JP2014035849A - Method for manufacturing electroconductive laminate, electroconductive laminate, and display object using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an electroconductive laminate simultaneously satisfying a high electroconductivity and a high transparency (low haze and high transmissivity).SOLUTION: In the provided method for manufacturing an electroconductive laminate, an electroconductive layer 2 is configured on at least one side of a base material 1 based on the following steps (A) through (D): (A) a step of forming a coating film by coating, on the base material, a first coating liquid in which a linear metallic structure is dispersed within an eventual coating film thickness range of 10-100 μm; (B) a step of realizing a state where the linear metallic structure is mounted on the base material by removing an aqueous dispersive medium from the coating film of the first coating liquid formed on the base material at the step (A); (C) a step of coating, on the linear metallic structure mounted on the base material at the step (B), a second coating liquid provided by dissolving, into a solvent, a material scheduled to become a matrix 3; and (D) a step of forming, on the base material, an electroconductive layer including the linear metallic structure within the matrix by removing the dispersive medium from the second coating liquid coated on the linear metallic structure at the step (C).

Description

  The present invention relates to a production method for producing a conductive laminate in which a conductive layer having a linear metal structure as a conductive component in a matrix is disposed on at least one surface of a substrate, and to the conductive laminate. Furthermore, the present invention relates to a display body using the conductive laminate.

  In recent years, conductive members using tin-doped indium oxide (ITO) or metal particles have been used for display-related matters such as touch panels, liquid crystal displays, organic electroluminescence, electronic paper, and solar cell modules. As an alternative material for these conductive members, there is a conductive member using a linear metal structure, and there is a coating liquid in which the linear metal structure is dispersed in an aqueous dispersion medium.

  Water has a very high heat of vaporization compared with common organic solvents, and the solvent may not be sufficiently removed when the solvent is removed by drying. In this case, brushing may occur when forming the matrix on the linear metal structure as necessary. Here, brushing is a phenomenon in which bubbles derived from water are formed in the coating film and in the surface portion during and immediately after application of the coating liquid, and the surface becomes white and loses its gloss, resulting in a significant increase in haze value. It means that the surface glossiness is lowered. As a technique for suppressing this brushing, techniques for controlling the humidity of the dry atmosphere have been proposed (Patent Documents 1, 2, and 3). In addition, methods for suppressing brushing by changing the composition of the matrix coating liquid have also been proposed (Patent Documents 4 and 5).

JP 2007-256759 A JP 2005-292291 A JP-A-10-236008 JP 2009-157020 A JP 2011-225797 A

  In Patent Documents 1, 2, and 3, application and drying are performed under low humidity in order to suppress brushing. However, in these documents, the coating liquid forming each layer uses an organic solvent as a dispersion medium, and the amount of water originally contained in the paint is small. Therefore, brushing is suppressed by controlling the humidity of the coating and drying environment, but this is not sufficient when the lower layer dispersion medium is water when forming the matrix, and the drying conditions of the lower layer water dispersion medium are insufficient. It is also necessary to consider. In Patent Documents 4 and 5, brushing is suppressed by optimizing the solvent and solute composition of the matrix paint. However, in this method as well, when the lower layer dispersion medium in forming the matrix is water as described above, this is not sufficient, and it is necessary to consider the drying conditions of the lower layer water dispersion medium.

In order to solve this problem, the present invention employs the following configuration. That is,
(1) A method for producing a conductive laminate in which a conductive layer is provided on at least one of the substrates by the following steps (A) to (D), wherein (B1), (B2) and (B3) The manufacturing method of the electrically conductive laminated body characterized by applying the heating conditions of.
(A) Step (B) (A) step of forming a coating film by applying the first coating liquid in which the linear metal structure is dispersed in water so that the coating film thickness is in the range of 10 to 100 μm. Removing the water dispersion medium from the coating film of the first coating liquid formed on the base material in step (C) and placing the linear metal structure on the base material. The step (D) and the step (C) of applying the second coating liquid dissolved in the step (B) on the linear metal structure placed on the substrate in the step (B) were applied onto the linear metal structure. The step of removing the solvent from the second coating liquid and forming a conductive layer containing the linear metal structure in the matrix on the substrate (B) includes the following (B1), (B2) and The heating condition (B3) is included.
(B1) There is a heating stage of heating at 25 ° C. or more and less than 40 ° C. for 30 to 130 seconds (B2) The total heating time is 70 seconds or more (B3) Under an atmosphere with an absolute humidity of 15 g / m ³ or less Heating (2) The method for producing a conductive laminate according to (1), wherein the linear metal structure is a metal fiber or a carbon nanotube.
(3) The manufacturing method of the electrically conductive laminated body as described in said (2) whose said metal fiber is silver nanowire.

Furthermore, this invention provides the following display body, a touch panel using the same, and electronic paper.
(4) The display body using the electrically conductive laminated body obtained by the manufacturing method in any one of said (1)-(3).
(5) A touch panel using a conductive laminate obtained by the manufacturing method according to any one of (1) to (3).
(6) Electronic paper using the conductive laminate obtained by the production method according to any one of (1) to (3).

  According to the present invention, when a conductive laminate is formed using a paint in which a linear metal structure is dispersed in an aqueous dispersion medium, a matrix layer using an organic solvent as a dispersion medium is further provided on the conductive laminate. In addition, it is possible to provide a conductive laminate that is less susceptible to brushing.

It is sectional drawing which shows the outline of the electrically conductive laminated body of this invention. It is a schematic diagram which shows the outline of the form of the linear metal structure used in this invention.

[Method for producing conductive laminate]
The method for producing a conductive laminate of the present invention is a method for producing a conductive laminate in which a conductive layer is provided on at least one of the substrates by the following steps (A) to (D), wherein (B1) ), (B2), and (B3).
(A) Step (B) (A) step of forming a coating film by applying the first coating liquid in which the linear metal structure is dispersed in water so that the coating film thickness is in the range of 10 to 100 μm. Removing the water dispersion medium from the coating film of the first coating liquid formed on the base material in step (C) and placing the linear metal structure on the base material. The step (D) and the step (C) of applying the second coating liquid dissolved in the step (B) on the linear metal structure placed on the substrate in the step (B) were applied onto the linear metal structure. The step of removing the solvent from the coating film of the second coating solution and forming a conductive layer containing the linear metal structure in the matrix on the substrate (B) includes the following (B1), ( The heating conditions of B2) and (B3) are included.
(B1) There is a heating stage of heating at 25 ° C. or more and less than 40 ° C. for 30 to 130 seconds (B2) The total heating time is 70 seconds or more (B3) Under an atmosphere with an absolute humidity of 15 g / m ³ or less To heat.

  In the method for producing a conductive laminate of the present invention, the aqueous dispersion medium of the coating film of the first coating liquid containing the linear metal structure is removed by applying conditions satisfying the above when forming the conductive layer. In the step (B) where the linear metal structure is placed on the substrate, brushing occurs by applying specific conditions as the heating conditions (B1), (B2) and (B3). It is possible to provide a conductive laminate that is difficult to conduct.

Specifically, (A) the first coating liquid in which the linear metal structure is dispersed in water is applied to the substrate so that the thickness of the coating film is in the range of 10 to 100 μm, and a coating film is formed. (B1) There is a heating stage in which heating is performed at 25 ° C. or more and less than 40 ° C. for 30 to 130 seconds. (B2) The total heating time is 70 seconds or more. (B3) The atmosphere has an absolute humidity of 15 g / m ³ or less. Thus, the aqueous dispersion medium contained in the coating film is sufficiently removed. Each heating may be performed in one heating chamber or may be performed using a plurality of heating chambers.

[Conductive component]
The conductive component of the conductive layer in the production method of the present invention is a linear metal structure. A linear metal structure is known as a so-called metal nanowire, and is a linear metal containing at least a metal component such as a metal, an alloy, a metal oxide, a metal nitride, or a metal hydroxide on the surface. It has a form.

<Material>
Examples of the metal constituting the metal component include IIA, IIIA, IVA, VA, VIA, VIIA, VIII, IB, IIB, IIIB, and IVB in the short periodic table of elements. Examples include elements belonging to the genus or genus VB. Specifically, gold, platinum, silver, nickel, copper, aluminum, gallium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, manganese, antimony, palladium, bismuth, technetium, rhenium, iron, osmium, cobalt Zinc, scandium, boron, gallium, indium, silicon, germanium, tellurium, tin, magnesium and the like.

Examples of the alloy include alloys containing the metal (stainless steel, brass, etc.). Examples of the metal oxide include InO ₂ , SnO ₂ , ZnO, and the like, and these metal oxide composites (InO ₂ Sn, SnO ₂ —Sb ₂ O ₄ , SnO ₂ —V ₂ O ₅ , TiO _2). (Sn / Sb) O ₂ , SiO ₂ (Sn / Sb) O ₂ , K ₂ O—nTiO ₂ — (Sn / Sb) O ₂ , K ₂ O—nTiO ₂ —C, etc.).

  Furthermore, the linear metal structure used in the present invention includes a linear structure made of an organic compound or a non-metallic material and having the metal or metal oxide coated or deposited on the surface thereof.

  These linear metal structures can be obtained, for example, by the production methods disclosed in JP-T-2009-505358, JP-A-2009-146747, and JP-A-2009-70660.

  In addition, the linear metal structure can be applied alone or in combination, and other micro-to-nano-sized conductive materials may be added as required. It is not limited.

  As such a linear metal structure, metal fibers or carbon nanotubes are preferable from the viewpoints of processability to a linear structure, dispersibility in a coating liquid, and dispersion stability. Examples of the material used as the metal fiber include copper, gold, silver, iron, nickel, cobalt, lead, etc. Among them, a linear metal structure using gold or silver is preferable in terms of conductivity and reliability. However, silver nanowires are more preferable in terms of the equipment and cost required for the synthesis of the linear metal structure and the stable synthesis of the length and diameter of the linear metal structure.

<Form>
The average diameter of the linear metal structure and the length of the linear metal structure (sometimes referred to as the length of the long axis of the linear metal structure) may vary depending on the type of the linear metal structure. However, the average diameter is preferably 1 to 100 nm, and the length of the linear metal structure is such that the aspect ratio (length of the linear metal structure / average diameter) is greater than 10 with respect to the average diameter. 1-100 micrometers (0.1 mm) is preferable.

  In the present invention, if the average diameter is reduced, the light diffusion on the surface of the linear metal structure can be relatively lowered, and the haze value can be reduced, and if the average diameter is increased in the above range, The conductivity is improved and a low surface resistance value can be obtained. From this viewpoint, the average diameter is more preferably 10 to 70 nm, and further preferably 40 to 60 nm. In addition, the average diameter of a linear structure is calculated | required with the following method.

  First, embed the sample in the vicinity of the part to be observed with ice, freeze and fix it, and then use a rotary microtome manufactured by Japan Microtome Laboratories Co., Ltd. Cut in any direction. Next, the obtained conductive region of the cross section of the laminate was imaged using an electric field emission scanning electron microscope (JSM-6700-F manufactured by JEOL Ltd.) at an acceleration voltage of 3.0 kV and an observation magnification of 10,000 to 100,000. Adjust the contrast appropriately and observe. For one specimen, images including a cross section of a linear structure obtained from different parts are prepared for 10 visual fields. Next, the diameters of the cross-sections of all the linear structures in the 10 fields of view are obtained, and the total average value is taken as the average diameter. In this measurement, a magnification that can secure 3 significant digits is selected, and the value is calculated by rounding off the 4th digit.

  In the conductive laminate obtained by the production method of the present invention, the linear metal structure exists in a network structure in the matrix of the conductive layer. The network structure means having a dispersion structure in which the average number of contacts with another linear metal structure exceeds at least 1 when viewed with respect to individual linear metal structures in the conductive layer.

  At this time, the contact may be formed by any part of the linear metal structure, the end parts of the linear metal structure are in contact with each other, or the terminal and the part other than the end of the linear metal structure are in contact. Or portions other than the ends of the linear metal structure may be in contact with each other. Here, the contact may mean that the contact is joined or simply in contact. In the conductive laminated body of the present invention, if a linear metal structure having a network structure is present, the conductive laminate does not contribute to formation of a network among the linear metal structures in the conductive layer (that is, the contact is 0). In this case, a part of the linear metal structure that exists independently of the network may exist.

  By forming a network structure using a linear metal structure, it is superior in flexibility to a conductive film made of a metal crystal like ITO, so that during the post-processing of the conductive film It is possible to suppress the defect rate, and it is easy to mount on a three-dimensional display or a flexible display.

  Furthermore, the opening area on the network structure can be increased by forming the network structure using the linear metal structure having the average diameter and the aspect ratio described above, in particular, silver nanowires having good conductivity efficiency. And a highly transparent conductive laminate can be obtained.

  These network structures include a scanning transmission electron microscope (Hitachi Scanning Electron Microscope HD-2700 manufactured by Hitachi High-Technologies Corporation), a field emission scanning electron microscope (JSM-6700-F manufactured by JEOL Ltd.), or color. It can be observed using a 3D laser microscope (VK-9710 manufactured by Keyence Corporation).

  If the amount of the linear metal structure in the conductive layer is below a certain level, there may be a region where the linear metal structure does not exist in the surface. In FIG. 4, the linear metal structure has a network structure, so that conductivity can be exhibited between any two points.

  Thus, a conductive layer having excellent conductivity can be obtained by having a conductive component having a network structure composed of a highly conductive linear metal structure.

[Step (A)]
In the present invention, the first coating liquid in which the linear metal structure is dispersed in a dispersion medium is applied onto the substrate to form a coating film, depending on the type of material constituting the linear metal structure and the matrix. It is only necessary to select the most suitable method, such as casting, spin coating, dip coating, bar coating, spraying, blade coating, slit die coating, gravure coating, reverse coating, screen printing, mold coating, printing transfer, and wet coating methods such as inkjet. A general method can be mentioned. Of these, a slit die coat that can form a coating film uniformly and hardly damages the substrate, or a wet coating method using a micro gravure that can form a coating film uniformly and with high productivity is preferable.

  The film thickness of the coating film including the linear metal structure formed on the substrate can be applied with a film thickness suitable for the various coating methods described above, and is preferably 10 to 100 μm when slit die coating is used. More preferably, the thickness is 15 to 60 μm. If the thickness of the coating film exceeds 100 μm, the coating film flows during conveyance of the substrate, and the uniformity of the conductive performance may be impaired. If it is less than 10 μm, it becomes difficult to stably form the coating film. There is a case.

[Step (B)]
As a step before forming the conductive layer, a step of removing the dispersion medium from the coating film containing the linear metal structure applied on the substrate and placing the linear metal structure on the substrate Is the step (B).

Step (B) includes the following heating conditions (B1), (B2), and (B3).
(B1) There is a heating stage of heating at 25 ° C. or more and less than 40 ° C. for 30 to 130 seconds (B2) The total heating time is 70 seconds or more (B3) Under an atmosphere with an absolute humidity of 15 g / m ³ or less To heat.

  Prior to explaining the meaning of applying these heating steps, a general explanation (mechanism / heating method) of removing the dispersion medium from the coating film is given first, and then the relationship with the conditions of each heating step. Will be described.

In general, the mechanism for removing the dispersion medium from the coating film can be classified into the following three stages.
(I) Most of the added heat is not used for removing the dispersion medium from the coating film, but is consumed mainly for the temperature rise to the equilibrium temperature in the stage (II).
(II) "Definite-rate dispersion medium removal stage" where most of the amount of heat added to the removal of the dispersion medium (heat of vaporization) is consumed and the material temperature reaches the equilibrium temperature
(III) A “decreasing dispersion medium removal stage” in which the temperature of the coating film increases toward the ambient temperature while the dispersion medium removal speed decreases.

  The amount of heat applied is mainly consumed for removing the dispersion medium in the coating film in the constant-rate dispersion medium removal stage, and in the reduction-rate dispersion medium removal stage, a trace amount of dispersion medium remaining in the coating film is removed. Although the removal of the dispersion medium is almost completed at the constant rate dispersion medium removal stage, if the dispersion medium is water, brushing will occur in the process after using the dispersion medium as an organic solvent unless the removal of the solvent is performed more reliably. There is. In the present invention, after forming a layer using a coating liquid using an aqueous dispersion medium, and further providing a matrix layer using an organic solvent as a dispersion medium on the layer, the moisture content of the coating film using the aqueous dispersion medium It is necessary to remove the powder sufficiently.

  Next, the following methods are generally known as typical heating methods for removing the dispersion medium from the coating film. One is a method in which hot air is blown using a nozzle or the like and heated by convection heat transfer, and the other is a method in which heat is applied by radiant heat using an infrared heater or the like.

  The method of heating by convection heat transfer not only raises the temperature of the coating film by the heated air flow supplied using a nozzle etc., but also actively circulates and removes the saturated dispersion medium vapor layer in the vicinity of the coating film, By using in combination with exhaust, the saturated dispersion medium vapor layer can be efficiently removed. On the other hand, the method of heating by radiant heat is more suitable to the method of heating by convective heat transfer at the constant rate dispersion medium removal stage because the saturated dispersion medium vapor layer in the vicinity of the coating film may not be circulated efficiently. By using this, the removal of the dispersion medium can proceed without reducing the dispersion medium removal rate.

  The temperature and humidity of the heating conditions are values obtained by measuring the ambient temperature at a position where the horizontal position is the center of the heating chamber and the vertical position is 10 mm above the substrate in all the heating chambers included in the heating stage. It shall be said. The heating time can be adjusted from input to removal in the case of batch processing, and in the case of continuous processing, by the line speed and the length of the heating chamber in the running direction in the heating stage.

  In the manufacturing method of the conductive laminate of the present invention, after forming the conductive laminate using a paint in which a linear metal structure is dispersed in an aqueous dispersion medium, further considering Description will be made including the reason why it is possible to provide a conductive laminate that hardly causes brushing when a matrix layer using an organic solvent as a dispersion medium is provided on the layer.

  Among the stages (I) to (III), the stage (hereinafter referred to as the heating first stage) of (I) “preheating stage” and (II) “constant dispersion medium removal stage” in the initial stage or in the middle Since the viscosity of the coating film is the lowest because the aqueous dispersion medium content in the coating film is the highest, the uniformly coated coating film is washed away by the air current when the wind speed for removing the aqueous dispersion medium is strong. There is a possibility that the uniformity of the coating thickness may be impaired. Therefore, it is preferable to set a low wind speed in the first heating stage.

  Specifically, it is preferable to remove the dispersion medium under a condition where the air velocity is 6 to 15 m / sec until 30% by mass of the aqueous dispersion medium contained in the coating film is removed.

  As the removal of the aqueous dispersion medium proceeds, the viscosity of the coating film increases, so that it is possible to increase the wind speed. Specifically, in the stage until 30 to 60% by mass is removed, the wind speed of the air current is 6 to 25 m. It is preferable to remove the dispersion medium under the conditions of / min.

  Moreover, it is preferable that heating temperature is 25 degreeC or more and less than 40 degreeC. If the temperature is less than 25 ° C., removal of the dispersion medium may be insufficient, and brushing is likely to occur in the step (C). Furthermore, since heating tends to occur when heated at 40 ° C. or higher in a state where the aqueous dispersion medium content is high, the heating temperature in the first heating stage is preferably less than 40 ° C.

  Although absolute humidity changes with heating time, the thickness of a coating film, and a wind speed, it is preferable that it is 30 to 130 seconds. If it is less than 30 seconds, the removal of the aqueous dispersion medium of the coating film is small, and the coating film is washed away by the wind speed, and the uniformity of the coating film thickness may be impaired or unevenness may occur.

  Subsequently, in the remaining (II) “fixed rate dispersion medium removal stage” (hereinafter referred to as the heating second stage), the dispersion medium in the coating film is reduced by removing the heated water dispersion medium up to the first heating stage. Therefore, since the temperature at which the viscosity becomes the same as that in the first heating stage is increased, relatively high temperature conditions can be taken compared to the first heating first stage, and the processing time is shortened accordingly. It can be time.

  That is, the step of removing the aqueous dispersion medium remaining after the treatment in the first heating step can be taken by heating at 40 ° C. or higher and 90 ° C. or lower for 20 to 80 seconds. Moreover, since the possibility that the uniformity of the coating film thickness due to the air current is impaired due to the increase in the viscosity is reduced, the wind speed can be set to 6 to 30 m / min in order to increase the efficiency of removing the aqueous dispersion medium. .

  Under these temperature and wind speed environments, the removal of the aqueous dispersion medium from the coating film can be further promoted. In addition, if there is a steep temperature difference at the boundary between the first heating stage and the second heating stage, there is a risk of causing unevenness in removing the aqueous dispersion medium from the coating film. Therefore, if the temperature difference between the final heating chamber temperature in the first heating stage and the first heating chamber in the second heating stage, and the second heating stage is composed of a plurality of heating chambers, heating in the second heating stage is performed. The temperature difference between the chambers is preferably 30 ° C. or less. In addition, since a plurality of heating chambers having a temperature difference of 30 ° C. or less are used as the second heating stage, the maximum temperature can be set higher and the removal efficiency of the dispersion medium can be improved. preferable.

  In the “decreasing dispersion medium removing stage” (hereinafter referred to as the heating third stage) after the second heating stage, the heating temperature can be increased to 180 ° C. in order to further remove the dispersion medium. In this case, if the removal of the dispersion medium is insufficient, brushing is likely to occur during matrix formation, so the temperature, heating time, and temperature gradient should be adjusted according to the dispersion medium removal state of the coating film and the characteristics of the substrate. In this case, the heating time is preferably 20 seconds or more, and the wind speed of the airflow is preferably 20 to 30 m / second.

  In addition, depending on the type of substrate, when the heating temperature is high, deformation, melting, or modification of the substrate surface that cannot be visually confirmed may occur. For example, when polyethylene terephthalate (PET) is used for the base material, the base material component may be eluted on the surface even at a temperature at which no deformation or melting occurs, and the flatness of the base material surface is impaired. Therefore, when only the removal of the dispersion medium from the coating film is intended, it is more preferable to heat at over 90 ° C. and 120 ° C. or less.

  If heat shrinkage of the substrate due to heating is expected in subsequent processing steps, etc., heat treatment is performed in advance by performing heat treatment at 120 ° C. to 180 ° C. in accordance with the target heat shrinkage rate. Can be contracted.

The absolute humidity in each heating stage is preferably 15 g / m ³ or less, and more preferably heated in an atmosphere of 12 g / m ³ or less. Particularly in the first stage of heating, since the heating temperature is relatively low at 25 ° C. or more and less than 40 ° C., the amount of saturated water vapor is small, and when the absolute humidity exceeds 15 g / m ³ , the drying efficiency decreases, and the water contained in the coating film The time required to remove 60% by mass of the dispersion medium may be lengthened. For this reason, the absolute humidity is preferably 15 g / m ³ or less, particularly in the first stage of heating, and more preferably managed in an atmosphere of 12 g / m ³ or less in order to manage the humidity more stably.

  The heating temperature and humidity of each heating chamber are directly attached to a dummy substrate using the ultra-small button size temperature / humidity meter Hygrocron (KN Laboratories, Inc. (diameter 17 mm, thickness 10 mm)). Based on the measured value of the atmospheric temperature of the heating chamber every second, the temperature position at the center position of each heating chamber in each elapsed time is specified from the transport time and the length of each heating chamber, The wind speed for removing the dispersion medium was measured using a Kanomax anemometer (Anemomaster Model 6034) with a time constant set to 1 second and the wind speed fluctuation for 30 seconds measured in 1 second increments. The average value was taken as the wind speed.

  In the present invention, in order to remove the dispersion medium in each temperature region described above, the solvent removal step (B) may use a plurality of heating chambers depending on the heating time required for removing the water dispersion medium. It should be noted that a slit opening is provided between the heating chambers so that the base material passes, and the opening area of the slit opening is preferably 5% or more and less than 15% with respect to the cross-sectional area of the heating chamber. In order to suppress the mixing of hot air in the heating chamber adjacent from the opening, it is more preferably 5% or more and less than 10%. Moreover, it is preferable that the cylindrical junction part which interrupts | blocks a base material with external air between adjacent heating chambers is provided, and it is preferable that the length of the junction part in that case is 500 mm or less.

[Step (C)]
(C) A process is a process of apply | coating the 2nd coating liquid which dissolved the material used as a matrix in the solvent on the linear metal structure mounted on the base material at the said (B) process. Here, the matrix material is preferably composed of a polymer having a structure in which a compound having two or more carbon-carbon double bond groups contributing to the polymerization reaction is polymerized.

  Such a polymer comprises a composition comprising a monomer, an oligomer, or a polymer having two or more carbon-carbon double bond groups that contribute to the polymerization reaction, and a carbon-carbon double bond in the carbon-carbon double bond group. It is preferably a polymer compound obtained by vinyl polymerization (including diene polymerization) as a reaction point.

  As a method of applying the second coating liquid obtained by dissolving these matrix materials in a solvent onto the linear metal structure placed on the base material in the step (B), it is placed on the base material. A coating method that does not disturb the network structure of the linear metal structure is selected. For example, kiss touch type gravure coating, die coating, spin coating, spin coating, dip coating, ink jet, and the like can be mentioned. Among these, the slit die coating method that can form a coating film with high productivity is preferable.

  The coating thickness of the matrix applied on the conductive layer can be applied with a thickness suitable for the various coating methods described above, and is preferably 3 to 20 μm when slit die coating is used, and preferably 5 to 10 μm. More preferred. If the coating thickness exceeds 20 μm, the second coating film may flow during the conveyance of the substrate, and the uniformity of the film thickness of the matrix may be impaired. If it is less than 3 μm, it may be difficult to apply stably.

[Step (D)]
In step (D), the solvent is removed from the second coating liquid applied on the linear metal structure in step (C), and a conductive layer containing the linear metal structure in the matrix is formed on the substrate. It is a process of forming. In the step (C), the solvent is removed from the second coating liquid in which the matrix material applied on the linear metal structure is dissolved in the solvent. It is preferable to apply the same conditions as in the above-mentioned step (B) for setting the conditions for removing the solvent.

  By removing the solvent in this way, a conductive layer containing the linear metal structure in the matrix can be formed on the substrate. However, as a material for forming the matrix of the conductive layer, crosslinking can be performed after the solvent is dried. What can be reacted is preferable in terms of maintaining the smoothness of the surface.

  Examples of the crosslinking method include heating (hereinafter referred to as heat curing) and irradiation with an active electron beam such as ultraviolet light, visible light, and electron beam (hereinafter referred to as photocuring). In the case of photocuring, a photocuring crosslinking initiator as described later is contained, and active species can be generated simultaneously in the entire system by irradiating it with an active electron beam. It is preferable because the time required for the process can be shortened.

  In addition, when irradiating the active electron beam, it is also effective to use a specific atmosphere in which the oxygen concentration is lowered, such as in an atmosphere substituted with an inert gas such as nitrogen or argon, or in an atmosphere deoxygenated. It is more preferable to irradiate the active electron beam in a specific atmosphere with a low oxygen concentration.

[Surface resistance value and haze value of conductive laminate]
The surface resistance value on the conductive layer side of the conductive laminate according to the present invention is preferably 1 × 10 ⁰ Ω / □ or more and 1 × 10 ⁴ Ω / □ or less, more preferably 1 × 10 ¹ Ω / □. As described above, it is 1.5 × 10 ³ Ω / □ or less. By being in this range, it can be preferably used as a conductive laminate for a touch panel. That is, if it is 1 × 10 ⁰ Ω / □ or more, power consumption can be reduced, and if it is 1 × 10 ⁴ Ω / □ or less, the influence of errors in the coordinate reading of the touch panel can be reduced.

  The haze value of the conductive laminate is based on JIS K7136 (2000) when entering from the conductive layer side, and the haze value of the conductive laminate after forming the conductive layer and the conductive layer after forming the conductive layer. The value obtained from the haze difference is taken as the haze value of the conductive layer.

  As a method for reducing the haze value of the conductive laminate, in addition to the method of reducing the amount of the linear metal structure by improving the conductive efficiency of the network structure of the linear metal structure, the average diameter of the linear metal structure can be reduced. The method of selecting a small thing, the method of making a haze value small as a layer structure of a conductive laminated body, etc. are mentioned. It is preferable that the diameter of the linear metal structure is small because light scattering on the surface of the linear metal structure is small and the haze value is small.

Also, by increasing the surface average thickness of the matrix of the layer structure of the conductive laminate, the irregularities on the surface of the conductive laminate due to the linear metal structure are reduced, and by smoothing, the haze value due to scattering on the surface of the conductive laminate Can be suppressed. In addition, when brushing generate | occur | produces, glossiness reduces and the remarkable raise of a haze value is confirmed. The haze value and surface resistance value of these conductive laminates are correlated. In the present invention, as described above, by optimizing the solvent removal conditions and suppressing the occurrence of brushing, it is possible to achieve both high conductivity and high transparency. When the value is Y and the haze value is X, Y ≦ 331.32X− ^7.10 .

[Transmissivity of conductive laminate]
The conductive laminate according to the present invention is preferably a transparent conductive laminate having a total light transmittance of 80% or more based on JIS K7361-1 (1997) when incident from the conductive layer side.

  A touch panel in which the conductive laminate of the present invention is incorporated as a transparent conductive laminate exhibits excellent transparency, and the display of a display provided on the lower layer of the touch panel using the transparent conductive laminate can be clearly recognized.

  As a method for increasing the total light transmittance, for example, a method for increasing the total light transmittance of the base material to be used, a method for reducing the film thickness of the conductive layer, and an opposite surface of the base material provided with the conductive layer. Examples thereof include a method of providing a crosslinked layer having a refractive index smaller than that of the substrate, and a method of laminating so that the conductive layer becomes an optical interference film.

  As a method for increasing the total light transmittance of the base material, a method of reducing the thickness of the base material or a method of selecting a base material made of a material having a large total light transmittance can be mentioned.

  As the substrate in the conductive laminate of the present invention, a substrate having a high visible light total light transmittance can be preferably used. Specifically, the total light transmittance based on JIS K7361-1 (1997) is 80% or more. And more preferably 90% or more of transparency.

  Specific examples of a material for a base material (hereinafter simply referred to as a base material) having a total light transmittance of 80% or more based on JIS K7361-1 (1997) include transparent resins and glass. Examples of the resin include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamide, polyimide, polyphenylene sulfide, aramid, polyethylene, polypropylene, polystyrene, polylactic acid, polyvinyl chloride, polycarbonate, polymethyl methacrylate, etc. Acrylic / methacrylic resins, cycloaliphatic acrylic resins, cycloolefin resins, triacetyl cellulose, ABS, polyvinyl acetate, melamine resins, phenolic resins, elemental chlorine (Cl elements) such as polyvinyl chloride and polyvinylidene chloride Resin, resin containing elemental fluorine (F element), silicone resin, and a mixture and / or copolymerization of these resins are used. As glass, ordinary soda glass should be used. It can be. Moreover, these several base materials can also be used in combination. For example, a composite substrate such as a substrate in which a resin and glass are combined and a substrate in which two or more kinds of resins are laminated may be used.

[Base material]
Regarding the shape of the substrate, even if it is a film that can be wound up with a thickness of 250 μm or less, or a substrate with a thickness of more than 250 μm, it may be in the range of the total light transmittance. From the viewpoints of cost, productivity, handleability and the like, a resin film having a thickness of 250 μm or less is preferable, a resin film having a thickness of 190 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less. When using a resin film as a base material, what was made into the film by unstretching, uniaxial stretching, and biaxial stretching of resin can be applied.

  Among these resin films, from the viewpoint of moldability to a substrate, optical properties such as transparency, productivity, etc., polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and mixing with PEN and A copolymerized PET film or polypropylene film can be preferably used.

  Next, a method of laminating so that the conductive layer becomes an optical interference film is shown below.

  The conductive material (linear metal structure) reflects or absorbs light depending on the physical properties of the conductive component itself. Therefore, in order to increase the total light transmittance of the conductive laminate including the conductive layer provided on the base material, the matrix is made of a transparent material and the conductive layer is an optical interference film. It is effective to set the average reflectance at a wavelength of 380 to 780 nm to 4% or less, preferably 3% or less, more preferably 2% or less. When the average reflectance is 4% or less, a performance with a total light transmittance of 80% or more when used for touch panel applications can be obtained with good productivity.

  As described above, according to the production method of the present invention, after forming a conductive laminate using a paint in which a linear metal structure is dispersed in an aqueous dispersion medium, an organic solvent is used as a dispersion medium on the layer. When providing the used matrix layer, it is possible to provide a conductive laminate that is less likely to generate brushing, and while maintaining high conductivity, it has low haze and high transparency, and thus is preferably applied to a display body, In particular, the electrode member is suitably used for touch panel applications because it can provide clearness and conductivity to the electrode member. Furthermore, the conductive laminate of the present invention can be suitably used for display members such as liquid crystal displays, organic electroluminescence (organic EL), and electronic paper, and electrode members used in solar cell modules and the like.

  Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited to the following examples.

[Evaluation method]
First, an evaluation method in each example and comparative example will be described.

(1) Surface resistance value R ₀
The surface resistance value on the conductive layer side was measured at a central portion of a 100 mm × 50 mm sample by an eddy current method using a non-contact resistivity meter (NC-10 manufactured by Napson Co., Ltd.). An average value was calculated for 5 samples, and this was defined as a surface resistance value R ₀ [Ω / □]. When the surface resistance value was not obtained exceeding the detection limit, it was then measured by the following method.

  Using a high resistivity meter (Hiresta-UP MCP-HT450 manufactured by Mitsubishi Chemical Corporation), a ring type probe (URS probe MCP-HTP14 manufactured by Mitsubishi Chemical Corporation) is connected and 100 mm × 100 mm in a double ring system. The central part of the sample was measured. Five samples were measured and the average value was calculated.

(2) Haze value (cloudiness)
Based on JIS K7136 (2000) using a turbidimeter (cloudiness meter) NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.), the haze value in the thickness direction of five samples of the conductive laminate was measured from the conductive layer side. The haze value of the base material before forming the conductive layer and the conductive laminate after forming the conductive layer is measured, and the average value of the values obtained from the haze difference is determined as the haze value of the conductive layer. Value.

(3) Total light transmittance Total light transmittance in the thickness direction of the conductive laminate based on JIS K7361-1 (1997) using a turbidimeter (cloudiness meter) NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) Was measured by making light incident from the conductive layer side. Five samples were measured and the average value was calculated.

(4) Coating film thickness Using a multilayer film thickness measuring instrument SI-T10 (manufactured by Keyence Corporation), the film thickness of the coating film containing the linear metal structure was measured on the substrate.

[material]
<Base material>
The base materials used in each example and comparative example are shown below.
(1) Substrate A
・ Polyethylene terephthalate film (Lumilar (registered trademark) U48 manufactured by Toray Industries, Inc.)
・ Thickness 125μm
(2) Base material B
・ Polyethylene terephthalate film (Lumilar (registered trademark) U48 manufactured by Toray Industries, Inc.)
・ Thickness 50 μm.

<Conductive material>
The conductive materials used in each example and comparative example are shown below.
Conductive Material A “Silver Nanowire”
A silver nanowire conductive material (short axis: 50 to 100 nm, long axis: 20 to 40 μm) obtained by the method described in Example 1 (synthesis of silver nanowire) of JP-T-2009-505358.

Example 1
Using the conductive material A “silver nanowire” and using water as a dispersion medium, a silver nanowire dispersion liquid was obtained by the method disclosed in Example 8 (nanowire dispersion) of JP-T-2009-505358. . A dispersion medium was added to the silver nanowire dispersion so that the concentration of silver nanowires was 0.05% by mass to prepare a silver nanowire dispersion coating liquid. This silver nanowire-dispersed coating solution is coated with a conductive film with a thickness of 62.5 μm on one side of the substrate using a slit die coat with a stainless steel (shim) shim (shim thickness 50 μm). Formed.

In the first heating stage, after heating for 125 seconds at a heating temperature of 35 ° C. and an absolute humidity of 12 g / m ³ , the heating medium is heated for 63 seconds in the second and third heating stages to remove the dispersion medium from the coating film of the first coating liquid. And the linear metal structure was mounted on the base material.

  Next, an acrylic composition (Fulcure HC-6 manufactured by Soken Chemical Co., Ltd.) as a matrix material is blended to a solid content concentration of 1.5% by mass using ethyl acetate as a solvent to form a second coating liquid, and slit die coating Was applied on the linear metal structure under the condition of a shim plate thickness of 50 μm at a coating amount that would result in a calculated thickness of 8 μm.

The second coating liquid was heated at a heating temperature of 120 ° C. for 2 minutes, and then cured by irradiating with 80 mJ / cm ^{2 of} ultraviolet rays.

(Example 2)
Using the silver nanowire dispersion liquid and slit die coater used in Example 1, a conductive film was applied to one side of the substrate with a thickness of 50 μm. Thereafter, heating was performed at a heating temperature of 30 ° C. and an absolute humidity of 11 g / m ³ for 90 seconds, followed by heating in the second and third stages of heating for 40 seconds to form a conductive component.

(Example 3)
Using the silver nanowire dispersion liquid and slit die coater used in Example 1, a conductive film was applied with a thickness of 37.5 μm on one side of the substrate. Thereafter, heating was performed at a heating temperature of 38 ° C. and an absolute humidity of 14 g / m ³ for 60 seconds, followed by heating in the second and third stages of heating for 27 seconds to laminate the conductive component.

Example 4
Using the silver nanowire dispersion liquid and slit die coater used in Example 1, a conductive film was applied with a thickness of 25 μm on one side of the substrate. Thereafter, heating was performed at a heating temperature of 28 ° C. and an absolute humidity of 12 g / m ³ for 48 seconds, followed by heating in the second and third stages of heating for 25 seconds to form a conductive component.

(Comparative Example 1)
Using the silver nanowire dispersion liquid and slit die coater used in Example 1, a conductive film was applied with a thickness of 25 μm on one side of the substrate. Thereafter, heating was performed at a heating temperature of 20 ° C. and an absolute humidity of 12 g / m ³ for 45 seconds, and subsequently, heating was performed for 33 seconds in the second and third stages of heating to form a conductive component.

(Comparative Example 2)
Using the silver nanowire dispersion liquid and slit die coater used in Example 1, a conductive film was applied with a thickness of 25 μm on one side of the substrate. Thereafter, heating was performed at a heating temperature of 35 ° C. and an absolute humidity of 14 g / m ³ for 20 seconds, and subsequently heating was performed for 68 seconds in the second and third stages of heating to form a conductive component.

(Comparative Example 3)
Using the silver nanowire dispersion liquid and slit die coater used in Example 1, a conductive film was applied with a thickness of 25 μm on one side of the substrate. Thereafter, heating was performed at a heating temperature of 32 ° C. and an absolute humidity of 12 g / m ³ for 45 seconds, followed by heating for 10 seconds in the second and third stages of heating to form a conductive component.

(Comparative Example 4)
Using the silver nanowire dispersion liquid and slit die coater used in Example 1, a conductive film was applied with a thickness of 25 μm on one side of the substrate. Thereafter, heating was performed at a heating temperature of 32 ° C. and an absolute humidity of 18 g / m ³ for 45 seconds, and subsequently heating was performed for 33 seconds in the second and third stages of heating to form a conductive component.

  Since the conductive laminate of the present invention can provide sharpness and conductivity to an electrode member that uses the conductive laminate for a touch panel or the like, it is suitably used for touch panel applications. Furthermore, the conductive laminate of the present invention can be suitably used for display members such as liquid crystal displays, organic electroluminescence (organic EL), and electronic paper, and electrode members used in solar cell modules and the like.

DESCRIPTION OF SYMBOLS 1 Base material 2 Conductive layer 3 Matrix layer 4 Conductive layer 5 observed from a direction perpendicular to the laminated surface Linear metal structure 6 Contact formed by overlapping linear metal structures

Claims (6)

A method for producing a conductive laminate in which a conductive layer is provided on at least one of the substrates by the following steps (A) to (D), wherein (B1), (B2) and (B3) are heated in step (B) The manufacturing method of the electrically conductive laminated body characterized by applying conditions.
(A) Step (B) of forming a coating film by applying a first coating liquid in which a linear metal structure is dispersed in an aqueous dispersion medium to a substrate with a coating thickness of 10 to 100 μm. A) The step (C) is a matrix in which the aqueous dispersion medium is removed from the coating film of the first coating liquid formed on the base material in the step and the linear metal structure is placed on the base material. Applying the second coating solution in which the material is dissolved in a solvent on the linear metal structure placed on the substrate in the step (B) (D) on the linear metal structure in the step (C) In the step (B) of removing the solvent from the second coating liquid applied to the substrate and forming a conductive layer containing the linear metal structure in the matrix, the following (B1), ( The heating conditions of B2) and (B3) are included.
(B1) There is a heating stage of heating at 25 ° C. or more and less than 40 ° C. for 30 to 130 seconds (B2) The total heating time is 70 seconds or more (B3) Under an atmosphere with an absolute humidity of 15 g / m ³ or less Heating The method for producing a conductive laminate according to claim 1, wherein the linear metal structure is a metal fiber or a carbon nanotube. The method for producing a conductive laminate according to claim 2, wherein the metal fibers are silver nanowires. The display body using the electrically conductive laminated body obtained by the manufacturing method in any one of Claims 1-3. The touch panel using the conductive laminated body obtained by the manufacturing method in any one of Claims 1-3. Electronic paper using the electroconductive laminate obtained by the manufacturing method according to claim 1.

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