JP2002263571A - Composite coat having good water slipping property and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composite coat having good water slipping properties which is excellent in water repellent durability and water slipping properties (water droplet slipping-down properties). SOLUTION: The surface of a base material is coated with the composite coat in which a silanol-terminal silicone is dispersed in a silica matrix as a water slipping component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to, in particular,
The present invention relates to a composite highly water-slidable coating having extremely excellent water-sliding property (water-dropping property) and a method for producing the same, which can be used for vehicle window glasses, mirrors, and other industrial window glasses.

[0002]

2. Description of the Related Art Water-repellent glass in which a fluoroalkyl group-containing silane compound is treated on the surface of a substrate is used as a water-repellent window for automobiles because raindrops (water droplets) on the surface are spherical and exhibit strong water repellency. Is spreading. However, fluoroalkyl group-containing silane-based water-repellent glass has a strong interaction with water droplets, and therefore has a low water-drop sliding property. The amount of water required for the water droplet to slide down at a glass inclination angle of 30 ° is 40 to 50 μl. Relatively large. For this reason, many raindrops are likely to remain on the window during rainy weather, which may lower the driver's driving visibility, and a water-repellent glass having more excellent waterdrop sliding properties is desired.

As an attempt to improve the water drop sliding property, a composition containing a silicone wax, an organopolysiloxane, a surfactant and the like has been proposed.
Japanese Patent Publication No. 50-15473 discloses a composition comprising an alkylpolysiloxane and an acid.
No. 2 discloses a composition containing an amino-modified silicone oil and a surfactant, which can be obtained with a water droplet amount of about 15 μl at an inclination of 30 °. Also, JP-A-11-181412 discloses that
_{- (CH 2) 3 (CF} 2) 7 CH 3 , etc. units groups are bonded directly to the silicon atoms forming the organosiloxane units, and - (CH ₂₎ groups, such as ₃ SiCl ₃ to form an organosiloxane units A surface treatment agent characterized by containing a fluorine-containing silicone compound having a unit directly bonded to a silicon atom and / or a partial hydrolysis product of the compound is disclosed. (The amount of water required for the water drop to slide down at 30 ° is equivalent to about 20 μl). In these disclosures, a water-lubricating agent component is directly treated on a substrate to form a water-lubricating layer, and the transparent coating obtained by hybridizing the water-lubricating agent component and the matrix component of the present invention is used as a substrate. It is different from what is formed on top.

Japanese Patent Application Laid-Open No. Hei 8-12375 discloses a method for forming a transparent film composed of a water-sliding agent component and a matrix component on a substrate, a fluoroalkyl group-containing silane compound, polydimethylsiloxane and / or polydimethylsiloxane. Alternatively, a solution obtained by hydrolyzing a mixture of derivatives thereof in a solvent and a solution obtained by hydrolyzing an alkoxysilane compound in a solvent are mixed, and the mixed solution is applied to a substrate surface. Discloses a water-repellent article in which a fluoroalkyl group and a methyl group formed by the above method are present in a higher concentration in the outer surface layer than in the inner layer of the coating film. Further, JP-A-2000-26758 discloses, as a coating composition capable of forming a water-slidable film, a hydroxyl-containing vinyl polymer,
Contains at least one crosslinking agent component selected from an epoxy-terminated siloxane polymer, a sulfonic acid compound, a polyisocyanate compound which may be blocked, and a melamine resin, and a surfactant selected from a specific dialkyl sulfosuccinate and an alkylene oxide silane. It is disclosed that a coating composition capable of forming a water-slidable coating film exhibits extremely excellent performance (same level as the present invention) with a falling angle of 5 # or less at a water droplet amount of 10 μl.

[0005]

However, the water-repellent article described in the above-mentioned Japanese Patent Application Laid-Open No. 8-123375 has a water drop sliding property of a level at which a water drop of 50 μl slides down at an inclination of about 16 °. In the case of aiming for good raindrop removal, the level is not sufficient. Further, the water-repellent article described in JP-A-2000-26758 has low transparency and is limited to use as a coating material.

[0006]

DISCLOSURE OF THE INVENTION In view of the above problems, the present inventors have studied how to effectively disperse a water-sliding component in a silica matrix, As a result of intensive research on how strongly the water-sliding component is held and high durability is obtained, silica sol as a matrix-forming component obtained by hydrolysis and polycondensation of alkoxysilane and the above-mentioned [ 1] It has been found that the problem can be solved by combining with a specific silanol-terminated silicone represented by the formula.

That is, the composite highly water-smooth coating of the present invention comprises:
It is characterized in that a substrate surface is coated with a composite high water-sliding film in which a silanol-terminated silicone as a water-sliding component represented by the general formula [1] is dispersed in a silica matrix.

[0008]

Embedded image

[0009] Here, wherein R1 is -CH ₃ or -C ₂ H
_5, R2 is or -C ₆ H ₅ same or as R1, m,
n is an integer, and m + n is 10 to 200.

Further, the composite highly water-slidable coating of the present invention is such that (m + n) in the general formula [1] is in the range of 10 to 200 and the n / (m + n) ratio is in the range of 0 to 0.4. In this case, m is an integer ranging from 6 to 200, and n is an integer ranging from 0 to 80. As for m, the average degree of polymerization of silicone increases as it increases, and in the case of 200 or more, the solubility of silicone in silica sol is remarkably reduced, and a homogeneous mixed sol cannot be obtained. Can not be obtained. On the other hand, when m is 6 or less, excellent water-sliding property cannot be obtained, which is not preferable. As for n, as the amount of n increases, the amount of phenyl groups introduced into the main chain increases, and the thermal stability increases, but the refractive index of silicone increases, and the solubility of silicone in silica sol decreases. For this reason, it is difficult to obtain a good-quality water-slidable film, which is not practically preferable. As a preferable range of n, the n / (m + n) ratio is 0 to 0.4 as described above. The copolymer represented by the general formula [1] may be in a random polymerization form or a block polymerization form. The average degree of polymerization (m + n) is important.

Further, according to the method for producing a composite highly water-slidable film of the present invention, a silica sol obtained by hydrolysis and polycondensation of a silanol-terminated silicone represented by the general formula [1] and an alkoxysilane on a substrate surface. Characterized by being coated with a mixed sol.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As the silanol-terminated silicone used in the present invention, a silanol-terminated silicone represented by the following general formula [1] can be used.

[0013]

Embedded image

[0014] Here, wherein R1 is -CH ₃ or -C ₂ H
_5, R2 is or -C ₆ H ₅ same or as R1, m,
n is an integer, and m + n is 10 to 200.

It is important that the terminal group of the silicone is an —OH group. If the group is not an —OH group, the solubility in the silica sol is significantly reduced, and a homogeneous mixed sol cannot be obtained.
As a result, a good quality water-sliding film cannot be obtained, which is not preferable in practical use. The average degree of polymerization of silicone [(m +
n) number] is important to be in the range of 10 to 200. When the average degree of polymerization is 10 or less, excellent water-sliding property is not obtained. On the other hand, when the average degree of polymerization is 200 or more, the solubility in silica sol is not increased. Is significantly reduced, so that a homogeneous mixed sol cannot be obtained and a high-quality composite water-sliding film cannot be obtained, which is not preferable in practical use.

N / (m +) in the general formula [1], which is a ratio of a siloxane unit in which a —C ₆ H ₅ group is bonded to a silicon atom.
n) The ratio is preferably in the range of 0 to 0.4. This is due to the fact that the refractive index of silicone is almost equal to that of silica as a matrix, and it is easy to obtain an optically uniform coating. On the other hand, if this ratio exceeds 0.4, the refractive index of silicone increases, and the solubility of silicone in silica sol decreases. No.

[0017] The silica matrix of the composite highly water-slidable coating can be formed, for example, by a silica sol.
The silica sol can be obtained by hydrolysis and polycondensation of alkoxysilane.Examples of the alkoxysilane include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilanesilane; For example, trialkoxysilanes such as methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, and propyltriethoxysilane, or dialkoxysilanes can be used. Among the above alkoxysilanes, tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane, and trialkoxysilanes such as methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane and ethyltriethoxysilane are preferable.

The coating of the coating solution comprising the mixed sol of the silanol-terminated silicone represented by the general formula [1] and the silica sol on the surface of the substrate can be carried out, for example, by the following method.

The silica sol can be prepared, for example, by advancing hydrolysis and polycondensation of alkoxysilane as shown in FIG. First, an alkoxysilane (for example, tetraethoxysilane [Si (O
A predetermined amount of C ₂ H ₅ ) ₄ : TEOS]) and a solvent are mixed and stirred (for example, for about 30 minutes) to obtain a solution A. As the solvent, lower alcohols such as ethanol and isopropyl alcohol and mixtures thereof are desirable, but ethers and ketones can also be used. On the other hand, the acid aqueous solution and the solvent are mixed and stirred (for example, for about 30 minutes) to obtain a solution B. Next, after mixing the solution A and the solution B, the mixture is stirred at room temperature for a long time (for example, about 15 hours) to proceed the hydrolysis and polycondensation reaction of the alkoxysilane to obtain a silica sol. As described above, the hydrolysis of the alkoxysilane can be performed by using the alkoxysilane as a starting material, adding a small amount of water and an acid catalyst such as hydrochloric acid, nitric acid, and acetic acid, and drying and heating the hydrolyzate. To obtain a silica sol.

Next, the preparation of the coating liquid is performed, for example, by
This can be performed by a method as shown in FIG. Silanol terminated silicone (for example, dimethyl silicone having both ends -OH [N24SOL (OH); manufactured by Gelest, DM
S-S15] and a solvent (for example, methyl ethyl ketone) are mixed and stirred (for example, for about 5 minutes). Next, the silica sol prepared above is added thereto, and stirred for a long time (for example, about 15 hours) at room temperature to obtain a coating liquid.

Next, the surface of the substrate is coated with the coating solution for a composite highly water-slidable film obtained above. Coating methods include hand coating, nozzle flow coating, dipping,
Spraying method, reverse coating method, flexo method, printing method,
Various coating methods such as a known coating method such as a flow coating method or a spin coating method, and a combination thereof can be appropriately employed. It can also be used as a simple type of spray-type water-repellent agent.

Next, after applying the coating solution for the composite high water-sliding film, the coating solution may be air-dried after application of the coating solution, or may be dried naturally or simultaneously with the drying process at a temperature exceeding room temperature and 300 ° C. or less. The heat treatment can also be performed at the above temperature.

The substrate is not particularly limited, such as glass and plastic. For example, in the case of a glass substrate, float glass or glass commonly used for architectural window glass, automobile window glass, or the like is used. Inorganic transparent plate glass such as glass produced by a roll-out method is preferred, and those not particularly limited to colorless or colored, and the type or color tone, combination with other functional films, the shape of the glass, and the like. Not only, but also various tempered glass and strengthened glass as well as bent sheet glass,
It can be used as a flat plate or a single plate, and can also be used as a double glazing or a laminated glass. The coating may be formed on both surfaces of the glass substrate.

[0024] The surface of the substrate to which the lubricity is applied may be provided with a base layer made of a metal oxide. For example, in the case of a glass substrate, the underlayer is preferably an oxide thin film containing a metal oxide such as silicon oxide as a main component, and the surface treatment agent is applied thereon to coat the highly water-smooth coating. Thereby, highly durable glass having high durability can be obtained.

The composite highly water-slidable film of the present invention is a hybrid comprising a silanol-terminated silicone as a water-slidant component and a silica sol as a matrix, and
Since the dispersibility of the water-sliding agent component and the silica matrix is high, it is possible to fix the water-sliding agent that exhibits high water-sliding property in the vitreous silica matrix having high mechanical strength,
It is possible to form a coating film having both high slipperiness and durability.

The water-sliding property in the present invention is defined as a method described in the evaluation method of the examples described below, for example, a condition in which the composite high-sliding film-forming substrate obtained above is inclined at 30 °. Then, pure water is slowly dropped on the sample surface with a microsyringe. At this time, the amount (volume) of the water droplet at the time when the water droplet starts to move is defined as the slipperiness (water droplet falling property),
This is indicated by “μl”. The high water-sliding property of the present invention means that the water-sliding property obtained by the above method is 10 µl or less, more preferably 5 µl or less.

[0027]

Embodiments of the present invention will be described below. Note that the present invention is not limited to these examples. In addition, the evaluation method of a water-slidable film is shown below.

[Evaluation of Water-Sliding Film] A method for evaluating a water-sliding film is described below. 1) Initial contact angle The angle between a water droplet and the sample surface when about 2 μl of pure water was placed on the sample surface of the highly water-slip coating was measured with a contact angle meter. In addition, it measured in air | atmosphere (about 25 degreeC) using Kyowa Interface Science CA-X type as a contact angle meter. 2) Water slippage While the sample was inclined at 30 °, pure water was slowly dropped on the sample surface with a microsyringe, and the amount (volume) of the waterdrop at the time when the waterdrop moved at a speed of 2 cm / sec was determined as a waterdrop ( μl). In addition, as for the slipperiness, 10 μl or less was regarded as acceptable. 3) Falling angle While holding the sample horizontally, 5
After dropping 0 μl of pure water, the sample was gradually inclined, and the inclination angle at which the water droplet started to move was defined as the falling angle (°). The falling angle was measured in the atmosphere (about 25 ° C.) using a CA-A type manufactured by Kyowa Interface Science.

Example 1 (1) Preparation of silica sol The silica sol was tetraethoxysilane [Si (OC ₂ H ₅ )
₄ : TEOS] by hydrolysis and polycondensation. FIG. 3 shows a silica sol preparation procedure and a mixing ratio (weight ratio) of each component. First, tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ : TEOS]; 312.5 g
And Echinene F1 (a mixture of lower alcohols consisting of 90% by weight of ethanol and 10% by weight of isopropyl alcohol); 450.0 g, and stirred for about 30 minutes to obtain solution A.
I got 0.1 mol / l nitric acid aqueous solution; 7.5
g, H ₂ O; 210.0 g and echinene F1; 20.0 g
g was mixed and stirred for about 30 minutes to obtain a solution B. Then
After mixing Solution A and Solution B, the mixture was stirred at room temperature for about 15 hours to obtain a silica sol.

(2) Preparation of Coating Solution As shown in FIG. 4, the preparation procedure and the mixing ratio (weight ratio) of each component, dimethyl silicone having an average degree of polymerization of 24 (average molecular weight: 1750) and both terminals being --OH. [N24SOL (O
H); manufactured by Gelest, DMS-S15]; 0.22 g and methyl ethyl ketone; 7.00 g were mixed and stirred for about 5 minutes. Next, the silica sol prepared in the above (1);
2.00 g was added therein, and the coating solution was obtained by stirring at room temperature for about 15 hours.

(3) Washing of Glass Substrate The surface of a float glass having a size of 100 mm × 100 mm × 2 mmt was polished with a polishing liquid, and washed and dried with a glass washer (manufactured by our company). The polishing liquid used here was a suspension in which about 1% of a glass polishing agent MIRAKE E (manufactured by Mitsui Kinzoku Kogyo) was mixed with water.

(4) Preparation of Composite High Water-Sliding Film The coating liquid obtained in the above (2) was applied on the glass substrate by spin coating. First, the washed glass substrate was placed on a spin coater, and the rotation speed was 50
While rotating at a speed of 0 rpm, about 1.0 to 1.5 ml of the coating liquid obtained in (2) is dropped, and the coating is dried at a rotating speed of 30 seconds to obtain a good transparent gel film. Was. Next, heat treatment was performed at 300 ° C. for 10 minutes to obtain a glass substrate coated with the composite highly water-slidable film.

Next, the performance of the obtained composite highly water-slidable coated substrate was evaluated in the manner described in the above [Evaluation of water-slidable coating]. As a result, as shown in Table 1, the contact angle was 104 °,
The slipperiness was 4 μl, and the falling angle was 1 °, indicating extremely high water repellency and slipperiness.

[0034]

[Table 1]

Example 2 As a starting material, the average degree of polymerization was 56 (average molecular weight: 420).
0), dimethyl silicone having both ends -OH [N56S
OL (OH); manufactured by Gelest, DMS-S21], except that the procedure was the same as in Example 1. As a result of the evaluation, the contact angle was 105 °, the slipperiness was 4 μl, and the falling angle was 1 °.
And showed very high water repellency and water slip.

Example 3 As a starting material, the average degree of polymerization was 70 (average molecular weight: 520).
0), dimethyl silicone having both ends -OH [N70S
OL (OH); manufactured by Toshiba Silicone Co., Ltd., YF3800], except that the procedure was the same as in Example 1. As a result of the evaluation, the contact angle was 104 °, the slipperiness was 5 μl, and the falling angle was 1 °.
And showed very high water repellency and water slip.

Example 4 As starting materials, a diphenylsiloxane unit in which two --C ₆ H ₅ groups are bonded to a silicon atom and two --C atoms are bonded to a silicon atom
It consists of a dimethylsiloxane unit to which an H ₃ group is bonded, has an average degree of polymerization of 10 (average molecular weight: 1000), and has both ends at −
OH, diphenyldimethylsilicone having an average of 16 mol% of diphenylsiloxane units [Ph-SOL
(OH); except that PDS-1615 manufactured by Gelest was used. As a result of the evaluation, the contact angle was 97 °, the slipperiness was 7 μl, and the falling angle was 2 °, indicating extremely high water repellency and slipperiness.

Comparative Example 1 As a starting material, the average degree of polymerization was 7 (average molecular weight: 55
0), dimethyl silicone having both ends -OH [N7SO
L (OH); manufactured by Gelest, DMS-S12], except that all were the same as in Example 1. As a result of the evaluation,
The contact angle was 103 °, indicating high water repellency.
Rejection was 7 μl, and the falling angle was as low as 5 °.

Comparative Example 2 As a starting material, the average degree of polymerization was 243 (average molecular weight: 18
000), dimethyl silicone [N2
43SOL (OH); Gelest, DMS-S27]
All were the same as Example 1 except that was used. As a result of evaluation, since the solubility of the silicone in the silica sol was low, film unevenness occurred and a good appearance was not obtained.
The contact angle was 104 °, indicating high water repellency.

COMPARATIVE EXAMPLE 3 0.5 ml of a solution in which 10.00 g of ethyl acetate was mixed with 1.00 g of dimethyl silicone [N24SOL (OH)] having an average degree of polymerization of 24 (average molecular weight: 1750) and both ends of --OH was mixed. The solution was dropped on a glass substrate, sufficiently stretched over the entire surface of the glass with a cotton cloth (trade name: Bencott), and air-dried for about 5 minutes. After that, heat treatment was performed at 80 ° C. for 10 minutes in a muffle furnace, and excess silicone remaining cloudy was removed by iP.
The sample was wiped with A to obtain a transparent sample. As a result of the evaluation,
The contact angle was 98 °, indicating high water repellency.
It was rejected as μl and the falling angle was as low as 6 °.

Comparative Example 4 Dimethyl silicone [N56SOL (OH)] having an average degree of polymerization of 56 (average molecular weight: 4200) and both terminals being --OH
All were the same as Comparative Example 3 except that was used. As a result of the evaluation, the contact angle was 98 °, indicating high water repellency. However, the slipperiness was 12 μl, which was unacceptable, and the falling angle was 4 °, which was a slightly low level.

Comparative Example 5 Dimethyl silicone [N70SOL (OH)] having an average degree of polymerization of 70 (average molecular weight: 5200) and both terminals being --OH.
Was the same as Comparative Example 3 except that was dissolved. As a result of the evaluation, the contact angle showed high water repellency of 96 °,
The slipperiness was rejected as 14 μl and the falling angle was 5
° and low level.

[0043]

The composite highly water-slidable coating of the present invention comprises a hybrid comprising a silanol-terminated silicone as a water-slippery component and a silica sol as a matrix, and has a high binding property between the water-slippery component and a silica matrix. Since the water-sliding agent that exhibits high water-sliding property is dispersed in a vitreous silica matrix having high mechanical strength, high water-sliding property (10 μl or less at 30 ° inclination), excellent water repellency, and good practical durability When used for a window glass for a vehicle, it is particularly effective.

[Brief description of the drawings]

FIG. 1 is a diagram showing a procedure for preparing a silica sol.

FIG. 2 is a diagram showing a procedure for preparing a coating liquid.

FIG. 3 is a view showing a procedure for preparing a silica sol in Example 1.

FIG. 4 is a diagram showing a procedure for preparing a coating liquid in Example 1.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 183/04 C09D 183/04 C09K 3/18 104 C09K 3/18 104 (72) Inventor Hiroaki Arai Mie 1510 Oguchi-cho, Matsusaka-shi Central Glass Co., Ltd., Glass Research Laboratories (72) Inventor Shigeo Hamaguchi 1510 Oguchi-cho, Matsusaka-shi, Mie Central Glass Co., Ltd. Glass Research Laboratories F-term (reference) 4D075 CA09 CA31 CA34 CA36 CB06 DA06 DB13 DB31 DC01 DC13 DC38 EA12 EB43 EB56 4F100 AG00A AK01A AK52B AT00A BA02 EH46 GB07 GB32 JB06 JM01B YY00B 4G059 AA01 AC30 FA22 FA29 FB06 4H020 BA32 4J038 DL021 DL031 DL032 GA03 JC33 KA09 MA06 P18 PA19 PC03 P08

Claims (3)

[Claims] 1. A composite high water-sliding film in which a silanol-terminated silicone as a water-sliding component represented by the general formula [1] is dispersed in a silica matrix on a substrate surface. Composite high water-slip coating. Embedded image Here, wherein R1 is -CH ₃ or -C ₂ H _5, R2 is R
1 and the same or a -C ₆ H _5, m, n are integers, m + n is 10 to 200. 2. The method of claim 1, wherein n / (m + n) in said general formula [1].
The ratio is in the range of 0 to 0.4.
The composite highly water-smooth coating according to the above. 3. A base material surface coated with a mixed sol of a silanol-terminated silicone represented by the general formula [1] and a silica sol obtained by hydrolysis and polycondensation of alkoxysilane. A method for producing a composite high water-slidable coating.