JP2007016301A - Colloidal metal solution and use of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a colloidal metal solution capable of giving electroconductive films being excellent in weather resistance and controlled in grain growth under a thermal load. <P>SOLUTION: The colloidal metal solution comprises silver and at least one element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc, and aluminum. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metal colloid solution capable of obtaining a film in which grain growth hardly occurs even when heated at a high temperature, and a conductive film produced using the metal colloid solution. Specifically, solar panel wiring, electrodes for flat panel displays, wiring for circuit boards or IC cards, through holes or circuits themselves, electromagnetic wave shielding applications for cathode ray tubes, infrared shielding applications for building materials or automobiles, electronic devices or mobile phones The present invention relates to a conductive material suitably used for antistatic application, heat ray application of frosted glass, coating application for imparting conductivity to a resin, and the like.

  Conventionally, for example, metal vacuum deposition, chemical vapor deposition, ion sputtering, and the like have been used as a method for producing a conductive film. However, since these methods require work in a vacuum system or a closed system, the operation is complicated, the mass productivity is poor, and a space for a large-scale apparatus is required, so that the investment is expensive. There were various problems (see, for example, Patent Document 1).

  There is also a method of forming a conductive film by plating. In this case, it is necessary to process a large amount of waste liquid, and there is a problem that material loss is large and extra cost is added, and addition to the environment is large. It was.

  On the other hand, when patterning a wiring is formed, a photolithography method is widely used. However, in this method, an extra step of masking a necessary portion of a conductive film formed on a substrate is necessary. Since a large amount of the photosensitive resin used, the removed metal film, and the waste liquid in which these are dissolved are discharged, there is a problem that the processing cost is high and the burden on the environment is large.

  In contrast to these methods, a method of obtaining a conductive film by applying a metal colloidal solution in which metal particles are dispersed in a dispersion medium and heating and firing the work requires a vacuum system or a closed system. Therefore, the conductive film can be manufactured at a low cost by a simple operation, and is attracting attention.

  As the metal to be used, gold is not practical from the viewpoint of cost, and copper is easily oxidized, so that it is substantially limited to silver. Although silver has the best electrical conductivity among metals, it has insufficient weather resistance against sulfur, oxygen, moisture, etc. in the atmosphere due to problems inherent in silver elements. As a result, the adhesion to the substrate is impaired, or the smoothness of the coating surface is impaired. Due to these problems, there is a fundamental problem that the reliability of bonding with other conductive materials is low, and application is difficult.

On the other hand, the technique which improves a weather resistance by adding a predetermined impurity to silver is disclosed (for example, refer patent document 2).
JP 2002-129259 A (published May 9, 2002) JP-A-57-186244 (published on November 16, 1982)

  According to the technique described in Patent Document 2, a technique regarding a silver-copper alloy is applicable. However, in the above conventional configuration, there is a problem that an effective film forming method for application is limited to ion sputtering or the like.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to simply add another metal element to a silver colloid solution that has a problem in weather resistance and causes grain growth under heat load. It is an object of the present invention to provide a metal colloid solution that can obtain a conductive film having excellent weather resistance and suppressing grain growth under heat load.

  The metal colloid solution according to the present invention includes silver and at least one element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc, and aluminum. Yes.

  In the metal colloid solution according to the present invention, the silver is preferably produced by a chemical reduction method.

  In the metal colloid solution according to the present invention, the Na content is preferably 0.01% by weight or less.

  The metal colloid solution according to the present invention is at least one element selected from the group consisting of silver produced by chemical reduction and gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc, and aluminum. It is characterized by including.

  In the metal colloid solution according to the present invention, an element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc and aluminum may exist in an ionic form.

  The metal colloid solution according to the present invention preferably uses a hydroxy acid having a COOH group and an OH group and having the number of groups of COOH ≧ OH or a salt thereof as a dispersant.

  The metal colloidal solution according to the present invention is subjected to thermogravimetric analysis on a solid obtained by drying at 30 ° C. or lower under a nitrogen atmosphere at a temperature rising temperature of 10 ° C./min up to 500 ° C. It is preferable that the weight loss is 10% by weight or less.

  The conductive film according to the present invention is obtained by drying any one of the above metal colloid solutions.

  In the conductive film according to the present invention, the metal element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc and aluminum is 0.001% by weight to the solid component 2% by weight is preferred.

  By using the present invention, it is possible to obtain a conductive film having excellent weather resistance and suppressing grain growth under a heat load.

  The present invention provides a metal colloid solution containing a first metal component and a second metal component. In the metal colloid solution according to the present invention, the first metal component is preferably silver synthesized by a chemical reduction method. In the metal colloid solution according to the present invention, the second metal component is at least one element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc, and aluminum. obtain. The metal colloid solution according to the present invention may be entirely produced by a chemical reduction method.

  Starting materials for obtaining silver as the first metal component include silver nitrate, silver sulfate, silver chloride, silver oxide, silver acetate, silver nitrite, silver chlorate, silver sulfide, etc., but in a suitable solvent It is not particularly limited as long as it is a soluble silver salt, and these 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 ultraviolet rays, an electron beam, or thermal energy. Examples of the reducing agent include amine compounds (eg, dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone, hydrazine, etc.); hydrogen compounds (eg, sodium borohydride, hydrogen iodide, hydrogen gas, etc.); oxides ( For example, carbon monoxide, sulfurous acid, etc .; low-valent metal salts (for example, ferrous sulfate, iron oxide, iron fumarate, iron lactate, iron oxalate, iron sulfide, tin acetate, tin chloride, tin diphosphate) Organic compounds (eg, sugars such as formaldehyde, hydroquinone, pyrogallol, tannin, tannic acid, salicylic acid, D-glucose, etc.), etc., but are dissolved in the dispersion medium. The metal salt is not particularly limited as long as it can reduce the metal salt. When the reducing agent is used, light and / or heat may be added to promote the reduction reaction.

  The second metal component may be in the form of metal particles, metal oxide particles or ions. In the case of the metal particle form, the metal particles synthesized in advance may be added as a second metal component to the silver colloid solution, or may be synthesized by being present and reduced simultaneously with the reduction of the silver particles. When reducing simultaneously, the reducing agent mentioned above can be applied. In the case of the metal oxide particle form, the metal oxide particles may be added to the silver colloid solution in advance. In the ionic form, metal ions may be added to the silver colloid solution as the second metal component or may be added when the silver particles are reduced. For example, as a reducing agent, a low-valent metal salt (for example, ferrous sulfate, iron oxide, iron fumarate, iron lactate, iron oxalate, iron sulfide, tin acetate, tin chloride, tin diphosphate, tin oxalate) Iron oxide (divalent or trivalent) or tin ion (divalent or tetravalent) may be added.

  Starting materials for the second metal component include gold salts (eg, chloroauric acid, potassium gold chloride, sodium gold chloride, etc.); platinum salts (eg, chloroplatinic acid, platinum chloride, platinum oxide, potassium chloroplatinate, etc.) Palladium salts (eg, palladium nitrate, palladium acetate, palladium chloride, palladium oxide, palladium sulfate, etc.); low-valent metal salts (eg, ferrous sulfate, iron oxide, iron fumarate, iron lactate, iron oxalate, Iron sulfide, tin acetate, tin chloride, tin diphosphate, tin oxalate, tin oxide, tin sulfate, etc.); gadolinium salts (eg, gallium sulfate, gallium chloride, gallium nitrate, etc.); nickel salts (eg, nickel acetate, Nickel chloride, nickel sulfate, nickel nitrate, etc.); zinc salts (eg, zinc bromide, zinc chloride, zinc iodide, zinc sulfate, etc.); aluminum Examples include metal salts such as potassium aluminum sulfate dihydrate, aluminum acetate, aluminum acetylacetonate, aluminum ammonium sulfate dihydrate, aluminum chloride, etc., as long as they are soluble in an appropriate solvent. It does not specifically limit, These may be used independently or 2 or more types may be used together.

  Although it does not specifically limit as a solvent used when preparing the metal colloid solution which concerns on this invention, Water and / or a water-soluble solvent are mentioned. When water and / or a water-soluble solvent is used as the solvent, the solvent odor that may be generated when the conductive ink produced using the metal colloid solution according to the present invention is dried or baked is not strong, There are few adverse effects.

  The average particle diameter of the metal particles in the metal colloid solution according to the present invention is preferably 1 to 400 nm, and more preferably 5 to 80 nm. Even if the particle diameter of the metal particles is less than 1 nm, the obtained conductive ink has good performance, but is not practical from the viewpoint of cost. When the particle diameter of the metal particles exceeds 400 nm, the dispersion stability of the metal colloid particles tends to change with time.

  The metal colloid solution according to the present invention contains a dispersant for dispersing the metal particles. Dispersing agents include organic acids (eg, citric acid, malic acid, tartaric acid, glycolic acid, etc.); ionic compounds (eg, trisodium citrate, tripotassium citrate, trilithium citrate, monopotassium citrate, citric acid, Disodium oxyhydrogen, potassium dihydrogen citrate, disodium malate, disodium tartrate, potassium tartrate, sodium potassium tartrate, potassium hydrogen tartrate, sodium hydrogen tartrate, sodium glycolate, etc.); surfactant (eg, todecylbenzene) Sodium sulfonate, sodium oleate, polyoxyethylene alkyl ether, perfluoroalkylethylene oxide adduct, etc.); high molecular substances (eg, gelatin, gum arabic, albumin, polyethyleneimine, polyvinyl cellulose, alkanes) Although such ols) are mentioned, as long as it exhibits with and dispersion effect dissolved in the dispersion medium is not particularly limited, they may be used singly in two or more may be used in combination.

  In the thermogravimetric analysis after the solid material obtained by drying the metal colloid solution according to the present invention at 30 ° C. was heated to 500 ° C. at 10 ° C./min in a nitrogen atmosphere. The weight change is preferably 10% by weight or less, and more preferably 5% by weight or less. When the weight change exceeds 10% by weight, the conductivity of the conductive film formed using the metal colloid solution according to the present invention is lowered.

  The dispersant is preferably a hydroxy acid having a COOH group and an OH group and having the number of groups of COOH ≧ OH or a salt thereof. Such dispersants include organic acids (eg, citric acid, malic acid, tartaric acid, glycolic acid, etc.); ionic compounds (eg, trisodium citrate, tripotassium citrate, trilithium citrate, monolithic citrate) Potassium, disodium hydrogen citrate, potassium dihydrogen citrate, disodium malate, disodium tartrate, potassium tartrate, sodium potassium tartrate, potassium hydrogen tartrate, sodium hydrogen tartrate, sodium glycolate, etc. Such dispersion If an agent is used, it is possible to obtain a conductive film that exhibits high conductivity and has sufficient weather resistance even at a low temperature of about 100 ° C., and the conductive film contains silver particles due to heat load at high temperature. Grain growth is suppressed.

  Furthermore, it is preferable to use a dispersant and / or a reducing agent that does not contain sodium. When a conductive film is used for an electrode of a flat panel display, it is required to be sodium-free in consideration of malfunction or adverse effects on other substrates. Therefore, when applied to such applications, the metal colloid solution according to the present invention preferably has a sodium content of 0.01% by weight or less.

  In addition, “grain growth” is a process in which the constituent particles are dispersed in a process in which the powder whose porosity between constituent particles has been reduced by heating is changed to a powder aggregate with significantly increased strength (ie, sintering). The phenomenon of coalescence and particle growth is contemplated. The “weather resistance” is generally intended to be resistance to exposure to the outdoors, that is, strength that can cope with environmental changes such as ultraviolet rays, snow, rain, and dryness.

The present invention also provides a conductive coating. The conductive film according to the present invention is obtained by drying the metal colloid solution. As used herein, the term “solid” is obtained by drying a metal colloid solution, and “conductive film” is intended to be a solid in the form of a film.
In the conductive film according to the present invention, the content of the metal element is preferably 0.001 to 5% by weight, more preferably 0.001 to 2% by weight, based on the solid component. When the amount of the metal element in the metal colloidal particles is less than 0.001% by weight with respect to the solid component, the problem of weather resistance and silver particle growth due to heat load at a high temperature cannot be solved. On the other hand, when the amount of the metal element in the metal colloid particles exceeds 5% by weight with respect to the solid component, the conductivity of the conductive film is lowered.

  In addition, what is necessary is just to set the film thickness of a conductive film suitably according to a use, for example, in the case of a wiring use, it may be several micrometers-several dozen micrometer.

  The present invention also provides a method for producing a metal colloid solution. The method for producing a metal colloid solution according to the present invention is characterized by using a metal salt, a dispersant and a reducing agent as described above. For example, a metal salt, a dispersant and a reducing agent are dissolved in a solvent, A method of mixing the solution while stirring can be mentioned. In the metal colloid solution obtained by such a method, a reducing agent residue or impurity ions are present in addition to the metal particles. These impurities are preferably removed because they adversely affect the dispersion stability of metal particles and / or the conductivity of the film. As a method for removing contaminants, for example, a step in which the colloidal metal solution is allowed to stand for a certain period of time, the resulting supernatant is removed, pure water is added, and the mixture is stirred and then allowed to stand again to remove the resulting supernatant. Examples include a repetitive method, a method of performing centrifugation instead of the above-mentioned standing, filtration using an ultrafiltration membrane or a reverse osmosis membrane, and desalting by an ion exchange column.

  The metal colloid solution according to the present invention may contain a known viscosity adjusting agent, thixotropic agent, surface tension adjusting agent, film-forming aid, and the like as long as the performance of the conductive film is not impaired. Examples of the viscosity modifier include emulsions (for example, polyester emulsion resins, acrylic emulsion resins, polyurethane emulsion resins, blocked isocyanates), polyester resins, polyacrylate resins, polyacrylamide resins, polyether resins. , Melamine-based resin, cellulose-based resin, acrylate-based resin, polyvinyl alcohol-based resin, aqueous polyanion-based resin and the like are not particularly limited, and these may be used alone or in combination of two or more.

  Examples of the thixotropic agent include viscosity minerals (for example, clay, bentonite, hectorite, etc.) and emulsions (for example, polyester emulsion resin, acrylic emulsion resin, polyurethane emulsion resin, blocked isocyanate, etc.), but are particularly limited. However, these may be used alone or in combination of two or more.

  The surface tension adjusting agent is not particularly limited as long as it has surface activity.

  Examples of the film forming aid include emulsions (eg, polyester emulsion resins, acrylic emulsion resins, polyurethane emulsion resins, blocked isocyanates), polyester resins, polyacrylate resins, polyacrylamide resins, and polyether resins. Resins, melamine-based resins, cellulose-based resins, acrylate-based resins, polyvinyl alcohol-based resins, aqueous polyanion-based resins and the like are exemplified, but they are not particularly limited, and these may be used alone or in combination of two or more. .

  As a base material to which the metal colloid solution according to the present invention is applied, for example, a substrate (for example, an alumina sintered body, a phenol resin, a glass epoxy resin, glass, etc.); a building material (for example, glass, resin, ceramic, etc.) An electronic device (for example, one having a surface formed of resin or ceramic), but is not limited thereto. Moreover, the shape of the said base material can be plate shape and film shape, for example.

  Examples of the method of applying the metal colloid solution according to the present invention on the substrate include, but are not limited to, dipping, screen printing, spray method, bar coating method, spin coating method, and brush method. .

  It should be noted that the specific embodiments made in the section of the best mode for carrying out the invention and the following examples are merely to clarify the technical contents of the present invention, and to such specific examples. It is not to be construed as limiting in any way whatsoever, and those skilled in the art can implement the invention within the spirit of the invention and the scope of the appended claims.

  Moreover, all the academic literatures and patent literatures described in this specification are incorporated herein by reference.

[Example 1]
A silver nitrate + chloroauric acid aqueous solution was prepared by dissolving 2.0 g of silver nitrate and 0.05 g of chloroauric acid in 100 ml of ion-exchanged water. Next, 1.7 g of 2-mercaptoethanol and 0.33 g of tannic acid were added to 100 ml of ion-exchanged water, and 10 ml of 1N sodium hydroxide aqueous solution was added dropwise while stirring this solution to adjust the pH, and silver nitrate + gold chloride. After adding the aqueous acid solution, the mixture was further stirred for 1 hour to obtain a metal colloid solution. The obtained metal colloid solution was filtered using an ultrafiltration membrane (manufactured by Advantech Toyo) having a molecular weight cut-off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml).

[Example 2]
A silver nitrate aqueous solution was prepared by dissolving 2.0 g of silver nitrate in 3 ml of ion-exchanged water. Next, 1.7 g of glycine and 1.5 g of tannic acid were added to 100 ml of ion-exchanged water, and while stirring this solution, 4 ml of 28% aqueous ammonia solution was added dropwise to adjust the pH. The mixture was stirred for a time to obtain a silver colloid solution. The obtained silver colloid solution was filtered using an ultrafiltration membrane (Advantech Toyo) having a molecular weight cut off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml). After filtration, 0.02 g of chloroauric acid was added to the silver colloid solution to obtain a metal colloid solution.

Example 3
A silver nitrate aqueous solution was prepared by dissolving 2.0 g of silver nitrate in 3 ml of ion-exchanged water. Next, 170 g of sodium citrate and 0.33 g of tannic acid were added to 100 ml of ion-exchanged water, and while stirring this solution, 10 ml of 1N aqueous sodium hydroxide solution was added dropwise to adjust the pH. The mixture was stirred for 1 hour to obtain a silver colloid solution. The obtained silver colloidal solution was filtered using an ultrafiltration membrane (manufactured by Advantech Toyo) having a molecular weight cut-off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml). After filtration, 0.01 g of iron sulfate was added to the silver colloid solution to obtain a metal colloid solution.

Example 4
A silver nitrate + chloroauric acid aqueous solution was prepared by dissolving 2.0 g of silver nitrate and 0.05 g of chloroauric acid in 100 ml of ion-exchanged water. Next, 1.7 g of glycine and 0.33 g of tannic acid were added to 100 ml of ion-exchanged water, 4 ml of 28% ammonia aqueous solution was added dropwise while stirring the solution, and silver nitrate + chloroauric acid aqueous solution was added. After that, the mixture was further stirred for 1 hour to obtain a metal colloid solution. The obtained metal colloid solution was filtered using an ultrafiltration membrane (manufactured by Advantech Toyo) having a molecular weight cut-off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml).

Example 5
A silver nitrate aqueous solution was prepared by dissolving 2.0 g of silver nitrate in 100 ml of ion-exchanged water. Next, 11 g of citric acid and 5 g of ferrous sulfate were added to 100 ml of ion-exchanged water, and while stirring this solution, 6 ml of 28% ammonia aqueous solution was added dropwise to adjust the pH. A metal colloid solution was obtained by stirring. The obtained metal colloid solution was filtered using an ultrafiltration membrane (manufactured by Advantech Toyo) having a molecular weight cut-off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml).

Example 6
Silver nitrate 2.0 g and 0.03 g of chloroplatinic acid were dissolved in 3 ml of ion-exchanged water to prepare a silver nitrate + chloroplatinic acid aqueous solution. Next, 17 g of sodium citrate and 0.33 g of tannic acid were added to 100 ml of ion-exchanged water, and while stirring this solution, 10 ml of 1N sodium hydroxide aqueous solution was added dropwise to adjust the pH, and silver nitrate + chloroplatinic acid aqueous solution was added. After the addition, the mixture was further stirred for 1 hour to obtain a metal colloid solution. The obtained metal colloid solution was filtered using an ultrafiltration membrane (manufactured by Advantech Toyo) having a molecular weight cut-off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml).

Example 7
Silver nitrate 2.0 g, chloroauric acid 0.02 g, and chloroplatinic acid 0.015 g were dissolved in 3 ml of ion-exchanged water to prepare a silver nitrate + chloroauric acid + chloroplatinic acid aqueous solution. Next, 1.7 g of 2-mercaptoethanol and 0.33 g of tannic acid were added to 100 ml of ion-exchanged water, and 10 ml of 1N sodium hydroxide aqueous solution was added dropwise while stirring this solution to adjust the pH, and silver nitrate + gold chloride. After adding acid + chloroplatinic acid aqueous solution, the mixture was further stirred for 1 hour to obtain a metal colloid solution. The obtained metal colloid solution was filtered using an ultrafiltration membrane (manufactured by Advantech Toyo) having a molecular weight cut-off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml).

Example 8
A silver nitrate aqueous solution was prepared by dissolving 2.0 g of silver nitrate in 3 ml of ion-exchanged water. Next, 17 g of sodium citrate and 0.33 g of tannic acid were added to 100 ml of ion-exchanged water, and 10 ml of 1N aqueous sodium hydroxide solution was added dropwise while stirring this solution. The mixture was stirred for 1 hour to obtain a metal colloid solution. The obtained metal colloid solution was filtered using an ultrafiltration membrane (manufactured by Advantech Toyo) having a molecular weight cut-off of 50,000 to remove impurity ions. Filtration was performed 20 times with 100 ml of ion-exchanged water (total 2000 ml). After filtration, 0.2 g of iron sulfate was added to the silver colloid solution to obtain a metal colloid solution.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that chloroauric acid was not added.

[Comparative Example 2]
Performed as in Example 2, except that no chloroauric acid was added.

[Evaluation]
Examples 1-7 and Comparative Examples 1-3 were evaluated according to the following.

(Electrical resistance)
The electrical resistance was measured using a DC precision measuring instrument (Double Bridge 2769-10 (manufactured by Yokogawa M & C Co.)). A metal colloid solution was applied onto a glass substrate with a brush and baked under conditions of 300 ° C. × 1 hour to form a film. The volume resistivity was converted from the distance between the measurement terminals and the film thickness. The conversion formula is shown below:
(Volume resistivity ρv) = (resistance value R) × (film width w) × (film thickness t) / (distance L between terminals)
Here, the film thickness was measured using a three-dimensional surface shape measuring device (manufactured by Nippon Beco Co., Ltd.).

(Reduced solid weight)
About the solid substance dried at 30 degrees C or less, the weight change at the time of heating up to 500 degreeC by 10 degree-C / min in nitrogen atmosphere was measured using the Seiko Instruments Inc. gravimetric analyzer. The weight reduction was calculated from the ratio of the reduction to the initial solid weight.

(Element determination)
The solid material dried at 30 ° C. or lower was acid-melted, and elements were quantified by ICP / MS method using SPQ-9000 manufactured by Seiko Denshi Kogyo. The amount of elements was expressed as a weight fraction with respect to the solid.

(High temperature resistance)
A film was formed on a glass substrate by spin coating using each metal colloid solution, and baked under conditions of 300 ° C. × 1 hour to form a conductive film. A part of the film was further baked at 300 ° C. for 1 hour, and the surface of the film was observed by SEM. The high temperature resistance of the film surface was evaluated by comparing the observation results.

  〔result〕

  When evaluating the high temperature resistance, it was determined that the state shown in FIG. 1 was “no change” and the change shown in FIG. 2 was “with grain growth”.

  Not only can it be used for solar panel wiring, flat panel display electrodes, circuit board or IC card wiring, through-holes, or the circuit itself, but also for cathode ray electromagnetic wave shielding applications, building materials or automotive infrared shielding applications, electronic devices or mobile phones It can also be applied to static electricity prevention applications for telephones, heat rays for frosted glass, and coating applications for imparting conductivity to resins.

As one embodiment of the present invention, the surface of the conductive film formed by baking at 300 ° C. for 1 hour (A) and the surface of the conductive film formed by baking at 300 ° C. for 1 hour (2 hours in total) ( B) shows a photograph of SEM observation. As comparative examples, the film surface (A) of the conductive film formed by baking at 300 ° C. for 1 hour and the film surface (B) of the conductive film formed by baking at 300 ° C. for 1 hour (2 hours in total) were SEM The observed photograph is shown.

Claims (7)

  A metal comprising silver produced by a chemical reduction method and at least one element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc, and aluminum Colloidal solution.   Silver produced by a chemical reduction method and at least one element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc, and aluminum, and having an Na content A colloidal metal solution characterized by being 0.01% by weight or less.   The metal colloid solution according to claim 1 or 2, wherein an element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc and aluminum exists in an ionic form. .   The metal colloid solution according to any one of claims 1 to 3, wherein a hydroxy acid or a salt thereof having a COOH group and an OH group and having a number of groups of COOH≥OH is used as a dispersant. .   The solid matter obtained by drying at 30 ° C. or lower was 10% by weight when subjected to thermogravimetric analysis under the condition of raising the temperature to 500 ° C. at a temperature raising temperature of 10 ° C./min in a nitrogen atmosphere. The metal colloid solution according to any one of claims 1 to 4, wherein the metal colloid solution is as follows.   A conductive film obtained by drying the metal colloid solution according to any one of claims 1 to 5. The metal element selected from the group consisting of gold, platinum, palladium, iron, tin, titanium, gallium, nickel, zinc and aluminum is 0.001% by weight to 2% by weight with respect to the solid component The conductive film according to claim 6.