JP2008066064A - Conductive film and its forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive film capable of being used suitably in a usage field such as a transparent electrode and an electromagnetic wave shield material for, for example, a liquid crystal display (LCD) transparent touch panel, an organic electroluminescent element, an inorganic electroluminescent lamp, of which the usage in a large area has been increased recently, and which is superior in the in-plane uniformity of conductive performance. <P>SOLUTION: A water-base paint which contains a conductive polymer composed of polythiophene of a poly-cation shape and poly-anion composed of a repeating unit as expressed by a general formula 0.5-1.5 wt.%, a fluorochemical surfactant 100-1,000 ppm, and a wetting agent composed of a solvent having solubility with water 1-10 wt.% is applied on at least one side of the base film, and a conductive film having an average surface resistance value of 1 to 1×10<SP>4</SP>Ω/sq. and a fluctuation error of 3% or lower is obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conductive film. More specifically, since it is excellent in the uniformity of the conductive performance, it can be suitably used as a transparent electrode such as a liquid crystal display (LCD), a transparent touch panel, an organic electroluminescence element, an inorganic electroluminescence lamp, or an electromagnetic shielding material. The present invention relates to a conductive film.

Conventionally, a transparent conductive film is suitably used as a transparent electrode such as a liquid crystal display or a transparent touch panel or an electromagnetic shielding material. Examples of such transparent conductive films include indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), In ₂ O _{3 on} at least one surface of a transparent film surface such as polyethylene terephthalate (PET) or triacetyl cellulose (TAC). It is well known that a mixed sintered body (ITO) of SnO ₂ and SnO ₂ is provided by a dry process such as vacuum deposition, sputtering, or ion plating.

  However, the transparent conductive film usually has continuous processing and punching processing in a web shape, and is used in a bent state during surface processing and is also stored. In the conductive film, cracks may occur during the processing step or storage, and the surface resistance may increase.

  On the other hand, the transparent conductive coating layer formed by applying a conductive polymer on a transparent substrate film (wet process) has flexibility in the film itself and does not cause problems such as cracks. In addition, the method of obtaining a transparent conductive film by applying a conductive polymer has the advantage that the manufacturing cost is relatively low unlike the dry process, and the coating speed is generally high, so that the productivity is excellent. . Transparent conductive films obtained by applying such conductive polymers are charged with polythiophene, polyaniline, polypyrrole, etc., which have been generally used so far, because high conductivity cannot be obtained at the initial stage of development. The use was limited to the prevention use etc., or the hue of the conductive coating layer itself was problematic. However, these problems have recently been improved by improving the production method. For example, a conductive polymer (Patent Document 1) comprising a poly (3,4-dialkoxythiophene) obtained by oxidative polymerization of 3,4-dialkoxythiophene in the presence of a polyanion and a polyanion is a recent production method. (Patent Document 2 and Patent Document 3) improve the surface resistance while maintaining a high light transmittance.

  However, when the conductive film using these conductive polymers as a transparent conductive coating layer is applied to various applications, for example, when used for an analog touch panel proposed in Patent Document 4, input to the touch panel There may be a problem of erroneously detecting the position, and further improvement is required.

Japanese Patent Laid-Open No. 1-313521 JP 2002-193972 A JP 2003-286336 A JP 2002-109998 A

  This invention is made | formed in view of the said background art, The objective is to provide the electroconductive film which is excellent in the in-plane uniformity of electroconductive performance, and can be widely used for various application fields.

  As a result of intensive studies to achieve the above-mentioned problems, the inventor, when forming a transparent conductive coating layer made of a conductive polymer, contains a specific amount of a specific surfactant and wetting agent as a coating liquid. When used, the film thickness uniformity of the coating film was improved, and it was found that a conductive film in which variation in surface resistance within the surface was suppressed to a practical level was obtained, and the present invention was achieved.

（式中、Ｒ^１およびＲ^２は相互に独立して水素または炭素数１〜４のアルキル基を表すか、あるいは一緒になって任意に置換されてもよい炭素数１〜１２のアルキレン基を表す）
で表される繰返し単位からなるポリカチオン状のポリチオフェンとポリアニオンとからなる導電性高分子を含有する透明導電塗膜層が積層された導電性フィルムであって、該導電性フィルムの表面抵抗値が１〜１×１０^４Ω／□で、その変動誤差が３％以下であることを特徴とする導電性フィルム。」、および、「基材フィルムの少なくとも片面に、上記一般式で表される繰返し単位からなるポリカチオン状のポリチオフェンとポリアニオンとからなる導電性高分子を０．５〜１．５重量％、フッ素系界面活性剤を１００〜１０００ｐｐｍおよび水と相溶性のある溶媒からなる濡れ剤を１〜１０重量％含有する水系塗料を塗布することを特徴とする導電性フィルムの製造方法。」が提供される。 Thus, according to the present invention, “at least one side of the base film has the following general formula:

(Wherein R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, or an alkylene group having 1 to 12 carbon atoms which may be optionally substituted together) To express)
A conductive film in which a transparent conductive coating layer containing a conductive polymer composed of a polycationic polythiophene composed of repeating units represented by formula (II) and a polyanion is laminated, and the surface resistance value of the conductive film is 1 to 1 × 10 ⁴ Ω / □, and its variation error is 3% or less. ”And“ on at least one surface of the base film, a conductive polymer composed of a polycationic polythiophene composed of a repeating unit represented by the above general formula and a polyanion is added in an amount of 0.5 to 1.5% by weight, fluorine A method for producing a conductive film comprising applying a water-based paint containing 100 to 1000 ppm of a surfactant and 1 to 10% by weight of a wetting agent composed of a solvent compatible with water is provided. .

  Since the conductive film of the present invention is excellent in the in-plane uniformity of the surface resistance value of the transparent conductive coating layer, it can maintain sufficient practicality as a transparent conductive film even when used in a large area. Therefore, it can be suitably used as a transparent electrode or a transparent electromagnetic wave shielding material such as a transparent touch panel, a liquid crystal display, an organic electroluminescence element, an inorganic electroluminescent element, etc., which have recently been used in a large area.

  First, the conductive film of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a layer structure which is a preferred embodiment of the conductive film of the present invention. That is, in FIG. 1, the code | symbol 1 shows a base film, the code | symbol 3 shows a transparent conductive coating layer, and the codes | symbols 2 and 4 show the anchor coat layer and hard coat layer which may be provided as needed respectively.

Thus, although the conductive film of this invention requires that the transparent conductive coating film layer is laminated | stacked on the at least single side | surface of a base film, the surface resistance value is 1-1x10 < ⁴ > ohm / Must be in the range of □. When the surface resistance value exceeds the upper limit, when used as a transparent electrode such as a liquid crystal display or a transparent touch panel, or as an electromagnetic shielding material, it does not function sufficiently as an electrode, or sufficient electromagnetic shielding characteristics cannot be obtained. On the other hand, making it less than the lower limit is not preferable because the manufacturing process tends to be unstable. A preferable surface resistance value is in the range of 10 to 1 × 10 ⁴ Ω / □, particularly in the range of 10 to 5 × 10 ³ Ω / □.

Further, the variation error needs to be 3% or less, particularly 2% or less. Here, when the fluctuation error exceeds 3%, input stability when used as a touch panel is insufficient, or electromagnetic wave cutting performance becomes unstable, which is not preferable. The fluctuation error referred to here is the difference between the average value of the surface resistance values obtained by sampling any 50 points on a rectangular (17.43 cm × 30.99 cm) with a diagonal of 35.56 cm (14 inches). It is a value obtained by dividing the maximum value by the average surface resistance value. That is, it is calculated by the following formula.
Fluctuation error (%) = difference from average surface resistance value (maximum value) / average surface resistance value × 100

で表される繰返し単位からなるポリカチオン状のポリチオフェン（以下、“ポリ（３，４−ジ置換チオフェン）”と称することがある）とポリアニオンとから構成される導電性高分子（ａ）、すなわち複合化合物を含有することが必要である。 Hereinafter, each layer forming the conductive film of the present invention will be described in more detail.
The transparent conductive coating layer in the present invention has the following general formula:

A conductive polymer (a) composed of a polycationic polythiophene (hereinafter sometimes referred to as “poly (3,4-disubstituted thiophene)”) comprising a repeating unit represented by the following formula: It is necessary to contain complex compounds.

R ¹ and R ² of the poly (3,4-disubstituted thiophene) constituting the conductive polymer (a) each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, or together Represents an alkylene group having 1 to 12 carbon atoms which may be optionally substituted. As a typical example of the alkylene group having 1 to 12 carbon atoms which may be substituted and formed by R ¹ and R ² together, a 1,2-alkylene group (for example, 1,2- Cyclohexylene and 2,3-butylene). Further, preferable examples of the alkylene group having 1 to 12 carbon atoms formed by R ¹ and R ² together include methylene, 1,2-ethylene and 1,3-propylene groups. The 2-ethylene group is particularly preferred.

  On the other hand, examples of the polyanion constituting the conductive polymer (a) include polymeric carboxylic acids (for example, polyacrylic acid, polymethacrylic acid, polymaleic acid, etc.), polymeric sulfonic acids (for example, polystyrene sulfonic acid, polyvinyl sulfonic acid, etc.). ) Etc. These polymeric carboxylic acids and sulfonic acids may be copolymers of vinyl carboxylic acids and vinyl sulfonic acids with other polymerizable low molecular compounds such as acrylates and styrene. Among these polyanions, those having polystyrene sulfonic acid and all or part of which are metal salts are preferably used.

  The coating composition for forming the transparent conductive coating layer in the present invention uses a dispersion in which the above-mentioned conductive polymer is dispersed in water as a main component, but if necessary, polyester, polyacryl, polyurethane, A suitable organic polymer material such as polyvinyl acetate or polyvinyl butyral can be added as a binder.

  In the present invention, for the purpose of improving the wettability of the coating liquid to the base film, it is necessary to add a specific amount of a solvent compatible with water as a wetting agent. For example, alcohols (methanol, ethanol, propanol, isopropanol, etc.), amides (formamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide) and the like are preferable. Used. Of these, isopropanol is preferable from the viewpoint of compatibility with water and boiling point.

  The content of the wetting agent in the coating solution should be in the range of 1 to 10% by weight, preferably 1.5 to 9.5% by weight, more preferably 2 to 8% by weight. When this content is less than 1% by weight, the effect of the wetting agent becomes insufficient, and the uniformity of the obtained conductive performance becomes insufficient, which is not preferable. On the other hand, if it exceeds 10% by weight, the boiling point of the coating liquid changes too much, which adversely affects the drying conditions and the like, making it difficult to obtain uniform conductive performance.

  In addition to the above requirements, the coating liquid used in the present invention should further contain 100 to 1000 ppm, preferably 150 to 950 ppm, more preferably 200 to 900 ppm of a fluorosurfactant. Here, when the content is less than 100 ppm, the effect of controlling the wetting and spreading after coating does not appear, and it becomes difficult to obtain uniform conductive performance. On the other hand, if it exceeds 1000 ppm, the wetting and spreading effect will not increase any more, and surfactants that cannot be completely dissolved in the coating solution will be unevenly distributed in the coated film, which may adversely affect the conductive performance. Therefore, it is not preferable.

  Examples of the fluorosurfactant preferably used include fluoroalkyl carboxylates, perfluoroalkylbenzene sulfonates, perfluoroalkyl quaternary ammoniums, perfluoroalkyl / ether / alcohol copolymers, and perfluoroalkyl polyoxyethylene ethanol. Etc.

  Further, for the purpose of improving the coating strength of the transparent conductive coating layer obtained, alkoxysilane or acyloxysilane may be further added. These silane compounds are present in the transparent conductive coating layer in the form of a reaction product obtained by hydrolysis and subsequent condensation reaction. Examples of these silane compounds include methyltriacetoxysilane, dimethyldiacetoxysilane, trimethylacetoxysilane, tetraacetoxysilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetraisobutoxysilane, methyltriethoxysilane, dimethyl Examples thereof include diethoxysilane, trimethylethoxysilane, and phenyltriethoxysilane. Among them, reactive functional groups other than tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and tetraisobutoxysilane, and alkoxy groups such as γ-glycidoxypropyltrimethoxysilane and vinyltriethoxysilane. A trialkoxysilane having a glycidoxy group is particularly preferable. The ratio of the silane compound to the conductive polymer is suitably in the range of 1 to 300% by weight based on the weight of the conductive polymer.

  In order to efficiently proceed such hydrolysis / condensation of the silane compound, it is preferable to use a catalyst in combination. As the catalyst, either an acidic catalyst or a basic catalyst can be used. As the acidic catalyst, inorganic acids such as acetic acid, hydrochloric acid and nitric acid, and organic acids such as acetic acid, citric acid, propionic acid, oxalic acid and p-toluenesulfonic acid are suitable. On the other hand, as the basic catalyst, organic amine compounds such as ammonia, triethylamine and tripropylamine, and alkali metal compounds such as sodium methoxide, potassium methoxide, potassium ethoxide, sodium hydroxide and potassium hydroxide are suitable.

  As a coating method for forming the transparent conductive coating layer, a method known per se can be adopted. For example, the lip direct method, the comma coater method, the slit reverse method, the die coater method, the gravure roll coater method, the blade coater method, the spray coater method, the air knife coat method, the dip coat method, the bar coater method and the like are preferable. The drying conditions are 80 to 160 ° C., particularly 100 to 150 ° C., the drying time is usually adjusted appropriately between 10 and 120 seconds depending on the drying temperature, and it is preferable to perform heat treatment as necessary. . When a thermosetting resin is used as a binder, the transparent conductive coating layer is coated by applying a coating solution containing each component to the base film, followed by heat-drying to form a coating film. Let When a UV curable resin or an EB curable resin is used in combination as a binder, generally, after preliminary drying, ultraviolet irradiation or electron beam irradiation is performed.

  In addition, when applying a coating liquid for forming such a transparent conductive coating layer on a base film, the film surface may be used as a pretreatment for further improving the adhesion and coating properties as necessary. Further, physical surface treatment such as corona discharge treatment or plasma discharge treatment can be performed. Further, as described later, an anchor coat layer can be provided on the base film.

  The thickness of the transparent conductive coating layer is preferably in the range of 0.01 to 0.30 μm, particularly preferably in the range of 0.02 to 0.25 μm. If the thickness of the coating film is too thin, sufficient conductivity may not be obtained. Conversely, if it is too thick, light transmittance may be insufficient or blocking may occur.

  In this invention, in order to improve the adhesiveness of the said transparent conductive coating film layer and a base film, you may provide an anchor coat layer among these. Such an anchor coat layer is not particularly limited as long as it has excellent adhesion to the transparent conductive coating film layer and the substrate film and has transparency, but particularly has a polyester resin and an oxazoline group and a polyalkylene oxide chain. It is preferable that both the acrylic resin which has are included.

  The polyester resin used here is not particularly limited, and examples thereof include polyesters composed of the following polybasic acids and polyols, but are particularly soluble in water (may contain some organic solvent) or Dispersible polyesters are preferred.

  Examples of the polybasic acid component of the polyester resin include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, Examples include pyromellitic acid, dimer acid, and 5-sodium sulfoisophthalic acid. Of these, a copolyester containing two or more of these acid components is preferred. If the amount is slight, an unsaturated polybasic acid component such as maleic acid or itaconic acid, or a hydroxycarboxylic acid component such as p-hydroxybenzoic acid may be contained.

  Examples of the polyol component include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, dimethylolpropane, and poly ( Examples thereof include, but are not limited to, ethylene oxide) glycol and poly (tetramethylene oxide) glycol.

  On the other hand, the acrylic resin having an oxazoline group and a polyalkylene oxide chain used for the anchor coat layer is also preferably an acrylic resin that is soluble or dispersible in water (may contain some organic solvent). Examples of the acrylic resin having an oxazoline group and a polyalkyleneoxy chain include those containing the following monomers as copolymerization components.

  First, examples of the monomer having an oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-4-methyl. -2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline and the like, and one or a mixture of two or more of these can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. By using an acrylic resin having such an oxazoline group, the cohesive force of the anchor coat layer is improved, and the adhesion with the transparent conductive coating layer is further strengthened. Furthermore, the abrasion resistance with respect to the metal roll in a film forming process or a transparent conductive coating-film layer processing process can be provided to the base film surface. In addition, content of the monomer containing an oxazoline group is 2 to 40 weight% as content in this acrylic resin, Preferably it is 3 to 35 weight%, More preferably, it is 5 to 30 weight%.

  Next, examples of the monomer having a polyalkylene oxide chain include those obtained by adding polyalkylene oxide to an ester part of acrylic acid or methacrylic acid. Examples of the polyalkylene oxide chain include polymethylene oxide, polyethylene oxide, polypropylene oxide, and polybutylene oxide. The number of repeating units of the polyalkylene oxide chain is preferably 3 to 100. By using an acrylic resin having such a polyalkylene oxide chain, the compatibility of the polyester resin and the acrylic resin in the anchor coat layer is better than that of an acrylic resin not containing a polyacrylene oxide chain, and the anchor coat layer is transparent. Can be improved. Here, when the repeating unit of the polyalkylene oxide chain is smaller than 3, the compatibility between the polyester resin and the acrylic resin is lowered, and the transparency of the anchor coat layer is liable to be deteriorated. , And the adhesiveness with the transparent conductive coating layer at high humidity and high temperature tends to deteriorate. In addition, content of the monomer which has a polyalkylene oxide chain is 3 to 40 weight% as content in this acrylic resin, Preferably it is 4 to 35 weight%, More preferably, it is 5 to 30 weight%.

  Examples of other copolymerization components of the acrylic resin include the following monomers. That is, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.); 2- Hydroxy group-containing monomers such as hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate; Epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether; acrylic acid, methacrylic acid, Carboxy groups such as itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.) Is a monomer having a salt thereof; acrylamide, methacrylamide, N-alkyl acrylamide, N-alkyl methacrylamide, N, N-dialkyl acrylamide, N, N-dialkyl methacrylamide (the alkyl group is methyl, ethyl, n- Propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), acryloylmorpholine, N-methylolacrylamide, N-methylolmethacrylamide, N-phenylacrylamide, N -Monomers having an amide group such as phenylmethacrylamide; monomers of acid anhydrides such as maleic anhydride and itaconic anhydride; vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether , Vinyltrialkoxysilane, alkylmaleic acid monoester, alkyl fumaric acid monoester, alkylitaconic acid monoester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate, butadiene, etc. It is not limited to these monomers.

  The content ratio of the polyester resin forming the anchor coat layer in the anchor coat layer is preferably 5 to 95% by weight, and particularly preferably 50 to 90% by weight. The content of the acrylic resin having an oxazoline group and a polyalkylene oxide chain forming the anchor coat layer in the anchor coat layer is preferably 5 to 90% by weight, and particularly preferably 10 to 50% by weight. When the polyester resin exceeds 95% by weight, or the acrylic resin having an oxazoline group and a polyalkylene oxide chain is less than 5% by weight, the cohesive force of the anchor coat layer is lowered and the adhesiveness of the transparent conductive coating layer is insufficient. There is a case. On the other hand, when the polyester resin is less than 5% by weight or the acrylic resin having an oxazoline group and a polyalkylene oxide chain exceeds 95% by weight, the adhesion between the base film and the anchor coat layer may be lowered.

  The anchor coat layer preferably contains an aliphatic wax in an amount of 0.5 to 30% by weight, and more preferably 1 to 10% by weight. When this ratio is less than 0.5% by weight, the effect of improving the smoothness of the film surface may not be recognized. On the other hand, when it exceeds 30% by weight, the adhesion to the base film and the anchor coat property to the transparent conductive coating layer may be insufficient.

  Specific examples of aliphatic waxes that can be preferably used include carnauba wax, candelilla wax, rice wax, wood wax, jojoba oil, palm wax, rosin modified wax, olicuric wax, sugar cane wax, esparto wax, bark wax, etc. Plant waxes, animal waxes such as beeswax, lanolin, whale wax, shellac wax, mineral waxes such as montan wax, ozokerite, ceresin wax, petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam, fishertro Examples thereof include synthetic hydrocarbon waxes such as push wax, polyethylene wax, and polypropylene wax. Of these, carnauba wax, paraffin wax, and polyethylene wax are preferred because of the good transparency and smoothness of the transparent conductive coating layer. These waxes are preferably water-dispersed from the viewpoints of environmental problems and ease of handling.

  Further, the anchor coat layer preferably contains 0.1 to 20% by weight of a filler having an average particle diameter in the range of 0.005 to 0.5 μm. When the content of the filler in the anchor coat layer is less than 0.1% by weight, the slipperiness of the film may be lowered and it may be difficult to wind it into a roll. On the other hand, if it exceeds 20% by weight, the transparency of the anchor coat layer is lowered, and it may be impossible to use depending on the application such as a display / touch panel. As fillers preferably used, for example, calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide, oxidation Examples include inorganic fine particles such as antimony, carbon black, molybdenum disulfide, and organic fine particles such as acrylic cross-linked polymers, styrenic cross-linked polymers, silicone resins, fluororesins, benzoguanamine resins, phenol resins, nylon resins, and polyethylene waxes. it can. Among these, it is preferable to use a water-insoluble solid substance whose specific gravity does not exceed 3 in order to prevent sedimentation in an aqueous dispersion.

  Next, in order to form the anchor coat layer (hereinafter sometimes referred to as “coating film”) on the base film, the above components are used in the form of an aqueous coating liquid such as an aqueous solution, aqueous dispersion or emulsion. It is preferable to do. In order to form a coating film, other components other than the above components, for example, an antistatic agent, a colorant, a surfactant, an ultraviolet absorber and the like can be added as necessary. In particular, the addition of a lubricant can further improve the blocking resistance.

  The solid content concentration of the aqueous coating liquid used for coating the anchor coat layer is usually 20% by weight or less, but preferably 1 to 10% by weight. If this ratio is less than 1% by weight, the wettability to the substrate film may be insufficient, while if it exceeds 20% by weight, the storage stability of the coating liquid and the appearance of the anchor coat layer may be deteriorated. .

  Next, the base film in the present invention is not particularly limited, but (meth) acrylic resin, polystyrene, polyvinyl acetate, polyolefin such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, polyimide, polyamide, Polysulfone, polycarbonate, polyethylene terephthalate (hereinafter sometimes referred to as PET), polyester such as polyethylene naphthalate (hereinafter sometimes referred to as PEN) (a small amount, for example, 20 mol% or less based on the total acid component, Preferably, it may be a polyester copolymerized with 10 mol% or less of the third component), a resin partially modified with a functional group such as amino group, epoxy group, hydroxyl group, carbonyl group, triacetyl cellulose (TAC) ) Etc. are suitable. That. Of these substrate films, polyester (PET, PEN and their copolymers) films are particularly preferred from the viewpoints of mechanical properties, transparency, and production costs. The thickness of the base film is not particularly limited, but is preferably 500 μm or less. When it is thicker than 500 μm, the rigidity is too strong, and the handleability when the obtained film is attached to a display or the like tends to be lowered.

  When using a polyester film as a base film, the application of the above-mentioned water-based paint for providing an anchor coat layer can be carried out at any stage, but is preferably carried out during the production process of the polyester film, Furthermore, it is preferable to apply to the polyester film before orientation crystallization is completed.

  Here, the polyester film before completion of oriented crystallization is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in two directions, the longitudinal direction and the transverse direction. And the like that have been stretched and oriented at a low magnification (biaxially stretched film before being finally re-stretched in the machine direction or transverse direction to complete orientation crystallization).

  In particular, it is preferable to apply an aqueous coating liquid for forming an anchor coat layer to an unstretched film or a uniaxially stretched film oriented in one direction, and to perform longitudinal stretching and / or lateral stretching and heat setting as it is.

  When applying the aqueous coating liquid for forming the anchor coat layer to the base film, physical treatment such as corona treatment, flame treatment, plasma treatment, etc. is applied to the film surface as a preliminary treatment for improving the coatability. Alternatively, it is preferable to use a chemically inert surfactant together with the composition.

  Such a surfactant promotes the wetting of the aqueous coating liquid forming the anchor coat layer to the base film, and includes, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene-fatty acid ester, sorbitan aliphatic ester. And anionic and nonionic surfactants such as glycerin fatty acid esters, fatty acid metal soaps, alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates. It is preferable that 0.1 to 10 weight% of surfactant is contained in the composition which forms a coating film.

  The coating amount of the aqueous coating liquid for forming the anchor coat layer is preferably such an amount that the thickness of the coating film is in the range of 0.01 to 0.30 μm, preferably 0.02 to 0.25 μm. . If the thickness of the coating film is too thin, the adhesive force is reduced, and conversely if it is too thick, blocking may occur or the haze value may increase.

  As a coating method for forming the anchor coat layer, a method known per se may be employed. For example, lip direct method, comma coater method, slit reverse method, die coater method, gravure roll coater method, blade coater method, spray coater method, air knife coat method, dip coat method, bar coater method, etc. These methods can be used alone or in combination. In addition, a coating film may be formed only on one side of a film as needed, and may be formed on both surfaces.

  The conductive film of the present invention needs to have a transparent conductive coating layer laminated on at least one side of the base film as described above, but on the surface opposite to the side on which the transparent conductive coating layer is formed. If necessary, a coating film such as an anchor coat layer or a hard coat layer can be provided.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, each evaluation in an Example followed the following method.

(1) Film thickness The thicknesses of the anchor coat layer and the transparent conductive coating film layer are measured with a reflectance of a wavelength of 300 to 800 nm using a reflection spectral film thickness meter (manufactured by Otsuka Electronics, trade name “FE-3000”). The nk Cauchy dispersion formula was cited as an approximate expression for wavelength dispersion of a typical refractive index, and the film thickness was determined by fitting with the measured value of the spectrum.

(2) Glass transition temperature Approximately 10 mg of sample is sealed in an aluminum pan for measurement and attached to a differential calorimeter (DuPont V4.OB2000 DSC), and the temperature is increased from 25 ° C. to 300 ° C. at a rate of 20 ° C./min. The temperature is raised, held at 300 ° C. for 5 minutes, then taken out, immediately transferred onto ice and rapidly cooled. The pan is again attached to the differential calorimeter, and the glass transition temperature (Tg: ° C.) is measured by increasing the temperature from 25 ° C. to 300 ° C. at a rate of 20 ° C./min.

(3) Intrinsic viscosity Intrinsic viscosity ([η] dl / g) is measured with an o-chlorophenol solution at 25 ° C.

(4) Total light transmittance Measured with a haze meter HCM-2B manufactured by Suga Test Instruments Co., Ltd. according to JIS K7150.

(5) Surface resistance value (average value) and in-plane uniformity of surface resistance value Measured according to JIS K7194 using Lorester MCP-T600 manufactured by Mitsubishi Chemical Corporation. The measurement was performed by sampling any 50 points in a rectangular (17.43 cm × 30.99 cm) size of diagonal 35.56 cm (14 inches), and the average value was defined as the surface resistance value. A value obtained by dividing the difference by the average surface resistance value was defined as a variation error.
Fluctuation error (%) = difference from average surface resistance value at each point / average surface resistance value × 100

(6) Pen input sliding durability As a standard of the degree of conductivity deterioration when an external force is applied to the conductive film, a model touch panel was prepared and a pen input sliding durability test was performed. In the pen input sliding endurance test, a conductive film of a sample was cut out to 100 mm × 100 mm, and an electrode having a width of 5 mm was applied to both ends of the transparent conductive coating layer forming surface by applying silver paste. A voltage of 5 V is applied between the electrodes by a constant voltage power source, and the voltage Vi, j (i, j == at 2500 points from (x1, y1) to (x50, y50) in the range of 50 mm × 50 mm in the center of the sample at 1 mm vertical and horizontal intervals. 1-50) was measured. The deviation from the theoretical voltage Ui, j = V1,1 + (V50,50−V1,1) / 50 × (j−1) at each voltage measurement point is Δi, j = (Vi, j−Ui, j) / Ui, j is defined, and the maximum absolute value of Δi, j is defined as linearity.

A touch panel was prepared using a film whose linearity was measured before the pen input test. From the side of the panel plate made of conductive film, using a touch pen with a pen tip radius of 0.8 mm made of polyacetal resin, a part with a linearity measurement was used to plot characters from 2 cm square to katakana Written and performed a pen input test. At this time, the pen load was 250 gf, and the character writing speed was 2000 characters / hour. The conductive film was removed from the touch panel where writing was completed, and the linearity of the conductive film after the pen input test was measured by the same method as described above. This evaluation was performed for various numbers of written characters, and the number of characters when the linearity exceeded 3% was defined as the number of pen input durable characters, and evaluated according to the following criteria.
◎: 100,000 characters <number of endurance characters for pen input ・ ・ ・ Excellent resistance to external force ○: 50,000 characters ≦ number of endurance characters for pen input ≦ 100,000 characters ・ ・ ・ Good endurance to external force ×: endurance characters for pen input <50,000 characters ・ ・ ・ against external force Poor tolerance

(7) Electromagnetic wave shielding properties The electric field shielding property was measured using an electromagnetic wave shielding effect measuring device developed by Kansai Electronics Industry Promotion Center (KEC).

[Example 1]
<Formation of base film and anchor coat layer>
Molten polyethylene terephthalate ([η] = 0.62 dl / g, Tg = 78 ° C.) was extruded from a die, cooled with a cooling drum by a conventional method to form an unstretched film, and then stretched 3.4 times in the longitudinal direction. The coating solution for forming an anchor coat layer in which a coating solution comprising 60 parts of polyester, 30 parts of acrylic, 5 parts of additive, and 5 parts of a wetting agent is adjusted to 8% with ion-exchanged water is uniformly applied on a roll coater. It was applied to. Next, after coating, the film was stretched 3.6 times in the transverse direction at 125 ° C., shrunk 3% in the width direction at 220 ° C. and heat-fixed, and a base film with a thickness of 188 μm was formed. Got. The thickness of the anchor coat layer was 0.10 μm.

<Adjustment of anchor coat layer forming coating solution>
Polyester: The acid component is composed of 65 mol% of 2,6-naphthalenedicarboxylic acid / 30 mol% of isophthalic acid / 5 mol% of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% of ethylene glycol / 10 mol% of diethylene glycol. (Tg = 80 ° C., average molecular weight 13000).

  This polyester was produced as follows according to the method described in Example 1 of JP-A-6-116487. That is, 44 parts of dimethyl 2,6-naphthalenedicarboxylate, 4 parts of dimethyl isophthalate, 34 parts of ethylene glycol, and 2 parts of diethylene glycol were charged into a reactor, and 0.05 parts of tetrabutoxytitanium was added thereto, and the temperature was increased in a nitrogen atmosphere. Was controlled at 230 ° C. and heated, and the produced methanol was distilled off to carry out a transesterification reaction. Next, the temperature of the reaction system was gradually raised to 255 ° C., and the pressure inside the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain a polyester.

  Acrylic: 30 mol% methyl methacrylate / 2 mol of 2-isopropenyl-2-oxazoline / polyethylene oxide (n = 10) 10 mol% methacrylate / 30 mol% acrylamide (Tg = 50 ° C.)

  This acrylic was produced as follows according to the method described in Production Examples 1 to 3 of JP-A-63-37167. That is, 3 parts of sodium lauryl sulfonate and 181 parts of ion-exchanged water were added as surfactants to a four-necked flask, the temperature was raised to 60 ° C. in a nitrogen stream, then 0.5 parts of ammonium persulfate as a polymerization initiator, 0.2 part of sodium hydrogen nitrate was added, and 23.3 parts of methyl methacrylate as monomers, 22.6 parts of 2-isopropenyl-2-oxazoline, 40.7 parts of polyethylene oxide (n = 10) methacrylic acid A mixture of 13.3 parts of acrylamide was added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. After completion of dropping, the reaction was continued under stirring while maintaining the same temperature range for 2 hours, and then cooled to obtain an acrylic aqueous dispersion having a solid content of 35%.

Additive: Silica filler (average particle size 100 nm) (manufactured by Nissan Chemical Co., Ltd .: trade name Snowtex ZL)
Wetting agent: polyoxyethylene (n = 7) lauryl ether (manufactured by Sanyo Chemical Co., Ltd .: trade name NAROACTY N-70)

<Formation of transparent conductive coating layer>
Conductive polymer aqueous dispersion (BaytronP: Bayer AG) comprising 0.5% by weight of poly (3,4-ethylenedioxythiophene) and 0.8% by weight of polystyrene sulfonic acid (molecular weight Mn = 150,000) 97 parts) 3 parts diethylene glycol, 0.5 parts γ-glycidoxytrimethoxysilane, 4 parts isopropanol as wetting agent, fluorinated alkyl / ether / alcohol copolymer surfactant as surfactant A coating solution to which 400 ppm of an agent (manufactured by Dainippon Ink Chemical Co., Ltd., trade name: F-445) was added was applied onto the base film provided with the anchor coat layer using a Mayer bar, and the mixture was applied at 140 ° C. for 1 minute. Was dried to obtain a conductive film. The evaluation results are shown in Table 1. Moreover, it shows in FIG. 2 about the obtained electromagnetic wave shielding characteristic.

[Example 2]
The same operation as in Example 1 was repeated except that the thickness of the transparent conductive coating layer was changed. The evaluation results of the obtained conductive film are shown in Table 1. The obtained electromagnetic wave shielding characteristics are shown in FIG.

[Comparative Example 1]
The same operation as in Example 1 was repeated except that the method for forming the transparent conductive coating layer was changed as follows.
Conductive polymer aqueous dispersion (BaytronP: Bayer AG) comprising 0.5% by weight of poly (3,4-ethylenedioxythiophene) and 0.8% by weight of polystyrene sulfonic acid (molecular weight Mn = 150,000) 94 parts, isopropanol 6 parts as a wetting agent, fluorinated alkyl / ether / alcohol copolymer surfactant (product name: F-445, manufactured by Dainippon Ink & Chemicals) as a surfactant The applied coating solution was applied onto a substrate film provided with the anchor coat layer using a Mayer bar, and dried at 140 ° C. for 1 minute to obtain a conductive film. The evaluation results are shown in Table 1.

[Comparative Example 2]
The same operation as in Example 1 was repeated except that the method for forming the transparent conductive coating layer was changed as follows.
Conductive polymer aqueous dispersion (BaytronP: Bayer AG) comprising 0.5% by weight of poly (3,4-ethylenedioxythiophene) and 0.8% by weight of polystyrene sulfonic acid (molecular weight Mn = 150,000) Manufactured) 99.5 parts of isopropanol as a wetting agent, fluorinated alkyl ether / alcohol copolymer surfactant as a surfactant (Dainippon Ink Chemical Co., Ltd., trade name: F-445) Was applied onto the substrate film provided with the anchor coat layer using a Meyer bar, and dried at 140 ° C. for 1 minute to obtain a conductive film. The evaluation results are shown in Table 1.

[Comparative Example 3]
The same operation as in Example 1 was repeated except that no wetting agent was added to the coating liquid for forming the transparent conductive coating layer. The evaluation results are shown in Table 1.

[Comparative Example 4]
The same operation as in Example 1 was repeated except that the surfactant was not added to the coating liquid for forming the transparent conductive coating layer. The evaluation results are shown in Table 1.

  As can be seen from the above table, the conductive film of the present invention is excellent in in-plane uniformity of the surface resistance value.

  According to the conductive film of the present invention described above, since the in-plane uniformity of the conductive performance is excellent, liquid crystal displays (LCD), transparent touch panels, organic electroluminescence, which have recently been used in large areas. It can be suitably used as a transparent electrode such as an element or an inorganic electroluminescence lamp or an electromagnetic wave shielding material.

It is sectional drawing which shows an example of the electroconductive film of this invention. 4 is a measurement diagram showing electromagnetic wave shielding characteristics of the conductive film obtained in Example 1. FIG. 6 is a measurement diagram showing electromagnetic wave shielding characteristics of the conductive film obtained in Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base film 2 Anchor coat layer 3 Transparent conductive coating layer 4 Hard coat layer

Claims (11)

On at least one side of the base film, the following general formula

(Wherein R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, or an alkylene group having 1 to 12 carbon atoms which may be optionally substituted together) To express)
A conductive film in which a transparent conductive coating layer containing a conductive polymer composed of a polycationic polythiophene composed of repeating units represented by formula (II) and a polyanion is laminated, and the surface resistance value of the conductive film is 1 to 1 × 10 ⁴ Ω / □, and its variation error is 3% or less.   The conductive film according to claim 1, wherein the total light transmittance of the conductive film is 70% or more.   The transparent conductive coating film layer contains a reaction product derived from at least one silane compound selected from the group consisting of a tetraalkoxysilane and a trialkoxysilane having a reactive functional group other than an alkoxy group. 2. The conductive film according to 2.   The conductive film according to claim 3, wherein the silane compound is trialkoxysilane having a glycidoxy group.   The anchor coat layer containing an acrylic resin having a polyester resin and an oxazoline group and a polyalkylene oxide chain as a constituent component is provided between the base film and the transparent conductive coating layer. The electroconductive film of description.   The conductive film according to claim 1, wherein the base film is made of polyethylene terephthalate or polyethylene naphthalate. On at least one side of the base film, the following general formula

(Wherein R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, or an alkylene group having 1 to 12 carbon atoms which may be optionally substituted together) To express)
0.5 to 1.5% by weight of a conductive polymer composed of a polycationic polythiophene comprising a repeating unit represented by formula (II) and a polyanion, 100 to 1000 ppm of a fluorosurfactant, and a solvent compatible with water A method for producing a conductive film, comprising applying a water-based paint containing 1 to 10% by weight of a wetting agent.   The method for producing a conductive film according to claim 7, wherein the water-based paint further contains at least one silane compound selected from the group consisting of a tetraalkoxysilane and a trialkoxysilane having a reactive functional group other than an alkoxy group.   The method for producing a conductive film according to claim 8, wherein the silane compound is trialkoxysilane having a glycidoxy group.   Prior to application of the water-based paint, an anchor coat layer containing a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain as a constituent component is provided on the coated surface. A method for producing a conductive film.   The manufacturing method of the electroconductive film in any one of Claims 7-10 in which a base film is comprised with a polyethylene terephthalate or a polyethylene naphthalate.

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