KR20190123081A - Transparent conductive film - Google Patents

Abstract

The present invention relates to a transparent conductive film. The present invention relates to the transparent conductive film comprising a transparent film base layer made of an organic polymer film and a transparent conductive layer made of a metal oxide. In the transparent conductive film, a titanium oxide (TiO_2) is formed by depositing a titanium (Ti)-based oxide between the transparent film base layer and the transparent conductive layer such that the present invention provides the transparent conductive film which maintains high transparency and improves an adhesion strength between the layers, thereby providing excellent adhesion strength and chemical resistance even in contact with chemicals, and can usefully be used as films for a touchscreen panel.

Description

Transparent conductive film {TRANSPARENT CONDUCTIVE FILM}

The present invention relates to a transparent conductive film, and more particularly, to a transparent conductive film comprising a transparent conductive layer made of a metal oxide on a transparent film base layer made of an organic polymer film, wherein the transparent film base layer and the transparent conductive layer By including a titanium oxide (TiO ₂ ) layer formed by depositing a titanium (Ti) -based oxide in the, it relates to a transparent conductive film with improved bonding strength and chemical resistance between each layer while maintaining high transparency.

Conventionally, the conductive glass of the form which formed the indium oxide thin film on the glass substrate as a transparent conductive member has been mainly used. However, since glass is used as a substrate, there is a difficulty in applying it to various applications due to inferior processability and flexibility. For this reason, in recent years, the use of plastic base materials including polyethylene terephthalate, cycloolefin, polycarbonate, etc., which are excellent in impact resistance and lightweight, in addition to workability and flexibility, has become common.

In general, a transparent conductive film is formed on a plastic film with a compound having a low specific resistance in a thin film form, and the application examples thereof include liquid crystal displays, flat panel displays such as EL displays, and transparent and electrical electrodes in touch panels. Mainly used for various purposes.

In addition, the demand for transparent conductive films with low specific resistance and high transmittance is increasing due to the increase in size of the display and the need for high transparency.

In the transparent conductive film, indium tin oxide (ITO) is mainly used for the transparent conductive layer, which is generally formed through sputtering, which is a dry coating method. In the sputtering method, a gas for plasma formation is introduced into a chamber in a vacuum state, and a thin film constituent material is formed on a film by colliding with a target through application of electric power.

On the other hand, the substrate and the wet coating layer may undergo thermal damage and cause outgassing of hydrogen, oxygen, etc., including moisture, thereby preventing normal growth and crystallization of the transparent conductive layer. This not only prevents growth in proportion to the applied power, but also causes deformation of the crystal structure, which may adversely affect overall physical properties such as surface resistance, light transmittance, color difference, and reflectance of the transparent conductive film.

Therefore, research and development for implementing proper crystals and film densities by blocking harmful factors in advance during vacuum deposition have been continuously conducted.

In addition, in the case of the transparent conductive film used in the touch screen panel, since the indium tin oxide (ITO) film undergoes an etching process and a desorption process of a protective film, it must be strong in chemical treatment and excellent adhesion at each interface.

However, ITO has a change in surface resistance due to deterioration, and in itself, the adhesion to the transparent film substrate is poor, causing a problem such as dropping of the ITO pattern due to changes in the process flow over time. In order to compensate for the adhesion problem, the polymer chain is disconnected by applying a physical force to the surface of the substrate by means such as vacuum plasma or ion beam. However, this causes the surface to be damaged while activating the interface to bond well with other materials, causing a loss of reliability in the long term.

Accordingly, the present inventors have made efforts to improve the conventional problems, and thus, in a transparent conductive film including a transparent film base layer made of an organic polymer film and a transparent conductive layer made of a metal oxide, titanium is disposed between the transparent film base layer and the transparent conductive layer. The present invention was completed by improving the bonding strength between layers by forming an oxide of (Ti) series to have excellent adhesion and confirming chemical resistance even in contact with chemicals.

Korean Patent No. 1539488 Transparent Conductive Film and Method of Manufacturing the Same Republic of Korea Patent Publication No. 2015-0027845 Transparent conductive film and its manufacturing method

SUMMARY OF THE INVENTION An object of the present invention is to provide a transparent conductive film having improved bonding strength and chemical resistance and ensuring reliability.

In order to achieve the above object, the present invention is a transparent conductive film comprising a transparent conductive layer made of a metal oxide on a transparent film base layer made of an organic polymer film, between the transparent film base layer and the transparent conductive layer, titanium ( Provided is a transparent conductive film including a titanium oxide (TiO ₂ ) layer formed by depositing a Ti-based oxide. In the transparent conductive film of the present invention, at least one organic or inorganic oxide layer may be further formed on the transparent film base layer.

In the transparent conductive film of the present invention, the titanium oxide (TiO ₂ ) layer has a refractive index of 2.2 to 2.6 and is preferably deposited at a thickness of 2 to 6 nm.

In addition, when oxygen gas is added at 50 to 80% by volume with respect to the total amount of argon / oxygen gas during deposition, it is possible to provide a transparent conductive film having improved bonding strength and chemical resistance while maintaining high transparency. .

The present invention provides a transparent conductive film including a transparent film base layer made of an organic polymer film and a transparent conductive layer made of a metal oxide, wherein a titanium oxide (TiO ₂ ) layer is formed by depositing a titanium (Ti) -based oxide therebetween. Enhancement of the interlayer bonding strength and chemical resistance is achieved by making it present.

In addition, by forming the titanium oxide (TiO ₂ ) layer in an optimum condition, it can be applied to a structure including an index matching layer made of one or more organic or inorganic oxides on the transparent film base layer, it is useful as a touch screen panel film Can be applied.

1 is a schematic sectional view illustrating a transparent conductive film of the first embodiment of the invention.
2 is a schematic cross-sectional view showing a transparent conductive film of a second embodiment of the present invention,
3 is a microscopic analysis result for evaluation of the adhesive strength (Cross Cut) of the transparent conductive film prepared according to Example 1 of the present invention,
4 is a microscopic analysis result for evaluation of the adhesive strength (Cross Cut) of the transparent conductive film prepared according to Comparative Example 1 of the present invention,
5 is Chemical resistance evaluation results of the transparent conductive film prepared according to Example 1 of the present invention,
6 is a chemical resistance evaluation results of the transparent conductive film prepared according to Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in detail.

1 is a cross-sectional schematic diagram showing a transparent conductive film of a first embodiment of the present invention, wherein the present invention includes a transparent conductive layer 6 made of a metal oxide on a transparent film base layer 2 made of an organic polymer film. In the transparent conductive film, there is provided a transparent conductive film including a titanium oxide (TiO ₂ ) layer 4 formed by forming a titanium (Ti) -based oxide between the transparent film base layer and the transparent conductive layer.

In addition, in the present invention, one or more organic or inorganic oxide layers may be further formed on the transparent film base layer.

Specifically, FIG. 2 is a cross-sectional schematic diagram showing the transparent conductive film of the second embodiment of the present invention, wherein one or both surfaces of the transparent film base layer 2 made of an organic polymer film are formed to impart scratch prevention and other functions. Hard coat layer (3), titanium oxide layer (4) for securing adhesion, an antireflective layer (5) is formed thereon to secure pattern visibility when the panel is applied, a transparent conductive film formed with a transparent conductive layer (6) on the top layer Applicable to the structure, it is useful as a film for touch screen panels.

In the transparent conductive film of the present invention, the titanium oxide layer 4 is composed of an organic polymer film and a transparent film base layer 2 and a metal oxide because of the high transparency of the titanium oxide itself and the strong and stable advantages in combination with other oxides. It is possible to provide a transparent conductive film having secured reliability by not only improving the bonding strength between the layers between the transparent conductive layers 6 thus formed, but also confirming chemical resistance even in contact with chemicals.

At this time, the titanium oxide layer 4 is more preferably formed by vapor deposition (PVD), and the titanium oxide layer 4 has a refractive index of 2.2 to 2.6 and a high transparency when the thickness is 2 to 6 nm. It can maintain the bonding strength and chemical resistance between the layers while still maintaining.

EMBODIMENT OF THE INVENTION Hereinafter, the characteristic by structure for the transparent conductive film of this invention is demonstrated in detail.

The transparent film base material layer 2 has workability, flexibility, and surface smoothness, and the more excellent the strength, namely, impact resistance, required for handling, the better.

The transparent film base material is preferably polyester such as polyethylene terephthalate or polyethylene naphthalate, polyolefin, polycycloolefin, polycarbonate, polyether sulfone, polyarylate, polyimide, polyamide, polystyrene, norbornene and the like. Single component polymers or copolymerized polymers with other components can be used. Among the above examples, the polyester resin is suitable for use because of its excellent transparency, heat resistance, and mechanical properties, and most preferably, a polyester resin of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is used. .

Although it does not specifically limit as thickness of the said transparent film base material layer 2, 15-200 micrometers is preferable, More preferably, it is 30-150 micrometers, and when the said thickness is 30 micrometers or more, it is based on abrasion resistance and roll to roll. Ease of conveyance can be improved. On the other hand, when the thickness of the transparent film base layer 2 is less than 15 μm, the appearance of the film may be deteriorated by the amount of heat applied during vacuum deposition, and when the thickness of the transparent film base layer exceeds 200 μm, the thickness is transparent. It is impossible to improve the scratch resistance of the conductive layer and the RBI characteristic when the touch panel is formed.

In the transparent conductive film of the present invention, it is essential that the hard coat layer 3 contains an acrylate compound. An acrylate compound radically polymerizes by actinic light irradiation, and improves the solvent resistance and hardness of the film | membrane formed. Monofunctional or multifunctional acrylates can be polymerized alone or in combination for this purpose.

Thus, specifically, as monofunctional acrylate, methyl (meth) acrylate, n-butyl (meth) acrylate, polyester (meth) acrylate, lauryl (meth) acrylate, hydroxyethyl (meth) acryl Rate, hydroxypropyl (meth) acrylate, and the like. Moreover, since a solvent resistance etc. improve as a polyfunctional (meth) acrylate compound in which two (meth) acryloyl groups are two or more in a molecule | numerator, it is especially preferable in this invention. Specific examples of the polyfunctional (meth) acrylate include taerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, Dipentaerythritol (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimetholpropane tri (meth) acrylate, and the like. Said monomer can be used 1 type or in mixture of 2 or more types.

In the transparent conductive film of the present invention, the titanium oxide layer 4 is composed of an oxide based on titanium (Ti) metal.

Titanium oxide composed of titanium and oxygen appears in various stable phases, and the most common bonding forms are TiO, TiO ₂ , Ti ₂ O ₃ , and Ti ₃ O ₅ . All of these stoichiometry are possible, and it is common to continue to oxidize and finally reach TiO ₂ . More specifically, titanium oxides form amorphous anatase foams at low temperatures while high crystal lines and chemically form chemically resistant titanium rutile foams of titanium dioxide at high temperatures, or both.

Most titanium oxides are chemical resistant and inert to many materials. It also acts as a shield against hydrogen penetration.

As a preferable condition for providing the interlayer adhesion and chemical resistance of the titanium oxide layer 4 of the present invention, the refractive index of the titanium oxide is preferably 2.2 to 2.6, and when the refractive index is less than 2.2, transparency and adhesive strength are deteriorated. If it exceeds 2.6, the low thickness of 1 nm may adversely affect the pattern visibility of the transparent conductive film.

The thickness of the titanium oxide layer is preferably 2 to 6 nm, the thickness is less than 2 nm, the adhesive force is lowered due to the low attraction force of the polymer chain at the interface, if the thickness is more than 6 nm, the strong effect of high refractive index As a result, reflectance matching is not performed at the time of patterning the transparent conductive film, so that visibility is deteriorated.

In addition, the titanium oxide layer 4 of the present invention is formed by vapor deposition, and more preferably by PVD (physical vapor deposition) method.

At this time, it is preferable that the ratio of oxygen charged during deposition is performed at 50 to 80% by volume with respect to the total amount of argon / oxygen gas. If the ratio of the injected oxygen is less than 50% by volume, the transparency of the titanium oxide layer to satisfy the high transparency may be lowered, and when the amount of the injected oxygen exceeds 80% by volume, there may be a problem that the interfacial adhesion between the layers is lowered.

In the transparent conductive film of the present invention, the antireflection layer 5 is an optical control layer in which a low refractive index layer or a medium refractive index layer is formed alone, or a high refractive index layer and a low refractive index layer are formed of an antireflection layer having a two-layer structure. do. In this case, the anti-reflection layer performs the function of securing transmittance and index matching of the transparent conductive film by adjusting the regulation rate and the layer thickness for each wavelength.

The low refractive index layer of the antireflection layer includes a binder component, a fluorine additive, and may be used by adding inorganic particles.

Specifically, as the binder component constituting the low refractive index layer, an acrylate resin is preferable, and as a preferable monomer for the acrylate resin, methyl (meth) acrylate, n-butyl (meth) acrylate, polyester ( Monofunctional acrylates such as meth) acrylate, lauryl (meth) acrylate, hydroxyethyl (meth) acrylate, and hydroxypropyl (meth) acrylate; Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipenta Polyfunctional acrylates, such as pentaerythritol hexa (meth) acrylate and a trimethylol propane tri (meth) acrylate, etc. are mentioned. More preferably, it is polyfunctional acrylate and the monomer for the said acrylate resin is used 1 type or in mixture of 2 or more types.

As the binder component constituting the high refractive index layer, a (meth) acrylate compound is used. At this time, the (meth) acrylate compound is preferable because it is radically polymerized by actinic radiation and improves the solvent property and hardness of the film to be formed. Moreover, the (meth) acryloyl group is a polyfunctional (meth) having two or more in the molecule. The acrylate compound is particularly preferred because of improved solvent resistance and the like. For example, pentaerythritol tri (meth) acrylate, trimetholpropane tri (meth) acrylate, glycerol tri (meth) acrylate, ethylene modified trimetholpropane tri (meth) acrylate, tris- (2 Trifunctional (meth) acrylates, such as -hydroxyethyl)-isocyanuric acid ester tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythrol hexa (Meth) acrylates more than tetrafunctional, such as (meth) acrylate, are mentioned.

In order to improve the dispersibility of particle | grains, the binder component which comprises a high refractive index layer can use the (meth) acrylate compound which has acidic functional groups, such as a carboxyl group, a phosphoric acid group, and a sulfonic acid group. Specifically, as an acidic functional group containing monomer, unsaturated carboxylic acid, such as acrylic acid, methacrylic acid, a crotonic acid, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl phthalic acid, diphenyl-2- Phosphoric acid (meth) acrylic acid ester, such as (meth) acryloyloxyethyl phosphate, 2-sulfoester (meth) acrylate, etc. are mentioned. In addition, the (meth) acrylate compound which has a bond with polarity, such as an amide bond, a urethane bond, an ether bond, can be used.

In the transparent conductive film of the present invention, the constituent material of the transparent conductive layer 6 is not particularly limited, and is In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu. Metal oxides of at least one metal selected from the group consisting of are suitably used. The said metal oxide may contain the metal atom shown to the said group further as needed. Among various composite oxides, indium-tin composite oxide (ITO) is particularly preferably used.

The transparent conductive layer 6 is formed of an amorphous or crystalline structure. Usually, it is preferable that it is crystalline, and when it is amorphous, you may convert into crystalline by crystal telephone processing. Although it does not specifically limit as a crystallization processing method, You may employ | adopt a heat processing method. The heat treatment temperature and time may be sufficient as long as the transparent conductive layer can be crystallized reliably. In the case of ITO, the conditions necessary for crystallization differ according to the ratio of indium and tin, From a productivity viewpoint, 140 degreeC 1 hour or less is preferable, and 140 degreeC 30 minutes or less are more preferable.

When ITO is used as the material of the transparent conductive layer 6, the tin oxide (SnO ₂ ) content in the metal oxide is 0.5 to about the total amount of tin oxide (SnO ₂ ) and indium oxide (In ₂ O ₃ ). It is preferable that it is 15 weight%, and it is more preferable that it is 3 to 10 weight%. At this time, when the amount of the tin oxide is too large, crystallization of the ITO film is difficult, and the transparency and the stability of the resistance value may not be sufficient.

In addition, the refractive index of the transparent conductive layer 6 is preferably 1.5 to 2.5, more preferably 1.87 to 2.3, most preferably 1.9 to 2.2.

Hereinafter, the present invention will be described in more detail with reference to Examples.

This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

<Example 1>

After mounting a 125 μm PET film (manufactured by Toray) on the unwinder of the sputter, MF power was applied while Ar: O ₂ gas was supplied in a volume ratio of 25:75 in a chamber equipped with a Ti target. Titanium oxide (TiO ₂ ) having a refractive index of 2.3 was deposited to a thickness of 2 nm on the film substrate by the formation of plasma and the collision of particles and ions. Then, 23 nm of indium tin oxide (ITO) was deposited as a transparent conductive film by application of DC voltage, and the transparent conductive film was produced.

<Example 2>

After mounting a 125 μm PET film (manufactured by Toray) hard-coated on the unwinder of the sputter, Ar: O ₂ gas was supplied in a volume ratio of 25:75 in a chamber equipped with a Ti target, and MF power was applied thereto. Titanium oxide (TiO ₂ ) having a refractive index of 2.3 was deposited to a thickness of 3 nm on the film substrate due to plasma formation and collision of particles and ions. Thereafter, Ar, O ₂ gas was supplied to the chamber of the high refractive index niobium (Nb) target, and MF power was applied to deposit an Nb ₂ O ₅ layer having a thickness of about 7 nm. The refractive index of the Nb ₂ O ₅ layer was about 2.35. Subsequently, Ar, O ₂ gas was supplied to the chamber of the low refractive index silicon (Si) target, and MF power was applied to deposit a SiO _x layer having a thickness of about 65 nm. The refractive index of the SiO _x layer is 1.46 to 1.48. Thereafter, 23 nm of ITO was deposited by applying a DC voltage as a transparent conductive film to prepare a transparent conductive film.

Comparative Example 1

Under the same conditions as in Example 1, a transparent conductive film in which no titanium oxide (TiO ₂ ) layer was formed was formed between the transparent film base layer and the transparent conductive layer.

Comparative Example 2

Under the same conditions as in Example 2, a transparent conductive film in which no titanium oxide (TiO ₂ ) layer was formed was formed between the transparent film base layer and the transparent conductive layer.

Comparative Example 3

Under the same conditions as in Example 2, the thickness of the titanium oxide (TiO ₂ ) layer was deposited at a level of 1 nm.

<Comparative Example 4>

Under the same conditions as in Example 2, the thickness of the titanium oxide (TiO ₂ ) layer was deposited to a level of 7 nm.

Comparative Example 5

A titanium oxide (TiO ₂ ) layer having a refractive index of 2.7 was deposited under the same conditions as in Example 2.

Experimental Example 1 Evaluation of Adhesion (Cross-Cut)

The transparent conductive films prepared in Examples 1 to 2 and Comparative Examples 1 to 5 were stored at a constant temperature and humidity temperature of 85 ° C. and a humidity of 85% for 120 hours. After that, using a knife to make a net-shaped scratches, sticking a tape of Nitto Denko, peeled off and observed under a microscope.

Experimental Example 2 Evaluation of Chemical Resistance (NaOH Rubbing)

The transparent conductive films prepared in Examples 1 to 2 and Comparative Examples 1 to 5 were heat-treated at 140 ° C. for 60 minutes in a box oven to crystallize the ITO layer. Thereafter, the process chemicals (NaOH, etc.) were buried in a fort (cloth), and the film was gently rubbed for 60 seconds to 1 minute, and then the appearance was observed under a microscope.

As confirmed in Table 1, excellent from the cut cut and the chemical resistance evaluation (NaOH Rubbing) for the transparent conductive films of Examples 1 and 2 in which titanium oxide (TiO ₂ ) was deposited when the transparent conductive film was manufactured. Adhesion and chemical resistance were confirmed.

In particular, the apparent difference in peeling degree from the cross cut results of the transparent conductive films prepared in Example 1 and Comparative Example 1 in FIGS. 3 and 4 was confirmed from the results of microscopic analysis.

In addition, with respect to the results of chemical resistance evaluation (NaOH Rubbing) for the transparent conductive films prepared in Example 1 and Comparative Example 1, the transparent conductive prepared in Example 1, the titanium oxide (TiO ₂ ) shown in FIG. In the case of the film, the appearance of the film was maintained without change, while the film of Comparative Example 1 prepared without titanium oxide (TiO ₂ ) as shown in FIG. 6 was observed to have a phenomenon in which the deposited layer was peeled off. Therefore, in the case of the film prepared according to Example 1, the chemical resistance strong to the process chemicals was visually confirmed.

Based on the interlayer adhesion and chemical resistance according to the presence of the titanium oxide (TiO ₂ ) layer on the transparent conductive film, in the case of Comparative Examples 3 and 4 where the thickness of the titanium oxide (TiO ₂ ) layer deviated, the titanium oxide (TiO ₂ ) deposited layer Even if it is included, physical properties such as adhesive strength, chemical resistance, etc. were not satisfied at the same time.

In addition, in the case of Comparative Example 5, which is outside the refractive index range of the titanium oxide (TiO ₂ ) deposited layer, the physical properties such as adhesion, chemical resistance, and pattern visibility were not satisfied, so that the thickness and refractive index of the titanium oxide (TiO ₂ ) layer were Depending on the optimization, the desired property change can be realized.

In view of the above, by providing a transparent conductive film having not only improved bonding strength between layers while maintaining the transparency of the present invention, but also a reliable transparent conductive film having chemical resistance in contact with chemicals, it can be used in various industrial products. It is useful for the film for panels.

Although the present invention has been described in detail only with respect to the embodiments described above, it will be apparent to those skilled in the art that various changes and modifications can be made within the spirit of the present invention, and such modifications and modifications belong to the appended claims. will be.

1: transparent conductive film
2: transparent film base material layer
3: hard coat layer
4: titanium oxide layer
5: antireflection layer
6: transparent conductive layer

Claims (4)

In a transparent conductive film comprising a transparent conductive layer made of a metal oxide on a transparent film base layer made of an organic polymer film,
A transparent conductive film comprising a titanium oxide (TiO ₂ ) layer formed by forming a titanium (Ti) -based oxide between the transparent film base layer and the transparent conductive layer. The transparent conductive film of claim 1, wherein at least one organic or inorganic oxide layer is further formed on the transparent film base layer. The transparent conductive film of claim 1, wherein the titanium oxide (TiO ₂ ) layer has a refractive index of 2.2 to 2.6 and a thickness of 2 to 6 nm. The transparent conductive film according to claim 1, wherein the titanium oxide (TiO ₂ ) layer is formed by adding 50 to 80% by volume of oxygen gas with respect to the total amount of argon / oxygen gas during deposition.

Images