JP2015059223A - Organic gold compound, method of making the same, and conductive paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic gold compound capable of forming a gold film which has sheet resistance even through low-temperature firing at 250°C or lower by improving a disadvantage, i.e. conventional high-temperature firing of organic gold paste, and organic gold paste using the same.SOLUTION: An organic gold compound, represented by general formula (1) Au-S-(CH)-OH (where "n" is 2-6) having mercapto alcohols oriented to gold ions through reaction between gold salt and the mercapto alcohols in a solution containing a reductant in the presence of an inert gas is made into organic gold paste, which is screen-printed on a polyamide film and fired at 250°C so as to obtain a gold film having superior sheet resistance.

Description

  The present invention relates to an organic gold compound, a method for producing the same, and a conductive paste. More specifically, the present invention relates to a conductive paste for forming a gold film conductive circuit on an electronic component such as a polyamide film, a printed wiring board, a ceramic IC package, or a wafer. The present invention relates to an organic gold compound used, a method for producing the same, and a conductive paste.

Conventionally, an organic gold paste is known as a conductive paste for forming a conductive pattern such as a film electrode on a substrate.
A typical application of such an organic gold paste is the production of electrodes for thermal printer heads used as printer heads for facsimiles and the like.

Prior art related to this application includes gold compounds such as α-pinene, α-terpineol, gold isocaptane, or sulfide gold, gold abetienoate, gold neodecanoate, gold 2-ethylhexanoate, gold naphthenate. After using one or two or more of the above, an organic gold paste containing a rhodium compound, a bismuth compound, a chromium compound, a lead compound, a silicon compound, an organic resin, an organic solvent, and screen printing on a ceramic substrate, It is known that a gold thin film is obtained by baking at 800 to 850 ° C. (for example, Patent Document 1).
Since such a conventional organic gold paste is fired at a high temperature of 800 ° C. or higher, only a material that can withstand high temperatures such as ceramics can be used as a substrate. It was impossible to apply to functional resin films such as polyamide films and substrates known as heat resistant films. Moreover, since the thing corresponding to high temperature is used as a baking furnace, there also existed a problem which requires energy cost.

JP-A-5-144318

  The present invention provides an organic gold compound capable of forming a gold film having a sheet resistance even by low-temperature baking at 250 ° C. or less by improving the difficulty of high-temperature baking of such a conventional organic gold paste, and an organic gold paste using the same The purpose is to provide.

  In order to solve the above problems, the present inventor has intensively studied an organic gold compound capable of obtaining a gold film having a sheet resistance by baking at a low temperature. As a result, gold salt and mercaptoalcohol in the presence of an inert gas are obtained. The organic gold compound obtained by reacting the reaction solution in an aqueous solution containing a reducing agent at a temperature of 0 ° C. to 90 ° C. after completion of the reaction, concentrating and crystallizing the reaction solution is an organic gold paste, and is screen printed on a polyamide film. As a result of firing at 250 ° C., the inventors have found that a gold film having excellent sheet resistance can be obtained, and reached the present invention.

That is, this invention makes the following content the summary of the invention.
(1) It is represented by the general formula (1) formed by reacting a gold salt and a mercapto alcohol in an aqueous solution containing a reducing agent in the presence of an inert gas to coordinate the mercapto alcohol with a gold ion. Organic gold compounds.
General formula (1)
(Chemical formula 1)
_{Au-S- (CH 2) n} -OH (1)

(Wherein n is 2-6)

(2) The organic gold compound according to claim 1, wherein the gold salt is one or more selected from gold hydroxide, barium goldate, and thunder gold.
(3) The organogold compound according to claim 1 or 2, wherein the mercapto alcohol is 2-mercaptoethanol or an analogue thereof.
(4) Any one of claims 1 to 3 represented by the general formula (1), wherein the reducing agent is one or more selected from hydrazine salts, sodium sulfite, oxalic acid, formic acid, glucoses and amino alcohols. An organic gold compound as described above.
(5) It is characterized by reacting gold salt and mercapto alcohol in an aqueous solution containing a reducing agent in the presence of an inert gas at a temperature of 0 ° C. to 90 ° C., and after completion of the reaction, the reaction solution is concentrated and crystallized. The manufacturing method of the organic gold compound in any one of Claims 1-4.
(6) A conductive paste comprising one or more of a synthetic resin binder, glass frit, and alumina blended in the organic gold compound according to any one of claims 1, 2, 3, and 4.

  According to the provision of the organic gold compound of the present invention, the production method and the conductive paste, the organic gold compound represented by the general formula (1) is blended into an organic resin binder to form a paste, and this is formed into a ceramic substrate and a soda lime substrate. In addition to printing on a polyimide film and baking at a low temperature of 250 ° C. or lower, a gold pattern with good adhesion to the substrate and a low sheet resistance value can be formed, so that it has applicability to a plastic film. In addition, since the organic gold compound provided in the present invention is a non-cyanide gold compound, it is possible to produce a gold plating solution with less environmental impact by using a gold salt material for gold plating. Since it is a material that can be a source, its industrial utility value is great.

Hereinafter, the organic gold compound of the present invention, the production method thereof, and the conductive paste using the same will be described in detail.
The method for producing an organic gold compound according to the present invention is a method for producing an organic gold compound that is excellent in dispersibility and conductive film-forming properties used in conductive pastes such as electrode formation of electronic components. The organic gold compound obtained by this production method is used.

1 Method for Producing Organogold Compound The method for producing an organogold compound of the present invention comprises a gold salt selected from gold hydroxide, barium goldate, thunder metal, and mercapto alcohols such as 2-mercaptoethanol and 3-hydroxy. Propyl mercaptan, 4-hydroxybutyl mercaptan and the like are reacted at a temperature of 0 ° C. to 90 ° C. in an aqueous solution containing a reducing agent in the presence of an inert gas such as nitrogen gas and argon gas. After completion of the reaction, in the presence of an inert gas, the reaction solution is cooled to 30 ° C. or lower to precipitate crystals and dried at 120 ° C. or lower to obtain an organic gold compound crystal powder.

As the reducing agent, one or more selected from hydrazine salts, sodium sulfite, oxalic acid, formic acid, glucoses and amino alcohols are used.
The obtained organic gold compound crystal powder is preferably a powder having an average particle size of 0.1 μm to 2 μm by a pulverization method such as an impact method or a grinding method in order to obtain a powder suitable for a conductive paste.

  As a result of component analysis of crystals obtained by synthesizing mercaptoalcohols with 2-mercaptoethanol by the above method, Au 71.7% (calculated value: 71.9%), S11.6% almost agreeing with the theoretical value. (Calculated value: 11.7%). Therefore, it was confirmed that the organogold compound of the present invention was a crystal represented by the general formula (1).

2 Conductive Paste The conductive paste of the present invention contains the organic gold compound of the present invention, an organic resin binder, and an organic solvent as main components.
As an organic resin binder, what is used for the conventional conductive paste can be used. For example, cellulose polymers such as ethyl cellulose and hydroxyethyl cellulose, acrylic resins such as polybutyl methacrylate, polymethyl methacrylate, and polyethyl methacrylate, epoxy resins, polyurethane resins, phenol resins, alkyd resins, polyvinyl butyral, etc. The organic gold compound of the present invention is mixed with an organic resin binder dissolved in a solvent such as butyl carbitol, butyl carbitol acetate, or terpineol, and a surfactant, plasticizer, dispersant, etc. are added as necessary. It can be obtained by kneading and dispersing into a paste using this roll mill or other kneader.

Hereinafter, the present invention will be described specifically by way of examples.

(1) Production of organic gold compound 50.0 g of chloroauric acid is dissolved in 500 ml of pure water, and 5% sodium hydrogen carbonate is added to this and stirred until the pH is 9.0. The precipitated gold hydroxide is filtered off and washed with pure water.
Next, after the gold hydroxide after washing is dispersed in 800 ml of pure water, the liquid temperature is set to 60 ° C. by heating and stirring while bubbling nitrogen gas. Leave for 1 hour.
Then, a small amount (part) of 48.2 g of sodium sulfite is slowly added to this suspension solution. While confirming the state of the reaction, a small amount (part) of 14.2 g of 2-mercaptoethanol is slowly added. Add the remaining sodium sulfite while confirming the reaction. While the bubbling of nitrogen gas is continued as it is, the temperature of the reaction solution is kept at 60 to 65 ° C. and aged for 3 hours.
Further, the remaining 2-mercaptoethanol is gradually added to the reaction solution. After completion of the addition of 2-mercaptoethanol, the temperature of the reaction solution is kept at 80 ° C., and bubbling of nitrogen gas is continued for 5 hours as it is, followed by ripening. At this time, the solvent should not be reduced in the manner of reflux.
The reaction solution after completion of ripening is cooled to 30 ° C. or lower while continuing bubbling of nitrogen gas and stirring as it is to precipitate crystals. Next, the crystals were filtered, washed with ethanol, and dried at 80 ° C. to obtain 24.3 g of pale yellow powdery crystals. (Yield: 73.0%)
(2) Preparation of conductive paste 20 parts by weight of the organic gold compound obtained in Example 1, 20 parts by weight of an organic resin dinder (ethyl cellulose 6% by weight terpineol solution) and 10 parts by weight of terpineol were pre-kneaded, and then three of these were mixed. A conductive paste was prepared by kneading with a roll mill.
Using this conductive paste, screen printing on a 325 mesh screen on a polyimide film of 50 mm x 60 mm x 0.1 mm, followed by drying at 120 ° C for 15 minutes with a dryer, peak temperature at 250 ° C in a conveyor furnace, peak firing time Baking was performed for 10 minutes from the inlet to the outlet over 60 minutes, and a gold thin film pattern of 2 mm × 20 mm was provided on the polyimide film.
The results of measuring the sheet resistance value of the gold thin film thus obtained are shown in Table 1.

(1) Production of organic gold compound 50.0 g of chloroauric acid is dissolved in 500 ml of pure water, and 10% aqueous ammonia is added and stirred therein until the pH reaches 10.0. The deposited thunder gold is separated by filtration and washed with pure water.
Next, after the washed thunder gold is dispersed in 800 ml of pure water, the liquid temperature is set to 60 ° C. by heating and stirring while bubbling nitrogen gas. Leave for 1 hour.
Then, a small amount (part) of 48.2 g of sodium sulfite is slowly added to this suspension solution. While confirming the state of the reaction, a small amount (part) of 14.2 g of 2-mercaptoethanol is slowly added. Add the remaining sodium sulfite while confirming the reaction. While the bubbling of nitrogen gas is continued as it is, the temperature of the reaction solution is kept at 60 to 65 ° C. and aged for 3 hours.
Further, the remaining 2-mercaptoethanol is gradually added to the reaction solution. After completion of the addition of 2-mercaptoethanol, the temperature of the reaction solution is kept at 80 ° C., and bubbling of nitrogen gas is continued for 5 hours as it is, followed by ripening. At this time, the solvent should not be reduced in the manner of reflux.
The reaction solution after completion of ripening is cooled to 30 ° C. or lower while continuing bubbling of nitrogen gas and stirring as it is to precipitate crystals. Next, the crystals were filtered, washed with ethanol, and dried at 80 ° C. to obtain 18.8 g of a pale yellow powdery crystal. (Yield: 56.5%)
(2) Preparation of conductive paste 20 parts by weight of the organic gold compound obtained in Example 2, 20 parts by weight of an organic resin binder (ethylcellulose 6% by weight terpineol solution) and 10 parts by weight of terpineol were pre-kneaded, and then three of these were mixed. A conductive paste was prepared by kneading with a roll mill.
Using this conductive paste, screen printing on a 325 mesh screen on a polyimide film of 50 mm x 60 mm x 0.1 mm, followed by drying at 120 ° C for 15 minutes with a dryer, peak temperature at 250 ° C in a conveyor furnace, peak firing time Baking was performed for 10 minutes from the inlet to the outlet over 60 minutes, and a gold thin film pattern of 2 mm × 20 mm was provided on the polyimide film. The results of measuring the sheet resistance value of the gold thin film thus obtained are shown in Table 1.

(1) Production of organic gold compound 50.0 g of chloroauric acid is dissolved in 500 ml of pure water, and 114.8 g of barium hydroxide octahydrate is added and stirred therein. The precipitated barium metal oxide is filtered off and washed with pure water.
Next, after the washed barium aurate is dispersed in 800 ml of pure water, the liquid temperature is set to 60 ° C. by heating and stirring while bubbling nitrogen gas. Leave for 1 hour.
Then, a small amount (part) of 48.2 g of sodium sulfite is slowly added to this suspension solution. While confirming the state of the reaction, a small amount (part) of 14.2 g of 2-mercaptoethanol is slowly added. Add the remaining sodium sulfite while confirming the reaction. While the bubbling of nitrogen gas is continued as it is, the temperature of the reaction solution is kept at 60 to 65 ° C. and aged for 3 hours.
Further, the remaining 2-mercaptoethanol is gradually added to the reaction solution. After completion of the addition of 2-mercaptoethanol, the temperature of the reaction solution is kept at 80 ° C., and bubbling of nitrogen gas is continued for 5 hours as it is, followed by ripening. At this time, the solvent should not be reduced in the manner of reflux.
The reaction solution after completion of ripening is cooled to 30 ° C. or lower while continuing bubbling of nitrogen gas and stirring as it is to precipitate crystals. Next, the crystals were filtered, washed with ethanol, and dried at 80 ° C. to obtain 14.3 g of a pale yellow powdery crystal. (Yield: 43.0%)
(2) Preparation of conductive paste 20 parts by weight of the organic gold compound obtained in Example 3, 20 parts by weight of an organic resin binder (ethylcellulose 6% by weight terpineol solution) and 10 parts by weight of terpineol were pre-kneaded, and then three of these were mixed. A conductive paste was prepared by kneading with a roll mill.
Using this conductive paste, screen printing on a 325 mesh screen on a polyimide film of 50 mm x 60 mm x 0.1 mm, followed by drying at 120 ° C for 15 minutes with a dryer, peak temperature at 250 ° C in a conveyor furnace, peak firing time Baking was performed for 10 minutes from the inlet to the outlet over 60 minutes, and a gold thin film pattern of 2 mm × 20 mm was provided on the polyimide film. The results of measuring the sheet resistance value of the gold thin film thus obtained are shown in Table 1.

Comparative example

Preparation of conductive paste 20 parts by weight of α-pinene sulfide gold compound, 20 parts by weight of an organic resin binder (6% by weight of ethylcellulose terpineol solution) and 10 parts by weight of terpineol were pre-kneaded and then kneaded by a three-roll mill. An adhesive paste was prepared.
Using this conductive paste, screen printing on a 325 mesh screen on a polyimide film of 50 mm x 60 mm x 0.1 mm, followed by drying at 120 ° C for 15 minutes with a dryer, peak temperature at 250 ° C in a conveyor furnace, peak firing time Baking was performed for 10 minutes from the inlet to the outlet over 60 minutes, and a gold thin film pattern of 2 mm × 20 mm was provided on the polyimide film. The results of measuring the sheet resistance value of the gold thin film thus obtained are shown in Table 1.

Table 1 confirms that the thin film formed from the paste of the organic gold compound of the present invention has a very good conductivity because it is a dense film even when subjected to low-temperature firing on a polyimide film. It was.
On the other hand, the film formed of the organic gold paste of the comparative example was not good in sinterability at low temperatures, and therefore the conductivity could not be measured.
In the organometallic compound of the present invention, metal Au precipitation is effective even in low-temperature firing, as is apparent from the differential thermal analysis results as shown in FIG.
From the measurement result of TG-DTA, it can be confirmed from the TG curve that the decomposition started from around 190 ° C., and it became metal Au at a stretch. Furthermore, the reaction is terminated at around 230 ° C., indicating that metal Au can be deposited by low-temperature firing.
Moreover, it can confirm that it is an endothermic reaction when it becomes metal Au from a DTA curve. Usually, the organic component burns and often exhibits an exothermic reaction, but this thermal decomposition mechanism is not the deposition of metal Au due to the combustion of the ligand, but the distribution by the electron transfer reaction between the gold and the ligand. Ligand elimination-metal Au precipitation.

3 is differential thermal analysis data of the organic gold compound of Example 1.

Claims (6)

An organic gold represented by the general formula (1) obtained by reacting a gold salt with a mercapto alcohol in an aqueous solution containing a reducing agent in the presence of an inert gas to coordinate the mercapto alcohol with a gold ion. Compound.
General formula (1)
(Chemical formula 1)
_{Au-S- (CH 2) n} -OH (1)

(Wherein n is 2-6)
  The organic gold compound according to claim 1, wherein the gold salt is one or more selected from gold hydroxide, barium goldate, and thunder gold.   The organogold compound according to claim 1 or 2, wherein the mercapto alcohol is 2-mercaptoethanol or an analogue thereof.   The reducing agent according to any one of claims 1 to 3, represented by the general formula (1), which is one or more selected from hydrazine-based salts, sodium sulfite, oxalic acid, formic acid, glucoses, and amino alcohols. Organic gold compounds.   A gold salt and a mercapto alcohol are reacted in an aqueous solution containing a reducing agent in the presence of an inert gas at a temperature of 0 ° C to 90 ° C, and after completion of the reaction, the reaction solution is concentrated and crystallized. Item 5. A method for producing an organic gold compound according to any one of Items 1 to 4. 5. A conductive paste comprising one or more of a synthetic resin binder, glass frit, and alumina blended in the organic gold compound according to claim 1, 2, 3 or 4.