JP2546349B2 - Transparent conductive laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transparent conductive laminate, and more specifically, a transparent conductive layer suitable for use in a display device such as electroluminescence (hereinafter referred to as EL). The present invention relates to a flexible laminate.

[Prior Art] Conventionally, as an EL such as an organic dispersion type, a laminated body composed of a transparent base material and a transparent conductive layer is used as a base, and a light emitting layer, a dielectric layer and a back electrode (on the transparent conductive layer). Metal foil or the like) is formed in sequence, or the light emitting body layer of a laminate formed of a preformed light emitting body layer, a dielectric layer and a back electrode is bonded to the transparent conductive layer by a laminating method, and then the whole is transparent. It is known that it is formed by coating with a moisture-proof layer.

[Problems to be Solved by the Invention] However, in the case of such a conventional technique, the adhesiveness between the transparent conductive layer of the transparent conductive laminate and the light-emitting body layer to be joined is not always sufficient, so that the cutting step such as punching often occurs. There has been a problem that the bonding interface between the transparent conductive layer and the light emitting layer peels off at the end. In addition, even if there is no defect of poor adhesion in the manufacturing stage, there is a problem that durability is poor such that the interface edge is often peeled off and uneven brightness occurs because it is subjected to repeated stress such as bending during use. Therefore, there are problems such as limited applications or special consideration in use, and an urgent and drastic solution has been demanded.

The present invention was devised in view of the drawbacks of the conventional technology, and its purpose is to bond an extremely high adhesive force to another laminate such as an electrode of various display bodies, especially an EL light emitting layer. Another object of the present invention is to provide a transparent conductive laminate that can be obtained.

[Means for Solving the Problems] The object of the present invention is to provide a transparent substrate (A),
A transparent conductive laminate in which the transparent conductive layer (B) and the cellulose-based easy-adhesion layer (C) are laminated in this order or platinum between the transparent conductive layer (B) and the cellulose-based easy-adhesion layer (C) And / or a transparent conductive laminate having an adhesive layer (D) made of palladium.

Transparent base material (A) used in the present invention
As the above, various known polymer resin films can be used. Examples of the material for the resin film include polyester, polyolefin, vinyl resin, polyimide, polyamide and cellulose derivatives.

As the transparent conductive layer (B) formed on the base material (A), known materials can be used, and examples thereof include indium oxide, tin oxide, a mixture of indium oxide and tin oxide, gold, silver,
Examples include simple substances or mixtures of copper, aluminum, platinum and the like, or a laminate of these. The thickness of the conductive layer is not particularly limited, but in order to set the light transmittance to 40% or more,
It is preferably set to 10Å to 5000Å.

The cellulose-based easy-adhesion layer (C) formed on the transparent conductive layer (B) is capable of specifically and dramatically increasing the adhesive force, particularly when bonded to the light-emitting layer.

Examples of the material of the cellulose-based easy-adhesion layer that can be used in the present invention include, for example, esters such as nitrocellulose, acetylcellulose, cellulose acetate butyrate and sesrose acetate propionate, or mixed esters thereof, ethyl cellulose, hydroxyethyl cellulose, Examples thereof include ethers such as cyanoethylated cellulose and carboxymethyl cellulose, and mixed ethers thereof. One or more of these are dissolved in a solvent such as acetone, and this is coated and dried to form a cellulose-based easy-adhesion layer ( C) is formed.

The thickness of the cellulosic easy-adhesion layer (C) is not particularly limited, but is selected in the range of 10Å to 10000Å in order not to impair the characteristics of the transparent conductive layer and to improve the adhesiveness with the light emitting layer. Is more preferable, and more preferably 10Å to 3000Å.

A metal layer (D) made of platinum and / or palladium can be further provided between the conductor layer (B) and the cellulose-based easy-adhesion layer (C). In this case, the layers (B) and (C) The adhesiveness of can be further improved.

The thickness of the metal layer (D) is not particularly limited, but 3Å ~ 30
It is preferable to select in the range of Å, more preferably in the range of 3Å to 15Å.

As the forming method for forming the transparent conductive layer (B) on the base material (A) or forming the metal layer (D) on the transparent conductive layer, there are conventionally known vacuum deposition method, sputtering method and It can be performed by an ion plating method or the like.

The cellulose-based easy-adhesion layer provided on the transparent conductive layer (B) or the metal layer (D) can be formed by a known coating method such as a gravure coating method or a reverse coating method.

[Examples] The present invention will be described below with reference to examples. The characteristic values in the examples are measured by the following methods.

(1) Visible light transmittance Using a haze meter (SEP-HS manufactured by Nihon Seimitsu Optical Co., Ltd.), the visible light transmittance was measured with an integrating sphere that was completely diffused at a transmission center wavelength λ = 550 nm by a G filter. did.

(2) Surface electric resistance value Place a sample cut to a width of 3.5 nm on a rubber sheet of rubber hardness (according to JIS K 6301-1975) of about 60, and put it in 2 mm.
Place a measurement electrode with a thickness of 35 mm palladium plate at an interval of 35 mm in a position orthogonal to the sample, apply a load of 500 g, and use a digital tester (VOAC707 manufactured by Iwasaki Communication Equipment) to measure the resistance value between the terminals. Directly read the value.

(3) Place the adhesive EL sample with the transparent conductive laminate side up, cross-cut 1 mm square from above in the thickness direction, and then stick Nichiban "Cellotape" NO405 on this cut. Then, the end of the cellophane tape was held and a peeling test was conducted in the direction of 180 °, and the grade was judged in the following 5 stages.

Grade 5: No peeling of the interface between the conductive laminate and the luminescent layer (Peeling only Cellotape from the EL sample) Grade 4: 25% or less of the peeling between the conductive laminate and the luminescent layer Class 3: 50% or less of the peeling of the interface Grade 2: Interfacial peeling 75% or less Grade 1: Over 75% -Whole face peeling (Whole face peeling at the interface between the conductive laminate and the light emitting layer) (4) Thickness measurement Fix the sample with wax or the like and cross section with a microtome. It was cut into thin pieces, and the thickness was measured by microscopic observation (photograph).

Example 1, Comparative Example 1 Biaxially stretched polyethylene terephthalate film (Toray Industries, Inc. "Lumirror" thickness 75 μm, visible light transmittance
88%) was deposited with an indium tin compound having a composition of In ₂ O ₃ / SnO ₂ = 90/10 by a sputtering method. Sputtering was carried out at a vacuum degree of 10 ⁻³ Torr with the introduction of argon gas. The deposited film thickness was 400Å. The transparent conductive film thus obtained had a visible light transmittance of 84% and a surface electric resistance of 300 Ω / □.

Then, on the obtained transparent conductive layer, cellulose acetate having an acetylation degree of 55% (manufactured by Daicel Chemical Industries Ltd., cotton acetate L-3
0) 150 g was dissolved in a mixed solvent consisting of acetone / dimethylformamide (1/1 weight ratio) to form a paint, which was applied and laminated by a gravure coating method under a drying condition of 150 ° C./2 minutes. The coating thickness of cellulose acetate was 1000Å.

The transparent electroconductive laminate thus obtained had a visible light transmittance of 84% and a surface electric resistance of 300 Ω / □.

Next, a cyanoethylated cellulose / barium titanate dielectric powder = 50/50 (wt%) was dispersed into an aluminum foil (back electrode) having a thickness of 70 μm with an acetone-based solvent to form a dispersion paint,
It was applied by a screen printing method and applied and laminated at a drying condition of 100 ° C./2 minutes. The thickness of the dielectric layer was 50 μm. Subsequently, a luminescent powder mainly composed of cyanoethylated cellulose / zinc sulfide = 80/20 (wt%) was applied as a dispersion paint on the dielectric layer with the same mixed solvent as described above, and was applied by a screen printing method and dried. The laminate was coated and laminated under the condition of 150 ° C./5 minutes to prepare a luminous body laminate. The thickness of the light emitting layer was 60 μm.

Then, the cellulose acetate layer of the transparent conductive laminate and the luminescent layer of the luminescent laminate were laminated at 170 ° C. by a roll laminating method to obtain an EL. When the obtained EL was observed, the adhesiveness on the laminated surface was grade 5, and was good. Further, even after the predetermined post-processing such as punching, no peeling or missing of the light emitting layer was observed, and it was possible to obtain an EL having high quality and excellent durability.

On the other hand, the EL obtained by the same method as above except that cellulose acetate was not used was evaluated in the same manner, and the adhesiveness was grade 3, and peeling was observed in the post-processing.

Example 2 and Comparative Example 2 Example 1 was repeated except that a palladium layer having a film thickness of 10 Å was formed between the transparent conductive layer and cellulose acetate.
A transparent conductive laminate was obtained in the same manner as. The palladium layer was formed on the transparent conductive layer by a vacuum method with a vacuum degree of 10
^It was carried out at ^-3 Torr with the introduction of argon gas.

The visible light transmittance of the obtained transparent conductive laminate is 82%,
The surface electric resistance value was 300Ω / □.

When an EL was produced using the above transparent conductive laminate in the same manner as in Example 1, the adhesiveness of the laminate surface was grade 5, and a good EL could be obtained.

On the other hand, when the EL obtained by the same method as above was evaluated in the same manner except that cellulose acetate was not used, the adhesiveness was grade 2, and peeling in post-processing was observed.

As is clear from the above results, the transparent conductive laminate of the present invention has extremely excellent adhesiveness to the EL light emitting layer.

EFFECT OF THE INVENTION The transparent conductive laminate of the present invention is an electrode for a liquid crystal display device,
Electrodes for electroluminescent display devices, which can be effectively used in various display devices and known applications such as electrodes for photoconductive photoreceptors, especially when used as an electrode for electroluminescence, the transparent of the present invention By bonding the cellulosic layer of the electroconductive laminate with the EL light-emitting layer, the adhesive strength of the EL layer could be dramatically increased, and EL with high quality and significantly improved durability could be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H05B 33/28 H05B 33/28

Claims (2)

(57) [Claims] 1. A transparent conductive laminate comprising a transparent substrate (A), a transparent conductive layer (B) and a cellulose-based easy-adhesion layer (C) which are laminated in this order. 2. The transparent conductive laminate according to claim 1, further comprising an adhesive layer made of platinum and / or palladium between the transparent conductive layer (B) and the cellulose-based easy adhesion layer (C).