film coated with photochemical active catalyst layer

Photocatalytic active film {film coated with photochemical active catalyst layer}

1 is an explanatory diagram of a photocatalytic action;

Figure 2 is an edible oil decomposition test table on the photocatalytic active film

3 is a break strength measurement table of the photocatalytic active film;

<background-art><p> The present invention relates to a photocatalytically active film (film). More particularly, it relates to a film having photocatalytic activity by coating a photocatalyst such as titanium dioxide (titanium oxide or titania), zirconium oxide, arsenic oxide, zinc oxide, tin oxide or cerium oxide.</p><p> The material used as a photocatalyst is a semiconducting metal oxide, which absorbs bandgap energy of 3.2 eV or more or 400 nm or less to form electron hole pairs, and the excited holes react with moisture by strong oxidizing power to generate OH radicals. decomposes organic matter.</p><p> M + hυ M + e^- + h⁺ (1)</p><p> MH₂O + h⁺ M-OH + O· (2)</p><p> M-OH + h⁺ M + OH· (3)</p><p> The generation energy of the OH radical is equivalent to 120 Kcal/mol, and is larger than the various binding energies of the CC bond, CH bond, CN bond, CO bond, OH bond, and NH bond of organic compounds. It is widely used for removal and sterilization of contaminants, harmful substances or germs, etc.</p><p> In order to take advantage of the strong oxidizing action of the photocatalyst, titanium dioxide is mixed with the tile to give it antibacterial properties, thereby producing tiles having a strong sterilization effect and discoloration resistance. There is a case in which the maintenance cost is reduced by applying the automatic purification function by the decomposition power of titanium dioxide to lighting such as street lamps. Photocatalysts can also be applied to air pollution treatment or wastewater treatment. Since the reaction structure is simple and strong effect can be obtained, it can be an innovative technology if only the efficiency is improved (On titanium oxide photocatalyst, Siemushi time, 1998). It can also be used to enhance the cleaning effect of the material surface by using the superhydrophilicity caused by the water adsorption reaction.</p><p> Various materials for supporting the photocatalyst have been proposed. A photocatalyst is deposited on the surface of ceramics or inorganic fibers such as glass and tiles, applied by a sol-gel method, and then coated by a baking treatment or a chemical vapor deposition (CVD) method. There is an example in which paper having the effect of preventing pollution or removing odors by mixing a photocatalyst in pulp is produced. However, in addition to the above inorganic materials, various attempts have been made to apply titanium dioxide to plastics that account for 90% of household products.</p><p> As a method of coating the photocatalyst on the substrate, a film can be formed at a relatively low temperature by vacuum treatment by CVD, ion plating, or sputtering. However, such an apparatus requires expensive equipment having a vacuum, and it is impossible to form a thin film on a large-area substrate or to form a homogeneous thin film on a complex substrate surface.</p><p> As a simple method, the photocatalyst can be coated by making an alkoxide photocatalyst sol, applying the sol phase by dipping, spin coating or spraying the coating agent, and baking at a temperature of several hundred degrees. Coating by the sol-gel method is generally 300 to 400<b>℃</b>It is not at a satisfactory level because it requires a baking temperature of Attempts to lower the temperature of baking are being made extensively, but 200<b>℃</b>is the minimum temperature. </p><p> More than 90% of household items used today are made of plastics, and many are being replaced by plastics as structural materials. Therefore, if the photocatalyst can be effectively applied on plastic, it can be applied to various fields. It can be applied to air purifiers, ventilation fans, fans, vacuum cleaners, clothes dryers, dish dryers, dish washing machines, kitchen waste, etc. to achieve the effects of pollution prevention, microbial growth prevention and odor removal (Patent Publication 1998-087179). but 200<b>℃</b>The baking temperature of most corresponds to the deformation temperature of plastics. Therefore, the application of this method to plastics is limited.</p><p> The effect on acetaldehyde decomposition and discoloration resistance was demonstrated by mixing titanium dioxide powder into the pulp slurry to make paper, but the burst strength of the paper decreased with the use time (p120 for titanium oxide photocatalyst, Siemushi time) , 1998 Japan). A structural exterior material that does not require maintenance by mixing and molding a photocatalyst powder into a fluororesin powder with strong chemical resistance has been proposed (Japanese Patent Application Laid-Open No. 6-365614). Although the fluororesin is stable in photocatalytic activity, the photocatalytic activity is inefficient because of its high price and the high rate of titanium dioxide being impregnated in the resin.</p><p> There are several problems to be solved in supporting photocatalysts on plastics.</p><p> a) The photocatalyst should adhere well to the base.</p><p> b) the photocatalyst should not be impregnated on the substrate, so that the photocatalytic activity should not be reduced, as well as</p><p> c) The matrix should not be degraded by decomposition due to photocatalytic activity.</p><p> d) The baking temperature should be less than the heat deflection temperature of the plastic film.</p></background-art><tech><p> The present invention provides a photocatalytic active film having excellent bonding strength between the film and the coating film and excellent photocatalytic activity that is not deteriorated by photocatalytic chemical reaction by coating a protective layer on one surface of a plastic substrate film and forming a film thereon after drying, and a method for producing the same is to provide Another object of the present invention is to prepare an economical photocatalytically active film that can be stamped on household products.</p></tech>

<p> by the present invention</p><p>1) preparing a plastic base film;</p><p>2) laminating a protective layer containing a silicone resin as a main component on the film to a thickness of 1 to 10 μm and drying;</p><p>3) applying a catalyst dispersion in a silica sol with a photocatalyst oxide dispersed in a molar ratio of 1/10 to 10 to silica on the film of step 2) in a thickness of 0.5 to 20 μm;</p><p>4) Remove the film from step 3) to 100<b>℃</b> Pre-drying at a temperature below; and</p><p>5) There is provided a method for producing a photocatalytic active film comprising the step of baking the pretreated film at 110° C. or higher in a range in which the base film does not deform.</p><p> Also according to the present invention</p><p>1) Deformation temperature 110<b>℃ </b>more than a paper or plastic base film;</p><p>2) a silicon resin layer laminated on the film to a thickness of 1 to 10 μm;</p><p>3) a catalyst dispersion layer in which the photocatalyst oxide is dispersed in a molar ratio of 1/10 to 10 to silica in the silica sol coated in 0.5 to 20 μm on the resin layer, and the layer is baked at a temperature of 110° C. or higher and a photocatalytic active film bonded to the silicon resin layer is provided.</p><p> Deformation temperature 110<b>℃</b> The above plastic film is a general-purpose plastic, and nylon, acrylic, polyester, polyacetal, and copolymer films thereof may be used. The nylon is preferably an aromatic nylon 6 or nylon 6.6 copolymer. Acrylic is a polyacrylic acid resin derivative and polyester is preferably polyethylene teretalate. Polyphenylene sulfide, polyphenylene oxide, polyether imide, etc. may be used as a high heat-resistance resin film.</p><p> The material used for the adhesive layer was a silicon-modified resin containing 2-60% by weight of silicon; or a resin containing 3-60% by weight of polysiloxane. The resin is suitable for strongly adhering the photocatalyst and protecting the carrier from the photocatalyst. When using an acrylic-silicon resin containing less than 2% by weight of silicon and a resin containing less than 3% by weight of polysiloxane, the adhesion of the photocatalyst layer is poor due to the weakening of the adhesive layer by the photocatalyst and is easily peeled off. If a silicon-modified resin containing 60% by weight or more of silicon in the acrylic silicon resin is added, the adhesive strength between the adhesive layer and the carrier is poor because of the low adhesive strength of the adhesive layer, and the abrasion resistance is poor.</p><p> The silicon-modified resin used for the adhesive layer is preferably an acrylic-silicon resin, an epoxy-silicon resin or a polyester-silicon resin. The silicon-modified resin can introduce silicon into the resin by various methods such as transesterification reaction, graft reaction using silicon polymer or reactive silicon monomer, hydroxylation reaction, and block copolymerization. Any silicon-modified resin obtained by any of the above methods can be used as the adhesive layer resin. Among the silicon-modified resins, acrylic, epoxy, and polyester resins are most suitable from the viewpoint of film formation, toughness and adhesion properties with the carrier. The resin can be used by dissolving it in any form of a solvent or emulsion.</p><p> Preferred polysiloxanes are hydrolysates of silicon alkoxides having alkoxy having 1-5 carbon atoms or products prepared from such hydrolysates. Polysiloxanes obtained by hydrolyzing silicon alkoxide polysiloxanes containing partially chlorine can be used. As a result of using polysiloxane containing a large amount of chlorine, the carrier is corroded or has poor adhesion due to impure chlorine ions.</p><p> A preferred polysiloxane compound is a polycondensate of a silicon alkoxide represented by the following formula (1). </p><p>Formula (1) SiCl_a(OH)_bR_c(OR')_d</p><p>(wherein R is amino, carboxyl, or alkyl having 1-8 carbon atoms which may be substituted with chlorine or alkoxy having 1-8 carbon atoms, which may be substituted with alkyl of 1-8 carbon atoms, and R' is alkyl having 1-8 carbon atoms. and a, b and c are 0, 1 or 2, d is an integer of 2-4, and a + b + c + d = 4.)</p><p> There are various methods for incorporating polysiloxane into the resin. For example, a product of partially hydrolyzed silicon alkoxide is mixed with a resin in advance and hydrolyzed with moisture in air when an adhesive layer is formed. Any method capable of uniformly mixing the resin may be used. A small amount of acid or base catalyst can be added to change the hydrolysis rate of the silicon alkoxide. It is preferable to add 3-60% by weight of polysiloxane to the resin to strongly adhere the photocatalyst layer on the carrier. An amount of 3-40% by weight is particularly preferred for improving alkali resistance. The polysiloxane can be incorporated into any resin such as acrylic resins, acrylic-silicon resins, epoxy-silicon resins, polyester-silicon resins, silicon-modified resins, urethane resins, epoxy resins, polyester resins and alkyd resins. Silicon-modified resins comprising acrylic-silicon resins, epoxy-silicon resins, polyester-silicon resins, and mixtures of these resins are preferable from the viewpoints of durability and alkali resistance.</p><p> In order to obtain a catalyst dispersion, first, the molar ratio of silica photocatalyst to silica gel is in the range of 1/10 to 10 TiO₂Add powder and mix. In a method of coating the mixed photocatalyst dispersion with an appropriate thickness on the film, immersing the film wound on the drum in the resin containing the photocatalyst dispersion, or coating with roller coating, knife coating, etc. In order to obtain a uniform thickness, desirable. Coating and drying may be repeated to obtain a coating layer of a desired thickness.</p><p> 100 film coated with photocatalyst<b>℃</b> Pre-drying at a lower temperature. 110 pre-dried film<b>℃ </b>more than 130<b>℃ </b>The silica is baked at the following temperature. At this time, it is very important to select a temperature at which the base film is not deformed as the baking treatment temperature. In order to prevent deformation of the base film, it is sometimes desirable to compress the coated film with a roll heated to a baking temperature. At this time, in order to prevent thermal deformation of the base film, a temperature lower than the catalyst layer baking temperature may be selected for the roll in contact with the base film.</p><p> Thereby, not only the catalyst layer is firmly bonded to the substrate by the silicone resin, but the photocatalytic activity is maintained as a structure in which titanium oxide is supported on porous silica, and the substrate is blocked and protected from the photocatalyst by the silicone resin, thereby preventing the deterioration of the substrate. and various substrates can be used as the photocatalytic active film.</p><p> Hereinafter, the present invention will be described by way of Examples. The scope of the present invention is not limited by these examples.</p><p>Example 1</p><p> A polyester film of 5 cm in width and length of 0.02 mm thick was prepared as a base film. Polyethoxy siloxane was applied to a thickness of 5 μm on the film and dried at room temperature for 10 hours. Titanium dioxide powder having a diameter of 100 nm was mixed and dispersed in silica sol. The catalyst layer was immersed in the catalyst dispersant so that the adhesive layer of the film was applied to a thickness of 5 μm and dried at room temperature for 2 hours.<b>℃</b>pre-dried with 110 of the laminated film<b>℃</b>It was pressed several times with a hot plate heated with a furnace.</p><p>Example 2</p><p> A photocatalyst coating film was prepared in the same manner as in Example 1, except for mixing the silica sol with a molar ratio of silica:titanium oxide to 1:5 when preparing the photocatalyst dispersant.</p><p>Example 3</p><p> 5 cm in width and length, respectively, and 0.03 mm thick white paper was prepared as a base film. An acrylic-modified silicone resin was applied to a thickness of 5 μm and dried at room temperature for 10 hours. Hereinafter, titanium dioxide was supported in the same manner as in Example 1.</p><p>Example 4</p><p> A photocatalyst coating film was prepared in the same manner as in Example 3, except for mixing the silica sol with a molar ratio of silica:titanium oxide to 1:5 when preparing the photocatalyst dispersant.</p><p>Control Example 1</p><p> An untreated 5 cm thick 0.02 mm polyester film was prepared as a base film, respectively. </p><p>Control Example 2</p><p> A polyester film of 5 cm in width and length of 0.02 mm thick was prepared as a base film. An adhesive mixture in which a titanium dioxide sol having a diameter of 100 nm is mixed and dispersed on the film was coated to a thickness of 10 μm, and after drying at room temperature for 2 hours, 70<b>℃</b>dried with </p><p>Control Example 3</p><p> A photocatalyst coated white paper was prepared in the same manner as in Control Example 1, except that white paper was used instead of the polyester film.</p><p>Test Example 1</p><p> Examples 1 to 4, each of the samples of Control Examples 1 to 3, cooking oil 0.1 mg / cm<b>²</b> coated with 25<b>℃</b>UV at room temperature of 1 mW/cm² It was irradiated with intensity and the amount of edible oil reduction per hour of light irradiation was investigated. In Control Example 1, no appreciable decrease in edible oil was found. Compared with Control Examples 2 and 3, Examples 1 to 4 showed a significant decrease in the amount of edible oil. The results are shown in FIG. 2 .</p><p>Test Example 2</p><p> It was carried out for a long time under the same conditions as in Test Example 1 to measure the rupture strength of the substrate.</p><p>In the case of Control Example 1, a decrease in the breaking strength was not detected, and in Examples 1 to 4, a slight decrease in the breaking strength was achieved. In the case of Control Examples 2 and 3, the reduction in the breaking strength of the substrate was remarkable.</p><p> The results are shown in FIG. 3 . </p>

<p> According to the present invention, the catalyst layer is tightly bound to the substrate by the silicone resin, and the titanium oxide is supported on the porous silica, so that the photocatalytic activity is maintained and the substrate is blocked and protected from the photocatalyst by the silicone resin, thereby preventing the deterioration of the substrate. and various substrates can be used as the photocatalytically active film. According to the present invention, it is possible to obtain a film with high photocatalytic activity without being deteriorated by ultraviolet rays, and this film itself can be economically obtained as a photocatalytically active film that can be used variously as a surface heat-sealing film for interior and exterior buildings and household goods. have.</p>