KR102432417B1 - Transparent conductive film and touch panel - Google Patents

Abstract

A transparent conductive film having excellent heat-and-moisture resistance and a touch panel provided with the transparent conductive film are provided. A transparent conductive film having a cured resin layer and a transparent conductive film on a transparent resin film in this order, wherein the cured resin layer has a thickness of 100 nm or less, the transparent conductive film is patterned, a temperature of 85° C., a humidity of 85 The transparent conductive film whose rate of change of the surface resistance value of the said transparent conductive film before and behind setting it in % atmosphere for 240 hours is 1.5 or less.

Description

Transparent conductive film and touch panel

The present invention relates to a transparent conductive film and a touch panel.

In recent years, in the touch panel display device which is spreading rapidly, the transparent electrode which consists of transparent conductive layers, such as an indium-tin composite oxide (ITO), is used. The conductor with the transparent electrode used in the touch panel basically uses glass or a plastic film as a substrate. In particular, in a smart phone or tablet that requires portability, from the viewpoint of thinness and weight, transparent conductivity using a plastic film Film is widely used.

A transparent conductive film having, for example, a transparent conductive film patterned on one surface of the transparent resin film through at least one cured resin layer for the above-mentioned touch panel use is proposed (Patent Document 1).

Japanese Patent Laid-Open No. 2009-76432

For touch panel applications mounted on smartphones or car navigation systems that may be placed under high temperature and high humidity, for example, it has a high heat-and-moisture durability that does not interfere with operation even under more severe conditions than conventional conditions such as 85 ° C and 85 % RH. strongly demanded. However, when the moisture-and-heat resistance test in 85 degreeC 85%RH atmosphere was implemented about the transparent conductive film which concerns on the said technique, cracks generate|occur|produced in the patterned transparent conductive film, and it became clear newly that an electrical characteristic fell.

An object of this invention is to provide the transparent conductive film which has the outstanding heat-and-moisture resistance, and the touch panel provided with the said transparent conductive film.

As a result of the inventors of the present application, as a result of intensive studies to solve the above problems, when a transparent conductive film with a patterned transparent conductive film is placed under a high temperature and high humidity environment, the transparent resin film expands due to moisture absorption, and the transparent conductive film expands due to this expansion. It became impossible to follow, and the knowledge that a crack in the transparent conductive film may have occurred was acquired. As a result of further examination, the present inventors discovered that the said objective could be achieved by employ|adopting the following structure, and came to complete this invention.

That is, the present invention provides a transparent conductive film having a cured resin layer and a transparent conductive film in this order on a transparent resin film,

The cured resin layer is a cured product film obtained by curing a resin composition containing an epoxy resin having a weight average molecular weight of 1500 or more,

The thickness of the cured resin layer is 150 nm or less,

It is related with the transparent conductive film whose surface elasticity modulus of the said cured resin layer is 4 GPa or more and 12 GPa or less.

In the transparent conductive film, a cured resin layer is formed using a resin composition containing an epoxy resin having a weight average molecular weight of 1500 or more, and the surface elastic modulus of the cured resin layer is 4 GPa or more and 12 GPa or less, so that crystallinity is A cured product film having a high, three-dimensional crosslinked structure can be formed, and the film strength of the cured resin layer is increased. Thereby, the improvement of the water resistance and expansion resistance of a cured resin layer becomes possible, As a result, the heat-and-moisture resistance of the transparent conductive film when a transparent conductive film is patterned can be improved. When the weight average molecular weight of the epoxy resin is less than 1500 or the surface elastic modulus of the cured resin layer is less than 4 GPa, the film strength of the cured resin layer becomes insufficient, and there is a possibility that the heat-and-moisture resistance of the transparent conductive film may decrease. Moreover, when the surface elasticity modulus of a cured resin layer exceeds 12 GPa, the softness|flexibility of a cured resin layer falls, and when a transparent conductive film is bent, there exists a possibility that whitening and a crack may generate|occur|produce.

It is preferable that the gelation time when the mixture of the said resin composition and the said hardening accelerator of the said epoxy resin is heated at 170 degreeC is 50 second or less. The gelation time is generally an indicator of the reactivity of the target composition or the like, particularly the curing reactivity, and the shorter the gelation time, the higher the curing reactivity. By setting the gelation time of the resin composition to which the curing accelerator is added to 50 seconds or less, the curing reaction of the resin composition can be rapidly and sufficiently advanced, and a stronger cured product film can be formed.

It is preferred that the curing accelerator contains antimony. Since the curing accelerator containing antimony has high reactivity, the curing reaction of the resin composition can be rapidly and sufficiently advanced, and a stronger cured product film can be efficiently formed.

It is preferable that the said epoxy resin is a rubber-modified epoxy resin. Thereby, toughness and impact resistance can be provided suitably to a cured resin layer.

It is preferable that the saturation expansion coefficient in the atmosphere of the temperature of 85 degreeC of the said cured resin layer and 85% of humidity is 0.5 % or less. By making the saturation expansion coefficient of a cured resin layer into such a range, heat-and-moisture resistance of a transparent conductive film is improved, and the stability and reliability of the output of an electrical characteristic can be improved.

It is preferable that the said transparent conductive film is patterned, and the rate of change of the surface resistance value before and after putting the said transparent conductive film in the atmosphere of 85 degreeC of temperature and 85% of humidity for 240 hours is 1.5 or less. By setting the rate of change of the surface resistance value before and after exposure to a high-temperature, high-humidity atmosphere within the above range, desired electrical properties can be exhibited even when placed in a harsh environment, thereby enabling various applications to be developed.

The present invention also relates to a touch panel including the transparent conductive film. Since the said touchscreen uses the transparent conductive film with high heat-and-moisture resistance, the outstanding durability and weather resistance can be exhibited.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the transparent conductive film which concerns on one Embodiment of this invention.
2 is a cross-sectional view showing a transparent conductive film according to an embodiment of the present invention.
It is sectional drawing which shows the transparent conductive film which concerns on one Embodiment of this invention.
It is sectional drawing which shows the transparent conductive film which concerns on one Embodiment of this invention.
5 is a top view showing an example of a pattern of the transparent conductive film of the present invention.

EMBODIMENT OF THE INVENTION Embodiment of this invention is described below, referring drawings. In addition, parts unnecessary for the description are omitted, and some parts are enlarged or reduced in order to facilitate the explanation.

<First embodiment>

(Transparent conductive film)

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of the transparent conductive film of this embodiment. The transparent conductive film of FIG. 1 has the transparent conductive film 3 on the single side|surface of the transparent resin film 1 through the cured resin layer 2 interposing. The transparent conductive film 3 is patterned. In addition, in each figure, the thing in which the transparent conductive film 3 is patterned is the pattern part (a) which has the transparent conductive film 3, and the non-pattern part (b) which does not have the transparent conductive film 3 is shown to have Moreover, it has the said cured resin layer 2 in the said non-patterned part (b).

(Transparent resin film)

Although it does not restrict|limit especially as said transparent resin film 1, Various plastic films which have transparency are used. For example, as the material, polyester-based resin, acetate-based resin, polyethersulfone-based resin, polycarbonate-based resin, polyamide-based resin, polyimide-based resin, polyolefin-based resin, polycycloolefin-based resin, (meth ) acrylic resins, polyvinyl chloride-based resins, polyvinylidene chloride-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, polyarylate-based resins, and polyphenylene sulfide-based resins. Among these, polyester-based resins, polycarbonate-based resins, and polyolefin-based resins are particularly preferable.

The thickness of the transparent resin film 1 is not particularly limited, but may be in the range of 5 µm or more and 200 µm or less, 20 µm or more and 130 µm or less, and may be in the range of 40 µm or more and 130 µm or less. . In general, the thicker the transparent resin film (1), the higher the hygroscopicity and the easier to expand. can perform

The transparent resin film 1 is subjected to etching treatment or undercoating such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, etc. on the surface in advance, and the cured resin layer 2 formed thereon. You may make it improve the adhesiveness with respect to the said transparent resin film (1). Moreover, before forming the cured resin layer 2, you may dust removal and cleaning by solvent washing|cleaning, ultrasonic washing|cleaning, etc. as needed.

(Cured resin layer)

The cured resin layer 2 is a cured product film obtained by curing a resin composition containing an epoxy resin having a weight average molecular weight of 1500 or more (hereinafter, also referred to as a "high molecular weight epoxy resin" for convenience). It is preferable that a high molecular weight epoxy resin is a main component of a resin composition. A main component means that it is the component with the largest content among the components contained in a resin composition, 20 weight% or more is preferable with respect to the total amount of the resin composition, and, as for the content, 40 weight% or more is more preferable.

As the high molecular weight epoxy resin, widely used ones can be used, and an epoxy group-containing compound having one or more, preferably two or more, epoxy groups such as glycidyl group, alicyclic epoxy group, and aliphatic epoxy group in the molecule is used. can Specifically, for example, an epichlorohydrin-bisphenol A type epoxy resin, an epichlorohydrin-bisphenol F type epoxy resin, a flame retardant epoxy resin such as glycidyl ether of tetrabromobisphenol A, a novolac type Epoxy resin, phenol novolak type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, glycidyl ether type epoxy resin of bisphenol A propylene oxide adduct, p-oxybenzoic acid-glycidyl ether ester Type epoxy resin, III-aminophenol type epoxy resin, diaminodiphenylmethane type epoxy resin, various alicyclic epoxy resins, N,N-diglycidylaniline, N,N-diglycidyl-o-toluidine, Epoxides of unsaturated polymers such as triglycidyl isocyanurate, polyalkylene glycol diglycidyl ether, glycidyl ether of polyhydric alcohols such as glycerin, hydantoin type epoxy resin, polysiloxane having an epoxy group, petroleum resin, etc. Among the epoxy resins of , an epoxy resin having a weight average molecular weight of 1500 or more is exemplified. A high molecular weight epoxy resin may be used independently and may use 2 or more types together.

Among them, as the high molecular weight epoxy resin, a hydrogenated bisphenol A type epoxy resin or a hydrogenated bisphenol F type epoxy resin having a weight average molecular weight of 1500 or more is preferable from the viewpoint of strength, flexibility, and weather resistance of the resulting cured product film.

Together with the high molecular weight epoxy resin, an epoxy resin having a weight average molecular weight of less than 1500 among the epoxy resins enumerated above (hereinafter also referred to as a "low molecular weight epoxy resin" for convenience) can be used. As a low molecular weight epoxy resin, an alicyclic epoxy resin is preferable. As an alicyclic epoxy resin, a well-known thing can be employ|adopted preferably, For example, 3,4-epoxycyclohexylmethyl-3,4- epoxycyclohexane carboxylate, ε-caprolactone-modified 3',4 '-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexane-1-carboxylate allyl, having a weight average molecular weight of less than 1500 Hydrogenated bisphenol A epoxy resin etc. are mentioned. A low molecular weight epoxy resin may be used independently and may use 2 or more types together.

The weight average molecular weight of a high molecular weight epoxy resin should just be 1500 or more, 1700 or more are preferable and 1800 or more are more preferable. Moreover, from a viewpoint of the embrittlement suppression by excessive hardening of the cured resin layer obtained, 5000 is preferable and, as for the upper limit of the said weight average molecular weight, 2000 is more preferable. By making the weight average molecular weight of the epoxy resin into the above range, a cured resin layer having high crystallinity and excellent film strength can be formed.

In addition, in this specification, a weight average molecular weight is the value computed by polystyrene conversion by measuring by GPC (Gel permeation chromatography, HLC-8320GPC by TOSOH). The measurement conditions are as follows. Column: SHODEXGPC KF-802.5/GPC KF-G, Column size: 6.0 mm inner diameter x 150 mm, solvent: tetrahydrofuran (THF), solution concentration: 0.05 wt%, flow rate: 1 ml/min, detector: differential refractometer ( RI), column temperature: 40 °C, injection amount: 2 ml

It is preferable that a high molecular weight epoxy resin is a rubber-modified epoxy resin. Thereby, toughness and impact resistance can be provided suitably to a cured resin layer. The rubber component for modifying the epoxy resin is not particularly limited, butadiene rubber, acrylonitrile butadiene rubber, styrene-butadiene rubber, butyl rubber, nitrile rubber, natural rubber, isoprene rubber, chloroprene rubber, ethylene-propylene rubber, urethane rubber , silicone rubber, fluororubber, ethylene-vinyl acetate rubber, epichlorohydrin rubber, and the like. Among them, butadiene rubber is preferable from the viewpoint of toughness and chemical resistance. A rubber-modified epoxy resin may be used independently and may use 2 or more types together.

A method for preparing a rubber-modified epoxy resin may employ a conventionally known method. For example, a carboxyl group is introduced at the end of a polymer main chain of a rubber component, and the carboxyl group and the epoxy group of the epoxy resin are phosphorus-based catalysts or amine-based catalysts. The method of making it react in catalyst presence, such as these, etc. are mentioned.

It is preferable that the said resin composition contains a hardening accelerator. Thereby, the hardening reaction of an epoxy resin can advance rapidly and fully, and the hardened|cured material film|membrane with high film strength can be formed. It does not specifically limit as a hardening accelerator, For example, Organometallic salts, such as zinc, copper, iron, antimony, of organic acids, such as octanoic acid, stearic acid, acetylacetonate, naphthenic acid, and salicylic acid; A metal chelate etc. are mentioned. Especially, it is preferable that the hardening accelerator contains antimony. An antimony containing hardening accelerator can advance the hardening reaction of a resin composition rapidly and fully, and can form a stronger hardened|cured material film efficiently. In addition, a hardening accelerator can be used individually or in combination of 2 or more type.

Although content of a hardening accelerator is not specifically limited, 0.005-5 weight part is preferable with respect to the total amount (100 weight part) of the compound which has an epoxy group contained in a resin composition, More preferably, 0.01-4 weight part, further Preferably it is 0.01-1 weight part. When content of a hardening accelerator is less than the said minimum, the hardening acceleration effect may become inadequate. On the other hand, when content of a hardening accelerator exceeds the said upper limit, hardened|cured material may be colored and a hue may deteriorate.

When the mixture of the said resin composition and the said hardening accelerator of the said epoxy resin is heated at 170 degreeC, it is preferable that it is 50 second or less, and, as for the gelation time, it is more preferable that it is 20 second or less. By setting the gelation time of the resin composition to which the curing accelerator is added to 50 seconds or less, the curing reaction of the resin composition can be rapidly and sufficiently advanced, and a stronger cured product film can be formed. In addition, although it is preferable that the said gelation time is shorter, it is preferable that it is 10 second or more from a viewpoint of the stability of a mixture and handling property.

You may mix|blend suitably an acrylic resin, a urethane resin, an amide resin, a silicone resin, etc. with a resin composition other than an epoxy resin. In addition, various additives may be added to the resin composition. As an additive, a leveling agent, a pigment, a filler, a dispersing agent, a plasticizer, a ultraviolet absorber, surfactant, antioxidant, a thixotropy agent, etc. can be used, for example.

(Physical properties of cured resin layer)

The surface elastic modulus of a cured resin layer should just be 4 GPa or more and 12 GPa or less. Moreover, 4.5 GPa or more is preferable and, as for the said surface elasticity modulus, 5 GPa or more is more preferable. Moreover, 10 GPa or less is preferable and, as for the said surface elasticity modulus, 9 GPa or less is more preferable. When the surface elastic modulus of the cured resin layer is less than the above lower limit, the film strength of the cured resin layer becomes insufficient, and there is a possibility that the heat-and-moisture resistance of the transparent conductive film may decrease. On the other hand, when the surface elastic modulus of a cured resin layer exceeds the said upper limit, the softness|flexibility of a cured resin layer falls, and when a transparent conductive film is bent, there exists a possibility that whitening and a crack may generate|occur|produce.

It is preferable that the saturation expansion coefficient in the temperature of 85 degreeC of temperature of a cured resin layer, and the atmosphere of 85% of humidity is 0.5 % or less, and its 0.4 % or less is more preferable. By making the saturation expansion coefficient of a cured resin layer into such a range, heat-and-moisture resistance of a transparent conductive film is improved, and the stability and reliability of the output of an electrical characteristic can be improved. Moreover, although the said saturation expansion coefficient is so preferable that it is low, it is preferable from the point of the softness|flexibility of a cured resin layer that it is 0.05 % or more. A saturation expansion coefficient is calculated|required by injecting|throwing-in a film in the atmosphere of 85 degreeC temperature and 85% of humidity using a thermomechanical measuring apparatus (TMA), and calculating|requiring the dimensional change amount when it becomes a saturated state.

The cured resin layer 2 is formed between the transparent resin film 1 and the transparent conductive film 3, and does not have a function as a conductor layer. That is, the cured resin layer 2 is formed as a dielectric layer so that it can insulate between the patterned transparent conductive films 3 . Therefore, the cured resin layer 2 usually has a surface resistance of 1×10 ⁶ Ω/□ or more, preferably 1×10 ⁷ Ω/□ or more, and more preferably 1×10 ⁸ Ω/□ or more. . In addition, there is no upper limit in particular of the surface resistance of the cured resin layer 2. In general, the upper limit of the surface resistance of the cured resin layer 2 is about 1×10 ¹³ Ω/□, which is the measurement limit, but may exceed 1×10 ¹³ Ω/□.

The thickness of the cured resin layer 2 is not particularly limited, but is 150 nm or less, preferably 20 to 100, in terms of heat-and-moisture resistance, the effect of preventing oligomer generation from the transparent resin film 1, and optical properties. It is about nm, More preferably, it is 30-50 nm. Moreover, when forming the cured resin layer 2 in two or more layers, the thickness of each layer is about 20-60 nm, Preferably it is 25-55 nm.

In this embodiment, by having the patterned transparent conductive film 3 and the cured resin layer 2, the thing favorable in an external appearance as a display element is obtained. From such a viewpoint, it is preferable that the refractive index of the cured resin layer 2 has a difference of 0.1 or more between the refractive index of the transparent conductive film 3 and the refractive index of the cured resin layer. The difference between the refractive index of the transparent conductive film 3 and the refractive index of the cured resin layer is preferably 0.1 or more and 0.9 or less, and further preferably 0.1 or more and 0.6 or less. Moreover, it is preferable that the refractive index of the cured resin layer 2 is 1.3-2.5 normally, Furthermore, it is 1.38-2.3, Furthermore, it is preferable that it is 1.4-2.3.

As for the transparent conductive film 3, as mentioned above, it is preferable that the difference of the refractive index with the cured resin layer 2 is 0.1 or more. The refractive index of the transparent conductive film 3 is about 1.95-2.05 normally.

Although the formation method of a cured resin layer is not specifically limited, The thing by coating is preferable. First, the resin composition which mix|blended the above-mentioned component is melt|dissolved and disperse|distributed uniformly in a solvent, and a coating solution is prepared. It does not specifically limit as a solvent, For example, Aromatic solvents, such as toluene and xylene; Ketone solvents, such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; Diethyl ether, isopropyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, anisole, phenetol ether solvents such as; ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, and ethylene glycol diacetate; amide solvents such as dimethylformamide, diethylformamide, and N-methylpyrrolidone; cellosolve solvents such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; Alcohol solvents, such as methanol, ethanol, and a propanol; and halogen-based solvents such as dichloromethane and chloroform. These solvents may be used independently and may be used in combination of 2 or more type.

0.5 weight% - 2.5 weight% are preferable, as for the solid content concentration of a coating solution, 1.0 weight% - 2.0 weight% are more preferable, 1.5 weight% - 1.9 weight% are especially preferable.

A cured resin layer is formed by apply|coating the said coating solution on a transparent resin film, and hardening it. In addition, application|coating of a coating solution may be performed directly on the transparent resin film 1, and may be performed on the undercoat layer etc. which were formed on the transparent resin film 1.

The coating method of the coating solution can be appropriately selected depending on the conditions of the coating solution and the coating process, for example, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, It can apply by the die-coating method, the extrusion-coating method, etc.

Finally, a cured resin layer can be formed by heat-hardening the obtained coating film. As a heating method, heating by a hot air dryer, an infrared dryer, a vacuum dryer, a microwave heating dryer, etc. is employable. As heating temperature, it is 100-200 degreeC, for example, and 120-180 degreeC is preferable. As a heating time, it is for 0.5 to 10 minutes, for example, and 1 to 5 minutes is preferable.

(transparent conductive film)

The material constituting the transparent conductive film 3 is not particularly limited, and is selected from the group consisting of indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten. A metal oxide of at least one selected metal is used. The said metal oxide may contain the metal atom shown in the said group further as needed. For example, indium oxide containing tin oxide, tin oxide containing antimony, etc. are preferably used.

Although the thickness in particular of the transparent conductive film 3 is not restrict|limited, In order to make the surface resistance into a continuous film which has favorable electroconductivity of 1x10 ³ ohm/square or less, it is preferable to set it as thickness 10 nm or more. Since a fall of transparency etc. will be caused when a film thickness becomes too thick, it is preferable that it is 15-35 nm, More preferably, it exists in the range of 20-30 nm. When the thickness is less than 10 nm, the surface electrical resistance becomes high and it becomes difficult to form a continuous film. Moreover, when it exceeds 35 nm, the fall of transparency etc. will be caused.

It does not specifically limit as a formation method of the transparent conductive film 3, A conventionally well-known method is employable. Specifically, a vacuum vapor deposition method, a sputtering method, and an ion plating method can be illustrated, for example. Moreover, an appropriate method can also be employ|adopted according to the required film thickness. Moreover, after forming the transparent conductive film 3, it can anneal and crystallize within the range of 100-150 degreeC as needed. For this reason, it is preferable that the transparent resin film 1 has heat resistance of 100 degreeC or more, Furthermore, 150 degreeC or more. In this embodiment, the transparent conductive film 3 is etched and patterned. Since etching may become difficult when the transparent conductive film 3 is crystallized, it is preferable to carry out the annealing process of the transparent conductive film 3 after patterning the transparent conductive film 3. Furthermore, when etching the cured resin layer 2, it is preferable to perform annealing process of the transparent conductive film 3 after etching of the cured resin layer 2.

The transparent conductive film 3 may be patterned on the cured resin layer 2 . Patterning can form various patterns according to the use to which a transparent conductive film is applied in various aspects. Moreover, a pattern part and a non-pattern part are formed by patterning of the transparent conductive film 3, As a shape of a pattern part, stripe shape etc. are mentioned, for example. 5 is a top view of the transparent conductive film of the present embodiment, and is an example of a case where the transparent conductive film 3 is formed in a stripe shape, and the patterned portion (a) and the non-patterned portion of the transparent conductive film 3 are (b) is formed in a stripe shape. In addition, in FIG. 5, although the width|variety of the pattern part (a) is larger than the width|variety of the non-pattern part (b), it is not limited to this range.

It is preferable that it is 1.5 or less, and, as for the rate of change of the surface resistance value of the transparent conductive film before and behind putting the patterned transparent conductive film in the atmosphere of 85 degreeC of temperature and 85% of humidity for 240 hours, it is more preferable that it is 1.3 or less. Thereby, even when the transparent conductive film is placed in a harsh environment, desired electrical properties can be exhibited, thereby enabling various applications to be developed.

(Other configurations)

A hard-coat layer, an easily bonding layer, a blocking prevention layer, etc. may be formed in the surface on the opposite side to the surface in which the transparent conductive film 3 of the transparent resin film 1 is formed as needed.

(Manufacturing method of transparent conductive film)

As for the manufacturing method of the transparent conductive film of this embodiment, if a cured resin layer and a transparent conductive film have the said structure on one side or both surfaces of a transparent resin film, the manufacturing method in particular is not restrict|limited. For example, as usual, on one or both sides of the transparent resin film, at least one cured resin layer is interposed from the transparent resin film side to prepare a transparent conductive film having a transparent conductive film, and then the transparent conductive film is etched It can be manufactured by patterning. At the time of etching, the transparent conductive film is covered with a mask for forming a pattern, and the transparent conductive film is etched with an etchant.

As for the transparent conductive film, indium oxide containing tin oxide and tin oxide containing antimony are preferably used, and therefore, an acid is preferably used as the 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, mixtures thereof, and aqueous solutions thereof.

Moreover, on one side of the transparent conductive film of this embodiment, the transparent adhesive layer 4 so that the said patterned transparent conductive film 3 is arrange|positioned on the single side|surface of the transparent conductive film to which the transparent base 5 was bonded ), the transparent substrate 5 can be bonded together. 4 is a structure in which a transparent base 5 is bonded to a transparent resin film 1 (surface on which the transparent conductive film 3 is not formed) of the transparent conductive film of FIG. 1 via a transparent pressure-sensitive adhesive layer 4; It is a transparent conductive film. The transparent substrate 5 may have a composite structure in which at least two transparent substrate films are bonded together with a transparent pressure-sensitive adhesive layer. In addition, the patterning of the said transparent conductive film 3 can also be performed with respect to the transparent conductive film made into such a structure.

It is preferable that the thickness of the transparent substrate 5 is 90-300 micrometers normally, More preferably, it is controlled to 100-250 micrometers. Further, when the transparent substrate 5 is formed of a plurality of substrate films, the thickness of each substrate film is 10 to 200 μm, furthermore, 20 to 150 μm, and the transparent substrate 5 including a transparent pressure-sensitive adhesive layer in these substrate films. ) is controlled to fall within the above range. As a base film, the thing similar to the above-mentioned transparent resin film (1) is mentioned.

In bonding the transparent conductive film (eg, transparent resin film 1) and the transparent substrate 5, the pressure-sensitive adhesive layer 4 is formed on the transparent substrate 5 side, and the transparent resin film 1 ) may be bonded, or conversely, the pressure-sensitive adhesive layer 4 may be provided on the transparent resin film 1 side, and the transparent base 5 may be bonded thereto. In the latter method, since formation of the adhesive layer 4 can be performed continuously by making the transparent resin film 1 into roll shape, it is further advantageous from the point of productivity. Moreover, the transparent base 5 can also be laminated|stacked by bonding a some base film sequentially to the transparent resin film 1 with an adhesive layer. In addition, the thing similar to the following transparent adhesive layer 4 can be used for the transparent adhesive layer used for lamination|stacking of a base film. Moreover, also at the time of bonding of transparent conductive films, the lamination|stacking surface of the transparent conductive film which laminates|stacks the adhesive layer 4 suitably can be selected, and transparent conductive films can be bonded together.

As the adhesive layer 4, if it has transparency, it can use without a restriction|limiting in particular. Specifically, for example, acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate/vinyl chloride copolymer, modified polyolefin, epoxy, fluorine, natural rubber, synthetic rubber, etc. Those which use polymers, such as a rubber type, as a base polymer can be used, selecting suitably. In particular, it is excellent in optical transparency, shows adhesive characteristics, such as moderate wettability, cohesiveness, and adhesiveness, and is excellent also in weather resistance, heat resistance, etc. at the point, an acrylic adhesive is used preferably.

Depending on the kind of the adhesive which is a constituent material of the adhesive layer 4, it may be possible to improve anchoring force by using an appropriate undercoating agent for adhesion. Therefore, when using such an adhesive, it is preferable to use the primer for adhesion.

There is no restriction|limiting in particular as said primer for adhesion, if it can improve anchoring force of an adhesive. Specifically, for example, a silane-based coupling agent having a reactive functional group such as an amino group, a vinyl group, an epoxy group, a mercapto group, and a chlor group in the same molecule and a hydrolyzable alkoxysilyl group, a hydrolyzable titanium-containing in the same molecule So-called coupling agents, such as titanate coupling agents having a hydrophilic group and an organic functional group, and an aluminate coupling agent having a hydrolyzable hydrophilic group and organic functional group containing aluminum in the same molecule, epoxy resins, isocyanate resins , a resin having an organic reactive group such as a urethane-based resin or an ester urethane-based resin can be used. From the viewpoint of being easy to handle industrially, a layer containing a silane-based coupling agent is particularly preferable.

Moreover, the said adhesive layer 4 can be made to contain the crosslinking agent according to a base polymer. In addition, in the pressure-sensitive adhesive layer 4, if necessary, suitable additives such as natural or synthetic resins, glass fibers or glass beads, metal powders and other inorganic powders, fillers, pigments, colorants, antioxidants and the like are added. It can also be combined. Moreover, it can also be set as the adhesive layer 4 to which light diffusivity was provided by containing transparent microparticles|fine-particles.

In addition, the transparent fine particles include, for example, conductive inorganic fine particles such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle diameter of 0.5 to 20 μm, and polymethyl One or two or more types of suitable crosslinked or uncrosslinked organic fine particles made of an appropriate polymer such as methacrylate or polyurethane may be used.

The said adhesive layer 4 is normally used as an adhesive solution whose solid content concentration is about 10 to 50 weight% which melt|dissolved or disperse|distributed the base polymer or its composition in the solvent. As said solvent, organic solvents, such as toluene and ethyl acetate, and the thing according to the kind of adhesives, such as water, can be selected suitably and can be used.

Moreover, when the thickness of the pressure-sensitive adhesive layer 4 is less than 1 µm, the cushioning effect cannot be expected, so it is difficult to improve the scratch resistance of the transparent conductive film 3, pen input durability for touch panels, and surface pressure durability. tends to break On the other hand, when it thickens too much, transparency will be inhibited, or the formation of the adhesive layer 4, bonding workability|operativity of the transparent base 5, and a good result will also be hard to be obtained from the point of cost.

The transparent substrate 5 bonded through such an adhesive layer 4 imparts good mechanical strength to the transparent resin film 1, and in addition to pen input durability and surface pressure durability, in particular, contributes to prevention of occurrence of curls or the like will do

When using the release film (S) to transfer the pressure-sensitive adhesive layer (4), as such a release film (S), for example, on the surface to be adhered to at least the pressure-sensitive adhesive layer (4) of the polyester film, a migration prevention layer and / Or it is preferable to use the polyester film etc. in which the release layer was laminated|stacked.

It is preferable that it is 30 micrometers or more, and, as for the total thickness of the said release film (S), it is more preferable to exist in the range of 60-100 micrometers. It is for suppressing the deformation|transformation (striation) of the adhesive layer 4 which is assumed to generate|occur|produce by the foreign material etc. which entered between rolls when storing in roll state after formation of the adhesive layer 4.

(touch panel)

The transparent conductive film of this embodiment can be preferably applied to touch panels, such as an optical system, an ultrasonic system, a capacitive system, and a resistive film system, for example. In particular, it is suitable for a capacitive touch panel. In addition, the transparent conductive film of the present embodiment is, for example, an electrophoretic method, a twist ball method, a thermal rewrite method, an optical recording liquid crystal method, a polymer dispersed liquid crystal method, a guest/host liquid crystal method, and a toner display method. .

<Second embodiment>

In the first embodiment, one cured resin layer is formed, whereas in the present embodiment two layers are formed. 2 : is a case where the cured resin layer 2 has two layers. In FIG. 2 , the cured resin layers 21 and 22 are formed in this order from the side of the transparent resin film 1 . In FIG. 2, it is a case where it has the cured resin layers 21 and 22 in the non-pattern part (b). The cured resin layer 22 above the first layer may or may not be patterned.

In addition to the material for forming the cured resin layer in the first embodiment, an inorganic substance can be preferably used in the present embodiment. For example, as an 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), SiO ₂ (1.46), LaF ₃ (1.55), CeF ₃ (1.63), Al ₂ O ₃ (1.63), and other inorganic substances [the numerical values in parentheses of the above materials are the refractive index of light] are exemplified. Among these, SiO2 _, MgF2 _, Al2O3 _, etc. are used preferably _{. In} particular, SiO2 is preferable. In addition to the above, a complex oxide containing about 10 to 40 parts by weight of cerium oxide and about 0 to 20 parts by weight of tin oxide can be used with respect to indium oxide.

The cured resin layer formed of an inorganic substance can be formed by a dry process such as a vacuum vapor deposition method, a sputtering method, or an ion plating method, or by a wet method (coating method) or the like. As an inorganic substance which forms _a cured resin layer, as mentioned above, SiO2 is preferable. In the wet method, a SiO ₂ film can be formed by coating silica sol or the like.

In this embodiment, as a forming material of the cured resin layers 21 and 22, you may use the resin in 1st Embodiment, the said inorganic substance, etc. combining suitably.

<Other embodiment>

In FIG. 2, although the case where the cured resin layer 2 is two layers is illustrated, the cured resin layer 2 may be three or more layers. Even when the cured resin layer 2 is three or more layers, the non-patterned portion (b) has at least the first cured resin layer 21 from the side of the transparent resin film 1 . The cured resin layer above the first layer may or may not be patterned.

3 : is sectional drawing which shows an example of the transparent conductive film of this embodiment. In addition, in FIG. 3, although it has demonstrated with the structure similar to FIG. 1, also in FIG. 3, of course, the structure similar to the structure demonstrated with FIG. 2 is applicable. The transparent conductive film of FIG. 3 is a case where it has the transparent conductive film 3 patterned via the cured resin layer 2 on both surfaces of the transparent resin film 1. In addition, although the transparent conductive film of FIG. 3 has the transparent conductive film 3 patterned on both sides, only one side may be patterned. Moreover, in the transparent conductive film of FIG. 3, although the pattern part (a) and the non-pattern part (b) of the patterned transparent conductive film 3 on both sides correspond, these do not need to coincide, and in various aspects It can be properly patterned on both sides. The same applies to other drawings.

Example

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, in each example, part and % are all based on weight.

《Example 1》

(Formation of cured resin layer)

10 parts of Adeca Filterera BUR-12A containing a rubber-modified epoxy resin (weight average molecular weight of the epoxy resin skeleton part: 2000) as a main component and 0.001 parts of Adeca Filterera BUR-12B, an antimony-based curing accelerator, are mixed, and this To the mixture, 90 parts of methyl isobutyl ketone was added to prepare a coating solution. The gelation time when the mixture was heated at 170° C. was 10 seconds. The coating solution is applied to one side of a transparent resin film made of a polyethylene terephthalate film (hereinafter referred to as PET film) having a thickness of 50 µm, and the coating film is dried (at 195°C for 1 minute) to have a thickness of 30 nm A phosphorus cured resin layer was formed.

About the measurement of the gelation time of a mixture, the amount of mixture was 2 g, and it measured according to "JIS C 6521 5.7 hardening time" except having set the specified temperature to 170 degreeC. That is, 2 g of the mixture was placed on a hot plate adjusted to 170°C, and time measurement was started. The contact circle motion was repeated immediately with a spatula, and the time until gelation was measured. During the contact circle motion, make sure that the mixture falls within the range of 25 mm in diameter, the spatula should not be lifted while the viscosity of the mixture is low, and when the viscosity rises, occasionally lift about 30 mm vertically from the hot plate,絲狀) was repeatedly performed this up-and-down movement until the thing broke. Curing time was made into until a filamentous thing breaks when a spatula is lifted from the time of putting a mixture on a hotplate. In addition, the contact circle motion was made at a speed of about 1 second per rotation. The measurement was repeated 3 times, and the average value was taken as the curing time (gelation time).

(Formation of transparent conductive film)

Next, on the cured resin layer, in an atmosphere of 0.4 Pa consisting of 98% of argon gas and 2% of oxygen gas, a reactive sputtering method using a sintered material of 90% by weight of indium oxide and 10% by weight of tin oxide is applied to a thickness of 20 A nanometer ITO film (refractive index of light 2.00) was formed, and the transparent conductive film was obtained.

(Patterning of ITO film)

After bonding the cellophane tape together so that it might be patterned in stripe shape on the said ITO film|membrane, this was immersed in 50 degreeC and 10 weight% hydrochloric acid (hydrogen chloride aqueous solution) for 10 minutes, and the ITO film|membrane was etched. The pattern width of the obtained ITO film was 6 mm, and the pattern pitch was 6 mm. Then, the cellophane tape was removed and patterning of the ITO film|membrane was performed.

(Crystallization of ITO film)

After etching the ITO film, heat treatment was performed at 140°C for 90 minutes to crystallize the ITO film, thereby producing a transparent conductive film in which the ITO film was patterned.

《Example 2》

In the formation of the cured resin layer, 10 parts of Adeca Filterera CRX-11 containing a rubber-modified epoxy resin (weight average molecular weight of the epoxy resin skeleton part: 2000) as a main component, and Adeca Filterera BUR- as an antimony curing accelerator A transparent conductive film was prepared in the same manner as in Example 1, except that a mixture of 0.001 parts of 12B was used. The gelation time of this mixture was 32 seconds.

《Example 3》

In the formation of the cured resin layer, 10 parts of Adeca Filterera CRX-10 containing a rubber-modified epoxy resin (weight average molecular weight of epoxy resin skeleton part: 2000) as a main component, and Adeca Filterera BU- as an antimony curing accelerator A transparent conductive film was prepared in the same manner as in Example 1, except that a mixture of 0.001 parts of 12B was used. The gelation time of this mixture was 28 seconds.

<Comparative Example 1>

In the formation of the cured resin layer, 10 parts of Adecafiltera CRX-6 containing an acrylic modified epoxy resin (weight average molecular weight of epoxy resin skeleton part: 500) as a main component, and a zinc-based curing accelerator (adekastab) A transparent conductive film was prepared in the same manner as in Example 1 except that 0.5 parts of the mixture was used. The gelation time of this mixture was 240 seconds.

<Comparative Example 2>

In the formation of the cured resin layer, 10 parts of Adeca Filterra CRX-5 containing an acrylic modified epoxy resin (weight average molecular weight of the epoxy resin skeleton part: 500) as a main component, and a zinc-based curing accelerator (adekastave) A transparent conductive film was prepared in the same manner as in Example 1 except that 0.5 parts of the mixture was used. The gelation time of this mixture was 99 seconds.

<Comparative Example 3>

In the formation of the cured resin layer, 10 parts of Adeca Filterera CRX-4 containing an epoxy resin (weight average molecular weight: 500) not subjected to modification treatment as a main component, and 0.5 parts of a zinc-based curing accelerator (adekastave) A transparent conductive film was prepared in the same manner as in Example 1 except that the mixed mixture was used. The gelation time of this mixture was 102 seconds.

<Comparative Example 4>

In the formation of the cured resin layer, 10 parts of ADECA FILTERA CRX-3 containing an epoxy resin (weight average molecular weight: 500) not subjected to modification treatment as a main component, and 0.5 parts of a zinc-based curing accelerator (adekastab) A transparent conductive film was prepared in the same manner as in Example 1 except that the mixed mixture was used. The gelation time of this mixture was 67 seconds.

The following evaluation was performed about the transparent conductive film (sample) of an Example and a comparative example. A result is shown in Table 1 or the text.

(1) thickness of each layer

Regarding what has a thickness of 1 micrometer or more, such as a transparent resin film, it measured with the Mitsutoyo microgauge type thickness meter. Thicknesses, such as a cured resin layer and an ITO film|membrane, were computed based on the waveform from an interference spectrum using MCPD2000 (brand name) which is an Otsuka Electronics Co., Ltd. instantaneous multi-photometric system.

(2) Surface elastic modulus of cured resin layer

The transparent conductive film was immersed in 50 degreeC and 10 weight% hydrochloric acid (hydrogen chloride aqueous solution) for 10 minutes, the ITO film|membrane was removed, and the cured resin layer was exposed. The surface elastic modulus of this cured resin layer was measured in the following procedure. Hysitron Inc. Manufacture, Triboindenter apparatus, and indenter used: Berkovich (triangular pyramid shape) was used, and measurement was performed at the temperature of 25 degreeC, and the indentation amount of 20 nm by the single indentation method.

(3) heat-and-moisture resistance

The surface resistance value (Ω/□) of the obtained crystalline transparent conductive layer was measured according to JIS K 7194 (1994) by a four-terminal method, and this was taken as the initial surface resistance value R0. Next, the surface resistance value R240 at the time of leaving to stand in the thermo-hygrostat (the SPEC company make, LHL-113) set to 85 degreeC and 85 %RH for 240 hours was measured. From these, R240/R0 was calculated|required as resistance change rate. The case where the resistance change rate was 1.5 or less was evaluated as "○", and the case where it exceeded 1.5 was evaluated as "x".

(4) Solvent resistance

After the prepared transparent conductive film was immersed in isopropanol at 25°C for 10 minutes, it was taken out, washed with pure water, and dried, and then the surface of the cured resin layer was visually observed. The case where there was no change in appearance was evaluated as "○", and the case where there was a change in appearance, such as roughening or discoloration, was evaluated as "x".

(5) alkali durability

After the prepared transparent conductive film was immersed in an alkali solution (5 wt%) at 50°C for 5 minutes, it was taken out, washed with pure water, and dried, and then the surface of the cured resin layer was visually observed. The case where there was no change in the appearance was evaluated as "○", and the case where there was a change in the appearance such as roughening or discoloration was evaluated as "x".

(6) the presence or absence of exudation of oligomers

The produced transparent conductive film was heat-processed at 160 degreeC for 2 hours, and the exudation of the oligomer from the cured resin layer at that time was confirmed visually. Evaluation was made on the basis of the following criteria.

(circle): The exudation of an oligomer was not confirmed.

(triangle|delta): The exudation of an oligomer was confirmed slightly.

x: The exudation of the oligomer was spread over a wide area.

From Table 1, it is confirmed that the transparent conductive film of an Example has the outstanding heat-and-moisture resistance, and can withstand use under high-temperature, high-humidity conditions.

1: Transparent resin film
2: cured resin layer
3: Transparent conductive film
4: adhesive layer
5: transparent gas
6: hard coat layer
a: pattern part
b: non-pattern part

Claims (7)

A transparent conductive film having a cured resin layer and a transparent conductive film in this order on a transparent resin film,
The cured resin layer is a cured product film obtained by curing a resin composition containing only an epoxy resin having a weight average molecular weight of 1500 or more and less than 5000 as an epoxy resin,
The thickness of the cured resin layer is 150 nm or less,
The transparent conductive film whose surface elasticity modulus of the said cured resin layer is 4 GPa or more and 12 GPa or less. The method of claim 1,
A transparent conductive film having a gelation time of 50 seconds or less when a mixture of the resin composition and the curing accelerator for the epoxy resin is heated at 170°C. 3. The method of claim 2,
The transparent conductive film in which the said hardening accelerator contains antimony. 4. The method according to any one of claims 1 to 3,
The transparent conductive film in which the said epoxy resin is a rubber-modified epoxy resin. 4. The method according to any one of claims 1 to 3,
The transparent conductive film whose saturation expansion coefficient in the temperature of 85 degreeC of the said cured resin layer, and the atmosphere of 85% of humidity is 0.5 % or less. 4. The method according to any one of claims 1 to 3,
The transparent conductive film is patterned,
The transparent conductive film whose change rate of the surface resistance value before and behind setting the said transparent conductive film in the atmosphere of 85 degreeC of temperature and 85% of humidity for 240 hours is 1.5 or less. The touch panel containing the transparent conductive film in any one of Claims 1-3.

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