JP2000056321A - Production of transparent electroconductive laminate for liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the transparent electroconductive laminate for the liquid crystal display, which is excellent in alkali resistance. SOLUTION: The method for producing the laminate is comprised of providing a cured resin layers on the both surfaces of a polymer film, then providing a metal oxide layer on at least one surface of the cured resin layer and forming a transparent electroconductive thin film on the metal oxide layer by sputtering method while introducing water in order to adjust the water partial pressure in the film forming atmosphere to 2.0×10-5-3.0×10-6 Torr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a transparent conductive laminate for a liquid crystal display, and more particularly, to a polymer film in which a cured resin layer is provided on both sides and a metal oxide layer is provided on at least one side of the cured resin layer. The present invention relates to a method for producing a conductive laminate for liquid crystal, in which a transparent conductive thin film mainly composed of indium oxide is formed under specific conditions on a metal oxide layer of a provided polymer laminated film.

[0002]

2. Description of the Related Art In recent years, portable and portable information devices such as pagers, mobile phones, electronic organizers, and personal digital assistants have begun to spread. In order to improve the portability of these information devices, further reduction in thickness, weight, and breakage resistance are required. Conventionally, a heavy, thick, and fragile glass substrate has been used as a transparent electrode substrate for LCDs and touch panels, but a transparent resin substrate has been proposed as an alternative material. However, the transparent resin substrate is inferior to the glass substrate in basic characteristics such as durability, solvent resistance, and gas barrier properties. For example, when a transparent resin substrate is used as an electrode substrate for LCD, a gas barrier property can be imparted by providing a metal oxide layer. Also, in the process of forming the liquid crystal alignment film, when coating a coating solution in which a precursor material of the liquid crystal alignment film is dissolved in a solvent such as N-methylpyrrolidone,
There was a problem that the transparent resin substrate was damaged by whitening, swelling, and the like due to the solvent. To solve such a problem,
The present inventors have provided a cured resin layer on both surfaces of a polymer film, and provided a metal oxide layer on at least one surface of the polymer laminated film. A conductive thin film was formed, and a transparent conductive laminate for liquid crystal display was fabricated and studied.

A transparent conductive thin film is generally made of ITO (In-Sn-O)
Films are widely used as electrode materials for liquid crystal displays, touch panels, etc., taking advantage of their high conductivity and high transparency characteristics. In recent years, a DC magnetron sputtering method has been generally used as a method for forming the ITO film from the viewpoints of controllability of a film forming rate, uniformity of a formed thin film, and the like. In particular, recent advances in thin film formation technology have been remarkable, and it has become possible to form a transparent conductive thin film on a polymer film substrate having little heat resistance. Above all, the sputtering method is one of the most utilized techniques because it has features such as being capable of forming a film for a long time, maintaining the composition even after the film is formed for a long time, and being easy to widen.

[0004] The present inventors formed an ITO film on the above-mentioned polymer laminated film by using this sputtering method and evaluated its practicality. In the process of manufacturing a liquid crystal display element, adhesiveness, heat resistance, and chemical resistance are generally required as necessary properties of a transparent conductive laminate for liquid crystal display. However, DC using ITM (In-SnMetal) or ITO target
When a film was formed on the metal oxide of the polymer laminated film by the magnetron sputtering method, the alkali resistance of the ITO thin film was sometimes poor depending on the film forming conditions.

[0005]

The object of the present invention is to provide an ITM
(In-SnMetal) or an ITO target using a magnetron sputtering method to provide a transparent conductive laminate for liquid crystal displays with good alkali resistance when continuously deposited on the metal oxide layer of a polymer laminate film. To provide.

[0006]

According to the present invention, there is provided a polymer having a cured resin layer provided on both surfaces of a polymer film, and a metal oxide layer provided on at least one surface of the cured resin layer. In the method for producing a transparent conductive laminate for a liquid crystal display in which a transparent conductive thin film is formed on the metal oxide layer of a laminated film by a sputtering method, the partial pressure of water present in a film formation atmosphere is 2.0 × 10 ⁻⁵ Torr. From 3 × 10 ^-6 T
A method for producing a transparent conductive laminate having good alkali resistance and suitable as a substrate for a liquid crystal display, comprising forming a transparent conductive thin film while introducing water so as to fall within the range of orr.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The method for forming the transparent conductive thin film in the present invention uses a sputtering method. In a sputtering method for forming a layer mainly containing indium oxide, an alloy mainly containing indium or a sintered body mainly containing indium oxide can be used as a target. In the former, an inert gas such as argon and a reactive gas such as oxygen gas are introduced into a vacuum chamber to perform reactive sputtering. In the latter case, sputtering is performed using an inert gas such as argon alone or a mixture of an inert gas such as argon and a reactive gas such as a slight amount of oxygen gas. Known methods such as direct current or high frequency bipolar sputtering, direct current or high frequency magnetron sputtering, and ion beam sputtering can be applied to the sputtering method. Among them, the magnetron method is preferable because the plasma impact on the substrate is small and high-speed film formation is possible.

Further, the present invention can be applied to both a batch type and a roll-to-roll type as a sputtering apparatus. Considering the productivity, the roll-to-roll system is particularly preferable.

The present inventors have repeatedly studied a transparent conductive laminate for a liquid crystal display in which an ITO thin film is formed on a metal oxide layer of a polymer laminated film described above. In particular, it was difficult to satisfy the alkali resistance.
The present inventors have made intensive studies, and the alkali resistance of the transparent conductive laminate for liquid crystal display is determined by the water pressure in the film formation atmosphere when forming the ITO thin film on the metal oxide layer of the polymer laminated film. I figured out. This water was mainly released from the polymer film and the cured resin layer.
In order to continuously produce a transparent conductive laminate for liquid crystal display formed by transporting a polymer laminated film and forming a transparent conductive thin film mainly composed of indium oxide, an inert gas which is a conventionally used gas is used. In addition to (mainly argon) and oxygen, the water content in the film formation atmosphere was monitored by a quadrupole mass spectrometer, and the water pressure was 2.0x10 ^{-5 to} 3.0x10 ^-6 To
Sputtering while adding moisture from outside the system to keep it constant within the range of rr, no cracking or peeling is seen in the ITO thin film after alkali test, and a transparent conductive laminate for liquid crystal display with good alkali resistance. I found that I could get my body. The moisture (massnumber1
When 8) was less than 3.0 × 10 ⁻⁶ Torr, cracks were observed in the ITO thin film after the alkali test so as to be visually confirmed, and the alkali resistance of the transparent conductive laminate for liquid crystal display was poor. Moisture in the film formation atmosphere (massnumber18)
Exceeds 2 × 10 ^-5 Torr, cracks are visible in the ITO thin film after the alkali test and some of the peeled-off parts are seen, and the alkali resistance of the transparent conductive laminate for liquid crystal display is poor. It became bad. The moisture (massnumber18) existing in the film formation atmosphere changes from 3.0x10 ^-6 Torr to 2x10 ^-5 To
In the case of the range of rr, no crack or peeling was observed in the ITO thin film after the alkali test, and the alkali resistance of the transparent conductive laminate for liquid crystal display was good. As described above, it was found that the water pressure existing during the film formation had a great effect on the alkali resistance of the transparent conductive laminate for liquid crystal display. When a suitable amount of water is added to the film formation atmosphere and the amount of water is within the above range, ITO is formed on a metal oxide layer such as SiOx, and such introduction of water reduces stress at the interface between ITO and SiOx. It is thought that as a result, the adhesion of ITO on SiOx is improved and the alkali resistance is improved. If the partial pressure is lower than the above range, the film stress of the ITO thin film itself becomes very high, so that the adhesiveness at the interface with SiOx is deteriorated, and it is considered that cracks occur. If the partial pressure is higher than the above range, the ITO thin film itself has a film quality weak to alkali, and it is considered that cracks occur in the ITO thin film and peeling occurs.

[0010] The transparent conductive thin film used in the present invention mainly contains indium oxide. Indium oxide is a transparent electrical insulator by nature, but becomes a semiconductor when (1) it contains a small amount of impurities or (2) it is slightly lacking oxygen. Preferred semiconductor metal oxides include, for example, indium oxide containing tin or fluorine as impurities. Particularly preferred is a thin film of indium oxide containing 2 to 20% by weight of tin oxide. The thickness of the transparent conductive thin film mainly containing indium oxide used in the present invention is preferably 100 ° or more in order to obtain sufficient conductivity. The upper limit is not particularly limited, but is about 3000 °.

As the polymer film in the present invention,
Although it is not particularly limited as long as it is a transparent organic polymer compound having heat resistance, the heat resistance is usually 100 ° C. or higher, preferably 130 ° C. or higher, such as polyether sulfone, polycarbonate, polysulfone, polyarylate, and polyester. , Polyamide, polyimide, polyolefin and the like. Of course, they can be used as homopolymers, copolymers, alone or as blends.

Such a polymer film includes a film-like film. The thickness of such a polymer film is usually 10
１０００1000 μm.

In the present invention, the metal oxide layer is selected from the group consisting of silicon, aluminum, magnesium and the like.
A metal oxide mainly composed of one or more kinds of metals is mentioned, and is known as a material having excellent gas barrier properties. These oxide layers are formed by a sputtering method, an ion plating method, a plasma CVD method, or the like.

Among them, a metal oxide containing silicon oxide having a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0 as a main component is preferable in terms of gas barrier properties, transparency, surface smoothness, flexibility and the like. It is. The ratio of the number of oxygen atoms to silicon oxide is analyzed and determined by X-ray electron spectroscopy, X-ray microspectroscopy, Auger electron spectroscopy, Rutherford backscattering, or the like. If this ratio is smaller than 1.5, the transparency becomes poor, so that 1.5 to 2.0 is preferable.

The metal oxide layer has a thickness of 5 nm to 200 nm.
The range of nm is preferred. If the thickness is less than 5 nm, it is difficult to form a uniform film, and a portion where the film is not formed occurs, and gas penetrates from this portion, resulting in poor gas barrier properties. On the other hand, if the thickness is more than 200 nm, not only the transparency is lost but also the flexibility is poor, cracks are generated and the gas barrier property is impaired.

For higher transparency requirements, the above silicon oxide SiOx (x is 1 to 2) containing magnesium fluoride in an amount of 5 to 30% by weight based on the total weight is preferred.

The cured resin layer of the present invention has good adhesion to a polymer film and a metal oxide layer, and has high chemical resistance,
Those having bending resistance are good. In order to reduce the curl deformation of the polymer laminated film used in the present invention, it is preferable that the same resin layer is applied to both surfaces of the polymer film with substantially the same thickness.

Specific examples of such a cured resin layer include a thermosetting resin such as an epoxy resin, an acrylic resin, an acrylic epoxy resin, a melamine resin, a phenol resin or a urethane resin. Examples of the photopolymerizable polymer include polyester acrylate, polyester urethane acrylate, and polyol acrylate. These may be used as a mixture of two or more.

The layer structure of the polymer laminated film in the present invention may be, for example, cured resin layer / polymer film / cured resin layer / metal oxide layer / ITO layer. An anchor coat layer can be interposed between the cured resin layer and the polymer film or between the cured resin layer and the metal oxide layer in order to increase the adhesion and the like.

[0020]

The present invention will now be described more specifically with reference to examples.

(1) Quadrupole mass spectrometer The quadrupole mass spectrometer used in the present invention is an apparatus for mainly evaluating the types of elements present in the vacuum chamber and the amounts of the elements. In the present invention, this quadrupole mass spectrometer is particularly used as a partial pressure gauge. The equipment used this time is a MicropoleAnalyzer ultra-compact partial pressure gauge system MPA manufactured by MC Electronics. This time, the model number MPA-CF-215, which has a maximum operating pressure of 5 mTorr and an analytical mass range of 2 to 100 AMU, was used as the MPA sensor.

(2) Evaluation of Alkali Resistance Alkali resistance was determined by placing a sample at 30 ° C. in a 3.5 wt% NaOH aqueous solution.
Dipped for 10 minutes, and then dried after thoroughly washing with running water, and visually observing the appearance,
When no change was observed, it was evaluated as having alkali resistance.

(3) ITO Film Forming Method FIG. 1 is a configuration diagram of an apparatus for performing the film forming method of the present invention. A roll of various polymer laminated films is set on the unwinding shaft 4 as a substrate film, and the film is unwound and set so that it can be wound on the winding core set on the winding shaft 7 along the illustrated film forming path. I do.

Example 1 As a polymer film, a polycarbonate film having a thickness of 100 μm and a Tg measured by DSC of 150 ° C. was used. A radiation-curable resin layer having a thickness of 5 μm was provided on both surfaces of the polycarbonate film. As the radiation-curable resin layer, roll a solution prepared by mixing Alonix M400 and M8030 manufactured by Toa Gosei Chemical Co., Ltd. in a ratio of 1: 1, 7 phr of Igarcure 184 manufactured by Ciba Geigy as a photo-curing agent, and 0.1 phr of SH28PA as a leveling agent. Coating was performed using a bar RDS10, and ultraviolet curing was performed using a high-pressure mercury lamp of 160 W / cm at an integrated light amount of about 700 mJ / cm ² . The polymer film obtained by laminating the cured resin layers thus obtained was set in a take-up type magnetron sputtering apparatus and evacuated to 2 × 10 ⁻⁵ Torr. Thereafter, an O ₂ / Ar mixed gas (O ₂ / Ar = 30%) was introduced into the tank at 100 sccm, and the pressure was increased to 2.0 ×
After maintaining at 10 ^-3 mTorr, the target was a Si (B-doped) target, the main roll temperature was set to room temperature, the film speed was set to Vf = 1.0 m / min, and the input power density was set to 1 W / cm ² A polymer laminated film in which a metal oxide layer made of silicon oxide was formed on the cured resin layer by continuous film formation was obtained.

After that, the Si target was replaced with an ITO target and exhausted. The ultimate vacuum before film formation was 3 × 10 ⁻⁶ Torr. Then, an O ₂ / Ar mixed gas (O ² /Ar=1.2%)
After introducing 50 sccm and maintaining the pressure at 3.0 × 10 ⁻³ Torr, the temperature of the main roll was set to room temperature, the film speed was set to Vf = 0.1 m / min, and the input power density was set to 1 W / cm ² . The water (mass number 18) present in the film formation atmosphere at that time is observed with a quadrupole mass spectrometer (MPA), and the silicon oxide is formed while introducing water so that the water pressure becomes 9 × 10 ⁻⁶ Torr. A transparent conductive laminate was obtained by continuously forming an ITO layer on the metal oxide layer. Table 1 shows the evaluation results of the obtained transparent conductive laminate.
Shown in It was a transparent conductive laminate having excellent alkali resistance.

Example 2 The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was set in a take-up type magnetron sputtering apparatus and set to 3 × 10
Evacuated to -6 Torr. Then, an O ₂ / Ar mixed gas (O ₂ / Ar =
1.2%) into the tank, keep the pressure at 3.0x10 ^-3 Torr, then set the main roll temperature to room temperature and the film speed
Vf was set to 0.1 m / min and the input power density was set to 1 W / cm ² to form a continuous film. The moisture (massnu) existing in the film formation atmosphere at that time
mber18) with a partial pressure of 1.2 using a quadrupole mass spectrometer (MPA).
A transparent conductive laminate was obtained by continuously forming a film while introducing moisture so as to be at x10 ^-5 Torr. Table 1 shows the evaluation results of the obtained transparent conductive laminate. It was a transparent conductive laminate having excellent alkali resistance.

Example 3 The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was set in a take-up type magnetron sputtering apparatus and set to 3 × 10
Pumped down to ^-6 Torr. Then, an O ₂ / Ar mixed gas (O ₂ / Ar =
1.2%) was introduced into the tank at 150 sccm, the pressure was maintained at 3.0x10-3 Torr, the main roll temperature was set to room temperature, and the film speed was set to
Vf was set to 0.1 m / min and the input power density was set to 1 W / cm ² to form a continuous film. The moisture (massnu) existing in the film formation atmosphere at that time
mber18) with a quadrupole mass spectrometer (MPA) with a partial pressure of 2.0
A transparent conductive laminate was obtained by continuously forming a film while introducing moisture so as to be at x10 ^-5 Torr. Table 1 shows the evaluation results of the obtained transparent conductive laminate. It was a transparent conductive laminate having excellent alkali resistance.

Comparative Example 1 The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was set in a take-up type magnetron sputtering apparatus and set to 3 × 10
Pumped down to ^-6 Torr. Then, an O ₂ / Ar mixed gas (O ₂ / Ar =
1.2%) into the tank, keep the pressure at 3.0x10 ^-3 Torr, then set the main roll temperature to room temperature and the film speed
Vf was set to 0.1 m / min and the input power density was set to 1 W / cm ² to form a continuous film. The moisture (massnu) existing in the film formation atmosphere at that time
mber18) has a partial pressure of 2.9 with a quadrupole mass spectrometer (MPA).
A layered product was obtained by continuously forming a film while introducing water so as to be at x10 ^-5 Torr. Table 1 also shows the evaluation results of the obtained laminate. Cracks were observed in the ITO thin film after the alkali test so as to be visually confirmed, and some of the peeled portions were observed, and the alkali resistance was poor.

Comparative Example 2 The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was placed in a take-up type magnetron sputtering apparatus and set to 1 × 10
Pumped down to ^-6 Torr. Then, an O ₂ / Ar mixed gas (O ₂ / Ar =
1.2%) into the tank, keep the pressure at 3.0x10 ^-3 Torr, then set the main roll temperature to room temperature and the film speed
Vf was set to 0.1 m / min and the input power density was set to 1 W / cm ² to form a continuous film. The moisture (massnu) existing in the film formation atmosphere at that time
mber18) quadrupole mass spectrometer (MPA) partial pressure 2x1
A transparent conductive laminate was obtained by continuously forming a film while introducing water so that the pressure became 0 ^-6 Torr. Table 1 also shows the evaluation results of the obtained laminate. Cracks were observed in the ITO thin film after the alkali test so as to be visually confirmed, and the alkali resistance was poor.

Comparative Example 3 The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was placed in a take-up type magnetron sputtering apparatus and set to 1 × 10
Pumped down to ^-6 Torr. Then, an O ₂ / Ar mixed gas (O ₂ / Ar =
1.2%) into the tank, keep the pressure at 3.0x10 ^-3 Torr, then set the main roll temperature to room temperature and the film speed
Vf was set to 0.1 m / min and the input power density was set to 1 W / cm ² to form a continuous film. The moisture (massnu) existing in the film formation atmosphere at that time
mber18) 1x1 by quadrupole mass spectrometer (MPA)
A layered product was obtained by continuously forming a film while introducing water so as to obtain 0 ^-6 Torr. Table 1 also shows the evaluation results of the obtained laminate. Cracks were observed in the ITO thin film after the alkali test so as to be visually confirmed, and the alkali resistance was poor.

[0031]

[Table 1]

[0032]

According to the present invention, a cured resin layer is provided on both sides of a polymer film by a sputtering method regardless of a batch method or a roll-to-roll method, and the cured resin layer is formed on at least one surface of the cured resin layer. In forming a transparent conductive thin film by a sputtering method on the metal oxide layer of the polymer laminated film provided with a metal oxide layer,
Moisture present in the deposition atmosphere is always 2.0x10 ^-5 Torr to 7x
A transparent conductive laminate for liquid crystal display having good alkali resistance was obtained by forming a film while introducing moisture so as to have a pressure of 10 ^-6 Torr.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for performing a film forming method of the present invention.

[Explanation of symbols]

 1. Vacuum chamber 2. Long roll polymer film 3. Target 4. Unwinding shaft 5. Main roll 6. Sub-roll 7. Winding shaft

Claims (3)

[Claims] 1. A polymer laminated film in which a cured resin layer is provided on both surfaces of a polymer film, and a metal oxide layer is provided on at least one surface of the cured resin layer. In the method for manufacturing a transparent conductive laminate for a liquid crystal display having a transparent conductive thin film formed thereon by a sputtering method, the partial pressure of water in a film formation atmosphere is 2.0 × 10 ⁻⁵ Torr.
A method for producing a transparent conductive laminate for liquid crystal display having good alkali resistance, wherein a transparent conductive thin film is formed while introducing water so as to fall within a range of from 3 to 10 ^-6 Torr. 2. The transparent liquid crystal display according to claim 1, wherein the transparent conductive thin film contains indium oxide as a main component and at least one oxide selected from tin, zinc and gallium. A method for manufacturing a conductive laminate. 3. The metal oxide layer has a thickness of 5 to 200 nm.
3. The transparent conductive laminate for a liquid crystal display according to claim 1, wherein a silicon oxide having a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0 is a main component. 4. Manufacturing method.