JP6287611B2 - Silver film forming composition, silver film, wiring board, electronic device, and method for producing silver particles - Google Patents

Description

  The present invention relates to a composition for forming a silver film, a silver film, a wiring board, an electronic device, and a method for producing silver particles.

  The wiring board is also referred to as a printed wiring board or the like, and has become a major component for fixing and wiring electronic components in the field of electronic equipment. In this wiring substrate, a patterned metal film is formed on the substrate to constitute wiring, electrodes, terminals, and the like. In the field of electronic equipment, similarly to a printed wiring board, there are a touch panel, a liquid crystal display element, an organic EL element, and the like that form a patterned metal film on a substrate and use them as wirings.

  In the case of manufacturing a wiring board, as a method for forming a pattern such as a wiring that is a metal film on the board, for example, a method using a photolithography technique is known. In this method, first, a uniform solid metal film is formed on a substrate. As a method for forming the metal film, for example, a plating method is used. Further, it is possible to use vapor deposition or sputtering. Then, a resist solution is applied on the formed metal film to form a resist layer. Next, the resist layer is patterned by irradiating the resist layer with ultraviolet rays or the like using a photomask and then developing the resist layer. Next, the metal film not covered with the resist layer is removed by etching, and the remaining resist portion is peeled off to obtain a patterned metal film. The method using the photolithography technique can make the line width of the formed wiring pattern on the order of submicron, and is an effective method for forming a metal film pattern.

In the method using such a photolithography technique, as described above, a plating method is used to form a metal film to be patterned. In the plating method, formation of a seed layer by a sputtering method and a plating process are usually required. Since the sputtering method needs to be performed in a vacuum, there are significant restrictions on the apparatus and operation. Also, the process takes a long time and the production efficiency is low. In the plating process of the plating method, the waste liquid treatment of the plating solution becomes a big environmental problem.
Similarly, when using a vapor deposition method, sputtering method, or the like for forming a metal film, it is necessary to form the metal film in a vacuum. Therefore, a metal film cannot be formed efficiently and simply.

  Therefore, there is a demand for a metal film forming technique that can be easily formed in a short time with a low resistance metal film with few restrictions on the apparatus and the environment. The metal film formation technique is a technique capable of forming a uniform solid metal film on a substrate, and a technique capable of directly forming a patterned metal film. It is preferable.

  Therefore, in recent years, attention has been paid to a technique for directly drawing a patterned metal film using a dispersion composition obtained by dispersing metal fine particles in an organic solvent or the like. For example, using a dispersion composition of metal fine particles, a desired coating film pattern is formed by an ink jet printing method or a screen printing method. When the average particle diameter of the metal fine particles is about several nanometers to several tens of nanometers, that is, several nanometers to several tens of nanometers, the melting point is lower than that of the bulk metal, and the particles are heated by relatively low temperature below 300 ° C. Fusion occurs. The above-described technique utilizes such a phenomenon, and heats the pattern of the coating film at a relatively low temperature to sinter the contained metal fine particles to obtain a patterned metal film.

  Silver particles are known as fine metal particles used in such a dispersion composition for forming a metal film. In the present invention, the silver particle is a metal fine particle made of silver or a metal fine particle containing silver, and is a concept including what is also called a silver nanoparticle or a silver-containing nanoparticle.

  On the other hand, metal fine particles are attracting attention when bonding electronic members or ceramics.

  For example, in a semiconductor device such as a power module, a method is generally employed in which elements are bonded to a substrate on which a circuit is formed via a conductive bonding material. Conventionally, a solder material has been widely applied as the bonding material, and as the solder material, an alloy having mainly a tin as a main component and a low melting point is generally used. However, in applications where a high-temperature use environment is applied, there is a problem that when a solder material is applied as a bonding material, a part thereof is melted and peeled off.

  In recent years, due to environmental concerns and toxicity concerns, solders that do not contain lead components, so-called lead-free solders, are often used. However, the generation of whiskers suppressed by the blending of the lead component and the decrease in reliability due to this have been regarded as problems, and an alternative material has been desired.

  On the other hand, in the bonding of ceramic materials, a material that exhibits stable bonding performance in a harsh environment such as a high temperature expected for ceramic materials, and at the same time, a material capable of low-temperature process conditions is expected.

  In response to these demands, metal particles exhibit high bonding performance by fusing each other at a low temperature of 300 ° C. or lower, and at the same time, a bonded portion ideally exhibits bonding ability up to the melting point of the metal. become. For example, the melting point when silver is used is 1235K (Kelvin). In addition, by realizing bonding with a metal layer that does not depend on an organic binder or the like, it is possible to provide high conductivity and heat dissipation functions.

  As a dispersion composition containing silver particles, a method for producing silver particles suitable for forming a metal film such as a low-resistance silver film has been actively studied so that the above-described applications can be used. Studies on the preparation of products have been actively conducted.

  For example, Patent Document 1 describes a method in which silver oxalate, alkylamine, and dialkylamine are mixed and heated, and silver nanoparticles are produced by thermal decomposition.

  Patent Document 2 describes a method of producing silver nanoparticles by a reduction reaction in a liquid phase by mixing silver oxide, formic acid and an amine.

  Patent Document 3 describes a method for producing silver nanoparticles by mixing a silver compound and a branched aliphatic amine compound that is a stabilizer, and adding a reducing agent thereto, A silver coating composition obtained by dispersing the obtained silver nanoparticles in an organic solvent is described.

JP 2010-265543 A JP 2011-153362 A JP 2012-246560 A

  As described above, for example, a metal film forming technique capable of efficiently and simply forming a low-resistance metal film such as a silver film is required so as to be suitable for manufacturing a wiring board. The metal film formation technique is a technique capable of forming a uniform metal film on one surface of a substrate, and a technique capable of directly forming a metal film patterned into a desired shape. It is preferable that For this reason, as described above, active investigations have been made on the method for producing fine metal particles such as silver-containing nanoparticles and the preparation of a composition such as a silver film-forming composition containing the same. However, each technology has problems to be solved.

  For example, in the case of the method for producing silver particles described in Patent Document 1 described above, silver oxalate is used as a raw material. However, silver oxalate is known to have explosive properties, and ensuring safety during mass production is an issue.

  Also, in the case of a technique for forming a metal film using a composition containing metal fine particles, the metal film obtained after sintering can achieve electrical resistance characteristics compared to bulk metal, that is, low resistance. There was a problem that it was difficult. This is because it is difficult to completely fuse the metal fine particles by simple sintering at a low temperature.

  For example, the method for producing silver particles described in Patent Document 2 described above includes a step of preparing a dispersion of powdered silver formate by allowing excess formic acid to act on the raw material silver oxide, and the powdered silver formate dispersion. An excess of primary amine is allowed to act to form a primary amine complex of silver formate, the primary amine complex of silver formate is dissolved in a chain hydrocarbon solvent, and then the primary amine complex of silver formate is decomposed. A method for producing silver nanoparticles by a catalytic reduction reaction is disclosed. However, the powdered silver formate produced during the process of the above-mentioned method has been pointed out to have a sharp explosion sensitivity and a large heat of decomposition, and since it is insoluble, it is prone to stagnation and accumulation. There is a problem in ensuring safety. Furthermore, it is described that the primary amine added excessively causes a neutralization reaction with the remaining formic acid without being consumed, resulting in an increase in the liquid temperature. When the exothermic heat of the reaction is intense, it is difficult to control the reaction to form silver particles under the influence. As a result, the particle diameter of the silver particles to be produced varies, which causes a quality problem. In particular, when the particle size varies, there is a problem that it becomes difficult to fuse the silver particles by simple low-temperature sintering, and the resistance of the resulting silver film cannot be reduced.

  As described above, for example, the production technology of silver particles and the production technology of a composition for forming a silver film containing the same are suitable for the production of a metal film of a wiring board, as well as safety in mass production and simplicity. There is also a demand for a low resistance metal film formed using the same. However, it has been difficult for the conventional techniques to satisfy them all.

  Therefore, a technique for easily producing silver particles using a safe material is required.

  Further, there is a demand for a technique for producing silver particles having desired quality by controlling a desired reaction, and silver particles having a desired quality are desired.

  And the composition for silver film formation containing the silver particle of the desired quality is calculated | required, The formation technique of the silver film which can form a low resistance silver film and it is calculated | required. Furthermore, there is a need for a wiring board that is formed simply and has a low-resistance silver film, and an electronic device having the wiring board.

  The present invention has been made based on the above findings. That is, the objective of this invention is providing the manufacturing method of the silver particle which manufactures the silver particle excellent in quality simply.

  Moreover, the objective of this invention is providing the composition for silver film formation containing the silver particle excellent in quality.

  Another object of the present invention is to provide a silver film that is easily formed and has a low resistance.

  Another object of the present invention is to provide a wiring board having a low resistance silver film that is easily formed.

  Furthermore, the objective of this invention is providing the electronic device provided with the wiring board which is formed easily and has a low resistance silver film.

  Other objects and advantages of the present invention will become apparent from the following description.

The first aspect of the present invention is:
(A) Silver particle obtained by mixing monocarboxylic acid amine salt and silver oxide, and (B) Alcohol whose boiling point is 150 degreeC-250 degreeC, It is related with the composition for silver film formation characterized by the above-mentioned.

In the first aspect of the present invention, the silver particles are
(1) forming a salt using a monocarboxylic acid and an amine compound;
(2) It is preferable that it is a silver particle obtained through the process of adding the said salt to the mixture containing silver oxide (I).

  In the first embodiment of the present invention, the average particle diameter of the silver particles is 5 nanometers (nm) or more and 80 nanometers (nm) or less, that is, in the range of 5 nanometers (nm) to 80 nanometers (nm). It is preferable.

  In the first aspect of the present invention, the monocarboxylic acid amine salt is selected from the group consisting of formic acid, acetic acid, trifluoroacetic acid, propionic acid, butanoic acid, isobutanoic acid, pentanoic acid, 2-methylbutyric acid, pivalic acid and hydroxyacetic acid. It is preferably an amine salt of at least one monocarboxylic acid selected.

  1st aspect of this invention WHEREIN: It is preferable that (B) alcohol whose boiling point is 150 to 250 degreeC is alcohol which has an alicyclic hydrocarbon structure.

  A second aspect of the present invention relates to a silver film formed using the silver film forming composition according to the first aspect of the present invention.

  According to a third aspect of the present invention, there is provided a wiring board comprising the silver film according to the second aspect of the present invention.

  A 4th aspect of this invention is related with the electronic device provided with the wiring board of the 3rd aspect of this invention.

  A fifth aspect of the present invention relates to a method for producing silver particles, characterized in that a monocarboxylic acid amine salt and silver oxide are mixed to produce silver particles used in a composition for forming a silver film.

  According to the 1st aspect of this invention, the composition for silver film formation containing the silver particle excellent in quality is provided.

  According to the second aspect of the present invention, a low-resistance silver film that is easily formed is provided.

  According to the 3rd aspect of this invention, the wiring board which is formed simply and has a low resistance silver film is provided.

  According to the 4th aspect of this invention, the electronic device provided with the wiring board which has a low resistance silver film is provided.

  According to the 5th aspect of this invention, the manufacturing method of the silver particle which manufactures the silver particle excellent in quality simply is provided.

It is a top view which shows the touchscreen of embodiment of this invention. It is sectional drawing which follows the B-B 'line of FIG.

  In the present invention, a silver compound such as silver (I) that is easily available and highly safe is used as a raw material for producing silver particles. In addition, a monocarboxylic acid and an amine compound that are easily available and highly safe are used.

  And the 1st process of forming a salt using monocarboxylic acid and an amine compound, and the 2nd process of adding the salt formed at the 1st process to the mixture containing silver oxide (I), Are provided separately and combined to produce the silver particles of the present invention.

  In the second step, a monocarboxylic acid amine salt which is a salt of a monocarboxylic acid and an amine compound is allowed to act on silver oxide (I) to reduce the silver oxide (I), thereby producing metallic silver. Silver particles are produced.

  As a result, in the present invention, silver particles can be produced by using a step of forming a salt of a monocarboxylic acid and an amine compound (monocarboxylic acid amine salt) and a step of forming silver particles as separate steps. Therefore, it can control that the heat of neutralization of the monocarboxylic acid and amine compound generated in the first step affects the formation of silver particles in the second step. In other words, silver particles can be produced by controlling the effect of heat of neutralization of formic acid and amine compound to be low, and silver particles having a uniform and desired size can be produced.

  For example, when formic acid or oxalic acid is used as the monocarboxylic acid, according to the method for producing silver particles of the present invention, the silver or silver oxalate that has a high risk of explosion does not pass through silver formate or oxalate. Particles can be produced. In other words, the reaction of silver oxide with a salt of formic acid and an amine compound can lead to an intermediate compound with higher solubility and lower risk of explosion. It can be manufactured by a highly efficient method.

  Further, in the present invention, the silver particles thus produced are used as a dispersion formed by dispersing silver particles in other components, for example, alcohol having a boiling point of 150 ° C. to 250 ° C. described later. A silver film-forming composition can be produced.

  And in this invention, the silver film formation composition can be apply | coated on a board | substrate, for example, a coating film can be formed, the coating film can be heated, and a silver film can be formed.

  The composition for forming a silver film of the present invention can form a silver film as a uniform solid metal film on a substrate, and when combined with an appropriate coating method, becomes a wiring, electrode, terminal, etc. It is also possible to form a patterned silver film directly on the substrate. Therefore, in the present invention, the “silver film” is a concept including a patterned silver film together with a solid film containing silver. That is, patterns such as silver wiring and silver electrodes are also included in the “silver film” of the present invention. Similarly, the “film” may be used as a concept including a pattern.

  In the present invention, the “wiring board” is not limited to the wiring board known as a so-called printed wiring board. In the present invention, the “wiring substrate” includes all substrates in which a patterned metal film is formed on the substrate to form wirings, electrodes, terminals, and the like. For example, in the present invention, the “wiring board” includes a board for constituting a touch panel, a liquid crystal display element, an organic EL element and the like in addition to the above-described printed wiring board. That is, the “wiring substrate” of the present invention includes a substrate in which a patterned metal film is formed on the substrate to form wirings, electrodes, terminals, and the like.

  Furthermore, in the present invention, the “wiring substrate” includes those in which a patterned metal film is formed on the inner surface or the outer surface of a housing such as an electronic device to constitute wiring, electrodes, terminals, and the like.

  In the present invention, hereinafter, for the sake of convenience, conductive electrically conductive members referred to as wirings, electrodes, terminals, and the like of the wiring board are collectively referred to as wirings.

  Below, the manufacturing method of the silver particle of embodiment of this invention and the silver particle manufactured by it are demonstrated in detail. And the preparation of the composition for silver film formation of the embodiment of the present invention including the silver particles of the embodiment of the present invention produced, the silver film of the embodiment of the present invention formed using the same, and the silver A wiring board and an electronic device having a film will be described.

<Method for producing silver particles and silver particles>
The silver particle production method according to an embodiment of the present invention includes a first step of forming a salt using a monocarboxylic acid and an amine compound, and the salt formed in the first step is converted into silver oxide (I And a second step of adding to the mixture containing. Hereinafter, each process etc. are demonstrated.

[First step]
The 1st process which the manufacturing method of the silver particle which is embodiment of this invention has is a process of forming those salts using monocarboxylic acid and an amine compound.

  In the first step, the amine compound and the monocarboxylic acid are mixed, for example, by dropping a monocarboxylic acid into the amine compound stirred in the reaction vessel. Then, the monocarboxylic acid and the amine compound are reacted to form a salt thereof, that is, a monocarboxylic acid amine salt. At this time, it is preferable to cool the reaction vessel using an ice bath or the like and carry out the monocarboxylic acid amine salt formation reaction while suppressing the heat of neutralization.

  Monocarboxylic acids preferably used in the first step include formic acid, acetic acid, trifluoroacetic acid, propionic acid, butanoic acid, isobutanoic acid, pentanoic acid, 2-methylbutyric acid, pivalic acid and hydroxyacetic acid.

  A particularly preferred monocarboxylic acid is formic acid.

  The formic acid used in the first step can be a commercially available product, and the obtaining method and the like are not particularly limited.

  Further, the purity of formic acid used in the first step is not particularly limited. However, when the purity is low, there is a concern that the conductivity is lowered when the silver film is formed using the formed silver particles. Therefore, the purity of formic acid is preferably 95% or more, and more preferably 99% or more.

  Examples of amine compounds that can be used in the first step include ethylamine, n-propylamine, i-propylamine, n-butylamine, i-butylamine, t-butylamine, n-pentylamine, and n-hexylamine. Cyclohexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, 2-ethylhexylpropylamine, 3-ethoxypropylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, Monoamine compounds such as n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, benzylamine, aminoacetaldehyde diethyl acetal, ethylenediamine, N-methylethylenediamine, N, N′-dimethyl Ruethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N-ethylethylenediamine, N, N′-diethylethylenediamine, 1,3-propanediamine, N, N′-dimethyl-1,3-propanediamine 1,4-butanediamine, N, N′-dimethyl-1,4-butanediamine, 1,5-pentanediamine, N, N′-dimethyl-1,5-pentanediamine, 1,6-hexanediamine, Diamine compounds such as N, N′-dimethyl-1,6-hexanediamine, isophoronediamine, diethylenetriamine, N, N, N ′, N ″ N ″ -pentamethyldiethylenetriamine, N- (aminoethyl) piperazine, N And triamine compounds such as-(aminopropyl) piperazine.

  In the first step, the mixing ratio of the monocarboxylic acid and the amine compound is preferably a ratio in which the amine compound is 1 to 20 moles per mole of the monocarboxylic acid. By setting it as such a compounding ratio, the salt of the desired monocarboxylic acid and an amine compound can be formed efficiently.

[Second step]
In the second step of the method for producing silver particles according to the embodiment of the present invention, the monocarboxylic acid amine salt formed in the first step described above is added to a mixture containing silver (I) and silver oxide. This is a step of producing silver particles by reducing (I).

  In the second step, first, silver oxide and an amine compound are added to a reaction vessel, and the mixture is stirred and mixed to prepare a silver oxide dispersion as a mixture containing silver (I).

  Silver (I) oxide used in the second step is a starting material in the production of silver particles, but the purity thereof is not particularly limited. However, when the purity is low, there is a concern that the conductivity is lowered when the silver film is formed using the formed silver particles. Therefore, the purity of silver (I) is preferably 95% or more, and more preferably 99% or more.

  Examples of amine compounds that can be used in the second step include ethylamine, n-propylamine, i-propylamine, n-butylamine, i-butylamine, t-butylamine, n-pentylamine, and n-hexylamine. Cyclohexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, 3-ethoxypropylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, Monoamine compounds such as n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, benzylamine, aminoacetaldehyde diethyl acetal, diethylamine, triethylamine, 3- (2-ethylhexyloxy) propylamine, ethylenedia N-methylethylenediamine, N, N′-dimethylethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N-ethylethylenediamine, N, N′-diethylethylenediamine, 1,3-propanediamine, N , N′-dimethyl-1,3-propanediamine, 1,4-butanediamine, N, N′-dimethyl-1,4-butanediamine, 1,5-pentanediamine, N, N′-dimethyl-1, Diamine compounds such as 5-pentanediamine, 1,6-hexanediamine, N, N′-dimethyl-1,6-hexanediamine, isophoronediamine, diethylenetriamine, N, N, N ′, N ″ N ″ -penta Triamids such as methyldiethylenetriamine, N- (aminoethyl) piperazine, N- (aminopropyl) piperazine Compounds, polyamine compounds such as polyethyleneimine.

  In the silver oxide dispersion, the content of the above-described amine compound is in the range of more than 1.8 moles and less than or equal to 8.0 moles per mole of silver atoms in silver (I). preferable. By setting it as such an orientation ratio, the reduction | restoration reaction of silver oxide (I) mentioned later advances efficiently, the dispersion | variation in the particle size of the silver particle obtained is suppressed, and a high quality silver particle is obtained.

  Next, in the second step, the monocarboxylic acid amine salt obtained in the first step is added as it is, for example, dropwise, while stirring to the prepared silver oxide dispersion. . Thereafter, when necessary, heating at the adjusted temperature is performed and stirring is performed to perform a reduction reaction of silver (I) oxide. Silver oxide (I) is reduced to form metallic silver, and as a result, silver particles are formed.

  At this time, in this embodiment, the reduction reaction of silver oxide (I) in the second step is less affected by the heat of neutralization during salt formation with the monocarboxylic acid and the amine compound. For example, even if the monocarboxylic acid is formic acid, it is rarely affected by the heat of neutralization during the formation of the formic acid amine salt by formic acid and an amine compound. Therefore, the reaction temperature can be easily controlled, and the particle size of the produced silver particles is small and uniform. That is, in the present embodiment, the produced silver particles are suppressed from variation in particle size.

  The silver particles of this embodiment are formed in a state of being dispersed in other liquid components in the reaction vessel. Therefore, for example, a highly polar solvent such as methanol is added to the silver particle dispersion, and stirring is stopped and the mixture is allowed to stand. Then, a precipitate containing silver particles can be obtained by separating the supernatant by a method such as decantation or centrifugation.

  The silver particles of the embodiment of the present invention produced by the separated first step and second step have an average particle size of 5 nanometers (nm) to 80 nm, desirably 7 nm to 40 nm, and its standard deviation Can be suppressed to 20 nanometers (nm) or less. Therefore, there is little variation in particle size, and when used for forming a silver film, a low-resistance silver film can be easily formed.

  In addition, as a measuring method of the particle size of silver particle, the measuring method applied to a general fine particle can be used. For example, a transmission electron microscope (TEM), a field emission transmission electron microscope (FE-TEM), a field emission scanning electron microscope (FE-SEM), or the like can be used as appropriate. The average particle size value is observed using the above-mentioned microscope, and three locations where the particle sizes are relatively uniform are selected from the observed field of view and photographed at a magnification most suitable for particle size measurement. . From each of the obtained photographs, select the 100 most likely particles, measure the diameter with a measuring instrument such as a ruler, and calculate the particle size by dividing the measurement magnification. Can be obtained by arithmetic averaging. The standard deviation can be obtained from the particle size and number of individual silver particles at the time of the above observation.

  Thus, the silver particles produced by the method for producing silver particles according to the embodiment of the present invention can be used in the state of the precipitate described above. It can use for preparation of the composition for silver film formation of embodiment.

<Composition for forming silver film>
The composition for silver film formation of embodiment of this invention contains the silver particle of embodiment of the above-mentioned this invention. Moreover, the composition for silver film formation of this embodiment can contain a solvent further, and can be used for formation of a silver film as a paste-like composition or an ink-like composition.

  The composition for forming a silver film of the present embodiment can contain other optional components described later in addition to the silver particles. The composition for forming a silver film of the present embodiment can form a patterned coating film by various known coating methods, and the coating film can be heated to form a silver film. it can. Hereinafter, components that can be contained in addition to silver particles in the composition for forming a silver film of the embodiment of the present invention will be described.

[solvent]
In the composition for forming a silver film of the present embodiment, a solvent can be added as a component. And it is preferable that the composition for silver film formation of this Embodiment contains a solvent. By including a solvent in the silver film-forming composition, it becomes easy to adjust the viscosity of the silver film-forming composition corresponding to the coating method, and it is possible to form a silver film having stable and uniform physical properties. Become.

  When the composition for silver film formation of this embodiment contains a solvent, content of a solvent is more than 0 mass% with respect to 100 mass% of all the components of the composition for silver film formation of this embodiment. The content in the range of up to mass% is possible, the content is preferably more than 0 mass% and 70 mass% or less, more preferably more than 0 mass% and 50 mass% or less.

  The solvent to be added is not particularly limited as long as each component in the composition for forming a silver film can be dissolved or dispersed. Examples thereof include one liquid selected from water, alcohols, ethers, esters, aliphatic hydrocarbons and aromatic hydrocarbons, or two or more compatible liquids.

  Regarding specific examples of the solvent, alcohols include methanol, ethanol, n-propyl alcohol (1-propanol), i-propyl alcohol, n-butyl alcohol (1-butanol), i-butyl alcohol, sec-butyl alcohol, Examples include pentanol, hexanol, heptanol, octanol, nonyl alcohol, decanol, cyclohexanol, benzyl alcohol, terpineol, dihydroterpineol and the like.

  Examples of ethers include hexyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n. -Propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, Tripropylene (Poly) alkylene glycol monoalkyl ethers such as monoethyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane.

  Examples of the esters include methyl formate, ethyl formate, butyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, and γ-butyrolactone.

  Examples of the aliphatic hydrocarbons include n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, tetradecane, cyclohexane, decalin and the like. It is done.

  Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, n-propylbenzene, i-propylbenzene, n-butylbenzene, mesitylene, chlorobenzene, dichlorobenzene, and the like.

  Of these organic solvents, ethers and alcohols are preferably selected from the viewpoint of easy adjustment of the viscosity of the silver film-forming composition.

  And as a solvent of the composition for silver film formation of this embodiment, the boiling point is 150 degreeC-250 degreeC so that the removal from a silver film may become easy in consideration of the heating temperature for silver film formation mentioned later. The selection of certain alcohols is more preferred. The alcohol having a boiling point of 150 ° C. to 250 ° C. is particularly preferably an alcohol having an alicyclic hydrocarbon structure.

[Other optional ingredients]
In addition to the silver particles of the embodiment of the present invention, the composition for forming a silver film of the embodiment of the present invention includes, as an optional component, a dispersant, an antioxidant, a concentration, as long as the effects of the present invention are not impaired. It is possible to contain an adjusting agent, a surface tension adjusting agent, a viscosity adjusting agent, a coating film forming auxiliary agent and the like. Further, other optional components such as a dispersant, an antioxidant, a concentration adjusting agent, a surface tension adjusting agent, and a viscosity adjusting agent are used together with the silver particles, and the silver film forming composition of the present embodiment has a desired component concentration. , And can be adjusted to have surface tension, viscosity, and the like.

[Preparation of composition for forming silver film]
When the composition for forming a silver film of the embodiment of the present invention contains the above-described solvent or the like in addition to the silver particles, it can be easily prepared and manufactured by mixing the silver particles and the solvent. . Moreover, when there are many kinds of components contained, the order in which each component is mixed is not particularly limited.

  The mixing method of each component in the preparation of the silver film-forming composition of the present embodiment is not particularly limited. For example, stirring with a stirring blade, stirring with a stirrer and a stirring bar, stirring with a boiling machine, Examples thereof include a method using a sonic homogenizer, a bead mill, a paint shaker, a stirring deaerator, or the like. As mixing conditions, for example, in the case of stirring with a stirring blade, the rotation speed of the stirring blade is usually in the range of 1 rpm to 4000 rpm, preferably in the range of 10 rpm to 2000 rpm.

<Silver film forming method and silver film>
The composition for forming a silver film of the embodiment of the present invention described above is applied to a desired appropriate substrate by an appropriate application method to form the coating film. And the coating film of the composition for silver film formation of this embodiment is heated, and forms a silver film on a board | substrate. That is, the silver film formation method of embodiment of this invention forms the silver film of embodiment of this invention using the composition for silver film formation of embodiment of this invention. As a result, the wiring board of the embodiment of the present invention including the silver film of the embodiment of the present invention can be manufactured.

  In the silver film forming method of the embodiment of the present invention, by heating the coating film of the composition for forming a silver film of the present embodiment applied on the substrate, the silver particles contained in the composition are fused. Causes wearing. And in the silver film formation method of this embodiment, silver particle can be sintered at comparatively low temperature, and the patterned silver film can be obtained.

  Therefore, the silver film forming method of the embodiment of the present invention includes (1) a step of forming a coating film of the composition for forming a silver film of the embodiment of the present invention on a substrate, which is a composition containing silver particles; (2) It preferably includes a step of heating the coating film on the substrate.

  Hereinafter, the silver film forming method of the embodiment of the present invention will be described in more detail.

[substrate]
In the silver film forming method of the embodiment of the present invention, a known substrate can be used as the substrate for forming the coating film of the silver film forming composition of the present embodiment, and is not particularly limited.

  Examples of the material constituting the substrate include resin, paper, metal, glass, and the like. More specifically, low-density polyethylene resin, high-density polyethylene resin, polypropylene resin, ABS resin (acrylonitrile-butadiene-styrene co-polymer). Polymerization resin), acrylic resin, styrene resin, vinyl chloride resin, epoxy resin, glass epoxy resin, polyimide resin, polyester resin (polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate), polyacetal Resin, resin base materials such as cellulose derivatives, uncoated printing paper, fine coated printing paper, coated printing paper (art paper, coated paper), special printing paper, copy paper (PPC paper), unbleached wrapping paper ( Kraft paper for heavy bags, Kraft paper), bleached wrapping paper (bleached kraft paper, pure white roll paper), paper substrates such as coated balls and chipboard corrugated cardboard, metal substrates such as copper plates, iron plates, aluminum plates, soda glass, borosilicate glass, silica Examples thereof include glass substrates such as glass and quartz glass, alumina, sapphire, zirconia, titania, yttrium oxide, and ITO (indium tin oxide).

[Coating method]
In the method for forming a silver film of the embodiment of the present invention, as a method for applying the composition for forming a silver film of the present embodiment, printing methods such as inkjet printing, gravure printing, flexographic printing, (silk) screen printing, and relief printing Is mentioned. Examples of the coating method include spin coating, spray coating, bar coating, casting, dip coating, potting, and roll coater. The coating amount for applying the silver film forming composition of the present embodiment to the substrate can be appropriately adjusted according to the desired film thickness of the silver film.

  The composition for forming a silver film of the present embodiment can be applied to the coating method described above. Therefore, in the silver film forming method of the embodiment of the present invention, the silver film of the present embodiment is formed by forming a uniform solid coating film on the substrate using the silver film forming composition of the present embodiment. Is possible.

  Furthermore, in the silver film forming method of the embodiment of the present invention, direct printing using an ink jet printing method, a gravure printing method, a gravure offset printing method, a reverse offset printing method, a flexographic printing method, a (silk) screen printing method, a relief printing, or the like. By drawing, a coating film of the composition for forming a silver film of the present embodiment patterned into a desired shape can be formed. As a result, the silver film forming method of the embodiment of the present invention can directly form a patterned silver film on the substrate, which becomes wiring, electrodes, terminals, and the like. As a result, the patterned silver film of the embodiment of the present invention can be formed on an appropriate substrate to provide the wiring substrate of the embodiment of the present invention.

  Furthermore, in the silver film forming method of the embodiment of the present invention, a coating film of the composition for forming a silver film of the present embodiment is formed on the substrate, electrode, terminal, element, wiring, and ceramic, and the substrate and the electrode are further stacked. , Terminals, elements, wirings, ceramics and the like can be laminated and joined. As such a laminated body, it is suitably used for a laminated body by joining an element and a substrate in a power module or an LED module, a laminated body by joining between ceramic materials, a laminated body by joining metal electrodes on a ceramic substrate, etc. Is done. Although it does not specifically limit regarding a ceramic, Alumina, silicon carbide, silicon nitride, zirconia, barium titanate, a ferrite, etc. can be mentioned suitably.

  In this case, it is preferable to adjust the type and amount of the solvent contained in the silver film-forming composition of the present embodiment in accordance with the selected coating method, which is suitable for the coating method. It is preferable to have a viscosity.

[Heating conditions]
In the method for forming a silver film according to the embodiment of the present invention, the heating temperature is a temperature at which silver particles that are components of the composition for forming a silver film of the present embodiment are fused with each other and an organic substance such as a solvent is decomposed and volatilized. There is no particular limitation as long as it is. For example, the heating temperature is preferably 50 ° C. or higher, more preferably in the range of 50 ° C. to 300 ° C., and more preferably in the range of 50 ° C. to 200 ° C. When the heating temperature is less than 50 ° C., the fusion between the silver particles does not proceed completely, and the remaining organic matter may become remarkable. On the other hand, when the heating temperature exceeds 300 ° C., there is a concern that a substrate made of an organic material cannot be used. In other words, when the heating temperature is 200 ° C. or lower, a desired substrate can be selected and used from the above-mentioned diverse group of substrates including a substrate made of an organic material.

  However, when the heating temperature is 200 ° C. or less, the conventional technique using silver fine particles has a concern that the characteristics of the silver film may be deteriorated due to so-called insufficient heating. However, the silver film formation method of this embodiment can perform silver film formation using the composition for silver film formation of this embodiment. As described above, the silver film-forming composition of this embodiment is prepared so as to contain uniform silver particles having a small particle size as a component. Therefore, according to the silver film forming method of the present embodiment, a silver film having desired characteristics, particularly a desired silver film having excellent resistance characteristics can be formed even under heating conditions of 200 ° C. or less. Therefore, also from the viewpoint of simplicity, in the silver film forming method of the embodiment of the present invention, the heating temperature is preferably 200 ° C. or less as described above.

  The heating time may be appropriately selected in consideration of the type of each component such as a solvent and the desired conductivity (resistance value) of the silver film, and is not particularly limited. And when the comparatively low heating temperature of about 200 degreeC or less is selected, it is preferable that heating time shall be about 5 minutes-about 180 minutes.

  As described above, the silver film forming method of the embodiment of the present invention can easily form a low resistance silver film by heating at a low temperature using the silver film forming composition of the present embodiment. . And the wiring board of embodiment of this invention can be provided using the silver film of embodiment of this invention on the obtained board | substrate.

<Electronic equipment>
The silver film formation method of embodiment of this invention mentioned above forms the silver film of embodiment of this invention using the composition for silver film formation of embodiment of this invention. And the silver film of embodiment of this invention can provide the electronic device of embodiment of this invention which uses it as wiring.

  Examples of the electronic apparatus of the present invention include a touch panel, a liquid crystal display element, an organic EL element, and the like. Moreover, an electronic device with a touch panel including a touch panel can be given as an input device.

  Hereinafter, the touch panel of the embodiment of the present invention exemplified as the electronic apparatus of the embodiment of the present invention will be described.

[Touch panel]
The touch panel according to the embodiment of the present invention is, for example, a touch panel having a light-transmissive insulating film formed on a substrate provided with a detection electrode and a lead-out wiring for extracting the detection electrode so as to cover the detection electrode. . This touch panel can be, for example, a capacitive touch panel.
Note that the touch panel according to the embodiment of the present invention may have a structure in which the above-described insulating film is not provided.

  FIG. 1 is a plan view showing a touch panel according to an embodiment of the present invention.

  FIG. 2 is a sectional view taken along line B-B ′ of FIG. 1.

  As shown in FIG. 1, the touch panel 21 of the present embodiment includes a first detection electrode 23 extending in the X direction and a second detection electrode extending in the Y direction orthogonal to the X direction on the surface of the transparent substrate 22. 24.

  The transparent substrate 22 can be a glass substrate. The transparent substrate 22 can also be a resin substrate. In that case, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyethylene film, a polypropylene film, a polyethersulfone film, a polycarbonate film, a polyacryl film, a polyvinyl chloride film, A polyimide film, a ring-opened polymer film of cyclic olefin, a film made of a hydrogenated product thereof, and the like can be used. The thickness of the transparent substrate 22 can be 0.1 mm to 3 mm in the case of a glass substrate. In the case of a resin substrate, it can be 10 μm to 3000 μm.

  A plurality of first detection electrodes 23 and second detection electrodes 24 are arranged. The first detection electrodes 23 and the second detection electrodes 24 are arranged in a matrix in the operation area of the touch panel 21. The first detection electrode 23 is used to detect the coordinate in the Y direction of the touch position by the operator. The second detection electrode 24 is used to detect the coordinate in the X direction of the touch position by the operator. The first detection electrode 23 and the second detection electrode 24 are provided in the same layer on the same surface of the transparent substrate 22. The number of the first detection electrodes 23 and the second detection electrodes 24 is not limited to the example shown in FIG. 1, but is preferably determined according to the size of the operation area and the required touch position detection accuracy. . That is, the touch panel 21 can be configured by using a larger number or a smaller number of the first detection electrodes 23 and the second detection electrodes 24.

  As shown in FIG. 1, each of the first detection electrode 23 and the second detection electrode 24 includes a plurality of rhomboid electrode pads 30. The first detection electrode 23 and the second detection electrode 24 are arranged such that the electrode pad 30 of the first detection electrode 23 is separated from the electrode pad 30 of the second detection electrode 24 adjacent thereto. At this time, the gap between the electrode pads 30 is very small enough to ensure insulation.

  And the 1st sensing electrode 23 and the 2nd sensing electrode 24 are arrange | positioned so that the part which mutually cross | intersects can be made as small as possible. Then, the electrode pads 30 constituting the first detection electrode 23 and the second detection electrode 24 are arranged over the entire operation area of the touch panel 21.

  As shown in FIG. 1, the electrode pad 30 may have a rhombus shape, but is not limited to such a shape, and may be a polygonal shape such as a hexagon, for example.

  Each of the first detection electrode 23 and the second detection electrode 24 is preferably a transparent electrode so as not to lower the visibility of a display such as a liquid crystal display element (not shown) disposed under the touch panel 21. Here, the transparent electrode is an electrode having high transparency to visible light. As the first detection electrode 23 and the second detection electrode 24, an electrode made of a transparent conductive material such as an electrode made of ITO or an electrode made of indium oxide and zinc oxide can be used. When the 1st sensing electrode 23 and the 2nd sensing electrode 24 consist of ITO, respectively, it is preferable that those thickness shall be 10 nm-100 nm so that sufficient electroconductivity can be ensured.

  The formation of the first detection electrode 23 and the second detection electrode 24 can be performed using a known method. For example, the first detection electrode 23 and the second detection electrode 24 can be formed by forming a film made of a transparent conductive material such as ITO by a sputtering method or the like and performing patterning using a photolithography method or the like. it can.

  As shown in FIGS. 1 and 2, the first detection electrode 23 and the second detection electrode 24 are formed on the same surface of the transparent substrate 22 and form the same layer. Therefore, the first detection electrode 23 and the second detection electrode 24 intersect at a plurality of locations in the operation region, and form an intersection 28.

  As shown in FIG. 2, the touch panel 21 of the present embodiment is divided so that one of the first detection electrode 23 and the second detection electrode 24 does not contact the other at the intersection 28. That is, the first detection electrode 23 is connected at the intersection 28, but the second detection electrode 24 extending in the left-right direction in FIG. 2 is divided and formed. A bridge electrode 32 is provided to electrically connect the disconnected portion of the second detection electrode 24. An interlayer insulating film 29 made of an insulating material is provided between the bridge electrode 32 and the first detection electrode 23.

As shown in FIG. 2, the interlayer insulating film 29 provided on the first detection electrode 23 at the intersection 28 is formed of a material having excellent light transmittance. The interlayer insulating film 29 can be formed by applying polysiloxane, acrylic resin, acrylic monomer, or the like by a printing method, performing patterning when necessary, and then heat-curing it. When formed using polysiloxane, the interlayer insulating film 29 is an inorganic insulating layer made of silicon oxide (SiO ₂ ). Further, when an acrylic resin and an acrylic monomer are used, the interlayer insulating film 29 is an organic insulating layer made of resin. In the case where SiO ₂ is used for the interlayer insulating film 29, for example, the SiO ₂ film is formed only on the first detection electrodes 23 at the intersections 28 by a sputtering method using a mask to form the interlayer insulating film 29. You can also

  A bridge electrode 32 is provided on the interlayer insulating film 29. As described above, the bridge electrode 32 functions to electrically connect the second detection electrodes 24 that are interrupted at the intersection 28. The bridge electrode 32 is preferably formed of a material having excellent light transmittance such as ITO. By providing the bridge electrode 32, the second detection electrode 24 can be electrically connected in the Y direction.

  As shown in FIG. 2, the first detection electrode 23 and the second detection electrode 24 have a shape in which a plurality of rhomboid electrode pads 30 are arranged vertically or horizontally as described above. In the first detection electrode 23, the connection portion located at the intersection 28 has a shape narrower than the rhomboid electrode pad 30 of the first detection electrode 23. The bridge electrode 32 is also narrower than the rhomboid electrode pad 30 and is formed in a strip shape.

  Terminals (not shown) are provided at the ends of the first detection electrode 23 and the second detection electrode 24 of the touch panel 21, respectively, and lead-out wirings 31 are drawn from the terminals. The lead-out wiring 31 can be a metal wiring using the silver film of the above-described embodiment of the present invention. Similarly, the terminal can also be formed using the silver film of the embodiment of the present invention.

  That is, the lead-out wiring 31 and the like of the touch panel 21 can be formed according to the silver film forming method of the embodiment of the present invention described above using the silver film forming composition of the embodiment of the present invention described above.

  For example, by the coating method exemplified in the silver film forming method of the embodiment of the present invention, the coating film of the silver film forming composition of the present embodiment is made transparent with the first detection electrode 23, the second detection electrode 24, and the like formed thereon. A wiring pattern is formed on the substrate 22. For example, a coating film is formed by direct drawing using an inkjet printing method, a gravure printing method, a gravure offset printing method, a reverse offset printing method, a flexographic printing method, a (silk) screen printing method, or letterpress printing, and wiring. A pattern can be formed.

  And the wiring pattern which is a coating film of the composition for silver film formation of this embodiment is heated, and can comprise the lead-out wiring 31 grade | etc.,.

  The lead-out wiring 31 uses an external connection circuit (not shown) that detects the position of voltage application and touch operation to the first detection electrode 23 and the second detection electrode 24 using a connection terminal (not shown) at the end thereof. Is electrically connected.

  As shown in FIGS. 1 and 2, light is applied to the surface of the transparent substrate 22 on which the first detection electrode 23 and the second detection electrode 24 are disposed so as to cover the first detection electrode 23 and the second detection electrode 24. A transparent insulating film 25 is disposed.

  The insulating film 25 is formed by patterning so as to cover and protect the first detection electrode 23 and the second detection electrode 24 in the operation region of the touch panel 21. In addition, the insulating film 25 is formed by patterning so that the connection terminals (not shown) at the ends of the lead-out wirings 31 drawn from the first detection electrode 23 and the second detection electrode 24 are exposed.

  For example, a known radiation-sensitive resin composition can be used to form the insulating film 25, and the insulating film 25 can be disposed on the first detection electrode 23 and the second detection electrode 24 by performing a predetermined patterning. it can.

  The touch panel 21 is a cover film made of a transparent resin using, for example, an adhesive layer (not shown) made of an acrylic transparent adhesive on the formation surface of the first detection electrode 23 and the second detection electrode 24 of the transparent substrate 22. (Not shown) can be provided.

  The touch panel 21 having the above configuration measures the capacitance when the first detection electrodes 23 and the second detection electrodes 24 are arranged in a matrix in the operation area, and when there is a touch operation such as an operator's finger. The contact position of a finger or the like can be detected from the change in capacitance that occurs. And the touch panel 21 is mounted on displays, such as a liquid crystal display element and an organic EL element, and can be used suitably as an input device of the display of an electronic device.

  Therefore, the composition for forming a silver film of the embodiment of the present invention can form the silver film of the embodiment of the present invention on a substrate. As described above, the silver film of the embodiment of the present invention can constitute a lead wiring on the substrate. And the silver film of embodiment of this invention can be used for a lead-out wiring, and can comprise the touchscreen which is an example of a wiring board. The silver film of the embodiment of the present invention can provide the electronic device of the embodiment of the present invention such as a liquid crystal display element or an organic EL element provided with the touch panel.

  Hereinafter, embodiments of the present invention will be described more specifically based on examples. However, the present invention is not limited to these examples.

Details of the amine compounds used in Examples and Comparative Examples are shown below.
BA: n-butylamine HA: n-hexylamine OA: n-octylamine DA: n-dodecylamine EHA: 2-ethylhexylamine EUPA: 3-ethoxypropylamine DEA: diethylamine TEA: triethylamine EHOPA: 3- (2-ethylhexyl) Oxy) propylamine

[Example 1]
13.8 g (0.188 mol) of n-butylamine (BA) as an amine compound is placed in a flask of the reaction vessel, cooled in an ice bath, and 5.4 g (0.118 mol) of formic acid is added dropwise while stirring. -Salts of butylamine (BA) and formic acid were prepared.

  Next, 21.8 g (0.094 mol) of silver (I) oxide, 9.51 g (0.094 mol) of n-hexylamine (HA) and 6.06 g of n-octylamine (OA) were added to another flask. 047 mol) and 8.71 g (0.047 mol) of n-dodecylamine (DA) were mixed and stirred to prepare a silver oxide dispersion.

  Next, the above-mentioned n-butylamine (BA) and formic acid salt were added dropwise to the silver oxide dispersion in the flask while stirring. After dropping, the flask was heated to 30 ° C. and stirred for 30 minutes to obtain a black liquid.

  Next, after adding 100 g of methanol to the obtained black liquid, stirring was stopped and the mixture was allowed to stand for 1 hour. Thereafter, the supernatant was separated by decantation to obtain 18.0 g of a precipitate containing silver particles.

  Then, when the average particle diameter of the obtained silver particles was measured using a transmission electron microscope (TEM) (H-7650, manufactured by Hitachi, Ltd.), it was 55 nm. When 100 primary particle sizes observed in the TEM image were randomly measured, the standard deviation was within 20 nm, and it was confirmed that monodispersed silver particles having a uniform particle size were produced.

  Next, 1.5 g of terpineol was added to 8.5 g of the precipitate containing the above silver particles to prepare a paste-like composition for forming a silver film. The prepared composition for forming a silver film was applied to a glass substrate, the glass substrate was placed on a hot plate, and heated at 120 ° C. for 1 hour. It was 12 micrometers when the film thickness was measured with respect to the silver film formed by heating using the contact-type film thickness meter (Theoncor Instruments company make, P10). Moreover, when the volume resistance value was measured by the four probe method with respect to the formed silver film, the volume resistance value was 45 microhm * cm.

The above production conditions and evaluation results are summarized in the column of Example 1 in the following table. That is, in the column of the salt formation reaction in the following table, the molar ratio of formic acid and amine compound (indicated in Table 1 as amine) used for the salt formation reaction and the type of amine compound are shown. In addition, the column of silver oxide dispersion preparation in the following table shows the molar ratio of silver (I) oxide and amine compound (denoted as amine in the table) used for that purpose and the type of amine compound. It was. At this time, the molar ratio of silver (I) used for the preparation of the silver oxide dispersion was set to 1 as a reference, and the molar ratios of other components were shown in the corresponding columns as numerical values in parentheses. Moreover, the average particle diameter (nm) measured by the above-mentioned TEM is shown in the column of average particle diameter in the following table, and the volume resistance value (μΩ · cm by the above-mentioned four-terminal method is shown in the column of volume resistance value. ) Measurement results are shown.
For Example 2 to Example 27, which will be described later, as in Example 1, the compounding ratio of each component and the evaluation results of the obtained silver particles and silver film are shown in the table below.

[Examples 2 to 27]
The molar ratio of formic acid and amine compound and the type of amine compound used for the salt formation reaction, and the molar ratio of silver oxide (I) and amine compound and the type of amine compound used for the preparation of the silver oxide dispersion Except as shown in Table 1, production of silver particles, preparation of a composition for forming a silver film, formation of a silver film, and measurement of volume resistance were carried out in the same manner as in Example 1. The results are summarized in the corresponding column of the following table. The standard deviation when randomly measuring 100 primary particle diameters of silver particles observed in the TEM image is within 20 nm in all examples, and the silver particles having a uniform particle diameter are monodispersed. Generation was confirmed.

[Comparative example]
25.0 g of methanol and 20.0 g of silver (I) oxide were placed in a reaction vessel flask, 10.0 g of formic acid was added with stirring, and the mixture was reacted for 4 hours to obtain a silver formate dispersion. To the obtained silver formate dispersion, 46.0 g of 3- (2-ethylhexyloxy) propylamine (EHOPA) was added with stirring and reacted for 2 hours to obtain a gray dispersion. After cooling to room temperature, 100 g of methanol was added, stirring was stopped, and the mixture was allowed to stand for 1 hour. Thereafter, the supernatant was separated by decantation to obtain 17.5 g of an off-white precipitate.

  Next, the obtained grayish white precipitate was observed using a transmission electron microscope (TEM) (H-7650, manufactured by Hitachi, Ltd.), and silver particles having a particle size of about several nanometers to several tens of nanometers were produced. Could not be confirmed.

  Next, 1.5 g of terpineol was added to 8.5 g of the obtained grayish white precipitate to prepare a paste-like composition. The prepared composition was apply | coated to the glass substrate, the glass substrate was installed on the hotplate, and it heated at 100 degreeC for 1 hour. It was 22 micrometers when the film thickness was measured with respect to the film | membrane formed by heating using the contact-type film thickness meter (Theoncor Instruments company make, P10). Moreover, when the volume resistance value measurement by the four probe method was performed with respect to the formed film | membrane, compared with the silver film of the above-mentioned Example 1- Example 27, resistance value was remarkably high, and it was out of the measurement range. .

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The silver particles of the present invention are suitable for forming a silver film forming composition used for forming a silver film, and the silver film forming composition of the present invention containing the silver particles is used for a circuit board in the electronics field. It can be suitably used as a composition for forming a conductive pattern. And the silver film of this invention can be used for manufacture of an electronic component etc. in the electronics field | area etc. For example, the silver film of the present invention can be used for the production of wirings, circuit boards, antennas, sensors, arithmetic elements and display elements. Furthermore, the composition for forming a silver film of the present invention can be suitably used as a conductive ink for various types of printing such as ink jet printing, screen printing, flexographic printing, gravure offset printing, and reverse offset printing.

21 Touch Panel 22 Transparent Substrate 23 First Sense Electrode 24 Second Sense Electrode 25 Insulating Film 28 Intersection 29 Interlayer Insulating Film 30 Electrode Pad 31 Lead-out Wire 32 Bridge Electrode

Claims (1)

  A method for producing silver particles, comprising mixing a monocarboxylic acid amine salt and silver oxide to produce silver particles used in a composition for forming a silver film.