JP5852360B2 - Silver ink composition - Google Patents

Description

  The present invention relates to a silver ink composition.

  Metallic silver is widely used as a recording material and printing plate material, and as a highly conductive material because of its excellent conductivity. As a general method for producing metallic silver, a method of heating silver oxide, which is an inorganic compound, in the presence of a reducing agent can be exemplified. Specifically, for example, particulate silver oxide is dispersed in a binder, a reducing agent is added thereto to prepare a paste, and the paste is applied to a substrate or the like and heated. Thus, by heating in the presence of a reducing agent, the silver oxide is reduced, the metallic silver produced by the reduction is fused together, and a film containing metallic silver is formed.

  However, when silver oxide is used as a material for forming metallic silver, a reducing agent is required, and the heating temperature is about 300 ° C., which is extremely high. Further, when metallic silver is used as the conductive material, it is necessary to use finer silver oxide particles in order to reduce the resistance of the formed film.

On the other hand, in recent years, a method for forming metallic silver using organic acid silver instead of the above-described inorganic substance has also been reported. As such organic acid silver, for example, silver behenate, silver stearate, and silver α-ketocarboxylate have been reported (see Patent Documents 1 to 3).
However, when silver behenate is used, there is a problem that heating in the presence of a reducing agent is necessary to form metallic silver. Further, when silver stearate or silver α-ketocarboxylate is used, the heating temperature needs to be about 210 ° C. or higher in order to form metallic silver quickly, although it is lower than when inorganic material is used. There was a problem that there was.

  In recent years, a method for heating silver β-ketocarboxylate has been disclosed as a method for producing metallic silver that solves these problems (see Patent Document 4). This method is an extremely excellent method in that a reducing agent is not required and metal silver having excellent characteristics can be formed at a heating temperature lower than that of the conventional method. And the specific method of forming metallic silver on a base material using the silver ink composition mix | blended with such silver (beta) -ketocarboxylate is disclosed (refer patent document 5).

JP 2003-191646 A Japanese Patent Laid-Open No. 10-183207 JP 2004-315374 A International Publication No. 2007/004437 Pamphlet JP 2009-114232 A

Patent Document 5 describes that a reducing agent is certainly unnecessary and that metallic silver can be formed at a lower heating temperature than conventional ones. For example, silver ink containing silver 2-methylacetoacetate is blended. A specific example is described in which a metallic silver film is formed by heating the composition at 150 ° C. for 5 minutes.
However, although it is lower than conventional, at a heating temperature of 150 ° C., a substrate having low heat resistance cannot be used as a base material for forming metallic silver, and the use of the silver ink composition is limited. was there. For example, certain types of resinous films and papers are thin and light and have great potential as a base material for information recording media. However, because of their low heat resistance, a high heating temperature is required for pattern formation. The ink composition can not be used. And development of the method of forming metallic silver on such a low heat resistant base material is strongly desired.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the silver ink composition which can form metallic silver at the heating temperature lower than before.

To solve the above problem,
The present invention comprises a combination of one or more silver β -ketocarboxylates selected from the group consisting of silver 2-methylacetoacetate, silver acetoacetate, silver isobutyrylacetate and silver pivaloylacetate , n-hexylamine and ethylene glycol. The amount of the n-hexylamine is 2.5 mol or more per 1 mol of the β-ketocarboxylate, and the amount of the β-ketocarboxylate is 1 mol. The silver ink composition is characterized in that the blending amount of ethylene glycol is 3.3 mol or more.

  According to the present invention, metallic silver can be formed at a lower heating temperature than before. Therefore, metallic silver can be formed also on a substrate having low heat resistance such as certain resinous films and papers.

It is a figure which shows the FT-IR spectrum of the silver acetoacetate obtained by manufacture example 1. It is a figure which shows the FT-IR spectrum of the silver isobutyryl acetate obtained by manufacture example 2, and the silver pivaloyl acetate obtained by manufacture example 3.

<Silver ink composition>
The silver ink composition of the present invention comprises silver β-ketocarboxylate (hereinafter sometimes abbreviated as β-ketocarboxylate (1)) represented by the following general formula (1), n-hexylamine, A chain dihydric alcohol having a hydroxyl group at both ends of the molecular chain having 2 to 5 carbon atoms and the largest number of carbon atoms (hereinafter sometimes abbreviated as dihydric alcohol (2)), The amount of n-hexylamine is 2.5 mol or more per 1 mol of β-ketocarboxylate (1), and the amount of β-ketocarboxylate (1) is 1 mol. The blending amount of the dihydric alcohol (2) is 3.3 mol or more. As the dihydric alcohol (2), ethylene glycol (1,2-ethanediol) is preferred.

(In the formula, R is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 20 carbon atoms, represented by the general formulas “R ¹ -CY ₂ —”, “CY ₃ —”, “R ¹ —CHY— ”,“ R ² O— ”,“ (R ³ O) ₂ CY— ”or“ R ⁵ R ⁴ N— ”, a phenyl group optionally having a substituent, a hydroxyl group Or an amino group, wherein the aliphatic hydrocarbon group may have one or more hydrogen atoms substituted with a fluorine atom, a chlorine atom or a bromine atom;
R ¹ is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group; R ² is a linear or branched chain having 1 to 20 carbon atoms Or a cyclic aliphatic hydrocarbon group; R ³ is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 16 carbon atoms, and the plurality of R ³ are the same as or different from each other. R ⁴ and R ⁵ are each independently a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 18 carbon atoms; Y is independently a hydrogen atom; A fluorine atom, a chlorine atom or a bromine atom, and a plurality of Y's may be the same or different from each other; the aliphatic hydrocarbon group in R ^{1 to} R ⁵ is one or more hydrogen atoms are fluorine atoms, chlorine atoms Or may be substituted with a bromine atom;
X is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 20 carbon atoms, represented by the general formulas “R ⁶ O—”, “R ⁶ S—”, “R ⁶ —C (═O ) — ”Or“ R ⁶ —C (═O) —O— ”, a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an optionally substituted phenyl group, or A benzyl group, a cyano group, an N-phthaloyl-3-aminopropyl group or a 2-ethoxyvinyl group, wherein the aliphatic hydrocarbon group has one or more hydrogen atoms substituted by a fluorine atom, a chlorine atom or a bromine atom. A plurality of X may be the same or different from each other;
R ⁶ is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thiophene group, or an optionally substituted phenyl group or diphenyl group. )

(Silver β-ketocarboxylate (1))
First, the silver β-ketocarboxylate (1) will be described.
In the formula, R represents a linear, branched, or cyclic aliphatic hydrocarbon group having 1 to 20 carbon atoms, a general formula “R ¹ -CY ₂ —”, “CY ₃ —”, “R ¹ —”. A group represented by “CHY—”, “R ² O—”, “(R ³ O) ₂ CY—” or “R ⁵ R ⁴ N—”, a phenyl group optionally having a substituent, a hydroxyl group, or It is an amino group.
The aliphatic hydrocarbon group in R may be either a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, and a cycloalkenyl group. A group represented by the general formula “—C _n H _{2n + 1} ”, “—C _n H _2n-1 ” or “—C _n H _2n-3 ” (where each n is independently an integer of 1 to 20) It can be illustrated.

The aliphatic hydrocarbon group in R is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, and examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, Isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, 1-methylbutyl group, n-hexyl group, 2-methyl Pentyl group, 3-methylpentyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,3-dimethylpentyl group, 3-ethylpentyl group, 2,2,3-trimethylbutyl Le group, n- octyl group, an isooctyl group, a nonyl group, a decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group can be exemplified.
Especially, it is more preferable that the said aliphatic hydrocarbon group is a C1-C10 alkyl group, and it is further more preferable that it is a C1-C5 alkyl group.

When the aliphatic hydrocarbon group in R is an alkenyl group, as the alkenyl group, in the alkyl group, one single bond (C—C) between carbon atoms is replaced with a double bond (C═C). Specific examples of preferable ones include vinyl group (ethenyl group), allyl group (2-propenyl group), 1-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group and the like. Can be illustrated.
When the aliphatic hydrocarbon group in R is an alkynyl group, as the alkynyl group, in the alkyl group, one single bond (C—C) between carbon atoms is substituted with a triple bond (C≡C). Specific examples include ethynyl group, propargyl group (2-propynyl group) and the like.
When the aliphatic hydrocarbon group in R is a cycloalkyl group, preferred examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group.
When the aliphatic hydrocarbon group in R is a cycloalkenyl group, preferred examples of the cycloalkenyl group include 1,3-cyclohexadienyl group, 1,4-cyclohexadienyl group, cyclopentadienyl group, and the like. Can be illustrated.

  In the aliphatic hydrocarbon group for R, one or more hydrogen atoms may be substituted with a fluorine atom, a chlorine atom or a bromine atom. The position at which the hydrogen atom is substituted is not particularly limited.

General formulas “R ¹ -CY ₂ —”, “CY ₃ —”, “R ¹ —CHY—”, “R ² O—”, “(R ³ O) ₂ CY—” or “R ⁵ R ⁴ ” in R In the group represented by “N—”, R ¹ is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group.
The aliphatic hydrocarbon group in R ¹ may be either a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, and a cycloalkenyl group. , A group represented by the general formula “—C _n H _{2n + 1} ”, “—C _n H _2n-1 ” or “—C _n H _2n-3 ” (where each n is independently an integer of 1 to 19). Can be illustrated.
Preferred examples of the aliphatic hydrocarbon group for R ¹ include those having 1 to 19 carbon atoms among the aliphatic hydrocarbon groups for R 1.
In the aliphatic hydrocarbon group for R ¹ , one or more hydrogen atoms may be substituted with a fluorine atom, a chlorine atom or a bromine atom, and the position where the hydrogen atom is substituted is not particularly limited.

R ² is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 20 carbon atoms.
The aliphatic hydrocarbon group in R ² may be either a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, and a cycloalkenyl group. , A group represented by the general formula “—C _n H _{2n + 1} ”, “—C _n H _2n-1 ” or “—C _n H _2n-3 ” (n is each independently an integer of 1 to 20). Can be illustrated.
Preferable examples of the aliphatic hydrocarbon group for R ² include those similar to the aliphatic hydrocarbon group for R ² .
In the aliphatic hydrocarbon group for R ² , one or more hydrogen atoms may be substituted with a fluorine atom, a chlorine atom, or a bromine atom, and the position at which the hydrogen atom is substituted is not particularly limited.

R ³ is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 16 carbon atoms, which may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, The same as R ² except that the number is 1-16.
A plurality (two) of R ³ may be the same or different from each other, and the combination of R ^{3 in} the case of being different is not particularly limited.

R ⁴ and R ⁵ are each independently a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 18 carbon atoms, a saturated aliphatic hydrocarbon group and an unsaturated aliphatic hydrocarbon group. Any of group may be sufficient and it is the same as that of R < ² > except that it is C1-C18.

Y is independently a hydrogen atom, a fluorine atom, a chlorine atom, or a bromine atom, and a plurality of Y may be the same as or different from each other. That is, two Ys in the group represented by the general formula “R ¹ —CY ₂ —” and three Ys in the group represented by the general formula “CY ₃ —” are the same or different from each other in each general formula. May be. Y in the group represented by the general formula “R ¹ —CY ₂ —” and Y in the group represented by the general formula “CY ₃ —” may be the same as or different from each other.

The phenyl group in R may have a substituent. That is, in the phenyl group in R, one or more carbon atoms may be substituted with a substituent, and one or more hydrogen atoms may be substituted with a substituent. For example, as a preferable substituent for which a hydrogen atom is substituted, a general formula “R ⁷ —” or “R ⁷ O—” (wherein R ⁷ is each independently a straight chain having 1 to 16 carbon atoms). Group, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group (—OH), a cyano group (—C≡N) or a phenoxy group. _(C 6 _H 5 -O-) and the like. R ⁷ is the same as R ³ . In addition, the position of the substituent in which the hydrogen atom is substituted is not particularly limited, and may be any of the ortho position, the meta position, and the para position.

  R is preferably an alkyl group or a phenyl group.

In the formula, X represents a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 20 carbon atoms, a general formula “R ⁶ O—”, “R ⁶ S—”, “R ⁶ —”. C (= O) - "or" ^R 6 -C (= O) -O- ", a group represented by a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, which may have a substituent Good phenyl group or benzyl group, cyano group, N-phthaloyl-3-aminopropyl group or 2-ethoxyvinyl group.
Plural (two) Xs may be the same as or different from each other, and the combination of Xs when they are different is not particularly limited.

The aliphatic hydrocarbon group for X may be either a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and is the same as the aliphatic hydrocarbon group for R.
Among these, the aliphatic hydrocarbon group in X is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 to 3 carbon atoms. It is more preferable that it is a methyl group or an ethyl group.
In the aliphatic hydrocarbon group for X, one or more hydrogen atoms may be substituted with a fluorine atom, a chlorine atom or a bromine atom, and the position where the hydrogen atom is substituted is not particularly limited.

For the group represented by the general formula “R ⁶ O—”, “R ⁶ S—”, “R ⁶ —C (═O) —” or “R ⁶ —C (═O) —O—” in X, R ⁶ is a linear, branched or cyclic aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thiophene group, or an optionally substituted phenyl group or diphenyl group.
The aliphatic hydrocarbon group for R ⁶ may be either a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and the aliphatic hydrocarbon group for R except for having 1 to 10 carbon atoms. It is the same.

The phenyl group or diphenyl group in R ⁶ may have a substituent. That is, in the phenyl group or diphenyl group in R ⁶ , one or more carbon atoms may be substituted with a substituent, and one or more hydrogen atoms may be substituted with a substituent. For example, preferable examples of the substituent in which a hydrogen atom is substituted include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Moreover, the position of the substituent with which the hydrogen atom is substituted is not particularly limited, and may be any of the ortho position, the meta position, and the para position.

The phenyl group or benzyl group in X may have a substituent. That is, in the phenyl group or benzyl group in X, one or more carbon atoms may be substituted with a substituent, and one or more hydrogen atoms may be substituted with a substituent. For example, preferable examples of the substituent in which a hydrogen atom is substituted include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom; a nitro group (—NO ₂ ) and the like. Moreover, the position of the substituent in which the hydrogen atom is substituted is not particularly limited. For example, in the aromatic ring, any of the ortho position, the meta position, and the para position may be used.

A group represented by the formula “═CH—C ₆ H ₄ —NO ₂ ” may be bonded to only one X of the two Xs.

  X is preferably a hydrogen atom or an alkyl group, and at least one is preferably a hydrogen atom.

  In the present invention, particularly preferable β-ketocarboxylate (1) is silver isobutyryl acetate, silver benzoyl acetate, silver propionyl acetate, silver pivaloyl acetate, silver acetoacetate, silver α-methylacetoacetate (silver 2-methylacetoacetate), An example is α-ethyl acetoacetate silver (2-ethyl acetoacetate silver).

  β-ketocarboxylate (1) may be used alone or in combination of two or more. When using 2 or more types together, the combination and ratio may be appropriately adjusted according to the purpose.

  In the β-ketocarboxylate silver (1), for example, the group represented by the formula “—OAg” bonded to the carbonyl group of the β-ketocarboxylate silver (1) is substituted with an alkoxy group or an aralkyloxy group. It can be produced by using a β-ketocarboxylic acid ester as a raw material, hydrolyzing the ester bond under basic conditions to obtain a β-ketocarboxylate, and then reacting with a silver compound such as silver nitrate.

The compounding quantity of (beta) -ketocarboxylate (1) in the silver ink composition of this invention is not specifically limited. However, β-ketocarboxylic acid occupies the total amount of the blended components because a practical amount of metallic silver can be easily formed by increasing the concentration of silver β-ketocarboxylate (1) in the silver ink composition. The ratio of silver (1) is preferably 2.5% by mass or more, and more preferably 11% by mass or more from the viewpoint of obtaining higher strength metallic silver.
The upper limit of the ratio of the silver β-ketocarboxylate (1) in the total amount of the blending components may be within a range that does not impair the handleability of the silver ink composition.

(N-hexylamine)
The compounding amount of n-hexylamine in the silver ink composition of the present invention is 2.5 mol or more and preferably 3 mol or more per mol of the β-ketocarboxylate (1). By setting it to the lower limit value or more, a remarkable effect that the formation temperature of metallic silver can be lowered is obtained.
The upper limit of the amount of n-hexylamine is not particularly limited. However, since the practical amount of metallic silver can be easily formed by increasing the concentration of silver β-ketocarboxylate (1) in the silver ink composition, the compounding amount of n-hexylamine is β -It is preferable that it is 45 mol or less per 1 mol of compounding quantities of silver ketocarboxylate (1), and it is more preferable that it is 10 mol or less from the point from which higher intensity | strength metallic silver is obtained.

(Dihydric alcohol (2))
The dihydric alcohol (2) is a chain dihydric alcohol having hydroxyl groups at both ends of the molecular chain having 2 to 5 carbon atoms and the largest number of carbon atoms. That is, a structure in which one hydrogen atom is substituted with a hydroxyl group at each of the carbon atoms at both ends of a continuous hydrocarbon chain having the largest number of carbon atoms in a chain hydrocarbon having 2 to 5 carbon atoms It is what has.
The dihydric alcohol (2) may be either linear or branched, but is preferably linear.
Specific examples of the dihydric alcohol (2) include ethylene glycol (1,2-ethanediol, HO—CH ₂ CH ₂ —OH), 1,3-propanediol (HO—CH ₂ CH ₂ CH ₂ —OH). ), 1,4-butane diol _{(HO-CH 2 CH 2 CH} 2 CH 2 -OH), 1,5- pentanediol _{(HO-CH 2 CH 2 CH} 2 CH 2 CH 2 -OH), 2- methyl - 1,3-propanediol _{(HO-CH 2 CH (CH} 3) CH 2 -OH), 2- methyl-1,4-butanediol _{(HO-CH 2 CH (CH} 3) CH 2 CH 2 -OH) is As an example, ethylene glycol is particularly preferred.

  A dihydric alcohol (2) may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types together, the combination and ratio may be appropriately adjusted according to the purpose.

The compounding amount of the dihydric alcohol (2) in the silver ink composition of the present invention is 3.3 mol or more and 3.5 mol or more per mol of the β-ketocarboxylate (1). Is preferred. By setting it to the lower limit value or more, a remarkable effect that the formation temperature of metallic silver can be lowered is obtained.
The upper limit of the compounding amount of the dihydric alcohol (2) is not particularly limited. However, the blending amount of the dihydric alcohol (2) is such that a practical amount of metallic silver can be easily formed by increasing the concentration of the silver β-ketocarboxylate (1) in the silver ink composition. The β-ketocarboxylate (1) is preferably added in an amount of 50 mol or less per mol of the compound (1), and more preferably 12 mol or less from the viewpoint of obtaining higher-strength metallic silver.

(Other ingredients)
The silver ink composition of the present invention may further contain other components in addition to β-ketocarboxylate silver (1), n-hexylamine and dihydric alcohol (2) as necessary.
The other components are not particularly limited as long as they do not hinder the effects of the present invention, and can be arbitrarily selected according to the purpose. Preferred examples include various solvents, binder resins, and acetylene alcohols.

The said solvent should just be a thing which does not react with each compounding component, As preferable thing, alcohol, ketones, esters, and ethers which do not correspond to dihydric alcohol (2) can be illustrated.
As the binder resin, those commonly used in this field can be used.

The acetylene alcohols are compounds having both an ethynyl group (—C≡CH) and a hydroxyl group (—OH). For example, the acetylene alcohol has a hydroxyl group, but is distinguished from the solvent.
The acetylene alcohols are preferably those represented by the following general formula (II).

(In the formula, R ′ and R ″ are each independently an alkyl group having 1 to 20 carbon atoms, a phenyl group, or an optionally substituted phenyl group.)

In the formula, R ′ and R ″ each independently represent an alkyl group having 1 to 20 carbon atoms, a phenyl group, or a phenyl group which may have a substituent.
The alkyl group may be linear, branched or cyclic.
Examples of the substituent that the phenyl group may have include a saturated or unsaturated monovalent aliphatic hydrocarbon group having 1 to 16 carbon atoms, and a monovalent group in which the aliphatic hydrocarbon group is bonded to an oxygen atom. Group, fluorine atom, chlorine atom, bromine atom, hydroxyl group, cyano group, phenoxy group and the like.
The aliphatic hydrocarbon group as a substituent may be linear, branched or cyclic, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group and a cycloalkenyl group. When the aliphatic hydrocarbon group is cyclic, it may be monocyclic or polycyclic.
Preferred examples of the monovalent group in which the aliphatic hydrocarbon group is bonded to an oxygen atom include an alkoxy group, an alkenyloxy group, an alkynyloxy group, a cycloalkoxy group, and a cycloalkenyloxy group.
When the phenyl group has a substituent, the number and position of the substituent are not particularly limited.
R ′ and R ″ are preferably an alkyl group having 1 to 20 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 10 carbon atoms.

  When the other components are liquid, the boiling point thereof is preferably lower than the heating temperature of the silver ink composition described later.

  One of these other components may be used alone, or two or more thereof may be used in combination. When using 2 or more types together, the combination and ratio may be appropriately selected according to the purpose.

  In the silver ink composition of the present invention, the ratio of the total amount of silver β-ketocarboxylate (1), n-hexylamine and dihydric alcohol (2) in the total amount of the blending components is preferably 80% by mass or more. More preferably, it is 90 mass% or more, and may be 100 mass%. Usually, the higher this ratio, the more remarkable the effect that the formation temperature of metallic silver can be lowered.

  The silver ink composition of the present invention greatly increases the formation temperature of metallic silver by selecting n-hexylamine and dihydric alcohol (2) as essential components used together with silver β-ketocarboxylate (1). Can be reduced. For example, in Japanese Patent Application Laid-Open No. 2009-114232, a silver ink composition containing silver 2-methylacetoacetate was used, and this was heated at 150 ° C. for 5 minutes to form a metallic silver film. Specific examples are described. On the other hand, by using the silver ink composition of the present invention, even at a temperature of about 100 ° C., which is significantly lower than 150 ° C., metallic silver having extremely excellent characteristics with high purity, low resistance, and high composition uniformity can be obtained. Can be formed. And since the formed metal silver has high intensity | strength, the silver ink composition of this invention is suitable also for fine and complicated pattern formation, such as wiring, for example.

  Among the many alcohols, the dihydric alcohol (2) is (a) a chain dihydric alcohol, (b) has 2 to 5 carbon atoms, and (c) both molecular chains with the largest number of carbon atoms. It has a very limited structure of having a hydroxyl group at the end. Moreover, n-hexylamine is only one kind of organic base discovered from many basic compounds. Thus, the combination of n-hexylamine and dihydric alcohol (2) cannot be easily selected from the enormous combinations of basic compounds and alcohols, and such extremely limited components For the first time, it becomes possible to form metallic silver from the β-ketocarboxylate silver (1) at a significantly low heating temperature.

<Method for producing silver ink composition>
The silver ink composition of the present invention can be produced by blending silver β-ketocarboxylate (1), n-hexylamine and dihydric alcohol (2), and other components as necessary.
At the time of blending each component, these components may be added and then mixed, or some components may be mixed while being sequentially added, or all components may be mixed while being sequentially added. good.
The mixing method is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or a stirring blade, a method of mixing using a mixer, a method of mixing by applying ultrasonic waves, and the like. good.

  The compounding components may be completely dissolved in the silver ink composition, or a part of the components may be dispersed without being dissolved.

  The temperature at the time of blending is not particularly limited as long as each blending component does not deteriorate, but is preferably −5 to 30 ° C.

<Method for producing metallic silver>
Metal silver can be formed by heating the silver ink composition of the present invention.
The metallic silver is preferably formed on a substrate, and in this case, the silver ink composition of the present invention may be attached on the substrate and heated at a desired temperature.

  The method for attaching the silver ink composition on the substrate is not particularly limited. For example, a method of applying a silver ink composition on a substrate using a coating apparatus; a method of placing a silver ink composition on a substrate using a discharge means such as a syringe or a syringe can be exemplified.

  The coating method of the silver ink composition is not particularly limited, and is screen printing; offset printing; dip method; ink jet method; dispenser method; air knife coater, curtain coater, die coater, blade coater, roll coater, gate roll coater, bar. Examples thereof include a method using various coaters such as a coater, rod coater, gravure coater, and spin coater; and a method using an apparatus such as a wire bar. For example, when the application method is selected according to the viscosity of the silver ink composition, the silver ink composition can be applied more stably.

  The adhesion amount of the silver ink composition is not particularly limited. For example, the adhesion amount of silver β-ketocarboxylate (1) in the silver ink composition, the thickness of the target metallic silver, and the like can be adjusted as appropriate. It ’s fine.

The heating of the silver ink composition is preferably started after the silver ink composition is deposited and before the composition or properties thereof are changed. Here, “change in composition” means that, for example, a part of the components in the silver ink composition disappears due to volatilization or the like, or a new component is added to the silver ink composition due to moisture absorption or the like. It means that the type or ratio of the component to be changed clearly changes. In addition, the “change in properties” means that the appearance of the silver ink composition is clearly changed by, for example, precipitating a part of the dissolved components or separating them without precipitating. .
The time from the adhesion of the silver ink composition to the start of heating may be adjusted according to the combination of the ingredients of the silver ink composition.

The heating temperature of the silver ink composition may be appropriately adjusted according to the decomposition temperature of the silver β-ketocarboxylate (1), but metallic silver can be formed at an unprecedented extremely low heating temperature of about 100 ° C. It is. This is because the decomposition of the silver β-ketocarboxylate (1) is remarkably accelerated by using n-hexylamine and the dihydric alcohol (2) in combination as described above. Here, the “decomposition temperature of β-ketocarboxylate (1)” refers to the decomposition temperature when silver β-ketocarboxylate (1) is present alone.
Accordingly, when the heating temperature of the silver ink composition is preferably 115 ° C. or lower, more preferably 105 ° C. or lower, for example, metallic silver can be formed on a substrate having low heat resistance. The ink composition is extremely excellent in usefulness and versatility. The lower limit of the heating temperature of the silver ink composition is not particularly limited as long as metallic silver can be formed, but it is usually preferably 90 ° C.

  The method for heating the silver ink composition is not particularly limited, and examples include heating with an electric furnace and heating with a thermal head, and the heating may be performed in the air or in an inert gas atmosphere. And you may carry out under any of normal pressure and pressure reduction.

  The heating time may be appropriately set according to the heating temperature and the heating method, and is not particularly limited. For example, when heating at about 100 ° C. using an electric furnace, metallic silver having excellent characteristics can be formed even with a heating time of about 5 to 30 minutes.

The material of the substrate may be appropriately selected according to the purpose, and is not particularly limited. Specific examples include inorganic materials such as ceramic and quartz glass; organic materials such as various resins; and papers.
The resin is preferably a synthetic resin, such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, acrylic resin, AS resin, ABS resin, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene. Examples thereof include naphthalate, polybutylene naphthalate, polyphenylene sulfide, polysulfone, polycarbonate, epoxy resin, melamine resin, phenol resin, urea resin, polyurethane and polyimide.
Examples of the paper include base paper, art paper, coated paper, cast coated paper, resin coated paper, glassine paper, glossy paper, and synthetic paper.
In the silver ink composition of the present invention, the β-ketocarboxylate (1) is sufficiently decomposed at an extremely low heating temperature of about 100 ° C., and therefore a group having low heat resistance that cannot be used in a conventional method requiring high temperature treatment. Materials can also be used. Therefore, for example, a substrate made of a material such as paper is particularly suitable.

  The substrate may have a single layer structure or a multi-layer structure. In the case of a multi-layer structure, the materials of the plurality of base materials may all be the same, some may be different, or all may be different. When a plurality of base materials having different materials are used, the combination and ratio of the materials may be appropriately selected according to the purpose.

  The thickness of the base material can be arbitrarily set according to the material and purpose and is not particularly limited, but it is usually preferably 10 to 15000 μm.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples. In the following, the unit “K” represents kilo (10 ³ ), and “M” represents mega (10 ⁶ ).

<Manufacture of silver ink composition>
[Example 1]
As shown in Table 1, 2-methyl acetoacetate silver (α-methyl acetoacetate) (1.25 g, 5.61 mmol), n-hexylamine (1.70 g, 16.83 mmol), and ethylene glycol (2.05 g , 33.10 mmol) was mixed while cooling with ice water to prepare a silver ink composition.

[Examples 2 to 14, Reference Examples 1 to 3]
A silver ink composition was produced in the same manner as in Example 1 except that the type and amount of dihydric alcohol (2) and the amount of n-hexylamine used were as shown in Table 1.

[Comparative Examples 1 to 16]
As shown in Table 2, a silver ink composition was produced in the same manner as in Example 1 except that the types and amounts of base and alcohol were set.

<Manufacture of metallic silver>
Using a dropper, the silver ink compositions of Examples 1 to 14, Reference Examples 1 to 3, and Comparative Examples 1 to 16 were dropped one by one on different locations on the substrates shown in Tables 3 and 4, By dropping 5 drops in total, 5 spots of the silver ink composition were produced. The drop volume of one drop was 10 to 20 μl. The used base material is specifically as follows.
PET (polyethylene terephthalate): Tetron SL-50 (trade name, manufactured by Teijin Ltd., heat resistance of 105 ° C., thickness of 50 μm)
PEN (polyethylene naphthalate): Teonex Q83 (trade name, manufactured by Teijin Limited, heat resistance 150 ° C., thickness 50 μm)
Aramid (aromatic polyamide): Aramica 228S (trade name, manufactured by Teijin Limited, heat resistance 200 ° C., thickness 16 μm)
Glass: Micro slide glass (manufactured by Matsunami Glass Industry Co., Ltd., thickness 1000 μm)
LP paper: Thick glossy paper for color laser printers BP-FG1310 (trade name, manufactured by KOKUYO, thickness 190 μm), when heated at 100 ° C. for 1 hour using an oven, no deterioration such as yellowing occurs confirmed.
PC (polycarbonate): Polyca ace (trade name, manufactured by Sumitomo Bakelite Co., Ltd., heat resistance 120 ° C., thickness 500 μm)

  The substrate was then heated at 100 ° C. for 15 minutes using an oven to produce metallic silver. The diameter of the obtained spot of metallic silver was about 5 mm in Examples 1 to 12 and Comparative Examples 1 to 16, about 2 mm in Example 13, and about 1.5 mm in Example 14.

Subsequently, the surface resistance value of the obtained metallic silver was measured using a tester. The resistance value was measured at two places per one spot of metallic silver, and was measured at ten places in total. The measurement results are shown in Tables 3 and 4. The resistance value is shown as “minimum value to maximum value” in Tables 3 and 4. For example, “1 to 10K” indicates that the minimum value is 1Ω and the maximum value is 10KΩ, “1M to 10M” indicates that the minimum value is 1MΩ and the maximum value is 10MΩ, and “0 .3 "indicates that all measured values were 0.3Ω.
When the resistance value is 3Ω or less, it can be said that the formed metallic silver has high purity and excellent conductivity, and when the resistance value is 1Ω or less, it has particularly excellent characteristics. I can say that.

As shown in Tables 1 to 4, by using the silver ink compositions of Examples 1 to 14 and Reference Examples 1 to 3, the resistance value is low (high conductivity) even at a low temperature of 100 ° C. Metallic silver with good uniformity and good characteristics could be formed.
On the other hand, when the silver ink compositions of Comparative Examples 1 and 2 having a small amount of n-hexylamine and Comparative Examples 3 to 8 having a small amount of dihydric alcohol (2) were used, they were formed. Metallic silver had a large variation in resistance value, the maximum value was remarkably high, and the composition was nonuniform.
Moreover, when using the silver ink composition of Comparative Examples 9-14 in which an alcohol that does not correspond to the dihydric alcohol (2) is blended, it is the same as when using the silver ink compositions of Comparative Examples 1-8. In particular, when the silver ink compositions of Comparative Examples 12 to 14 in which glycerin, ethanol, or ethoxyethanol is blended are used, the resistance value of metallic silver is overloaded (more than the measurable upper limit value) and measured. It became impossible.
The silver ink composition of Comparative Example 15 in which a base other than n-hexylamine was blended, and the silver ink of Comparative Example 16 in which a base other than n-hexylamine and an alcohol not corresponding to the dihydric alcohol (2) were blended. Also when the composition was used, the same results as when the silver ink compositions of Comparative Examples 12 to 14 were used were obtained.

<Production of β-ketocarboxylate (1)>
[Production Example 1]
(Production of silver acetoacetate)
Under water cooling, sodium hydroxide (NaOH) (15.8 g (395.0 mmol)) was dissolved in water (213.8 g), and the temperature of the resulting aqueous sodium hydroxide solution was adjusted to room temperature. The whole amount was added dropwise over 20 minutes to ethyl acetoacetate (51.5 g (395.7 mmol), manufactured by Inoue Fragrance Co., Ltd.), and further stirred overnight at 20 ° C. for hydrolysis.
Then, while cooling the obtained solution containing sodium acetoacetate to 5 to 10 ° C., 69% nitric acid (HNO ₃ ) aqueous solution (1.73 g) was added dropwise over 5 minutes, and the mixture was further stirred for about 10 minutes. did. At this time, the pH of the obtained reaction solution was 5.
Next, silver nitrate (AgNO ₃ ) (47.8 g (281.3 mmol)) was dissolved in water (47.8 g), and the reaction solution having the above pH of 5 was added thereto for 15 minutes while cooling to 5 to 10 ° C. The whole amount was added dropwise and stirred for about 10 minutes to produce silver acetoacetate.
Next, the obtained reaction solution is subjected to centrifugal filtration to separate crystals. The crystals are washed once with water (40 mL), then washed three times with an appropriate amount of ethanol, and dried to obtain the target product. Colorless (white) crystals of silver acetoacetate were obtained (yield 41.2 g, yield 70%).

The obtained silver acetoacetate was subjected to (1) elemental analysis, (2) Fourier transform infrared spectroscopy (FT-IR) and (3) thermal analysis-differential thermogravimetric simultaneous measurement (TG / DTA). (1) Elemental analysis was performed according to a conventional method. Moreover, (2) FT-IR and (3) TG / DTA were respectively performed according to a conventional method under the following conditions using the following apparatuses.
(2) FT-IR
(apparatus)
FT-IR apparatus: Spectrum One / Auto Image FT-IR Spectrometer (Perkin Elmer)
Auxiliary equipment: Universal ATR Sampling Accessory
(conditions)
Measurement range: 4000 to 600 cm ⁻¹
Number of measurements: 4 times Temperature: Room temperature Atmosphere: Air (3) TG / DTA
(apparatus)
Decomposition device: EXSTAR TG / DTA6200 (made by SII Nanotechnology)
(conditions)
Temperature increase rate: 10 ° C / min Temperature range: Room temperature to 200 ° C
Atmosphere: Air

(1) The results of elemental analysis are shown below. As shown here, the analytical values were in good agreement with the theoretical values.
Elemental analysis value: C = 22.9%, H = 2.3%, N = detection limit value (0.4) or less (theoretical values: C = 23.0%, H = 2.4%, N = 0 .0%)
Further, (2) FT-IR spectrum is shown in FIG.
(3) With TG / DTA, the decomposition temperature was 137.4 ° C. And when it heated up to 190 degreeC, the quantity of the residue was 56 mass%, and substantially corresponded with the theoretical quantity (52 mass%) of silver which occupies in one molecule of silver acetoacetate.
From these results, it was confirmed that the obtained product was silver acetoacetate, which was the target product.

[Production Example 2]
(Production of silver isobutyryl acetate)
A 10% aqueous sodium hydroxide solution (70.0 g (sodium hydroxide 175.0 mmol)) was added to methyl isobutyryl acetate (Nippon Seika Co., Ltd., 25.23 g (175.04 mmol)) so as to maintain a temperature of 20 ° C. or less. The mixture was added dropwise over a period of time and further stirred overnight at 20 ° C. for hydrolysis.
Subsequently, 5% nitric acid (22.0 g) was added dropwise thereto while cooling the obtained hydrolysis reaction liquid to 5 to 10 ° C., and the mixture was further stirred for 10 minutes. At this time, the pH of the reaction solution was measured with a pH test paper and found to be 5.
Next, a 25% aqueous silver nitrate solution (95.2 g) is cooled to 15 ° C. or lower, and the entire pH 5 reaction solution is added dropwise over 10 minutes, followed by further stirring for 10 minutes to produce silver isobutyryl acetate. I let you.
Next, the obtained reaction solution is subjected to centrifugal filtration to separate crystals. The crystals are washed once with water (50 mL), then washed 6 times with an appropriate amount of ethanol, and dried to obtain the desired product. Colorless (white) crystals of silver isobutyryl acetate were obtained (yield 24.0 g, yield 72%).

The obtained silver isobutyryl acetate was subjected to (1) elemental analysis, (2) FT-IR and (3) TG / DTA in the same manner as in Production Example 1.
(1) The results of elemental analysis are shown below. As shown here, the analytical values were in good agreement with the theoretical values.
Elemental analysis values: C = 30.4%, H = 3.7%, N = detection limit value (0.4) or less (theoretical values: C = 30.4%, H = 3.8%, N = 0 .0%)
Further, (2) FT-IR spectrum is shown in FIG.
(3) With TG / DTA, the decomposition temperature was 141 ° C. And after heating up to 300 degreeC, when hold | maintaining as it is for 30 minutes, the quantity of a residue is 46.5 mass%, and the theoretical quantity (45.5 mass%) of the silver which occupies in the silver isobutyryl acetate 1 molecule, It was almost the same.
From these results, it was confirmed that the obtained product was silver isobutyryl acetate as the target product.

[Production Example 3]
(Manufacture of silver pivaloyl acetate)
10% aqueous sodium hydroxide solution (70.0 g (sodium hydroxide 175.0 mmol)) was added to methyl pivaloyl acetate (manufactured by Nippon Seika Co., Ltd., 27.69 g (175.08 mmol)) so as to maintain a temperature of 20 ° C. or less. The mixture was added dropwise over a period of time and further stirred overnight at 20 ° C. for hydrolysis.
Subsequently, 5% nitric acid (22.0 g) was added dropwise thereto while cooling the obtained hydrolysis reaction liquid to 5 to 10 ° C., and the mixture was further stirred for 10 minutes. At this time, the pH of the reaction solution was measured with a pH test paper and found to be 5.
Next, a 25% silver nitrate aqueous solution (95.2 g) is cooled to 15 ° C. or lower, and the above-mentioned pH 5 reaction solution is added dropwise over 10 minutes, and 200 g of distilled water is further added dropwise and stirred for 10 minutes. Produced silver pivaloyl acetate.
Next, the obtained reaction solution is subjected to centrifugal filtration to separate crystals. The crystals are washed once with water (50 mL), then washed 6 times with an appropriate amount of ethanol, and dried to obtain the desired product. Colorless (white) crystals of silver pivaloyl acetate ((CH ₃ ) ₃ CC (═O) CH ₂ C (═O) OAg) were obtained (yield 27.4 g, 78% yield).

The obtained silver pivaloyl acetate was subjected to (1) elemental analysis, (2) FT-IR and (3) TG / DTA in the same manner as in Production Example 1.
(1) The results of elemental analysis are shown below. As shown here, the analytical values were in good agreement with the theoretical values.
Elemental analysis values: C = 33.5%, H = 4.4%, N = detection limit value (0.4) or less (theoretical values: C = 33.5%, H = 4.4%, N = 0 .0%)
Further, (2) FT-IR spectrum is shown in FIG.
(3) With TG / DTA, the decomposition temperature was 152 ° C. And after heating up to 300 degreeC, when hold | maintaining as it is for 30 minutes, the quantity of a residue is 42.9 mass%, and the theoretical amount (43.0 mass%) of silver which occupies in one molecule of silver pivaloyl acetate, It was almost the same.
From these results, it was confirmed that the obtained product was silver pivaloyl acetate, which was the target product.

<Manufacture of silver ink composition>
[Example 15]
As shown in Table 5, the silver acetoacetate obtained in Production Example 1 (0.5 g, 2.39 mmol), n-hexylamine (0.97 g, 9.60 mmol), and ethylene glycol (0.64 g, 10 .33 mmol) was mixed while cooling with ice water to prepare a silver ink composition.

[Examples 16 to 22]
A silver ink composition was produced in the same manner as in Example 15 except that the amounts of n-hexylamine and ethylene glycol used were as shown in Table 5.

[Example 23]
As shown in Table 5, silver isobutyryl acetate (0.5 g, 2.11 mmol), n-hexylamine (0.85 g, 8.42 mmol) obtained in Production Example 2 and ethylene glycol (0.65 g, 10 .50 mmol) was mixed while cooling with ice water to prepare a silver ink composition.

[Example 24]
As shown in Table 5, silver pivaloyl acetate (0.5 g, 1.99 mmol), n-hexylamine (0.80 g, 7.92 mmol) obtained in Production Example 3 and ethylene glycol (0.62 g, 10 .01 mmol) was mixed while cooling with ice water to prepare a silver ink composition.

[Comparative Examples 17 to 32]
As shown in Table 6, a silver ink composition was produced in the same manner as Example 15 except that the types and amounts of silver β-ketocarboxylate (1), base and alcohol were set.

<Manufacture of metallic silver>
Similarly to Examples 1 to 14, metallic silver was produced on a PET substrate using the silver ink compositions of Examples 15 to 24 and Comparative Examples 17 to 32, and the surface resistance value was measured. The results are shown in Tables 7 and 8.

As shown in Tables 5 to 8, even when using the silver ink compositions of Examples 15 to 24 containing β-ketocarboxylate (1) other than silver 2-methylacetoacetate, at a low temperature of 100 ° C., It was possible to form metallic silver having good characteristics with low resistance (high conductivity) and high composition uniformity.
On the other hand, Comparative Examples 17 to 20 with a small amount of dihydric alcohol (2), Comparative Examples 21 to 26 and 28 to 32 in which an alcohol other than ethylene glycol was blended, and bases other than n-hexylamine When the blended silver ink composition of Comparative Example 27 was used, the formed metallic silver had a large variation in resistance value, and the maximum value was extremely high, and the composition was nonuniform. In particular, when the silver ink composition of Comparative Examples 23, 25 and 26 in which glycerin, ethanol or ethoxyethanol was blended as an alcohol, or the silver ink composition of Comparative Example 27 in which n-octylamine was blended as a base was used. The metal silver resistance value was overloaded (more than the measurable upper limit value), making measurement impossible.

  The present invention can be used for the production of metallic silver as a recording material, a printing plate material, and a highly conductive material.

Claims (1)

One or more β -ketocarboxylates selected from the group consisting of silver 2-methylacetoacetate, silver acetoacetate, silver isobutyrylacetate and silver pivaloylacetate , n-hexylamine and ethylene glycol are blended,
The compounding amount of the n-hexylamine per 1 mol of the β-ketocarboxylate compound is 2.5 mol or more,
The silver ink composition, wherein a blending amount of the ethylene glycol per mole of the β-ketocarboxylate is 1 mol.