JP5699447B2 - Conductive ink - Google Patents

Description

  The present invention relates to a conductive ink capable of forming a high-definition conductive circuit, and more particularly to a conductive ink for screen printing.

In general, an etching method and a printing method are known as an electronic component, a thin film forming unit for electromagnetic wave shielding, or a conductive circuit forming unit.
The etching method means a processing technique in a broad sense including a surface treatment of a metal by dissolving or removing the surface or shape of the metal chemically or electrochemically. Etching is a kind of chemical processing, and is mainly performed to obtain a desired pattern shape on the metal surface. However, the process is generally complicated, and waste liquid treatment is required in the subsequent process, so the cost is low. There are many problems. Moreover, since the conductive circuit formed by the etching method is formed only of a metal such as aluminum or copper, there is a problem that it is weak against physical impact such as bending.

Therefore, in order to solve these problems and form a conductive circuit at a lower cost, a conductive film containing fine metal fine particles and a binder such as a resin is directly applied to the polyamide film by a printing method such as screen printing, A printing method has been proposed in which a conductive circuit is formed by printing on the surface of a substrate such as a PET film, ceramic, or glass (see, for example, Patent Document 1: Japanese Patent Laid-Open No. 06-68924).
These conductive inks can be expected to reduce the size and weight of electronic components, improve productivity, and reduce costs, and can easily form a conductive circuit by printing or coating on a substrate and drying. Furthermore, in this drying and curing process, demand can be rapidly increased in recent years because it can be performed at a low temperature without applying a high temperature to the substrate or the electronic component.

  However, in recent high-definition of conductive circuit patterns, circuit wiring obtained by actually printing even if a high-definition pattern such as a line width of a circuit wiring itself or a width between wirings of 100 μm or less is formed. The line width is often larger than the target line width, so adjacent wires are too close or in contact with each other, or the edges of the wires bleed, making the boundary line unclear, and a good conductive circuit There is a problem that cannot be formed. More recently, with the miniaturization of mobile terminals such as mobile phones and game machines, the introduction of touch screen panels, etc., the definition of conductive circuit patterns has been further advanced, and the line width of the circuit wiring itself and the width between wiring lines are 50 μm. The following high definition is also required.

By the way, the screen printing method is a method in which printing ink is printed through the meshes of the openings of the screen printing plate while placing the printing ink on the screen printing plate and pressing it with a squeegee or the like. In other words, the screen printing method is a method of bending and printing the screen printing plate by pressing with a squeegee or the like, and is therefore unsuitable for applications and fields that require high-definition printing accuracy.
However, in other printing methods, it is the limit to form a conductive circuit with a thickness of about 1 to 2 μm, and in order to form a conductive circuit with a resistance as low as possible, a thickness of several μm or more must be secured. Is required. A screen printing method is suitable for printing such a thick film.

By the way, the conductive ink is generally heavy because it contains a large amount of conductive particles having a heavy specific gravity, and compared to a general printing ink, the conductive ink is passed through the opening of the screen plate, and transferred to the substrate. Before drying and solidifying, it tends to flow and spread outside the printing area due to its own weight and the like. As a result, it is often larger than the line width of the target circuit wiring, so that adjacent wirings are too close or in contact with each other, or the edge of the wiring bleeds and the boundary line becomes unclear and good. There was a problem that a conductive circuit could not be formed.

Such a problem becomes conspicuous when forming a high-definition pattern in which the line width of the circuit wiring itself and the width between the wirings are 100 μm or less.
In order to print a high-definition circuit pattern, it is necessary to use a fine screen mesh. In order to use a fine screen mesh, it is preferable to use conductive particles having a particle size as small as possible. However, conductive particles with a small particle size are more likely to flow on the movement of the solvent and binder resin contained in the conductive ink being dried and solidified after printing, compared to those with a large particle system. The “thickening” phenomenon of the line width that protrudes outside the region is likely to occur.

  For such a problem, Patent Document 2: WO2003 / 103352 discloses a conductive ink containing spherical or granular metal particles having a specific average particle size and a maximum particle size with respect to a substrate having a roughened surface. A technique for forming a high-definition conductive circuit by printing using a printer is disclosed. However, the technique disclosed in Patent Document 2 requires a surface roughening step of the base material in order to form a high-definition conductive circuit, and there is a problem that the manufacturing cost increases due to an increase in the number of steps.

By the way, in order to perform screen printing with high accuracy, various printing conditions such as screen mesh and emulsion thickness are set as appropriate, and the substrate is appropriately selected as described above. Many studies have been made.
The amount of ink transferred to the substrate greatly depends on the amount of ink passing through the screen opening, and when the amount of passage increases, the fine line portion tends to bleed and become thicker. When the ink viscosity is too low, the amount of passage increases, and when the ink viscosity is too low, the ink adheres to the back surface around the opening of the screen plate when passing the ink through the opening of the screen plate. In this case, there is a problem that printing with high accuracy cannot be performed.
Therefore, a method of increasing the ink viscosity has been taken in order to suppress the ink passing amount. However, only by increasing the viscosity, it becomes difficult to sufficiently pass the ink from the opening of the screen plate, and high-precision printing cannot be performed. In particular, in continuous printing, fine lines are drawn or breakage is likely to occur.
Therefore, in order to perform high-accuracy screen printing, it has a so-called thixotropic property that reduces the viscosity when an external force is applied by a squeegee or the like, but maintains a high viscosity when no external force is applied. It has been generally said that it is necessary.

The conventional way of thinking about the relationship between screen printing and thixotropy of printing ink will be explained.
Considering the printing behavior of screen printing ink, the printing ink moves on the screen printing plate while rotating by a squeegee called rolling, fills the screen with a predetermined pattern, and opens the base material through the opening. Supplied above and transferred to the substrate. The viscosity at the time of ink filling / transition is regarded as corresponding to the viscosity at high speed rotation by a rotational viscometer. Moreover, it becomes a stationary state when the external force is no longer applied. The viscosity in the stationary state is regarded as corresponding to the viscosity at a low speed rotation by a rotational viscometer.
Therefore, as a screen printing ink capable of forming a high-definition print pattern, it exhibits a lower viscosity at the time of filling and transfer, and when it is transferred to the base material, it rapidly increases in viscosity and is printed on the base material. It has been considered necessary to maintain the desired shape.

That is, using a rotational viscometer (divided into a double cylinder type, a cone-disk type, a parallel disk type, etc. depending on the shape of the measuring part), the viscosity is measured at different rotational speeds, When plotting the relationship in a logarithmic graph, the line connecting the plots becomes a straight line having a certain slope, or screen printing ink that exhibits a state close to it may form a high-definition print pattern. It has been considered a possible screen printing ink.
For example, Japanese Patent Application Laid-Open No. 2003-238876 discloses a screen printing ink for forming a high-definition color filter by controlling the TI value.
In the rotational viscometer, there is no absolute index as to whether the viscosity at any number of rotations corresponds to the viscosity at the above-described high-speed rotation or low-speed rotation, but n rotation (low-speed rotation) In general, the ratio of the viscosity at the time of high speed rotation to the viscosity at the time of low speed rotation is determined and evaluated as a TI value (thixo index, thixo index).

The same applies to the conductive ink. Viscosity = shear stress (Pa) when an arbitrary rotational speed = shear rate (/ sec) is measured (so-called static steady flow measurement), and further different rotational speeds = different shear rates. In many cases, viscosity = shear stress (Pa) is obtained, and thixotropy is evaluated from the relationship between the two viscosities.
For example, Patent Document 4: Japanese Patent Laid-Open No. 2001-234106 discloses a conductive ink that is not for screen printing but for lithographic offset printing, and defines and specifies shear stress for a specific shear rate. Evaluation / examination of the ratio (so-called TI value) of the shear rate stress at two points is disclosed.

In general, printable inks containing polymer materials such as synthetic resins have properties (viscoelasticity) that have elastic properties (elastic deformation) simultaneously with flow (viscous flow), but compared with elastic behavior. Since the ratio of the viscous behavior is high, the viscous behavior is often grasped at a certain rotational speed, that is, a steady flow as described above.
However, the viscosity measured in a steady flow changes greatly with time, and reproducible data is often not obtained. From the data such as the TI value of a rotary viscometer, the actual fluidity (viscosity of ink) Flow) and printability is difficult to evaluate.
In particular, when high-definition printing such as a line width of 50 μm is required, it is not sufficient to simply grasp and control viscous flow.
Japanese Patent Application Laid-Open No. 06-68924 WO2003 / 103352 brochure JP 2003-238876 A JP 2001-234106 A

  An object of this invention is to provide the conductive ink for screen printing which can form a highly fine conductive circuit pattern.

The present invention
Tap density is 1.0-10.0 (g / cm ³ ), D50 particle size is 0.3-5 μm, BET
Conductive particles having a specific surface area of 0.3 to 5.0 m ² / g;
A binder resin having a number average molecular weight (Mn) of 10,000 to 300,000, a hydroxyl value of 2 to 300 (mgKOH / g) and / or an acid value of 20 (mgKOH / g) or less;
A conductive ink containing a metal chelate having a storage elastic modulus G ′ of 5000 to 50,000 (Pa) at 25 ° C., a frequency of 1 (Hz), and a vibration stress of 50 (pa), and a loss elastic modulus G ′. A value obtained by dividing 'by storage elastic modulus G', tanδ is 1 or less, and a conductive ink,
The conductive particles preferably have a tap density of 2.0 to 10.0 (g / cm ³ ).

The conductive ink of the invention preferably contains 0.2 to 20 parts by weight of a metal chelate with respect to 100 parts by weight of the binder resin,
The metal chelate is preferably an aluminum chelate,
The aluminum chelate preferably has a group selected from the group consisting of an acetylacetonate group, a methylacetoacetonate group, and an ethylacetoacetonate group.

  In any one of the inventions, the conductive particles are preferably silver.

Furthermore, in any one of the above inventions, the binder resin is preferably at least one selected from polyester resins, polyurethane resins, polyurethane urea resins, epoxy resins, and acrylic resins,
Further, it is preferable to further contain a curing agent having a functional group capable of reacting with the functional group of the binder resin,
The curing agent is preferably at least one selected from the group consisting of isocyanate compounds, epoxy resins, aziridine compounds, oxazoline compounds, amine compounds, and acid anhydrides,
The curing agent is preferably contained in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin.
The conductive ink of any one of the inventions is suitably used for screen printing.

  With the conductive ink of the present invention, a high-definition conductive circuit pattern can be formed by screen printing.

Embodiments of the present invention will be described below.
The conductive ink of the present invention has a tap density of 1.0 to 10.0 (g / cm ³ ), a D50 particle size of 0.3 to 5 μm, and a BET specific surface area of 0.3 to 5.0 m ² / g. Containing particles, a binder resin having a number average molecular weight (Mn) of 10,000 to 300,000, a hydroxyl value of 2 to 300 (mgKOH / g) and / or an acid value of 20 (mgKOH / g) or less, and a metal chelate The storage elastic modulus G ′ is 5000 to 50,000 (Pa) at 25 ° C., frequency 1 (Hz), and vibration stress 50 (pa), and the loss elastic modulus G ″ is stored as the storage elastic modulus G. Value divided by ', tanδ is 1
It becomes the following.

The conductive ink of the present invention has a storage elastic modulus G ′ of 5,000 to 50,000 (Pa) at 25 ° C., a frequency of 1 (Hz), and a vibration stress of 50 (pa), and has a loss elastic modulus G ″. The value obtained by dividing the storage elastic modulus G ′, tan δ, must be 1 or less in order to impart high-definition pattern printability. The storage elastic modulus G ′ is 6,000 to 20,000 (Pa). Preferably tan δ
Is preferably 0.5 to 0.9.

When the storage elastic modulus G ′ at 25 ° C., frequency 1 (Hz), and vibration stress 50 (pa) is less than 5,000 Pa, the elasticity is weak, and the ink passes through the opening of the screen and is transferred to the substrate. It becomes difficult to maintain the shape of the pattern, and the printability of a high-definition pattern is poor.
On the other hand, when the storage elastic modulus G ′ of the conductive ink exceeds 50,000 pa, the elasticity becomes too strong, the ink cannot be rolled on the screen printing plate, and it is difficult to fill a predetermined pattern provided on the screen. Therefore, screen printing is not possible.
On the other hand, if the tan δ of the conductive ink exceeds 1, the elastic properties are reduced and the printability of the high-definition pattern tends to be poor.

As described in the background section, the conventional conductive ink controls the passing amount only by viscous flow (so-called viscosity), and a method of increasing the viscosity is taken to suppress the passing amount. . However, if the viscosity is simply increased, fine lines are drawn or breakage is likely to occur in continuous printing.
Moreover, in the steady flow measurement, even when using conductive ink imparted only with so-called thixotropy, the viscosity is high at a low shear rate and the viscosity is low at a high shear rate. It is difficult to print a pattern (for example, a line width or a width between wirings of 50 μm).
Therefore, the conductive ink of the present invention has increased elastic properties and the amount of ink passing is controlled, and has a remarkable effect in printing a high-definition pattern (for example, a line width or a width between wirings of 50 μm). There is.

  There are various methods for evaluating the viscoelastic behavior of conductive ink, but the measurement method with fixed sine vibration frequency and changing vibration stress measures the dynamic viscoelasticity of dispersed systems such as conductive ink. Is preferred.

  The conductive ink that exhibits viscoelastic behavior as described above contains specific conductive particles, a specific binder resin, and a metal chelate.

  Examples of the conductive particles used in the conductive ink of the present invention include gold, silver, copper, silver-plated copper powder, silver-copper composite powder, silver-copper alloy, amorphous copper, nickel, chromium, palladium, rhodium, ruthenium, Metal powder such as indium, silicon, aluminum, tungsten, morphbutene, platinum, inorganic powder coated with these metals, powder of metal oxide such as silver oxide, indium oxide, tin oxide, zinc oxide, ruthenium oxide, these Inorganic powders coated with metal oxides, carbon black, graphite and the like can be used. These conductive particles may be used alone or in combination of two or more. Among these conductive particles, silver is preferable because of its cost, high conductivity, and little increase in resistivity due to oxidation.

The shape of the conductive particles may be various, such as irregular, aggregated, scale-like, microcrystalline, spherical, and flake-like, but from the viewpoint of the printability of the high-definition pattern that is the object of the present invention. Spherical ones having a small particle diameter are preferred. As described above, such conductive particles have a tap density of 1.0 to 10.0 (g / cm ³ ), preferably 2.0 to 10.0 (g / cm ³ ), and more preferably. Is in the range of 3.0 to 6.0 (g / cm ³ ).
Further, the D50 particle diameter of the conductive particles is 0.3 to 5 μm, and preferably in the range of 0.3 to 1.2 μm. Further, the BET specific surface area is 0.3 to 5.0 m ² / g, preferably 0.8 to 2.3 m ² / g.

When the tap density of the conductive particles is less than 1 (g / cm ³ ), the conductive particles become bulky and the gaps between the conductive particles become large, so that the contact point between the conductive particles is reduced, and the printed matter The volume resistivity increases. Moreover, the dispersibility when using conductive ink is poor, and the printability of a high-definition pattern is poor.
On the other hand, when the tap density exceeds 10.0 (g / cm 3), the cost of the conductive particles increases,
The manufacturing cost of the high-definition conductive circuit is increased. In addition, when the conductive ink is used, the conductive particles are easily precipitated over time.

  The tap density in the present invention refers to the weight per volume after a certain amount of powder is placed in a certain container while being vibrated up and down. The larger this value is, the larger the packing density becomes, and the contact point between the particles becomes larger when conductive particles are obtained, so that good conductivity can be obtained. However, in the present invention, the conductivity with a dap density of 10.0 or less is obtained. It is appropriate to use sex particles. The tap density was measured based on the JIS Z 2512: 2006 method.

If the D50 particle diameter of the conductive particles is less than 0.1 μm, the dispersibility of the conductive particles deteriorates when the conductive ink is used, resulting in poor contact between the conductive particles, resulting in a large printed resistance value. And the cost of the conductive particles is high.
On the other hand, if the d50 particle diameter exceeds 5 μm, the printability of the high-definition pattern may be inferior.
The D50 particle size of the conductive particles was determined by measuring the cumulative particle size (D50) of the volume particle size distribution measured using a laser diffraction particle size distribution measuring device “SALAD-3000” manufactured by Shimadzu Corporation.

When the BET specific surface area of the conductive particles is less than 0.3 m ² / g, the contact point between the conductive particles decreases, and the contact resistance increases.
In addition, if the BET specific surface area exceeds 5.0 m ² / g, a large amount of resin is required to coat the surface of the conductive particles, so that wetting with respect to the binder resin is inferior, and the fluidity when the conductive ink is used. Is worse, and the leveling property of the surface of the printed coating is reduced, which is not preferable. In addition, since a large amount of resin is required to coat the surface of the conductive particles, the ink adhesion also decreases.
The BET specific surface area is a method of adsorbing molecules with a known adsorption area on the powder particle surface at the temperature of liquid nitrogen, and obtaining the specific surface area of the sample from the amount, using low-temperature low-humidity physical adsorption of inert gas This is the BET method. The BET specific surface area is described by defining a value calculated by the following calculation formula from the surface area measured using a flow type specific surface area measuring device “Flowsorb II” manufactured by Shimadzu Corporation as a specific surface area.
Specific surface area (m ² / g) = surface area (m ² ) / powder mass (g)

The binder resin used in the present invention has a number average molecular weight (Mn) of 10,000 to 300,000, preferably 20,000 to 100,000. The hydroxyl value is 2 to 300 (mg KOH / g) and / or the acid value is 20 (mg KOH / g) or less, preferably the hydroxyl value is 5 to 200 (mg KOH / g) and / or the acid value is 10 (mg KOH / g). It is as follows.
Here, the hydroxyl group and the carboxyl group react with a metal chelate described later to give the rheological characteristics necessary for the printability of the high-definition pattern in the screen printing method, and further a functional group that reacts when a curing agent is used. As necessary. The binder resin may have both a hydroxyl group and a carboxyl group, or may have either one.

When the number average molecular weight (Mn) of the binder resin is less than 10,000, a sufficient storage elastic modulus G ′ cannot be obtained, and when it exceeds 300,000, the storage elastic modulus G ′ becomes too high and screen printing becomes impossible. .
Further, if the hydroxyl group is less than 2 (mgKOH / g), sufficient storage modulus G ′ cannot be obtained, and if the hydroxyl value exceeds 200 (mgKOH / g) or the acid value exceeds 20 (mgKOH / g). The storage elastic modulus G ′ becomes too high, and screen printing becomes impossible.

Examples of such binder resins include polyester resins, urethane-modified polyester resins, epoxy-modified polyester resins, acrylic resins, styrene resins, epoxy resins, modified epoxy resins, vinyl chloride-vinyl acetate copolymers, butyral resins, acetal resins, phenol resins, Polyurethane resin, polyurethane urea resin, polyamide resin, polyimide resin, polyamideimide resin, alkyd resin, polyolefin resin, fluorine resin, ketone resin, benzoguanamine resin, melamine resin, urea resin, silicone resin, nitrocellulose, cellulose acetate butyrate ( One or more selected from CAB) resin, cellulose acetate propionate (CAP) resin, rosin, rosin ester, maleic resin, etc. Resins can be used in combination depending on the type of method, the type of printing substrate, the printing conditions, and the application of the circuit.

  In particular, the binder resin used in the present invention includes adhesion to a substrate, solubility in a solvent used in screen printing, mechanical strength necessary for a conductive ink coating necessary for forming a conductive circuit, etc. More preferred are polyester resins, polyurethane resins, polyurethane urea resins, epoxy resins and acrylic resins.

As the polyester resin used for the binder resin used in the present invention, those containing a hydroxyl group and / or a carboxyl group in the polyester resin skeleton and having a number average molecular weight of 10,000 to 300,000 can be used.
These polyester resins can be obtained by copolymerization by a known method under normal pressure or reduced pressure. The polyester resin is preferably a saturated polyester. In addition, after polymerizing the polyester resin, a cyclic ester such as ε-caprolactone is post-added (ring-opening addition) at 180 to 230 ° C. to form a block, or an acid anhydride such as trimellitic anhydride or phthalic anhydride is post-added. Then, an acid value may be imparted.

  Examples of the dicarboxylic acid used in the polyester resin include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and 2,6-naphthalenedicarboxylic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, Aliphatic dicarboxylic acids such as azelaic acid, dibasic acids having 12 to 28 carbon atoms, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methylhexahydrophthalic anhydride Acid, 3-methylhexahydrophthalic anhydride, 2-methylhexahydrophthalic anhydride, dicarbonoxy hydrogenated bisphenol A, dicarbonoxy hydrogenated bisphenol S, dimer acid, hydrogenated dimer acid, hydrogenated naphthalenedicarboxylic acid, tricyclo Candika Alicyclic dicarboxylic acids such as carbon acid, hydroxybenzoic acid, and hydroxycarboxylic acids such as lactic acid is. Further, polycarboxylic acids such as trimellitic anhydride and pyromellitic anhydride, unsaturated dicarboxylic acids such as fumaric acid, dicarboxylic acids containing sulfonic acid metal salts such as sodium 5-sulfoisophthalic acid, etc. may be used in combination. .

  Examples of the alkylene glycol used in the polyester resin include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3 -Methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, , 9-nonanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, dimer diol and the like. Moreover, you may use together polyhydric polyols, such as a tolmethylol propane, glycerol, a pentaerythritol, a polyglycerol.

The polyurethane resin and polyurethane urea resin used for the binder resin used in the present invention contain hydroxyl groups and / or carboxyl groups in the polyurethane resin and polyurethane urea resin skeleton, and have a number average molecular weight of 10,000 to 300,000. Can be used.
Moreover, as a polyurethane resin and a polyurethane urea resin, what was obtained by making a polyol compound and a chain extender react with an isocyanate compound as needed by a well-known method can be used. That is, as a polyurethane resin, a polyol compound, an organic diisocyanate, and a diol compound that is a chain extender are reacted to obtain a polyurethane resin in a state where a hydroxyl group is present at the terminal. Further, the polyurethane urea resin can be obtained by reacting a polyol compound and an organic isocyanate to form a urethane prepolymer having an isocyanate group, and further reacting a polyamino compound and, if necessary, a reaction terminator.

As the polyol compound, various polyether polyols, polyester polyols, polycarbonate polyols, polybutadiene glycols, or a mixture thereof, which are generally known as a polyol component constituting a polyurethane resin, can be used.

  Examples of polyether polyols include polymers or copolymers such as ethylene oxide, propylene oxide, and tetrahydrofuran.

  Polyester polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1, Saturated and unsaturated low-molecular diols such as 5-pentanediol, hexanediol, octanediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, dimer diol, and n-butyl glycidyl ether, 2 -Alkyl glycidyl ethers of ethylhexyl glycidyl ethers, monocarboxylic acid glycidyl esters such as versatic acid glycidyl ester, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid Polyester polyols obtained by dehydration condensation of dicarboxylic acids such as fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or the like, Examples include polyester polyols obtained by ring-opening polymerization of a cyclic ester compound.

As the polycarbonate polyol, 1) a reaction product of diol or bisphenol and a carbonic acid ester, and 2) a reaction product of diol or bisphenol with phosgene in the presence of an alkali can be used. Examples of the carbonate ester include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, and propylene carbonate. Examples of the diol include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, butylene glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 3,3. '-Dimethylol heptane, polyoxyethylene glycol, polyoxypropylene glycol, propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9 Nonanediol, neopentyl glycol, octanediol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, 3,9-bis (1,1-dimethyl-2-hydroxyethyl, 2,2 , 8, 10-tetraoxospiro [5.5
] Undecane etc. are mentioned. Examples of bisphenol include bisphenol A, bisphenol F, and bisphenols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to bisphenols.

  The number average molecular weight (Mn) of the polyol compound is appropriately determined in consideration of the heat resistance, mechanical properties, solubility, and the like of the obtained polyurethane resin or polyurethane polyurea resin, but usually in the range of 500 to 8000, More preferably, it is 1000-5000. When Mn is less than 500, the number of urethane bonds in the polyurethane resin or polyurethane polyurea resin increases too much, the flexibility of the polymer skeleton tends to decrease and the adhesion to the substrate tends to decrease, and Mn exceeds 8000. And the molecular weight between cross-linking points tends to increase and the heat resistance tends to decrease.

The above polyol compounds may be used alone or in combination of two or more. Furthermore, a part of the polyol compound may be replaced with low molecular diols, for example, various low molecular diols used in the production of the polyol compound, within the range in which the performance of the polyurethane resin or polyurethane polyurea resin is not lost. In particular, in polyester polyols, the toughness of polyurethane resins and polyurethane polyurea resins is improved by using terephthalic acid having an aromatic ring in the structure and a high content of isophthalic acid as the dicarboxylic acid component. Particularly preferred because the mechanical hardness of the film is improved

  As the diol compound that is a chain extender, saturated and unsaturated low molecular weight diols that are raw materials for the above-described alkylene glycols used in polyester resins, polyester polyols used in polyurethane resins and polyurethane urea resins are preferably used. It is done. Moreover, the diol compound which has a carboxyl group can also be used as a raw material at the time of introduce | transducing a carboxyl group into a urethane resin or a polyurethane urea resin frame | skeleton. Examples of the diol compound having a carboxyl group include dimethylol alkanoic acid such as dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, and dimethylolpentanoic acid, dihydroxysuccinic acid, and dihydroxybenzoic acid. In particular, dimethylolpropionic acid and dimethylolbutanoic acid are preferable from the viewpoint of reactivity and solubility.

  As the organic diisocyanate compound used for forming the polyurethane resin or polyurethane polyurea resin, aromatic diisocyanate, aliphatic diisocyanate, alicyclic isocyanate, or a mixture thereof can be used.

Aromatic diisocyanates include 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-benzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1 , 3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate and the like.
Examples of the aliphatic diisocyanate include butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.

  Examples of the alicyclic diisocyanate include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, norbornane diisocyanate methyl, bis (4-isocyanatocyclohexyl) methane, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, and the like. It is done.

  The conditions for obtaining a polyurethane resin having a hydroxyl group by reacting a polyol compound, an organic diisocyanate and a diol compound are not particularly limited except that the hydroxyl group is excessive, but the isocyanate group / hydroxyl group equivalent ratio is 0.8 / 1. It is preferable to be within the range of -0.99 / 1. The reaction is usually carried out at a temperature between normal temperature and 150 ° C., and is preferably carried out at a temperature between 60 ° C. and 140 ° C. from the viewpoint of production time and side reaction control.

  The polyurethane polyurea resin is obtained by reacting a urethane prepolymer having an isocyanate group with a polyamino compound. The urethane prepolymer having an isocyanate group is a hydroxyl group except that a diol compound having a carboxyl group is reacted under an isocyanate group-excess condition when a carboxyl group is introduced into a polyol compound, organic diisocyanate, or polyurethane urea resin skeleton. In the same manner as in the case of obtaining a polyurethane resin having, it can be obtained by a conventionally known method. The equivalent ratio of isocyanate group / hydroxyl group is preferably in the range of 1.05 / 1 to 3/1. More preferably, it is 1.2 / 1 to 2/1. The reaction is usually carried out at a temperature between normal temperature and 150 ° C., and is preferably carried out at a temperature between 60 ° C. and 140 ° C. from the viewpoint of production time and side reaction control. The number average molecular weight of the urethane prepolymer having an isocyanate group is preferably in the range of 2000 to 100,000.

The resulting urethane prepolymer having an isocyanate group is reacted with a polyamino compound to obtain a polyurethane polyurea resin. The polyamino compound functions as a chain extender, and examples thereof include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4′-diamine, and norbornanediamine. When introducing a hydroxyl group into the polyurethane urea resin skeleton, 2- (2-aminoethylamino) ethanol, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2 A chain of a polyamino compound having a hydroxyl group such as hydroxypropylethylenediamine can also be used.

  When a polyurethane preurea resin having an isocyanate group is reacted with a polyamino compound to synthesize a polyurethane polyurea resin, a reaction terminator can be used in combination to adjust the molecular weight of the resulting polyurethane polyurea resin. As the reaction terminator, dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol can be used. Moreover, when introducing a hydroxyl group into the terminal of the polyurethane urea resin skeleton, dialkanolamines such as diethanolamine can be used.

  The conditions for reacting the urethane prepolymer having an isocyanate group with the polyamino compound and, if necessary, the reaction terminator are not particularly limited, but the free isocyanate group at both ends of the urethane prepolymer is defined as 1 equivalent. In this case, the total equivalent of amino groups in the polyamino compound and the reaction terminator is preferably in the range of 0.5 to 1.3. More preferably, it is in the range of 0.8 to 0.995. When the total equivalent of amino groups is less than 0.5, the molecular weight of the polyurethane urea resin cannot be sufficiently increased. When the amount exceeds 1.3, the polyamino compound and the reaction terminator remain in a large amount unreacted, which may reduce the adhesion of the conductive ink.

When synthesizing polyurethane resins and polyurethane urea resins, one kind selected from ester solvents, ketone solvents, glycol ether solvents, aliphatic solvents, aromatic solvents, carbonate solvents is used alone or in combination of two or more. Can be used.
Examples of ester solvents include ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, and ethyl lactate. Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone benzene, diisobutyl ketone, diacetone alcohol, isophorone, and cyclohexanenone.
Examples of glycol ether solvents include ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, etc., acetates of these monoethers, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene Examples include glycol monomethyl ether, propylene glycol monoethyl ether, and the like, and acetates of these mono ethers.
Examples of the aliphatic solvent include n-heptane, n-hexane, cyclohexane, methylcyclohexane, and ethylcyclohexane.
Examples of the aromatic solvent include toluene and xylene.

The epoxy resin used for the binder resin used in the present invention is not particularly limited as long as it contains two or more epoxy groups and a hydroxyl group in one molecule and has a number average molecular weight of 10,000 to 1,000,000.
For example, polyglycidyl ether obtained by reaction of bisphenol A, bisphenol F, bisphenol S, bisphenol AD, novolak, cresol novolaks and epichlorohydrin is preferably used. A phenoxy resin which is a so-called polymer epoxy resin can also be used.

  The acrylic resin used in the binder resin used in the present invention is copolymerized with a unsaturated monomer containing a hydroxyl group and / or a carboxyl group and, if necessary, with another unsaturated monomer by a known method. What has a number average molecular weight of 10,000 to 300,000 can be used.

  Here, examples of the unsaturated monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,4-butanediol mono ( Examples include (meth) acrylate, caprolactone-modified hydroxy (meth) acrylate, (meth) acrylic acid ester of phenylglycidyl ether, and the like.

  Examples of the unsaturated monomer containing a carboxyl group include (meth) acrylic acid, itaconic acid, maleic anhydride, 2-carboxy-1-butene, 2-carboxy-1-pentene, and 2-carboxy-1. -Hexene, 2-carboxy-1-heptene and the like.

  Furthermore, as an unsaturated monomer which can be copolymerized with an unsaturated monomer containing a hydroxyl group and / or a carboxyl group as necessary, for example, an acidic phosphate ester such as 2- (meth) acryloyloxyethyl acid phosphate Unsaturated monomer; (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate Ester; Unsaturated monomer having epoxy group such as glycidyl (meth) acrylate, monomer having alicyclic epoxy machine; meth) acrylamide, N, N′-dimethylaminoethyl (meth) acrylate, N, N '-Diethylaminoethyl (meth) acrylate, N-phenylmaleimide Unsaturated monomers having nitrogen atoms such as N-cyclohexylmaleimide; ethylene glycol di (meth) acrylate, tritylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. An unsaturated monomer having two or more polymerizable double bonds; an unsaturated monomer having a halogen atom such as vinyl chloride; an aromatic unsaturated monomer such as styrene or α-methylstyrene; And vinyl esters.

Moreover, the unsaturated monomer containing a cycloalkyl group can also be used.
Examples of the unsaturated monomer containing a cycloalkyl group include monomers having one alicyclic structure such as a cyclohexyl group, a methylcyclohexyl group, an ethylcyclohexyl group, and a cyclododecyl group; a bornyl group, an isobornyl group, and a dicyclo group. And monomers having a plurality of alicyclic structures such as a pentenyl group, a dicyclopentanyl group, and an adamantane group.

For example, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tert-butylcyclohexyl methacrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy Ethyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, cyclohexylmethyl (meth) acrylate, cyclohexylethyl (meth) acrylate, cyclohexylpropyl (meth) acrylate, cyclohexylbutyl (meth) acrylate, 4-methylcyclohexyl Methyl (meth) acrylate, 4-ethylcyclohexylmethyl (meth) acrylate, 4-propylcyclohexyl Rumethyl (meth) acrylate, 4-butylcyclohexylmethyl (meth) acrylate, 4-methoxycyclohexylmethyl (meth) acrylate, 4-acetoxymethylcyclohexylmethyl (meth) acrylate, 3-methylcyclohexylmethyl (meth) acrylate, 3 -Ethylcyclohexylmethyl (meth) acrylate, 3-propylcyclohexylmethyl (meth) acrylate, 3-butylcyclohexylmethyl (meth) acrylate, 3-methoxycyclohexylmethyl (meth) acrylate, 3-acetoxymethylcyclohexylmethyl (meth) acrylate, 3-hydroxymethylcyclohexylmethyl (meth) acrylate, 4-methylcyclohexylethyl (meth) acrylate, 4-ethylcyclohexyl ether (Meth) acrylate, 4-propylcyclohexylethyl (meth) acrylate, 4-butylcyclohexylethyl (meth) acrylate, 4-methoxycyclohexylethyl (meth) acrylate, 4-acetoxymethylcyclohexylethyl (meth) acrylate, 4-hydroxy Methylcyclohexylethyl (meth) acrylate, 3-methylcyclohexylethyl (meth) acrylate, 3-ethylcyclohexylethyl (meth) acrylate, 3-propylcyclohexylethyl (meth) acrylate, 3-butylcyclohexylethyl (meth) acrylate, 3- Methoxycyclohexylethyl (meth) acrylate, 3-acetoxymethylcyclohexylethyl (meth) acrylate, 3-hydroxymethylcyclohexyl Ruethyl (meth) acrylate, 4-methyltylcyclohexylpropyl (meth) acrylate, 4-ethylcyclohexylpropyl (meth) acrylate, 4-methoxycyclohexylpropyl (meth) acrylate, 4-acetoxymethylcyclohexylpropyl (meth) acrylate, 4- Hydroxymethylcyclohexylpropyl (meth) acrylate, 3-methyltylcyclohexylpropyl (meth) acrylate, 3-ethylcyclohexylpropyl (meth) acrylate, 3-methoxycyclohexylpropyl (meth) acrylate, 3-acetoxymethylcyclohexylpropyl (meth) acrylate , 3-hydroxymethylcyclohexylpropyl (meth) acrylate, 4-methyltylcyclohexylbutyl (meth) a Relate, 4-ethylcyclohexylbutyl (meth) acrylate, 4-methoxycyclohexylbutyl (meth) acrylate, 4-acetoxymethylcyclohexylbutyl (meth) acrylate, 4-hydroxymethylcyclohexylbutyl (meth) acrylate, 3-methyltylcyclohexylbutyl (Meth) acrylate, 3-ethylcyclohexylbutyl (meth) acrylate, 3-methoxycyclohexylbutyl (meth) acrylate, 3-acetoxymethylcyclohexylbutyl (meth) acrylate, 3-hydroxymethylcyclohexylbutyl (meth) acrylate, 2-methyl -1-cyclohexylmethyl (meth) acrylate, 2,3-dimethyl-1-cyclohexylmethyl (meth) acrylate, 2,6-dimethyl 1-cyclohexylmethyl (meth) acrylate, 2-phenyl-1-cyclohexylmethyl (meth) acrylate, 2-phenyl-3-methyl-1-cyclohexylmethyl (meth) acrylate, 2-phenyl-4-methyl-1-cyclohexyl Examples include methyl (meth) acrylate, 2-phenyl-5-methyl-1-cyclohexylmethyl (meth) acrylate, 2-phenyl-6-methyl-1-cyclohexylmethyl (meth) acrylate, and vinyl ether groups and radical polymerization. A monomer having both a functional group can also be used. For example, 2- (vinyloxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxy) propyl (meth) acrylate, (meth) acrylic acid 2 -(Vinyloxyethoxy) isopropyl, vinyl ether of (meth) acrylic acid 2- (vinyloxyisopropoxy) propyl, and the like.

Moreover, the unsaturated monomer which has a fluorine atom can also be used.
For example, the unsaturated monomer having a fluorine atom includes a radical polymerizable monomer having a polyfluoroalkyl group or a polyfluoroether group,
Perfluoroalkyl groups include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluorohexyl, perfluorooctyl, perfluorodecyl, perfluorododecyl, perfluorotetra A decyl group etc. are mentioned.
As a monomer having such a fluorine atom, CH ₂ ═C (CH ₃ ) COOCH ₂ (CF ₂ ) ₄ CF ₃ , CH ₂ ═C (CH ₃ ) COOCH ₂ CH ₂ (CF ₂ ) ₆ CF _{3 , CH 2 = CHCOO (CF 2} ) 6 CF 3, CH 2 = CHCOOCH 2 CH 2 (CF 2) 7 CF 3, CH 2 = CHCOOCH 2 CH 2 (CF 2) 5 CF (CF 3) 2, CH 2 = C (CH
_{3) COOCH (OCOCH 3) CH} 2 (CF 2) 6 CF (CF 3) 2, CH 2 = CHCOOCH 2 CH (OH) CH 2 (CF 2) 6 CF (CF 3) 2, CH 2 = CHCOOCH 2 CH _{2 (CF 2) 8 CF 3} , CH 2 = C (CH 3) COOCH 2 CH 2 NHCO (CF 2) 8 CF 3, CH 2 = CHOCONHCO (CF 2) 7 CF (CF 2 Cl) CF 3, CH 2 _{= CHCOOCH 2 CH 2 N (C} 3 H 7) SO 2 (CF 2) 7 CF 3, CH 2 = CHCOOCH 2 CH 2 CH 2 CH 2 (CF 2) 7 CF 3, CH 2 = C (CH 3) COOCH _{2 CH 2 N (C 2 H} 5) SO 2 (CF 2) 7 CF 3, CH 2 = CHCOOCH 2 CH 2 NHCO (CF 2) 7 CF ₃ , CH ₂ = CHCOO (CH ₂ ) ₃ (CF ₂ ) ₆ CF (CF ₃ ) ₂ , CH ₂ = CHCOOCH ₂ (CF ₂ ) ₁₀ H, CH ₂ = C (CH ₃ ) COOCH ₂ (CF ₂ ) _{10 CF 2 Cl, CH 2 = CHCONHCH} 2 CH 2 OCOCF (CF 3) OC 3 F 7, CH 2 = CHCONHCH 2 CH 2 OCOCF (CF 3) (OC 3 F 6) 2 OC 3 F 7 , and the like.

  Unsaturation containing a cycloalkyl group in order to improve the mechanical strength of the conductive ink coating, especially as an unsaturated monomer copolymerizable with an unsaturated monomer containing a hydroxyl group and / or a carboxyl group as required It is preferable to include an aromatic unsaturated monomer such as a monomer, styrene, or α-methylstyrene.

  As a polymerization method of these acrylic resins, for example, a polymerization initiator can be used by a conventionally known polymerization method such as solution polymerization, dispersion polymerization, suspension polymerization, emulsion polymerization or the like. The solvent used when performing the solution polymerization is not particularly limited. For example, an ester solvent, a ketone solvent, a glycol ether solvent, an aliphatic solvent, an alicyclic solvent, an aromatic solvent, an alcohol solvent. A solvent, water, or the like can be used alone or in combination.

Examples of ester solvents include methyl acetate, ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, (iso) amyl acetate, cyclohexyl acetate, ethyl lactate, 3-methoxybutyl acetate, dimethyl carbonate, ethyl methyl carbonate, di- Examples include n-butyl carbonate.
Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl amyl ketone, isophorone, and cyclohexanone.
Examples of glycol ether solvents include ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n Dipropyl ethers such as propyl ether, propylene glycol mono n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono n-butyl ether, and acetates of these mono ethers, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diprolene glycol dimethyl ether, etc. Le acids and the like.
Examples of the aliphatic solvent include n-heptane, n-hexane, cyclohexane, methylcyclohexane, and ethylcyclohexane.
Examples of the aromatic solvent include toluene and xylene. Examples of the alcohol solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, cyclohexanol, 3-methoxybutanol, diacetone alcohol and the like.
Other solvents include chloroform solvents such as chloroform dichloromethane, trichloromethane, and methylene chloride, ether solvents such as tetrahydrofuran, diethyl ether, 1,4-dioxane, 1,3-dioxolane, N-methylpyrrolidone, Examples also include dimethylformamide, dimethyl sulfoxide, dimethylacetamide and the like.

The polymerization initiator is not particularly limited. For example, 2,2′-azobis (2-methylbutylnitrile), 2,2′-azobis (2-amidinopropane), dihydrochloride 2,2′-azobis (4- Cyano initiators such as cyanopentanoic acid), 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile); persulfates such as potassium persulfate; Hydrogen oxide, peracetic acid, tert-butylperoxy-2-ethylhexanoate, benzoyl peroxide, di-tert-butyl peroxide, 1,1-bis (tert-butylperoxy) -3,3,5- Usual radical initiators such as peroxide-based initiators such as trimethylcyclohexane and tert-butyl hydroperoxide may be mentioned.
At this time, sodium hydrogen sulfite, L-ascorbic acid, Rongalite, sodium metabisulfite or the like can be used as a reducing agent to obtain a redox initiator. These may be used alone or in combination of two or more. The amount to be used may be appropriately set from the desired polymer characteristic values such as the molecular weight of the polymer. For example, when the total amount of monomers is 100 parts by weight, the amount may be 0.01 to 50 parts by weight. Preferably, 0.05 to 20 parts by weight is more preferable.

  Moreover, a polymerization accelerator can also be used as needed. Examples of the polymerization accelerator include various transition metal ions, specifically, ferric sulfate, cupric sulfate, ferric chloride, cupric chloride and the like.

Further, when the unsaturated monomer is polymerized, a chain transfer agent or a regulator can be used for the purpose of adjusting the molecular weight as necessary.
Examples of such chain transfer agents and regulators include alcohols such as methanol, ethanol, propanol, and butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and acetophenone; acetaldehyde, n-butyraldehyde, furfural, benzaldehyde, and the like. Aldehydes; mercaptans such as dodecyl mercaptan, lauryl mercaptan, thioglycolic acid, octyl thioglycolate, thioglycerol, 2-mercaptoethanol, and the like. The amount of these chain transfer agents and regulators used is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 5 parts by weight, for example, when the total polymer component is 100 parts by weight.

  The polymerization conditions in the polymerization method may be appropriately set depending on the polymerization method, and are not particularly limited. For example, the polymerization temperature is preferably room temperature to 200 ° C, more preferably 40 to 140 ° C. What is necessary is just to set reaction time suitably so that a polymerization reaction may be completed according to the composition of a monomer component, the kind of polymerization initiator, etc.

  The conductive ink of the present invention preferably contains 60 to 95% by weight of conductive particles in 100% by weight of the total of conductive particles and binder resin. If the conductive particles are less than 60% by weight, the conductivity is not sufficient, and if it exceeds 95% by weight, the binder resin is reduced, and the adhesion of the conductive ink to the substrate and the mechanical strength of the coating film may be reduced. There is no.

Next, the metal chelate will be described.
In the present invention, the metal chelate is necessary for reacting with a hydroxyl group and a carboxyl group in a binder resin used for the conductive ink and imparting rheological characteristics necessary for the printability of a high-definition pattern in the screen printing method.
Examples of such metal chelates are chelate compounds reacted with metal alkoxides and chelating agents such as β-diketones and ketoesters (ethyl acetoacetate, etc.), and include aluminum chelates, zirconium chelates, titanium chelates and the like. Aluminum chelate is preferably used because of its ease of use.

Among the metal chelates, the aluminum chelate used in the present invention has a molecular weight of 42.
It is preferably 0 or less, and an aluminum acetylacetonate complex is preferred. The acetylacetonate complex has an acetylacetonate group: —O—C (CH ₃ ) ═CH
—CO (CH ₃ ), methyl acetoacetonate group: —O—C (CH ₃ ) ═CH—CO—O—CH ₃ , and ethyl acetoacetonate group: —O—C (CH ₃ ) ═CH— having a CO-O-C ₂ H ₅ and the like. The aluminum chelate used in the present invention preferably has 1 to 3 of these groups in one molecule, and has 1 to 3 acetylacetonate groups or 1 to 3 ethylacetoacetate groups. Chelates are more preferred.
Aluminum chelates with a molecular weight greater than 420, aluminum chelates with 4 or more acetylacetonate groups in one molecule, aluminum chelates with 4 or more ethyl acetoacetate groups, and aluminum chelates with long chain alkyl groups There is a risk that wetting with the conductive particles is hindered and the resistivity is increased.
Typical aluminum chelates include ethyl acetoacetate aluminum diisopropionate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum tris (acetyl acetate), aluminum monoacetyl acetate bis (ethyl acetoacetate). Acetate), aluminum di-n-butoxide monomethyl acetoacetate, aluminum diisobutoxide monomethyl acetoacetate, aluminum disec-butoxide monomethyl acetoacetate and the like.

Of the metal chelates, the zirconium chelate used in the present invention preferably has a molecular weight of 350 or more and 1,000 or less. Further, the zirconium chelate is more preferably a zirconium chelate which is an acetylacetonate complex and contains 1 to 4 acetylacetonate groups and 0 to 2 ethylacetoacetate groups in one molecule. Zirconium chelates having a molecular weight of less than 350 may cause the dispersion state of the conductive ink to become unstable and increase the resistivity.
Typical zirconium chelates include zirconium tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium monobutoxyacetylacetonate bis (ethylacetoacetate), zirconium dibutoxybis (ethylacetoacetate), zirconium tetraacetylacetate. And the like.

Of the metal chelates, titanium chelates used in the present invention preferably have a molecular weight of 250 to 1,500. Further, titanium chelates and alkoxy titaniums that can be represented by (HOR1O) ₂ Ti (OR2) ₂ or (H ₂ NR1O) ₂ Ti (OR2) ₂ . Here, R1 and R2 are hydrocarbon groups. For example, di-i-propoxybis (acetylacetonato) titanium, di-n-ptoxybis (triethanolaminato) titanium, titanium-i-propoxyoctylene glycolate, titanium stearate, titanium acetylacetonate, titanium tetraacetyl Examples include acetonate, polytitanium acetylacetylacetonate, titanium octylene glycolate, titanium ethyl acetoacetate, titanium lactate, and titanium triethanolamate. Zirconium chelates having a molecular weight of less than 250 may cause the dispersion state of the conductive ink to become unstable and increase the resistivity.

The content of the metal chelate used in the present invention is preferably 0.2 to 20 parts by weight, more preferably 2 to 10 parts by weight, based on 100 parts by weight of the binder resin.
If the metal chelate is less than 0.2 parts by weight, the effect of imparting rheological properties necessary for the printability of a high-definition pattern in the screen printing method is small, and if it exceeds 20 parts by weight, the storage elastic modulus G ′ in the rheological properties of the conductive ink is small. Exceeds 50,000, the elastic component becomes too large, screen printing cannot be performed, and the resistance value of the conductive ink may increase.

Furthermore, for the purpose of imparting heat resistance, solvent resistance, chemical resistance, adhesion and the like to the conductive ink of the present invention, a curing agent having a functional group capable of reacting with the functional group of the binder resin is further added. I can do things.
Examples of the curing agent include isocyanate compounds, epoxy resins, aziridine compounds, oxazoline compounds, carbodiimide compounds, amine compounds, acid anhydrides, and the like.
For example, when the functional group of the binder resin is a hydroxyl group, an isocyanate compound or the like can be used as a curing agent. When the functional group of the binder resin is a carboxyl group, an isocyanate compound, an epoxy resin, an aziridine compound, an oxazoline compound, a carbodiimide compound, or the like can be used as a curing agent. Furthermore, when the functional group of the binder resin is an epoxy group, an amine compound, an acid anhydride, or the like can be used as a curing agent.

Examples of the isocyanate compound that can be used as the curing agent include non-blocked isocyanate and blocked isocyanate.
As the isocyanate compound, a polyisocyanate compound is preferable. As the polyisocyanate compound, conventionally known aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate, or blocked isocyanate which is a block body thereof can be used, and these are used alone or in combination of two or more. May be. Examples of the aromatic polyisocyanate include a trimethylolpropane adduct of tolylene diisocyanate, an isocyanurate of tolylene diisocyanate, and an oligomer of 4,4'-diphenylmethane diisocyanate.
Examples of the aliphatic polyisocyanates include biurets of hexamethylene diisocyanate, isocyanurates of hexamethylene diisocyanate, uretdiones of hexamethylene diisocyanate, and isocyanurates of copolymers composed of tolylene diisocyanate and hexamethylene diisocyanate. Examples of the alicyclic polyisocyanate include isocyanurates of isophorone diisocyanate. As the blocked isocyanate, a conventionally known one in which polyisocyanate is blocked with ε-caprolactam, butanone oxime, phenol, active methylene compound or the like can be used.

  Among the curing agents used in the conductive ink of the present invention, an epoxy resin is a compound having an epoxy group, which may be liquid or solid, and is not particularly limited. Those having an average of two or more epoxy groups in the molecule are used. As the epoxy resin, an epoxy resin such as a glycidyl ether type epoxy resin, a glycidyl amine type epoxy resin, a glycidyl ester type epoxy resin, or a cyclic aliphatic (alicyclic type) epoxy resin can be used.

  Examples of the glycidyl ether type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, and cresol novolak type epoxy resin. An epoxy resin having a biphenyl structure between the cresol structure and the cresol structure (Nippon Kayaku Co., Ltd .: NC-3000, etc.), a cresol novolac epoxy resin having a dicyclopentadiene skeleton structure between the cresol structure and the cresol structure Epoxy resin (Nippon Kayaku Co., Ltd .: XD-1000, etc.), α-naphthol novolac epoxy resin, bisphenol A novolac epoxy resin, dicyclopentadiene epoxy resin, Phenyl type epoxy resin, tris (glycidyloxyphenyl) methane, tetrakis (glycidyloxyphenyl) ethane and the like.

  Examples of the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidylmetaaminophenol, and tetraglycidylmetaxylylenediamine.

Examples of the glycidyl ester type epoxy resin include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate.

Examples of the cycloaliphatic (alicyclic) epoxy resin include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate, bis (epoxycyclohexyl) adipate, and the like.
An epoxy resin can be used individually by 1 type or in combination of 2 or more types.

The conductive ink of the present invention includes a curing accelerator, a crosslinking agent, etc. for accelerating the thermosetting of the binder resin and the epoxy resin, thermosetting the epoxy resin, or accelerating the thermosetting. It can be included.
As the curing accelerator, dicyandiamide, tertiary amine compound, phosphine compound, imidazole compound, carboxylic acid hydrazide, dialkylureas such as aliphatic or aromatic dimethylurea and the like, and as the crosslinking agent, an acid anhydride or the like can be used.

Examples of the tertiary amine compound for promoting the thermal curing of the binder resin and the epoxy resin include triethylamine, benzyldimethylamine, 1,8-diazabicyclo (5.4.0) undecene-7, 1,5-diazabicyclo (4.3. 0) Nonene-5 etc. are mentioned. Examples of the phosphine compound include triphenylphosphine and tributylphosphine.
Examples of imidazole compounds for accelerating thermosetting of binder resin and epoxy resin include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2,4-dimethylimidazole, and 2-phenyl. Examples include imidazole compounds such as imidazole, and latent curing accelerators with improved storage stability, such as a type in which these imidazole compounds and epoxy resins are reacted to insolubilize them, or a type in which imidazole compounds are encapsulated in microcapsules. it can.

  Examples of the carboxylic acid hydrazide for accelerating the thermal curing of the binder resin and the epoxy resin include succinic hydrazide and adipic hydrazide. Examples of the acid anhydride include tetrahydrophthalic anhydride, dodecenyl succinic anhydride, methyl nadic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like.

  Two or more of these curing accelerators and crosslinking agents may be used in combination, and the addition amount is preferably in the range of 0.1 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin.

  Among the curing agents used in the conductive ink of the present invention, examples of the aziridine compound include trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N , N-hexamethylene-1,6-bis-1-aziridinecarboxamide, 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane, and the like.

  Among the curing agents used in the conductive ink of the present invention, examples of the oxazoline compound include 2,2 ′-(1,3-phenylene) -bis (2-oxazoline).

  Among the curing agents used in the conductive ink of the present invention, examples of the carbodiimide compound include dicyclohexyl carbodiimide and carbodilite (manufactured by Nisshinbo Co., Ltd., polycarbodiimide resin).

  Among the curing agents used in the conductive ink of the present invention, examples of the amine compound include diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

  Among the curing agents used in the conductive ink of the present invention, examples of the acid anhydride include tetrahydrophthalic anhydride, dodecenyl succinic anhydride, methyl nadic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like.

  The conductive ink of the present invention preferably contains 0.5 to 20 parts by weight of a curing agent with respect to 100 parts by weight of the binder resin. If the curing agent is less than 0.5 parts by weight, sufficient adhesion and heat resistance cannot be imparted to the printed matter, and if it exceeds 20 parts by weight, the unreacted curing agent tends to remain in the conductive ink. It is difficult to provide sufficient adhesion, heat resistance and the like.

The conductive ink of the present invention can be dissolved and diluted with various solvents, and the solid content is preferably 50 to 90% by weight.
The solvent for dilution can be selected according to the solubility of the resin used and the type of printing method.
For example, an ester solvent, a ketone solvent, a glycol ether solvent, an aliphatic solvent, an alicyclic solvent, an aromatic solvent, an alcohol solvent, water or the like may be used in combination. Can do. Moreover, although the solvent etc. which are used at the time of superposition | polymerization of the polyurethane resin mentioned above, a polyurethane urea resin, and an acrylic resin are mentioned, it is not limited to these.

  In the method for producing a conductive ink of the present invention, conductive particles, a binder resin, a metal chelate, a solvent, and the like are blended at a predetermined ratio, mixed with a disper, and mixed and dispersed with a three roll or the like as necessary.

  In addition, the conductive ink of the present invention includes a dispersant, an antifriction agent, an infrared absorber, an ultraviolet absorber, a fragrance, an antioxidant, an organic pigment, an inorganic pigment, an antifoaming agent, and a silane coupling as necessary. An agent, a plasticizer, a flame retardant, a humectant, and the like can be added.

By using the conductive ink of the present invention and printing on a substrate by various printing methods, a high-definition conductive circuit pattern can be formed.
The substrate is not particularly limited, and examples thereof include a polyimide film, a polyparaphenylene terephthalamide film, a polyether nitrile film, a polyether sulfone film, a polyethylene terephthalate film, a polyethylene naphthalate film, and a polyvinyl chloride film. Can be mentioned. In addition, a so-called ITO film, ceramic, glass substrate, or the like in which an ITO (tin-indium oxide) layer is formed on a polymer film such as polyethylene terephthalate or polyethylene naphthalate polycarbonate by sputtering, wet coating, or the like can also be used.

Further, if necessary, for the purpose of further improving the printability of the high-definition pattern wiring, an anchor coat layer can be provided on the base material, and further conductive ink can be printed on the anchor coat layer.
Such an anchor coat layer is not particularly limited as long as it has good adhesion to the substrate and further good adhesion of the conductive ink, and also requires organic fillers such as resin beads and inorganic fillers such as metal oxides. Can be added accordingly. The method of providing these anchor coat layers is not particularly limited, and can be obtained by applying, drying and curing by a conventionally known coating method.

The conductive ink of the present invention can be applied to various conventionally known printing methods, and is particularly preferably applied to screen printing.
In the screen printing method, as described above, it is preferable to use a fine mesh screen, particularly preferably a fine mesh screen of about 400 to 650 mesh, in order to cope with high definition of the conductive circuit pattern. At this time, the open area of the screen is preferably about 20 to 50%. The screen wire diameter is preferably about 10 to 70 μm.
Examples of the screen plate include polyester screens, combination screens, metal screens, and nylon screens. Moreover, when printing the thing of a highly viscous paste state, a high tension | tensile_strength stainless steel screen can be used.
The screen printing squeegee may be round, rectangular or square, and an abrasive squeegee can be used to reduce the attack angle (angle between printing plate and squeegee). Other printing conditions may be conventionally known conditions.

  The conductive circuit pattern printed on the substrate is heated to dry and solidify, and when a curing agent is added to the conductive ink, it is cured. The heating temperature is preferably 80 to 230 ° C., and the heating time is preferably 10 to 120 minutes.

  Hereinafter, the present invention will be specifically described by way of examples. In the examples, “parts” and “%” mean “parts by weight” and “% by weight”, respectively, the hydroxyl value means KOH mg / g, and the acid value means KOH mg / g.

(Synthesis Example 1, Binder 1) Synthesis of Acrylic Resin A reactor equipped with a stirrer, thermometer, reflux condenser, dropping device, nitrogen gas inlet tube, 160 parts of diethylene glycol monoethyl ether acetate, 188 parts of cyclohexyl methacrylate, acrylic 10 parts of 4-hydroxybutyl acid and 2 parts of acrylic acid were charged and heated to 80 ° C. under a nitrogen stream. A mixture of 2 parts of azobisisobutyronitrile and 40 parts of diethylene glycol monoethyl ether acetate was continuously added dropwise over 1 hour, and then reacted at 80 ° C. for 2 hours. Further, 0.4 part of azobisisobutyronitrile was added and aged for 2 hours at 80 ° C., and a copolymer (1) solution having a nonvolatile content of 50%, a number average molecular weight of 51,000, an acid value of 8, and a hydroxyl value of 20 Got. 100 parts of the copolymer (1) solution was dissolved in 25 parts of isophorone to obtain a binder (1) solution having a nonvolatile content of 40%.

(Synthesis example 2, binder 2) Synthesis of acrylic resin In the same reaction apparatus as in synthesis example 1, 240 parts of diethylene glycol monoethyl ether acetate, 104 parts of methyl methacrylate, 80 parts of cyclohexyl methacrylate, 6 parts of 2-ethylhexyl methacrylate, And 10 parts of 4-hydroxybutyl acrylate was prepared, and it heated up to 80 degreeC under nitrogen stream. To this, a mixture of 0.1 part of tert-butyl-peroxy-2-ethylhexanote and 60 parts of diethylene glycol monoethyl ether acetate was continuously added dropwise over 1 hour, followed by reaction at 80 ° C. for 2 hours. Further, 0.1 part of tert-butyl-peroxy-2-ethylhexanote was added twice every 2 hours, and the aging reaction was continued. Thereafter, 166 parts of diethylene glycol monoethyl ether acetate was added to terminate the reaction, and a copolymer (2) solution having a nonvolatile content of 30%, a number average molecular weight of 220,000 and a hydroxyl value of 20 was obtained. This was used as a binder (2) solution.

(Synthesis Example 3, Binder 3) Synthesis of Acrylic Resin In the same reactor as in Synthesis Example 1, 350 parts of diethylene glycol monoethyl ether acetate, 94 parts of methyl methacrylate, 80 parts of cyclohexyl methacrylate, 6 parts of 2-ethylhexyl methacrylate, And 20 parts of 4-hydroxybutyl acrylate was prepared, and it heated up to 80 degreeC under nitrogen stream. To this, a mixture of 0.07 part of tert-butyl-peroxy-2-ethylhexanote and 60 parts of diethylene glycol monoethyl ether acetate was continuously added dropwise over 1 hour, followed by reaction at 80 ° C. for 2 hours. Further, 0.07 part of tert-butyl-peroxy-2-ethylhexanote was added twice every 2 hours, and the aging reaction was continued. Thereafter, 190 parts of diethylene glycol monoethyl ether acetate was added to terminate the reaction, and a copolymer (3) solution having a nonvolatile content of 25%, a number average molecular weight of 350,000 and a hydroxyl value of 39 was obtained. This was used as a binder (3) solution.

(Synthesis Example 4, Binder 4) Synthesis of Acrylic Resin In the same reactor as in Synthesis Example 1, 160 parts of diethylene glycol monoethyl ether acetate, 104 parts of cyclohexyl methacrylate, 90 parts of methyl methacrylate, and 6 parts of 2-ethylhexyl methacrylate. Was heated to 80 ° C. under a nitrogen stream. A mixture of 2 parts of azobisisobutyronitrile and 40 parts of diethylene glycol monoethyl ether acetate was continuously added dropwise over 1 hour, and then reacted at 80 ° C. for 2 hours. Further, 0.4 part of azobisisobutyronitrile was added and aged for 2 hours at 80 ° C., and a copolymer (4) solution having a nonvolatile content of 50%, a number average molecular weight of 47,000, an acid value of 0 and a hydroxyl value of 0 Got. 100 parts of the copolymer (4) solution was dissolved in 25 parts of isophorone to obtain a binder (4) solution having a nonvolatile content of 40%.

(Synthesis Example 5, Binder 5) Synthesis of Polyester Resin 20.3 parts of dimethyl terephthalate, 20.3 parts of dimethyl isophthalate were added to a reactor equipped with a stirrer, thermometer, rectification tube, nitrogen gas introduction tube, and decompression device. Charge 12.9 parts of ethylene glycol, 18.2 parts of neopentyl glycol, and 0.03 part of tetrabutyl titanate, gradually heat to 180 ° C. with stirring under a nitrogen stream, and conduct transesterification at 180 ° C. for 3 hours. I did it. Subsequently, 28.3 parts of sebacic acid was charged and gradually heated to 180 to 240 ° C. to carry out an esterification reaction. Reaction was performed at 240 ° C. for 2 hours, and the acid value was measured. When the acid value became 15 or less, the reaction vessel was gradually depressurized to 1 to 2 torr, and when the predetermined viscosity was reached, the reaction was stopped and taken out. , A hydroxyl value of 5 and an acid value of 1 polymer (5) solution was obtained. 40 parts of the polymer (5) was dissolved in 60 parts of isophorone to obtain a binder (5) solution having a nonvolatile content of 40%.

(Synthesis Example 6, Binder 6) Synthesis of Polyester Resin In the same reaction apparatus as in Synthesis Example 4, dimethyl terephthalate 15.6 parts, dimethyl isophthalate 25.0 parts, ethylene glycol 12.9 parts, neopentyl glycol 18.2 And 0.03 part of tetrabutyl titanate were added, gradually heated to 180 ° C. with stirring under a nitrogen stream, and subjected to a transesterification reaction at 180 ° C. for 3 hours. Subsequently, 28.3 parts of sebacic acid was charged and gradually heated to 180 to 240 ° C. to carry out an esterification reaction. Reaction was carried out at 240 ° C. for 2 hours, and the acid value was measured. When the acid value became 15 or less, the reaction vessel was gradually depressurized to 1 to 2 Torr, and when the predetermined viscosity was reached, the reaction was stopped and taken out. , A hydroxyl value of 10 and an acid value of 1 polymer (6) solution was obtained. 40 parts of the polymer (6) solution was dissolved in 60 parts of isophorone to obtain a binder (6) solution having a nonvolatile content of 40%.

(Synthesis Example 7, Binder 7) Synthesis of polyurethane resin Polyester polyol obtained from isophthalic acid and 3-methyl-1,5-pentanediol in a reactor equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas introduction tube (Kuraray Co., Ltd. “Kuraray polyol P-2030”, Mn = 2033) 127.4 parts, dimethylolbutanoic acid 4.2 parts, isophorone diisocyanate 19.2 parts, and diethylene glycol monoethyl ether acetate 32.5 parts The mixture was reacted at 90 ° C. for 3 hours under a nitrogen stream, and then 115 parts of diethylene glycol monoethyl ether acetate was added to obtain a polymer (7) solution having a number average molecular weight of 18,000, a hydroxyl value of 4 and an acid value of 10. It was. 100 parts of the polymer (7) solution was dissolved in 26 parts of isophorone to obtain a binder (7) solution having a nonvolatile content of 40%.

(Synthesis Example 8, Binder 8) Synthesis of polyurethane urea resin Polyester obtained from isophthalic acid and 3-methyl-1,5-pentanediol in a reactor equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube 90.9 parts of polyol (Kuraray Co., Ltd. “Kuraray polyol P-2011”, Mn = 2011), 3.3 parts of dimethylol butanoic acid, 21 parts of isophorone diisocyanate, and 28 parts of diethylene glycol monoethyl ether acetate were charged. The mixture was reacted at 90 ° C. for 3 hours in an atmosphere, and 72 parts of diethylene glycol monoethyl ether acetate was added thereto to obtain a urethane prepolymer solution having an isocyanate group. Next, a urethane having an isocyanate group was added to a mixture of 3.9 parts of isophoronediamine, 0.44 part of di-n-butylamine, 16.9 parts of diethylene glycol monoethyl ether, and 54.9 parts of diethylene glycol monoethyl ether acetate. 193.7 parts of prepolymer solution was added and reacted at 50 ° C. for 3 hours and then at 70 ° C. for 2 hours to obtain a polymer (8) solution having a number average molecular weight of 33,000, an acid value of 10 and a nonvolatile content of 40%. It was. This was designated as a binder (8) solution.

[Binder 9]
40 parts of JER1256 (number average molecular weight 25,000, epoxy equivalent 7,500, hydroxyl value 190) manufactured by Japan Epoxy Resin Co., Ltd. was dissolved in 60 parts of isophorone to obtain a binder (9) solution having a nonvolatile content of 40%.

[Binder 10]
40 parts of a polyester resin obtained from adipic acid and 3-methyl-1,5-pentanediol (“Kuraray Polyol P-5010” manufactured by Kuraray Co., Ltd., number average molecular weight 5050, hydroxyl value 22, acid value 1) and 60 parts of isophorone To obtain a binder (10) solution having a nonvolatile content of 40%.

[Silver powder A]
Spherical silver powder (tap density 5.5 g / cm ³ , D50 particle size 0.9 μm, specific surface area 0.93 m ² / g) manufactured by DOWA Electronics Co., Ltd. was used as silver powder A.

[Silver powder B]
DOWA Electronics spherical silver powder (tap density 4.0 g / cm ³ , D50 particle size 0
. The silver powder B was 5 μm and the specific surface area was 1.77 m ² / g).

[Silver powder C]
METALOR spherical silver powder (tap density 2.2 g / cm ³ , D50 particle size 0.8 μm,
Silver powder C was defined as 1.40 m ² / g).

[Silver powder D]
Spherical silver powder (tap density 4.5 g / cm ³ , D50 particle size 0.25 μm, specific surface area 1.70 m ² / g) manufactured by Mitsui Kinzoku Co., Ltd. was defined as silver powder D.

[Silver powder E]
Flake silver powder (tap density 4.8 g / cm ³ , D50 particle size 7.9 μm, specific surface area 0.95 m ² / g) manufactured by Fukuda Metal Co., Ltd. was used as silver powder E.

[Silver powder F]
Spherical silver powder (tap density 0.9 g / cm ³ , D50 particle size 5.1 μm, specific surface area 1.91 m ² / g) manufactured by Mitsui Kinzoku Co., Ltd. was used as silver powder F.

[Silver powder G]
METALOR flake silver powder (tap density 6.1 g / cm ³ , D50 particle size 15.3
(μm, specific surface area 0.09 m ² / g) was defined as silver powder G.

[Silver powder H]
Silver powder H was made of SINO-PLATINUM flake silver powder (tap density 2.9 g / cm ³ , D50 particle size 5.2 μm, specific surface area 5.60 m ² / g).

<Measurement of tap density, D50 particle diameter and BET specific surface area of silver powder>
1) D50 particle size The cumulative particle size (D50) of the volume particle size distribution measured using a laser diffraction particle size distribution measuring device “SALAD-3000” manufactured by Shimadzu Corporation was measured.
2) Tap density It measured based on JIS Z 2512: 2006 method.
3) BET specific surface area The value calculated by the following calculation formula from the surface area measured using a flow type specific surface area measuring device “Flowsorb II” manufactured by Shimadzu Corporation was defined as the specific surface area.
Specific surface area (m ² / g) = surface area (m ² ) / powder mass (g)

[Metal chelate A]
As the aluminum chelate, ALCH (general formula (1), solid content 90%) manufactured by Kawaken Fine Chemical Co., Ltd. was used as the metal chelate A.

General formula (1)

[Metal chelate B]
As a titanium chelate, ORGATICS TC-100 (titanium acetylacetonate, solid content 75%) manufactured by Matsumoto Fine Chemical Co., Ltd. was used as metal chelate B.

[Metal chelate C]
As a zirconium chelate, ORGATIXX ZC-540 (zirconium tributoxy monoacetylacetonate, solid content 45%) manufactured by Matsumoto Fine Chemical Co., Ltd. was used as metal chelate C.

[Curing agent]
A block type hexamethylene diisocyanate curing agent, Duranate MF-K60X (Asahi Kasei Chemicals, solid content 60%) was used as the curing agent (1).

<Preparation of conductive ink>
Silver powder, binder resin, metal chelate, and solvent were mixed with a disper at the blending ratios of Examples 1 to 12 and Comparative Examples 1 to 9 shown in Tables 1 and 2, and dispersed with three rolls to prepare a conductive ink. did. The characteristic of the obtained conductive ink was measured by the following method.

<Evaluation of dynamic viscoelastic behavior of conductive ink>
Evaluation of the dynamic viscoelastic behavior of the conductive ink was carried out using a rheometer “AR-G2” manufactured by TA Instruments. The measurement was performed at a temperature of 25 ° C., fixed at a frequency of 1 Hz, and in the range of vibration stress of 1.0 to 10,000 Pa.

[Create test piece]
The conductive inks of Examples 1 to 10 and Comparative Examples 1 to 9 were screen-printed in a 15 mm × 30 mm pattern shape on a 75 μm thick corona-treated polyethylene terephthalate film (hereinafter referred to as PET), and 30 times in a 150 ° C. oven. It was made to dry partially and the electroconductive printed matter with a film thickness of 8-10 micrometers was obtained.

<Measurement of film thickness>
The film thickness of the printed matter was measured using an MH-15M type measuring instrument manufactured by Sendai Nikon Corporation.

<Measurement of manifest resistance>
The surface resistance value of the printed matter was measured using a Loresta APMCP-T400 measuring instrument manufactured by Mitsubishi Chemical Corporation.

<Calculation of volume resistivity>
The volume resistance value was calculated from the surface resistance value and the film thickness measured by the above method. The target value of the volume resistance value is 5.0 × 10 ⁻⁵ Ω · cm or less. In addition, 5.0-8.0 × 10 ⁻⁵ Ω · cm
However, it can be judged that there is no practicality at 8.0 × 10 ⁻⁵ or more.

<Adhesion to ITO laminated film>
Using an ITO laminated film (Nitto Denko Co., Ltd., V270L-TEMP, 75 μm thick) partly etched with hydrochloric acid to remove the ITO layer and expose the substrate (polyethylene terephthalate film), the ITO laminated part Then, the conductive inks of Examples 1 to 12 and Comparative Examples 1 to 9 are screen-printed on the exposed portions of the substrate by etching a pattern of 15 mm × 30 mm so that the film thickness after drying becomes 8 to 10 μm. Then, it was dried in an oven at 150 ° C. for 30 minutes, and the adhesion of this printed matter was evaluated. Evaluation methods and evaluation criteria are as follows.
Tape adhesion test: A tape adhesion test was performed in accordance with JIS K5600.
Cross-cut a total of 100 squares of 10 squares x 10 squares at 1 m width intervals on the printed surface, apply Nichiban cellophane tape (25 mm width) to the printed surface, peel off rapidly, and evaluate the remaining squares went.
○: No peeling (good adhesion level)
Δ: Slightly chipped edges of the mass (adhesion is slightly poor, but practically usable level)
X: Peeling over 1 square is observed (adhesion failure level)

<Adhesion to polyimide film>
Using polyimide film (manufactured by Toray DuPont, Kapton 100H, 25 μm thickness), the conductive inks of Examples 1 to 12 and Comparative Examples 1 to 9 are 15 mm × so that the film thickness after drying is 8 to 10 μm. A 30 mm pattern was screen-printed and dried in a 180 ° C. oven for 30 minutes, and the adhesion of this printed matter was evaluated. Evaluation methods and evaluation criteria are as follows. Nichiban cellophane tape (25 mm width) was affixed to the surface of the printed material and peeled off rapidly to evaluate the adhesion of the printed material.
○: Good adhesion without peeling.
Δ: Slightly peeled off, adhesion slightly poor.
X: There is peeling across the entire surface and poor adhesion.

[Evaluation of fine line printability]
Using a high-precision screen printing apparatus (SERIA manufactured by Tokai Seiki Co., Ltd.), the conductive inks of Examples 1 to 10 and Comparative Examples 1 to 7 and 9 were placed in a 200 mm × 200 mm area with a line width of 40 μm and a line width of On a screen plate having a number of fine wiring patterns of 60 μm (L / S = 40 μm / 60 μm), 20 sheets were continuously printed on corona-treated PET having a thickness of 75 μm, and then dried at 150 ° C. for 30 minutes. The printing conditions are as follows.

(Screen printing conditions)
・ Screen: Stainless steel plate 650 mesh ・ Emulsion thickness: 10 μm
・ Screen frame: 650x550mm
・ Squeegee angle: 70 °
・ Ski Dia Attack Angle: 50 °
・ Squeegee hardness: 80 °
・ Squeegee speed: 20mm / sec ・ Squeegee printing pressure: 10kg
・ Clearance: 3.5mm

(Evaluation of line width variation)
An enlarged photograph (500 times magnification) of the fine wiring portion of the screen printed wiring pattern was taken using a digital microscope (VHX-900 manufactured by Keyence Corporation). The fine line width after printing was read using the small-sized general-purpose image analyzer “LUZEX AP” manufactured by Nireco.
Specifically, for the printed matter on the 5th sheet and the 20th sheet, select 8 arbitrary thin lines respectively, measure the line widths at 460 points per line, a total of 3680 places, the minimum and maximum values The average value, the standard deviation, and the degree of thin line thickness “(average value−40 μm) / 40 μm (%)” were obtained.
Tables 1 and 2 show the average value, the standard deviation, and the thickness of the thin line.
The standard deviation indicates the linearity of the thin line (thickness of the thin line).

The evaluation criteria for the degree of thickening of the thin line “(average value−40 μm) / 40 μm (%)” are as follows.
Less than 25%: almost no thickening of line width is observed, and fine line printability is good 25-40%: slightly thick linewidth is recognized, but fine line printability is practically acceptable level 40% or more: linewidth Is thick, and fine line printability is poor.

Furthermore, the shape of the fine wiring part of the printed wiring pattern was evaluated according to the following criteria. The results are shown in Tables 1 and 2.
○: The fine wiring portion was free from variation in thickness due to meandering, bleeding, and wrinkling, and the boundary line of the fine wiring portion was clear and good.
Δ: Some variation in thickness due to meandering was observed in the fine wiring part, but it did not bleed or wrinkle, and was practically satisfactory.
X: The fine wiring portion was found to have a variation in thickness due to meandering, bleed and wrinkle, and the boundary line was unclear.

As is apparent from Table 1, the conductive inks of Examples 1 to 11 exhibit good volume resistivity, fine line printability, and adhesion to an ITO laminated film.
Moreover, Example 12 which added the hardening | curing agent also has favorable adhesiveness to a polyimide film.

On the other hand, as shown in Table 2, in Comparative Example 1, the D50 particle diameter of the silver powder was less than 0.3 μm, the volume resistivity of the ink coating film was high, and the level was unusable.
On the other hand, in Comparative Example 2, the D50 particle size of the silver powder exceeded 5 μm, and when 20 sheets were printed with fine line printability, the fine lines were severely distorted, so the line width could not be measured. When the mesh portion of the screen printing plate after printing was observed, it was observed that the mesh was clogged with silver powder at many locations, which was a problem due to the large size of D50 particles in the silver powder.

In Comparative Example 3, the tap density of the silver powder was less than 1.0 g / cm ³ , and the volume resistivity of the ink coating film was high, so that it was unusable.

In Comparative Example 4, the specific surface area of the silver powder was less than 0.3 m ² / g, and the volume resistivity of the ink coating film was high, so that it could not be used. Also, the D50 particle size of the silver powder exceeded 5 μm, and when 20 sheets were printed with fine line printability as in Comparative Example 2, the line width could not be measured because the fine lines were severely clogged due to clogging of the mesh. It was.

In Comparative Example 5, the specific surface area exceeds 5.0 m 2 / g, and a large amount of resin is required to cover the surface of the conductive particles, so that the adhesion to the ITO etching film and the polyimide film is inferior. It was.

  In Comparative Example 6, since the binder resin has neither a hydroxyl group nor a carboxyl group, the hydroxyl value is less than 2 (KOHmg / g), and there is no functional group that reacts with the metal chelate, so the storage elastic modulus G ′ is small, and tan δ Was also larger than 1, it was difficult to maintain the shape after the ink transferred to the substrate, and the line was easily “fat”.

In Comparative Example 7, although the binder resin has a functional group that reacts with the metal chelate, since the number average molecular weight is less than 10,000, the storage elastic modulus G ′ is small, and the shape of the binder resin after the ink is transferred to the base material. It was difficult to maintain, and it was easy to “thicken” the line.
On the other hand, in Comparative Example 8, the number average molecular weight of the binder resin exceeded 300,000, the storage elastic modulus of the conductive ink became too high, and screen printing was impossible.

  In Comparative Example 9, no metal chelate was used, the storage elastic modulus G ′ of the conductive ink was small, and tan δ was also larger than 1. Therefore, it was difficult to maintain the shape after the ink transferred to the substrate, and the line “ It was easy to get fat.

Claims (10)

Conductive particles having a tap density of 1.0 to 10.0 (g / cm ³ ), a D50 particle size of 0.3 to 5 μm, and a BET specific surface area of 0.3 to 5.0 m ² / g;
Number average molecular weight (Mn) of 10,000 to 300,000, having at least one of hydroxyl value and acid value, hydroxyl value of 2 to 300 (mgKOH / g), acid value of 20 (mgKOH / g) or less A binder resin,
Containing a metal chelate,
The binder resin is at least one selected from polyester resins, polyurethane resins, polyurethane urea resins, epoxy resins, and acrylic resins,
At 25 ° C., frequency 1 (Hz), and vibration stress 50 (pa), the storage elastic modulus G ′ is 5,000 to 50,000 (Pa), and the loss elastic modulus G ″ is divided by the storage elastic modulus G ′. A conductive ink for a film substrate , wherein the value, tan δ is 1 or less. The conductive ink for film bases of Claim 1 whose tap density of electroconductive particle is 2.0-10.0 (g / cm < ³ >). The conductive ink for film bases according to claim 1 or 2, comprising 0.2 to 20 parts by weight of a metal chelate with respect to 100 parts by weight of the binder resin. The conductive ink for a film substrate according to any one of claims 1 to 3, wherein the metal chelate is an aluminum chelate. The conductive ink for a film substrate according to claim 4, wherein the aluminum chelate has a group selected from the group consisting of an acetylacetonate group, a methylacetoacetonate group and an ethylacetoacetonate group. The conductive ink for a film substrate according to any one of claims 1 to 5, wherein the conductive particles are silver. The conductive ink for film base materials in any one of Claims 1-6 which further contains the hardening | curing agent which has a functional group which can react with the functional group which binder resin has. The conductive ink for a film base according to claim 7 , wherein the curing agent is at least one selected from the group consisting of an isocyanate compound, an epoxy resin, an aziridine compound, an oxazoline compound, an amine compound, and an acid anhydride. The conductive ink for a film base according to claim 7 or 8 , comprising 0.5 to 20 parts by weight of a curing agent with respect to 100 parts by weight of the binder resin. It is an object for screen printing, The electroconductive ink for film base materials in any one of Claims 1-9 characterized by the above-mentioned.