Wet coating agent for vehicle and method for preparing same

Abstract

Disclosed are a wet coating agent for a vehicle with which the surface of a vehicle is conveniently coated by being sprayed onto the vehicle and being rinsed with high-pressure water, and a method for preparing the same. The wet coating agent for a vehicle contains decamethylcyclopentasiloxane, purified water, an alcohol-based nonionic surfactant, amodimethicone oil, and a fluorinated silane.

Description

WET COATING AGENT FOR VEHICLE AND METHOD FOR PREPARING SAME

[0001] The present disclosure relates to a wet coating agent for a vehicle and a method for preparing the same, and more particularly, to a wet coating agent for a vehicle, with which the surface of a vehicle may be conveniently coated, and a method for preparing the same.

[0002] Unless otherwise indicated herein, the contents in this Background Art section are not prior art to the claims of the present application, and inclusion in this section is not admitted to be the prior art.

[0003] The paint coating on the surface of a vehicle is easily contaminated and damaged because it is continuously exposed to foreign substances generated on the road, changes in external temperature and humidity, and snow and rain caused by climate change.

[0004] Recently, a gloss coating has been applied to the painted surface of a vehicle to prevent contamination of or damage to the painted surface, but the demand for self-coating of the painted surface has increased due to the high coating cost and low service reliability versus the cost.

[0005] However, since the operation of coating the vehicle's painted surface with existing coating agents is highly difficult, there is a need to develop a product with which the vehicle's painted surface can be coated conveniently and easily by non-professional users.

[0006] In this regard, Korean Patent No. 10-2508223 discloses a gloss coating agent for a vehicle with enhanced cleaning and coating functions and a method for preparing the same, and Korean Patent No. 10-2482458 discloses a gloss coating agent and a method for preparing the same.

[0007] However, existing inventions do not disclose wet coating agent-related technologies that enable even users with insufficient coating experience to conveniently coat the surface of a vehicle with a coating agent.

[0008] The present disclosure is intended to provide a wet coating agent for a vehicle, with which the surface of a vehicle is conveniently coated by being sprayed onto the vehicle and being rinsed with high-pressure water, and a method for preparing the same.

[0009] In addition, it is obvious that the technical problems to be solved by the present disclosure are not limited to the technical problems described above, and that other technical problems may be inferred from the following description.

[0010] According to one embodiment of the present disclosure, a wet coating agent for a vehicle contains decamethylcyclopentasiloxane, purified water, an alcohol-based nonionic surfactant, amodimethicone oil, and a fluorinated silane.

[0011] In addition, the wet coating agent for a vehicle may contain 1 to 5 wt% of the decamethylcyclopentasiloxane, 43 to 78 wt% of the purified water, 5 to 10 wt% of the alcohol-based nonionic surfactant, 40 to 50 wt% of the amodimethicone oil, and 0.5 to 2 wt% of a fluorinated alkoxysilane.

[0012] According to another embodiment of the present disclosure, a method for preparing a wet coating agent for a vehicle includes: a first stirring step of stirring decamethylcyclopentasiloxane, purified water, an alcohol-based nonionic surfactant, and amodimethicone oil, thereby preparing a first mixture; a second stirring step of adding a fluorinated silane to the first mixture, thereby preparing a second mixture; and a third stirring step of adding purified water to the second mixture, thereby preparing a third mixture.

[0013] In addition, the first stirring step may include stirring 1 to 5 wt% of the decamethylcyclopentasiloxane, 42 to 55 wt% of the purified water, 5 to 10 wt% of the alcohol-based nonionic surfactant, and 40 to 50 wt% of the amodimethicone oil.

[0014] In addition, the second stirring step may include adding 0.5 to 2 wt% of the fluorinated alkoxysilane, followed by stirring.

[0015] In addition, the third stirring step may include additionally adding 1 to 23 wt% of the purified water, followed by stirring.

[0016] In addition, the fluorinated alkoxysilane may be trifluoropropyltrimethoxysilane.

[0017] According to one embodiment disclosed in the present specification, the vehicle surface on which water remains may be coated with the wet coating agent for a vehicle simply by spraying onto the vehicle surface and rinsing with high-pressure water, thereby improving slickness, slipperiness, and antifouling properties of the vehicle surface maintaining the original color and transparency of the vehicle surface.

[0018] In addition, the wet coating agent for a vehicle has the advantage of being effective in protecting the surfaces of various parts attached to the vehicle because not only the vehicle surface but also the surfaces of wheels, glass, metals, and polymer materials attached to the vehicle may be coated with the wet coating agent.

[0019] In addition, the wet coating agent for a vehicle forms a coating layer by coating the vehicle surface therewith, and the coating layer has the advantage of improving the slickness, slipperiness, hydrophobicity, and water-repellent properties of the vehicle surface while maintaining the vehicle's original color and transparency.

[0020] In addition, the wet coating agent for a vehicle has the advantage of forming a coating layer not only on the painted surface of the vehicle but also on all parts of the vehicle, including wheels, glass, metal, and polymer exterior materials.

[0021] In addition, since the above-described effects of the present disclosure described are to be naturally exerted by the configuration of the contents described irrespective of whether or not the inventor recognizes such effects, the above-described effects are only a few effects according to the contents described, and it should not be recognized that all the effects which are understood by the inventor are actually described herein. In addition, the effects of the present disclosure will be further understood by the entire description of the present specification, and if those having ordinary knowledge in the art to which the present disclosure pertains recognize such effects through the present specification even if the effects are not described explicitly, the effects will be recognized as being described in the present specification.

[0022] FIG. 1 is a flow chart showing a method for preparing a wet coating agent for a vehicle according to one embodiment of the present disclosure.

[0023] FIG. 2 shows components contained in a first mixture obtained in the first stirring step of the method for preparing a wet coating agent for a vehicle shown in FIG. 1.

[0024] FIG. 3 shows components contained in each of the second and third mixtures obtained in the second and third stirring steps of the method for preparing a wet coating agent for a vehicle shown in FIG. 1.

[0025] FIG. 4 schematically shows a state in which contact angle measurement is performed to analyze the degree of hydrophilicity of a coating layer formed on the vehicle surface using the wet coating agent for a vehicle prepared by the method shown in FIG. 1.

[0026] Hereinafter, the configuration, operation, and effect of a wet coating agent for a vehicle and a method for preparing the same according to preferred embodiments will be described with reference to the accompanying drawings. For reference, in the drawings, each component is omitted or schematically illustrated for convenience and clarity of illustration, and the size of each component does not completely reflect a real size. Further, like reference numerals are used to indicate like components throughout the drawings. In the individual drawings, reference numerals for the same components will be omitted.

[0027] Referring to FIGS. 1 to 3, the wet coating agent for a vehicle contains decamethylcyclopentasiloxane, purified water, an alcohol-based nonionic surfactant, amodimethicone oil, and a fluorinated alkoxysilane.

[0028] Fluorinated alkoxysilane is a compound, a kind of fluorinated silane, and examples of fluorinated silane include 3,3,3-trifluoropropyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane (trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane), heptadecafluorodecyltriisopropoxysilane, fluorine-containing chlorosilane compounds, perfluorinated alkylsilane compounds, perfluorinated methacrylate compounds, perfluorinated sulfonyl chloride compounds, and perfluorinated sulfonic acid.

[0029] The wet coating agent for a vehicle is sprayed onto the vehicle surface on which water remains or from which water has been removed, and then spreads on the vehicle surface by high-pressure water to form a coating layer on the surface of the vehicle, and the coating layer improves the water repellency, slickness, hydrophobicity, slipperiness, durability, and anti-fouling properties of the vehicle surface.

[0030] As the hydrophobicity or water repellency of the coating layer increases, when water comes into contact with the surface of the coating layer, a phenomenon occurs in which the water is not dispersed by the surface tension of the coating layer surface but is repelled by the coating layer.

[0031] As the slickness and slipperiness of the coating layer increase, the surface friction of the coating layer decreases, and even if contaminants including dust adhere to the coating layer, the contaminants slide and are separate from the coating layer.

[0032] Decamethylcyclopentasiloxane contained in the wet coating agent for a vehicles is a low-viscosity, high-volatility silicone, and has the advantages of improving the hydrophobicity or water-repellency of the wet coating agent for a vehicle applied to the vehicle due to its low surface tension, reducing the coefficient of friction, and increasing the coating work speed through its high volatility.

[0033] In addition, the amodimethicone oil contained in the wet coating agent for a vehicle is a silicone-based polymer having an amino functional group as an end group, and has the advantage of protecting the surface of the vehicle by being contained in the coating layer formed when the wet coating agent for a vehicle is sprayed onto the vehicle surface.

[0034] In addition, the fluorinated alkoxysilane contained in the wet coating agent for a vehicle has the advantage of improving the slickness, hydrophobicity, water repellency, and slipperiness of the coating layer formed on the vehicle surface the low surface energy of fluorine itself.

[0035] Fluorine has a high electron density, the smallest atomic radius after the hydrogen atom, and high electronegativity, and thus forms a strong carbon-fluorine bond. Due to these properties of fluorine, monomers containing perfluorinated alkyl groups exhibit extremely hydrophobic properties with a critical surface tension of 5 to 10 dynes / cm.

[0036] In addition, fluorine-coated products have the advantages of being less affected by the chemical environment, having high heat resistance, insulation, surface resistivity, wear resistance, acid resistance and alkali resistance, and being easily cleaned.

[0037] Referring to FIG. 1, a method (100) for preparing a wet coating agent for a vehicle includes: a first stirring step (S110) of mixing and stirring decamethylcyclopentasiloxane, purified water, an alcohol-based nonionic surfactant, and amodimethicone oil, thereby preparing a first mixture; a second stirring step (S120) of adding a fluorinated alkoxysilane, followed by stirring; and a third stirring step (S130) of adding purified water, followed by stirring.

[0038] Meanwhile, the method (100) for preparing a wet coating agent for a vehicle may further include a nitrogen charging step (S105), and the nitrogen charging step (S105) is performed before the first stirring step (S110) is performed.

[0039] Specifically, the nitrogen charging step (S105) is a step of introducing nitrogen (N2) gas into a reaction vessel having a reaction space formed therein to fill the interior of the reaction vessel with nitrogen, and when the reaction space is filled with nitrogen, the introduction of nitrogen is stopped.

[0040] In the first stirring step (S110), 1 to 5 wt% of decamethylcyclopentasiloxane, 42 to 55 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, and 40 to 50 wt% of amodimethicone oil are stirred in the reaction vessel, thereby preparing a first mixture (step S110).

[0041] Specifically, in the first stirring step (S110), 1 to 5 wt% of decamethylcyclopentasiloxane, 42 to 55 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, and 40 to 50 wt% of amodimethicone oil are stirred at 50 to 100 rpm for 9.5 to 18.5 hours (step S110).

[0042] Referring to FIGS. 1 and 3, in the second stirring step (S120), 0.5 to 2 wt% of trifluoropropyltrimethoxysilane (TFPTMS), which is one of the fluorinated alkoxysilanes, is added to the first mixture in the reaction vessel, followed by stirring, thereby preparing a second mixture (step S120).

[0043] Specifically, in the second stirring step (S120), 0.5 to 2 wt% of trifluoropropyltrimethoxysilane (TFPTMS), which is one of fluorinated alkoxysilanes, is added to the first mixture, followed by stirring at 50 to 100 rpm for 5 to 10 hours (step S120).

[0044] Referring to FIGS. 1 and 3, in the third stirring step (S130), 1 to 23 wt% of purified water is added to the second mixture, followed by stirring, thereby preparing third mixture, and the third mixture is injected into a container or packaged, thereby preparing a wet coating agent for a vehicle (step S130).

[0045] Specifically, in the third stirring step (S130), 1 to 23 wt% of purified water is added to the second mixture, followed by stirring at 50 to 100 rpm for 3 to 8 hours, thereby preparing a third mixture (step S130).

[0046] Meanwhile, 1 to 23 wt% of purified water that is added in the third stirring step (S130) may be introduced into the reaction vessel together with 42 to 55 wt% of purified water that is introduced in the first stirring step (S110), and in this case, the content of purified water may be 43 to 78 wt%.

[0047] Decamethylcyclopentasiloxane contained in the wet coating agent for a vehicle has the advantages of improving the slickness, slipperiness, strength, and gloss durability of the coating layer formed on the vehicle surface, increasing the anti-fine scratch effect, and reducing stickiness when the coating layer comes into contact with the skin.

[0048] In addition, decamethylcyclopentasiloxane contained in the wet coating agent for a vehicles is a low-viscosity, high-volatility silicone, and has the advantages of improving the hydrophobicity or water-repellency of the wet coating agent for a vehicle applied to the vehicle due to its low surface tension, reducing the coefficient of friction, and increasing the coating work speed through its high volatility.

[0049] In addition, decamethylcyclopentasiloxane contained in the first mixture increases the auto-ignition point of the wet coating agent for a vehicle prepared in the third stirring step (S130), and increases the auto-ignition point of the coating layer formed on the vehicle surface by the wet coating agent, thereby improving the safety of the coating layer.

[0050] In addition, since silicon (Si) contained in decamethylcyclopentasiloxane has the advantage of reducing the coefficient of friction due to its low surface tension, thereby lowering the coefficient of friction of the coating layer formed on the vehicle surface by the wet coating agent containing decamethylcyclopentasiloxane.

[0051] The alcohol-based nonionic surfactant functions to enable the fluorinated alkoxysilane added in the second stirring step (S120) to be effectively mixed with purified water, and the content of the alcohol-based nonionic surfactant is preferably between 5 and 10 wt%.

[0052] In addition, the alcohol-based nonionic surfactant has the advantage of functioning to amodimethicone oil, a silicone-based polymer, and fluorinated alkoxysilane to be effectively mixed with each other.

[0053] The alcohol-based nonionic surfactant emulsifies amodimethicone oil and decamethylcyclopentasiloxane so that amodimethicone oil and decamethylcyclopentasiloxane are effectively mixed.

[0054] In addition, when the alcohol-based nonionic surfactant contained in the first mixture, the particle sizes of the amodimethicone oil and the fluorinated alkoxysilane are smaller than the particle sizes when the alcohol-based nonionic surfactant is not contained in the first mixture.

[0055] In addition, since the particle sizes of the amodimethicone oil and the fluorinated alkoxysilane are reduced, the coating layer formed by coating the vehicle surface with the wet coating agent for a vehicle prepared after the third stirring step (S130) has a uniform thickness, and the occurrence of residue or stains on the coating layer is suppressed.

[0056] In addition, since the particle sizes of the amodimethicone oil and the fluorinated alkoxysilane are reduced by the alcohol-based nonionic surfactant and stirring, even when the wet coating agent for a vehicle is applied to the vehicle surface in a state in which water or shampoo components during the vehicle washing process remain on the vehicle surface, a coating layer with excellent antifouling, hydrophobic, water-repellent, and durability properties may be formed.

[0057] For example, the general process for forming a coating layer on the surface of a vehicle includes a total of 8 steps: (1) pre-washing (high-pressure water washing), (2) applying snow foam or car shampoo to the vehicle surface, (3) cleaning with shampoo or snow foam, (4) pre-washing (high-pressure water washing), (5) removing water from the vehicle, (6) spraying a wet coating agent for vehicles, (7) wiping the hardened application area with a towel, and (8) waiting for the application area to harden for a specified period of time.

[0058] Meanwhile, the content of the alcohol-based nonionic surfactant in the first mixture is preferably 5 to 10 wt%. In this case, the particle size of the amodimethicone oil or the fluorinated alkoxysilane is relatively small, and the content of the amodimethicone oil or the fluorinated alkoxysilane is maintained at an appropriate level, so that the physical properties of the coating layer are stably maintained.

[0059] The alcohol-based nonionic surfactant contained in the first mixture is one or more of polyethylene glycol tridecyl ether and an ethoxylated propoxylated alcohol having 11 to 14 carbon atoms. Preferably, the alcohol-based nonionic surfactant is an ethoxylated propoxylated alcohol.

[0060] Amodimethicone oil is a type of siloxane polymer or silicone-based polymer having an amino functional group as an end group. The amodimethicone oil increases the solubility of various ingredients due to its excellent emulsifying properties, and at the same time, functions as an antifoaming agent, which prevents unnecessary pore formation in the coating layer and enables a relatively smooth surface to be produced.

[0061] In addition, the amodimethicone oil forms a coating layer on the vehicle surface to protect the vehicle surface from external stimuli, and it improves hydrophobicity, water repellency, and slipperiness due to the low surface tension of silicone itself. Also, the amino functional group prevents static electricity accumulation on the vehicle surface, preventing dust from sticking to the coating layer.

[0062] In addition, a substance containing the amodimethicone oil or a derivative thereof has an amine group, which is cationic in nature, and it creates steric hindrance by electrostatic force to widen the gap between particles in the coating layer, and acts as a bridge.

[0063] In addition, a substance containing the amodimethicone oil or a derivative thereof has the advantage of stably maintaining the dispersed structure of particles contained in the coating layer, and significantly increasing the dispersibility of the coating layer and the thickening effect, and is easily dispersed by high-pressure water.

[0064] In addition, as the amodimethicone oil, as a reactive amodimethicone oil that causes a dehydration condensation reaction due to hydroxyl groups (-OH) attached to both ends may be used. In the case of a coating layer formed by mixing amodimethicone oil and silicone particles together, thermal damage to the coating layer is effectively prevented.

[0065] In addition, the amodimethicone oil has excellent spreadability, and a coating layer containing the amodimethicone oil feels soft and silky, and has improved hydrophobicity, water repellency, and gloss.

[0066] In addition, in order to improve the dispersibility by the amodimethicone oil, reduce the occurrence of cracks in the coating layer, and sufficiently maintain the function of the amodimethicone oil contained in the coating layer, the content of the amodimethicone oil in the coating layer is preferably 40 to 50 wt%.

[0067] The fluorinated alkoxysilane that is used in the present disclosure is preferably any one of 3,3,3-trifluoropropyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane (trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane), and heptadecafluorodecyltriisopropoxysilane.

[0068] In addition, in the second stirring step (S120), a fluorinated silane may be added instead of the fluorinated alkoxysilane. The fluorinated silane may be any one of a fluorinated chlorosilane compound, a perfluorinated alkylsilane compound, a perfluorinated methacrylate compound, a perfluorinated sulfonyl chloride compound, or a perfluorinated sulfonic acid compound.

[0069] Specifically, the perfluorinated alkylsilane compound may be trichloro(1H,1H,2H,2H-perfluorooctyl)silane or triethyl(trifluoromethyl)silane.

[0070] In addition, the perfluorinated methacrylate compound is preferably 1H,1H-perfluorooctyl methacrylate, and the perfluorinated sulfonyl chloride compound is preferably heptadecafluoro-1-octanesulfonyl chloride.

[0071] Fluorinated alkoxysilane is used as a surface treatment agent for organic or inorganic materials, and is contained in the wet coating agent for a vehicle prepared in the third stirring step (S130) to improve the slickness, slipperiness, peelability, hydrophobicity, water repellency, and oil repellency of a coating layer formed on the vehicle surface by the wet coating agent.

[0072] Trifluoropropyltrimethoxysilane is commercially available under the trade name of DOWSIL Q3-9030 Silane, is used for coating agent synthesis, silicone polymer production, and surface treatment, and improves the slickness, hydrophobicity, water repellency, slipperiness and durability of the coating layer formed on the vehicle surface using the wet coating agent for a vehicle prepared in the third stirring step (S130).

[0073] Trifluoropropyltrimethoxysilane improves the hydrophobicity, water repellency, and slipperiness of the coating layer containing trifluoropropyltrimethoxysilane due to the low surface energy of the fluorine itself contained therein, and chemically bonds with all hydroxyl groups (-OH) existing on the painted surface of the vehicle, thereby increasing the durability of the coating layer.

[0074] In addition, the fluorinated alkoxysilane contained in the wet coating agent for a vehicle has the advantage of improving the slickness, hydrophobicity, water repellency, and slipperiness of the wet coating agent for a vehicle formed on the vehicle surface due to the low surface energy of fluorine itself contained therein.

[0075] In addition, fluorine has a high electron density, the smallest atomic radius after the hydrogen atom, and high electronegativity, and thus forms a strong carbon-fluorine bond, and due to these properties of fluorine, monomers containing a perfluorinated alkyl group exhibit extremely hydrophobic properties with a critical surface tension of 5 to 10 dynes / cm.

[0076] In addition, fluorine-coated products have the advantages of being less affected by the chemical environment, having high heat resistance, insulation, surface resistivity, wear resistance, acid resistance and base resistance, and being easily cleaned.

[0077] In the second stirring step (S120), instead of the fluorinated alkoxysilane, triethoxyoctylsilane, which is a fluorinated silane, may be added to the first mixed solution. When a wet coating agent for a vehicle containing triethoxyoctylsilane forms a coating layer on the vehicle surface, the triethoxyoctylsilane has the advantage of forming a hydrophobic layer on the vehicle surface, thereby improving the hydrophobicity, water repellency, oxidation resistance, base resistance, and corrosion resistance of the coating layer.

[0078] Referring to Table 1 below and FIG. 4, the water contact angles (shown in Table 1) of a vehicle surface 10 on which the coating layer has not been formed are values obtained by washing the vehicle surface 10, and then repeating the operation of applying a water droplet to the vehicle surface 10 and measuring the contact angle of the water droplet using a KRUSS DSA25 contact angle meter according to the ASTM D 5946 standard, a predetermined number of times.

[0079] The vehicle surface 10 on which a wet coating agent for a vehicle has not been applied and thus a coating layer has not been formed is washed through the following steps: (1) pre-washing (high-pressure water washing), (2) applying snow foam or car shampoo to the vehicle surface, (3) rinsing with shampoo or snow foam, (4) pre-washing (high-pressure water washing), and (5) removing water from the vehicle. Then, the water contact angle of the vehicle surface 10 is measured using a contact angle meter.

[0080] As a result of measuring the contact angle of a water droplet applied to the vehicle surface 10 using a contact angle meter, it can be confirmed that hydrophilicity increases in proportion to a decrease in the contact angle of the water droplet, and hydrophobicity or water repellency increases in proportion to an increase in the contact angle of the water droplet.

[0081] The coating layer disclosed in Table 1 below is formed on a vehicle surface 20 using a wet coating agent for a vehicle, wherein the wet coating agent for a vehicle contains 1 to 5 wt% of decamethylcyclopentasiloxane, 43 to 78 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, 40 to 50 wt% of amodimethicone oil, and 0.5 to 2 wt% of trifluoropropyltrimethoxysilane.

[0082] The vehicle surface 10 on which a wet coating agent for a vehicle has not been applied and thus a coating layer has not been formed is washed through the following steps: (1) pre-washing (high-pressure water washing), (2) applying snow foam or car shampoo to the vehicle surface, (3) rinsing with shampoo or snow foam, (4) pre-washing (high-pressure water washing), and (5) removing water from the vehicle. Then, the water contact angle of the vehicle surface 10 is measured using a contact angle meter.

[0083] Referring to FIG. 4, a first one-side angle 11 and a first other-side angle 12 are contact angles obtained by analyzing the contact angle of a water droplet applied to the vehicle surface 10, on which the coating layer has not been formed, using a contact angle meter.

[0084] The first one-side angle 11 means the angle formed between a first tangent line contacting with one side of a water droplet applied to the vehicle surface 10 on which a coating layer has not been formed and a portion of the vehicle surface 10 with which the water droplet contacts.

[0085] The first other-side angle 12 means the angle formed between a second tangent line contacting with the other side of a water droplet applied to the vehicle surface 10 on which a coating layer has not been formed and a portion of the vehicle surface 10 with which the water droplet contacts.

[0086] In this case, the first tangent line means, when viewed from the side of the water droplet, a line extending in a straight line for a predetermined distance from one end point of the contact surface where the water droplet and the vehicle surface 10 come into contact with each other toward a direction away from the vehicle surface 10 while contacting with a portion of the surface of the water droplet.

[0087] The first tangent line means, when viewed from the side of the water droplet, a line extending in a straight line for a predetermined distance from the other end point of the contact surface where the water droplet and the vehicle surface 10 come into contact with each other toward a direction away from the vehicle surface 10 while contacting with a portion of the surface of the water droplet.

[0088] Referring to Table 1 below, it can be confirmed that the values of the first one-side angle 11 and the first other-side angle 12 vary depending on the number of measurements, and in particular, it can be confirmed that the first one-side angle 11 and the first other-side angle 12 measured in the early stage are relatively higher than the first one-side angle 11 and the first other-side angle 12 measured in the later stage.

[0089] In addition, it can be confirmed that the values of the first one-side angle 11 and the first other-side angle 12 measured for a single identical water droplet by a contact angle meter exhibit a small deviation of 0.1 to 0.4° in all measurement runs.

[0090] The water contact angles (shown in Table 1) of a vehicle surface 20 on which the coating layer has been formed are values obtained by washing the vehicle surface, and then applying a water droplet to the vehicle surface 20 and measuring the contact angle of the water droplet using a KRUSS DSA25 contact angle meter.

[0091] As a result of measuring the contact angle of a water droplet applied to the vehicle surface 20 using a contact angle meter, it can be confirmed that hydrophilicity increases in proportion to a decrease in the contact angle of the water droplet, and hydrophobicity or water repellency increases in proportion to an increase in the contact angle of the water droplet.

[0092] Specifically, a second one-side angle 21 and a second other-side angle 22 refer to values obtained by repeating the operation of applying a water droplet to the vehicle surface 20 on which the coating layer has been formed and measuring the contact angle of the water droplet, a predetermined number of times.

[0093] The second one-side angle 21 means the angle formed between a third tangent line contacting with one side of a water droplet applied to the vehicle surface 20 on which the coating layer has been formed and a portion of the vehicle surface 20 with which the water droplet contacts.

[0094] The second other-side angle 22 means the angle formed between a fourth tangent line contacting with the other side of a water droplet applied to the vehicle surface 20 on which the coating layer has been formed and a portion of the vehicle surface 20 with which the water droplet contacts.

[0095] In this case, the third tangent line means, when viewed from the side of the water droplet, a line extending in a straight line for a predetermined distance from one end point of the contact surface where the water droplet and the vehicle surface 20 come into contact with each other toward a direction away from the vehicle surface 20 while contacting with a portion of the surface of the water droplet.

[0096] The fourth tangent line means, when viewed from the side of the water droplet, a line extending in a straight line for a predetermined distance from other end point of the contact surface where the water droplet and the vehicle surface 20 come into contact with each other toward a direction away from the vehicle surface 20 while contacting with a portion of the surface of the water droplet.

[0097] The vehicle surface 20 on which the coating layer has been formed is washed and coated through the following steps: (1) pre-washing (high-pressure water washing), (2) applying snow foam or car shampoo to the vehicle surface 20, (3) rinsing with shampoo or snow foam, (4) spraying the wet coating agent for a vehicle; (5) pre-washing (high-pressure water washing), and (6) removing water from the vehicle. Then, the water contact angle of the vehicle surface 20 is measured using a contact angle meter.

[0098] Referring to Table 1 below, it can be confirmed that the values of the second one-side angle 21 and the second other-side angle 22 vary depending on the number of measurements, and in particular, it can be confirmed that the second one-side angle 21 and the second other-side angle 22 measured in the early stage are relatively higher than the first one-side angle 11 and the first other-side angle 12 measured in the later stage.

[0099] In addition, it can be confirmed that the values of the second one-side angle 21 and the second other-side angle 22 measured for a single identical water droplet by a contact angle meter exhibit a small deviation of 0.1 to 0.8° in all measurement runs.

[0100] Water contact angle of vehicle surface 10 on which coating layer has not been formedWater contact angle of vehicle surface 10 on which coating layer has been formedRun No.First one-side angle 11First other-side angle 12Second one-side angle 21Second other-side angle 22193.7°93.6°104.2°104.2°282.5°82.7°103.7°103.0°371.4°71.0°103.3°103.2°482.3°82.1°111.0°111.1°582.9°83.1°109.3°110.1°Average value82.5106.3

[0101] In addition, referring to Table 1 above, it can be confirmed that the second one-side angle 21 and the second other-side angle 22 measured on the vehicle surface 20 on which the coating layer has been formed are respectively higher than the first one-side angle 11 and the first other-side angle 12 measured in all runs, suggesting that the hydrophobicity of the coating layer formed on the vehicle surface 20 is relatively higher than the hydrophobicity of the vehicle surface 10 on which the coating layer has not been formed.

[0102] In addition, it can be confirmed that, in the case of the vehicle surface 20 on which the coating layer has been formed, the second one-side angle 21 and the second other-side angle 22 measured in the later stages are relatively higher than the second one-side angle 21 and the second other-side angle 22 measured in the early stages, suggesting that the hydrophobicity or water repellency of the vehicle surface 20 is effectively maintained even when the vehicle surface 20 is repeatedly exposed to water droplets or water over a long period of time.

[0103] Friction coefficient of vehicle surface 10 on which coating layer has not been formedFriction coefficient of vehicle surface 20 on which coating layer has been formedRun No.Coefficient of static frictionCoefficient of dynamic frictionCoefficient of static frictionCoefficient of dynamic friction10.2840.3140.1000.09020.2760.3110.0940.08830.2580.2900.0950.08740.2660.2890.1020.08850.2690.3010.0920.090SD(standard deviation)0.0100.0120.0040.001CV (coefficient of variation)3.643.844.421.51Average0.2700.3010.0970.089

[0104] Referring to Table 2 above and FIGS. 5 and 6, the coefficients of friction disclosed in Table 2 are values obtained by measuring the coefficients of friction of the vehicle surface 10 on which the coating layer has not been formed and the vehicle surface 20 on the coating layer has been formed, using a friction coefficient measuring device (product name: WL2100 C, Withlab Co., Ltd.) according to the ASTM D 1894 standard.

[0105] The friction coefficient measuring device includes: a sliding member 52 that is in close contact with the vehicle surface 10 or 20; a weight 54 that is in close contact with or coupled to an upper surface of the sliding member 52; a wire 56 that has one end connected to the weight 54 and the other end connected to a load cell 58; and the load cell 58.

[0106] The coefficient of static friction means the coefficient of friction measured as the maximum value on the load cell 58 between the time when the sliding member 52 in contact with the vehicle surface 10 or 20 on which the coating layer has not been formed, the wire 56, and the load cell 58 begin to be pulled in a first direction and the time when the sliding member 52 starts to move in the first direction.

[0107] In other words, the coefficient of static friction means the maximum value of the frictional force until the moment when the sliding member 52, the wire 56, and the load cell 58 start to move in the first direction, and shows a high value when the slipperiness of the vehicle surface 10 or 20 is low.

[0108] The coefficient of dynamic friction represents the frictional force generated between the sliding member 52 and the vehicle surface 10 or 20 while the sliding member 52 in contact with the vehicle surface 10 or 20 on which the coating layer has not been formed moves in the first direction.

[0109] Referring to FIG. 6, the coefficient of static friction 63 represents the maximum static frictional force in a state where the static frictional force 62 increased to the maximum in the stationary state zone 64 of the sliding member 52 on a graph where the X-axis is the force 60 applied to the sliding member 52 and the Y-axis is the frictional force 61.

[0110] The coefficient of dynamic friction 65 refers to the frictional force generated between the vehicle surface 10 or 20 and the sliding member 52 during the movement state zone 66 of the sliding member 52 on a graph where the X-axis is the force 60 applied to the sliding member 52 and the Y-axis is the frictional force 61.

[0111] Referring to Table 2 above, it can be confirmed that each of the static friction coefficients 63 of the vehicle surface 10 on which the coating layer has not been formed shows a relatively lower value than the dynamic friction coefficient 65 measured immediately after the measurement of each static friction coefficient 63 in all measurement runs, suggesting that the slipperiness or slickness of the vehicle surface 10 is low.

[0112] In addition, it can be confirmed that each of the static friction coefficients 63 of the vehicle surface 10 shows a relatively higher value than each of the static friction coefficients 63 measured on the vehicle surface 20 on which the coating layer has been formed, suggesting that the slipperiness of the vehicle surface 10 is significantly lower than the slipperiness of the vehicle surface 20.

[0113] In addition, it can be confirmed that each of the static friction coefficients 63 of the vehicle surface 10 shows a relatively higher value than each of the static friction coefficients 63 measured on the vehicle surface 20 on which the coating layer has been formed, and that the adhesive force of the vehicle surface 10 is relatively higher than the adhesive force of the vehicle surface 20, suggesting that the probability of foreign substances adhering to the vehicle surface 20 is reduced, thereby improving the antifouling property of the vehicle surface 20.

[0114] In addition, it can be confirmed that each of the dynamic friction coefficients 65 of the vehicle surface 10 shows a relatively higher value than each of the dynamic friction coefficients 65 measured on the vehicle surface 20 on which the coating layer has been formed, indicating that the slipperiness of the vehicle surface 10 is significantly lower than the slipperiness of the vehicle surface 20.

[0115] In addition, it can be confirmed that each of the static friction coefficients 63 measured on the vehicle surface 20 on which the coating layer has been formed shows a relatively higher value than the dynamic friction coefficient 65 measured immediately after the measurement of each static friction coefficient 63 in all measurement runs, and that the sliding member 52 slides easily along the vehicle surface 20, indicating that the slipperiness and slickness of the vehicle surface 20 are excellent.

[0116] Meanwhile, the wet coating agent for a vehicle may further contain a UV blocking agent, wherein the UV blocking agent is composed of a core made of spherical silicone elastomer beads and a shell made of nano-sized titanium dioxide (TiO2) particles and an additive, wherein the additive may be at least one selected from the group consisting of a dispersant, a coupling agent, and an organic-inorganic composite sol (binder).

[0117] In this case, the dispersant and the binder are used to modify the surface of the silicone elastomer and as an adhesive to uniformly form a titanium dioxide coating layer on the surface of the silicone elastomer bead.

[0118] The binder is an aminoalkyl silane-based material. As a non-limiting example, the binder may be any one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-2-aminoethylaminopropyltriethoxysilane.

[0119] The dispersant is at least one selected from the group consisting of citric acid, malic acid, maleic acid, fumaric acid, succinic acid, acetic acid, formic acid, butanoic acid, hydrochloric acid, and nitric acid, and the binder is at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyl trimethoxysilane.

[0120] Specifically, in the process of preparing a titanium dioxide (TiO2) slurry that is used in the preparation of the UV blocking agent, 75.12 wt% (45.58 g) of lipophilically surface-treated titanium dioxide powder (MT-100SJ, particle size: about 20 nm) in ethanol in a reaction vessel, thereby preparing a slurry. The slurry is heat to 55℃, and 4.04 wt% (2.45 g) of citric acid as a dispersant is added thereto, followed by stirring for 2 hours. Next, 20.85 wt% (12.65 g) of an organic-inorganic composite sol as a binder is added thereto, followed by stirring for an additional 1 to 2 hours, thereby preparing a surface-treated titanium dioxide (TiO2) slurry.

[0121] Since the wet coating agent for a vehicle is converted into a coating layer on the vehicle's glass when used periodically and the coating layer may consist of multiple layers, and even a small amount of titanium dioxide powder provides a sufficient ultraviolet ray blocking effect, it is preferable that the amount of titanium dioxide powder contained in the titanium dioxide slurry is 75.12 wt% (45.58 g) or less.

[0122] In a first process of preparing the organic-inorganic composite sol, 9 wt% (30 g) of boehmite powder is added to 90.01 wt% (300 g) of purified water, followed by stirring, thereby preparing a slurry for a composite sol. Then, 0.99 wt% (3.3 g) of acetic acid is added to the slurry, followed by stirring at room temperature for 1 hour.

[0123] In a second process of preparing the organic-inorganic composite sol, the stirred slurry for a composite sol is heated to 70℃, allowed to react for 2 hours, and cooled to room temperature, and then purified water is added thereto so that the total weight becomes 300 g, thereby synthesizing an alumina sol.

[0124] In a third process of preparing the organic-inorganic composite sol, 8.1 wt% (39 g) of 3-glycidoxypropyltrimethoxysilane (GPS) is added to 20.07 wt% (130 g) and stirred at room temperature for 1 hour. Then, 64.88 wt% (312.2 g) of the alumina sol is added thereto while heating to 70℃, and heated for 4 hours, thereby preparing the organic-inorganic composite sol.

[0125] The organic-inorganic composite sol forms a transparent film when dried at 100℃, and the formed film is insoluble in water and ethanol, so it may be used as a binder.

[0126] Meanwhile, in a separate reaction vessel, 13.86 wt% (32.19 g) of silicone elastomer beads (SB 902) are added to 86.14 wt% (200 g) of purified water and stirred for a predetermined period of time, thereby preparing an aqueous dispersion.

[0127] In another reaction vessel, 14.37 wt% (50 g) of ethanol and 1.44 wt% (5 g) of purified water are added, and heated to about 55℃ with stirring, and the titanium dioxide (TiO2) slurry and the aqueous dispersion are slowly and simultaneously added thereto, causing coprecipitation. After coprecipitation is complete, the resulting material is heated for an additional hour and cooled to room temperature, and when a precipitate layer is formed at the bottom, the clear water at the top is discharged to the outside.

[0128] After filtering the liquid contained in the precipitate using filter paper, the residue is dried at 60℃, pulverized by dry ball milling, and passed through a 200 mesh sieve, thereby preparing a UV blocking agent in the form of a composite powder.

[0129] The additive is at least one selected from the group consisting of a dispersant, a binder, and an organic-inorganic composite sol, and is preferably added in the step of preparing the titanium dioxide slurry, the step of preparing the aqueous dispersion, and the step of preparing the UV blocking agent in the form of a composite powder.

[0130] The wet coating agent for a vehicle containing the prepared UV blocking agent is less likely to penetrate the skin even if it accidentally comes into contact with the skin, and exhibits high SPF and PA values, thereby exhibiting an excellent UV blocking effect.

[0131] In addition, the silicone elastomer used as the core component of the UV blocking agent feels soft, and thus has the advantage of preventing scratches or damage to the vehicle surface during the process of spraying the wet coating agent for a vehicle onto the vehicle surface.

[0132] The wet coating for a vehicle may further contain a light-reflective composition, wherein the light-reflective composition is a coating composition including organosilane-functionalized colloidal silica and hollow microspheres, wherein the organosilane-functionalized colloidal silica includes silica particles having one or more organosilane moieties bonded to the surface of the silica particles, and the hollow microspheres include a polymeric shell.

[0133] Specifically, the organosilane-functionalized colloidal silica may be prepared by the method described in WO 2004 / 035473, and is formed from the reaction between one or more organosilane reactants, which can generally be represented by the formula T4-ySi-[R1]y, and one or more silanol groups, i.e., [SiO2]-OH groups, on the silica surface. Also, one or more organosilane moieties are attached to the silica surface.

[0134] In the formula of the organosilane reactant, each T is typically independently selected from C1-6 alkoxy, C1-6 haloalkoxy, hydroxy, and halide. Other options are the use of a siloxane, for example, a siloxane of the formula [R1]bT3-bSi{-O-SiT2-c[R1]c}a-O-SiT3-b[R1]b, wherein a is 0 or an integer greater than or equal to 1, typically from 0 to 5, b is from 1 to 3, and c is from 1 to 2.

[0135] Other examples include disilazanes of the formula {[R1]bT3-bSi}2-NH, wherein b is 1 to 3. Of the haloalkoxy groups, fluoro and chloro are preferred halo substituents.

[0136] Alkoxy groups and halides are often preferred as the T species. Of the halides, chloride is a suitable choice, and of the alkoxy groups, C1-4 alkoxy groups such as methoxy, ethoxy, propoxy or isopropoxy are suitable choices.

[0137] The organosilane reactant can undergo a prehydrolysis step, in which one or more T groups are converted to -OH, as described by Greenwood and Gevert, Pigment and Resin Technology, 2011, 40(5), pp 275-284.

[0138] The organosilanes includes epoxy groups, such as epoxyalkyl silane or epoxyalkyloxyalkyl silane, wherein the epoxy groups can be hydrolyzed to form corresponding vicinal diol groups.

[0139] There can be more than one different organosilane in the functionalized colloidal silica, and the organosilane-functionalized silica is produced by reacting a mixture of two or more organosilanes with colloidal silica, or by mixing two or more separately prepared organosilane-functionalized colloidal silicas.

[0140] Organosilane-functionalized colloidal silica particles exhibit stability without substantially gelling or precipitating for at least 2 to 4 months at normal storage at room temperature.

[0141] The coating layer containing organosilane-functionalized colloidal silica have improved tear resistance, tensile strength, reflectance of electromagnetic radiation over the wavelength range of 280 to 2,500 nm, dirt pick-up resistance (antifouling property) to both hydrophobic and hydrophilic materials, and storage stability, compared to a coating layer not containing organosilane-functionalized colloidal silica.

[0142] The microspheres included in the light reflective composition are hollow and improve the visible light and near-infrared reflectance of the light reflective composition. As the microspheres, hollow expanded expandable microspheres are preferably used.

[0143] Expandable microspheres comprise a thermoplastic polymer shell, enclosing one or more volatile fluids. When heated, the volatile fluid expands, causing corresponding expansion of the microspheres to produce the expanded microspheres.

[0144] The average diameter of the expandable microspheres contained in the light-reflective composition is 300 to 500 μm, and non-expandable microspheres can also be contained in the light-reflective composition. Examples of suitable microspheres are those described in WO2007 / 073318, and also those sold under the trade name ExpancelTM.

[0145] The microspheres contained in the light reflective composition have the advantage of improving the storage stability, durability, reflectance over the wavelength range of 280 to 2,500 nm, and wet adherence of a coating layer containing the light reflective composition.

[0146] Therefore, the light reflective composition has improved wet adherence by the microspheres contained therein, and thus has the advantage of forming a stable coating the vehicle surface when sprayed on the vehicle surface together with the wet coating agent for a vehicle.

[0147] When the vehicle surface is coated with the wet coating agent for a vehicle containing a light reflective composition comprising microspheres and organosilane-functionalized colloidal silica, the long-term durability, tensile strength, light reflectance, wet adherence, and antifouling properties thereof are improved.

[0148] The light reflective composition may further contain an organic binder, wherein the organic binder is at least one organic binder selected from the group consisting of water-soluble resins and water-soluble polymers.

[0149] Water-soluble resins and polymers include poly(vinyl alcohol), modified poly(vinyl alcohol), polycarboxylates, poly(ethylene glycol), poly(propylene glycol), polyvinylpyrrolidone, polyallylamine, polyacrylic acid, polyamideamine, polyacrylamide, and polypyrrole.

[0150] When the wet coating agent for a vehicle containing the light-reflective composition is sprayed onto the vehicle surface to form a coating layer and the coating layer is applied to the glass surface of the vehicle, it has the advantage of reflecting light over the wavelength range of 280 to 2,500 nm.

[0151] <Example 1>

[0152] A first mixture is prepared by stirring 1 to 5 wt% of decamethylcyclopentasiloxane, 42 to 55 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, and 40 to 50 wt% of amodimethicone oil at 50 to 100 rpm for 9.5 to 18.5 hours.

[0153] Next, 0.5 to 2 wt% of trifluoropropyltrimethoxysilane, one of the fluorinated alkoxysilanes, is added to the first mixture, followed by stirring at 50 to 100 rpm for 5 to 10 hours, thereby preparing a second mixture.

[0154] Next, 1 to 23 wt% of purified water is additionally added to the second mixture, followed by stirring at 50 to 100 rpm for 3 to 8 hours, thereby preparing a third mixture. The third mixture is packaged or injected into a container, thereby preparing a wet coating agent for a vehicle.

[0155] <Example 2>

[0156] A first mixture solution is prepared by stirring 1 to 5 wt% of decamethylcyclopentasiloxane, 42 to 55 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, and 40 to 50 wt% of amodimethicone oil at 50 to 100 rpm for 7.5 to 16.5 hours.

[0157] Next, 0.5 to 2 wt% of triethoxyoctylsilane, one of the fluorinated silanes, is added to the first mixture, followed by stirring at 50 to 100 rpm for 3 to 7 hours, thereby preparing a second mixture.

[0158] Next, 1 to 23 wt% of purified water is additionally added to the second mixture, followed by stirring at 50 to 100 rpm for 3 to 6 hours, thereby preparing a third mixture. The third mixture is packaged or injected into a container, thereby preparing a wet coating agent for a vehicle.

[0159] Triethoxyoctylsilane contained in the wet coating agent for a vehicle has the advantage of forming a hydrophobic layer on the vehicle surface when the wet coating agent forms a coating layer on the vehicle surface, thereby improving the hydrophobicity, water repellency, oxidation resistance, base resistance, and corrosion resistance of the coating layer.

[0160] In addition, triethoxyoctylsilane contained in the wet coating agent for a vehicle has the advantage of improving the mixing and dispersion of the first mixture in the wet coating agent formed of a polymer, thereby reducing the preparation time of the wet coating agent for a vehicle of Example 1.

[0161] <Example 3>

[0162] A first mixture is prepared by stirring 1 to 5 wt% of decamethylcyclopentasiloxane, 42 to 55 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, and 40 to 50 wt% of amodimethicone oil at 50 to 100 rpm for 9.5 to 18.5 hours.

[0163] Next, 0.5 to 1 wt% of trichlorosilane, one of the fluorinated alkoxysilanes, is added to the first mixture, followed by stirring at 50 to 100 rpm for 5 to 10 hours, thereby preparing a second mixture.

[0164] Next, 1 to 23 wt% of purified water is additionally added to the second mixture, followed by stirring at 50 to 100 rpm for 3 to 8 hours, thereby preparing a third mixture. The third mixture was packaged or injected into a container, thereby preparing a wet coating agent for a vehicle.

[0165] Trichlorosilane contained in the wet coating agent for a vehicle is a crosslinkable silane compound, and when mixed with decamethylcyclopentasiloxane containing silica particles, it has the advantage of blocking the agglomeration of decamethylcyclopentasiloxane, thereby improving the mixing and dispersion of the second mixture.

[0166] Thereby, when the wet coating agent for a vehicle containing trichlorosilane is converted into a coating layer on the vehicle surface, the thickness of the coating layer becomes uniform, and the wet coating agent for a vehicle of Example 3 has an advantage over the wet coating agents of Examples 1 and 2 in that it can form a coating layer on the same area of the vehicle surface even when it is used in relatively small amounts.

[0167] <Example 4>

[0168] Before performing the first stirring step (S110), there is performed a nitrogen introduction step in which nitrogen gas is introduced into a reaction vessel to fill the inside of the reaction vessel with nitrogen and, when the inside of the reaction vessel is filled with nitrogen, introduction of nitrogen gas is stopped.

[0169] A first mixture is prepared by stirring 1 to 5 wt% of decamethylcyclopentasiloxane, 2 to 5 wt% of the UV blocking agent, 40 to 50 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, and 40 to 50 wt% of amodimethicone oil at 50 to 100 rpm for 4.5 to 13.5 hours.

[0170] Next, 0.5 to 2 wt% of trifluoropropyltrimethoxysilane, one of the fluorinated alkoxysilanes, is added to the first mixture, followed by stirring at 50 to 100 rpm for 2 to 6 hours, thereby preparing a second mixture.

[0171] Next, 1 to 23 wt% of purified water is additionally added to the second mixture, followed by stirring at 50 to 100 rpm for 1 to 4 hours, thereby preparing a third mixture. The third mixture is packaged or injected into a container, thereby preparing a wet coating agent for a vehicle.

[0172] The UV blocking agent contained in the wet coating agent for a vehicle has the advantage of blocking ultraviolet rays from entering the interior of the vehicle through the glass when the wet coating agent for a vehicle forms a coating layer on the glass surface of the vehicle.

[0173] In addition, in Example 4, there is an advantage in that since the wet coating agent for a vehicle is prepared in the reaction vessel filled with nitrogen, the mixing and reaction of decamethylcyclopentasiloxane, the UV blocking agent, purified water, the alcohol-based nonionic surfactant, amodimethicone oil, and trifluoropropyltrimethoxysilane in the first stirring step (S110), the second stirring step (S120), and the third stirring step (S130) are stably performed.

[0174] In addition, in Example 4, there is an advantage in that since the wet coating agent for a vehicle is stably prepared in the reaction vessel filled with nitrogen, the preparation time of the wet coating agent for a vehicle is relatively shorter than the preparation time in each of Examples 1 to 3.

[0175] Meanwhile, the UV blocking agent is composed of a core made of spherical silicone elastomer beads and a shell made of nano-sized titanium dioxide particles and an additive, wherein the additive may be at least one selected from the group consisting of a dispersant, a binder, and an organic-inorganic composite sol. A specific method for preparing the UV blocking agent has been mentioned above, and thus the description thereof is omitted to avoid redundancy.

[0176] In addition, in Example 4, triethoxyoctylsilane may be used instead of trifluoropropyltrimethoxysilane. In this case, the first mixture may be prepared by stirring at 50 to 100 rpm for 4 to 13 hours in the first stirring step, the second mixture may be prepared by stirring at 50 to 100 rpm for 1 to 5 hours in the second stirring step, and the third mixture may be prepared by stirring at 50 to 100 rpm for 1 to 3 hours in the third stirring step.

[0177] <Example 5>

[0178] Before performing the first stirring step (S110), there is performed a nitrogen introduction step in which nitrogen gas is introduced into a reaction vessel to fill the inside of the reaction vessel with nitrogen and, when the inside of the reaction vessel is filled with nitrogen, introduction of nitrogen gas is stopped.

[0179] A first mixture is prepared by stirring 1 to 5 wt% of decamethylcyclopentasiloxane, 2 to 5 wt% of the UV blocking agent, 35 to 48 wt% of purified water, 5 to 10 wt% of an alcohol-based nonionic surfactant, and 40 to 50 wt% of amodimethicone oil at 50 to 100 rpm for 4.5 to 13.5 hours.

[0180] Next, 0.5 to 2 wt% of trifluoropropyltrimethoxysilane, one of the fluorinated alkoxysilanes, is added to the first mixture, followed by stirring at 50 to 100 rpm for 2 to 6 hours, thereby preparing a second mixture.

[0181] Next, 1 to 23 wt% of purified water is additionally added to the second mixture, followed by stirring at 50 to 100 rpm for 1 to 4 hours, thereby preparing a third mixture.

[0182] Next, 3.5 to 5.5 wt% of a light-reflective composition is added to the third mixture, followed by stirring, thereby preparing a fourth mixture. The fourth mixture is packaged or injected into a container, thereby preparing a wet coating agent for a vehicle.

[0183] The UV blocking agent contained in the above wet coating agent for a vehicle has the advantage of blocking ultraviolet rays from passing through the glass and entering the interior of the vehicle, when the wet coating agent for a vehicle forms a coating layer on the glass surface of the vehicle.

[0184] In addition, in Example 5, there is an advantage in that since the wet coating agent for a vehicle is prepared in the reaction vessel filled with nitrogen, the mixing and reaction of decamethylcyclopentasiloxane, the UV blocking agent, purified water, the alcohol-based nonionic surfactant, amodimethicone oil, and trifluoropropyltrimethoxysilane in the first stirring step (S110), the second stirring step (S120), and the third stirring step (S130) are stably performed.

[0185] In addition, in Example 5, there is an advantage in that since the wet coating agent for a vehicle is stably prepared in a reaction tank filled with nitrogen, the preparation time of the wet coating agent for a vehicle is relatively shorter than the preparation time in each of Examples 1 to 3.

[0186] Meanwhile, the UV blocking agent is composed of a core made of spherical silicone elastomer beads and a shell made of nano-sized titanium dioxide particles and an additive, wherein the additive may be at least one selected from the group consisting of a dispersant, a binder, and an organic-inorganic composite sol. A specific method for preparing the UV blocking agent is mentioned above, and thus is omitted to avoid redundant description.

[0187] The light-reflective composition is a coating composition comprising organosilane-functionalized colloidal silica and hollow microspheres, wherein the organosilane-functionalized colloidal silica comprises silica particles having at least one organosilane moiety bonded to the surface of the silica particles, and the hollow microspheres comprise a polymeric shell. A specific method for preparing the light-reflective composition has been mentioned above, and thus the description thereof is omitted to avoid redundancy.

[0188] In Example 5, there is an advantage in that since the wet coating agent for a vehicle is prepared in the reaction vessel filled with nitrogen, the overall preparation time and production cost are reduced and the defect rate is reduced.

[0189] In addition, there is an advantage in that since the coating layer formed by spraying the wet coating agent for a vehicle onto the glass surface of the vehicle contains the UV blocking agent, it effectively blocks ultraviolet rays harmful to the human body, thereby protecting the bodies of users seated inside the vehicle.

[0190] In addition, there is an advantage in that since the coating layer formed by spraying the wet coating agent for a vehicle onto the glass surface of the vehicle contains the light-reflective composition, it effectively blocks light from entering the vehicle surface, the glass surface of the vehicle, or the interior of the vehicle, thus significantly reducing the phenomenon of heat generation caused by increased temperature on the vehicle surface and in the interior of vehicle compared to the coating layer formed by the wet coating agent for a vehicle prepared in each of Examples 1 to 4 in the same environment.

[0191] Although preferred embodiments of the present disclosure have been described with reference to the accompanying drawings, the embodiments described in the present specification and the configurations illustrated in the drawings are merely examples and do not exhaustively present the technical spirit of the present disclosure. Accordingly, it should be appreciated that there may be various equivalents and modifications that can replace the embodiments and the configurations at the time of filing of the present application. Therefore, the embodiments described above are considered to be illustrative in all respects and not restrictive. Furthermore, the scope of the present disclosure is defined by the appended claims rather than the detailed description, and it should be understood that all modifications or variations derived from the meanings and scope of the present disclosure and equivalents thereto are included in the scope of the present disclosure.

Claims

1.A wet coating agent for a vehicle containing decamethylcyclopentasiloxane, purified water, an alcohol-based nonionic surfactant, amodimethicone oil, and a fluorinated silane.2.The wet coating agent of claim 1, containing 1 to 5 wt% of the decamethylcyclopentasiloxane, 43 to 78 wt% of the purified water, 5 to 10 wt% of the alcohol-based nonionic surfactant, 40 to 50 wt% of the amodimethicone oil, and 0.5 to 2 wt% of the fluorinated silane.3.A method for preparing a wet coating agent for a vehicle, the method comprising:a first stirring step of stirring decamethylcyclopentasiloxane, purified water, an alcohol-based nonionic surfactant, and amodimethicone oil, thereby preparing a first mixture;a second stirring step of adding a fluorinated silane to the first mixture, thereby preparing a second mixture; anda third stirring step of adding purified water to the second mixture, thereby preparing a third mixture.4.The method of claim 3, wherein the first stirring step comprises stirring 1 to 5 wt% of the decamethylcyclopentasiloxane, 42 to 55 wt% of the purified water, 5 to 10 wt% of the alcohol-based nonionic surfactant, and 40 to 50 wt% of the amodimethicone oil.5.The method of claim 4, wherein the second stirring step comprises adding 0.5 to 2 wt% of the fluorinated silane, followed by stirring.6.The method of claim 5, wherein the third stirring step comprises additionally adding 1 to 23 wt% of the purified water, followed by stirring.7.The method of claim 6, wherein the fluorinated silane is trifluoropropyltrimethoxysilane.

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