JP3929328B2 - High water-sliding coating and coating method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention shows extremely excellent water slidability (water droplet slidability) that can be used particularly for architectural window glass, vehicle window glass, mirrors, and other industrial glass, and has high durability. The present invention relates to an aqueous coating and a coating method thereof.
[0002]
[Prior art]
As an attempt to improve water drop sliding properties, a composition containing a silicone-based wax, an organopolysiloxane, a surfactant and the like has been proposed. For example, Japanese Patent Publication No. 50-15473 includes an alkylpolysiloxane and an acid. JP-A-5-301742 discloses a composition containing an amino-modified silicone oil and a surfactant, and a composition that slides with a water droplet amount of about 15 μl at a 30 ° inclination is obtained. Yes. JP-A-11-181212 discloses a unit in which a group such as — (CH ₂ ) ₃ (CF ₂ ) ₇ CH ₃ is directly bonded to a silicon atom forming an organosiloxane unit, and — (CH ₂ ) ₃ SiCl. Disclosed is a surface treatment agent comprising a fluorine-containing silicone compound and / or a partial hydrolyzate product of the compound, in which a group such as ₃ is an essential unit directly bonded to a silicon atom forming an organosiloxane unit As a result, 50 μl of water droplets slide down at an inclination of about 10 °. Japanese Patent Application Laid-Open No. 2000-144056 discloses a silicone compound having a hydrolyzable functional group at the terminal, or a silicone compound having a hydrolyzable functional group at the terminal and a fluoroalkyl group at the other end, and an acid. A functional layer obtained by dissolving water in a solvent, applying the mixed solution obtained by mixing and stirring to the substrate surface, and then drying it is chemically bonded to the substrate surface by a siloxane bond. A surface-treated substrate excellent in water droplet sliding property, which is characterized by the above, is disclosed, in which 50 μl of water droplets slide down at an inclination of about 1 °. These surface treatment agents form a water slidable layer by directly treating the water slidable component on the base material, and are based on a transparent film in which the water slidable component and the matrix component are hybridized as in the present invention. It is not something that is formed on the material.
[0003]
As a method for forming a transparent film comprising a water-sliding component and a matrix component on a substrate, JP-A-8-12375 discloses a mixture of a fluoroalkyl group-containing silane compound and dimethyl silicone and / or a derivative thereof in a solvent. A solution obtained by hydrolysis and a solution obtained by hydrolyzing an alkoxysilane compound in a solvent are mixed, and the mixture is applied to the surface of the substrate. A water-repellent article is disclosed in which methyl groups are present in a higher concentration in the outer surface layer than in the inner layer of the coating. Japanese Patent Application Laid-Open No. 2000-26758 discloses a hydroxyl group-containing vinyl polymer, an epoxy-terminated siloxane polymer, a sulfonic acid compound, an optionally blocked polyisocyanate compound, and a melamine resin as a coating composition capable of forming a water slidable film. With a coating composition capable of forming a water-slidable film containing at least one crosslinking agent component selected from the group consisting of a surfactant selected from the group consisting of a specific dialkylsulfosuccinate and an alkylene oxide silane, the falling angle at a water droplet volume of 10 μl is reduced. It is disclosed that it exhibits excellent performance of 5 ° or less.
[0004]
[Problems to be solved by the invention]
However, the water-repellent article described in Japanese Patent Laid-Open No. 8-12375 has a water drop sliding property of 50 μl of water droplets at a level that slides at an inclination of about 16 °. This level is not enough. Further, the water-repellent article described in JP-A-2000-26758 has low transparency and is limited to use as a paint.
[0005]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and when a fluoroalkylsilane having hydrolyzable groups such as trialkoxy groups at both ends is used, the silica concentration in the coating solution, the silicone concentration (weight relative to silica) Ratio) and fluoroalkylsilane (FAS) concentration, it was found that a highly water-repellent coating with high transparency can be obtained. In addition, the introduction of fluoroalkylsilane improves the durability (light resistance and acid resistance) of the highly water-slidable coating. Since the fluoroalkylsilane having hydrolyzable groups at both ends can be added at a high concentration, the durability of the highly water-slidable coating can be further enhanced.
[0006]
That is, the highly water-slidable coating film of the present invention comprises an alkoxy-terminated dimethyl silicone represented by the general formula [1] and a fluoroalkyl having hydrolyzable groups at both ends represented by the general formula [2] in a silica matrix. It is characterized in that silane is dispersed.
[0007]
[Chemical 3]
[0008]
Here, X is -OR or _{-R'Si (OR) r (CH 3} ) 3-r (R is a monovalent an alkyl group, R 'is an divalent alkylene group) alkoxy group or an alkoxy group represented by The containing group, p, q, and r are integers of 1 to 3, and n is an integer of 2000 or less.
[0009]
[Formula 4]
[0010]
Here, s is an integer of 0 to 12, t and u are integers of 1 to 3, and Z is a hydrolyzable group.
[0011]
The highly water-slidable coating film of the present invention is characterized in that the number of alkoxy groups in the alkoxy-terminated dimethyl silicone represented by the general formula [1] is 3 or more.
[0012]
Furthermore, the highly water-slidable coating film of the present invention is characterized in that the number of hydrolyzable groups of the fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] is 3 or more. To do.
[0013]
Furthermore, the highly water-resistant coating film of the present invention is characterized in that the alkoxy-terminated dimethyl silicone represented by the general formula [1] is present in an amount of 1 to 300% by weight based on silica as a matrix. To do.
[0014]
Furthermore, the highly water-slidable coating film of the present invention is a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2]. The alkoxy-terminated dimethylsilicone represented by the general formula [1]. It exists in the range of 10-3000 mol% with respect to this.
[0015]
Furthermore, the highly water-slidable coating film of the present invention has an alkoxy-terminated dimethyl silicone represented by the general formula [1] and hydrolyzable groups at both ends represented by the general formula [2] in a silica matrix. The component formed by bonding fluoroalkylsilane is dispersed.
[0016]
Furthermore, the highly water-slidable coating film of the present invention is characterized in that it is formed on a base layer made of a metal oxide formed on the substrate surface.
[0017]
Moreover, the coating method of the highly water-slidable coating film of the present invention is characterized by being performed by the following steps.
(1) preparing a silica sol as a matrix component by hydrolyzing and polycondensing alkoxysilane;
(2) An alkoxy-terminated dimethyl silicone represented by the general formula [1], a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2], and the above (1) A step of preparing a coating solution by mixing silica sol,
(3) A step of applying a heat treatment after applying the coating solution on the surface of the substrate.
[0018]
Furthermore, the coating method of the highly water-slidable coating film of the present invention is characterized in that the heat treatment is performed at a temperature of 600 ° C. or lower.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The highly lubricious coating film of the present invention comprises an alkoxy-terminated dimethyl silicone represented by the general formula [1] and a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] in a silica matrix. Is distributed.
[0020]
[Chemical formula 5]
[0021]
Here, X is -OR or _{-R'Si (OR) r (CH 3} ) 3-r (R is a monovalent an alkyl group, R 'is an divalent alkylene group) alkoxy group or an alkoxy group represented by The containing group, p, q, and r are integers of 1 to 3, and n is an integer of 2000 or less.
[0022]
[Chemical 6]
[0023]
Here, s is an integer of 0 to 12, t and u are integers of 1 to 3, and Z is a hydrolyzable group.
[0024]
For example, silica prepared as a silica sol formed by advancing hydrolysis and polycondensation reaction of alkoxysilane can be used as the matrix which is a film constituent of the high water-sliding coating. For example, a predetermined amount of alkoxysilane (for example, tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ]) and a solvent are mixed and stirred (for example, about 30 minutes) to obtain a solution A. In addition, as a solvent, lower alcohols, such as ethyl alcohol and isopropyl alcohol, and those mixed solvents are desirable, However, Ethers and ketones can also be used. On the other hand, the aqueous solution and the solvent are mixed and stirred (for example, about 30 minutes) to obtain a solution B.
[0025]
Next, after mixing the solution A and the solution B, the mixture is stirred for a long time (for example, about 15 hours) at room temperature to proceed hydrolysis and polycondensation reaction of alkoxysilane to obtain a silica sol. As described above, hydrolysis of alkoxysilane can be carried out by adding a small amount of water and an acid catalyst such as hydrochloric acid, nitric acid, acetic acid, etc., using alkoxysilane as a starting material, and heating the hydrolyzate at room temperature or while heating. A silica sol can be obtained by polycondensation by stirring. The method for preparing the silica sol is not limited to the above method, but the method of gradually mixing an acidic aqueous solution diluted with a solvent into a solution obtained by diluting the alkoxysilane as described above with a solvent is abrupt. This is preferable because a more homogeneous reaction can be obtained.
[0026]
Examples of the alkoxysilane include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. , Trialkoxysilanes such as propyltrimethoxysilane and propyltriethoxysilane, or dialkoxysilanes can be used. Among the above alkoxysilanes, trialkoxysilanes such as tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane are preferable.
[0027]
The alkoxy-terminated dimethyl silicone represented by the general formula [1] has at least an alkoxy group capable of bonding with a silica matrix or a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] at each end. What has 1 or more can be used. The number of alkoxy groups possessed by the alkoxy-terminated dimethyl silicone is preferably 3 or more, and if it is 2 or less, the compatibility with silica sol is lowered, and the film formability is lowered. The holding amount is reduced and the durability of the highly water-slidable coating is lowered.
[0028]
The average degree of polymerization n of the alkoxy-terminated dimethyl silicone represented by the general formula [1] is 2000 or less, and particularly preferably in the range of 5 to 1000. When it is 2000 or more, the compatibility with silica sol is lowered, and it becomes difficult to form a transparent film.
[0029]
R in the alkoxy-terminated dimethylsilicone represented by the general formula [1] is a monovalent alkyl group having 1 to 6 carbon atoms, and includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a hexyl group. A group such as a group or a cyclohexyl group can be used. Of these, a methyl group or an ethyl group is preferable. R ′ is a divalent alkylene group having 2 to 4 carbon atoms, and an ethylene group, a propylene group, an isopropylene group, a butylene group, or the like can be used. Among them, an ethylene group is preferable.
[0030]
Furthermore, the alkoxy-terminated dimethyl silicone represented by the general formula [1] is preferably present in the range of 1 to 300% by weight with respect to silica in the coating solution. When the content is 1% by weight or less, the amount of silicone present in the silica film is reduced, and the water slidability of the highly water slidable coating is lowered. On the other hand, if it is 300% by weight or more, the compatibility with the silica sol is lowered and it becomes difficult to form a transparent film.
[0031]
Next, examples of the fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] include Cl ₃ SiCH ₂ CH ₂ (CF ₂ ) ₁₂ CH ₂ CH ₂ SiCl ₃ , Cl ₂ ( _{CH 3) SiCH 2 CH 2 (} CF 2) 12 CH 2 CH 2 Si (CH 3) Cl 2, Cl (CH 3) 2 SiCH 2 CH 2 (CF 2) 12 CH 2 CH 2 Si (CH 3) 2 Cl , Cl ₃ SiCH ₂ CH ₂ (CF ₂ ) ₁₀ CH ₂ CH ₂ SiCl ₃ , Cl ₂ (CH ₃ ) SiCH ₂ CH ₂ (CF ₂ ) ₁₀ CH ₂ CH ₂ Si (CH ₃ ) Cl ₂ , Cl (CH _{3 ) 2 SiCH 2 CH 2 (CF} 2) 10 CH 2 CH 2 Si (CH 3) 2 Cl, Cl 3 SiCH 2 CH 2 (CF 2) 8 CH 2 CH 2 SiCl 3, Cl 2 (CH 3) SiCH 2 CH _{2 (CF 2) 8 CH 2} CH 2 Si (CH 3) Cl 2, _{l (CH 3) 2 SiCH 2} CH 2 (CF 2) 8 CH 2 CH 2 Si (CH 3) 2 Cl, Cl 3 SiCH 2 CH 2 (CF 2) 6 CH 2 CH 2 SiCl 3, Cl 2 (CH 3 _{) SiCH 2 CH 2 (CF 2} ) 6 CH 2 CH 2 Si (CH 3) Cl 2, Cl (CH 3) 2 SiCH 2 CH 2 (CF 2) 6 CH 2 CH 2 Si (CH 3) 2 Cl, Cl ₃ SiCH ₂ CH ₂ CF ₂ CH ₂ CH ₂ SiCl ₃ , Cl ₂ (CH ₃ ) SiCH ₂ CH ₂ CF ₂ CH ₂ CH ₂ Si (CH ₃ ) Cl ₂ , Cl (CH ₃ ) ₂ SiCH ₂ CH ₂ CF _{2 CH 2 CH 2 Si (CH 3} ) 2 Cl, (CH 3 O) 3 SiCH 2 CH 2 (CF 2) 12 CH 2 CH 2 Si (OCH 3) 3, (CH 3 O) 2 (CH 3) SiCH 2 CH ₂ (CF ₂ ) ₁₂ CH ₂ CH ₂ Si (CH ₃ ) (OCH ₃ ) ₂ , (CH ₃ O ) (CH ₃ ) ₂ SiCH ₂ CH ₂ (CF ₂ ) ₁₂ CH ₂ CH ₂ Si (CH ₃ ) ₂ (OCH ₃ ), (CH ₃ O) ₃ SiCH ₂ CH ₂ (CF ₂ ) ₁₀ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , (CH ₃ O) ₂ (CH ₃ ) SiCH ₂ CH ₂ (CF ₂ ) ₁₀ CH ₂ CH ₂ Si (CH ₃ ) (OCH ₃ ) ₂ , (CH ₃ O) (CH ₃ ) _{2 SiCH 2 CH 2 (CF 2)} 10 CH 2 CH 2 Si (CH 3) 2 (OCH 3), (CH 3 O) 3 SiCH 2 CH 2 (CF 2) 8 CH 2 CH 2 Si (OCH 3) 3, (CH ₃ O) ₂ (CH ₃ ) SiCH ₂ CH ₂ (CF ₂ ) ₈ CH ₂ CH ₂ Si (CH ₃ ) (OCH ₃ ) ₂ , (CH ₃ O) (CH ₃ ) ₂ SiCH ₂ CH ₂ (CF _{2) 8 CH 2 CH 2 Si} (CH 3) 2 (OCH 3), (CH 3 O) 3 SiCH 2 CH 2 (CF 2) 6 CH 2 CH 2 S i (OCH ₃ ) ₃ , (CH ₃ O) ₂ (CH ₃ ) SiCH ₂ CH ₂ (CF ₂ ) ₆ CH ₂ CH ₂ Si (CH ₃ ) (OCH ₃ ) ₂ , (CH ₃ O) (CH ₃ ) ₂ SiCH ₂ CH ₂ (CF ₂ ) ₆ CH ₂ CH ₂ Si (CH ₃ ) ₂ (OCH ₃ ), (CH ₃ O) ₃ SiCH ₂ CH ₂ CF ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , (CH _{3 O) 2 (CH 3)} SiCH 2 CH 2 CF 2 CH 2 CH 2 Si (CH 3) (OCH 3) 2, (CH 3 O) (CH 3) 2 SiCH 2 CH 2 CF 2 CH 2 CH 2 Si Examples include (CH ₃ ) ₂ (OCH ₃ ), fluoroalkylethoxysilanes, fluoroalkylpropoxysilanes, fluoroalkylisocyanate silanes, etc., and hydrolyzability represented by Z in the general formula [2]. Groups include methoxy, ethoxy, and prop Shi group, an isopropoxy group, an alkoxy group such as butoxy group, or can be used such as a chloro group or an isocyanate group.
[0032]
Further, the fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] is preferably present in the coating solution in a range of 10 to 3000 mol% with respect to the alkoxy-terminated dimethylsilicone. . When the amount is 10 mol% or less, the amount of fluoroalkylsilane in the silica film is small and the durability of the highly water-slidable coating film is lowered. On the other hand, if it is 3000 mol% or more, the compatibility with the silica sol is lowered and it becomes difficult to form a transparent film.
[0033]
Next, the coating method of the highly water-slidable coating of the present invention will be described.
The highly water-slidable coating film of the present invention can be coated by the following process.
(1) preparing a silica sol as a matrix component by hydrolyzing and polycondensing alkoxysilane;
(2) An alkoxy-terminated dimethyl silicone represented by the general formula [1], a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2], and the above (1) A step of preparing a coating solution by mixing silica sol,
(3) A step of applying a heat treatment after applying the coating solution on the surface of the substrate.
That is, the coating solution for a highly water-slidable coating film contains an alkoxy-terminated dimethyl silicone represented by the general formula [1] and a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2]. It can obtain by adding and mixing.
[0034]
Solvents used above include lower alcohols such as ethyl alcohol and isopropyl alcohol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and butyl acetate, and aromatic hydrocarbon solvents such as toluene, benzene and xylene. It is preferable to use ethers such as diethyl ether and diisopropyl ether, chlorinated solvents such as chloroform and carbon tetrachloride, and mixtures thereof.
[0035]
Next, the coating solution obtained above is applied to the surface of the substrate.
Various coating methods such as hand coating, nozzle flow coating method, dipping method, spray method, reverse coating method, flexo method, printing method, flow coating method or spin coating method, and known coating means such as combinations thereof are applied. Can be adopted as appropriate. It can also be used as a simple type spray-type water repellent agent.
[0036]
Next, the coating solution applied to the substrate surface is heat-treated to fix the coating on the substrate surface.
The heat treatment may be naturally dried by air drying, or after the drying or simultaneously with the drying, the heat treatment may be performed at a temperature exceeding room temperature and 600 ° C. or less. If the temperature exceeds 600 ° C., the water-sliding component is thermally decomposed and the water-sliding property is remarkably lowered.
[0037]
The base material is not particularly limited, such as glass and plastic. For example, in the case of a glass substrate, a float glass or a roll-out that is usually used for architectural window glass or automobile window glass is used. Inorganic transparent plate glass such as glass produced by the method is preferred, and it is not particularly limited to colorless or colored, as well as its type or color tone, combination with other functional films, glass shape, etc. As a bent plate glass, of course, it can be used as various tempered glasses, strength-enhanced glass, flat plate or single plate, and can also be used as double-layer glass or laminated glass. The coating may be formed on both sides of the glass substrate.
[0038]
In addition, the base layer which consists of a metal oxide may be provided in the base-material surface where a synovial fluid is apply | coated. For example, in the case of a glass substrate, the underlying layer is preferably an oxide thin film containing a metal oxide such as silicon oxide as a main component, and the coating liquid is applied thereon to cover the highly water-slidable film. Thus, a highly lubricious glass having high durability can be obtained.
[0039]
As described above, the highly water-slidable coating of the present invention has a silicon matrix having an alkoxy group bonded to a silica matrix and a dimethyl silicone having both ends of the dimethylsiloxane chain bonded to each other via oxygen or methylene groups. Since a composition comprising a fluoroalkylsilane having a hydrolyzable group is used as the water-sliding component, the retention of the water-sliding component in the matrix is improved, and further, the fluoroalkyl having excellent durability in the matrix By introducing silane, a highly durable and highly lubricious coating film can be formed.
[0040]
In the present invention, the water slidability is a method as described in the evaluation method of the examples described later, that is, after dropping 50 μl of pure water on the sample surface, the sample is gradually tilted, and the water droplets move. Evaluation was made by measuring the angle of inclination at the beginning. In addition, this inclination angle was made into the fall angle (degree), and the fall angle was measured in air | atmosphere (about 25 degreeC) using Kyowa Interface Science CA-A type | mold. In addition, the high lubricity of this invention means a thing with a fall angle of 10 degrees or less.
[0041]
【Example】
Examples of the present invention will be described below. The present invention is not limited to these examples. In addition, the evaluation method of a highly lubricious coating film is shown below.
[0042]
[Evaluation of high water-sliding film]
The evaluation method of the highly water-slidable coating is described below.
(1) Contact angle The angle formed by the water droplet and the sample surface when about 2 μl of pure water was placed on the sample surface having a highly water-slidable coating was measured with a contact angle meter. In addition, the CA-X type made from Kyowa Interface Science was used for the contact angle meter, and it measured in air | atmosphere (about 25 degreeC).
(2) Falling angle With the sample held horizontally, after dropping 50 μl of pure water onto the sample surface, the sample is gradually tilted, and the tilt angle at the time when the water droplet starts to move is defined as the falling angle (°). did. The sliding angle was measured in the atmosphere (about 25 ° C.) using Kyowa Interface Science CA-A type. A falling angle of 10 ° or less was regarded as acceptable.
(3) Acid resistance test 1 ml of 25% sulfuric acid aqueous solution was dropped on the surface of the sample and left at about 25 ° C. for 24 hours. Next, the surface was washed with tap water and air-dried, and then the contact angle and the falling angle were evaluated.
(4) Light resistance test The contact angle and the falling angle after 12 h irradiation of a 1.5 kW metal halide lamp (manufactured by Eye Graphics, M015-L312) were evaluated.
[0043]
Example 1
(1) Preparation of mixed solution of fluoroalkylsilane having hydrolyzable groups at both ends and alkoxy-terminated dimethylsilicone FIG. 1 shows a fluoroalkylsilane having hydrolyzable groups at both ends (hereinafter “hydrolyzable groups at both ends”). The preparation procedure and mixing ratio (weight ratio) of a mixed solution consisting of “containing FAS” and alkoxy-terminated dimethyl silicone are shown.
First, an alkoxy-terminated dimethyl silicone diluted with ethyl acetate to 10 wt% and having an average polymerization degree n of 200 [(CH ₃ O) ₃ SiCH ₂ CH ₂ Si (CH ₃ ) ₂ O [Si (CH ₃ ) ₂ O] ₂₀₀ Si (CH ₃ ) ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ] solution; 3.90 g and ethyl acetate; 21.30 g and 0.1 mol / l nitric acid aqueous solution; 0.02 g were mixed and mixed at room temperature for about 5 hours. After stirring, molecular sieve (Union Showa, 4AXH-5 8 × 12); 4.20 g was added and allowed to stand at room temperature for about 20 hours to remove water in the reaction solution to obtain Solution A.
Next, solution A; 22.20 g and 3,3,4,4,5,5,6,6,7,7,8,8-dodecafluoro-1,10-bis (trimethoxysilyl) decane [(CH ₃ O) ₃ SiCH ₂ CH ₂ (CF ₂ ) ₆ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ]; 0.05 g was mixed and stirred at room temperature for about 24 hours to obtain FAS and alkoxy containing both terminal hydrolyzable groups A mixed solution X of terminal dimethyl silicone was obtained.
[0044]
(2) Preparation of silica sol The silica sol was prepared by advancing hydrolysis and polycondensation reaction of tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ : TEOS]. FIG. 2 shows the silica sol preparation procedure and the mixing ratio (weight ratio) of each component.
First, TEOS; 312.5 g and Echinen F1 (mixture of lower alcohol composed of 90 wt% ethanol and 10 wt% isopropyl alcohol); 40.0 g were mixed and stirred for about 30 minutes to obtain Solution B. Moreover, 0.1 mol / l nitric acid aqueous solution; 7.5 g, H ₂ O; 210.0 g and echinene F1; 20.0 g were mixed and stirred for about 30 minutes to obtain a solution C. Next, after mixing Solution B and Solution C, silica sol Y was obtained by stirring at room temperature for about 15 hours.
[0045]
(3) Preparation of Coating Solution A coating solution was obtained by mixing the mixed solution X of the above-mentioned hydrolyzable group-containing FAS and alkoxy-terminated dimethyl silicone with the silica sol Y. FIG. 3 shows the procedure for preparing the coating solution and the mixing ratio (weight ratio) of each chemical solution.
First, mixed solution X of FAS containing both terminal hydrolyzable groups and alkoxy-terminated dimethyl silicone; 1.46 g and methyl ethyl ketone; 3.00 g and isopropyl alcohol; 3.00 g were mixed and stirred for about 5 minutes. Next, 0.39 g of the above silica sol Y was added and stirred at room temperature for about 15 hours. Next, 13.5 g of methyl ethyl ketone and 13.5 g of isopropyl alcohol were added and stirred for 30 minutes. By the above method, the silica concentration is 0.1% by weight, the weight ratio of alkoxy-terminated dimethyl silicone to silica (hereinafter referred to as “silicone concentration”) is 62.5% by weight, and both terminal hydrolyzability to alkoxy-terminated dimethyl silicone. A coating solution for a highly lubricious coating film having a molar ratio of group-containing FAS (hereinafter referred to as “FAS concentration”) of 400 mol% was prepared.
[0046]
(4) Cleaning of glass substrate The surface of a float glass having a size of 300 mm × 300 mm × 2 mm (plate thickness) was polished with a polishing liquid, washed with water and dried with a glass cleaning machine (produced by our company). In addition, the polishing liquid used here was a suspension obtained by mixing approximately 1% of a glass polishing agent Mille E (manufactured by Mitsui Mining Co., Ltd.) with water.
[0047]
(5) Coating of highly water-slidable coating film The coating solution prepared in (3) above was applied on the glass substrate prepared in (4) above by spin coating. First, the glass substrate, which is a glass substrate for a coating film, is placed on a spin coater, and about 25 to 30 ml of coating solution is dropped while rotating at a rotation speed of 100 rpm, and the coating is applied while maintaining the rotation speed for 30 seconds. The film was dried to obtain a transparent gel film having good film formability. Next, heat treatment was performed at 280 ° C. for 10 minutes, and the mixture was cooled to room temperature, then washed with running water (Cotton No. 300) and air-dried to obtain a glass sample with a highly lubricious coating film.
[0048]
As a result of evaluating the initial performance and durability of the glass sample with a high water slidable film obtained by the procedure described in [Evaluation of water slidable film], the initial contact angle was as good as 108 ° and the initial sliding angle was 5 °. It exhibited water drop slidability. The contact angle after the acid resistance test was 89 °, the tumbling angle was 12 °, the contact angle after the light resistance test was 88 °, and the tumbling angle was 13 °, maintaining high water repellency.
The production conditions of the samples produced in Examples and Comparative Examples are shown in Table 1, and the initial performance and durability test results are shown in Table 2.
[0049]
[Table 1]
[0050]
[Table 2]
[0051]
Example 2
In the same manner as in Example 1, a coating solution having a silicone concentration of 50.0% by weight and a FAS concentration of 200 mol% was prepared.
As a result, the initial contact angle was 106 ° and the initial drop angle was 6 °, indicating a good drop drop property. The contact angle after the acid resistance test was 81 °, the drop angle was 17 °, and the contact angle after the light resistance test was 80. The water repellency was maintained as high as 18 °.
[0052]
Example 3
Alkoxy-terminated dimethyl silicone having an average degree of polymerization n of 150 [(CH ₃ O) ₃ SiCH ₂ CH ₂ Si (CH ₃ ) ₂ O [Si (CH ₃ ) ₂ O] ₁₅₀ Si (CH ₃ ) ₂ CH ₂ CH ₂ Si All were the same as Example 1 except that (OCH ₃ ) ₃ ] was used.
As a result, the initial contact angle was 106 ° and the initial drop angle was 8 °, indicating a good drop drop property, the contact angle after the acid resistance test was 86 °, the drop angle was 14 °, and the contact angle after the light resistance test was 84 °. The falling angle was 15 °, maintaining high water repellency.
[0053]
Comparative Example 1
In the above-mentioned “Example 1 (1) Preparation of mixed solution of fluoroalkylsilane having hydrolyzable groups at both ends and alkoxy-terminated dimethylsilicone”, instead of FAS containing hydrolyzable groups at both ends, water is added only at one end. Coating solution with the concentration described in Example 1 except that dodecafluorooctyltrichlorosilane having a decomposable group [CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ SiCl ₃ : C6FASC] was used to prepare mixed solution X Was prepared.
As a result, a homogeneous and transparent film was not obtained.
[0054]
Comparative Example 2
In the above-mentioned “Example 1 (1) Preparation of mixed solution of fluoroalkylsilane having hydrolyzable groups at both ends and alkoxy-terminated dimethylsilicone”, instead of FAS containing hydrolyzable groups at both ends, water is added only at one end. Coating was carried out at the concentration described in Example 2 except that mixed solution X was prepared using dodecafluorooctyltrichlorosilane having a decomposable group [CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ SiCl ₃ : C6FASC]. A liquid was prepared.
As a result, the resulting highly water-slidable coating film showed good water droplet tumbling properties with an initial contact angle of 106 ° and an initial tumbling angle of 8 °, but the contact angle after the acid resistance test was 54 ° and the tumbling angle was 30 °. As described above, the contact angle after the light resistance test was 57 °, and the sliding angle was 30 ° or more.
[0055]
【The invention's effect】
Since the high water-sliding film of the present invention has both high water repellency durability and excellent water slidability, for example, when used in a window glass for a vehicle, the front, side, and rear visibility during rainy weather It is easy to secure and improves the safety of driving, and further, such effects can be maintained over a long period of time.
[Brief description of the drawings]
FIG. 1 is a diagram showing a procedure for preparing a mixed solution X of a fluoroalkylsilane and an alkoxy-terminated dimethylsilicone in Example 1.
2 is a view showing a preparation procedure of silica sol Y in Example 1. FIG.
3 is a diagram showing a procedure for preparing a coating liquid in Example 1. FIG.

Claims (9)

A composition comprising an alkoxy-terminated dimethyl silicone represented by the general formula [1] and a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] as a water-sliding component in a silica matrix A highly water-sliding film characterized by being mixed.
Here, X is -OR or _{-R'Si (OR) r (CH 3} ) 3-r (R is a monovalent an alkyl group, R 'is an divalent alkylene group) alkoxy group or an alkoxy group represented by The containing group, p, q, and r are integers of 1 to 3, and n is an integer of 2000 or less.
Here, s is an integer of 1 to 12, t and u are integers of 1 to 3, and Z is a hydrolyzable group. The highly water-slidable coating film according to claim 1, wherein the number of alkoxy groups of the alkoxy-terminated dimethyl silicone represented by the general formula [1] is 3 or more. The highly water-slidable coating film according to claim 1, wherein the number of hydrolyzable groups of the fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] is 3 or more. The alkoxy-terminated dimethyl silicone represented by the general formula [1] is present in an amount of 1 to 300% by weight based on silica obtained from alkoxysilane. The highly water-slidable coating according to crab. The fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2] is in the range of 10 to 3000 mol% with respect to the alkoxy-terminated dimethylsilicone represented by the general formula [1]. The highly water-slidable coating film according to any one of claims 1 to 4, which is present. In the silica matrix, a component formed by bonding an alkoxy-terminated dimethyl silicone represented by the general formula [1] and a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2], The high water-sliding film according to any one of claims 1 to 5, which is dispersed. The high water-sliding film according to any one of claims 1 to 6, wherein the high water-sliding film is formed on a base layer made of a metal oxide formed on the surface of the substrate. The method for coating a highly water- slidable coating film according to any one of claims 1 to 7, wherein the coating method is performed by the following steps.
(1) preparing a silica sol as a matrix component by hydrolyzing and polycondensing alkoxysilane;
(2) An alkoxy-terminated dimethyl silicone represented by the general formula [1], a fluoroalkylsilane having hydrolyzable groups at both ends represented by the general formula [2], and the above (1) A step of preparing a coating solution by mixing silica sol,
(3) A step of applying a heat treatment after applying the coating solution on the surface of the substrate. The method for coating a highly water-slidable coating according to claim 8, wherein the heat treatment is performed at a temperature of 600 ° C or lower.