Method for manufacturing conductive film and method for manufacturing electromagnetic wave shield

Abstract

The present invention addresses the problem of providing a method for producing a conductive film having excellent adhesion. The present invention also addresses the problem of providing a method for manufacturing an electromagnetic wave shield. A method for producing a conductive film according to the present invention comprises: a step 1 for forming a coating film by applying an ink containing at least one of a metal salt and a complex; a step 2 in which the coating film is irradiated with light; and a step 3 for obtaining a conductive film by applying a light irradiation treatment to the coating film obtained in the step 2, the wavelength WL2 having the maximum intensity among the irradiation light of the light irradiation treatment in the step 2 and the wavelength WL3 having the maximum intensity among the irradiation light of the light irradiation treatment in the step 3 satisfying WL2 < WL3, the wavelength WL2 having the maximum intensity among the irradiation light of the light irradiation treatment in the step 3 satisfying WL2 < WL3, and the wavelength WL3 having the maximum intensity among the irradiation light of the light irradiation treatment in the step 2. The exposure amount EA2 of the light irradiation treatment in step 2 and the exposure amount EA3 of the light irradiation treatment in step 3 satisfy EA2 < EA3.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a conductive film and a method for manufacturing an electromagnetic wave shielding body. Background Art

[0002] Semiconductor devices and the like may be hindered from operating normally due to interference caused by electromagnetic waves, resulting in the possibility of failure. In addition, when semiconductor devices and the like generate electromagnetic waves, the electromagnetic waves may interfere with other semiconductor devices or electronic parts, also possibly hindering normal operation.

[0003] In order to avoid interference caused by electromagnetic waves from other electronic devices or to avoid interference caused by electromagnetic waves to other electronic devices, it is necessary to shield electromagnetic waves. As a technology for shielding electromagnetic waves, for example, a technology is known to form an electromagnetic wave shield by laminating an insulating film and a conductive film containing a conductive component on a printed wiring board on which a semiconductor device is mounted.

[0004] Furthermore, as a technique for forming a conductive film containing a conductive component, a method of forming a conductive film by an inkjet recording method using a conductive ink containing a metal component is widely known.

[0005] As a technology for forming a conductive film, for example, Patent Document 1 discloses a technology related to the following manufacturing method: a matrix containing a material formed in a pattern on a substrate is coated on the substrate, an energy beam is irradiated to cause it to collide at the position of the pattern, and the matrix is ​​heated sufficiently along the pattern wiring to make the above-mentioned material adhere to the above-mentioned substrate without completely sintering the above-mentioned material in the wiring, thereby fixing the pattern on the above-mentioned matrix, removing the matrix remaining on the above-mentioned substrate outside the fixed pattern, and after removing the above-mentioned matrix, sintering the above-mentioned material in the above-mentioned pattern.

[0006] Previous technical literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application No. 2016-516211 Summary of the invention

[0009] Technical issues to be solved by the invention

[0010] The conductive film formed by the inkjet recording method using the conductive ink is required to have further improved physical properties such as adhesion.

[0011] The present inventors have further studied the method for producing a conductive film containing a metal component with reference to the technology described in Patent Document 1. As a result, they have found that the adhesiveness performance of the obtained conductive film sometimes does not reach the required level and there is room for improvement.

[0012] In view of the above-mentioned actual situation, an object of the present invention is to provide a method for producing a conductive film having excellent adhesion. In addition, an object of the present invention is to provide a method for producing an electromagnetic shield.

[0013] Means for solving technical problems

[0014] As a result of intensive studies on the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by the following configuration.

[0015] [1] A method for manufacturing a conductive film, comprising: step 1, applying an ink containing at least one of a metal salt and a complex to form a coating film; step 2, subjecting the coating film to light irradiation treatment; and step 3, subjecting the coating film obtained in the step 2 to light irradiation treatment to obtain a conductive film, wherein the wavelength WL2 with the highest intensity in the light irradiation treatment in the step 2 and the wavelength WL3 with the highest intensity in the light irradiation treatment in the step 3 satisfy WL2<WL3, and the exposure amount EA2 of the light irradiation treatment in the step 2 and the exposure amount EA3 of the light irradiation treatment in the step 3 satisfy EA2 <EA3。

[0016] [2] The method for producing a conductive film according to [1], wherein:

[0017] The exposure amount EA2 of the light irradiation treatment in the step 2 and the exposure amount EA3 of the light irradiation treatment in the step 3 satisfy EA3 / FA2>3.

[0018] [3] The method for producing a conductive film according to [1] or [2], wherein:

[0019] In the coating film obtained in the step 2, the ratio of the content of the reduced metal to the total mass of the metal is 50% by mass or more.

[0020] [4] The method for producing a conductive film according to any one of [1] to [3], wherein:

[0021] In the step 1, the ink is applied in such an amount that the thickness of the conductive film becomes 2 μm or less.

[0022] [5] The method for producing a conductive film according to any one of [1] to [4], wherein:

[0023] The elapsed time from the completion of the light irradiation treatment in the step 2 to the start of the light irradiation treatment in the step 3 is within 60 seconds.

[0024] [6] The method for producing a conductive film according to any one of [1] to [5], wherein:

[0025] The wavelength WL2 and the wavelength WL3 satisfy WL3-WL2>50nm.

[0026] [7] The method for producing a conductive film according to any one of [1] to [6], wherein:

[0027] The ink contains at least one of a silver salt and a silver complex.

[0028] [8] A method for producing an electromagnetic shield, comprising the step of forming a conductive film on a substrate according to the method for producing a conductive film according to any one of [1] to [7].

[0029] Effects of the Invention

[0030] According to the present invention, a method for producing a conductive film having excellent adhesion can be provided. Also, according to the present invention, a method for producing an electromagnetic shield can be provided. DETAILED DESCRIPTION

[0031] Hereinafter, the present invention will be described in detail.

[0032] The following description is made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.

[0033] In this specification, the numerical range represented by "~" refers to a range that includes the numerical values ​​recorded before and after "~" as the lower limit and upper limit. In the numerical range recorded in stages in this specification, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical range recorded in this specification, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the value shown in the embodiment.

[0034] In this specification, each component may be used alone or in combination of two or more substances. When two or more substances are used for each component, the content of the component refers to the total content of the two or more substances unless otherwise specified.

[0035] In the present specification, a combination of two or more preferred aspects is a more preferred aspect.

[0036] In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0037] In this specification, "g" means "mass g".

[0038] In this specification, "pL" means "picoliter". 1pL is equal to 10-12 L.

[0039] In this specification, angles represented by specific numerical values ​​and expressions such as "parallel", "perpendicular", and "orthogonal" include an error range generally allowed in the technical field unless otherwise specified.

[0040] In this specification, "conductive" means a volume resistivity of less than 10 8 Properties of Ωcm.

[0041] [Method for producing conductive film]

[0042] The method for manufacturing a conductive film of the present invention (hereinafter also referred to as "the present manufacturing method") comprises: step 1, applying an ink containing at least one of a metal salt and a complex to form a coating film; step 2, subjecting the coating film to light irradiation treatment; and step 3, subjecting the coating film obtained in the above step 2 to light irradiation treatment to obtain a conductive film.

[0043] In addition, in the present manufacturing method, the wavelength WL2 having the largest intensity among the irradiation light of the light irradiation treatment in the step 2 and the wavelength WL3 having the largest intensity among the irradiation light of the light irradiation treatment in the step 3 satisfy WL2<WL3, and the exposure amount EA2 of the light irradiation treatment in the step 2 and the exposure amount EA3 of the light irradiation treatment in the step 3 satisfy EA2<WL3. <EA3。

[0044] According to the present manufacturing method, a conductive film with excellent adhesion can be manufactured. Although the details of the reason are not clear, in the present manufacturing method, after exposing the coating film containing the above-mentioned metal salt or metal complex to light on the shorter wavelength side with a smaller exposure amount, it is exposed to light on the longer wavelength side with a larger exposure amount, thereby suppressing the shaking of the coating film during the period from the implementation of the light irradiation treatment to the curing of the entire coating film. As a result, it is inferred that a conductive film with a more uniform metal density in the depth direction of the conductive film and better adhesion can be manufactured.

[0045] Hereinafter, each step of the present production method will be described in detail.

[0046] In this specification, a coating film formed in step 1 and not subjected to the light irradiation treatment in step 2 is also referred to as “coating film A”, and a coating film subjected to the light irradiation treatment in step 2 and not subjected to the light irradiation treatment in step 3 is also referred to as “coating film B”.

[0047] [Process 1]

[0048] Step 1 is a step of forming a coating film A by applying ink containing at least one of a metal salt and a complex (hereinafter also referred to as “conductive ink”).

[0049] <Conductive Ink>

[0050] The conductive ink will be described below.

[0051] The conductive ink is, for example, an ink composition in which at least one selected from the group consisting of metal salts and metal complexes is dissolved in a solvent, and is used to form a film having conductivity (ie, a conductive film).

[0052] As the metal contained in the conductive ink, for example, silver, gold, platinum, nickel, palladium and copper are preferably mentioned, and silver or copper is more preferably silver. That is, the conductive ink preferably contains at least one of the salts and complexes of at least one metal selected from the group consisting of silver, gold, platinum, nickel, palladium and copper, more preferably contains at least one selected from the group consisting of silver salts, silver complexes, copper salts and copper complexes, and further preferably contains at least one of silver salts and silver complexes.

[0053] In the present production method, one metal salt or complex may be used alone, or two or more selected from the group consisting of metal salts and complexes may be used in combination.

[0054] The content (total content) of the metal salt and the metal complex contained in the conductive ink is preferably 1 to 40% by mass, more preferably 5 to 30% by mass, and further preferably 7 to 20% by mass, in terms of metal element conversion relative to the total mass of the conductive ink. If the content of the metal salt and the metal complex contained in the conductive ink is within the above range, the conductivity and the ejection property of the inkjet recording method are more excellent.

[0055] Hereinafter, the metal salt and the metal complex contained in the conductive ink will be described in detail.

[0056] (Metal Salt)

[0057] Examples of the metal salt contained in the conductive ink include metal benzoates, halides, carbonates, citrates, iodates, nitrites, nitrates, acetates, phosphates, sulfates, sulfides, trifluoroacetates, and carboxylates. Two or more salts may be used in combination.

[0058] The metal salt is preferably a metal carboxylate, and more preferably a metal carboxylate of at least one metal selected from the group consisting of silver, gold, platinum, nickel, palladium, and copper, from the viewpoint of conductivity and storage stability.

[0059] The carboxylic acid forming the metal carboxylate is preferably at least one selected from the group consisting of formic acid and carboxylic acids having 1 to 30 carbon atoms, more preferably a carboxylic acid having 8 to 20 carbon atoms, and further preferably a fatty acid having 8 to 20 carbon atoms. The fatty acid may be linear or branched and may have a substituent.

[0060] Examples of the straight-chain fatty acid include acetic acid, propionic acid, butyric acid, valeric acid, pentanoic acid, hexanoic acid, heptanoic acid, behenic acid, oleic acid, octanoic acid, nonanoic acid, decanoic acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, and undecanoic acid.

[0061] Examples of the branched-chain fatty acid include isobutyric acid, isovaleric acid, ethylhexanoic acid, neodecanoic acid, neopentanoic acid, 2-methylvaleric acid, 3-methylvaleric acid, 4-methylvaleric acid, 2,2-dimethylbutyric acid, 2,3-dimethylbutyric acid, 3,3-dimethylbutyric acid, and 2-ethylbutyric acid.

[0062] Examples of the carboxylic acid having a substituent include hexafluoroacetylaceruvic acid, hydroangelica acid, 3-hydroxybutyric acid, 2-methyl-3-hydroxybutyric acid, 3-methoxybutyric acid, acetone dicarboxylic acid, 3-hydroxyglutaric acid, 2-methyl-3-hydroxyglutaric acid, and 2,2,4,4-hydroxyglutaric acid.

[0063] The metal salt may be a commercially available product or may be a metal salt produced by a known method. The production method of the metal salt will be described below using a silver salt as an example.

[0064] First, a silver compound (e.g., silver acetate) serving as a silver supply source and an amount of formic acid or a fatty acid having 1 to 30 carbon atoms equal to the molar equivalent of the silver compound are added to an organic solvent such as ethanol. The mixture is stirred for a predetermined time using an ultrasonic stirrer, and the resulting precipitate is washed with ethanol and decanted. All of these steps can be performed at room temperature. The mixing ratio of the silver compound to formic acid or a fatty acid having 1 to 30 carbon atoms is preferably 1:2 to 2:1, more preferably 1:1, in terms of molar ratio.

[0065] (Metal Complex)

[0066] The metal complex contained in the conductive ink is obtained, for example, by reacting a metal salt with a complexing agent. As a method for producing the metal complex, for example, a method of adding a metal salt and a complexing agent to an organic solvent and stirring for a predetermined time can be cited. The stirring method is not particularly limited and can be appropriately selected from known methods such as a method of stirring using a stirrer, a stirring blade or a mixer and a method of applying ultrasonic waves.

[0067] Examples of the metal salt for forming the metal complex include metal oxides, thiocyanates, sulfides, chlorides, cyanides, cyanates, carbonates, acetates, nitrates, nitrites, sulfates, phosphates, perchlorates, tetrafluoroborate, acetylacetonate complexes, and carboxylates.

[0068] The metal complex has a structure derived from the complexing agent.

[0069] As the complexing agent, amines, ammonium carbamate compounds, ammonium carbonate compounds, ammonium bicarbonate compounds and carboxylic acids can be cited. Among them, from the aspects of conductivity and stability of the metal complex, the complexing agent preferably contains at least one selected from the group consisting of ammonium carbamate compounds, ammonium carbonate compounds, alkylamines and carboxylic acids having 8 to 20 carbon atoms.

[0070] Examples of the amine as the complexing agent include ammonia, primary amines, secondary amines, tertiary amines, and polyamines.

[0071] Examples of the primary amine having a linear alkyl group include methylamine, ethylamine, 1-propylamine, n-butylamine, n-pentylamine, n-hexylamine, heptylamine, octylamine, nonylamine, n-decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine and octadecylamine.

[0072] Examples of the primary amine having a branched alkyl group include isopropylamine, sec-butylamine, tert-butylamine, isopentylamine, 2-ethylhexylamine, and tert-octylamine.

[0073] Examples of the primary amine having an alicyclic structure include cyclohexylamine and dicyclohexylamine.

[0074] Examples of the primary amine having a hydroxyalkyl group include ethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, propanolamine, isopropanolamine, dipropanolamine, diisopropanolamine, tripropanolamine, and triisopropanolamine.

[0075] Examples of the primary amine having an aromatic ring include benzylamine, N,N-dimethylbenzylamine, aniline, diphenylamine, triphenylamine, aniline, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, 4-aminopyridine, and 4-dimethylaminopyridine.

[0076] Examples of the secondary amine include dimethylamine, diethylamine, dipropylamine, dibutylamine, diphenylamine, dicyclopentylamine, and methylbutylamine.

[0077] Examples of the tertiary amine include trimethylamine, triethylamine, tripropylamine, and triphenylamine.

[0078] Examples of the polyamine include ethylenediamine, 1,3-diaminopropane, diethylenetriamine, triethylenetetramine, tetramethylenepentamine, hexamethylenediamine, tetraethylenepentamine, and combinations thereof.

[0079] The amine is preferably an alkylamine, more preferably an alkylamine having 3 to 10 carbon atoms, and still more preferably a primary alkylamine having 4 to 10 carbon atoms.

[0080] The amines constituting the metal complex may be one type or two or more types.

[0081] When the metal salt and the amine are reacted, the ratio of the amount of the amine to the amount of the metal salt is preferably 1 to 15 times, more preferably 1.5 to 6 times. When the ratio is within the above range, the complex formation reaction is terminated to obtain a transparent solution.

[0082] Examples of the ammonium carbamate compound as the complexing agent include ammonium carbamate, methylammonium methylcarbamate, ethylammonium ethylcarbamate, 1-propylammonium 1-propylcarbamate, isopropylammonium isopropylcarbamate, butylammonium butylcarbamate, isobutylammonium isobutylcarbamate, amylammonium amylcarbamate, hexylammonium hexylcarbamate, heptylammonium heptylcarbamate, octylammonium octylcarbamate, 2-ethylhexylammonium 2-ethylhexylcarbamate, nonylammonium nonylcarbamate, and decylammonium decylcarbamate.

[0083] Examples of ammonium carbonate compounds as complexing agents include ammonium carbonate, methylammonium carbonate, ethylammonium carbonate, 1-propylammonium carbonate, isopropylammonium carbonate, butylammonium carbonate, isobutylammonium carbonate, pentylammonium carbonate, hexylammonium carbonate, heptylammonium carbonate, octylammonium carbonate, 2-ethylhexylammonium carbonate, nonylammonium carbonate, and decylammonium carbonate.

[0084] Examples of the ammonium bicarbonate compound as the complexing agent include ammonium bicarbonate, methylammonium bicarbonate, ethylammonium bicarbonate, 1-propylammonium bicarbonate, isopropylammonium bicarbonate, butylammonium bicarbonate, isobutylammonium bicarbonate, pentylammonium bicarbonate, hexylammonium bicarbonate, heptylammonium bicarbonate, octylammonium bicarbonate, 2-ethylhexylammonium bicarbonate, nonylammonium bicarbonate and decylammonium bicarbonate.

[0085] When reacting a metal salt with an ammonium carbamate compound, an ammonium carbonate compound or an ammonium bicarbonate compound, the ratio of the amount of the ammonium carbamate compound, the ammonium carbonate compound or the ammonium bicarbonate compound to the amount of the metal salt is preferably 0.01 to 1 times, more preferably 0.05 to 0.6 times.

[0086] Examples of the complexing agent, i.e., carboxylic acid, include caproic acid, caprylic acid, nonanoic acid, 2-ethylhexanoic acid, capric acid, neodecanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, palmitoleic acid, oleic acid, linoleic acid, and linolenic acid. Among them, the carboxylic acid is preferably a carboxylic acid having 8 to 20 carbon atoms, and more preferably a carboxylic acid having 10 to 16 carbon atoms.

[0087] (Optional ingredient)

[0088] -Solvents-

[0089] The conductive ink preferably contains a solvent. The solvent is not particularly limited as long as it can dissolve components contained in the conductive ink, such as metal salts and metal complexes.

[0090] From the viewpoint of ease of production, the boiling point of the solvent is preferably 30 to 300°C, more preferably 50 to 200°C, and even more preferably 50 to 150°C.

[0091] The solvent is preferably contained in the conductive ink so that the metal ion concentration relative to the total content of the metal salt and the metal complex (the amount of the metal present as free ions relative to 1 g of the metal salt or the metal complex) is 0.01 to 3.6 mmol / g, and more preferably 0.05 to 2 mmol / g. When the metal ion concentration is within the above range, the conductive ink has excellent fluidity and exhibits excellent conductivity.

[0092] Examples of the solvent include hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, carbamates, olefins, amides, ethers, esters, alcohols, thiols, thioethers, phosphines, and water. The conductive ink may contain only one solvent or two or more solvents.

[0093] The hydrocarbon is preferably a linear or branched hydrocarbon having a carbon number of 6 to 20. Examples of the hydrocarbon include pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, octadecane, nonadecane and eicosane.

[0094] The alicyclic hydrocarbon is preferably an alicyclic hydrocarbon having a carbon number of 6 to 20. Examples of the alicyclic hydrocarbon include cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, and decalin.

[0095] Examples of the aromatic hydrocarbon include benzene, toluene, xylene, and tetralin.

[0096] The ether may be any of a linear ether, a branched ether, and a cyclic ether. Examples of the ether include diethyl ether, dipropyl ether, dibutyl ether, methyl-tert-butyl ether, tetrahydrofuran, tetrahydropyran, dihydropyran, and 1,4-dioxane.

[0097] The alcohol may be any of a primary alcohol, a secondary alcohol and a tertiary alcohol.

[0098] Examples of the alcohol include ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, 1-octanol, 2-octanol, 3-octanol, tetrahydrofurfuryl alcohol, cyclopentanol, terpineol, decanol, isodecanol, lauryl alcohol, isolauryl alcohol, myristyl alcohol, isomyristyl alcohol, cetyl alcohol, isocetyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, isooleyl alcohol, linolenyl alcohol, isolinolenyl alcohol, palmityl alcohol, isopalmityl alcohol, eicosanol, and isoeicosanol.

[0099] Examples of the ketone include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

[0100] Examples of the esters include methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, methoxybutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate and 3-methoxybutyl acetate.

[0101] -reducing agent-

[0102] The conductive ink may contain a reducing agent. If the conductive ink contains a reducing agent, the reduction from the metal salt or metal complex to the metal is promoted.

[0103] Examples of the reducing agent include metal borohydride salts, aluminum hydride salts, amine compounds, alcohols, organic acids, reducing sugars, sugar alcohols, sodium sulfite, hydrazine compounds, dextrin, hydroquinone, hydroxylamine, ethylene glycol, glutathione, and oxime compounds.

[0104] The reducing agent may also be an oxime compound described in Japanese Patent Application No. 2014-516463. Examples of the oxime compound include acetone oxime, cyclohexanone oxime, 2-butanone oxime, 2,3-butanedione monoxime, dimethylglyoxime, methyl acetoacetate monoxime, methyl pyruvate monoxime, benzaldehyde oxime, 1-indanone oxime, 2-adamantanone oxime, 2-methylbenzamide oxime, 3-methylbenzamide oxime, 4-methylbenzamide oxime, 3-aminobenzamide oxime, 4-aminobenzamide oxime, acetophenone oxime, benzamide oxime, and pinacolone oxime.

[0105] The reducing agent contained in the conductive ink may be one kind or two or more kinds.

[0106] The content of the reducing agent in the conductive ink is not particularly limited, but is preferably 0.1 to 20% by mass, more preferably 0.3 to 10% by mass, and further preferably 1 to 5% by mass, based on the total mass of the conductive ink.

[0107] -Resin-

[0108] The conductive ink may contain a resin. If the conductive ink contains a resin, the adhesion between the conductive ink and the substrate and the like is improved.

[0109] Examples of the resin include polyester, polyethylene, polypropylene, polyacetal, polyolefin, polycarbonate, polyamide, fluororesin, silicone resin, ethyl cellulose, hydroxyethyl cellulose, rosin, acrylic resin, polyvinyl chloride, polysulfone, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl resin, polyacrylonitrile, polysulfide, polyamideimide, polyether, polyarylate, polyetheretherketone, polyurethane, epoxy resin, vinyl ester resin, phenolic resin, melamine resin and urea resin.

[0110] The resin contained in the conductive ink may be one kind or two or more kinds.

[0111] The conductive ink may further contain additives such as inorganic salts, organic salts, inorganic oxides such as silicon dioxide, surface conditioners, wetting agents, crosslinking agents, antioxidants, rust inhibitors, heat stabilizers, surfactants, plasticizers, curing agents, thickeners, and silane coupling agents within a range that does not impair the effects of the present invention. In the conductive ink, the total content of the additives is preferably 20% by mass or less relative to the total mass of the conductive ink.

[0112] (Absorbance)

[0113] From the viewpoint that the effect of the present invention can be further exerted, and the ejection property of the inkjet recording method is excellent and the unevenness of the film surface of the conductive film (the unevenness of the surface of the conductive film) can be suppressed, the conductive ink used in the present production method preferably has an absorbance of 1 or less at a wavelength of 350 to 450 nm with an optical path length of 10 mm, and more preferably 0.8 or less. The lower the absorbance of the conductive ink, the higher the solubility of the metal salt and the metal complex, and the less the content of metal particles such as metal nanoparticles.

[0114] The lower limit of the absorbance of the conductive ink is not particularly limited, and is, for example, 0.01 or more.

[0115] In this specification, the absorbance of the conductive ink is measured by a known method using an ultraviolet-visible-infrared spectrophotometer (for example, "V700" manufactured by JASCO CORPORATION).

[0116] (Other properties of conductive ink)

[0117] The viscosity of the conductive ink is not particularly limited, but is preferably 0.001 to 5000 Pa·s, and more preferably 0.001 to 100 Pa·s.

[0118] When the coating film A is formed by spray coating or inkjet recording, the viscosity of the conductive ink is preferably 1 to 100 mPa·s, more preferably 2 to 50 mPa·s, and even more preferably 3 to 30 mPa·s.

[0119] The viscosity of the conductive ink is a value measured using a viscometer at 25° C. The viscosity is measured using, for example, a VISCOMETER TV-22 viscometer (manufactured by TOKI SANGYO CO., LTD.).

[0120] The surface tension of the conductive ink is not particularly limited, but is preferably 20 to 45 mN / m, and more preferably 25 to 35 mN / m.

[0121] The surface tension is a value measured using a surface tensiometer at 25° C. The surface tension is measured using, for example, DY-700 (manufactured by Kyowa Interface Science Co., Ltd.).

[0122] (Preparation of Conductive Ink)

[0123] The method for preparing the conductive ink is not particularly limited, and the conductive ink can be prepared by synthesizing and / or blending the constituent components of the conductive ink by a known method.

[0124] Furthermore, in the present production method, it is also possible to use a conductive ink obtained by purchase or the like.

[0125] <Formation of coating film>

[0126] As a method of forming the coating film A using the conductive ink, for example, there can be mentioned a method of forming the coating film A by applying the conductive ink on a substrate.

[0127] The coating film A may be formed to contact the surface of the substrate, or may be formed to contact other layers when other layers (such as an insulating film described below) are provided on the substrate. That is, the coating film A may be provided directly on the surface of the substrate, or may be provided on the substrate via other layers.

[0128] The method of applying the conductive ink to the substrate is not particularly limited, and the conductive ink can be applied by known methods such as inkjet recording, spraying, bar coating, and dipping. Among them, it is preferred to apply the conductive ink by inkjet recording because a small amount of droplets can be sprayed to reduce the thickness of the conductive film.

[0129] The thickness of the coating film A is selected according to the composition of the conductive ink and the thickness of the conductive film to be produced, but is preferably 0.1 to 500 μm, 0.2 to 200 μm, for example.

[0130] The thickness of the coating film A can be adjusted by the amount of conductive ink applied (in the case of inkjet recording, the amount of droplet ejection and the resolution).

[0131] Furthermore, the thickness of the coating film A can be calculated from the amount of the conductive ink applied and the area of ​​the coating film A formed.

[0132] (Inkjet recording method)

[0133] The inkjet recording method can be any of a charge control method that utilizes electrostatic attraction to eject ink, a drop-on-demand method (pressure pulse method) that utilizes the vibration pressure of a piezoelectric element, an acoustic wave inkjet method that converts an electrical signal into a sound beam and irradiates the ink and ejects the ink using radiation pressure, and a thermal induction inkjet (Bubble Jet (registered trademark)) method that heats the ink to form bubbles and utilizes the generated pressure.

[0134] As an inkjet recording method, the inkjet recording method described in Japanese Patent Application Laid-Open No. 54-059936 can be particularly effectively used. Ink undergoes a rapid volume change due to thermal energy, and the ink is ejected from a nozzle by a force based on the state change.

[0135] In addition, regarding the inkjet recording method, the method described in paragraphs 0093 to 0105 of Japanese Patent Application Laid-Open No. 2003-306623 can also be referred to.

[0136] Examples of inkjet heads used in inkjet recording methods include a shuttle method that uses a short serial head to scan the head in the width direction of the substrate and perform recording, and a line method that uses a line head in which recording elements are arranged over the entire area of ​​one side of the substrate.

[0137] In the row-column method, by scanning the substrate in a direction intersecting the arrangement direction of the recording elements, a pattern can be formed on the entire surface of the substrate, and a transport system such as a carriage for scanning a short-sized head is not required. In addition, since there is no need to move the carriage or perform complex scanning control with the substrate, only the substrate is moved, so the formation speed can be increased compared to the reciprocating method.

[0138] The ejection amount of droplets of the conductive ink ejected from the inkjet head is preferably 1 to 100 pL, more preferably 3 to 80 pL, and even more preferably 3 to 20 pL.

[0139] The temperature of the substrate when applying the conductive ink to the substrate is preferably 20 to 120° C., more preferably 40 to 80° C. When the substrate temperature is 20 to 120° C., the influence of substrate deformation due to heat is small, and drying of the coating film is accelerated.

[0140] <Base Material>

[0141] In step 1, it is preferred that a coating film A of a conductive ink is formed on a substrate.

[0142] As the substrate for forming the coating film A, a known substrate can be used.

[0143] The material of the substrate is not particularly limited and can be selected according to the purpose. As the material of the substrate, for example, synthetic resins such as polyimide, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, polyurethane, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, acrylic resin, AS resin (acrylonitrile styrene resin), ABS resin (acrylonitrile-butadiene-styrene copolymer), triacetyl cellulose, polyamide, polyacetal, polyphenylene sulfide, polysulfone, epoxy resin, glass epoxy resin (impregnated resin formed by impregnating epoxy resin into glass fiber), melamine resin, phenolic resin, urea resin, alkyd resin, fluororesin and polylactic acid; inorganic materials such as copper, steel, aluminum, silicon, soda glass, alkali-free glass and indium tin oxide (ITO); and paper such as base paper, coated paper, coated paper, cast-coated paper, resin-coated paper and synthetic paper.

[0144] The substrate may be a single layer or may be two or more layers. When the substrate is two or more layers, two or more substrates made of different materials may be stacked.

[0145] The form of the substrate is preferably a sheet or a film.

[0146] The thickness of the substrate is preferably 20 to 10000 μm. When the thickness of the substrate is 20 μm or more, the conductive film can be stably maintained, and the handleability of the conductor formed with the conductive film also becomes good.

[0147] The substrate may have an ink receiving layer. The ink receiving layer refers to a coating layer formed on the substrate in order to absorb ink and fix the ink.

[0148] The thickness of the ink receiving layer is preferably 1 to 20 μm. If the thickness of the ink receiving layer is 1 to 20 μm, the ink receiving layer can be more stably maintained, the uniformity of wetting and diffusion of the conductive ink is improved, and the quality of the conductive film is further improved.

[0149] Before applying the conductive ink to the substrate, the substrate may be pretreated. Examples of the pretreatment include ozone treatment, plasma treatment, corona treatment, primer treatment, and roughening treatment.

[0150] The substrate may be a substrate for a printed wiring board.

[0151] Examples of the printed wiring board substrate include electronic substrates on which electronic components are mounted. Examples of the electronic substrate include flexible printed substrates, rigid printed substrates, and rigid-flexible substrates formed of the above substrates.

[0152] Examples of electronic components include semiconductor devices, capacitors, transistors, and ground wiring.

[0153] The electronic substrate may be a wiring substrate having wiring on a base material and at least one side of the inside of the substrate. The wiring is preferably copper wiring.

[0154] The substrate may be a substrate with an insulating film having an insulating film.

[0155] As the material of the insulating film, known insulating materials can be used, such as epoxy resin, aramid resin, crystalline polyolefin resin, amorphous polyolefin resin, fluorine-containing resin (polytetrafluoroethylene, perfluorinated polyimide, perfluorinated amorphous resin, etc.), polyimide resin, polyether sulfone resin, polyphenylene sulfide resin, polyether ether ketone resin and acrylate resin.

[0156] The insulating film may be a so-called optical transparent adhesive sheet (OCA) or a solder resist film formed using a so-called solder resist.

[0157] Furthermore, the insulating film may be an insulating film formed by an insulating film forming method described later.

[0158] 〔Process 2, Process 3〕

[0159] The manufacturing method comprises: step 2 of subjecting the coating film A formed in step 1 to light irradiation treatment; and step 3 of subjecting the coating film B obtained in step 2 to light irradiation treatment to obtain a conductive film. In addition, the manufacturing method is set so that the conditions of the light irradiation treatment performed in step 2 and the conditions of the light irradiation treatment performed in step 3 satisfy the requirements 1 and 2 described later.

[0160] (Requirement 1)

[0161] In the present manufacturing method, the wavelength WL2 with the highest intensity in the irradiation light in the light irradiation treatment of step 2 and the wavelength WL3 with the highest intensity in the irradiation light in the light irradiation treatment of step 3 satisfy requirement 1 that there is a relationship of WL2<WL3.

[0162] Here, regarding the wavelength with the highest intensity in the irradiation light (hereinafter also referred to as the "maximum intensity wavelength"), when a peak with a certain degree of width is observed in the luminescence spectrum of the irradiation light, it refers to the maximum wavelength of the peak with the highest peak intensity; when the irradiation light has a narrow spectral width such as laser light, it refers to the central wavelength of the light.

[0163] Regarding the maximum intensity wavelength WL2 in the light irradiation treatment in process 2 and the maximum intensity wavelength WL3 in the light irradiation treatment in process 3, from the viewpoint of better adhesion, volume resistivity and porosity of the manufactured conductive film, it is preferred to satisfy WL3-WL2>10nm, and it is more preferred to satisfy WL3-WL2>50nm.

[0164] The upper limit of WL3-WL2 is not particularly limited, and is, for example, 800 nm or less.

[0165] The respective values ​​of the maximum intensity wavelength WL2 and the maximum intensity wavelength WL3 can be appropriately selected from any of the ultraviolet region, the visible light region, and the infrared region so as to satisfy the above-mentioned requirement 1.

[0166] The maximum intensity wavelengths WL2 and WL3 of the irradiation light are preferably both within the wavelength range of 250 to 1500 nm.

[0167] From the viewpoint of better unevenness of the conductive film, the maximum intensity wavelength WL2 is more preferably in the range of 250 to 1000 nm, further preferably in the range of 250 to 445 nm, and particularly preferably in the range of 280 to 390 nm.

[0168] Furthermore, from the viewpoint of achieving better adhesion of the conductive film, the maximum intensity wavelength WL3 is more preferably in the range of 300 to 1500 nm, further preferably in the range of 360 to 1200 nm, and particularly preferably in the range of 380 to 1000 nm.

[0169] As the light source used in the light irradiation treatment in step 2 and step 3, a light source of ultraviolet light, visible light and infrared light with a maximum intensity wavelength within the above-mentioned range can be used, for example, LED (Light Emitting Diode), LD (Laser Diode), solid laser (such as YAG laser, etc.), gas laser, mercury lamp, metal halide lamp, and ultraviolet fluorescent lamp can be listed.

[0170] Among them, LED, LD, solid laser or gas laser is preferred from the viewpoint of narrow spectral width of irradiation light, and LED or LD is preferred from the viewpoint of small size, long life, high efficiency and low cost.

[0171] Regarding the maximum intensity wavelength of the irradiation light for the light irradiation treatment of each process, the emission spectrum of the irradiation light is measured using a spectrometer (for example, the fiber multi-channel spectrometer "USB4000" manufactured by Ocean Optics Corporation, etc.) to obtain it.

[0172] Moreover, in the case where the light source is a laser, the theoretical value corresponding to its type can be used as the maximum intensity wavelength of the irradiation light.

[0173] (Requirement 2)

[0174] In this manufacturing method, the exposure amount EA2 of the light irradiation treatment in Process 2 and the exposure amount EA3 of the light irradiation treatment in Process 3 satisfy Requirement 2 having the relationship of EA2 < EA3.

[0175] Regarding the exposure amount EA2 in the coating film A based on the light irradiation treatment of Process 2 and the exposure amount EA3 in the coating film B based on the light irradiation treatment of Process 3, from the viewpoint of more excellent adhesion, volume resistivity, film surface unevenness, and porosity of the manufactured conductive film, the ratio (EA3 / FA2) of the exposure amount EA3 to the exposure amount EA2 preferably satisfies EA3 / EA2 > 2, more preferably satisfies EA3 / FA2 > 3, and further preferably satisfies EA3 / EA2 ≥ 5.

[0176] The upper limit value of EA3 / EA2 is not particularly limited, for example, it is 20 or less, preferably 15 or less.

[0177] The respective values of the exposure amount EA2 and the exposure amount EA3 can be appropriately selected so that the ratio EA3 / EA2 is included in the above range.

[0178] From the viewpoint of more excellent film surface unevenness and volume resistivity of the conductive film, the exposure amount EA2 is preferably in the range of 0.1 to 10 J / cm 2 and more preferably in the range of 0.5 to 5 J / cm 2 of the range.

[0179] From the viewpoint of more excellent adhesion and volume resistivity of the conductive film, the exposure amount EA3 is preferably in the range of 1 to 100 J / cm 2 and more preferably in the range of 2 to 50 J / cm 2 of the range.

[0180] Moreover, the total of the exposure amount EA2 and the exposure amount EA3 is preferably in the range of 1 to 100 J / cm 2 and more preferably in the range of 2 to 50 J / cm 2 of the range.

[0181] The exposure amount in the coating film of each light irradiation treatment is measured according to the following method.

[0182] The irradiation light irradiated to the coating film from each light source is measured using an ultraviolet, visible and / or infrared measuring device, and the maximum intensity wavelength of the irradiation light is obtained from the measured luminescence spectrum. In addition, the measured luminescence spectrum is divided into the following wavelength regions, and the integrated light amount of the wavelength region where the maximum intensity wavelength of the irradiation light exists is calculated, thereby obtaining the exposure amount in the coating film based on the light irradiation treatment.

[0183] Wavelength region: UVC (250-280nm), UVB (280-320nm), UVA (320-390nm), UVV (390-445nm), visible light (445-800nm), near infrared (800-2500nm).

[0184] As the apparatus used for measuring the above-mentioned exposure amount, for example, there can be listed an ultraviolet light measuring apparatus "UVPower PUCK (registered trademark) II" (manufactured by EIT), a visible light measuring apparatus "LT665 beam profiler" (manufactured by Ophir), and an infrared measuring apparatus "LT665 beam profiler, Pyrocam III HR profiler" (manufactured by Ophir).

[0185] When using irradiation light with a narrow spectral width such as laser, the exposure amount can be obtained using an integrated light meter having a light receiving portion selected according to the maximum intensity wavelength of the irradiation light. Examples of the integrated light meter system used in this case include an ultraviolet integrated light meter "UIT-250" (manufactured by USHIO INC.), a visible light measuring device "LT665 beam profiler" (manufactured by Ophir), and an infrared measuring device "LT665 beam profiler, Pyrocam III HR profiler" (manufactured by Ophir).

[0186] The light receiving unit used for measuring the exposure amount can be selected according to the maximum intensity wavelength of the irradiated light. For example, a light receiving unit having a central wavelength of 172 nm, 254 nm, 313 nm, 365 nm, or 405 nm can be used.

[0187] The time from the time when the coating film A is formed by step 1 to the time when the light irradiation treatment of step 2 is started is preferably within 300 seconds, and more preferably within 60 seconds. By starting the light irradiation within the above time, the ink can be suppressed from diffusing from the coating film A, so that it becomes easier to form a thick film, and the adhesion and film surface unevenness of the manufactured conductive film are more excellent. The lower limit of the above time is not particularly limited, and the light irradiation treatment can be started immediately after the coating film A is formed.

[0188] In addition, the time point of forming the coating film A refers to the time point when the ink droplets of the conductive ink land on the substrate, etc., when the coating film A is formed on the substrate using an inkjet recording method. And the time point of starting the light irradiation treatment refers to the time point when the light irradiation is started. That is, in the light irradiation treatment, the light irradiation treatment of the film of the conductive ink that has landed can be started before all the ink droplets of the conductive ink land on the substrate, etc. and the formation of the coating film A is completed.

[0189] Furthermore, the present production method may include a step of drying the coating film A composed of ink droplets landed on the substrate or the like between the time when the coating film A is formed in step 1 and the start of the light irradiation treatment in step 2 .

[0190] At least a part of the metal salt and the metal complex contained in the conductive ink is reduced by subjecting the coating film A to light irradiation. That is, the coating film B after subjecting the coating film A to light irradiation contains the reduced metal.

[0191] In the coating film B obtained by the light irradiation treatment of step 2, the ratio of the content of the reduced metal to the total mass of the metal (hereinafter referred to as the "reduced metal ratio") is not particularly limited, and is preferably 5% by mass or more. Among them, from the perspective of better adhesion of the formed conductive film and the ability to further suppress the unevenness of the film surface of the conductive film, the reduced metal ratio is preferably 30% by mass or more, and more preferably 50% by mass or more. The upper limit of the reduced metal ratio is not particularly limited, but from the perspective of better volume resistivity of the conductive film, it is preferably 95% by mass or less, and more preferably 90% by mass or less.

[0192] Furthermore, the time from the time when the light irradiation treatment of the coating film A in step 2 is completed to the time when the light irradiation treatment of the coating film B in step 3 is started is preferably within 300 seconds, more preferably within 60 seconds, and further preferably within 30 seconds. By shortening the above-mentioned elapsed time, the unevenness of the film surface caused by the wetting and diffusion of the coating film can be further suppressed, and the reduction of conductivity caused by the invasion of components such as the substrate can be suppressed. The lower limit of the above-mentioned time is not particularly limited, and the light irradiation treatment of step 3 can be started immediately after the light irradiation treatment of step 2 is completed.

[0193] 〔Conductive film〕

[0194] The conductive film produced by the present production method will be described.

[0195] The conductive film produced by the present production method contains the metal constituting the metal salt or metal complex contained in the conductive ink, and has the characteristic of being excellent in adhesion (particularly, adhesion to a substrate or an insulating film).

[0196] The above-mentioned metals are the same as the metals constituting the metal salt or the metal complex contained in the conductive ink, and therefore detailed description thereof is omitted.

[0197] The metal contained in the conductive film varies depending on the composition of the conductive ink used in the present production method, but may be only one kind or may be two or more kinds.

[0198] The content of the metal contained in the conductive film is preferably 5 to 70% by mass, more preferably 7 to 50% by mass, based on the total mass of the conductive film.

[0199] Examples of components other than the metal contained in the conductive film include the metal salt and metal complex contained in the conductive ink, and components other than the solvent.

[0200] The thickness of the conductive film is not particularly limited, but from the viewpoint of better adhesion, it is preferably 10 μm or less, more preferably 8 μm or less, and further preferably 6 μm or less. The lower limit is not particularly limited, but from the viewpoint of excellent conductivity, it is preferably 0.1 μm or more, and more preferably 0.5 μm or more.

[0201] In step 1, the conductive ink is applied in such an amount that the thickness of the conductive film is preferably within the above range.

[0202] The thickness of the conductive film can be adjusted according to the composition of the conductive ink when the coating film A is formed, etc.

[0203] In addition, regarding the thickness of the conductive film, a cross-sectional image of the conductive film was obtained using a scanning electron microscope, and the lengths of 10 points at different positions corresponding to the thickness of the conductive film were measured. The lengths of the 10 points were arithmetic averaged to obtain an arithmetic mean.

[0204] [conductor]

[0205] The conductive film produced by the present production method can be stacked on a substrate and used as a conductor.

[0206] The substrate of the conductor is the same as the substrate used in step 1 of the present production method, and therefore detailed description thereof will be omitted.

[0207] The conductor may have other components besides the substrate and the conductive film. Examples of other components besides the substrate and the conductive film include an insulating film and electronic components (semiconductor devices, ground wiring, etc.) mounted on the substrate.

[0208] In particular, when used as an electromagnetic wave shield, the conductor preferably has a base material, an insulating film, and a conductive film in this order.

[0209] 〔Insulating film〕

[0210] The insulating film is a film having electrical insulating properties, and has a function of electrically insulating components disposed with the insulating film interposed therebetween.

[0211] Examples of the insulating film include an insulating film included in the above-mentioned substrate with an insulating film and an insulating film formed on a substrate using insulating ink by a method described later.

[0212] <Method for Forming Insulating Film>

[0213] As a method for forming an insulating film on a substrate, for example, there can be mentioned a method having a step of applying insulating ink on a substrate to form a coating film and a step of curing the formed coating film of the insulating ink.

[0214] The substrate for forming the insulating film is the same as the substrate used in step 1 of the present production method, and therefore a detailed description thereof will be omitted.

[0215] The method of applying the insulating ink to the substrate is not particularly limited, and examples thereof include known methods such as coating, inkjet recording, and dipping. Among them, it is preferred to apply the insulating ink using an inkjet recording method from the viewpoint that a small amount of droplets can be ejected to reduce the thickness of the conductive film.

[0216] The method for forming the coating film using the inkjet recording method, including its preferred embodiment, is the same as the method for forming the coating film A by the inkjet recording method in step 1, and therefore a detailed description thereof will be omitted.

[0217] The method of curing the insulating ink coating film formed on the substrate is not particularly limited, but a method of forming an insulating film by irradiating the insulating ink coating film with active energy rays is preferred.

[0218] The exposure amount during irradiation with active energy rays is preferably 0.1 to 100 J / cm 2 , more preferably 1 to 50 J / cm 2 In addition, when the application of the insulating ink and the irradiation of the active energy ray are regarded as one cycle, the exposure amount mentioned here means the exposure amount of the active energy ray in one cycle.

[0219] Furthermore, from the viewpoint of suppressing the generation of wrinkles in the insulating film, the illuminance during irradiation with active energy rays is preferably 8 W / cm 2 More preferably 10W / cm 2 The upper limit of the illumination is not particularly limited, for example, 20 W / cm 2 .

[0220] As the light source for active energy ray irradiation, the light sources described in the description of the light irradiation treatment in step 2 and step 3 can be mentioned.

[0221] In forming the insulating film, the treatment cycle including forming the coating film using the insulating ink and irradiating the coating film with active energy rays may be performed only once or a plurality of times.

[0222] By performing the above-mentioned treatment cycle multiple times, the thickness of the insulating film can be more easily adjusted. In addition, the thickness of the insulating film can also be adjusted by the amount and composition of the insulating ink applied to the substrate.

[0223] (Insulation ink)

[0224] The insulating ink used for forming the insulating film will be described.

[0225] Insulating ink is an ink used to form an insulating film with electrical insulation properties. Electrical insulation means that the volume resistivity is 10 10 Properties above Ωcm.

[0226] The insulating ink is preferably an active energy ray-curable ink.

[0227] Examples of the insulating ink include inks containing a polymerizable monomer and a polymerization initiator.

[0228] A polymerizable monomer refers to a monomer having at least one polymerizable group in one molecule. The polymerizable group in the polymerizable monomer may be a cation polymerizable group or a radical polymerizable group, and is preferably a radical polymerizable group, and more preferably an ethylenically unsaturated group, from the perspective of curability.

[0229] A monomer refers to a compound having a molecular weight of not more than 1000. The molecular weight can be calculated from the types and numbers of atoms constituting the compound.

[0230] The polymerizable monomer may be a monofunctional polymerizable monomer having one polymerizable group, or may be a polyfunctional polymerizable monomer having two or more polymerizable groups.

[0231] The monofunctional polymerizable monomer is not particularly limited as long as it is a monomer having one polymerizable group. From the viewpoint of curability, the monofunctional polymerizable monomer is preferably a monofunctional free radical polymerizable monomer, and more preferably a monofunctional ethylenically unsaturated monomer.

[0232] Examples of the monofunctional ethylenically unsaturated monomer include monofunctional (meth)acrylates, monofunctional (meth)acrylamides, monofunctional aromatic vinyl compounds, monofunctional vinyl ethers, and monofunctional N-vinyl compounds.

[0233] From the perspective of improving heat resistance, the monofunctional (meth)acrylate is preferably a monofunctional (meth)acrylate having an aromatic ring or an aliphatic ring, and more preferably isobornyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, or dicyclopentanyl (meth)acrylate.

[0234] The polyfunctional polymerizable monomer is not particularly limited as long as it has two or more polymerizable groups. From the perspective of curability, the polyfunctional polymerizable monomer is preferably a polyfunctional free radical polymerizable monomer, and more preferably a polyfunctional ethylenically unsaturated monomer.

[0235] Examples of the polyfunctional ethylenically unsaturated monomer include polyfunctional (meth)acrylate compounds and polyfunctional vinyl ethers.

[0236] From the viewpoint of curability, the polyfunctional polymerizable monomer is preferably a monomer having 3 to 11 carbon atoms in the part other than the (meth)acryloyl group. Among the monomers having 3 to 11 carbon atoms in the part other than the (meth)acryloyl group, 1,6-hexanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, PO-modified neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate (EO chain n=4) or 1,10-decanediol di(meth)acrylate is more preferred.

[0237] The polymerizable monomer may be used alone or in combination of two or more. The insulating ink preferably contains two or more polymerizable monomers.

[0238] The content of the polymerizable monomer is preferably 10 to 98% by mass, more preferably 50 to 98% by mass, based on the total mass of the insulating ink.

[0239] Examples of the polymerization initiator contained in the insulating ink include oxime compounds, alkylphenone compounds, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, sulfur compounds, hexaarylbisimidazole compounds, borate compounds, azinium compounds, titanocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamines.

[0240] Among them, the polymerization initiator contained in the insulating ink is preferably at least one selected from the group including oxime compounds, alkylphenone compounds and bismuth titanocene compounds, more preferably an alkylphenone compound, and further preferably at least one selected from the group including α-aminoalkylphenone compounds and benzyl ketal alkylphenone compounds.

[0241] The content of the polymerization initiator is preferably 0.5 to 20% by mass, more preferably 2 to 10% by mass, based on the total mass of the insulating ink.

[0242] The insulating ink may contain other components other than the polymerization initiator and the polymerizable monomer as optional components. Other components include chain transfer agents, polymerization inhibitors, sensitizers, surfactants, co-sensitizers, ultraviolet absorbers, antioxidants, anti-fading agents, and additives such as alkaline compounds.

[0243] The viscosity of the insulating ink is not particularly limited, and may be, for example, 0.001 to 5000 Pa·s. When the coating is formed by spraying or inkjet recording, the viscosity of the insulating ink is not particularly limited, and is preferably 0.5 to 100 mPa·s, and more preferably 2 to 60 mPa·s.

[0244] The surface tension of the insulating ink is not particularly limited, but is preferably 60 mN / m or less, more preferably 20 to 50 mN / m, and further preferably 25 to 45 mN / m.

[0245] The viscosity and surface tension of the insulating ink can be measured by a known method.

[0246] The thickness of the insulating film is preferably 30 to 3000 μm. When the thickness of the insulating film is within the above range, the conductive film can be formed more easily and the insulating property of the insulating film is further improved.

[0247] The thickness of the insulating film can be measured by the above-mentioned measuring method for the conductive film.

[0248] 〔Conductor manufacturing method〕

[0249] As a method for producing a conductor, for example, there can be mentioned a method having a step of forming a conductive film on a substrate according to the present production method.

[0250] The method for manufacturing a conductor may be a method for manufacturing a printed wiring board.

[0251] Examples of a method for producing a printed wiring board include a method comprising the step of forming a conductive film on a substrate for a printed wiring board such as an electronic substrate on which electronic components are mounted according to the present production method.

[0252] The method for producing a conductor may be a method for producing an electromagnetic wave shield including the step of forming a conductive film on a substrate according to the present production method.

[0253] The substrate used in the method for manufacturing an electromagnetic wave shield may be an electronic substrate on which the above-mentioned electronic components are mounted. In other words, the method for manufacturing a conductor may be a method for manufacturing a printed wiring board with an electromagnetic wave shield, comprising a step of forming a conductive film on an electronic substrate on which electronic components are mounted according to the manufacturing method.

[0254] When forming a conductive film on an electronic substrate on which electronic components are mounted, it is preferred to form the conductive film so as to cover the electronic components from the viewpoint of better electromagnetic wave shielding properties. Furthermore, the conductive film is preferably electrically connected to a ground electrode.

[0255] In the above-mentioned method for manufacturing a printed wiring board or an electromagnetic wave shield, it is preferred that an insulating film is formed on a substrate by the above-mentioned insulating film forming method, and then a conductive film covering the insulating film is formed by the present manufacturing method.

[0256] By providing an insulating film formed of insulating ink between the substrate and the conductive film, a printed wiring board or an electromagnetic shielding body with further improved adhesion of the conductive film can be produced. In addition, by the above method, an electromagnetic shielding body with better electromagnetic shielding properties can be produced.

[0257] When an insulating film and a conductive film are disposed on an electronic substrate on which electronic components are mounted, it is preferred to dispose the insulating film so as to cover all the electronic components except the ground electrode in order to achieve better electromagnetic wave shielding properties.

[0258] [use]

[0259] The conductive film produced by the present production method and the conductor having the substrate and the conductive film produced by the present production method can be used in various applications.

[0260] As a conductor, for example, an electromagnetic wave shield can be cited. The electromagnetic wave shield blocks electromagnetic waves such as radio waves and microwaves (ultra-short waves) generated by electronic devices, thereby suppressing the influence of interference from external electromagnetic waves on semiconductor devices and the influence of electromagnetic waves radiated from semiconductor devices on other semiconductor devices or electronic devices. In addition, the electromagnetic wave shield can prevent the generation of static electricity.

[0261] When a conductor is used as an electromagnetic wave shield, the conductive film is often electrically connected to a ground wiring provided on a substrate, etc. At least a portion of the conductive film is electrically connected to the ground wiring, whereby a current generated by an electromagnetic wave incident on the conductive film flows into the ground wiring, and the electromagnetic wave is attenuated. The current generated in the conductive film becomes easy to flow into the ground wiring, and the electromagnetic wave becomes easy to attenuate, so it is preferred that there are more areas where the conductive film and the ground wiring are electrically connected.

[0262] Such an electromagnetic wave shield can be used in electronic devices such as personal computers, workstations, imaging equipment, and electronic medical equipment.

[0263] Example

[0264] Hereinafter, the present invention will be further described in detail by giving examples. The materials, usage amounts, ratios, processing contents and processing sequences shown in the following examples can be appropriately changed without departing from the purpose of the present invention. Therefore, the present invention is not limited to the modes shown in the following examples. In addition, "parts" and "%" are weight references unless otherwise specified.

[0265] [Example 1]

[0266] <Preparation of Conductive Ink 1>

[0267] 570.0 g of silver neodecanoate was added to a 2000 mL three-necked flask. Then, 400.0 g of trimethylbenzene and 30.0 g of terpineol were added and the obtained mixture was stirred to obtain a solution containing a silver salt. The solution was filtered using a PTFE (polytetrafluoroethylene) membrane filter with a pore size of 0.45 μm to obtain a conductive ink 1.

[0268] As a result of measurement using an ultraviolet-visible-infrared spectrophotometer ("V700" manufactured by JASCO CORPORATION), the absorbance of the conductive ink 1 at a wavelength of 350 to 450 nm at an optical path length of 10 mm was 0.05.

[0269] <Process 1>

[0270] The conductive ink 1 was filled into an ink cartridge of an inkjet recording device (product name "Samba G3L", manufactured by FUJIFILM DIMATIX). The image recording conditions of the inkjet recording device were set to 1200 dpi (dots per inch) for resolution and 5 pL for droplet ejection per dot.

[0271] The solder resist substrate was fixed on the stage of the inkjet recording device and heated to 70°C. Then, the conductive ink 1 was ejected onto the surface of the solder resist film under the above-mentioned image recording conditions to form a coating film A1 consisting of a solid image with a size of 3 mm in width and 50 mm in length. The thickness of the formed coating film A1 was 40 μm.

[0272] <Process 2>

[0273] The ultraviolet irradiator (light source: LED, maximum intensity wavelength (WL2) 313 nm, peak intensity 100 mW / cm2) pre-installed in the above-mentioned inkjet recording device was used. 2, irradiation area 2cm×8cm), the coating A1 formed by process 1 was subjected to light irradiation treatment. The light irradiation treatment of process 2 was started 5 seconds after the end of process 1. In the light irradiation treatment of process 2, the irradiation amount was adjusted so that the exposure amount EA2 in the coating A1 formed by process 1 became the amount described in Table 1 described later.

[0274] (Determination of Reducing Metal Ratio)

[0275] The reduced metal ratio (the ratio of the content of the reduced metal to the total mass of the metal) (mass %) in the coating film B1 subjected to the light irradiation treatment in step 2 was measured by the following method.

[0276] The glass substrate is fixed on the carrier of the inkjet recording device. Then, the conductive ink 1 is ejected onto the surface of the glass substrate under the same image recording conditions as in the above-mentioned process 1, forming a coating A1 consisting of a solid image with a size of 100 mm in width and 100 mm in length. The formed coating was subjected to light irradiation treatment under the same conditions as in process 2. The irradiated coating was scraped off with a metal scraper, and the sample of the obtained coating was diluted with 30 mL of trimethylbenzene. Using a centrifuge ("himac CS-150FNX" manufactured by Koki Holdings Co., Ltd.), the test liquid containing the sample of the obtained coating was centrifuged at 30000g for 180 minutes. The unit "g" represents the relative centrifugal acceleration relative to the standard gravitational acceleration. The supernatant was removed from the test liquid treated by centrifugation, and after the residue was washed with tetrahydrofuran, it was dried under reduced pressure. The weight of the obtained sample was measured, and based on the measured weight, the reduced metal ratio (mass %) of the coating film subjected to the light irradiation treatment in step 2 was calculated by the following formula.

[0277] Reducing metal ratio = (measured weight of the sample) / {(coating amount of conductive ink 1) × (content (concentration) of metal salt and metal complex contained in conductive ink 1)} × 100

[0278] <Process 3>

[0279] Using an infrared laser irradiation device (manufactured by Hamamatsu Photonics Co., Ltd., with a maximum intensity wavelength (WL3) of 940 nm) pre-installed in the above-mentioned inkjet recording device, the entire surface of the coating film B1 processed by step 2 was subjected to light irradiation treatment to form a conductive film. The light irradiation treatment of step 3 was started 5 seconds after the light irradiation treatment of step 2 was completed. In addition, in the light irradiation treatment of step 3, the irradiation amount was adjusted so that the exposure amount EA3 in the coating film B1 processed by step 2 became the amount described in Table 1 described later.

[0280] The thickness of the conductive film produced in Example 1 was 0.3 μm.

[0281] [Example 2 to Example 10, Comparative Example 1 to Comparative Example 2]

[0282] A conductive film was formed according to the method described in Example 1, except that at least one of the light source of the irradiation light in steps 2 and 3, the exposure amount in the coating film, and the time elapsed after the light irradiation treatment in step 2 is completed to the start of the light irradiation treatment in step 3 is changed to the conditions described in Table 1 described later.

[0283] As the light source of the light irradiation device, an LED with a maximum intensity wavelength of 280 nm was used in step 1 of Example 2, Example 9, and Comparative Example 2, an LED with a maximum intensity wavelength of 365 nm was used in step 1 of Example 3 and Example 10, and step 2 of Example 9, an LED with a maximum intensity wavelength of 385 nm was used in step 2 of Example 10, and an LED with a maximum intensity wavelength of 405 nm was used in step 1 of Comparative Example 1. In step 2 of Comparative Example 1, a YAG laser with a maximum intensity wavelength of 353 nm was used as the light source of the light irradiation device.

[0284] The exposure amount in the coating film of each light irradiation treatment was measured by the above method using an ultraviolet light measuring device ("UV PowerPUCK (registered trademark) II", manufactured by EIT) and an infrared light measuring device "LT665 beam profiler, Pyrocam III HRprofiler" (manufactured by Ophir).

[0285] The thickness of the conductive films produced in Examples 2 to 10 and Comparative Examples 1 and 2 was 0.3 μm.

[0286] [Example 11]

[0287] <Preparation of Conductive Ink 2>

[0288] 25.1 g of 1-propanol, 20 g of silver acetate and 5 g of formic acid were added to a three-necked flask with a capacity of 300 mL, and the obtained mixture was stirred for 20 minutes. The precipitate of the generated silver salt was decanted three times using 1-propanol and washed. 14.4 g of 1-propylamine and 25.1 g of 1-propanol were added to the precipitate, and the obtained mixture was stirred for 30 minutes. Then, 10 g of water was added to the mixture, and further stirred to obtain a solution containing a silver complex. The solution was filtered using a membrane filter made of PTFE (polytetrafluoroethylene) with a pore size of 0.45 μm to obtain conductive ink 2.

[0289] As a result of measurement using an ultraviolet-visible-infrared spectrophotometer ("V700" manufactured by JASCO CORPORATION), the absorbance of the conductive ink 2 at a wavelength of 350 to 450 nm at an optical path length of 10 mm was 0.1.

[0290] A conductive film was formed by the same method as in <Step 1>, <Step 2>, and <Step 3> of Example 1, except that the conductive ink 2 was used instead of the conductive ink 1.

[0291] The thickness of the conductive film produced in Example 11 was 0.3 μm.

[0292] [Example 12]

[0293] <Preparation of Insulating Protective Layer Forming Ink A1>

[0294] The components of the following composition were mixed, and the mixture was stirred at 25° C. and 5000 rpm for 20 minutes using a mixer (product name “L4R”, manufactured by Silverson Nippon Limited) to obtain an insulating protective layer-forming ink A1.

[0295] - Composition of Insulating Protective Layer Forming Ink A1 -

[0296] · Omni.379: 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)-butan-1-one (product name "Omnirad 379", manufactured by IGM Resins BV) ... 1.0 mass%

[0297] ·4-PBZ: 4-phenylbenzophenone (product name "Omnirad 4-PBZ", manufactured by IGM) ... 7.5 mass%

[0298] ·NVC: N-vinyl caprolactam (manufactured by FUJIFILM Wako Pure Chemical Corporation) ... 15.0 mass%

[0299] · HDDA: 1,6-hexanediol diacrylate (product name "SR238" manufactured by Sartomer) ... 25.5% by mass

[0300] IBOA: Isobornyl acrylate (product name "SR506", manufactured by Sartomer) ... 30.0 mass%

[0301] Pentaerythritol tetrakis(3-mercaptobutyrate) (product name "Karenz MT-PE1") ... 20.0 mass%

[0302] ·MEHQ: p-Methoxyphenol (manufactured by FUJIFILM Wako Pure Chemical Corporation) ... 1.0 mass%

[0303] <Insulating Protective Layer Formation Step>

[0304] The ink A1 was filled in an ink cartridge of an inkjet recording device (product name "Samba G3L", manufactured by FUJIFILM DIMATIX). The image recording conditions of the inkjet recording device were set to 1200 dpi (dots per inch) in resolution and 5 pL in droplet ejection volume per dot.

[0305] The solder resist substrate was fixed on the stage of the inkjet recording device. Then, the ink A1 was ejected onto the surface of the solder resist film under the above-mentioned image recording conditions to form a coating film. The formed coating film was irradiated with UV (ultraviolet light) with a wavelength of 365nm, thereby curing the coating film to form an insulating protective layer consisting of a solid image with a size of 10mm in width and 80mm in length. The thickness of the formed insulating protective layer was 40μm.

[0306] A conductive film was formed by the same method as in <Step 1>, <Step 2>, and <Step 3> of Example 1, except that the substrate with the insulating protective layer was used instead of the solder resist substrate and the conductive ink 1 was discharged onto the surface of the insulating protective layer to form a coating film A1.

[0307] The thickness of the conductive film produced in Example 12 was 0.3 μm.

[0308] [evaluate]

[0309] <Adhesion>

[0310] In step 1, except that a coating film A consisting of a solid image with a size of 5 cm in width and 5 cm in length was formed, conductive film samples for adhesion evaluation were prepared according to the methods described in each of the Examples and Comparative Examples.

[0311] For each sample produced, a cross-hatch test was performed by the following method. Six cuts were made on the surface of the conductive film in mutually orthogonal directions. After a piece of transparent tape ("Cellotape (registered trademark) CT-18", manufactured by Nichiban Co. Ltd.) was attached to the conductive film with the cuts, the tape piece was peeled off from the conductive film. The peeling of the conductive film on the surface from which the tape piece was peeled (exposure of the lower layer) and the amount of the conductive film attached to the peeled tape piece were visually observed, and the adhesion of the conductive film to the substrate was evaluated based on the observation results according to the following evaluation criteria.

[0312] (Adhesion Evaluation Criteria)

[0313] 5: No peeling was observed on the surface of the conductive film, and no black or silver attachment was observed on the tape piece.

[0314] 4: Peeling of the conductive film was slightly observed only at the intersections of the cuts on the conductive film surface, and / or black or silver deposits were slightly observed on the tape piece.

[0315] 3: The conductive film was slightly peeled off only at the intersections of the cuts on the conductive film surface, and black or silver deposits were observed on the tape sheet over an area less than 10% of the area of ​​the cross-hatched cuts.

[0316] 2: On the surface of the conductive film, peeling of the conductive film is observed over an area less than 10% of the area of ​​the portion cut by the cross-hatch pattern, and / or black or silver attached matter is observed on the tape sheet over an area greater than 10% and less than 50% of the area of ​​the portion cut by the cross-hatch pattern.

[0317] 1: On the surface of the conductive film, peeling of the conductive film is observed over an area of ​​10% or more relative to the area of ​​the portion cut by the cross-hatch pattern, and / or black or silver deposits are observed on the tape sheet over an area of ​​50% or more relative to the area of ​​the portion cut by the cross-hatch pattern.

[0318] <Volume Resistivity>

[0319] The resistance of each conductive film produced was measured at room temperature (23°C) using a resistance meter (product name "DT4222", manufactured by HIOKI EE CORPORATION). In addition, the cross-sectional area of ​​each conductive film was measured at room temperature (23°C) using a scanning electron microscope (product name "S-4700", manufactured by HITACHI). The volume resistivity (μΩ·cm) was calculated from the measured resistance value and cross-sectional area, and the obtained volume resistivity was evaluated according to the following evaluation criteria. The lower the volume resistivity, the better the conductivity of the conductive film.

[0320] (Volume resistivity evaluation standard)

[0321] 5: Volume resistivity is 8 μΩ·cm or less.

[0322] 4: Volume resistivity is more than 8 μΩ·cm and less than or equal to 10 μΩ·cm.

[0323] 3: Volume resistivity is more than 10 μΩ·cm and less than 12 μΩ·cm.

[0324] 2: Volume resistivity is more than 12 μΩ·cm and less than 15 μΩ·cm.

[0325] 1: Volume resistivity exceeds 15 μΩ·cm.

[0326] <Uneven film surface>

[0327] In step 1, except that a coating film A consisting of a solid image having a size of 4 cm in width and 16 cm in length was formed, conductive film samples for evaluating film surface unevenness were prepared according to the methods described in the examples and comparative examples.

[0328] The surface of each sample was cut at 1 cm intervals in mutually orthogonal directions to form 64 1 cm × 1 cm square areas. The surface resistance (Ω / sq.) of each area was measured using a 4-terminal 4-probe resistivity meter ("Loresta GP MCPT610", manufactured by Nittoseiko Analytech Co., Ltd.) equipped with a PSP probe. The standard deviation was calculated from the measured values ​​at 64 points, and the film surface unevenness of the conductive film was evaluated based on the calculated standard deviation according to the following evaluation criteria.

[0329] (Evaluation criteria for uneven membrane surface)

[0330] 5: The standard deviation is less than 3.

[0331] 4: The standard deviation is 3 or more and less than 5.

[0332] 3: The standard deviation is 5 or more and less than 10.

[0333] 2: The standard deviation is 10 or more and less than 20.

[0334] 1: The standard deviation is 20 or more.

[0335] <Porosity>

[0336] Each of the produced conductive films was cut in the thickness direction using a microtome (product name "RM2255", manufactured by Leica) to obtain a cross section, and the cross section was observed using a scanning electron microscope (product name "S-4700", manufactured by HITACHI LTD.) to obtain a cross section observation photograph.

[0337] The obtained cross-sectional observation photograph was processed using image software (manufactured by Adobe Systems, Inc., "Adobe Photoshop (registered trademark)"), and the critical value was adjusted to binarize the cross-sectional area of ​​the conductive film into a white area where the conductive material (metal) existed and a black area where the void existed. The ratio of the area of ​​the black area to the total area of ​​the white area and the black area (i.e., the cross-sectional area of ​​the conductive film) was calculated and used as the porosity (%).

[0338] The calculated porosity (%) was evaluated according to the following evaluation criteria: The smaller the porosity, the more excellent the conductivity of the conductive film.

[0339] (Porosity Evaluation Standard)

[0340] 5: Porosity is 10% or less.

[0341] 4: Porosity is more than 10% and less than 12%.

[0342] 3: Porosity is more than 12% and less than 15%.

[0343] 2: Porosity is more than 15% and less than 20%.

[0344] 1: Porosity exceeds 20%.

[0345] Table 1 shows the production conditions and evaluation results of the conductive films in each example and each comparative example.

[0346] In the table, the column “Light Source” shows the light source of the light irradiation device used for irradiation of each coating film, “LED” means light emitting diode, “LD” means laser diode, and “YAG” means YAG laser.

[0347] In the table, the columns of "Step 2" and "Step 3" respectively show the processing conditions of Step 2 and Step 3.

[0348] The numerical value in the column “Step Interval (Seconds)” indicates the elapsed time from the end of the light irradiation treatment in step 2 to the start of the light irradiation treatment in step 3 .

[0349] "EA2(J / cm 2 )" column and "EA3(J / cm 2 The numerical values ​​in the ")" column represent the exposure amount in the coating film A by the light irradiation treatment in step 2 and the exposure amount in the coating film B by the light irradiation treatment in step 3, respectively.

[0350] The numerical values ​​in the “WL2 (nm)” column and the “WL3 (nm)” column represent the maximum intensity wavelength of the irradiation light applied to the coating A in step 2 and the maximum intensity wavelength of the irradiation light applied to the coating B in step 3, respectively.

[0351] The numerical value in the column “ΔWL (nm)” indicates the difference ( WL3 − WL2 ) obtained by subtracting the maximum intensity wavelength WL2 of the irradiation light in step 2 from the maximum intensity wavelength WL3 of the irradiation light in step 3 .

[0352] The numerical value in the column “EA3 / EA2” indicates the ratio of the exposure amount EA3 in the coating film B in step 3 to the exposure amount EA2 in the coating film A in step 2.

[0353]

[0354] For the conductive film produced by the method described in Example 12, the adhesion, volume resistivity, film surface unevenness, and porosity were evaluated in the same manner as above, and the same evaluation results as in Example 1 were obtained.

[0355] As described above, it was confirmed that the manufacturing method of the present invention has more excellent adhesion than the manufacturing method of Comparative Example 1 that does not satisfy WL2 < WL3 and the manufacturing method of Comparative Example 2 that does not satisfy EA2 < EA3.

[0356] It was confirmed that when EA3 / FA2 exceeds 3, the adhesion, volume resistivity, film surface unevenness, and porosity are more excellent (comparison between Example 3 and Example 4).

[0357] It was confirmed that in the coated film B subjected to the light irradiation treatment of Step 2, when the ratio of the content of the reduced metal to the total mass of the metal is 50% by mass or more, the adhesion and film surface unevenness are more excellent (comparison between Example 4 and Example 5).

[0358] It was confirmed that when the elapsed time from the end of the light irradiation treatment of Step 2 to the start of the light irradiation treatment of Step 3 is within 60 seconds, the adhesion and film surface unevenness are more excellent (comparison between Example 6 and Example 7).

[0359] It was confirmed that when EA3 / FA2 exceeds 3, the adhesion, volume resistivity, film surface unevenness, and porosity are more excellent (comparison between Example 3 and Example 4).

[0360] It was confirmed that when the maximum intensity wavelength WL2 of the irradiation light in Step 2 and the maximum intensity wavelength WL3 of the irradiation light in Step 3 satisfy WL3 - WL2 > 50 nm, the adhesion, volume resistivity, and porosity are more excellent (comparison between Example 3, Example 9, and Example 10).

Claims

1. A method for manufacturing a conductive film, comprising: Step 1, applying ink containing at least one of a metal salt and a metal complex to form a coating film; Step 2, subjecting the coating film to light irradiation treatment; and Step 3, subjecting the coating film obtained in step 2 to light irradiation treatment to obtain a conductive film, The wavelength WL2 with the largest intensity in the irradiation light of the light irradiation treatment in the step 2 and the wavelength WL3 with the largest intensity in the irradiation light of the light irradiation treatment in the step 3 satisfy WL2<WL3, Furthermore, the exposure amount EA2 of the light irradiation treatment in the step 2 and the exposure amount EA3 of the light irradiation treatment in the step 3 satisfy EA2<EA3.

2. The method for producing a conductive film according to claim 1, wherein: The exposure amount EA2 of the light irradiation treatment in the step 2 and the exposure amount EA3 of the light irradiation treatment in the step 3 satisfy EA3 / EA2>3.

3. The method for producing a conductive film according to claim 1 or 2, wherein: In the coating film obtained in the step 2, the content of the reduced metal is 50% by mass or more relative to the total mass of the metal.

4. The method for producing a conductive film according to claim 1 or 2, wherein: In the step 1, the ink is applied in such an amount that the thickness of the conductive film becomes 2 μm or less.

5. The method for producing a conductive film according to claim 1 or 2, wherein: The elapsed time from the completion of the light irradiation treatment in the step 2 to the start of the light irradiation treatment in the step 3 is within 60 seconds.

6. The method for producing a conductive film according to claim 1 or 2, wherein: The wavelength WL2 and the wavelength WL3 satisfy WL3-WL2>50nm.

7. The method for producing a conductive film according to claim 1 or 2, wherein: The ink contains at least one of a silver salt and a silver complex.

8. A method for producing an electromagnetic shield, comprising the step of forming a conductive film on a substrate according to the method for producing a conductive film according to claim 1 or 2.

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