JP4248976B2 - Cleaning composition. - Google Patents

Description

  The present invention is a cleaning composition suitably used for removing various types of stains, and is safe, simple and effective even under a weak light source, and is particularly useful as a bleaching cleaning agent, a cleaning agent for water, and a mold removing agent. The present invention relates to an agent composition and a cleaning method using the same.

  Conventionally, as a cleaning agent for bleaching and mold removal, a cleaning agent having an oxidizing ability, particularly a cleaning agent containing, as an active ingredient, hypochlorite, particularly sodium hypochlorite, has been used most often. It has been recognized by general users that such a mold removing detergent using hypochlorite can effectively remove mold. However, in order to ensure the stability of hypochlorite, which is an active ingredient, in the product, the pH of the product is high and there is a unique odor. Encourage the implementation of ventilation.

In addition, there are bleach detergents using peroxides typified by hydrogen peroxide, but generally the ability to bleach mold and the like is lower than that of hypochlorite. In the case of hydrogen peroxide, when the pH is increased to 10 or more, the ability to bleach molds and the like is greatly improved by the generation of OOH ⁻ which is an active oxygen species. It is the actual situation that is made neutral or less or dissolved in water or the like at the time of use.

  On the other hand, environmental purification methods using photocatalysts typified by titanium oxide have attracted particular attention in recent years. This is because when a photocatalyst such as titanium oxide is irradiated with light, electrons are excited from the valence band to the conduction band, and holes are generated in the valence band and electrons are generated in the conduction band. The generated holes and electrons react with water and oxygen to produce hydroxyl radicals and superoxide, which have extremely high oxidation ability, which are oxidatively decomposed and purified by pollutants. This is a field that is actively researched because it is a clean method using For example, Patent Document 1 proposes a cleaning agent containing a photocatalyst. However, photocatalytic materials typified by titanium oxide generally absorb only light having a wavelength shorter than the wavelength based on the band gap of the material, and in order to effectively generate active species having strong oxidizing power such as hydroxy radicals, Such a powerful light source was necessary.

Further, Patent Document 2 and Patent Document 3 propose a combined use of a Fenton reaction and a photocatalyst as a treatment method for effectively performing oxidative decomposition of a contaminant with a photocatalyst. However, in the case of the Fenton reaction using FeCl ₃ which lacks stability as a ferric salt, it is necessary to adjust the solution pH to a strongly acidic region. Patent Document 4 also describes that pollutants and ferric salts such as [Fe (CN) ₆ ] ³⁻ are used in the decomposition treatment, but high concentration hydrogen peroxide is used. Since it is characterized by treating contaminants using the temperature rise caused by the thermal reaction, it cannot be prepared in advance as a cleaning composition, and there is a problem with safety, and a light source is also used. Since ultraviolet rays are used, it is unsuitable as a cleaning composition that can be used in general households.
JP 2002-12891 A Japanese Patent Laid-Open No. 11-19664 JP 9-255591 A JP-A-7-265460

  The problem of the present invention is that there is no specific odor, it is safe and easy to handle, and it has a cleaning effect equivalent to or better than that of the prior art even under a weak light source such as a fluorescent lamp, which is a general illumination, particularly bleaching cleaning. An object of the present invention is to provide a stable and effective cleaning composition as a cleaning agent, a cleaning agent for water and a cleaning agent for mold removal.

  The present invention includes (a) a photocatalyst, (b) a compound that can exist stably in a neutral region containing a metal ion whose reduction potential is noble from the conduction charge position of the photocatalyst, and (c) accepts electrons in an aqueous solution. And a cleaning composition containing at least one peroxide selected from the group consisting of peroxides that generate radicals and peroxides that generate hydrogen peroxide, and cleaning by irradiation with visible light Provided is a cleaning method using this cleaning composition that exerts its action.

  The cleaning composition of the present invention can be used in the same manner as a normal bleaching cleaning agent, a water-cleaning cleaning agent, or a mildew-removing cleaning agent, and is excellent in the presence of light, particularly only weak visible light. Demonstrates bleaching and mold removal effect of substances.

[(A) component]
As the photocatalyst of the component (a) of the present invention, a substance having a band gap energy of 2.2 to 3.5 eV, that is, irradiation with ultraviolet light and a visible light source generates electrons and generates holes, which are dissolved in water. react with oxygen or water, but function of decomposing contaminants mold and plumbing to the organic matter as the main is not particularly limited as long as it expresses, preferably contains titanium oxide, e.g., TiO ₂ (anatase Type), TiO ₂ (rutile type), TiO ₂ (brookite type), SrTiO ₃ , CaTiO ₃ , ZnTiO ₃ , Zn ₂ TiO ₄ , Fe ₂ TiO ₅ , CeO—TiO ₂ composite oxide, etc. (hereinafter referred to as titanium oxide, etc.) TiO ₂ is preferable, and TiO ₂ is preferable in terms of safety and low cost. Further, these titanium oxides and the like are doped with metal ions such as Cr, V, Fe, Sn, etc., doped with anions such as N (nitrogen) and S (sulfur), and oxygen defects are introduced. It is more preferable if the wavelength which light absorbs is shifted to a long wavelength. For example, a material in which Cr, V, Fe and the like disclosed in JP-A-9-262482 are contained from the TiO ₂ surface is exemplified.

  Furthermore, the photocatalyst used in the present invention further preferably contains at least one noble metal or noble metal compound (hereinafter referred to as noble metal) selected from Pt, Au, Pd, Ag, Rh, Ru, etc. A photocatalyst in which these noble metals are supported on titanium oxide or the like is more preferable because the effect is further improved. The use amount of these noble metals (supported amount when supported) is preferably 0.01 to 10% by weight, more preferably 0.1 to 3% by weight, based on titanium oxide as a support.

The primary particle diameter of the photocatalyst used in the present invention is not particularly limited, but is preferably 1 nm to 10 μm, and more preferably 1 to 200 nm. Further, the specific surface area of these photocatalyst is not particularly limited, but is preferably ^{0.1~500m 2 / g, 50~300m 2 /} g are preferred for the dispersion property as a detergent composition also becomes excellent .

[Component (b)]
The component (b) of the present invention is a compound that can stably exist in a neutral region containing a metal ion whose reduction potential is nobler than the conduction charge position of the photocatalyst, but “the reduction potential is nobler than the conduction charge position of the photocatalyst. “Is” means that the reduction potential is on the positive side (+ side) from the conduction charge position of the photocatalyst, and “a compound that can exist stably in the neutral region” means water at 25 ° C. and pH 7. Means a compound having a solubility in 1 mmol / L or more.

  The component (b) is preferably a metal ion complex, more preferably an Fe (III) complex, a Mn (III) complex, a Co (III) complex, a Ni (II) complex, a Cu (II) complex, or the like, and Fe (III ) Complexes are particularly preferred. Specifically, for example, ethylenediaminetetraacetic acid iron (III) complex (hereinafter referred to as Fe (III) -EDTA), 2,2′-bipyridineiron (III) complex, oxalate iron (III), pentacyanonitrosyl iron ( III) complexes, thiocyanato iron (III) complexes, and phenanthroline iron (III) complexes. Fe (III) -EDTA is particularly preferable. Since these compounds have a reduction potential nobler than the conduction charge position of the photocatalyst, they are easily reduced by electrons excited in the conduction band of the photocatalyst by light irradiation to become a compound containing a low-oxidation state metal ion. A compound containing a metal ion in an oxidized state reacts with the component (c) to efficiently generate an oxidation active species.

[Component (c)]
Component (c) used in the present invention is at least one selected from a peroxide that accepts electrons in an aqueous solution to generate radicals and a peroxide that generates hydrogen peroxide, and accepts electrons. Peroxides that generate radicals are preferred.

  Examples of peroxides that accept electrons and generate radicals include hydrogen peroxide, and persulfates that generate sulfate ion radicals such as sodium persulfate, potassium persulfate, ammonium persulfate, and mixtures thereof. Persulfate is preferable because it has a reduction potential lower than that of hydrogen peroxide and more easily accepts electrons. Examples of peroxides that generate hydrogen peroxide include sodium percarbonate, sodium perborate, sodium tartrate hydrogen peroxide adduct, sodium tripolyphosphate hydrogen peroxide adduct, sodium pyrophosphate hydrogen peroxide adduct, urea peroxide. Examples thereof include hydrogen oxide adducts, sodium peroxide, calcium peroxide, and the like. In consideration of safety during use, sodium percarbonate and sodium perborate are preferable.

  These components (c) may be used alone or in combination of two or more. Moreover, you may use together the peroxide which generate | occur | produces a radical, and the peroxide which generate | occur | produces hydrogen peroxide.

[Cleaning composition]
The content of the component (a) in the composition of the present invention is preferably 0.001 to 10% by weight, more preferably 0.01% by weight or more from the viewpoint of effectiveness against contaminants, dispersion stability and light. From the viewpoint of suppressing a decrease in the photocatalytic activity due to scattering of light, it is more preferably 1% by weight or less.

  The content of the component (b) in the composition of the present invention is preferably 0.003 ppm to 1% by weight, more preferably 0.03 ppm or more from the viewpoint of effectiveness against pollutants, and 0 from the viewpoint of dispersion stability. More preferred is 0.01% by weight or less.

  The content of the component (c) in the composition of the present invention is preferably 0.003 to 3% by weight, more preferably 0.03% by weight or more in order to show more effective bleaching ability. In consideration of damage to the skin due to adhesion to the body and stability, 0.2% by weight or less is more preferable.

  In the cleaning composition of the present invention, when the component (a) is irradiated with light, the reaction between the generated holes and water, the reaction between the electrons and the component (c), and further reduction by electrons (b) ) And radical (c) produced by the reaction of component (c) with hydroxyl radicals, sulfate radicals, or hydroxyl radicals produced by reaction of sulfate radicals with water, mold and other pollutants mainly organic Decomposes powerfully.

  In the detergent composition of the present invention, when alkalinity becomes strong, hydroxide ions in alkali trap generated hydroxyl radicals and prevent hydroxyl radicals from decomposing contaminants. Since decomposition occurs and stability is deteriorated, it is preferable that the pH is adjusted to less than 10, and that the pH is adjusted to a neutral range of 8 or less, particularly pH 3 to 8 from the viewpoint of safety. preferable.

  The cleaning composition of the present invention contains water and / or a volatile liquid such as ethanol or 2-propanol as a solvent or a dispersion medium. Of these, water is preferred. Furthermore, it is preferable to contain a buffering agent in order to improve stability. Examples of the buffer include boric acid, citric acid, phthalic acid, and salts thereof.

  Moreover, the cleaning composition of the present invention may contain a surfactant to the extent that its function is not impaired. The surfactant improves the wettability to the site where the target contaminant is attached, and acts as a dispersion stabilizer for the photocatalyst.

  Examples of the surfactant used in the present invention include at least one selected from nonionic surfactants, amphoteric surfactants, cationic surfactants, and anionic surfactants.

  Nonionic surfactants include polyoxyethylene alkyl phenyl ether, polyoxypropylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyethylene glycol alkyl ester, polyethylene glycol, glycerin, sorbitol, alkylamine oxide. Among them, those having 6 to 22 carbon atoms in the alkyl moiety are preferable. Examples of amphoteric surfactants include amine oxides such as alkyldimethylamine oxide, betaine surfactants such as alkyldimethylamino fatty acid betaine, alkylcarboxymethylhydroxyethyl imidazolium betaine, etc. Among them, alkyl having 8 to 18 carbon atoms. Alkyldimethylamine oxide having a group is preferred. Examples of the cationic surfactant include primary amine salts, secondary amine salts, tertiary amine salts, and quaternary ammonium salts. Among them, quaternary ammonium salts are preferable. Anionic surfactants include higher alcohol sulfates, carboxylates, α-olefin sulfonates, alkylbenzene sulfonates, sodium alkylsulfosuccinates, sulfate esters of higher alcohol ethylene oxide adducts, alkylphenols and polyethylene glycols. Examples thereof include ether sulfates. Among them, sulfate esters of higher alcohols having 10 to 22 carbon atoms are preferable, but these surfactants can be appropriately blended.

  Moreover, in the cleaning composition of the present invention, a thin film forming component or a thickener may be appropriately blended in order to maintain the effect at the contaminated site and improve the adhesion. Examples of these thin film forming components and thickeners include silicones, modified silicones, and fluorine-containing polymers that are not easily decomposed by a photocatalyst, and specifically include alcohol-modified silicones, amino-modified silicones, vinylidene fluoride, tetrafluoride. Ethylene and the like. These thin film forming components and thickeners can be appropriately blended to such an extent that the effects are not impaired.

  Examples of the method of using the cleaning composition of the present invention include application by spraying from a trigger-equipped container and application by brush. Further, after application, a method of leaving it to dry to form a thin film, a method of washing away with water, or a photocatalyst For example, there is a method of lightly rubbing with a sponge or the like when washing away, which is expected to remove physical contaminants.

  The cleaning composition of the present invention can be used in places where water is used in homes such as kitchens, toilets, bathrooms, toilets and laundry spaces, and tools used therein, such as stainless steel tubs, water supplies, basins, tiles and windows. It is excellent for cleaning glass and the like, and particularly excellent as a detergent composition for removing mold.

  In order for the cleaning composition of the present invention to act effectively, a weak light source is sufficient, and ultraviolet rays are not particularly required. Therefore, the cleaning composition of the present invention can be irradiated with visible light to exert its cleaning action, and it can be used for daylighting, slight irradiation of fluorescent lamps, for example, even in low light intensity such as bathrooms and toilets. Can be demonstrated. Here, the visible light means light containing a wavelength of 400 nm or more.

  In the examples of the present invention, ppm represents parts per million by weight.

Example 1
25 g of a 1200 ppm aqueous hydrogen peroxide solution, 0.01 g of titanium oxide (manufactured by Taki Chemical Co., Ltd., A-100, conduction charge level -0.16 V) as a photocatalyst, and Fe (III) concentration of 12 ppm A detergent composition was obtained by adding 25 g of an aqueous solution of (III) -EDTA (manufactured by Wako Pure Chemicals, reduction potential 0.14 V).

Example 2
A detergent composition was obtained in the same manner as in Example 1 except that 25 g of an Fe (III) -EDTA (manufactured by Wako Pure Chemical Industries) aqueous solution having an Fe (III) concentration of 1.2 ppm was used.

Example 3
A detergent composition was obtained in the same manner as in Example 1 except that 25 g of an aqueous solution of ammonium persulfate (1200 ppm as persulfate ion) was used instead of hydrogen peroxide.

Example 4
A detergent composition was obtained in the same manner as in Example 3 except that 25 g of an Fe (III) -EDTA (manufactured by Wako Pure Chemical Industries) aqueous solution having an Fe (III) concentration of 1.2 ppm was used.

Example 5
A detergent composition was obtained in the same manner as in Example 3 except that 25 g of an Fe (III) -EDTA (manufactured by Wako Pure Chemical Industries) aqueous solution having an Fe (III) concentration of 0.12 ppm was used.

Example 6
A detergent composition was obtained in the same manner as in Example 3 except that 25 g of an Fe (III) -EDTA (manufactured by Wako Pure Chemical Industries) aqueous solution having an Fe (III) concentration of 0.012 ppm was used.

Comparative Example 1
As a photocatalyst, 0.01 g of titanium oxide (manufactured by Taki Chemical Co., Ltd., A-100) was dispersed in 50 g of distilled water to obtain a cleaning composition.

Comparative Example 2
To 50 g of 600 ppm aqueous hydrogen peroxide solution, 0.01 g of titanium oxide (manufactured by Taki Chemical Co., Ltd., A-100) was added as a photocatalyst to obtain a cleaning composition.

Comparative Example 3
A cleaning composition was obtained by adding 0.01 g of titanium oxide (manufactured by Taki Chemical Co., Ltd., A-100) as a photocatalyst to 50 g of an aqueous ammonium persulfate solution having a persulfate ion concentration of 600 ppm.

Test example 1
About the cleaning composition obtained in Examples 1-6 and Comparative Examples 1-3, the decomposition | disassembly performance of organic substance stain was evaluated by the following test method 1 and test method 2. The results are shown in Table 1.

<Test method 1>
Using methylene blue trihydrate (manufactured by Wako Pure Chemical Industries, Ltd., C ₁₆ H ₁₈ N ₃ S · Cl · 3H ₂ O), a 20 ppm methylene blue aqueous solution is obtained. 15 g of the detergent composition is placed in a 30 cc screw tube, and 15 g of 20 ppm methylene blue aqueous solution is added to prepare 30 g of 10 ppm methylene blue test solution.

Using a fluorescent lamp (Toshiba Mellow Look straight tube type 15W), samples are collected 30 minutes and 180 minutes after the test solution is irradiated with light having an illuminance of 3800 lx. The collected sample is filtered through a 0.2 μm filter. The absorbance spectrum of the test solution is measured in a wavelength range of 400 to 700 nm with a spectrophotometer (HITACHI U-4000 type), and the concentration of methylene blue is calculated from the absorbance at the peak top (663 nm). The methylene blue concentrations after 30 minutes, 60 minutes, 120 minutes and 180 minutes are C _{30 min} , C _{60 min} , C _{120 min} and C _{180 min} , respectively.

  The decomposition rate k of methylene blue was determined according to the following formula, and used as an index of the decomposition performance of organic dirt.

Decomposition rate: k = -ln (C _{180 min} / C _{30 min} ) / (180-30)
In the case where the absorbance was not observed after 180 minutes, the decomposition rate was determined using the following equation based on the analysis value after 60 minutes or 120 minutes.

The degradation _{rate: k = -ln (C 60min /} C 30min) / (60-30)
The degradation _{rate: k = -ln (C 120min /} C 30min) / (120-30)
<Test method 2>
Test method 1 using 30 W of 10 ppm methylene blue test solution prepared in Test Method 1 using a 500 W / m ² xenon lamp (SUNSET CPS + manufactured by Heraeus, Germany), which is obtained by removing ultraviolet light of 400 nm or less with sodium nitrite instead of a fluorescent lamp. The decomposition rate k of methylene blue was determined in the same manner as described above.

Claims (5)

  (A) a photocatalyst, (b) a compound that can exist stably in a neutral region containing a metal ion whose reduction potential is noble from the conduction charge position of the photocatalyst, and (c) an electron in an aqueous solution to accept radicals. A cleaning composition comprising a peroxide that is generated and at least one peroxide selected from the group consisting of peroxides that generate hydrogen peroxide. The cleaning composition according to claim 1, wherein the component (a) contains titanium oxide. The detergent composition according to claim 1 or 2, wherein the component (b) is a metal ion complex. The cleaning composition according to any one of claims 1 to 3, wherein the component (c) is a peroxide that accepts electrons in an aqueous solution to generate radicals. The cleaning method using the cleaning composition in any one of Claims 1-4 which irradiates visible light and exhibits a cleaning effect.