KR20200074860A - Conductive film - Google Patents

Abstract

The present invention provides a conductive film which can suppress an occurrence of disconnection in patterning a metal layer even though a relatively thin metal layer is formed. The conductive film has a first metal layer and a resin film provided in this order. The thickness of the first metal layer is 10 nm or greater and 200 nm or less and the surface roughness Rz of a surface opposite to the resin film of the first metal layer is 100 nm or less. It is preferable that the surface roughness Ra of the surface of the resin film opposite to the first metal layer is 30 nm or less.

Description

Conductive film {CONDUCTIVE FILM}

The present invention relates to a conductive film.

Conventionally, a conductive film having a metal layer formed on the surface of a resin film is used for a flexible circuit board, an electromagnetic shielding film, a flat panel display, a touch sensor, a non-contact type IC card, a solar cell, and the like (for example, Patent Document 1). The main function of the conductive film is electrical conduction, and the composition or thickness of the metal layer formed on the surface of the polymer film is appropriately selected so that electrical conductivity intended for the purpose of use is obtained.

Japanese Patent Publication No. 2011-82848

In recent years, as the demand for thinning and miniaturization of device elements has increased, the thickness of the metal layer has also been reduced from several hundred nm to several tens of nm. In addition, in order to increase the functionality of the device and expand the use of the device, a metal layer may be used by patterning by etching or the like. However, when patterning a thin metal layer, a disconnection may occur in a circuit pattern, and this is one of the reasons for lowering productivity and reliability.

An object of the present invention is to provide a conductive film capable of suppressing the occurrence of disconnection during patterning of a metal layer even when a relatively thin metal layer is formed.

As a result of careful examination to solve the above problems, the present inventors have found that pinholes are generated at the point where disconnection of the metal layer occurs, and this pinhole is the cause of disconnection. As a result of further examination, it was found that the above object can be achieved by adopting the following configuration, and the present invention has been completed.

The present invention, in one embodiment,

A first metal layer,

Resin film

And in this order,

The thickness of the first metal layer is 10 nm or more and 200 nm or less,

It is related with the conductive film whose surface roughness Rz of the surface opposite to the said resin film of the said 1st metal layer is 100 nm or less.

In the conductive film, since the surface roughness Rz of the first metal layer is within a predetermined range, occurrence of disconnection can be suppressed even when patterning a relatively thin metal layer of 10 nm or more and 200 nm or less. Although this reason is not certain, it is estimated as follows. The present inventors investigated the cause of the occurrence of pinholes, and found that the number of occurrences of the pinholes increases before and after the conductive film is rolled up into a roll shape after the metal layer is formed. From this, the present inventors speculated that when the conductive film is rolled up, a sharp protrusion in the metal layer collapses due to pressure or winding friction when the roll is rolled up, and a pinhole is generated due to the depression of the protrusion. . The occurrence of pinholes due to collapse of these projections becomes more pronounced when the metal layer is relatively thin (10 nm or more and 200 nm or less), and the mechanical strength of the metal layer is low. From the above findings, it is estimated that the occurrence of pinholes is suppressed by reducing the surface roughness Rz of the surface of the metal layer and eliminating steep protrusions and steps in the metal layer, and as a result, it is also possible to suppress disconnection of the patterned metal layer.

It is preferable that the surface roughness Ra of the surface opposite to the first metal layer of the resin film is 30 nm or less. Since the surface on the opposite side to the first metal layer of the resin film comes into contact with the first metal layer when the conductive film is rolled up in a roll shape, the first metal layer and the resin film are squeezed, and thereafter the metal layer at the time of delivery from the roll There is a possibility of peeling. By controlling the surface roughness Ra of the contact surface of the resin film with the first metal layer within the above range, compression of the first metal layer with the resin film can be suppressed.

It is preferable that the surface roughness Ra of the surface of the resin film on the first metal layer side is 0.5 nm or more and 10 nm or less. Since the surface state of the metal layer tends to inherit the surface state of the resin film as it is, by setting the surface roughness Ra of the resin film to the above range, it is possible to efficiently control the surface roughness Rz on the surface of the metal layer in a predetermined range.

The conductive film may further include a base layer disposed between the resin film and the first metal layer. By forming the underlying layer according to the purpose, such as adhesion of the first metal layer to the resin film, imparting strength to the conductive film, and controlling electrical properties, it is possible to increase the functionality of the conductive film.

In a further embodiment, the conductive film may further include a second metal layer disposed on the opposite side to the first metal layer of the resin film. In this case, it is preferable that the thickness of the second metal layer is 10 nm or more and 200 nm or less, and the surface roughness Rz of the surface opposite to the resin film of the second metal layer is 100 nm or less.

By forming the metal layer on both sides of the resin film, it is possible to achieve high functionality of the conductive film and expansion of use. Further, by setting the surface roughness Rz of the surface of the first metal layer as well as the second metal layer within the above range, it is possible to suppress the occurrence of pinholes by eliminating steep protrusions and steps in the metal layers on both sides, and as a result, patterning The disconnection of the metal layer can be suppressed on both sides.

It is preferable that the surface roughness Ra of the surface of the resin film on the second metal layer side is 0.5 nm or more and 10 nm or less. As in the case of the first metal layer, by setting the surface roughness Ra of the resin film to the above range, the surface roughness Rz of the surface of the second metal layer can be efficiently controlled in a predetermined range.

It is preferable that at least one of the surface roughness Ra of the surface opposite to the resin film of the first metal layer and the surface roughness Ra of the surface opposite to the resin film of the second metal layer is 0.5 nm or more and 10 nm or less. When a conductive film having a metal layer formed on both sides of a resin film is wound in a roll shape, the metal layer on the center side and the metal layer on the outside in the radial direction of the roll also come into contact with the metal layer, and blocking between the metal layers may occur. When the roll of the conductive film is placed under vacuum during sputter film formation of the metal layer, blocking becomes particularly remarkable. By controlling one or both of the surface roughness Ra of the double-sided metal layer to a predetermined range, it is possible to provide an unevenness to the surface of the metal layer, and to suppress the occurrence of pinholes and to prevent blocking.

The conductive film may further include a base layer disposed between the resin film and the second metal layer. By forming the underlying layer according to the purpose, such as adhesion of the second metal layer to the resin film, imparting strength to the conductive film, and controlling electrical properties, it is possible to increase the functionality of the conductive film.

It is preferable that the absolute value of the difference between the thickness of the first metal layer and the thickness of the second metal layer is 5 nm or less. By making the thickness of the metal layers on both sides close to each other, the stress generated in the metal layer is canceled out, and curling of the conductive film or peeling of the metal layer can be prevented.

The conductive film may be wound in a roll form from the viewpoint of conveyability and handling.

1 is a schematic cross-sectional view of a conductive film according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a conductive film according to a further embodiment of the present invention.

EMBODIMENT OF THE INVENTION The embodiment of the conductive film of this invention is demonstrated below, referring drawings. However, in some or all of the drawings, parts unnecessary for explanation are omitted, and there are parts shown by enlargement or reduction to facilitate explanation. Terms indicating the positional relationship such as up and down are used for easy explanation, and there is no intention to limit the configuration of the present invention.

<<first embodiment>>

<Conductive film>

1 is a schematic cross-sectional view of a conductive film according to an embodiment of the present invention. The conductive film 100 shown in FIG. 1 includes the first metal layer 21 and the resin film 1 in this order. In this embodiment, the base layer 31 is formed between the resin film 1 and the first metal layer 21. Moreover, although the 1st metal layer 21 and the base layer 31 show the structure which consists of one layer, respectively, each may have a multilayer structure of two or more layers.

(Resin film)

The resin film 1 is not particularly limited as long as it can secure insulating properties, and various plastic films are used. As the material of the resin film, polyester-based resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyimide-based resins such as polyimide (PI), polyethylene ( PE), polypropylene resin such as polypropylene (PP), acetate resin, polyether sulfone resin, polycarbonate resin, polyamide resin, cycloolefin resin, (meth)acrylic resin, polyvinyl chloride resin , Polyvinylidene chloride-based resin, polystyrene-based resin, polyvinyl alcohol-based resin, polyarylate-based resin, polyphenylene sulfide-based resin, and the like. Among these, polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and polyimide-based resins such as polyimide (PI), from the viewpoints of heat resistance, durability, flexibility, production efficiency, cost, etc. desirable. In particular, from the viewpoint of cost performance, polyethylene terephthalate (PET) is preferred.

The surface of the resin film is previously subjected to etching treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, or primer treatment, and adhesion to a metal layer formed on the resin film. You can also make collateral. Moreover, before forming a metal layer, if necessary, the surface of a resin film may be damped and cleaned by solvent cleaning, ultrasonic cleaning, or the like.

The surface roughness Ra of the surface 12a on the opposite side to the first metal layer 21 of the resin film 1 is preferably 30 nm or less, and more preferably 8 nm or less. The surface roughness Ra of the surface 12a of the resin film 1 is preferably 1.5 nm or more, and more preferably 3 nm or more. The surface 12a on the side opposite to the first metal layer 21 of the resin film 1 may be in contact with the first metal layer 21 when the conductive film 100 is wound in a roll shape, and may be compressed to each other. By controlling the surface roughness Ra of the contact surface (that is, the surface 12a) of the resin film 1 with the first metal layer 21 within the above range, compression of the resin film 1 and the first metal layer 21 is suppressed. can do.

The surface roughness Ra of the surface 11a on the first metal layer 21 side of the resin film 1 is preferably 0.5 nm or more and 10 nm or less. The lower limit of the surface roughness Ra of the surface 11a of the resin film 1 is preferably 1.5 nm, and more preferably 3 nm. On the other hand, the upper limit of the surface roughness Ra of the surface 11a of the resin film 1 is preferably 8 nm, and more preferably 6 nm. Since the surface state of the metal layer tends to inherit the surface state of the resin film 1 as it is, by setting the surface roughness Ra of the resin film 1 to the above range, the surface state of the surface 21a of the first metal layer 21 Surface roughness Rz can be efficiently controlled in a predetermined range.

The thickness of the resin film is preferably in the range of 2 to 200 μm, more preferably in the range of 10 to 100 μm, and more preferably in the range of 20 to 60 μm. In general, a thicker resin film is preferable because it is less susceptible to heat shrinkage during heating. However, it is preferable to make the thickness of the resin film thin to some extent by the compactness of electronic components 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, and water and gas are permeated, and the metal layer is easily oxidized. Therefore, in this embodiment, by making the thickness of the resin film thin while having a certain thickness, the conductive film itself can also be made thin, and it becomes possible to suppress the thickness when used in an electromagnetic shield sheet, sensor, or the like. Therefore, it can cope with thinning of an electromagnetic shield sheet or a sensor. In addition, if the thickness of the resin film is within the above range, the flexibility of the resin film can be ensured while the mechanical strength is sufficient, and the operation of continuously forming the base layer or the metal layer by making the film into a roll is possible.

(Base layer)

The conductive film of the present embodiment further includes a base layer 31 disposed between the resin film 1 and the first metal layer 21. By forming the underlying layer according to the purpose, such as adhesion of the first metal layer to the resin film, imparting strength to the conductive film, and controlling electrical properties, it is possible to increase the functionality of the conductive film. It does not specifically limit as a base layer, The adhesive layer, a hard-coat layer (including what functions as an anti-blocking layer etc.), a dielectric layer, etc. are mentioned.

(Easy adhesive layer)

This adhesive layer is a cured film of an adhesive resin composition. The adhesion layer has good adhesion to the metal layer.

As an adhesive resin composition, what has sufficient adhesiveness and strength as a cured film after formation of an intimate adhesive layer can be used without particular limitation. Examples of the resin to be used include thermosetting resins, thermoplastic resins, ultraviolet curing resins, electron beam curing resins, two-liquid mixed resins, and mixtures thereof. Among these, curing treatment by ultraviolet irradiation is a simple processing operation. UV-curable resins capable of efficiently forming a tight adhesion layer are suitable. By including the ultraviolet curable resin, an adhesive resin composition having ultraviolet curability is easily obtained.

As the adhesive resin composition, a material that forms a crosslinked structure upon curing is preferable. When the crosslinked structure in the cohesive layer is promoted, the internal structure of the film, which has been gentle until then, becomes strong, and the film strength is improved. This is because it is estimated that the improvement of the film strength contributes to the improvement of adhesion.

It is preferable that an adhesive resin composition contains at least 1 sort(s) of a (meth)acrylate monomer and a (meth)acrylate oligomer. Accordingly, it is easy to form a crosslinked structure resulting from a C=C double bond included in the acryloyl group, and it is possible to efficiently improve the film strength. In addition, in this 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 the present embodiment has a role of forming a coating film, and specifically, trimethylolpropane tri(meth)acrylate , Ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, trimethylolpropanetetra(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 And hexa(meth)acrylate 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 mixtures thereof, are wear-resistant and curable. It is particularly preferable in terms of.

Moreover, a urethane acrylate oligomer can also be used. The urethane (meth)acrylate oligomer is a method of reacting a polyol with a polyisocyanate and then reacting a (meth)acrylate having a hydroxyl group, or after reacting a polyisocyanate with a (meth)acrylate having a hydroxyl group, Although a method of reacting a polyol, a method of reacting a polyisocyanate, a polyol, and a (meth)acrylate having a hydroxyl group, etc. may be mentioned, there is no particular limitation.

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. have.

As polyisocyanate, for example, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylenediisocyanate, p-phenylenediisocyanate, hexamethylene diisocyanate, trimethylhexamethylene Diisocyanate, 4,4'-diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,3-xylylenediisocyanate, 1,4-xylylenediisocyanate, and the like.

If the crosslinking density is too high, the performance as a primer decreases and the metal adhesion tends to decrease, so a low-functional (meth)acrylate having a hydroxyl group (hereinafter referred to as a hydroxyl-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, and 2-hydroxypropyl (meth)acrylate. , 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-acryloyloxy Propyl (meth)acrylate, pentaerythritol tri(meth)acrylate, and the like. The above-mentioned (meth)acrylate monomer component and/or (meth)acrylate oligomer component may be used singly or two or more kinds may be used.

The adhesive resin composition having ultraviolet curability of this embodiment improves anti-blocking property by blending a (meth)acrylic group-containing silane coupling agent. Examples of the (meth)acrylic group-containing silane coupling agent include 3-acryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyl dimethoxysilane, 3-methacryloxypropyl trimethoxysilane, and 3-methacryloxypropyl. Methyl diethoxysilane, 3-methacryloxypropyl triethoxysilane, and the like, and commercially available products include KR-513 and KBM-5103 (manufactured by Shin-Etsu Chemical Co., Ltd.).

The blending amount of the silane coupling agent is 0.1 to 50 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the (meth)acrylate monomer and/or (meth)acrylate oligomer. If it is within this range, adhesion to the metal layer is improved, and the coating film properties can be maintained.

The tight adhesion layer of this embodiment may contain nano-silica fine particles. As the nano-silica fine particles, an organo silica sol synthesized with an alkylsilane or a nano-silica synthesized by plasma arc can be used. As a commercial item, PL-7-PGME (Fuso Chemical Manufacturing, brand name) is the former, and SIRMIBK15WT%-M36 (made by CIK Nanotech, a brand name) etc. are mentioned. The blending ratio of the nano-silica fine particles is preferably 5 to 30 parts by weight, and preferably 5 to 5 parts by weight based on 100 parts by weight of the (meth)acrylate monomer and/or acrylate oligomer and silane coupling agent having the (meth)acryloyl group. 10 parts by weight is more preferable. By setting it as a lower limit or more, surface irregularities are formed, and anti-blocking properties can be imparted, and roll-to-roll production is possible. Decreasing adhesiveness with a metal layer can be prevented by setting below an upper limit.

The average particle diameter of the nano-silica fine particles is preferably 100 to 500 nm. When the average particle diameter is less than 100 nm, the amount of addition required for forming the unevenness on the surface increases, whereas the adhesion with the metal layer is not obtained, whereas when it exceeds 500 nm, the unevenness of the surface becomes large and pinhole problems occur.

It is preferable that the adhesive resin composition contains a photopolymerization initiator in order to impart ultraviolet curability. Examples of the photopolymerization initiator include benzoin ethers such as benzoin-normal butyl ether and benzoin isobutyl ether, benzyl dimethyl ketals, benzyl diethyl ketals and other benzyl ketals, and 2,2-dimethoxyacetophenone, 2,2 -Acetophenones such as diethoxy acetophenone, 1-hydroxycyclohexylphenylketone, [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 Α-hydroxyalkylphenones such as -2-methyl-1-(4-isopropylphenyl)propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-1-morpholino Α-aminoalkylphenones such as propane and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2 Monoacylphosphine oxides such as ,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4 And monoacylphosphine oxides such as ,6-trimethylbenzoyl)phenylphosphine oxide.

From the viewpoint of curability of the resin, light stability, compatibility with the resin, low volatility, and low odor, an alkylphenone-based photopolymerization initiator is preferable, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl- 1-phenyl-propan-1-one, (2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propane-1 -On, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one is more preferable. As commercial products, Irgacure127, 184, 369, 651, 500, 891, 907, 2959, Darocure1173, TPO (manufactured by BASF Japan, trade name), etc. The photopolymerization initiator is a (meth)acrylate monomer having a (meth)acryloyl group and/or acrylate Based on 100 parts by weight of the oligomer, 3 to 10 parts by weight of solid content is blended.

When forming the adhesive layer, an adhesive resin composition containing (meth)acrylate and/or (meth)acrylate oligomer having a (meth)acryloyl group in the molecule as a main component, toluene, butyl acetate, isobutanol, Diluted in solvents such as ethyl acetate, cyclohexane, cyclohexanone, methylcyclohexanone, hexane, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, diethyl ether, ethylene glycol, and solid content is 30 It is prepared as a varnish of -50%.

The self-adhesive layer is formed by applying the varnish on the cycloolefin-based resin film (1). The varnish application method can be selected in a timely manner depending on the conditions of the varnish and the coating process, for example, dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, or die coating. It can be applied by a method, an extrusion coat method, or the like.

After coating the varnish, the coating film can be cured to form a self-adhesive layer. As the curing treatment of the adhesive resin composition having ultraviolet curability, when the varnish contains a solvent, after removing the solvent by drying (for example, at 80°C for 1 minute), 500 mW/cm 2 to 3000 using an ultraviolet irradiator As an irradiation intensity of mW/cm 2, a procedure of curing by applying ultraviolet light treatment having a work volume of 50 to 400 mJ/cm 2 is cured. Ultraviolet lamps are generally used as the ultraviolet generator, and specifically, low pressure mercury lamps, high pressure mercury lamps, ultra high pressure mercury lamps, xenon lamps, metal halide lamps, etc. may be used. , Inert gas such as argon.

It is preferable to perform heating at the time of ultraviolet curing treatment. 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, the formation of a crosslinked structure can be sufficiently promoted even with a low ultraviolet dose. The heating temperature can be set depending on the degree of crosslinking, and is preferably 50°C to 80°C. The heating means is not particularly limited, and a warm air dryer, a radiant heat dryer, heating of a film transfer roll, or the like can be suitably employed.

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

(Hard coat layer)

As the base layer, a hard coat layer may be formed. Further, in order to prevent blocking between conductive films and to enable production by a roll-to-roll method, particles may be blended in the hard coat layer.

For formation of the hard coat layer, an adhesive composition similar to that of the adhesion layer can be suitably used. To impart anti-blocking properties, it is preferable to blend particles in the adhesive composition. Thereby, unevenness|corrugation can be formed in the surface of a hard-coat layer, and anti-blocking property can be suitably provided to the electroconductive film 100.

As the particles, those having transparency such as various metal oxides, glass, and plastics can be used without particular limitation. For example, inorganic particles such as silica, alumina, titania, zirconia, calcium oxide, polymethyl methacrylate, polystyrene, polyurethane, acrylic resin, acrylic-styrene copolymer, benzoguanamine, melamine, polycarbonate, etc. And crosslinked or uncrosslinked organic particles made of polymer, silicon particles, and the like. The said particle|grains can be used selecting 1 type or 2 or more types suitably.

The average particle diameter and the blending amount of the particles can be appropriately set while considering the degree of surface irregularities. 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 resin solid content of a composition.

(Dielectric layer)

As the base layer, one or more dielectric layers may be provided. The dielectric layer is formed of an inorganic substance, an organic substance, or a mixture of an inorganic substance and an organic substance. A material for forming the dielectric _{layer, NaF, N a3 AlF 6,} LiF, MgF 2, CaF 2, SiO 2, LaF 3, CeF 3, Al 2 O 3, TiO 2, Ta 2 O 5, ZrO 2, ZnO, And inorganic substances such as 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 polymers. In particular, it is preferable to use a thermosetting resin composed of a mixture of a melamine resin, an alkyd resin, and an organic silane condensate as an organic material. The dielectric layer can be formed 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, using the above-mentioned material.

The thickness of the dielectric layer is preferably 10 nm to 200 nm, more preferably 20 nm to 150 nm, and even more preferably 20 nm to 130 nm. If the thickness of the dielectric layer is excessively small, it is difficult to form a continuous film. Moreover, when the thickness of the dielectric layer is excessively large, cracks are likely to occur in the dielectric layer.

The dielectric layer may have nano fine particles having an average particle diameter of 1 nm to 500 nm. The content of the nano fine particles in the dielectric layer is preferably 0.1% by weight to 90% by weight. As described above, 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. Moreover, it is more preferable that content of the nanoparticles in a dielectric layer is 10 weight%-80 weight%, and it is still more preferable that it is 20 weight%-70 weight%.

Examples of the inorganic oxide forming the nanoparticles include microparticles such as silicon oxide (silica), hollow nano silica, 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 preferable. These may be used individually by 1 type and may use 2 or more types together.

(First metal layer)

The first metal layer 21 formed on one surface 11a side of the resin film 1 preferably has an electrical resistivity of 50 μΩcm or less in order to sufficiently obtain an electromagnetic wave shielding effect or a sensor function. The material of the metal layer is not particularly limited as long as it satisfies such electrical resistivity and has conductivity. For example, Cu, Al, Fe, Cr, Ti, Si, Nb, In, Zn, Sn, Au, Ag Metals such as, Co, Cr, Ni, Pb, Pd, Pt, W, Zr, Ta, Hf, Mo, Mn, Mg, V are suitably used. Moreover, what contains 2 or more types of these metals, the alloy etc. which have these metals as a main component can also be used. Among these metals, it is preferable to contain Cu and Al from the viewpoint of high conductivity and relatively low cost contributing to electromagnetic wave shielding characteristics and sensor functions. In particular, from the viewpoint of cost performance and production efficiency, it is preferable to include Cu, but elements other than Cu may contain impurities. Accordingly, since the electrical resistivity is sufficiently small and the conductivity is high, it is possible to improve electromagnetic wave shielding characteristics and sensor functions.

The formation method of the 1st metal layer 21 is not specifically limited, A conventionally well-known method can be employ|adopted. Specifically, for example, from the viewpoint of film thickness uniformity and film formation efficiency, vacuum film forming methods such as sputtering, chemical vapor deposition (CVD), physical vapor deposition (PVD), ion plating, plating It is preferable to form a film by (electrolytic plating, electroless plating), hot stamping, coating or the like. Further, a plurality of these film forming methods may be combined, or an appropriate method may be employed depending on the required film thickness. Especially, the sputtering method and the vacuum film forming method are preferable, and the sputtering method is especially preferable. Thereby, since it can be continuously produced by the roll-to-roll manufacturing method, the production efficiency can be increased and the film thickness at the time of film formation can be controlled, so that the increase in the surface resistance value of the conductive film can be suppressed. Further, a thin, uniform film thickness and a dense metal layer can be formed.

The thickness of the first metal layer 21 is 10 nm or more and 200 nm or less. The lower limit of the thickness of the first metal layer 21 is preferably 20 nm, and more preferably 50 nm. On the other hand, the upper limit of the thickness of the first metal layer 21 is preferably 160 nm. When the thickness of the first metal layer 21 exceeds the above upper limit, curling of the conductive film after heating tends to occur, or the thickness of the device becomes difficult. If the thickness is smaller than the above lower limit, the surface resistance value of the conductive film is likely to be high resistance under humidification heat conditions, so that targeted humidification heat reliability is not obtained, or peeling of the pattern wiring occurs due to a decrease in the strength of the metal layer. Or

The surface roughness Rz of the surface 21a on the opposite side to the resin film 1 of the first metal layer 21 is 100 nm or less. The surface roughness Rz of the surface 21a of the first metal layer 21 is preferably 90 nm or less, and more preferably 70 nm or less. On the other hand, the surface roughness Rz of the surface 21a of the first metal layer 21 is preferably 1 nm or more, more preferably 10 nm or more, and even more preferably 30 nm or more. By setting the surface roughness Rz of the surface 21a of the first metal layer 21 to the above range, steep protrusions or steps in the first metal layer 21 can be eliminated, and pinhole generation is suppressed. As a result, The disconnection of the patterned metal layer can also be suppressed.

(Protective layer)

The protective layer can be formed on the outermost surface 21a side of the first metal layer 21 to prevent the first metal layer 21 from being naturally oxidized under the influence of oxygen in the atmosphere (not shown). Not). The protective layer is not particularly limited as long as it exhibits a rust-preventing effect of the first metal layer 21, but a sputterable metal is preferable, and Ni, Cu, Ti, Si, Zn, Sn, Cr, Fe, and indium , Gallium, antimony, zirconium, magnesium, aluminum, gold, silver, palladium, tungsten, or any one or more metals or oxides thereof. Because Ni, Cu, and Ti do not corrode well because they form a passivation layer, Si does not corrode well because of improved corrosion resistance, and Zn and Cr are metals that do not corrode well because they form a dense oxide film on the surface. desirable.

As a material for the protective layer, an alloy made of two kinds of metals can be used, although three or more kinds of metals can be used from the viewpoint of ensuring the adhesion to the first metal layer 21 and reliably preventing rust of the first metal layer 21. An alloy made of metal is preferred. Examples of alloys composed of three or more types of metals include Ni-Cu-Ti, Ni-Cu-Fe, Ni-Cu-Cr, and the like, and Ni-Cu-Ti is preferred from the viewpoint of rust prevention function and production efficiency. Do. Moreover, it is preferable that it is an alloy containing the forming material of the 1st metal layer 21 from a viewpoint of ensuring the adhesiveness with the 1st metal layer 21. Thereby, oxidation of the 1st metal layer 21 can be prevented reliably.

Further, as the material of the protective layer, for example, indium-doped tin oxide (ITO), antimony-containing tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped oxide Zinc (IZO) may be included. It is preferable not only to suppress an increase in the initial surface resistance value of the conductive film, but also to suppress an increase in the surface resistance value under humidifying and heating conditions, and to stabilize the surface resistance value optimally.

As the oxide of the metal, oxides such as SiO _x (x = 1.0 to 2.0), copper oxide, silver oxide, and titanium oxide are preferable. Further, instead of the above-described metal, alloy, oxide, etc., it is also possible to bring the anti-corrosive effect by forming a resin layer such as an acrylic resin or an epoxy resin on the first metal layer 21.

The film thickness of the protective layer is preferably 1 to 50 nm, more preferably 2 to 30 nm, and preferably 3 to 20 nm. Thereby, since the durability is improved and oxidation can be prevented from the surface layer, the increase in the surface resistance value under humidifying heat conditions can be suppressed.

<<second embodiment>>

In the first embodiment, a metal layer is formed on one side of the resin film, whereas in the second embodiment, a metal layer is formed on both sides of the resin film. Since the layer structure formed on the other side of the resin film in this embodiment is the same as that in the first embodiment, features characteristic of this embodiment will be mainly described below.

2 is a schematic cross-sectional view of a conductive film according to a further embodiment of the present invention. The conductive film 200 shown in FIG. 2 includes a first metal layer 21 and a resin film 1, and a second metal layer disposed on the opposite side to the first metal layer 21 of the resin film 1 (22) is provided (hereinafter, in the case where the first metal layer and the second metal layer are not distinguished, it may be simply referred to as a "metal layer"). In the present embodiment, the base layer 31 formed between the resin film 1 and the first metal layer 21, and in addition, the base layer 32 is also formed between the resin film 1 and the second metal layer 22. (Hereinafter, when not distinguishing the underlayers on both sides, it may be referred to simply as "underlayer"). However, the base layer need not be formed on both surfaces of the resin film 1, and may be formed on either side.

The forming material and layer structure of the second metal layer 22 and the base layer 32 in this embodiment are basically the same as those of the first metal layer 21 and the base layer 31 in the first embodiment. It can be suitably employed.

The surface roughness Ra of the surface 12a on the second metal layer 22 side of the resin film 1 is preferably 0.5 nm or more and 10 nm or less. The lower limit of the surface roughness Ra of the surface 12a of the resin film 1 is preferably 1.5 nm, and more preferably 3 nm. On the other hand, the upper limit of the surface roughness Ra of the surface 12a of the resin film 1 is preferably 8 nm, and more preferably 6 nm. Since the surface state of the metal layer tends to inherit the surface state of the resin film 1 as it is, by setting the surface roughness Ra of the resin film 1 to the above range, the surface state of the surface 22a of the second metal layer 22 Surface roughness Rz can be efficiently controlled in a predetermined range. In addition, the surface roughness Ra of both surfaces of the resin film 1 may be the same or different from each other.

The thickness of the second metal layer 22 is 10 nm or more and 200 nm or less. The lower limit of the thickness of the second metal layer 22 is preferably 20 nm, and more preferably 50 nm. On the other hand, the upper limit of the thickness of the second metal layer 22 is preferably 160 nm. When the thickness of the second metal layer 22 exceeds the above upper limit, curling of the conductive film after heating tends to occur, or the thickness of the device becomes difficult. If the thickness is smaller than the above lower limit, the surface resistance value of the conductive film is likely to be high resistance under humidification heat conditions, so that targeted humidification heat reliability is not obtained, or peeling of the pattern wiring occurs due to a decrease in the strength of the metal layer. Or In addition, the thicknesses of the metal layers on both sides may be the same or different from each other.

The surface roughness Rz of the surface 22a on the opposite side to the resin film 1 of the second metal layer 22 is 100 nm or less. The surface roughness Rz of the surface 22a of the second metal layer 22 is preferably 90 nm or less, and more preferably 70 nm or less. On the other hand, the surface roughness Rz of the surface 22a of the second metal layer 22 is preferably 1 nm or more, more preferably 10 nm or more, and even more preferably 30 nm or more. By making the surface roughness Rz of the surface 22a of the second metal layer 22 within the above range, steep protrusions or steps in the second metal layer 22 can be eliminated, and the occurrence of pinholes is suppressed. As a result, The disconnection of the patterned metal layer can also be suppressed. Moreover, the surface roughness Rz of the metal layer of both surfaces may mutually be same or different.

Among the surface roughness Ra of the surface 21a opposite to the resin film 1 of the first metal layer 21 and the surface roughness Ra of the surface 22a opposite the resin film 1 of the second metal layer 22 It is preferable that at least one is 0.5 nm or more and 10 nm or less. The surface roughness Ra is more preferably 1.5 nm or more, and even more preferably 3 nm or more. On the other hand, the surface roughness Ra is more preferably 8 nm or less, and even more preferably 6 nm or more. By controlling one or both of the surface roughness Ra of the double-sided metal layer to a predetermined range, it is possible to provide an unevenness to the surface of the metal layer, and to suppress the occurrence of pinholes and to prevent blocking. Further, the surface roughness Ra of the metal layers on both sides may be the same or different from each other.

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

(Characteristics of conductive film)

The initial surface resistance value R ₁ of the conductive films 100 and 200 is preferably 0.001 Ω/□ to 10.0 Ω/□, more preferably 0.01 Ω/□ to 3.5 Ω/□, and 0.1 Ω/□ It is more preferably from 1.0 to Ω/□. Accordingly, it is possible to provide a practical conductive film having excellent production efficiency.

The thickness of the conductive films 100 and 200 is preferably in the range of 2 to 200 μm, more preferably in the range of 10 to 100 μm, and more preferably in the range of 20 to 60 μm. Thereby, the conductive film itself can also be made thin, and it becomes possible to suppress the thickness when used in an electromagnetic shield sheet, sensor, or the like. Therefore, it can cope with thinning of an electromagnetic shield sheet or a sensor. In addition, if the thickness of the conductive film is within the above range, mechanical strength can be sufficiently secured while ensuring flexibility, and the operation of continuously forming a Si-containing layer or a metal layer, etc. by making the film into a roll becomes easy, and production efficiency is improved. do.

The conductive films 100 and 200 may be wound in a roll form from the viewpoint of conveyability and handling. By continuously forming a base layer and a metal layer on a resin film by a roll-to-roll method, a conductive film can be efficiently produced.

(Use of conductive film)

The conductive films 100 and 200 may be applied to various uses, and may be applied to, for example, an electromagnetic shield sheet or a planar sensor. The electromagnetic shielding sheet is a conductive film, and can be suitably used in the form of a touch panel or the like. It is preferable that the thickness of the electromagnetic wave shield sheet is 20 μm to 300 μm.

In addition, 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 seen in the lamination direction (the same direction as the thickness direction of the sheet) is square, circular, triangular, polygonal, etc. , It can be selected as an appropriate shape.

The planar sensor is a conductive film, and includes sensors for sensing various physical quantities in addition to user interface applications such as a touch panel or controller of a mobile device. The thickness of the planar sensor is preferably 20 μm to 300 μm.

Example

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

<Example 1>

First, a long-length resin composed of a polyethylene terephthalate film having a width of 1.100 m, a length of 2500 m, and a thickness of 150 µm (manufactured by Toray Film Processing Co., Ltd., product name "150-TT00A", hereinafter referred to as PET film.) The film was wound around a delivery roll and installed in a sputtering device. Thereafter, the inside of the sputtering apparatus was made into a high vacuum of 3.0 x 10 ^-3 Torr, and in this state, sputter film formation was performed while sending a long resin film from a feeding roll to a winding roll. In an atmosphere of 3.0 x 10 ^-3 Torr consisting of 100% by volume of Ar gas, a Cu target material was used to form a metal layer sputtered on both sides with a thickness of 150 nm by a sintered body DC magnetron sputtering method, and a film on a delivery roll. By winding up, the wound body of the electroconductive film was produced.

<Example 2>

A wound body of a conductive film was produced in the same manner as in Example 1, except that the metal layer was sputter-deposited on both sides with a thickness of 100 nm.

<Comparative Example 1>

A wound body of a conductive film was produced in the same manner as in Example 1, except that the metal layer was sputter-deposited on both sides with a thickness of 300 nm.

<Comparative Example 2>

A wound body of a conductive film was produced in the same manner as in Example 1 except that a polyethylene terephthalate film having a thickness of 38 µm (Mitsubishi Resin Co., Ltd. product name "TA-38T613N") was used.

<Evaluation>

The following evaluation was performed about the produced conductive film. Table 1 shows the results.

(1) Measurement of thickness

The thickness of the metal layer was measured by observing the cross section of the conductive film using a transmission electron microscope (manufactured by Hitachi, product name "H-7650").

(2) Measurement of surface roughness Ra and surface roughness Rz of the metal layer

The surface roughness Ra and the surface roughness Rz of the metal layer on both surfaces were measured using AFM (atomic force microscope, Bruker, "Dimemsion Edge+NanoDrive"). The measurement results were the same on both sides. The measurement was performed at five points at random on the sheet-like film cut out from an arbitrary position of the roll-shaped film, and was carried out by taking their average value.

(3) Measurement of surface roughness Ra of the resin film

The surface roughness Ra of the resin film before the formation of the metal layer was measured using AFM (atomic force microscope, manufactured by Bruker, "Dimemsion Edge+NanoDrive"). The measurement results were the same on both sides. The measurement was performed at five points at random on the sheet-like film cut out from an arbitrary position of the roll-shaped film, and was carried out by taking their average values.

(5) Evaluation of the presence or absence of pinholes

A mask tape was applied to one side of the metal layer, and a solution (etchant) in which 8 parts by weight of ammonium chloride was mixed with respect to 100 parts by weight of aqueous ammonia (concentration 8% by weight) was used to etch in a predetermined pattern and water Washed and dried. The presence or absence of pinholes in the metal layer patterned with a light table (manufactured by Hakuba Corporation, "KLV7000") was confirmed. The presence or absence of pinholes was judged by the following evaluation criteria.

"Evaluation standard"

○: No pinhole

△: Part of the copper wiring is disconnected at the pinhole.

×: The copper wiring is completely disconnected at the pinhole.

(6) Evaluation of the presence or absence of blocking

A roll-shaped conductive film was installed in the sputtering apparatus, and the inside of the sputtering apparatus was set to a high vacuum of 3.0 x 10 ^-3 Torr, and in this state, a long conductive film was sent out, and the roll surface was confirmed. The presence or absence of blocking (transportability) was judged by the following evaluation criteria.

"Evaluation standard"

○: No scratches were observed on the roll surface.

×: Scratches were observed on the roll surface.

(Results and Discussion)

In the conductive film of the example, the occurrence of pinholes was suppressed, and the anti-blocking property was good. On the other hand, in Comparative Example 1, although anti-blocking property was good, many pinholes were generated. This is because the surface roughness of the metal layer is too large and there are steep protrusions, but the anti-blocking property is exhibited, but it is presumed that the protrusions collapsed and collapsed during roll-up. In Comparative Example 2, the occurrence of pinholes was suppressed, but the anti-blocking property was poor. This is presumed to be due to the fact that the surface roughness of the metal layer is too small and the smooth metal layers are bonded together.

1: Resin film
100: conductive film
11a: Surface of the conductive film on the first metal layer side
12a: Surface of the conductive film opposite to the first metal layer (the second metal layer side)
21: 1st metal layer
21a: The surface opposite to the resin film of the first metal layer
22: second metal layer
22a: The surface opposite to the resin film of the second metal layer
31, 32: Underground

Claims (10)

A first metal layer,
Resin film
And in this order,
The thickness of the first metal layer is 10 nm or more and 200 nm or less,
The conductive film whose surface roughness Rz of the surface opposite to the said resin film of the said 1st metal layer is 100 nm or less. According to claim 1,
The conductive film whose surface roughness Ra of the surface opposite to the said 1st metal layer of the said resin film is 30 nm or less. The method according to claim 1 or 2,
The conductive film whose surface roughness Ra of the surface of the said 1st metal layer side of the said resin film is 0.5 nm or more and 10 nm or less. The method according to any one of claims 1 to 3,
A conductive film further comprising an underlayer disposed between the resin film and the first metal layer. The method according to any one of claims 1 to 4,
Further comprising a second metal layer disposed on the opposite side to the first metal layer of the resin film,
The thickness of the second metal layer is 10 nm or more and 200 nm or less,
The conductive film whose surface roughness Rz of the surface opposite to the said resin film of the said 2nd metal layer is 100 nm or less. The method of claim 5,
The conductive film whose surface roughness Ra of the surface of the said 2nd metal layer side of the said resin film is 0.5 nm or more and 10 nm or less. The method of claim 5 or 6,
At least one of the surface roughness Ra of the surface on the opposite side to the resin film of the first metal layer and the surface roughness Ra of the surface on the opposite side to the resin film of the second metal layer is a conductive film of 0.5 nm or more and 10 nm or less. The method according to any one of claims 5 to 7,
A conductive film further comprising a base layer disposed between the resin film and the second metal layer. The method according to any one of claims 5 to 8,
The conductive film in which the absolute value of the difference between the thickness of the first metal layer and the thickness of the second metal layer is 5 nm or less. The method according to any one of claims 1 to 9,
A conductive film wound in a roll shape.

Images