JP7300855B2 - FILM LAMINATE AND METHOD FOR MANUFACTURING PATTERNED CONDUCTIVE FILM - Google Patents

Description

TECHNICAL FIELD The present invention relates to a film laminate and a method for producing a patterned conductive film using the same.

Conventionally, it is known that an image display device is provided with a conductive film as a film for a touch panel, in which a conductive layer made of indium tin composite oxide (ITO) or metal nanowires is arranged on a transparent base material (for example, See Patent Document 1).

Such a conductive film is, for example, subjected to heat treatment for crystallization of ITO and curing of the binder resin for metal nanowires after patterning the conductive layer into a desired shape.

JP 2017-71850 A

By the way, in order to further reduce the thickness of the conductive film, the use of a thin film base material as a transparent base material is being studied. Then, in the heat treatment, from the viewpoint of eliminating the lack of strength of the conductive film during transportation, the patterned conductive film using a thin base material having a thickness of less than 50 μm is heated while the carrier film is laminated. Further, lamination of a carrier film is particularly required for a conductive film using a thin base material having a thickness of less than 20 μm.

However, due to the difference in thermophysical properties between the carrier film and the conductive film, the conductive film shrinks, causing a problem that the pattern changes from the beginning of patterning.

INDUSTRIAL APPLICABILITY The present invention provides a film laminate capable of suppressing dimensional change of a pattern while achieving thickness reduction, and a method for producing a patterned conductive film using the same.

The present invention [1] is a film laminate including a carrier film and a conductive film in the thickness direction, wherein the conductive film includes a transparent substrate and a conductive layer in the thickness direction, and the carrier film includes a protective group. The thickness of the transparent base material is less than 20 μm, the thermal shrinkage rate of the protective base material is 0.20% or less, and the coefficient of linear thermal expansion between the protective base material and the conductive film is Including film laminates where the difference is 40 ppm/°C or less.

The present invention [2] includes the film laminate according to [1], wherein the transparent substrate is a cycloolefin film.

The present invention [3] includes the film laminate according to [1] or [2], wherein the linear thermal expansion coefficient of the transparent substrate is 60 ppm/°C or more.

The present invention [4] includes the film laminate according to [3], wherein the conductive film further includes a metal layer arranged in the thickness direction of the conductive layer.

The present invention [5] provides a step of preparing the film laminate according to any one of [1] to [4], a step of patterning the conductive layer, a step of heating the film laminate, and removing the carrier film from the film stack.

According to the method for producing a patterned conductive film of the present invention using the film laminate of the present invention, it is possible to produce a patterned conductive film that is reduced in thickness while suppressing dimensional changes.

1A-B show a first embodiment of the film laminate of the present invention, FIG. 1A showing a cross-sectional view and FIG. 1B showing a perspective view. FIG. 2 shows a perspective view of a state in which the protective substrate and the film laminate shown in FIG. 1A are wound into a roll. 3A-3D show process diagrams for manufacturing a heated patterned conductive film from the film stack shown in FIG. 1A, FIG. 3A being the preparation process, FIG. 3B being the patterning process, FIG. FIG. 3D shows the stripping process. FIG. 4 shows a cross-sectional view of a second embodiment of the film laminate of the present invention. 5A-5D show process diagrams for manufacturing a heated patterned conductive film from the film laminate shown in FIG. 4, FIG. 5A being the preparation process, FIG. 5B being the patterning process, FIG. FIG. 5D shows the stripping process. FIG. 6 shows the patterning of the transparent conductive layer when evaluating dimensional changes in the examples.

In FIG. 1A, the vertical direction on the page is the vertical direction (thickness direction), the upper side on the page is the upper side (one side in the thickness direction), and the lower side on the page is the lower side (the other side in the thickness direction). Further, in FIG. 1A, the left-right direction and the depth direction of the paper surface are plane directions orthogonal to the up-down direction. Specifically, in FIG. 1A, the depth direction of the paper is the first direction (the direction perpendicular to the thickness direction, the first direction in the surface direction). on the side. In FIG. 1A, the left-right direction of the paper is the second direction (the direction orthogonal to the thickness direction and the first direction, the second direction in the surface direction), the left side of the paper is the second direction one side, and the right side of the paper is the second direction other side. is. Specifically, it conforms to the directional arrows in each figure.

<First Embodiment>
A film laminate 1, which is a first embodiment of the film laminate of the present invention, will be described below with reference to FIGS. 1 to 3. FIG.

1. Film Laminate As shown in FIGS. 1A and 1B, a film laminate 1 has a film shape (including a sheet shape) having a predetermined thickness. The film laminate 1 extends in plane directions (first direction and second direction) perpendicular to the vertical direction (thickness direction), and has a flat upper surface (surface on one side in the thickness direction) and a flat lower surface (surface on the other side in the thickness direction). surface). The film laminate 1 is, for example, one component for producing a base material for a touch panel provided in an image display device, and is not an image display device. That is, the film laminate 1 is a device that does not include an image display element such as an LCD module, is distributed as a component alone, and can be used industrially.

Specifically, the film laminate 1 includes a carrier film 2 and a conductive film 3 disposed thereon. That is, the film laminate 1 is a conductive film laminate, and includes a carrier film 2 and a conductive film 3 in order from the bottom. Preferably, film stack 1 consists of carrier film 2 and conductive film 3 . Each member will be described in detail below.

2. Carrier Film The carrier film 2 has a film shape with a predetermined thickness, extends in plane directions (first direction and second direction), and has a flat upper surface and a flat lower surface. The carrier film 2 is arranged on the lower side of the film laminate 1 , and more specifically, is arranged on the entire lower surface of the conductive film 3 so as to be in contact with the lower surface of the conductive film 3 .

The carrier film 2 can be attached to the conductive film 3 to be described later, and is a member for suppressing dimensional change of the conductive film 3 (that is, the patterned conductive film 12) when the conductive film 3 is heated. is. Also, it is a member for protecting the conductive film 3 from damage caused during transportation, heating and/or storage. The carrier film 2 supports the conductive film 3 from below.

Specifically, the carrier film 2 includes a protective substrate 4 and an adhesive layer 5 placed on the upper surface of the protective substrate 4 . That is, the carrier film 2 includes the protective substrate 4 and the adhesive layer 5 in order from the bottom. Preferably, carrier film 2 consists of protective substrate 4 and adhesive layer 5 .

(protective base material)
The protective base material 4 is a base material for suppressing dimensional change of the conductive film 3 . Further, it is a base material for securing the mechanical strength of the carrier film 2 and protecting the conductive film 3 from scratches that may occur during transportation, heating and/or storage.

The protective base material 4 has a film shape and is arranged in the lowermost layer of the carrier film 2 . That is, the protective base material 4 is a protective film, and is arranged in the bottom layer of the film laminate 1 .

The protective base material 4 has a thermal shrinkage rate of 0.20 in both the first direction (preferably the width direction described later: TD direction) and the second direction (preferably the width direction described later: TD direction). % or less. If the heat shrinkage rate is equal to or less than the above upper limit, dimensional change of the conductive film 3 can be suppressed.

Specifically, the heat shrinkage rate (A ₁ ) in the first direction and the heat shrinkage rate (A ₂ ) in the second direction are each 0.20% or less, preferably 0.15% or less, or more. It is preferably 0.10% or less, more preferably 0.05% or less, and is, for example, -0.10% or more, preferably 0.00% or more.

The thermal shrinkage rate of the protective base material 4 is the thermal shrinkage rate at room temperature (25°C) before and after heating to 145°C. The thermal shrinkage rate of the protective base material 4 can be measured, for example, as follows. The length at room temperature (25° C.) before heating of the object to be measured (protective base material 4 or the like) is measured as the length before heating. Subsequently, after heating the object to be measured at 145° C. for 60 minutes, the length when it is allowed to cool to room temperature (25° C.) is measured as the length after heating. Subsequently, it is calculated using the formula “thermal shrinkage rate (%)=(length before heating−length after heating)/(length before heating)×100”. Details will be described later in Examples.

The coefficient of linear thermal expansion (C ₁ ) in the first direction and the coefficient of linear thermal expansion (C ₂ ) in the second direction are each, for example, 60 ppm/° C. or more, preferably 70 ppm/° C. or more, and For example, it is 100 ppm/°C or less. If the coefficient of linear thermal expansion of the protective substrate 4 is at least the above lower limit, the difference in coefficient of linear thermal expansion between the carrier film 2 and the conductive film 3 can be reliably reduced, and the dimensional change of the conductive film 3 can be reduced. can be reliably suppressed.

The linear thermal expansion coefficient of the protective substrate 4 is between 25°C and 150°C. For example, the coefficient of linear thermal expansion is obtained by using a thermal analysis device to raise the temperature of the object to be measured (such as the protective base material 4) from 25°C to 150°C at a rate of 10°C/min. It can be obtained by measuring the average value of thermal expansion coefficients. Details will be described later in Examples.

The protective substrate 4 preferably includes a cycloolefin-based film and a polycarbonate-based film, and more preferably includes a cycloolefin-based film.

A cycloolefin film is formed from a cycloolefin resin.

A cycloolefin-based resin is obtained by polymerizing a cycloolefin monomer and is a polymer having an alicyclic structure in the repeating unit of the main chain.

Examples of cycloolefin-based resins include cycloolefin homopolymers composed of cycloolefin monomers, and cycloolefin copolymers composed of copolymers of cycloolefin monomers and olefins such as ethylene.

Cycloolefin monomers include polycyclic olefins such as norbornene, methylnorbornene, dimethylnorbornene, ethylidenenorbornene, butylnorbornene, dicyclopentadiene, dihydrodicyclopentadiene, tetracyclododecene, and tricyclopentadiene; monocyclic olefins such as cyclopentene, cyclooctadiene and cyclooctatriene; These cycloolefins can be used alone or in combination of two or more.

A polycarbonate-based film is formed from a polycarbonate-based resin.

A polycarbonate-based resin is a polymer having a carbonate bond (carbonic acid ester group: O--CO--O--) in the repeating unit of the main chain.

Polycarbonate-based resins include, for example, aromatic polycarbonates such as bisphenol A polycarbonate, and aliphatic polycarbonates such as poly(propylene carbonate).

The polycarbonate-based film may be formed from a polycarbonate-based resin mixture containing a polycarbonate-based resin and other resins (eg, polyolefin, ABS, polyester, etc.).

As a pretreatment, the protective base material 4 may or may not be heat-treated. Preferably, from the viewpoint of reducing the number of treatment steps and improving production efficiency, heat treatment as a pretreatment is unnecessary.

The thickness of the protective base material 4 is, for example, 10 μm or more, preferably 20 μm or more, and is, for example, 200 μm or less, preferably 150 μm or less, more preferably 80 μm or less. The thickness of the protective base material 4 can be measured, for example, with a microgauge thickness meter (manufactured by Mitutoyo Corporation).

(Adhesive layer)
The adhesive layer 5 is a layer (pressure-sensitive adhesive layer) for attaching the carrier film 2 to the conductive film 3, and is a layer that can be easily peeled off from the conductive film 3 after attachment. (easy peeling layer).

The pressure-sensitive adhesive layer 5 has a film shape and is arranged on the entire upper surface of the protective base material 4 so as to be in contact with the upper surface of the protective base material 4 . Specifically, the pressure-sensitive adhesive layer 5 is placed between the protective substrate 4 and the conductive film 3 between the upper surface of the protective substrate 4 and the lower surface of the conductive film 3 (specifically, the first hard coat layer 6 ). is arranged so as to contact the bottom surface of the Specifically, the adhesive layer 5 is pressure-sensitively adhered to the lower surface of the first hard coat layer 6 .

The adhesive layer 5 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, and polyamide adhesive compositions. , epoxy-based adhesive compositions, vinyl alkyl ether-based adhesive compositions, fluorine-based adhesive compositions, and the like. These adhesive compositions can be used alone or in combination of two or more.

As the pressure-sensitive adhesive composition, an acrylic pressure-sensitive adhesive composition is preferably used from the viewpoint of adhesiveness, releasability, and the like.

The acrylic pressure-sensitive adhesive composition contains, as a polymer component, for example, an acrylic polymer obtained by copolymerizing a monomer component containing a (meth)acrylic acid alkyl ester.

The weight-average molecular weight of the acrylic polymer is, for example, 1×10 ⁵ or more, preferably 3×10 ⁵ or more, and for example, 2×10 ⁶ or less, preferably from the viewpoint of adhesiveness, peelability, etc. is 1×10 ⁶ or less.

The pressure-sensitive adhesive composition can also appropriately contain known additives such as cross-linking agents, tackifier resins, processing aids, pigments, flame retardants, fillers, softeners, anti-aging agents, and the like.

The thickness of the adhesive layer 5 is, for example, 5 μm or more, preferably 10 μm or more, and is, for example, 50 μm or less, preferably 30 μm or less. The thickness of the adhesive layer 5 can be measured, for example, with a microgauge thickness meter (manufactured by Mitutoyo Corporation).

The thickness of the carrier film 2 is, for example, 100 μm or more, preferably 150 μm or more, and is, for example, 500 μm or less, preferably 250 μm or less.

3. Conductive Film The conductive film 3 has a film shape with a predetermined thickness, extends in the plane direction, and has a flat upper surface and a flat lower surface. The conductive film 3 is arranged on the upper side of the film laminate 1, and specifically, the entire upper surface of the carrier film 2 so as to be in contact with the upper surface of the carrier film 2 (specifically, the adhesive layer 5). , are placed.

The conductive film 3 is, for example, one component such as a base material for a touch panel provided in an image display device, that is, it is not an image display device. That is, the conductive film 3 is a component for producing an image display device or the like, does not include an image display element such as an LCD module, is distributed as a component alone, and is a device that can be used industrially.

The conductive film 3 includes a transparent substrate 7, a first hard coat layer 6 arranged on the lower surface of the transparent substrate 7, a second hard coat layer 8 arranged on the upper surface of the transparent substrate 7, and a second hard coat layer 8 arranged on the upper surface of the transparent substrate 7. An optical adjustment layer 9 arranged on the upper surface of the hard coat layer 8 and a transparent conductive layer 10 arranged on the upper surface of the optical adjustment layer 9 are provided. That is, the conductive film 3 is a transparent conductive film and includes a first hard coat layer 6, a transparent substrate 7, a second hard coat layer 8, an optical adjustment layer 9 and a transparent conductive layer 10 in this order from the bottom. Preferably, the conductive film 3 comprises a first hard coat layer 6, a transparent substrate 7, a second hard coat layer 8, an optical adjustment layer 9 and a transparent conductive layer 10.

(First hard coat layer)
The first hard coat layer 6 is a scratch protection layer for making the conductive film 3 less likely to be scratched. In addition, the first hard coat layer 6 is also an anti-blocking layer for imparting blocking resistance to the surfaces of the plurality of conductive films 3 in contact with each other when, for example, a plurality of film laminates 1 are stacked vertically. be.

The first hard coat layer 6 has a film shape and is arranged on the entire upper surface of the adhesive layer 5 so as to be in contact with the upper surface of the adhesive layer 5 . Specifically, the first hard coat layer 6 is arranged between the adhesive layer 5 and the transparent substrate 7 so as to contact the upper surface of the adhesive layer 5 and the lower surface of the transparent substrate 7 . . Also, the first hard coat layer 6 is arranged as the bottom layer of the conductive film 3 .

The first hard coat layer 6 is a cured resin layer made of a hard coat composition.

The hard coat composition of the first hard coat layer 6 contains a resin, preferably a resin and particles.

Examples of resins include curable resins and thermoplastic resins (eg, polyolefin resins), and preferably curable resins.

Examples of curable resins include active energy ray-curable resins that are cured by irradiation with active energy rays (specifically, ultraviolet rays, electron beams, etc.), and thermosetting resins that are cured by heating. Active energy ray-curable resins are preferred.

Active energy ray-curable resins include, for example, polymers having functional groups having polymerizable carbon-carbon double bonds in the molecule. Examples of such functional groups include vinyl groups, (meth)acryloyl groups (methacryloyl groups and/or acryloyl groups), and the like.

Specific examples of active energy ray-curable resins include (meth)acrylic UV-curable resins such as urethane acrylate and epoxy acrylate.

Examples of curable resins other than active energy ray-curable resins include thermosetting resins such as urethane resins, melamine resins, alkyd resins, siloxane-based polymers, and organic silane condensates.

These resins can be used singly or in combination of two or more.

Examples of particles include inorganic particles and organic particles. Examples of inorganic particles include silica particles, metal oxide particles such as zirconium oxide, titanium oxide, zinc oxide and tin oxide, and carbonate particles such as calcium carbonate. Examples of organic particles include crosslinked acrylic resin particles. The particles can be used singly or in combination of two or more.

From the viewpoint of transparency, the particles are preferably organic particles, more preferably crosslinked acrylic resin particles.

The content of the particles is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass, with respect to 100 parts by mass of the resin. It is below.

The thickness of the first hard coat layer 6 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and is, for example, 10 μm or less, preferably 5 μm or less. When the thickness of the first hard coat layer 6 is within the above range, the scratch resistance and blocking resistance are excellent. The thickness of each hard coat layer can be measured, for example, with a spectroscopic ellipsometer.

(Transparent substrate)
The transparent base material 7 is a transparent base material for ensuring mechanical strength of the conductive film 3 . That is, the transparent base material 7 supports the transparent conductive layer 10 together with the first hard coat layer 6 and the second hard coat layer 8 .

The transparent base material 7 has a film shape and is arranged on the entire upper surface of the first hard coat layer 6 so as to be in contact with the upper surface of the first hard coat layer 6 . Specifically, the transparent substrate 7 is placed between the first hard coat layer 6 and the second hard coat layer 8 so as to be in contact with the upper surface of the first hard coat layer 6 and the lower surface of the second hard coat layer 8 . is located in

The transparent substrate 7 is preferably a cycloolefin film. As a result, the in-plane retardation of the conductive film 3 can be reduced, and the transparency is excellent.

A cycloolefin film is formed from a cycloolefin resin. As the material of the cycloolefin-based resin, the same materials as those of the cycloolefin-based resin described above for the protective base material 4 can be used.

The total light transmittance (JIS K 7375-2008) of the transparent substrate 7 is, for example, 80% or more, preferably 85% or more.

The thickness of the transparent substrate 7 is less than 20 μm, preferably 15 μm or less, and is, for example, 1 μm or more, preferably 5 μm or more. If the thickness of the transparent substrate 7 is equal to or less than the above upper limit, the thickness of the conductive film 3 can be reduced and the transparency is excellent. Moreover, if the thickness of the transparent base material 7 is more than the said minimum, it will be excellent in mechanical strength.

The thickness of the transparent substrate 7 can be measured using, for example, a microgauge thickness meter (manufactured by Mitutoyo Corporation).

(Second hard coat layer)
The second hard coat layer 8 is a scratch protection layer for making the conductive film 3 less likely to be scratched.

The second hard coat layer 8 has a film shape and is arranged on the entire upper surface of the transparent base material 7 so as to be in contact with the upper surface of the transparent base material 7 . Specifically, the second hard coat layer 8 is arranged between the transparent base material 7 and the optical adjustment layer 9 so as to be in contact with the upper surface of the transparent base material 7 and the lower surface of the optical adjustment layer 9 . .

The second hard coat layer 8 is a layer similar to the first hard coat layer 6, and for example, the same layer as described above for the first hard coat layer 6 can be used.

Preferably, the hard coat composition of the second hard coat layer 8 contains a resin, preferably a resin and particles.

Examples of the resin and particles include those similar to those of the hard coat composition described above.

From the viewpoint of scratch resistance, the thickness of the second hard coat layer 8 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and is, for example, 10 μm or less, preferably 5 μm or less.

(Optical adjustment layer)
The optical adjustment layer 9 adjusts the optical physical properties (e.g., refractive index) of the conductive film 3 in order to ensure excellent transparency of the conductive film 3 while suppressing the visibility of the pattern in the transparent conductive layer 10. layer.

The optical adjustment layer 9 has a film shape and is arranged on the entire upper surface of the second hard coat layer 8 so as to be in contact with the upper surface of the second hard coat layer 8 . Specifically, the optical adjustment layer 9 is arranged between the second hard coat layer 8 and the transparent conductive layer 10 so as to be in contact with the upper surface of the second hard coat layer 8 and the lower surface of the transparent conductive layer 10 . ing.

The optical adjustment layer 9 is formed from an optical adjustment composition.

The optical adjustment composition contains a resin, preferably a resin and particles.

Examples of resins include the same resins as those used in the hard coat composition. A curable resin is preferred, and an active energy ray-curable resin is more preferred.

The resin content in the optical adjustment composition is, for example, 10% by mass or more, preferably 25% by mass or more, and is, for example, 95% by mass or less, preferably 60% by mass or less.

As the particles, a suitable material can be selected according to the refractive index required for the optical adjustment layer 9, and examples thereof include inorganic particles and organic particles. Examples of inorganic particles include silica particles, metal oxide particles such as zirconium oxide, titanium oxide, zinc oxide and tin oxide, and carbonate particles such as calcium carbonate. Examples of organic particles include crosslinked acrylic resin particles. The particles can be used singly or in combination of two or more.

The particles preferably include inorganic particles, more preferably metal oxide particles, and still more preferably zirconium oxide particles.

The content of the particles is, for example, 5% by mass or more, preferably 40% by mass or more, and is, for example, 90% by mass or less, preferably 75% by mass or less, relative to the optical adjustment composition. .

The refractive index of the optical adjustment layer 9 is, for example, 1.50 or more, preferably 1.60 or more, and is, for example, 1.80 or less, preferably 1.75 or less. The refractive index can be measured, for example, with an Abbe refractometer.

The thickness of the optical adjustment layer 9 is, for example, 50 nm or more, preferably 100 nm or more, and is, for example, 800 nm or less, preferably 300 nm or less. The thickness of the optical adjustment layer 9 can be measured by, for example, a spectroscopic ellipsometer.

(Transparent conductive layer)
The transparent conductive layer 10 is a transparent conductive layer for forming a desired pattern such as an electrode pattern or a wiring pattern in a post-process such as etching.

The transparent conductive layer 10 has a film shape and is arranged on the uppermost layer of the conductive film 3 . That is, the transparent conductive layer 10 is arranged as the uppermost layer of the film laminate 1 . Specifically, the transparent conductive layer 10 is arranged on the entire upper surface of the optical adjustment layer 9 so as to be in contact with the upper surface of the optical adjustment layer 9 .

At least one selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W as the material of the transparent conductive layer 10, for example. metal oxides containing metals of The metal oxide may be further doped with a metal atom shown in the above group, if necessary.

The material of the transparent conductive layer 10 preferably includes indium-containing oxides such as indium-tin composite oxide (ITO), antimony-containing oxides such as antimony-tin composite oxide (ATO), and more. Indium-containing oxides are preferred, and ITO is more preferred. If the material of the transparent conductive layer 10 is ITO, the transparent conductive layer 10 can achieve both excellent transparency and conductivity.

When ITO is used as the material of the transparent conductive layer 10, the tin oxide (SnO ₂ ) content is preferably, for example, 0.5% by mass or more with respect to the total amount of tin oxide and indium oxide (In ₂ O ₃ ). is 5% by mass or more, and is, for example, 50% by mass or less, preferably 35% by mass or less.

"ITO" may be 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, and specific examples include Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, and Fe. , Pb, Ni, Nb, Cr, Ga, and the like.

The thickness of the transparent conductive layer 10 is, for example, 10 nm or more, preferably 20 nm or more, and is, for example, 100 nm or less, preferably 35 nm or less. The thickness of the transparent conductive layer 10 can be measured by, for example, a spectroscopic ellipsometer.

The transparent conductive layer 10 may be either crystalline or amorphous. In the present invention, the transparent conductive layer 10 is preferably amorphous, specifically an amorphous ITO layer. is. In the present invention, preferably, when the amorphous patterned transparent conductive layer 11 (described later) is heated to convert it into a crystalline patterned transparent conductive layer 16 (described later), the patterned transparent conductive layer 11 undergoes a dimensional change, In particular, pattern deformation can be suppressed.

To determine whether the transparent conductive layer 10 is crystalline or amorphous, for example, when the transparent conductive layer 10 is an ITO layer, it is immersed in hydrochloric acid (concentration: 5% by mass) at 20° C. for 15 minutes, then washed with water and dried. It can be judged by measuring the resistance between terminals for about 15 mm. After immersion in hydrochloric acid (20° C., concentration 5% by mass), washing with water, and drying, the ITO layer is defined as crystalline when the resistance between the terminals for 15 mm is 10 kΩ or less. On the other hand, if the inter-terminal resistance for 15 mm exceeds 10 kΩ, the ITO layer is amorphous.

The thickness of the conductive film 3 is, for example, 10 μm or more, preferably 25 μm or more, and is, for example, 200 μm or less, preferably 150 μm or less.

The total light transmittance (JIS K 7375-2008) of the conductive film 3 is, for example, 80% or more, preferably 85% or more.

The heat shrinkage rate of the conductive film 3 is preferably 0.60% or less. If the heat shrinkage rate is equal to or less than the upper limit, dimensional change of the conductive film 3 after pattern formation (that is, the patterned transparent conductive film 12) can be further suppressed.

Specifically, the thermal contraction rate (B ₁ ) in the first direction and the thermal contraction rate (B ₂ ) in the second direction are each preferably 0.60% or less, more preferably 0.30. % or less, more preferably 0.05% or less, and for example -0.10% or more, preferably 0.00% or more.

The thermal shrinkage rate of the conductive film 3 is the thermal shrinkage rate at room temperature (25°C) before and after heating to 145°C. can.

The linear thermal expansion coefficient (D ₁ ) in the first direction and the linear thermal expansion coefficient (D ₂ ) in the second direction are each, for example, 60 ppm/° C. or higher, preferably 80 ppm/° C. or higher, and For example, it is 150 ppm/°C or less. In the film laminate 1, the dimensional change of the conductive film 3 having such a high coefficient of linear thermal expansion can be suppressed.

The linear thermal expansion coefficient of the conductive film 3 is between 25° C. and 150° C., for example. The coefficient of linear thermal expansion can be measured, for example, in the same manner as the coefficient of linear thermal expansion of the protective base material 4 described above.

4. Method for producing film laminate The method for producing the film laminate 1 (preparation step) includes, for example, a step of producing a carrier film 2, a step of producing a conductive film 3, and affixing the carrier film 2 and the conductive film 3. and a step of wearing. The method for manufacturing the film laminate 1 is preferably carried out by a roll-to-roll method.

(Preparation of carrier film)
To produce the carrier film 2, first, a protective base material 4 is prepared. For example, in the case of the roll-to-roll method, a protective base material 4 that is long in the transport direction (MD direction) and wound into a roll is used. In this case, the transport direction is defined as the first direction, and the width direction (TD direction, orthogonal direction) perpendicular to the transport direction is defined as the second direction (see the left diagram in FIG. 2).

Next, the pressure-sensitive adhesive layer 5 is provided on the upper surface of the protective base material 4 by a roll-to-roll method. In order to provide the adhesive layer 5 , an adhesive layer transfer film is prepared and the adhesive layer 5 is transferred to the protective base material 4 . Alternatively, the adhesive composition is applied to the upper surface of the protective base material 4 and dried.

Thereby, the carrier film 2 having the protective substrate 4 and the adhesive layer 5 is obtained.

(Preparation of conductive film)
To produce the conductive film 3, first, a transparent substrate 7 is prepared. For example, in the case of the roll-to-roll method, a transparent substrate 7 that is long in the transport direction and wound into a roll is used.

Next, hard coat layers (first hard coat layer 6 and second hard coat layer 8) are provided on both surfaces of the transparent base material 7 . For example, a diluted solution is prepared by diluting the hard coat composition with a solvent, the diluted solution is applied to the lower surface and the upper surface of the transparent substrate 7, the diluted solution is dried, and the hard coat composition is cured as necessary. Let As a result, the first hard coat layer 6 is formed on the lower surface of the transparent substrate 7 and the second hard coat layer 8 is formed on the upper surface of the transparent substrate 7 .

Next, an optical adjustment layer 9 is provided on the upper surface of the second hard coat layer 8 . For example, a diluted solution is prepared by diluting the optical adjustment composition with a solvent, the diluted solution of the optical adjustment composition is applied to the upper surface of the second hard coat layer 8, the diluted solution is dried, and the optical adjustment composition is dried. Allow the composition to cure. Thereby, the optical adjustment layer 9 is formed on the upper surface of the second hard coat layer 8 .

Next, a transparent conductive layer 10 is provided on the top surface of the optical adjustment layer 9 . For example, the transparent conductive layer 10 is formed on the upper surface of the optical adjustment layer 9 by a dry method.

Dry methods include, for example, a vacuum deposition method, a sputtering method, an ion plating method, and the like. Sputtering is preferred. A thin transparent conductive layer 10 can be formed by this method.

Thereby, the conductive film 3 having the first hard coat layer 6, the transparent substrate 7, the second hard coat layer 8, the optical adjustment layer 9 and the transparent conductive layer 10 in this order is obtained. The transparent conductive layer 10 of the conductive film 3 is a non-patterned transparent conductive layer, preferably amorphous.

(stick)
To attach the carrier film 2 and the conductive film 3 , the top surface of the carrier film 2 is brought into contact with the bottom surface of the conductive film 3 .

Specifically, the conductive film 3 is arranged on the carrier film 2 so that the first hard coat layer 6 is in contact with the adhesive layer 5 . That is, the protective base material 4 is pressure-sensitively adhered to the conductive film 3 via the adhesive layer 5 .

Thereby, the film laminate 1 having the carrier film 2 and the conductive film 3 in this order is obtained. The transparent conductive layer 10 of the film laminate 1 is a non-patterned transparent conductive layer, preferably amorphous. For example, in the case of the roll-to-roll method, the film laminate 1 is obtained as a rolled body, as shown in the right diagram of FIG.

In addition, the film laminate 1 can also be manufactured by a batch method (sheet-fed method). , is obtained (see FIG. 1B).

5. Film Laminate In the film laminate 1, the difference between the linear thermal expansion coefficient of the protective substrate 4 and the linear thermal expansion coefficient of the conductive film 3, that is, the linear thermal expansion coefficient difference is 40 ppm/°C or less. If the linear thermal expansion coefficient difference is equal to or less than the upper limit, dimensional change of the conductive film 3 after pattern formation can be suppressed.

Specifically, the linear thermal expansion coefficient difference in the first direction (the absolute value of D ₁ −C ₁ ) and the linear thermal expansion coefficient difference in the second direction (the absolute value of D ₂ −C ₂ ) are, respectively, It is 40 ppm/°C or less, preferably 20 ppm/°C or less, more preferably 15 ppm/°C or less, still more preferably 13 ppm/°C or less, and 0 ppm/°C or more.

Further, when the film laminate 1 is heated and peeled, the heat shrinkage ratio of the conductive film 3 after heat peeling with respect to the conductive film 3 before heat peeling (that is, the film laminate 1 before heat peeling) is preferably is 0.20% or less. Thereby, the dimensional change of the conductive film 3 after pattern formation can be reduced more reliably.

Specifically, the heat shrinkage rate in the first direction and the heat shrinkage rate in the second direction are preferably 0.20% or less, more preferably 0.10% or less, and still more preferably 0. 0.05% or less, or, for example, −0.10% or more, preferably 0.00% or more.

The thermal shrinkage rate of the film laminate 1 before and after the heat peeling can be measured, for example, as follows. First, the film laminate 1 is cut into a predetermined size, and the length at room temperature (25° C.) is measured as the length before heating. Subsequently, after the film laminate 1 is heated, it is allowed to cool to room temperature (25° C.), and the length of the conductive film 3 when the carrier film 2 is peeled off is measured as the length after heating. Subsequently, it is calculated using the formula “thermal shrinkage rate (%)=(length before heating−length after heating)/(length before heating)×100”. Details will be described later in Examples.

The heating conditions for the film laminate 1 are not limited, and are appropriately determined according to the crystallization temperature of the transparent conductive layer 10 such as ITO and the curing temperature of the binder resin contained in the metal nanowire layer, which will be described later. Specifically, the temperature is, for example, 100° C. or higher, preferably 120° C. or higher, and is, for example, 200° C. or lower, preferably 160° C. or lower. The time is, for example, 1 minute or more, preferably 30 minutes or more, and is, for example, 120 minutes or less, preferably 90 minutes or less.

According to this film laminate 1, since the transparent substrate 7 of the conductive film 3 has a thickness of less than 20 μm, the conductive film 3 can be made very thin. In addition, even though the conductive film 3 is ultra-thin, it is possible to suppress the dimensional change of the conductive film 3 after patterning. That is, as will be described later, even when the transparent conductive layer 10 is heated and the carrier film 2 is peeled off after etching the conductive film 3 in a desired pattern in the state of the film laminate 1, the The heated patterned conductive film 14 can maintain the desired pattern. Accordingly, the heated patterned conductive film 14 having the desired pattern can be incorporated into an image display device.

6. Application of Film Laminate The film laminate 1 is used, for example, as a substrate for a touch panel provided in an image display device. Specifically, for the film laminate 1, as shown in FIGS. 3A to 3D, for example, a preparation step, a patterning step, a heating step, and a peeling step are sequentially performed. The heated patterned conductive film 14 obtained by these steps is used as a substrate for a touch panel. Each step will be described in detail below.

(Preparation process)
In the preparation step, as shown in FIG. 3A, the film laminate 1 is prepared by, for example, the manufacturing method described above.

(Patterning process)
In the patterning step, the transparent conductive layer 10 is patterned as shown in FIG. 3B.

Specifically, the transparent conductive layer 10 is etched by a known etching method so as to form a desired pattern (for example, an electrode pattern or a wiring pattern in the touch input area).

Thereby, the patterned transparent conductive layer 11 is formed from the transparent conductive layer 10 .

As a result, patterned film laminate 13 comprising carrier film 2 and patterned conductive film 12 is obtained.

(Heating process)
In the heating step, as shown in FIG. 3C, the patterning film laminate 13 is heated.

Specifically, for example, the patterning film laminate 13 is heated in the atmosphere.

Heat treatment can be performed using, for example, an infrared heater, an oven, or the like.

The heating temperature is, for example, 100° C. or higher, preferably 120° C. or higher, and is, for example, 200° C. or lower, preferably 160° C. or lower.

The heating time is, for example, 10 minutes or more, preferably 30 minutes or more, and is, for example, 5 hours or less, preferably 3 hours or less.

At this time, preferably, tension is not applied in the planar direction of the patterning film laminate 13 .

A heated patterned film laminate 15 comprising the carrier film 2 and the heated patterned conductive film 14 is thereby obtained.

In the heated patterned conductive film 14 , the patterned transparent conductive layer 11 is crystallized to form a crystalline patterned transparent conductive layer 16 . Thereby, the resistance value of the transparent conductive layer can be reduced, and the conductivity is excellent.

(Peeling process)
In the peeling step, the carrier film 2 is peeled (removed) from the heated patterned film laminate 13 as shown in the phantom line of FIG. 3C and FIG. 3D.

Specifically, the carrier film 2 is removed from the heated patterned film laminate 13 so that the upper surface of the adhesive layer 5 and the lower surface of the first hard coat layer 6 are separated from each other.

This results in a heated patterned conductive layer comprising, in order, a first hard coat layer 6, a transparent substrate 7, a second hard coat layer 8, an optical adjustment layer 9, and a crystalline patterned transparent conductive layer 16, as shown in FIG. 3D. A flexible film 14 is obtained alone.

The heating step and the peeling step may be performed by a roll-to-roll method or by a batch method.

The heated patterned conductive film 14 is used, for example, as a substrate for a touch panel. Examples of the type of touch panel include various types such as a capacitive type and a resistive film type, and it is particularly preferably used for a capacitive type touch panel.

In this heated patterned conductive film 14, the pattern of the patterned transparent conductive layer 11 of the film laminate 1 before heating and the patterned conductive layer 11 after heating, although the transparent substrate 7 is ultra-thin with a thickness of less than 20 μm. The dimensional change of the crystalline patterned transparent conductive layer 16 of the film 14 and the pattern of the transparent conductive layer 16 are small. Therefore, in the heated patterned conductive film 14, a desired pattern similar to that at the beginning of patterning can be maintained.

7. MODIFIED EXAMPLE In the modified example, the same reference numerals are given to the same members as in the above-described one embodiment, and detailed description thereof will be omitted.

(1) In one embodiment shown in FIG. 1A, the transparent conductive layer 10 is a transparent conductive layer made of a metal oxide. For example, although not shown, the transparent conductive layer 10 is a metal nanowire layer (metal mesh layer). including).

The metal nanowire layer contains metal nanowires and a binder resin.

A metal nanowire is a needle-like or thread-like metal with a diameter of nanometer size (preferably less than 500 nm). The metal constituting the metal nanowires preferably includes conductive metals such as Au, Ag, Cu, and Ni, and from the viewpoint of conductivity, Au is preferable.

The binder resin is not limited as long as it is a resin for fixing metal nano-nanowires, and preferably includes curable resins such as thermosetting resins and ultraviolet curable resins. Such binder resins and proportions are described, for example, in JP-A-2017-183195.

(2) In one embodiment shown in FIG. 1A, the conductive film 3 includes a first hard coat layer 6, a second hard coat layer 8 and an optical adjustment layer 9. For example, although not shown, a conductive The film 3 may not include at least one of the first hard coat layer 6, the second hard coat layer 8, and the optical adjustment layer 9, or all of them.

Further, for example, although not shown, the conductive film 3 may further include at least one layer of the optical adjustment layer 9 and the transparent conductive layer 10 on its lower surface.

<Second embodiment>
A film laminate 1, which is a second embodiment of the film laminate of the present invention, will be described below with reference to FIGS. 4 and 5. FIG. In addition, in 2nd Embodiment, the same code|symbol is attached|subjected to the member similar to above-described 1st Embodiment, and the description is abbreviate|omitted. Also, the modified example of the first embodiment can be applied to the second embodiment as well. Moreover, the second embodiment can achieve the same effects as those of the first embodiment, unless otherwise specified.

As shown in FIG. 4, the film laminate 1 of the second embodiment includes a carrier film 2 and a conductive film 3 arranged on the upper surface thereof.

The conductive film 3 of the second embodiment further comprises a metal layer 17 arranged on the top surface of the transparent conductive layer 10 . Specifically, in the conductive film 3 of the second embodiment, the first hard coat layer 6, the transparent substrate 7, the second hard coat layer 8, the optical adjustment layer 9, the transparent conductive layer 10 and the metal layer 17 are placed downward. Prepare in order from That is, the conductive film 3 of the second embodiment is a conductive film with a metal layer including a transparent conductive film and a metal layer 17 .

The metal layer 17 is formed in a desired pattern in a post-process, for example, to form a wiring pattern (for example, routing wiring) on the outer edge (peripheral edge) of the touch input area of the touch panel. It is a conductive metal layer.

The metal layer 17 has a film shape and is arranged on the uppermost layer of the conductive film 3 . That is, the metal layer 17 is arranged as the uppermost layer of the film laminate 1 . Specifically, the metal layer 17 is arranged on the entire upper surface of the transparent conductive layer 10 so as to be in contact with the upper surface of the transparent conductive layer 10 .

Examples of materials for the metal layer 17 include metals such as copper, nickel, chromium, iron, titanium, or alloys thereof. Copper is preferred from the viewpoint of conductivity and the like.

If the metal layer 17 is made of a material such as copper that is easily oxidized, the surface of the metal layer 17 may be oxidized. Specifically, when the metal layer 17 is a copper layer, the metal layer 17 may be a copper layer having copper oxide on part or all of the surface.

The thickness of the metal layer 17 is, for example, 100 nm or more, preferably 150 nm or more, and is, for example, 400 nm or less, preferably 300 nm or less.

A metal layer 17 is formed on the upper surface of the transparent conductive layer 10 by, for example, a dry method.

Dry methods include, for example, a vacuum deposition method, a sputtering method, an ion plating method, and the like. Sputtering is preferred. A thin metal layer 17 can be formed by this method.

Similarly to the first embodiment, the film laminate 1 of the second embodiment is also used, for example, as a base material for a touch panel provided in an image display device. Preferably, it is used for a substrate for a touch panel with a metal wiring layer.

Specifically, for the film laminate 1, as shown in FIGS. 5A to 5D, for example, a preparation step, a patterning step, a heating step, and a peeling step are sequentially performed.

In the patterning step, as shown in FIG. 5B, the metal layer 17 and the transparent conductive layer 10 are patterned in this order.

In the patterning of the metal layer 17, the metal layer (particularly, the planar Central portion in view) is etched by a known etching method.

Thereby, the patterned metal layer 18 is formed from the metal layer 17 .

Next, the transparent conductive layer 10 is patterned in the same manner as in the first embodiment. For example, the transparent conductive layer 10 exposed from the patterned metal layer 18 (particularly, the central portion in plan view) is etched into a desired pattern.

As shown in FIGS. 5C-D, the heating process and peeling process are the same as in the first embodiment.

As a result, as shown in FIG. 5D, a conductive layer comprising a first hard coat layer 6, a transparent substrate 7, a second hard coat layer 8, an optical adjustment layer 9, a crystalline patterned transparent conductive layer 16 and a patterned metal layer 18 in order. A conductive film (heated patterned conductive film 14) is obtained alone.

EXAMPLES Examples and comparative examples are shown below to describe the present invention more specifically. It should be noted that the present invention is by no means limited to Examples and Comparative Examples. Specific numerical values such as the mixing ratio (content ratio), physical property values, and parameters used in the following description are described in the above "Mode for Carrying Out the Invention", the corresponding mixing ratio (content ratio ), physical property values, parameters, etc. can.

<Example 1>
(Preparation of conductive film)
A conductive film was produced by a roll-to-roll method as follows.

A cycloolefin film (COP film, 18 μm thick, manufactured by Konica Minolta, “SANUQI”) elongated in the MD direction (conveyance direction: first direction) was prepared as a transparent substrate.

A diluted solution of a hard coat composition containing a binder resin and a plurality of particles is applied to the lower surface of a transparent substrate, and a diluted solution of a hard coat composition comprising a binder resin is applied to the upper surface of the transparent substrate. After drying, both surfaces were irradiated with ultraviolet rays to cure the hard coat composition. As a result, a first hard coat layer (1.0 μm thick, particle-containing resin layer) is formed on the lower surface of the transparent substrate, and a second hard coat layer (1.0 μm thick, particle-containing resin layer) is formed on the upper surface of the transparent substrate. resin layer) was formed.

Next, on the upper surface of the second hard coat layer, a diluted solution of an optical adjustment composition containing zirconia particles and an ultraviolet curable resin ("OPSTAR Z7412" manufactured by JSR Corporation, refractive index 1.64) is applied, After drying, it was irradiated with ultraviolet rays. As a result, an optical adjustment layer (thickness: 0.1 μm) was formed on the upper surface of the second hard coat layer.

Next, a sintered body target containing indium oxide and tin oxide was used to form a transparent conductive layer (amorphous ITO layer, thickness 25 μm) on the upper surface of the optical adjustment layer by a sputtering method.

As a result, a conductive film was produced, which includes the first hard coat layer, the transparent substrate, the second hard coat layer, the optical adjustment layer, and the transparent conductive layer in this order.

(Preparation of carrier film)
A carrier film was manufactured by a roll-to-roll method as follows.

100 parts by mass of butyl acrylate and 6 parts by mass of acrylic acid were copolymerized by solution polymerization to obtain an acrylic copolymer having a weight average molecular weight of 600,000. An acrylic pressure-sensitive adhesive was obtained by adding 6 parts by mass of an epoxy-based cross-linking agent (“Tetrad C”, manufactured by Mitsubishi Gas Chemical Co., Ltd.) to 100 parts by mass (solid content) of the acrylic copolymer. The acrylic pressure-sensitive adhesive was applied to a release film (release-treated polyethylene terephthalate film) and dried to form an acrylic pressure-sensitive adhesive layer (adhesive layer) having a thickness of 20 μm. Thus, an adhesive layer transfer film was obtained.

Next, a cycloolefin film (COP film, thickness 40 μm, “ZEONOR” manufactured by Nippon Zeon Co., Ltd.) elongated in the MD direction was prepared as a protective substrate. The acrylic pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer transfer film was adhered to this protective substrate, and the release film was peeled off.

Thus, a carrier film having a protective substrate and an acrylic pressure-sensitive adhesive layer was produced.

(Production of film laminate)
A conductive film and a carrier film were adhered so that the first hard coat layer and the pressure-sensitive adhesive layer were in contact with each other to produce a film laminate of the example.

<Examples 2 to 4>
A film laminate of Example was obtained in the same manner as in Example 1, except that the configurations of each protective substrate and each conductive film were changed to those shown in Table 1. In the table, COP indicates cycloolefin resin, PC indicates polycarbonate resin, and PET indicates polyethylene terephthalate resin.

In addition, in Example 2 and Example 4, the produced conductive film was heat-treated at 150° C. for 30 minutes without tension.

<Comparative Examples 1 to 4 >
A film laminate of a comparative example was obtained in the same manner as in Example 1, except that the configurations of each protective substrate and each conductive film were changed to those shown in Table 1.

In Comparative Examples 3 and 4, the prepared protective substrate (PET film) was subjected to heat treatment at 150° C. for 30 minutes without tension.

<Measurement of thickness>
The thicknesses of the protective base material and the transparent base material used in each example and each comparative example were measured with a microgauge thickness meter (manufactured by Mitutoyo Corporation).

<Measurement of linear thermal expansion coefficient>
(1) Protective substrate The linear thermal expansion coefficients in the MD direction and the TD direction (width direction) at 25°C to 150°C were measured for the protective substrates prepared in each example and each comparative example.

Specifically, each protective base material was cut into strips and used as measurement samples. At this time, the size of the sample was 20 mm in the MD direction×4 mm in the TD direction in the measurement in the MD direction, and the size of the sample in the measurement in the TD direction was 20 mm in the TD direction×4 mm in the MD direction.

Then, using a thermal analysis apparatus (TMA), measure the dimensional change rate with respect to temperature change (between 25 ° C. and 150 ° C.) of the measurement sample in the MD direction or TD direction under the following conditions. ₁ and _C2 were calculated. Table 1 shows the results.

Thermal analysis device: "TMA Q-400" manufactured by TA Instruments
Measurement mode: Tensile mode Span between chucks: 16 mm
Atmospheric gas: N ₂ (50 ml/min)
Measurement load: 19.6mN
Temperature conditions: 25-150°C
Heating rate: 10°C/min
Pre-measurement treatment: Heat treatment (distortion removal treatment) at 150 ° C. for 30 minutes before measurement (2) Conductive film The conductive films produced in each example and each comparative example were also treated in the same manner as the above protective substrate. , the linear thermal expansion coefficients D ₁ and D ₂ in the MD and TD directions at 25° C.-150° C. were measured. Table 1 shows the results.

(3) Linear thermal expansion coefficient difference In each of the MD direction and the TD direction, the linear thermal expansion coefficient of the protective substrate is subtracted from the linear thermal expansion coefficient of the conductive film, and the difference (D ₁ - C _1, or D ₂ -C ₂ ) was calculated. The higher value in the MD direction and the TD direction was taken as the linear thermal expansion coefficient difference. Table 1 shows the results.

<Measurement of heat shrinkage>
(1) Protective base The protective base prepared in each example and each comparative example was cut into a substantially square shape of 100 mm in the MD direction × 100 mm in the TD direction (see Fig. 2), and each of the four corners was crossed. A test piece was prepared by scratching the pattern. In the test piece (25 ° C.) before heating, the distance (length) between the MD directions of the scratches (cross pattern center) and the distance (length) between the TD directions were measured with a CNC three-dimensional measuring machine (Mitutoyo Co., Ltd.) Measured at room temperature (25° C.) using “LEGEX774” manufactured by Thereby, the length before heating was obtained in each of the MD direction and the TD direction.

Then, the test piece was placed on a horizontal table in an oven, heated at 145° C. for 60 minutes, and then allowed to cool at room temperature (25° C.) for 1 hour. After that, the distance between the scratches in the MD direction and the distance between the scratches in the TD direction were measured with a CNC three-dimensional measuring machine. Thereby, the length after heating was obtained in each of the MD direction and the TD direction. Next, thermal contraction rates A ₁ and A ₂ were calculated in the MD direction and the TD direction, respectively, using the following equations. Table 1 shows the results.

Thermal shrinkage rate (%) = [length before heating (mm) - length after heating (mm)] / length before heating (mm) x 100
(2) Conductive Film The heat shrinkage rates _B1 and _B2 of the conductive films produced in each example and each comparative example were calculated in the same manner as for the protective substrate. Table 1 shows the results.

<Heat shrinkage rate before and after heat peeling of film laminate>
The film laminate of each example and each comparative example was cut into a substantially square shape of 100 mm in the MD direction×100 mm in the TD direction in plan view, and each of the four corners was scratched in a cross pattern to prepare a test piece. In the test piece (25 ° C.) before heating, the distance (length) between the MD directions of the scratches (cross pattern center) and the distance (length) between the TD directions were measured with a CNC three-dimensional measuring machine (Mitutoyo Co., Ltd.) Measured at room temperature (25° C.) using “LEGEX774” manufactured by Thereby, the length of the film laminate (that is, the length of the conductive film before heat peeling) was obtained in each of the MD and TD directions.

Next, each film laminate was heated under conditions of no tension at 145° C. for 60 minutes, then cooled at room temperature for 60 minutes, and then the carrier film was peeled off. As a result, a conductive film after heat peeling was obtained. In this film, the distance between the scratches in the MD direction and the distance between the scratches in the TD direction were measured using a CNC three-dimensional measuring machine. Thereby, the length of the conductive film after heat peeling was obtained in each of the MD direction and the TD direction.

Then, the thermal shrinkage rate was calculated in each of the MD direction and the TD direction according to the following formula. Length of conductive film after (mm)] ÷ Length of conductive film before heat peeling (mm) × 100
Table 1 shows the results.

<Dimensional change of patterned conductive film>
The film laminate of each example and each comparative example was cut into a substantially square shape in plan view of 100 mm in the MD direction×100 mm in the TD direction, and the transparent conductive layer was etched into a striped pattern with a width of 10 mm in the MD direction and an interval of 10 mm. (See Figure 6).

The dimensional change rate of the patterning film laminate before and after the heat treatment was measured at three locations shown in FIG. A case where the concentration was less than 0.20% in all three locations was evaluated as ◯, and a case where even one location was 0.20% or more was evaluated as x. Table 1 shows the results.

1 film laminate 2 carrier film 3 conductive film 4 protective substrate 7 transparent substrate 10 transparent conductive layer 14 heated patterned conductive film 17 metal layer

Claims (4)

A film laminate comprising a carrier film and a conductive film in the thickness direction,
The conductive film includes a transparent substrate and a conductive layer in the thickness direction,
The carrier film comprises a protective substrate,
The transparent substrate is a cycloolefin film,
The thickness of the transparent base material is less than 20 μm,
The thermal shrinkage rate of the protective base material when heated at 145° C. for 60 minutes is 0.15% or less in both the first direction and the second direction ,
A film laminate, wherein the linear thermal expansion coefficient difference between the protective substrate and the conductive film is 40 ppm/° C. or less. 2. The film laminate according to claim 1, wherein the linear thermal expansion coefficient of the transparent substrate is 60 ppm/[deg.] C. or higher. 3. The film laminate according to claim 2 , wherein the conductive film further comprises a metal layer arranged in the thickness direction of the conductive layer. A step of preparing the film laminate according to any one of claims 1 to 3 ;
patterning the conductive layer;
a step of heating the film laminate;
and removing the carrier film from the film laminate.

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