JP2008229950A - Conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive film excellent in heat resistance hard to hardly undergoing change in conductive characteristics or optical characteristics even if being processed through a process loaded with heat such as processes of manufacturing a display or touch panel or the like. <P>SOLUTION: The conductive film, of which the surface resistance change ratio is 30% or below and the haze value change ratio is 30% or below after three-hr heat treatment at 130°C, is obtained by laminating the layers (a)-(b) at least on one side of a base material film in this order. The layer (a) is an anchor layer with a thickness of 1.0-7.0 μm formed by curing a film containing a (meth)acrylate type electromagnetic curable component and the layer (b) is a conductive layer containing a conductive polymer, which is composed of polycationic polythiophene having a unit represented by the general formula (1) and a polyanion as a repeating unit as a main constituent component, wherein R<SP>1</SP>and R<SP>2</SP>independently represent hydrogen or a 1-4C alkyl group or a 1-12C alkylene group which may be arbitrarily replaced in combination. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive film. More specifically, it is excellent not only in transparency and conductivity but also in heat resistance, and is 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 that can be used.

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 film layer formed by applying a conductive polymer on a transparent substrate film (wet process) has flexibility in the film itself, and problems such as cracks hardly occur. 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 conductive films using these conductive polymers as transparent conductive coating layers are heated in the manufacturing process of devices, etc., oligomer components present in trace amounts in the base film are deposited, and the conductive layer There are problems such as adverse effects on the film, a decrease in conductivity and an increase in surface resistance, and an increase in the haze of the film. Conventionally, a method using an anchor coat has been proposed for the purpose of improving the adhesion of a conductive layer and improving the light transmittance using optical interference (Patent Document 4). A method for suppressing the decrease has not been proposed.

Japanese Patent Laid-Open No. 1-313521 JP 2002-193972 A JP 2003-286336 A JP 2006-294532 A

  The present invention has been made in view of the above-described background art, and its purpose is to make it difficult to change the conductive characteristics and optical characteristics even through a process in which heat is applied in a manufacturing process of a display or a touch panel. The object is to provide an excellent conductive film.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor derives from a base film if an anchor layer obtained by curing a film containing an electromagnetic wave curable component is provided between the conductive layer and the base film. The present inventors have found that it is possible to suppress deterioration of conductive properties and optical properties due to the influence of oligomers.

（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）
をこの順で有する導電性フィルムであって、１３０℃で３時間熱処理した後の表面抵抗変化率が３０％以下、かつヘイズ値の変化率が３０％以下であることを特徴とする導電性フィルム。」が提供される。 Thus, according to the present invention, "at least on one side of the base film,
(A) an anchor layer having a thickness of 1.0 to 7.0 μm formed by curing a film containing a (meth) acrylate-based electromagnetic wave curable component, and
(B) a conductive layer comprising, as a main constituent, a conductive polymer composed of a polycationic polythiophene and a polyanion having a unit represented by the following general formula as a main repeating unit;

(In the formula, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, or together, the alkylene group having 1 to 12 carbon atoms which may be optionally substituted together) Represents)
In this order, having a surface resistance change rate of 30% or less after heat treatment at 130 ° C. for 3 hours, and a haze value change rate of 30% or less. . Is provided.

Moreover, as a preferable aspect,
The total light transmittance is 60% or more and the surface resistance is 10 to 1 × 10 ⁴ Ω / □,
The base film is composed of polyethylene terephthalate or polyethylene naphthalate,
The conductive layer is coated on an anchor layer having a surface wetting index of 50 dynes / cm or more;
A conductive film comprising at least one of the above is provided.

  Since the conductive film of the present invention is provided with an anchor layer made of an electromagnetic wave curable component between a conductive layer mainly composed of a specific conductive polymer and a base film, when the film is heated, It is possible to prevent the conductive layer from being adversely affected by the generated oligomer component derived from the base film, and to suppress changes in conductive characteristics and optical characteristics. Therefore, the conductive film of the present invention can be particularly suitably used as a transparent electrode such as a transparent touch panel, a liquid crystal display (LCD), an organic electroluminescence element, an inorganic electroluminescence element, or an electromagnetic wave shielding material, taking advantage of the above-described characteristics. it can.

  First, the conductive film of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of the conductive film of the present invention, that is, an example of a layer structure. In FIG. 1, reference numeral 1 denotes a base film, reference numeral 2 denotes a conductive layer, and reference numeral 3 denotes an anchor layer. As can be seen from FIG. 1, the conductive film of the present invention is obtained by laminating an anchor layer on at least one surface of a base film, and further laminating a conductive layer thereon. As long as it has such a structure, other functional layers may be formed as long as the object of the present invention is not impaired. For example, an easy adhesion layer (reference numeral 4) between the anchor layer and the base film, An easy-adhesion layer, a hard coat layer (reference numeral 5), or the like may be provided on the side opposite to the surface on which the conductive layer is formed.

  As described above, the conductive film of the present invention needs to have an anchor layer formed by curing the components described later on at least one surface of the base film, and a conductive layer laminated on the anchor layer in this order. Furthermore, it is necessary that the rate of change in surface resistance after heat treatment at 130 ° C. for 3 hours is 30% or less and the rate of change in haze value is 30% or less. When the rate of change exceeds 30%, the durability is insufficient, and it becomes difficult to use it stably for a long time. Such a rate of change can be adjusted by selecting an electromagnetic wave curable component described later to increase the cross-linking ratio of the anchor layer and appropriately setting the usage ratio of the conductive polymer described later and the thickness of the conductive layer.

  The conductive film of the present invention further has a total light transmittance (measured in accordance with JIS K7150) of 60% or more, preferably 65% or more, and particularly preferably 70% or more. By doing so, it can be suitably used as a transparent electrode such as a liquid crystal display or a transparent touch panel or an electromagnetic shielding material. In addition, this total light transmittance can be adjusted by setting the film thickness of the base film mentioned later or a conductive layer suitably.

In addition, the surface resistance of the conductive layer of the conductive film of the present invention is in the range of 10 to ⁵ × 10 ⁵ Ω / □, when used as a transparent electrode such as a liquid crystal display or a transparent touch panel, or as an electromagnetic shielding material. From the viewpoints of the functions of the above, electromagnetic wave shielding characteristics, and the total light transmittance and cost. Further preferable surface resistance is in the range of 10 to 1 × 10 ⁴ Ω / □, particularly preferably in the range of 10 to 5 × 10 ³ Ω / □.

Hereinafter, each layer forming the conductive film of the present invention will be described in more detail.
<Anchor layer>
In this invention, in order to suppress the influence of the oligomer derived from a base film, the anchor layer formed by hardening | curing the film | membrane containing a (meth) acrylate type electromagnetic wave curable component is provided between a base film and a conductive layer. It is necessary to provide in. The (meth) acrylate-based electromagnetic-curing component used here is particularly suitable as long as it has a sufficient crosslinking density and can sufficiently seal an oligomer derived from a base film and can be cured by electromagnetic wave irradiation. Without limitation, a polyfunctional (meth) acrylate monomer having at least two (meth) acryloyl groups in the molecule, an oligomer obtained by partially polymerizing the monomer, and a (meth) acrylate group introduced into the side chain of the polymer Examples thereof include an electromagnetic wave curable polymer.

  Examples of polyfunctional (meth) acrylate compounds preferably used include neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolethane tri (meth) acrylate, and penta Erythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, alkyl-modified dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, alkyl-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol Hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane Tiger (meth) acrylate), melamine (meth) acrylate can be exemplified, and these may be used alone, may be used in combination of two or more.

  Commercial products of such polyfunctional (meth) acrylate compounds include Aronix M-400, M-450, M-305, M-309, M-310, M-315, M-320, TO-1200, TO -1231, TO-595, TO-756 (manufactured by Toagosei Co., Ltd.), KAYARD D-310, D-330, DPHA, DPHA-2C (manufactured by Nippon Kayaku Co., Ltd.), Nicalak MX-302 (manufactured by Sanwa Chemical Co., Ltd.) ) And the like.

  Such a polyfunctional (meth) acrylate compound may have a curable functional group other than the (meth) acryloyl group as necessary, or a compound having a curable functional group other than the (meth) acryloyl group. May be used in combination. Moreover, it is also possible to use the oligomer polymerized within the range in which the film | membrane can be formed, and the oligomer of about 2-20 mer of these compounds.

  The method for curing the anchor layer in the present invention is not particularly limited as long as it is irradiated with electromagnetic waves, but it is preferable to use a photopolymerization initiator in combination and irradiate ultraviolet rays or visible rays to cause photocuring (photocrosslinking). Examples of photopolymerization initiators preferably used include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, anthraquinone, benzaldehyde, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4 -Chlorobenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-methyl-1-1 [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenyl Examples thereof include phosphine oxide and bis- (2,6-dimethoxybenzoyl) 2,4,4-trimethylpentylphosphine oxide.

  The amount of the photopolymerization initiator added is preferably 10% by weight or less based on the weight of the anchor layer coating. When the addition amount exceeds 10% by weight, the photopolymerization initiator acts as a plasticizer, and the strength of the anchor layer may be reduced.

  In addition to the above-mentioned components, fine particles may be added to the anchor layer of the present invention for the purpose of improving the strength of the film. The fine particles used in such a case are preferably made of silicon oxide, aluminum oxide, or silicone resin from the viewpoint of film strength, slipperiness, optical properties, etc. of the cured film. Of these, silicon oxide is preferable from the viewpoint of high strength. These fine particles may be used alone or in combination of two or more.

  Such fine particles may be in the form of powder or solvent dispersion sol. However, in the case of solvent dispersion sol, the dispersion medium is an organic solvent from the viewpoint of compatibility with other components. It is preferable. Examples of such organic solvents include alcohols such as methanol, ethanol, isopropanol, and butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, propylene glycol mono Examples thereof include esters such as ethyl ether acetate; ethers such as propylene glycol monomethyl ether and propylene glycol monomethyl ether; aromatic hydrocarbons such as benzene, toluene and xylene. Of these, methanol, isopropanol, butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene and xylene are preferred.

  The average primary particle size of the fine particles is preferably 2 to 2000 nm, more preferably 3 to 200 nm, and most preferably 5 to 100 nm. When the average primary particle size exceeds 2000 nm, it becomes difficult to obtain a highly transparent film. On the other hand, when the average primary particle size is less than 2 nm, the strength of the particles themselves is low and the hardness is low. A high film cannot be obtained. In order to improve the dispersibility of such fine particles, various surfactants and amines may be used in combination.

Examples of the silicon oxide fine particles preferably used include the following fine particle-dispersed sols that are commercially available. IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40 (manufactured by Nissan Chemical Co., Ltd.).
Examples of the aluminum oxide fine particles that are preferably used include the following fine particle-dispersed sols. Alumina sol-100, alumina sol-200, alumina sol-500 (manufactured by Nissan Scientific Co., Ltd.), AS-150I, AS-150T (manufactured by Sumitomo Osaka Cement).
Examples of the silicone resin fine particles preferably used include N-31-4 (manufactured by Nippon Pure Chemical Co., Ltd.) which is commercially available.

  The fine particles described above have a surface having a polymerizable functional group from the viewpoint of improving the dispersibility and from the viewpoint of improving the film strength by forming a crosslink with the (meth) acrylate-based electromagnetic wave curable component (matrix resin). It is preferable that the surface treatment is performed in advance with a treatment agent. Examples of the surface treatment agent preferably used include a compound containing a silanol group or generating a silanol group by hydrolysis (hereinafter sometimes referred to as a silane coupling agent). Of these, a silane coupling agent having a polymerizable functional group other than a silanol group is preferable. The silanol group of the compound and the hydroxyl group on the surface of the fine particles can form a bond by heat or the like, and a silane coupling agent is bonded to the surface of the fine particle, so that the fine particles are easily dispersed in the organic component. be able to. Examples of polymerizable functional groups other than silanol groups include acryloyl group, methacryloyl group, vinyl group, propenyl group, butadienyl group, styryl group, ethynyl group, acrylamide group and hydroxyl group.

  Examples of the compound having a polymerizable functional group other than the silanol group include TSL-8350, TSL-8337, TSL-8370, TSL-8375 (manufactured by GE Toshiba Silicone), A-9530, (new Nakamura Chemical Co., Ltd.), A-187 (manufactured by Nippon Unica), and the like.

When surface treatment of fine particles is performed, first the silane coupling agent and the fine particles to be treated (dispersed sol) are mixed, and after adding ion-exchanged water, the mixture is allowed to stand at room temperature. Proceed with hydrolysis of ring agent. The time required for hydrolysis varies depending on the type of compound used, but is about 1 to 24 hours. After the hydrolysis of the silane coupling agent has proceeded sufficiently, the silanol groups of the silane coupling agent react with the hydroxyl groups on the particle surface by treating at a temperature of 20 ° C. to 150 ° C. Obtainable.
The addition amount of the fine particles described above is preferably 5 to 90% by weight, particularly preferably 10 to 85% by weight, based on the weight of the anchor layer to be formed.

  The anchor layer of the present invention is applied, for example, by dissolving and dispersing the above-mentioned polyfunctional (meth) acrylate-based electromagnetic wave curable compound, if necessary (surface-treated) fine particles and a photopolymerization initiator in a solvent, It is formed by drying and curing by light irradiation. The solvent used here is not particularly limited, but for example, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, alcohols such as methanol, ethanol, propanol, n-butanol, secondary butanol, t-butanol and isopropyl alcohol, acetic acid Examples thereof include esters such as butyl and ethyl acetate, toluene, xylene, and aromatic hydrocarbons. Of these, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and acetylacetone are preferred from the viewpoint of solubility. The organic solvent is preferably used in such a range that the total solid content of the solution for forming the anchor layer is 1 to 70% by weight.

  In the anchor layer of the present invention, a photosensitizer, a leveling agent, a plasticizer, an ultraviolet absorber, an antioxidant, an antistatic agent, a pigment, a dye and the like may be used in combination as long as the object of the present invention is not impaired. Absent.

If the thickness of the anchor layer of the present invention becomes too thin, the effect of sealing the oligomer from the base film becomes insufficient, and in the case of radical curing reaction, the influence of oxygen damage becomes large, resulting in poor curing. On the contrary, if the film is too thick, the flexibility of the film is reduced and the film is easily broken when it is bent. Therefore, a range of 1.0 to 7.0 μm is necessary, and particularly 2.0 to 6.0 μm. The range is preferable.
In order to cure such an anchor layer by irradiating it with electromagnetic waves, after application and drying, for example, in the case of ultraviolet irradiation, the irradiation amount is 10 to 2000 mJ / cm ² , preferably 50 to 1500 mJ / cm ² , particularly preferably 100. What is necessary is just to set it as the range used as -1000mJ / cm < ² >.

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なる導電性高分子を主たる構成成分として含む組成物から形成される。すなわち、この導電性高分子はポリ（３，４−ジ置換チオフェン）とポリアニオンとの複合化合物である。 <Conductive layer>
The conductive layer in the present invention has the following general formula that has a reduced surface resistance and also has transparency.

As a main component, a polycationic polythiophene composed of repeating units represented by the formula (hereinafter sometimes referred to as “poly (3,4-disubstituted thiophene)”) and a polyanion is included. Formed from the composition. That is, this conductive polymer is a composite compound of poly (3,4-disubstituted thiophene) and a polyanion.

R ¹ and R ² of the poly (3,4-disubstituted thiophene) constituting the conductive polymer each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, or together. And an optionally substituted alkylene group having 1 to 12 carbon atoms. 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. Specific examples include a methylene group which may be alkyl-substituted, a 1,2-ethylene group and a 1,3-propylene group which may be substituted with a C 1-12 alkyl group or a phenyl group.

  On the other hand, examples of the polyanion constituting the conductive polymer include polymeric carboxylic acids (for example, polyacrylic acid, polymethacrylic acid, and polymaleic acid), and polymeric sulfonic acids (for example, polystyrene sulfonic acid, polyvinyl sulfonic acid, and the like). ) Etc. These polymeric carboxylic acids or sulfonic acids may be copolymers of vinyl carboxylic acid or 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 a conductive layer in the present invention uses a dispersion in which the above-described conductive polymer is dispersed in water as a main component, and polyester, polyacryl, polyurethane, polyvinyl acetate as necessary. A suitable organic polymer material such as polyvinyl butyral can be added as a binder.

  Further, for the purpose of improving the coating strength of the conductive layer to be obtained, alkoxysilane or acyloxysilane may be further added. These silane compounds are present in the conductive layer in the form of a reaction product that is hydrolyzed and then subjected to a 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 amount of the silane compound added is suitably 50% by weight or less, particularly 10 to 40% by weight based on the weight of the conductive polymer.

  In order to efficiently proceed the hydrolysis / condensation of the alkoxysilane, 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.

  Further, if necessary, an appropriate solvent compatible with water can be added for the purpose of improving the solubility and wettability to the substrate film, adjusting the solid content concentration, and the like. 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.

  Moreover, you may add a small amount of surfactant for the purpose of improving the wettability with respect to the base film of said coating composition. Preferred surfactants include nonionic surfactants (eg, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, sorbitan fatty acid ester, etc.), and fluorosurfactants (eg, fluoroalkylcarboxylates, Fluoroalkylbenzene sulfonate, perfluoroalkyl quaternary ammonium salt, perfluoroalkyl polyoxyethylene ethanol, etc.).

  As a coating method for forming the conductive 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. When a thermosetting resin is used in combination as a binder, coating of the conductive layer is performed by applying a coating liquid containing components for forming the conductive layer to the base film and drying by heating to form a coating film. The heating condition is preferably 80 to 160 ° C. for 10 to 120 seconds, particularly preferably 100 to 150 ° C. for 20 to 60 seconds. When an ultraviolet curable resin or an electron beam curable resin is used in combination as a binder, generally, preliminary drying is performed, followed by ultraviolet irradiation or electron beam irradiation.

  Further, when applying a coating liquid for forming such a conductive layer on the above-mentioned anchor layer, the surface of the anchor layer may be used as a preliminary treatment for further improving the adhesion and coating properties as necessary. May be subjected to physical surface treatment such as corona discharge treatment or plasma discharge treatment. The surface wetting index (surface tension) on the anchor layer after the surface treatment is preferably 50 dynes / cm or more, particularly preferably 60 dynes / cm or more. If the surface tension is as low as less than 50 dynes / cm, the effect of improving the wettability is insufficient, and the effect of improving the adhesion and coating properties of the conductive layer is reduced.

  The thickness of the conductive layer of the present invention described above 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 conductive layer is too thin, sufficient conductivity may not be obtained. Conversely, if it is too thick, the total light transmittance may be insufficient or blocking may occur.

(Easily adhesive layer)
In this invention, you may provide an easily bonding layer between the said anchor layer and a base film as needed. The component for forming such an easy-adhesion layer is not particularly limited as long as it has transparency such as polyurethane, polyacrylate, polyester, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl alcohol / polyethylene copolymer, etc. In particular, those containing both polyester resins and acrylic resins having an oxazoline group and a polyalkylene oxide chain as constituent components are preferred.

  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 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. Of 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 an alkylene oxide to a carboxyl group of acrylic acid or methacrylic acid. Examples of the polyalkylene oxide chain include polyethylene oxide, polypropylene oxide, and polybutylene oxide. The repeating unit of the polyalkylene oxide chain is preferably 3 to 100. By using such an acrylic resin having a polyalkylene oxide chain, the compatibility of the polyester resin and the acrylic resin in the anchor coat layer is improved compared to an acrylic resin not containing a polyacrylene oxide chain, and the transparency of the anchor coat layer is improved. 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 lowered. Conversely, when the repeating unit is larger than 100, the moisture and heat resistance of the anchor coat layer is lowered. Decrease, adhesion with the transparent conductive coating layer at high humidity and high temperature deteriorates. 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 the range of 5 to 30 weight%.

  Examples of other copolymer 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 , Vinyl trialkoxysilane, alkyl maleic 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.

  It is preferable that the content rate in the easily bonding layer of the polyester resin which forms an easily bonding layer is 5-95 weight%, and it is preferable that it is especially 50-90 weight%. The content of the acrylic resin having an oxazoline group and a polyalkylene oxide chain forming the easy adhesion layer in the easy adhesion layer is preferably 5 to 90% by weight, and more 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 easy-adhesion layer decreases and the adhesion of the anchor layer becomes insufficient. There is.

  In order to form the easy-adhesion layer (hereinafter sometimes referred to as “coating film”) on the base film, the above components may be used in the form of an aqueous coating solution such as an aqueous solution, aqueous dispersion or emulsion. preferable. In order to form a coating film, in addition to the above components, other components such as an antistatic agent, a colorant, a surfactant, and an ultraviolet absorber 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 easy-adhesion 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 easy-adhesive layer may be deteriorated. .

  The thickness of the easy-adhesion layer is not particularly limited as long as it exhibits a sufficient adhesion improving effect and does not impair the transparency, but is usually 0.001 to 0.10 μm, preferably 0.005 to 0.090 μm. Particularly preferred is a range of 0.01 to 0.085 μm.

  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) (20 mol% or less based on the total acid component, preferably 10% by mole or less of the third component may be copolymerized), a resin partially modified with a functional group such as an amino group, an epoxy group, a hydroxyl group, or a carbonyl group, a film made of triacetyl cellulose (TAC), etc. Is preferred. Of these substrate films, polyester (PET, PEN and their copolyester) 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 a polyester film is used as the base film, the above-mentioned coating application for providing an easy-adhesion layer can be carried out at an arbitrary stage, but is preferably carried out during the production process of the polyester film. In particular, it is preferably applied to a polyester film before the 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 easy-adhesion layer to an unstretched film or a uniaxially stretched film oriented in one direction, and then perform longitudinal stretching and / or lateral stretching and heat setting as it is.

  When applying an aqueous coating liquid for forming an easy-adhesion layer to a substrate film, physical treatment such as corona treatment, flame treatment, plasma treatment, etc. is performed on the film surface as a preliminary treatment for improving adhesion and coatability. It is preferable to perform a treatment or to use a chemically inert surfactant together with the coating composition.

  Such a surfactant promotes the wetting of the aqueous coating liquid that forms the easy-adhesion layer to the base film, such as 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.

  As a coating method for forming the easy-adhesion 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. can be exemplified. These methods can be used alone or in combination. In addition, a coating film may be formed only in the single side | surface of a film as needed, and may be formed in both surfaces.

  The conductive film of the present invention requires the anchor layer and the conductive layer to be laminated in this order on at least one surface of the base film as described above, but the surface opposite to the side on which the conductive layer is formed. Can be provided with a coating such as an easy-adhesion layer and a hard coat layer, if necessary.

  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 thickness of the anchor layer and the conductive layer was measured using a reflection spectral film thickness meter (trade name “FE-3000”, manufactured by Otsuka Electronics Co., Ltd.) with a wavelength of 300 to 800 nm on the conductive layer side of the conductive film sample. The reflectance was measured.
The thickness of the anchor layer was calculated by fitting using the peak valley method from the interference waveform of the reflection spectrum described above. On the other hand, the film thickness of the conductive layer was obtained by quoting the nk Cauchy dispersion formula as an approximate expression of the chromatic dispersion of the refractive index of the above-mentioned reflectance measurement value and fitting it with the measured spectrum value. .

(2) Wetting index of anchor layer surface According to JIS K6768, the wettability standard reagent was applied to the anchor layer surface, and the minimum reagent number that wets without water repellency for 2 seconds or more was taken as the wetting index of the anchor coat layer surface.

(3) Total light transmittance According to JIS K7150, it measured with the haze meter HCM-2B by Suga Test Instruments Co., Ltd.

(4) Surface resistance It measured based on JISK7194 using Mitsubishi Chemical Corporation Lorester MCP-T600. The measurement was performed five times at an arbitrary location, and the average value thereof was taken.

(5) Surface resistance change rate After the sample whose surface resistance was measured was placed in an oven at 130 ° C. for 3 hours, the surface resistance was measured in the same manner as described above, and the surface resistance change rate was calculated according to the following formula. .
Surface resistance change rate = (surface resistance after treatment / surface resistance before treatment−1) × 100 (%)
The smaller the surface resistance change rate represented by this formula, the better the heat resistance.

(6) Rate of change in haze value After the sample whose haze value was measured in accordance with JIS K7150 was placed in an oven at 130 ° C for 3 hours, the haze value was measured in the same manner as above, and the following formula was used. The change rate of the haze value was calculated.
Haze change rate = (haze value after treatment / haze value before treatment−1) × 100 (%)

(7) Flexibility After the prepared film sample is wound around a metal rod having a diameter of 10 mm and returned 50 times, the surface on which the anchor layer and the conductive layer are formed is observed with an optical microscope, and the coating surface is cracked. Confirmed whether or not.
○: No cracks were observed on the coating surface ×: Cracks were observed on the coating surface

[Example 1]
<Coating liquid component for easy adhesion layer formation>
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).

  Such a 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.)

  The acrylic was produced as follows according to the method described in JP-A-63-37167. That is, in a four-necked flask, 3 parts of sodium lauryl sulfonate and 181 parts of ion-exchanged water as surfactants were charged and heated to 60 ° C. in a nitrogen stream, and then 0.5 parts of ammonium persulfate as a polymerization initiator, 0.2 part of sodium hydrogen nitrite was added, and further 23.3 parts of methyl methacrylate as monomers, 22.6 parts of 2-isopropenyl-2-oxazoline, 40.7 parts of polyethylene oxide (n = 10) methacrylate 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 (trade name NAROACTY N-70, manufactured by Sanyo Chemical Co., Ltd.)

<Formation of base film and easy adhesion layer>
Polyethylene terephthalate ([η] = 0.62 dl / g, Tg = 78 ° C.) was melt 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. A coating solution prepared by adjusting a coating solution composed of 60 parts of the above-described polyester, 30 parts of acrylic, 5 parts of additive, and 5 parts of a wetting agent to a concentration of 8% with ion-exchanged water was uniformly applied on both sides with a roll coater. 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., heat-fixed, and an easy-adhesion layer was formed. Got. The thickness of the easy-adhesion layer was 0.04 μm.

<Formation of anchor layer>
A coating agent (trade name: Z7501: manufactured by JSR Corporation) containing dipentaerythritol hexa (meth) acrylate and silica nanoparticles as main components was adjusted to a solid content concentration of 40% with MEK, and uniformly applied with a roll coater. Next, after the coating, a drying treatment was performed at 70 ° C. for 2 minutes, and then ultraviolet irradiation was performed with a high pressure mercury lamp. The ultraviolet irradiation amount was 300 mJ / cm ² . The dry thickness of the anchor layer was 6.0 μm. Subsequently, the surface of the obtained anchor layer was subjected to corona treatment at an output of 4 kW and a treatment speed of 10 m / min. The wetting index of the anchor layer surface was 65 dynes / cm.

<Formation of conductive layer>
Conductive polymer: aqueous dispersion of polymer (BaytronP: Bayer) comprising 0.5% by weight of poly (3,4-ethylenedioxythiophene) and 0.8% by weight of polystyrene sulfonic acid (molecular weight Mn = 150,000) AG) A solution prepared by adding 3 parts diethylene glycol and 0.5 parts γ-glycidoxytrimethoxysilane to 97 parts was prepared on a base film provided with the anchor layer using a Meyer bar. And dried at 140 ° C. for 1 minute to form a conductive layer. The conductive layer thickness was 0.08 μm. Table 1 shows the properties of the obtained conductive film.

[Example 2]
The same operation as in Example 1 was performed except that the thickness of the anchor layer was set to 3.0 μm. The results are shown in Table 1.

[Example 3]
On the surface opposite to the surface on which the anchor layer and conductive layer are formed, a commercially available hard coat coating solution (EXF-D202: manufactured by Dainichi Seika) is diluted with MEK to a solid content of 40% with a bar coater. Thereafter, drying at 70 ° C. for 1 minute and ultraviolet irradiation with a high-pressure mercury lamp were performed at an irradiation intensity of 300 mJ / cm ² . The film thickness of the obtained hard coat layer was 5.0 μm. The results are shown in Table 1.

[Comparative Example 1]
The same operation as in Example 1 was performed except that the thickness of the anchor layer was 0.8 μm. The results are shown in Table 1.

[Comparative Example 2]
The same operation as in Example 1 was performed except that the thickness of the anchor layer was 9.0 μm. The results are shown in Table 1.

[Comparative Example 3]
The same operation as in Example 1 was performed except that the anchor layer was not formed. The results are shown in Table 1.

[Comparative Example 4]
The anchor layer was formed in the same manner as in Example 1 except for the following changes. The results are shown in Table 1.
A coating liquid consisting of 52 parts of an acrylic polyol resin (Dainippon Ink Chemical Co., Ltd., A801P), 8 parts of an isocyanate curing agent (Dainippon Ink Chemical Co., Ltd., DN981), and 40 parts of MEK was applied by a bar coater. An anchor layer having a thickness of 5.0 μm was formed by drying / curing at 140 ° C. for 1 minute.

  As can be seen from Table 1, the conductive film of the present invention has excellent heat resistance while maintaining properties such as transparency and initial surface resistance.

  Since the conductive film of the present invention described above has high heat resistance while maintaining excellent conductivity, a touch panel, a liquid crystal display (LCD), an organic electroluminescence element (OLED), an inorganic electroluminescence. It is extremely useful as a transparent electrode for an element or an electromagnetic shielding material.

It is sectional drawing which shows an example of the electroconductive film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base film 2 Conductive layer 3 Anchor layer 4 Easy adhesion layer 5 Hard-coat layer

Claims (4)

On at least one side of the base film,
(A) an anchor layer having a thickness of 1.0 to 7.0 μm formed by curing a film containing a (meth) acrylate-based electromagnetic wave curable component, and
(B) a conductive layer comprising, as a main constituent, a conductive polymer composed of a polycationic polythiophene and a polyanion having a unit represented by the following general formula as a main repeating unit;

(In the formula, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, or together, the alkylene group having 1 to 12 carbon atoms which may be optionally substituted together) Represents)
In this order, having a surface resistance change rate of 30% or less after heat treatment at 130 ° C. for 3 hours, and a haze value change rate of 30% or less. . The conductive film according to claim 1, wherein the total light transmittance of the conductive film is 60% or more and the surface resistance is 10 to 1 × 10 ⁴ Ω / □.   The conductive film according to claim 1 or 2, wherein the base film is composed of polyethylene terephthalate or polyethylene naphthalate.   The conductive film according to claim 1, wherein the conductive layer is coated on an anchor layer having a surface wetness index of 50 dynes / cm or more.

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