JP5423053B2 - Method for producing fatty acid-modified metal ultrafine particle dispersion - Google Patents

Description

  The present invention relates to a method for producing a fatty acid-modified metal ultrafine particle dispersion, and more specifically, the fatty acid-modified metal ultrafine particles can be produced in the dispersion with good dispersion stability, and have an excellent adsorption effect and fine protein resistance. The present invention relates to a method for producing a dispersion of fatty acid-modified metal ultrafine particles capable of having an activating effect.

Ultra-fine metal particles, especially ultra-fine metal particles with a particle diameter of 100 nm or less, are very different in characteristics from general metal particles, and their surface activity is particularly large, so they are proposed for use in various fields such as catalysts and adsorbents. Has been.
Particularly in applications such as deodorants and antibacterial agents, it is prepared in the form of a dispersion obtained by dispersing ultrafine metal particles in a solvent, and this dispersion is directly sprayed, applied or impregnated. . As a dispersion liquid in which ultrafine metal particles are dispersed, for example, a deodorant (Patent Document 1) containing an ultrafine metal particle colloid liquid obtained by reducing a metal ion-containing liquid as an active ingredient has been proposed. The colloidal dispersion liquid as described above is not satisfactory in terms of handling properties.

  Further, in Patent Document 2 below, silver obtained by mixing a silver salt, polyethylene glycol having an average molecular weight of 400 to 20,000, and a stabilizer and re-dispersing silver ultrafine particles generated by heating in a dispersion medium. Ultrafine particle dispersions have been proposed.

JP 2006-109902 A JP 2006-348345 A

  However, in the above-described dispersion of ultrafine metal particles, powdery ultrafine metal particles are produced in advance and redispersed in a dispersion medium, and a dispersion of ultrafine metal particles is directly produced. Therefore, a dispersion cannot be efficiently prepared. Furthermore, since an odor component such as ammonia is used in the production process of the ultrafine metal particles, it cannot be used as a deodorant as it is or as a dispersion liquid.

  The present inventors inactivate malodorous components such as methyl mercaptan or adsorbent metal ultrafine particles capable of adsorbing volatile organic compounds (hereinafter referred to as “VOC”) such as formaldehyde, and minute proteins such as allergens. Proposed fine protein-inactivated metal ultrafine particles have already been proposed (Japanese Patent Application No. 2006-332077 and Japanese Patent Application No. 2006-237898), which are heated in a resin or in a paint to form a resin molding or coating. Although the metal ultrafine particles can be uniformly dispersed in the film, the dispersion cannot be efficiently prepared, and it is efficient if the dispersion can also be produced directly.

Accordingly, an object of the present invention is to provide a method for producing a dispersion of fatty acid-modified metal ultrafine particles having excellent dispersion stability.
Another object of the present invention is to provide a method for producing a dispersion, in which the produced dispersion can be used as it is or after being diluted.

According to the present invention, the polyvalent metal in alcohol, a fatty acid metal salt is silver or copper least one included in an amount of 1 × 10 -6 ^{to 20%} by weight, the fatty acid metal salt and the multivalent Dispersion characterized in that the fatty acid metal salt is mixed and heated at a temperature at which the fatty acid metal salt is thermally decomposed in the polyhydric alcohol and at a temperature not higher than the boiling point of the polyhydric alcohol to produce fatty acid-modified metal ultrafine particles in the polyhydric alcohol. A method for producing a liquid is provided.
In the method for producing the dispersion of the present invention,
1 . The average particle diameter before Symbol fatty acid metal salt is 1 to 100 [mu] m,
2 . 1 to the 100nm Dearuko average particle size of the fatty acid-modified metal ultrafine particles,
3 . The polyhydric alcohol is at least one of polyethylene glycol, diethylene glycol, and glycerol;
4 . The average molecular weight of polyethylene glycol is 400 to 20000,
5 . The fatty acid is one or more of myristic acid, stearic acid and palmitic acid,
6 . Further blending an antioxidant,
Is preferred.

According to the present invention, there is also provided a dispersion obtained by diluting the dispersion produced by the above production method with water or a low boiling point solvent.
The present invention further provides an adsorbent or a microprotein deactivator comprising the above dispersion.

In the method for producing a dispersion of the present invention, a dispersion in which fatty acid-modified metal ultrafine particles are dispersed in a polyhydric alcohol can be prepared by mixing and heating a fatty acid metal salt and a polyhydric alcohol.
The fatty acid-modified metal ultrafine particles present in the dispersion prepared by the production method of the present invention have a bond between the fatty acid and the metal, and the fatty acid is bonded to the surface of the metal ultrafine particle. Unlike the surface coated with fatty acid, a part of the surface of the ultrafine metal particles is exposed. Thereby, it is possible to obtain a dispersion containing ultrafine metal particles having excellent handling properties without impairing the excellent adsorption performance or fine protein inactivation performance of ultrafine metal particles.
Whether or not the metal ultrafine particles have a bond between the organic acid component and the metal is clear by examining the infrared absorption peak. In the present invention, the organic acid and the metal are located near 1518 cm ^−1. It becomes clear that the ultrafine metal particles have a bond between the organic acid component and the metal by having an infrared absorption peak derived from the bond between them (COO-M).

In the method for producing a dispersion of the present invention, ultrafine metal particles and uniform dispersion can be performed together with the preparation of the dispersion, and the dispersion stability of the ultrafine metal particles in the resulting dispersion is excellent.
Further, the dispersion obtained by the production method of the present invention is an adsorbent capable of effectively adsorbing malodor components such as methyl mercaptan or VOC such as formaldehyde by diluting the dispersion as it is or with water or a low-boiling solvent. Can be used as
Furthermore, the dispersion obtained by the production method of the present invention has a specific three-dimensional structure depending on the bacteria, fungi, amino acid sequence, in addition to bacteria and allergen substances, by diluting the dispersion as it is or with water or a low-boiling solvent. Enzymes or microproteins such as viruses, which are particulate substances consisting of DNA or RNA (nucleic acid) and a small number of protein molecules, can also be used as dispersions that can be effectively inactivated.

(Fatty acid metal salt)
The metal component in the fatty acid metal salt used in the method for producing the dispersion of the present invention is not particularly limited, but Cu, Ag, Au, In, Pd, Pt, Fe, Ni, Co, Nb, Ru, Rh, Sn Among them, Au, Ag, Cu, Pt, Sn, particularly Ag is preferable.
In addition, as fatty acids, aliphatic carboxylic acids such as myristic acid, stearic acid, oleic acid, palmitic acid, n-decanoic acid, paratoic acid, succinic acid, malonic acid, tartaric acid, malic acid, glutaric acid, adipic acid, acetic acid, Examples include alicyclic carboxylic acids such as cyclohexanedicarboxylic acid.
In the present invention, the fatty acid to be used is particularly preferably a higher fatty acid having 3 to 30 carbon atoms such as myristic acid, stearic acid, and palmitic acid. Or VOC can be adsorb | sucked and it becomes possible to improve the adsorption effect (deodorizing effect) more.
Examples of the most suitable fatty acid metal salt include silver myristate, silver stearate and the like, and an average particle diameter of 1 to 100 μm, particularly 20 to 80 μm is uniformly dispersed in the polyhydric alcohol. This is preferable.

(Polyhydric alcohol)
The polyhydric alcohol used in the production method of the present invention preferably has a boiling point higher than the temperature at which the fatty acid metal salt used is thermally decomposed in the polyhydric alcohol, and examples thereof include polyethylene glycol, diethylene glycol, and glycerol. In particular, polyethylene glycol can be preferably used.
Polyethylene glycol having an average molecular weight of 200 to 20000, particularly 400 to 10,000 can be suitably used, and plural kinds of polyethylene glycol having different molecular weights can be mixed and used.

(Production method)
In the method for producing a dispersion according to the present invention, it is preferable to blend a fatty acid metal salt in a polyhydric alcohol in an amount of 1 × 10 ^{−6 to} 20 wt%, particularly 1 × 10 ^{−5 to} 5 wt%. If the amount of the fatty acid metal salt is less than the above range, a sufficient amount of the fatty acid-modified metal ultrafine particles cannot be dispersed. On the other hand, if it exceeds the above range, the fatty acid-modified metal ultrafine particles may be aggregated.
Moreover, it is preferable to mix | blend antioxidant as a protective agent, and it becomes possible to prevent the thermal deterioration at the time of a heating by mix | blending antioxidant.
Examples of the antioxidant to be used include, but are not limited to, tocopherols (vitamin E), hindered phenol antioxidants, phosphorus antioxidants, ethylenebisstearic acid amides and the like. However, Irganox 1010 (registered trademark: manufactured by Ciba Specialty Chemicals Co., Ltd.) can be preferably used. The antioxidant is preferably blended in the polyhydric alcohol in an amount of 0.01 to 20% by weight.

In the method for producing a dispersion according to the present invention, after blending a fatty acid metal salt and, if necessary, an antioxidant in the polyhydric alcohol, the temperature at which the fatty acid metal salt is thermally decomposed in the polyhydric alcohol, and the boiling point of the polyhydric alcohol While heating at a temperature below, the mixture is stirred and mixed to produce fatty acid-modified metal ultrafine particles in a polyhydric alcohol. The temperature at which the fatty acid metal salt is thermally decomposed is equal to or higher than the decomposition start temperature of the fatty acid metal salt, but the heating temperature can be adjusted by the stirring and mixing time. Incidentally, the decomposition start temperature of the fatty acid metal salt is a temperature at which the fatty acid portion begins to desorb or decompose from the metal portion, and the start temperature is generally defined by JIS K 7120. According to this, the mass of the organic compound (fatty acid metal salt) is measured, and thermogravimetry (TG) is performed to measure the change in weight when the temperature is raised in an inert atmosphere using a thermogravimetry apparatus. The decomposition start temperature is calculated from the thermogravimetric curve (TG curve) obtained by the measurement. It is defined that the temperature at the point where the line parallel to the horizontal axis passing through the mass before the start of test heating and the tangent line at which the gradient between the bending points in the TG curve becomes maximum is the starting temperature.
The heating time varies depending on the type of polyhydric alcohol used and the blending amount of the fatty acid metal salt, and cannot be generally defined, but it is preferable to heat in the range of 1 to 1800 seconds, particularly 5 to 300 seconds.
After heating and mixing, the mixture is cooled at room temperature, and the polyhydric alcohol solution is filtered. Thereby, the free fatty acid in the polyhydric alcohol can be removed, and a dispersion liquid in which the fatty acid-modified metal ultrafine particles of the present invention are dispersed in the polyhydric alcohol can be obtained.
The average particle size of the fatty acid-modified metal ultrafine particles is preferably 1 to 100 nm from the viewpoint of improving the adsorptivity and protein inactivation.
Whether or not the fatty acid-modified metal ultrafine particles are uniformly dispersed in the polyhydric alcohol can be confirmed by the presence of plasmon absorption of the metal ultrafine particles. For example, when the fatty acid metal salt used in the preparation of the dispersion is silver stearate, a peak is obtained in the vicinity of 400 to 450 nm, and it is confirmed that the ultrafine silver particles are uniformly dispersed in polyethylene glycol. it can.

(Dispersion)
The dispersion obtained by the production method of the present invention can be used as an adsorbent (deodorant) or a microprotein inactivator as it is, but is preferably diluted with a solvent.
The solvent used for dilution is not limited to this, but water such as purified water and ion-exchanged water; lower alcohols such as methanol, ethanol, propanol, isopropanol, and butanol; methanol-modified, benzol-modified, triol-modified, methyl ethyl ketone-modified, benzoic acid General modified alcohols such as acid denatonium modification and perfume modification; modified alcohols such as ethylene glycol monoethyl ether, chloroform, diethyl carbonate, ethyl acetate, ethyl propionate, ethyl butyrate, hexane, industrial ethyl ether; ethylene glycol monobutyl ether, diethylene glycol Monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol Le diethylene glycol monobutyl ether, dipropylene glycol ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, and glycol solvents such as triethylene glycol monophenyl ether. These solvents may be used alone or in combination of two or more.
In the present invention, a low-boiling solvent having a boiling point of 78 ° C. or lower such as water or ethanol can be preferably used, and an ethanol aqueous solution having a concentration of 1 to 30% can be particularly preferably used.

When the dispersant of the present invention is used as a deodorant, the fatty acid-modified metal ultrafine particles are preferably contained in an amount of 1 × 10 ^{−6 to} 20% by weight, and when used as an adsorbent for VOC. The fatty acid-modified metal ultrafine particles are preferably contained in an amount of 1 × 10 ^{−6 to} 20% by weight, and when used as a microprotein deactivator, the fatty acid-modified metal ultrafine particles are 1 × 10 6 It is preferably contained in an amount of ^{-6 to} 20% by weight.
The dispersant of the present invention is used by spraying, coating, impregnating, etc., on housing-related members such as floors, wall surfaces, curtains and carpets, air-conditioning equipment, textile products such as woven fabrics and nonwoven fabrics, and filtering members such as masks and filters. be able to.

1. Confirmation of Plasmon Absorption by Measuring Spectral Transmittance of Dispersion About the dispersion, the spectral transmittance was measured using a spectrophotometer (Shimadzu UV-3100PC) to confirm the presence or absence of plasmon absorption at 300 to 700 nm.

2. Measurement of undeodorized methyl mercaptan concentration Adjusted to a concentration of 1.4 ppm in a 500 mL glass bottle (GL-Science) with nitrogen gas replacement with a mouth sealed with a rubber stopper. The malodorous methyl mercaptan (5 μL) was injected with a micro syringe and left at room temperature (25 ° C.) for 1 day. After leaving for one day, a detector tube manufactured by Gastec Co., Ltd. was inserted into the bottle, and the residual methyl mercaptan concentration was measured to determine the methyl mercaptan concentration (A) when not deodorized.

3. Measurement of methyl mercaptan concentration after deodorization Weighed 200 μL of the dispersion, put it in a 500 mL glass bottle (GL-Science) substituted with nitrogen gas, sealed with a rubber stopper, and then the concentration in the bottle was 1.4 ppm. The malodorous methylmercaptan aqueous solution 5 μL adjusted to become was injected with a microsyringe and left at room temperature (25 ° C.) for 1 day. After leaving for 1 day, a detector tube manufactured by Gastec Co., Ltd. was inserted into the bottle, the residual methyl mercaptan concentration was measured, and the deodorized methyl mercaptan concentration (B) was obtained.

4). Calculation of methyl mercaptan deodorization rate The value obtained by dividing the undeodorized methyl mercaptan concentration (A) by the deodorized methyl mercaptan concentration (B) and the undeodorized methyl mercaptan concentration (A) as a percentage. Was defined as a deodorization rate.

[Example 1]
Disperse 10 mL of polyethylene glycol 400 in a solution preheated to 220 ° C. so that silver stearate is 5 ppm, stir and mix at the same temperature, immediately cool, and then filter using a filter to disperse. A liquid was obtained. About the obtained dispersion liquid, confirmation of the plasmon absorption mentioned above, the measurement of the methyl mercaptan density | concentration, and calculation of the deodorizing rate were performed.

[Example 2]
The above-described confirmation, measurement, and calculation were performed on the dispersion in the same manner as in Example 1 except that silver stearate was blended to 10 ppm.

[Example 3]
The above-described confirmation, measurement, and calculation were performed on the dispersion in the same manner as in Example 1 except that silver stearate was blended to 20 ppm.

[Example 4]
The above-described confirmation, measurement, and calculation of the dispersion were performed in the same manner as in Example 1 except that silver myristate was blended to 20 ppm.

[Example 5]
The above-described confirmation, measurement and calculation of the dispersion were performed in the same manner as in Example 1 except that 10 mL of diethylene glycol was mixed in advance at 200 ° C. so that silver stearate was added to 5 ppm.

[Example 6]
The above-described confirmation, measurement, and calculation were performed on the dispersion in the same manner as in Example 1 except that 10 mL of glycerol was preliminarily heated to 200 ° C., and silver stearate was blended to 5 ppm.

[Comparative Example 1]
The above-described confirmation, measurement, and calculation were performed on the dispersion liquid in the same manner as in Example 1 except that 10 mL of polyethylene glycol 400 was blended in a solution heated to 100 ° C. in advance so that silver stearate was 5 ppm. .

[Comparative Example 2]
The confirmation, measurement, and calculation described above for the dispersion were performed in the same manner as in Example 1 except that 10 mg of stearyl alcohol was previously heated to 200 ° C. and melted, and silver stearate was blended to 5 ppm.

[Comparative Example 3]
The above-mentioned confirmation, measurement and calculation were performed on the dispersion liquid in the same manner as in Example 1, except that 10 mg of myristic acid was previously melted by heating to 200 ° C. and silver stearate was blended to 5 ppm.

The results are shown in Table 1.

Claims (10)

A fatty acid metal salt in which the metal is one or more of silver or copper is blended in an amount of 1 × 10 ^{−6 to} 20% by weight in the polyhydric alcohol, and the fatty acid metal salt and the polyhydric alcohol are mixed with the fatty acid metal salt. A method for producing a dispersion, wherein the fatty acid-modified metal ultrafine particles are produced in a polyhydric alcohol by mixing and heating at a temperature at which the oil is thermally decomposed in the polyhydric alcohol and a temperature not higher than the boiling point of the polyhydric alcohol . The method for producing a dispersion according to claim 1, wherein the fatty acid metal salt has an average particle diameter of 1 to 100 μm. The method for producing a dispersion according to claim 1 or 2 , wherein the fatty acid-modified ultrafine metal particles have an average particle diameter of 1 to 100 nm. The method for producing a dispersion according to any one of claims 1 to 3 , wherein the polyhydric alcohol is at least one of polyethylene glycol, diethylene glycol, and glycerol. The method for producing a dispersion according to claim 4 , wherein the polyethylene glycol has an average molecular weight of 200 to 20000. The method for producing a dispersion according to any one of claims 1 to 5 , wherein the fatty acid is one or more of myristic acid, stearic acid, and palmitic acid. The method for producing a dispersion according to any one of claims 1 to 6 , further comprising an antioxidant. Dispersions, characterized in that the dispersions prepared by either method of claims 1 to 7, formed by diluting with water or a low-boiling solvent. An adsorbent comprising the dispersion according to claim 8 . A microprotein inactivating agent comprising the dispersion according to claim 8 .