JP2002245854A - Colloidal solution of metal, and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a colloidal solution of metal having high dispersion obtained by a simple manufacturing method, and showing high conductivity, and to provide a manufacturing method of the same. SOLUTION: The colloidal solution of metal is made to contain a compound having at least one amino group and one carboxyl group.

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 metal compounds, dispersants and reducing agents used for preparing metal colloid liquids. 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. The mixture was appropriately mixed and reacted to obtain a colloidal solution of silver fine particles, and 0.4% was added to the solid portion obtained by sedimentation and separation.
Remove the iron by adding a molar sodium nitrate solution,
Further centrifugation at 3000 G gravity to obtain silver solids,
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, the solid content is separated, desalting treatment is performed by dialysis, and a silver colloid solution also used for a coating material for forming a transparent conductive film, or 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 required.

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 hardly aggregates is 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 polymer-based pigment dispersant is used to enhance the property, there is a problem that conductivity is sacrificed.

[0009]

DISCLOSURE OF THE INVENTION In view of the above, the present invention provides high dispersibility by a simple production method,
An object of the present invention is to provide a metal colloid liquid exhibiting high conductivity and a method for producing the same.

[0010]

According to the present invention, there is provided a metal colloid solution containing a compound having at least one amino group and at least one carboxyl group. 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,
It has been found that, without special control of the atmosphere, temperature, and stirring speed, a high dispersibility can be obtained by a simple production method, and that a metal colloid liquid exhibiting high conductivity can be obtained. Reached.

The metal colloid solution of the present invention is characterized by containing a compound having at least one amino group and one carboxyl group (hereinafter referred to as compound A). The compound A can function as a dispersant in the metal colloid solution.

JP-A-10-68661, JP-A-10-6861
Citric acid or citrate exemplified as a dispersant in many prior art documents such as JP-A No. 0-110123 and JP-A-2000-87122 is a low-molecular-weight dispersant, and has one hydroxyl group and a carboxyl group. It has three groups.

A citrate having three carboxyl groups has been often used as a dispersing agent since it can disperse metal colloidal particles satisfactorily by the electric repulsion of ionized carboxyl groups. However, citrate has a low adsorption efficiency on the metal colloid particle surface, so it is necessary to add a large amount of citrate in order to enhance dispersibility. A large amount of the agent will remain in the metal colloid solution. 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, the compound A can function as a dispersant. However, since the amino group has a higher adsorptivity to the surface of the metal colloid particles than the hydroxyl group, the compound A is more efficient. The metal colloid particles can be adsorbed on the surface of the metal colloid particles, and the metal colloid particles having higher dispersibility can be obtained by adding a small amount. In addition, they found that the number of carboxyl groups required for dispersing the metal colloid particles can be reduced,
It has been found that a compound having an amino group and a carboxyl group can exhibit sufficient dispersibility if it has at least one carboxyl group in the molecule. For this reason, it has been found that since the amount of the dispersing agent to be added can be extremely small, a metal colloid liquid having a small content of organic substances affecting conductivity can be obtained without performing centrifugation or ultrafiltration.

The compound A is not particularly limited, but is preferably a compound having a small molecular weight or a compound having a plurality of carboxyl groups. Can be mentioned.

The carboxyl group of compound A is preferably in the form of a salt. By using a salt, the dispersion stability due to the repulsion of carboxylate ions can be increased. In addition, the solubility in water increases. The salt is not particularly limited, for example, sodium salt, potassium salt,
Lithium salts, ammonium salts and the like can be mentioned.

The amount of the compound A is 1 g of metal.
Is preferably 0.05 to 5 g. 0.0
If the amount is less than 5 g, the effect of compound A cannot be exerted and 5 g
When the amount exceeds the above range, the amount exceeds the saturation amount of the compound A, so that even if the added amount is increased, no further effect can be obtained, which departs from the gist of the present invention that the amount of the dispersant can be extremely reduced.

The metal colloid liquid of the present invention comprises a solid containing particles composed of a metal component and an organic component (hereinafter referred to as metal colloid particles) as main components, and a solvent. In the metal colloid solution of the present invention, the metal component of the metal colloid particles is gold, silver, copper, platinum, palladium, rhodium,
Ruthenium, iridium, osmium and the like can be mentioned. Among them, silver, copper, platinum and palladium are more preferred. These metals may be used alone,
Two or more kinds may be used in combination.

The metal colloid liquid of the present invention is preferably a mixed metal colloid liquid of silver and another metal. 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. The other metals are gold, copper, platinum, palladium, rhodium, ruthenium, iridium, and osmium. Among them, copper, platinum and palladium are preferred.

When the mixed colloid liquid as described above is used,
As for the ratio of silver to the other metal in the metal colloid liquid, the weight ratio of silver to the other metal is 99: 1 to 30: 7.
It is preferably 0. If the proportion of silver exceeds 99% by weight, it becomes 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-metal colloid solution may be reduced.
More preferably, it is 95: 5 to 40:60, and still more preferably, it is 90:10 to 60:40.

The metal content of the metal colloid solution of the present invention is preferably 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.

In the present invention, the organic components include:
The compound A and the like can be mentioned. In the metal colloid solution of the present invention, the compound A can function as a dispersant. However, 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 solution 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. When the amount is less than 1% by weight, the storage stability of the obtained metal colloid solution tends to be deteriorated. When the amount exceeds 30% by weight, the conductivity of the conductive film formed using the obtained metal colloid solution tends to deteriorate. There is. More preferably, it is 2 to 20% by weight.

The solvent used for 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 as the solvent, the solvent odor does not become strong at the time of drying or baking of the conductive ink produced from the metal colloid liquid, and the environment is not adversely affected.

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 made 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. The high-concentration metal colloid solution may be adjusted to an optimum concentration for use later using an appropriate solvent.

In the metal colloid liquid of the present invention, it is preferable that 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 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.

If the solid content is less than 1% by weight, the content of the metal is too small. Therefore, when forming a conductive film using the obtained metal colloid solution, it is difficult to obtain a necessary thickness. Repeated application is required, which is industrially disadvantageous. 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 liquid 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 is determined by thermogravimetric analysis from 100 to 5
An aqueous metal colloid solution having a heating loss to 00 ° C. of 1 to 25% by weight has excellent 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. In addition, 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 compound A may be prepared by any method. It may be reduced by a method.

The above-mentioned metal salt is not particularly limited as long as it can be dissolved in an appropriate solvent and can be reduced by any means. For example, 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. Of these, tannic acid is preferred. When tannic acid is used as the reducing agent, the obtained metal colloid exhibits good dispersibility. Therefore, when tannic acid is used, the amount of the compound A to be added 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, light or heat may be further added to promote the reduction reaction.

A method for producing a solution containing metal colloid particles using the above metal salt, compound A and a reducing agent includes the following:
For example, there is a method in which the metal salt is dissolved in pure water or the like to prepare a metal salt solution, and the metal salt solution is gradually dropped into an aqueous solution in which the compound A and the reducing agent are dissolved.

In the solution containing the metal colloid particles obtained as described above, in addition to the metal colloid particles, a residue of the reducing agent and the compound A are present. ing. Since the liquid in such a state has a high electric conductivity, coagulation of the metal colloid particles occurs, and the liquid tends to precipitate. By washing the solution containing the metal colloid particles to remove excess electrolyte, the conductivity becomes 10 mS / c.
m or less can be obtained.

As the washing method, for example, the liquid containing the obtained metal colloid particles is allowed to stand for a certain period of time, the resulting supernatant is removed, pure water is added, and the mixture is stirred again.
Furthermore, a method of repeating the process of removing the supernatant liquid generated by standing for a certain period of times several times, a method of performing centrifugation instead of the above-mentioned standing, a method of desalting with an ultrafiltration device, an ion exchange device, and the like are given. be able to. Above all, a desalting method is preferable. In addition, the conductivity is set to 10 mS by desalination or the like.
/ Cm or less may be appropriately concentrated.

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 method described above is used. A silver 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. Good.

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 a 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, 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 holes, semiconductor microfabrication applications, conductive materials for resins Can be used in various applications where a conductive ink is used, such as a coating application for imparting an ink. Conductive ink using the metal colloid liquid of the present invention is also,
This is one of the present invention.

It is preferable that the conductive ink is obtained 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 thus have an effect of increasing the strength by forming a strong film. Since the film is uniformly dispersed in the film, a uniform film having little variation in conductivity can be manufactured, and the adhesion to the substrate can be improved. That is, the film-forming auxiliary can provide effective film strength with a small amount,
Moreover, good conductivity is hardly impaired.

The above-mentioned 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, aqueous polyurethane resin, forced emulsion resin such as aqueous polyester resin, cellulose resin, acrylate resin, polyvinyl alcohol resin, cellulose resin, 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.

Of these, polyurethane resins, melamine resins and forced emulsion resins are preferred as the aqueous resin. 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 aqueous resins, more preferred are blocked isocyanates used in combination with a polymer having an active hydrogen group, melamine resins used in combination with a polymer having an active hydrogen group, and forced emulsion resins. 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 and polyvinyl alcohol having a hydroxyl group; polyethylene Imin,
A polymer having an amino group such as polyacrylamide can be used.

The amount of the film-forming aid to be added is preferably 1 to 100 parts by weight based on 100 parts by weight of the solids 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 of 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 conductive ink on a substrate and drying. 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. Examples of the shape of the substrate include a plate shape and a film shape.

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

In producing the above-mentioned 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, the film strength is high.

[0057]

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 0.44 g of glycine (reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) and ferrous sulfate heptahydrate (reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) )
After dissolving 3.2 g in 90 mL of ion-exchanged water and adjusting the pH to 7 with an aqueous sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., a special grade reagent adjusted to an appropriate concentration with ion-exchanged water), ion exchange was performed. Water was added to bring the total volume to 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 liquid having a metal content of about 5 g / L. At this time, the amount of glycine per 1 g of silver is 0.69 g.

(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 if it settled and a clear supernatant was formed, and if not, it was evaluated as ○. <Volume Resistance> The volume resistance of the silver coating was measured using a portable double bridge 2769 manufactured by Yokogawa M & C.

(Example 2) Serine (reagent grade, L-serine, manufactured by Wako Pure Chemical Industries, Ltd.) 0.44 instead of glycine
A silver colloid solution was prepared in the same manner as in Example 1 except that g was used, and the same evaluation as in Example 1 was performed. At this time, 1g of silver
Is 0.69 g, and the metal content of the silver colloid solution is about 5 g / L.

(Example 3) A silver colloid solution was prepared in the same manner as in Example 1 except that 0.44 g of glutamic acid (special grade, L-glutamic acid, manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of glycine. The same evaluation as in Example 1 was performed. At this time, the amount of serine per 1 g of silver was 0.69 g,
The metal content of the silver colloid is about 5 g / L.

Example 4 The silver colloid solution of Example 1 was
Put into a Centricut U-10 manufactured by Kurashiki Spinning Co., Ltd., and ultrafiltrate with a centrifuge at 3000 rpm for 30 minutes to finally adjust the volume to 8 mL to prepare a silver colloid liquid having a metal content of about 80 g / L. The same evaluation as in Example 1 was performed.

Example 5 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. It was fabricated and evaluated in the same manner as in Example 1. At this time, the metal content of the silver colloid liquid is about 5 g / L.

Comparative Example 1 A silver colloid liquid 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 glycine. 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) Sodium citrate dihydrate instead of glycine (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.)
Using 0.50 g, p with aqueous sodium hydroxide solution
A silver colloid solution was prepared in the same manner as in Example 1 except that H adjustment was not performed. 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 glycine. Then, the same evaluation as in Example 1 was performed. At this time, Solsperse 270 for 1 g of silver ion
00 becomes 6.3 g. Table 1 shows the above results.

[0068]

[Table 1]

[0069]

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 exhibits high conductivity can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B22F 9/24 B22F 9/24 F 5G301 H01B 13/00 H01B 13/00 Z // C09D 11/10 C09D 11 / 10 (72) Inventor Takuya Tonomura 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical F-term (reference) 4D075 CA03 CA13 CA22 CA25 DA06 DB13 DB14 DB46 DB61 DC01 DC18 DC21 EA06 EA12 EB01 EB07 EB19 EB22 EB32. DA06 DA11 DA12 DA42 DA51 DA53 DA59 DD02

Claims (6)

[Claims] 1. A metal colloid liquid containing a compound having at least one amino group and at least one carboxyl group. 2. The metal colloid solution according to claim 1, wherein the carboxyl group is a salt. 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.