TW201510278A - Method for producing electroconductive film and electroconductive film - Google Patents

Abstract

A method for producing an electroconductive film and an electroconductive film produced by using the same are provided. The method for producing the electroconductive film includes: a coating film forming step, wherein the electroconductive film forming composition is applied to a resin substrate with a heat decomposition temperature TD to form the coating film, the electroconductive film forming composition includes copper oxide particles, copper particles, and polyhydric alcohol, and a ratio of a total mass of the copper particles to a total mass of the copper oxide particles is 1.0 or more and 8.0 or less, and the electroconductive film is free of an organic compound curable by heating or lighting; an electroconductive film forming step, wherein the coating film is subjected to a calcination treatment to form an electroconductive film with metal copper as the organic substance residual amount of the electroconductive film is 1 mass% or more and 20 mass% or less at a calcination temperature of TD-50 DEG C or less.

Description

Conductive film manufacturing method and conductive film

The present invention relates to a method of producing a conductive film. More specifically, the present invention relates to a method for producing a conductive film using a composition for forming a conductive film containing copper oxide particles, copper particles, and a polyol.

A method of forming a metal film on a resin substrate is known in which a dispersion of metal oxide particles is applied onto a resin substrate by a printing method, followed by heat treatment to be sintered, thereby forming a metal film or a circuit substrate. The electrical conduction point of the wiring. With the existing use of high heat. Compared with the wiring process of vacuum process (sputtering) or plating treatment, this method is simple. Energy saving. Saving resources, so it is expected in the next generation of electronics development.

For example, Patent Document 1 discloses a method for producing a metal thin film, which comprises applying a metal oxide dispersion onto a substrate and then performing heat treatment, the metal oxide dispersion comprising a particle diameter of less than 200 nm. a metal oxide and a dispersion medium containing a polyol and/or a polyether compound. Further, copper oxide is described as a metal oxide, and diethylene glycol is described as a polyhydric alcohol.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] 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 calcination treatment, not only the energy saving but also the versatility of the resin substrate is required, and the calcination treatment at a low temperature is also required. However, copper oxide and copper oxide can be used at a calcination temperature of 200 ° C or less using polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) as a resin substrate. Since the reduction of the oxide film on the copper surface is insufficient, it is difficult to obtain a conductive film having excellent conductivity and adhesion while suppressing warpage of the resin substrate.

The inventors of the present invention studied the method for producing a conductive film disclosed in Patent Document 1, and the conductivity of the obtained conductive film reached the level required recently, but the adhesion of the conductive film did not reach the required level, and the resin could not be suppressed. Warpage of the substrate.

Therefore, the present invention has been made in view of the above circumstances, and an object of the invention is to provide a method for producing a conductive film which can form a conductive film which does not cause warpage, adhesion, and conductivity of a resin substrate.

Moreover, an object of the present invention is to provide a conductive film produced by the method for producing a conductive film.

The present inventors have conducted active research on the problems of the prior art, and as a result, found that the mass ratio of copper particles to copper oxide particles in the composition for forming a conductive film and the calcination temperature and conductivity in the production step of the conductive film are controlled. The amount of organic residue in the film can solve the above problem.

That is, it was found that the object can be attained by the following constitution.

(1) A method for producing a conductive film, comprising: a coating film forming step of applying a conductive film to a resin substrate having a thermal decomposition temperature T _D to form a coating film, the conductive film containing copper oxide particles, copper particles And the ratio 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) of the polyol and the polyol is 1.0 or more and 8.0 or less, and does not contain heat or light. In the conductive film forming step, the coating film is calcined so that the amount of the organic residue in the conductive film is 1% by mass or more and 20% by mass or less at a calcination temperature of T _D -50 ° C or lower. A conductive film containing metallic copper is formed.

(2) The method for producing a conductive film according to (1), wherein the calcination temperature is 220 ° C or lower.

(3) The method for producing a conductive film according to (1) or (2), wherein the calcination temperature is 200 ° C or lower.

The method for producing a conductive film according to any one of the above aspects, wherein the amount of the organic residue is 5% by mass or more and 10% by mass or less.

(5) The method for producing a conductive film according to any one of (1) to (4), wherein a ratio of a total mass of the copper particles to a total mass of the copper oxide particles (copper particles) The total mass / total mass of the copper oxide particles is 2.0 or more and 6.0 or less.

(6) The method for producing a conductive film according to any one of (1) to (5), wherein a ratio of a total mass of the polyol to a total mass of the copper oxide particles (total mass of the polyol/oxidation) The total mass of the copper particles is 1.0 or more and 4.0 or less.

(7) The method for producing a conductive film according to any one of (1) to (6) wherein the resin substrate is a polyethylene terephthalate (PET) substrate or polyethylene naphthalate. (PEN) substrate.

The method for producing a conductive film according to any one of (1) to (7) wherein the polyol is ascorbic acid or dihydroxyacetone.

The method for producing a conductive film according to any one of (1) to (8), wherein the copper oxide particles have an average particle diameter of 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 the copper particles have an average particle diameter of 0.1 μm or more and 10 μm or less.

The method for producing a conductive film according to any one of (1) to (10), wherein the calcination treatment is carried out 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).

According to the present invention, it is possible to provide a method for producing a conductive film which can form a conductive film which does not cause warpage, adhesion, and conductivity of a resin substrate.

Moreover, according to the present invention, a conductive film produced by the method for producing the conductive film can also be provided.

Hereinafter, preferred embodiments of the method for producing a conductive film and the composition for forming a conductive film of the present invention will be described in detail.

First, the feature points of the present invention which are compared with the prior art will be described in detail.

One of the features of the present invention is that, for a coating film formed on a resin substrate having a thermal decomposition temperature T _D , the amount of organic residue in the conductive film is 1% by mass at a calcination temperature of T _D -50 ° C or lower. The calcination treatment is carried out in the above manner and at least 20% by mass. By performing the calcination treatment under these conditions, it is possible to form a conductive film having excellent adhesion and conductivity on the resin substrate without causing warpage of the resin substrate.

Further, another feature of the present invention is that the composition for forming a conductive film has a ratio of a total mass of copper particles to a total mass of copper oxide particles (total mass of copper particles/total mass of copper oxide particles) of 1.0. The above and below 8.0 include copper oxide particles and copper particles. By containing copper oxide particles and copper particles under such conditions, it is possible to form a conductive film having excellent adhesion and conductivity on the resin substrate without causing warpage of the resin substrate.

In the following, various components (such as copper oxide particles, copper particles, and polyhydric alcohol) of the conductive film-forming composition will be described in detail. Hereinafter, a method for producing a conductive film will be described in detail.

Further, in the present invention, when a certain numerical range is referred to as "X or more and Y or less" or "X~Y", 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 calcination treatment, and together with the copper particles described later, the metallic copper in the conductive film is formed.

The average particle diameter of the copper oxide particles is not particularly limited, but is preferably in the range of 10 nm or more and 100 nm or less, more preferably in the range of 20 nm or more and 50 nm or less.

When the average particle diameter of the copper oxide particles is 10 nm or more, the activity on the surface of the particles does not become excessively high, and the dispersion in the composition is easy, and the workability and storage stability are excellent. In addition, when the average particle diameter of the copper oxide particles is 100 nm or less, it is easy to use the composition as an ink composition for inkjet, and to form a pattern such as wiring by a printing method, and when the composition is conductorized, Since the active surface is enlarged, it is easily reduced to metallic copper, and the conductivity of the obtained conductive film is further improved. When the average particle diameter of the copper oxide particles is in the range of 20 nm or more and 50 nm or less, the conductivity of the obtained conductive film is further excellent.

The "copper oxide" in the present invention is a compound which does not substantially contain unoxidized copper, and specifically refers to a peak derived from copper oxide in crystal analysis by X-ray diffraction. And no compound derived from the peak of the metal was detected. The term "containing substantially no copper" means that the content of copper is 1% by mass or less based on the total mass of the copper oxide particles.

Further, copper oxide is preferably copper oxide (I) or copper (II) oxide, which is inexpensively obtained and excellent in stability in air, and further preferably oxidized. Copper (II).

As the copper oxide particles, known copper oxide particles used for the composition for forming a conductive film can be used. For example, as the copper oxide particles, NanoTek ^(R) CuO, NanoTek ^(R) Slurry CuO manufactured by CICASEI Co., Ltd., NO-0004-HP manufactured by Iolitec Co., Ltd., NO-0031 can be used. - HP, copper (II) nano powder (nanopowder) manufactured by Sigma-Aldrich Co., Ltd., and the like.

Furthermore, the average particle diameter of the copper oxide particles in the present invention means an average primary particle diameter. The average particle diameter is measured by a transmission electron microscope (TEM) or a scanning electron microscope (SEM), and the particle diameter (diameter) of at least 50 or more copper oxide particles is measured. These particle diameters were obtained by arithmetic mean. In the observation chart, when the shape of the copper oxide particles is not a perfect circular shape, the long diameter is measured as the diameter.

<copper particles>

Copper particles are contained in the composition for forming a conductive film. The copper particles and the metal copper formed by the reduction of the copper oxide of the copper oxide particles by the calcination treatment at the time of film formation constitute the metal copper in the conductive film.

The average particle diameter of the copper particles is not particularly limited, but is preferably in the range of 0.1 μm or more and 20 μm or less, and more preferably in the range of 0.1 μm or more and 10 μm or less.

When the average particle diameter of the copper particles is 0.1 μm or more, the conductive film obtained is more excellent in conductivity. Further, when the average particle diameter of the copper particles is 20 μm or less, it becomes easy Fine wiring is formed. When the average particle diameter of the copper particles is in the range of 0.1 μm or more and 10 μm or less, the adhesion and conductivity of the conductive film are further improved, which is more preferable.

As the copper particles, known metal copper particles used for the composition for forming a conductive film can be used. For example, as the copper particles, flake copper powder 1050YP, 1100YP, 1200YP, 1400YP, MA-C08JF, MA-C025KFD, MA-C05KFD, particulate atomized copper powder MA-C015K, MA-C02K manufactured by Mitsui Mining and Metals Co., Ltd. can be used. , MA-C03K, MA-C04K, MA-C08J, MA-CJU, wet copper powder 1030Y, 1050Y, 1100Y, 1200N, 1400Y, 1400YM, 1110, and the like.

Furthermore, the average particle diameter of the copper particles in the present invention means an average primary particle diameter. The average particle diameter is measured by a transmission electron microscope (TEM) observation or a scanning electron microscope (SEM), and the particle diameter (diameter) of at least 50 or more copper particles is measured, and the particle diameters are arithmetically averaged. Out. In the observation chart, when the shape of the copper particles is not a perfect circular shape, the long diameter is measured as the diameter.

<polyol>

A polyol is contained in the composition for forming a conductive film. Since the polyol has reducibility, the copper oxide in the conductive film is reduced at the time of the calcination treatment to be converted into metallic copper.

The polyhydric alcohol is not particularly limited as long as it has a compound having two or more hydroxyl groups in one molecule, and examples thereof include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, and 1,2- Butylene glycol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2,3-butanediol, pentanediol, hexanediol, xinji Alcohol, 1,1,1-trishydroxymethylethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 1,2,6-hexanetriol, 1,2,3-hexa Alcohol, 1,2,4-butanetriol, ascorbic acid, isoascorbic acid, sugar alcohols, monosaccharides, disaccharides, trisaccharides, and the like.

Examples of the sugar alcohols include: glycerols containing glycerin; butanols such as erythritol and threitol; and pentitols such as arabitol, xylitol, and adonitol; Hexitols such as durum alcohol, dulcitol, sorbitol, and mannitol; heptitols such as volemitol and sorbitol; and the like.

Examples of the monosaccharide include glyceraldehyde, threose, erythroglucose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, and idose. Aldose, galactose and other aldoses; dihydroxyacetone, erythrokholose, xylulose, ribulose, psicose, fructose, sorbose, tagatose, sedoheptulose, marshmallow, etc. Ketosaccharides and the like.

Examples of the disaccharide include sucrose, trehalose, iso-trehalose (β, β-trehalose), new trehalose (α, β-trehalose), and non-reducing sugar such as galactose; lactulose, lactose, and Maltose, cellobiose, bismuth saccharide, nigerose, isomaltose, bismuth saccharide, kelp disaccharide, gentiobiose, pine disaccharide, maltulose, palatinose Palatinose), gentibiulose, mannobiose, melibiose, melibiulose, new lactose, squill disaccharide, sucrose, rutinulose, pod Bean disaccharide, xylobiose, primrose and other reducing sugars.

Examples of the trisaccharide include Aspergillus niger trisaccharide, maltotriose, melezitose, maltotrione, raffinose, and canetriose.

Further, the polyol also includes the mirror image isomer in the presence of a mirror image isomer. For example, ascorbic acid contains L-ascorbic acid and D-ascorbic acid, and glucose contains D-glucose, L-glucose, and the like. Also, the polyol is present in the tautomer In the case of (tautomer), the tautomer is also included. For example, glucose includes α-glucopyranose, β-glucopyranose, α-glucofuranose, β-glucofuranose, and the like.

<Solvents and other ingredients>

In addition to the copper oxide particles, the copper particles, and the polyol, the conductive film-forming composition may contain a solvent (dispersion medium) or various additives (a leveling agent, a coupling agent, and a viscosity adjuster) in a range that does not impair the effects of the present invention. Other ingredients such as antioxidants, adhesives, etc.). In particular, in order to obtain a composition having moderate fluidity, it is preferred to contain a solvent.

The solvent is, for example, one selected from the group consisting of water, alcohols, ethers, esters, hydrocarbons, and aromatic hydrocarbons, or a mixture of two or more kinds having compatibility.

In terms of excellent compatibility with a polyol, the solvent can preferably be water, a water-soluble alcohol (monohydric alcohol only), an alkyl ether derived from a water-soluble alcohol (only one hydroxyl group per molecule) The following are the alkyl esters derived from a water-soluble alcohol (only one or less hydroxyl groups in one molecule), or a mixture of these solvents.

As the water, it is preferred to have a purity of at least ion-exchanged water.

As the water-soluble alcohol (monool alone), specifically, methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, cyclohexanol, 1-heptanol can be exemplified , 1-octanol, 1-nonanol, 1-nonanol, glycidol, methylcyclohexanol, 2-methyl-1-butanol, 3-methyl-2-butanol, 4-methyl- 2-pentanol, isopropanol, 2-ethylbutanol, 2-ethylhexanol, 2-octanol, terpineol, dihydroterpineol, 2-methoxyethanol, 2-ethoxyl Ethanol, 2-n-butoxyethanol, carbitol, ethyl carbitol, n-butyl carbitol, diacetone alcohol, and the like.

Among these, at least one selected from the group consisting of methanol, 2-methoxyethanol, and isopropyl alcohol is preferred because the boiling point is not excessively high and is not easily retained after the formation of the conductive film.

The alkyl ether derived from a water-soluble alcohol (only one or less hydroxyl groups in one molecule) is specifically: diethyl ether, diisobutyl ether, dibutyl ether, methyl-tert-butyl group Ether, methylcyclohexyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tetrahydrofuran, tetrahydropyran, 1,4-two Oxane and the like.

Among these, at least one selected from the group consisting of diethyl ether, diethylene glycol dimethyl ether and tetrahydrofuran is preferred because the boiling point is not excessively high and is not easily retained after the formation of the conductive film.

Specific examples of the alkyl ester derived from a water-soluble alcohol (only one or less hydroxyl groups per molecule) may be exemplified by methyl formate, ethyl formate, butyl formate, methyl acetate, and ethyl acetate. , butyl acetate, methyl propionate, ethyl propionate, butyl propionate, γ-butyrolactone and the like.

Among these, at least one selected from the group consisting of methyl formate, ethyl formate, and methyl acetate is preferred because the boiling point is not excessively high and is not easily retained after the formation of the conductive film.

Among the solvents, it is preferred to use water or a water-soluble alcohol (monool alone) as a main solvent in terms of not excessively high boiling point. The main solvent is a solvent having the highest content in a solvent.

[Method for Producing Composition for Conductive Film Formation]

The conductive film-forming composition of the present invention contains copper oxide particles, copper particles, a polyol, and a desired solvent and other components, but does not contain an organic compound which is cured by heat or light.

The organic compound which is hardened by heat or light means an organic compound which is cured by heating or an organic compound which is cured by light irradiation. Light irradiation includes electromagnetic wave irradiation.

As an organic compound hardened by heating, a thermosetting resin is mentioned, for example. Specific examples of the thermosetting resin include a phenol resin, an epoxy resin, a melamine resin, a urea resin, an unsaturated polyester resin, an alkyd resin, a polyurethane, and a thermosetting property. Polyimine and the like.

As an organic compound hardened by light irradiation, a photocurable resin is mentioned, for example. The photocurable resin is a resin which polymerizes a monomer or an oligomer by activation of a photopolymerization initiator.

In addition, the term "excluding" means that the ratio of the organic compound which is cured by heat or light is 1% by mass or less, preferably 0% by mass, based on the total of the copper oxide particles, the copper particles, and the polyol.

The content of the copper particles in the conductive film-forming composition is a value (the total mass of the copper particles/the total mass of the copper oxide particles) of the total mass of the copper particles to the total mass of the copper oxide particles is 1.0 or more and 8.0 or less. Preferably, it is an amount of 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 conductive film obtained is excellent in conductivity and the fluidity of the composition for forming a conductive film is improved. Therefore, the composition for forming a conductive film is excellent in printability. When the ratio 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 warpage of the resin substrate cannot be suppressed during the baking treatment, and the adhesion and conductivity of the conductive film produced when the temperature exceeds 8.0 are not Reach the required level.

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

When the solvent is contained in the conductive film-forming composition, the content thereof is not particularly limited, and the composition for forming a conductive film is suppressed from the viewpoint of suppressing the increase in the viscosity of the conductive film-forming composition and the operability. The total mass is preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less.

The viscosity of the composition for forming a conductive film is preferably adjusted to a viscosity suitable for printing applications such as inkjet or screen printing. In the case of performing inkjet ejection, it is preferably 1 cP to 50 cP, more preferably 1 cP to 40 cP. In the case of screen printing, it is preferably from 1000 cP to 100,000 cP, more preferably from 10,000 cP to 80,000 cP.

The method for preparing the conductive film-forming composition is not particularly limited, and a known method can be employed. For example, after adding copper oxide particles, copper particles, a polyhydric alcohol, and a solvent and other components to a solvent, an ultrasonic method (for example, treatment using an ultrasonic homogenizer), a mixer method, and a three-roll method are used. A known method such as a ball mill method disperses the components, whereby a composition can be obtained.

[Method of Manufacturing Conductive Film]

The method for producing a conductive film of the present invention includes at least a coating film forming step and a conductive film forming step. Hereinafter, each step will be described in detail.

<Coating film forming step>

The coating film forming step is a step of forming the conductive film forming composition onto the resin substrate to form a coating film. The coating film before the calcination treatment was obtained by this step. The coating film may be dried before the conductive film forming step described later.

As the resin substrate used in this step, a known resin substrate can be used. Examples of the resin substrate include a low-density polyethylene resin substrate, a high-density polyethylene resin substrate, an Aacrylonitrile Butadiene Styrene (ABS) resin substrate, and an acrylic resin base. Material, styrene resin substrate, vinyl chloride resin substrate, polyester resin substrate (polyethylene terephthalate (PET) substrate, polyethylene naphthalate (PEN) Substrate), polyacetal resin substrate, polyfluorene resin substrate, polyether phthalimide resin substrate (polyimine resin substrate), polyether ketone resin substrate, cellulose derivative substrate, paper - phenol resin substrate (paper phenol resin substrate), paper-epoxy substrate (paper epoxy substrate), paper-polyester resin substrate (paper polyester resin substrate), glass cloth - epoxy Resin substrate (glass epoxy substrate), glass cloth-polyimine resin substrate (glass polyimide substrate), glass cloth-fluororesin substrate (glass fluororesin substrate), etc. . Among these substrates, a polyethylene terephthalate (PET) substrate or a polyethylene naphthalate (PEN) substrate, more preferably polyethylene terephthalate (PET), is preferred. Substrate.

Further, the thermal decomposition temperature T _D of the resin substrate is 10% decomposition temperature (° C.), specifically, a thermogravimetry/differential thermal analyzer (TG/DTA) is used in a nitrogen atmosphere. The temperature at which the weight loss was 10% (10% weight reduction temperature) (° C.) when the thermogravimetry was measured. In general, even if it is the same kind of resin, the thermal decomposition operation may be different due to molecular weight, molecular weight distribution, branching degree, crosslinking density, etc., and thus T _{D may be} different from each other.

The method of imparting the composition for forming a conductive film to the resin substrate is not particularly limited, and a known method can be employed. For example, a coating method such as a screen printing method, a dip coating method, a spray coating method, a spin coating method, or an inkjet method can be mentioned.

The shape of the coating is not particularly limited, and may be a planar shape covering the entire surface of the resin substrate, or may be a pattern (for example, a wiring shape or a dot shape).

The coating amount of the conductive film-forming composition on the resin substrate may be appropriately adjusted depending on the film thickness of the conductive film to be used. Usually, the film thickness (thickness) of the coating film is preferably 0.01 μm to 1000 μm, more preferably It is 0.1 μm to 100 μm, more preferably 0.1 μm to 50 μm, still more preferably 1 μm to 30 μm.

<drying step>

This step is a step of drying the formed coating film to remove the solvent. This step can be carried out in accordance with the step of forming the conductive film after the coating film forming step and before the conductive film forming step.

By removing the residual solvent, in the conductive film forming step, it is possible to suppress the occurrence of minute cracks or voids caused by vaporization expansion of the solvent, and the conductivity of the conductive film and the adhesion between the conductive film and the resin substrate. In terms of aspects, it is better.

The drying treatment method may be, for example, drying by heating using a warm air dryer or the like, and drying treatment is preferably performed at a temperature lower than a calcination temperature to be described later. Specifically, the drying temperature is preferably 40 ° C or more and less than 200 ° C, more preferably 50 ° C or more and less than 150 ° C.

In the present invention, the drying treatment can be carried out in an inert gas atmosphere or in an atmosphere, preferably in an inert gas atmosphere.

<Conductive film forming step>

The conductive film forming step is a step of forming a film by a coating film at a calcination temperature of T _D -50 ° C or lower by calcining the amount of the organic residue in the conductive film to be 1% by mass or more and 20% by mass or less. The step of forming a conductive film on the coating film formed on the resin substrate. Here, T _D is the thermal decomposition temperature of the resin substrate.

The heating means for calcination is not particularly limited, and a known heating means such as an oven or a hot plate can be used. In the present invention, since the conductive film is formed by performing the calcination treatment at a relatively low temperature, there is an advantage that the process cost is low.

By performing the calcination treatment, the polyol acts as a reducing agent, and the copper oxide is reduced to be converted into metallic copper. More specifically, the metal copper particles produced by reducing the copper oxide particles in the coating film by the calcination treatment promote the subsequent adhesion of the copper particles. Melting to form particles, and then the particles are next to each other. Melting to form a copper film.

Calcination process temperature (calcining temperature) or less as long as T _D -50 ℃, is not particularly limited, as long as no more than T _D -50 ℃, is preferably higher than 220 deg.] C, more preferably higher than 200 ℃. Further, the lower limit of the calcination temperature may be as long as a conductive film for forming the composition of the copper oxide reduction temperature is converted into metallic copper, and is T _D -50 ℃ or less, is not particularly limited, as long as no more than T _D - 50 ° C, preferably 150 ° C or more, more preferably 180 ° C or more.

The time (calcination time) of the calcination treatment is not particularly limited as long as the amount of the organic residue in the conductive film is 1% by mass or more and 20% by mass or less, and is preferably 5% by mass or more and 10% by mass or less. time. In addition, the "organic residue amount" is the amount of organic matter (unit: mass %) remaining in the conductive film after the calcination treatment, and can be calcined in a nitrogen atmosphere by a differential thermal and thermal weight simultaneous measurement device (TG/DTA). The subsequent conductive film was heated to 500 ° C, and was calculated from the amount of weight loss of the organic substance amount measured thereby.

In the present invention, the calcination treatment can be carried out in an inert gas atmosphere or in an atmosphere, preferably in an inert gas atmosphere.

[conductive film]

By carrying out the above steps, a conductive film (metal copper film) containing metallic copper is obtained.

The film thickness (thickness) of the conductive film is not particularly limited, and is appropriately adjusted to an optimum film thickness depending on the intended use. In particular, the use of the printed wiring board is preferably 0.01 μm to 1000 μm, more preferably 0.1 μm to 100 μm, still more preferably 0.1 μm to 50 μm, still more preferably 1 μm to 30 μm.

In addition, the film thickness is a value (average value) obtained by measuring the thickness of any point of the conductive film at three or more places and arithmetically averaging the values.

The volume resistivity of the conductive film can be calculated by measuring the surface resistivity of the conductive film by a four-probe method and multiplying the obtained surface resistivity by the film thickness.

The conductive film may be provided on the entire surface of the resin substrate or in a pattern. The patterned conductive film is useful as a conductor wiring (wiring) such as a printed wiring board.

The method of obtaining the patterned conductive film is a method in which the conductive film forming composition is applied to the resin substrate in a pattern, and the heat treatment is performed; or the entire surface of the resin substrate is provided. A method in which a conductive film is etched into a pattern or the like.

The method of etching is not particularly limited, and a known subtractive method, semi-additive method, or the like can be employed.

When the patterned conductive film is formed as a multilayer wiring substrate, an insulating layer (insulating resin layer, interlayer insulating film, solder resist layer) may be further laminated on the surface of the patterned conductive film to form further wiring on the surface. (metal pattern).

The material of the insulating film is not particularly limited, and examples thereof include an epoxy resin, a glass epoxy resin, a polyarylamine resin, a crystalline polyolefin resin, an amorphous polyolefin resin, and a fluorine-containing resin (polytetrafluoroethylene, Perfluoroiminoimine, perfluorinated amorphous resin, etc.), polyimide resin, polyether oxime resin, polyphenylene sulfide resin, polyetheretherketone 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 preferably an epoxy resin, a polyimide resin, or a liquid crystal resin, and more preferably an epoxy resin. Specifically, ABF GX-13 manufactured by Ajinomoto Fine-Techno Co., Ltd., and the like can be mentioned.

In addition, the solder resist which is one of the materials for the insulating layer for the wiring protection is described in, for example, Japanese Laid-Open Patent Publication No. Hei 10-204150, or Japanese Patent Laid-Open No. 2003-222993, and the like. The materials described therein are used in the present invention. A commercially available product can be used as the solder resist, specifically, for example, For example, PFR800, PSR4000 (trade name) manufactured by Taiyo Ink Co., Ltd., and SR7200G manufactured by Hitachi Chemical Co., Ltd., and the like are listed.

The resin substrate (resin substrate with a conductive film) having the obtained conductive film can be used for various purposes. For example, a flexible printed circuit board, a rigid flexible printed circuit board, a rigid printed circuit board, a thin film transistor (TFT), and a radio frequency identification system (RFID) can be mentioned.

[Examples]

Hereinafter, the present invention will be further described in detail by way of examples, but the invention is not limited thereto.

[Example 1] <Preparation of a composition for forming a conductive film>

Copper oxide particles 1 (average particle diameter: 40 nm; manufactured by CI Chemical Co., Ltd., NanoTek ^(R) CuO) (100 parts by mass), copper particles 1 (average particle diameter: 3 μm; manufactured by Mitsui Mining & Mining Co., Ltd., sheet-like copper powder 1200 YP) were added. 250 parts by mass), ascorbic acid (300 parts by mass), and water (ultra-pure water) (500 parts by mass) were treated by a self-rotating revolution mixer (manufactured by THINKY Co., Ltd., defoaming Ryotaro ARE-310) for 5 minutes. Thereby, a composition for forming a conductive film is obtained.

<Production of Conductive Film>

The obtained conductive film-forming composition was applied in a stripe shape (L/S = 1 mm/1 mm) on a PET substrate (T _D = 320 ° C; manufactured by Fujifilm Business Supply Co., Ltd., FUJIX OHP FILM). Then, it was dried at 100 ° C for 10 minutes to obtain a coating film in which a composition layer for forming a conductive film was printed. Then, using an RTA sintering apparatus (Accom Thermo), heated to 180 ° C, the amount of organic residue in the conductive film was kept at 5% by mass, and then cooled to 1040 ° C and the sample was taken out. Thereby, a conductive film was obtained.

Here, the amount of the organic residue is obtained by heating the conductive film after the calcination treatment to 500 ° C in a nitrogen atmosphere by a differential thermal and thermal weight simultaneous measurement device (TG/DTA), and calculating the weight reduction amount based on the measured organic matter amount. .

<Evaluation of warpage of resin substrate>

With respect to the obtained resin substrate with a conductive film (hereinafter referred to as "sample" in the evaluation item), the plate and the sample were measured in units of 0.1 mm by the method described in 5.22 of JIS C 6481:1996. The spacing between the edges. The evaluation criteria are as follows. Furthermore, in practice, it is preferable to use an A evaluation or a B evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

A: The interval between the flat plate and the side of the sample is 0.5 mm or less.

B: The interval between the flat plate and the side of the sample exceeds 0.5 mm and is 1.0 mm or less.

C: The interval between the flat plate and the side of the sample exceeds 1.0 mm and is 2.0 mm or less.

D: The interval between the flat plate and the side of the sample exceeds 2.0 mm and is 5.0 mm or less.

E: The distance between the flat plate and the side of the sample exceeds 5.0 mm.

<Evaluation of Adhesion of Conductive Film>

A cellophane tape (24 mm in width, manufactured by Nichiban Co., Ltd.) was adhered to the obtained conductive film and peeled off. The appearance of the peeled conductive film was visually observed, and the adhesion was evaluated. The evaluation criteria are as follows. Furthermore, in practice, it is preferable to use an A evaluation or a B evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

A: No conductive film was observed on the tape, and peeling at the interface between the conductive film and the resin substrate was not observed.

B: A conductive film was slightly adhered to the tape, but peeling at the interface between the conductive film and the resin substrate was not observed.

C: A conductive film was clearly observed on the tape, and the area of peeling at the interface between the conductive film and the resin substrate was observed to be less than 5%.

D: A conductive film was clearly observed on the tape, and the area of peeling at the interface between the conductive film and the resin substrate was observed to be 5% or more and less than 50%.

E: A conductive film was clearly observed on the tape, and the area of peeling at the interface between the conductive film and the resin substrate was observed to be 50% or more.

<Evaluation of Conductivity of Conductive Film>

With respect to the obtained conductive film, the volume resistivity was measured using a four-probe method resistivity meter, and the conductivity was evaluated. The evaluation criteria are as follows. Furthermore, in practice, it is preferable to use an A evaluation or a B evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

A: The volume resistivity is less than 50μΩ. Cm.

B: The volume resistivity is 50 μΩ. Above cm and less than 100μΩ. Cm.

C: The volume resistivity is 100 μΩ. Above cm and less than 1000μΩ. Cm.

D: The volume resistivity is 1000 μΩ. More than cm.

[Example 2, Example 3]

A conductive film was produced in the same manner as in Example 1 except that the firing temperature was changed to the temperature shown in Table 1, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Example 4]

A conductive film was produced in the same manner as in Example 1 except that a PEN substrate (manufactured by Teijin DuPont Films Co., Ltd., Teonex, T _D = 410 ° C) was used instead of the PET substrate, and the resin substrate was prepared. The warpage, the adhesion of the conductive film, and the conductivity were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Example 5, Example 6]

A conductive film was produced in the same manner as in Example 1 except that the amount of the organic residue was changed to the amount shown in Table 1, and warpage of the resin substrate, adhesion of the conductive film, and conductivity were performed. Sexual evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

[Embodiment 7]

Copper oxide particles 2 (average particle diameter: 80 nm; manufactured by Eoltek Co., Ltd., NO-0031-HP) (100 parts by mass) were used instead of the copper oxide particles 1 (100 parts by mass), and Example 1 was used. A conductive film was produced in the same manner, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Embodiment 8, Example 9]

A conductive film was produced in the same manner as in Example 1 except that the content of the copper particles 1 was changed to the amount shown in Table 1, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were performed. Evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

[Embodiment 10]

Use copper particles 2 (average particle size 17 μm; manufactured by Mitsui Mining & Mining Co., Ltd., Micro A conductive film was produced in the same manner as in Example 1 except for the copper particle 1 (250 parts by mass), and the warpage of the resin substrate and the adhesion of the conductive film were observed. And conductivity was evaluated. The results of the evaluation are shown in the corresponding columns 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 instead of ascorbic acid (300 parts by mass), and warpage of the resin substrate, adhesion of the conductive film, and conduction were performed. Sexual evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

[Example 12, Example 13]

A conductive film was produced in the same manner as in Example 1 except that the content of the ascorbic acid was changed to the amount shown in Table 1, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Example 14, Example 15]

A conductive film was produced in the same manner as in Example 1 except that the calcination treatment was carried out in an N ₂ (nitrogen) atmosphere or in the atmosphere as shown in Table 1, and warpage of the resin substrate and adhesion of the conductive film were carried out. Evaluation of properties and conductivity. The results of the evaluation are shown in the corresponding columns of Table 1.

[Comparative Example 1]

A conductive film was produced in the same manner as in Example 1 except that the calcination temperature was changed to 290 ° C, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Comparative Example 2, Comparative Example 3]

A conductive film was produced in the same manner as in Example 1 except that the amount of the organic residue was changed to the amount shown in Table 1, and warpage of the resin substrate, adhesion of the conductive film, and conductivity were performed. Sexual evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

[Comparative Example 4]

A conductive film was obtained in the same manner as in Example 1 except that the copper oxide particles were not contained, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Comparative Example 5]

A conductive film was obtained in the same manner as in Example 1 except that the copper particles were not contained, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Comparative Example 6]

A conductive film was obtained in the same manner as in Example 1 except that the copper particles were not contained, and diethylene glycol (300 parts by mass) was used instead of ascorbic acid (300 parts by mass), and the resin substrate was warped and electrically conductive. The adhesion and conductivity of the film were evaluated. The results of the evaluation are shown in the corresponding columns of Table 1.

[Comparative Example 7 and Comparative Example 8]

A conductive film was produced in the same manner as in Example 1 except that the content of the copper particles 1 was changed to the amount shown in Table 1, and the warpage of the resin substrate, the adhesion of the conductive film, and the conductivity were performed. Evaluation. The results of the evaluation are shown in the corresponding columns of Table 1.

The resin substrate of Examples 1 to 15 was excellent in warpage, adhesion of the conductive film, and conductivity, and warpage of the resin substrate of the conductive films of Comparative Examples 1 to 8 and adhesion of the conductive film. At least one of the properties and conductivity is poor.

According to the comparison of Examples 1 to 3, it was confirmed that the warpage of the resin substrate having a low firing temperature was suppressed.

According to the comparison between the first embodiment and the sixth embodiment, in the first embodiment, the amount of the organic residue was 5% by mass or more, and the adhesion of the conductive film was more excellent than that of the example 6 of less than 5% by mass.

Further, according to the comparison between Example 1 and Example 5, it was confirmed that the conductive film was more excellent in the first embodiment than in Example 5 in which the amount of the organic residue was 10% by mass or less and more than 10% by mass.

According to the comparison between the first embodiment and the seventh embodiment, the conductivity of the conductive film of Example 1 in which the average particle diameter of the copper oxide particles was in the range of 20 nm or more and 50 nm or less was compared with Example 7 outside the range. More excellent.

According to the comparison between Example 1 and Example 8, it was confirmed that the value of the ratio of the total mass of the copper particles to the total mass of the copper oxide particles (the total mass of the copper particles / the total mass of the copper oxide particles) was 2.0 or more. 1 The warpage of the resin substrate was suppressed as compared with Example 8 of less than 2.0, and the conductivity of the conductive film was more excellent.

Further, according to the comparison between Example 1 and Example 9, it was confirmed that the ratio of the total mass of the copper particles to the total mass of the copper oxide particles (the total mass of the copper particles / the total mass of the copper oxide particles) was 6.0 or less. In Example 1, the conductivity was more excellent than that of Example 8 exceeding 6.0.

According to the comparison between the first embodiment and the tenth embodiment, it was confirmed that the first embodiment of the copper particles was in the range of 0.1 μm or more and 10 μm or less, and the adhesion of the conductive film was compared with that of the example 10 outside the range. Excellent in properties and conductivity.

According to the comparison of Example 1, Example 12 and Example 13, it was confirmed that the ratio of the total mass of the polyol to the total mass of the copper oxide particles (total mass of the polyol / total mass of the copper oxide particles) was 1.0. In the first embodiment and in the range of 4.0 or less, the conductive film is more excellent in conductivity than the example 12 and the example 13 outside the range.

According to the comparison of Example 1, Example 14 and Example 15, it was confirmed that Example 1 and Example 14 which were subjected to the calcination treatment in an inert gas atmosphere were compared with Example 15 which was subjected to calcination treatment in the atmosphere, and the conductive film was Adhesion and conductivity are more excellent.

Claims (12)

A method for producing a conductive film, comprising: a coating film forming step of applying a composition for forming a conductive film to a resin substrate having a thermal decomposition temperature T _D to form a coating film, wherein the conductive film forming composition contains oxidation The copper particles, the copper particles, and the polyol, wherein the ratio of the total mass of the copper particles to the total mass of the copper oxide particles is 1.0 or more and 8.0 or less, and does not contain an organic compound which is hardened by heat or light. In the conductive film forming step, the coating film is calcined to form a metal containing material so that the amount of the organic residue in the conductive film is 1% by mass or more and 20% by mass or less at a calcination temperature of T _D -50 ° C or lower. A conductive film of copper. The method for producing a conductive film according to claim 1, wherein the calcination temperature is 220 ° C or lower. The method for producing a conductive film according to claim 1, wherein the calcination temperature is 200 ° C or lower. The method for producing a conductive film according to the first aspect of the invention, wherein the organic residue amount is 5% by mass or more and 10% by mass or less. The method for producing a conductive film according to claim 1, wherein 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 claim 1, wherein a ratio of a total mass of the polyol 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 claim 1, wherein the resin substrate is a polyethylene terephthalate substrate or a polyethylene naphthalate substrate. The method for producing a conductive film according to claim 1, wherein the polyol is ascorbic acid or dihydroxyacetone. The method for producing a conductive film according to the first aspect of the invention, wherein the copper oxide particles have an average particle diameter of 20 nm or more and 50 nm or less. The method for producing a conductive film according to the first aspect of the invention, wherein the copper particles have an average particle diameter of 0.1 μm or more and 10 μm or less. The method for producing a conductive film according to claim 1, wherein the calcination treatment is carried out 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.