JP6944413B2 - Method of manufacturing conductive film and conductive film - Google Patents

Description

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

The wiring board is also called a printed wiring board or the like, and is a main component for fixing and wiring electronic components in the field of electronic devices. In this wiring board, a patterned metal film is formed on the board to form wiring, electrodes, terminals, and the like. In the field of electronic devices, similarly to a printed wiring board, a patterned metal film is formed on the substrate and used as wiring or the like, such as a touch panel, a liquid crystal display device, and an organic EL (Electroluminescence) element. And so on.

For example, Patent Document 1 describes copper fine particles having an average particle size of 1 to 100 nm coated with an azole compound, coarse copper particles having an average particle size of 0.3 to 20 μm, a resin, a chlorine compound, and a glycol-based solvent. A method for producing a conductive film, which comprises applying a conductive paste containing It is described (claim 9).

Japanese Unexamined Patent Publication No. 2016-13107

In recent years, there has been a demand for a method for producing a conductive film, which can form a conductive film in an oxidizing atmosphere and in which the formed conductive film has excellent conductivity.

Therefore, the present invention provides a method for producing a conductive film, which can form a conductive film in an oxidizing atmosphere, and the formed conductive film has excellent conductivity, and a conductive film. Make it an issue.

As a result of diligent studies to solve the above problems, the present inventors have made a contact step of contacting an insulating coating film containing copper particles with a halogen compound, and an oxidative coating film obtained in the contact step. According to the method for producing a conductive film including a heating step including heating at a temperature of more than 150 ° C. in an atmosphere, the conductive film can be formed in an oxidizing atmosphere, and the formed conductive film is excellent. The present invention has been completed, knowing that a method for producing a conductive film having a high conductivity and the ability to provide a conductive film can be provided.

That is, the present invention is the following [1] to [20].
[1] Heating including a contact step of bringing an insulating coating film containing copper particles into contact with a halogen compound, and heating the coating film obtained in the above contact step at a temperature of 180 ° C. or higher in an oxidizing atmosphere. A method for producing a conductive film including a process.
[2] The production method according to the above [1], wherein the heating step is a step including heating the coating film obtained in the contact step at a temperature of 250 ° C. or higher in an oxidizing atmosphere.
[3] The above-mentioned [1] or [2], wherein the heating step is a step including heating the coating film obtained in the contact step at a temperature of 300 ° C. or higher in an oxidizing atmosphere. Production method.
[4] The production method according to any one of the above [1] to [3], wherein the temperature is 500 ° C. or lower.
[5] The production method according to any one of the above [1] to [4], wherein the temperature is 350 ° C. or lower.
[6] The production method according to any one of [1] to [5] above, wherein in the heating step, the heating time at the above temperature is 5 seconds to 10 minutes.
[7] In the heating step, the coating film obtained in the contacting step is first heated at a temperature of 150 ° C. or lower, and the first heating coating film is heated at 180 ° C. or higher in an oxidizing atmosphere. The production method according to any one of the above [1] to [6], which includes a second heating for heating at the temperature of.
[8] The production method according to the above [7], wherein the temperature of the second heating is 250 ° C. or higher.
[9] The production method according to the above [7] or [8], wherein the temperature of the second heating is 300 ° C. or higher.
[10] The production method according to any one of the above [7] to [9], wherein the temperature of the second heating is 500 ° C. or lower.
[11] The production method according to any one of the above [7] to [10], wherein the temperature of the second heating is 350 ° C. or lower.
[12] The production method according to any one of the above [7] to [11], wherein the temperature of the first heating is 100 ° C. to 150 ° C.
[13] The production method according to any one of the above [7] to [12], wherein in the first heating, the heating time at the above temperature is 5 seconds to 10 minutes.
[14] The production method according to any one of the above [7] to [13], wherein in the second heating, the heating time at the above temperature is 5 seconds to 10 minutes.
[15] The production method according to any one of the above [1] to [14], wherein the oxidizing atmosphere is the atmosphere.
[16] In the contact step, when the insulating coating film and the halogen compound are brought into contact with each other, the insulating coating film and the solution containing the halogen compound are brought into contact with each other. The manufacturing method according to any one.
[17] The production method according to any one of the above [1] to [16], wherein the halogen compound is hydrogen halide.
[18] A conductive film containing copper and cuprous oxide.
The area ratio of copper obtained by elemental analysis by scanning electron microscope-energy dispersive X-ray spectroscopy of the cross section in the thickness direction of the conductive film is 70% or more, and
Regarding the contents of copper and cuprous oxide obtained by quantitative analysis by X-ray diffraction analysis of the surface of the conductive film, the content of copper is higher than the content of cuprous oxide.
Conductive.
[19] The conductive film according to the above [18], wherein the area ratio of the copper is 85% or more.
[20] The conductive film further contains cuprous halide,
Regarding the contents of cuprous oxide and cuprous halide obtained by quantitative analysis by X-ray diffraction analysis of the surface of the conductive film, the content of cuprous oxide is higher than the content of cuprous halide. The conductive film according to the above [18] or [19], which is often used.

According to the present invention, it is possible to provide a method for producing a conductive film, which can form a conductive film in an oxidizing atmosphere and the formed conductive film has excellent conductivity.

Further, according to the present invention, it is possible to provide a conductive film having excellent conductivity.

FIG. 1 is an image showing the results of elemental analysis of the cross section of the conductive film of Example 1 by scanning electron microscopy-energy dispersive X-ray spectroscopy. It is an image by a (SEM) scanning electron microscope, and an image showing the presence of (Cu, O, Cl) copper, oxygen, and chlorine.

Hereinafter, the method for producing the conductive film of the present invention and the conductive film will be described in detail.
In the present invention, the range represented by using "~" means a range including both ends described before and after "~" in the range.

[Manufacturing method of conductive film]
The method for producing a conductive film of the present invention includes a contact step and a heating step.

<Contact process>
The contact step is a step of bringing the insulating coating film containing copper particles into contact with the halogen compound.
In the contacting step, the reaction between copper and the halogen compound produces cuprous halide on the surface of some copper particles.

《Insulating coating film》
The insulating coating contains copper particles. In addition, the insulating coating may contain antioxidants and / or additives in addition to the copper particles. Copper particles, antioxidants and additives will be described later.

In the present invention, "insulation" is intended to be electrically insulating, and the volume resistance value is measured by the four-terminal method according to JIS C 2525: 1999 "Conductor resistance and volume resistance value test method for metal resistance materials". measurement of time is meant that more than 1.0 × 10 ⁴ Ω · cm.

(Copper particles)
The copper particles are not particularly limited, and conventionally known copper particles used for conductive film forming applications can be used. The copper particles may be primary particles or secondary particles. The shape of the copper particles is not particularly limited, and may be spherical or plate-shaped.

The average particle size of the copper particles is not particularly limited, and is the average particle size of the primary particles in the case of the primary particles and the average particle size of the secondary particles in the case of the secondary particles, but is preferably 25 nm. It is in the range of ~ 6000 nm, more preferably in the range of 30 nm to 1000 nm, and further preferably in the range of 50 nm to 500 nm.
The average particle size of the copper particles is the particle size at the point where the integrated% distribution curve of the particle size distribution measured by the particle size distribution measuring device intersects the 50% axis, and is the median size, 50% particle size, or D50. It is called.

The content of the copper particles in the insulating coating is not particularly limited, but is preferably 80% by mass to 100% by mass, more preferably 85% by mass, based on the total mass of the insulating coating. It is ~ 100% by mass, more preferably 90% by mass to 100% by mass, even more preferably 95% by mass to 100% by mass, and even more preferably 98% by mass to 100% by mass.

When the content of the copper particles in the insulating coating film is within this range, the content of copper that functions as a conductor in the obtained conductive film also increases, and a conductive film having more excellent conductivity can be obtained. Obtainable.

The content of the copper particles in the insulating coating film is measured as the content of copper in the insulating coating film using a fluorescent X-ray analyzer (Axios, manufactured by PANalytical) under the following measurement conditions. be able to.
Line: Kα ray Crystal: LIF200
Collimator: 150 μm
Detector: Duplex
Tube filter: None Voltage: 60kV
Current: 60mA
Measurement time: 40 seconds Irradiation area: 20φ

(Antioxidant)
((Type of antioxidant))
The type of the antioxidant is not particularly limited, but is preferably at least one selected from the group consisting of redactone.

The redactone means an organic compound having a structure represented by the following formula (I) or the following formula (II) in which a carbonyl group is bonded next to an enol structure (hereinafter referred to as “reductone structure”). .. Redacton is an organic acid with reducing and highly acidic properties.

Representative examples of the above-mentioned redactone are glucinic acid represented by the following formula (Ia), redactic acid represented by the following formula (Ib), and ascorbic acid and ascorbic acid derivatives described later, but are limited thereto. is not it.

The additive is preferably at least one selected from the group consisting of ascorbic acid, ascorbic acid derivatives and citric acid, and more preferably at least one selected from the group consisting of ascorbic acid and ascorbic acid derivatives. , More preferably ascorbic acid.

The ascorbic acid is (2R) -2-[(1S) -1,2-dihydroxyethyl] -3,4-dihydroxy-2H-furan-5-one (a compound represented by the following formula (A-1)). This compound may be referred to as "ascorbic acid in the narrow sense" or "L-ascorbic acid"), (2S) -2-[(1R) -1,2-dihydroxyethyl] -3,4-dihydroxy- 2H-furan-5-one (compound represented by the following formula (A-2); this compound may be referred to as "D-ascorbic acid"), (2S) -2-[(1S) -1. , 2-Dihydroxyethyl] -3,4-dihydroxy-2H-furan-5-one (compound represented by the following formula (A-3); this compound may be referred to as "L-isoascorbic acid". ) And (2R) -2-[(1R) -1,2-dihydroxyethyl] -2,3-dihydroxy-2H-furan-5-one (compound represented by the following formula (A-4); this compound Is sometimes referred to as "erythorbic acid" or "D-isoascorbic acid").) Is at least one compound selected from the group consisting of.

The ascorbic acid derivative is preferably represented by the compound represented by the following general formula (B-1) (sometimes referred to as "ascorbic acid derivative (B-1)") or the following general formula (B-2). It is a compound (sometimes referred to as "ascorbic acid derivative (B-1)").
The reducing power for copper oxide is due to the enol structure in the ascorbic acid derivative. Therefore, it is also possible to synthesize a derivative of ascorbic acid in a form that retains its structure, and appropriately adjust the solubility and polarity for use.

一般式（Ｂ−１）中、Ｒ^１およびＲ^２は、それぞれ独立に、水素原子または置換基を有してよいアシル基を表す。ただし、Ｒ^１およびＲ^２は同時に水素原子を表さない。 -Ascorbic acid derivative represented by the general formula (B-1)

In the general formula (B-1), R ¹ and R ² each independently represent an acyl group which may have a hydrogen atom or a substituent. However, R ¹ and R ² do not represent hydrogen atoms at the same time.

^{The acyl group in R 1} and R ² in the above general formula (B-1) is not particularly limited, but is preferably a linear, branched, monocyclic or condensed polycyclic fat having 1 to 18 carbon atoms. A carbonyl group to which a group is bonded or a carbonyl group to which a monocyclic or condensed polycyclic aryl group having 6 to 10 carbon atoms is bonded.

Specific examples of the acyl group include formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, isovaleryl group, pivaloyl group, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, cyclopentylcarbonyl group and cyclohexylcarbonyl. Any one selected from the group consisting of a group, an acryloyl group, a methacryloyl group, a crotonoyl group, an isocrotonoyl group, an oleoyl group, a benzoyl group, a 1-naphthoyl group and a 2-naphthoyl group, but is limited thereto. It's not a thing.

In each of the above acyl groups, the hydrogen atom in the acyl group may be substituted with a substituent, whereby the solubility and polarity can be further adjusted.
Specific examples of the above-mentioned substituents are, but are not limited to, one or more kinds of substituents selected from the group consisting of a hydroxyl group and a halogen atom.

ただし、上記式（Ｂ−１−Ｘ）中、Ｘは以下に示す化学構造からなる群から選択されるいずれか１つを表す。なお、各化学構造中の「＊」は、Ｘがアスコルビン酸の五員環部位に結合する位置を示す。

A typical example of the ascorbic acid derivative (B-1) is represented by the following formula (B-1-X). However, the ascorbic acid derivative (B-1) in the present invention is not limited to these representative examples.

However, in the above formula (B-1-X), X represents any one selected from the group consisting of the following chemical structures. In addition, "*" in each chemical structure indicates the position where X is bonded to the five-membered ring site of ascorbic acid.

一般式（Ｂ−２）中、Ｒ^３およびＲ^４は、それぞれ独立に、水素原子または置換基を有してよいアルキル基を表す。 ・ General formula (B-2)

In the general formula (B-2), R ³ and R ⁴ each independently represent an alkyl group which may have a hydrogen atom or a substituent.

The compound represented by the general formula (B-2) is an ascorbic acid derivative in which an acetal structure or a ketal structure is formed by reacting two hydroxyl groups existing in the side chain of ascorbic acid with an aldehyde or a ketone.

^{The alkyl groups in R 3} and R ⁴ in the above general formula (B-2) are not particularly limited, but are preferably linear, branched chain, monocyclic or condensed polycyclic alkyl groups having 1 to 18 carbon atoms. be.

Specific examples of the above alkyl groups include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, octadecyl group, isopropyl group and isobutyl group. Isopentyl group, sec-butyl group, tert-butyl group, sec-pentyl group, tert-pentyl group, tert-octyl group, neopentyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group and Any one selected from the group consisting of 4-decylcyclohexyl groups, but is not limited thereto.

In each of the above alkyl groups, the hydrogen atom in the alkyl group may be substituted with a substituent, whereby the solubility and polarity can be further adjusted.
Specific examples of the above-mentioned substituents are, but are not limited to, one or more kinds of substituents selected from the group consisting of a hydroxyl group and a halogen atom.

The R ³ and the R ⁴ may be integrated to form a ring structure.

ただし、上記式（Ｂ−２−Ｙ）中、Ｙは以下に示す化学構造からなる群から選択されるいずれか１つを表す。なお、各化学構造中の「＊」は、Ｙがアスコルビン酸の五員環部位に結合する位置を示す。 A typical example of the ascorbic acid derivative (B-2) is represented by the following formula (B-2-Y). However, the ascorbic acid derivative (B-2) in the present invention is not limited to these representative examples.

However, in the above formula (B-2-Y), Y represents any one selected from the group consisting of the following chemical structures. In addition, "*" in each chemical structure indicates the position where Y binds to the five-membered ring site of ascorbic acid.

((Content of antioxidant))
When the insulating coating contains an antioxidant, the content is not particularly limited, but is preferably 0.10% by mass to 5.0% by mass with respect to the total mass of the insulating coating. It is preferably 0.50% by mass to 5.0% by mass, more preferably 0.50% by mass to 3.0% by mass, and even more preferably 0.50% by mass to 2.0% by mass.
When the insulating coating contains an antioxidant, the reaction between the copper particles and oxygen in the contact step is suppressed, and more oxygen and unreacted copper particles remain, so that the copper particles and oxygen in the heating step remain. The number of copper particles involved in the reaction with is increased, and a conductive film having better conductivity can be produced.

(Additive)
((Type of additive))
The type of the additive is not particularly limited, but is preferably a resin or an alcohol compound having a boiling point of 250 ° C. or higher.

Examples of the resin include polyvinylpyrrolidone (abbreviation: PVP), polyvinyl butyral (abbreviation: PVB), polyvinyl alcohol (abbreviation: PVA), and cellulose ester.

The alcohol compound having a boiling point of 250 ° C. or higher is a monohydric alkyl alcohol such as 1-icosanol (boiling point 372 ° C.) or 1-tetracosanol (boiling point 395 ° C.); 1,6-hexanediol (boiling point 250 ° C.). , Divalent alkyl alcohols such as 1,7-heptanediol (boiling point 259 ° C); trialkylene glycols such as triethylene glycol (boiling point 287 ° C), tripropylene glycol (boiling point 273 ° C); glycerin (propane-1,2) , 3-Triol) (boiling point 290 ° C), trimethylolpropane (boiling point 250 ° C or higher), trimethylolethane (boiling point 250 ° C or higher) and other trihydric alkyl alcohols; erythritol (boiling point 329 ° C) and other tetravalent alkyl Alcohols; pentahydric alcohols such as pentaerythritol (boiling point 250 ° C. or higher); hexahydric alkyl alcohols such as mannitol (boiling point 290 ° C.) and the like. The boiling point is the boiling point under normal pressure (100 kPa).

((Additive content))
When the insulating coating film contains an additive, the content is not particularly limited, but is preferably 0.10% by mass to 15% by mass, more preferably 0, based on the total mass of the insulating coating film. .10% by mass to 10% by mass, more preferably 0.10% by mass to 5.0% by mass, still more preferably 0.10% by mass to 3.0% by mass, and even more preferably 0. .10% by mass to 2.0% by mass.
When the insulating coating film contains an additive, the necking of copper particles is promoted in the heating step, and a conductive film having more excellent conductivity can be produced.

<< Manufacturing method of insulating coating film >>
The insulating coating film can be produced, for example, by applying a conductive film forming composition described later to the surface of a base material.

(Composition for forming a conductive film)
The composition for forming a conductive film contains copper particles and a dispersion medium. Further, the composition for forming a conductive film may contain an antioxidant and / or an additive in addition to the copper particles and the dispersion medium. Copper particles, antioxidants and additives are as described above. The dispersion medium will be described later.

((Copper particle content))
The content of the copper particles in the composition for forming a conductive film with respect to the total mass is not particularly limited, but is preferably 80% by mass or more and less than 100% by mass, and more preferably 85% by mass or more and 100% by mass. %, More preferably 90% by mass or more and less than 100% by mass, still more preferably 95% by mass or more and less than 100% by mass, and even more preferably 98% by mass or more and less than 100% by mass.
When the content of the copper particles in the composition for forming a conductive film with respect to the total mass of the solid content is within the above range, the conductivity of the conductive film produced by the method for producing a conductive film of the present invention is better. It becomes a thing.

The content of the copper particles with respect to the total mass of the conductive film-forming composition is not particularly limited, but is preferably 40% by mass or more and less than 100% by mass, and more preferably 40% by mass to 90% by mass. Yes, more preferably 40% by mass to 50% by mass.

((Dispersion medium))
(((Type of dispersion medium)))
The dispersion medium is not particularly limited as long as it can disperse the copper particles.
Specific examples of the dispersion medium include water, methanol, ethanol, propanol, 2-propanol, cyclohexanone, cyclohexanol, terpineol, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, and ethylene glycol. It is at least one selected from the group consisting of monobutyl ether acetate, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate, and is preferably ethylene glycol.

(Base material)
As the base material, conventionally known ones can be used.
Specific examples of the material used for the base material are resin, paper, glass, silicon-based semiconductor, compound semiconductor, metal, metal oxide, metal nitride, wood, or a composite thereof. It is not limited to.

Specific examples of the above resins include low-density polyethylene resin, high-density polyethylene resin, ABS (Acrylonitrile Butadiene Styrene) resin, acrylic resin, styrene resin, vinyl chloride resin, polyester resin (polyethylene terephthalate (PET)), polyacetal resin, and polysulfone resin. , Polyetherimide resin, polyetherketone resin, polyimide resin, and cellulose derivative, but are not limited thereto.
Specific examples of the above papers include coating printing paper, fine coating printing paper, coating printing paper (art paper, coated paper), special printing paper, copy paper (PPC paper), and unbleached wrapping paper (both for heavy bags). Sarah kraft paper, Ryosara kraft paper), bleached wrapping paper (bleached kraft paper, pure white roll paper), coated balls, chip balls, and cardboard, but are not limited to these.
Specific examples of the above glass are, but are not limited to, soda glass, borosilicate glass, silica glass, and quartz glass.
Specific examples of the silicon-based semiconductor are amorphous silicon and polysilicon, but the present invention is not limited thereto.
Specific examples of the compound semiconductor are, but are not limited to, CdS, CdTe and GaAs.
Specific examples of the above metals are, but are not limited to, copper, iron, and aluminum.
Specific examples of the above metal oxides include alumina, sapphire, zirconia, titania, ittrium oxide, indium oxide, ITO (indium tin oxide), IZO (indium zinc oxide), nesa (tin oxide), and ATO (antimony-doped oxidation). Tin), fluorine-doped tin oxide, zinc oxide, AZO (aluminum-doped zinc oxide), and gallium-doped zinc oxide, but are not limited thereto.
Specific examples of the metal nitride are, but are not limited to, aluminum nitride.
Specific examples of the above-mentioned composites include paper-resin composites such as paper-phenol resin, paper-epoxy resin, and paper-polyester resin, glass cloth-epoxy resin (glass epoxy resin), and glass cloth-polymethyl resin. And glass cloth-fluororesins, but not limited to these.
The base material forming the conductive film of the present invention is not particularly limited, but is preferably a glass base material, a polyimide base material, or a polyethylene terephthalate (PET) base material.

((Content of antioxidant))
When the conductive film forming composition contains an antioxidant, the content of the antioxidant is not particularly limited with respect to the total mass of the solid content of the conductive film forming composition, but is preferably 0.10% by mass. ~ 5.0% by mass, more preferably 0.50% by mass to 5.0% by mass, still more preferably 0.50% by mass to 3.0% by mass, still more preferably 0.50% by mass. % To 2.0% by mass.

((Additive content))
When the conductive film forming composition contains an additive, the content of the additive is not particularly limited with respect to the total mass of the solid content of the conductive film forming composition, but is preferably 0.10 mass. % To 15% by mass, more preferably 0.10% by mass to 10% by mass, still more preferably 0.10% by mass to 5.0% by mass, and even more preferably 0.10% by mass to 3%. It is 0.0% by mass, and even more preferably 0.10% by mass to 2.0% by mass.

((Method for preparing a composition for forming a conductive film))
The method for preparing the composition for forming a conductive film can be described below, for example.

The method for mixing the copper particles and the dispersion medium is not particularly limited, and a conventionally known method can be adopted.
For example, after adding copper particles to a dispersion medium, the components are dispersed by known means such as an ultrasonic method (for example, treatment with an ultrasonic homogenizer), a mixer method, a three-roll method, and a ball mill method. Allows the composition to be obtained.
When the composition for forming a conductive film contains an antioxidant and / or an additive, the antioxidant and / or the additive may be mixed with the dispersion medium, and the method is not particularly limited.

((Method of applying the composition for forming a conductive film to the surface of the substrate))
The method of applying the conductive film forming composition to the surface of the base material is not particularly limited, and conventionally known methods can be adopted.
For example, a coating method such as a screen printing method, a dip coating method, a spray coating method, a spin coating method, and 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 base material, or a pattern shape, for example, a wiring shape or a dot shape.

The amount of the composition for forming a conductive film applied to the surface of the substrate may be appropriately adjusted according to the desired film thickness of the conductive film, but usually, the thickness (film thickness) of the coating film is preferably 2 μm. It is ~ 600 μm, more preferably 10 μm to 300 μm, and even more preferably 10 μm to 200 μm.

After applying the composition for forming a conductive film to the surface of the base material, the coating film may be dried. The method for drying the coating film is not particularly limited, and a conventionally known method can be adopted.
For example, the coating film can be dried using a warm air dryer or the like.
The temperature at which the coating film is dried is not particularly limited, but is preferably 0 ° C. to 150 ° C., more preferably 0 ° C. to 120 ° C., still more preferably 0 ° C. to 100 ° C., and even more preferably. It is 15 ° C to 100 ° C.
The atmosphere when the coating film is dried is not particularly limited, and may be either an oxidizing atmosphere or a non-oxidizing atmosphere.
The oxidative atmosphere is preferably in a mixed gas of oxygen and an inert gas containing 0.5% by volume or more of oxygen. Here, examples of the inert gas include nitrogen, argon and xenon. A particularly preferred oxidative atmosphere is in the air or in the atmosphere.
The non-oxidizing atmosphere is preferably in hydrogen gas, carbon dioxide gas, nitrogen gas, or noble gas such as helium, neon, argon, krypton or xenon.

<< Method of contacting an insulating coating film with a halogen compound >>
The method of contacting the insulating coating with the halogen compound is not particularly limited, and for example, a method of immersing in a liquid containing a halogen compound (dip coat), a method of applying a liquid containing a halogen compound, and a gas containing a halogen compound. There is a method of spraying.

The number of contacts between the insulating coating film and the halogen compound is not limited to one, and may be two or three or more times. By contacting the insulating coating film with the halogen compound multiple times, the reaction between the copper particles in the insulating coating film and the halogen compound is promoted, and the finally obtained conductive film has more excellent conductivity. Become.

(Halogen compound)
The halogen compound is not particularly limited as long as it is a compound containing halogen.
Examples thereof include ionic compounds containing halogenated ions, inorganic compounds containing halogens via covalent bonds, and organic compounds containing halogens via covalent bonds.

In the present invention, halogen refers to fluorine (element symbol: F), chlorine (element symbol: Cl), and bromine (element symbol) among the Group 17 elements in the IUPAC (International Union of Pure and Applied Chemistry) periodic table. : Br) and iodine (elemental symbol: I), preferably chlorine and bromine. Further, in the present invention, astatine (element symbol: At) and tennessine (element symbol: Ts) are not included in the halogen.

((Ionic compounds containing halide ions))
The ionic compound containing the halide ion is at least one selected from the group consisting of, for example, a halide of an alkali metal, a halide of an alkaline earth metal, a hydrogen halide of amine and ammonium halide. It is preferably at least one selected from the group consisting of alkali metal halides and alkaline earth metal halides, and more preferably alkali metal halides.

Specific examples of the alkali metal halide include chlorides such as lithium chloride, sodium chloride and potassium chloride, bromides such as lithium bromide, sodium bromide and potassium bromide, and lithium iodide, sodium iodide and iodide. Iodide such as potassium.
The alkali metal halide is preferably alkali metal chloride or bromide, more preferably sodium or potassium chloride or bromide, and even more preferably sodium chloride or sodium bromide.

In the present invention, the alkali metal refers to lithium (element symbol: Li), sodium (element symbol: Na), potassium (element symbol: K), rubidium (element symbol: element symbol) among the Group 1 elements of the IPAC periodic table. : Rb) and cesium (element symbol: Cs), preferably lithium, sodium and potassium. In the present invention, francium (element symbol: Fr) is not included in the alkali metal.

Further, in the present invention, the alkaline earth metal refers to barium (element symbol: Be), magnesium (element symbol: Mg), calcium (element symbol: Ca), and strontium (element symbol: Ca) among the Group 2 elements of the IUPAC periodic table. It refers to element symbol: Sr) and barium (element symbol: Ba), preferably calcium, strontium and barium, and more preferably calcium. In the present invention, radium (element symbol: Ra) is not included in alkaline earth metals.

((Inorganic compounds containing halogens via covalent bonds))
Examples of the inorganic compound containing a halogen via a covalent bond include hydrogen halide.
Examples of hydrogen halides are hydrogen chloride, hydrogen bromide, hydrogen iodide and hydrogen fluoride.
The hydrogen halide is preferably at least one selected from the group consisting of hydrogen chloride, hydrogen bromide and hydrogen iodide, and more preferably at least one selected from the group consisting of hydrogen chloride and hydrogen bromide. One, more preferably hydrogen chloride or hydrogen bromide.

((Organic compounds containing halogens via covalent bonds))
Examples of the above-mentioned organic compounds containing halogen via a covalent bond include acetyl chloride (also known as chloride or acetyl chloride), acetyl bromide (also known as bromide acetate or acetyl chloride), and acetyl iodide (also known as iodine acetate or acetyl). Iodide), propionyl chloride (also known as propionic acid chloride or propionyl chloride), propionyl bromide (also known as propionate bromide or propionyl bromide), propionyl iodide (also known as propionic acid iodide or propionyl iodide), benzoyl chloride (also known as benzoyl chloride). : Chloride benzoate or benzoyl chloride), benzoyl bromide (also known as bromide benzoate or benzoyl bromide) and benzoyl iodide (also known as iodide benzoate or benzoyl iodide).
In the method for producing a conductive film of the present invention, when an insulating coating film is brought into contact with these carboxylic acid halides in the atmosphere, hydrogen halide is generated due to decomposition of the carboxylic acid halide, and the hydrogen halide is insulated. It is considered that it will come into contact with the sex coating.

<Heating process>
The heating step is a step including heating the coating film obtained in the contact step at a temperature of 180 ° C. or higher in an oxidizing atmosphere.

In the heating step, cuprous oxide is produced on the surface of some copper particles by the reaction of copper and oxygen. Oxidation of copper increases the volume of copper particles, and a force acts to bring the copper particles closer to each other in the coating film. This force causes the copper particles produced by the cuprous halogenated copper particles to come into contact with each other on the surface, and the copper halides fall off to neck the copper particles. It is considered that a conductor is formed by the progress of necking between copper particles in the film, and a conductive film having excellent conductivity can be obtained.

The heating temperature in the heating step is preferably 250 ° C. or higher, more preferably 300 ° C. or higher. The upper limit of the heating temperature is not particularly limited, but is preferably 500 ° C. or lower, and more preferably 350 ° C. or lower. When the heating temperature is within this range, the reaction between copper and oxygen on the surface of the copper particles proceeds, and the conductivity of the obtained conductive film becomes more excellent.

The atmosphere during heating in the heating step is not particularly limited as long as it is an oxidative atmosphere, but is preferably in a mixed gas of oxygen and an inert gas containing 0.5% by volume or more of oxygen. Here, examples of the inert gas include nitrogen, argon and xenon. A particularly preferred oxidative atmosphere is in the air or in the atmosphere.

In the heating step, the coating film obtained in the contact step is first heated at a temperature of 150 ° C. or lower, and the first heated coating film is heated at a temperature of more than 150 ° C. in an oxidizing atmosphere. It may be a step including a second heating.

《First heating》
The temperature of the first heating (sometimes abbreviated as "first heating") is not particularly limited as long as it is 150 ° C. or lower, but is preferably 0 ° C. to 150 ° C., and more preferably 100 ° C. to 150 ° C. Is. When the temperature of the first heating is within this range, the reaction between the halogen compound in contact with the coating film and the copper particles is likely to occur, and the oxidation of the copper particles does not proceed excessively. The formation of copper oxide is promoted.

The atmosphere at the time of the first heating is not particularly limited, and may be either an oxidizing atmosphere or a non-oxidizing atmosphere.
The oxidative atmosphere is preferably in a mixed gas of oxygen and an inert gas containing 0.5% by volume or more of oxygen. Here, examples of the inert gas include nitrogen gas, carbon dioxide gas, and noble gases such as helium, neon, argon, krypton, and xenon. A particularly preferred oxidative atmosphere is in the air or in the atmosphere.
The non-oxidizing atmosphere is preferably in hydrogen gas, carbon dioxide gas, nitrogen gas, or noble gas such as helium, neon, argon, krypton or xenon.

《Second heating》
The temperature of the second heating is preferably 250 ° C. or higher, more preferably 300 ° C. or higher. The upper limit of the temperature of the second heating is not particularly limited, but is preferably 500 ° C. or lower, and more preferably 350 ° C. or lower. When the temperature of the second heating is within this range, the reaction of copper and oxygen on the surface of the copper particles proceeds, and the conductivity of the obtained conductive film becomes more excellent.

The atmosphere during the second heating is not particularly limited as long as it is an oxidative atmosphere, but is preferably in a mixed gas of oxygen and an inert gas containing 0.5% by volume or more of oxygen. Here, examples of the inert gas include nitrogen gas, carbon dioxide gas, and noble gases such as helium, neon, argon, krypton, and xenon. A particularly preferred oxidative atmosphere is in the air or in the atmosphere.

[Conducting film]
The conductive film of the present invention contains copper and cuprous oxide.
Further, the conductive film of the present invention has an area ratio of copper of 70% or more obtained by elemental analysis by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) in a cross section in the thickness direction of the conductive film. Yes, preferably 80% or more, more preferably 85% or more. If the area ratio of copper in the cross section in the thickness direction of the conductive film is smaller than 70%, the conductivity of the conductive film becomes insufficient. The upper limit is not particularly limited, but is preferably 90% or less.

Further, in the conductive film of the present invention, the copper content is higher than the content of cuprous oxide with respect to the content of copper and cuprous oxide obtained by quantitative analysis of the surface of the conductive film by X-ray diffraction analysis. There are also many. If the content of copper in the conductive film is smaller than the content of cuprous oxide, the conductivity of the conductive film becomes insufficient.

More preferably, the conductive film of the present invention contains cuprous oxide with respect to the contents of cuprous oxide and cuprous halide obtained by quantitative analysis of the surface of the conductive film by X-ray diffraction analysis. Is higher than the content of cuprous halide. When the content of cuprous oxide in the conductive film is higher than the content of cuprous halide, the conductivity of the conductive film becomes more excellent. This is because when the conductive film is produced by the method for producing a conductive film of the present invention, the surface of the copper particles is oxidized by oxygen to increase the volume in the heating step, so that a force for crimping the copper particles to each other works. Necking of copper particles is promoted, but when the content of cuprous oxide is higher than the content of cuprous halide, it is considered that the force for crimping the copper particles to each other is larger.

The quantitative analysis by the above-mentioned X-ray diffraction analysis is measured using X-RAY DIFFRACTOMETER RINT-Ultima-III manufactured by Rigaku Corporation.
The peak intensity ratio is calculated by the following method.
(Measurement condition)
2Θ / ω: 30-80 degrees Sampling step: 0.01 degrees Speed: 10 degrees / minute ATT: Open DS: 1.00 mm
SS: Open RS: Open Optical system Parallel slit: PB
Incident vertical restriction solar slit: V5
Vertical restriction slit: 10 x 10
Parallel slit analyzer: PSA
(Peak intensity ratio calculation method)
Baseline Average value in the range of 10-20 degrees Copper bromide 2Θ = 27.1 degrees Copper chloride 2Θ = 28.5 degrees Copper oxide 2Θ = 36.4 degrees 0-valent copper 2Θ = 43 .3 degree bromide copper peak intensity ratio = (2Θ = 27.1 degree count intensity-baseline value) ÷ (2Θ = 27.1 degree count intensity-baseline value + 2Θ = 28.5 degree count intensity-base Line value +2Θ = 36.4 degree count strength-baseline value +2Θ = 43.3 degree count strength-baseline value) x 100
Copper chloride peak intensity ratio = (2Θ = 28.5 degree count strength-baseline value) ÷ (2Θ = 27.1 degree count strength-baseline value + 2Θ = 28.5 degree count strength-baseline value + 2Θ = 36.4 degree count intensity-baseline value + 2Θ = 43.3 degree count intensity-baseline value) x 100
Copper oxide peak intensity ratio = (2Θ = 36.4 degree count intensity-baseline value) ÷ (2Θ = 27.1 degree count intensity-baseline value + 2Θ = 28.5 degree count intensity-baseline value + 2Θ = 36 .4 degree count intensity-baseline value + 2Θ = 43.3 degree count intensity-baseline value) x 100
Zero-valent copper peak intensity ratio = 100-Copper bromide peak intensity ratio-Copper chloride peak intensity ratio-Copper oxide peak intensity ratio

For element analysis by scanning electron microscope-energy dispersion X-ray spectroscopy of the cross section of the conductive film in the thickness direction, cross-section processing of the coating film is performed using a FIB-SEM (focused ion beam-scanning electron microscope) compound machine. Is performed, and element analysis is performed by SEM-EDS (scanning electron microscope-energy dispersed X-ray spectroscopy). The area ratio of copper and the part other than copper is calculated using the image analysis software WIN-Roof (manufactured by Mitani Corporation).

[Preparation of composition for forming a conductive film]
<Composition for forming a conductive film 1>
Copper particle dispersion (manufactured by Promethean Particles; containing 49.0% by mass of copper particles having an average particle diameter of 80 nm, 1.0% by mass of an antioxidant, and 50.0% by mass of ethylene glycol; hereinafter, "copper particle dispersion 1" The composition for forming a conductive film (hereinafter, may be referred to as “composition for forming a conductive film 1”).

<Composition for forming a conductive film 2>
The copper particle dispersion 1 and polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.) are mixed in the amounts shown in Table 1 to form a conductive film forming composition (hereinafter referred to as "conductive film forming composition 2"). In some cases.) Was prepared.

<Composition for forming a conductive film 3>
Copper particle dispersion 1 and trimethylolpropane (manufactured by Wako Pure Chemical Industries, Ltd.) are mixed in the blending amounts shown in Table 1 to form a conductive film forming composition (hereinafter, "conductive film forming composition 3"). In some cases.) Was prepared.

In Table 1, "Copper particle dispersion 1" is a copper particle dispersion (manufactured by Promethean Particles; 49.0% by mass of copper particles having an average particle diameter of 80 nm, 1.0% by mass of an antioxidant, and 50.0 of ethylene glycol. (Including% by mass).

[Preparation of halogen compound solution]
Hydrochloride (hydrogen chloride concentration 36.0% by mass; manufactured by Wako Pure Chemical Industries, Ltd.) and ethanol (manufactured by Wako Pure Chemical Industries, Ltd.), or hydrobromic acid (hydrogen bromide concentration 48.0% by mass; Wako Pure Chemical Industries, Ltd.) (Manufactured by Wako Pure Chemical Industries, Ltd.) and ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed to prepare solutions A to H in which the blending amounts of hydrogen chloride, hydrogen bromide, water and ethanol were the amounts shown in Table 2.
In addition, Solution I containing only ethanol was prepared.

[Example 1]
<Manufacturing of insulating coating film>
A glass substrate (length 76 mm × width 26 mm × thickness 0.9 mm; manufactured by Matsunami Glass Co., Ltd.) was prepared.
On this glass substrate, the conductive film forming composition 1 was applied with a coil bar to a length of 61 mm, a width of 26 mm, and a wet thickness of 40 μm to form a coating film on the surface of the glass substrate.
The coating film formed on the glass substrate was dried in the air at 25 ° C. for 7 days to form an insulating coating film on the glass substrate. Table 3 shows the types of the conductive film forming composition, the types of the base material, and the copper particle content [mass%] of the insulating coating film.

<Contact with halogen compounds>
The glass substrate on which the insulating coating film was formed was immersed in the solution A prepared as described above at room temperature (25 ° C.) for 5 seconds and dip-coated. Table 3 shows the contact conditions.

<Heating after contact with halogen compounds>
After dipping the halogen compound on the glass substrate, it is heated at 150 ° C. for 1 minute (first heating) in the air, and then heated at 300 ° C. for 1 minute (second heating) in the air. rice field. Table 3 shows the heating conditions.

<Evaluation of conductivity>
The volume resistance value of the obtained film was measured by the four-terminal method. Table 3 shows the volume resistance values.

<Component analysis of conductive film>
As a result of elemental analysis by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) of the cross section of the conductive film in the thickness direction under the above-mentioned conditions, the area ratio of copper was 89.6%, and the area ratio of the voids was 89.6%. The area ratio was 10.4%.
The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Copper (0) 92.5%, cuprous chloride 5.5%, cuprous oxide 2.0%

FIG. 1 is an image obtained by elemental analysis of a cross section of the conductive film produced in Example 1 by a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS). In FIG. 1, "SEM" is an image taken by a scanning electron microscope, and "Cu", "O", and "Cl" are element mapping images of copper (0), oxygen, and chlorine, respectively.

[Examples 2 to 8]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1.
The substrate on which the insulating coating film was formed was subjected to solution B (Example 2), solution C (Example 3), solution D (Example 4), solution E (Example 5), and solution F (Example 5) in the air. Example 6), soaked in solution G (Example 7) or solution H (Example 8) for 5 seconds and dip-coated.
Then, in the same manner as in Example 1, the coating film dip-coated with any of the solutions B to H is heated in the air at 150 ° C. for 1 minute, and then in the air at 300 ° C. for 1 minute. To produce a conductive film.
The volume resistance value of the produced conductive film was measured in the same manner as in Example 1. Table 3 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Example 4: Copper (0) 70.5%, cuprous chloride 23.0%, cuprous oxide 6.5%
Example 8 ... Copper (0) 71.5%, cuprous bromide 22.1%, cuprous oxide 6.4%

[Examples 9 and 10]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1, and the formed insulating coating film was dip-coated with the solution A.
Then, the coating film dip-coated with the solution A is heated at 150 ° C. for 1 minute in the air, and then 180 ° C. (Example 9) or 250 ° C. (Example 10) in the air as shown in Table 3. ) For 1 minute to produce a conductive film.
The volume resistance value of the produced conductive film was measured in the same manner as in Example 1. Table 3 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Example 9 ... Copper (0) 92.3%, cuprous chloride 5.8%, cuprous oxide 1.9%
Example 10 ... Copper (0) 85.8%, cuprous chloride 12.5%, cuprous oxide 1.8%

[Example 11]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1, and the formed insulating coating film was dip-coated with the solution A.
Then, the coating film dip-coated with the solution A was heated in the air at 150 ° C. for 1 minute, and then in the air at 300 ° C. for 5 minutes as shown in Table 3, to produce a conductive film. ..
The volume resistance value of the produced conductive film was measured in the same manner as in Example 1. Table 3 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Example 11 ... Copper (0) 72.2%, cuprous chloride 22.5%, cuprous oxide 5.3%

[Example 12]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1, and the formed insulating coating film was dip-coated with the solution A.
Then, as shown in Table 3, the coating film dip-coated with the solution A was heated at 300 ° C. for 1 minute in the air to produce a conductive film. The heating in the air at 150 ° C. for 1 minute, which was carried out in Example 1, was not carried out in this example.
The volume resistance value of the produced conductive film was measured in the same manner as in Example 1. Table 3 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Example 12 ... Copper (0) 78.4%, cuprous chloride 11.4%, cuprous oxide 10.2%

[Examples 13 and 15]
Insulation in the same manner as in Example 1 except that the conductive film forming composition 1 was changed to the conductive film forming composition 2 (Example 13) or the conductive film forming composition 3 (Example 15). The sex coating film was formed on a glass substrate, and the solution A was dip-coated on the formed insulating coating film.
Then, in the same manner as in Example 1, the coating film dip-coated with the solution A is heated in the air at 150 ° C. for 1 minute, and then in the air at 300 ° C. for 1 minute to form a conductive film. Manufactured.
The volume resistance value of the produced conductive film was measured in the same manner as in Example 1. Table 3 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Example 13 ... Copper (0) 89.9%, cuprous chloride 10.0%, cuprous oxide 0.1%
Example 15 ... Copper (0) 86.0%, cuprous chloride 9.1%, cuprous oxide 4.9%

[Example 14]
A conductive film was produced in the same manner as in Example 10 except that the conductive film forming composition 1 was changed to the conductive film forming composition 3.
The volume resistance value of the produced conductive film was measured in the same manner as in Example 1. Table 3 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Example 14 ... Copper (0) 90.0%, cuprous chloride 8.9%, cuprous oxide 1.1%

[Example 16]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1.
Solution A was dip-coated on the formed insulating coating film in the same manner as in Example 1. After dip-coating the solution A, a second dip-coat was performed in the same manner.
Then, the coating film obtained by dipping the solution A twice is heated in the air at 150 ° C. for 1 minute in the same manner as in Example 1, and then heated in the air at 300 ° C. for 1 minute to conduct conductivity. A membrane was manufactured.
The volume resistance value of the produced conductive film was measured in the same manner as in Example 1. Table 3 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Example 16 ... Copper (0) 63.9%, cuprous chloride 5.2%, cuprous oxide 30.8%

[Comparative Examples 1 to 8]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1.
The substrate on which the insulating coating film was formed was subjected to solution A (Comparative Example 1), solution B (Comparative Example 2), solution C (Comparative Example 3), solution D (Comparative Example 4), and solution E (Comparative Example 4) in the air. Example 5), solution F (Comparative Example 6), solution G (Comparative Example 7) or solution H (Comparative Example 8) was immersed for 5 seconds and dip-coated.
Then, as shown in Table 4, the coating film dip-coated with any of the solutions A to H was heated in the air at 150 ° C. for 1 minute to produce a film.
The volume resistance value of the produced film was measured in the same manner as in Example 1. Table 4 shows the measured volume resistance values.

The results of elemental analysis by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) of the cross section of the conductive film in the thickness direction under the above-mentioned conditions are as shown below.
Comparative Example 1: Copper area ratio 66.1%, void area ratio 33.9%

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Comparative Example 4: Copper (0) 67.4%, cuprous chloride 32.6%, cuprous oxide 0.0%

[Comparative Example 9]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1.
The substrate on which the insulating coating film was formed was immersed in Solution I (without halogen compounds) for 5 seconds in the air and dip-coated.
Then, in the same manner as in Comparative Example 1, the coating film dip-coated with Solution I was heated in the air at 150 ° C. for 1 minute to produce a film, as shown in Table 4.
The volume resistance value of the produced film was measured in the same manner as in Example 1. Table 4 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Comparative Example 9: Copper (0) 100.0%, cuprous oxide 0.0%

[Comparative Examples 10 to 12]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1, and the formed insulating coating film was dip-coated with Solution I (which does not contain a halogen compound).
Then, the coating film dip-coated with the solution I was heated at 150 ° C. for 1 minute in the air, and then 180 ° C. (Comparative Example 10) and 250 ° C. (Comparative Example 11) in the air as shown in Table 4. ) Or 300 ° C. (Comparative Example 12) for 1 minute to produce a film.
The volume resistance value of the produced film was measured in the same manner as in Example 1. Table 4 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Comparative Example 10: Copper (0) 100.0%, cuprous oxide 0.0%
Comparative Example 11 ... Copper (0) 95.5%, cuprous oxide 4.5%
Comparative Example 12 ... Copper (0) 56.4%, cuprous oxide 43.6%

[Comparative Example 13]
An insulating coating film was formed on the glass substrate in the same manner as in Example 1, and the formed insulating coating film was dip-coated with Solution I (which does not contain a halogen compound).
Then, the coating film dip-coated with Solution I was heated in the air at 150 ° C. for 1 minute, and then in the air at 300 ° C. for 5 minutes as shown in Table 4, to produce a film.
The volume resistance value of the produced film was measured in the same manner as in Example 1. Table 4 shows the measured volume resistance values.

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Comparative Example 13 ... Copper (0) 65.1%, cuprous oxide 34.9%

[Comparative Example 14]
An insulating coating film was produced on a glass substrate in the same manner as in Example 1.
The volume resistance value of the produced insulating coating film was measured in the same manner as in Example 1. Table 4 shows the measured volume resistance values.

The results of elemental analysis by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) of the cross section of the conductive film in the thickness direction under the above-mentioned conditions are as shown below.
Comparative Example 14: Copper area ratio 66.2%, void area ratio 33.8%

The results of the quantitative analysis by the X-ray diffraction analysis under the above-mentioned conditions are as shown below.
Comparative Example 14: Copper (0) 100.0%, cuprous oxide 0.0%

In the examples and comparative examples herein, the measurement limit of the volume resistivity is 1.0 × 10 ⁴ Ω · cm, if it exceeds this as outside the measurement range, "OL volume resistivity Was displayed.

The conductive films produced in Examples 1 to 16 had a low volume resistance value and had excellent conductivity.

From the comparison between Examples 1 to 4 and Examples 5 to 8, it was found that, as a halogen compound, hydrogen chloride tends to produce a conductive film having better conductivity than hydrogen bromide.

From the comparison of Examples 1, 9 and 10, it was found that the higher the heating temperature in the heating step, the more likely it is that a conductive film having better conductivity can be produced. However, no significant difference in conductivity was observed between Example 10 having a heating temperature of 250 ° C. and Example 1 having a heating temperature of 300 ° C.

From the comparison between Examples 1 and 11, it was found that the longer the heating time in the heating step, the more likely it is that a conductive film having better conductivity can be produced.

From the comparison between Example 1 and Example 12, there is a tendency that the heating in the heating step can produce a conductive film having better conductivity by omitting the preliminary heating and performing the final heating. It turned out that there was.

From the comparison of Examples 1, 13 and 15, it was found that the inclusion of the additive tends to produce a conductive film having better conductivity. Further, it was found that trimethylolpropane as an additive tends to be able to produce a conductive film having better conductivity than vinylpyrrolidone p.

From the comparison between Example 1 and Example 16, it was found that there is a tendency that a conductive film having more excellent conductivity can be produced by performing the contact step a plurality of times.

Comparative Examples 1 to 8 were comparative examples in which heating at 180 ° C. or higher in the heating step was omitted, and the conductivity of the produced film was poor.

Comparative Examples 9 to 13 are comparative examples in which the insulating coating film and the liquid containing no halogen compound were brought into contact in the contacting step, that is, the insulating coating film and the halogen compound were not brought into contact in the contacting step. be.
In each case, the conductivity of the produced film was poor.

Comparative Example 14 is the insulating coating film itself. The conductivity was poor.

Claims (13)

A contact step in which an insulating coating film containing copper particles is brought into contact with a halogen compound, and a first heating method in which the coating film obtained in the contacting step is heated at a temperature of 150 ° C. or lower, and the first heating coating. A method for producing a conductive film, comprising a heating step including a second heating in which the film is heated at a temperature of 180 ° C. or higher in an oxidizing atmosphere. The production method according to claim 1 , wherein the temperature of the second heating is 250 ° C. or higher. The production method according to claim 1 or 2 , wherein the temperature of the second heating is 300 ° C. or higher. The production method according to any one of claims 1 to 3 , wherein the temperature of the second heating is 500 ° C. or lower. The production method according to any one of claims 1 to 4 , wherein the temperature of the second heating is 350 ° C. or lower. The production method according to any one of claims 1 to 5 , wherein the temperature of the first heating is 100 ° C. to 150 ° C. The production method according to any one of claims 1 to 6 , wherein in the first heating, the heating time at the temperature is 5 seconds to 10 minutes. The production method according to any one of claims 1 to 7 , wherein in the second heating, the heating time at the temperature is 5 seconds to 10 minutes. The production method according to any one of claims 1 to 8 , wherein the oxidizing atmosphere is the atmosphere. The method according to any one of claims 1 to 9 , wherein when the insulating coating film and the halogen compound are brought into contact with each other in the contacting step, the insulating coating film and the solution containing the halogen compound are brought into contact with each other. Manufacturing method. The production method according to any one of claims 1 to 10 , wherein the halogen compound is hydrogen halide. A conductive film containing copper, cuprous oxide, and cuprous halide.
The area ratio of copper obtained by elemental analysis by scanning electron microscope-energy dispersive X-ray spectroscopy of the cross section in the thickness direction of the conductive film is 70% or more, and
Wherein the content of copper and cuprous oxide obtained by quantitative analysis by X-ray diffraction analysis of the surface of the conductive film, the content of copper is rather multi than the content of cuprous oxide,
Regarding the contents of cuprous oxide and cuprous halide obtained by quantitative analysis by X-ray diffraction analysis of the surface of the conductive film, the content of cuprous oxide is higher than the content of cuprous halide. There are many conductive films. The conductive film according to claim 12, wherein the area ratio of copper is 85% or more.

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