KR20140022491A

KR20140022491A - Superhydrophobic coating solution composition and method for producing the coating composition

Info

Publication number: KR20140022491A
Application number: KR1020120088146A
Authority: KR
Inventors: 박상권
Original assignee: 동국대학교 산학협력단
Priority date: 2012-08-13
Filing date: 2012-08-13
Publication date: 2014-02-25
Also published as: KR101401754B1; WO2014027825A1

Abstract

The present invention relates to a super hydrophobic coating solution composition capable of being applied to a window and a method for producing the coating composition. The coating composition of the present invention can be applied to a window for a building and a vehicle since the composition has improved transparency and enables the implementation of self-cleaning. The coating composition can contribute to the development of a green environment by the implementation of self-cleaning when being applied to the exterior and interior materials of glass and ceramic building material as well as a window for a building and contributes to the reduction of carbon dioxide emission.

Description

TECHNICAL FIELD [0001] The present invention relates to a superhydrophobic coating solution composition and a method for producing the same,

The present invention relates to a coating solution composition that can be applied to windows and a method for producing a coating composition.

Typical fabrics, paints, and composite membranes create high added value by adding various functionalities to the materials used to increase their use. As an example of such functionalities, there is a super-water-repellent function, and the super-water-repellent function is derived from the 'soft petal effect'.

The soft petal effect is the effect of keeping the insect wings such as leaves, butterflies, etc., such as soft petals, rice, etc., always clean, due to their self-cleaning ability. Professor Wilhelm Basroth, a botanist at the University of Bonn in Germany in 1975, observed a petal leaf with a microscope at high magnification, and found that the surface had micrometer protrusions (μm) (1 millionths of a meter) , And then confirmed that the surface of the protrusions had nanometers (1 / billionth of a meter) of cilia on their surface. Because of the surface structure, the petal leaf is rolled down without water droplets, so it has self-cleaning ability that the pollutant is washed down automatically.

This technology is called wetting and surface modification technology. It is a field of surface modification of the solid surface physically and chemically. It is a technology to make the contact angle to be 150 ° or more when liquid comes into contact with the surface of solid. It is necessary to identify the phenomenon already occurring in the natural world and to make physicochemical fabrication of super water-repellent surface for easy industrial use, Application technology.

Such a superhydrophobic property is known to be realized by the microstructure existing on the surface and the low energy material covering the surface (wax in the case of a lotus leaf). A smooth surface having no microstructure is a material having a low energy, such as organic matter or polymer (fluorine or silicone resin) The maximum contact angle is about 120 °, which is the limit. The water droplets with high surface tension have very high contact angles due to the very limited contact area with the protrusions on the super-water-repellent surface with low surface energy. As a result, the water droplets are rolled down with the contaminants adhering to the water droplets and self- . Recently, a super-water-repellent coating has been applied to some products such as paints by coating a polymer resin having a low surface energy with a specific microstructure on a substrate. However, such a super-water-repellent coating has a problem in that the transparency Therefore, it can not be applied to various window products requiring high transparency.

Korean Laid-Open Publication No. 10-2010-0125905

Accordingly, the present inventor has developed a highly transparent self-cleaning functional coating material which can be used for architectural and automobile windows, and further applicable to protective glass for solar cells and outermost glass for outdoor displays.

The present invention is to provide a coating solution composition and a method for preparing the coating composition to maximize transparency and super water repellency.

The present invention relates to a coating solution composition comprising a silica precursor, a neutral catalyst, an alcohol and a non-fluorine silane-based organic material.

The present invention also provides a process for preparing a silica nanostructure comprising: (a) forming a silica nanostructure on a substrate using a silica precursor, a neutral catalyst, an alcohol and water; And (b) coating the silane-based organic material using the non-fluorine silane-based organic material after the step (a).

The coating composition of the present invention is excellent in transparency and can realize self-cleaning function, so that it is applicable to architectural use and automobile window use. When applied to building exterior and interior materials as well as architectural windows and glass and ceramics, it can contribute to the creation of a green environment by implementing the self-cleaning function and ultimately contribute to the reduction of carbon dioxide emissions.

1 is a cross-sectional view of a coating structure produced in the present invention.
2 is a contact angle, an SEM photograph, and an AFM image for Examples 1, 5, and 6.
3 is a light transmission chart for Example 8 and Comparative Example 2. Fig.
4 is a photograph (stain resistance and self-cleaning property) washed with water drops (1 ml) after application of carbon black (0.1 g) to (left) Comparative Example 2 (right) Example 8.
Figure 5 shows the contact angle results (25 < 0 > C) according to coating solution composition for Example 9, Graph.
6 is a graph of the contact angle with temperature for Example 10. Fig.

10 to 40 parts by weight of a silica precursor, 0.0001 to 0.02 parts by weight of a neutral catalyst, 35 to 88 parts by weight of an alcohol, and 0.13 to 2.6 parts by weight of a non-fluorine silane-based organic material with respect to 100 parts by weight of the total coating solution composition. In the case where it is included in the above weight ratio, the substrate is subjected to a sol-gel reaction with the coating solution composition of the present invention and treated with a non-fluorine silane-based organic material to obtain a coating composition having high transparency and super water repellency.

The silica precursor may include, but is not limited to, a silicon alkoxide based, and more specifically, a tetramethyl orthosilicate, a tetraethyl orthosilicate (TEOS), a tetrapropoxy silane, And may be tetraisopropoxy silane.

The neutral catalyst may be, but is not limited to, ammonium fluoride (NH ₄ F).

Examples of the non-fluorine silane-based organic material include, but are not limited to, chlorotrialkyl silane-based organic materials such as chlorotrimethyl silane, alkyltrichlorosilane such as octadecyltrichlorosilane, ) Based organic materials.

The alcohol may be, but is not limited to, methanol, ethanol or isopropanol.

The present invention also relates to a process for preparing a coating composition. (A) forming a silica nanostructure on a substrate using a silica precursor, a neutral catalyst, an alcohol and water; And (b) coating the silane-based organic material using the non-fluorine silane-based organic material after the step (a).

In the step of forming the silica nanostructure on the substrate in the step (a), the substrate is not limited thereto, but it may be a glass substrate, and the impurities may be removed so that the nanostructure can be uniformly formed on the glass surface. In an embodiment of the present invention, hydrogen peroxide and a sulfuric acid solution are treated to remove impurities on the glass surface to remove organic substances adsorbed / attached to the glass surface.

Step (a) is a step of forming a silica nanostructure on a glass substrate by a sol-gel method in order to realize a super water repellent property while maintaining transparency, and more specifically, a silica precursor, water A transparent and uniform coating film can be obtained by preparing an alcohol solution in which a catalyst is dissolved and immersing the glass substrate in a solution to cause a sol-gel reaction (hydrolysis reaction and condensation reaction).

In this case, in order to form a silica nanostructure coating film, the reaction temperature may be 20 to 50 ° C or 25 ° C. When the reaction temperature is changed, the contact angle varies depending on the reaction time. The reaction time may be 1 to 50 hours and 25 hours.

The alcohol may be, but is not limited to, methanol, ethanol or isopropanol.

In the case of using the neutral catalyst according to the present invention, it is not necessary to neutralize the acidic catalyst or the basic catalyst when the catalyst is used, which simplifies the process.

The glass substrate on which the silica nanostructure coating film is formed can be taken out in a dip coater at a rate of 3 to 10 mm / min, and then dried.

In the step (b), the surface may be modified using a non-fluorine silane-based organic material on the surface of the glass substrate on which the silica nanostructure is formed. By modifying the surface, the water repellency can be further improved, and when a non-fluorine silane-based organic material is used among silane-based organic materials, transparency can be maximized.

More specifically, the glass substrate coated with the silica nanostructure can be immersed in a solvent in which the non-fluorine silane-based organic material is dissolved, and coated at 20 to 100 ° C, 50 ° C for 0.5 to 5 hours and 1 hour.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are intended to illustrate the contents of the present invention, but the scope of the present invention is not limited to the following examples. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

< Example 1>

1. Preparation of glass substrate

As the glass substrate, a 1 mm thick glass slide (Paul Marienfeld GmbH, Germany) was used. The glass was immersed in a mixture of hydrogen peroxide and sulfuric acid at a volume ratio of 1: 3 for at least 12 hours to remove impurities on the surface. The solution was washed with distilled water and dried at 105 ° C for 1 hour.

2. Preparation of coating solution

In order to form a silica nanostructure on the glass substrate, a silica precursor, tetraethyl orthosilicate (TEOS, reagent grade, Aldrich), water and ammonium fluoride (NH ₄ F, reagent grade, Aldrich) Aldrich) was used. The mixed coating solution was stirred at room temperature for about 30 minutes at a concentration of 22 parts by weight of TEOS, 12 parts by weight of water and 0.004 parts by weight of ammonium fluoride.

3. Glass On the substrate Formation and drying of nanostructures

The washed glass substrate was immersed vertically in the coating solution and allowed to react at 25 ° C for 25 hours so that a silica nanostructure could be formed on the surface of the glass substrate by a sol-gel reaction. At this time, when the reaction temperature is changed, the contact angle varies depending on the reaction time. Subsequently, the glass substrate coated with nanostructures was taken out at a rate of 5 mm / min with a dip coater, dried at room temperature and further dried at 80 ° C.

4. Silane system Organic coating

The glass substrate coated with the silica nanostructure was immersed in hexane solution in which trimethylchlorosilane ((CH ₃ ) ₃ SiCl) was dissolved in 0.01 part by weight, reacted at 50 ° C for 1 hour and cured at 125 ° C for 1 hour, Based organic coating was completed.

< Example 2>

The coating was prepared in the same manner as in Example 1 except that the coating solution composition of step 2) was 19 parts by weight of TEOS, 10 parts by weight of water and 0.003 part by weight of ammonium fluoride.

< Example 3>

Proceed in the same manner as in Example 1 except that 0.8 part by weight of hydrogen chloride (HCl) was used instead of ammonium fluoride (NH ₄ F) as the catalyst of step 2).

< Example 4>

Proceed in the same manner as in Example 1 except that ammonium hydroxide (NH4OH) at a concentration of 0.7 part by weight was used as a catalyst in step 2) instead of ammonium fluoride (NH4F).

< Example 5>

The procedure of Example 1 was followed except that the coating time of step 3) was 10 hours.

< Example 6>

The procedure of Example 1 was followed except that the coating time of step 3) was 48 hours.

< Example 7>

(Trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane), which is a fluorine silane-based organic material, instead of trimethylchlorosilane in Step 4) Respectively.

< Example 8>

Proceeding in the same manner as in Example 1, a low iron glass (4 mm in thickness, HANGLAS) was used instead of a glass slide as a glass substrate in step 1).

< Example 9>

The procedure of Example 1 was followed, except that the coating solution of step 2) was used in various compositions as follows (see FIG. 5).

A; 26 parts by weight of TEOS, 14 parts by weight of water, 0.005 part by weight of ammonium fluoride

B; 23 parts by weight of TEOS, 16 parts by weight of water, 0.004 part by weight of ammonium fluoride

C; 23 parts by weight of TEOS, 14 parts by weight of water, 0.004 part by weight of ammonium fluoride

D; 22 parts by weight of TEOS, 12 parts by weight of water, 0.004 part by weight of ammonium fluoride

E; 19 parts by weight of TEOS, 10 parts by weight of water, 0.003 parts by weight of ammonium fluoride

< Example 10>

The procedure of Example 1 was followed except that the temperature of step 2) was kept at 40 캜, 45 캜 or 50 캜 (see Fig. 6).

< Comparative Example 1>

A glass slide glass substrate having only the step 1) in Example 1 was used.

< Comparative Example 2>

A low iron glass substrate having only the step 1) in Example 8 was used.

1. Characterization

(1) contact angle

In order to confirm the water repellency of the coating formed on the glass substrate, the contact angle was measured with a contact angle meter (KRUSS, DSA100), and the results for all Examples are summarized in Table 1 and the results for Examples 1, 5 and 6 Is shown in FIG. 2 as a photograph.

(2) Electron microscope (SEM)

In order to confirm the nanostructure of the coating formed on the glass substrate, it was observed with an electron microscope (SEM, HITACHI, S-3000N), and SEM photographs of Examples 1, 5 and 6 are shown in Fig.

(3) Atomic Force Microscope (AFM)

In order to confirm the nanostructure of the coating formed on the glass substrate, it was observed with an atomic force microscope (AFM, Veeco Co., Nanoman II), and the AFM images of Examples 1, 5 and 6 are shown in Fig.

(4) Light transmittance

The light transmittance of the coating formed on the glass substrate was measured using a UV-Vis spectrometer (Perkin Elmer, Lambda 35), and the light transmittance of Example 8 and Comparative Example 2 is shown in FIG.

(5) Comparison of Examples 1 to 10 and Comparative Examples 1 and 2

The contact angles and light transmittance results of Examples 1 to 10 and Comparative Examples 1 and 2 were compared in the following Table 1.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example
9 Example
10 Needs 143 115 135 142 53 93 154 130 5
Reference 6
Reference Excellent penetration ^a Excellent ^a Extremely
Bad ^b Bad ^c Excellent ^a Excellent ^a Extremely
Bad ^b Excellent ^d Good
Or excellent ^a Good
Or excellent ^a

a; Excellent = Higher light transmittance than 'Comparative Example 1'

b; Very poor = very low light transmittance compared to 'Comparative Example 1'

c; Bad = Low light transmittance compared to 'Comparative Example 1'

d; Excellent = Higher light transmittance than 'Comparative Example 2'.

1: glass substrate 2: silica nanostructure 3: silane-based organic material

Claims

A coating solution composition comprising a silica precursor, a neutral catalyst, an alcohol, and a non-fluorine silane-based organic material.

The method according to claim 1, wherein the total amount of the coating solution composition is 10 to 40 parts by weight of silica precursor, 0.0001 to 0.02 parts by weight of neutral catalyst, 35 to 88 parts by weight of alcohol, 0.13 to 2.6 parts by weight of non-fluorine silane-based organic material. Coating solution composition.

The method of claim 1, wherein the silica precursor is tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), tetrapropoxy silane or tetraisopropoxy silane (tetraisopropoxy silane). Coating solution composition, characterized in that.

The coating solution composition of claim 1, wherein the neutral catalyst is ammonium fluoride (NH ₄ F).

The coating solution composition of claim 1, wherein the non-fluorine silane-based organic material is chlorotrimethyl silane or octadecyltrichloro silane.

The coating solution composition of claim 1, wherein the alcohol is methanol, ethanol or isopropanol.

(a) forming a silica nanostructure on the substrate using a silica precursor, a neutral catalyst, alcohol and water; And
(b) after the step (a), coating with a non-fluorine silane-based organic material;
Method of producing a coating composition comprising a.

The method of claim 7, wherein the silica precursor is tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), tetrapropoxy silane or tetraisopropoxy silane (tetraisopropoxy silane) Method for producing a coating composition characterized in that.

The method of claim 7, wherein the neutral catalyst is ammonium fluoride (NH ₄ F).

According to claim 7, wherein the step of forming the silica nanostructures of step (a) is a method for producing a coating composition, characterized in that for 20 to 50 ℃, 1 to 50 hours.

The method of claim 7, wherein the coating of the silane-based organic material of step (b) is 20 to 100 ° C. for 0.5 to 5 hours.

The method of claim 7, wherein the non-fluorine silane-based organic material is chlorotrimethyl silane or octadecyltrichloro silane.