JPH02273409A - Transparent conductive laminate - Google Patents

Abstract

PURPOSE:To improve a scratch-proofing property, a printing characteristic and visualization by a method wherein a substance having the specific thickness as a film base material to form a transparent conductive thin film on one side surface thereof and a transparent body having a water-repellent and stain- preventive treatment layer on the outer surface is pasted up on the other side surface through a transparent adhesive layer. CONSTITUTION:A substance having the specific thickness is used as a film base material 1 to form a transparent conductive thin film 2 on one side surface thereof while a transparent base body 4 having a water-repellent and stain preventive treatment layer on the outer surface is pasted up on the other side surface through a transparent adhesive layer 3. Various kinds of plastic films having transparency are used as a film base body. The thickness of these film base materials shall be 2 to 120mum. A vacuum evaporation method, a sputtering method and an ion plating method is used as a formation method of the transparent conductive thin film. The thickness of the conductive thin film shall be above 50Angstrom . The adhesive layer of acryl, silicon and rubber is used as the adhesive layer 3, while an elastic modulus thereof shall be 1X10<5> to 1X10<7>dyn/cm<2> and the thickness shall be above 1mum.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a transparent conductive laminate in which a transparent conductive thin film is provided on one side of a film base material, and a transparent substrate is bonded to the other side. Regarding.

[Conventional technology]

In general, thin films that are transparent in the visible light range and have conductivity are used not only as transparent electrodes in new display systems such as liquid crystal displays and electric I-Lormine sense displays, but also in touch panels, as well as for antistatic and electromagnetic wave applications in transparent articles. It is used for purposes such as blocking.

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

For this reason, in recent years, various plastic films made of polyethylene terephthalate film have been used as base materials due to their advantages such as flexibility, processability, impact resistance, and light weight. Transparent conductive thin films have received awards.

[Problem to be solved by the invention]

However, conventional transparent conductive thin films using such film base materials have problems such as poor scratch resistance on the surface of the thin film, and scratches during use that increase electrical resistance or cause wire breakage.

In addition, especially in conductive thin films for touch panels, a pair of thin films facing each other with a spacer in between makes strong contact at the point of pressure applied from one of the base materials, so it is important to have good durability to withstand this. Although it is desired that the transparent conductive thin film has such a characteristic, that is, a dotting point characteristic, the conventional transparent conductive thin film mentioned above has a problem that it is inferior to such a characteristic and its life as a touch panel is shortened.

Furthermore, with conventional transparent conductive thin films of this type, the surface of the film base opposite to the surface on which the conductive thin film is formed is bare, so during use, the surface may be exposed to fingerprints, dirt, or scratches. The problem is that the visibility of the thin film product as a whole is poor due to these factors.

In view of the above-mentioned conventional problems, the present invention aims to improve the scratch resistance, dot characteristics, and visibility of a transparent conductive thin film using a film base material such as a polyethylene terephthalate film.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the inventors used a film base material with a specific thickness to form a transparent conductive thin film on one surface, while forming a transparent conductive thin film on the other surface. By bonding another transparent substrate that has been treated with a specific treatment via a transparent adhesive layer, the scratch resistance and dot characteristics of the thin film surface can be improved, as well as the specific treatment that has been applied to the above transparent substrate. It was discovered that visibility could be significantly improved based on the layers, and this invention was completed.

That is, this invention forms a transparent conductive thin film with a thickness of 50 Å or more on one side of a transparent film base material with a thickness of 2 to 120 μm, and a transparent conductive thin film with a thickness of 50 Å or more on the other side with a transparent adhesive layer interposed therebetween. This invention relates to a transparent conductive laminate formed by bonding together a transparent substrate having a water-repellent and stain-preventing treated layer on its outer surface.

[Structure and operation of the invention]

As the film base material used in this invention, various transparent plastic films can be used, and specifically, polyethylene terephthalate, polyimide, polyether sulfone, polyether ether ketone, polycarbonate, polycarbonate, polycarbonate, etc. Examples include I-cobylene, polyamide, polyacrylic, cellulose propionate, and the like.

The thickness of these film base materials needs to be in the range of 2 to 120 μm, particularly preferably in the range of 6 to 100 μm. If the thickness is less than 2 μm, the mechanical strength of the base material is insufficient, and it becomes difficult to form the base material into a roll shape and continuously form a conductive thin film or adhesive layer thereon. On the other hand, 12
If it exceeds 0 μm, it becomes impossible to improve the scratch resistance and dot characteristics of the conductive thin film based on the cushioning effect of the adhesive layer, which will be described later.

The surface of this film base material is subjected to etching treatment or undercoating treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, etc., so that the conductive thin film provided on the base material The adhesion may be improved. Further, before providing the conductive thin film, 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. As a method for forming the conductive thin film, any conventionally known technique such as a vacuum evaporation method, a sputtering method, an ion blating method, etc. can be employed. Furthermore, the thin film material to be used is not particularly limited; for example, in addition to metal oxides such as indium oxide containing tin oxide and tin oxide containing antimony,
Gold, platinum, palladium, copper, aluminum, nickel, chromium, titanium, cobalt, tin, or alloys thereof are preferably used.

The thickness of this conductive thin film needs to be 50 Å or more; if it is thinner than this, it is difficult to form a continuous film with good conductivity and a surface resistance of 10 3 Ω/mouth or less. On the other hand, if the thickness is too large, the transparency may deteriorate, so a particularly suitable thickness is 100 to 2. It is best to set the number to about OOO people.

In this invention, MgFz, SiO2, Aβ203, '1'' is applied to the surface of the transparent conductive thin film as described above.
A dielectric thin film layer of io, TiOz, ZrOz, etc. may be formed to improve the visible light transmittance or to prevent performance deterioration of the conductive thin film due to oxidation or the like.

On the other side of the film substrate on which such a transparent conductive thin film is formed, a transparent substrate having a water-repellent and anti-chip treatment layer on the outer surface is bonded via a transparent adhesive layer. . When this is pasted together, the above-mentioned adhesive layer is provided on the inner surface of the transparent substrate, that is, the surface opposite to the surface on which the water-repellent and anti-stain treatment layer is provided, and then
The film base materials described in 1 may be laminated together, or conversely, the above-mentioned adhesive layer may be provided on the film base material, and this has a water-repellent and anti-scratch treated layer on the outer surface. Transparent substrates may also be bonded together.

The latter method is more advantageous in terms of productivity because the adhesive layer can be formed continuously by rolling the film base material.

As the adhesive layer, any material can be used without particular limitation as long as it has transparency; for example, acrylic adhesives, silicone adhesives, rubber adhesives, etc. are used. This adhesive layer has the function of improving the scratch resistance and dot characteristics of the conductive thin film provided on one side of the film base material by its cushioning effect after adhesion of the transparent substrate, and is mainly used for this function. From the viewpoint of achieving better performance, the elastic modulus should be set at I x 1.05 to I x 107 dyn.
/Cnt range, thickness], p m or more, usually 5 ~
It is desirable to set it within a range of 100 μm.

” The elastic modulus of No. 1 is I x 1.05dyn/cnt
If it is less than that, the adhesive layer becomes inelastic and is easily deformed by pressure, causing unevenness in the film base material and eventually the conductive thin film, and the adhesive tends to protrude from the processed cut surface. Moreover, the effect of improving scratch resistance and dot characteristics is reduced. On the other hand, the elastic modulus is I
If it exceeds 07 dyn/ct&, the adhesive layer becomes hard and its cushioning effect cannot be expected, so that surface scratch resistance and dot properties cannot be improved.

Further, if the thickness of the adhesive layer is less than 1 μm, the cushioning effect cannot be expected, and therefore, it is impossible to expect improvement in scratch resistance and dot characteristics.

Note that if the thickness is too thick, transparency may be impaired, and good results may be difficult to obtain in terms of workability in forming the adhesive layer, laminating transparent substrates, and cost.

The transparent substrates bonded together through such an adhesive layer provide good mechanical strength to the film base material, and particularly contribute to the prevention of curling. When flexibility is required, the plastic film is usually about 6 to 300 μm, and when flexibility is not particularly required, the plastic film is usually about 0.5 μm.
A glass plate or a film-like or plate-like plastic having a size of about 0.5 to 10 mm is used. Examples of the plastic material include the same materials as the film base material described above.

In this invention, the water-repellent and anti-stain treatment layer provided on the outer surface of the transparent substrate is intended to prevent fingerprints and other stains from forming by imparting water repellency to the surface of the substrate, The formation of this layer also provides good results in preventing surface scratches and reducing glare.

Examples of materials for forming such a ↑Ω water and stain prevention treatment layer include silicone-containing compounds such as a combination of dimethylpolysiloxane and methylhydrodienepolysiloxane containing a hydroxyl group or a vinyl group; In addition to fluorine fiber resins such as polytetrafluoroethylene (tetrafluoroethylene) and polychlorotrifluoroethylene (trifluoroethylene), molybdenum sulfide (Mo
S z ), etc., and these can be used alone or as a compound.

In addition, in order to improve the adhesion and hardness of the treated layer, the above-mentioned materials are further dispersed and bonded to a curable resin such as melanin-based resin, urethane-based resin, alkyd-based resin, acrylic-based resin, silicone-based resin, etc. This may be provided as a cured film layer on the surface of the substrate. Furthermore, the anti-glare effect and scratch resistance may be improved by dispersing silica particles having a particle size of about 2 to 30 μm in such a cured film layer.

The method of forming this water-repellent and anti-stain layer is not particularly limited, and depending on the material used, coating method, spray method, vacuum evaporation method, sputtering method, ion blating method, etc.
It may be formed by any method such as a baking method.

The thickness of such a treatment layer is usually 50 to 100 mm.
The thickness is preferably about 100 to 50 μm. If it is too thin, it will be difficult to form a continuous film, resulting in poor water repellency; if it is too thick, cracks may occur during use.

In addition, prior to forming such a water-repellent and anti-stain treatment layer, the surface to be adhered to, that is, the surface of the transparent substrate, is subjected to pretreatments such as corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, sputter etching treatment, Primer treatment and adhesion-promoting treatment may be performed, thereby increasing the adhesion between the transparent substrate and the water-repellent and stain-prevention treatment layer.

Figures 1 and 2 show two examples of the transparent conductive laminate of the present invention, and in both figures, 2 is a transparent conductive layer provided on one side of the transparent film base 1. The thin film 4 is a transparent substrate bonded to the other side of the base material 1 via a transparent adhesive layer 3, and the exposed surface is coated with the above 18.
A water and stain prevention treatment layer 5 has been formed.

In addition to the single-layer structure shown in FIG. 1, the transparent substrate 4 can have a composite structure in which two transparent substrate films 40.4.1 are bonded together with a transparent adhesive layer 30, as shown in FIG. , the mechanical strength of the entire laminate may be further improved. The above base film 40, 41 and adhesive layer 30
For example, materials made of the same materials as those described for the transparent substrate 4 and the adhesive layer 3 are used.

〔Effect of the invention〕

As described above, in this invention, a film base material having a specific thickness is used, and a transparent conductive thin film is formed on one side of the film base material, while an external film is formed on the other side through a transparent adhesive layer. By laminating a transparent substrate with a water-repellent and stain-prevention treatment layer on the surface, it not only improves scratch resistance and dot properties based on the cushioning effect of the adhesive layer, but also provides the water-repellent and stain-prevention properties. The treated layer reduces fingerprints and other stains, and can also be expected to reduce scratches and glare, making it possible to provide a transparent conductive laminate with improved visibility. .

〔Example〕

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

Example 1 Transparent polyethylene terephthalate (2 μm thick)
A reactive sputtering method using an indium-tin alloy on one side of a film base material made of a film (hereinafter referred to as PET) in an atmosphere of 4,X1O-3 Torr consisting of 80% argon gas and 20% oxygen gas. According to
A transparent conductive thin film (hereinafter referred to as an ITO thin film) made of a composite oxide of indium oxide and soot oxide with a thickness of 400 mm was formed.

Next, on the other side of the PET film, a transparent acrylic adhesive layer (with a weight ratio of butyl acrylate, acrylic acid, and vinyl acetate of 1) whose elastic modulus was adjusted to I A film prepared by blending 1 part by weight of an isocyanate crosslinking agent with 100 parts by weight of an acrylic copolymer (OO: 2:5) was formed to a thickness of about 20 μm to obtain a conductive treated film.

On the other hand, polytetrafluoroethylene as a fluororesin was vacuum-deposited on one side of a transparent substrate made of PET film with a thickness of 75 μm at a vacuum degree of lXl0-'Torr, and 1Ω water and A stain prevention treatment layer was formed.

Next, the surface of this transparent substrate opposite to the water-repellent and stain-preventing treated layer is bonded to the conductive treated film via the transparent adhesive layer, thereby creating a transparent structure as shown in FIG. A conductive laminated film was produced.

Example 2 On one side of a transparent substrate made of a PET film with a thickness of 50 μm, Zerflon S (trade name: -1, manufactured by Asahi Glass Co., Ltd.) was applied as a fluorine-containing compound in an acrylic resin diluted with toluene.
A coating solution containing 0.5% by weight of 0.01 (fluorine-based surface modifier) was applied to a thickness of about 7 μm by a coating method and dried to form a 1G water and stain prevention treatment layer. Otherwise, a transparent conductive laminated film having the structure shown in FIG. 1 was produced in the same manner as in Example 1.

Example 3 A silicone-containing compound, trade name KS-770 (silicone mold release agent) manufactured by Shin-Etsu Chemical Co., Ltd., was applied to a thickness of about 0.3 μm by a coating method on one side of a transparent substrate made of a PET film with a thickness of 50 μm. The coating was dried to form a water-repellent and anti-stain layer.

Otherwise, a transparent conductive laminated film having the structure shown in FIG. 1 was produced in the same manner as in Example 1.

Example 4 1. Silica particles having a particle diameter of several micrometers were added together with a fluorine-containing compound to an acrylic resin diluted with luene at a ratio of 7 parts by weight to 100 parts by weight of the acrylic resin. Except for this, a transparent conductive laminated film having the structure shown in FIG. 1 was produced in the same manner as in Example 2.

Comparative Example 1 A transparent conductive film was produced in the same manner as in Example 1, except that the formation of the adhesive layer and the bonding of the transparent substrate having the water-repellent and anti-stain treatment layer were not performed.

Comparative Example 2 A transparent conductive laminated film was produced in the same manner as in Example 1, except that a 75 μm thick PET film without a water-repellent and anti-staining layer was used as the transparent substrate.

Comparative Example 3 A transparent conductive laminated film was produced in the same manner as in Example 2, except that no fluorine-containing compound was added to the acrylic resin diluted with toluene.

Comparative Example 4 A transparent conductive laminated film was produced in the same manner as in Example 4, except that no fluorine-containing compound was added to the acrylic resin diluted with toluene.

Comparative Example 5 A transparent conductive laminated film was produced in the same manner as in Example 1, except that a PET film with a thickness of 125 μm was used as the film base material.

The surface resistance, light transmittance, scratch resistance, dot characteristics and Visibility was examined as follows. The results were as shown in the table below.

<Surface resistance> Film resistance was measured using the four-terminal method.

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

Scratch resistance〉 Hayton surface property measuring device TYPEHEID manufactured by Shinraikagakusha
Using ON14, ■Abrasion: Gauze (Japanese Pharmacopoeia type■), ■Load: 100 g/cI.

■ Scratch speed: 3Qcm/min ■ Number of scratches: 100 times (50 round trips) After rubbing the surface of the conductive thin film, the film resistance (Rs) was measured, and the initial film resistance (Rs) was measured.
Scratch resistance was evaluated by determining the rate of change (Rs/RO) with respect to o).

<Dot characteristics> Two transparent conductive laminated films (or transparent conductive films) with a thickness of 100 meters! The conductive thin films are arranged to face each other through a spacer of 40 mm, and from the side of one film (the transparent substrate or film base material having the ↑Ω water and stain prevention treatment layer) side, the conductive thin films are made of 40 degree hardness urethane rubber. 10 with a load of 100g using a rod (key tip 7R)
After performing 00,000 center hits, the film resistance (R
d) was measured, and the rate of change (Rd/RO) with respect to the initial film resistance (Ro) was determined to evaluate the dot characteristics. The film resistance was measured by measuring the contact resistance of the two transparent conductive laminated films (or transparent conductive films) placed opposite each other at the point of impact.

<Visibility> Transparent conductive laminated film (or transparent conductive film)
The visibility of the entire film was evaluated by examining the water repellency, scratch resistance, and glossiness of the surface opposite to the conductive thin film surface in the following manner.

918 CNTACT-ANGLEMETAR of aqueous consonant interface science
(Format CA'-DT) was used to measure the contact angle θ of water.

An abrasion test was conducted by rubbing with S abrasion steel wool #OOOO, and changes in the surface condition were visually observed and evaluated on the following three levels.

A... Even if you rub it hard, there will be almost no damage B...
C: Scratches occur when rubbed too hard C: Scratches occur when rubbed lightly 9 Glossiness Using a variable angle photometer UGV-5D manufactured by Suga Test Instruments Co., Ltd., 6
The 0 degree gloss was measured.

” - As is clear from the results shown in the table, the transparent conductive laminated film of the present invention provides good visibility based on high light transmittance and the low water repellency and stain resistance of the film backside. At the same time, it can be seen that the scratch resistance and dot characteristics of the surface of the conductive thin film are also very poor.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one example of the transparent conductive laminate of the present invention, and FIG. 2 is a sectional view showing another example of the transparent conductive laminate of the invention. ■... Film base material, 2... Conductive thin film, 3...
Adhesive layer, 4...Transparent substrate, 5...Water repellent and stain prevention treatment layer Patent applicant: Nitto Denko Co., Ltd. Clear IJ layer transparent E body

Claims (2)

[Claims] (1) A transparent conductive thin film with a thickness of 50 Å or more is formed on one side of a transparent film base material with a thickness of 2 to 120 μm, and a transparent conductive thin film is formed on the other side via a transparent adhesive layer. A transparent conductive laminate made by laminating transparent substrates each having a water-repellent and stain-proofing layer. (2) The elastic modulus of the transparent adhesive layer is 1×10^5 to 1×
10^7 dyn/cm^2 and a thickness of 1 μm or more, the transparent conductive laminate according to claim 1.