JP6712949B2 - Metallic silver, method for producing metallic silver, and laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to metallic silver, a method for producing the same, and a laminated body provided with a layer made of the metallic silver on a substrate.
The present application claims priority based on Japanese Patent Application No. 2014-197818 filed in Japan on September 29, 2014, and the content thereof is incorporated herein.

A laminated body having a patterned silver layer provided on a base material is used for constituting wirings, electrodes, antennas and the like in electronic devices such as communication devices.
The silver layer is formed by, for example, preparing a silver ink composition containing metallic silver or a material for forming the same, depositing the composition on a substrate, and heating (baking) the deposited composition. To be done. In recent years, since it is easy to form a silver layer having good characteristics, a method of forming metallic silver using a silver ink composition containing a metallic silver forming material, rather than metallic silver itself, has been widely used. Is coming.

Such a silver ink composition includes a metal complex compound obtained by reacting one or more metals or metal compounds with one or more specific ammonium carbamate- or ammonium carbonate-based compounds, and an additive. A conductive ink composition containing silver and the metal is silver is disclosed (see Patent Document 1).

However, the silver ink composition disclosed in Patent Document 1 has a heating (baking) temperature of 130° C. or higher necessary for forming metallic silver having sufficient conductivity, and the base material used has a certain degree of heat resistance. However, there is a problem that the material of the base material is limited.

Japanese Patent Publication No. 2008-531810

The present invention provides metallic silver that can be obtained by heat treatment at a lower temperature and has sufficient conductivity, a method for producing the same, and a laminate having a layer of the metallic silver on a substrate. This is an issue.

The present invention provides metallic silver having a crystallite diameter of 15 nm or more and a volume resistivity of 8 μΩ·cm or less.
The metallic silver of the present invention may have the crystallite size of 16.5 nm or more and 80 nm or less.

The metallic silver of the present invention may be formed using silver β-ketocarboxylate represented by the following general formula (1).

（式中、Ｒは１個以上の水素原子が置換基で置換されていてもよい炭素数１〜２０の脂肪族炭化水素基若しくはフェニル基、水酸基、アミノ基、又は一般式「Ｒ^１−ＣＹ^１ _２−」、「ＣＹ^１ _３−」、「Ｒ^１−ＣＨＹ^１−」、「Ｒ^２Ｏ−」、「Ｒ^５Ｒ^４Ｎ−」、「（Ｒ^３Ｏ）_２ＣＹ^１−」若しくは「Ｒ^６−Ｃ（＝Ｏ）−ＣＹ^１ _２−」で表される基であり；
Ｙ^１はそれぞれ独立にフッ素原子、塩素原子、臭素原子又は水素原子であり；Ｒ^１は炭素数１〜１９の脂肪族炭化水素基又はフェニル基であり；Ｒ^２は炭素数１〜２０の脂肪族炭化水素基であり；Ｒ^３は炭素数１〜１６の脂肪族炭化水素基であり；Ｒ^４及びＲ^５はそれぞれ独立に炭素数１〜１８の脂肪族炭化水素基であり；Ｒ^６は炭素数１〜１９の脂肪族炭化水素基、水酸基又は式「ＡｇＯ−」で表される基であり；
Ｘ^１はそれぞれ独立に水素原子、炭素数１〜２０の脂肪族炭化水素基、ハロゲン原子、１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはベンジル基、シアノ基、Ｎ−フタロイル−３−アミノプロピル基、２−エトキシビニル基、又は一般式「Ｒ^７Ｏ−」、「Ｒ^７Ｓ−」、「Ｒ^７−Ｃ（＝Ｏ）−」若しくは「Ｒ^７−Ｃ（＝Ｏ）−Ｏ−」で表される基であり；
Ｒ^７は、炭素数１〜１０の脂肪族炭化水素基、チエニル基、又は１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはジフェニル基である。）

(In the formula, R is an aliphatic hydrocarbon group having 1 to 20 carbon atoms in which one or more hydrogen atoms may be substituted with a substituent, a phenyl group, a hydroxyl group, an amino group, or a general formula “R ¹ -CY”. ¹ ₂ - "," ^CY _{1 3} - "," ^R 1 -CHY ¹ - "," ^{R 2} O - "," ^R 5 ^{R 4} N -, "" _{^{(R 3 O) 2 CY 1}} - "or" ^{R 6 -C (= O) -CY} 1 2 - be a group represented by ";
Y ¹ is each independently a fluorine atom, a chlorine atom, a bromine atom or a hydrogen atom; R ¹ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group; R ² is a fat having 1 to 20 carbon atoms R ³ is an aliphatic hydrocarbon group having 1 to 16 carbon atoms; R ⁴ and R ⁵ are each independently an aliphatic hydrocarbon group having 1 to 18 carbon atoms; R ⁶ is An aliphatic hydrocarbon group having 1 to 19 carbon atoms, a hydroxyl group or a group represented by the formula "AgO-";
X ¹ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a phenyl group in which one or more hydrogen atoms may be substituted with a substituent, a benzyl group, a cyano group, N - phthaloyl-3-aminopropyl group, 2-ethoxyethyl vinyl group, or the general formula ^{"R 7} O -", ^{"R 7} S -", ^"R 7 -C (= O) -" or ^"R 7 -C ( =O)-O-";
R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group, or a phenyl group or diphenyl group in which one or more hydrogen atoms may be substituted with a substituent. )

Further, the present invention uses the β-ketocarboxylate represented by the following general formula (1) to form metallic silver having a crystallite diameter of 15 nm or more and a volume resistivity of 8 μΩ·cm or less. There is provided a method for producing metallic silver, the method including:

（式中、Ｒは１個以上の水素原子が置換基で置換されていてもよい炭素数１〜２０の脂肪族炭化水素基若しくはフェニル基、水酸基、アミノ基、又は一般式「Ｒ^１−ＣＹ^１ _２−」、「ＣＹ^１ _３−」、「Ｒ^１−ＣＨＹ^１−」、「Ｒ^２Ｏ−」、「Ｒ^５Ｒ^４Ｎ−」、「（Ｒ^３Ｏ）_２ＣＹ^１−」若しくは「Ｒ^６−Ｃ（＝Ｏ）−ＣＹ^１ _２−」で表される基であり；
Ｙ^１はそれぞれ独立にフッ素原子、塩素原子、臭素原子又は水素原子であり；Ｒ^１は炭素数１〜１９の脂肪族炭化水素基又はフェニル基であり；Ｒ^２は炭素数１〜２０の脂肪族炭化水素基であり；Ｒ^３は炭素数１〜１６の脂肪族炭化水素基であり；Ｒ^４及びＲ^５はそれぞれ独立に炭素数１〜１８の脂肪族炭化水素基であり；Ｒ^６は炭素数１〜１９の脂肪族炭化水素基、水酸基又は式「ＡｇＯ−」で表される基であり；
Ｘ^１はそれぞれ独立に水素原子、炭素数１〜２０の脂肪族炭化水素基、ハロゲン原子、１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはベンジル基、シアノ基、Ｎ−フタロイル−３−アミノプロピル基、２−エトキシビニル基、又は一般式「Ｒ^７Ｏ−」、「Ｒ^７Ｓ−」、「Ｒ^７−Ｃ（＝Ｏ）−」若しくは「Ｒ^７−Ｃ（＝Ｏ）−Ｏ−」で表される基であり；
Ｒ^７は、炭素数１〜１０の脂肪族炭化水素基、チエニル基、又は１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはジフェニル基である。）
本発明の金属銀の製造方法においては、前記金属銀を形成する工程において、前記β−ケトカルボン酸銀が配合されてなる銀インク組成物を、非加湿条件下で加熱処理した後、さらに加湿条件下で、又は加熱した液体と接触させて、加熱処理することで前記金属銀を形成してもよい。

(In the formula, R is an aliphatic hydrocarbon group having 1 to 20 carbon atoms in which one or more hydrogen atoms may be substituted with a substituent, a phenyl group, a hydroxyl group, an amino group, or a general formula “R ¹ -CY”. ¹ ₂ - "," ^CY _{1 3} - "," ^R 1 -CHY ¹ - "," ^{R 2} O - "," ^R 5 ^{R 4} N -, "" _{^{(R 3 O) 2 CY 1}} - "or" ^{R 6 -C (= O) -CY} 1 2 - be a group represented by ";
Y ¹ is each independently a fluorine atom, a chlorine atom, a bromine atom or a hydrogen atom; R ¹ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group; R ² is a fat having 1 to 20 carbon atoms R ³ is an aliphatic hydrocarbon group having 1 to 16 carbon atoms; R ⁴ and R ⁵ are each independently an aliphatic hydrocarbon group having 1 to 18 carbon atoms; R ⁶ is An aliphatic hydrocarbon group having 1 to 19 carbon atoms, a hydroxyl group or a group represented by the formula "AgO-";
X ¹ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a phenyl group in which one or more hydrogen atoms may be substituted with a substituent, a benzyl group, a cyano group, N - phthaloyl-3-aminopropyl group, 2-ethoxyethyl vinyl group, or the general formula ^{"R 7} O -", ^{"R 7} S -", ^"R 7 -C (= O) -" or ^"R 7 -C ( =O)-O-";
R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group, or a phenyl group or diphenyl group in which one or more hydrogen atoms may be substituted with a substituent. )
In the method for producing metallic silver of the present invention, in the step of forming the metallic silver, a silver ink composition containing the silver β-ketocarboxylate is heat-treated under non-humidified conditions, and then further humidified conditions. The metallic silver may be formed by heat treatment below or in contact with a heated liquid.

The present invention also provides a laminate having a layer of the metallic silver on a substrate.
In the laminate of the present invention, the base material may have a thickness of 0.5 to 5000 μm, and the metal silver layer may have a thickness of 0.01 to 5 μm.
In the laminate of the present invention, the base material may have a deflection temperature under load of 120° C. or less when the deflection amount is 0.25 mm at a bending stress of 1.8 MPa as defined by ASTM D648. Good.

The metallic silver of the present invention can be obtained by heat treatment at a lower temperature, has sufficient conductivity, and can form a laminate having a layer of the metallic silver on a substrate.

It is sectional drawing which shows an example of the laminated body of this invention typically.

Preferred examples of the metallic silver of the present invention, a method for producing the same, and a laminate will be described below. However, the present invention is not limited to these examples, and for example, additions, omissions, substitutions, and other changes (amount, number, position, size, etc.) can be made without departing from the spirit of the present invention. Is.

<< metallic silver >>
The metallic silver of the present invention has a crystallite diameter of 15 nm or more and a volume resistivity of 8 μΩ·cm or less.
The metallic silver has a crystallite diameter of 15 nm or more even when it is formed by subjecting the composition for forming it to a low temperature of less than 130° C. and performing a post-treatment such as a drying treatment or a heating (baking) treatment. Since it is made of a material, it has a volume resistivity of 8 μΩ·cm or less and has sufficiently high conductivity.

The crystallite diameter of metallic silver can be determined by a known method. For example, metallic silver is subjected to X-ray diffraction measurement, and from the measurement result of the obtained X-ray diffraction peak, regarding the peak of the crystal plane having the highest intensity, Scherrer's formula “D=kλ/β cos θ (where D is a crystallite diameter (nm); k is a constant (0.9 is used here); λ is an X-ray wavelength (CuKα ray) 0.154 nm; β is a peak half width (rad). , Θ is an angle that is ½ of the measurement angle.)” can be used to calculate the crystallite diameter of metallic silver.
The X-ray diffraction measurement can be performed using, for example, a thin film X-ray diffractometer.

The crystallite diameter of the metallic silver is 15 nm or more, preferably 15.5 nm or more, more preferably 16 nm or more, and particularly preferably 16.5 nm or more.
The upper limit of the crystallite diameter of the metallic silver is not particularly limited, but is preferably 80 nm because the degree of increase in the effect of the present invention obtained is limited with respect to the increase of the crystallite diameter. , 70 nm is more preferable, and it may be 40 nm or the like, but is not limited thereto.

The volume resistivity of the metallic silver is 8 μΩ·cm or less, and for example, it can be set to any one of 7.6 μΩ·cm or less, 7.3 μΩ·cm or less, and 7 μΩ·cm or less.
On the other hand, the volume resistivity of the metallic silver is preferably as low as possible, and the lower limit thereof is not particularly limited, but can be, for example, either 1.59 μΩ·cm or 2.5 μΩ·cm.
The volume resistivity of the metallic silver usually tends to decrease as the crystallite diameter of the metallic silver increases.

<<Method for producing metallic silver>>
With respect to the metallic silver, a composition (silver ink composition) for forming the metallic silver is prepared, and the composition is adhered to a desired portion such as a base material described later, and a solidification treatment such as a drying treatment or a heating (baking) treatment. Can be manufactured by appropriately selecting. The heat treatment may be combined with the drying treatment.

<Silver ink composition>
In the present invention, it is preferable to use, as the silver ink composition, a silver ink composition containing a metal silver forming material.
The metal silver forming material to be blended may be only one kind or two or more kinds, and in the case of two or more kinds, the combination and the ratio can be arbitrarily adjusted.

The material for forming metallic silver may be any material as long as it has a silver atom (element) and produces metallic silver by a structural change such as decomposition, a silver salt, a silver complex, an organic silver compound (a compound having a silver-carbon bond). ) Etc. can be illustrated. The silver salt and the silver complex may be either a silver compound having an organic group or a silver compound having no organic group. Among them, the metal silver forming material is preferably a silver salt.
By using a forming material of metallic silver, metallic silver is produced from the material. The metallic silver in this case has a high purity, and the ratio of metallic silver is high enough to be regarded as consisting of metallic silver only, and the ratio of metallic silver is preferably 97% by mass or more, and more preferably 98% by mass. % Or more, particularly preferably 99% by mass or more. The upper limit of the ratio of metallic silver is, for example, 100% by mass, 99.9% by mass, 99.8% by mass, 99.7% by mass, 99.6% by mass, 99.5% by mass, 99.4% by mass. , 99.3% by mass, 99.2% by mass and 99.1% by mass, but is not limited thereto.

The silver ink composition is preferably a liquid one, and is preferably one in which a metal silver forming material is dissolved or uniformly dispersed.

[Silver carboxylate]
Examples of the material for forming metallic silver include silver carboxylate having a group represented by the formula “—COOAg”. Such silver carboxylate is suitable for forming metallic silver having a crystallite size of 15 nm or more. It is something.
In the present invention, one type of silver carboxylate may be used alone, or two or more types may be used in combination. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.
The silver carboxylate is not particularly limited as long as it has a group represented by the formula “—COOAg”. For example, the number of groups represented by the formula “—COOAg” may be only one, or may be two or more. Further, the position of the group represented by the formula “—COOAg” in silver carboxylate is also not particularly limited.

The silver carboxylate is represented by silver β-ketocarboxylate represented by the following general formula (1) (hereinafter sometimes abbreviated as “β-ketocarboxylate silver (1)”) and the following general formula (4). It is preferable that at least one selected from the group consisting of silver carboxylate (hereinafter, may be abbreviated as “silver carboxylate (4)”).
In the present specification, the term “silver carboxylate” means not only “β-ketocarboxylate silver (1)” and “silver carboxylate (4)” but also these unless otherwise specified. It is meant to encompass "silver carboxylate having a group represented by the formula "-COOAg"".

（式中、Ｒは１個以上の水素原子が置換基で置換されていてもよい炭素数１〜２０の脂肪族炭化水素基若しくはフェニル基、水酸基、アミノ基、又は一般式「Ｒ^１−ＣＹ^１ _２−」、「ＣＹ^１ _３−」、「Ｒ^１−ＣＨＹ^１−」、「Ｒ^２Ｏ−」、「Ｒ^５Ｒ^４Ｎ−」、「（Ｒ^３Ｏ）_２ＣＹ^１−」若しくは「Ｒ^６−Ｃ（＝Ｏ）−ＣＹ^１ _２−」で表される基であり；
Ｙ^１はそれぞれ独立にフッ素原子、塩素原子、臭素原子又は水素原子であり；Ｒ^１は炭素数１〜１９の脂肪族炭化水素基又はフェニル基であり；Ｒ^２は炭素数１〜２０の脂肪族炭化水素基であり；Ｒ^３は炭素数１〜１６の脂肪族炭化水素基であり；Ｒ^４及びＲ^５はそれぞれ独立に炭素数１〜１８の脂肪族炭化水素基であり；Ｒ^６は炭素数１〜１９の脂肪族炭化水素基、水酸基又は式「ＡｇＯ−」で表される基であり；
Ｘ^１はそれぞれ独立に水素原子、炭素数１〜２０の脂肪族炭化水素基、ハロゲン原子、１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはベンジル基、シアノ基、Ｎ−フタロイル−３−アミノプロピル基、２−エトキシビニル基、又は一般式「Ｒ^７Ｏ−」、「Ｒ^７Ｓ−」、「Ｒ^７−Ｃ（＝Ｏ）−」若しくは「Ｒ^７−Ｃ（＝Ｏ）−Ｏ−」で表される基であり；
Ｒ^７は、炭素数１〜１０の脂肪族炭化水素基、チエニル基、又は１個以上の水素原子が置換基で置換されていてもよいフェニル基若しくはジフェニル基である。）

(In the formula, R is an aliphatic hydrocarbon group having 1 to 20 carbon atoms in which one or more hydrogen atoms may be substituted with a substituent, a phenyl group, a hydroxyl group, an amino group, or a general formula “R ¹ -CY”. ¹ ₂ - "," ^CY _{1 3} - "," ^R 1 -CHY ¹ - "," ^{R 2} O - "," ^R 5 ^{R 4} N -, "" _{^{(R 3 O) 2 CY 1}} - "or" ^{R 6 -C (= O) -CY} 1 2 - be a group represented by ";
Y ¹ is each independently a fluorine atom, a chlorine atom, a bromine atom or a hydrogen atom; R ¹ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group; R ² is a fat having 1 to 20 carbon atoms R ³ is an aliphatic hydrocarbon group having 1 to 16 carbon atoms; R ⁴ and R ⁵ are each independently an aliphatic hydrocarbon group having 1 to 18 carbon atoms; R ⁶ is An aliphatic hydrocarbon group having 1 to 19 carbon atoms, a hydroxyl group or a group represented by the formula "AgO-";
X ¹ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a phenyl group in which one or more hydrogen atoms may be substituted with a substituent, a benzyl group, a cyano group, N - phthaloyl-3-aminopropyl group, 2-ethoxyethyl vinyl group, or the general formula ^{"R 7} O -", ^{"R 7} S -", ^"R 7 -C (= O) -" or ^"R 7 -C ( =O)-O-";
R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group, or a phenyl group or diphenyl group in which one or more hydrogen atoms may be substituted with a substituent. )

（式中、Ｒ^８は炭素数１〜１９の脂肪族炭化水素基、カルボキシ基又は式「−Ｃ（＝Ｏ）−ＯＡｇ」で表される基であり、前記脂肪族炭化水素基がメチレン基を有する場合、１個以上の前記メチレン基はカルボニル基で置換されていてもよい。）

(In the formula, R ⁸ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms, a carboxy group or a group represented by the formula “—C(═O)—OAg”, and the aliphatic hydrocarbon group is a methylene group. , One or more of the methylene groups may be substituted with a carbonyl group.)

(Silver β-ketocarboxylate (1))
The β-ketocarboxylate (1) is represented by the general formula (1), and is more suitable for forming metallic silver having a crystallite size of 15 nm or more.
In the formula, R is an aliphatic hydrocarbon group having 1 to 20 carbon atoms in which one or more hydrogen atoms may be substituted with a substituent, a phenyl group, a hydroxyl group, an amino group, or the general formula “R ¹ -CY ¹ ₂ - "," ^CY _{1 3} - "," ^R 1 -CHY ¹ - "," ^{R 2} O - "," ^R 5 ^{R 4} N -, "" _{^{(R 3 O) 2 CY 1}} - "or" R _{^{6 -C (= O) -CY 1}} 2 - "a group represented by.

The aliphatic hydrocarbon group having 1 to 20 carbon atoms in R may be linear, branched or cyclic (aliphatic cyclic group), and when cyclic, may be monocyclic or polycyclic. .. Further, the aliphatic hydrocarbon group may be either a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms. Examples of the preferable aliphatic hydrocarbon group for R include an alkyl group, an alkenyl group, and an alkynyl group.

Examples of the linear or branched alkyl group for R include methyl group, ethyl group, 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, 2-methylbutyl group, n-hexyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4- Methylpentyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 3-ethylbutyl group , 1-ethyl-1-methylpropyl group, n-heptyl group, 1-methylhexyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1,1- Dimethylpentyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,3-dimethylpentyl group, 4,4-dimethylpentyl group, 1-ethylpentyl group, 2-ethylpentyl group, 3-ethylpentyl group, 4-ethylpentyl group, 2,2,3-trimethylbutyl group, 1-propylbutyl group, n-octyl group, isooctyl group, 1-methylheptyl group, 2- Methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 1-ethylhexyl group, 2-ethylhexyl group, 3-ethylhexyl group, 4-ethylhexyl group, 5-ethylhexyl group, 1,1 -Dimethylhexyl group, 2,2-dimethylhexyl group, 3,3-dimethylhexyl group, 4,4-dimethylhexyl group, 5,5-dimethylhexyl group, 1-propylpentyl group, 2-propylpentyl group, nonyl Examples include groups, decyl groups, undecyl groups, dodecyl groups, tridecyl groups, tetradecyl groups, pentadecyl groups, hexadecyl groups, heptadecyl groups, octadecyl groups, nonadecyl groups, and icosyl groups.
Examples of the cyclic alkyl group for R include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, isobornyl group, 1-adamantyl group, 2- Examples thereof include an adamantyl group and a tricyclodecyl group.

Examples of the alkenyl group for R, a vinyl group (ethenyl group, -CH = _CH 2), allyl (2-propenyl _{group, -CH 2 -CH = CH 2)} , 1- propenyl group (-CH = CH-CH _3), isopropenyl _{(-C (CH 3) = CH} 2), 1- butenyl group _{(-CH = CH-CH 2 -CH} 3), 2- butenyl group _{(-CH 2 -CH = CH-CH} 3 ), 3-butenyl group _{(-CH 2 -CH 2 -CH = CH} 2), cyclohexenyl group, such as cyclopentenyl group, one single bond between carbon atoms of the alkyl group in R (C-C) A group in which is substituted with a double bond (C=C) can be exemplified.
The alkynyl group for R is one single bond (C—C) between the carbon atoms of the alkyl group for R, such as an ethynyl group (—C≡CH) and a propargyl group (—CH ₂ —C≡CH). A group in which) is substituted with a triple bond (C≡C) can be exemplified.

In the aliphatic hydrocarbon group having 1 to 20 carbon atoms in R, one or more hydrogen atoms may be substituted with a substituent, and as the preferable substituent, a fluorine atom, a chlorine atom and a bromine atom can be exemplified. .. Moreover, the number and position of the substituents are not particularly limited. When the number of substituents is plural, these plural substituents may be the same or different from each other. That is, all the substituents may be the same, all the substituents may be different, or only some of the substituents may be different.

The phenyl group in R may have one or more hydrogen atoms substituted with a substituent, and the preferable substituent is a saturated or unsaturated monovalent aliphatic hydrocarbon group having 1 to 16 carbon atoms. A monovalent group in which the aliphatic hydrocarbon group is bonded to an oxygen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group (-OH), a cyano group (-C≡N), a phenoxy group (-O- C ₆ H ₅ ) and the like can be exemplified, and the number and position of the substituents are not particularly limited. When the number of substituents is plural, these plural substituents may be the same or different from each other.
As the aliphatic hydrocarbon group which is a substituent, the same aliphatic hydrocarbon group as R can be exemplified except that the aliphatic hydrocarbon group has 1 to 16 carbon atoms.

Each Y ^{1 in} R is independently a fluorine atom, a chlorine atom, a bromine atom or a hydrogen atom. Then, the general formula ^"R ₁ ^-CY 1 ₂ -", ^"CY _{1 3} -" and ^{"R 6 -C (= O) -CY} 1 2 - " In a plurality of ^{Y 1} are each, also identical to one another It may be different.

R ¹ in R is an aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group (C ₆ H ₅ —), and the aliphatic hydrocarbon group for R ¹ has 1 to 19 carbon atoms. Except for the point, the same as the above-mentioned aliphatic hydrocarbon group for R can be exemplified.
R ² in R is an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and examples thereof include the same as the above aliphatic hydrocarbon group in R.
R ³ in R is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, and examples thereof include the same as the above aliphatic hydrocarbon group in R, except that the number of carbon atoms is 1 to 16.
R ⁴ and R ⁵ in R are each independently an aliphatic hydrocarbon group having 1 to 18 carbon atoms. That is, R ⁴ and R ⁵ may be the same as or different from each other, and examples thereof are the same as those of the aliphatic hydrocarbon group for R except that the carbon number is 1 to 18.
R ⁶ in R is an aliphatic hydrocarbon group having 1 to 19 carbon atoms, a hydroxyl group or a group represented by the formula “AgO—”, and the aliphatic hydrocarbon group for R ⁶ has 1 to 10 carbon atoms. Except that it is 19, the same as the aliphatic hydrocarbon group for R can be exemplified.

R is, among these, a linear or branched alkyl group, the general formula ^{"R 6 -C (= O) -CY} 1 2 - " group represented by be a hydroxyl group or a phenyl group preferable. R ⁶ is preferably a linear or branched alkyl group, a hydroxyl group, or a group represented by the formula “AgO—”.

In the general formula (1), X ¹ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a phenyl group in which one or more hydrogen atoms may be substituted with a substituent, or benzyl _{(C 6 H 5 -CH 2 -} ), cyano group, N- phthaloyl-3-aminopropyl group, 2-ethoxyethyl vinyl group _{(C 2 H 5 -O-CH} = CH-), or the general formula "R ⁷ O-", "R ⁷ S-", "R ⁷ -C(=O)-" or "R ⁷ -C(=O)-O-".
Examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms for X ¹ include the same as the aliphatic hydrocarbon group for R.

Examples of the halogen atom for X ¹ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
In the phenyl group and the benzyl group for X ¹ , one or more hydrogen atoms may be substituted with a substituent, and as the preferable substituent, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), nitro group (-NO ₂₎ or the like can be exemplified, the number and position of the substituent is not particularly limited. When the number of substituents is plural, these plural substituents may be the same or different from each other.

R ⁷ in X ¹ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group (C ₄ H ₃ S-), or a phenyl group in which one or more hydrogen atoms may be substituted with a substituent, or diphenyl group (biphenyl _{group, C 6 H 5 -C 6 H} 4 -) is. Examples of the aliphatic hydrocarbon group for R ⁷ include the same ones as the aliphatic hydrocarbon group for R, except that the number of carbon atoms is 1 to 10. Further, examples of the substituent of the phenyl group and diphenyl group in R ⁷ include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom) and the like, and the number and position of the substituents are not particularly limited. When the number of substituents is plural, these plural substituents may be the same or different from each other.
When R ⁷ is a thienyl group or a diphenyl group, the bonding position of these groups with the adjacent group or atom in X ¹ (oxygen atom, sulfur atom, carbonyl group, carbonyloxy group) is not particularly limited. For example, the thienyl group may be either a 2-thienyl group or a 3-thienyl group.

In the general formula (1), two X ^1's may be bound as a single group via a double bond with a carbon atom sandwiched by two carbonyl groups, and as such a group, groups represented by the formula _{"= CH-C 6 H 4 -NO} 2 " may be exemplified.

Among the above, X ¹ is preferably a hydrogen atom, a linear or branched alkyl group, a benzyl group, or a group represented by the general formula “R ⁷ —C(═O)—”. It is preferable that at least one X ¹ is a hydrogen atom.

Silver β-ketocarboxylate (1) includes silver 2-methylacetoacetate (CH ₃ -C(=O)-CH(CH ₃ )-C(=O)-OAg) and silver acetoacetate (CH ₃ -C(= _{O) -CH 2 -C (= O} ) -OAg), 2- ethylacetoacetate silver _{(CH 3 -C (= O)} -CH (CH 2 CH 3) -C (= O) -OAg), propionyl silver acetate _{(CH 3 CH 2 -C (=} O) -CH 2 -C (= O) -OAg), isobutyryl silver acetate _{((CH 3) 2 CH-} C (= O) -CH 2 -C (= O) - OAg), silver pivaloylacetate _{((CH 3) 3 C-} C (= O) -CH 2 -C (= O) -OAg), caproyl silver acetate _{(CH 3 (CH 2) 3} CH 2 -C (= O _{) -CH 2 -C (= O)} -OAg), 2-n- Buchiruaseto silver acetate _{(CH 3 -C (= O)} -CH (CH 2 CH 2 CH 2 CH 3) -C (= O) -OAg ), 2-benzyl acetoacetate silver _{(CH 3 -C (= O)} -CH (CH 2 C 6 H 5) -C (= O) -OAg), silver benzoylacetate _{(C 6 H 5 -C (=} O _{) -CH 2 -C (= O)} -OAg), Pibaroiruaseto silver acetate _{((CH 3) 3 C-} C (= O) -CH 2 -C (= O) -CH 2 -C (= O) -OAg ), isobutyryl acetoacetate silver _{((CH 3) 2 CH-} C (= O) -CH 2 -C (= O) -CH 2 -C (= O) -OAg), 2- acetyl pivaloyl acetate silver _{((CH 3) 3 C-} C (= O) -CH (-C (= O) -CH 3) -C (= O) -OAg), 2- acetyl isobutyryl silver acetate _((CH 3) _{2 CH-C (= O)} -CH (-C (= O) -CH 3) -C (= O) -OAg), or acetone dicarboxylic silver (AgO-C (= O) -CH 2 -C ( = _O) is preferably -CH 2 -C (= O) -OAg ).

The β-ketocarboxylate silver (1) can further reduce the concentration of remaining raw materials and impurities in the conductor (metal silver) formed by the solidification treatment such as the drying treatment or the heating (baking) treatment. The less the raw materials and impurities are, the better the contact between the formed metal silver particles is, the easier the conduction is, and the lower the resistivity is.

As described below, the β-ketocarboxylate silver (1) decomposes at a low temperature of preferably 60 to 210°C, more preferably 60 to 200°C, without using a reducing agent or the like known in the art, It is possible to form metallic silver. When it is used in combination with a reducing agent, it decomposes at a lower temperature to form metallic silver. The reducing agent will be described later.

In the present invention, one type of silver β-ketocarboxylate (1) may be used alone, or two or more types may be used in combination. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

(Silver carboxylate (4))
Silver carboxylate (4) is represented by the general formula (4), and is more suitable for forming metallic silver having a crystallite size of 15 nm or more.
In the formula, R ⁸ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms, a carboxy group (—COOH), or a group represented by the formula “—C(═O)—OAg”.
Examples of the aliphatic hydrocarbon group for R ⁸ include those similar to the aliphatic hydrocarbon group for R, except that the aliphatic hydrocarbon group for R ⁸ has 1 to 19 carbon atoms. However, the aliphatic hydrocarbon group for R ⁸ preferably has 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms.

When the aliphatic hydrocarbon group for R ⁸ has a methylene group (—CH ₂ —), one or more methylene groups may be substituted with a carbonyl group. The number and position of the methylene group that may be substituted with a carbonyl group is not particularly limited, and all methylene groups may be substituted with a carbonyl group. Here, the "methylene group" is not only a group represented by the formula "-CH ₂ -" alone, but also one in an alkylene group in which a plurality of groups represented by the formula "-CH ₂ -" are linked. The group represented by the formula “—CH ₂ —” is also included.

Silver carboxylate (4), pyruvic silver _{(CH 3 -C (= O)} -C (= O) -OAg), silver acetate _{(CH 3 -C (= O)} -OAg), silver butyrate (CH _{3 - (CH 2) 2 -C (} = O) -OAg), isobutyric acid silver _{((CH 3) 2 CH-} C (= O) -OAg), hexane silver 2-ethylhexyl _(CH 3 - _{(CH 2 ) 3 -CH (CH 2 CH 3} ) -C (= O) -OAg), silver neodecanoate _{(CH 3 - (CH 2)} 5 -C (CH 3) 2 -C (= O) -OAg), oxalic silver (AgO-C (= O) -C (= O) -OAg), or is preferably a malonate silver _{(AgO-C (= O)} -CH 2 -C (= O) -OAg). Also, 2 of the silver oxalate (AgO-C (= O) -C (= O) -OAg) and malonic silver _{(AgO-C (= O)} -CH 2 -C (= O) -OAg) Of the groups represented by the formula "-COOAg", one of the groups represented by the formula "-COOH" (HO-C(=O)-C(=O)-OAg, HO _{-C (= O) -CH 2 -C} (= O) -OAg) it is also preferred.

Similarly to silver β-ketocarboxylate (1), silver carboxylate (4) also contains residual raw materials and impurities in the conductor (metallic silver) formed by solidification treatment such as drying treatment and heating (baking) treatment. The concentration can be further reduced. When it is used in combination with a reducing agent, it decomposes at a lower temperature to form metallic silver.

In the present invention, one type of silver carboxylate (4) may be used alone, or two or more types may be used in combination. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

The silver carboxylate is silver 2-methylacetoacetate, silver acetoacetate, silver 2-ethylacetoacetate, silver propionyl acetate, silver isobutyryl acetate, silver pivaloyl acetate, silver caproyl acetate, silver 2-n-butylacetoacetate, 2-benzylacetate. Silver acetate, silver benzoylacetate, silver pivaloylacetoacetate, silver isobutyrylacetoacetate, silver acetonedicarboxylate, silver pyruvate, silver acetate, silver butyrate, silver isobutyrate, silver 2-ethylhexanoate, silver neodecanoate, shu It is preferably one or more selected from the group consisting of silver acid salts and silver malonates.
Among these silver carboxylates, silver 2-methylacetoacetate and silver acetoacetate have excellent compatibility with the nitrogen-containing compounds (among others, amine compounds) described later, and are particularly suitable for increasing the concentration of the silver ink composition. It is mentioned as a thing.

In the silver ink composition, the content of silver derived from the material for forming metallic silver is preferably 5% by mass or more, and more preferably 10% by mass or more. Within such a range, the formed conductor (metal silver) becomes more excellent in quality. The upper limit of the silver content is not particularly limited as long as the effects of the present invention are not impaired, but it is preferably 25% by mass in consideration of handleability and the like.
In the present specification, the term “silver derived from a material for forming metallic silver” means silver in the material for forming metallic silver blended during the production of a silver ink composition, unless otherwise specified. It is a concept that includes both silver that is a constituent of the metallic silver forming material after the compounding and silver and silver itself in the decomposed product generated by the decomposition of the metallic silver forming material after the compounding.

[Nitrogen-containing compound]
The silver ink composition is preferably a composition containing a nitrogen-containing compound in addition to the metal silver forming material, particularly when the metal silver forming material is the silver carboxylate. The nitrogen-containing compound is preferably used in order to form metallic silver having a crystallite size of 15 nm or more.
The nitrogen-containing compound is an amine compound having 25 or less carbon atoms (hereinafter sometimes abbreviated as "amine compound"), a quaternary ammonium salt having 25 or less carbon atoms (hereinafter abbreviated as "quaternary ammonium salt"). Ammonia, an ammonium salt formed by reacting an amine compound having 25 or less carbon atoms with an acid (hereinafter sometimes abbreviated as “ammonium salt derived from amine compound”), and ammonia reacting with an acid. One or more selected from the group consisting of ammonium salts (hereinafter, may be abbreviated as “ammonium salt derived from ammonia”). That is, the nitrogen-containing compound to be blended may be only one kind or two or more kinds. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

(Amine compound, quaternary ammonium salt)
The amine compound has 1 to 25 carbon atoms, and may be any of primary amine, secondary amine and tertiary amine. The quaternary ammonium salt has 4 to 25 carbon atoms. The amine compound and the quaternary ammonium salt may be linear or cyclic. Further, the number of nitrogen atoms (for example, nitrogen atoms constituting the amino group (—NH ₂ ) of the primary amine) constituting the amine moiety or ammonium salt moiety may be one, or may be two or more.

Examples of the primary amine include monoalkylamine, monoarylamine, mono(heteroaryl)amine, and diamine in which one or more hydrogen atoms may be substituted with a substituent.

The alkyl group constituting the monoalkylamine may be linear, branched or cyclic, and examples thereof include the same ones as the alkyl group for R, which may be linear or branched having 1 to 19 carbon atoms. It is preferably a chain alkyl group or a cyclic alkyl group having 3 to 7 carbon atoms.
As the preferable monoalkylamine, specifically, n-butylamine, n-hexylamine, n-octylamine, n-dodecylamine, n-octadecylamine, sec-butylamine, tert-butylamine, 3-aminopentane, 3 Examples include -methylbutylamine, 2-heptylamine (2-aminoheptane), 2-aminooctane, 2-ethylhexylamine, and 1,2-dimethyl-n-propylamine.

Examples of the aryl group constituting the monoarylamine include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, and the like, and the carbon number is preferably 6 to 10.

The heteroaryl group constituting the mono(heteroaryl)amine has a hetero atom as an atom constituting the aromatic ring skeleton, and the hetero atom is a nitrogen atom, a sulfur atom, an oxygen atom or a boron atom. Can be illustrated. Further, the number of the heteroatoms constituting the aromatic ring skeleton is not particularly limited, and may be one or two or more. When the number is two or more, these hetero atoms may be the same or different from each other. That is, these heteroatoms may all be the same, all may be different, or only some may be different.
The heteroaryl group may be monocyclic or polycyclic, and the number of ring members (the number of atoms constituting the ring skeleton) is not particularly limited, but is preferably a 3- to 12-membered ring.

As the heteroaryl group, a monocyclic group having 1 to 4 nitrogen atoms includes a pyrrolyl group, a pyrrolinyl group, an imidazolyl group, a pyrazolyl group, a pyridyl group, a pyrimidyl group, a pyrazinyl group, a pyridazinyl group, a triazolyl group, and a tetrazolyl group. , A pyrrolidinyl group, an imidazolidinyl group, a piperidinyl group, a pyrazolidinyl group, and a piperazinyl group can be exemplified, and a 3- to 8-membered ring is preferable, and a 5- to 6-membered ring is more preferable.
Examples of the heteroaryl group having 1 oxygen atom include a furanyl group, preferably a 3- to 8-membered ring, and more preferably a 5- to 6-membered ring.
Examples of the heteroaryl group having a single sulfur atom include a thienyl group, preferably a 3- to 8-membered ring, and more preferably a 5- to 6-membered ring.
Examples of the heteroaryl group having 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms as a monocyclic group include an oxazolyl group, an isoxazolyl group, an oxadiazolyl group, and a morpholinyl group. It is preferably present, and more preferably a 5- or 6-membered ring.
Examples of the heteroaryl group having 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms include a thiazolyl group, a thiadiazolyl group, and a thiazolidinyl group, and a 3- to 8-membered ring. It is preferably a 5- or 6-membered ring.
The heteroaryl group, which is a polycyclic group having 1 to 5 nitrogen atoms, includes an indolyl group, an isoindolyl group, an indolizinyl group, a benzimidazolyl group, a quinolyl group, an isoquinolyl group, an indazolyl group, a benzotriazolyl group, and tetra. Examples thereof include a zolopyridyl group, a tetrazolopyridazinyl group, and a dihydrotriazolopyridazinyl group. A 7 to 12-membered ring is preferable, and a 9 to 10-membered ring is more preferable.
Examples of the polycyclic group having 1 to 3 sulfur atoms in the heteroaryl group include dithianaphthalenyl group and benzothiophenyl group, preferably 7 to 12 membered ring, and 9 to 10 membered ring. More preferably, it is a ring.
Examples of the polycyclic group having 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms in the heteroaryl group include a benzoxazolyl group and a benzooxadiazolyl group. Preferably, and more preferably a 9- to 10-membered ring.
Examples of the heterocyclic group having 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms include a benzothiazolyl group and a benzothiadiazolyl group, which are 7 to 12 membered rings. It is preferably a 9- to 10-membered ring.

The diamine only needs to have two amino groups, and the positional relationship between the two amino groups is not particularly limited. As the preferable diamine, in the monoalkylamine, monoarylamine or mono(heteroaryl)amine, one hydrogen atom other than the hydrogen atom constituting the amino group (—NH ₂ ) is substituted with an amino group. The thing can be illustrated.
The diamine preferably has 1 to 10 carbon atoms, and more preferable examples thereof include ethylenediamine, 1,3-diaminopropane and 1,4-diaminobutane.

Examples of the secondary amine include dialkylamine, diarylamine, di(heteroaryl)amine in which one or more hydrogen atoms may be substituted with a substituent.

The alkyl group constituting the dialkylamine is the same as the alkyl group constituting the monoalkylamine, and is a linear or branched alkyl group having 1 to 9 carbon atoms or 3 to 7 carbon atoms. It is preferably a cyclic alkyl group. Two alkyl groups in one molecule of dialkylamine may be the same or different from each other.
Specific examples of the preferable dialkylamine include N-methyl-n-hexylamine, diisobutylamine, and di(2-ethylhexyl)amine.

The aryl group constituting the diarylamine is the same as the aryl group constituting the monoarylamine, and preferably has 6 to 10 carbon atoms. The two aryl groups in one molecule of diarylamine may be the same or different from each other.

The heteroaryl group constituting the di(heteroaryl)amine is the same as the heteroaryl group constituting the mono(heteroaryl)amine and is preferably a 6- to 12-membered ring. Further, two heteroaryl groups in one molecule of di(heteroaryl)amine may be the same or different from each other.

Examples of the tertiary amine include trialkylamines in which one or more hydrogen atoms may be substituted with a substituent, dialkylmonoarylamines, and the like.

The alkyl group constituting the trialkylamine is the same as the alkyl group constituting the monoalkylamine, and is a linear or branched alkyl group having 1 to 19 carbon atoms, or 3 to 7 carbon atoms. It is preferably a cyclic alkyl group. Further, the three alkyl groups in one molecule of trialkylamine may be the same or different from each other. That is, all three alkyl groups may be the same, all may be different, and only one part may differ.
Specific examples of the preferable trialkylamine include N,N-dimethyl-n-octadecylamine and N,N-dimethylcyclohexylamine.

The alkyl group constituting the dialkylmonoarylamine is the same as the alkyl group constituting the monoalkylamine, and is a linear or branched alkyl group having 1 to 6 carbon atoms or 3 to 6 carbon atoms. The cyclic alkyl group of 7 is preferable. The two alkyl groups in one molecule of dialkylmonoarylamine may be the same or different from each other.
The aryl group constituting the dialkylmonoarylamine is the same as the aryl group constituting the monoarylamine, and preferably has 6 to 10 carbon atoms.

In the present invention, the quaternary ammonium salt may, for example, be a tetraalkylammonium halide in which one or more hydrogen atoms may be substituted with a substituent.
The alkyl group constituting the halogenated tetraalkylammonium is the same as the alkyl group constituting the monoalkylamine, and preferably has 1 to 19 carbon atoms. The four alkyl groups in one molecule of tetraalkylammonium halide may be the same or different from each other. That is, all four alkyl groups may be the same, all may be different, and only one part may differ.
Examples of the halogen constituting the tetraalkylammonium halide include fluorine, chlorine, bromine and iodine.
Specific examples of the preferred tetraalkylammonium halide include dodecyltrimethylammonium bromide.

Up to this point, the chain amine compound and the quaternary organic ammonium salt have been mainly described. However, in the amine compound and the quaternary ammonium salt, the nitrogen atom constituting the amine moiety or the ammonium salt moiety has a ring skeleton structure ( A heterocyclic compound which is a part of a heterocyclic skeleton structure) may be used. That is, the amine compound may be a cyclic amine and the quaternary ammonium salt may be a cyclic ammonium salt. At this time, the ring (ring containing a nitrogen atom constituting the amine moiety or ammonium salt moiety) structure may be either monocyclic or polycyclic, and the number of ring members (the number of atoms constituting the ring skeleton) is not particularly limited. Alternatively, it may be either an aliphatic ring or an aromatic ring.
If it is a cyclic amine, pyridine can be illustrated as a preferable example.

In the above-mentioned primary amine, secondary amine, tertiary amine and quaternary ammonium salt, “a hydrogen atom which may be substituted with a substituent” means a nitrogen atom constituting an amine moiety or an ammonium salt moiety. A hydrogen atom other than the hydrogen atom bonded to. The number of substituents at this time is not particularly limited, and may be one, two or more, and all of the hydrogen atoms may be substituted with substituents. When the number of substituents is plural, the plural substituents may be the same or different from each other. That is, the plurality of substituents may all be the same, may all be different, or only some may be different. Moreover, the position of the substituent is not particularly limited.

Examples of the substituent in the amine compound and quaternary ammonium salt, an alkyl group, an aryl group, a halogen atom, a cyano group, a nitro group, a hydroxyl group, trifluoromethyl group (-CF ₃₎ or the like can be exemplified. Here, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

When the alkyl group constituting the monoalkylamine has a substituent, the alkyl group has an aryl group as a substituent, and is a linear or branched alkyl group having 1 to 9 carbon atoms, or a substituent. Is preferably an alkyl group having 1 to 5 carbon atoms, and a cyclic alkyl group having 3 to 7 carbon atoms is preferable, and specific examples of the monoalkylamine having such a substituent include 2-phenylethylamine. , Benzylamine and 2,3-dimethylcyclohexylamine can be exemplified.
Further, in the aryl group and the alkyl group which are substituents, one or more hydrogen atoms may be further substituted with a halogen atom, and as a monoalkylamine having a substituent substituted with such a halogen atom, , 2-bromobenzylamine can be exemplified. Here, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

When the aryl group constituting the monoarylamine has a substituent, the aryl group is preferably an aryl group having a halogen atom as a substituent and having 6 to 10 carbon atoms, and the monoaryl having such a substituent. Specific examples of amines include bromophenylamine. Here, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

When the alkyl group constituting the dialkylamine has a substituent, the alkyl group is preferably a linear or branched alkyl group having 1 to 9 carbon atoms, which has a hydroxyl group or an aryl group as a substituent, Specific examples of the dialkylamine having such a substituent include diethanolamine and N-methylbenzylamine.

The amine compound is n-propylamine, n-butylamine, n-hexylamine, n-octylamine, n-dodecylamine, n-octadecylamine, sec-butylamine, tert-butylamine, 3-aminopentane, 3-methyl. Butylamine, 2-heptylamine, 2-aminooctane, 2-ethylhexylamine, 2-phenylethylamine, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, N-methyl-n-hexylamine, diisobutylamine, It is preferably N-methylbenzylamine, di(2-ethylhexyl)amine, 1,2-dimethyl-n-propylamine, N,N-dimethyl-n-octadecylamine or N,N-dimethylcyclohexylamine. ..
Among these amine compounds, 2-ethylhexylamine has excellent compatibility with the above-mentioned silver carboxylate and is particularly suitable for increasing the concentration of the silver ink composition, and particularly for reducing the surface roughness of metallic silver. It is mentioned as a suitable one.

(Ammonium compound-derived ammonium salt)
In the present invention, the ammonium salt derived from the amine compound is an ammonium salt formed by reacting the amine compound with an acid, and the acid may be an inorganic acid such as hydrochloric acid, sulfuric acid or nitric acid, or an organic acid such as acetic acid. However, the type of acid is not particularly limited.
Examples of the ammonium salt derived from the amine compound include, but are not limited to, n-propylamine hydrochloride, N-methyl-n-hexylamine hydrochloride, N,N-dimethyl-n-octadecylamine hydrochloride and the like. ..

(Ammonia-derived ammonium salt)
In the present invention, the ammonium salt derived from ammonia is an ammonium salt formed by the reaction of ammonia with an acid, and the same acid as the ammonium salt derived from the amine compound can be exemplified here.
Examples of the ammonium salt derived from ammonia include, but are not limited to, ammonium chloride and the like.

In the present invention, the amine compound, the quaternary ammonium salt, the amine compound-derived ammonium salt, and the ammonia-derived ammonium salt may be used alone or in combination of two or more. .. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.
As the nitrogen-containing compound, one selected from the group consisting of the amine compound, quaternary ammonium salt, amine compound-derived ammonium salt and ammonia-derived ammonium salt may be used alone, or You may use together 1 or more types. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

In the silver ink composition, the compounding amount of the nitrogen-containing compound is preferably 0.3 to 15 mol, and more preferably 0.3 to 5 mol, per 1 mol of the compounding amount of the metal silver forming material. preferable. By setting the blending amount of the nitrogen-containing compound in such a range, the stability of the silver ink composition is further improved, and the quality of the conductor (metal silver) is further improved. Furthermore, the conductor can be formed more stably without performing heat treatment at high temperature.

[Reducing agent]
It is preferable that the silver ink composition further contains a reducing agent in addition to the metal silver forming material. The reducing agent is preferably used in order to form metallic silver having a crystallite size of 15 nm or more. By adding a reducing agent, the silver ink composition becomes easier to form metallic silver, and for example, a conductor (metallic silver) having sufficient conductivity can be formed even by heat treatment at a low temperature.

The reducing agent is one or more reducing compounds selected from the group consisting of oxalic acid, hydrazine, and a compound represented by the following general formula (5) (hereinafter sometimes abbreviated as “compound (5)”). (Hereinafter, may be simply referred to as “reducing compound”).
H-C(=O)-R ²¹ ...(5)
(In the formula, R ²¹ is an alkyl group having 20 or less carbon atoms, an alkoxy group, an N,N-dialkylamino group, a hydroxyl group or an amino group.)

(Reducing compound)
The reducing compound, oxalic acid (HOOC-COOH), hydrazine _{(H 2} N-NH 2) and the compound represented by formula (5) (Compound (5)) one or more selected from the group consisting of Is. That is, the reducing compound to be blended may be only one kind or two or more kinds, and when two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

The alkyl group having 20 or less carbon atoms in R ²¹ has 1 to 20 carbon atoms, and may be linear, branched or cyclic, and is the same as the alkyl group in R in the general formula (1). The thing can be illustrated.

Examples of the alkoxy group having 20 or less carbon atoms in R ²¹ include a monovalent group having 1 to 20 carbon atoms and having the alkyl group in R ²¹ bonded to an oxygen atom.

The N,N-dialkylamino group having 20 or less carbon atoms in R ²¹ has 2 to 20 carbon atoms, and the two alkyl groups bonded to the nitrogen atom may be the same or different from each other. The alkyl groups each have 1 to 19 carbon atoms. However, the total number of carbon atoms of these two alkyl groups is 2 to 20.
The alkyl group bonded to the nitrogen atom may be linear, branched, or cyclic, and has the carbon number of 1 to 19, except for the alkyl in R of the general formula (1). The same thing as a group can be illustrated.

As the reducing compound, hydrazine may be a monohydrate (H ₂ N—NH ₂ ·H ₂ O).

As it preferred by the reducing compound, formic acid (H-C (= O) -OH); methyl formate (H-C (= O) -OCH 3), ethyl formate (H-C (= O) -OCH ₂ CH _3), butyl formate (H-C (= O) -O (CH 2) 3 formic ester of CH ₃₎ or the like; propanal _{(H-C (= O)} -CH 2 CH 3), butanal (H _{-C (= O) - (CH} 2) 2 CH 3), hexanal (H-C (= O) - (CH 2) 4 aldehyde CH ₃₎ or the like; dimethylformamide (H-C (= O) -NH 2 ), N, N- dimethylformamide (H-C (= O) -N (CH 3) 2) formamide such as (where "H-C (= O) -N (-) - " a group represented by And a compound having; oxalic acid.

In the silver ink composition, the compounding amount of the reducing agent is preferably 0.04 to 3.5 mol, and preferably 0.06 to 2.5 mol, per 1 mol of the metal silver forming material. Is more preferable. When the blending amount of the reducing agent is within such a range, the silver ink composition can more easily and more stably form a conductor (metallic silver).

[alcohol]
The silver ink composition may further contain alcohol in addition to the material for forming metallic silver.

The alcohol is preferably an acetylene alcohol represented by the following general formula (2) (hereinafter, may be abbreviated as “acetylene alcohol (2)”).

（式中、Ｒ’及びＲ’’は、それぞれ独立に炭素数１〜２０のアルキル基、又は１個以上の水素原子が置換基で置換されていてもよいフェニル基である。）

(In the formula, R′ and R″ are each independently a C 1-20 alkyl group, or a phenyl group in which one or more hydrogen atoms may be substituted with a substituent.)

(Acetylene alcohol (2))
The acetylene alcohol (2) is represented by the general formula (2).
In the formula, R′ and R″ are each independently an alkyl group having 1 to 20 carbon atoms, or a phenyl group in which one or more hydrogen atoms may be substituted with a substituent.
The alkyl group having 1 to 20 carbon atoms in R′ and R″ may be linear, branched or cyclic, and when cyclic, may be monocyclic or polycyclic. Examples of the alkyl group for R′ and R″ are the same as those for the alkyl group for R.

Examples of the substituent which may be substituted for the hydrogen atom of the phenyl group in R′ and R″ include a saturated or unsaturated monovalent aliphatic hydrocarbon group having 1 to 16 carbon atoms, and the above aliphatic hydrocarbon. A monovalent group in which a hydrogen group is bonded to an oxygen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, a cyano group, a phenoxy group and the like can be exemplified, and the hydrogen atom of the phenyl group in R may be substituted. It is the same as the above-mentioned substituent. The number and position of the substituents are not particularly limited, and when the number of the substituents is plural, these plural substituents may be the same or different from each other.

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.

Examples of preferable acetylene alcohol (2) include 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-butyn-3-ol, and 3-methyl-1-pentyn-3-ol.

When the acetylene alcohol (2) is used, in the silver ink composition, the compounding amount of the acetylene alcohol (2) is preferably 0.03 to 0.7 mol per 1 mol of the compounding amount of the metal silver forming material. , 0.05 to 0.3 mol is more preferable. When the blending amount of the acetylene alcohol (2) is in such a range, the stability of the silver ink composition is further improved.

The alcohols may be used alone or in combination of two or more. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

[Other ingredients]
The silver ink composition may contain other components other than the metallic silver forming material, the nitrogen-containing compound, the reducing agent and the alcohol.
The above-mentioned other components in the silver ink composition can be arbitrarily selected according to the purpose and are not particularly limited. Preferred examples thereof include solvents other than alcohol.

The solvent can be arbitrarily selected according to the type and amount of the compounding ingredients. As a preferable solvent, a liquid alkane under normal temperature and pressure conditions can be exemplified, and the alkane may be linear, branched or cyclic, and preferably has 15 or less carbon atoms, and more preferably Examples thereof include pentane, hexane, cyclohexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane and the like.

The other components in the silver ink composition may be used alone or in combination of two or more. When two or more kinds are used in combination, the combination and the ratio can be arbitrarily adjusted.

The blending amount of the other component in the silver ink composition may be appropriately selected according to the type of the other component.
For example, when the other component is a solvent other than alcohol, the blending amount of the solvent may be selected according to the purpose such as the viscosity of the silver ink composition, but is usually blended in the silver ink composition. The ratio of the amount of the solvent blended with respect to the total amount of the components is preferably 25% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less.
When the other component is a component other than the solvent, the ratio of the blending amount of the other component to the total amount of the blending component in the silver ink composition is preferably 10% by mass or less, and 5% by mass. % Or less is more preferable.
The ratio of the blending amount of the other components to the total amount of the blending components is 0 mass, that is, the silver ink composition sufficiently exerts its effect without blending the other components.

The silver ink composition may have all the components mixed therein, or may have a state in which some or all of the components are not dissolved but dispersed, but it is preferable that all the components are dissolved. It is preferable that the undissolved components are uniformly dispersed.

[Method for producing silver ink composition]
The silver ink composition can be obtained by blending the metallic silver forming material and components other than the metallic silver forming material. After blending the respective components, the obtained product may be used as it is as a silver ink composition, or the product obtained by subsequently performing a known refining operation may be used as a silver ink composition. In the present invention, particularly when β-ketocarboxylate silver (1) is used as a material for forming the metallic silver, impurities that inhibit conductivity are not generated at the time of blending each of the above components, or Since the amount of impurities produced can be suppressed to an extremely small amount, a conductor (metallic silver) having sufficient conductivity can be obtained even if a silver ink composition that has not been subjected to a refining operation is used.

At the time of blending each component, all components may be added and then mixed, or some components may be sequentially added and mixed, or all components may be sequentially added and mixed. Good. However, in the present invention, it is preferable to add the reducing agent by dropping, and further suppressing the fluctuation of the dropping rate tends to further reduce the surface roughness of the metallic silver.
The mixing method is not particularly limited, a method of mixing by rotating a stirrer or a stirring blade, etc.; a method of mixing using a mixer, a triple roll, a kneader or a bead mill, etc.; a method of adding ultrasonic waves and the like, It may be appropriately selected from known methods.
When the undissolved components are uniformly dispersed in the silver ink composition, it is preferable to apply the method of dispersing using, for example, the above-mentioned three-roll, kneader or bead mill.

The temperature at the time of compounding is not particularly limited as long as each compounding component does not deteriorate, but is preferably -5 to 60°C. Then, the temperature at the time of compounding may be appropriately adjusted according to the type and amount of the compounding components so that the mixture obtained by compounding has a viscosity that facilitates stirring.
The compounding time is not particularly limited as long as each compounding component does not deteriorate, but is preferably 10 minutes to 36 hours.

[carbon dioxide]
The silver ink composition may further be supplied with carbon dioxide. Such a silver ink composition has a high viscosity, and is suitable for printing methods that require thick ink, such as flexographic printing methods, screen printing methods, gravure printing methods, gravure offset printing methods, and pad printing methods. Suitable for application.

Carbon dioxide may be supplied at any time during the production of the silver ink composition.
And, in the present invention, for example, carbon dioxide is supplied to a first mixture in which the material for forming metallic silver and a nitrogen-containing compound are blended to obtain a second mixture, and the second mixture is added if necessary. It is preferable to add the reducing agent to the mixture to produce a silver ink composition. When the alcohol or other component is blended, these can be blended at the time of producing either or both of the first mixture and the second mixture, and can be arbitrarily selected according to the purpose.

The first mixture can be produced by the same method as the above silver ink composition except that the components are different.

The first mixture may have all of the ingredients mixed, or some ingredients may be in a dispersed state without being dissolved, but it is preferable that all the ingredients are dissolved. It is preferable that the components that are not included are uniformly dispersed.

The compounding temperature at the time of producing the first mixture is not particularly limited as long as each compounding component does not deteriorate, but it is preferably -5 to 30°C. The blending time may be appropriately adjusted depending on the type of blended components and the temperature during blending, but is preferably 0.5 to 12 hours, for example.

Carbon dioxide (CO ₂ ) supplied to the first mixture may be in a gaseous state or a solid state (dry ice), or may be in a gaseous state or a solid state. It is speculated that the supply of carbon dioxide causes the carbon dioxide to dissolve in the first mixture and act on the components in the first mixture, thereby increasing the viscosity of the obtained second mixture.

The carbon dioxide gas may be supplied by various known methods of blowing gas into the liquid, and a suitable supply method may be appropriately selected. For example, a method can be exemplified in which one end of the pipe is immersed in the first mixture, the other end is connected to a carbon dioxide gas supply source, and carbon dioxide gas is supplied to the first mixture through this pipe. At this time, the carbon dioxide gas may be directly supplied from the end of the pipe, but for example, a porous material or the like is provided with a large number of voids that can serve as gas flow passages to diffuse the introduced gas. A gas diffusion member capable of discharging as minute bubbles may be connected to the end portion of the pipe, and carbon dioxide gas may be supplied via this gas diffusion member. Further, carbon dioxide gas may be supplied while stirring the first mixture in the same manner as in the production of the first mixture. By doing so, carbon dioxide can be efficiently supplied.

The supply amount of carbon dioxide gas may be appropriately adjusted according to the amount of the first mixture as the supply destination and the viscosity of the intended silver ink composition or the second mixture, and is not particularly limited. For example, in order to obtain about 100 to 1000 g of a silver ink composition having a viscosity of 5 Pa·s or more at 20 to 25° C., it is preferable to supply 100 L or more, and more preferably 200 L or more of carbon dioxide gas. Although the viscosity of the silver ink composition at 20 to 25°C has been described here, the temperature at the time of using the silver ink composition is not limited to 20 to 25°C and can be arbitrarily selected. Further, in the present specification, “viscosity” means the value measured using an ultrasonic vibration viscometer, unless otherwise specified.

The flow rate of carbon dioxide gas may be appropriately adjusted in consideration of the required supply amount of carbon dioxide gas, but is preferably 0.5 mL/min or more per 1 g of the first mixture, and 1 mL/min or more Is more preferable. Although the upper limit of the flow rate is not particularly limited, it is preferably 40 mL/min per 1 g of the mixture in consideration of handleability and the like.
Then, the supply time of the carbon dioxide gas may be appropriately adjusted in consideration of the required supply amount and flow rate of the carbon dioxide gas.

The temperature of the first mixture at the time of supplying carbon dioxide gas is preferably 5 to 70°C, more preferably 7 to 60°C, and particularly preferably 10 to 50°C. When the temperature is equal to or higher than the lower limit value, carbon dioxide can be more efficiently supplied, and when the temperature is equal to or lower than the upper limit value, a silver ink composition having less impurities and better quality can be obtained.

The flow rate and supply time of carbon dioxide gas, and the temperature at the time of carbon dioxide gas supply may be adjusted to appropriate ranges while mutually considering the respective values. For example, even if the temperature is set to be low, the flow rate of carbon dioxide gas may be set to be high, the supply time of carbon dioxide gas may be set to be long, or both of them may be performed to efficiently perform the oxidation. Can supply carbon. In addition, even if the flow rate of carbon dioxide gas is set low, by increasing the temperature or setting the supply time of carbon dioxide gas for a long time, or by performing both of them, the carbon dioxide can be efficiently supplied. Can be supplied. That is, the flow rate of carbon dioxide gas, numerical values in the above numerical range exemplified as the temperature at the time of carbon dioxide gas supply are flexibly combined in consideration of the supply time of carbon dioxide gas, so that a good quality silver ink is obtained. The composition is efficiently obtained.

The carbon dioxide gas is preferably supplied while stirring the first mixture. By doing so, the supplied carbon dioxide gas is more uniformly diffused in the first mixture, and the carbon dioxide can be supplied more efficiently.
The stirring method at this time may be the same as the mixing method in the production of the above silver ink composition without using carbon dioxide.

The supply of dry ice (solid carbon dioxide) may be performed by adding dry ice to the first mixture. The dry ice may be added all at once, or may be added stepwise (continuously with a time zone in which no addition is performed).
The amount of dry ice used may be adjusted in consideration of the above-mentioned supply amount of carbon dioxide gas.
It is preferable to stir the first mixture during and after the addition of dry ice, and for example, it is preferable to stir in the same manner as in the production of the above silver ink composition without using carbon dioxide. By doing so, carbon dioxide can be efficiently supplied.
The temperature at the time of stirring may be the same as that at the time of supplying carbon dioxide gas. In addition, the stirring time may be appropriately adjusted according to the stirring temperature.

The viscosity of the second mixture may be appropriately adjusted according to the purpose, such as the method of handling the silver ink composition or the second mixture, and is not particularly limited. For example, when the silver ink composition is applied to a printing method using a high-viscosity ink such as a screen printing method or a flexographic printing method, the viscosity of the second mixture at 20 to 25° C. is 3 Pa·s or more. It is preferable. Although the viscosity of the second mixture at 20 to 25°C has been described here, the temperature when the second mixture is used is not limited to 20 to 25°C and can be arbitrarily selected.

If necessary, one or more kinds selected from the group consisting of the reducing agent, alcohol, and other components may be further added to the second mixture to prepare a silver ink composition.
The silver ink composition at this time can be produced by the same method as the above-described silver ink composition using no carbon dioxide except that the components are different. In the obtained silver ink composition, all the components may be dissolved, or some components may be in a dispersed state without being dissolved, but all the components are dissolved. It is preferable that the undissolved components are uniformly dispersed.

The temperature at the time of blending the reducing agent is not particularly limited as long as each blending component does not deteriorate, but is preferably -5 to 60°C. Then, the temperature at the time of compounding may be appropriately adjusted according to the type and amount of the compounding components so that the mixture obtained by compounding has a viscosity that facilitates stirring.
The compounding time may be appropriately adjusted according to the type of compounding ingredients and the temperature at the time of compounding, but is preferably 0.5 to 12 hours, for example.

As described above, the other components may be added during the production of either the first mixture or the second mixture, or during the production of both. That is, in the process of producing a silver ink composition via the first mixture and the second mixture, the ratio of the blending amount of the other component to the total amount of the blending components other than carbon dioxide ([other component (mass)] /[Metallic silver forming material, nitrogen-containing compound, reducing agent, alcohol, and other components (mass)]×100) is 25% by mass or less when the other components are solvents other than alcohol Is preferred, 20% by mass or less is more preferred, and 15% by mass or less is particularly preferred. On the other hand, when the other component is a component other than the solvent, the content ratio is preferably 10% by mass or less, and more preferably 5% by mass or less. The silver ink composition sufficiently exerts its effect even if the ratio of the blended amount is 0 mass, that is, without blending other components.

The silver ink composition supplied with carbon dioxide has a viscosity at 20 to 25° C. when the silver ink composition is applied to a printing method using a high-viscosity ink such as a screen printing method or a flexographic printing method. Is preferably 1 Pa·s or more.

For example, when the reducing agent is blended, the resulting blend (silver ink composition) is likely to generate heat. When the temperature at the time of compounding the reducing agent is high, this compound is in a state similar to that at the time of the heat treatment of the silver ink composition described later, and therefore, due to the action of promoting the decomposition of the metallic silver forming material by the reducing agent. It is speculated that the formation of metallic silver may start in at least a part of the material for forming metallic silver. In such a silver ink composition containing metallic silver, a conductor may be formed by performing post-treatment under a milder condition than that of a silver ink composition containing no metallic silver at the time of forming a conductor. Even when the amount of the reducing agent blended is sufficiently large, the conductor may be formed by similarly performing the post-treatment under mild conditions. In this way, by adopting the conditions that promote the decomposition of the material for forming metallic silver, the post-treatment may be a heat treatment at a lower temperature, or a dry treatment at room temperature may be performed without heat treatment. Can be formed. Further, such a silver ink composition containing metallic silver can be handled in the same manner as a silver ink composition containing no metallic silver, and is not particularly inferior in handleability.

The viscosity of the second mixture in the present invention is higher than usual due to the supply of carbon dioxide as described above. On the other hand, at the time of blending the reducing agent into the second mixture, depending on the type of the second mixture or the reducing agent, the formation of metallic silver is started in at least a part of the material for forming metallic silver as described above, Metallic silver may precipitate. Here, when the viscosity of the second mixture is high, the agglomeration of the deposited metal silver is suppressed, and the dispersibility of the metal silver in the obtained silver ink composition is improved. A conductor obtained by forming metallic silver by the method described below using such a silver ink composition has a low viscosity, that is, a reducing agent is added to a mixture to which carbon dioxide is not supplied. Further, the conductivity is higher (volume resistivity is lower) and the surface roughness is smaller than that of the conductor using the silver ink composition, and more preferable properties are obtained.

Further, in the present invention, it is also preferable to supply carbon dioxide to a mixture prepared by mixing the material for forming metallic silver, alcohol and a nitrogen-containing compound to produce a silver ink composition. In this case, as the method of supplying carbon dioxide, the same method as described above can be adopted.

When the silver ink composition is dried, it may be carried out by a known method, for example, it may be carried out under any conditions of normal pressure, reduced pressure and blown air, either under air or under an inert gas atmosphere. May be done. The drying temperature is also not particularly limited, and may be either heat drying or room temperature drying. As a preferable drying method when heat treatment is unnecessary, a method of drying in the air at 18 to 30°C can be exemplified.

When the silver ink composition is heated (baked), the conditions thereof may be appropriately adjusted according to the type of blending components of the silver ink composition. Usually, the heating temperature is preferably 60 to 370°C, more preferably 70 to 280°C. The heating time may be adjusted according to the heating temperature, but is usually preferably 1 minute to 24 hours, and more preferably 1 minute to 12 hours. Among the metal silver forming materials, the silver carboxylate, particularly the β-ketocarboxylate silver (1) is different from the metal silver forming material such as silver oxide by using a reducing agent or the like known in the art. Even without it, it decomposes at low temperatures. Then, reflecting such a decomposition temperature, the silver ink composition can form metallic silver at a much lower temperature than the conventional one, as described above.

As will be described later, when the silver ink composition is attached to a substrate having low heat resistance and heated (baked), the heating temperature is preferably lower than 130°C, more preferably 125°C or lower. It is preferably 120° C. or lower, and particularly preferably 120° C. or lower.

The method of heat-treating the silver ink composition is not particularly limited, and for example, heating with an electric furnace, heating with a heat-sensitive thermal head, heating with far-infrared irradiation, heating with blowing of a high-temperature gas, or the like can be performed. Further, the heat treatment of the silver ink composition may be performed in the air, in an inert gas atmosphere, or under humidified conditions. Then, it may be performed under normal pressure, reduced pressure, or increased pressure.

In the present specification, "humidification" means artificially increasing the humidity, unless otherwise specified, and preferably the relative humidity is 5% or more. At the time of heat treatment, since the treatment temperature is high and the humidity in the treatment environment is extremely low, it can be said that the relative humidity of 5% is artificially increased.

When the heat treatment of the silver ink composition is performed under humidified conditions, the relative humidity is preferably 10% or more, more preferably 30% or more, further preferably 50% or more, and 70%. It is particularly preferable that it is not less than 90% and may be 100%. The heat treatment under humidified conditions may be performed by spraying high-pressure steam heated to 100° C. or higher. By performing the heat treatment under the humidified condition as described above, it is possible to form higher purity metallic silver in a short time.

The heat treatment of the silver ink composition may be performed in two steps. For example, in the first stage heat treatment, not the formation of metallic silver but the drying of the silver ink composition is mainly performed, and in the second stage heat treatment, the formation of metallic silver is completed.
In the heat treatment of the first step, the heating temperature may be appropriately adjusted according to the type of the blended components of the silver ink composition, but is preferably 60 to 110°C, and more preferably 70 to 90°C. preferable. The heating time may be adjusted according to the heating temperature, but is usually preferably 5 seconds to 12 hours, more preferably 30 seconds to 2 hours.
In the second stage heat treatment, the heating temperature may be appropriately adjusted according to the type of the blended components of the silver ink composition so that the metallic silver is favorably formed, but the heating temperature is 60 to 280°C. It is preferably 70 to 260°C and more preferably. The heating time may be adjusted according to the heating temperature, but is usually preferably 1 minute to 12 hours, and more preferably 1 minute to 10 hours.
As will be described later, when the silver ink composition is adhered to a substrate having low heat resistance and subjected to heating (baking) treatment, the heating temperature in the first and second heat treatments is less than 130°C. It is preferably 125° C. or lower, more preferably 120° C. or lower.

Although the heat treatment of the silver ink composition described so far is performed in the gas phase, when the heat treatment of the silver ink composition is performed in two steps, the second heat treatment is performed in the gas phase. It may be carried out in the liquid phase instead of the inside. The silver ink composition, which has been completely or partially dried after the first-stage heat treatment, can be subjected to the second-stage heat treatment without losing its shape by bringing it into contact with a heated liquid. The heat treatment of the silver ink composition in the second liquid phase after the first heat treatment is preferably performed by immersing the silver ink composition in the heated liquid. The heating temperature and the heating time in the heat treatment in the liquid phase are the same as the heating temperature and the heating time in the second-step heat treatment described above.
The above-mentioned heated liquid is preferably hot water (heated water), and the second-step heat treatment is to immerse the silver ink composition subjected to the first-step heat treatment in hot water, that is, by boiling. It is preferable to carry out.
When the second stage heat treatment is performed in the liquid phase, the metallic silver formed by this heat treatment may be further dried.

When the second heat treatment of the silver ink composition is performed in the liquid phase, the first heat treatment of the silver ink composition is preferably performed under non-humidified conditions.
In the present specification, "non-humidifying" means that the above-mentioned "humidifying" is not performed, that is, the humidity is not artificially increased, and the relative humidity is preferably less than 5%. ..

When the heat treatment under humidified conditions is adopted, the heat treatment of the silver ink composition is performed in the first-stage heat treatment under non-humidified conditions without forming metallic silver as described above. It is particularly preferable to carry out a two-step method in which the drying is mainly performed, and in the second-stage heat treatment, the formation of metallic silver is performed to the end as described above under humidified conditions.

When the second-step heat treatment is performed under humidified conditions, the heating temperature during the first-step non-humidified condition is preferably 60 to 110°C, and preferably 70 to 90°C. More preferable. The heating time is preferably 5 seconds to 1 hour, more preferably 30 seconds to 30 minutes, and particularly preferably 30 seconds to 10 minutes.
The heating temperature during the heat treatment under the second stage humidifying condition, which is performed after the heat treatment under the first stage non-humidifying condition, is preferably 60 to 140°C, and 70 to 130°C. Is more preferable. The heating time is preferably 1 minute to 2 hours, more preferably 1 minute to 1 hour, and particularly preferably 1 minute to 30 minutes.
As described below, when the silver ink composition is adhered to a substrate having low heat resistance and subjected to heat treatment (baking), heat treatment under non-humidifying conditions in the first step and humidifying conditions in the second step are performed. The heating temperature in the above heat treatment is preferably less than 130°C, more preferably 125°C or lower, and particularly preferably 120°C or lower.

As described above, as a preferable method for producing the metallic silver, for example, one having a step of forming the metallic silver by using silver β-ketocarboxylate (1) can be mentioned, and as a preferable producing method among them, Is, for example, after heat-treating a silver ink composition containing silver β-ketocarboxylate (1) in a non-humidifying condition in the step of forming the metallic silver, and further under a humidifying condition or by heating. An example is one in which the metallic silver is formed by bringing the liquid into contact with the liquid and performing heat treatment.

<< laminated body >>
The layered product of the present invention has a layer comprising the above-described metallic silver of the present invention (hereinafter, may be abbreviated as “silver layer”) on a substrate.
The metallic silver can be formed by subjecting the silver ink composition for forming the same to a post-treatment such as a drying treatment or a heating (baking) treatment at a low temperature of less than 130° C., and thus the heat resistance of the base material is high. The silver layer can be formed by using a material having a low viscosity, and a wide range of materials can be used. Further, the silver layer of the laminate has the volume resistivity of 8 μΩ·cm or less because it is made of the metallic silver, and has sufficiently high conductivity.

FIG. 1 is a sectional view schematically showing an example of the laminated body of the present invention.
The laminated body 1 shown here is formed by laminating a silver layer 12 on a surface (one main surface) 11 a of a base material 11.

<Substrate>
The substrate 11 is not particularly limited as long as it can use the composition for forming the above-described metallic silver.
Specifically as the material of the base material 11, polyethylene (PE); polypropylene (PP); polyvinyl chloride (PVC); polyvinylidene chloride (PVDC); polymethylpentene (PMP); polycycloolefin; polystyrene (PS) Polyvinyl acetate (PVAc); Acrylic resin such as polymethylmethacrylate (PMMA); AS resin; ABS resin; Polyamide (PA) such as nylon 6,6 and nylon 6; Polyimide; Polyamide imide (PAI); Polyacetal ( POM); polyethylene terephthalate (PET); polybutylene terephthalate (PBT); polytrimethylene terephthalate (PTT); polyethylene naphthalate (PEN); polybutylene naphthalate (PBN); polyphenylene sulfide (PPS); polysulfone (PSF) Polyether sulfone (PES); Polyether ketone (PEK); Polyether ether ketone (PEEK); Polycarbonate (PC); Polyurethane; Polyphenylene ether (PPE); Modified polyphenylene ether (m-PPE); Polyarylate; Epoxy resin Examples thereof include melamine resins, phenol resins, and synthetic resins such as urea resins.
In addition to the above, the material of the base material 11 may be glass, ceramics such as silicon, or paper.
Further, the substrate 11 may be a combination of two or more kinds of materials such as glass epoxy resin and polymer alloy.

In the present invention, as the base material 11 having low heat resistance, a base material 11 having a deflection temperature under load of 120° C. or less when the deflection amount is 0.25 mm at a bending stress of 1.8 MPa specified by ASTM D648 is used. It can be illustrated.
Examples of preferable materials for the base material 11 include polyethylene, polypropylene homopolymer, ABS resin, polyacetal copolymer, polyethylene terephthalate, nylon 6,6, nylon 6, polycarbonate/ABS resin alloy and the like.

The substrate 11 can be selected in any shape according to the purpose, and for example, it is preferably in the form of a film or a sheet, and the thickness thereof is preferably 0.5 to 5000 μm, and 0.5 to 2500 μm. Is more preferable. When the thickness of the base material 11 is equal to or more than the lower limit value, the structure of the silver layer can be held more stably, and when the thickness of the base material 11 is equal to or less than the upper limit value, handling during silver layer formation The property becomes better.

The base material 11 may be composed of a single layer or plural layers of two or more layers. When the base material 11 is composed of a plurality of layers, the plurality of layers may be the same or different from each other. That is, all layers may be the same, all layers may be different, or only some layers may be different. When the plurality of layers are different from each other, the combination of the plurality of layers is not particularly limited. Here, the plurality of layers being different from each other means that at least one of the material and the thickness of each layer is different from each other.
When the base material 11 is composed of a plurality of layers, the total thickness of each layer may be the preferable thickness of the base material 11.

<Silver layer>
The silver layer 12 is made of the above-described metallic silver of the present invention.
The shape of the silver layer 12 when the laminate 1 is viewed in plan so that one main surface (front surface) 11a of the base material 11 is looked down from above can be arbitrarily set according to the purpose. The silver layer 12 may be provided on the entire surface of the substrate 11a, or the silver layer 12 may be provided on only a part of the surface 11a of the base material 11. In this case, the silver layer 12 is patterned. May be.
The patterned silver layer 12 is useful as, for example, a wiring.

Although the thickness of the silver layer 12 can be arbitrarily set according to the purpose, it is preferably 0.01 to 5 μm, and more preferably 0.05 to 3 μm. When the thickness of the silver layer 12 is equal to or more than the lower limit value, the conductivity can be further improved, and the structure of the silver layer 12 can be more stably maintained. Moreover, when the thickness of the silver layer 12 is equal to or less than the upper limit value, the laminated body 1 can be made thinner.

The silver layer 12 may be composed of a single layer or plural layers of two or more layers. When the silver layer 12 is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and can be configured similarly to the case of the base material 11. For example, in the silver layer 12 including a plurality of layers, the total thickness of each layer may be the preferable thickness of the silver layer 12 described above.

The silver layer 12 has excellent conductivity, and its volume resistivity is 8 μΩ·cm or less as described above.

The layered product of the present invention is not limited to that shown in FIG. 1, and may have other configurations added or a part of the configurations appropriately changed within a range that does not impair the effects of the present invention. For example, a layer other than the silver layer 12 may be provided on the base material 11, and as the other layer, a receiving layer (not shown) provided between the base material 11 and the silver layer 12, And an overcoat layer (not shown) that covers the silver layer 12 and the like. The receiving layer improves the adhesion between the silver layer and the base material.
In addition, here, as the laminated body 1, one in which the silver layer 12 is provided on one main surface (front surface) 11a of the base material 11 is shown, but the laminated body of the present invention is the other main surface of the base material 11. Similarly, the surface (back surface) 11b may be provided with the silver layer 12 (on both main surfaces of the base material 11).

<<Manufacturing Method of Laminated Body>>
The laminate of the present invention can be manufactured by, for example, a manufacturing method including a step of forming a silver layer on a base material (hereinafter sometimes abbreviated as “silver layer forming step”).

<Silver layer forming step>
In the silver layer forming step, a silver layer is formed on the surface of the base material (in FIG. 1, the surface (main surface 11a) of the base material 11).

For the silver layer, the silver ink composition for forming the above-described metallic silver is adhered to a desired portion on the surface (main surface) of the substrate, and a solidification treatment such as a drying treatment or a heating (baking) treatment is appropriately performed. It can be formed by selecting it. The heat treatment may be combined with the drying treatment.

The silver ink composition can be attached to the substrate by a known method such as a printing method, a coating method, or a dipping method.
Examples of the printing method include screen printing, flexographic printing, offset printing, dip printing, inkjet printing, dispenser printing, jet dispenser printing, gravure printing, gravure offset printing, pad printing. The method etc. can be illustrated.
As the coating method, a spin coater, an air knife coater, a curtain coater, a die coater, a blade coater, a roll coater, a gate roll coater, a bar coater, a rod coater, a gravure coater, or any other coater, or a wire bar is used. It can be illustrated.

In the silver layer forming step, the thickness of the silver layer can be adjusted by adjusting the amount of the silver ink composition deposited on the substrate, or the blending amount of the metal silver forming material in the silver ink composition. ..

In the silver layer forming step, the substrate may be heat-treated (annealed) before the silver ink composition is attached. By heat-treating the base material, for example, when the silver ink composition is heated (baked), shrinkage of the base material is suppressed and dimensional stability is improved.
The conditions for heat treatment of the base material before applying the silver ink composition may be appropriately adjusted depending on the type of the base material, and are not particularly limited, but heat treatment at 60 to 200° C. for 10 to 60 minutes. Is preferable, and for example, the conditions of the heating (baking) treatment of the silver ink composition in the silver layer forming step may be the same.

Further, in the present invention, the surface of the base material may be plasma-treated before the silver ink composition is attached. Bleeding of the silver ink composition may be suppressed by plasma-treating the base material.
The plasma treatment may be performed by a known method. For example, in the case of atmospheric pressure plasma treatment, the plasma treatment can be performed under conditions of a voltage of 290 to 300 W and an air velocity of 1.0 to 5.0 m/min.

Except for these points, the silver layer can be formed by the same method as the method for producing metallic silver described above.

When the laminate of the present invention in which a layer other than the silver layer is provided on the substrate, the step of forming the other layer at a predetermined timing is appropriately added to the above production method. You can do it.
For example, in the case of producing a laminate having a receptive layer between a base material and a silver layer, the receptive layer is formed on the surface of the base material (receptive layer) before the silver layer is formed on the base material. Layer forming step), a silver layer may be formed on this receiving layer (silver layer forming step). The receptive layer is prepared by preparing a composition (composition for the receptive layer) in which components such as various resins for forming the receptive layer are mixed, and adhering the composition onto a substrate, for example, drying treatment or heat treatment. It can be formed by performing an operation for forming a receiving layer such as. The receiving layer composition can be deposited on the substrate in the same manner as for the silver ink composition.

<< Electronic equipment, transparent conductive film >>
The laminate is suitable for forming various electronic devices, transparent conductive films, and the like.
For example, an electronic device can be configured to include the base material as a housing (exterior material) using the laminate, and the base material in the laminate constitutes at least a part of the enclosure (exterior material). Except for the points, the configuration can be the same as that of a known electronic device. For example, by using a flat or curved portion of an exterior material in a communication device such as a mobile phone as the base material, forming a thin wire made of the metallic silver on the exterior material (base material), and forming the thin wire as a circuit, The laminate can be used as a circuit board. Then, for example, a mobile phone can be configured by combining a voice input unit, a voice output unit, an operation switch, a display unit, and the like in addition to the laminated body. Further, by using a patterned silver layer as an antenna, the laminated body can be used as an antenna structure, and the configuration is the same as that of a known data transmitter/receiver except that the antenna structure is used. As a result, a new data receiver/transmitter can be obtained. For example, a non-contact data transmitter/receiver can be configured by providing an IC chip electrically connected to a silver layer on a base material in the above laminated body to form an antenna portion.

In addition, the transparent conductive film can be configured by using the above-mentioned laminated body so as to have a silver layer as an ultrafine wiring or an ultrathin wiring, and a known transparent layer except that the silver layer is provided as an ultrafine wiring or an ultrathin wiring. It can have the same structure as the conductive film. For example, a touch panel or an optical display can be formed by combining a transparent base material or the like in addition to the laminate.
The line width of the ultrafine wiring is preferably 1 to 20 μm, more preferably 1.3 to 15 μm, and particularly preferably 1.5 to 13 μm.
In addition, the cross-sectional shape of the ultrafine wiring is preferably a semi-elliptical shape in which an approximately half region of the ellipse in the minor axis direction is cut out.
On the other hand, the thickness of the ultrathin wiring is preferably 5 nm to 10 μm, more preferably 7 nm to 5 μm, and particularly preferably 10 nm to 1 μm.
The cross-sectional shape of the ultra-thin wiring is the same as the cross-sectional shape of the ultra-fine wiring.
In the transparent conductive film, the silver layer preferably fills at least one of such line width and thickness. If the silver layer has such a line width or thickness, it is difficult to visually recognize its presence, and therefore it is preferable as a transparent conductive film.

Further, in the laminate, the silver layer can be formed at a low temperature, and a wide range of materials such as the base material can be selected, so that the degree of freedom in design is dramatically improved, and electronic devices, transparent conductive films, etc. Can be a more rational structure.
The above electronic devices, transparent conductive films, and the like can maintain high performance for a long period of time.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples described below.

[Example 1]
<Manufacture of laminated body>
(Production of silver ink composition)
2-Methylacetoacetic acid silver was added to 2-ethylhexylamine (0.4 times the molar amount of silver 2-methylacetoacetate described below) in a beaker so that the liquid temperature was 50° C. or lower, and a mechanical stirrer was used. A liquid was obtained by stirring for 15 minutes. Formic acid (0.7 times the molar amount of silver 2-methylacetoacetate) was added dropwise to this liquid substance using a syringe pump so that the temperature of the reaction liquid was 50° C. or lower over 30 minutes. After the dropwise addition of formic acid, the reaction solution was stirred at 25° C. for another hour to obtain a silver ink composition. Table 1 shows the types and mixing ratios of the respective components. In Table 1, the term "nitrogen-containing compound (molar ratio)" means the compounding amount (moles) of the nitrogen-containing compound per 1 mol of the metal silver forming material ([moles of nitrogen-containing compound]/[metal]. Mol number of silver forming material]). Similarly, for the “reducing agent (molar ratio)”, the compounding amount (moles) of the reducing agent per 1 mol of the compounding material of metallic silver ([moles of reducing agent]/[moles of forming material of metallic silver] Number]). "Other components (mass %)" means the ratio of the blending amount (mass) of the other components to the total amount (mass) of the blending components of the silver ink composition ([blending amount of other components (mass)]/[ It means the total amount (mass) of the blended components of the silver ink composition]×100). In Table 1, "-" in the column of blended components means that the components have not been blended. These are the same in the following tables.

(Manufacture of laminated body)
The silver ink composition obtained above was applied onto one main surface (front surface) of a substrate (thickness 2 mm) made of a polycarbonate/ABS resin alloy by spin coating. Spin coating was performed under conditions of 7500 rpm and 30 seconds. The base material has a deflection temperature under load of 120° C. or less when the deflection amount is 0.25 mm at a bending stress of 1.8 MPa specified by ASTM D648.
Then, the coated base material is dried at 80° C. for 1 minute by blowing hot air (air velocity: 15 m/sec), and the base material is placed in a steam atmosphere at 80° C. and a relative humidity of 100% for 2 minutes. By heating (baking) by heating, a silver layer having a size of 30 mm×30 mm and a thickness of 1 to 2 μm was formed on the base material to obtain a laminate. Table 2 shows the conditions for the heat treatment.

<Evaluation of laminate>
(Calculation of crystallite diameter of metallic silver)
The silver layer formed above was subjected to X-ray diffraction measurement using a thin film X-ray diffractometer (Bruker AXS, D8 DISCOVER with GADDS). CuKα rays (wavelength λ: 0.154 nm) were used as the X-ray source, and the measurement angle (2θ) was set to 20 to 100°. The respective measurement angles and the Miller indices of the peaks shown by X-ray diffraction are as follows, and the crystallite diameter was calculated in consideration of the crystal orientation.
Measuring angles: 38.1° (111), 44.2° (200), 64.4° (220), 77.4° (311), 81.5° (222), 97.8° (400).
Here, according to the Stokes-Wilson theory, the crystallite diameter was calculated based on the above Scherrer's equation in consideration of the size spread that does not depend on the crystal shape. The results are shown in Table 2.

(Measurement of volume resistivity of silver layer)
About the laminated body obtained above, the thickness T (cm) of the formed silver layer was measured using the laser microscope ("VK-X100" by KEYENCE CORPORATION). Moreover, the surface resistance value of the formed silver layer was measured by the 4-terminal method using a resistivity meter (“Loresta MCP-T610, PSP type probe” manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and the silver value was measured. The surface resistivity R (Ω/□) was calculated by multiplying the resistivity correction coefficient (4.04) calculated from the layer pattern shape and the probe shape. Then, the volume resistivity ρ (μΩ·cm) of the silver layer was calculated by the formula “ρ=R×T”. The results are shown in Table 2.

[Example 2]
<Manufacture of laminated body>
(Production of silver ink composition)
2-Methylacetoacetic acid silver was added to 2-ethylhexylamine (0.4 times the molar amount of silver 2-methylacetoacetate described below) in a beaker so that the liquid temperature was 50° C. or lower, and a mechanical stirrer was used. A liquid was obtained by stirring for 15 minutes. Formic acid (0.6 times the molar amount relative to silver 2-methylacetoacetate) was added dropwise to this liquid substance over 30 minutes using a syringe pump so that the temperature of the reaction liquid was 50° C. or lower. After the addition of formic acid was completed, the reaction solution was further stirred at 25°C for 1 hour, and then dodecane was added to the reaction solution so that the ratio of the compounded amount to the total amount of the compounded components was 11% by mass, and the compounded components were homogeneous. A silver ink composition was obtained by stirring at 25° C. until Table 1 shows the types and mixing ratios of the respective components.

(Manufacture of laminated body)
Lamination was performed in the same manner as in Example 1 except that the silver ink composition obtained above was used, and the spin coating conditions were 4500 rpm and 15 seconds instead of 7500 rpm and 30 seconds when the silver layer was formed. Got the body

<Evaluation of laminate>
The laminate obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Production and evaluation of laminated body>
[Example 3]
As shown in Tables 1 and 2, instead of heating the coated substrate for 2 minutes in a steam atmosphere at 80° C. and 100% relative humidity at the time of forming the silver layer, 120° C. and 100% relative humidity were used. A laminate was produced and evaluated in the same manner as in Example 1, except that the laminate was placed in a water vapor atmosphere of 2% for 2 minutes for heat treatment. The results are shown in Table 2.

[Example 4]
As shown in Tables 1 and 2, when the silver layer was formed, the coated substrate was dried at 80° C. for 1 minute, and then the substrate was placed in a steam atmosphere at 80° C. and a relative humidity of 100% for 2 minutes. A laminate was produced in the same manner as in Example 2 except that the coated substrate was heat-treated at 80° C. for 60 minutes by blowing hot air (air velocity: 15 m/sec) instead of the heat treatment, and evaluated. did. The results are shown in Table 2.

[Example 5]
As shown in Tables 1 and 2, when the silver layer was formed, the coated substrate was dried at 80° C. for 1 minute, and then the substrate was placed in a steam atmosphere at 80° C. and a relative humidity of 100% for 2 minutes. A laminated body was manufactured and evaluated in the same manner as in Example 2 except that the coated substrate was heat-treated at 120° C. for 60 minutes by blowing hot air (air velocity: 15 m/sec) instead of the heat treatment. did. The results are shown in Table 2.

[Comparative Example 1]
As shown in Tables 1 and 2, a silver ink composition containing metallic silver particles (“TEC-PA-010” manufactured by INK TEC) was used, and the spin coating condition was 7500 rpm when the silver layer was formed. The laminated body was manufactured and evaluated in the same manner as in Example 1 except that 30 seconds was replaced with 7500 rpm and 15 seconds. The results are shown in Table 2.

[Comparative example 2]
As shown in Tables 1 and 2, a silver ink composition containing metallic silver particles (“TEC-PA-010” manufactured by INK TEC) was used, and the spin coating condition was 7500 rpm when the silver layer was formed. , 7500 rpm for 15 seconds instead of 30 seconds, the coated substrate is dried at 80° C. for 1 minute, and the substrate is placed in a steam atmosphere at 80° C. and a relative humidity of 100% for 2 minutes and heated. A laminated body was produced and evaluated by the same method as in Example 1 except that the coated substrate was heat-treated at 80° C. for 60 minutes by blowing hot air (air velocity: 15 m/sec) instead of the treatment. .. The results are shown in Table 2.

[Comparative Example 3]
As shown in Tables 1 and 2, a silver ink composition containing metallic silver particles (“TEC-PA-010” manufactured by INK TEC) was used, and the spin coating condition was 7500 rpm when the silver layer was formed. , 15 seconds instead of 30 seconds, 7500 rpm, the coated substrate is dried at 80° C. for 1 minute, and the substrate is placed in a water vapor atmosphere at 80° C. and 100% relative humidity for 2 minutes for heating. A laminated body was produced and evaluated in the same manner as in Example 1 except that the coated substrate was heat-treated at 120° C. for 60 minutes by blowing hot air (air velocity: 15 m/sec) instead of the treatment. .. The results are shown in Table 2.

As is clear from the above results, in the laminates of Examples 1 to 5, the silver layer has a sufficiently low volume resistivity and excellent conductivity even though it was formed at a low heat treatment temperature of 120° C. or lower. It was In these examples, the crystallite diameter of the metallic silver constituting the silver layer was 16.8 nm or more.
On the other hand, in the laminates of Comparative Examples 1 to 3, it is considered that the heat treatment temperature was lower than that of the silver ink composition used, and the silver layer had high volume resistivity and poor conductivity. Was there.

[Example 6]
<Manufacture of laminated body>
(Production of silver ink composition)
A silver ink composition was obtained in the same manner as in Example 1. Table 3 shows the types and blending ratios of each blending component.

(Manufacture of laminated body)
Using the silver ink composition obtained above, a substrate on which the silver ink composition had been applied was obtained in the same manner as in Example 1.
Next, the coated base material is dried at 80° C. for 1 minute by blowing hot air (air velocity: 15 m/sec), and the coated base material is boiled at 80° C. for 2 minutes (80° C.). By heat (baking) treatment by immersing in silver hot water for 2 minutes), a silver layer having a size of 30 mm×30 mm and a thickness of 1 to 2 μm was formed on the base material to obtain a laminate. As hot water, distilled water heated to 80° C. was used. Table 4 shows the conditions for the heat treatment.

<Evaluation of laminate>
With respect to the silver layer formed above, the crystallite size of metallic silver was calculated by the same method as in Example 1. The results are shown in Table 4.
The volume resistivity ρ (μΩ·cm) of the silver layer obtained above was calculated by the same method as in Example 1. The results are shown in Table 4.

[Example 7]
<Manufacture of laminated body>
(Production of silver ink composition)
Silver acetoacetate was added to 2-ethylhexylamine (1.0 times the molar amount relative to silver acetoacetate described below) in a beaker so that the liquid temperature was 50° C. or lower, and a mechanical stirrer was used for 15 minutes. A liquid substance was obtained by stirring. Formic acid (1.2 times the molar amount relative to silver acetoacetate) was added dropwise to this liquid substance using a syringe pump so that the temperature of the reaction liquid was 50° C. or lower over 30 minutes. After the dropwise addition of formic acid, the reaction solution was stirred at 25° C. for another hour to obtain a silver ink composition. Table 3 shows the types and blending ratios of each blending component.

(Manufacture of laminated body)
A silver layer was formed in the same manner as in Example 6 except that the silver ink composition obtained above was used to produce a laminate. Table 4 shows the conditions for the heat treatment.

<Evaluation of laminate>
With respect to the silver layer formed above, the crystallite diameter of metallic silver was calculated by the same method as in Example 6. The results are shown in Table 4.
The volume resistivity ρ (μΩ·cm) of the silver layer obtained above was calculated by the same method as in Example 6. The results are shown in Table 4.

<Production and evaluation of laminated body>
[Example 8]
As shown in Tables 3 and 4, instead of heat-treating the coated substrate for 2 minutes at 80° C. in a water vapor atmosphere at the time of forming a silver layer, the substrate was heated at 80° C. and a relative humidity of 100%. A laminated body was produced and evaluated in the same manner as in Example 7 except that the laminate was placed and heat treated. The results are shown in Table 4.

[Example 9]
<Manufacture of laminated body>
(Production of silver ink composition)
Add silver acetonedicarboxylate to 2-ethylhexylamine (2.0 times molar amount relative to silver acetonedicarboxylate described below) in a beaker so that the liquid temperature becomes 50° C. or lower, and use a mechanical stirrer. A liquid substance was obtained by stirring for 15 minutes. Formic acid (2.0 times the molar amount of silver acetonedicarboxylate) was added dropwise to this liquid substance using a syringe pump so that the temperature of the reaction liquid was 50° C. or lower over 30 minutes. After the dropwise addition of formic acid, the reaction solution was stirred at 25° C. for another hour to obtain a silver ink composition. Table 3 shows the types and blending ratios of each blending component.

(Manufacture of laminated body)
A silver layer was formed in the same manner as in Example 6 except that the silver ink composition obtained above was used to produce a laminate. Table 4 shows the conditions for the heat treatment.

<Evaluation of laminate>
With respect to the silver layer formed above, the crystallite diameter of metallic silver was calculated by the same method as in Example 6. The results are shown in Table 4.
The volume resistivity ρ (μΩ·cm) of the silver layer obtained above was calculated by the same method as in Example 6. The results are shown in Table 4.

<Production and evaluation of laminated body>
[Example 10]
As shown in Tables 3 and 4, instead of heat-treating the coated base material at 80° C. for 2 minutes in a water vapor atmosphere at 80° C. and a relative humidity of 100% during the silver layer formation. A laminate was produced and evaluated in the same manner as in Example 9 except that the laminate was placed for a heat treatment and was heat treated. The results are shown in Table 4.

<Production and evaluation of laminated body>
[Comparative Example 4]
As shown in Tables 1 to 4, instead of heat treatment by placing the coated substrate in a steam atmosphere at 80° C. and a relative humidity of 100% for 2 minutes at the time of forming the silver layer, instead of heating at 80° C. for 2 minutes. A laminate was produced and evaluated in the same manner as in Comparative Example 1 except that it was boiled in water and heat-treated. As hot water, distilled water heated to 80° C. was used. The results are shown in Table 4.

<Production and evaluation of laminated body>
[Comparative Example 5]
As shown in Tables 3 and 4, instead of drying the coated substrate for 1 minute at 80° C. by blowing hot air (wind speed: 15 m/sec) during the formation of the silver layer, blowing hot air (air velocity) : 15 m/sec), a laminated body was produced and evaluated in the same manner as in Comparative Example 4 except that the coated substrate was dried at 120° C. for 1 minute. The results are shown in Table 4.

As is clear from the above results, in the laminated bodies of Examples 6 to 10, the silver layer was formed even though the heat treatment temperature was as low as 80° C. or lower and the heat treatment method was changed. Had a sufficiently low volume resistivity and was excellent in conductivity. In these examples, the crystallite diameter of the metallic silver forming the silver layer was 22.1 nm or more.
On the other hand, in the laminates of Comparative Examples 4 to 5, it is considered that the heat treatment temperature was lower than that of the silver ink composition used, and the silver layer had high volume resistivity and poor conductivity. Was there.

INDUSTRIAL APPLICABILITY The present invention can be used for various electronic devices including a metallic silver layer on a base material such as a wiring board, an electromagnetic wave shield, a touch panel, and an antenna of a wireless communication device housing.

1 Laminated body 11 Base material 11a One main surface (front surface) of the base material
11b The other main surface (back surface) of the base material
12 silver layers

Claims (7)

Metallic silver having a crystallite diameter of 22.1 nm or more and a volume resistivity of 8 μΩ·cm or less. The metallic silver according to claim 1, wherein the crystallite size is 22.1 nm or more and 80 nm or less. A metal comprising a silver β-ketocarboxylate represented by the following general formula (1), which has a crystallite diameter of 15 nm or more and has a volume resistivity of 8 μΩ·cm or less. Silver manufacturing method.

(In the formula, R is an aliphatic hydrocarbon group having 1 to 20 carbon atoms in which one or more hydrogen atoms may be substituted with a substituent, a phenyl group, a hydroxyl group, an amino group, or a general formula “R ¹ -CY”. ¹ ₂ - "," ^CY _{1 3} - "," ^R 1 -CHY ¹ - "," ^{R 2} O - "," ^R 5 ^{R 4} N -, "" _{^{(R 3 O) 2 CY 1}} - "or" ^{R 6 -C (= O) -CY} 1 2 - be a group represented by ";
Y ¹ is each independently a fluorine atom, a chlorine atom, a bromine atom or a hydrogen atom; R ¹ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group; R ² is a fat having 1 to 20 carbon atoms R ³ is an aliphatic hydrocarbon group having 1 to 16 carbon atoms; R ⁴ and R ⁵ are each independently an aliphatic hydrocarbon group having 1 to 18 carbon atoms; R ⁶ is An aliphatic hydrocarbon group having 1 to 19 carbon atoms, a hydroxyl group or a group represented by the formula "AgO-";
X ¹ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a phenyl group in which one or more hydrogen atoms may be substituted with a substituent, a benzyl group, a cyano group, N - phthaloyl-3-aminopropyl group, 2-ethoxyethyl vinyl group, or the general formula ^{"R 7} O -", ^{"R 7} S -", ^"R 7 -C (= O) -" or ^"R 7 -C ( =O)-O-";
R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group, or a phenyl group or diphenyl group in which one or more hydrogen atoms may be substituted with a substituent. ) In the step of forming the metallic silver, the silver ink composition containing the silver β-ketocarboxylate is heat-treated under non-humidified conditions, and then, further under humidified conditions or by contact with a heated liquid. The method for producing metallic silver according to claim 3 , wherein the metallic silver is formed by heat treatment. A laminate comprising a layer comprising the metallic silver according to claim 1 on a substrate. The laminate according to claim 5 , wherein the substrate has a thickness of 0.5 to 5000 µm, and the layer made of the metallic silver has a thickness of 0.01 to 5 µm. The laminate according to claim 5 , wherein the base material has a deflection temperature under load of 120° C. or less when the deflection amount is 0.25 mm at a bending stress of 1.8 MPa specified by ASTM D648.

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