JP2003238207A - Anti-fogging article and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart excellent anti-fogging characteristics and anti-fogging persistence to the surfaces of a windowpane, mirror, etc. <P>SOLUTION: A coating material consisting of a metal oxide or a metal oxide matrix is applied on the surface of the windowpane or the reflection mirror, such as the mirror, to form a coating film of 1 to 50 nm in mean surface roughness of the surface and thereafter the coating film is heated to ≥100°C, following which an anti-fogging treating liquid containing a surfactant is applied thereto in a temperature range of 30 to 100°C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The invention of this application relates to an antifogging article and a method for producing the same. More specifically, the invention of this application is provided in a window glass of an automobile or a building, a mirror used in a home or a barber shop, a mirror in a bathroom, a rear-view mirror of an automobile, a corner of a mountain road or an alley. It is possible to effectively prevent the occurrence of fog that adheres to the surfaces of glass and reflectors that are used in various ways in various places such as mirrors, and to maintain the antifog property of the antifog. The present invention relates to a new method, and an antifogging article provided with antifogging property by this method.

[0002]

2. Description of the Related Art The removal of fog adhering to the surfaces of window glass, mirrors and mirrors such as mirrors has become a problem not only from the viewpoint of comfort in daily life but also from the viewpoint of safety.

The cause of this fogging is that when the surface temperature of a reflecting mirror such as a window glass, a mirror or a mirror is lower than the atmospheric temperature of the atmosphere, the water in the air is condensed to form fine water droplets, It is well known that the minute water droplets are generated due to irregular reflection of light. Various measures have been heretofore attempted to prevent the occurrence of such fog, but basically, the following four are limited. (1) By constantly maintaining the surface temperature of the window glass, the reflecting mirror, or the like at the dew condensation temperature or higher, it is possible to prevent the dew condensation of water on those surfaces. (2) A water adsorption layer is provided on the surface of a window glass, a reflecting mirror, or the like to absorb water droplets condensed on the surface. (3) Applying water repellent treatment to the surface of window glass, reflector, etc.,
The water droplets that have condensed on the surface are dropped by their own weight. (4) By applying hydrophilic treatment to the surface of the window glass, reflecting mirror, etc., water droplets condensed on the surface are uniformly diffused to form a uniform water film to prevent irregular reflection of light.

[0004]

Various concrete methods have been tried based on the above basic idea. For example, as a specific method based on (1) above, a method is known in which a heating wire or a heater is attached to the inner layer portion of the window glass or the back surface of the reflecting mirror or the like to heat the window. However, the method of using a heat ray or a heater not only requires energy to generate heat, but also requires strict measures against earth leakage in a humid environment such as a bathroom. The method (2) above is a method of sticking a hygroscopic film or a non-woven fabric on the surface of a window glass or a reflecting mirror, but this method lacks in simplicity and absorbs and retains condensed water. Is limited.
That is, there is a problem that water that has once been adsorbed flows out again in a bathroom or the like where the water content is constantly high. Further, in the method (3), the surface of the window glass or the reflecting mirror is treated with a material having high water repellency so as to prevent water droplets from adhering to the surface of the window glass or the reflecting mirror. This is a method to prevent it from being held on the surface of a window glass or a reflecting mirror even if it adheres. However, a material having high water repellency so that fine water droplets that cause fogging can be naturally dropped by its own weight has not yet been developed and has not been used as an effective antifogging method.

Further, the method (4) is a method in which, contrary to the method (3), the surface of the window glass, reflecting mirror or the like is treated with a hydrophilic material to diffuse the condensed water droplets. In this method, a method of applying a surfactant to the surface of a window glass or a reflecting mirror to reduce the surface tension of water droplets attached, or
There is a method of coating the surface of a window glass or a reflecting mirror with a hydrophilic material. However, in the case of the method, there is a problem that the adhering water flows out of the surfactant, so that the effect of lowering the surface tension of water droplets disappears with the passage of time. Further, the method (1) has a problem that it is vulnerable to dirt during use. That is, in the method of
It is necessary that the surface of window glass, reflecting mirror, etc. be covered with a continuous hydrophilic material, and if any water repellent material adheres to the surface, a uniform water film disappears starting from that location. Cloudy will occur. In order to solve this, at present, it is attempted to decompose a pollutant by using a photocatalyst such as titanium oxide to maintain a clean hydrophilic surface at all times, but in an indoor environment such as a bathroom. In this case, since the supply of light energy is insufficient, the photocatalyst does not function sufficiently and pollutants cannot be decomposed satisfactorily. Aside from this, research using visible light catalysts is also in progress, but no effective visible light catalysts have been found so far, and it is currently effective for indoor mirrors in high-moisture atmospheres such as bathrooms. No anti-fogging function has appeared.

Therefore, the invention of this application solves the problems of the prior art as described above and realizes excellent anti-fog property,
Moreover, it is an object of the present invention to provide a new method for maintaining the antifogging property and an antifogging article realized by this method.

[0007]

The invention of this application is intended to solve the above-mentioned conventional problems. Firstly, the surface of a base material contains metal oxide fine particles and a metal oxide matrix as main components. After applying the coating material so that the average surface roughness (Ra) of the coating film surface becomes 1 to 50 nm, the coating film is heated to a temperature of 100 ° C. or higher, and then the interface is maintained while maintaining the temperature range of 30 to 100 ° C. Provided is a method for producing an antifogging article, which comprises applying an antifogging treatment liquid containing an activator. And 2ndly, the said method provides the manufacturing method of the antifogging article whose average surface roughness of a coating film surface is 1-10 nm, 3rdly, in the said method, metal oxide fine particles are silicon oxide. , aluminum oxide, zirconium oxide, and provides a method for producing anti-fogging articles, characterized in that at least one selected from the group consisting of titanium oxide, the fourth, in the above method, the metal oxide matrix R _n Si (OR)
_{4- n} (wherein n is a number of 0 to 3 and R is a hydrocarbon group of 1 to 8 carbon atoms), and is at least one of a hydrolyzate and a partial hydrolyzate of an organosilicon alkoxide. Fifth, the present invention provides the above-mentioned method, wherein the antifogging treatment liquid contains an anionic surfactant having sodium ion as a counter ion.

A sixth aspect of the invention of the present application is that a coating material having metal oxide fine particles and a metal oxide matrix as a main component is applied to the surface of the base material so as to have an average surface roughness of 1 to 50 nm.
To be heated to a temperature of 100 ° C. or higher, and then coated with an anti-fogging treatment liquid containing a surfactant liquid in a temperature range of 30 to 100 ° C. No. 7 provides an antifogging article in which the average surface roughness of the coating film surface is 1 to 10 nm.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention of this application has the characteristics as described above, and the state of implementation thereof will be described below. As described above, in the invention of this application, the average surface of the coating film is obtained by applying a coating material containing metal oxide fine particles and a metal oxide matrix as a main component on the surface of a glassy substrate such as a window glass or a reflecting mirror. Roughness (Ra) is 1-5
A 0 nm coating film is formed, the coating film is heated to 100 ° C or higher, and then an antifogging treatment solution containing a surfactant is applied while maintaining the temperature range of 30 to 100 ° C to produce an antifogging article. .

The type of metal oxide fine particles used in this method is not particularly limited, but it is selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide and titanium oxide having high surface free energy and chemical resistance. At least one type of metal oxide fine particles is suitable. The size of the particles is such that the average surface roughness of the surface coating film of a window glass, a reflecting mirror or the like is in the range of 1 to 50 nm,
A particle size of about 10 to 100 nm is suitable. The metal oxide matrix is Si (OR) ₄ or RSi (O) which has high surface free energy and chemical resistance when a coating film is formed.
It is preferably at least one of a hydrolyzate and a partial hydrolyzate of an organosilicon alkoxide represented by R) ₃ or R ₂ Si (OR) ₂ . In this case, the organosilicon alkoxide is preferably one having a relatively lower hydrocarbon group having a code R of 1 to 8 and particularly tetraethoxysilane or methyltrimethoxysilane. For the average surface roughness (Ra), the surface shape was measured with an atomic force microscope in a scanning range of 4 μm square. If the average surface roughness (Ra) is less than 1 nm, the surface is too smooth and sufficient hydrophilicity cannot be obtained and the antifogging performance deteriorates. Further, when the average surface roughness (Ra) exceeds 50 nm, the coating film itself diffuses light and loses transparency of the substrate such as glass and mirror. Especially when transparency is required, the average surface roughness (Ra) of the coating film surface is preferably in the range of 1 to 10 nm.

A coating film obtained by coating the surface of a window glass or a reflecting mirror with a coating material containing metal oxide fine particles and a metal oxide matrix as a main component is heated to 100 ° C. or higher to obtain coating strength and chemical resistance. In addition to improving the properties, the water content adsorbed on the outermost surface of the coating film evaporates and a chemically active surface state is obtained. If the temperature is lower than 100 ° C, the strength and chemical resistance of the coating film are insufficient and the adsorbed water on the outermost surface of the coating film does not evaporate, so that the desired effect as an antifogging agent cannot be obtained. After heating the coating film coated on the surface of the window glass or reflecting mirror to 100 ° C. or higher, an antifogging treatment liquid containing a surfactant on the surface of the coating film while maintaining the coating film temperature at 30 to 100 ° C. Apply with. The surfactant is not particularly limited as long as it has a large effect of lowering the surface tension of water, but it has a large effect of lowering the surface tension of water, and moreover, has a high transparency when applied to the surface of a window glass or a reflecting mirror. It is preferable to use the anionic surface active agent having sodium ion as a counter ion which is also excellent. Regarding the coating film temperature when treated with the antifogging treatment liquid, if the temperature is less than 30 ° C, the adsorption of the surfactant to the outermost surface of the coating film is insufficient, and if it exceeds 100 ° C, it is dried rapidly when the antifogging treatment liquid is applied. Therefore, the transparency of the surface is lost, so that it is necessary to set the temperature to 30 to 100 ° C.

[0012]

EXAMPLES The invention of this application will be described in detail below with reference to examples. In the examples, "parts" means "parts by weight" and "%" means "% by weight" unless otherwise specified.
In addition, although what is described in the following Examples 1 to 4 shows the preferable aspect of the invention of this application, it goes without saying that the invention is not limited to the following Examples.

<Example 1> Tetraethoxysilane (trade name: ethyl silicate 28 manufactured by Colcoat Co., Ltd.) 3
60 parts of methanol was added to 4 parts, and further 3 parts of water and 0.
By mixing 3 parts of 01N hydrochloric acid, mixing well using a disper, and heating in a 60 ° C. constant temperature bath for 2 hours,
A hydrolyzate and a partial hydrolyzate of an organosilicon alkoxide to be a metal oxide matrix were obtained. Next, a silica sol (trade name: ST) was added to the hydrolyzate and partial hydrolyzate of the organosilicon alkoxide as metal oxide fine particles.
-O NISSAN CHEMICAL INDUSTRIES, LTD. (Particle size 20 nm) (50 parts) was added, and the mixture was subjected to a polymerization reaction at 40 ° C for 1 hour, and then diluted with methanol so that the total solid content was 5%. A treatment liquid was obtained.

Sodium dodecylbenzenesulfonate (trade name: Neoperex F-25 manufactured by Kao Corporation) 4
96 parts of water was added to the parts to obtain an antifogging treatment liquid containing a surfactant.

A soda lime silicate glass plate (hereinafter referred to as a glass plate) is surface-polished with a cerium oxide-based abrasive, and the surface treatment solution is dropped on the surface washed with pure water and applied by a spin coater, Heat treatment was performed at 150 ° C. for 15 minutes. Then, when the temperature of the surface coating film reached 50 ° C., the antifogging treatment solution was dropped on the surface of the glass plate and applied by a spin coater to obtain an antifogging article.

<Example 2> Tetraethoxysilane was replaced with methyltrimethoxysilane (trade name: TSL8113EG
E anti-fog article was obtained in the same manner as in Example 1 except that the product was changed to Toshiba Silicone Co., Ltd.).

<Example 3> An antifogging article was obtained in the same manner as in Example 1 except that the silica sol was changed to zinc oxide sol (experimental product, particle size: 20 nm).

<Example 4> An antifogging article was obtained in the same manner as in Example 1 except that sodium dodecylbenzenesulfonate was changed to polyoxyethylene lauryl ether (trade name: Emulgen 108 manufactured by Kao Corporation).

Comparative Example 1 An antifogging article was obtained in the same manner as in Example 1 except that silica sol as fine particles of metal oxide was not added.

Comparative Example 2 Silica sol having a particle size of 200 nm
An anti-fog article was obtained in the same manner as in Example 1 except that the silica sol (1) was changed to the experimental sol.

<Comparative Example 3> An antifogging article was obtained in the same manner as in Example 1 except that the heat treatment temperature after coating the surface treatment liquid for coating the substrate was changed to 60 ° C for 15 minutes.

<Comparative Example 4> An antifogging article was obtained in the same manner as in Example 1 except that the temperature of the surface coating film at the time of applying the antifogging treatment liquid was changed to 120 ° C.

<Comparative Example 5> An antifogging article was obtained in the same manner as in Example 1 except that the temperature of the surface coating film at the time of applying the antifogging treatment liquid was changed to 20 ° C.

Comparative Example 6 An antifogging article was obtained in the same manner as in Example 1 except that the antifogging treatment liquid was not applied.

<Evaluation of Performance> (Surface Roughness) Regarding the surface roughness, the surface shape was measured with an atomic force microscope with a scanning range of 4 μm square, and the average surface roughness (Ra) was calculated. (Surface contact angle) With respect to the surface contact angle, the contact angle of the glass coated product with respect to 0.3 mg of water droplets was measured using a contact angle meter (Kyowa Interface Co., Ltd. CA-DT). (Transparency) Regarding transparency, the presence or absence of whitening on the surface of the antifogging article was visually evaluated. The evaluation criteria are as follows. ⊚: No whitening or clouding was observed. ○: Whitening or clouding was slightly observed, but no problem in practical use. ×: Practical problem due to whitening or clouding (anti-fog property) Anti-fog property was 90 ° C. The antifogging article was exposed to water vapor emitted from the beaker containing the hot water kept for 10 seconds, and the presence or absence of fogging was visually evaluated. The evaluation criteria are as follows. ⊚: No fog was observed at all ∘: Fogging was slightly observed, but there was no problem in practical use. After ultrasonic cleaning for 10 minutes, the antifogging article was exposed to water vapor emitted from a beaker containing hot water kept at 90 ° C. for 10 seconds, and the presence or absence of fogging was visually evaluated. The evaluation criteria are as follows. A: No cloudiness is observed. ◯: Fogging is slightly observed, but there is no problem in practical use. X: Haze causes practical problems. (Chemical resistance) With respect to chemical resistance, the state of the surface coating film coating the substrate surface was evaluated after the antifogging article was immersed in a 4% aqueous sodium hydroxide solution for 1 hour. The evaluation standard is
It is as follows. ⊚: The coating film is not deteriorated at all ◯: The coating film is slightly deteriorated ×: The coating film is eluted The results of these performance evaluations are shown in Table 1. Compared with Comparative Examples, Examples 1 to 4 all satisfy at a high level the performance required as an anti-fogging article such as transparency, anti-fogging property, anti-fogging durability, and chemical resistance.

[0026]

[Table 1]

[0027]

As described in detail above, according to the invention of the present application, it is possible to impart an excellent antifogging property to the surface of a reflecting mirror such as a window glass or a mirror, and further, an article having an excellent antifogging durability. Can be provided.

Claims (7)

[Claims] 1. A coating material containing metal oxide fine particles and a metal oxide matrix as a main component is applied on the surface of a base material so that the average surface roughness (Ra) of the coating film surface is 1 to 50 nm, and then 100 ° C. The coating film is heated to the above temperature, and then 30 to
A method for producing an antifogging article, which comprises applying an antifogging treatment liquid containing a surfactant while maintaining the temperature range at 100 ° C. 2. The manufacturing method according to claim 1, wherein the average surface roughness of the coating film surface is 1 to 10 nm. 3. The production method according to claim 1, wherein the metal oxide fine particles are at least one selected from the group consisting of silicon oxide, aluminum oxide, zirconium oxide and titanium oxide. 4. The metal oxide matrix is R _n Si (OR) _4-n.
(N is a number of 0 to 3 and R is a hydrocarbon group of 1 to 8 carbon atoms), which is at least one of a hydrolyzate and a partial hydrolyzate of an organosilicon alkoxide. 4. The manufacturing method according to any one of 1 to 3. 5. The method according to claim 1, wherein the antifogging treatment liquid contains an anionic surfactant having sodium ion as a counter ion. 6. A coating material containing metal oxide fine particles and a metal oxide matrix as a main component is applied to the surface of a base material so that the average surface roughness of the coating film surface is 1 to 50 nm, and then 100
An antifogging article characterized by being heated to a temperature of not less than 0 ° C and then being coated with an antifogging treatment liquid containing a surfactant solution in a temperature range of 30 to 100 ° C. 7. The antifogging article according to claim 6, wherein the average surface roughness of the coating film surface is 1 to 10 nm.