Method and apparatus for producing a photocatalytic material
First Claim
1. A process for producing a functional material having photocatalytic activity, comprising the steps of:
- coating a photocatalyst coating composition comprising a photocatalytic metal oxide and/or a precursor of the photocatalytic metal oxide onto the surface of a substrate; and
rapidly heating the surface of the coated substrate to fix the photocatalytic metal oxide onto the surface of the substrate, characterized in that;
the rapid heating is carried out by a heating means provided with a heating element having a heating value per unit area of not less than 120 MJ/m2hr, and the distance between the heating element and the surface of the substrate is 5 to 300 mm, and the rapid heating is carried out for 2 to 60 seconds.
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Abstract
Disclosed is a method and an apparatus are provided which can efficiently produce a functional material having a satisfactory level of photocatalytic activity. A photocatalyst coating composition comprising a photocatalytic metal oxide and/or a precursor of the photocatalytic metal oxide is coated on the surface of a substrate. The surface of the coated substrate is rapidly heated to fix the photocatalytic metal oxide onto the surface of the substrate. This rapid heating can realize the production of a functional material having a satisfactory level of photocatalytic activity in an efficient manner. The apparatus, which can continuously carry out the rapid heating immediately after the production of the substrate, can produce the functional material having photocatalytic activity in an efficient manner.
117 Citations
42 Claims
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1. A process for producing a functional material having photocatalytic activity, comprising the steps of:
- coating a photocatalyst coating composition comprising a photocatalytic metal oxide and/or a precursor of the photocatalytic metal oxide onto the surface of a substrate; and
rapidly heating the surface of the coated substrate to fix the photocatalytic metal oxide onto the surface of the substrate, characterized in that;
the rapid heating is carried out by a heating means provided with a heating element having a heating value per unit area of not less than 120 MJ/m2hr, and the distance between the heating element and the surface of the substrate is 5 to 300 mm, and the rapid heating is carried out for 2 to 60 seconds. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 41)
a member selected from the group consisting of silicon, aluminum, potassium, lithium, sodium, cesium, calcium, magnesium, titanium, phosphorus, boron, zirconium, rubidium, francium, yttrium, hafnium, lanthanides, and compounds of said elements; and
an alkali silicate represented by formula Me2O nSiO2 wherein Me represents an alkali metal.
- coating a photocatalyst coating composition comprising a photocatalytic metal oxide and/or a precursor of the photocatalytic metal oxide onto the surface of a substrate; and
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16. The process according to claim 1, wherein an identical photocatalyst coating composition is coated a plurality of times on the surface of the substrate to form a stacked or multi-layered coating, or alternatively, a plurality of different photocatalyst coating compositions are provided followed by successive coating of the plurality of photocatalytic coating compositions onto the surface of the substrate to form a stacked or multi-layered coating.
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17. The process according to claim 1, which comprises the steps of:
- providing at least one coating composition comprising a binder and substantially free from the photocatalytic metal oxide and the precursor of the photocatalytic metal oxide and a photocatalyst coating composition comprising the photocatalytic metal oxide and/or the precursor of the photocatalytic metal oxide or a photocatalyst coating composition comprising the photocatalytic metal oxide and/or the precursor of the photocatalytic metal oxide and the binder;
coating them onto the surface of the substrate to form a multi-layered coating; and
then rapidly heating the assembly.
- providing at least one coating composition comprising a binder and substantially free from the photocatalytic metal oxide and the precursor of the photocatalytic metal oxide and a photocatalyst coating composition comprising the photocatalytic metal oxide and/or the precursor of the photocatalytic metal oxide or a photocatalyst coating composition comprising the photocatalytic metal oxide and/or the precursor of the photocatalytic metal oxide and the binder;
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18. The process according to claim 1, wherein the photocatalyst coating composition further comprises a metal and/or a metal oxide selected from silver, copper, zinc, metals of the platinum group, and oxides of said metals.
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19. The process according to claim 18, wherein the metal and the metal oxide are present, in a supported state, on the surface of the photocatalytic metal oxide.
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20. The process according to claim 19, wherein the metal and the metal oxide have been supported on the surface of the photocatalytic metal oxide by photoreduction fixation using ultraviolet light irradiation.
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21. The process according to claim 1, wherein the concentration of the photocatalytic metal oxide and/or the precursor of the photocatalytic metal oxide in the photocatalyst coating composition is 0.001 to 35% by weight on a solid basis.
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22. The process according to claim 1, wherein the photocatalyst coating composition contains a binder in an amount of 0.001 to 100 parts by weight based on one part by weight of the photocatalytic metal oxide and the precursor of the photocatalyst metal oxide.
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23. The process according to claim 22, wherein the photocatalyst coating composition contains the binder in an amount of 0.1 to 5 parts by weight based on one part by weight of the photocatalytic metal oxide and the precursor of the photocatalytic metal oxide.
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24. The process according to claim 1, wherein the substrate is made of a metal, an inorganic material, an organic material, or a composite material thereof.
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25. The process according to claim 1, wherein the functional material having photocatalytic activity is an interior or exterior material.
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26. The process according to claim 1, wherein the functional material having photocatalytic activity is a tile, a sanitary ware, a table ware, a calcium silicate board, a building material, a ceramic substrate, a semiconductor material, an insulator, a glass, or a mirror.
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28. The apparatus according to claim 27, which carries out the method according to claim 1.
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41. A functional material having photocatalytic activity, produced by the method according to claim 1 or the apparatus according to claim 27.
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27. An apparatus for producing a functional material having photocatalytic activity, said apparatus comprising
at least a rapid heating means for rapidly heating the surface of a substrate coated with a photocatalyst coating composition comprising a photocatalytic metal oxide and/or a precursor of the photocatalytic metal oxide to fix the photocatalytic metal oxide onto the surface of the substrate, characterized in that: -
the rapid heating means comprises at least;
a heating element of which the heating value per unit area is not less than 120 MJ/m2hr and which is provided so that the distance between the heating element and the surface of the substrate is 5 to 300 mm with the distance being fixed or variable;
a heat-resistant material which covers the heating element while forming a given heating space;
a holding means for holding the substrate within the heating space for 2 to 60 seconds;
a carry-in port for carrying the substrate into the heating space; and
a carry-out port for carrying out the substrate from the heating space. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 42)
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Specification