Light control film

Abstract

To provide a light control film suitable for achieving a good heat shielding property against sunlight.SOLUTION: A reflective film X is provided, comprising a base material film 10, an electrode layer 20, a light control layer 30, and an electrode layer 40 arranged in the described order in a thickness direction H. The electrode layer 20 is an indium-containing conductive oxide layer. The electrode layer 20 has a resistivity of 2.5×10-4 Ωcm or less. The electrode layer 20 is a crystalline layer with an average crystal size of 300 nm or less in a plane direction and includes a region containing multiple crystal grains in the thickness direction H.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a dimming film.

Background Art

[0002] There is known a dimming film that is bonded to window glass of buildings, vehicles, and the like. The dimming film includes a dimming portion and a transparent base film that supports the dimming portion. The dimming portion includes, for example, a transparent conductive layer, a dimming layer, and a transparent conductive layer in this order in the thickness direction. The dimming layer is sandwiched between two transparent conductive layers. The dimming layer is formed of an electrochromic (EC) material. The EC material is a material that can be reversibly changed between a colored non-transparent state and a colorless transparent state, for example, by electrochemical oxidation-reduction. Each transparent conductive layer is an electrode layer. By turning on and off the voltage between the electrodes (transparent conductive layers), the dimming layer can be switched, for example, between a non-transparent state (light-shielding state) and a transparent state (non-light-shielding state). In a window glass to which such a dimming film is bonded, the transmittance of light such as visible light with respect to the window glass with the dimming film is switched (light transmittance switching control) by turning on and off the voltage between the electrodes. Technologies related to such dimming films are described in, for example, Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] From the viewpoints of improving comfort inside buildings and vehicles and reducing cooling loads, etc., the dimming film is required to have heat insulation properties against sunlight.

[0005] On the one hand, the inventors of the present invention have obtained the following findings regarding the dimming film. The electrode (transparent conductive layer) contains free electrons having significant reflectivity with respect to heat rays (electromagnetic waves such as near-infrared rays that transmit heat by radiation) in sunlight as carriers. In the dimming film, such an electrode is provided entirely on the dimming layer. That is, the occupation area ratio of the electrode in the plane direction in the dimming film is large. In such a dimming film, by adjusting the number of carriers in the electrode, the heat insulation property of the film with respect to sunlight can be efficiently controlled. The present invention is based on such findings.

[0006] The present invention provides a dimming film suitable for realizing good heat insulation property with respect to sunlight.

Means for Solving the Problems

[0007] The present invention [1] is a dimming film including a base film, a first electrode layer, a dimming layer, and a second electrode layer in this order in the thickness direction, wherein the first electrode layer is an indium-containing conductive oxide layer, and the first electrode layer has a specific resistance of 2.5×10 -4 Ω·cm or less, and the first electrode layer is a crystalline layer having an average crystal grain size of 300 nm or less in the plane direction and having a region containing a plurality of crystal grains in the thickness direction.

[0008] The present invention [2] includes the dimming film according to the above [1], wherein the indium-containing conductive oxide is an indium tin composite oxide having an indium oxide ratio of 11% by mass or more.

[0009] The present invention [3] includes the dimming film according to the above [1] or [2], wherein the second electrode layer is an indium-containing conductive oxide layer.

[0010] The present invention [4] includes the dimming film according to the above [3], wherein the indium-containing conductive oxide in the second electrode layer is an indium tin composite oxide having an indium oxide ratio of 11% by mass or more.

[0011] The present invention [5] is such that the second electrode layer has a specific resistance of 2.5×10 -4 Ω·cm or less and includes the dimming film according to any one of [1] to [4] above.

[0012] The present invention [6] is such that the second electrode layer is a crystalline layer having an average crystal grain size in the plane direction of 300 nm or less and includes the dimming film according to any one of [1] to [5] above.

[0013] The present invention [7] is such that the second electrode layer has a region including a plurality of crystal grains in the thickness direction and includes the dimming film according to [6] above.

[0014] The present invention [8] is such that the base film has a near-infrared absorption layer and / or a near-infrared reflection layer and includes the dimming film according to any one of [1] to [7] above.

[0015] The present invention [9] is such that the average transmittance at a wavelength of 800 nm to 1300 nm is 50% or less and includes the dimming film according to any one of [1] to [8] above.

Advantages of the Invention

[0016] As described above, the dimming film of the present invention includes a base film, a first electrode layer, a dimming layer, and a second electrode layer in this order in the thickness direction. The first electrode layer is an indium-containing conductive oxide layer having a specific resistance of 2.5×10 -4 Ω·cm or less, is a crystalline layer having an average crystal grain size in the plane direction of 300 nm or less, and has a region including a plurality of crystal grains in the thickness direction. Such a dimming film is suitable for ensuring the number of free electrons (carrier number) per unit area in a plan view of the first electrode layer. The higher the number of free electrons per unit area in the first electrode layer, the higher the reflectivity of the first electrode layer to the heat rays in sunlight. The higher the reflectivity of the first electrode layer to the heat rays, the higher the shielding property (heat insulation property) of the dimming film including such a first electrode layer to the heat rays. Therefore, the dimming film of the present invention is suitable for realizing good heat insulation property against sunlight.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0018] The dimming film X as an embodiment of the present invention includes a base film 10 (first base film), an electrode layer 20 (first electrode layer), a dimming layer 30, an electrode layer 40 (second electrode layer), and a base film 50 (second base film) in this order in the thickness direction H. The base film 10 has a first surface 10a and a second surface 10b opposite to the first surface 10a. The electrode layer 20 is disposed on the first surface 10a. The electrode layer 20 and the first surface 10a are in contact with each other. The dimming layer 30 is disposed on the electrode layer 20. The dimming layer 30 and the electrode layer 20 are in contact with each other. The electrode layer 40 is disposed on the dimming layer 30. The electrode layer 40 and the dimming layer 30 are in contact with each other. The base film 50 is disposed on the electrode layer 40. The base film 50 has a first surface 50a on the electrode layer 40 side and a second surface 50b opposite to the first surface 50a. The electrode layer 40 and the first surface 50a are in contact with each other. Further, the dimming film X has a sheet shape extending in a direction (plane direction) orthogonal to the thickness direction H.

[0019] In the dimming film X, the base film 10 and the electrode layer 20 form an electrode-attached base film Y1.

[0020] 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. The cured resin layer 12 is in contact with the resin film 11. The cured resin layer 12 forms the first surface 10a of the base film 10.

[0021] The resin film 11 is a base material for ensuring the strength of the light control film X. Further, the resin film 11 is a flexible transparent resin film. Examples of the material of the resin film 11 include polyester resin, polyolefin resin, acrylic resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose 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. Examples of the acrylic resin include polymethacrylate. From the viewpoints of transparency and strength, the material of the resin film 11 is preferably a polyester resin, and more preferably PET.

[0022] The surface of the resin film 11 on the side of the cured resin layer 12 may be surface-modified. Examples of the surface modification treatment include corona treatment, plasma treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment (the same applies to the surface modification treatment for the resin film 51 described later).

[0023] From the viewpoint of ensuring the strength of the light control film X, the thickness of the resin film 11 is preferably 10 μm or more, more preferably 20 μm or more, and still more preferably 30 μm or more. From the viewpoint of ensuring the handleability of the resin film 11 in the roll-to-roll method, the thickness of the resin film 11 is preferably 300 μm or less, more preferably 200 μm or less, and still more preferably 150 μm or less. From the viewpoint of achieving both the strength and handleability of the light control film X, the thickness of the resin film 11 is preferably 10 to 300 μm, more preferably 20 to 200 μm, and still more preferably 30 to 150 μm.

[0024] From the viewpoint of ensuring the transparency required for the light control film X in the transparent state of the light control film, the visible light transmittance of the resin film 11 is preferably 70% or more, more preferably 80% or more, and still more preferably 85% or more. The visible light transmittance of the resin film 11 is, for example, 100% or less. The visible light transmittance is defined as the transmittance in the wavelength range of 380 nm to 780 nm.

[0025] In the present embodiment, the cured resin layer 12 is an optical adjustment layer (refractive index adjustment layer) for improving the optical properties of the light control film X. The cured resin layer 12 may have a function of blocking moisture and organic gases generated from the resin film 11 in the transparent conductive layer forming step (FIG. 4B) described later. In the present embodiment, the cured resin layer 12 is a cured product of a curable first resin composition. The first resin composition contains a resin. Examples of the resin include melamine resin, alkyd resin, organic silane condensate, polyester resin, acrylic urethane resin, acrylic resin (excluding acrylic urethane resin), urethane resin (excluding acrylic urethane resin), amide resin, silicone resin, and epoxy resin. These resins may be used alone or in combination of two or more. The resin in the first resin composition is preferably at least one selected from the group consisting of melamine resin, alkyd resin, and organic silane condensate from the viewpoint of ensuring the adhesion of the electrode layer 20 to the base film 10. The first resin composition may be an ultraviolet curable resin composition or a thermosetting resin composition.

[0026] From the perspective of improving the light transmission characteristics of the dimming film X, the thickness of the cured resin layer 12 is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, and even more preferably 30 nm or more. From the perspective of thinning the dimming film X, the thickness of the cured resin layer 12 is preferably 1000 nm or less, more preferably 100 nm or less, still more preferably 50 nm or less, and even more preferably 40 nm or less. From the perspective of achieving both good light transmission characteristics and thinning of the dimming film X, the thickness of the cured resin layer 12 is preferably 5 to 1000 nm, more preferably 10 to 100 nm, still more preferably 20 to 50 nm, and even more preferably 30 to 40 nm.

[0027] The base film 10 may have another cured resin layer on the side opposite to the cured resin layer 12 with respect to the resin film 11. Examples of the other cured resin layer include a hard coat layer and an anti-blocking layer. In FIG. 1, the other cured resin layer in the base film 10 is indicated by a virtual line as the cured resin layer 13.

[0028] The other cured resin layer is, for example, a cured product of a curable second resin composition. The second resin composition contains a resin. Examples of the 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 resins may be used alone or in combination of two or more. The second resin composition may be an ultraviolet curable resin composition or a thermosetting resin composition.

[0029] The second resin composition may contain particles. Examples of such particles include inorganic oxide particles and organic particles. Examples of the material of the inorganic oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of the material of 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 the group consisting of silica particles and zirconia particles.

[0030] From the viewpoint of ensuring the function of the cured resin layer, the thickness of the other cured resin layer is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 2 μm or more. From the viewpoint of thinning the dimming film X, the thickness of this cured resin layer is preferably 10 μm or less, more preferably 5 μm or less, still more preferably 3 μm or less. From the viewpoint of achieving both the function assurance of this cured resin layer and the thinning of the dimming film X, the thickness of this cured resin layer is preferably 0.5 to 10 μm, more preferably 1 to 5 μm, still more preferably 2 to 3 μm.

[0031] From the viewpoint of ensuring the handleability of the dimming film X, the thickness of the base film 10 is preferably 10 μm or more, more preferably 30 μm or more, still more preferably 50 μm or more, and even more preferably 60 μm or more. From the viewpoint of thinning the dimming film X, the thickness of the base film 10 is preferably 500 μm or less, more preferably 300 μm or less, still more preferably 200 μm or less, and even more preferably 150 μm or less. From the viewpoint of achieving both the handleability and the thinning of the dimming film X, the thickness of the base film 10 is preferably 10 to 500 μm, more preferably 30 to 300 μm, still more preferably 50 to 200 μm, and even more preferably 60 to 150 μm.

[0032] The visible light transmittance of the base film 10 is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, from the viewpoint of ensuring the transparency required for the light control film X in the transparent state of the light control film. The visible light transmittance of the base film 10 is, for example, 100% or less.

[0033] The base film 10 preferably has a near-infrared absorption layer and / or a near-infrared reflection layer (each layer is not shown). The near-infrared absorption layer means a layer that exhibits significant absorption ability for near-infrared rays (wavelength 700 nm to 2500 nm). The near-infrared reflection layer means a layer that exhibits significant reflection ability for near-infrared rays (wavelength 700 nm to 2500 nm).

[0034] The near-infrared absorption layer may be disposed between the resin film 11 and the cured resin layer 12, or may be disposed on the side opposite to the cured resin layer 12 with respect to the resin film 11. The resin film 11 may be the near-infrared absorption layer or may have a multilayer structure including the near-infrared absorption layer. The near-infrared absorption layer includes, for example, a near-infrared absorber and a binder resin. Examples of the near-infrared absorber include inorganic near-infrared absorbers and organic near-infrared absorbers. Examples of the inorganic near-infrared absorber include CFM composite oxide particles and tungsten oxide particles. The CFM composite oxide is a composite oxide of copper, iron, and manganese. Examples of the material of the binder resin include the materials described above with respect to the resin film 11.

[0035] The near-infrared reflection layer may be disposed between the resin film 11 and the cured resin layer 12, or may be disposed on the side opposite to the cured resin layer 12 with respect to the resin film 11. The resin film 11 may be the near-infrared reflection layer, or may have a multilayer structure including the near-infrared reflection layer. The near-infrared reflection layer has, for example, a multilayer structure including a plurality of resin thin layers having different optical properties, and preferably has a multilayer structure in which a first resin thin layer and a second resin thin layer having different optical properties are alternately arranged in the thickness direction H. Examples of the optical properties include the in-plane average refractive index. The difference in the in-plane average refractive index between the first resin thin layer and the second resin thin layer is preferably 0.01 or more, more preferably 0.03 or more, and preferably 0.15 or less, more preferably 0.12 or less. The number of stacked resin thin layers forming the multilayer structure is, for example, 20 or more and, for example, 700 or less. Examples of the material of the resin thin layer include the materials described above with respect to the resin film 11.

[0036] The electrode layer 20 is a layer having both light transmissivity and conductivity. Such an electrode layer 20 is formed of a transparent conductive material. That is, the electrode layer 20 is a transparent conductive layer.

[0037] The electrode layer 20 is formed of an indium-containing conductive oxide as a transparent conductive material. That is, the electrode layer 20 is an indium-containing conductive oxide layer. Examples of the indium-containing conductive oxide include indium tin composite oxide (ITO), indium zinc composite oxide (IZO), indium gallium composite oxide (IGO), and indium gallium zinc composite oxide (IGZO). From the viewpoint of realizing high transparency and good electrical conductivity, the indium-containing conductive oxide is preferably ITO. This ITO may contain a metal or a semimetal other than In and Sn in an amount less than the respective contents of In and Sn.

[0038] The ratio of the content of tin oxide to the total content of indium oxide (In2O3) and tin oxide (SnO2) in ITO (tin oxide ratio) preferably is 11% by mass or more, more preferably 12% by mass or more, still more preferably 12.5% by mass or more, from the viewpoint of moderately suppressing the growth of crystal grains in the transparent conductive layer in the crystallization process (Fig. 4C) described later and ensuring the number of carriers in the electrode layer 20. The tin oxide ratio preferably is 18% by mass or less, more preferably 16% by mass or less, still more preferably 14% by mass or less, from the viewpoint of reducing the resistance of the electrode layer 20. The tin oxide ratio preferably is 11 to 18% by mass, more preferably 12 to 16% by mass, still more preferably 12.5 to 14% by mass, from the viewpoint of achieving both the above-mentioned ensuring of the number of carriers and the above-mentioned reduction of resistance.

[0039] The tin oxide ratio in ITO can be identified, for example, as follows. First, the abundance ratio of indium atoms (In) and tin atoms (Sn) in ITO as the measurement object is determined by X-ray Photoelectron Spectroscopy. From the respective abundance ratios of In and Sn in ITO, the ratio of the number of Sn atoms to the number of In atoms in ITO is determined. Thereby, the tin oxide ratio in ITO is obtained. Also, the tin oxide ratio in ITO can be specified from the tin oxide (SnO2) content ratio of the ITO target used during sputter film formation.

[0040] The electrode layer 20 is a crystalline layer. The fact that the electrode layer 20 is a crystalline layer is preferable from the viewpoint of reducing the resistance of the electrode layer 20, and is also preferable for realizing good infrared reflection characteristics in the electrode layer 20 and the dimming film X.

[0041] That the electrode layer (electrode layers 20 and 40 in the dimming film X) formed of a conductive oxide is a crystalline layer (crystalline film) can be determined, for example, by the following method. First, immerse the electrode layer in hydrochloric acid with a concentration of 5% by mass at 20°C for 15 minutes. Next, wash the electrode layer with water and then dry it. Next, measure the resistance (inter-terminal resistance) between a pair of terminals with a separation distance of 15 mm on the exposed plane of the electrode layer. In this measurement, when the inter-terminal resistance is 10 kΩ or less, it can be determined that the electrode layer is a crystalline layer.

[0042] The average crystal grain size in the plane direction of the electrode layer 20 (crystalline layer) is 300 nm or less, preferably 270 nm or less, more preferably 240 nm or less, still more preferably 220 nm or less, from the viewpoint of ensuring the number of carriers (number of free electrons) in the electrode layer 20 (in the electrode layer 20, the smaller the crystal grains, the greater the total length of grain boundaries and the greater the tendency for the number of carriers to increase). The average crystal grain size in the plane direction of the electrode layer 20 is, for example, 30 nm or more, preferably 100 nm or more, more preferably 150 nm or more, still more preferably 180 nm or more, even more preferably 200 nm or more, from the viewpoint of ensuring a suitable low specific resistance for the electrode of the dimming film in the electrode layer 20. The average crystal grain size in the plane direction of the electrode layer 20 is preferably 100 to 300 nm, more preferably 150 to 270 nm, still more preferably 180 to 240 nm, even more preferably 200 to 220 nm, from the viewpoint of achieving both the ensuring of the number of carriers and the low specific resistance in the electrode layer 20. Regardless of the distance from the base film 10 in the thickness direction H of the electrode layer 20, the average crystal grain size in the electrode layer 20 preferably falls within the above range. Examples of the method for adjusting the average crystal grain size of the electrode layer 20 include adjusting the composition of the electrode layer 20, adjusting the thickness of the electrode layer 20, and adjusting the film formation temperature in the transparent conductive layer formation process (Fig. 4B) described later. Adjusting the composition of the electrode layer 20 includes adjusting the composition of the target used for sputtering film formation and the ratio of the oxygen introduction amount in the transparent conductive layer formation process. The method for measuring the average crystal grain size of the electrode layer (electrode layers 20 and 40) is as described later in relation to the examples.

[0043] The electrode layer 20 has a region (particle stacking region) containing a plurality of crystal grains in the thickness direction H. The number of particles in the thickness direction H in the particle stacking region is 2, 3, or 4 or more. FIG. 2 exemplarily shows a case where the electrode layer 20 has a particle stacking region containing two crystal grains 21 in the thickness direction H. The fact that the electrode layer 20 has a particle stacking region is suitable for securing the length (total length) of the grain boundary L and securing the number of carriers in the electrode layer 20. The method for confirming that the electrode layer (electrode layers 20 and 40) has a particle stacking region is as described later with respect to the examples.

[0044] The specific resistance of the electrode layer 20 is 2.5×10 -4 Ω·cm or less, preferably 2.2×10 -4 Ω·cm or less, more preferably 2.0×10 -4 Ω·cm or less, still more preferably 1.8×10 -4 Ω·cm or less. The fact that the specific resistance of the electrode layer 20 is low is also preferable from the viewpoint of reducing the resistance of the electrode layer 20. The specific resistance of the electrode layer 20 is preferably 0.5×10 -4 Ω·cm or more, more preferably 1.0×10 -4 Ω·cm or more, still more preferably 1.3×10 -4 Ω·cm or more, even more preferably 1.5×10 -4 Ω·cm or more from the viewpoint of realizing a good crystallization rate of the transparent conductive layer (from which the electrode layer 20 is formed) in the crystallization process (FIG. 4C) described later. The specific resistance of the electrode layer 20 is preferably 0.5×10 -4 ~2.5×10 -4 Ω·cm, more preferably 1.0×10 -4 ~2.2×10 -4 Ω·cm, still more preferably 1.3×10 -4 ~2.0×10 -4 Ω·cm, even more preferably 1.5×10 -4 ~1.8×10 -4It is Ω·cm. The specific resistance of the electrode layer 20 is obtained by multiplying the surface resistance of the electrode layer 20 by the thickness. The method for obtaining the specific resistance is as described later with respect to the examples. As a method for adjusting the specific resistance of the electrode layer 20, for example, adjustment of various conditions when the electrode layer 20 is formed by sputtering can be mentioned. The conditions include, for example, the temperature of the base (substrate film 10 in this embodiment) on which the electrode layer 20 is formed, the amount of oxygen introduced into the film formation chamber, the atmospheric pressure in the film formation chamber, and the horizontal magnetic field strength on the target.

[0045] The number of carriers (number of free electrons) in the electrode layer 20 in plan view (surface direction) is preferably 10×10 15 cm -2 or more, more preferably 12×10 15 cm -2 or more, still more preferably 14×10 15 cm -2 or more, even more preferably 14.5×10 15 cm -2 or more. This number of carriers represents the number of carriers (free electrons) per unit area (1 square centimeter) in the plan view of the electrode layer 20. The number of carriers in the electrode layer 20 in plan view is preferably 100×10 15 cm -2 or less, more preferably 60×10 15 cm -2 or less, still more preferably 40×10 15 cm -2 or less, even more preferably 20×10 15 cm -2 or less. The number of carriers in the electrode layer 20 is preferably 10×10 15 ~100×10 15 cm -2 from the viewpoint of ensuring both heat insulation and visible light transmittance of the electrode layer 20, more preferably 12×10 15 ~60×10 15 cm -2 , still more preferably 14×10 15 ~40×10 15 cm -2 , even more preferably 14.5×1015 ~20×10 15 cm -2 It is. As a method for adjusting the number of carriers in the electrode layer 20, for example, adjustment of the composition of the electrode layer 20, adjustment of the thickness of the electrode layer 20, and adjustment of the film formation temperature in the transparent conductive layer formation process (FIG. 4B) described later can be mentioned. Adjustment of the composition of the electrode layer 20 includes adjustment of the composition of the target used for sputtering film formation and adjustment of the ratio of the oxygen introduction amount in the transparent conductive layer formation process. The method for measuring the number of carriers in the electrode layer (electrode layers 20 and 40) is as described later with respect to the examples.

[0046] From the viewpoint of ensuring the number of carriers in the electrode layer 20, the thickness of the electrode layer 20 is preferably 50 nm or more, more preferably 80 nm or more, still more preferably 100 nm or more, and even more preferably 120 nm or more. The fact that the electrode layer 20 is thick is also preferable from the viewpoint of reducing the resistance of the electrode layer 20. From the viewpoint of ensuring the bending resistance of the electrode layer 20 (suppression of cracking of the electrode layer 20 during bending), the thickness of the electrode layer 20 is preferably 300 nm or less, more preferably 200 nm or less, still more preferably 170 nm or less, and even more preferably 140 nm or less. From the viewpoints of ensuring the number of carriers in the electrode layer 20, reducing the resistance, and bending resistance, the thickness of the electrode layer 20 is preferably 50 to 300 nm, more preferably 80 to 200 nm, even more preferably 100 to 170 nm, and still more preferably 120 to 140 nm.

[0047] From the viewpoint of ensuring the transparency required for the light control film X in the transparent state of the light control film, the visible light transmittance of the electrode layer 20 is, for example, 50% or more, preferably 70% or more, more preferably 80% or more, and still more preferably 85% or more. Also, the visible light transmittance of the electrode layer 20 is, for example, 100% or less.

[0048] The content ratio of noble gas atoms in the electrode layer 20 is preferably 0.3 atomic % or less, more preferably 0.2 atomic % or less, still more preferably 0.1 atomic % or less, from the viewpoint of reducing the resistance (specific resistance) of the electrode layer 20, and is, for example, 0.0001 atomic % or more. Examples of noble gas atoms include argon (Ar), krypton (Kr), and xenon (Xe). The noble gas atoms are derived from, for example, the sputtering gas used in the transparent conductive layer forming step (Fig. 4B) described later (the sputtering gas is mixed in). Examples of the method for identifying the content ratio of noble gas atoms in the electrode layer 20 include fluorescence X-ray analysis and Rutherford backscattering spectrometry (RBS) (the same applies to the method for identifying the content ratio of noble gas atoms in the electrode layer 40 described later).

[0049] The dimming layer 30 is formed of a material that can reversibly change between a colored non-transparent state (light-shielding state) and a transparent state (non-light-shielding state) by the action of, for example, an electric current or an electric field. Examples of the dimming layer 30 include an electrochromic (EC) dimming layer, a dimming layer containing polymer dispersed liquid crystal (PDLC), a dimming layer containing polymer network liquid crystal (PNLC), and a suspended particle device (SPD) dimming layer.

[0050] The EC dimming layer is formed of an EC material. The EC material is a material that can reversibly change between a colored non-transparent state (light-shielding state) and a transparent state (non-light-shielding state) by electrochemical oxidation-reduction. Examples of the EC material include inorganic EC materials and organic EC materials. Examples of the inorganic EC materials include tungsten oxide, vanadium oxide, molybdenum oxide, iridium oxide, rhodium oxide, and indium nitride. Examples of the organic EC materials include polyaniline, viologen, and polyoxotungstate.

[0051] Polymer-dispersed liquid crystals have a structure in which liquid crystals are phase-separated within the polymer. Polymer-network liquid crystals have a structure in which liquid crystals are dispersed in the polymer network, and the liquid crystals in the polymer network form a continuous phase. Among these, examples of liquid crystal compounds include nematic liquid crystal compounds, smectic liquid crystal compounds, and cholesteric liquid crystal compounds. Examples of nematic liquid crystal compounds include biphenyl-based compounds, phenyl benzoate-based compounds, cyclohexylbenzene-based compounds, azoxybenzene-based compounds, azobenzene-based compounds, azomethine-based compounds, terphenyl-based compounds, biphenyl benzoate-based compounds, cyclohexylbiphenyl-based compounds, phenylpyridine-based compounds, cyclohexylpyrimidine-based compounds, and cholesterol-based compounds.

[0052] From the viewpoint of ensuring a large difference in visible light transmittance between the non-transparent state and the transparent state in the dimming film X, the thickness of the dimming layer 30 is preferably 1 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more. From the viewpoints of thinning the dimming film X and ensuring high transmittance in the transparent state, the thickness of the dimming layer 30 is preferably 200 μm or less, more preferably 100 μm or less, and still more preferably 80 μm or less. From the viewpoint of achieving both the above-mentioned visible light transmittance difference and the above-mentioned thinning and high transmittance in the dimming film X, the thickness of the dimming layer 30 is preferably 1 to 200 μm, more preferably 5 to 100 μm, and still more preferably 10 to 80 μm.

[0053] In the dimming film X, the base film 50 and the electrode layer 40 form a base film with electrodes Y2.

[0054] In this embodiment, the base film 50 includes a resin film 51 and a cured resin layer 52 in this order in the thickness direction H. The cured resin layer 52 is in contact with the resin film 51. The cured resin layer 52 forms the first surface 50a of the base film 50.

[0055] The resin film 51 is a base material that ensures the strength of the light control film X. Also, the resin film 51 is a flexible transparent resin film. Examples of the material for the resin film 51 include the materials described above as the material for the resin film 11. The surface of the resin film 51 on the side of the cured resin layer 52 may be surface-modified. The preferred thickness and preferred visible light transmittance of the resin film 51 are the same as the preferred thickness and preferred visible light transmittance described above for the resin film 11.

[0056] In this embodiment, the cured resin layer 52 is an optical adjustment layer (refractive index adjustment layer) for improving the optical properties of the light control film X. The cured resin layer 52 may have a function of blocking moisture and organic gases generated from the resin film 51 in the transparent conductive layer forming process. In this embodiment, the cured resin layer 52 is a cured product of a third curable resin composition. The third curable resin composition contains a resin. Examples of the resin of the third curable resin composition include the resins described above with respect to the first resin composition. Also, the third curable resin composition may be an ultraviolet curable resin composition or a heat curable resin composition.

[0057] From the viewpoint of improving the light transmission characteristics of the light control film X, the thickness of the cured resin layer 52 is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, and even more preferably 30 nm or more. From the viewpoint of thinning the light control film X, the thickness of the cured resin layer 52 is preferably 1000 nm or less, more preferably 100 nm or less, still more preferably 50 nm or less, and even more preferably 40 nm or less. From the viewpoint of achieving both the light transmission characteristics and thinning of the light control film X, the thickness of the cured resin layer 52 is preferably 5 to 1000 nm, more preferably 10 to 100 nm, still more preferably 20 to 50 nm, and even more preferably 30 to 40 nm.

[0058] The base film 50 may have another cured resin layer (e.g., a hard coat layer and an anti-blocking layer) on the side opposite to the cured resin layer 52 with respect to the resin film 51, similar to that described above for the base film 10. In FIG. 1, the other cured resin layer in the base film 50 is indicated by a virtual line as the cured resin layer 53.

[0059] From the viewpoint of ensuring the transparency required for the light control film X in the transparent state of the light control film, the visible light transmittance of the base film 50 is preferably 70% or more, more preferably 80% or more, and still more preferably 85% or more. The visible light transmittance of the base film 50 is, for example, 100% or less.

[0060] The base film 50 preferably has a near-infrared absorption layer and / or a near-infrared reflection layer (each layer is not shown).

[0061] In the base film 50, the near-infrared absorption layer may be disposed between the resin film 51 and the cured resin layer 52, or may be disposed on the side opposite to the cured resin layer 52 with respect to the resin film 51. The resin film 51 may be a near-infrared absorption layer or may have a multilayer structure including a near-infrared absorption layer. The near-infrared absorption layer includes, for example, a near-infrared absorber and a binder resin. Examples of the near-infrared absorber include the near-infrared absorbers described above with respect to the base film 10. Examples of the material of the binder resin include the materials described above with respect to the resin film 11.

[0062] In the base film 50, the near-infrared reflection layer may be disposed between the resin film 51 and the cured resin layer 52, or may be disposed on the side opposite to the cured resin layer 52 with respect to the resin film 51. The resin film 51 may be a near-infrared reflection layer or may have a multilayer structure including a near-infrared reflection layer. Examples of the near-infrared reflection layer include the near-infrared reflection layers described above with respect to the base film 10.

[0063] The electrode layer 40 is a layer having both light transmissibility and conductivity. The electrode layer 40 is formed of a transparent conductive material. That is, the electrode layer 40 is a transparent conductive layer. Examples of the transparent conductive material include indium-containing conductive oxides and antimony-containing conductive oxides. Examples of the 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 the antimony-containing conductive oxides include antimony tin composite oxide (ATO). From the viewpoint of achieving high transparency and good electrical conductivity, the transparent conductive material is preferably an indium-containing conductive oxide, and more preferably ITO. That is, the electrode layer 40 is preferably an indium-containing conductive oxide layer, and more preferably an ITO layer. ITO may contain a metal or a semimetal other than In and Sn in an amount less than the respective contents of In and Sn.

[0064] When the electrode layer 40 is formed of ITO, the ratio of the content of tin oxide to the total content of indium oxide (In2O3) and tin oxide (SnO2) in ITO (tin oxide ratio) is preferably 11% by mass or more, more preferably 12% by mass or more, and still more preferably 12.5% by mass or more from the viewpoint of appropriately suppressing the growth of crystal grains in the transparent conductive layer in the crystallization step (FIG. 4C) described later and ensuring the carrier number of the electrode layer 40. The tin oxide ratio in the electrode layer 40 is preferably 18% by mass or less, more preferably 16% by mass or less, and still more preferably 14% by mass or less from the viewpoint of reducing the resistance of the electrode layer 40. The tin oxide ratio in the electrode layer 40 is preferably 11 to 18% by mass, more preferably 12 to 16% by mass, and still more preferably 12.5 to 14% by mass from the viewpoint of achieving both the above-mentioned carrier number ensuring and the above-mentioned resistance reduction.

[0065] The electrode layer 40 is preferably a crystalline layer. The fact that the electrode layer 40 is a crystalline layer is preferable from the viewpoint of reducing the resistance of the electrode layer 40, and is also preferable for realizing good infrared reflection characteristics in the electrode layer 40 and the dimming film X.

[0066] From the perspective of ensuring the number of carriers (number of free electrons) in the electrode layer 40, the average crystal grain size in the plane direction of the electrode layer 40 (crystalline layer) is preferably 300 nm or less, more preferably 270 nm or less, still more preferably 240 nm or less, and even more preferably 220 nm or less (in the electrode layer 40, the smaller the crystal grains, the greater the total length of grain boundaries and the greater the number of carriers). From the perspective of ensuring the bending resistance of the electrode layer 40 (suppressing cracking of the electrode layer 40 during bending), the average crystal grain size in the plane direction of the electrode layer 40 is preferably 100 nm or more, more preferably 150 nm or more, still more preferably 180 nm or more, and even more preferably 200 nm or more. From the perspective of achieving both ensuring the number of carriers and the bending resistance of the electrode layer 40, the average crystal grain size in the plane direction of the electrode layer 40 is preferably 100 - 300 nm, more preferably 150 - 270 nm, still more preferably 180 - 240 nm, and even more preferably 200 - 220 nm. Regardless of the distance from the base film 50 in the thickness direction H of the electrode layer 40, the average crystal grain size in the electrode layer 40 preferably falls within the above range. The method for adjusting the average crystal grain size of the electrode layer 40 is the same as that described above for the method of adjusting the average crystal grain size of the electrode layer 20.

[0067] The electrode layer 40 preferably has a particle stacking region containing a plurality of crystal grains in the thickness direction H. The number of particles in the thickness direction H in the particle stacking region is 2, 3, or 4 or more. FIG. 3 exemplarily shows a case where the electrode layer 40 has a particle stacking region containing two crystal grains 41 in the thickness direction H. The fact that the electrode layer 40 has a particle stacking region is suitable for ensuring the length (total length) of the grain boundaries L and thus ensuring the number of carriers in the electrode layer 40.

[0068] From the perspective of ensuring the number of carriers (number of free electrons) in the electrode layer 40, the specific resistance of the electrode layer 40 is preferably 2.5×10 -4 Ω·cm or less, more preferably 2.2×10 -4 Ω·cm or less, still more preferably 2.0×10 -4 Ω·cm or less, and even more preferably 1.8×10 -4It is below Ω·cm. A low specific resistance of the electrode layer 40 is also preferable from the viewpoint of reducing the resistance of the electrode layer 40. From the viewpoint of realizing a good crystallization rate of the transparent conductive layer (from which the electrode layer 40 is formed) in the crystallization process, the specific resistance of the electrode layer 40 is preferably 0.5×10 -4 Ω·cm or more, more preferably 1.0×10 -4 Ω·cm or more, still more preferably 1.3×10 -4 Ω·cm or more, even more preferably 1.5×10 -4 Ω·cm or more. From the viewpoint of achieving both ensuring the number of carriers in the electrode layer 40 and the crystallization rate, the specific resistance of the electrode layer 40 is preferably 0.5×10 -4 ~2.5×10 -4 Ω·cm, more preferably 1.0×10 -4 ~2.2×10 -4 Ω·cm, still more preferably 1.3×10 -4 ~2.0×10 -4 Ω·cm, even more preferably 1.5×10 -4 ~1.8×10 -4 Ω·cm. The method for adjusting the specific resistance of the electrode layer 40 is the same as that described above for the method of adjusting the specific resistance of the electrode layer 20.

[0069] The number of carriers (number of free electrons) in the electrode layer 40 in plan view (surface direction) is preferably 10×10 15 cm -2 or more, more preferably 12×10 15 cm -2 or more, still more preferably 14×10 15 cm -2 or more, even more preferably 14.5×10 15 cm -2 or more. The number of carriers in the electrode layer 40 in plan view may be less than 10×10 15 cm -2 From the viewpoint of ensuring the visible light transmittance of the electrode layer 40, the number of carriers (number of free electrons) in the electrode layer 40 in plan view is preferably 100×10 15 cm -2 or less, more preferably 60×10 15 cm -2More preferably, it is 40×10 15 cm -2 Or less, even more preferably 20×10 15 cm -2 Or less. The number of carriers in the electrode layer 40 is preferably 10×10 15 ~100×10 15 cm -2 From the perspective of ensuring both the heat insulation property and the visible light transmittance of the electrode layer 40, more preferably 12×10 15 ~60×10 15 cm -2 Even more preferably 14×10 15 ~40×10 15 cm -2 Even more preferably 14.5×10 15 ~20×10 15 cm -2 That is. The method for adjusting the number of carriers in the electrode layer 40 is the same as that described above for the method of adjusting the number of carriers in the electrode layer 20.

[0070] From the perspective of ensuring the number of carriers in the electrode layer 40, the thickness of the electrode layer 40 is preferably 50 nm or more, more preferably 80 nm or more, even more preferably 100 nm or more, and even more preferably 120 nm or more. The fact that the electrode layer 40 is thick is also preferable from the perspective of reducing the resistance of the electrode layer 40. From the perspective of ensuring the bending resistance of the electrode layer 40 (suppressing cracking of the electrode layer 40 during bending), the thickness of the electrode layer 40 is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 170 nm or less, and even more preferably 140 nm or less. From the perspectives of the number of carriers, resistance reduction, and bending resistance of the electrode layer 40, the thickness of the electrode layer 40 is preferably 50~300 nm, more preferably 80~200 nm, even more preferably 100~170 nm, and even more preferably 120~140 nm.

[0071] From the perspective of ensuring the transparency required for the transparent state of the light control film in the light control film X, the visible light transmittance of the electrode layer 40 is, for example, 50% or more, preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. Also, the visible light transmittance of the electrode layer 40 is, for example, 100% or less.

[0072] From the perspective of reducing the resistance (specific resistance) of the electrode layer 40, the content ratio of noble gas atoms in the electrode layer 40 is preferably 0.3 atomic% or less, more preferably 0.2 atomic% or less, still more preferably 0.1 atomic% or less, and for example, 0.0001 atomic% or more. Examples of noble gas atoms include argon (Ar), krypton (Kr), and xenon (Xe). The noble gas atoms are derived from, for example, the sputtering gas used in the transparent conductive layer forming process (Figure 4B) described later (mixed with the sputtering gas).

[0073] From the perspective of ensuring the transparency of the light control film X, the visible light transmittance (in the transparent state) of the light control film X is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more. The visible light transmittance of the base film 10 is, for example, 100% or less.

[0074] From the perspective of ensuring good heat insulation performance against sunlight in the light control film X, the average transmittance of the light control film X at wavelengths from 800 nm to 1300 nm is preferably 50% or less, more preferably 40% or less, still more preferably 30% or less. The average transmittance of the light control film X is, for example, 0% or more, preferably 10% or more. The light control film X preferably has such a value of the average transmittance (wavelength 800 nm to 1300 nm) in the colored state or the transparent state, and more preferably has such a value of the average transmittance (wavelength 800 nm to 1300 nm) in both the colored state and the transparent state.

[0075] The light control film X is manufactured, for example, as follows.

[0076] First, as shown in FIG. 4A, a base film 10 is prepared. The base 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 above-mentioned first resin composition on the resin film 11 to form a coating film and then curing this coating film. When the first resin composition contains a thermosetting resin, the coating film is cured by heating. When the first resin composition contains an ultraviolet-curable resin, the coating film is cured by ultraviolet irradiation. The exposed surface of the cured resin layer 12 formed on the resin film 11 is surface-modified as necessary. When performing plasma treatment as the surface modification treatment, for example, argon gas is used as the inert gas. Also, the discharge power in the plasma treatment is, for example, 10 W or more and, for example, 5000 W or less. Further, on the side of the resin film 11 opposite to the cured resin layer 12, the above-mentioned other cured resin layer 13 (FIG. 1) may be formed.

[0077] Next, as shown in FIG. 4B, an amorphous transparent conductive layer 20' is formed on the base film 10 (transparent conductive layer forming step). Specifically, by a sputtering method, a transparent conductive material is formed into a film on the cured resin layer 12 of the base film 10 to form the transparent conductive layer 20'.

[0078] In the sputtering method, it is preferable to use a sputtering film-forming apparatus capable of implementing the film-forming process in a roll-to-roll manner. In the production of the light control film X, when using a roll-to-roll type sputtering film-forming apparatus, while running the long base film 10 from the pay-out roll provided in the apparatus to the take-up roll, a material is formed into a film on the base film 10 to form the transparent conductive layer 20'. Also, in the sputtering method, a sputtering film-forming apparatus having one film-forming chamber may be used, or a sputtering film-forming apparatus having a plurality of film-forming chambers arranged in order along the running path of the base film 10 may be used.

[0079] In the sputtering method, specifically, while introducing a sputtering gas (inert gas) under vacuum conditions into the film formation chamber provided in the sputtering film formation apparatus, a negative voltage is applied to the target disposed on the cathode in the film formation chamber. As a result, glow discharge is generated to ionize gas atoms, and the gas ions are made to collide with the target surface at high speed, ejecting the target material from the target surface, and depositing the ejected target material on the base film 10. As the target material, for example, the sintered body of the conductive oxide described above with respect to the electrode layer 20 is used. Examples of the sputtering gas include noble gas atoms. Examples of the noble gas atoms include argon (Ar), krypton (Kr), and xenon (Xe).

[0080] The sputtering method is preferably a reactive sputtering method. In the reactive sputtering method, for example, a sputtering gas (inert gas) and oxygen as a reactive gas are introduced into the film formation chamber. From the viewpoint of ensuring the number of carriers in the electrode layer 20, the ratio of the introduction amount of oxygen to the total introduction amount of the sputtering gas and oxygen introduced into the film formation chamber in the reactive sputtering method is preferably 1.5% by flow rate or more, more preferably 2.0% by flow rate or more, and still more preferably 2.2% by flow rate or more. From the viewpoint of ensuring good crystallinity of the electrode layer 20, the ratio of the introduction amount of oxygen is preferably 3.2% by flow rate or less, more preferably 2.8% by flow rate or less, and still more preferably 2.6% by flow rate or less. From the viewpoint of achieving both the number of carriers and crystallinity of the electrode layer 20, the ratio of the introduction amount of oxygen is preferably 1.5 to 3.2% by flow rate, more preferably 2.0 to 2.8% by flow rate, and still more preferably 2.2 to 2.6% by flow rate.

[0081] The atmospheric pressure in the film formation chamber during film formation (sputtering film formation) by the sputtering method is, for example, 0.02 Pa, preferably 0.1 Pa or more, more preferably 0.2 Pa or more, and is, for example, 1 Pa or less, preferably 0.7 Pa or less, more preferably 0.5 Pa or less.

[0082] In the sputtering method, the film formation temperature (the temperature of the base film 10 during sputter film formation) is preferably 50°C or lower, more preferably 30°C or lower, still more preferably 10°C or lower, even more preferably 0°C or lower, and even more preferably -5°C or lower, from the viewpoint of appropriately forming an amorphous transparent conductive layer capable of crystal growth in the subsequent crystallization step. The film formation temperature is, for example, -30°C or higher or -20°C or higher.

[0083] Examples of the power source for applying voltage to the target include a DC power source, an AC power source, an MF power source, and an RF power source. The DC power source and the RF power source may be used in combination as the power source. The absolute value of the discharge voltage during sputter film formation is, for example, 50V or higher and, for example, 500V or lower. The horizontal magnetic field intensity on the target is, for example, 10mT or higher and, for example, 100mT or lower.

[0084] Next, as shown in FIG. 4C, the transparent conductive layer 20' (FIG. 4B) on the base film 10 is crystallized by heating to form an electrode layer 20 (crystalline transparent conductive layer) (crystallization step). Thereby, the base film Y1 with electrodes is produced. Examples of the heating means include an infrared heater and an oven (a heat medium heating type oven, a hot air heating type oven). The heating temperature is preferably 100°C or higher, more preferably 120°C or higher, from the viewpoint of ensuring a high crystallization rate. The heating temperature is preferably 200°C or lower, more preferably 170°C or lower, still more preferably 150°C or lower, from the viewpoint of suppressing the influence of heating on the base film 10. The heating time is, for example, less than 600 minutes, preferably less than 120 minutes, more preferably 90 minutes or less, still more preferably 60 minutes or less, and, for example, 1 minute or more, preferably 5 minutes or more.

[0085] Next, as shown in FIG. 4D, a light control layer 30 is formed on the electrode layer 20. When an inorganic EC material is used as the material for forming the light control layer 30, for example, the inorganic EC material is formed into a film on the electrode layer 20 by a dry coating method. As the dry coating method, a sputtering method is preferable. When an organic EC material is used as the material for forming the light control layer 30, for example, the organic EC material is formed into a film on the electrode layer 20 by a wet coating method.

[0086] On the other hand, a base film Y2 with electrodes (base film 50, electrode layer 40) is produced. Specifically, it is the same as the method for producing the base film Y1 with electrodes (FIGS. 4A to 4C).

[0087] Next, as shown in FIGS. 5A and 5B, the base film Y1 with electrodes having the light control layer 30 and the base film Y2 with electrodes are integrated. Specifically, the base films Y1 and Y2 with electrodes and the light control layer 30 are integrated so that the light control layer 30 is sandwiched between the base films Y1 and Y2 with electrodes.

[0088] In the above manner, the light control film X can be manufactured. In the light control film X, the light control layer 30 is switched between a non-transparent state (light-shielding state) and a transparent state (non-light-shielding state) by turning on and off the voltage between the electrode layers 20 and 40. Such a light control film X is, for example, a light control film assembled to window glass of buildings, vehicles, etc. In the window glass with the light control film X attached, the transmittance of light such as visible light with respect to the window glass with the light control film X is switched by turning on and off the voltage between the electrode layers 20 and 40.

[0089] As described above, in the light control film X, the electrode layer 20 is an indium-containing conductive oxide layer, and 2.5×10 -4It is a crystalline layer having a specific resistance of 1 Ω·cm or less and an average crystal grain size in the plane direction of 300 nm or less, and has a particle laminated region containing a plurality of crystal grains in the thickness direction. Such a dimming film X is suitable for ensuring the number of free electrons (carrier number) per unit area in the plan view of the electrode layer 20. The larger the number of free electrons in the electrode layer 20, the higher the reflectivity of the electrode layer 20 to the heat rays in sunlight, and thus the higher the heat insulation property of the dimming film X. Therefore, the dimming film X is suitable for realizing good heat insulation property against sunlight. Such a dimming film X is suitable as an outdoor dimming film. Examples of the outdoor dimming film include a dimming film for a sunroof of a vehicle such as a private car, and a dimming film for a window of a building such as a house and a building.

[0090] As described above, preferably, the electrode layer 40 of the dimming film X is an indium-containing conductive oxide layer, having a specific resistance of 2.5×10 -4 Ω·cm or less, is a crystalline layer having an average crystal grain size in the plan view of 300 nm or less, and has a particle laminated region containing a plurality of crystal grains in the thickness direction. The dimming film X having the electrode layer 40 in addition to the electrode layer 20 is helpful for realizing good heat insulation property against sunlight in the dimming film.

Example

[0091] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples. Also, the specific numerical values such as the blending amount (content), physical property values, parameters, etc. described below can be replaced with the upper limits (numerical values defined as "or less" or "less than") or lower limits (numerical values defined as "or more" or "exceeding") of the corresponding blending amount (content), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention".

[0092] 〔Example 1〕 First, a roll of polyethylene terephthalate (PET) film (thickness: 100 μm, manufactured by Mitsubishi Chemical Corporation) as a long resin film was prepared. Next, a thermosetting resin composition C1 was applied to one surface (the first surface) of the PET film to form a coating film. The resin composition C1 contains 100 parts by mass of a melamine resin, 100 parts by mass of an alkyd resin, and 50 parts by mass of an organic silane condensate. Next, the coating film on the PET film was heated and thermoset. The heating temperature was 185°C and the heating time was 1 minute. Thereby, a first cured resin layer as an optical adjustment layer with a thickness of 35 nm was formed. Next, an ultraviolet curable resin composition C2 was applied to the other surface (the second surface) of the PET film to form a coating film. Next, the coating film was cured by ultraviolet irradiation. Thereby, a second cured resin layer as a hard coat (HC) layer with a thickness of 2 μm was formed. In the above manner, a base film (first cured resin layer / base film / second cured resin layer) was produced.

[0093] Next, an amorphous transparent conductive layer with a thickness of 125 nm was formed on the first cured resin layer in the base film by reactive sputtering (transparent conductive layer forming step). In this step, a roll-to-roll sputtering film forming apparatus (DC magnetron sputtering film forming apparatus) was used. The apparatus includes a film forming chamber capable of performing a film forming process while running a work film in a roll-to-roll manner. The conditions for sputtering film formation in this step are as follows.

[0094] In sputtering film formation, the ultimate vacuum degree in the film forming chamber is 0.5×10 -4After evacuating the inside of the sputtering film deposition apparatus to a vacuum until reaching Pa, argon (Ar) as a sputtering gas (inert gas) and oxygen as a reactive gas were introduced into the film deposition chamber, and the atmospheric pressure in the film deposition chamber was set to 0.3 Pa. The ratio of the oxygen introduction amount to the total introduction amount of argon and oxygen introduced into the film deposition chamber was set to 2.4 flow %. Also, as the target (first target), a sintered body of indium oxide and tin oxide (ITO with a tin oxide ratio of 12.5 mass %) was used. As the power supply for applying a voltage to the target, a DC power supply was used. The horizontal magnetic field strength on the target was set to 90 mT. The film deposition temperature (the temperature of the substrate film on which the transparent conductive layer is laminated) was set to -8 °C. The specific resistance of the formed transparent conductive layer (amorphous) was 6.5×10 -4 Ω·cm.

[0095] Next, the amorphous transparent conductive layer was crystallized by heating in a hot air oven (crystallization step). The heating temperature was set to 150 °C. The heating time was set to 2 hours. Thereby, a crystalline transparent conductive layer with a thickness of 125 nm was formed as an electrode layer.

[0096] As described above, a roll of the film with an electrode layer was produced. This film with an electrode layer includes a substrate film (second cured resin layer / resin film / first cured resin layer) and an electrode layer on the substrate film.

[0097] Next, two films with electrode layers were cut out from the roll of the film with an electrode layer. Next, an adhesive layer with a thickness of 25 μm was formed as a pseudo-dimming layer by applying an adhesive (product name "LUCIACS CS9861UA", manufactured by Nitto Denko Corporation) on the electrode layer of one of the films with an electrode layer (the first film with an electrode layer). Next, the electrode layer side of the other film with an electrode layer (the second film with an electrode layer) was bonded to the adhesive layer. That is, the two films with electrode layers were joined via the adhesive layer.

[0098] As described above, the laminated film of Example 1 was produced. This laminated film is a pseudo-dimming film having a laminated structure similar to that of a dimming film (this film has a pseudo form and does not have a dimming function). Specifically, the laminated film of Example 1 has, in this order in the thickness direction, a first base film, a first electrode layer with a thickness of 125 nm, a pseudo-dimming layer, a second electrode layer with a thickness of 125 nm, and a second base film.

[0099] [Comparative Example 1] A laminated film of Comparative Example 1 was produced in the same manner as the laminated film of Example 1, except for the following.

[0100] In the reactive sputtering method of the transparent conductive layer forming step, a second target was used instead of the first target, and the ratio of the oxygen introduction amount to the total introduction amount of argon and oxygen introduced into the film forming chamber was set to 3.4 flow %. The second target is a sintered body of indium oxide and tin oxide, and is ITO with a tin oxide ratio of 10.0 mass %. Also, the crystallization step was not performed.

[0101] [Comparative Example 2] A laminated film of Comparative Example 2 was produced in the same manner as the laminated film of Example 1, except for the following.

[0102] In the transparent conductive layer forming step, an amorphous transparent conductive layer (thickness: 24 nm) was formed on the first cured resin layer of the base film by the reactive sputtering method. In this step, a second target (ITO sintered body with a tin oxide ratio of 10.0 mass %) was used instead of the first target, and the film forming temperature was changed to 20 °C instead of -8 °C.

[0103] The laminated film of Comparative Example 2 has, in this order in the thickness direction, a first base film, a first electrode layer with a thickness of 24 nm, a pseudo-dimming layer, a second electrode layer with a thickness of 24 nm, and a second base film.

[0104] <Thickness of the electrode layer> The thickness of the electrode layer of the film with an electrode layer obtained in the production process of each laminated film of the examples and comparative examples was measured by observation with a field emission transmission electron microscope (FE-TEM) (FE-TEM observation). Specifically, first, samples for cross-sectional observation of each electrode layer (first samples) in the examples and comparative examples were prepared by FIB (Focused Ion Beam) processing (FIB micro-sampling method). In the FIB micro-sampling method, an FIB apparatus (product name "FB2200", manufactured by Hitachi) was used, and the acceleration voltage was set to 10 kV. Next, the cross-section of the electrode layer in the first sample was observed by FE-TEM, and the thickness of the electrode layer was measured in the observation image. In this observation, an FE-TEM apparatus (product name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200 kV. Further, in the FE-TEM observation of the electrode layer of the film with an electrode layer obtained in the production process of the laminated film of Example 1, a region containing a plurality of crystal grains (particle laminated region) could be confirmed in the thickness direction. The electrode layer of Comparative Example 1 had not undergone the crystallization process as described above and was an amorphous layer. Specifically, in the FE-TEM observation of the electrode layer of the film with an electrode layer obtained in the production process of the laminated film of Comparative Example 1, it was confirmed that the electrode was an amorphous layer, and a region containing a plurality of crystal grains (particle laminated region) could not be confirmed in the thickness direction. Also, in the FE-TEM observation of the electrode layer of the film with an electrode layer obtained in the production process of the laminated film of Comparative Example 2, a particle laminated region could not be confirmed.

[0105] 〈Specific Resistance〉 Regarding the electrode layer (transparent conductive layer) of the film with an electrode layer obtained in the production process of each laminated film of the examples and comparative examples, the specific resistance was examined. Specifically, first, the surface resistance of the electrode layer was measured by the four-terminal method in accordance with JIS K7194 (1994). Next, the specific resistance (Ω·cm) of the electrode layer was obtained by multiplying the surface resistance value by the thickness of the electrode layer. The results are shown in Table 1.

[0106] 〈Average Crystal Grain Size〉 First, a sample for observation by a transmission electron microscope (TEM) was prepared. Specifically, a thin slice was cut out from the electrode layer using an ultramicrotome (manufactured by Leica). At this time, the thin slice was cut out so that the cutting surface by the ultramicrotome was substantially parallel to the plane direction of the electrode layer. Next, this thin slice was observed (planar view observation) and photographed using a transmission electron microscope (product name "HT7820", manufactured by Hitachi High-Technologies Corporation) to obtain a TEM observation image. The magnification of the observation was set to 50000 times. Next, in the TEM observation image, after arbitrarily selecting a square region of 1.5 μm × 1.5 μm, a plurality of crystal grains contained in this region were specified, and for each crystal grain, the maximum length of the crystal grain was determined. This maximum length was defined as the grain size of the crystal grain. Next, the average value of the grain sizes of the plurality of crystal grains in the region was determined. The value is shown in Table 1 as the average crystal grain size.

[0107] 〈Number of carriers〉 The number of carriers (cm -2 ) in the electrode layer of the film with an electrode layer obtained in the production process of each laminated film of the examples and comparative examples was measured using a Hall effect measurement device (product name "HL5500PC", manufactured by Bio-Rad). The measurement results are shown in Table 1.

[0108] 〈Transmittance, reflectance〉 For each laminated film of the examples and comparative examples, the solar transmittance (Te) and solar reflectance (Re) in the wavelength range of 300 nm to 2500 nm were measured using a spectrophotometer U-4100 (manufactured by HITACHI). In this measurement, the measurement pitch was set to 5 nm. The measurement results are shown in Table 1. Solar radiation refers to radiation in the wavelength range of 300 nm to 2500 nm. The solar transmittance (Te) is calculated by a spectrophotometer from a predetermined sum calculation including the spectral transmittance and the spectral solar irradiance in the formula. The solar reflectance (Re) is calculated by a spectrophotometer from a predetermined sum calculation including the spectral reflectance and the spectral solar irradiance in the formula.

[0109] 〈Solar heat acquisition rate〉 For each of the laminated films of the examples and comparative examples, the solar heat gain factor was determined. Specifically, the solar heat gain factor of the laminated film was determined by the following formulas (1) to (3) based on ISO 13837:2021. In formula (1), Tts represents the solar heat gain factor and is an index of heat insulation performance.

[0110] Tts = Te + Qi (1) Qi = Ae ×{hi / (hi + he)} (2) Ae = 100 - Te - Re (3)

[0111] For each of the laminated films of the examples and comparative examples, formulas (1) to (3) are as follows. Tts indicates the ratio (%) of the total energy of the light (irradiation light) irradiated on the sample (laminated film) to the total energy of the energy passing through the sample when the total energy of the light irradiated on the sample is 100%. Te indicates the ratio of the energy of the light (transmitted light) transmitted through the sample among the irradiation light on the sample. The solar transmittance obtained by the above measurement was used as Te. Qi represents the secondary heat flow rate passing through the sample and is obtained by formula (2). The smaller this value, the less heat the sample conducts, meaning it has high heat insulation performance. In formula (2), Ae indicates the ratio of the energy of the irradiation light on the sample absorbed by the sample and is obtained by formula (3). hi is a parameter indicating the ease of heat transfer in the same direction as the light passing direction in the sample. 8 W / (m 2 ·K) was used as hi. he is a parameter indicating the ease of heat transfer in the direction opposite to the light passing direction in the sample. 21 W / (m 2 ·K) was used as he. In formula (3), Re indicates the ratio of the energy of the light (reflected light) reflected by the sample among the irradiation light on the sample. The solar reflectance obtained by the above measurement was used as Re.

[0112]

Table 1

Explanation of symbols

[0113] X dimming film H thickness direction Y1, Y2 substrate film with electrodes 10, 50 substrate film 11, 51 resin film 12, 52 cured resin layer 20 electrode layer (first electrode layer) 30 dimming layer 40 electrode layer (second electrode layer)

Claims

1. A dimming film comprising a base film, a first electrode layer, a dimming layer, and a second electrode layer in this order in the thickness direction, wherein the first electrode layer is an indium-containing conductive oxide layer, The first electrode layer has a specific resistance of 2.5×10 －４ Ω·cm or less, and the first electrode layer is a crystalline layer having an average crystal grain size in the plane direction of 300 nm or less and having a region containing a plurality of crystal grains in the thickness direction. A dimming film.

2. The dimming film according to claim 1, wherein the indium-containing conductive oxide is an indium tin composite oxide having a tin oxide ratio of 11% by mass or more.

3. The dimming film according to claim 1, wherein the second electrode layer is an indium-containing conductive oxide layer.

4. The dimming film according to claim 3, wherein the indium-containing conductive oxide in the second electrode layer is an indium tin composite oxide having a tin oxide ratio of 11% by mass or more.

5. The second electrode layer has a specific resistance of 2.5×10 －４ Ω·cm or less, and the dimming film according to claim 1.

6. The dimming film according to claim 1, wherein the second electrode layer is a crystalline layer having an average crystal grain size in the plane direction of 300 nm or less.

7. The dimming film according to claim 6, wherein the second electrode layer has a region containing a plurality of crystal grains in the thickness direction.

8. The dimming film according to claim 1, wherein the base film has a near-infrared absorption layer and / or a near-infrared reflection layer.

9. The dimming film according to any one of claims 1 to 8, having an average transmittance of 50% or less at a wavelength of 800 nm to 1300 nm.

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