JP6650295B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring board.

  A wiring board having a conductive thin wire formed on a substrate is widely used as a member for a transparent electrode, an electromagnetic wave shield, a touch panel and the like in various electronic devices. In particular, the demand for touch panels is rapidly increasing in various display elements including information communication devices such as mobile phones, and wiring boards using transparent substrates are important members.

  On the other hand, as a circuit board provided with wiring, for example, a pattern is formed with a conductive ink containing conductive particles such as silver by a screen printing method or the like, and this is heat-treated at a relatively low temperature of about 150 ° C. Accordingly, a device manufactured by forming a wiring pattern is disclosed, and a wiring having a line width of about 50 to 70 μm can be formed, and it is also disclosed that the wiring can be applied to the manufacture of a touch panel (see Patent Document 1). ).

JP 2012-253172 A

However, in recent wiring boards used in touch panels and the like as described above, the line width of the wiring is not sufficient at about 50 μm, and for example, the formation of finer fine lines having a line width of 20 μm or less is required. . In the method disclosed in Patent Document 1, it is difficult to form such a conductive thin wire, and it is necessary to rely on an etching method. However, when the etching method is applied, the process becomes complicated, An extra step such as waste liquid treatment is also required, and there is a problem that the method of manufacturing a wiring board becomes complicated.
In addition, wiring such as a touch panel is required to have appropriate surface roughness so that visibility due to light reflection is suppressed and other layers are easily stacked.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a wiring board on which conductive fine wires having an appropriate surface roughness can be manufactured by a simple method.

The present invention includes a silver fine line formed on a substrate by a printing method, wherein the silver fine line has a width of 20 μm or less and an aspect ratio of 0.013 in a cross section perpendicular to the line length direction. The width is 0.025 or less, the top is smaller in width than the contact portion with the substrate, and the surface roughness of the fine silver wire is 0.25 μm or more and 0.35 μm or less.
In the wiring board of the present invention, the silver fine wire preferably has a volume resistivity of 15 μΩ · cm or less.

  The wiring board of the present invention can be manufactured by a simple method, and has a conductive fine wire having an appropriate surface roughness.

1 is a front view schematically illustrating an example of a wiring board according to the present invention, and a cross-sectional view taken along line II of the wiring board. It is sectional drawing which shows typically an example of the metal wire of another shape in this invention. It is sectional drawing which shows an example of the thin metal wire formed by the etching method typically.

<< Wiring board >>
The wiring board according to the present invention includes a fine silver wire formed on a substrate by a printing method, wherein the fine silver wire has a width of 20 μm or less in a cross section in a direction perpendicular to the line length direction, and an aspect ratio of Is 0.013 to 0.025, the top is smaller in width than the contact portion with the substrate, and the surface roughness of the fine silver wire is 0.25 μm or more and 0.35 μm or less.
INDUSTRIAL APPLICABILITY The wiring board according to the present invention has a small line width of the fine silver wire, has the specific shape described above, and is suitable as a member for an electromagnetic wave shield, a touch panel, and the like in various electronic devices.

FIG. 1A is a front view schematically showing an example of a wiring board according to the present invention, and FIG. 1B is a cross-sectional view taken along line II of the wiring board shown in FIG. FIG. 4 is a cross-sectional view in a direction perpendicular to a line length (longitudinal) direction of the silver wire.
The wiring board 1 shown here comprises a plurality of linear silver fine wires 12 on a surface (one main surface) 11a of a substrate 11, and the plurality of silver fine wires 12 are orthogonal to each other. It is arranged in parallel to the direction and forms a mesh.

<Substrate>
The substrate 11 is preferably in the form of a film or a sheet, and preferably has a thickness of 0.5 to 5000 μm, more preferably 0.5 to 2500 μm.

The material of the substrate 11 is not particularly limited and may be selected according to the purpose. However, a material having heat resistance that does not deteriorate during the formation of the fine silver wires 12 by heat treatment of the silver ink composition described below is preferable, and has light transmittance. Are preferred.
Specific examples of the material of the substrate 11 include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polymethylpentene (PMP), polycycloolefin, polystyrene (PS), Acrylic resin such as polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), AS resin, ABS resin, polyamide (PA), polyimide, polyamide imide (PAI), polyacetal, polyethylene terephthalate (PET), polybutylene terephthalate ( PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polyphenylene sulfide (PPS), polysulfone (PSF), polyether sulfone (PE ), Polyether ketone (PEK), polyether ether ketone (PEEK), polycarbonate (PC), polyurethane, polyphenylene ether (PPE), modified polyphenylene ether (m-PPE), polyarylate, epoxy resin, melamine resin, phenol resin And synthetic resins such as urea resins.
In addition, as the material of the substrate 11, other than the above, ceramics such as glass and silicon can be exemplified.
Further, the substrate 11 may be a combination of two or more materials such as a glass epoxy resin and a polymer alloy.

The substrate 11 may be composed of a single layer, or may be composed of two or more layers. When the substrate 11 includes a plurality of layers, the plurality of layers may be the same or different from each other. That is, all the layers may be the same, all the layers may be different, or only some of the 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, that a plurality of layers are 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 substrate 11 includes a plurality of layers, the total thickness of each layer may be set to the preferable thickness of the substrate 11 described above.

<Silver wire>
In the present invention, the width of the fine silver wire 12 in the cross section perpendicular to the line length direction, that is, the width W shown in FIG. 1B is 20 μm or less. In the present invention, the width W shown in FIG. 1B is preferably 15 μm or less, more preferably 10 μm or less, and particularly preferably 7 μm or less.
In the present invention, in order to form a silver fine line having a line width in the above range, a silver plate having a groove having a width equal to or smaller than the desired silver fine line by about several μm may be used.
For example, in order to form a silver fine line having a width W of about 18 to 20 μm, a plate having a groove having a width of 17 μm is preferable, and to form a silver fine line having a width W of about 8 to 10 μm, a plate having a width of 7 μm is preferable. A plate having a groove having a width of 4 μm is preferable for forming a fine silver wire having a width W of about 5 to 6 μm.
Further, as shown in FIG. 1B, the cross-sectional shape of the fine silver wire 12 is a semi-elliptical shape obtained by cutting out a substantially half area in the minor axis direction of the ellipse. In the present invention, as described above, in the cross section, the width of the fine silver wire 12 is smaller at the top than at the contact portion with the substrate 11.

In the present invention, the cross-sectional shape of the fine silver wire 12 is not limited to this, and for example, a trapezoidal shape as shown in FIG. 2A, a triangular shape as shown in FIG. 2B, and a triangular shape as shown in FIG. Other shapes, such as a composite shape in which two or more types of shapes are combined as shown, may be used, and in FIGS. 2A to 2C, the shape may be a rounded corner.
As shown in FIG. 2B, when the top of the silver wire 12 is non-planar in the cross section, the width of the top of the silver wire 12 is naturally smaller than the contact portion with the substrate 11 (width). Is zero). Then, as shown in FIG. 2A and FIG. 2C, when the top of the silver fine wire 12 is a plane in the cross section, the width of the plane portion is different from the width of the silver fine wire 12 with the substrate 11. It is smaller than the width of the contact part.

Further, here, the cross-sectional shape of the fine silver wire 12 is symmetrical toward the paper surface. However, the present invention is not limited to this, and may be asymmetrical.
Further, here, the cross section of the silver fine wire 12 is schematically shown, and the surface of the silver fine wire 12 is smooth. However, the present invention is not limited to this, and the surface of the silver fine wire 12 is regular or irregular. Irregular irregular surfaces may be used.
That is, the cross-sectional shape of the fine silver wire 12 shown in FIGS. 1A, 1B, 2A, 2B, and 2C is only a part of the example. The cross-sectional shape of the fine silver wire 12 is not particularly limited as long as it has the features of the present invention.

  In the cross section, it is preferable that, in the cross section, a region whose width becomes narrower as the height from the surface 11a of the substrate 11 becomes higher occupies 80% or more in the height direction of the silver fine wire 12, It preferably occupies 85% or more, more preferably 90% or more, particularly preferably 95% or more, and may occupy 100%. The silver fine wire 12 preferably has such a cross section in the entire region in the line length direction.

  The silver fine wire 12 is typically formed by a printing method, and thus has a specific shape as described above.

On the other hand, the thin silver wire formed by the etching method typically has an inverted trapezoidal shape as shown in FIG. 3 or an inverted trapezoidal shape close to a square shape.
For example, when a coating layer (not shown) is formed on the surface 11a of the substrate 11 so as to cover the silver wire 12, the symbol S indicates that the cross-sectional shape of the silver wire is as shown in FIG. In the region near the root portion (contact portion with the substrate) of the shown silver fine wire, a void portion is likely to be formed because a covering layer cannot be formed. On the other hand, when the fine silver wire 12 has a shape as shown in FIGS. 1 (a), 1 (b), 2 (a), 2 (b), and 2 (c), as described above. The generation of a large void is highly suppressed. Further, especially when the surface of the fine silver wire 12 does not have a sharp shape as shown in FIG. 1 (b), the structure of the coating layer can be stably maintained. Can be maintained for a long time.

The silver fine wire 12 has a ratio of the height H to the width W (H / W) in the cross section, that is, the aspect ratio is 0.013 or more and 0.025 or less. In the present invention, it is more preferably 0.015 or more, and particularly preferably 0.016 or more.
The fine silver wire included in the wiring board of the present invention has a high aspect ratio as described above. For this reason, even if it is a finer silver fine line with a small line width, a silver fine line having good conductivity can be obtained.
The silver wire 12 having such a shape becomes more suitable as a member such as an electromagnetic wave shield and a touch panel in various electronic devices.

The pitch (distance between adjacent silver wires 12) P of the silver wires 12 can be set arbitrarily according to the purpose. For example, when the wiring board 1 is used as a member for an electromagnetic wave shield, a touch panel, or the like, 50 to 50 mm is used. It is preferably 320 μm, more preferably 70 to 260 μm.
The pitches P of the silver wires 12 may be all the same, may be all different, or may be partially different. For example, the pitches P of the silver wires 12 may be the same or different in two orthogonal directions.

  Silver wire 12 has a variation rate of width W ({[maximum value of W] − [minimum value of W]}} / [average value of W] × 100) of 20% or less in the line length (longitudinal) direction. Preferably, it is not less than 10%.

In the present invention, the surface roughness of the fine silver wire is 0.25 μm or more and 0.35 μm or less.
The surface roughness is based on JIS B0601: 2001 (ISO4287: 1997), which means arithmetic average roughness (Ra), and only a reference length 1 is extracted from a roughness curve in the direction of the average line. When the X axis is taken in the direction of the average line of the sampled portion and the Y axis is taken in the direction of the vertical magnification, and the roughness curve is represented by y = Z (x), the value obtained by the following equation (II) is obtained. It is displayed in units of micrometers (μm).

In the present invention, the surface roughness (Ra) of the fine silver wire is preferably 0.34 μm or less, more preferably 0.33 μm or less.
The silver fine wire included in the wiring board of the present invention is not too smooth because the surface roughness is equal to or more than the lower limit, and a moderate roughness can be realized, for example, when used for a touch panel or the like, when viewed from a specific direction. Light reflection can be suppressed appropriately. Therefore, visibility of the wiring due to light reflection can be suppressed.
Further, when the surface roughness is equal to or less than the above upper limit, an appropriate wettability can be imparted to the wiring. For example, when another substance is laminated on the wiring, good wettability can be obtained.

The silver fine wire 12 is mainly composed of metallic silver, and the ratio of metallic silver is sufficiently high that it can be considered that the metallic silver is composed of only metallic silver, and the ratio of metallic silver in the fine silver wire 12 is preferably It is 99% by mass or more. The upper limit of the ratio of metallic silver in the fine silver wire 12 is, for example, 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.
The silver fine wire 12 has high conductivity, and the volume resistivity of the silver fine wire 12 is preferably 15 μΩ · cm or less, more preferably 12 μΩ · cm or less, and particularly preferably 10 μΩ · cm or less.

  The difference between the light transmittance of the wiring board 1 and the light transmittance of the substrate 11 on which the silver fine wires 12 are not formed is preferably 15% or less, and more preferably 12% or less, for the light having the same wavelength. More preferably, it is particularly preferably 10% or less. By satisfying such conditions, the wiring board 1 becomes more suitable as a member for an electromagnetic wave shield, a touch panel, and the like in various electronic devices.

  In the present invention, the “light transmittance of the wiring board” refers to the light transmission in the thickness direction of the wiring board in an arbitrary region including both a portion where the fine silver wire is formed and a portion where the fine silver wire is not formed (that is, the substrate). Mean transmittance, the average of light transmittance obtained from the light transmittance in the area of the wiring board affected by the silver fine lines and the light transmittance in the area of the wiring board not affected by the silver fine lines. Value or an approximation to this average value.

  In the present invention, the light for measuring the transmittance is visible light, and its wavelength is preferably from 360 to 830 nm. The difference in light transmittance described above is obtained with light having the same wavelength.

  In the present invention, the difference between the light transmittance of the above-described wiring board and the light transmittance of a substrate on which silver fine lines are not formed (a substrate not affected by the silver fine lines) is due to the provision of the silver fine lines. This reflects the degree of decrease in light transmittance, but is suppressed to a small value due to the fine silver fine lines.

  The wiring board 1 may have one or more other configurations other than the substrate 11 and the fine silver wires 12 as long as the effects of the present invention are not impaired. The other configurations can be arbitrarily selected according to the purpose.

Here, as the wiring board, an example is shown in which a plurality of silver fine wires are arranged in parallel in two orthogonal directions to form a mesh, but the wiring board according to the present embodiment is not limited to this. Alternatively, the fine silver wire may form another pattern.
As other patterns formed by the silver fine lines, the angle at which a plurality of silver fine lines intersect (intersect) is not 90 ° as described above but an angle other than 90 °, and a part or all of the silver fine lines. Is not a straight line but a curve, and a plurality of silver fine lines are arranged without intersecting (for example, a case where a plurality of silver fine lines are arranged in parallel in one direction without intersecting, Are formed).
The pattern of the fine silver wire included in the wiring board may be only one kind or two or more kinds. When there are two or more kinds, the combination can be arbitrarily selected.

<< Production method of wiring board >>
The wiring board according to the present invention can be manufactured by a manufacturing method including a step of forming fine silver wires on a substrate by a printing method.

  For the silver fine wire, a composition for forming the silver fine wire (hereinafter, may be abbreviated as “composition for silver fine wire”) is prepared, and a pattern is formed on the substrate by a printing method using the composition. It can be formed by appropriately selecting and performing a solidification treatment such as heating or baking. The heat treatment may be performed also as a drying treatment.

In the present invention, a known method can be applied as a printing method, among which intaglio printing represented by a gravure printing method is preferable, and a gravure offset printing method is most preferable.
The printing device used in the present invention may also be a known device. For example, in the case of intaglio printing represented by a gravure printing method, an intaglio plate having a metal and having a groove having a shape of a silver fine wire on the surface is used. be able to. As the offset roll, a metal cylinder body whose surface is covered with a blanket material can be used. As the material of the blanket material, silicone resin, fluorine resin, urethane resin, synthetic rubber, natural rubber, etc. In particular, silicone resin is preferable in that it has high durability and oil resistance, and has sufficient elasticity and moderate stiffness, and gravure offset printing is performed on a hard substrate. It is particularly suitable for

In the present invention, it is preferable to use a silver ink composition containing a material for forming metallic silver as the silver fine wire composition.
The forming material of the metallic silver may be any material having a silver atom (element) and generating metallic silver by a structural change such as decomposition, and may be a silver salt, a silver complex, an organic silver compound (a compound having a silver-carbon bond). ) Can be exemplified. 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. Above all, the material for forming metallic silver is preferably one that decomposes by heating to form metallic silver, and is preferably a silver salt.
By using the forming material of metallic silver, metallic silver is generated from the material, and a fine silver wire containing the metallic silver is formed. As described above, the silver fine wire in this case is mainly composed of metallic silver, and the ratio of metallic silver is sufficiently high.

  The silver ink composition is preferably one in which a material for forming metallic silver is uniformly dispersed.

[Silver carboxylate]
Examples of the material for forming metallic silver include silver carboxylate having a group represented by the formula “—COOAg”.
In the present invention, one kind of silver carboxylate may be used alone, or two or more kinds may be used in combination. When two or more kinds are used in combination, the combination and 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 the silver carboxylate is not particularly limited.

The silver carboxylate is represented by silver β-ketocarboxylate represented by the following general formula (1) (hereinafter sometimes abbreviated as “silver β-ketocarboxylate (1)”) and the following general formula (4). It is preferably at least one selected from the group consisting of silver carboxylate (hereinafter sometimes abbreviated as “silver carboxylate (4)”).
In the present specification, the term “silver carboxylate” is not limited to “silver β-ketocarboxylate (1)” and “silver carboxylate (4)” unless otherwise specified. It is intended to mean “silver carboxylate having a group represented by the formula“ —COOAg ”” inclusive.

（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 represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms which may be substituted with one or more hydrogen atoms or a phenyl group, a hydroxyl group, an amino group, or a compound represented by 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 - be a group represented by ";
Y ¹ is each independently a fluorine atom, chlorine atom, bromine atom or hydrogen atom; R ¹ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group; R ² is an aliphatic 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 is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a phenyl group or a benzyl group in which one or more hydrogen atoms may be substituted with a substituent, a cyano group, - 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 ( ＯO) -O- ";
R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group, or a phenyl group or a 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。）

(Wherein, 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”, wherein the aliphatic hydrocarbon group is a methylene group. Wherein one or more of the methylene groups may be substituted with a carbonyl group.)

(Silver β-ketocarboxylate (1))
Silver β-ketocarboxylate (1) is represented by the general formula (1).
In the formula, R represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms which may be substituted with one or more hydrogen atoms or a phenyl group, a hydroxyl group, an amino group, or a compound represented by 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 any of linear, branched and cyclic (aliphatic cyclic group), and when it is cyclic, it may be monocyclic or polycyclic. . Further, the aliphatic hydrocarbon group may be any of a saturated aliphatic hydrocarbon group and an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms. Preferred examples of the 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 a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a -Pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylbutyl, 2-methylbutyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4- Methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 2,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 3-ethylbutyl A 1-ethyl-1-methylpropyl group, an n-heptyl group, a 1-methylhexyl group, a 2-methylhexyl group, a 3-methylhexyl group, -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, 1-ethylpentyl, 2-ethylpentyl, 3-ethylpentyl, 4-ethylpentyl, 2,2,3-trimethylbutyl, 1-propylbutyl, 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, -Dimethylhexyl, 4,4-dimethylhexyl, 5,5-dimethylhexyl, 1-propylpentyl, 2-propylpentyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl Pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group and icosyl group.
Examples of the cyclic alkyl group represented by R include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a norbornyl group, an isobornyl group, a 1-adamantyl group, An adamantyl group and a tricyclodecyl group can be exemplified.

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) Can be exemplified by a group substituted by a double bond (C = C).
Examples of the alkynyl group for R include one single bond (C—C) between carbon atoms of the alkyl group for R such as an ethynyl group (—C≡CH) and a propargyl group (—CH ₂ —C≡CH). ) Is substituted by a triple bond (C≡C).

  The aliphatic hydrocarbon group having 1 to 20 carbon atoms in R may have one or more hydrogen atoms substituted with a substituent, and preferred examples of the substituent include a fluorine atom, a chlorine atom and a bromine atom. . The number and position of the substituent are not particularly limited. When the number of the substituents is plural, these plural substituents may be the same or different. 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 for 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 formed by bonding the aliphatic hydrocarbon group to an oxygen atom, a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group (—OH), a cyano group (—C≡N), and a phenoxy group (—O— C ₆ H ₅ ) and the like, and the number and positions of the substituents are not particularly limited. When the number of the substituents is plural, these plural substituents may be the same or different.
Exemplified as the aliphatic hydrocarbon group as the substituent is the same as the above-mentioned aliphatic hydrocarbon group for R except that the aliphatic hydrocarbon group has 1 to 16 carbon atoms.

Y ^{1 in} R is each 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 in 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-mentioned aliphatic hydrocarbon group in R.
R ³ in R is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, and the same as the above-mentioned aliphatic hydrocarbon group in R can be exemplified except that the carbon number 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 or different from each other, and may be the same as the above-mentioned aliphatic hydrocarbon group for R, except that they have 1 to 18 carbon atoms.
R ⁶ in R is an aliphatic hydrocarbon group of 1 to 19 carbon atoms, a group represented by a hydroxyl group or a formula "AgO-" The aliphatic hydrocarbon group for R ^6,. 1 to carbon atoms Except for the point of 19, the same as the above-mentioned 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 is 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 A benzyl group (C ₆ H ₅ —CH ₂ —), a cyano group, an N-phthaloyl-3-aminopropyl group, a 2-ethoxyvinyl group (C ₂ H ₅ —O—CH ＝ CH—), or a compound represented by the general formula “R ⁷ O - "," ^{R 7} S - "," ^R 7 -C (= O) - "or" a group represented by ^R 7 -C (= O) -O-. "
As the aliphatic hydrocarbon group having 1 to 20 carbon atoms for X ^1, the same as the aforementioned aliphatic hydrocarbon group for R can be exemplified.

The halogen atom in X ^1, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom can be exemplified.
The phenyl group and the benzyl group in X ¹ may have one or more hydrogen atoms substituted with a substituent. Preferred examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom). A nitro group (—NO ₂ ) can be exemplified, and the number and position of the substituent are not particularly limited. When the number of the substituents is plural, these plural substituents may be the same or different.

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

In the general formula (1), two X ¹ may be bonded as a single group via a double bond to a carbon atom sandwiched between two carbonyl groups. A group represented by the formula “＝ CH—C ₆ H ₄ —NO ₂ ” can be exemplified.

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) —” among the above. , It is preferable that at least one X ¹ is a hydrogen atom.

Silver β-ketocarboxylate (1) is composed of 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 pivaloyl acetate ((CH ₃ ) ₃ C—C (＝ O) —CH ₂ —C (＝ O) —OAg), silver caproyl 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 (C _{H 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), silver isobutyryl acetoacetate ((CH ₃ ) ₂ CH—C (＝ O) —CH ₂ —C (＝ O) —CH ₂ -C (= O) -OAg), 2- acetyl pivaloyl silver acetate _{((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) - Ag), or is preferably acetone dicarboxylic silver _{(AgO-C (= O)} -CH 2 -C (= O) -CH 2 -C (= O) -OAg).

  Silver β-ketocarboxylate (1) can further reduce the concentration of remaining raw materials and impurities in a conductor (metal silver) formed by a solidification treatment such as a drying treatment or a heating (firing) treatment. As the amount of raw materials and impurities is smaller, for example, the formed metal silver contacts better, conduction is facilitated, and the resistivity decreases.

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

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

(Silver carboxylate (4))
The silver carboxylate (4) is represented by the general formula (4).
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 the same as the above-mentioned aliphatic hydrocarbon group for R except that the aliphatic hydrocarbon group 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 groups that may be substituted with a carbonyl group are not particularly limited, and all methylene groups may be substituted with a carbonyl group. Here, the “methylene group” means not only a group represented by a single formula “—CH ₂ —” but also one of an alkylene group in which a plurality of groups represented by the formula “—CH ₂ —” are linked. And a group represented by the formula “—CH ₂ —”.

Silver carboxylate (4) includes silver pyruvate (CH ₃ —C (＝ O) —C (＝ O) —OAg), silver acetate (CH ₃ —C (＝ O) —OAg), and 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 oxide (AgO—C (＝ O) —C (＝ O) —OAg) or silver malonate (AgO—C (＝ O) —CH ₂ —C (＝ O) —OAg) is preferred. The silver oxalate (AgO—C (＝ O) —C (） O) —OAg) and silver malonate (AgO—C (＝ O) —CH ₂ —C (＝ O) —OAg) Of the groups represented by the formula “—COOAg”, one of which is a group represented by the formula “—COOH” (HO—C (＝ O) —C (＝ O) —OAg, HO _{-C (= O) -CH 2 -C} (= O) -OAg) it is also preferred.

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

  In the present invention, as the silver carboxylate (4), one type 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 ratio can be arbitrarily adjusted.

The silver carboxylate includes silver 2-methylacetoacetate, silver acetoacetate, silver 2-ethylacetoacetate, silver propionyl acetate, silver isobutyryl acetate, silver pivaloyl acetate, silver caproyl acetate, silver 2-n-butylacetoacetate, and 2-benzylacetate. Silver acetate, silver benzoyl acetate, silver pivaloylacetoacetate, silver isobutyryl acetoacetate, silver acetonedicarboxylate, silver pyruvate, silver acetate, silver butyrate, silver isobutyrate, silver 2-ethylhexanoate, silver neodecanoate, silver It is preferably at least one selected from the group consisting of silver acid and silver malonate.
Among these silver carboxylate, silver 2-methylacetoacetate and silver acetoacetate are excellent in compatibility with nitrogen-containing compounds (among others, amine compounds) described later, and are particularly suitable for increasing the concentration of the silver ink composition. Are listed.

In the silver ink composition, the content of silver derived from the metal silver forming material is preferably 5% by mass or more, and more preferably 10% by mass or more. By being in such a range, the formed conductor (metallic 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 is preferably 25% by mass in consideration of handleability and the like.
In the present specification, `` silver derived from the metal silver forming material '' means silver in the metal silver forming material blended at the time of manufacturing the silver ink composition, unless otherwise specified. The concept includes both silver constituting the metal silver forming material after the compounding, and silver and silver itself in a decomposition product generated by decomposition of the metal silver forming material after the compounding.

[Nitrogen-containing compound]
The silver ink composition preferably further contains 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 an amine compound having 25 or less carbon atoms (hereinafter may be abbreviated as “amine compound”), a quaternary ammonium salt having 25 or less carbon atoms (hereinafter abbreviated as “quaternary ammonium salt”). ), Ammonia, an ammonium salt obtained by reacting an amine compound having 25 or less carbon atoms with an acid (hereinafter may be abbreviated as “ammonium salt derived from an amine compound”), and ammonia reacting with an acid. At least one selected from the group consisting of ammonium salts (hereinafter sometimes abbreviated as "ammonium salts 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 ratio thereof can be arbitrarily adjusted.

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

  Examples of the primary amine include a monoalkylamine, a monoarylamine, a mono (heteroaryl) amine, and a 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 alkyl groups as those described above for R, and include linear or branched alkyl groups having 1 to 19 carbon atoms. It is preferably a chain alkyl group or a cyclic alkyl group having 3 to 7 carbon atoms.
Preferred examples of the monoalkylamine include n-butylamine, n-hexylamine, n-octylamine, n-dodecylamine, n-octadecylamine, sec-butylamine, tert-butylamine, isobutylamine and 3-aminoamine. Examples include pentane, 3-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, and a 2-naphthyl group, and preferably have 6 to 10 carbon atoms.

The heteroaryl group constituting the mono (heteroaryl) amine has a hetero atom as an atom constituting an aromatic ring skeleton, and the hetero atom includes a nitrogen atom, a sulfur atom, an oxygen atom, and a boron atom. Can be exemplified. The number of the hetero atoms constituting the aromatic ring skeleton is not particularly limited, and may be one or two or more. When there are two or more, these hetero atoms may be the same or different from each other. That is, these hetero atoms may be all the same, may be all different, or may be partially 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.

Examples of the heteroaryl group having a monocyclic structure having 1 to 4 nitrogen atoms include 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, 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 a single ring having one 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 one sulfur atom and having a single ring include a thienyl group, preferably a 3- to 8-membered ring, and more preferably a 5- to 6-membered ring.
In the heteroaryl group, examples of the monocyclic group having 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms include an oxazolyl group, an isoxazolyl group, an oxadiazolyl group, and a morpholinyl group. Preferably, the ring is a 5- to 6-membered ring.
Examples of the monocyclic 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 may be a 3- to 8-membered ring. Preferably, it is a 5- to 6-membered ring.
Examples of the heteroaryl group having 1 to 5 nitrogen atoms which are polycyclic include indolyl, isoindolyl, indolizinyl, benzimidazolyl, quinolyl, isoquinolyl, indazolyl, benzotriazolyl, tetra Examples include a zolopyridyl group, a tetrazolopyridazinyl group, and a dihydrotriazolopyridazinyl group, preferably a 7-12 membered ring, and more preferably a 9-10 membered ring.
In the heteroaryl group, examples of the polycyclic group having 1 to 3 sulfur atoms include a dithianaphthalenyl group and a benzothiophenyl group, and a 7 to 12 membered ring is preferable, and a 9 to 10 membered ring is preferable. More preferably, it is a ring.
In the heteroaryl group, examples of the polycyclic group having 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms include a benzooxazolyl group and a benzooxadiazolyl group. Preferably, the ring is a 9- to 10-membered ring.
In the heteroaryl group, examples of the polycyclic group having 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms include a benzothiazolyl group and a benzothiadiazolyl group, and may be a 7 to 12-membered ring. It is more preferably a 9- to 10-membered ring.

The diamine only has 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. Can be exemplified.
The diamine preferably has 1 to 10 carbon atoms, and more preferable examples include ethylenediamine, 1,3-diaminopropane and 1,4-diaminobutane.

  Examples of the secondary amine include dialkylamines, diarylamines, and di (heteroaryl) amines 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. The two alkyl groups in one molecule of the dialkylamine may be the same or different from each other.
Specific examples of the preferred 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 the 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. 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 and dialkylmonoarylamines in which one or more hydrogen atoms may be substituted with a substituent.

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. Is preferably a cyclic alkyl group. Further, the three alkyl groups in one molecule of the trialkylamine may be the same or different from each other. That is, all three alkyl groups may be the same, all may be different, or only some may be different.
Specific examples of the preferred 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 straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms, or 3 to 6 carbon atoms. 7 is preferably a cyclic alkyl group. The two alkyl groups in one molecule of the 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, examples of the quaternary ammonium salt include tetraalkylammonium halides in which one or more hydrogen atoms may be substituted with a substituent.
The alkyl group constituting the tetraalkylammonium halide is the same as the alkyl group constituting the monoalkylamine, and preferably has 1 to 19 carbon atoms. Further, the four alkyl groups in one molecule of the tetraalkylammonium halide may be the same or different from each other. That is, all of the four alkyl groups may be the same, all may be different, or only some may be different.
Examples of the halogen constituting the halogenated tetraalkylammonium include fluorine, chlorine, bromine and iodine.
Specific examples of the preferable tetraalkylammonium halide include dodecyltrimethylammonium bromide.

So far, the chain amine compound and the quaternary 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 (heterocyclic structure). (A ring skeleton structure). 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 an amine moiety or an ammonium salt moiety) structure may be monocyclic or polycyclic, and the number of ring members (number of atoms constituting a ring skeleton) is also particularly limited. And may be any of an aliphatic ring and an aromatic ring.
Preferable examples of the cyclic amine include pyridine.

  In the above primary amine, secondary amine, tertiary amine and quaternary ammonium salt, “hydrogen atom optionally substituted with a substituent” means a nitrogen atom constituting an amine moiety or an ammonium salt moiety. Is 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 a substituent. When the number of substituents is plural, these plural substituents may be the same or different. That is, a plurality of substituents may be the same, all may be different, or only a part may be different. Also, the position of the substituent is not particularly limited.

Examples of the substituent in the amine compound and the quaternary ammonium salt include an alkyl group, an aryl group, a halogen atom, a cyano group, a nitro group, a hydroxyl group, and a trifluoromethyl group (—CF ₃ ). 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 a cyclic alkyl group having 3 to 7 carbon atoms having an alkyl group having 1 to 5 carbon atoms. As the monoalkylamine having such a substituent, specifically, 2-phenylethylamine Benzylamine and 2,3-dimethylcyclohexylamine.
Further, the aryl group and the alkyl group which are substituents may further have one or more hydrogen atoms substituted with a halogen atom. Examples of the monoalkylamine having a substituent substituted with such a halogen atom include: And 2-bromobenzylamine. 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 a monoaryl having such a substituent. As the amine, specifically, bromophenylamine 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 dialkylamine has a substituent, the alkyl group has a hydroxyl group or an aryl group as a substituent, and is preferably a linear or branched alkyl group having 1 to 9 carbon atoms, 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, isobutylamine, 3-aminopentane, 3-methylbutylamine, 2-heptylamine, 2-aminooctane, 2-ethylhexylamine, 2-phenylethylamine, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, N-methyl-n-hexylamine, Diisobutylamine, N-methylbenzylamine, di (2-ethylhexyl) amine, 1,2-dimethyl-n-propylamine, N, N-dimethyl-n-octadecylamine or N, N-dimethylcyclohexylamine Is preferred.
Among these amine compounds, 2-ethylhexylamine has excellent compatibility with the silver carboxylate, is particularly suitable for increasing the concentration of the silver ink composition, and is particularly suitable for reducing the surface roughness of fine silver wires. Listed as suitable.

(Ammonium salt derived from amine compound)
In the present invention, the ammonium salt derived from the amine compound is an ammonium salt obtained by reacting the amine compound with an acid, and the acid may be an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, or an organic acid such as acetic acid. However, the type of the 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 salt derived from ammonia)
In the present invention, the ammonium salt derived from ammonia is an ammonium salt obtained by reacting ammonia with an acid. Here, the acid may be the same as the ammonium salt derived from the amine compound.
Examples of the ammonium salt derived from ammonia include ammonium chloride and the like, but are not limited thereto.

In the present invention, each of the amine compound, the quaternary ammonium salt, the ammonium salt derived from the amine compound and the ammonium salt derived from ammonia may be used alone or in combination of two or more. . When two or more kinds are used in combination, the combination and ratio can be arbitrarily adjusted.
As the nitrogen-containing compound, one selected from the group consisting of the amine compound, a quaternary ammonium salt, an ammonium salt derived from an amine compound, and an ammonium salt derived from ammonia may be used alone. More than one species may be used in combination. When two or more kinds are used in combination, the combination and 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, more preferably 0.3 to 5 mol, per 1 mol of the compounding material of the metallic silver. preferable. When the amount of the nitrogen-containing compound is within such a range, the silver ink composition has improved stability and the quality of the conductor (metal silver) is further improved. Further, the conductor can be formed more stably without performing heat treatment at a high temperature.

[Reducing agent]
The silver ink composition preferably contains a reducing agent in addition to the metal silver forming material. By adding a reducing agent, the silver ink composition can more easily 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 at least one reducing compound 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 sometimes simply referred to as “reducing compound”).
HC (= 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 It is. That is, the reducing 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.

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 for R in the general formula (1). Can be exemplified.

The alkoxy group having 20 or less carbon atoms in R ²¹ has 1 to 20 carbon atoms, and examples thereof include a monovalent group in which the alkyl group in R ²¹ is 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; Each of the alkyl groups has 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 any of linear, branched and cyclic, and has the same structure as that of R in the general formula (1) except that it has 1 to 19 carbon atoms. The same as the group can be exemplified.

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

Preferred reducing compounds include formic acid (H—C (−O) —OH); methyl formate (H—C (＝ O) —OCH ₃ ), and 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 Aldehydes such as —C (＝ O) — (CH ₂ ) ₂ CH ₃ ) and hexanal (H—C (＝ O) — (CH ₂ ) ₄ CH ₃ ); formamide (H—C (＝ O) —NH ₂ ) ), Formamides such as N, N-dimethylformamide (H—C (） O) —N (CH ₃ ) ₂ ) (groups represented by the formula “H—C (＝ O) —N (−) —”) And oxalic acid.

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

[alcohol]
It is preferable that the silver ink composition further contains an alcohol in addition to the metal silver forming material.

  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、それぞれ独立に水素原子、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 hydrogen atom, 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.)

(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 with a 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 aliphatic hydrocarbon group. Examples include 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.The hydrogen atom of the phenyl group in R may be substituted. The same as the above substituents. The number and the position of the substituents are not particularly limited. When the number of the substituents is plural, these plural substituents may be the same or different.

  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.

  Preferred acetylenic alcohols (2) include 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, and 2-propyne Examples thereof include -1-ol, 4-ethyl-1-octin-3-ol, and 3-ethyl-1-heptin-3-ol.

  When the acetylene alcohol (2) is used, the amount of the acetylene alcohol (2) in the silver ink composition is preferably 0.03 to 0.7 mol per 1 mol of the metal silver forming material. , 0.03 to 0.5 mol, more preferably 0.03 to 0.3 mol. When the amount of the acetylene alcohol (2) is in such a range, the stability of the silver ink composition is further improved.

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

[Other ingredients]
The silver ink composition may be one in which other components other than the metal silver forming material, the nitrogen-containing compound, the reducing agent and the alcohol are blended.
The other components in the silver ink composition can be arbitrarily selected according to the purpose, and are not particularly limited. Preferred examples include solvents other than alcohols, and arbitrarily selectable according to the types and amounts of the components. it can.
As the other components in the silver ink composition, one type 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 ratio can be arbitrarily adjusted.

  The solvent other than the alcohol can be arbitrarily selected depending on the type and amount of the components. Preferred solvents include, for example, aromatic hydrocarbons such as toluene, o-xylene, m-xylene and p-xylene; pentane, hexane, cyclohexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane Aliphatic hydrocarbons such as ethanol and 2-propanol; halogenated hydrocarbons such as dichloromethane and chloroform; esters such as ethyl acetate, monomethyl glutarate, and dimethyl glutarate; diethyl ether, tetrahydrofuran (THF) Ethers such as 1,2-dimethoxyethane (dimethylcellosolve); ketones such as acetone, methyl ethyl ketone (MEK) and cyclohexanone; nitriles such as acetonitrile; N, N-dimethylformamide (DMF) N, N-amides of dimethylacetamide, and the like, but not limited thereto.

The amount of the other components in the silver ink composition may be appropriately selected according to the type of the other components.
For example, when the other component is a solvent other than alcohol, the amount of the solvent may be selected depending on the purpose, such as the viscosity of the silver ink composition. , 0.5 mol to 5.0 mol, more preferably 0.5 mol to 3.5 mol, and particularly preferably 0.5 mol to 2.0 mol.
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 more preferably 5% by mass. % Is more preferable.
Even if the ratio of the compounding amount of the other component to the total amount of the compounding component is 0 mass, that is, the other component is not mixed, the silver ink composition sufficiently exerts its effect.

  The silver ink composition is preferably formed by blending one or both of the metal silver forming material, the nitrogen-containing compound, and the reducing agent and the alcohol, and the silver carboxylate, the nitrogen-containing compound, and the reducing agent. More preferably, one or both of alcohols are blended.

  In the silver ink composition, all of the components may be dissolved, or some or all of the components may be dispersed without being dissolved, but it is preferable that all of the components are dissolved. Preferably, the undissolved components are uniformly dispersed.

[Method for producing silver ink composition]
The silver ink composition is obtained by blending the metal silver forming material and components other than the metal silver forming material. After the components are blended, the resulting composition may be used as it is as a silver ink composition, or the composition obtained by performing known purification operations may be used as a silver ink composition. In the present invention, in particular, when silver β-ketocarboxylate (1) is used as a material for forming the metallic silver, impurities which impair conductivity are not generated at the time of blending each of the above components, or such impurities are not generated. Since the generation amount of impurities can be suppressed to an extremely small amount, a conductor (metallic silver) having sufficient conductivity can be obtained even when a silver ink composition that has not been subjected to a refining operation is used.

(Production method 1 of silver ink composition)
One embodiment of the method for producing a silver ink composition is obtained by blending a material for forming metallic silver and one or more selected from the group consisting of a nitrogen-containing compound, a reducing agent, alcohol and other components.
Among them, in the present invention, it is possible to add a metal silver forming material to a nitrogen-containing compound, then add a reducing agent, and then add an alcohol, and sequentially add and mix each component. preferable.

  The fine silver wire formed using the silver ink composition manufactured by adding and mixing the components in the above order has a line width of 20 μm or less and an aspect ratio of 0.013 or more and 0.025 or less. And the surface roughness can be set to 0.25 μm or more and 0.35 μm or less.

That is, in the present invention, when the silver ink composition is obtained by the method 1 for producing a silver ink composition, the first step of adding a forming material of metallic silver to the nitrogen-containing compound and the second step of further adding a reducing agent. It is preferable to be manufactured by a manufacturing method having a step and a third step of adding an alcohol and other components as necessary.
The metal silver forming material added in the first step is preferably the total amount of the metal silver forming material used in this manufacturing method.
The reducing agent added in the second step is preferably the total amount of the reducing agent used in this production method.
The alcohol and other components added in the third step are preferably the total amount of the alcohol and other components used in this production method.

(Production method 2 of silver ink composition)
As one embodiment of a method for producing a silver ink composition other than the method 1 for producing a silver ink composition, a metal forming material is dissolved or dispersed in a solvent, a nitrogen-containing compound is added, and then a reducing agent is added. , Followed by the addition of alcohol, the components are sequentially added and mixed.

  The fine silver wire formed using the silver ink composition manufactured by adding and mixing the components in the above order has a line width of 20 μm or less and an aspect ratio of 0.013 or more and 0.025 or less. And the surface roughness can be set to 0.25 μm or more and 0.35 μm or less.

That is, in the present invention, when the silver ink composition is obtained by the silver ink composition manufacturing method 2, a first step of dissolving or dispersing the metal silver forming material in a solvent and a step of further adding a nitrogen-containing compound are performed. It is preferably produced by a production method having two steps, a third step of further adding a reducing agent, and a fourth step of further adding an alcohol and other components as necessary.
The metal silver forming material to be dissolved or dispersed in the solvent in the first step is preferably the total amount of the metal silver forming material used in this production method.
The nitrogen-containing compound added in the second step is preferably the total amount of the nitrogen-containing compound used in this production method.
The reducing agent added in the third step is preferably the total amount of the reducing agent used in this production method.
The alcohol and other components added in the fourth step are preferably the total amount of the alcohol and other components used in this production method.

In the present invention, the reducing agent is preferably added dropwise, and by suppressing the fluctuation of the dropping speed, the surface roughness of metallic silver tends to be further reduced.
The mixing method is not particularly limited, a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer, a three-roll, kneader or a bead mill; a method of mixing by adding ultrasonic waves; What is necessary is just to select suitably from well-known methods.
In the case of uniformly dispersing the undissolved components in the silver ink composition, it is preferable to apply the method of dispersing using, for example, the above-described three-roll, kneader, or bead mill.

The temperature at the time of blending is not particularly limited as long as each blended component does not deteriorate, but is preferably -5 to 60 ° C. The temperature during 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 allows easy stirring.
The blending time is not particularly limited as long as each blended component does not deteriorate, but is preferably 10 minutes to 36 hours.

[carbon dioxide]
The silver ink composition may be one further supplied with carbon dioxide. Such a silver ink composition has a high viscosity and is suitable, for example, for thickening the ink.

Carbon dioxide may be supplied at any time during the production of the silver ink composition.
In the present invention, for example, carbon dioxide may be supplied before adding the reducing agent, and it can be arbitrarily selected according to the purpose.

Carbon dioxide (CO ₂ ) supplied at the time of mixing each component may be either gaseous or solid (dry ice), or may be both gaseous and solid. It is presumed that the supply of carbon dioxide causes the carbon dioxide to dissolve into the first mixture and act on each component, thereby increasing the viscosity of the resulting mixture of each component.

  The supply of the carbon dioxide gas may be performed by various known methods for blowing the gas into the liquid, and an appropriate supply method may be appropriately selected. For example, a method in which one end of a pipe is immersed in a first mixture, the other end is connected to a supply source of carbon dioxide gas, and the carbon dioxide gas is supplied to the first mixture through the pipe can be exemplified. At this time, the carbon dioxide gas may be supplied directly from the end of the pipe.However, for example, a porous material such as a porous material is provided with a number of voids that can be a gas flow path, and the introduced gas is diffused. A gas diffusion member that can be released as minute bubbles may be connected to the end of the pipe, and the carbon dioxide gas may be supplied through the 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 the carbon dioxide gas may be appropriately adjusted according to the viscosity of the target silver ink composition, and is not particularly limited. For example, in order to obtain about 100 to 1000 g of a silver ink composition having a viscosity at 20 to 25 ° C. of 5 Pa · s or more, it is preferable to supply 100 L or more of carbon dioxide gas, and it is more preferable to supply 200 L or more. Here, the viscosity of the silver ink composition at 20 to 25 ° C. has been described, but the temperature at the time of using the silver ink composition is not limited to 20 to 25 ° C. and can be arbitrarily selected.

The flow rate of the carbon dioxide gas may be appropriately adjusted in consideration of the required supply amount of the carbon dioxide gas, but is preferably 0.5 mL / min or more, preferably 1 mL / min or more per 1 g of the mixture of each component. 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 of each component in consideration of handling properties and the like.
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 mixture of the components at the time of supplying the carbon dioxide gas is preferably from 5 to 70 ° C, more preferably from 7 to 60 ° C, and particularly preferably from 10 to 50 ° C. When the temperature is equal to or higher than the lower limit, carbon dioxide can be supplied more efficiently. When the temperature is equal to or lower than the upper limit, a better quality silver ink composition with less impurities can be obtained.

  The flow rate and supply time of the carbon dioxide gas, and the temperature during the supply of the carbon dioxide gas may be adjusted to appropriate ranges while mutually considering each value. For example, even if the temperature is set low, the flow rate of the carbon dioxide gas is set to be large, or the supply time of the carbon dioxide gas is set to be long, or both are performed, so that the carbon dioxide gas can be efficiently formed. Can supply carbon. In addition, even if the flow rate of the carbon dioxide gas is set to a small value, the temperature can be increased, or the supply time of the carbon dioxide gas can be set to be longer, or both can be performed so that the carbon dioxide can be efficiently produced. Can be supplied. That is, the flow rate of the carbon dioxide gas, the numerical value in the above numerical range exemplified as the temperature at the time of carbon dioxide gas supply, by flexibly combining while considering the supply time of the carbon dioxide gas, silver ink of good quality The composition is obtained efficiently.

It is preferable to supply the carbon dioxide gas while stirring the mixture of each component. By doing so, the supplied carbon dioxide gas diffuses more evenly into the mixture of each component, and carbon dioxide can be supplied more efficiently.
The stirring method at this time may be the same as the mixing method at the time of producing the above silver ink composition without using carbon dioxide.

Dry ice (solid carbon dioxide) may be supplied by adding dry ice to a mixture of each component. Dry ice may be added all at once, or may be added stepwise (continuously in a time period during which no addition is performed).
The amount of dry ice used may be adjusted in consideration of the supply amount of the carbon dioxide gas.
During and after the addition of dry ice, it is preferable to stir the mixture of the components, for example, it is preferable to stir by the same method as in the production of the 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 at the time of supplying carbon dioxide gas. Further, the stirring time may be appropriately adjusted according to the stirring temperature.

  The silver ink composition supplied with carbon dioxide preferably has a viscosity at 20 to 25 ° C. of 1 Pa · s or more.

  For example, when the reducing agent is compounded, the obtained compound (silver ink composition) relatively easily generates heat. Then, when the temperature at the time of compounding the reducing agent is high, this compound is in the same state as during the heat treatment of the silver ink composition to be described later. It is presumed that the formation of metallic silver may be started in at least a part of the material for forming metallic silver. Such a silver ink composition containing metallic silver may be able to form a conductor by performing post-treatment under milder conditions than a silver ink composition containing no metallic silver at the time of forming the conductor. In addition, even when the amount of the reducing agent is sufficiently large, the post-treatment may be similarly performed under mild conditions to form a conductor. As described above, by adopting the conditions that promote the decomposition of the forming material of metallic silver, the post-treatment can be performed by heating at a lower temperature, or by performing only drying at room temperature without performing the heating, to obtain a conductive material. May 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 the handling properties are not particularly poor.

  The drying treatment of the silver ink composition deposited (printed) on the substrate may be performed by a known method. For example, the drying may be performed under any of normal pressure, reduced pressure, and blowing conditions. It may be carried out either under an inert gas atmosphere. The drying temperature is not particularly limited, and may be either heating drying or room temperature drying. As a preferable drying method when the heat treatment is unnecessary, a method of drying at 18 to 30 ° C. in the atmosphere can be exemplified.

When the silver ink composition deposited on the substrate is subjected to a heating (firing) treatment, the conditions may be appropriately adjusted according to the types of the components of the silver ink composition. Usually, the heating temperature is preferably from 60 to 200 ° C, more preferably from 70 to 180 ° C. The heating time may be adjusted according to the heating temperature, but is usually preferably from 0.2 to 12 hours, more preferably from 0.4 to 10 hours. Among the materials for forming metallic silver, the silver carboxylate, particularly silver β-ketocarboxylate (1) is different from a material for forming metallic silver such as silver oxide, for example, using a reducing agent known in the art. Decomposes at low temperatures, if not present. 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.
When the silver ink composition is attached to a substrate having low heat resistance and is subjected to a heating (firing) treatment, the heating temperature is preferably lower than 130 ° C, more preferably 125 ° C or lower, and more preferably 120 ° C. It is particularly preferred that:

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

  In this specification, "humidification" means that the humidity is artificially increased unless otherwise specified, and preferably, the relative humidity is 5% or more. At the time of the heat treatment, the relative humidity of 5% is apparently artificially increased since the humidity in the processing environment becomes extremely low due to the high processing temperature.

  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, still more preferably 50% or more, and 70% or more. It is particularly preferred that the ratio be at least 90% or 100%. The heat treatment under humidification conditions may be performed by spraying high-pressure steam heated to 100 ° C. or higher. By performing the heat treatment under the humidifying condition in this way, higher purity metallic silver can be formed in a short time.

The heat treatment of the silver ink composition may be performed in two stages. For example, a method in which, in the first stage heat treatment, the silver ink composition is mainly dried instead of forming the metallic silver, and in the second stage heat treatment, the metallic silver is completely formed is exemplified.
In the first stage heat treatment, the heating temperature may be appropriately adjusted depending on the type of the components of the silver ink composition, but is preferably 60 to 120 ° C, more preferably 70 to 100 ° C. preferable. The heating time may be adjusted according to the heating temperature, but is usually preferably 5 seconds to 12 hours, and more preferably 30 seconds to 2 hours.
In the second stage of the heat treatment, the heating temperature may be appropriately adjusted according to the type of the components of the silver ink composition so that the metallic silver is favorably formed, but may be 60 to 200 ° C. The temperature is more preferably 70 to 180 ° C. The heating time may be adjusted according to the heating temperature, but is usually preferably 1 minute to 12 hours, more preferably 1 minute to 10 hours.
When the silver ink composition is attached to a substrate having low heat resistance and subjected to heating (firing) treatment, the heating temperature in the first and second heating treatments is preferably lower than 130 ° C. The temperature is more preferably 125 ° C or lower, and particularly preferably 120 ° C or lower.

Although the heat treatment of the silver ink composition described so far is performed in a gas phase, when the heat treatment of the silver ink composition is performed in two steps, the heat treatment in the second step is performed in a gas phase. The reaction may be performed in the liquid phase instead of in the liquid phase. The silver ink composition that has been completely or partially dried after the first-stage heat treatment can be subjected to the second-stage heat treatment by contacting the silver ink composition with the heated liquid without losing its shape. 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 a 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-stage heat treatment described above.
The above-mentioned heated liquid is preferably hot water (heated water), and the second heat treatment is performed by immersing the silver ink composition subjected to the first heat treatment in hot water, that is, It is preferred to do so.
When the second stage heat treatment is performed in a liquid phase, the metallic silver formed by this heat treatment may be further dried.

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

  When the heat treatment under the humidifying condition is adopted, the heat treatment of the silver ink composition is performed in the first stage heat treatment under the non-humidifying condition, not the formation of the metallic silver as described above but the formation of the silver ink composition. It is particularly preferable to carry out drying in a two-stage method, in which the second stage of the heat treatment is carried out in the second stage under humid conditions, in which the formation of metallic silver is completed as described above.

When performing the second stage heat treatment under humidification conditions, the heating temperature during the first stage non-humidification heat treatment is preferably 60 to 120 ° C, and is preferably 70 to 100 ° C. More preferred. The heating time is preferably from 5 seconds to 1 hour, more preferably from 30 seconds to 30 minutes, and particularly preferably from 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 is 70 to 130 ° C. Is more preferred. Further, 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.
When the silver ink composition is adhered to a substrate having low heat resistance and subjected to heating (firing) treatment, the heat treatment under non-humidifying conditions in the first stage and the heat treatment under humidifying conditions in the second stage are performed. The heating temperature is preferably lower than 130 ° C., more preferably 125 ° C. or lower, and particularly preferably 120 ° C. or lower.

  When manufacturing a wiring board according to the present invention having a structure other than silver fine wires on a substrate, in the above manufacturing method, a step of forming other structures at a predetermined timing is appropriately added. Just do it.

<< Electronic Equipment, Data Receiver / Transmitter, Transparent Conductive Film >>
The wiring board formed using the metal ink composition of the present invention is suitable for forming various electronic devices such as a data transmitter / receiver, a transparent conductive film, and the like.
For example, the electronic device can be configured to include the base material as a housing (exterior material) using the wiring board, and to configure at least a part of the housing (exterior material) with the base material in the wiring board. Except for the point described above, the configuration can be the same as that of a known electronic device. For example, a flat or curved surface portion of an exterior material in an electronic device such as a mobile phone is used as the base material, and the thin metal wire is formed directly on the exterior material (base material). A wiring board 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, operation switches, a display unit, and the like with the wiring board. Further, by using the patterned thin metal wire as an antenna, the wiring board can be used as an antenna structure.
The data receiver / transmitter can be configured to include the thin metal wire as an antenna using the wiring board, and have the same configuration as a known data receiver / transmitter except that the wiring board is used as an antenna structure. can do. For example, in the wiring board, a non-contact data transmitter / receiver can be configured by providing an IC chip electrically connected to the thin metal wires on a base material to form an antenna unit.

The transparent conductive film, using the wiring board, can be configured to be provided with the fine metal wires as ultra fine wiring or ultra thin wiring, except that the metal fine wires are provided as ultra fine wiring or ultra thin wiring, A structure similar to that of the transparent conductive film can be used. For example, a touch panel or an optical display can be configured by combining with a transparent substrate or the like in addition to the wiring board.
The thickness of the ultra-thin wiring is preferably 5 nm to 10 μm, more preferably 7 nm to 5 μm, and particularly preferably 10 nm to 1 μm.

Further, in the wiring board, the fine metal wires can be formed at a low temperature, and a wide range of materials such as a base material can be selected. Etc. can be a more rational structure.
The above electronic devices, transparent conductive films, and the like can maintain high performance over 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.

<Examples 1-2: Production of silver ink composition 1>
In a beaker, 2-ethylhexylamine (1.3 times molar amount with respect to silver 2-methylacetoacetate described later) and isobutylamine (0.2 times molar amount with respect to silver 2-methylacetoacetate described later) are mixed. It mixed and stirred for 1 minute using the mechanical stirrer. Here, 52.9 g of silver 2-methylacetoacetate, formic acid (0.4-fold molar amount based on silver 2-methylacetoacetate), 3,5-dimethyl-1 so that the liquid temperature is 25 ° C. or lower. -Hexin-3-ol ("Surfinol 61" manufactured by Air Products Japan, hereinafter may be abbreviated as "DMHO") (0.04 molar amount to silver 2-methylacetoacetate) in this order And stirred for 2 hours using a mechanical stirrer. Thus, a metal ink composition 1 was obtained.

<Reference Example 1: Production of silver ink composition 2>
In a beaker, 2-ethylhexylamine (0.7-fold molar amount with respect to silver 2-methylacetoacetate described later) and isobutylamine (0.3-fold molar amount with respect to silver 2-methylacetoacetate described later) are mixed. It mixed and stirred for 1 minute using the mechanical stirrer. Here, 52.9 g of silver 2-methylacetoacetate and formic acid (0.6-fold molar amount with respect to silver 2-methylacetoacetate) were added and mixed so that the liquid temperature would be 25 ° C. or lower, and then mechanically added. The mixture was stirred for 2 hours using a stirrer. Thereby, a first ink was obtained.
In a beaker, 2-ethylhexylamine (2.24 molar amount based on silver 2-methylacetoacetate described later) and DMHO (0.1 molar amount based on silver 2-methylacetoacetate described later) are mixed. Then, the mixture was stirred for 1 minute using a mechanical stirrer. Here, 1 mol of silver 2-methylacetoacetate was added and mixed so that the liquid temperature would be 5 ° C. or lower, and the mixture was stirred for 30 minutes using a mechanical stirrer. Thus, a second ink was obtained.
55 parts by mass of the first ink and 45 parts by mass of the second ink were mixed to obtain a silver ink composition 2.

Example 3 Production of Silver Ink Composition 3
52.9 g of silver 2-methylacetoacetate and hexane (1.63 times the molar amount of silver 2-methylacetoacetate) were placed in a beaker, and the mixture was stirred for 1 minute using a mechanical stirrer. To this, 2-ethylhexylamine (1.45 times the molar amount based on silver 2-methylacetoacetate) was added, and then formic acid (0.5 times the molar amount based on silver 2-methylacetoacetate) was added for 10 minutes. After stirring, stirring was continued for 1.5 hours, and then DMHO (0.032-fold molar amount based on silver 2-methylacetoacetate) and 4-ethyl-1-octin-3-ol (2- (A molar amount of 0.004 times the amount of silver methyl acetoacetate) was added and mixed, and the mixture was further stirred for 5 minutes. Thus, a silver ink composition 3 was obtained.

Example 4 Production of Silver Ink Composition 4
52.9 g of silver 2-methylacetoacetate and hexane (1.63 times the molar amount of silver 2-methylacetoacetate) were placed in a beaker, and the mixture was stirred for 1 minute using a mechanical stirrer. To this, 2-ethylhexylamine (1.45 times the molar amount based on silver 2-methylacetoacetate) was added, and then formic acid (0.5 times the molar amount based on silver 2-methylacetoacetate) was added for 10 minutes. After stirring, the mixture was stirred for 1.5 hours, then DMHO (0.024-fold molar amount based on silver 2-methylacetoacetate) and 4-ethyl-1-octin-3-ol (2- (A molar amount of 0.012 times the amount of silver methyl acetoacetate) was added and mixed, and the mixture was further stirred for 5 minutes. Thus, a silver ink composition 4 was obtained.

<Example 5: Production of silver ink composition 5>
52.9 g of silver 2-methylacetoacetate and hexane (1.63 times the molar amount of silver 2-methylacetoacetate) were placed in a beaker, and the mixture was stirred for 1 minute using a mechanical stirrer. Here, 2-ethylhexylamine (1.45-fold molar amount with respect to silver 2-methylacetoacetate) and formic acid (0.5-fold molar amount with respect to silver 2-methylacetoacetate) were added dropwise over 10 minutes. Thereafter, stirring was continued for 1.5 hours, and then DMHO (0.036-fold molar amount based on silver 2-methylacetoacetate) was added and mixed, followed by stirring for further 5 minutes. Thus, a silver ink composition 5 was obtained.

<Manufacture of wiring boards>
Using the silver ink composition obtained above by gravure offset printing, printing was performed on one main surface (front surface) of a polycarbonate substrate (thickness: 1 mm). A print pattern was formed.
In Examples 1 and 2, the silver ink composition 1 was used, and as Reference Example 1, the silver ink composition 2 was used. As Comparative Example 1, a commercially available silver paste (silver ink “TEC-PA-010” (manufactured by Inktec, silver content 55% by mass)) was used.
In Examples 3 to 5, the above silver ink compositions 3 to 5 were used.
More specifically, it is as follows.
The following was used as the printing device. That is, as the intaglio, a metal plate having a groove width of 4 μm and a groove depth of 10 μm, which is a silver fine wire pattern on its surface, was used. As the offset roll, a roll in which the surface of a metal cylinder was covered with a blanket material made of silicone resin was used.
Using such a printing apparatus, the silver ink composition is supplied to the intaglio plate, excess silver ink composition is removed by a doctor blade, and the silver ink composition filled in the groove is used as a blanket material for an offset roll. After the transfer to the surface of the substrate, printing was performed with the silver ink composition on the surface of the substrate transported by the belt conveyor unit.
The removal speed by the doctor blade is described in Table 1 as "doctor speed (mm / s)". Further, the amount of surface transfer of the blanket material is described in Table 1 as “blank indentation amount (μm)”.
Next, the obtained printed pattern was dried at 100 ° C. for 10 minutes, and further, the substrate was placed in a steam atmosphere at 100 ° C. and 100% relative humidity for 10 minutes to perform a heating (firing) treatment to obtain a wiring board.

<Evaluation of wiring board>
[Width and aspect ratio of fine silver wire]
About the obtained wiring board, the width and height of the fine silver wire were measured using the shape measurement laser microscope ("VKX-100" made by Keyence Corporation). The measurement was performed at nine places of the silver wiring, and the average value was calculated. The results are shown in Table 1 as “line width (μm)”.
Further, in the cross section of the obtained wiring board, the ratio of the height H to the width W (H / W), that is, the aspect ratio, was calculated. The results are shown in Table 1 as “aspect ratio”.

[Surface roughness]
The surface roughness is based on JIS B0601: 2001 (ISO4287: 1997), which means arithmetic average roughness (Ra), and only a reference length 1 is extracted from a roughness curve in the direction of the average line. When the X axis is taken in the direction of the average line of the sampled portion and the Y axis is taken in the direction of the vertical magnification, and the roughness curve is represented by y = Z (x), the value obtained by the following equation (II) is obtained. It is displayed in units of micrometers (μm). The results are shown in Table 1 as “surface roughness (Ra) (μm)”.

[Volume resistivity]
Further, with respect to the obtained wiring board, the wire resistance R (Ω), the cross-sectional area A (cm ² ), and the wire length L (cm) of the fine silver wire were measured, and according to the equation “ρ = R × A / L”. And volume resistivity ρ (Ω · cm) were calculated. The wire resistance R is measured using a digital multimeter (“PC5000a” manufactured by Sanwa Electric Instruments Co., Ltd.), and the cross-sectional area A is measured using a shape measuring laser microscope (“VK-X100” manufactured by Keyence Corporation). did. The results are shown in Table 1 as “volume resistivity (μΩ · cm)”.
In Comparative Example 1, the thin silver wire was broken, and the volume resistivity could not be measured.

  INDUSTRIAL APPLICATION This invention can be utilized for members in various electronic devices, such as an electromagnetic wave shield and a touch panel.

DESCRIPTION OF SYMBOLS 1 Wiring board 11 Substrate 11a Surface of substrate (one main surface)
12 Silver wire W Silver wire width H Silver wire height P Silver wire pitch

Claims (2)

With silver fine lines formed by printing method on the substrate,
The silver wire is
In a cross section perpendicular to the line length direction, the width is 20 μm or less, the aspect ratio is 0.013 or more and 0.025 or less,
Summit has become smaller in width than the contact portion with the substrate, the surface roughness of the silver thin line Ri der least 0.35μm below 0.25 [mu] m,
The silver fine line is formed using a silver ink composition,
The silver ink composition, beta-ketocarboxylic silver represented by the following general formula (1), a nitrogen-containing compound, and a reducing agent and Der Ru wiring board which either or both are blended alcohol.

(In the formula, R represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms which may be substituted with one or more hydrogen atoms or a phenyl group, a hydroxyl group, an amino group, or a compound represented by 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 - be a group represented by ";
Y ¹ is each independently a fluorine atom, chlorine atom, bromine atom or hydrogen atom; R ¹ is an aliphatic hydrocarbon group having 1 to 19 carbon atoms or a phenyl group; R ² is an aliphatic 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 is each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a phenyl group or a benzyl group in which one or more hydrogen atoms may be substituted with a substituent, a cyano group, - 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 ( ＯO) -O- ";
R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a thienyl group, or a phenyl group or a diphenyl group in which one or more hydrogen atoms may be substituted with a substituent. )     The wiring board according to claim 1, wherein the silver fine wire has a volume resistivity of 15 μΩ · cm or less.

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