JP2006131583A - Antibacterial property imparting agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an antibacterial property imparting agent which shows a high antibacterial activity with the light of a daylight white fluorescent lamp used for normal illumination, indoors where ultraviolet light is not enough. <P>SOLUTION: The antibacterial property imparting agent contains a titanium dioxide complex produced from titanium dioxide and an acidic substance and/or its salt. The titanium dioxide complex is obtained by impregnating, adsorbing, or mixing titanium dioxide with the acidic substance and/or its salt; or coprecipitating a water solution of a titanium compound and a water solution of the acidic substance and/or its salt. The acidic substance and/or its salt is selected from the group consisting of sulfuric acid, tungstic acid, ammonium sulfate, titanium sulfate, ammonium tungstate, and titanium tungstate. This antibacterial property imparting agent imparts superior antibacterial property even with the light of the daylight white lamp, or the like, and can remove bacteria of foods and table ware, sterilize medical facilities and medical supplies, and remove bacteria in general rooms. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a titanium dioxide-based antibacterial property-imparting agent having high antibacterial activity. More specifically, the present invention requires a titanium dioxide composite that exhibits excellent antibacterial activity even when irradiated with a light source that is poor in ultraviolet light, such as a day white fluorescent lamp, and more specifically, a day white fluorescent lamp of about 500 to 1000 lux. It is related to the antibacterial property-imparting agent contained as a component of food, and it is applied to various fields such as food, environment, health, and medical care, and is extremely useful for suppressing the growth of bacteria and preventing spoilage. .

In recent years, awareness of the environment and health has improved, and interest in antibacterial and antifungal factors has been increasing in the fields of food, clothing and shelter.
In the field of food, domestic and foreign fresh foods and processed foods are lined up in the supermarket display corner, and the safety of foods is strongly demanded for setting the expiration date and storing them for weekend purchases at home. Although food hygiene management technology has improved year by year, new food poisoning due to O-157 has also occurred. In addition, due to the recent increase in hygiene awareness, products that have been given antibacterial properties not only for food and tableware but also for furniture and clothing have come to be used in the home and various other living environments. ing.
The globalization trend that is rapidly progressing year by year also creates a risk of a severe acute respiratory syndrome (SARS) epidemic in winter. In the medical field, nosocomial infection due to MRSA that lacks effective protective means is still recognized, and thus there is a strong need for antibacterial agents that are effective against these pathogenic bacteria.

  By the way, it has long been known that titanium dioxide has a photocatalytic action and can oxidatively decompose almost any organic compound when irradiated with sunlight. In recent years, it has been used for deodorizing, antibacterial and antifungal properties utilizing such properties of titanium dioxide. Application to applications is being studied. However, the action of titanium dioxide is a phenomenon that is exhibited when irradiated with ultraviolet-rich sunlight, mercury lamps, etc., and it has been sufficient in the past when indoors with poor ultraviolet light or when using daylight white fluorescent light. It was difficult to obtain antibacterial and antifungal effects.

  In order to use the photocatalytic action of titanium dioxide indoors where ultraviolet light is poor, for example, under a daylight fluorescent lamp, it is necessary to further enhance the photocatalytic action of titanium dioxide. A number of proposals have already been made regarding the high activation of such a titanium dioxide photocatalyst. As one of the effective means, a crystal system of titanium dioxide, a degree of crystallinity, or a method of increasing the specific surface area by making titanium dioxide porous has been proposed. Specifically, anatase titanium dioxide with excellent photocatalytic activity in titanium dioxide is formed on a substrate by chemical vapor deposition and baked at 500 to 900 ° C. to increase the anatase crystallinity and photocatalytic activity. (Refer to Patent Document 1), titanium alkoxide is applied to porous ceramic and fired to form a microporous film to increase photoactivity (refer to Patent Document 2), and the crystal structure of titanium dioxide is conical. A method of forming a mold or a columnar structure (see Patent Documents 3 and 4), a method of hollowing out the columnar structure to increase the contact area and photoactivation (refer to Patent Document 5), and further, sputtering of titanium dioxide on the substrate. A series of proposals relating to photocatalytic activation has been made, such as a method of forming and laminating a film to increase the catalytic ability (see Patent Document 6). However, the evaluation of photocatalytic activity in these patents is for chemical substances such as acetaldehyde, using xenon lamps rich in ultraviolet rays similar to sunlight, germicidal lamps, blacklights, etc. It was not intended to activate a photocatalyst effective for a light source of a fluorescent lamp level, and its activation effect was insufficient.

  As another means for activating the photocatalytic activity in titanium dioxide, a series of proposals using a noble metal in combination with titanium dioxide has been made. Specifically, platinum, palladium, gold, etc. are supported on the surface of titanium dioxide columnar crystals to increase the photocatalytic activity (see Patent Document 7), and platinum, etc. are supported on rutile titanium oxide in the form of fine particles. For example, a method for improving the activity (see Patent Document 8) and a method for increasing the activity by adding yttrium to titanium oxide (see Patent Document 9) have been proposed. As a special method, a method of obtaining a highly active photocatalyst by supporting a noble metal such as iridium on barium titanate (see Patent Document 10) has been proposed. These proposals are often evaluated by evaluating the decomposability of compounds such as acetaldehyde, or using mercury-rich lamps that are rich in ultraviolet rays as the light source, or using sunlight directly as the light source. It is not intended to be used indoors.

When the platinum catalyst is supported on the rutile type titanium dioxide described in Patent Document 8, the rutile type titanium dioxide is excited by light up to a wavelength of 407 nm (band gap 3.05 eV), and anatase type titanium dioxide. The wavelength of photoexcitation from 388 nm (band gap 3.20 eV) is on the visible light side (long wavelength), and the effect of activation of platinum particles is added. In the book. However, noble metals such as platinum are remarkably expensive as compared with titanium oxide, and practical limitations cannot be avoided in terms of cost.
As described above, most of the conventional methods for activating the photocatalytic action of titanium dioxide are intended for light sources rich in ultraviolet rays such as sunlight and black light, and the effect of photoactivation is several times as much. The photoactive effect was insufficient for use indoors or under the light of daylight white fluorescent lamps.

JP 2000-266902 A (pages 1 to 5) JP 2001-259435 A (pages 1 to 5) JP 2002-253974 A (pages 1-7) JP 2002-370034 A (pages 1-7) JP2003-190810A (pages 1-7) JP-A-11-47609 (pages 1-7) JP 2003-299965 A (pages 1 to 11) JP 2000-262906 A (pages 1 to 10) JP 11-244706 A (pages 1 to 4) JP-A-9-253486 (pages 1-7) K. Tanabe, M. Misono, Y. Ono, H. Hattori, New solid acids and bases, 1-25, 47-60, Elsevier (1989). Kozo Tabe, Ryoji Noyori, Super Strong Acid / Super Base, 1-22, Kodansha Scientific (1980). K.Dalai, R. Sethuraman, S. P. R. Katikaneni, R. O. Idem, Ind .. Eng. Chem. Res. 37, 3869-3878 (1998). Makoto Hino, Kazushi Arata, Surface, 34-2, 51-61 (1996) Supervised by Kazuhito Hashimoto and Akira Fujishima, All of Photocatalyst, 219-221, Industrial Research Committee (2003) Tetsuro Kiyoyama, “Metal Oxides and Their Catalysis”, Kodansha Scientific (1980) Satoshi Ozaki et al., “Catalyst Preparation Chemistry”, p. 49, Kodansha Scientific (1980) "The 9th Catalysis School Text" sponsored by the Catalysis Society of Japan, P52, Catalysis Society of Japan (1998)

  An object of the present invention is to provide an antibacterial property-imparting agent using a titanium dioxide composite exhibiting high antibacterial activity, not only under sunlight rich in ultraviolet rays, but also indoors where ultraviolet rays are scarce. is there. Furthermore, if it mentions further, it aims at provision of the antibacterial property imparting agent which shows an effective antibacterial activity under the light of the daylight white fluorescent lamp used for normal illumination indoors.

  In view of the above situation, the present inventors have conducted extensive research on an antibacterial property-imparting agent having excellent antibacterial activity indoors where ultraviolet light is scarce, and as a result, titanium dioxide exhibiting high activity when irradiated with daylight white fluorescent lamps. The complex was found and the present invention was completed.

That is, the gist of the present invention is as follows.
(1) An antibacterial property-imparting agent using a titanium dioxide complex produced from titanium dioxide and an acidic substance and / or a salt thereof.
(2) The antibacterial property-imparting agent according to (1), wherein the titanium dioxide composite exhibits high antibacterial properties by irradiation with a daylight fluorescent lamp having an illuminance of 2000 lux or less and poor in ultraviolet light.
(3) A titanium dioxide composite is obtained by impregnating, adsorbing, or mixing titanium dioxide with an acidic substance and / or a salt thereof, or coprecipitation of an aqueous solution of a titanium compound and an acidic substance and / or a salt thereof. The antibacterial property imparting agent according to (1) or (2) above, wherein
(4) The acidic substance is represented by the following general formula (I)
H ₂ XO ₄ (I)
[Wherein, X represents a sulfur atom or a tungsten atom. ]
The antibacterial property imparting agent according to any one of the above (1) to (3), which is a substance represented by
(5) Titanium dioxide has an anatase type or rutile type crystal structure, or a mixed crystal structure of anatase type and rutile type, according to any one of the above (1) to (4), Antibacterial agent.
(6) The acid substance is one or more substances selected from the group consisting of sulfuric acid, tungstic acid, and anhydrides thereof. The antibacterial property imparting agent described.
(7) The above-mentioned (1) to (6), wherein the salt of the acidic substance is one or more substances selected from the group consisting of ammonium sulfate, titanium sulfate, ammonium tungstate, and titanium tungstate. The antibacterial property imparting agent according to any one of the above.

The antibacterial property-imparting agent of the present invention has an excellent antibacterial activity even in the light of a daylight white fluorescent lamp used for indoor lighting or the like. Therefore, if the antibacterial property-imparting agent of the present invention is used, it is not necessary to irradiate sunlight or ultraviolet lamp light containing ultraviolet rays, sterilizing foods and dishes, sterilizing medical facilities and medical supplies, general indoors Thus, it is possible to obtain a state free from bacteria such as Escherichia coli and mold by irradiation with light for indoor lighting such as a white fluorescent lamp.
In addition, if supplemented, the titanium dioxide composite used in the present invention exhibits high antibacterial properties even in a light source that is poor in ultraviolet rays, but is more highly activated in sunlight with a lot of ultraviolet rays or light from a mercury lamp. The antibacterial property-imparting agent of the present invention using a composite exhibits stronger antibacterial properties under sunlight with a lot of ultraviolet rays or light from a mercury lamp.

The titanium dioxide composite which is an essential component constituting the antibacterial property imparting agent of the present invention is formed from titanium dioxide and an acidic substance and / or a salt thereof. Specifically, components of acidic substance and / or salt thereof obtained by impregnation, adsorption, coprecipitation or mixing treatment with titanium dioxide and acidic substance and / or salt thereof, and then drying and baking as necessary. It is a titanium dioxide composite in which elements are integrally combined on the surface or inside of titanium dioxide particles.
The structure and mechanism of the titanium dioxide composite used in the antibacterial property-imparting agent of the present invention is not necessarily clear. However, for example, sulfuric acid caused by acidic substances and / or salts thereof on the surface or inside of titanium dioxide particles. Roots, tungstates, ammonia groups, or composites containing titanium oxide, titanium sulfate, tungsten oxide, tungsten sulfate, etc. are formed. At the same time, holes are generated and the photocatalytic effect is more strongly manifested.As a result, it is fully activated even with weak light energy such as indoor lighting light such as daylight white fluorescent lamp, and has excellent antibacterial activity It is thought that it demonstrates.

  Sulfuric acid mentioned as one of the acidic substances used in the present invention is known to form a solid acid with high affinity with titanium oxide (see Non-Patent Documents 1 and 2), and a metal oxide is used as a catalyst. It has been pointed out that sulfuric acid generates a solid acid with titanium oxide to increase the catalytic activity in a high-temperature gas phase catalytic isomerization reaction of an aliphatic hydrocarbon (see Non-Patent Document 3). The present inventors pay attention to these phenomena, and in the process of investigating the characteristics of the composite of titanium oxide / sulfuric acid in detail, they found a phenomenon in which ethylene having a carbon / carbon double bond is very easily decomposed by a photocatalyst at room temperature. The present inventors have found that the complex can be a highly active photocatalyst. In addition, from the surrounding investigations on solid acids, tungstic acid has the same effect (Non-Patent Document 4). Surprisingly, a highly active photocatalyst is formed even in a composite of titanium oxide and titanium sulfate, and ammonium sulfate. It was also found that a highly active photocatalyst is formed even in combination with. The present invention provides an excellent antibacterial property-imparting agent by utilizing such a titanium dioxide composite having high photocatalytic activity.

The raw material titanium dioxide (TiO ₂ ) used in the present invention may be any of anatase type, rutile type or brookite type crystal type, or amorphous type, but anatase type, rutile type, or a mixture of these crystals. Structures are preferred, and anatase-type titanium dioxide is particularly preferred. Their particle size can be from about 1 nm (10 ⁻⁹ m) to about 1 μm (10 ⁻⁶ m), more preferably from 3 nm (3 × 10 ⁻⁹ m) to 0.1 μm (10 ⁻⁵ m). In general), but those having a small particle size are preferred. Desirably, titanium dioxide granulated into a particle having a diameter of about 1 mm may be used. A specific surface area of about 5 m ² / g to 400 m ² / g, preferably 50 m ² / g to 390 m ² / g can be used, but one having a relatively large value is suitable. The titanium dioxide used in the present invention can be used as a raw material as it is marketed as a product. However, if desired, hydrolysis of titanium salts such as titanium salts of inorganic acids such as titanium sulfate, titanium tetrachloride and titanium nitrate, or titanium tetraethoxide, titanium tetraisopropoxide or titanium tetra (2-ethylhexanoate) Or it can also prepare by methods, such as neutralization, precipitation, and baking, with basic substances, such as caustic soda. Of the above, anatase titanium dioxide is sold as a photocatalyst.

  Representative products of commercially available anatase titanium dioxide include AMT-100, AMT-600, JA-1, manufactured by Teika Co., Ltd., SSP-25, A-110, CSPM, CSB manufactured by Sakai Chemical Industry Co., Ltd. ST01 and ST-41 manufactured by Ishihara Sangyo Co., Ltd. are known, and titanium dioxide composites can be prepared using these titanium dioxides. Moreover, it is a mixed crystal type product of MT-150A, MT-500B, MT-600B, JR, CR-EL made by Ishihara Sangyo Co., Ltd., anatase and rutile, which are commercially available rutile titanium dioxide products. Showa Titanium F6 may be used.

The acidic substance used in the present invention is preferably an inorganic acid represented by the general formula (I), and particularly preferably sulfuric acid, tungstic acid, or an anhydride thereof. The salt of the acidic substance is an ammonium salt or a titanium salt of such an acidic substance, preferably titanium sulfate, ammonium sulfate, ammonium tungstate, or titanium tungstate. An acidic substance other than these substances or a salt thereof does not necessarily show a sufficiently satisfactory improvement in antibacterial activity. For example, when hydrochloric acid, nitric acid, or molybdic acid is used as an acidic substance, it cannot be decomposed or evaporated during firing to obtain a stable and effective composite with titanium dioxide.
Among these acidic substances, sulfuric acid and its ammonium salt and titanium salt are preferable, and ammonium sulfate exhibits particularly excellent antibacterial activity. However, even with the same sulfate, sulfates such as sodium sulfate and lithium sulfate do not show such good antibacterial activity.

  It is said that the action mechanism of the antibacterial effect of the titanium dioxide photocatalyst that is irradiated with sunlight and activated by the ultraviolet rays varies depending on the type of bacteria. In other words, in the case of bacteria with outer membranes such as Escherichia coli, which is a gram-negative bacterium, the first step is a partial degradation of the outer membrane, which is a cell wall component, and the second step is a two-step mechanism by structural changes and functional destruction of the cytoplasmic membrane. In the case of Gram-positive bacteria, yeast, etc., it consists of a single-step mechanism due to structural changes and functional destruction of the cytoplasmic membrane (see Non-Patent Document 5). Although the antibacterial effect of titanium dioxide varies depending on the type of bacteria and yeast, it is generally said that the final decomposition progresses to carbon dioxide and water, and exhibits antibacterial action. As a result of the antibacterial test, the antibacterial property-imparting agent of the present invention consisting of a titanium dioxide composite has a result showing excellent antibacterial properties such that Escherichia coli is not detected only by short-time irradiation of a daylight fluorescent lamp of about 500 to 1000 lux From the obtained results, it is considered that the same effect is shown not only on bacteria but also on yeasts, molds and viruses.

  The antibacterial property-imparting agent of the present invention comprises, as an essential component, a titanium dioxide composite obtained by impregnating titanium dioxide with an acidic substance and / or salt of the acidic substance, followed by drying and baking. The imparting agent is not limited to ultraviolet rays rich in ultraviolet rays, light sources having poor ultraviolet rays, for example, irradiation of light from daylight white fluorescent lamps used for ordinary illumination, etc., further mentioning about 500 to 1000 lux. High antibacterial properties when irradiated with daylight fluorescent lamps at room temperature.

A commercially available daylight white fluorescent lamp can be used as the light source, but the antibacterial property imparting agent comprising the titanium dioxide composite of the present invention has a very high photocatalytic activity. In addition, sufficient antibacterial performance is exhibited at an illuminance of 2000 lux or less, and further 1000 lux or less. In the case of performing irradiation for a long time, low illuminance, for example, 250 lux or less can be put to practical use. If desired, a light source such as a light emitting diode may be used.
However, it does not preclude the use of UV-rich sunlight if specifically desired. In that case, high antibacterial properties can be obtained, but attention must be paid to the selection and consideration of damage to surrounding substrates.

  The antibacterial property-imparting agent of the present invention can be used alone, but in the case where it is used by supporting it on a plastic substrate such as an organic material such as polyethylene, a surface of the antibacterial property-imparting agent is coated with a silica material in advance. An effective method for preventing deterioration of the substrate can be taken by a method such as encapsulation with a silane coupling agent or the like. Moreover, you may process and use the antibacterial property imparting agent of this invention processed into the film form and fiber shape which carry | supported to the plastic. Further, it may be applied to an inorganic material such as tile, concrete or stone, or may be coated in a thin film shape, or may be used in a partially adhered shape. Further, it may be used in the form of paper, non-woven fabric, or filter.

Next, the manufacturing method of the titanium dioxide composite used for the antibacterial property imparting agent of this invention is demonstrated.
The titanium dioxide composite used in the present invention is usually prepared by an impregnation method, but in some cases, a coprecipitation method may be used (see Non-Patent Documents 6 to 8). In the impregnation method, titanium dioxide is generally impregnated with an acidic substance and / or a salt thereof, dried at a temperature of about 20 to 200 ° C., fired at a temperature of 300 to 700 ° C. and then pulverized. Specifically, when the acidic substance is sulfuric acid, it is prepared by impregnating or adsorbing sulfuric acid on titanium dioxide. That is, a sulfuric acid aqueous solution having a concentration of about 0.1 to 20% by mass is diluted and added to commercially available titanium dioxide, mixed well and homogenized, and sulfuric acid is impregnated or adsorbed on titanium dioxide. After drying and baking at a temperature, the titanium dioxide composite may be prepared by pulverization. In addition, as another method for preparing a titanium dioxide composite, sulfuric acid is added to ilmenite ore containing titanium dioxide and iron oxides as the main components to form titanium sulfate, and the uniform solution is converted to titanium hydroxide by hydrolysis, resulting in a difference in solubility. To remove iron sulfate. In this process, since titanium dioxide is known to have a strong affinity for sulfate radicals, a form in which sulfate radicals are left when obtaining titanium dioxide may be used as it is as a titanium dioxide composite. The amount of sulfate radicals contained in titanium dioxide is usually about 1 to 20 mol%, preferably about 2 to 15 mol% with respect to titanium dioxide. At 1 mol% or less, the increase in activity is small, and at 20 mol% or more, the photocatalytic activity tends to decrease, and depending on the application, there is a concern that problems such as elution of sulfate radicals may occur. It is not preferable. However, it does not preclude the use of an amount of 20 mol% or more if specifically desired. In addition, in the said commercially available titanium dioxide, since CSPM by Sakai Chemical Industry Co., Ltd. contains a sulfate radical, it is also possible to omit an impregnation process and to use it as it is.

  In addition, as a method of preparing a titanium dioxide composite by coprecipitation method, a commercially available titanium sulfate is neutralized with sodium hydroxide or aqueous ammonia to precipitate titanium dioxide, and the sulfate radical remains in the precipitate. It is also possible to use it after filtering, heat drying, firing and grinding. Further, the titanium dioxide containing sulfuric acid as the acidic substance includes those whose chemical structure has changed due to thermal decomposition or the like in various processes such as washing, drying by heating, baking and pulverization.

When the acidic substance is tungstic acid, a method of impregnating or adsorbing tungstic acid into titanium dioxide in the form of a solution, a method of coprecipitation of an aqueous solution of a titanium compound such as a titanium salt of an inorganic acid and the tungstic acid solution, If particularly desired, a method of mixing titanium dioxide and the fine powder of tungstic acid is possible. In the case of impregnation or adsorption, the titanium dioxide powder and the tungstic acid solution are mixed well to homogenize and impregnate or adsorb the tungstic acid to the titanium dioxide, and then dried and fired at a temperature of about 20 to 200 ° C. for several hours. The titanium dioxide containing tungstic acid may be prepared by pulverization. The amount of tungstic acid contained in the titanium dioxide is usually about 1 to 20 mol%, preferably about 2 to 15 mol%, relative to titanium dioxide. Since the activity is small at 1 mol% or less and the photocatalytic activity tends to decrease at 20 mol% or more, it is usually preferable to limit the amount to 20 mol% or less. However, it does not preclude the use of an amount of 20 mol% or more if specifically desired. As tungstic acid, there is a commercially available yellow type (WO ₃ · H ₂ O = H ₂ WO ₄ ), but it is almost insoluble in water (solubility = about 3.75 mg / l) and soluble in aqueous ammonia and hydrofluoric acid. To do. Further, metatungstic acid H ₆ [H ₂ W ₁₂ O ₄₀ ] is soluble in water, so that it can be impregnated, adsorbed and coprecipitated. Moreover, as the titanium dioxide composite containing tungstic acid used in the present invention, in addition to those obtained by impregnation, adsorption, coprecipitation, or mixing as described above, a titanium dioxide composite containing these tungsten compounds is used. Furthermore, after that, chemical structure changes caused by thermal decomposition in various processes such as washing, heat drying, baking, and pulverization are included.

In the case where a titanium dioxide composite is prepared using a salt of an acidic substance, and the salt of the acidic substance is ammonium sulfate, a method of impregnating or adsorbing ammonium sulfate in the form of a solution with titanium sulfate, a titanium salt of an inorganic acid For example, a method of co-precipitation of an aqueous solution of the above and the aqueous solution of ammonium sulfate, and a method of simply mixing titanium dioxide and the above ammonium sulfate can be used. When impregnating or adsorbing, titanium dioxide and ammonium sulfate aqueous solution are mixed well to equalize, and ammonium sulfate is impregnated or adsorbed on titanium dioxide, dried and fired at a temperature of about 20 to 200 ° C., and then pulverized to obtain ammonium sulfate. What is necessary is just to prepare the titanium dioxide composite containing.
In the case of coprecipitation, a commercially available aqueous solution of titanium sulfate and an aqueous solution of ammonium sulfate are mixed and neutralized with an aqueous sodium hydroxide solution or aqueous ammonia to produce titanium dioxide containing ammonium sulfate by coprecipitation, followed by filtration and washing. The powder obtained in this manner may be dried and fired at a temperature of about 20 to 200 ° C. and then pulverized to prepare titanium dioxide containing ammonium sulfate.

  The amount of ammonium sulfate contained in titanium dioxide is usually about 1 to 20 mol%, preferably about 2 to 15 mol%, relative to titanium dioxide. If it is 1 mol% or less, the activity is small, and if it is 20 mol% or more, the photocatalytic activity tends to decrease. Therefore, it is usually preferable to limit the amount to 20 mol% or less. However, it does not preclude the use of an amount of 20 mol% or more if specifically desired. Moreover, as titanium dioxide containing ammonium sulfate used in the present invention, in addition to those obtained by impregnation, adsorption, coprecipitation, or mixing as described above, titanium dioxide containing ammonium sulfate is further washed and heated. Also included are those that have undergone chemical structural changes due to thermal decomposition in various processes such as drying, firing, and pulverization.

  When the salt of the acidic substance is titanium sulfate, it is prepared by impregnating or adsorbing titanium sulfate on titanium dioxide. That is, a commercially available titanium dioxide (IV) solution is diluted with commercially available titanium dioxide in an aqueous solution of about 0.1 to 20% by mass, mixed well, and homogenized to impregnate or adsorb titanium sulfate to titanium dioxide. The titanium dioxide composite containing titanium sulfate may be prepared by drying at a temperature of about 20 to 200 ° C. for several hours, firing, and then pulverizing. The amount of titanium sulfate impregnated in titanium dioxide is usually about 1 to 20 mol%, preferably about 2 to 15 mol%, relative to titanium dioxide. If it is 1 mol% or less, the activity is small, and if it is 20 mol% or more, the photocatalytic activity tends to decrease. Therefore, it is usually preferable to limit the amount to 20 mol% or less. However, it does not preclude the use of more than 20 mol% if specifically desired. Furthermore, after that, chemical structure changes caused by thermal decomposition in various processes such as washing, heat drying, baking, and pulverization are included.

  In the case where the acidic substance is ammonium tungstate, a method of impregnating or adsorbing titanium dioxide in the form of a solution, which is a compound containing tungsten trioxide and dissolved in water or aqueous ammonia, titanium salt of inorganic acid, etc. A method of co-precipitation of an aqueous solution and an aqueous solution of a compound containing tungstic acid or tungsten trioxide, and a method of mixing titanium dioxide and a fine powder of a compound containing tungstic acid or tungsten trioxide can be used if desired. . Examples of the compound containing tungsten trioxide and dissolved in water or ammonia water include ammonium tungstate parapentahydrate and ammonium metatungstate. When impregnating or adsorbing, a compound containing tungstic acid or a compound containing tungsten trioxide, which is dissolved in water or aqueous ammonia and mixed with titanium dioxide and mixed uniformly with an aqueous ammonia solution, and containing ammonium tungstate. The titanium dioxide containing ammonium tungstate may be prepared by impregnating or adsorbing to titanium dioxide, drying at a temperature of about 20 to 100 ° C., firing, and then pulverizing.

  The amount of ammonium tungstate to be contained in titanium dioxide is usually about 1 to 20 mol%, preferably about 2 to 15 mol% with respect to titanium dioxide. If it is 1 mol% or less, the activity is small, and if it is 20 mol% or more, the photocatalytic activity tends to decrease. Therefore, it is usually preferable to limit the amount to 20 mol% or less. However, it does not preclude the use of more than 20 mol% if specifically desired. Moreover, as titanium dioxide containing tungsten component used in the present invention, in addition to those obtained by impregnation, adsorption, coprecipitation, or mixing as described above, titanium dioxide containing these tungsten components is further washed. In addition, those in which chemical structure changes are caused by thermal decomposition in various processes such as heat drying, baking, and grinding.

When the acidic substance is titanium tungstate, it is prepared by coprecipitation from an aqueous solution of titanium sulfate and a solution of a compound containing tungsten trioxide and dissolved in water or aqueous ammonia. That is, a commercially available titanium sulfate aqueous solution and a compound solution containing tungsten trioxide and dissolved in water or aqueous ammonia are mixed, neutralized with aqueous sodium hydroxide or aqueous ammonia, and a titanium dioxide composite containing titanium tungstate. May be produced by coprecipitation, and then the powder obtained by filtration and washing may be dried and fired at a temperature of about 20 to 200 ° C. and then pulverized to prepare a titanium dioxide composite. Alternatively, an aqueous solution of tungstic acid is uniformly mixed with metatitanic acid [TiO (OH) ₂ ], evaporated and dried, and then baked, and titanium dioxide (anatase) generated from metatitanic acid is reacted with metatitanic acid and tungstic acids The resulting titanium tungstate may be impregnated and supported. The tungsten acids, tungstic acid _[H 2 _WO 4], ammonium paratungstate para pentahydrate _{[(NH 4) 10 W 12} O 41 · 5H 2 O], ammonium metatungstate _{[(NH 4)} 6 ₍ H ₂ W ₁₂ O ₄₀ )] and the like can be used. Furthermore, a commercially available titanium dioxide, metatitanic acid and tungstic acid solution is uniformly mixed, dried and fired to impregnate the commercially available titanium dioxide with titanium tungstate produced by the reaction of metatitanic acid and tungstic acid, and then pulverized. May be.

  The amount of titanium tungstate to be contained in titanium dioxide is usually about 1 to 20 mol%, preferably about 2 to 15 mol% with respect to titanium dioxide. If it is 1 mol% or less, the activity is small, and if it is 20 mol% or more, the photocatalytic activity tends to decrease. Therefore, it is usually preferable to limit the amount to 20 mol% or less. However, it does not preclude the use of an amount of 20 mol% or more if specifically desired. Furthermore, after that, chemical structure changes caused by thermal decomposition in various processes such as washing, heat drying, baking, and pulverization are included.

  Preparation of the above-mentioned titanium dioxide composite containing tungstic acid, ammonium sulfate, and ammonium tungstate by impregnation or adsorption can be performed with reference to methods described in various documents. The usual method is to impregnate or adsorb titanium dioxide, ammonium sulfate, and ammonium tungstate solution into titanium dioxide, and impregnate or adsorb the heat-dried, baked, or pulverized part or all of the steps. It is prepared through the process. (For example, refer nonpatent literature 4 and 5.). In addition, the above-mentioned tungstic acid, ammonium sulfate, and titanium dioxide impregnated or adsorbed with ammonium tungstate are usually soluble at a temperature of 20 to 200 ° C. in the case of tungstic acid and ammonium sulfate, and water soluble in the case of ammonium tungstate. In the case of the one having a low solubility even with hot water such as ammonium tungstate parapentahydrate at 20 to 200 ° C., it is uniformly mixed and dried using a slightly large amount of hot water. The obtained lump is pulverized and then fired at a temperature of 300 to 700 ° C., preferably at a temperature of 300 to 600 ° C. for about 3 to 6 hours, so as not to cause a change in the crystal structure of titanium dioxide. Take care.

  The preparation of the titanium dioxide composite by coprecipitation can also be carried out with reference to the methods described in the literature (see, for example, Non-Patent Document 4 or 5). As a general method, a solution of the above-mentioned tungstic acid, ammonium sulfate, and ammonium tungstate and a solution of a titanium compound are prepared in advance, and a solution obtained by mixing these two with stirring is mixed with a basic compound such as caustic soda. Add aqueous solution to coprecipitate in the above mixed solution or generate coprecipitate by hydrolysis, and this precipitate is subjected to some or all of the steps such as heat drying, baking, pulverization, etc. Titanium dioxide composite Can be prepared. Heat drying is usually performed in a temperature range of about 20 to 200 ° C., and is usually fired at 300 to 700 ° C. and pulverized. Here, examples of the titanium compound include titanium salts of inorganic acids such as titanium tetrachloride and titanium sulfate, and the above titanium alkoxides. As a simpler and more practical method of coprecipitation, fine particles of titanium dioxide are previously dispersed in water, an aqueous solution of ammonium sulfate and ammonium tungstate is added thereto, and a strong base such as caustic soda is added dropwise with stirring. In this way, a titanium dioxide composite having a uniform and high specific surface area can be obtained.

  The antibacterial property-imparting agent of the present invention using the titanium dioxide composite obtained by the method as described above exhibits excellent antibacterial property even with light of a white fluorescent lamp for indoor lighting. It is extremely effective for antibacterial, antifungal, and virus in various fields such as medicine. This antibacterial property-imparting agent may be used as it is, but it is stabilized by a silica treatment or a silane coupling agent and supported on plastic films, molded products, paper, sheets, organic and / or inorganic fiber products, and filters. However, it can be used in various forms or as a coating agent.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to the Example shown below. In the examples, “%” and “part” are based on mass unless otherwise noted.

1.1 Preparation of Titanium Dioxide Complex (1-2) by Impregnation with Sulfuric Acid White Titanium Dioxide AMT-100 {(1-1), Specific Surface Area 260 m ² / g with Anatase Type Crystal Structure Provided by Teika Co., Ltd. } In a magnetic petri dish, and then a uniform solution of 2.1 g (10 mmol, 8 mol% relative to titanium dioxide) of a 47 wt% sulfuric acid aqueous solution and 10 mL of water manufactured by Wako Pure Chemical Industries, Ltd. Was added and thoroughly mixed to impregnate with sulfuric acid, and then dried at about 80 ° C. for 1 hour. Next, after firing in a muffle furnace at 400 ° C. for 3 hours and cooling, pulverized titanium dioxide composite (1-2) containing sulfate radicals (MW: 79.9, sulfate radicals are not included in the calculation of molecular weight). 0.9 g (yield: 90.0%) was obtained. The titanium dioxide composite (1-2) containing sulfate radicals was confirmed to have an anatase type crystal structure from the measurement result of an X-ray diffractometer (XRD). The X-ray diffractometer (XRD) used was a fully automatic diffractometer, MXP ^3A , manufactured by Mac Science. In the following Examples and Comparative Examples, the same machine was used for all X-ray diffraction measurements.

1.2 Preparation of Petri dish with Titanium Dioxide Complex (1-2) and Determination of Installation Position in Irradiation Box The fungus-containing water for the evaluation of antibacterial properties is water collected in Teganuma, Chiba Prefecture (hereinafter referred to as “raw water”) Sometimes used). 0.15 g of the titanium dioxide composite (1-2) powder obtained in 1.1 above was placed in a glass petri dish having an inner diameter of 92 mm, and 15.0 g of raw water was added to obtain a uniform suspension.
Next, half of the center of one 20-watt daylight fluorescent lamp (FL20SS · EX-N / 18-Z manufactured by Toshiba Lighting & Technology Corporation) is covered with aluminum foil to shield it, and the light emitting part is halved. The position was set at the top of the box and turned on to obtain 500 lux. The illuminance was confirmed with a Minolta illuminometer T-10.
In the following Examples and Comparative Examples, the 20-watt daylight white fluorescent lamp (FL20SS · EX-N / 18-Z manufactured by Toshiba Lighting & Technology Corp., light emitting unit: 1/2) was used as a light source. The spectral energy distribution of this daytime white fluorescent lamp is shown in FIG. As shown in FIG. 1, this day white fluorescent lamp contains almost no light energy in the ultraviolet region with a wavelength of 380 nm or less.

1.3 Measurement of the number of bacteria in water (raw water) containing bacteria The measurement of the number of bacteria in the test water was performed as follows by the method of Shimakyu Bacteria Test Instruments Co., Ltd. According to this method, bacteria can be inspected separately for E. coli and general living bacteria, and the number of bacteria in water can be inspected from both inspection results.
1 mL of raw water was dropped onto an Escherichia coli culture dish of Shimakyu Bacteria Test Instruments Co., Ltd., and the attached sheet was placed on the culture dish and cultured at 35 ° C. for 24 hours in an incubator. The number of colonies of Escherichia coli after the culture was counted and found to be 64 / mL. Moreover, 1 mL was dripped at the general live cell culture dish of Shimakyu Bacteria Test Instruments Co., Ltd., and the attached sheet was put on the culture dish and cultured in an incubator at 35 ° C. for 48 hours. When the number of colonies after the culture was counted, the number of colonies of general viable bacteria was 4460 / mL. The number of colonies is the number of bacteria that survived in the culture dish after culturing. If the number of colonies is expected to be large (approximately 3000 cells / mL or more) as in the case of the above general live bacteria, the bacteria-containing solution is 10 times with sterile water to prepare a 10-fold diluted solution. Then, after culturing with 1 mL, the number of colonies can be counted, and the number obtained by multiplying the counted value by 10 can be used as the number of bacteria.
The method for measuring the number of bacteria is the same as a commonly used method. That is, the number of bacterial bodies (colony) that was enlarged so that one bacterium grew during culture and was visible was measured using a magnifier of about 2.5 times. Since one of the colonies corresponds to the number of bacteria in the test water, the number of colonies is the same as the number of bacteria.

1.4 Fluorescent lamp irradiation of petri dish containing titanium dioxide composite (1-2) 0.15 g of the titanium dioxide composite (1-2) obtained in 1.1 above is put into a glass petri dish with an inner diameter of 92 mm, and 15.0 g of raw water is added. The uniform suspension obtained was used as test water.
The petri dish containing the test water was placed at a position of 500 lux in the irradiation box, and a white white fluorescent lamp was irradiated at an illuminance of 500 lux for 24 hours.

1.5 Measurement of the number of bacteria after irradiation with a fluorescent lamp The antibacterial test was conducted for E. coli and general living bacteria using a test kit manufactured by Shimakyu Bacteria Tester Co., Ltd. That is, in the case of Escherichia coli, 1 mL of the supernatant of the test water after irradiation with the fluorescent lamp obtained in 1.4 above is dropped onto the Escherichia coli culture dish of Shimakyu Bacteria Tester Co., Ltd., and the attached sheet is put on the culture dish. The cells were cultured in an incubator at 35 ° C. for 24 hours. The number of colonies after the culture was counted and found to be 0 / mL. In the case of general viable bacteria, 1 mL of test water after irradiation with a fluorescent lamp is similarly dropped onto the general viable culture dish of Shimakyu Bacteria Test Instruments Co., Ltd. The cells were cultured in an incubator at 48 ° C. for 48 hours. The number of colonies after culture was counted and found to be 0 / mL even in the case of general viable bacteria. These results are shown in Table 1.

Comparative Example 1: Antibacterial Test of Commercially Available Titanium Dioxide Photocatalyst The same titanium dioxide photocatalyst AMT-100 {(1-1), specific surface area 260 m ² / g} manufactured by Teika Co., Ltd. A uniform suspension obtained by adding 15 g to a glass petri dish having an inner diameter of 92 mm and adding 15.0 g of raw water was used as test water. A petri dish containing this suspension with test water was placed at a position of 500 lux in the irradiation box, and a white white fluorescent lamp was irradiated at an illuminance of 500 lux for 24 hours. After completion of the irradiation, 1 mL of the supernatant of the test water in the petri dish was dropped onto the E. coli culture dish of Shimakyu Bacteria Test Instruments Co., Ltd., and the attached sheet was placed on the culture dish and cultured at 35 ° C. for 24 hours in an incubator. The number of colonies after the culture was counted and found to be 10 / mL. In the case of general viable bacteria, 1 mL of test water after irradiation is similarly dropped onto the general viable culture dish of Shimakyu Bacteria Test Instruments Co., Ltd., and the attached sheet is placed on the culture dish for 48 hours at 35 ° C. Cultured in an incubator. When the number of colonies after culturing was counted, the number of colonies of general viable bacteria was 667 / mL. These results are shown in Table 1.

2.1 Preparation of Titanium Dioxide Complex (2-2) by Impregnation with Ammonium Sulfate White Titanium Dioxide AMT-100 {(1-1) with a specific surface area of 260 m ² / g} of 10.0 g (125 mmol) was put in a magnetic petri dish, and then a uniform solution of Wako Pure Chemical Industries, Ltd. ammonium sulfate 1.32 g (10 mmol, 8 mol% with respect to titanium dioxide) and water 10 mL was added. The mixture was thoroughly mixed and impregnated with ammonium sulfate, and then dried at about 80 ° C. for 1 hour. Next, after firing in a muffle furnace at 400 ° C. for 3 hours and cooling, the titanium dioxide composite {TiO ₂ · ((NH ₄ ) ₂ SO ₄ ) _0.08 } (2-2) [MW: 79. 9, ammonium sulfate is not included in the calculation of the molecular weight] to obtain 9.5 g (yield: 83.9%). This titanium dioxide composite (2-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

2.2 Antibacterial test of titanium dioxide composite impregnated with ammonium sulfate (2-2) In the same manner as in Example 1, using a test water containing a titanium dioxide composite impregnated with ammonium sulfate, a day white fluorescent lamp was applied at 500 lux. Antibacterial tests were performed on E. coli and general living bacteria when irradiated for 24 hours. As a result, as shown in Table 1, the number of bacterial colonies after culturing for 48 hours in both cases of Escherichia coli and general viable bacteria was 0 / mL.

3.1 Preparation of Titanium Dioxide Composite Impregnated with Titanium Sulfate (3-2) White Titanium Dioxide AMT-100 {(1-1), specific surface area 260 m ² / g} of 5.0 g (62.6 mmol) in a magnetic petri dish, and then a 30% titanium sulfate (IV) solution [Ti (SO ₄ ) ₂ , MW: 239.99] manufactured by Wako Pure Chemical Industries, Ltd. A homogeneous solution of 4.0 g (5.0 mmol, 8 mol% with respect to titanium dioxide) and 5 mL of water was added, mixed well and impregnated with titanium sulfate, and then dried at about 80 ° C. for 2 hours. Next, after calcination at 400 ° C. for 3 hours in a muffle furnace and cooling, the titanium dioxide composite {TiO ₂ (Ti (SO ₄ ) ₂ ) _0.08 } (3-2) [MW: 79.9] containing pulverized titanium sulfate. And 4.9 g (yield: 79.0%). This titanium dioxide composite (3-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

3.2 Antibacterial test of titanium dioxide composite impregnated with titanium sulfate (3-2) In the same manner as in Example 1, using test water containing titanium dioxide composite impregnated with titanium sulfate (3-2), fluorescence was obtained. Antibacterial tests were carried out for E. coli and general living bacteria when irradiated for 24 hours. As a result, as shown in Table 1, the number of bacterial colonies after culturing for 48 hours in both cases of Escherichia coli and general viable bacteria was 0 / mL.

Comparison of Examples 1 to 3 and Comparative Example 1 Table 1 summarizes the results of the antibacterial tests of Examples 1 to 3 and Comparative Example 1. As can be seen from this table, when the antibacterial property-imparting agent of the present invention using various titanium dioxide composites was added as in Examples 1 to 3, it was used for 24 hours at 500 lux using a neutral white fluorescent lamp. The number of colonies is zero in both cases of E. coli and general live bacteria other than E. coli, and the bacteria are completely killed in both cases of E. coli and general live bacteria even after 48 hours of culture. It was confirmed that On the other hand, when untreated titanium dioxide AMT-100, which is a commercially available photocatalyst, was used, both E. coli and general living bacteria were alive after 48 hours of culture, although it decreased from before the irradiation with the fluorescent lamp. From this comparison, it can be seen that the antibacterial property-imparting agent of the present invention has a remarkable antibacterial action.

4.1 Preparation of Titanium Dioxide Composite Impregnated with Tungstic Acid (4-2) White Titanium Dioxide CSB {(4-1), specific surface area 280 m ² having anatase type crystal structure provided by Sakai Chemical Industry Co., Ltd. / g} of 10.0 g (125 mmol) is put in a magnetic petri dish, and then 2.50 g (10 mmol, 8 mol% with respect to titanium dioxide) of Wako Pure Chemical Industries, Ltd. and Wako Pure Chemical Industries, Ltd. A homogeneous solution of 20 mL of 25% aqueous ammonia was added and mixed well to adsorb tungstic acid, and then dried at about 80 ° C. for 2 hours. Titanium dioxide composite {TiO ₂ · (H ₂ WO ₄ ) _0.08 } (4-2) [MW: 79.9, tungstic acid is baked in a muffle furnace at 500 ° C. for 3 hours, cooled, ground and containing tungstic acid 9.9 g (yield: 79.2% by mass) of [not included in molecular weight calculation]. The titanium dioxide composite (4-2) containing tungstic acid was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

4.2 Antibacterial test of titanium dioxide composite impregnated with tungstic acid (4-2) In the same manner as in Example 1, using test water containing titanium dioxide composite impregnated with tungstic acid, the fluorescent lamp was irradiated for 24 hours. Antibacterial tests were conducted on Escherichia coli and live bacteria. As a result, as shown in Table 2, the number of bacterial colonies after culturing for 48 hours was 0 / mL in both cases of Escherichia coli and general living bacteria.

5.1 Preparation of Titanium Dioxide Composite Impregnated with Ammonium Tungstate (5-2) White Titanium Dioxide CSB {(4-1), Specific Surface Area 280 m with anatase type crystal structure provided by Sakai Chemical Industry Co., Ltd. ² / g} put 10g of (125 mmol) in a petri dish of magnetic, then, of ammonium tungstate para pentahydrate (Wako Pure Chemical Industries, _{Ltd., (NH 4) 10 W 12} O 41 · 5H 2 O, MW: 31.32.52) 2.6 g (WO ₃ ) 10 mmol, 8 mol% with respect to titanium dioxide) and about 80 mL of hot water about 200 mL of homogeneous solution were added and mixed well to impregnate ammonium tungstate. Thereafter, it was dried at about 80 ° C. for about 8 hours. It is fired in a muffle furnace at 400 ° C. for 3 hours, cooled, pulverized, and titanium dioxide composite {TiO _2. ((NH ₄ ) ₁₀ W ₁₂ O ₄₁ ) _0.08 } (5-2) [MW: 79.9, tungstic acid 11.8 g (yield: 93.7%) of [Ammonium is not included in the calculation of molecular weight]. This titanium dioxide composite (5-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

5.2 Antibacterial test of titanium dioxide composite (5-2) impregnated with ammonium tungstate Using test water containing titanium dioxide composite (5-2) impregnated with ammonium tungstate as in Example 1. The antibacterial test was carried out on Escherichia coli and general living bacteria when irradiated with a fluorescent lamp for 24 hours. As shown in Table 2, the number of bacterial colonies after culturing for 48 hours was 0 / mL for both E. coli and general viable bacteria.

Comparative Example 2: Antibacterial test of commercially available titanium dioxide photocatalyst The same anatase type titanium dioxide CSB (4-1) (specific surface area 280 m ² / g) manufactured by Sakai Chemical Industry Co., Ltd. was used as in Example 4. Thus, the number of E. coli and the number of general viable bacteria were measured in the same manner as in Comparative Example 1. As shown in Table 2, the number of colonies of E. coli was 5 / mL and the number of colonies of general viable bacteria was 775 / mL, as shown in Table 2.

Comparison between Examples 4 and 5 and Comparative Example 2 As can be seen from the results in Table 2, the antibacterial property of the present invention using a titanium dioxide composite impregnated with tungstic acid or ammonium tungstate as in Examples 4 and 5 When the agent was added, irradiation with 500 lux for 24 hours using daylight white fluorescent lamps resulted in zero colonies in both cases of E. coli and general viable bacteria other than E. coli. However, it was confirmed that the bacteria were completely killed in both cases of Escherichia coli and live bacteria. On the other hand, when untreated titanium dioxide CSB, which is a commercially available photocatalyst, was used, both E. coli and general living bacteria were alive after 48 hours of culture, although it decreased from before the fluorescent light irradiation. From this comparison, it can be seen that the antibacterial property-imparting agent of the present invention has a remarkable antibacterial action.

6.1 Preparation of Titanium Dioxide Composite (6-2) by Impregnation with Ammonium Sulfate White Titanium Dioxide JA-1 {(6-1) having an anatase type crystal structure provided by Teika Co., Ltd., specific surface area 9 m ² / g } In a magnetic petri dish, and then added 1.32 g of ammonium sulfate (10 mmol, 8 mol% with respect to titanium dioxide) and 10 mL of water made by Wako Pure Chemical Industries, After thoroughly mixing and impregnating with ammonium sulfate, it was dried at about 80 ° C. for 1 hour. Next, after calcining in a muffle furnace at 500 ° C. for 3 hours and cooling, 10.7 g of titanium dioxide composite (6-2) [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] pulverized and containing ammonium sulfate (Yield: 94.5%) was obtained. This titanium dioxide composite (6-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

6.2 Antibacterial test of titanium dioxide composite impregnated with ammonium sulfate (6-2) In the same manner as in Example 1, using a test water containing a titanium dioxide composite impregnated with ammonium sulfate, a white fluorescent lamp was illuminated at 500 lux. Antibacterial tests were performed on E. coli and general living bacteria when irradiated for 24 hours. As a result, as shown in Table 3, the number of bacterial colonies after culturing for 48 hours was 0 / mL for E. coli and 9 / mL for general viable bacteria.

Comparative Example 3: Antibacterial Test of Commercially Available Titanium Dioxide Photocatalyst White Titanium Dioxide JA-1 {(6-1) having anatase type crystal structure provided by Takeka Co., Ltd., the same as that used in Example 6 , Specific surface area 9 m ² / g} was used to measure the number of Escherichia coli and the number of general viable bacteria in the same manner as in Comparative Example 1 when the daylight fluorescent lamp was irradiated for 24 hours at an illuminance of 500 lux. As shown in Table 3, the number of colonies of E. coli was 22 / mL, and the number of general viable colonies was 3000 / mL or more (dense and could not be measured).

7.1 Antibacterial test of titanium dioxide composite impregnated with ammonium sulfate (6-2) at an illuminance of 1000 lux Using the titanium dioxide composite impregnated with ammonium sulfate (6-2) prepared in Example 6, daylight white fluorescent lamp The antibacterial property test was conducted in the same manner as in Example 6 except that the illuminance was increased from 500 lux to 1000 lux. As a result, as shown in Table 3, the number of bacterial colonies after culturing for 48 hours in both cases of Escherichia coli and general viable bacteria was 0 / mL.

Comparative Example 4: Antibacterial Test of Commercial Titanium Dioxide Photocatalyst at 1000 Lux Illuminance White Titanium Dioxide JA-1 having anatase type crystal structure provided by the same Teika Co., Ltd. used in Example 6 { (6-1) Using a specific surface area of 9 m ² / g}, the number of E. coli and the number of viable bacteria were measured in the same manner as in Comparative Example 3 except that the illuminance of the daylight fluorescent lamp was increased from 500 to 1000 lux. did. As shown in Table 3, the number of colonies of E. coli was 3 / mL, and the number of colonies of general viable bacteria was 393 / mL, as shown in Table 3.

Comparison between Examples 6 and 7 and Comparative Examples 3 and 4 In Example 6, irradiation with 500 lux for 24 hours using a white white fluorescent lamp resulted in 0 E. coli / mL. Only a few bacteria remained. However, in the 1000 lux irradiation test of daylight fluorescent lamps, both E. coli and general live bacteria were completely zero. On the other hand, when a commercially available photocatalyst was used, both E. coli and general viable bacteria were alive, although both 500 lux and 1000 lux of daylight fluorescent lamps were reduced from before irradiation. From this comparison, it can be seen that the antibacterial property-imparting agent of the present invention has an excellent antibacterial action.

Comparison of Example 6 and Comparative Example 1 As shown in Table 3, in Example 6, using titanium dioxide having a specific surface area of 9 m ² / g, a general raw material after irradiation for 24 hours at 500 lux of a day white fluorescent lamp was used. The number of bacteria is 9, while in Comparative Example 1, the number of general viable bacteria after irradiation with a daylight fluorescent lamp under the same conditions using a titanium dioxide photocatalyst having a specific surface area of 260 m ² / g is shown in Table 1. As shown, it was 667.
By the way, the result of culturing and examining the number of general viable bacteria before irradiation of the stock solution collected in Teganuma was 4460 as described in Section 1.3 of Example 1. In Example 6, the number of general viable bacteria after irradiation with the daylight fluorescent lamp is 9, and the number is reduced to 0.2% (9/4460 = 0.002). On the other hand, in Comparative Example 1, it was 667, which was reduced to 15% (667/4460 = 0.15). Therefore, Example 6 (complex of titanium dioxide JA-1 and ammonium sulfate) is 75 times (0.150 / 0.0020 = 75) higher in calculation than Comparative Example 1 (titanium dioxide AMT-100 alone). Has antibacterial properties. Furthermore, it is estimated that the photocatalytic action is manifested on the surface (specific surface area), and when the ratio of the specific surface area is taken into consideration, the titanium dioxide composite of Example 6 is only in the case of titanium dioxide AMT-100 of Comparative Example 1. In comparison, it can be seen that it has approximately 2000 times (75 × 260/9 = 2167) high antibacterial properties and has a very high antibacterial property.

8.1 Preparation of Titanium Dioxide Composite (8-2) by Impregnation with Ammonium Sulfate White titanium dioxide JR {(8-1), specific surface area 6 m ² / g} having a rutile-type crystal structure provided by Teika Co., Ltd. Put 10.0 g (125 mmol) in a magnetic petri dish, then add 1.32 g ammonium sulfate (10 mmol, 8 mol% with respect to titanium dioxide) and 10 mL of water made by Wako Pure Chemical Industries, and mix well. After impregnating with ammonium sulfate, it was dried at about 80 ° C. for 1 hour. 10.3 g (yield) of titanium dioxide composite (8-2) [MW: 79.9, ammonium sulfate not included in molecular weight calculation] containing ammonium sulfate after firing in a muffle furnace at 500 ° C. for 3 hours, cooling, pulverizing : 91.0%). This titanium dioxide composite (8-2) was confirmed to have a rutile-type crystal structure from the measurement results of an X-ray diffractometer (XRD).

8.2 Antibacterial test of titanium dioxide composite impregnated with ammonium sulfate (8-2) In the same manner as in Example 1, using a test water containing a titanium dioxide composite impregnated with ammonium sulfate, a daylight white fluorescent lamp was illuminated with an illuminance of 500 lux. The antibacterial test was conducted on Escherichia coli and general live bacteria when irradiated for 24 hours. As a result, as shown in Table 4, the number of bacterial colonies after culturing for 48 hours was 0 / mL for Escherichia coli and 11 / mL for general viable bacteria.

Comparative Example 5: Antibacterial Test of Commercially Available Titanium Dioxide Photocatalyst White Titanium Dioxide JR {(8-1), with a rutile-type crystal structure provided by Teika Co., Ltd., the same as that used in Example 8 Using the surface area of 6 m ² / g}, the number of Escherichia coli and the number of viable bacteria were measured in the same manner as in Comparative Example 1 when a white white fluorescent lamp was irradiated at an illuminance of 500 lux for 24 hours. As shown in Table 4, the number of colonies of E. coli was 46 / mL, and the number of general viable colonies was 3000 / mL or more (dense and could not be measured).

9.1 Antibacterial test of titanium dioxide composite (9-2) impregnated with ammonium sulfate at 1000 lux illuminance Using the titanium dioxide composite (8-2) impregnated with ammonium sulfate prepared in Example 8, day white fluorescent lamp The antibacterial property test was conducted in the same manner as in Example 8 except that the illuminance was increased from 500 lux to 1000 lux. As a result, as shown in Table 4, the number of bacterial colonies after culturing for 48 hours in both cases of E. coli and general viable bacteria was 0 / mL.

Comparative Example 6: Antibacterial Test of Commercially Available Titanium Dioxide Photocatalyst at 1000 Lux Illuminance White Titanium Dioxide JR having the anatase-type crystal structure provided by the same Teika Co., Ltd. used in Example 8 {(8 -1) and the specific surface area of 6 m ² / g}, the number of E. coli and the number of viable bacteria were measured in the same manner as in Comparative Example 5 except that the illuminance of the daylight fluorescent lamp was increased from 500 to 1000 lux. As shown in Table 4, the number of colonies of E. coli was 5 / mL, and the number of colonies of general viable bacteria was 515 / mL, as shown in Table 4.

10.1 Preparation of titanium dioxide composite impregnated with titanium tungstate (10-2) Titanium hydroxide (IV) (meta), β-type [TiO (OH) ₂ ] (MW: 97.9) manufactured by Kishida Chemical Co., Ltd. 12.2 g (125 mmol) and 50% solution of ammonium metatungstate manufactured by Nippon Shin Metal Co., Ltd. [(NH ₄ ) ₆ (H ₂ W ₁₂ O ₄₀ )] (MW: 2656.58) 4.4 g (as WO ₃ ) 10 g of warm water was added to 10 mmol (about 8 mol% with respect to titanium hydroxide) and mixed well, and then dried with a hot air dryer at about 80 ° C. for 3 hours. Titanium dioxide composite {TiO ₂ (Ti (WO ₄ ) ₂ ) _0.08 } (10-2) [MW: 79.9, tungsten, which is fired in a muffle furnace at 500 ° C. for 3 hours, cooled, pulverized and containing titanium tungstate 10.2 g (yield: 70.8%) of titanium oxide is not included in the calculation of molecular weight. This titanium dioxide composite (10-2) was confirmed to have an anatase type crystal structure from the measurement result of an X-ray diffractometer (XRD).

10.2 Antibacterial activity test of titanium dioxide composite impregnated with titanium tungstate (10-2) In the same manner as in Example 1, using test water containing titanium dioxide composite impregnated with titanium tungstate, day white fluorescent lamp Was subjected to antibacterial tests on Escherichia coli and general live bacteria when irradiated with illuminance of 500 lux for 24 hours. As a result, as shown in Table 5, the number of bacterial colonies after 48 hours of culture was 1 / mL for E. coli and 12 / mL for general viable bacteria.

Comparative Example 7: Antibacterial test of commercially available titanium dioxide photocatalyst Titanium hydroxide (IV) (meta), β-type [TiO (OH) ₂ ] (MW) manufactured by Kishida Chemical Co., Ltd., the same as that used in Example 10 : 97.9) 12.2 g (125 mmol) was calcined in a muffle furnace at 500 ° C. for 3 hours, cooled and then ground to obtain 9.6 g of titanium dioxide [MW: 79.9] (yield: 78.8%). Obtained. This titanium dioxide was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD). Using this titanium dioxide, the number of E. coli and the number of viable bacteria were measured in the same manner as in Example 1. As shown in Table 5, the results were 9 Escherichia coli / mL and 905 general live bacteria / mL.

11.1 Antibacterial property test of titanium dioxide composite impregnated with titanium tungstate (10-2) at 1000 lux illuminance Titanium dioxide composite impregnated with titanium tungstate prepared in Example 10 {TiO ₂ · (Ti (WO _{4 2} ) Using _0.08 } (10-2), the number of E. coli and the number of viable bacteria were measured in the same manner as in Example 10 except that the illuminance of the daylight fluorescent lamp was increased from 500 lux to 1000 lux. The results were 0 / ml for both E. coli and general viable bacteria, as shown in Table 5.

Comparative Example 8: Antibacterial test of commercially available titanium dioxide photocatalyst at illuminance of 1000 lux Similar to Comparative Example 7, except that the illuminance of the daylight fluorescent lamp was increased from 500 lux to 1000 lux for the titanium dioxide prepared in Comparative Example 7. The antibacterial test was conducted by the method described above, and the number of E. coli and the number of general viable bacteria were measured. As shown in Table 5, the results were 3 E. coli / mL and 73 E. coli / viable bacteria.

12.1 Preparation of Titanium Dioxide Composite Impregnated with Ammonium Sulfate A titanium dioxide composite impregnated with ammonium sulfate (12-2) was prepared by the same method as in Example 2 using Titanium Dioxide AMT-100 provided by Takeka Co., Ltd. did. This titanium dioxide composite (12-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

12.2 Antibacterial test of titanium dioxide complex impregnated with ammonium sulfate The fresh water collected from Teganuma, Chiba Prefecture (raw water) was used as test water containing bacteria used for the antibacterial test. First, when the number of bacteria in raw water was measured by the same method as described in Example 1, the number of colonies of E. coli was 82 / mL and the number of colonies of general viable bacteria was 5510 / mL.

12.3 Measurement of the number of bacteria when irradiated with a fluorescent lamp To 1 g of the above raw water, prepare a suspension of the titanium dioxide complex (12-2) impregnated with ammonium sulfate obtained in 12.1 at a rate of 10 mg. This was used as test water. The petri dish containing the test water was irradiated to a 500 lux fluorescent lamp in the same manner as in Example 1, and samples were taken at 2, 4, 6, 8, and 24 hours after the start of irradiation, The number of bacteria in each sample was measured by the same method as in Example 1, the time-dependent change in the growth state of the bacteria with the irradiation time of the fluorescent lamp was observed, and the number of colonies in each sample was measured for E. coli and general bacteria. The results are shown in Table 6.

Comparative Example 9: Time-dependent change in antibacterial properties of commercially available titanium dioxide composite Titanium dioxide AMT-100 provided by the same Teika Co., Ltd. as in Example 12 was suspended in raw water as it was and used as suspended water. As in Example 12, the sample was irradiated on a 500 lux fluorescent lamp, samples were taken at 2, 4, 6, 8, and 24 hours after the start of irradiation, and the number of bacteria in each sample was the same as in Example 1. Measured by method. The results are shown in Table 6.

Comparison of Example 12 and Comparative Example 9 As is apparent from Table 6, in Example 12 of the present invention using a titanium dioxide complex, E. coli was already zero in 2 hours after the start of fluorescent lamp irradiation. In general, the number of viable bacteria was 5510 cells / mL, but rapidly decreased to 13 cells / mL, and there was almost no existence after 6 hours of irradiation. On the other hand, in the case of Comparative Example 9 using mere commercially available titanium dioxide, neither Escherichia coli nor general living bacteria are sufficiently reduced even when irradiated with a fluorescent lamp for a long time, and sufficient antibacterial properties are not exhibited. This antibacterial property is insufficient, and after 24 hours, the number of bacteria is increasing again.

13.1. Antibacterial Test of Titanium Dioxide Composite Impregnated with Ammonium Sulfate In this example, the titanium dioxide composite impregnated with ammonium sulfate obtained in Example 2 {TiO ₂ · ((NH ₄ ) ₂ SO ₄ ) _0.08 } (2 -2) was used to conduct an antibacterial test.

13.2. Preparation of Bacterial Solution Escherichia coli IFO 3972 (E. coli) was used as a test strain. A test strain obtained by pre-culturing this Escherichia coli on a normal agar medium (NA medium) manufactured by Eiken Chemical Co., Ltd. at 35 ° C. for 18 to 24 hours is uniformly dispersed in a 1/500 NB medium, and the number of bacteria per mL is about 10 ⁷ to prepare a bacterial solution. In addition, 1 / 500NB culture medium made by Eiken Chemical Co., Ltd., ordinary broth was diluted 500 times with purified water, and the pH was adjusted to 7.0 ± 0.2.

13.3. Preparation of Titanium Dioxide Complex (2-2) and Test Tube Containing Medium Prepared Titanium Dioxide Complex (2-2) impregnated with ammonium sulfate using 1 / 500NB medium so that its concentration becomes 1% The resulting suspension was used. A suspension obtained by adding 0.1 mL of the above bacterial solution to 10 mL of this suspension was poured into a sterilized test tube as a test solution (13-3).

13.4. Irradiation with daylight white fluorescent lamp and measurement of the number of bacteria A test tube containing the test solution (13-3) was washed with a daylight white fluorescent lamp with an illuminance of 500 to 1000 lux at room temperature (FL20SS · W / It was stored under shaking under irradiation of 18.20 type 18W, 1). After 24 hours of storage, the number of viable bacteria in the test solution was measured by a pour plate culture method (35 ° C., 2 days) using a medium in which SCDLP agar medium manufactured by Nippon Pharmaceutical Co., Ltd. was dissolved in sterilized water. The measurement results were as shown in Table 7.
In addition, irradiation with a fluorescent lamp and measurement of the number of viable bacteria were performed by the following methods. That is, about half of the central part of the daylight fluorescent lamp was covered with aluminum foil and shielded, and the light emitting part was set to about 1/2, and placed at the top of the test tube containing the test solution. That is, the shielding amount of the light emitting part of the daylight fluorescent lamp was adjusted so that the illuminance of the test liquid portion in the test tube was 500 to 1000 lux. For the measurement of the number of viable bacteria, if the number of bacteria is expected to be very large like the test solution before irradiation, prepare multiple diluted test solutions that are diluted every 10 times. These were cultured, and those showing 30-300 colonies were counted and multiplied by the dilution factor to obtain the number of E. coli.

As a control, the same test was performed using a 1/500 NB medium to which the titanium dioxide complex (2-2) was not added, and the viable cell count immediately after the addition of the bacterial solution was measured. The measurement result was as described in the column before irradiation in Table 6, and the number of colonies of E. coli was 6.6 × 10 ⁶ cells / mL.

14.1. Antibacterial test of titanium dioxide composite impregnated with titanium sulfate In this example, the titanium dioxide composite {TiO ₂ (Ti (SO ₄ ) ₂ ) _0.08 } impregnated with titanium sulfate obtained in Example 3 was used. An antibacterial test was conducted using (3-2).
14.2. Preparation of Bacterial Solution The bacterial solution prepared in Example 13 was used.

14.3. Preparation of Titanium Dioxide Complex (3-2) and Test Tube Containing Medium Using Titanium Dioxide Complex (3-2) impregnated with Titanium Sulfate using 1 / 500NB medium so that its concentration becomes 1% The prepared suspension was used. A solution obtained by adding 0.1 mL of the above bacterial solution to 10 mL of this suspension was poured into a sterilized test tube as a test solution (14-3).

14.4. Irradiation with daylight white fluorescent lamp and measurement of the number of bacteria A test tube containing the test solution (14-3) was charged with a daylight white fluorescent lamp with an illuminance of 500 to 1000 lux at room temperature (FL20SS · W / 18.20 type 18W, 1) This was stored under shaking. After 24 hours of storage, the number of viable bacteria in the test solution was measured by a pour plate culture method (35 ° C., 2 days) using a medium in which SCDLP agar medium manufactured by Nippon Pharmaceutical Co., Ltd. was dissolved in sterilized water.
The measurement results were as shown in Table 7.

Comparative Example 10: Antibacterial test of commercially available titanium dioxide photocatalyst
10.1. Preparation of Bacterial Solution The bacterial solution prepared in Example 13 was used.
10.2. Preparation of test tube containing commercially available titanium dioxide photocatalyst and medium As a commercially available titanium dioxide photocatalyst, AMT-100 (1-1) manufactured by Example 1 (specific surface area 260 m ² / g) used in Example 1 was used. It was. This AMT-100 titanium dioxide was prepared using 1 / 500NB medium so that the concentration might be 1%. Using this suspension, a suspension obtained by adding 0.1 mL of the above bacterial solution to 10 mL of the suspension was used as a test solution (10-3) and injected into a sterilized test tube.

10.3. Irradiation with daylight white fluorescent lamp and measurement of the number of bacteria A test tube containing the test solution (10-3) was charged with a daylight white fluorescent lamp with an illuminance of 500 to 1000 lux at room temperature (FL20SS · W / 18.20 type 18W, 1) This was stored under shaking. After 24 hours of storage, the number of viable bacteria in the test solution was measured by pour plate culture (35 ° C., 2 days) using a medium in which SCDLP agar medium manufactured by Nippon Pharmaceutical Co., Ltd. was dissolved in sterilized water. The measurement results were as shown in Table 7.

Comparison between Examples 13 and 14 and Comparative Example 10 As described in Table 7, in the case of Examples 13 and 14 using a titanium dioxide complex in the present invention, as many as 6.6 × 10 ⁶ cells / mL were originally prepared. However, the number of bacteria was so reduced that no bacteria were detected by the irradiation of a fluorescent lamp with a daylight white fluorescent lamp of 500 to 1000 lux for about 24 hours. On the other hand, when the commercially available photocatalyst of Comparative Example 10 was used, no significant decrease in the number of bacteria was observed compared to the number of bacteria before irradiation (6.6 × 10 ⁶ cells / mL). Compared with the cases of No. 14 and No. 14, a large difference was observed in antibacterial properties. From this result, it can be seen that even when the number of bacteria is very large, the antibacterial property imparting agent of the present invention has a surprising effect.

  The antibacterial property-imparting agent using the titanium dioxide composite of the present invention is light of fluorescent lamps that can be used for general illumination even without irradiation of light rich in ultraviolet rays such as sunlight, mercury lamps and ultraviolet lamps. It is fully activated with high antibacterial activity. Therefore, it is useful as an antibacterial agent such as antiseptic and antifungal agent in various fields such as food, environment, health and medical care, such as sterilization, antiseptic and antifungal of foods and various other things.

It is a figure which shows the spectral energy distribution of the daylight fluorescent lamp used for the Example.

Claims (7)

  An antibacterial property-imparting agent comprising a titanium dioxide complex formed from titanium dioxide and an acidic substance and / or a salt thereof.   The antibacterial property imparting agent according to claim 1, wherein the titanium dioxide composite exhibits high antibacterial properties by irradiation with a daylight white fluorescent lamp having an illuminance of 2000 lux or less and poor in ultraviolet light.   A titanium dioxide composite obtained by impregnating, adsorbing, or mixing titanium dioxide with an acidic substance and / or salt thereof, or coprecipitation of an aqueous solution of a titanium compound and an aqueous solution of an acidic substance and / or salt thereof The antibacterial property imparting agent according to claim 1 or 2, wherein The acidic substance is represented by the following general formula (I)
H ₂ XO ₄ (I)
[Wherein, X represents a sulfur atom or a tungsten atom. ]
The antibacterial property imparting agent according to any one of claims 1 to 3, wherein the antibacterial property imparting agent is represented by the following formula.   The antibacterial property imparting agent according to any one of claims 1 to 4, wherein the titanium dioxide has an anatase type or rutile type crystal structure, or a mixed crystal structure of anatase type and rutile type.   6. The antibacterial property-imparting agent according to claim 1, wherein the acidic substance is one or more substances selected from the group consisting of sulfuric acid, tungstic acid, and anhydrides thereof. . The salt of an acidic substance is one or more kinds of substances selected from the group consisting of ammonium sulfate, titanium sulfate, ammonium tungstate, and titanium tungstate, according to any one of claims 1 to 6. Antibacterial agent.

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