound represented by the following chemical formula 2.

[0130] [Chemical Formula 2]

[0131] Si(R 21 (R) 22 (R) 23 (R) 24 )

[0132] In chemical formula 2,

[0133] R 21 To R 24 Each is an alkoxy group having 1 to 5 carbon atoms.

[0134] More specifically, R 21 To R 24 Each can be independently methoxy, ethoxy, propoxy, butoxy, or pentoxy, and can be straight-chain or branched.

[0135] Specifically, the tetraalkoxysilane can be, for example, at least one selected from tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and tetrapentoxysilane.

[0136] As described above, tetraalkoxysilanes can increase the number of silanol groups in the composition that can participate in reactions between the aforementioned silanols or between silanols and metal oxide layers on the surface of the substrate, and this helps to achieve a surface with low surface energy by increasing reactivity with fluorosilanes in subsequent processes.

[0137] When alkyl-trialkoxysilanes and tetraalkoxysilanes are used in appropriate ratios, the problem of cracking throughout the coating network can be prevented, and an appropriate amount of silanol reactive groups can be provided on the surface.

[0138] According to one embodiment of this disclosure, the organic acid can be a carboxylic acid having 1 to 5 carbon atoms.

[0139] Specifically, the organic acid can be, for example, at least one selected from formic acid, acetic acid, and propionic acid.

[0140] The aforementioned organic acids are used as catalysts to promote the hydrolysis of silane groups in the composition and can play a role in determining the overall network structure. Under acidic conditions with low pH, the hydrolysis rate is superior to the condensation reaction rate, thus the silane bonds form a linear structure. On the other hand, under alkaline conditions, the condensation reaction rate is faster, resulting in a particulate structure. Inorganic acids, such as hydrochloric acid, can also be used instead of organic acids, but organic acids can be more useful in controlling the gelation time.

[0141] According to one embodiment of this disclosure, based on 100 parts by weight of alkyl-trialkoxysilane, the first coating solution may contain about 1 to 50 parts by weight of tetraalkoxysilane.

[0142] When using tetraalkoxysilanes within the above range, it is beneficial to achieve appropriate surface energy and excellent adhesion.

[0143] According to one embodiment of this disclosure, based on 100 parts by weight of alkyl-trialkoxysilane, the first coating solution may contain about 1 part by weight to about 10 parts by weight of organic acid.

[0144] When organic acids within the above range are used, a linear network structure can be obtained at an appropriate hydrolysis rate, and the mechanical properties of the coating can be maintained.

[0145] The pH of the first coating solution may be about 7 or less, about 5 or less, or about 3 or less, and about 1 or more, or about 2 or more.

[0146] pH can affect the hydrolysis rate and the condensation reaction rate, and the difference between these two reaction rates determines the structure of the coated film. Furthermore, pH affects the storage stability of the prepared coating solution.

[0147] From this perspective, stable inorganic coating films can be obtained under acidic conditions with a pH range as described above.

[0148] In addition to the components mentioned above, the first coating solution may also contain an organic solvent. Such an organic solvent may specifically include alcohols or ethers, and the amount of organic solvent may be appropriately selected taking into account the coating and subsequent drying.

[0149] When the first coating solution is applied to the surface of the substrate, the applied thickness can be from about 0.1 μm to about 100 μm, more preferably from about 1 μm to about 50 μm, or from about 2 μm to about 10 μm, depending on the thickness after drying and curing. When the cured thickness of the first coating is within the above range, cracking can be prevented while maintaining appropriate coating hardness.

[0150] There are no particular limitations on the application method, and methods commonly used in the technical field to which this invention pertains can be selected, such as applying directly with a tool such as a brush, spraying after adjusting the viscosity appropriately, or coating with a stick.

[0151] After application, drying can be carried out at room temperature for approximately 10 minutes to approximately 1 hour. These drying conditions can vary depending on the type and amount of solvent used.

[0152] After drying, it can be cured at a temperature of about 100°C to about 150°C for about 30 minutes to about 2 hours.

[0153] During the curing process, a sol-gel reaction can be carried out between the alkyl-trialkoxysilane and the silane group in the tetraalkoxysilane compound in the first coating solution to form the first coating.

[0154] According to one embodiment of this disclosure, the fluoropolyether silane can be a compound comprising a portion represented by the following chemical formulas 3-1 to 3-4.

[0155] [Chemical Formula 3-1]

[0156] CF3-

[0157] [Chemical Formula 3-2]

[0158] -CF2-CF2-O-

[0159] [Chemical Formula 3-3]

[0160] -CF2-CF2-CF2-O-

[0161] [Chemical Formula 3-4]

[0162] -Si(R 31 (R) 32 (R) 33 )

[0163] In chemical formula 3-4,

[0164] R 31 To R 33 Each is an alkoxy group having 1 to 5 carbon atoms.

[0165] The aforementioned fluorinated polyether silane is a compound having a fluorocarbon group at one end, an alkoxysilane group at the other end, and a fluoroethoxy or fluoropropoxy group in the middle. It can form a hard coating by directly forming covalent bonds with the first coating, and the surface energy of the coating can be greatly reduced due to the large number of fluorine chains.

[0166] In the second coating solution, fluoropolyether silanes can be used with alkoxyfluoroalkyl-based solvents.

[0167] The alkoxyfluoroalkyl solvents used in this article can be ether compounds represented by the following chemical formula 4.

[0168] CF3-(CF2)nO-(CH2)m-CH3

[0169] In the chemical formula, n and m can each be an integer from 1 to 5 independently.

[0170] In the ether compound, an alkyl group without fluorine substitution is attached to one side of the oxygen atom, and an alkyl group in which all hydrogen atoms are fluorine-substituted is attached to the other side of the oxygen atom.

[0171] Such ether compounds exhibit excellent compatibility with the aforementioned fluorinated polyether silane compounds and can uniformly disperse the fluorinated polyether silane compounds in the second coating solution.

[0172] When the second coating solution is applied to the surface of a substrate on which the first coating has been formed, the applied thickness can be from about 1 nm to about 100 nm. Specifically, the second coating can be in a state where the fluoropolyether silane contained in the second coating solution is applied as a substantially monolayer. When the cured thickness of the second coating is within the above range, a uniform coating and an appropriate surface energy level can be maintained.

[0173] There are no particular limitations on the application method, and methods commonly used in the technical field to which this invention pertains can be selected, such as applying directly with a tool such as a brush, spraying after adjusting the viscosity appropriately, or coating with a stick.

[0174] After application, drying can be carried out at room temperature for approximately 10 minutes to approximately 1 hour. These drying conditions can vary depending on the type and amount of solvent used.

[0175] After drying, it can be cured at a temperature of about 100°C to about 150°C for about 30 minutes to about 2 hours.

[0176] During the curing process, the fluorinated polyether silane in the second coating solution interacts with the functional groups contained in the first coating to form the second coating.

[0177] According to one embodiment of this disclosure, the cured thickness of the first coating can be from about 0.1 μm to about 100 μm.

[0178] Furthermore, the cured thickness of the second coating can be from about 1 nm to about 100 nm.

[0179] Since the anti-scaling coating against inorganic chlorides provided by one embodiment of the present disclosure as described above satisfies Formulas 1 to 3, it forms a salt arch shape when droplets of inorganic chloride solution adhere to it. This salt arch is easily removed and can prevent surface contaminants or dirt caused by inorganic chlorides, thus providing excellent anti-scaling effects for a variety of products.

[0180] The functions and effects of the present invention will be described in more detail below through specific embodiments. However, these embodiments are for illustrative purposes only, and the present invention is not intended to be limited by these embodiments.

[0181] <Example>

[0182] Example 1

[0183] First coating solution

[0184] Mix 5 parts by weight of methyl-trimethoxysilane as the alkyl-trialkoxysilane component, 1 part by weight of tetraethoxysilane as the tetraalkoxysilane component, and 4 parts by weight of a 6% acetic acid solution diluted in water (pH: approximately 2.3).

[0185] The first coating solution is prepared by diluting 100 parts by weight of the above coating solution with about 50 parts by weight of isopropanol as a solvent.

[0186] Second coating solution

[0187] As a fluoropolyether silane component, Optool-DSX (a perfluoropolyether-silane manufactured by Daikin) is used by dissolving Optool-DSX at a concentration of 1% by weight in a solvent (Novec-7200 manufactured by 3M).

[0188] Formation of scale-inhibiting coatings against inorganic chlorides

[0189] The first coating solution was applied to the surface of a stainless steel substrate (316 stainless steel, 10cm x 10cm) using a brush, dried at room temperature for about 30 minutes, and then cured at a temperature of about 130°C for about 1 hour to form a first coating with a thickness of about 5μm.

[0190] Apply the second coating solution to the first coating using a brush, dry at room temperature for about 30 minutes, and then cure at a temperature of about 130°C for about 1 hour to form a second coating with a thickness of about 10 nm.

[0191] Example 2

[0192] The anti-scaling coating against inorganic chlorides was formed in the same manner as in Example 1, except that in the second coating solution of Example 1, Optool-DSX (perfluoropolyether-silane manufactured by Daikin) was used by dissolving Optool-DSX at a concentration of 0.1% by weight in a solvent (Novec-7200 manufactured by 3M).

[0193] Comparative Example 1

[0194] The same stainless steel substrate as in Example 1 was used as Comparative Example 1.

[0195] Comparative Example 2

[0196] After thoroughly cleaning the slides with isopropanol and acetone and allowing them to dry completely, apply 20 cst silicone oil (DMS-T12, manufactured by Gelest) to the front side of the slides using a brush. Place the slides upright for approximately one hour to remove excess oil from the surface, then react at 130°C for 24 hours. After the reaction, wash away any remaining silicone oil with isopropanol and acetone.

[0197] Comparative Example 3

[0198] Using the Sylgard 184 elastomer kit (Dow Corning), mix 10 parts by weight of the base material and 1 part by weight of the hardener, and remove air bubbles. Pour the mixture into petri dishes to a thickness of 5 mm and cure in an oven at 70°C for 3 hours.

[0199] Comparative Example 4

[0200] A super water-repellent coating was prepared using Neverwet spray (Rust-Oleum Corporation) (a commercial super water-repellent coating product). First, a Neverwet base coat was applied to the SUS substrate and dried at room temperature for 1 hour. A Neverwet top coat was then applied over the first coat and dried at 70°C for 1 hour.

[0201] Comparative Example 5

[0202] The S.PDMS1 solution of Example 7 of Korean Patent Publication No. 2015-0033725 was prepared and coated on a stainless steel substrate (stainless steel 316, 10cm×10cm), and then cured at 120°C for 3 hours.

[0203] Comparative Example 6

[0204] Mix 90.9 parts by weight of Dow's Sylgard 184 silicone elastomer kit base resin and 9.1 parts by weight of Dow's Sylgard 184 silicone elastomer kit crosslinking agent, and remove air bubbles. Apply to the surface of a stainless steel substrate (stainless steel 316, 10cm × 10cm) and cure at 120°C for 3 hours.

[0205] Comparative Example 7

[0206] Mix 45 parts by weight of Dow's Sylgard 184 silicone elastomer kit base resin, 4.5 parts by weight of Dow's Sylgard 184 silicone elastomer kit crosslinking agent, and 50.5 parts by weight of silicone oil (manufactured by Gelest, product name: DMS-T11), and remove air bubbles. Apply the mixture to the surface of a stainless steel substrate (stainless steel 316, 10cm × 10cm) and cure at 120°C for 3 hours.

[0207] Comparative Example 8

[0208] The sample prepared in Comparative Example 7 was immersed in DMS-T11 (Mw: 1,250 g / mol) silicone oil at room temperature for 24 hours, then removed and placed vertically for 30 minutes to remove residual oil from the surface.

[0209] [Table 1]

[0210]

[0211] In Table 1,

[0212] ADV is the forward contact angle of water at 25°C (unit: °).

[0213] REC is the receding contact angle of water at 25°C (unit: °), and

[0214] CAH stands for contact angle hysteresis, which is the difference between the forward contact angle (in °) and the backward contact angle (in °) of water at 25°C.

[0215] <Experimental Example>

[0216] (1) Confirmation of the formation of the salt arch

[0217] 400 g of KCl (99.0%, DUKSAN pure chemicals co.) was completely dissolved in 1 kg of distilled water at 80 °C and cooled to room temperature at 25 °C. The remaining solution after KCl precipitation was then used as a saturated KCl solution. To evaluate the KCl salt arches, 50 μL of the saturated KCl solution was pipetted to 10 different points on the sample surface. After drying in an oven at 60 °C for 12 hours, the shape of the salt arches was examined.

[0218] After drying, observe whether an arch has formed on the surface with a height-to-outer radius (Ro) ratio of 0.5 or greater (h / Ro≥0.5) and whether the empty space area at the contact surface between the salt arch and the surface is 50% or greater (Ri). 2 / Ro 2 Salt arches with a diameter of ≥0.5.

[0219] If a salt arch that meets the above conditions is formed, it is evaluated as O. If an arch that is an incomplete salt arch that does not meet the above conditions is formed, or if chloride is dispersed and adhered to the surface without an arch shape, it is evaluated as X.

[0220] (2) Confirmation of salt arches or chloride adhesion

[0221] After observing the formation of salt arches in (1), the number of salt arches (or chloride deposits (if no salt arches are formed) falling from the surface when tilted such that the angle between the surface and the ground is 45° is measured and evaluated as follows.

[0222] O: Four or more salt domes or attachments are present.

[0223] △: Attached with one to three salt domes or deposits

[0224] X: Salt arch or all attachments have fallen off.

[0225] (3) Residue

[0226] After assessing whether salt arches are attached in (2), if there are no visible residues on the surface of the salt arches or areas where the attachments have been removed, it is assessed as X, and if residues remain, it is assessed as O.

[0227] (4) Scratch resistance

[0228] For the surfaces of the coatings in the embodiments and comparative examples, the area per unit area (cm²) 2 0.1 g of potassium chloride was placed between the surfaces of the two substrates, and then subjected to 1000 N / m 2 The surface was subjected to 100 reciprocating motions of 1 cm under a load. After the scratch test, if no scratches were observed on the surface with the naked eye, it was rated as O, and if scratches appeared, it was rated as X.

[0229] [Table 2]

[0230]

[0231] Referring to Table 2, in Examples 1 and 2 where all Formulas 1 to 3 are satisfied on the surface of the coating, salt arches are formed as the chloride adhering to the surface dries, and the formed salt arches are easily detached without excessive external force. Therefore, it is evaluated as very effective in preventing chloride scaling because no residue is left.

[0232] On the other hand, in comparative examples that do not satisfy any or more of Formulas 1 to 3, no salt arches are formed (Comparative Examples 1 to 8) or deposits remain on the surface (Comparative Examples 1, 4 to 8) under the same conditions as the examples, and therefore there is almost no anti-chloride scale effect.

Claims

1. A scale-preventing product, comprising: Base; and An anti-scaling coating against inorganic chlorides is disposed on at least one side of the substrate. The scale-inhibiting coating for preventing inorganic chlorides described herein satisfies the following formulas 1 to 3: [Formula 1] 80° <REC<150° [Equation 2] 4≥REC / CAH≥2.5 [Formula 3] CAH≥25° In equations 1 to 3, REC is the receding contact angle with water (unit: °), and CAH stands for contact hysteresis, which is the difference between the advancing contact angle (in °) and the receding contact angle (in °) with respect to water. The scale-inhibiting coating for preventing inorganic chlorides includes: A first coating comprising a cured product containing alkyl-trialkoxysilanes and tetraalkoxysilanes; as well as A second coating is formed on the first coating and contains a cured product of fluorinated polyether silane.

2. The anti-scaling product according to claim 1, In Equation 2, the REC / CAH is 3.5 or less.

3. The anti-scaling product according to claim 1, In Equation 1, REC is 85° or greater.

4. The anti-scaling product according to claim 1, In Equation 3, CAH is 60° or less.

5. The anti-scaling product according to claim 1, The alkyl-trialkoxysilane mentioned above is a compound represented by the following chemical formula 1: [Chemical Formula 1] R 11 -Si(R 12 )(R 13 )(R 14 ) In chemical formula 1, R 11 Alkyl groups having 1 to 5 carbon atoms, and R 12 To R 14 Each is an alkoxy group having 1 to 5 carbon atoms.

6. The anti-scaling product according to claim 1, The tetraalkoxysilane mentioned therein is a compound represented by the following chemical formula 2: [Chemical Formula 2] Si(R 21 )(R 22 )(R 23 )(R 24 ) In chemical formula 2, R 21 To R 24 Each is an alkoxy group having 1 to 5 carbon atoms.

7. The anti-scaling product according to claim 1, The fluoropolyether silane mentioned above is a compound containing groups represented by the following chemical formulas 3-1 to 3-4: [Chemical Formula 3-1] CF3- [Chemical Formula 3-2] -CF2-CF2-O- [Chemical Formula 3-3] -CF2-CF2-CF2-O- [Chemical Formula 3-4] -Si(R 31 )(R 32 )(R 33 ) In chemical formula 3-4, R 31 To R 33 Each is an alkoxy group having 1 to 5 carbon atoms.

8. The anti-scaling product according to claim 1, The substrate is stainless steel.

Images