Water-polluting super-water-repellent coating agent for toys and manufacturing method

Abstract

To provide a super water-repellent coating agent that can easily create a super water-repellent coating that forms water bead and is friendly to the environment and the human body, and to provide a toy in which the super water-repellent coating is used.SOLUTION: A super water-repellent coating agent that forms a super water-repellent coating on the surface of a different substrate is a non-fluorine-based super water-repellent coating agent comprising a chain-shaped hydrophilic silica nanoparticle (A), an alcoholic solvent (B), water (C), a first silane (D), a second silane (E), a silane hydrolysis catalyst (F) and an adhesive (G). A water bead toy using the super water-repellent coating agent comprises at least an application tool (T2), a drip tool (T3), and a coloring solution (T4) using the super water-repellent coating agent (T1).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a water-bead forming super-water-repellent coating for toys and a method of making the same. [Background technology]

[0002] Generally, toys that form soap bubbles and are used for playing are widely used, but there are hardly any inventions relating to toys that form water polka dots and are used for playing. Patent Document 1 discloses a toy in which, when a boat is floated on the water, the chimney moves up and down, allowing water balls to continuously squirt upward from inside.

[0003] Patent Document 2 describes a running toy that can reliably eject water droplets by supplying an appropriate amount of liquid for generating water droplets to a water droplet generating mechanism.

[0004] Patent Document 3 describes a toy in which a water droplet transfer path is formed on a surface that has been given a hydrophobic flocking finish, and water droplets formed by dripping using a dropper, for example, are transferred to this transfer path.

[0005] Patent Document 4 describes a game toy in which a water-repellent layer is formed by applying a chemical agent in which hydrophobic silica is dispersed in an organic solvent-soluble resin such as a urethane resin or an acrylic ester resin to the inside of a frame, and water dripped onto the water-repellent layer turns into droplets that can be played with.

[0006] In nature, water droplets on lotus leaves are known to roll and bounce. The reason why these water droplets are formed is that the surface of the lotus leaf has a hydrophobic uneven structure on the nano-micrometer scale, which strongly repels water. This is called the lotus effect. In particular, a surface is said to be superhydrophobic when the water contact angle is 150° or more and the sliding angle is 10° or less.

[0007] To create a superhydrophobic surface on which water droplets can easily roll off, a technique that combines the use of low surface energy materials and the design of a nano- and micro-scale dual surface texture structure is required. Two types of water-repellent materials are mainly used as low surface energy materials: fluorine-based resins and silicone-based resins. A common method to fabricate nano- and micro-scale dual-surface textures is to use inorganic nanoparticles such as silica, titanium dioxide, zinc oxide, and calcium carbonate. The method for producing an ultra-water-repellent surface is to dissolve a water-repellent resin in a solvent, disperse inorganic nanoparticles in the resulting suspension, coat the surface of a substrate, and dry or heat treat the surface.

[0008] Non-Patent Document 1 reports a method in which silica nanoparticles that have been hydrophobized by a silane coupling treatment are dispersed in an ethanol solvent to obtain a suspension, and then a superhydrophobic coating film is formed on a glass substrate by a spray coating method.

[0009] Non-Patent Document 2 reports a method for modifying the surface of chain-like hydrophilic silica nanoparticles dispersed in ethanol by hydrolysis of two silanes, tetraethoxysilane (TEOS) and triethoxy-1H,1H,2H,2H-heptadecafluorodecylsilane (HDFTES), to form an ultra-water-repellent coating film on the target surfaces of glass, metal, and resin.

[0010] Non-Patent Document 3 reports a method in which silica nanoparticles that have been hydrophobized with 3-aminopropyltriethoxysilane (APTES) are dispersed in absolute ethanol, and dodecyltrimethoxysilane (DDTMS) is added as a surface modifier for the silica nanoparticles and epoxy resin as an adhesive together with a polyamide hardener to prepare a paint-like suspension, thereby forming a durable, superhydrophobic coating on glass or stainless steel substrates. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Utility Model Application Publication No. 54-75896

[0012] [Patent Document 2] JP 2006-102349 A

[0013] [Patent Document 3] Japanese Utility Model Application Publication No. 59-64195

[0014] [Patent Document 4] JP 2017-209132 A [Non-patent literature]

[0015] [Non-Patent Document 1] Hitoshi Ogihara, J.Vac.Soc.Jpn.58, (2015), 431

[0016] [Non-Patent Document 2] Ge DTet al.,Part.Part.Syst.Charact.31,(2014),763

[0017] [Non-Patent Document 3] Zhang ZHet al.,Scientific Reports,8,(2018),3869 Summary of the Invention [Problem to be solved by the invention]

[0018] With conventional toys that use polka dots, the way the polka dots appear is limited by the structure of the toy, so players cannot make the polka dots however they like.

[0019] The method described in Non-Patent Document 1 makes it possible to easily form a super-water-repellent coating film, but its applications are limited. Or the durability is insufficient. Non-Patent Document 2 is capable of forming a super-water-repellent coating film on various target surfaces such as glass, metal, and resin, and contains a fluorine-based resin (HDFTES) as a hydrophobic component. However, fluorine-based water repellents contain the impurity PFOA (perfluorooctane), which is difficult to decompose. Due to concerns about the adverse effects of PFOA accumulation in the human body and residual residue in the external environment, countries around the world have been tightening their regulations on fluorine-based water repellents in recent years. In Japan, PFOA-related substances will be designated as Type 1 specified chemical substances under the Chemical Substances Control Law from December 2020, and both their use and import will be prohibited. Non-Patent Document 3 is capable of forming a strong super-water-repellent coating film because it contains an epoxy resin, but the coating film formed lacks transparency.

[0020] Many super-water-repellent materials have been developed to date, but because the uneven surface structure of the super-water-repellent coating film is extremely fine, the surface structure can easily collapse when subjected to external mechanical pressure, causing the super-water-repellent properties to be lost. For this reason, durability is a major issue for the practical use of many superwater-repellent materials. [Means for solving the problem]

[0021] First, the inventors used hydrophilic silica nanoparticles (A) that are chain-like rather than spherical, and by hydrophobically modifying the surface of the silica nanoparticles using alcohol (B), purified water (C), and two types of silane agents (D and E), they created an ultrahydrophobic suspension that can be applied to any substrate. Furthermore, we discovered an adhesive (G) that can maintain the super-water-repellent properties of the coating, while also improving transparency, water resistance, and adhesion.

[0022] Furthermore, by using ammonia water (F) as a catalyst for the hydrolysis of silane, it has become possible to provide a water-polluting, super-water-repellent coating agent for toys.

[0023] The chain-like hydrophilic silica nanoparticles (A) are chain-like with a short diameter of 5 nm to 30 nm and a long diameter of 20 nm to 200 nm. It is more preferable that the minor axis is 10 nm to 15 nm and the major axis is 40 nm to 100 nm. The chain-like hydrophilic silica nanoparticles (A) may be in the form of a powder or colloidal silica. When colloidal silica is used as the raw material, the content of silica nanoparticles is preferably 15 wt% or more, and the concentration of silica nanoparticles relative to the total amount blended is set to 0.10 to 5.00 wt%. It is more preferable that the content is 0.10 to 1.50 wt %.

[0024] The alcohol (B) may be any one of methanol, ethanol, and isopropyl alcohol (IPA) or a combination of two or more of them, with ethanol being more preferred. The blending amount of the alcohol (B) is 60 to 90 wt %, and more preferably 75 to 85 wt %.

[0025] The volume ratio (C / B) of purified water (C) to alcohol (B) is 1 / 10 to 1 / 5.

[0026] The first silane (D) is tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS), and the blending amount is preferably 0.05 to 3.00 wt%, more preferably 0.15 to 1.00 wt%.

[0027] The second silane (E) is a silane compound represented by the following general formula (E-1). Examples include hexyltrimethoxysilane (n=5) (HTMS), dodecyltrimethoxysilane (n=11) (DDTMS), hexadecyltrimethoxysilane (n=15) (HDTMS), octadecyltrimethoxysilane (n=17) (ODTMS), hexyltriethoxysilane (n=5) (HTES), dodecyltriethoxysilane (n=11) (DDTES), hexadecyltriethoxysilane (n=15) (HDTES), and octadecyltriethoxysilane (n=17) (ODTES). The amount of the second silane (E) is 0.01 to 1.50 wt%, and more preferably 0.05 to 1.00 wt%.

[0028] [ka] In formula (E-1), R represents a methyl group, a methacryl group, an epoxy group, or an olefin group; R1 represents a methyl group or an ethyl group; n represents the number of divalent hydrocarbon groups, and it is preferable that n is 5 or more.

[0029] When R1 of the second silane (E) is a methyl group, the mass ratio (E / D) to the first silane (D) is 1 / 6 Set it to ~1x. It is more preferable that the ratio is 1 / 4 to 1 / 2.

[0030] Ammonia water (F) is used as a catalyst for silane hydrolysis. The concentration of the aqueous ammonia (F) is not particularly limited, but is preferably 28% to 30%. The blending amount is 0.1 to 10.0 wt%, and more preferably 0.5 to 5.0 wt%, calculated as 28% aqueous ammonia.

[0031] The adhesive (G) is preferably a water-soluble polyacrylic acid (PAA) having a molecular weight of 10,000 or more, or polyvinyl butyral (PVB) which is poorly soluble in water but easily soluble in ethanol, and more preferably has a molecular weight of 20,000 or more. The adhesives may be used alone or in combination.

[0032] Regarding the method of dissolving the adhesive (G), water-soluble polyacrylic acid (PAA) may be dissolved in water in advance and mixed as an aqueous solution. Water-insoluble polyvinyl butyral (PVB) may be mixed by preparing an ethanol solution using ethanol in advance.

[0033] The compounding ratio (G / A) of the adhesive (G) to the chain-like hydrophilic silica nanoparticles (A) is 1 / 100 to 3 times, and more preferably 1 / 20 to 1 / 2 times.

[0034] In the first step of the method for producing the superwater-repellent coating agent of the present invention, chain-like hydrophilic silica nanoparticles (A) are added and dispersed in alcohol (B) while stirring the alcohol (B) at 400 rpm or more. The stirring time is preferably 5 minutes or more, and more preferably 10 minutes or more. Next, in the second step, the first silane (D) and the second silane (E) are added in that order to the first step solution, and the mixture is stirred for preferably 5 minutes or more, more preferably 10 minutes or more. In the third step, purified water (C), adhesive (G), and aqueous ammonia (F), a catalyst for silane hydrolysis, are added to the second step liquid in that order, and the mixture is stirred for at least 4 hours. It is more preferable to carry out the treatment for 24 hours or more.

[0035] To remove ammonia, a catalyst for silane hydrolysis, DeodorizationThe fourth step is carried out as the process. Deodorization is performed by a bubbling method at temperatures of 30°C or higher, preferably 50°C or higher.

[0036] The method of application of the superwater-repellent coating agent of the present invention is not particularly limited, and application can be by brushing, dipping, or spraying. However, spray application is more preferable in order to form a superwater-repellent coating film of any shape and on the surface of any material.

[0037] The drying conditions for the ultra-water-repellent coating film are not particularly limited. Drying may be carried out naturally, using a dryer, or using a drying device. In the case of natural drying, the drying time is preferably 4 hours or more, and most preferably 24 hours or more. After drying, water droplets can be intermittently dropped onto the superwater-repellent coating film from a dropper, syringe, drip bottle, etc. to obtain water droplets. Effect of the Invention

[0038] The superwater-repellent coating agent of the present invention can produce a superwater-repellent coating film that forms water droplets with a contact angle of 150° or more and a sliding angle of 10° or less on the surface of glass, ceramics, porcelain tile, fired tile, metal, wood, plastic, paper, and cloth of any shape. Furthermore, the super-water-repellent coating film that was created is transparent, has good adhesion, and can maintain its water-repellent properties for a long time. [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic structure of a super-water-repellent coating formed using the super-water-repellent coating agent of the present invention. [Diagram 2] FIG. 1 is a flow chart showing a method for producing a superwater-repellent coating agent according to the present invention. [Diagram 3] Photographs comparing the difference in the shape of water droplets formed when water droplets are dropped onto a glass surface sprayed with the super-water-repellent coating agent of the present invention and an uncoated glass surface. [Figure 4] 1 is a photograph comparing the difference in the shape of water droplets formed when water droplets are dropped onto a tile surface sprayed with the superwater-repellent coating agent of the present invention and an uncoated tile surface. [Diagram 5]1 is a photograph comparing the difference in the shape of water droplets formed when water droplets are dropped onto a wood surface sprayed with the superwater-repellent coating agent of the present invention and an uncoated wood surface. [Figure 6] Photographs comparing the difference in the shape of water droplets formed when water droplets are dropped onto a cardboard surface spray-coated with the superwater-repellent coating agent of the present invention and an uncoated cardboard surface. [Figure 7] The following shows the results of an adhesion test of a superhydrophobic coating film. After a superhydrophobic coating film was spray-coated onto a glass slide, adhesive tape was attached to half of the surface (photo (a)), and after the adhesive tape was removed, water droplets were dripped onto the area with and without the adhesive tape, and the shapes of the water droplets formed were observed (photo (b)). [Figure 8] The results of a hot water immersion test of an ultra-water-repellent coating film are shown below. After a super-water-repellent coating film was spray-coated on a slide glass, half of the surface was immersed in hot water, and then droplets were dropped onto both the immersed and non-immersed parts, to observe the shapes of the water droplets that formed (c), and after a super-water-repellent coating film was formed on a slide glass, half of the surface was immersed in hot water, and then droplets were dropped onto both the immersed and non-immersed parts, to observe the shapes of the water droplets that formed (d). [Figure 9] 1 is a photograph showing an example of a polka dot forming toy coated with the superwater-repellent coating agent of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] <Super water-repellent coating agent component> Hereinafter, an embodiment of the present invention will be described in detail, but the present invention is not limited thereto. As shown in Figure 1, the superwater-repellent coating film formed by the superwater-repellent coating agent of this embodiment is made of silica nanoparticles with hydrophobic surfaces, and the silica nanoparticles are bonded together and between the silica nanoparticles and the substrate surface with an adhesive, improving the water resistance and adhesion of the superwater-repellent coating film.

[0041] The chain-like hydrophilic silica nanoparticles (A) used in this embodiment are a material for forming a fine uneven structure required to impart super-water repellency to the surface of a substrate. Increasing the amount of the compound can improve the water repellency of the superhydrophobic coating film, but if it is added in an amount of 5% or more, the coating film becomes cloudy and opaque.

[0042] The alcohol (B) is a solvent for dissolving and dispersing the chain-like, hydrophilic silica nanoparticles (A).

[0043] Purified water (C) is a component necessary for the hydrolysis reaction of the first silane (D) and the second silane (E), which chemically modifies the surface of the chain-like, hydrophilic silica nanoparticles (A). The amount of purified water (C) should be 1 / 10 to 1 / 5 times the volume ratio to alcohol (B) (C / B). If the amount exceeds 1 / 5, the dispersibility of the chain-like, hydrophilic silica nanoparticles (A) will deteriorate, resulting in a decrease in uniformity and transparency.

[0044] The first silane (D) used in this embodiment is intended to partially modify the surface of the chain-like, hydrophilic silica nanoparticles (A) with hydrophilic silanol groups (≡Si—OH), and is preferably tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS). For example, when TEOS is used, the chemical reaction for modifying the surface of silica particles with silanols under alkaline conditions is thought to occur through the following process. Si(OCH 2 CH 3 ) 4 + 4H 2 O → Si(OH) 4 + 4CH 3 CH 2 OH (1) Silica particles - (OH) x + Si(OH) 4 → Silica particles - Si(OH) 4ーX + xH 2 O (2)

[0045] The above reaction (1) is called the hydrolysis reaction of TEOS, and the above reaction (2) is called the silylation reaction between the silanol generated by the hydrolysis of TEOS and the silica surface. At the same time as the above reaction (2) occurs, the following dehydration condensation reaction of silanol (3) also occurs. nSi(OH) 4 → nSiO 2 + 2nH 2 O (3)

[0046] The amount of the first silane (D) added is 0.05 to 3.00 wt % based on the total amount of the mixture. A specific example of a TEOS product is KBE-04 manufactured by Shin-Etsu Chemical Co., Ltd.

[0047] The second silane (E) partially modifies the surface of the chain-like, hydrophilic silica nanoparticles (A) with silanol groups having hydrophobic hydrocarbon chains, and is a silane compound represented by the following general formula (E-1). [ka] In formula (E-1), R represents a methyl group, a methacryl group, an epoxy group or an olefin group, R1 represents a methyl group or an ethyl group, and n represents the number of divalent hydrocarbon groups, preferably n=5 or more.

[0048] When DDTMS is used as the second silane (E) in this embodiment, the silylation reaction with silanols on the surfaces of silica particles under alkaline conditions is believed to occur via the following process. CH 3 (CH 2 ) 11 -Si(OCH 3 ) 3 + 3H 2 O → CH 3 (CH 2 ) 11 -Si(OH) 3 + 3CH 3 OH (4) CH 3 (CH 2 ) 11 -Si(OH)3 +Silica particles-(OH) x → CH 3 (CH 2 ) 11 -Si(OH) 3―x -Silica Nanoparticles+ xH 2 O(5)

[0049] Aqueous ammonia (F) is used as a catalyst for the hydrolysis of silane.

[0050] The adhesive (G) is prepared by dissolving water-soluble polyacrylic acid (PAA) in purified water or polyvinyl butyrate (PVB) in alcohol (B). Polyacrylic acid (PAA) and polyvinyl butyral (PVB) may be used alone or in combination. As the amount of adhesive (G) added increases, the water resistance and adhesion of the superhydrophobic coating layer improve, but transparency decreases.

[0051] <Method of manufacturing ultra-water-repellent coating agent> FIG. 2 is a flow diagram showing the method for producing the ultrawater-repellent coating agent according to this embodiment.

[0052] Add alcohol (B) to a manufacturing vessel and, while stirring, add chain-like hydrophilic silica nanoparticles (A) to disperse them (Step 1). Add the first silane (D) and the second silane (E) to the first step solution and dissolve them. (Second step) Add purified water (C), adhesive (G) and ammonia water (F) to the second step solution. (Third step) After the reaction is completed, the ammonia used as the silane hydrolysis catalyst is removed (fourth step).

[0053] The order of adding raw materials in each step in the production method of this embodiment is not particularly limited, but in the second step of the production method, the order is preferably the first silane (D) → the second silane (E). In the third step of the production method, the order of the additives is preferably purified water (C), adhesive (G), and ammonia water (F).

[0054] In the three steps of the manufacturing method of this embodiment, the stirring speed has a significant effect on the dispersibility of the chain-like hydrophilic silica nanoparticles (A) and the hydrolysis rate and dehydration condensation rate of the first silane (D) and the second silane (E), so the stirring speed is 400 rpm or more, and 800 rpm or more is more preferable.

[0055] In the first step of the manufacturing method of this embodiment, in order to thoroughly disperse the chain-like hydrophilic silica nanoparticles (A) in the alcohol (B), the stirring time is preferably 5 minutes or more, and more preferably 10 minutes or more. In the second step, in order to completely dissolve the first silane (D) and the second silane (E) in the alcohol (B) dispersion of the chain-like hydrophilic silica nanoparticles (A) from the first step, the stirring time is preferably 5 minutes or more, and more preferably 10 minutes or more. The third step is to chemically modify the surface of the chain-like, hydrophilic silica nanoparticles (A) by inducing hydrolysis and condensation of silane. In order to complete the silane hydrolysis and condensation reaction, purified water (C), ammonia water (F), which is a catalyst for silane hydrolysis, and an adhesive (G) are added. The stirring time is 4 hours or more, and more preferably 24 hours or more.

[0056] In addition, the fourth step is carried out as a deodorizing step to remove ammonia, which is a catalyst for hydrolysis of silane, from the third step liquid. The fourth step is carried out by a bubbling method at a temperature of 30° C. or higher, and more preferably at 50° C. or higher.

[0057] <Method of forming ultra-water-repellent coating film> There are no particular limitations on the drying conditions for the ultrawater-repellent coating film formed by the ultrawater-repellent coating agent according to this embodiment, but in the case of natural drying, the drying time is preferably 4 hours or more, more preferably 8 hours or more, and most preferably 24 hours.

[0058] The number of sprays required to coat the ultrawater-repellent coating agent according to this embodiment using a spray application method is preferably six or more times on the same location in the case of glass or ceramic tile. For cardboard or wood, it is recommended to spray 12 or more times. EXAMPLES

[0059] Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these. The liquid compositions and evaluation results of the examples are shown in Table 1.

[0060] [Table 1]

[0061] Example 2 The evaluation results when coating the materials in Figures 3 to 6 with the coating agent are shown in Table 2.

[0062] [Table 2]

[0063] Table 3 shows the liquid composition and evaluation results of the comparative examples.

[0064] [Table 3] Example 1

[0065] A 200 ml triangular beaker was placed on a magnetic stirrer, and 81.48 g of mixed ethanol NPs (ethanol 85.5%, methanol 4.9%, isopropyl alcohol 9.6%) was added and stirred at a stirring speed of 800 rpm for 10 minutes. Then, 2.61 g of colloidal silica solution (IPA-ST-UP [silica concentration 15%]) containing chain-like hydrophilic silica nanoparticles (A) was added and stirred at the same stirring speed for 10 minutes. Then, 0.37 g of the first silane (D) TEOS and 0.13 g of the second silane (E) DDTMS were added and stirred at room temperature for 10 minutes. Then, 12.27 g of purified water (C), 0.78 g of adhesive (G) (PAA: 5 wt% JURYMER AC-10L) and 2.35 g of aqueous ammonia (F) were added and stirred for an additional 24 hours. Thereafter, ammonia in the solution was removed by bubbling at 30°C. 0.5 ml of the prepared coating agent was spread on the surface of a slide glass (75 mm x 25 mm) with a dropper and dried at 40°C for 30 minutes to obtain a coating film on the surface of the slide glass. Example 2

[0066] The method of applying the liquid prepared in Example 1 was changed to spray application, and then the liquid was dried to obtain a coating film on the surface of the slide glass. Example 3

[0067] In Example 1, the second silane (E) was changed from DDTMS to ODTMS to prepare a superwater-repellent coating agent. The prepared coating agent was spread on the surface of a slide glass in the same manner as in Example 1, and then dried to obtain a coating film. Example 4

[0068] Example 3 For the adhesive (G), 0.78 g of PAA (5 wt% Julimer AC-10L) was changed to 0.39 g of PVB (10 wt% Mowital B360H) to create a superwater-repellent coating agent. The coating agent created The solution was sprayed and then dried to obtain a coating film on the surface of the slide glass. Example 5

[0069] Example 4 The amount of adhesive (G) PVB (10 wt% Mowital B360H) was increased from 0.39 g to 1.18 g to create a superhydrophobic coating agent. The coating agent created The solution was spray-coated in the same manner as in Example 4, and then dried to obtain a coating film on the surface of the slide glass. Example 6

[0070] The mixed ethanol NP (ethanol 85.5%, methanol 4.9%, isopropyl alcohol 9.6%) in Example 1 was changed to 99.5% ethanol to prepare a superwater-repellent coating agent. The prepared coating agent was spread on the surface of a slide glass in the same manner as in Example 1, and then dried to obtain a coating film. Example 7

[0071] A super water-repellent coating agent was prepared by changing the TEOS in the first silane (D) in Example 1 to TMOS. The prepared coating agent was spread on the surface of a slide glass in the same manner as in Example 1, and then dried to obtain a coating film.

[0072] Comparative Example 1 A coating agent was prepared by changing the polyacrylic acid (PAA) of the adhesive (G) in Example 1 to polyvinylpyrrolidone (PVP). The prepared coating agent was spread on the surface of a slide glass in the same manner as in Example 1, and then dried to obtain a coating film.

[0073] Comparative Example 2 A coating agent not containing an adhesive (G) was prepared by changing the DDTMS of the second silane (E) in Example 1 to DDTES. The prepared coating agent was spread on the surface of a slide glass in the same manner as in Example 1, and then dried to obtain a coating film.

[0074] Comparative Example 3 Hydrophobic Silica nanoparticles (QSG170), A coating agent was made using alcohol (B) and purified water (C). The prepared coating agent was spread on the surface of a slide glass in the same manner as in Example 1, and then dried to obtain a coating film.

[0075] Comparative Example 4 Hydrophobic Silica nanoparticles (QSG30), alcohol (B), purified water (C) A coating agent was created using the adhesive (G) PVB. The prepared coating agent was spread on the surface of a slide glass in the same manner as in Example 1, and then dried to obtain a coating film.

[0076] The uniformity, adhesion and transparency of the coating film were evaluated according to the following three-level evaluation criteria: S, A and B. Water resistance was evaluated as yes or no. Water repellency was evaluated using a four-level rating scale: S, A, B, and none.

[0077] The contact angle of water was measured by dropping 0.01 mL of water onto the coating film with a syringe, photographing the water droplets formed, and using Image image analysis software.

[0078] <Uniformity of coating film> S: No uncoated areas or white unevenness observed A: It is not noticeable, but there are some areas that are not coated and some white unevenness. B: Uncoated areas and white unevenness are noticeable

[0079] <Water resistance of coating film> Yes: The shape of the water droplets formed on the coating film remains for more than 10 minutes. None: The shape of the water droplets formed on the coating film collapses within 10 minutes.

[0080] <Adhesion of coating film> S: The coating does not come off even when rubbed with fingertips A: The coating comes off when you rub it with your fingertips. B: The coating comes off even when lightly touched with a fingertip

[0081] <Transparency of coating film> S: The white letters written on the black paper in the background are clearly visible through the slide glass, and there is almost no coloring. A: Although the white letters written on the black paper in the background cannot be seen clearly through the glass slide, they can still be distinguished. It is also slightly whiter. B: It is not possible to distinguish white letters written on a black paper background through the glass slide. It's turning white again

[0082] <Water repellency of coating film> S: When a 0.01 mL drop of water is dropped onto a horizontal coating film using a syringe, the drop rolls naturally. This is a superhydrophobic state. A: When a 0.01 mL droplet is dropped onto a horizontal coating film using a syringe, the droplet does not roll naturally. However, when the coating film is tilted to an angle of 10° or less, the droplet begins to roll, resulting in a super-hydrophobic state. B: When a 0.01 mL drop of water is dropped onto a horizontal coating film using a syringe, a drop forms, but the drop does not roll even when the inclination angle is increased to 10° (water-repellent state). In other words, it is water repellent but not super water repellent. None: After dropping 0.01 mL of water onto a horizontal coating film with a syringe, the film loses water repellency after a while.

[0083] <Coating film adhesion test> After the super-water-repellent coating agent of the present invention was applied to the surface of a slide glass and dried, adhesive tape was attached to half of the surface of the slide glass. After that, the adhesive tape was peeled off, and 0.01 mL of water was dropped with a syringe onto the area where the tape had been peeled off and onto the area where the tape had not been attached, and the shape of the water droplets formed was observed. The adhesive tape prevented the super-water-repellent coating film from peeling off, and the super-water-repellent properties were maintained.

[0084] <Hot water resistance test of coating film> After applying the super-water-repellent coating agent of the present invention to the surface of a glass slide and drying it, half of the glass slide was immersed in 40°C hot water for 68 hours, and then 0.01 mL of water droplets were dropped with a syringe onto the part immersed in hot water and the part not immersed in hot water, and the shape of the water droplets formed was observed. Figure 8 (c) In addition, after the superhydrophobic coating agent of the present invention was applied to the surface of a glass slide and dried, half of the glass slide was immersed in hot water at 90°C for 3 minutes, and then 0.01 mL of water droplets were dropped with a syringe onto the part immersed in hot water and the part not immersed in hot water, and the shape of the water droplets formed was observed. (Fig. 8, photo (d)) No deterioration of the superhydrophobic coating film was observed even when immersed in warm water or hot water.

Claims

1. A super-water-repellent coating agent for forming water droplets with a contact angle of 150° or more and a sliding angle of 10° or less on the surface of glass, ceramics, porcelain tiles, fired tiles, metals, wood, plastics, paper, and cloth of any shape, comprising 0.10 to 5.00 wt% hydrophilic silica nanoparticles (A) having an elongated shape with an average short axis of 5 nm to 30 nm and an average long axis of 20 nm to 200 nm, 60 to 90 wt% alcohol (B) selected from methanol, ethanol, and isopropyl alcohol (IPA) or a combination of two or more of them, purified water (C) in a volume ratio to the alcohol of 1 / 10 to 1 / 5, and tetraethoxysilane (TPA) in a volume ratio of 1 / 10 to 1 / 5. A super-water-repellent coating agent for toys, comprising: 0.05 to 3.00 wt % of a first silane (D) which is silane (TEOS) or tetramethoxysilane (TMOS); 0.01 to 1.50 wt % of a second silane (E) which is a non-fluorine-based silane compound represented by the following general formula (E-1); 0.1 to 10.0 wt % of ammonia water (F) converted to a 28% concentration as a catalyst for hydrolysis of the silane; and 1.0 to 300.0 wt % of an adhesive (G) which is a water-soluble polyacrylic acid (PAA) or a water-insoluble polyvinyl butyral (PVB) having a molecular weight of 10,000 or more, either alone or in combination, based on silica nanoparticles (A). 【Chemistry 1】 [In formula (E-1), R represents a methyl group, a methacryl group, an epoxy group, or an olefin group, R1 represents a methyl group or an ethyl group, and n represents the number of divalent hydrocarbon groups, where n is 5 or more.]

2. 2. A superwater-repellent coating agent for toys, characterized in that R1 of the second silane (E) according to claim 1 is a methyl group, and the mass ratio of the second silane (E) to the first silane (D) is 1 / 6 to 1.

3. A method for producing a superwater-repellent coating agent for toys as described in claim 1 or 2, comprising the steps of: a first step of adding and dispersing silica nanoparticles (A) while stirring alcohol (B) at a stirring speed of 400 rpm or more; a second step of adding a first silane (D) and a second silane (E) to the first step liquid and dissolving them; a third step of adding purified water (C), an adhesive (G) and ammonia water (F) as a catalyst for hydrolysis of silane to the second step liquid and stirring for 4 hours or more; and a fourth step of removing the ammonia odor from the third step liquid at 30°C or more by a bubbling method.

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