JP2009279505A - Photocatalytic base material and building material comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocatalytic base material which comprises a binder other than an Si-based binder as the binder for binding photocatalyst particles with one another and which has sufficient photocatalytic activity, sufficient performance of fixing particles and adhesive performance. <P>SOLUTION: The photocatalytic base material has a photocatalyst layer comprising photocatalyst particles and the binder. The binder comprises zirconia and the binder content is 10-50 mass% of the whole mass of the photocatalyst layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photocatalytic film for decomposing organic substances and an article provided with the film.

A photocatalyst such as TiO ₂ has an effect of decomposing organic substances and nitrogen oxides and antibacterial deodorizing action. The function is attributed to electrons and holes generated when the semiconductor TiO ₂ is irradiated with light, particularly ultraviolet rays. That is, TiO ₂ which is a semiconductor generates electrons and holes when irradiated with light having energy greater than the band gap. The generated electrons and holes decompose water adsorbed on the TiO ₂ surface to generate H radicals and OH radicals. The organic substance can be decomposed by the reaction of the OH radical with the organic substance. Photocatalysts are also known to have a superhydrophilic surface in addition to the above organic substance decomposing action, and dust or mud that adheres to or accumulates on the surface of the photocatalyst can be self-generated only by natural sunlight and rain. Can be washed. For this reason, articles having a photocatalyst layer are widely used as antibacterial and deodorizing materials, as materials effective for environmental purification by decomposing organic substances, and as materials having a self-cleaning function, both indoors and outdoors. Yes.

  Depending on the application, the photocatalyst needs to be coated on the surface of various materials such as various metal materials, glass and ceramic materials, resin materials and resin coating materials, and further fixed so as not to peel off. As a method for fixing the photocatalyst, a method of coating the surface of the substrate with a photocatalyst by a sol-gel method and baking by heat, or mixing a binder such as water glass or colloidal silica with crystalline photocatalyst particles. A method of fixing on a substrate by coating and drying is known. In particular, the method in which the binder is mixed and applied and dried does not require high-temperature treatment, and is therefore effective when a resin material or resin coating material with low heat resistance is used as the base material. As binders currently used, those containing Si are widely known, and Patent Document 1 discloses one having phenyl group-containing silicon as a binder.

  Further, as a binder other than Si, Patent Document 2 discloses a binder containing a mixture of three types of silicon alkoxide-zirconium compound-colloidal silica, and Patent Document 3 discloses a composite compound containing titanium. Further, Patent Document 4 discloses a binder containing at least one of silica, alumina, zirconia, and titania.

  Further, when a photocatalyst is coated on an organic base material containing a resin material, there is a problem that the base material is decomposed by the decomposition action of the photocatalyst. In order to solve this problem, Patent Documents 5 and 6 disclose photocatalyst coating materials that do not affect the photocatalytic function on the base material by providing an intermediate layer (primer layer) between the photocatalyst layer and the base material. .

JP 2006-122844 A JP-A-2005-350643 Japanese Patent No. 3755852 JP 2003-93890 A JP-A-9-313948 JP 2007-105949 A

  However, as described above, the binders currently used are only Si-based binders, and therefore, there are limits to the types of primers and substrates that can be used as the photocatalytic substrate from the viewpoint of compatibility and adhesion. Further, since the Si-based binder is hydrolyzed in an alkaline solvent, the durability against, for example, an alkaline detergent is poor. On the other hand, when the present inventors experimented on things other than Si-based binders, when the amount of the binder contained in the photocatalyst layer deviates from a certain range, either the photocatalytic function, the particle fixing performance, or the adhesive performance However, there was a problem that it was extremely inferior.

  Therefore, the present invention is a photocatalyst substrate having a photocatalyst layer containing a binder other than Si as a binder for stably joining photocatalyst particles, and is sufficient by limiting the content of the binder in the photocatalyst layer. It is an object of the present invention to provide a photocatalyst substrate that has both photocatalytic activity, sufficient particle fixing performance, and adhesion performance.

  As a result of intensive studies to apply Si-based materials and other undisclosed substances as binders, the present inventor has found that those containing zirconia are effective as binders, and that the content of the binder is set to a certain level. It was found that by satisfying this range, sufficient photocatalytic activity, particle fixing performance, and adhesion performance can be achieved, and the present invention has been achieved.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are added in parentheses, but the present invention is not limited to the illustrated embodiment.

  1st this invention is a photocatalyst base material (100) which has a photocatalyst layer (20) containing a photocatalyst particle (30) and a binder (40) on a base material (10), Comprising: A binder contains a zirconia. The photocatalyst substrate is characterized in that the content of the binder in the photocatalyst layer is 10% by mass to 50% by mass of the entire photocatalyst layer. In the photocatalyst layer, when the binder is zirconia, the photocatalyst layer having sufficient particle fixing performance can be obtained, and further, the photocatalytic activity is sufficient when the binder content is 10% by mass to 50% by mass. And a photocatalyst base material having both sufficient particle fixing performance and adhesive performance. In the present invention, zirconia refers to zirconium dioxide.

  In 1st this invention, it is preferable to have a primer layer (15) between a base material (10) and a photocatalyst layer (20). By providing a primer layer between the photocatalyst layer and the base material, the photocatalyst layer and the base material can be sufficiently bonded even if a material such as a resin that cannot be processed at a high temperature is used as the base material. . In addition, by providing a primer layer between the photocatalyst layer and the base material, the primer layer becomes a barrier layer and does not affect the photocatalytic function on the base material, and even an organic base material can be decomposed. Absent.

  In the first aspect of the present invention, the substrate is preferably a film containing a resin or a sheet (11) containing a resin. Moreover, about a photocatalyst base material, it is preferable that a primer layer (15) exists on a film or a sheet | seat. Due to the presence of the primer layer, the photocatalyst layer (20) and the base material can be sufficiently bonded without subjecting to high temperature treatment, and the base material is protected without affecting the photocatalytic function on the base material. can do.

  2nd this invention is a building material which has the photocatalyst base material (100, 200, 300) concerning the said 1st this invention.

  According to the first aspect of the present invention, fine organic matter is decomposed by a photocatalyst, and antibacterial and deodorizing effects, and further, antifouling effect and snow sliding effect due to super hydrophilicity can be obtained. Since the photocatalyst layer 20 contains zirconia at an appropriate content as the binder 40, it can be a photocatalyst base material having sufficient photocatalytic activity, and the photocatalyst particles 30 in the photocatalyst layer 20 can be stably fixed. Furthermore, since the photocatalyst layer 20 can be firmly adhered to the primer layer 15 or the substrate 10, there is no deterioration of the layer such as peeling, and the photocatalytic activity can be stably maintained even after long-term use. it can.

  Moreover, according to the photocatalyst base material 300, since the base material is a film or sheet containing a resin, it can be easily laminated on an inorganic material such as metal, ceramics, and glass, or an organic material such as polycarbonate. It can be used as a photocatalyst substrate used in a wide range of fields from building materials such as windows and walls, road materials, and industrial materials such as housings of electronic devices.

  Furthermore, by including titanium dioxide as a photocatalyst, high photocatalytic activity and super hydrophilicity can be obtained, and photocatalytic substrates 100, 200, and 300 having excellent antibacterial, deodorizing, self-cleaning, antifouling, and snow sliding performances Can do.

  According to the second aspect of the present invention, since any one of the photocatalyst base materials 100, 200, and 300 is provided on the surface, performance deterioration due to peeling or cracking of the photocatalyst layer 20 hardly occurs. Therefore, even when used for a long time, environmental cleanup performance is maintained, it is hygienic, and it can maintain a beautiful surface with antifouling function, and the snow sliding function makes it easier for snow to slip off naturally. Even during snowfall, the building material is not subjected to a heavy burden due to weight.

  Such an operation and gain of the present invention will be made clear from the best mode for carrying out the invention described below.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

<Photocatalyst substrate 100, 200>
FIG. 1A shows the layer configuration of the photocatalytic substrate 100 according to the first embodiment of the present invention, and FIG. 1B shows the layer configuration of the photocatalytic substrate 200 according to the second embodiment of the present invention. The photocatalyst substrate 100 of the present invention has a photocatalyst layer 20 containing photocatalyst particles and a binder on the substrate 10, and the photocatalyst substrate 200 of the present invention has a primer layer 15 and photocatalyst particles on the substrate 10. And a photocatalyst layer 20 containing a binder in this order. The photocatalyst base materials 100 and 200 of the present invention contain zirconia as a binder in the photocatalyst layer 20, and the content of the binder in the photocatalyst layer 20 is 10% by mass to 50% by mass of the entire photocatalyst layer 20.

(Substrate 10)
If the shape of the base material 10 is a shape which can laminate | stack the photocatalyst layer 20 or the primer layer 15, it will not specifically limit, Flat shape, uneven | corrugated shape, curved surface shape, fibrous shape etc. can be mentioned. Moreover, the material of the base material 10 can be appropriately selected according to the purpose, and specifically includes those containing resin, ceramics, glass, metal and the like.

(Primer layer 15)
The primer layer 15 is a layer that is laminated between the base material 10 and the photocatalyst layer 20 and has a function of blocking the action of the photocatalyst layer 20 so as not to affect the photocatalytic action on the base material 10 side. Moreover, it has the function to adhere | attach the base material 10 and the photocatalyst layer 40 stably.

  The primer of the primer layer 15 is not particularly limited as long as it has a function of stably bonding the base material 10 and the photocatalyst layer 20 and does not affect the photocatalytic action on the base material 10 side. It is formed from a composition containing silicon, alkoxysilane, silicon-modified acrylic, acrylic-modified titanate, etc., and among them, those formed from a composition containing at least one of acrylic-modified silicon, alkoxysilane, and silicon-modified acrylic are preferable. . A primer containing such a substance has good barrier properties and adhesiveness.

  In addition, when the substrate 10 of the photocatalyst substrate 300 is particularly a resin, it is preferable to provide the primer layer 15 between the substrate 10 and the photocatalyst layer 20. The binder containing zirconia is often used as an aqueous coating solution to prevent the binder from gelling, and the aqueous coating solution may be difficult to adjust on the surface of the resin base material 10. This is because it may be difficult to apply on the material. Therefore, when the base material 10 is comprised with resin, it is preferable to provide the primer layer 15 which shows hydrophilic property. In order to constitute a primer layer exhibiting hydrophilicity, it is preferable to use, for example, acrylic-modified silicon or silicon-modified acrylic.

  The thickness of the primer layer 15 is preferably 0.1 μm to 1 μm, and more preferably 0.2 μm to 0.8 μm. If it is thinner than 0.1 μm, sufficient adhesion and barrier properties may not be obtained, and even if it is thicker than 1 μm, almost no improvement in adhesion and barrier properties is seen, resulting in wasted material. Furthermore, the flexibility and the bending resistance may be inferior.

(Photocatalyst layer 20)
The photocatalyst layer 20 includes photocatalyst particles 30 and a binder 40 containing zirconia, and is laminated on the base material 10 or the primer layer 15, and the surface of the photocatalyst layer 20 is exposed to the outside air. The binder 40 stabilizes the photocatalyst particles 30 in the photocatalyst layer 20 and bonds the photocatalyst layer 20 and the base material 10 or the photocatalyst layer 20 and the primer layer 15 together.

  The content of the binder 40 containing zirconia in the photocatalyst layer 20 is 10% by mass to 50% by mass with respect to the entire photocatalyst layer 20, preferably 15% by mass to 35% by mass, and more preferably 20% by mass to 30% by mass. When there is too little content of a binder, photocatalyst particles cannot be connected stably and the photocatalyst layer 20 may become fragile. Moreover, when there is too much content of a binder, the photocatalyst particle which exists in the photocatalyst layer 20 surface will decrease, and sufficient photocatalytic activity may not be obtained.

  Since the binder contains zirconia, the photocatalyst layer 20 having sufficient adhesiveness and stably fixing the photocatalyst particles can be obtained, but depending on the type of the base material 10 and the primer layer 15, zirconia and In addition, a plurality of components other than zirconia (such as a silica-containing compound) may be contained. Specific examples of other components include amorphous titanium oxide, titanium peroxide, alkoxysilane, acrylic-modified silicon, and alkyl titanate. The lower limit of the zirconia content in the binder component is 50% by mass or more, preferably 80% by mass or more of the entire binder component, and the upper limit is 95% by mass or less, preferably 90% by mass or less. If it is 50% by mass or more, the durability in the outdoors will not be lowered and the hydrophilicity of the photocatalyst will not be lowered. If it is 90% by mass or less, sunlight will be scattered and glare will occur. do not do.

  The reason why the photocatalyst particles are stably fixed by including zirconia in the photocatalyst layer 20 is that a three-dimensionally connected three-dimensional structure is formed when zirconia is crystallized, and titanium dioxide is present at that time. This is presumably because oxygen deficiency occurs, and the volume shrinkage accompanying crystallization is suppressed, thereby increasing the force for fixing the photocatalyst particles to the photocatalyst layer 20.

  The lower limit of the mass% of zirconia contained in the photocatalyst layer 20 is 5 mass% or more, preferably 10 mass% or more, more preferably 15 mass% or more, and the upper limit is 50 mass% or less, preferably 40 mass%. % Or less, more preferably 30% by mass or less. If the mass% of zirconia contained in the photocatalyst layer 20 is 5 mass% or more, the photocatalyst particles can be stably fixed to the photocatalyst layer. On the other hand, if the mass% of zirconia contained in the photocatalyst layer 20 is 50 mass% or less, the problem of a decrease in photocatalytic activity due to the photocatalyst particles being hidden by zirconia and not protruding on the surface does not occur.

  Examples of the photocatalyst particles in the photocatalyst layer 20 include metal oxides such as titanium dioxide, zinc oxide, tin oxide, lead oxide, ferric oxide, dibismuth trioxide, tungsten trioxide, and strontium titanate. Of these, titanium dioxide is preferable because it is harmless, chemically stable, and inexpensive. As titanium dioxide, any of anatase-type titanium dioxide, rutile-type titanium dioxide, and brookite-type titanium dioxide can be used, but those mainly composed of anatase-type titanium dioxide having high photocatalytic reaction activity are preferred.

  The particle diameter of the photocatalyst particles is not particularly limited, but considering the adhesion between the particles, the layer thickness, etc., the average particle diameter by the dynamic scattering measurement method is in the range of 1 nm to 500 nm, particularly 2 nm to 300 nm. Some are preferred.

  The thickness of the photocatalyst layer 40 is 0.01 μm to 20 μm, preferably 0.02 μm to 10 μm, and more preferably 0.05 μm to 0.5 μm. If it is thinner than 0.01 μm, sufficient photocatalytic activity may not be obtained, and even if it is thicker than 20 μm, there is almost no improvement in photocatalytic activity, and material may be wasted. , It may become easy to fall off due to bending. Moreover, when the photocatalyst layer is 0.5 μm or less, the photocatalyst layer is preferably not whitened when used outdoors.

<Lamination method of primer layer 15 and photocatalyst layer 20>
The primer layer 15 is laminated on the base material 10. The photocatalyst layer 20 is laminated on the base material 10 or the primer layer 15.

  The method for laminating the primer layer 15 is not particularly limited. After creating a coating liquid containing a primer such as water or an organic solvent and a primer, the coating liquid is applied onto the substrate 10 by various application methods such as gravure coating, dip coating, spray coating, etc., and thereafter, it takes a predetermined time. The primer layer 15 having a predetermined thickness is laminated on the substrate 10 by heating and drying.

  The method for laminating the photocatalyst layer 20 is not particularly limited, and may be the same as the method for laminating the primer layer 15. After creating a coating liquid containing a solvent such as water or an organic solvent, photocatalyst particles, and a binder component, The photocatalyst layer 20 having a predetermined thickness is obtained by applying a coating solution on the base material 10 or the primer layer 15 by various coating methods such as gravure coating, dip coating, spray coating, and the like, and then drying by heating over a predetermined time. Is laminated on the substrate 10 or the primer layer 15.

  In addition, the photocatalyst layer 20 and the primer layer 15 are laminated and integrated in this order on the surface of the base film to form a transfer film, and this transfer film is stacked on the substrate 10 and heated and pressurized, and the photocatalyst layer 10 and the primer layer Alternatively, the primer layer 15 and the photocatalyst layer 20 may be laminated on the substrate 10. If the substrate 10 has heat resistance, titania sol or the like can be applied to the substrate surface and dried to form the photocatalyst layer 20 and then fired to fix the photocatalyst layer 20 to the substrate 10. When the photocatalyst is titanium dioxide, the firing temperature and firing time are preferably about 200 ° C. to 600 ° C. and about 1 to 24 hours. By setting it as such conditions, anatase-type titanium dioxide can be laminated on the substrate surface.

  In the laminating method by coating, it is preferable that the photocatalyst coating liquid coexist with a dispersion stabilizer for preventing change in particle diameter due to particle aggregation and sedimentation. When adjusting the photocatalyst coating liquid, the photocatalyst can be mixed in a powder state, but can also be added and mixed in a slurry or sol state with less sedimentation. Further, commercially available titanium dioxide slurry or sol may be used as long as necessary physical properties are satisfied. The composition and concentration of the coating liquid are not particularly limited, and may be appropriately adjusted in consideration of drying conditions and the like.

  The dispersion stabilizer can coexist from the time of adjusting the particles, or may be added when adjusting the photocatalyst coating liquid. As the dispersion stabilizer, various chemicals can be used. However, since titanium dioxide tends to aggregate near neutrality, an acidic or alkaline dispersion stabilizer is preferable. Examples of the acidic dispersion stabilizer include mineral acids such as nitric acid and hydrochloric acid, and organic acids such as carboxylic acid, oxycarboxylic acid and polycarboxylic acid. Examples of the alkaline dispersion stabilizer include one or more compounds selected from carboxylic acids, alkali metal salts of polycarboxylic acids and ammonia, primary to quaternary amines, and alkanolamines having a hydroxyl group added thereto. As mentioned. In particular, the use of an organic acid is preferable because it has good miscibility with an organic solvent described later, is not extremely low in pH, and does not easily corrode equipment used in production. As the organic acid, acetic acid, oxalic acid, glycolic acid, lactic acid, tartaric acid, malic acid, citric acid and the like can be preferably used, and the dispersion can be stabilized with one or more kinds of acids selected from these.

  Examples of the organic solvent include monohydric lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, polyhydric alcohols such as ethylene glycol and propylene glycol, and esters thereof such as cellosolve, ethyl acetate, methyl isobutyl ketone, isobutanol, and methyl ethyl ketone. , Toluene, xylene and the like can be used. In particular, it is preferable to use a monovalent lower alcohol, particularly isopropyl alcohol and / or ethanol, in view of high volatility and environmental considerations.

  The composition of the coating liquid containing the photocatalyst particles is not particularly limited, but it is preferable that the photocatalyst particles contain 5 to 20% by mass, particularly 5 to 10% by mass in terms of solid content concentration. If it is less than 5%, the effect of the photocatalyst after coating is small and the effect of preventing stains is not sufficient, and if it exceeds 20%, the stability of the coating liquid is lowered and the pot life is lowered.

<Photocatalyst base material 300>
FIG. 1C shows a layer configuration of a photocatalytic substrate 300 that is the third embodiment of the present invention. The photocatalyst base 300 of the present invention has a photocatalyst layer containing the photocatalyst particles 30 and the binder 40 on the film or sheet base 11 containing the resin, or has the primer layer 15 and the photocatalyst layer 20 in this order. . The photocatalyst base material 300 of the present invention contains zirconia as the binder 40 in the photocatalyst layer 20, and the content of the binder in the photocatalyst layer 20 is 10% by mass to 50% by mass, preferably 10%. It is from mass% to 50 mass%, and more preferably from 15 mass% to 30 mass%.

(Film containing resin or sheet 11 containing resin)
The substrate of the photocatalyst substrate 300 is not particularly limited as long as it is a film or a sheet and contains a resin. The type of resin used is not particularly limited, but thermoplastic resins such as ABS, polyvinyl chloride, polyacryl, polystyrene, polyethylene, polypropylene, polycarbonate, PBT, PET, nylon, epoxy, melamine, phenol, polyurethane , Thermosetting resins such as polyimide, polyamide, unsaturated polyester, diallyl phthalate, and furan. When a film or sheet is laminated on a material with a unique color, such as metal or wood, the color is utilized, and when it is laminated on a transparent material such as glass, the transparency It is preferable to make the film or sheet transparent so as not to drop the film. Moreover, the thickness of a film or a sheet | seat is not limited, What is necessary is just to adjust suitably according to the intended purpose.

(Primer layer 15, photocatalyst layer 20, and their lamination method)
The primer layer 15 and the photocatalyst layer 20 are the same as those described above. The photocatalytic substrate 300 includes a resin in the substrate. Therefore, the photocatalyst layer 20 and the base material 11 can be firmly bonded, and the photocatalytic effect of the photocatalyst layer 20 can be prevented from acting on the base material 11 and deterioration of the base material 11 can be prevented. It is preferable to provide a primer layer 15 between 10 and the photocatalyst layer 20. Further, since zirconia is contained in the photocatalyst layer 20 in an appropriate content as the binder 40, the photocatalyst particles 30 in the photocatalyst layer 20 can be stably fixed while having sufficient photocatalytic activity. The layer 20 can be firmly adhered to the substrate 10 or the primer layer 15. For this reason, even if the photocatalyst base material 300 is used for a long period of time, deterioration of the base material 300 due to peeling or the like can be prevented, and a film or sheet having photocatalytic activity and hydrophilicity can be stably formed. Moreover, what is necessary is just to select the method mentioned above suitably for the method of laminating | stacking the primer layer 15 and the photocatalyst layer 20 on the base material 11. FIG.

  Since the photocatalyst substrate 300 is in the form of a film or a sheet, it is easy to carry and can be easily laminated on the surface of building materials, road materials, industrial materials, and the like.

<Building material with photocatalytic substrate>
The photocatalyst substrate of the present invention has stable photocatalytic activity and hydrophilicity as described above. In particular, since the photocatalyst substrate 300 is in the form of a film or a sheet, it is easy to carry and can be easily laminated on materials. . In addition, the building material having the photocatalyst substrate of the present invention is less susceptible to performance deterioration due to peeling or cracking of the photocatalyst layer 20, maintains environmental purification performance even in long-term use, is hygienic, and has an antifouling function. A beautiful surface can be maintained, and the snow sliding function makes it easier for the snow to slip off naturally, so that a heavy burden is not applied to the building materials even during snowfall. The building materials used include various materials such as resins, metals, ceramics, and glass, and the shape, thickness, etc. are not particularly limited.

(Attaching / Laminating Photocatalyst Substrate to Building Materials)
The method for attaching the photocatalyst substrate 100 or the photocatalyst substrate 200 of the present invention to a building material is not particularly limited, but a method of fixing by thermocompression bonding to the surface of the building material, a method of fixing by firing, an adhesive, or the like is used. For example. Moreover, since the photocatalyst base material 300 of the present invention is in the form of a film or a sheet, it can be easily carried in the form of a roll or folded. Therefore, the photocatalyst substrate 300 is transported to the place where the building material on which the photocatalyst substrate is laminated is present, and the photocatalyst substrate 300 cut to a target size is directly attached to the building material using an adhesive or the like at the site. Can do. In addition, in a factory that manufactures building materials, a process is provided for laminating a photocatalytic substrate on the surface of the finished building material using a common laminating method such as coating / drying, heating / pressing, or transferring any photocatalytic substrate. Thus, a building material having a photocatalytic substrate may be produced.

Example 1
The zirconia sol “PTI-5600D” manufactured by Nippon Parkerizing Co., Ltd. was mixed by 20% by mass, and the titanium dioxide sol “PTI-5603S” manufactured by Nippon Parkerizing Co., Ltd. was mixed by 80% by mass. The zirconia sol contains 5% by mass of zirconia and water as a solvent, and the titanium dioxide sol contains 5% by mass of titanium dioxide and water as a solvent. 50 g of this mixed sol was taken, and 50 g of methanol was further added to prepare a photocatalyst coating liquid A. Using this coating liquid A, a polycarbonate plate having a photocatalytic substrate was produced by the following method.

A primer coating solution “Tynoc Primer A (manufactured by Taki Chemical Co., Ltd.)” was applied to an acrylic film substrate “Sanduren NR-38 (manufactured by Kanebo Chemical Co., Ltd.)” and dried. The coating method at this time was performed by a gravure coater, and the primer coating thickness was 2 g / m ² WET. The primer layer was formed by adjusting the substrate speed so that the drying temperature was 80 ° C. and the drying time was 60 seconds. The thickness of the primer layer after drying was 0.2 μm. The prepared coating liquid was applied to the surface of the dried primer layer and dried. The coating method at this time was performed by a gravure roll coater, and the coating thickness was 2 g / m ² WET. The substrate speed was adjusted so that the drying temperature was 80 ° C. and the drying time was 60 seconds. The thickness of the photocatalyst layer after drying was 0.2 μm.

  The photocatalyst substrate thus obtained was heated and laminated on a polycarbonate plate (thickness 2 mm) by melt extrusion molding. The roll temperature during lamination was 120 ° C., and the laminate roll pressure was 0.5 MPa. Thus, a polycarbonate material having a photocatalytic substrate was produced.

(Example 2)
A zirconia sol “PTI-5600D” manufactured by Nihon Parkerizing Co., Ltd. was mixed in an amount of 10% by mass, and a titanium dioxide sol “PTI-5603S” manufactured by Nihon Parkerizing Co., Ltd. was mixed in an amount of 90% by mass. Liquid B was prepared. Using the produced coating liquid B, a polycarbonate plate having a photocatalytic substrate was produced in the same manner as in Example 1.

(Example 3)
A zirconia sol “PTI-5600D” manufactured by Nihon Parkerizing Co., Ltd. was mixed to 50% by mass, and a titanium dioxide sol “PTI-5603S” produced by Nihon Parkerizing Co., Ltd. was mixed 50% by mass. Liquid C was prepared. Using the produced coating liquid C, a polycarbonate plate having a photocatalytic substrate was produced in the same manner as in Example 1.

(Comparative Example 1)
A zirconia sol “PTI-5600D” manufactured by Nihon Parkerizing Co., Ltd. was mixed in an amount of 5% by mass, and a titanium dioxide sol “PTI-5603S” manufactured by Nihon Parkerizing Co., Ltd. was mixed in an amount of 95% by mass. Liquid D was prepared. Using the prepared coating liquid D, a polycarbonate plate having a photocatalytic substrate was produced in the same manner as in Example 1.

(Comparative Example 2)
A zirconia sol “PTI-5600D” manufactured by Nihon Parkerizing Co., Ltd. was mixed to 55% by mass, and a titanium dioxide sol “PTI-5603S” manufactured by Nihon Parkerizing Co., Ltd. was 45% by mass. Liquid E was produced. A polycarbonate plate having a photocatalytic substrate was produced in the same manner as in Example 1 using the produced coating liquid E.

(Comparative Example 3)
Amorphous titanium oxide sol “PTI-5600B” manufactured by Nippon Parkerizing Co., Ltd. was mixed to 20% by mass, and titanium dioxide sol “PTI-5603S” manufactured by Japan Parkerizing Co., Ltd. was mixed 80% by mass, and methanol was added as in Example 1. Photocatalyst coating solution F was produced. Using the prepared coating liquid F, a polycarbonate plate having a photocatalytic substrate was produced in the same manner as in Example 1.

(Comparative Example 4)
The mixture was mixed so that 98 parts of amorphous type titanium oxide sol “PTI-5600B” manufactured by Nippon Parkerizing Co., Ltd. and 2 parts of colloidal silica “OX-50” manufactured by Nippon Aerosil Co., Ltd. were added. Liquid G was prepared. At this time, the concentration of titanium oxide in the photocatalyst coating solution G is 4% by mass, and the concentration of silica is 1% by mass. Using the produced coating liquid G, a polycarbonate plate having a photocatalyst substrate was produced in the same manner as in Example 1.

  About said Examples 1-3 and Comparative Examples 1-4, the following evaluations 1-5 were performed.

(Evaluation 1)
Each sample was cut into a 30 cm square and installed outdoors facing south at a 45 degree angle with respect to the ground, and the durability and weather resistance of the sample were evaluated. The place of exposure was Naha City, Okinawa Prefecture, and the installation period was May to December 2006. After the exposure, the test piece was collected and the state of the sample was observed.

(Evaluation 2)
Each sample is cut into a 5 × 10 cm square, and a black light blue lamp “FL-20S BLB (manufactured by Matsushita Electric Works)” is used on the surface of the sample so that ultraviolet light with a wavelength of 365 nm is 1 mW / cm ² · s. After 240 hours of irradiation, the contact angle of the irradiated surface was measured.

(Evaluation 3)
Each sample was cut into a 10 cm square, and the methylene blue decomposition rate was determined by the methylene blue wet method established by the “Photocatalyst Product Forum”.

(Evaluation 4)
Each sample was cut into a 30 cm square and placed southward so as to have an angle of 45 degrees with respect to the ground. The place of exposure was Nagano Prefecture, and the installation period was from December 2006 to March 2007. During the period, the state of snow height on each sample was observed immediately after the snow.

(Evaluation 5)
Each sample was cut into 5 × 10 cm squares and immersed in a 0.1N NaOH aqueous solution for 24 hours. After 24 hours, the sample was taken out and washed with running water, and then the presence or absence of the photocatalyst coat layer was determined by the following method.

1 ml of an aqueous solution of silver nitrate (AgNO ₃ ; manufactured by Wako Pure Chemical Industries, Ltd.) having a concentration of 0.1 mol / l was dropped, and the intensity of 365 nm wavelength was 1 mW / mm using National's “Black Light Blue Lamp FL-20BLB” as a light source. UV light was irradiated for 1 minute so as to be cm ² · sec. Calibration of the UV intensity was performed by connecting the light receiving unit “UD-36” to Topcon “UVR-2”. Water droplets were removed after irradiation with UV light. When the photocatalyst layer remains, silver reduced from silver ions by the photocatalytic reaction is deposited, and the blackening of the photocatalyst surface layer can be visually confirmed. When blackening is not recognized visually, it indicates that the photocatalyst layer has fallen off.

(Result: Evaluation 1)
The results are shown in Table 1. From Evaluation 1, Examples 1 to 3 and Comparative Example 2 were not changed at all or only slightly changed. From this, it can be said that in Examples 1 to 3 and Comparative Example 2, the binder in the photocatalyst layer was contained in an appropriate amount or more, and thus the layer such as peeling was not deteriorated. On the other hand, for Comparative Example 1, because the binder content was too small, the photocatalyst layer was not stably fixed and dropped off, and for Comparative Examples 3 and 4, the binder was other than zirconia, A sufficient adhesion effect could not be obtained, and the sample surface became white and floated.

(Result: Evaluation 2)
From Evaluation 2, in Examples 1 to 3 and Comparative Examples 1, 3, and 4, the contact angle of the ultraviolet irradiation surface was greatly reduced. Thus, Examples 1-3, Comparative Examples 1, 3, and 4 are such that the binder content in the photocatalyst layer does not significantly impair the photocatalytic effect, and the photocatalyst in the photocatalyst layer makes the superhydrophilic property. It turns out that it has. On the other hand, in Comparative Example 2, since the amount of the binder was too large, sufficient hydrophilicity could not be obtained, and the contact angle became large.

(Result: Evaluation 3)
From Evaluation 3, in Examples 1 to 3 and Comparative Examples 1, 3, and 4, the methylene blue decomposition rate was large. From this, it can be seen that Examples 1 to 3 and Comparative Examples 1, 3 and 4 have sufficient photocatalytic activity because the binder content in the photocatalyst layer is such that the photocatalytic effect is not significantly inhibited. On the other hand, since the comparative example 2 had too much binder, sufficient photocatalytic activity was not obtained.

(Result: Evaluation 4)
From Evaluation 4, Examples 1 to 3 and Comparative Examples 1, 3, and 4 had a small amount of snow remaining during snowfall. From this, it can be seen that Examples 1 to 3 and Comparative Examples 1, 3, and 4 maintain hydrophilicity at a level at which snow can be dropped during snowfall. On the other hand, it was found that Comparative Example 2 cannot obtain a sufficient snow sliding effect because of its low hydrophilicity.

(Result: Evaluation 5)
From Evaluation 5, in Examples 1 to 3 and Comparative Examples 1 and 2, the photocatalyst layer did not fall off after alkali immersion. This proved that the zirconia binder has alkali resistance. On the other hand, it turned out that the photocatalyst film | membrane which used the silica of the comparative example 4 as a binder is inferior to durability with respect to alkalinity.

  From the above evaluation results, Examples 1 to 3 are photocatalytic substrates having sufficient photocatalytic activity and superhydrophilicity, and sufficient substrate durability and weather resistance. It was a photocatalyst substrate having defects in any of photocatalytic activity, hydrophilicity, and durability. In addition, Comparative Example 4 was a photocatalytic substrate having defects in durability, weather resistance, and alkali resistance. From this, the superiority of the zirconia binder over the Si-based binder was confirmed.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. However, the invention can be changed as appropriate without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and the photocatalyst substrate, photocatalyst substrate, and material having the photocatalyst substrate accompanied by such changes are also included. It should be understood as being included within the scope of the present invention.

It is a schematic diagram which shows the layer structure of the photocatalyst base material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base material 11 Film or sheet-like base material containing resin 15 Primer layer 20 Photocatalyst layer 30 Photocatalyst particle 40 Binder containing zirconia 100, 200 Photocatalyst base material 300 Film or sheet-like photocatalyst base material

Claims (4)

A photocatalyst substrate having a photocatalyst layer containing photocatalyst particles and a binder on a substrate, wherein the binder contains zirconia, and the content of the binder in the photocatalyst layer is 10% by mass to 50% by mass of the entire photocatalyst layer A photocatalyst base material, characterized in that it is mass%. The photocatalyst base material of Claim 1 which has a primer layer between the said base material and the said photocatalyst layer. The photocatalyst substrate according to claim 1, wherein the substrate is a film containing a resin or a sheet containing a resin. The building material which has a photocatalyst base material in any one of Claims 1-3.

Images