JP7608181B2 - Conductive film transfer material with carrier film and method for manufacturing conductive film transfer material with carrier film - Google Patents

Description

The present invention relates to a conductive film transfer material with a carrier film and a method for manufacturing the conductive film transfer material with a carrier film. More specifically, the present invention relates to a conductive film transfer material with a carrier film and a method for manufacturing the conductive film transfer material with a carrier film.

Conductive films having a conductive layer made of indium tin oxide (ITO) are known. The conductive layer is formed into a desired electrode pattern. The conductive film is used in optical products such as touch panels.

Such conductive films are obtained by forming a conductive layer on the surface of a substrate by a sputtering method while the substrate is being transported. In such cases, a carrier film is provided on the substrate to ensure mechanical strength and improve transportability.

For example, a transparent conductive film laminate has been proposed that includes a carrier film and a transparent conductive film (see, for example, Patent Document 1). The transparent conductive film includes a transparent substrate, a cured resin layer, and a transparent conductive layer.

When manufacturing a product using the transparent conductive film, the carrier film is peeled off from the transparent substrate, and the carrier film is removed from the transparent conductive film laminate.

JP 2020-108941 A

In recent years, transparent conductive films are required to be flex-resistant in order to accommodate flexible displays (foldable, bendable, rollable displays, etc.).

In Patent Document 1, the carrier film and the transparent substrate are peeled off, and the carrier film is removed from the transparent conductive film laminate, so the transparent substrate remains on the transparent conductive film. This makes it impossible to make the transparent conductive film thinner, and the bending resistance is reduced.

The present invention provides a conductive film transfer material with a carrier film that is suitable for producing a conductive film with excellent bending resistance and workability, and a method for producing the same.

The present invention [1] is a conductive film transfer material with a carrier film, which comprises a carrier film, a temporary support, a cured resin layer, and a conductive layer in this order toward one side in the thickness direction, the temporary support and the cured resin layer are peelable, and the peeling force between the temporary support and the cured resin layer is smaller than the peeling force between the carrier film and the temporary support.

The present invention [2] includes the conductive film transfer material with carrier film described in [1] above, in which the peel strength between the temporary support and the cured resin layer is 1.0 N/24 mm or less.

The present invention [3] includes the conductive film transfer material with a carrier film according to the above [1] or [2], in which the amount of warping measured by the following test is −10 mm or more and 10 mm or less.
Test: (1) The conductive film transfer material with carrier film is cut into a square of 100 mm x 100 mm. (2) The cut conductive film transfer material with carrier film is heated at 140°C for 90 minutes. (3) The cut conductive film transfer material with carrier film is placed on a horizontal table with the conductive layer facing up, and the vertical height from the horizontal table is measured at each of the four corners to determine the amount of warping. (4) The obtained amounts of warping are summed up, and the average value is calculated to determine the amount of positive warping. (5) If the amount of positive warping is 0 mm or less, the cut conductive film transfer material with carrier film is placed on a horizontal table with the carrier film facing up, and the vertical height from the horizontal table is measured at each of the four corners to determine the amount of warping. (6) The obtained amounts of warping are summed up, and the average value is calculated to determine the amount of negative warping.

The present invention [4] is a method for producing a conductive film transfer material with a carrier film according to any one of the above [1] to [3], and includes a method for producing a conductive film transfer material with a carrier film, the method including a preparation step for preparing a temporary support, a cured resin layer arrangement step for arranging a cured resin layer on one surface in the thickness direction of the temporary support, a film formation step for forming a conductive layer on one surface in the thickness direction of the cured resin layer, and a carrier film arrangement step for arranging a carrier film on the other surface in the thickness direction of the temporary support.

The present invention [5] includes the method for producing a conductive film transfer material with a carrier film described in the above [4], in which a carrier film arrangement step is carried out after the film formation step.

The conductive film transfer material with carrier film of the present invention comprises a carrier film, a temporary support, a cured resin layer, and a conductive layer in that order toward one side in the thickness direction. The temporary support and the cured resin layer are peelable. Therefore, a conductive film with excellent bending resistance can be produced.

In detail, when manufacturing a conductive film, a carrier film is provided from the viewpoint of ensuring mechanical strength and improving transportability. According to this conductive film transfer material with a carrier film, transportability can be improved by providing a carrier film on the other surface in the thickness direction of the temporary support during transport. In addition, if the temporary support and the cured resin layer are peeled off after transport, the carrier film can be removed together with the temporary support. In this way, a conductive film having a cured resin layer and a conductive layer without a substrate (for example, a transparent substrate) can be obtained. And, since the obtained conductive film does not have a substrate, it is thin and has excellent bending resistance.

Moreover, the peeling force between the temporary support and the cured resin layer is smaller than the peeling force between the carrier film and the temporary support. Therefore, when peeling the temporary support and the cured resin layer, peeling between the carrier film and the temporary support can be suppressed. As a result, when the temporary support and the cured resin layer are peeled off, the carrier film can be removed together with the temporary support. As a result, workability is excellent.

The method for producing a conductive film transfer material with a carrier film of the present invention makes it possible to suitably produce the conductive film transfer material with a carrier film of the present invention.

FIG. 1 shows a cross-sectional view of one embodiment of the conductive film transfer material with a carrier film of the present invention. FIG. 2 shows one embodiment of the manufacturing method of the conductive film transfer material with carrier film of the present invention. FIG. 2A shows a preparation step of preparing a temporary support. FIG. 2B shows a cured resin layer arrangement step of arranging a cured resin layer (hard coat layer) on one surface in the thickness direction of the temporary support. FIG. 2C shows a film formation step of forming a conductive layer on one surface in the thickness direction of the cured resin layer. FIG. 2D shows a carrier film arrangement step of arranging a carrier film on the other surface in the thickness direction of the temporary support. FIG. 2E shows a step of peeling off the carrier film from the conductive film transfer material with carrier film.

With reference to Figure 1, one embodiment of the conductive film transfer material with carrier film of the present invention will be described.

In Figure 1, the up-down direction on the paper surface is the up-down direction (thickness direction), with the upper side of the paper surface being the top side (one side in the thickness direction) and the lower side of the paper surface being the bottom side (the other side in the thickness direction). Additionally, the left-right direction and depth direction on the paper surface are surface directions that are perpendicular to the up-down direction. Specifically, they follow the directional arrows in each figure.

<Conductive film transfer material with carrier film>
The conductive film transfer material 1 with a carrier film has a film shape (including a sheet shape) with a predetermined thickness, extends in a plane direction perpendicular to the thickness direction, and has a flat upper surface and a flat lower surface.

Specifically, as shown in FIG. 1, the conductive film transfer material 1 with a carrier film includes a carrier film 20, a temporary support 2, and a conductive film 10, arranged in this order toward one side in the thickness direction. More specifically, the conductive film transfer material 1 with a carrier film includes a carrier film 20, a temporary support 2 arranged on the upper surface (one side in the thickness direction) of the carrier film 20, and a conductive film 10 arranged on the upper surface (one side in the thickness direction) of the temporary support 2. Preferably, the conductive film transfer material 1 with a carrier film includes only the carrier film 20, the temporary support 2, and the conductive film 10.

As will be described in more detail later, the conductive film 10 does not include a transparent substrate, but includes a cured resin layer 3 and a conductive layer 4, which are arranged in that order toward one side in the thickness direction. Therefore, in more detail, the conductive film transfer material 1 with a carrier film includes a carrier film 20, a temporary support 2, a cured resin layer 3, and a conductive layer 4, which are arranged in that order toward one side in the thickness direction.

The thickness of the conductive film transfer material 1 with carrier film is, for example, 300 μm or less, preferably 150 μm or less, and more preferably 100 μm or less.

<Carrier film>
The carrier film 20 is a protective member that is provided in order to ensure mechanical strength and improve transportability when the conductive film 10 is manufactured.

The carrier film 20 comprises a protective substrate 21 and an adhesive layer 22 in this order toward one side in the thickness direction. More specifically, the carrier film 20 comprises a protective substrate 21 and an adhesive layer 22 disposed on the upper surface (one side in the thickness direction) of the protective substrate 21. Preferably, the carrier film 20 is composed of the protective substrate 21 and the adhesive layer 22.

The protective substrate 21 is a supporting substrate that ensures the mechanical strength of the carrier film 20.

The protective substrate 21 has a film shape.

An example of the protective substrate 21 is a polymer film.

Examples of materials for the polymer film include polyester resin, (meth)acrylic resin, olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, and polystyrene resin. Examples of polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of (meth)acrylic resin include polymethyl methacrylate. Examples of olefin resin include polyethylene, polypropylene, and cycloolefin polymer. Examples of cellulose resin include triacetyl cellulose.

The polymer film material is preferably polyester resin, more preferably polyethylene terephthalate.

The thickness of the protective substrate 21 is, for example, 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and, for example, 200 μm or less, preferably 150 μm or less, more preferably 100 μm or less.

The thickness of the protective substrate 21 can be measured using a dial gauge (PEACOCK, "DG-205").

The adhesive layer 22 is a layer (pressure-sensitive adhesive layer) for attaching the carrier film 20 (protective substrate 21) to the temporary support 2. After attachment, it is also a layer (easy-peel layer) that can be and is easily peeled off from the temporary support 2.

The adhesive layer 22 has a film shape.

The adhesive layer 22 is formed from an adhesive composition.

Examples of adhesive compositions include acrylic adhesive compositions, rubber adhesive compositions, silicone adhesive compositions, polyester adhesive compositions, polyurethane adhesive compositions, polyamide adhesive compositions, epoxy adhesive compositions, vinyl alkyl ether adhesive compositions, and fluorine-based adhesive compositions. These adhesive compositions can be used alone or in combination of two or more types.

From the viewpoint of adhesion and peelability, the adhesive composition is preferably an acrylic adhesive composition.

The acrylic adhesive composition contains, for example, an acrylic polymer obtained by polymerizing a monomer component containing an alkyl (meth)acrylate ester as a polymer component.

The (meth)acrylic acid alkyl ester is an acrylic acid alkyl ester and/or a methacrylic acid alkyl ester. Examples of the (meth)acrylic acid alkyl ester include linear or branched (meth)acrylic acid alkyl esters having an alkyl portion with 4 to 14 carbon atoms. Examples of the (meth)acrylic acid alkyl esters having linear or branched alkyl portions with 4 to 14 carbon atoms include butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, neopentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, and tetradecyl (meth)acrylate. The (meth)acrylic acid alkyl esters can be used alone or in combination of two or more kinds. As the (meth)acrylic acid alkyl ester, preferably, butyl (meth)acrylate is used, and more preferably, butyl acrylate is used.

The mixing ratio of the (meth)acrylic acid alkyl ester is, for example, 80 parts by mass or more, preferably 85 parts by mass or more, and, for example, 99 parts by mass or less, preferably 95 parts by mass or less, per 100 parts by mass of the total amount of the monomer components.

The monomer component may contain a functional group-containing monomer in addition to the (meth)acrylic acid alkyl ester.

Examples of functional group-containing monomers include carboxyl group-containing monomers and hydroxyl group-containing monomers. Examples of carboxyl group-containing monomers include acrylic acid and methacrylic acid. Examples of hydroxyl group-containing monomers include 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate. The functional group-containing monomers can be used alone or in combination of two or more.

As the functional group-containing monomer, preferably, a carboxyl group-containing monomer is used, and more preferably, acrylic acid is used.

The mixing ratio of the functional group-containing monomer is, for example, 1 part by mass or more, for example, 5 parts by mass or more, and 20 parts by mass or less, preferably 15 parts by mass or less, per 100 parts by mass of the total amount of the monomer components.

The acrylic adhesive composition can be obtained, for example, by solution polymerization, bulk polymerization, and photopolymerization.

The adhesive composition preferably contains a crosslinking agent. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based resins, aziridine derivatives, and metal chelate compounds, and preferably epoxy-based crosslinking agents. The crosslinking agents can be used alone or in combination of two or more.

The mixing ratio of the crosslinking agent is, for example, 1 part by mass or more, preferably 4 parts by mass or more, and, for example, 15 parts by mass or less, preferably 10 parts by mass or less, per 100 parts by mass of the polymer component. By adjusting the mixing ratio of the crosslinking agent, the peel strength of the adhesive layer 22 can be adjusted.

The adhesive composition may further contain tackifier resins, processing aids, pigments, flame retardants, fillers, softeners, and antioxidants as appropriate.

The thickness of the adhesive layer 22 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 50 μm or less, preferably 30 μm or less.

To prepare the carrier film 20, an adhesive layer 22 is placed on one surface in the thickness direction of the protective substrate 21.

To place the adhesive layer 22 on one surface of the protective substrate 21 in the thickness direction, an adhesive composition is applied to one surface of the protective substrate 21 in the thickness direction, and if necessary, heated and dried. This places the adhesive layer 22 on one surface of the protective substrate 21 in the thickness direction.

When the adhesive composition contains a crosslinking agent, the crosslinking reaction proceeds simultaneously with the above drying or by subsequent aging. The aging conditions are appropriately set depending on the type of crosslinking agent. The aging temperature is, for example, 20°C or higher and, for example, 160°C or lower. The aging time is, for example, 1 minute or longer and, for example, 7 days or shorter.

In addition, before or after aging, a release film (not shown) may be laminated on one surface in the thickness direction of the adhesive layer 22. An example of the release film is polyethylene terephthalate.

This prepares the carrier film 20.

<Temporary Support>
The temporary support 2 has a film shape and is disposed on the entire lower surface of the conductive film 10 (cured resin layer 3) so as to be in contact with the lower surface of the conductive film 10 (cured resin layer 3).

The temporary support 2 can be peeled off from the cured resin layer 3.

As will be described in more detail later, this allows the carrier film 20 to be peeled off together with the temporary support 2.

More specifically, the peeling force between the temporary support 2 and the cured resin layer 3 is smaller than the peeling force between the carrier film 20 and the temporary support 2.

Therefore, when peeling the temporary support 2 from the cured resin layer 3, peeling of the carrier film 20 from the temporary support 2 can be suppressed. As a result, when the temporary support 2 and the cured resin layer 3 are peeled off, the carrier film 20 can be removed together with the temporary support 2. As a result, workability is excellent.

On the other hand, if the peeling force between the temporary support 2 and the cured resin layer 3 is greater than the peeling force between the carrier film 20 and the temporary support 2, the carrier film 20 and the temporary support 2 will peel off before the temporary support 2 and the cured resin layer 3 peel off. In that case, the temporary support 2 cannot be removed together with the carrier film 20 (in other words, the temporary support 2 and the carrier film 20 cannot be peeled off at the same time). As a result, workability is reduced.

Specifically, the peel strength between the temporary support 2 and the cured resin layer 3 is, for example, 1.0 N/24 mm or less, preferably 0.5 N/24 mm or less, and for example, 0.01 N/24 mm or more.

The peeling force between the carrier film 20 and the temporary support 2 is, for example, 1.5 N/24 mm or less, preferably 1.0 N/24 mm or less, and for example, 0.02 N/24 mm or more.

The difference between the peeling force of the carrier film 20 and temporary support and the peeling force of the temporary support 2 and cured resin layer 3 (the peeling force of the carrier film 20 and temporary support - the peeling force of the temporary support 2 and cured resin layer 3) is, for example, 0.01 N/24 mm or more, preferably 0.2 N/24 mm or more, and, for example, 1.5 N/24 mm or less, preferably 1.0 N/24 mm or less, more preferably 0.5 N/24 mm or less.

If the peel strength is equal to or less than the upper limit, the temporary support 2 and the cured resin layer 3 can be easily peeled off.

The peel strength can be measured by the peel test described in the examples below.

The temporary support 2 can be, for example, a flexible plastic film. Examples of materials for the flexible plastic film include olefin resins and polyester resins. Examples of olefin resins include polyethylene, polypropylene, and cycloolefin polymers. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

The thickness of the temporary support 2 is, for example, 3 μm or more, preferably 10 μm or more, and, for example, 200 μm or less, preferably 100 μm or less, more preferably 50 μm or less.

The temporary support 2 is preferably subjected to a release treatment in order to adjust the peel strength to the above range. Examples of the release treatment include a release treatment using a silicone-based, fluorine-based, long-chain alkyl-based, or fatty acid amide-based release agent, or a release treatment using silica powder.

<Conductive film>
The conductive film 10 includes a cured resin layer 3 and a conductive layer 4 in this order toward one side in the thickness direction. More specifically, the conductive film 10 includes a cured resin layer 3 and a conductive layer 4 disposed on the upper surface (one surface in the thickness direction) of the cured resin layer 3. Preferably, the conductive film 10 includes only the cured resin layer 3 and the conductive layer 4. The conductive film 10 is, for example, a part of a touch panel substrate or an electromagnetic wave shield provided in an image display device, that is, it is not an image display device. In other words, the conductive film 10 is a part for producing an image display device or the like, does not include an image display element such as an OLED module, is distributed as a part alone, and is an industrially applicable device.

<Cured Resin Layer>
The cured resin layer 3 has a film shape and is disposed on the entire lower surface of the conductive layer 4 so as to be in contact with the lower surface of the conductive layer 4.

The cured resin layer 3 can be a hard coat layer.

In the following explanation, we will explain the case where the cured resin layer 3 is a hard coat layer.

The hard coat layer is a protective layer that prevents scratches on the conductive layer 4.

The hard coat layer is formed, for example, from a hard coat composition.

The hard coat composition contains a resin and, if necessary, particles. That is, the hard coat layer contains a resin and, if necessary, particles.

Examples of resins include thermoplastic resins and curable resins. Examples of thermoplastic resins include polyolefin resins.

Examples of the curable resin include active energy ray curable resins that are cured by irradiation with active energy rays (e.g., ultraviolet rays and electron beams) and thermosetting resins that are cured by heating. Examples of the curable resin include active energy ray curable resins.

Examples of active energy ray-curable resins include (meth)acrylic ultraviolet-curable resins, urethane resins, melamine resins, alkyd resins, siloxane-based polymers, and organic silane condensates. Examples of active energy ray-curable resins include (meth)acrylic ultraviolet-curable resins.

The resin may also contain, for example, a reactive diluent as described in JP 2008-88309 A. Specifically, the resin may contain a polyfunctional (meth)acrylate.

Resins can be used alone or in combination of two or more types.

Examples of the particles include metal oxide fine particles and organic fine particles. Examples of materials for metal oxide fine particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials for organic fine particles include polymethyl methacrylate, silicone, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate.

The particles can be used alone or in combination of two or more types.

Then, by adjusting the particle blend ratio and/or the average particle size of the particles to a predetermined ratio, the arithmetic mean roughness Ra of the conductive layer 4 described below can be adjusted to a predetermined range described below.

Specifically, the mixing ratio of the particles is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and for example, 10 parts by mass or more, and for example, 20 parts by mass or less, per 100 parts by mass of resin.

If the particle blending ratio is equal to or less than the upper limit, the arithmetic mean roughness Ra of the conductive layer 4 described below can be adjusted to fall within a specified range described below.

The average particle diameter of the particles is, for example, 10 μm or less, preferably 8 μm or less, and for example, 1 nm or more. When nanoparticles are used as the particles, the average particle diameter of the particles is, for example, 100 nm or less, preferably 70 nm or less, and for example, 1 nm or more. The average particle diameter of the particles is determined, for example, as the D50 value (cumulative 50% median diameter) based on the particle size distribution determined by a particle size distribution measurement method in a laser scattering method.

If the average particle size of the particles is within the above range, the arithmetic mean roughness Ra of the conductive layer 4 described below can be adjusted to a specified range described below.

If necessary, the hard coat composition may contain a thixotropy-imparting agent, a photopolymerization initiator, a filler (e.g., organic clay), and a leveling agent in appropriate proportions. The hard coat composition may also be diluted with a known solvent.

To form a hard coat layer, a diluted solution of the hard coat composition is applied to one surface in the thickness direction of the temporary support 2, and if necessary, heated and dried. After drying, the hard coat composition is cured, for example, by irradiation with active energy rays.

This forms a hard coat layer.

The thickness of the hard coat layer is, for example, 1 μm or more and 7 μm or less, preferably 3 μm or less, more preferably 2.5 μm or less, and even more preferably 1.5 μm or less.

The thickness of the hard coat layer can also be measured by cross-sectional observation using, for example, a transmission electron microscope.

<Conductive Layer>
The conductive layer 4 is amorphous or crystalline, and is preferably a transparent layer (transparent conductive layer) that exhibits excellent electrical conductivity.

The conductive layer 4 has a film shape. The conductive layer 4 is disposed on the entire upper surface of the cured resin layer 3 so as to be in contact with the upper surface of the cured resin layer 3.

Examples of materials for the conductive layer 4 include metal oxides. The metal oxides contain at least one metal element selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. If necessary, the metal oxides may be doped with a metal element in the above group.

Examples of the conductive layer 4 include indium-containing oxides and antimony-containing oxides. Examples of the indium-containing oxides include indium tin oxide (ITO). Examples of the antimony-containing oxides include antimony tin oxide (ATO). From the viewpoint of low resistance, the conductive layer 4 is preferably an indium-containing oxide, and more preferably ITO.

When ITO is used as the material of the conductive layer 4, the tin oxide ( _SnO2 ) content is, for example, 0.5 mass% or more, preferably 3 mass% or more, more preferably 5 mass% or more, _and for example, 15 mass% or less, preferably 13 mass% or less, based on the total amount of _tin oxide and indium oxide (In2O3). If the tin oxide content is equal to or more than the above lower limit, the durability of the ITO layer can be further improved. If the tin oxide content is equal to or less than the above upper limit, the crystallization of the ITO layer can be facilitated, and the stability of the transparency and resistivity can be improved.

In this specification, "ITO" refers to a composite oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Examples of additional components include metal elements other than In and Sn. Specific examples of such metal elements include Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, Fe, Pb, Ni, Nb, Cr, and Ga.

The conductive layer 4 is preferably crystalline.

If the conductive layer 4 is crystalline, the surface resistivity, which will be described later, can be reduced.

The crystallinity of the conductive layer 4 can be determined, for example, by immersing the conductive film 10 in hydrochloric acid (20°C, concentration 5% by mass) for 15 minutes, followed by rinsing and drying, and then measuring the inter-terminal resistance at a distance of about 15 mm from the surface on the conductive layer 4 side. If the inter-terminal resistance at a distance of 15 mm in the conductive film 10 after the above immersion, rinsing and drying is 10 kΩ or less, the conductive layer 4 is crystalline. On the other hand, if the resistance exceeds 10 kΩ, the conductive layer 4 is amorphous.

The resistivity of the upper surface of the conductive layer 4 is, for example, 20×10 ⁻⁴ Ω·cm or less, preferably 8.0×10 ⁻⁴ Ω·cm or less, and for example, 0.1×10 ⁻⁴ Ω·cm or more. The resistivity can be measured by a four-terminal method in accordance with JIS K7194 (1994).

The surface resistivity of the upper surface of the conductive layer 4 is, for example, 150 Ω/□ or less, preferably 50 Ω/□ or less, and for example, 0.1 Ω/□ or more. The surface resistivity can be measured by a four-terminal method in accordance with JIS K7194 (1994).

If the surface resistivity is equal to or less than the upper limit, the conductive film 10 can be used, for example, in a large touch panel.

The arithmetic mean roughness Ra of the conductive layer 4 (more specifically, the arithmetic mean roughness Ra of one surface in the thickness direction of the conductive layer 4) is, for example, 7.0 nm or less, preferably 1.5 nm or less, and for example, 0.2 nm or more.

The conductive layer 4 is determined, for example, from an observation image of 1 μm square taken with an AFM (atomic force microscope) in accordance with JIS B0681-6 (2017).

The conductive layer 4 has a thickness of, for example, 10 nm or more, preferably 30 nm or more, and for example, 150 nm or less, preferably 100 nm or less, more preferably 70 nm or less. The thickness of the conductive layer 4 can be measured by observing a cross section of the conductive film 10 using, for example, a transmission electron microscope.

The total light transmittance (JIS K 7375-2008) of the conductive layer 4 is, for example, 50% or more, preferably 60% or more.

<Method of manufacturing conductive film transfer material with carrier film>
The manufacturing method of the conductive film transfer material 1 with a carrier film includes a preparation process of preparing a temporary support 2, a cured resin layer arrangement process of arranging a cured resin layer 3 (hard coat layer) on one thickness-wise surface of the temporary support 2, a film formation process of forming a conductive layer 4 on one thickness-wise surface of the cured resin layer 3, and a carrier film arrangement process of arranging a carrier film 20 on the other thickness-wise surface of the temporary support 2.

In addition, in this manufacturing method, a carrier film placement process is preferably carried out after the film formation process.

If the carrier film placement process is carried out after the film formation process, the carrier film 20 is not placed during the film formation process, so that impurity gas originating from the carrier film 20 can be prevented from impeding the formation of the conductive layer 4.

In the preparation step, a temporary support 2 is prepared as shown in Figure 2A.

In the cured resin layer placement process, as shown in FIG. 2B, a cured resin layer 3 (hard coat layer) is placed on one surface in the thickness direction of the temporary support 2.

To place the cured resin layer 3 (hard coat layer) on one side of the temporary support 2 in the thickness direction, first, a surface treatment is performed on the surface of the temporary support 2 (the surface that has been subjected to the above-mentioned release treatment, or the surface that has not been subjected to the above-mentioned release treatment).

Examples of surface treatments include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, and saponification treatment. A preferred surface treatment is plasma treatment.

Next, a diluted solution of the hard coat composition is applied to one surface in the thickness direction of the temporary support 2, and after drying, the hard coat composition is cured by ultraviolet light irradiation or heating. This forms a cured resin layer 3 (hard coat layer) on one surface in the thickness direction of the temporary support 2. This results in a conveying sheet 30 that includes the temporary support 2 and the cured resin layer 3 in order toward one side in the thickness direction.

In the film-forming process, as shown in FIG. 2C, a conductive layer 4 is formed on one surface in the thickness direction of the cured resin layer 3.

To form the conductive layer 4 on one side of the cured resin layer 3 in the thickness direction, first, wrap the conveying sheet 30 around a delivery roll (not shown).

Next, the conveying sheet 30 is sent out from the sending roll. Then, while the conveying sheet 30 is conveyed downstream in the conveying direction, the conductive layer 4 is formed on one surface in the thickness direction of the cured resin layer 3 by the sputtering method.

The conveying speed is, for example, 1 m/min or more, preferably 2 m/min or more, and, for example, 10 m/min or less, preferably 7 m/min or less.

In the sputtering method, a target (material for the conductive layer 4) and the cured resin layer 3 are placed facing each other in a vacuum chamber. Next, gas is supplied and a voltage is applied from a power source. This accelerates gas ions and irradiates the target, ejecting the target material from the target surface. The target material is then deposited on one side of the cured resin layer 3 in the thickness direction.

The gas may be, for example, an inert gas. The inert gas may be, for example, argon gas. If necessary, a reactive gas (for example, oxygen gas) may be used in combination. When a reactive gas is used in combination, the flow rate ratio (sccm) of the reactive gas is not particularly limited. Specifically, the flow rate ratio of the reactive gas is, for example, 0.1 flow rate% or more and 100 flow rate% or less with respect to the total flow rate ratio of the sputtering gas and the reactive gas.

The air pressure during sputtering is, for example, 0.1 Pa or more, and, for example, 1.0 Pa or less, preferably 0.7 Pa or less.

The power source may be, for example, a DC power source, an AC power source, an MF power source, or an RF power source. It may also be a combination of these.

The discharge output is, for example, 10 kW or more, preferably 20 kW or more, and, for example, 305 kW or less.

This places the conductive layer 4 on one side of the cured resin layer 3 in the thickness direction.

In the carrier film placement process, as shown in FIG. 2D, a carrier film 20 is placed on the other side in the thickness direction of the temporary support 2. To place the carrier film 20 on the other side in the thickness direction of the temporary support 2, first, the carrier film 20 is prepared by the method described above.

Then, the carrier film 20 is placed on the other side of the temporary support 2 in the thickness direction via the adhesive layer 22 on the carrier film 20.

Then, in order to improve the crystallinity, the formed conductive layer 4 can be heated. The heating temperature is, for example, 80°C or more and 160°C or less. The heating time is, for example, 10 minutes or more and, for example, 120 minutes or less.

By the above steps, a conductive film transfer material 1 with a carrier film is obtained, which has a carrier film 20, a temporary support 2, a cured resin layer 3, and a conductive layer 4 in that order toward one side in the thickness direction.

The amount of warping of the conductive film transfer material 1 with carrier film, measured by the following test, is, for example, -10 mm or more, preferably -5 mm or more, more preferably -3 mm or more, and for example, 10 mm or less, preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 2 mm or less.

In the test, first, the conductive film transfer material 1 with the carrier film is cut into a square of 100 mm x 100 mm. The cut conductive film transfer material 1 with the carrier film is heated at 140°C for 90 minutes. Next, the cut conductive film transfer material 1 with the carrier film is placed on a horizontal stand with the conductive layer 4 facing up, and the vertical height from the horizontal stand is measured at each of the four corners to determine the amount of warping. The obtained amounts of warping are added up, their average value is calculated, and this is determined as the positive amount of warping. If the positive amount of warping is 0 mm or less, the cut conductive film transfer material 1 with the carrier film is placed on a horizontal stand with the carrier film 20 facing up, and the vertical height from the horizontal stand is measured at each of the four corners to determine the amount of warping. The obtained amounts of warping are added up, their average value is calculated, and this is determined as the negative amount of warping.

If the amount of warping is within the above range, transportability is excellent.

When manufacturing a product using the conductive film 10, the carrier film 20 is peeled off from the conductive film transfer material 1 with the carrier film, as shown in FIG. 2E. Specifically, the temporary support 2 and the cured resin layer 3 are peeled off, and the carrier film 20 is peeled off together with the temporary support 2.

This results in a conductive film 10 having a cured resin layer 3 and a conductive layer 4 in sequence toward one side in the thickness direction.

The conductive layer 4 can also be patterned before or after peeling off the carrier film 20. The patterning can be performed, for example, by etching.

<Action and effect>
The conductive film transfer material 1 with a carrier film includes a carrier film 20, a temporary support 2, a cured resin layer 3 (hard coat layer), and a conductive layer 4 in this order toward one side in the thickness direction. The temporary support 2 and the cured resin layer 3 (hard coat layer) are peelable. Therefore, a conductive film 10 with excellent bending resistance can be produced.

In detail, when the conductive film 10 is manufactured, the carrier film 20 is provided from the viewpoint of ensuring mechanical strength and improving transportability. According to this conductive film transfer material 1 with a carrier film, transportability can be improved by providing the carrier film 20 on the other surface in the thickness direction of the temporary support 2 during transport. In addition, if the temporary support 2 and the cured resin layer 3 are peeled off after transport, the carrier film 20 can be removed together with the temporary support 2. In this way, a conductive film 10 that does not include a substrate (for example, a transparent substrate) and includes the cured resin layer 3 and the conductive layer 4 can be obtained. And, since the obtained conductive film 10 does not include a substrate, it is thin and has excellent bending resistance.

In addition, the peeling force between the temporary support 2 and the cured resin layer 3 is smaller than the peeling force between the carrier film 20 and the temporary support 2. Therefore, when peeling the temporary support 2 and the cured resin layer 3, peeling between the carrier film 20 and the temporary support 2 can be suppressed. As a result, when the temporary support 2 and the cured resin layer 3 are peeled off, the carrier film 20 can be removed together with the temporary support 2. As a result, workability is excellent.

This manufacturing method for the conductive film transfer material 20 with a carrier film makes it possible to suitably manufacture the conductive film transfer material 1 with a carrier film.

<Modification>
In the modified example, the same components and steps as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, the modified example can achieve the same effects as those in the first embodiment, unless otherwise specified. Furthermore, the first embodiment and its modified example can be appropriately combined.

In the above description, the cured resin layer 3 is a hard coat layer, but the cured resin layer 3 may be an optical adjustment layer.

The optical adjustment layer is a layer that adjusts the optical properties (e.g., refractive index) of the conductive film 10 to suppress the visibility of the pattern of the conductive layer 4 and to suppress reflection at the interface within the conductive film 10 while ensuring excellent transparency of the conductive film 10.

The cured resin layer 3 can also be a combination of a hard coat layer and an optical adjustment layer (multilayer including a hard coat layer and an optical adjustment layer).

The present invention will be described in more detail below with reference to examples and comparative examples. Note that the present invention is in no way limited to the examples and comparative examples. In addition, the specific numerical values of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "equal to or less than") or lower limit values (numerical values defined as "equal to or more than" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention".

1. Production of a conductive film transfer material with a carrier film Example 1
<Preparation process>
As a temporary support, a polyethylene terephthalate substrate (trade name "Panapeel" TP series, manufactured by PANAC Corporation) having one side subjected to a release treatment was prepared.

<Cured resin layer arrangement process>
A hard coat composition was prepared containing 100 parts by mass of an ultraviolet-curable resin composition (manufactured by DIC Corporation, product name "Luxidia (registered trademark) V-6000") and 3 parts by mass of a photoreaction initiator.

Then, the hard coat composition was applied to the release-treated surface of the temporary support using a gravure coater so that the thickness after drying was 1 μm. Then, the coating film was heated at 80° C. Next, the hard coat composition was cured by irradiating ultraviolet rays with an integrated light amount of 250 mJ/cm ² from a high-pressure mercury lamp. As a result, a hard coat layer was formed on one surface in the thickness direction of the temporary support, and a conveying sheet was obtained.

<Film formation process>
A sintered target containing indium oxide and tin oxide in a mass ratio of 90:10 was attached to a parallel plate type winding magnetron sputtering device, and while conveying a conveying sheet, the device was evacuated to a vacuum until the partial pressure of water became 5×10 ⁻⁴ Pa. Thereafter, the amount of argon gas and oxygen gas introduced was adjusted, and while conveying the conveying sheet at a conveying speed of 4.0 m/min and a conveying tension of 200 to 500 N, a film was formed on one surface in the thickness direction of the hard coat layer by DC sputtering at an output of 24.2 kW. As a result, a conductive layer (ITO layer) having a thickness of 50 nm was formed on one surface in the thickness direction of the hard coat layer.

<Carrier film placement process>
As a protective substrate, a PET film having a thickness of 125 μm was prepared.

Next, an adhesive composition was prepared. Specifically, an acrylic polymer was obtained by solution polymerization of a monomer component containing butyl acrylate/acrylic acid (100/6). 6 parts by weight of an epoxy crosslinking agent was added to 100 parts by weight of this acrylic polymer to prepare an adhesive composition.

Next, this adhesive composition was applied to one surface in the thickness direction of a PET film (protective substrate) and heated at 150°C for 90 seconds to form an adhesive layer with a thickness of 10 μm. Next, the silicone-treated surface of a 25 μm-thick PET film (release liner) that had been silicone-treated was attached to one surface in the thickness direction of this adhesive layer, and the resulting mixture was stored at 50°C for two days. This resulted in a carrier film.

Then, the PET film (release liner) was peeled off, and one side of the pressure-sensitive adhesive layer in the thickness direction was bonded to the other side of the temporary support in the thickness direction. This resulted in a conductive film with a carrier film having a carrier film, a temporary support, a hard coat layer, and a conductive layer in that order toward one side in the thickness direction.

Examples 2 and 3
A conductive film with a carrier film was obtained in the same manner as in Example 1. However, the thickness of the hard coat layer was changed according to Table 1.

Example 4
A conductive film transfer material with a carrier film was obtained in the same manner as in Example 1. However, after the carrier film arrangement step, a heat treatment was carried out in a heated oven at 140° C. for 90 minutes to cause the conductive layer to crystallize.

Example 5
A conductive film transfer material with a carrier film was obtained in the same manner as in Example 1. However, in the cured resin layer arrangement step, a hard coat composition was used in which an ultraviolet curable resin composition (manufactured by DIC Corporation, product name "Unidic ELS888") and an ultraviolet curable resin composition (manufactured by DIC Corporation, product name "Unidic RS28-605") were mixed in a weight ratio of 8:2.

Example 6
A conductive film transfer material with a carrier film was obtained in the same manner as in Example 1. However, in the cured resin layer arrangement step, a hard coat composition was used in which an ultraviolet curable resin composition (manufactured by DIC Corporation, product name "Unidic ELS888") and an ultraviolet curable resin composition (manufactured by DIC Corporation, product name "Unidic RS28-605") were mixed in a weight ratio of 2:8. The thickness of the hard coat layer was changed according to Table 1.

Comparative Example 1 and Comparative Example 2
A conductive film with a carrier film was obtained in the same manner as in Example 1. However, the thickness of the hard coat layer was changed according to Table 1. In addition, after the carrier film arrangement step, a heat treatment was performed at 140° C. for 90 minutes in a heated oven to convert the conductive layer into a crystal.

Comparative Example 3
The preparation step, the cured resin layer disposing step, and the film forming step were carried out in the same manner as in Example 1. That is, the carrier film disposing step was not carried out in Comparative Example 3. As a result, a laminate including a temporary support, a hard coat layer, and a conductive layer 4 in this order toward one side in the thickness direction was obtained.

2. Evaluation (peel strength)
The peel strength (the peel strength between the temporary support and the cured resin layer, and the peel strength between the carrier film and the temporary support) was measured by a peel test (flat cross-stage method) using an adhesive/film peeling analyzer VPA-2 manufactured by Kyowa Interface Science Co., Ltd. The results are shown in Table 1. The method for measuring the peel strength between the temporary support and the cured resin layer, and the method for measuring the peel strength between the carrier film and the temporary support will be specifically described below.

First, the method for measuring the peel force between the temporary support and the cured resin layer will be described in detail. First, in each example and each comparative example, a preparation process, a cured resin layer arrangement process, and a film formation process were carried out in order to create a first peel force test sample having a temporary support, a temporary support, a cured resin layer, and a conductive layer in that order toward one side in the thickness direction.

The peel strength between the temporary support and the cured resin layer was measured for the first peel strength test sample according to the following steps. Note that in Examples 1 to 3, 5, and 6, the following steps B to F were performed, and in Example 4 and Comparative Examples 1 and 2, the following steps A to F were performed.
Step A: The first peel force test sample was heated in a hot air oven at 140° C. for 90 minutes.
Step B: First peel force test samples were cut to 24 mm x 100 mm.
Step C: A glass substrate was attached to one surface in the thickness direction of the conductive layer of the first peel strength test sample via an adhesive layer having a peel strength of 5 N/24 mm or more. A roller was used for attachment.
Step D: A 24 mm x 150 mm adhesive tape (Sekisui Cellotape No. 252) was attached to the other surface in the thickness direction of the temporary support of the conductive film transfer material by 24 mm x 100 mm. In other words, of the 24 mm x 150 mm adhesive tape, 24 mm x 100 mm was the attached portion and 24 mm x 50 mm was the unattached portion. A roller was used for the attachment.
Step E: The sample prepared in step D was set on the stage, and the unattached portion of the adhesive tape (Sekisui Cellotape No. 252) was attached to the measurement probe.
Step F: The peel distance from the unbonded portion and the bonded portion was set to 0 mm, and the average peel force from a movement of 20 mm to 80 mm (peel speed: 0.1 m/min, peel angle: 90°) was calculated as the peel force.

Next, the method for measuring the peel strength between the carrier film and the temporary support will be described in detail. First, in each example and each comparative example, the non-release treated side of a polyethylene terephthalate substrate (manufactured by PANAC Corporation, product name "Panapeel" TP series) with one side subjected to release treatment was attached to the adhesive side of the carrier film. A roller was used for the attachment. In this way, a second peel strength test sample comprising a carrier film and a temporary support was created.

The peel strength between the carrier film and the temporary support was measured for the second peel strength test sample according to the following steps. In Examples 1 to 3, 5, and 6 and Comparative Example 1, the following steps H to M were performed, and in Example 4 and Comparative Example 2, the following steps G to M were performed.
Step G: The second peel force test sample was heated in a hot air oven at 140° C. for 90 minutes.
Step H: A second peel force test sample was cut to 24 mm x 100 mm.
Step I: A glass substrate was attached to the temporary support surface of the second peel strength test sample via an adhesive layer having a peel strength of 5 N/24 mm or more using a roller.
Step J: A 24 mm x 150 mm adhesive tape (Sekisui Cellotape No. 252) was attached to the carrier film surface of the second peel strength test sample by 24 mm x 100 mm. In other words, of the 24 mm x 150 mm adhesive tape, 24 mm x 100 mm was the attached portion and 24 mm x 50 mm was the unattached portion. A roller was used for the attachment.
Step K: The sample prepared in step D was set on the stage, and the unattached portion of the adhesive tape (Sekisui Cellotape No. 252) was attached to the measurement probe.
Step M: The peel distance from the unbonded portion and the bonded portion was set to 0 mm, and the average peel force from a movement of 20 mm to 80 mm was calculated as the peel force (peel speed: 0.1 m/min, peel angle: 90°).

(Removability)
The peelability was evaluated according to the following criteria, and the results are shown in Table 1.
Criterion ◯: In the above evaluation of peel strength, the peel strength between the temporary support and the cured resin layer is smaller than the peel strength between the carrier film and the temporary support.
×: In the above peel strength evaluation, the peel strength between the temporary support and the cured resin layer is greater than the peel strength between the carrier film and the temporary support.

(Warpage amount)
The conductive film transfer material with carrier film of each Example and Comparative Example was cut into a square of 100 mm x 100 mm. The cut conductive film transfer material with carrier film was heated at 140 ° C for 90 minutes. Next, the cut conductive film transfer material with carrier film was placed on a horizontal table with the conductive layer 4 facing up, and the vertical height from the horizontal table was measured at each of the four corners to determine the amount of warping. The obtained amounts of warping were summed up, and the average value was calculated to determine the positive amount of warping. When the positive amount of warping was 0 mm or less, the cut conductive film transfer material with carrier film was placed on a horizontal table with the carrier film facing up, and the vertical height from the horizontal table was measured at each of the four corners to determine the amount of warping. The obtained amounts of warping were summed up, and the average value was calculated to determine the negative amount of warping. The results are shown in Table 1.

3. Discussion Examples 1 to 6, in which the peeling force between the temporary support and the cured resin layer is smaller than the peeling force between the carrier film and the temporary support, are excellent in peelability. That is, in Examples 1 to 6, the temporary support and the cured resin layer peel off before the carrier film and the temporary support peel off, so that the carrier film can be removed together with the temporary support. As a result, it is found that the workability is excellent. And, by the above peeling, a conductive film having a cured resin layer and a conductive layer without a substrate (for example, a transparent substrate) can be obtained. The obtained conductive film is thin and has excellent bending resistance because it does not have a substrate.

On the other hand, in Comparative Examples 1 and 2, in which the peeling force between the temporary support and the cured resin layer is greater than the peeling force between the carrier film and the temporary support, the peelability is reduced. That is, in Comparative Examples 1 and 2, the carrier film and the temporary support peel off before the temporary support and the cured resin layer peel off. As a result, the temporary support cannot be removed together with the carrier film (the temporary support and the carrier film cannot be peeled off at the same time). As a result, workability is reduced.

REFERENCE SIGNS LIST 1 Conductive film transfer material with carrier film 2 Temporary support 3 Cured resin layer 4 Conductive layer 10 Conductive film 20 Carrier film

Claims (5)

A carrier film, a temporary support, a cured resin layer, and a conductive layer are provided in this order toward one side in a thickness direction,
the temporary support and the cured resin layer are peelable from each other,
a peel strength between the temporary support and the cured resin layer is smaller than a peel strength between the carrier film and the temporary support,
The thickness of the cured resin layer is 7 μm or less,
The conductive film transfer material with a carrier film, wherein the conductive layer has a thickness of 150 nm or less . The conductive film transfer material with carrier film according to claim 1, wherein the peel strength between the temporary support and the cured resin layer is 1.0 N/24 mm or less. 3. The conductive film transfer material with a carrier film according to claim 1, wherein the amount of warping measured by the following test is −10 mm or more and 10 mm or less.
Test: (1) The conductive film transfer material with the carrier film is cut into a square of 100 mm x 100 mm.
(2) The cut conductive film transfer material with the carrier film is heated at 140° C. for 90 minutes.
(3) The cut conductive film transfer material with carrier film is placed on a horizontal table with the conductive layer facing up, and the vertical height from the horizontal table is measured at each of the four corners to obtain the amount of warping.
(4) The obtained amounts of warping are totaled, the average value is calculated, and this is regarded as the amount of positive warping.
(5) If the amount of positive warping is 0 mm or less, the cut conductive film transfer material with carrier film is placed on a horizontal table with the carrier film facing up, and the vertical height from the horizontal table at each of the four corners is measured to determine the amount of warping.
(6) The measured warpage amounts are totaled, and the average value is calculated and regarded as the negative warpage amount. A method for producing the conductive film transfer material with a carrier film according to any one of claims 1 to 3, comprising the steps of:
A preparation step of preparing a temporary support;
a cured resin layer disposing step of disposing a cured resin layer on one surface in a thickness direction of the temporary support;
a film forming step of forming a conductive layer on one surface in a thickness direction of the cured resin layer;
A method for producing a conductive film transfer material with a carrier film, comprising: a carrier film disposing step of disposing a carrier film on the other surface in the thickness direction of the temporary support. The method for producing a conductive film transfer material with a carrier film according to claim 4, wherein a carrier film arrangement process is carried out after the film formation process.

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