JP2002294307A - Metallic colloidal solution, production method therefor, electrically conductive ink and electrically conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic colloidal solution which is produced by a simple production method and has high dispersibility, and exhibits high electric conductivity. SOLUTION: The metallic colloidal solution contains at least one kind of compound selected from the groups consisting of polyene polycarboxylic acid, the derivative thereof in a carboxylic group, and the salts thereof. Preferably, the above polyene polycarboxylic acid is a compound expressed by the formula (1) [in the formula, (n) is an integer of 0 to 5; and (m) is an integer of 1 or 2; wherein, (m) is 1 when (n) is zero]. In the method for producing the metallic colloidal solution by reducing metallic salt with a reducing agent, the reducing agent consists of tannic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal colloid liquid which can be produced more easily and at lower cost than conventional methods, and a method for producing the same.

[0002]

2. Description of the Related Art Various compounds are known as a metal compound, a dispersant, and a reducing agent used for preparing a metal colloid solution. In the examples of JP-A-10-66861, silver nitrate as a metal compound, sodium citrate as a dispersant, and ferrous sulfate as a reducing agent are used, and after controlling these at a temperature of 2000 to 6000 rpm under stirring. An appropriate mixing and reaction was performed to obtain a colloidal solution of silver fine particles, and the solid content obtained by sedimentation and separation was 0.4%.
Remove iron by adding it to a molar sodium nitrate solution,
Further, a silver solid content obtained by centrifugation at a gravity of 3000 G was obtained.
It is described that a silver colloid liquid used for a coating material for forming a transparent conductive film is obtained by redispersing it in water.

On the other hand, Japanese Patent Application Laid-Open No. 2000-87122 discloses that the metal compound, dispersant and reducing agent used are the same, but in order to make up for the disadvantages of the technology described in the examples of Japanese Patent Application Laid-Open No. 10-66861, The reaction is carried out in an atmosphere that does not contain oxygen, the reaction solution is decanted to separate a solid content, desalted by dialysis, and a silver colloid solution used for a coating material for forming a transparent conductive film, or It is described to obtain a mixed colloid liquid of silver and palladium.

JP-A-11-80647 discloses that a high molecular weight pigment dispersant having a specific structure having a number average molecular weight of 2,000 to 1,000,000 is used as a high molecular weight dispersant and alcohol is used as a reducing agent. This describes that a colloidal solution of a noble metal or copper used for a color material having high saturation is obtained.

[0005] The metal colloid liquid obtained by each of the above methods is excellent as a metal colloid liquid used for a specific application, but the metal colloid liquid is a conductive ink which is required to have higher conductivity than a transparent conductive film. It has been found that there are various problems in the case of using it.

[0006] JP-A-10-66861 and JP-A-20
It has been found that the methods described in JP-A-00-87122 cannot obtain the desired high conductivity. Further, these methods require various production steps under special conditions, and particularly the batch processing. Because of the necessity of the centrifugal separation process, it has been found that it becomes an obstacle to cost reduction in making mass production equipment. When adding a small amount of metal colloid to a transparent conductive material that is originally expensive, as in the field of transparent conductive films for displays, expensive metal colloids manufactured under special conditions can be used. In the case of a conductive ink containing a colloid liquid as a main component, cost reduction is strongly demanded.

According to the technique described in JP-A-11-80647, the number average molecular weight is from 2000 to 1,000,000
By adding about 6.3 g of a high molecular weight pigment dispersant having the above specific structure to 1 g of metal, a colloidal solution of a noble metal or copper which is hard to aggregate can be obtained. When a polymer-based dispersant is used, the periphery of the metal colloid particles is covered with a large amount of organic components to increase the dispersion stability, but when used in a conductive ink, the organic components increase the volume resistance value, while In order to remove the organic components, it was necessary to perform a heat treatment at a considerably high temperature, and in that case, it was found that gas was released from the surface of the film, and a hole was formed in the film.

[0008] As described above, with the combinations of the starting materials known so far, the desired high conductivity cannot be obtained, or it is necessary to carry out the reaction under highly restricted production conditions in order to disperse uniformly, When a high molecular pigment dispersant is used to enhance the property, there is a problem that conductivity is sacrificed.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a high dispersibility by a simple production method,
It is an object of the present invention to provide a metal colloid liquid exhibiting high conductivity.

[0010]

SUMMARY OF THE INVENTION The present invention provides at least one compound selected from the group consisting of polyene polycarboxylic acids, derivatives at carboxyl groups, and salts thereof.
Metal colloid liquid containing various compounds. Hereinafter, the present invention will be described in detail.

As a result of various studies on the metal colloid solution, the present inventors have found that by using a specific dispersant, the atmosphere, temperature and stirring speed can be controlled without special control.
The present inventors have found that a high dispersibility can be obtained by a simple production method and that a metal colloid liquid exhibiting high conductivity can be obtained, and the present invention has been accomplished.

The metal colloid solution of the present invention is characterized by containing a polyene polycarboxylic acid, a derivative at a carboxyl group thereof, or a salt thereof (hereinafter, also collectively referred to as polyene polycarboxylic acid). I do. These compounds can function as dispersants in the metal colloid liquid. These may be used alone or in combination of two or more.

Citric acid or citrate, exemplified as a dispersant in many prior art documents, is a low molecular weight dispersant having one hydroxyl group and three carboxyl groups. Since citric acid and citrate having three carboxyl groups can favorably disperse metal colloid particles by the electric repulsion of ionized carboxyl groups, they have been often used as dispersants.

However, since citrate has a low adsorption efficiency on the surface of the metal colloid particles, it is necessary to add a large amount of citrate in order to enhance dispersibility.
A large amount of dispersant not directly adsorbed on the metal colloid particles remains in the metal colloid liquid. Since these dispersants are organic substances, they increase the volume resistance value of the metal colloid liquid and deteriorate the performance as a conductive ink. In order to remove such organic substances, complicated post-treatments such as centrifugation and ultrafiltration are required.

On the other hand, in the metal colloid solution of the present invention, polyene polycarboxylic acids can function as a dispersant, but polyene polycarboxylic acids have at least one C ＝ C double bond and at least one carboxyl group. It is. Since the C = C double bond is excellent in the adsorptivity to the metal particle surface, the polyene polycarboxylic acids can be efficiently adsorbed to the metal particle surface. The present inventor has found that when such a polyene polycarboxylic acid is used as a dispersant for a metal colloid solution, high dispersibility can be obtained with a minimum necessary dispersant amount. That is,
If polyene polycarboxylic acids are used as the dispersant in the metal colloid solution, the amount of the dispersant to be added can be extremely small, so that a colloid solution having a small organic substance content affecting conductivity can be used without performing centrifugation or ultrafiltration. Obtainable.

The polyene polycarboxylic acids used in the present invention are not particularly restricted but include, for example, compounds represented by the following general formula (1), derivatives thereof, and salts thereof. These compounds are referred to as WO99
/ 46231.

[0017]

Embedded image

In the formula, n represents an integer of 0 to 5, and m represents an integer of 1 or 2. However, when n is 0, m is 1. Among the polyene polycarboxylic acids represented by the general formula (1), those wherein m = 1 and n = 0,
Preferably, m = 2 and n = 1, and m = 2 and n = 2.

The polyene polycarboxylic acid represented by the above general formula (1), its acid anhydride, or salts thereof is obtained by culturing a microorganism belonging to the genus Talalomyces in a culture medium, Can be produced.

Among the polyene polycarboxylic acids represented by the above general formula (1), a polyene polycarboxylic acid having m = 1 and n = 0 is an R0 compound, and a polyene polycarboxylic acid having m = 2 and n = 0. The carboxylic acid is a S0 compound, m = 2 and n =
A polyene polycarboxylic acid as S1 compound, m = 2
And polyene polycarboxylic acid where n = 2 is abbreviated as S2 compound. Further, the above R0 compound, S0 compound, S
In Compound 1 and Compound S2, those in which two carboxy groups bonded to adjacent carbon atoms are all bonded to form an acid anhydride group are R0 anhydride, S0 anhydride, and Sl, respectively.
Abbreviated as anhydride and S2 anhydride. These structural formulas are shown below.

[0021]

Embedded image

[0022]

Embedded image

[0023]

Embedded image

The metal colloid liquid of the present invention comprises a solid content mainly composed of particles composed of a metal component and an organic component (hereinafter referred to as metal colloid particles), and a solvent. Examples of the metal include gold, silver, copper, platinum, palladium, rhodium, ruthenium, iridium, and osmium. Among them, silver, copper, platinum and palladium are preferred. These metals may be used alone,
Two or more kinds may be used in combination.

As the above metal, it is preferable to use silver and another metal in combination. The use of silver improves the conductivity of the film formed using the metal colloid solution, but when silver is used as the electronic material, it is necessary to consider the problem of migration. By using a mixed metal colloid liquid composed of silver and other metals, migration hardly occurs. Examples of the other metals include gold, copper, platinum, palladium, rhodium, ruthenium, iridium, and osmium. Among them, copper, platinum and palladium are preferred.

When silver and another metal are used in combination, the weight ratio of silver to the other metal in the metal colloid liquid should be 99: 1 to 30:70. Is preferred. When the silver ratio exceeds 99% by weight,
It is difficult to solve the migration property. On the other hand, when the proportion of silver is less than 30% by weight, the conductivity of the obtained metal colloid solution may be reduced. More preferably, it is 95: 5 to 40:60, and still more preferably,
90:10 to 60:40.

The metal content of the metal colloid solution of the present invention is preferably from 1 to 500 g / L. 1g
If it is less than / L, it is too thin to increase the number of times of coating to obtain a desired film thickness, and if it exceeds 500 g / L, the viscosity becomes too high and it becomes difficult to handle.

The organic component includes a dispersant, a reducing agent and the like, and also includes the polyene polycarboxylic acids and the like. The above polyene polycarboxylic acids can function as a dispersant in the metal colloid solution of the present invention, but this does not exclude the addition of other dispersants. Other dispersants may be added as long as the effect of the metal colloid liquid is not impaired.

The other dispersant is not particularly limited as long as it dissolves in a suitable solvent and exhibits a dispersing effect. For example, trisodium citrate, tripotassium citrate, trilithium citrate, malic acid Ionic compounds such as disodium, disodium tartrate, and sodium glycolate; sodium dodecylbenzenesulfonate, sodium oleate, polyoxyethylene alkyl ether,
Surfactants such as perfluoroalkylethylene oxide adducts; and polymers such as gelatin, gum arabic, albumin, polyethyleneimine, polyvinyl celluloses, and alkanethiols. These dispersants may be used alone or in combination of two or more.

In the metal colloid liquid of the present invention, the form of the metal colloid particles is not particularly limited. For example, particles having an organic component adhered to the surface of the above-mentioned metal component particles and particles composed of the metal component may be used as a core. Examples thereof include particles whose surface is coated with an organic component, particles obtained by uniformly mixing a metal component and an organic component, and the like. Among them, particles having a metal component as a core and the surface thereof coated with an organic component, and particles obtained by uniformly mixing a metal component and an organic component are preferable.

In the present invention, the amount of the organic component in the metal colloid particles is preferably 1 to 30% by weight. If the amount is less than 1% by weight, the storage stability of the obtained metal colloid solution tends to be poor, and if it exceeds 30% by weight, the conductivity of the conductive film formed using the obtained metal colloid solution is poor. Tend to be. More preferably, it is 2 to 20% by weight.

The solvent used in the metal colloid solution of the present invention is preferably water and / or a water-soluble solvent. By using water and / or a water-soluble solvent, the conductive ink produced from the metal colloid liquid does not have a strong solvent odor at the time of drying or baking, and has little adverse effect on the environment.

Since the metal colloid liquid of the present invention comprises a solid containing metal colloid particles as a main component and a solvent, the electric conductivity can be reduced to 10 mS / cm or less. The conventional metal colloid solution reacts sensitively to the concentration of the existing electrolyte component to cause coagulation and sedimentation, and storage stability may be impaired. However, if the conductivity is 10 mS / cm or less, this effect is sufficiently reduced. It is possible to prevent the outflow of alkali due to storage in a glass container and the deterioration of storage stability due to an increase in electrolyte concentration over time due to dissolution of carbon dioxide in air. Further, when the conductivity of the metal colloid liquid is 10 mS / cm or less, the dispersion stability of the metal colloid liquid is high, so that it is easy to prepare a metal colloid liquid having a high solid content, and the volume can be reduced.
Easy handling during distribution and transportation. When the concentration of the metal colloid solution of the present invention is high, the concentration may be adjusted to an optimum concentration using an appropriate solvent when used.

In the metal colloid liquid of the present invention, the concentration of the solid content containing the above-mentioned metal colloid particles as a main component (hereinafter, also simply referred to as solid content) is preferably 1 to 70% by weight. Here, the solid content refers to a solid content of 7% after removing most of the water from the aqueous metal colloid solution using silica gel or the like.
It means the solid content remaining when dried at a temperature of 0 ° C. or lower, and usually, this solid content comprises metal colloid particles, a residual dispersant, a residual reducing agent, and the like.

When the solid content is less than 1% by weight, the metal content is too small. Therefore, when forming a conductive film using the obtained metal colloid solution, it is necessary to obtain a necessary thickness. This is industrially disadvantageous because it requires repeated coating. On the other hand, when the concentration of the solid content exceeds 70% by weight,
This is also industrially disadvantageous because the viscosity increases and it becomes difficult to handle. More preferably, it is 3 to 50% by weight.

In the metal colloid solution of the present invention, the weight loss by heating to 100 to 500 ° C. by thermogravimetric analysis of the solid content is preferably 1 to 25% by weight. When the solid content is heated to 500 ° C., an organic component, a residual dispersant,
The residual reducing agent and the like are oxidatively decomposed, and most of them are gasified and disappear. Since the amounts of the residual dispersing agent and the residual reducing agent are considered to be insignificant, the loss by heating up to 500 ° C. may be considered to substantially correspond to the amount of the organic component in the solid content.

The solid content was determined to be 100 to 5 by thermogravimetric analysis.
A metal colloid aqueous solution having a heating loss to 00 ° C. of 1 to 25% by weight is excellent in dispersion stability and also has an appropriate amount of a component such as an organic component which causes deterioration in conductivity. In addition, a conductive film having excellent conductivity can be formed.

If the weight loss on heating of the solid content is less than 1% by weight, sufficient dispersibility of the metal colloid particles may not be obtained because the amount of the organic component relative to the metal component is small, and it may exceed 25% by weight. And, since the amount of the organic component relative to the metal component is too large, the conductivity of the obtained conductive coating may be considerably deteriorated. When the amount of the organic component is large, the conductivity can be improved to some extent by decomposing and eliminating the organic component by heating and baking after film formation, but it is not preferable because cracks and the like easily occur in the conductive film. More preferably, it is 1 to 10% by weight.

In the metal colloid liquid of the present invention, the average particle diameter of the metal colloid particles is preferably 1 to 400 nm. If it is less than 1 nm, a good conductive ink can be obtained, but the production of such fine particles is generally expensive and impractical. On the other hand, if it exceeds 400 nm, the dispersion stability of the metal colloid particles tends to change with time. More preferably, it is 1 to 70 nm.

The method for producing the metal colloid liquid of the present invention is not particularly limited, and includes, for example, a method of first preparing a solution containing metal colloid particles, and then washing the solution. The method for preparing the solution containing the metal colloid particles is not particularly limited as long as it is a method by a chemical reduction method. For example, a metal salt (metal ion) dispersed in a solution using the polyene polycarboxylic acid is used.
May be reduced by any method.

The metal salt is not particularly limited as long as it can be dissolved in an appropriate solvent and can be reduced by any means. Examples thereof include silver nitrate, silver sulfate, silver chloride, silver oxide, silver acetate, silver nitrite, Silver salts such as silver chlorate and silver sulfide; gold salts such as chloroauric acid, potassium potassium chloride and sodium gold chloride; platinum salts such as chloroplatinic acid, platinum chloride, platinum oxide and potassium chloroplatinate; palladium nitrate and acetic acid Examples include palladium salts such as palladium, palladium chloride, palladium oxide, and palladium sulfate, and other white metal salts. These metal salts may be used alone or in combination of two or more.

The method for reducing the metal salt is not particularly limited, and the metal salt may be reduced using a reducing agent, or may be reduced using light such as UV, an electron beam, or heat energy. The reducing agent is not particularly limited as long as it can be dissolved in an appropriate solvent and can reduce the metal salt.Examples include amine compounds such as dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone, and hydrazine. Sodium borohydride;
Hydrogen compounds such as hydrogen iodide and hydrogen gas; oxides such as carbon monoxide and sulfurous acid; ferrous sulfate, iron chloride, iron fumarate, iron lactate, iron oxalate, iron sulfide, tin acetate, tin chloride, and tin chloride Low valent metal salts such as tin phosphate, tin oxalate, tin oxide, tin sulfate;
Organic compounds such as formaldehyde, hydroquinone, pyrogallol, tannin, tannic acid, salicylic acid, and sugars such as D-glucose can be mentioned. Above all,
Tannic acid is preferably used. When tannic acid is used as the reducing agent, the obtained metal colloid exhibits good dispersibility. Therefore, when tannic acid is used, the addition amount of the polyene polycarboxylic acids can be further reduced, and a metal colloid liquid having a small organic substance content can be obtained. When using the above various reducing agents,
The reduction reaction may be promoted by applying light or heat.

As a method for producing a solution containing metal colloid particles using the above-mentioned metal salt, polyene polycarboxylic acid and a reducing agent, for example, a solution of the above-mentioned metal salt is dissolved in pure water or the like to prepare a metal salt solution. A method of gradually dropping a metal salt solution into an aqueous solution in which a polyene polycarboxylic acid and a reducing agent are dissolved can be exemplified.

The method for preparing a mixed metal colloid liquid composed of a plurality of metals is not particularly limited. For example, when preparing a mixed metal colloid liquid composed of silver and another metal, the above method is used. A colloid solution and a metal colloid solution of another metal may be separately prepared and then mixed to form a mixed metal colloid solution, or a silver ion solution and another metal ion solution may be mixed and then reduced. .

The metal colloid solution of the present invention has good dispersibility of the metal colloid particles in a solution state and excellent storage stability, so that it is easy to handle. Since the film made of this metal colloid solution has excellent conductivity, It can be used in various technical fields. For example, electromagnetic wave shielding applications for cathode ray tubes, infrared shielding applications for building materials or automotive glass, antistatic applications for electronic devices and mobile phones, hot-wire applications for frosted glass, wiring materials for circuit boards and IC cards, electrodes and through-hole applications, It can be used for various uses in which conductive ink is used, such as microfabrication of semiconductors and coating for giving conductivity to resins. A conductive ink using the metal colloid liquid of the present invention is also one of the present invention.

The conductive ink can be produced by adding a film-forming aid to the metal colloid liquid of the present invention. Since the film-forming auxiliary is well compatible with the metal colloid particles, it is uniformly present between the metal colloid particles to uniformly disperse the metal colloid particles. Therefore, the conductive ink in a solution state has an effect of improving storage stability. When the conductive ink is applied to form a conductive film, the film-forming aid and the metal colloid particles have good affinity, and have an effect of increasing the strength by forming a strong film.
Since the metal colloid particles are uniformly dispersed in the coating, it is possible to produce a uniform coating with little variation in conductivity, and it is also possible to improve the adhesion to the substrate. That is, the above-mentioned film-forming auxiliary can provide an effective film strength with a small amount, and hardly impairs good conductivity.

The film-forming auxiliary is not particularly limited as long as it dissolves in an appropriate solvent and forms an excellent film with metal colloid particles. Examples thereof include polyurethane resins such as polyester resins and blocked isocyanates. Resins, polyacrylate resins, polyacrylamide resins, polyether resins, melamine resins, and the like can be given.

The solvent of the metal colloid solution of the present invention is water and / or
Alternatively, when the agent is a water-soluble agent, the film-forming auxiliary is preferably an aqueous resin. The aqueous resin is not particularly limited, for example, an aqueous polyurethane resin, a forced emulsion resin such as an aqueous polyester resin, a cellulose resin, an acrylate resin, a polyvinyl alcohol resin, a cellulose resin, an aqueous polyaniline resin,
Examples thereof include polyurethane resins such as blocked isocyanates, and melamine resins. These aqueous resins may be used alone or in combination of two or more.

As the aqueous resin, a polyurethane resin, a melamine resin, and a forced emulsion resin are preferably used. When the above-mentioned polyurethane resin or melamine resin is used, it is preferable to use a blocked isocyanate or melamine resin together with a polymer having an active hydrogen group.

Among the above-mentioned aqueous resins, a blocked isocyanate used in combination with a polymer having an active hydrogen group, a melamine resin used in combination with a polymer having an active hydrogen group, and a forced emulsion resin are more preferable. The aqueous resin composed of the resin as described above is extremely stable in a solution state, and a coating having good water resistance can be easily obtained by heating and drying and curing.

The above-mentioned blocked isocyanate is not particularly limited. For example, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like are blocked with oximes, alcohols, phenols, lactams and the like. And the like.

The melamine resin is not particularly restricted but includes, for example, alkyl group melamine, methylol group melamine, imino group melamine and the like.
The forced emulsion resin is not particularly limited, and examples thereof include an aqueous polyurethane resin and an aqueous polyester resin.

The polymer having an active hydrogen group is not particularly limited. For example, a polymer having a hydroxyl group such as polyoxytetramethylene glycol, polyoxypropylene glycol, polyoxyethylene glycol, or polyvinyl alcohol having a hydroxyl group; polyethylene Imin,
A polymer having an amino group such as polyacrylamide can be used.

The addition amount of the film-forming auxiliary is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the solid content in the metal colloid solution. If it exceeds 100 parts by weight,
Conductivity may deteriorate, and if less than 1 part by weight,
The effect of adding a film-forming aid is not seen. More preferably, it is 1 to 50 parts by weight.

The method for adding a film-forming aid to the metal colloid solution of the present invention is not particularly limited, and it may be added directly to the metal colloid solution, or by dissolving the film-forming aid in a water-soluble solvent or the like. A film assistant solution may be prepared and added to the metal colloid solution.

A conductive film can be produced by applying the above-mentioned conductive ink on a substrate and drying it. A conductive film using the conductive ink is also one of the present invention.

The substrate is not particularly limited, and may be, for example, a substrate made of alumina sintered body, phenol resin, glass epoxy resin, glass, or the like; a building material made of glass, resin, ceramic, or the like; The formed electronic device can be mentioned. The shape of the substrate is not particularly limited, and examples thereof include a plate shape and a film shape.

The method for applying the conductive ink on the substrate is not particularly limited, and examples thereof include dip, screen printing, spraying, bar coating, spin coating, and brushing. .

In producing the conductive film, a method for drying the conductive ink applied on the layer substrate includes the following.
Heating is preferred. By heating and baking the conductive ink, the conductivity of the obtained conductive coating can be further enhanced. Further, the heating method is not particularly limited,
For example, a dielectric heating method, a high-frequency heating method, or the like can be used. Since the conductive film is formed using the conductive ink of the present invention, the film strength is high.

[0060]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 (1) Synthesis of silver colloid solution 0.47 g of “CF7490” (manufactured by Fujisawa Pharmaceutical Co., Ltd.) and ferrous sulfate heptahydrate (special grade of reagent, manufactured by Wako Pure Chemical Industries, Ltd.) 3 .
2 g was dissolved in 90 mL of ion-exchanged water, adjusted to pH 7 with a sodium hydroxide aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd. and adjusted to a suitable concentration with reagent-ionized water), and then ion-exchanged water was added. To a total volume of 128 mL.
Next, while stirring with a magnetic stirrer at room temperature, 2 mL of an aqueous solution containing 1 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added dropwise to prepare a silver colloid solution of about 5 g / L. At this time, “CF7490” for 1 g of silver
The amount is 0.69 g. Note that “CF7490” is
This is a mixture in which the sodium salt of one compound and the sodium salt of the S2 compound are mixed at about 1: 1.

(2) Formation of Film A silver colloid solution was applied to a commercially available glass plate, allowed to dry naturally, and heated on a hot plate having a surface temperature of 250 ° C. for 5 minutes. By repeating this step, a silver film having a thickness of 1 μm was obtained.

(3) Evaluation method <Dispersibility> The silver colloid solution was well stirred and then transferred to a test tube. The solid content was evaluated as x when clearing and a clear supernatant was formed. <Volume Resistance> The volume resistance of the silver coating was measured using a portable double bridge 2769 manufactured by Yokogawa M & C.

(Example 2) A silver colloid solution was prepared in the same manner as in Example 1, except that 0.44 g of an ammonium salt of "CF7490" was used instead of "CF7490" (manufactured by Fujisawa Pharmaceutical Co., Ltd.). Then, the same evaluation as in Example 1 was performed. At this time, the amount of ammonium salt of “CF7490” per 1 g of silver is 0.69 g.

Example 3 A silver colloid solution was prepared in the same manner as in Example 1 except that 0.5 g of tannic acid (manufactured by Wako Pure Chemical Industries, Ltd., for chemistry) was used instead of ferrous sulfate heptahydrate. Created. Then, the same evaluation as in Example 1 was performed.

Comparative Example 1 A silver colloid solution was prepared in the same manner as in Example 1 except that 0.44 g of citric acid (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of “CF7490”. As in Example 1, decantation and desalting were not particularly performed. Then, the same evaluation as in Example 1 was performed. At this time, the citric acid amount per 1 g of silver is 0.69 g.

(Comparative Example 2) In place of "CF7490", 0.50 g of sodium citrate dihydrate (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) was used, and the pH was not adjusted with an aqueous sodium hydroxide solution. A silver colloid solution was prepared in the same manner as in Example 1 except for the above. As in Example 1, decantation and desalting were not particularly performed. Then, the same evaluation as in Example 1 was performed. At this time, the amount of sodium citrate per 1 g of silver is 0.69 g.

Comparative Example 3 A silver colloid liquid was prepared in the same manner as in Example 1 except that 4.0 g of Solsperse 27000 (manufactured by Abisia) which was a polymer pigment dispersant was used instead of “CF7490”. Then, the same evaluation as in Example 1 was performed. At this time, Solsperse 27000 per 1 g of silver ions is 6.3 g.

[0069]

[Table 1]

[0070]

According to the present invention, since it has the above-described structure, a metal colloid liquid which can obtain high dispersibility by a simple manufacturing method and still exhibit high conductivity can be provided.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihito Kakiuchi 3-4-7 Doshomachi, Chuo-ku, Osaka City Inside Fujisawa Pharmaceutical Co., Ltd. (72) Inventor Masafumi Takei 3-2-15 Meiwadori, Hyogo-ku, Kobe-shi Within Bando Chemical Co., Ltd. (72) Inventor J. Kamada 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical Co., Ltd. (72) Inventor Takuya Tomura 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical Co. In-house F term (reference) 4G065 AA04 AB11X AB38X BA07 BA20 CA01 DA06 EA02 4J039 AC01 AC02 AD13 BA06 BC29 BE29 CA05 DA02 EA24 EA44 FA02 FA04 FA07 GA15 GA16 GA34 4K017 AA08 BA02 BA05 DA07 EJ02 5G301 DA02 DA03 DA03 DA06 DA11

Claims (6)

[Claims] 1. A metal colloid liquid comprising at least one compound selected from the group consisting of polyene polycarboxylic acids, derivatives at carboxyl groups, and salts thereof. 2. The metal colloid solution according to claim 1, wherein the polyene polycarboxylic acid is a compound represented by the following general formula (1). Embedded image In the formula, n represents an integer of 0 to 5, and m represents an integer of 1 or 2. However, when n is 0, m is 1. 3. A metal colloid liquid comprising a solid content mainly composed of particles comprising a metal component and an organic component and a solvent, wherein the metal component is gold, silver, copper, platinum, palladium, rhodium. 3. The metal colloid liquid according to claim 1, comprising at least one metal selected from the group consisting of, ruthenium, iridium and osmium, and having an electric conductivity of 10 mS / cm or less. 4. The method according to claim 1, wherein the metal salt is reduced with a reducing agent.
4. The method for producing a metal colloid liquid according to 2 or 3, wherein the reducing agent is tannic acid. 5. A conductive ink comprising the metal colloid liquid according to claim 1, 2 or 3. 6. A conductive film comprising the conductive ink according to claim 5.