KR102056972B1 - Conductive ink - Google Patents

Abstract

The conductive ink for transfer printing which can bake the electrically conductive film pattern which has sufficient electroconductivity and favorable adhesiveness with a board | substrate at low temperature is provided. The conductive ink for transfer printing containing metal particle | grains, the solvent containing ethanol, and 0.1-3.0 mass% of high boiling point solvents which have a hydroxyl group.

Description

Conductive Ink {CONDUCTIVE INK}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive ink used for forming wirings and electrode patterns of semiconductor integrated circuits, and the like, and capable of forming wirings and electrode patterns for organic thin film transistor substrates. In more detail, this invention relates to the conductive ink which can be used suitably for formation of the wiring and electrode pattern using the transfer printing method including the reverse printing method.

Conventionally, after forming a metal thin film in the whole surface of a board | substrate by sputter | spatter, vapor deposition, etc., the method of etching the unnecessary part by the photolithographic method and forming a required conductive film pattern is known. However, the method requires the use of expensive vacuum apparatus in addition to the complicated process.

For this reason, the method of forming a simpler and more inexpensive conductive film pattern is calculated | required, and the method using the printing methods, such as the convex printing method, the recessed printing method, the screen printing method, the inkjet printing method, is proposed in recent years. Moreover, as a printing method which can form a higher precision pattern, the method using the reverse printing method, the micro contact printing method, etc. is proposed, and various inks, such as electroconductive ink, insulating ink, and resistance ink suitable for these printing methods, are proposed. Is developed.

In patent document 1, the electroconductive ink for forming the fine conductive film pattern by a convex plate inversion printing method is proposed, and specifically, it contains a binder component for forming a conductive film pattern by the convex plate inversion printing method substantially. A conductive ink that does not contain a conductive particle having a volume average particle diameter (Mv) of 10 to 700 nm, a releasing agent, a surface energy regulator, and a solvent component as essential components, and the solvent component has a surface energy of 25 mN / m or more at 25 ° C. And a boiling point under atmospheric pressure is a mixture with a volatile solvent of 120 ° C. or lower, and an ink surface energy at 25 ° C. is 10 to 21 mN / m, and a conductive ink is disclosed.

By using the electroconductive ink of the said patent document 1, a fine conductive film pattern can be stably formed by a convex plate reversal printing method without a transfer defect, for example, when silver is used as electroconductive particle, the fine pattern formed By firing at a low temperature of 200 ° C. or lower, it is possible to impart excellent conductivity with a resistivity of 10 ⁻⁵ Pa · cm order or less, and in addition to excellent transferability, it is possible to form a fine pattern in all transfers. Doing.

Moreover, in patent document 2, it is "16 mN / m or more and 23 mN / m or less when the dynamic surface tension in 25 degreeC calculated | required according to the maximum bubble pressure method is measured by setting the bubble generation period to 0.05 Hz, and The ink which made 20 mN / m or more and 27 mN / m or less when measured by setting the said generation period to 10.0 Hz "is disclosed.

The ink is inverted to have an appropriate wettability and mold release property with respect to the surface of the silicon blanket, and to provide an ink pattern having a uniform thickness without stains or defects on the surface of a printed object such as a substrate by adjusting the dynamic surface tension to an appropriate range. Printing ink.

: International Publication No. WO2008 / 111484 Japanese Unexamined Patent Publication No. 2011-252072

However, although the fine pattern can be formed by using the electroconductive ink of the said patent document 1, since it does not contain a binder substantially, the adhesiveness of the electrically conductive film pattern formed on the board | substrate exists. Moreover, in order to express electroconductivity, the baking temperature is 180 degreeC or more, and there exists a problem that the inexpensive base material inferior in heat resistance cannot be used.

Moreover, the ink disclosed by the said patent document 2 is an ink suitable mainly for the color filter which comprises a liquid crystal display, cannot be used as a conductive ink suitable for transfer printing methods, such as a reverse printing method as it is, and the solvent which melt | dissolves a binder comparatively Since it contains a large amount, it needs to dry for a comparatively long time after coating on the silicon blanket surface, and there existed a problem in that the printing tact was comparatively long.

Therefore, the objective of this invention was made | formed in view of the subject which the said prior art has, and is an electroconductive ink for transfer printing which can be used suitably for the transfer printing method containing a reverse printing method etc., and it has sufficient electroconductivity and favorable adhesiveness with a board | substrate. It is providing the conductive ink for transfer printing which can bake the conductive film pattern which has a low temperature.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching so that the said objective may be achieved, this inventor is a conductive ink for transfer printing which can be used suitably for the transfer printing method including a reverse printing method etc., and has sufficient electroconductivity and favorable adhesiveness with a board | substrate. In order to obtain the conductive ink for transfer printing capable of baking the conductive film pattern at a low temperature, it has been found that it is extremely effective to include a high boiling point solvent having an appropriate amount of metal particles and a specific hydroxyl group to achieve the above object. Invented.

That is, the present invention,

A metal particle, a solvent containing ethanol,

Conductive ink for transfer printing comprising 0.1 to 3.0% by mass of a high boiling point solvent having a hydroxyl group

to provide.

Among the "transfer printing methods" in the present invention, the representative "inverting printing method" will be described. In the "inverting printing method", ink is applied on a blanket such as a silicone resin to form an ink coating surface, and the ink on the contact surface of the convex plate is removed from the blanket by pressing a convex plate for removing a non-image portion on the ink coated surface. Then, it is a printing method for transferring the ink remaining on the blanket to the printed object.

In the conductive ink for transfer printing of the present invention, more preferably, the high boiling point solvent contains 1,3-butylene glycol, 2,4-diethyl-1,5-pentanediol or octanediol.

Moreover, it is preferable that the electroconductive ink for transcription | transfer printing of this invention contains hydrofluoro ether further.

In addition, the conductive ink for transfer printing of the present invention,

The metal particles are silver fine particles,

With silver particles,

Short-chain amines having 5 or less carbon atoms and a partition coefficient (logP) of -1.0 to 1.4,

High polar solvent,

Dispersant having an acid value for dispersing the silver fine particles

It is preferable to contain the containing silver fine particle dispersion.

In addition, the conductive ink for transfer printing of the present invention,

In the said silver fine particle dispersion, it is preferable that the said short chain amine is an alkoxyamine and contains the protective dispersing agent which has an acid value further.

In addition, in the conductive ink for transfer printing of the present invention,

It is preferable that the acid value of the said protective dispersing agent is 5-200, and has a functional group derived from phosphoric acid.

According to the conductive ink for transfer printing of the present invention, a conductive ink for transfer printing that can be suitably used for a transfer printing method including a reverse printing method, can be baked at a low temperature a conductive film pattern having sufficient conductivity and good adhesion to a substrate. Conductive ink for transfer printing can be realized.

Hereinafter, (1) one preferred embodiment of the conductive ink for transfer printing of the present invention, (2) one suitable embodiment of the method for producing a conductive ink for transfer printing of the present invention, and (3) the conductive ink for transfer printing of the present invention The conductive film pattern used and its manufacturing method are explained in full detail. In the following description, redundant descriptions may be omitted.

(1) conductive ink for transfer printing

The electroconductive ink for transfer printing of this embodiment is characterized by containing 0.1-3.0 mass% of metal particle | grains, the solvent containing ethanol, and the high boiling point solvent which has a hydroxyl group. Moreover, it contains the solid content which has a metal particle dispersion (in other words, metal colloid) particle | grains which consist of metal particle and an organic component as a main component, and the dispersion medium which disperse | distributes these solid content. In addition, in the said colloidal liquid, a "dispersion medium" may melt | dissolve a part of said solid content.

According to such a metal colloidal liquid, since it contains an organic component, the dispersibility of the metal colloidal particle in a metal colloidal liquid can be improved, Therefore, a metal colloidal particle will aggregate even if the content of the metal component in a metal colloidal liquid is increased. It is difficult and can maintain good dispersion stability. On the other hand, "dispersibility" as used here shows whether the dispersion state of the metal particle in the said metal colloid liquid is an excellent state immediately after preparing a metal colloid liquid, or "dispersion stability", After adjusting a metal colloid liquid and passing a predetermined time, it shows whether the dispersion state of the metal particle in the said metal colloid liquid is maintained, and it can also be called "low sedimentation cohesion".

Here, in said metal colloidal liquid, the "organic component" in a metal colloidal particle is an organic substance which comprises metal colloid particle substantially with the said metal component. In the organic component, such as a trace organic substance initially contained as an impurity in a metal, an organic substance in which a trace organic substance mixed in a manufacturing process described later is attached to a metallic component, a residual reducing agent which cannot be removed in a washing process, a residual dispersant, and the like, Organic matters attached to the metal component in trace amounts are not included. In addition, with said "trace amount", less than 1 mass% is specifically intended in a metal colloid particle.

Since the metal colloidal particle in this embodiment contains the organic component, dispersion stability in a metal colloidal liquid is high. Therefore, even if the content of the metal component in the metal colloidal liquid is increased, the metal colloidal particles hardly aggregate, and as a result, good dispersibility is maintained.

In addition, the "solid content" of the metal colloid liquid in this embodiment is a silica gel etc., after removing a dispersion medium from a metal colloid liquid, for example, it is 24 at normal temperature (for example, 25 degreeC) of 30 degrees C or less. The thing of solid content remaining at the time of drying is said, and usually contains a metal particle, a residual organic component, a residual reducing agent, etc. On the other hand, as a method of removing the dispersion medium from the metal colloidal liquid using silica gel, various methods can be employed. For example, the metal colloidal liquid is applied onto a glass substrate, and the coating film is placed in a sealed container containing silica gel. The dispersion medium may be removed by leaving the attached glass substrate for 24 hours or longer.

In the metal colloidal liquid of this embodiment, preferable solid content concentration is 1-60 mass%. When the concentration of the solid content is 1% by mass or more, the content of the metal in the conductive ink for transfer printing can be ensured, and the conductivity efficiency is not low. Moreover, when the concentration of solid content is 60 mass% or less, the viscosity of a metal colloidal liquid does not increase, handling is easy, industrially advantageous, and can form a flat thin film. More preferable solid content concentration is 5-40 mass%.

The electroconductive ink for transfer printings of this invention contains 0.1-3.0 mass% of high boiling point solvents which have a hydroxyl group. It is characterized by the above-mentioned. The high boiling point solvent which has a hydroxyl group is 200 degreeC by 1, 3- butylene glycol (boiling point: 203 degreeC), 2, 4-diethyl- 1, 5- pentanediol (boiling point: 150 degreeC / 5mmHg, 1 atmosphere) Or more) or an octanediol (boiling point: 243 degreeC) is preferable.

The "high boiling point solvent" used in this invention means the solvent which has a boiling point of 200 degreeC or more. Moreover, since it has a moderate affinity with water and tends to moisturize by absorbing or adsorption | suctioning water | moisture content in air by having a hydroxyl group, it can be set as the ink suitable for the transfer printing method with a small addition amount. Moreover, by making the addition amount of a high boiling point solvent minimum required, the ink apply | coated on the silicone blanket can be semi-dried for a short time, and the effect that a printing tact can be shortened is exhibited.

The addition amount of the high boiling point solvent which has a hydroxyl group is 0.1-3.0 mass%. If it is less than 0.1 mass%, the amount is too small to be in an ink state suitable for the transfer printing method. If it exceeds 3.0 mass%, the time for reaching a semi-dry state suitable for the transfer printing method becomes long, which is disadvantageous in terms of printing tact. . The addition amount of the high boiling point solvent which has a hydroxyl group is 0.3-2.0 mass% more reliably, and it becomes easy to become the ink state suitable for the transfer printing method, and can shorten the time to reach the semi-dry state suitable for the transfer printing method, Particular preference is given from the viewpoint of being advantageous in terms of printing tact.

In addition, in the conductive ink for transfer printing of the present invention, a high volatile solvent such as ethanol is added to increase the dryness of the ink. By adding the solvent, the conductive ink for transfer printing can be quickly adjusted to a viscosity suitable for printing. As the high volatile solvent, one or two or more low-boiling solvents selected from the group of solvents having a boiling point of less than 100 ° C such as methanol, propyl alcohol, isopropyl alcohol, acetone, n-butanol, sec-butanol, tert-butanol, etc. It is available.

Moreover, in the conductive ink for transfer printing of this invention, it is preferable to contain fluorine solvents, such as hydrofluoroether. Since the fluorine solvent has a low surface tension, good wettability can be exhibited with respect to the silicone blanket, and since the boiling point is relatively low, good fluorescence can be imparted. Especially, hydrofluoroether is more preferable than the fluorine solvent containing a halogen atom from a viewpoint of an ozone destruction coefficient.

In addition, hydrofluoroethers have an advantage of having higher polarity and less swelling of a silicone blanket because they have ether bonds than hydrofluorocarbons, and have good compatibility with alcohols such as ethanol and are dispersed in alcohol Since the effect which is excellent also in compatibility with a metal particle is exhibited, it is more preferable.

In the conductive ink for transfer printing of the present invention, a fluorine-based surfactant having a fluorine atom may be added for the purpose of improving the wettability with respect to the silicon blanket. However, in this case, when the addition amount is too large, the conductivity of the conductive film produced using the conductive ink for transfer printing is lowered. When the addition amount is too small, the effect of improving wettability is insufficient, so that it is preferably 0.01 to 2% by mass.

In the conductive ink for transfer printing of the present invention, the surface tension is 22 mN / m or less. By sufficiently lowering the surface tension to 22 mN / m or less, the wettability of the conductive ink for transfer printing onto a blanket such as a silicone resin can be sufficiently secured. The surface tension of 22 mN / m or less can be realized by adjusting the component ratio of the conductive ink for transfer printing of the present invention described above. The lower limit of the surface tension may be about 13 mN / m. On the other hand, the surface tension referred to in the present invention is obtained by measuring on the principle called the plate method (Wilhelmy method), for example, a fully automatic surface tension meter CBVP manufactured by Kyowa Kaimen Kagaku Co., Ltd. It can measure by -Z etc.

Here, the conductive ink for transfer printing of the present embodiment has silver fine particles and short chain amines having 5 or less carbon atoms and a distribution coefficient (logP) of -1.0 to 1.4, a high polar solvent, and an acid value for dispersing the silver fine particles. It is preferable that it is comprised from the silver fine particle dispersion (for example, colloidal shape) containing a dispersing agent. Below, the detail of this silver fine particle dispersion, each component, etc. is demonstrated.

The silver fine particle dispersion of this embodiment contains silver fine particles, the short-chain amine which has 5 or less carbon atoms, and a high polar solvent, for example, has the form of the colloidal colloid liquid. As for the form of the silver fine particles (silver colloidal particles) contained in the solid content of the silver fine particle dispersion, for example, silver colloidal particles in which an organic component is attached to the surface of particles composed of silver components, and the silver component Although silver colloidal particle | grains comprised by the particle | grains which make up the core and the surface is coat | covered with the organic component, and silver colloidal particle | grains comprised by the silver component and organic component being mixed uniformly are mentioned, It does not specifically limit. As a core, the particle | grains which consist of a silver component are the silver colloidal particle | grains comprised by the surface being coat | covered with the organic component, or the silver colloidal particle | grains comprised by the silver component and organic component being mixed uniformly. On the other hand, those skilled in the art can appropriately prepare the silver colloidal particles having the above-described form using known techniques in the field.

(1-1) silver fine particles

The average particle diameter of the silver fine particles contained in the silver fine particle dispersion in the present embodiment is not particularly limited as long as it is a range that does not impair the effects of the present invention. However, it is preferable to have an average particle diameter such that melting point drops occur. 1 to 400 nm may be sufficient. Moreover, it is preferable that it is 1-70 nm. When the average particle diameter of the silver fine particles is 1 nm or more, the silver fine particles have good low-temperature sintering properties, and the production of silver fine particles does not become expensive and is practical. Moreover, if it is 400 nm or less, the dispersibility of silver fine particles hardly changes with time, and it is preferable. In addition, also in the electroconductive ink for transfer printing obtained using the silver fine particle dispersion of this embodiment, the average particle diameter (median diameter) of silver colloid particle | grains (containing silver fine particles) is substantially the same as this range (it can be approximated). ).

On the other hand, the particle diameter of silver fine particles in a silver fine particle dispersion fluctuates by solid content concentration, and is not necessarily constant, and does not need to be constant. Moreover, when a silver fine particle dispersion contains the dispersing agent etc. which are mentioned later as an arbitrary component, although the average particle diameter may contain the silver fine particle component of more than 400 nm, the effect of this invention is remarkably made without causing aggregation. As long as it is a component which does not harm, it may contain the silver fine particle component which has an average particle diameter of more than 400 nm.

Here, the average particle diameter of silver microparticles | fine-particles in the silver fine particle dispersion of this embodiment is based on the dynamic light scattering method (Doppler scattering light analysis), For example, the dynamic light scattering made by Horiba Seishakukusho Co., Ltd. It can be expressed by the median diameter (D50) based on the volume measured by the particle size distribution measuring device LB-550. Specifically, several droplets of the metal colloidal liquid are dropped in 10 mL of ethanol, and it vibrates and disperse | distributes by hand and a sample for a measurement is prepared. Next, 3 mL of the sample for a measurement is thrown into the cell of the dynamic light scattering particle size distribution measuring apparatus LB-550 made by Horiba Seishaku Co., Ltd., and it measures on condition of the following.

·Measuring conditions

The number of data reading: 100 times

Cell holder temperature: 25 degrees Celsius

Display condition

Distribution Type ： Standard

Repetition number of times: 50 times

Based on particle diameter: based on volume

Refractive index of dispersoid: 0.200-3.900i (in the case of silver)

Refractive index of the dispersion medium: 1.36 (in the case of ethanol as a main component)

System condition setting

Strength standard: Dynamic

Scattering intensity range upper limit: 10000.00

Scattering intensity range lower limit: 1.00

(1-2) Short-chain amines having 5 or less carbon atoms

In the silver fine particle dispersion of this embodiment, at least one part of the surface of silver fine particles has a C5 or less short-chain amine. On the other hand, a small amount of organic matter adheres to the surface of the silver fine particles, such as trace organic substances initially contained as impurities in the raw materials, trace organic substances mixed in the manufacturing process described later, residual reducing agents and residual dispersants which cannot be removed in the washing process. You may be.

The short-chain amine having 5 or less carbon atoms is not particularly limited as long as the partition coefficient (logP) is -1.0 to 1.4, and may be linear or branched, and may have side chains. Examples of the short-chain amines include ethylamine (-0.3) propylamine (0.5), butylamine (1.0), N- (3-methoxypropyl) propane-1,3-diamine (-0.6), 1, 2-ethanediamine, N- (3-methoxypropyl)-(-0.9), 2-methoxyethylamine (-0.9), 3-methoxypropylamine (-0.5), 3-ethoxypropylamine (- 0.1), 1,4-butanediamine (-0.9), 1,5-pentanediamine (-0.6) pentanolamine (-0.3), aminoisobutanol (-0.8), and the like. It is preferable to use.

The said short chain amine may be a compound containing functional groups other than an amine, such as a hydroxyl group, a carboxyl group, an alkoxy group, a carbonyl group, ester group, and a mercapto group, for example. In addition, the said amines may be used independently, respectively and may use 2 or more types together. In addition, it is more preferable that boiling points at normal temperature are 300 degrees C or less and 250 degrees C or less.

As long as the silver particle dispersion of this embodiment is a range which does not impair the effect of this invention, in addition to said short-chain amine which has 5 or less of said carbon numbers, it may contain the carboxylic acid. Although the carboxyl group in one molecule of the carboxylic acid has a relatively high polarity and is likely to cause interaction by hydrogen bonding, portions other than these functional groups have a relatively low polarity. Moreover, a carboxyl group tends to exhibit acidic property. When the carboxylic acid is localized (attached) to at least a part of the surface of the silver fine particles (that is, at least part of the surface of the silver fine particles) in the silver particle dispersion of the present embodiment, the solvent and the silver fine particles are formed. It can be made affinity sufficiently and can prevent aggregation of silver fine particles (dispersion property is improved).

As carboxylic acid, the compound which has at least 1 carboxyl group can be used widely, For example, formic acid, oxalic acid, acetic acid, hexanoic acid, acrylic acid, octylic acid, oleic acid, etc. are mentioned. Some carboxyl groups of the carboxylic acid may form a salt with a metal ion. In addition, about the said metal ion, 2 or more types of metal ion may be contained.

The said carboxylic acid may be a compound containing functional groups other than carboxyl groups, such as an amino group, a hydroxyl group, an alkoxy group, a carbonyl group, ester group, and a mercapto group, for example. In this case, it is preferable that the number of carboxyl groups is more than the number of functional groups other than a carboxyl group. In addition, the said carboxylic acid may be used independently, respectively and may use 2 or more types together. In addition, it is more preferable that boiling points at normal temperature are 300 degrees C or less and 250 degrees C or less. In addition, amines and carboxylic acids form amides. Since the said amide group is adsorb | sucked to the surface of silver fine particles suitably, the amide group may adhere to the surface of silver fine particles.

When a colloid is comprised by the silver fine particles and the organic substance (the short-chain amine which has 5 or less carbon atoms) adhered to the surface of the said silver fine particles, it is preferable that content of the organic component in the said colloid is 0.5-50 mass%. If the content of the organic component is 0.5% by mass or more, the storage stability of the silver fine particle dispersion obtained tends to be good, and if it is 50% by mass or less, the conductivity of the fired body obtained by heating the silver fine particle dispersion tends to be good. More preferable content of an organic component is 1-30 mass%, and further more preferable content is 2-15 mass%.

(1-3) High Polar Solvent

In the silver fine particle dispersion of the present embodiment, silver fine particles are dispersed in various high polar solvents.

As said solvent, various high polar solvents can be used in the range which does not impair the effect of this invention. As a high polar solvent, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, 2-butanol, pentanol, hexanol, isoamyl alcohol, perryl alcohol, nitromethane, acetonitrile, pyridine, acetonecresol, dimethylformamide , Dioxane, ethylene glycol, glycerin, phenol, p-cresol, propyl acetate, isopropyl acetate, tert-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 3-methyl-1 -Pentanol, 3-methyl-2-pentanol, 2-butanol, 1-hexanol, 2-hexanol 2-pentanone, 2-heptanone, acetic acid 2- (2-ethoxyethoxy) ethyl, acetic acid Although 2-butoxyethyl, 2- (2-butoxyethoxy) ethyl acetate, 2-methoxyethyl acetate, 2-hexyloxyethanol, etc. can be illustrated, In the present invention, the above-mentioned short-chain amine having 5 or less carbon atoms and Since compatibility is favorable, it is preferable to use C1-C6 alcohol. In addition, these solvent may be used independently, respectively and may use 2 or more types together.

(1-4) dispersant

The silver particle dispersion of this embodiment further contains the "dispersing agent which has an acid value" added after silver particle synthesis in order to disperse silver fine particles. By using such a dispersing agent, the dispersion stability of silver fine particles in a solvent can be improved. Here, it is more preferable that the acid value of the said dispersing agent is 5-200, and it is further more preferable that the said dispersing agent has a functional group derived from phosphoric acid.

If the acid value of the dispersing agent is 5 or more, the adsorption will start to occur in the acidic interaction with the amine and the metal surface whose particle surface becomes alkaline. If it is 200 or less, it will not have an excessive adsorption site. Because it becomes. In addition, since the dispersant has a functional group derived from phosphoric acid, phosphorus (P) interacts with the metal (M) through oxygen (O) and is attracted to each other, which is most effective for adsorption with a metal or a metal compound. This is because suitable dispersibility can be obtained.

On the other hand, examples of the polymer dispersant having an acid value of 5 to 200 include SOLSPERSE-16000, 21000, 41000, 41090, 43000, 44000, 46000, 54000, and the like in the SOLSPERSE series of Lubrizol Corporation. DISPERBYK-102, 110, 111, 170, 190.194N, 2015.2090, 2096 and the like, and Evonik's TEGO Dispers series includes 610, 610 S, 630, 651, 655, 750W, 755W, The Disparon series manufactured by Kusumoto Kasei Co., Ltd. includes DA-375, DA-1200, and the like. The WK series is manufactured by Kyoeikagaku Kogyo Co., Ltd. -13E, G-700, G-900, GW-1500, GW-1640, WK-13E can be illustrated.

Although content in the case of containing a dispersing agent in the silver fine particle dispersion of this embodiment may be adjusted by desired characteristics, such as a viscosity, For example, when using a silver fine particle dispersion as a silver ink, content of a dispersing agent is 0.5. It is preferable to set it as -20 mass%, and when using as a silver paste, it is preferable to make content of a dispersing agent into 0.1-10 mass%.

It is preferable that content of a polymer dispersing agent is 0.1-15 mass%. When content of a polymeric dispersing agent is 0.1% or more, the dispersion stability of the silver fine particle dispersion obtained will improve, but when there is too much content, low temperature sintering property will fall. From such a viewpoint, more preferable content of a polymer dispersing agent is 0.3-10 mass%, and further preferable content is 0.5-8 mass%.

It is preferable that the silver fine particle dispersion of this embodiment is 10 mass% or less in weight loss at 100-500 degreeC when thermogravimetric analysis is performed at the temperature increase rate of 10 degree-C / min with respect to solid content. When the solid is heated to 500 ° C., organic matters and the like are oxidatively decomposed, and most of them are gasified and disappeared. For this reason, the weight loss by heating to 500 degreeC can correspond to the quantity of the organic substance in solid content substantially.

The more the weight loss is, the more excellent the dispersion stability of the silver fine particle dispersion is, but if too large, the organic matter remains in the conductive ink for transfer printing as an impurity, thereby lowering the conductivity. In particular, in order to obtain a highly conductive conductive film pattern by heating at a low temperature of about 100 ° C, the weight loss is preferably 20% by mass or less. On the other hand, if the weight loss is too small, the dispersion stability in the colloidal state is impaired, so it is preferably 0.1% by mass or more. More preferable weight loss is 0.5-15 mass%.

(1-5) Protective Agent (Protective Dispersant)

The silver fine particle dispersion of this embodiment may contain the dispersing agent (protective dispersing agent) which further has an acid value as a protective agent added before silver fine particle synthesis. The "protective dispersant" here may be the same kind as the "dispersing agent which has an acid value" added after the said silver fine particle synthesis | combination, or a different kind may be sufficient as it.

(1-5) Other Ingredients

In addition to the above components, the silver fine particle dispersion of the present embodiment, in order not to impair the effects of the present invention, in order to impart a suitable viscosity, adhesiveness, dryness or printability according to the purpose of use, For example, you may add arbitrary components, such as an oligomer component, a resin component, an organic solvent (it may melt | dissolve or disperse | distribute a part of solid content), surfactant, a thickener, or a surface tension modifier which plays a role as a binder. Such optional components are not particularly limited.

As the resin component, for example, polyester resins, polyurethane resins such as blocked isocyanate, polyacrylate resins, polyacrylamide resins, polyether resins, melamine resins or terpene resins, etc. These may be used individually, respectively and may use 2 or more types together.

As the thickener, for example, clay minerals such as clay, bentonite or hectorite, for example, emulsions such as polyester emulsion resins, acrylic emulsion resins, polyurethane emulsion resins or block isocyanates, methylcellulose, carboxymethyl cellulose And polysaccharides such as cellulose derivative of hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, xanthan gum or guar gum, and the like, and these may be used alone or in combination of two or more thereof.

You may add surfactant different from the said organic component. In the inorganic colloidal dispersion liquid of a multicomponent solvent system, roughness of the surface of a film by the difference of the volatilization rate at the time of drying, and the deviation of solid content are easy to produce. By adding surfactant to the silver fine particle dispersion of this embodiment, the silver fine particle dispersion which can suppress these disadvantages and can form a uniform electroconductive film can be obtained.

The surfactant that can be used in the present embodiment is not particularly limited, and any one of anionic surfactant, cationic surfactant, and nonionic surfactant can be used, for example, alkylbenzene sulfonate, quaternary Ammonium salt etc. are mentioned. Especially, since an effect can be acquired with a small amount of addition amount, a fluorine type surfactant and a silicone type surfactant are preferable. If the content of the surfactant is too small, the effect cannot be obtained. If the content of the surfactant is too large, the remaining impurities in the film may be impaired. Content of preferable surfactant is 0.01-5 mass parts with respect to 100 mass parts of dispersion medium of silver fine particle dispersion.

Silver microparticles | fine-particles in this embodiment are silver microparticles | fine-particles with the alkoxyamine whose distribution coefficient logP is -1.0-1.4 and carbon number 5 or less to at least one part of a surface. By attaching an alkoxyamine having 5 or less carbon atoms having a distribution coefficient (logP) of -1.0 to 1.4 to at least a part of the surface of the silver fine particles, excellent dispersibility and low temperature sinterability to various solvents (especially high polar solvents) to the silver fine particles Can be given.

As said solvent, various solvent can be used in the range which does not impair the effect of this invention, The solvent whose SP value (dissolution parameter) is 7.0-15.0 can be used. Here, one of the features of the silver fine particle dispersion of the present invention is that the fine silver particles are uniformly dispersed in the high polar solvent. In the present invention, since the compatibility with the short-chain amine having 5 or less carbon atoms is good, the number of carbon atoms is 1 It is preferable to use the alcohol of -6. In addition, these solvent may be used independently, respectively and may use 2 or more types together.

As a solvent whose SP value (dissolution parameter) is 7.0-15.0, for example, hexane (7.2), triethylamine (7.3), ethyl ether (7.7), n-octane (7.8), cyclohexane (8.3), n Amyl acetate (8.3), isobutyl acetate (8.3), methyl isopropyl ketone (8.4), amylbenzene (8.5) butyl acetate (8.5), carbon tetrachloride (8.6), ethylbenzene (8.7), p-xylene (8.8) , Toluene (8.9), methylpropyl ketone (8.9) ethyl acetate (8.9), tetrahydrofuran (9.2), methyl ethyl ketone (9.3), chloroform (9.4), acetone (9.8), dioxane (10.1), pyridine ( 10.8), isobutanol (11.0), n-butanol (11.1), nitro ethane (11.1) isopropyl alcohol (11.2), m-cresol (11.4), acetonitrile (11.9), n-propanol (12.1), perpril Alcohol (12.5), nitromethane (12.7), ethanol (12.8), cresol (13.3), ethylene glycol (14.2), methanol (14.8) phenol, p-cresol, propyl acetate, isopropyl acetate, tert-butanol, 1- Pentanol, 2-pentanol, 4-methyl-2-pentanol, 3-methyl-1-pentanol, 3-methyl- 2-pentanol, 2-butanol, 1-hexanol, 2-hexanol 2-pentanone, 2-heptanone, 2- (2-ethoxyethoxy) ethyl acetate, 2-butoxyethyl acetate, acetic acid 2 -(2-butoxyethoxy) ethyl, 2-methoxyethyl acetate, 2-hexyloxy ethanol, etc. can be illustrated.

It is preferable that it is the viscosity range of 1-100 cps, and, as for the viscosity of the silver fine particle dispersion of this embodiment, the viscosity range of 1-20 cps is more preferable. By setting it as the said viscosity range, silver fine particle dispersion can be apply | coated uniformly and thinly on a silicone resin. As a coating method, a general coating method can be used, and an applicator method, a bar coater method, a capillary coater method, a spin coating method, etc. can be illustrated.

Adjustment of the viscosity of the silver fine particle dispersion of this embodiment can be performed by adjustment of solid content concentration, adjustment of the compounding ratio of each component, addition of a thickener, etc. In addition, a viscosity can be measured with a vibrating viscometer (for example, VM-100A-L by CBC Corporation). The measurement may be performed by immersing the liquid in the vibrator, and the measurement temperature may be made a normal temperature (20-25 ° C.).

(2) Manufacturing method of conductive ink for transfer printing

In order to manufacture the conductive ink for transfer printing of the present embodiment, first, a silver fine particle dispersion (metal colloidal liquid) is prepared. Next, the conductive ink of this embodiment can be obtained by mixing this metal colloid liquid and the said various components.

Especially, the silver fine particle dispersion of this embodiment has the process of producing silver fine particles, and the process of adding and mixing the dispersing agent which has an acid value for disperse | distributing said silver fine particles to the said silver fine particles. Further, a first pre-process for adjusting a mixed liquid of a silver compound capable of producing metal silver by decomposition by reduction, and a short chain amine having a partition coefficient (logP) of -1.0 to 1.4, and the above-mentioned in the mixed liquid It is preferable to include the 2nd preprocess which produces | generates silver fine particles with a C5 or less short-chain amine attached to at least one part of the surface by reducing a silver compound.

In the said 1st all process, it is preferable to add 2 mol or more of short chain amines with respect to 1 mol of metal silver. By adding the amount of the short chain amine to 2 mol or more with respect to 1 mol of the metal silver, an appropriate amount of the short chain amine can be adhered to the surface of the silver fine particles produced by reduction, and the silver fine particles can be applied to various solvents (especially high polar solvents). Excellent dispersibility and low temperature sintering can be imparted.

On the other hand, the nanoparticles having a melting point drop in the particle diameter of the silver fine particles obtained by the composition of the mixed liquid in the first pre-process and the reducing conditions (for example, heating temperature and heating time) in the second pre-process. It is preferable to set it as a meter size, and it is more preferable to set it as 1-200 nm. Here, the particle | grains of a micron meter size may be contained as needed.

Although the method of taking out silver fine particles from the silver fine particle dispersion obtained by the said 2nd all process is not specifically limited, For example, the method of wash | cleaning the silver fine particle dispersion, etc. are mentioned.

As a starting material for obtaining silver fine particles coated with an organic substance (short chain amine having a distribution coefficient (logP) of -1.0 to 1.4), various known silver compounds (metal salts or hydrates thereof) can be used. For example, silver nitrate And silver salts such as silver chloride, silver chloride, silver oxide, silver acetate, silver oxalic acid, silver formic acid, silver acetate, chloric acid silver, and emulsified silver. These are not particularly limited as long as they can be reduced, and may be dissolved in a suitable solvent or used while being dispersed in a solvent. Moreover, these may be used independently or may use multiple use together.

Moreover, the method of reducing these silver compounds in the said raw material liquid is not specifically limited, For example, the method of using a reducing agent, the method of irradiating light, such as an ultraviolet-ray, an electron beam, an ultrasonic wave, or a thermal energy, the method of heating, etc. Can be mentioned. Especially, the method of using a reducing agent is preferable from a viewpoint of easy operation.

Examples of the reducing agent include amine compounds such as dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone and hydrazine; for example, hydrogen compounds such as sodium borohydride, hydrogen iodide and hydrogen gas; For example, oxides such as carbon monoxide and sulfurous acid; for example, ferrous sulfate, iron oxide, iron fumarate, iron lactate, iron oxalate, iron emulsion, tin acetate, tin chloride, tin phosphate, tin oxalate, and tin oxide Low-valent metal salts such as tin sulfate and tin sulfate; sugars such as ethylene glycol, glycerin, formaldehyde, hydroquinone, pyrogarol, tannin, tannic acid, salicylic acid, D-glucose, and the like. It will not specifically limit, if it can reduce the said metal salt. When using the said reducing agent, you may accelerate | stimulate a reduction reaction by adding light and / or heat.

As a specific method for preparing silver fine particles coated with an organic substance using the metal salt, organic component, solvent and reducing agent, for example, the metal salt is dissolved in an organic solvent (for example, toluene) to prepare a metal salt solution, A short chain amine as a protective dispersing agent and a protective dispersing agent which has an acid value are added to the said metal salt solution, Then, the method of gradually dropping the solution in which the reducing agent was melt | dissolved here, etc. are mentioned.

In addition to silver microparticles, the dispersion liquid containing silver microparticles | fine-particles coat | covered with the protective dispersing agent which has a short chain amine obtained by the above, and an acid value, the residue of a metal salt, a reducing agent, and a dispersing agent exist, There exists a tendency for electrolyte concentration and organic substance concentration to be high. The liquid in such a state coagulates with the metal particles due to high conductivity and is likely to precipitate. Or even if it is not precipitated, if the dispersant which is more than the amount required for counter ion of a metal salt, the residue of a reducing agent, or dispersion | distribution remains, there exists a possibility that electroconductivity may deteriorate. Thus, by washing the solution containing the silver fine particles and removing excess residue, the silver fine particles coated with the organic substance can be reliably obtained.

As the washing method, for example, a solvent (for example, water, methanol, methanol, which precipitates the silver fine particles after the dispersion liquid containing the silver fine particles coated with the organic component is allowed to stand for a certain time, and the resulting fine liquid is removed) / Water mixed solvent, etc.), and the method of stirring again and removing the supernatant liquid generated by standing for a certain time is repeated several times, the method of centrifugation instead of the above, the ultrafiltration device or the ion exchange device. The desalination method etc. are mentioned. By removing excess residue and removing an organic solvent by such washing | cleaning, the metal particle coat | covered with the "dispersing agent which has a short chain amine and an acid value" of this embodiment can be obtained.

In this embodiment, silver fine particle dispersion (silver colloidal dispersion) is obtained by mixing the silver fine particle coat | covered with the protective dispersing agent which has the short chain amine obtained above and an acid value, and the dispersion medium demonstrated by the said this embodiment. The method for mixing the metal particles and the dispersion medium coated with such a "protective dispersant having a short chain amine or an acid value" is not particularly limited and can be carried out according to a conventionally known method using a stirrer or a stirrer. It may be stirred with a spatula or the like, and an ultrasonic homogenizer of a suitable output may be exposed.

When obtaining the silver fine particle dispersion containing a some metal, it is not specifically limited as the manufacturing method, For example, when manufacturing silver fine particle dispersion which consists of silver and another metal, the metal coat | covered with the said organic substance In the preparation of the particles, a dispersion liquid containing silver fine particles and a dispersion liquid containing other metal particles may be separately prepared and then mixed, and the silver ion solution and the other metal ion solution are mixed and then reduced. You may also

A first step of adjusting a mixed liquid of a silver compound capable of producing metal silver by decomposition by reduction, and a short chain amine having a partition coefficient (logP) of -1.0 to 1.4; and reducing the silver compound in the mixed liquid to reduce the surface thereof. Silver microparticles | fine-particles may be manufactured by the 2nd process of producing the silver microparticles | fine-particles with a C5 or less short-chain amine attached to at least one part of the.

For example, oxalic acid containing silver is heated by heating a complex compound formed from a metal compound such as silver and a short chain amine, and aggregating the silver in an atomic state generated by decomposing a metal compound such as oxalate ion contained in the complex compound. Silver particles protected by a protective film of amine can be produced.

As described above, in the metal amine complex decomposition method in which a metal compound complex is thermally decomposed in the presence of an amine, a metal amine complex decomposition method for producing a metal particle coated with an amine generates an atomic metal by a decomposition reaction of a metal amine complex as a single molecule. Therefore, it is possible to uniformly form an atomic metal in the reaction system, and the reaction is nonuniform due to the unstable composition of the components constituting the reaction as compared with the case of generating metal atoms by the reaction between a plurality of components. This is suppressed, and is particularly advantageous when producing a large amount of metal powder on an industrial scale.

In the metal amine complex decomposition method, it is assumed that the short-chain amine molecule coordinates to the metal atom to be produced, and the motion of the metal atom at the time of causing aggregation is controlled by the function of the short-chain amine molecule coordinated to the metal atom. . As a result, according to the metal amine complex decomposition method, it becomes possible to manufacture metal particles which are very fine and have a narrow particle size distribution.

In addition, many short-chain amine molecules also cause coordination of relatively weak forces on the surface of the metal fine particles to be produced, and since they form a dense protective film on the surface of the metal particles, a clean coated metal particle having excellent storage stability is produced. It becomes possible. Moreover, since the short-chain amine molecule which forms the said film can be easily detached by heating etc., it becomes possible to manufacture the metal particle which can be sintered at very low temperature.

In addition, when a complex metal such as a complex compound is formed by mixing a solid metal compound with an amine, a short chain amine having 5 or less carbon atoms is mixed and used with a dispersant having an acid value constituting the coating silver coated film. The complex compound can be easily produced, and the complex compound can be produced by short mixing. Moreover, by mixing and using the said short chain amine, manufacture of the coated silver particle which has the characteristic according to various uses is possible.

(3) Conductive film pattern (base material with conductive film pattern) and its manufacturing method

When the transfer printing conductive ink of the present embodiment is used, the conductive ink coating step of applying the transfer printing conductive ink to the base material and the transfer printing conductive ink applied to the base material have a temperature of 200 ° C. or less (preferably 180 ° C.). With a conductive film pattern comprising a substrate and a conductive film pattern formed on at least a part of the surface of the substrate by a conductive film pattern forming step of baking at a temperature of less than, more preferably 150 ° C. or less) to form a conductive film pattern. Substrates can be prepared.

MEANS TO SOLVE THE PROBLEM As a result of intensive examination, this inventor apply | coats to the said base material in the conductive film pattern formation process, when the conductive ink for transfer printing of this embodiment mentioned above is used as the conductive ink in the said conductive ink coating process for transfer printing. Even if the said conductive ink was baked at the temperature of 200 degrees C or less, it discovered that the conductive film pattern which has the outstanding electroconductivity was obtained reliably.

In the reverse printing method of the transfer printing method, first, the conductive ink for transfer printing is coated on the blanket to form a conductive ink coating surface. As a blanket, the silicon blanket which consists of silicon is preferable. After the conductive ink coating surface is formed on the surface of the blanket and left for a predetermined time, the low boiling point solvent is absorbed in the volatilization and the blanket to increase the viscosity of the conductive ink for transfer printing.

When the convex plate in which the plate according to a predetermined pattern is formed on the said conductive ink application surface is pressed, the conductive ink of the part which contacts the said convex plate is removed from the blanket. At this time, when the conductive ink has a moderate cohesiveness, the conductive ink is not broken, the peeling from the blanket and the attachment to the convex plate are reliably performed, and undesired retention on the blanket is suppressed. As a result, the pattern of the conductive ink corresponding to the pattern of the convex plate is formed on the blanket by the conductive ink remaining on the blanket.

The conductive ink in the wet or semi-dry state left on the blanket is transferred to the printed object. At this time, since an electroconductive ink has moderate cohesion, peeling from a blanket and adhesion to a to-be-printed body are performed reliably, and undesirable residual to a blanket is suppressed. As a result, the electrically conductive film pattern is formed in the to-be-printed object by the pattern inverted with respect to the pattern formed in the convex board.

The substrate that can be used in the present embodiment is not particularly limited as long as it has at least one main surface capable of applying a conductive ink and firing by heating to mount the conductive film pattern, but it is preferably a substrate having excellent heat resistance. Do. Moreover, as mentioned above, since the conductive ink for transfer printing of this embodiment can obtain the electrically conductive film pattern which has sufficient electroconductivity even if it heats and bakes at low temperature compared with the conventional conductive ink, it is lower than this low baking temperature. In the high temperature range, it is possible to use a substrate having a lower heat resistance temperature than before.

As a material which comprises such a base material, for example, polyamide (PA), polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate Polyester, such as (PEN), polycarbonate (PC), polyether sulfone (PES), a vinyl resin, a fluororesin, a liquid crystal polymer, ceramics, glass, a metal, etc. are mentioned. Moreover, the base material may be various shapes, such as plate shape or strip shape, for example, and may be rigid or flexible. The thickness of a base material can also be selected suitably. For the purpose of improving the adhesiveness or adhesiveness or for other purposes, a substrate having a surface treatment such as a substrate having a surface layer or a hydrophilization treatment may be used.

The coating film after apply | coating as mentioned above is baked by heating at the temperature of 200 degrees C or less (preferably less than 180 degrees C, more preferably 150 degrees C or less), and it bakes, and the electrically conductive film pattern (base material with a conductive film pattern) of this embodiment Can be obtained.

The method of performing the said baking is not specifically limited, For example, using the conventionally well-known gear oven etc., the temperature of the said conductive ink apply | coated or drawn on the base material is 200 degrees C or less (preferably less than 180 degreeC, more preferable). For example, the conductive film pattern can be formed by firing so as to be 150 ° C or less). The lower limit of the firing temperature is not necessarily limited, and is a temperature at which a conductive film pattern can be formed on a substrate, and the organic component and the like can be removed by evaporation or decomposition within a range that does not impair the effects of the present invention. It is preferable that it is temperature (some may remain in the range which does not impair the effect of this invention, but it is preferable to remove all preferably).

According to the conductive ink of this embodiment, since the conductive film pattern which expresses high electroconductivity can be formed also in the low temperature heat processing of about 120 degreeC, a conductive film pattern can be formed also on the base material comparatively weak to heat. Moreover, baking time is not specifically limited, A conductive film pattern can be formed on a base material according to baking temperature.

In this embodiment, in order to further improve the adhesiveness of the said base material and a conductive film pattern, you may surface-treat the said base material. As said surface treatment method, the method of performing dry processing, such as a corona treatment, a plasma treatment, UV treatment, an electron beam treatment, the method of forming a primer layer, a conductive ink receiving layer on a base material previously, etc. are mentioned, for example.

In this manner, the conductive film pattern (conductive film pattern base material) of the present embodiment can be obtained. The conductive film pattern of this embodiment obtained in this way is about 0.1-5 micrometers, for example, More preferably, it is 0.1-1 micrometer. By using the conductive ink of the present embodiment, even if the thickness is about 0.1 to 5 µm, a conductive film pattern having sufficient conductivity can be obtained. In addition, the volume resistance value of the electrically conductive film pattern of this embodiment is 15 microohm * cm or less.

On the other hand, the thickness t of the conductive film pattern of this embodiment can be calculated | required, for example using the following formula (The thickness t of a conductive film pattern is a laser microscope (for example, a laser microscope made from Keyence). Measurement with VK-9510).

Expression: t = m / (d × M × w)

m ： Conductive film pattern weight (measure the weight of the conductive film pattern formed on the slide glass by electronic balance)

d: conductive film pattern density (g / cm 3) (10.5 g / cm 3 for silver)

M: conductive film pattern length (cm) (the length of the conductive film pattern formed on the slide glass is measured by the scale equivalent to JIS1 grade)

w: Conductive film pattern width (cm) (The width | variety of the conductive film pattern formed on the slide glass is measured by the scale equivalent to JIS1 grade.)

Example

Hereinafter, although an Example and a comparative example are further demonstrated about the conductive ink for transfer printing of this invention, and the manufacturing method of the conductive film pattern (conductive film pattern base material) using the said conductive ink, this invention is not the same as these Examples. It is not limited.

<< preparation 1 >>

8.9 g of 3-methoxypropylamine (the first grade of reagent made by Wako Pure Chemical Industries, Ltd., carbon number: 4, logP: -0.5) and 0.3 g of the DISPERBYK-111 which is a polymer dispersant are mixed, and a magnetic It stirred well with the stirrer and produced the amine liquid mixture (molar ratio of the added amine was 10 with respect to silver). Next, 3.0 g of oxalic acid was added, stirring. After the addition of the silver oxalate, stirring was continued at room temperature to change the silver oxalate to a viscous white substance, visually confirming that the change was apparently finished, and stirring was terminated at that time. 1 former process).

The obtained liquid mixture was transferred to the oil bath, and it heated and stirred at 120 degreeC. Immediately after the start of the stirring, a reaction involving the generation of carbon dioxide is started, and then stirring is performed until the generation of carbon dioxide is completed, thereby obtaining a suspension in which silver fine particles are suspended in the amine mixture (second step).

Next, in order to replace the dispersion medium of the obtained suspension, after stirring and adding 10 mL of methanol / water mixed solvents, silver fine particles were precipitated and separated by centrifugation. 10 mL of methanol / water mixed solvent was further added to the separated silver fine particles, followed by stirring, and the silver fine particles were precipitated by centrifugation to separate them. Ethanol / isobutanol / isopropyl alcohol (40: 40: 20v) was used as a dispersion solvent. / V) The silver fine particle dispersion A of 48 mass% of solid content concentration was obtained by adding 2.1 g of mixed solvents.

<< preparation 2 >>

8.9 g of 3-methoxypropylamine (a first grade reagent manufactured by Wako Pure Chemical Industries, Ltd., carbon number: 4, logP: -0.5) and 0.3 g of DISPERBYK-102, a polymer dispersant, are mixed and stirred well with a magnetic stirrer. To produce an amine mixture (the molar ratio of the added amine was 5 to silver). Then, 3.0 g of oxalic acid was added while stirring. After the addition of the silver oxalate, stirring was continued at room temperature to change the silver oxalate to a viscous white substance, visually confirming that the change was apparently finished, and stirring was terminated at that time. 1 former process).

The obtained liquid mixture was moved to the oil bath, and it heated and stirred at 120 degreeC. Immediately after the start of the stirring, a reaction involving the generation of carbon dioxide is started, and then stirring is performed until the generation of carbon dioxide is completed, thereby obtaining a suspension in which silver fine particles are suspended in the amine mixture (second step).

Next, in order to replace the dispersion medium of the obtained suspension, after stirring and adding 10 mL of methanol / water mixed solvents, silver fine particles were precipitated and separated by centrifugation. To the separated silver fine particles, 10 mL of a methanol / water mixed solvent was further added and stirred, followed by separation of silver fine particles by centrifugation, followed by separation, and ethanol containing 0.06 g of SOLSPERSE 41000 (manufactured by Japan Lubrizol). Silver fine particle dispersion B of 48 mass% of solid content concentration was obtained by adding 2.1 g.

Examples and Comparative Examples

It is mixed with the other components shown in Table 1 using the silver fine particle dispersion A or B obtained as mentioned above, and the electroconductive for comparative transfer printing of the electroconductive inks 1-7 for comparative transfer printing of Examples 1-7 and Comparative Examples 1-3. Inks 1-3 were prepared. In addition, the unit of the quantity of the component in Table 1 was made into the "mass%."

Moreover, the following evaluation tests were done about said silver fine particle dispersions A and B, the electroconductive inks 1-7 for conducting transfer printing, and the electroconductive inks 1-3 for comparative transfer printing. The results are shown in Table 1.

[Evaluation test]

(1) organic component measurement

The content of the organic component contained in the silver fine particle dispersion was measured by thermogravimetric analysis. Specifically, solid content of silver fine particle dispersion was heated at the temperature increase rate of 10 degree-C / min, and content of the organic component was identified as the weight decreasing amount of room temperature-500 degreeC.

(2) dispersibility

The electroconductive ink for transfer printing was left still in a container, and after 1 day of room temperature, the dispersibility of the silver fine particle dispersion was evaluated by visually observing the presence or absence of precipitation and the supernatant state. The case where "(circle)" and the case where a small amount of sediment was seen in the case where hardly a sediment was seen under a container showed the difference of density clearly in "(triangle | delta)" and the upper and lower sides of a container, and evaluated the case where a sediment was clearly seen by "x".

(3) Measurement of surface tension of conductive ink

The surface tensions of the conductive inks 1 to 4 for the transfer printing obtained in Examples 1 to 4 and the conductive inks 1 to 3 for the comparative transfer printing obtained in Comparative Examples 1 to 3 were calculated using the fully automatic surface tension meter CBVP-Z (Kyowakaimen Kagaku). It was measured by the corporation. The measurement was carried out by automatic measurement using a platinum plate. Measurement temperature was made into normal temperature (20-25 degreeC).

(4) Evaluation of the wettability of the conductive ink

Application | coating with the bar coater (No. 7) on the silicone blanket using the conductive transfer ink 1-7 of the implementation transfer printing obtained in Examples 1-7, and the conductive ink 1-3 of the comparative transfer printing obtained in Comparative Examples 1-3. The wettability of the conductive ink for transfer printing on the blanket was visually evaluated. When wettability was favorable, it evaluated as "(circle)", and when it was a defect, "x".

(5) Evaluation of Print Shape (Fine Line Drawability)

The glass convex plate was pressed on the blanket which apply | coated the conductive ink for transfer printing, and the non-image part (unnecessary part) was transferred and removed. In addition, the pattern was transferred to the substrate by pressing the substrate (PEN: polyethylene naphthalate) on the blanket material. The print shape was evaluated by visually observing the obtained pattern shape. When a print shape was favorable, it evaluated as "(circle)", the case of an allowable range with "(triangle | delta)", and the case of defect with "x". The pattern was made into thin lines, and the line width was 10, 20, 30, 50, 100 micrometers, and length 10mm.

(6) evaluation of transferability

Transferability was evaluated by visually evaluating the printing shape formed in said (5) and the electroconductive ink which remained on the blanket. When the print shape was good and hardly remained on the blanket, it was "(circle)", in the case of a permissible range, "△", and when the print shape was bad or remained clearly on the blanket, it was set as "x".

(7) evaluation of continuous printability

Continuous printability was evaluated by repeating the layer of evaluation of the print shape of said (5) five times continuously.

(8) Evaluation of conductivity of conductive film pattern

The pattern (line width 100 micrometers, length 10mm) transferred to the base material was baked on 120 degreeC x 30 minute conditions, and the resistance value of the pattern was measured. Specifically, the volume resistivity was calculated | required by the double bridge method using the portable double bridge 2769 by Yokogawa & Instruments Co., Ltd. Based on the following formula, the volume resistance value was converted from the distance between the measurement terminals, and the thickness of the conductive film pattern.

Expression: Volume Resistivity (ρｖ) =

Resistance value (R) x coating width (w) x coating thickness (t) / distance between terminals (L)

TABLE 1

In addition, in Table 1, it is made from "Novec7300" Sumitomo 3M, and "Surfron S-651" is a chemical agent made by AGC. In addition, "putagent 610 FM" is a product made by Neos.

As is clear from the results shown in Table 1, it can be seen that the conductive ink for transfer printing of the present invention is excellent in dispersibility, wettability, printability, and conductivity. Especially, Example 3 and 4 using the silver fine particle dispersion B are excellent also in continuous printability, and are especially preferable.

On the other hand, the comparative examples 1 and 2 show that the electroconductive ink which does not contain the specific high boiling point solvent is inferior to transferability. Moreover, according to the comparative example 3, when content of a high boiling point solvent is excess, it turns out that drying is inferior and transferability is inferior. Moreover, even if it contains only a fluorine solvent by the comparative example 2, although wettability can be ensured, it turns out that transferability is inferior.

Claims (6)

With silver particles,
A solvent containing ethanol,
0.4-1.0 mass% of 1, 3- butylene glycol which has a hydroxyl group, and is a high boiling point solvent which has a boiling point in 1 atmosphere of 200 degreeC or more,
A dispersant having an acid value for dispersing the silver fine particles,
A silver fine particles dispersion containing silver fine particles, a short chain amine having a carbon number of 5 or less and a distribution coefficient (logP) of -1.0 to 1.4, and a high polar solvent having an SP value (dissolution parameter) of 7.0 to 15.0.
The conductive ink for transfer printing characterized by the above-mentioned. The method of claim 1,
The said fine particle dispersion WHEREIN: The said short-chain amine is an alkoxy amine, and further includes the protective dispersing agent which has an acid value, The electroconductive ink for transfer printing characterized by the above-mentioned. The method according to claim 1 or 2,
A conductive ink for transfer printing, further comprising hydrofluoroether. The method of claim 2,
The acid value of the said protective dispersing agent is 5-200, and has a functional group derived from phosphoric acid, The electroconductive ink for transfer printing characterized by the above-mentioned. delete delete