JPH0556265B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a transparent conductive film for touch panels having surface abrasion resistance and surface antireflection ability. This relates to a film formed on one side and an indium-tin oxide thin film formed on the other side. [Prior art] In recent years, display devices such as CRTs, LCDs, and plasma displays have made remarkable progress, and the importance of touch panels for signal input, which are used in conjunction with these displays, has also increased and is being widely developed. .
This one goes to the IC drive circuit while looking at the display screen.
It is used for the purpose of inputting signals with a finger or pen tip. Therefore, the film used in this case, which has an electrode formed on one side, is constantly subjected to mechanical external force input from the opposite side of the electrode, and is therefore strongly required to have scratch resistance and abrasion resistance. For this reason, it is common to apply a hard coat to the film surface, and a silicone resin hard coat has generally been used. On the other hand, since the film surface is smooth, reflection occurs on the display surface, making it difficult to see the display screen and causing eye fatigue.To solve this problem, a method is to roughen the film surface to the extent that it does not impair the transmitted light. has been achieved. However, with this roughening method, it is difficult to finely adjust the reflectance, and the problem of scratch resistance has not been solved at all. In addition, attempts have been made to add filler for anti-reflection to silicone hard coats, but since there are heat-curable resins, coatings with low reflectance that do not impair transparency are expected to cause filler agglomeration during heating. The current situation is that the product is not available. Furthermore, this method has problems with ink adhesion and ink adhesion when printing fixed characters, etc. on a surface made of silicone resin. [Object of the Invention] The present invention has carried out intensive research in order to obtain an antireflection and hard coat coating film that integrates these two functions, and has developed a monomer-based polyfunctional UV curable resin containing a fine powder filler. The present invention was made based on the knowledge that the present invention is effective for achieving the present object. In other words, anchor coating eliminates the common belief that homopolymerization of polyfunctional monomers cannot achieve adhesion due to curing shrinkage of the resin, which causes particles to be dispersed and unevenness to occur near the particles, and although surface hardness can be obtained due to curing shrinkage. The inventors have discovered that this problem can be eliminated and that a non-reflective anti-reflection layer can be obtained without impairing transparency since fine irregularities can be obtained, leading to the invention of the present application. [Structure of the Invention] The present invention is an ultraviolet curing resin of dipentaerythritol pentaacrylate and/or dipentaerythritol hexaacrylate mixed with finely powdered silica on one side of a transparent film via an anchor layer, and has a haze value of 10. Below, a hard coat layer of a paint film with a pencil hardness of 5H or more is formed on the glass plate,
A transparent conductive film having antireflection properties, characterized in that an indium-tin oxide thin film is formed on the other side of the transparent film via an anchor layer and an ultraviolet curing undercoat layer, and more preferably fine powder. This is a transparent conductive film with antireflection properties in which the surface of silica is treated with an organic substance. As the transparent film used in the present invention, any film with good transparency such as polyester film, polyether sulfonate film, etc. can be used, but polyester film is preferably used in consideration of economic efficiency, mechanical performance, etc. . Next, an anchor coat layer is formed on one side to improve adhesion, and this layer is generally coated with a urethane anchor coat. Since urethane-based anchor coats require time to harden to the touch, it is an effective method to add polyvinyl butyral or the like to enable coating, drying, and winding, and it is also possible to modify them as appropriate. Next, a UV-curable layer containing finely powdered silica is formed, and the formation method is as follows: dilute the polyfunctional monomer increase/decrease agent with a solvent to obtain a varnish, disperse finely powdered silica in the varnish, and apply this on the anchor coated surface. A common method is to remove the solvent and then irradiate it with UV light to cure it. Silica powder is an excellent filler because it is clear with respect to ultraviolet light, so it does not inhibit curing, and because it is a fine powder, it has good dispersion. Fillers whose particle surfaces are treated with an organic substance are also preferably used to improve dispersibility. Although it is the gist of the present invention to use a polyfunctional monomer such as dipentaerythritol pentaacrylate or dipentaerythritol hexaacrylate alone as the ultraviolet curing resin, epoxy acrylate, urethane acrylate, polyester acrylate, etc. It is also possible to use oligomers. Furthermore, an increasing/decreasing agent such as benzoin ethyl ale is used in a conventional manner. In addition, regarding the solvent, the resin system used, the dispersibility of the filler, drying properties,
It is appropriately selected in consideration of filler cohesiveness during drying, etc. The filler-dispersed resin system thus obtained is
It is subjected to UV light irradiation, but during curing, since it is a polyfunctional monomer, curing shrinkage is large and fine irregularities are formed on the surface. Furthermore, this method has the characteristic that coating films with various haze values can be obtained by adjusting the amount of finely powdered silica added, and can overcome the conventional difficulty of obtaining an antireflection layer with a haze value of 10 or less. Note that a haze value of 5 or more decreases the light transmittance and is therefore of little practical significance. Next, an indium-tin oxide thin film is formed on one side of the film by a sputtering method. During the formation, an undercoat layer is formed for the purpose of improving the adhesion between the substrate surface and the indium-tin oxide thin film. The layer is preferably a three-dimensionally crosslinkable resin layer such as a conventional thermosetting resin or ultraviolet curable resin. [Effects of the Invention] The transparent conductive film thus obtained has a high degree of surface scratch resistance, is not damaged at all by steel wool abrasion, and has anti-reflection ability (anti-glare ability), making it a significant conductive film for touch panels. It has a secondary effect of surface printability. [Example] (Formation of anchor layer) 200 parts by weight of polypropylene glycol polyether polyol, 150 parts by weight of diphenylmethane diisocyanate, 150 parts by weight of polyvinylbunaram with a degree of polymerization of 1000, methyl cellosolve acetate.
A uniform anchor coating agent solution was prepared by mixing 1500 parts by weight and 3000 parts by weight of butyl acetate. Anchoring agent was applied to one side of a 150μ thick polyester film using a roll coater method, and then heated at 150°C.
By staying in the drying zone for 5 minutes, a 3 μ thick anchor layer that was touchable was formed. Even when this coated film was left unwound, no blotchigation occurred. (Formation of antireflection and hard coat layer) Dipentaerythritol hexaacrylate
250 parts by weight, 750 parts by weight of methyl cellosorg, and 10 parts by weight of benzoinsopropyl ether were mixed to form a uniform solution. When a surfactant-treated finely powdered silica having an average particle size of 0.5 μm was added to this solution in the amount shown in Table 1 and stirred, a coating agent in which finely powdered silica was uniformly dispersed was obtained. The above-mentioned silica dispersion coating agent was applied using a roll coater method onto the anchor layer of the polyester film on which the anchor layer was previously formed, and after being left in a drying zone at 80°C for 5 minutes, it was heated in a high-pressure mercury furnace at 80W/cm. The coating layer was cured by passing at a speed of 1 m/min at a distance of 15 cm from below. This coat layer had fine irregularities on the surface, was coated with an antireflection agent, and was not scratched even when repeatedly rubbed with Thrill wool. Table 1 shows the optical properties of the film for each amount of silica added.

[Table] (Formation of transparent conductive layer) The anchor coating agent was coated in the same manner as before on the surface of the polyester film opposite to the antireflection/hard coat layer. Next, a solution consisting of 200 parts by weight of bisphenol A type solid epoxy acrylate, 100 parts by weight of pentaerythritol tetraacrylate, 10 parts by weight of benzoin isopropyl ether, 200 parts by weight of methylcellosorg acetate, and 500 parts by weight of butyl acetate was rolled onto the anchor coat layer. Apply by coater method, 80℃
80W/cm after staying in the drying zone for 5 minutes
The coating layer was cured by passing it under a high-pressure mercury lamp at a distance of 15 cm at a speed of 1 m/min. Next, a transparent conductive layer made of indium-tin oxide was provided on the above coating layer by sputtering. The initial resistance value of the obtained conductive layer was 300Ω/hole.

Claims (1)

[Claims] 1. An ultraviolet curing resin of dipentaerythritol pentaacrylate or/and dipentaerythritol hexaacrylate mixed with finely powdered silica on one side of a transparent film via an anchor layer, with a haze value of 10 or less, Pencil hardness on glass plate
Antireflection ability characterized by forming a hard coat layer of 5H or more coating film, and forming an indium-tin oxide thin film on the other side of the transparent film via an anchor layer and an ultraviolet curing undercoat layer. A transparent conductive film with 2. A transparent conductive film having antireflection ability according to claim 1, wherein the surface of the finely powdered silica is treated with an organic substance.