Substrate with photocatalytic coating

Description: TECHNICAL FIELD [Detailed description of the invention]

Substrate with photocatalytic coating The present invention is glass for utilities, or glass for transportation and buildings. Coating with photocatalytic properties for producing glass for various applications such as Glass, ceramic, or glassy ceramic as the main component Regarding lath substrates, especially transparent glass substrates. A thin layer is deposited on the surface of the glass to give it special properties, depending on the intended use. There are many studies to make the glass functional by stacking it. For example, alternating high and low Like the so-called anti-glare layer, which consists of a stack of layers with a high refractive index. There is a layer having various optical functions. Antistatic function and anti-freezing type heating function For example, a conductive thin layer containing a metal or a doped metal oxide as a main component is provided. Can be Regarding the thermal function of awnings or low emissivity, for example, silver type metal Alternatively, a thin layer containing a metal oxide or a metal nitride as a main component can be used. "Rain repellent In order to obtain the action, it has hydrophobicity with, for example, fluorinated organic silane as the main component. Layers can be provided. Here, the base material, especially glass, is referred to as "dirt-repellent". Needs still exist, i.e. appearance and surface properties do not change over time The goal is, for example, finger marks, planktonic organic substances present in the atmosphere. , Coagulable stains, etc., which gradually accumulate on the surface of the base material, are sequentially removed as soon as they occur. However, there is a need to reduce the frequency of cleaning and / or improve visibility. In fact, irradiation of the right wavelength causes oxidation of organic matter. A specific semi-based metal oxide that can initiate a radical reaction Conductor materials are known to exist, and these are generally "photocatalysts (photoca). It is referred to as a "talytic" or "photoreactive" material. An object of the present invention is to exhibit a remarkable "stain prevention" effect on a base material, which is industrially manufactured. It is possible to provide a photocatalytic coating on a substrate. The object of the present invention is mainly composed of glass, ceramic, or vitreous ceramic. It is a base material, especially transparent glass, with a small number of at least one surface thereof. Photocatalytic, at least partially containing crystalline titanium oxide The coating is applied. Titanium oxide is used when forming a coating on a substrate. It is preferably crystallized "on the fly". Titanium oxide, in fact, allows the organic matter deposited on its surface to be visible or ultraviolet. It is a type of semiconductor that decomposes under the action of wires. For this reason, glass with a "stain prevention" effect It is especially practiced to choose titanium oxide for the production of titanium oxide, which is the reason for this. Primarily this oxide provides good mechanical strength and chemical resistance for long-term effectiveness. Because it is presented. Of course, when the coating is directly exposed to many attacks But especially, glass is used in construction sites (buildings, etc.) and manufacturing lines (automobiles, etc.) It is important that the coating retains its integrity even when attached to). These attacks are repeated, either mechanically or by pneumatic gripping means. With the handling of, and when the glass is put in place, it wears out (of the window glass) Wipers, abrading cloth) and aggressive chemicals (SiO)₂Atmospheric pollutants like Exposure to quality, cleaning agents, etc.). In addition, at least partially crystalline titanium oxide has been selected. , It can have much better photocatalytic properties than amorphous titanium oxide This is because it has been proven. Preferably, anatase form, rutile form, or you It is a mixed form of rose and rutile, with a crystallinity of at least 25%, especially , Approximately 30-80%, present near the surface (this property is primarily a surface property is there). (Crystallinity is TiO in the coating₂Crystal Ti for the total weight of O₂It should be understood to mean the weight of. ) Also, especially in the case of anatase-type crystals, TiO that grows on the substrate.₂Crystal orientation A suitable orientation that affects the catalytic behavior of titanium oxide and significantly promotes the photocatalyst. (1,1,0) exists. This coating is included in this coating at least close to its surface Crystalline titanium oxide is 0.5-100 nm, preferably 1-50 nm, more preferred. Or have an average size of 10-40 nm, more preferably 20-30 nm It is advantageous to be produced with the form of a "crystallite" as a single crystal. fact As such, in this size range, titanium oxide has optimal photocatalytic activity. This is because crystallites of this size form highly active surface regions. Will. As described in more detail below, titanium oxide-based coatings Yes It can be obtained by various methods, for example, 1. Decomposition of titanium precursor 1) Known as liquid pyrolysis, powder pyrolysis, and chemical vapor deposition (CVD) of thermal decomposition methods. Pyrolysis in the gas phase, etc. 2) Immersion of technology using sol-gel, cell coating, etc. 2. Vacuum technology Reactive or non-reactive cathode sputtering, etc. Can be mentioned. Also, the coating is in addition to crystalline titanium oxide, at least one other tie. For example, oxidation of inorganic substances, especially in the form of amorphous or partially crystalline oxides. Silicon (or a mixture of oxides), titanium oxide, tin oxide, zirconium oxide, oxidation Aluminum can be included. This inorganic substance itself has a certain degree of light touch By exhibiting medial action, it can participate in the photocatalytic action of crystalline titanium oxide. However, as in the case of tin oxide and amorphous titanium oxide, crystalline TiO₂Compare to It may have a rather weak effect. At least one other such, at least partially crystalline titanium oxide Layers of "composite" oxides mixed with oxides can be advantageous from an optical point of view, In particular, TiO₂If you choose another oxide with a lower index of refraction than And by lowering the overall index of refraction of the coating, it is applied to the coating. It is possible to change the light reflection of the eclipsed substrate, especially by suppressing this reflection. Wear. This is, for example, TiO according to the production method described in Japanese Patent EP-0465309.₂/ Al₂O₃Layer consisting of, or TiO₂/ SiO₂A place where a layer consisting of is selected Applicable in that case. Here, of course, sufficient to retain sufficient photocatalytic activity TiO₂It is necessary for the coating to have a content rate. That is, coating The coating is at least 40% by weight of the total weight of the oxides inside, especially At least 50% by weight TiO₂It is considered preferable to include. It also has grafted oleophobicity that is stable or resistant to photocatalysts. / Or a hydrophobic layer can be laminated on the coating, eg rice Fluoride Olga as described in National Patent No. 5368892 and US Pat. No. 5389427 Patent application FR-94 filed on July 13, 1994, containing nosilane as the main component / 08734 (Compatible with patent number FR-2722493 and European patent EP-0692463) Of the perfluoroalkylsilanes described in, in particular the following equation: CF₃-(CF₂)_n-(CH₂)_m-SiX₃(In the formula, n is 0 to 12, m is 2 to 5, and X is a hydrolyzing group). Layer of. In order to increase the photocatalytic effect of titanium oxide in the coating according to the present invention, Different particles during coating, especially cadmium, tin, tungsten, zinc, auction By mixing metal particles and particles whose main components are um and zirconium, First and foremost, it is possible to expand the absorption band of the arting. Also, niobium, tantalum, iron, bismuth, cobalt, nickel, copper, ruteniu Insert a metal element of worm, cerium, or molybdenum into the crystal lattice of titanium oxide. It is also possible to increase the number of charge carriers by doping. In addition, this doping is the surface doping of titanium oxide or composite coating. Can only be done by surface doping, at least part of the coating Is done by covering with metal oxides or salts, the metals are iron, copper, ruthenium , Cerium, molybdenum, vanadium, bismuth. Finally, the photocatalytic phenomenon is associated with less of the metal oxide or coatings containing it. Partially covered with a precious metal in the form of a thin layer of platinum, rhodium, silver or palladium It can also be enhanced by increasing the yield and / or the reaction rate of the photocatalyst. it can. Such catalysts, such as those deposited by vacuum technology, are, in fact, acids. Improves the number and / or lifetime of radicals generated by titanium oxide and promotes chain reactions And can lead to the decomposition of organic matter To. Quite surprisingly, this coating is not just one property Shows two or more properties and is suitable for irradiation with visible light such as sunlight and / or ultraviolet light. Immediately upon exposure, due to the presence of titanium oxide in the photocatalyst, as mentioned above, organic Gradually eliminates the accumulation of dirt on things, and this decomposition is produced by a radical oxidation process. Jerking. Inorganic stains themselves do not decompose by this process and therefore follow It remains on the surface, but because the photocatalyst decomposes the binding organic matter, There is no cause for sticking to the surface or the surface, and they will be easily removed. Here, the permanent self-cleaning coating is preferably markedly hydrophilic and / Or exhibits a lipophilic exterior, which has three very beneficial effects: 1. Hydrophilicity allows complete wetting of water that can deposit on the coating. water When the phenomenon of condensation occurs, it does not accumulate cloudy water droplets that obstruct the view, and it is coated. There is a continuous thin film of completely clear water formed on the surface of the. This "anti-fog (a nti-condensation) action measures contact angle with water less than 5 ° when exposed to light This is especially noticeable when determined. 2. When water (especially rainwater) runs on a surface that has not been treated with a photocatalytic layer, many When rainwater drops adhere to the surface and remain and evaporate, they look bad, mainly due to inorganic substances. A dirty mark remains. In reality, the surface exposed to the surrounding air is immediately covered with a layer of dirt. We limit getting wet with water. These stains are other stains (especially In addition to (inorganic traces such as crystallization traces), it is affected by the atmosphere in which the glass is present. .. In the case of the photocatalyst surface, these inorganic stains are directly decomposed by the photocatalyst. I can't. In fact, it is brought about by photocatalytic activity Due to its hydrophilicity, most is removed. This hydrophilicity is, in fact, perfect for raindrops Causes spread. Therefore, there are no traces of evaporation anymore. Also, other If there is an inorganic stain on the surface, it will be washed by the water film or crystallized. If so, it is redissolved, so most of it is removed. "Inorganic" especially attracted by rain "Prevention of dirt" effect can be obtained. 3. Coupled with hydrophilicity, the coating can be lipophilic to this More like water, in the form of a continuous membrane that is less visible than a very local "stain" , Can "wet" organic stains deposited on the coating. .. " The "anti-staining effect of organic matter" is obtained by the action of two methods, namely, coaty. As soon as it deposits on the surface, it becomes invisible, and by the photocatalyst It gradually disappears due to the radical decomposition initiated. The coating should be selected to have a rather smooth surface. Can be done. In practice, some roughness may be beneficial for the following reasons: 1. Higher photocatalytic surface area can be formed and therefore higher Photocatalytic activity can be induced. 2. Has a direct effect on wetting. Roughness actually enhances wettability. Smooth hydrophilic The sexual surface can become more hydrophilic when roughened. In this case, "roughness "" Means the roughness of the surface and the porosity of the layer at least in part of the thickness of the layer. It should be understood to mean both the roughness that occurs. All of the above effects are more pronounced if the coating is porous and coarse. The rough photoreactive surface provides a striking hydrophilic effect. However, not much If excessive, the roughness is not optically acceptable for covering or accumulating dirt and / or Even the unclear appearance of the level It may be disadvantageous to do so. That is, TiO₂The coating with the main component is a roughness of about 2 to 20 nm, which is preferable. Sedimentation methods with a roughness of 5 to 15 nm have been demonstrated to be advantageous. This roughness is squared for a surface area of 1 square μm using an atomic force microscope. Evaluated by finding the root mean square (RMS) value. To such roughness The coating is hydrophilic, which is reflected in the contact angle with water. It can be less than 1 °. It also increases the porosity of the entire coating thickness. It has also been found to be beneficial. That is, the coating is TiO₂Only from If so, the porosity should be on the order of 65-99%, especially 70-90%. Preferably, this porosity is about 3.8 in this case TiO₂Against the theoretical density of It is indirectly defined as a percentage to do. One way to increase this porosity is , For example, by sol-gel type technology involving the deposition of organometallic type materials. Ting deposits, polyethylene glycol (PEG) type organic polymers -Is added to the solution of the organometallic precursor and the layer is cured by heating, then P Burns EG and increases porosity over the entire thickness of the layer. The thickness of the coating according to the invention can vary, preferably 5 nm. ~ 1 μm, especially 5 ~ 100 nm, especially 10 ~ 80 nm, especially 20 ~ 50 nm. In practice, the choice of thickness depends on various parameters and is based on Purpose of use of timber glass, TiO in coating₂Crystallite size, in substrate It is determined by the presence of a high proportion of alkali metals in. In the present invention, between the substrate and the coating, the function of the coating differs from that of the coating. Can also be placed with one or more separate thin layers that have an auxiliary function. In particular , Antistatic function, thermal or optical function, Anatase or rutile form of TiO₂Function to promote crystal growth of It functions as a layer that forms a barrier to the movement of specific elements that occur, the latter. In particular, the barrier to alkali metals, especially the base material is made of glass. In some cases, it functions as a barrier to sodium ions. Also, "anti-glare" consisting of alternating thin layers of high and low refractive indexes. Lamination of layers can also be provided, and according to the present invention, this coating is the final of the lamination. Make up the layer. In this case, the coating may have a relatively low index of refraction. Preferably, for example, a composite oxide of titanium and silicon can be mentioned. Antistatic and / or thermal function (eg, by providing power leads) The layer with heat, low emissivity, awning, etc.) is mainly composed of metal-type conductive material. Can be selected from, for example, silver, metal-doped oxide types For example, tin-doped indium oxide ITO and fluorine halogen Pinned tin oxide SnO₂: F, SnO including antimony₂: Sb, indium ZnO: In of zinc oxide doped with fluorine, Zn: F containing fluorine, aluminiu Examples include ZnO: Al containing zinc and ZnO: Sn containing tin. Also stoichiometric SnO of certain metal oxides lacking oxygen_2-xAnd ZnO_2-x(x &lt;2) is mentioned Is done. The layer having an antistatic function preferably has a surface resistance value of 20 to 1000 Ω. Good. Power leads can be provided to polarize this (eg, Applied voltage of 5 to 100V). This controlled polarization is on the coating It can suppress the deposition of dust of the order of mm that can be deposited, especially , Dry dust attached only by the action of static electricity, suddenly reverses the polarization of the layer This dust is eliminated by letting it. A thin layer with optical function reduces the reflection of light and / or the reflected color of the substrate. It can be selected to make it more colorless. In this case, refraction of the coating It is preferable to have a refractive index intermediate between the index and the refractive index of the substrate and an appropriate optical thickness. Also, aluminum oxide Al₂O₃, Tin oxide SnO₂, Indium oxide In₂O₃of May consist of oxides or composite oxides, or silicon carbonate or silicon nitride it can. To get the maximum suppression of reflected color, this thin layer has two materials surrounding it, That is, it is preferable that it is close to the square root of the product of the refractive index of the substrate and the coating of the present invention. .. Similarly, select an optical thickness close to λ / 4 (ie, the product of the geometric thickness and the index of refraction). Where λ is almost the average wavelength of visible light, about 500-5 It is 50 nm. Thin layers that have a barrier function against alkali metals are particularly silicon oxides and nitrogen. Compounds, oxynitrides, carbonitrides, or fluorine-containing aluminum oxide Al₂O₃: F young Or aluminum nitride can be selected as the main component. In fact, the base material It has proven to be useful when made of glass, which is according to the present invention. The movement of sodium ions into the coating adversely affects its photocatalytic properties To do. The nature of the substrate or sublayer is the connection of the deposited layers, especially in the case of CVD deposition. It has the additional advantage of promoting crystallization. That is, TiO by CVD₂Crystalline SnO during deposition₂The lower layer of: F is especially At deposition temperatures on the order of 400-500 ° C, it promotes almost rutile-shaped growth, On the other hand, the surface of the lower layer of soda-lime glass and silicon carbide is especially 400 ~ Induces anatase growth at deposition temperatures on the order of 600 ° C. All of these optional thin layers are vacuum cathode sputtering technology, Alternatively, the bank is deposited by a known method using other techniques such as solid phase, liquid phase or gas phase pyrolysis. Can be stacked. Each of the above layers can have multiple functions, but Each can also add functionality. Another object of the present invention is "stain prevention" (staining of organic and / or inorganic substances). And / or "anti-condensation" glass, where the above Integrated, double glazing or laminated double with tinging substrate It can be several units. Thus, the present invention is a glass, ceramic, or vitreous ceramic product. In particular, for the production of "self-cleaning" glass. This latter is a double moth Beneficial for building glass such as laths (then "inside" and / or " The coating can be placed "outside", i.e. on surface 1 and / or surface 4. is there. ). This is very difficult to clean glass and / or roof glass and airport glass It has been found to be particularly beneficial for glass that needs to be cleaned very often, such as glass. To. It is also related to transportation windows, where maintaining visibility is an essential safety standard. This coating can be applied to the front, side and rear windows of a car, especially the seat It is on the window side facing the seat. This coating can prevent the occurrence of fogging It can also remove dirty finger marks, nicotine and other organic stains, Organic matter is volatile released from the plastic interior of the car, especially the dashboard There is a plasticizer (sometimes known as "fogging"). Aircraft and steam Other means of transportation, such as cars, should also use windows with the coatings of the invention. And can find useful uses. There are many other potential uses, especially aquarium glass, over-the-counter. Windows, green houses, balconies, interior furniture, Street equipment, and even mirrors, TV screens, spectacle fields, or Examples include surface materials for cosmetic materials, clad materials, and tiles for exterior materials. As described above, the present invention makes these known products UV resistant, stain resistant, and sterilized. Functionalize them by imparting properties, anti-reflective properties, antistatic properties, antibacterial properties, etc. Can be made to. Another important use of the coating according to the invention is electrochromic. Glass, liquid crystal glass (including dichloromethane dye if desired), moth containing a system of suspended particles Combined with electrically controllable variable absorption glass such as lath and viologen glass It is an application. These glasses generally have multiple transparent substrates between them. An "active" element is placed on the outer surface of at least one of these substrates. The coating can be beneficially placed on the surface. Especially in the case of electrochromic glass, when this glass is in a colored state, Absorption results in some heating of the surface and deposits on the coatings of the invention Photocatalytic decomposition of carbonaceous substances can be promoted. Electrochromic glass Further details on the structure of the electrochromic laminated double glazing European patent application EP-A-0575207 can be referred to as described in the invention. The coating can be placed on surface 1. Another object of the present invention is the various applications for forming the coatings of the present invention. Rothes. Pyrolysis deposition techniques can be used, which are glass substrates If used, the coating is directly over the strip of float glass It is advantageous because it can be deposited continuously. Pyrolysis is performed in solid phase from one or more powders of one or more precursors of organometallic type. It can be carried out. In addition, thermal decomposition is performed on titanium chelate and / or titanium alcoholate organometallic nitrogen. It can also be carried out in a liquid phase rather than a solution containing a tongue precursor. There are few such precursors At least one different organometallic precursor is mixed. Titanium precursor properties and sedimentary streaks See patent FR-2310977, EP-0465309 for further details. can do. Pyrolysis is also TiCl by a technique known as CVD (Chemical Vapor Deposition).₄Halide species such as or titanium tetraisopropoxide species Ti (OiPr)₄of Do this in the gas phase, rather than at least one titanium precursor, such as titanium alcoholate. You can also do it. In addition, the crystallization of the layer is controlled by the type of lower layer as described above. You can also do it. In addition, other technologies, especially those combined with "sol-gel", are used for coating. Ings can also be deposited. "Dip" ("Dip coating" Also known as) or "cell coating" deposits using cells Various deposition methods such as are also possible. Also spray coating and laminating A laminar coating method is also possible, the latter technique being internationally patented. It is described in detail in Request WO-94 / 01598. These deposition methods will eventually Also, in general, at least one organometallic precursor of titanium, especially of the alcoholate species. After using the containing solution and coating one or both sides of the substrate with that solution, Pyrolysis. Also, with any deposition technique, at least two steps, not just one step. It may be advantageous to coat in the sequential process of If a thick coating is adopted, the entire thickness of the coating is of titanium oxide Observed to promote crystallization. Similarly, the coating with photocatalytic properties is annealed after deposition. It is beneficial to make sense. Heat treatment is one or more after the base material is coated. To pyrolyze the above organometallic precursors into oxides and to improve wear resistance , Basic for sol-gel or laminated coating technology, but This is not the case with pyrolysis techniques, where the precursor thermally decomposes as soon as it comes into contact with the substrate. I. Here, in the former case and the latter case, TiO₂Sedimentation after generation Subsequent heat treatment improves its crystallinity. Also, the heat treatment temperature of choice is that of the oxide. Allows proper control of crystallinity, anatase and / or rutile crystallinity I have something to do. Here, in the case of a base material made of soda-lime glass, a plurality of long-term aniri Photocatalytic activity due to excessive movement of the alkali metal from the substrate to the photocatalytic layer. May result in a decrease in. Substrate (if made of standard glass) and coating Use a barrier layer between the two, select a substrate made of glass of appropriate composition And, or use soda-lime glass with a surface from which alkali metals have been removed. That can eliminate this danger. Other useful details and features of the invention are limited to the following with reference to the accompanying drawings: It will be clarified by an example that is not done. FIG. 1 is a cross section of a glass substrate with a coating according to the present invention. FIG. 2 is a diagram of the so-called "dip coating" sol-gel deposition method. .. FIG. 3 is a diagram of the so-called "cell coating" deposition method. FIG. 4 is a diagram of the so-called spray coating deposition method. FIG. 5 is a diagram of the deposition technique by laminating coating. As schematically shown in FIG. 1, all of the following examples are transparent substrates 1 So-called "anti-staining" coating with titanium oxide as the main component on Is involved in the deposition of. Base material 1 is a transparent soda ash silica gala with a thickness of 4 mm, a length of 50 cm, and a width of 50 cm. Consists of lath. It goes without saying that the present invention is not limited to this particular type of glass. Nor. Also, the glass may be curved rather than flat. There is an optional thin layer 2 between the coating 3 and the substrate 1, which is an alkali metal. To form a barrier to diffusion and / or to reduce light reflection It is a layer mainly composed of silicon carbide (SiOC), which is the target, or is charged. A layer intended for prevention and / or a low radiation zone (without having such a significantly lower radiation effect) May be) and / or especially for the purpose of forming a layer that reduces the reflected color. Tin Oxide Doped with Tin O₂: F is the main component layer. Examples 1-3 Examples 1-3 relate to coating 3 deposited using the liquid phase pyrolysis method. this The operation was placed beside and above the float glass at the exit of the float bath chamber. It can be done continuously using an appropriate distribution nozzle. In this example already The operation is discontinuous using the movable nozzle arranged relative to the base material cut to a predetermined size. Sequentially, this substrate is passed through a nozzle that sprays the appropriate solution at a constant rate. Before, preheat in the oven to a temperature of 400-650 ° C. Example 1 In this example, there is no voluntary layer. Coating 3 is made up of two solvents Two types of organometallics dissolved in a mixed solvent of ethyl acetate and isopropanol. Titanium diisopropoxide of tongue precursor For solutions containing diacetylacetonate and titanium tetraoctylene glycolate And deposited. Recognize that it is possible to replace all precursors with other precursors of the same type Should be, specifically, another titanium chelate titanium acetylacetone, Titanium (methyl acetoacetate), titanium (ethyl acetoacetate), available Or titanium triethanolamine or titanium diethanolamine There are types. As soon as substrate 1 reaches the desired temperature in the oven, i.e. about 500 ° C. The material is passed under a nozzle that sprays the mixture at room temperature with compressed air. I let you. TiO with a thickness of about 90 nm₂A layer was obtained, but the substrate 1 against the nozzle The thickness is controlled by changing the passing speed and / or the temperature of the substrate. Can be This layer exhibits excellent mechanical behavior. Its wear resistance test shows the surface of solid glass Equivalent to what you get about. This can be bent and dip coated. This is blue That is, the scattered light transmittance of the coated substrate is less than 0.6%. (560nm D₆₅Measured by light source). Example 2 Following Example 1, however, a 73 nm thick Sn between substrate 1 and coating 3 O₂: F layer 2 was inserted. This layer is the heat of dibutyl tin difloride DBTF powder Obtained by the solution. Also, as described in patent application EP-A-0648196. It can also be obtained by a known method by thermal decomposition in the liquid phase or the gas phase. In the gas phase, monobutyltin trichloride and fluoride precursor (optionally H₂You can also use a mixture of O-type "mild" oxidizers) Wear. The refractive index of the obtained layer was about 1.9. Its surface resistance is about 50Ω Ta. In Example 1 above, the coated base material 1 mounted as double glazing is The coating is on surface 1 (the other substrate 1'is coated No, but with 12mm air layer has the same properties and dimensions as substrate 1), 26% The color saturation value at the reflection of 6.8% and the color saturation value at the transmission of 6.8% were exhibited. In this example 2, the color saturation (golden) in the reflection is only 3.6%, It was 1.1% of transmission. That is, SnO₂The lower layer of: F gives the base material antistatic properties due to its conductivity. It can also make its tones significantly more neutral in both transmission and reflection. This gives a favorable effect on the color tone of the substrate, and this color exhibits a relatively high refractive index. It is caused by the presence of titanium oxide coating. Large to the percentage of mm orders Proper power supply to polarize it to prevent the buildup of small size dust Can be done. In addition, this lower layer is a photocatalyst TiO.₂Suppresses the diffusion of alkali metals into the layer To. In this way, the photocatalytic activity is improved. Example 3 Following Example 2, however, in this example, the index of refraction is about 1.75 and the thickness is about 50 nm. A layer 2 containing silicon carbide as a main component is inserted between the base material 1 and the coating 3. Enter, this layer is rare with nitrogen, as described in patent application EP-A-0518755. SiH₄Obtained by CVD from a mixture of ethylene and ethylene. This layer is the basis Alkali metal (Na) generated from material 1⁺, K⁺) And alkaline earth metals (Ca⁺⁺) Is It is especially effective in preventing the tendency to spread toward the arting 3. Therefore, the photocatalytic activity is significantly improved. Also, SnO₂Like: F, base material ( It has a refractive index between 1.52) and coating 3 (about 2.30 to 2.35). Therefore, it is possible to reduce the coloring strength of the base material in both reflection and transmission. Light reflection value of the base material R_LCan be reduced as a whole. Examples 4-7 below relate to deposition by CVD. Example 4 ~ 7 Example 4 An example of this is as described in patent application EP-A-0518755 above. Directly deposited coating 3 by CVD on substrate 1 using standard nozzles Regarding letting. As a precursor, any of an organometallic compound or a metal halide It is still used. In this example, the organometallic compound is titanium tetraisopropi. Choosing a rate, this compound is highly volatile and widely usable at 300-650 ° C It is advantageous because of the effective temperature. In this example, sedimentation is performed at about 425 ° C and TiO₂The thickness of was 15 nm. Also, Tetra ethoxy Titanium Ti (OE)_t)₄Is also suitable, with halides Then TiCl₄Can be mentioned. Example 5 Do the same as in Example 4, but in this example, 15 nm TiO₂Layer on glass On a 50 nm SiOC underlayer deposited in the same manner as in Example 3, not directly deposited on It was deposited. Example 6 Do the same as in Example 4, but in this example, TiO₂Layer thickness is 65 nm It was. Example 7 Do the same as in Example 5, but in this example TiO₂Layer thickness is 6 It was 0 nm. From these Examples 4 to 7, the base material coated in this way is subjected to a wear test. Showed good mechanical behavior. In particular, TiO₂No layer peeling was observed won. Example 8 In this example, it is also known as "dip" (also known as "dip coating"). A technique combining sol-gel using the deposition method according to) was used. This principle is shown in Figure 2. Shown in liquid solution 4 containing one or more suitable precursors of coating 3 Immerse the base material 1 in the base material 1 and pull the base material 1 at a controlled speed using the motor device 5. I raised it. The choice of pulling speed adjusts the thickness of the solution remaining on the surfaces on the two sides of the substrate. Therefore, the solvent is evaporated and then the precursor is decomposed into oxides. The thickness of the coating after the heat treatment can be adjusted. 0.2 mol per liter of ethanol to deposit coating 3 Titanium tetra in a 1: 1 molar ratio in an ethanol solution containing tetrabutoxide Butoxide Ti (O-Bu)₄And a solution containing diethanolamine DEA for stabilization 4 or a mixture of the precursor and solvent described in Example 1 was used (titanium (diethanol). Aminate) Other precursors such as dibutoxide can also be used). The base material 1 can include a SiOC lower layer. Withdraw from each solution 4 After that, the base material 1 is heated at 100 ° C for 1 hour, and then the temperature is gradually increased to 550 ° C. Heated for about 3 hours. Coating 3 is obtained on each side, and this coating is a Highly crystalline TiO in the form of natase₂Met. Example 9 This example uses a technique known as "cell coating" and The principle is shown in Fig. 3. This is 6 and 7 of two substantially parallel planes, and two Including forming a narrow cavity defined by seals 8 and 9 of this At least one of these surfaces 6 and 7 consists of the surface of the substrate 1 to be treated. Then the cab The tee is filled with solution 4 of one or more precursors of the coating and then wet. Solution 4 is extracted in a controlled manner to form a varnish, eg When this solution is withdrawn using a permeate pump 10, it is on the surface of the base material 1. Leave a film of solution on. Cavity 5 is then retained for at least the time required for drying. Membrane is heat It is cured by treatment. Advantages of this technology over "dip coating" In particular, it is possible to process only one of the two surfaces of the base material 1, and it is a masking system. If is not adopted, there is no need for systematic. The base material 1 provided a thin layer 2 containing silicon carbide SiOC as a main component. In Example 6, the solution 4 described in Example 8 was used, respectively. Then TiO₂Coating The same heat treatment was performed to obtain G3. Coating 3 showed good mechanical durability. In SEM (scanning electron micrograph), the field effect has a diameter of about 30 nm. The morphology of the single crystal grains having is shown. The roughness of this coating is not rough Produces high wettability compared to wing. Also, these same solutions 4 are "spray coated" as shown in FIG. Can be used to deposit the coating by, solution 4 is static Sprayed into a mist on the base material 1, or a layered coating as shown in FIG. It can also be done by ting. In the latter case, stainless steel and teff Ron A base material 1 supported by vacuum suction on a support 11 composed of a tongue containing a solution. Passing over the box 12, the solution partially filled and integrated the grooved cylinder 14. The tank 12 and the cylinder 14 move over the entire length of the base material 1, and the mask 13 is Prevents the solvent from evaporating from solution 4 to temperature. Details about this technology are described above. International patent application WO-94 / 01598 can be referred to. Characterized by a deposited coating, "anti-condensation" and " In order to evaluate "dirt-repellent", the substrate obtained in the above example was used. And tested. -Test 1- This is a test for cloudiness. This is a photocatalyst and coating after wetting From observing changes in the structure (hydroxyl group, porosity, roughness level) Become. If the surface is photocatalytic, carbon-containing microfouling substances adhering to the coating Is decomposed over time and the surface is hydrophilic, which is why it is anti-fog. Also, Suddenly reheat the previously coated substrate and place it cold or simply breathe into the substrate Observe if tightness and cloudiness appear, and if so, measure the time Then measure the time it takes for the cloudiness to disappear. -Test 2- This is the hydrophilicity and lipophilicity of the coating 3 surface compared to the solid glass surface. The base material is left in the outside atmosphere for a week under natural light and darkness. Then, after exposure to ultraviolet light for 20 minutes, water droplets and DOP (diofuchil) on the surface By measuring drops of phthalate). -Test 3- It deposits a layer of organosilanes on a substrate to be evaluated and UV (UV) Because it is irradiated with A) and decomposed by a photocatalyst. To. Organosilane improves wettability, so the contact angle between the substrate and water during irradiation is , Indicates the state of decomposition of the adhesive layer. The rate of disappearance of this layer is related to the photocatalytic activity of the substrate. To. The attached organosilane is trifluorosilane octadecyltrichlorosilane ( OTS). Adhesion is done by immersion. The test device is a turntable that rotates from 1 to 6 equipped with a low-pressure UV lamp. Including. Place the test piece to be evaluated on the turntable and illuminate the surface to be evaluated with ultraviolet rays. Turn to the side of the shot. Depending on their position and the number of lamps lit, each test piece will be 0. 5W / cm²~ 50W / m²Receive UV irradiation. For example 1,2,3,8,9 Irradiation power is 1.8W / m²And for Examples 4-7, 0.6W / m²And .. The time for each measurement of the contact angle depends on the photocatalytic activity of the test piece under cloudy weather, 20 It was changed within a minute to 3 hours. The measurement was performed using a goniometer. Prior to irradiation, the glass exhibited a contact angle of approximately 100 °. This angle is 2 after irradiation If it is less than 0 °, the layer is considered to have broken down. Each test piece tested depends on the average disappearance rate of the layer, which is determined as nm / h. Characterized, i.e., this is the thickness of the deposited organosilane layer, less than 20 ° At the irradiation time (time to eliminate organosilane) that can reach the final steady value of It is the divided value. All of the above examples passed Test 1, i.e. breathe into the coated substrate. It remains completely transparent when tightened, whereas uncoated groups A very visible cloudy layer adhered to the material. Samples of each example were subjected to Test 2, and the coated substrate was subjected to UV irradiation. Contact angle with water and dioctyl phthalate below 5 ° showed that. In contrast, solid glass has a contact angle of 40 ° with water under the same conditions. The contact angle with diofthylphthalate at 20 ° was shown. The results of Test 3 of the coated substrate in the above example are summarized in the table below. Ta.<img file="JPH11512337A_D0001.tif" /> Regarding the above table, it can move out of the glass, especially in the presence of a lower layer of SiOC. Due to the barrier effect on alkali metals and alkaline earth metals, TiO₂including It can be seen that it enhances the photocatalytic activity of the coating (comparison of Examples 4 and 5 or Examples 6 and 7). ). Also, TiO₂It has been found that the thickness of the coating, including, plays a role (Example 1). 3), i.e., have a thickness greater than the average size of a single crystal or "crystallite" TiO₂Better with coating It can be seen that a good photocatalytic effect can be obtained. In fact, the TiO obtained by CVD₂The coating is 20 ~ 30n It shows highly developed crystallization with a crystal size on the order of m. Example 6 (65 nm TiO₂) Photocatalytic activity is shown in Example 4 (15 nm TiO).₂Only) significantly more than that You can see that it is expensive. Therefore, T is at least twice the average diameter of the crystals contained. iO₂It is advantageous to apply a coating. Alternatively, as in Example 5 Thin thickness TiO₂Keep the coating, but with the right properties and the right thickness of the underlayer Select and TiO as much as possible from the first layer of crystallites₂Can also be crystal-grown .. TiO₂Crystallization of coatings deposited by methods other than CVD It was observed that it was slightly inferior. However, as mentioned above, slightly inferior crystals All factors such as conversion are subject to optimization, and relatively low catalytic activity is relatively inexpensive. It is also in harmony with the advantage of being able to use a less complex deposition process. Ma Also, if necessary, the appropriate lower layer is TiO₂Uses doping to improve catalytic activity It can also be increased. Also, from the comparison of Examples 2 and 3, the properties of the lower layer are the crystal morphology, and in fact, the coaty. It has been confirmed that it affects the photocatalytic activity of