Conductive sheet and manufacturing method thereof

Abstract

To provide a conductive sheet provided with a conductive thin film having excellent transferability from a substrate and a method for producing the same.SOLUTION: A conductive sheet 100 has a substrate 20, and a particle layer 10 comprising bound particles containing transition metal deposited on the substrate, the particle layer having openings. The contact rate of the substrate and the particle layer is 0.01% or more and 20% or less. A method for producing a conductive sheet includes a plasma treatment step for forming a particle layer by reacting a precursor thin film with plasma for 150 seconds or longer and 2000 seconds or shorter in the presence of a gas with a partial pressure of 10 Pa or more and 1000 Pa or less, containing both hydrogen atoms and oxygen atoms, for example, water molecules.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a conductive sheet and a method for producing the same. [Background technology]

[0002] Conductive thin films composed of transition metals and / or transition metal compounds are used in various electronic devices and are industrially useful. In particular, conductive thin films of transition metals and / or transition metal compounds produced by a method including a precursor coating step are desirable from the viewpoint of large-scale production.

[0003] Moreover, a conductive thin film having a pattern is desirable from the viewpoint of having various functions. For example, it is known that a conductive thin film having a fine line pattern can be made transparent.

[0004] For example, Patent Document 1 discloses a method for producing a conductive substrate including a conductive thin film in which a dispersion of metal or metal compound particles is printed on a substrate and then fired to fuse at least the outermost metal particles, and the firing is performed by exposing the substrate to plasma of a gas containing hydrogen molecules. In this way, by using a plasma treatment for firing, even copper, which has a relatively high melting point, can be sintered. Patent Document 1 also discloses that oxides that remain unreduced during the firing process contribute to the adhesion between the conductive thin film thus formed and the substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5354037 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method using plasma disclosed in Patent Document 1, although it is possible to form a conductive thin film that is excellent in adhesion between the conductive thin film and the substrate and therefore excellent in retention on the substrate, the size and shape of the obtained conductive thin film may be limited by the size and shape of the plasma reactor. In addition, the type of substrate is also limited because it is necessary to select one that can withstand a reaction with high-energy plasma.

[0007] Therefore, there is a demand for a method for manufacturing a conductive sheet that is not restricted by plasma reactors and can provide a conductive sheet with greater freedom in shape, and a method for manufacturing a conductive sheet that is not restricted by substrates and can form a conductive thin film even on substrates that are difficult to use for plasma treatment.

[0008] The present invention has been made in consideration of the above problems, and has an object to provide a conductive sheet having a conductive thin film that has excellent transferability from a substrate, and a method for manufacturing the same. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems, and as a result, have found that a particle layer (conductive thin film) with excellent transferability from a substrate can be formed by passing through a specific process, thereby solving the above problems, and have completed the present invention.

[0010] That is, the present invention is as follows. [1] A substrate; a particle layer having transition metal-containing particles bonded thereto, the particle layer being laminated on the substrate; The contact rate between the substrate and the particle layer is 0.01% or more and 20% or less. Conductive sheet. [2] The particle layer forms a continuous pattern having openings. The conductive sheet according to [1]. [3] The opening ratio of the particle layer to the substrate is 20% or more and 99% or less. The conductive sheet according to [2]. [4] The diameter of the largest inscribed circle that fills the opening is 0.5 μm or more and 1000 μm or less. The conductive sheet according to [2] or [3]. [5] The pattern is a pattern formed by intersecting a plurality of thin lines. The conductive sheet according to any one of [2] to [4]. [6] The line width of the thin line is 100 nm or more and 1000 μm or less. The conductive sheet according to [5]. [7] The pitch of the thin lines is 1.0 μm or more and 1000 μm or less. The conductive sheet according to [5] or [6]. [8] The particle layer has a thickness of 30 nm or more and 1000 μm or less. The conductive sheet according to any one of [1] to [7]. [9] an average height of the voids, which is obtained by dividing the area of ​​the voids between the substrate and the particle layer by the width of the particle layer, is 30 nm or more and 200 nm or less; The conductive sheet according to any one of [1] to [8].

[10] The average atomic concentration of oxygen in the particle layer is 10% or less. The conductive sheet according to any one of [1] to [9].

[11] The substrate has a plurality of layers. The conductive sheet according to any one of [1] to

[10] .

[12] The substrate has a surface layer containing a silicon compound. The conductive sheet according to any one of [1] to

[11] .

[13] The substrate is a plastic. The conductive sheet according to any one of [1] to

[12] .

[14] The plastic is polyethylene terephthalate. The conductive sheet according to

[13] .

[15] The transition metal comprises a metal of Group 11 of the IUPAC Periodic Table; The conductive sheet according to any one of [1] to

[14] .

[16] The transition metal comprises copper. The conductive sheet according to

[15] .

[17] The average particle size of the particles contained in the particle layer is 1.0 nm or more and 500 nm or less. The conductive sheet according to any one of [1] to

[16] .

[18] Visible light transmittance is 70% or more and 99% or less. The conductive sheet according to any one of [1] to

[17] .

[19] Sheet resistance is 0.001 Ω cm -2 More than 20Ωcm -2 Below is the The conductive sheet according to any one of [1] to

[18] .

[20] The conductive sheet according to any one of [1] to

[19] is provided. Touch panel. 〔twenty one〕 The conductive sheet according to any one of [1] to

[19] is provided. display. 〔twenty two〕 The conductive sheet according to any one of [1] to

[19] is provided. Heater. 〔twenty three〕 The conductive sheet according to any one of [1] to

[19] is provided. Electromagnetic wave shielding. 〔twenty four〕 The conductive sheet according to any one of [1] to

[19] is provided. antenna. 〔twenty five〕 a film forming step of forming a precursor thin film on a substrate; and a plasma treatment step of reacting the precursor thin film with plasma for 150 seconds to 2000 seconds in the presence of a gas containing molecules containing both hydrogen atoms and oxygen atoms at a partial pressure of 10 Pa to 1000 Pa to form a particle layer. A method for manufacturing a conductive sheet.

[26] The molecule containing both a hydrogen atom and an oxygen atom is a water molecule. A method for producing the conductive sheet according to

[25] .

[27] The precursor thin film forms a continuous pattern having openings. A method for producing a conductive sheet according to

[25] or

[26] .

[28] The aperture ratio of the precursor thin film to the substrate is 20% or more and 99% or less. A method for producing a conductive sheet according to any one of

[25] to

[27] .

[29] In the plasma treatment step, microwave plasma is used. A method for producing a conductive sheet according to any one of

[25] to

[28] .

[30] A transfer step of transferring the particle layer of the conductive sheet according to any one of [1] to

[19] to a transfer substrate, A method for producing a transfer conductive sheet.

[31] The surface free energy of the transfer substrate is 5 mN / m or more and 100 mN / m or less. A method for producing a transfer conductive sheet according to

[30] .

[32] The tensile modulus of the transfer substrate is 0.1 GPa or more and 1000 GPa or less. A method for producing a transfer conductive sheet according to

[30] or

[31] . Effect of the Invention

[0011] According to the present invention, it is possible to provide a conductive sheet having a conductive thin film that has excellent transferability from a substrate, and a method for producing the same. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing an example of a conductive sheet according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic top view illustrating an example of a conductive sheet according to the present embodiment. [Diagram 3] 2A to 2C are schematic diagrams illustrating a method for producing a transfer conductive sheet according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited to this, and various modifications are possible without departing from the gist of the present invention. In the drawings, the same elements are given the same symbols, and duplicated explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings, unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0014] 1.Conductive sheet The conductive sheet of the present embodiment includes a substrate and a particle layer laminated on the substrate and in which particles containing a transition metal are bonded, and the contact rate between the substrate and the particle layer is 0.01% or more and 20% or less.

[0015] Fig. 1 shows a schematic cross-sectional view illustrating an example of a conductive sheet according to the present embodiment. Fig. 1 shows a schematic cross-sectional view of a conductive sheet 100 in which a particle layer 10 is disposed on a substrate 20. The particle layer 10 shown in Fig. 1 is expressed as a particle layer formed by bonding transition metal particles, and the cross-section may have pores 11.

[0016] In addition, the conductive sheet 100 of this embodiment has pores 11 relatively concentrated at the interface between the substrate 20 and the particle layer 10, and the contact rate between the substrate 20 and the particle layer 10 is small. As a result, the particle layer 10 and the substrate 20 have excellent transferability, so that the particle layer 10 can be easily peeled off from the substrate 20 and transferred to the surface of another medium. Therefore, for example, the conductive sheet 100 of this embodiment can be used as an intermediate transfer medium for the particle layer 10, and only the particle layer 10 can be transferred from the conductive sheet 100 to another substrate. Hereinafter, in this embodiment, the substrate to which the particle layer 10 is transferred is referred to as a transfer substrate, and the substrate to which the particle layer 10 is transferred is referred to as a transfer conductive sheet 200.

[0017] By using the conductive sheet 100 as an intermediate transfer medium for the particle layer 10 in this way, it is possible to prepare a new conductive sheet by transferring the particle layer 10 to a substrate that is difficult to use for plasma treatment or a substrate on which it is difficult to directly form the particle layer 10. For example, a substrate that is difficult to use for plasma treatment is paper, and a substrate on which it is difficult to directly form the particle layer 10 is a building wall. Therefore, by using the conductive sheet 100 of this embodiment, a transfer conductive sheet 200 with a high degree of freedom in selecting a substrate can be obtained.

[0018] In addition, even in cases where the formation range of the particle layer 10 on the conductive sheet 100 is limited due to restrictions such as the size of the plasma reactor, it is possible to form a wider particle layer 10 by combining and transferring the particle layers 10 from multiple conductive sheets 100. Furthermore, the particle layer 10 can be transferred to a curved surface or other surfaces with complex shapes, making it possible to newly create a conductive sheet that is not limited by the plasma reactor. Therefore, by using the conductive sheet 100 of this embodiment, a transfer conductive sheet 200 with a high degree of freedom in shape can be obtained.

[0019] The transfer method is not particularly limited, but may be, for example, a method in which the surface of the conductive sheet 100 on which the particle layer 10 is formed is pressure-bonded to the surface of another substrate, and the substrate 20 is removed while leaving the particle layer 10 on the surface of the other substrate. The configuration of the conductive sheet 100 will be described in detail below.

[0020] 1.1.Particle layer The particulate layer 10 is formed by bonding particles containing a transition metal, and has a relatively large number of pores 11 at the interface with the substrate 20. Note that the particulate layer 10 may have pores at locations other than the interface with the substrate 20.

[0021] In order to express the degree of pores 11 present at the interface with the substrate 20, the contact rate between the substrate 20 and the particulate layer 10 is used in this embodiment. The contact rate between the substrate 20 and the particulate layer 10 is 0.01 to 20%, preferably 0.10 to 15%, and more preferably 0.50 to 10%. When the contact rate is within the above range, transferability tends to be further improved.

[0022] In addition to the contact ratio, the average height of the voids obtained by dividing the area of ​​the voids between the substrate 20 and the particulate layer 10 by the width of the particulate layer 20 may be used as an index in order to express the degree of the voids 11 present at the interface with the substrate 20. The amount of voids between the substrate 20 and the particulate layer 10 can be indicated by this average height. The average height is preferably 30 nm to 200 nm, more preferably 50 nm to 160 nm, and even more preferably 60 nm to 120 nm. When the average height is within the above range, the transferability tends to be further improved.

[0023] The method for adjusting the contact ratio and average height is not particularly limited, but for example, a method of plasma treating the precursor thin film under specific conditions by the manufacturing method described later can be mentioned. During the plasma treatment under the specific conditions, the growth of sintered particles of the transition metal preferentially proceeds on the surface side of the precursor thin film, and the increase in pores proceeds on the interface side between the substrate 20 and the particle layer 10. As a result, pores 11 are easily formed at the interface between the substrate 20 and the particle layer 10, and it is considered that the contact ratio and average height can be achieved. However, the method for adjusting the contact ratio and average height is not limited to the above.

[0024] The average particle size of the particles constituting the particulate layer 10 is preferably 1.0 to 500 nm, more preferably 5.0 to 400 nm, and even more preferably 10 to 300 nm. When the average particle size is within the above range, the sheet resistance tends to be further reduced. The average particle size of the particles constituting the particulate layer 10 can be measured by a transmission electron image of the cross section of the particulate layer 10.

[0025] 1.1.1.Composition The particle layer 10 of the present embodiment contains a transition metal, and may contain other atoms such as oxygen atoms, carbon atoms, phosphorus atoms, etc., as necessary. The transition metal may exist in the form of a metal element or in the form of a metal compound such as an oxide.

[0026] In the particle layer 10, the transition metal may exist in the form of a metal element or a metal compound such as an oxide. The transition metal atoms contained in the particle layer 10 are not particularly limited as long as they are metals of Groups 3 to 11 in the IUPAC periodic table, but preferably contain a metal of Group 11, more preferably contain silver or copper, and even more preferably contain copper. By using such a transition metal, the conductivity of the particle layer 10 tends to be further improved.

[0027] The type of metal compound containing a transition metal is not particularly limited, but examples thereof include sulfides, selenides, tellurides, nitrides, phosphides, oxides, etc. Among these, oxides are preferable because they are less harmful to the human body and relatively easy to produce.

[0028] In addition to the contact rate, the atomic concentration of oxygen in the particle layer may be specified from the viewpoint of expressing the degree of pores 11 present at the interface with the substrate 20. This is because the oxygen concentration in the particle layer tends to decrease due to reduction as particle growth and pore growth progress during plasma treatment. The average atomic concentration of oxygen in the particle layer is preferably 10% or less, more preferably 8% or less, and even more preferably 5% or less. When the atomic concentration of oxygen in the particle layer is within the above range, transferability tends to be further improved.

[0029] The concentration of each atom contained in the particle layer can be determined by analyzing a cross section of the conductive sheet by elemental analysis using energy dispersive X-ray analysis (EDX) attached to a scanning transmission electron microscope (STEM) (STEM-EDX analysis). In this embodiment, the concentration of each atom is expressed as element concentration (atom%) unless otherwise specified.

[0030] In the STEM-EDX analysis, a cross section of a conductive sheet is measured, and for example, when the conductive sheet has a thin metal wire pattern described later, the measurement sample is preferably a thin slice including a cross section of the thin metal wire perpendicular to the extension direction of the thin metal wire. In preparing the measurement sample, if necessary, the conductive sheet may be embedded in a support such as an epoxy resin before forming a thin slice.

[0031] The method for forming the thin section is not particularly limited as long as it is a method that can suppress damage to the cross section of the metal thin wire due to the formation and processing of the cross section, but preferably, a processing method using an ion beam (e.g., BIB (Broad Ion Beam) processing method or FIB (Focused Ion Beam) processing method), precision mechanical polishing, ultramicrotome, etc. can be used.

[0032] Next, the cross section of the formed thin metal wire is observed by STEM to obtain a STEM image of the cross section of the thin metal wire. At the same time, element mapping of the cross section of the thin metal wire is measured by EDX to perform STEM-EDX analysis. Note that, from the viewpoint of preventing oxidation and contamination of the cross section of the thin metal wire, it is preferable to perform the formation of the cross section of the thin metal wire and the STEM-EDX analysis in an inert atmosphere such as argon or in a vacuum.

[0033] 1.1.2.Film Thickness The thickness of the particulate layer 10 is preferably 30 nm to 1000 μm, more preferably 50 nm to 100 μm, even more preferably 100 nm to 10 μm, even more preferably 200 to 1000 nm, and even more preferably 300 to 500 nm. When the thickness is 30 nm or more, the sheet resistance of the particulate layer 10 tends to be lower and the transferability tends to be improved. When the thickness is 1000 μm or less, the transparency tends to be improved when the particulate layer 10 is formed as a pattern having openings, which will be described later. When the thickness is 1000 μm or less, the pattern of the particulate layer 10 tends to be formed more easily.

[0034] The thickness of the particle layer 10 can be determined by cross-sectional STEM evaluation of the particle layer 10 described below. More specifically, the average value of the thicknesses measured at any three positions can be regarded as the thickness of the particle layer 10. Note that the particle layer 10 of the present embodiment may be a thin film having a uniform thickness, or a thin film having unevenness on the surface or having thin portions depending on the position of the particle layer 10.

[0035] Regardless of whether or not there are a relatively large number of pores 11 at the interface between the substrate 20 and the particulate layer 10, the thickness of the particulate layer 10 in this embodiment is defined as the distance from the surface of the substrate 20 to the surface of the particulate layer 10.

[0036] Patterns The particle layer 10 may have a continuous pattern with openings, or a solid pattern without openings. Here, the openings refer to the areas where the conductive sheet is not present, and light can pass through the openings. A continuous pattern refers to a pattern that is confirmed to be connected (contacted) with an optical microscope, and such a pattern may be electrically connected.

[0037] Among these, it is preferable that the particulate layer 10 has a continuous pattern having openings. The pattern of the particulate layer 10 can be designed according to the intended use of the electronic device, and may be a regular pattern or an irregular pattern. Providing openings in this manner is preferable because it can be used to provide, for example, a light-transmitting conductive sheet.

[0038] In addition, it is preferable that the particle layer 10 has a continuous pattern having openings, which can improve the transferability. This is because, in the plasma treatment step described later, the patterned precursor thin film having openings makes it easier to adjust the degree of progress of the plasma reaction compared to a solid film having a relatively large contact area with the substrate, and therefore, it is possible to obtain a conductive sheet with excellent transferability by adjusting the adhesion between the particle layer and the substrate within a predetermined range.

[0039] Here, the mechanism by which a continuous pattern having openings can provide a conductive sheet with excellent transferability is not limited to a specific theory, but is presumed to be as follows: In other words, in the plasma treatment step, the increase in pores between the particle layer and the substrate proceeds more rapidly than in a solid film, forming relatively large pores inside the particle layer, and the temperature at the interface between the substrate and the precursor thin film increases due to the heat of the plasma reaction more than when there are no openings, thereby decreasing the contact rate between the substrate and the particle layer, which contributes to improved transferability.

[0040] When the particulate layer 10 has a continuous pattern with openings, the aperture ratio of the openings is preferably 20 to 99%, more preferably 30 to 97%, and even more preferably 50 to 95%. The larger the aperture ratio, the more the transferability of the particulate layer 10 tends to improve. Also, the smaller the aperture ratio, the smaller the sheet resistance of the particulate layer 10 tends to be.

[0041] The appropriate value of the aperture ratio of the pattern of the particulate layer 10 varies depending on the shape of the pattern of the particulate layer 10. In addition, the aperture ratio of the pattern of the particulate layer 10 can be appropriately combined with the above upper and lower limits depending on the required performance (transmittance and sheet resistance) of the target electronic device.

[0042] The "aperture ratio of the pattern of the particulate layer 10" can be calculated by the following formula for the region on the substrate where the pattern of the particulate layer 10 is formed. The region on the substrate where the pattern of the particulate layer 10 is formed excludes edges and the like where the pattern of the particulate layer 10 is not formed. Opening ratio of the pattern of the particulate layer 10=(1−area occupied by the pattern of the particulate layer 10 / area of ​​the substrate)×100

[0043] When the particulate layer 10 has a continuous pattern with openings, the size of the openings is preferably 0.5 to 1000 μm, more preferably 1 to 500 μm, and even more preferably 10 to 300 μm, in terms of the diameter of the maximum inscribed circle that fills the area of ​​the openings. By having the size of the openings within the above range, transferability tends to be further improved.

[0044] The continuous pattern having openings is not particularly limited, but is preferably, for example, a pattern formed by a plurality of crossing thin lines. In this case, the thin lines correspond to the conductive sheet, and the gaps between the thin lines become the openings.

[0045] Specific examples of the pattern formed by a plurality of thin wires are described below, but the pattern in this embodiment is not limited to the following. In the following, the thin metal wires refer to the particle layer 10 having a thin line shape in a plan view, and the thin metal wire pattern refers to a pattern formed by a plurality of thin metal wires.

[0046] FIG. 2 is a schematic top view showing an example of a pattern 40 of the conductive sheet 100 of this embodiment. FIG. 2 is a top view of the conductive sheet 100 in which the particle layer 10 is disposed on the substrate 20, as viewed from the side on which the particle layer 10 is formed. In FIG. 2, the particle layer 10 is in the form of thin lines, and is shown as a state in which the thin lines cross in a grid shape. Here, the thin line-shaped particle layer 10 is referred to as a thin metal wire 10'. The cross section of FIG. 1 described above shows the cross section of this thin metal wire 10' taken along the line A-A'.

[0047] As shown in Fig. 2, the continuous pattern refers to, for example, a configuration in which a plurality of thin metal wires 10' cross each other to form a continuous layer, thereby allowing electrical current to flow between any two points on the particle layer 10 spreading in the planar direction. Furthermore, having an opening refers to, for example, having discontinuous openings 50 between a plurality of thin metal wires 10'. In this embodiment, the conductive continuous layer and openings formed by the thin metal wires 10' are referred to as a thin metal wire pattern 40.

[0048] Here, the line width W of the fine metal wires 10' constituting the fine metal wire pattern 40 refers to the line width of the fine metal wires 10' when the fine metal wires 10' are projected onto the surface of the substrate 20 from the side of the substrate 20 on which the fine metal wire pattern 40 is disposed. The "projected line width" is defined as the width of the interface between the particle layer 10 and the substrate, for example, as shown in Fig. 1, when the interface is the widest. The pitch P is defined as the sum of the line width W and the distance L between the fine metal wires.

[0049] Specific examples of the above-mentioned fine metal wire pattern include a mesh pattern formed by a plurality of fine metal wires crossing each other in a mesh pattern, and a line pattern formed with a plurality of approximately parallel fine metal wires. The fine metal wire pattern may also be a combination of a mesh pattern and a line pattern. The mesh of the mesh pattern may be a square or rectangle, or a polygon such as a rhombus. The fine metal wires constituting the line pattern may be straight or curved. Furthermore, the fine metal wires constituting the mesh pattern may also be curved.

[0050] Line width The line width W is preferably from 100 nm to 1000 μm, more preferably from 200 nm to 500 μm, even more preferably from 300 nm to 100 μm, still more preferably from 400 nm to 50 μm, and even more preferably from 500 nm to 5.0 μm.

[0051] By making the line width W of the thin metal wire 100 nm or more, the conductivity of the thin metal wire can be sufficiently ensured, and the sheet resistance tends to be further reduced. In addition, the decrease in conductivity due to oxidation or corrosion of the surface of the thin metal wire can be sufficiently suppressed. Furthermore, for the same aperture ratio, the thinner the line width of the thin metal wire, the more the number of thin metal wires can be increased. This makes the electric field distribution of the conductive sheet more uniform, making it possible to fabricate electronic devices with higher resolution. In addition, even if some of the thin metal wires are broken, the other thin metal wires can compensate for the resulting effect.

[0052] On the other hand, by having the line width W of the thin metal wires be 5.0 μm or less, the visibility of the thin metal wires is further reduced, and the transparency of the conductive sheet and the conductive sheet including the same tends to be further improved.

[0053] Aspect Ratio The aspect ratio, which is expressed by the thickness T of the thin metal wire relative to the line width W of the thin metal wire, is preferably 0.05 to 1.00, more preferably 0.08 to 0.90, and further preferably 0.10 to 0.80. When the line width W is constant, the larger the aspect ratio, the more the conductivity tends to improve without decreasing the transmittance. In addition, by keeping the aspect ratio at 1.00 or less, a decrease in transmittance due to an excessively thick film thickness tends to be suppressed.

[0054] Pitch The pitch P is preferably 1.0 to 1000 μm, more preferably 5.0 to 500 μm, even more preferably 50 to 250 μm, and even more preferably 100 to 250 μm. When the pitch P is 1.0 μm or more, the transparency of the conductive sheet and the conductive sheet including the same tends to be improved. When the pitch P is 1000 μm or less, the conductivity tends to be improved. When the shape of the thin metal line pattern is a mesh pattern, the pitch of the thin metal line pattern with a line width of 1 μm is set to 200 μm, so that the aperture ratio can be 99%.

[0055] The line width W, aspect ratio, and pitch P of the thin metal line pattern can be confirmed by observing the cross section of the conductive sheet with an electron microscope or the like. The line width and pitch of the thin metal line pattern can also be observed with a laser microscope or optical microscope. Since the pitch P and the aperture ratio have a relational expression described below, if one is known, the other can be calculated. Methods for adjusting the line width W, aspect ratio, and pitch P of the thin metal line pattern to the desired range include a method of adjusting the grooves of a plate used in the manufacturing method of a conductive sheet described below, and a method of adjusting the average particle size of metal particles in an ink.

[0056] The sheet resistance of a conductive sheet tends to decrease by improving the aspect ratio (height) of the thin metal wires. It can also be adjusted by selecting the type of metal material that makes up the thin metal wires.

[0057] 1.1.7.Visible light transmittance The visible light transmittance of the conductive sheet is preferably 70 to 99%, more preferably 75 to 95%, and further preferably 80 to 90%. The visible light transmittance can be measured by calculating the average transmittance in the visible light range (360 to 830 nm) in accordance with the total light transmittance of JIS K 7361-1:1997. The visible light transmittance of the patterned thin film tends to be improved by reducing the line width of the thin metal line pattern or improving the aperture ratio.

[0058] Sheet Resistance The sheet resistance of the conductive sheet is preferably 0.001 to 20 Ωcm -2 More preferably, it is 0.01 to 17.5 Ωcm -2 and more preferably 0.01 to 15 Ωcm -2 and even more preferably 0.1 to 10 Ωcm -2 The lower the sheet resistance, the more the electrical conductivity tends to improve.

[0059] 1.1.9. Haze The haze of the conductive sheet is preferably 0.01 to 5.00%, more preferably 0.01 to 3.00%, and even more preferably 0.01 to 1.00%. When the haze is 5.00% or less, the clouding of the conductive sheet with respect to visible light tends to be further suppressed. The haze in this specification can be measured in accordance with the haze of JIS K 7136:2000.

[0060] 1.2. Base material The substrate can be appropriately selected according to the application of the conductive sheet, and is not particularly limited. For example, transparent inorganic substrates such as glass, opaque inorganic substrates such as metal plates, transparent or opaque organic substrates such as plastic films can be mentioned. Among these, plastic is preferable from the viewpoint of obtaining a flexible and transparent conductive sheet. In addition, these substrates may have an arbitrary layer on the surface, or may be subjected to an arbitrary surface treatment such as corona treatment.

[0061] The substrate may be in the form of a plate or a film, with the film being preferred from the viewpoint of excellent freedom in shape.

[0062] The plastic is not particularly limited, but examples thereof include transparent organic substrates such as acrylic acid esters, methacrylic acid esters, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polyvinyl chloride, polyethylene, polypropylene, polystyrene, nylon, aromatic polyamide, polyether ether ketone, polysulfone, polyethersulfone, polyimide, and polyetherimide.

[0063] Among these, it is preferable to use polyethylene terephthalate (PET) from the viewpoint of high productivity including the cost reduction effect for manufacturing the conductive sheet. Also, it is preferable to use polyimide from the viewpoint of excellent heat resistance of the conductive sheet. Furthermore, it is preferable to use polyethylene terephthalate and / or polyethylene naphthalate from the viewpoint of advantageous adhesion between the thin film and the substrate.

[0064] The substrate of the thin film used in this embodiment may be made of one material or may be a laminate of two or more materials. In addition, when the transparent substrate is a multilayer body in which two or more materials are laminated, the transparent substrate may be a laminate of organic substrates or inorganic substrates, or a laminate of an organic substrate and an inorganic substrate.

[0065] From the viewpoint of excellent degree of freedom in shape and / or excellent transparency, the thickness of the substrate is preferably 5.0 to 500 μm, more preferably 5.0 to 300 μm, and further preferably 10 to 100 μm.

[0066] 1.2.1.Surface layer The substrate may have multiple layers, and may have a surface layer in the portion in contact with the conductive sheet. By laminating the surface layer on the substrate, it is possible to prevent etching of the substrate in the portion not covered with the thin metal line pattern by plasma or the like when the metal components in the ink are sintered by a baking means such as plasma.

[0067] The components contained in the surface layer are not particularly limited, and examples thereof include silicon compounds (e.g., (poly)silanes, (poly)silazanes, (poly)silthians, (poly)siloxanes, silicon, silicon carbide, silicon oxide, silicon nitride, silicon chloride, silicate salts, zeolites, silicides, etc.), aluminum compounds (e.g., aluminum oxide, etc.), magnesium compounds (e.g., magnesium fluoride), etc. The polysilanes, polysilazanes, polysilthians, and polysiloxanes may have a linear or branched, cyclic, or network-like form. These components may be used alone or in combination of two or more.

[0068] Among these, silicon compounds, aluminum oxide, and magnesium fluoride are preferred, and silicon oxide, silicon nitride, aluminum oxide, and magnesium fluoride are more preferred.By using such components, durability against plasma is improved, and the transferability between the conductive sheet and the substrate is improved.In addition, by using such components, the transparency and durability of the conductive sheet are improved, and the productivity that contributes to the cost reduction effect for manufacturing the conductive sheet is improved.

[0069] The surface layer can be formed by a vapor phase deposition method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD), or by a method of applying and drying a composition in which the components contained in the surface layer are dispersed in a dispersion medium. This composition may contain a dispersant, a surfactant, a binder, etc., as necessary.

[0070] In addition, when the surface layer is included, silicon may be incorporated into the conductive sheet through a plasma reaction. The silicon atom Si contained in the metal fine wire may exist in the form of a silicon atom or a silicon compound, or in the form in which the silicon atom or the silicon compound is bonded to a metal atom (e.g., Si-M, Si-OM, etc.).

[0071] Thickness The thickness of the surface layer is preferably 0.01 to 500 μm, more preferably 0.05 to 300 μm, and further preferably 0.10 to 200 μm. When the thickness of the surface layer is 0.01 μm or more, the transferability between the conductive sheet and the substrate tends to be further improved. In addition, when the thickness of the surface layer is 500 μm or less, the flexibility of the substrate can be ensured.

[0072] Volume resistivity The surface layer preferably has an antistatic function to prevent disconnection of the thin metal wire pattern due to static electricity. From the viewpoint of having the antistatic function, the surface layer preferably contains at least one of a conductive inorganic oxide and a conductive organic compound.

[0073] From the viewpoint of antistatic function, the volume resistivity of the surface layer is preferably 100 to 100,000 Ωcm, preferably 1,000 to 10,000 Ωcm, and preferably 2,000 to 8,000 Ωcm. When the volume resistivity of the surface layer is 100,000 Ωcm or less, the antistatic function tends to be further improved. In addition, when the volume resistivity of the surface layer is 100 Ωcm or more, the electrical conductivity between the metal thin line patterns is further reduced, and the surface layer can be suitably used for applications such as touch panels.

[0074] The volume resistivity can be adjusted by the content of conductive inorganic oxides and conductive organic compounds in the surface layer. For example, if the surface layer contains silicon oxide (volume resistivity 1014 Ω·cm or more), which has high plasma resistance, and an organosilane compound, which is a conductive organic compound, the volume resistivity can be reduced by increasing the content of the organosilane compound. On the other hand, although the volume resistivity increases by increasing the content of silicon oxide, it can be made into a thin film because of its high plasma resistance, and the optical properties are not impaired.

[0075] 1.3.Protective layer The conductive sheet of the present embodiment may have a protective layer (not shown) on the particulate layer 10. The protective layer can be formed so as to sandwich the particulate layer 10 together with the substrate 20.

[0076] The protective layer is not particularly limited as long as it has transparency and can exhibit good adhesion to the conductive sheet or substrate. For example, thermosetting resins such as phenolic resin, thermosetting epoxy resin, thermosetting polyimide, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyurethane, diallyl phthalate resin, and silicone resin; UV-curable resins such as urethane acrylate, acrylic resin acrylate, epoxy acrylate, silicone acrylate, and UV-curable epoxy resin; and commercially available coating agents can be used.

[0077] In this embodiment, the protective layer may be used as a counterpart layer (transfer substrate) to which the particulate layer 10 is transferred.

[0078] 2. Manufacturing method of conductive sheet The method for producing a conductive sheet of the present embodiment includes a film formation step of forming a precursor thin film on a substrate, and a plasma reaction step of reacting the precursor thin film with plasma for 150 to 2000 seconds in the presence of a gas containing molecules containing both hydrogen atoms and oxygen atoms at a partial pressure of 10 to 1000 Pa to form a particle layer, and may optionally include a surface layer formation step of forming a surface layer on the substrate prior to the film formation step.

[0079] 2.1. Surface layer formation process The surface layer forming step is a step of forming the above-mentioned surface layer on the substrate. For example, when a plastic substrate is used, the surface layer can prevent the plastic from being denatured or etched by the plasma reaction.

[0080] A specific example of the surface layer forming method is a method of forming a surface layer by forming a film of a component forming the surface layer on the surface of a transparent substrate using a vapor phase film forming method such as PVD or CVD. Another specific example of the surface layer forming step is a method of forming a surface layer by applying a composition in which the component forming the surface layer is dispersed in a dispersion medium to the surface of a transparent substrate and drying the composition. In addition, the surface layer forming composition may contain a dispersant, a surfactant, a binder, etc., as necessary.

[0081] In the surface layer forming step, it is preferable to use the above-mentioned silicon compound as a component for forming the surface layer.

[0082] 2.2. Film formation process The film forming step is a step of forming a precursor thin film on a substrate.

[0083] 2.2.1. Precursor thin film The precursor thin film contains a transition metal, and is turned into the particle layer of the present embodiment by subjecting it to a plasma reaction process described later. As already described, the conductive sheet having the particle layer obtained by subjecting the precursor thin film to a plasma treatment under predetermined conditions in this manner has excellent transferability.

[0084] Such a precursor thin film can be formed by various methods such as a dry method using a vacuum device, etc., a wet method using an ink, etc. Among these, a method of forming a precursor thin film by printing an ink on a substrate is preferred from the viewpoint of suitability for large-scale production.

[0085] The printing method that can be used is not particularly limited, and examples thereof include letterpress printing, gravure printing, bar coating, spray coating, spin coating, reverse transfer printing, etc. Among these, from the viewpoint of being able to print a relatively precise pattern, formation of the precursor thin film by a plate printing method is preferred.

[0086] Examples of plate-based printing methods include a step of coating the surface of a transfer medium with ink, a step of contacting the ink-coated transfer medium surface with the convex surface of a letterpress plate to transfer a portion of the ink on the transfer medium surface to the convex surface of the letterpress plate, and a step of contacting the transfer medium surface after some of the ink has been transferred with the surface of a substrate to transfer the ink remaining on the transfer medium surface to the surface of the substrate.

[0087] For example, in such a printing method, various shapes of the precursor thin film, such as thickness, width, pitch, etc., and the concentration of each atom contained in the precursor thin film can be controlled by adjusting the printing conditions and ink.

[0088] Ink The ink used in the above printing method contains a metal component and a solvent, and may contain a surfactant, a dispersant, a reducing agent, etc., as necessary.

[0089] 2.2.2.1. Metal particles The metal component may be contained in the ink as metal particles or as a metal complex. Among these, it is preferable that the metal component is contained in the ink as metal particles. As the metal particles, as long as they contain the above-mentioned transition metal atoms, they may be metal oxides such as copper oxide or other metal compounds, or core / shell particles in which the core part is copper and the shell part is copper oxide. Among these, metal oxides such as copper oxide are preferable from the viewpoint of handling.

[0090] The average primary particle size of the metal particles is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. The lower limit of the average primary particle size of the metal particles is not particularly limited, but may be 1 nm or more. From the viewpoint of making the line width W of the obtained thin metal wires thinner, the average primary particle size of the metal particles is preferably 100 nm or less.

[0091] The average secondary particle size of the metal particles is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. From the viewpoint of excellent coatability during thin film formation, it is preferable that each particle is monodispersed and the average secondary particle size is close to the average primary particle size.

[0092] In this embodiment, the "average primary particle size" refers to the particle size of each individual metal particle (so-called primary particle), and is distinguished from the average secondary particle size, which is the particle size of an aggregate (so-called secondary particle) formed by multiple metal particles gathering together.

[0093] Surfactants The surfactant is not particularly limited, but examples thereof include fluorine-based surfactants and silicone-based surfactants. By using such surfactants, the coatability of the ink on the transfer medium (blanket) and the smoothness of the coated ink are improved, and a more uniform coating film tends to be obtained. It is preferable that the surfactant is configured to be capable of dispersing metal components and to be unlikely to remain after baking.

[0094] Solvent The ink solvent is preferably an organic solvent from the viewpoints of excellent storage stability and small light loss. From the above viewpoints, the organic solvent is preferably an alcohol. From the above viewpoints, the number of carbon atoms in the organic solvent is preferably 1 to 7, more preferably 2 or more, more preferably 5 or less, or 4 or less, and most preferably 2.Examples of the solvent include water, propylene glycol monomethyl ether acetate, 3-methoxy-3-methyl-butyl acetate, ethoxyethyl propionate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol tertiary butyl ether, dipropylene glycol monomethyl ether, ethylene glycol butyl ether, ethylene glycol ethyl ether, ethylene glycol methyl ether, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2-pentanediol, 2-methylpentane-2,4-diol, 2,5-hexanediol, 2,4-heptanediol, 2-ethylhexane-1,3-diol, diethylene glycol, hexanediol, octanediol, triethylene glycol, tri-1,2-propylene glycol, glycerol, ethylene glycol monohexyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl acetate, diethylene glycol, monoethyl ether acetate, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, 2-butanol, t-butanol, n-pentanol, i-pentanol, 2-methylbutanol, 2-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, 1-hexanol, 2-hexanol, 2-ethylbutanol, 1-heptanol, 2-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, 2-octanol, n-nonyl Examples of the alcohol include alcohol, 2,6-dimethyl-4-heptanol, n-decanol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, and diacetone alcohol. From the viewpoints of excellent storage stability and low light loss, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, and isomers thereof are more preferable, ethanol, propanol, butanol, and isomers thereof are even more preferable, and ethanol is the most preferable.

[0095] Dispersants The dispersant is not particularly limited, but examples thereof include dispersants that non-covalently bond or interact with metal components, and dispersants that covalently bond with metal components. Examples of functional groups that non-covalently bond or interact with metal components include dispersants having a phosphate group. By using such dispersants, the dispersibility of metal components tends to be further improved.

[0096] 2.3.Plasma reaction process The plasma reaction process is a process in which the precursor thin film obtained as described above is reacted with plasma for 150 to 2000 seconds in the presence of a gas containing molecules containing both hydrogen atoms and oxygen atoms at a partial pressure of 10 to 1000 Pa to obtain a conductive sheet. As a result, the precursor thin film is baked, and the metal particles in the ink are sintered to form a particle layer (conductive thin film), and pore growth progresses between the particle layer and the substrate to form relatively large pores. As a result, a conductive sheet with excellent conductivity and transferability to the substrate can be obtained. In addition, the oxygen concentration in the conductive sheet can be adjusted by including molecules containing both hydrogen atoms and oxygen atoms in the atmosphere during the plasma reaction.

[0097] Plasma can be generated by various methods. Among them, microwave plasma and high frequency plasma are preferable because they are relatively easy to control, and microwave plasma is more preferable from the viewpoint of reducing contamination caused by electrodes for generating plasma in the apparatus.

[0098] The microwave output of the microwave plasma is preferably 0.5 to 10 kW, more preferably 0.5 to 5.0 kW. By using a microwave output of 0.5 kW or more, the transferability of the obtained conductive sheet and substrate can be improved, and the plasma reaction time can be shortened. In addition, by using a microwave output of 10 kW or less, etching or modification of the substrate by the plasma tends to be suppressed.

[0099] The treatment time of the plasma reaction is 150 to 2000 seconds, preferably 160 to 1000 seconds, and more preferably 180 to 500 seconds. By setting the treatment time to 150 seconds or more, a particle layer is formed, and pore growth proceeds between the particle layer and the substrate to form relatively large pores, thereby improving the transferability of the conductive sheet and the substrate. In addition, by setting the treatment time to 2000 seconds or less, the productivity of the conductive sheet tends to be improved.

[0100] The atmosphere of the plasma reaction contains a gas containing molecules containing both hydrogen atoms and oxygen atoms, and may contain a rare gas as necessary. The partial pressure of the gas containing molecules containing both hydrogen atoms and oxygen atoms is preferably 10 to 1000 Pa, more preferably 50 to 500 Pa, and even more preferably 75 to 300 Pa. When the partial pressure of the gas containing molecules containing both hydrogen atoms and oxygen atoms is 10 Pa or more, the increase in pores between the particle layer and the substrate progresses, forming relatively large pores, thereby further improving the transferability of the conductive sheet and the substrate.

[0101] The gas containing molecules containing both hydrogen and oxygen atoms is not particularly limited, but examples thereof include water molecules, organic alcohol molecules, organic ether molecules, organic ester molecules, and organic aldehyde molecules. By using such a gas as the atmosphere of the plasma reaction process, the growth of sintered particles progresses while, for example, reducing copper oxide contained in the ink. In addition, pore growth progresses between the particle layer and the substrate, forming relatively large pores, thereby further improving the transferability of the conductive sheet and the substrate. Furthermore, the conductivity of the conductive sheet to be manufactured tends to be further improved. In particular, it is most preferable to use water molecules as the gas containing molecules containing both hydrogen and oxygen atoms, from the viewpoint of less harm to the human body when leaking and less risk of explosion. The molecules containing both hydrogen and oxygen atoms contained in this gas may be one type or multiple types.

[0102] The rare gas is not particularly limited, but examples thereof include helium, argon, xenon, and krypton. Among these, helium or argon, which have relatively small molecular weights, are preferred, and helium is most preferred, from the viewpoint of reducing sample etching by these plasmas. By using such a rare gas, the plasma reaction can be more easily controlled.

[0103] The above gases may be used in combination, and may further be mixed with other gases.

[0104] The pressure of the plasma reaction may be under increased pressure, reduced pressure, or atmospheric pressure. Among these, reduced pressure is preferable from the viewpoint of lengthening the mean free path of the plasma. Specifically, the pressure is preferably 0.1 to 1000 Pa, more preferably 1.0 to 500 Pa, and further preferably 10 to 300 Pa. When the pressure is 0.1 Pa or more, the mean free path of the plasma tends to be longer. Furthermore, when the pressure is 1000 Pa, it is possible to use a larger amount of reducing gas or rare gas.

[0105] The plasma reaction step in this embodiment is preferably performed on a precursor thin film that constitutes a continuous pattern having openings. As a result, the increase in pores between the particle layer and the substrate progresses, forming relatively large pores, and a conductive sheet with excellent conductivity and transferability to the substrate can be obtained. The mechanism by which this excellent transferability is achieved is not limited to the following, but it is considered that the plasma reaction progresses in the precursor thin film further exposed by the openings, thereby improving the rate of increase in pores, and that the temperature of the interface between the substrate and the precursor thin film increases by the heat of the plasma reaction compared to when there are no openings, thereby reducing the contact rate between the substrate and the particle layer 100 and improving transferability.

[0106] The aperture ratio of the precursor thin film constituting a continuous pattern having openings is preferably 20 to 99%, more preferably 30 to 97%, and further preferably 50 to 95%. The larger the aperture ratio, the more the transferability of the particulate layer 10 tends to improve. Also, the smaller the aperture ratio, the smaller the sheet resistance of the particulate layer 10 tends to decrease.

[0107] The "aperture ratio of the precursor thin film" can be calculated for the region on the substrate where the precursor thin film pattern is formed by the following formula: The region on the substrate where the precursor thin film pattern is formed excludes edges and the like where the precursor thin film pattern is not formed. Opening ratio of precursor thin film pattern = (1 - area occupied by precursor thin film pattern / area of ​​substrate) x 100

[0108] The continuous pattern having openings is not particularly limited, but is preferably, for example, a pattern formed by intersecting a plurality of thin lines. In this case, the thin lines correspond to the precursor thin film, and the gaps between the thin lines become the openings.

[0109] In the same manner as the pattern formed by a plurality of fine metal wires described above, a precursor fine wire pattern can also be formed on the precursor thin film. Note that the precursor fine wire means a precursor thin film in the form of fine wires, and the precursor fine wire pattern means a pattern formed by a plurality of precursor fine wires.

[0110] 2.3.1.Line width The line width of the precursor thin wire is preferably 100 nm to 1000 μm, more preferably 200 nm to 500 μm, even more preferably 300 nm to 100 μm, still more preferably 400 nm to 50 μm, and even more preferably 500 nm to 5.0 μm.

[0111] By making the line width of the precursor thin wire 100 nm or more, the conductivity of the metal thin wire manufactured through the plasma treatment process can be sufficiently ensured, and the sheet resistance tends to be further reduced. In addition, the decrease in conductivity due to oxidation or corrosion of the metal thin wire surface can be sufficiently suppressed. Furthermore, when the aperture ratio is the same, the thinner the line width of the precursor thin wire, the more the number of precursor thin wires can be increased. This makes the electric field distribution of the conductive sheet more uniform, making it possible to manufacture electronic devices with higher resolution.

[0112] On the other hand, by having the line width of the precursor thin wire be 5.0 μm or less, the visibility of the thin metal wire produced through the plasma treatment process tends to be reduced, and the transparency of the conductive thin film and the conductive sheet comprising the same tends to be improved.

[0113] Aspect Ratio The aspect ratio, which is expressed by the thickness T of the precursor thin wire relative to the line width of the precursor thin wire, is preferably 0.05 to 1.00, more preferably 0.08 to 0.90, and further preferably 0.10 to 0.80. When the line width of the precursor thin wire is constant, the larger the aspect ratio, the more likely it is that the conductivity of the metal thin wire produced through the plasma treatment step will be improved without reducing the transmittance. In addition, by having an aspect ratio of 1.00 or less, a reduction in transmittance due to an excessively thick film thickness tends to be suppressed.

[0114] Pitch The pitch P is preferably 1.0 to 1000 μm, more preferably 5.0 to 500 μm, even more preferably 50 to 250 μm, and even more preferably 100 to 250 μm. When the pitch P is 1.0 μm or more, the transparency of the conductive thin film produced through the plasma treatment step and the conductive sheet including the same tends to be improved. Furthermore, when the pitch P is 1000 μm or less, the conductivity tends to be improved. Note that when the shape of the thin metal line pattern is a mesh pattern, the pitch of the thin metal line pattern with a line width of 1 μm is set to 200 μm, thereby making it possible to achieve an aperture ratio of 99%.

[0115] The line width W, aspect ratio, and pitch P of the thin metal line pattern can be confirmed by observing the cross section of the conductive sheet with an electron microscope or the like. The line width and pitch of the thin metal line pattern can also be observed with a laser microscope or optical microscope. Since the pitch P and the aperture ratio have a relational expression described below, if one is known, the other can be calculated. Methods for adjusting the line width W, aspect ratio, and pitch P of the thin metal line pattern to the desired range include a method of adjusting the grooves of a plate used in the manufacturing method of a conductive sheet described below, and a method of adjusting the average particle size of metal particles in an ink.

[0116] 3. Manufacturing method of transfer conductive sheet The method for producing a transfer conductive sheet of the present embodiment includes a transfer step of transferring the particle layer 10 of the conductive sheet 100 obtained as described above to a transfer substrate. As a result, the particle layer 10 is transferred from the conductive sheet 100 to the transfer substrate, so that a transfer conductive sheet 200 can be obtained that has a high degree of freedom in the selection of the substrate and a high degree of freedom in the shape.

[0117] 3.1.Transfer process A schematic diagram showing the method for producing the transfer conductive sheet of this embodiment is shown in Fig. 3. The transfer method in the transfer step is not particularly limited, but may be, for example, a method in which the surface of the conductive sheet 100 on which the particle layer 10 is formed and the surface of the mating transfer substrate 60 are pressed together, and the substrate 20 is removed while leaving the particle layer 10 on the surface of the transfer substrate 60.

[0118] The atmosphere in the transfer step is not limited, and the transfer step can be performed in air or in an inert gas atmosphere, and can be performed under atmospheric pressure or reduced pressure.

[0119] This transfer step can be carried out at various temperatures. From the viewpoint of simplicity, transfer at room temperature is preferred. On the other hand, from the viewpoint that the difference in thermal expansion coefficients of the substrate, the particle layer, and the transfer substrate can be utilized for the transfer, it is preferred to carry out the transfer step under heating.

[0120] The surface free energy of the transfer substrate is preferably 5 mN / m or more and 100 mN / m or less. By using a transfer substrate having the above surface free energy, excellent transferability can be achieved.

[0121] The tensile modulus of the transfer substrate is preferably 0.1 GPa or more and 1000 GPa or less. By using a transfer substrate having the above surface free energy, excellent transferability can be achieved.

[0122] 4. Touch Panel The touch panel of the present embodiment is not particularly limited as long as it includes the conductive sheet. For example, in a capacitive touch panel, two conductive sheets are present on the front and back sides of an insulator, and the two conductive sheets face each other so that, for example, the line patterns of thin metal wires cross. The conductive sheets are connected to an extraction electrode, and the extraction electrode connects the thin metal wires to a controller (such as a CPU) for switching the current supply to the thin metal wires.

[0123] The touch panel of the present embodiment is not limited to a capacitive type, and may be a resistive film type, a projected capacitive type, a surface capacitive type, or the like.

[0124] 5. Display The display of the present embodiment is not particularly limited as long as it includes the conductive sheet. For example, an organic electroluminescence (EL) display has a structure in which an organic EL film is sandwiched between electrodes, and the conductive sheet can be used as one of the electrodes. Also, a liquid crystal display has a structure in which a liquid crystal layer is sandwiched between electrodes, and the conductive sheet can be used as one of the electrodes.

[0125] 6. Heater The heater of the present embodiment is not particularly limited as long as it includes the conductive sheet. For example, an electric heater has an electric heating part that generates Joule heat when electricity is supplied thereto, and a power supply device that supplies power to the electric heating part, and a conductive sheet can be used as the electric heating part. If the conductive sheet is made transparent, it becomes a transparent heater, and if the conductive sheet is designed to have a high resistance, it becomes a heater with a high heat generation amount.

[0126] For example, the use of the transparent heater is not particularly limited, but examples thereof include anti-fogging or anti-freezing heaters for LED lighting fixtures used in automobile headlamps, taillamps, etc., and anti-fogging or anti-freezing heaters for outdoor LED lighting fixtures used in street lamps, etc.

[0127] 7.Electromagnetic Shielding The electromagnetic wave shield of the present embodiment is not particularly limited as long as it includes the conductive sheet. For example, the electromagnetic wave shield includes a shielding material that reflects or absorbs incident electromagnetic waves, and the conductive sheet can be used as the shielding material.

[0128] 8. Antenna The antenna of the present embodiment is not particularly limited as long as it is equipped with the conductive sheet. For example, an RF tag has a semiconductor element and an antenna connected thereto, which enables transmission and reception of a specific frequency, and the conductive sheet can be used as the antenna. If the conductive sheet is made transparent, it becomes a transparent antenna. EXAMPLES

[0129] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0130] (Thin film morphology evaluation) The obtained substrate with the conductive thin film was cut with a razor, embedded in a vapor-deposited carbon layer, and thin slices with a thickness of about 100 nm were formed with a focused ion beam. The obtained thin slices were used as measurement samples, and irradiated with an electron beam under the following conditions to prepare evaluation samples, and STEM-EDX analysis was performed. The film thickness of the particle layer, the fact that the particle layer was a layer formed by sintering metal particles together, and the contact rate were determined from this cross-sectional TEM image. The oxygen concentration of the thin film was measured by STEM-EDX analysis. Furthermore, the pattern shape, line width, pitch, etc. of the particle layer were evaluated with a laser microscope (OLYMPUS, OLS-4500).

[0131] [STEM-EDX equipment conditions] STEM: Hitachi High-Technologies Corporation, scanning transmission electron microscope HD-2300A EDX: EDAX Energy Dispersive X-ray Analysis System Octane T Plus (Software: GENESIS) Acceleration voltage: 200kV Measurement magnification: 100,000x Mapping elements: Cu, O, P, Si, C

[0132] (Transferability) The transferability of the particle layer to the substrate was evaluated by the following transfer test to a polytetrafluoroethylene (PTFE) sheet. A PTFE sheet was brought into contact with the particle layer of the conductive sheet produced in the examples or comparative examples, and a 2N (Newton) roller was rolled back and forth twice from above. Thereafter, the PTFE sheet (surface free energy: 22 mN / m, tensile modulus: 0.5 GPa) was peeled off from the PET sheet at a speed of 100 mm / min, and a transfer test of the particle layer (thin metal wires) to the PTFE sheet was carried out. The surface of the PTFE sheet and the substrate surface after peeling were visually observed to confirm whether the thin metal wires were transferred or not. Transferability: No change was observed on the substrate surface before the test. Moreover, the transfer of the particle layer to the Teflon sheet was observed. Transferability ×: There is no change in the substrate surface from before the test. Furthermore, no migration onto the Teflon sheet was observed.

[0133] <Example 1> (Preparation of Transparent Substrate) A surface layer-forming composition containing silicon oxide nanoparticles and a conductive organosilane compound was applied onto a transparent substrate made of polyethylene terephthalate (PET), and then dried to form a surface layer containing silicon oxide with an antistatic function, a thickness of 150 nm, and a volume resistivity of 5000 Ωcm, to obtain a substrate. This substrate has a surface layer laminated on the substrate, PET.

[0134] (Ink Preparation) 20 parts by mass of cuprous oxide nanoparticles with a primary particle size of 21 nm, 4 parts by mass of a dispersant (manufactured by Big Chemie, product name: Disperbyk-145), 1 part by mass of a surfactant (manufactured by Seimi Chemical, product name: S-611), and 75 parts by mass of ethanol were mixed to prepare an ink containing 20% ​​by mass of cuprous oxide nanoparticles.

[0135] (Precursor thin film formation process) First, ink was applied to the surface of the transfer medium, and then the ink-coated surface of the transfer medium was brought into contact with a plate having grooves of a thin metal line pattern, and a portion of the ink on the surface of the transfer medium was transferred to the convex surface of the plate. After that, the remaining ink-coated surface of the transfer medium was brought into contact with a substrate, and the ink in the form of a thin metal line pattern was transferred onto the substrate. This process produced a precursor thin film. The thickness of this precursor thin film was 360 nm, the line width was 3 μm, and the pitch was 60 μm. Table 1 shows these results.

[0136] (Plasma reaction process) The precursor thin film obtained as described above was subjected to a plasma reaction. Specifically, plasma was generated by microwaves generated at an output of 0.9 kW in an atmosphere under reduced pressure with a partial pressure of water molecules of 100 Pa, and the plasma was reacted with the precursor thin film for 180 seconds to obtain a conductive sheet.

[0137] Various evaluations were carried out on the conductive sheet of Example 1. The results are shown in Table 1.

[0138] <Example 2> Except for changing the reaction time of the plasma reaction step to 300 seconds, the same operation as in Example 1 was carried out. The results are shown in Table 1.

[0139] <Comparative Example 1> Except for changing the reaction time of the plasma reaction step to 60 seconds, the same operation as in Example 1 was carried out. The results are shown in Table 1.

[0140] [Table 1] [Industrial Applicability]

[0141] 10...particle layer, 10'...thin metal wire, 11...hole, 12...particle, 20...substrate, 40...thin metal wire pattern, 50...opening, 60...transfer substrate, 100...conductive sheet, 200...conductive transfer sheet

Claims

1. A substrate; a particle layer having transition metal-containing particles bonded thereto, the particle layer being laminated on the substrate; The contact rate between the substrate and the particle layer is 0.01% or more and 20% or less. Conductive sheet.

2. The particle layer forms a continuous pattern having openings. The conductive sheet according to claim 1 .

3. The opening ratio of the particle layer to the substrate is 20% or more and 99% or less. The conductive sheet according to claim 2 .

4. The diameter of the largest inscribed circle filling the opening is 0.5 μm or more and 1000 μm or less. The conductive sheet according to claim 2 or 3.

5. The pattern is a pattern formed by intersecting a plurality of thin lines. The conductive sheet according to any one of claims 2 to 4.

6. The line width of the thin line is 100 nm or more and 1000 μm or less. The conductive sheet according to claim 5 .

7. The pitch of the thin lines is 1.0 μm or more and 1000 μm or less. The conductive sheet according to claim 5 or 6.

8. The thickness of the particle layer is 30 nm or more and 1000 μm or less. The conductive sheet according to any one of claims 1 to 7.

9. the average height of the voids, which is obtained by dividing the area of ​​the voids between the substrate and the particle layer by the width of the particle layer, is 30 nm to 200 nm; The conductive sheet according to any one of claims 1 to 8.

10. The average atomic concentration of oxygen in the particle layer is 10% or less. The conductive sheet according to any one of claims 1 to 9.

11. The substrate has a plurality of layers. The conductive sheet according to any one of claims 1 to 10.

12. The substrate has a surface layer containing a silicon compound. The conductive sheet according to any one of claims 1 to 11.

13. The substrate is a plastic. The conductive sheet according to any one of claims 1 to 12.

14. The plastic is polyethylene terephthalate. The conductive sheet according to claim 13.

15. The transition metal comprises a metal of Group 11 of the IUPAC Periodic Table; The conductive sheet according to any one of claims 1 to 14.

16. The transition metal comprises copper. The conductive sheet according to claim 15.

17. The average particle size of the particles contained in the particle layer is 1.0 nm or more and 500 nm or less. The conductive sheet according to any one of claims 1 to 16.

18. The visible light transmittance is 70% or more and 99% or less. The conductive sheet according to any one of claims 1 to 17.

19. Sheet resistance is 0.001 Ω cm -2 20Ωcm or more -2 Below is the The conductive sheet according to any one of claims 1 to 18.

20. The conductive sheet according to any one of claims 1 to 19 is provided. Touch panel.

21. The conductive sheet according to any one of claims 1 to 19 is provided. display.

22. The conductive sheet according to any one of claims 1 to 19 is provided. Heater.

23. The conductive sheet according to any one of claims 1 to 19 is provided. Electromagnetic wave shielding.

24. The conductive sheet according to any one of claims 1 to 19 is provided. antenna.

25. a film forming step of forming a precursor thin film on a substrate; a plasma treatment step of reacting the precursor thin film with plasma in the presence of a gas containing molecules containing both hydrogen atoms and oxygen atoms at a partial pressure of 10 Pa to 1000 Pa for 150 seconds to 2000 seconds to form a particle layer, A method for manufacturing a conductive sheet.

26. The molecule containing both a hydrogen atom and an oxygen atom is a water molecule. A method for producing the conductive sheet according to claim 25.

27. The precursor thin film forms a continuous pattern having openings. A method for producing the conductive sheet according to claim 25 or 26.

28. The aperture ratio of the precursor thin film to the substrate is 20% or more and 99% or less. A method for producing a conductive sheet according to any one of claims 25 to 27.

29. In the plasma treatment step, microwave plasma is used. A method for producing a conductive sheet according to any one of claims 25 to 28.

30. A transfer step of transferring the particle layer of the conductive sheet according to any one of claims 1 to 19 to a transfer substrate, A method for producing a transfer conductive sheet.

31. The surface free energy of the transfer substrate is 5 mN / m or more and 100 mN / m or less. The method for producing a transfer conductive sheet according to claim 30.

32. The tensile modulus of the transfer substrate is 0.1 GPa or more and 1000 GPa or less. A method for producing a transfer conductive sheet according to claim 30 or 31.

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