JP5632614B2 - Transparent conductive film, touch panel and electronic device - Google Patents

Description

  The present invention relates to a transparent conductive film, a touch panel using the same, and an electronic device.

  Transparent conductive members that are transparent in the visible light region and have electrical conductivity include new display methods such as liquid crystal displays and electroluminescence displays, transparent electrodes in electronic devices such as touch panels and electronic paper, and charging of articles. It is used for prevention and electromagnetic wave shielding.

  Conventionally, as a transparent conductive member, so-called conductive glass in which an indium oxide thin film is formed on glass is well known, but conductive glass is flexible and workable because the base material is glass. It is inferior and may not be used depending on the application. Therefore, in recent years, transparent conductive films based on various plastic films such as polyethylene terephthalate have been used due to the advantages of flexibility, workability, impact resistance and light weight. Has been. In the case of a transparent conductive film used for a touch panel, transparency and scratch resistance are required. Therefore, it has been proposed to dispose a transparent dielectric layer between the transparent substrate and the transparent conductive layer (see, for example, Patent Documents 1 to 3).

JP-A-6-222352 JP 2002-316378 A JP 2002-326301 A

  However, the properties required for transparent conductive films vary widely, and prevention of yellowing of the transparent conductive film due to a decrease in the optical film thickness of the transparent dielectric layer under high temperature and high humidity, and the transparent conductive film Is required for interlayer adhesion under alkaline conditions such as a washing process when incorporated into an electronic device, and a transparent conductive film satisfying these characteristics is required.

  Therefore, the present invention prevents the yellowing of the transparent conductive film due to the decrease in the optical film thickness of the transparent dielectric layer under high temperature and high humidity, and further has a transparent conductive property with high interlayer adhesion under alkaline conditions. An object is to provide a film, and a touch panel and an electronic device using the film.

In order to achieve the above object, the transparent conductive film of the present invention is a transparent conductive film in which a transparent conductive layer is formed on one or both sides of a transparent substrate via a first transparent dielectric layer,
The first transparent dielectric layer is a copolymer having a structural unit I represented by the following formula i and a structural unit II represented by the following formula ii, or the structural unit I and the structural unit II and the following formula a copolymer having a structural unit III represented by iii,
In the copolymer, when the total of the structural units I, II and III is 100 mol%, the structural units I, II and III are 5-30 mol%, 40-95 mol% and 0-45, respectively. It is a transparent conductive film containing mol%.

[In Formula i, R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a —Z—R ³ group, and Z is a single bond or an alkylene group having 1 to 5 carbon atoms. R ³ is a substituent represented by Formula A,
In the formula ii, R ⁴ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁵ is a hydrogen atom or a monovalent substituent having 1 to 4 carbon atoms, and m is an integer of 0 to 4. Yes,
In the formula iii, R ⁶ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁷ is a monovalent substituent having 1 to 8 carbon atoms,
In Formula A, L ¹ is a divalent linking group, three R ⁸ are each independently an alkyl group having 1 to 8 carbon atoms, and n is an integer of 1 to 20. ]

  The transparent conductive film of the present invention is obtained by using a copolymer containing a structural unit I having a partial condensate of alkoxysilane in a side chain and a structural unit II formed from a styrene monomer component in a specific ratio. It is presumed that the decomposition of the copolymer due to the breakage of the chemical bond under high temperature and high humidity is suppressed, and the reduction of the thickness of the first transparent dielectric layer can be prevented. As a result, it is considered that yellowing of the transparent conductive film due to a decrease in the optical thickness of the first transparent dielectric layer can be prevented. Furthermore, according to the configuration of the present invention, good interlayer adhesion can be realized even under alkaline conditions.

In Formula A, L ¹ is preferably a linking group represented by Formula B below. This is because the curing reaction of the alkoxysilane partial condensate due to steric hindrance does not occur, so that a dense higher-order network structure can be obtained.

［前記式Ｂにおいて、Ｌ^２は単結合又は炭素数１〜８のアルキレン基である。］

[In Formula B, L ² represents a single bond or an alkylene group having 1 to 8 carbon atoms. ]

  In the transparent conductive film of the present invention, the refractive index of the first transparent dielectric layer is preferably 1.50 to 1.65. This is because adjustment of the refractive index difference between the transparent substrate and the first transparent dielectric layer and the refractive index difference between the first transparent dielectric layer and the transparent conductive layer is facilitated.

  In the transparent conductive film of the present invention, when the refractive index of the transparent substrate is n1, the refractive index of the first transparent dielectric layer is n2, and the refractive index of the transparent conductive layer is n3, n2 ≦ n1 <n3. It is preferable to satisfy this relationship. This is because the transparency of the transparent conductive film can be improved.

  In the transparent conductive film of the present invention, the first transparent dielectric disposed between the transparent substrate and the first transparent dielectric layer or between the first transparent dielectric layer and the transparent conductive layer. It is preferable to further have a second transparent dielectric layer having a refractive index different from that of the layer. This is because the transparency of the transparent conductive film can be improved.

  In the transparent conductive film of the present invention, when the first transparent dielectric layer is provided on one surface of the transparent substrate, the other surface of the transparent substrate is interposed with the first transparent adhesive layer. It is preferable to further have one or more transparent substrates bonded together. This is because the cushioning property of the transparent conductive film is improved.

  In the transparent conductive film of the present invention, the transparent substrate is preferably a decorative film. This is because a transparent conductive film having high design can be provided.

  When the transparent conductive film of the present invention further has the transparent substrate, it is preferable that at least one layer of the transparent substrate is a decorative film. This is because a transparent conductive film having high design can be provided.

  In the transparent conductive film of the present invention, when the first transparent dielectric layer is provided on one surface of the transparent substrate, the second transparent adhesive layer is interposed on the side farthest from the transparent conductive layer. It is preferable to further have a bonded release film. After peeling off the release film from the transparent conductive film, the transparent conductive film can be bonded to an adherend such as a touch panel via the second transparent adhesive layer. This is because it is possible to provide a transparent conductive film excellent in processability in a heat treatment step and the like. Further, in the transparent conductive film of the present invention, even when the first transparent dielectric layer and the transparent conductive layer are formed on both surfaces of the transparent substrate, the first transparent in one of the transparent conductive layers. It is preferable to further have a release film bonded to the surface opposite to the dielectric layer via the second transparent adhesive layer. This is because the same effect as described above can be obtained.

  Both the touch panel and the electronic device of the present invention include the above-described transparent conductive film of the present invention. According to the touch panel and the electronic device of the present invention, the same effects as those of the transparent conductive film of the present invention described above can be obtained.

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

  Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component and the overlapping description is abbreviate | omitted.

  FIG. 1 shows an example of the transparent conductive film of the present invention. A first transparent dielectric layer 2 and a transparent conductive layer 3 are formed in this order on one surface of a transparent substrate 1. FIG. 2 shows an example in which the first transparent dielectric layer 2 and the transparent conductive layer 3 are formed in this order on both surfaces of the transparent substrate 1.

  The transparent substrate 1 used in the present invention is not particularly limited, but various plastic films having transparency are used. For example, the materials include polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, polyvinyl chloride resins, poly Examples thereof include vinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, polyphenylene sulfide resins, and cycloolefin resins. Among these, polyester resins are preferable from the viewpoint of cost.

  The thickness of the transparent substrate 1 is preferably in the range of 1 to 300 μm, more preferably in the range of 2 to 200 μm, and still more preferably in the range of 20 to 150 μm. This is because it is easy to reduce the thickness of the transparent conductive film while ensuring the mechanical strength.

  The transparent substrate 1 is subjected to etching treatment such as sputtering, corona discharge, flame, ultraviolet ray irradiation, electron beam irradiation, chemical conversion, oxidation, undercoating treatment, etc. on the surface, and a first transparent dielectric layer provided thereon 2 can be improved in adhesion to the transparent substrate 1. Further, before the first transparent dielectric layer 2 is provided, the surface of the transparent substrate 1 may be removed and cleaned by solvent cleaning, ultrasonic cleaning, or the like, if necessary.

  The first transparent dielectric layer 2 is a copolymer having the structural unit I represented by the above formula i and the structural unit II represented by the above formula ii, or the structural unit I and the structural unit II and the above formula iii. A copolymer having the structural unit III represented. The copolymer may be a random copolymer or a block copolymer, but is preferably a random copolymer in consideration of transparency.

  And the said copolymer is 5-30 mol%, 40-95 mol%, and 0-45, respectively, when the total of structural unit I, II, and III is 100 mol%. Contains mol%. With this configuration, it is possible to prevent yellowing of the transparent conductive film due to a decrease in the optical thickness of the first transparent dielectric layer 2, and it is possible to realize good interlayer adhesion even under alkaline conditions. . In order to exhibit the effect of the present invention more effectively, the copolymer preferably contains 5 to 20 mol%, 45 to 95 mol% and 0 to 45 mol% of the structural units I, II and III, respectively. In addition, in the 1st transparent dielectric material layer 2, other components, such as a filler, can be added as needed for adjustment of a refractive index and an internal haze.

In the above formula i, R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a —Z—R ³ group, and Z is a single bond or an alkylene group having 1 to 5 carbon atoms. , R ³ is a substituent represented by the above formula A. Here, R ¹ and R ² may have any structure such as linear, branched or cyclic, and may contain a functional group such as a hydroxyl group or a carboxyl group. The same applies to the following R ^{4 to} R ⁸ . R ¹ and R ² are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, from the viewpoint that the polymerization reaction can proceed favorably without inhibiting the polymerization reaction due to steric hindrance, More preferably, they are a hydrogen atom or a methyl group.

In the above formula ii, R ⁴ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ⁴ is preferably a hydrogen atom or a methyl group from the viewpoint that the polymerization reaction can be favorably proceeded without inhibiting the polymerization reaction due to steric hindrance. In the above formulas ii, R ⁵ is a monovalent substituent having 1 to 4 carbon hydrogen atom or a carbon, m is an integer of 0-4. R ⁵ is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, or a methoxy group from the viewpoint that the polymerization reaction can be favorably proceeded without inhibiting the polymerization reaction due to steric hindrance. , An ethoxy group, an n-propoxy group, an n-butoxy group and the like are preferable. From the same viewpoint, m is preferably an integer of 0 to 1.

In the above formula iii, R ⁶ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, without causing inhibition of the polymerization reaction by steric hindrance, from the viewpoint that it is possible to proceed satisfactorily polymerization reaction, R ⁶ Is preferably a hydrogen atom or a methyl group. Further, in the above formula iii, R ⁷ is a monovalent substituent having 1 to 8 carbon atoms, and from the viewpoint that the polymerization reaction can proceed favorably without inhibiting the polymerization reaction due to steric hindrance. An alkyl group having 1 or 2 carbon atoms is preferable, and a methyl group is more preferable.

In the above formula A, L ¹ is a divalent linking group, preferably a linking group having 1 to 25 carbon atoms, and may be a linear or branched alkylene group or an arylene group. Since inhibition of the curing reaction of the alkoxysilane partial condensate due to steric hindrance does not occur, L ¹ is a linking group represented by the above formula B from the viewpoint that a dense higher-order network structure can be obtained. preferable. In the above formula B, L ² is a single bond or an alkylene group having 1 to 8 carbon atoms, and does not inhibit the curing reaction of the alkoxysilane partial condensate due to steric hindrance, so that a dense higher-order network structure is obtained. From the viewpoint of being capable of being formed, it is preferably a single bond or an alkylene group having 1 to 2 carbon atoms.

In the above formulas A, 3 one R ⁸ are each independently an alkyl group having 1 to 8 carbon atoms, from the viewpoint of high reactivity at the time of dealcoholization reaction, is an alkyl group having 1 or 2 carbon atoms It is preferable. Further, in the above formula A, n is an integer of 1 to 20, and in the dealcoholization reaction described later, n is used to reduce the amount of alkoxysilane that flows out of the system together with alcohol without reacting. It is preferably 2 or more, and n is preferably 11 or less in order to improve the reactivity during grafting described later.

  The method for obtaining the copolymer is not particularly limited, and an acrylic ester-based grafted monomer component in which a partial condensate of alkoxysilane is previously grafted as a monomer for forming the structural unit I is prepared, and the graft Or a method of obtaining a copolymer by polymerizing a monomer component, a styrene monomer component for forming the structural unit II, and an acrylate monomer component for forming the structural unit III as necessary. Alternatively, a method obtained by polymerizing a styrene monomer component and an acrylic acid monomer component and then grafting a partial condensate of alkoxysilane to the acrylic acid monomer component may be used. Alternatively, a method obtained by polymerizing a styrene-based monomer component, an acrylic acid-based monomer component, and an acrylate-based monomer component and then grafting a partial condensate of alkoxysilane to the acrylic acid-based monomer component may be used. The copolymer may be a random copolymer or a block copolymer, but is preferably a random copolymer in consideration of transparency. Examples of the random copolymerization initiator include peroxides such as benzoyl peroxide and radical polymerization initiators such as azobis compounds such as 2,2′-azobisisobutyronitrile.

  The solvent for producing the copolymer is not particularly limited as long as it does not react with the monomer component to be polymerized, dissolves the obtained copolymer well, and has a boiling point higher than the polymerization temperature. Can be used without restriction. Examples of the solvent include ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ester solvents such as ethyl acetate and butyl acetate, aromatic solvents such as toluene and xylene, and cellosolv solvents such as cellosolve acetate and methylcellosolve acetate. , Alcohol solvents such as methanol, ethanol, isopropyl alcohol, n-butyl alcohol and the like, and one kind or a mixture of two or more kinds can be used.

  As the styrene monomer component, one selected from styrene, α-methylstyrene, p-hydroxystyrene, etc., or a combination of two or more thereof can be used. Examples of acrylic ester monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t -Butyl (meth) acrylate, 2-ethylhexyl acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy One type selected from -3-phenoxypropyl (meth) acrylate, lactone-modified hydroxyl (meth) acrylate, or the like, or a combination of two or more types thereof can be used. As the acrylic acid monomer component, one kind selected from acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, etc., or a combination of two or more thereof can be used.

  As the grafting method, for example, after obtaining a partial condensate of epoxy-modified alkoxysilane by dealcoholizing a partial condensate of alkoxysilane and an epoxy compound having one hydroxyl group in one molecule, Examples thereof include a method obtained by carrying out a ring-opening ester reaction between this and a copolymer of a styrene monomer component and an acrylic acid monomer component. Alternatively, it may be obtained by a ring-opening ester reaction of a copolymer of a styrene monomer component, an acrylic acid monomer component, and an acrylate monomer component and a partial condensate of the epoxy-modified alkoxysilane.

  Examples of the epoxy compound having one hydroxyl group in one molecule include compounds represented by the following formula C, and specific examples include glycidol, 3,4-epoxy-1-butanol, 4,5-epoxy- Examples include 1-propanol, 5,6-epoxy-1-hexanol, and 7,8-epoxy-1-octanol.

［前記式Ｃにおいて、Ｌ^３は、炭素数１〜９のアルキレン基である。］

[In the formula C, ^{L 3} is an alkylene group having 1 to 9 carbon atoms. ]

  As the molecular weight of the copolymer in the previous stage to be reacted with the alkoxysilane partial condensate, the number average molecular weight is preferably about 5000 to 200000. When the number average molecular weight is 5000 or more, cracking of the first transparent dielectric layer 2 after curing can be prevented. On the other hand, when the number average molecular weight is 200,000 or less, since the increase in the solution viscosity of the copolymer in the previous stage to be reacted with the alkoxysilane partial condensate can be suppressed, handling becomes easy.

  The partial condensate of alkoxysilane is obtained by hydrolyzing and condensing hydrolyzable alkoxysilane in the presence of an acid or base catalyst and water. Examples of hydrolyzable alkoxysilanes include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, and tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, Such as methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane Trialkoxysilanes. Preferred hydrolyzable alkoxysilanes are tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetraisopropoxysilane, and more preferably tetraethoxysilane, tetrapropoxysilane, and tetraisopropoxysilane.

  The number average molecular weight of the alkoxysilane partial condensate is preferably about 230 to 2,000, that is, the average number of Si in one molecule is preferably 2 to 11. When the average number of Si is 2 or more, it is possible to reduce the amount of alkoxysilane that flows out of the system together with alcohol without reacting during the dealcoholization reaction. On the other hand, if the average number of Si is 11 or less, the reactivity at the time of grafting can be improved.

  The above dealcoholization reaction may be carried out while distilling off the alcohol produced by charging and heating each of the above components. The reaction temperature is about 50 to 150 ° C., and 110 ° C. or lower is preferable for suppressing excessive condensation. Moreover, 70 degreeC or more is preferable from a viewpoint of improving the reactivity. The total reaction time is about 1 to 15 hours.

  In the dealcoholization reaction, a known transesterification catalyst can be used to promote the reaction. Examples of the catalyst include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, strontium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium, boron, cadmium, and manganese. And such oxides, oxides thereof, organic metals, organic acid salts, halides, and alkoxy compounds. Among these, organic tin and organic acid tin are particularly preferable, and specifically, dibutyltin dilaurate is effective.

  The ring-opening ester reaction is preferably carried out by charging a copolymer and a partial condensate of an epoxy-modified alkoxysilane and heating it in a substantially anhydrous state. The main purpose of this reaction is to react the carboxyl group in the copolymer with the epoxy group in the partial condensate. At this stage, it is necessary to suppress the formation of silica due to the sol-gel reaction of the alkoxysilyl group part of the partial condensate. is there. For this purpose, the reaction temperature is about 50 to 120 ° C., preferably 60 to 100 ° C., and the total reaction time is preferably 1 to 30 hours.

  In the above ring-opening ester reaction, a conventionally known ring-opening esterification catalyst can be used for promoting the reaction. For example, tertiary amines such as 1,8-diaza-bicyclo [5.4.0] -7-undecene, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, Imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, benzimidazole, tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, etc. Organic phosphines, tetraphenylphosphonium / tetraphenylborate, 2-ethyl-4-methylimidazole / tetraphenylborate, N-methylmorpholine / tetraphenylborate, etc. Examples thereof include tetraphenyl boron salts. The catalyst can be used at a ratio of 0.01 to 5 parts by weight with respect to 100 parts by weight of the converted solid residue of the copolymer.

  The copolymer thus obtained has an alkoxy group derived from a partial condensate of alkoxysilane in the molecule. For the sol-gel reaction or dealcoholization condensation reaction when forming a cured product, it is preferable to keep about 50 to 95 mol% of the alkoxy groups in the partial condensation product of alkoxysilane unreacted. More preferably, ˜90 mol% is kept unreacted. The cured product formed by the sol-gel method or dealcoholization condensation has fine silica sites (higher network structure of siloxane bonds) generated by gelation of the portion derived from the alkoxysilane partial condensate.

  The first transparent dielectric layer 2 is prepared by, for example, diluting the copolymer obtained as described above with a solvent such as methyl ethyl ketone to prepare a coating solution, which is then coated on the transparent substrate 1, It is obtained by curing by heating.

  The refractive index of the first transparent dielectric layer 2 is preferably 1.50 to 1.65. This is because it is easy to adjust the refractive index difference between the transparent substrate 1 and the first transparent dielectric layer 2 and the refractive index difference between the first transparent dielectric layer 2 and the transparent conductive layer 3. In order to adjust the refractive index of the first transparent dielectric layer 2 within the above range, the ratio of the structural unit II and the structural unit III may be adjusted. Increasing the ratio of the structural unit II can increase the refractive index, and increasing the ratio of the structural unit III can decrease the refractive index.

  The thickness of the first transparent dielectric layer 2 is not particularly limited, but is preferably 5 nm or more in order to obtain a continuous film. In consideration of flexibility, the thickness is more preferably 5 nm to 10 μm, and further preferably 5 nm to 5 μm. Moreover, from a viewpoint of transparency, More preferably, it is 5 nm-1 micrometer.

  The transparent conductive layer 3 shown in FIG. 1 is formed on the first transparent dielectric layer 2. Examples of the forming method include a coating method, a sputtering method, a vacuum deposition method, an ion plating method, and the like, and an appropriate method can be employed depending on the type of material and the required film thickness.

  The material of the transparent conductive layer 3 is not particularly limited, and includes, for example, indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten. An oxide of at least one metal (or metalloid) selected from the group is used. If necessary, the oxide may further contain a metal element shown in the above group or an oxide thereof. For example, indium oxide containing tin oxide or tin oxide containing antimony is preferably used.

  The thickness of the transparent conductive layer 3 is preferably 5 to 100 nm and more preferably 5 to 50 nm from the viewpoint of transparency.

  Regarding the relationship of the refractive index of each layer, when the refractive index of the transparent substrate 1 is n1, the refractive index of the first transparent dielectric layer 2 is n2, and the refractive index of the transparent conductive layer 3 is n3, n2 ≦ n1 <n3 It is preferable to satisfy this relationship. This is because the transparency of the transparent conductive film can be improved. From the same viewpoint, the refractive index n1 of the transparent substrate 1 is preferably in the range of 1.35 to 1.70, and the refractive index n3 of the transparent conductive layer 3 is preferably in the range of 1.80 to 2.30. .

  Next, an embodiment of the present invention shown in FIG. 3 will be described. FIG. 3 shows an example of the transparent conductive film of the present invention, in which a second transparent dielectric layer 4 is disposed between the first transparent dielectric layer 2 and the transparent conductive layer 3. 1 differs from FIG. 1 only in that the hard coat layer 5 is disposed on the surface of the transparent substrate 1 opposite to the first transparent dielectric layer 2.

  By providing the second transparent dielectric layer 4, the transparency of the transparent conductive film can be improved.

As a forming material of the second transparent dielectric layer 4, NaF (1.3), Na ₃ AlF ₆ (1.35), LiF (1.36), MgF ₂ (1.38), CaF ₂ (1. 4), inorganic substances such as BaF ₂ (1.3) and SiO ₂ (1.46), acrylic resins having a refractive index of about 1.4 to 1.6, urethane resins, siloxane polymers, alkyd resins, etc. Of organic matter.

  The refractive index of each layer is such that the refractive index of the transparent substrate 1 is n1, the refractive index of the first transparent dielectric layer 2 is n2, the refractive index of the transparent conductive layer 3 is n3, and the refractive index of the second transparent dielectric layer 4 is. When the rate is n4, it is preferable to satisfy the relationship of n4 <n2 ≦ n1 <n3. This is because the transparency of the transparent conductive film can be further improved. In order to satisfy the above relationship, the refractive index of the second transparent dielectric layer 4 is preferably in the range of 1.35 to 1.50. Although not shown, when the second transparent dielectric layer 4, the first transparent dielectric layer 2 and the transparent conductive layer 3 are formed in this order on the transparent substrate 1, the transparency of the transparent conductive film In order to further improve the refractive index, it is preferable that the refractive index of each layer satisfies the relationship of n2 <n4 ≦ n1 <n3.

  The thickness of the second transparent dielectric layer 4 is not particularly limited, but is preferably 5 nm or more in order to obtain a continuous film. In consideration of flexibility, the thickness is more preferably 10 to 100 nm. Examples of the method for forming the second transparent dielectric layer 4 include a coating method, a sputtering method, a vacuum deposition method, an ion plating method, and the like, and an appropriate method is used depending on the type of material and the required film thickness. Can be adopted.

  The hard coat layer 5 has a function of preventing the occurrence of scratches that may enter when the transparent conductive film is used by being incorporated in an electronic device or when the transparent conductive film is produced. The material is not particularly limited as long as it is transparent and can improve the scratch resistance of the transparent conductive layer 3. For example, an acrylic resin, a urethane resin, an organosilane condensate, an alkyd resin, Organic substances such as melamine resins, silicone resins and epoxy resins can be used. Among these, it is preferable to use a resin material mainly composed of an acrylic resin because the scratch resistance of the transparent conductive layer 3 can be further improved.

  As a method for forming the hard coat layer 5, an appropriate method can be adopted depending on the type of material and the required film thickness. The thickness of the hard coat layer 5 is preferably 1 to 25 μm from the viewpoint of realizing good pencil hardness and curling reduction of the transparent conductive film.

  Next, an embodiment of the present invention shown in FIG. 4 will be described. FIG. 4 shows an example of the transparent conductive film of the present invention, in which the first transparent adhesive layer 6 and the transparent substrate 7 are disposed between the transparent substrate 1 and the hard coat layer 5. Only differs from FIG. The transparent substrate 7 may be composed of a single layer, or may be a laminate of a plurality of transparent films via a transparent adhesive layer (not shown).

  In FIG. 4, a transparent substrate 7 is bonded to the surface of the transparent substrate 1 opposite to the first transparent dielectric layer 2 via a first transparent adhesive layer 6. The transparent substrate 7 may be bonded by providing the first transparent adhesive layer 6 on the transparent substrate 7 and bonding the transparent substrate 1 to the transparent substrate 7, or conversely, the transparent substrate 1 may be bonded to the transparent substrate 1. One transparent adhesive layer 6 may be provided, and a transparent substrate 7 may be bonded thereto.

As the 1st transparent adhesive layer 6, if it has transparency, it can be used without a restriction | limiting in particular, For example, an acrylic adhesive, a silicone adhesive, a rubber adhesive, etc. are used. The first transparent pressure-sensitive adhesive layer 6 has the scratch resistance of the transparent conductive layer 3 provided on one surface of the transparent substrate 1 and the hitting characteristic for a touch panel due to the cushion effect after the transparent substrate 7 is bonded. It has a function to improve more. From the viewpoint of better performing this function, it is desirable to set the elastic modulus in the range of 1 to 100 N / cm ² and the thickness in the range of 1 μm or more, usually 5 to 100 μm.

  The transparent substrate 7 bonded through the first transparent pressure-sensitive adhesive layer 6 imparts good mechanical strength to the transparent substrate 1, and contributes particularly to improvement in the hitting point characteristics due to the cushion effect. A plastic film of about ~ 300 μm is used. When flexibility is not particularly required, a plastic plate of about 0.05 to 10 mm may be used. Examples of the plastic material include the same materials as those of the transparent substrate 1 described above.

  Next, an embodiment of the present invention shown in FIG. 5 will be described. FIG. 5 shows an example of the transparent conductive film of the present invention. The second transparent pressure-sensitive adhesive layer 8 and the release film are formed on the surface of the transparent substrate 1 opposite to the first transparent dielectric layer 2. 1 is different from FIG. 1 only in that 9 is arranged. With this configuration, after peeling off the release film 9 from the transparent conductive film, the transparent conductive film can be bonded to an adherend (not shown) such as a touch panel via the second transparent adhesive layer 8. Therefore, it is possible to provide a transparent conductive film excellent in workability in a previous process (such as a heat treatment process) to be bonded to an adherend.

  As the 2nd transparent adhesive layer 8, the thing similar to the 1st transparent adhesive layer 6 mentioned above can be used. As the release film 9, it is preferable to use, for example, a polyester film in which a migration preventing layer and / or a release layer are laminated on the second transparent adhesive layer 8 side.

  The total thickness of the release film 9 is preferably 30 μm or more, and more preferably in the range of 60 to 100 μm. Deformation of the second transparent pressure-sensitive adhesive layer 8 that is assumed to occur due to foreign matter or the like entering between the rolls when the release film 9 is provided on the second transparent pressure-sensitive adhesive layer 8 and then stored in a roll state. This is for suppressing (dentation).

  The migration preventing layer can be formed of an appropriate material for preventing migration of a migration component in the plastic film, particularly a low molecular weight oligomer component. As a material for forming the migration prevention layer, an inorganic material, an organic material, or a composite material thereof can be used. The thickness of the migration preventing layer can be appropriately set within a range of 0.01 to 20 μm. The method for forming the migration preventing layer is not particularly limited, and for example, a coating method, a spray method, a spin coating method, an in-line coating method, or the like is used. Further, a vacuum deposition method, a sputtering method, an ion plating method, a spray pyrolysis method, a chemical plating method, an electroplating method, or the like can also be used.

  The release layer can be formed of a suitable release agent such as silicone, long chain alkyl, fluorine, molybdenum sulfide. The thickness of the release layer can be appropriately set from the viewpoint of the release effect. In general, from the viewpoint of handleability such as flexibility, the thickness is preferably 20 μm or less, more preferably in the range of 0.01 to 10 μm, and in the range of 0.1 to 5 μm. Is particularly preferred. The method for forming the release layer is not particularly limited, and a method similar to the method for forming the migration preventing layer can be employed.

  The transparent conductive film of the present invention is particularly suitable for capacitive and resistive touch panels. Further, the transparent conductive film of the present invention includes, for example, an electrophoresis method, a twist ball method, a thermal rewritable method, a light writing liquid crystal method, a polymer dispersion type liquid crystal method, a guest / host liquid crystal method, a toner display method, and a chromism method. In addition, it can be suitably used for electronic devices such as a flexible display element such as an electric field deposition method.

  As mentioned above, although the suitable example of the transparent conductive film of this invention was demonstrated, this invention is not limited to the said embodiment. For example, at least one layer of the transparent substrate 1 and the transparent substrate 7 may be a decorative film. As the decorative film, a film in which a color or a pattern is formed on one side or both sides of various plastic films having transparency using a known method such as printing can be used.

  Moreover, although not shown in figure, a 2nd transparent base material may be bonded together on the outer surface of a hard-coat layer through a transparent adhesive layer, and it is good also as a transparent conductive laminated body. In this case, a second hard coat layer may be further provided on the outer surface of the second transparent substrate.

  Examples of the present invention will be described below together with comparative examples. In addition, this invention is limited to a following example and is not interpreted.

<Refractive index of each layer>
The refractive index of each layer is indicated on the refractometer by using an Abbe refractometer manufactured by Atago Co., Ltd., with measurement light (wavelength: 589.3 nm) being incident on each measurement surface at 25.0 ° C. Measurement was performed by the prescribed measurement method.

<Thickness of each layer>
The thickness of the transparent substrate was measured with a Mitsutoyo micro gauge thickness gauge. The thickness of the other layers was measured by observing a cross section with a transmission electron microscope H-7650 manufactured by Hitachi, Ltd.

<Hue b ^* Change in value>
The transparent conductive film or transparent conductive laminate was allowed to stand for 750 hours under the conditions of a temperature of 85 ° C. and a humidity of 85%, and the change in hue b ^* value (Δb ^* ) was calculated by the following formula. The hue b ^* value was measured using a spectrophotometer (DOT-3 manufactured by Murakami Color Research Laboratory Co., Ltd.).
Δb ^* = b ^* 1-b ^* 0
b ^* 0: Hue b ^* value before being left b ^* value b ^* 1: Hue b ^* value after being left

<Change in total light transmittance>
Under conditions of a temperature of 85 ° C. and a humidity of 85%, the transparent conductive film or transparent conductive laminate was allowed to stand for 750 hours, and the change in total light transmittance (ΔT) was calculated by the following formula. The total light transmittance was measured using a haze meter (HGM-2DP manufactured by Suga Test Instruments Co., Ltd.) according to JISK-7105.
ΔT = T1-T0
T0: Total light transmittance before leaving T1: Total light transmittance after leaving

<Alkali resistance>
The transparent conductive film or transparent conductive laminate was immersed in a 2 wt% NaOH aqueous solution heated to 50 ° C. for 2 minutes, washed with water and dried, and then the presence or absence of peeling of the transparent conductive layer was visually confirmed.

<Weight average molecular weight>
The weight average molecular weight was measured using gel permeation chromatography (HLC-8120GPC manufactured by Tosoh Corporation) under the following conditions. The weight average molecular weight was calculated in terms of polystyrene.
Data processor: Tosoh GPC-8020
Column: Sample column; manufactured by Tosoh Corporation, G7000H _XL -H + GMH _XL -H + GMH _XL
Column size; each 7.8mmφ × 30cm (total 90cm)
Flow rate: 0.8ml / min
Injection sample concentration: 0.1% by weight
Injection volume: 100 μl
Column temperature: 40 ° C
Eluent: Tetrahydrofuran Detector: Differential refractometer (RI)

<Production Example 1>
A reactor equipped with a stirrer, a thermometer, a dropping funnel and a nitrogen blowing port was charged with 2410 g of methyl isobutyl ketone and heated until it reached 90 ° C. Next, a mixed liquid consisting of 110 g of methacrylic acid, 990 g of styrene, and 33 g of di-t-butyl peroxide was dropped from the dropping funnel over 1 hour. After dripping, it heated up to 120 degreeC and made it react at the same temperature for 12 hours, and the carboxyl group-containing copolymer a was obtained.

<Production Example 2>
In a reactor equipped with a stirrer, a water separator, a thermometer and a nitrogen inlet, 258 g of glycidol (Epiol OH manufactured by NOF Corporation) and tetramethoxysilane partial condensate (manufactured by Tama Chemical Co., Ltd., trade name: methyl silicate, in one molecule The average number of Si was 4) and 1640 g was charged. While stirring under a nitrogen stream, the temperature was raised to 90 ° C., 0.37 g of dibutyltin dilaurate was added as a catalyst, and the mixture was reacted at 90 ° C. During the reaction, methanol was distilled off from the reaction system using a water separator, and the mixture was cooled when the amount reached 90 g. It took 6 hours from the temperature rise to the cooling. After cooling to 50 ° C., the nitrogen inlet and the water separator were removed, the pressure reducing line was connected, and methanol remaining in the system was removed under reduced pressure at 13 kPa for 15 minutes. During this time, 20 g of methanol was removed by vacuum. Thereafter, the flask was cooled to room temperature to obtain a glycidyl group-containing alkoxysilane partial condensate.

<Production Example 3>
The whole amount of the carboxyl group-containing copolymer a obtained in Production Example 1 was charged into a reaction vessel (system temperature: 90 ° C.), then 709 g of methyl isobutyl ketone, 170 g of methanol, and glycidyl group-containing alkoxysilane obtained in Production Example 2. 331 g of partial condensate and 0.70 g of 2-methylimidazole were added and reacted at the same temperature for 7 hours to obtain a resin raw material (1). The resin raw material (1) includes a structural unit represented by the following formula 1 as the structural unit I and a structural unit represented by the following formula 2 as the structural unit II. In the following formula 1, the average of n is 4.

<Production Example 4>
A reactor equipped with a stirrer, a thermometer, a dropping funnel and a nitrogen blowing port was charged with 923 g of methyl isobutyl ketone and heated until reaching 90 ° C. Subsequently, a mixed liquid composed of 401 g of methacrylic acid, 490 g of styrene, 297 g of methyl methacrylate, and 33 g of di-t-butyl peroxide was dropped from the dropping funnel over 1 hour. After dripping, it heated up to 120 degreeC and made it react at the same temperature for 12 hours, and the carboxyl group-containing copolymer b was obtained.

<Production Example 5>
A resin raw material (2) was obtained in the same manner as in Production Example 3 except that the carboxyl group-containing copolymer b obtained in Production Example 4 was used. The structural units I and II of the resin raw material (2) are the same as the structural units I and II of the resin raw material (1), respectively. Further, the resin raw material (2) further includes a structural unit represented by the following formula 3 as the structural unit III.

<Production Example 6>
A reactor equipped with a stirrer, a thermometer, a dropping funnel and a nitrogen blowing port was charged with 2410 g of methyl isobutyl ketone and heated until it reached 90 ° C. Next, a mixed solution consisting of 110 g of methacrylic acid, 401 g of styrene, 495 g of methyl methacrylate, and 33 g of di-t-butyl peroxide was dropped from the dropping funnel over 1 hour. After dripping, it heated up to 120 degreeC and made it react at the same temperature for 12 hours, and obtained the carboxyl group-containing copolymer c.

<Production Example 7>
A resin raw material (3) was obtained in the same manner as in Production Example 3 except that the carboxyl group-containing copolymer c obtained in Production Example 6 was used. The structural units I to III of the resin raw material (3) are the same as the structural units I to III of the resin raw material (2), respectively.

<Production Example 8>
A reactor equipped with a stirrer, a thermometer, a dropping funnel and a nitrogen blowing port was charged with 923 g of methyl isobutyl ketone and heated until reaching 90 ° C. Next, a mixed solution consisting of 42.5 g of methacrylic acid, 170 g of methyl methacrylate and 6.38 g of di-t-butyl peroxide was dropped from the dropping funnel over 1 hour. After the dropwise addition, the temperature was raised to 120 ° C., and the mixture was reacted at the same temperature for 12 hours to obtain a carboxyl group-containing copolymer d.

<Production Example 9>
The whole amount of the carboxyl group-containing copolymer d obtained in Production Example 8 was charged into a reaction vessel (system temperature: 90 ° C.), then 261 g of methyl isobutyl ketone, 121 g of methanol, and glycidyl group-containing alkoxysilane obtained in Production Example 2. 228 g of partial condensate and 0.28 g of 2-methylimidazole were added and reacted at the same temperature for 7 hours to obtain a resin raw material (4). The structural units I and III of the resin raw material (4) are the same as the structural units I and III of the resin raw material (2), respectively. The resin raw material (4) does not contain the structural unit II.

<Production Example 10>
In a four-flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 5 parts by weight of acrylic acid, 100 parts by weight of butyl acrylate, 0.075 parts by weight of 2-hydroxyethyl acrylate, 2, as a polymerization initiator After charging 0.2 ′ part of 2′-azobisisobutyronitrile and 200 parts by weight of ethyl acetate as a polymerization solvent and sufficiently purging with nitrogen, the temperature in the flask was kept at around 55 ° C. while stirring under a nitrogen stream. The polymerization reaction was carried out for 10 hours, and an acrylic polymer solution was prepared. The acrylic polymer had a weight average molecular weight of 2,200,000. With respect to 100 parts by weight of the solid content of the acrylic polymer solution, 0.2 parts by weight of dibenzoyl peroxide (NIPPER BMT manufactured by NOF Corporation) as a peroxide and diglycidylaminomethylcyclohexane (Mitsubishi Gas) as an epoxy crosslinking agent Tetrad C manufactured by Chemical Co., Ltd.) 0.05 parts by weight, trimethylolpropane / tolylene diisocyanate adduct body (coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.) 0.1 parts by weight, and silane coupling agent (Shin-Etsu) Chemical Industry Co., Ltd. KBM403) 0.075 parts by weight were mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (solid content 10.9% by weight).

<Example 1>
(Formation of first transparent dielectric layer)
The resin raw material (1) obtained in Production Example 3 was diluted with methyl ethyl ketone and adjusted to a solid content of 8.0% by weight to prepare a coating solution. The coating solution is applied to one surface of a polyethylene terephthalate film (transparent substrate) having a thickness of 100 μm and a refractive index of 1.66 using a wire bar, and then heated at 150 ° C. for 2 minutes to be cured. A first transparent dielectric layer having a thickness of 150 nm and a refractive index of 1.56 was formed.

(Formation of second transparent dielectric layer)
A siloxane-based thermosetting resin (trade name: Colcoat P, manufactured by Colcoat Co., Ltd.) was diluted with methyl ethyl ketone and adjusted to a solid content of 1.0% by weight to prepare a coating solution. The coating solution was applied onto the first transparent dielectric layer and cured by heating at 150 ° C. for 1 minute to form a second transparent dielectric layer (thickness 30 nm, refractive index 1.45). .

(Formation of transparent conductive layer)
Using a sintered body of a mixture of indium oxide and tin oxide (indium oxide: 97 wt%, tin oxide: 3 wt%) in an atmosphere of 4 × 10 ⁻¹ Pa composed of argon gas 98% and oxygen gas 2% Then, a transparent conductive layer (thickness 20 nm, refractive index 2.00) made of a composite oxide of indium oxide and tin oxide was formed on the second transparent dielectric layer by sputtering.

(Formation of hard coat layer)
30 parts by adding 5 parts by weight of hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) as a photopolymerization initiator to 100 parts by weight of an acrylic / urethane resin (Dainippon Ink Chemical Co., Ltd., Unidic 17-806) A toluene solution diluted to a solid content concentration of% by weight was prepared. This toluene solution was applied to the side of the polyethylene terephthalate film on which the first transparent dielectric layer was not formed using a wire bar, dried at 100 ° C. for 3 minutes, and then accumulated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / A ² cm-thick ultraviolet ray was irradiated to form a 5 μm thick hard coat layer to obtain a transparent conductive film.

<Example 2>
A transparent conductive film was produced in the same manner as in Example 1 except that a 25 μm-thick polyethylene terephthalate film (refractive index: 1.66) was used as the transparent substrate. Next, a polyethylene terephthalate film having a thickness of 125 μm was prepared as a second transparent substrate, and a hard coat layer was formed on one surface thereof in the same manner as in Example 1. Next, the acrylic adhesive solution obtained in Production Example 10 is applied to the side of the second transparent substrate where the hard coat layer is not formed, heated at 155 ° C. for 1 minute, and dried thickness. Formed a 20 [mu] m transparent adhesive layer. The hard-coat layer of the said transparent conductive film was bonded together to the transparent adhesive layer of the obtained film with an adhesive layer, and the transparent conductive laminated body was obtained.

<Example 3>
Example 1 except that the resin material (2) obtained in Production Example 5 was used instead of the resin material (1) to form a first transparent dielectric layer having a thickness of 150 nm and a refractive index of 1.53. A transparent conductive film was obtained in the same manner.

<Comparative Example 1>
A thermosetting resin composed of a melamine resin, an alkyd resin, and an organic silane condensate (by weight ratio, melamine resin: alkyd resin: organosilane condensate = 2: 2: 1) was used. A transparent conductive film was obtained in the same manner as in Example 1 except that 54 first transparent dielectric layers were formed.

<Comparative example 2>
Example 1 except that the resin material (3) obtained in Production Example 7 was used instead of the resin material (1) to form a first transparent dielectric layer having a thickness of 150 nm and a refractive index of 1.52. A transparent conductive film was obtained in the same manner.

<Comparative Example 3>
Example 1 except that the resin material (4) obtained in Production Example 9 was used instead of the resin material (1) to form a first transparent dielectric layer having a thickness of 150 nm and a refractive index of 1.48. A transparent conductive film was obtained in the same manner.

  About the transparent conductive film and transparent conductive laminated body which were obtained by the said Example and comparative example, it evaluated by the evaluation method mentioned above. The results are shown in Table 1.

As shown in Table 1, the transparent conductive film and the transparent conductive laminate of the examples obtained good results for any of the evaluation items. On the other hand, in Comparative Example 1, it was found that Δb ^* greatly increased and yellowing progressed. Further, in Comparative Examples 2 and 3, the alkali resistance deteriorated and peeling occurred.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 1st transparent dielectric material layer 3 Transparent conductive layer 4 2nd transparent dielectric material layer 5 Hard-coat layer 6 1st transparent adhesive layer
7 Transparent substrate 8 Second transparent adhesive layer 9 Release film

Claims (12)

A transparent conductive film having a transparent conductive layer formed on one or both sides of a transparent substrate via a first transparent dielectric layer,
A second transparent dielectric layer disposed between the first transparent dielectric layer and the transparent conductive layer;
The first transparent dielectric layer has a thickness of 5 nm to 1 μm, a structural unit I represented by the following formula i, a structural unit II represented by the following formula ii, and a structural unit III represented by the following formula iii. A copolymer having
The copolymer, the structural units I, when the total of II and III is 100 mol%, the structural unit I, II and III, respectively 5 to 30 mol%, 40 to 95 mol%及Beauty 4 5 A transparent conductive film containing not more than mol%.

[In Formula i, R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a —Z—R ³ group, and Z is a single bond or an alkylene group having 1 to 5 carbon atoms. R ³ is a substituent represented by Formula A,
In the formula ii, R ⁴ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁵ is a hydrogen atom or a monovalent substituent having 1 to 4 carbon atoms, and m is an integer of 0 to 4. Yes,
In the formula iii, R ⁶ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁷ is a monovalent substituent having 1 to 8 carbon atoms,
In Formula A, L ¹ is a divalent linking group, three R ⁸ are each independently an alkyl group having 1 to 8 carbon atoms, and n is an integer of 1 to 20. ]
2. The transparent conductive film according to claim 1, wherein in Formula A, L ¹ is a linking group represented by Formula B below.

[In Formula B, L ² represents a single bond or an alkylene group having 1 to 8 carbon atoms. ]   The transparent conductive film according to claim 1 or 2, wherein the refractive index of the first transparent dielectric layer is 1.50 to 1.65.   The relation n2 ≦ n1 <n3 is satisfied, where n1 is the refractive index of the transparent substrate, n2 is the refractive index of the first transparent dielectric layer, and n3 is the refractive index of the transparent conductive layer. 4. The transparent conductive film according to any one of 3 above. Disposed between said transparent conductive layer and the first transparent dielectric layer, any one of claims 1 to 4, wherein the first transparent dielectric layer and the refractive index have a second transparent dielectric layer different 2. The transparent conductive film according to item 1.   The transparent conductive film according to claim 1, wherein the transparent substrate is a decorative film. The first transparent dielectric layer is provided on one surface of the transparent substrate,
The transparent conductive film according to any one of claims 1 to 6, further comprising one or more transparent substrates bonded to the other surface of the transparent substrate via a first transparent adhesive layer.   The transparent conductive film according to claim 7, wherein at least one layer of the transparent substrate is a decorative film. The first transparent dielectric layer is provided on one surface of the transparent substrate,
The transparent conductive film of any one of Claims 1-8 which further has a release film bonded together through the 2nd transparent adhesive layer in the side farthest from the said transparent conductive layer. The first transparent dielectric layer and the transparent conductive layer are formed on both surfaces of the transparent substrate,
7. The mold according to claim 1, further comprising a release film bonded to a surface of the one transparent conductive layer opposite to the first transparent dielectric layer via a second transparent adhesive layer. The transparent conductive film described in 1.   The touch panel containing the transparent conductive film of any one of Claims 1-8.   The electronic device containing the transparent conductive film of any one of Claims 1-8.

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