JP7280036B2 - METHOD FOR MANUFACTURING CONDUCTIVE FILM - Google Patents

Description

The present invention relates to a method for producing a conductive film.

Conventionally, conductive films in which conductive layers are formed on both sides of a resin film have been used in flexible circuit boards, electromagnetic wave shielding films, flat panel displays, touch sensors, non-contact IC cards, solar cells, etc. Reference 1). The main function of the conductive film is electrical conduction, and the composition and thickness of the conductive layer provided on the surface of the polymer film are appropriately selected so as to obtain electrical conductivity suitable for the purpose of use.

Japanese Unexamined Patent Application Publication No. 2011-82848

2. Description of the Related Art In order to improve the functionality of recent devices and expand their applications, it is sometimes required to reduce the resistance of conductive layers. In general, lowering the resistance of the conductive layers can be achieved by increasing the thickness of at least one of the conductive layers. However, when a thick conductive layer is formed by a sputtering method, the resin film may be wrinkled, which is one of the causes of reduced productivity and reliability.

An object of the present invention is to provide a method for producing a conductive film capable of suppressing the occurrence of wrinkles in a resin film even when forming a relatively thick conductive layer.

The present inventors have made intensive studies to solve the above problems, and have found that the above objects can be achieved by adopting the following configuration, and have completed the present invention.

The present invention, in one embodiment,
Step A of forming a first conductive layer on one surface of the resin film;
A step B of bonding a protective film onto the first conductive layer, and a step C of forming a second conductive layer having a thickness of 80 nm or more and 300 nm or less on the other surface of the resin film by a sputtering method while extending the resin film.
It relates to a method for producing a conductive film containing.

In this manufacturing method, a protective film is attached to a first conductive layer formed on one surface of a resin film, and then a thick second conductive layer is formed on the other surface of the resin film. In other words, the protective film functions as a reinforcing material for the resin film during the formation of the second conductive layer, thereby suppressing wrinkles in the resin film.

Preferably, in the step A, the first conductive layer is formed by a sputtering method. A homogeneous conductive layer can be efficiently formed. In addition, the process A to process C can be continuously performed by a roll-to-roll method, and the yield can be improved.

It is preferable that the thickness of the first conductive layer is 80 nm or more and 300 nm or less. As a result, both sides can be formed as thick conductive layers, and the conductive film can be made to have low resistance and high functionality.

It is preferable that the protective film has a thickness of 20 μm or more and 200 μm or less. By setting the thickness of the protective film within this range, it is possible to exhibit sufficient resin film reinforcing properties while maintaining handleability.

In the step C, the total power density represented by the following formula in the sputtering method is preferably 1500 kW/m ² or less.
Total power density = N x T x P
(In the formula, N is the number of process repetitions, T is the number of targets per process, and P is the power density [kW/m ² ] per target.)

By setting the total power density at the time of sputtering in step C to a predetermined value or less, the load on the resin film is reduced, and the occurrence of wrinkles can be suppressed at a higher level. Also, in order to form a thick conductive layer, it is possible to employ a procedure in which sputtering is performed a few times at high power density, or a procedure in which sputtering is performed many times at low power density. In any procedure, by controlling the total power density obtained by the above formula within a predetermined range, it is possible to produce a conductive film with good production efficiency while suppressing wrinkles in the resin film.

In the step C, it is preferable that the resin film has a tensile stress of 1 MPa or more in the MD direction. By applying a predetermined tensile stress in the MD direction to the resin film when forming the second conductive layer, it is possible to further reduce the occurrence of wrinkles in the resin film.

1 is a schematic cross-sectional view of a conductive film according to one embodiment of the present invention; FIG. It is a conceptual diagram explaining the structure of the vacuum film-forming apparatus which concerns on one Embodiment of this invention.

EMBODIMENT OF THE INVENTION Embodiment of the manufacturing method of the electroconductive film of this invention is described below, referring drawings. However, in some or all of the drawings, parts that are not necessary for explanation are omitted, and some parts are enlarged or reduced in order to facilitate explanation. Terms indicating positional relationships such as top and bottom are used merely for the sake of facilitating the description, and are not intended to limit the configuration of the present invention.

<<First embodiment>>
<Method for producing conductive film>
The method for producing a conductive film according to the present embodiment includes a step A of forming a first conductive layer on one surface of a resin film, a step B of bonding a protective film on the first conductive layer, and a step B of bonding the resin film. A step C of forming a second conductive layer having a thickness of 80 nm or more and 300 nm or less on the other surface of the resin film by a sputtering method while the resin film is extended.

FIG. 1 is a schematic cross-sectional view of a conductive film obtained by the method for producing a conductive film of this embodiment. The conductive film 100 shown in FIG. (Hereinafter, when the first conductive layer and the second conductive layer are not distinguished, they may simply be referred to as “conductive layers”.). Furthermore, in the present embodiment, the first protective film 31 is arranged on the side of the first conductive layer 21 opposite to the resin film 1, and the second protective film 32 is arranged on the side of the second conductive layer 22 opposite to the resin film 1. (Hereinafter, when the first protective film and the second protective film are not distinguished, they may simply be referred to as “protective films”.).

<<Process A>>
In step A, the first conductive layer 21 is formed on one surface of the resin film 1 .

(resin film)
The resin film 1 is not particularly limited as long as it can ensure insulation, and various plastic films can be used. Materials for the resin film include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyimide resins such as polyimide (PI), polyethylene (PE), polypropylene (PP ) and other polyolefin-based resins, acetate-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyamide-based resins, cycloolefin-based resins, (meth)acrylic-based resins, polyvinyl chloride-based resins, polyvinylidene chloride-based resins, polystyrene system resins, polyvinyl alcohol-based resins, polyarylate-based resins, polyphenylene sulfide-based resins, and the like. Among these, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) and polyimide resins such as polyimide (PI) are used from the viewpoint of heat resistance, durability, flexibility, production efficiency, cost, etc. preferable. In particular, from the viewpoint of cost performance, polyethylene terephthalate (PET) is preferable.

The surface of the resin film is preliminarily subjected to sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, and other etching treatments and undercoating treatments to ensure adhesion with the conductive layer formed on the resin film. You may make it guarantee. In addition, before forming the conductive layer, the surface of the resin film may be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, or the like, if necessary.

The thickness of the resin film is preferably in the range of 2 to 300 μm, more preferably in the range of 10 to 250 μm, even more preferably in the range of 20 to 200 μm. In general, a thicker resin film is preferable because it is less susceptible to thermal shrinkage and the like during heating. However, it is desirable to reduce the thickness of the resin film to some extent due to the compactness of electronic parts and the like. On the other hand, if the thickness of the resin film is too thin, the moisture permeability and permeability of the resin film increase, allowing moisture, gas, etc. to permeate, and the conductive layer is likely to be oxidized. Therefore, in the present embodiment, by reducing the thickness of the resin film while maintaining a certain thickness, the conductive film itself can be made thin, and the thickness can be suppressed when used for an electromagnetic wave shield sheet, a sensor, or the like. becomes. As a result, it is possible to reduce the thickness of electromagnetic wave shield sheets, sensors, and the like. Furthermore, when the thickness of the resin film is within the above range, the mechanical strength is sufficient while ensuring the flexibility of the resin film, and the operation of continuously forming the base layer and the conductive layer by rolling the film is possible.

(First conductive layer)
The first conductive layer 21 provided on one side of the resin film 1 preferably has an electrical resistivity of 100 μΩcm or less in order to sufficiently obtain an electromagnetic wave shielding effect, a sensor function, and the like. The constituent material of the first conductive layer 21 is not particularly limited as long as it satisfies such electrical resistivity and has conductivity. , Zn, Sn, Au, Ag, Co, Cr, Ni, Pb, Pd, Pt, W, Zr, Ta, Hf, Mo, Mn, Mg, V and the like are preferably used. In addition, those containing two or more of these metals, or alloys or oxides containing these metals as main components can also be used. Among these conductive compounds, Cu and Al are preferably contained from the viewpoints of high conductivity contributing to electromagnetic wave shielding properties and sensor function and relatively low cost. In particular, from the viewpoint of cost performance and production efficiency, it is preferable to contain Cu, but elements other than Cu may be contained to the extent of impurities. As a result, the electrical resistivity is sufficiently low and the electrical conductivity is high, so that the electromagnetic wave shielding characteristics and the sensor function can be improved.

The thickness of the first conductive layer 21 is preferably 10 nm or more and 300 nm or less. The lower limit of the thickness of the first conductive layer 21 is more preferably 20 nm, still more preferably 80 nm. On the other hand, the upper limit of the thickness of the first conductive layer 21 is more preferably 260 nm, still more preferably 240 nm. If the thickness of the first conductive layer 21 exceeds the above upper limit, the conductive film tends to curl after heating, or it becomes difficult to make the device thinner. If the thickness is less than the above lower limit, the surface resistance of the conductive film tends to increase under humidified heat conditions, and the target humidified heat reliability cannot be obtained, or the strength of the conductive layer is reduced, resulting in poor pattern wiring. Delamination may occur.

A method for forming the first conductive layer 21 is not particularly limited, and a conventionally known method can be adopted. 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 The film is preferably formed by coating method, plating method (electrolytic plating, electroless plating), hot stamping method, coating method, or the like. Moreover, a plurality of these film forming methods may be combined, and an appropriate method may be adopted according to the required film thickness. Among them, the sputtering method and the vacuum film forming method are preferable, and the sputtering method is particularly preferable. This enables continuous production by a roll-to-roll manufacturing method, thereby increasing production efficiency and controlling the film thickness during film formation, thereby suppressing an increase in the surface resistance value of the conductive film. In addition, a thin, uniform film thickness and dense conductive layer can be formed. When vacuum film formation (especially sputtering film formation) is performed while continuously unwinding a film using a roll-to-roll manufacturing method, the method for forming the second conductive layer described later can be suitably adopted. .

(protective layer)
The protective layer can be formed on the outermost surface of the first conductive layer 21 (not shown) in order to prevent the first conductive layer 21 from being naturally oxidized under the influence of atmospheric oxygen. ). The protective layer can typically be formed by mounting a target for forming the protective layer downstream of the metal material source (target) for forming the first conductive layer 21 and performing sputtering film formation.

The protective layer is not particularly limited as long as it exhibits a rust-preventive effect on the first conductive layer 21, but is preferably a metal that can be sputtered, such as Ni, Cu, Ti, Si, Zn, Sn, Cr, Fe, indium, gallium, One or more metals selected from antimony, zirconium, magnesium, aluminum, gold, silver, palladium, and tungsten, or oxides thereof are used. Ni, Cu, and Ti form a passivation layer and thus are not easily corroded, Si improves corrosion resistance and thus is not easily corroded, and Zn and Cr are metals which are not easily corroded because they form a dense oxide film on the surface. preferable.

As the material of the protective layer, an alloy composed of two kinds of metals can be used from the viewpoint of securing adhesion to the first conductive layer 21 and reliably preventing the first conductive layer 21 from rusting. Alloys of more than one metal are preferred. Examples of alloys composed of three or more metals include Ni--Cu--Ti, Ni--Cu--Fe, and Ni--Cu--Cr. Ni--Cu--Ti is preferred from the viewpoint of rust prevention and production efficiency. preferable. From the viewpoint of securing adhesion with the first conductive layer 21, an alloy containing the material for forming the first conductive layer 21 is preferable. Thereby, oxidation of the first conductive layer 21 can be reliably prevented.

Examples of materials for the protective layer include indium-doped tin oxide (ITO), antimony-containing tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), and indium-doped zinc oxide ( IZO) may be included. It is preferable because it not only suppresses an increase in the initial surface resistance value of the conductive film, but also suppresses an increase in the surface resistance value under humidified heat conditions, thereby optimizing the stabilization of the surface resistance value.

The metal oxides are preferably oxides such as SiOx (x=1.0 to 2.0), copper oxide, silver oxide, and titanium oxide. It is also possible to provide an antirust effect by forming a resin layer such as an acrylic resin or an epoxy resin on the first conductive layer 21 instead of the above-described metal, alloy, oxide, or the like.

The film thickness of the protective layer is preferably 1 to 50 nm, more preferably 2 to 30 nm, and more preferably 3 to 20 nm. As a result, the durability is improved and the surface layer can be prevented from being oxidized, so that the increase in the surface resistance value under humidified heat conditions can be suppressed.

《Process B》
In step B, the first protective film 31 is attached onto the first conductive layer 21 . It is preferable to bond the first protective film 31 immediately after the film formation of the first conductive layer 21 (in the same line as the film formation line of the first conductive layer). Oxidation, scratches, etc. of the first conductive layer 21 can thereby be reduced.

(Protective film)
The surface of the first protective film 31 that is in contact with the first conductive layer 21 has adhesiveness. Although the material and structure of the first protective film 31 are not particularly limited, it preferably has a base layer containing a polyolefin resin and an adhesive layer containing a thermoplastic elastomer. As a material for forming the adhesive layer, a known adhesive such as a removable acrylic adhesive can also be used.

The polyolefin-based resin that forms the base layer is not particularly limited. Ethylene-based polymer: Examples include olefin-based polymers such as ethylene-α-olefin copolymers, and olefin-based polymers of ethylene components and other monomers such as ethylene-vinyl acetate copolymers and ethylene-methyl methacrylate copolymers. These polyolefin resins may be used singly or in combination of two or more.

The base material layer 1 contains an olefin resin as a main component. Additives such as fillers such as calcium oxide, magnesium oxide, silica, zinc oxide and titanium oxide, pigments, anti-staining agents, lubricants and anti-blocking agents can be appropriately blended.

The thickness of the base material layer 1 is not particularly limited, but is preferably 20 μm or more and 200 μm or less, more preferably 30 μm or more and 150 μm or less, and even more preferably 40 μm or more and 100 μm or less. Further, the substrate layer 1 may be a single layer or may be composed of multiple layers of two or more layers.

The surface of the substrate layer 1 opposite to the surface on which the adhesive layer is provided is subjected to surface treatment such as corona discharge treatment, flame treatment, plasma treatment, sputter etching treatment, undercoat treatment such as a primer, etc., if necessary. can also

As the thermoplastic elastomer forming the adhesive layer 2, those used as base polymers for adhesives, such as styrene-based elastomers, urethane-based elastomers, ester-based elastomers, and olefin-based elastomers, can be used without particular limitation. More specifically, styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-ethylene-butylene copolymer-styrene (SEBS), styrene-ethylene-propylene copolymer-styrene (SEPS ), etc.; styrene/butadiene (SB), styrene/isoprene (SI), styrene/ethylene-butylene copolymer (SEB), styrene/ethylene-propylene copolymer (SEP), etc. A-B type block polymer; styrene-based random copolymer such as styrene/butadiene rubber (SBR); A-B-C type styrene/olefin such as styrene/ethylene-butylene copolymer/olefin crystal (SEBC) Crystalline block polymer; CBC type olefin crystalline block polymer such as olefin crystal, ethylene-butylene copolymer, olefin crystal (CEBC); ethylene-αolefin, ethylene-propylene-αolefin, propylene-α Olefinic elastomers such as olefins, hydrogenated products thereof, and the like are mentioned. These thermoplastic elastomers may be used singly or in combination of two or more.

For the formation of the adhesive layer 2, the thermoplastic elastomer may be added with, for example, a softening agent, an olefin resin, a silicone polymer, a liquid acrylic copolymer, phosphoric acid, or the like, if necessary, for the purpose of controlling adhesive properties. Ester compounds, tackifiers, antioxidants, hindered amine light stabilizers, UV absorbers, and other additives such as fillers and pigments such as calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide. can be appropriately blended.

The thickness of the adhesive layer 2 is not particularly limited, and may be determined appropriately according to the required adhesive strength, etc., but it is usually about 0.1 to 50 μm, preferably 0.2 to 40 μm, and more preferably about 0.2 to 40 μm. It is preferably 0.3 to 20 μm.

The surface of the adhesive layer 2 requires surface treatment such as corona discharge treatment, ultraviolet irradiation treatment, flame treatment, plasma treatment, sputter etching treatment, etc., for the purpose of controlling adhesiveness and attaching workability. It can also be applied accordingly. Furthermore, the adhesive layer 2 can be temporarily attached with a separator or the like to protect it until it is put to practical use, if necessary.

In addition, a release layer for imparting releasability can be formed on the surface of the substrate layer opposite to the surface on which the adhesive layer is attached, if necessary. The release layer may be formed by co-extrusion together with the substrate layer and the adhesive layer, or may be formed by coating.

When the release layer is formed by co-extrusion, it is preferable to use a mixture of two or more polyolefin resins. By using a mixture of two or more polyolefin resins, the compatibility of the two polyolefin resins is controlled to form an appropriate surface roughness and to impart appropriate releasability. be. When the release layer is formed by co-extrusion, its thickness is usually about 1 to 50 μm, preferably 2 to 40 μm, more preferably 3 to 20 μm.

As the release agent for forming the release layer by coating, any release agent capable of imparting release properties can be used without particular limitation. For example, release agents include silicone-based polymers and long-chain alkyl-based polymers. The release agent may be a non-solvent type, a solvent type dissolved in an organic solvent, or an emulsified type emulsified in water. It can be attached to the base material layer 1 . In addition, as the mold release agent, an ultraviolet curing type and the like can be mentioned. Specific examples of release agents that can be obtained include Pyroyl (manufactured by Ipposha Yushi Co., Ltd.) and Shin-Etsu Silicone (manufactured by Shin-Etsu Chemical Co., Ltd.).

The thickness of the release layer 3 is not particularly limited. It is preferable to have

《Process C》
In step C, a second conductive layer having a thickness of 80 nm or more and 300 nm or less is formed on the other surface of the resin film 1 by sputtering while the resin film 1 is drawn out. As a result, the protective film 31 functions as a reinforcing material for the resin film 1 during the formation of the second conductive layer 22 , thereby suppressing wrinkles in the resin film 1 . Depending on the thickness of the second conductive layer, step C, which is a sputtering step, is not limited to one time, and may be performed two or more times. The properties of the second conductive layer and the deposition procedure by the sputtering method will be described below.

As for the constituent material and electrical resistivity of the second conductive layer 22, those similar to those of the first conductive layer 21 can be preferably adopted.

The thickness of the second conductive layer 22 is 80 nm or more and 300 nm or less from the viewpoint of low resistance and thinning. The lower limit of the thickness of the second conductive layer 22 is preferably 90 nm, more preferably 100 nm. On the other hand, the upper limit of the thickness of the second conductive layer 22 is preferably 280 nm, more preferably 250 nm. The thicknesses of the conductive layers on both sides may be the same or different.

The absolute value of the difference between the thickness of the first conductive layer 21 and the thickness of the second conductive layer 22 is preferably 5 nm or less, more preferably 3 nm or less. By making the thicknesses of the conductive layers on both sides close to each other, the stress generated in the conductive layers is canceled, and curling of the conductive film, peeling of the conductive layers, and the like can be prevented.

(Configuration of film forming apparatus)
The second conductive layer 22 is preferably formed by a roll-to-roll method while the resin film 1 is being fed out. Film formation of the second conductive layer by the roll-to-roll method is performed using a winding-type vacuum film formation apparatus 300 as schematically shown in FIG. A vacuum film-forming apparatus 300 includes a delivery roll 301 and a take-up roll 302 , and a film-forming roll 310 and transport rolls 303 and 304 on a film transport path between the delivery roll 301 and the take-up roll 302 . Note that the number of transport rolls is not particularly limited. Each transport roll may be of a free-rotating type or a driven-rotating type. From the viewpoint of controlling the tensile stress in the MD direction at the film-forming location, at least one of the transport rolls between the film-forming roll 310 and the take-up roll 302 is preferably a driven rotating roll. Further, a driven rotating roll may be arranged between the delivery roll 301 and the film forming roll 310 . In addition, the tensile stress in the MD direction at the film-forming location refers to the tension between the film-forming roll and the driving roll closest to the film-forming roll on the transport path of the film. The driving roll may be a single driven rotating roll, or may be a pair of nip rolls that hold the film between two rolls.

Furthermore, from the viewpoint of controlling the tensile stress at the film-forming location, it is preferable that the vacuum film-forming apparatus is equipped with tensile stress detecting means such as a tension pick-up roll and a dancer roll in the transport path. Moreover, from the viewpoint of stabilizing the transportation of the film, it is preferable to have a structure that has a tensile stress control mechanism and can control the tensile stress at the film-forming location to be constant. When the tensile stress detected by the tensile stress detecting means such as the tension pick-up roll is higher than the set value, the tensile stress control mechanism controls the driving rotation roll located downstream of the tensile stress detecting means in the conveying path. When the peripheral speed is decreased and the tensile stress is lower than the set value, the mechanism performs feedback so that the peripheral speed of the driven rotating roll is increased.

From the standpoint of independently controlling the tensile stress at the film forming location and the film winding stress on the winding roll 302, a tension cutting means is provided in the film transport path between the film forming roll 310 and the winding roll 302. is preferred. In addition, from the viewpoint of independently controlling the tensile stress at the film formation location and the stress delivered from the delivery roll 301, a tension cutting means may be provided in the film transport path between the delivery roll 301 and the film formation roll 310. preferable.

As the tension cutting means, in addition to the nip roll, a suction roll, or a group of rolls arranged so that the film transport path is S-shaped can be used. Further, an appropriate tensile stress detecting means such as a tension pick-up roll is arranged in the conveying path between the tension cutting means and the winding roll 302, and winding is performed so that the winding stress is constant by an appropriate tensile stress control mechanism. Preferably, the rotational torque of roll 302 is adjusted. In this way, by independently controlling the tensile stress, the winding stress, and/or the unwinding stress at the film-forming location, it is possible to obtain a poor winding state due to a small winding stress, or a poor film quality due to a large winding stress. It is possible to suppress the occurrence of problems such as blocking.

It is preferable that the film forming roll 310 is configured to be temperature controllable. As means for controlling the temperature of the roll, there are a configuration in which a hot medium (and a refrigerant) can be circulated inside the roll, a configuration in which a heating means such as an electric heater is provided in the roll, and a heating means such as an infrared heater that heats the roll from the outside of the roll. Examples include a configuration in which the surface can be heated. A target 320 is mounted in the vicinity of the film forming roll, and film formation is performed by depositing metal atoms vaporized from this target 320 on the substrate. The number of targets 320 is not particularly limited, and can be appropriately set in consideration of the film quality and productivity of the conductive layer, and may be one as shown in FIG. When using a plurality of targets, they may be installed in order from upstream to downstream of the line.

(Deposition conditions)
A laminate L of the resin film 1, the first conductive layer 21, and the protective film 31 is fed from a feeding roll 301, and is continuously fed through a plurality of transport rolls 303 and 304 and a film forming roll 310 so as not to loosen. be transported. The conductive film 100 on which the second conductive layer 22 has been vacuum-formed on the film-forming roll 310 is taken up by the take-up roll 302 .

The tensile stress in the MD direction of the resin film 1 at the film formation location is preferably 1 MPa or more, more preferably 1 MPa or more and 3 MPa or less, and further preferably 1.5 MPa or more and 2.5 MPa or less. By setting the tensile stress within the above range, the occurrence of wrinkles can be suppressed. If the tensile stress is too small, wrinkles are likely to occur, and if it is too large, the resin film 1 itself may be deformed.

The temperature of the film forming roll 310 when forming the second conductive layer 22 is preferably 40°C to 150°C, more preferably 50°C to 140°C, and further preferably 60°C to 130°C. preferable. If the temperature of the film-forming roll is excessively low, the temperature difference between the side of the resin film 1 contacting the film-forming roll and the side of the film-forming roll increases, that is, the temperature distribution in the film thickness direction increases. It is presumed that wrinkles are likely to occur in the resin film 1 . On the other hand, if the temperature of the film-forming roll is excessively high, the thermal deformation of the film on the film-forming roll becomes large, so it is presumed that wrinkles tend to occur.

Other film formation conditions are not particularly limited. For example, when the first conductive layer 21 made of copper is formed by a sputtering method, copper (preferably oxygen-free copper) is used as a target, and a sputtering apparatus is used first. The degree of vacuum (ultimate degree of vacuum) inside is preferably reduced to 1×10 ⁻³ Pa or less to create an atmosphere from which impurities such as moisture in the sputtering apparatus and organic gases generated from the resin film are removed. preferable.

An inert gas such as Ar is introduced into the sputtering apparatus evacuated in this way, and the film-forming roll temperature is adjusted to the temperature in the range while conveying the resin film under the tensile stress applied in the range. Sputter deposition is performed under reduced pressure. The pressure during film formation is preferably 0.05 Pa to 1.0 Pa, more preferably 0.1 Pa to 0.7 Pa. If the film-forming pressure is too high, the film-forming speed tends to decrease. Conversely, if the pressure is too low, the discharge tends to become unstable.

The transport speed of the film and the power density per target can be set in consideration of the film quality and film thickness of the conductive layer, production efficiency and the like. The transport speed of the film is preferably 2 m/min or more and 20 m/min or less, more preferably 3 m/min or more and 18 m/min or less. The power density per target is preferably 20 kW/m ² or more and 100 kW/m ^{2 or} less, more preferably 25 kW/m ² or more and 90 kW/m ² or less.

In step C, the total power density represented by the following formula in the sputtering method is preferably 1500 kW/m ² or less, more preferably 1200 kW/m ² or less.
Total power density = N x T x P
(In the formula, N is the number of process repetitions, T is the number of targets per process, and P is the power density [kW/m ² ] per target.)

By setting the total power density at the time of sputtering in step C to a predetermined value or less, the load on the resin film is reduced, and the occurrence of wrinkles can be suppressed at a higher level. Also, in order to form a thick conductive layer, it is possible to employ a procedure in which sputtering is performed a few times at high power density, or a procedure in which sputtering is performed many times at low power density. In any procedure, by controlling the total power density obtained by the above formula within a predetermined range, it is possible to produce a conductive film with good production efficiency while suppressing wrinkles in the resin film. Considering productivity, it is preferably 80 kW/m ² or more, more preferably 100 kW/m ² or more.

《Process D》
In this embodiment, following the step C, a step D of bonding the second protective film 32 onto the second conductive layer 22 may be further included. As the second protective film 32, a film having the same configuration as the first protective film 31 can be preferably adopted. As in the bonding of the first protective film 31, from the viewpoint of reducing oxidation, damage, etc. of the second conductive layer 22, immediately after the film formation of the second conductive layer 22 (the same line as the film formation line of the second conductive layer) It is preferable to bond the second protective film 32 together within the production line). Through this step D, it is possible to manufacture a conductive film with a protective film in which a conductive layer and a protective film are laminated in order on both sides of a resin film.

When the conductive film is incorporated into various devices, it is usually used after peeling off the protective film on one side or both sides depending on the application.

(Conductive film)
The initial surface resistance value R1 of the conductive film 100 is preferably 0.001 Ω/square to 10.0 Ω/square, more preferably 0.01 Ω/square to 7.5 Ω/square, and 0.01 Ω/square to 7.5 Ω/square. It is more preferably 1 Ω/□ to 5.0 Ω/□. This makes it possible to provide a practical conductive film with excellent production efficiency.

The thickness of the entire conductive film 100 is preferably in the range of 2 to 300 μm, more preferably in the range of 10 to 250 μm, even more preferably in the range of 20 to 200 μm. As a result, the resistance of the conductive film can be reduced while the thickness of the conductive film itself can be reduced. As a result, it is possible to reduce the thickness of electromagnetic wave shield sheets, sensors, and the like. Furthermore, when the thickness of the conductive film is within the above range, it is possible to ensure sufficient mechanical strength while ensuring flexibility, and the film is rolled and the Si-containing layer, the conductive layer, etc. are continuously formed. Forming operation becomes easy, and production efficiency improves.

The conductive film may be wound into a roll from the viewpoint of transportability and handling. By continuously forming the base layer and the conductive layer on the resin film by the roll-to-roll method, the conductive film can be produced efficiently.

(Application of conductive film)
The conductive film can be applied to various uses, for example, it can be applied to an electromagnetic wave shield sheet, a planar sensor, and the like. The electromagnetic wave shield 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 shield sheet is preferably 20 to 200 μm. In addition, when the protective film is stuck together, it can be used after peeling a protective film.

The shape of the electromagnetic wave shield sheet is not particularly limited, and depending on the shape of the object to be installed, the shape when viewed from the stacking direction (the same direction as the thickness direction of the sheet) is square, circular, triangular, or polygonal. Any suitable shape can be selected.

A planar sensor uses a conductive film, and includes sensors that sense various physical quantities in addition to user interface applications such as touch panels and controllers of mobile devices. The thickness of the planar sensor is preferably 20 to 200 μm.

<<Second embodiment>>
(Underlayer)
In this embodiment, the conductive film 100 has a base layer (not shown) between the resin film 1 and the first conductive layer 21 or between the resin film 1 and the second conductive layer 22. may be provided. The performance of the conductive film can be improved by providing the base layer according to the purpose, such as adhesion of the conductive layer to the resin film, imparting strength to the conductive film, and control of electrical properties. The base layer is not particularly limited, and includes an easy-adhesion layer, a hard coat layer (including those functioning as an anti-blocking layer, etc.), a dielectric layer, and the like.

(Easy adhesion layer)
The easy-adhesion layer is a cured film of an adhesive resin composition. The easy-adhesion layer has good adhesion to the conductive layer.

As the adhesive resin composition, those having sufficient adhesiveness and strength as a cured film after forming the easy adhesion layer can be used without particular limitation. Examples of resins to be used include thermosetting resins, thermoplastic resins, ultraviolet curing resins, electron beam curing resins, two-liquid mixed resins, and mixtures thereof. Therefore, an ultraviolet curable resin is preferable because it can efficiently form an easy-adhesion layer with a simple processing operation. By containing an ultraviolet curable resin, an adhesive resin composition having ultraviolet curable properties can be easily obtained.

As the adhesive resin composition, a material that forms a crosslinked structure upon curing is preferable. When the cross-linking structure in the easy-adhesion layer is promoted, the film internal structure, which was loose until then, becomes strong, and the film strength is improved. This is because it is presumed that such an improvement in film strength contributes to an improvement in adhesion.

The adhesive resin composition preferably contains at least one of (meth)acrylate monomers and (meth)acrylate oligomers. This facilitates the formation of a crosslinked structure resulting from the C═C double bond contained in the acryloyl group, thereby efficiently improving the film strength. In addition, in this specification, (meth)acrylate means an acrylate or a methacrylate.

The (meth)acrylate monomer and/or acrylate oligomer having a (meth)acryloyl group as a main component used in the present embodiment has a function 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, dipentaerythritol 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)acrylate, and mixtures of two or more thereof.

Among the (meth)acrylates, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, or mixtures thereof are preferred from the viewpoint of abrasion resistance and curability. Especially preferred.

A urethane acrylate oligomer can also be used. A urethane (meth)acrylate oligomer can be produced by reacting a polyol with a polyisocyanate and then reacting a (meth)acrylate having a hydroxyl group, or by reacting a polyisocyanate with a (meth)acrylate having a hydroxyl group. , a method of reacting a polyol, and a method of reacting a (meth)acrylate having a polyisocyanate, a polyol, and a hydroxyl group, but are not particularly limited.

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

If the crosslink density is too high, the performance as a primer deteriorates and the adhesion to the conductive layer tends to decrease, so a low-functional (meth)acrylate having a hydroxyl group (hereinafter referred to as hydroxyl-containing (meth)acrylate) may be used. Examples of hydroxyl group-containing (meth)acrylates 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.

The UV-curable adhesive resin composition of the present embodiment has improved antiblocking properties by blending a (meth)acrylic group-containing silane coupling agent. (Meth)acryl group-containing silane coupling agents include 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, etc., and commercially available products include KR-513 and KBM-5103 (manufactured by Shin-Etsu Chemical Co., Ltd., trade names).

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

The easy-adhesion layer of the present embodiment may contain nanosilica fine particles. As the nanosilica fine particles, organosilica sol synthesized from alkylsilane or nanosilica synthesized by plasma arc can be used. Examples of commercially available products include PL-7-PGME (manufactured by Fuso Chemical, trade name) for the former, and SIRMIBK15WT%-M36 (manufactured by CIK Nanotech, trade name) for the latter. The blending ratio of the nanosilica fine particles is preferably 5 to 30 parts by weight, preferably 5 to 10 parts by weight, with respect to 100 parts by weight of the total weight of the (meth)acryloyl group-containing (meth)acrylate monomer and/or acrylate oligomer and the silane coupling agent. Parts by weight are more preferred. When the content is at least the lower limit, surface irregularities are formed, anti-blocking properties can be imparted, and roll-to-roll production becomes possible. A decrease in adhesion to the conductive layer can be prevented by setting the content to be equal to or less than the upper limit.

The average particle diameter of the nanosilica fine particles is preferably 100-500 nm. If the average particle size is less than 100 nm, the amount of addition required to form irregularities on the surface is too large to obtain adhesion to the conductive layer. a problem arises.

The adhesive resin composition preferably contains a photopolymerization initiator in order to impart ultraviolet curability. Examples of 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-hydroxycyclohexylphenyl 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-Hydroxyalkylphenones such as on, 2-methyl-1-[4-(methylthio)phenyl]-1-morpholinopropane, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)- α-aminoalkylphenones such as 1-butanone, monoacylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis(2,6- monoacylphosphine oxides such as dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;

Alkylphenone-based photopolymerization initiators are preferred in terms of resin curability, light stability, compatibility with resins, low volatility, and low odor. -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 preferred, commercially available as Irgacure 127, 184, 369, 651, 500, 891, 907 , 2959, Darocure 1173, TPO (manufactured by BASF Japan Ltd., trade name), etc. The photopolymerization initiator has a (meth) acryloyl group (meth) acrylate monomer and / or acrylate oligomer 100 parts by weight, A solid content of 3 to 10 parts by weight is blended.

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

The easy adhesion layer is formed by applying the above varnish on the cycloolefin resin film 1 . The method of applying the varnish can be appropriately selected depending on the varnish and the conditions of the coating process. It can be applied by a method, an extrusion coating method, or the like.

After applying the varnish, the coating film is cured to form an easy-adhesion layer. When the varnish contains a solvent, the curing treatment of the UV-curable adhesive resin composition may be performed by drying the varnish (for example, at 80° C. for 1 minute) to remove the solvent, and then using an ultraviolet irradiation machine at 500 mW/cm ² to 3000 mW/cm. There is a procedure of curing by UV treatment with an irradiation intensity of cm ² and a work load of 50 to 400 mJ/cm ² . Ultraviolet lamps are generally used as ultraviolet light sources, and specific examples include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, and metal halide lamps. Alternatively, an inert gas such as nitrogen or argon may be used.

Heating is preferably performed during the ultraviolet curing treatment. A curing reaction of the adhesive resin composition proceeds by irradiation with ultraviolet rays, and a crosslinked structure is formed at the same time. By heating at this time, the formation of the crosslinked structure can be sufficiently promoted even with a low ultraviolet dose. The heating temperature can be set according to the degree of cross-linking, and is preferably 50°C to 80°C. The heating means is not particularly limited, and a hot air dryer, a radiant heat dryer, heating of film transport rolls, or the like can be appropriately employed.

Although the thickness of the adhesion layer is not particularly limited, it is preferably 0.2 μm to 2 μm, more preferably 0.5 μm to 1.5 μm, even more preferably 0.8 μm to 1.2 μm. . By setting the thickness of the easy adhesion layer within the above range, the adhesion of the conductive layer and the flexibility of the film can be improved.

(Hard coat layer)
A hard coat layer may be provided as the base layer. Furthermore, particles may be added to the hard coat layer in order to prevent blocking between the conductive films and enable production by the roll-to-roll method.

For forming the hard coat layer, the same adhesive composition as that for the easy adhesion layer can be suitably used. In order to impart antiblocking properties, it is preferable to incorporate particles into the adhesive composition. As a result, unevenness can be formed on the surface of the hard coat layer, and anti-blocking properties can be suitably imparted to the conductive film 100 .

As the above particles, those having transparency such as various metal oxides, glasses, plastics, etc. can be used without particular limitation. For example, inorganic particles such as silica, alumina, titania, zirconia, calcium oxide, etc., polymethyl methacrylate, polystyrene, polyurethane, acrylic resin, acrylic-styrene copolymer, benzoguanamine, melamine, polycarbonate, etc. Examples include crosslinked organic particles and silicone particles. One 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 while considering the degree of surface unevenness. The average particle diameter is preferably 0.5 μm to 2.0 μm, and the amount to be added is preferably 0.2 to 5.0 parts by weight per 100 parts by weight of the resin solid content of the composition.

(dielectric layer)
One or more dielectric layers may be provided as the underlying layer. The dielectric layer is made of an inorganic material, an organic material, or a mixture of an inorganic material and an organic material. Materials for forming the dielectric _layer include NaF, _Na3AlF6 , LiF, _MgF2 , _CaF2 , SiO2, _LaF3 , _CeF3 , _{Al2O3 , TiO2 , Ta2O5} , _{ZrO2 ,} Inorganic substances such as ZnO, ZnS, and SiO _x (where x is 1.5 or more and less than 2) and organic substances such as acrylic resins, urethane resins, melamine resins, alkyd resins, and siloxane-based polymers can be used. In particular, it is preferable to use a thermosetting resin composed of a mixture of melamine resin, alkyd resin and organic silane condensate as the organic material. The dielectric layer can be formed using the above materials by a coating method such as a gravure coating method or a bar coating method, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

The thickness of the dielectric layer is preferably 10 nm to 250 nm, more preferably 20 nm to 200 nm, even more preferably 20 nm to 170 nm. If the thickness of the dielectric layer is too small, it is difficult to form a continuous film. Also, if the dielectric layer is too thick, cracks tend to occur in the dielectric layer.

The dielectric layer may have nanoparticles with an average particle size of 1 nm to 500 nm. The content of nanoparticles in the dielectric layer is preferably 0.1 wt % to 90 wt %. The average particle diameter of the nanoparticles used in the dielectric layer is preferably in the range of 1 nm to 500 nm, more preferably 5 nm to 300 nm, as described above. Also, the content of the nanoparticles in the dielectric layer is more preferably 10 wt % to 80 wt %, and even more preferably 20 wt % to 70 wt %.

Examples of inorganic oxides forming nanoparticles include fine particles such as silicon oxide (silica), hollow nanosilica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide. Among these, fine particles of silicon oxide (silica), titanium oxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide are preferred. These may be used individually by 1 type, and may use 2 or more types together.

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

<Examples 1 and 2: Preparation of double-sided conductive film with single-sided protective film>
First, a long resin film made of a polyethylene terephthalate film (manufactured by Toray Advanced Film Co., Ltd., product name “150-TT00A”, hereinafter referred to as PET film) having a width of 1.100 m, a length of 2500 m, and a thickness shown in Table 1. was wound around a delivery roll and placed in a sputtering apparatus as shown in FIG. After that, the inside of the sputtering device was evacuated to a high vacuum of 3.0×10 ⁻³ Torr, and in this state, sputtering film formation was performed while sending the long resin film from the delivery roll to the take-up roll. In an atmosphere of 3.0×10 ⁻³ Torr consisting of 100% by volume of Ar gas, using Cu as a metal target material, a first conductive layer was sputter-formed on one side by a sintered body DC magnetron sputtering method. By winding the film around a delivery roll, a wound body of a single-sided conductive film having a conductive layer formed on one side was produced. The values shown in Table 1 were used for the line transfer speed during sputtering film formation, the number of repetitions N of sputtering film formation, the number of targets per line T, and the power density P [kW/m ² ] per target. Also, the total power density during the sputtering film formation was calculated based on the following formula.
Total power density = N x T x P
(N is the number of repetitions of sputtering deposition, T is the number of targets per line, and P is the power density [kW/m ² ] per target.)

The adhesive layer side of a protective film (manufactured by Futamura Chemical Co., Ltd., "FSA020M") having a thickness shown in Table 1 is attached to the first conductive layer side of the wound body of the produced single-sided conductive film, and one side is protected. A wound body of a single-sided conductive film with a single-sided protective film was produced by laminating films.

A conductive layer is formed on both sides by sputtering a second conductive layer under the same conditions as the first conductive layer on the side opposite to the surface on which the protective film is arranged of the single-sided conductive film with the manufactured single-sided protective film. A double-sided conductive film with a single-sided protective film was prepared by forming a protective film on one side. Both the first conductive layer and the second conductive layer were formed with the thickness shown in Table 1. The tension applied in the MD direction of the resin film in Example 1 was 290 N, and the tensile stress calculated from the film width and thickness was 1.76 MPa.

<Comparative Examples 1 to 4: Production of double-sided conductive film (without protective film)>
A roll of a single-sided conductive film was produced in the same manner as in Example 1. Next, a double-sided conductive film having conductive layers formed on both sides by sputtering a second conductive layer on the opposite side of the roll of the single-sided conductive film from the first conductive layer under the same conditions as the first conductive layer. was made. Both the first conductive layer and the second conductive layer were formed with the thickness shown in Table 1. In addition, the values shown in Table 1 were used for the line transport speed during sputtering film formation, the number of repetitions N of sputtering film formation, the number of targets per line T, and the power density P [kW/m ² ] per target.

<Reference Example 1: Production of double-sided conductive film (without protective film)>
A roll of a single-sided conductive film was produced in the same manner as in Example 1. Next, a double-sided conductive film having conductive layers formed on both sides by sputtering a second conductive layer on the opposite side of the roll of the single-sided conductive film from the first conductive layer under the same conditions as the first conductive layer. was made. Both the first conductive layer and the second conductive layer were formed with the thickness shown in Table 1. In addition, the values shown in Table 1 were used for the line transport speed during sputtering film formation, the number of repetitions N of sputtering film formation, the number of targets per line T, and the power density P [kW/m ² ] per target.

<Evaluation>
The following evaluations were performed on the produced conductive films. Each result is shown in Table 1.

(1) Measurement of Thickness The thickness of the conductive layer was measured by observing the cross section of the conductive film with the protective film using a transmission electron microscope (manufactured by Hitachi, Ltd., product name “H-7650”).

(2) Evaluation of wrinkles The produced conductive film with a protective film was evaluated for the occurrence of wrinkles. A length of about 10 m was pulled out from the wound body of the conductive film, the conductive film was irradiated with a fluorescent lamp, and the presence or absence of wrinkles in the second conductive layer was visually observed. The case where wrinkles were not observed was evaluated as "◯", and the case where wrinkles were observed was evaluated as "x".

(result)
From Table 1, it can be seen that the occurrence of wrinkles was suppressed in the examples in which the second conductive layer was formed while the protective film was attached to the first conductive layer. On the other hand, it can be seen that wrinkles occurred in Comparative Examples 1 to 4 in which the second conductive layer was formed without a protective film. In Reference Example 1 in which a thin conductive layer was formed, no wrinkles occurred. From this, it can be seen that the occurrence of wrinkles is a phenomenon that is characteristically seen when forming a thick conductive layer.

1 Resin Film 21 First Conductive Layer 22 Second Conductive Layer 31 First Protective Film 32 Second Protective Film 100 Conductive Film 300 Film Forming Apparatus 301 Delivery Roll 302 Winding Roll 303, 304 Transport Roll 310 Film Forming Roll 320 Target

Claims (6)

Step A of forming a first conductive layer on one surface of the resin film;
A step B of bonding a protective film onto the first conductive layer, and a step C of forming a second conductive layer having a thickness of 80 nm or more and 300 nm or less on the other surface of the resin film by a sputtering method while extending the resin film.
including
The constituent material of the first conductive layer is Cu, Al, Fe, Cr, Ti, Si, Nb, In, Zn, Sn, Au, Ag, Co, Cr, Ni, Pb, Pd, Pt, W, Zr, A method for producing a conductive film comprising at least one metal selected from Ta, Hf, Mo, Mn, Mg and V, or an alloy containing said metal as a main component. 2. The method for producing a conductive film according to claim 1, wherein in said step A, said first conductive layer is formed by a sputtering method. 3. The method for producing a conductive film according to claim 1, wherein the first conductive layer has a thickness of 80 nm or more and 300 nm or less. The method for producing a conductive film according to any one of claims 1 to 3, wherein the protective film has a thickness of 20 µm or more and 200 µm or less. The method for producing a conductive film according to any one of claims 1 to 4, wherein in the step C, the total power density represented by the following formula in the sputtering method is 1500 kW/m ² or less.
Total power density = N x T x P
(In the formula, N is the number of process repetitions, T is the number of targets per process, and P is the power density [kW/m ² ] per target.) 6. The method for producing a conductive film according to any one of claims 1 to 5, wherein in the step C, the resin film has a tensile stress of 1 MPa or more in the MD direction.

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