KR20150089206A - Transparent conductive film for touch screen panel - Google Patents

Abstract

The present invention relates to a transparent conductive film for a touch screen panel, wherein the transparent conductive film has a transparent conductive layer formed on one surface of a plastic base film. An optical adjusting layer is disposed between the plastic base film and the transparent conductive layer, and an undercoating layer is disposed on a rear surface of the plastic base film, wherein transmittance of the transparent conductive film is 93% or more. The transparent conductive film according to the present invention is able to minimize a difference in a reflection rate between a pattern unit and a non-pattern unit so that a pattern shape is not shown. In addition, the high transparency of the present invention makes excellent appearance thereof, and the anti-blocking properties thereof are excellent, thus, a film can be easily wound.

Description

TRANSPARENT CONDUCTIVE FILM FOR TOUCH SCREEN PANEL FOR TISSUE SCREEN PANEL

The present invention relates to a transparent conductive film for a touch screen panel, and more particularly to a transparent conductive film for a touch screen panel, which includes an optical adjustment layer between a plastic substrate film and a transparent conductor layer, thereby minimizing a reflectance difference between a pattern portion and non- And a transparent conductive film for a touch screen panel which is easy to take up the film by imparting fine unevenness to the optical adjusting layer and the undercoat layer and having high transparency and excellent appearance by including an undercoat layer on the other surface, .

The touch screen panel is a panel that does not use an input device such as a keyboard or a mouse but detects a character or a specific position of the screen (screen) when a human hand or an object touches the position and processes a specific function. The touch screen to which the touch screen panel is applied is widely used in mobile terminals such as mobile phones and navigation devices because it is portable and intuitive and easy to operate.

The touch screen panel basically consists of a touch screen panel, a controller, and a driver SW. The touch screen panel consists of a top plate (film or glass) on which an ITO (Indium Tin Oxide) film is deposited, detects the presence of contact input, detects input coordinates, and transmits signals to the controller . In the case of the controller, the function of converting the signal transmitted from the touch screen panel to the digital signal and outputting it as coordinates on the display, and the driver SW is a program for receiving the digital signal received from the controller and implementing the touch screen panel according to each operating system . Touch screen panels are classified into Resistive, Capacitive, Surface Accoustic Wave (SAW), and Infrared (IR) depending on the implementation method. Recently, in terms of durability and transmittance A capacitance type having excellent characteristics has been attracting attention.

The touch panel of the capacitive type includes a touch pattern layer. The touch pattern layer serves to generate an electrical signal corresponding to external physical contact. To detect an input position, the touch pattern layer includes a transparent conductive layer And is used after being subjected to predetermined patterning. As the difference between the average reflectance of the pattern portion and the non-pattern portion increases in patterning the transparent conductor layer, the pattern shape is visually confirmed more easily, resulting in poor appearance characteristics as a display element. In particular, since the ITO film is used for the surface layer in the case of the capacitance type, the pattern visibility directly affects the appearance of the product, and development is underway to improve the appearance.

Patent Document 1 proposes a method of making the pattern shape difficult to be seen by laminating the pressure-sensitive adhesive layer on the patterned transparent conductive film. However, it is difficult to make the pattern shape difficult to be completely seen by the above method, and when the application of the pressure- The pattern shape in the transparent conductive film becomes easy to see.

According to Patent Document 2, there is proposed a method in which a low refractive index layer and a high refractive index layer are sequentially laminated between a transparent film base and a transparent conductor layer to make the pattern shape difficult to see. However, when the undercoat layer is not included on the other side, The oligomer is precipitated in the base film and the transparency and appearance of the transparent conductive film may be deteriorated.

Patent Document 3 proposes a method of including a transparent thin film having a refractive index lower than that of the transparent conductor layer in the transparent conductor layer in order to improve the transparency of the transparent conductive film. However, when the above method is applied, It becomes difficult to apply it to a capacitance method.

Japanese Laid-Open Patent Publication No. 2013-116992 Japanese Laid-Open Patent Publication No. 2013-180551 Korean Patent Publication No. 1243725

An object of the present invention is to provide a transparent conductive film which can minimize the difference in reflectance between the pattern portion and the non-pattern portion of the conductive optical film to make the pattern shape difficult to see, has high transparency and excellent appearance, .

In the present invention, in a transparent conductive film having a transparent conductor layer formed on one side of a plastic base film, an optical adjustment layer is positioned between the plastic base film and the transparent conductor layer, an undercoat layer is located on the back side of the plastic base film, A transparent conductive film for a touch screen panel having a conductive film having a transmittance of 93% or more.

The optical adjustment layer is formed by sequentially laminating an oligomer-preventing layer and a middle refractive layer on a base film.

The oligomer-preventing layer preferably has a thickness of 40 to 5,000 nm.

Preferably, the medium refractive index layer has a refractive index of 1.43 to 1.50 and a thickness of 10 to 60 nm.

It is preferable that the medium refractive index layer contains inorganic fine particles and the average particle diameter of the particles is 10 to 40 nm.

It is preferable that the optical adjustment layer and the undercoat layer have fine irregularities on the surface and the arithmetic mean roughness (Ra) is 2 to 30 nm.

The undercoat layer preferably has a refractive index of 1.30 to 1.46 and a thickness of 60 to 120 nm.

The undercoat layer may include hollow or porous silica fine particles, and the average particle size of the particles is preferably 40 to 110 nm.

The surface of the transparent conductive film facing the undercoat layer preferably has an average specular reflectance of 0.1 to 3% at an incident angle of 5 ° in the wavelength region (380 nm? 780 nm) of the visible light.

It is preferable that the average reflectance difference? R of the transparent conductor layer pattern portion (a) and the non-pattern portion (b) is 2% or less.

The transparent conductive film according to the present invention minimizes the difference in reflectivity between the pattern portion and the non-pattern portion, thereby preventing the pattern shape from being seen, providing excellent appearance due to high transmittance, and excellent anti-blocking property.

1 is a schematic cross-sectional view of a transparent conductive film 10 according to an embodiment of the present invention,
2 is a schematic cross-sectional view of an optical adjusting layer 12 constituting a transparent conductive film according to an embodiment of the present invention.

Hereinafter, the transparent conductive film of the present invention will be described with reference to the accompanying drawings.

1 is a schematic cross-sectional view of a transparent conductive film according to an embodiment of the present invention. 1, the transparent conductive film 10 according to the present invention has a transparent conductive layer 14 laminated on a curable resin laminate 1, and the cured resin laminate 1 has a base film 11, An optical adjustment layer 12 formed on one surface of the base film, and an undercoat layer 13 formed on the back surface of the base film.

2 is a schematic cross-sectional view of an optical adjustment layer 12 according to an embodiment of the present invention.

As shown in Fig. 2, the optical adjustment layer 12 according to the present invention includes an undercoat layer 12a and a medium refractive layer 12b.

1. A base film (11)

The base film functions to support the optical adjustment layer, the undercoat layer, and the like according to the present invention. The base film preferably has a high light transmittance and a low haze value for use as a display device. For example, the light transmittance at a wavelength of 400 to 800 nm is preferably 40% or more, more preferably 60% or more, and the haze value is preferably 5% or less, more preferably 3% or less. When these conditions are not satisfied, the sharpness of the image tends to be lacking when used as the display member. In order to exhibit this effect, the upper limit of the light transmittance is about 99.5%, and the lower limit of the haze value is about 0.1%.

The material of the base film 11 is not particularly limited as long as it satisfies the above-mentioned conditions, and can be appropriately selected from resin materials used for known plastic base films. As such a resin material for a base film, there can be used, for example, an ester, an ethylene, a propylene, a diacetate, a triacetate, a styrene, a carbonate, a methylpentene, a sulfone, an ether ethyl ketone, an imide, a fluorine, a nylon, A polymer or a copolymer polymer having one structural unit selected from the group consisting of a polymer and a copolymer. Among these resins, a polymer or a copolymer polymer having one constituent unit selected from an ester type such as polyethylene terephthalate, an acetate type such as triacetyl cellulose and an acrylate type such as polymethyl methacrylate is preferable, They are excellent in transparency, strength and uniformity of thickness.

Particularly, a base film made of a polymer having an ester system as a constituent unit is particularly preferable in terms of transparency, haze value, and mechanical properties. Examples of such polyester resins include polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polyethylene-a,? -Bis (2-chlorophenoxy) ethane-4,4'-dicarboxyl And the like. These polyesters may also be copolymerized if the other dicarboxylic acid component or diol component is 20 mol% or less. Among them, polyethylene terephthalate is particularly preferable when it is judged comprehensively with regard to quality, economical efficiency and the like. These constituent resin components may be used alone or in combination of two or more.

Although the thickness of the base film 11 is not particularly limited, it is usually 5 to 800 占 퐉, preferably 10 to 250 占 퐉 in terms of transparency, haze value, and mechanical properties. Further, two or more films may be bonded by a known method.

The plastic base film 11 may be subjected to various surface treatments, for example, corona discharge treatment, glow discharge treatment, flame treatment, etching treatment or roughening treatment. In order to promote adhesion, a primer layer such as a polyurethane, polyester, polyester acrylate, polyurethane acrylate, polyepoxyacrylate, or titanate compound may be applied to the surface of the plastic substrate film After coating, a high refractive index hard coat layer may be formed. Particularly, when a primer is applied to a composition comprising a copolymer obtained by crosslinking an acrylic compound with a hydrophilic group-containing polyester resin and a crosslinking agent, adhesion is improved and durability such as heat resistance and water resistance is excellent, .

2. An oligomer-preventing layer 12a of the optical adjustment layer 12

The oligomer prevention layer 12 may be formed on one side of the base film 11 of the transparent conductive film 10 according to the present invention in order to crystallize the transparent conductive film 14 of the transparent conductive film, The oligomer capable of depositing from the base film 11 is blocked to prevent the appearance of the transparent conductive film from deteriorating.

The oligomer-preventing layer 12a may be composed of a single layer or a plurality of layers according to an optical design method, and the refractive index in the single or plural layers is preferably made to coincide with the refractive index of the base layer, It is not.

On the other hand, the oligomerization preventing layer 12a is formed by applying an ionizing radiation curable resin, a photopolymerization initiator, refractive index controlling inorganic fine particles and a solvent, and then curing the ionizing radiation curable resin composition. When high refractive index characteristics are required according to the optical design, May be included in the ionizing radiation curable resin composition to realize a single or plural oligomer preventing layers 12a having a refractive index to be designed.

The composition of the ionizing radiation curable resin composition will be described specifically.

2-1. Ionizing radiation curable resin

The ionizing radiation curable resin, which is a component added to the ionizing radiation curable resin composition of the present invention, includes an ultraviolet curable resin and functions to impart abrasion resistance to the coating film.

The ionizing radiation curable resin preferably contains a skeleton structure of a (meth) acrylic resin, an epoxy acrylic resin, a polyurethane resin, a polyester resin, a polyether resin, an olefin resin and a polyimide resin, Polymer oligomers of 3 to 10 are used. More specifically, as the resin containing the (meth) acrylic resin in the skeleton structure, a resin obtained by polymerization or copolymerization of a (meth) acrylic monomer, a resin obtained by copolymerizing a (meth) acrylic monomer and a monomer having an ethylenic unsaturated double bond have.

As the resin containing the polyurethane resin in the skeleton structure, there is a resin containing a urethane bond in the molecular chain.

The resin containing the polyester resin in the skeleton structure includes an unsaturated polyester resin, an alkyd resin, and a polyethylene terephthalate as a resin containing an ester bond in the molecular chain.

Resins containing the polyether resin in the skeleton structure include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol as resins containing an ether bond in the molecular chain.

Examples of the resin containing the olefin resin in the skeleton structure include polyethylene, polypropylene, ethylene and a propylene copolymer, ethylene and a vinyl acetate copolymer, an ionomer, ethylene and a vinyl alcohol copolymer, and ethylene and a vinyl chloride copolymer .

The resin containing the polyimide resin in the skeleton structure may be a copolymer comprising an imide bond in the molecular chain and a copolymer comprising two or more of the above skeleton structures or a copolymer comprising the skeleton structure and other monomers .

The ionizing radiation curable resin may further contain a multifunctional monomer or a multifunctional oligomer for improving the curing degree of the composition. For this purpose, a multifunctional functional group containing three or more functional groups is preferable.

Specifically, the polyfunctional monomer may be a reaction product of a (meth) acrylate and a polyhydric alcohol, and specifically, pentaerythritol triacrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (Meth) acrylate, trimethylolpropane tri (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate.

The polyfunctional oligomer may be a urethane (meth) acrylate oligomer or a polyester (meth) acrylate oligomer. The polyfunctional oligomer may be a copolymer comprising at least one kind of monomer or a monomer different from the oligomer, Is 3 to 10 and can be used in copolymerization with a low molecular weight water having a weight average molecular weight of less than 8,000.

2-2. Photopolymerization initiator

The photopolymerization initiator, which is a component added to the ionizing radiation curable resin composition of the present invention, is capable of decomposing by ultraviolet rays and has a function of initiating the reaction of the ultraviolet curable resin.

The photopolymerization initiator to be used in the present invention is not particularly limited and may be selected from the group consisting of benzophenones, acetophenones, hydroxycyclohexyl phenyl ketones, thioxanthones, dibenzyl disulfites, diethyl oxides, triphenyl biimidazoles, N, N-methylaminobenzoate may be used.

At this time, the content of the photopolymerization initiator is included in the solid content of the resin composition in an amount of 0.1 to 10% by weight. When the content is less than 0.1% by weight, there is a problem that the photopolymerization is insufficient. When the content exceeds 10% There is no problem in curing, but when left standing for a long time by the remaining initiator, an initiator may precipitate on the surface and the properties of the cured resin layer may change.

2-3. Inorganic fine particles for adjusting refractive index

The ionizing radiation curable resin composition may contain inorganic fine particles when high refractive index characteristics are required according to the optical design.

The inorganic fine particles contained in the ionizing radiation curable resin mixture are selected from the group consisting of titanium oxide, zirconium oxide, and alumina, which are high refractive index fillers, and are preferably at least one.

The average particle diameter of the inorganic fine particles is preferably from 1 to 120 nm, more preferably from 1 to 60 nm, even more preferably from 2 to 40 nm. This range is preferable because it reduces haze and improves dispersion stability and adhesion to the upper layer by appropriate irregularities on the surface.

2-4. menstruum

The entire solid content including the ionizing radiation curable resin, the photopolymerization initiator, and the inorganic fine particles may be diluted in an appropriate solvent and prepared into a coating composition liquid having a hometown content of 5 to 50 wt%, and then applied to the plastic base film 11. Examples of the solvent used in the coating composition liquid include ketones, esters, aliphatic hydrocarbons, halogenated hydrocarbons, aromatic hydrocarbons, amines, water, alcohols and the like, And particularly preferably one or more selected from the group consisting of toluene, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monoethyl ether and cyclohexanone may be mixed and used.

2-5. Coating and curing

The oligomer prevention layer 12a may be formed by applying a coating composition liquid onto the plastic substrate film and then curing the coating composition liquid. The application of the coating composition liquid A known method such as comma coating, lip coating, roll coating, gravure coating, blade coating, wire bar coating, reverse coating, Can be selected.

On the other hand, the curing can be applied to electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams and radiation (alpha rays, beta rays, gamma rays, etc.) and is practically preferable because of ultraviolet rays.

On the other hand, the thickness of the oligomer prevention layer 12a is preferably 40 to 5,000 nm. When the thickness is less than 40 nm, the oligomer is precipitated from the base film 11 at a high temperature and the transparent conductive film is blurred to degrade the appearance of the film. When the thickness exceeds 5,000 nm, the coating layer becomes hard, There is a problem in that cracks are generated in the resin, resulting in a problem that the flexibility is lowered.

3. The medium-refraction layer 12b of the optical adjustment layer 12,

In forming the optical adjustment layer 12 on one side of the base film 11 of the transparent conductive film 10 according to the present invention, the optical adjustment layer 12 includes a medium refractive layer 12b, The layer 12b is located between the transparent conductive layer 14 and the oligomeric anti-reflective layer 12a, and the middle refractive layer 12b minimizes the reflectance difference between the pattern portion and the non-pattern portion of the transparent conductive layer by controlling the refractive index, It plays a role of not seeing.

The refractive index of the middle refractive layer 12b of the optical adjustment layer 12 is preferably 1.43 to 1.50. When the refractive index is less than 1.43 or more than 1.50, it is not suitable for the optical design for minimizing the reflectance difference between the pattern portion and the non-pattern portion of the transparent conductive layer, so that the function as the optical adjustment layer can not be sufficiently exhibited, There is a problem.

The thickness of the middle refractive layer 12b is preferably 10 to 60 nm. If the thickness is out of the above range, it may not conform to the design of the optical adjustment layer, and the problem of the pattern shape may be recognized.

On the other hand, the middle refractive layer 12b of the optical adjustment layer 12 is formed by applying an ionizing radiation curable resin composition containing an ionizing radiation curable resin, a photopolymerization initiator, an inorganic fine particle and a solvent, and curing it, The refractive index can be adjusted by including inorganic fine particles, and fine irregularities are formed on the surface of the optical adjustment layer 12, thereby realizing excellent anti-blocking property.

The ionizing radiation curable resin composition for forming the refraction layer 12b in this case will be described specifically for each composition.

3-1. Ionizing radiation curable resin

An ionizing radiation curable resin can be applied in the same manner as in 2-1 above.

3-2. Photopolymerization initiator

A photopolymerization initiator can be applied in the same manner as in 2-2 above.

3-3. Refractive index adjustment and inorganic fine particles for forming concave and convex

The inorganic fine particles to be added to the ionizing radiation curable resin composition of the present invention are those which are capable of adjusting the refractive index of the middle refractive layer of the optical adjustment layer 12 and forming fine irregularities on the surface of the cured resin layer to impart anti- Function.

In order to realize this object, the inorganic fine particles contained in the middle refractive layer 12b of the optical adjustment layer 12 are generally silica particles, and in the embodiments of the present invention, silica particles are used. It will not be limited.

The inorganic fine particles contained in the middle refractive layer 12b of the optical adjustment layer 12 preferably have an average particle diameter of 10 to 40 nm. When the inorganic fine particles are not included, the surface irregularities are not formed. Therefore, the anti-blocking property is not sufficient. If the inorganic fine particles are not contained, the anti-blocking property is insufficient. have.

In addition, the inorganic fine particles may be surface-treated with an organic compound such as a silane coupling agent, a polyol, an alkylol amine, or a titanate coupling agent to facilitate dispersion.

At this time, the inorganic fine particles are not particularly limited, and any of spherical, cubic, spindle-shaped, and indefinite shapes can be used.

3-4. Solvent, application and curing

Solvents can be applied in the same manner as in 2-4 and 2-5.

On the other hand, when the refractive index of the medium refractive layer is 1.43 to 1.53, the thickness of the medium refractive layer is preferably 10 to 60 nm, and when the thickness is less than 10 nm or more than 60 nm, There is a problem that the pattern shape of the entire transparency layer is visually recognized.

4. Undercoat layer 13

The undercoat layer 13 is formed on the back surface of the base film 11 corresponding to the transparent conductive layer 14 of the transparent conductive film 10 according to the present invention to improve the high transparency and anti-blocking property of the transparent conductive film.

The refractive index of the undercoat layer 13 is preferably 1.30 to 1.46. When the refractive index of the undercoat layer is less than 1.30, the material selection is limited. When the refractive index of the undercoat layer is more than 1.46, the optical design is not suitable for realizing the high transparency characteristic in the present invention.

On the other hand, the middle refractive layer of the optical adjustment layer 12 and the undercoat layer 13 formed on the back surface of the base film 11 are composed of an ionizing radiation curable resin, a photopolymerization initiator, an ionizing radiation curing type The refractive index can be adjusted by including the inorganic fine particles and high permeability and high hardness characteristics by being formed by applying and curing the resin composition and fine irregularities are formed on the surfaces of the optical adjustment layer 12 and the undercoat layer 13, Thereby realizing blocking property.

The composition of the ionizing radiation curable resin composition will be described specifically.

4-1. Ionizing radiation curable resin

An ionizing radiation curable resin can be applied in the same manner as in 2-1 above.

4-2. Photopolymerization initiator

A photopolymerization initiator can be applied in the same manner as in 2-2 above.

4-3. Inorganic fine particles

As the inorganic fine particles contained in the undercoat layer 13, hollow or porous silica fine particles are used (hereinafter referred to as hollow fine particles). The refractive index of the hollow microparticles is preferably 1.40 or less, more preferably 1.24 to 1.38, and most preferably 1.28 to 1.36. The hollow fine particles are preferably hollow silica particles, and the inorganic fine particles are described below with reference to hollow silica particles. The refractive index used here represents the refractive index of the whole particles and does not represent the refractive index of only silica as the outer shell forming the hollow silica particles. Assuming that the radius of the cavity inside the particle is a and the radius of the outer shell of the particle is b, the porosity x represented by the following equation (1) is preferably 10 to 60%, more preferably 20 to 60% , And most preferably 30 to 60%.

Equation (1): x = (4πa 3/3) (4πb 3/3) × 100

If the above hollow silica particles are intended to have a lower refractive index and a higher porosity, the thickness of the outer shell is thinned and the strength as a particle is lowered. Therefore, particles having a refractive index within the above-mentioned range from the viewpoint of scratch resistance are preferable.

On the other hand, the refractive index of the hollow silica particles can be measured by an Abbe refractometer (manufactured by ATAGO K.K.). A hollow silica particle already known in Japanese Laid-Open Patent Publication Nos. 2001-233611 and 2002-79616 and commercially available hollow silica particles can also be used.

The hollow microparticles preferably have an average particle size of 40 to 110 nm. When it is within the above range, the ratio of the cavity can be satisfactorily maintained and the refractive index can be sufficiently reduced. The shape is most preferably spherical, but it may be cubic, spindle-shaped, or irregular. Wherein the average particle diameter of the hollow silica particles can be determined from electron micrographs.

In addition, the inorganic fine particles may be surface-treated with an organic compound such as a silane coupling agent, a polyol, an alkylol amine, or a titanate coupling agent to facilitate dispersion.

4-4. Solvent, application and curing

Solvents can be applied in the same manner as in 2-4 and 2-5.

On the other hand, the thickness of the undercoat layer 13 applied to the back surface of the base film 11 is preferably 60 to 120 nm, and when the thickness of the undercoat layer is less than 60 nm or exceeds 120 nm, There is a problem that it is difficult to achieve a high transparency and a transparent conductive film.

On the other hand, the oligomer-preventing layer 12a and the medium refractive layer 12b of the optical adjustment layer 12, which are sequentially formed on the surface of the base film 11 facing the transparent conductive layer 14, The undercoat layer 13 to be formed is formed by applying an ionizing radiation curable resin mixture to the plastic base film 11 and then formed by curing. Examples of the active ray include ultraviolet rays, electron rays and radiation (a line, ) Can be applied, and ultraviolet rays are practically useful because they are easy to use.

5. Transparency layer (14)

The transparent conductive layer 14 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO) a conductive electrode film is deposited using a conductive compound selected from the group consisting of a conductive nano wire, a carbon nanotube (CNT), and a silver nano wire, and is then formed into a transparent conductive electrode pattern layer by photolithography, etching, or laser processing It is. The transparent conductive layer typically has a thickness of 10 to 50 nm and a refractive index of 1.9 to 2.1.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is intended to more specifically illustrate the present invention, and the scope of the present invention is not limited to these embodiments.

< Example 1 >

(1) Formation of optical adjusting layer

(1-1) Formation of oligomer-preventing layer

(Lamier QTD0, product of Toray Co., Ltd.) having a thickness of 100 탆 was coated with a paint (solid content 40%) (PELNOX product, XJA-0197-65, refractive index (n) = 1.65) containing polyfunctional acrylic resin and zirconium oxide. of by irradiating a high-refraction adhesive layer surface (with a refractive index (n) = 1.65) after two minutes drying the coating using a micro-gravure coater, and 80 ℃, the accumulated light quantity of the high pressure mercury ultraviolet lamp 300mJ / cm ² to cure the coating layer An oligomer prevention layer having a thickness of 1 mu m was formed.

(1-2) Formation of refraction layer

(PELNOX product, XJA-0262-48, refractive index (n) = 1.48, average particle diameter of silica particles: 20 nm) containing polyfunctional acrylic resin and silica fine particles was diluted with propylene glycol monomethyl ether, Solution was coated on the oligomer-preventing layer using a micro gravure coater, dried at 80 ° C for 2 minutes, and irradiated with a cumulative light quantity of 300 mJ / cm ² of a high-pressure mercury ultraviolet lamp to cure the coating layer To form a refractive index intermediate layer of 40 nm.

(2) Formation of undercoat layer

(%) (Solid content: 5.5%) (Catalystable product, ELCOM series, refractive index (n) = 1.38, hollow silica average particle diameter: 60 nm) was diluted with propylene glycol monomethyl ether to obtain a 2% solution (The middle refractive index was coated on the adhesive layer side (refractive index (n) = 1.58) using a micro gravure coater, and the coating solution was applied to the base film at 80 DEG C for 2 minutes After drying, the coated layer was cured by irradiating an accumulated light quantity of 300 mJ / cm ² with a high-pressure mercury ultraviolet lamp to form an undercoat layer of 100 nm.

(3) Formation of transparent conductor layer

An ITO transparent conductor layer (refractive index (n) = 2) having a thickness of 20 nm was formed on the optical adjustment layer using a sintered body having a weight ratio of indium oxide and tin oxide of 95: 5 using a sputtering method. The transparent conductive film on which the ITO transparent conductor layer was formed was heat-treated at a temperature of 150 ° C for 40 minutes to prepare a transparent conductive film having the ITO transparent conductor layer crystallized.

(4) patterning by etching of the transparent conductor layer

A photoresist patterned in a stripe pattern on a transparent conductive layer of a transparent conductive film was coated, dried and cured, and then dipped in 5% hydrochloric acid (hydrogen chloride aqueous solution) at 25 캜 for 1 minute to etch the ITO film

< Example  2>

A transparent conductive film was produced in the same manner as in Example 1, except that the undercoat layer had a thickness of 80 nm in the process of manufacturing the undercoat layer of Example 1.

< Example  3>

A transparent conductive film was prepared in the same manner as in Example 1, except that the thickness of the oligomer-preventing layer was 50 nm in the process of producing the anti-oligomer layer of Example 1.

< Comparative Example  1>

A transparent conductive film was produced in the same manner as in Example 1 except that the oligomer-preventing layer of Example 1 was omitted.

< Comparative Example  2>

A transparent conductive film was prepared in the same manner as in Example 1 except that the thickness of the oligomer-preventing layer was 6.5 mu m in the process of manufacturing the anti-oligomer layer of Example 1. [

< Comparative Example  3>

A transparent conductive film was produced in the same manner as in Example 1 except that the medium refractive layer in Example 1 was omitted.

< Comparative Example  4>

A transparent conductive film was prepared in the same manner as in Example 1, except that the thickness of the medium refractive layer was 100 nm in the medium refractive layer manufacturing process of Example 1.

< Comparative Example  5>

(Refractive index (n) = 1.52) was diluted with propylene glycol monomethaldehyde to prepare a 2% solution of acrylic resin paint (solid content 45%) (KKPC, Guardia-3620, refractive index And the coating liquid obtained was used in place of the coating liquid.

< Comparative Example  6>

A transparent conductive film was produced in the same manner as in Example 1 except that the undercoat layer of Example 1 was omitted.

< Comparative Example  7>

In the undercoating layer manufacturing process of Example 1, a polyfunctional acrylic resin coating material (solid content 45%) (Guardia-3620, refractive index n = 1.52) was diluted with propylene glycol monomale ether, The procedure of Example 1 was repeated except that the coating liquid obtained was used

< Comparative Example  8>

The procedure of Example 1 was repeated except that the thickness of the undercoat layer was 30 nm in the process of manufacturing the undercoat layer of Example 1

< Comparative Example  9>

The procedure of Example 1 was repeated except that the undercoat layer had a thickness of 150 nm in the undercoat layer manufacturing process of Example 1

< Experimental Example >

1. Measurement of haze and permeability

The haze and the transmittance of the cured resin laminate (1) were measured according to the measuring methods of JIS K 7136 and JIS K 7361 using Nippon Denshoku NDH-5000 (D65 / 10 °) and are shown in Tables 1 and 2 below.

2. Oligomer measurement

The cured resin laminate 1 was heat-treated at a temperature of 150 ° C for 1 hour, and then the haze was measured using a spectrophotometer (haze after heat treatment) / (change in haze before heat treatment).

3. Arithmetic mean illuminance (Ra)

The surface roughness of the optical adjustment layer 12 and the undercoat layer 13 of the curable resin laminate 1 was measured using an atomic force microscope to measure an arithmetic average roughness Ra at 10 탆 X 10 탆, 1.

4. Anti-blocking property measurement

Curable resin laminate (1) of a 10 × 15cm cut to size, fit the optical adjustment layer 12 and the undercoat layer 13 on the superposed glass plates, the blocking from 200g / cm ² condition to the naked eye and left for 24 hours at room temperature the phenomenon of Respectively.

5. Measurement of Flexibility

And measured according to JIS K5400 standard using a flexural tester (cylindrical mandrel), and is shown in Table 1 below.

6. Measurement of surface reflectance and mean reflectance difference

The surface reflectance was measured with a UV spectrophotometer (Shimazu UV-PC3600) equipped with an adapter at an incident angle (= reflection angle) of 5 ° in the visible light wavelength range (380 to 780 nm) Using a matte paint, the surface reflectance was measured after backside treatment with black.

The undercoat layer 13 of the transparent conductive film was measured for the average reflectance and the transparent conductive layer 14 had an average reflectance difference (? R =? Non-pattern portion-pattern portion) between the pattern portion (a) ) Were measured.

7. Pattern visibility

The pattern visibility of the transparent conductive film was evaluated based on whether or not the transparent conductive layer was on the flat black plate and the white plate and whether the pattern portion and the non-pattern portion could be distinguished from each other by the naked eye.

◎: There is no difference between pattern part and non-pattern part

○: There is little difference between pattern part and non-pattern part

X: The difference between the pattern part and the non-pattern part is clear

Test Items Example Comparative Example One 2 3 One 2 Curable resin laminate Permeability (%) 93.58 93.44 93.61 93.48 93.56 Haze (%) 0.60 0.67 0.71 0.58 0.60 My oligomeric nature 1.03 1.04 1.18 1.82 1.02 Anti-blocking property O O O O O Flexural strength (mm) 4 4 2 2 16 Undercoat layer Arithmetic Surface Roughness (nm) 13.5 15.3 15.1 14.3 15.6 Average reflectance (%) 1.73 2.79 1.70 1.75 1.76 The optical adjustment layer Arithmetic mean illuminance (nm) 3.7 3.5 3.2 4.3 3.7 Transparency layer The reflectance difference (? R) 0.61 0.73 0.69 0.75 0.69 Pattern visibility ◎ ◎ ◎ ◎ ◎

Comparative Example 3 4 5 6 7 8 9 91.19 95.24 94.01 90.58 91.04 91.25 91.89 0.63 0.70 0.45 1.1 0.35 0.75 0.69 1.03 1.03 1.01 2.72 1.02 2.15 1.03 X O X O X O O 4 4 4 4 4 4 4 14.3 15.1 15.5 4.2 0.8 17.3 14.2 1.75 1.69 1.71 4.89 4.67 3.91 3.82 0.8 4.2 0.9 3.8 3.7 4.1 4.4 2.6 2.7 1.8 0.78 0.68 0.71 0.74 X X O ◎ ◎ ◎ ◎

According to the above results, the films prepared in Examples 1 to 3 were found to minimize the difference in reflectance between the pattern portion and the non-pattern portion of the transparent conductive optical film, making the pattern shape hard to be seen and having high transmittance, excellent appearance, The physical properties were confirmed. On the other hand, in Comparative Example 1 in which the oligomer-preventing layer was omitted, the oligomer resistance was poor, and in Comparative Example 2 in which the oligomer-preventing layer was more than 5,000 nm, the flex resistance was poor. In Comparative Example 3 in which the medium refractive index layer of the optical adjustment layer was omitted, the anti-blocking property and the pattern visibility were poor, and in Comparative Example 4 in which the medium refractive index was more than 40 nm, the function as the optical adjustment layer was not exhibited and the pattern visibility was poor , And the anti-blocking property of Comparative Example 5 in which silica particles were excluded from the middle refractive layer was poor. In Comparative Example 6 in which the undercoat layer located on the back surface of the base film was excluded, the oligomer and permeability were poor, and in Comparative Example 7 in which the hollow silica particles were excluded from the undercoat layer, the permeability and anti- In Comparative Example 8 in which the thickness of the undercoat layer was 60 nm or less was poor in transmittance and poor oligomericity, and in Comparative Example 9 in which the thickness of the undercoat layer was 120 nm or more, the transmittance was poor.

The high transparency conductive film having excellent pattern visibility of the invention can be used for an index matching film for a touch panel.

10. Transparent conductive film 1. Curable resin laminate
11. Base film 12. Optical adjustment layer
12a. The oligomer-preventing layer 12b. Middle refractive layer
13. Undercoat layer
a. Pattern part b. The non-

Claims (10)

A transparent conductive film having a transparent conductor layer formed on one surface of a plastic base film, wherein an optical adjustment layer is positioned between the plastic base film and the transparent conductor layer, an undercoat layer is located on the back surface of the plastic base film, A transparent conductive film for a touch screen panel having a transmittance of 93% or more. The transparent conductive film according to claim 1, wherein the optical adjustment layer is formed by sequentially laminating an oligomer-preventing layer and a medium-refraction layer on a base film. The transparent conductive film according to claim 2, wherein the anti-oligomer layer has a thickness of 40 to 5,000 nm. The transparent conductive film according to claim 2, wherein the medium refractive index layer has a refractive index of 1.43 to 1.50 and a thickness of 10 to 60 nm. The transparent conductive film according to claim 2, wherein the medium refractive index layer contains inorganic fine particles and the average particle diameter of the particles is 10 to 40 nm. The transparent conductive film according to claim 1, wherein the optical adjustment layer and the undercoat layer have fine irregularities on the surface and an arithmetic mean roughness (Ra) of 2 to 30 nm. The transparent conductive film according to claim 1, wherein the undercoat layer has a refractive index of 1.30 to 1.46 and a thickness of 60 to 120 nm. The transparent conductive film according to claim 1, wherein the undercoat layer comprises hollow or porous silica fine particles and the particles have an average particle size of 40 to 110 nm. The transparent conductive film according to claim 1, characterized in that the surface of the transparent conductive film facing the undercoat layer has an average specular reflectance of 0.1 to 3% at an incident angle of 5 ° in the wavelength region (380 nm? 780 nm) of visible light By weight. The transparent conductive film according to claim 1, wherein the average reflectance difference? R of the transparent conductor layer pattern part (a) and the non-pattern part (b) is 2% or less.

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