JP2019197734A - Conductive film - Google Patents

Abstract

To provide a conductive film having sufficient adhesion even with a thick conductive layer.SOLUTION: A conductive film includes an easy adhesion layer and a conductive layer containing copper, in this order, on one side of a polyester resin film. The easy adhesion layer is a cured film of an adhesive resin composition. When a surface of the easy adhesion layer is measured by an FT-IR measurement, an absorbance ratio (Ab/Ab) is 1.10 or less with regard to absorbance Abat 1410 cmresulting from C=C-H to absorbance Abat 1450 cmresulting from C-H.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive film.

  Conventionally, a conductive film in which a conductive layer is formed on a surface of a resin film such as a PET film by fusing, plating, vapor deposition, or the like on a functional film such as an electromagnetic shielding sheet, a flat panel display, a sensor, or a solar cell. It is used. Cu is frequently used for the conductive layer because of its low electrical resistivity and low cost (Patent Document 1, etc.).

  Generally, since the adhesiveness of the conductive layer containing metal to the resin film is low, a technique for forming a coating film having adhesiveness to the conductive layer between the resin film and the conductive layer has been proposed (for example, Patent Document 2).

JP2015-056321A Japanese Patent No. 5697223

  There is a demand for lowering the resistance of conductive films as part of increasing the functionality of functional elements. Although it is possible to respond to such a demand by increasing the thickness of the conductive layer, the conductive layer having a thick film may peel off from the resin film even if the coating film is provided. It has been found that there is.

  An object of the present invention is to provide a conductive film having sufficient adhesion even with a thick conductive layer.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by adopting the following configuration, and have arrived at the present invention.

That is, the present invention is a conductive film comprising an easy adhesion layer and a conductive layer containing copper in this order on one surface side of a polyester-based resin film,
The easy adhesion layer is a cured film of an adhesive resin composition,
Absorbance ratios for the absorbance _{Ab 1450} at 1450 cm ^-1 due to C-H absorbance _{Ab 1410} at 1410 cm ^-1 attributable to the C = C-H when the surface of the easily adhesion layer was FT-IR measurement _(Ab 1410 _{/ Ab 1450)} relates to a conductive film is 1.10 or less.

  The conductive film includes an easy-adhesion layer that is a cured film of the adhesive resin composition between the polyester resin film and the conductive layer, and a predetermined absorbance ratio by FT-IR measurement of the surface of the easy-adhesion layer. Therefore, sufficient adhesion can be secured even if the conductive layer is a thick film.

Although the mechanism by which the adhesion is improved by controlling the absorbance ratio of the easy-adhesion layer by FT-IR measurement is not clear, it is assumed that the promotion of the crosslinked structure in the easy-adhesion layer and the improvement of the film strength based on this are one factor. Is done. From the relationship between the absorbance ratio at FT-IR measurement, the absorbance _{Ab 1410} at 1410 cm ^-1 attributable to the C = C-H, as will become smaller than the absorbance _{Ab 1450} at 1450 cm ^-1 due to C-H It is controlled. Since the absorbance is in a certain proportional relationship with the amount of binding present, the decrease in absorbance Ab _{1410 at 1410} cm ⁻¹ means that the amount of C═C—H bonds attributed to that peak is small. It corresponds to becoming. In the process of forming the easy adhesion layer, the C═C double bond in the C═C—H bond is combined with other C═C double bonds in the system through radical addition reaction to form a kind of cross-linked structure. As a result, the crosslinked structure in the easy adhesion layer is promoted. Since the C═C double bond is cleaved and consumed to form a crosslinked structure means that the abundance of the C═C—H bond is reduced, the present invention is based on such a correlation. A predetermined absorbance ratio is defined.

  Furthermore, when the cross-linking structure in the easy adhesion layer is promoted, the film internal structure which has been loosened until then becomes strong, and the film strength is improved. It is speculated that such an improvement in film strength contributes to an improvement in adhesion. That is, as the thickness of the conductive layer increases, the internal stress in the conductive layer increases, and the stress generated between the conductive layer and the easy adhesion layer also increases. The conventional easy adhesion layer cannot resist the increase in stress in the conductive layer, and causes film breakage or peeling at the interface between the conductive layer and the easy adhesion layer (hereinafter also referred to as “interfacial peeling”). On the other hand, since the conductive film includes an easy-adhesion layer having a crosslinked structure promoted and an increased film strength, film breakage and interfacial peeling of the easy-adhesion layer are suppressed, and good adhesion can be exhibited.

  The wetting tension on the surface of the easy adhesion layer is preferably 45 dyn / cm or less. By setting the surface wetting tension of the easy adhesion layer within the above range, the surface free energy of the easy adhesion layer is lowered, in other words, the easy adhesion layer is easily wetted with respect to the conductive layer, and adheres to the conductive layer containing copper. The sex can be further improved.

  The adhesive resin composition preferably contains at least one of a (meth) acrylate monomer and a (meth) acrylate oligomer. Thereby, formation of the crosslinked structure resulting from the C = C double bond contained in the acryloyl group is facilitated, and the film strength can be efficiently improved.

  The adhesive resin composition preferably has ultraviolet curable properties. As a result, it is possible to promote the formation of a crosslinked structure by simply irradiating ultraviolet rays while avoiding thermal damage to the polyester resin film and conductive layer in the case of heat curing, so that the conductive structure can be stably and efficiently conducted. An adhesive film can be formed.

  The easy adhesion layer preferably has a thickness of 0.2 μm to 2.0 μm. By setting the thickness of the easy adhesion layer in the above range, the adhesion can be exhibited at a higher level.

  The conductive layer may have a thickness of 2 nm to 2500 nm. Even when the thickness of the conductive layer is within the above range, the conductive film has a specific easy-adhesion layer, so that the adhesion of the conductive layer can be ensured.

  An antiblocking layer may be provided on the other surface side of the polyester resin film.

It is typical sectional drawing of the electroconductive film which concerns on one Embodiment of this invention.

  Embodiments of the conductive film of the present invention will be described below with reference to the drawings. However, in some or all of the drawings, parts unnecessary for the description are omitted, and there are parts shown enlarged or reduced for easy explanation. The terms indicating the positional relationship such as up and down are merely used for ease of explanation, and are not intended to limit the configuration of the present invention.

<Conductive film>
FIG. 1 is a schematic cross-sectional view of a conductive film according to an embodiment of the present invention. A conductive film 10 shown in FIG. 1 includes an easy adhesion layer 2 and a conductive layer 3 in this order on one surface side of a polyester-based resin film 1. The easy adhesion layer 2 and the conductive layer 3 each have a single-layer configuration, but each may have a multilayer configuration of two or more layers. Further, an anti-blocking layer 4 may be provided on the other surface side of the polyester resin film 1.

(Polyester resin film)
The polyester resin film (hereinafter also simply referred to as “resin film”) is not particularly limited as long as it is a film formed of a polyester resin. Examples of the material include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). In addition, unless the effects of the present invention are impaired, polyimide resins such as polyimide (PI), polyolefin resins such as polyethylene (PE) and polypropylene (PP), acetate resins, polyethersulfone resins, polycarbonate resins Polyamide resin, cycloolefin resin, (meth) acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin, etc. May be. Among these, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferable from the viewpoints of heat resistance, durability, flexibility, production efficiency, cost, and the like. In particular, polyethylene terephthalate (PET) is preferable from the viewpoint of cost performance.

  The surface of the resin film is subjected to etching treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, and undercoating treatment, and adhesion to the easy adhesion layer formed on the resin film. You may make it improve. Further, before forming the easy-adhesion layer, the resin film surface may be dedusted and cleaned by solvent cleaning or ultrasonic cleaning as necessary.

  Although the thickness of the resin film is not particularly limited, it is preferably in the range of 2 to 200 μm, more preferably in the range of 10 to 100 μm, and still more preferably in the range of 20 to 60 μm. In general, a thicker resin film is desirable in that heat shrinkage during heating can be suppressed and adhesion of the conductive layer can be maintained. However, it is desirable to reduce the thickness of the resin film to some extent due to downsizing of electronic parts and the like. On the other hand, when the thickness of the resin film is too thin, the handling property of the conductive film is lowered. Furthermore, when the thickness of the resin film is within the above range, the resin film has sufficient mechanical strength while ensuring the flexibility of the resin film, and the film is rolled to continuously form an easy adhesion layer, a conductive layer, and the like. Can be operated.

(Easily adhesive layer)
The easy adhesion layer 2 is a cured film of the adhesive resin composition. 1410 cm ⁻ caused by C═C—H when FT-IR measurement is performed on the surface of the easy adhesion layer 2 opposite to the resin film 1 side (hereinafter also simply referred to as “surface of the easy adhesion layer”). absorbance ratios for the absorbance _{Ab 1450} at 1450 cm ^-1 due to C-H absorbance _{Ab 1410} at ¹ _(Ab 1410 _/ Ab ₁₄₅₀₎ is 1.10 or less. The absorbance ratio is more preferably 1.08 or less. By setting the absorbance ratio within a specific range, sufficient adhesion can be ensured even if the conductive layer is a thick film. On the other hand, when the cross-linking structure is excessively formed in the easy-adhesion layer, the easy-adhesion layer becomes brittle and the adhesiveness is lowered, or the adhesive resin composition for forming the easy-adhesion layer has ultraviolet curing properties In addition, when the ultraviolet rays are excessively irradiated, the resin film may be deteriorated. From the viewpoint of preventing these, the absorbance ratio is preferably 0.93 or more, and more preferably 1.0 or more.

  The surface tension of the easy-adhesion layer 2 is preferably 45 dyn / cm or less, more preferably 44 dyn / cm or less, and still more preferably 40 dyn / cm or less. By setting the wetting tension of the surface of the easy adhesion layer 2 within the above range, the surface free energy can be reduced, and the adhesion with the conductive layer can be further improved. The wetting tension is preferably 35 dyn / cm or more.

  As the adhesive resin composition, those having sufficient adhesiveness and strength as a cured film after the formation of the easy adhesion layer can be used without particular limitation. Examples of the resin to be used include thermosetting resins, thermoplastic resins, ultraviolet curable resins, electron beam curable resins, two-component mixed resins, and mixtures thereof. Among these, curing treatment by ultraviolet irradiation is possible. Therefore, an ultraviolet curable resin capable of efficiently forming an easy adhesion layer by a simple processing operation is preferable. By including an ultraviolet curable resin, an adhesive resin composition having ultraviolet curable properties can be easily obtained.

  The adhesive resin composition preferably contains at least one of a (meth) acrylate monomer and a (meth) acrylate oligomer. Thereby, formation of the crosslinked structure resulting from the C = C double bond contained in the acryloyl group is facilitated, and the film strength can be efficiently improved. In the present specification, (meth) acrylate means acrylate or methacrylate.

  The (meth) acrylate monomer and / or acrylate oligomer having a (meth) acryloyl group as a main component used in this embodiment has a role of forming a coating film, specifically, trimethylolpropane tri (meth) acrylate. , Ethylene oxide modified trimethylolpropane tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, trimethylolpropane tetra (meth) acrylate, tris (acryloxyethyl) isocyanurate, caprolactone modified tris (acryloxyethyl) ) Isocyanurate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipenta Lithritol hexa (meth) acrylate, alkyl-modified dipentaerythritol tri (meth) acrylate, alkyl-modified dipentaerythritol tetra (meth) acrylate, alkyl-modified dipentaerythritol penta (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) Examples include acrylates and mixtures of two or more of these.

  Among the above (meth) acrylates, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, or a mixture thereof is preferable in terms of wear resistance and curability. Especially preferred.

  A urethane acrylate oligomer can also be used. The urethane (meth) acrylate oligomer is a method in which a polyol and a polyisocyanate are reacted and then a method of reacting a (meth) acrylate having a hydroxyl group, or after reacting a polyisocyanate and a (meth) acrylate having a hydroxyl group. And a method of reacting a polyol and a method of reacting a polyisocyanate, a polyol, and a (meth) acrylate having a hydroxyl group are not particularly limited.

  Examples of the polyol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol and copolymers thereof, ethylene glycol, propylene glycol, 1,4-butanediol, 2,2′-thiodiethanol and the like.

  Examples of the polyisocyanate include isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4′- Examples include diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate.

If the crosslinking density is too high, the performance as a primer is lowered, and the metal adhesion tends to be lowered. Therefore, a low-functional (meth) acrylate having a hydroxyl group (hereinafter referred to as a hydroxyl group-containing (meth) acrylate) may be used. Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, and the like. . The (meth) acrylate monomer component and / or (meth) acrylate oligomer component described above may be used alone or in combination of two or more.

It is preferable that the adhesive resin composition having ultraviolet curing property of the present embodiment includes a thiourea type silane coupling agent as the silane coupling agent. Thereby, the adhesive force as a primer of a conductive layer improves. A thiourea type silane coupling agent is an alkoxysilane coupling agent having a structure represented by the following general formula (1), and as commercially available products, X-12-1016M, X-12-1111, X-12-1116, X -121-1117 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.).

  Furthermore, antiblocking property improves by mix | blending a (meth) acryl group containing silane coupling agent. Examples of the (meth) acrylic group-containing silane coupling agent include 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, Examples include 3-methacryloxypropyltriethoxysilane, and commercially available products include KR-513 and KBM-5103 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.).

  When the thiourea type silane coupling agent and the (meth) acrylic group-containing silane coupling agent are used in combination, the (meth) acrylic group-containing silane coupling agent is 50 to 150 parts by weight with respect to 100 parts by weight of the thiourea type silane coupling agent. Is preferred.

  The compounding amount of the silane coupling agent is 0.1 to 50 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the (meth) acrylate monomer and / or (meth) acrylate oligomer. . Within this range, the adhesion with the conductive layer is improved and the physical properties of the coating film can be maintained.

  The easy-adhesion layer 2 of this embodiment may contain nano silica fine particles. As the nanosilica fine particles, organosilica sol synthesized from alkylsilane or nanosilica synthesized by plasma arc can be used. Commercially available products include PL-7-PGME (manufactured by Fuso Chemical, trade name) for the former, and SIRMIBK15WT% -M36 (trade name, manufactured by CIK Nanotech) for the latter. The blending ratio of the nano silica fine particles is preferably 5 to 30 parts by weight with respect to 100 parts by weight of the total weight of the (meth) acrylate monomer and / or acrylate oligomer having the (meth) acryloyl group and the silane coupling agent. Part by weight is more preferred. By setting it to the lower limit or more, surface unevenness can be formed and anti-blocking properties can be imparted, and roll-to-roll production becomes possible. By making the upper limit or less, it is possible to prevent a decrease in adhesion with the conductive layer.

  The average particle size of the nanosilica fine particles is preferably 100 to 500 nm. If the average particle size is less than 100 nm, the amount of addition necessary to form irregularities on the surface increases, so that adhesion to the conductive layer cannot be obtained, whereas if it exceeds 500 nm, the haze increases and the visibility decreases. Problems occur.

  The adhesive resin composition preferably contains a photopolymerization initiator in order to impart ultraviolet curability. Photopolymerization initiators include benzoin ethers such as benzoin normal butyl ether and benzoin isobutyl ether, benzyl ketals such as benzyl dimethyl ketal and benzyl diethyl ketal, and acetophenones such as 2,2-dimethoxyacetophenone and 2,2-diethoxyacetophenone. 1-hydroxycyclohexyl phenyl ketone, [2-hydroxy-2-methyl-1- (4-ethylenephenyl) propan-1-one], 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1- (4-isopropylphenyl) propane-1- Α-Hydroxyalkylpheno such as ON , Α-amino such as 2-methyl-1- [4- (methylthio) phenyl] -1-morpholinopropane, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone Alkylphenones, monoacylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4, And monoacylphosphine oxides such as 4-trimethylpentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide.

  From the viewpoints of resin curability, light stability, compatibility with resin, low volatility, and low odor, alkylphenone photopolymerization initiators are preferred, such as 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1 -Phenyl-propan-1-one, (2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 1 -[4- (2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one is more preferable, and Irgacure 127, 184, 369, 651, 500, 891, 907 are commercially available products. 2959, Darocur 1173, TPO (trade name, manufactured by BASF Japan Ltd.), etc. The photopolymerization initiator is ( Data) with respect to 100 parts by weight having an acryloyl group (meth) acrylate monomer and / or acrylate oligomer is blended solids 3-10 parts by weight.

  When forming the easy adhesion layer, an adhesive resin composition mainly composed of (meth) acrylate and / or (meth) acrylate oligomer having (meth) acryloyl group in the molecule is added to toluene, butyl acetate, Diluted in a solvent such as butanol, ethyl acetate, cyclohexane, cyclohexanone, methylcyclohexanone, hexane, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, diethyl ether, ethylene glycol, and prepared as a varnish with a solid content of 30-50% To do.

  The easy adhesion layer 2 is formed by applying the varnish on the polyester resin film 1. The varnish application method can be selected in a timely manner according to the conditions of the varnish and the coating process. For example, dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method, die coating It can be applied by a method or an extrusion coating method.

An easy-adhesion layer can be formed by hardening a coating film after apply | coating a varnish. As the curing treatment of the adhesive resin composition having ultraviolet curable properties, when the varnish contains a solvent, the solvent is removed by drying (for example, at 80 ° C. for 1 minute), and then 500 mW / cm ^{2 to} 3000 mW / using an ultraviolet irradiator. in the irradiation intensity of cm ^2, the amount of work steps and the like that are cured with ultraviolet processing 50~400mJ / cm ^2. An ultraviolet lamp is generally used as an ultraviolet ray generation source. Specifically, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a metal halide lamp, and the like can be mentioned. It may be in an inert gas such as nitrogen or argon.

  Heating is preferably performed during the ultraviolet curing process. The curing reaction of the adhesive resin composition proceeds by ultraviolet irradiation, and at the same time, a crosslinked structure is formed. By heating at this time, formation of a crosslinked structure can be sufficiently promoted even with a low ultraviolet ray amount, and a desired absorbance ratio can be achieved efficiently. The heating temperature can be set according to the degree of crosslinking, and is preferably 50 ° C to 80 ° C. A heating means is not specifically limited, A warm air dryer, a radiant heat dryer, the heating of a film conveyance roll, etc. can be employ | adopted suitably.

  The thickness of the easy adhesion layer is not particularly limited, but is preferably 0.2 μm to 2.0 μm, more preferably 0.5 μm to 1.5 μm, and further preferably 0.8 μm to 1.2 μm. preferable. By setting the thickness of the easy adhesion layer in the above range, the adhesion can be exhibited at a higher level.

(Conductive layer)
The conductive layer is preferably formed directly on the easy adhesion layer formed on at least one surface side of the resin film. The electrical resistivity of the conductive layer may be appropriately set according to the application. For example, the electrical resistivity is preferably 50 μΩcm or less in order to sufficiently obtain an electromagnetic wave shielding effect and a sensor function. As a constituent material of the conductive layer, copper (Cu) may be included. Copper has high conductivity that contributes to electromagnetic shielding characteristics and sensor function, is relatively inexpensive, and has excellent cost performance and production efficiency. Elements other than Cu may be contained to the extent of impurities. For example, Fe, Cr, Ti, Si, Nb, In, Zn, Sn, Au, Ag, Co, Cr, Ni, Pb, Pd, Pt, W, Examples include metals such as Zr, Ta, Hf, Mo, Mn, Mg, and V. Moreover, the thing containing 2 or more types of these metals, the alloy which has these metals as a main component, etc. can be used. Thereby, since the electrical resistivity is sufficiently small and the conductivity is high, the electromagnetic wave shielding characteristics and the sensor function can be improved.

  The formation method of a conductive layer is not specifically limited, A conventionally well-known method is employable. Specifically, for example, from the viewpoint of film thickness uniformity and film formation efficiency, vacuum film formation methods such as sputtering, chemical vapor deposition (CVD), and physical vapor deposition (PVD), and ion plating are used. The film is preferably formed by a plating method, a plating method (electrolytic plating, electroless plating), a hot stamp method, a coating method, or the like. Moreover, you may combine several of these film forming methods, and can also employ | adopt an appropriate method according to the required film thickness. Of these, the sputtering method and the vacuum film forming method are preferable, and the sputtering method is particularly preferable. Thereby, it is possible to continuously produce by a roll-to-roll manufacturing method, increase production efficiency, and control the film thickness at the time of film formation, so that an increase in the surface resistance value of the conductive film can be suppressed. In addition, a dense conductive layer that is thin, has a uniform thickness, and can be formed.

  The thickness of the conductive layer is preferably 2 to 2500 nm, more preferably 5 to 2000 nm, and still more preferably 10 to 1500 nm. When the thickness of the conductive layer is within the above range, curling of the conductive film after heating can be suppressed, and a reduction in resistance can be achieved. Further, the production efficiency at the time of film formation increases, the integrated heat amount at the time of film formation decreases, and heat wrinkles are less likely to occur on the film.

(Protective layer)
A protective layer may be formed on the outermost surface side (the side opposite to the resin film side) of the conductive layer. It is possible to prevent the conductive layer from being naturally oxidized under the influence of oxygen in the atmosphere. The protective layer is not particularly limited as long as it exhibits the effect of preventing rust of the conductive layer, but is preferably a metal that can be sputtered, such as Ni, Cu, Ti, Si, Zn, Sn, Cr, Fe, indium, gallium, antimony, zirconium. Any one or more metals selected from the group consisting of magnesium, aluminum, gold, silver, palladium, and tungsten, or oxides thereof are used. Ni, Cu, and Ti are hardly corroded because they form a passive layer, Si is hard to be corroded because corrosion resistance is improved, and Zn and Cr are metals that are not easily corroded because they form a dense oxide film on the surface. preferable.

  As a material for the protective layer, an alloy composed of two kinds of metals can be used from the viewpoint of improving the adhesion with the conductive layer and surely preventing the rust of the conductive layer, but composed of three or more kinds of metals. Alloys are preferred. Examples of the alloy composed of three or more kinds of alloys include Ni—Cu—Ti, Ni—Cu—Fe, and Ni—Cu—Cr. From the viewpoint of rust prevention function and production efficiency, Ni—Cu—Ti is preferable. preferable. In addition, it is preferable that it is an alloy containing a conductive layer from a viewpoint of improving adhesiveness with a conductive layer. Thereby, the oxidation of the conductive layer can be surely prevented.

  Examples of the material for the protective layer include indium-doped tin oxide (ITO), tin oxide containing antimony (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), and indium-doped zinc oxide ( IZO) may be included. In addition to suppressing an increase in the initial surface resistance value of the conductive film, it is possible to suppress an increase in the surface resistance value under humidified heat conditions and to optimize the stabilization of the surface resistance value, which is preferable.

  The metal oxide is preferably an oxide such as SiOx (x = 1.0 to 2.0), copper oxide, silver oxide, titanium oxide, etc., from the viewpoint of stabilizing the surface resistance value of the conductive film. SiOx (x = 1.0 to 2.0) is particularly preferable. Thereby, a conductive layer becomes difficult to be corroded. In addition, it is also possible to bring about a rust prevention effect by forming a resin layer such as an acrylic resin or an epoxy resin on the conductive layer instead of the aforementioned metal, alloy, oxide or the like.

  1-50 nm is preferable, as for the film thickness of a protective layer, 2-30 nm is more preferable, and 3-20 nm is preferable. Thereby, since durability can be improved and oxidation can be prevented from the surface layer, an increase in the surface resistance value under humidified heat conditions can be suppressed.

(Anti-blocking layer)
An anti-blocking layer 4 is provided on the side of the polyester-based resin film 1 opposite to the easy-adhesion layer 2 side in order to prevent blocking between films and enable production by a roll-to-roll method. Also good.

  For the formation of the anti-blocking layer 4, a material obtained by adding particles to the same adhesive resin composition as that of the easy adhesion layer 2 can be suitably used. By blending the particles, irregularities can be formed on the surface of the antiblocking layer 4, and the antiblocking property can be suitably imparted to the conductive film 10.

  As said particle | grains, what has transparency, such as various metal oxides, glass, a plastics, can be especially used without a restriction | limiting. For example, inorganic particles such as silica, alumina, titania, zirconia, calcium oxide, polymethyl methacrylate, polystyrene, polyurethane, acrylic resin, acryl-styrene copolymer, benzoguanamine, melamine, polycarbonate, or other cross-linked or uncrosslinked polymers. Examples include crosslinked organic particles and silicone particles. One kind or two or more kinds of the particles can be appropriately selected and used.

  The average particle size and blending amount of the particles can be appropriately set in consideration of surface roughness and haze. As an average particle diameter, 0.5 micrometer-2.0 micrometers are preferable, and as a compounding quantity, 0.2-5.0 weight part is preferable with respect to 100 weight part of solid content of a resin composition.

  The thickness of the conductive film of the present embodiment is preferably in the range of 2 to 200 μm, more preferably in the range of 10 to 100 μm, similarly to the resin film, and in the range of 20 to 60 μm. More preferably. Thereby, the electroconductive film itself can also be made thin and it becomes possible to suppress the thickness at the time of using for an electromagnetic wave shield sheet, a sensor, etc. Therefore, it can respond to thickness reduction of an electromagnetic wave shield sheet, a sensor, etc. Furthermore, when the thickness of the conductive film is within the above range, the mechanical strength can be sufficient while ensuring flexibility, and the easy-adhesion layer, the conductive layer, etc. are continuously formed in a roll shape. Operation to form becomes easy and production efficiency improves.

(Use of conductive film)
The conductive film of this embodiment can be applied to various uses, and can be applied to, for example, an electromagnetic wave shield sheet, a planar sensor, and the like. The electromagnetic wave shielding sheet uses a conductive film and can be suitably used in the form of a touch panel or the like. The thickness of the electromagnetic wave shielding sheet is preferably 20 μm to 300 μm.

  The shape of the electromagnetic wave shielding sheet is not particularly limited, and the shape seen from the stacking direction (the same direction as the thickness direction of the sheet) is a square shape, a circular shape, a triangular shape, a polygonal shape, depending on the shape of the object to be installed. An appropriate shape such as a shape can be selected.

  The surface sensor uses a conductive film. The user interface such as a touch panel of a mobile device or a controller has a force sensor for measuring a load, a sensing area of an object, for example, an outer surface of an automobile, a robot or a doll. It includes sensors that sense various physical quantities such as external forces applied to the surface. The planar sensor can be suitably used in the form of a force sensor, a shield, or the like. The thickness of the planar sensor is preferably 20 μm to 300 μm.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded. In the examples, unless otherwise indicated, “parts” means “parts by weight”.

<Example 1>
(Formation of easy adhesion layer)
A PET film is drawn out from a wound body of a polyethylene terephthalate film having a thickness of 100 μm (trade name “Lumirror # 100-U40” manufactured by Toray Industries, Inc., hereinafter referred to as a PET film), and an adhesive resin having ultraviolet curable properties on one side thereof. After applying a composition (“Z-844-2L” manufactured by Aika Kogyo Co., Ltd.) and drying at 80 ° C. for 1 minute, an ozone type high-pressure mercury lamp (15 cm condensing type, UV intensity 16 W / cm ² , integrated) (Light quantity: 200 mJ / cm ² ) was irradiated with ultraviolet rays to form an easy adhesion layer having a thickness of 1.5 μm. The surface temperature of the film transport roll during UV irradiation was set to 50 ° C., and UV curing was performed while heating.

(Formation of conductive layer)
Next, the roll which wound up the elongate resin film in which the easily bonding layer was formed on PET film was installed in the sputtering device. Next, the resin film is fed out at a film feed speed of 2 m / min, and is sintered by DC magnetron sputtering using a Cu target material in an atmosphere of 3.0 × 10 ⁻³ Torr consisting of 100% by volume of Ar gas. A conductive layer (Cu layer) was formed with a thickness of 200 nm on the easy adhesion layer, and finally the film was wound to prepare a wound body of the conductive film.

<Example 2>
A conductive film roll was prepared in the same manner as in Example 1 except that the surface temperature of the film transport roll during UV irradiation was 75 ° C., and UV curing was performed while heating.

<Example 3>
A conductive film roll was prepared in the same manner as in Example 1 except that the surface temperature of the film transport roll during UV irradiation was set to 100 ° C. and UV curing was performed while heating.

<Example 4>
A conductive film roll was prepared in the same manner as in Example 1 except that the surface temperature of the film transport roll during UV irradiation was 125 ° C., and UV curing was performed while heating.

<Comparative Example 1>
A conductive film roll was prepared in the same manner as in Example 1 except that the surface temperature of the film transport roll during UV irradiation was 25 ° C. and UV curing was performed at room temperature.

<Evaluation>
The following evaluation was performed about the produced easily-adhesion layer and electroconductive film. The results are shown in Table 1.

(1) Measurement of thickness The thickness of less than 1 μm was measured by observing the cross section of the conductive film using a transmission electron microscope (product name “H-7650” manufactured by Hitachi, Ltd.). The thickness of 1 μm or more was measured using a film thickness meter (Peacock Co., Digital Dial Gauge DG-205).

(2) FT-IR measurement About the easy-adhesion layer formed on the PET film, the reflection method (ATR method), wave number 500cm < ^-1 > -4000cm using the FT-IR measuring apparatus (The Parkin Elmer company make, "Frontier"). ⁻¹ , a resolution of 1.0 cm ⁻¹ , and an infrared absorption spectrum were measured at 10 integrations. From the obtained spectrum, C = C-H read the absorbance _{Ab 1450} in absorbance _{Ab 1410,} and 1450 cm ^-1 due to C-H in due to 1410 cm ^-1, they from the absorbance ratio _(Ab 1410 / Ab ₁₄₅₀ ).

(3) Adhesion evaluation A 10 mm × 10 mm size was cut out from the conductive film, and the thickness of the conductive layer (Cu layer) was increased to 2 μm by plating. Adhesion evaluation was performed by a cross-cut method based on JIS-K-5600 using a conductive film having a thick conductive layer as a measurement sample. Make a total of 100 square grids by cutting 11 cuts at 1 mm intervals on the conductive layer surface with a cutter knife, etc., and make a tape of about 75 mm on the grid pattern. (Registered Trademark) (trade name “610-1PK” manufactured by 3M Co., Ltd.) is attached, and then the end of the tape is grasped and peeled in the direction of 60 ° in a time of 0.5 to 1.0 seconds, and the conductive layer is peeled off Was evaluated by visual confirmation. The case where 90 or more squares remained in the conductive layer was evaluated as “◯”, and the case where it was less than 90 was evaluated as “x”.

(4) Wetting tension measurement Measured according to JIS-K-6768. A Wako Pure Chemicals wetting tension test mixture was used.

(Results and discussion)
In the conductive films of the examples, the adhesiveness of the conductive layer was good. On the other hand, in Comparative Example 1, many grids of the conductive layer were peeled off, and the adhesion was reduced. This is presumed to be due to the fact that the cross-linking structure in the easy-adhesion layer was insufficient and the film strength was low because heating was not performed when the easy-adhesion layer was cured with ultraviolet light.

1 Polyester resin film 2 Easy adhesion layer 3 Conductive layer 4 Anti-blocking layer

Claims (7)

On one surface side of the polyester-based resin film, a conductive film provided with an easy adhesion layer and a conductive layer containing copper in this order,
The easy adhesion layer is a cured film of an adhesive resin composition,
Absorbance ratios for the absorbance _{Ab 1450} at 1450 cm ^-1 due to C-H absorbance _{Ab 1410} at 1410 cm ^-1 attributable to the C = C-H when the surface of the easily adhesion layer was FT-IR measurement _(Ab 1410 _{/ Ab 1450)} is 1.10 or less conductive film.   The conductive film according to claim 1, wherein the surface of the easy adhesion layer has a wetting tension of 45 dyn / cm or less.   The conductive film according to claim 1, wherein the adhesive resin composition contains at least one of a (meth) acrylate monomer and a (meth) acrylate oligomer.   The conductive film according to claim 1, wherein the adhesive resin composition has ultraviolet curable properties.   The conductive film according to claim 1, wherein the easy adhesion layer has a thickness of 0.2 μm to 2.0 μm.   The conductive film according to claim 1, wherein the conductive layer has a thickness of 2 nm to 2500 nm. The conductive film according to claim 1, further comprising an anti-blocking layer on the other surface side of the polyester resin film.

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