JP2012156031A - Conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductor whose orientation of a conductive linear structure is extremely small when a conductor is formed on a base material at room temperature under atmospheric pressure by dispersing a conductive linear structure in a solution, and which, when mounted on a display related XY electrode such as an electromagnetic shield, a liquid crystal display device, an organic electroluminescent element and an electronic paper or touch panel electrode, exhibits high position detection accuracy and hardly operates erroneously.SOLUTION: A conductive film includes a conductor layer containing a conductive linear structure on at least one surface of a base material. The conductive film, when a circle having a diameter of 70 μm in actual size is drawn at center of a photographed image of a location on the conductor layer selected at random, 18 straight lines passing through the center of the circle to divide the circle into 36 equal parts are drawn, the number of intersections of the conductive linear structure with the straight lines inside the circle is counted for each straight line, and a straight line whose number of intersections is the largest is assumed to be land a straight line whose angle formed with lis 90 degrees is assumed to be l, has a ratio of number of intersections n/n, i.e., a ratio of the number of intersections nof lto the number of intersections nof l, being 1.00 to 1.25.

Description

  Conductive materials used for wiring materials, conductive paste, electrode materials, electromagnetic wave shields, environmental catalysts, highest-functioning fuel cell catalysts, liquid crystal display devices, organic electroluminescence elements, display-related optical materials such as electronic paper and touch panel electrodes It is a film and its manufacturing method.

  In recent years, a conductive material using a conductive linear structure has attracted attention. In particular, nano-sized conductive linear structures such as carbon nanotubes and silver nanowires are expected to be used in various applications in the future. By dispersing and applying these linear structures in a solution, a conductive film can be formed at room temperature and atmospheric pressure, and a conductor can be formed by a simple process. Moreover, since it is rich in flexibility, even when a conductor is formed on a flexible substrate, it is possible to follow the flexibility of the substrate. Furthermore, when a film is used for the base material, the conductor can be continuously formed, so that the process cost can be further reduced. Moreover, it is possible to improve transparency by improving the dispersibility of these conductive linear structures in a solution, and it is rich in flexibility by forming a conductor on a transparent substrate. A transparent conductive film can be provided.

  Various methods for forming a conductor using a conductive linear structure have been proposed. However, in the case where a conductor is formed on a substrate by dispersing the linear structure in a solution, it is described in Patent Document 1. The bar coating method shows that the linear structures can be oriented in the same direction. In Patent Document 2, a conductive material is dispersed in a solution and applied to a uniaxially stretched film. Thereafter, a method of controlling the orientation by stretching in a direction perpendicular to the coating direction is shown. Further, in Patent Document 3, the orientation is controlled by applying a direct current electric field from one direction after a conductive linear structure made of carbon fiber is dispersed in a resin to form a film and then cured.

JP 2008-279434 A Japanese Patent Laid-Open No. 9-1753 JP 2006-312677 A

  In this way, it is difficult to arbitrarily adjust the orientation when a linear structure is dispersed in a solution and a conductor is formed on a substrate at room temperature and atmospheric pressure. It was a technical problem to be formed with. In view of such a problem, the present invention is a conductive material in which the orientation of the conductive linear structure is extremely small when the conductive linear structure is dispersed in a solution and the conductive material is formed on the substrate at room temperature and atmospheric pressure. Provides a conductor with high position detection accuracy and low malfunction when mounted on XY electrodes related to displays such as electromagnetic wave shield, liquid crystal display device, organic electroluminescence element, electronic paper and touch panel electrode For the purpose. It is another object of the present invention to provide a conductor by a simple process that enables the conductor to be formed at room temperature and atmospheric pressure in a state where the conductive linear structure is dispersed in a solution.

A conductive film having a conductive layer containing a conductive linear structure on at least one surface of a substrate, wherein the diameter is at the center of an image taken by randomly selecting a location on the conductive layer Draws a circle having an actual size of 70 μm, draws 18 straight lines that pass through the center of the circle and divides the circle into 36 equal parts, and the intersection of the conductive linear structure and the straight line inside the circle. counts the number for each straight line, when the straight corners is 90 degrees that forms the largest linear number of intersection points with l _0, l ₀ was l _90, the number n ₀ of the intersection of l ₀ and l crossing number which is a ratio of the number _{n 90} of the intersection of the _{90 n} 0 _{/ n 90} to provide a conductive film is 1.00 to 1.25.

  ADVANTAGE OF THE INVENTION According to this invention, the conductor with small orientation of a conductive linear structure can be formed, and the conductor with which the conductive anisotropy was improved simultaneously can be provided. Accordingly, it is possible to provide a conductor with high position detection accuracy and few malfunctions when mounted on an XY electrode related to an electromagnetic wave shield, a liquid crystal display device, an organic electroluminescence element, an electronic paper or a touch panel electrode. It becomes possible. In addition, since the conductor can be formed at room temperature and atmospheric pressure in a state where the conductive linear structure is dispersed in the solution, the conductor can be provided by a simple process. .

It is a figure which shows the example of drawing for measuring a crossing number ratio from an image. It is a figure which shows typically the sample cut-out position for inter-terminal resistance value measurement, and the inter-terminal resistance measurement position.

  First, the base material to which the conductive linear structure is applied will be described. In the present invention, examples of the substrate on which the conductive linear structure is applied include resin and glass. Examples of the resin include polyethylene terephthalate, polyethylene-2, 6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, cyclohexanedimethanol copolymer polyester resin, isophthalic acid copolymer polyester resin, spiroglycol copolymer polyester resin, fluorene copolymer polyester resin, etc. Polyester resins, polyethylene resins, polypropylene, polymethylpentene, polyolefin resins such as cyclic polyolefin copolymer resins, acrylic resins such as polymethyl methacrylate, polycarbonate, polystyrene, high impact polystyrene, styrene / acrylonitrile copolymers, methyl methacrylate・ Styrene copolymer, methyl methacrylate / butadiene / styrene copolymer, styrene / none Maleic acid copolymer, styrene / methacrylic acid copolymer, heat-resistant styrene resin copolymerized with α-methylstyrene or maleimide, styrene / acrylonitrile copolymer resin, α-methylstyrene / acrylonitrile copolymer Examples thereof include, but are not limited to, polymerized resins, polyphenylene ether resins, polyamides, polyethers, polyester amides, polyether esters, polyvinyl chloride, copolymers containing these components, and mixtures of these resins. Moreover, as glass, although normal soda glass can be used, it is not necessarily limited to this. Moreover, these several base materials can also be used in combination. Further, the substrate may be subjected to a surface treatment as necessary. The surface treatment may be a physical treatment such as glow discharge, corona discharge, plasma treatment, fire treatment, or a resin layer. When the substrate is a film, it may have an easy adhesion layer.

  Next, the conductive linear structure contained in the conductor layer will be described. In the present invention, the conductor layer needs to contain a conductive linear structure. In the present invention, the conductive linear structures preferably used are carbon nanotubes (hereinafter also referred to as CNT) and metal nanowires, and the metal composition of the metal nanowires is not particularly limited, and noble metal elements and noble metal oxides. Can be composed of one or a plurality of base metal elements, but is composed of noble metals (eg, gold, platinum, silver, palladium, rhodium, iridium, ruthenium, osmium, etc.) and iron, cobalt, copper, tin It is preferable to include at least one metal belonging to the group, and it is more preferable to include at least silver from the viewpoint of conductivity. Nanowires of noble metals and noble metal oxides that can be used as conductive linear structures are described in JP-T 2009-505358, JP-A 2009-129607, JP-A 2009-070660, Examples of the needle crystals such as whiskers or fibers of metal oxide include, for example, WK200B of DENTOR WK series (manufactured by Otsuka Chemical Co., Ltd.), which is a composite oxide of potassium titanate fiber, tin and antimony oxide. , WK300R and WK500 are commercially available. Examples of the base metal element include carbon nanotubes, and the carbon nanotubes may be single-walled, double-walled, or multi-walled carbon nanotubes having three or more layers. Those having a diameter of about 0.3 to 100 nm are preferably used. Since carbon nanotubes have the property of absorbing light, single-walled CNTs and double-walled CNTs having a diameter of 10 nm or less are more preferable in order to increase the transparency of the carbon nanotube conductor.

  Moreover, it is preferable that impurities such as amorphous carbon and catalytic metal are not contained in the aggregate of CNTs as much as possible. When these impurities are contained, they can be appropriately purified by acid treatment or heat treatment. This CNT is synthesized and manufactured by arc discharge method, laser application method, catalytic chemical vapor phase method (a method using a catalyst in which a transition metal is supported on a carrier in a chemical vapor phase method), etc. It is preferable that the production of impurities such as carbon can be reduced.

  In addition to the conductive linear structure, the conductor layer may contain a resin, and the resin can be used alone or in combination of two or more. As these resins, polyether diol, polyester diol, polycarbonate diol, polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, acetal group-modified polyvinyl alcohol, butyral group-modified polyvinyl alcohol, silanol group-modified polyvinyl alcohol, ethylene-vinyl Alcohol copolymer, ethylene-vinyl alcohol-vinyl acetate copolymer resin, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, acrylic resin, epoxy resin, modified epoxy resin, phenoxy resin, modified phenoxy resin, phenoxy ether resin, Phenoxy ester resin, fluorine resin, melamine resin, alkyd resin, phenol resin, polyacrylamid , Synthetic polymers such as polyacrylic acid, polystyrene sulfonic acid, polyethylene glycol, polyvinyl pyrrolidone, starch, pullulan, dextran, dextrin, guar gum, xanthan gum, amylose, amylopectin, alginic acid, gum arabic, carrageenan, chondroitin sulfate, hyaluronic acid, card Examples thereof include natural polymers such as orchid, chitin chitosan, cellulose, xylan, glucomannan, and arabinogalactan, and derivatives such as carboxymethyl cellulose, but are not limited thereto. The derivative means a conventionally known compound such as ester or ether.

  Next, the average length of the conductive linear structure will be described. In the present invention, the average length represents a number average. The average length of the conductive linear structure is preferably 15 μm or more. The average length of 15 μm or more is preferable because the aspect ratio increases as the average length increases, and the number of contacts decreases when the conductive linear structure forms a network to form a conductor. This is because the resistance can be reduced and the conductive efficiency is increased, so that high transparency can be maintained even in a state where high conductivity is maintained. Furthermore, since the flexibility is also improved, the flexibility of the substrate can be followed even when the conductor is formed on a flexible substrate. The reason why the thickness is preferably 30 μm or less is that when it is 30 μm or more, the manufacturing cost of the conductive linear structure is significantly increased in the current technology. Therefore, it is not limited to this range, and if chemical technology develops in the future and the average length of the conductive linear structure becomes commensurate with the manufacturing cost, there will be no problem even if the average length increases. There is no. A method for measuring the length of the electric linear structure will be specifically described. Three places are selected at random on the conductive film and photographed at a magnification of 3000 times with a scanning electron microscope. When the contrast between the conductive conductive linear structure and the substrate film is low and observation is difficult with a scanning electron microscope, photographing is performed using an atomic force microscope or the like. Trimming is performed so that the field of view of the captured image is a square field of view of an actual size of 100 μ × 100 μ to obtain an image for measurement. Next, a square having an actual size of 20 μ × 20 μ is drawn so that the center of the diagonal line overlaps the center of the captured image, and the lengths of all the conductive linear structures existing even in part in the square are measured, The average length is defined as the average length of the conductive linear structure.

  Next, a method for forming a conductor layer on a substrate will be described.

  In the present invention, as a method for forming the conductor layer, for example, cast, spin coat, dip coat, bar coat, spray, blade coat, slit die coat, gravure coat, reverse coat, screen printing, mold coating, print transfer, A wet coating method such as inkjet is used. In the present invention, in particular, a method using a slit die coat capable of forming a conductor uniformly and with good productivity is possible because it is possible to perform mass production at low cost by roll-to-roll.

  When applying a conductive linear structure with a slit die, a shim plate is introduced to determine the slit shape. The thickness of the shim plate needs to be selected according to the shape of the conductive linear structure. For example, the conductive linear structure having a mean length of 20-30 μm and a diameter of 0.05-1.0 μm is dispersed in the solution. When the conductor is formed by slit die coating using the coated coating material, the thickness of the shim plate is preferably 40 μm or more and 100 μm or less. When a shim plate of 40 μm or more is used, when the conductive linear structure passes through the inside of the slit die, the conductive linear structure is longer than 30 μm in the axial direction. It is preferable because it is easy to pass through, and disconnection and aggregation of the conductive linear structure are less likely to occur. This disconnection or aggregation of the conductive linear structure is easily imagined to cause non-uniformity of conductivity in the conductor after film formation, which may induce conductivity anisotropy. is there. When a thin shim plate of 100 μm or less is used, the amount of coating liquid supplied per unit time supplied to the inside of the slit die is extremely increased in order to secure pressure loss to an area where the coating liquid can be stably supplied. It is not necessary and preferable. In the case of a shim plate of 100 μm or less, the substrate conveyance speed is in the region where the coating is stabilized, the application of the coating liquid to the substrate is stable, the defects such as coating stripes do not occur, and the appearance quality is Since it can maintain high, it is preferable.

  Next, a process (hereinafter also referred to as a leveling process) from the application to the drying process will be described. In the present invention, after the application of the coating liquid containing the conductive linear structure, it was placed in an environment where the air velocity was 1.0 m / s or less and the temperature was 10 ° C. or more and 40 ° C. or less for 3 minutes or more. Thereafter, it is preferable to enter a drying step in which the solvent in the coating liquid is removed by drying. The leveling step time is more preferably 4 minutes or more and 10 minutes or less. Regarding the wind speed of the air current, the air speed of the air current is preferably 1.0 m / s or less. When it is 1.0 m / s or less, the conductive linear structure is not oriented in the wind direction due to the influence of the wind, and as a result, the conductive linear structure becomes non-oriented. More preferably, it is 0.1 m / s or more and 1.0 m / s or less. The reason why 0.1 m / s or more is preferable is that if it is set to 0.1 m or less, facility improvement is required, which leads to an increase in cost. Moreover, even if it is 0.1 m / s or less, the film conveyance speed is often 0.1 m / s or more, and eventually the realistic wind speed on the film is 0.1 m / s or more. .1m or less is not technically meaningful. In addition, it is preferable to place it in an environment where the wind speed is 1.0 m / s or less for 3 minutes or longer because the orientation of the conductive linear structure that has been oriented at the time of coating is relaxed with time and approaches non-oriented. Further, the reason why 4 minutes or more is preferable is that the alignment becomes more non-oriented by placing it for 4 minutes or more. Furthermore, since the time until the start of drying is further prolonged, which leads to improvement of defects in coating omission, it is preferable to increase the time from the viewpoint of quality improvement. The reason why 10 minutes or less is preferable is to prevent the production efficiency from being lowered. This is because if it is 10 minutes or longer, the coating speed must be reduced or the process must be lengthened, resulting in an increase in cost, which may be undesirable. Therefore, it is desirable to determine the time to leave the product in consideration of cost and quality.

  Next, the drying process will be described. The drying process is desirably performed at 50 ° C. or higher and 200 ° C. or lower. The reason why 50 ° C. or higher is preferable is that the drying process time is shortened and the production efficiency is increased. The reason why the temperature is preferably 200 ° C. or lower is that when the temperature is 200 ° C. or higher, the film itself may be deteriorated.

  In a continuous process, as a method of leaving for 3 minutes or more in an environment where the wind speed is 1.0 m / s or less, it is preferable to increase the line length to the drying step because production efficiency can be maintained. The standing temperature is preferably 10 ° C. or higher and 40 ° C. or lower. When the temperature is 10 ° C. or higher, it is preferable because the orientation relaxation easily proceeds and the standing time can be shortened. A temperature of 40 ° C. or lower is preferable because drying of the coating liquid can be suppressed and slowing of orientation relaxation due to drying can be suppressed.

  Next, the viscosity of the coating liquid will be described. The absolute viscosity at 25 ° C. is preferably from 0.5 mPa · s to 60 mPa · s. The reason why 60 mPa · s or less is preferable is that when it is 60 mPa · s or less, the orientation relaxation rate is increased and the orientation is further reduced. Moreover, it is because it may be unable to apply | coat at the time of apply | coating depending on the apply | coating method as it is 0.5 mPa * s or less.

In this way, the conductive linear structure included in the conductor layer formed on the substrate has an actual size at the center of the image photographed by randomly selecting a location on the conductor layer. Draw a circle corresponding to 70 μm, draw 18 straight lines that pass through the center of the circle and divide the circle into 36 equal parts, and calculate the number of intersections of the conductive linear structure and the straight line inside the circle. counting each, when the straight corners is 90 degrees that forms the largest linear number of intersection points with _l 0, _{l 0} was _{l 90,} the intersection of several _{n 0} and _{l 90} of the intersection of _{l 0} crossing number ratio _n 0 _{/ n 90} is the ratio of the number _{n 90} of it is required to be 1.25 or less. This crossing number ratio approaches 1 as the orientation approaches non-orientation. When the intersection number ratio is 1.25 or more, the conductive anisotropy is increased due to the conductive linear structures being oriented in the same direction. Specifically, the image capturing for obtaining such a crossing number ratio is performed as follows. For example, a microscope capable of photographing at a magnification of 3000 times such as a KEYENCE laser microscope (VK-9700) is used to photograph at a magnification of 3000 times. When the contrast between the conductive conductive linear structure and the substrate film is low and observation is difficult by laser microscope observation, photographing is performed at a magnification of 3000 times with a scanning electron microscope or a transmission electron microscope. . A circle with a diameter of 70 μm is drawn at the center of the captured image.
Next, using the image processing apparatus such as MVtech's HALCON, the photographed image is drawn by drawing 18 straight lines that pass through the center of the circle and divide the circle into 36 equal parts. The number of intersections between the line structure and the straight line is counted for each straight line to obtain the number of intersections. Here the intersection number of the largest straight _l 0, when the angle formed between _{l 0} has a line 90 degrees with _{l 90,} the number of the intersections of said number _{n 0} of intersection, and _{l 90} of _{l 0} n _Assume that the intersection number ratio is obtained from the intersection number ratio n ₀ / n ₉₀ which is a ratio of ₉₀ .

  Regarding the conductive anisotropy, a reference line is drawn in an arbitrary direction on the conductive film obtained as described above, and the measurement direction is 0 °, 30 °, 60 °, 90 ° with respect to the reference line. When 12 samples of 30 mm squares with 120 ° and 150 ° are attached in each direction and cut into 12 pieces, and the inter-terminal resistance value R (kΩ) in the measurement direction is measured for each sample, The ratio (Rmax / Rmin) of the maximum value Rmax and the minimum value of Rmin between terminals is preferably 1.40 or less, more preferably 1.1 or less. When the crossing ratio of the conductive linear structures is 1.25 or less, these values are 1.40 or less, and the conductors are cut out in random directions as wiring materials, conductive pastes, and electrode materials. However, it is preferable because an arbitrary amount of current can be uniformly transmitted to the circuit to be used. In addition, when it is 1.1 or less, when it is used for display-related optical materials such as electromagnetic wave shields, liquid crystal display devices, organic electroluminescence elements, electronic paper and touch panel electrodes, etc. This is preferable because it can be applied to applications that require higher-precision detection, such as eliminating the need for software to correct the inconvenience induced by the conductive anisotropy. Note that this software correction does not require any special advanced technology, so it can be used technically for display-related optical materials, but it is used because it can avoid high costs for introducing software. It is preferable that it is not necessary. In addition, it is thought that this crossing number ratio and the value of conductive anisotropy have the following relationship. That is, the number of conductive linear structures intersecting the conductive paste applied when measuring the resistance value between the terminals represents the number of intersections, and the increase in the number of intersections increases the number of conductive paths and improves the conductivity. Thus, the resistance value between the terminals decreases, but if there is a difference in the number of intersections, that is, if the ratio of the number of intersections is greater than 1.25, a difference in conductivity occurs, and the ratio of the resistance values between the terminals also becomes greater than 1.40 . The inter-terminal resistance value measurement is performed in order to know the volume resistance value of the conductor. Although the volume resistance value can be measured even with a measuring machine equipped with a four-terminal method or an eddy current method, it is preferable to measure the resistance value between terminals in order to know the volume resistance value with respect to a certain potential direction.

The surface resistance of the conductor layer of the present invention is preferably 1Ω / □ or more and 1 × 10 ⁴ Ω / □ or less. By being in this range, it can be used for wiring materials and electrode materials in the low resistance region, and in other regions, for electromagnetic wave shields, liquid crystal display devices, organic electroluminescence elements, electronic paper and touch panel electrode touch panels. It can be preferably used as a conductor.

  The thickness of the conductor is not particularly limited and can be appropriately selected according to the purpose. However, since the transparency is improved as the thickness is reduced, the thickness of the conductor is within a range that provides transparent conductivity according to the intended use. A film can be formed. By providing such a conductor with improved transparency on the surface of a transparent substrate, it can be used as a functional material such as a visible light / near infrared light absorption filter or a conductive film.

  Various functional layers such as a hard coat layer, a non-glare coat layer, a barrier coat layer, an anchor coat layer, a carrier transport layer, and a carrier accumulation layer can be added to the conductor as necessary. These layers may be provided on the side on which the conductor is formed or on the opposite side across the base material, and can be applied according to the use.

Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited to the following examples. First, an evaluation method in each example and comparative example will be described.

(1) Select a random location on the conductive film of the conductive linear structure contained in the conductor layer, and shoot at a magnification of 3000 times with a KEYENCE laser microscope (VK-9700). went. In the case of observation with a laser microscope, when the contrast between the conductive conductive linear structure and the substrate film is low and observation is difficult, photographing is performed with a scanning electron microscope or a transmission electron microscope. The field of view of the photographed image was trimmed so as to be a circular field having an actual size of 70 μ × 70 μ to obtain an image for measuring the number ratio.
Next, using the MVtech HALCON, the above-mentioned photographed image is drawn so that 18 straight lines with a length of 70 μm passing through the center of the circular field of view are at an angle of 10 ° with the adjacent straight line, and the conductivity for each straight line is drawn. The number of intersections of the linear structures was determined. Here, the maximum value of the number of intersections is n ₀ , the straight line at that time is l ₀ , and the number of conductive linear structures intersecting with the straight line l ₉₀ where the angle formed by l ₀ is 90 degrees is n ₉₀ . At that time, the ratio of the number of crossings was determined by n ₀ / n ₉₀ .

(2) Average length of conductive linear structure A place was randomly selected on the conductive film, and images were taken at a magnification of 3000 times with a scanning electron microscope (type name). When the contrast between the conductive conductive linear structure and the substrate film is low and observation is difficult with a scanning electron microscope, photographing is performed using an atomic force microscope or the like. Trimming was performed so that the field of view of the photographed image was a circular field of actual size of 100 μ × 100 μ, and an image for measurement was obtained. Next, a square with an actual size of 20 μ × 20 μ is drawn so that the center of the diagonal line overlaps the center of the photographed image, and the lengths of all the conductive conductive linear structures existing at least partially in the square are measured. And the average length was made into the average length of a conductive linear structure.

(3) Resistance value between terminals A reference line is drawn in an arbitrary direction on the conductive film, and the measurement direction is 0 °, 30 °, 60 °, 90 °, 120 °, and 150 ° with respect to the reference line. The square sample is cut into 12 pieces in each direction, and 12 pieces are cut out, and a conductive paste ECM-100AF (registered trademark) made by Taiyo Ink Co., Ltd. has a thickness of 80 μm at the rotation outer end and rotation inner end 5 mm width of each sample. And dried at 90 ° C. for 60 minutes, and the dried conductive paste portion was measured using a digital tester CDM-17D (registered trademark) manufactured by Custom Co., Ltd.

(4) Viscosity measurement Viscosity measurement was carried out in accordance with JISK7117-2 (1999), a method for measuring viscosity at a constant shear rate with a rotational viscometer-Appendix A coaxial-Double cylindrical viscometer-. . The measurement conditions are as follows.
Measuring instrument: Bohlin Gemini HR nano (Malvern)
Test temperature: 25 ° C
Shear rate: 250 / s
(5) The wind velocity angle of the air current in the coating process of the solution containing the conductive linear structure is 2 cm at the tip at a position of 2 cm on the substrate to be coated in the process until the conductive film immediately after coating enters the drying process. The bar with the thread was placed parallel to the substrate and measured. Here, for the measurement, a polyester filament multifilament having a thickness of 140 dtex was used. In this measurement, it is not necessary to limit to this as long as it is a multifilament, and in addition to the polyester fiber, a polyamide fiber, a polyurethane fiber, or the like may be used.
The measurement of the wind speed of the air current is performed by using the anemometer VelociCalc Plus multi-parameter anemometer (model number: 8386A-M-GB) in the step of leaving the conductive film immediately after application, and the air current angle is 1 cm above the substrate to be applied. The wind speed of only the airflow at the angle measured by the above measurement method was measured. At a certain point on the substrate, the measurement surface of the probe was measured at the angle measured above, and the wind speed was measured for 30 seconds in a stationary state when receiving the wind speed of the airflow. The maximum value measured for 30 seconds was taken as the wind speed of the airflow.

(6) The temperature in the coating process of the solution containing the conductive linear structure is as follows: CLIMOMASTER (MODEL 6531 Nippon Kanomax Co., Ltd.) 1 cm above the substrate to be coated in the process until the conductive film immediately after coating enters the drying process. )). The temperature was measured at 1 cm above the center of the surface on which the coating liquid containing the conductive linear structure of the substrate was applied for 30 seconds or more, and the temperature was taken as a stable value.
Example 1
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition of a shim plate thickness of 50 μm, and left for 5 minutes and 20 seconds in an environment where the air velocity of the airflow is 1.0 m / s or less and the temperature is 25 ° C. A conductor was provided by drying at a drying temperature of 150 ° C. for 30 seconds. At this time, the value of Ra / Rb is 1.13, and the ratio of the number of crossings of the conductive linear structures n ₀ / n ₉₀
Was 1.07.
(Example 2)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition of a shim plate thickness of 50 μm, and left for 4 minutes and 20 seconds in an environment where the air velocity of the airflow is 1.0 m / s or less and the temperature is 25 ° C. A conductor was provided by drying at a drying temperature of 150 ° C. for 30 seconds. At this time, the value of Ra / Rb was 1.17, and the crossing number ratio n ₀ / n ₉₀ of the conductive linear structure was 1.00.
(Example 3)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition of a shim plate thickness of 50 μm, and left for 3 minutes and 20 seconds in an environment where the air velocity is 1.0 m / s or less and the temperature is 25 ° C. A conductor was provided by drying at a drying temperature of 150 ° C. for 30 seconds. At this time, the value of Ra / Rb was 1.32 and the crossing number ratio n ₀ / n ₉₀ of the conductive linear structure was 1.00.
Example 4
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition that the shim plate thickness is 50 μm, and the air velocity is 1.0 m / s or less and the temperature is 25 ° C. A conductor was provided. At this time, the value of Ra / Rb was 1.13, and the crossing number ratio n ₀ / n ₉₀ of the conductive linear structure was 1.02.
(Comparative Example 1)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition of a shim plate thickness of 50 μm, and left for 20 seconds in an environment where the air velocity is 1.0 m / s or less and the temperature is 25 ° C., and then the drying temperature It dried at 150 degreeC for 30 second, and provided the conductor. At this time, the value of Ra / Rb was 1.93, and the number ratio of the conductive linear structures was 1.45.
(Comparative Example 2)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition that the shim plate thickness is 50 μm, and the drying temperature after being left for 50 seconds in an environment where the air velocity is 1.0 m / s or less and the temperature is 25 ° C. It dried at 150 degreeC for 30 second, and provided the conductor. At this time, the value of Ra / Rb was 1.79, and the number ratio of the conductive linear structures was 1.41.
(Comparative Example 3)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition of a shim plate thickness of 50 μm, and left in an environment where the air velocity is 1.0 m / s or less and the temperature is 25 ° C. for 1 minute and 20 seconds. A conductor was provided by drying at a drying temperature of 150 ° C. for 30 seconds. At this time, the value of Ra / Rb was 1.59, and the number ratio of the conductive linear structures was 1.37.
(Comparative Example 4)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition of a shim plate thickness of 50 μm, and after standing for 4 minutes in an environment where the air velocity is 3.1 m / s and the temperature is 35 ° C., the drying temperature is 150 The film was dried at 30 ° C. for 30 seconds to provide a conductor. At this time, the value of Ra / Rb was 2.26, and the number ratio of the conductive linear structures was 1.65.
(Comparative Example 5)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition that the shim plate thickness is 50 μm, and the air temperature is 1.0 m / s or less and the temperature is 5 ° C. and left for 4 minutes, and then the drying temperature It dried at 150 degreeC for 30 second, and provided the conductor. At this time, the value of Ra / Rb was 1.71, and the number ratio of the conductive linear structures was 1.40.
(Comparative Example 6)
A silver nanowire dispersion (average length 20.2 μm, absolute viscosity) on one side of a substrate using a slit die coat with a 125 μm thick polyethylene terephthalate film, Lumirror (registered trademark) U48 (manufactured by Toray Industries, Inc.). : 4.5 mPa · s) under the condition that the shim plate thickness is 50 μm, and the air temperature is 1.0 m / s or less, and the temperature is 60 ° C. and left for 4 minutes, and then the drying temperature It dried at 150 degreeC for 30 second, and provided the conductor. At this time, the value of Ra / Rb was 1.58, and the number ratio of the conductive linear structures was 1.30.

1 Circle with actual diameter of 70 μm 2 Terminal location for measuring resistance between terminals

Claims (4)

A conductive film having a conductive layer containing a conductive linear structure on at least one surface of a substrate, wherein the diameter is at the center of an image taken by randomly selecting a location on the conductive layer Draws a circle having an actual size of 70 μm, draws 18 straight lines that pass through the center of the circle and divides the circle into 36 equal parts, and the intersection of the conductive linear structure and the straight line inside the circle. counts the number for each straight line, when the straight corners is 90 degrees that forms the largest linear number of intersection points with l _0, l ₀ was l _90, the number n ₀ of the intersection of l ₀ and l crossing number which is a ratio of the number _{n 90} of the intersection of the _{90 n} 0 _{/ n 90} is from 1.00 to 1.25 electroconductive film.   The conductive film according to claim 1, wherein an average length of the conductive linear structure is 15 μm or more.   A reference line is drawn on the conductive film in an arbitrary direction, and each 30 mm square sample having a measurement direction of 0 °, 30 °, 60 °, 90 °, 120 °, and 150 ° is measured with respect to the reference line. When 12 pieces are cut out as 2 pieces in the direction and the resistance value R (kΩ) between the terminals in the measurement direction is measured for each sample, the ratio (Rmax / Rmin) between the maximum value Rmax and the minimum value Rmin between the samples is It is 1.00-1.40, The electroconductive film of Claim 1 or 2.   The absolute viscosity of the coating liquid containing the conductive linear structure is 0.5 to 60 mPa · s, the wind speed of the airflow after applying the coating liquid is 1.0 m / s or less, and the temperature is 10 The production method for producing a conductive film according to any one of claims 1 to 3, wherein the solvent in the coating solution is removed by drying after being placed in an environment at -40 ° C for 3 minutes or more.