KR20070042506A - Composite transparent conductive substrate for touch panel and touch panel - Google Patents

Abstract

A substrate (A), a transparent conductive layer (B) and a dielectric layer (C) made of a polymer film or a polymer sheet are laminated in this configuration, and the dielectric layer (C) is an organic polymer having a relative dielectric constant of 15 or more at a temperature of 20 ° C. and a frequency of 1 kHz. The composite transparent conductive substrate for a touch panel having a thickness of 40 nm or more and 2000 nm or less of the dielectric layer C satisfies the characteristics required by the drawing type touch panel.

Description

Composite transparent conductive substrate for touch panel and touch panel {COMPOSITE TRANSPARENT CONDUCTIVE SUBSTRATE FOR TOUCH PANEL AND TOUCH PANEL}

The present invention relates to a composite transparent conductive substrate for a touch panel.

The touch panel is said to be excellent as a man machine interface because it can be used by anyone by simply touching the display of the display. BACKGROUND ART A resistive touch panel is employed as a personal cellular phone information device in which demand is expanding.

The conventional resistive touch panel is a method of pressing operation with a finger, a pen, or the like, a so-called spot method. The main characteristics required for the transparent electrode film (transparent conductive substrate) of the touch panel of this system are (a) prescribed resistance values and uniform resistance values, (b) stability of resistance values at high temperature and high humidity, and (c) It is the spot durability that the change of resistance value by the spot is small. Usually, since the thickness of the transparent conductive layer formed on the transparent conductive substrate is 10 to 40 nm, it is easy to cause deformation, abrasion, crack formation, etc. in the transparent conductive layer due to the spot. Therefore, the most difficult characteristic of the said main characteristic is spot durability, and in order to solve this subject, various technical proposals are made | formed. For example, a transparent conductive laminate in which a transparent conductive layer is formed through an anchor layer containing siloxane bonds having a thickness of 0.02 to 10 µm on at least one surface of a transparent base film has been proposed (Patent Document 1). This method is stable in resistance value under high temperature and high humidity, but its durability is not sufficient. Moreover, the transparent conductive base material which has an electroconductive surface containing an electroconductive polymer is proposed (patent document 2). Although this method is excellent in durability, there exists a problem that resistance value rises under high temperature, high humidity.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-367436

Patent Document 2: Japanese Patent Application Laid-Open No. 2002-109998

In addition to the conventional spotting method, development of the touch panel which can be drawn in recent years is progressing. The main characteristics required for the transparent conductive substrate of the drawing type touch panel are (a) the prescribed resistance value, the resistance value is uniform, (b) the stability of the resistance value under high temperature, high humidity, and (c) drawing. It is drawing durability that there is little change of resistance value by this. Drawing involves plastic deformation and wear of the transparent conductive substrate very largely compared to the RBI because the pen slides the touch panel. In the conventional transparent conductive base material, all of these characteristics could not be satisfied.

The present invention provides a transparent conductive substrate having (a) a prescribed resistance value, a uniform resistance value, (b) a small change in resistance value under high temperature, high humidity, and (c) a small change in resistance value due to drawing. It is.

In the present invention, a substrate (A), a transparent conductive layer (B), and a dielectric layer (C) made of a polymer film or a polymer sheet are laminated in this order, and the dielectric layer (C) has a relative dielectric constant at a temperature of 20 ° C. and a frequency of 1 kHz. The composite transparent conductive base material for touch panels which consist of 15 or more organic polymers, and whose thickness of the dielectric layer (C) is 40 nm or more and 2000 nm or less, and a touch panel using the same.

(Effects of the Invention)

Since the composite transparent conductive base material of this invention is excellent in stability of the resistance value under high temperature, high humidity, and there is little change of the resistance value by drawing, it is excellent as a transparent conductive base material for drawing type touch panels.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the cross section of the composite transparency base material for touch panels of this invention.

It is a schematic diagram which shows the evaluation method of the change of the resistance value by drawing in an Example.

3 is a diagram illustrating a relationship between voltage and linearity measured by the evaluation of FIG. 2.

(Explanation of the sign)

1. Substrate (A) consisting of a polymer film or sheet

2. Transparent conductive layer (B)

3. Dielectric layer (C)

4. Surface hardening layer (D)

In the composite transparent conductive substrate of the present invention, a substrate (A), a transparent conductive layer (B), and a dielectric layer (C) made of a polymer film or a polymer sheet (hereinafter referred to as film / sheet) are laminated in this order.

In addition, a film means here that a thickness is 1 micrometer or more and 500 micrometers or less, and a sheet column thickness exceeds 500 micrometers and is 2 mm or less.

The composite transparent conductive substrate of the present invention is a component used as a transparent electrode of a touch panel. In the resistive touch panel, an upper electrode and a lower electrode are disposed with a predetermined gap. In order to prevent erroneous contact between electrodes, a dot spacer may be formed between upper and lower electrodes. When one point of a touch panel is pressed down, the upper and lower electrodes of the part contact, and it can supply electricity. A potential gradient occurs by applying a voltage to one of the upper and lower electrodes, and the potential of the contact point is detected by detecting the potential at the other electrode. From the relationship between the detected potential and the potential gradient, the coordinates of the contact point are calculated. Due to this mechanism, the transparent conductive substrate is subjected to repeated deformation and stress, and is likely to cause cracks in the transparent conductive layer.

By laminating the dielectric layer (C) made of an organic polymer on the transparent conductive layer (B), cracks are less likely to occur in the transparent conductive layer (B), and the change in resistance value due to drawing is remarkably improved. However, if the transparent conductive layer (B) is covered with an organic polymer, the surface resistance value is markedly high, which is not suitable as a transparent electrode. As described above, when the conductive polymer is used, this problem is solved, but there is a problem that the resistance value rises under high temperature and high humidity. In the touch panel used for outdoor devices such as cellular phone information devices, it is important that the stability of the resistance value under high temperature and high humidity is important. Therefore, both stability of the resistance value under high temperature and high humidity and drawing durability are required.

In the present invention, a high temperature is obtained by laminating a dielectric layer (C) composed of an organic polymer having a relative dielectric constant of 15 or more at a temperature of 20 ° C. and a frequency of 1 kHz and having a thickness of 40 nm or more and 2000 nm or less on the transparent conductive layer (B). It discovered that the composite transparent conductive base material which is excellent in stability of the resistance value under high humidity, and whose change of the resistance value by drawing is few is obtained.

Although the organic polymer having a relative dielectric constant of 15 or higher has a high volume resistivity, when a thin film having an appropriate film thickness is formed on the transparent conductive layer, the surface resistance value of the organic polymer layer changes significantly from the surface resistance value of the transparent conductive layer. It was found that the resistance value within the range suitable for the touch panel was obtained.

As an organic polymer whose relative dielectric constant in temperature 20 degreeC and a frequency of 1 kHz is 15 or more, a cyanoethylated organic polymer is preferable. Among them, cyanoethylated polymers of cellulose-based polymers such as cyanoethyl cellulose and cyanoethyl hydroxyethyl cellulose, cyanoethyl starch, cyanoethylhydroxypropyl starch, cyanoethyl pullulan and cyanoethyl A cyanoethylated polymer of starch-based polymers such as glycidol pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl sucrose, and cyanoethyl sorbitol are selected from one kind or two or more kinds of organic polymers. . Especially, since cyanoethyl pullulan is flexible, since the composite transparent conductive base material with high drawing durability and high stability of resistance value under high temperature, high humidity is obtained, it is especially preferable.

As the organic polymer, acetylated pullulan can also be preferably used. Acetylated pullulan may be used alone or in combination with a cyanoethylated organic polymer to obtain a composite transparent conductive substrate having flexibility, high drawing durability, and high stability of resistance value at high temperature and high humidity. , desirable.

In addition, the thickness of the dielectric layer C is preferably 40 nm or more and 2000 nm or less. If it is less than 40 nm, the improvement effect of stability of the resistance value under high temperature, high humidity is low, and the improvement effect of drawing durability is also not high. If it exceeds 2000 nm, surface resistance value will become large. The more preferable range is 80 nm or more and 800 nm or less.

It is preferable that the surface resistance value of a composite transparent conductive base material is 100 ohms / square or more and 1000 ohms / square or less. When the surface resistance value is less than 100 Ω / □, the power consumption of the touch panel increases. When the surface resistance value exceeds 1000 Ω / □, it is easy to be affected by radio wave disturbances. As for the surface resistance value of a composite transparent conductive base material, it is more preferable that they are 200 ohms / square or more and 500 ohms / square or less. When the thickness of the transparent conductive layer is increased, the surface resistance value is lowered, but the light transmittance is also lowered, and there is a disadvantage that the transparency of the touch panel is deteriorated. 80% or more is preferable and, as for the total light transmittance of a composite transparent conductive base material, it is more preferable that it is 85% or more.

In addition, the surface resistance value here refers to the surface resistance value measured on the dielectric layer (C).

As a film / sheet used as a base material (A), it is shape | molded by resin with high transparency, such as a polycarbonate resin, an acrylic resin represented by acrylic resin, a triacetate, cyclic polyolefin, polyester resins, such as polyethylene terephthalate and polyethylene naphthalate, Film / sheet is preferred. Especially, the film / sheet which consists of polyethylene terephthalate which is high in transparency, high in heat resistance, and flexible is more preferable.

In addition, in order to improve the adhesiveness with the transparent conductive layer (B), before laminating with the transparent conductive layer (B), it is preferable to coat the adhesive resin on the film / sheet or to perform surface treatment such as an electric discharge treatment. Moreover, since a film / sheet may shrink | contract by heat, it is also preferable to heat-process previously, and to remove the distortion which causes shrinkage.

The transparent conductive film layer (B) of the composite substrate for a touch panel of the present invention is a very thin metal thin film such as gold, silver, copper, or indium oxide (may contain tin oxide and / or zinc oxide), tin oxide, and zinc oxide. It is preferable that it is metal type transparent conductive thin films, such as conductive metal oxides, such as these. Especially, the conductive metal oxide with low resistance value in the range with high transparency is more preferable. In particular, one or two or more compounds selected from indium oxide, tin oxide and zinc oxide are preferable because of low surface resistance, high transparency, and little chemical change due to humidity. In addition, the transparent conductive layer (B) may laminate a metal-based transparent conductive thin film in multiple layers.

In the case where a metal-based transparent conductive thin film is used for the transparent conductive layer B, the change in the resistance value under high temperature and high humidity is small, but the change in the resistance value due to drawing is large only in the transparent conductive layer B. However, when the dielectric layer C is laminated on the transparent conductive layer B, the change in the resistance value due to drawing can also be reduced.

These transparent conductive thin films can be formed on the substrate A by a vacuum deposition method called PVD such as electron beam deposition, sputtering, ion plating, or the like. The metal-based transparent conductive thin film is preferably formed by selecting a metal-based transparent conductive material having properties suitable for the intended use and by a suitable thin film production method. In addition, the metal-based transparent conductive thin film can change characteristics such as surface resistance, light transmittance, light reflectance, etc. by heat treatment, and thus may be subjected to heat treatment if necessary. In addition, general physical properties and manufacturing methods of the metal-based transparent conductive thin film are described in Chapters 3, 4, and 5 of `` Technology of Transparent Conductive Films '' (Japan Association for the Promotion of Transparent Oxide Optoelectronic and Electronic Materials, Section 166, Omsa Co., Ltd.). Publication).

In the case where the transparent conductive layer (B) is made of a metal-based transparent conductive material, the thickness thereof should be appropriately determined depending on the surface resistance value and the light transmittance required by the application, but preferably 5 nm to 0.5 μm. In terms of surface resistance, light transmittance, and flexibility, the thickness of the transparent conductive layer (B) is more preferably 10 nm to 0.2 μm. This is because if the thickness is less than 5 nm, the surface resistance is high, and if the thickness is more than 0.5 µm, the surface resistance value is not so low that the light transmittance is lowered due to light absorption of the transparent conductive layer (B).

In addition, a conductive polymer may be sufficient as the raw material of a transparent conductive layer (B). As the conductive polymer, one having a light transmittance of 50% or more at a thickness of 2 μm and a conductivity of 1.0 × 10 ⁻⁸ S / cm is preferable.

Conductive polymers, Conductive Polymers, Chapter 5 (by Yoshino Katsumi, published by Nikkan Kogyo Co., Ltd.) `` Conductive Polymers '' (Naoya Ogata, Published by High Single Inc.) or `` Science and Application of Conducting Polymers '' ( WRSalaneck Op., Published by Adam Hilger).

When the transparent conductive polymer is used for the transparent conductive layer (B), the change in the resistance value due to drawing is small. However, the transparent conductive layer (B) alone has a large change in the resistance value under high temperature and high humidity. By laminating the dielectric layer C on the transparent conductive layer B, the change in resistance value under high temperature, high humidity can be reduced.

More preferred conductive polymers used in the transparent conductive layer (B) are polypyrrole, polythiophene, polyfuran, polyselenophene, polyaniline, polyparaphenylene, polyfluorene, derivatives thereof, and the like, from transparency, conductivity and flexibility. It is any 1 type, or mixture of 2 or more types of conductive polymers chosen from the copolymer of the monomer to comprise. Among them, by introducing a side chain, polythiophene, polyalkyl fluorene, polyfluorene, polyparaphenylene, derivatives of polyparafenylene vinylene having solubility or dispersibility in water or other solvents, and constituting these The at least one conductive polymer selected from the copolymer of monomers is superior in that it is excellent in transparency and conductivity, can be coated on a film / sheet, and can uniformly form a conductive polymer film of appropriate thickness. In particular, a conductive polymer containing polydioxythiophene, especially a conductive polymer composed of a mixture of polyethylene dioxythiophene (PEDT) and polystyrene sulfonic acid (PSS), can be easily dissolved or dispersed in water or other solvents. It is most preferable in that it can coat on a film / sheet, and also can form a film with especially high transparency and electroconductivity. The method for producing a resin liquid in which a conductive polymer composed of polyethylene dioxythiophene and polystyrene sulfonic acid is dissolved or dispersed in water or other solvents is disclosed in Japanese Patent Application Laid-Open No. 7-90060 or International Publication No. 02/067273. Is proposed.

Moreover, since addition of particles, such as polystyrene particle | grains and an acrylic resin particle, to an electroconductive polymer, since activity becomes high, when cutting a film / sheet at a display screen size, it becomes easy to stack | stack the cut film / sheet | seat. . Moreover, since the intensity | strength of the transparent conductive layer (B) becomes strong by adding another resin to an electroconductive polymer, and stability of quality, such as friction and abrasion durability, improves, it is preferable.

The method of laminating the conductive polymer on the substrate (A) includes an electrolytic polymerization method, a vapor deposition method, a coating method (coating method), and the like, and can be appropriately selected according to the use or the kind of the conductive polymer. However, lamination of conductive polymers soluble in water or other solvents by a coating method is more preferable in that it can be laminated uniformly and at a prescribed thickness on a wide, long substrate like a film / sheet. The method of coating is not specifically limited, An appropriate method can be selected according to a use. Various methods of coating are described in detail in the documents such as "Coating Method", Chapters 1 to 18 (manufactured by Harajaki Yuji, Makishoten).

When the conductive polymer is used, the thickness of the transparent conductive layer (B) varies depending on the type of the conductive polymer and should be appropriately determined according to the surface resistance value and the light transmittance, but generally about 400 nm to 5 μm is preferable. More preferable thickness is 500 nm-2 micrometers from the surface resistance value and the point of light transmittance. If the thickness is less than 400 nm, the surface resistance increases, and if the thickness exceeds 5 µm, the light transmittance decreases due to light absorption of the conductive polymer.

Since the touch panel is rubbed with a pen, the touch panel is likely to be damaged. Therefore, it is preferable to form the surface hardness layer (D) on at least one side of the composite conductive substrate. Since the outer surface to be rubbed with the pen is the opposite side to the surface on which the transparent conductive layer (B) / dielectric layer (C) is formed, the surface hardness layer (D) is formed on the surface, and the surface hardening layer (D) It is preferable to laminate in the order of / substrate (A) / transparent conductive layer (B) / dielectric layer (C). Moreover, of the surface hardening layer (D) / base material (A) / surface hardening layer (D ') / transparent conductive layer (B) / dielectric layer (C) which provided the surface hardness layer (D) on both surfaces of the base material (A), You can also choose a configuration.

It is preferable that the said surface hardening layer (D) has hardness of 1H or more of pencil hardness. Although the raw material of a surface hardening layer (D) may be an inorganic compound or an organic compound, since it is flexible, an organic compound is more preferable. As a composition of a surface hardening layer, the ionizing radiation hardening resin etc. which harden | cure by thermosetting resin or high energy ray irradiation, such as an electron beam and an ultraviolet-ray, are mentioned. For example, (meth) acrylate resins, such as a melamine resin, an epoxy resin, pentaerythritol triacrylate, and an acrylate-type alcohol-modified polyfunctional compound, an alkoxysilane compound, a titanate compound, etc. are mentioned preferably. In particular, the (meth) acrylate resin cured by ionizing radiation irradiation is a more preferable composition as the surface hardening layer (D) in terms of high hardness and flexibility. For example, as a composition of such hardening resin, the resin composition of Unexamined-Japanese-Patent No. 12-141556, Unexamined-Japanese-Patent No. 13-179902, Unexamined-Japanese-Patent No. 13-287308, etc. are mentioned.

In general, a transparent conductive film is used as the upper electrode and conductive glass is used as the lower electrode in the touch panel. When the composite transparent conductive substrate of the present invention is used as a transparent conductive film that is an upper electrode, a touch panel excellent in drawing resistance and high temperature and high humidity resistance can be produced. In addition, although development of a thin touch panel is recently examined as a touch panel for mobile phones, etc., when the composite transparency base material of this invention is used as an upper and lower positive electrode, it is possible to produce a thin and light excellent touch panel.

(Example)

〔Assessment Methods〕

1. permittivity

The organic polymer to be measured was dissolved in a solvent containing dimethylformamide as a main solvent, and the solution was applied on a glass plate so as to have a dry thickness of 0.5 mm, and dried and solidified in a 150 ° C. oven for 3 minutes to prepare a plate-like sample. The obtained plate-shaped sample was cut out to 40 mm in all directions, and the electrode DPT-008 for flat plate measurement was attached to the dielectric constant measuring apparatus DT-002 made from Kikomu as an electrode, the sample was stuck to the electrode, and the frequency was 1 kHz and the voltage was 1.0V at a temperature of 20 ° C. The voltage of _DC was applied and it measured according to JIS C6481-1986.

2. Surface Resistance

According to JIS K7194-1994, it measured by the four probe method using the low-resistance meter LELESTA MCP-T360 made from diamond instruments. Four needle-shaped electrodes were placed on a straight line on the dielectric layer of the composite transparent substrate to be measured, a constant current was flowed between the two probes on the outside, and the potential difference generated between the two probes on the inside was measured, and the resistance was calculated. In addition, when measuring the sample which does not form a dielectric layer, the electrode was placed on the transparent electrode.

3. total light transmittance

The composite transparency base material was cut out to 40 mm square, and it measured with the D65 light source using Haze Mater NDH-2000 made from Nippon Denshoku according to JIS K7105-1981.

4. b value

The composite transparent base material was cut out to 40 mm in all directions, and it measured by the transmission method with the D65 light source using SM color computer Model SM-6 made from Sugashi Kenki based on JISK7105-1981.

5. Evaluation of stability of resistance value at high temperature and high humidity

The composite transparent base material was put into 60 degreeC and the constant temperature high humidity tank of 90% RH for 240 hours. The surface resistance value R ₀ before putting into a constant temperature high humidity tank and the surface resistance value R after putting were measured using the evaluation method of 2. mentioned above. By the both non-R / R _0, to evaluate the stability of the resistance value at high temperatures and high humidity. The closer the value of R / R ₀ is to 1, the better the stability of the resistance value under high temperature, high humidity.

6. Evaluation of change in resistance value by drawing

A copper foil tape with an adhesive tape is affixed to the end of the conductive side surface of Esa Glass (manufactured by Touch Panel Co., Ltd.) with spacer particles, a Y electrode and a takeout terminal of the electrode are provided, and a lower electrode (fixed electrode) ) The copper foil tape with an adhesive tape is affixed to the edge of the conductive layer (B) / dielectric layer (C) side surface of the transparent conductive base material of this invention, the X electrode and the extraction terminal of the electrode are provided, and the upper electrode (movable electrode) I did. Moreover, the upper electrode and the lower electrode were opposed to each other so that the conductive side surfaces faced each other, a gap of 80 µm was formed and adhered through a double-sided tape attached to the end, and a touch panel sample was produced. The touch panel sample was placed in a resistive touch panel inspection device (manufactured by Touch Panel Kenkyu Sho), and as shown in Fig. 2, a constant current (I) was flowed using two parallel sides of the upper electrode as the X electrode. Reciprocating a 20 mm long straight line at a speed of 210 mm / min with a polyacetal pen with a pen tip of 0.8 R, on which a pen load of 300 g was applied to the surface hardening layer (D) of the transparent conductive substrate at a position of 2 mm from the end. I took notes. The linearity of the resistance value was measured every 1000 times with one reciprocating drawing. The linearity of the resistance value is called linearity and is calculated by the following equation.

Linearity = (△ E / E) * 100%

Here, E denotes the voltage EX ₁ and the measurement terminal P when the measuring terminal P is on X1 when the both ends of the straight line on which the measuring terminal P is drawn are X1 and X2, respectively. a, X1 and an arbitrary point (X _X) between X2 are calculated by the straight line connecting the voltage (EX ₂₎ the time when the phase voltage is calculated on the in. △ E is _X, as shown in Figure 3, the difference between the actual measured and E _X on the calculation at the point (X _{X) X} EX. The value of linearity is calculated | required by said calculation formula using the largest (DELTA) _EX on the straight line which connects X1 and X2.

The linearity change amount is the difference between the linearity measured at the first drawing time or the linearity measured at every 1000 drawing times. The drawing frequency at which the linearity change amount becomes 1.5% is the maximum drawing frequency. The larger the maximum drawing frequency, the smaller the change in the resistance value due to drawing.

EXAMPLE 1

70 parts by weight of dipentaerythritol hexaacrylate on a substrate (A) using a 125-micron-thick polyethylene terephthalate film (trade name "Lumera (registered trademark)" QT59 manufactured by Toray Industries, Inc.); Surface hardening resin which consists of 16 weight part of macromonomer AN-6S (50 weight% of solid content), 20 weight part of styrene-acryl copolymers (60% of solid content, weight average molecular weight 17790), and 10 weight part of imide acrylate (TO-1429) The solvent dissolved in a solvent containing toluene and methyl ethyl ketone as the main solvent was applied at a coating speed of 10 m / min using three reverse coaters so that the film thickness after drying was 5 µm. After drying in an oven, it was irradiated with a high pressure mercury lamp having an energy strength of 100 w / cm, and the surface cured resin was crosslinked to prepare a surface cured film. An ITO thin film (transparent conductive layer (B)) was formed on the surface opposite to the surface hardened layer (D) of the surface hardened film by using a winding-type DC pulsing magnetron sputtering device so that the surface resistance value was 400? / Sq. did. In addition, the conditions of a sputter | spatter exhaust | exhaust the inside of a sputter | spatter apparatus to a vacuum degree of 4 * 10 <^-3> Pa using the sintering target (99% or more of sintering density) of ITO target (indium oxide (90 wt%) and tin oxide (10 wt%)). Thereafter, an Ar / O ₂ mixed gas of 3.5 mol% of oxygen was introduced thereinto, and the vacuum degree was 4 × 10 ⁻² Pa, followed by sputtering at a substrate speed of 3 m / min.

Subsequently, the film thickness after drying cyanoethyl pullulan (made by Shin-Etsu Chemical Co., Ltd.) which melt | dissolved in the solvent which uses dimethylformamide as a main solvent using the direct gravure head coater on the transparent conductive layer (B) is 0.15 micrometer. The dielectric layer C was formed by apply | coating at the application | coating speed of 30 m / min as much as possible. The relative dielectric constant of cyanoethyl pullulan (Shin-Etsu Chemical Co., Ltd.) used was 19. The touch panel of the present invention laminated in the order of the surface hardening layer (D) / the base material (A) made of the polymer film / transparent conductive layer (B) made of ITO / dielectric layer (C) made of cyanoethyl pullulan A composite transparent conductive base material was prepared. Table 1 shows the results of evaluation according to the above evaluation method.

The touch panel using the composite electroconductive base material of Example 1 satisfy | fills 100,000 times or more which the maximum drawing frequency is a standard of drawing durability, and is excellent in drawing durability.

In addition, the ITO sputtered film has a yellowish color, and there is a strong demand for improvement of light transmittance and color tone. The composite conductive substrate of Example 1 has a light transmittance higher than that of the composite conductive substrate having no cyanoethyl pullulan layer of Comparative Example 1 by laminating a cyanoethyl pullulan layer on the ITO sputter film. The b * value was also lowered. As mentioned above, the composite electroconductive base material for touch panels of this invention can be said to be a more preferable electroconductive base material which is excellent also in an optical characteristic.

Comparative Example 1

The composite transparent conductive layer laminated in the order of the transparent conductive layer (B) which consists of the base material (A) / ITO which consists of surface hardening layer (D) / polymer film similarly to Example 1 except not having formed the dielectric layer (C) The base material was produced. The obtained transparent conductive base material was evaluated according to the said evaluation method. The evaluation results are shown in Table 1.

EXAMPLE 2

Aqueous solution (solid content concentration of 0.7%) of the conductive polymer consisting of polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) on the surface on the side opposite to the surface hardening layer (D) of the surface hardened film produced in Example 1 (Agfa -The brand name: Organacon (trademark) N300 NEW by the Gevaert NV was apply | coated so that the film thickness after drying might be set to 1.2 micrometers, and the transparent conductive layer (B) was formed. The dielectric layer (C) was formed on the transparent conductive layer (B) by coating the cyanoethyl pullulan in the same manner as in Example 1 so as to have a film thickness of 0.12 mu m. The composite of the present invention laminated in the order of the surface hardening layer (D) / base material (A) made of a polymer film / transparent conductive layer (B) made of a conductive polymer / dielectric layer (C) made of cyanoethyl pullulan by the above method. The transparent conductive base material was produced. Table 1 shows the results of evaluation according to the above evaluation method.

The touch panel using the composite conductive substrate of Example 2 satisfies R / R _0? 1.1, which is a standard of resistance value stability under high temperature and high humidity, and is excellent in stability of resistance value under high temperature and high humidity. Moreover, drawing durability is also excellent.

Comparative Example 2

In the same manner as in Example 1 except that the dielectric layer (C) was not formed, a composite transparent conductive substrate composed of a transparent conductive layer (B) made of a substrate (A) made of a surface hardness layer (D) / polymer film / a conductive polymer was prepared. Made. The obtained transparent conductive base material was evaluated according to the said evaluation method. The evaluation results are shown in Table 1.

EXAMPLE 3

When forming the dielectric layer (C), a composite transparent conductive substrate was produced in the same manner as in Example 1 except that acetylated pullulan (manufactured by Hayashi Varajoji) was used instead of cyanoethyl pullulan. The dielectric constant of the acetylated pullulan used was 16. Table 1 shows the results of evaluation according to the above evaluation method.

EXAMPLE 4

When forming the dielectric layer (C), acetylated pullulan (manufactured by Hayashi Barajoji Co.) and cyanoethyl pullulan (manufactured by Shin-Etsu Chemical Co., Ltd.) at a weight ratio of 50% / 50% were used instead of cyanoethyl pullulan. In the same manner as in Example 1, a composite transparent conductive substrate was produced. The relative dielectric constant when acetylated pullulan and cyanoethyl pullulan were mixed in a weight ratio of 50% / 50% was 17. Table 1 shows the results of evaluation according to the above evaluation method.

It can be used as a composite transparent conductive substrate, which is an important constituent member of a touch panel used as an interface required when a human operates an information device.

Claims (9)

A substrate (A), a transparent conductive layer (B) and a dielectric layer (C) made of a polymer film or a polymer sheet are laminated in this order, and the dielectric layer (C) is an organic polymer having a relative dielectric constant of 15 or more at a temperature of 20 ° C. and a frequency of 1 kHz. And the thickness of the dielectric layer (C) is 40 nm or more and 2000 nm or less. The composite transparent conductive substrate for a touch panel according to claim 1, wherein the dielectric layer (C) consists of an organic polymer selected from cyanoethylated polymer and acetylated pullulan. The cyanoethylated polymer according to claim 2, wherein the cyanoethylated polymer is a cyanoethylated polymer of a cellulose polymer, a cyanoethylated polymer of a starch-based polymer, cyanoethylpolyvinyl alcohol, cyanoethyl sucrose, and cyanoethyl sorbitol Composite transparent conductive substrate for a touch panel, characterized in that consisting of one or two or more organic polymers selected from. The composite transparent conductive substrate for a touch panel according to claim 2, wherein the dielectric layer (C) is made of cyanoethyl pullulan. The surface resistance of the composite transparent conductive substrate is 100 Ω / □ or more and 1000 Ω / □ or less, and the total light transmittance of the composite transparent conductive substrate is 80% or more. Composite transparent conductive substrate for touch panel. The substrate (A) made of a polymer film or a polymer sheet is made of a resin selected from polycarbonate resin, acrylic resin, acetate resin, cyclic olefin resin and polyester resin according to any one of claims 1 to 5. Composite transparent conductive base material for touch panels. The composite transparent conductive substrate for a touch panel according to any one of claims 1 to 6, wherein the transparent conductive layer (B) is made of a metallic transparent conductive thin film or a conductive polymer. The composite transparent conductive substrate for a touch panel according to any one of claims 1 to 7, further comprising a surface hardening layer (D) on at least one surface of the substrate (A). The touchscreen composite transparent conductive base material as described in any one of Claims 1-8 was used as one or more electrodes of the upper and lower electrodes.

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