JP2021143395A - Method for manufacturing transparent conductive film, and transparent conductive film - Google Patents

Abstract

To provide a transparent conductive film including a transparent conductive layer having a small variation in value of resistance in the transverse direction, and a transparent conductive film manufactured by the method for manufacturing a transparent conductive film.SOLUTION: A method for manufacturing a transparent conductive film 2 includes forming a transparent conductive layer 22 on one surface of a long-sized transparent film 10 while conveying the long-sized transparent film 10 in the longitudinal direction. The transparent conductive layer 22 is formed by sputtering while conveying the long-sized transparent film 10 along the peripheral surface of a film deposition roller 15; the thickness of the transparent conductive layer 22 is more than 35 nm; and a conveyance tension per unit area on a cross section perpendicular to the longitudinal direction of the long-sized transparent film 10 when forming the transparent conductive layer 22 is 3.3 N/mm2 or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a transparent conductive film and a transparent conductive film, and more particularly to a method for producing a transparent conductive film and a transparent conductive film produced by the method for producing the transparent conductive film.

Conventionally, a method of manufacturing a conductive film by laminating a transparent conductive layer on a base film by a roll-to-roll method has been known.

As such a method, for example, a method of producing a transparent conductive film by laminating an ITO film having a thickness of 25 nm by sputtering while transporting a long PET film base material along the peripheral surface of a film forming roll. It has been proposed (see, for example, Examples in Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-234996

On the other hand, when the transparent conductive layer is laminated on one surface of the long substrate while the long substrate is conveyed along the peripheral surface of the film forming roll, if the conveying tension is low, the film is formed with the long substrate. Adhesion with the roll may not be achieved, and the outside of the long base material in the width direction (both ends in the lateral direction) may rise.

In such a case, the outer side of the long base material in the lateral direction cannot be sufficiently cooled by the film forming roll.

Then, the transparent conductive layer laminated on the lateral side of the long base material is more crystallized than the transparent conductive layer laminated on the inner side of the long base material, and as a result, the surface resistance is low. Become.

On the other hand, from the viewpoint of lowering the surface resistance, it is considered to increase the thickness of the transparent conductive layer.

However, if the thickness of the transparent conductive layer is large, there is a problem that the difference in resistance between the transparent conductive layer laminated on the outside of the long base material and the transparent conductive layer laminated on the inside of the long base material becomes large. ..

The present invention provides a method for producing a transparent conductive film having a transparent conductive layer having a small variation in resistance value in the short direction, and a transparent conductive film produced by the method for producing the transparent conductive film. It is in.

The present invention [1] is a method for producing a transparent conductive film in which a transparent conductive film is formed on one surface of the long transparent film while transporting the long transparent film in the longitudinal direction. The long transparent film is formed by sputtering while being conveyed along the peripheral surface of the film forming roll, and the thickness of the transparent conductive layer exceeds 35 nm, and the long transparent film at the time of forming the transparent conductive layer is formed. This is a method for producing a transparent conductive film, wherein the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the film is 3.3 N / mm ^{2 or more.}

The present invention [2] includes the method for producing a transparent conductive film according to the above [1], wherein the long transparent film is a cycloolefin film.

The present invention [3] includes the method for producing a transparent conductive film according to the above [1] or [2], wherein the thickness of the long transparent film is 10 μm or more and 70 μm or less.

The present invention [4] includes the method for producing a transparent conductive film according to any one of the above [1] to [3], wherein the transparent conductive layer contains an amorphous portion.

The present invention [5] includes the method for producing a transparent conductive film according to any one of the above [1] to [4], wherein the transparent conductive layer contains an indium tin composite oxide as a main component. ..

The present invention [6] includes the method for producing a transparent conductive film according to any one of the above [1] to [5], wherein the surface temperature of the film forming roll is 20 ° C. or higher and 60 ° C. or lower. I'm out.

In the present invention [7], a long transparent film and a transparent conductive layer are provided in order, the thickness of the transparent conductive layer exceeds 35 nm, and the first resistance difference and the second resistance difference measured by the following tests are , -10Ω / □ or more and 10Ω / □ or less, including a transparent conductive film.

Test: A value obtained by subtracting _{the resistance value R 50} of the 50 mm portion from the one side end in the lateral direction _{of the transparent conductive film by the resistance value R 30} of 30 mm from the one side end in the lateral direction of the transparent conductive film. (R _50- R ₃₀ ) is calculated as the first resistance difference. Separately, the resistance value R ₅₀ ′ of the 50 mm portion is subtracted from the other end of the transparent conductive film in the lateral direction by the resistance value R _{30 ′ of 30 mm from the other end of the transparent conductive film in the lateral direction.} The value (R ₅₀ ′ −R ₃₀ ′) is calculated as the second resistance difference.

In the method for producing a transparent conductive film of the present invention, the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film is 3.3 N / mm ² or more. As a result, the long transparent film and the film forming roll can be brought into close contact with each other, and it is possible to prevent the outside of the long transparent film in the lateral direction (both sides in the lateral direction) from being lifted. Then, since the film-forming roll can sufficiently cool the outside of the long transparent film in the short direction to the same extent as the inside of the long transparent film in the short direction, the film is laminated on the outside of the long transparent film in the short direction. Crystallization of the transparent conductive layer can be suppressed. As a result, the difference in resistance between the transparent conductive layer laminated on the outer side of the long transparent film in the lateral direction and the transparent conductive layer laminated on the inner side in the lateral direction of the long transparent film can be reduced. In other words, the variation in the resistance value of the transparent conductive layer can be reduced in the lateral direction of the long transparent film.

Further, in the method for producing the transparent conductive film, the thickness of the transparent conductive layer exceeds 35 nm. Therefore, the surface resistance of the transparent conductive layer can be lowered.

In the transparent conductive film of the present invention, the first resistance difference and the second resistance difference are in a predetermined range. Therefore, the variation in the resistance value of the transparent conductive layer can be reduced in the lateral direction of the long transparent film.

FIG. 1 shows a schematic view of an embodiment of a film manufacturing apparatus used in one embodiment of the method for manufacturing a transparent conductive film of the present invention. FIG. 2 is a graph showing the results of surface resistance of Example 1 and Comparative Example 1.

In one embodiment of the method for producing a transparent conductive film of the present invention, the transparent conductive layer 22 is formed on one surface of the long transparent film 10 while the long transparent film 10 is conveyed in the longitudinal direction.

Hereinafter, an embodiment of the film manufacturing apparatus used in this method will be described with reference to FIG.

In FIG. 1, the left-right direction of the paper surface is the transport direction, the right side of the paper surface is the downstream side of the transport direction, and the left side of the paper surface is the upstream side of the transport direction. The paper thickness direction is the width direction, with the front side of the paper surface being one side in the width direction and the back side of the paper surface being the other side in the width direction. The vertical direction of the paper surface is the vertical direction, with the upper side of the paper surface being the upper side and the lower side of the paper surface being the lower side.

The film manufacturing apparatus 1 is an apparatus for manufacturing a transparent conductive film 2 that is long in the transport direction, and includes a delivery unit 5, a sputter unit 6, and a winding unit 7 as shown in FIG. ..

The delivery unit 5 includes a delivery roll 11, a first guide roll 12, and a delivery chamber 13.

The delivery roll 11 is a cylindrical member having a rotation axis for delivering the long transparent film 10. The delivery roll 11 is arranged at the uppermost stream in the transport direction of the film manufacturing apparatus 1. A motor (not shown) for rotating the delivery roll 11 is connected to the delivery roll 11.

The first guide roll 12 is a rotating member that guides the long transparent film 10 delivered from the delivery roll 11 to the sputter unit 6. The first guide roll 12 is arranged on the downstream side in the transport direction of the delivery roll 11 and on the upstream side in the transport direction of the second guide roll 23 (described later).

The delivery chamber 13 is a casing that houses the delivery roll 11 and the first guide roll 12. The delivery chamber 13 is provided with a vacuum unit that allows the inside to be evacuated.

The sputtering unit 6 laminates the transparent conductive layer 22 (described later) on the long transparent film 10 conveyed from the delivery unit 5 by a sputtering method. The sputter unit 6 is arranged adjacent to the delivery unit 5 on the downstream side in the transport direction and on the upstream side of the take-up unit 7 in the transport direction. The sputter unit 6 includes a second guide roll 23, a third guide roll 14, a film forming roll 15, a target 16, a fourth guide roll 17, and a film forming chamber 18.

The second guide roll 23 is a rotating member that guides the long transparent film 10 conveyed from the delivery unit 5 (first guide roll 12) to the third guide roll 14. The second guide roll 23 is arranged on the downstream side of the first guide roll 12 in the transport direction and on the upstream side of the third guide roll 14 in the transport direction.

A tension meter (not shown) for measuring the transport tension of the long transparent film 10 is connected to the second guide roll 23.

The third guide roll 14 is a rotating member that guides the long transparent film 10 conveyed from the second guide roll 23 to the film forming roll 15. The third guide roll 14 is arranged on the downstream side in the transport direction of the second guide roll 23 and on the upstream side in the transport direction of the film forming roll 15.

The film forming roll 15 is a cylindrical member having a rotation axis for laminating the transparent conductive layer 22 on the long transparent film 10. The film forming roll 15 conveys the long transparent film 10 along the peripheral surface of the film forming roll 15. The film forming roll 15 is arranged on the downstream side of the third guide roll 14 in the transport direction and on the upstream side of the fourth guide roll 17 in the transport direction.

The target 16 is formed of the material of the transparent conductive layer 22. The target 16 is arranged in the vicinity of the film forming roll 15. Specifically, the target 16 is arranged on the lower side of the film forming roll 15 so as to face the film forming roll 15 at intervals.

When the transparent conductive layer 22 includes a first region (described later) and a second region (described later), the material of the first region and the material of the second region are separately prepared as the target 16.

Specifically, the targets 16 are arranged in order from the upstream side in the transport direction to the downstream side in the transport direction at intervals of the first target (not shown) and the second region formed from the material of the first region. It comprises a second target (not shown) formed from the material.

The fourth guide roll 17 is a rotating member that guides the transparent conductive film 2 conveyed from the film forming roll 15 to the winding unit 7. The fourth guide roll 17 is arranged on the downstream side in the transport direction of the film forming roll 15 and on the upstream side in the transport direction of the fifth guide roll 19 (described later).

The film forming chamber 18 is a casing that houses the second guide roll 23, the third guide roll 14, the film forming roll 15, the target 16, and the fourth guide roll 17. The film forming chamber 18 is provided with a vacuum unit that allows the inside to be evacuated.

The take-up unit 7 includes a fifth guide roll 19, a take-up roll 20, and a take-up chamber 21. The take-up unit 7 is arranged on the downstream side of the sputtering unit 6 in the transport direction so as to be adjacent to the sputtering unit 6.

The fifth guide roll 19 is a rotating member that guides the transparent conductive film 2 conveyed from the sputter unit 6 to the take-up roll 20. The fifth guide roll 19 is arranged on the downstream side in the transport direction of the fourth guide roll 17 and on the upstream side in the transport direction of the take-up roll 20.

The take-up roll 20 is a cylindrical member having a rotation axis for taking up the transparent conductive film 2. The take-up roll 20 is arranged at the most downstream side in the transport direction of the film manufacturing apparatus 1. A motor (not shown) for rotating the take-up roll 20 is connected to the take-up roll 20.

The take-up chamber 21 is a casing that houses the take-up roll 20 and the fifth guide roll 19. The take-up chamber 21 is provided with a vacuum unit that allows the inside to be evacuated.

Next, an embodiment of a method of manufacturing the transparent conductive film 2 using the film manufacturing apparatus 1 will be described.

In the method of manufacturing the transparent conductive film 2, the transparent conductive layer 22 is formed on one surface of the long transparent film 10 while the long transparent film 10 is conveyed in the longitudinal direction.

In order to convey the long transparent film 10 in the longitudinal direction, first, the long transparent film 10 is prepared.

Examples of the long transparent film 10 include a long polymer film. Examples of the material of the polymer film include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, (meth) acrylic resins such as polymethacrylate, and olefin resins such as polyethylene, polypropylene, and cycloolefin polymers. For example, polycarbonate resin, polyether sulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin and the like can be mentioned, preferably an olefin resin, and more preferably a cycloolefin polymer. ..

Examples of the cycloolefin polymer include a polymerization product of a cycloolefin monomer and a polymerization product of a cycloolefin monomer and an olefin such as ethylene.

Examples of the cycloolefin monomer include polycyclic olefins such as norbornene, methylnorbornene, dimethylnorbornene, etilidennorbornene, butylnorbornene, dicyclopentadiene, dihydrodicyclopentadiene, tetracyclododecene, and tricyclopentadiene. Examples thereof include monocyclic olefins such as cyclopentene, cicyclooctadien, and cyclooctatriene.

The cycloolefin monomer can be used alone or in combination of two or more.

If the material is a cycloolefin polymer (that is, if the long transparent film 10 is a cycloolefin film), the optical properties (including transparency) are excellent.

The thickness of the long transparent film 10 is, for example, 10 μm or more, preferably 30 μm or more, and for example, 100 mm or less.

When the thickness of the long transparent film 10 is at least the above lower limit, the transportability and handling are excellent.

If the thickness of the long transparent film 10 is not more than the above upper limit, the productivity is excellent.

The length (length in the width direction) of the long transparent film 10 in the lateral direction is, for example, 100 mm or more, preferably 200 mm or more, and for example, 5000 mm or less, preferably 2000 mm or less.

Further, a functional layer can be arranged in advance on one surface or the other surface of the long transparent film 10. In such a case, the obtained transparent conductive film 2 includes the long transparent film 10, the functional layer, and the transparent conductive layer 22 in this order, or the functional layer, the long transparent film 10, and the long transparent film 10. The transparent conductive layer 22 is provided in this order.

As the functional layer, for example, it is arranged on one surface of the long transparent film 10 such as a hard coat layer and an optical adjustment layer, for example, on the other surface of the long transparent film 10 such as an anti-blocking layer. The functional layer and the like can be mentioned.

The hard coat layer is formed from the hard coat composition.

The hard coat composition contains a resin and, if necessary, particles.

Examples of the resin include curable resins and thermoplastic resins (for example, polyolefin resins), and preferably curable resins.

Examples of the curable resin include an active energy ray-curable resin that is cured by irradiation with active energy rays (specifically, ultraviolet rays, electron beams, etc.), for example, a thermosetting resin that is cured by heating. Preferably, an active energy ray-curable resin is used.

Examples of the active energy ray-curable resin include polymers having a functional group having a polymerizable carbon-carbon double bond 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 the active energy ray-curable resin include (meth) acrylic ultraviolet-curable resins such as urethane acrylate and epoxy acrylate.

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

Examples of the particles include inorganic particles and organic particles.

Examples of the inorganic particles include metal oxide particles made of zirconium oxide, titanium oxide, zinc oxide, tin oxide and the like, and carbonate particles such as calcium carbonate.

Examples of the organic particles include crosslinked acrylic resin particles.

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

The hard coat composition is then obtained by mixing the resin and, if necessary, the particles to be blended.

Further, if necessary, a known additive such as a leveling agent, a thixotropy agent, and an antistatic agent can be added to the hard coat composition.

To form the hard coat layer, a diluted solution of the hard coat composition is applied to one surface of the long transparent film 10 in the thickness direction, dried, and then the hard coat composition is cured by ultraviolet irradiation.

As a result, a hard coat layer is formed.

From the viewpoint of scratch resistance, the thickness of the hard coat layer is, for example, 0.1 μm or more, preferably 0.5 μm or more, and for example, 10 μm or less, preferably 3 μm or less.

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

In such a case, the obtained transparent conductive film 2 includes a long transparent film 10, a hard coat layer, and a transparent conductive layer 22 in this order.

The optical adjustment layer is transparent in order to ensure excellent transparency of the transparent conductive film 2 while suppressing the pattern visibility of the transparent conductive layer 22 and suppressing reflection at the interface in the transparent conductive film 2. This is a layer for adjusting the optical physical characteristics (for example, the refractive index) of the conductive film 2.

The optical adjustment layer is formed from, for example, an optical adjustment composition.

The optical adjustment composition contains the above-mentioned resin and the above-mentioned particles.

Examples of the resin include the resins mentioned in the hard coat composition, and preferably (meth) acrylic ultraviolet curable resins.

Examples of the particles include the particles mentioned in the hard coat composition, and preferably zirconium oxide from the viewpoint of the refractive index.

Then, the optical adjustment composition is obtained by mixing the resin and the particles.

The optical conditioning composition can further contain known additives such as leveling agents, thixotropy agents, antistatic agents and the like.

To form the optical adjustment layer, a diluted solution of the optical adjustment composition is applied to one surface of the long transparent film 10 in the thickness direction, dried, and then the optical adjustment composition is cured by irradiation with ultraviolet rays.

As a result, an optical adjustment layer is formed.

From the viewpoint of scratch resistance, the thickness of the optical adjustment layer is, for example, 10 nm or more, preferably 50 nm or more, and for example, 200 nm or less. The thickness of the optical adjustment layer can be measured by cross-sectional observation using, for example, a transmission electron microscope.

In such a case, the obtained transparent conductive film 2 includes a long transparent film 10, an optical adjustment layer, and a transparent conductive layer 22 in this order.

The anti-blocking layer imparts blocking resistance to the respective surfaces of the plurality of transparent conductive films 2 in contact with each other when the transparent conductive films 2 are laminated in the thickness direction.

The material of the anti-blocking layer is, for example, an anti-blocking composition.

Examples of the anti-blocking composition include the mixture described in JP-A-2016-179686.

To form the anti-blocking layer, a diluted solution of the anti-blocking composition is applied to the other surface of the long transparent film 10 in the thickness direction, dried, and then the anti-blocking composition is cured by irradiation with ultraviolet rays.

As a result, an anti-blocking layer is formed.

In such a case, the obtained transparent conductive film 2 includes an anti-blocking layer, a long transparent film 10, and a transparent conductive layer 22 in this order.

The thickness of the anti-blocking layer is, for example, 0.1 μm or more, and is, for example, 10 μm or less.

One layer or two or more functional layers can be arranged on the long transparent film 10, and preferably, the hard coat layer and the optical adjustment layer are arranged in order on the long transparent film 10 in advance. That is, the obtained transparent conductive film 2 includes a long transparent film 10, a hard coat layer, an optical adjustment layer, and a transparent conductive layer 22 in this order.

In such a case, a hard coat layer is formed on one side of the long transparent film 10 in the thickness direction by the above method, and then a diluted solution of the optical adjustment composition is applied to one side of the hard coat layer in the thickness direction. After coating and drying, the optical adjustment composition is cured by irradiation with ultraviolet rays.

Then, the long transparent film 10 is placed on the delivery roll 11. That is, the roll body in which the long transparent film 10 is wound in a roll shape is attached to the delivery roll 11.

As a result, the long transparent film 10 is prepared.

Next, the long transparent film 10 is conveyed in the longitudinal direction.

Specifically, the delivery roll 11 and the take-up roll 20 are rotationally driven by a motor to feed the long transparent film 10 from the delivery roll 11, and the first guide roll 12, the second guide roll 23, and the third guide roll 14 are sent out. , The film forming roll 15, the fourth guide roll 17, and the fifth guide roll 19 are conveyed in this order, and are wound by the winding roll 20.

As a result, the long transparent film 10 is conveyed from the delivery roll 11 to the take-up roll 20 in the transfer direction by a roll-to-roll method.

The transport speed is, for example, 3 m / min or more, and for example, 15 m / min or less.

Next, the transparent conductive layer 22 is formed on one surface of the long transparent film 10 while conveying the long transparent film 10 in the longitudinal direction.

Specifically, sputtering is performed while conveying the long transparent film 10 in the longitudinal direction. That is, the sputter unit 6 is operated to form the transparent conductive layer 22 on the long transparent film 10.

Specifically, a gas (argon or the like) is supplied to the inside of the film forming chamber 18 under vacuum, and a voltage is applied to cause the gas to collide with the target 16. As a result, the target material ejected from the target 16 is adhered to the lower surface (one side) of the long transparent film 10 transported from the upstream side in the transport direction below the film forming roll 15, and the transparent conductive layer 22 is formed. It is formed.

That is, in this method, the transparent conductive layer 22 is formed by sputtering while transporting the long transparent film 10 along the peripheral surface of the film forming roll 15.

At this time, the long transparent film 10 is preferably in close contact with each other along the circumferential direction of the film forming roll 15 by 180 ° or more.

The material of the target 16, that is, the material of the transparent conductive layer 22, is, for example, a metal oxide such as an indium tin composite oxide or an antimonthine composite oxide, for example, aluminum nitride, titanium nitride, tantalum nitride, chromium nitride, gallium nitride. And metal nitrides such as these composite nitrides, such as metals such as gold, silver, copper, nickel and alloys thereof, preferably indium tin composite oxides.

That is, preferably, the transparent conductive layer 22 contains an indium tin composite oxide as a main component.

When the transparent conductive layer 22 contains an indium tin composite oxide as a main component, the specific resistance of the transparent conductive layer 22 can be lowered.

When an indium tin composite oxide is used as the material of the transparent conductive layer 22, the content ratio of tin oxide is, for example, 0.5% by mass or more, preferably 3% by mass, based on the total amount of tin oxide and indium oxide. The above is more preferably 5% by mass or more, further preferably 8% by mass or more, particularly preferably 9% by mass or more, and for example, 20% by mass or less, preferably 15% by mass or less.

When the content ratio of tin oxide is equal to or higher than the above lower limit, the resistance reduction is promoted. When the content ratio of tin oxide is not more than the above upper limit, the transparent conductive layer 22 is excellent in strength.

Further, preferably, the transparent conductive layer 22 can include a region in which the proportion of tin oxide is 8% by mass or more. When the transparent conductive layer 22 includes a region in which the proportion of tin oxide is 8% by mass or more, the surface resistance value can be reduced.

For example, the transparent conductive layer 22 has a first region as an example of a region in which the ratio of tin oxide is 8% by mass or more, and a second region in which the ratio of tin oxide is lower than the ratio of tin oxide in the first region. include. Specifically, the transparent conductive layer 22 sequentially includes a layered first region and a layered second region arranged on one surface in the thickness direction of the first region. The boundary between the first region and the second region is not confirmed by observation with a measuring device, and it is permissible that the boundary is unclear. The transparent conductive layer 22 may have a concentration gradient in which the tin oxide concentration gradually increases from one surface in the thickness direction to the other surface. When the transparent conductive layer 22 includes a second region in addition to the first region described above, a desired crystallization rate can be obtained by adjusting the ratio of that region.

The proportion of tin oxide in the first region is preferably 9% by mass or more and 20% by mass or less.

The ratio of the thickness of the first region to the thickness of the transparent conductive layer 22 is, for example, more than 50%, preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and for example. , 99% or less, preferably 97% or less.

When the ratio of the thickness of the first region is equal to or higher than the above-mentioned lower limit, the ratio of tin oxide in the transparent conductive layer 22 can be increased, and therefore the surface resistance value can be sufficiently lowered.

The proportion of tin oxide in the second region is, for example, less than 8% by mass, preferably 7% by mass or less, more preferably 5% by mass or less, still more preferably 4% by mass or less, and for example, 1. By mass or more, preferably 2% by mass or more, more preferably 3% by mass or more.

The ratio of the thickness of the second region to the thickness of the transparent conductive layer 22 is, for example, 1% or more, preferably 3% or more, and for example, 50% or less, preferably 30% or less, more preferably. It is 20% or less, more preferably 10% or less.

The ratio of the ratio of tin oxide in the first region to the ratio of tin oxide in the second region (ratio of tin oxide in the first region / ratio of tin oxide in the second region) is, for example, 1.5 or more, preferably 1.5 or more. 2, 2 or more, more preferably 2.5 or more, and for example, 5 or less, preferably 4 or less.

The tin oxide concentration in each of the transparent conductive layer 22, the first region and the second region is measured by X-ray photoelectron spectroscopy. Alternatively, the tin oxide content can be estimated from the target component (known) used when forming the amorphous transparent conductive layer 22 by sputtering.

Further, since the target material ejected from the target 16 is heated to, for example, 100 ° C. or higher and 200 ° C. or lower, in this method, the transparent conductive layer 22 is cooled by the film forming roll 15 and the transparent conductive layer 22 is cooled. Suppresses crystallization.

Specifically, the temperature of the film forming roll 15 is, for example, 20 ° C. or higher, and for example, 60 ° C. or lower.

When the temperature of the film forming roll 15 is equal to or higher than the above lower limit or lower than the above upper limit, the transparent conductive layer 22 can be sufficiently cooled and the crystallization of the transparent conductive layer 22 can be suppressed (amorphous transparent conductive layer). 22 can be obtained.).

Further, the transport tension of the long transparent film 10 at the time of forming the transparent conductive layer 22 is, for example, 250 N or more, preferably 330 N or more, more preferably 420 N or more, and for example, 600 N or less, preferably 600 N or less. It is 500 N or less.

The transport tension can be determined by a tension meter.

Further, the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film 10 at the time of forming the transparent conductive layer 22 is 3.3 N / mm ² or more, preferably 4.5 N / mm ² or more. more preferably at 6.0 N / mm ² or more, and is, for example, is 10 N / mm ² or less.

The transport tension can be calculated by the following formula (1).

Transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film 10 = Transport tension of the long transparent film 10 / (length in the width direction of the long transparent film 10 × width direction of the long transparent film 10) Thickness) (1)
When the transport tension is equal to or higher than the above lower limit, the long transparent film 10 and the film forming roll 15 can be sufficiently brought into close contact with each other, and the long transparent film 10 is outside in the width direction (outside in the lateral direction (both sides)). Can be suppressed from rising. Then, the film-forming roll 15 can sufficiently cool the outside of the long transparent film 10 in the short direction to the same extent as the inside of the long transparent film 10 in the short direction, so that the outside of the long transparent film 10 in the short direction can be sufficiently cooled. Crystallization of the transparent conductive layer 22 laminated on the above can be suppressed. As a result, the difference in resistance between the transparent conductive layer 22 laminated on the outer side of the long transparent film 10 in the lateral direction and the transparent conductive layer 22 laminated on the inner side in the lateral direction of the long transparent film 10 is reduced. Can be done. In other words, the variation in the resistance value of the transparent conductive layer 22 can be reduced in the lateral direction of the long transparent film 10.

Further, in particular, when the temperature of the film forming roll 15 is low (specifically, 20 ° C. or higher and 60 ° C. or lower), the long transparent film 10 is formed from the viewpoint of wrinkles. The resistance value of the transparent conductive layer 22 tends to vary greatly in the lateral direction. However, in this method, per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film 10 when the transparent conductive layer 22 is formed. Since the transport tension is equal to or higher than the above lower limit, the variation in the resistance value of the transparent conductive layer 22 on the lateral side of the transparent conductive film 2 in the lateral direction can be reduced.

On the other hand, if the transport tension is less than the above lower limit, the long transparent film 10 and the film forming roll 15 cannot be sufficiently brought into close contact with each other, and it is possible to prevent both ends of the long transparent film 10 from floating in the lateral direction. Can not do it. Then, the film-forming roll 15 cannot sufficiently cool the transparent conductive layer 22 to the same extent as the inside of the long transparent film 10 in the short direction, and the long transparent film 10 is short in the short direction. Only the outer side of the direction crystallizes, and the variation in the resistance value of the transparent conductive layer 22 increases in the lateral direction of the transparent conductive film 2.

From the above, in this method, since the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film 10 is 3.3 N / mm ² or more, even if the transparent conductive layer 22 is thick (specifically). In the short direction of the long transparent film 10 exceeding 35 nm (described later), the variation in the resistance value of the transparent conductive layer 22 can be reduced.

As a result, the transparent conductive film 2 including the long transparent film 10 and the transparent conductive layer 22 laminated on the lower surface (one surface) thereof in order is obtained on the lower side of the film forming roll 15.

After that, the transparent conductive film 2 produced on the lower side of the film forming roll 15 is conveyed by the film forming roll 15 and the fourth guide roll 17 toward the take-up roll 20 on the downstream side in the conveying direction.

In the obtained transparent conductive film 2, the transparent conductive layer 22 preferably contains an amorphous portion, and more preferably consists of only an amorphous portion.

The transparent conductive layer 22 is excellent in flexibility when it contains an amorphous portion.

The thickness of the transparent conductive layer 22 exceeds 35 nm, and is, for example, 100 nm or less, preferably 65 nm or less.

When the thickness of the transparent conductive layer 22 is at least the above lower limit, the surface resistance of the transparent conductive layer 22 can be lowered.

The surface resistance value of the transparent conductive layer 22 is, for example, 65 Ω / □ or less, and for example, 35 Ω / □ or more. The surface resistance value can be measured by the 4-terminal method in accordance with JIS K7194.

Then, such a transparent conductive film 2 includes a long transparent film 10 and a transparent conductive layer 22 in this order.

Further, as described above, the variation in the resistance value of the transparent conductive layer 22 in the lateral direction of the transparent conductive film 2 is small.

Specifically, both the first resistance difference and the second resistance difference measured by the test described later are -10Ω / □ or more, preferably -8Ω / □ or more, and 10Ω / □ or less, preferably 10Ω / □ or less. Is 5Ω / □ or less.

Specifically, in the test, the lateral direction one side end portion of the transparent conductive film 2, the resistance value R ₅₀ of 50mm portion of the lateral direction one side end portion of the transparent conductive film 2, 30 mm of the resistance value The value (R _50- R _{30 ) subtracted by R 30} is calculated as the first resistance difference. _{Separately, the resistance value R 50} ′ of the portion 50 mm from the other side end portion in the lateral direction _{of the transparent conductive film 2 and the resistance value R 30} ′ of 30 mm from the other side end portion in the lateral direction of the transparent conductive film 2. The value subtracted in (R ₅₀ ′ −R ₃₀ ′) is calculated as the second resistance difference.

The standard deviation obtained by the surface resistance measurement described later is, for example, 10 or less, preferably 8 or less.

Since such a transparent conductive film 2 has a small variation in the resistance value of the transparent conductive layer 22 in the lateral direction of the transparent conductive film 2, the transparent conductive film 2 is heated to crystallize the transparent conductive layer 22. It is possible to suppress the occurrence of cracks at the time of conversion.

The surface resistance value of the transparent conductive layer 22 (transparent conductive layer 22 after crystallization) at this time is, for example, 100 Ω / □ or less, preferably 60 Ω / □ or less, and for example, 1 Ω / □ or more. Is.

Examples and comparative examples are shown below, and the present invention will be described in more detail. The present invention is not limited to Examples and Comparative Examples. In addition, specific numerical values such as the compounding ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned "Form for carrying out the invention", and the compounding ratios corresponding to them ( Substitute the upper limit value (value defined as "less than or equal to" or "less than") or the lower limit value (value defined as "greater than or equal to" or "excess") such as content ratio), physical property value, parameter, etc. be able to.
1. 1. Production of transparent conductive film Example 1
As the long transparent film, a cycloolefin polymer (COP) film (manufactured by Zeon Co., Ltd., trade name "Zeonoa", thickness 43 μm, length 1586 mm in the lateral direction) was used.

Next, a hard coat composition (ultraviolet curable resin made of an acrylic resin) was applied to one surface of the cycloolefin polymer film and cured by ultraviolet irradiation to form a hard coat layer having a thickness of 1 μm.

Next, an optical adjustment composition (ultraviolet curable composition containing zirconia particles having a refractive index of 1.62) is applied to one surface of the hard coat layer and cured by ultraviolet irradiation to form an optical adjustment layer having a thickness of 100 nm. Formed.

The cycloolefin polymer film was then placed on a delivery roll in the film manufacturing apparatus. That is, the roll body in which the cycloolefin polymer film was wound in a roll shape was attached to the delivery roll.

Next, the delivery roll and the take-up roll were rotationally driven by a motor to transport the cycloolefin polymer from the delivery roll to the take-up roll in the transport direction by a roll-to-roll method.

Next, an amorphous transparent conductive layer having a thickness of 40 nm was formed on one surface of the optical adjustment layer in the thickness direction by sputtering. Specifically, first, a first target made of ITO having a tin oxide concentration of 10% by weight and a second target made of ITO having a tin oxide concentration of 3.3% by weight were placed in a film manufacturing apparatus.

Then, sputtering was performed so that the ratio of the thickness of the first region and the ratio of the thickness of the second region in the amorphous transparent conductive layer were 95% and 5%, respectively.

Further, the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film at the time of forming the transparent conductive layer was 7.04 N / mm ² .

The transport tension of the long transparent film 10 at the time of forming the transparent conductive layer 22 is determined by a tension meter, and the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film at the time of forming the transparent conductive layer 22 is obtained. Was calculated by the above formula (1).

As a result, the cycloolefin polymer film, the hard coat layer, the optical adjustment layer, and the transparent conductive layer (first region (tin oxide concentration 10% by mass) and second region (tin oxide concentration 3.3% by mass)) A transparent conductive film was obtained in this order.

Examples 2 to 4, Comparative Example 1 and Comparative Example 2
According to the description in Table 1, the same as in Example 1 except that the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film at the time of forming the transparent conductive layer and the thickness of the transparent conductive layer are changed. A transparent conductive film was obtained by the procedure of.
2. Evaluation (surface resistance)
The surface resistance of the transparent conductive layer of each Example and each Comparative Example was measured by the 4-terminal method in accordance with JIS K7194. Measurements were carried out every 20 mm toward the inside of the 30 mm portions at both ends of the transparent conductive film in the lateral direction.

From the obtained results, the maximum value, the minimum value, the average value, the standard deviation, the first resistance difference, and the second resistance difference of the surface resistance values are calculated, and the results are shown in Table 1.
(Crystallization of transparent conductive layer and surface resistance of transparent conductive layer after crystallization)
The transparent conductive films of each Example and each Comparative Example were heated at 130 ° C. for 90 minutes to crystallize the amorphous transparent conductive layer to prepare a crystalline transparent conductive layer.

Then, the surface resistance of the transparent conductive layer was measured by the 4-terminal method in accordance with JIS K7194. The results are shown in Table 1 and FIG.

2 Transparent conductive film 10 Long transparent film 15 Film-forming roll 22 Transparent conductive layer

Claims (7)

A method for producing a transparent conductive film in which a transparent conductive layer is formed on one surface of the long transparent film while conveying the long transparent film in the longitudinal direction.
The transparent conductive layer is formed by sputtering while transporting the long transparent film along the peripheral surface of the film forming roll.
The thickness of the transparent conductive layer exceeds 35 nm,
Production of a transparent conductive film, characterized in that the transport tension per unit area of the cross section perpendicular to the longitudinal direction of the long transparent film at the time of forming the transparent conductive layer is 3.3 N / mm ^{2 or more.} Method. The method for producing a transparent conductive film according to claim 1, wherein the long transparent film is a cycloolefin film. The method for producing a transparent conductive film according to claim 1 or 2, wherein the thickness of the long transparent film is 10 μm or more and 70 μm or less. The method for producing a transparent conductive film according to any one of claims 1 to 3, wherein the transparent conductive layer contains an amorphous portion. The method for producing a transparent conductive film according to any one of claims 1 to 4, wherein the transparent conductive layer contains an indium tin composite oxide as a main component. The method for producing a transparent conductive film according to any one of claims 1 to 5, wherein the surface temperature of the film-forming roll is 20 ° C. or higher and 60 ° C. or lower. A long transparent film and a transparent conductive layer are provided in order,
The thickness of the transparent conductive layer exceeds 35 nm,
A transparent conductive film characterized in that the first resistance difference and the second resistance difference measured by the following tests are -10Ω / □ or more and 10Ω / □ or less.
Test: A value obtained by subtracting _{the resistance value R 50} of the 50 mm portion from the one side end in the lateral direction _{of the transparent conductive film by the resistance value R 30} of 30 mm from the one side end in the lateral direction of the transparent conductive film. (R _50- R ₃₀ ) is calculated as the first resistance difference. Separately, the resistance value R ₅₀ ′ of the 50 mm portion is subtracted from the other end of the transparent conductive film in the lateral direction by the resistance value R _{30 ′ of 30 mm from the other end of the transparent conductive film in the lateral direction.} The value (R ₅₀ ′ −R ₃₀ ′) is calculated as the second resistance difference.

Images