JP2013163328A - Manufacturing method for conductive board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a conductive board by which a conductive board having superior transparency and conductivity can be manufactured with favorable productivity.SOLUTION: In a manufacturing method for a conductive board having a substrate and a conductive layer, a laminated layer is formed on one surface of the substrate in a step of applying a coating liquid containing a surfactant to one surface of the substrate and a step of drying the coating liquid; and a conductive layer is formed on the laminated layer in a step of applying an emulsion coating liquid (hereinafter "coating liquid 2") containing metal particulates to the laminated film and a step of drying the emulsion coating liquid. The surfactant and the coating liquid 2 meet the following condition 1 or 2. Condition 1: An HLB value of the surfactant is 10 or larger and 20 or smaller and the coating liquid 2 is a W/O-type emulsion coating liquid. Condition 2: An HLB value of the surfactant is 3 or larger and smaller than 10 and the coating liquid 2 is the O/W-type emulsion coating liquid.

Description

  The present invention relates to a method for producing a conductive substrate excellent in productivity, transparency, and conductivity.

  In recent years, conductive substrates have been used in various building materials and equipment as building materials and circuit materials, and are used for applications such as electromagnetic shielding substrates, touch panels, and solar cells.

  The electromagnetic shielding substrate is used for the purpose of suppressing various electromagnetic waves radiated from electronic devices such as home appliances, mobile phones, personal computers, and televisions. Since these electronic devices are used at a relatively short distance and in some cases for a long time, an electromagnetic wave shielding substrate that suppresses these electromagnetic waves is required and has been intensively studied.

  In general, since a conductive substrate is formed by sputtering or vacuum deposition, a vacuum apparatus is required, the film formation speed is slow, mass productivity is poor, film formation over a large area is difficult, and high cost. There is a drawback of becoming. The conductive film also has a problem that indium oxide, which is a conductive metal oxide, is expensive.

  As a technique for improving transparency without using a sputtering method as in Patent Document 1 and Patent Document 2, as a conductive film, a copper foil layer is laminated on the surface of a transparent substrate by electroless plating, and a photolithographic method is used. Although a method for forming a very fine pattern with high accuracy by etching after forming a resist pattern is disclosed, most of the copper foil layer formed by plating is removed by etching. Therefore, there is a problem that the manufacturing cost becomes high, for example, the waste of the copper material is large and the waste liquid treatment is also expensive. In addition, in order to increase the area, cost is required in terms of capital investment such as an increase in the size of the etching apparatus.

JP-A-10-163673 Japanese Patent Laid-Open No. 5-16281

  The objective of this invention is providing the manufacturing method of the electroconductive board | substrate excellent in productivity, transparency, and electroconductivity.

The manufacturing method of the electroconductive board | substrate of this invention is as follows.
1) A method of manufacturing a conductive substrate having a substrate and a conductive layer,
A laminated film is formed on one side of the substrate by a step of applying a coating liquid containing a surfactant and a step of drying.
A conductive layer is formed by applying an emulsion coating liquid containing metal fine particles (hereinafter referred to as coating liquid 2) on the laminated film and a drying process.
The said surfactant and the coating liquid 2 satisfy | fill the following conditions 1 or 2, The manufacturing method of the electroconductive board | substrate characterized by the above-mentioned.

    Condition 1: The surfactant has an HLB value of 10 or more and 20 or less, and the coating liquid 2 is a W / O emulsion coating liquid.

Condition 2: The surfactant has an HLB value of 3 to less than 10, and the coating liquid 2 is an O / W emulsion coating liquid.
2) The method for producing a conductive substrate according to 1) above, wherein a freezing point temperature of the surfactant is 35 ° C. or higher and 100 ° C. or lower.
3) The method for producing a conductive substrate according to 1) or 2) above, wherein a surface free energy of the laminated film is 50 mN / m or more and 80 mN / m or less.
4) The method for producing a conductive substrate according to any one of 1) to 3) above, wherein the surfactant is soluble in an organic solvent and / or water in the coating liquid 2.
5) The method for producing a conductive substrate according to any one of 1) to 4) above, wherein the temperature of the laminated film when the coating liquid 2 is applied is 5 ° C. or higher and lower than 35 ° C.
6) The method for producing a conductive substrate according to any one of 1) to 5) above, wherein the surface specific resistance of the conductive layer is 30 Ω / □ or less.

  ADVANTAGE OF THE INVENTION According to this invention, the simple manufacturing method of the electroconductive board | substrate excellent in productivity, transparency, and electroconductivity can be provided. In addition, since the conductive substrate obtained by the production method of the present invention can have a high level of conductivity, the conductive substrate is suitably used, for example, for electromagnetic wave shielding and transparent sheet heating elements. be able to.

  In the present invention, a laminated film is formed on a single side of a substrate by a step of applying a coating liquid containing a surfactant (hereinafter referred to as coating liquid 1) and a step of drying, and metal fine particles are formed on the laminated film. A conductive layer can be formed by the process of apply | coating the emulsion coating liquid containing this (it is hereafter set as the coating liquid 2), and the process of drying, and can be set as a conductive substrate. By using this method, the inventors have investigated that the above-mentioned problems can be solved at once by using a conductive substrate.

  In the present invention, when the HLB value of the surfactant of the coating liquid 1 is 10 or more and 20 or less, the coating liquid 2 is a W / O emulsion solution, or the surfactant of the coating liquid 1 When the HLB value is 3 or more and less than 10, it is important that the coating liquid 2 has an O / W emulsion solution condition. Only under these conditions, the conductive substrate of the present invention can be obtained. Become.

  The coating liquid 1 of the present invention is preferably a coating liquid containing a surfactant. By using the surfactant, it becomes possible to adjust the degree of hydrophobicity and hydrophilicity of the surface of the laminated film of the present invention. By making the HLB value 10 or more and 20 or less, the laminated film can be made hydrophilic. Moreover, it becomes possible to make it lipophilic by making it 3 or more and less than 10.

  Here, the HLB value of the surfactant is an abbreviation for “Hydrophile-Lypophile Balanze”, and is a parameter representing the balance between hydrophilicity and lipophilicity. The numerical value is determined so that the hydrophilicity decreases as the HLB value increases and the lipophilicity increases as the HLB value decreases. There are several methods for determining the HLB value, but in the present invention, according to the Karabinos phenol titration method described on page 324 of the surfactant manual (edited by Nishiichiro et al., Published by Sangyo Tosho Co., Ltd., 1960). The method was adopted. This method is generally referred to as a haze number measurement method in the surfactant industry, and its principle is milky white when a surfactant is titrated with a phenol solution. This is a method of calculating the HLB value from the cloudy number).

  The coating liquid 2 of the present invention preferably has good wettability with a continuous phase of a coating liquid composed of a specific emulsion and good wettability with a discontinuous phase droplet. Further, if the coating liquid 2 is a W / O (water in oil) type, the laminated film does not have good wettability with an organic solvent that is a continuous phase, and has good wettability with an aqueous solvent that is a discontinuous phase. For this purpose, the laminated film needs to be hydrophilic. Conversely, if the coating liquid 2 is an O / W (oil in water) type emulsion, the laminated film is a continuous phase. It is preferable that the wettability with the aqueous solvent and the organic solvent which is a discontinuous phase is not good, and the laminated film needs to be lipophilic.

  Here, the emulsion which is the coating liquid 2 indicates a dispersion solvent in which both the solute and the solvent are liquids. In the above W / O type emulsion, the continuous phase is an organic solvent, and the discontinuous phase is an aqueous solvent. In the above O / W emulsion, the continuous phase is an aqueous solvent and the discontinuous phase is an organic solvent.

  Moreover, it is preferable that the metal fine particles in the coating liquid 2 of the present invention are dispersed in a continuous phase, and by using a coating liquid in which metal fine particles are dispersed in the continuous phase, a conductive substrate having excellent conductivity is produced. Can be obtained.

  Examples of the method for adjusting the metal fine particles include a chemical method in which metal ions are reduced to metal atoms in a liquid layer and grown into nanoparticles through atomic clusters, or bulk metal is evaporated in an inert gas. Physics of trapping metal in fine particles with a cold trap, physics of breaking metal thin film by heating metal thin film obtained by vacuum deposition on polymer thin film, and dispersing metal nanoparticles in polymer in solid state Or the like can be used.

  The metal component of the metal fine particles is not particularly limited as long as it exhibits conductivity. For example, gold, silver, platinum, copper, nickel, palladium, rhodium, ruthenium, bismuth, cobalt, iron, aluminum, zinc, tin The metal component to be used may be one type or a combination of two or more types. Here, the type of metal component is determined by the element of the metal. For example, when two coppers having different particle diameters exist, these are the same metal component and are two types of metal components.

  In the coating liquid 2 of the present invention, various additives such as a dispersant, a surface tension adjusting agent, a viscosity adjusting agent, a pH adjusting agent, a preservative, a chelating agent, and an antifoaming agent are provided as long as the effects of the present invention are not impaired. Further, an antioxidant or the like may be included. Further, in order to improve the adhesion to the substrate, the coating liquid 2 may contain a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, or a known resin. These various additives may be contained in either the continuous phase or the discontinuous phase, without any problem even if they are contained in either the continuous phase or the discontinuous phase of the emulsion.

  The laminated film of the present invention preferably contains a surfactant, and the surfactant is mainly composed of a surfactant having a freezing point temperature of 35 ° C. or higher and 100 ° C. or lower. The freezing point temperature of the surfactant is more preferably 35 ° C. or more and 60 ° C. or less, and further preferably 40 ° C. or more and 50 ° C. or less. Here, the freezing point temperature indicates a temperature at which the liquid solidifies and solidifies, and when there is no hysteresis, it coincides with the melting point (temperature at which the solid melts).

  When the freezing point temperature of the surfactant as the main component of the laminated film is less than 35 ° C., the application process is usually normal temperature, and when the laminated film is formed after applying the coating liquid 1 to the substrate, the laminated film When the surface is sticky and the production liquid is coated with the coating liquid 1 and dried, and there is a step in which the laminated film side comes into contact with the roll while the coating liquid 2 is applied, blocking with the roll occurs, and the laminated film becomes a roll. Transferring may cause problems such as deterioration of productivity and coating quality such as line contamination and coating unevenness.

  If the freezing point temperature of the surfactant of the present invention is 35 ° C. or higher, problems such as transfer to other materials do not occur, so that the coating quality is good, which is preferable.

  The surfactant having a freezing point temperature in the laminated film of 35 ° C. or more and 100 ° C. or less contains the most surfactant in a mass ratio of the freezing point temperature of 35 ° C. or more and 100 ° C. or less in 100% by mass of the whole laminated film. Means. Preferably, the surfactant having a freezing point temperature of 35 ° C. or more and 100 ° C. or less is 50% by mass or more and 100% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and more preferably 100% by mass in total. Is 50 mass% or more and 80 mass% or less.

  The laminated film is not particularly limited as long as the surfactant having a freezing point temperature of 35 ° C. or higher and 100 ° C. or lower is a main component, and organic and inorganic polymers, monomers, oligomers, organic and inorganic particles, In addition, a component composed of a surfactant and an additive different from the surfactant as the main component of the laminated film may be included.

  The surfactant of the coating liquid 1 of the present invention is not particularly limited, and a known anionic surfactant, cationic surfactant, nonionic surfactant, amphoteric surfactant, or the like may be used. In particular, a nonionic surfactant is preferable. Here, the nonionic surfactant is a “surfactant having a hydrophilic group that does not ionize when dissolved in water”. Among such nonionic surfactants, nonionic surfactants having an ethylene oxide group as a hydrophilic group are preferable. As the surfactant, the same type of surfactant may be used singly or in combination of two or more types, or different types of surfactant may be used in combination of one or more types. .

  Here, the surfactant is an international surfactant conference in 1972, “Surfactant has a hydrophilic group and a hydrophobic group in the molecule and is dissolved or dispersed in a liquid (solvent). , A compound that selectively (preferentially) adsorbs to the interface and has practical properties. The surfactant referred to in the present invention also follows this definition. The surfactant according to this definition corresponds to a compound having a hydrophilic group and a hydrophobic group.

  Specific examples of the anionic surfactant include higher fatty acid salts such as sodium laurate, sodium stearylate, and sodium oleate, sodium dodecyl sulfate, sodium lauryl sulfate, sodium cetyl sulfate, sodium stearyl sulfate, and oleyl sulfate. Alkyl sulfates such as sodium, alkyl sulfonates such as sodium octyl alcohol sulfate, higher alcohol sulfates such as sodium lauryl alcohol sulfate, sodium lauryl benzene sulfonate, sodium cetyl benzene sulfonate, sodium stearyl benzene sulfonate, Alkyl naphthalene sulfonates such as sodium isopropyl naphthalene sulfonate, sodium dialkyl ether disulfonate Alkyldiphenyl ether sulfonates such as sodium lauryl phosphate, alkyl phosphate esters such as sodium lauryl phosphate, sodium stearyl phosphate, polyoxyethylene oxide adducts of sodium lauryl ether sulfate, polyoxyethylene oxide adducts of ammonium lauryl ether sulfate, etc. Polyoxyethylene oxide adducts of alkyl ether sulfates, polyoxyethylene oxide adducts of alkylphenyl ether sulfates such as polyoxyethylene oxide adducts of sodium nonylphenyl ether sulfate, sodium di-2-ethylhexylsulfosuccinate, Sodium di-octylsulfosuccinate, sodium oleic acid amide sulfosuccinate, polyoxyethylene (POE) lauryl sodium sulfosuccinate Um, and alkyl sulfosuccinate salts such as sulfosuccinate sodium lauryl like.

  Specific examples of the cationic surfactant include quaternary ammonium salts such as cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, laurylpyridinium chloride, laurylpyridinium bromide, Examples include pyridinium salts such as cetylpyridinium chloride, imidazolium salts such as 2-stearyl-hydroxyethyl-2-imidazoline derivatives, N, N-diethyl-stearamide-methylamine hydrochloride, amine salts of polyoxyethylene stearylamines, etc. be able to.

  Specific examples of nonionic surfactants include polyoxyethylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene 2-ethylhexyl. Ether, polyoxyethylene nonyl ether, polyoxyethylene isodecyl ether, polyoxyethylene synthetic alcohol ether, polyoxyethylene secondary alcohol ether, polyoxyethylene tridecyl ether, polyoxyethylene long chain alkyl ether, polyoxyethylene octylphenyl ether , Polyoxyethylene nonyl phenyl ether, polyoxyethylene decyl phenyl ether, polyoxyethylene styrene Phenyl ether, polyoxyethylene phenyl ether, polyoxyethylene benzyl ether, polyoxyethylene β-naphthyl ether, polyoxyethylene bisphenol F ether, polyoxyethylene laurylamine, polyoxyethylene beef tallow amine, polyoxyethylene stearylamine, poly Oxyethylene oleylamine, polyoxyethylene beef tallow propylene diamine, polyoxyethylene metaxylene diamine, polyoxyethylene oleyl amide, polyoxyethylene stearyl amide, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene mono tallow oleate , Polyoxyethylene monooleate, polyoxyethylene castor oil, polyoxyethylene castor oil ether , Polyoxyethylene hydrogenated castor oil, polyoxyethylene distearate, polyoxyethylene rosin ester, polyoxyethylene wool grease ether, polyoxyethylene lanolin ether, polyoxyethylene lanolin alcohol ether, polyoxyethylene pentaerythritol dioleate, Polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitol tetraoleate, polyoxyethylene glyceryl isostearate, polyoxyalkylene branched decyl ether, polyoxyalkylene tridecyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene lauryl ether, Polyoxyethylene alkyl ether, polyoxyethylene oleyl cetyl ether, polyoxyethylene Rubitan fatty acid ester, polyoxyethylene glyceryl oleate, polyoxyethylene glyceryl isostearate, polyoxyalkylene 2-ethylhexyl ether, polyoxyalkylene nonyl ether, polyoxyethylene polycyclic phenyl ether, polyoxyethylene aryl ether, polyoxyethylene Examples thereof include milphenyl ether, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene alkylamine ether, and the like.

  Examples of amphoteric surfactants include imidazoline-based amphoteric surfactants such as 2-undecyl-N, N, N- (hydroxyethylcarboxylmethyl) -2-imidazoline sodium, lauryldimethylaminoacetic acid betaine, alkylbetaine, sulfobetaine. And betaine surfactants such as amide betaine. In addition, a resin component having surface activity may be added. For example, hydrophilic properties such as polyvinyl alcohol, (meth) acrylic acid / (meth) alkyl acrylate copolymer, (meth) acrylic acid / styrene copolymer, etc. Monomer and hydrophobic monomer copolymer, hydrophobic segment is composed of aliphatic polyester, polyamino acid, poly (epsilon-caprolactone), polylactic acid or polyglycolic acid, and any of those copolymers or analogs And a block copolymer having a hydrophilic segment made of polyethylene glycol and polypropylene glycol.

  The surface free energy of the laminated film of the present invention is preferably 50 mN / m or more and 80 mN / m or less. More preferably, it is 60 mN / m or more and 80 mN / m or less, More preferably, it is 65 mN / m or more and 80 mN / m or less. In addition, the surface free energy of a laminated film is the value measured in the state before apply | coating a coating liquid.

  When the surface free energy of the laminated film is 50 mN / m or more, it becomes possible to have hydrophilicity, and it becomes possible to uniformly apply the W / O type emulsion.

  In addition, as another method for setting the surface free energy of the laminated film in the range of 50 mN / m or more and 80 mN / m or less, there are known methods such as corona discharge treatment and plasma treatment on the substrate, but they are left for a long time. This is preferable because the effect is reduced, blocking occurs after the film roll is formed, and the electrode, metal, nitrogen and oxygen in the air react with each other during processing, and dust is generated.

  The method for applying the coating liquid 1 used for forming the laminated film is not particularly limited as long as the laminated film can be formed on the substrate. For example, wire bar coating, gravure coating method, comma coating method, die coating method, dipping method A known method such as an applicator method or a spray coating method can be used.

  In addition, after applying the coating liquid 1 for forming a laminated film, the drying is preferably performed at room temperature or more and 100 ° C. or less. If it is normal temperature or more and 100 degrees C or less, there will be no limitation in the drying method in particular, For example, a dryer, a hot air dryer, a floating oven etc. can be used. When the drying is less than room temperature, the solvent contained in the coating liquid 1 may not volatilize, and when the temperature is higher than 100 ° C., the structure of the surfactant contained in the coating liquid 1 is decomposed, The characteristics of the surfactant itself may not be obtained.

  The laminated film of the present invention is soluble in the organic solvent and / or water in the coating liquid 2 when making the conductive substrate, and when the laminated film is used as the conductive substrate, the laminated film becomes the organic solvent and / or in the coating liquid 2. Or it is preferable not to melt | dissolve in water. The laminated film may remain as one layer. However, since the laminated film is soluble in the coating liquid 2, it becomes easy to obtain a conductive substrate having the characteristics of the present invention. It is preferable that the laminated film is not dissolved in the coating liquid 2.

  In the present invention, when the coating liquid 2 is applied, the temperature of the laminated film is preferably 5 ° C. or higher and lower than 35 ° C. By setting the temperature of the laminated film within this range, it is possible to easily exhibit the characteristics of the surfactant contained in the coating liquid 1.

The method for measuring the temperature of the laminated film is not particularly limited as long as it is a measuring instrument that can measure the temperature of the laminated film surface, but for example, a non-contact type temperature such as a radiation temperature sensor or an infrared radiation thermometer. A measuring device can be used.

When the temperature of the laminated film is set to less than 5 ° C. and the coating liquid 2 is applied, the surface of the laminated film may be condensed, or the aqueous solvent in the emulsion of the coating liquid 2 may solidify and the structure may be broken. When the conductive substrate of the present invention is used, it is not preferable because transparency and conductivity cannot be obtained. Further, when the temperature of the laminated film is set to 35 ° C. or higher, it may be higher than the freezing point temperature of the surfactant contained in the coating liquid 1, and the surfactant itself may be melted. In this case, the surface of the laminated film becomes sticky, and in the production machine, when there is a step in which the laminated film side comes into contact with the roll while applying the coating liquid 1 after drying and applying the coating liquid 2, blocking with the roll occurs. The laminated film may be transferred to a roll, which may cause problems such as deterioration of productivity and coating quality such as line contamination and coating unevenness.

  The method for applying the coating liquid 2 used for forming a conductive substrate is not particularly limited as long as it can be a conductive substrate. For example, wire bar coating, gravure coating, comma coating, die coating, and dipping A known method such as an applicator method or a spray coating method can be used.

  Moreover, the method of drying after apply | coating the coating liquid 2 is not specifically limited, For example, a dryer, a hot air dryer, a floating oven etc. can be used.

  The conductivity of the conductive substrate of the present invention is preferably a surface specific resistance of 30Ω / □ or less. More preferably, it is 20 Ω / □ or less, and particularly preferably 15 Ω / □ or less. Moreover, although it is preferable that the conductivity of the conductive substrate is low, it is considered difficult to make it less than 1 Ω / □ in practice. Therefore, the lower limit of the surface specific resistance of the conductive substrate is considered to be 1Ω / □. When the surface specific resistance of the conductive substrate is 30 Ω / □ or less, when the conductive substrate is energized and used, the load caused by the resistance is reduced, so that heat generation can be suppressed and the conductive substrate can be used at a low voltage. It is preferable because it is possible. Moreover, when the surface specific resistance of the conductive substrate is 30 Ω / □ or less, it is preferable when used as a conductive substrate for various electromagnetic wave shielding applications, because the electromagnetic wave shielding property is improved.

  In order to impart conductivity to the conductive substrate of the present invention, it is preferable to use a step of heat-treating the substrate after drying or a step of treating with an organic solvent.

  The substrate used for the conductive substrate of the present invention is preferably a thermoplastic resin film from the viewpoint of excellent transparency, flexibility and processability. Thermoplastic resin film is a general term for films that are melted or softened by heat, and is not particularly limited, but representative examples include polyester films, polyolefin films such as polypropylene films and polyethylene films, and polylactic acid. A film, a polycarbonate film, an acrylic film such as a polymethyl methacrylate film or a polystyrene film, a polyamide film such as nylon, a polyvinyl chloride film, a polyurethane film, a fluorine film, or a polyphenylene sulfide film can be used.

  These thermoplastic resin films may be composed of homopolymers or copolymer polymers, but among these, in terms of mechanical properties, dimensional stability, transparency, polyester films, polypropylene films, Polyamide films are preferred, and polyester films are particularly preferred from the viewpoints of mechanical strength and versatility.

  In such a polyester film, polyester is a general term for polymers having an ester bond as a main bond chain, and includes ethylene terephthalate, propylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, propylene-2, It is preferable to use one having at least one component selected from 6-naphthalate, ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate as a main component. it can. These constituent components may be used alone or in combination of two or more. However, when quality, economy and the like are comprehensively judged, polyester having ethylene terephthalate as a main constituent, that is, polyethylene terephthalate is used. It is particularly preferable to use it. In addition, when heat or shrinkage stress acts on the substrate, polyethylene-2,6-naphthalate having excellent heat resistance and rigidity is more preferable. These polyesters may further be partially copolymerized with other dicarboxylic acid components and diol components, preferably 20 mol% or less.

  The intrinsic viscosity (measured in o-chlorophenol at 25 ° C.) of such polyester is preferably 0.4 to 1.2 dl / g, more preferably 0.5 to 0.8 dl / g. It is suitable for carrying out the invention.

  Further, in such a thermoplastic resin, for example, polyester, various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic lubricant, a pigment, a dye, organic or inorganic fine particles, Fillers, antistatic agents, nucleating agents and the like may be added to such an extent that the properties are not deteriorated.

  Such a thermoplastic resin film, such as a polyester film, is preferably biaxially oriented. Such a biaxially oriented polyester film is generally obtained by stretching an unstretched polyester sheet or film about 2.5 to 5 times in the longitudinal direction and in the width direction, and then performing heat treatment to complete the crystal orientation. Yes, it indicates a biaxially oriented pattern by wide-angle X-ray diffraction.

  The thickness of such a thermoplastic resin film, such as a polyester film, is not particularly limited and is appropriately selected depending on the application and type, but from the viewpoint of mechanical strength, handling properties, etc., preferably 10 to 500 μm, More preferably, it is 38-250 micrometers, Most preferably, it is 75-150 micrometers. For example, when a polyester film is used as the substrate, a composite film by coextrusion may be used. On the other hand, a film obtained by bonding the obtained film by various methods can also be used.

Hereinafter, although the manufacturing method of the electroconductive board | substrate of this invention is illustrated and demonstrated more concretely, this invention is not limited to this. That is, using a biaxially stretched polyester film as a substrate, a coating solution (coating solution 1) obtained by diluting a nonionic surfactant having a freezing point temperature of 48 ° C. to 2% by mass with acetone is applied to the substrate by a wire bar coating method. Then, the substrate is applied and dried to obtain a substrate on which a laminated film is formed. Next, a W / O type emulsion (coating liquid 2) containing fine metal particles is applied to the laminated film obtained above by a die coating method and dried in an oven at 150 ° C. for 2 minutes. An electrically conductive substrate can be obtained.
[Characteristic measurement method and effect evaluation method]
The method for measuring the characteristics of the conductive substrates prepared in each of the examples and comparative examples and the method for evaluating the effects are as follows.

(1) Freezing point temperature The freezing point temperature of the surfactant contained in the coating liquid 1 was measured according to JIS K0065 (1992). The measurement was performed three times, and the average value was defined as the freezing point temperature of the surfactant.

(2) Surface free energy Using four types of liquids, water, ethylene glycol, formamide, and methylene iodide as measurement liquids, each using a contact angle meter CA-D type manufactured by Kyowa Interface Chemical Co., Ltd. The static contact angle with respect to the liquid laminated film surface was determined. The components of the contact angle and the surface tension of the measurement liquid obtained for each liquid were substituted into the following equations, respectively, and simultaneous equations consisting of four equations were solved for γSd, γSp, and γSh.

(ΓSdγLd) 1/2 + (γSpγLp) 1/2 + (γShγLh)
1/2 = γL (1 + COS θ) / 2
However, γS = γSd + γSp + γSh
γL = γLd + γLp + γLh
γS, γSd, γSp, γSh are the surface free energy, dispersion force component, polar force component, hydrogen bond component of the laminated film surface, respectively, and γL, γLd, γLp, γLh are the surface free energy, dispersion of the measurement solution used, respectively. Represents force component, polar force component, hydrogen bond component. Here, the surface tension of each liquid used was Panzer (J. Panzer, J. Colloi).
d Interface Sci. , 44, 142 (1973). The unit of surface free energy is mN / m.

(3) HLB value The HLB value is calculated from the following formula from the cloudiness measured by the following method described on page 324 of the surfactant manual (edited by Nishiichiro et al., Published by Sangyo Tosho Co., Ltd., 1960). To do.
HLB value = 0.89 × clouding number + 1.11.
The cloudiness number is obtained by dissolving 0.5 g of an evaluation sample (surfactant) in 5 ml of 98% ethyl alcohol, titrating with a 2% phenol aqueous solution while stirring at 25 ° C., and ending the time when the liquid becomes turbid. And The number of ml of 2% phenol aqueous solution required for this titration is defined as the cloud number.

(4) Total light transmittance The total light transmittance was measured in the normal state (23 ° C., relative humidity 65%) after leaving the conductive substrate for 2 hours, and then fully automatic direct reading haze computer “HGM-” manufactured by Suga Test Instruments Co., Ltd. 2DP ". The average value measured at three locations at random was taken as the total light transmittance of the conductive substrate.

  If the total light transmittance of the conductive substrate is 70% or more, the transparency is good. In the case of a conductive substrate in which a conductive layer is laminated only on one side of the substrate, the substrate was placed so that light could enter from the side where the conductive layer was laminated.

(6) Conductivity Conductivity is determined in accordance with JIS-K-7194 (1994) under the atmosphere after leaving a conductive substrate in a normal state (23 ° C., relative humidity 65%) for 24 hours. It was carried out by measuring the surface specific resistance of the conductive layer using EP (Mitsubishi Chemical Corporation, model number: MCP-T360). The unit is Ω / □. In addition, this measuring device can measure below 1 × 10 ⁶ Ω / □. If the surface specific resistance is 30Ω / □ or less, the conductivity is good.

Next, the present invention will be described based on examples.
Example 1
(1) Preparation of coating liquid 1 0.3% by mass of surfactant (manufactured by Nippon Emulsifier Co., Ltd., New Coal 2360), 0.1% by mass of silicone (8029 ADDITIVE manufactured by Toray Dow Corning Co., Ltd.) with acetone (Sasaki) A coating solution dissolved in 99.6% by mass of Chemicals Co., Ltd. was used.
(2) Preparation of coating solution 2 Preliminarily stirred with a magnetic stirrer was 12.5 g of an aqueous solution in which 37.5 g of a silver fine particle solution (XA-9053 manufactured by Fujikura Kasei Co., Ltd.) and 0.5 g of a polyether-modified polydimethylsiloxane were dissolved. Thereafter, a coating solution stirred at 12000 rpm for 5 minutes with a homomixer (TK HOMO MIXER, manufactured by Tokushu Kika Kogyo Co., Ltd.) was used.
(3) Formation of conductive substrate On one side of a biaxially stretched polyethylene terephthalate film (Lumirror (registered trademark) U46 manufactured by Toray Industries, Inc.), the coating liquid 1 was applied with a wire bar so that the wet thickness was 6 μm. It dried and the laminated film which laminated | stacked the laminated film was obtained.

Subsequently, the laminated film obtained was placed under an air flow adjusted to an air temperature of 25 ° C. and a wind speed of 4 m / second, and the temperature of the laminated film surface of the laminated film was 25 ° C. on the laminated film. The coating liquid 2 was applied using a wire bar so as to have a wet thickness of 30 μm. After coating, a film in which a metal fine particle layer was laminated was obtained. The obtained film in which the metal fine particle layer was laminated was continuously heat-treated in an oven at 150 ° C. for 1 minute, then immersed in acetone (manufactured by Sasaki Chemical Co., Ltd.) for 30 seconds, and heat-treated at 170 ° C. for 2 minutes. A conductive substrate was obtained. The obtained conductive substrate was good in both transparency and conductivity.

(Example 2)
(1) Preparation of coating liquid 1 0.3% by mass of a surfactant (Aoki Yushi Kogyo Co., Ltd., Fine Surf 500), 0.1% by mass of silicone (8029 ADDITIVE manufactured by Toray Dow Corning Co., Ltd.) with acetone ( A coating solution added to 99.6% by mass of Sasaki Chemical Co., Ltd. and dissolved therein was used.
(2) Preparation of coating liquid 2 The same coating liquid 2 as in Example 1 was used.
(3) Formation of conductive substrate A conductive substrate was obtained in the same manner as in Example 1 except that the coating liquid 1 prepared in Example 2 was used. The obtained conductive substrate was good in both transparency and conductivity.

(Example 3)
(1) Preparation of coating solution 1 0.3% by mass of surfactant (Brownon BN-25 manufactured by Aoki Oil & Fat Co., Ltd.), 0.1% by mass of silicone (8029 ADDITIVE manufactured by Toray Dow Corning Co., Ltd.) in acetone A coating solution added to 99.6% by mass (manufactured by Sasaki Chemical Co., Ltd.) and dissolved therein was used.
(2) Preparation of coating liquid 2 The same coating liquid 2 as in Example 1 was used.
(3) Formation of Conductive Substrate A conductive substrate was obtained in the same manner as in Example 1 except that the coating liquid 1 prepared in Example 3 was used. The obtained conductive substrate was good in both transparency and conductivity.

Example 4
(1) Preparation of coating solution 1 0.3% by mass of a surfactant (Brownon BN-3 manufactured by Aoki Yushi Kogyo Co., Ltd.) and 0.1% by mass of silicone (8029 ADDITIVE manufactured by Toray Dow Corning Co., Ltd.) in acetone A coating solution added to 99.6% by mass (manufactured by Sasaki Chemical Co., Ltd.) and dissolved therein was used.
(2) Preparation of coating liquid 2 Silver fine particle aqueous dispersion (manufactured by Sigma-Aldrich Japan Co., Ltd.) was concentrated under reduced pressure using an evaporator, and then adjusted to 37.5 g of silver fine particle aqueous dispersion adjusted to a silver fine particle concentration of 10% by mass. 0.2 g of oxyethyl lauryl ether and 0.02 g of polyvinyl alcohol were added and pre-stirred with a magnetic stirrer to prepare a dispersion. Next, while stirring 12.5 g of toluene at 12000 rpm using a homomixer (TK HOMO MIXER, manufactured by Tokushu Kika Kogyo),
The dispersion liquid prepared as described above was gradually added. After all the dispersion liquid was added, stirring was further continued for 10 minutes to obtain an O / W type emulsion coating liquid.
(3) Formation of conductive substrate A conductive substrate was obtained in the same manner as in Example 1 except that the coating liquid 1 and the coating liquid 2 were changed to the coating liquid 1 and the coating liquid 2 prepared in Example 4, respectively. The obtained conductive substrate was good in both transparency and conductivity.

(Example 5)
The procedure was carried out except that the laminated film obtained was placed in an air flow adjusted to an air temperature of 5 ° C. and the wind speed adjusted to 4 m / sec, and the temperature of the laminated film surface of the laminated film was 5 ° C. and then the coating liquid 2 was applied. A conductive substrate was obtained in the same manner as in Example 1 and in the same coating solution. The obtained conductive substrate was good in both transparency and conductivity.

(Example 6)
The procedure was carried out except that the laminated film obtained was placed in an air stream adjusted to an air temperature of 35 ° C. and the wind speed adjusted to 4 m / second, and the temperature of the laminated film surface of the laminated film was 35 ° C. and then the coating liquid 2 was applied. A conductive substrate was obtained in the same manner as in Example 1 and in the same coating solution. The obtained conductive substrate was good in both transparency and conductivity.

(Comparative Example 1)
(1) Preparation of coating liquid 1 The same coating liquid 1 as in Example 4 was used.
(2) Preparation of coating liquid 2 The same coating liquid 2 as in Example 1 was used.
(3) Formation of conductive substrate A conductive substrate was obtained in the same manner as in Example 1, except that the coating liquid 1 prepared in Example 4 was used. The obtained conductive substrate was good in both transparency and conductivity.
(Comparative Example 2)
(1) Preparation of coating solution 1 The same coating solution 1 as in Example 1 was used.
(2) Preparation of coating solution 2 The same coating solution 2 as in Example 4 was used.
(3) Formation of conductive substrate A conductive substrate was obtained in the same manner as in Example 1 except that the coating liquid 2 was changed to the coating liquid 2 prepared in Example 4. The obtained conductive substrate was good in both transparency and conductivity.
Table 1 shows the characteristic evaluation results of Examples 1 to 6 and Comparative Examples 1 and 2.

  If the manufacturing method of the electroconductive board | substrate of this invention is used, the electroconductive board | substrate excellent in productivity, transparency, and electroconductivity can be obtained. Therefore, it can be suitably used for, for example, electromagnetic wave shielding applications and transparent sheet heating element applications.

Claims (6)

A method of manufacturing a conductive substrate having a substrate and a conductive layer,
A laminated film is formed on one side of the substrate by a step of applying a coating liquid containing a surfactant and a step of drying.
A conductive layer is formed by applying an emulsion coating liquid containing metal fine particles (hereinafter referred to as coating liquid 2) on the laminated film and a drying process.
The said surfactant and the coating liquid 2 satisfy | fill the following conditions 1 or 2, The manufacturing method of the electroconductive board | substrate characterized by the above-mentioned.
Condition 1: The surfactant has an HLB value of 10 or more and 20 or less, and the coating liquid 2 is a W / O emulsion coating liquid.
Condition 2: The surfactant has an HLB value of 3 or more and less than 10, and the coating solution 2 is an O / W emulsion coating solution.   The method for producing a conductive substrate according to claim 1, wherein a freezing point temperature of the surfactant is 35 ° C. or more and 100 ° C. or less.   The method for manufacturing a conductive substrate according to claim 1, wherein the surface free energy of the laminated film is 50 mN / m or more and 80 mN / m or less.   The method for producing a conductive substrate according to claim 1, wherein the surfactant is soluble in an organic solvent and / or water in the coating liquid 2.   The method for producing a conductive substrate according to claim 1, wherein the temperature of the laminated film when applying the coating liquid 2 is 5 ° C. or more and less than 35 ° C. 5.   The method for producing a conductive substrate according to claim 1, wherein the surface specific resistance of the conductive layer is 30 Ω / □ or less.