Visible light active photocatalyst tile

0001The present invention relates to visible light activated photocatalytic tiles.

0002A photocatalyst that can make IAQ (Indoor Air Quality) comfortable can be used by coating the surface of interior interior materials. Generally, a binder is used to coat and attach the photocatalyst to the substrate. However, the binder covers the surface of the photocatalyst in the process of binding to the photocatalyst, which reduces the surface exposed area of the photocatalyst. That is, if a binder is used for the photocatalyst coating, the surface reaction of the photocatalyst is reduced by the binder, and the performance is deteriorated.

0003In addition, titanium dioxide (TiO) is a typical photocatalytic substance.₂) Is used, which is a safe, non-toxic substance with excellent durability and wear resistance. However, since the bandgap energy for activating this is large, it can absorb only light having an ultraviolet wavelength or less, and there is a limit to its application to indoor decorative materials other than exterior materials.

0004Therefore, it is necessary to develop an interior material that is applied indoors and exhibits excellent photocatalytic performance based on its activity against visible light.

<p num="0005"> An embodiment of the present invention provides a visible light activated photocatalytic tile having excellent adsorption and removal performance for indoor harmful organic substances and excellent humidity control and antibacterial functions based on visible light activity performance.</p>

<p num="0006"> In one embodiment of the present invention, there is provided a visible light activated photocatalyst tile comprising a porous ceramic tile; and a photocatalyst layer formed on a coating composition containing an aqueous solvent and visible light activated photocatalyst particles on one surface of the tile. To do.</p><p num="0007"> The porous ceramic tile may include pores having an average diameter of about 1 nm to about 10 μm.</p><p num="0008"> The pore volume of the porous ceramic tile is about 0.01 to about 0.2 cm.³It may be / g.</p><p num="0009"> The porous ceramic tile may contain γ-alumina.</p><p num="0010"> The γ-alumina is at least one aluminum source selected from the group consisting of aluminum nitride, aluminum carbonate, aluminum chloride, aluminum chloride dihydrate, aluminum hydroxide, aluminum chloride, aluminum nitride, alumina sol, and combinations thereof. May contain a substance in which is phase-shifted.</p><p num="0011"> The porous ceramic tile may contain about 20 to about 50% by weight of the γ-alumina.</p><p num="0012"> The coating composition may contain from about 90 to about 96% by weight of the aqueous solvent and from about 4 to about 10% by weight of the visible light active photocatalytic particles.</p><p num="0013"> The aqueous solvent may contain 100% by weight of water.</p><p num="0014"> The visible light activated photocatalytic particles may contain a porous metal oxide; and metal particles supported on the porous metal oxide.</p><p num="0015"> The porous metal oxide may contain at least one selected from the group consisting of titanium oxide, tungsten oxide, zinc oxide, niobium oxide, and combinations thereof.</p><p num="0016"> The metal particles are a group consisting of tungsten, chromium, vanadium, molybdenum, copper, iron, cobalt, manganese, nickel, platinum, gold, silver, cerium, cadmium, zinc, magnesium, calcium, strontium, barium, and combinations thereof. It may contain at least one selected from.</p><p num="0017"> The visible light activated photocatalytic particles may contain the porous metal oxide in an amount of about 90% by weight to about 99.9% by weight and the metal particles in an amount of about 0.1% by weight to about 10% by weight.</p><p num="0018"> The visible light activated photocatalytic particles may have an average diameter of about 50 nm to about 500 nm.</p><p num="0019"> The coating composition may not contain an alcohol solvent and a binder.</p>

<p num="0020"> The visible light activated photocatalyst tile is excellent in air cleaning, deodorizing and antibacterial functions based on its activity against visible light, and can be applied indoors to exhibit excellent photocatalytic efficiency in the long term.</p>

0021Hereinafter, a realization example of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereto, and the present invention is only defined by the scope of claims described later.

0022In one embodiment of the present invention, there is provided a visible light activated photocatalyst tile comprising a porous ceramic tile; and a photocatalyst layer formed of a coating composition containing an aqueous solvent and visible light activated photocatalyst particles on one surface of the tile.

0023Coating compositions containing photocatalytic particles are typically made using a binder to improve adhesion to the substrate or using a solvent containing alcohol for rapid absorption and drying. However, such binders and alcohol solvents may reduce the exposed surface area of the photocatalytic particles, thereby reducing their adsorption and removal performance on harmful substances, especially toluene, which has a large molecular weight and is difficult to decompose or adsorb. ..

0024Therefore, the coating composition for producing the photocatalyst layer is characterized by using only an aqueous solvent without an alcohol solvent or a binder and containing the aqueous solvent and visible light active photocatalyst particles.

0025Further, the tile is a porous ceramic tile in order to ensure excellent adhesion and dispersibility on the tile surface even if the coating composition does not contain an alcohol solvent or a binder.

0026Specifically, the coating composition may contain from about 90 to about 96% by weight of the aqueous solvent and from about 4 to about 10% by weight of the visible light active photocatalytic particles. When the coating composition contains the aqueous solvent and visible light active photocatalyst particles in the above range, the coating composition may be effectively dispersed and attached to the surface of the porous ceramic tile, and the visible light active photocatalytic particles may be effectively dispersed and attached to the surface of the porous ceramic tile. Can achieve excellent photocatalytic performance. If the aqueous solvent is contained in less than about 90% and the visible light active photocatalyst particles are contained in excess of about 10%, there is a problem that the coating composition is not uniformly coated, and the adhesiveness to the tile is lowered. Therefore, there may be a problem that the photocatalytic performance is deteriorated. Further, when the aqueous solvent is contained in an amount of more than about 96% and the visible light active photocatalyst particles are contained in less than about 4%, the antibacterial function and the harmful substance removing function are not exhibited, and the required coating amount is obtained. This creates the necessary problems of many recovery processes.

0027The aqueous solvent is a solvent composed of 100% water, and the water may contain at least one selected from the group consisting of distilled water, ionized water, and combinations thereof, and the type of water is not limited as long as it is water. ..

0028The coating composition contains visible light-activated photocatalytic particles, which can exhibit the ability to remove harmful substances not only by ultraviolet light but also by visible light as having photoactivity with respect to visible light. Further, since the visible light activated photocatalyst particles show excellent efficiency even with an indoor light source, the visible light activated photocatalyst tile may be applied indoors without a separate light supply device.

0029For example, the visible light activated photocatalyst particles can have photoactivity for visible light in the wavelength range of about 380 nm to about 780 nm, and specifically, have an absorbance of about 20% for visible light having a wavelength of about 400 nm. It can be represented and can represent about 10% absorbance for visible light with a wavelength of about 500 nm.

0030In the visible photoactive photocatalytic particles, electrons and holes generated from the energy obtained by absorbing light generate peroxide anions or hydroxyl radicals, which decompose and remove harmful substances to purify and deprive the air. Has odor and antibacterial action.

0031Specifically, the visible light activated photocatalyst particles may contain a porous metal oxide; and metal particles supported on the porous metal oxide.

0032The porous metal oxide may contain at least one selected from the group consisting of titanium oxide, tungsten oxide, zinc oxide, niobium oxide, and a combination thereof as the porous particles.

0033Further, the metal particles may be, for example, a transition metal or a noble metal as a metal that imparts photoactivity to visible light. Specifically, the metal particles include tungsten, chromium, vanadium, molybdenum, copper, iron, cobalt, manganese, nickel, platinum, gold, silver, cerium, cadmium, zinc, magnesium, calcium, strontium, barium, and these. It may contain at least one selected from the group consisting of combinations.

0034For example, the visible light activated photocatalytic particles may contain tungsten oxide and platinum particles supported on tungsten oxide. In this case, the visible light active photocatalyst particles exhibit excellent photoactivity with respect to visible light, and excellent deodorization and deodorization by an indoor light source. The antibacterial function can be ensured.

0035The porous metal oxide contains pores, and the volume ratio of the pores may be about 5% to about 50%, and the specific surface area is about 50 m.²/ g or about 500m²It may be / g. When the porous metal oxide has a porosity and a specific surface area in the above range, the metal particles may be effectively supported, thereby ensuring excellent photoactivity to visible light and adsorbing harmful substances and adsorbing harmful substances. The removal performance can be further improved.

0036The visible light activated photocatalytic particles may contain the porous metal oxide in an amount of about 90% by weight to about 99.9% by weight, or may contain the metal particles in an amount of about 0.1% by weight to about 10% by weight. The metal particles may be supported on the surface of the porous metal oxide by a photo-deposit method, and at this time, by adjusting the contents of the porous metal oxide and the metal particles within the above range, it is excellent. Visible photoactive photocatalytic particles exhibiting catalytic effect can be produced.

0037For example, when the visible light active photocatalyst particles contain tungsten oxide and platinum particles supported on tungsten oxide, the tungsten oxide may be contained in an amount of about 90% by weight to about 99.9% by weight, and the platinum particles are contained in an amount of about 0.1% by weight. May be included in% to about 10% by weight.

0038If the porous metal oxide is contained in excess of about 99.9% by weight and the metal particles are contained in less than 0.1% by weight, it may be difficult to separate electron holes and exhibit sufficient photocatalytic activity. There is a risk that it cannot be done. Further, when the porous metal oxide is contained in an amount of less than about 90% by weight and the metal particles are contained in an amount of more than about 10% by weight, a sufficient number of electrons transferred by the porous metal oxide is sufficiently secured. There is a risk that the photocatalytic activity will decrease without being able to do so.

0039The visible light activated photocatalytic particles may have an average diameter of about 50 nm to about 500 nm, for example, about 50 nm to about 200 nm. The visible light active photocatalyst particles may be uniformly dispersed by having an average diameter in the above range by being applied to one surface of the porous ceramic tile in a state of being dispersed in an aqueous solvent, and the porous. It can quickly penetrate the pores of ceramic tiles and exhibit excellent adhesion. Further, since the visible light activated photocatalyst particles have an average diameter in the above range, an exposed area can be secured and excellent air purification and antibacterial functions can be exhibited.

0040As described above, the coating composition for forming the photocatalyst layer is such that it does not contain an alcohol solvent and a binder, and the exposed surface area of the visible light active photocatalyst particles is sufficiently secured, such as volatile organic compounds VOCs. It is possible to further improve the adsorption and removal performance of harmful substances.

0041In particular, the photocatalyst layer is excellent in adsorption and removal ability to toluene. Toluene has a large molecular weight and is usually a non-polar substance that is difficult to adsorb and decompose. Since the photocatalyst layer is formed from a coating composition containing an aqueous solvent and the visible photoactive photocatalyst particles without containing an alcohol solvent and a binder, the photocatalyst particles are excellent in adsorption and removal performance to harmful substances, and toluene is used. It shows an excellent removal rate for substances that are difficult to adsorb and decompose.

0042When the coating composition is applied to one surface of a porous ceramic tile without containing an alcohol solvent or a binder, a photocatalyst layer having excellent adhesiveness and dispersibility may be formed.

0043The porous ceramic tile may have suitable porosity properties to ensure the adhesion and dispersibility of the coating composition. Specifically, the porous ceramic tile may include pores having an average diameter of about 1 nm to about 10 μm, for example, pores having an average diameter of about 10 nm to about 1 μm. The "pores" are formed between the porous ceramic tile-forming particles, and are also referred to as open pores, and mean a space in which air can flow in and out smoothly. The average diameter of the pores refers to the arithmetic mean value of the pore diameters.

0044When the pores have an average diameter in the above range, excellent adhesion and dispersibility of the coating composition can be ensured, and at the same time, excellent humidity control effect and excellent strength by the humidity control function can be obtained. Can be secured. If the pores are less than about 1 nm, air does not flow in and out smoothly, so that a sufficient humidity control function may not be realized, and the adhesiveness and dispersibility of the coating composition may not be ensured. is there. Further, when the pores exceed about 10 μm, the strength of the visible light activated photocatalyst tile may be excessively reduced.

0045The pore volume of the porous ceramic tile is about 0.01 to about 0.2 cm.³It may be / g. The "pore volume" indicates the volume of pores contained in the porous ceramic tile as a value per unit mass of the tile. When the pore volume satisfies the above range, excellent adhesion and dispersibility of the coating composition can be ensured, and at the same time, excellent durability is prevented by preventing a decrease in strength of other tiles due to a decrease in density. And the humidity control function can be ensured.

0046The porous ceramic tile may contain γ-alumina to provide a humidity control function. The γ-alumina can be transferred to another structural phase by heat-treating the aluminum source, has a wide specific surface area and fine pore holes, and has a separation membrane, a catalyst, a catalyst carrier, and an adsorbent. It is a substance that can exhibit excellent properties.

0047The γ-alumina is formed on the pore surface contained in the porous ceramic tile-forming particles, and can have excellent humidity control and deodorizing functions. As a result, when the humidity is high, the γ-alumina has a function of absorbing moisture through the pores to lower the humidity in the room, and conversely, when the humidity is low, the moisture stored in the pores is released to the room. It has the function of increasing humidity. Further, the γ-alumina may be a regular γ-alumina, but in terms of cost saving and efficiency, specifically, γ-alumina obtained by phase-transitioning a low-priced aluminum source by heat treatment may be used. Good.

0048The γ-alumina is an aluminum source selected from the group consisting of aluminum nitride, aluminum carbonate, aluminum chloride, aluminum chloride dihydrate, aluminum hydroxide, aluminum chloride, aluminum nitride, alumina sol, and combinations thereof. It may contain a phase-transferred substance. However, the above-mentioned alumina source is not limited to those exemplified, and all aluminum sources that undergo a phase transition to γ-alumina by heat treatment may be included in this.

0049For example, aluminum hydroxide (Al (OH)₃) Is γ-alumina (Al₂O₃), The γ-alumina conversion rate of aluminum hydroxide may be about 0.6 to about 0.7.

0050The specific surface area of γ-alumina is about 150 m.²/ g or about 350m²It may be / g. The specific surface area of the γ-alumina is about 150 m.²If it is less than / g, it cannot show sufficient humidity control function, and it is about 350m.²Exceeding / g can lead to manufacturing process difficulties and can increase manufacturing costs.

0051The porous ceramic tile may contain about 20 to about 50% by weight of the γ-alumina. When the γ-alumina is contained in the content in the above range, the porous ceramic tile can secure appropriate porosity characteristics, and the adhesiveness and dispersibility of the coating composition can be further improved. As a result, the porous ceramic tile can ensure excellent humidity control function and strength. If the amount of γ-alumina is less than about 20% by weight, the moisture absorption / desorption humidity can be reduced, and if it exceeds about 50% by weight, the strength of the tile may be reduced.

0052The visible light activated photocatalyst tile can secure an air purifying function, an antibacterial function, and a humidity control function by including the porous ceramic tile and a photocatalyst layer formed from the coating composition on one surface thereof. In addition, it is possible to secure appropriate strength and ensure durability as an interior decoration material.

0053Specifically, the amount of moisture absorbed and released from the visible light activated photocatalyst tile is about 60 g / m.²Or about 100g / m²It may be. A comfortable indoor environment can be formed by the tiles exhibiting the amount of moisture absorbed and released in the above range. Specifically, through the moisture absorption and desorption amount, the visible light activated photocatalytic tile can form a medium humidity region having a temperature of about 25 ° C and a relative humidity of about 50% to about 75%, and minimizes the discomfort index due to moisture. It can be transformed to suppress the growth of mold and bacteria.

0054Further, the visible light activated photocatalytic tile may have a bending strength of about 10 MPa to 20 MPa. The "bending strength" refers to the maximum tensile stress at the time of fracture in the bending test, and indicates the maximum tensile stress at the time of fracture when the visible light activated photocatalyst tile is subjected to bending pressure. When the bending strength satisfies the above range, the visible light activated photocatalytic tile can secure excellent strength and can realize excellent durability as an interior decoration material.

0055Hereinafter, specific examples of the present invention will be presented. However, the examples described below are merely for exemplifying or explaining the present invention, and the present invention should not be restricted by this.

0056&lt;Manufacturing example&gt;<u style="single">Manufacturing Example 1: Manufacture of porous ceramic tiles</u> Aluminum hydroxide (Al (OH)₃) Is prepared by preparing a composition containing 20% by weight based on the solid content, pulverized through a ball mill, and the slurry obtained thereby is uniformly mixed through a spray drying step to obtain a granular powder containing 30% by weight of γ-alumina. Manufactured. Next, the granule powder was dry-press molded to form a pore with an average particle diameter of 10 nm by 0.1 cm.³A porous ceramic tile having a size of 150 mm × 150 mm × 7 mm (width × length × thickness) including a pore volume of / g was manufactured.

0057<u style="single">Production Example 2: Production of visible light-activated catalyst particles</u> Tungsten trioxide (WO₃) After dispersing the powder in water, add tungsten oxide (WO) to the solution.₃) 0.2 parts by weight of chloroplatinic acid (H) compared to 100 parts by weight₂PtCl₆) Was added to prepare a Pt / WO3 slurry. While stirring the slurry, irradiate the UV of a UV lamp (20 W) for about 30 minutes to irradiate the platinum (Pt) particles with the tungsten oxide (WO).₃) Doping into the particles. Then, tungsten oxide (WO) doped with the platinum (Pt) particles₃) Add 10% by weight of methanol solution to the slurry containing particles, and irradiate the slurry with UV from a UV lamp (20W) for about 30 minutes while stirring the slurry to make platinum (Pt) particles tungsten oxide (WO).₃), The visible light activated photocatalyst particles were produced.

0058&lt;Examples and Comparative Examples&gt;<u style="single">Example 1</u> A coating composition containing 5% by weight of visible light activated photocatalytic particles and 95% by weight of water according to Production Example 2 was produced. Next, the coating composition was applied to one surface of the porous ceramic tile of Production Example 1 and dried to form a photocatalyst layer to produce a visible light active photocatalyst tile.

0059<u style="single">Comparative example 1</u> Instead of the porous ceramic tile of Production Example 1, the coating composition has a pore volume of 0.01 cm.³The same method as in Example 1 above, except that it was applied to one surface of a tile having a size of 150 mm × 150 mm × 7 mm (width × length × thickness) with less than / g and dried to form a photocatalyst layer. Manufactured visible light activated photocatalytic tiles in.

0060<u style="single">Comparative example 2</u> Visible light activated photocatalytic particles of Production Example 2 5% by weight, isopropyl alcohol (IPA) 90% by weight, and TiO₂Visible light activated photocatalytic tiles were produced in the same manner as in Example 1 above, except that a coating composition containing 5% by weight of the sol binder was produced.

0061<u style="single">Comparative example 3</u> Visible light activated photocatalytic particles of Production Example 2 5% by weight, isopropyl alcohol (IPA) 90% by weight, and TiO₂A coating composition containing 5% by weight of the sol binder was produced. Next, this has a pore volume of 0.01 cm.³A visible light active photocatalyst tile was produced by applying it to one surface of a tile having a size of less than / g and having a size of 150 mm × 150 mm × 7 mm (width × length × thickness) and drying it to produce a photocatalyst layer.

0062&lt;Evaluation&gt;<u style="single">Experimental Example 1: Measurement of toluene removal rate</u> For the visible light activated photocatalyst tiles of the Examples and Comparative Examples, this is provided in a small chamber (ADTEC) having a volume of 20 L, and then air containing 0.2 ppm concentration of toluene is introduced into the chamber at a flow rate of 167 cc / min. It was continuously flushed so that the ventilation rate was 0.13 times / hr. An LED 20W module was used as the light source. The toluene removal rate was calculated according to the following general formula 1 by measuring the toluene concentration before entering the chamber (hereinafter, the first concentration) and the toluene concentration in the air after passing through the chamber (hereinafter, the second concentration). Concentrations were concentrated for a volume of 10 L using a DNPH (2,4-dinitrophenylhydrazine) cartridge and analyzed through HPLC (Agilent). The results are shown in Table 1 below.

0063[General formula 1] Toluene removal rate (%) = {(1st concentration-2nd concentration) / 1st concentration} x 100<tables num="1"><img id="000002" he="37" wi="160" file="JP2017536971A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0064With reference to Table 1 above, Example 1 relates to a tile containing a photocatalyst layer formed in a coating composition containing an aqueous solvent and visible light active photocatalytic particles, and instead of the aqueous solvent, an alcohol solvent and a binder. It was found that the solvent removal performance was remarkably excellent as compared with Comparative Example 2 regarding the coating composition using.

0065Further, the coating composition of Example 1 can be applied to one surface of a porous ceramic tile to ensure excellent adhesion and maximize photocatalytic performance, as in Comparative Example 1. It was found that the application itself is difficult because it is not so attached to one surface of the tile having no porosity, and the coating composition using an alcohol solvent and a binder as in Comparative Example 3 is attached to the tile having no porosity. However, it was found that the toluene removal performance was significantly lower than that of Example 1.