Photocatalytic particle-containing resin composition and method for producing photocatalytic particle-containing resin composition

Abstract

To suppress embedding of photocatalytic particles in a raw material.SOLUTION: A method for producing a photocatalytic particle-containing resin composition (100) according to the present invention comprises: a step of dispersing, in a resin (10r), a photocatalytic foaming agent composite (20F) in which photocatalytic particles (20) and foaming agent particles (F) are combined; and a step of foaming the foaming agent particles (F) within the resin (10r).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photocatalyst particle-containing resin composition and a method for producing the photocatalyst particle-containing resin composition. [Background technology]

[0002] Photocatalysts have a catalytic action that mainly efficiently decomposes organic substances, and are suitable for use in decomposing volatile organic compounds (VOCs), for example.

[0003] Effective utilization of such photocatalysts has been studied (see Patent Document 1). Patent Document 1 describes a foaming material in which titanium oxide as a photocatalyst, calcium carbonate as a foaming agent, and glass bottle powder as a raw material are mixed and baked to expose the photocatalyst at the foamed portion of the foaming agent. The foaming material of Patent Document 1 is intended to exhibit photocatalytic activity inexpensively and efficiently. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-117926 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even in the foam material of Patent Document 1, if the photocatalyst is not present in the area where the foaming agent is foamed, the photocatalyst may be buried in the raw material, and the photocatalytic activity may not be fully exhibited.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a photocatalyst particle-containing resin composition that can prevent photocatalyst particles from becoming buried, and a method for producing a photocatalyst particle-containing resin composition. [Means for solving the problem]

[0007] The method for producing a photocatalyst particle-containing resin composition according to the present invention includes the steps of dispersing a photocatalyst blowing agent composite, which is a composite of photocatalyst particles and blowing agent particles, in a resin, and foaming the blowing agent particles in the resin.

[0008] The method for producing a photocatalyst particle-containing resin composition according to the present invention includes the steps of dispersing a photocatalyst foaming assistant composite, which is a composite of photocatalyst particles and foaming assistant particles, and foaming agent particles in a resin, and foaming the foaming agent particles in the resin.

[0009] The photocatalyst particle-containing resin composition according to the present invention comprises a photocatalyst-blowing agent composite in which photocatalyst particles and blowing agent particles are combined, and a resin in which the photocatalyst-blowing agent composite is dispersed.

[0010] The photocatalyst particle-containing resin composition according to the present invention comprises a photocatalyst foaming assistant composite in which photocatalyst particles and foaming assistant particles are combined, foaming agent particles, and a resin in which the photocatalyst foaming assistant composite and the foaming agent particles are dispersed.

[0011] The photocatalyst particle-containing resin composition according to the present invention comprises a porous resin having a plurality of pores and photocatalyst particles dispersed in the porous resin, and the density of the photocatalyst particles decreases from the surface of the pores toward the interior of the porous resin. [Effects of the Invention]

[0012] According to the present invention, it is possible to prevent the photocatalyst particles from being buried. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of a portion of FIG. [Figure 3] FIG. 2 is a flow diagram illustrating a method for producing a photocatalyst particle-containing resin composition according to the present embodiment. [Figure 4A]1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 4B] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 4C] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 5A] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 5B] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 5C] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 6] FIG. 2 is a flow diagram illustrating a method for producing a photocatalyst particle-containing resin composition according to the present embodiment. [Figure 7A] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 7B] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 7C] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 8A] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 8B] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. [Figure 8C] 1A to 1C are schematic diagrams illustrating a method for producing a photocatalyst particle-containing resin composition according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of a photocatalyst particle-containing resin and a method for producing a photocatalyst particle-containing resin according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters, and description thereof will not be repeated.

[0015] First, a photocatalyst particle-containing resin composition 100 of this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of the photocatalyst particle-containing resin composition 100.

[0016] 1, the photocatalyst particle-containing resin composition 100 includes a porous resin 10 and photocatalyst particles 20. The porous resin 10 has a plurality of pores 10h. The photocatalyst particles 20 are dispersed in the porous resin 10.

[0017] [Porous Resin 10] A plurality of pores 10h are provided in the porous resin 10. The pores 10h are formed by foaming of a foaming agent in the porous resin 10. The foaming agent present in the resin is gasified by foaming and disappears to the outside.

[0018] In the porous resin 10, at least some of the pores 10h may be in communication with the outside of the porous resin 10. Alternatively, the pores 10h may be located within the porous resin 10 without being in communication with the outside of the porous resin 10.

[0019] The porous resin 10 is a thermoplastic resin. Typical materials for the porous resin 10 include polystyrene, polyolefin (e.g., polyethylene, polypropylene), vinyl chloride, and ABS (acrylonitrile, butadiene, and styrene).

[0020] In the porous resin 10, the plurality of pores 10h are randomly positioned. The sizes of the plurality of pores 10h are also randomly distributed within a certain range. The pores 10h may be in contact with adjacent pores 10h, so that some of the pores 10h are connected to each other. Some of the pores 10h may be positioned on the outer surface of the porous resin 10.

[0021] [Photocatalyst particles 20] The photocatalyst particles 20 have a photocatalytic effect. When irradiated with light, the photocatalyst particles 20 exhibit a catalytic effect. The photocatalyst particles 20 have an oxidative decomposition function. The photocatalyst particles 20 can remove volatile organic compounds (VOCs) through their catalytic effect.

[0022] The photocatalyst particles 20 are dispersed in the porous resin 10. The photocatalyst particles 20 are located on the surfaces of the pores 10h of the porous resin 10. Ideally, at least one photocatalyst particle 20 is located on the surface of the pores 10h of the porous resin 10. Furthermore, a portion of the photocatalyst particle 20 is located buried within the porous resin 10.

[0023] Materials for the photocatalytic particles 20 include titanium oxide (TiO2) and tungsten oxide (WO3).

[0024] The particle size of the photocatalyst particles 20 is smaller than the particle size of the pores 10h of the porous resin 10. The particle size (D50) of the photocatalyst particles 20 is preferably 1 nm or more and 500 nm or less, and may be 5 nm or more and 200 nm or less. When the particle size of the photocatalyst particles 20 is 5 nm or more, aggregation of the photocatalyst particles 20 can be reduced and the photocatalyst particles 20 can be easily redispersed. When the particle size of the photocatalyst particles 20 is 200 nm or less, the photocatalyst particles 20 can be easily mixed uniformly with other components during processing and separation can be suppressed. The particle size of the photocatalyst particles 20 can be measured using a BET specific surface area meter, a laser diffraction particle size distribution meter, a dynamic light scattering particle size distribution meter, etc.

[0025] The photocatalyst particles 20 may contain tungsten oxide. When the photocatalyst particles 20 contain tungsten oxide, a catalytic reaction caused by light absorption can be carried out using a material that is relatively easy to obtain.

[0026] The photocatalyst particle-containing resin composition 100 of this embodiment can be used in a variety of applications. When the porous resin 10 is polystyrene, the photocatalyst particle-containing resin composition 100 has high heat insulating performance. For this reason, the photocatalyst particle-containing resin composition 100 is used as a heat insulating material in buildings and houses, food trays, etc.

[0027] When the porous resin 10 is polyethylene, the photocatalyst particle-containing resin composition 100 has excellent chemical resistance and impact resistance, and is therefore suitable for use as a heat insulating waterproof sheet, a cushioning material, and a packaging material.

[0028] When the porous resin 10 is polypropylene, the photocatalyst particle-containing resin composition 100 is lightweight and has excellent processability, and is therefore suitable for use as automobile parts and packaging materials.

[0029] When the porous resin 10 is vinyl chloride, the photocatalyst particle-containing resin composition 100 has excellent weather resistance, chemical resistance, and self-extinguishing properties. The photocatalyst particle-containing resin composition 100 is suitable for use in heat insulation materials, sealants, wallpaper, etc.

[0030] As described above, in the photocatalyst particle-containing resin composition 100, the photocatalyst particles 20 are located on the surfaces of the plurality of pores 10h of the porous resin 10. Typically, at least one photocatalyst particle 20 is located in one pore 10h of the porous resin 10. Furthermore, the larger the size of the pores 10h in the porous resin 10, the greater the number of photocatalyst particles 20 located in the pores 10h.

[0031] Furthermore, the photocatalyst particles 20 are also located inside the porous resin 10. In this manner, the photocatalyst particles 20 are dispersed in the porous resin 10. However, the photocatalyst particles 20 are distributed in the pores 10h of the porous resin 10 and in the vicinity of the pores 10h at a higher density than inside the porous resin 10.

[0032] In the photocatalyst particle-containing resin composition 100, the photocatalyst particles 20 are dispersed in the porous resin 10, but co-catalyst particles may be dispersed in the porous resin 10 in addition to the photocatalyst particles 20. Typically, the co-catalyst particles are supported on the photocatalyst particles 20 before being dispersed in the porous resin 10. The co-catalyst particles are dispersed in the porous resin 10 while being supported on the photocatalyst particles 20. The co-catalyst particles can reduce the energy gap of the photocatalyst particles 20 and increase their responsiveness in the visible light region. For example, platinum group metals (e.g., Pt, Pd, Rh, Ru, Os, and Ir) can be used as the material for the co-catalyst particles.

[0033] In the porous resin 10, some of the pores 10h are located on the outer surface of the porous resin 10, so that the photocatalyst particles 20 located on the surfaces of the pores 10h can suitably decompose organic matter (e.g., VOC gases) outside the photocatalyst particle-containing resin composition 100. However, even if some of the pores 10h are located inside the porous resin 10, the photocatalyst particles 20 located on the surfaces of the pores 10h can suitably decompose organic matter (e.g., VOC gases) generated from the porous resin 10 itself.

[0034] Next, a photocatalyst particle-containing resin composition 100 of this embodiment will be described with reference to Figures 1 and 2. Figure 2 is a partially enlarged view of the photocatalyst particle-containing resin composition 100.

[0035] As shown in Fig. 2, the photocatalyst particles 20 are dispersed in the porous resin 10. The photocatalyst particles 20 are present at a high density on the surfaces of the pores 10h of the porous resin 10. The density of the photocatalyst particles 20 decreases as one moves from the pores 10h to the inside of the porous resin 10.

[0036] The photocatalyst particle-containing resin composition 100m of this embodiment comprises a porous resin 10 having a plurality of pores 10h, and photocatalyst particles 20 dispersed in the porous resin 10. The density of the photocatalyst particles 20 decreases from the surface of the pores 10h toward the inside of the porous resin 10. This allows the photocatalyst particles 20 to be effectively arranged on the surface of the pores 10h formed in the porous resin 10, thereby improving the photocatalytic efficiency.

[0037] Next, a method for producing the photocatalyst particle-containing resin composition 100 of this embodiment will be described with reference to Figures 1 to 3. Figure 3 is a flow diagram for explaining the method for producing the photocatalyst particle-containing resin composition 100.

[0038] 3, in step S102, a photocatalyst blowing agent composite obtained by combining photocatalyst particles 20 and blowing agent particles is dispersed in resin. First, a photocatalyst blowing agent composite obtained by combining photocatalyst particles 20 and blowing agent particles is produced. Next, the photocatalyst blowing agent composite is mixed with resin.

[0039] The photocatalyst-blowing agent composite can be produced by combining photocatalyst particles 20 with blowing agent particles. In the photocatalyst-blowing agent composite, the photocatalyst particles 20 have a photocatalytic function, and the blowing agent particles have a foaming function.

[0040] [Foaming agent particles] The foaming agent particles are gasified by heating. When the foaming agent particles are dispersed in the resin and heated, the foaming agent particles expand within the resin. The expansion of the foaming agent particles forms multiple pores 10h in the porous resin 10.

[0041] The foaming agent particles generate gas that becomes bubbles during foam molding, and may be either a chemical foaming agent or a physical foaming agent.

[0042] Examples of the physical foaming agent include chlorofluorocarbons, hydrocarbons, nitrogen, and carbon dioxide gases. In this case, the foaming agent particles may be capsule-shaped particles surrounding the gas dispersed in the resin.

[0043] Chemical blowing agents can be classified into organic and inorganic. Organic chemical blowing agents include azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DPT), and p,p'-oxybisbenzenesulfonylhydrazide (OBSH). Organic blowing agent particles mainly produce nitrogen gas.

[0044] An example of an inorganic chemical foaming agent is bicarbonate. Inorganic foaming agent particles mainly produce carbon dioxide gas. For example, sodium bicarbonate (sodium bicarbonate) is an example of a foaming agent particle. In this case, the foaming temperature (decomposition temperature) is between 140°C and 170°C.

[0045] [Photocatalytic blowing agent complex] The photocatalyst blowing agent composite is produced by combining photocatalyst particles 20 with blowing agent particles. For example, in the photocatalyst blowing agent composite, the photocatalyst particles 20 and the blowing agent particles are in close contact with each other.

[0046] [Production of photocatalytic blowing agent composite] The photocatalyst blowing agent composite is produced by mixing photocatalyst particles and blowing agent particles. The photocatalyst blowing agent composite may be produced by mixing the photocatalyst particles 20 and the blowing agent particles in a room temperature environment. For example, the photocatalyst blowing agent composite may be produced by mixing the photocatalyst particles 20 and the blowing agent particles while heating them.

[0047] Alternatively, the photocatalyst blowing agent composite may be produced by mixing the photocatalyst particles 20 and the blowing agent particles in a solvent. In this case, the solvent may be evaporated to produce a photocatalyst blowing agent composite in which the photocatalyst particles 20 and the blowing agent particles are in close contact with each other. At least one of the photocatalyst particles 20 and the blowing agent particles may be dissolved in the solvent. The evaporation of the solvent can improve the adhesion between the photocatalyst particles 20 and the blowing agent particles in the photocatalyst blowing agent composite.

[0048] As described above, a photocatalyst-blowing agent composite is produced in which the photocatalyst particles and the blowing agent particles are combined, and the photocatalyst-blowing agent composite is mixed with a resin, thereby dispersing the photocatalyst-blowing agent composite in the resin.

[0049] In step S104, the foaming agent particles are foamed in the resin, for example, by heating the resin, so that the foaming agent particles of the photocatalyst-foaming agent composite foam in the resin.

[0050] The foaming of the foaming agent particles in the resin produces a porous resin 10 with a plurality of pores 10h formed therein. This produces a photocatalyst particle-containing resin composition 100. Because the plurality of pores 10h are formed by the foaming agent particles of the photocatalyst foaming agent composite, photocatalyst particles 20 of the photocatalyst foaming agent composite are located in the plurality of pores 10h.

[0051] According to this embodiment, by foaming the foaming agent particles of the photocatalyst foaming agent composite in the resin, pores 10h are formed in the porous resin 10 near the photocatalyst particles 20, and the photocatalyst particles 20 can be effectively positioned on the surfaces of the pores 10h, thereby improving the photocatalytic efficiency.

[0052] In this way, by expanding the foaming agent particles of the photocatalyst blowing agent composite, which is a composite of photocatalyst particles 20 and foaming agent particles, the photocatalyst particles 20 are efficiently located on the surfaces of the pores 10h formed by the expansion of the foaming agent particles. This prevents the photocatalyst particles 20 from being buried in the porous resin 10. Furthermore, by forming multiple pores 10h in the porous resin 10 by the expansion of the foaming agent particles, the porous resin 10 exhibits a high specific surface area. Because the photocatalyst particles 20 are densely located in the multiple pores 10h of such porous resin 10, a higher photocatalytic function can be achieved than when the photocatalyst particles 20 are simply kneaded into the resin.

[0053] As described above, the method for producing the photocatalyst particle-containing resin composition 100 of this embodiment includes the steps of dispersing a photocatalyst blowing agent composite, which is a composite of photocatalyst particles 20 and blowing agent particles, in a resin, and expanding the blowing agent particles in the resin. By expanding the blowing agent particles of the photocatalyst blowing agent composite in the resin in this way, the photocatalyst particles 20 can be effectively positioned on the surfaces of the pores 10h formed in the porous resin 10 by the expansion of the blowing agent particles, thereby improving the photocatalytic efficiency.

[0054] Next, a method for producing the photocatalyst particle-containing resin composition 100 of this embodiment will be described with reference to Figures 1 to 5C. Figures 4A to 5C are schematic diagrams for explaining the method for producing the photocatalyst particle-containing resin composition 100.

[0055] As shown in Fig. 4A, photocatalyst particles 20 and foaming agent particles F are prepared. Typically, the particle size of the photocatalyst particles 20 is smaller than the particle size of the foaming agent particles F. Here, the photocatalyst particles 20 are contained in a container C1, and the foaming agent particles F are contained in a container C2.

[0056] For example, the material of the photocatalyst particles 20 includes tungsten oxide and titanium oxide.

[0057] For example, bicarbonates can be used as materials for the foaming agent particles F. Among bicarbonates, sodium bicarbonate is preferred. Sodium bicarbonate not only has a low decomposition temperature but also has relatively high storage stability. Furthermore, the decomposition products of sodium bicarbonate exhibit low toxicity.

[0058] As shown in FIG. 4B, photocatalyst particles 20 and foaming agent particles F are added to a solvent Sb. The solvent Sb is contained in a container C3. The solvent Sb may be neutral. For example, the solvent Sb is water. Alternatively, the solvent Sb may be acidic.

[0059] To the solvent Sb in the container C3, the photocatalyst particles 20 are added from the container C1, and the foaming agent particles F are added from the container C2.

[0060] For example, the photocatalyst particles 20 are added to the solvent Sb, and then the blowing agent particles F are added to the solvent Sb. Typically, after the photocatalyst particles 20 are added, the photocatalyst particles 20 are dispersed in the solvent Sb using a disperser. For example, an ultrasonic disperser, a colloid mill, a bead mill, or the like may be used as the disperser.

[0061] Thereafter, the blowing agent particles F are added to the solvent Sb. The blowing agent particles F may be added while the solvent Sb is being stirred with a liquid mixer. The stirring blades of the liquid mixer can mix the photocatalyst particles 20 and the blowing agent particles F more uniformly. If necessary, a dispersant may be added.

[0062] Alternatively, the foaming agent particles F may be added to the solvent Sb first, and then the photocatalyst particles 20 may be added to the solvent Sb. Alternatively, the foaming agent particles F may be added to another solvent and then added to the solvent Sb. Similarly, the photocatalyst particles 20 may be added to another solvent and then added to the solvent Sb.

[0063] At least one of the photocatalyst particles 20 and the blowing agent particles F is preferably soluble in the solvent Sb. For example, when the blowing agent particles F contain sodium bicarbonate, the sodium bicarbonate is water-soluble and dissolves in water as the solvent Sb.

[0064] When the solvent Sb is water and the photocatalyst particles 20 are tungsten oxide or titanium oxide, the photocatalyst particles 20 are dispersed in water. When the solvent Sb is water and the blowing agent particles F are sodium bicarbonate, the blowing agent particles F are dissolved in water. Therefore, when tungsten oxide or titanium oxide is added as the photocatalyst particles 20 to the water of the solvent Sb and sodium bicarbonate is added as the blowing agent particles F, the tungsten oxide or titanium oxide is dispersed in the water.

[0065] 4C, by evaporating the solvent Sb, a photocatalyst blowing agent composite 20F is produced, in which the photocatalyst particles 20 and the blowing agent particles F are combined. In the container C3, the particulate photocatalyst blowing agent composite 20F is produced. The solvent Sb may also be vaporized by heating.

[0066] In the photocatalyst blowing agent composite 20F, the components of the blowing agent particles F dissolved in the solvent Sb appear on the surfaces of the photocatalyst particles 20 that were not dissolved in the solvent Sb. In the photocatalyst blowing agent composite 20F, the surfaces of the photocatalyst particles 20 are covered with the components of the blowing agent particles F. In this way, the photocatalyst blowing agent composite 20F is produced.

[0067] The photocatalyst blowing agent complex 20F may be further pulverized into powder using, for example, an FM mixer or a jet mill.

[0068] As shown in Fig. 5A, the photocatalyst blowing agent complex 20F and the resin 10p are mixed. Here, the photocatalyst blowing agent complex 20F is added from a container C3 to a resin molding apparatus, and the resin 10p is added from a container C4. Typically, the photocatalyst blowing agent complex 20F is in particulate form, and the resin 10p is in pellet or particulate form.

[0069] In a resin molding apparatus, the photocatalyst blowing agent composite 20F and the resin 10p are mixed. The mixture of the photocatalyst blowing agent composite 20F and the resin 10p is preferably mechanically stirred. The resin 10p is melted and molded in the resin molding apparatus. Typically, the molding temperature of the resin 10p is set to a temperature lower than the foaming temperature of the blowing agent particles F. The photocatalyst blowing agent composite 20F is dispersed in the resin in which the resin 10p is dissolved.

[0070] Here, the resin molding device produces a film-like molded product, but the resin molding device may also produce a master batch.

[0071] 5B, a photocatalyst particle-containing resin composition 100m, which is a mixture of a photocatalyst blowing agent composite 20F and a resin 10r, is formed into a film. The photocatalyst particle-containing resin composition 100m includes the resin 10r and the photocatalyst blowing agent composite 20F, which is a composite of photocatalyst particles 20 and blowing agent particles F. Here, the photocatalyst blowing agent composite 20F is dispersed within the resin 10r.

[0072] As shown in FIG. 5C , by heating the photocatalyst particle-containing resin composition 100m, a photocatalyst particle-containing resin composition 100 is produced in which the photocatalyst particles 20 are densely dispersed in the pores 10h in the porous resin 10. More specifically, upon heating, the foaming agent particles F of the photocatalyst blowing agent composite 20F foam, thereby forming the pores 10h in the porous resin 10. At this time, the pores 10h in the porous resin 10 are formed in the vicinity of the photocatalyst particles 20, so that the photocatalyst particles 20 are effectively positioned on the surfaces of the pores 10h. Note that the photocatalyst particle-containing resin composition 100 may contain some photocatalyst blowing agent composite 20F in which the foaming agent particles F have not foamed.

[0073] According to this embodiment, the photocatalyst particles 20 are effectively positioned in the pores 10h in the porous resin 10, and therefore the photocatalyst particles 20 can be prevented from being buried in the resin 100.

[0074] This embodiment also includes a step of adding photocatalyst particles 20 and blowing agent particles F to solvent Sb to dissolve the blowing agent particles F, and a step of evaporating the solvent Sb to produce a photocatalyst blowing agent composite 20F that combines the photocatalyst particles 20 and the blowing agent particles F. This allows the photocatalyst blowing agent composite 20F to be easily produced by adding the photocatalyst particles 20 and the blowing agent particles F to solvent Sb to dissolve the blowing agent particles F, and then evaporating the solvent Sb.

[0075] As explained with reference to Figures 5B and 5C, the photocatalyst particle-containing resin composition 100m of this embodiment shown in Figure 5B can be heated to produce a photocatalyst particle-containing resin composition 100 in which the embedding of the photocatalyst particles 20 is suppressed, as shown in Figure 5C.

[0076] The photocatalyst particle-containing resin composition 100m of this embodiment comprises a photocatalyst blowing agent composite 20F obtained by combining photocatalyst particles 20 and blowing agent particles F, and a resin 10r in which the photocatalyst blowing agent composite 20F is dispersed. By heating the photocatalyst particle-containing resin composition 100m in which the photocatalyst blowing agent composite 20F obtained by combining photocatalyst particles 20 and blowing agent particles F is dispersed in the resin 10r, the blowing agent particles F of the photocatalyst blowing agent composite 20F are expanded, whereby the photocatalyst particles 20 can be effectively positioned on the surfaces of the pores 10h formed in the porous resin 10, thereby improving the photocatalytic efficiency.

[0077] When the foaming agent particles F are chemical foaming agents, they are usually solid and therefore easily complexed with the photocatalyst particles 20. However, organic foaming agent particles F such as ADCA are poorly soluble in water and may not complex with the hydrophilic photocatalyst particles 20. For this reason, it is preferable that the foaming agent particles F are water-soluble. For example, it is preferable to use sodium bicarbonate (baking soda) as the foaming agent particles F. It is also more preferable that the foaming agent particles F be an inorganic compound in order to suppress decomposition by the photocatalyst particles 20.

[0078] When the blowing agent particles F are bicarbonate, the bicarbonate generates carbon dioxide through thermal decomposition, which generates bubbles in the resin 10r, allowing foaming. Bicarbonate salts include potassium salts, calcium salts, and ammonium salts, but sodium salts are preferred because they have an easy-to-handle decomposition temperature, are relatively stable when stored, and produce non-toxic decomposition products.

[0079] As described above, the foaming agent particles preferably contain sodium bicarbonate. By including sodium bicarbonate in the foaming agent particles, foaming can be achieved using a material that is relatively easy to obtain. Furthermore, since sodium bicarbonate is easily soluble in water, a composite of the photocatalyst particles 20 and the sodium bicarbonate-containing particles can be easily produced by vaporizing the water in which sodium bicarbonate is dissolved.

[0080] When the photocatalyst particles 20 are tungsten oxide, the pH of the solvent Sb to which the photocatalyst particles 20 are added is preferably 2 to 7 in order to prevent dissolution and aggregation of the photocatalyst particles 20. This is because, when the solvent Sb to which the photocatalyst particles 20 are added is basic, tungsten oxide as the photocatalyst particles 20 is easily dissolved, and the isoelectric point of tungsten oxide is pH 2 or less, so that it is easily aggregated.

[0081] 5B and 5C, for ease of understanding of the invention, the photocatalyst particle-containing resin composition 100 in which the foaming agent particles F are expanded is generated by heating the film-like photocatalyst particle-containing resin composition 100m, but the foaming agent particles F may also be expanded when molding the photocatalyst particle-containing resin composition 100. For example, molding of the photocatalyst particle-containing resin composition 100 and / or foaming of the foaming agent particles F may be performed during injection molding and / or extrusion molding.

[0082] In the above description with reference to Figures 1 to 5C, the foaming agent particles F of the photocatalyst foaming agent composite 20F are foamed in the resin 10r, thereby producing a photocatalyst particle-containing resin composition 100 in which the photocatalyst particles 20 are effectively dispersed in the porous resin 10, but this embodiment is not limited to this.

[0083] Typically, the foaming agent particles F are expanded by heating the foaming agent particles F in the resin 10r. At this time, depending on the heating temperature, the foaming agent particles F may not expand properly. Furthermore, even if heated, the foaming agent particles F may not expand sufficiently. For this reason, foaming assistant particles may be dispersed in the resin 10r together with the foaming agent particles F, and the foaming assistant may cause the foaming agent particles F to expand efficiently.

[0084] Next, a method for producing the photocatalyst particle-containing resin composition 100 of this embodiment will be described with reference to Figures 1 to 6. Figure 6 is a flow diagram for explaining the method for producing the photocatalyst particle-containing resin composition 100 of this embodiment. The flow diagram of Figure 6 is similar to the flow diagram of Figure 3 except that a photocatalyst-foaming assistant composite in which photocatalyst particles 20 and foaming assistant particles are composited is used, and therefore, duplicated explanations will be omitted to avoid redundancy.

[0085] 6, in step S202, a photocatalyst foaming assistant composite obtained by combining photocatalyst particles 20 and foaming assistant particles, and foaming agent particles are dispersed in a resin. For example, a photocatalyst foaming assistant composite obtained by combining photocatalyst particles 20 and foaming assistant particles is produced in advance, and then dispersed in a resin together with the foaming agent particles.

[0086] [Foaming aid particles] The foaming aid particles promote the expansion of the foaming agent particles. When the foaming agent particles are heated in the vicinity of the foaming aid particles, they expand more easily than when no foaming aid particles are present. The foaming aid particles can lower the foaming temperature of the foaming agent. Alternatively, the foaming aid particles can reduce the size of the foam of the foaming agent, thereby reducing the size of the pores formed by the foaming agent particles.

[0087] Examples of materials for the foaming aid particles include urea compounds, metal oxides such as zinc oxide, aliphatic metal salts, and organic salts such as citrates. Examples of materials for the foaming aid particles that can be suitably combined with sodium bicarbonate as the foaming agent particles include citric acid and citrates. In this case, the foaming of the foaming agent particles is also promoted by the neutralization reaction between the foaming agent particles and the foaming aid particles.

[0088] Examples of materials for the foaming aid particles that undergo a neutralization reaction with the hydrogen carbonate as the foaming agent particles include calcium phosphate, d-tartaric acid, potassium d-hydrogen tartrate, gluconolactone, and ammonium chloride. From the viewpoint of the generated gas, it is preferable that the material for the foaming aid particles does not contain ammonium salt.

[0089] [Photocatalytic foaming assistant complex] The photocatalyst-foaming assistant composite is produced by combining the photocatalyst particles 20 and the foaming assistant particles. For example, in the photocatalyst-foaming assistant composite, the photocatalyst particles 20 and the foaming assistant particles are in close contact with each other.

[0090] [Production of photocatalyst-foaming assistant complex] The photocatalyst foaming assistant composite is produced by mixing photocatalyst particles and foaming assistant particles. The photocatalyst foaming assistant composite may be produced by mixing the photocatalyst particles 20 and the foaming assistant particles in a room temperature environment. For example, the photocatalyst foaming assistant composite may be produced by mixing the photocatalyst particles 20 and the foaming assistant particles while heating the photocatalyst particles 20 and the foaming assistant particles.

[0091] Alternatively, the photocatalyst-foaming assistant composite may be produced by mixing the photocatalyst particles 20 and the foaming assistant particles in a solvent. In this case, the photocatalyst-foaming assistant composite may be produced from the photocatalyst particles 20 and the foaming assistant particles by evaporating the solvent. At least one of the photocatalyst particles 20 and the foaming assistant particles may be dissolved in the solvent.

[0092] In step S204, the foaming agent particles are foamed in the resin. For example, by heating the resin, the foaming agent particles react with the foaming assistant particles in the photocatalyst-foaming assistant composite, causing the foaming agent particles to foam in the resin.

[0093] The foaming of the foaming agent particles in the resin produces a porous resin 10 with a plurality of pores 10h formed therein. This produces a photocatalyst particle-containing resin composition 100. The plurality of pores 10h are formed by the foaming agent particles and the foaming agent particles of the photocatalyst foaming assistant composite, and therefore the photocatalyst particles 20 of the photocatalyst foaming assistant composite are located in the plurality of pores 10h.

[0094] According to this embodiment, the photocatalytic efficiency can be improved because the photocatalytic particles 20 can be effectively positioned on the surfaces of the pores 10h formed in the porous resin 10 by the expansion of the foaming agent particles F.

[0095] As described above, this embodiment includes a step of dispersing a photocatalyst foaming assistant composite, which is a composite of photocatalyst particles 20 and foaming assistant particles, and foaming agent particles in a resin, and a step of foaming the foaming agent particles in the resin. The foaming assistant particles of the photocatalyst foaming assistant composite promote the foaming of the foaming agent particles in the resin, thereby effectively positioning the photocatalyst particles 20 on the surfaces of the pores 10h formed in the porous resin 10, thereby improving the photocatalytic efficiency.

[0096] Next, a method for producing the photocatalyst particle-containing resin composition 100 of this embodiment will be described with reference to Figures 1 to 8C. Figures 7A to 8C are schematic diagrams for explaining the method for producing the photocatalyst particle-containing resin composition 100 of this embodiment. The photocatalyst particle-containing resin composition 100 of Figures 7A to 8C is the same as the method for producing the photocatalyst particle-containing resin composition 100 described above with reference to Figures 4A to 5C, except that instead of a photocatalyst blowing agent composite 20F in which the photocatalyst particles 20 and the blowing agent particles F are composited, a photocatalyst blowing assistant composite 20U in which the photocatalyst particles 20 and the blowing assistant particles U are composited promotes the foaming of the blowing agent particles F, and therefore, redundant explanations will be omitted to avoid redundancy.

[0097] As shown in Fig. 7A, photocatalyst particles 20 and foaming assistant particles U are prepared. Typically, the particle size of the photocatalyst particles 20 is smaller than the particle size of the foaming assistant particles U. Here, the photocatalyst particles 20 are contained in a container D1, and the foaming assistant particles U are contained in a container D2.

[0098] For example, the material of the photocatalyst particles 20 includes tungsten oxide and titanium oxide.

[0099] For example, materials for the foaming aid particles U include citric acid and citrates.

[0100] 7B, photocatalyst particles 20 and foaming assistant particles U are added to the solvent Sb. The solvent Sb is contained in a container D3.

[0101] The solvent Sb is, for example, water. However, the solvent Sb may be a solvent other than water. For example, the solvent Sb may be acidic. Alternatively, the solvent Sb may be neutral.

[0102] To the solvent Sb in the container D3, the photocatalyst particles 20 are added from the container D1, and the foaming assistant particles U are added from the container D2.

[0103] For example, the photocatalyst particles 20 are added to the solvent Sb, and then the blowing agent particles F are added to the solvent Sb. Typically, after the photocatalyst particles 20 are added, the photocatalyst particles 20 are dispersed in the solvent Sb using a disperser. For example, an ultrasonic disperser, a colloid mill, a bead mill, or the like may be used as the disperser.

[0104] Thereafter, the foaming aid particles U are added to the solvent Sb. The foaming aid particles U may be added while stirring the solvent Sb with a liquid mixer. The stirring blades of the liquid mixer can mix the photocatalyst particles 20 and the foaming aid particles U more uniformly. If necessary, a dispersant may be added.

[0105] Alternatively, the foaming assistant particles U may be added to the solvent Sb first, and then the photocatalyst particles 20 may be added to the solvent Sb. Alternatively, the foaming assistant particles U may be added to another solvent and then added to the solvent Sb. Similarly, the photocatalyst particles 20 may be added to another solvent and then added to the solvent Sb.

[0106] At least one of the photocatalyst particles 20 and the foaming assistant particles U is preferably dissolved in the solvent Sb. For example, when the foaming assistant particles U contain citric acid, the citric acid is acidic and dissolves in water as the solvent Sb.

[0107] For example, the solvent Sb is water. When the solvent Sb is water and the photocatalyst particles 20 are tungsten oxide or titanium oxide, the photocatalyst particles 20 are dispersed in water. When the solvent Sb is water and the foaming assistant particles U are citric acid, the foaming assistant particles U are dissolved in water.

[0108] 7C, the solvent Sb is evaporated to produce a photocatalyst blowing assistant composite 20U in which the photocatalyst particles 20 and the blowing agent particles F are combined. In the container D3, the particulate photocatalyst blowing assistant composite 20U is produced.

[0109] In the photocatalyst foaming assistant composite 20U, the components of the foaming assistant particles U dissolved in the solvent Sb appear on the surfaces of the photocatalyst particles 20 that were not dissolved in the solvent Sb. In the photocatalyst foaming assistant composite 20U, the surfaces of the photocatalyst particles 20 are covered with the components of the foaming assistant particles U. In this manner, the photocatalyst foaming assistant composite 20U is produced.

[0110] The photocatalyst-blowing assistant composite 20U may be further pulverized into powder using, for example, an FM mixer or a jet mill.

[0111] 8A, the photocatalyst foaming assistant composite 20U, the foaming agent particles F, and the resin 10r are mixed. Here, the photocatalyst foaming assistant composite 20U is added from a container D3, the foaming agent particles F is added from a container D4, and the resin 10p is added from a container D5 to a resin molding apparatus. Typically, the photocatalyst foaming assistant composite 20U is in a particulate form, the foaming agent particles F are in a particulate form, and the resin 10p is in a pellet or particulate form.

[0112] In a resin molding apparatus, the photocatalyst foaming assistant composite 20U, the foaming agent particles F, and the resin 10p are mixed. The mixture of the photocatalyst foaming assistant composite 20U, the foaming agent particles F, and the resin 10p is preferably mechanically stirred. The resin 10p is melted and molded in the resin molding apparatus. Typically, the molding temperature of the resin 10p is set to a temperature lower than the foaming temperature of the foaming agent particles F. The photocatalyst foaming assistant composite 20U and the foaming agent particles F are dispersed within the resin in which the resin 10p is dissolved.

[0113] Here, the resin molding device produces a film-like molded product, but the resin molding device may also produce a master batch.

[0114] 8B, a photocatalyst particle-containing resin composition 100m, which is a mixture of the photocatalyst foaming assistant composite 20U, the foaming agent particles F, and the resin 10r, is formed into a film shape. The photocatalyst particle-containing resin composition 100m includes the resin 10r, the photocatalyst foaming assistant composite 20U in which the photocatalyst particles 20 and the foaming agent particles F are composited, and the foaming agent particles F. Here, the photocatalyst foaming assistant composite 20U and the foaming agent particles F are dispersed in the resin 10r.

[0115] As shown in Fig. 8C, by heating the photocatalyst particle-containing resin composition 100m, a photocatalyst particle-containing resin composition 100 is produced in which the photocatalyst particles 20 are densely dispersed in the pores 10h in the porous resin 10. In detail, as the composition is heated, the foaming agent particles F located near the photocatalyst foaming assistant composite 20U foam, and as a result, the photocatalyst particles 20 are located in the pores 10h in the porous resin 10 in the photocatalyst particle-containing resin composition 100. Note that the photocatalyst particle-containing resin composition 100 may contain some photocatalyst foaming assistant composite 20U that did not promote the foaming of the foaming agent particles F and some foaming agent particles F that did not foam.

[0116] According to this embodiment, by expanding the foaming agent particles F in the resin using the foaming assistant particles U of the photocatalyst foaming assistant composite 20U, the photocatalyst particles 20 can be effectively positioned on the surfaces of the pores 10h formed in the porous resin 10 by the expansion of the foaming agent particles F. This improves the photocatalytic efficiency.

[0117] As described above, this embodiment includes the steps of adding the photocatalyst particles 20 and the foaming assistant particles U to the solvent Sb to dissolve the foaming assistant particles U, and evaporating the solvent Sb to produce a photocatalyst foaming assistant composite 20U that combines the photocatalyst particles 20 and the foaming assistant particles U. After adding the photocatalyst particles 20 and the foaming assistant particles U to the solvent Sb to dissolve the foaming assistant particles U, the photocatalyst foaming assistant composite 20U can be easily produced by evaporating the solvent Sb.

[0118] As explained with reference to Figures 8B and 8C, the photocatalyst particle-containing resin composition 100m of this embodiment shown in Figure 8B can be heated to produce a photocatalyst particle-containing resin composition 100 in which the embedding of the photocatalyst particles 20 is suppressed, as shown in Figure 8C.

[0119] The photocatalyst particle-containing resin composition 100m of this embodiment includes a photocatalyst foaming assistant composite 20U obtained by combining photocatalyst particles 20 and foaming assistant particles U, foaming agent particles F, and a resin 10r in which the photocatalyst foaming assistant composite 20U and the foaming agent particles F are dispersed. By heating the resin 10 in which the photocatalyst foaming assistant composite 20U obtained by combining photocatalyst particles 20 and foaming assistant particles U is dispersed, the foaming assistant particles U of the photocatalyst foaming assistant composite 20U promote the foaming of the foaming agent particles F, thereby effectively positioning the photocatalyst particles 20 on the surfaces of the pores 10h formed in the porous resin 10, thereby improving the photocatalytic efficiency.

[0120] In addition, when the photocatalyst particles 20 are tungsten oxide, if the solvent Sb is basic, the photocatalyst particles 20 may dissolve in the solvent Sb. Therefore, even when the foaming assistant particles U are dissolved in the solvent Sb, the solvent Sb is preferably acidic or neutral. For example, the foaming assistant particles U are preferably citric acid or a citrate salt.

[0121] In this way, since the pH of the solution in which the foaming assistant particles U are dissolved in the solvent Sb is acidic to neutral, such a solution can be used as a buffer solution to composite the photocatalyst particles 20 with at least one of citric acid and citrate salts as the foaming assistant particles U. This makes it possible to reduce the dissolution of the photocatalyst particles 20 in the solvent Sb compared to composites of basic sodium bicarbonate and the photocatalyst particles 20. In this way, when sodium bicarbonate is used as the foaming agent particles F, citric acid and citrate salts are preferably used as the foaming assistant particles U. Furthermore, the products produced by these foamings are preferred because they have low toxicity.

[0122] As described above, the foaming assistant particles U may contain at least one of citric acid and a citrate salt. When the foaming assistant particles U contain citric acid, the foaming of the foaming agent particles F can be promoted using a relatively easily available material. Furthermore, since citric acid is easily soluble in water, a composite of the photocatalyst particles 20 and the citric acid-containing particles can be easily produced by vaporizing the water in which the citric acid is dissolved.

[0123] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments and can be embodied in various forms without departing from the spirit and scope of the present invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. The drawings mainly show each component in a schematic manner to facilitate understanding. The thickness, length, number, spacing, etc. of each illustrated component may differ from the actual components due to the convenience of drawing. Furthermore, the materials, shapes, dimensions, etc. of each component shown in the above embodiments are merely examples and are not particularly limited. Various modifications are possible within a scope that does not substantially deviate from the effects of the present invention.

[0124] For example, in the description above with reference to Figures 3 to 5C, a composite of photocatalyst particles 20 and blowing agent particles F is used as the photocatalyst blowing agent composite 20F, and in the description above with reference to Figures 6 to 8C, a composite of photocatalyst particles 20 and blowing agent particles U is used as the photocatalyst blowing agent composite 20U, but this embodiment is not limited to this. A composite of photocatalyst particles 20, blowing agent particles F, and blowing agent particles U may also be used. [Industrial Applicability]

[0125] According to the present invention, the photocatalyst particle-containing resin composition and the method for producing the photocatalyst particle-containing resin composition are suitably used. [Explanation of symbols]

[0126] 10 Porous resin 20 Photocatalyst particles 100 Resin composition containing photocatalyst particles 100m Resin composition containing photocatalyst particles F. Foaming agent particles 20F Photocatalytic foaming agent complex U Foaming agent particles 20U Photocatalytic foaming agent complex

Claims

1. a step of dispersing a photocatalyst blowing agent composite obtained by combining photocatalyst particles and blowing agent particles in a resin; expanding the blowing agent particles within the resin; A method for producing a photocatalyst particle-containing resin composition, comprising:

2. adding the photocatalyst particles and the foaming agent particles to a solvent to dissolve the foaming agent particles; a step of evaporating the solvent to form the photocatalyst blowing agent composite in which the photocatalyst particles and the blowing agent particles are combined; The method for producing a photocatalyst particle-containing resin composition according to claim 1, further comprising:

3. a step of dispersing a photocatalyst-foaming assistant composite obtained by combining photocatalyst particles and foaming assistant particles and foaming agent particles in a resin; expanding the blowing agent particles within the resin; A method for producing a photocatalyst particle-containing resin composition, comprising:

4. adding the photocatalyst particles and the foaming aid particles to a solvent to dissolve the foaming aid particles; a step of evaporating the solvent to form the photocatalyst-blowing assistant composite in which the photocatalyst particles and the foaming assistant particles are composited together; The method for producing a photocatalyst particle-containing resin composition according to claim 3, further comprising:

5. The method for producing a photocatalyst particle-containing resin composition according to claim 4 , wherein the foaming aid particles contain at least one of citric acid and a citrate salt.

6. The method for producing a photocatalyst particle-containing resin composition according to claim 1 , wherein the foaming agent particles contain sodium bicarbonate.

7. The method for producing a photocatalyst particle-containing resin composition according to claim 1 , wherein the photocatalyst particles contain tungsten oxide.

8. a photocatalyst blowing agent composite obtained by combining photocatalyst particles and blowing agent particles; a resin in which the photocatalyst blowing agent complex is dispersed; A photocatalyst particle-containing resin composition comprising:

9. A photocatalyst / foaming assistant composite in which photocatalyst particles and foaming assistant particles are combined. blowing agent particles; a resin in which the photocatalyst-foaming assistant composite and the foaming agent particles are dispersed; A photocatalyst particle-containing resin composition comprising:

10. a porous resin having a plurality of pores; Photocatalytic particles dispersed in the porous resin; Equipped with The photocatalyst particle-containing resin composition, wherein the density of the photocatalyst particles decreases from the surface of the pores toward the inside of the porous resin.

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