JP2016051692A - Conductive film and manufacturing method of conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for forming a conductive film capable of manufacturing a pattern of the conductive film by a screen printing with good accuracy and forming the conductive film excellent in conductivity and adhesiveness to a substrate, and a manufacturing method of the conductive film.SOLUTION: There is provided a composition for forming a conductive film for screen printing containing at least cupric oxide particle having average particle diameter of 3 to 25 nm, polyalcohol and water, having a viscosity X measured at shear rate of 0.1 sunder a temperature condition of 25°C of 1,000 to 200,000 mPa s, a ratio of the viscosity X to a viscosity Y measured at shear rate of 100 sunder a temperature condition of 25°C of 3.0 to 1,000, the content of water of 0.5 to 150 pts.mass based on 100 pts.mass of polyalcohol and mass ratio of the content of polyalcohol to the content of cupric oxide particle of 0.1 to 2.5.SELECTED DRAWING: None

Description

  The present invention relates to a conductive film and a method for manufacturing a conductive film.

As a method of forming a metal film on a base material, a dispersion of metal oxide particles is applied to the base material by a printing method and then sintered by heat treatment or light irradiation treatment to form a wiring in a metal film or a circuit board. A technique for forming such an electrically conductive portion is known.
Since the above method is simpler, energy-saving, and resource-saving than conventional high-heat / vacuum processes (sputtering) and plating processes, it is highly anticipated in the development of next-generation electronics.

  For example, Patent Document 1 discloses a method of manufacturing a metallized ceramic substrate by firing a conductive metal particle component in a vacuum or an inert atmosphere to form a conductor layer. In Patent Document 1, cupric oxide particles (manufactured by C-I Kasei Co., Ltd., average particle size 48 nm) are specifically used as the conductive metal particles.

JP 2008-109062 A

On the other hand, in order to meet the demand for downsizing and high functionality of electronic devices and electronic devices, further improvement in the accuracy of the pattern shape to be formed is required.
As a method for applying various compositions to a substrate, a screen printing method using a screen printing plate is known.
The inventors of the present invention produced a conductive film by a screen printing method using a dispersion containing cupric oxide particles specifically disclosed in Patent Document 1, and the dispersion produced a screen printing plate. It has been found that the variation in the pattern width of the conductive film is large when the patterned conductive film is difficult to come off. That is, the above dispersion lacked suitability for screen printing.
In addition, recently, there has been a demand for further improvement in the conductivity of the conductive film to be formed and the adhesion to the substrate. However, the dispersion containing cupric oxide particles specifically disclosed in Patent Document 1 is required. The electroconductivity and adhesiveness of the conductive film formed by the screen printing method using the body were not always sufficient, and further improvement was necessary.

In view of the above circumstances, the present invention is capable of accurately producing a conductive film pattern by a screen printing method, and forming a conductive film having excellent conductivity and adhesion to a substrate. It is an object to provide a film-forming composition.
Moreover, this invention also makes it a subject to provide the manufacturing method of the electrically conductive film using this composition for electrically conductive film formation.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by controlling the type and content of the components used and the viscosity of the composition.
That is, it has been found that the above object can be achieved by the following configuration.

(1) cupric oxide particles having an average particle diameter of 3 to 25 nm,
Polyhydric alcohol,
Water at least,
The viscosity X measured at a shear rate of 0.1 s ⁻¹ under a temperature condition of 25 ° C. is 1000 to 200,000 mPa · s,
The ratio of the viscosity X to the viscosity Y measured at a shear rate of 100 s ⁻¹ under a temperature condition of 25 ° C. is 3.0 to 1000,
The water content relative to 100 parts by mass of the polyhydric alcohol is 0.5 to 150 parts by mass,
The composition for electrically conductive film formation for screen printing whose mass ratio of content of polyhydric alcohol with respect to content of a cupric oxide particle is 0.1-2.5.
(2) The composition for electrically conductive film formation as described in (1) in which a polyhydric alcohol contains the polyhydric alcohol whose boiling point is 250 degreeC or more and whose molecular weight is 500 or less.
(3) The conductive film formation according to (1) or (2), further comprising a metal catalyst containing at least one metal element selected from the group consisting of Group 8 to 11 elements of the periodic table Composition.
(4) The composition for electrically conductive film formation as described in (3) whose content of a metal catalyst is 0.005-10.0 mass% with respect to the cupric oxide particle total mass.
(5) The composition for electrically conductive film formation as described in (3) or (4) whose content of a metal catalyst is 0.05-5.0 mass% with respect to the cupric oxide particle total mass.
(6) The composition for electrically conductive film formation in any one of (1)-(5) whose average particle diameter of a cupric oxide particle is 3 nm or more and less than 20 nm.
(7) The composition for electrically conductive film formation in any one of (1)-(6) whose content of water with respect to 100 mass parts of polyhydric alcohols is 20-100 mass parts.
(8) The composition for forming a conductive film according to any one of (1) to (7), further comprising copper particles.
(9) The composition for electrically conductive film formation as described in (8) whose content of a copper particle is 350 mass% or less with respect to the cupric oxide particle total mass.
(10) A step of forming a coating film on a substrate by a screen printing method using the composition for forming a conductive film according to any one of (1) to (9);
Performing at least one treatment selected from the group consisting of heat treatment and light irradiation treatment on the coating film, and reducing the cupric oxide particles to form a conductive film containing metallic copper; A method for producing a conductive film.
(11) The method for producing a conductive film according to (10), wherein a screen printing plate including a screen mesh portion formed of a metal wire is used by screen printing.
(12) The manufacturing method of the electrically conductive film as described in (11) whose diameter of a metal wire is 10-30 micrometers.
(13) The manufacturing method of the electrically conductive film as described in (11) or (12) whose mesh number of a screen mesh part is 300-600 piece / inch.
(14) The manufacturing method of the electrically conductive film in any one of (10)-(13) whose average thickness of a coating film is 5-50 micrometers.
(15) The manufacturing method of the electrically conductive film in any one of (10)-(14) whose base material is a polyethylene terephthalate base material or a polyethylene naphthalate base material.
(16) The method for manufacturing a conductive film according to any one of (10) to (15), wherein the heat treatment atmosphere is a non-oxidative atmosphere, and the heat treatment is performed by a hot plate or an inert oven.

ADVANTAGE OF THE INVENTION According to this invention, the composition for electrically conductive film formation which can manufacture the pattern of an electrically conductive film with a screen printing method accurately, and can form the electrically conductive film which is excellent in electroconductivity and the adhesiveness to a base material. Things can be provided.
Moreover, according to this invention, the manufacturing method of the electrically conductive film using this composition for electrically conductive film formation can also be provided.

Below, the suitable aspect of the manufacturing method of the composition for electrically conductive film formation of this invention and an electrically conductive film is demonstrated in detail.
In addition, in this specification, the numerical range described by "-" shall contain an upper limit and a lower limit. For example, a numerical range of “10-20” includes “10” and “20”.

As a characteristic point of the composition for forming a conductive film of the present invention (hereinafter also simply referred to as “composition”), a predetermined amount of cupric oxide particles having a small average particle diameter, polyhydric alcohol, and the like are used. The viscosity is adjusted.
More specifically, first, in the present invention, since the size of the cupric oxide particles used is small, the surface area of the cupric oxide particles increases, and the surface acts as a reaction point and a reducing agent on the cupric oxide particles. It is presumed that the reaction probability with the polyhydric alcohol increases. This is thought to increase the conductivity of the conductive film and the adhesion between the conductive film and the substrate. In addition, by adjusting the component ratio between such cupric oxide particles and other components, and adjusting the composition so that the viscosity of the composition satisfies a predetermined condition, the composition is preferably used in a screen printing method. I find out what I can do.

The composition of the present invention contains at least cupric oxide particles having an average particle diameter of 3 to 25 nm, a polyhydric alcohol, and water.
Below, the various components contained in a composition are explained in full detail first, and the manufacturing method of the electrically conductive film using this composition is explained in full detail after that.

<Cupric oxide particles>
The composition for forming a conductive film contains cupric oxide particles. The cupric oxide particles are reduced by a heat treatment and / or a light irradiation treatment described later, and constitute metallic copper in the conductive film.
The “cupric oxide” in the present invention is a compound that does not substantially contain copper that has not been oxidized. Specifically, in crystal analysis by X-ray diffraction, a peak derived from cupric oxide is detected. And a compound in which no metal-derived peak is detected. Although it is not limited that copper which is not oxidized is not included substantially, it is preferred that content of copper (metal copper) which is not oxidized is 1 mass% or less to cupric oxide particles. .

The average particle diameter of the cupric oxide particles is 3 to 25 nm, the suitability of the composition for the screen printing method is more excellent, the conductivity of the formed conductive film is more excellent, and the formed conductive film It is preferably 3 nm or more and less than 20 nm, preferably 3 to 15 nm in that at least any one of the adhesion to the base material is satisfied (hereinafter also simply referred to as “the effect of the present invention is more excellent”). Is more preferable, and 3 to 10 nm is more preferable.
In addition, the said average particle diameter is an average value (what is called average primary particle diameter) of the primary particle diameter of a cupric oxide particle, and a transmission electron microscope (TEM) observation or a scanning electron microscope (SEM) observation is carried out. Then, the equivalent circle diameters of at least 400 cupric oxide particles are measured, and they are obtained by arithmetic averaging. The equivalent circle diameter means the diameter of a circle corresponding to the same area as the area of the two-dimensional image of the observed cupric oxide particles.

  The content (ratio) of cupric oxide particles having a particle size (primary particle size) of 25 nm or more is not particularly limited, but is 5 mass with respect to the total mass of cupric oxide particles in that the effect of the present invention is more excellent. % Or less is preferable, and 3% by mass or less is more preferable. Although a minimum in particular is not restrict | limited, 0 mass% is mentioned.

In addition, even if a cupric oxide particle uses a commercial item, it may be manufactured with a well-known manufacturing method.
As a method for producing cupric oxide particles, for example, there are a method of granulating in a gas phase (gas phase method) and a method of granulating in a wet method (wet method). The copper particles are preferably produced by a wet method. It is because it becomes possible to control to a desired particle shape by granulating by a wet method.
For the synthesis of cupric oxide particles, for example, as described in JP-A-2003-183024, a copper compound such as copper nitrate (for example, cupric hydroxide, cupric chloride, bromide) By reacting a divalent salt such as cupric, cupric iodide, cupric sulfate, and cupric nitrate) with a base (for example, an alkali metal compound or an organic amine compound), A method of producing and granulating cupric oxide particles by heating is preferred. That is, cupric oxide particles can be produced by reacting a copper compound with a base and then performing a heat treatment.
According to this method, it is possible to synthesize cupric oxide particles at a lower temperature and in a shorter time, and the desired particle shape / distribution can be controlled.
When granulating by a wet method, it is preferable to use water or a polyhydric alcohol having a boiling point of 150 to 300 ° C. as a solvent. The reason for this is that the solvent is less likely to volatilize during heat dehydration and that the prepared cupric oxide particles are excellent in dispersion stability. The type of polyhydric alcohol is the same as that described later.
In addition, in the said method (wet method), after manufacturing a cupric oxide particle (granulation), it is preferable to perform the process wash | cleaned with water with respect to a cupric oxide particle. By carrying out the washing treatment, impurities (for example, a salt such as sodium nitrate) can be removed, the dispersion stability of the cupric oxide particles is improved, and the viscosity of the composition can be easily controlled. The washing method is not particularly limited, but after adding cupric oxide particles in water and redispersing, stirring for a predetermined time, an operation of recovering cupric oxide particles from water by centrifugation or membrane treatment. Can be mentioned. This operation may be performed a plurality of times.

<Polyhydric alcohol>
The composition for forming a conductive film contains a polyhydric alcohol. The polyhydric alcohol functions as a reducing agent for the cupric oxide particles.
The polyhydric alcohol is not particularly limited as long as it is a compound having two or more alcoholic hydroxy groups.
The boiling point of the polyhydric alcohol is not particularly limited, but is preferably 250 ° C. or higher, more preferably 250 to 330 ° C., and further preferably 270 to 310 ° C. in terms of more excellent effects of the present invention. The boiling point is a value measured at 1 atm.
The melting point of the polyhydric alcohol is not particularly limited, but is preferably −50 ° C. or higher, more preferably 0 ° C. or higher, and further preferably 20 ° C. or higher in terms of more excellent effects of the present invention. In addition, melting | fusing point is a measured value under 1 atmosphere.
The molecular weight of the polyhydric alcohol is not particularly limited, but is preferably 500 or less, more preferably 50 to 250, and still more preferably 70 to 150, from the viewpoint that the effects of the present invention are more excellent.
A polyhydric alcohol can be used individually by 1 type or in combination of 2 or more types. For example, as the polyhydric alcohol, only a polyhydric alcohol having a boiling point of 250 ° C. or higher (preferably having a molecular weight of 500 or less) may be used, or a polyhydric alcohol A having a boiling point of 250 ° C. or higher (preferably having a molecular weight of 500 or less). ) And polyhydric alcohol B having a boiling point of less than 250 ° C. (preferably having a molecular weight of 500 or less) may be used in combination.

  Specific examples of the polyhydric alcohol include, for example, ethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, , 5-pentanediol, 1,2-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,2-octanediol, 1, 8-octanediol, 1,3-nonanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, 2,7-dimethyl-3,6-octanediol, 2,2- Dibutyl-1,3-propanediol, 1,2-dodecanediol, 1,12-dodecanediol, 1,2-tetradecanediol, 1,1 -Tetradecanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-pentanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1-hydroxymethyl-2- ( 2-hydroxyethyl) cyclohexane, 1-hydroxy-2- (3-hydroxypropyl) cyclohexane, 1-hydroxy-2- (2-hydroxyethyl) cyclohexane, 1-hydroxymethyl-2- (2-hydroxyethyl) benzene, 1-hydroxymethyl-2- (3-hydroxypropyl) benzene, 1-hydroxy-2- (2-hydroxyethyl) benzene, 1,2-benzyldimethylol, 1,3-benzyldimethylol, 1,2-cyclohexane Diol, 1,3-cyclohexanediol, 1, -Divalent alcohols such as cyclohexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol; glycerin (propane-1,2,3-triol), butane-1,2,4-triol, hexane-1,2,6-triol , Trivalent alcohols such as 3-methylpentane-1,3,5-triol and trimethylolpropane (2- (hydroxymethyl) -2-ethylpropane-1,3-diol); cyclooctane-1,3 And tetravalent alcohols such as 5,7-tetraol and pentaerythritol (2,2-bis (hydroxymethyl) -1,3-propanediol).

<Water>
The composition for forming a conductive film contains water.
The type of water is not particularly limited, but water having a level of purity higher than that of ion-exchanged water, for example, reverse osmosis filtered water (RO water), milli-Q water, distilled water, and the like is preferable.

<Other optional components>
The composition of the present invention may contain components other than the above components.
For example, the composition may further contain a metal catalyst.
The metal catalyst preferably contains at least one metal element (metal) selected from the group consisting of groups 8 to 11 of the periodic table. The metal element is at least one metal element selected from the group consisting of gold, silver, copper, platinum, palladium, rhodium, iridium, ruthenium, osmium, and nickel in that the conductivity of the conductive film is more excellent. Preferably, it is at least one metal element selected from the group consisting of silver, platinum, palladium, and nickel, more preferably palladium or platinum, and most preferably palladium. That is, the metal catalyst is preferably a metal catalyst containing palladium because the conductivity of the obtained conductive film is more excellent.
The form of the metal catalyst is not particularly limited, and may be any metal salt, complex, particle or the like.

As a suitable aspect of a metal catalyst, palladium salt and a palladium complex are mentioned, for example. Of these, a palladium salt is preferable.
The kind of palladium salt is not particularly limited, and specific examples thereof include palladium hydrochloride, nitrate, sulfate, carboxylate, sulfonate, phosphate, phosphonate and the like. Of these, carboxylate is preferable.
The number of carbon atoms of the carboxylic acid forming the carboxylate is not particularly limited, but is preferably 1 to 10, more preferably 1 to 5. The carboxylic acid forming the carboxylate may have a halogen atom (preferably a fluorine atom).

  The metal catalyst is preferably at least one compound selected from the group consisting of palladium acetate, palladium trifluoroacetate and tetrakis (triphenylphosphine) palladium, and more preferably palladium acetate.

In the composition, an organic solvent may be contained in addition to water. The organic solvent does not include the polyhydric alcohol.
Organic solvents include ether solvents such as diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dioxane, triglyme, tetraglyme, methyl acetate, butyl acetate, benzyl benzoate, dimethyl carbonate, ethylene Ester solvents such as carbonate, γ-butyrolactone, caprolactone, hydrocarbon solvents such as benzene, toluene, ethylbenzene, tetralin, hexane, octane, cyclohexane, halogenated hydrocarbon solvents such as dichloromethane, trichloroethane, chlorobenzene, N, N -Dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone (N-methyl-2-pyrrolidone), Kisamechirurin triamide, N, N-dimethylimidazolidinone amide or cyclic amide solvent such as, sulfone solvents dimethyl sulfone, sulfoxide solvents such as dimethyl sulfoxide can be exemplified.
Especially, the water-soluble organic solvent is preferable at the point which the effect of this invention is more excellent. The water-soluble organic solvent is an organic solvent that is compatible with water. More specifically, the water-soluble organic solvent is a solvent that is mixed with water at an arbitrary ratio to form a uniform system.
Moreover, as a water-soluble organic solvent, the thing of boiling point 100 degreeC or more and less than 250 degreeC is preferable, and the thing of boiling point 150 degreeC or more and less than 250 degreeC is more preferable at the point which the effect of this invention is more excellent.
Examples of the water-soluble organic solvent include organic solvents having a heterocyclic structure in the molecule such as N-methylpyrrolidone, 1,4-dioxane, furfuryl alcohol, tetrahydrofurfuryl alcohol, butanol, 2-butanol, and pentanol. And monohydric alcohol solvents such as

Moreover, as other arbitrary components other than the said metal catalyst, additives, such as water-soluble polymer, surfactant, and thixotropic agent, are mentioned, for example.
Note that the composition may contain copper particles.
Although the aspect of a copper particle is not specifically limited, For example, it is preferable that it is particulate copper whose average particle diameter is 1 nm-10 micrometers.
The particulate form refers to a small granular form, and specific examples thereof include a spherical shape and an ellipsoidal shape. It is not necessary to be a perfect sphere or ellipsoid, and a part may be distorted.
The average particle diameter of the copper particles is preferably in the range of 1 nm to 10 μm, more preferably 100 nm to 8 μm, and even more preferably 500 nm to 5 μm.
In addition, an average particle diameter points out an average primary particle diameter. The average particle diameter is determined by measuring the particle diameter (diameter) of at least 50 copper particles by observation with a transmission electron microscope (TEM) and arithmetically averaging them. In addition, when the shape of a copper particle is not a perfect circle shape in an observation figure, a major axis is measured as a diameter.

<Composition for forming conductive film>
The composition for forming a conductive film contains at least the cupric oxide particles, polyhydric alcohol, and water described above.
The content of the cupric oxide particles in the composition is not particularly limited, but is preferably 10 to 60% by mass and preferably 20 to 45% by mass with respect to the total mass of the composition in terms of more excellent effects of the present invention. More preferably, 20-30 mass% is further more preferable.
Although the content of the polyhydric alcohol in the composition is not particularly limited, it is preferably 10 to 70% by mass and more preferably 20 to 50% by mass with respect to the total mass of the composition in that the effect of the present invention is more excellent. 30 to 45% by mass is more preferable.
The content of water in the composition is not particularly limited, but is preferably from 0.1 to 35% by mass, more preferably from 5 to 35% by mass with respect to the total mass of the composition in terms of more excellent effects of the present invention. 10 to 25% by mass is more preferable, and 12 to 25% by mass is particularly preferable.

The content of the polyhydric alcohol in the composition is preferably 50 to 300% by mass, more preferably 70 to 250% by mass, based on the total mass of the cupric oxide particles, in that the effect of the present invention is more excellent. 100-230 mass% is further more preferable.
The content of water in the composition is preferably 0.1 to 300% by mass, more preferably 10 to 300% by mass, based on the total mass of the cupric oxide particles, in that the effect of the present invention is more excellent. 30-200 mass% is further more preferable, and 30-150 mass% is especially preferable.

When the metal catalyst is contained in the composition, the content of the metal catalyst in the composition is not particularly limited, but is 0.005 to 7.7 based on the total mass of the composition in that the effect of the present invention is more excellent. 0 mass% is preferable, 0.01-3.0 mass% is more preferable, 0.03-2.0 mass% is further more preferable, 0.05-2.0 mass% is especially preferable.
When the organic solvent is contained in the composition, the content of the organic solvent in the composition is not particularly limited, but 0.1 to 30 mass relative to the total mass of the composition in that the effect of the present invention is more excellent. % Is preferable, 5 to 30% by mass is more preferable, and 10 to 25% by mass is further preferable.

When the metal catalyst is contained in the composition, the content of the metal catalyst in the composition is 0.005 to 10% by mass relative to the total mass of the cupric oxide particles in that the effect of the present invention is more excellent. Is preferable, 0.01-5 mass% is more preferable, 0.03-5 mass% is further more preferable, 0.05-5 mass% is especially preferable.
When the said organic solvent is contained in a composition, content of the organic solvent in a composition is 0.1-300 mass% with respect to the cupric oxide particle total mass by the point which the effect of this invention is more excellent. Is preferable, 10 to 300% by mass is more preferable, 30 to 200% by mass is further preferable, and 30 to 150% by mass is particularly preferable.
When copper particles are contained in the composition, the content of the copper particles in the composition is preferably 1 to 350% by mass with respect to the total mass of the cupric oxide particles, in that the effect of the present invention is more excellent. 10-200 mass% is more preferable, and 20-100 mass% is further more preferable.

In the composition, the content of water with respect to 100 parts by mass of the polyhydric alcohol is 0.5 to 150 parts by mass, and 10 to 120 parts by mass is preferable in that the effect of the present invention is more excellent. Part is more preferred.
When the water content is less than 0.5 parts by mass, the composition is difficult to pass through the screen printing plate, or the screen printing aptitude is inferior, such as the pattern accuracy of the formed conductive film is inferior (hereinafter simply referred to as “screen printing aptitude”. Also inferior ”). When the water content exceeds 150 parts by mass, the conductivity of the formed conductive film and the adhesion to the substrate are inferior, and the screen printing suitability is also inferior.

In the composition, the mass ratio of the polyhydric alcohol content to the cupric oxide particle content (polyhydric alcohol content / cupric oxide particle content) is 0.1 to 2.5. In view of more excellent effects of the present invention, 0.5 to 2.5 is preferable, and 1.0 to 2.0 is more preferable.
When the mass ratio is less than 0.1, the conductivity is inferior. When the said mass ratio is over 2.5, it is inferior to screen printing aptitude.

The viscosity X of the composition measured at a shear rate of 0.1 s ⁻¹ (0.1 (1 / s)) under a temperature condition of 25 ° C. is 1000 to 200,000 mPa · s, and the effect of the present invention is effective. In the point which is more excellent, 5000-140,000 mPa * s is preferable and 10,000-100,000 mPa * s is more preferable.
When the viscosity X of the composition is less than 1000 mPa · s, and when it exceeds 200,000 mPa · s, the screen printability is poor.

The ratio of the viscosity X to the viscosity Y of the composition measured at a shear rate of 100 s ⁻¹ under a temperature condition of 25 ° C. (viscosity X / viscosity Y) is 3.0 to 1000, and the effect of the present invention is more effective. In the point which is excellent, 3.5-200 are preferable, 7.0-140 are more preferable, and 10.0-100 are more preferable.
When the above ratio is less than 3.0 and when it exceeds 1000, the screen printing suitability is poor.
The viscosity X represents the viscosity of the composition when the shear rate is low, and the viscosity Y represents the viscosity of the composition when the shear rate is high. If the viscosity X and the viscosity Y are within the predetermined range, when the composition is pushed into the screen printing plate by bringing the squeegee into contact with the composition, the viscosity of the composition is lowered by the pushing force by the squeegee, and screen printing is performed. The composition easily applied through the plate and the composition applied on the substrate has a high viscosity, so that the spread of the pattern is suppressed.

As a method for measuring the viscosity X and the viscosity Y, the composition is adjusted to 25 ° C. using HAAKE MARSIII (device name) manufactured by Eihiro Seiki Co., Ltd., and measurement is performed. The test is performed using a parallel disk system, in which the diameter of the disk is 25 mm and the clearance is 0.10 mm to 0.15 mm. An ethylene glycol aqueous solution controlled at 25 ° C. by a high and low temperature circulator of Rabo Japan Co. is circulated to the measuring section to keep the temperature uniform. Then, the disk is rotated at a constant speed so that the shear rate is 0.1 s ⁻¹ or 100 s ^−1, and the rotational torque at that time is measured to obtain the viscosity measurement.

  The method for preparing the composition is not particularly limited, and a known method can be adopted. For example, after adding cupric oxide particles, polyhydric alcohol, water, and other components as required, ultrasonic method (for example, treatment with an ultrasonic homogenizer), mixer method, three-roll method, A composition can be obtained by dispersing the components by a known means such as a ball mill method.

<Method for producing conductive film>
Next, the manufacturing method of the electrically conductive film using the said composition is explained in full detail.
The method for producing a conductive film includes a step of applying the above composition onto a substrate by a screen printing method to form a coating film (coating film forming step), a heat treatment and / or light irradiation on the coating film. At least a step of forming a conductive film (conductive film forming step) by performing a treatment (so-called reduction treatment).
Hereinafter, each process is explained in full detail.

[Coating film forming process]
This step is a step of forming a coating film on the substrate by the screen printing method using the conductive film forming composition. The precursor film before the reduction treatment is obtained in this step.
Below, the base material used at this process is explained in full detail first, and the procedure of this process is explained in full detail after that.
In addition, it is as above-mentioned about the composition for electrically conductive film formation used.

(Base material)
The substrate used in this step is not particularly limited, and examples of the material used for the substrate include resin, paper, glass, silicon-based semiconductor, compound semiconductor, metal oxide, metal nitride, wood, or These composites can be mentioned.
More specifically, as the base material, low density polyethylene resin, high density polyethylene resin, ABS (acrylonitrile-butadiene-styrene) resin, acrylic resin, styrene resin, vinyl chloride resin, polyester resin (polyethylene terephthalate), polyacetal resin , Resin base materials such as polysulfone resin, polyetherimide resin, polyetherketone resin, cellulose derivative; uncoated printing paper, fine coated printing paper, coated printing paper (art paper, coated paper), special printing paper, Paper substrates such as copy paper, unbleached wrapping paper (both kraft paper for heavy bags, both kraft paper), bleached wrapping paper (bleached kraft paper, pure white roll paper), coated balls, chipboard, cardboard, etc .; soda glass , Glass substrates such as borosilicate glass, silica glass, and quartz glass; amorphous silicon Silicon semiconductor substrate such as polysilicon, compound semiconductor substrate such as CdS, CdTe, GaAs, etc .; metal substrate such as copper plate, iron plate, aluminum plate; alumina, sapphire, zirconia, titania, yttrium oxide, indium oxide, ITO (Indium tin oxide), IZO (indium zinc oxide), Nesa (tin oxide), ATO (antimony-doped tin oxide), fluorine-doped tin oxide, zinc oxide, AZO (aluminum-doped zinc oxide), gallium-doped zinc oxide, Other inorganic base materials such as aluminum nitride and silicon carbide; paper-phenolic resin, paper-epoxy resin, paper-polyester resin and other paper-resin composites, glass cloth-epoxy resin, glass cloth-polyimide resin, glass cloth- Examples thereof include a composite substrate such as a glass-resin composite such as a fluororesin.

  Especially, as a base material, for example, a polyimide base material, a polyethylene terephthalate base material, a polyethylene naphthalate base material, a polycarbonate base material, a cellulose ester base material, a polyvinyl chloride base material, a polyvinyl acetate base material, a polyurethane base material, At least one selected from the group consisting of a silicone substrate, a polyvinyl ethyl ether substrate, a polysulfide substrate, a polyolefin substrate, a polyacrylate substrate, and a glass epoxy substrate is preferable. Furthermore, Preferably, a polyethylene terephthalate base material or a polyethylene naphthalate base material is mentioned.

(Process procedure)
In this step, the coating is formed by applying the composition onto the substrate by screen printing.
As the procedure of the screen printing method, a known method can be carried out, and a known screen printer can be used.
The screen printing method refers to a method in which a screen printing plate including a screen mesh portion having a predetermined pattern is placed on a substrate, the composition is applied onto the screen printing plate, and then the composition is removed from the screen mesh portion by a squeegee. It is a method of extruding and passing a screen printing plate to give a composition on a substrate.

The type of screen printing plate used in this step is not particularly limited, and a screen printing plate having a screen mesh portion formed from a metal wire or a screen having a screen mesh portion formed from a resin fiber (for example, polyester). A screen having a screen mesh portion (hereinafter, also simply referred to as “metal mesh portion”) formed from a metal wire in terms of excellent durability and better pattern accuracy of the formed conductive film, such as a printing plate. A printing plate is preferred.
The screen mesh portion is formed by weaving metal wires made of metal such as stainless steel vertically and horizontally, for example.
The screen printing plate has a frame part and a screen mesh part arranged in the frame part.

The diameter of the metal wire constituting the metal mesh portion is not particularly limited, but is 5 to 300 μm in that at least one of the pattern accuracy of the conductive film to be formed, the conductivity of the conductive film, and the adhesion of the conductive film is more excellent. Is preferable, 10 to 100 μm is more preferable, 10 to 30 μm is further preferable, 10 to 25 μm is particularly preferable, and 10 to 20 μm is most preferable.
In addition, when the cross section of a metal wire is not perfect circle shape, a major axis is considered as the said diameter.

  The number of meshes in the metal mesh portion is not particularly limited, but is 100 to 800 / inch in that at least one of pattern accuracy of the conductive film to be formed, conductivity of the conductive film, and adhesion of the conductive film is more excellent. Preferably, 300 to 600 lines / inch is more preferable, and 400 to 600 lines / inch is more preferable.

  The shape in particular which gives a composition on a base material is not restrict | limited, The surface shape which covers the whole base material may be sufficient, and pattern shape (for example, wiring shape, dot shape) may be sufficient. The shape can be adjusted by changing the shape of the screen mesh portion in the screen printing plate.

In this step, if necessary, after applying the conductive film-forming composition to the substrate, a drying treatment may be performed to remove the solvent. By removing the remaining solvent, it is possible to suppress the generation of minute cracks and voids due to the vaporization and expansion of the solvent in the conductive film forming step described later. It is preferable in terms of adhesion.
As a method for the drying treatment, a hot air dryer or the like can be used, and the temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. or more and less than 150 ° C. More preferably, the heat treatment is performed at 70 ° C. to 120 ° C.
The drying time is not particularly limited, but is preferably 1 to 60 minutes because the adhesion between the substrate and the conductive film becomes better.

Although the average thickness of the coating film formed at this process is not restrict | limited in particular, 1-500 micrometers is preferable, 3-70 micrometers is more preferable, and 5-50 micrometers is more preferable at the point which the effect of this invention is more excellent.
In addition, the average thickness of a coating film measures the thickness of arbitrary 5 points | pieces of a coating film, and averages them.

[Conductive film forming step]
In this step, a heat treatment and / or a light irradiation treatment is performed on the coating film formed on the base material (or a dry coating film when the drying process is performed) to form a conductive film containing metallic copper. It is a process.
By performing the heat treatment and / or the light irradiation treatment, the cupric oxide particles are reduced and further fused to obtain metallic copper. More specifically, cupric oxide particles are reduced to form metallic copper particles, the produced metallic copper particles are fused together to form grains, and the grains are bonded and fused together to form metallic copper. A conductive film containing is formed.
When copper particles are contained in the composition, metal copper particles obtained by reduction of cupric oxide particles and copper particles in the composition are fused to form grains. By containing copper particles, the conductive film can be thickened, and the surface resistance and line resistance can be further reduced.

The heat treatment conditions are such that a conductive film that is more excellent in conductivity can be formed in a short time, and the heating temperature is not particularly limited, but is preferably 80 to 200 ° C, more preferably 120 to 180 ° C. The heating time is preferably 5 to 120 minutes, more preferably 30 to 90 minutes.
The heating means is not particularly limited, and a known heating means such as a hot plate or an inert oven can be used.
In the present invention, the conductive film can be formed by heat treatment at a relatively low temperature, and therefore, the process cost is low.

Unlike the heat treatment described above, the light irradiation treatment can reduce and sinter to metallic copper by irradiating light on the portion to which the coating film is applied at room temperature for a short time, and heating for a long time. The base material does not deteriorate due to the above, and the adhesion between the conductive film and the base material becomes better.
The light source used in the light irradiation treatment is not particularly limited, and examples thereof include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of radiation include electron beams, X-rays, ion beams, and far infrared rays. Further, g-line, i-line, deep-UV light (deep ultraviolet light), and high-density energy beam (laser beam) are also used.
Specific examples of preferred embodiments include scanning exposure with an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, and infrared lamp exposure.
The light irradiation is preferably light irradiation with a flash lamp, and more preferably pulsed light irradiation with a flash lamp. Irradiation with high-energy pulsed light can concentrate and heat the surface of the portion to which the coating film has been applied in a very short time, so that the influence of heat on the substrate can be extremely reduced.
The irradiation energy of the pulse light is preferably 1~100J / cm ^2, more preferably 1~30J / cm ^2, preferably 1μ seconds ~100m sec as a pulse width, and more preferably 10μ sec ~10m seconds. The irradiation time of the pulsed light is preferably 1 to 100 milliseconds, more preferably 1 to 50 milliseconds, and further preferably 1 to 20 milliseconds.
In addition, when a light irradiation process is implemented, it is estimated that the cupric oxide particle | grains act as a photothermal conversion substance which absorbs light and converts it into heat, and it has played the role which transmits heat in a coating film.

  The heat treatment and the light irradiation treatment may be performed alone or both may be performed simultaneously. Moreover, after performing one process, you may perform the other process further.

  In the present invention, the heat treatment and the light irradiation treatment may be performed in either a non-oxidizing atmosphere (non-oxygen atmosphere) or an oxidizing atmosphere. The non-oxidizing atmosphere is intended to be an atmosphere having an oxygen concentration of 50 ppm by volume or less, and examples thereof include an inert gas atmosphere such as nitrogen and argon, and a reducing gas atmosphere such as hydrogen. Examples of the oxidizing atmosphere include an air atmosphere and an oxygen atmosphere. Especially, it is preferable to implement in non-oxidizing atmosphere at the point which the effect of this invention is more excellent.

[Conductive film]
By conducting the above-described method for producing a conductive film using the conductive film forming composition of the present invention, a conductive film containing a metal conductor substantially made of metallic copper is produced.
The average thickness of the conductive film is not particularly limited, and an optimum film thickness is appropriately selected according to the application used. For example, 10-1000 nm is preferable from the point of an organic thin-film transistor electrode use, 10-500 nm is more preferable, 20-200 nm is further more preferable, 50-150 nm is especially preferable. Further, for example, from the viewpoint of printed wiring board use, 0.01 to 500 μm is preferable, 0.1 to 100 μm is more preferable, and 0.5 to 50 μm is further preferable.
The average thickness of the conductive film is measured using a surface shape measuring device DEKTAK-3 (manufactured by ULVAC) under the conditions of a scanning distance of 10 mm and a scanning speed of 0.2 mm / sec.

The conductive film may be provided on the entire surface of the base material or in a pattern. The patterned conductive film is useful as a conductor wiring (wiring) such as a printed wiring board.
As a method of obtaining a patterned conductive film, the above-mentioned composition for forming a conductive film was applied to a substrate in a pattern, and the above heat treatment and / or light irradiation treatment was performed, or the entire surface of the substrate was provided. For example, a method of etching the conductive film in a pattern may be used.
The etching method is not particularly limited, and a known subtractive method, semi-additive method, or the like can be employed.

  When a patterned conductive film is configured as a multilayer wiring board, an insulating layer (insulating resin layer, interlayer insulating film, solder resist) is further laminated on the surface of the patterned conductive film, and further wiring (metal) is formed on the surface. Pattern) may be formed.

  The base material (base material with a conductive film) having the conductive film obtained above can be used for various applications. For example, a printed wiring board, a thin film transistor (TFT), a flexible printed wiring board (FPC), RFID (radio frequency identifier), etc. are mentioned.

  The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

(Synthesis of cupric oxide particles)
A predetermined amount of copper nitrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in purified water to prepare a 0.1 mol / l aqueous copper nitrate solution in advance. 100 ml of ethylene glycol was placed in a glass 200 ml flask and heated to 90 ° C. in an oil bath. 20 ml each of the copper nitrate aqueous solution and 0.2 mol / l sodium hydroxide aqueous solution were added thereto within 10 seconds and heated for 10 minutes to obtain cupric oxide particles. After that, after collecting the particles by centrifugation (20000 G, 30 minutes), the work of redispersing in water is repeated three times to remove impurities such as sodium nitrate that replicates, and the solvent water is removed by vacuum drying. Thus, a powder of cupric oxide particles was obtained. By XRD (X-ray diffraction method) analysis, strong diffraction peaks derived from the (002) and (111) planes are observed around 35.5 ° and 38 °, respectively, and the obtained particles are cupric oxide. It was confirmed. Moreover, as a result of observation with a transmission electron microscope (TEM), the average particle diameter of the obtained cupric oxide particles was 5 nm, and the ratio of particles having a particle diameter of 25 nm or more was 2%.

Moreover, the copper oxide particle from which an average particle diameter differs was manufactured by adjusting the density | concentration (ratio constant) of copper nitrate and sodium hydroxide, and the ratio of ethylene glycol / water which is a solvent. Specifically, copper oxide particles having an average particle diameter of 3 nm, 10 nm, 15 nm, 20 nm, 25 nm, and 34 nm were prepared. The average particle diameter was determined by measuring the equivalent circle diameters of 400 cupric oxide particles by transmission electron microscope (TEM) observation and arithmetically averaging them.
In Comparative Example 5, which will be described later, cupric oxide particles (manufactured by C-I Kasei Co., Ltd., average particle size 48 nm) were used.

<Example 1>
(Preparation of conductive film forming composition 1)
The obtained cupric oxide particles, trimethylolpropane, water, N-methylpyrrolidone (NMP), and palladium acetate as a catalyst were mixed so as to have an addition amount shown in Table 1, and a revolution mixer The composition 1 for electrically conductive film formation was obtained by processing for 5 minutes with (THINKY company make, Awatori Nertaro ARE-310).

(Manufacture of conductive film)
On a base material (PET (polyethylene terephthalate) base material, Tetron K 50 μm / manufactured by Teijin DuPont), the conductive film forming composition 1 is used as a screen printing machine (HP320 / Neurong) and a screen printing plate as a screen mesh BS500. / 19 (stainless steel mesh, 500 wires / inch, mesh wire diameter 19 μm, manufactured by Asada Mesh Co., Ltd.), a stripe pattern with a line width of 1 mm is printed on the substrate, and then dried at 100 ° C. for 10 minutes. A pattern-printed coating film (average thickness: 14 μm) was obtained.
Then, the electrically conductive film was obtained by baking for 1 hour at 150 degreeC on the hotplate which controlled the oxygen concentration to 50 volume ppm or less. The average thickness of the conductive film was 500 nm.

[Evaluation]
(Viscosity measurement)
By the method described above, the viscosity X of the composition for forming a conductive film measured at a shear rate of 0.1 s ⁻¹ under a temperature condition of 25 ° C. and the shear rate of 100 s ⁻¹ under a temperature condition of 25 ° C. The viscosity Y of the composition for forming a conductive film was measured.
(Screen printing aptitude)
While observing “missing” during screen printing using the composition for forming a conductive film, the shape of the stripe pattern of the formed conductive film was observed and evaluated according to the following criteria.
“A”: No “missing” and line width variation of less than 0.05 mm “B”: No “missing” and line width variation of 0.05 mm or more and less than 0.1 mm “C”: “missing” Line width variation is 0.1 mm or more and less than 0.2 mm “D”: “missing” exists, or line width variation is 0.2 mm or more “E”: “missing” exists, and the line The width variation is 0.2 mm or more. Note that “missing” means that when the composition for forming a conductive film is allowed to stand on the screen printing plate, the screen printing plate comes off before being pressed with a squeegee.
“Line width variation” means the difference between the maximum value and the minimum value obtained by measuring the line width at any 10 points in the stripe of one conductive film.

(Adhesion)
Instead of forming a stripe pattern having a line width of 1 mm, a solid film-like conductive film was produced according to the procedure described above (Manufacture of conductive film) except that a 5 cm square solid film was printed by screen printing. A cellophane tape (width 24 mm) manufactured by Nichiban Co., Ltd. was adhered to the obtained conductive film and then peeled off. The appearance of the conductive film after peeling was visually observed to evaluate the adhesion to the substrate. The evaluation criteria are as follows. In practice, it is preferably A to C.
“A”: Adhesion of the conductive film is not observed on the tape, and peeling at the interface between the conductive film and the substrate is not observed.
“B”: Adhesion of the conductive film is slightly observed on the tape, but peeling at the interface between the conductive film and the substrate is not observed.
"C": Adhesion of the conductive film is clearly seen on the tape, and the peeled area is seen in the range of less than 5% at the interface between the conductive film and the substrate.
"D": Adhesion of the conductive film is clearly seen on the tape, and the peeled area is seen in the range of 5% or more and less than 50% at the interface between the conductive film and the substrate.
“E”: The adhesion of the conductive film is clearly seen on the tape, and the peeled area is seen in the range of 50% or more at the interface between the conductive film and the substrate.

(Conductivity)
About the obtained electrically conductive film, surface resistivity was measured using the four-probe method resistivity meter, and electroconductivity was evaluated. The evaluation criteria are as follows.
“A”: surface resistivity of less than 0.5Ω / □ “B”: surface resistivity of 0.5Ω / □ or more and less than 1Ω / □ “C”: surface resistivity of 1Ω / □ or more and less than 3Ω / □ “D” ": The surface resistivity is 3 Ω / □ or more and less than 10 Ω / □" E ": The surface resistivity is 10 Ω / □ or more. Also, the volume resistivity is obtained from the film thickness and the surface resistivity of the obtained conductive film to determine the conductivity. evaluated. The evaluation criteria are as follows.
“A”: Volume resistivity is less than 50 μΩ · cm “B”: Volume resistivity is 50 μΩ · cm or more and less than 100 μΩ · cm “C”: Volume resistivity is 100 μΩ · cm or more and less than 300 μΩ · cm “D”: Volume resistance Rate is 300 μΩ · cm or more and less than 1000 μΩ · cm “E”: Volume resistivity is 1000 μΩ · cm or more

<Examples 2 to 23, Comparative Examples 1 to 6>
Except having changed the kind and usage-amount of the component which were used as shown in Table 1, according to the procedure similar to Example 1, the electrically conductive film was manufactured and various evaluation was implemented. The results are summarized in Table 1.

In Table 1, “addition amount (wt%)” represents mass% of each component with respect to the total mass of the composition for forming a conductive film.
In Table 1, “type (1: 1)” in the “solvent” column intends that the mass of water and NMP (N-methylpyrrolidone) is 1: 1.
Further, the “CuO resistance ratio (wt%)” column represents the ratio (mass%) of the content of each component (polyhydric alcohol, metal catalyst, solvent, copper particles) to the content of cupric oxide particles. . That is, the ratio (%) represents {(mass of each component / mass of cupric oxide particles) × 100}.
Moreover, the column “the amount of water relative to 100 parts by mass of the polyhydric alcohol” represents the content (parts by mass) of water relative to 100 parts by mass of the polyhydric alcohol in the composition.
Further, the “polyhydric alcohol ratio to CuO” column represents the mass ratio of the content of polyhydric alcohol to the content of cupric oxide particles (mass of polyhydric alcohol / mass of cupric oxide particles).
Further, “viscosity X / viscosity Y” intends a ratio obtained by dividing viscosity X by viscosity Y (viscosity X / viscosity Y).
Further, “> 300000” in the “Viscosity X” column intends that the viscosity exceeds 300000 mPa · s, and “> 1000” in the “Viscosity X / Viscosity Y” column intends to exceed 1000.
Furthermore, the boiling point of “trimethylolpropane” used in Table 1 was 292 ° C., and the molecular weight was 134. Further, “ethylene glycol” had a boiling point of 197 ° C. and a molecular weight of 62.

As shown in Table 1, when the composition of the present invention was used, it was confirmed that it was excellent in various effects (printability, conductivity, adhesion).
In particular, from the comparison of Examples 1 to 5, it was confirmed that the effect was more excellent when the content of cupric oxide particles was 20 to 45 mass% with respect to the total mass of the composition.
Moreover, it was confirmed from the comparison of Examples 6-10 that an effect is more excellent when the average particle diameter of a cupric oxide particle is 3 nm or more and less than 20 nm.
Moreover, from the comparison of Example 3, 11-13, when content of the water with respect to 100 mass parts of polyhydric alcohols was 20-100 mass parts, it was confirmed that an effect is more excellent.
Moreover, when content of a metal catalyst was 0.05-2.0 mass% with respect to the composition total mass from the comparison of Examples 14-18, it was confirmed that an effect is more excellent.
In addition, as shown in Examples 21 to 23, it was confirmed that the desired effect was obtained even when copper particles were included.
On the other hand, Comparative Example 1 using no polyhydric alcohol, Comparative Examples 2 and 3 in which the ratio of water to polyhydric alcohol is outside the predetermined range, Comparative Examples 4 and 5 in which the size of the cupric oxide particles is outside the predetermined range In addition, the desired effect was not obtained in Comparative Example 6 in which the viscosity of the composition was outside the predetermined range. In particular, Comparative Example 5 is an embodiment using cupric oxide particles specifically disclosed in Patent Document 1, and a desired effect was not obtained.

<Examples 24-29>
Using the composition for forming a conductive film used in Example 2, the type of the screen printing plate used was changed, and the film thickness of the conductive film was changed. Manufactured and evaluated in various ways. The results are summarized in Table 2.
In addition, the product described in the “type of screen printing plate” column in Table 2 was manufactured by Asada Mesh Co., Ltd. (using stainless steel mesh and metal wire).
“Conductivity” in Table 2 below represents the evaluation results of volume resistivity in Table 1.

As shown in Table 2, it was confirmed that the desired effect was obtained even when the screen printing conditions were changed.
In particular, from the comparison between Examples 28 and 29, it was confirmed that the effect was more excellent when the diameter of the metal wire was 10 to 30 μm.
Moreover, it was confirmed from the comparison with Example 27 and 28 that an effect is more excellent when the mesh number of a screen mesh part is 300-600 piece / inch.

Claims (16)

Cupric oxide particles having an average particle diameter of 3 to 25 nm;
Polyhydric alcohol,
Water at least,
The viscosity X measured at a shear rate of 0.1 s ⁻¹ under a temperature condition of 25 ° C. is 1000 to 200,000 mPa · s,
The ratio of the viscosity X to the viscosity Y measured at a shear rate of 100 s ⁻¹ under a temperature condition of 25 ° C. is 3.0 to 1000,
The water content relative to 100 parts by mass of the polyhydric alcohol is 0.5 to 150 parts by mass,
The composition for electrically conductive film formation for screen printing whose mass ratio of content of the said polyhydric alcohol with respect to content of the said cupric oxide particle is 0.1-2.5.   The composition for forming a conductive film according to claim 1, wherein the polyhydric alcohol includes a polyhydric alcohol having a boiling point of 250 ° C. or more and a molecular weight of 500 or less.   Furthermore, the composition for electrically conductive film formation of Claim 1 or 2 containing the metal catalyst containing the at least 1 sort (s) of metal element selected from the group which consists of a group 8-11 elements of a periodic table.   The composition for electrically conductive film formation of Claim 3 whose content of the said metal catalyst is 0.005-10.0 mass% with respect to the said cupric oxide particle total mass.   The composition for electrically conductive film formation of Claim 3 or 4 whose content of the said metal catalyst is 0.05-5.0 mass% with respect to the said cupric oxide particle total mass.   The composition for electrically conductive film formation of any one of Claims 1-5 whose average particle diameter of the said cupric oxide particle is 3 nm or more and less than 20 nm.   The composition for electrically conductive film formation of any one of Claims 1-6 whose content of the said water with respect to 100 mass parts of said polyhydric alcohols is 20-100 mass parts.   Furthermore, the composition for electrically conductive film formation of any one of Claims 1-7 containing a copper particle.   The composition for electrically conductive film formation of Claim 8 whose content of the said copper particle is 350 mass% or less with respect to the said total cupric oxide particle mass. Using the composition for forming a conductive film according to any one of claims 1 to 9, a step of forming a coating film on a substrate by a screen printing method,
Performing at least one treatment selected from the group consisting of heat treatment and light irradiation treatment on the coating film, and reducing the cupric oxide particles to form a conductive film containing metallic copper; A method for producing a conductive film.   The manufacturing method of the electrically conductive film of Claim 10 using the screen printing plate containing the screen mesh part currently formed with the metal wire by the said screen printing method.   The manufacturing method of the electrically conductive film of Claim 11 whose diameter of the said metal wire is 10-30 micrometers.   The manufacturing method of the electrically conductive film of Claim 11 or 12 whose mesh number of the said screen mesh part is 300-600 piece / inch.   The manufacturing method of the electrically conductive film of any one of Claims 10-13 whose average thickness of the said coating film is 5-50 micrometers.   The manufacturing method of the electrically conductive film of any one of Claims 10-14 whose said base material is a polyethylene terephthalate base material or a polyethylene naphthalate base material.   The manufacturing method of the electrically conductive film of any one of Claims 10-15 with which the atmosphere of the said heat processing is non-oxidative atmosphere, and the said heat processing are performed by a hotplate or inert oven.