JP2009007593A - Fine particle dispersion and method for producing fine particle dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine particle dispersion which is excellent in dispersibility and storage stability. <P>SOLUTION: Specifically disclosed is a fine particle dispersion wherein fine particles composed of one or more of metals, alloys and metal compounds and having an average primary particle diameter of 1 to 150 nm are dispersed in a mixed solvent (S1) containing 50 to 95% by volume of an organic solvent (A) having an amide group and ≥5% by volume of a low-boiling point organic solvent (B) having a boiling point at normal pressure of 20 to 100°C, or a mixed solvent (S2) containing 50 to 94 by volume of an organic solvent (A) having an amide group, ≥5% by volume of a low-boiling point organic solvent (B) having a boiling point at normal pressure of 20 to 100°C and ≥1% by volume of an organic solvent (C) having a boiling point at normal pressure of >100°C and composed of an alcohol having one or more hydroxy groups in a molecule and/or a polyhydric alcohol. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fine particle dispersion in which fine particles composed of one or more of metals, alloys, and metal compounds, which are excellent in dispersibility, storage stability, and the like, are dispersed in a specific mixed solvent, and a method for producing the same.

It is known that nano-sized metal particles (particle size of 1 μm or less) have various unique characteristics not found in bulk materials. Various engineering applications that take advantage of this property are now highly expected in fields such as electronics, biotechnology, and energy.
Among them, nano-sized metal fine particles made of industrial general-purpose metals such as copper, nickel, cobalt, iron, zinc, tin, silver, and their alloys are used to form mounting parts such as conductive circuits, bumps, vias, and pads. It is highly expected as a catalyst material for high-density magnetic storage media, magnetic elements for antennas, gas improvement filters and fuel cell electrodes.

As methods for producing such nano-sized metal fine particles, two types of production methods, a gas phase synthesis method and a liquid phase synthesis method, are widely known. Here, the gas phase synthesis method is a method of forming solid metal fine particles from metal vapor introduced into the gas phase, while the liquid phase synthesis method is to reduce metal ions dispersed in a solution. This is a method of depositing metal fine particles.
In addition, in the liquid phase synthesis method, there are generally known a method using a reducing agent for reducing the metal ions and a method of electrochemical reduction on the cathode electrode.

  In recent years, attention has been paid to a technique for forming a wiring by printing a wiring pattern by an ink jet printer using an ink containing metal fine particles and baking it. However, when ink containing metal fine particles is used as ink for an ink jet printer, it is important to maintain dispersibility in the ink for a long period of time. For this reason, a method for producing fine metal particles that maintains dispersibility in ink for a long period of time has been proposed.

Further, the following patent documents are disclosed as a method for obtaining a metal thin film or a metal fine wire by drying a metal fine particle dispersion and then baking it.
As a method for obtaining copper fine particles, palladium ions for nucleation are added, and polyethyleneimine is added as a dispersant to form copper fine particles having a particle size of 50 nm or less containing palladium in a polyethylene glycol or ethylene glycol solution. Then, in order to perform pattern printing on the substrate using this copper fine particle dispersion, heat treatment is performed at 250 ° C. for 3 hours in a 4% H ₂ —N ₂ gas stream to form a fine copper conductive film. The formation is described (Patent Document 1).

After an ink-jet ink containing metal oxide fine particles having a primary particle size of 100 nm or less is applied on a substrate by an ink-jet method, a heat treatment is performed at 350 ° C./1 hour in a hydrogen gas atmosphere to obtain cuprous oxide. It is disclosed that a metal wiring pattern is obtained by performing reduction (Patent Document 2).
Metal nanoparticles with an organometallic compound attached as a dispersant around the metal are applied onto a substrate (glass) by spin coating, dried at 100 ° C., and then fired at 250 ° C. to produce a silver thin film. (Patent Document 3).
Further, copper acetate having an average particle size of 500 nm suspended in diethylene glycol is concentrated to a concentration of 30% by weight, and further subjected to ultrasonic treatment to obtain a conductive ink, followed by a slide. It is described that it was coated on glass and heated at 350 ° C. for 1 hour in a reducing atmosphere to obtain a copper thin film (Patent Document 4).

JP 2005-330552 A JP 2004-277627 A JP 2005-81501 A JP 2004-323568 A

Form metal fine particles coated with an organic protective film by using a reducing agent in an aqueous solution in which the organic protective film is dissolved in the above-mentioned metal ions, and add and agglomeration accelerator to this to separate and recover the particle components. In addition, in the method for producing a metal fine particle dispersion, which is washed and redispersed in an alcohol solvent having one or more hydroxyl groups in the molecule, there is still room for improvement in the dispersibility of the metal fine particles in the solvent. .
Moreover, in the conventional manufacturing methods in Patent Documents 1 and 2 described above, Patent Document 3 and Patent Document 4, a conductive metal cannot be obtained unless heat treatment is performed at a high temperature close to 250 to 300 ° C. There is also a problem that a reducing agent such as hydrogen gas must be used during the heat treatment.
Furthermore, the fine particle dispersion in which metal fine particles are dispersed in an alcohol solvent has still been insufficient in adhesion of the fired film to the substrate even though a conductive fired film can be obtained on the substrate by heat treatment.

In view of the above prior art, the present inventors have mixed organic solvent containing 50% to 95% by volume of an organic solvent having an amide group and 5% by volume or more of a low boiling point organic solvent having a boiling point of 20 to 100 ° C. at normal pressure. ,
Alternatively, the organic solvent having an amide group is 50 to 94% by volume, the low boiling point organic solvent having a boiling point of 20 to 100 ° C. at a normal pressure of 5% by volume or more, and one or more in a molecule having a boiling point of 100 ° C. When fine particles such as metal are dispersed in a mixed solvent containing 1% by volume or more of an organic solvent composed of an alcohol having two or more hydroxyl groups and / or a polyhydric alcohol, dispersibility and storage stability are remarkably improved. The inventors have found that a fine particle dispersion excellent in substrate adhesion can be obtained when producing a thin film or a fine metal wire, and have completed the present invention.

That is, the present invention provides: (1) Fine particles having an average primary particle size of 1 to 150 nm, which is composed of one or more of metals, alloys, and metal compounds,
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
The fine particle dispersion is characterized by being dispersed in (hereinafter, sometimes referred to as a first embodiment).

In the “fine particle dispersion” which is the first aspect, the following aspects (2) to (9) may be further provided.
(2) The organic solvent (A) is N-methylacetamide, N-methylformamide, N-methylpropanamide, formamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N, N -One or more selected from dimethylformamide, 1-methyl-2-pyrrolidone, hexamethylphosphoric triamide, 2-pyrrolidinone, ε-caprolactam, and acetamide.
(3) The organic solvent (B) is represented by the general formula R ¹ —O—R ² (wherein R ¹ and R ² are each independently an alkyl group and have 1 to 4 carbon atoms). Alcohol (B2) represented by ether compound (B1), general formula R ³ —OH (R ³ is an alkyl group having 1 to 4 carbon atoms), R ⁴ —C (═O) A ketone compound (B3) represented by —R ⁵ (R ⁴ and R ⁵ each independently represents an alkyl group and has 1 to 2 carbon atoms), and a general formula R ⁶ — (N—R ⁷ ) In an amine compound (B4) represented by -R ⁸ (R ⁶ , R ⁷ , R ⁸ are each independently an alkyl group or hydrogen, and the number of carbon atoms is 0 to 2). It is 1 type, or 2 or more types selected from.

(4) The ether compound (B1) is selected from among diethyl ether, methyl propyl ether, dipropyl ether, diisopropyl ether, methyl-t-butyl ether, t-amyl methyl ether, divinyl ether, ethyl vinyl ether, and allyl ether. One or more selected.
(5) The alcohol (B2) is one or more selected from methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, and 2-methyl 2-propanol.
(6) The ketone compound (B3) is one or more selected from acetone, methyl ethyl ketone, and diethyl ketone.
(7) The amine compound (B4) is triethylamine and / or diethylamine.

(8) The organic solvent (C) is ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol. -L, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, glycerol, 1,1,1-tris Hydroxymethylethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butanetriol, glycerol , Threitol, erythritol, pentaerythritol, pentitol, and hexitol.
(9) The metal is selected from copper, silver, gold, nickel, cobalt, iron, zinc, tin, aluminum, bismuth, platinum, rhodium, palladium, ruthenium, rhodium, manganese, chromium, vanadium, and titanium. One or two or more of the above, an alloy in which the alloy is composed of two or more of the metals, and the metal compound are oxides of the metal and the alloy.

Further, the present invention provides (10) fine particles having an average primary particle diameter of 1 to 150 nm, comprising one or more of metals, alloys, and metal compounds,
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
A method of producing a fine particle dispersion dispersed in
(I) In an aqueous solution containing a water-soluble polymer capable of forming a protective film, fine particles having an average particle diameter of primary particles of 1 to 150 nm composed of one or more of the metals, alloys, and metal compounds. Or a step of forming a dispersion state in which the metal ions are reduced by electrolytic reduction or electroless reduction using a reducing agent in an organic solvent and coated with a protective film formed from the water-soluble polymer, and then (ii) ) A method for producing a fine particle dispersion, comprising a step of adding an aggregation accelerator in the aqueous solution or an organic solvent to aggregate and precipitate the fine particles and recovering the fine particles (hereinafter referred to as a method for producing a fine particle dispersion). , Sometimes referred to as a second aspect).

In the “method for producing a fine particle dispersion” as the second aspect, the following aspects (11) to (15) may be further provided.
(11) The organic solvent (A) is N-methylacetamide, N-methylformamide, N-methylpropanamide, formamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N, N -One or more selected from dimethylformamide, 1-methyl-2-pyrrolidone, hexamethylphosphoric triamide, 2-pyrrolidinone, ε-caprolactam, and acetamide.
(12) The organic solvent (B) is represented by the general formula R ¹ —O—R ² (wherein R ¹ and R ² are each independently an alkyl group and have 1 to 4 carbon atoms). Alcohol (B2) represented by ether compound (B1), general formula R ³ —OH (R ³ is an alkyl group having 1 to 4 carbon atoms), R ⁴ —C (═O) A ketone compound (B3) represented by —R ⁵ (R ⁴ and R ⁵ each independently represents an alkyl group and has 1 to 2 carbon atoms), and a general formula R ⁶ — (N—R ⁷ ) In an amine compound (B4) represented by -R ⁸ (R ⁶ , R ⁷ , R ⁸ are each independently an alkyl group or hydrogen, and the number of carbon atoms is 0 to 2). It is 1 type, or 2 or more types selected from.

(13) The organic solvent (C) is ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol. -L, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, glycerol, 1,1,1-tris Hydroxymethylethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butanetriol, glycerol , Threitol, erythritol, pentaerythritol, pentitol, and hexitol.

(14) The water-soluble polymer is one or more selected from polyvinylpyrrolidone, polyethyleneimine, polyacrylic acid, carboxymethylcellulose, polyacrylamide, polyvinyl alcohol, polyethylene oxide, starch, and gelatin. .
(15) The aggregation accelerator is ethylene chlorohydrin, allyl chloride, ethyl chloride, benzyl chloride, methyl chloride, methylene chloride, chloronaphthalene, chloropropylene, chlorobenzol, chloroform, chloroprene, acetylene tetrachloride, ethane tetrachloride, tetra One or more selected from carbon chloride, dichloroethane, dichloroethylene, dichlorobenzol, trichloroethylene, trichloromethane, bromobenzole, bromoform, and hexachloroethane.

Furthermore, the present invention provides (16) fine particles having an average primary particle diameter of 1 to 150 nm, comprising one or more of metals, alloys and metal compounds.
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
A method of producing a fine particle dispersion dispersed in
The present invention provides a method for producing a fine particle dispersion characterized by including at least the following steps 1 to 3 (hereinafter sometimes referred to as a third embodiment).

(A) Step 1
Metal ions are reduced by electrolytic reduction or electroless reduction using a reducing agent in an aqueous solution in which at least one metal ion and a water-soluble polymer capable of forming a protective film are dissolved. An aqueous solution in which fine particles (P1) having an average particle diameter of 1 to 150 nm of primary particles made of one or more of metals, alloys, and metal compounds coated with a protective coating formed from 1 is formed. To
(B) Step 2
An agglomeration promoter is added to the aqueous solution in which the fine particles (P1) are dispersed and stirred to agglomerate or precipitate fine particles comprising one or more of the metal, alloy, and metal compound, and (i) The aggregate or precipitate is separated and collected by washing with a cleaning solvent, or (ii) the aggregate or precipitate is washed with a washing solvent after separation and collection, and one or more of metals, alloys, and metal compounds or Obtaining fine particles (P2) composed of two or more kinds,
(C) Step 3
The fine particles (P2) made of one or more of the metals, alloys, and metal compounds are redispersed in the mixed solvent (S1) or the mixed solvent (S2), and the fine particles (P2) are mixed with the mixed solvent (S1). ) Or a fine particle dispersion dispersed in the mixed solvent (S2).
In the “method for producing a fine particle dispersion” as the third aspect, the following aspects (17) to (26) may be further provided.

(17) The metal ions in Step 1 are copper, silver, gold, nickel, cobalt, iron, zinc, tin, aluminum, bismuth, platinum, rhodium, palladium, ruthenium, rhodium, manganese, chromium, vanadium, and titanium. It is a metal ion of one or more metals selected from the inside.
(18) The water-soluble polymer in the step 1 is one or two selected from polyvinyl pyrrolidone, polyethyleneimine, polyacrylic acid, carboxymethyl cellulose, polyacrylamide, polyvinyl alcohol, polyethylene oxide, starch, and gelatin. More than a seed.
(19) The reducing agent in Step 1 is one or more selected from sodium borohydride, hydrazine, dimethylaminoborane, and trimethylaminoborane.
(20) The aggregation accelerator in the step 2 is ethylene chlorohydrin, allyl chloride, ethyl chloride, benzyl chloride, methyl chloride, methylene chloride, chloronaphthalene, chloropropylene, chlorobenzole, chloroform, chloroprene, acetylene tetrachloride, tetra One or more selected from ethane chloride, carbon tetrachloride, dichloroethane, dichloroethylene, dichlorobenzole, trichloroethylene, trichloromethane, brombenzol, bromoform, and hexachloroethane.
(21) The cleaning solvent used in Step 2 is water and / or a C 1-6 alcohol or polyhydric alcohol having at least one hydroxyl group in the molecule.

(22) The organic solvent (A) used in Step 3 is N-methylacetamide, N-methylformamide, N-methylpropanamide, formamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolide One or more selected from non, N, N-dimethylformamide, 1-methyl-2-pyrrolidone, hexamethylphosphoric triamide, 2-pyrrolidinone, ε-caprolactam, and acetamide.
(23) The organic solvent (B) used in the step 3 is represented by the general formula R ¹ —O—R ² (R ¹ and R ² are each independently an alkyl group and have 1 to 4 carbon atoms. ) Represented by the ether compound (B1), the general formula R ³ —OH (R ³ is an alkyl group and has 1 to 4 carbon atoms), and the alcohol (B 2) and the general formula R A ketone compound (B3) represented by ^4- C (═O) —R ⁵ (wherein R ⁴ and R ⁵ are each independently an alkyl group having 1 to 2 carbon atoms), and a general formula R ^6- (N—R ⁷ ) —R ⁸ (R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group or hydrogen, and the number of carbon atoms is 0 to 2). It is 1 type, or 2 or more types selected from a compound (B4).

(24) The organic solvent (C) used in Step 3 is ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, glycerol, 1, 1,1-trishydroxymethylethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butane One or more selected from triol, glycerol, threitol, erythritol, pentaerythritol, pentitol, and hexitol.
(25) When redispersing the fine particles (P2) of one or more of the metals, alloys, and metal compounds in the mixed solvent (S1) or the mixed solvent (S2) in the step 3, ultrasonic waves It is characterized by irradiating.
(26) The metal is selected from copper, silver, gold, nickel, cobalt, iron, zinc, tin, aluminum, bismuth, platinum, rhodium, palladium, ruthenium, rhodium, manganese, chromium, vanadium, and titanium. One or two or more of the above, an alloy in which the alloy is composed of two or more of the metals, and the metal compound are oxides of the metal and the alloy.

In the fine particle dispersion of the present invention, since the mixed solvent (S1) or the mixed solvent (S2) is used as a dispersion for dispersing fine particles, the dispersibility, dispersion efficiency, storage stability, aggregation redispersion of the fine particles are used. Excellent in properties and sinterability. When the fine particle dispersion of the present invention is used in an ink composition for ink jet, it is excellent in dispersibility and storage stability, so that clogging of fine metal particles in the ink jet head can be prevented.
The fine particles dispersed in the dispersion are produced by a liquid phase reduction reaction in the presence of a water soluble polymer capable of forming a protective film, and the water soluble polymer used in the liquid phase reduction reaction is an aggregation accelerator. Therefore, fine particles having a low content of impurities such as a water-soluble polymer can be dispersed in the dispersion. As a result, when the obtained fine particle dispersion is placed on a substrate by ink jet and baked, a metal thin film, a fine metal wire or the like having excellent substrate adhesion and conductivity can be obtained.

Hereinafter, the organic solvent (A) having an amide group is referred to as “organic solvent (A)”, the low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure is referred to as “organic solvent (B)”, The organic solvent (C) consisting of an alcohol and / or a polyhydric alcohol whose boiling point at normal pressure exceeds 100 ° C. and having one or more hydroxyl groups in the molecule is described as “organic solvent (C)”. There is.
[1] About the “fine particle dispersion” as the first aspect The “fine particle dispersion” according to the first aspect of the present invention is a primary particle composed of one or more of metals, alloys, and metal compounds. Fine particles having an average particle size of 1 to 150 nm
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
It is characterized in that it is distributed.

(1) Metal, Alloy, and Metal Compound The “metal, alloy, and metal compound” that can be used in the present invention is not particularly limited, and the metal is copper, silver, gold, nickel, cobalt, iron. One or more metals selected from zinc, tin, aluminum, bismuth, platinum, rhodium, palladium, ruthenium, rhodium, manganese, chromium, vanadium, and titanium, and from two or more of these metals It may be appropriately selected according to the purpose and application from the alloy to be formed and one or more metal compounds of these metals.
The metal compound includes oxides of metals and alloys. When the fine particles of the present invention are produced, oxides of metals and alloys are often contained. In particular, transition metal particles such as copper contain few oxides. The level of oxidation varies depending on the atmosphere, temperature, and holding time during the generation and storage of the fine particles. Only the outermost surface of the fine particles is oxidized thinly and the inside remains metal, or the fine particles are completely oxidized. There may be. The “metal compound” as used in the present invention contains all such particles in various oxidation states.
Among the above metals, one or more metals selected from metals such as Cu, Ag, and Au, or an alloy composed of two or more of these metals is preferable.

(2) Mixed solvent The “mixed solvent” in the present invention refers to (i) 50 to 95% by volume of the organic solvent (A) and 5% by volume or more of the organic solvent (B) (S1) or (ii) It is a mixed solvent (S2) containing 50 to 94% by volume of the organic solvent (A), 5% by volume or more of the organic solvent (B), and 1% by volume or more of the organic solvent (C). In the mixed solvent (S1), the organic solvent (A) improves the dispersibility and storage stability in the mixed solvent, and further adheres to the substrate when baked on the substrate in a state containing fine particles such as the metal. Has the effect of improving the properties.
The organic solvent (B) is considered to have an action of reducing the interaction between solvent molecules in the mixed solvent and improving the affinity of the dispersed particles to the solvent. Such an effect is generally expected in a solvent having a low boiling point. Particularly, an organic solvent having a boiling point of 100 ° C. or less at normal temperature is preferable because an effect of reducing the interaction between effective solvent molecules is obtained. Among the organic solvents (B), ether compounds (B1) are particularly preferable because they have a large effect of reducing the interaction between the solvent molecules.
In addition, when the organic solvent (B) is used, the stirring time can be remarkably shortened, for example, about 1/2 when preparing the fine particle dispersion by irradiation with ultrasonic waves or the like. Further, when the organic solvent (B) is present in the mixed solvent, it can be easily redispersed even if the particles are in an aggregated state.

The organic solvent (A) and the organic solvent (B) in the mixed solvent (S2) are the same as described in the mixed solvent (S1) except that the concentration of the organic solvent (A) is 50 to 94% by volume. is there.
The organic solvent (C) improves the dispersibility in the mixed solvent, and has the following effects in particular. That is, the mixed solvent containing the organic solvent (A) and the organic solvent (B) has excellent dispersibility by stirring, but there is a tendency that the fine particles are joined to each other over time, but the organic solvent (C). In the mixed solvent, it is possible to more effectively suppress such bonding and further stabilize the dispersion for a long period of time. Further, when the organic solvent (C) is present in the mixed solvent, the uniformity of the sintered film is improved when the fine particle dispersion is applied and sintered on the substrate, and a highly conductive fired film can be obtained. .
As described above, (i) the mixed solvent (S1) containing the organic solvent (A) and the organic solvent (B) at a certain ratio is easily dispersed by stirring such as ultrasonic waves and has excellent dispersibility. Therefore, even if the particles become agglomerated, they can be easily redispersed.
The mixed solvent (S2) containing the organic solvent (A), the organic solvent (B), and the organic solvent (C) in a certain ratio further improves dispersibility stability and sinterability. Such a mixed solvent (S1) and mixed solvent (S2) are mixed solvents excellent in dispersibility when forming a jet ink layer by an ink jet method.
In addition, the blending ratio of each solvent type in the mixed solvent (S1) and the mixed solvent (S2) is based on the volume ratio of each solvent before solvent mixing (hereinafter, the second mode and the third mode). The same in).

  The organic solvent (A) is a compound having an amide group (—CONH—), and preferably has a high relative dielectric constant. As an organic solvent (A), N-methylacetamide (191.3 at 32 ° C), N-methylformamide (182.4 at 20 ° C), N-methylpropanamide (172.2 at 25 ° C), formamide (111.0 at 20 ° C), N , N-dimethylacetamide (37.78 at 25 ° C), 1,3-dimethyl-2-imidazolidinone (37.6 at 25 ° C), N, N-dimethylformamide (36.7 at 25 ° C), 1-methyl-2-pyrrolidone (32.58 at 25 [deg.] C.), hexamethylphosphoric triamide (29.0 at 20 [deg.] C.), 2-pyrrolidinone, [epsilon] -caprolactam, acetamide and the like can be mentioned, and these can also be used in combination. The number in parentheses after the name of the compound having an amide group indicates the relative dielectric constant at the measurement temperature of each solvent. Among these, N-methylacetamide, N-methylformamide, formamide, acetamide and the like having a relative dielectric constant of 100 or more can be preferably used. In addition, when it is solid at normal temperature like N-methylacetamide (melting point: 26-28 degreeC), it can mix with another solvent and can be used as a liquid state at working temperature.

The organic solvent (B) is an organic compound having a boiling point in the range of 20 to 100 ° C. at normal pressure.
When the particle dispersion containing the organic solvent (B) is stored at room temperature when the boiling point at normal pressure is less than 20 ° C., the components of the organic solvent (B) easily volatilize and the solvent composition in the dispersion changes. There is a risk of it. Moreover, when the boiling point at the same normal temperature is 100 ° C. or lower, it can be expected that the effect of further reducing the mutual attractive force between the solvent molecules due to the addition of the solvent and further improving the dispersibility of the fine particles can be expected.
As the organic solvent (B), an ether compound represented by the general formula R ¹ —O—R ² (wherein R ¹ and R ² are each independently an alkyl group and has 1 to 4 carbon atoms). B1), the general formula ^R 3 -OH ^{(R 3} is an alkyl group, number of carbon atoms is 1-4.) alcohol represented by (B2), the general formula ^R 4 -C (= O) -R ⁵ (R ⁴ and R ⁵ are each independently an alkyl group and have 1 to 2 carbon atoms), and a ketone compound (B 3) represented by formula (I) and a general formula R ⁶ — (N—R ⁷ ) ^{-R 8 (R 6, R 7} , R 8 are each independently an alkyl group, or hydrogen, carbon atoms is 0-2.) amine compounds represented by (B4) can be exemplified.
Examples of the organic solvent (B) are shown below, but the number in parentheses after the compound name indicates the boiling point at normal pressure.

Examples of the ether compound (B1) include diethyl ether (35 ° C.), methyl propyl ether (31 ° C.), dipropyl ether (89 ° C.), diisopropyl ether (68 ° C.), methyl t-butyl ether (55.3 ° C.). ), T-amyl methyl ether (85 ° C.), divinyl ether (28.5 ° C.), ethyl vinyl ether (36 ° C.), allyl ether (94 ° C.) and the like.
Examples of the alcohol (B2) include methanol (64.7 ° C), ethanol (78.0 ° C), 1-propanol (97.15 ° C), 2-propanol (82.4 ° C), 2-butanol (100 ° C). ), 2-methyl 2-propanol (83 ° C.) and the like.
Examples of the ketone compound (B3) include acetone (56.5 ° C.), methyl ethyl ketone (79.5 ° C.), diethyl ketone (100 ° C.) and the like.
Examples of the amine compound (B4) include triethylamine (89.7 ° C.) and diethylamine (55.5 ° C.).

The organic solvent (C) is an organic compound composed of an alcohol and / or a polyhydric alcohol having a boiling point exceeding 100 ° C. and having one or two or more hydroxyl groups in the molecule. Both alcohols have boiling points exceeding 100 ° C. Further, alcohols having 5 or more carbon atoms and polyhydric alcohols having 2 or more carbon atoms are preferable, and those having a high relative dielectric constant, such as those having 10 or more, are liquid at room temperature.
Specific examples of the organic solvent (C) include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol. -L, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, glycerol, 1,1,1-tris Examples include hydroxymethylethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butanetriol and the like. .

In addition, sugar alcohols such as glycerol, threitol, erythritol, pentaerythritol, pentitol and hexitol can be used, and pentitol includes xylitol, ribitol, and arabitol. included. The hexitol includes mannitol, sorbitol, dulcitol and the like. In addition, glyceraldehyde, dioxyacetone, threose, erythrulose, erythrose, arabinose, ribose, ribulose, xylose, xylulose, lyxose, glucose, fructose, mannose, idose, sorbose, growth, talose, tagatose, galactose, allose Sugars such as altrose, lactose, xylose, arabinose, isomaltose, glucoheptose, heptose, maltotriose, lactulose, trehalose, etc. can also be used.
Among the above alcohols, polyhydric alcohols having two or more hydroxyl groups are more preferable, and ethylene glycol and glycerin are particularly preferable.

The organic solvent (A) needs to be contained in the mixed solvent (S1) in an amount of 50 to 95% by volume and in the mixed solvent (S2) in an amount of 50 to 94% by volume. When the organic solvent (A) is less than 50% by volume, the dispersibility and storage stability of the metal fine particles in the polar organic solvent may be insufficient. In order to contain 5% by volume or more of the organic solvent (B) in the mixed solvent (S1), the organic solvent (A) needs to be 95% by volume or less. In the mixed solvent (S2), the organic solvent (B ) In an amount of 5% by volume or more and the organic solvent (C) in an amount of 1% by volume or more, the organic solvent (A) needs to be 94% by volume or less. A preferable concentration of the organic solvent (A) in the mixed solvent (S1) and the mixed solvent (S2) is 60 to 90% by volume, particularly preferably 65 to 85% by volume.
The organic solvent (A) has an effect of improving the dispersibility and storage stability of the fine particles in the mixed solvent in the first to third aspects of the present invention, and the fine particle dispersion of the present invention is applied to the substrate. It also has the effect | action which improves the electroconductivity of the baking film obtained by baking after apply | coating to.
The organic solvent (B) needs to be contained in 5% by volume or more in the mixed solvent (S1) and the mixed solvent (S2). When the organic solvent (B) is less than 5% by volume, there is a possibility that the dispersion time is shortened by the physical stirring of the metal fine particles and the redispersibility is insufficient. The preferable organic solvent (B) concentration in the mixed solvent is 5 to 50% by volume.
The organic solvent (C) is desirably contained in an amount of 1% by volume or more in the mixed solvent (S2). When the organic solvent (C) is contained in the mixed solvent (S2) in an amount of 1% by volume or more, the dispersion stability is further improved by suppressing the aggregation of metal fine particles and the like even when stored for a long period of time. The denseness and conductivity of the fired film obtained when the fine particle dispersion is sintered are further improved.

It is presumed that a part of the organic solvent (C) exists in the mixed solvent (S2) so as to cover the surface of the fine particles and exerts the above action, so that a preferable concentration is in the mixed solvent (S2). Although it varies depending on the concentration of fine particles present, it is preferably 1 to 50% by volume, more preferably 10 to 30% by volume, and particularly preferably 15 to 25% by volume.
The mixed solvent (S1) may be composed of the organic solvent (A) and the organic solvent (B) within the scope of the present invention, and the mixed solvent (S1) includes other than the organic solvent (A) and the organic solvent (B). When the constituent components are blended, polar organic solvents such as tetrahydrofuran, diglyme, ethylene carbonate, propylene carbonate, sulfolane and dimethyl sulfoxide can be used.
The mixed solvent (S2) may be composed of the organic solvent (A), the organic solvent (B), and the organic solvent (C) within the scope of the present invention. When a component other than the organic solvent (B) and the organic solvent (C) is blended, polar organic solvents such as tetrahydrofuran, diglyme, ethylene carbonate, propylene carbonate, sulfolane, dimethyl sulfoxide and the like can be used.
In the mixed solvent used in the present invention, practically, the mixed solvent (S1) in which the concentration of the organic solvent (A) is about 50 to 90% by volume and the other components are the organic solvent (B), or other components. It is more preferable to use a mixed solvent (S2) in which the organic solvent (B) and the organic solvent (C) are used.

(3) Shapes of metals, alloys, and metal compounds The average particle size of the fine particles dispersed in the mixed solvent (S1) and mixed solvent (S2) is 1 to 2 in consideration of the intended use of a metal thin film, a thin metal wire, etc. 150 nm is desirable. Such fine particles can be formed by a liquid phase reduction reaction of metal ions as described in the second and third aspects described later, or a known reduction reaction. Moreover, since the mixed solvent (S1) and the mixed solvent (S2) of the present invention are excellent in fine particle dispersibility, the average secondary aggregate size of secondary aggregated particles composed of these fine particles is 500 nm or less, preferably 300 nm. It is easy to:
(4) When the fine particle dispersion which is the first aspect is placed on a substrate by ink jet, dried and then heated and fired, a metal thin film, a fine metal wire, etc. having excellent substrate adhesion and conductivity can be obtained. .

[2] About “Method for Producing Fine Particle Dispersion” as Second Aspect “The method for producing fine particle dispersion” according to the second aspect of the present invention is one or two of metals, alloys, and metal compounds. Fine particles comprising at least seeds and having an average primary particle diameter of 1 to 150 nm,
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
A method of producing a fine particle dispersion dispersed in
(I) In an aqueous solution containing a water-soluble polymer capable of forming a protective film, fine particles having an average particle diameter of primary particles of 1 to 150 nm composed of one or more of the metals, alloys, and metal compounds. Or a step of forming a dispersion state in which the metal ions are reduced by electrolytic reduction or electroless reduction using a reducing agent in an organic solvent and coated with a protective film formed from the water-soluble polymer, and then (ii) ) Including a step of collecting the fine particles by aggregation or precipitation by adding an aggregation accelerator into the aqueous solution or organic solvent.

The metal, alloy, and metal compound used in the second embodiment are the same as the metal, alloy, and metal compound described in the first embodiment.
Fine particles composed of one or more of metals, alloys and metal compounds reduce metal ions by liquid phase reduction in the aqueous solution or organic solvent in which a water-soluble polymer capable of forming a protective film is dissolved. Thus, it is formed as fine particles coated with an organic protective film made of a water-soluble polymer.
The liquid phase reduction can be carried out by reducing metal ions by electrolytic reduction or electroless reduction using a reducing agent, and these liquid phase reductions can be carried out using known methods.

The water-soluble polymer that can form the protective film is preferably an amine polymer such as polyvinylpyrrolidone or polyethyleneimine; a hydrocarbon polymer having a carboxylic acid group such as polyacrylic acid or carboxymethylcellulose; polyacrylamide Such as acrylamide; polyvinyl alcohol, polyethylene oxide, starch, and one or more selected from gelatin and gelatin.
Specific examples of the water-soluble polymer compounds exemplified above include polyvinylpyrrolidone (molecular weight: 1000 to 500,000), polyethyleneimine (molecular weight: 100 to 100,000), carboxymethylcellulose (carboxymethyl of hydroxyl group Na salt of alkali cellulose) Substitution degree: 0.4 or more, molecular weight: 1000 to 100,000, polyacrylamide (molecular weight: 100 to 6,000,000), polyvinyl alcohol (molecular weight: 1000 to 100,000), polyethylene glycol (molecular weight) : 100-50,000), polyethylene oxide (molecular weight: 50,000-900,000), gelatin (average molecular weight: 61,000-67,000), water-soluble starch and the like.

The number average molecular weight of each polymer compound is shown in the parentheses, but those having such molecular weight range are water-soluble and can be suitably used as the organic protective film of the present invention. In addition, these 2 or more types can also be mixed and used.
The amount of the water-soluble polymer compound added is the mass ratio ([(water-soluble) of metal, alloy, and metal compound present in the reduction reaction solution, or one or more of them (hereinafter sometimes referred to as metal). The functional polymer compound) / (metal etc.)] mass ratio) is preferably 0.01 to 30. If the addition ratio of the water-soluble polymer compound exceeds 30, the viscosity of the solution may increase, which may hinder particle purification after the reduction reaction. On the other hand, if it is less than 0.01, the particles may be coarsened or the particles may form a strong aggregate due to the crosslinking effect. A more preferable addition ratio is 0.5 to 10.

Preferred aggregation promoters used in the second embodiment are ethylene chlorohydrin, allyl chloride, ethyl chloride, benzyl chloride, methyl chloride, methylene chloride, chloronaphthalene, chloropropylene, chlorobenzole, chloroform, chloroprene, tetrachloride. One or more selected from acetylene, ethane tetrachloride, carbon tetrachloride, dichloroethane, dichloroethylene, dichlorobenzole, trichloroethylene, trichloromethane, bromobenzole, bromoform, hexachloroethane and the like.
The addition amount of such an aggregation promoter is ([aggregation promoter (sometimes referred to as metal mass)) consisting of one or more of metals, alloys, and metal compounds. mol)] / [mass equivalent metal (g)]) ratio of 0.01 to 10.0 is preferable, and 0.1 to 1.0 is more preferable.

In the second aspect, after the step of adding and aggregating and precipitating the fine particles by adding an aggregation accelerator or the like to the aqueous solution or the organic solvent, the collected fine particles are at least 1 in water and / or molecules, for example. By washing with the above alcohol solvent having a hydroxyl group, impurities adhering to the fine particles are removed. The fine particles from which impurities are thus removed can be dispersed in the mixed solvent (S1) or the mixed solvent (S2). In this case, the solvent species used in the mixed solvent (S1) and the mixed solvent (S2) and the mixing ratio thereof are the same as those described in the first embodiment.
In the mixed solvent (S1) or the mixed solvent (S2) thus obtained, fine particles having an average primary particle diameter of 1 to 150 nm made of one or more of metals, alloys, and metal compounds are dispersed. The fine particle dispersion is excellent in dispersibility and storage stability, and further exhibits excellent adhesion to the substrate when the fine particle dispersion is applied to a substrate, dried and then heated and fired.

[3] About “Method for Producing Fine Particle Dispersion” as the Third Aspect “Method for Producing Fine Particle Dispersion” as the third aspect of the present invention includes:
Fine particles having an average primary particle diameter of 1 to 150 nm, consisting of one or more of metals, alloys, and metal compounds,
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
A method of producing a fine particle dispersion dispersed in
It includes at least the following steps 1 to 3.
(A) Step 1
Metal ions are reduced by electrolytic reduction or electroless reduction using a reducing agent in an aqueous solution in which at least one metal ion and a water-soluble polymer capable of forming a protective film are dissolved. An aqueous solution in which fine particles (P1) having an average particle diameter of 1 to 150 nm of primary particles made of one or more of metals, alloys, and metal compounds coated with a protective coating formed from 1 is formed. To
(B) Step 2
An agglomeration promoter is added to the aqueous solution in which the fine particles (P1) are dispersed and stirred to agglomerate or precipitate fine particles comprising one or more of the metal, alloy, and metal compound, and (i) The aggregate or precipitate is separated and collected by washing with a cleaning solvent, or (ii) the aggregate or precipitate is washed with a washing solvent after separation and collection, and one or more of metals, alloys, and metal compounds or Obtaining fine particles (P2) composed of two or more kinds,
(C) Step 3
The fine particles (P2) made of one or more of the metals, alloys, and metal compounds are redispersed in the mixed solvent (S1) or the mixed solvent (S2), and the fine particles (P2) are mixed with the mixed solvent (S1). ) Or a fine particle dispersion dispersed in the mixed solvent (S2).

Hereinafter, Steps 1 to 3 according to “Method for producing fine particle dispersion” of the third aspect will be described.
(A) Step 1
The metal ions that can be used in step 1 are the same metal ions as exemplified in the first embodiment, and the water-soluble polymer forming the protective film and the blending ratio thereof are described in the second embodiment. It is the same as that.
As the liquid phase reduction, both electrolytic reduction and electroless reduction can be employed as long as fine particles (P1) having an average primary particle diameter of 1 to 150 nm can be formed. Any known method can be employed. The metal ions used are dispersed in an aqueous solution as fine particles (P1) consisting of one or more of metals, alloys, and metal compounds coated with a protective film formed from a water-soluble polymer that is liquid-phase reduced. Exist. The metal, alloy, and metal compound are the same as the metal, alloy, and metal compound described in the first embodiment.
Examples of preferable reducing agents used in the case of electroless reduction include sodium borohydride, hydrazine, dimethylaminoborane, trimethylaminoborane, and the like, and two or more of these may be used in combination. Fine particles (P1) covered with a protective coating made of a water-soluble polymer are formed by known liquid phase reduction using the reducing agent.
In the case of electrolytic reduction, fine particles (P1) covered with a protective coating made of a water-soluble polymer are formed near the cathode by applying a potential between the anode and the cathode provided in an aqueous solution containing metal ions. The

The average particle size of the primary particles of the fine particles (P1) produced by the liquid phase reduction of the metal ions is 1-150 nm, but practically forming the fine particles (P1) with an average particle size of 2-20 nm. Is possible.
As an example of step 1, sodium borohydride or the like in the aqueous solution in which an organic protective film such as polyvinylpyrrolidone (PVP) is dissolved in copper metal ions formed from cupric acetate (II) By using a reducing agent, copper fine particles coated with a protective film made of a water-soluble polymer having an average primary particle diameter of 1 to 150 nm are formed by a reduction reaction.

(B) Step 2
The aggregation promoter that can be used in Step 2 is a halogenated hydrocarbon, and specific examples thereof include ethylene chlorohydrin, allyl chloride, ethyl chloride, benzyl chloride, methyl chloride, methylene chloride, chloronaphthalene, chloropropylene, At least one selected from chlorobenzool, chloroform, chloroprene, acetylene tetrachloride, ethane tetrachloride, carbon tetrachloride, dichloroethane, dichloroethylene, dichlorobenzole, trichloroethylene, trichloromethane, brombenzol, bromoform, and hexachloroethane Can be illustrated.
The addition amount of such an aggregation promoter is ([aggregation promoter (mol)] / [mass of metal equivalent (g)] with respect to the mass of fine particles composed of one or more of metals, alloys, and metal compounds. ]) Is preferably 0.01 to 10 and more preferably 0.1 to 1.0.

  In Step 2, when an aggregation accelerator is added to the aqueous solution in which fine particles are dispersed and the mixture is allowed to stand after stirring, for example, when chloroform having a specific gravity greater than water is used as the aggregation accelerator, The metal fine particles are separated into two phases, ie, an upper phase composed of an aqueous phase and a lower phase composed of an agglomeration accelerator, and the metal fine particles are present in a state of being concentrated and floating in the lower part of the upper aqueous phase. In the case where the specific gravity of the aggregation accelerator is smaller than that of water, after stirring, the upper phase becomes the aggregation accelerator phase and the lower phase becomes the aqueous phase. In this case, the metal fine particles are concentrated and floated below the aqueous phase. May exist in a state of being.

The state of aggregation or precipitation after the addition and stirring of the aggregation accelerator in Step 2 includes a state where fine particles are concentrated and floated below the aqueous phase as described above.
In addition, in the aqueous solution in which the fine particles (P1) before adding the aggregation accelerator are dispersed, the added water-soluble polymer is present, and a part of them is coated with the fine particles (P1). Presumed to exist. When chloroform is used among the above-mentioned aggregation accelerators, a remarkable effect can be obtained in particular that there are few chemical reactions on the surface of the metal fine particles and the coating is easy to peel off.
In addition, it is estimated that only the addition of the aggregation accelerator does not peel off all of the protective film from the fine particles, and the peeling further proceeds by washing with a washing solvent after separating the fine particles.

The operation of (i) “separating the aggregate or precipitate and washing and collecting it with a washing solvent” in step 2 is performed by, for example, supplying the aggregate or precipitate to a centrifuge and rinsing with the washing solvent. Fine particles (P2) can be recovered.
In addition, (ii) the operation of “washing with a solvent after separation / collection of the agglomerates or precipitates” is performed by separating and collecting fine particles by filtration, centrifugation, etc., then washing with a washing solvent, and then further filtering and centrifugation. Fine particles (P2) can be recovered by operation or the like.
Examples of preferable cleaning solvents that can be used for such cleaning include water and / or a C1-C6 alcohol or polyhydric alcohol having at least one hydroxyl group in the molecule. 3, the fine particle (P2) dispersion excellent in dispersibility and low-temperature sinterability can be obtained.
As an example of the operation of step 2, chloroform is added to the aqueous solution containing the fine particles (P1) having an average particle diameter of 1 to 150 nm of the primary particles coated with the water-soluble polymer protective film obtained in step 1. Is added as an agglomeration accelerator and the particle components are agglomerated or precipitated after stirring. The particle components are recovered from the aggregated or precipitated product by using a centrifuge or the like. The recovered particle component is washed a plurality of times using the above washing solvent to remove the reducing agent, the precipitation flocculant and the like.

(C) Step 3
The fine particles (P2) composed of one or more of the metals, alloys and metal compounds are redispersed in the mixed solvent (S1) or the mixed solvent (S2), and the fine particles (P2) This is a step of obtaining a fine particle dispersion dispersed in a mixed solvent.
In the third embodiment, the solvent species and the blending ratio thereof used in the mixed solvent (S1) and the mixed solvent (S2) are the same as described in the first embodiment.
As a method for redispersing the fine particles (P2) in the mixed solvent (S1) or the mixed solvent (S2), a known stirring method can be employed, but an ultrasonic irradiation method is preferably employed.
The ultrasonic irradiation time is not particularly limited and can be arbitrarily selected. For example, as shown in Example 1, when the ultrasonic irradiation time is arbitrarily set between 5 and 60 minutes, the average secondary aggregation size tends to be smaller as the irradiation time is longer.

The redispersed fine particle dispersion is stored after production until it is used, but the fine particle dispersion of the present invention is characterized by excellent storage stability. For example, as shown in Example 2, excellent fine particle dispersibility is maintained even when held for 48 hours after production, and the storage stability is excellent.
The fine particle dispersion in which the fine particles having an average primary particle diameter of 1 to 150 nm thus obtained are dispersed in the mixed solvent (S1) or the mixed solvent (S2) is, for example, at a relatively low temperature of about 200 ° C. Without using a reducing agent such as hydrogen gas, it is possible to form a conductive metal-containing thin film or metal-containing thin wire by disposing on a substrate by ink jet and drying and firing.
There is no restriction | limiting in particular in the said board | substrate, Glass, a polyimide, etc. can be used by a use purpose etc., and drying and baking are performed in inert gas atmosphere, such as argon. Although drying conditions depend on the polar solvent to be used, for example, it is about 15 to 30 minutes at 100 to 200 ° C., and the firing conditions are about 20 to 40 minutes at 190 to 250 ° C., for example, although it depends on the coating thickness, preferably It is about 20 to 40 minutes at 190 to 220 ° C.
The metal-containing thin film or metal-containing thin wire thus obtained has conductivity, and its electric resistance value is 1.0 Ωcm or less, for example, 1.0 × 10 ⁻⁵ Ωcm to 10 × 10 ^−4. It is possible to achieve about Ωcm. Furthermore, the metal-containing thin film is excellent in substrate adhesion.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the methods described in the following examples.
In the following examples and comparative examples, the average particle size of primary particles in the fine particle dispersion is determined by observation with a transmission electron microscope, and the secondary aggregate size is determined by a dynamic light scattering type particle size distribution analyzer. The particle size distribution was measured by (Zeta Sizer Nano Series).
[Example 1, Comparative Example 1]
The dispersion efficiency of the copper fine particle dispersion was evaluated as follows.
(1) Preparation of copper fine particle dispersion First, copper fine particles coated with an organic protective film composed of a water-soluble polymer were prepared by the following procedure.
First, 10 ml of an aqueous copper acetate solution in which 0.2 g of copper acetate ((CH ₃ COO) ₂ Cu · 1H ₂ O) was dissolved in 10 ml of distilled water as a raw material for copper fine particles, and 5.0 mol / liter (as a metal ion reducing agent) 100 ml of an aqueous sodium borohydride solution prepared by mixing sodium borohydride and distilled water so as to be 1) was prepared. Thereafter, 0.5 g of polyvinyl pyrrolidone (PVP, number average molecular weight of about 3500) as a water-soluble polymer for forming a protective film is added to the sodium borohydride aqueous solution, and the mixture is stirred and dissolved. Then, 10 ml of the aqueous copper acetate solution was added dropwise.
As a result of reacting this mixed liquid with sufficient stirring for about 60 minutes, a fine particle dispersion in which copper fine particles having a particle diameter of 5 to 10 nm were dispersed in an aqueous solution was obtained.

  Next, 5 ml of chloroform as an aggregation accelerator was added to 100 ml of the dispersion liquid in which the copper fine particles obtained by the above method were dispersed, and stirred well. After stirring for several minutes, the reaction solution was put into a centrifuge, and copper fine particles were collected by precipitation. After that, the obtained particles and 30 ml of distilled water are put into a test tube, stirred well using an ultrasonic homogenizer, and then washed three times with water to collect the particle components with a centrifuge, followed by the same test tube. Inside, the obtained copper fine particles and 30 ml of 1-butanol were added and stirred well, and then alcohol washing for recovering the copper fine particles with a centrifuge was performed three times.

The volume of the copper fine particles recovered by the above steps is shown in Examples 1-1 to 5 in Table 1 with N-methylacetamide as the organic solvent (A) of the present invention and diethyl ether as the organic solvent (B). The fine particle dispersion of the present invention was obtained by dispersing each in 10 ml of the solvent mixed at a ratio and applying ultrasonic vibration to the dispersion using an ultrasonic homogenizer for a predetermined time shown in Table 1.
As a comparative example, the above-described copper fine particles were dispersed in 10 ml of a solvent in which N-methylacetamide and diethyl ether were mixed at a volume ratio shown in Table 1, and then Comparative Examples 1-1 and 2 in Table 1 were also made. A fine particle dispersion in which ultrasonic vibration was applied to the dispersion using an ultrasonic homogenizer for a predetermined time shown in FIG.
Since the solution in which N-methylacetamide and diethyl ether were mixed at a volume ratio of 98: 2 (Comparative Example 1-1) was solid at room temperature (20 ° C.), the above experiment was conducted by heating to 30 ° C. did. For other mixed solvents, the above experiment was performed at room temperature (20 ° C.).

(2) Evaluation of the dispersion efficiency of the copper fine particle dispersion The average particle diameter (primary particles) of the fine particles in the fine particle dispersion obtained above was observed by a transmission electron microscope, and the secondary agglomeration size was changed. Table 1 shows the results of evaluation by particle size distribution measurement using a dynamic light scattering particle size distribution analyzer (Zetasizer Nano Series). As a result, in both Examples 1-1 to 5 and Comparative Examples 1-1 and 2, although the average particle size of the fine particles does not change significantly from 15 nm to 20 nm, the secondary aggregation size and the dispersion efficiency thereof are greatly different. By dispersing copper fine particles in the mixed solvent (mixed solvent (S1)) composed of the organic solvent (A) and the organic solvent (B) of the present invention in Examples 1-1 to 5 to finely disperse fine particles efficiently. It was confirmed that a liquid was obtained. On the other hand, Comparative Examples 1-1 and 2 were inferior in dispersibility of the fine particles as compared with the above Examples.

[Example 2, Comparative Example 2]
An experiment for evaluating the storage stability of the copper fine particle dispersion was performed as follows.
(1) Preparation of copper fine particle dispersion The copper fine particles prepared by the method described in Example 1 were prepared using N-methylacetamide as the organic solvent (A) of the present invention, diethyl ether as the organic solvent (B), and an organic solvent ( As C), ethylene glycol is dispersed in 10 ml of the solvent mixed in the volume ratio shown in Examples 2-1 and 2 in Table 2, and ultrasonic vibration is applied to the dispersion using an ultrasonic homogenizer for 1 hour. The prepared fine particle dispersion was prepared.
Further, as comparative examples, copper fine particles produced by the method described in Example 1 were prepared by using N-methylacetamide as the organic solvent (A) of the present invention, diethyl ether as the organic solvent (B), and ethylene as the organic solvent (C). Glycol was dispersed in 10 ml of the solvent mixed in the volume ratios shown in Comparative Examples 2-1 and 2 in Table 2 and further, as Comparative Example 2-3, dispersed in 10 ml of a solvent containing only ethylene glycol, and an ultrasonic homogenizer was used for 1 hour. An ultrasonic vibration was applied to the dispersion to prepare a fine particle dispersion.

(2) Evaluation of Storage Stability of Copper Fine Particle Dispersion In order to evaluate the storage stability of the copper fine particle dispersion obtained above, fine particles after being stored at room temperature (20 ° C.) for a predetermined time shown in Table 2, respectively. The particle size distribution (secondary aggregate size) was measured using a dynamic light scattering type particle size distribution analyzer (Zetasizer Nano Series). The results are shown in Table 2.
From the measurement results, the copper fine particles are dispersed in a mixed solvent (mixed solvent (S2)) composed of the organic solvent (A), the organic solvent (B), and the organic solvent (C) of the present invention, so that it is maintained for a long time after the preparation. As a result, it was confirmed that a fine particle dispersion having high storage stability and high storage stability can be obtained.

[Example 3, Comparative Example 3]
The conductivity of the fired film obtained from the fine particle dispersion was evaluated.
Examples prepared by the method described in Example 1 and dispersed in the mixed solvent (mixed solvent (S1)) shown in Table 3 containing the organic solvent (A) of the present invention and the organic solvent (B). 3 and 1 (corresponding to those prepared in Examples 1-2 and 1-4, respectively), and the organic solvent (A), organic solvent (B), and organic solvent (C) of the present invention. , Fine particle dispersions of Examples 3-3 and 4 (corresponding to those prepared in Examples 2-1 and 2-2, respectively) dispersed in a mixed solvent (mixed solvent (S2)) shown in Table 3. In addition, as Comparative Example 3, a copper nanoparticle dispersion (trade name: Cu nanometal ink “Cu1T”) manufactured by ULVAC, Inc. was applied on a glass substrate (size: 2 cm × 2 cm), and then in a nitrogen atmosphere at 210 ° C. A fired film was obtained by heat treatment for 1 hour. The electric resistance of the fired film thus obtained was measured by a direct current four-terminal method (use measuring machine: Digital Multimeter DMM2000 type (four-terminal electric resistance measurement mode)) manufactured by Keithley.
Table 3 shows the measurement results. From Table 3, the coated solvent of the mixed solvent (mixed solvent (S1)) of the present invention and the fine particle dispersion dispersed in the mixed solvent (mixed solvent (S2)) is heat-treated at 210 ° C. for 1 hour in a nitrogen atmosphere. However, it has been found that a fired film having good conductivity can be obtained.

[Example 4, Comparative Example 4]
As the mixed solvent, the substrate adhesion of the fine particle dispersion dispersed in the mixed solvent (S2) used in Example 2 was evaluated as follows.
According to the method described in Example 1, the copper fine particles were composed of the organic solvent (A), the organic solvent (B), and the organic solvent (C) of the present invention. Examples 4-1 to 2 in Table 4 (Example 2) -Disperse each in 10 ml of the solvent mixed in the volume ratio shown in (1 to 2) and apply ultrasonic vibration to the dispersion for 1 hour using an ultrasonic homogenizer. Was prepared. As a comparative example, the copper fine particles were dispersed in 10 ml of a solvent mixed at a volume ratio shown in Comparative Examples 4-1 to 3 in Table 4 (corresponding to those prepared in Comparative Examples 2-1 to 2-3, respectively). A fine particle dispersion was prepared by applying ultrasonic vibration to the dispersion using an ultrasonic homogenizer for 1 hour.

Each of these fine particle dispersions was coated on a glass substrate (size: 2 cm × 2 cm), dried at 140 ° C. in a nitrogen atmosphere, and then heat treated at 210 ° C. for 1 hour in a nitrogen atmosphere to obtain a fired film. . A crosscut tape peeling test (1 mm width crosscut 10 × 10, tape used: manufactured by Teraoka Seisakusho, model number 631S # 25) was performed on the obtained fired film. The results are shown in Table 4.
From the results in Table 4, tape peeling was not observed in the fired films (Examples 4-1 and 2) in which the fine particle dispersion dispersed in the mixed solvent (S2) of the present invention was applied onto a glass substrate and fired. On the other hand, in Comparative Examples 4-1 to 3, tape peeling or partial tape peeling was interspersed.
From the above, it was confirmed that the fired film obtained by applying and firing the fine particle dispersion dispersed in the mixed solvent (S2) of the present invention on the glass substrate has strong substrate adhesion.

Claims (26)

Fine particles having an average primary particle diameter of 1 to 150 nm, consisting of one or more of metals, alloys, and metal compounds,
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
A fine particle dispersion characterized by being dispersed in   The organic solvent (A) is N-methylacetamide, N-methylformamide, N-methylpropanamide, formamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide The fine particle dispersion according to claim 1, which is one or more selected from 1-methyl-2-pyrrolidone, hexamethylphosphoric triamide, 2-pyrrolidinone, ε-caprolactam, and acetamide. . The organic solvent (B) has the general formula ^{R 1 -O-R 2 (R} 1, R 2 are alkyl groups individually, the number of carbon atoms is 1-4.) Ether compound represented by (B1), an alcohol (B2) represented by the general formula R ³ —OH (R ³ is an alkyl group having 1 to 4 carbon atoms), R ⁴ —C (═O) —R ⁵ (R ⁴ and R ⁵ are each independently an alkyl group having 1 to 2 carbon atoms) and a ketone compound (B3) represented by the general formula R ⁶ — (N—R ⁷ ) — R ⁸ (R ⁶ , R ⁷ , R ⁸ are each independently an alkyl group or hydrogen, and is selected from amine compounds (B4) represented by hydrogen having 0 to 2 carbon atoms). The fine particle dispersion according to claim 1, wherein the fine particle dispersion is one type or two or more types.   The ether compound (B1) is selected from diethyl ether, methyl propyl ether, dipropyl ether, diisopropyl ether, methyl-t-butyl ether, t-amyl methyl ether, divinyl ether, ethyl vinyl ether, and allyl ether. The fine particle dispersion according to claim 3, which is one type or two or more types.   The said alcohol (B2) is 1 type (s) or 2 or more types selected from methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, and 2-methyl 2-propanol. Fine particle dispersion.   The fine particle dispersion according to claim 3, wherein the ketone compound (B3) is one or more selected from acetone, methyl ethyl ketone, and diethyl ketone.   The fine particle dispersion according to claim 3, wherein the amine compound (B4) is triethylamine and / or diethylamine.   The organic solvent (C) is ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, glycerol, 1,1,1-trishydroxymethylethane 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butanetriol, glycerol, threitol The fine particle fraction according to claim 1, which is one or more selected from erythritol, pentaerythritol, pentitol and hexitol. Liquid.   The metal is selected from copper, silver, gold, nickel, cobalt, iron, zinc, tin, aluminum, bismuth, platinum, rhodium, palladium, ruthenium, rhodium, manganese, chromium, vanadium, and titanium The fine particle dispersion according to any one of claims 1 to 8, wherein two or more kinds, the alloy is an alloy composed of two or more kinds of the metal, and the metal compound is an oxide of the metal and the alloy. Fine particles having an average primary particle diameter of 1 to 150 nm, consisting of one or more of metals, alloys, and metal compounds,
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
A method of producing a fine particle dispersion dispersed in
(I) In an aqueous solution containing a water-soluble polymer capable of forming a protective film, fine particles having an average particle diameter of primary particles of 1 to 150 nm composed of one or more of the metals, alloys, and metal compounds. Or a step of forming a dispersion state in which the metal ions are reduced by electrolytic reduction or electroless reduction using a reducing agent in an organic solvent and coated with a protective film formed from the water-soluble polymer, and then (ii) ) A method for producing a fine particle dispersion, comprising the step of adding a coagulation promoter in the aqueous solution or organic solvent to aggregate or precipitate the microparticles and recovering.   The organic solvent (A) is N-methylacetamide, N-methylformamide, N-methylpropanamide, formamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide The fine particle dispersion according to claim 10, which is one or more selected from 1-methyl-2-pyrrolidone, hexamethylphosphoric triamide, 2-pyrrolidinone, ε-caprolactam, and acetamide. Manufacturing method. The organic solvent (B) is an ether compound represented by the general formula R ¹ —O—R ² (wherein R ¹ and R ² are each independently an alkyl group and has 1 to 4 carbon atoms). (B1), an alcohol (B2) represented by the general formula R ³ —OH (R ³ is an alkyl group having 1 to 4 carbon atoms), R ⁴ —C (═O) —R ⁵ (R ⁴ and R ⁵ are each independently an alkyl group having 1 to 2 carbon atoms) and a ketone compound (B3) represented by the general formula R ⁶ — (N—R ⁷ ) — R ⁸ (R ⁶ , R ⁷ , R ⁸ are each independently an alkyl group or hydrogen, and is selected from amine compounds (B4) represented by hydrogen having 0 to 2 carbon atoms). The method for producing a fine particle dispersion according to claim 10, wherein the fine particle dispersion is one type or two or more types.   The organic solvent (C) is ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, glycerol, 1,1,1-trishydroxymethylethane 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butanetriol, glycerol, threitol The fine particles according to claim 10, wherein the fine particles are one or more selected from erythritol, pentaerythritol, pentitol, and hexitol. Method of manufacturing a dispersion liquid.   The water-soluble polymer is one or more selected from polyvinyl pyrrolidone, polyethyleneimine, polyacrylic acid, carboxymethylcellulose, polyacrylamide, polyvinyl alcohol, polyethylene oxide, starch, and gelatin. 14. The method for producing a fine particle dispersion according to any one of 10 to 13.   The aggregation accelerator is ethylene chlorohydrin, allyl chloride, ethyl chloride, benzyl chloride, methyl chloride, methylene chloride, chloronaphthalene, chloropropylene, chlorobenzole, chloroform, chloroprene, acetylene tetrachloride, ethane tetrachloride, carbon tetrachloride, The fine particle according to any one of claims 10 to 14, which is one or more selected from dichloroethane, dichloroethylene, dichlorobenzol, trichloroethylene, trichloromethane, bromobenzol, bromoform, and hexachloroethane. A method for producing a dispersion. Fine particles having an average primary particle diameter of 1 to 150 nm, consisting of one or more of metals, alloys, and metal compounds,
A mixed solvent (S1) containing 50% to 95% by volume of an organic solvent (A) having an amide group and 5% by volume or more of a low boiling point organic solvent (B) having a boiling point of 20 to 100 ° C. at normal pressure;
Alternatively, the organic solvent (A) having an amide group (A) is 50 to 94% by volume, the low boiling point organic solvent (B) is 20 to 100 ° C. at a normal pressure, and the boiling point at normal pressure is 100 ° C. Mixed solvent (S2) containing 1% by volume or more of an organic solvent (C) composed of an alcohol and / or a polyhydric alcohol having an excess and one or more hydroxyl groups in the molecule
A method of producing a fine particle dispersion dispersed in
A method for producing a fine particle dispersion, comprising at least the following steps 1 to 3.
(A) Step 1
Metal ions are reduced by electrolytic reduction or electroless reduction using a reducing agent in an aqueous solution in which at least one metal ion and a water-soluble polymer capable of forming a protective film are dissolved. An aqueous solution in which fine particles (P1) having an average particle diameter of 1 to 150 nm of primary particles made of one or more of metals, alloys, and metal compounds coated with a protective coating formed from 1 is formed. To
(B) Step 2
An agglomeration promoter is added to the aqueous solution in which the fine particles (P1) are dispersed and stirred to agglomerate or precipitate fine particles comprising one or more of the metal, alloy, and metal compound, and (i) The aggregate or precipitate is separated and collected by washing with a cleaning solvent, or (ii) the aggregate or precipitate is washed with a washing solvent after separation and collection, and one or more of metals, alloys, and metal compounds or Obtaining fine particles (P2) composed of two or more kinds,
(C) Step 3
The fine particles (P2) made of one or more of the metals, alloys, and metal compounds are redispersed in the mixed solvent (S1) or the mixed solvent (S2), and the fine particles (P2) are mixed with the mixed solvent (S1). ) Or a fine particle dispersion dispersed in the mixed solvent (S2).   The metal ion in the step 1 is selected from copper, silver, gold, nickel, cobalt, iron, zinc, tin, aluminum, bismuth, platinum, rhodium, palladium, ruthenium, rhodium, manganese, chromium, vanadium, and titanium. The manufacturing method of the fine particle dispersion of Claim 16 which is a metal ion of 1 type, or 2 or more types of metals.   The water-soluble polymer in the step 1 is one or more selected from polyvinylpyrrolidone, polyethyleneimine, polyacrylic acid, carboxymethylcellulose, polyacrylamide, polyvinyl alcohol, polyethylene oxide, starch, and gelatin. The method for producing a fine particle dispersion according to claim 16 or 17.   19. The method according to claim 16, wherein the reducing agent in Step 1 is one or more selected from sodium borohydride, hydrazine, dimethylaminoborane, and trimethylaminoborane. A method for producing a fine particle dispersion.   In the step 2, the aggregation accelerator is ethylene chlorohydrin, allyl chloride, ethyl chloride, benzyl chloride, methyl chloride, methylene chloride, chloronaphthalene, chloropropylene, chlorobenzole, chloroform, chloroprene, acetylene tetrachloride, ethane tetrachloride, 20. One or more selected from carbon tetrachloride, dichloroethane, dichloroethylene, dichlorobenzole, trichloroethylene, trichloromethane, brombenzol, bromoform, and hexachloroethane, respectively. A method for producing a fine particle dispersion described in 1.   The cleaning solvent used in the step 2 is water and / or a C1-C6 alcohol or a polyhydric alcohol having at least one hydroxyl group in the molecule. A method for producing the fine particle dispersion described.   The organic solvent (A) used in Step 3 is N-methylacetamide, N-methylformamide, N-methylpropanamide, formamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N , N-dimethylformamide, 1-methyl-2-pyrrolidone, hexamethylphosphoric triamide, 2-pyrrolidinone, ε-caprolactam, and acetamide. 21. The method for producing a fine particle dispersion according to any one of 21. The organic solvent (B) used in the step 3 is represented by the general formula R ¹ —O—R ² (wherein R ¹ and R ² are each independently an alkyl group and have 1 to 4 carbon atoms). An ether compound (B1), a general formula R ³ —OH (R ³ is an alkyl group and has 1 to 4 carbon atoms), an alcohol (B 2), a general formula R ⁴ —C ^{(= O) -R 5 (.} R 4, R 5 are alkyl groups individually, the number of carbon atoms is 1 to 2) an amine based compound (B3), and the general formula ^{R 6} - (N—R ⁷ ) —R ⁸ (R ⁶ , R ⁷ , and R ⁸ are each independently an alkyl group or hydrogen, and the number of carbon atoms is 0 to 2). 23) The method for producing a fine particle dispersion according to any one of claims 16 to 22, which is one or more selected from the group consisting of .   The organic solvent (C) used in Step 3 is ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3. -Butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, glycerol, 1,1,1 -Trishydroxymethylethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butanetriol, glycero 2. One or more selected from the group consisting of benzene, threitol, erythritol, pentaerythritol, pentitol and hexitol. Method for producing a particulate dispersion according to any one of to 23.   When redispersing the fine particles (P2) of one or more of the metals, alloys, and metal compounds in the mixed solvent (S1) or the mixed solvent (S2) in the step 3, an ultrasonic wave is irradiated. The method for producing a fine particle dispersion according to any one of claims 16 to 24, wherein:   The metal is selected from copper, silver, gold, nickel, cobalt, iron, zinc, tin, aluminum, bismuth, platinum, rhodium, palladium, ruthenium, rhodium, manganese, chromium, vanadium, and titanium The fine particle dispersion according to any one of claims 16 to 25, wherein two or more kinds, the alloy is an alloy composed of two or more kinds of the metals, and the metal compound is an oxide of the metal and the alloy. Production method.