WO2014027825A1 - Super water-repellent coating solution composition, and method for preparing coating composition - Google Patents

Abstract

The present invention relates to a highly transparent and super water-repellent coating solution composition that can be applied to a window, and to a method for preparing the coating composition. Since the coating composition of the present invention has excellent transparency and can implement a self-cleaning function, the present invention can be applied to windows for construction purposes and automobiles. In the event the present invention is applied to exterior and glass and ceramic interior construction materials, as well as to windows for construction purposes, the present invention can contribute to a green environment by implementing a self-cleaning function, and ultimately can play a significant role in the reduction of carbon dioxide emissions as well.

Description

Super water-repellent coating solution composition and preparation method of coating composition

The present invention relates to a coating solution composition and a method for preparing the coating composition that can be applied to the window.

General fabrics, paints, composite membranes, etc. create a high value added by increasing the effectiveness of the use by giving various functionalities to the material used. An example of such a function is a super water-repellent function, such a super water-repellent function is derived from the 'lotus leaf effect'.

The lotus leaf effect is an effect that keeps the insect wings such as leaves and butterflies of plants, such as lotus leaf and rice, at all times by self-cleaning ability. The secret of the lotus leaf effect is that in 1975, Professor Wilhelm Barthlot, a botanist at the University of Bonn, Germany, observed the lotus leaf under a high-magnification microscope, indicating that micrometer-sized protrusions were formed on the surface. They then found cilia of nanometer size (nm: 1 billionth of a meter) on the surface of the projections. Because of this surface structure, the lotus leaf rolls down without attaching water droplets, and thus has a self-cleaning ability to automatically wash down pollutants.

Products applying the above-mentioned lotus leaf effect in real life also appear one after another, which is also called super water repellent surface technology, which is a field of wet and surface modification technology, by physically chemically modifying the surface of the solid surface When the liquid is in contact with the surface of the solid, the contact angle is 150 ° or more, the physical phenomenon of the super water-repellent surface for the identification of the phenomena already occurring in the natural world for easy industrial use, analysis of the wet phenomenon and Applied technology.

This super water repellency is known to be realized by the microstructure existing on the surface and the low-energy material (wax in the case of lotus leaf) covering the surface, and the smooth surface without the microstructure is a low energy organic material or polymer (fluorine-based or silicone-based resin). Even with coating, the maximum contact angle is limited to about 120 °. Water droplets with high surface tension show very high contact angles by contacting only very limited areas with the projections of superhydrophobic surfaces with low surface energy, resulting in self-cleaning functions as they drop with contaminants attached to water droplets. Will have Recently, superhydrophobic coating is applied to some products such as paints by coating a low surface energy polymer resin having a specific microstructure on a substrate, but such a superhydrophobic coating is opaque due to the resin itself or the microstructure. Therefore, it is not applicable to various window products requiring high transparency.

Accordingly, the present inventors have developed a highly transparent self-cleaning functional coating material which can be used in windows of construction and automobiles, and further applicable to solar cell protective glass or outdoor display outermost glass.

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.

In addition, the present invention comprises the steps of (a) forming a silica nanostructure on a substrate using a silica precursor, a neutral catalyst, alcohol and water; And (b) after the step (a), using a non-fluorine silane-based organic coating the silane-based organic; relates to a method for producing a coating composition comprising a.

The coating composition of the present invention is excellent in transparency and can implement the self-cleaning functionality, it can be applied to architectural and automotive windows. When applied to architectural exterior and interior materials of glass and ceramic as well as building windows, it can contribute to the creation of a green environment by realizing self-cleaning functionality, and ultimately contribute to the reduction of carbon dioxide emissions.

1 is a cross-sectional view of the 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 diagram for Example 8 and Comparative Example 2.

Figure 4 (left) Comparative Example 2 (right) The photograph (washing resistance and self-cleaning) of Example 8 washed with water droplets (1 ml) after application of carbon black (0.1 g).

5 is a contact angle results (25 ℃) according to the coating solution composition for Example 9 It is a graph.

6 is a graph of contact angle results according to temperature for Example 10. FIG.

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 total amount of the coating solution composition may include 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, and 0.13 to 2.6 parts by weight of non-fluorine silane-based organic material. When it is included in the weight ratio by the sol-gel reaction of the substrate with the coating solution composition of the present invention, by treating with a non-fluorine silane-based organic material it can be obtained a coating composition having high transparency and super water-repellent properties.

The silica precursor may be, but not limited to, silicon alkoxide-based, and more specifically, tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), tetrapropoxy silane, tetraisooxy It may be tetraisopropoxy silane.

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

The non-fluorine silane-based organic material is not limited thereto, but may be a chlorotrialkyl silane-based organic material such as chlorotrimethyl silane, or an alkyltrichloro silane such as octadecyltrichlorosilane. ) May be an organic material.

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

The invention also relates to a process for the preparation of the coating composition. More specifically (a) forming a silica nanostructure on the substrate using a silica precursor, a neutral catalyst, alcohol and water; And (b) after the step (a), using a non-fluorine silane-based organic coating the silane-based organic; relates to a method for producing a coating composition comprising a.

In the step of forming the silica nanostructure of the step (a) on the substrate, the substrate is not limited thereto, but may be a glass substrate, the impurities may be removed so that the nanostructure is uniformly generated on the glass surface. In one embodiment of the present invention to remove impurities on the glass surface by treating the hydrogen peroxide and sulfuric acid solution to remove the organic material adsorbed / adhered to the glass surface.

In addition, step (a) is to form a silica nanostructure on the glass substrate by a sol-gel (sol-gel) method in order to implement super water-repellent properties while maintaining high transparency, more specifically, 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 the solution to cause a sol-gel reaction (hydrolysis reaction and condensation reaction).

In this case, in order to form the silica nanostructure coating film, the reaction temperature may be 20 to 50 ° C and 25 ° C. When the reaction temperature is changed, the contact angle according to the reaction time is changed. In addition, the reaction time can be reacted for 1 to 50 hours, 25 hours.

The silica precursor may be, but not limited to, silicon alkoxide-based, and more specifically, tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), tetrapropoxy silane, tetraisooxy It may be tetraisopropoxy silane.

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

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

When using the neutral catalyst according to the present invention it is not necessary to go through the step of neutralizing when using an acidic catalyst or a basic catalyst it is possible to simplify the process.

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

In the step (b), the surface may be modified by 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 may be further improved, and the non-fluorine silane-based organic material among the silane-based organic materials may have an advantage of maximizing transparency.

The non-fluorine silane-based organic material is not limited thereto, but may be a chlorotrialkyl silane-based organic material such as chlorotrimethyl silane, or an alkyltrichloro silane such as octadecyltrichlorosilane. ) May be an organic material.

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

Hereinafter, examples will be described in detail to help understand the present invention. However, the following examples are merely to illustrate the content of the present invention is not limited to the scope of the present invention. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

<Example 1>

1. Preparation of Glass Substrate

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

2. Preparation of Coating Solution

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

3. Formation and drying of nanostructures on glass substrates

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

4. Silane Organic Coating

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

<Example 2>

Proceed in the same manner as in Example 1, the coating solution composition of step 2) was prepared by using a concentration of 19 parts by weight of TEOS, 10 parts by weight of water, and 0.003 parts by weight of ammonium fluoride.

<Example 3>

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

<Example 4>

Proceed in the same manner as in Example 1, but the catalyst of step 2) was used in the concentration of 0.7 parts by weight of ammonium hydroxide (NH4OH) instead of ammonium fluoride (NH4F).

Example 5

Proceed in the same manner as in Example 1, the coating time of step 3) was 10 hours.

<Example 6>

Proceed in the same manner as in Example 1, the coating time of step 3) was 48 hours.

<Example 7>

Proceed in the same manner as in Example 1, but instead of trimethylchlorosilane of step 4) a concentration of 0.007 parts by weight of trichloroperfluorooctylsilane (trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane) Used as.

<Example 8>

Proceed in the same manner as in Example 1, but a low iron glass (thickness 4mm, Diaman Co., Ltd.) commercial glass was used as the glass substrate of step 1) instead of the glass slide.

Example 9

Proceed in the same manner as in Example 1, 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 parts by weight of ammonium fluoride

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

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

D; 22 parts by weight of TEOS, 12 parts by weight of water, 0.004 parts 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>

Proceed in the same manner as in Example 1, but the temperature of step 2) was maintained at 40 ℃, 45 ℃ or 50 ℃ (see Figure 6).

Comparative Example 1

In Example 1 a glass slide glass substrate with only coarse step 1) was used.

Comparative Example 2

In Example 8 a low iron glass substrate was used which passed only step 1).

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 by a contact angle meter (KRUSS, DSA100), the results for all examples are summarized in Table 1, and the results for Examples 1, 5, and 6 2 is shown in the 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 the SEM photographs of Examples 1, 5, and 6 are shown in FIG. 2.

(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, Nanoman II), AFM images for Examples 1, 5, 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 (Lambda 35, Perkin Elmer), and the light transmittances of Example 8 and Comparative Example 2 are 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 Table 1 below.

Table 1

Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7	Example 8	Example 9	Example 10
Wet dildo143	115	135	142	53	93	154	130	See Figure 5	See Figure 6
Excellent a	Excellent a	Very bad b	Bad c	Excellent a	Excellent a	Very bad b	Excellent d	Good or excellent a	Good or excellent a

a; Excellent = higher light transmission than 'Comparative Example 1'

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

c; Poor = low light transmittance compared to 'Comparative Example 1'

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

<Description of the code>

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

Claims (12)

1. A coating solution composition comprising a silica precursor, a neutral catalyst, an alcohol, and a non-fluorine silane-based organic material.
2. 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.
3. 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.
4. The coating solution composition of claim 1, wherein the neutral catalyst is ammonium fluoride (NH ₄ F).
5. The coating solution composition of claim 1, wherein the non-fluorine silane-based organic material is chlorotrimethyl silane or octadecyltrichloro silane.
6. The coating solution composition of claim 1, wherein the alcohol is methanol, ethanol or isopropanol.
7. (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.
8. 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.
9. The method of claim 7, wherein the neutral catalyst is ammonium fluoride (NH ₄ F).
10. 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.
11. 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.
12. The method of claim 7, wherein the non-fluorine silane-based organic material is chlorotrimethyl silane or octadecyltrichloro silane.

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