Laminate

Abstract

To provide a laminate having a transparent conductive layer excellent in adhesion to another layer with a low specific resistance.SOLUTION: A laminate (1) includes a ground layer (3) and a transparent conductive layer (4) being crystalline neighboring one side surface (31) in a thickness direction of the ground layer (3). The ground layer (3) includes a resin. One side surface (41) in a thickness direction of the transparent conductive layer (4) includes a first protrusion (42) whose height is 3 nm or more. The one side surface (31) of the ground layer (3) may include a second protrusion whose height is 3 nm or more. The first protrusion (42) includes at least one protrusion that does not overlap the second protrusion when projected in the thickness direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminate. [Background technology]

[0002] A laminate including an underlayer and a crystalline transparent conductive layer adjacent to the underlayer is known (see, for example, Patent Document 1 below). In the laminate described in Patent Document 1, one surface in the thickness direction of the transparent conductive layer has a first protuberance. One surface in the thickness direction of the underlayer has a second protuberance. The second protuberance of the underlayer overlaps with the first protuberance of the transparent conductive layer when projected in the thickness direction.

[0003] In the manufacture of the laminate of Patent Document 1, a second protuberance corresponding to the shape of the particles is formed on the underlayer by applying a resin composition containing the particles, and a thin film is formed on one surface in the thickness direction of the underlayer to form a first protuberance following the second protuberance on the transparent conductive layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-122992 A Summary of the Invention [Problem to be solved by the invention]

[0005] The transparent conductive layer is made crystalline by heating the amorphous transparent conductive layer. However, in the laminate of Patent Document 1, due to the above-mentioned second protuberance, the orientation of the crystals is difficult to align during crystallization of the amorphous transparent conductive layer, that is, the growth of the crystals is inhibited, and therefore, there is a problem that the resistivity of the crystallized transparent conductive layer becomes high.

[0006] On the other hand, when another layer is disposed on one surface of the transparent conductive layer in the thickness direction, adhesion between the transparent conductive layer and the above-mentioned layer is also required. The other layer includes, for example, a coating layer.

[0007] The present invention provides a laminate including a transparent conductive layer that has low resistivity and excellent adhesion to other layers. [Means for solving the problem]

[0008] The present invention (1) includes a laminate comprising an underlayer and a crystalline transparent conductive layer adjacent to one surface in a thickness direction of the underlayer, wherein the underlayer contains a resin, the one surface in the thickness direction of the transparent conductive layer comprises a first protrusion having a height of 3 nm or more, and the one surface of the underlayer may comprise a second protrusion having a height of 3 nm or more, and the second protrusion does not overlap the first protrusion when projected in the thickness direction.

[0009] The present invention (2) includes the laminate according to (1), in which the number of the first ridges per unit length is greater than the number of the second ridges per unit length.

[0010] The present invention (3) includes the laminate according to (1) or (2), in which the underlayer does not include the second protrusion.

[0011] The present invention (4) includes a laminate according to any one of (1) to (3), wherein the transparent conductive layer includes a grain boundary having an edge that reaches the one surface of the transparent conductive layer, and a ridge starting portion where the first ridge starts to ridge is located at or near the edge. Effect of the Invention

[0012] The transparent conductive layer of the laminate of the present invention has low resistivity and excellent adhesion to other layers. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of a laminate of the present invention. [Diagram 2] 13 is a modified example of the laminate. [Diagram 3] 13 is a modified example of the laminate. [Figure 4] FIG. 2 is an image-processed view of a TEM photograph of Example 1. [Diagram 5] This is an image processing diagram in which auxiliary lines have been added to FIG. [Figure 6] 4 is a graph showing the relationship between the amount of oxygen introduced and the resistivity in the first reactive sputtering process. [Figure 7] FIG. 11 is a schematic cross-sectional view of Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 1. One embodiment of the laminate One embodiment of the laminate of the present invention will be described with reference to FIG.

[0015] The laminate 1 extends in a surface direction. The surface direction is perpendicular to the thickness direction. The laminate 1 has, for example, a substantially rectangular shape in a plan view. A plan view refers to a view in the thickness direction. More specifically, the laminate 1 has a sheet shape. The sheet includes a film. Note that the sheet and the film are not necessarily distinguished from each other.

[0016] In this embodiment, the laminate 1 includes a base layer 2, an undercoat layer 3, and a transparent conductive layer 4 in this order toward one side in the thickness direction. Specifically, the laminate 1 includes a base layer 2, an undercoat layer 3 disposed on one surface 21 in the thickness direction of the base layer 2, and a transparent conductive layer 4 disposed on one surface 31 in the thickness direction of the undercoat layer 3. Two layers adjacent to each other in the thickness direction are adjacent to each other.

[0017] 1.1 Base material layer 2 The substrate layer 2 is disposed on the opposite side of the underlayer 3 to the transparent conductive layer 4 in the thickness direction. The substrate layer 2 has a sheet shape. The substrate layer 2 is preferably transparent.

[0018] The material of the base layer 2 includes a resin. In other words, the base layer 2 includes a resin. Examples of the resin include polyester resin, acrylic resin, olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin, and norbornene resin. In terms of transparency and mechanical strength, the resin is preferably a polyester resin. Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, and preferably PET. The thickness of the base layer 2 is, for example, 5 μm or more, preferably 10 μm or more, and, for example, 500 μm or less, preferably 200 μm or less, and more preferably 100 μm or less.

[0019] One surface 21 in the thickness direction of the base layer 2 may have a third protuberance having a height of 3 nm or more. The height of the third protuberance is determined in the same manner as the height of the first protuberance 42 described later. The positions and number of the third protuberances in a plan view are not limited.

[0020] The total light transmittance of the base layer 2 is, for example, 70% or more, preferably 80% or more, and more preferably 85% or more. There is no upper limit for the total light transmittance of the base layer 2. The total light transmittance of the base layer 2 is determined based on JIS K 7375-2008.

[0021] 1.2 Base layer 3 The underlayer 3 is adjacent to one side in the thickness direction of the base layer 2. Specifically, the underlayer 3 is in contact with one surface 21 in the thickness direction of the base layer 2. The underlayer 3 is preferably transparent. Examples of the underlayer 3 include an optical adjustment layer and a hard coat layer. The underlayer 3 is a single layer or multiple layers.

[0022] The substrate layer 2 and the undercoat layer 3 may be referred to as a substrate 30. That is, the substrate 30 includes the substrate layer 2 and the undercoat layer 3 in this order toward one side in the thickness direction. The substrate 30 is preferably transparent. Therefore, the substrate 30 may be referred to as a transparent substrate 30.

[0023] The underlayer 3 contains a resin and may further contain particles, for example. Preferably, the underlayer 3 contains a resin but does not contain particles. In this embodiment, when the underlayer 3 does not contain the above-mentioned particles, one surface 31 in the thickness direction of the underlayer 3 does not have the second protuberance 32 (see FIG. 2), and the one surface 31 can be formed as a suitable flat surface. Examples of the resin include acrylic resin, urethane resin, melamine resin, alkyd resin, and silicone resin. If the raw material of the resin is a curable resin, the underlayer 3 is formed as a cured film.

[0024] In this embodiment, one surface 31 in the thickness direction of the underlayer 3 does not include a second protrusion 32 having a height of 3 nm or more. In other words, one surface 31 in the thickness direction of the underlayer 3 is a flat surface. Note that the flat surface is permitted to have a protrusion having a height of less than 3 nm.

[0025] In this embodiment, one surface 31 in the thickness direction of the undercoat layer 3 does not have the above-mentioned second protrusion 32 (see Figure 2), so that the crystal orientation in the transparent conductive layer 4 described next is well aligned, thereby enabling the resistivity of the transparent conductive layer 4 to be reduced.

[0026] The underlayer 3 has a thickness of, for example, 5 nm or more, preferably 10 nm or more, more preferably 30 nm or more, and for example, 10,000 nm or less, preferably 5,000 nm or less.

[0027] The total light transmittance of the underlayer 3 is, for example, 70% or more, preferably 80% or more, more preferably 85% or more. The upper limit of the total light transmittance of the underlayer 3 is not limited, and is, for example, 100% or less. The total light transmittance of the underlayer 3 is determined based on JIS K 7375-2008.

[0028] The plane direction of the substrate 30 includes a direction in which the substrate 30 undergoes thermal shrinkage after being heated. The heating temperature can be selected depending on the heat resistance of the substrate 30. The plane direction of the substrate 30 includes a direction in which the thermal shrinkage rate of the substrate 30 after being heated at 160° C. for 1 hour is, for example, 0.01% or more, preferably 0.05% or more, and for example, 1.0% or less, preferably 0.5% or less. When the thermal shrinkage rate of the base material 30 is equal to or higher than the above-mentioned lower limit and equal to or lower than the above-mentioned upper limit, cracks in the transparent conductive layer 4 can be suppressed and the first protrusions 42 described below can be formed.

[0029] 1.3 Transparent conductive layer 4 The transparent conductive layer 4 is adjacent to one side in the thickness direction of the underlayer 3. Specifically, the transparent conductive layer 4 is in contact with one surface 31 in the thickness direction of the underlayer 3. The transparent conductive layer 4 forms one surface in the thickness direction of the laminate 1. The transparent conductive layer 4 has a sheet shape extending in the planar direction. In this embodiment, the transparent conductive layer 4 is a single layer.

[0030] One surface 41 in the thickness direction of the transparent conductive layer 4 includes a first protuberance 42 having a height of 3 nm or more. The transparent conductive layer 4 includes the first protuberance 42 having a height of preferably 4 nm or more, more preferably 5 nm or more, more preferably 7 nm or more, even more preferably 10 nm or more, particularly preferably 15 nm or more, and for example, a height of 50 nm or less, preferably a height of 30 nm or less, more preferably a height of 20 nm or less. By including the first protuberance 42 having a height equal to or greater than the above lower limit and equal to or less than the above upper limit, the transparent conductive layer 4 has excellent adhesion to another layer 5 described later. The first protuberance 42 may be singular or plural, and is preferably plural from the viewpoint of improving adhesion.

[0031] In this embodiment, as described above, the number per unit length of the second protrusions 32 (see FIG. 2) is 0. Therefore, the number per unit length of the first protrusions 42 is greater than the number per unit length of the second protrusions 32 (see FIG. 2). When the number per unit length of the first protrusions 42 is greater than the number per unit length of the second protrusions 32 (see FIG. 2), the adhesion of one surface 41 in the thickness direction of the transparent conductive layer 4 is reliably improved, and the resistivity of the transparent conductive layer 4 can be reliably reduced.

[0032] Specifically, the number of first protuberances 42 per unit length is, for example, 1 protuberance / μm or more, preferably 2 protuberances / μm or more, more preferably 3 protuberances / μm or more, even more preferably 4 protuberances / μm or more, particularly preferably 5 protuberances / μm or more, and most preferably 6 protuberances / μm or more, and is, for example, 50 protuberances / μm or less, preferably 30 protuberances / μm or less, more preferably 20 protuberances / μm or less.

[0033] The number of first protrusions 42 per unit length is counted by observing the cross section of the transparent conductive layer 4 with a TEM, as will be described in the Examples below.

[0034] The average height of the first protuberances 42 is 3 nm or more, preferably 4 nm or more, more preferably 5 nm or more, even more preferably 6 nm or more, particularly preferably 7 nm or more, and for example, 40 nm or less, preferably 20 nm or less, more preferably 15 nm or less, and even more preferably 10 nm or less. The average height of the first protuberances 42 will be described later in the Examples. By providing the transparent conductive layer 4 with the first protuberances 42 having an average height that is equal to or more than the above lower limit and equal to or less than the above upper limit, the transparent conductive layer 4 has excellent adhesion to another layer 5 described later.

[0035] In this embodiment, one surface 41 in the thickness direction of the transparent conductive layer 4 further includes, for example, a flat portion 43. The flat portion 43 is disposed outside the protrusion starting portion 431. The protrusion starting portion 431 is a portion from which the first protrusion 42 starts to protrude from the flat portion 43.

[0036] The height of the first protuberance 42 is the length from one end 432 located at the most one side in the thickness direction in a cross-sectional view to a hanging point obtained by hanging down along the thickness direction from the one end 432 to a line segment connecting the two protuberance starting portions 431. The height of the first protuberance 42 can be obtained, for example, by observing a TEM photograph (cross-sectional observation).

[0037] Furthermore, the transparent conductive layer 4 is crystalline. Preferably, the transparent conductive layer 4 does not include an amorphous region. Preferably, the transparent conductive layer 4 is composed of only a crystalline region.

[0038] Whether the transparent conductive layer 4 is crystalline or amorphous can be determined, for example, by the following test: The transparent conductive layer 4 is immersed in a 5% by mass aqueous hydrochloric acid solution for 15 minutes, washed with water and dried, and the two-terminal resistance over a distance of about 15 mm is measured on one side 41 of the transparent conductive layer 4. If the two-terminal resistance is 10 kΩ or less, the transparent conductive layer 4 is crystalline, and if the two-terminal resistance exceeds 10 kΩ, the transparent conductive layer 4 is amorphous.

[0039] The crystalline transparent conductive layer 4 can have a sufficiently low resistivity.

[0040] The transparent conductive layer 4 has grain boundaries 44. The grain boundaries 44 include one edge 441 that reaches one surface 41 of the transparent conductive layer 4 in the thickness direction.

[0041] The grain boundaries 44 described above extend from each of the two one end edges 441 to the other side in the thickness direction, and are connected to each other at the intermediate portion in the thickness direction.

[0042] In addition, the grain boundary 44 may further include another edge 442 extending from the above-mentioned one edge 441 toward the other side in the thickness direction and reaching the other surface in the thickness direction of the transparent conductive layer 4, i.e., one surface 31 in the thickness direction of the underlayer 3.

[0043] Preferably, the grain boundary 44 does not include the other end edge 442, and one grain boundary 44 includes two one end edges 441. According to this configuration, the first protrusion 42 is easily formed on the one surface 41 of the transparent conductive layer 4.

[0044] The above-mentioned bulge starting portion 431 is located, for example, at the one end edge 441 and / or in the vicinity of the one end edge 441.

[0045] 1 are located at the above-described one edge 441. Although not shown, the one edge 441 corresponding to the above-described first protrusion 42A has, for example, an endless shape in a plan view, and the above-described protrusion starting portion 431A of the first protrusion 42A exists along the above-described one edge 441 in a plan view.

[0046] 1, the left ridge start portion 431B is located near one edge 441 of the grain boundary 44 including one edge 441 and the other edge 442. Nearby means, for example, that the distance between the two is within 15 nm, preferably within 10 nm. The remaining ridge start portion 431B is located at one edge 441.

[0047] When the protrusion starting portion 431 is located at and / or in the vicinity of one end edge 441 of the grain boundary 44, a large number of the first protrusions 42 are reliably formed on one surface 41 of the transparent conductive layer 4. Therefore, the adhesion of the one surface 41 of the transparent conductive layer 4 is excellent.

[0048] Examples of materials for the transparent conductive layer 4 include metal oxides. The metal oxides include at least one metal selected from the group consisting of In, Sn, Zn, Ga, Sb, Nb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. Specifically, preferred materials for the transparent conductive layer 4 include indium zinc composite oxide (IZO), indium gallium zinc composite oxide (IGZO), indium gallium composite oxide (IGO), indium tin composite oxide (ITO), and antimony tin composite oxide (ATO), and preferably indium tin composite oxide (ITO) is used from the viewpoint of reducing the resistivity.

[0049] The content of tin oxide (SnO2) in the indium tin composite oxide is, for example, 0.5 mass% or more, preferably 3 mass% or more, more preferably 6 mass% or more, and for example, less than 50 mass%, preferably 25 mass% or less, more preferably 15 mass% or less.

[0050] The transparent conductive layer 4 has a thickness of, for example, 15 nm or more, preferably 35 nm or more, more preferably 50 nm or more, even more preferably 75 nm or more, particularly preferably 100 nm or more, and particularly preferably 120 nm or more. If the thickness of the transparent conductive layer 4 is equal to or greater than the above-mentioned lower limit, the grain boundary 44 does not include the other end edge 442, and one grain boundary 44 is likely to include two one end edges 441. Therefore, the transparent conductive layer 4 can be reliably provided with the above-mentioned first protuberance 42.

[0051] The thickness of the transparent conductive layer 4 is the length in the thickness direction between one surface 31 (flat surface) of the underlayer 3 and a flat portion 43 on one surface 41 of the transparent conductive layer 4 in the thickness direction.

[0052] The transparent conductive layer 4 has a thickness of, for example, 500 nm or less, preferably 300 nm or less, and more preferably 200 nm or less.

[0053] The thickness of the transparent conductive layer 4 is measured by TEM observation (cross-sectional observation).

[0054] The transparent conductive layer 4 has a total light transmittance of, for example, 60% or more, preferably 80% or more, and more preferably 85% or more. The upper limit of the total light transmittance of the transparent conductive layer 4 is not limited and is, for example, 100% or less. The total light transmittance of the transparent conductive layer 4 is determined based on JIS K 7375-2008.

[0055] The resistivity of one surface 41 in the thickness direction of the transparent conductive layer 4 is, for example, 3.0×10 -4 Ω cm or less, preferably 2.5×10 -4 Ω cm or less, more preferably 2.3×10 -4Ω·cm or less, and more preferably 2.2×10 -4 Ω cm or less, and more preferably 2.0×10 -4 Ω·cm or less, particularly preferably 1.9×10 -4 The resistivity of one surface 41 of the transparent conductive layer 4 in the thickness direction is, for example, 0.1×10 -4 Ω cm or more, preferably 0.5×10 -4 Ω cm or more, more preferably 1.0×10 -4 Ω cm or more, more preferably 1.1×10 -4 Resistivity is measured by the four-terminal method.

[0056] Next, a method for producing the laminate 1 will be described. In this method, each layer is arranged by a roll-to-roll method.

[0057] First, a long base layer 2 is prepared.

[0058] Next, a resin composition containing the above-mentioned resin is applied to one surface 21 of the base layer 2. Thereafter, when the resin composition contains a curable resin, the curable resin is cured by heat or ultraviolet light irradiation. In this manner, a base material 30 having the base layer 2 and the underlayer 3 in order toward one side in the thickness direction is prepared. In this embodiment, since the resin composition contains a resin but does not contain particles, the above-mentioned second protuberance 32 (see FIG. 2) is not formed on one surface 31 in the thickness direction of the underlayer 3.

[0059] For example, the heat shrinkage rate of the substrate 30 in the longitudinal direction (MD direction) when heated at 160° C. for 1 hour is not limited, and is, for example, 0.1% or more, preferably 0.2% or more, and for example, 2.0% or less, preferably 1.0% or less. The heat shrinkage rate of the substrate 30 in the width direction (direction perpendicular to the longitudinal direction and thickness direction) (TD direction) when heated at 160° C. for 1 hour is not limited, and is, for example, −0.2% or more, preferably 0.00% or more, more preferably 0.01% or more, even more preferably 0.05% or more, and for example, 1.0% or less, preferably 0.5% or less.

[0060] The thermal shrinkage rate of the base material 30 is calculated by the following formula. Heat shrinkage rate (%) of the base material 30 = 100 × [length of the base material 30 before heating - length of the base material 30 after heating] / length of the base material 30 before heating

[0061] Thereafter, the transparent conductive layer 4 is formed on one surface 31 in the thickness direction of the underlayer 3. The method for forming the transparent conductive layer 4 includes, for example, a first step and a second step.

[0062] In the first step, the amorphous transparent conductive layer 40 is formed on one surface 31 in the thickness direction of the underlayer 3. The amorphous transparent conductive layer 40 is formed on one surface 31 in the thickness direction of the underlayer 3 by, for example, sputtering, preferably reactive sputtering.

[0063] In the sputtering, a sputtering device is used. The sputtering device includes a film-forming roll. The film-forming roll includes a cooling device. The cooling device is capable of cooling the film-forming roll. The film-forming roll is capable of cooling the underlayer 3 (base material 30 including the underlayer 3).

[0064] In sputtering (preferably reactive sputtering), the above-mentioned metal oxide (sintered body) is used as a target. The surface temperature of the film-forming roll corresponds to the film-forming temperature in sputtering. The film-forming temperature is, for example, 10.0°C or less, preferably 0.0°C or less, more preferably -2.5°C or less, even more preferably -5.0°C or less, even more preferably -7.0°C or less, and for example, -50°C or more, preferably -20°C or more, even more preferably -10°C or more.

[0065] If the surface temperature of the film-forming roll is equal to or lower than the above-mentioned upper limit, the underlayer 3 (including the substrate 30) can be sufficiently cooled, and therefore it is easy to obtain a transparent conductive layer 4 in which the grain boundary 44 does not include the other end edge 442 and one grain boundary 44 includes two one end edges 441. Therefore, the first protrusion 42 can be reliably formed on one surface 41 of the transparent conductive layer 4.

[0066] The sputtering gas may be a rare gas. The rare gas may be, for example, Ar. The sputtering gas may be mixed with a reactive gas. The reactive gas may be, for example, oxygen. The ratio of the amount of reactive gas introduced to the total amount of sputtering gas and reactive gas introduced is, for example, 0.1 flow% or more, preferably 0.5 flow% or more, more preferably 1.5 flow% or more, even more preferably 2.0 flow% or more, particularly preferably 2.5 flow% or more, and, for example, 5 flow% or less, preferably 3 flow% or less.

[0067] The amorphous transparent conductive layer 40 formed in the first step may not include the first protrusions 42, or may already include the first protrusions 42.

[0068] In the second step, the amorphous transparent conductive layer 40 is crystallized to form a crystalline transparent conductive layer 4. Specifically, in the second step, the amorphous transparent conductive layer 40 is heated.

[0069] The heating temperature is, for example, 80° C. or higher, preferably 110° C. or higher, more preferably 130° C. or higher, and even more preferably 150° C. or higher, and, for example, 200° C. or lower, preferably 180° C. or lower, more preferably 175° C. or lower, and even more preferably 170° C. or lower. The heating time is, for example, 1 minute or longer, preferably 3 minutes or longer, and more preferably 5 minutes or longer, and, for example, 5 hours or shorter, preferably 3 hours or shorter, and more preferably 2 hours or shorter. Heating is carried out, for example, in an air atmosphere.

[0070] In this way, a laminate 1 is manufactured which includes the base layer 2, the underlayer 3, and the transparent conductive layer 4 in this order towards one side in the thickness direction.

[0071] For example, the heat shrinkage rate of the laminate 1 in the longitudinal direction (MD direction) when heated at 160° C. for 1 hour is not limited, and is, for example, 0.1% or more, preferably 0.2% or more, and for example, 2.0% or less, preferably 1.0% or less. The heat shrinkage rate of the laminate 1 in the width direction (direction perpendicular to the longitudinal direction and thickness direction) (TD direction) when heated at 160° C. for 1 hour is not limited, and is, for example, −0.2% or more, preferably 0.00% or more, more preferably 0.01% or more, even more preferably 0.05% or more, and for example, 1.0% or less, preferably 0.5% or less.

[0072] If the thermal shrinkage rate of the laminate 1 in each of the MD and TD directions is equal to or greater than the above-mentioned lower limit, the first protrusion 42 can be reliably formed on one surface 41 of the transparent conductive layer 4.

[0073] The heat shrinkage rate of the laminate 1 is calculated by the following formula. Heat shrinkage rate (%) of laminate 1 = 100 × [length of laminate 1 before heating - length of laminate 1 after heating] / length of laminate 1 before heating

[0074] The total light transmittance of the laminate 1 is, for example, 60% or more, preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. The upper limit of the total light transmittance of the laminate 1 is not limited, and is, for example, 100% or less. The total light transmittance of the base layer 2 is, for example, 100% or less according to JIS This is required in accordance with K 7375-2008.

[0075] Thereafter, if necessary, another layer 5 is disposed on one surface in the thickness direction of the laminate 1, i.e., one surface 41 in the thickness direction of the transparent conductive layer 4. For example, a coating layer 51 is formed by coating. The other layer 51 includes, for example, a light control functional coating layer and a metal paste layer. The other layer 5 is adjacent to one surface 41 in the thickness direction of the transparent conductive layer 4. Specifically, the other layer 5 is a functional member such as a light control functional layer (voltage-driven light control coating such as PDLC, PNLC, and SPD, or current-driven light control coating such as electrochromic (EC)) or a metal paste containing silver, copper, titanium, or the like.

[0076] 2. Use of Laminate 1 The laminate 1 is used, for example, in an article. Specifically, the laminate 1 is an optical laminate, and the above-mentioned article includes an optical article. Specifically, the article includes, for example, a touch sensor, an electromagnetic wave shield, a light control element, a photoelectric conversion element, a heat ray control member, a light-transmitting antenna member, a light-transmitting heater member, an image display device, and a lighting device.

[0077] 3. Effects of one embodiment In the laminate 1, the underlayer 3 does not include the second protrusion 32 (see FIG. 2). Therefore, the crystal orientation of the crystalline transparent conductive layer 4 can be properly aligned. Therefore, the resistivity of the transparent conductive layer 4 can be sufficiently reduced.

[0078] Moreover, one surface 41 in the thickness direction of the transparent conductive layer 4 is provided with a first protrusion 42. Therefore, the transparent conductive layer 4 has excellent adhesion to another layer 5 due to the anchor effect based on the first protrusion 42.

[0079] 4. Modifications In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, each modification can achieve the same effects as those in the above-described embodiment, unless otherwise specified. Furthermore, the embodiment and the modifications can be appropriately combined.

[0080] 2, in the laminate 1 of the modified example, one surface 31 in the thickness direction of the underlayer 3 is provided with a second protrusion 32 having a height of 3 nm or more. That is, in the laminate of the present invention, one surface in the thickness direction of the underlayer may be provided with a second protrusion having a height of 3 nm or more, but such second protrusion does not overlap with the first protrusion when projected in the thickness direction.

[0081] In the laminate 1 of the modified example, the above-mentioned second protrusion 32 does not overlap with the first protrusion 42 of the transparent conductive layer 4 when projected in the thickness direction.

[0082] The number of first protrusions 42 per unit length is, for example, greater than the number per unit length of second protrusions 32. When the number of first protrusions 42 per unit length is greater than the number per unit length of second protrusions 32, the adhesion of one surface 41 in the thickness direction of transparent conductive layer 4 is reliably improved and the resistivity of transparent conductive layer 4 can be reliably reduced.

[0083] Specifically, the number of second protuberances 32 per unit length is, for example, 25 pieces / μm or less, preferably 20 pieces / μm or less, more preferably 10 pieces / μm or less, even more preferably 5 pieces / μm or less, and for example, 0 pieces / μm or 1 piece / μm or more.

[0084] The ratio of the number of second ridges 32 per unit length to the number of first ridges 42 per unit length is, for example, 0.9 or less, preferably 0.5 or less, more preferably 0.3 or less, even more preferably 0.2 or less, and particularly preferably 0.1 or less. The ratio of the number of second ridges 32 per unit length to the number of first ridges 42 per unit length is, for example, 0.0001 or more.

[0085] The value obtained by subtracting the number of second ridges 32 per unit length from the number of first ridges 42 per unit length is, for example, 1 ridge / μm or more, preferably 2 ridges / μm or more, more preferably 5 ridges / μm or more, even more preferably 7 ridges / μm or more, and particularly preferably 10 ridges / μm or more. The value obtained by subtracting the number of second ridges 32 per unit length from the number of first ridges 42 per unit length is, for example, 30 ridges / μm or less.

[0086] The method for providing the above-mentioned second protuberances 32 on the undercoat layer 3 is not particularly limited.

[0087] For example, as shown in Figure 7, when the second protrusion 32 overlaps with the first protrusion 42 of the transparent conductive layer 4 when projected in the thickness direction, the crystal orientation in the transparent conductive layer 4 is less likely to be aligned during crystallization of the first protrusion 42, i.e., crystal growth is inhibited, and as a result, the resistivity of the transparent conductive layer 4 increases.

[0088] However, in the laminate 1 of this modified example, as shown in FIG. 2, the second protrusion 32 does not overlap with the first protrusion 42 of the transparent conductive layer 4 when projected in the thickness direction, so that the above-mentioned problem does not occur and the resistivity of the transparent conductive layer 4 can be reduced.

[0089] Among the embodiments and the modified examples, the embodiment is preferred. In the embodiment, as shown in FIG. 1, one surface 31 of the underlayer 3 does not include the second protuberance 32, so that the orientation of the crystals in the transparent conductive layer 4 can be further improved. Therefore, the resistivity of the transparent conductive layer 4 can be sufficiently reduced.

[0090] As shown in FIG. 3, the laminate 1 does not include a base layer 2, but includes an underlayer 3 and a transparent conductive layer 4. EXAMPLES

[0091] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the examples and comparative examples. The specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (a numerical value defined as "not more than" or "less than") or lower limit (a numerical value defined as "not less than" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention".

[0092] Example 1 A UV-curable resin was applied to one surface 21 in the thickness direction of the substrate layer 2 made of a long PET film (thickness 50 μm, manufactured by Toray Industries, Inc.) to form a coating film. The UV-curable resin composition contains an acrylic resin. Next, the coating film was cured by UV irradiation to form the undercoat layer 3. The thickness of the undercoat layer 3 was 2 μm. In this way, a substrate 30 was produced which includes the substrate layer 2 and the undercoat layer 3 in that order in the thickness direction.

[0093] Next, an amorphous transparent conductive layer 40 was formed on one surface 31 in the thickness direction of the underlayer 3 by reactive sputtering (first step). In the reactive sputtering, a DC magnetron sputtering device was used.

[0094] The sputtering conditions in this example are as follows. A sintered body of indium oxide and tin oxide was used as the target. The tin oxide concentration in the sintered body was 10 mass %. A voltage was applied to the target using a DC power source. The horizontal magnetic field strength on the target was 90 mT. The film formation temperature was -8°C. In this application, the film formation temperature is the surface temperature of the film formation roll, and is the same as the temperature of the substrate 30. In addition, the ultimate vacuum in the film formation chamber of the DC magnetron sputtering device was 0.6×10 -4 After evacuating the film formation chamber until the pressure reached 0.4 Pa, Ar as a sputtering gas and oxygen as a reactive gas were introduced into the film formation chamber, and the pressure in the film formation chamber was set to 0.4 Pa. The ratio of the amount of oxygen introduced to the total amount of Ar and oxygen introduced into the film formation chamber was about 2.6 flow %. As shown in FIG. 6, the amount of oxygen introduced was within region R of the resistivity vs. oxygen introduction amount curve, and was set so that the resistivity of the amorphous transparent conductive layer 40 was 6.4×10 -4 The resistivity vs. oxygen introduction amount curve shown in Fig. 6 was created by investigating in advance the dependency of the resistivity of the amorphous transparent conductive layer 40 on the amount of oxygen introduction when the amorphous transparent conductive layer 40 was formed by a reactive sputtering method under the same conditions as above except for the amount of oxygen introduction.

[0095] Next, the amorphous transparent conductive layer 40 was crystallized by heating in a hot air oven (second step). The heating temperature was 160° C., and the heating time was 1 hour. The thickness of the crystalline transparent conductive layer 4 was 145 nm. The thickness of the transparent conductive layer 4 will be described later.

[0096] In this way, a laminate 1 was produced having the base layer 2, the underlayer 3, and the crystalline transparent conductive layer 4 in that order on one surface in the thickness direction (see FIG. 1).

[0097] Example 2 A laminate 1 was produced in the same manner as in Example 1. However, the ratio of the amount of oxygen introduced to the total amount of Ar and oxygen introduced into the film formation chamber was changed to about 1.3 flow %, and the thickness of the transparent conductive layer 4 was changed to 56 nm.

[0098] Comparative Example 1 A laminate 1 was produced in the same manner as in Example 1. However, the film formation temperature was changed to 80° C., the ratio of the amount of oxygen introduced to the total amount of Ar and oxygen introduced into the film formation chamber was changed to about 1.6 flow %, and the thickness of the transparent conductive layer 4 was changed to 32 nm.

[0099] Comparative Example 2 Laminate 1 was produced in the same manner as in Comparative Example 1. However, an ultraviolet-curable resin composition containing an acrylic resin and silica particles with a particle size of 20 nm was used (see FIG. 7).

[0100] <Evaluation> The transparent conductive layer 4 of each of the Examples and Comparative Examples was evaluated for the following items. The results are shown in Table 1.

[0101] [Thickness of transparent conductive layer 4] The thickness of the transparent conductive layer 4 of each laminate 1 in each Example and Comparative Example was measured by FE-TEM observation. Specifically, first, a cross-sectional observation sample of each transparent conductive layer 4 in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 was prepared by FIB microsampling. In the FIB microsampling method, an FIB device (product name "FB2200", manufactured by Hitachi) was used, and the acceleration voltage was set to 10 kV. Next, the thickness of the transparent conductive layer 4 in the cross-sectional observation sample was measured by FE-TEM observation. In the FE-TEM observation, an FE-TEM device (product name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200 kV.

[0102] [Cross-sectional observation of the first protuberance 42 and the second protuberance 32, and counting the number of first protuberances 42] After the cross section of the transparent conductive laminate of each Example and Comparative Example was adjusted by FIB microsampling, the cross section of each base layer 3 and transparent conductive layer 4 was observed by FE-TEM to confirm the presence of each of the first protuberances 42 and the second protuberances 32. In addition, the number of first protuberances 42 present within a length of 1 μm on one surface 41 in the thickness direction of the transparent conductive layer 4 was counted. The observation magnification was set so that the presence or absence and height of the first protuberances 42 and the second protuberances 32 could be observed.

[0103] The apparatus and measurement conditions are as follows. FIB equipment: Hitachi FB2200, Acceleration voltage: 10kV FE-TEM equipment: JEOL JEM-2800, accelerating voltage: 200kV

[0104] As a result, in each of Example 1 and Example 2, the first protuberance 42 was observed, but the second protuberance 32 was not observed.

[0105] The height of the highest protuberance among the first protuberances 42 in Example 1 was 15 nm. The average height of the first protuberances 42, which was determined by arbitrarily selecting 10 first protuberances 42 in Example 1, was 7 nm. In other words, the average height of the first protuberances 42 was determined as the average of the heights of the arbitrarily selected 10 first protuberances 42. FIG. 5 shows a diagram in which the grain boundaries 44 in FIG. 4 are depicted by dashed lines.

[0106] The height of the highest protuberance was 14 nm among the first protuberances 42 in Example 2. The average height of the first protuberances 42, which was determined by arbitrarily selecting 10 first protuberances 42 in Example 2, was 5 nm.

[0107] In Comparative Example 1, neither the first protuberance 42 nor the second protuberance 32 was observed.

[0108] In Comparative Example 2, both the first protuberance 42 and the second protuberance 32 were observed (see FIG. 7). The height of each of the first protuberance 42 and the second protuberance 32 in Comparative Example 2 was 11 nm.

[0109] Additionally, the number of first protrusions 42 per unit length was counted for each of Example 1, Example 2, and Comparative Example 1. As a result, it was 7 protrusions / μm in Example 1, 2 protrusions / μm in Example 2, and 5 protrusions / μm in Comparative Example 2.

[0110] [Resistance characteristics of transparent conductive laminates] The resistivity of one surface 41 in the thickness direction of the transparent conductive layer 4 of each example and comparative example was measured by the four-terminal method in accordance with JIS K7194 (1994), and then multiplied by the thickness of each example to obtain the resistivity value.

[0111] [Thermal shrinkage rate of the substrate 30 and the laminate 1] The heat shrinkage rate of the substrate 30 of Example 1 was measured after heating at 160° C. for 1 hour. As a result, the heat shrinkage rate of the substrate 30 in the MD direction was 0.5%, and the heat shrinkage rate of the laminate 1 in the TD direction was 0.1%.

[0112] The thermal shrinkage of the laminate 1 of Example 1 was measured after heating at 160° C. for 1 hour. As a result, the thermal shrinkage of the laminate 1 in the MD direction was 0.3%, and the thermal shrinkage of the laminate 1 in the TD direction was 0.1%.

[0113] [Table 1]

[0114] The above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be interpreted as being limited. Modifications of the present invention that are obvious to those skilled in the art are included in the scope of the following claims. [Industrial Applicability]

[0115] The laminate is used in optical articles. [Explanation of symbols]

[0116] 1. Laminate 3 Base layer 31 One side of the base layer in the thickness direction 32 Second uplift 4 Transparent conductive layer 41 One side of the transparent conductive layer in the thickness direction 42 1st prominence 431 Start of upheaval 44 Grain boundaries 441 One edge

Claims

1. A laminate comprising a base layer and a crystalline transparent conductive layer adjacent to one surface in the thickness direction of the base layer, wherein the base layer contains a resin, the material of the transparent conductive layer is indium tin composite oxide, one surface in the thickness direction of the transparent conductive layer is provided with a first protrusion having a height of 3 nm or more, the one surface of the base layer may be provided with a second protrusion having a height of 3 nm or more, the laminate, wherein the first protrusion includes at least one protrusion that does not overlap the second protrusion when projected in the thickness direction.

2. The laminate according to claim 1, wherein the number per unit length of the first protrusion is larger than the number per unit length of the second protrusion.

3. The transparent conductive layer includes grain boundaries having edges reaching the one surface of the transparent conductive layer, the laminate according to claim 1 or claim 2, wherein a protrusion start portion where the first protrusion starts to protrude is located at or near the edge.

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