Antifouling and cleaning hydrophilic coating composition and hydrophilic processing method using the same

Abstract

To provide a hydrophilic coating agent composition which has a glossy feeling, a uniform and clean appearance, and a hydrophilic property and excels in sustainability of hydrophilicity even if the number of times of water rinse is large, and to provide a hydrophilic processing method using the composition.SOLUTION: There is provided a hydrophilic coating agent composition including: polyvinyl alcohol as a component (A); a fluorine-based surfactant and / or a silicone-based surfactant as a component (B); and water as a component (C).SELECTED DRAWING: None

Description

Detailed Description of the Invention [Technical Field]

[0001] The present invention relates to a hydrophilic coating composition for hard surfaces such as ceramics, tiles, glass, enamel, and metals. [Background technology]

[0002] Various types of dirt adhere to the hard surfaces of toilet bowls and washbasins depending on where they are used. For example, dirt on toilet bowls is caused by excrement such as human waste and urinary stones, while dirt on washbasins is caused by soap scum from hand soap, toothpaste, cosmetics, phlegm, etc. Furthermore, because these hard surfaces are constantly in contact with tap water and repeatedly dried, silicate scale and carbonate scale derived from tap water are locally concentrated and adhere to the surfaces, resulting in the adhesion of dirt commonly known as water spots or limescale. In toilets used by many people, such as those in train stations, highway service areas, buildings, and restaurants, cleaning the toilets several times a day is essential. Neglecting cleaning can lead to the accumulation of excrement, limescale, and other contaminants, which dry and bond firmly to the hard surface, making them difficult to remove. It can also become a breeding ground for mold and bacteria, creating hygiene problems. However, when multiple toilets are installed in a single facility, the workload of cleaning the toilets is significant, and labor shortages make it difficult to share the work. Therefore, there is a need to reduce the frequency of toilet cleaning and other work.

[0003] To solve this problem, a method has been proposed in which a film is formed on the target hard surface, and the film surface gradually dissolves when in contact with water, thereby washing away the dirt adhering to the surface. Patent Document 1 discloses a spray agent obtained by filling a coating composition containing a water-soluble polymer, a metal salt that forms a poorly water-soluble metal hydroxide, and water into a container equipped with a spraying device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-50586 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology of Patent Document 1, a slowly dissolving film that is resistant to water flow is formed on the hard surface, so there is no risk of the entire film disappearing all at once, but the film that peels off along with the dirt is not thick enough, resulting in insufficient stain resistance. Furthermore, if the film attached to the hard surface is uneven or hydrophobic or water-resistant, urine and rinsing water that adhere to the film will be repelled, resulting in partial accumulation of dirt as the dirt repeatedly flows off with the film, and there is also the problem that it is difficult to maintain the coated surface in a visually clean state due to partial peeling and whitening of the film. [Means for solving the problem]

[0006] As a result of extensive research by the inventors to solve the above problems, the inventors have completed the following invention. The first aspect of the present invention is a hydrophilic coating agent composition comprising polyvinyl alcohol as component (A), a fluorine-based surfactant and / or a silicone-based surfactant as component (B), and water as component (C).

[0007] The second gist of the present invention is a hydrophilic coating composition characterized by containing, as component (D), a nonionic surfactant having a melting point of 40 to 70°C.

[0008] The third aspect of the present invention is a hydrophilic treatment method including a pre-step of cleaning the surface to be coated before applying the hydrophilic coating composition to the hard surface.

[0009] The fourth gist of the present invention is a hydrophilic processing method including, in the pre-processing step, a step of cleaning the surface to be coated with an acidic cleaning agent.

[0010] The fifth aspect of the present invention is a hydrophilic processing method including a step of polishing the surface to be coated in the pre-processing step. [Effects of the Invention]

[0011] According to the present invention, a coating having a sufficient thickness that combines a glossy, uniform, and clean appearance with hydrophilicity can be formed on the surface to be coated. That is, a coating having a sufficient thickness remains on the coated hard surface even after multiple rinses, so that not only does the antifouling effect last for a long time, but the hydrophilicity of the hard surface also lasts for a long time, making it possible to reduce the frequency of toilet cleaning during facility maintenance while maintaining the aesthetic appearance of the toilet. Furthermore, because a smooth coating is formed when the hydrophilic coating composition is applied, rinse water and urine spread over the surface, resulting in less uneven peeling of the coating and no water droplets remaining until the next application of the hydrophilic coating composition, the coated surface also exhibits the effect of maintaining a visually glossy, uniform, and clean state. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, the best mode for carrying out the present invention will be described in detail.

[0013] First, polyvinyl alcohol is used as component (A) in the present invention. The use of polyvinyl alcohol allows for the formation of a hydrophilic, glossy coating. Usable polyvinyl alcohols include those with an average degree of polymerization of 200 to 5000 and a degree of saponification of 70 to 100 mol%. From the standpoints of water solubility in the hydrophilic coating composition and the viscosity of the undiluted composition, those with an average degree of polymerization of 1000 to 5000 and a degree of saponification of 85 to 100 mol% are preferred. Considering the antifouling properties and sustained hydrophilicity of the hydrophilic coating composition, those with an average degree of polymerization of 2000 to 5000 and a degree of saponification of 98 to 100 mol% are even more preferred. The average degree of polymerization and degree of saponification referred to here can be determined in accordance with JIS K 6726 (Testing Methods for Polyvinyl Alcohol). These may be used alone, or two or more different average degrees of polymerization or degrees of saponification may be used in combination.

[0014] The above-mentioned component (A) is contained in a proportion of 0.5 to 25% by mass based on the total hydrophilic coating composition of the present invention. That is, if the amount is too small, it will be disadvantageous in terms of the durability of the antifouling effect and hydrophilic effect, and if the amount is too large, the viscosity of the hydrophilic coating composition will be too high, which may make it difficult to apply uniformly. Furthermore, the composition may solidify or gel, reducing its storage stability. Therefore, the preferred range is 1 to 20% by mass, and more preferably 2 to 15% by mass.

[0015] The component (B) used in the present invention is a fluorine-based surfactant and / or a silicone-based surfactant. The use of a fluorine-based surfactant and / or a silicone-based surfactant exhibits leveling properties, allowing the formation of a uniform film on the surface. Furthermore, the formed film dissolves when it comes into contact with urine or rinse water, but at the same time, the surfactant contained therein is eluted, which has a leveling effect that uniformly diffuses the urine or rinse water, preventing urine stains and water stains.

[0016] Usable fluorosurfactants include perfluorosulfonic acid (PFOS) surfactants synthesized by electrolytic fluorination, perfluorocarboxylic acid (PFOA) surfactants synthesized by telomerization, and fluorinated ethylene polymer surfactants synthesized by oligomerization. From the viewpoint of forming a uniform film, fluorosurfactants with alkyl groups having 6 to 12 carbon atoms are preferred. These surfactants may be used alone or in combination of two or more.

[0017] Usable silicone surfactants include those in which hydrophilic substituents have been introduced into a portion of dimethylpolysiloxane. The hydrophilic substituents can be introduced at the side chain of the dimethylpolysiloxane, both ends, one end, or multiple locations, such as the side chain and both ends. The hydrophilic substituents can be polyether-modified, such as polyoxyethylene or a block polymer of polyoxyethylene and polyoxypropylene, or amino-modified, such as alkylamines. Examples include amino-polyether-modified, which incorporates both of the above. Other examples include amide-polyether-modified, in which alkylamides are substituted with polyoxyethylene or polyoxypropylene, and in which the hydrophilic substituents are combined with all three of the above. The hydrophobic dimethylpolysiloxane can be linear or branched, or linear with alkyl groups attached. These can be used alone or in combination. Among these, the type in which polyoxyethylene and polyoxypropylene are bonded to heptamethyltrisiloxane is preferred in terms of forming a uniform film.

[0018] The (B) component is contained in an amount of 0.01 to 2.0% by mass relative to the total amount of the hydrophilic coating composition of the present invention. If the amount is too small, the uniformity of the finished coating film will be insufficient. If the amount is too large, the effect of improving the finished coating film will be saturated and it will be economically disadvantageous. Therefore, the preferred range is 0.02 to 1.5% by mass, and more preferably 0.03 to 1.0% by mass.

[0019] Examples of water, which is component (C) used in the present invention, include pure water, ion-exchanged water, soft water, distilled water, and tap water. These may be used alone or in combination of two or more. Among these, tap water and ion-exchanged water are preferred from the standpoints of economy and storage stability. The above "water" refers to the sum of water contained in the form of water of crystallization or aqueous solution derived from each component constituting the antifouling detergent composition of the present invention, and water added from the outside, and is blended so that the total amount of the hydrophilic coating agent composition is 100%.

[0020] In addition to the essential components (A) to (C), the present invention can also include a nonionic surfactant (D) with a melting point of 40 to 70°C. This further improves the durability of the hydrophilicity of the coating film. The melting point can be determined in accordance with JIS K 0064 (Method for measuring the melting point and melting range of chemical products). Considering the durability of hydrophilicity, the glossiness of the film, and the storage stability of the hydrophilic coating composition, it is preferable to incorporate a nonionic surfactant with a melting point of 40 to 70°C. That is, if a nonionic surfactant with a melting point that is too low is incorporated, the solubility increases, making the film more likely to come off during rinsing, which is disadvantageous in terms of the durability of hydrophilicity. On the other hand, if a nonionic surfactant with a melting point that is too high is incorporated, a film that lacks glossiness is formed, and poor solubility in the hydrophilic coating composition makes it disadvantageous in terms of storage stability.

[0021] Examples of the nonionic surfactant having a melting point of 40 to 70°C, which is component (D) used in the present invention, include alkylene oxide adducts of higher alcohols or alkylamines (e.g., polyoxyethylene alkyl ethers, polyoxyethylene alkylamines, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene polyoxypropylene alkylamines, etc.), Pluronic block polymers, reverse Pluronic block polymers, ethylene oxide propylene oxide adducts of polyhydric alcohols, ethylene oxide propylene oxide adducts of glycerin, polyglyceryl alkyl ethers, glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene glycerin stearate, alkyl polyglucosides, fatty acid alkanolamides, etc. These may be used alone or in combination of two or more. Among these, polyoxyethylene alkyl ethers, pluronic block polymers, glycerin fatty acid esters, sorbitan fatty acid esters, and polyoxyethylene glycerin stearate, each having a melting point of 40 to 70°C, are preferred in terms of the durability of the hydrophilicity of the coating film.

[0022] Examples of the polyoxyethylene alkyl ether include polyoxyethylene alkyl ethers in which an average of 20 to 100 moles of ethylene oxide (EO) are added to an alcohol having a linear or branched hydrocarbon group with 6 to 24 carbon atoms, and among these, polyoxyethylene alkyl ethers in which an average of 30 to 80 moles of ethylene oxide are added to an alcohol having a linear or branched hydrocarbon group with 9 to 18 carbon atoms are preferably used.

[0023] The Pluronic block polymer preferably has an average molecular weight in the range of 4,000 to 30,000, an average number of moles of ethylene oxide added of 100 to 500 moles, and an average number of moles of propylene oxide added of 20 to 100 moles. Of these, the Pluronic block polymer preferably has an average molecular weight in the range of 6,000 to 20,000, an average number of moles of ethylene oxide added of 120 to 400 moles, and an average number of moles of propylene oxide added of 25 to 60 moles.

[0024] The glycerin fatty acid esters include monoesters, diesters, and triesters having an alkyl group with 9 to 24 carbon atoms and an average glycerin condensation degree of 1 to 10, and among these, monoesters or diesters having an alkyl group with 11 to 18 carbon atoms and an average condensation degree of 1 to 5 are preferred.

[0025] The sorbitan fatty acid esters include monoesters, diesters and triesters in which the alkyl group has 9 to 24 carbon atoms, and among these, monoesters and diesters in which the alkyl group has 11 to 18 carbon atoms are preferred.

[0026] The polyoxyethylene glycerin stearate may be a monoester, diester, or triester having an alkyl group carbon number of 9 to 24, an average number of added moles of polyoxyethylene of 1 to 10 moles, and an average degree of condensation of glycerin of 1 to 10. Of these, a monoester or diester having an alkyl group carbon number of 11 to 18, an average number of added moles of polyoxyethylene of 1 to 5 moles, and an average degree of condensation of glycerin of 1 to 5 is preferred.

[0027] The (D) component is contained in an amount of 0.1 to 5% by mass relative to the total amount of the hydrophilic coating composition of the present invention. In consideration of improving the durability of the hydrophilicity of the coating film and the storage stability of the composition, the amount is preferably in the range of 0.3 to 4% by mass, and more preferably 0.5 to 3.5% by mass.

[0028] In consideration of not adversely affecting the material of the target surface and of safety to the human body and the environment, the pH of the hydrophilic coating composition of the present invention is preferably 5 to 9. Furthermore, in consideration of the finish of the coating film and the viscosity stability of the hydrophilic coating composition, it is more preferable that the pH be adjusted to the range of 6 to 8.

[0029] The pH is adjusted using alkaline and acidic substances.

[0030] Alkaline substances used to adjust the pH include alkali hydroxides such as sodium hydroxide and potassium hydroxide, carbonates such as sodium carbonate and potassium carbonate, silicates such as sodium silicate and potassium silicate, amines such as monoethanolamine and diethanolamine, and ammonia. Acidic substances used to adjust the pH include inorganic acids such as hydrochloric acid and sulfuric acid, and organic acids such as citric acid, acetic acid, and lactic acid.

[0031] The hydrophilic coating agent composition of the present invention may contain, as optional components, enzyme activity inhibitors, solvents, dyes, fragrances, metal corrosion inhibitors, bactericides, antibacterial agents, deodorizers, antistatic agents, antioxidants, thickeners, fluorescent brighteners, etc., within the scope of not impairing the object of the present invention.

[0032] The hydrophilic coating composition of the present invention preferably has a viscosity at 20°C measured with a Brookfield viscometer of 10 to 3000 mPa·s, more preferably 30 to 1000 mPa·s, and even more preferably 50 to 500 mPa·s, from the viewpoint of the durability of the hydrophilicity of the coating film.

[0033] The hydrophilic coating composition of the present invention forms a coating film on the surface to be coated, and repeatedly exhibits a mechanism of washing away dirt adhering to the film surface together with the film by rinsing with water, and is therefore particularly suitable for use in antifouling hard surfaces such as toilets, washstands, bathrooms, etc. Materials for these hard surfaces include ceramics, tile, glass, enamel, metal, and natural stone materials such as granite and marble.

[0034] Before applying the hydrophilic coating composition of the present invention to a target surface, it is preferable to carry out a pre-process of cleaning the target surface. When the target surface is covered with limescale, urinary stones, or other dirt, carrying out a pre-process of cleaning the target surface prevents the hydrophilic coating composition from being repelled and allows a good film to be formed. The method of cleaning in the pre-process is not particularly limited, but examples thereof include: (1) Soak a sponge or scrubbing pad in the cleaning agent, scrub the surface to be treated, and then rinse with water. (2) Sprinkle the cleaning agent directly onto the surface to be treated, scrub with a sponge, etc., and then rinse with water. (3) Spray the cleaning agent on the surface to be treated, leave it for a while, then scrub and rinse with water, or rinse with water without scrubbing. (4) For vertical or curved surfaces, the cleaning agent is soaked in nonwoven fabric, etc., and applied to the surface. After leaving it for a while, the cleaning agent is rinsed with water. (5) A method in which a towel or duster is soaked in the cleaning agent, dirt is wiped off from the surface to be treated, and then the surface is wiped off with a towel soaked in water. etc.

[0035] The cleaning agent for the pre-treatment step can be selected depending on the dirt adhering to the surface to be coated. For example, in toilets and washbasins, it is preferable to use an acidic cleaning agent. This allows stubborn limescale, urinary stones, and soap scum to be efficiently removed. Removing the dirt in advance improves the aesthetic appearance of the surface to be coated and also enables the film of the hydrophilic coating composition to be applied more uniformly.

[0036] Furthermore, it is preferable that the preceding process includes a polishing process using an abrasive that does not damage the glaze on the surface of the toilet bowl or washbasin. The polishing method is not particularly limited, but examples thereof include: (1) A method in which a sponge or nonwoven fabric is soaked in an abrasive cleaning agent, the surface to be treated is scrubbed, and then the surface is rinsed with water. (2) Sprinkle the abrasive cleaner directly onto the surface to be treated, scrub with a sponge, etc., and then rinse with water. (3) A method in which a resin mesh with glass powder attached to its surface or a nonwoven fabric with silica and / or silicate abrasive particle aggregates attached is soaked in water, and the surface to be treated is scrubbed and washed, followed by rinsing with water. etc. By carrying out the polishing step as described above, dirt is removed and the surface to be coated is made smooth, thereby improving the adhesion between the hydrophilic coating agent and the surface to be coated, making it possible to form a film with no unevenness, and enabling the hydrophilicity of the hydrophilic coating agent composition to be more effectively exhibited. The preceding steps of cleaning the target surface and polishing the target surface may be performed alone or in combination. The order of the cleaning and polishing steps may also be arbitrary, but it is preferable to perform the cleaning step before the polishing step in order to efficiently improve the surface smoothness.

[0037] The method for applying the hydrophilic coating composition of the present invention to the surface to be coated is not particularly limited, but for example, (1) A method in which a sponge or nonwoven fabric is impregnated with the hydrophilic coating composition, the composition is uniformly applied to the surface to be coated, and the surface is left to dry. (2) A method in which the hydrophilic coating composition is placed in a spray bottle, the hydrophilic coating composition is sprayed onto the surface to be coated from the spray nozzle, and then the hydrophilic coating composition is thinly spread with a sponge or the like, and then left to dry; etc.

[0038] When applying the hydrophilic coating composition of the present invention to a surface to be coated, 2 It is preferable to apply 0.05 to 2 g per coating. From the viewpoint of the finish of the coating and the durability of hydrophilicity, it is more preferable to apply 0.1 to 1 g. [Example]

[0039] Next, examples will be described together with comparative examples, but the present invention is not limited to these.

[0040] First, to prepare the composition, the following components were prepared. Details of each component are as follows, and the values ​​in Tables 1 to 3 are shown converted to 100% active pure content of each component. Unless otherwise specified, "%" refers to mass basis. Unless otherwise specified, tap water was used as water.

[0041] <Component (A)> Polyvinyl alcohol Product name: J-POVAL JC-40 (average polymerization degree 4000, saponification degree 99.0-99.5) (manufactured by Nippon Vaccination & Poval Co., Ltd.)

[0042] <(B) component> Fluorosurfactants Product name: Capstone FS-60 (reaction product of partially fluorinated alcohol, phosphorus pentoxide, and ammonium salt, active ingredient 26% by mass) (manufactured by The Chemours Company) Silicone surfactants Product name: SILWET L-77 (polyalkylene oxide-modified heptamethyltrisiloxane, active ingredient 61-70% by mass) (Momentive Performance Materials Japan, LLC)

[0043] <(C) component> Water (tap water)

[0044] <(D) component> Nonionic surfactants 1 Product name: Naroacty CL-200 (melting point 42°C) (Polyoxyethylene alkyl ether, alkyl group carbon number C12-15, average number of ethylene oxide added moles 20) (manufactured by Sanyo Chemical Industries, Ltd.) Nonionic surfactants 2 Product name: Naroacty CL-400 (melting point 52°C) (Polyoxyethylene alkyl ether, alkyl group carbon number C12-15, average number of ethylene oxide added moles 40) (manufactured by Sanyo Chemical Industries, Ltd.) Nonionic surfactants 3 Product name: Newpol PE-128 (melting point 62°C) (Polyoxyethylene polyoxypropylene block polymer) (manufactured by Sanyo Chemical Industries, Ltd.) <Reference ingredients> Nonionic surfactants 4 Product name: JCT Ethoxylate 91-6 (liquid at room temperature) (Polyoxyethylene alkyl ether, alkyl group carbon number C9-11, average number of ethylene oxide added moles 6) (manufactured by Oxalis Chemicals Co., Ltd.) Nonionic surfactants 5 Product name: GENAMINOX 1014 (liquid at room temperature) (Alkyldimethylamine oxide, alkyl group carbon number C10-14, active ingredient 32% by mass) (manufactured by Global Amines Japan Co., Ltd.)

[0045] <Optional ingredients> Antibacterial agent 1 Product name: PROXEL IB (Polyhexamethylene biguanide hydrochloride, active ingredient 20% by mass) (Manufactured by Lonza Japan Co., Ltd.) Antibacterial agent 2 Product name: ACTICIDE BAC 50 (Benzalkonium chloride, active ingredient 50% by mass) (manufactured by Thor Japan Co., Ltd.) Enzyme activity inhibitors Product name: Healthy Cu (copper gluconate) (manufactured by Fuso Chemical Co., Ltd.)

[0046] [Examples 1 to 11, Comparative Examples 1 to 3] Hydrophilic coating compositions were prepared according to the compositions shown in Tables 1 to 3 (the units of values ​​in each table are "mass %") and evaluated for finish, film remnant property, and hydrophilicity sustainability. The test methods and evaluation criteria for each item are as follows:

[0047] [Finishing quality] The coating was applied to a porcelain toilet bowl (INAX C180-NC, manufactured by LIXIL Corporation) that had been glazed and fired using the test method described below, and the finish of the coating was evaluated according to the following criteria. Testing Method (1) The coating composition was applied to the surface of the toilet bowl, smoothed with a sponge, and then allowed to dry naturally to form a film (100 m 2 (Approximately 0.2g per serving). (2) The finish state of the coating was visually inspected and judged according to the following evaluation criteria. Evaluation criteria ◯: The uniform glossiness of the toilet bowl is not impaired. △: There is a glossy appearance but it is slightly uneven, or there is little glossy appearance but it is uniform. ×: Gloss is lost and there is unevenness.

[0048] [Film persistence] The film formed on the test piece was rinsed repeatedly with water, and the film remnant property was evaluated according to the following evaluation criteria. Testing Method (1) 0.5 g of the coating composition was applied to a glass plate (76 mm × 52 mm) of known weight, and the applied coating composition was spread evenly with a paper towel. The plate was then placed on a horizontal surface and allowed to dry naturally at room temperature to prepare a test piece. The weight of the test piece before rinsing was measured. (2) The test piece was placed on a horizontal surface, and 70 g of tap water was poured over the test piece from 10 cm above it for 10 seconds. The test piece was allowed to dry naturally at room temperature, and the weight of the test piece after rinsing was measured. (3) The above step (2) was repeated five times, and the residual rate of the active ingredient was calculated using the following formula. TIFF0007747304000001.tif19143 · Weight of glass plate before coating composition: Wg Weight of test piece before rinsing: Wb Weight of test piece after rinsing: Wa (4) Evaluation was based on the following criteria. Evaluation criteria ○:Residual rate 70% or more △: Residual rate 40% or more, less than 70% ×: Residual rate less than 40%

[0049] [Hydrophilic sustainability 1] The test pieces prepared in the above finish test were repeatedly rinsed with water to evaluate the durability of the hydrophilicity of the coated surface. Testing Method (1) The test piece prepared in the above finish test was placed on a horizontal surface, and 180 g of tap water was poured over the test piece from 10 cm above for 10 seconds, and then the test piece was allowed to dry naturally at room temperature. (2) The above step (1) was repeated, and the wet state of the applied surface was visually confirmed during rinsing. The durability of hydrophilicity was judged according to the following evaluation criteria based on the number of rinses required until the surface was repelled and hydrophilicity was lost. Evaluation criteria ○: Maintained hydrophilicity even after rinsing 20 times or more △: Hydrophilicity disappeared after rinsing 10 to 20 times ×: Hydrophilicity was lost after less than 10 rinses

[0050] [Hydrophilic sustainability 2] The hydrophilic coating composition was applied to a washstand in a public restroom, and the durability of the hydrophilicity of the applied surface was evaluated. Testing Method (1) A crystal mesh (polyester mesh, glass powder, synthetic resin adhesive) (manufactured by Let's Create Co., Ltd.) was impregnated with water and polished onto the washbasin of a public restroom. Then, a clean mesh (polyester mesh) (manufactured by Let's Create Co., Ltd.) was used for finishing polishing. After that, 2.5 g of the coating composition was applied to the washbasin (approximately 1900 cm 2 ) and spread evenly using a paper towel, then allowed to dry naturally. (2) The condition of the surface of the washbasin was visually checked every two hours, and the duration of hydrophilicity was judged according to the following evaluation criteria based on the time it took for the surface to repel water and lose its hydrophilicity. Evaluation criteria ◎: 12 hours or more ○: 6 hours or more, less than 12 hours △: 4 hours or more, less than 6 hours ×: Less than 4 hours

[0051] [Table 1]

[0052] [Table 2]

[0053] [Table 3]

[0054] The evaluation results in Tables 1 to 3 show that Examples 1 to 11 achieved almost good results in terms of finish, film remaining property, and sustained hydrophilicity. In contrast, Comparative Examples 1 to 3 have practical problems in at least some of the items.

[0055] The hydrophilic coating composition of the example maintained its film even when exposed to hand soap or rinse water during actual use. The hydrophilicity lasted longer than that of the comparative example coating composition, and the number of cleanings required per day was reduced compared to the comparative example. [Industrial Applicability]

[0056] The hydrophilic coating composition of the present invention can produce a film that has both a glossy and uniform appearance and hydrophilicity, and the hydrophilicity and antifouling properties of the coated surface last for a long time, making it ideal for reducing the frequency of toilet cleaning in facility maintenance.

Claims

1. (A) component, polyvinyl alcohol; As the component (B), a fluorine-based surfactant and / or a silicone-based surfactant, and (C) component, water, Component (D) is a nonionic surfactant having a melting point of 40 to 70°C. A hydrophilic coating composition for antifouling cleaning, comprising:

2. A hydrophilic treatment method comprising a pre-step of cleaning a surface to be coated with the antifouling hydrophilic coating composition for cleaning according to claim 1 before coating the surface.

3. 3. The hydrophilic treatment method according to claim 2, wherein the pre-processing step includes a step of cleaning the surface to be coated with an acidic cleaning agent.

4. 4. The hydrophilic treatment method according to claim 2, wherein the pre-processing step includes a step of polishing the surface to be coated.

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