WO2015029715A1

WO2015029715A1 - Method for producing conducting film, and conducting film

Info

Publication number: WO2015029715A1
Application number: PCT/JP2014/070610
Authority: WO
Inventors: 悠史本郷; 佑一早田
Original assignee: 富士フイルム株式会社
Priority date: 2013-08-29
Filing date: 2014-08-05
Publication date: 2015-03-05
Also published as: TW201510278A; JP2015046369A

Abstract

Provided is method for producing a conducting film which involves: a coating film formation step for forming a coating film on a resin substrate that has a pyrolysis temperature of T_D by providing a conducting film which contains copper oxide particles, copper particles and polyhydric alcohols, has a ratio of total mass of copper particles to total mass of copper oxide particles (total mass of copper particles / total mass of copper oxide particles) of 1.0-8.0, and does not contain an organic compound which is cured by heat or light; and a conducting film formation step for firing the coating film at a firing temperature of T_D-50°C or less such that the amount of organic residues in the conducting film is 1-20 mass%, and forming a conducting film that contains metallic copper. Also provided is a conducting film produced by said production method.

Description

Method for manufacturing conductive film and conductive film

The present invention relates to a method for manufacturing a conductive film. In more detail, it is related with the manufacturing method of the electrically conductive film using the composition for electrically conductive film formation containing a copper oxide particle, a copper particle, and a polyhydric alcohol.

As a method of forming a metal film on a resin base material, a dispersion of metal oxide particles is applied to the resin base material by a printing method, and heat treatment is performed to sinter the metal film or wiring on a circuit board. A technique for forming an electrical conduction site is known. Since this method is simpler, energy-saving, and resource-saving than the conventional high-heat / vacuum process (sputtering) or plating process, it is highly anticipated in the development of next-generation electronics.

For example, Patent Document 1 discloses a metal oxide dispersion containing a metal oxide having a particle diameter of less than 200 nm and a dispersion medium, wherein the dispersion medium contains a polyhydric alcohol and / or a polyether compound. A method for producing a metal thin film is disclosed, which includes applying a heat treatment after applying an oxide dispersion to a substrate. And copper oxide is described as a metal oxide and diethylene glycol is described as a polyhydric alcohol.

International Publication No. 2003/051562

When a composition for forming a conductive film containing copper oxide fine particles is applied onto a resin substrate and subjected to a baking treatment, not only energy saving but also versatility of the resin substrate requires a low temperature baking treatment. ing. However, at a firing temperature of 200 ° C. or less at which polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) can be used as a resin base material, the reduction of copper oxide and the oxide film on the copper surface is insufficient. It was difficult to obtain a conductive film having good conductivity and adhesion while suppressing warping of the resin base material.

When the present inventors examined the manufacturing method of the electrically conductive film disclosed by patent document 1, although the electroconductivity of the obtained electrically conductive film reached the level currently requested | required, the adhesiveness of an electrically conductive film is a required level. The warpage of the resin base material could not be suppressed.

Then, in view of the said situation, this invention aims at providing the manufacturing method of the electrically conductive film which can form the electrically conductive film which does not generate | occur | produce the curvature of a resin base material but is excellent in adhesiveness and electroconductivity. .
Moreover, an object of this invention is to provide the electrically conductive film manufactured using this manufacturing method of an electrically conductive film.

As a result of earnestly examining the problems of the prior art, the present inventors have found that the mass ratio of the copper particles to the copper oxide particles in the conductive film forming composition, the firing temperature in the conductive film production process, and the conductive film It has been found that the above problem can be solved by controlling the amount of organic residue.
That is, it has been found that the above object can be achieved by the following configuration.

(1) on a resin substrate having a thermal decomposition temperature T _D, and the copper oxide particles, and copper particles, containing the polyhydric alcohol, the total weight ratio of the value of the copper particles to the total weight of copper oxide particles ( Coating that forms a coating film by applying a conductive film that has a total mass of copper particles / total mass of copper oxide particles of 1.0 or more and 8.0 or less and that does not include an organic compound that is cured by heat or light. A film forming step;
The coating film is subjected to a firing treatment at a firing temperature of T _D −50 ° C. or less so that the amount of organic residue in the conductive film is 1% by mass or more and 20% by mass or less. The manufacturing method of an electrically conductive film provided with the electrically conductive film formation process formed.
(2) The manufacturing method of the electrically conductive film as described in (1) whose baking temperature is 220 degrees C or less.
(3) The manufacturing method of the electrically conductive film as described in (1) or (2) whose baking temperature is 200 degrees C or less.
(4) The method for producing a conductive film according to any one of (1) to (3), wherein the amount of organic residue is 5% by mass or more and 10% by mass or less.
(5) The ratio of the total mass of copper particles to the total mass of copper oxide particles (total mass of copper particles / total mass of copper oxide particles) is 2.0 or more and 6.0 or less, (1) to ( The method for producing a conductive film according to any one of 4).
(6) The value of the ratio of the total mass of polyhydric alcohol to the total mass of copper oxide particles (total mass of polyhydric alcohol / total mass of copper oxide particles) is 1.0 or more and 4.0 or less, (1) The method for producing a conductive film according to any one of (5) to (5).
(7) The method for producing a conductive film according to any one of (1) to (6), wherein the resin base material is a polyethylene terephthalate (PET) base material or a polyethylene naphthalate (PEN) base material.
(8) The method for producing a conductive film according to any one of (1) to (7), wherein the polyhydric alcohol is ascorbic acid or dihydroxyacetone.
(9) The method for producing a conductive film according to any one of (1) to (8), wherein the average particle diameter of the copper oxide particles is 20 nm or more and 50 nm or less.
(10) The method for producing a conductive film according to any one of (1) to (9), wherein an average particle diameter of the copper particles is 0.1 μm or more and 10 μm or less.
(11) The method for producing a conductive film according to any one of (1) to (10), wherein the baking treatment is performed in an inert gas atmosphere.
(12) A conductive film produced by the method for producing a conductive film according to any one of (1) to (11).

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electrically conductive film which can form the electrically conductive film excellent in adhesiveness and electroconductivity can be provided, without generating the curvature of a resin base material.
Moreover, according to this invention, the electrically conductive film manufactured using the manufacturing method of this electrically conductive film can also be provided.

Below, the manufacturing method of the electrically conductive film of this invention and the suitable aspect of the composition for electrically conductive film formation are demonstrated in detail.
First, the feature point compared with the prior art of this invention is explained in full detail.

One of the features of the present invention is that the amount of the organic residue in the conductive film is 1 mass at a firing temperature of T _D -50 ° C. or less with respect to the coating film formed on the resin substrate having the thermal decomposition temperature T _D. It is in the point which performs a baking process so that it may become 20 to 20 mass%. By performing the baking treatment under these conditions, a conductive film excellent in adhesion and conductivity can be formed on the resin base material without causing warpage of the resin base material.
Another feature of the present invention is that the composition for forming a conductive film contains copper oxide particles and copper particles, the value of the ratio of the total mass of copper particles to the total mass of copper oxide particles (total mass of copper particles). / The total mass of the copper oxide particles) is 1.0 to 8.0. By containing the copper oxide particles and the copper particles under these conditions, a conductive film having excellent adhesion and conductivity can be formed on the resin base material without causing warpage of the resin base material.

Below, the various components (copper oxide particle, copper particle, polyhydric alcohol, etc.) of the composition for electrically conductive film formation are explained in full detail first, and the manufacturing method of an electrically conductive film is explained in full detail after that.
In the present invention, when “X or more and Y or less” or “X to Y” is described for a certain numerical range, X and Y are included in the numerical range.

<Copper oxide particles>
The composition for forming a conductive film contains copper oxide particles. The copper oxide of the copper oxide particles is reduced to metallic copper by a baking treatment, and constitutes metallic copper in the conductive film together with copper particles described later.

The average particle diameter of the copper oxide particles is not particularly limited, but is preferably in the range of 10 nm to 100 nm, and more preferably in the range of 20 nm to 50 nm.
When the average particle diameter of the copper oxide particles is 10 nm or more, the activity on the particle surface does not become too high, the dispersion becomes easy in the composition, and the handleability and storage stability are excellent. Further, when the average particle diameter of the copper oxide particles is 100 nm or less, the composition can be used as an ink-jet ink composition, and it is easy to form a pattern such as wiring by a printing method, and the composition is made conductive. At this time, since the active surface spreads, reduction to metallic copper is likely to occur, and the conductivity of the obtained conductive film becomes better. When the average particle diameter of the copper oxide particles is in the range of 20 nm to 50 nm, the conductivity of the obtained conductive film is further improved.

The “copper oxide” in the present invention is a compound that substantially does not contain copper that has not been oxidized. Specifically, in a crystal analysis by X-ray diffraction, a peak derived from copper oxide is detected, and is derived from a metal. Refers to a compound for which no peak is detected. The phrase “substantially free of copper” means that the copper content is 1% by mass or less in the total mass of the copper oxide particles.

Further, as the copper oxide, copper oxide (I) or copper oxide (II) is preferable, and copper (II) oxide is more preferable because it is available at a low cost and has excellent stability in the air. .

As a copper oxide particle, the well-known copper oxide particle used for the composition for electrically conductive film formation can be used. For example, as the copper oxide particles, NanoTek ^(R) CuO, NanoTek ^(R) Slurry CuO, manufactured by CI Kasei Co., Ltd., NO-0004-HP, NO-0031-HP, manufactured by Sigma Aldrich, manufactured by Sigma Aldrich Copper (II) oxide nanopowder and the like can be used.

In addition, the average particle diameter of the copper oxide particle in this invention points out an average primary particle diameter. The average particle diameter is determined by measuring the particle diameter (diameter) of at least 50 or more copper oxide particles by observation with a transmission electron microscope (TEM) or scanning electron microscope (SEM) and arithmetically averaging them. In the observation diagram, when the shape of the copper oxide particles is not a perfect circle, the major axis is measured as the diameter.

<Copper particles>
The conductive film-forming composition contains copper particles. The copper particles constitute metal copper in the conductive film together with the metal copper produced by reducing the copper oxide of the copper oxide particles described above by the firing treatment during film formation.

The average particle diameter of the copper particles is not particularly limited, but is preferably in the range of 0.1 μm to 20 μm, and more preferably in the range of 0.1 μm to 10 μm.
The electroconductivity of the electrically conductive film obtained as the average particle diameter of a copper particle is 0.1 micrometer or more is more excellent. Moreover, it becomes easy to form fine wiring as the average particle diameter of a copper particle is 20 micrometers or less. It is more preferable that the average particle diameter of the copper particles is in the range of 0.1 μm or more and 10 μm or less because the adhesion and conductivity of the conductive film are further improved.

As a copper particle, the well-known metal copper particle used for the composition for electrically conductive film formation can be used. For example, flake copper powders 1050YP, 1100YP, 1200YP, 1400YP, MA-C08JF, MA-C025KFD, MA-C05KFD, fine atomized copper powder MA-C015K, MA-C02K, MA- C03K, MA-C04K, MA-C08J, MA-CJU, wet copper powder 1030Y, 1050Y, 1100Y, 1200N, 1400Y, 1400YM, 1110, and the like can be used.

In addition, the average particle diameter of the copper particle in this invention points out an average primary particle diameter. The average particle size is obtained by measuring the particle size (diameter) of at least 50 copper particles by observation with a transmission electron microscope (TEM) or scanning electron microscope (SEM) 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.

<Polyhydric alcohol>
The composition for forming a conductive film contains a polyhydric alcohol. Since the polyhydric alcohol has a reducing property, the copper oxide in the conductive film is reduced and converted to metallic copper during the baking treatment.
The polyhydric alcohol is not particularly limited as long as it is a compound having two or more hydroxy groups in one molecule. For example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2 -Butanediol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, octanediol, 1,1,1- Trishydroxymethylethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexanetriol, 1,2,4-butanetriol, ascorbic acid Erythorbic acid, sugar alcohols, monosaccharides, disaccharides, trisaccharides and the like.

Sugar alcohols include glycerin-containing tritols, erythritol, tetritols such as threitol, pentitols such as arabinitol, xylitol, ribitol (aditol), iditol, galactitol (dulcitol), glucitol (sorbitol), mannitol, etc. Hexitols, boremitol, heptitols such as perseitol, and the like.

Monosaccharides include glyceraldehyde, threose, erythrose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose and other aldoses, dihydroxyacetone, erythrulose, xylulose, ribulose And ketoses such as psicose, fructose, sorbose, tagatose, sedoheptulose, and coliose.

Examples of disaccharides include non-reducing sugars such as sucrose, trehalose, isotrehalose (β, β-trehalose), neotrehalose (α, β-trehalose), galactosucrose, lactulose, lactose, maltose, cellobiose, cordobiose, nigerose, iso Examples thereof include reducing sugars such as maltose, sophorose, laminaribiose, gentibiose, turanose, maltulose, palatinose, gentibiurose, mannobiose, melibiose, melibiose, neolactoses, sylabiose, rutinose, rutinulose, vicyanose, xylobiose, and primeverose.

Examples of the trisaccharide include nigerotriose, maltotriose, melezitose, maltotriurose, raffinose, and kestose.

In addition, the polyhydric alcohol includes an enantiomer when the enantiomer is present. For example, ascorbic acid includes L-ascorbic acid and D-ascorbic acid, and glucose includes D-glucose, L-glucose and the like. In addition, the polyhydric alcohol includes a totomer if present. For example, glucose includes α-glucopyranose, β-glucopyranose, α-glucofuranose, β-glucofuranose, and the like.

<Solvent and other ingredients>
The composition for forming a conductive film comprises, as necessary, a solvent (dispersion medium) and various additives (leveling agent, coupling agent, viscosity modifier, antioxidant, in addition to copper oxide particles, copper particles and polyhydric alcohol. , Other adhesive components, etc.) may be included within a range not impairing the effects of the present invention. In particular, in order to obtain a composition having appropriate fluidity, it is preferable to contain a solvent.

Examples of the solvent include one selected from water, alcohols, ethers, esters, hydrocarbons, and aromatic hydrocarbons, or a compatible mixture of two or more.

Since the solvent is excellent in compatibility with polyhydric alcohols, water, water-soluble alcohols (limited to monohydric alcohols), alkyl ethers derived from water-soluble alcohols (one having 1 or less hydroxy group in one molecule) However, alkyl esters derived from water-soluble alcohols (limited to those having 1 or less hydroxy group in one molecule) or mixtures thereof are preferably used.

As water, what has the purity of the level of ion-exchange water at least is preferable.
Specific examples of water-soluble alcohols (limited to monohydric alcohols) include methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, cyclohexanol, 1-heptanol, and 1-octanol. 1-nonanol, 1-decanol, glycidol, methylcyclohexanol, 2-methyl-1-butanol, 3-methyl-2-butanol, 4-methyl-2-pentanol, isopropyl alcohol, 2-ethylbutanol, 2- Examples include ethylhexanol, 2-octanol, terpineol, dihydroterpineol, 2-methoxyethanol, 2-ethoxyethanol, 2-n-butoxyethanol, carbitol, ethyl carbitol, n-butyl carbitol, diacetone alcohol, etc. .
Among these, at least one selected from methanol, 2-methoxyethanol and isopropyl alcohol is preferable because the boiling point is not too high and it is difficult to remain after formation of the conductive film.

Specific examples of alkyl ethers derived from water-soluble alcohols (limited to those having one or less hydroxy group in one molecule) include diethyl ether, diisobutyl ether, dibutyl ether, methyl-t-butyl ether, and methylcyclohexyl ether. And diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like.
Among these, at least one selected from diethyl ether, diethylene glycol dimethyl ether, and tetrahydrofuran is preferable because the boiling point is not too high and it is difficult to remain after forming the conductive film.

Specific examples of alkyl esters derived from water-soluble alcohols (limited to those having 1 or less hydroxy group in one molecule) include methyl formate, ethyl formate, butyl formate, methyl acetate, ethyl acetate, butyl acetate, Examples include methyl propionate, ethyl propionate, butyl propionate, and γ-butyrolactone.
Among these, at least one selected from methyl formate, ethyl formate, and methyl acetate is preferable because it does not have a high boiling point and hardly remains after formation of the conductive film.

Among the solvents, since the boiling point is not too high, it is particularly preferable to use water or a water-soluble alcohol (limited to monovalent alcohol) as the main solvent. The main solvent is a solvent having the highest content in the solvent.

[Method for producing composition for forming conductive film]
The composition for forming a conductive film of the present invention contains copper oxide particles, copper particles, a polyhydric alcohol, and optionally a solvent and other components, but does not contain an organic compound that is cured by heat or light.

The organic compound that is cured by heat or light refers to an organic compound that is cured by heating or an organic compound that is cured by light irradiation. Light irradiation includes electromagnetic wave irradiation.
As an organic compound which hardens | cures by heating, a thermosetting resin is mentioned, for example. Specific examples of the thermosetting resin include phenol resin, epoxy resin, melamine resin, urea resin (urea resin), unsaturated polyester resin, alkyd resin, polyurethane, and thermosetting polyimide.
As an organic compound hardened | cured by light irradiation, photocurable resin is mentioned, for example. Examples of the photocurable resin include resins in which polymerization of monomers and oligomers proceeds by activation of a photopolymerization initiator.
Further, “does not contain” means that the ratio of the organic compound cured by heat or light to the total of copper oxide particles, copper particles and polyhydric alcohol is 1% by mass or less, and is 0% by mass. It is preferable.

The content of the copper particles in the conductive film forming composition is such that the ratio of the total mass of the copper particles to the total mass of the copper oxide particles (total mass of the copper particles / total mass of the copper oxide particles) is 1.0 or more. The amount is 8.0 or less, preferably 2.0 or more and 6.0 or less. When the value of the ratio of the total mass of the copper particles to the total mass of the copper oxide particles is within this range, the conductive path is increased, so that the conductivity of the obtained conductive film is excellent, and the conductive film forming composition In order to improve fluidity | liquidity, it is excellent in the printability of the composition for electrically conductive film formation. When the value of the ratio of the total mass of the copper particles to the total mass of the copper oxide particles is less than 1.0, the warp of the resin base material cannot be suppressed during the firing treatment, and when it exceeds 8.0, the produced conductivity The adhesion and conductivity of the film do not reach the required levels.

The content of the polyhydric alcohol in the composition for forming a conductive film is not particularly limited, but the ratio of the total mass of the polyhydric alcohol to the total mass of the copper oxide particles (total mass of polyhydric alcohol / copper oxide particles) The total mass) is preferably 0.5 to 4.5 and more preferably 1.0 to 4.0. When the value of the ratio of the total mass of the polyhydric alcohol to the total mass of the copper oxide particles is within this range, the copper oxide can be sufficiently reduced, and the conductivity of the obtained conductive film is more excellent.

In the case where the composition for forming a conductive film contains a solvent, the content is not particularly limited, but the increase in the viscosity of the composition for forming a conductive film is suppressed, and the composition for forming a conductive film is superior in terms of handleability. 10 mass% or more and 60 mass% or less are preferable with respect to a total mass, and 20 mass% or more and 50 mass% or less are more preferable.

The viscosity of the conductive film forming composition is preferably adjusted to a viscosity suitable for printing applications such as inkjet and screen printing. When inkjet discharge is performed, 1 to 50 cP is preferable, and 1 to 40 cP is more preferable. When screen printing is performed, it is preferably from 1,000 to 100,000 cP, more preferably from 10,000 to 80,000 cP.

The method for preparing the conductive film forming composition is not particularly limited, and a known method can be adopted. For example, after adding copper oxide particles, copper particles, polyhydric alcohol, and optionally a solvent and other components in a solvent, an ultrasonic method (for example, treatment with an ultrasonic homogenizer), a mixer method, 3 A composition can be obtained by dispersing the components by a known means such as the present roll method or ball mill method.

[Method for producing conductive film]
The manufacturing method of the electrically conductive film of this invention has a coating-film formation process and an electrically conductive film formation process at least. Below, each process is explained in full detail.

<Coating film formation process>
A coating-film formation process is a process of providing the composition for electrically conductive film formation mentioned above on a resin base material, and forming a coating film. The coating film before baking processing is obtained by this process. You may dry a coating film before the electrically conductive film formation process mentioned later.

As the resin base material used in this step, known materials can be used. Resin base materials include low density polyethylene resin base materials, high density polyethylene resin base materials, ABS resin base materials, acrylic resin base materials, styrene resin base materials, vinyl chloride resin base materials, polyester resin base materials (polyethylene terephthalate ( PET) base material, polyethylene naphthalate (PEN) base material), polyacetal resin base material, polysulfone resin base material, polyetherimide resin base material (polyimide resin base material), polyether ketone resin base material, cellulose derivative base material, Paper-phenolic resin substrate (paper phenolic resin substrate), paper-epoxy resin substrate (paper epoxy resin substrate), paper-polyester resin substrate (paper polyester resin substrate), glass cloth-epoxy resin substrate ( Glass epoxy resin substrate), glass cloth-polyimide resin substrate (glass polyimide resin substrate), or glass Scan cloth - fluororesin base material made of (Garasufu' containing resin base material) and the like. Among these, a polyethylene terephthalate (PET) base material or a polyethylene naphthalate (PEN) base material is preferable, and a polyethylene terephthalate (PET) base material is more preferable.

The thermal decomposition temperature T _D of the resin base material is a 10% decomposition temperature (° C.), specifically, using a differential thermogravimetric simultaneous measurement device (TG / DTA), thermogravimetric in a nitrogen atmosphere Is the temperature at the time of 10% weight reduction when measured (10% weight reduction temperature) (° C.). In general, even with the same kind of resin, the molecular weight and molecular weight distribution, degree of branching, a difference in thermal decomposition behavior, such as by cross-linking density occurring, there is a case where T _D is different.

The method for applying the conductive film-forming composition onto the resin substrate is not particularly limited, and a known method can be employed. For example, coating methods such as a screen printing method, a dip coating method, a spray coating method, a spin coating method, and an ink jet method can be used.
The shape of application is not particularly limited, and may be a planar shape covering the entire surface of the resin base material or a pattern shape (for example, a wiring shape or a dot shape).
The coating amount of the composition for forming a conductive film on a resin substrate may be appropriately adjusted according to the desired thickness of the conductive film. Usually, the thickness (thickness) of the coating film is 0.01 to 1000 μm is preferable, 0.1 to 100 μm is more preferable, 0.1 to 50 μm is more preferable, and 1 to 30 μm is even more preferable.

<Drying process>
This step is a step in which the formed coating film is dried to remove the solvent. If desired, this step can be performed after the above-described coating film forming step and before the conductive film forming step described later.
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. It is preferable in terms of adhesion.
As a method for the drying treatment, for example, it can be carried out by heating using a hot air dryer or the like, and it is preferable to carry out the drying treatment at a temperature lower than the firing temperature described later. Specifically, the drying temperature is preferably 40 ° C. or higher and lower than 200 ° C., more preferably 50 ° C. or higher and lower than 150 ° C.
In the present invention, the drying treatment can be performed in an inert gas atmosphere or in the air, but is preferably performed in an inert gas atmosphere.

<Conductive film formation process>
In the conductive film forming step, the amount of organic residue in the conductive film is 1% by mass or more and 20% by mass or less at a firing temperature of T _D −50 ° C. or less on the coating film formed on the resin substrate by the coating film forming step. In this step, the conductive film is formed by firing for a period of time. Here, T _D is the thermal decomposition temperature of the resin substrate.
The heating means for firing is not particularly limited, and known heating means such as an oven and a hot plate can be used. In the present invention, the conductive film can be formed by performing the baking treatment at a relatively low temperature, and therefore, the process cost is low.
By performing the baking treatment, the polyhydric alcohol works as a reducing agent, and the copper oxide is reduced and converted to metallic copper. More specifically, by subjecting the copper oxide particles in the coating film to reduction by the firing treatment, the metal copper particles promote the adhesion and fusion between the copper particles to form grains, and further the grains. The copper films are formed by bonding and fusing together.

Calcination treatment temperature (sintering temperature) _is not particularly limited as long as T D -50 ° C. or _less, as long as it does not exceed T D -50 ° C., preferably 220 ° C. or less, more preferably 200 ° C. or less. The lower limit of the firing temperature is a temperature capable of converting by reducing copper oxide in the conductive film forming composition to metallic copper, and is not particularly limited as long as T _D -50 ° C. or less, T _D - As long as it does not exceed 50 ° C, 150 ° C or higher is preferable, and 180 ° C or higher is more preferable.

The time for the baking treatment (baking time) is not particularly limited as long as the amount of the organic matter residue in the conductive film is 1% by mass or more and 20% by mass or less, but the time for 5% by mass or more and 10% by mass or less is preferable. . The “organic residue amount” is the amount of organic matter (unit: mass%) remaining in the conductive film after the baking treatment, and the differential thermal and thermogravimetric simultaneous measurement device (TG / DTA) for the conductive film after the baking treatment. Thus, it can be calculated from the weight reduction amount of the organic matter measured by heating to 500 ° C. in a nitrogen atmosphere.

In the present invention, the baking treatment can be performed in an inert gas atmosphere or in the air, but is preferably performed in an inert gas atmosphere.

[Conductive film]
By carrying out the above steps, a conductive film (metal copper film) containing metal copper is obtained.
The film thickness (thickness) of the conductive film is not particularly limited, and an optimum film thickness is appropriately adjusted according to the intended use. Among these, from the viewpoint of printed circuit board use, 0.01 to 1000 μm is preferable, 0.1 to 100 μm is more preferable, 0.1 to 50 μm is further preferable, and 1 to 30 μm is even more preferable.
The film thickness is a value (average value) obtained by measuring three or more thicknesses at arbitrary points on the conductive film and arithmetically averaging the values.
The conductive film volume resistivity can be calculated by multiplying the obtained surface resistivity by the film thickness after measuring the surface resistivity of the conductive film by the four-probe method.

The conductive film may be provided on the entire surface of the resin 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 for obtaining a patterned conductive film, the above conductive film-forming composition is applied to a resin base material in a pattern, and the above heat treatment is performed, or the conductive film provided on the entire surface of the resin base material is patterned. And a method of etching into a shape.
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 material of the insulating film is not particularly limited. For example, epoxy resin, glass epoxy resin, aramid resin, crystalline polyolefin resin, amorphous polyolefin resin, fluorine-containing resin (polytetrafluoroethylene, perfluorinated polyimide, perfluorinated) Amorphous resin), polyimide resin, polyether sulfone resin, polyphenylene sulfide resin, polyether ether ketone resin, liquid crystal resin, and the like.
Among these, from the viewpoints of adhesion, dimensional stability, heat resistance, electrical insulation, and the like, it is preferable to contain an epoxy resin, a polyimide resin, or a liquid crystal resin, and more preferably an epoxy resin. Specific examples include ABF GX-13 manufactured by Ajinomoto Fine Techno Co., Ltd.

The solder resist, which is a kind of insulating layer material used for wiring protection, is described in detail in, for example, Japanese Patent Application Laid-Open No. 10-204150 and Japanese Patent Application Laid-Open No. 2003-222993. These materials can also be applied to the present invention if desired. As the solder resist, commercially available products may be used. Specific examples include PFR800 manufactured by Taiyo Ink Manufacturing Co., Ltd., PSR4000 (trade name), SR7200G manufactured by Hitachi Chemical Co., Ltd., and the like.

The resin base material (resin base material with a conductive film) having the conductive film obtained above can be used for various applications. For example, a flexible printed circuit board, a rigid flexible printed circuit board, a rigid printed circuit board, TFT, RFID, etc. are mentioned.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[Example 1]
<Preparation of composition for forming conductive film>
Copper oxide particles 1 (average particle size of 40 nm; manufactured by CI Kasei Co., Ltd., NanoTek ^(R) CuO) (100 parts by mass) and copper particles 1 (average particle size of 3 μm; manufactured by Mitsui Metal Mining Co., Ltd., flaky copper powder 1200YP) ( 250 parts by mass), ascorbic acid (300 parts by mass), and water (ultra pure water) (500 parts by mass) were added, and the mixture was rotated for 5 minutes with a rotating / revolving mixer (manufactured by THINKY, Awatori Kentaro ARE-310). The composition for electrically conductive film formation was obtained by processing.
<Preparation of conductive film>
On the PET substrate (T _D = 320 ° C .; manufactured by FUJIX OHP FILM, manufactured by FUJIFILM Business Supply Co., Ltd.), the obtained composition for forming a conductive film is applied in a stripe shape (L / S = 1 mm / 1 mm), and then By drying at 100 ° C. for 10 minutes, a coating film on which the conductive film-forming composition layer was printed was obtained. Then, using an RTA sintering apparatus (Allwin21, AccuThermo), the sample is heated to 180 ° C. and held for a time when the amount of organic residue in the conductive film becomes 5% by mass, and then cooled to 1040 ° C. and the sample is taken out. Thus, a conductive film was obtained.
Here, the amount of organic matter residue is calculated from the weight reduction amount of the organic matter measured by heating the conductive film after baking treatment to 500 ° C. in a nitrogen atmosphere with a differential thermogravimetric simultaneous measurement device (TG / DTA). did.

<Evaluation of warpage of resin substrate>
About the obtained resin base material with a conductive film (hereinafter referred to as “sample” in this evaluation item), between the surface plate and the side of the sample by the method described in 5.22 of JIS C 6481: 1996. Was measured in units of 0.1 mm. The evaluation criteria are as follows. In practice, A evaluation or B evaluation is desirable. The result of evaluation is shown in the corresponding column of Table 1.
A: The distance between the surface plate and the side of the sample is 0.5 mm or less.
B: The distance between the surface plate and the side of the sample is more than 0.5 mm and not more than 1.0 mm.
C: The distance between the surface plate and the side of the sample is more than 1.0 mm and not more than 2.0 mm.
D: The distance between the surface plate and the side of the sample is more than 2.0 mm and 5.0 mm or less.
E: The distance between the surface plate and the side of the sample is more than 5.0 mm.

<Evaluation of adhesion of conductive film>
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. The evaluation criteria are as follows. In practice, A evaluation or B evaluation is desirable. The result of evaluation is shown in the corresponding column of Table 1.
A: Adhesion of the conductive film is not observed on the tape, and peeling at the interface between the conductive film and the resin 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 resin substrate is not observed.
C: Adhesion of the conductive film is clearly seen on the tape, and peeling at the interface between the conductive film and the resin substrate is observed in an area of less than 5%.
D: Adhesion of the conductive film is clearly seen on the tape, and peeling at the interface between the conductive film and the resin substrate is seen in an area of 5% or more and less than 50%.
E: Adhesion of the conductive film is clearly seen on the tape, and peeling at the interface between the conductive film and the resin substrate is seen in an area of 50% or more.

<Evaluation of conductivity of conductive film>
About the obtained electrically conductive film, volume resistivity was measured using the four-probe method resistivity meter, and electroconductivity was evaluated. The evaluation criteria are as follows. In practice, A evaluation or B evaluation is desirable. The result of evaluation is shown in the corresponding column of Table 1.
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 1000 μΩ · cm.
D: Volume resistivity is 1000 μΩ · cm or more.

[Examples 2 and 3]
Except for the point that the firing temperature was changed to the temperature shown in Table 1, a conductive film was prepared in the same manner as in Example 1, and the warpage of the resin substrate, the adhesion and the conductivity of the conductive film were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Example 4]
A conductive film was prepared in the same manner as in Example 1 except that a PEN substrate (manufactured by Teijin DuPont Films, Teonex, T _D = 410 ° C.) was used instead of the PET substrate. The adhesion and conductivity of the conductive film were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Examples 5 and 6]
A conductive film was prepared in the same manner as in Example 1 except that the heating time was changed so that the amount of organic residue was the amount shown in Table 1, and the warpage of the resin substrate, the adhesion and the conductivity of the conductive film were determined. evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Example 7]
Example 1 except that copper oxide particles 2 (average particle diameter 80 nm; manufactured by Iritech, NO-0031-HP) (100 parts by mass) was used instead of copper oxide particles 1 (100 parts by mass). Similarly, a conductive film was prepared, and the warpage of the resin base material, the adhesion and the conductivity of the conductive film were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Examples 8 and 9]
Except for the point that the content of the copper particles 1 was changed to the amount shown in Table 1, a conductive film was prepared in the same manner as in Example 1, and the warpage of the resin substrate, the adhesion and the conductivity of the conductive film were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Example 10]
Conductiveness was conducted in the same manner as in Example 1 except that copper particles 2 (average particle diameter 17 μm; manufactured by Mitsui Mining & Smelting Co., Ltd., fine atomized copper powder MA-CJF) was used instead of copper particles 1 (250 parts by mass). A film was prepared, and the warp of the resin base material, the adhesion of the conductive film, and the conductivity were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Example 11]
A conductive film was produced in the same manner as in Example 1 except that dihydroxyacetone (300 parts by mass) was used in place of ascorbic acid (300 parts by mass), and the warp of the resin base material, the adhesion of the conductive film and Conductivity was evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Examples 12 and 13]
Except for the point that the content of ascorbic acid was changed to the amount shown in Table 1, a conductive film was prepared in the same manner as in Example 1, and the warpage of the resin substrate, the adhesion and the conductivity of the conductive film were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Examples 14 and 15]
A conductive film was produced in the same manner as in Example 1 except that the baking treatment was performed in an N ₂ (nitrogen) atmosphere or in the air as shown in Table 1, and the warpage of the resin base material, the adhesion of the conductive film, and Conductivity was evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Comparative Example 1]
Except for the point that the firing temperature was 290 ° C., a conductive film was prepared in the same manner as in Example 1, and the warpage of the resin substrate, the adhesion and the conductivity of the conductive film were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Comparative Examples 2 and 3]
A conductive film was prepared in the same manner as in Example 1 except that the heating time was changed so that the amount of organic residue was the amount shown in Table 1, and the warpage of the resin substrate, the adhesion and the conductivity of the conductive film were determined. evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Comparative Example 4]
Except the point which does not contain a copper oxide particle, the electrically conductive film was obtained like Example 1, and the curvature of the resin base material, the adhesiveness of the electrically conductive film, and electroconductivity were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Comparative Example 5]
Except the point which does not contain a copper particle, the electrically conductive film was obtained like Example 1, and the curvature of the resin base material, the adhesiveness of the electrically conductive film, and electroconductivity were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Comparative Example 6]
A conductive film was obtained in the same manner as in Example 1 except that diethylene glycol (300 g) was used instead of copper particles and ascorbic acid (300 parts by mass), and the warp of the resin substrate, the conductive film The adhesion and electrical conductivity of were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

[Comparative Examples 7 and 8]
Except for the point that the content of the copper particles 1 was changed to the amount shown in Table 1, a conductive film was prepared in the same manner as in Example 1, and the warpage of the resin substrate, the adhesion and the conductivity of the conductive film were evaluated. The result of evaluation is shown in the corresponding column of Table 1.

Examples 1 to 15 were superior in all of the warp of the resin base material, the adhesion of the conductive film and the conductivity, but the conductive films of Comparative Examples 1 to 8 were the warp of the resin base material and the adhesion of the conductive film. And at least one of the conductivity was inferior.

According to the comparison of Examples 1 to 3, it was confirmed that the lower the firing temperature, the lower the warp of the resin base material.

According to the comparison between Examples 1 and 6, it is confirmed that Example 1 in which the amount of organic residue is 5% by mass or more is more excellent in adhesion of the conductive film than Example 6 in which the amount is less than 5% by mass. did it.
Further, according to the comparison between Examples 1 and 5, Example 1 in which the amount of organic residue is 10% by mass or less is more excellent in conductivity of the conductive film than Example 5 exceeding 10% by mass. It could be confirmed.

According to the comparison between Examples 1 and 7, Example 1 in which the average particle diameter of the copper oxide particles is in the range of 20 nm or more and 50 nm or less is more conductive than that of Example 7 that is outside the range. Was confirmed to be superior.

From the comparison of Examples 1 and 8, Example 1 in which the value of the ratio of the total mass of copper particles to the total mass of copper oxide particles (total mass of copper particles / total mass of copper oxide particles) is 2.0 or more is Compared with Example 8 which is less than 2.0, the curvature of the resin base material was suppressed and it has confirmed that the electroconductivity of the electrically conductive film was more excellent.
Moreover, from the comparison of Examples 1 and 9, the value of the ratio of the total mass of the copper particles to the total mass of the copper oxide particles (total mass of the copper particles / total mass of the copper oxide particles) is 6.0 or less. It was confirmed that 1 was more excellent in conductivity than Example 8 which was over 6.0.

From the comparison of Examples 1 and 10, Example 1 in which the average particle diameter of the copper particles is in the range of 0.1 μm or more and 10 μm or less is more adhesive than the Example 10 which is out of the range. It was confirmed that the conductivity was more excellent.

From the comparison of Examples 1, 12 and 13, the value of the ratio of the total mass of polyhydric alcohol to the total mass of copper oxide particles (total mass of polyhydric alcohol / total mass of copper oxide particles) is 1.0 or more. It was confirmed that Example 1, which was within the range of 0 or less, was more excellent in the conductivity of the conductive film than Examples 12 and 13, which were outside the range.

From the comparison of Examples 1, 14 and 15, Examples 1 and 14 in which the baking treatment was performed in an inert gas atmosphere were more effective than those in Example 15 in which the baking treatment was performed in the atmosphere. It was confirmed that the conductivity was more excellent.

Claims

On a resin substrate having a thermal decomposition temperature T D, and the copper oxide particles, and copper particles, containing the polyhydric alcohol, the value of the ratio of the total weight of the copper particles to the total weight of the copper oxide particles is 1 A coating film forming step of forming a coating film by applying a composition for forming a conductive film that is not less than 0.0 and not more than 8.0 and does not contain an organic compound that is cured by heat or light;
Conductive treatment is performed on the coating film at a firing temperature of T D −50 ° C. or less so that the amount of organic residue in the conductive film is 1% by mass or more and 20% by mass or less, and the conductive film contains metallic copper. The manufacturing method of an electrically conductive film provided with the electrically conductive film formation process of forming.
The manufacturing method of the electrically conductive film of Claim 1 whose said baking temperature is 220 degrees C or less.
The manufacturing method of the electrically conductive film of Claim 1 or 2 whose said baking temperature is 200 degrees C or less.
The method for producing a conductive film according to any one of claims 1 to 3, wherein the amount of the organic substance residue is 5 mass% or more and 10 mass% or less.
The method for producing a conductive film according to any one of claims 1 to 4, wherein a value of a ratio of a total mass of the copper particles to a total mass of the copper oxide particles is 2.0 or more and 6.0 or less.
The method for producing a conductive film according to any one of claims 1 to 5, wherein a value of a ratio of a total mass of the polyhydric alcohol to a total mass of the copper oxide particles is 1.0 or more and 4.0 or less.
The method for producing a conductive film according to any one of claims 1 to 6, wherein the resin base material is a polyethylene terephthalate base material or a polyethylene naphthalate base material.
The method for producing a conductive film according to any one of claims 1 to 7, wherein the polyhydric alcohol is ascorbic acid or dihydroxyacetone.
The method for producing a conductive film according to any one of claims 1 to 8, wherein an average particle diameter of the copper oxide particles is 20 nm or more and 50 nm or less.
10. The method for producing a conductive film according to claim 1, wherein an average particle diameter of the copper particles is 0.1 μm or more and 10 μm or less.
The method for producing a conductive film according to any one of claims 1 to 10, wherein the baking treatment is performed in an inert gas atmosphere.
A conductive film produced by the method for producing a conductive film according to any one of claims 1 to 11.