Conductive inks and printed materials

Abstract

To provide a conductive ink that contributes to reducing environmental impact and can form a conductive layer with excellent conductivity. [Solution] The conductive ink of the present invention is a conductive ink for flexographic printing, offset printing, or screen printing, and is curable by active energy rays. The conductive ink of the present invention comprises conductive particles and a binder component. The binder component comprises a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranch structure. The content of the polyfunctional polymerizable compound is 1 part by mass or more per 100 parts by mass of the total amount of conductive particles.

Description

[Technical Field]

[0001] This invention relates to conductive inks and printed materials. [Background technology]

[0002] Conventionally, conductive layers used in electromagnetic shielding for PDP displays, conductive circuits in printed circuit boards, and antenna circuits for RFID (Radio Frequency Identification) were formed by etching. However, etching requires a photolithograph and the disposal of waste liquids such as etching solutions, resulting in high manufacturing costs and a significant environmental impact. Therefore, there has been a need for a method to form conductive layers without using etching.

[0003] Methods for forming a conductive layer without using etching include dry methods such as vacuum deposition of metal, chemical deposition, and ion sputtering; sintering methods that form a conductive layer by printing and sintering using a conductive paste containing nano-sized conductive metals; and printing methods that form a conductive layer by printing using conductive ink containing conductive metals and evaporating the solvent. However, the above dry methods cannot ensure sufficient thickness of the conductive layer, resulting in insufficient conductivity. Furthermore, while the above sintering methods can form a thicker conductive layer than the dry methods, the conductivity is insufficient to meet the requirements of a conductive circuit.

[0004] One known printing method involves using a solvent-curing conductive ink containing metal particles, resin varnish, and a solvent (see Patent Document 1). However, solvent-curing conductive inks have the problem of solvent evaporation during drying. Another known printing method involves using a conductive ink mainly containing water, as well as metal ultrafine particles, polymer latex, and polyoxyalkylene alkylamine, to transfer an ink coating formed on a silicone resin surface to a printing substrate (see Patent Document 2). However, conductive inks using water as a medium require drying, which takes time. Therefore, there is a need for a method that uses an active energy ray curing type conductive ink, such as ultraviolet light, which can be cured in a short time and reduce environmental impact.

[0005] As an example of the above-mentioned active energy ray-curable conductive ink, an active energy ray-curable conductive ink is known that comprises a conductive substance, a (meth)acrylate compound having a vinyl ether group as a binder component, and an active energy ray polymerizable compound (see Patent Document 3). Patent Document 3 also describes that the ink exhibits good printability and low resistance values ​​of the printed conductive circuit when used in flexographic printing. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2010-047649 [Patent Document 2] Japanese Patent Publication No. 2012-188558 [Patent Document 3] Japanese Patent Publication No. 2008-189758 [Overview of the project] [Problems that the invention aims to solve]

[0007] Furthermore, to form a conductive layer with superior conductivity, the thickness of the conductive layer needs to be increased. On the other hand, when an active energy ray-curable conductive ink is applied thickly, the conductive ink tends to cure insufficiently in high-speed printing methods such as flexographic printing and offset printing. Insufficient curing results in inadequate conductivity.

[0008] The present invention aims to solve these problems, and its objective is to provide a conductive ink that contributes to reducing environmental impact and can form a conductive layer with excellent conductivity. [Means for solving the problem]

[0009] The present invention comprises conductive particles and a binder component. The above binder component comprises a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranched structure. The content of the above polyfunctional polymerizable compound is 1 part by mass or more per 100 parts by mass of the total amount of the above conductive particles. We provide an active energy ray-curable conductive ink for flexographic printing, offset printing, or screen printing.

[0010] The above polyfunctional polymerizable compound preferably has 6 to 30 polymerizable functional groups.

[0011] The above polyfunctional polymerizable compounds preferably have a (meth)acryloyl group as a polymerizable functional group.

[0012] The above polyfunctional polymerizable compound is preferably a polyester (meth)acrylate compound.

[0013] The content of the above-mentioned polyfunctional polymerizable compound is preferably 3 to 20% by mass relative to the total amount of the above-mentioned active energy ray curable conductive ink.

[0014] The content ratio of the conductive particles is preferably 60 to 90% by mass relative to the total amount of the active energy ray-curable conductive ink.

[0015] The content ratio of the above polyfunctional polymerizable compound is preferably 5% by mass or more based on 100% by mass of the total amount of the above binder component.

[0016] The above active energy ray-curable conductive ink preferably contains an ink acylphosphine oxide photoinitiator, a photoactive oxime photoinitiator, and a quinone photoinitiator.

[0017] The above active energy ray-curable conductive ink preferably contains a phosphate ester-based dispersant.

[0018] The above active energy ray-curable conductive ink is for offset printing, and it is preferable that the above binder component further contains epoxy (meth) acrylate.

[0019] The above active energy ray-curable conductivity is preferably for waterless offset printing.

[0020] In addition, the present invention provides a printed matter including a base material and a conductive printing layer provided on at least one surface of the above base material. The above conductive printing layer contains conductive particles and a binder component. The above binder component contains a crosslinked structure derived from a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranched structure, and provides a printed matter.

[0021] In addition, the present invention provides a communication device including the above printed matter.

[0022] In addition, the present invention provides an antenna including the above printed matter.

Effects of the Invention

[0023] The conductive ink of the present invention contributes to reducing environmental impact and makes it possible to form a conductive layer with excellent conductivity. Therefore, the conductive ink of the present invention makes it possible to form a conductive layer with excellent conductivity using high-speed printing methods such as flexographic printing, offset printing, and screen printing, while contributing to reducing environmental impact. [Modes for carrying out the invention]

[0024] [Conductive ink] The conductive ink of the present invention comprises at least conductive particles and a binder component. The conductive ink of the present invention may also contain other components in addition to the above components.

[0025] The above-mentioned conductive ink is an active energy ray curing type ink, and is a composition that can form a conductive layer by polymerizing and hardening the polymerizable compounds (such as the polyfunctional polymerizable compounds described later) contained in the binder component upon irradiation with active energy rays.

[0026] Examples of the active energy rays mentioned above include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, as well as ultraviolet rays, with ultraviolet rays being particularly preferred. In other words, the active energy ray-curable conductive ink is preferably an ultraviolet-curable conductive ink.

[0027] (Conductive particles) The conductive layer formed by the conductive ink containing the conductive particles has conductivity. From the viewpoint of forming a conductive layer with excellent conductivity, metal particles are preferred as the conductive particles. Only one type of conductive particle may be used, or two or more types may be used.

[0028] Examples of metals that make up the above metal particles include gold, silver, copper, nickel, zinc, tin, bismuth, and indium. Only one of these metals may be used, or two or more may be used.

[0029] Examples of the above-mentioned metal particles include, specifically, copper particles, silver particles, nickel particles, silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, gold-coated nickel particles, silver-coated alloy particles, tin-coated copper particles, tin-coated nickel particles, and solder particles. Among these metal particles, silver-coated copper particles and silver particles are preferred from the viewpoint of forming a conductive layer with excellent conductivity.

[0030] Examples of the shapes of the conductive particles include spherical (perfectly spherical, ellipsoidal, potato-shaped, etc.), flake-shaped (scale-like), dendritic, fibrous, and amorphous (polyhedral). Among these, spherical and flake-shaped particles are preferred from the viewpoint of superior conductivity of the conductive layer, and flake-shaped particles are more preferred. Specifically, the conductive particles are preferably spherical silver particles, flake-shaped silver particles, spherical silver-coated copper particles, and flake-shaped silver-coated copper.

[0031] The median diameter (D50) of the conductive particles is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to 8 μm. When D50 is within the above range, the packing of conductive particles in the conductive layer is high, and the conductivity of the conductive layer is superior. D50 refers to the particle size at 50% of the integrated value in the particle size distribution determined by laser diffraction-scattering method.

[0032] Among the conductive particles described above, it is preferable to use flake-shaped metal particles with relatively different D50 values. Flake-shaped metal particles with a relatively large D50 may be referred to as "metal particles (A)," and flake-shaped metal particles with a relatively small D50 may be referred to as "metal particles (B)." Including metal particles (A) and metal particles (B) improves the packing of the conductive particles, resulting in better conductivity of the conductive layer.

[0033] The content ratio of metal particles (A) and metal particles (B) in the total amount (100% by mass) of the conductive particles is preferably 50% by mass or more, more preferably 55% by mass or more, and may be 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more. When the above content ratio is 50% by mass or more, the conductivity of the conductive layer is better. The above content ratio may be, for example, 99% by mass or less, and may be 95% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, 75% by mass or less, 70% by mass or less, or 65% by mass or less.

[0034] The mass ratio of metal particles (A) and metal particles (B) [metal particle (A) / metal particle (B)] is preferably 1 / 99 to 99 / 1, more preferably 10 / 90 to 97 / 3, and may also be 40 / 60 to 95 / 5 or 60 / 40 to 95 / 5.

[0035] The content of the conductive particles in the conductive ink is preferably 50% by mass or more, more preferably 55% by mass or more, and may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 85% by mass or more, based on the total amount of conductive ink (100% by mass). When the content is 50% by mass or more, the conductivity of the conductive layer is better. In addition, the viscosity of the conductive ink increases, making it easier to coat the conductive ink so that the thickness of the conductive layer increases.

[0036] (Binder component) The above binder component comprises at least a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranch structure. The inclusion of the polyfunctional compound in the binder component allows for rapid curing by active energy rays, sufficient curing even at high thicknesses, and the formation of a conductive layer with excellent conductivity. The above binder component may be used alone or in combination of two or more types.

[0037] The above-mentioned polyfunctional polymerizable compound is a compound having a multibranched structure which is a dendrimer structure and / or a hyperbranched structure, and examples include those with a regular multibranched structure, those with an irregular multibranched structure, those with a tree-like branching structure, and those with a radial structure. Furthermore, the above-mentioned polyfunctional polymerizable compound may be either an oligomer or a polymer. The above-mentioned polyfunctional polymerizable compound may be used alone or two or more types.

[0038] Examples of polymerizable functional groups in the above-mentioned polyfunctional polymerizable compound include functional groups that can be polymerized by active energy rays, such as radiation radical polymerizable groups such as ethylenically unsaturated groups containing carbon-carbon unsaturated bonds, and radiation cationic polymerizable groups. Examples of groups containing carbon-carbon unsaturated bonds include vinyl groups, propenyl groups, isopropenyl groups, and (meth)acryloyl groups. Examples of radiation cationic polymerizable groups include epoxy groups, oxetanyl groups, and oxolanyl groups. Among these, groups containing carbon-carbon unsaturated bonds are preferred, and (meth)acryloyl groups are more preferred. In other words, the above-mentioned polyfunctional polymerizable compound is preferably a polyfunctional (meth)acrylate compound. The above-mentioned polymerizable functional group may be one or more types.

[0039] In this specification, "(meth)acryloyl" means "acryloyl" and / or "methacryloyl" (either one or both of "acryloyl" and "methacryloyl"), and the same applies to other terms.

[0040] The number of polymerizable functional groups in the above polyfunctional compound is preferably 6 to 30, more preferably 8 to 24, and even more preferably 10 to 20.

[0041] The above polyfunctional polymerizable compound is preferably a polyester (meth)acrylate compound. The above polyester (meth)acrylate compound is a compound having multiple ester bonds, and it is preferable that the ester portion in the (meth)acrylic acid ester structure is polyester. The above polyester (meth)acrylate compound can be obtained, for example, by reacting a highly branched polyester having functional groups at the molecular ends obtained by reacting a polyhydric alcohol with a polybasic acid or its anhydride, or a highly branched polyester having functional groups at the molecular ends obtained by ring-opening polymerization of a cyclic lactone, with (meth)acrylic acid, or by synthesizing a highly branched polyester consisting of a polyfunctional carboxylic acid ester such as a trifunctional or more sorbitanic acid ester and a polyfunctional (meth)acrylic acid ester by a Diels-Alder reaction.

[0042] The viscosity of the above polyfunctional polymerizable compound at 25°C is preferably 150 to 1000 mPa·s, more preferably 200 to 700 mPa·s, and even more preferably 250 to 500 mPa·s. When the viscosity is 150 mPa·s or higher, the viscosity of the conductive ink can be moderately increased, making it easier to maintain the thickness until curing even when the conductive ink is applied thickly, and making it easier to form a thick conductive layer. When the viscosity is 1000 mPa·s or lower, the viscosity of the conductive ink can be moderately low, resulting in good printability.

[0043] The mass-average molecular weight of the above polyfunctional polymerizable compound is preferably 1000 to 3000. A mass-average molecular weight of 1000 or more allows for a moderately high viscosity of the conductive ink, making it easier to maintain thickness until curing even when the conductive ink is applied thickly, and facilitating the formation of a thick conductive layer. A mass-average molecular weight of 3000 or less allows for a moderately low viscosity of the conductive ink, resulting in good printability. The mass-average molecular weight can be measured using gel permeation chromatography (GPC).

[0044] Commercially available polyfunctional polymerizable compounds can also be used. Examples of commercially available polyfunctional polymerizable compounds include Sartomer's product "CN2302" (average number of functional groups: 16).

[0045] The content of the polyfunctional polymerizable compound is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and may be 10 parts by mass or more, or 15 parts by mass or more, per 100 parts by mass of the total amount of conductive particles. When the content is 1 part by mass or more, the conductive ink hardens more quickly by irradiation with active energy rays, and a sufficiently hardened conductive layer can be easily formed even if it is thick. The content is preferably 30 parts by mass or less, and may be 25 parts by mass or less, 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less.

[0046] The content of the polyfunctional polymerizable compound is preferably 1% by mass or more, and may be 3% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total amount (100% by mass) of the conductive ink. When the content is 3% by mass or more, the conductive ink hardens more quickly by irradiation with active energy rays, and a sufficiently hardened conductive layer can be easily formed even if it is thick. The content is preferably 20% by mass or less, and may be 15% by mass or less, or 10% by mass or less.

[0047] The above-mentioned binder components include additives such as the above-mentioned polyfunctional polymerizable compound, other polymerizable compounds other than the above-mentioned polyfunctional polymerizable compound, non-polymerizable binder oligomers or polymers, photopolymerization initiators, polymerization inhibitors, plasticizers, lubricants, dispersants, leveling agents, defoamers, antioxidants, sulfurization inhibitors, sensitizers, silane coupling agents, and thixotropic agents, and refer to substances other than conductive particles and volatile organic solvents contained in the conductive ink. The conductive ink of the present invention may further contain these binder components other than the above-mentioned polyfunctional polymerizable compound.

[0048] The content of the polyfunctional polymerizable compound in the binder component is preferably 5% by mass or more, relative to the total amount of the binder component (100% by mass), and may be 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 55% by mass or more, or 60% by mass or more. When the content is 5% by mass or more, the conductive ink hardens more quickly by irradiation with active energy rays, and a sufficiently hardened conductive layer can be easily formed even if it is thick. The content may be 100% by mass, or it may be 95% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less.

[0049] Other polymerizable compounds include compounds having only one polymerizable functional group (monofunctional monomers) and other polyfunctional polymerizable compounds other than the polyfunctional polymerizable compounds mentioned above. Other polymerizable compounds include radical polymerizable monomers such as (meth)acrylic acid esters, radical polymerizable oligomers, and radical polymerizable polymers.

[0050] Examples of the above-mentioned radical polymerizable monomers include (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include alkyl (meth)acrylic acid esters and (meth)acrylic acid esters having substituents on the alkyl group. Examples of the above substituents include polar groups such as hydroxyl groups, carboxyl groups, and halogen atoms.

[0051] Examples of (meth)acrylic acid esters having the above-mentioned hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, glycerol mono(meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid.

[0052] Examples of (meth)acrylic acid esters having the carboxyl group mentioned above include (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxyethyl maleic acid, 2-(meth)acryloyloxypropyl succinic acid, 2-(meth)acryloyloxypropyl hexahydrophthalic acid, 2-(meth)acryloyloxypropyl phthalic acid, and 2-(meth)acryloyloxypropyl maleic acid.

[0053] Examples of the above-mentioned radical polymerizable oligomers or radical polymers include alkyd (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, urethane-modified (meth)acrylate, ketone-modified (meth)acrylate, polydiallyl phthalate, neopentyl glycol oligo(meth)acrylate, 1,4-butanediol oligo(meth)acrylate, 1,6-hexanediol oligo(meth)acrylate, trimethylolpropane oligo(meth)acrylate, pentaerythritol oligo(meth)acrylate, unsaturated polyester, polyether (meth)acrylate, acrylic resins with unreacted unsaturated groups, unsaturated polyethers, unsaturated polyamides, unsaturated polyurethanes, acrylic-modified phenolic resins, and acrylic amine compounds. The above-mentioned epoxy (meth)acrylate may be a modified epoxy (meth)acrylate such as rosin-modified epoxy (meth)acrylate. Furthermore, if these compounds do not have polymerizable functional groups, they can be used as the non-polymerizable binder oligomers or polymers described above.

[0054] The viscosity of the above radical polymerizable oligomer at 25°C is preferably 3,000 to 10,000 dPa·s, more preferably 3,000 to 8,000 dPa·s, and even more preferably 3,000 to 6,000 dPa·s. When the viscosity is 3,000 dPa·s or higher, the viscosity of the conductive ink tends to increase, and a thick conductive layer can be easily formed. When the viscosity is 10,000 dPa·s or lower, the printability is excellent.

[0055] The above binder component preferably contains a photopolymerization initiator. The above photopolymerization initiator may be used alone or two or more types.

[0056] Examples of the above-mentioned photopolymerization initiators include radical photopolymerization initiators, cationic photopolymerization initiators, and anionic photopolymerization initiators. One type of photopolymerization initiator may be used, or two or more types may be used.

[0057] Examples of the radical photopolymerization initiators mentioned above include acylphosphine oxide photopolymerization initiators, benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, and quinone photopolymerization initiators.

[0058] Examples of acylphosphine oxide photopolymerization initiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and ethylphenyl(2,4,6-trimethylbenzoyl)phosphinate. Examples of benzoin ether photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1,2-diphenylethane-1-one. Examples of acetophenone photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, 4-(t-butyl)dichloroacetophenone, and 2-(dimethylamino)-2-(4-methylphenyl)methyl-1-4-(4-morpholino)phenyl-1-butanone. Examples of α-ketol photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. An example of an aromatic sulfonyl chloride photopolymerization initiator is 2-naphthalenesulfonyl chloride. Examples of photoactive oxime photopolymerization initiators include oxime ester compounds such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime, 1,2-octadione, and 1-[4-(phenylthio)phenyl]-,2-(o-benzoyloxime). Examples of benzoin photopolymerization initiators include benzoin. Examples of benzyl photopolymerization initiators include benzyl. Examples of benzophenone photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, and polyvinylbenzophenone. Examples of ketal photopolymerization initiators include benzyldimethylketal.Examples of thioxanthone photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethyl-9H-thioxanthene-9-one, and dodecylthioxanthone. Examples of quinone photopolymerization initiators include 9,10-dibutoxyanthracene.

[0059] The above-mentioned photopolymerization initiator preferably includes one or more selected from the group consisting of acylphosphine oxide photopolymerization initiators, photoactive oxime photopolymerization initiators, and quinone photopolymerization initiators, and more preferably includes acylphosphine oxide photopolymerization initiators, photoactive oxime photopolymerization initiators, and quinone photopolymerization initiators. In these cases, the curing rate by active energy rays is fast, and a sufficiently cured conductive layer can be obtained even if it is thick. The content ratio of one or more selected from the group consisting of acylphosphine oxide photopolymerization initiators, photoactive oxime photopolymerization initiators, and quinone photopolymerization initiators is preferably 50% by mass or more, more preferably 55% by mass or more, and may be 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of photopolymerization initiators (or the total content ratio of photopolymerization initiators and sensitizers if sensitizers are included) (100% by mass).

[0060] The above photopolymerization initiator may be used as a sensitizer. The content of the above photopolymerization initiator (or the total content of the photopolymerization initiator and sensitizer if a sensitizer is included) is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total amount of binder components (100% by mass). The above content is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, and may be 28% by mass or less or 25% by mass or less.

[0061] By incorporating polymerization inhibitors into conductive inks, storage stability can be improved. Preferred polymerization inhibitors include radical polymerization inhibitors, such as hydroquinones (e.g., hydroquinone, methylhydroquinone, p-tert-butylcatechol, mono-tert-butylhydroquinone); phenols (e.g., hydroquinone monomethyl ether, di-tert-butyl-p-cresol, 4-methoxyphenol, di-tert-butylhydroxytoluene, 2,6-di-tert-butyl-4-methylphenol); quinones (e.g., benzoquinone, p-benzoquinone, naphthoquinone, p-toluquinone); copper salts (e.g., copper naphthenate); phenothiazine; phenoxazine; naphthylamine; cuprous chloride; nitrosophenylhydroxyamine aluminum salt, diphenylnitrosamine, ammonium N-nitrosophenylhydroxylamine; and nitrosamine compounds. Only one polymerization inhibitor may be used, or two or more may be used.

[0062] The content of the polymerization inhibitor is preferably 0.5 to 15% by mass, more preferably 0.7 to 10% by mass, and even more preferably 1.2 to 8% by mass, based on the total amount (100% by mass) of the binder components. When the content is within the above range, the conductive ink exhibits excellent storage stability, and during curing, it cures quickly and easily forms a conductive layer with excellent conductivity.

[0063] By incorporating a dispersant into a conductive ink, the viscosity of the conductive ink can be adjusted, or the dispersibility of conductive particles can be improved. Examples of the above-mentioned dispersants include acidic dispersants and basic dispersants. Examples of the above-mentioned acidic dispersants include carboxylic acid-based dispersants, sulfonic acid-based dispersants, sulfate ester-based dispersants, and phosphate ester-based dispersants. Furthermore, the above-mentioned acidic functional group may be neutralized with a base such as an amine or hydroxide ion. The above-mentioned acidic dispersant may also be an acidic polymer dispersant containing polymer chains such as polyoxyalkylene chains or polyether chains. Among the above-mentioned acidic dispersants, phosphate ester-based dispersants are preferred. The above-mentioned dispersants may be used alone or in combination of two or more types.

[0064] The content of the above dispersant is preferably 0.5 to 15% by mass, more preferably 1 to 12% by mass, and even more preferably 2 to 10% by mass, relative to the total amount of binder components (100% by mass). When the content is within the above range, the dispersibility of conductive particles is improved, the viscosity of the conductive ink becomes appropriate, and it is easier to form a thick conductive layer.

[0065] The conductive ink described above is preferably solvent-free. That is, it is preferable that the conductive ink does not contain or substantially contains organic solvents. Solvent-free conductive inks do not require a step to volatilize and remove solvents from the conductive ink coating during the process of forming a conductive layer from the conductive ink. Therefore, conductive layers formed from solvent-free conductive inks are suitable for reducing environmental impact. The organic solvents described above do not include compounds that harden upon irradiation with active energy rays and constitute binder components of the conductive layer.

[0066] The above-mentioned organic solvents include, but are not particularly limited to, organic compounds used as solvents; for example, hydrocarbon solvents such as cyclohexane, hexane, and heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone; and alcohol solvents such as methanol, ethanol, butanol, and isopropyl alcohol. The above-mentioned organic solvent may also be a mixed solvent containing two or more organic solvents.

[0067] The content of organic solvents in the conductive ink is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.2% by mass or less, relative to the total amount of conductive ink (100% by mass), and it is particularly preferable that they are substantially absent.

[0068] The viscosity of the conductive ink at 25°C is preferably 1 Pa·s or higher, and more preferably 7 Pa·s or higher. A viscosity of 1 Pa·s or higher facilitates the formation of a thick conductive layer. From the viewpoint of excellent printability, the viscosity is preferably 1000 Pa·s or lower, and more preferably 200 Pa·s or lower. The viscosity at 25°C can be measured using a rheometer equipped with a cone plate (cone angle 1°, φ=40mm).

[0069] The conductive inks described above are inks for flexographic printing, offset printing, or screen printing. Offset printing is a printing method in which ink on the surface of a printing plate is first transferred to a transfer medium such as a blanket, and then printed onto a medium such as a paper substrate. By utilizing the property that water and oil repel each other, an oleophilic image area and an oleophobic non-image area are set up, and after the ink is applied to the plate surface, it is printed onto the medium via the blanket. Examples of the printing plates described above include those having an oleophilic image area and a hydrophilic non-image area on the plate surface, and those having an oleophilic image area and a non-image area made of an oleophobic silicone layer on the plate surface. The former type of printing plate is used in printing methods in which ink and water are supplied to the plate surface. The latter type of printing plate is used in a waterless offset printing method, also known as "waterless printing," in which no water is supplied to the plate surface. The conductive ink of the present invention can be made relatively high in viscosity, which makes it less likely for ink to adhere to non-image areas, and allows for the formation of a thick conductive layer. Furthermore, because it hardens relatively quickly, it hardens sufficiently and forms a conductive layer with excellent conductivity, making it suitable for use in waterless offset printing systems.

[0070] The following describes preferred embodiments for flexographic printing inks, offset printing inks, and screen printing inks, respectively.

[0071] (Ink for flexographic printing) In flexographic printing inks, the D50 of metal particles (A) is preferably 0.5 to 10 μm, more preferably 1 to 8 μm, even more preferably 2 to 7 μm, and particularly preferably 3 to 7 μm. The D50 of metal particles (B) is preferably 0.4 to 7 μm, more preferably 0.5 to 6 μm, and even more preferably 1 to 5 μm.

[0072] In flexographic printing inks, the mass ratio of metal particles (A) to metal particles (B) [metal particles (A) / metal particles (B)] is preferably 1.1 to 99, more preferably 1.5 to 60, even more preferably 2 to 40, and particularly preferably 4 to 20.

[0073] In flexographic printing inks, the conductive particles preferably include silver particles and silver-coated copper particles from the viewpoint of achieving a superior balance of conductivity in the conductive layer. The metal particles (A) and (B) may each be silver particles and silver-coated copper particles, or silver-coated copper particles and silver particles.

[0074] In flexographic printing inks, the mass ratio of silver particles to silver-coated copper particles [silver particles / silver-coated copper particles] is preferably 1.1 to 30, more preferably 1.5 to 25, and even more preferably 2 to 20.

[0075] In flexographic printing inks, the content of the polyfunctional polymerizable compound is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of the total amount of conductive particles. The content is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less.

[0076] In flexographic printing inks, the content of the polyfunctional polymerizable compound is preferably 5% by mass or more, and more preferably 10% by mass or more, based on the total amount (100% by mass) of the conductive ink. The content is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0077] In flexographic printing inks, the content of the polyfunctional polymerizable compound in the binder component is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and particularly preferably 60% by mass or more, based on the total amount (100% by mass) of the binder component. The above content is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0078] In flexographic printing inks, the content of the above-mentioned photopolymerization initiator (or the total content of the photopolymerization initiator and sensitizer if a sensitizer is included) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the total amount of binder components (100% by mass). The above content is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0079] In flexographic printing inks, the content of the polymerization inhibitor is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 2 to 8% by mass, based on the total amount of binder components (100% by mass).

[0080] In flexographic printing inks, the content of the above-mentioned dispersant is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, and even more preferably 4 to 12% by mass, based on the total amount of binder components (100% by mass).

[0081] (Ink for offset printing) In offset printing inks, the metal particle D50 is preferably 0.5 to 10 μm, more preferably 1 to 8 μm, even more preferably 2 to 7 μm, and particularly preferably 3 to 7 μm.

[0082] In offset printing inks, the content of the polyfunctional polymerizable compound is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the total amount of conductive particles. The content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less.

[0083] In offset printing inks, the content of the polyfunctional polymerizable compound is preferably 1% by mass or more, and more preferably 3% by mass or more, based on the total amount (100% by mass) of the conductive ink. The content is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0084] In offset printing inks, the content of the polyfunctional polymerizable compound in the binder component is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total amount (100% by mass) of the binder component. The content is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0085] In offset printing inks, it is preferable to include the above-mentioned radical polymerizable oligomer as the other polyfunctional polymerizable compound. The radical polymerizable oligomer is preferably epoxy (meth)acrylate, more preferably modified epoxy (meth)acrylate, and even more preferably rosin-modified epoxy (meth)acrylate.

[0086] In offset printing inks, the content of the radical polymerizable oligomer is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, and particularly preferably 60% by mass or more, based on the total amount of binder components (100% by mass). When the above content is 50% by mass or more, the viscosity of the conductive ink tends to increase, and a thick conductive layer can be easily formed by offset printing. The above content is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 70% by mass or less. When the above content is 90% by mass or less, the printability is excellent.

[0087] In offset printing inks, the content ratio of the above-mentioned photopolymerization initiator (or the total content ratio of the photopolymerization initiator and sensitizer if a sensitizer is included) is preferably 2% by mass or more, more preferably 5% by mass or more, based on the total amount of binder components (100% by mass). The above content ratio is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0088] In offset printing inks, the content of the polymerization inhibitor is preferably 0.5 to 10% by mass, more preferably 0.7 to 8% by mass, and even more preferably 1 to 5% by mass, based on the total amount of binder components (100% by mass).

[0089] (Screen printing ink) In the screen printing ink, the D50 of metal particles (A) is preferably 0.5 to 10 μm, more preferably 1 to 9 μm, even more preferably 2 to 8.5 μm, and particularly preferably 4 to 8 μm. The D50 of metal particles (B) is preferably 0.4 to 8 μm, more preferably 1 to 7.5 μm, and even more preferably 3 to 7 μm.

[0090] In the ink for screen printing, the mass ratio of metal particles (A) to metal particles (B) [metal particles (A) / metal particles (B)] is preferably 0.05 to 0.99, more preferably 0.07 to 0.7, even more preferably 0.1 to 0.5, and particularly preferably 0.2 to 0.4.

[0091] In the screen printing ink, the content of the polyfunctional polymerizable compound is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the total amount of conductive particles. The content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less.

[0092] In the screen printing ink, the content of the polyfunctional polymerizable compound is preferably 1% by mass or more, and more preferably 3% by mass or more, based on the total amount (100% by mass) of the conductive ink. The content is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0093] In the ink for screen printing, the content of the polyfunctional polymerizable compound in the binder component is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and particularly preferably 25% by mass or more, based on the total amount of the binder component (100% by mass). The above content is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less.

[0094] In screen printing inks, it is preferable to include the radical polymerizable oligomer as one of the other polyfunctional polymerizable compounds. The content of the radical polymerizable oligomer is preferably 10% by mass or more, and more preferably 15% by mass or more, based on the total amount (100% by mass) of the binder components. When the content is 10% by mass or more, the viscosity of the conductive ink tends to increase, and a thick conductive layer can be easily formed by screen printing. The content is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. When the content is 50% by mass or less, the printability is excellent.

[0095] In screen printing inks, it is preferable to include the above-mentioned radical polymerizable monomer as the above-mentioned other polyfunctional polymerizable compound. The above-mentioned radical polymerizable monomer is: (Meth)acrylic acid esters are preferred, more preferably (meth)acrylic acid esters having substituents in the ester portion, and even more preferably (meth)acrylic acid esters having a carboxyl group in the ester portion.

[0096] In screen printing inks, the content of the radical polymerizable monomer is preferably 1% by mass or more, and more preferably 3% by mass or more, based on the total amount of binder components (100% by mass). When the content is 1% by mass or more, a sufficiently cured conductive layer can be easily formed by screen printing. When the content is 10% by mass or less, and more preferably 8% by mass or less, the printability is excellent.

[0097] In screen printing inks, the content of the above-mentioned photopolymerization initiator (or the total content of the photopolymerization initiator and sensitizer if a sensitizer is included) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and particularly preferably 20% by mass or more, based on the total amount of binder components (100% by mass). The above content is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[0098] In screen printing inks, the content of the polymerization inhibitor is preferably 0.5 to 15% by mass, more preferably 1.2 to 10% by mass, and even more preferably 3 to 8% by mass, based on the total amount of binder components (100% by mass).

[0099] [Printed material] The printed material of the present invention comprises, for example, a substrate and a conductive printing layer provided on at least one surface of the substrate. The conductive printing layer contains the conductive particles and a binder component. The binder component includes a crosslinked structure derived from a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranched structure. The printed material of the present invention can be manufactured, for example, by printing the conductive ink of the present invention onto a paper substrate. The binder component is formed, for example, by curing the binder component in the conductive ink of the present invention by irradiation with active energy rays.

[0100] Examples of the above-mentioned substrates include paper substrates, plastic substrates, ceramics, and metal substrates. Examples of the above-mentioned paper substrates include coated paper, uncoated paper, and various processed papers such as synthetic paper, polyethylene coated paper, impregnated paper, water-resistant paper, insulating paper, and stretchable paper. Examples of the above-mentioned plastic substrates include substrates made from plastics commonly used for tags and cards, such as polyester, polyethylene, polypropylene, vinyl chloride, vinylidene chloride, polystyrene, vinyl alcohol, ethylene-vinyl alcohol, nylon, polyimide, and polycarbonate.

[0101] The thickness of the conductive printing layer is, for example, 1 μm or more, preferably 3 μm or more, and more preferably 5 μm or more, and is appropriately set depending on the printing method. The conductive ink of the present invention can form a conductive printing layer with a thickness of 1 μm or more and excellent conductivity, and can exhibit the conductivity required for conductive circuits. From the viewpoint of sufficient curing, the thickness of the conductive printing layer is, for example, 20 μm or less, preferably 15 μm or less, and more preferably 10 μm or less.

[0102] The resistivity (surface resistivity) of the conductive printed layer described above is not particularly limited, but is 1.0 × 10⁻⁶. -3 It is preferably Ω·cm or less, and more preferably 5.0 × 10 -4 Ω·cm or less, more preferably 1.0 × 10⁻⁶ -4 Ω·cm or less, particularly preferably 1.0 × 10⁻⁶ -5The resistance is less than or equal to Ω·cm. The above resistance value is 1.0 × 10 -3 If the resistivity is Ω·cm or less, the conductive circuit can exhibit the required conductivity. The above resistivity can be measured using the four-terminal method over a 3cm gap on the surface of the conductive printed layer.

[0103] The conductive printed layer described above can be used as a conductive circuit. By forming the conductive printed layer on a substrate, a communication device can be obtained in which the conductive printed layer is a conductive circuit. The communication device can be used as an antenna in which the conductive circuit functions as an antenna circuit capable of reflecting and / or absorbing electromagnetic waves. The substrate described above can be used as described above.

[0104] The above-mentioned communication equipment, for example, has the conductive circuit and IC module mounted together on a base material. As contactless ID, RFID, contactless IC cards, contactless IC tags, data carriers (recording media), and wireless cards use electromagnetic waves to identify individuals and transmit / receive data between them and a reader or reader / writer. Their applications include ID management and history management in toll collection systems, and location management in road usage management systems and cargo / package tracking and management systems.

[0105] The conductive ink of the present invention allows for the efficient formation of large-area conductive printed layers by flexographic printing, offset printing, and screen printing. Therefore, the communication device can be used not only as a communication device capable of communicating low-frequency electromagnetic waves such as contactless ID, but also as a communication device capable of communicating high-frequency electromagnetic waves (microwaves, millimeter waves). For example, by forming the conductive printed layer on a substrate, an antenna can be obtained comprising a substrate and the conductive printed layer provided on at least one surface of the substrate. The antenna circuit of the conductive printed layer can be fabricated using metasurface technology. For example, the conductive printed layer can be formed on an indoor or outdoor wall to form an antenna that receives electromagnetic waves. This antenna can receive large amounts of electromagnetic waves, resulting in high communication strength even when the number of communication cells or base stations mediating electromagnetic wave transmission is small. The installation location of the antenna circuit is not particularly limited; it can be on an indoor wall, on a desk, on a ceiling, or outdoors.

[0106] Furthermore, by forming the conductive printing layer described above on the outer membrane of the balloon's envelope, a balloon equipped with an antenna can be created. Conventionally, conductive layers are known to be formed by methods such as etching, but because envelopes are large in size and their material can be corroded by alkali, it has been practically impossible to form an antenna on an envelope by etching. However, by using the conductive ink of the present invention, large-area antenna circuits can be efficiently formed by general-purpose printing methods such as flexographic printing, offset printing, and screen printing. By keeping a balloon equipped with an antenna circuit stationed in the air, it can function as a communication base station, enabling communication between multiple points in space and on the ground, and can serve as an alternative to communication satellites. In addition, at least a part of the envelope may be inflatable. Being inflatable allows the envelope to be inflated to maximize the antenna area when the antenna is in use, creating an optimal shape for antenna use, while when the antenna is not in use, it can be shaped to be optimal for the balloon's original performance, such as for stationary or mobile use. The outer membrane of the envelope may be single-layered or multi-layered. The conductive printed layer, which acts as the antenna, may crack or break due to repeated expansion and contraction of the envelope. Therefore, if the outer layer of the envelope is multi-layered, the outermost layer should have high rigidity, and the antenna should be mounted on the surface of this outermost layer, while the inner layer located inside the outermost layer should be a layer with excellent elasticity. With such a configuration, cracks or breaks in the antenna are less likely to occur even when the envelope is expanded and contracted due to its inflatable function. Furthermore, from the viewpoint of protecting the antenna equipment, the antenna substrate may be installed between the outermost layer and the inner layer.

[0107] The shape of the envelope described above is not particularly limited; it may be a general spherical shape, a columnar shape, an ellipsoidal shape like that of an airship, a rectangular parallelepiped, or other shapes. Furthermore, the position, area, shape, and number of regions of the conductive printed layer formed on the surface of the envelope are not particularly limited and can be adjusted as appropriate according to the purpose. When using the antenna, conductive printed layers may be formed on the upper and / or lower surfaces of the envelope from the viewpoint of maximizing its performance as a communication base station.

[0108] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. [Examples]

[0109] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples. Note that all amounts (parts by mass) refer to the amounts of each component described.

[0110] Example 1 (Preparation of flexographic printing ink 1) 14.0 parts by mass of polyfunctional polymerizable compound (product name "CN2302", manufactured by Sartomer, 16-functional hyperbranched polyester acrylate oligomer, viscosity at 25°C: 300 mPa·s, mass-average molecular weight 1500), and as photopolymerization initiator (A), acyl phosphine oxide photopolymerization initiator (product name "SPEEDCURE TPO-L", manufactured by LAMBSON), quinone photopolymerization initiator (product name "Anthracure UVS-581", manufactured by Air Water Performance Chemicals Inc.), quinone photopolymerization initiator (product name "Anthracure A binder component was prepared by stirring in a dissolver until completely mixed 4.5 parts by mass of UVS-1331 (manufactured by Air Water Performance Chemicals Inc.) and a photoactive oxime photopolymerization initiator (trade name "Oxo-01", manufactured by BASF), and 1.0 part by mass of a polymerization inhibitor (trade name "Q-1301", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., a nitrosamine compound). Next, 2.0 parts by mass of a phosphate ester dispersant (trade name "ED-153", manufactured by Kusumoto Chemicals Inc.), 71.0 parts by mass of silver-coated copper particles (D50 (laser diffraction method): 4-6 μm, flake-like) as metal particles (A), and silver particles (D50 (laser diffraction method): 2-5 μm, packing bulk density: 3.5-5.5 g / cm³) as metal particles (B). 3 , Specific surface area (BET method): 0.3~1.5m 27.5 parts by mass of (g, spherical) was added, and the mixture was stirred with a dissolver until completely mixed to obtain a flexographic ink 1 which is an active energy ray-curable type.

[0111] (Formation of conductivity) Flexographic ink 1 was flexographically printed on coated paper using a resin flexographic plate and a printing machine (model number "VFX-300D", manufactured by Pexan Co., Ltd.) to form a conductive layer having a predetermined shape so as to have a thickness of about 7 to 10 μm. The above shape is a shape in which a line segment with a spacing of 5 mm and a length of 2.2 cm × width of 1 mm and a semi-circle with a diameter of 2 cm are joined at their ends, and two such shapes are arranged such that the openings of the semi-circles oppose each other and the spacing of the line segments is 5 mm. The above shape has a shape in which four or five line segments extend alternately from the inner peripheral side of the semi-circle toward the opposing semi-circle and do not contact the other semi-circle.

[0112] Example 2 A binder component was prepared in the same manner as in Example 1 except that the blending amounts of various components were changed as shown in Table 1. Next, to the above binder component, 2.0 parts by mass of a phosphate ester-based dispersant (trade name "ED-153", manufactured by Kusumoto Chemical Co., Ltd.), 70.0 parts by mass of silver-coated copper particles (D50 (laser diffraction method): 4 to 5 μm, potato shape) as metal particles (A), and silver-coated copper particles (D50 (laser diffraction method): 2 to 5 μm, bulk density: 3.5 to 5.5 g / cm 3 , specific surface area (BET method): 0.3 to 1.5 m 2 / g, spherical) 9.0 parts by mass was added, and the mixture was stirred with a dissolver until completely mixed to obtain a flexographic ink 2 which is an active energy ray-curable type. Then, a conductive layer was formed in the same manner as in Example 1 except that flexographic ink 2 was used.

[0113] Example 3 A binder component was prepared by stirring 5.0 parts by mass of a polyfunctional polymerizable compound (trade name "CN2302", manufactured by Sartomer, 16-functional hyperbranched polyester acrylate oligomer, viscosity at 25°C: 300 mPa·s, mass-average molecular weight 1500) and a total of 5.0 parts by mass of photopolymerization initiators (B), including acylphosphine oxide photopolymerization initiator (trade name "SPEEDCURE TPO-L", manufactured by LAMBSON), acylphosphine oxide photopolymerization initiator (trade name "Omnirad 819", manufactured by IGM Resins BV), quinone photopolymerization initiator (trade name "Anthracure UVS-1331", manufactured by Air Water Performance Chemicals Inc.), and photoactive oxime photopolymerization initiator (trade name "Oxo-01", manufactured by BASF) in a dissolver until completely mixed. Next, 2.0 parts by mass of a phosphate ester dispersant (product name "ED-153", manufactured by Kusumoto Kasei Co., Ltd.) and 90.0 parts by mass of silver-coated copper particles (particle size: 4-6 μm, flake-shaped) as metal particles were added to the above binder component, and the mixture was stirred with a dissolver until it was completely mixed to obtain an active energy ray curable flexographic printing ink 3. Then, a conductive layer was formed in the same manner as in Example 1, except that flexographic printing ink 3 was used.

[0114] Comparative Example 1 A binder component was prepared by stirring 10.0 parts by mass of acryloylmorpholine as a monofunctional monomer and 5.0 parts by mass of the above photopolymerization initiator (B) in a dissolver until completely mixed. Next, 2.0 parts by mass of a phosphate ester dispersant (trade name "ED-153", manufactured by Kusumoto Chemical Co., Ltd.), 80.0 parts by mass of silver-coated copper particles (D50 (laser diffraction method): 4-6 μm, flake-like) as metal particles (B), and silver particles (D50 (laser diffraction method): 4.7-7.0 μm, apparent density: 0.45-0.75 g / cm³) as metal particles (A). 3 , Specific surface area (BET method): 1.5~1.9m 2Five parts by mass of (1g, flake form) were added and stirred with a dissolver until completely mixed to obtain an active energy ray curable flexographic printing ink 4. Then, a conductive layer was formed in the same manner as in Example 1, except that flexographic printing ink 4 was used.

[0115] Comparative Example 2 A flexographic printing ink 5 that is curable by active energy rays was obtained in the same manner as in Comparative Example 1, except that the above-mentioned photopolymerization initiator (A) was used instead of photopolymerization initiator (B). Then, a conductive layer was formed in the same manner as in Example 1, except that flexographic printing ink 5 was used.

[0116] Example 4 (Preparation of offset printing ink 1) 4.5 parts by mass of polyfunctional polymerizable compound (product name "CN2302", manufactured by Sartomer, 16-functional hyperbranched polyester acrylate oligomer, viscosity at 25°C: 300 mPa·s, mass-average molecular weight 1500), 21.0 parts by mass of rosin-modified epoxy acrylate as a radical polymerizable oligomer (product name "Bamboo Beam UV-24A", manufactured by Harima Chemicals Group Co., Ltd., viscosity at 25°C: 6750 ± 2750 dPa·s), 0.5 parts by mass of leveling agent (product name "Polyflow KL-100", manufactured by Kyoeisha Chemical Co., Ltd., organic modified silicone), 3.0 parts by mass of acylphosphine oxide photopolymerization initiator as a photopolymerization initiator (product name "SPEEDCURE TPO-L", manufactured by Lambson), quinone photopolymerization initiator (product name "Anthracure UVS-581", manufactured by Air Water Performance Chemical Co., Ltd.) and quinone photopolymerization initiator (product name "Anthracure A binder component was prepared by stirring 0.3 parts by mass of UVS-1331 (manufactured by Air Water Performance Chemicals Inc.), 0.2 parts by mass of a photoactive oxime photopolymerization initiator (trade name "Oxo-01", manufactured by BASF), and 0.5 parts by mass of a polymerization inhibitor (trade name "Q-1301", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., a nitrosamine compound) in a dissolver until completely mixed. Next, 70.0 parts by mass of metal particles (silver-coated copper particles, D50 (laser diffraction method): 4-6 μm, flake-shaped) as conductive particles were added to the above binder component and stirred in a dissolver until completely mixed to obtain an active energy ray curable offset printing ink 1.

[0117] (Formation of conductivity) Offset printing ink 1 was used on coated paper using an offset printing press (manufactured by Komori Corporation) with a waterless lithographic plate (product name "TAC-VG", manufactured by Toray Industries, Inc.) to form a conductive layer with the same shape as the flexographic printing described above, with a thickness of approximately 4 μm.

[0118] Example 5 Offset printing ink 2, which is curable by active energy rays, was obtained in the same manner as in Example 4, except that the amounts of various components were changed as shown in Table 2. The dispersant was added to the binder component together with the metal particles. A phosphate ester-based dispersant (product name "ED-153", manufactured by Kusumoto Kasei Co., Ltd.) was used as the dispersant. Then, a conductive layer was formed in the same manner as in Example 4, except that offset printing ink 2 was used.

[0119] Example 6 As shown in Table 2, an active energy ray-curable offset printing ink 3 was obtained in the same manner as in Example 4, except that the proportions of various components were changed. Then, a conductive layer was formed in the same manner as in Example 4, except that offset printing ink 3 was used.

[0120] Example 7 (Preparation of screen printing ink 1) 5.5 parts by mass of polyfunctional polymerizable compound (product name "CN2302", manufactured by Sartomer, 16-functional hyperbranched polyester acrylate oligomer, viscosity at 25°C: 300 mPa·s, mass-average molecular weight 1500), 3.0 parts by mass of high-viscosity oligomer as a radical polymerizable oligomer (product name "VG-901", manufactured by Toshin Oils Co., Ltd., viscosity at 25°C: 4000-6000 dPa·s), 1.0 part by mass of acid-containing monomer (product name "Light Ester HO-MS(N)", manufactured by Kyoeisha Chemical Co., Ltd., 2-methacryloyloxyethyl succinic acid), 0.5 parts by mass of leveling agent (product name "Polyflow KL-100", manufactured by Kyoeisha Chemical Co., Ltd., organically modified silicone), and as a photopolymerization initiator, acyl phosphine oxide photopolymerization initiator (product name "SPEEDCURE"). A binder component was prepared by stirring 3.5 parts by mass of TPO-L (manufactured by LAMBSON), a total of 0.3 parts by mass of quinone photopolymerization initiator (product name "Anthracure UVS-581", manufactured by Air Water Performance Chemicals Inc.) and quinone photopolymerization initiator (product name "Anthracure UVS-1331", manufactured by Air Water Performance Chemicals Inc.), 0.2 parts by mass of photoactive oxime photopolymerization initiator (product name "Oxo-01", manufactured by BASF), and 1.0 part by mass of polymerization inhibitor (product name "Q-1301", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., a nitrosamine compound) in a dissolver until completely mixed. Next, 65.0 parts by mass of silver-coated copper particles (D50 (laser diffraction method): 4-6 μm, flake-shaped) as metal particles (B) and 20.0 parts by mass of silver-coated copper particles (D50 (laser diffraction method): 5-7 μm, flake-shaped) as metal particles (A) were added to the binder component, and the mixture was stirred with a dissolver until it was completely mixed to obtain an active energy ray curable screen printing ink 1.

[0121] (Formation of conductivity) Screen printing ink 1 was screen printed onto coated paper using a resin screen printing plate (product name "ADLESS™", manufactured by Asahi Kasei Corporation) and a printing press (model number "DGO Direct Gravure", manufactured by Mino Group Co., Ltd.) to form a conductive layer with the same shape as the flexographic printing described above, with a thickness of approximately 10 μm.

[0122] Example 8 Screen printing ink 2, which is curable by active energy rays, was obtained in the same manner as in Example 7, except that the amounts of various components were changed as shown in Table 3. The dispersant was added to the binder component together with the metal particles. A phosphate ester-based dispersant (product name "ED-153", manufactured by Kusumoto Kasei Co., Ltd.) was used as the dispersant, and "Tallen 2450" (product name "Tallen 2450", manufactured by Kyoeisha Chemical Co., Ltd.) was used as the thixotropic agent. Then, a conductive layer was formed in the same manner as in Example 7, except that screen printing ink 2 was used.

[0123] [evaluation] The printing inks of the examples and comparative examples were evaluated as described below. The conductive layer was then evaluated based on the following criteria. The evaluation results are shown in Tables 1 to 3. The composition and evaluation of the flexographic printing ink are shown in Table 1, the composition and evaluation of the offset printing ink are shown in Table 2, and the composition and evaluation of the screen printing ink are shown in Table 3.

[0124] (judgment criteria) Based on the following evaluations of "ink suitability," "curability," and "conductivity," a score of "○" was given if all scores were correct, "△" if two scores were correct, and "×" if one or fewer scores were correct.

[0125] (1) Ink suitability For the printing inks prepared in the examples and comparative examples, the dispersibility of conductive particles, viscosity, and fluidity of the ink were observed by manual stirring and visual inspection. A "○" was used if it was determined that the ink was suitable for printing using various printing methods, and a "×" was used if it was determined that the dispersibility, viscosity, and fluidity were unsuitable for printing using various printing methods.

[0126] (2) Curability The thickness of the conductive layer was measured, and if the desired thickness was achieved and the cured film was formed uniformly, it was evaluated as "○" (○), and otherwise as "×" (×).

[0127] (3) Conductivity The resistivity between the two ends (2.2 cm apart) of one line segment on the surface of the conductive layer was measured using a resistivity meter (product name "Low Resistivity Meter MCP-T610", manufactured by Mitsubishi Chemical Corporation) with a four-terminal method. A "○" was used to indicate that resistivity could be measured, and a "×" was used to indicate that resistivity could not be measured.

[0128] [Table 1]

[0129] [Table 2]

[0130] [Table 3]

[0131] Regarding the flexographic printing inks, the conductive inks in the examples were all able to produce a thick, sufficiently cured conductive layer, and conductivity was confirmed. In particular, when metal particles (A) and (B) were used in combination as conductive particles, and a photopolymerization initiator (A) containing a quinone photopolymerization initiator was used as the photopolymerization initiator (Examples 1 and 2), superior curability was achieved, and a conductive layer with excellent conductivity in a thick film was formed. On the other hand, when acryloylmorpholine, which is generally considered to have high curability, was used in place of a polyfunctional polymerizable compound (Comparative Examples 1 and 2), conductivity was not confirmed in the resulting conductive layer, and it was evaluated as having poor conductivity.

[0132] Regarding the inks for offset printing, all of the conductive inks in the examples were able to produce a sufficiently cured conductive layer, and conductivity was confirmed. Furthermore, regarding the inks for screen printing, all of them were able to produce a thick, sufficiently cured conductive layer, exhibiting low resistivity and demonstrating excellent conductivity.

[0133] The following describes variations of the invention relating to this disclosure. [Note 1] Contains conductive particles and binder components, The binder component comprises a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranched structure. The content of the polyfunctional polymerizable compound is 1 part by mass or more per 100 parts by mass of the total amount of conductive particles. Active energy ray-curable conductive ink for flexographic printing, offset printing, or screen printing. [Note 2] The polyfunctional polymerizable compound has 6 to 30 polymerizable functional groups, and is an active energy ray curable conductive ink as described in Note 1. [Note 3] The polyfunctional polymerizable compound has a (meth)acryloyl group as a polymerizable functional group, as described in Note 1 or 2, and is an active energy ray curable conductive ink. [Note 4] The polyfunctional polymerizable compound is a polyester (meth)acrylate compound, as described in Note 3, for active energy ray curable conductive ink. [Note 5] The active energy ray-curable conductive ink according to any one of Notes 1 to 4, wherein the content of the polyfunctional polymerizable compound is 3 to 20% by mass relative to the total amount of the active energy ray-curable conductive ink. [Note 6] The active energy ray-curable conductive ink according to any one of Notes 1 to 5, wherein the content of the conductive particles is 60 to 90% by mass relative to the total amount of the active energy ray-curable conductive ink. [Note 7] The active energy ray curable conductive ink according to any one of Notes 1 to 6, wherein the content of the polyfunctional polymerizable compound is 5% by mass or more based on 100% by mass of the total amount of the binder components. [Note 8] An active energy ray curable conductive ink according to any one of Notes 1 to 7, comprising an acyl phosphine oxide photopolymerization initiator, a photoactive oxime photopolymerization initiator, and a quinone photopolymerization initiator. [Note 9] An active energy ray-curable conductive ink containing a phosphate ester-based dispersant, as described in any one of Notes 1 to 8. [Note 10] An active energy ray-curable conductive ink according to any one of Notes 1 to 9, for use in offset printing, wherein the binder component further comprises epoxy (meth)acrylate. [Note 11] Active energy ray curable conductive ink as described in any one of Notes 1 to 10, for use in waterless offset printing. [Note 12] The system comprises a substrate and a conductive printing layer provided on at least one surface of the substrate. The conductive printed layer comprises conductive particles and a binder component. A printed material wherein the binder component comprises a crosslinked structure derived from a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranched structure. [Note 13] Communication equipment equipped with the printed materials described in Note 12. [Note 14] An antenna equipped with the printed material described in Note 12.

Claims

1. It contains conductive particles and binder components, The binder component comprises a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranched structure. The content of the polyfunctional polymerizable compound is 1 part by mass or more per 100 parts by mass of the total amount of conductive particles. Active energy ray-curable conductive ink for flexographic printing, offset printing, or screen printing.

2. The active energy ray curable conductive ink according to claim 1, wherein the polyfunctional polymerizable compound has 6 to 30 polymerizable functional groups.

3. The active energy ray curable conductive ink according to claim 1 or 2, wherein the polyfunctional polymerizable compound has a (meth)acryloyl group as a polymerizable functional group.

4. The active energy ray curable conductive ink according to claim 3, wherein the polyfunctional polymerizable compound is a polyester (meth)acrylate compound.

5. The active energy ray-curable conductive ink according to claim 1 or 2, wherein the content of the polyfunctional polymerizable compound is 3 to 20% by mass relative to the total amount of the active energy ray-curable conductive ink.

6. The active energy ray-curable conductive ink according to claim 1 or 2, wherein the content of the conductive particles is 60 to 90% by mass relative to the total amount of the active energy ray-curable conductive ink.

7. The active energy ray-curable conductive ink according to claim 1 or 2, wherein the content of the polyfunctional polymerizable compound is 5% by mass or more based on 100% by mass of the total amount of the binder component.

8. An active energy ray-curable conductive ink according to claim 1 or 2, comprising an acyl phosphine oxide photopolymerization initiator, a photoactive oxime photopolymerization initiator, and a quinone photopolymerization initiator.

9. An active energy ray-curable conductive ink according to claim 1 or 2, comprising a phosphate ester-based dispersant.

10. An active energy ray-curable conductive ink according to claim 1 or 2, for use in offset printing, wherein the binder component further comprises epoxy (meth)acrylate.

11. The active energy ray-curable conductive ink according to claim 1 or 2, for use in waterless offset printing.

12. The device comprises a substrate and a conductive printing layer provided on at least one surface of the substrate. The conductive printed layer comprises conductive particles and a binder component. A printed material wherein the binder component comprises a crosslinked structure derived from a polyfunctional polymerizable compound having a dendrimer structure and / or a hyperbranched structure.

13. A communication device comprising the printed material described in claim 12.

14. An antenna comprising the printed material described in claim 12.

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