KR20240058798A - Method for manufacturing transparent conductive film - Google Patents

Abstract

The manufacturing method of the transparent conductive film 3 includes a first step of preparing a long substrate 1 and a second step of forming a transparent conductive layer 2 on one side of the substrate 1 in the thickness direction under a vacuum atmosphere. and a third step of heating the transparent conductive layer 2 using the heating roll 22 in a vacuum atmosphere.

Description

Method for manufacturing transparent conductive film

The present invention relates to a method for producing a 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 is known.

In this method, for example, an amorphous transparent conductive layer is formed by sputtering in a vacuum atmosphere and in the presence of argon gas while transporting a long transparent film base material by a roll-to-roll method, and then the amorphous transparent conductive layer is formed in a vacuum atmosphere. A method of producing a transparent conductive film has been proposed by heating a transparent film substrate on which a transparent conductive layer is formed with an infrared heater to crystallize the transparent conductive layer (for example, see Patent Document 1).

Japanese Patent Publication No. 2016-056423

On the other hand, methods for producing transparent conductive films require even higher productivity.

The present invention aims to provide a method for producing a transparent conductive film capable of forming a transparent conductive layer with excellent productivity.

The present invention [1] includes a first step of preparing a long substrate, a second step of forming a transparent conductive layer on one side of the substrate in the thickness direction under a vacuum atmosphere, and forming the transparent conductive layer using a heating roll under a vacuum atmosphere. A method for producing a transparent conductive film comprising a third step of heating the layer.

The present invention [2] includes the method for producing a transparent conductive film according to the above [1], in which the first process, the second process and the third process are performed in a roll-to-roll manner.

In the method for producing a transparent conductive film of the present invention, in the third step, the transparent conductive layer is heated using a heating roll in a vacuum atmosphere. As a result, the transparent conductive layer can be sufficiently crystallized.

1 shows a schematic diagram of one embodiment of a film production apparatus used in one embodiment of the method for producing a transparent conductive film of the present invention.

In one embodiment of the method for producing a transparent conductive film of the present invention, a transparent conductive layer 2 is formed on one side of the long substrate 1 in the thickness direction while conveying the long substrate 1 in the longitudinal direction.

Hereinafter, one embodiment of the film manufacturing apparatus used in this method will be described with reference to FIG. 1.

<Film manufacturing device>

In Fig. 1, the left and right direction of the paper is the conveyance direction. The right side of the ground is on the downstream side in the conveyance direction. The left side of the page is upstream of the conveyance direction. Additionally, the conveyance direction is a conveyance direction between neighboring units, not a conveyance direction within each unit. The paper thickness direction is the width direction. The front side of the ground is on one side in the width direction. The ground depth side is the other side in the width direction. The direction above and below the ground is up and down. The upper side of the ground is the upper side. The lower side of the ground is the lower side.

The film manufacturing apparatus 10 is an apparatus for manufacturing a long transparent conductive film 3. As shown in FIG. 1, the film manufacturing apparatus 10 includes a sending unit 5, a sputtering unit 6, a first annealing unit 7, a second annealing unit 8, and a winding unit 9. Equipped with

[Transmission unit]

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 sending out the long substrate 1. The delivery roll 11 is arranged at the most upstream part of the film manufacturing apparatus 10 in the conveyance direction. 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 base material 1 delivered from the delivery roll 11 to the sputter unit 6. The first guide roll 12 is disposed on the downstream side in the conveyance direction of the delivery roll 11 and on the upstream side in the conveyance direction of the second guide roll 14 (described later).

The delivery chamber 13 is a casing that accommodates the delivery roll 11 and the first guide roll 12. A vacuum unit is installed in the delivery chamber 13 to vacuum the interior.

[Sputter unit]

The sputter unit 6 laminates (forms) the transparent conductive layer 2 on the long base material 1 conveyed from the delivery unit 5 by a sputtering method. The sputter unit 6 is disposed on the downstream side in the conveyance direction of the delivery unit 5 and on the upstream side in the conveyance direction of the first anneal unit 7 so as to be adjacent to them. The sputter unit 6 includes a second guide roll 14, a third guide roll 15, a film forming roll 16, a target 17, a fourth guide roll 18, and a first chamber ( 19) is provided.

The second guide roll 14 is a rotating member that guides the long substrate 1 conveyed from the delivery unit 5 (first guide roll 12) to the third guide roll 15. The second guide roll 14 is disposed on the downstream side of the first guide roll 12 in the conveyance direction and on the upstream side of the third guide roll 15 in the conveyance direction.

The third guide roll 15 is a rotating member that guides the long base material 1 conveyed from the second guide roll 14 to the film forming roll 16. The third guide roll 15 is disposed on the downstream side in the conveyance direction of the second guide roll 14 and on the upstream side in the conveyance direction of the film-forming roll 16.

The film forming roll 16 is a cylindrical member having a rotation axis for laminating (forming) the transparent conductive layer 2 on the elongated base material 1. The film forming roll 16 conveys the long base material 1 along the circumferential surface of the film forming roll 16 . The film-forming roll 16 is disposed on the downstream side of the third guide roll 15 in the conveyance direction and on the upstream side of the fourth guide roll 18 in the conveyance direction.

The target 17 is formed of a material containing atoms constituting the transparent conductive layer 2, and is preferably formed of the material of the transparent conductive layer 2. The target 17 is arranged in the vicinity of the film forming roll 16. Specifically, the target 17 is disposed on the lower side of the deposition roll 16 to face the deposition roll 16 at an interval.

The fourth guide roll 18 guides the long substrate 1 (the long substrate 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the film forming roll 16 to the first anneal unit 7. It is a rotating member that guides. The fourth guide roll 18 is disposed on the downstream side in the conveyance direction of the film-forming roll 16 and on the upstream side in the conveyance direction of the fifth guide roll 20 (described later).

The first chamber 19 is a casing that accommodates the second guide roll 14, the third guide roll 15, the film forming roll 16, the target 17, and the fourth guide roll 18. A vacuum unit is installed in the first chamber 19 to vacuum the interior.

[First anneal unit]

The first annealing unit 7 heats the long substrate 1 (the long substrate 1 on which the transparent conductive layer 2 is laminated (formed)) transported from the sputter unit 6 to form the transparent conductive layer 2. ) is crystallized.

In other words, the first anneal unit 7 heats the transparent conductive layer 2 to crystallize it. The first anneal unit 7 is located downstream in the conveyance direction of the sputter unit 6 and is disposed adjacent to the upstream side of the second anneal unit 8 in the conveyance direction. The first anneal unit 7 includes a fifth guide roll 20, a sixth guide roll 21, a first heating roll 22, a seventh guide roll 23, and a second chamber 24. is provided.

The fifth guide roll 20 is a long base material 1 (long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the sputter unit 6 (the fourth guide roll 18). ) is a rotating member that guides the sixth guide roll (21). The fifth guide roll 20 is disposed on the downstream side of the fourth guide roll 18 in the conveyance direction and on the upstream side of the sixth guide roll 21 in the conveyance direction.

The sixth guide roll 21 is a rotating member that guides the long base material 1 conveyed from the fifth guide roll 20 to the first heating roll 22. The sixth guide roll 21 is disposed on the downstream side of the fifth guide roll 20 in the conveyance direction and on the upstream side of the first heating roll 22 in the conveyance direction.

The first heating roll 22 is a cylindrical member having a rotation axis for heating the transparent conductive layer 2. The second heating roll 27 conveys the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) along the circumferential surface of the first heating roll 22 . The first heating roll 22 is disposed on the downstream side of the sixth guide roll 21 in the conveyance direction and on the upstream side of the seventh guide roll 23 in the conveyance direction.

The seventh guide roll 23 transfers the long substrate 1 (the long substrate 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the first heating roll 22 to the second anneal unit ( 8) It is a rotating member that guides. The seventh guide roll 23 is disposed on the downstream side in the conveyance direction of the first heating roll 22 and on the upstream side in the conveyance direction of the eighth guide roll 25 (described later).

The second chamber 24 is a casing that accommodates the fifth guide roll 20, the sixth guide roll 21, the first heating roll 22, and the seventh guide roll 23. A vacuum unit is installed in the second chamber 24 to vacuum the interior.

[Second anneal unit]

The second annealing unit 8 heats the long substrate 1 (the long substrate 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the first annealing unit 7 to form a transparent conductive layer. (2) is crystallized. In other words, the second anneal unit 8 heats the transparent conductive layer 2 to crystallize it. In detail, the second annealing unit 8 crystallizes the transparent conductive layer 2 that could not be crystallized by heating with the first heating roll 22. The second anneal unit 8 is located on the downstream side in the conveyance direction of the first anneal unit 7 and is arranged adjacent to the upstream side in the conveyance direction of the winding unit 9.

The second anneal unit 8 includes an eighth guide roll 25, a ninth guide roll 26, a second heating roll 27, a tenth guide roll 28, and a third chamber 29. is provided.

The eighth guide roll 25 is a long substrate 1 (a long substrate on which the transparent conductive layer 2 is laminated (formed)) conveyed from the first annealing unit 7 (the seventh guide roll 23). 1)) is a rotating member that guides the 9th guide roll (26). The eighth guide roll 25 is disposed on the downstream side of the seventh guide roll 23 in the conveyance direction and on the upstream side of the ninth guide roll 26 in the conveyance direction.

The 9th guide roll 26 transfers the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the 8th guide roll 25 to the second heating roll ( 27) It is a rotating member that guides. The ninth guide roll 26 is disposed on the downstream side of the eighth guide roll 25 in the conveyance direction and on the upstream side of the second heating roll 27 in the conveyance direction.

The second heating roll 27 is a cylindrical member with a rotation axis for heating the transparent conductive layer 2. The second heating roll 27 conveys the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) along the peripheral surface of the second heating roll 27 . The second heating roll 27 is disposed on the downstream side of the ninth guide roll 26 in the conveyance direction and on the upstream side of the tenth guide roll 28 in the conveyance direction.

The tenth guide roll 28 winds the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the second heating roll 27 into a winding unit 9. It is a rotating member that guides. The ninth guide roll 26 is disposed on the downstream side in the conveyance direction of the second heating roll 27 and on the upstream side in the conveyance direction of the 11th guide roll 30 (described later).

The third chamber 29 is a casing that accommodates the 8th guide roll 25, the 9th guide roll 26, the 2nd heating roll 27, and the 10th guide roll 28. A vacuum unit is installed in the third chamber 29 to vacuum the interior.

[Winding unit]

The winding unit 9 is provided with an 11th guide roll 30, a winding roll 31, and a winding chamber 32. The winding unit 9 is arranged adjacent to the second anneal unit 8 on the downstream side of the second anneal unit 8 in the conveyance direction.

The eleventh guide roll 30 winds the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the second annealing unit 8 into a winding roll 31. It is a rotating member that guides. The eleventh guide roll 30 is disposed on the downstream side of the tenth guide roll 28 in the conveyance direction and on the upstream side of the take-up roll 31 in the conveyance direction.

The winding roll 31 is a cylindrical member having a rotation axis for winding the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)). The winding roll 31 is arranged at the most downstream of the film manufacturing apparatus 10 in the conveyance direction. A motor (not shown) for rotating the winding roll 31 is connected to the winding roll 31.

The winding chamber 32 is a casing that accommodates the eleventh guide roll 30 and the winding roll 31. A vacuum unit is installed in the winding chamber 32 to vacuum the interior.

<Method for producing transparent conductive film>

Next, an embodiment of a method for manufacturing the transparent conductive film 3 using the film manufacturing apparatus 10 will be described.

The method of manufacturing the transparent conductive film 3 forms a transparent conductive layer 2 on one side of the long substrate 1 in the thickness direction while conveying the long substrate 1 in the longitudinal direction.

In detail, the method of manufacturing the transparent conductive film 3 includes a first step of preparing a long base material 1, and forming a transparent conductive layer 2 on one side in the thickness direction of the long base material 1 under a vacuum atmosphere. It includes a second step and a third step of heating the transparent conductive layer 2 using a heating roll in a vacuum atmosphere.

Additionally, in this method, the first process, the second process, and the third process are performed in a roll-to-roll manner.

When the first process, the second process, and the third process are performed in a roll-to-roll method, productivity is excellent.

[First process]

In the first step, a long base material 1 is prepared.

Examples of the long substrate 1 include a long polymer film. Materials for the polymer film include, for example, olefin resin, polyester resin, (meth)acrylic resin (acrylic resin and/or methacrylic resin), polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, poly Amide resin, polyimide resin, cellulose resin, and polystyrene resin can be mentioned. Examples of olefin resins include polyethylene, polypropylene, and cycloolefin polymers. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of the (meth)acrylic resin include polymethacrylate. The material of the base material 1 is preferably polyester resin, and more preferably polyethylene terephthalate (PET).

The thickness of the long base material 1 is, for example, 10 μm or more, preferably 30 μm or more, and for example, 500 μm or less.

If the thickness of the long base material 1 is more than the above lower limit, transportability and handling are excellent.

If the thickness of the long base material 1 is below the above upper limit, productivity is excellent.

In addition, the length in the short direction (width direction length) of the long base material 1 is, for example, 100 mm or more, preferably 200 mm or more, and for example, 5000 mm or less, preferably 2000 mm or less.

Additionally, a functional layer may be disposed in advance on one side of the long substrate 1 in the thickness direction and/or on the other side in the thickness direction. When arranging a functional layer on one side of the long base material 1 in the thickness direction, for example, the transparent conductive film 3 is formed by combining the long base material 1, the functional layer, and the transparent conductive layer 2 with a thickness of Arrange them in order facing one side. In addition, when the functional layer is disposed on the other side of the long substrate 1 in the thickness direction, the transparent conductive film 3 is formed by attaching the functional layer, the long substrate 1, and the transparent conductive layer 2 to one side in the thickness direction. Prepared in order toward .

Examples of the functional layer disposed on one side of the long base material 1 in the thickness direction include a hard coat layer and an optical adjustment layer. Examples of the functional layer disposed on the other side of the long substrate 1 in the thickness direction include an anti-blocking layer.

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

The hard coat composition contains resin, and optionally particles.

Resins include, for example, curable resins and thermoplastic resins (for example, polyolefin resins), and curable resins are preferred. Examples of the curable resin include active energy ray curable resins that are cured by irradiation of active energy rays (specifically, ultraviolet rays, electron beams, etc.), and thermosetting resins that are cured by heating, preferably active energy rays. A curable resin may be mentioned. 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 group and (meth)acryloyl group (methacryloyl group and/or acryloyl group). Examples of the active energy ray-curable resin include (meth)acrylic ultraviolet ray-curable resin. Examples of (meth)acrylic ultraviolet curable resin include urethane acrylate and epoxy acrylate. Resins can be used alone or in combination of two or more types.

Examples of particles include inorganic particles and organic particles. Examples of inorganic particles include metal oxide particles and carbonate particles. Examples of metal oxide particles include zirconium oxide, titanium oxide, zinc oxide, and tin oxide. Examples of carbonate particles include calcium carbonate. Examples of organic particles include crosslinked acrylic resin particles. Particles can be used alone or in combination of two or more types.

Then, the hard coat composition is obtained by mixing the resin and particles mixed as necessary.

Additionally, known additives such as leveling agents, thixotropic agents, and antistatic agents can be added to the hard coat composition as needed.

To form a hard coat layer, a diluted solution of the hard coat composition is applied to one side in the thickness direction of the elongated base material 1, and after drying, the hard coat composition is cured by irradiation with ultraviolet rays.

This forms a hard coat layer.

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 is, for example, 10 μm or less, preferably 3 μm or less.

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

In this case, the transparent conductive film 3 obtained includes a long base material 1, a hard coat layer, and a transparent conductive layer 2 in that order.

The optical adjustment layer is used to suppress visibility of the pattern of the transparent conductive layer (2) or to ensure excellent transparency in the transparent conductive film (3) while suppressing reflection at the interface within the transparent conductive film (3). ) is a layer that adjusts the optical properties (for example, refractive index).

The optical adjustment layer is formed, for example, from an optical adjustment composition. The optical adjustment composition contains the above-described resin and the above-described particles. Resins include those listed in the hard coat composition. Examples of the particles include those listed in the hard coat composition.

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

The optical adjustment composition may also contain known additives such as leveling agents, thixotropic agents, antistatic agents, etc.

To form an optical adjustment layer, a diluted solution of the optical adjustment composition is applied to one surface in the thickness direction of the elongated base material 1, and after drying, the optical adjustment composition is cured by irradiation with ultraviolet rays.

This forms an optical adjustment layer.

From the viewpoint of scratch resistance, the thickness of the optical adjustment layer is, for example, 5 nm or more, preferably 10 nm or more, more preferably 50 nm or more, and also, for example, 500 nm or less, preferably 200 nm or less, more preferably Typically, it is less than 100 nm. The thickness of the optical adjustment layer can be measured by cross-sectional observation using, for example, a transmission electron microscope.

In this case, the transparent conductive film 3 obtained includes a long base material 1, an optical adjustment layer, and a transparent conductive layer 2 in that order.

The anti-blocking layer provides blocking resistance to each surface of a plurality of transparent conductive films 3 that are in contact with each other, such as when the transparent conductive films 3 are laminated in the thickness direction.

The material of the antiblocking layer is, for example, an antiblocking composition.

Examples of antiblocking compositions include mixtures described in Japanese Patent Application Laid-Open No. 2016-179686.

To form an anti-blocking layer, a diluted solution of the anti-blocking composition is applied to the other side in the thickness direction of the elongated substrate 1, and after drying, the anti-blocking composition is cured by irradiation with ultraviolet rays.

This forms an anti-blocking layer.

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

In this case, the transparent conductive film 3 obtained includes an anti-blocking layer, an elongated base material 1, and a transparent conductive layer 2 in that order.

One or two or more functional layers can be disposed on the long substrate 1, and preferably a hard coat layer is disposed on the long substrate 1 in advance.

Then, the long base material 1 is placed on the delivery roll 11. That is, the roll body in which the long base material 1 is wound into a roll shape is mounted on the delivery roll 11.

In this way, a long base material (1) is prepared.

[Second process]

In the second process, the transparent conductive layer 2 is formed on one side of the elongated base material 1 in the thickness direction under a vacuum atmosphere.

In the second process, first, the long base material 1 is transported in the longitudinal direction.

In order to convey the long substrate 1 in the longitudinal direction, the delivery roll 11 and the take-up roll 31 are driven to rotate by a motor, and the long substrate 1 is delivered from the delivery roll 11, and the first Guide roll (12), second guide roll (14), third guide roll (15), film forming roll (16), fourth guide roll (18), fifth guide roll (20), sixth guide roll (21) ), 1st heating roll (22), 7th guide roll (23), 8th guide roll (25), 9th guide roll (26), 2nd heating roll (27), 10th guide roll (28), and sequentially conveyed by the 11th guide roll 30 and wound by the winding roll 31.

As a result, the long base material 1 is conveyed in the conveyance direction from the delivery roll 11 to the take-up roll 31 in a roll-to-roll manner.

The conveyance speed is, for example, 0.5 m/min or more, preferably 1.4 m/min or more, preferably 2.0 m/min or more, and also, for example, 50 m/min or less, preferably 20 m/min or less. , more preferably 15 m/min or less.

Next, the transparent conductive layer 2 is formed on one side of the long substrate 1 in the thickness direction under a vacuum atmosphere while conveying the long substrate 1 in the longitudinal direction.

Specifically, the long base material 1 is conveyed while contacting the surface of the film forming roll 16 along the circumferential direction. Then, sputtering is performed on the transported long base material 1 in a vacuum atmosphere. That is, the sputter unit 6 is operated to form the transparent conductive layer 2 on the lower surface (one side) of the elongated base material 1.

Specifically, sputtering gas is supplied to the inside of the first chamber 19 under vacuum, and a voltage is applied to cause the gas to collide with the target 17. As a result, the target material thrown off from the target 17 adheres to the lower surface (one side) of the long substrate 1 conveyed from the upstream side of the conveyance direction on the sides and below the film deposition roll 16, making it transparent. A conductive layer 2 is formed.

That is, in this method, the transparent conductive layer 2 is formed by sputtering while conveying the long base material 1 along the peripheral surface of the film forming roll 16.

Examples of the sputtering gas include rare gases. Examples of noble gases include argon gas, krypton gas, and xenon gas.

Additionally, when forming the transparent conductive layer 2 by a sputtering method, atoms derived from the sputtering gas are taken into the transparent conductive layer 2. That is, the transparent conductive layer 2 contains atoms derived from the sputtering gas.

In the transparent conductive layer 2, the content of atoms derived from the sputtering gas is, for example, 0.5 atomic% or less, preferably 0.2 atomic% or less, more preferably 0.1 atomic% or less, and still more preferably 0.1 atomic% or less. It is less than atomic percent.

The lower limit of the content is the ratio corresponding to when the presence of atoms originating in the sputtering gas can be confirmed by a fluorescence X-ray analyzer, and is at least 0.0001 atomic% or more.

In addition, as a sputtering gas, a reactive gas (for example, oxygen gas) can be used together with the rare gas.

The flow rate of the reactive gas relative to the total amount of noble gas and reactive gas is, for example, 0.1 flow rate% or more, preferably 0.5 flow rate% or more, and for example, 5.0 flow rate% or less, preferably 4.0 flow rate% or less.

Additionally, the applied voltage (film formation voltage) is, for example, 0.5 W/mm or more, preferably 1.0 W/mm or more, and for example, 10 W/mm or less, preferably 7.0 W/mm or less.

The material of the target 17, that is, the material of the transparent conductive layer 2, is, for example, a metal oxide such as indium tin composite oxide and antimony tin composite oxide, for example, aluminum nitride, titanium nitride, tantalum nitride, and nitride. Metal nitrides such as chromium, gallium nitride, and composite nitrides thereof, for example, metals such as gold, silver, copper, nickel, and alloys thereof, and preferably indium tin composite oxide.

That is, the transparent conductive layer 2 preferably contains indium tin composite oxide as a main component.

If the transparent conductive layer 2 contains indium tin composite oxide as a main component, the specific resistance of the transparent conductive layer 2 can be lowered.

When using indium tin composite oxide as the material of the transparent conductive layer 2, the content ratio of tin oxide is, for example, 0.5% by mass or more, preferably 2% by mass or more, with respect to the total amount of tin oxide and indium oxide. Also, for example, it is 20 mass% or less, preferably 15 mass% or less.

If the content ratio of tin oxide is more than the above-described lower limit, lowering the resistance is promoted. If the tin oxide content is below the above upper limit, the transparent conductive layer 2 has excellent strength.

In addition, since the target material thrown from the target 17 is heated to, for example, 100°C or higher and 200°C or lower, excessive heating of the transparent conductive layer 2 is suppressed by the film forming roll 16 in this method. This can suppress crystallization of the transparent conductive layer 2.

In detail, the temperature of the film forming roll 16 is, for example, -20°C or higher, preferably -10°C or higher, and for example, 80°C or lower, preferably 30°C or lower, more preferably 0°C. It is as follows.

If the temperature of the film-forming roll 16 is above the lower limit or below the above upper limit, excessive heating of the transparent conductive layer 2 can be suppressed and crystallization of the transparent conductive layer 2 can be suppressed (amorphous transparent A conductive layer (2) can be obtained.).

[Third process]

In the third process, the transparent conductive layer 2 is heated in a vacuum atmosphere using the first heating roll 22 and the second heating roll 27 as heating rolls. Specifically, the transparent conductive layer 2 is heated by the first annealing unit 7 (first heating roll 22) and the second annealing unit 8 (second heating roll 27). That is, in this method, a part of the transparent conductive layer 2 is crystallized using the first annealing unit 7, and the remainder of the transparent conductive layer 2 is crystallized using the second annealing unit 8.

More specifically, the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) is conveyed while contacting the surface of the first heating roll 22 along the circumferential direction. Then, with respect to the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) to be transported, the transparent conductive layer ( 2) Heat. That is, the first anneal unit 7 is operated to crystallize the transparent conductive layer 2.

The temperature of the first heating roll 22 is, for example, 90°C or higher, preferably 100°C or higher, more preferably 150°C or higher, and also, for example, 200°C or lower, preferably 180°C or lower. .

The heating time (contact time of the first heating roll 22 with respect to the elongated substrate 1) in the first heating roll 22 is, for example, 0.25 seconds or more, preferably 10 seconds or more, and For example, it is 1 minute or less, preferably 0.75 minutes or less.

As a result, the transparent conductive layer 2 is crystallized (part of the transparent conductive layer 2 is crystallized).

Next, the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) is conveyed while contacting the surface of the second heating roll 27 along the circumferential direction. Then, with respect to the long base material 1 to be transported (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)), a transparent conductive layer ( 2) Heat. That is, the second anneal unit 8 is operated to crystallize the transparent conductive layer 2.

The temperature of the second heating roll 27 is, for example, 80°C or higher, preferably 100°C or higher, more preferably 150°C or higher, and also, for example, 200°C or lower, preferably 180°C or lower. . Preferably, the temperature of the first heating roll 22 and the temperature of the second heating roll 27 are the same.

The heating time (contact time of the second heating roll 27 with respect to the long base material 1) in the second heating roll 27 is, for example, 0.25 seconds or more, preferably 10 seconds or more, and For example, it is 1 minute or less, preferably 0.75 minutes or less. Preferably, the heating time in the first heating roll 22 and the heating time in the second heating roll 27 are the same.

The total heating time in the first heating roll 22 and the second heating roll 27 is, for example, 0.5 seconds or more, preferably 20 seconds or more, and, for example, 5 minutes or less, preferably. is less than 2 minutes, more preferably 1.5 minutes or less.

As a result, a transparent conductive film 3 is manufactured, which includes a long base material 1 and a transparent conductive layer 2 in that order in the thickness direction.

After that, the transparent conductive film 3 produced below the second heating roll 27 is wound around the winding roll 31 on the downstream side in the conveyance direction by the tenth guide roll 28 and the eleventh guide roll 30. is sent back toward

In the obtained transparent conductive film (3), the transparent conductive layer (2) is crystalline. If the transparent conductive layer 2 is crystalline, the specific resistance described later can be reduced.

In an example described later, whether the transparent conductive layer 2 is crystalline can be determined that the transparent conductive layer 2 is crystalline when the change rate of resistance value is 25% or less.

The thickness of the transparent conductive layer 2 is, for example, 10 nm or more, preferably 20 nm or more, more preferably 40 nm or more, further preferably 70 nm or more, particularly preferably 90 nm or more, and for example, 300 nm or more. or less, preferably 200 nm or less, more preferably 170 nm or less.

In addition, the thickness of the transparent conductive layer 2 can be measured by observing the cross section of the transparent conductive film 3 using, for example, a transmission electron microscope.

The specific resistance of the transparent conductive layer 2 is, for example, 4.5 x 10 ^-4 Ω·cm or less, preferably 3.0 x 10 ^-4 Ω·cm or less, more preferably 2.5 x 10 ^-4 Ω·cm or less, More preferably, it is 2.2×10 ^-4 Ω·cm or less, particularly preferably 2.0×10 ^-4 Ω·cm or less.

In addition, the specific resistance can be calculated by multiplying the surface resistance value measured by the four-terminal method in accordance with JIS K7194 by the thickness of the transparent conductive layer 2.

The surface resistance value of the transparent conductive layer 2 is, for example, 300 Ω/□ or less, preferably 250 Ω/□ or less, more preferably 120 Ω/□ or less, and even more preferably 50 Ω/□ or less.

The lower limit of the surface resistance value of the transparent conductive layer 2 is not particularly limited. For example, the surface resistance value of the transparent conductive layer 2 is usually more than 0 Ω/□ and more than 1 Ω/□.

Additionally, the surface resistance value can be measured by the four-terminal method based on JIS K7194.

<Action effect>

In the method of manufacturing the transparent conductive film 3, in the third step, the transparent conductive layer 2 is heated using the first heating roll 22 and the second heating roll 27 in a vacuum atmosphere to form a transparent conductive layer ( 2) is crystallized. Since the transparent conductive layer 2 is heated by a heating roll in a vacuum atmosphere, efficient heat transfer is possible through physical contact with the film, and the transparent conductive layer 2 can be crystallized in a shorter heating time. As a result, productivity can be improved.

On the other hand, in the case where the transparent conductive layer 2 cannot be sufficiently crystallized, in other words, if the transparent conductive layer 2 includes an amorphous portion, cracks may occur between the amorphous portion and the crystalline portion. However, in the transparent conductive film 3 obtained by this method, the occurrence of the above-mentioned cracks can be suppressed because the transparent conductive layer 2 is sufficiently crystallized.

<Variation example>

In the modified example, the same members and processes as in the one embodiment are given the same reference numerals, and detailed description thereof is omitted. In addition, the modified example can exhibit the same effects as the one embodiment, except as specifically mentioned. Additionally, one embodiment and modification examples can be appropriately combined.

In one embodiment, there is one target 17, but multiple targets may be placed.

In one embodiment, in the third process, the transparent conductive layer 2 is heated by the first heating roll 22 and the second heating roll 27, but the second heating roll 27 is not used. 1 The transparent conductive layer 2 can also be heated using only the heating roll 22. In this case, the entire transparent conductive layer 2 is crystallized using only the first heating roll 22. Additionally, other heating rolls (not shown) may be used together with the first heating roll 22 and the second heating roll 27.

In one embodiment, in the second process, the transparent conductive layer 3 can be formed on the transparent conductive layer 2 by using the first heating roll 22 as a film-forming roll. In this case, the entire transparent conductive layer 2 and 3 are crystallized using only the second heating roll 27.

Example

Examples and comparative examples are given below to illustrate the present invention in more detail. Additionally, the present invention is not limited to the examples and comparative examples in any way. In addition, specific values such as mixing ratio (content ratio), physical property values, parameters, etc. used in the following description are the corresponding mixing ratio (content ratio) described in the "Specific Details for Carrying out the Invention" above. ), physical property values, parameters, etc. can be replaced with the upper limit value (a numerical value defined as “less than” or “less than”) or a lower limit value (a numerical value defined as “above” or “exceeding”) of the corresponding description.

1. Preparation of transparent conductive film

<Example 1>

The film manufacturing apparatus 10 shown in FIG. 1 was used to manufacture the transparent conductive film.

[First process]

An ultraviolet curable resin containing an acrylic resin was applied to one side in the thickness direction of a PET film (thickness: 50 μm, manufactured by Toray Industries, Ltd.) as the long substrate 1 to form a coating film. Subsequently, the coating film was cured by ultraviolet irradiation. As a result, a hard coat layer (2 μm thick) was formed on one side of the long base material 1 in the thickness direction. Next, the long base material 1 was mounted on the delivery roll 11 as a roll body. In this way, a long base material (1) was prepared.

[Second process]

Next, the delivery roll 11 and the take-up roll 31 were rotationally driven by a motor to convey the long base material 1 in the longitudinal direction. At this time, the conveyance speed was 2.1 m/min.

Next, sputtering (reactive sputtering method) was performed in a vacuum atmosphere while transporting the long base material 1 in the longitudinal direction. That is, the sputter unit 6 was operated to form the transparent conductive layer 2 on the elongated substrate 1.

Sputtering conditions are as follows.

Sputtering power: DC power

Film formation output: 1.05W/mm

Horizontal magnetic field strength on target: 90mT

Sputtering gas: After evacuating the moisture pressure in the film formation room until it reaches 0.9×10 ^-4 Pa or less, supply argon gas (rare gas) and oxygen gas (reactive gas).

Flow rate of oxygen gas relative to the total amount of argon gas and oxygen gas: approximately 2.3 flow%

Pressure:0.4Pa

[target]

Sintered body of indium oxide and tin oxide (indium tin composite oxide with a tin oxide concentration of 10% by mass)

[Tabernacle Roll (16)]

Temperature:-5℃

[Third process]

The transparent conductive layer 2 was heated in a vacuum atmosphere while conveying the long substrate 1 (the long substrate 1 on which the transparent conductive layer 2 was laminated (formed)) in the longitudinal direction. That is, only the first anneal unit 7 was operated to heat the transparent conductive layer 2 and crystallize it.

Heating conditions are as follows.

[First heating roll (22)]

Temperature: 160℃, heating time: 1.4 minutes

As a result, a transparent conductive film (3) was obtained. Additionally, the thickness of the transparent conductive layer 2 was 150 nm.

<Example 2>

In the same procedure as in Example 1, a transparent conductive film (3) was obtained.

However, the thickness of the transparent conductive layer 2 was changed to 22 nm, and the conveyance speed was changed to 9.4 m/min. Additionally, in the third process, the first anneal unit 7 and the second anneal unit 8 were used.

In addition, as a target, a sintered body of indium oxide and tin oxide (indium tin composite oxide with a tin oxide concentration of 10% by mass) and a sintered body of indium oxide and tin oxide (indium tin composite oxide with a tin oxide concentration of 3.3% by mass) were used in combination. .

Additionally, the flow rate of oxygen gas relative to the total amount of argon gas and oxygen gas was changed to about 3.5 flow rate%.

<Example 3>

In the same procedure as in Example 2, a transparent conductive film (3) was obtained. However, the noble gas in the sputtering gas was changed to krypton gas.

<Comparative Example 1>

In the same procedure as in Example 1, a transparent conductive film (3) was obtained.

However, in the third step, the transparent conductive layer 2 was not heated with the first heating roll 22, but the transparent conductive layer 2 was heated using the infrared heater in the second chamber 24.

<Comparative Example 2>

In the same manner as in Example 3, a transparent conductive film (3) was obtained. However, in the third process, the transparent conductive layer 2 is not heated by the first heating roll 22 and the second heating roll 27, and the infrared rays in the second chamber 24 and the third chamber 29 are heated. The transparent conductive layer 2 was heated using a heater.

2. Evaluation

<Thickness of transparent conductive layer>

The thickness of the transparent conductive layer in each example and each comparative example was measured by FE-TEM observation. Specifically, first, samples for cross-sectional observation of each transparent conductive layer in each Example and each Comparative Example were produced by the FIB microsampling method. In the FIB micro-sampling method, a FIB device (brand name “FB2200”, manufactured by Hitachi) was used, and the acceleration voltage was set to 10 kV. Next, the thickness of the transparent conductive layer in the sample for cross-sectional observation was measured by FE-TEM observation. In FE-TEM observation, a FE-TEM device (brand name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200 kV. The results are shown in Table 1.

<Crystallinity of transparent conductive layer>

The resistance value (referred to as the resistance value before heating) of the transparent conductive layer in each example and each comparative example was measured. Next, the transparent conductive film was heated in a hot air oven at 140°C for 1 hour.

After that, the resistance value (referred to as the resistance value after heating) of the transparent conductive layer was measured. Next, the rate of change in resistance value was determined based on the following equation (1).

Rate of change in resistance value = (resistance value before heating - resistance value after heating) / resistance value before heating × 100 (1)

Additionally, the crystallinity of the transparent conductive layer was evaluated based on the following standards.

○ Change rate of resistance value is less than 25%

× Change rate of resistance value exceeds 25%

Table 1 shows the evaluation of the resistance value before heating, the resistance value after heating, the rate of change of resistance value, and the crystallinity of the transparent conductive layer.

Additionally, although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be construed as limiting. Modifications of the present invention apparent to those skilled in the art are included in the scope of the later claims.

(Industrial applicability)

The method for producing a transparent conductive film of the present invention is suitably used for producing a transparent conductive film, for example.

1 long article
2 Transparent conductive layer
3 Transparent conductive film
22 No. 1 heating roll
27 Second heating roll

Claims (2)

A first step of preparing a long-scale substrate,
a second step of forming a transparent conductive layer on one side of the substrate in the thickness direction under a vacuum atmosphere;
A method for producing a transparent conductive film comprising a third step of heating the transparent conductive layer using a heating roll in a vacuum atmosphere. According to claim 1,
A method of manufacturing a transparent conductive film in which the first process, the second process, and the third process are performed in a roll-to-roll method.