Copper-containing layered double hydroxide, its production method, deodorant composition, antibacterial composition, and ultraviolet absorber composition

Abstract

To provide a layered double hydroxide with a novel function in addition to an adsorption function of a volatile sulfur compound.SOLUTION: A copper-containing layered double hydroxide represented by a formula (1) below is provided. The copper-containing layered double hydroxide is obtained by reacting an aqueous solution containing copper with an aqueous solution containing aluminum under conditions where the pH is 8 or higher. Cu1-xAlx(OH)2An-x / n mH2O (1) (in the formula (1), An- is an n-valent anion, x is a number satisfying 0<x<1, n is a number satisfying 1≤n, and m is a number satisfying 0<m).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a copper-containing layered double hydroxide and a method for producing the same, as well as a deodorant composition, an antibacterial composition and an ultraviolet absorber composition. [Background technology]

[0002] In recent years, there has been growing interest in oral hygiene, such as preventing bad breath and keeping the oral cavity clean. There are many commercially available products for preventing bad breath, such as mouthwashes, toothpastes, and chewing gums that contain fragrances or antibacterial ingredients, but the effectiveness of these products in preventing bad breath is only temporary.

[0003] Therefore, layered double hydroxides (LDHs), such as hydrotalcite, have been attracting attention as dental materials that can remove volatile sulfur compounds (VSCs), which cause bad breath. Layered double hydroxides are classified as a type of clay mineral and have the general formula M 2+ 1-x M 3+ x (OH)2A n- x / n It is expressed in mH2O and is known to have a high adsorption effect. For example, Patent Document 1 discloses that M in the above general formula 2+ is zinc (Zn 2+ ) and M 3+ is aluminum (Al 3+ ) and A n- is carbonate ion (CO3 2- ) layered double hydroxides, 2+ Magnesium (Mg 2+ ) and M 3+ is iron (Fe 3+ ) and A n- is carbonate ion or chloride ion (Cl - ) is disclosed as an adsorbent for volatile sulfur compounds. [Prior art documents]

Patent Document

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For such layered double hydroxides having an adsorption function for volatile sulfur compounds, new functions are required. An object of the present invention is to provide a layered double hydroxide having a new function in addition to an adsorption function for volatile sulfur compounds.

Means for Solving the Problems

[0006] The present invention has the following aspects. [1] A copper-containing layered double hydroxide represented by the following general formula (1). Cu 1-x Al x (OH)2A n- x / n ·mH2O ···(1) (In formula (1), A n- is an n-valent anion, x is a number satisfying 0 < x < 1, n is a number satisfying 1 ≤ n, and m is a number satisfying 0 < m. [2] A deodorant composition containing the copper-containing layered double hydroxide of [1] above. [3] An antibacterial agent composition containing the copper-containing layered double hydroxide of [1] above. [4] An ultraviolet absorber composition containing the copper-containing layered double hydroxide of [1] above. [5] A method for producing the copper-containing layered double hydroxide of [1] above, A method for producing a copper-containing layered double hydroxide, which comprises reacting an aqueous solution containing copper and an aqueous solution containing aluminum under conditions where the pH becomes 8 or higher.

Effects of the Invention

[0007] According to the present invention, a layered double hydroxide having a new function in addition to the function of adsorbing volatile sulfur compounds can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an energy dispersive X-ray analysis spectrum of the copper-containing layered double hydroxide obtained in Example 1. [Figure 2] FIG. 1 shows the results of powder X-ray diffraction measurements of the copper-containing layered double hydroxides and copper (II) oxide obtained in Examples 1 to 3. [Figure 3] 1 shows infrared absorption spectra of the copper-containing layered double hydroxides obtained in Examples 2 and 3, measured by Fourier transform infrared spectroscopy. [Figure 4] FIG. 1 is a graph showing the rate of change in the total H2S concentration in a container after the copper-containing layered double hydroxides obtained in Examples 2 and 3 were added. [Figure 5] FIG. 1 shows the change over time in the H2S concentration in the H2S water and headspace in the container after the copper-containing layered double hydroxide obtained in Example 2 was added. [Figure 6] FIG. 1 shows the change over time in the H2S concentration in the H2S water and headspace in the container after the copper-containing layered double hydroxide obtained in Example 3 was added. [Figure 7] 1 shows an ultraviolet-visible absorption spectrum of the copper-containing layered double hydroxide obtained in Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described in detail below. The symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0010] [Copper-containing layered double hydroxide] The copper-containing layered double hydroxide according to the first aspect of the present invention is a compound represented by the following general formula (1). Cu 1-x Al x (OH)2A n-x / n ·mH₂O ···(1) (In formula (1), A n- is an n-valent anion, x is a number satisfying 0 < x < 1, n is a number satisfying 1 ≤ n, and m is a number satisfying 0 < m.)

[0011] In formula (1), A n- is an n-valent anion.) n is a number satisfying 1 ≤ n, preferably 1 to 3, more preferably 1 or 2.) Examples of the n-valent anion include monovalent anions such as chloride ion (Cl - ), fluoride ion (F - ), bromide ion (Br - ), iodide ion (I - ), nitrate ion (NO₃ - ), hydroxide ion (OH - ), acetate ion (CH₃COO - ), carboxylate ion other than acetic acid (R-COO - ), etc.; divalent anions such as carbonate ion (CO₃ 2- ), sulfate ion (SO₄ 2- ), etc.; trivalent anions such as phosphate ion (PO₄ 3- ), borate ion (BO₃ 3- ), etc. Among these, monovalent or divalent anions are preferred, and among them, chloride ion, nitrate ion, and carbonate ion are particularly preferred. Also, from the viewpoint of exhibiting ultraviolet absorption ability, chloride ion and nitrate ion are preferred.)

[0012] x is a number satisfying 0 < x <​​​​​​​​​​n- x / n The copper-containing layered double hydroxide has a layered structure with multiple positively charged host layers and intermediate layers, i.e., guest layers between the host layers, to compensate for the charge.

[0014] The copper-containing layered double hydroxide can be obtained, for example, by reacting an aqueous solution containing copper (S1) with an aqueous solution containing aluminum (S2) under conditions where the pH is 8 or higher. The aqueous solution (S1) can be obtained by dissolving a copper compound such as copper chloride, copper sulfate, or a hydrate thereof in water. As the copper compound, copper chloride is preferred. The copper compounds may be used alone or in combination of two or more. The copper compound may be an anhydrous or hydrated.

[0015] The aqueous solution (S2) can be obtained by dissolving an aluminum compound such as aluminum nitrate, aluminum sulfate, aluminum phosphate, aluminum chloride, or a hydrate thereof in water. As the aluminum compound, copper chloride is preferred. The aluminum compounds may be used alone or in combination of two or more. The aluminum compound may be anhydrous or hydrated.

[0016] The ratio of the aqueous solution (S1) to the aqueous solution (S2) is preferably such that the amount of the aluminum compound is 0.2 to 0.5 mol, more preferably 0.25 to 0.35 mol, per 1 mol of the copper compound. Alternatively, the copper compound and aluminum compound may be dissolved in water in such a manner that the mixing ratio thereof preferably falls within the above-mentioned range to prepare an aqueous solution (S12) containing copper and aluminum, and then this aqueous solution (S12) may be reacted.

[0017] The reaction is preferably carried out in the presence of anions. n-It is preferable to dropwise add the aqueous solution (S1) and the aqueous solution (S2) or dropwise add the aqueous solution (S12) to the aqueous solution (S3) of the salt of the above to carry out the reaction. For example, A n- When producing a copper-containing layered double hydroxide in which is a carbonate ion, the aqueous solution (S3) can also be obtained by dissolving a carbonate such as sodium carbonate, calcium carbonate, potassium carbonate, barium carbonate, magnesium carbonate, lithium carbonate, or ammonium carbonate in water. As the carbonate, sodium carbonate and calcium carbonate are preferred. The carbonates may be used alone or in combination of two or more. The concentration of carbonate in the aqueous solution (S3) is preferably 1 to 5 mol, more preferably 1 to 3 mol, of carbonate per 1 mol of copper compound.

[0018] A n- When producing a copper-containing layered double hydroxide in which is a chloride ion, the aqueous solution (S3) can be obtained by dissolving a metal chloride such as sodium chloride, calcium chloride, potassium chloride, barium chloride, or magnesium chloride in water. Sodium chloride is preferred as the metal chloride. The metal chlorides may be used alone or in combination of two or more. The concentration of the metal chloride in the aqueous solution (S3) is preferably 1 to 5 mol, more preferably 1 to 3 mol, of the metal chloride per 1 mol of the copper compound.

[0019] A n- When producing a copper-containing layered double hydroxide in which nitrate ions are present, the aqueous solution (S3) can be obtained by dissolving a nitrate such as sodium nitrate, calcium nitrate, potassium nitrate, barium nitrate, or magnesium nitrate in water. Sodium nitrate is preferred as the nitrate. The nitrates may be used alone or in combination of two or more. The concentration of the nitrate in the aqueous solution (S3) is preferably 1 to 5 mol, more preferably 1 to 3 mol, of the nitrate per 1 mol of the copper compound.

[0020] In addition, A n- When producing a copper-containing layered double hydroxide in which is an anion other than carbonate ion, it is preferable to aerate the water used to prepare aqueous solution (S1), aqueous solution (S2), aqueous solution (S12), and aqueous solution (S3), or the reaction solution, with an inert gas such as nitrogen gas. This allows the carbonate ions to be removed by aeration even if they are present in the water, and anions other than carbonate ion to be easily introduced into the guest layer.

[0021] The reaction is carried out under conditions such that the pH of the reaction solution at 20°C is 8 or higher. The pH of the reaction solution at 20°C is preferably 8.5 or higher, more preferably 9 or higher, even more preferably 9.5 or higher, and particularly preferably 10 or higher. The pH of the reaction solution at 20°C is preferably 12 or lower. If the pH of the reaction solution is equal to or higher than the above lower limit, the reaction proceeds easily. Here, the reaction solution refers to a mixed solution of aqueous solution (S1) and aqueous solution (S2), a mixed solution of aqueous solution (S1), aqueous solution (S2), and aqueous solution (S3), aqueous solution (S12), or a mixed solution of aqueous solution (S12) and aqueous solution (S3).

[0022] The pH of the reaction solution can be adjusted, for example, by adding a pH adjuster or an aqueous solution thereof to the reaction solution. Examples of pH adjusters include alkali metal salts such as sodium hydroxide and potassium hydroxide; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; inorganic acids such as sulfuric acid, hydrochloric acid and phosphoric acid; and organic acids such as citric acid, paratoluenesulfonic acid and cumenesulfonic acid. The pH adjusters may be used alone or in combination of two or more.

[0023] The temperature of the reaction liquid is preferably 60°C or lower, more preferably lower than 60°C, even more preferably 55°C or lower, even more preferably 50°C or lower, particularly preferably 45°C or lower, and most preferably 40°C or lower. The temperature of the reaction liquid is preferably 20°C or higher, more preferably 25°C or higher, and even more preferably 30°C or higher. If the temperature of the reaction liquid is above the above lower limit, the reaction proceeds easily. If the temperature of the reaction liquid is below the above upper limit, the production of by-products such as copper oxide can be suppressed. Since the lower the temperature of the reaction liquid, the more likely the production of by-products is to be suppressed, particularly when using a copper-containing layered double hydroxide for the purpose of removing bad breath, the temperature of the reaction liquid is preferably below 60°C.

[0024] The reaction time is not particularly limited, but is preferably 1 to 48 hours, more preferably 6 to 24 hours.

[0025] Since the reaction product is obtained as a precipitate, the precipitate is aged if necessary and then filtered, and the filtered product is washed if necessary and then dried to obtain a copper-containing layered double hydroxide.

[0026] The copper-containing layered double hydroxide of the first embodiment of the present invention described above has a guest layer A n- is mainly hydrogen sulfide ion (HS - ), and the H2O in the guest layer is replaced mainly with hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide ((CH3)2S), allowing volatile sulfur compounds to be adsorbed and removed by the guest layer. Copper has a low minimum inhibitory concentration (MIC), which is the minimum concentration required to inhibit bacterial growth. The smaller the MIC, the better the antibacterial properties. The copper-containing layered double hydroxide of the first aspect of the present invention contains copper, which has a low MIC, and therefore is not only able to adsorb and remove volatile sulfur compounds, but also has excellent antibacterial properties and can prevent bacterial growth. The copper-containing layered double hydroxide of the first aspect of the present invention dissolves in an acidic environment that dissolves tooth enamel, for example, when tooth decay occurs, generating copper ions. Specifically, in a pH 5.5 environment, approximately 25% by mass of the total mass of the copper-containing layered double hydroxide dissolves within 24 hours. The generation of copper ions further enhances antibacterial properties and inhibits bacterial growth. Therefore, the use of the copper-containing layered double hydroxide of the first aspect of the present invention can also be expected to be effective in preventing tooth decay.

[0027] Thus, the copper-containing layered double hydroxide of the first aspect of the present invention has an antibacterial property in addition to the function of adsorbing volatile sulfur compounds, i.e., a deodorizing function. In particular, guest group A n- When is a chloride ion or a nitrate ion, it also has ultraviolet absorbing ability.

[0028] The copper-containing layered double hydroxide of the first aspect of the present invention can adsorb and remove volatile sulfur compounds and has excellent antibacterial properties, and therefore can be suitably used as a deodorant, antibacterial agent, or an active ingredient thereof. n- is a chloride ion or a nitrate ion, the copper-containing layered double hydroxide of the first aspect of the present invention can also be suitably used as an ultraviolet absorber or an active ingredient thereof. When the copper-containing layered double hydroxide of the first aspect of the present invention is used as a deodorant, antibacterial agent, ultraviolet absorber, or an active ingredient thereof, it can also be used in combination with an appropriate additive that is usually used.

[0029] For example, when using a copper-containing layered double hydroxide for the purpose of removing bad breath, the copper-containing layered double hydroxide may be blended as an additive in mouthwashes, toothpastes, chewing gum, etc. The copper-containing layered double hydroxide may also be blended as an additive in the resin materials of toothbrushes, tongue brushes, finger cots for toothpaste, toothpaste sheets, etc. Furthermore, the copper-containing layered double hydroxide may also be blended as an additive in the resin or metal materials of dentures and dental implants.

[0030] For example, to remove body odor, the copper-containing layered double hydroxide may be sprayed on the body, or to remove odors from food waste, toilets, drains, etc., the copper-containing layered double hydroxide may be sprayed on these. In addition to the above, unpleasant odors can also be removed by adding the copper-containing layered double hydroxide to sewage, sludge, etc., or by impregnating textile products such as masks, curtains, pillowcases, sheets, underwear, and socks with the copper-containing layered double hydroxide.

[0031] In addition, guest group A n- When is a chloride ion or a nitrate ion, for example, a molded article obtained by adding a copper-containing layered double hydroxide to a resin material can be prevented from discoloring, such as yellowing. The copper-containing layered double hydroxide may also be added to a sunscreen agent.

[0032] [Deodorant composition] The deodorant composition according to the second aspect of the present invention contains the copper-containing layered double hydroxide according to the first aspect of the present invention. The deodorant composition may contain components other than the copper-containing layered double hydroxide of the first aspect of the present invention (hereinafter also referred to as "other components"). The other components are not particularly limited as long as they are known components that are usually used in deodorant compositions.

[0033] [Antibacterial composition] The antibacterial composition according to the third aspect of the present invention contains the copper-containing layered double hydroxide according to the first aspect of the present invention. The antimicrobial composition may contain other ingredients. The other components are not particularly limited as long as they are known components that are usually used in antibacterial compositions.

[0034] [Ultraviolet absorber composition] The ultraviolet absorbent composition according to the fourth aspect of the present invention contains the copper-containing layered double hydroxide according to the first aspect of the present invention. The ultraviolet absorbent composition may contain other components. The other components are not particularly limited as long as they are known components that are usually used in ultraviolet absorbent compositions. [Example]

[0035] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The embodiments of the present invention can be modified in various ways as long as the gist of the present invention is not changed. It should be noted that Examples 1 to 3 are reference examples.

[0036] [Measurement and evaluation method] <Energy dispersive X-ray analysis> The copper-containing layered double hydroxide was measured by energy dispersive X-ray spectroscopy (EDX (or EDS): Energy Dispersive X-ray spectroscopy) under the following measurement conditions. Measurements were performed using a field emission scanning electron microscope (FE-SEM) (manufactured by JEOL Ltd., product name "JSM6500FS"), and elemental analysis was performed using EDS (manufactured by JEOL Ltd., product name "JSM-6460LA") using simplified quantitative analysis (ZAF method) at an accelerating voltage of 25 kV and a vacuum of 5.00 × 10 -4 The measurement was performed under conditions of 0.01 Pa or less, an irradiation current of 10 A, and an irradiation time of 200 s. The measurement sample was fixed to an aluminum plate (10 mm x 10 mm) with conductive tape (Nissin EM Co., Ltd., product name "7321") and dried for 24 hours at room temperature (20 °C) using a vacuum dryer (AS ONE Corporation, product name "KVO-300"). Then, a 12 nm osmium coating was applied using an osmium plasma coater (Filgen Co., Ltd., product name "OPC60A").

[0037] <Powder X-ray diffraction> The copper-containing layered double hydroxide and copper oxide were measured by powder X-ray diffraction (XRD: Power X-ray Diffraction) under the following measurement conditions. The measurement was performed using an X-ray diffractometer (Rigaku Corporation, product name "RINT2200"), a Co target, and a monochromator. The crystalline phase was identified using analysis software (Rigaku Corporation, product name "JADE6"). The measurement sample was finely crushed in an agate mortar and placed on a glass plate (20 x 18 mm) with a 0.5 mm deep indentation. 2 The measurement sample was filled into a sample holder (manufactured by Rigaku Corporation) and attached to an X-ray diffraction apparatus so that the diffraction plane was visible, and measurements were performed. (Measurement conditions) Scan range: 10~60° Sampling width: 0.02° Scan speed: 2.0° / min Applied voltage: 40kV, ·Applied current: 20mA, Divergence slit: 1°, Scattering slit: 0.05mm, Receiving slit: 0.3mm

[0038] <Fourier transform infrared spectroscopy> The copper-containing layered double hydroxide was measured by Fourier transform infrared spectroscopy (FT-IR) under the following measurement conditions. A Fourier transform infrared spectrometer (manufactured by JASCO Corporation, product name "FT / IR-430") was used for the measurement, and spectral analysis was performed using analysis software (manufactured by JASCO Corporation, product name "Spectra Manager"). The measurement sample was prepared using the KBr method. A measurement sample was added to fine powder of KBr (special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) at a ratio of 0.1% by mass, ground in an agate mortar, thoroughly mixed, and then placed in a tablet press and pressed using a hydraulic press (manufactured by JASCO Corporation, product name "MP-1"). (Measurement conditions) Measurement range: 400~4000cm -1 , Accumulation count: 100 times ·Resolution: 4cm -1 .

[0039] <Composition analysis using inductively coupled plasma> (Creating a calibration curve) 40 mL of nitric acid (HNO3, molecular weight 63.01, first grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was slowly added dropwise to 500 mL of ultrapure water (Milli-Q water) to prepare 1 M nitric acid. The Cu standard solution was prepared as follows. 5 mL of copper standard solution (Cu 1000) (1003 mg / L, Fujifilm Wako Pure Chemical Industries, Ltd.) was measured using a 5 mL volumetric pipette (JIS standard, ±0.015 mL, Shibata Chemical Co., Ltd.) and placed in a 50 mL volumetric flask (JIS standard, ±0.06 mL, AS ONE Corporation). 1 M nitric acid was added until the total volume reached 50 mL, creating a 100 ppm Cu standard solution. The 100 ppm Cu standard solution was similarly diluted 10-fold to create a 10 ppm Cu standard solution. 5 mL of the 100 ppm Cu standard solution was measured using a volumetric pipette and placed in a 100 mL volumetric flask (JIS standard, ±0.10 mL, AS ONE Corporation). 1 M nitric acid was added until the total volume reached 100 mL, creating a 5 ppm Cu standard solution. Al standard solutions of 100 ppm, 10 ppm, and 5 ppm were prepared using the same procedure as for the Cu standard solution. These Cu and Al standard solutions and a blank (1 M nitric acid) were quantitatively analyzed using an inductively coupled plasma (ICP) optical emission spectrometer (Hitachi High-Tech Science Corporation, product name "VISTA-MPX"), and calibration curves for Cu and Al were created, respectively.

[0040] (Preparation of measurement samples) 0.002 g of copper-containing layered double hydroxide was added to 10 mL of 1 M nitric acid and stirred until completely dissolved. The solution was quantitatively analyzed using an ICP emission spectrometer, and composition analysis was performed using the calibration curve created earlier.

[0041] <Hydrogen sulfide adsorption test> (Preparation of hydrogen sulfide) A silicone stopper was attached to each of two side tubes of a 500 mL four-neck flask, and a silicone stopper with a glass tube attached was attached to one side tube. Separately, 150 mL of ultrapure water (Milli-Q water) was placed in a 200 mL Erlenmeyer flask, and a glass tube and a bubbling tube were attached through a silicone stopper. A glass tube attached to a four-neck flask was connected to a bubbling tube attached to an Erlenmeyer flask via a silicone tube and a two-way stopcock. A gas washing bottle filled with 1 mol / L sodium hydroxide solution was connected to the glass tube attached to the Erlenmeyer flask via a silicone tube. A calcium chloride tube was attached to the gas washing bottle via a silicone tube. 3 g of iron sulfide (grade 1, Fujifilm Wako Pure Chemical Industries, Ltd.) was weighed out using an analytical balance and placed in a four-neck flask. 15 mL of 1 mol / L dilute sulfuric acid was added through a separatory funnel to generate hydrogen sulfide. The generated hydrogen sulfide was passed through ultrapure water (Milli-Q water) in an Erlenmeyer flask and bubbled for approximately 15 minutes. The 1 mol / L diluted sulfuric acid was prepared by weighing sulfuric acid (special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in a measuring cylinder and diluting it 36 ​​times. These operations were carried out in a draft chamber while wearing rubber gloves, protective glasses, and a gas mask.

[0042] (Adsorption / collection device) A commercially available 200 mL Erlenmeyer flask was fitted with a stirrer and a flat stopper. A side tube with a screw was attached to the Erlenmeyer flask to create a two-neck flask. A hole cap with a septum was attached to the side tube. 1 mL of the hydrogen sulfide water prepared earlier was weighed out using a volumetric pipette and diluted 10 times with ultrapure water (Milli-Q water) to prepare a total volume of 150 mL of hydrogen sulfide water (HS water). Immediately after preparation, the HS water attempts to reach equilibrium between the gas and liquid phases, causing the hydrogen sulfide concentration to change constantly in both the gas and liquid phases. Therefore, to speed up the transition to equilibrium, the solution was stirred at 300 rpm for 60 minutes using a hot stirrer at room temperature (20°C). 0.1 g of copper-containing layered double hydroxide was weighed on an analytical balance and dropped into HS water in a two-neck flask. The HS water was stirred, and 2 μL of HS water was sampled from the HS water solution in the flask immediately after the addition (0 hours), 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, and 24 hours later using a microsyringe (Hamilton, product name "701N Standard PT-2 10 μL"). The concentrations of the sampled gas and HS water were measured using a gas chromatograph equipped with a flame photometric detector. The H2S water was collected using the solvent flash injection method, which involves introducing 1 μL of ultrapure water (Milli-Q water), air, 2 μL of the measurement solution (H2S water), and air into the syringe in this order, thereby avoiding residual sample in the needle and minimizing measurement errors.

[0043] (Creating a calibration curve) A calibration curve was prepared in the following manner. The vessel used was a 5.0 L round separable flask equipped with a four-neck separable cover. A separating funnel was attached to the main tube of the separable cover, hole caps with septa were attached to two side tubes, and a two-way cock was attached to one side tube to allow gas to flow in and out. First, the following process was performed to remove molecules that could affect hydrogen sulfide adsorption. A vacuum gauge (manufactured by Ichinen TASCO, product name "TA142BH") and a two-way stopcock were connected to the container via a silicone tube. A diaphragm pump (manufactured by ULVAC, product name "200 Pa DAU-20") was connected to the two-way stopcock via a silicone tube, and the container was degassed. The diaphragm pump was then reconnected to a high-purity hydrogen sulfide cylinder, and high-purity hydrogen sulfide gas (48.5 ppm) was introduced into the container until atmospheric pressure was reached. Using a gas-tight syringe (manufactured by Ito Seisakusho Co., Ltd., product name "MS-GAN025"), 0.10 mL and 0.15 mL of the generated gas containing hydrogen sulfide were sampled from the separable flask through a hole cap with a septum, and introduced into a gas chromatograph equipped with a flame photometric detector (manufactured by Shimadzu Corporation, product name "FPD-GC, GC-14B"). A calibration curve was created using three points, including the measured values ​​and the 0 mL data.

[0044] <Ultraviolet-visible spectroscopy> The copper-containing layered double hydroxide was measured by ultraviolet-visible absorption spectroscopy (UV-VIS) under the following conditions: The measurement was performed using an ultraviolet-visible-near-infrared (UV-Vis-NIR) spectrophotometer (Shimadzu Corporation, product name "Solid Spec3700"), and total light reflectance was measured using an integrating sphere. (Measurement conditions) ·Measurement wavelength: 240~2500nm, Scan speed: Medium, Slit width: 20nm, Sampling pitch: 1.0nm Standard white plate: Standard reflector Spectralon (manufactured by Labsphere).

[0045] [Example 1] 3.18 g (0.03 mol) of sodium carbonate (Na2CO3, molecular weight 105.99, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was weighed out using an analytical balance (Shimadzu Corporation, product name "ATX224") and dissolved in 300 mL of ultrapure water (Milli-Q water) collected in a measuring cylinder by stirring at 700 rpm for 10 minutes at room temperature (20°C) using a 2 cm long stirring bar and a hot stirrer (AS ONE Corporation, product name "REXIM RSH-10") to prepare a 0.1 M sodium carbonate aqueous solution (S3). Subsequent reagents were dissolved in ultrapure water in the same manner. A mixed solution of aluminum and copper (S12) (0.05M Al(NO3)3·9H2O + 0.15M CuCl2·2H2O) was prepared by dissolving 1.88g (0.005mol) of aluminum nitrate nonahydrate (Al(NO3)3·9H2O, molecular weight 375.13, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) and 2.56g (0.015mol) of copper(II) chloride dihydrate (CuCl2·2H2O, molecular weight 170.48, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) in 100mL of ultrapure water (Milli-Q water). In addition, 8.00 g of sodium hydroxide (NaOH, molecular weight 40.00, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 100 mL of ultrapure water (Milli-Q water) to prepare a 2 M aqueous sodium hydroxide solution.

[0046] The aluminum and copper mixed solution was added dropwise using a burette at a rate of 10±0.5 mL / min while stirring the sodium carbonate aqueous solution at room temperature (20°C) at 700 rpm using a 2 cm long stir bar and hot stirrer. During the addition of the mixed solution, sodium hydroxide aqueous solution was added appropriately to adjust the pH at 20°C to 10.0±0.2. After the addition of the mixed solution was completed, the hot stirrer was set to 90°C and 700 rpm to maintain the reaction solution at 65°C, and the mixture was stirred for 20 hours to obtain a precipitate. The color of the reaction solution was a cloudy light blue before 20 hours of stirring, but turned black after 20 hours of stirring. The temperature of the reaction solution after 20 hours of stirring was 63.8°C. The black precipitate was separated into solid and liquid by suction filtration through filter paper (5C, AS ONE Corporation) using an aspirator equipped with a funnel and suction bell (Tokyo Rikakikai Co., Ltd., product name "A-3S, EYELA") and washed three times with 200 mL of ultrapure water (Milli-Q water). The resulting reaction product was dried at 80 °C for 38 hours in a programmable constant temperature dryer (AS ONE Corporation, product name "DO-300PC") and then crushed in an agate mortar to obtain copper-containing layered double hydroxide (A). In this example, a pH meter (manufactured by Horiba Ltd., product name "D-51") was used for pH measurement. Ultrapure water (Milli-Q water) was collected from an ultrapure water production system (manufactured by Merck Ltd., product name "Direct-Q") and used.

[0047] The obtained copper-containing layered double hydroxide (A) was subjected to energy dispersive X-ray analysis (EDX), and the EDX spectrum is shown in Figure 1. Furthermore, the copper-containing layered double hydroxide (A) was measured by powder X-ray diffraction (XRD), and the results are shown in FIG. Furthermore, copper(II) oxide was measured by powder X-ray diffraction (XRD), and the results are shown in Figure 2.

[0048] [Example 2] 1.59 g (0.015 mol) of sodium carbonate (Na2CO3, molecular weight 105.99, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was weighed out using an analytical balance (Shimadzu Corporation, product name "ATX224") and dissolved in 150 mL of ultrapure water (Milli-Q water) collected in a measuring cylinder by stirring at 700 rpm for 10 minutes at room temperature (20°C) using a 2 cm long stirring bar and a hot stirrer (AS ONE Corporation, product name "REXIM RSH-10") to prepare a 0.1 M sodium carbonate aqueous solution (S3). Subsequent reagents were dissolved in ultrapure water in the same manner. A mixed solution of aluminum and copper (S12) (0.1 M Al(NO3)3·9H2O + 0.2 M CuCl2·2H2O) was prepared by dissolving 1.88 g (0.005 mol) of aluminum nitrate nonahydrate (Al(NO3)3·9H2O, molecular weight 375.13, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) and 1.71 g (0.01 mol) of copper(II) chloride dihydrate (CuCl2·2H2O, molecular weight 170.48, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) in 50 mL of ultrapure water (Milli-Q water). In addition, 4.01 g of sodium hydroxide (NaOH, molecular weight 40.00, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 50 mL of ultrapure water (Milli-Q water) to prepare a 2 M aqueous sodium hydroxide solution.

[0049] The aqueous sodium carbonate solution was stirred at room temperature (20°C) at 700 rpm using a 2 cm long stir bar and a hot stirrer, while the aluminum and copper mixed solution was added dropwise using a burette at a rate of 10 ± 0.5 mL / min. During the dropwise addition of the mixed solution, an aqueous sodium hydroxide solution was added appropriately so that the pH at 20°C was 10.0 ± 0.2. After the dropwise addition of the mixed solution was completed, the hot stirrer was set to 46°C and 700 rpm to maintain the reaction solution at 40°C, and the mixture was stirred for 22 hours to obtain a precipitate. The color of the reaction solution remained unchanged before and after 22 hours of stirring, remaining a cloudy light blue. The temperature of the reaction solution after 22 hours of stirring was 39.9°C. The cloudy white precipitate was separated into solid and liquid by suction filtration through filter paper (5C, AS ONE Corporation) using an aspirator equipped with a funnel and suction bell (Tokyo Rikakikai Co., Ltd., product name "A-3S, EYELA") and washed three times with 200 mL of ultrapure water (Milli-Q water). The resulting reaction product was dried at 50 °C for 26 hours in a programmable constant temperature dryer (AS ONE Corporation, product name "DO-300PC") and then crushed in an agate mortar to obtain copper-containing layered double hydroxide (B).

[0050] The copper-containing layered double hydroxide (B) thus obtained was subjected to powder X-ray diffraction (XRD) measurement, and the results are shown in FIG. Furthermore, the copper-containing layered double hydroxide (B) was measured by Fourier transform infrared spectroscopy (FT-IR), and the results are shown in Figure 3. Furthermore, the copper-containing layered double hydroxide (B) was subjected to composition analysis, and the results are shown in Table 1. A hydrogen sulfide adsorption test was also conducted on copper-containing layered double hydroxide (B). Table 2 shows the time-dependent changes in the total HS concentration in the HS water and headspace in a sealed container after adding copper-containing layered double hydroxide (B) to 15-fold diluted HS water. Figure 4 shows the rate of change in the total HS concentration in the container after adding copper-containing layered double hydroxide (B), assuming the total HS concentration in the sealed container before adding copper-containing layered double hydroxide (B) to be 100%. Figure 5 also shows the time-dependent changes in the HS concentration in the HS water and headspace in a sealed container after adding copper-containing layered double hydroxide (B).

[0051] [Example 3] 1.59 g (0.015 mol) of sodium carbonate (Na2CO3, molecular weight 105.99, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was weighed out using an analytical balance (Shimadzu Corporation, product name "ATX224") and dissolved in 150 mL of ultrapure water (Milli-Q water) collected in a measuring cylinder by stirring at 700 rpm for 10 minutes at room temperature (20°C) using a 2 cm long stirring bar and a hot stirrer (AS ONE Corporation, product name "REXIM RSH-10") to prepare a 0.1 M sodium carbonate aqueous solution (S3). Subsequent reagents were dissolved in ultrapure water in the same manner. A mixed solution of aluminum and copper (S12) (0.1 M Al(NO3)3·9H2O + 0.2 M CuCl2·2H2O) was prepared by dissolving 1.87 g (0.005 mol) of aluminum nitrate nonahydrate (Al(NO3)3·9H2O, molecular weight 375.13, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) and 1.70 g (0.01 mol) of copper(II) chloride dihydrate (CuCl2·2H2O, molecular weight 170.48, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) in 50 mL of ultrapure water (Milli-Q water). In addition, 4.02 g of sodium hydroxide (NaOH, molecular weight 40.00, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 50 mL of ultrapure water (Milli-Q water) to prepare a 2 M aqueous sodium hydroxide solution.

[0052] The aqueous sodium carbonate solution was stirred at room temperature (20°C) at 700 rpm using a 2 cm long stir bar and a hot stirrer, while the aluminum and copper mixed solution was added dropwise using a burette at a rate of 10 ± 0.5 mL / min. During the dropwise addition of the mixed solution, an aqueous sodium hydroxide solution was added appropriately to adjust the pH at 20°C to 10.0 ± 0.2. After the dropwise addition of the mixed solution was completed, the hot stirrer was set to 71°C and 700 rpm to maintain the temperature of the reaction solution at 50°C, and the mixture was stirred for 22 hours to obtain a precipitate. The color of the reaction solution remained unchanged before and after 22 hours of stirring, remaining a cloudy light blue. The temperature of the reaction solution after 22 hours of stirring was 49.7°C. The cloudy white precipitate was separated into solid and liquid by suction filtration through filter paper (5C, AS ONE Corporation) using an aspirator equipped with a funnel and suction bell (Tokyo Rikakikai Co., Ltd., product name "A-3S, EYELA") and washed three times with 200 mL of ultrapure water (Milli-Q water). The resulting reaction product was dried at 50 °C for 5 hours in a programmable constant temperature dryer (AS ONE Corporation, product name "DO-300PC") and then crushed in an agate mortar to obtain copper-containing layered double hydroxide (C).

[0053] The copper-containing layered double hydroxide (C) thus obtained was subjected to powder X-ray diffraction (XRD) measurement, and the results are shown in FIG. Furthermore, the copper-containing layered double hydroxide (C) was measured by Fourier transform infrared spectroscopy (FT-IR), and the results are shown in Figure 3. Furthermore, the copper-containing layered double hydroxide (C) was subjected to composition analysis, and the results are shown in Table 1. A hydrogen sulfide adsorption test was also conducted on copper-containing layered double hydroxide (C). Table 2 shows the time-dependent changes in the total HS concentration in the HS water and headspace in a sealed container after adding copper-containing layered double hydroxide (C) to 15-fold diluted HS water. Figure 4 shows the rate of change in the total HS concentration in the container after adding copper-containing layered double hydroxide (C), assuming the total HS concentration in the sealed container before adding copper-containing layered double hydroxide (C) to be 100%. Figure 6 shows the time-dependent changes in the HS concentration in the HS water and headspace in a sealed container after adding copper-containing layered double hydroxide (C).

[0054] [Example 4] 1.7532 g (0.03 mol) of sodium chloride (NaCl, molecular weight 58.44, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was weighed out using an analytical balance (Shimadzu Corporation, product name "ATX224") and dissolved in 300 mL of ultrapure water (Milli-Q water) collected in a measuring cylinder by stirring at 700 rpm for 10 minutes at room temperature (20°C) using a 2 cm long stirring bar and a hot stirrer (AS ONE Corporation, product name "REXIM RSH-10") to prepare a 0.1 M sodium chloride aqueous solution (S3). Subsequent reagents were dissolved in ultrapure water in the same manner. A mixed solution of aluminum and copper (II) chloride (0.05 M AlCl3·6H2O + 0.15 M CuCl2·2H2O) was prepared as aqueous solution (S12) by dissolving 1.2072 g (0.005 mol) of aluminum chloride hexahydrate (AlCl3·6H2O, molecular weight 241.43, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) and 2.5573 g (0.015 mol) of copper (II) chloride dihydrate (CuCl2·2H2O, molecular weight 170.48, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) in 100 mL of ultrapure water (Milli-Q water). In addition, 4.02 g of sodium hydroxide (NaOH, molecular weight 40.00, special grade, Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 50 mL of ultrapure water (Milli-Q water) to prepare a 2 M aqueous sodium hydroxide solution.

[0055] The aluminum and copper mixed solution was added dropwise using a burette at a rate of 10±0.5 mL / min while stirring the sodium chloride aqueous solution at room temperature (20°C) at 700 rpm using a 2 cm long stir bar and hot stirrer. During the addition of the mixed solution, sodium hydroxide aqueous solution was added appropriately to adjust the pH at 20°C to 10.0±0.2. After the addition of the mixed solution was completed, the hot stirrer was set to 46°C and 700 rpm to maintain the reaction solution at 40°C, and the mixture was stirred for 20 hours to obtain a precipitate. The color of the reaction solution remained unchanged before and after 20 hours of stirring, remaining a cloudy light blue. The temperature of the reaction solution after 20 hours of stirring was 39.9°C. The cloudy white precipitate was separated into solid and liquid by suction filtration through filter paper (5C, AS ONE Corporation) using an aspirator equipped with a funnel and suction bell (Tokyo Rikakikai Co., Ltd., product name "A-3S, EYELA") and washed three times with 200 mL of ultrapure water (Milli-Q water). The resulting reaction product was dried at 50 °C for 26 hours in a programmable constant temperature dryer (AS ONE Corporation, product name "DO-300PC") and then crushed in an agate mortar to obtain copper-containing layered double hydroxide (D).

[0056] The obtained copper-containing layered double hydroxide (D) was measured by ultraviolet-visible spectroscopy, and the results are shown in Figure 7.

[0057] [Table 1]

[0058] [Table 2]

[0059] As is clear from the results in Figure 1, the peak of Cu-Al hydrotalcite was confirmed. In addition, the copper-containing layered double hydroxide (B) obtained in Example 2, the copper-containing layered double hydroxide (C) obtained in Example 3, and the copper-containing layered double hydroxide (D) obtained in Example 4 also exhibited absorption peaks roughly similar to those in Example 1.

[0060] As is clear from the results in Figure 2, in the case of Example 1, in addition to the peaks attributable to the copper-containing layered double hydroxide, peaks attributable to copper oxide (CuO) were also observed. This means that the by-product copper oxide was produced in addition to the copper-containing layered double hydroxide. On the other hand, in the cases of Examples 2 and 3, almost no peaks attributable to copper oxide (CuO) were observed. These results indicate that a lower stirring temperature can suppress the production of the by-product copper oxide. Furthermore, copper oxide is a black solid, and in the case of Example 1, the color of the reaction solution turned black after 20 hours of stirring, suggesting that the copper-containing layered double hydroxide and copper oxide were present together in the reaction solution. The copper-containing layered double hydroxide (D) obtained in Example 4 also exhibits roughly the same absorption peaks as those in Example 2.

[0061] As is clear from the results in Figure 3, -1 The absorption peaks around 2850-2950 cm are due to the stretching and bending motion of the hydrogen bonds of the hydroxyl groups. -1 The absorption peak at 1360 cm is due to the hydrogen bond between the interlayer water and the anion. -1 , 1060cm -1 , 818cm -1 The absorption peak at 1070 cm is due to carbonate ions. -1 , 1190cm -1 The absorption peaks at 620 cm are due to the vibration of Al-OH and Cu-OH bonds, respectively. -1 , 847cm -1 The absorption peak seen around 458 cm is due to the vibration of the Al-O bond. -1 The absorption peak at 753 cm is due to the vibration of the Cu-O bond. -1 The absorption peaks observed around this area are due to MO, MOM, or OMO (M is Cu or Al). Therefore, from the results of FIG. 3 and Table 1, it can be seen that the copper-containing layered double hydroxide (B) obtained in Example 2 contains Cu. 1-x Al x (OH)2A n- x / n mH2O(A n- : Carbonate ion (CO32- ), x: 0.31). In addition, the copper-containing layered double hydroxide (C) obtained in Example 3 was found to have a Cu 1-x Al x (OH)2A n- x / n mH2O(A n- : Carbonate ion (CO3 2- ), x:0.33), where x is approximately the same as the ratio of the number of Cu and Al atoms used in the production. The copper-containing layered double hydroxide (A) obtained in Example 1 was also measured by Fourier transform infrared spectroscopy (FT-IR), and the absorption peaks roughly the same as those in Examples 2 and 3 were observed.

[0062] Furthermore, as is clear from the results in Figures 4 to 6, when copper-containing layered double hydroxide (B) or copper-containing layered double hydroxide (C) was added to HS water, the HS concentration in the headspace quickly became zero. The total HS concentration in the container decreased to about 40% for both copper-containing layered double hydroxide (B) and copper-containing layered double hydroxide (C). This indicates that copper-containing layered double hydroxide (B) and copper-containing layered double hydroxide (C) have the effect of attenuating HS, and that there is no difference in the amount of HS adsorption due to differences in stirring temperature. The copper-containing layered double hydroxide (A) obtained in Example 1 and the copper-containing layered double hydroxide (D) obtained in Example 4 also have the same H2S attenuation effect as the copper-containing layered double hydroxide (B) and the copper-containing layered double hydroxide (C).

[0063] Furthermore, as is clear from the results in FIG. 7, the copper-containing layered double hydroxide (D) exhibited absorption in the ultraviolet region, indicating that it has ultraviolet absorbing ability. Furthermore, the copper-containing layered double hydroxide (A) obtained in Example 1, the copper-containing layered double hydroxide (B) obtained in Example 2, the copper-containing layered double hydroxide (C) obtained in Example 3, and the copper-containing layered double hydroxide (D) obtained in Example 4 possessed antibacterial properties. [Industrial Applicability]

[0064] The copper-containing layered double hydroxide of the present invention has a new function in addition to its function of adsorbing volatile sulfur compounds, and is useful as a deodorant, antibacterial agent, ultraviolet absorber, or an active ingredient thereof.

Claims

1. A copper-containing layered double hydroxide represented by the following general formula (1): Cổ １－ｘ Al ｘ (OH) ２ A ｎ－ ｘ／ｎ ・mH ２ O ・・・(1) (In formula (1), A ｎ－ is a chloride ion, x is a number satisfying 0<x<1, n is 1, and m is a number satisfying 0<m.

2. A deodorant composition comprising the copper-containing layered double hydroxide according to claim 1.

3. An antibacterial composition comprising the copper-containing layered double hydroxide of claim 1.

4. An ultraviolet absorber composition comprising the copper-containing layered double hydroxide according to claim 1.

5. A method for producing the copper-containing layered double hydroxide according to claim 1, comprising the steps of: A method for producing a copper-containing layered double hydroxide, comprising reacting an aqueous solution containing copper with an aqueous solution containing aluminum under conditions where the pH is 8 or higher.

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