Conductive composition

Abstract

To provide a conductive composition allowing formation of a conductive coating film combining conductivity with brightness.SOLUTION: A conductive composition comprises a conductive polymer, a metal oxide, and a binder, wherein the solids fraction of the conductive polymer relative to the total solids is 1 wt.% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an electrically conductive composition. [Background technology]

[0002] Conductive polymers are materials with excellent electrical conductivity and are widely used in applications requiring electrical conductivity, such as touch panels for electronic devices. However, because conductive polymers are colored, increasing the amount of conductive polymer used to improve conductivity tends to discolor the resulting components and impair their design. Carbon materials such as carbon nanotubes can also be used as conductive materials, but they are colored like conductive polymers.

[0003] Patent Document 1 discloses an anti-static sheet that reduces the influence of the color of the conductive material by forming a coating film containing a conductive polymer, carbon nanotubes, and silica nanoparticles on a substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-093621 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a conductive composition for forming a conductive coating film that has both electrical conductivity and brightness. [Means for solving the problem]

[0006] The present inventors have discovered that, in a conductive composition containing a conductive polymer, a metal oxide, and a binder, by setting the blending amount of the conductive polymer within a certain range, a conductive coating film that achieves both conductivity and brightness can be formed, and have completed the present invention.

[0007] That is, the present invention includes the following aspects. <1> A conductive composition comprising a conductive polymer, a metal oxide and a binder, wherein the proportion of the solid content of the conductive polymer relative to the total solid content is 1% by weight or less. <2> Item 2. The conductive composition according to item 1, further comprising a carbon material, wherein the ratio of the total solid content of the conductive polymer and the carbon material to the total solid content is 1 wt % or less. <3> Item 3. The conductive composition according to item 1 or 2, wherein the solid content of the metal oxide is 200 to 1000 parts by weight per 100 parts by weight of the total solid content of the conductive polymer and the carbon material. <4> Item 3. The conductive composition according to item 1 or 2, wherein the conductive polymer is one or more selected from the group consisting of polythiophene, polypyrrole, and polyaniline. <5> Item 3. The conductive composition according to item 1 or 2, wherein the metal oxide is one or more selected from the group consisting of zinc oxide, titanium oxide, phosphorus-doped tin oxide, antimony-doped tin oxide, and cerium oxide. <6> Item 3. The conductive composition according to item 1 or 2, wherein the binder is one or more selected from the group consisting of acrylic resins, polyurethane resins, polyester resins, styrene resins, epoxy resins, vinyl acetate resins, vinyl chloride resins, silicone resins, and fluorine-based resins. <7> Item 3. The conductive composition according to item 2, wherein the carbon material is one or more selected from the group consisting of carbon nanotubes, graphene, and fullerenes. <8> Item 3. The conductive composition according to item 1 or 2, wherein the conductive polymer has an average dispersed particle size of 0.1 to 1000 nm. <9> Item 3. The conductive composition according to item 1 or 2, wherein the metal oxide has an average dispersed particle size of 1 to 10,000 nm. <10> Item 3. The conductive composition according to item 1 or 2, wherein the solid content is 2 to 50%. [Effects of the Invention]

[0008] The conductive composition of the present invention can form a conductive coating film that is both conductive and bright. DETAILED DESCRIPTION OF THE INVENTION

[0009] <<Conductive composition>> The conductive composition of the present invention is characterized by containing a conductive polymer, a metal oxide, and a binder, and the proportion of the solid content of the conductive polymer relative to the total solid content is 1% by weight or less.

[0010] <Conductive polymer> The conductive polymer may be any conventionally known conductive polymer, including, for example, polythiophene, polypyrrole, polyaniline, polyacetylene, polyphenylene vinylene, polynaphthalene, derivatives thereof, and complexes of these with dopants.

[0011] The conductive polymer is preferably a conductive polymer containing at least one thiophene ring in the molecule. This is because the inclusion of a thiophene ring in the molecule makes it easier to produce a molecule with high conductivity. As the conductive polymer, poly(3,4-disubstituted thiophene) or a complex of poly(3,4-disubstituted thiophene) and a polyanion as a dopant is more preferred. This is because they have extremely excellent conductivity and chemical stability. Furthermore, when poly(3,4-disubstituted thiophene) or a complex of poly(3,4-disubstituted thiophene) and a polyanion is contained, a conductive coating film can be formed at low temperature and in a short time, resulting in excellent productivity.

[0012] As the poly(3,4-disubstituted thiophene), poly(3,4-dialkoxythiophene) or poly(3,4-alkylenedioxythiophene) is particularly preferred. As the poly(3,4-dialkoxythiophene) or poly(3,4-alkylenedioxythiophene), the following formula (I):

[0013] [ka]

[0014] Preferred is a cationic form of polythiophene consisting of repeating structural units of the formula: 1 and R 2 are each independently a hydrogen atom or C 1-4 or R 1 and R 2 When C is bonded 1-4 represents an alkylene group of the formula C 1-4 The alkyl group in R is not particularly limited, but examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. 1 and R 2 If C is bonded 1-4 The alkylene group in is not particularly limited, but examples thereof include a methylene group, a 1,2-ethylene group, a 1,3-propylene group, a 1,4-butylene group, a 1-methyl-1,2-ethylene group, a 1-ethyl-1,2-ethylene group, a 1-methyl-1,3-propylene group, and a 2-methyl-1,3-propylene group. Among these, a methylene group, a 1,2-ethylene group, and a 1,3-propylene group are preferred, and a 1,2-ethylene group is more preferred. 1-4 and alkyl groups of C 1-4 The alkylene group may have some of its hydrogen atoms substituted. 1-4 As the polythiophene having an alkylene group, poly(3,4-ethylenedioxythiophene) is particularly preferred.

[0015] A polyanion is preferably used as the dopant. The polyanion forms an ion pair with the polythiophene (derivative) to form a complex, enabling the polythiophene (derivative) to be stably dispersed in water. The polyanion is not particularly limited, but examples thereof include carboxylic acid polymers (e.g., polyacrylic acid, polymaleic acid, polymethacrylic acid, etc.) and sulfonic acid polymers (e.g., polystyrene sulfonic acid, polyvinyl sulfonic acid, polyisoprene sulfonic acid, etc.). These carboxylic acid polymers and sulfonic acid polymers may also be copolymers of vinyl carboxylic acids and vinyl sulfonic acids with other polymerizable monomers, such as acrylates, styrene, vinyl naphthalene, and other aromatic vinyl compounds. Among these, polystyrene sulfonic acid is particularly preferred.

[0016] The weight-average molecular weight of the polystyrene sulfonic acid is preferably 1,000 to 2,000,000, and more preferably 2,000 to 500,000. If polystyrene sulfonic acid with a molecular weight outside this range is used, the dispersion stability of the polythiophene-based conductive polymer in water may decrease. The weight-average molecular weight is a value measured by gel permeation chromatography (GPC).

[0017] Polyaniline can also be used as the conductive polymer. Self-doped polyaniline or a complex with a dopant is preferred. Self-doped aniline can be exemplified by self-doped polyaniline sulfonic acid. Dopants can include organic acids such as toluenesulfonic acid and acetic acid, and inorganic acids such as hydrochloric acid and sulfuric acid.

[0018] The conductive polymer is particularly preferably a composite of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, because of its excellent transparency and conductivity.

[0019] The average dispersed particle diameter of the conductive polymer is preferably 0.1 to 1000 nm, more preferably 0.5 to 100 nm, even more preferably 1 to 10 nm, and particularly preferably 1 to 5 nm. Within the above range, the conductive coating film tends to have excellent conductivity. The average dispersed particle diameter in the present invention is the particle diameter at 50% of the cumulative number when the dispersion in the conductive composition is measured by dynamic light scattering.

[0020] The conductivity of the conductive polymer is preferably 0.05 to 2000 S / cm, more preferably 0.5 to 2000 S / cm, and even more preferably 100 to 2000 S / cm. Within this range, the conductive coating film tends to have excellent conductivity.

[0021] The ratio of the solid content of the conductive polymer to the total solid content of the conductive composition is 1 wt % or less, preferably 0.01 to 0.8 wt %, more preferably 0.05 to 0.6 wt %, and still more preferably 0.1 to 0.4 wt %. If the ratio of the solid content of the conductive polymer to the total solid content exceeds 1 wt %, a conductive coating film that is both conductive and bright cannot be obtained.

[0022] <Metal oxides> By including a metal oxide in the conductive composition, the conductivity of the conductive coating film made of the conductive composition can be improved while maintaining its brightness. It is believed that the metal oxide improves conductivity by serving as an electrical conduction path between conductive polymers, but the present invention is not limited to this mechanism. The metal oxide is not particularly limited as long as it is an oxide of a metal that is conductive. Examples of metals that constitute the metal oxide include zinc, titanium, tin, cerium, and indium. The metal oxide may also be doped with phosphorus, antimony, aluminum, gallium, fluorine, or the like. Specific examples of the metal oxide include zinc oxide, titanium oxide, phosphorus-doped tin oxide, antimony-doped tin oxide, cerium oxide, and gallium oxide. The metal oxide may also be surface-treated with silica, alumina, titania, or the like.

[0023] The metal oxide to be used is preferably in the form of particles. The specific shape of the metal oxide is not particularly limited, and for example, spherical, flat, or irregularly shaped metal oxides can be used.

[0024] The average dispersed particle size of the metal oxide is preferably 1 to 10,000 nm, more preferably 5 to 1,000 nm, and even more preferably 10 to 500 nm. If the particle size is less than 1 nm, the particles tend to aggregate easily and become unstable in the conductive composition. If the particle size exceeds 10,000 nm, it tends to be difficult to achieve both brightness and conductivity in the conductive coating film.

[0025] The proportion of the metal oxide relative to the total solid content of the conductive composition is preferably 0.1 to 15% by weight, more preferably 1.5 to 10% by weight, and even more preferably 2 to 8% by weight.

[0026] In the conductive composition, the solid content of the metal oxide is preferably 200 to 1000 parts by weight, more preferably 400 to 950 parts by weight, and more preferably 600 to 900 parts by weight, per 100 parts by weight of the total solid content of the conductive polymer and carbon material. If the solid content of the metal oxide is less than 200 parts by weight, the conductivity of the composition tends to decrease, and if it exceeds 1000 parts by weight, the conductivity of the composition also tends to decrease.

[0027] <Binder> The binder is not particularly limited as long as it is a resin binder, and thermoplastic resins or thermosetting resins can be used. Examples of thermoplastic resins include acrylic resins, polyurethane resins, polyester resins, polyolefin resins, styrene resins, vinyl acetate resins, vinyl chloride resins, and fluorine-based resins. Examples of thermosetting resins include silicone resins, epoxy resins, phenolic resins, amino resins, and polyimide resins, as well as thermoplastic resins having reactive functional groups. Conductive films made of conductive compositions containing these binders have good affinity for substrates. Furthermore, the binder may be a water-dispersible resin or a curable resin that hardens after application to a substrate. When the binder is a water-dispersible resin, the water-dispersible resin may be dispersed as a result of the addition of hydrophilic functional groups to the resin, or may be forcibly dispersed using an emulsifier. These binders may be used alone or in combination of two or more.

[0028] Examples of acrylic resins include (meth)acrylic resins, vinyl ester resins, etc. These acrylic resins may be polymers containing, as constituent monomers, polymerizable monomers having an acid group such as a carboxyl group, an acid anhydride group, a sulfonic acid group, or a phosphoric acid group, and examples thereof include homopolymers or copolymers of polymerizable monomers having an acid group, and copolymers of polymerizable monomers having an acid group and copolymerizable monomers.

[0029] The (meth)acrylic resin may be polymerized with a copolymerizable monomer as long as it contains a (meth)acrylic monomer as the main constituent monomer (for example, 50 mol% or more), and in this case, at least one of the (meth)acrylic monomer and the copolymerizable monomer may have an acid group. Examples of (meth)acrylic resins include (meth)acrylic monomers having an acid group [such as (meth)acrylic acid, sulfoalkyl (meth)acrylates, and sulfonic acid group-containing (meth)acrylamides] or copolymers thereof; copolymers of (meth)acrylic monomers that may have an acid group with other polymerizable monomers having an acid group [such as other polymerizable carboxylic acids, polymerizable polycarboxylic acids or anhydrides, and vinyl aromatic sulfonic acids] and / or copolymerizable monomers [such as (meth)acrylic acid alkyl esters, glycidyl (meth)acrylate, (meth)acrylonitrile, and aromatic vinyl monomers]; copolymers of other polymer monomers having an acid group with (meth)acrylic copolymerizable monomers [such as (meth)acrylic acid alkyl esters, hydroxyalkyl (meth)acrylates, glycidyl (meth)acrylate, and (meth)acrylonitrile]; rosin-modified urethane acrylates; specially modified acrylic resins; urethane acrylates; epoxy acrylates; and urethane acrylate emulsions.

[0030] Among these (meth)acrylic resins, (meth)acrylic acid-(meth)acrylic acid ester polymers (acrylic acid-methyl methacrylate copolymers, etc.), (meth)acrylic acid-(meth)acrylic acid ester-styrene copolymers (acrylic acid-methyl methacrylate-styrene copolymers, etc.), etc. are preferred.

[0031] The polyurethane resin is not particularly limited as long as it is a polymer compound obtained by copolymerizing a compound having an isocyanate group and a compound having a hydroxyl group, and examples thereof include ester-ether polyurethane, ether polyurethane, polyester polyurethane, carbonate polyurethane, and acrylic polyurethane.

[0032] The polyester resin is not particularly limited as long as it is a polymer compound obtained by polycondensation of a compound having two or more carboxyl groups in the molecule and a compound having two or more hydroxyl groups, and examples thereof include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate.

[0033] The polyolefin resin is not particularly limited, but examples thereof include polyethylene, polypropylene, chlorinated polypropylene, maleic anhydride-modified polypropylene, maleic anhydride-modified chlorinated polypropylene, and ethylene-vinyl acetate copolymer.

[0034] The styrene-based resin is not particularly limited as long as it is a resin whose main component is styrene, and examples thereof include polystyrene, acrylonitrile-styrene copolymer (AS), and acrylonitrile-butadiene-styrene copolymer (ABS).

[0035] The vinyl acetate resin is not particularly limited as long as it is a resin obtained by polymerization of vinyl acetate, and examples thereof include polyvinyl acetate and ethylene-vinyl acetate copolymer.

[0036] The vinyl chloride resin is not particularly limited as long as it is a resin obtained by polymerization of vinyl chloride, and examples thereof include polyvinyl chloride, ethylene vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, and the like.

[0037] Examples of fluorine-based resins include polytetrafluoroethylene, polyvinylidene fluoride, Teflon (registered trademark), and polyvinyl fluoride.

[0038] Examples of silicone-based resins include oligomers of alkoxysilanes formed by condensation of alkoxysilane monomers represented by the following formula (I), which have one or more siloxane bonds (Si—O—Si) in each molecule. SiR 1 4(I) (In the formula, R1 is hydrogen, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an aryl group having 6 to 20 carbon atoms which may have a substituent. 1 At least one of these is an alkoxy group having 1 to 4 carbon atoms or a hydroxyl group.

[0039] In formula (I), R 1 Examples of the alkoxy group of R include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. 1 Examples of the alkyl group of R include a methyl group, an ethyl group, a propyl group, a normal butyl group, a tertiary butyl group, a pentyl group, and a hexyl group. 1 The aryl group includes a phenyl group, a tolyl group, and a benzyl group.

[0040] Specific examples of the monomer represented by formula (I) include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, Examples of suitable silanes include 3-isocyanatepropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, diisopropyldimethoxysilane, isobutyltrimethoxysilane, diisobutyldimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Among these, tetramethoxysilane and tetraethoxysilane are preferred.

[0041] The structure of the silicone resin is not particularly limited, and may be linear or branched. The silicone resin may be a condensate of one type of monomer represented by formula (I), or may be a condensate of two or more types of monomers. Specific examples of the silicone resin include methyl silicate oligomer and ethyl silicate oligomer. The weight-average molecular weight of the silicone resin is not particularly limited, but is preferably 200 to 10,000, and more preferably 400 to 5,000.

[0042] Examples of epoxy resins include bisphenol A type, bisphenol F type, phenol novolac type, polyfunctional tetrakis(hydroxyphenyl)ethane type or tris(hydroxyphenyl)methane type having many benzene rings, biphenyl type, triphenolmethane type, naphthalene type, ortho novolac type, dicyclopentadiene type, aminophenol type, alicyclic epoxy resins, silicone epoxy resins, and the like.

[0043] Examples of the reactive functional group of the thermoplastic resin having a reactive functional group include a hydroxyl group, a carboxyl group, an acid anhydride group, a sulfonic acid group, a phosphoric acid group, and a glycidyl group.

[0044] Among the binders listed above, acrylic resins, polyurethane resins, polyester resins, styrene resins, epoxy resins, vinyl acetate resins, vinyl chloride resins, silicone resins, and fluorine resins are preferred, and acrylic resins, polyurethane resins, and polyester resins are more preferred. The content of the binder in the conductive composition is preferably 30 to 99 wt %, more preferably 40 to 98 wt %, and even more preferably 60 to 97 wt %, based on the total solid content of the conductive composition.

[0045] The solid content of the conductive composition is preferably 2 to 50%, more preferably 2 to 40%, even more preferably 3 to 35%, and even more preferably 5 to 30%. If the solid content is outside the above range, the transparency and brightness of the conductive coating film tend to decrease. The solid content of the conductive composition can be adjusted by the amount of high-boiling point solvent and diluent blended, which will be described later.

[0046] <Optional ingredients> The conductive composition may contain, in addition to the conductive polymer, metal oxide, and binder, a carbon material, a high-boiling point solvent, a diluent, a crosslinking agent, a catalyst, a surfactant and / or a leveling agent, a water-soluble antioxidant, an antifoaming agent, a rheology control agent, a neutralizing agent, a thickener, an inorganic filler, and the like.

[0047] <Carbon materials> Examples of carbon materials include carbon nanotubes, graphene, fullerenes, and carbon nanofibers.

[0048] The type of carbon nanotube is not particularly limited, and carbon nanotubes manufactured by various known techniques such as arc discharge, laser evaporation, and chemical vapor deposition (CVD) can be appropriately selected and used. Single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, and mixtures containing these in any ratio can be used. Single-walled carbon nanotubes are preferred because of their excellent conductivity.

[0049] The length of the carbon nanotubes is preferably 0.1 to 2000 μm, more preferably 0.5 to 1000 μm, and even more preferably 0.5 to 500 μm. If the length exceeds 2000 μm, the carbon nanotubes tend to aggregate, break, or be destroyed. If the length is less than 0.1 μm, the formation of conductive paths tends to be insufficient.

[0050] The diameter of the carbon nanotubes is preferably 0.1 to 50 nm, more preferably 0.3 to 20 nm, and even more preferably 0.5 to 10 nm. If the diameter exceeds 50 nm, the conductivity tends to decrease. Carbon nanotubes with a diameter of less than 0.1 nm are difficult to produce. Furthermore, the carbon nanotubes may be aggregates of primary particles, and in this case, the average dispersed particle diameter of the aggregates is preferably 50 to 2000 nm, and more preferably 100 to 1500 nm.

[0051] The average dispersed particle size of graphene is preferably 50 to 4000 nm, more preferably 100 to 2000 nm.

[0052] The conductivity of the carbon material is preferably 0.5 to 5000 S / cm, more preferably 1 to 2000 S / cm. Within this range, the conductive coating film tends to have excellent conductivity.

[0053] The ratio of the total solid content of the conductive polymer and carbon material to the total solid content of the conductive composition is preferably 1% by weight or less, more preferably 0.05 to 0.75% by weight, and more preferably 0.1 to 0.5% by weight. By setting the ratio of the conductive polymer and carbon material in the conductive composition within this range, a conductive coating film that is both conductive and bright can be formed.

[0054] As long as the ratio of the total solid content of the conductive polymer and the carbon material to the total solid content of the conductive composition is 1% by weight or less, the blending amounts of the conductive polymer and the carbon material are not particularly limited. However, the solid content of the carbon material is preferably 0.1 to 10,000 parts by weight, more preferably 0.1 to 1,000 parts by weight, and even more preferably 0.5 to 100 parts by weight, per 100 parts by weight of the solid content of the conductive polymer.

[0055] The ratio of the solid content of the carbon material to the total solid content of the conductive composition is preferably 0.001 to 0.99% by weight, more preferably 0.01 to 0.95% by weight.

[0056] It is preferable to use a carbon material that has been dispersed in advance. Examples of a method for dispersing a carbon material include a method in which the carbon material is dispersed in a solvent in the presence of a dispersant. As the solvent for the dispersion treatment, a high-boiling point solvent or a diluent, which will be described later as a solvent optionally contained in the conductive composition, can be used, but water is preferred.

[0057] Examples of dispersants used to disperse carbon materials include cationic dispersants, anionic dispersants, amphoteric dispersants, nonionic dispersants, and polymeric dispersants. These may be used alone or in combination of two or more. Furthermore, dispersants with an HLB value of 12 or more are preferred, and those with an HLB value of 14 or more are more preferred. The HLB value in this specification can be calculated using the following formula: Griffin method: HLB value = [(molecular weight of hydrophilic portion) ÷ (total molecular weight)] × 20

[0058] Examples of cationic dispersants include alkylamine salts having an alkyl group with 8 to 22 carbon atoms, such as stearylamine acetate, and quaternary ammonium salts, such as lauryltrimethylammonium chloride and hexadecyltrimethylammonium bromide.

[0059] Examples of the anionic dispersant include sodium alkyl sulfates having 8 to 18 carbon atoms, such as sodium lauryl sulfate; polyoxyethylene alkyl ether sulfates having an alkyl group having 8 to 18 carbon atoms, such as sodium polyoxyethylene lauryl ether sulfate; alkylbenzenesulfonates having an alkyl group having 8 to 18 carbon atoms, such as sodium deoxycholate and sodium dodecylbenzenesulfonate; fatty acid salts; and naphthalenesulfonate-formalin condensates, such as the sodium salt of β-naphthalenesulfonate-formalin condensate.

[0060] Examples of amphoteric dispersants include alkylbetaines having an alkyl group with 8 to 22 carbon atoms, and alkylamine oxides having an alkyl group with 8 to 18 carbon atoms.

[0061] Examples of nonionic dispersants include polyoxyethylene alkyl ethers having an alkyl group with 1 to 20 carbon atoms, block copolymers composed of ethylene oxide and propylene oxide, alkylphenol polyethylene glycol ethers having an alkyl group with 1 to 20 carbon atoms, polyoxyalkylene derivatives such as polycarboxylate ethers having an alkylene group with 2 to 4 carbon atoms, and sorbitan fatty acid esters such as sorbitan tristearate.

[0062] Examples of polymeric dispersants include polyvinylpyrrolidone, polyvinyl alcohol, hydroxycellulose, hydroxyalkylcellulose having an alkyl group with 1 to 8 carbon atoms, cellulose derivatives such as carboxymethyl cellulose and carboxypropyl cellulose, starch, gelatin, acrylic copolymers, polycarboxylic acids and their derivatives. Polymeric sulfonic acids include polystyrene sulfonic acid or its salts, and fluorine-based polymers containing sulfonic acid. Fluorine-based polymers containing sulfonic acid are preferred, with perfluorosulfonic acid polymers and partially fluorinated sulfonic acid polymers being more preferred. Specific examples include Nafion (NAFION®, manufactured by DuPont) and Aquivion (AQUIVION®, manufactured by Solvay Specialty Polymers).

[0063] From the viewpoint of achieving both dispersibility and transparency, the amount of dispersant used is preferably 0.01 to 100 parts by weight, more preferably 0.2 to 40 parts by weight, and even more preferably 0.5 to 10 parts by weight, per part by weight of the carbon material.

[0064] The carbon material can be dispersed using, for example, a vibration mill, planetary mill, ball mill, bead mill, sand mill, jet mill, roll mill, homogenizer, ultrasonic homogenizer, high-pressure homogenizer, ultrasonic device, etc. The pH condition during dispersion of the carbon material is preferably 0.5 to 9.0. The temperature condition is preferably 0 to 40°C. The dispersion time is preferably 0.02 to 2 hours.

[0065] Prior to the dispersion treatment, the carbon material may be subjected to a high-speed stirring treatment as a pretreatment. The high-speed stirring treatment is a dispersion treatment under conditions that are relatively less intense than dispersion treatments using an ultrasonic homogenizer or the like, and the high-speed rotation of the stirring body has the effect of loosening the agglomeration of the carbon material. By performing the high-speed stirring treatment prior to the dispersion treatment, the dispersion treatment of the carbon material can be carried out more efficiently. Furthermore, if necessary, after the dispersion treatment of the carbon material, agglomerates remaining in the dispersion liquid may be removed by centrifugation or filtration.

[0066] <High boiling point solvents, diluents> A high-boiling point solvent refers to a solvent with a boiling point of 110°C or higher, preferably 130°C or higher, and more preferably 150°C or higher. The upper limit of the boiling point is generally 300°C. By blending a high-boiling point solvent, the conductivity of the conductive composition can be improved. Specific examples of high-boiling point solvents include amide compounds such as N-methylformamide, N,N-dimethylformamide, γ-butyrolactone, and N-methylpyrrolidone; hydroxyl group-containing compounds such as ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, catechol, cyclohexanediol, cyclohexanedimethanol, glycerin, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, polyglycerin, and phenol analogues; carbonyl group-containing compounds such as isophorone, propylene carbonate, cyclohexanone, acetylacetone, ethyl acetoacetate, methyl orthoacetate, and ethyl orthoformate; and compounds having a sulfo group such as dimethyl sulfoxide. The amount of the high-boiling point solvent to be blended may be any amount that can achieve the solid content of the conductive composition described above, and is preferably 0 to 80% by weight, more preferably 2 to 60% by weight, and even more preferably 2 to 40% by weight, of the conductive composition.

[0067] The diluent is not particularly limited, and examples thereof include water; alcohols such as methanol, ethanol, 2-propanol, and 1-propanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol diethyl ether, and diethylene glycol dimethyl ether; glycol ether acetates such as ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate; propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, propylene glycol dimethyl ether, and propylene glycol monomethyl ether. Examples of suitable diluents include propylene glycol ethers such as propylene glycol diethyl ether; propylene glycol ether acetates such as propylene glycol monomethyl ether acetate; ethers such as diethyl ether, diisopropyl ether, methyl t-butyl ether, and tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; hydrocarbons such as toluene, xylene (o-, m-, or p-xylene), hexane, and heptane; esters such as ethyl acetate and butyl acetate; halogens, acetonitrile, mixed solvents of water and these organic solvents (hydrous organic solvents), and mixed solvents of two or more organic solvents. Among these, diluents with a boiling point of 110°C or less are preferred, with water, alcohols, and glycol ethers being more preferred. Mixed solvents of water and hydrophilic organic solvents may also be used. It is preferable that the diluent not remain in the conductive coating film formed using the conductive composition. The amount of diluent to be added may be any amount that allows the aforementioned solid content of the conductive composition to be achieved, and is preferably 1 to 99.9 wt % and more preferably 10 to 99 wt % of the conductive composition. The amount of water to be added is preferably 20 to 100 wt %, more preferably 50 to 100 wt %, even more preferably 75 to 100 wt %, and particularly preferably 90 to 100 wt % of the liquid components of the conductive composition.

[0068] The high-boiling solvent and diluent may be used in combination. When the high-boiling solvent and diluent are used in combination, the amount of the diluent used is preferably 100 to 100,000 parts by weight, more preferably 500 to 50,000 parts by weight, and even more preferably 2,200 to 3,000 parts by weight, per 100 parts by weight of the high-boiling solvent.

[0069] <Crosslinking agent> The crosslinking agent is not particularly limited, but examples thereof include melamine-based, carbodiimide-based, oxazoline-based, epoxy-based, isocyanate-based, and acrylate-based crosslinking agents. When the conductive composition contains a crosslinking agent, the content thereof is not particularly limited, but is preferably 30% by weight or less, and more preferably 20% by weight or less, of the conductive composition. When the conductive composition contains a thermosetting binder and a crosslinking agent, the catalyst for crosslinking the thermosetting binder is not particularly limited, and examples thereof include a photopolymerization initiator and a thermal polymerization initiator.

[0070] <Surfactants, leveling agents> By blending a surfactant and / or a leveling agent into the conductive composition, the leveling properties of the conductive composition can be improved, and a uniform conductive coating film can be formed.

[0071] The surfactant is not particularly limited as long as it has the effect of improving leveling properties, and examples thereof include siloxane compounds such as polyether-modified polydimethylsiloxane, polyether-modified siloxane, polyetherester-modified hydroxyl group-containing polydimethylsiloxane, polyether-modified acrylic group-containing polydimethylsiloxane, polyester-modified acrylic group-containing polydimethylsiloxane, perfluoropolydimethylsiloxane, perfluoropolyether-modified polydimethylsiloxane, and perfluoropolyester-modified polydimethylsiloxane; fluorine-based compounds such as perfluoroalkylcarboxylic acids; polyether-based compounds such as polyoxyethylene alkylphenyl ether; carboxylic acids such as coconut oil fatty acid amine salts; ester-based compounds such as phosphate esters, alkyl ether sulfates, sorbitan fatty acid esters, sulfonate esters, and succinate esters; sulfonate compounds such as alkylarylsulfonic acid amine salts and dioctyl sodium sulfosuccinate; phosphate compounds such as sodium lauryl phosphate; amide compounds such as coconut oil fatty acid ethanolamide; and acrylic compounds.

[0072] Examples of the leveling agent include siloxane-based compounds such as polyether-modified polydimethylsiloxane, polyether-modified siloxane, polyetherester-modified hydroxyl group-containing polydimethylsiloxane, polyether-modified acrylic group-containing polydimethylsiloxane, polyester-modified acrylic group-containing polydimethylsiloxane, perfluoropolydimethylsiloxane, perfluoropolyether-modified polydimethylsiloxane, and perfluoropolyester-modified polydimethylsiloxane; fluorine-based compounds such as perfluoroalkylcarboxylic acid and perfluoroalkylpolyoxyethyleneethanol; Examples of suitable carboxylic acids include polyether compounds such as polyoxyethylene alkylphenyl ether, propylene oxide polymers, and ethylene oxide polymers; carboxylic acids such as coconut oil fatty acid amine salts and gum rosin; ester compounds such as castor oil sulfates, phosphate esters, alkyl ether sulfates, sorbitan fatty acid esters, sulfonate esters, and succinate esters; sulfonate compounds such as alkylarylsulfonic acid amine salts and dioctyl sodium sulfosuccinate; phosphate compounds such as sodium lauryl phosphate; amide compounds such as coconut oil fatty acid ethanolamide; and acrylic compounds.

[0073] When the conductive composition contains a surfactant and / or a leveling agent, the proportion of the solid content of the surfactant and / or leveling agent relative to the total solid content of the conductive composition is preferably 0.01 to 20% by weight, more preferably 0.1 to 10% by weight.

[0074] <Water-soluble antioxidant> By blending a water-soluble antioxidant into the conductive composition, the heat resistance and moist heat resistance of the conductive coating film can be improved. Examples of the water-soluble antioxidant include reducing water-soluble antioxidants and non-reducing water-soluble antioxidants. When the conductive composition contains a water-soluble antioxidant, its content in the conductive composition is preferably 1 to 20 wt %, more preferably 5 to 10 wt %.

[0075] The conductive composition can be obtained by mixing a conductive polymer, a metal oxide, a binder, and, if necessary, any optional components in any order.

[0076] <<Conductive coating>> The conductive composition is applied to at least one surface of a substrate, and then heat-treated to obtain a conductive coating film.

[0077] The surface resistivity of the conductive coating is 1.0 x 10 1 ~1.0×10 9 Ω / □ is preferred, 1.0×10 2 ~1.0×10 8 Ω / □ is more preferable, 1.0×10 3 ~1.0×10 7 More preferably, it is Ω / □. The surface resistivity is a value measured by the method described in the examples for a conductive coating film having a thickness of 4.0 to 15 μm formed on a substrate.

[0078] The lightness of the conductive coating film is preferably 70 to 99.9, more preferably 73 to 99.9, and even more preferably 80 to 99.9. The lightness of the conductive coating film can be calculated by placing a laminate consisting of a substrate and a conductive coating film with a thickness of 4.0 to 15 μm formed on the substrate on a ceramic standard white plate and measuring the lightness L* with a color difference meter, and subtracting the L* of the substrate film alone from the measured lightness L*. The color difference meter that can be used is the Color Reader CR-20 manufactured by Konica Minolta Sensing, Inc.

[0079] The thickness of the conductive coating film is preferably 0.1 to 1000 μm, more preferably 0.1 to 100 μm, and even more preferably 0.1 to 20 μm. The thickness of the conductive coating film is calculated from the solid content of the conductive composition and the amount applied to the substrate.

[0080] Examples of materials for the substrate include glass, polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate, and modified polyester, polyolefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, polystyrene resin, and cyclic olefin resin, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin, polysulfone (PSF) resin, polyethersulfone (PES) resin, polycarbonate (PC) resin, polyamide resin, polyimide resin, acrylic resin, triacetyl cellulose (TAC) resin, and metals such as copper and aluminum. The substrate is preferably in the form of a film, and the thickness of the substrate film is preferably 10 to 10,000 μm, and more preferably 25 to 5,000 μm. The total light transmittance of the substrate film is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

[0081] The conductive coating film may be formed by directly applying the conductive composition to the substrate, or by applying the conductive composition onto another layer, such as a primer layer, that is previously provided on the substrate. The method for applying the conductive composition to at least one surface of the substrate is not particularly limited and any known method may be used, such as roll coating, bar coating, dip coating, spin coating, casting, die coating, blade coating, bar coating, gravure coating, curtain coating, spray coating, doctor coating, slit coating, relief (letterpress) printing, stencil (screen) printing, lithographic (offset) printing, intaglio (gravure) printing, spray printing, inkjet printing, or pad printing.

[0082] Before applying the conductive composition to at least one surface of the substrate, the surface of the substrate may be subjected to a surface treatment, such as a corona treatment, a plasma treatment, an itro treatment, or a flame treatment, if necessary.

[0083] The heat treatment after applying the conductive composition to at least one surface of the substrate can be carried out using, for example, a fan oven, an infrared oven, a vacuum oven, etc. When the conductive composition contains volatile components such as a high-boiling point solvent or a diluent, the volatile components are preferably removed by the heat treatment. The heating temperature is preferably 60 to 200°C, more preferably 80 to 180°C. The heating time is preferably 0.1 to 20 minutes, more preferably 1 to 5 minutes.

[0084] The conductive coating film is suitable for use in applications where conductivity or antistatic properties and design are required, such as clean room interior materials, automobile interior materials, surface protection films, transparent conductive films, and electrostatic coating primers. [Example]

[0085] The present invention will be described below with reference to examples, but is not limited to the following examples. Hereinafter, "parts" and "%" mean "parts by weight" and "% by weight", respectively, unless otherwise specified.

[0086] (1) Materials used (1-1) Conductive polymer PEDOT dispersion 1 (Heraeus, Clevios PH1000, solid content 1.1 wt%, particle size 4.7 nm, conductivity 824 S / cm, aqueous dispersion)

[0087] (1-2) Metal oxides Zinc oxide (Tokushiki Corporation, 9406ZO, solid content 33% by weight, particle size 280 nm, water dispersion) Titanium oxide (Tokushiki Corporation, 9340TO, solid content 32% by weight, particle size 700 nm, water dispersion) Tin oxide (Tokushiki Corporation, 9747SN, solid content 22% by weight, particle size 180 nm, water dispersion) Cerium oxide (CeO2) (Daiichi Kigenso Kagaku Kogyo, CESL-30N, solid content 30% by weight, particle size 10 nm, water dispersion)

[0088] (1-3) Carbon materials Carbon nanotube dispersion 1 (prepared in Production Example 1, solid content 0.7% by weight, solid content excluding dispersant 0.1%, particle diameter 312 nm, conductivity 153 S / cm, 30% by weight ethanol aqueous solution dispersion)

[0089] (1-4) Binder Acrylic resin (Nikazole RX-7004E, manufactured by Nippon Carbide Corporation, solid content 35%, water dispersion) Polyester resin (Go-o Chemical Co., Ltd., Pluscoat RZ-105, solids content 30%, water dispersion) Polyurethane resin (Superflex 200, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., solid content 35%, water dispersion)

[0090] (1-5) High-boiling point solvent Ethylene glycol

[0091] (1-6) Diluent ·water ·ethanol

[0092] (2) Production of Carbon Nanotube Dispersion 1 (Production Example 1) 0.1 parts by weight of carbon nanotubes (ZEON Nano Technology Co., Ltd., ZEONANO SG101) with an average length of 300 μm and a diameter of approximately 4 nm, 0.6 parts by weight of a non-ionic dispersant (BASF, Pluronic F108, HLB: 24 or higher) as a dispersant, 30 parts by weight of ethanol, and 70 parts by weight of pure water were placed in a glass beaker, and the mixture was dispersed for 30 minutes using an ultrasonic homogenizer (Hielscher, product name "HP50H") at 50 W and a frequency of 30 kHz, to obtain carbon nanotube dispersion 1 with a solid content of 0.7 wt%.

[0093] (3) Production of Conductive Composition and Formation of Conductive Coating Film (Examples 1 to 14, Comparative Examples 1 to 7) Conductive compositions were prepared by mixing the components in the weights listed in Tables 1 and 2. The values ​​for the conductive polymer, carbon material, metal oxide, and binder listed in Tables 1 and 2 represent the ratio (wt%) of the solid content. A mixed solvent containing a high-boiling-point solvent and a diluent was used in the amounts listed in Tables 1 and 2, and adjusted to the solid content concentration (wt%) listed in Tables 1 and 2. The resulting conductive composition was applied to one side of a polyester resin substrate film (Lumirror T60, manufactured by Toray Industries, Inc.) by bar coating, and then dried at 120°C for 5 minutes using an air dryer to form a conductive coating film on the substrate film. The thickness of the conductive coating film was adjusted to the thickness listed in Tables 1 and 2 by selecting the grit size of the bar coater.

[0094] The lightness L* and surface resistivity of the obtained conductive coating film were evaluated by the evaluation methods described below. The results are shown in Tables 1 and 2.

[0095] [Table 1] [Table 2]

[0096] In Comparative Example 1, which used a conductive composition containing no metal oxide, the surface resistivity of the conductive coating film was high. In Comparative Example 2, the amount of conductive polymer was increased, resulting in a lower surface resistivity than in Comparative Example 1, but also a lower brightness. In Comparative Example 3, which did not contain a conductive polymer but did contain a carbon material, the surface resistivity was low, but the brightness was also low. In Comparative Examples 4 to 7, which did not contain a conductive polymer, the surface resistivity was high. In Examples 1 to 14, the conductive coating films had high brightness and low surface resistivity.

[0097] (4) Evaluation method for conductive coating film (4-1) Brightness The laminate consisting of the base film and the conductive coating film was placed on a ceramic standard white plate, and the lightness L* was measured using a color difference meter (Color Reader CR-20 manufactured by Konica Minolta Sensing, Inc.) The L* of the conductive coating film was calculated by subtracting the L* of the base film alone from the L* of the laminate.

[0098] (4-2)Surface resistivity The surface resistivity of the conductive coating film was measured using a UA probe of a resistivity meter (Mitsubishi Chemical Corporation, Hiresta UP (MCP-HT450 model)) and an ESP probe of a resistivity meter (Mitsubishi Chemical Corporation, Loresta GP (MCP-T600 model)). The probe was pressed against the surface of the conductive coating film, and the surface resistivity was determined when an applied voltage of 10 V was maintained for 10 seconds.

[0099] The present invention may include, for example, the following aspects. <1> A conductive composition comprising a conductive polymer, a metal oxide and a binder, wherein the proportion of the solid content of the conductive polymer relative to the total solid content is 1% by weight or less. <2> Item 2. The conductive composition according to item 1, further comprising a carbon material, wherein the ratio of the total solid content of the conductive polymer and the carbon material to the total solid content is 1 wt % or less. <3> Item 3. The conductive composition according to item 2, wherein the solid content of the metal oxide is 200 to 1000 parts by weight per 100 parts by weight of the total solid content of the conductive polymer and the carbon material. <4> Item 4. The conductive composition according to any one of Items 1 to 3, wherein the conductive polymer is one or more selected from the group consisting of polythiophene, polypyrrole, and polyaniline. <5> 5. The conductive composition according to any one of items 1 to 4, wherein the metal oxide is one or more selected from the group consisting of zinc oxide, titanium oxide, phosphate-doped tin, antimony-doped tin, and cerium oxide. <6> Item 6. The conductive composition according to any one of Items 1 to 5, wherein the binder is at least one selected from the group consisting of an acrylic resin, a polyurethane resin, a polyester resin, a styrene resin, an epoxy resin, a vinyl acetate resin, a vinyl chloride resin, a silicone resin, and a fluorine-based resin. <7> Item 3. The conductive composition according to item 2, wherein the carbon material is one or more selected from the group consisting of carbon nanotubes, graphene, and fullerenes. <8> Item 8. The conductive composition according to any one of items 1 to 7, wherein the conductive polymer has an average dispersed particle size of 0.1 to 1000 nm. <9> Item 9. The conductive composition according to any one of items 1 to 8, wherein the metal oxide has an average dispersed particle size of 1 to 10,000 nm. <10> Item 10. The conductive composition according to any one of items 1 to 9, having a solid content of 2 to 50%.

Claims

1. A conductive composition comprising a conductive polymer, a metal oxide and a binder, wherein the proportion of the solid content of the conductive polymer relative to the total solid content is 1% by weight or less.

2. 2. The conductive composition according to claim 1, further comprising a carbon material, wherein the ratio of the total solid content of the conductive polymer and the carbon material to the total solid content is 1% by weight or less.

3. 3. The conductive composition according to claim 2, wherein the solid content of the metal oxide is 200 to 1000 parts by weight per 100 parts by weight of the total solid content of the conductive polymer and the carbon material.

4. 3. The conductive composition according to claim 1, wherein the conductive polymer is at least one selected from the group consisting of polythiophene, polypyrrole, and polyaniline.

5. 3. The conductive composition according to claim 1, wherein the metal oxide is at least one selected from the group consisting of zinc oxide, titanium oxide, phosphorus-doped tin oxide, antimony-doped tin oxide, and cerium oxide.

6. 3. The conductive composition according to claim 1, wherein the binder is at least one selected from the group consisting of an acrylic resin, a polyurethane resin, a polyester resin, a styrene resin, an epoxy resin, a vinyl acetate resin, a vinyl chloride resin, a silicone resin, and a fluorine-based resin.

7. The conductive composition according to claim 2 , wherein the carbon material is one or more selected from the group consisting of carbon nanotubes, graphene, and fullerenes.

8. 3. The conductive composition according to claim 1, wherein the conductive polymer has an average dispersed particle size of 0.1 to 1000 nm.

9. 3. The conductive composition according to claim 1, wherein the average dispersed particle size of the metal oxide is 1 to 10,000 nm.

10. 3. The conductive composition according to claim 1, wherein the solid content is 2 to 50%.

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