JP2003171604A - Antibacterial photocatalytic coating material and antibacterial photocatalytic member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antibacterial photocatalytic coating material which is made by using a photocatalyst comprising a low-cost oxide capable of exhibiting a photocatalytic activity in a visible light region based on a simple new mechanism, and using an aqueous solvent, and which has antibacterial, mildewproofing and alga-preventive effects as well as hot-water resistance and alkali resistance, and to provide an antibacterial photocatalytic member. <P>SOLUTION: The antibacterial photocatalytic coating material contains a silicone acrylic emulsion coating, an aqueous solvent and a photocatalyst, wherein the photocatalyst comprises an oxide composite having a joint by oxide semiconductors (I) and (II) having characteristics photocatalytic for each other, and different in both the energy level of electrons on the bottom of the conduction band and the energy level of electrons at the top of the valence band in an energy band structure on the basis of a vacuum level, and at least the oxide semiconductor (I) has photocatalytic characteristics even in a visible light region. The antibacterial photocatalytic member is obtained by using the coating material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antibacterial photocatalyst paint and an antibacterial photocatalytic member having antibacterial, antifungal, and antialgal action.

[0002]

2. Description of the Related Art Antibacterial photocatalytic paints include organic paints and inorganic paints. Antibacterial organic coatings containing an antibacterial agent in an organic resin deteriorate the resin when used for a long time, and especially when used outdoors, stains adhere to the surface and deterioration due to ultraviolet rays causes There is a drawback that performance tends to decrease. On the other hand, inorganic coatings containing an antibacterial agent in a silicate-based, phosphate-based, or zirconium-based inorganic composition have better durability than the above-mentioned organic coatings, but all require baking at a high temperature of 200 ° C or higher. Therefore, it is difficult to apply a coating directly to building materials and plastics, and the usable range is limited. Japanese Patent No. 2776259 discloses an inorganic coating composed of a silicon compound and / or colloidal silica, and an antibacterial photocatalytic inorganic coating containing an antibacterial agent.
There is disclosed an inorganic coating which can be baked at 200 ° C. or lower, has flexibility, and can maintain antibacterial performance for a long period of time. However, since a silicon compound is used as a binder, it has a drawback of being inferior in hot water resistance and alkali resistance.Also, in this inorganic paint, it is dispersed in a non-aqueous organic solvent such as alcohol, but recently, due to environmental problems, a solvent is used. There is an increasing demand for antibacterial photocatalyst paints that are not used.

As a material exhibiting antibacterial properties, a coating material containing titanium oxide in the coating film and having a self-cleaning function has recently been attracting attention. When a coating film is formed using this paint, the anatase-type titanium oxide in the coating film absorbs the ultraviolet rays contained in the sun rays to generate electrons and holes.
Since the generated holes have strong oxidizing power, they decompose organic substances and the like adhering to the surface of the coating film, thereby preventing contamination of the coating film surface with organic substances.

However, titanium oxide exhibits its performance as a photocatalyst only for ultraviolet rays. Since ultraviolet rays make up only about 4% of the sun's rays outdoors, it is generated by absorbing a visible light by adsorbing a pigment on titanium oxide with the aim of making titanium oxide highly functional and responsive in the visible light range. The method of injecting electrons into the titanium oxide from the excited state of the adsorbed dye, the method of chemically injecting metal ions such as Cr, V, Mn, Fe, and Ni, the method of introducing oxygen defects by plasma irradiation, and the different ions Various attempts have been made domestically and internationally, such as the method of introduction. However, none of these methods has been industrialized because of problems such as difficulty in uniform dispersion, reduction of photocatalytic activity due to recombination of electrons and holes, and high adjustment cost.

In addition, perovskite type oxides have recently attracted attention as having catalytic activity. For example,
In Japanese Patent Application Laid-Open No. 7-24329, the general formula A ³⁺ B
³⁺ etc. O ₃ at a LaFeO ₃ and in formula A ²⁺ B ³⁺ Ox SrMnOx have been proposed, but not the high catalytic activity is obtained. Further, researches on layered perovskite type oxides have been actively conducted. For example, JP-A-1
0-244164 discloses a layered perovskite type A
BCO ₄ is described, Japanese Patent Application Laid-Open No. 8-196912 describes KLaCa ₂ Nb ₃ O ₁₀ type composite oxide, and Japanese Patent Application Laid-Open No. 11-139826 describes KC.
a ₂ Nb ₃ O ₁₀ has been proposed. These principles and manufacturing methods are complicated, and the chemical stability of the obtained oxide is also problematic, so that they have not been industrialized.

[0006]

SUMMARY OF THE INVENTION The present invention uses an inexpensive composite oxide photocatalyst that exhibits photocatalytic activity based on a simple new mechanism in the visible light region, and uses a water-based solvent to provide warm water resistance and alkali resistance. Another object of the present invention is to provide an antibacterial photocatalytic coating and an antibacterial photocatalytic member having antibacterial, antifungal and algae-proofing properties.

[0007]

The first invention of the present invention is as follows:
An antibacterial photocatalyst paint containing a silicone acrylic emulsion paint, an aqueous solvent and a photocatalyst, wherein the photocatalysts have photocatalytic properties with each other, and the energy level of electrons at the bottom of the conduction band in the energy band structure based on the vacuum level The photocatalyst is composed of an oxide composite having a junction of oxide semiconductors (I) and (II) in which the energy levels of electrons at the top of the valence band are different, and at least the oxide semiconductor (I) is in the visible light range. Provided is an antibacterial photocatalyst coating having characteristics.

A second invention is the antibacterial photocatalyst paint according to the first invention, wherein the silicone acrylic emulsion paint containing the photocatalyst is a composite of polyorganosiloxane and acrylic polymer. provide.

A third invention provides the antibacterial photocatalyst paint according to the first or second invention, wherein the paint containing the photocatalyst is a room temperature crosslinking type.

A fourth invention is that the photocatalyst is an oxide semiconductor.
The body (I) has the composition formula (III) A_2-XB_{2 + X}O_8-2δ (however,
-0.4 <X <+0.6 and -0.5 <2δ <+
A) ion represented by 0.5) and having multiple valences
And composition formula (IV) A in which B ions are regularly arranged
_2-X ³⁺B_{2 + X} ⁴⁺O_{7+ (X / 2) + Y}(However, -0.4 <X <+
Pyrochrome with 0.6 and -0.2 <Y <+0.2)
Oxygen deficiency position or penetration from the fluorite structure of a-type oxide
At least one of the mold insertion positions has oxygen ions inserted.
It is composed of oxide related structure
Body (II) is rutile type or anatase type or this
Titanium oxide, zinc oxide, tin oxide, which is a mixture of two types such as
Either zirconium oxide or strontium titanate
The antibacterial optical touch according to the first invention, characterized in that
Providing medium paint.

A fifth aspect of the present invention provides the antibacterial photocatalyst coating material according to any one of the first to fourth aspects, wherein the photocatalyst carries an antibacterial metal.

A sixth invention is an antibacterial photocatalytic member characterized in that the antibacterial photocatalyst coating composition according to the first to fifth inventions is applied to a substrate and cured to form an antibacterial photocatalytic film. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. First,
The photocatalyst according to the present invention is an oxide semiconductor having photocatalytic properties and having different energy levels of electrons at the bottom of the conduction band and electrons at the top of the valence band in the energy band structure based on the vacuum level. At least an oxide semiconductor (I), which is composed of an oxide composite having a junction formed by (I) and (II)
Is characterized by having photocatalytic properties even in the visible light range.

As the above oxide semiconductor (I) having photocatalytic properties even in the visible light region, which constitutes one of the oxide composites, for example, the composition formula (III) A _2-X B _{2 + X} O _{8- 2} δ (However, -0.4 <X <+0.6, and -0.5 <2δ <
+0.5), and the composition formula (IV) A _2-X ³⁺ B _{2 + X} ⁴⁺ O _{7+ X / 2) + Y} (However, -0.4 <
X <+0.6 and -0.2 <Y <+0.2) Pyrochlore in which oxygen ions are inserted at at least one of the oxygen deficiency position and the interstitial position as seen from the fluorite structure of the pyrochlore type oxide. Related structure oxides and composition formula (VI) A ²⁺
It is represented by B ⁴⁺ O _{3 −} δ (−0.1 <δ <0.1) and the A ion is 1 selected from alkaline earth metal elements.
More than one element, B ion is lanthanoid, IVa group element,
Examples thereof include perovskite-type oxides, which are one or more elements selected from Group IVb elements. In this perovskite type oxide, the δ value was −0.1 <δ <0.1.
The reason for this is that it is not possible to obtain one outside the above numerical range due to manufacturing conditions.

In the above-mentioned pyrochlore-related structure oxide, the inserted oxygen ion is easy to move and is active, and oxygen can be inserted also in the oxygen deficient position or intrusive position as seen from the fluorite structure, so that the oxygen ion is dissolved. The present inventors have already found that it is a material that has a large number of sites and has a very high catalytic activity, and that it also has a photocatalytic effect effectively against visible light. Furthermore,
By substituting the A ion with a cation having a lower valence or an expensive number, or by substituting the B ion with a cation having a lower valence or an expensive number to change the amount of inserted oxygen ions, the energy band gap and defects can be improved. It is also possible to control the light absorption characteristics by changing the level.

Examples of the oxide semiconductor (II) constituting the other of the oxide composites include rutile type or anatase type or titanium oxide, zinc oxide, tin oxide in which these two types are mixed, Examples thereof include zirconium oxide and strontium titanate.

As the oxide semiconductor (I), the composition formula (III) A _2-X B _{2 + X} O _8-2 δ (where -0.4 <X <
+0.6 and -0.5 <2δ <+0.5) using a pyrochlore related structure oxide (Ce ₂ Zr ₂ O ₈ ) powder, and anatase type as the oxide semiconductor (II) The following has been confirmed from Example 1 and the like described below using titanium oxide powder.

That is, the Ce ₂ Zr ₂ O ₈ powder and the anatase-type titanium oxide powder were mixed in a weight ratio of Z: (1-Z) [where 0 <Z <1] and 700 ° C.
After baking for 1 hour, the powder (photocatalyst) according to Example 1 was prepared by crushing in a mortar.

Here, the oxide semiconductors (I) and (II) having different energy levels at the bottom of the conduction band and at the top of the valence band in the energy band structure based on the vacuum level are bonded to each other. Then, it is generally known that electrons and holes respectively flow in one direction near the junction. At this time, due to the adsorption phenomenon promoted by the light irradiation, electrons and holes flowing in the junction portion tend to be separated from each other. In the case of the above oxide composite composed of a pyrochlore-related structure oxide and titanium oxide, holes flow on the surface of the junction (on the side in contact with the outside), and electrons flow on the center of the junction. Separating the flow of electrons and holes at the junction leads to spatial separation of electrons and holes in the entire oxide complex, and recombination of electrons and holes excited by light is suppressed. It As a result, the reaction positions of the photocatalytic reaction involving the electrons and holes are spatially separated, so that it is presumed that the photocatalyst will have a significantly increased catalytic activity due to the above-mentioned joining.

Furthermore, by varying the combination of the above oxide semiconductors (I) and (II), it is possible to control the electron energy and hole energy involved in the photocatalytic reaction occurring near the heterojunction or homojunction. As described above, various advantages can be obtained by using an oxide composite having a junction of different or the same kind of oxide semiconductor.

The junction of the oxide complex composed of the pyrochlore-related structure oxide and titanium oxide is a heterojunction because it is a junction between different oxide semiconductors. Also,
Another example of the oxide complex having a heterojunction is a composition formula A ²⁺ B ^{4 +} _1-x C ³ in which a cation C having a lower valence than B ions is doped in a range of up to 50 mol%. ⁺ _x O _3- δ (however,
0 <X ≦ 0.5 and 0 <δ <0.5), A ions are one or more elements selected from alkaline earth metal elements, B ions are lanthanoids, and IVa group elements , One or more elements selected from IVb group elements, C ions are doped with an acceptor having a photocatalytic property in the visible light region, which is composed of one or more elements selected from lanthanoids, IIIa group elements, and IIIb group elements P-type oxide semiconductor perovskite-type oxide and nitrogen-doped p-type oxide semiconductor
Type oxide semiconductor composed of titanium oxide and an oxide composite, or the above composition formula (VI) A ²⁺ B ⁴⁺ O _{3 −} δ
It is represented by (-0.1 <δ <0.1), the A ion is one or more elements selected from alkaline earth metal elements, and the B ion is selected from lanthanoids, IVa group elements, and IVb group elements. And an oxide complex composed of a perovskite type oxide which is not doped with an acceptor and which has photocatalytic properties even in the visible light range and which is composed of one or more of the above-mentioned elements, and titanium oxide or titanium oxide doped with nitrogen. To be

Further, as a homojunction which is a junction between similar oxide semiconductors, for example, an oxide obtained by mixing and pulverizing titanium nitride (TiN) and titanium oxide (TiO ₂ ), firing treatment, and then pulverizing again. A complex is mentioned. It is presumed that titanium nitride was oxidized by the reaction during the preparation to form titanium oxide doped with nitrogen, so this oxide composite is not doped with nitrogen and titanium oxide doped with nitrogen. It is composed of titanium oxide (that is, the same kind of semiconductor).

Here, the composition formula (III) A exemplified as the oxide semiconductor (I) having photocatalytic properties even in the visible light region
Composition formula (IV) A _2-X ³⁺ B _{2 + X} ⁴⁺ O, which is a precursor of a pyrochlore-related structural oxide represented by _2-X B _{2 + X} O _8-2 δ
Pyrochlore type oxide of _{7+ (X / 2) + Y} and the above composition formula A ²⁺
B ^{4 +} _1-x C ³⁺ _x O _{3 −} δ (where 0 <X ≦ 0.5 and 0
<Δ <0.5) acceptor-doped perovskite-type oxide or composition formula (VI) A ²⁺ B ⁴⁺
The perovskite type oxide represented by O _{3 −} δ (−0.1 <δ <0.1) in which the acceptor is not doped is a conventional solid phase method, that is, an oxide or carbonate of each metal component as a raw material. Although it is synthesized by mixing a salt such as or a nitrate at a target composition ratio and firing, it may be synthesized by a wet method or a vapor phase method other than this.

At present, for example, available ZrO ₂ unavoidably contains about 0.9 to 2.0 mol% of HfO ₂ , and ZrO ₂ is weighed in the state of containing HfO _2. However, the properties of the finally prepared photocatalyst are not deteriorated.

By the way, the above composition formula (III) A_2-XB_{2 + X}
O_8-2Obtain pyrochlore related structure oxide represented by δ
If, in fact, distorted fluorite structure acid as an intermediate oxide
Composition formula (V) t'-A_{0.5- (X / 4)}B_{0.5+ (X / 4)}
O₂Once the phase is produced, the composition formula (V) t'-A
_{0.5- (X / 4)}B_{0.5+ (X / 4)}O₂Composition formula (IV) A by reducing the phase
_2-X ³⁺B_{2 + X} ⁴⁺O_{7+ (X / 2) + Y}Made of Pyrochlore type oxide
And then oxidize the pyrochlore oxide to produce oxygen.
By inserting, composition formula (III) A_2-XB_{2 + X}O_8-2δ
(However, -0.4 <X <+0.6 and -0.5 <2
Pyrochlore related structure oxide represented by δ <+0.5)
Is obtained. In the above composition formula (V), which is an intermediate oxide,
Even if a heterogeneous phase is mixed in the indicated t'phase, subsequent reduction
Pyrochlore type oxide A obtained in_2-X ³⁺B_{2 + X} ⁴⁺O
_{7+ (X / 2) + Y}There is no problem if there are few out-of-orders. Also, the group
Formula (V) t'-A_{0.5- (X / 4)}B_{0.5+ (X / 4)}O₂Intermediate oxidation of
Omit the process of making things, mix the starting raw material powder, and reduce
By reacting in an atmosphere, composition formula (IV) A
_2-X ³⁺B_{2 + X} ⁴⁺O_{7+ (X / 2) + Y}Made of Pyrochlore type oxide
The same composition formula (III)
A_2-XB_{2 + X}O_8-2δ (however, -0.4 <X <+0.6,
And -0.5 <2δ <+0.5)
A lower related structure oxide can be obtained.

Firstly, in order to obtain the above composition formula as intermediate oxide _{(V) t'-A 0.5- (} X / 4) B 0.5+ (X / 4) oxide represented by O _2, the starting material Are weighed, mixed by the ball mill or the like, and pressed into a disk shape of about 15 to 20 mmφ,
3 at 1500-1750 ° C in oxygen-containing gas such as air
Obtained by firing for 0 to 70 hours. Then, grinding the oxide represented by manufactured formula _{(V) t'-A 0.5- (} X / 4) B 0.5+ (X / 4) O 2 to an average particle size 1 to 2 mm. This is placed on a rhodium / platinum foil and heat-treated in an oxygen stream at 500 to 700 ° C. for about 5 hours to adjust the amount of oxygen.

Next, this t'phase is mixed with a 10% H ₂ / Ar or 5% H ₂ / Ar gas stream at 700 to 1350 ° C. for 10 to 10 hours.
Reduce for 20 hours. The mass of the sample taken out after the reduction treatment was precisely weighed, and the composition formula (V) t'-A _{0.5- (X / 4)} B before the reduction treatment was measured.
_{0.5+ (X / 4)} from the mass change from O ₂ phase, resulting formula ^{_{(IV) A 2-X 3+}} B 2 + X 4+ O 7+ (X / 2) + Y pyrochlore type oxide Determine the oxygen content of a product. The composition formula (IV) A _2-X ³⁺ B
_Y in _{2 + X} ⁴⁺ O _{7+ (X / 2) + Y} is an amount showing a portion that changes depending on the valences of A ions and B ions and the amount of the ions in the pyrochlore type oxide. If the A ion is smaller than trivalent and the B ion is smaller than tetravalent,
Y is a negative number. Also, depending on the manufacturing conditions, some of the A ions may wrap around to the B ion position, and some of the B ions wrap around to the A ion position, but this also changes the value of Y. At this time, the value of Y is -0.2
If it is smaller than +0.2, the pyrochlore structure cannot be maintained. Therefore, it is necessary that -0.2 <Y <+0.2 in the composition formula (IV).

After that, the above-mentioned pyrochlore type oxide is placed on a rhodium / platinum foil, and it is heated at 300 to 900 ° C. in an oxygen stream for 5 hours.
If heat-treated for about an hour, oxygen ions can be inserted while maintaining the regular arrangement of cations, and the composition formula (III) A
A pyrochlore-related structural oxide represented by _2-X B _{2 + X} O _8-2 δ (where -0.4 <X <+0.6 and -0.5 <2δ <+0.5) is obtained. To be The heat treatment is 300
If the temperature is lower than ℃, oxygen is not sufficiently inserted into the crystal. Further, when the temperature exceeds 900 ° C., the regular arrangement of the cations collapses to become a random arrangement, and when −0.4> X or +0.6 <X, the amount of precipitation of the different phase increases and the catalytic performance deteriorates.

The obtained pyrochlore-related structural oxide was pulverized in a mortar or the like to form a powder, and the weight ratio to the anatase-type titanium oxide powder obtained by the usual method shown in the following comparative example was Z: (1-Z ) [However, it is measured so that the ratio becomes 0 <Z <1], and mixed using a mortar or a ball mill.

The mixed sample is fired at 300 to 1200 ° C. for about 5 minutes to 1 hour to prepare an oxide composite having a junction of different oxide semiconductors. If the firing temperature is lower than 300 ° C, good bonding may not be obtained, and
If the temperature is higher than 1200 ° C., different reaction phases are generated, and the photocatalytic properties of the oxide composite may deteriorate.

Next, the shape of the photocatalyst according to the present invention is preferably composed of particles having a large specific surface area in order to effectively utilize light, and in general, the size of each particle is 0.1 to 10.
μm, more preferably 0.1 to 1 μm is suitable. As a conventional means for obtaining an oxide composite powder having such a particle size, the pulverization is performed by hand pulverization using a mortar, or by pulverizing each oxide semiconductor using a ball mill or a planetary rotary ball mill. After weighing, mixing and firing the two kinds of powders to obtain an oxide composite having the above-mentioned bonding,
It is pulverized again to obtain a final sample powder.

The obtained photocatalyst having a catalytic activity in the visible light region and the combination of polyorganosiloxane and an acrylic polymer combine the functions of both polymers of film strength (film forming property), weather resistance and water repellency. A silicone acrylic emulsion paint is dispersed in an aqueous solvent (preferably containing water as the main component) to form a paint, and if this is applied and cured at room temperature, the adhesiveness is good and the antibacterial properties are excellent in stain prevention and antibacterial properties. A photocatalytic coating composition and an antibacterial photocatalytic member can be obtained.

Silicone acrylic emulsion paints include general emulsion-polymerized emulsions having a milky white appearance with a particle size of 80 to 500 nm, and colloidal dispersions having a semitransparent blue-white appearance with a particle size of 8 to 80 nm.

In the case of a two-component water-based coating composition to which a curing agent is added, it is preferable to add the curing agent immediately before use. The curing temperature of the composition is 0 ° C to 150 ° C, preferably 1 ° C.
0 ° C to 80 ° C is preferable.

It is also possible to add an antibacterial metal to the photocatalytic substance. Here, as the antibacterial metal, copper,
It is at least one selected from silver, iron, zinc, platinum, gold, palladium, cadmium, cobalt, rhodium, and ruthenium. It is considered that by supporting an antibacterial metal on the photocatalytic substance, charge separation is promoted, the activity of the photocatalyst is improved, and the antibacterial property and antifungal property are improved.

Further, copper acetate or the like may be added to the copper-supported photocatalyst sol, and if necessary, ultraviolet irradiation may be performed to perform photoreduction plating. At this time, if the amount of the metal supported on the photocatalyst solid content is 5 wt% or more, the surface of the photocatalyst particles is covered with the metal and the oxidation points are lost, so that the redox performance of the photocatalyst is deteriorated. Therefore, when copper is carried by photoreduction plating, it is optimal to improve the antibacterial property and the antifungal property by setting the amount of the metal carried in the range of 1 wt% to 5 wt% with respect to the photocatalyst. However, there is no particular limitation when copper or copper oxide is mixed and added.

The photocatalyst and the silicone acrylic emulsion paint are dispersed in an aqueous solvent (preferably containing water as a main component) to prepare a paint, and the surface of an inorganic material such as glass,
Metal surface such as stainless steel, PET, ABS, FRP
(Glass fiber reinforced plastic) Hot water resistance and alkali resistance by applying or spraying to the surface of a base material such as a molded article so as to have a thickness of 0.1 to 200 μm and then curing at room temperature at 10 ° C. to 80 ° C. , A photocatalytic film having good antibacterial and antifungal properties with good adhesion and weather resistance is formed.

In order to exert sufficient antibacterial and antifungal properties by the photocatalyst, it is necessary to add the photocatalyst in an amount of 5 wt% or more based on the solid content. The content of photocatalyst is 8 with respect to the solid content.
When it is added in an amount of 0 wt% or more, the adhesion of the coating, the hot water resistance, the alkali resistance and the weather resistance are lowered because the proportion of the water-based paint is small. Therefore, the amount of photocatalyst added to the silicone acrylic emulsion paint is from 5 wt% to 80 w
t% is desirable.

The antibacterial photocatalyst paint may be applied by various coating methods such as brush coating, spraying, dipping, flow coating and bar coating.

The base material to which the present invention is applicable is a bath,
Bathroom wall material, bathroom floor material, bathroom grating, bathroom ceiling, shower hook, bathtub handgrip, bathtub apron, bathtub drain plug, bathroom window, bathroom window frame, bathroom window floorboard, bathroom lighting fixture. , Drain pan, drain pit, bathroom door,
Bathroom door frame, bathroom window bar, bathroom door bar, slats, mats,
Soap holders, tubs, bathroom mirrors, bath chairs, transfer boards, water heaters, bathroom storage shelves, bathroom handrails, bath lids, bathroom towel racks, shower chairs, bathroom parts such as washbasin holders, etc., Kitchen back for kitchen, kitchen flooring, sink, kitchen counter, drain basket, dish dryer, dish washer, stove, range hood, ventilation fan, stove ignition part, kitchen parts such as knob of stove, urinal, large Toilet bowl, toilet trap, toilet pipe, toilet flooring, toilet wall, toilet ceiling, ball tap, water stopcock, paper wrapper, toilet seat, lifting toilet seat, toilet door, toilet booth key, toilet towel Rests, toilet lids, handrails for toilets, counters for toilets, flush valves, tanks, toilet parts such as spouting nozzles for toilet seats with a cleaning function, wash bowls, wash traps, washrooms Mirrors, wash shelves, drain plugs, toothbrush stands, light fixtures for wash mirrors, wash basins, water soap dispensers, wash basins, mouth washer, hand dryers, wash basins such as rotating towels, washing tubs, washing Machine lids, washing machine pans, dehydration tanks, air conditioner filters, touch panels, faucet fittings, human body detection sensor covers, shower hoses, shower spouts, sealants, joints, etc.

[0041]

EXAMPLES Example 1 Sample Preparation _{(t'-A 0.5- (X /} 4) B 0.5+ (X / 4) production of O ₂ phase) material CeO ₂ powder (Santoku Metal Industry Co., Ltd., purity 99.99%, ig.-loss 3.75%): 1.2353
g, ZrO ₂ powder (manufactured by Santoku Metal Industry Co., Ltd., ZrO ₂ + Hf
Purity of O ₂ 99.60%, ig.-loss 0.45%):
0.8551 g Incidentally, the above "ig.-loss" indicates a loss due to water, an absorbent, or the like.

(Mixing treatment) 1: Each sample after weighing was mixed in a dry manner for 15 minutes using an agate mortar.

2: The sample mixed with the zirconia balls was placed in a glass bottle and ground and mixed for 20 hours using a ball mill.

(Molding treatment) 17 at a pressure of 100 MPa
It was formed into a disk shape of mmφ.

(Sintering Treatment) A sample was placed in a rhodium / platinum crucible and fired in air at 1650 ° C. for 50 hours to produce a t′-Ce _0.5 Zr _0.5 O ₂ phase.

(Pyrochlore type A _2-X ³⁺ B _{2 + X} ⁴⁺ O
_{7+ (X / 2) +} production of _Y) (pulverized) and the sintered body of the t'-Ce _0.5 Zr _0.5 O ₂ phases with an agate mortar and ground to an average particle size of 1 to 2 mm.

(Oxygen content adjustment) This was placed on a rhodium / platinum foil and heat-treated at 600 ° C. for 5 hours in an oxygen stream to adjust the oxygen content. Incidentally, the oxygen-amount adjustment process of t'-Ce _0.5 Zr _0.5 O ₂ phases, most of the trivalent Ce which was included in part in the t'-Ce _0.5 Zr _0.5 O ₂ phase is adjusted to tetravalent.

(Reduction treatment) Next, this t'-Ce _0.5
The Zr _0.5 O ₂ phase was subjected to reduction treatment in a 5% H ₂ / Ar stream at 1300 ° C. for 10 hours. By this reduction treatment, most of Ce in the above t′-Ce _0.5 Zr _0.5 O ₂ phase adjusted to be tetravalent is adjusted to be trivalent and becomes a pyrochlore phase.

(Determination of Oxygen Content of Pyrochlore Phase) The mass of the sample taken out after the reduction treatment was precisely weighed to obtain t ′ before the reduction treatment.
The amount of oxygen in the pyrochlore type oxide was determined from the mass change from -Ce _0.5 Zr _0.5 O ₂ to give Ce ₂ Zr ₂ O _7.02.
Became.

(Production of A _2-X B _{2 + X} O _8-2 δ Phase) (Oxidation Treatment) The above-described pyrochlore type phase (pyrochlore type oxide) after reduction treatment is placed on a rhodium / platinum foil and an oxygen stream is applied. Heat treatment at 600 ℃ for 5 hours to adjust the amount of oxygen to Ce ₂ Z
Pyrochlore related oxide of r ₂ O _8.0 (oxide semiconductor
I) was obtained.

(Production of Anatase Titanium Oxide) Using a titanium sulfate solution, ammonia was used as an alkaline treatment solution to form a hydroxide precipitate, and the precipitate was formed in the atmosphere at 650 ° C. for 1 hour. By baking treatment, anatase type titanium oxide (oxide semiconductor II) was obtained.

(Production of Oxide Complex) (Mixing Treatment) Anatase-type titanium oxide (oxide semiconductor II) and a pyrochlore-related structure oxide of Ce ₂ Zr ₂ O _8.0 (oxide semiconductor I) prepared by the above method. ) Was sampled at the following weight ratio, and was mixed for 30 minutes by a dry method using a zirconia mortar. Titanium _{oxide: 0.4000g, Ce 2 Zr 2 O} 8.0: 0.
1000 g (weight ratio 80:20) (Baking treatment) Each of the mixed samples was placed in a rhodium / platinum crucible and baked in the atmosphere at 700 ° C for 1 hour.

(Pulverization Treatment) The obtained fired product was pulverized for 30 minutes by a dry method using a zirconia mortar to obtain a sample powder.

[Example 2] Sample preparation [Preparation of CaZrO ₃ -δ] (Raw material) CaCO ₃ powder (manufactured by Kojundo Scientific Laboratory Co., Ltd., purity 99.99%, ig.-loss 0.04%): 4 .3
115 g, ZrO ₂ powder (manufactured by Santoku Metal Industry Co., Ltd., ZrO ₂ + Hf
Purity of O ₂ 99.60%, ig.-loss 0.51%):
5.3714 g (Mixing treatment) 1: Using a zirconia mortar, each powder sample after weighing was added with ethanol and mixed for 1.5 hours.

2: The mixed sample was dried, put in a zirconia pot, and ground for 40 minutes using a planetary rotary ball mill.

(Drying treatment) The sample after crushing was placed in a constant temperature bath for 1 hour.
It was dried at 20 ° C. for 30 minutes or more.

(Calcination Treatment) The dried sample was placed in a rhodium / platinum crucible and calcined at 1350 ° C. for 10 hours in the atmosphere.

(Re-grinding / mixing / drying treatment) After calcination, the powder was re-ground in a mortar and mixed in a planetary rotary mill. Then, it dried on the same conditions as the previous drying.

(Molding treatment) 17 at a pressure of 265 MPa
It was formed into a disk shape of mmφ.

(Baking treatment) The sample after molding was treated with rhodium /
It was placed in a platinum crucible and baked in the air at 1650 ° C. for 50 hours.

(Pulverization Treatment) After firing, the powder was pulverized in a zirconia mortar for 1 hour to obtain a sample powder. The composition of the fired product is Ca
It was ZrO _{3 −} δ (the value of δ is a numerical value within −0.1 <δ <0.1. The same applies hereinafter).

(Production of Oxide Complex) Anatase-type TiO ₂ (oxide semiconductor II) and CaZrO _3- δ (oxide semiconductor I) prepared by the same method as in Example 1 were used in the following weight ratios. After collecting and mixing for 30 minutes by a dry method using a zirconia mortar, a sample powder was obtained in the same manner as in Example 1 below. Titanium oxide: 0.6300 g, CaZrO _3- δ: 0.0
701 g (weight ratio 90:10) (Second step) Method for producing photocatalyst paint and photocatalyst-containing coating film Room temperature curing type water-based silicone acrylic emulsion paint (Kaneka, W # 0141, two-component acrylic silicone emulsion main agent, solid content) 50 wt% concentration, pH 7-8,
12 g of average particle diameter 215 nm and the above photocatalyst slurry (photocatalyst prepared by the above method ([Example 1] TiO 2
₂ : Ca (Zr _0.95 Y _0.05 ) O _3- δ (weight ratio 80: 2
0), [Example 2] 50 g of TiO ₂ : CaZrO ₃ δ (concentration 10 wt% of 90:10 by weight) was stirred for 1 minute to prepare a coating material.

SMC (Sheet mold) which is a FRP molding material
A floor pan sample (20 cm square) made of a ing compound, an unsaturated polyester resin, a filler, and a glass fiber) was washed with water, degreased with isopropanol, and then the photocatalyst paint was applied. 1 hour at room temperature after application (room temperature 2
When cured at 8 ° C., it was cured at room temperature to obtain an antibacterial photocatalytic coating film having a photocatalyst concentration of 50 wt% with respect to the solid content.

A cross-cut peeling test was conducted on each coating film.
There was no peeling at 00/100. No peeling of the coating was observed when rubbed with a dry Kimwipe.
No change in appearance was observed even after leaving 1% NaOH dropwise for 24 hours. No change in appearance was observed even after immersion in 60 ° C. hot water for 24 hours.

[0065]

Comparative Example Titanium oxide photocatalyst secondary processed product (photocatalyst manufactured by Ishihara Sangyo, ST-K03, inorganic coating agent, solid content concentration 10% (normal dry type), titania / silicate ratio 50/5
0, main application: antibacterial, antifouling FRP molding material SMC (Sh
A floor pan sample (20 cm square) of an eet molding compound, a sheet-shaped molding material composed of an unsaturated polyester resin, a filler, and a glass fiber was washed with water and degreased with isopropanol, and then the above copper-supported photocatalytic paint was applied. It is 0/100 when cross-cut peeling test is performed after heating and drying at 150 ° C for 30 minutes.
Completely peeled off. Also, the film was dissolved after 1% NaOH was dropped and left for 1 hour. Also, after being immersed in warm water at 60 ° C. for 24 hours, the film below the water line was completely peeled off.

In addition, the above spectrophotometer (U, manufactured by Hitachi Ltd.)
(4000 spectrophotometer), the light absorption spectrum of each coating film was measured by the diffuse reflection method, and the state of light absorption in the visible light region of the sample was examined. Since the diffuse reflectance of the photocatalysts according to Examples 1 and 2 with respect to the visible light having the wavelength λ> 420 nm is lower than the diffuse reflectance of the photocatalyst according to the comparative example, in the visible light range of the photocatalyst according to the example. It has been confirmed that the light absorption of is superior to that of the photocatalyst according to the comparative example.

[0067]

INDUSTRIAL APPLICABILITY The antibacterial photocatalyst paint and coating film of the present invention have excellent photocatalytic performance by using an inexpensive composite oxide photocatalyst that exhibits photocatalytic activity based on a simple new mechanism in the visible light region. Since it has no solvent and is environmentally friendly, it is easy to work even in the case of construction. By using a silicone acrylic emulsion paint that is a composite of polyorganosiloxane and acrylic polymer, film strength (film forming property) It also has the functions of both polymers: weather resistance and water repellency. Therefore, the coating film formed by applying the antibacterial photocatalyst coating is excellent in hot water resistance and alkali resistance. .

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takahisa Omata             2-1 Yamadaoka, Suita City, Osaka Prefecture Osaka University             Graduate School of Engineering F-term (reference) 4G069 AA03 AA08 BA04B BA22B                       BA48A BB06A BB06B BC09B                       BC40B BC51B CA11 EA08                       FB23                 4J038 CG001 DL031 HA216 KA04                       MA08

Claims (6)

[Claims] 1. An antibacterial photocatalyst paint containing a silicone acrylic emulsion paint, an aqueous solvent and a photocatalyst, wherein the photocatalysts have photocatalytic properties with each other, and the bottom of the conduction band in the energy band structure based on the vacuum level is formed. Oxide semiconductors (I) and (II) having different electron energy levels and electron energy levels at the top of the valence band
An antibacterial photocatalyst paint characterized by being composed of an oxide composite having a joint part according to, and at least the oxide semiconductor (I) having photocatalytic properties even in the visible light range. 2. The antibacterial photocatalyst paint according to claim 1, wherein the silicone-acrylic emulsion paint containing the photocatalyst is a composite of polyorganosiloxane and acrylic polymer. 3. The antibacterial photocatalyst paint according to claim 1, wherein the paint containing the photocatalyst is a room temperature cross-linking type paint. 4. The photocatalyst comprises an oxide semiconductor (I),
Composition formula (III) A_{2 -X}B_{2 + X}O_8-2δ (however, -0.4 <X
<+0.6 and -0.5 <2δ <+0.5)
A and B ions that can have multiple valences
Composition formula (IV) A with regular arrangement_2-X ³⁺B_{2 + X} ⁴⁺O
_{7+ (X / 2) + Y}(However, -0.4 <X <+0.6, and-
0.2 <Y <+0.2) pyrochlore type oxide fluorite
Oxygen deficiency position or interstitial position is less seen from the mold structure
Pyrochlore related structure with oxygen ion inserted in one side
The oxide semiconductor (II) is composed of an oxide
Type or anatase type or a mixture of these two types
Titanium oxide, zinc oxide, tin oxide, zirconium oxide
System or strontium titanate
The antibacterial photocatalyst paint according to claim 1, which is a characteristic. 5. The antibacterial photocatalyst coating composition according to claim 1, wherein the photocatalyst carries an antibacterial metal. 6. An antibacterial photocatalytic member, characterized in that the antibacterial photocatalytic coating composition according to any one of claims 1 to 5 is applied to a substrate and cured to form an antibacterial photocatalytic film.