JP6737933B2 - Conductive film - Google Patents

Description

The present invention relates to a conductive film.

Conventionally, a conductive film in which a conductive layer is formed on a surface of a resin film such as a PET film by fusing, plating, or vapor deposition of a metal foil on functional elements such as an electromagnetic wave shield sheet, a flat panel display, a sensor, and a solar cell. It is used. Cu is often used for the conductive layer because it has a low electric resistivity and is inexpensive (Patent Document 1, etc.).

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

JP, 2005-056321, A Patent No. 5697223

As part of higher functionality of functional devices, lower resistance of conductive films is required. Although it is possible to meet such requirements by increasing the thickness of the conductive layer, in the case where the conductive layer formed as a thick film is peeled from the resin film of the conductive layer even if the coating film is provided. It is known that there is.

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

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

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

In the conductive film, an easy-adhesion layer that is a cured film of the adhesive resin composition is provided between the polyester-based resin film and the conductive layer, and the surface of the easy-adhesion layer has a predetermined absorbance ratio by FT-IR measurement. Since it is 1.10 or less, sufficient adhesion can be secured even if the conductive layer is a thick film.

Although the mechanism by which the adhesion is improved by controlling the absorbance ratio of the easy-adhesion layer by FT-IR measurement is not clear, it is presumed that one of the factors is the promotion of the crosslinked structure in the easy-adhesion layer and the improvement of the film strength based on this. To be done. From the relationship between the absorbance ratio at FT-IR measurement, the absorbance _{Ab 1410} at 1410 cm ^-1 attributable to the C = C-H, as will become smaller than the absorbance _{Ab 1450} at 1450 cm ^-1 due to C-H Controlled. Since the absorbance has a constant proportional relationship with the abundance of the bond of interest, the fact that the absorbance Ab _{1410 at 1410} cm ⁻¹ is small means that the abundance of C═C—H bonds attributed to the peak is small. It corresponds to that. In the process of forming the easy-adhesion layer, the C=C double bond in the C=C-H bond is bonded with other C=C double bond in the system by radical addition reaction to form a kind of crosslinked structure. As a result, the crosslinked structure in the easy-adhesion layer is promoted. The fact that the C=C double bond is cleaved and consumed to form a crosslinked structure means that the abundance of C=C-H bonds is reduced. Therefore, the present invention is based on such a correlation. It defines a predetermined absorbance ratio.

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

It is preferable that the surface of the easy-adhesion layer has a wetting tension of 45 dyn/cm or less. By setting the surface wetting tension of the easy-adhesion layer in the above range, the surface free energy of the easy-adhesion layer decreases, in other words, the easy-adhesion layer easily wets the conductive layer, and adheres to the conductive layer containing copper. It is possible to further improve the sex.

It is preferable that the adhesive resin composition contains at least one of a (meth)acrylate monomer and a (meth)acrylate oligomer. This facilitates the formation of a crosslinked structure due to the C=C double bond contained in the acryloyl group, and can efficiently improve the film strength.

It is preferable that the adhesive resin composition has ultraviolet curability. Thereby, while avoiding thermal damage to the polyester-based resin film and the conductive layer in the case of heat curing, it is possible to promote the formation of the crosslinked structure only by irradiating with ultraviolet rays, so that stable and efficient conductive Film can be formed.

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

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

An anti-blocking layer may be provided on the other surface side of the polyester resin film.

It is a typical sectional view of a conductive film concerning one embodiment of the present invention.

Embodiments of the conductive film of the present invention will be described below with reference to the drawings. However, in some or all of the drawings, portions unnecessary for description are omitted, and there are portions illustrated in an enlarged or reduced form for ease of explanation. The terms indicating the positional relationship such as the upper and lower sides are used merely for facilitating the description, and have no intention to limit the configuration of the present invention.

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

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

The resin film is subjected to etching treatment such as sputtering, corona discharge, flame, ultraviolet ray irradiation, electron beam irradiation, chemical conversion, oxidation, or undercoating on the surface in advance, and the adhesion with the easy-adhesion layer formed on the resin film. May be improved. In addition, before forming the easy-adhesion layer, the surface of the resin film may be removed and cleaned by solvent cleaning or ultrasonic cleaning, if necessary.

Although the thickness of the resin film is not particularly limited, it is preferably in the range of 2 to 200 μm, more preferably in the range of 10 to 100 μm, and further preferably in the range of 20 to 60 μm. In general, a thicker resin film is desirable because it can suppress heat shrinkage during heating and maintain the adhesiveness of the conductive layer. However, it is desirable to reduce the thickness of the resin film to some extent as electronic parts are made more compact. On the other hand, when the thickness of the resin film is too thin, the handling property of the conductive film is deteriorated. 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 film is rolled to continuously form an easily adhering layer or a conductive layer. Can be operated.

(Easy adhesion layer)
The easy-adhesion layer 2 is a cured film of an adhesive resin composition. 1410 cm ⁻ attributable to C=C−H when FT-IR measurement was performed on the surface of the easy-adhesion layer 2 opposite to the resin film 1 side (hereinafter, also simply referred to as “surface of easy-adhesion layer”). ^The absorbance ratio (Ab ₁₄₁₀ /Ab ₁₄₅₀ ) to the absorbance Ab _{1450 at 1450} cm ⁻¹ due to C—H of the absorbance Ab ₁₄₁₀ at ¹ is 1.10. The absorbance ratio is more preferably 1.08 or less. By setting the absorbance ratio within the specific range, sufficient adhesion can be secured even when the conductive layer is a thick film. On the other hand, when the cross-linking structure is excessively formed in the easy-adhesion layer, the easy-adhesion layer becomes brittle and the adhesion is lowered, or the adhesive resin composition for forming the easy-adhesion layer has ultraviolet curability. Moreover, excessive irradiation of ultraviolet rays may cause deterioration of the resin film. From the viewpoint of preventing these, the absorbance ratio is preferably 0.93 or more, and more preferably 1.0 or more.

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

As the adhesive resin composition, one having sufficient adhesiveness and strength as a cured film after formation of the easy-adhesion layer can be used without particular limitation. Examples of the resin used include thermosetting resin, thermoplastic resin, ultraviolet curable resin, electron beam curable resin, two-component mixed resin, and mixtures thereof. Among these, curing treatment by ultraviolet irradiation is also included. Therefore, an ultraviolet curable resin that can efficiently form an easy-adhesion layer with a simple processing operation is preferable. By containing the ultraviolet curable resin, an adhesive resin composition having ultraviolet curability can be easily obtained.

The adhesive resin composition preferably contains at least one of a (meth)acrylate monomer and a (meth)acrylate oligomer. This facilitates the formation of a crosslinked structure due to the C=C double bond contained in the acryloyl group, and can efficiently improve 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 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, 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 Examples thereof include modified dipentaerythritol tetra(meth)acrylate, alkyl modified dipentaerythritol penta(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, and a mixture of two or more thereof.

Among the above-mentioned (meth)acrylates, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, or a mixture thereof is used from the viewpoint of abrasion resistance and curability. Especially preferred.

A urethane acrylate oligomer can also be used. The urethane (meth)acrylate oligomer is obtained by reacting a polyol with a polyisocyanate and then reacting with a (meth)acrylate having a hydroxyl group, or after reacting a polyisocyanate with a (meth)acrylate having a hydroxyl group. Examples thereof include, but are not limited to, a method of reacting a polyol, a method of reacting a polyisocyanate, a polyol, and a (meth)acrylate having a hydroxyl group.

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

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

If the crosslink 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 group-containing (meth)acrylate) may be used. Examples of the hydroxyl group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. , 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate and the like. .. The above-mentioned (meth)acrylate monomer component and/or (meth)acrylate oligomer component may be used alone or in combination of two or more kinds.

The ultraviolet-curable adhesive resin composition of the present embodiment preferably contains a thiourea-type silane coupling agent as the silane coupling agent. This improves the adhesion of the conductive layer as a primer. The thiourea-type silane coupling agent is an alkoxysilane coupling agent having a structure represented by the following general formula (1), and commercially available products include X-12-1016M, X-12-1111, X-12-1116 and X. -12-1117 (manufactured by Shin-Etsu Chemical Co., Ltd., trade name).

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

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

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

The easy-adhesion layer 2 of the present embodiment may contain nano silica fine particles. As the nano silica fine particles, an organo silica sol synthesized from alkylsilane or nano silica synthesized by plasma arc can be used. Examples of commercially available products include PL-7-PGME (manufactured by Fuso Kagaku, trade name) for the former, and SIRMIBK15WT%-M36 (manufactured by CIK Nanotech, trade name) for the latter. The compounding ratio of the nano silica fine particles is preferably 5 to 30 parts by weight with respect to 100 parts by weight of the total weight of the (meth)acrylate monomer and/or acrylate oligomer having a (meth)acryloyl group and the silane coupling agent, and preferably 5 to 10 parts. More preferably parts by weight. When the content is at least the lower limit, surface irregularities are formed and antiblocking properties can be imparted, and roll-to-roll production is possible. When the content is at most the upper limit, it is possible to prevent a decrease in adhesiveness with the conductive layer.

The average particle size of the nano silica fine particles is preferably 100 to 500 nm. When the average particle size is less than 100 nm, the amount of addition necessary for forming irregularities on the surface is large, and thus adhesion to the conductive layer cannot be obtained, whereas when it exceeds 500 nm, haze becomes large and visibility is deteriorated. Problem occurs.

The adhesive resin composition preferably 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 ketals such as benzyl dimethyl ketal and benzyl diethyl ketal, and acetophenone such as 2,2-dimethoxyacetophenone and 2,2-diethoxyacetophenone. , 1-hydroxycyclohexyl phenyl ketone, [2-hydroxy-2-methyl-1-(4-ethylenephenyl)propan-1-one], 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-(4-isopropylphenyl)propan-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, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, monoacylphosphine oxides such as 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis(2,6- Examples thereof include monoacylphosphine oxides such as dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

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

When forming the easy-adhesion 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 is mixed with toluene, butyl acetate, and Prepared as a varnish with a solid content of 30 to 50% by diluting it with a solvent such as butanol, ethyl acetate, cyclohexane, cyclohexanone, methylcyclohexanone, hexane, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, diethyl ether, ethylene glycol. To do.

The easy-adhesion layer 2 is formed by applying the varnish on the polyester resin film 1. The method of applying the varnish can be appropriately selected depending on the situation of the varnish and the coating process, and examples thereof include a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, and a die coating method. Can be applied by a coating method or an extrusion coating method.

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

It is preferable to perform heating during the ultraviolet curing treatment. The ultraviolet light irradiation advances the curing reaction of the adhesive resin composition and simultaneously forms a crosslinked structure. By heating at this time, the formation of a crosslinked structure can be sufficiently promoted even with a low ultraviolet ray amount, and a desired absorbance ratio can be efficiently achieved. The heating temperature can be set according to 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 transport roll, or the like can be appropriately adopted.

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

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

The method for forming the conductive layer 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, a vacuum film formation method such as a sputtering method, a chemical vapor deposition method (CVD) or a physical vapor deposition method (PVD), or an ion plating method. The film is preferably formed by a coating method, a plating method (electrolytic plating, electroless plating), a hot stamping method, a coating method, or the like. Further, a plurality of these film forming methods may be combined, and an appropriate method may be adopted depending on the required film thickness. Among them, the sputtering method and the vacuum film forming method are preferable, and the sputtering method is particularly preferable. As a result, continuous production can be performed by the roll-to-roll manufacturing method, production efficiency can be increased, and the film thickness at the time of film formation can be controlled, so that an increase in surface resistance of the conductive film can be suppressed. Further, a dense conductive layer which is thin and has a uniform film thickness can be formed.

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

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

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

Examples of the material 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 not only the initial increase in the surface resistance value of the conductive film can be suppressed, but also the increase in the surface resistance value under the humidified heat condition can be suppressed, and the stabilization of the surface resistance value can be optimized.

The metal oxide is preferably an oxide such as SiOx (x=1.0 to 2.0), copper oxide, silver oxide, or titanium oxide, but from the viewpoint of stabilizing the surface resistance value of the conductive film. , SiOx (x=1.0 to 2.0) are particularly preferable. This makes the conductive layer less likely to be corroded. It is also possible to provide a rust preventive effect by forming a resin layer such as an acrylic resin or an epoxy resin on the conductive layer instead of the above-mentioned metal, alloy, oxide or the like.

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

(Anti-blocking layer)
An anti-blocking layer 4 is provided on the surface of the polyester-based resin film 1 opposite to the easy-adhesion layer 2 side in order to prevent the films from blocking and to enable the roll-to-roll method. Good.

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

As the particles, those having transparency such as various metal oxides, glass and plastics can be used without particular limitation. For example, silica, alumina, titania, zirconia, inorganic particles such as calcium oxide, polymethylmethacrylate, polystyrene, polyurethane, acrylic resin, acrylic-styrene copolymer, benzoguanamine, melamine, crosslinked or not composed of various polymers such as polycarbonate. Examples include crosslinked organic particles and silicone particles. One kind or two or more kinds of particles can be appropriately selected and used.

The average particle diameter and blending amount of the above particles can be appropriately set in consideration of imparting surface irregularities and haze. The average particle diameter is preferably 0.5 μm to 2.0 μm, and the blending amount is preferably 0.2 to 5.0 parts by weight with respect to 100 parts by weight of the solid content of the resin composition.

The thickness of the conductive film of the present embodiment is preferably in the range of 2 to 200 μm, more preferably in the range of 10 to 100 μm, and more preferably in the range of 20 to 60 μm, like the resin film. Is more preferable. As a result, the conductive film itself can be made thin, and the thickness when used for an electromagnetic wave shield sheet, a sensor, etc. can be suppressed. Therefore, it is possible to reduce the thickness of the electromagnetic wave shield sheet and the sensor. Furthermore, when the thickness of the conductive film is within the above range, the mechanical strength can be sufficient while ensuring flexibility, and the film is rolled into an easily adhering layer or a conductive layer continuously. The forming operation becomes easy and the production efficiency is improved.

(Use of conductive film)
The conductive film of the present embodiment can be applied to various uses, and can be applied to, for example, an electromagnetic wave shield sheet, a surface 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 shielding sheet is preferably 20 μm to 300 μm.

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

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

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, "parts" means "parts by weight" unless otherwise specified.

<Example 1>
(Formation of easy adhesion layer)
A PET film is unwound from a roll of a polyethylene terephthalate film having a thickness of 100 μm (trade name “Lumirror #100-U40” manufactured by Toray Industries, Inc., hereinafter referred to as PET film), and an adhesive resin having ultraviolet curability on one side thereof. A composition ("Z-844-2L" manufactured by Aika Kogyo Co., Ltd.) was applied and dried at 80°C for 1 minute, and immediately thereafter, an ozone type high-pressure mercury lamp (15 cm condensing type, UV intensity 16 W/cm ² , integrated). Ultraviolet irradiation was performed with a light amount of 200 mJ/cm ² ) to form an easy-adhesion layer having a thickness of 1.5 μm. The surface temperature of the film-conveying roll at the time of UV irradiation was set to 50° C., and UV curing was performed while heating.

(Formation of conductive layer)
Next, a roll in which a long resin film having an easy-adhesion layer formed on a PET film was wound was placed in a sputtering device. Then, the resin film was fed at a film feed speed of 2 m/min, and in a 3.0×10 ⁻³ Torr atmosphere of 100 vol% Ar gas, using a Cu target material, by a sintered body DC magnetron sputtering method. A conductive layer (Cu layer) having a thickness of 200 nm was formed on the easy-adhesion layer, and finally the film was wound to prepare a wound body of the conductive film.

<Example 2>
A wound body of a conductive film was produced in the same manner as in Example 1 except that the surface temperature of the film transport roll at the time of ultraviolet irradiation was set to 75° C. and the ultraviolet curing was performed while heating.

<Example 3>
A wound body of a conductive film was produced in the same manner as in Example 1 except that the surface temperature of the film transport roll at the time of ultraviolet irradiation was 100° C. and the ultraviolet curing was performed while heating.

<Example 4>
A wound body of a conductive film was produced in the same manner as in Example 1 except that the surface temperature of the film transport roll at the time of ultraviolet irradiation was 125° C. and the ultraviolet curing was performed while heating.

<Comparative Example 1>
A wound body of a conductive film was produced in the same manner as in Example 1 except that the surface temperature of the film transport roll at the time of ultraviolet irradiation was set to 25° C. and the ultraviolet curing was performed at room temperature.

<Evaluation>
The following evaluations were performed on the produced easy adhesion layer and conductive film. The respective results are shown in Table 1.

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

(2) FT-IR measurement With respect to the easy-adhesion layer formed on the PET film, a reflection method (ATR method), wave number 500 cm ^{−1 to} 4000 cm, using an FT-IR measurement device (“Frontier” manufactured by Parkin Elmer). ^The infrared absorption spectrum was measured at ^-1 , resolution of 1.0 cm ^-1 , and integration times of 10 times. From the obtained spectrum, C = C-H read the absorbance _{Ab 1450} in absorbance _{Ab 1410,} and 1450 cm ^-1 due to C-H in due to 1410 cm ^-1, they from the absorbance ratio _(Ab 1410 / Ab ₁₄₅₀ ).

(3) Adhesion Evaluation The conductive film was cut out in a size of 10 mm×10 mm, and the thickness of the conductive layer (Cu layer) was increased to 2 μm by a plating method. Adhesion was evaluated by the cross-cut method based on JIS-K-5600 using a conductive film having a thick conductive layer as a measurement sample. Using a cutter knife or the like, make 11 cuts at 1 mm intervals on the conductive layer lengthwise and widthwise to make 100 squares in a grid pattern, and cut into about 75 mm length on the grid pattern. (Registered trademark) (manufactured by 3M, product name "610-1PK") is attached, then the end of the tape is grasped and peeled off in a direction of 60° for 0.5 to 1.0 second, and the conductive layer is peeled Was visually confirmed and evaluated. The case where there were 90 or more squares in which the conductive layer remained was evaluated as “◯”, and the case where there were less than 90 squares was evaluated as “x”.

(4) Wet tension measurement It was performed based on the regulation of JIS-K-6768. A Wak Pure Chemical wetting tension test mixture was used.

(Results and discussion)
In each of the conductive films of Examples, the adhesion of the conductive layer was good. On the other hand, in Comparative Example 1, many squares of the conductive layer were peeled off, and the adhesiveness was lowered. It is presumed that this is because the heating of the easy-adhesion layer during ultraviolet curing did not result in insufficient formation of the crosslinked structure in the easy-adhesion layer, resulting in a low film strength.

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

Claims (7)

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

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