JP2023081428A - Production method of conductive film for transfer and conductive film for transfer - Google Patents

Abstract

To provide a production method of a conductive film for transfer suitable for producing conductive films suitable for excellently transferring a conductive layer while suppressing generation of cracks in a cured resin layer being a primer layer of the conductive layer, as well as, to provide a conductive film for transfer obtained thereby.SOLUTION: A method for producing a conductive film for transfer X of the present invention includes: a first step of forming a resin layer 11 being a cured resin layer having a thickness of 3 μm or less on one side in a thickness direction of a temporary support film S; a second step of forming the conductive layer 12 on one side in the thickness direction of the resin layer 11 to obtain an intermediate laminate 10A; a third step of cutting the intermediate laminate 10A to obtain an intermediate laminate 10B; and a fourth step of forming a resin layer 13 on one side of the layer 12 in the thickness direction in the intermediate laminate 10B. Peel strength between the temporary support film S and the resin layer 11 after the fourth step is 1 N/24 mm or less.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method for producing a conductive film for transfer and a conductive film for transfer.

Conventionally, conductive films for transfer are known. The conductive film for transfer includes a temporary support film, a cured resin layer releasably in contact with the temporary support film, and a conductive layer in this order in the thickness direction. The conductive film for transfer is produced, for example, by a roll-to-roll method as follows. First, a cured resin layer is formed on a temporary support film as a substrate. The cured resin layer is a base layer for the conductive layer. Next, a conductive layer is formed on the cured resin layer by sputtering film formation of a transparent conductive material. Thereby, a roll-shaped conductive film for transfer is obtained. Next, the roll-shaped conductive film for transfer is cut to obtain a sheet-shaped conductive film for transfer (cutting step). The conductive layer is patterned as necessary.

Such a transfer conductive film is used as a supply material for a conductive layer in the process of manufacturing an optical article. For example, the conductive film for transfer is used as a supply material for a conductive layer patterned as a transparent electrode for a touch sensor in the manufacturing process of a foldable display panel. Specifically, it is as follows.

First, the conductive layer (patterned) side of the sheet-shaped conductive film for transfer is attached to a film-shaped polarizing plate (polarizing film) via an adhesive layer. Next, in the conductive film for transfer, the temporary support film is peeled off from the cured resin layer (peeling step). As a result, the cured resin layer and the conductive layer thereon are transferred to the polarizing film as a substrate-less transparent conductive film.

Thus, according to the conductive film for transfer, a substrate-less transparent conductive film can be attached to the polarizing film. Since the substrate-less transparent conductive film is thin and has excellent flexibility, it is suitable for ensuring good flexibility in foldable display panels. Therefore, the conductive film for transfer is suitable for manufacturing a thin foldable display panel. Techniques related to such a conductive film for transfer are described in Patent Document 1 below, for example.

JP 2019-31041 A

In the above-described cutting process for the conductive film for transfer, the thicker the cured resin layer of the transparent conductive film, the more likely cracks will occur in the cured resin layer. The occurrence of cracks in the cured resin layer is not preferable because it affects the electrical properties of the conductive layer on the cured resin layer. From the viewpoint of suppressing cracks, it is preferable that the cured resin layer is thin. On the other hand, in the above-described peeling process for the conductive film for transfer, the thinner the cured resin layer of the substrate-less transparent conductive film is, the thinner the film is, the more difficult it is to peel off the temporary support film from the cured resin layer of the same film. It tends to require more force. This is because the thinner the cured resin layer is, the less stress is concentrated on the interface between the cured resin layer and the temporary support film at the time of peeling, and the smaller the force effectively acting on the interface. If the peeling force is too large, the substrate-less transparent conductive film is not properly transferred to the optical article in the peeling step. From the viewpoint of transferability, the thicker the cured resin layer, the better. As described above, in the conductive film for transfer, conventionally, there is a trade-off relationship between the thickness of the cured resin layer required from the viewpoint of crack suppression and the thickness of the cured resin layer required from the viewpoint of transferability.

The present invention provides a method for producing a conductive film for transfer, which is suitable for producing a conductive film for transfer, which is suitable for good transfer of a conductive layer, while suppressing the occurrence of cracks in a cured resin layer, and , to provide a conductive film for transfer obtained thereby.

The present invention [1] is a first resin layer on one side in the thickness direction of a temporary support film as a cured resin layer in releasable contact with the temporary support film and having a thickness of 3 μm or less. a first step of forming a first resin layer; a second step of forming a conductive layer on one side in the thickness direction of the first resin layer to obtain a first intermediate laminate; a third step of cutting to obtain a second intermediate laminate; and a fourth step of forming a second resin layer on one side in the thickness direction of the conductive layer in the second intermediate laminate, It includes a method for producing a conductive film for transfer, wherein the peel strength between the temporary support film and the first resin layer after the process is 1 N/24 mm or less.

The present invention [2] includes the method for producing a conductive film for transfer according to [1] above, wherein the total thickness of the thickness of the first resin layer and the thickness of the second resin layer exceeds 2 μm.

The present invention [3] includes the method for producing a conductive film for transfer according to the above [1] or [2], wherein the second resin layer has a thickness of 2 μm or more.

The present invention [4] comprises a temporary support film, a first resin layer as a cured resin layer in releasable contact with the temporary support film, a conductive layer, and a second resin layer in the thickness direction. A conductive film for transfer, provided in this order, wherein the first resin layer has a thickness of 3 μm or less, and a peel strength between the temporary support film and the first resin layer is 1 N/24 mm or less. including.

The present invention [5] includes the conductive film for transfer according to [4] above, wherein the total thickness of the thickness of the first resin layer and the thickness of the second resin layer exceeds 2 μm.

The present invention [6] includes the conductive film for transfer according to the above [4] or [5], wherein the second resin layer has a thickness of 2 μm or more.

The present invention [7] provides the above [4] to [6], wherein the surface of the first resin layer on the conductive layer side has an elastic modulus at 25° C. measured by a nanoindentation method of 4 GPa or more. The conductive film for transfer according to any one of.

The present invention [8] includes the conductive film for transfer according to any one of [4] to [7] above, wherein the conductive layer contains an indium-containing conductive oxide.

In the manufacturing method of the conductive film for transfer of the present invention, as described above, the first resin layer (cured resin layer) of the first intermediate laminate cut in the third step has a thickness of 3 μm or less. Such a configuration is suitable for suppressing the occurrence of cracks in the third step (cutting step) in the first resin layer. In addition, as described above, the method for producing a conductive film for transfer of the present invention includes a fourth step of forming a second resin layer on one side in the thickness direction of the conductive layer after the third step. The peel strength between the subsequent temporary support film and the first resin layer is 1 N/24 mm or less. In such a configuration, after the second resin layer side of the conductive film for transfer manufactured by this manufacturing method is attached to the optical component, the peeling force required to peel the temporary support film from the first resin layer is suitable for reducing The method for producing a conductive film for transfer as described above suppresses the occurrence of cracks in the first resin layer as a base layer of the conductive layer, and the conductive film for transfer suitable for excellently transferring the conductive layer. suitable for manufacturing

The conductive film for transfer of the present invention is suitable for suppressing the occurrence of cracks in the first resin layer and for transferring the conductive layer satisfactorily.

BRIEF DESCRIPTION OF THE DRAWINGS It is process drawing of one Embodiment of the manufacturing method of the conductive film for transfer of this invention. 1A shows a step of preparing a temporary support film, FIG. 1B shows a step of forming a first resin layer, and FIG. 1C shows a step of forming a conductive layer to obtain a first intermediate laminate. Represents a step subsequent to the step shown in FIG. 1C. FIG. 2A shows the step of cutting the first intermediate laminate to obtain the second intermediate laminate, and FIG. 2B shows the step of forming the second resin layer on the conductive layer. The patterning process when the manufacturing method of the conductive film for transfer includes the patterning process of the conductive layer is shown. It is a cross-sectional schematic diagram of the conductive film for transfer manufactured when the manufacturing method of the conductive film for transfer includes the patterning process of a conductive layer. An example of how to use the conductive film for transfer is shown. FIG. 5A shows the step of attaching the conductive film for transfer to the optical component, and FIG. 5B shows the step of peeling off the temporary support film.

1A to 2B are process diagrams of one embodiment of the method for producing a conductive film for transfer of the present invention. In the present embodiment, the method for producing a conductive film for transfer includes a preparation step (FIG. 1A), a first resin layer forming step (FIG. 1B), a conductive layer forming step (FIG. 1C), and a cutting step (FIG. 2A ) and a second resin layer forming step (FIG. 2B). Specifically, it is as follows.

First, in the preparation step, a temporary support film S is prepared as shown in FIG. 1A. The temporary support film S has a first surface Sa and a second surface Sb opposite to the first surface Sa. The temporary support film S has a thickness between the first surface Sa and the second surface Sb. The temporary support film S has a sheet shape extending in a direction perpendicular to the thickness direction H (plane direction). Moreover, the temporary support film S has a long shape so that this manufacturing method can be implemented by a roll-to-roll system.

The temporary support film S is, for example, a flexible resin film. Examples of materials for the temporary support film S include polyester resins, polyolefin resins, acrylic resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, and polystyrene resins. . Polyester resins include, for example, polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Polyolefin resins include, for example, polyethylene, polypropylene, and cycloolefin polymers (COP). Examples of acrylic resins include polymethacrylate. From the viewpoint of the balance between flexibility and strength, the material of the temporary support film S is preferably at least one selected from the group consisting of polyester resins and polyolefin resins, more preferably PET and COP. At least one selected from the group consisting of is used.

The water contact angle (pure water contact angle) of the first surface Sa of the temporary support film S is preferably 70° or more, more preferably 75° or more, and still more preferably 80° or more. Such a configuration is preferable for ensuring peelability when peeling the temporary support film S from the resin layer 11 described later. The water contact angle of the first surface Sa is preferably 130° or less, more preferably 120° or less, and even more preferably 110° or less. Such a configuration is preferable for ensuring the adhesiveness of the temporary support film S to the resin layer 11 until the temporary support film S is released from the resin layer 11 described later. A water contact angle can be measured as follows. First, about 1 μL of pure water is dropped onto the first surface Sa of the temporary support film S to form water droplets. Next, the angle formed by the surface of the water droplet on the first surface Sa and the first surface Sa is measured. For the measurement, for example, a contact angle meter (product name “DMo-501”, manufactured by Kyowa Interface Science Co., Ltd.) can be used.

The first surface Sa of the temporary support film S may be surface-modified. By the surface modification treatment of the first surface Sa, the water contact angle of the first surface Sa can be adjusted, and the peel strength between the temporary support film S and the resin layer 11 can be adjusted. Surface modification treatments include, for example, stripping treatments, plasma treatments, corona treatments, and ozone treatments. The first surface Sa is preferably subjected to surface modification treatment by at least one selected from the group consisting of peeling treatment, plasma treatment, corona treatment, and ozone treatment. Release agents for release treatment include, for example, silicone resin-containing release agents, long-chain alkyl resin-containing release agents, and fatty acid amide resin-containing release agents. When plasma processing is performed on the first surface Sa, the processing is, for example, atmospheric pressure plasma processing. Also, the discharge power in the plasma treatment is, for example, 10 W or more and, for example, 10000 W or less.

The thickness of the temporary support film S is preferably 3 μm or more, more preferably 10 μm or more, still more preferably 30 μm or more. The thickness of the temporary support film S is preferably 300 μm or less, more preferably 200 μm or less, still more preferably 100 μm or less. These configurations regarding the thickness of the temporary support film S are preferable for ensuring the handleability of the conductive film X for transfer to be produced.

Next, in the first resin layer forming step, as shown in FIG. 1B, on the first surface Sa as one surface in the thickness direction H of the long temporary support film S, a resin as a transparent cured resin layer A layer 11 (first resin layer) is formed (this step corresponds to the first step in the present invention). Thereby, the temporary support film S with the resin layer 11 is obtained. This step is implemented by a roll-to-roll method. Examples of the resin layer 11 include a hard coat layer and a refractive index adjustment layer. The resin layer 11 may be a multifunctional layer that serves both as a hard coat layer and a refractive index adjusting layer.

The resin layer 11 is formed, for example, by applying a first curable resin composition (varnish) on the first surface Sa of the temporary support film S to form a coating film, and then drying and curing the coating film. can. The first curable resin composition contains a curable resin and a solvent. The resin layer 11 is a cured product of a first curable resin composition (specifically, a curable resin).

Examples of curable resins include polyester resins, acrylic resins, urethane resins, acrylic urethane resins, amide resins, silicone resins, epoxy resins, and melamine resins. These curable resins may be used alone, or two or more of them may be used in combination. From the viewpoint of ensuring the light transmittance and hardness of the resin layer 11, acrylic resin is preferably used as the curable resin.

Examples of curable resins include ultraviolet curable resins and thermosetting resins. When the first curable resin composition contains an ultraviolet-curable resin, the coating film is cured by ultraviolet irradiation. When the first curable resin composition contains a thermosetting resin, the coating film is cured by heating. As the curable resin, an ultraviolet curable resin is preferably used from the viewpoint of improving the production efficiency of the conductive film X for transfer since it can be cured without heating to a high temperature. The UV-curable resin includes at least one selected from the group consisting of UV-curable monomers, UV-curable oligomers, and UV-curable polymers. Specific examples of the composition containing an ultraviolet curable resin include the composition for forming a hard coat layer described in JP-A-2016-179686.

Solvents contained in the first curable resin composition include, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, toluene, xylene, methanol, ethanol, isopropanol, ethylene glycol monomethyl ether acetate, propylene glycol. monomethyl ether acetate, dichloromethane, and chloroform.

The first curable resin composition may contain fine particles. The addition of fine particles to the first curable resin composition is useful for adjusting the hardness of the resin layer 11, adjusting the surface roughness, adjusting the refractive index, and imparting antiglare properties. Microparticles include, for example, inorganic particles and organic particles. Inorganic particles include, for example, metal oxide particles and glass particles. Materials for metal oxide particles include, for example, silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Materials for the organic particles include, for example, polymethylmethacrylate, polystyrene, polyurethane, acrylic-styrene copolymers, benzoguanamine, melamine, and polycarbonate.

The thickness T1 of the resin layer 11 is 3 μm or less, preferably 2.5 μm or less, more preferably 2 μm or less, still more preferably 1.7 μm or less, and particularly preferably 1.5 μm or less. Such a configuration is suitable for suppressing the occurrence of cracks in the resin layer 11 in the later-described cutting step (FIG. 2A). In addition, from the viewpoint of ensuring the releasability of the resin layer 11 from the temporary support film S, the thickness T1 is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 0.8 μm or more, and particularly preferably is 1 μm or more.

The elastic modulus of the surface 11a of the resin layer 11 at 25° C. measured by a nanoindentation method is preferably 4 GPa or higher, more preferably 7 GPa or higher, even more preferably 9 GPa or higher, and particularly preferably 10 GPa or higher. Such a configuration is preferable from the viewpoint of suppressing undulations in the resin layer 11 after the peeling process described later. The elastic modulus of the surface 11a of the resin layer 11 at 25° C. measured by a nanoindentation method is preferably 20 GPa or less, more preferably 17 GPa or less, and even more preferably 15 GPa or less. Such a configuration is preferable for ensuring the flexibility of the resin layer 11, and therefore preferable for ensuring the handleability of the conductive film X for transfer. The elastic modulus includes the elastic modulus of the surface 11a of the resin layer 11 before the formation of the conductive layer 12 in the manufacturing process of the conductive film X for transfer, and the surface 11a of the resin layer 11 in the manufactured conductive film X for transfer. is included. Methods for adjusting the elastic modulus of the surface 11a of the resin layer 11 include, for example, adjusting the blending amount of inorganic particles in the resin layer 11 and adjusting curing conditions. As a method for adjusting the elastic modulus of the surface 11a of the resin layer 11, it is also possible to mix two or more different curable resins in the first curable resin composition and adjust the mixing ratio.

The nanoindentation method is a technique for measuring various physical properties of samples on a nanometer scale. In this embodiment, the nanoindentation method is performed in compliance with ISO14577. In the nanoindentation method, a process of pushing an indenter into a sample set on a stage (loading process) and then a process of withdrawing the indenter from the sample (unloading process) are performed. The load acting between the indenter and the sample and the relative displacement of the indenter with respect to the sample are measured (load-displacement measurement). This makes it possible to obtain a load-displacement curve. From this load-displacement curve, it is possible to obtain the physical properties of the measurement sample, such as elastic modulus and hardness, based on nanometer-scale measurements. For the load-displacement measurement of the surface of the resin layer 11 by the nanoindentation method, for example, a nanoindenter (trade name “Triboindenter”, manufactured by Hysitron) can be used. In the measurement, the measurement mode was single indentation measurement, the measurement temperature was 25°C, the indenter used was a Berkovich (triangular pyramid) type diamond indenter, and the maximum indentation depth (maximum The displacement H1) is 50 nm, the pressing speed of the indenter is 5 nm/sec, and the withdrawal speed of the indenter from the measurement sample during the unloading process is 5 nm/sec. Based on the load-displacement curve obtained by this measurement, for example, the maximum load Pmax (the load acting on the indenter at the maximum displacement H1), the projected contact area Ap (the projection of the contact area between the indenter and the sample at the maximum load area), contact stiffness S (the slope of the tangent to the load-displacement curve (unloading curve) at the start of the unloading process), and the amount of plastic deformation H2 on the sample surface after the unloading process (when the indenter is separated from the sample surface The depth of the recess that is subsequently maintained in the sample surface) can be obtained. Then, the elastic modulus (=π ^1/2 S/2Ap ^1/2 ) of the sample surface can be calculated from the contact stiffness S and the contact projected area Ap.

A surface 11a (a surface on which a conductive layer 12 described later is laminated) as one surface in the thickness direction H of the resin layer 11 is subjected to a surface modification treatment as necessary. Surface modification treatments include, for example, plasma treatment, corona treatment, and ozone treatment. From the viewpoint of ensuring high adhesion between the resin layer 11 and the conductive layer 12, the surface 11a is preferably plasma-treated. When plasma-processing the surface 11a, argon gas, for example, is used as an inert gas in the plasma processing. Also, the discharge power in the plasma treatment is, for example, 10 W or more and, for example, 10000 W or less.

Next, in the conductive layer forming step, as shown in FIG. 1C, a conductive layer 12 is formed on the resin layer 11 (this step corresponds to the second step in the present invention). Specifically, the material is deposited on the resin layer 11 of the temporary support film S with the resin layer 11 by sputtering to form the conductive layer 12 . Thereby, the intermediate laminate 10A (first intermediate laminate) is obtained. The conductive layer 12 has both optical transparency and electrical conductivity in this embodiment. The conductive layer 12 is formed as an amorphous film, for example. By heating the amorphous conductive layer 12 at a predetermined timing, it can be converted to a crystalline conductive layer 12 .

In the sputtering method of this step, for example, a sputtering film forming apparatus capable of carrying out a film forming process by a roll-to-roll method is used. Specifically, in the sputtering method, while a sputtering gas (inert gas) is introduced under vacuum conditions into a film forming chamber provided in a sputtering film forming apparatus, a negative voltage is applied to a target placed on a cathode in the film forming chamber. is applied. As a result, glow discharge is generated to ionize the gas atoms, the gas ions collide with the target surface at high speed, the target material is ejected from the target surface, and the ejected target material is applied to the temporary support film S with the resin layer 11. It is deposited on the resin layer 11 .

Examples of the material of the target placed on the cathode in the deposition chamber (that is, the material of the conductive layer 12) include metals and conductive oxides. Metals include, for example, copper, silver, and alloys thereof. As the conductive oxide, for example, at least one metal selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W Alternatively, metal oxides containing metalloids may be mentioned. Specifically, conductive oxides include indium-containing conductive oxides and antimony-containing conductive oxides. Indium-containing conductive oxides include, for example, indium tin composite oxide (ITO), indium zinc composite oxide (IZO), indium gallium composite oxide (IGO), and indium gallium zinc composite oxide (IGZO). be done. Antimony-containing conductive oxides include, for example, antimony-tin composite oxide (ATO). From the viewpoint of achieving high light transmittance and good conductivity in the conductive layer 12, the conductive oxide is preferably an indium-containing conductive oxide, more preferably containing both In and Sn. Indium tin composite oxide (ITO) is used. This ITO may contain metals or metalloids other than In and Sn in amounts less than the respective contents of In and Sn.

When ITO is used as the conductive oxide, the ratio of the tin oxide content to the total content of indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) in the conductive layer 12 is preferably 1% by mass or more. , more preferably 2% by mass or more, still more preferably 3% by mass or more, and particularly preferably 5% by mass or more. Such a configuration is suitable for ensuring durability of the conductive layer 12 . In addition, from the viewpoint of forming the conductive layer 12 that is easily crystallized by heating in this step, the above-mentioned proportion of the tin oxide content is preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 12% by mass or less. is. The content of tin oxide can be adjusted by adjusting the tin oxide concentration in the ITO target used in the sputtering method.

As the sputtering gas, rare gas atoms are used in this embodiment. Noble gas atoms include Ar, Kr and Xe, preferably Kr and/or Ar are used.

The sputtering method is preferably a reactive sputtering method. In the reactive sputtering method, oxygen as a reactive gas is introduced into the deposition chamber in addition to the sputtering gas. In the reactive sputtering method, the ratio of the introduction amount of oxygen to the total introduction amount of the sputtering gas and oxygen introduced into the deposition chamber is, for example, 0.01 flow % or more and, for example, 15 flow % or less.

The atmospheric pressure in the film formation chamber during film formation by the sputtering method (sputter film formation) is, for example, 0.02 Pa or higher and, for example, 1 Pa or lower.

The temperature of the work film during sputtering film formation is, for example, 100° C. or less. In order to suppress outgassing from the work film and thermal expansion of the work film during sputtering deposition, it is preferable to cool the work film. Suppression of outgassing and suppression of thermal expansion help achieve high crystal stability in the conductive layer 12 . From this point of view, the temperature of the work film during sputtering film formation is preferably 20° C. or less, more preferably 10° C. or less, even more preferably 5° C. or less, particularly preferably 0° C. or less. It is 50°C or higher, preferably -20°C or higher, more preferably -10°C or higher, and still more preferably -7°C or higher.

Power supplies for applying voltage to the target include, for example, DC power supplies, AC power supplies, MF power supplies, and RF power supplies. As a power supply, a DC power supply and an RF power supply may be used together. The absolute value of the discharge voltage during sputtering film formation is, for example, 50 V or higher and, for example, 500 V or lower.

In this manufacturing method, next, as shown in FIG. 2A, the long intermediate laminate 10A is cut to obtain a sheet-shaped intermediate laminate 10B (second intermediate laminate) (this step is the corresponds to the third step in). In this step, the intermediate laminate 10A is cut into a predetermined size and shape. For cutting, for example, a roll-to-sheet type sizing cutter can be used.

Next, in the second resin layer forming step, as shown in FIG. 2B, a resin layer 13 (second resin layer) is formed on one surface of the conductive layer 12 in the thickness direction H of the intermediate laminate 10B (this The step corresponds to the fourth step in the present invention). Examples of the resin layer 13 include a transparent cured resin layer and a transparent adhesive layer.

When the resin layer 13 is a cured resin layer, for example, the resin layer 13 is formed by applying a second curable resin composition (varnish) on the conductive layer 12 to form a coating film, and then drying the coating film. and hardening. The second curable resin composition contains a curable resin and a solvent. The curable resin includes, for example, the curable resins described above with respect to the first curable resin composition. From the viewpoint of ensuring the light transmittance and hardness of the resin layer 13, an acrylic resin is preferably used as the curable resin. In addition, ultraviolet curable resin is preferably used as the curable resin from the viewpoint of improving the production efficiency of the conductive film X for transfer since it can be cured without heating to a high temperature. Examples of the solvent contained in the second curable resin composition include the solvents described above for the first curable resin composition.

When the resin layer 13 is a transparent adhesive layer, the resin layer 13 is a pressure-sensitive adhesive layer formed from an adhesive composition. The resin layer 13 can be formed, for example, by applying an adhesive composition (varnish) on the conductive layer 12 to form a coating film, and then drying the coating film. The resin layer 13 contains at least a base polymer. The base polymer is an adhesive component that develops adhesiveness in the resin layer 13 . Base polymers include, for example, acrylic polymers, silicone polymers, polyester polymers, polyurethane polymers, polyamide polymers, polyvinyl ether polymers, vinyl acetate/vinyl chloride copolymers, modified polyolefin polymers, epoxy polymers, fluoropolymers, and rubber polymers. The base polymer may be used alone or in combination of two or more. From the viewpoint of ensuring good transparency and adhesiveness in the resin layer 13, acrylic polymer is preferably used as the base polymer. Moreover, the resin layer 13 as an adhesive layer may contain a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, and a silane coupling agent.

The thickness T2 of the resin layer 13 is preferably 2 μm or more, more preferably 2.5 μm or more, still more preferably 3 μm or more, from the viewpoint of ensuring peelability when the temporary support film S is peeled from the resin layer 11. It is preferably 3.5 μm or more. From the viewpoint of ensuring the flexibility of the conductive film X for transfer, the thickness T2 is preferably 5 μm or less, more preferably 4.5 μm or less, and even more preferably 4 μm or less.

Thickness T2 of resin layer 13 is preferably greater than thickness T1 of resin layer 11 . The ratio of the thickness T2 to the thickness T1 (T2/T1) is preferably greater than 1, more preferably 2 or greater, even more preferably 3 or greater, and particularly preferably 4 or greater. The ratio (T2/T1) is, for example, 10 or less.

One surface (upper surface in the drawing) of the resin layer 13 in the thickness direction H may be subjected to a surface modification treatment. Surface modification treatments include, for example, plasma treatment, corona treatment, and ozone treatment.

As described above, the conductive film X for transfer can be manufactured. The conductive film X for transfer includes a temporary support film S and a transparent conductive film Y. As shown in FIG. The transparent conductive film Y is a substrate-less transparent conductive film temporarily supported by a temporary support film S. As shown in FIG. The transparent conductive film Y includes a resin layer 11, a conductive layer 12, and a resin layer 13 in order in the thickness direction H. As shown in FIG. That is, the transfer conductive film X includes a temporary support film S, a resin layer 11, a conductive layer 12, and a resin layer 13 in the thickness direction H in this order.

In the transfer conductive film X, the peel strength F1 between the temporary support film S and the resin layer 11 after the second resin layer forming step (fourth step) is 1 N/24 mm or less, preferably 0.7 N. /24 mm or less, more preferably 0.5 N/24 mm or less, still more preferably 0.3 N/24 mm or less, and particularly preferably 0.2 N/24 mm or less. The peel strength F1 can be measured by the method described below with respect to the examples.

The peel strength F1 is smaller than the peel strength F2 between the temporary support film S and the resin layer 11 in the intermediate laminates 10A and 10B before the second resin layer forming step (fourth step). The peel strength F2 is, for example, 0.2 N/24 mm or more, preferably 0.5 N/24 mm or more, more preferably 0.8 N/24 mm or more, still more preferably 1 N/24 mm or more. The peel strength F2 can be measured by the method described below with respect to the examples. Also, the difference (F2-F1) between the peel strength F1 and the peel strength F2 is, for example, 0.2 N/24 mm or more, preferably 0.6 N/24 mm or more, more preferably 0.8 N/24 mm or more. The ratio (F1/F2) of the peel strength F1 to the peel strength F2 is, for example, 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less, and still more preferably 0.2 or less. The ratio (F1/F2) is, for example, 0.01 or more. These numerical values regarding the peel strengths F1 and F2 are numerical values regardless of whether the conductive layer 12 is amorphous or crystalline.

In the transfer conductive film X, the total thickness (T1+T2) of the thickness T1 of the resin layer 11 and the thickness of the resin layer T2 is preferably greater than 2 μm, more preferably 3 μm or more, still more preferably 4 μm or more, especially It is preferably 5 μm or more. Such a configuration is preferable for ensuring peelability when peeling the temporary support film S from the resin layer 11 .

This manufacturing method may include a step of patterning the conductive layer 12 after the conductive layer forming step (FIG. 1C) and before the second resin layer forming step (FIG. 2B). FIG. 3 exemplarily shows the step of patterning the conductive layer 12 after the conductive layer forming step (FIG. 1C) and before the cutting step (FIG. 2A). By etching the conductive layer 12 through a predetermined etching mask, the conductive layer 12 can be patterned. A transparent electrode and a transparent wiring can be formed in the conductive layer 12 by the patterning. When the conductive layer 12 is patterned, in the second resin layer forming step, as shown in FIG. 13 (second resin layer) is formed.

The conductive film X for transfer is used in the manufacturing process of an optical article, for example, as follows (FIGS. 5A and 5B show an example of how to use the conductive film X for transfer).

First, as shown in FIG. 5A, the resin layer 13 side of the conductive film X for transfer is bonded to the optical component M (bonding step). Optical component M is an element of an optical article. Examples of the optical component M include a film-like polarizing plate (polarizing film) and an electrochromic light control film. When the resin layer 13 is a cured resin layer, in this step, the resin layer 13 side of the transfer conductive film X is attached to the optical component M via an adhesive (not shown). When the resin layer 13 is an adhesive layer, in this step, the transfer conductive film X is attached to the optical component M by the adhesive force of the resin layer 13 .

Next, as shown in FIG. 5B, while leaving the substrate-less transparent conductive film Y (the resin layer 11 and the conductive layer 12) on the optical component S, the resin layer 11 of the transparent conductive film Y is separated from the temporary support film. S is peeled off (peeling step). Thereby, the conductive layer 12 is transferred to the optical component M together with the resin layer 11 .

In the manufacturing process of an optical article, the transfer conductive film X is used, for example, as described above.

In the method of manufacturing the conductive film for transfer described above, the thickness T1 of the resin layer 11 (cured resin layer) of the intermediate laminate 10A cut in the cutting step (FIG. 2A) is 3 μm or less, preferably 2.0 μm. It is 5 µm or less, more preferably 2 µm or less, even more preferably 1.7 µm or less, and particularly preferably 1.5 µm or less. The configuration in which the thickness of the resin layer 11 as the cured resin layer is suppressed to this extent is suitable for suppressing the occurrence of cracks in the resin layer 11 in the cutting process.

The above-described method for producing a conductive film for transfer includes a step (FIG. 2B) of forming a resin layer 13 on one side of the conductive layer 12 in the thickness direction H after the cutting step (FIG. 2A). The peel strength between the support film S and the resin layer 11 is 1 N/24 mm or less, preferably 0.7 N/24 mm or less, more preferably 0.5 N/24 mm or less, still more preferably 0.3 N/24 mm or less. , particularly preferably 0.2 N/24 mm or less. Such a configuration is suitable for reducing the peeling force required to peel the temporary support film S from the resin layer 11 after the resin layer 13 side of the transfer conductive film X is attached to the optical component M.

As described above, the present manufacturing method manufactures a transfer conductive film X suitable for excellent transfer of the conductive layer 12 while suppressing the occurrence of cracks in the resin layer 11 as the base layer of the conductive layer 12. suitable for

EXAMPLES The present invention will be specifically described below with reference to Examples. However, the invention is not limited to the examples. In addition, the specific numerical values such as the compounding amount (content), physical property values, parameters, etc. described below are the corresponding compounding amounts ( content), physical property values, parameters, etc., upper limits (values defined as “less than” or “less than”) or lower limits (values defined as “greater than” or “greater than”).

[Example 1]
<Preparation of temporary support film>
First, a long polyethylene terephthalate (PET) film (product name “Pana-Peel TP-01”, thickness 50 μm, manufactured by Panac Co., Ltd.) whose surface was subjected to release treatment was prepared. Next, one side (first side) of the PET film was plasma-treated under predetermined conditions using a roll-to-roll type plasma treatment apparatus. In this plasma treatment, the discharge power was adjusted to change the water contact angle (°) on the surface of the temporary support to the value shown in Table 1. A temporary support film was produced as described above.

<Formation of first resin layer>
Next, a first resin layer was formed on the temporary support film (first resin layer forming step). Specifically, first, the first surface of the temporary support film was coated with the resin composition C1 as the first curable resin composition using a gravure coater to form a coating film. The resin composition C1 comprises 100 parts by mass of the first UV-curable resin composition (product name “TYZ72-A12”, manufactured by Toyochem) and 3 parts by mass of a leveling agent (product name “Grandic PC4100”, manufactured by DIC). is a mixture of Next, the coating film on the temporary support film was dried by heating and then cured by UV irradiation. The heating temperature was 80° C. and the heating time was 60 seconds. In the ultraviolet irradiation, a high-pressure mercury lamp was used as a light source, ultraviolet rays with a wavelength of 365 nm were used, and the integrated irradiation light amount was 230 mJ/cm ² . As described above, a first resin layer having a thickness of 1 μm was formed on the temporary support film.

<Formation of conductive layer>
Next, a conductive layer was formed on the first resin layer (conductive layer forming step). Specifically, an amorphous transparent conductive layer having a thickness of 50 nm was formed on the first resin layer of the temporary support film with the first resin layer by a reactive sputtering method. Thus, a long first intermediate laminate was obtained. The first intermediate laminate includes a temporary support film, a first resin layer, and a conductive layer in order in the thickness direction.

In the reactive sputtering method, a roll-to-roll type sputtering deposition apparatus (winding-type DC magnetron sputtering apparatus) was used. The sputtering film forming apparatus includes a film forming chamber in which the film forming process can be performed while the work film (temporary support film with the first resin layer) is run in a roll-to-roll manner. The running speed of the work film in the apparatus was set to 4.0 m/min, and the running tension (tension per unit length in the width direction of the film) acting on the work film in the running direction was set to 200 to 500 N/m. The conditions for sputtering film formation are as follows.

A sintered body of indium oxide and tin oxide (with a tin oxide concentration of 10% by mass) was used as a target. A DC power source was used as a power source for applying voltage to the target, and the output of the DC power source was 24.2 kW. The horizontal magnetic field strength on the target was set to 90 mT. The film formation temperature (the temperature of the work film on which the conductive layer is laminated) was -5°C. After the film formation chamber was evacuated until the partial pressure of water in the film formation chamber reached 5×10 ⁻⁴ Pa, Ar as a sputtering gas and oxygen as a reactive gas were introduced into the film formation chamber. Then, the atmospheric pressure in the film forming chamber was set to 0.4 Pa. The ratio of the amount of oxygen introduced to the total amount of Ar and oxygen introduced into the film formation chamber was about 2% by flow rate, and was adjusted so that the surface resistance value of the formed ITO film was 130Ω/□.

<Cutting>
Next, the long first intermediate laminate was cut to obtain a sheet-shaped second intermediate laminate. A shirring type roll-to-sheet cutting machine was used for cutting.

<Formation of second resin layer>
Next, a second resin layer was formed on the conductive layer (second resin layer forming step). Specifically, first, a second curable resin composition (product name “Z-773-2L”, manufactured by Aica Co., Ltd.) was applied on the conductive layer using a gravure coater to form a coating film. Next, this coating film was dried by heating and then cured by UV irradiation. The heating temperature was 80° C. and the heating time was 60 seconds. In the ultraviolet irradiation, a high-pressure mercury lamp was used as a light source, ultraviolet rays with a wavelength of 365 nm were used, and the cumulative irradiation light amount was 300 mJ/cm ² . As described above, a second resin layer having a thickness of 2 μm was formed on the conductive layer.

As described above, the conductive film for transfer of Example 1 was produced. The conductive film for transfer of Example 1 includes a temporary support film, a first resin layer (thickness of 1 μm), a conductive layer (thickness of 50 nm), and a second resin layer (thickness of 2 μm) in the thickness direction. prepare in order.

[Example 2]
A conductive film for transfer of Example 2 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. In the second resin layer forming step, a second resin layer having a thickness of 4 μm was formed.

[Example 3]
A conductive film for transfer of Example 3 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. In the first resin layer forming step, a first resin layer having a thickness of 3 μm was formed.

[Example 4]
A conductive film for transfer of Example 4 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. In the step of forming the first resin layer, the resin composition C2 was used as the first curable resin composition, and the cumulative irradiation light amount was set to 250 mJ/cm ² . Resin composition C2 comprises 80 parts by mass of a second UV curable resin composition (product name “Unidic ELS888”, manufactured by DIC) and a third UV curable resin composition (product name “Unidic RS28-605”, DIC manufactured by BASF) and 4 parts by weight of a photopolymerization initiator (product name “Irgacure 184” manufactured by BASF). Also, in the second resin layer forming step, a second resin layer having a thickness of 4 μm was formed.

[Example 5]
A conductive film for transfer of Example 5 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. In the step of forming the first resin layer, the resin composition C3 was used as the first curable resin composition, and the cumulative irradiation light amount was set to 250 mJ/cm ² . Resin composition C3 comprises 20 parts by mass of a second UV curable resin composition (product name “Unidic ELS888”, manufactured by DIC) and a third UV curable resin composition (product name “Unidic RS28-605”, DIC Co., Ltd.) is a mixture with 80 parts by mass. Also, in the second resin layer forming step, a second resin layer having a thickness of 4 μm was formed.

[Example 6]
A conductive film for transfer of Example 6 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. In the first resin layer forming step, resin composition C4 was used as the first curable resin composition. Resin composition C4 comprises 100 parts by mass of the fourth ultraviolet curable resin composition (product name “Luxidia V-6000”, manufactured by DIC) and 3 parts by mass of a photopolymerization initiator (product name “Irgacure 184”, manufactured by BASF). It is a mixture of Also, in the second resin layer forming step, a second resin layer having a thickness of 4 μm was formed.

[Example 7]
A conductive film for transfer of Example 7 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. The temporary support film was not plasma treated. In the second resin layer forming step, a second resin layer having a thickness of 4 μm was formed.

[Example 8]
A conductive film for transfer of Example 8 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. The temporary support film was not plasma treated. In the first resin layer forming step, a first resin layer having a thickness of 3 μm was formed.

[Example 9]
A conductive film for transfer of Example 9 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. The temporary support film was not plasma treated. In the second resin layer forming step, a second resin layer having a thickness of 1 μm was formed.

[Comparative Example 1]
A conductive film for transfer of Comparative Example 1 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. The temporary support film was not plasma treated. In the first resin layer forming step, a first resin layer having a thickness of 4 μm was formed. In the second resin layer forming step, a second resin layer having a thickness of 1 μm was formed.

[Comparative Example 2]
A conductive film for transfer of Comparative Example 2 was produced in the same manner as the conductive film for transfer of Example 1 except for the following. The temporary support film was not plasma treated. In the first resin layer forming step, a first resin layer having a thickness of 4 μm was formed. The second resin layer forming step was not performed (that is, the second resin layer was not formed).

<Water contact angle>
The water contact angle was examined for the first surface of the temporary support film in each conductive film for transfer of Examples 1 to 9 and Comparative Examples 1 and 2. Specifically, first, water droplets were formed by dropping about 1 μL of pure water on the first surface of the temporary support film obtained in the production process of the conductive film for transfer. Next, the angle formed by the surface of the water droplet on the first surface and the first surface was measured. A contact angle meter (product name: "DMo-501", manufactured by Kyowa Interface Science Co., Ltd.) was used for the measurement. Tables 1 and 2 show the measurement results.

<Elastic modulus of the first resin layer>
The surface of the first resin layer (the surface on the side of the conductive layer) in each conductive film for transfer of Examples 1 to 9 and Comparative Examples 1 and 2 was subjected to load-displacement measurement by a nanoindentation method. Specifically, first, a measurement sample (5 mm×5 mm) was cut out from the temporary support film with the first resin layer obtained in the production process of the conductive film for transfer. Next, using a nanoindenter (trade name “Triboindenter”, manufactured by Hysitron), the load-displacement measurement of the surface of the first resin layer in the measurement sample was performed in accordance with ISO 14577 to obtain a load-displacement curve. . In this measurement, the measurement mode is single indentation measurement, the measurement temperature is 25°C, the indenter used is a Berkovich (triangular pyramid) type diamond indenter, and the maximum indentation depth (maximum The displacement H1) was 50 nm, the pressing speed of the indenter was 5 nm/sec, and the withdrawal speed of the indenter from the measurement sample during the unloading process was 5 nm/sec. Based on the obtained load-displacement curve, maximum load Pmax (load acting on the indenter at maximum displacement H1), projected contact area Ap (projected area of contact area between indenter and sample at maximum load), contact The stiffness S (slope of the tangent line of the load-displacement curve (unloading curve) at the start of the unloading process), and the plastic deformation amount H2 on the sample surface after the unloading process (the sample surface after the indenter is released from the sample surface ) was obtained. Then, the elastic modulus (=π ^1/2 S/2Ap ^1/2 ) of the surface of the first resin layer was calculated from the contact stiffness S and the contact projected area Ap. Its elastic modulus (GPa) is shown in Tables 1 and 2.

<Peelability>
For each conductive film for transfer of Examples 1 to 9 and Comparative Examples 1 and 2, the peelability between the temporary support film after the formation of the second resin layer and the first resin layer was evaluated by the following first peel test. The peelability between the temporary support film before the formation of the second resin layer and the first resin layer was examined by the following second peel test.

<First peel test>
First, a first test piece was produced. Specifically, first, the conductive film for transfer (temporary support film/first resin layer/conductive layer/second resin layer) was heated in a hot air oven. The heating temperature was set to 140° C., and the heating time was set to 90 minutes (the same applies to heating described later). This crystallized the conductive layer. Next, a sample film (width 24 mm×length 100 mm) was cut out from the transfer conductive film. Next, the second resin layer side of the sample film was attached to the glass substrate via a strong adhesive. In this bonding, the sample film was press-bonded to the glass substrate by reciprocating a 2-kg hand roller one time in an environment of 23° C. (the same applies to bonding described below). Next, a gripping tape was attached to the temporary support film located on the exposed surface side of the sample film. This gripping tape had a strong adhesive surface, and the gripping tape was attached to the temporary support film of the sample film through the strong adhesive surface (this also applies to attachment of the gripping tape described below). A first test piece was produced as described above.

Next, using a tensile tester, a peel test was carried out in which the temporary support film in the first test piece was peeled from the first resin layer, and the force required for peeling (peeling force) was measured. In this measurement, the measurement temperature is 25 ° C., the temporary support film is peeled from the first resin layer by pulling the gripping tape, the peel angle is 90 °, the pulling speed is 100 mm / min, and the peel length is 100 mm. and Tables 1 and 2 show the average peel strength at peel lengths of 20 to 80 mm as peel strength F1 (N/24 mm).

<Second peel test>
First, a second test piece was produced. Specifically, first, the second intermediate laminate (temporary support film/first resin layer/conductive layer) obtained in the production process of the conductive film for transfer was heated in a hot air oven. Next, a sample film (width 24 mm x length 100 mm) was cut out from the second intermediate laminate. Next, the conductive layer side of the sample film was attached to a glass substrate via a strong adhesive. Next, a gripping tape was attached to the temporary support film located on the exposed surface side of the sample film. A second test piece was produced as described above.

Next, using a tensile tester, a peel test was carried out in which the temporary support film in the second test piece was peeled from the first resin layer, and the peel force was measured. The measurement conditions are the same as the measurement conditions in the first peeling test described above. The average peel force at a peel length of 20 to 80 mm is shown in Tables 1 and 2 as peel strength F2 (N / 24 mm) (when peeling, part of the first resin layer or the first resin layer on the temporary support film side A case where a part of the conductive layer remains is described as "1.1 or more").

〈Crack due to cutting〉
For the first resin layer of the first intermediate laminate obtained in the manufacturing process of the transfer conductive films of Examples 1 to 9 and Comparative Examples 1 and 2, the presence or absence of cracks due to cutting was determined as follows. I checked.

First, the first intermediate laminate (temporary support film/first resin layer/conductive layer) was cut with a paper cutter (product name “Safety NS Model No. 1” manufactured by Uchida Yoko Co., Ltd.) to obtain a cut sample. Next, the cut portion (edge) of the cut sample was observed in the thickness direction from the conductive layer side with an optical microscope (product name "MX61L", manufactured by OLYMPUS) at a magnification of 20 times. When one or more cracks were present in the first resin layer within the field of observation, the maximum length of the crack having the maximum length among the cracks was measured. Five such microscopic observations (five fields of view) were performed for each cut sample to obtain the five maximum lengths, and the average value D of the five maximum lengths was calculated. Then, regarding the suppression of cracks in the first resin layer, when the average value D is less than 200 μm, it is evaluated as “good”, and when the average value D is 200 μm or more and less than 400, it is evaluated as “good”. A case where D was 400 μm or more was evaluated as “improper”. The results are shown in Tables 1 and 2.

X Conductive film for transfer Y Transparent conductive film H Thickness direction S Temporary support film 11 Cured resin layer (first resin layer)
11a surface 12 conductive layer 13 cured resin layer (second resin layer)
10A Intermediate laminate (first intermediate laminate)
10B Intermediate laminate (second intermediate laminate)

Claims (8)

Forming a first resin layer as a cured resin layer in releasable contact with the temporary support film and having a thickness of 3 μm or less on one side in the thickness direction of the temporary support film. , a first step;
a second step of forming a conductive layer on one side in the thickness direction of the first resin layer to obtain a first intermediate laminate;
a third step of cutting the first intermediate laminate to obtain a second intermediate laminate;
a fourth step of forming a second resin layer on one side in the thickness direction of the conductive layer in the second intermediate laminate,
A method for producing a conductive film for transfer, wherein the peel strength between the temporary support film and the first resin layer after the fourth step is 1 N/24 mm or less. The method for producing a conductive film for transfer according to claim 1, wherein the total thickness of the thickness of the first resin layer and the thickness of the second resin layer exceeds 2 µm. 3. The method for producing a conductive film for transfer according to claim 1, wherein the second resin layer has a thickness of 2 [mu]m or more. A temporary support film, a first resin layer as a cured resin layer in releasable contact with the temporary support film, a conductive layer, and a second resin layer in this order in the thickness direction,
The first resin layer has a thickness of 3 μm or less,
A conductive film for transfer, wherein the peel strength between the temporary support film and the first resin layer is 1 N/24 mm or less. The conductive film for transfer according to claim 4, wherein the total thickness of the thickness of the first resin layer and the thickness of the second resin layer exceeds 2 µm. 6. The conductive film for transfer according to claim 4, wherein the second resin layer has a thickness of 2 [mu]m or more. The transfer material according to any one of claims 4 to 6, wherein the surface of the first resin layer on the conductive layer side has an elastic modulus at 25°C measured by a nanoindentation method of 4 GPa or more. conductive film. The conductive film for transfer according to any one of claims 4 to 7, wherein the conductive layer contains an indium-containing conductive oxide.

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