JP6693511B2 - Transparent conductive film and method for producing transparent conductive film - Google Patents

Description

  The present invention relates to a transparent conductive film and a method for manufacturing a transparent conductive film. More specifically, the present invention relates to a transparent conductive film having excellent adhesion between a conductive layer and a resin base material, having good conductivity and transparency, and a method for producing a transparent conductive film.

  In recent years, a transparent conductive film in which a conductive layer is laminated on a resin substrate of various display devices (devices) such as liquid crystal displays, plasma displays, inorganic and organic EL (electroluminescence) displays, touch panels, and solar cells has been used. Has been done.

  For devices equipped with a transparent conductive film, at the same time as the demand for larger screens, lighter weight and thinner devices, it is necessary to achieve both higher image quality, operational accuracy and response speed, and high electrical conductivity and transparency. It's more important than ever. However, as the device becomes larger in screen size, the user will be able to view the image in a wider angle, resulting in interference fringes and color unevenness on the screen when the display device is viewed from an oblique direction. The decrease in visibility is an important issue.

With respect to the above problem, a method of improving visibility by using a cycloolefin resin by setting the in-plane retardation (Ro value) of the resin base material within a range of ± 50 nm is disclosed (for example, patents Reference 1).
When a conductive layer is formed using a cycloolefin resin as the resin base material, a coating method is used to suppress dimensional changes of the resin base material and unevenness of the conductive layer thickness, which may cause deterioration in device performance. It is desired to form the conductive layer using a wet process such as the ink jet method, the coating method, and the dip method, and the adhesion with the water-soluble conductive layer coating liquid (ink) used in the wet process. Is required to improve.

  Further, a method of improving adhesion by performing corona treatment, atmospheric pressure plasma treatment, or excimer UV treatment on a resin substrate has been disclosed (see, for example, Patent Document 2), but these methods have high processing energy. Therefore, there is a demand for a method capable of forming a smooth conductive layer without requiring high processing energy.

JP, 2014-54760, A JP, 2005-12046, A

  The present invention has been made in view of the above problems and circumstances, and its problem to be solved is excellent in adhesion between a conductive layer and a resin substrate, and a transparent conductive film and a transparent conductive film having good conductivity and transparency. A method of manufacturing a conductive film is provided.

The inventor of the present invention, as a result of extensive studies to solve the above problems, contains a specific amount of a metal component in the resin substrate surface layer portion, and, in the surface layer portion of the resin substrate, by having a specific water content. The inventors have found that the above problems can be solved and have reached the present invention.
That is, the above-mentioned subject concerning the present invention is solved by the following means.

1. A transparent conductive film having a resin substrate and a conductive layer,
The main component of the resin base material is a cycloolefin resin,
The surface layer portion of the resin base material contains a metal component in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%, and
When the resin base material is immersed in water, the water content per unit volume of the surface layer portion of the resin base material is in the range of 120 to 300% with respect to the water content per unit volume of the middle layer portion of the resin base material. A transparent conductive film, characterized in that it is adjusted to be inside.

  2. The transparent conductive film according to item 1, wherein the metal component contains any one of gold, silver, copper, iron, aluminum, nickel, magnesium, zinc and alloys thereof.

  3. The said electroconductive layer is a metal electroconductive layer, The transparent electroconductive film of Claim 1 or 2 characterized by the above-mentioned.

4. A method for producing a transparent conductive film for producing a transparent conductive film having a resin substrate and a conductive layer ,
A cycloolefin resin, and an organic polar solvent, in the step of forming the organic non-polar solvent, a resin substrate by using a resin composition containing a water solution casting method, included in the resin composition By changing the amount of water, the amount of metal component, and the drying temperature, the content of the metal component in the surface layer portion of the resin base material becomes within the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%. And when the resin base material is immersed in water, the water content per unit volume of the surface layer portion of the resin base material is 120 with respect to the water content per unit volume of the middle layer portion of the resin base material. The method for producing a transparent conductive film is characterized in that it is adjusted to fall within the range of 300%.

  5. The method for producing a transparent conductive film according to item 4, wherein the conductive layer is formed by an inkjet method.

  According to the above means of the present invention, it is possible to provide a transparent conductive film having excellent adhesion between the conductive layer and the resin substrate, having good conductivity and transparency, and a method for producing the transparent conductive film.

The mechanism of action or mechanism of action of the present invention has not been clarified, but is presumed as follows.
By setting the water content per unit volume of the surface layer portion of the resin base material within the range of 120 to 300% with respect to the water content per unit volume of the middle layer portion of the resin base material, the conductive layer coating liquid is obtained. Permeability is improved. Moreover, when the content of the metal component in the surface layer portion of the resin base material is contained within the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%, the interaction with the conductive material contained in the conductive layer is achieved. It is assumed that excellent adhesion is obtained between the resin substrate and the conductive layer, and a transparent conductive film having good conductivity and transparency can be obtained.

Schematic diagram showing an example of the layer structure of the transparent conductive film of the present invention

The transparent conductive film of the present invention is a transparent conductive film having a resin substrate and a conductive layer, the main component of the resin substrate is a cycloolefin resin, the surface layer portion of the resin substrate is , Containing a metal component in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%, and when the resin base material is immersed in water, per unit volume of the surface layer portion of the resin base material. The water content of is adjusted to be in the range of 120 to 300% with respect to the water content per unit volume of the middle layer portion of the resin base material.
This feature is a technical feature common to the inventions according to each claim.

  As an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, the metal component contains any one of gold, silver, copper, iron, aluminum, nickel, magnesium, zinc and alloys thereof. From the viewpoint of adhesion between the conductive layer and the resin substrate, conductivity, or transparency.

  Further, in the present invention, it is preferable that the conductive layer is a metal conductive layer from the viewpoint of the adhesiveness or conductivity between the conductive layer and the resin substrate.

As a method for producing a transparent conductive film for producing the transparent conductive film of the present invention, a solution flow using a resin composition containing a cycloolefin resin, an organic polar solvent, an organic nonpolar solvent, and water. In the step of forming the resin base material by the rolling method, the content of the metal component in the surface layer portion of the resin base material is changed by changing the amount of water contained in the resin composition, the amount of metal component, and the drying temperature. Water content per unit volume of the surface layer portion of the resin substrate when the resin substrate is immersed in water and adjusted to be in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%. However, it is preferable from the viewpoint of manifesting the effects of the present invention that the water content per unit volume of the middle layer portion of the resin substrate is adjusted to be in the range of 120 to 300%.

  Further, in the present invention, it is preferable that the conductive layer is formed by an inkjet method from the viewpoint of enhancing the adhesion between the conductive layer and the resin substrate.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in the present invention is used to mean that the numerical values described before and after that are included as the lower limit value and the upper limit value.

<< Transparent conductive film >>
The transparent conductive film of the present invention has a resin base material and a conductive layer, a main component of the resin base material is a cycloolefin resin, and a surface layer portion of the resin base material has a metal component of 1 ×. It is contained in the range of 10 ⁻⁶ to 1 × 10 ⁻³ mass%, and when the resin base material is immersed in water, the water content per unit volume of the surface layer portion of the resin base material is It is adjusted to be in the range of 120 to 300% with respect to the water content per unit volume of the middle layer portion of the resin substrate.
FIG. 1 shows an example of an embodiment of the transparent conductive film of the present invention. In the transparent conductive film 1 of the present invention, it is preferable that the resin base material 2 and the conductive layer 4 are in contact with each other from the viewpoint of enhancing the adhesion between the conductive layer and the resin base material.
Further, the water content per unit volume of the surface layer portion 3 of the resin base material 2 is adjusted to be within a range of 120 to 300% with respect to the water content per unit volume of the middle layer portion 5 of the resin base material 2. ing.
Here, the surface layer portion refers to a range from the surface of the resin base material to a thickness of 0.1 μm in the thickness direction of the resin base material.
Further, the middle layer portion of the resin base material refers to a region closer to the inside of the resin base material than the two surface layer portions of the resin base material.
Incidentally, the transparent conductive film of the present invention, it is preferable that the resin substrate and the conductive layer are in contact with each other as described above, but provided that it is a layer that does not impair the adhesion, it is provided between the resin substrate and the conductive layer. May be.

<Resin base material>
The resin base material according to the present invention may contain a cycloolefin resin as a main component, that is, the resin composition forming the resin base material in the highest proportion, and may contain other resin materials or compounds. .. Further, it may have a single layer or a multilayer structure. In the case of a multi-layer structure, it may have at least one layer formed from a resin composition containing a cycloolefin resin as a main component, but from the viewpoint of enhancing the adhesion between the conductive layer and the resin substrate. The surface layer portion of the resin substrate is preferably a layer formed from a resin composition containing a cycloolefin resin as a main component.
The material used as the resin substrate is not particularly limited, and examples thereof include norbornene-based resins (for example, polyesters such as ARTON (manufactured by JSR), polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, cellophane, cellulose acetate, cellulose acetate butyrate). Rate, cellulose acetate phthalate, cellulose acetate propionate, cellulose triacetate, cellulose esters such as cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl alcohol, syndiotactic polystyrene resin, polycarbonate, Zeonex, ZEONOR (manufactured by Zeon Corporation), polymethylpentene, polyetherketone, polyethersulfo , Mention may be made of polysulfone-based resin, polyether ketone imide, polyamide, acrylic or polyacrylate resins. The present invention includes norbornene-based resins, cellulose esters such as cellulose triacetate (TAC), polycarbonates, polyesters or polyacrylics.
The material containing the resin base material as a main component and the content of the metal component are obtained by nuclear magnetic resonance spectroscopy.

As the water content of the resin base material, the mass of the resin base material measured under an environment of 23 ° C. and 55% and the mass after the resin base material was immersed in water for 48 hours were measured, and both measured values were obtained. Was calculated (the amount of change), and the water content per unit volume was taken as the water content of the entire resin substrate.
Specifically, the water content of the middle layer portion of the resin base material was measured in an environment of 23 ° C. and 55% after spattering copper on both sides of the resin base material and removing the surface layer portion of the resin base material. The difference (increase) between the mass of the resin base material and the mass after soaking in water for 48 hours is determined, and the water content per unit volume is the water content of the middle layer part. Further, the value obtained by subtracting the water content per unit volume of the obtained middle layer portion from the water content per unit volume of the entire resin substrate after being immersed in water for 48 hours is the water content per unit volume of the surface layer portion. It becomes the amount of water.

In the present invention, the water content per unit volume of the surface layer portion of the resin substrate is characterized by being in the range of 120 to 300% with respect to the water content per unit volume of the middle layer portion of the resin substrate.
In the present invention, the water content per unit volume of the surface layer portion of the resin base material is 120% or more relative to the water content per unit volume of the middle layer portion of the resin base material, so that the conductive layer coating liquid is obtained. Good penetration is obtained. By permeating the conductive layer coating liquid into the resin base material, it is possible to suppress reflection of transmitted light that occurs at the interface between the resin base material and the conductive layer. Further, by setting the water content per unit volume of the surface layer portion of the resin base material to 300% or less, the coating liquid for the conductive layer excessively permeates the resin base material, and the conductive layer is thinned to reduce the conductivity. It is possible to suppress a decrease in the rate. From the viewpoint of conductivity and transparency, the water content per unit volume of the middle layer of the resin base material is more preferably within the range of 150 to 250%.
The water content can be appropriately adjusted depending on the production conditions of the film, the production conditions of the resin base material to be produced, the film thickness, and the like.

The equilibrium water content of the resin base material according to the present invention at 23 ° C. and 80% relative humidity is preferably 3% or less from the viewpoint of phase difference variation and bending resistance, and more preferably 1% or less. By setting the equilibrium water content to 3% or less, it is easy to cope with a change in humidity and the optical characteristics and dimensions are less likely to change, which is preferable.
The equilibrium water content is determined by leaving the sample film in a room conditioned at 23 ° C and a relative humidity of 20% for 4 hours or more, and then in a room conditioned at 23 ° C / 80% RH for 24 hours at a temperature of 150 ° C. After the water is dried and vaporized by, the sample is quantified by the Karl Fischer method using a trace moisture meter (for example, Mitsubishi Chemical Corporation CA-20 type).

The metal component according to the present invention preferably contains any one of gold, silver, copper, iron, aluminum, nickel, magnesium, zinc and alloys thereof.
The amount of metal components contained in the surface layer portion of the resin base material is in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%, and the preferable range is 1 × 10 ^{−5 to} 5 × 10 ^−4. It is% by mass. When the content is 1 × 10 ⁻³ mass% or less, when the transparent conductive film of the present invention is used in a touch panel, electricity diffuses inside the transparent conductive film, which causes noise and reduces the sensor sensitivity. Can be suppressed.

As for the method for measuring the metal component of the surface layer part, the transparent conductive film is immersed in a methyl ethyl ketone solution to dissolve only the surface layer part. After the solvent was completely diluted from the obtained liquid, it was ashed in an electric furnace, and then the mixture was heated and dissolved with nitric acid and diluted with ultrapure water, and then ICP emission spectrometry (ICP-AES) The amount of metal was measured at.
The amount of the metal component in the surface layer portion was calculated from the mass of the resin component in the surface layer portion obtained from the solution and the amount of metal obtained by the measurement.

  As one embodiment for localizing the metal component on the surface layer of the resin substrate, in the case of producing the resin substrate by the solution casting method, the resin composition used in the present invention (hereinafter, also referred to as a dope) The difference between the boiling points of the mixed solvent contained in (.) And the solubility of the mixed solvent and the metal component are utilized.

  Specifically, when the dope is cast on a support and dried on the support, the dope is volatilized from the surface opposite to the support, thereby producing a distribution in the thickness direction on the support. If it is a mixed solvent, it is volatilized from the low boiling point solvent, so that the low boiling point solvent and the high boiling point solvent are distributed in the thickness direction. At this time, due to the solubility of the metal component, the film after drying is localized in the thickness direction. If the solubility of the metal component in the low-boiling point solvent is higher than that in the high-boiling point solvent, the compound is biased in the direction of volatilization of the low-boiling point solvent (opposite to the support), so that the compound is localized near the surface. Incarnate.

<Conductive layer>
The conductive layer according to the present invention is preferably a metal conductive layer made of a metal or a metal oxide. The conductive material contained in the conductive layer coating liquid used when forming the conductive layer is not particularly limited, but examples thereof include fine particles of silver, copper, copper / nickel alloy or a fired body thereof, and conductive polymer. Can be preferably used, and these may be used alone or in combination. From the viewpoint of hardness and oxidative stability, fine particles of copper or copper / nickel alloy or a fired body thereof are particularly suitable.

The conductive layer may have a single layer or a laminated structure.
The method of forming the conductive layer is preferably a wet process, more preferably an inkjet method. This is because fine lines can be easily formed by controlling the application area and application amount of the conductive layer coating liquid. In addition, the thin line formed by the inkjet method has a gradual change in the line width in the thin line cross section from the contact portion with the resin base material to the surface of the conductive layer, so that a transparent conductive film having excellent transparency is obtained. be able to.

(Method for producing transparent conductive film)
The method for producing a transparent conductive film of the present invention forms a resin substrate by a solution casting method using a resin composition containing a cycloolefin resin, an organic polar solvent, an organic nonpolar solvent, and water. In the step of changing the amount of water contained in the resin composition, the amount of metal component, and the drying temperature, the content of the metal component in the surface layer portion of the resin substrate is 1 × 10 ⁻⁶ to 1. The water content per unit area of the surface layer portion of the resin base material when the resin base material was immersed in water was adjusted to be within the range of 10 × ^{3 −3} mass%. It is characterized in that the water content per unit area is adjusted to fall within the range of 120 to 300%.
First, as a method for forming the resin substrate used for the transparent conductive film, known methods such as a melt extrusion method, a solution casting method (solution casting method), a calender method, and a compression molding method can be mentioned.

(Solution casting method)
As the solvent used in the solution casting method, it is preferable to use one or a mixture of alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, and 2-butanol, and with the alcohol solvent, Chlorine solvents such as chloroform and dichloromethane; aromatic solvents such as toluene, xylene, benzene, and mixed solvents thereof; methyl cellosolve, ethyl cellosolve, butyl cellosolve, dimethylformamide, dimethyl sulfoxide, dioxane, cyclohexanone, tetrahydrofuran, acetone, methyl ethyl ketone. (MEK), ethyl acetate, diethyl ether, water and the like may be used in combination.

  As one of the embodiments for forming the transparent conductive film of the present invention by a solution casting method, a step of preparing a resin composition (dope), the dope is cast on a belt-shaped or drum-shaped support. Step, step of drying cast dope as web (first drying step), step of peeling from support, step of further drying peeled web (second drying step), step of stretching, finished resin substrate It is preferable to have a step of winding.

(1) Dope preparing step The dope preparing step is a step of preparing a dope by adding and mixing a cycloolefin resin and a solvent and dissolving them. The dissolution is carried out under normal pressure, below the boiling point of the main solvent, under pressure above the boiling point of the main solvent, JP-A-9-95544, JP-A-9-95557, or JP-A-9-95557. Various melting methods such as the cooling dissolution method described in JP-A-9-95538 and the high pressure method described in JP-A-11-21379 can be used, but the boiling point of the main solvent is particularly preferable. The above method of applying pressure is preferable.

(2) Casting Step In the casting step, the dope prepared in the above dope preparing step is cast from a pressure die slit to a casting position on a metal support such as a stainless belt or a rotating metal drum. It is a process of extending.
In the solution casting method, the concentration of the cyclopolyolefin resin in the dope is preferably the higher the concentration because the drying load after casting on the metal support can be reduced. Load increases, and the filtration accuracy deteriorates. The concentration that satisfies these requirements is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass.
The metal support used in the casting process is preferably a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support. The width of casting can be 1 to 4 m.

(3) First Drying Step In the first drying step, the dope is cast on the casting support, and the formed dope film (hereinafter, also referred to as web) is heated on the casting support. This is a step of evaporating the solvent.
The surface temperature of the support in the casting step is set to -50 ° C or higher and below the temperature at which the web does not boil and foam. A higher temperature is preferable because the drying speed of the web can be increased, but if the temperature is too high, the web may foam or the flatness may be deteriorated.

The preferable support temperature is appropriately determined within the range of 0 to 100 ° C, more preferably within the range of 5 to 30 ° C. Further, it is also a preferable method that the web is gelated by cooling and peeled from the drum in a state of containing a large amount of solvent.
The method of controlling the temperature of the support is not particularly limited, but there are a method of blowing hot air or cold air and a method of bringing hot water into contact with the back side of the support. It is preferable to use warm water because the heat can be efficiently transferred, and thus the time until the temperature of the support becomes constant is short.

  When using hot air, in consideration of the temperature drop of the web due to the latent heat of evaporation of the solvent, while using hot air above the boiling point of the solvent, it may be possible to use air at a temperature higher than the target temperature while also preventing foaming. .. In particular, it is preferable to change the temperature of the support and the temperature of the drying air during the period from casting to peeling to efficiently perform the drying.

(4) Peeling Step The peeling step is a step of peeling the web having the solvent evaporated on the support at the peeling position. The peeled web is sent to the next step.
In order for the resin substrate to exhibit good flatness, the amount of the solvent when peeling the web from the support is preferably in the range of 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. %, Particularly preferably 20 to 30% by mass or 70 to 120% by mass.

The amount of solvent is defined by the following formula.
Solvent amount (mass%) for peeling the web = {(M−N) / N} × 100
In addition, M is the mass of the sample taken at any time during or after the production of the web or film, and N is the mass of M after heating M at 115 ° C. for 1 hour.

(5) Second Drying Step The second drying step is a step of further evaporating the solvent contained in the web separated from the support. In the present invention, the web that has undergone the second drying step is referred to as a resin base material.
In the second drying step, the web is conveyed by a general roll drying method (a method in which the web is alternately passed through a large number of rolls arranged above and below to dry) or a tenter method described in JP 2012-13824A. The method of drying is adopted.

When the tenter is performed, the drying temperature is preferably within the range of 30 to 180 ° C, more preferably within the range of 50 to 170 ° C.
The thickness of the resin base material (after drying) of the present invention varies depending on the purpose of use, but is usually in the range of 5 to 500 μm, preferably in the range of 10 to 150 μm, and considering the thinning of the device, 100 μm. The following is particularly preferable.

(6) Stretching Step The stretching step is a step of stretching the produced resin substrate.
The resin base material used in the present embodiment may be an unstretched base material or a stretched base material, but a stretched base material is preferable from the viewpoint of improving strength and suppressing thermal expansion. The stretching method is not particularly limited.
For example, a method in which the peripheral speed difference is applied to a plurality of rolls and the roll peripheral speed difference between them is used to stretch in the longitudinal direction, both ends of the web are fixed with clips or pins, and the interval between the clips or pins is widened in the traveling direction. And a stretching method in the longitudinal direction, a method of stretching in the lateral direction and stretching in the lateral direction, a method of simultaneously stretching in the longitudinal and lateral directions and stretching in both the longitudinal and lateral directions, and oblique stretching.

  For these methods, a plurality of methods may be used in combination, and the stretching operation may be performed in multiple stages. That is, it may be stretched in the transverse direction with respect to the film forming direction, in the longitudinal direction, or in both directions. When it is further stretched in both directions, it may be simultaneous stretching or sequential stretching. May be. Further, it may be performed at the same time as the above-mentioned second drying step. By dividing into several times, it is possible to more uniformly stretch even in high-strength stretching. Before the oblique stretching, the stretching may be performed in the width or length so as to prevent the shrinkage in the width direction.

The in-plane retardation value Ro at the measurement wavelength of 589 nm of the resin substrate according to the present invention is preferably in the range of 0 to 150 nm. More preferably, Ro is in the range of 0 to 20 nm or 40 to 150 nm.
The retardation value Rt in the thickness direction at the measurement wavelength of 589 nm is preferably in the range of 0 to 400 nm, and particularly preferably Rt is in the range of 0 to 70 nm or Rt is in the range of 80 to 300 nm. By setting Rt in the preferable range, the visibility when used for a polarizing plate is improved.

Formula _{(i) Ro = (n x} -n y) × d
Formula (ii) Rt = ((n _x + n _y ) / 2−n _z ) × d
In the formula, Ro is the retardation value in the film plane, Rt is the retardation value in the thickness direction, n _x is the refractive index in the slow axis direction in the film plane, and n _y is the refractive index in the fast axis direction in the film plane. , _Nz represents the refractive index in the thickness direction of the film, and d represents the film thickness (nm).
In the present invention, the in-plane retardation value Ro and the thickness direction retardation value Rt at the measurement wavelength of 589 nm are the phase difference measurement device “KOBRA-WPR” (Oji measurement instrument ( Co., Ltd.).
The retardation value of the resin base material can be controlled by selection of the resin material, stretching ratio during film formation, and the like. Specifically, it can be controlled to an arbitrary value by appropriately selecting the stretching ratio in the machine direction and the transverse direction.

(7) Winding Step The winding step is a step of winding the resin base material formed through the above steps into a long roll shape. As a winding method, a generally used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like, and these may be used properly.
Before winding, the ends may be slit to have a product width and cut off, and knurling (embossing) may be applied to both ends to prevent sticking and scratches during winding. As the knurling method, a metal ring having an uneven pattern on its side surface can be processed by heating or pressing.

The resin base material according to the present invention achieves desired optical properties by appropriately adjusting process conditions such as the structure of the cycloolefin resin used, the type and amount of additives, the draw ratio, and the amount of solvent during peeling. You can For example, the retardation Rt in the thickness direction can be widely controlled within the range of 180 to 300 nm by adjusting the amount of the solvent at the time of peeling within the range of 40 to 85% by mass.
Generally, the larger the amount of solvent at the time of peeling, the smaller the Rt, and the smaller the amount of solvent at the time of peeling, the larger the Rt. For example, by shortening the drying time on a metal endless support and increasing the amount of solvent at the time of peeling, the surface orientation can be relaxed and Rt can be lowered, and the process conditions can be adjusted. It is possible to express various retardations according to various uses.

  In the present invention, since the conductive layer is formed on the resin substrate, the surface energy of the resin substrate is preferably 40 mN / m or more. When the surface energy of the resin base material is less than 40 mN / m, the contact angle of the conductive material liquid with respect to the resin base material tends to be high, and the difference in the evaporation amount between the liquid middle layer portion and the edge is small, so that the conductivity is improved. Convection from the middle part of the material droplet to the edge is not promoted. It is possible to change the composition of the conductive material liquid so as to reduce the contact angle, but this is not preferable from the viewpoint of flexibility in selecting the composition type. On the other hand, when the surface energy is 40 mN / m or more, the contact angle of the conductive material liquid with respect to the resin base material tends to be low, and the difference in the evaporation amount between the liquid middle layer portion and the edge becomes large, so that the conductive material liquid Convection from the middle part of the drop to the edge is promoted. As a result, the thinning of the parallel lines of the conductive layer is promoted, and the effect of further increasing the transparency can be obtained. It is also preferable from the viewpoint of flexibility in selecting the composition type.

  The surface energy referred to in the present invention is a value representing the wettability of the surface of the base material measured by the contact angle method using water and diiodomethane as standard solutions. Specifically, by using DM-500 manufactured by Kyowa Interface Science Co., Ltd., the contact angle between ultrapure water and diiodomethane can be measured, and the surface energy in a binary system can be calculated and obtained.

It is preferable to form a conductive layer on the resin substrate formed by the above steps.
Various methods can be used to form the conductive layer, but a wet process is preferable, and an inkjet method is more preferable. Specifically, as a method for forming the conductive layer, a method of forming a parallel line pattern by an inkjet method can be mentioned, and for example, the method described in JP-A-2014-120353 can be used.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, “parts” or “%” is used, but unless otherwise specified, “parts by mass” or “% by mass” is indicated. Regarding the water content, the above-mentioned water content measuring method is used, and the “surface layer water content / middle layer water content” represents a ratio (%) per unit area.

<< Preparation of transparent conductive film 1 >>
(Preparation of dope)
Then, the following compositions were mixed to prepare a dope (cycloolefin resin composition).
Cycloolefin polymer ("Arton (registered trademark) G7810" manufactured by JSR Co.) 150 parts by mass Dichloromethane 380 parts by mass Methanol 70 parts by mass Distilled water 5 parts by mass Metal nanoparticles (Ag: average particle size 20 nm Ag nano manufactured by DOWA Electronics Co., Ltd.) Powder-1) 0.005 parts by mass

The dope prepared above was uniformly cast (cast) on a stainless belt support at a temperature of 33 ° C. and a width of 2000 mm using an endless belt casting device. Next, the solvent in the dope is peeled off in a state of about 20% by mass, both ends in the width direction of the film are held by tenters, and the amount of solvent is 10% by mass, and the width direction is 1 at a temperature of 115 ° C. It was dried while being stretched 0.05 times (5%).
Then, it was further dried by transporting it between rolls of a heat treatment apparatus at 100 ° C. for 30 minutes to produce a resin base material.

(Preparation of coating liquid 1 for conductive layer)
Metal nanoparticles (Ag: average particle diameter 20 nm, DO Nano Electronics Co., Ltd. Ag nanopowder-1) 0.8 parts by mass Surfactant (silicon BYK BYK Chemie Japan Co., Ltd. BYK348) 0.01 parts by mass 1,3- Butadiene 25 parts by mass Water 75 parts by mass

(Formation of conductive layer)
The resin base material obtained above was cut into 200 mm square, and a lattice pattern composed of fine lines was formed in the 190 mm square area on the resin base material by the following procedure using an inkjet method.
First, using a printer equipped with an inkjet head (“KM512L” manufactured by Konica Minolta Co., Ltd. (droplet volume 42 pl)) filled with the coating liquid 1 for a conductive layer as an ink for forming a fine line, a 200 μm pitch was formed on the film. Then, a plurality of lines were formed in a stripe shape.
In each of the plurality of lines, the metal nanoparticles (Ag) contained therein are accumulated at the widthwise end portions of each line during the drying process, and as a result, one line is divided into two parallel lines. It became a line.

Next, the film was rotated by 90 °, and a plurality of lines were drawn so as to be orthogonal to the previously formed line. Similar to the previously formed line, the plurality of lines also became two parallel lines during the drying process.
The line thus formed was baked at 100 ° C. for 1 hour to form a grid pattern in which the lines were arranged at 100 μm intervals, and a transparent conductive film 1 was obtained.
The line width of each thin line forming the lattice pattern was 5 μm, and the thickness was 0.02 μm.

<< Preparation of transparent conductive films 2 to 19 >>
The transparent conductive films 2 to 19 were manufactured in the same manner as the transparent conductive film 1 except that the ratio of the materials used to manufacture the transparent conductive film 1 was changed to the materials shown in Table 1.

<< Evaluation of transparent conductive film >>
<Adhesion>
With respect to the formed 10 mm × 10 mm metal pattern, adhesion was evaluated by a tape peeling test in accordance with the description of JIS K5600. Specifically, notches of vertical and horizontal 25 square lattice patterns at intervals of 2 mm were formed by a cutter, and cellophane tape was attached on the lattice patterns. When this tape was peeled off, the number of pieces peeled off to the tape side was counted, and the adhesion was evaluated according to the following evaluation ranks.

⊚: No peeled metal pattern is recognized ◯: Peeled metal pattern is recognized, but the number of occurrence is less than 5.0% △: Peeled metal pattern is recognized, but the number of occurrence is 5.0% or more Less than 10% x: A peeled metal pattern is recognized, and the number of occurrence is 10% or more.

<Conductivity>
The four-probe probe PSP of a resistivity meter Loresta GP (manufactured by Dia Instruments Co., Ltd.) was connected to the metal pattern of the above-prepared wiring to measure the conductivity, and the conductivity was evaluated according to the following evaluation ranks.

⊚: Conductivity is less than 5.0 μΩ · cm ◯: Conductivity is 5.0 μΩ · cm or more and less than 10 μΩ · cm Δ: Conductivity is 10 μΩ · cm or more and less than 20 μΩ · cm ×: Conductivity The rate is 20 μΩ · cm or more

<Light transmittance>
The initial transparency of the transparent conductive film was measured by measuring the average light transmittance at a measurement wavelength of 400 to 800 nm using a spectrophotometer "U4100" (manufactured by Hitachi High-Tech).
Assuming that this measurement is applied to a transmission capacitive touch panel, a transparent conductive film consisting of a support, a high refractive index layer, a sulfuration preventing layer and a transparent conductive layer is used to reflect the actual system. Was evaluated by measuring the above-mentioned total light transmittance by affixing it to a glass substrate with an immersion oil "type A (n = 1.515)" (manufactured by Nikon Corporation) used in an oil immersion optical system.
The average light transmittance was measured by making light incident from an angle inclined by 5 ° with respect to the normal line of the surface of the transparent conductive film on the transparent resin support side.

⊚: Average light transmittance of 92% or more ◯: Average light transmittance of 90% or more and less than 92% Δ: Average light transmittance of 85% or more and less than 90% ×: Average light transmittance of 85 Less than% Evaluation was performed as described above.

<Noise>
A touch panel was made with the obtained conductive film, and when the panel was touched with an impedance analyzer, the peak intensity and half width of the output waveform when a rectangular wave with a frequency of 1 MHz was input were measured, and the following formula was used. Ranking was performed based on the obtained S (output or input).
S (output or input) = (peak intensity) x (half width)
◯: S (output) is 95% or more of S (input) Δ: S (output) is 90% or more of S (input) X: S (output) is less than 90% of S (input) Adhesion In terms of conductivity, light transmittance, and noise, a rank of ◯ or ⊚ was evaluated to be in a practically good range. Table 1 shows each evaluation result obtained as described above.

If the water content per unit volume of the surface layer portion on one surface of the resin substrate when immersed in water is within the range of 120 to 300% with respect to the water content per unit volume of the middle layer portion of the resin substrate. Since the ink easily penetrates into the surface layer of the film and the adhesiveness with the resin base material is obtained, the conductive performance is improved. On the other hand, if the water content is too high, it is considered that the ink deeply penetrates into the resin base material and reduces the conductivity of the surface layer portion.
In addition, since the amount of metal in the surface layer of the resin base material contributes to the adhesiveness with the conductive layer, the larger the amount of metal, the higher the conductivity performance. On the other hand, if the amount of metal in the resin base material is too large, the adhesion to the base material is high, but it is considered that the electric conductivity is deteriorated because the current diffuses into the base material when electricity is applied.

Similarly, regarding noise, it is considered that the amount of metal in the surface layer of the resin base material contributes to the adhesion to the conductive layer.
If the adhesiveness to the base material is not good, scattering and reflection will be strong at the interface between the base material layer and the conductive layer, and the light transmittance will decrease. Specifically, if the adhesion is poor, the interface between the base material and the conductive layer is not completely adhered, so there are minute voids, which is considered to be a factor that greatly reduces transparency. Be done. Therefore, by adjusting the metal component of the surface layer portion of the resin base material within the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%, it is possible to fill the minute voids and improve the adhesiveness. did it.

  According to the present invention, it is possible to obtain a transparent conductive film having excellent adhesion between a conductive layer and a resin substrate, and having good conductivity and transparency, a liquid crystal display, a plasma display, an inorganic and organic EL display, a touch panel, It can be suitably used for various display devices such as solar cells.

1 Transparent Conductive Film 2 Resin Substrate 3 Surface Layer 4 Conductive Layer 5 Middle Layer

Claims (5)

A transparent conductive film having a resin substrate and a conductive layer,
The main component of the resin base material is a cycloolefin resin,
The surface layer portion of the resin base material contains a metal component in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%, and
When the resin base material is immersed in water, the water content per unit volume of the surface layer portion of the resin base material is in the range of 120 to 300% with respect to the water content per unit volume of the middle layer portion of the resin base material. A transparent conductive film, characterized in that it is adjusted to be inside.   The transparent conductive film according to claim 1, wherein the metal component contains any one of gold, silver, copper, iron, aluminum, nickel, magnesium, zinc and alloys thereof.   The said electroconductive layer is a metal electroconductive layer, The transparent electroconductive film of Claim 1 or Claim 2 characterized by the above-mentioned. A method for producing a transparent conductive film for producing a transparent conductive film having a resin substrate and a conductive layer ,
A cycloolefin resin, and an organic polar solvent, in the step of forming the organic non-polar solvent, a resin substrate by using a resin composition containing a water solution casting method, included in the resin composition By changing the amount of water, the amount of metal component, and the drying temperature, the content of the metal component in the surface layer portion of the resin base material becomes within the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mass%. And when the resin base material is immersed in water, the water content per unit volume of the surface layer portion of the resin base material is 120 with respect to the water content per unit volume of the middle layer portion of the resin base material. The method for producing a transparent conductive film is characterized in that it is adjusted to fall within the range of 300%.   The method for producing a transparent conductive film according to claim 4, wherein the conductive layer is formed by an inkjet method.

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