JPH0389412A - Transparent conductive film - Google Patents

Abstract

PURPOSE:To improve the wettability of various laminates on the surfaces of a transparent thin film and a transparent base by laminating the transparent thin film and a hydrophilic-processed transparent layer in this order on one of the faces of the transparent film base, and forming the same king of hydrophilic layer on the other face. CONSTITUTION:On one of the faces of a transparent film base 1, a transparent conductive thin film 2 and a hydraulically-processed transparent layer 3 are laminated in order, while on the other face a layer 4 which is similarly hydraulically processed is formed. The thickness of the film 2 is made 50Angstrom or more. The level of wettability of these hydrophilic layers is made so that the contact angle of water on both faces of film is 20 degrees or less. As the layer 4 is used a thin film of silicon oxide comprising SiO, SiO2, and their intermediate oxides, wherein the thickness is made 20Angstrom or more.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a transparent conductive film having a hydrophilic treatment layer.

[Conventional technology]

In general, thin films that are transparent in the visible light range and have conductivity are used as transparent electrodes in new display systems such as liquid crystal displays (LCDs), electroluminescent displays (ELDs), and electrochromic displays (ECDs). It is used in applications such as antistatic and electromagnetic wave shielding for transparent articles, touch panels, transparent tablets, and planar heating elements.

Conventionally, so-called conductive glass, in which an indium oxide thin film is formed on glass, is well known as such a transparent conductive thin film, but because the base material is glass, it has poor flexibility and processability. , which may be undesirable depending on the application.

For this reason, in recent years, transparent conductive films based on various synthetic resin films, including polyethylene terephthalate film, have been developed due to their flexibility, processability, excellent impact resistance, and light weight. Thin films have been praised.

[Problem to be solved by the invention]

However, conventional transparent conductive thin films using such film base materials have poor scratch resistance on the thin film surface and the base material surface, and the thin film surface is scratched during use, resulting in increased electrical resistance. There is a risk of wire breakage, and there are also problems such as scratches on the surface of the substrate during use, reducing the transparency of the entire film.

In addition, because the film base material has poor heat resistance, low molecular weight substances in the film base material ooze out onto the surface of the base material when used at high temperatures, resulting in problems such as poor transparency of the film as a whole. However, the wettability of various laminates provided on the surface of the thin film and the surface of the base material is poor, and the adhesion thereof cannot be obtained sufficiently, leading to the following problems.

For example, when forming a display layer (light-emitting layer) in various display systems such as LCD, EL, and ECD on a conductive thin film, the adhesion of each display layer to the conductive thin film is poor, resulting in cissing and peeling. However, there were problems such as uneven display and uneven light emission during operation.

In addition, for applications such as touch panels, transparent tablets, and sheet heating elements, a resist is applied to the conductive thin film to form a pattern, but the wettability of this resist is poor, causing repellency and peeling. However, there were problems such as pattern breakage and deterioration of pattern accuracy.

Furthermore, in the various applications mentioned above, conductive pastes such as Cu and Ag are used to take out the electrodes, but this paste has poor wettability to the conductive thin film, causing repellency and peeling, making it difficult to use as an electrode. There was also the problem of poor reliability.

In addition, unlike such lamination formation on the surface of a conductive thin film, letters and
It is common practice to laminate printing layers such as symbols and patterns, coating layers for cosmetics, etc., but even in this case, the wettability of these laminates to the base material surface is poor, causing problems such as repelling and peeling. was there.

In view of the above-mentioned conventional problems, this invention has excellent wettability to the base of various laminates provided on the surface of a conductive thin film and the surface of a film base material, and has good scratch resistance on both surfaces. It is also an object of the present invention to provide a transparent conductive film that also has the high transparency and heat resistance desired for this type of film.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the inventors formed a specific treatment layer on the conductive thin film provided on one side of the film base material, and By forming the same specific treatment layer on the surface as above, the wettability of various laminates such as various display layers, resists, Ag pastes, printing layers, etc. provided on the surface of the thin film and film base material can be greatly improved. The present invention was completed based on the knowledge that good results could be obtained in terms of the scratch resistance of the thin film surface and the film base material surface, and the transparency and heat resistance of the entire film.

That is, the present invention provides a transparent film base material, in which a transparent conductive thin film and a transparent hydrophilic treatment layer are laminated in this order on one side, and a hydrophilic treatment layer similar to the above is formed on the other side. The present invention relates to a transparent conductive film characterized by:

[Structure and operation of the invention]

As the film base material used in this invention, various transparent synthetic resin films can be used, and specifically, polyethylene terephthalate, polyimide, polyether sulfone, polyether ether ketone, polycarbonate, polypropylene, polyamide, polyester, etc. Examples include acrylic and cellulose propionate. Although the thickness of these film base materials is not particularly limited, it is usually good to be about 2 to 300 μm.

The surface of this film base material has been subjected to etching treatments such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, etc., and undercoating treatments beforehand, and a conductive thin film and a hydrophilic treatment layer are provided on the surface. The adhesion to the above-mentioned base material may be improved. Further, before providing the above-mentioned thin film or treated layer, dust removal and cleaning may be performed by solvent cleaning, ultrasonic cleaning, etc. as necessary.

In this invention, a transparent conductive thin film is formed on one side of such a film base material. The formation of this thin film is
This can be done by employing conventionally known techniques such as vacuum evaporation, sputtering, and ion blating.

Further, the thin film material is not limited, for example, indium oxide containing tin oxide, tin oxide containing antimony,
Further, metals or alloys such as Ag5Au, Cu, Nix Tis Pd, etc. are used.

The thickness of the conductive thin film is preferably 50 Å or more,
If it is thinner than this, it is difficult to form a continuous film showing good conductivity with a surface resistance of 10 9 Ω/hole or less. On the other hand, if the thickness is too thick, the transparency will be reduced, so a particularly suitable thickness is about 100 to 4,000.

In this invention, after forming a transparent conductive thin film as described above, a transparent hydrophilic treatment layer is formed on this thin film, and the other side of this film base material is also formed in the same manner as described above. It is characterized by forming a hydrophilic treated layer. This type of hydrophilic treatment layer greatly improves the wettability of various laminates such as the various display layers, resists, and printing layers described above, and also improves the scratch resistance of the conductive thin film surface and the film base material surface. is improved, and good results can also be obtained in terms of the heat resistance and transparency of the entire film.

Here, the degree of wettability brought about by the above-mentioned treatment layer is such that, while the contact angle [θ] of water on both sides of the film is usually 80 degrees or more before this treatment layer is provided, the contact angle [θ] of water on both sides of the film is at most 50 degrees. Thereafter, the contact angle is usually reduced to 20 degrees or less, particularly preferably 10 degrees or less. Note that this contact angle [θ] is, for example, CNTACT-
It can be measured using ANGLE METER (format CA-DT).

Particularly suitable as this hydrophilic treatment layer is S
Examples include a silicon oxide thin film made of iO% S i Ot and silicon oxide in an intermediate oxidation state.

The thickness of this thin film is preferably 20 Å or more, usually 50 to 3,000, particularly preferably 100 to 2,000.
It is best to set the number to 0. If it is too thin, it will be difficult to form a continuous film, and you will not be able to expect much improvement in wettability, scratch resistance, heat resistance, or transparency.On the other hand, if it is too thick, conductivity and transparency may deteriorate, or cracks may occur. ,
Neither is preferable.

Formal methods for forming such a hydrophilic treatment layer include, for example, vacuum evaporation, sputtering, ion blating, coating, etc., and an appropriate method is adopted depending on the type of material used and the required film thickness. can do.

FIG. 1 shows an example of the transparent conductive film of the present invention. In the figure, 1 is a transparent film base material, and 2 is a transparent conductive film formed on one side of this film base material 1. thin film,
Reference numeral 3 designates a transparent hydrophilic treatment layer laminated on this thin film 2, and 4 designates a hydrophilic treatment layer similar to the above formed on the other surface of the film base material 1.

〔Effect of the invention〕

As described above, the present invention forms a transparent hydrophilic treatment layer on the transparent conductive thin film provided on one side of the film base material, and furthermore forms the above-mentioned transparent layer on the other side of the film base material. By using a similar hydrophilic treatment layer,
A transparent conductive material that can significantly improve the wettability of various laminates provided on the surface of the thin film and base material, and also improve the scratch resistance, heat resistance, and transparency of the surface of the thin film and base material. can provide a sex film.

The transparent conductive film of the present invention can be used for various purposes such as offset, gravure, screen, and letterpress printing, as well as ultra-high precision printing using various oil-based and water-based inks in printing methods. Enables coating. In addition, the antistatic effect of the conductive thin film enables various improvements such as preventing double feeding during printing, increasing printing speed, and preventing deposits on the film, and is useful in information related fields such as cards, labels, and OHP. It can also be used for film.

〔Example〕

EXAMPLES Below, examples of the present invention will be described in more detail.

Example 1 Polyethylene terephthalate (hereinafter referred to as
Both sides of the PET film are coated with 80% arbon gas.
and 20% oxygen gas.
High frequency sputter etching treatment was performed in an atmosphere of 3 W·sec/- in a discharge treatment amount.

After that, one side of this treated surface was coated with a 400mm thick layer by reactive sputtering using an indium-tin alloy.
We created a transparent conductive thin film made of a composite oxide thin film of human indium oxide and tin oxide (hereinafter referred to as an ITO thin film).

Next, on this conductive thin film, Sigh was vacuum-deposited using an electron beam heating method at a vacuum degree of (1 to 2) A hydrophilic treatment layer was used. Then this P
On the other side of the ET base material, a hydrophilic treatment layer consisting of a 5iOz thin film was formed to the same thickness under the same conditions as above to obtain a transparent conductive film having the structure shown in the figure.

Example 2 A transparent conductive film having the structure shown in the figure was produced in the same manner as in Example 1, except that the transparent hydrophilic treatment layer S i O and the thickness of the thin film were changed to 100 on both sides. .

Example 3 SiO was vacuum-deposited on the ITO thin film and on the surface of the PET substrate by electron beam heating at a vacuum degree of (2 to 5) A transparent conductive film was produced in the same manner as in Example 1, except that a hydrophilic treatment layer was used.

Example 4 Instead of making an ITO thin film, a thickness of about 1
A transparent conductive film was produced in the same manner as in Example 1, except that a transparent conductive thin film consisting of 20 Ag thin films was used.

Comparative Example 1 A transparent conductive film was produced in the same manner as in Example 1, except that the formation of the SiO□ thin film as the transparent hydrophilic treatment layer was omitted.

Comparative Example 2 A transparent conductive film was produced in the same manner as in Example 4, except that the S i Oz thin film as the transparent hydrophilic treatment layer was omitted.

Next, for each transparent conductive film of the above Examples and Comparative Examples, film resistance, transmittance, heat resistance, scratch resistance, water contact angle, surface wettability, Ag paste adhesion, and resist adhesion. , the adhesion of the EL layer, and the adhesion of the ECD layer were measured and evaluated in the following manner. The results are shown in the first section below.
Shown in the table.

<Film resistance> Using the four-probe method, calculate the surface electrical resistance of the film (Ω/mouth).
was measured.

<Transmittance> Visible light transmittance at a light wavelength of 550 nm was measured using a spectroscopic analyzer UV-240 manufactured by Shimadzu Corporation.

<Heat resistance> The transmittance was measured in the same manner as above after being left in an atmosphere at 120° C. for 500 hours using a dryer.

Scratch resistance〉 Hayton surface property measuring machine TYPE-HEI manufactured by Shinraikagakusha
Using DON14, ■Abrasion: Gauze (Japanese Pharmacopoeia type■-), ■Load: 100g/cj, ■Abrasion speed: 3
After rubbing the surface of the conductive thin film under the conditions of 0cm/min, Number of scratches: 100 times (50 round trips), the film resistance (R
The scratch resistance was evaluated by measuring the change rate (Rs/RO) with respect to the initial film resistance (Ro).

Further, after rubbing the surface of the base material opposite to the surface of the conductive thin film under the same conditions as above, the state of surface scratches was visually observed, and the following evaluation was performed.

O: No surface scratches are seen △: Very few surface scratches are seen ×: Very many surface scratches are seen Water contact angle〉 CNTACT-ANGLEMETE manufactured by Kyowa Interface Science ■
The contact angle [θ] between the conductive thin film surface and the opposite substrate surface was measured using R (type CA-DT).

Surface Wettability> The wettability index (surface energy: dyne/cm) of the surface of the conductive thin film and the surface of the substrate on the opposite side was measured using a standard wettability index solution manufactured by Wako Pure Chemical Industries, Ltd.

<Adhesion of Ag Paste> Ag paste 62901 0275 manufactured by Demetron was screen printed on the surface of the conductive thin film to a thickness of about 25 μm, and after curing at 120°C for 50 minutes, 1 was applied to the Ag paste film.
A crosscut with an angle of fi was made, an adhesive tape Na31B manufactured by Nitto Denko ■ was adhered thereto, and the number of remaining crosscuts among 100 crosscuts when strongly peeled off was determined.

<Resist adhesion> NAZ-BAR231 manufactured by Yoshikawa Kako ■ was screen printed on the surface of the conductive thin film, and after curing at 120°C for 2 to 3 minutes, the surface condition was visually observed and evaluated as follows. did.

Repellency is observed in a part of the Δni resist layer <Adhesion of EL layer> A coating liquid made by dispersing zinc sulfide and manganese powder in cyanoethylated cellulose is applied to the surface of the conductive thin film, dried, Embodying an EL light-emitting layer with a thickness of several tens of micrometers,
The following evaluation was performed.

○: Good wettability with the conductive thin film Δ: Repellency is observed in a part of the EL light-emitting layer After applying a polyion complex of lolinsulfonic acid and a polymeric quaternary ammonium salt to the surface of the conductive thin film, the same evaluation as in the case of the EL layer described above was performed.

As is clear from the results in Table 1 above, the transparent conductive film of the present invention has good wettability on the surface of the conductive thin film and the surface of the base material, and has excellent adhesion of various laminates thereon. Moreover, the scratch resistance of the surface of the conductive thin film and the surface of the base material is also improved, and it can be seen that the heat resistance and transparency are also satisfactory.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the transparent conductive film of the present invention. ■... Film base material, 2... Conductive thin film, 3.4.
・Hydrophilic treatment layer

Claims (3)

[Claims] (1) A transparent conductive thin film and a transparent hydrophilic treatment layer are laminated in this order on one side of a transparent film base material, and a hydrophilic treatment layer similar to the above is formed on the other side. A transparent conductive film characterized by: (2) The transparent conductive film according to claim 1, wherein the contact angle [θ] of water on both surfaces of the film is 20 degrees or less. (3) Claim (1) wherein the hydrophilic treatment layer comprises a silicon oxide thin film.
) or the transparent conductive film described in (2).