KR101554580B1 - Silver-coated glass powder for electrical conduction, method for producing the same, and electrically conductive paste - Google Patents

Abstract

A silver-coated silver-coated glass powder having a silver content of 10% by mass or more is provided by adhering a surface treatment agent. The surface treatment agent is preferably at least one selected from benzotriazoles, fatty acids and salts thereof.

Description

The present invention relates to a silver-coated silver-coated glass powder and a method for producing the same, and a silver-coated glass powder for electrical conduction, a method for producing same, and an electrically conductive paste,

The present invention relates to a silver-coated glass powder (glass powder) for use in electronic parts such as an inner electrode of a multilayer capacitor, a conductor pattern of a circuit board, a solar cell, an electrode of a substrate for a plasma display panel, A method for producing the powder, and a conductive paste.

Description of the Background Art Conventionally, as a conductive paste used for electronic parts such as internal electrodes of a multilayer capacitor, a conductor pattern of a circuit board, a solar cell, an electrode of a substrate for a plasma display panel (PDP) A conductive paste prepared by mixing and adding to an organic beaker is used. Such conductive pastes are required to have properties of lower resistance and conductivity. As a result, many proposals have been made for employing materials having high conductivity represented by silver, gold, copper, or the like as a conductive component used in a conductive paste.

Of these, silver-coated glass powders coated with silver on glass powders are attracting attention (see JP-A-3-94078, JP-A-8-241049, and JP-A-2002-75252). This silver-coated glass powder ensures conductivity by using silver, and the amount of silver material used is small compared with that of silver, so that the cost of material cost can also be reduced.

However, when the silver-coated glass powder is used as it is in the conductive paste, conductivity can not be obtained and it is necessary to improve the conductivity of the paste by mixing with a conductive component such as copper powder (see Japanese Patent Application Laid-Open No. 9-296158) . In Comparative Example 2 and Table 1 of JP-A 9-296158, 100 parts by mass of silver-coated glass powder (particle size 38 μm or less), 10 parts by mass of an epoxy resin, 6 parts by mass of an amine- Mass part was mixed, but it became a nonwoven pulp without fluidity, and no paste was obtained. In addition, although heating and curing were attempted, the sheet state was not obtained, and the physical properties could not be measured. &Quot; and it is clear that the use of the silver-coated glass powder alone deteriorates the dispersibility and the conductivity.

In addition, when the silver-coated glass powder is fired, silver is sintered and the glass is softened, so that the particle shape of the silver-coated glass powder is not maintained. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 9-296158, The paste has only been examined, and application to a firing type conductive paste has not been mostly studied.

Therefore, in the case of using the conductive paste in conductive paste, it is expected to provide a conductive silver-coated glass powder having excellent conductivity and dispersibility and a conductive paste employing it.

The present invention provides a method for producing a silver-coated silver-coated glass powder and a silver-coated silver-coated glass powder for conductivity having excellent dispersibility and conductivity when used for a conductive paste, and a conductive paste containing the silver-coated silver- The purpose.

In order to solve the above-mentioned problems, the inventors of the present invention have conducted intensive studies and, as a result, have found that, in a method for producing silver coated glass powder by wet reduction method by silver coating by reducing silver particles in an aqueous reaction system containing silver ions , It is possible to efficiently prepare a coating silver-coated glass powder for conductivity having appropriate dispersibility and conductivity in a conductive paste by adding a surface treating agent before, during, or after a reducing coating of silver particles, a reducing coating or a reducing coating .

The present invention is based on the above knowledge by the present inventors, and means for solving the above problems are as follows. In other words,

 <1> A silver-coated silver powder coated with a surface treatment agent and having a silver content of 10% by mass or more.

<2> The surface-treating agent is at least one selected from the group consisting of benzotriazoles, fatty acids and salts thereof.

<3> The surface treating agent according to any one of <1> to <2>, wherein the surface treating agent is at least one selected from benzotriazole, stearic acid, oleic acid, lauric acid and salts thereof Coated glass powder.

&Lt; 4 > a sensitizing step of sensitizing glass powder with a tin solution; a silver-plating step of immersing the glass powder adhered on the surface of the tin into a silver solution to precipitate silver on the glass powder surface; And a silver coating step of adding silver complexing agent and a reducing agent to the silver solution containing the silver-containing glass powder to coat the silver powder on the surface of the glass powder after silver deposition, wherein the silver coating is performed before the silver coating, during the silver coating, A method for producing a coated silver glass powder, characterized in that a surface treatment agent is added to a process.

&Lt; 5 > The conductive paste according to any one of < 1 > to < 3 >

&Lt; 6 > The bulky conductive paste according to any one of &lt; 1 &gt; to &lt; 3 &gt;

According to the present invention, it is possible to solve the above-mentioned conventional problems and to achieve the above objects. In the case of using the conductive paste in conductive paste, a silver-coated silver powder for conductivity and an electroconductive silver- A method for producing the same, and a conductive paste containing the silver-coated glass powder for conductivity.

1 is a process diagram showing an example of a method for producing the silver-coated glass powder for conductivity according to the present invention.

(Coated glass powder for conductive use)

The conductive silver powder for coating of the present invention is formed by adhering a surface treatment agent and has a silver content of 10 mass% or more.

The conductive silver-coated glass powder is coated with silver on the surface of the glass powder while a surface treating agent is adhered thereto.

<Glass Powder (Glass Powder)>

The glass powder is not particularly limited and may be appropriately selected in accordance with the purpose. However, in view of environmental effects, a lead-free glass is preferable, and glass may be mixed with metal. Glass powder having a softening point lower than the temperature at which conductive paste is applied, dried and baked is preferable. The softening point of the glass powder differs depending on the kind of the conductive paste to be used, and therefore can not be defined as a whole. For example, it is preferably 600 DEG C or less.

As the glass powder, e.g., Bi ₂ O ₃ of a low softening point glass powder, low softening point glass frit, of a low softening point glass powder, the components of Bi ₂ O ₃ · ZnO to the ZnO as an ingredient of component Bi ₂ O ₃ · SiO ₂ · B ₂ O ₃ , a low-softening point glass powder containing Bi ₂ O ₃ · B ₂ O ₃ · ZnO as a component, and the like. In addition, the softening point is slightly higher, _{but, SiO 2 · B 2 O 3} · R 2 O or SiO ₂ · B may be used also glass powder as component a ₂ O ₃ · RO (however, R ₂ O is an alkali metal oxide, And RO represents an alkaline earth metal oxide).

The average particle diameter of the glass powder is preferably 100 占 퐉 or less, and more preferably 10 占 퐉 or less, more preferably 5 占 퐉 or less, in view of application to conductive use in which thinning proceeds.

Here, the average particle diameter of the glass powder can be measured by, for example, a laser diffraction type particle size distribution meter.

<Surface Treatment Agent>

The surface treatment agent is not particularly limited and may be appropriately selected depending on the purpose. Examples of the surface treatment agent include fatty acid, a fatty acid salt, a surfactant, an organometallic compound, a chelating agent, and a polymer dispersant.

Examples of the fatty acid include fatty acids such as propionic acid, caprylic acid, lauric acid, myristic acid, palmitin acid, stearic acid, behenic acid, acrylic acid, oleic acid, , Linoleic acid, and arachidonic acid.

Examples of the fatty acid salt include salts formed by the fatty acid and a metal. Examples of the metal include lithium, sodium, potassium, barium, magnesium, calcium, aluminum, iron, cobalt, , Tin, strontium, zirconium, silver, copper and the like.

Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and polyoxyethylene alkyl ether phosphate, cationic surfactants such as aliphatic quaternary ammonium salts, amphoteric surfactants such as imidazolinium betaine, poly Nonionic surfactants such as oxyethylene alkyl ethers and polyoxyethylene fatty acid esters.

Examples of the organic metal compound include acetylacetone tributoxy zirconium, magnesium citrate, diethyl zinc, dibutyl tin oxide, dimethyl zinc, tetra n-butoxy zirconium, triethyl indium, triethyl gallium, , Tetramethoxysilane, tetramethoxysilane, polymethoxysiloxane, monomethyltriisocyanate silane, silane coupling agent, titanate-based coupling agent, aluminum-based coupling agent, .

Examples of the chelating agent include imidazole, oxazole, thiazole, selenazole, pyrazole, isoxazole, isothiazole, 1H-1,2,3-triazole, 2H-1,2,3 Triazole, 1H-1,2,4-triazole, 4H-1,2,4-triazole, 1,2,3-oxadiazole, 1,2,4- 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3, 4-thiadiazole, 1H-1,2,3,4-tetrazole, 1,2,3,4-oxatriazole, 1,2,3,4-thiatriazole, 2H-1,2,3 , 4-tetrazole, 1,2,3,5-oxatriazole, 1,2,3,5-thiatriazole, indazole, benzoimidazole, benzotriazole, oxalic acid, succinic acid, But are not limited to, acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, glycolic acid, , Tartronic acid, hydroacrylic acid, mandelic acid, citric acid, ascorbic acid or And the like.

Examples of the polymeric dispersing agent include peptides, gelatin, collagen peptides, albumin, gum arabic, protarbic acid, and lysarubic acid.

The surface treatment agent may be used alone or in combination of two or more.

Among them, at least one member selected from benzotriazoles, fatty acids and salts thereof is preferable, and more preferable than at least one member selected from benzotriazole, oleic acid, stearic acid, lauric acid and salts thereof Do

The silver-coated glass powder to which the surface-treating agent is adhered can be obtained by appropriately selecting at least one of the surface-treating agents and adding it to the reaction system before or after the silver-reducing coating, or in the slurry state in the reducing coating, The affinity of the silver-coated glass powder to the conductive paste is improved, and the conductive film obtained by applying, drying and firing the conductive paste can be made low resistance.

The silver coating on the glass powder is not particularly limited and may be appropriately selected according to the purpose. However, silver may not completely cover the entire surface area of the glass powder, and silver coating may have a hole and a clearance, An intermittent silver coating with silver powder on the surface of the glass powder is also acceptable. When the silver paste is used for the conductive paste, the microscopic heterogeneity of the silver coating is not significantly affected by the silver coating state and the complicated interaction of the glass powder and the surface treatment agent.

(1) qualitative analysis of the surface treatment agent species according to Fourier transform infrared spectroscopy (FT-IR), (2) analysis of the silver content of the coated glass powder (3) is calculated from the absorbance of a solution obtained by mixing and heating the coated glass powder with hydrochloric acid, (3) a method in which the glass powder is dissolved in acetic acid, the solvent is extracted with chloroform or the like and analyzed by a carbon automatic analyzer or gas chromatography mass spectrometry And the like.

(Method for producing silver-coated silver-coated glass powder)

The method for producing a silver coating glass powder for conductive use according to the present invention includes a sensitization imparting step, a silver plating step and a silver coating step, and may further include other processes as required.

Here, FIG. 1 is a process diagram showing an example of a method for producing a silver-coated silver-coated glass powder according to the present invention.

As for the method for producing the silver coating glass powder for conductivity, a silver coating silver powder for conductivity can be imparted with good dispersibility and conductivity for the conductive paste by adding a surface treatment agent when electroless silver plating is performed on the glass powder .

<Sensitivity granting (Sensitizing) process>

In the step of imparting sensitivity, the glass powder is immersed in a tin chloride solution (SnCl ₂ ) to deposit tin on the surface of the glass powder, followed by filtration and washing the glass powder with pure water.

If excessive chlorine powder remains, the reaction is effected by reacting with silver in subsequent steps to generate silver chloride, etc., so that the cleaning is performed until the conductivity reaches 15 ms / m or less.

<Silver precipitation process>

The silver depositing step is a step of immersing the glass powder coated with tin on the surface obtained by the sensitivity imparting step with stirring in a silver solution to deposit silver on the glass powder. Since the amount of silver precipitated in the silver casting step is extremely small, a coating for further increasing silver in the following silver coating process is performed. Here, as the aqueous solution containing silver ions, an aqueous solution or slurry containing silver nitrate, a silver complex or a silver salt can be used, but silver nitrate is preferably used.

<Silver coating process>

The silver coating process is a process of adding silver complexing agent and a reducing agent to a liquid in which silver is deposited on the glass powder in the silver smelting process and coating silver on the glass powder.

In the silver coating process, the timing of addition of the surface treatment agent may be any time before addition of the reducing agent, during the addition of the reducing agent, and after the addition of the reducing agent. That is, the surface treatment agent is added at least either before the silver coating, during the silver coating, or after the silver coating. On the other hand, stirring and temperature adjustment are appropriately carried out.

The silver complexing agent can be produced, for example, by adding ammonia water, ammonium salt, chelate compound or the like to an aqueous solution of silver nitrate. Among them, an aqueous solution of ammine complex which can be obtained by adding ammonia water to an aqueous solution of silver nitrate is preferable. On the other hand, silver may be converted into an intermediate, or may be produced by adding sodium hydroxide, sodium chloride, sodium carbonate or the like to an aqueous solution of silver nitrate. In order to reduce the coordination number of ammonia in the amine complex to 2, 2 moles or more of ammonia is added per 1 mole of silver. If the added amount of ammonia is too large, the complex is excessively stabilized and the reduction becomes difficult to proceed. Therefore, the added amount of ammonia is preferably 8 mol or less per 1 mol of silver. On the other hand, if the addition amount of the reducing agent is adjusted to a large extent, silver-coated glass powder can be obtained even if the amount of ammonia added exceeds 8 moles.

The reducing agent is not particularly limited and may be appropriately selected depending on the purpose. Examples of the reducing agent include ascorbic acid, a sulfite, an alkanolamine, hydrogen peroxide, formic acid, ammonium formate, sodium formate, glyoxal, tartaric acid, sodium phosphate, boron hydride Sodium, hydroquinone, hydrazine, hydrazine compounds, pyrogallol, glucose, gallic acid, formalin, anhydrous sodium sulfite, rongalite and the like. These may be used singly or in combination of two or more. Of these, preferred are ascorbic acid, alkanolamine, sodium borohydride, hydroquinone, hydrazine and formalin, more preferably formalin and hydrazine, and hydrazine is particularly preferable.

The amount of the reducing agent to be added is preferably 1 equivalent or more with respect to silver in order to increase the reaction yield of silver. When a reducing agent having a weak reducing power is used, a reducing agent of 2 equivalents or more, for example, 10 equivalents to 20 equivalents of a reducing agent may be added to silver. Further, at the time of reduction, it is preferable to stir the reaction solution at a high speed so that the coating becomes uniform.

The addition amount of the surface treatment agent may be adjusted so that the silver powder content becomes a desired property between 0.05% by mass and 2% by mass with respect to the silver contained in the aqueous reaction system, and the ratio of the amount of each surface treatment agent Adjustment is good.

By filtering and cleaning the silver-containing slurry, it is possible to obtain a lumpy cake with little fluidity. The moisture in the cake may be replaced with a lower alcohol, a polyol or the like in order to accelerate the drying of the cake or to prevent agglomeration at the time of drying. The obtained silver-coated glass powder can be obtained by drying the obtained cake with a drier such as a forced circulation type air dryer, a vacuum drier or an air stream drier and pulverizing the same. Instead of crushing, silver halide grains may be added to an apparatus capable of mechanically fluidizing the grains, and the grains may mechanically collide with each other to smooth the surface irregularities and angular portions of the grains. In addition, the classification treatment may be performed after the solution is smoothed or the surface smoothing treatment is performed. On the other hand, drying, crushing and classifying may be carried out by using an integral device capable of drying, grinding and classifying (for example, dry meister, micron dryer, etc., manufactured by Hosokawa Micron Corporation).

It is preferable that the tap density of the coated glass powder is 1 g / cm ³ or more.

The tap density can be measured using, for example, a tap specific gravity measuring instrument (volume specific gravity measuring instrument, SS-DA-2 type, manufactured by Shibayama Scientific Co., Ltd.).

For the obtained conductive glass powder, the average particle diameter according to the laser diffraction method is preferably 100 占 퐉 or less, more preferably 0.01 to 100 占 퐉.

The average particle size can be measured using, for example, a microtrack particle size distribution analyzer (Haneywell - Nikkiso Co., Ltd., 9320 HRA (X-100)).

The BET specific surface area of the coating was obtained glass powder is conductive, it is preferably 0.1m ² / g~30m ² / g.

The BET specific surface area can be measured by BET 1-point method by nitrogen adsorption using, for example, Monosorb (product of Quanta Chrome).

The silver content in the silver coating glass powder for the conductive silver coating is 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more based on the whole silver-coated glass powder. If the silver content is less than 10% by mass, sufficient conductivity may not be obtained.

The silver content of the silver coating glass powder for conductivity may be a value calculated from a silver amount and a glass powder amount to be supplied to the reaction in the absence of silver ions remaining in the reaction solution, (ICP) luminescence analysis or the like by dissolving the glass component and removing the glass component by filtration.

(Conductive paste)

The conductive paste of the present invention contains the above-mentioned silver-coated glass powder for conductivity of the present invention, and contains a resin and, if necessary, other components.

The method for producing the conductive paste is not particularly limited and may be appropriately selected according to the purpose. For example, the conductive paste may be prepared by mixing the glass powder for conductivity and the resin.

The resin is not particularly limited and may be appropriately selected according to the purpose. Examples of the resin include epoxy resin, acrylic resin, polyester resin, polyimide resin, polyurethane resin, phenoxy resin, silicone resin and ethyl cellulose have. These may be used singly or in combination of two or more.

The content of the conductive silver-coated glass powder in the conductive paste is not particularly limited and may be appropriately selected depending on the purpose.

Examples of the other components include a dispersant and a viscosity adjusting agent.

The viscosity of the conductive paste is not particularly limited and may be appropriately selected according to the purpose. It is preferably 30 Pa · s to 1,000 Pa · s at 25 ° C. If the viscosity of the conductive paste is less than 30 Pa s, &quot; bleeding &quot; may occur during printing, and if the viscosity exceeds 1,000 Pa s, printing unevenness may occur.

The conductive paste of the present invention can form a conductive film having excellent conductivity even with a low silver content as compared with the conventional conductive paste. As a result, the conductive paste of the present invention can be suitably used as a conductive paste for forming electrodes, circuits, and electromagnetic wave shielding materials for various electronic components. On the other hand, the conductive glass powder for conductive use of the present invention can obtain a good conductivity with a silver content in a paste less than the conventional one. In addition, the conductive silver-coated glass powder of the present invention is suitably used for a small-sized conductive paste.

Examples

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Example 1)

173 g of ASF-1094 manufactured by Asahi Glass Co., Ltd. was prepared as a glass powder having an average particle size of 1.1 탆 and Bi ₂ O ₃揃 SiO ₂揃 B ₂ O ₃

First, this glass powder was immersed in an aqueous hydrochloric acid solution of tin chloride. After the dipping, the glass was filtered and washed to obtain a glass powder coated with Sn ^{2 +} (sensitivity imparting step).

The glass powder deposited with Sn ^{2 +} was placed in a reaction tank in which pure water was being stirred. The glass powder coated with Sn ^{2 +} was stirred and 600 g of silver nitrate aqueous solution containing 173 g of silver was added to the dispersed reaction tank to precipitate silver on the surface of the glass powder.

Subsequently, 400 g of 28% by mass aqueous ammonia and 40 g of 20% by mass aqueous sodium hydroxide solution were added to the reaction tank to obtain a silver ammine complex salt aqueous solution. The silver solution was prepared by adding 350 g of a hydrazine hydrate aqueous solution of 8 mass% at a temperature of 20 占 폚 of the liquid of the ammine complex salt aqueous solution, and silver particles were deposited on the glass powder to perform silver coating (silver coating step).

Silver was sufficiently deposited on the surface of the glass powder and after silver coating, 1.2 g of an ethanolic solution of oleic acid having a concentration of 20 mass% as a surface treatment agent was added. The obtained silver coated glass powder containing slurry was filtered and washed to obtain a cake. The obtained silver-coated glass powder had a silver content of 50 mass%.

Then, the obtained cake was dried in a vacuum dryer at 75 캜 for 10 hours to obtain a dried silver-coated glass powder. Followed by pulverization with a coffee grinder to obtain the silver-coated silver-coated glass powder of Example 1.

The taping density, the average particle size, the BET specific surface area and the ignition loss reduction value of the coated silver powder for conductive use of Example 1 were measured as described below. The results are shown in Table 1.

<Measurement of Tap Density>

15 g of the silver-coated glass powder was weighed using a tap specific gravity meter (volume specific gravity meter, SS-DA-2 type, manufactured by Shibayama Scientific Co., Ltd.) ), And tapping was performed 1,000 times with a drop of 20 mm to calculate the tap density = sample mass (15 g) / sample volume after tapping (cm ³ ).

&Lt; Measurement of average particle diameter &

The particle size distribution of the laser diffraction was measured by placing 0.3 g of the silver-coated glass powder for conductivity in 30 ml of isopropyl alcohol and dispersing for 5 minutes using an ultrasonic cleaner with an output of 50 W, and measuring the particle size distribution by using a microtrack particle size distribution analyzer (Haneywell- Manufactured by Nikkiso Co., Ltd., 9320 HRA (X-100)] was used to measure the average particle diameter of the silver-coated glass powder.

&Lt; Measurement of BET specific surface area &

The BET specific surface area of the coated glass powder for conducting was measured by the BET 1-point method by nitrogen adsorption using Monosorb (product of Quanta Chrome). On the other hand, in the measurement of the BET specific surface area, the degassing condition before measurement was set at 60 占 폚 for 10 minutes.

<Measurement of ignition loss value>

2 g of the silver powder sample is weighed (w1) into a magnetic crucible, and the glass powder is heat-treated at 800 DEG C until the weight becomes constant, cooled, and then measured again (w2) As shown in Equation (1).

(% By weight) = [(w1-w2) / w1] x 100 Formula 1

(Example 2)

With average particle size 1.6μm as the glass powder as the component _{Bi 2 O 3 · B 2 O} 3 · ZnO, Okuno carried out in the same manner as in Example 1 except for using 173g of a GF-3520 Chemical Industries Co., Ltd., carried out A silver-coated silver-coated glass powder of Example 2 was obtained. The obtained silver-coated glass powder had a silver content of 50 mass%.

The tapping density, the average particle size, the BET specific surface area, and the ignition loss value of the coated glass powder were measured in the same manner as in Example 1, The results are shown in Table 1.

(Example 3)

Except that 173 g of EMB-10 manufactured by Pottz-Baratini Co., Ltd. was used as a glass powder having a particle shape of SiO ₂ · B ₂ O ₃ · CaO · Al ₂ O ₃ having an average particle diameter of 4.5 μm , And the same procedure as in Example 1 was carried out to obtain the silver-coated silver powder for conductivity of Example 3. The obtained silver-coated glass powder had a silver content of 50 mass%.

The obtained coated glass powder for electric conduction was obtained in the same manner as in Example 1, and the tap density, the average particle diameter, the BET specific surface area and the ignition loss reduction value were measured. The results are shown in Table 1. Further, when the shape of the coated silver powder for conductivity was observed using a scanning electron microscope (JSM-6100, manufactured by Japan Electronics Co., Ltd.), it was confirmed that the shape of the rounded grain before silver coating was maintained.

(Example 4)

The procedure of Example 2 was repeated to obtain a silver-coated silver powder for conductivity of Example 4, except that 0.9 g of a 1,2,3,3-benzotriazole sodium aqueous solution having a concentration of 40% by mass as a surface treatment agent was used. The obtained silver-coated glass powder had a silver content of 50 mass%.

For the obtained conductive glass powder, the tap density, the average particle diameter, and the BET specific surface area were measured in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)

Except that 2.3 g of a stearic acid emulsion aqueous solution having a concentration of 15.5 mass% as a surface treatment agent was used in place of the aqueous silver nitrate solution. The obtained silver-coated glass powder had a silver content of 50 mass%.

For the obtained conductive glass powder, the tap density, the average particle diameter, and the BET specific surface area were measured in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)

Except that 1.2 g of an ethanol solution of lauric acid having a concentration of 20 mass% as a surface treatment agent was used in place of the silver coating glass powder of Example 6. The obtained silver-coated glass powder for Example 6 was obtained. The silver content in the powder was 50 mass%.

For the obtained conductive glass powder, the tap density, the average particle diameter, and the BET specific surface area were measured in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)

Except that 173 g of the Sn ^{2 +} -coated glass powder of Example 2 was used and the weight of the raw material used for precipitation and coating of silver was 3/7 times that of Example 2, Lt; / RTI &gt; of silver-coated silver powder was obtained. The obtained silver-coated glass powder had a silver content of 50 mass%.

For the obtained conductive glass powder, the tap density, the average particle diameter, and the BET specific surface area were measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)

The procedure of Example 2 was repeated except that 173 g of Sn ^{2 +} -coated glass powder of Example 2 was used and the weight of the raw material used for precipitation and coating of silver was 1/19 times, Lt; / RTI &gt; of silver-coated silver powder was obtained. The obtained silver-coated glass powder had a silver content of 5% by mass.

For the obtained conductive glass powder, the tap density, the average particle diameter, and the BET specific surface area were measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)

Example 2 was carried out in the same manner as in Example 2, except that the sensitivity imparting step was not carried out. As a result, the silver coating on the surface of the glass powder did not proceed sufficiently, and the silver ions remained dissolved in the reaction solution even after the completion of the reaction. If the silver ions remain dissolved in the reaction solution, the treatment process of the wastewater must be increased, which leads to an increase in cost.

From the results of Comparative Example 2, it can be seen that silver can not be coated on the surface of the glass powder without waste without being subjected to the sensitivity imparting step.

&Lt; Preparation of conductive paste &

A conductive paste was prepared by kneading the compositions of the examples 1 to 7 and the comparative example 1, which were obtained from the obtained silver-coated glass powder, the resin and the solvent, at the composition ratios described below. Specifically, a composition having the following composition was mixed in two times for 30 seconds using a propeller-less automatic airtight agitation deaerator (AR250, a product of Shin Kisa Co., Ltd.), and three rolls (product of Otto Herman Co., EXAKT80S) , And the roll gap was passed through from 100 mu m to 20 mu m to perform a kneading treatment to obtain conductive pastes, respectively. The conductive pastes of Examples 1 to 7 and Comparative Example 1 which were obtained were completely kneaded.

[Paste composition]

- Coating glass for conductive coating: 70.8 mass%

- resin (ethylcellulose, 100 cps, manufactured by Wako Pure Chemical Industries, Ltd.): 1.0% by mass

- Solvent (terpineol, manufactured by Wako Pure Chemical Industries, Ltd.): 28.2 mass%

(Comparative Example 3)

- Preparation of conductive paste -

Was coated in place of 70.8% by weight glass powder of Example 3 of the average particle diameter of 4.5μm with a _{SiO 2 · B 2 O 3 ·} CaO · Al 2 O 3 in the glass powder 35.4% by weight (70.8% by mass of a circle of ingredient Except that 35.4% by mass (half of 70.8% by mass) of silver halide (AG-2-1C, manufactured by Dowa Electronics Co., Ltd.) was used in place of the silver paste To prepare a conductive paste. The obtained conductive paste was completely kneaded.

&Lt; Formation and Evaluation of Conductive Film &

The above-mentioned conductive film made of each conductive paste was formed on a slide glass by screen printing. Screen printing conditions are as follows.

- Printing apparatus: MS-300 made by Murakami Corporation

- Printing conditions: Ski pressure 0.3 MPa

- The film was formed into a circuit having a width of 500 mu m and a length of 37.5 mm.

The obtained film was dried in an atmospheric circulation type dryer at 200 ° C for 20 minutes and then subjected to heat treatment at 580 ° C for 10 minutes in a box furnace to prepare the conductive film.

For each of the conductive films obtained, the film thickness and the volume resistivity were measured in the following manner. The results are shown in Table 2.

- thickness of the conductive film -

Each of the obtained conductive films was measured for the thickness of the conductive film by using a surface roughness machine (SE-30D, manufactured by Kosaka Laboratory Co., Ltd.) and measuring the step difference between the portion where the conductive film was not printed and the conductive film portion on the slide glass .

- Volume resistivity of conductive film -

Resistance of each conductive film obtained was measured using a digital multimeter (manufactured by ADVANTEST, R6551), and the resistance value at the position of the length (interval) of the conductive film was measured. The volume of the conductive film was determined from the size (film thickness, width, length) of the conductive film, and the specific resistance (volume resistivity) was obtained from the volume and the measured resistance value.

In Examples 1 to 7, the volume resistivity of 10 ^-4 Ω · cm or less can be achieved, whereas in Comparative Example 3, half of the inorganic components in the conductive paste are silver, the volume resistivity is 10 ^-3 Cm &lt; / RTI &gt; order.

From the above results, it was found that the conventionally provided conductive glass powder and conductive paste can be obtained.

Further, since the coating silver powder for conductive use of Example 3 has a circular particle shape, wiring formation can also be used as a photosensitive type conductive paste

According to Examples 1 to 7, a silver-coated silver-coated glass powder to be a raw material for a paste having excellent conductivity according to the present invention can be obtained.

In the embodiment, the tap density of the coating silver powder for conductivity is 1.5 g / cm &lt; ³ &gt; or more. The tap density is preferably 1 g / cm ³ or more, more preferably 1.5 g / cm ³ or more.

It can be seen that the average particle diameter of the coated glass powder for conduction is 1.4 μm to 5.5 μm, and more than 1 μm and less than 10 μm are more effective.

The conductive paste prepared using the coating silver powder for conductive use of the present invention can be suitably used as a conductive paste for forming electrodes and circuits of various electronic parts.

Claims (6)

A silver-coated silver-coated glass powder coated with silver powder,
And a surface treatment agent,
The content of silver is 10% by mass or more,
The glass powder is a glass powder for a conductive coating, characterized in that as component a _{Bi 2 O 3 · B 2 O} 3 · ZnO. The coated silver powder for conductivity according to claim 1, wherein the surface treating agent is at least one selected from benzotriazoles, fatty acids and salts thereof. The coated silver powder for conductivity according to claim 1, wherein the surface treating agent is at least one selected from benzotriazole, stearic acid, oleic acid, lauric acid and salts thereof. Susceptibility applying process to Shen palletizing by the glass powder for a _{Bi 2 O 3 · B 2 O} 3 · ZnO as a component in the solution and tin,
An electrodepositing step of immersing the glass powder deposited on the surface of the tin into a silver solution to deposit silver on the surface of the glass powder;
And a silver coating step of adding a silver complexing agent and a reducing agent to the silver solution containing the silver powder and coating the silver powder on the surface of the silver powder after silver deposit,
Wherein the surface treatment agent is added during at least one of the steps of: before coating silver, during coating silver, and after coating silver. A conductive paste comprising conductive silver powder according to claim 1. Characterized in that the conductive silver powder according to claim 1 contains a coated glass powder.

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