JP6553451B2 - Transparent resin film, transparent conductive film, and touch panel using the same - Google Patents

Description

  The present invention relates to a transparent resin film having a cured resin layer on at least one surface side of a substrate film, a transparent conductive film, and a touch panel using the same, and is a technique useful for preventing waviness due to shrinkage particularly when heated.

  In the field of touch panels and the like, in recent years, it has been increasingly required to reduce the thickness thereof, and along with this, it is also demanded to reduce the thickness of the transparent conductive film itself. As a general touch panel system, a resistive film system, a capacitive system, and the like can be given. In the case of the resistive film method, the durability of the pen is required due to the basic structure of the conductive method, so that it is difficult to reduce the thickness of the transparent conductive film. On the other hand, in the case of the electrostatic capacitance system, which has recently come to be widely adopted in touch panels, position detection is performed using a change in electrostatic capacitance, so the thickness of the transparent conductive film itself can be reduced. And the demand from the market is strong.

  However, when the transparent conductive film is thinned, the transparent conductive film itself is susceptible to the heat shrinkage behavior. In such a case, even when the surface protective film is laminated, when etching is performed to form a transparent conductive film in the manufacturing process of the touch panel, it may be caused by immersion in a resist solution or a developer or heating during drying, etc. Irregular waviness occurs in the transparent conductive film. When the transparent conductive film in which such a waviness generate | occur | produced is used for an actual product, the transparent conductive film pattern becomes easy to be seen in the lighting or light extinction state of a display, and the problem of pattern visibility will arise.

  On the other hand, in Patent Document 1, stress generated at the interface between the transparent conductor layer and the substrate by reducing the difference in dimensional change between the pattern forming portion and the pattern opening when the transparent conductive film is heated. Therefore, it is described that the film is less likely to be undulated and the pattern of the transparent conductor layer is difficult to be visually recognized. However, controlling the dimensional change rate limits the films that can be used, and there is room for further improvement.

Japanese Patent Application Laid-Open No. 2013-043372

  Therefore, the object of the present invention is to prevent occurrence of waviness caused by the difference in thermal contraction rate between the transparent conductive film pattern portion and the etching portion even if the heat history accompanying patterning of the transparent conductive film is obtained, and it is preferable It is an object of the present invention to provide a transparent resin film having high transparency, a transparent conductive film, and a touch panel using the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by adopting the following configuration, and have arrived at the present invention.

  That is, the transparent resin film of the present invention is a transparent resin film having a cured resin layer on at least one surface side of a substrate film, and the thickness of the cured resin layer is 0.5 μm to 10 μm, The resin layer contains a resin and inorganic particles, and the inorganic particles contain small particles with a particle size of 10 nm to 60 nm and large particles with a particle size of more than 60 nm and 500 nm or less, and the small particles are the cured resin The layer contains 25 to 74% by weight, the large particles are contained in the cured resin layer in an amount of 1 to 30% by weight, and the total of the large particles and the small particles is in the cured resin layer. The transparent resin film is contained in an amount of 46 to 75% by weight. In addition, the various physical-property values in this invention are values measured by the method employ | adopted in an Example etc.

  In a transparent conductive film in which a cured resin layer and a transparent conductive film are laminated in this order on a substrate film, when patterning the transparent conductive film, the transparent conductive film is immersed in an etching solution or the like and heated and dried. As a result, unevenness occurs in the conductive film, and undulation occurs. The undulation is caused by the difference in thermal contraction rate between the transparent conductive film patterning portion and the etching portion. This undulation is a phenomenon that occurs when the transparent conductive film is not patterned but occurs when it is patterned. That is, since the transparent conductive film patterning part has a base film on the lower side, it is hard to move even if it receives heat, and the transparent conductive film etching part becomes easy to move because there is no transparent conductive film that restricts movement. Because of this, swell occurs. As a result of carrying out studies to adjust the particle size and content of the inorganic particles in the cured resin layer, shrinkage of the cured resin layer is suppressed by containing the inorganic particles of the particle size and content in the above range, and the heat shrinkage is reduced. It became possible to suppress the occurrence of swell. Although this mechanism is not clear, it is considered as follows. By increasing the content of the inorganic particles contained in the cured resin layer, the content of the resin is reduced, and it is considered that thermal contraction due to the resin can be suppressed. In order to increase the content of the inorganic particles, large particles having a large particle size and small particles having a small particle size are combined, and packing can be performed in a high density state. Furthermore, by using many small particles having a small particle size at the nano level, large particles having large particle sizes are reduced, and it is considered possible to simultaneously suppress haze.

  It is preferable that the thermal shrinkage rate in the MD direction (flow direction) when the transparent resin film of the present invention is heated at 140 ° C. for 90 minutes is 0.45% or less. When the heat shrinkage ratio is within the above range, the heat shrinkage during heating of the etched transparent conductive film can be suppressed, so that the waviness can be suppressed, and thus the pattern appearance due to the waviness can be prevented. Visibility can be achieved.

  In the transparent resin film of the present invention, it is preferable that a ratio obtained by dividing the content of the large particles by the content of the small particles is 0.05 to 0.75. Thereby, the thermal contraction at the time of heating of the transparent conductive film subjected to the etching process can be suppressed, and the occurrence of waviness can be suppressed, and the visibility of a display device such as a touch panel can be improved.

  In the transparent resin film of the present invention, the haze of the cured resin layer of the transparent resin film is preferably less than 0.3%. Thereby, while being able to manufacture the transparent conductive film excellent in an external appearance quality, when used for a touch panel etc., the visibility of a display apparatus etc. can be improved.

  It is preferable that the thermal contraction rates in the MD direction and the TD direction (width direction) when the transparent resin film of the present invention is heated at 140 ° C. for 90 minutes are all 0.4% or less. Thereby, the thermal contraction at the time of heating of the etched transparent conductive film can be suppressed, and the waviness can be suppressed at a higher level, and consequently, the pattern appearance caused by the waviness can be prevented and good visibility can be achieved. .

  As for the transparent conductive film of this invention, it is preferable that the transparent conductive film is formed in the at least one surface side of the said base film. By forming a transparent conductive film on the transparent conductive film of the present invention, a transparent conductive film in which the occurrence of swell is suppressed is obtained.

  The transparent conductive film of the present invention preferably further includes one or more optical adjustment layers between the transparent resin film and the transparent conductive film. Since the refractive index can be controlled by the optical adjustment layer, the difference in reflectance between the pattern formation portion and the pattern opening can be reduced, the transparent conductive film pattern is hard to see, and the visibility is improved in a display device such as a touch panel. .

  The touch panel of the present invention preferably includes the transparent conductive film. According to the transparent conductive film, heat shrinkage at the time of heating of the etched transparent conductive film can be suppressed, and therefore, it becomes difficult to cause waviness, and the transparent conductive film pattern is hardly visible and the visibility becomes good.

It is a typical sectional view of a transparent resin film concerning one embodiment of the present invention. It is typical sectional drawing of the transparent conductive film which concerns on one Embodiment of this invention.

  Embodiments of the transparent resin film and the transparent conductive film of the present invention will be described below with reference to the drawings. However, in some or all of the drawings, parts unnecessary for the description are omitted, and there are parts shown enlarged or reduced for easy explanation. The terms indicating the positional relationship such as up and down are merely used for ease of explanation, and are not intended to limit the configuration of the present invention.

<Transparent conductive film>
FIG. 1 is a schematic cross-sectional view of a transparent resin film according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a transparent conductive film according to an embodiment of the present invention. As shown in FIG. 1, the transparent resin film of the present invention includes a base film 1 and a cured resin layer 2. The cured resin layer 2 includes a resin 3 and inorganic particles 4. The inorganic particles 4 include small particles 41 and large particles 42. As shown in FIG. 2, in the transparent conductive film of the present invention, the transparent conductive film 5 is formed on at least one surface of the transparent resin film, and the transparent conductive film 5 is formed on the cured resin layer 2. May be In FIG. 1, although the cured resin layer 2 is formed only on one side of the base film 1, the cured resin layer 2 may be formed on both sides of the base film 1. Further, in FIG. 2, although the cured resin layer 2 and the transparent conductive film 5 are formed only on one surface side of the substrate film 1, the cured resin layer 2 and the transparent conductive film 5 are formed on both surfaces of the substrate film 1. May be formed.

(Base film)
The base film is not particularly limited as long as it is transparent in the visible light region, and various plastic films having transparency are used. For example, as a material of a plastic film, polyester resin, acetate resin, polyether sulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, cycloolefin resin, (meth) acrylic resin Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin and the like can be mentioned. Among these, polyester resins, polycarbonate resins and polyolefin resins are particularly preferable.

  The surface of the substrate film is subjected to an etching treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical formation, oxidation, or undercoating beforehand, and a cured resin layer or a transparent layer formed on the substrate film You may make it improve adhesiveness with an electrically conductive film. Moreover, before forming a cured resin layer and a transparent conductive film, you may remove and clean the base film surface by solvent washing | cleaning, ultrasonic cleaning, etc. as needed.

  The thickness of the base film is preferably in the range of 2 to 200 μm, and more preferably in the range of 10 to 100 μm. Within this range, the mechanical strength of the substrate film is sufficient, and the scratch resistance and the dot characteristics for touch panels can be improved. In addition, it is possible to make the film into a roll to continuously form a transparent conductive film or the like.

  Although the heat shrinkage rate of the resin film raw fabric (film before heat treatment etc. before laminating a cured resin layer) which forms a base film is not particularly limited, it is particularly preferable to use MD as a resin film raw fabric. It is preferable to use a polyester-based resin film having a heat shrinkage rate in the direction of 1.2% or less and a heat shrinkage rate in the TD direction of -0.2 to 0.6%. It is more preferable to use a polyester resin film that is 0.9% or less and that has a thermal shrinkage in the TD direction of -0.15 to 0.5%. It is further preferable to use a polyethylene terephthalate film having the thermal shrinkage in the MD direction and the thermal shrinkage in the TD direction within the above range. Thereby, it becomes a carrier film excellent in toughness, workability, and transparency, workability is improved, and generation of undulation can be suppressed.

  Moreover, although it has a cured resin layer in the at least one surface side of a base film, undercoat layers, such as an optical adjustment layer and an antiblocking layer, may be formed in the transparent conductive film formation surface side. An undercoat layer such as an easy-adhesion layer or an anti-blocking layer may be provided on the surface of the base film opposite to the surface on which the transparent conductive film is formed, if necessary. In addition, a protective layer such as a separator is temporarily attached to an adhesive layer or the like to which another substrate is attached using an appropriate adhesive means such as an adhesive, or to an adhesive layer or the like for attaching to another substrate It may be.

(Cured resin layer)
The cured resin layer is formed on at least one surface side of the base film. As a result, control of the reflection characteristics and adhesion with the transparent conductive film can be improved, and the base film is scratched in each process such as formation and patterning of the transparent conductive film or mounting on an electronic device. Can be prevented.

  The cured resin layer includes a resin and inorganic particles. The resin material has sufficient strength as a film after the formation of a cured resin layer, and a material having transparency can be used without particular limitation. Examples of the resin to be used include thermosetting resins, thermoplastic resins, ultraviolet curable resins, electron beam curable resins, two-component mixed resins, etc. Among them, curing treatment by ultraviolet irradiation is simple. An ultraviolet curable resin capable of efficiently forming a cured resin layer by a simple processing operation is preferable.

  Examples of UV curable resins include various resins such as polyester resins, acrylic resins, urethane resins, amide resins, silicone resins and epoxy resins, and UV curable monomers, oligomers, polymers, etc. included. As an ultraviolet curable resin used preferably, acrylic resin and an epoxy resin are preferable, More preferably, it is acrylic resin.

  Various additives can be added to the resin as necessary. Examples of such additives include conventional additives such as fine particles, leveling agents, photopolymerization initiators, antistatic agents, plasticizers, surfactants, antioxidants, and ultraviolet absorbers.

  The photopolymerization initiator is not particularly limited as long as it is a substance that generates radicals or cations by irradiation with ultraviolet light of an appropriate wavelength that can be a trigger of the polymerization reaction, depending on the type of radiation-reactive component. Examples of the photopolymerization initiator include alkylphenone-based, benzoin-based, benzophenone-based and acylphosphine oxide-based photopolymerization initiators. From the viewpoint of heat resistance, alkylphenone-based photopolymerization initiators are preferable. The content of the photopolymerization initiator is usually 0.1 to 10 parts by weight and preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the resin.

  Examples of the leveling agent include acrylic, fluorine, and silicone leveling agents, and silicone leveling agents are preferable. Examples of silicone-based leveling agents include reactive silicones, polydimethylsiloxanes, polyether-modified polydimethylsiloxanes, polymethylalkylsiloxanes, and the like. Of these, reactive silicone is preferable. When reactive silicone is added, slipping property is imparted to the surface of the cured resin layer, and scratch resistance is maintained over a long period of time. The content of the leveling agent is usually preferably 5 parts by weight or less, more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the resin.

  The cured resin layer preferably contains inorganic particles from the viewpoint of preventing undulation. The inorganic particles preferably include at least large particles and small particles. Examples of the inorganic particles include silicon oxide (silica particles) particles, hollow nanosilica particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, zirconium oxide particles and the like. Among these, silicon oxide (silica particles) particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, and zirconium oxide particles are preferable. In particular, from the viewpoint of refractive index, silicon oxide (silica particle) particles are preferable. One of these may be used alone, or two or more may be used in combination.

  The particle diameter of the small particles is preferably in the range of 10 nm to 60 nm, more preferably in the range of 15 nm to 55 nm, and still more preferably in the range of 20 nm to 50 nm from the viewpoint of preventing generation of waviness and suppressing the haze. In addition, it is preferable that a "particle size" is the mode particle size (The particle size which shows the maximum value of particle size distribution).

  The large particle diameter is preferably in the range of more than 60 nm and 500 nm or less, more preferably in the range of 80 nm to 450 nm, and still more preferably in the range of 100 nm to 400 nm from the viewpoint of packing in a high density state to prevent waviness. .

  The small particles are preferably contained in an amount of 25 to 74% by weight, more preferably 30 to 70% by weight, in the cured resin layer, from the viewpoint of preventing generation of waviness and suppressing haze. More preferably, it is contained by weight.

  The large particles are preferably contained in the cured resin layer in an amount of 1 to 30% by weight, more preferably 3 to 27% by weight, from the viewpoint of packing in a high density state to prevent waviness. More preferably, it is contained in an amount of ˜25% by weight.

  The total of the small particles and the large particles reduces the difference in thermal shrinkage between the transparent conductive film pattern portion and the etched portion when patterning the transparent conductive film, and from the viewpoint of preventing waviness and suppressing the haze, the cured resin The layer preferably contains 46 to 75% by weight, more preferably 50 to 74% by weight, and still more preferably 52 to 73% by weight.

  The ratio obtained by dividing the content of the large particles by the content of the small particles is preferably in the range of 0.05 to 0.75 from the viewpoint of reducing haze and packing in a high density state, and is 0.07 to 0. The range of .67 is more preferable, and the range of 0.08 to 0.50 is still more preferable.

  When the cured resin layer is a resin composition containing a curable resin and, if necessary, a leveling agent, a photopolymerization initiator, inorganic particles, etc. on the base film, and the resin composition contains a solvent, The solvent can be dried and cured by heat, active energy rays or the like. The heat may be known means such as an air circulation oven or an IR heater, but is not limited to these methods. Examples of the active energy ray include ultraviolet rays, electron beams, gamma rays and the like, but are not particularly limited.

  The cured resin layer can be formed into a film by the wet coating method (coating method) etc. using said material. For example, in the case of forming indium oxide (ITO) containing tin oxide as the transparent conductive film, the crystallization time of the transparent conductive film can be shortened if the surface of the cured resin layer which is the base layer is smooth. From this point of view, the cured resin layer is preferably formed by a wet coating method.

  The thickness of the cured resin layer is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 7 μm, and most preferably 0.5 μm to 5 μm. When the thickness of the cured resin layer is in the above range, precipitation of low molecular weight components such as oligomers from a plastic film can be suppressed, and deterioration in visibility of a touch panel or the like can be prevented. In addition, it is possible to suppress swells and curls generated by heating during crystallization of the transparent conductive film and assembly of the touch panel.

  When the cured resin layer is formed on the base film, the heat shrinkage ratio in the MD direction when the transparent resin film is heated at 140 ° C. for 90 minutes is 0.45% or less from the viewpoint of suppressing the waviness. Is preferably 0.40% or less, and more preferably 0.35% or less. The lower limit value of the thermal contraction rate in the MD direction is not particularly limited, but is preferably 0% or more. The thermal shrinkage in the TD direction is preferably 0.40% or less, more preferably 0.20% or less, and still more preferably 0.10% or less. The lower limit value of the thermal shrinkage rate in the TD direction is not particularly limited, but is preferably -0.10% or more. Further, from the viewpoint of suppressing the occurrence of waviness and improving the pattern visibility, it is preferable that the heat shrinkage rate in the MD direction and the heat shrinkage rate in the TD direction are both 0.4% or less, 0.2% It is more preferable that

  The haze of the cured resin layer of the transparent resin film of the present invention is preferably less than 0.3%, more preferably 0.2% or less, and still more preferably 0.1% or less. When the haze of the transparent resin film is high, when used in a touch panel or the like, the clarity of the image is reduced due to light scattering, which tends to cause character blurring of the display screen and the like.

The cured resin layer can contain other inorganic substances. The inorganic _{material, NaF (1.3), Na 3} AlF 6 (1.35), LiF (1.36), MgF 2 (1.38), CaF 2 (1.4), BaF 2 (1.3 ), LaF ₃ (1.55), CeF (1.63), etc. (the numerical values in parentheses indicate the refractive index).

(Optical adjustment layer)
It is preferable that one or more optical adjustment layers be formed between the transparent resin film and the transparent conductive film. The optical adjustment layer reduces the reflectance difference between the two by adjusting the optical thickness difference between the pattern forming portion where the transparent conductive film is formed and the pattern opening where the transparent conductive film is removed. It is provided for the purpose of making it difficult to be visually recognized.

The optical adjustment layer can be formed of an inorganic substance, an organic substance, or a mixture of an inorganic substance and an organic substance. For example, as inorganic substances, NaF (1.3), Na ₃ AlF ₆ (1.35), LiF (1.36), MgF ₂ (1.38), CaF ₂ (1.4), BaF ₂ (1. 3), inorganic substances such as SiO ₂ (1.46), LaF ₃ (1.55), CeF ₃ (1.63), Al ₂ O ₃ (1.63) It is a rate]. Among these, SiO ₂ , MgF ₂ , Al ₂ O _{3 and the} like are preferably used. In particular, SiO ₂ is preferred.

  Examples of the organic substance include acrylic resins, urethane resins, melamine resins, alkyd resins, siloxane polymers, organic silane condensates and the like. At least one of these organic substances is used. In particular, as the organic substance, it is desirable to use a thermosetting resin made of a mixture of a melamine resin, an alkyd resin, and an organosilane condensate.

  The formed optical adjustment layer can be formed by a vacuum evaporation method, a sputtering method, a dry process such as an ion plating method, or a wet coating method (coating method).

  The refractive index of the optical adjustment layer is preferably such that the difference with the refractive index of the transparent conductive film is 0.1 or more. The difference between the refractive index of the transparent conductor layer and the refractive index of the optical interference layer is preferably 0.1 or more and 0.9 or less, and more preferably 0.1 or more and 0.6 or less. In addition, it is preferable that the refractive index of an optical interference layer is 1.3-2.5 normally, Furthermore, 1.38-2.3, Furthermore, it is preferable that it is 1.4-2.3. By controlling the refractive index of the optical adjustment layer as described above, the difference in reflectance between the pattern forming portion and the pattern opening can be reduced.

  The thickness of the optical adjustment layer is not particularly limited, but is usually about 1 to 300 nm, preferably 5 to 300 nm, in terms of optical design and the effect of preventing generation of oligomers from the transparent resin film. When the optical adjustment layer is composed of two or more layers, the thickness of each layer is preferably about 5 to 250 nm, and more preferably 10 to 250 nm.

  Such an optical adjusting layer can be provided directly on the substrate film, or may be provided on the cured resin layer as described above. An optical adjustment layer can also contribute to suppression of the heating dimensional change of a transparent resin film similarly to said cured resin layer. However, since the thickness of the optical adjustment layer is generally smaller than that of the cured resin layer, the cured resin layer is superior in the effect of suppressing changes in heating dimensions. Therefore, by providing a cured resin layer on the base film and providing an optical adjustment layer thereon, the reflectance difference between the pattern forming portion and the pattern opening is suppressed while suppressing the dimensional change of the transparent resin film. It can also be suppressed.

(Transparent conductive film)
The transparent conductive film is a film on which at least one layer of a transparent conductive film is formed, and may have two or more layers of transparent conductive films. The transparent conductive film is a thin film containing a conductive oxide of metal as a main component, or a thin film containing a composite metal oxide containing a main metal and one or more impurity metals as a main component. The constituent materials of these conductive thin films are not particularly limited as long as they are transparent and have conductivity. Sc, Y, Si, Zr, Hf, V, Nb, Ta, Cr, Mo, W , Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Zn, Cd, Al, Mg, Ga, Ti, Ge, In, Sn, Pb Preferably, a metal oxide composed mainly of one metal selected from the group consisting of As, Sb, Bi, Se, Te and I is used. From the viewpoint of transparency and conductivity of the transparent conductive film, the main metal element is preferably any of In, Zn, and Sn, and an indium-based composite oxide is most preferable. When the transparent conductive film is a composite metal oxide containing a main metal and an impurity metal, one or more metals selected from the above group are preferably used as the impurity metal.

  From the viewpoint of increasing the carrier density of the transparent conductive film to lower the resistance of the transparent conductive film, the impurity metal in the composite metal oxide is preferably one having a higher valence electron number than the main metal. As such a composite metal oxide, indium tin complex oxide (ITO), antimony-doped tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO) Etc.). Among them, indium-tin complex oxide is most preferably used in view of forming a transparent conductive film having low resistance and high transparency. Such an indium-tin composite oxide is characterized by high transmittance in the visible light region (380 nm to 780 nm) and low surface resistance per unit area.

  The formation method of a transparent conductive film is not specifically limited, A conventionally well-known method is employable. Specifically, for example, a vacuum deposition method, a sputtering method, and an ion plating method can be exemplified. In addition, an appropriate method can be adopted depending on the required film thickness.

  Each transparent conductive film may be crystalline or amorphous. For example, in the case where a plastic film is used as a transparent substrate and an ITO film is formed as a transparent conductive film by sputtering, there is a restriction due to the heat resistance of the substrate, and sputter film formation can not be performed at high temperatures. For this reason, the transparent conductive film immediately after film formation is often an amorphous film (some of which may be crystallized). Such an amorphous transparent conductive film has a low transmittance as compared with a crystalline one, and may cause problems such as a large change in resistance after a heat and humidity test. From such a point of view, once an amorphous transparent conductive film is formed, it may be converted to a crystal film by heating in the presence of oxygen in the atmosphere. By crystallizing the transparent conductive film, the transparency is improved and the resistance can be lowered, and further, the resistance change after the humidification heat test is small, and the humidification heat reliability is improved.

  The surface resistance value of the indium-tin composite oxide layer is preferably 300Ω / □ or less, and more preferably 270Ω / □ or less. Such a transparent conductive film having a small surface resistance value is formed, for example, after forming an amorphous layer of an indium-tin-based composite oxide on a cured resin layer by sputtering or vacuum evaporation, and then at 120 ° C. to 200 ° C. It heat-processes for about 30 to 90 minutes at ° C, and it is obtained by changing an amorphous layer into a crystalline layer. The means for this conversion is not particularly limited, but an air circulation oven, an IR heater or the like may be used. When patterning a transparent conductive film by the etching process which is mentioned later, crystallization of a transparent conductive film can also be performed before an etching process, and can also be performed after an etching process.

  For the definition of “crystalline”, the transparent conductive film with a transparent conductive film formed on a transparent substrate is immersed in hydrochloric acid with a concentration of 5% by weight at 20 ° C. for 15 minutes, then washed with water and dried. When the inter-terminal resistance is measured with a tester and the inter-terminal resistance does not exceed 10 kΩ, it is assumed that the conversion of the ITO film to crystalline is completed.

  The thickness of the transparent conductive film is preferably 15 nm to 35 nm, and more preferably 20 nm to 30 nm. Within this range, the electrical resistance of the film surface does not increase, it is easy to perform a continuous coating, and a decrease in transparency can be prevented.

  The patterning of the transparent conductive film is preferably performed by etching. In the etching, a method of covering the surface of the region corresponding to the transparent electrode with a mask for forming a pattern and etching the transparent conductive film with an etchant is preferably used. The etchant used for etching the transparent conductive film can be appropriately selected depending on the material forming the transparent conductive film. When ITO or the like is used as the transparent conductive film, an acid is suitably used as an etchant. Examples of the acid include inorganic acids such as hydrogen chloride, hydrogen bromide, sulfuric acid, nitric acid and phosphoric acid, organic acids such as acetic acid, and mixtures thereof, and aqueous solutions thereof. The transparent conductive film can be etched after the amorphous film is formed and before crystallization, or after the crystallization.

  In the transparent conductive film, the thermal contraction rate in the MD direction when heated at 140 ° C. for 90 minutes is preferably 0.45% or less, preferably 0.40% or less, from the viewpoint of suppressing waviness. More preferably, it is still more preferably 0.35% or less. The lower limit value of the thermal contraction rate in the MD direction is not particularly limited, but is preferably 0% or more. The thermal shrinkage in the TD direction is preferably 0.40% or less, more preferably 0.20% or less, and still more preferably 0.10% or less. The lower limit value of the thermal shrinkage rate in the TD direction is not particularly limited, but is preferably -0.10% or more. Further, from the viewpoint of suppressing the occurrence of waviness and improving the pattern visibility, it is preferable that the heat shrinkage rate in the MD direction and the heat shrinkage rate in the TD direction are both 0.4% or less, 0.2% It is more preferable that

  The haze of the cured resin layer of the transparent conductive film of the present invention is preferably less than 0.3%, more preferably 0.2% or less, and still more preferably 0.1% or less. When the haze of the transparent conductive film is high, when used in a touch panel or the like, the clarity of the image is reduced due to light scattering, which tends to cause character blurring of the display screen and the like.

(Protective film)
From the viewpoint of preventing breakage of the transparent conductive film, a protective film can be laminated on the transparent conductive film via a pressure-sensitive adhesive layer described later to obtain a transparent conductive laminate. The protective film contains a polyester resin. By providing the above-mentioned cured resin layer on both sides of the substrate film, the substrate film itself is less likely to be scratched, but it becomes harder and easier to tear. In addition, when the transparent resin film is long, for example, in the process of forming the transparent conductive film, the process of patterning the transparent conductive film, and the like, there is a problem that breakage easily occurs in the transparent resin film during film traveling. From the viewpoint of improving the mechanical strength, the polyester resin film constituting the protective film is preferably subjected to a stretching process such as a uniaxial stretching process or a biaxial stretching process. From the viewpoint of improving mechanical strength and heat resistance, in particular, biaxial stretching is preferably performed. Examples of polyester resins include polyethylene terephthalate resins and polyethylene naphthalate resins. Polyethylene terephthalate resins are preferable in terms of mechanical characteristics, optical characteristics, and availability.

  Although the thickness of a protective film should just be 120 micrometers-250 micrometers, 140 micrometers-220 micrometers are more preferable, and 145 micrometers-190 micrometers are still more preferable. If it is this range, generation | occurrence | production of a curl can be prevented and the working efficiency at the time of winding a film in roll shape etc. can be improved.

(Pressure-sensitive adhesive layer)
The material for forming the pressure-sensitive adhesive layer is not particularly limited as long as it has transparency, but is preferably an acrylic pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, or a silicone-based pressure-sensitive adhesive, more preferably an acrylic pressure-sensitive adhesive It is. The dry thickness of the pressure-sensitive adhesive layer to be formed can be appropriately adjusted, but is usually about 1 to 40 μm, preferably 3 to 35 μm, and more preferably 5 to 30 μm.

<Touch panel>
The touch panel of the present invention uses the transparent resin film and the transparent conductive film described above. For example, the transparent resin film and the transparent conductive film can be suitably applied to a touch panel such as a capacitance method or a resistance film method.

  When forming a touch panel, another base such as glass or a polymer film can be bonded to one or both main surfaces of the transparent conductive film via a transparent pressure-sensitive adhesive layer. For example, you may form the laminated body by which the transparent base | substrate was bonded together through the transparent adhesive layer on the surface by which the transparent conductive film of the transparent conductive film is not formed. The transparent substrate may be composed of a single substrate film, or may be a laminate of two or more substrate films (for example, laminated via a transparent adhesive layer).

  When the transparent resin film and the transparent conductive film according to the present invention are used to form a touch panel, the visibility of a display device such as a touch panel can be improved, and the occurrence of waviness can be prevented.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

Example 1
(Formation of cured resin layer)
Small inorganic particles (BYK) per 100 parts by weight of ultraviolet-curable acrylic resin (Osaka Organic Chemical Industry Co., Ltd., Viscoat 300) on one side of a polyethylene terephthalate film (hereinafter referred to as PET film, manufactured by Mitsubishi Resins Co., Ltd.) of 23 μm thickness 250 parts by weight of NANOBYK-3605 (particle size: 20 nm), 21 parts by weight of inorganic large particles (MP-1040 (particle size: 100 nm) manufactured by Nissan Chemical Co., Ltd.) (Inorganic particles in cured resin layer) Particles (particle size 20 nm) / large particles (particle size 100 nm) = 66.0 / 6.0)), 0.5 parts by weight of leveling agent (manufactured by DIC, GRANDIC PC 4100), and photoinitiator (manufactured by BASF, 5) parts by weight of IRGACURE 907, and adjust the particle loading amount to be 72% of the solid content so that the thickness after drying becomes 1.0 μm Coated, the coating film was dried by heating for 1 minute at 80 ° C.. Then, the cured resin layer containing inorganic particles was formed by irradiating an ultraviolet-ray of 240 mJ / cm < ² > of accumulated light quantities with a high pressure mercury lamp. Next, on the side opposite to the side on which the cured resin layer of the PET film is formed, an ultraviolet-curable acrylic resin is applied in the same manner as described above so that the thickness after drying becomes 1.0 μm, The coating film was dried by heating for 1 minute. After that, a cured resin layer containing inorganic particles was formed on both sides of the PET film by irradiating ultraviolet rays with a cumulative light quantity of 240 mJ / cm ^{2 using} a high pressure mercury lamp.

(Formation of transparent conductive film)
Next, DC magnetron sputtering is performed using a target material of a sintered body having indium oxide and tin oxide in an atmosphere of 4 × 10 ⁻³ Torr consisting of 80 vol% Ar gas and 20 vol% O ₂ gas. Thus, a transparent conductive film was formed with a thickness of 24 nm on the cured resin layer of the PET film.

  Thereafter, the PET film on which the amorphous layer of the indium tin oxide is formed is placed in an air circulating oven, and heat treatment is performed at 140 ° C. for 90 minutes to transform the transparent conductive film from amorphous to crystalline. A transparent conductive film converted to was produced.

(Formation of patterned transparent conductive film)
On the transparent conductive film of this transparent conductive film, a commercially available polyimide tape (2 mm width) was attached along the MD direction at a pitch of 2 mm. The transparent conductive film was immersed in a 10% hydrochloric acid aqueous solution at 50 ° C. for 10 minutes to etch an unnecessary transparent conductive film, and then washed with water. After confirming that the transparent conductive film was etched by surface resistance, the polyimide tape was peeled off. Then, the drying process for 30 minutes was performed at 140 degreeC, and the drying process after etching liquid washing was simulated, and the transparent conductive film in which the patterned transparent conductive film was formed was produced.

Example 2
In Example 1, a transparent conductive film was produced in the same manner as in Example 1 except that the ultraviolet curable acrylic resin mixture was applied on both sides so that the thickness after drying was 3.5 μm.

Example 3
In Example 1, a transparent conductive film was produced in the same manner as in Example 1 except that the ultraviolet curable acrylic resin mixture was applied on both sides so that the thickness after drying was 5.0 μm.

Example 4
200 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size: 20 nm)), large inorganic particles (Nissan Chemical Co., Ltd.) with respect to 100 parts by weight of UV curable acrylic resin (Osaka Organic Chemical Co., Ltd., Biscoat 300) , MP-1040 (particle size 100 nm)) 80 parts by weight (content ratio of inorganic particles: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 52/21)), leveling agent (manufactured by DIC And 0.5 parts by weight of GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (manufactured by BASF, IRGACURE 907) to adjust the particle loading to 73% of the solid content, and the thickness after drying A transparent conductive film was produced in the same manner as in Example 1 except that it was applied to both sides so as to be 2.0 μm.

Example 5
Inorganic small particles (manufactured by BYK, NANOBYK-3605 (particle size 20 nm)) 59.5 parts by weight, inorganic large particles (Nissan large particles) Chem., MP-1040 (particle size 100 nm)) 43 parts by weight (Inorganic particle content ratio: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 29/21)), leveling agent ( 0.5 parts by weight of DIC product, GRANDIC PC 4100, and 5 parts by weight of a photoinitiator (BASF product, IRGACURE 907) were mixed to adjust the particle loading to 50% of the solid content, and after drying A transparent conductive film was produced in the same manner as in Example 1 except that the coating was applied to both sides so as to have a thickness of 2.0 μm.

Example 6
230 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size 20 nm)), large inorganic particles (Nissan Chemical Co., Ltd.) with respect to 100 parts by weight of an ultraviolet curable acrylic resin (Osaka Organic Chemical Co., Ltd., Biscoat 300) Product, MP-1040 (particle size 100 nm)) 20 parts by weight (Inorganic particle content ratio: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 65/6)), leveling agent (made by DIC) , GRANDIC PC 4100) 0.5 parts by weight, and 5 parts by weight of a photoinitiator (manufactured by BASF, IRGACURE 907), and adjusting the particle loading amount to 71% with respect to the solid content, a transparent conductive film of PET film The transparent conductive film was produced by the method similar to Example 1 except having coated so that the thickness after drying might be set to 1.5 micrometers only to the formation side.

Example 7
In Example 6, 250 parts by weight of inorganic small particles (manufactured by BYK, NANOBYK-3605 (particle size: 20 nm)), 100 parts by weight of an ultraviolet-curable acrylic resin (manufactured by Osaka Organic Chemical Industry Ltd., Biscoat 300), Inorganic large Particles (Nissan Chemical Co., MP-1040 (particle size 100 nm)) 21 parts by weight (inorganic particle content ratio: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 66/6)), leveling Except that 0.5 parts by weight of an agent (DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (BASF, IRGACURE 907) were blended to adjust the particle loading to 72% of the solid content, A transparent conductive film was produced in the same manner as in Example 6.

Example 8
In Example 6, 190 parts by weight of inorganic small particles (manufactured by BYK, NANOBYK-3605 (particle size 20 nm)) with respect to 100 parts by weight of ultraviolet curable acrylic resin (manufactured by Osaka Organic Chemical Industry Ltd., Biscoat 300), Inorganic large Particles (Nissan Chemical Co., Ltd., MP-1040 (particle diameter 100 nm)) 77 parts by weight (Inorganic particle content ratio: small particles (particle diameter 20 nm) / large particles (particle diameter 100 nm) = 51/21), Except that 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (made by BASF, IRGACURE 907) were blended and the particle loading amount was adjusted to 72% with respect to the solid content A transparent conductive film was produced in the same manner as in Example 6.

Example 9
In Example 6, 200 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size 20 nm)), 200 parts by weight, and 100 parts by weight of ultraviolet curable acrylic resin (Biscoat 300, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 80 parts by weight of particles (manufactured by Nissan Chemical Industries, MP-1040 (particle size 100 nm)) (content ratio of inorganic particles: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 52/21)), level Except that 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (made by BASF, IRGACURE 907) were blended, and the particle loading amount was adjusted to 73% with respect to solid content A transparent conductive film was produced in the same manner as in Example 6.

Example 10
In Example 6, 277 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size: 20 nm)) are 277 parts by weight with respect to 100 parts by weight of an ultraviolet curable acrylic resin (Biscoat 300, manufactured by Osaka Organic Chemical Industry Co., Ltd.). Particles (manufactured by Nissan Chemical Industries, MP-1040 (particle size 100 nm)) 25 parts by weight (content ratio of inorganic particles: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 68/6)), level Except that 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (made by BASF, IRGACURE 907) were blended and the particle loading amount was adjusted to 74% with respect to the solid content A transparent conductive film was produced in the same manner as in Example 6.

Example 11
In Example 6, 215 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size 20 nm)), 215 parts by weight with respect to 100 parts by weight of an ultraviolet curable acrylic resin (Biscoat 300, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 85 parts by weight of particles (manufactured by Nissan Chemical Industries, MP-1040 (particle size 100 nm)) (content of inorganic particles: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 53/21)), level Except that 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (made by BASF, IRGACURE 907) were blended and the particle loading amount was adjusted to 74% with respect to the solid content A transparent conductive film was produced in the same manner as in Example 6.

Comparative Example 1
In Example 1, 65 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size: 20 nm)) 65 parts by weight, 100 parts by weight of ultraviolet curable acrylic resin (Biscoat 300, manufactured by Osaka Organic Chemical Industry Co., Ltd.) Particles (Nissan Chemical Co., Ltd., MP-1040 (particle diameter 100 nm)) 5 parts by weight (Inorganic particle content ratio: small particles (particle diameter 20 nm) / large particles (particle diameter 100 nm) = 37/3)), 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photo-initiator (made by BASF, IRGACURE 907) were mixed to adjust the particle loading to 40% of the solid content, A transparent conductive film was produced in the same manner as in Example 1 except that the both surfaces were coated such that the thickness after drying was 2.0 μm.

Comparative Example 2
In Comparative Example 1, 280 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle diameter: 20 nm)) are 280 parts by weight with respect to 100 parts by weight of an ultraviolet curable acrylic resin (Biscoat 300, manufactured by Osaka Organic Chemical Industry Co., Ltd.) Particles (manufactured by Nissan Chemical Industries, MP-1040 (particle size 100 nm)) 5 parts by weight (inorganic particle content ratio: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 72/1)), level Except that 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (made by BASF, IRGACURE 907) were blended, and the particle loading amount was adjusted to 73% with respect to solid content A transparent conductive film was produced in the same manner as in Comparative Example 1.

Comparative Example 3
In Comparative Example 1, 10 parts by weight of inorganic small particles (manufactured by BYK, NANOBYK-3605 (particle size: 20 nm)) with respect to 100 parts by weight of ultraviolet curable acrylic resin (manufactured by Osaka Organic Chemical Industry Ltd., Biscoat 300), inorganic large Particles (MP-1040 (particle size 100 nm) manufactured by Nissan Chemical Co., Ltd.) 93 parts by weight (content ratio of inorganic particles: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 5/45)), leveling Except that 0.5 parts by weight of an agent (DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (BASF, IRGACURE 907) were mixed to adjust the particle loading to 50% of the solid content, A transparent conductive film was produced in the same manner as in Comparative Example 1.

Comparative Example 4
In Comparative Example 1, 120 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size 20 nm)) 120 parts by weight, 100 parts by weight of UV curable acrylic resin (Biscoat 300, manufactured by Osaka Organic Chemical Industry Co., Ltd.) Particles (Nissan Chemical Industries, Ltd., MP-1040 (particle size 100 nm)) 150 parts by weight (Inorganic particle content ratio: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 32/40), 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (made by BASF, IRGACURE 907) were mixed to adjust the particle loading to 72% of the solid content, The transparent conductive property was the same as in Comparative Example 1, except that the dry thickness was 1.5 μm only on the side of the PET film on which the transparent conductive film was formed. To prepare a Irumu.

Comparative Example 5
In Comparative Example 1, 235 parts by weight of inorganic small particles (BYK, NANOBYK-3605 (particle size: 20 nm)) 235 parts by weight, 100 parts by weight of UV curable acrylic resin (Osaka Organic Chemical Co., Ltd., Biscoat 300), inorganic large 90 parts by weight of particles (manufactured by Nissan Chemical Industries, MP-1040 (particle size 100 nm)) (content ratio of inorganic particles: small particles (particle size 20 nm) / large particles (particle size 100 nm) = 55/21)), level 0.5 parts by weight of a ring agent (made by DIC, GRANDIC PC 4100) and 5 parts by weight of a photoinitiator (made by BASF, IRGACURE 907) were blended to adjust the particle loading to 76% of the solid content, and A transparent conductive film was prepared by the same method as Comparative Example 1 except that the dry thickness was 1.5 μm only on the transparent conductive film formation side of the PET film. It was produced Lum.

<Evaluation>
(1) Measurement of thickness The thickness of less than 1.0 μm was measured by observing the cross section of the transparent conductive film using a transmission electron microscope (product name “H-7650” manufactured by Hitachi, Ltd.). The thickness of 1.0 μm or more was measured by using a film thickness meter (manufactured by Peacock, digital dial gauge DG-205). The evaluated results are shown in Table 1.

(2) Thermal contraction rates in MD and TD directions The thermal contraction rates in the longitudinal direction (MD direction) and the width direction (TD direction) of the transparent resin film and the transparent conductive film were calculated as follows. Specifically, the film is cut into a width of 100 mm and a length of 100 mm (test piece), and a straight line of 80 mm in length is drawn in each of the MD direction and the TD direction, and a cross is marked to make the MD direction and the TD direction. The length of the mark (mm) was measured with an Olympus digital small measurement microscope STM5 (manufactured by Olympus Optical Co., Ltd.). Thereafter, heat treatment (140 ° C., 90 minutes) was performed. After being allowed to cool for 1 hour at room temperature, the lengths of the marks in the MD direction and the TD direction were measured again, and the measured values were substituted into the following equation to determine the heat shrinkage rates in the MD direction and the TD direction. The evaluated results are shown in Table 1.
Thermal shrinkage (%) = [[length of mark before heating (mm) −length of mark after heating (mm)] / length of mark before heating (mm) × 100

(3) Measurement of waviness The laminate of the transparent conductive film is dried at 140 ° C. for 30 minutes, and the waviness of the portion with and without the transparent electrode pattern of the transparent conductive film obtained after the etching step (high and low Difference) was evaluated visually. The evaluated results are shown in Table 1.

<Evaluation criteria>
◎: Swelling is prevented and very good
○: Swelling is prevented and good
×: Swelling occurs

(4) Measurement of Haze The haze of the surface (cured resin layer side) of the transparent resin film was measured using Direct reading haze computer (product name "HGM-ZDP" manufactured by Suga Test Instruments). In order to measure the external haze of the cured resin layer alone, it was measured according to the following procedure. That is, the haze of the surface of the transparent resin film with a cured resin layer was measured (i). A glass (a slide glass made of MATSUNAMI having a thickness of 1.2 to 1.5 mm) was attached to the surface of the cured resin layer on the surface of the cured resin layer-containing transparent resin film measured in i via an adhesive to measure the haze (ii). The haze of only the cured resin layer was calculated by the difference (i-ii) between i and ii. The evaluation results are shown in Table 1.

(5) Measurement of surface resistance value According to JIS K 7194, it measured by the four probe method.

(Results and discussion)
In Examples 1 to 11, no waviness occurred, the haze was small, and good results were obtained. On the other hand, in Comparative Examples 1 and 2, the addition amount of the large particles in the cured resin layer was too small, so the haze was improved although the haze was improved. Moreover, in Comparative Examples 3 to 5, although the amount of large particles added in the cured resin layer was too large, although the generation of waviness could be suppressed, the haze was large.

Reference Signs List 1 base film 2 cured resin layer 3 resin 4 inorganic particle 41 small particle 42 large particle 5 transparent conductive film

Claims (7)

A transparent resin film having a cured resin layer on at least one surface side of a base film,
The thickness of the cured resin layer is 0.5 μm to 10 μm,
The cured resin layer includes a resin and inorganic particles,
The inorganic particles include small particles having a particle size of 10 nm to 60 nm and large particles having a particle size of more than 60 nm and 500 nm or less,
The small particles are contained in an amount of 25 to 74% by weight in the cured resin layer,
The large particles are contained in the cured resin layer in an amount of 1 to 30% by weight,
The total of the large particles and the small particles is contained in the cured resin layer in an amount of 46 to 75% by weight ,
The transparent resin film whose ratio which divided content of the said large particle by content of the said small particle is 0.05-0.75 .   The transparent resin film according to claim 1, wherein the heat shrinkage rate in the MD direction when the transparent resin film is heated at 140 ° C. for 90 minutes is 0.45% or less. The transparent resin film of Claim 1 or 2 whose haze of the cured resin layer of the said transparent resin film is less than 0.3%. The transparent resin film according to any one of claims 1 to 3 , wherein the heat shrinkage ratio in the MD direction and the TD direction is 0.4% or less when the transparent resin film is heated at 140 ° C for 90 minutes. . The transparent conductive film in which the transparent conductive film is formed in the at least one surface side of the transparent resin film of any one of Claims 1-4 . The transparent conductive film according to claim 5 , further comprising one or more optical adjustment layers between the transparent resin film and the transparent conductive film. A touch panel comprising the transparent conductive film according to claim 5 or 6 .

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