JP5075708B2 - Method for producing fine particle dispersion, fine particle dispersion of metal or metal compound produced using the same, and fine particle dispersion obtained by replacing it with dispersion medium - Google Patents

Description

  The present invention relates to a method for producing a fine particle dispersion, and more specifically, when a metal gas or a metal compound dispersion is produced by a specific method, a specific compound is dissolved in a dispersion medium, thereby reducing the size of the dispersion. The present invention relates to a method for producing a fine particle dispersion in which the dispersibility, dispersion stability and the like of fine particles having a particle size are greatly improved.

  Metal or fine particle dispersion of the metal compound is used for IC substrates, wiring of semiconductor elements, interlayer connection of semiconductor modules, formation of transparent conductive film, bonding of metal and nonmetal, color filter using colloid color of liquid, etc. Widely used in

  As a method for producing a metal or fine particle dispersion of the metal compound, a method of obtaining a dispersion of metal fine particles by reducing an aqueous solution of a metal compound in an oxidized state such as a metal salt with a reducing agent has been widely known. Yes. However, in such a chemical method, only a fine particle dispersion containing substances remaining without reduction or impurities due to a reduction reaction can be prepared, and its use is limited. In addition, regarding this method, many methods for improving the dispersibility by changing the kind of reducing agent used, the purity of the substance used, the presence or absence of protective colloid, the pH and temperature at the time of preparation, etc. have been studied. However, none of them has reached a sufficient dispersion stability.

  Unlike the above chemical methods, physical methods such as a spark erosion method, a gas evaporation method, and a vacuum deposition method are known.

  The spark erosion method is a method for producing a fine particle dispersion by using a metal or the like to be dispersed as electrodes and generating a discharge between the electrodes in a dispersion medium. However, in this method, since it is difficult to contain a surfactant that is a good electrical conductor in the dispersion medium, there are cases where aggregation of fine particles cannot be suppressed.

In the gas evaporation method, a vapor of a metal or a metal compound to be dispersed is generated in the presence of an inert gas of 0.1 to 30 Torr (mmHg) (1.3 × 10 ¹ Pa to 4 × 10 ³ Pa). In this method, fine particles are produced in a gas phase, and immediately after production, the fine particles are collected in a solvent to produce a fine particle dispersion (see Patent Document 1). There is also a method of producing a fine particle dispersion by obtaining fine particles dispersed in an organic substance by allowing an organic gas that is liquid at room temperature to coexist in an inert gas, and then performing solvent exchange or the like. Are known.

  However, in these gas evaporation methods, it is difficult to make the average particle diameter uniform. In other words, the generated metal or metal compound vapor is cooled by collision with an inert gas atom to form fine particles, but the generated fine particles are likely to associate again in the inert gas and form a cluster. There was a problem caused by contact with gas.

  The vacuum evaporation method deposits metal etc. on the surface of oil whose surface is covered with a surfactant etc., and metal atoms etc. aggregate to form fine particles, and at the same time, protect the fine particles with surfactant etc. This is a method for preventing the association between fine particles and obtaining a dispersion in which fine particles are dispersed in oil (see Patent Document 2). In this method, since the fine particles are directly generated in the liquid, the problems caused by the contact between the gas and the gas, the association between the fine particles, and the like, which are problems in the gas evaporation method, are hardly generated.

  However, little research has been conducted on the compounds to be dissolved such as the surfactant and the dispersant in the vacuum deposition method. In the succinimide polyamine used as the surfactant in Patent Document 2, fine particles are used. There were still problems such as the fact that they were associated before forming a cluster before being protected by the surfactant. Therefore, even if the vacuum deposition method, which is a relatively excellent method, is used, sufficient dispersibility and dispersion stability have not been imparted to the fine particle dispersion of metal, alloy or metal compound.

JP 2002-121606 A International Publication WO2005 / 099941

  The present invention has been made in view of the above-described background art, and its problem is that it can be dispersed with an extremely small particle diameter, and has good dispersibility, dispersion stability, high-concentration dispersibility, and the like. An object of the present invention is to provide a method for producing a fine particle dispersion of a compound. Further, a fine particle dispersion produced by using the production method, and a fine particle dispersion obtained by subjecting the fine particle dispersion to solvent substitution. It is to provide.

  As a result of intensive studies to solve the above problems, the present inventor has made a specific compound dissolved in a dispersion medium when a metal gas or a metal compound dispersion is produced by a specific method. The present inventors have found that the dispersibility and the like are improved and have completed the present invention.

  That is, according to the present invention, a metal, alloy, or metal compound gas is brought into contact with a low vapor pressure liquid so that the fine particles of the metal, alloy, or metal compound have a volume distribution median diameter (D50) of 100 nm or less in the low vapor pressure liquid. It is a method for producing a dispersed dispersion, and provides a method for producing a fine particle dispersion, wherein a fatty acid is dissolved in the low vapor pressure liquid.

  The present invention also provides a fine particle dispersion of a metal, alloy or metal compound produced using the above production method.

  The present invention also relates to a metal, alloy or metal compound obtained by substituting the low vapor pressure liquid in the “fine particle dispersion of metal, alloy or metal compound” with another dispersion medium. A fine particle dispersion is provided.

  According to the present invention, it is possible to disperse even to fine particles having an extremely small volume distribution median diameter (D50), and even when dispersed to a small particle size, the dispersibility is excellent, there is no aggregation of fine particles, and the dispersion is stable. It is possible to provide a “fine particle dispersion of metal, alloy or metal compound” which is also excellent in properties. Further, by replacing the obtained fine particle dispersion with a solvent, it is possible to provide a “fine particle dispersion of metal, alloy or metal compound” having excellent dispersibility.

  Hereinafter, the present invention will be described, but the present invention is not limited to the following specific embodiments, and can be arbitrarily modified within the scope of the gist of the invention.

  The present invention provides a metal gas, an alloy gas or a metal compound gas (hereinafter abbreviated as “metal gas”) by contacting the metal, the alloy or the metal compound with a low vapor pressure liquid. The present invention relates to a method for producing a dispersion in which the fine particles are dispersed in the low vapor pressure liquid. “Alloy gas” includes a mixed gas of a plurality of metals.

  The “metal, alloy or metal compound” (hereinafter abbreviated as “metals”) dispersed by the method of the present invention is not particularly limited as long as it becomes a gas by heating or the like. As the metals that become fine particles in the production method of the present invention, those that become non-crystalline particles in the fine particle state have high transparency due to low light scattering when dispersed in a dispersion medium, and achieve good dispersibility. It is preferable from the point that it can be melted at a low temperature. Specifically, for example, metals such as Ag, Cu, Sn, Pd, In, Au, Zn, Bi, Fe, lead, Ni, Al, and Pt, alloys containing them, or oxides and nitrides thereof And the like are particularly preferable.

  There is no particular limitation on the method of making the metals gaseous, and the metals are heated by a known heating method. The heating temperature is not particularly limited as long as it is sufficient to be in a gaseous state, and also varies depending on the type of metal, but is preferably 200 to 2000 ° C, more preferably 400 to 1800 ° C, and 600 to 1600 ° C. Is particularly preferable, and 800 to 1400 ° C is more preferable.

  In the present invention, a metal gas is brought into contact with a low vapor pressure liquid described later to form a dispersion. In this case, an inert gas such as helium, argon or nitrogen is dispersed in the metal gas; Although it does not exclude the coexistence of organic gases such as a medium and a dispersion aid, it is necessary to make them coexist from the principle of operation of the present invention in which a molecule is brought into contact with a liquid to create a dispersed state at a liquid phase interface. There is no sex. Preferably, the inert gas is not allowed to coexist.

There is no particular limitation on the pressure when forming a dispersion by bringing a metal gas into contact with a low vapor pressure liquid described later, but it is preferably 10 ⁻¹ Pa or less.

In these respects, the vapors of metals are aggregated by interaction with an inert gas under a pressure of 0.1 to 30 Torr (mmHg) (1.3 × 10 ¹ Pa to 4 × 10 ³ Pa). The present invention is based on a completely different technical idea from the above-described gas evaporation method in which fine particles are generated in a gas.

In the present invention, the pressure is preferably 10 ⁻¹ Pa or less, particularly preferably 10 ⁻² Pa or less. Moreover, it is preferable that it is 10 ^<-4 > Pa or more, and it is especially preferable that it is 10 ^<-3 > Pa or more. When the pressure is too high, that is, the degree of vacuum is poor, problems such as the need to increase the heating temperature and the influence of the gas intervening there may cause changes in the fine particles. If the pressure is too low, that is, if the degree of vacuum is unnecessarily high, the low vapor pressure liquid may volatilize, productivity may drop, or the vacuum pump may be overloaded.

In the present invention, "metal gas, alloy gas or metal compound gas" (metal gas) is brought into contact with a low vapor pressure liquid to disperse it in the low vapor pressure liquid. A “low vapor pressure liquid” refers to a liquid that has a low vapor pressure at the temperature at the time of dispersion and does not substantially volatilize at 10 ⁻³ Pa. If the vapor pressure is not low, the gas may evaporate and interact with the “metal gas, alloy gas or metal compound gas” to adversely affect dispersibility. The vapor pressure is preferably 10 ⁻¹⁰ Pa to ^{10 −5} Pa at 25 ° C., particularly preferably 10 ⁻⁸ Pa to 10 ⁻⁶ Pa at 25 ° C. The boiling point at 1 atm of such a low vapor pressure liquid is not particularly limited, but for the same reason as above, it is preferably 180 ° C. or higher, more preferably 200 ° C. or higher, particularly preferably 220 ° C. or higher, and further preferably 240 ° C. or higher. .

  Specifically, for example, aliphatic and / or aromatic hydrocarbons such as alkyl naphthalene and ethylene olefin copolymer; aromatic ethers such as alkyl diphenyl ether, polyphenyl ether and polyalkyl phenyl ether; silicone oil, poly Siloxane compounds such as alkylsiloxanes; fluorocarbon oils; polyhydric alcohols and the like. Here, the alkyl group is not particularly limited, but preferably has 4 to 24 carbon atoms, more preferably has 8 to 22 carbon atoms, and particularly preferably has 12 to 20 carbon atoms. In the case of “aliphatic and / or aromatic hydrocarbons”, the total number of carbon atoms is preferably 14 or more, more preferably 20 or more, and particularly preferably 25 or more. . These are used alone or in combination of two or more. A commercially available diffusion pump oil is also preferably used as the low vapor pressure liquid.

  In the method for producing a fine particle dispersion of the present invention, by bringing a gas into contact with a low vapor pressure liquid, the gas becomes solid fine particles and dispersed in the low vapor pressure liquid. The fatty acid is dissolved in the vapor pressure liquid. Dispersion particles having a small volume distribution median diameter (D50) can be formed by dissolving the fatty acid, and a dispersion having excellent dispersibility, dispersion stability, high concentration dispersibility, etc. even with a small particle size. Can be obtained.

  The fatty acid is not particularly limited as long as it has a carboxyl group and has a chain structure, and includes those having a linear structure and those having a side chain, and saturated fatty acids and unsaturated fatty acids are also included. Moreover, you may have a substituent in the range which does not impair the effect of this invention. Although there is no particular limitation, an unsaturated fatty acid is particularly preferable from the viewpoint of good solubility in a low vapor pressure liquid.

  The number of carbon atoms of the fatty acid used in the method for producing a fine particle dispersion of the present invention is not particularly limited, but the dispersion is obtained by bringing a metal gas into contact with a low vapor pressure liquid including 11 or more carbon atoms of the carboxylic acid. It is preferable from the point of being difficult to evaporate and forming a low vapor pressure liquid. The upper limit of the number of carbon atoms is preferably 17 or less in the case of saturated fatty acids from the viewpoint of solubility in a low vapor pressure liquid, dissolution stability, and the like. In the case of an unsaturated fatty acid, a carbon number of 25 or less is preferable from the same point, and 20 or less is particularly preferable.

  In the present invention, the fatty acid is dissolved in the low vapor pressure liquid. The concentration of the fatty acid is not particularly limited and can be appropriately adjusted. However, the fatty acid is 0.3 parts per 100 parts by mass of the low vapor pressure liquid. -50 mass parts is preferable, 1-20 mass parts is more preferable, and 3-10 mass parts is especially preferable. If the amount of fatty acid is too small, the dispersibility may be insufficient and may not be dispersed well. On the other hand, if the amount is too large, the viscosity of the dispersion becomes too high, and a “new low vapor pressure liquid film” can be formed by rotating the rotating drum. It may be difficult.

  According to the method for producing a fine particle dispersion of the present invention, a metal gas is vapor-deposited at the liquid interface and taken into the liquid to produce fine particles having a volume distribution median diameter (D50) of 100 nm or less. The fatty acid is considered to be directly involved in incorporation into the liquid, generation of fine particles in the liquid, control of the volume distribution median diameter (D50) of the fine particles, suppression of association between the fine particles, and the like. Therefore, since such roles and effects are very special, knowledge and techniques such as surfactants, additives, and dispersants used for improving dispersibility of general fine particles are hardly useful. That is, a compound used for dispersion known in other methods for producing fine particle dispersions cannot be simply used for the present invention. Further, it is not possible to simply convert a known dispersant to the present invention.

  Further, the fact that the fine particles are magnetic powder (ferromagnetic powder) means that the fine particles are large enough to have crystallinity, and the technique for dispersing such crystalline particles or fine particles so large is the present invention. However, this technique cannot be applied to a technology that can disperse into extremely small particles.

  When the method for producing a fine particle dispersion of the present invention is used, a dispersion dispersed with a volume distribution median diameter (D50) of 100 nm or less can be produced stably with excellent dispersibility. Moreover, it can disperse | distribute stably even if it is 10 nm or less, Furthermore, it can disperse | distribute also at 2 nm or less. Therefore, the volume distribution median diameter (D50) of the fine particles in the fine particle dispersion obtained by using the production method of the present invention is usually 1 to 100 nm, preferably 2 to 50 nm, more preferably 3 to 20 nm, particularly preferably. It is 4 to 15 nm, more preferably 5 to 10 nm. The smaller the volume distribution median diameter (D50), the better the effect of the present invention is achieved.

  In the present invention, the “volume distribution median diameter (D50)” is a scanning electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and a scanning transmission electron microscope (hereinafter “STEM”). A special bright-field STEM sample stand is attached, a 200,000 times magnification STEM photograph is taken, and the software is loaded into the following software, and several hundred to 2,000 particles are arbitrarily selected on the photograph. Each diameter was measured and determined as a 50% cumulative particle size by volume from a volume-based distribution.

  A measurement sample to be subjected to STEM was prepared by appropriately diluting a fine particle dispersion with toluene and dropping it onto a collodion film-attached mesh. Moreover, when obtaining the volume-based particle size distribution and volume distribution median diameter (D50) from the STEM photograph, image analysis type particle size distribution measurement software “Mac-View Ver. 4” manufactured by Mountec Co., Ltd. was used.

  The shape of the metal fine particles is not particularly limited, and may be any shape such as a spherical shape, a rod shape, a plate shape, and an indefinite shape. Further, the crystal structure of the fine particles is not particularly limited, but it is preferable that the fine particles are non-crystalline because the transparency of the dispersion and the dispersion described later is increased. Therefore, the production method of the present invention is suitable for forming amorphous fine particles.

  The concentration of the fine particles in the fine particle dispersion produced by the production method of the present invention is not particularly limited, but is preferably 1 to 90 parts by mass, more preferably 10 to 80 parts by mass with respect to 100 parts by mass of the fine particle dispersion. 20-70 mass parts is especially preferable. By using the present invention, a high-concentration fine particle dispersion can be obtained.

  The method for producing a fine particle dispersion of the present invention will be described in more detail with reference to the production apparatus shown in FIG. However, FIG. 1 is an example of a specific apparatus used in the present invention, and the present invention is not limited to the apparatus using the apparatus shown in FIG.

  In FIG. 1, the chamber (1) has a drum shape rotating around the fixed shaft (2), and the inside of the chamber (1) is evacuated to high vacuum through the fixed shaft (2). The chamber (1) contains a low vapor pressure liquid (3) in which fatty acids are dissolved, and the low vapor in which fatty acids are dissolved on the inner wall of the chamber (1) by the rotation of the drum-shaped chamber (1). A film (4) of pressurized liquid (3) is formed. A container (6) for holding the metal (5) is fixed inside the chamber (1). The metal (5) is heated to a predetermined temperature, for example, by passing an electric current through a resistance wire, and is released into the chamber (1) as a gas.

  The entire outer wall of the chamber (1) is cooled by the water flow (8). The atoms (9) released from the heated “metals (5)” into the vacuum are taken from the surface of the film (4) of the low vapor pressure liquid (3) in which the fatty acid is dissolved, and the fine particles (10). Is formed. Next, the low vapor pressure liquid (3) in which such fine particles (10) are dispersed is transported into the low vapor pressure liquid (3) at the bottom of the chamber (1) as the chamber (1) rotates, At the same time, a new “low vapor pressure liquid (3) membrane (4)” is fed to the top of the chamber (1).

  By continuing this process, the low vapor pressure liquid (3) at the bottom of the chamber (1) becomes a dispersion in which the metals (5) are dispersed at a high concentration.

  In the present invention, a fine particle dispersion is produced by directly incorporating a metal gas, an alloy gas, or a metal compound gas into a low vapor pressure liquid in which a fatty acid is dissolved. The present invention is not limited to the following actions and principles, but is considered as follows. That is, a metal gas, an alloy gas, or a metal compound gas is directly taken into a low vapor pressure liquid without agglomerating in the gas phase, causing aggregation in the low vapor pressure liquid, and a certain volume distribution median diameter ( It is considered that the aggregated particles are surrounded by fatty acids and stabilized as nano-particles at the time of having D50). At that time, it is considered that the fatty acid wraps the aggregated particles more quickly, suppresses the association with each other more strongly, and stabilizes more as nanoparticulates.

  The fine particle dispersion obtained by using the production method of the present invention uses the low vapor pressure liquid as a dispersion medium, but if the low vapor pressure liquid is used as a dispersion medium, the subsequent use If it is inappropriate for the above, it is preferable to prepare a “metal fine particle dispersion” by substituting the low vapor pressure liquid in the “metal fine particle dispersion” with another dispersion medium. That is, the low vapor pressure liquid is preferably one that is suitable from the viewpoint of dispersibility, but is preferably replaced with “another dispersion medium” that is suitable for the application in which the fine particles are used.

  The “other dispersion medium” is not particularly limited, and can be selected according to the use of the dispersion. Specific examples include aliphatic hydrocarbons such as normal hexane, cyclohexane, normal pentane, normal heptane, octane, decane, dodecane, tetradecane and hexadecane; aromatic hydrocarbons such as toluene and xylene; diethyl ether and diphenyl ether Ethers such as propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, dipropylene glycol monoethyl ether, etc .; glycol-based dispersion media; methanol, ethanol, propanol, butanol, hexanol, heptanol, octanol, decanol, cyclohexanol , Monohydric alcohols such as 2-ethyl-1-hexanol; ethylene glycol, diethylene glycol, 1,2-propanediol, dipropylene Divalent alcohols such as glycol, 1,4-butanediol, 2,3-butanediol, pentanediol, hexanediol, and octanediol; ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, acetylacetone, and cyclohexanone; ethyl acetate Esters such as 2-dimethylaminoethanol, 2-diethylaminoethanol, 2-dimethylaminoisopropanol, 3-diethylamino-1-propanol, 2-dimethylamino-2-propanol, 2-methylaminoethanol, 4-dimethylamino- Examples include amino group-containing alcohols such as 1-butanol. These may be used alone or in combination of two or more.

  As a method of substituting the low vapor pressure liquid with another dispersion medium, a known solvent replacement / dispersion medium replacement method is used. The fine particles obtained in the present invention can maintain a stable dispersion state even when the dispersion medium is replaced, during dispersion medium replacement, and during subsequent storage of the dispersion.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples unless it exceeds the gist.

Example 1
Using 380 g of Lion diffusion pump oil (A) (manufactured by Lion Corporation) as a low vapor pressure liquid, 20 g of 10-undecenoic acid (CH ₂ ═CH (CH ₂ ) ₈ COOH) was added as a fatty acid and stirred. Lion diffusion pump oil (A) is an alkylnaphthalene having an alkyl group having 12 to 16 carbon atoms. 10-Undecenoic acid is an unsaturated fatty acid having 11 carbon atoms.

A dispersion was produced using the apparatus shown in FIG. 20 g of silver (Ag) grains (manufactured by Tokuru Honten Co., Ltd .: purity 99.99%) was put in the container (6), and the liquid was put in the rotating drum type chamber (1). By suctioning with a vacuum pump, the pressure in the chamber (1) reached 10 ⁻³ Pa. Next, the chamber (1) is rotated while being cooled with the water flow (7), and an electric current is supplied to the heater provided in the lower part of the container (6), and the current value is increased until the silver (Ag) is dissolved and evaporated. It was.

  The silver (Ag) grains are dissolved, and the silver (Ag) gas comes into contact with the dispersion medium surface (the surface of the film (4) of the low vapor pressure liquid (3) in which 10-undecenoic acid is dissolved). A silver (Ag) fine particle dispersion was formed by incorporation into undecenoic acid.

  From the STEM photograph shown in FIG. 2 and the particle size distribution shown in FIG. 3, it was confirmed that particles of about 2 to 9 nm were dispersed without agglomeration. The volume distribution median diameter (D50) was 5.4 nm.

Example 2
In Example 1, as a fatty acid, in place of 10-undecenoic acid, except for using oleic acid _{(C 8 H 17 CH = CH} (CH 2) 7 COOH (cis)) is carried out in the same manner as in Example 1 It was. Oleic acid is an unsaturated fatty acid having 17 carbon atoms.

  From the STEM photograph shown in FIG. 4 and the particle size distribution shown in FIG. 5, it was confirmed that particles of about 3 to 10 nm were dispersed without agglomeration. The volume distribution median diameter (D50) was 5.2 nm.

  “Lion diffusion pump oil (A) as a low vapor pressure liquid” which is a dispersion medium of the obtained “silver (Ag) fine particle dispersion” is substituted with toluene as a dispersion medium according to a conventional method, and silver (Ag) A fine particle dispersion was obtained. By STEM observation, it was confirmed that particles of about 2 to 15 nm were dispersed without aggregation. The volume distribution median diameter (D50) was also about 5.2 nm, and it was also found that when fatty acid was used, the dispersibility did not deteriorate even when the dispersion medium was replaced, and the dispersion maintenance was excellent. This fine particle dispersion can be applied to various uses because toluene, which is a general-purpose solvent, is a dispersion medium.

Example 3
In Example 1, it replaced with 10-undecenoic acid as a fatty acid, and performed by the method similar to Example 1 except having used erucic acid. Erucic acid is an unsaturated fatty acid having 22 carbon atoms.

  From the STEM photograph shown in FIG. 6 and the particle size distribution shown in FIG. 7, it was confirmed that particles of about 1 to 10 nm were dispersed without agglomeration. The volume distribution median diameter (D50) was 5.9 nm.

Comparative Example 1
In Example 1, it replaced with 10-undecenoic acid and performed by the method similar to Example 1 except having used succinimide polyamine.

  However, STEM observation confirmed that the particles were agglomerated with each other. Further, it was observed visually that the fine particles had settled and accumulated, and a good dispersion could not be obtained.

Comparative Example 2
In Example 1, it replaced with 10-undecenoic acid and performed by the method similar to Example 1 except having used Disperbyk-102 (made by a Big Chemie company). Disperbyk-102 is a copolymer having acidic groups.

  However, STEM observation confirmed that the particles were agglomerated with each other. Further, it was observed visually that the fine particles had settled and accumulated, and a good dispersion could not be obtained.

  As is clear from the above results, in Examples 1 to 3 of the present invention, since fatty acids were used, association between fine particles was suppressed, and a fine particle dispersion having good dispersibility and dispersion stability was obtained. I was able to.

  On the other hand, those using no fatty acid (Comparative Example 1 and Comparative Example 2) were all poor in dispersibility and dispersion stability as compared with Examples 1 to 3.

  Dispersions and dispersions obtained by using the method for producing a fine particle dispersion of the present invention include IC substrates, wiring of semiconductor elements, interlayer connection of semiconductor modules, formation of transparent conductive films, and between metal and nonmetal. It is widely used for bonding, color filters using the colloidal color of liquid, and the like.

It is a schematic sectional drawing of an example of the apparatus used for the manufacturing method of the fine particle dispersion of this invention. It is a STEM photograph of the fine particles in the silver (Ag) fine particle dispersion produced in Example 1 using 10-undecenoic acid as a fatty acid (magnification, 200,000 times). 3 is a volume-based particle size distribution of fine particles in a silver (Ag) fine particle dispersion produced in Example 1 using 10-undecenoic acid as a fatty acid. It is a STEM photograph of the fine particles in the silver (Ag) fine particle dispersion produced in Example 2 using oleic acid as a fatty acid (magnification, 200,000 times). 3 is a volume-based particle size distribution of fine particles in a silver (Ag) fine particle dispersion produced in Example 2 using oleic acid as a fatty acid. It is a STEM photograph of the fine particles in the silver (Ag) fine particle dispersion produced in Example 3 using erucic acid as a fatty acid (magnification, 200,000 times). FIG. 3 is a volume-based particle size distribution of fine particles in a silver (Ag) fine particle dispersion produced in Example 3 using erucic acid as a fatty acid. FIG.

Explanation of symbols

1 Chamber 2 Fixed shaft 3 Low vapor pressure liquid in which fatty acid is dissolved 4 Low vapor pressure liquid film in which fatty acid is dissolved 5 Metal, alloy or metal compound (metals)
6 Container 7 Water flow 8 Direction of rotation 9 Atom or molecule 10 Fine particles of “metal, alloy or metal compound” (fine particles of metals)

Claims (5)

  By bringing a metal, alloy or metal compound gas into contact with a low vapor pressure liquid, a dispersion in which fine particles of the metal, alloy or metal compound are dispersed in the low vapor pressure liquid with a volume distribution median diameter (D50) of 100 nm or less is obtained. A method for producing a fine particle dispersion, wherein a fatty acid is dissolved in the low vapor pressure liquid.   The method for producing a fine particle dispersion according to claim 1, wherein the fatty acid has 11 or more carbon atoms. The fine particle dispersion according to claim 1 or 2, wherein the metal gas or the metal compound gas is contacted with the low vapor pressure liquid under a pressure in the range of 10 ^-4 Pa to 10 ^-1 Pa. Method.   A fine particle dispersion produced by using the method for producing a fine particle dispersion according to any one of claims 1 to 3.   5. A fine particle dispersion of metal, alloy or metal compound, wherein the low vapor pressure liquid in the fine particle dispersion according to claim 4 is replaced with another dispersion medium.