Photochemical catalyst complex and its prepn.

Photocatalyst composite and preparation method thereof

The invention relates to a photocatalyst composite and a preparation method thereof. The composite includes a matrix on which photocatalyst particles are adhered.

The photocatalyst particles are irradiated by light waves with a wavelength not less than the band gap energy to make electrons transition to the conduction band under light excitation, and at the same time generate corresponding vacancies in the valence band. Humans have used the strong reduction ability of electrons and the strong oxidation ability of the vacancies generated by light excitation in the decomposition and purification process of organic matter, as well as the decomposition process of water. The photocatalyst particles used in this type of processing are usually deposited on a substrate whose size is larger than the particles to prevent these particles from spreading in the atmosphere or being discharged from the processing system, after which the photocatalyst and the processing system are easily combined. Separate. One method of depositing photocatalyst particles on a substrate includes sintering the photocatalyst particles on the substrate at a temperature of 400° C. or higher to make these particles adhere to the substrate, or adopting another method. The method includes A precursor is sprayed onto a substrate heated at a temperature of about 400°C, and the precursor can be converted into a photocatalyst by thermal decomposition, thereby binding the particles to the substrate. In addition, another method of fixing photocatalyst particles has been proposed, that is, using a certain type of fluorinated polymer. For example, Japanese Patent Application Publication Hei 4-284851 discloses a method including laminating a mixture of photocatalyst particles and a fluorinated high polymer, and compressing the laminate under pressure. Japanese Patent Application Publication Hei 4-334552 discloses a method that includes heating and melting a fluorinated polymer to bind photocatalyst particles.

Recently, an effort has been made to use photocatalyst particles to decompose harmful substances, malodorous substances, and oily substances in garbage generated in daily life in a residential environment, as well as for the purification and disinfection of garbage. Therefore, the photocatalyst particles have found a wide range of applications. Based on this consideration, there is still a need for a method that can firmly bond the photocatalyst particles to any substrate, and this bond can be maintained for a long time without losing its photocatalytic effect.

Unfortunately, the above-mentioned methods of the prior art have the defects of insufficient bonding strength and easy delamination under external pressure, and all need to be heated at high temperatures, which makes them unable to be applied to heat-labile substrates such as plastics. Internal materials such as office walls and the surfaces of various products that are difficult to heat, etc. In addition, the high-temperature heat treatment reduces the specific surface area of the photocatalyst particles, thereby causing their photocatalytic effect to weaken. Moreover, these methods may require special means such as bonding under pressure or heating and melting devices.

An object of the present invention is to provide a photocatalyst composite comprising a matrix on which photocatalyst particles are bound by a binder that is not very degradable.

Another object of the present invention is to provide a method for preparing the photocatalyst composite.

Another object of the present invention is to provide a coating composition using the photocatalyst composite.

Figure 1 shows the change in weight loss per unit area of the binder in the photocatalyst composite after irradiating samples A and C from the examples and sample E from the comparative example with black light.

The inventor of the present invention has researched and developed a method that can firmly bond the photocatalyst particles to any substrate within an extended period of time without damaging the photocatalytic effect of the particles. The present invention is based on the following findings: (1) When the photocatalyst particles are bonded to the substrate with a binder, the photocatalytic effect of the photocatalyst particles may decompose and deteriorate the binder, resulting in the photocatalyst particles. Stick off the matrix. However, with a less degradable binder, the photocatalyst particles can be bonded to any substrate, but the particles will not be separated from the substrate, and unexpectedly, the photocatalyst of the present invention shows sufficient photocatalysis. (2) When the amount of photocatalyst particles is 5-98% (based on the total volume of the photocatalyst particles and the less degradable binder), the photocatalyst particles can be bonded to the substrate without weakening the production The photocatalytic effect of the photocatalyst composite. (3) The use of organic binders such as fluorinated polymers and siloxane-based polymers or inorganic binders as binders that are not very degradable can minimize the photocatalyst particles' light Decomposition and degradation due to the action of the catalyst enable the photocatalyst particles to be firmly bonded for a long time. Especially preferred fluorinated polymers mainly include vinyl ether and/or copolymers of vinyl ester and fluoroolefin. (4) The preferred photocatalyst particle is titanium dioxide, which has a strong photocatalytic effect, high chemical stability, and non-toxicity. (5) A method of bonding photocatalyst particles, which can be applied to make the surface of various products relatively easy to have photocatalytic properties, and the photocatalytic effect can be easily used in household appliances, which is the most convenient and easy way to use. The method includes the steps of arranging photocatalyst particles and a less degradable adhesive on a substrate, and then fixing the adhesive, or more specifically, including the steps of coating or spraying the photocatalyst particles , Adhesive and solvent coating composition, the photocatalyst particles and the less degradable adhesive are placed on the surface of the substrate such as different products, and then the step of fixing the adhesive.

That is to say, the present invention is to provide a photocatalyst composite, which includes any matrix on which photocatalyst particles are firmly bonded within an extended period of time, and the photocatalytic effect of the particles is not lost during the period of time. .

The present invention is a photocatalyst composite, which includes a matrix and photocatalyst particles bonded to it by a less degradable binder. In the present invention, the term "less degradable adhesive" refers to an adhesive that has an extremely reduced degradation rate due to the photocatalytic action of the photocatalyst particles. The weight loss (measured according to the method shown in the following examples) is 10% or less, preferably 5% or less, more preferably 3% or less, and most preferably 1% or less. A weight loss of more than 10% indicates that the binder has undesirably severe decomposition or degradation, and a large amount of photocatalyst particles are released at the same time. The less degradable adhesives used in the present invention include, for example, inorganic adhesives such as silicon compounds, such as water glass, colloidal silica, polyorganosiloxane, etc., phosphates such as zinc phosphate, aluminum phosphate, etc., phosphoric acid Dihydrogen salt, cement, lime, gypsum, enamel frits, glass lining glaze, paste, organic adhesives such as fluorinated polymers, siloxane-based polymers, etc., these adhesives can be two or more Use two or more in combination. In view of bonding strength, inorganic adhesives, fluorinated polymers and siloxane-based polymers are particularly preferred. Usable cements include, for example, Portland cement such as quick hardening cement, ordinary cement, moderate heat cement, sulfate-resistant cement, white cement, oil well cement, geothermal well cement, mixed cement such as fly ash cement, sulfate waste residue, silica cement , And blast furnace cement, high alumina cement and so on. Available plasters include, for example, plaster plaster, lime plaster, dolomite plaster and the like. The fluorinated polymers used include, for example, crystalline fluorinated resins such as polyvinyl fluoride, polyvinylidene fluoride, polytrifluorochloroethylene, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-trifluoroethylene Fluoro-chloroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, amorphous fluorinated resin such as perfluorocyclic polymer, vinyl ether-fluoroolefin copolymer, vinyl ester-fluoro Olefin copolymers, various fluorinated elastomers, etc. Particularly preferred fluorinated polymers mainly include vinyl ether-fluoroolefin copolymers and vinyl ester-fluoroolefin copolymers because they are not easily dispersed or degraded and are easy to handle. The siloxane-based polymers used include linear siloxane resins, acryl-modified siloxane resins, various siloxane elastomers, and the like.

The term "photocatalyst particles" used in the present invention refers to those particles capable of exhibiting a photocatalytic effect when irradiated with radiation having a wavelength not less than the forbidden band width of the band. The photocatalyst particles used include one or a combination of two or more known metal compound semiconductors, such as titanium dioxide, zinc oxide, tungsten oxide, iron oxide, strontium titanate, and the like. Particularly preferred is titanium dioxide with strong photocatalysis, high chemical stability and non-toxicity. In addition, in the inside and/or surface of the photocatalyst particles, it is preferable to include at least one metal and/or its compound as the second component, because it can make the prepared photocatalyst particles have stronger photocatalysis. Function, the metal is selected from V, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Pt and Au. The aforementioned metal compounds include, for example, metal oxides, hydroxides, hydroxides, sulfates, halides, nitrates, and even metal ions. The content of the second component can vary according to its type. A preferred photocatalyst particle that may contain the aforementioned metal and/or metal compound is titanium dioxide. The content of the photocatalyst particles is preferably 5-98% by volume, based on the total amount of the photocatalyst particles and the less degradable binder. When the content of the photocatalyst particles is less than the above range, the photocatalytic effect of the finished photocatalyst is undesirably weakened, but when the content is higher than the above range, the bonding strength is also undesirably weakened. When cement or gypsum is used as a less degradable binder, the content of photocatalyst particles should preferably be 5-40%, most preferably 5-25%. Or, when other organic or inorganic binders except cement and gypsum are used as less degradable binders, the content of photocatalyst particles should preferably be 20-98%, more preferably 50-98%, and most preferably 70-98%. 98%.

The photocatalyst particles used in the present invention can be prepared by any known technique. For example, there are several methods, including, (1) includes heating and hydrolyzing a titanium compound such as titanyl sulfate, titanium chloride, titanium alkoxide, etc., if necessary, a method of thermal hydrolysis in the presence of nucleation seed crystals, (2) Including the method of adding an alkali and, if necessary, neutralizing general titanium compounds such as titanium oxysulfate, titanium chloride, titanium alkoxide, etc. in the presence of nucleation seed crystals, (3) Including vapor phase oxidation of titanium chloride, The method of titanium alkoxide, etc., (4) includes a method of burning or hydrothermally treating the titanium dioxide obtained by any one of methods (1) and (2). Those titanium oxides obtained by method (1) or hydrothermal treatment at 100°C or higher are particularly preferred because of their strong photocatalytic effect. The term "titanium oxide" used in the present invention refers to those so-called hydrated titanium dioxide, hydrated titanium dioxide, metatitanate, orthotitanate, and titanium hydroxide in addition to titanium dioxide, regardless of their crystal system. In order to make the inside and/or surface of the photocatalyst particles contain at least one metal selected from the group consisting of V, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ag, Pt, and Au as the second component, and / Or a compound thereof, a method that can be used includes adding the adsorbed metal and/or compound during the preparation of the photocatalyst particles; or adopting a method including adding the adsorbed metal and/or compound after the photocatalyst particle is prepared. When heating, or when necessary, reducing.

The substrate used in the present invention includes inorganic products such as ceramics and glass, organic products such as plastics, elastomers, wood and paper, and metal products made of metals such as aluminum or alloys such as steel. There are no strict restrictions on the size and shape of the substrate, and even coated products can be used.

In the present invention, it is preferable to bond both the photocatalyst particles and an adsorbent on the substrate with a binder that is not very degradable because of the co-action of adsorbing the processed object. The adsorbent used includes commonly used adsorbents such as activated carbon, zeolite, silica gel, and so on.

In another aspect of the present invention, a first layer composed of a binder that does not contain any photocatalyst particles is provided on the substrate, and then, a first layer composed of a less degradable binder and photocatalyst particles is provided on the first layer. Second floor. The first layer without photocatalyst particles is provided to form a firm connection between the substrate and the second layer containing photocatalyst particles, so that the photocatalyst particles are more firmly bonded to the substrate and maintained for a longer period of time. In addition, the first layer should preferably contain inorganic particles that have no photocatalytic effect and serve as fillers. The inorganic particles used include particles of titanium dioxide, silicon oxide, aluminum oxide, magnesium oxide, etc., and the surface of the particles is coated with silicon oxide, aluminum oxide, or zirconium oxide.

The photocatalyst composite of the present invention can be prepared as follows: the photocatalyst particles and the less degradable adhesive are placed on at least a part of the substrate, and then the adhesive is fixed, so that the photocatalyst particles are bonded to the substrate through the adhesive on. In the present invention, in particular, the photocatalyst particles and the less degradable binder should preferably be dispersed in a solvent to prepare a coating composition, and then coated or sprayed on the substrate to remove the photocatalyst particles and the less degradable binder. The adhesive is disposed on at least a part of the substrate. The solvent used includes water, and organic solvents such as toluene, alcohol, and so on. The less degradable binders contained in the coating composition include those mentioned above which should preferably be soluble in the solvent used. In the present invention, the less degradable binder contained in the coating composition is preferably one or more polymers selected from fluorinated polymers and siloxane-based polymers. The amount of photocatalyst particles is 5-98V%, preferably 20-98V%, more preferably 50-98V%, most preferably 70-98V%, based on the total amount of photocatalyst particles and less degradable binder. The coating composition can be formulated with crosslinkers, dispersants and fillers. The crosslinking agent used includes crosslinking agents commonly used in the isocyanate family and the melamine family, and the dispersing agent used includes a coupling agent. In particular, when the content of the photocatalyst particles in the coating composition is 40-98% by weight, based on the total amount of the photocatalyst particles and the less degradable binder, it is preferable to formulate the coating composition with a coupling agent. The amount of coupling agent added should preferably be 5-50%, more preferably 7-30%.

The coating composition can be used by coating or spraying according to any commonly used coating technique or commonly used spraying technique such as spraying to dispose the photocatalyst particles and the less degradable binder on at least a part of the substrate. Coating techniques include dip coating, dip coating, spin coating, knife coating, roll coating, wire rod coating, and reverse roll coating. If necessary, before coating or spraying the photocatalyst particles and the less degradable binder on the substrate, an organic binder such as acrylic resin, epoxy resin, polyester can be coated or sprayed on the substrate. Resin, melamine resin, polyurethane resin, alkyd resin, etc., or the above-mentioned less degradable adhesive, to form the first layer, and then on the first layer, the composition is coated or sprayed, Provide a second layer composed of photocatalyst particles and a less degradable binder. The organic adhesive may be a commonly used adhesive.

After coating or spraying, the composition is fixed to become the photocatalyst composite of the present invention. The fixation can be done by drying, irradiating with ultraviolet rays, heating, cooling, or using a crosslinking agent, etc., at a temperature lower than 400°C, preferably from room temperature to 200°C. At this point, a temperature higher than 400°C may cause undesirable thermal degradation of the binder, making the photocatalyst particles easily detached. The present invention preferably adopts a method of fixing by isocyanate family and melamine family crosslinking agents.

The photocatalyst composite of the present invention can purify and disinfect neighboring products containing harmful substances, malodorous substances and oily substances under irradiation with rays with a wavelength not less than the band gap energy, and at the same time decompose such substances. The radiation used for irradiation includes light (including ultraviolet rays), such as sunlight, and light from fluorescent lamps, black light lamps, halogen lamps, xenon flash lamps, mercury lamps, and the like. Particularly preferred light includes near-ultraviolet rays of 300-400 nm. The intensity and time of irradiation with light can be conventionally determined according to the amount of materials to be processed.

The present invention will be further explained below with reference to some examples.

Example 1 Add sodium hydroxide to acidic titanium dioxide sol obtained by heating and hydrolyzing titanium oxysulfate (CS-N, available from Ishibara Sangyo Kaisha, Ltd.), adjust the pH to 7, then filter and wash. Water was added to the obtained titanium dioxide wet cake to prepare a slurry of 100 g/l (represented by TiO2). NaOH was added to the slurry to adjust the pH to 10, and then hydrothermally treated in an autoclave at 150°C for 3 hours. Add nitric acid to the slurry after hydrothermal treatment to neutralize to pH 7, filter, wash with water, and dry at 110° C. for 3 hours to obtain titanium oxide.

In a paint shaker, vibrate the mixture of the ingredients shown below for 3 hours to fully mix and disperse into a coating composition. The LUMIFRON LF 200C shown below is a fluorinated polymer, which mainly includes a copolymer of vinyl ether and fluoroolefin. Titanium oxide 9.80g fluorinated polymer (LUMIFRON LF200C, available from Asahi Glass Co., Ltd) 0.80g isocyanate-based hardener 0.16g titanium coupling agent (PLANEACT 338X, available from Ajinomoto Co., Inc) 1.00 The coating composition of the above formula was coated on a 20 cm2 glass plate with 23.60 ml of toluene and dried at 120°C for 20 minutes to form the photocatalyst composite of the present invention (Sample A). The titanium dioxide content of this sample A is 90V%, based on the total amount of titanium oxide and the less degradable binder.

In Example 2, the same titanium oxide as in Example 1 was used, and the mixture of the components shown below was vibrated in a paint shaker for 3 hours to fully mix and disperse to form a coating composition. Titanium oxide 7.64g fluorinated polymer (LUMIFRON LF200C, available from Asahi Glass Co., Ltd.) 2.36g isocyanate-based hardener 0.47g titanium coupling agent (PLANEACT 338X, available from Ajinomoto Co., Inc.) Coating the coating composition of the above formula on a 20cm2 glass plate with 0.76g of toluene and 22.50ml, and drying at 120°C for 20min to become the photocatalyst composite of the present invention (sample B). The titanium dioxide content of the sample B is 70V %, based on the total amount of photocatalyst particles and less degradable binder.

In Example 3, the same titanium oxide as in Example 1 was used, and the mixture of the components shown below was vibrated in a paint shaker for 1 hour to fully mix and disperse to form a coating composition. Titanium oxide 9.8g polymeric organosiloxane-based inorganic adhesive, a mixture of T2202A and T2202B in a 3:1 ratio, available from Japan Synthetic rubber Co., Ltd.) 2.7g isopropanol 21.5ml mix the above formula The coating composition was coated on a 20cm2 glass plate and dried at 180°C for 10min to become the photocatalyst composite of the present invention (Sample C). The content of titanium dioxide in this sample C is 90% by weight, based on the total amount of photocatalyst particles and less degradable binder.

Example 4 Add NaOH to the acidic titanium dioxide sol obtained by heating and hydrolyzing titanium oxysulfate (CS-N, available from Ishihara Sangyo Kaisha, Ltd.), adjust the pH to 7, filter and wash. The prepared titanium dioxide wet cake was dried at 110°C for 3 hours to become titanium oxide.

The mixture of the following ingredients was vibrated in a paint shaker for 3 hours to fully mix and disperse to form a paint composition. Titanium oxide 7.0g polymeric organosiloxane-based inorganic adhesive T2202A and T2202B are mixed in a ratio of 3:1, available from Japan Synthetic Rubber Co., Ltd.) 4.3g isopropanol 22.5ml

The coating composition of the above formula was coated on a 20cm2 glass plate and dried at 180°C for 10 minutes to become the photocatalyst composite of the present invention (Sample D). The content of titanium dioxide in this sample D is 80V%, based on the total amount of photocatalyst particles and less degradable binder.

In Comparative Example 1, the same titanium oxide as in Example 1 was used, and a mixture of the following components was vibrated in a paint shaker for 1 hour to fully mix and disperse to form a paint composition. Titanium oxide 9.8g vinyl acetate-acryl copolymer (BONCOAT 6290, available from DainipponInk & Chemicals, Inc.) 0.7g water and 24.8ml apply the above-mentioned coating composition on a 20cm2 glass plate, 120 Dry at °C for 10 min to make it into a photocatalyst composite (Sample E). The content of titanium dioxide in this sample E is 90V%, based on the total amount of titanium oxide and binder.

The surface of each sample of the photocatalyst composite (sample AE) obtained in the example and the comparative example was exposed to black light with an ultraviolet intensity of 7 mW/cm 2 for 5 hours. The binder in the photocatalyst composite was weighed before and after irradiation with black light to determine the weight loss. As a result, no weight loss was observed in the sample AD of the present invention, indicating that the adhesive was not decomposed. On the other hand, the weight loss of the comparative sample E without any less degradable adhesive was 85%, indicating that most of the adhesive was decomposed by the photocatalysis of titanium oxide. In addition, it was observed that the sample E turned yellow and the titanium dioxide particles were partially detached. The change in the weight loss of the binder in the photocatalyst composite caused by the black light irradiation of each sample AC of the example and sample E of the comparative example is shown in FIG. 1. Samples A and B from Examples 1 and 2 contain coupling agents, which are adsorbed on the surface of the photocatalyst particles to bond between the less degradable binder and the photocatalyst particles, so that the photocatalyst particles cannot be directly Contact with the adhesive, which makes the adhesive less decomposing.

Next, each sample of the sample AD of the present invention is placed in 3 liters of glassware, acetaldehyde is added as a malodorous component with a concentration of 90 ppm, and then the container is sealed. Expose the container to a mercury lamp with an ultraviolet intensity of 14mW/cm2 and irradiate the surface of each sample for 60 minutes. After irradiation, the concentration of acetaldehyde in the glassware was measured. The results are shown in Table 1. Due to the photocatalytic effect of titanium oxide, the sample AD can effectively decompose acetaldehyde.

Table 1 Sample Acetaldehyde Concentration (ppm) Example 1 A 0.5 Example 2 B 0.5 Example 3 C 30.0 Example 4 D 0.5 Example 5 Hydrolyzed by heating titanium oxysulfate (CS-N, available from Ishihara Sangyo Kaisha, Ltd.) The acidic titanium dioxide sol obtained is added with NaOH, the pH is adjusted to 7, filtered, washed, dried, and ground into titanium oxide. 0.2g of titanium oxide, 0.8g of white cement (available from OnodaCement Co., Ltd.) and 0.7g of water were mixed, coated on a glass plate with an area of 50cm2, and dried at room temperature to prepare the photocatalyst composite of the present invention ( Sample F). The titanium dioxide content of this sample F is 17V%, based on the total amount of titanium oxide and less degradable binder.

Example 6 is the same as Example 5, except that 0.8 g of DENCA high alumina cement (Hi, available from DENKI, KAGAKU KOGYO KK) is used instead of white cement, and the method is repeated to obtain the photocatalyst composite of the present invention (Sample G). The sample G has a titanium dioxide content of 17V%, based on the total amount of titanium oxide and less degradable binder.

In Comparative Example 2, 1.0 g of the same white cement as in Example 5 and 0.7 g of water were mixed, coated on a glass plate with a surface area of 50 cm 2, and dried to obtain sample H.

In Comparative Example 3, 1.0 g of the same DENCA high alumina cement as in Example 6 and 0.7 g of water were mixed, coated on a glass plate with a surface area of 50 cm 2, and dried to obtain Sample I.

Put each sample FI of the example and the comparative example in a 4l container, and inject standard nitrous oxide gas. Expose the container to black light rays with an ultraviolet intensity of 1mW/cm2 and irradiate the surface of each sample. A NOx sensor (11L, available from GASTEC Co. Ltd.) was used to detect the concentration of NOx gas in the glass container over time. The results are shown in Table 2. Samples F and G from Examples 5 and 6 greatly reduced the NOx concentration, while samples H and I of Comparative Examples 2 and 3 hardly changed the NOx concentration. From this, it was found that the photocatalyst of the present invention can effectively remove nitrous oxide through oxidation. In the above method, the cement weight of each of samples F and G was measured to evaluate the weight loss of cement. No weight loss was observed, indicating that the cement did not decompose.

Table 2

Example 7 All the coating compositions obtained by repeating the same method as Example 1 were coated on a transparent acrylic plate with a surface area of 100 cm 2 and dried at 120° C. for 20 minutes to prepare the photocatalyst composite of the present invention (Sample J). The sample J has a titanium dioxide content of 90V%, based on the total amount of titanium oxide and less degradable binder.

In Comparative Example 4, the same acrylic plate as in Example 7 was used as sample K.

The samples J and K of the above examples and comparative examples were placed on the inner wall of a 50 liter water bath. Add 45l of water and 20 goldfish (Wakin) to the bath, and illuminate the outside with the light of 2 20W fluorescent lamps.

After the goldfish were fed for 2 weeks, it was observed that the surface of sample K of Comparative Example 4 had algae deposited on the surface, while the surface of sample J of Example 7 did not see algae deposits. This is because even though the algae were deposited on the surface of sample J in Example 7, they were immediately decomposed by photocatalysis. In the above method, the weight loss of the fluorinated polymer in sample J was measured. No weight loss was seen, indicating that the fluorinated polymer was not decomposed.

Example 8 repeats the same method as Example 7, except that the mixture of the following ingredients is vibrated in a paint shaker for 1 hour to fully mix and disperse into a paint composition, and use a spin coater (1000r.pm x 10 sec) to make it They are all coated on a transparent acrylic plate. The plate has a first layer composed of a less degradable adhesive, but without any photocatalyst particles on the surface. The plate is used as a substrate to make the photocatalyst of the present invention. (Sample L). The titanium dioxide of this sample L, that is, the content of the photocatalyst particles is 90V%, based on the total amount of titanium oxide and the less degradable binder. Titanium oxide without photocatalysis (CR-90, available from Ishiharasangyo Kaisha, Ltd.) 3.3g fluorinated polymer (LUMIFRON LF200C, available from Asahi Glass Co., Ltd.) 5.5g isocyanate-based hardener 1.1g Toluene The 20.7 ml measurement of the weight loss of the binder used in the sample L in the above method revealed that the sample L of the present invention has no weight change, the binder has not degraded, and the titanium dioxide photocatalyst particles have not separated from the matrix. The film strength of Sample L of Example 8 is represented by pencil hardness as 3H, which means that the photocatalyst particles are firmly bonded. In addition, the sample L was placed in a water stream and irradiated with black light for 3 weeks, and the irradiation method was such that the surface ultraviolet intensity was 2mW/cm2. Nevertheless, no detachment of the titanium dioxide photocatalyst particles from the substrate was found.

Implementation 9

The same method as in Example 1 was repeated, except that titanium dioxide particles coated with a zinc compound were used instead of titanium oxide to prepare the photocatalyst composite of the present invention (Sample M). The content of the photocatalyst titanium dioxide particles coated with the zinc compound in this sample M is 90V% (based on the total amount of the photocatalyst particles and the less degradable binder).

The titanium dioxide particles coated with the zinc compound are prepared as follows: add water and NaOH to the titanium dioxide slurry obtained by heating and hydrolyzing titanium oxysulfate to make the slurry pH 10 and 100 g/l expressed by TiO2. In the autoclave, the slurry was subjected to hydrothermal treatment at 150°C for 5 hours, then neutralized with nitric acid, filtered, and washed with water. Water was added to the obtained titanium dioxide wet cake to prepare a slurry containing 100 g of TiO2/l. Then add hydrochloric acid to make the pH 4. Under stirring, 7.2 ml of 1 mol/l zinc chloride aqueous solution was added dropwise to 1 liter of the above slurry. Then neutralize it with 2N NaOH, filter, and wash with water. After that, the obtained product was dried at 120° C. for 16 hours, and ground into titanium dioxide particles carrying zinc compounds, in which the ratio of ZnO:TiO2 was 1:99.

Example 10 repeated the same method as Example 1, except that titanium dioxide particles coated with an iron compound were used instead of titanium oxide to prepare the photocatalyst composite of the present invention (Sample N). The content of the photocatalyst titanium dioxide particles coated with the iron compound in the sample N is 90V%, based on the total amount of the photocatalyst particles and the less degradable binder.

The preparation of titanium dioxide particles coated with iron compounds is as follows: the titanium dioxide obtained by heating and hydrolyzing 10 g of titanium oxysulfate is used to prepare a slurry of 100 g of TiO2/l. Add 2.9ml of ferric chloride (FeCl3.6H2) aqueous solution with a concentration of 5g/l to it, stir continuously for 1h, and then add dilute ammonia to adjust the pH to 7. After the slurry was stirred for 1 hour, it was filtered, washed with water, and dried at 110°C for 3 hours to become titanium dioxide particles coated with iron compounds.

The ratio of the iron compound supported on these titanium dioxide particles to Fe/TiO2 was 300 ppm.

Example 11 repeats the same method as Example 10, except that the concentration of the ferric chloride aqueous solution is 50 g/l to prepare the photocatalyst of the present invention (Sample O). The content of the photocatalyst titanium dioxide particles coated with the iron compound in the sample O was 90V%, based on the total amount of the photocatalyst particles and the less degradable binder.

The amount of iron compound supported by these titanium dioxide particles is Fe/TiO2 of 3000 ppm.

Example 12 The same method as Example 1 was repeated, except that 8.9 g of TiO2 and 0.5 g of activated carbon were used to prepare the photocatalyst composite of the present invention (Sample P). The total amount of titanium dioxide and activated carbon of sample P is 90V%, based on the total amount of titanium dioxide, activated carbon, and less degradable binder.

Example 13 repeats the same method as Example 12, except that 0.8 g of zeolite is used instead of activated carbon to prepare the photocatalyst composite of the present invention (Sample Q). The total amount of titanium dioxide and zeolite is 90% by volume, based on the total amount of titanium dioxide, zeolite and less degradable binder.

Observations of the less degraded adhesive of each sample in sample LQ showed that no weight loss was found. In other words, the less degraded binder of sample LQ was not degraded, and the titanium dioxide particles did not detach from the matrix.

Next, put the samples A, N, and O of the present invention in a 0.8l glass container, add acetaldehyde as a malodorous component with a concentration of 100 ppm, and then seal the container. After the container was placed for 30 minutes, the surface of each sample was irradiated with black light with an ultraviolet intensity of 1mW/cm2 for 60 minutes. After the irradiation, the concentration of acetaldehyde in the glass container was measured. The results are shown in Table 3. Due to the photocatalytic effect of titanium oxide, samples A, N, and O effectively decompose acetaldehyde.

Table 3 Samples Acetaldehyde concentration (ppm) Example 1 A 10.5 Example 10 N 2.0 Example 11 O 0.4 Then, samples M, P, and Q were placed in each 0.8l glass container. Add malodorous methyl mercaptan with a concentration of about 500 ppm, and seal the container. Place the container without any ultraviolet radiation for 2 hours, and then irradiate it with black light for 60 minutes in the same way. The ultraviolet intensity on each sample is 1mW/cm2. After irradiation, the concentration of methyl mercaptan in the container was measured. The results are shown in Table 4. It is clear from Table 4 that due to the effect of the photocatalyst particles of samples M, P, and Q, methyl mercaptan was effectively removed.

Table 4 Sample methyl mercaptan concentration (ppm) Example 9 M 72 cases 12 P 90 cases 13 Q 125 In the above detection process, when the container is not irradiated with ultraviolet rays and left for 2 hours, the concentration of methyl mercaptan in each sample container is 250 ppm . After placing the container for another 1 hour without ultraviolet radiation, the methyl mercaptan concentration in the sample M and Q containers was 240 ppm, and the sample P container was 220 ppm.

The photocatalyst composite of the present invention includes a matrix on which photocatalyst particles are bound by a less degradable binder, and hardly causes decomposition and degradation due to photocatalysis. The invention enables the photocatalyst particles to be firmly bonded to any substrate for a long time without damaging the photocatalytic effect. With the photocatalyst composite of the present invention, harmful substances, malodors, oily ingredients, bacteria, actinomycetes, fungi, algae, etc. can be effectively and quickly removed. Therefore, the photocatalyst composite is a very useful deodorant and disinfectant for household and industrial use. In addition, the photocatalyst composite of the present invention can be used for a long time, has a high degree of safety, is suitable for various harmful substances, and can be discharged without polluting the environment. So it is very useful in industry. In the method for preparing the photocatalyst composite according to the present invention, the fluorinated polymer is used as a less degradable binder, so that a preferred photocatalyst composite can be produced. The surface of the photocatalyst composite is weak due to the weak adhesion of the fluorinated polymer. It is not easy to absorb dust and pollutants.

The method for preparing the photocatalyst composite of the present invention is a useful method. The method can use any material such as plastic as a substrate to conveniently and easily prepare a photocatalyst composite of constant quality.

The coating composition of the present invention can be coated or sprayed on a substrate of any shape or its desired part, so that it is easy to exert a photocatalytic effect. So it is especially suitable for household applications.