JP2024005996A - Production method of transparent conductive film - Google Patents

Abstract

To provide a production method of a transparent conductive film capable of forming a transparent conductive layer excellent in productivity.SOLUTION: A production method of a transparent conductive film 3 includes a first step for preparing a long-sized substrate 1, a second step for forming a transparent conductive layer 2 on one side in the thickness direction of the substrate 1 under vacuum atmosphere, and a third step for heating the transparent conductive layer 2 by using a heating roller 22 under vacuum atmosphere.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a transparent conductive film.

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

As such a method, for example, an amorphous transparent conductive layer is formed by sputtering in a vacuum atmosphere and in the presence of argon gas while conveying a long transparent film substrate using a roll-to-roll method. Then, in a vacuum atmosphere, the transparent film base material on which the amorphous transparent conductive layer is formed is heated with an infrared heater to crystallize the transparent conductive layer, thereby producing a transparent conductive film. has been proposed (for example, see Patent Document 1).

JP2016-056423A

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

An object of the present invention is to provide a method for manufacturing a transparent conductive film that can form a transparent conductive layer with excellent productivity.

The present invention [1] includes a first step of preparing a long base material, a second step of forming a transparent conductive layer on one side in the thickness direction of the base material under a vacuum atmosphere, and a second step of forming a transparent conductive layer on one side in the thickness direction of the base material under a vacuum atmosphere. , a third step of heating the transparent conductive layer using a heating roll.

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

In the method for manufacturing 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. Thereby, the transparent conductive layer can be sufficiently crystallized.

FIG. 1 shows a schematic diagram of an embodiment of a film manufacturing apparatus used in an embodiment of the method for manufacturing 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 base material 1 in the thickness direction while conveying the long base material 1 in the longitudinal direction. do.

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

<Film manufacturing equipment>
In FIG. 1, the left-right direction on the paper surface is the conveyance direction. The right side of the paper is the downstream side in the conveyance direction. The left side of the paper is the upstream side in the conveyance direction. Note that the conveyance direction is a conveyance direction between adjacent units, and is not a conveyance direction within each unit. The paper thickness direction is the width direction. The front side of the paper is one side in the width direction. The back side of the paper is the other side in the width direction. The up-down direction on the paper is the up-down direction. The upper side of the paper is the upper side. The lower side of the paper 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 delivery unit 5, a sputtering unit 6, a first annealing unit 7, a second annealing unit 8, and a winding unit 9.

[Sending 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 rotating shaft for delivering the elongated base material 1 . The delivery roll 11 is disposed at the most upstream position in the transport direction of the film manufacturing apparatus 10 . 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 elongated base material 1 sent out from the delivery roll 11 to the sputtering unit 6 . The first guide roll 12 is arranged downstream of the delivery roll 11 in the transport direction and upstream of the second guide roll 14 (described later) in the transport direction.

The delivery chamber 13 is a casing that accommodates the delivery roll 11 and the first guide roll 12. The delivery chamber 13 is provided with a vacuum unit that can evacuate the inside.

[Sputter unit]
The sputter unit 6 laminates (forms) the transparent conductive layer 2 on the elongated base material 1 conveyed from the delivery unit 5 by sputtering. The sputter unit 6 is arranged downstream of the delivery unit 5 in the transport direction and upstream of the first annealing unit 7 in the transport direction, so as to be adjacent thereto. 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 .

The second guide roll 14 is a rotating member that guides the long base material 1 conveyed from the delivery unit 5 (first guide roll 12) to the third guide roll 15. The second guide roll 14 is arranged downstream of the first guide roll 12 in the transport direction and upstream of the third guide roll 15 in the transport 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 arranged downstream of the second guide roll 14 in the transport direction and upstream of the film forming roll 16 in the transport direction.

The film forming roll 16 is a cylindrical member having a rotating shaft for laminating (forming) the transparent conductive layer 2 on the elongated base material 1 . The film forming roll 16 conveys the elongated base material 1 along the circumferential surface of the film forming roll 16 . The film forming roll 16 is arranged downstream of the third guide roll 15 in the transport direction and upstream of the fourth guide roll 18 in the transport direction.

The target 17 is made of a material containing atoms that constitute the transparent conductive layer 2 , and is preferably made of the material of the transparent conductive layer 2 . The target 17 is placed near the film forming roll 16. Specifically, the target 17 is disposed below the film-forming roll 16 and facing the film-forming roll 16 with an interval therebetween.

The fourth guide roll 18 guides the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the film forming roll 16 to the first annealing unit 7. It is a rotating member. The fourth guide roll 18 is arranged downstream of the film forming roll 16 in the transport direction and upstream of the fifth guide roll 20 (described later) in the transport direction.

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 . The first chamber 19 is provided with a vacuum unit that can vacuum the inside.

[First annealing unit]
The first annealing unit 7 heats the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the sputtering unit 6 to crystallize the transparent conductive layer 2. to become In other words, the first annealing unit 7 heats and crystallizes the transparent conductive layer 2. The first annealing unit 7 is arranged downstream of the sputtering unit 6 in the transport direction and upstream of the second annealing unit 8 in the transport direction so as to be adjacent thereto. The first annealing 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.

The fifth guide roll 20 guides the elongated base material 1 (the elongated base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the sputtering unit 6 (the fourth guide roll 18) into a sixth guide. It is a rotating member that guides the roll 21. The fifth guide roll 20 is arranged downstream of the fourth guide roll 18 in the transport direction and upstream of the sixth guide roll 21 in the transport direction.

The sixth guide roll 21 is a rotating member that guides the elongated base material 1 conveyed from the fifth guide roll 20 to the first heating roll 22. The sixth guide roll 21 is arranged downstream of the fifth guide roll 20 in the transport direction and upstream of the first heating roll 22 in the transport direction.

The first heating roll 22 is a cylindrical member having a rotating shaft for heating the transparent conductive layer 2 . The second heating roll 27 conveys the elongated base material 1 (the elongated 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 arranged downstream of the sixth guide roll 21 in the transport direction and upstream of the seventh guide roll 23 in the transport direction.

The seventh guide roll 23 guides the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the first heating roll 22 to the second annealing unit 8. It is a rotating member that rotates. The seventh guide roll 23 is arranged downstream of the first heating roll 22 in the transport direction and upstream of the eighth guide roll 25 (described later) in the transport direction.

The second chamber 24 is a casing that houses the fifth guide roll 20, the sixth guide roll 21, the first heating roll 22, and the seventh guide roll 23. The second chamber 24 is provided with a vacuum unit that can vacuum the inside.

[Second annealing unit]
The second annealing unit 8 heats the elongated base material 1 (the elongated base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the first annealing unit 7, and crystallize. In other words, the second annealing unit 8 heats and crystallizes the transparent conductive layer 2. Specifically, 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 annealing unit 8 is arranged downstream of the first annealing unit 7 in the transport direction and upstream of the winding unit 9 in the transport direction so as to be adjacent thereto.

The second annealing 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 .

The eighth guide roll 25 carries out the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) conveyed from the first annealing unit 7 (seventh guide roll 23). 9 is a rotating member that guides the guide roll 26. The eighth guide roll 25 is arranged downstream of the seventh guide roll 23 in the transport direction and upstream of the ninth guide roll 26 in the transport direction.

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

The second heating roll 27 is a cylindrical member having a rotating shaft for heating the transparent conductive layer 2 . The second heating roll 27 conveys the elongated base material 1 (the elongated base material 1 on which the transparent conductive layer 2 is laminated (formed)) along the circumferential surface of the second heating roll 27 . The second heating roll 27 is arranged downstream of the ninth guide roll 26 in the transport direction and upstream of the tenth guide roll 28 in the transport direction.

The tenth guide roll 28 guides 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 to the winding unit 9. It is a rotating member. The ninth guide roll 26 is arranged downstream of the second heating roll 27 in the transport direction and upstream of the eleventh guide roll 30 (described later) in the transport direction.

The third chamber 29 is a casing that accommodates the eighth guide roll 25, the ninth guide roll 26, the second heating roll 27, and the tenth guide roll 28. The third chamber 29 is provided with a vacuum unit that can vacuum the inside.
[Take-up unit]
The winding unit 9 includes an eleventh guide roll 30, a winding roll 31, and a winding chamber 32. The winding unit 9 is arranged downstream of the second annealing unit 8 in the transport direction and adjacent to the second annealing unit 8 .

The eleventh guide roll 30 rotates to guide 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 to the take-up roll 31. It is a member. The eleventh guide roll 30 is arranged downstream of the tenth guide roll 28 in the transport direction and upstream of the take-up roll 31 in the transport direction.

The winding roll 31 is a cylindrical member having a rotating shaft for winding up the elongated base material 1 (the elongated base material 1 on which the transparent conductive layer 2 is laminated (formed)). The take-up roll 31 is disposed at the most downstream position in the transport direction of the film manufacturing apparatus 10. A motor (not shown) for rotating the take-up roll 31 is connected to the take-up roll 31 .

The take-up chamber 32 is a casing that accommodates the eleventh guide roll 30 and the take-up roll 31. The winding chamber 32 is provided with a vacuum unit that can evacuate the inside.

<Method for producing transparent conductive film>
Next, one embodiment of a method for manufacturing the transparent conductive film 3 using the film manufacturing apparatus 10 will be described.

In the method for manufacturing the transparent conductive film 3, the transparent conductive layer 2 is formed on one surface of the long base material 1 in the thickness direction while the long base material 1 is conveyed in the longitudinal direction.

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

Moreover, in this method, the first step, the second step, and the third step are performed in a roll-to-roll method.

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

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

An example of the long base material 1 is a long polymer film. Examples of materials for the polymer film include olefin resin, polyester resin, (meth)acrylic resin (acrylic resin and/or methacrylic resin), polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, and polyimide. resins, cellulose resins, and polystyrene resins. Examples of olefin resins include polyethylene, polypropylene, and cycloolefin polymers. Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of the (meth)acrylic resin include polymethacrylate. The material for the base material 1 is preferably polyester resin, 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 elongated base material 1 is equal to or greater than the above-mentioned lower limit, it will be excellent in transportability and handling.

If the thickness of the elongated base material 1 is equal to or less than the above upper limit, productivity is excellent.

Further, the length in the lateral direction (length in the width direction) of the elongated 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.

Moreover, a functional layer can be arranged in advance on one thickness direction surface and/or the other thickness direction surface of the elongated base material 1. When a functional layer is arranged on one side in the thickness direction of the elongated base material 1, for example, the transparent conductive film 3 is arranged so that the elongated base material 1, the functional layer, and the transparent conductive layer 2 are arranged on one side in the thickness direction. Prepare in order toward one side. Further, when a functional layer is disposed on the other surface in the thickness direction of the elongated base material 1, the transparent conductive film 3 is arranged so that the functional layer, the elongated base material 1, and the transparent conductive layer 2 are arranged in the thickness direction. Prepare in order toward one side.

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

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

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

Examples of the resin include curable resins and thermoplastic resins (eg, polyolefin resins), and preferably curable resins. Examples of the curable resin include active energy ray-curable resins that are cured by irradiation with active energy rays (specifically, ultraviolet rays, electron beams, etc.) and thermosetting resins that are cured by heating. Examples include active energy ray-curable resins. Examples of active energy ray-curable resins include polymers having a functional group having a polymerizable carbon-carbon double bond in the molecule. Examples of such functional groups include vinyl groups and (meth)acryloyl groups (methacryloyl groups and/or acryloyl groups). Examples of active energy ray-curable resins include (meth)acrylic ultraviolet-curable resins. Examples of the (meth)acrylic ultraviolet curable resin include urethane acrylate and epoxy acrylate. The resins can be used alone or in combination of two or more.

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

Then, the hard coat composition is obtained by mixing the resin and optionally blended particles.

Further, the hard coat composition may contain known additives such as a leveling agent, a thixotropic agent, and an antistatic agent, if necessary.

To form the 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 ultraviolet irradiation.

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.

Note that 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 3 includes an elongated base material 1, a hard coat layer, and a transparent conductive layer 2 in this order.

The optical adjustment layer is made of a transparent material in order to suppress the visibility of the pattern of the transparent conductive layer 2, suppress reflection at the interface within the transparent conductive film 3, and ensure excellent transparency of the transparent conductive film 3. This layer adjusts the optical properties (for example, refractive index) of the conductive film 3.

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

The optical adjustment composition is then obtained by mixing the resin and particles.

The optical adjustment composition may further contain known additives such as a leveling agent, a thixotropic agent, and an antistatic agent.

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

This forms an optical adjustment layer.

The thickness of the optical adjustment layer is, from the viewpoint of scratch resistance, 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 , 100 nm or less. The thickness of the optical adjustment layer can be measured, for example, by observing a cross section using a transmission electron microscope.

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

The anti-blocking layer imparts anti-blocking properties to the respective surfaces of the plurality of transparent conductive films 3 that are in contact with each other when the transparent conductive films 3 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 elongated base material 1 in the thickness direction, and after drying, the anti-blocking composition is cured by UV irradiation.

This forms an anti-blocking layer.

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

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

One or more functional layers can be disposed on the elongated base material 1, and preferably, a hard coat layer is disposed on the elongated base material 1 in advance.

Then, the elongated base material 1 is placed on the delivery roll 11. That is, a roll body in which the elongated 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 step]
In the second step, a transparent conductive layer 2 is formed on one side of the elongated base material 1 in the thickness direction in a vacuum atmosphere.

In the second step, first, the long base material 1 is conveyed in the longitudinal direction.

To convey the long base material 1 in the longitudinal direction, the feed roll 11 and the take-up roll 31 are rotationally driven by a motor to feed the long base material 1 from the feed 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, first heating roll 22, seventh guide roll 23, eighth guide It is conveyed in order by the roll 25, the ninth guide roll 26, the second heating roll 27, the tenth guide roll 28, and the eleventh guide roll 30, and is wound up by the winding roll 31.

As a result, the elongated base material 1 is transported in the transport 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, for example, 50 m/min or less, preferably 20 m/min. The speed is preferably 15 m/min or less.

Next, the transparent conductive layer 2 is formed on one side of the elongated base material 1 in the thickness direction under a vacuum atmosphere while the elongated base material 1 is conveyed in the longitudinal direction.

Specifically, the elongated 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 elongated base material 1 being transported in a vacuum atmosphere. That is, the sputtering unit 6 is operated to form the transparent conductive layer 2 on the lower surface (one surface) of the elongated base material 1 .

Specifically, sputtering gas is supplied into the first chamber 19 under vacuum, and a voltage is applied to cause the gas to collide with the target 17 . As a result, on the sides and below the film-forming roll 16, the target material ejected from the target 17 is attached to the lower surface (one surface) of the elongated base material 1 conveyed from the upstream side in the conveyance direction, and the target material is made transparent. A conductive layer 2 is formed.

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

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

Furthermore, 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 Preferably it is less than 0.1 atomic %.

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

Further, as the sputtering gas, a reactive gas (for example, oxygen gas) can also be used in combination with the above-mentioned rare gas.

The flow rate of the reactive gas relative to the total amount of the rare gas and the reactive gas is, for example, 0.1% or more, preferably 0.5% or more, and, for example, 5.0% or less, preferably 4%. .0 flow% or less.

Further, the applied voltage (film forming 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. It is.

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 or antimony tin composite oxide, such as aluminum nitride, titanium nitride, tantalum nitride, chromium nitride, or gallium nitride. and metal nitrides such as composite nitrides thereof, such as metals such as gold, silver, copper, nickel, and alloys thereof, and preferably indium tin composite oxide.

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

When 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 indium tin composite oxide is used as the material for the transparent conductive layer 2, the content of tin oxide is, for example, 0.5% by mass or more, preferably 2% by mass, based on the total amount of tin oxide and indium oxide. The content is, for example, 20% by mass or less, preferably 15% by mass or less.

If the content rate of tin oxide is equal to or higher than the above-mentioned lower limit, lowering of resistance will be promoted. If the content rate of tin oxide is below the above-mentioned upper limit, the transparent conductive layer 2 will have excellent strength.

Further, since the target material ejected from the target 17 is heated to, for example, 100° C. or more and 200° C. or less, in this method, excessive heating of the transparent conductive layer 2 can be suppressed by the film forming roll 16. Suppresses crystallization of the transparent conductive layer 2.

Specifically, the temperature of the film forming roll 16 is, for example, -20°C or higher, preferably -10°C or higher, and also, for example, 80°C or lower, preferably 30°C or lower, and more preferably 0°C or lower. .

If the temperature of the film forming roll 16 is at least the above 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 conductive layer 2 ).

[Third step]
In the third step, 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 in the first annealing unit 7, and the remaining part of the transparent conductive layer 2 is crystallized in 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. be done. Then, a transparent conductive film is applied to the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) using the first heating roll 22 in a vacuum atmosphere. Heat layer 2. That is, the first annealing 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 in the first heating roll 22 (the contact time of the first heating roll 22 with the long base material 1) is, for example, 0.25 seconds or more, preferably 10 seconds or more, and, for example, 1 minute or less, Preferably, it is 0.75 minutes or less.

As a result, the transparent conductive layer 2 is crystallized (a portion 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, the long base material 1 (the long base material 1 on which the transparent conductive layer 2 is laminated (formed)) to be transported is coated with a transparent conductive material using the second heating roll 27 in a vacuum atmosphere. Heat layer 2. That is, the second annealing 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 in the second heating roll 27 (the contact time of the second heating roll 27 with the long base material 1) is, for example, 0.25 seconds or more, preferably 10 seconds or more, and, for example, 1 minute or less, Preferably, it is 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 also, for example, 5 minutes or less, preferably less than 2 minutes, more preferably is 1.5 minutes or less.

As a result, a transparent conductive film 3 including an elongated base material 1 and a transparent conductive layer 2 in this order in the thickness direction is manufactured.

Thereafter, the transparent conductive film 3 produced below the second heating roll 27 is transported by the tenth guide roll 28 and the eleventh guide roll 30 toward the take-up roll 31 on the downstream side in the transport direction.

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 below can be reduced.

The transparent conductive layer 2 can be determined to be crystalline if the rate of change in resistance value is 25% or less in Examples described later.

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, even more preferably 70 nm or more, particularly preferably 90 nm or more, and, for example, 300 nm or less, preferably, It is 200 nm or less, more preferably 170 nm or less.

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

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

Note that the specific resistance can be calculated by multiplying the surface resistance value measured by the four-probe method and the thickness of the transparent conductive layer 2 in accordance with JIS K7194.

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, still 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 0Ω/□, or more than 1Ω/□.

Note that the surface resistance value can be measured by a four-terminal method in accordance with JIS K7194.

<Effect>
In the method for manufacturing the transparent conductive film 3, in the third step, the transparent conductive layer 2 is heated in a vacuum atmosphere using the first heating roll 22 and the second heating roll 27 to crystallize the transparent conductive layer 2. to become 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, if the transparent conductive layer 2 cannot be sufficiently crystallized, in other words, if the transparent conductive layer 2 includes an amorphous part, cracks will occur between the amorphous part and the crystalline part. Sometimes. However, in the transparent conductive film 3 obtained by this method, since the transparent conductive layer 2 is sufficiently crystallized, the occurrence of the above-mentioned cracks can be suppressed.

<Modified example>
In the modified example, the same reference numerals are given to the same members and steps as in the embodiment, and detailed description thereof will be omitted. Moreover, the modified example can have the same effects as the one embodiment except as otherwise specified. Furthermore, one embodiment and the modified examples can be combined as appropriate.

In one embodiment, there is one target 17, but a plurality of targets 17 may be arranged.

In one embodiment, in the third step, 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 and only the first heating roll 22 is used. , the transparent conductive layer 2 can also be heated. In such a case, only the first heating roll 22 is used to crystallize the entire transparent conductive layer 2. Moreover, another heating roll (not shown) can also be used together with the first heating roll 22 and the second heating roll 27.

In one embodiment, the transparent conductive layer 3 can also be formed on the transparent conductive layer 2 in the second step using the first heating roll 22 as a film forming roll. In such a case, only the second heating roll 27 is used to crystallize both the transparent conductive layer 2 and the transparent conductive layer 3.

Examples and Comparative Examples are shown below to further specifically explain the present invention. Note that the present invention is not limited to the Examples and Comparative Examples. In addition, the specific numerical values of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description are the corresponding blending ratios ( Substitute with the upper limit value (value defined as "less than" or "less than") or lower limit value (value defined as "more than" or "exceeding") of the relevant description, such as content percentage), physical property value, parameter, etc. be able to.

1. Production of transparent conductive film <Example 1>
A film manufacturing apparatus 10 shown in FIG. 1 was used to manufacture the transparent conductive film.
[First step]
An ultraviolet curable resin containing an acrylic resin was applied to one side in the thickness direction of a PET film (50 μm thick, manufactured by Toray Industries, Inc.) serving as a long base material 1 to form a coating film. Next, the coating film was cured by ultraviolet irradiation. As a result, a hard coat layer (thickness: 2 μm) was formed on one side of the elongated base material 1 in the thickness direction. Next, the elongated base material 1 was mounted on a delivery roll 11 as a roll body. In this way, a long base material 1 was prepared.

[Second step]
Next, the delivery roll 11 and the take-up roll 31 were rotated 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 conveying 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 base material 1 .

The sputtering conditions are as follows.
Sputtering power supply: DC power supply Film forming output: 1.05W/mm
Horizontal magnetic field strength on target: 90mT
Sputtering gas: After evacuating the film forming chamber until the water pressure reaches 0.9×10 ^-4 Pa or less, supply argon gas (rare gas) and oxygen gas (reactive gas) Total amount of argon gas and oxygen gas Oxygen gas flow rate: approx. 2.3% flow rate
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)
[Film forming roll 16]
Temperature: -5℃

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

The heating conditions are as follows.
[First heating roll 22]
Temperature: 160℃, heating time: 1.4 minutes

Through the above steps, a transparent conductive film 3 was obtained. Note that the thickness of the transparent conductive layer 2 was 150 nm.

<Example 2>
A transparent conductive film 3 was obtained in the same manner as in Example 1.

However, the thickness of the transparent conductive layer 2 was changed to 22 nm, and the transport speed was changed to 9.4 m/min. Furthermore, in the third step, the first annealing unit 7 and the second annealing unit 8 were used.

In addition, as targets, we used 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 (tin oxide concentration of 3.3% by mass). (indium tin composite oxide).

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

<Example 3>
A transparent conductive film 3 was obtained in the same manner as in Example 2. However, the rare gas in the sputtering gas was changed to krypton gas.

<Comparative example 1>
A transparent conductive film 3 was obtained in the same manner as in Example 1.

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

<Comparative example 2>
A transparent conductive film 3 was obtained in the same manner as in Example 3. However, in the third step, the transparent conductive layer 2 is not heated by the first heating roll 22 and the second heating roll 27, but is heated using the infrared heaters in the second chamber 24 and the third chamber 29. 2 was heated.

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 prepared by the FIB microsampling method. In the FIB microsampling method, an FIB device (trade 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 the FE-TEM observation, an FE-TEM device (trade 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 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. Thereafter, the resistance value (referred to as post-heating resistance value) of the transparent conductive layer was measured. Next, the rate of change in resistance value was determined based on the following formula (1).
Rate of change in resistance value = (resistance value before heating - resistance value after heating) / resistance value before heating × 100 (1)
Further, the crystallinity of the transparent conductive layer was evaluated based on the following criteria.
〇 The rate of change in resistance value is 25% or less × The rate of change in resistance value exceeds 25% The table shows the resistance value before heating, the resistance value after heating, the rate of change in resistance value, and the evaluation of crystallinity of the transparent conductive layer. Shown in 1.

1 Long base material 2 Transparent conductive layer 3 Transparent conductive film 22 First heating roll 27 Second heating roll

< Comparative example 3 >
A transparent conductive film 3 was obtained in the same manner as in Example 1.

< Comparative example 4 >
A transparent conductive film 3 was obtained in the same manner as in Comparative Example 3 . However, the rare gas in the sputtering gas was changed to krypton gas.

<Comparative example 2>
A transparent conductive film 3 was obtained in the same manner as in Comparative Example 4 . However, in the third step, the transparent conductive layer 2 is not heated by the first heating roll 22 and the second heating roll 27, but is heated using the infrared heaters in the second chamber 24 and the third chamber 29. 2 was heated.

Claims (2)

A first step of preparing a long base material;
a second step of forming a transparent conductive layer on one side in the thickness direction of the base material in a vacuum atmosphere;
A method for manufacturing a transparent conductive film, comprising: a third step of heating the transparent conductive layer using a heating roll in a vacuum atmosphere. The method for producing a transparent conductive film according to claim 1, wherein the first step, the second step, and the third step are performed in a roll-to-roll method.

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