JP4967223B2 - Water-based electrode ink and method for producing the same - Google Patents

Description

  The present invention relates to a water-based electrode ink used for electrode formation and a method for producing the same.

  Electrode patterns such as electronic parts can be formed over a wide range, and many conductive pastes based on metal powders are used in organic solvents. Printing methods using these conductive pastes include screen printing and gravure. Printing and offset gravure printing are frequently used.

  However, these electronic components have been downsized, electrode formation of electronic components has become finer, and higher precision is required. To meet these requirements, screen printing, gravure printing and offset gravure printing are required. Instead of printing or the like, a printing method using an inkjet printing technique has been proposed. This ink-jet printing method does not require a screen plate, gravure plate, etc., and it is possible to form a fine electrode pattern by directly discharging electrode ink from the ink-jet head by controlling the electronic data of the electrode pattern through personal computer control, etc. It has the advantage that it can be used in a production system corresponding to shortening and small quantities of various products.

  In addition, in the case of using a thin ceramic green sheet such as a multilayer ceramic capacitor, the non-contact inkjet printing method prints an electrode pattern without damaging the thin ceramic green sheet. Is possible.

  Recently, a technique relating to water-based inks in place of organic solvent-based inks that affect the environment has been disclosed.

For example, Patent Literature 1 and Patent Literature 2 are known as prior literature information on these.
JP-A-11-102934 International Publication No. 99/38176 Pamphlet

  However, in the conventional configuration, the electrode ink for ink jet printing in which low viscosity is indispensable has a problem that it is very difficult to stably disperse metal particles having a high specific gravity with a high content ratio without being settled. Was. In particular, there are problems that aggregates in the electrode ink, nozzle clogging of the ink jet head due to precipitates, wrinkling of the electrode pattern, and the like occur.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a water-based electrode ink capable of stably printing an electrode pattern and a method for producing the same.

  In order to solve the above-mentioned conventional problems, the present invention contains a metal powder content of 25 to 40% by weight with respect to the total weight of the water-based electrode ink, and has an average molecular weight of at least two kinds selected from water-soluble resins. 3 to 6 parts by weight of a different water-soluble resin with respect to 100 parts by weight of the metal powder, 1.5 to 1.9 times the weight of the water-based plasticizer with respect to the water-soluble resin, and the remainder comprising water In the water-based electrode ink, one water-soluble resin has an average molecular weight of 5,000 to 10,000, and the other water-soluble resin has an average molecular weight of 150,000 to 360,000.

  The aqueous electrode ink of the present invention and the method for producing the same can increase the stability of dispersion due to sedimentation, so that an electrode pattern can be stably printed on an object to be printed constituting an electronic component using an inkjet printing method. An aqueous electrode ink and a method for producing the same can be provided.

(Embodiment 1)
Hereinafter, the water-based electrode ink and the manufacturing method thereof according to Embodiment 1 of the present invention will be described.

  As the metal powder in Embodiment 1 of the present invention, nickel powder having an average particle diameter of 0.2 μm is used, and 5 parts by weight of a water-soluble resin as shown in (Table 1) with respect to 100 parts by weight of the nickel powder is aqueous. As a plasticizer, 9 parts by weight of glycerin, which is 1.8 times the weight ratio of water-soluble resin, and 13 parts by weight of water are blended, and nickel powder is mixed while kneading these materials with three rolls. Mixed and dispersed.

  Then, the aqueous electrode ink shown in (Table 1) was produced by mixing and dispersing with a high-speed disper mill while gradually adding 158 parts by weight of water. In order to evaluate the viscosity and dispersibility of the water-based electrode ink, the filterability with a 5 μm filter and the state of sedimentation and separation of metal particles after 5 hours were observed in a state of standing in a test tube. The viscosity was measured at 25 ° C. using a torsional vibration viscometer (Viscomate VM-1G). The measurement evaluation results are shown in (Table 1).

  From the results of (Table 1), relatively high molecular weight resins have better filter filterability and sedimentation stability, but in order to achieve a viscosity of 35 mP · sec or less desired for inks for ink jet printing alone. Must be diluted significantly. The electrode pattern to be printed requires a predetermined electrode thickness, and in order to secure this thickness, it is necessary to increase the content of the metal particles in the electrode ink. Dilution is inconvenient. On the other hand, the water-based electrode ink having the ink composition of the present invention can achieve both low viscosity and stability of sedimentation separation, and the water-based electrode inks of Examples 1 to 5 have good dispersibility. It can be seen that there is no clogging in terms of filterability, and there is little sedimentation and separation of metal particles despite the low ink viscosity. This is because a water-soluble resin having a large average molecular weight adheres to the surface of the metal powder and behaves as a single powder particle in a state containing this water-soluble resin having a large average molecular weight. As a result, the apparent specific gravity in the solvent is reduced, so that the dispersion stability due to sedimentation is considered to increase. Furthermore, by adding a water-soluble resin having a small average molecular weight, the viscosity of 35 mP · sec or less necessary for inkjet printing can be realized by exerting an effect of reducing the viscosity of the electrode ink.

  As described above, a water-based electrode ink containing a water-soluble resin in which a water-soluble resin having an average molecular weight of 5,000 to 10,000 and a water-soluble resin having a molecular weight of 150,000 to 360,000 is combined with a metal powder, and further comprising a water-based plasticizer and water. By doing so, it is possible to stabilize the dispersion of the metal powder and to realize a low-viscosity aqueous electrode ink that is indispensable for inkjet printing.

  Further, by using an ammonium salt of an isobutylene / maleic anhydride copolymer (for example, Kuraray water-soluble resin: isoban) or polyvinylpyrrolidone, a water-based electrode ink having better dispersion stability can be realized and water-soluble. A coating film insoluble in water can be formed by causing a crosslinking reaction by heating in combination with a plasticizer, alcohols and amines.

  Moreover, the adhesiveness with respect to moderate to-be-printed material can be improved by adding a water-system plasticizer in 1.5 to 1.9 times by weight ratio with respect to water-soluble resin.

  Specific examples of water-soluble resins used in these metal powders include cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, ethyl-hydroxyethylethylcellulose, polyvinyl alcohol resins, water-soluble butyral resins, polyvinylpyrrolidone resins, water-soluble resins. Can be selected from water-soluble acrylic copolymer resins, proteins such as gelatin and casein, saccharides such as starch and glucose, among which nonionic and cationic water-soluble resins are more desirable.

  Next, the content of the metal powder was examined. The composition of the basic aqueous electrode ink was based on Example 3, and the ink characteristics were evaluated by changing only the metal content as shown in (Table 2). The evaluation results at that time are shown in (Table 2).

  From the results of (Table 2), the content of the metal powder is preferably 25 to 40% by weight. Here, in the formation of the electrode pattern, the electrode thickness is required to keep the conductor resistance of the electrode low. When the content of the metal powder is reduced, it is difficult to make the electrode thickness sufficiently practical. On the other hand, when the content of the metal powder is too large, the metal powder is liable to settle and separate, and there is a problem in stability in continuous printability.

  Next, the kind of metal powder and the average particle diameter were examined. A metal powder as shown in (Table 3) is prepared, and a water-soluble resin having the same composition as in Example 3 is prepared by the same method as described above, and the aqueous plasticizer is made of glycerin / triethanolamine = 1/1. In addition, the added amount is added in a weight ratio of 1.8 times with respect to the water-soluble resin, and further, water is blended at a ratio of 13 parts by weight, and various metal powders are kneaded with these materials by three rolls. Were dispersed.

  Then, each aqueous electrode ink as shown in (Table 3) was produced by mixing and disperse | distributing with a high-speed disper mill, adding 158 weight part of water gradually. In order to evaluate the viscosity and dispersibility of this water-based electrode ink, the settling separation state of the metal particles after 5 hours and the printability in the ink jet printing method were evaluated in a state of being left in a test tube. The results are shown in (Table 3).

  From the results of (Table 3), the metal powder was used as an electrode material, a metal having a high conductivity, such as gold, silver, platinum, palladium and a silver / palladium alloy, and a noble metal such as copper, nickel and a base metal thereof. Thus, an aqueous electrode ink suitable for ink jet printing can be obtained.

  The base metal material has a slightly higher conductor resistance, but a refractory metal material such as tungsten or molybdenum that can be fired at a high temperature can also be used for a multilayer substrate such as a ceramic package.

  Further, as a base metal alloy material, a Ni—Cr alloy or the like can be used as a water-based electrode ink by a similar method.

  In addition, by setting the average particle size of the metal powder to 0.05 to 0.4 μm, it is possible to realize a water-based electrode ink suitable for printability that does not cause clogging or curling.

  Next, the amount of water-soluble resin added was examined.

  Using nickel powder having an average particle size of 0.2 μm, a water-soluble resin is added to 100 parts by weight of the nickel powder so as to have a composition as shown in (Table 4), and glycerin is used as a water-based plasticizer. 9 parts by weight, which is 1.8 times the weight ratio, and 13 parts by weight of water were blended, and the nickel powder was mixed and dispersed while kneading these materials with three rolls.

  Then, the aqueous electrode ink shown in (Table 4) was produced by mixing and dispersing with a high-speed disper mill while gradually adding 158 parts by weight of water. In order to evaluate the viscosity and dispersibility of the water-based electrode ink, the filterability with a 5 μm filter and the state of sedimentation and separation of metal particles after 5 hours were observed in a state of standing in a test tube. Viscosity was evaluated for ink characteristics using a viscometer. The evaluation results at that time are shown in (Table 4).

  From the results of (Table 4), the addition amount of the water-soluble resin is preferably in the range of 3 to 6 parts by weight with respect to 100 parts by weight of the metal powder.

  Next, the water plasticizer was examined. In Table 1, glycerin was used as this water-based plasticizer, but here, water-based plasticizers shown in (Table 5) and their addition amounts were examined. The electrode ink was produced in the same manner as described above, and the filterability and sedimentation stability of these aqueous electrode inks were evaluated.

Water-soluble resins generally become very hard. For example, when manufacturing a multilayer ceramic capacitor, this water-based plasticizer is mixed when the electrode pattern is printed on a ceramic green sheet and then laminated by thermocompression. Otherwise, adhesion may not be obtained. Thus, it is important to select a water-based plasticizer for the laminateability of the ceramic green sheet. This ceramic green sheet is laminated on a ceramic green sheet mainly composed of barium titanate (dielectric layer is about 4 to 5 μm and about 2 to 3 μm after firing). A pattern was printed, and the produced electrode-formed ceramic green sheet was used for heat transfer at 90 ° C. to 85 kg / cm ² to laminate 100 sheets. And lamination | stacking adhesiveness was confirmed by cut | disconnecting them and observing the cut surface.

  The evaluation results are shown in (Table 5).

  From the results of (Table 5), if the addition amount of the water-based plasticizer is less than 1.5 times that of the water-soluble resin, adhesiveness does not appear, and if it is more than 1.9 times, the electrode pattern is formed on the dielectric green sheet. After printing, sticking between the ceramic green sheets was observed when wound up.

  Among aqueous plasticizers, triethanolamine exhibits alkalinity in an aqueous solution, and therefore can be used for controlling the pH during ink production, which will be described later, and more effective in stabilizing the dispersion of metal particles. In addition, the water-based plasticizer can be selected from ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols, triethanolamine, and the like.

(Embodiment 2)
Hereinafter, the water-based electrode ink and the manufacturing method thereof according to Embodiment 2 of the present invention will be described.

Based on the aqueous electrode ink composition of Example 1, a predetermined amount of barium titanate was added to 100 parts by weight of the aqueous electrode ink of Example 1 as shown in (Table 6). A water-based electrode ink for ink-jet printing was prepared by converting into an ink. A predetermined internal electrode pattern was printed by an ink jet printing method on a ceramic green sheet mainly composed of barium titanate (about 2 to 3 μm after firing with a dielectric layer of about 4 to 5 μm). Lamination was performed by thermal transfer at 90 ° C. to 85 kg / cm ² using the ceramic green sheet with the internal electrodes formed as described above. Note that a dielectric layer (invalid layer) having a thickness of about 200 μm was formed on the top and bottom during the production of the laminate. Next, after lamination, the green chip was manufactured by cutting and dividing into pieces.

  Next, this green sheet is removed from the binder. The heat treatment conditions for the binder removal were performed in a hot air circulation oven having a condition of holding at 350 ° C. for 4 hours in air, and then left to cool. Next, the green chip after the binder removal was fired in an atmosphere using a tubular furnace. This firing atmosphere uses a certain amount of nitrogen gas as a carrier, and an atmosphere using hydrogen and water vapor so that the oxygen concentration at the firing temperature is about one digit reduction side with respect to the equilibrium oxygen partial pressure of Ni. Adjusted by control.

  Next, the external electrode of the fired multilayer chip was formed by polishing a sintered body of the multilayer chip with a centrifugal barrel, and then applying a commercially available Cu paste to both end surfaces of the multilayer chip and baking at 900 ° C. .

  Next, in order to improve mountability, a plating electrode as an external electrode is formed. In this plating process, Ni plating was performed as a base treatment, and further, solder plating was performed to improve solder wettability.

  The multilayer ceramic capacitor produced as described above was measured for cracks, capacitance, and tan δ after firing with a commercially available LCR meter.

  The temperature characteristics were determined in accordance with JIS-C6429-1989 by 1 KHz, signal voltage 1 Vrms. The maximum capacity change rate (with reference to the capacity of 20 ° C.) within the standard temperature range (−25 ° C. to 85 ° C.) was determined. The evaluation results of these multilayer ceramic capacitors are shown in (Table 6).

  From the results of (Table 6), the multilayer ceramic capacitor obtained by printing the internal electrode pattern using the aqueous electrode inks of Examples 27 to 29 can suppress cracks due to firing, and the electrical characteristics of the multilayer ceramic capacitor are also good. Results were obtained.

  In this way, when the internal electrode pattern printed on the ceramic green sheet is laminated and sintered, the metal powder alone is fired between the electrode layer and the dielectric layer at the timing of shrinkage when the metal powder is sintered. In the case where cracks are easily generated, the effect of preventing cracks due to sintering can be exhibited by adopting such a configuration.

  Further, the addition amount of the barium titanate powder is preferably 10 to 25 parts by weight. When the amount added is small, the effect of preventing cracks and the like is reduced. When the amount is too large, the electrical characteristics of the multilayer ceramic capacitor are deteriorated.

(Embodiment 3)
Hereinafter, the water-based electrode ink according to Embodiment 3 of the present invention will be described.

  Here again, as in the second embodiment, a predetermined amount of glass as shown in (Table 7) is used, based on the aqueous electrode ink composition of Example 1 and using silver powder with an average particle size of 0.3 μm as the metal powder (Table 7). Powder (average particle size: 0.07 μm) and manganese oxide (average particle size: 0.25 μm) were added to prepare an aqueous electrode ink for inkjet printing in the same manner as described above.

Next, a predetermined wiring pattern was printed on an alumina substrate using these water-based electrode inks by an ink jet printing method. They were then baked at 870 ° C. in a N ₂ stream. The peel strength and resistance value of the wiring pattern thus produced were measured. The evaluation results are shown in (Table 7).

  From the results of (Table 7), in the water-based electrode ink to which glass powder or manganese oxide is added, since the glass powder or manganese oxide increases the adhesion to the alumina substrate, an electrode pattern having excellent peel strength can be formed. . Moreover, as for the addition amount, 0.5-10 weight part of glass powder is preferable, and 0.5-5 weight part of manganese oxide is preferable. When the amount added is small, the adhesion is lowered, and when the amount is too large, the electrical characteristics as an electrode deteriorate. Furthermore, glass powder and manganese oxide may be mixed and used.

(Embodiment 4)
Hereinafter, the manufacturing method of the water-based electrode ink in Embodiment 4 of this invention is demonstrated.

  The aqueous electrode ink of Example 3 was prepared according to the following procedure.

  First, as a first step, nickel metal powder, resin A (average molecular weight 150,000) and water were mixed and dispersed for 1 hour by a planetary mixer.

  As the next step, resin B (average molecular weight of 50,000), glycerin and water were added, mixed and dispersed with a planetary mixer for 30 minutes, and further dispersed with three rolls. Then, 158 weight part of water was added and diluted, stirring with a high-speed disper, and the water-system electrode ink for inkjets was produced (Example 36).

  Next, the aqueous electrode ink having the composition of Example 28 was prepared by changing as follows.

  As a first step, nickel metal powder (average particle size 0.2 μm): resin A (average molecular weight 150,000) and 9.5 parts by weight of water were mixed for 0.5 hour by a planetary mixer. In order to estimate the pH in this state, 10 g of the nickel powder was added to 100 g of distilled water, and the pH of the supernatant was measured. As a result, pH = 6.5.

  Next, as a second step, barium titanate powder: 20 parts by weight, resin B: 4 parts by weight, and water: 0.5 parts by weight were added and mixed for 30 minutes. In order to estimate the pH in this state, the pH of the supernatant was measured by the same method as described above, and the pH was 8.6.

  Next, 9 parts by weight of glycerin and 3 parts by weight of water were further added, mixed with a planetary mixer for 30 minutes, and then dispersed with three rolls. Thereafter, 158 parts by weight of water was added and diluted while stirring with a high-speed disper to prepare an inkjet ink (Example 37).

  In order to evaluate the dispersibility of these aqueous electrode inks prepared as described above, the filterability with a 5 μm filter and the state of sedimentation separation of metal particles after 5 hours in a test tube were observed. In addition, the viscosity of these aqueous electrode inks was also evaluated.

  The results are shown in (Table 8).

  In Examples 36 to 37, for comparison, the filterability of the 5 μm filter was better than that of the ink prepared by adding and mixing all the materials at the same time, and the stability of the sedimentation separation was particularly good. .

  As described above, in order to stably disperse particles such as metal powder in the solute in the production process of the aqueous electrode ink in order to stabilize the dispersion, the resin is adsorbed on the surface of the particles, and the resin adsorption layer is used. It is necessary to prevent the cohesion between particles due to steric hindrance. For that purpose, it is better to have a thick water-soluble resin adsorption layer, and in order to slow down the sedimentation speed of metal particles with a large specific gravity, the adsorption layer is made thicker, the apparent specific gravity is reduced, and the sedimentation Stokes diameter is increased Becomes effective. Here, in order to make the adsorption layer thick, it is effective to increase the average molecular weight of the resin adsorbed on the surface of the metal particles. Therefore, when the same kind of resin with different average molecular weight is mixed with metal particles at the same time, the smaller average molecular weight will be adsorbed earlier, so the resin with the surface with the higher average molecular weight is mixed first. The thickness of the adsorption layer can be increased.

  However, dispersibility is stabilized by using only a resin having a large average molecular weight, and the precipitation of metal particles can be suppressed. However, in the case of electrode ink for ink jet printing, if the ink viscosity is not low, it can be ejected from the ink jet head. Can not. In contrast, the aqueous electrode ink can achieve both dispersion stability and reduction in ink viscosity by adding a resin having a low average molecular weight after coating and dispersing on the surface of the metal particles with a resin having a high average molecular weight. A manufacturing method can be realized.

  Further, it should be noted that the ink of Example 37 can be a water-based electrode ink in which separation of Ni powder and barium titanate powder hardly occurs.

  What is important here is that the thickness of the resin layer attached to the surface of the metal particles changes in the pH state of the solution in which the metal particles and the resin having a large average molecular weight are mixed. In general, a resin having a large average molecular weight is considered to aggregate in a string shape in a poor solvent and spread in a good solvent.

  Therefore, it is known that the amount of the resin adsorbed on the surface of the metal particles is increased by the method of adsorbing in the poor solvent.

  In particular, the pH of the solution is set to pH = 5 to 7 on the acidic side at the beginning of the ink manufacturing process in which the adsorption of the resin to the metal particles is completed, and the pH is set to the alkaline side at the end of the ink manufacturing process.

  In view of the above, by setting the pH at the initial stage of the ink production process to 5 to 7, the water-soluble resin is completely adsorbed on the surface of the metal particles in the state of being aggregated in a string shape. In this state, since the water-soluble resin is curled up in a string shape and the exclusive area is smaller than when adsorbed in a good solvent in which the polymer chain spreads, the amount of adsorption of the water-soluble resin on the metal particles is larger. The water containing nickel powder used in the fourth embodiment is a poor solvent because it is an acidic solution.

  Next, when adsorption is completed in a poor solvent, barium titanate is added to bring the pH to the alkali side to make a good solvent solution atmosphere, and the polymer chain becomes a metal due to steric hindrance with the adjacent adsorbed polymer. The molecular chain is radially extended from the surface of the particle, and the adsorption layer of the water-soluble resin becomes thick. This makes it possible to realize a method for producing a water-based electrode ink with less dispersion stability and sedimentation as described above.

  In addition, in order to bring the pH to the acidic side at the beginning of the ink production process, it may be possible to change the order in which materials are added. May be changed.

  Furthermore, since triethanolamine, which is a water-based plasticizer, exhibits alkalinity, the pH of the final ink can be made alkaline by adding this triethanolamine in the final stage of ink preparation.

  In addition, in the case of ink for ink jet printing, since the pH of the final ink is preferably alkaline in order to prevent corrosion of electrodes etc. in contact with the ink inside the ink jet head, the pH of the ink is finally reduced. It is desirable to be alkaline.

  As described above, the water-based electrode ink and the method for producing the same according to the present invention enable a fine electrode pattern to be printed on a printed material constituting an electronic component or the like without contact and on-demand printing under computer control. This is useful for parts.

Claims (11)

A water-based electrode ink for forming an internal electrode pattern by printing on a ceramic green sheet by inkjet and firing together with the ceramic green sheet,
The content of the metal powder with respect to the total weight of the water-based electrode ink is 25 to 40% by weight, and at least two kinds of water-soluble resins having different average molecular weights selected from water-soluble resins are 3 per 100 parts by weight of the metal powder. Containing 6 parts by weight, containing a water-based plasticizer 1.5 to 1.9 times by weight with respect to the water-soluble resin, the remainder comprising water
The water-soluble resin, a water-soluble resin average molecular weight flat is 5000 to 10000, and an average molecular weight attached to the surface of the metal powder contains from 150000 to 360000 of the water-soluble resin, water-based electrode ink.   The water-based electrode ink according to claim 1, wherein the water-soluble resin is a nonionic or cationic resin.   The water-based electrode ink according to claim 1, wherein the water-soluble resin contains at least one of an ammonium salt of isobutylene / maleic anhydride copolymer or polyvinylpyrrolidone.   The aqueous electrode ink according to claim 1, comprising at least triethanolamine as an aqueous plasticizer.   The water-based electrode ink according to claim 1, wherein the metal powder is a noble metal such as gold, silver, platinum, palladium, or an alloy thereof.   The aqueous electrode ink according to claim 1, wherein the metal powder is a base metal of copper, nickel, or an alloy thereof.   The aqueous electrode ink according to claim 1, wherein the average particle diameter of the metal powder is 0.05 to 0.4 μm. A water-based electrode ink for forming an internal electrode pattern by printing on a ceramic green sheet by inkjet and firing together with the ceramic green sheet,
The content of the nickel powder is 25 to 40% by weight with respect to the total weight of the aqueous electrode ink, the barium titanate powder is 10 to 25 parts by weight with respect to 100 parts by weight of the nickel powder, and is selected from water-soluble resins. 3 to 6 parts by weight of water-soluble resin having at least two kinds of different average molecular weights with respect to 100 parts by weight of nickel powder, and 1.5 to 1.9 times by weight ratio of water-based plasticizer to water-soluble resin Contains, the rest consists of water,
The water-soluble resin, a water-soluble resin average molecular weight flat is 5000 to 10000, and an average molecular weight attached to the surface of the metal powder contains from 150000 to 360000 of the water-soluble resin, water-based electrode ink. A water-based electrode ink for forming an internal electrode pattern by printing on a ceramic green sheet by inkjet and firing together with the ceramic green sheet,
The silver powder content is 25 to 40% by weight with respect to the total weight of the aqueous electrode ink, the glass powder is 0.5 to 10 parts by weight with respect to 100 parts by weight of the silver powder, or the manganese oxide powder is silver 100. It contains 0.5 to 5 parts by weight with respect to parts by weight, and contains 3 to 6 parts by weight of water-soluble resins having at least two kinds of average molecular weights selected from water-soluble resins with respect to 100 parts by weight of metal powder. , Containing a water-based plasticizer in a weight ratio of 1.5 to 1.9 times with respect to the water-soluble resin, the rest is made of water,
The water-soluble resin, a water-soluble resin average molecular weight flat is 5000 to 10000, and an average molecular weight attached to the surface of the metal powder contains from 150000 to 360000 of the water-soluble resin, water-based electrode ink.   The aqueous electrode ink according to claim 1 includes a step of mixing and dispersing a metal powder, a water-soluble resin having a large average molecular weight, and water, and adding a water-soluble resin having a small average molecular weight and a water-based plasticizer after the mixing and dispersing. A method for producing an aqueous electrode ink produced by a step of further mixing and dispersing.   The water-based electrode ink according to claim 8 includes a step of mixing and dispersing nickel powder, a water-soluble resin having a large average molecular weight, and water, a water-soluble resin having a small average molecular weight after mixing and dispersing, a water-based plasticizer, and titanium. A method for producing a water-based electrode ink produced by a step of adding barium acid powder and further mixing and dispersing.