JP7615234B1 - Manufacturing method of laminated film - Google Patents

Abstract

The present invention provides a method for producing a laminated film, which is capable of producing a laminated film having an inorganic layer on a base film and having good optical properties.
[Solution] The method for producing a laminated film of the present invention includes a plasma treatment step S2 in which a first surface 10a of a substrate film 10 is plasma-treated in a reduced pressure atmosphere in a chamber, and a film formation step S3 in which an inorganic layer 20 is formed on the first surface 10a in a reduced pressure atmosphere following the plasma treatment step S2. The plasma treatment is a treatment using inductively coupled plasma of an argon-containing gas generated by application of high-frequency power to a low-inductance antenna. In the plasma treatment step S2, the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 to 900 nm in the plasma emission is set to 811 to 812 nm, and the ratio of the emission peak intensity _{I2 in the wavelength range of 603 to 604 nm to the emission peak intensity I1 in} the wavelength range of 706 to 707 nm is set to 0.50 or less.
[Selected Figure] Figure 1

Description

The present invention relates to a method for manufacturing a laminated film.

In order to reduce the weight and improve the functionality of electronic products, various composite materials that combine organic and inorganic materials have been developed. For example, a laminate film that includes a base film made of an organic material and an inorganic layer on the base film is known as a composite material. In the manufacturing process of the laminate film, for example, before the inorganic layer is formed on the base film, the surface of the base film is plasma treated to remove dirt and moisture from the surface. Removal of dirt and moisture from the surface of the base film helps to improve the adhesion of the inorganic layer formed on the surface to the base film. Technology related to plasma treatment of base films is described, for example, in Patent Document 1 below.

JP 2008-31521 A

Patent Document 1 describes a capacitively coupled plasma treatment of a substrate film. The treatment is carried out by a specified plasma treatment device. The plasma treatment device includes a vacuum chamber, a cathode electrode, and an anode electrode. The cathode electrode and the anode electrode are disposed in the vacuum chamber. The electrodes face each other with a gap between them. The electrodes are made of a metal such as stainless steel. With an argon-containing gas supplied to the vacuum chamber, high-frequency power is applied between the cathode electrode and the anode electrode, and argon is ionized between the electrodes into argon ions and electrons to generate argon plasma. In the plasma treatment of Patent Document 1, with argon plasma thus generated between the cathode electrode and the anode electrode, the substrate film as the object to be treated is passed between the electrodes.

Specifically, in capacitively coupled plasma processing, argon ions are attracted to the cathode electrode by a bias voltage generated between the electrodes, collide with it at high speed, bounce off the cathode electrode, and collide with the substrate film placed on the anode electrode. This type of plasma processing is conventionally called, for example, ion bombardment processing. In capacitively coupled plasma processing (ion bombardment processing), the kinetic energy of the argon ions in the plasma can be increased by increasing the bias voltage generated between the electrodes. The higher the kinetic energy of the argon ions colliding with the substrate film, the easier it is to remove dirt and moisture from the surface of the substrate film.

However, if the kinetic energy of the argon ions in the plasma is too high, metal components are expelled from the cathode electrode when the argon ions collide with the cathode electrode (sputtering effect). At least a portion of the metal components adhere to the surface of the base film. The metal components that adhere to the surface of the base film affect the optical properties of the base film. Furthermore, the higher the kinetic energy of the argon ions colliding with the base film, the more likely it is that the surface of the base film made of an organic material will be altered. This alteration also affects the optical properties of the base film.

The present invention provides a method for producing a laminated film that has an inorganic layer on a base film and has good optical properties.

The present invention [1] is a method for producing a laminated film, comprising: a preparation step of preparing a long base film having a first surface and a second surface opposite to the first surface; a plasma treatment step of plasma treating the first surface of the base film in a reduced pressure atmosphere in a chamber; and a deposition step of forming an inorganic layer on the first surface in a reduced pressure atmosphere subsequent to the plasma treatment step, wherein in the plasma treatment step, the plasma treatment is a treatment with inductively coupled plasma of an argon-containing gas generated by application of high frequency power to a low inductance antenna, and the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in the plasma emission is set to 811 nm to 812 nm, and the ratio of the emission peak intensity _I2 in the wavelength range of 603 nm to 604 nm to the emission peak intensity _I1 in the wavelength range of 706 nm to 707 nm is set to 0.50 or less.

The present invention [2] includes the method for producing a laminated film described in [1] above, in which, in the plasma treatment step, the base film is conveyed in the chamber while being cooled or heated by a roller with a temperature control function that contacts the base film.

The present invention [3] includes the method for manufacturing a laminated film described in [1] or [2] above, in which the low inductance antenna has a coil shape or an open loop shape.

The present invention [4] includes the method for producing a laminated film according to any one of the above [1] to [3], wherein in the plasma treatment step, the plasma current density at an intermediate position between the low inductance antenna and the base film is 1.0 mA/cm3 or ^more and 10 mA/ ^cm3 or less.

The present invention [5] includes the method for producing a laminated film according to any one of [1] to [4] above, in which the inorganic layer is formed by a sputtering method, a deposition method, or a chemical vapor deposition method in the film formation step.

The present invention [6] includes the method for producing a laminated film according to any one of the above [1] to [5], in which a conductive layer is formed as the inorganic layer in the film-forming step.

The present invention [7] includes the method for producing a laminated film according to any one of the above [1] to [5], in which an anti-reflection layer is formed as the inorganic layer in the film-forming step, and the anti-reflection layer includes a plurality of transparent inorganic oxide films laminated in the thickness direction.

In the method for manufacturing a laminated film of the present invention, as described above, in the plasma treatment process for the first surface of the substrate film under a reduced pressure atmosphere, a treatment is carried out using inductively coupled plasma of an argon-containing gas, which is generated by applying high-frequency power to a low-inductance antenna. This type of plasma treatment can achieve a higher plasma current density than the above-mentioned capacitively coupled plasma treatment. The higher the plasma current density, the more dirt and moisture can be removed from the first surface. The removal of dirt and moisture helps to increase the adhesion of the inorganic layer formed on the first surface in the film formation process to the first surface (substrate film). The removal of dirt and moisture also helps to ensure the original optical properties of the substrate film.

In the plasma treatment step, as described above, the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in the plasma emission is set to be within 811 nm to 812 nm, and the ratio (I2/ _I1 ) of the emission peak intensity _I2 within a wavelength range of 603 nm to 604 nm to the emission peak intensity _I1 within a wavelength range of 706 nm to ₇₀₇ nm is set to be 0.50 or less. By adjusting the plasma emission intensity in this way in the plasma treatment step, the kinetic energy of argon particles in the plasma can be suppressed. This makes it possible to suppress deterioration of the surface of the base film exposed to the plasma. This makes it possible to suppress changes in the optical properties of the base film.

In addition, in the film formation process after the plasma treatment process, as described above, an inorganic layer is formed on the first surface of the substrate film in a reduced pressure atmosphere following the plasma treatment process. That is, the substrate film is not placed under atmospheric pressure between the plasma treatment process and the film formation process. This type of film formation process can prevent foreign matter from being mixed in between the substrate film and the inorganic layer. This is useful for producing a laminate film with good optical properties.

Therefore, the laminated film manufacturing method of the present invention can produce a laminated film that has an inorganic layer on a base film and has good optical properties.

FIG. 1 is a process diagram of one embodiment of a method for producing a laminated film of the present invention. FIG. 2 is a schematic cross-sectional view of an example of a laminated film produced by the production method shown in FIG. 1 . 2 shows an example of a base film prepared in the preparation step shown in FIG. 1 . 1 is a schematic diagram of an apparatus for carrying out a plasma treatment step and a film formation step in one embodiment of the method for producing a laminated film of the present invention. 5 is a perspective view showing the positional relationship between a low inductance antenna and a base film in the plasma processing chamber shown in FIG. 4. 5 is a cross-sectional view showing the positional relationship between a low inductance antenna and a base film in the plasma processing chamber shown in FIG. 4. Fig. 5 is a schematic diagram of a modified example of the apparatus shown in Fig. 4. In this modified example, the plasma processing chamber does not include a roller with a temperature control function.

As shown in FIG. 1, a method for manufacturing a laminated film according to one embodiment of the present invention includes a preparation step S1, a plasma treatment step S2, and a film formation step S3. This manufacturing method produces a laminated film X shown in FIG. 2. The laminated film X includes a base film 10 and an inorganic layer 20. The inorganic layer 20 is disposed on one side of the base film 10 in the thickness direction H. In this embodiment, the base film 10 and the inorganic layer 20 are in contact with each other. The laminated film X extends in a direction (plane direction D) perpendicular to the thickness direction H. The laminated film X is, for example, an anti-reflective film or a transparent conductive film. The laminated film X may be another type of film. The laminated film X is an example of a laminated film manufactured by the laminated film manufacturing method of the present invention.

In this manufacturing method, first, in the preparation step S1, a long base film 10 is prepared as shown in FIG. 3. The base film 10 has a first surface 10a and a second surface 10b opposite to the first surface 10a. The length of the base film 10 is, for example, 1 m or more and, for example, 10,000 m or less. The width of the base film 10 is, for example, 1 cm or more and, for example, 500 cm or less.

In this embodiment, the base film 10 includes a resin film 11 and a cured resin layer 12 in this order in the thickness direction H. In this embodiment, the resin film 11 and the cured resin layer 12 are in contact with each other. In the base film 10, the cured resin layer 12 forms the first surface 10a, and the resin film 11 forms the second surface 10b.

The resin film 11 is an element that ensures the strength of the laminated film X. The resin film 11 is, for example, a transparent resin film having flexibility. Examples of the material of the resin film 11 include polyester resin, polyolefin resin, cellulose resin, acrylic resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, and polystyrene resin. Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of the polyolefin resin include polyethylene, polypropylene, and cycloolefin polymer (COP). Examples of the cellulose resin include triacetyl cellulose (TAC). These materials may be used alone or in combination of two or more. From the viewpoint of transparency and strength, the material of the resin film 11 is preferably at least one selected from the group consisting of polyester resin, polyolefin resin, and cellulose resin, and more preferably at least one selected from the group consisting of PET, COP, and TAC.

The thickness of the resin film 11 is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more, and is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. When the thickness of the resin film 11 is equal to or greater than the above lower limit, the strength of the laminated film X can be ensured. When the thickness of the resin film 11 is equal to or less than the above upper limit, the handleability of the base film 10 in the roll-to-roll process described below can be ensured. In addition, a carrier film may be attached to the second surface 10b of the resin film 11 in order to ensure the transportability and handleability of the base film 10 in the roll-to-roll process.

The total light transmittance (JIS K 7375-2008) of the resin film 11 is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more, and is, for example, 100% or less. When the total light transmittance of the resin film 11 is equal to or greater than the above lower limit, good transparency can be ensured in the laminate film X.

The cured resin layer 12 is a functional layer containing a resin. Specifically, the cured resin layer 12 is a cured product of a curable resin composition containing a curable resin. The cured resin layer 12 may further contain particles. That is, the cured resin layer 12 may be a cured product of a curable resin composition containing a curable resin and particles. Examples of the functional layer include a hard coat layer, an easy adhesion layer, and an anti-blocking (AB) layer. The hard coat layer is a layer that makes it difficult for scratches to form on the exposed surface (upper surface in FIG. 2) of the inorganic layer 20. The easy adhesion layer is a layer that enhances the adhesion of a layer formed on the base film 10 (in this embodiment, the inorganic layer 20) to the base film 10. The AB layer is a layer that has an anti-blocking property that suppresses sticking between adjacent films in the radial direction in a roll of the laminated film X. The cured resin layer 12 as the AB layer contains particles to express the anti-blocking property. The cured resin layer 12 as a hard coat layer and the cured resin layer 12 as an easy-adhesion layer may have anti-blocking properties by containing particles.

Examples of the curable resin include polyester resin, acrylic urethane resin, acrylic resin (excluding acrylic urethane resin), urethane resin (excluding acrylic urethane resin), amide resin, silicone resin, epoxy resin, and melamine resin. These curable resins may be used alone or in combination of two or more kinds. From the viewpoint of ensuring the hardness of the cured resin layer 12, the curable resin is preferably at least one selected from the group consisting of acrylic urethane resin and acrylic resin.

Examples of the curable resin include ultraviolet-curable resin and thermosetting resin. The curable resin is preferably an ultraviolet-curable resin. When the curable resin is an ultraviolet-curable resin, the curable resin can be cured without high temperature heating, which improves the manufacturing efficiency of the laminated film X.

Examples of the particles include inorganic oxide particles and organic particles. Examples of the materials for the inorganic oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of the materials for the organic particles include polymethyl methacrylate, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate. The particles are preferably inorganic oxide particles, and more preferably at least one selected from silica particles and zirconia particles.

The thickness of the cured resin layer 12 is preferably 0.5 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more, and is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. When the thickness of the cured resin layer 12 is equal to or greater than the above lower limit, the function of the cured resin layer 12 can be ensured. Specifically, when the cured resin layer 12 is a hard coat layer, the scratch resistance of the inorganic layer 20 can be ensured, when the cured resin layer 12 is an AB layer, the above anti-blocking property can be ensured, and when the cured resin layer 12 is an easy-adhesion layer, the adhesion of the inorganic layer 20 to the substrate film 10 can be ensured. When the thickness of the cured resin layer 12 is equal to or less than the above upper limit, the transparency of the cured resin layer 12 can be ensured.

The total light transmittance (JIS K 7375-2008) of the base film 10 is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more, and is, for example, 100% or less. When the total light transmittance of the base film 10 is equal to or greater than the above lower limit, good transparency can be ensured in the laminate film X.

The substrate film 10 can be produced by forming a cured resin layer 12 on a resin film 11. The cured resin layer 12 can be formed by applying the curable resin composition to the resin film 11 to form a coating film, and then curing the coating film. The curable resin composition may contain other components other than the curable resin and particles as necessary. Examples of the other components include a solvent and a leveling agent. Examples of the solvent include butyl acetate, ethyl acetate, toluene, and cyclopentanone. When the curable resin composition contains an ultraviolet-curable resin as the curable resin group, the curable resin composition preferably contains a photopolymerization initiator. When the curable resin composition contains a thermosetting resin as the curable resin, the curable resin composition preferably contains a thermal polymerization initiator.

When the curable resin composition contains a solvent, the coating on the resin film 11 is dried after the curable resin composition is applied. The drying temperature is, for example, 50°C or higher and, for example, 120°C or lower. The drying time is, for example, 10 seconds or longer and, for example, 10 minutes or shorter.

When the curable resin composition contains an ultraviolet-curable resin, the coating film on the resin film 11 is cured by ultraviolet irradiation. Examples of the light source for ultraviolet irradiation include a high-pressure mercury lamp and an LED light. The cumulative irradiation amount of the ultraviolet light is, for example, 100 mJ/ ^cm2 or more and, for example, 500 mJ/cm2 ^or less.

When the curable resin composition contains a thermosetting resin, the coating on the resin film 11 is cured by heating. The heating temperature is, for example, 100°C or higher and, for example, 150°C or lower. The heating time is, for example, 10 seconds or higher and, for example, 10 minutes or shorter.

In this manner, a long base film 10 can be produced. In this embodiment, a roll of the long base film 10 is prepared. Specifically, the base film 10 is wound so that the first surface 10a of the base film 10 faces inward in the radial direction of the roll.

In this manufacturing method, the substrate film 10 is then transported as the workpiece film W in a roll-to-roll manner under reduced pressure while the plasma treatment process S2 and the film formation process S3 are carried out in sequence. The device Y shown in FIG. 4 is an example of a device for carrying out the plasma treatment process S2 and the film formation process S3. The device Y includes a payout chamber R1, a winding chamber R2, a connection chamber C1, a plasma treatment chamber C2, a connection chamber C3, a film formation chamber C4, a connection chamber C5, a connection chamber C6, and a PEM device (not shown).

The unwinding chamber R1 is equipped with a unwinding roller 51 for unwinding the work film W. A roll of a long base film 10 is attached to the unwinding roller 51 as the work film W. In addition, a predetermined number of guide rollers G for guiding the work film W are provided in the unwinding chamber R1.

The winding chamber R2 is equipped with a winding roller 52 for winding up the work film W. A predetermined number of guide rollers G for guiding the work film W are provided within the winding chamber R2.

The connection chamber C1 is disposed next to the unwinding chamber R1 in the running direction of the workpiece film W, and is disposed before the plasma processing chamber C2. A predetermined number of guide rollers G for guiding the workpiece film W are provided inside the connection chamber C1. The connection chamber C1 is connected to a vacuum pump (not shown), and is configured so that the pressure inside the chamber can be adjusted. When the device Y is in operation, the pressure inside the connection chamber C1 is maintained at a predetermined pressure between the pressure inside the unwinding chamber R1 and the pressure inside the plasma processing chamber C2. This ensures a pressure difference between the unwinding chamber R1 and the plasma processing chamber C2.

The plasma processing chamber C2 is disposed between the connection chamber C1 and the connection chamber C3 in the running direction of the workpiece film W. In the plasma processing chamber C2, the plasma processing step S2 is carried out as described below.

In this embodiment, the plasma processing chamber C2 is equipped with multiple low inductance antennas (LA) 71. A low inductance antenna is an antenna that has a low inductance of 7.5 μH or less and can generate inductively coupled plasma by applying high frequency power. In this embodiment, the LA 71 is supported by a mounting fixture 72 and covered by a cover block 73 (not shown in FIG. 5) as shown in FIG. 5 and FIG. 6, and is placed inside the plasma processing chamber C2 (an example is shown in which the number of LA 71 is four).

The multiple LAs 71 are aligned in the running direction of the base film 10 and in the direction perpendicular to the running direction (the width direction of the base film 10). The fixture 72 is a vacuum flange. As shown in FIG. 6, the LAs 71 are fixed to the fixture 72 via a field through 74. As shown in FIG. 4, the fixture 72 is assembled to an opening 75 provided in the wall of the plasma processing chamber C2. Specifically, the fixture 72 is assembled to the opening 75 with a seal member (not shown) sandwiched between the wall of the plasma processing chamber C2 and the fixture 72. The LAs 71 are electrically connected to a high-frequency power source (RF power source) outside the plasma processing chamber C2 via an impedance matching device. Such LAs 71 are formed of a conductor. Examples of the conductor include copper and silver, and copper is preferable. The LAs 71 may be covered with an insulator. Examples of the insulator include glass and quartz.

The cover block 73 comprises a block body 73A and a plurality of partition plates 73B. The block body 73A has a plurality of storage spaces 73a. Each storage space 73a stores one LA 71. The partition plates 73B are arranged to close the storage spaces 73a. The storage spaces 73a are sealed spaces. In the cover block 73, the block body 73A is made of, for example, aluminum. Examples of aluminum include aluminum A5052. The partition plates 73B are made of an insulating material. Examples of insulating materials include quartz and glass. The separation distance d' (shown in FIG. 6) between the substrate film 10 traveling in the plasma processing chamber C2 and the cover block 73 is, for example, 50 to 200 mm. Such a cover block 73 helps to avoid damage and contamination of the LA71 due to plasma treatment without excessively reducing the plasma conversion efficiency due to the power applied to the LA71, and also helps to suppress damage to the substrate film 10 being plasma treated.

As shown in FIG. 5, the LA 71 has an open loop shape in this embodiment. The open loop shape of the LA 71 is advantageous in lowering the inductance of the LA 71. Therefore, the open loop LA 71 can suppress the increase in voltage due to the increase in the power applied to the LA 71. This can suppress abnormal discharge during the plasma treatment described below. The suppression of abnormal discharge can suppress damage to the base film 10 to be plasma treated. Specifically, the LA 71 has a U-shape having two free ends. For each LA 71, the two free ends are fixed to the mounting fixture 72 so as to be aligned in the width direction of the base film 10. In addition, in this embodiment, the LA 71 has an extension portion 71a on the opposite side to the two free ends. The extension portion 71a extends parallel to the base film 10 passing through the plasma treatment chamber C2. The extension portion 71a extends in the width direction of the base film 10. Each extension 71a may extend in the running direction of the base film 10 (four LAs 71 may be arranged in this manner). The length of the extension 71a is, for example, 50 to 150 mm (FIG. 5 illustrates an example in which the length of the extension 71a is the same as the maximum length _d2 of the LA 71, which will be described later). The LA 71 may have a coil shape instead of an open loop shape.

The LA 71 extends from the fixture 72 toward the base film 10. The LA 71 preferably extends perpendicularly to the fixture 72. The extension length d ₁ of the LA 71 from the fixture 72 is, for example, 30 to 150 mm. The maximum length d ₂ of the LA 71 in the surface direction of the base film 10 is, for example, 50 to 150 mm. The separation distance d ₃ (shown in FIG. 6 ) between the LA 71 and the base film 10 is, for example, 50 to 200 mm. The extension length d ₁ and the separation distance d ₃ are preferably the same. The ratio (d ₃ /d ₁ ) of the separation distance d ₃ to the extension length d ₁ is, for example, 0.5 to 3.5. The number (number of rows) of the LAs 71 spaced apart in the running direction of the base film 10 may be 1, 2, or 3, or may be 4 or more if necessary, depending on the running speed (i.e., plasma treatment time) of the base film 10. In the running direction of the base film 10, the center-to-center distance d ₄ between adjacent LAs 71 is, for example, 100 to 500 mm. In the width direction of the base film 10, the center-to-center distance d ₅ between adjacent LAs 71 is, for example, 200 to 500 mm. By adjusting the center-to-center distance d ₅ , the uniformity of the plasma density in the width direction of the base film 10 described later can be controlled. The center-to-center distance d ₄ and the center-to-center distance d ₅ are preferably the same. The ratio (d ₅ /d ₄ ) of the center-to-center distance d ₅ to the center-to-center distance d ₄ is, for example, 0.5 to 2.0. The center points of the extensions 71a of the four LAs 71 preferably form a square with the vertices. A high density plasma with high in-plane uniformity can be generated by such a set of LAs 71. As the LAs 71, for example, a high frequency antenna for plasma generation described in JP 2013-258153 A may be used.

In this embodiment, the plasma processing chamber C2 further includes a transport roller 53. The transport roller 53 is a main guide roller for transporting the workpiece film W in the plasma processing chamber C2. The transport roller 53 has a temperature adjustment function that can heat or cool the workpiece film W. In other words, the transport roller 53 is a transport roller with a temperature adjustment function. When the device Y is in operation, the transport roller 53 transports the base film 10 while contacting the second surface 10b of the base film 10. The LA71 is disposed opposite the transport roller 53. According to the device Y including such a plasma processing chamber C2, in the plasma processing step S2, the transport roller 53 with a temperature adjustment function that contacts the base film 10 can perform plasma processing on the base film 10 while cooling or heating the base film 10. By controlling the temperature of the base film 10, thermal deformation of the base film 10 can be suppressed, and the effect of the thermal deformation on the transport of the base film 10 can be suppressed.

The PEM device is a device for performing plasma emission monitoring (PEM) during plasma processing, and is equipped with a device body and an optical fiber for collecting light. The tip (one end) of the optical fiber is disposed in the plasma processing chamber C2, between the workpiece film W and LA71 in the direction of separation between them. The other end of the optical fiber is connected to the device body. In addition, a first line L1 with a flow control valve for introducing gas into the chamber is connected to the plasma processing chamber C2.

The connection chamber C3 is located next to the plasma processing chamber C2 in the running direction of the workpiece film W and is located before the film formation chamber C4. A predetermined number of guide rollers G for guiding the workpiece film W are provided inside the connection chamber C3. The connection chamber C3 is connected to a vacuum pump (not shown) and is configured so that the pressure inside the chamber can be adjusted. When the device Y is in operation, the pressure inside the connection chamber C3 is maintained at a predetermined pressure between the pressure inside the plasma processing chamber C2 and the pressure inside the film formation chamber C4. This ensures a pressure difference between the plasma processing chamber C2 and the film formation chamber C4.

The film-forming chamber C4 is disposed next to the connection chamber C3 in the running direction of the workpiece film W. The film-forming chamber C4 is also connected to a vacuum pump (not shown) and is configured so that the interior of the chamber can be adjusted to a predetermined vacuum level. In the film-forming chamber C4, the film-forming process S3 is carried out as described below.

In this embodiment, the film-forming chamber C4 is a sputtering film-forming chamber. The film-forming chamber C4 includes a film-forming roller 54 and a plurality of sputtering chambers 60 (sputtering chambers 60a to 60e) (a case where the number of sputtering chambers 60 is 5 is illustrated as an example). The film-forming roller 54 is a main guide roller for transporting the workpiece film W in the film-forming chamber C4. The film-forming roller 54 has a temperature adjustment function that can heat or cool the workpiece film W. The sputtering chamber 60 is a space partitioned in the film-forming chamber C4. The plurality of sputtering chambers 60 are arranged along the circumferential direction of the film-forming roller 54. Each sputtering chamber 60 opens toward the film-forming roller 54. A cathode 61 is provided in the sputtering chamber 60. A target (not shown) is arranged on the cathode 61 as a film-forming material supply material. The target is arranged on the target so as to face the film-forming roller 54. Each sputtering chamber 60 is provided with a power supply (not shown) for applying a voltage to the target to generate a glow discharge. Examples of power supplies include DC power supplies, AC power supplies, MF power supplies, RF power supplies, and MF-AC power supplies. MF-AC power supplies refer to AC power supplies with a frequency band of several kHz to several MHz. Each sputtering chamber 60 is connected to a required number of second lines (not shown) equipped with flow rate control valves for introducing gas into the chamber. In addition, a predetermined number of guide rollers G for guiding the workpiece film W are provided in the deposition chamber C4.

The connection chambers C5 and C6 are arranged in this order between the film-forming chamber C4 and the winding chamber R2 in the running direction of the workpiece film W. A predetermined number of guide rollers G for guiding the workpiece film W are provided in the connection chamber C5. A predetermined number of guide rollers G for guiding the workpiece film W are provided in the connection chamber C6. The connection chamber C5 is connected to a vacuum pump (not shown) and is configured to be able to adjust the pressure inside the chamber. The connection chamber C6 is connected to a vacuum pump (not shown) and is configured to be able to adjust the pressure inside the chamber. When the device Y is in operation, the pressure inside the connection chambers C5 and C6 is maintained at a predetermined pressure between the pressure inside the film-forming chamber C4 and the pressure inside the winding chamber R2. This ensures a pressure difference between the film-forming chamber C4 and the winding chamber R2.

The above-described apparatus Y sequentially performs the plasma treatment process S2 and the film formation process S3. Specifically, the process is as follows.

The work film W is unwound from the unwinding chamber R1. After being unwound from the unwinding chamber R1, the work film W passes through the connection chamber C1, the plasma processing chamber C2, the connection chamber C3, the film forming chamber C4, the connection chamber C5, and the connection chamber C6 in sequence, and is wound up in the winding chamber R2. The running speed of the work film W is preferably 0.5 m/min or more, more preferably 0.7 m/min or more, even more preferably 0.9 m/min or more, and also preferably 10 m/min or less, more preferably 8 m/min or less, and even more preferably 5 m/min or less. When the running speed of the work film W is equal to or greater than the lower limit, the manufacturing efficiency of the laminated film X can be ensured. When the running speed of the work film W is equal to or less than the upper limit, the quality variation of the laminated film X can be suppressed. In addition, the series of lines from the unwinding chamber R1 to the winding chamber R2 is not exposed to the atmosphere along the way, and the process is carried out in the line under a reduced pressure atmosphere. The reduced pressure atmosphere is preferably a vacuum. Under vacuum preferably means under reduced pressure of 7 Pa or less.

In the plasma treatment chamber C2, the plasma treatment process S2 is carried out. In the plasma treatment process S2, the first surface 10a of the base film 10 is plasma treated in a reduced pressure atmosphere in the plasma treatment chamber C2 (chamber). The plasma treatment may be carried out while detecting the plasma emission intensity. The plasma treatment is a treatment using inductively coupled plasma of an argon-containing gas, which is generated by applying high-frequency power to the LA71. Specifically, it is as follows.

During plasma processing, argon is supplied into the plasma processing chamber C2 through the first line L1. An inert gas other than argon may be supplied into the plasma processing chamber C2. Examples of the inert gas include krypton and xenon. The gas in the plasma processing chamber C2 may contain a gas other than the inert gas. Examples of the other gas include oxygen, nitrogen, hydrogen, and water vapor. The concentration of argon (Ar concentration) in the gas (argon-containing gas) in the plasma processing chamber C2 is preferably 50% by volume or more, more preferably 65% by volume or more, even more preferably 80% by volume or more, even more preferably 90% by volume or more, even more preferably 95% by volume or more, and particularly preferably 100% by volume. When the Ar concentration is equal to or more than the lower limit, a high-density argon plasma can be generated.

The pressure (first pressure) in the plasma processing chamber C2 during plasma processing is preferably 0.1 Pa or more, more preferably 0.2 Pa or more, even more preferably 0.3 Pa or more, and is preferably 7 Pa or less, more preferably 5 Pa or less, even more preferably 3 Pa or less. When the first pressure is equal to or greater than the lower limit, a plasma environment of sufficient density for surface modification processing of the first surface 10a of the substrate film 10 can be formed in the plasma processing chamber C2. When the first pressure is equal to or less than the upper limit, thermal damage to the first surface 10a caused by excessively high density plasma can be suppressed, and thermal deformation of the substrate film 10 can be suppressed. The first pressure can be adjusted by the amount of argon gas supplied into the plasma processing chamber C2.

The frequency of the high frequency power applied to the LA71 during plasma treatment is preferably 1 MHz or more, more preferably 5 MHz or more, and even more preferably 10 MHz or more, and is also preferably 100 MHz or less, more preferably 80 MHz or less, and even more preferably 60 MHz or less. When the frequency is equal to or greater than the lower limit, the plasma current density can be increased while stabilizing the plasma discharge. When the frequency is equal to or less than the upper limit, the antenna potential can be suppressed, and therefore damage to the substrate film 10 caused by the plasma can be suppressed. The high frequency power is also preferably 0.1 kW or more, more preferably 0.3 kW or more, and even more preferably 1.0 kW or more, and is also preferably 10 kW or less, more preferably 8 kW or less, and even more preferably 6 kW or less. When the high frequency power is equal to or greater than the lower limit, a high density plasma environment can be formed in the plasma treatment chamber C2 in the plasma treatment using inductively coupled plasma. When the high frequency power is equal to or less than the upper limit, excessive damage to the substrate caused by the plasma can be suppressed.

In the plasma treatment step S2, the plasma emission intensity during the plasma treatment may be monitored by the PEM device. Then, for example, based on the monitoring results, the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in the plasma emission is controlled to be within 811 nm to 812 nm. Also, the ratio (I ₂ /I ₁ ) of the emission peak intensity I ₂ in the wavelength range of 603 nm to 604 nm to the emission peak intensity I ₁ in the wavelength range of 706 nm to 707 nm is controlled to be 0.50 or less, preferably 0.45 or less, more preferably 0.40 or less, and even more preferably 0.35 or less. The maximum emission peak in the wavelength range of 300 nm to 900 nm in the plasma emission is an emission peak attributable to the transition of argon radicals from the ground state of 11.55 eV to the excited state of 13.08 eV. The emission peak within the wavelength range of 706 nm to 707 nm is attributed to the transition of argon radicals from the ground state of 11.55 eV to the excited state of 13.30 eV. The emission peak within the wavelength range of 603 nm to 604 nm is attributed to the transition of argon radicals from the ground state of 13.08 eV to the excited state of 15.13 eV. The wavelength of the maximum emission peak intensity Imax is within the range of 811 nm to 812 nm, and the ratio (I ₂ /I ₁ ) is 0.50 or less, which indicates that the kinetic energy of argon particles in the plasma is suppressed. Specifically, this is as shown in the examples and comparative examples described below. When the ratio (I ₂ /I ₁ ) is equal to or less than the upper limit, the excessive increase in the kinetic energy of argon particles in the plasma can be controlled, and damage to the surface of the plasma treatment target can be suppressed. The ratio ( _I2 / _I1 ) is preferably 0.01 or more, more preferably 0.10 or more, and even more preferably 0.20 or more. When the ratio ( _I2 / _I1 ) is equal to or more than the lower limit, the argon particles are kept in a moderately vigorous motion, and the activation of the surface of the plasma processing target can be promoted. Methods for controlling the plasma emission intensity include, for example, adjusting the amount of argon gas introduced into the plasma processing chamber C2, adjusting the frequency of the high-frequency power in the high-frequency power supply, and adjusting the magnitude of the applied power.

In the plasma treatment step S2, the plasma current density at the intermediate position between the LA71 and the base film 10 is preferably 1.0 mA/cm3 or ^more , more preferably 2.0 mA/cm3 or ^more , even more preferably 3.0 mA/cm3 or ^more , and also preferably 10 mA/cm3 or ^less , more preferably 8 mA/cm3 ^or less, and even more preferably 4 mA/ ^cm3 or less. When the plasma current density is equal to or greater than the lower limit, sufficient plasma argon particles can be secured in the plasma treatment chamber C2 in the plasma treatment, and the first surface 10a of the base film 10 can be appropriately modified. When the plasma current density is equal to or less than the upper limit, damage to the first surface 10a caused by excessively high density plasma argon particles can be suppressed in the plasma treatment. Examples of methods for adjusting the plasma current density include adjusting the amount of argon gas introduced into the plasma treatment chamber C2, adjusting the frequency of the high frequency power in the high frequency power source, and adjusting the magnitude of the applied power.

In the film formation step S3, following the plasma treatment step S2, an inorganic layer 20 is formed on the first surface 10a of the substrate film 10 in a reduced pressure atmosphere. The reduced pressure atmosphere is preferably a vacuum. Examples of the inorganic layer 20 include a conductive layer and an anti-reflective layer. The laminate film X having a conductive layer as the inorganic layer 20 is a transparent conductive film. The laminate film X having an anti-reflective layer as the inorganic layer 20 is an anti-reflective film. The inorganic layer 20 may be another type of layer.

Examples of materials for the conductive layer include metals and metal oxides. Examples of metals include copper, silver, gold, nickel, chromium, and alloys thereof. Examples of metal oxides include indium-containing conductive oxides and antimony-containing conductive oxides. Examples of indium-containing conductive oxides include indium tin composite oxide (ITO), indium zinc composite oxide (IZO), indium gallium composite oxide (IGO), and indium gallium zinc composite oxide (IGZO). Examples of antimony-containing conductive oxides include antimony tin composite oxide (ATO).

When forming a conductive layer as the inorganic layer 20, for example, the inorganic layer 20 (conductive layer) is formed by a sputtering method in at least one sputtering chamber 60 in the film formation chamber C4. This produces the laminated film X.

In the sputtering method, a sputtering gas (inert gas) is introduced into the deposition chamber C4, while a negative voltage is applied to a target placed on the cathode 61 in the sputtering chamber 60. This generates a glow discharge to ionize the gas atoms, and the gas ions collide with the target surface at high speed, ejecting the target material from the target surface, and the ejected target material is deposited on the substrate film 10. Examples of sputtering gases include argon, krypton, and xenon. The sputtering gas is introduced into the deposition chamber C4 via one of the second lines. The target is, for example, made of a material that forms the inorganic layer 20.

When the material of the inorganic layer 20 is a metal oxide, the sputtering method may be a reactive sputtering method. In the reactive sputtering method, oxygen (a reactive gas) is introduced into the deposition chamber C4 in addition to the sputtering gas. The oxygen is introduced into the deposition chamber C4 via another second line. In the reactive sputtering method, the target is, for example, a metal in the metal oxide that forms the inorganic layer 20.

In the sputtering method, the pressure (second pressure) in the film-forming chamber C4 is, for example, 0.1 to 5.0 Pa depending on the type of inorganic layer 20 to be formed. The film-forming temperature (the temperature of the substrate film 10 adjusted by the film-forming roller 54) is, for example, -10°C to 150°C depending on the type of inorganic layer 20. The same applies to the sputtering method described below when forming an inorganic layer 20 as an anti-reflection layer.

The thickness of the inorganic layer 20 as a conductive layer is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more, from the viewpoint of reducing the resistance of the inorganic layer 20. The thickness of the inorganic layer 20 as a conductive layer is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less, from the viewpoint of reducing the thickness of the laminated film X.

The antireflection layer includes, for example, a plurality of transparent inorganic oxide films laminated in the thickness direction H. The inorganic layer 20 as the antireflection layer includes, for example, a first high refractive index layer, a first low refractive index layer, a second high refractive index layer, and a second low refractive index layer as transparent inorganic oxide films, in this order from the substrate film 10 side. Each high refractive index layer is made of a high refractive index material having a refractive index of preferably 1.9 or more at a wavelength of 550 nm. Examples of high refractive index materials include niobium oxide (Nb ₂ O ₅ ), titanium oxide, zirconium oxide, tin-doped indium oxide (ITO), and antimony-doped tin oxide (ATO), with niobium oxide being preferred. The thickness of each high refractive index layer is, for example, 3 to 50 nm. Each low refractive index layer is made of a low refractive index material having a refractive index of preferably 1.6 or less at a wavelength of 550 nm. Examples of low refractive index materials include silicon dioxide (SiO ₂ ) and magnesium fluoride, with silicon dioxide being preferred. The thickness of each low refractive index layer is, for example, 8 to 50 nm. When forming such an anti-reflection layer as the inorganic layer 20, for example, the inorganic layer 20 (anti-reflection layer) is formed by a sputtering method in a plurality of sputtering chambers 60 in the film formation chamber C4. For example, the method is as follows.

First, a first high refractive index layer is formed on the substrate film 10 by a sputtering method in the sputtering chamber 60a. When forming a Nb ₂ O ₅ layer as the first high refractive index layer, a Nb target is used as a target disposed on the cathode 61 in the sputtering chamber 60a. Then, reactive sputtering is performed while introducing argon and oxygen into the film formation chamber C4 (reactive sputtering is similarly performed in the following sputtering methods in the sputtering chambers 60b to 60d).

Next, a first low refractive index layer is formed on the first high refractive index layer by a sputtering method in the sputtering chamber 60b. When a _SiO2 layer is formed as the first low refractive index layer, a Si target is used as a target placed on the cathode 61 in the sputtering chamber 60b.

Next, a second high refractive index layer is formed on the first low refractive index layer by sputtering in the sputtering chamber _60c . When forming a _Nb2O5 layer as the second high refractive index layer, a Nb target is used as a target disposed on the cathode 61 in the sputtering chamber 60c.

Next, a second low refractive index layer is formed on the second high refractive index layer by a sputtering method in the sputtering chamber 60d. When a _SiO2 layer is formed as the second low refractive index layer, a Si target is used as a target placed on the cathode 61 in the sputtering chamber 60d.

In device Y, after the plasma treatment process S2 and the film formation process S3, the laminated film X serving as the work film W passes through the connection chambers C5 and C6 and enters the winding chamber R2, where it is wound up by the winding roller 52.

In the manufacturing method of the laminated film X, as described above, in the plasma treatment step S2 under a reduced pressure atmosphere on the first surface 10a of the base film 10, a treatment is performed using inductively coupled plasma of argon-containing gas generated by applying high-frequency power to the LA71 (low inductance antenna). This type of plasma treatment can achieve a higher plasma current density than the above-mentioned capacitively coupled plasma treatment (for example, a plasma density about 100 times higher). The higher the plasma current density, the more dirt and moisture can be removed from the first surface 10a. The removal of dirt and moisture helps to increase the adhesion of the inorganic layer 20 formed on the first surface 10a in the film formation step S3 to the first surface 10a (base film 10). The removal of dirt and moisture also helps to ensure the original optical properties of the base film 10.

In the plasma treatment step S2, as described above, the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in the plasma emission is set to be within 811 nm to 812 nm, and the ratio (I2/ _I1 ) of the emission peak intensity _I2 within a wavelength range of 603 nm to 604 nm to the emission peak intensity _I1 within a wavelength range of 706 nm to ₇₀₇ nm is set to be 0.50 or less. By adjusting the plasma emission intensity in this manner in the plasma treatment step S2, the kinetic energy of argon particles in the plasma can be suppressed. This makes it possible to suppress deterioration of the surface of the base film 10 exposed to the plasma. This makes it possible to suppress changes in the optical properties of the base film 10.

In addition, in the film-forming step S3 after the plasma treatment step S2, as described above, the inorganic layer 20 is formed on the first surface 10a of the substrate film 10 in a reduced pressure atmosphere following the plasma treatment step S2. That is, the substrate film 10 is not placed under atmospheric pressure between the plasma treatment step S2 and the film-forming step S3. Such a film-forming step S3 can suppress or prevent foreign matter from being mixed between the substrate film 10 and the inorganic layer 20. This is useful for producing a laminate film X with good optical properties.

Therefore, the above-mentioned laminated film manufacturing method can produce a laminated film X that has an inorganic layer 20 on a base film 10 and has good optical properties.

The inorganic layer 20 of the laminated film X may include a conductive layer on the base film 10 and an anti-reflection layer on the conductive layer. The anti-reflection layer may include the first high refractive index layer, the first low refractive index layer, the second high refractive index layer, and the second low refractive index layer, in this order from the conductive layer side. When forming such an inorganic layer 20, in the film forming chamber C4, a conductive layer is formed by sputtering in the sputtering chamber 60a, a first high refractive index layer is formed by sputtering in the sputtering chamber 60b, a first low refractive index layer is formed by sputtering in the sputtering chamber 60c, a second high refractive index layer is formed by sputtering in the sputtering chamber 60d, and a second low refractive index layer is formed by sputtering in the sputtering chamber 60e. In this way, a transparent conductive film with an anti-reflection layer may be manufactured.

The inorganic layer 20 of the laminated film X may include an adhesive layer on the substrate film 10 and the above-mentioned anti-reflection layer on the adhesive layer. The adhesive layer is a layer for ensuring the adhesion of the anti-reflection layer to the substrate film 10 (mainly made of an organic material). Examples of materials for such adhesive layers include oxides of metals such as silicon, nickel, chromium, aluminum, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, and palladium. From the viewpoint of achieving both adhesion to both the substrate film 10 and the anti-reflection layer and transparency of the adhesive layer, the material for the adhesive layer is preferably indium tin oxide (ITO) or silicon oxide (SiOx). The silicon oxide is preferably SiOx with a smaller amount of oxygen than the stoichiometric composition, and more preferably SiOx with x being 1.2 or more and 1.9 or less.

The anti-reflection layer on the adhesion layer may include the above-mentioned first high refractive index layer, first low refractive index layer, second high refractive index layer, and second low refractive index layer, in this order from the adhesion layer side. When forming such an inorganic layer 20, in the film formation chamber C4, the adhesion layer is formed by sputtering in the sputtering chamber 60a, the first high refractive index layer is formed by sputtering in the sputtering chamber 60b, the first low refractive index layer is formed by sputtering in the sputtering chamber 60c, the second high refractive index layer is formed by sputtering in the sputtering chamber 60d, and the second low refractive index layer is formed by sputtering in the sputtering chamber 60e.

As shown in FIG. 7, the above-mentioned device Y may be provided with a plasma processing chamber C2' instead of the plasma processing chamber C2 (FIG. 4). The plasma processing chamber C2' differs from the plasma processing chamber C2 in that it does not include the transport rollers 53. In other words, the device Y does not need to include the transport rollers 53.

In the above embodiment, in the film formation process S3, the inorganic layer 20 is formed by a sputtering method. In the film formation process S3, the inorganic layer 20 may be formed by a vapor deposition method instead of the sputtering method. In that case, the apparatus Y has a vapor deposition chamber as the film formation chamber C4 instead of the sputtering film formation chamber. In the film formation process S3, the inorganic layer 20 may be formed by a chemical vapor deposition method (CVD) instead of the sputtering method. In that case, the apparatus Y has a CVD chamber as the film formation chamber C4 instead of the sputtering film formation chamber. The method of forming the inorganic layer 20 can be selected depending on the material and thickness of the inorganic layer 20, etc.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples. In addition, the specific numerical values of the compounding amounts (contents), physical property values, parameters, etc. described below can be replaced with the upper limit (a numerical value defined as "equal to or less than") or lower limit (a numerical value defined as "equal to or more than") of the corresponding compounding amounts (contents), physical property values, parameters, etc. described in the above-mentioned "Form for carrying out the invention."

Example 1
The sample film of Example 1 was produced by carrying out the following steps in sequence.

First, a hard coat layer was formed on one side of a triacetyl cellulose (TAC) film as a resin film to prepare a substrate film (preparation step). Specifically, first, 100 parts by mass (solid content equivalent value) of a butyl acetate solution of an ultraviolet-curable acrylic urethane resin (product name "Luxidia 17-806", solid content concentration 80% by mass, manufactured by DIC Corporation), 5 parts by mass of a photopolymerization initiator (product name "Omnirad 907", manufactured by IGM Resins), 0.03 parts by mass of a leveling agent (product name "GRANDIC PC4100", manufactured by DIC Corporation), and butyl acetate as a solvent were mixed to prepare a first resin composition with a solid content concentration of 75% by mass. Next, cyclopentanone was added as an additional solvent to the first resin composition to prepare a second resin composition with a solid content concentration of 50% by mass. Meanwhile, a long TAC film (length 100 m, width 340 mm, thickness 40 μm) was prepared. Next, the second resin composition was applied to one side of the TAC film to form a coating film. Next, the coating film was dried by heating and then cured by ultraviolet irradiation. As a result, a hard coat (HC) layer having a thickness of 5 μm was formed on the TAC film. The heating temperature was 100° C., and the heating time was 60 seconds. For ultraviolet irradiation, a high-pressure mercury lamp was used as a light source, and ultraviolet rays with a wavelength of 365 nm were irradiated onto the coating film, with an integrated irradiation amount of 300 mJ/cm ^2. In this manner, a TAC film with an HC layer was produced as a substrate film.

Next, while the base film was transported in a vacuum by a roll-to-roll method, the base film was subjected to plasma treatment (plasma treatment process). In this process, an apparatus capable of performing a roll-to-roll process on the work film was used. The apparatus includes a payout chamber, a plasma treatment chamber, a film formation chamber, and a winding chamber. The payout chamber, the plasma treatment chamber, the film formation chamber, and the winding chamber are arranged in this order and communicate with each other. The payout chamber includes a payout roller. A roll of the base film was set on the payout roller as the work film. The plasma treatment chamber includes a temperature-adjustable transport roller (transport roller 53 in FIG. 4) and four low-inductance antennas (LA71 in FIG. 5 and FIG. 6) covered with a cover block (cover block 73 in FIG. 6) as shown in FIG. 5 and FIG. 6. Each low-inductance antenna has an extension portion (extension portion 71a in FIG. 5) parallel to the base film. In the four low inductance antennas, the extension length d ₁ is 88 mm, the maximum length d ₂ (length of the extension) is 100 mm, the separation distance d ₃ is 112 mm, the center distance d ₄ is 290 mm, and the center distance d ₅ is 280 mm (FIGS. 5 and 6). Each low inductance antenna is electrically connected to a high frequency power source (RF power source, frequency 13.56 MHz) via an impedance matching device outside the plasma processing chamber. The separation distance d' between the base film traveling in the plasma processing chamber and the cover block is 100 mm. The film formation chamber is a sputtering film formation chamber, and includes a film formation roller and a cathode arranged opposite the film formation roller. The winding chamber includes a winding roller.

Specifically, in this process, the base film was transported from the unwinding chamber to the winding chamber using a roll-to-roll method, and in the plasma treatment chamber, the HC surface (first surface) of the base film was plasma treated while detecting the plasma emission intensity. The running speed of the base film (film running speed) was 1.0 m/min. The temperature of the temperature-adjustable transport roller was -8°C. The plasma emission intensity was detected by a spectrometer (product name "Qwave2", manufactured by Broadcom) via an optical fiber whose tip was placed in the plasma treatment chamber. The plasma treatment conditions were as follows:

After the apparatus was evacuated until the ultimate vacuum of the plasma treatment chamber reached 1.0×10 ⁻⁴ Pa, argon gas was introduced as an inert gas into the plasma treatment chamber, and the atmospheric pressure in the plasma treatment chamber was set to 0.5 Pa. A high-frequency power of 2.0 kW was applied to the four low-inductance antennas by a high-frequency power source, and an inductively coupled plasma of argon-containing gas was formed around the antennas (the HC layer surface of the base film was treated with this plasma). As a result, the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in the plasma emission was set to 811 nm, and the ratio (I _{2 /I 1} ) of the emission peak intensity I ₂ in the wavelength range of 603 nm to 604 nm to the emission peak intensity I ₁ in the wavelength range of 706 nm to 707 _nm in the plasma emission was set to 0.32. The plasma current density at the midpoint between the low-inductance antennas and the base film was set to 1.3 mA/cm ³ . The plasma current density was measured by a Langmuir probe for plasma measurement.

As described above, the plasma treatment process was carried out on the base film. The base film obtained in this manner was used as the sample film of Example 1. The plasma treatment in Example 1 was a treatment using inductively coupled plasma (Ar-LAICP treatment) using argon-containing gas, which was generated by applying high-frequency power to a low-inductance antenna (the plasma treatment in Examples 2 and 3 was the same).

Example 2
The sample film of Example 2 was obtained in the same manner as the sample film of Example 1, except for the following: In the plasma treatment step, the applied high-frequency power was 3.5 kW, the ratio ( _I2 / _I1 ) was 0.31, and the plasma current density was 2.4 mA/ ^cm3 .

Example 3
A sample film of Example 3 was obtained in the same manner as the sample film of Example 1, except for the following: In the plasma treatment step, the applied high-frequency power was 5.0 kW, the ratio ( _I2 / _I1 ) was 0.29, and the plasma current density was 4.2 mA/ ^cm3 .

Comparative Example 1
First, in the same manner as in the preparation process of Example 1, a HC layer was formed on one side of a TAC film to prepare a base film (TCA film/HC layer).

Next, the base film was subjected to plasma treatment while being transported in a vacuum by a roll-to-roll method (plasma treatment process). In this process, an apparatus capable of performing a roll-to-roll process on the work film was used. The apparatus includes a payout chamber, a plasma treatment chamber, a film-forming chamber, and a winding chamber. The payout chamber, plasma treatment chamber, film-forming chamber, and winding chamber are arranged in this order and are connected to each other. The payout chamber includes a payout roller. A roll of the above-mentioned base film was set on the payout roller as the work film. The plasma treatment chamber includes a cathode electrode and an anode electrode (both rectangular electrodes made of SUS304) as a pair of flat electrodes for generating plasma. The pair of flat electrodes are arranged parallel to the base film passing through the plasma treatment chamber with a gap of 50 mm. The anode electrode is arranged at a position 35 mm away from the base film passing through the plasma treatment chamber and is grounded outside the plasma treatment chamber. The cathode electrode is disposed so as to face the HC layer surface of the substrate film, and is electrically connected to a high-frequency power source (RF power source, 13.56 MHz) via an impedance matcher. The length of each electrode in the film running direction is 110 mm, and the length in the width direction is 430 mm. The film formation chamber is a sputtering film formation chamber, and is equipped with a film formation roller and a cathode disposed opposite the film formation roller. The winding chamber is equipped with a winding roller.

Specifically, in this process, the base film was transported from the unwinding chamber to the winding chamber using a roll-to-roll method, while the HC surface (first surface) of the base film was subjected to plasma treatment (bombardment treatment) in the plasma treatment chamber while detecting the plasma emission intensity. The running speed of the base film (film running speed) was 1.0 m/min. The plasma emission intensity was detected by a spectrometer (product name "Qwave2", manufactured by Broadcom) via an optical fiber whose tip was placed in the plasma treatment chamber. The plasma treatment conditions were as follows:

The apparatus was evacuated until the ultimate vacuum of the plasma treatment chamber reached 1.0×10 ⁻⁴ Pa, and then argon gas was introduced as an inert gas into the plasma treatment chamber, and the atmospheric pressure in the plasma treatment chamber was set to 0.5 Pa. A capacitively coupled plasma (CCP) was generated by applying a power of 300 W between the planar electrodes by a high-frequency power source. In this plasma environment, a bombardment treatment was performed with argon ions on the surface of the HC layer of the substrate film. In this treatment, the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in the plasma emission was 750 nm. The ratio (I 2 /I ₁ ) of the emission peak intensity I 2 in the wavelength range of 603 nm to 604 nm in the plasma emission to the emission peak intensity I ₁ in the wavelength range of ₇₀₆ nm to ₇₀₇ nm in the plasma emission was 1.19.

As described above, the plasma treatment process was carried out on the substrate film. The substrate film obtained in this manner was used as the sample film of Comparative Example 1. The plasma treatment in Comparative Example 1 was an ion bombardment process, specifically a process using capacitively coupled plasma using an argon-containing gas (Ar-BB) (the plasma treatment in Comparative Example 2 was the same).

Comparative Example 2
A sample film of Comparative Example 2 was obtained in the same manner as the sample film of Comparative Example 1, except for the following: In the plasma treatment step, the applied power was 550 W, and the emission peak intensity ratio (I ₂ /I ₁ ) was 1.01.

<Surface free energy>
The surface free energy of the plasma-treated surface of each of the sample films of Examples 1 to 3 and Comparative Examples 1 and 2 was determined as follows.

First, the sample film was placed on a horizontally placed slide glass. Specifically, the sample film was placed on the slide glass so that the plasma-treated surface (HC layer surface) of the sample film was facing upward. Next, 2 μL of a specific liquid was dropped onto the plasma-treated surface of the sample film on the slide glass in an atmosphere of 23° C. and 50% relative humidity to form a droplet (droplet formation). Next, the contact angle of the droplet with respect to the sample film surface (plasma-treated surface) was measured using a contact angle meter (product name "DMs-401", manufactured by Kyowa Interface Science Co., Ltd.) (contact angle measurement). As the liquids, water (H ₂ O), methylene iodide (CH ₂ I ₂ ), and 1-bromonaphthalene were used. For each liquid, a series of operations including droplet formation and subsequent contact angle measurement were performed five times. The measurement was performed within 24 hours after the plasma treatment of the substrate film. The average of the five measurements for each liquid was taken as the contact angle with that liquid. In this manner, the contact angle θw of water, the contact angle θi of methylene iodide, and the contact angle θb of 1-bromonaphthalene were obtained for the sample film.

Next, for each sample film, the values of the contact angle of water θw, the contact angle of methylene iodide θi, and the contact angle of 1-bromonaphthalene θb were used to solve the three-dimensional simultaneous equation in the Kitazaki-Hata theory, and γ ^d , γ p , and γ ^h in the equation γ = γ ^d + γ ^p + γ ^h, which represents the surface free energy γ, were derived. The Kitazaki-Hata theory is described, for example, in Vol. 8, No. 3, pp. 131-141 (1972) of the Journal of the Japan Adhesion Association. In the ^equation , γ ^d is the dispersion component of the surface free energy, γ ^p is the polar component of the surface free energy, and γ ^h is the hydrogen bond component of the surface free energy. The value (γ) obtained by adding γ ^d , γ ^p , and γ ^h was determined as the surface free energy of the plasma-treated surface of the sample film. The values required for derivation were: dispersion component ^γd of the surface free energy of water was set to 29.1 mN/m, polar component ^γp was set to 1.3 mN/m, and hydrogen bond component ^γh was set to 42.4 mN/m. The dispersion component ^γd of the surface free energy of methylene iodide was set to 46.8 mN/m, polar component ^γp was set to 4.0 mN/m, and hydrogen bond component ^γh was set to 0.0 mN/m. The dispersion component ^γd of the surface free energy of 1-bromonaphthalene was set to 44.4 mN/m, polar component ^γp was set to 0.1 mN/m, and hydrogen bond component ^γh was set to 0.0 mN/m. The surface free energy (mN/m) of the plasma-treated surface of the sample film is shown in Table 1.

Elemental composition analysis
The respective proportions of chromium (Cr) and iron (Fe) present on the plasma-treated surface of each of the sample films of Examples 1 to 3 and Comparative Examples 1 and 2 were examined.

Specifically, first, a sample film piece (1 cm x 1 cm) was cut out from the center of the width direction of the sample film. Next, the elemental composition of the plasma-treated surface of the sample film piece was analyzed by X-ray photoelectron spectroscopy (XPS). For the analysis, an X-ray photoelectron spectrometer (product name "Quantera SXM", manufactured by ULVAC-PHI, Inc.) was used. In this analysis, a narrow scan was performed under the following conditions to analyze Cr and Fe, and the elemental ratios (atomic %) of Cr and Fe were obtained. The results are shown in Table 1. Cr and Fe were not detected in the sample films of Examples 1 to 3 (Table 1 shows that the values were below the detection limit of 0.1 atomic %).

Excitation X-ray source: Monochrome AI Kα
X-ray Setting: 100μmφ (15kV, 25W)
Photoelectron take-off angle: 45° to the sample surface
Neutralization conditions: Use of neutralization gun and Ar ion gun (neutralization mode)

Optical properties
For each sample film of Examples 1 to 3 and Comparative Examples 1 and 2, the luminous transmittance (Y value) at wavelengths of 380 nm to 780 nm and the hue b ^* of transmitted light were examined. Specifically, the transmission spectrum of the sample film was measured at wavelengths of 380 nm to 780 nm using a spectrophotometer (product name "U4100", manufactured by Hitachi, Ltd.), and the luminous transmittance and hue b ^* were calculated based on the transmission spectrum. The measurement was performed in the integrating sphere measurement mode of the spectrophotometer. In the measurement, a D65 light source was used as the light source, and the sample film was placed in the spectrophotometer so that light was incident on the HC layer side of the sample film. The luminous transmittance is the transmittance (Y value) in the CIE-XYZ color system. The hue b ^* is the hue b ^* in the L ^* a ^* b ^* color system. The Y value (%) and b ^* are shown in Table 1.

[evaluation]
The plasma treatment in the manufacturing process of each of the sample films of Comparative Examples 1 and 2 was a treatment by capacitively coupled plasma using an argon-containing gas (ion bombardment treatment) as described above, in which the wavelength of the maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in the plasma emission was 750 nm, and the ratio ( _I2 / _{I1 )} of the emission peak intensity _I2 in the wavelength range of 603 nm to 604 nm to the emission peak intensity I1 in the wavelength range of 706 nm to 707 nm was significantly greater than 0.50. In contrast, the plasma treatment in the manufacturing process of each of the sample films of Examples 1 to 3 was a treatment by inductively coupled plasma using an argon-containing gas generated by application of high-frequency power to a low-inductance antenna as described above, in which the wavelength of the intensity Imax was 811 nm to 812 nm, and the ratio ( _I2 / _I1 ) was 0.50 or less. Therefore, as shown in Table 1, the sample films of Examples 1 to 3 had higher Y values and lower b ^* values than the sample films of Comparative Examples 1 and 2. That is, the sample films of Examples 1 to 3 were cleaner and had better optical properties than the sample films of Comparative Examples 1 and 2. In addition, the surface free energy of the plasma-treated surface of each of the sample films of Examples 1 to 3 was higher than that of the sample films of Comparative Examples 1 and 2. That is, the sample films of Examples 1 to 3 were cleaner and had more active surfaces than the sample films of Comparative Examples 1 and 2. The above results of elemental composition analysis show that the sample films of Examples 1 to 3 were cleaner than the sample films of Comparative Examples 1 and 2.

X: Laminated film H: Thickness direction D: Plane direction 10: Base film 10a: First surface 10b: Second surface 11: Resin film 12: Cured resin layer 20: Inorganic layer 71: Low inductance antenna (LA)
C2 Plasma treatment chamber C4 Film formation chamber 53 Transport roller (roller with temperature control function)

Claims (7)

A preparation step of preparing a long base film having a first surface and a second surface opposite to the first surface;
a plasma treatment step of plasma treating the first surface of the base film in a reduced pressure atmosphere in a chamber;
a film-forming step of forming an inorganic layer on the first surface under a reduced pressure atmosphere following the plasma treatment step,
In the plasma treatment step,
the plasma treatment is a treatment with an inductively coupled plasma of an argon-containing gas generated by application of high frequency power to a low inductance antenna;
A method for producing a laminated film, wherein the wavelength of a maximum emission peak intensity Imax in the wavelength range of 300 nm to 900 nm in plasma emission is set to be within a range of 811 nm to 812 nm, and the ratio of an emission peak intensity _I2 within a wavelength range of 603 nm to 604 nm to an emission peak intensity _I1 within a wavelength range of 706 nm to 707 nm is set to 0.50 or less. The method for producing a laminated film according to claim 1, wherein in the plasma treatment step, the base film is conveyed in the chamber while being cooled or heated by a roller with a temperature control function that contacts the base film. The method for manufacturing a laminated film according to claim 1, wherein the low inductance antenna has a coil shape or an open loop shape. The method for producing a laminated film according to claim 1 , wherein in the plasma treatment step, a plasma current density at an intermediate position between the low inductance antenna and the base film is set to 1.0 mA/cm ³ or more and 10 mA/cm ³ or less. The method for producing a laminated film according to claim 1, wherein the inorganic layer is formed by sputtering, deposition, or chemical vapor deposition in the film formation process. The method for producing a laminated film according to any one of claims 1 to 5, wherein a conductive layer is formed as the inorganic layer in the film forming process. The method for manufacturing a laminated film according to any one of claims 1 to 5, wherein in the film formation process, an anti-reflection layer is formed as the inorganic layer, and the anti-reflection layer includes a plurality of transparent inorganic oxide films laminated in the thickness direction.

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