JP2005262442A - Newton ring preventing sheet and touch panel using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Newton ring preventing sheet excellent in Newton ring preventing properties and hard to cause sparkles even when used in a touch panel using a highly detailed color display, and the touch panel using the same. <P>SOLUTION: The Newton ring preventing sheet 1 is constituted so that a Newton ring preventing layer 3 formed of an ionizing radiation-curable organic/inorganic hybrid resin (binder component 32) and fine particles 31 is provided on one side of a transparent support 2 and preferably characterized in that the average particle size of fine particles 31 is 0.5-3.0 μm, the coefficient of variation of a particle size distribution is 20-80% and the thickness of the Newton ring preventing layer 3 is 0.2-3.5 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a Newton ring prevention sheet, and more particularly to a Newton ring prevention sheet used in a touch panel or the like used on a display screen such as a CRT or a flat panel display.

  Conventionally, in the field of photoengraving and optical equipment, there has been a problem caused by Newton's rings that occur due to close contact between members such as plastic films and glass plates. Such a Newton ring can be prevented from occurring by maintaining a gap between the members at a certain level or more when the members are in close contact with each other. There has been proposed a Newton ring prevention sheet in which a Newton ring prevention layer composed of a binder component and fine particles is formed, so that one side or both sides of a member are subjected to uneven treatment (see Patent Document 1).

  On the other hand, in the case of a member such as a film or glass used in a touch panel used on a display screen such as a CRT or a flat panel display, the Newton ring as described above is used to prevent Newton ring generated when touching (pressing) the touch panel. Prevention sheet is used.

  However, as colorization of such CRTs and flat panel displays has progressed, and as the color of various displays has become higher in definition, when a conventional Newton ring prevention sheet is used for a touch panel, it is contained in the Newton ring prevention layer. As the fine particles become bright spots, a glare phenomenon called sparkle occurs, and a problem arises in that a high-definition color screen appears glare.

JP-A-11-77946 (paragraph number 0007)

  Accordingly, the present invention provides a Newton ring prevention sheet that is excellent in Newton ring prevention and is less likely to generate sparkle even when used in a touch panel using a color display with high definition, and a touch panel using the same. For the purpose.

  The Newton's ring prevention sheet of the present invention is characterized by having an ionizing radiation curable organic-inorganic hybrid resin and a Newton's ring prevention layer formed from fine particles on one surface of a transparent support.

  Preferably, the content of the fine particles is 0.1% by weight to 1.0% by weight in the total solid content of the Newton ring prevention layer.

  Preferably, the fine particles have an average particle size of 0.5 μm to 3.0 μm.

  Further preferably, the variation coefficient of the particle size distribution of the fine particles is 20% to 80%.

  Preferably, the Newton ring prevention layer has a thickness of 0.2 μm to 3.5 μm.

  In addition, the Newton ring prevention sheet of the present invention is characterized by having a hard coat layer containing fine particles on the other surface of the transparent support.

  Preferably, the haze in JIS K7136: 2000 is 20% or less.

  Further, the touch panel of the present invention is a resistive film type touch panel that is arranged through a spacer so that the conductive films of a pair of panel plates having a conductive film face each other. Either one or both of the conductive films are formed on the Newton ring prevention layer of any one of the above Newton ring prevention sheets.

  The average particle size and the variation coefficient of the particle size distribution referred to in the present invention are calculated from values measured by a Coulter counter method.

  Moreover, the thickness of the Newton ring prevention layer means the thickness of the resin part in which the convex part is not formed with fine particles.

  According to the Newton ring prevention sheet of the present invention, even when used for a touch panel using a color display with high definition and excellent Newton ring prevention, sparkle hardly occurs, and the color screen looks glaring. Therefore, a touch panel that does not reduce the visibility of the display can be obtained.

  The Newton's ring prevention sheet of the present invention has a Newton's ring prevention layer formed of ionizing radiation-curable organic-inorganic hybrid resin and fine particles on one surface of a transparent support. The Newton ring prevention sheet of the present invention has a hard coat layer containing fine particles on the other surface of the transparent support. The touch panel of the present invention uses such a Newton ring prevention sheet. Hereinafter, embodiments of each component will be described.

  As the transparent support, a highly transparent material such as a glass plate or a plastic film can be used. As the plastic film, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polystyrene, triacetyl cellulose, acrylic, polyvinyl chloride, norbornene compound and the like that can be used can be used and stretched Processing, particularly biaxially stretched polyethylene terephthalate film is preferably used because it is excellent in mechanical strength and dimensional stability. It is preferable to use such a transparent support that has been subjected to an easy adhesion treatment such as a plasma treatment, a corona discharge treatment, a far-ultraviolet irradiation treatment, or an undercoat easy adhesion layer.

  The thickness of the transparent support is not particularly limited and can be appropriately selected depending on the material to be applied. However, in consideration of handling properties as a Newton ring prevention sheet, it is generally about 25 μm to 500 μm, preferably 50 μm. About 300 μm.

  Next, the ionizing radiation curable organic-inorganic hybrid resin used in the present invention will be described. The ionizing radiation curable organic-inorganic hybrid resin used in the present invention is different from the old composites represented by glass fiber reinforced plastic (FRP) in that the organic and inorganic materials are mixed closely and the dispersion state is At or near the molecular level, irradiation with ionizing radiation allows the inorganic and organic components to react and form a coating.

  Examples of the inorganic component of the ionizing radiation curable organic-inorganic hybrid resin include metal oxides such as silica and titania. Among them, those using silica are preferable.

  Examples of such silica include reactive silica in which a photosensitive group having photopolymerization reactivity is introduced on the surface. For example, with respect to powdery silica or colloidal silica as a base, the following general formula is used in the molecule. A compound having four groups of (1) and (2), a hydrolyzable silyl group, and a polymerizable unsaturated group is chemically reacted with the hydrolyzable silyl group via a silyloxy group. Can be used.

（式中、ＸはＮＨ、酸素原子及び硫黄原子から選ばれ、Ｙは酸素原子及び硫黄原子から選ばれる。但し、Ｘが酸素原子のときＹは硫黄原子である。）

(In the formula, X is selected from NH, an oxygen atom and a sulfur atom, and Y is selected from an oxygen atom and a sulfur atom. However, when X is an oxygen atom, Y is a sulfur atom.)

  Examples of the hydrolyzable silyl group include a carboxylylate silyl group such as an alkoxylyl group and an acetoxysilyl group, a halogenated silyl group such as a chlorosilyl group, an aminosilyl group, an oxime silyl group, and a hydridosilyl group.

  Examples of the polymerizable unsaturated group include acryloyloxy group, methacryloyloxy group, vinyl group, propenyl group, butadienyl group, styryl group, ethynyl group, cinnamoyl group, malate group, and acrylamide group.

  Such reactive silica is not particularly limited, but it is preferable to use one having an average particle diameter of 1 nm to 100 nm, more preferably 1 nm to 10 nm. By setting the average particle diameter in such a range, the transparency when the Newton ring prevention layer is formed can be maintained.

  Further, in such an ionizing radiation curable organic-inorganic hybrid resin, the content of the inorganic component is preferably 10% by weight to 50% by weight, and more preferably 20% by weight to 40% by weight. By setting the content of the inorganic component to 10% by weight or more, fine particles described later can be collected on the surface of the Newton's ring prevention layer, and even if the content of fine particles is small, the uneven shape is densely formed on the surface. When the content is 50% by weight or less, it is easy to maintain transparency when a Newton ring prevention layer is formed. That is, when the content of the inorganic component exceeds 50% by weight, the film is easily whitened due to the influence of fine particles, and it becomes difficult to control the optical characteristics and the like when the Newton ring prevention layer is formed.

  Next, as the organic component, a compound having a polymerizable unsaturated group polymerizable with the reactive silica, for example, a polyunsaturated organic compound having two or more polymerizable unsaturated groups in the molecule, or a molecule Examples thereof include monounsaturated organic compounds having one polymerizable unsaturated group.

  Specific examples of the polyunsaturated organic compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, glycerol di (meth) acrylate, glycerol tri (meth) acrylate, and 1,4- Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dicyclopentanyl di (meth) acrylate, pentaerythritol Tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, ditrimethylo Propane tetra (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate and the like.

  Specific examples of the monounsaturated organic compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isodecyl (meth). Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, allyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Hydroxypropyl (meth) acrylate, glycerol (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2- (2 Ethoxyethoxy) ethyl (meth) acrylate, butoxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, 2 -Methoxypropyl (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxytripropylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, etc. It is done.

  In general, a layer formed of ionizing radiation curable resin and fine particles generates “undulations” that are wavy uneven shapes on the surface, so that the size of the fine particles is small and the surface is uneven even if the content is small. The formation of Newton rings can be prevented. The above-mentioned ionizing radiation curable organic-inorganic hybrid resin is a kind of ionizing radiation curable resin, and can generate “swells” on the surface of the Newton ring prevention layer to form irregularities. By using the ionizing radiation curable resin as a binder component in this way, the content of fine particles that cause sparkles can be reduced, so that the occurrence of sparkles can be reduced. On the other hand, however, when “undulation” occurs on the surface of the Newton ring prevention layer, the special surface shape tends to scatter the light of the display image, which tends to induce the generation of sparkles.

  In the present invention, since the Newton ring prevention layer is an ionizing radiation curable organic-inorganic hybrid resin as a binder component, fine particles tend to collect on the surface in the Newton ring prevention layer as described above. In addition to the shape of "", the surface irregularities can be formed densely. Thus, by forming the uneven shape on the surface densely, the scattering of the light of the display image can be reduced, and the occurrence of sparkle can be suppressed. In addition, since the uneven shape of the surface is dense in this way, for example, when having a hard coat layer containing fine particles on the other surface of the transparent support described later, Reflection can be effectively prevented. Furthermore, since the fine particles buried in the Newton ring prevention layer can be reduced, the occurrence of Newton rings can be prevented even if the content of fine particles is smaller than when using ionizing radiation curable resin that is not a hybrid type. Can do.

  In the present invention, by using an ionizing radiation curable organic-inorganic hybrid resin as a binder component, it is possible to make the surface of the Newton ring prevention layer less likely to be scratched even when repeated touching (pressing) or the like is performed. Thereby, when it uses for a touch panel, the raise of the haze by being damaged can be suppressed and the fall of the resolution of the display image of a display can be prevented.

  The surface hardness of the Newton ring prevention layer is not particularly limited and cannot be generally specified because it varies depending on the selected transparent support. However, the pencil hardness in JIS K5600-5-4: 1999 is H or higher, and further 2H or higher. Preferably there is.

  By using the ionizing radiation curable organic-inorganic hybrid resin in this way, the Newton ring prevention sheet of the present invention can be a Newton ring prevention layer with a smaller content of fine particles than when other resins are used, Since the uneven shape can be densely formed on the surface, even when used for a touch panel using a high-definition color display, generation of sparkle can be suppressed, and a touch panel with less glare can be obtained. Moreover, since there is little content of microparticles | fine-particles, it can suppress that transparency when it is set as a Newton ring prevention sheet can also be suppressed, and even if it uses for the above touch panels, a display image can be visually recognized clearly.

  Next, the fine particles used in the Newton ring prevention layer of the present invention will be described. The fine particles are contained in order to prevent the generation of Newton rings by forming convex portions by the fine particles on the surface of the Newton ring prevention layer and causing “undulation” in the Newton ring prevention layer as described above. The type of fine particles is not particularly limited, and inorganic particles such as calcium carbonate, magnesium carbonate, barium sulfate, aluminum hydroxide, silica, kaolin, clay, talc, acrylic resin particles, polystyrene resin particles, polyurethane resin particles, polyethylene Resin particles such as resin particles, benzoguanamine resin particles, and epoxy resin particles can be used. As such fine particles, spherical fine particles are preferably used from the viewpoint of handleability and ease of control of the surface shape, and resin particles are preferably used from the viewpoint of not hindering transparency. Further, in the present invention, fine particles tend to collect on the surface in the Newton ring prevention layer, and this phenomenon occurs particularly remarkably when silica fine particles are used, and it is also preferable to use silica fine particles.

  The size of the fine particles is not particularly limited, but preferably the average particle size of the fine particles is 0.5 μm to 3.0 μm, more preferably 1.0 μm to 2.5 μm. By setting the average particle diameter of the fine particles in such a range, a Newton ring-preventing sheet can be obtained in which the generation of sparkles is further suppressed without lowering the Newton-ring preventing property and transparency.

  Specifically, by setting the average particle diameter of the fine particles to 0.5 μm or more, a convex portion made of the fine particles is formed on the surface of the Newton ring prevention layer to form a concave / convex shape, thereby preventing the occurrence of Newton rings. . Further, by setting the average particle diameter of the fine particles to less than 3.0 μm, the scattering of light of the display image by the fine particles is made smaller than when using fine particles having an average particle diameter of 3.0 μm or more. Therefore, the occurrence of sparkle can be further suppressed.

  Regardless of the size of the fine particles, the variation coefficient of the particle size distribution of the fine particles is preferably 20% to 80%, more preferably 30% to 70%, and still more preferably 40% to 60%. By setting the variation coefficient of the particle size distribution of the fine particles to 20% or more, the light of the display image is uniformly scattered by the fine particles on the surface of the Newton ring prevention layer, unlike monodisperse particles having a uniform particle size. Therefore, the occurrence of sparkle can be more effectively suppressed. In addition, by setting the coefficient of variation of the particle size distribution of the fine particles to 80% or less, it is possible to maintain the transparency and to eliminate fine particles that increase the scattering of light in the display image, thereby further suppressing the generation of sparkles. be able to.

  The variation coefficient of the particle size distribution of the fine particles is a value indicating a variation state of the particle size distribution of the fine particles, and is a percentage of a value obtained by dividing the standard deviation of the particle size distribution by the average particle size {variation coefficient = (Square root of unbiased dispersion) / (arithmetic mean value) × 100%}.

  When the size of the fine particles is within the above range, the thickness of the Newton ring prevention layer is preferably 0.2 μm to 3.5 μm, and more preferably 0.5 μm to 3.0 μm. preferable. By setting the thickness of the Newton ring prevention layer to 0.2 μm or more, it is possible to prevent fine particles from dropping off from the Newton ring prevention layer, and to obtain the minimum required surface hardness. Further, by setting the thickness of the Newton ring prevention layer to 3.5 μm or less, at least some of the fine particles form convex portions on the surface of the Newton ring prevention layer, thereby forming irregularities on the surface, thereby preventing the occurrence of Newton rings. In addition, fine particles having a particle diameter smaller than the thickness of the Newton ring prevention layer can be prevented from being buried in the layer, and the surface irregularities can be formed densely. Thus, since the unevenness | corrugation shape of the surface is formed densely, since scattering of the light of the display image could be canceled, generation | occurrence | production of a sparkle can further be suppressed. The uneven shape of the Newton ring prevention layer is not particularly limited, but Ra in JIS B0601: 2001 is preferably 0.07 μm or more and less than 0.3 μm, and Rsm is preferably less than 150 μm. FIG. 1 shows a sectional view of such a Newton ring prevention sheet of the present invention.

  The thickness of the Newton ring prevention layer is preferably 20% to 80%, preferably 40% to 80% of the average particle diameter regardless of the size of the fine particles. By setting it to 20% or more with respect to the average particle diameter, it is possible to prevent the fine particles from falling off from the Newton ring prevention layer, and to obtain the minimum required surface hardness. In addition, by setting the average particle diameter to 80% or less, the shape when the convex portions by the fine particles are formed on the surface can be made a shape that can cancel the light scattering of the display image. it can. Further, it is possible to form a large number of convex portions due to the fine particles on the surface of the Newton ring prevention layer, and to prevent generation of Newton rings.

  In addition, the thickness of the Newton ring prevention layer means the thickness of the resin part in which the convex part is not formed with microparticles | fine-particles.

  Further, the content of the fine particles is not particularly limited, but is preferably about 0.1 wt% to 1.0 wt% in the total solid content constituting the Newton ring prevention layer. By setting the content of the fine particles to 0.1% by weight or more, good Newton ring prevention properties can be imparted. The reason why the content is 1.0% by weight or less is that, even if it is contained more than that, the Newton's ring preventing property does not change, and only the decrease in transparency and the occurrence of sparkle are caused. Such a Newton ring prevention sheet of the present invention preferably has a haze of less than 3.0% in JIS K7136: 2000.

  Here, for example, when a Newton ring prevention sheet as described above is produced using a thermosetting resin, a thermoplastic resin, or the like as a binder component, as shown in FIG. "Does not occur, it is not possible to obtain the Newton ring prevention effect. Therefore, in order to obtain a shape that prevents the occurrence of Newton rings, the particle size of the fine particles must be increased and the content must be increased. With such a Newton ring prevention sheet, it is possible to maintain transparency and prevent sparkle. Generation cannot be suppressed (FIG. 3).

  In addition, for example, when a non-hybridized ionizing radiation curable resin as a binder component is used for the Newton ring prevention sheet as described above, as described above, “undulation” occurs on the Newton ring prevention layer surface, Generation of Newton rings can be prevented even when the content of fine particles is small (FIG. 4). However, some fine particles do not collect on the surface of the Newton ring prevention layer, but are buried in the layer, and when the ionizing radiation curable organic-inorganic hybrid resin is used, the surface uneven shape is formed more densely. Therefore, it can be set as the Newton ring prevention sheet with the high effect of suppressing sparkle generation. In addition, since the uneven shape of the surface is dense in this way, for example, when having a hard coat layer containing fine particles on the other surface of the transparent support described later, It can be set as a Newton ring prevention sheet with a high reflection prevention effect.

  In addition to the ionizing radiation curable organic-inorganic hybrid resin and fine particles, the Newton ring prevention layer may be other resins, photopolymerization initiators, photopolymerization accelerators, lubricants, fluorescent materials, as long as these effects are not impaired. Brighteners, pigments, antistatic agents, flame retardants, antibacterial agents, antifungal agents, UV absorbers, light stabilizers, antioxidants, plasticizers, leveling agents, flow regulators, antifoaming agents, dispersants, release agents Various additives such as a mold agent and a crosslinking agent can be included.

  Such a Newton ring prevention sheet includes the above-mentioned ionizing radiation curable organic-inorganic hybrid resin, fine particles, and other resins and additives added as necessary, dilution solvent on at least one surface of the above-mentioned transparent support. To prepare a coating solution for Newton's ring prevention layer, and by a conventionally known coating method, for example, bar coater, die coater, blade coater, spin coater, roll coater, gravure coater, flow coater, spray, screen printing, etc. It can be obtained by coating, drying and curing by irradiation with ionizing radiation to form a Newton ring prevention layer.

  As a method of irradiating with ionizing radiation, ultraviolet rays in a wavelength region of 100 nm to 400 nm, preferably 200 nm to 400 nm, emitted from an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a metal halide lamp, etc. are irradiated or scanned. The irradiation can be performed by irradiating an electron beam having a wavelength region of 100 nm or less emitted from a type or curtain type electron beam accelerator.

  Here, in general, a Newton ring prevention sheet for a touch panel is used with a hard coat layer provided on the surface in order to prevent the touched surface from being damaged when the touch panel is used. At this time, there is a problem that light from a fluorescent lamp or the like is reflected.

  The Newton ring prevention sheet of the present invention has a hard coat layer containing fine particles on the other surface of the transparent support described above. By having such a hard coat layer, when it is used as a touch panel, the surface is prevented from being damaged by nails and the like, and the reflection of light such as a fluorescent lamp is effective due to the synergistic effect with the Newton ring prevention layer described above. Can be prevented.

  As the fine particles, the same fine particles as those used in the Newton ring prevention layer described above can be used alone or in combination of two or more. In addition, the size of the fine particles and the coefficient of variation of the particle size distribution are preferably in the same range as described above from the viewpoint of suppressing the generation of sparkles, but are not limited thereto. The content of the fine particles varies depending on the kind of the binder component for containing the fine particles described later and the thickness of the hard coat layer, and is not particularly limited, but is 2 parts by weight with respect to 100 parts by weight of the solid content of the binder component. -20 parts by weight, further 4 parts by weight to 18 parts by weight, more preferably 6 parts by weight to 16 parts by weight. By setting it in such a range, when it is used as a Newton ring prevention sheet, the haze in JIS K7136: 2000 can be 20% or less, and further 10% or less, and it is possible to prevent reflection while maintaining transparency. The effect of can be demonstrated.

  Next, as a binder component for containing fine particles, it is preferable to mainly use a thermosetting resin or an ionizing radiation curable resin, and in particular, the above-mentioned “swell” can be generated, thereby maintaining transparency. However, it is preferable to use an ionizing radiation curable resin in consideration of the point that the reflection preventing property can be imparted and the excellent scratch prevention property can be imparted.

  As the ionizing radiation curable resin, a photopolymerizable prepolymer that can be cross-linked and cured by irradiation with ionizing radiation (ultraviolet ray or electron beam) can be used. As the photopolymerizable prepolymer, 2 per molecule. An acrylic prepolymer having at least one acryloyl group and having a three-dimensional network structure by crosslinking and curing is particularly preferably used. As the acrylic prepolymer, urethane acrylate, polyester acrylate, epoxy acrylate, melamine acrylate, polyfluoroalkyl acrylate, silicone acrylate and the like can be used. Furthermore, these acrylic prepolymers can be used alone, but it is preferable to add a photopolymerizable monomer in order to improve the cross-linking curability and the hardness of the hard coat layer.

  As photopolymerizable monomers, monofunctional acrylic monomers such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, butoxyethyl acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol One kind of bifunctional acrylic monomer such as diacrylate, polyethylene glycol diacrylate, hydroxypivalate ester neopentyl glycol diacrylate, etc., or polyfunctional acrylic monomer such as dipentaerythritol hexaacrylate, trimethylpropane triacrylate, pentaerythritol triacrylate or the like Two or more are used.

  In addition to the above-mentioned photopolymerizable prepolymer and photopolymerizable monomer, the hard coat layer preferably uses additives such as a photopolymerization initiator and a photopolymerization accelerator when cured by ultraviolet irradiation.

  Examples of the photopolymerization initiator include acetophenone, benzophenone, Michler's ketone, benzoin, benzylmethyl ketal, benzoylbenzoate, α-acyloxime ester, thioxanthone and the like.

  Further, the photopolymerization accelerator can reduce the polymerization obstacle due to air at the time of curing and increase the curing speed. For example, p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, and the like. can give.

  Moreover, it is also preferable to use the above-mentioned ionizing radiation curable organic-inorganic hybrid resin as the ionizing radiation curable resin.

  The hard coat layer as described above can contain various additives similar to the Newton ring prevention layer described above as long as the function of the present invention is not impaired.

  Such a hard coat layer is obtained by mixing the above-mentioned fine particles, the binder component, and an additive and a diluting solvent as necessary, on the surface opposite to the surface on which the Newton ring prevention layer of the above-mentioned transparent support is provided. The coating solution for the hard coat layer is prepared, applied and dried by the above-mentioned conventionally known coating method, and cured by heat curing or irradiation with ionizing radiation as described above, if necessary. can do. The Newton ring prevention sheet of the present invention described above may be produced by forming either the Newton ring prevention layer or the hard coat layer first.

  Next, the touch panel of the present invention is a resistive film type touch panel that is arranged through a spacer so that the conductive films of a pair of panel plates having a conductive film face each other, and the conductive film Any one or both of these conductive films are formed on the Newton ring prevention layer of the Newton ring prevention sheet of the present invention described above.

  The conductive film is made of a metal such as In, Sn, Au, Al, Cu, Pt, Pd, Ag, or Rh, or a metal oxide such as indium oxide, tin oxide, or a composite oxide thereof such as ITO. Inorganic thin films with transparency and conductivity, and organic thin films made of aromatic conductive polymers such as polyparaphenylene, polyacetylene, polyaniline, polythiophene, polyparaphenylene vinylene, polypyrrole, polyfuran, polyselenophene, polypyridine, etc. can give.

  As the panel plate, the same transparent support as described in the Newton ring prevention sheet of the present invention, or the Newton ring prevention sheet of the present invention can be used. One surface of the transparent support, or Newton ring On the prevention layer, the above-mentioned conductive film is formed by a vacuum film-forming method such as a vacuum deposition method, a sputtering method or an ion plating method for an inorganic thin film. It is obtained by forming by a coating method. Such a panel plate is preferably subjected to an arbitrary hard coat treatment on the surface to be touched.

  The spacer is formed to secure the gap between the panel plates when a pair of panel plates is used, to control the load when touching, and to improve the separation from each panel plate after touching. The Such a spacer is generally made of a transparent ionizing radiation curable resin, and can be obtained by forming into fine dots by a photo process. Moreover, it can also form by printing many fine dots by printing methods, such as a silk screen, using urethane type resin. It can also be obtained by spraying or applying a dispersion of particles made of inorganic or organic matter and drying. Since the size of the spacer differs depending on the size of the touch panel, it cannot be generally stated, but is generally formed in a dot shape with a diameter of 30 μm to 100 μm and a height of 1 μm to 15 μm, and is arranged at regular intervals of 0.1 mm to 10 mm. .

  As described above, according to the present invention, since it is a Newton ring prevention sheet having an ionizing radiation curable organic-inorganic hybrid resin and a Newton ring prevention layer formed of fine particles on one surface of a transparent support, When used for a touch panel using a color display that is excellent in ring prevention and transparency and has a high definition, a Newton ring prevention sheet that hardly generates sparkle can be obtained. In addition, when a hard coat layer containing fine particles is provided on the other surface of the transparent support, a Newton ring prevention sheet excellent in the reflection of light such as a fluorescent lamp can be obtained. Moreover, since the touchscreen using the Newton ring prevention sheet of this invention does not make a color screen glaring and can be seen, it can be set as the touchscreen which does not reduce the visibility of a display.

  Hereinafter, the present invention will be described in more detail based on examples. In this example, “parts” and “%” are based on weight unless otherwise specified.

1. Production of Newton ring prevention sheet [Example 1]
A coating solution for Newton's ring prevention layer having the following formulation is applied to one side of a 188 μm thick polyester film (Cosmo Shine A4300: Toyobo Co., Ltd.) as a transparent support, dried, and irradiated with ultraviolet light with a high-pressure mercury lamp. A Newton ring prevention layer of .5 μm was formed, and the Newton ring prevention sheet of Example 1 was produced.

<Formulation of coating liquid for Newton ring prevention layer of Example 1>
・ Ionizing radiation curable organic-inorganic hybrid resin 100 parts (solid content 50%) (inorganic component 38%)
(Desolite 7503: JSR Corporation)
・ Fine particles (acrylic resin particles) 0.2 parts (average particle diameter 2 μm) (coefficient of variation 50%)
・ Isopropyl alcohol 150 parts

[Example 2]
The Newton ring prevention of Example 2 is the same as that of Example 1 except that the fine particles of the coating liquid for Newton ring prevention layer of Example 1 are changed to acrylic resin particles having an average particle diameter of 2 μm and a coefficient of variation of 33%. A sheet was produced.

[Example 3]
Example 1 except that the fine particles of the coating liquid for Newton's ring prevention layer of Example 1 were changed to acrylic resin particles having an average particle diameter of 9 μm and a coefficient of variation of 22% to form a Newton ring prevention layer having a thickness of 7 μm. Similarly, the Newton ring prevention sheet of Example 3 was produced.

[Comparative Example 1]
A Newton ring prevention sheet of Comparative Example 1 was produced in the same manner as in Example 1 except that the Newton ring prevention layer coating solution of Example 1 was changed to the Newton ring prevention layer coating solution of the following formulation.

<Prescription of Coating Solution for Newton Ring Prevention Layer of Comparative Example 1>
・ Ionizing radiation curable resin (solid content 100%) 50 parts (Beamset 575: Arakawa Chemical Industries)
・ Fine particles (acrylic resin particles) 0.2 parts (average particle diameter 2 μm) (coefficient of variation 50%)
・ 200 parts isopropyl alcohol

[Comparative Example 2]
Comparative Example 1 except that the fine particles of the coating liquid for Newton's ring prevention layer of Comparative Example 1 were changed to acrylic resin particles having an average particle diameter of 9 μm and a coefficient of variation of 22% to form a Newton ring prevention layer having a thickness of 7 μm. Similarly, the Newton ring prevention sheet of the comparative example 2 was produced.

[Comparative Example 3]
On one surface of the same polyester film as in Example 1, a Newton ring prevention layer coating solution having the following formulation was applied and dried to form a 1.5 μm thick Newton ring prevention layer, and then cured at 60 ° C. for 48 hours. The Newton ring prevention sheet of the comparative example 3 was produced by ringing.

<Prescription of Coating Solution for Newton Ring Prevention Layer of Comparative Example 3>
・ 81 parts of thermosetting resin (acrylic resin) (solid content 50%) (Acridic A807: Dainippon Ink & Chemicals, Inc.)
・ Crosslinking agent (polyisocyanate) (solid content 60%) 16 parts (Takenate D110N: Mitsui Takeda Chemical)
・ Fine particles (acrylic resin particles) 0.2 parts (average particle diameter 2 μm) (coefficient of variation 50%)
・ Methyl ethyl ketone 77 parts ・ Toluene 76 parts

[Comparative Example 4]
Comparative Example 3 except that the fine particles of the coating solution for Newton's ring prevention layer of Comparative Example 3 were changed to acrylic resin particles having an average particle size of 9 μm and a coefficient of variation of 22% to form a Newton ring prevention layer having a thickness of 7 μm. Similarly, the Newton ring prevention sheet of the comparative example 4 was produced.

[Comparative Example 5]
A Newton ring prevention sheet of Comparative Example 5 was produced in the same manner as Comparative Example 4 except that the amount of fine particles added to the coating solution for Newton ring prevention layer of Comparative Example 4 was changed to 5 parts.

2. Fabrication of touch panel (1) Fabrication of panel plate of upper electrode On the Newton ring prevention layer of the Newton ring prevention sheet of Examples 1 to 3 and Comparative Examples 1 to 5, an ITO conductive film having a thickness of about 20 nm is sputtered. Then, a hard coat film (KB film N05S: Kimotosha) is bonded to the other surface via an adhesive to form a 4 type size (87.3 mm long, 64.0 mm rectangular) The upper electrode panel plate was prepared by cutting.

(2) Production of panel plate of lower electrode As a transparent support, an ITO conductive film having a thickness of about 20 nm is formed on one surface of a tempered glass plate having a thickness of 1 mm by a sputtering method. A panel plate of a lower electrode was produced by cutting out a rectangular shape having a size of 87.3 mm and a width of 64.0 mm.

(3) Production of spacer On the surface of the lower electrode panel plate having the conductive film, an ionizing radiation curable resin (Dot Cure TR5903: Taiyo Ink Co., Ltd.) was printed in the form of dots by a screen printing method as a spacer coating solution. Thereafter, ultraviolet rays were irradiated with a high-pressure mercury lamp, and spacers having a diameter of 50 μm and a height of 8 μm were arranged at intervals of 1 mm.

(4) Fabrication of touch panel The panel plate of the upper electrode and the panel plate of the lower electrode are arranged so that the conductive films of each panel plate face each other, and the thickness is such that the bonded portion is outside the area of the display surface. The edges were bonded with a double-sided adhesive tape having a thickness of 30 μm and a width of 3 mm to produce touch panels of Examples 1 to 3 and Comparative Examples 1 to 5.

3. Evaluation About the Newton ring prevention sheet obtained in Examples 1-3 and Comparative Examples 1-5, Newton ring prevention property and transparency were evaluated. Moreover, about the touch panel obtained in Examples 1-3 and Comparative Examples 1-5, the sparkle prevention property was evaluated. The evaluation results are shown in Table 1.

(1) Newton's ring prevention property of Newton's ring prevention sheet Newton's ring prevention layer adhere | attaches the Newton's ring prevention sheet obtained in Examples 1-3 and Comparative Examples 1-5 on the glass plate with a smooth surface. It was put on and pressed with a finger, and whether or not Newton's ring occurred was visually evaluated. In the evaluation, “◯” indicates that no Newton ring was generated, “Δ” indicates that Newton ring was slightly generated, and “×” indicates that Newton ring was generated.

(2) Transparency of Newton Ring Prevention Sheet The haze of Newton ring prevention sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was determined based on JIS K7136: 2000. Measured) and evaluated. In the evaluation, “◯” indicates that the measured value was less than 3.0%, and “x” indicates that the measured value was 3.0% or more. In the measurement, light was incident from the surface having the Newton ring prevention layer.

(3) Sparkle prevention property of touch panel For the touch panels of Examples 1 to 3 and Comparative Examples 1 to 5, the display screen of the CRT display is displayed in 100% green, and the lower electrode side of the touch panel is brought into close contact with the display screen. Evaluation was made visually. In the evaluation, “◎” indicates that there is no glare, “◯” indicates that there is little glare, “Δ” indicates that there is a slight glare, and “×” indicates that there is a large amount of glare.

  As is clear from the results in Table 1, the Newton ring prevention sheets of Examples 1 to 3 used “ionizing” on the surface of the Newton ring prevention layer because the ionizing radiation curable organic-inorganic hybrid resin was used as the binder component. In addition, since the fine particles embedded in the Newton ring prevention layer can be reduced, the Newton ring prevention property is excellent even if the content of the fine particles is small. In addition, since the amount of fine particles that cause sparkle can be reduced in this way, and the uneven shape can be densely formed on the surface, when used for a touch panel using a high-definition CRT color display. In addition, the occurrence of sparkles could be suppressed. Moreover, the touch panel using the Newton ring prevention sheet of Examples 1 to 3 did not cause the color screen to glaring and could be a touch panel that did not reduce the visibility of the display.

  In particular, the Newton ring prevention sheets of Examples 1 and 2 have specific particle size and coefficient of variation, and the thickness of the Newton ring prevention layer, reduce the scattering of light of the display image by the fine particles, and uniformly scatter. In addition, the scattering of light in the displayed image could be canceled out, so that a Newton ring-preventing sheet that is extremely resistant to sparkle was obtained.

  On the other hand, the Newton ring prevention sheet of Comparative Example 1 used an ionizing radiation curable resin that was not a hybrid type as a binder component, and thus “undulation” occurred on the surface of the Newton ring prevention layer. Therefore, the Newton ring prevention property was slightly inferior to the Newton ring prevention sheets of Examples 1 to 3. In addition, since the size and coefficient of variation of the fine particles and the thickness of the Newton ring prevention layer were specified, it had an effect of suppressing the occurrence of sparkle, but as described above, since the binder component was not a hybrid type, the fine particles were Some may not be collected on the surface of the Newton ring prevention layer, but will be buried in the layer, the irregular shape cannot be formed densely on the surface of the Newton ring prevention layer, compared with the Newton ring prevention sheet of Examples 1 to 3. Thus, the effect of suppressing the occurrence of sparkle was low.

  Since the Newton ring prevention sheet of Comparative Example 2 uses an ionizing radiation curable resin that is not a hybrid type as a binder component, as in Comparative Example 1, it has Newton ring prevention properties compared to the Newton ring prevention sheets of Examples 1 to 3. Was slightly inferior. Moreover, in addition to the fact that the irregular shape could not be formed densely on the surface of the Newton ring prevention layer, the use of fine particles with large particle diameters caused a large scattering of light in the display image due to the fine particles, resulting in the generation of sparkles. It became uncontrollable.

  Since the Newton ring prevention sheet of Comparative Example 3 uses a thermosetting resin as a binder component, “undulation” does not occur on the surface of the Newton ring prevention layer, and since the particle diameter of the fine particles is small, the Newton ring prevention effect is obtained. It became impossible. Further, the Newton ring prevention sheet of Comparative Example 3 did not generate sparkle, but the fine particles looked like foreign matters, and the appearance was poor.

  Since the Newton ring prevention sheet of Comparative Example 4 uses a thermosetting resin as the binder component as in Comparative Example 3, no “swell” occurs on the surface of the Newton ring prevention layer, and the content of fine particles is small. The effect of preventing Newton's ring cannot be obtained. In addition, since fine particles having a large particle diameter are used, the scattering of light in the display image by the fine particles is large, and the generation of sparkles cannot be suppressed.

  As in Comparative Example 4, the Newton's ring prevention sheet of Comparative Example 5 used a thermosetting resin as a binder component, so that “undulation” did not occur on the surface of the Newton's ring prevention layer. Since the amount was increased, it was excellent in Newton ring prevention. However, since fine particles having a large particle diameter are used, the scattering of the light of the display image by the fine particles becomes large, and the generation of sparkles cannot be suppressed. Moreover, it became a thing with low transparency.

[Example 4]
In the same manner as in Example 1, a Newton ring prevention layer is formed on one side of the polyester film, the other side is coated with a coating liquid for a hard coat layer having the following formulation, dried, and then irradiated with ultraviolet light with a high-pressure mercury lamp. Then, a hard coat layer having a thickness of about 5 μm was formed, and the Newton ring prevention sheet of Example 4 was produced.

<Prescription of coating liquid for hard coat layer of Example 4>
・ Ionizing radiation curable organic-inorganic hybrid resin 100 parts (solid content 50%) (Desolite 7503: JSR)
-5 parts of fine particles (silica) (average particle size 3.5 μm) (coefficient of variation 60%)
・ Methyl ethyl ketone 40 parts ・ Toluene 15 parts

[Example 5]
A Newton ring prevention sheet of Example 5 was produced in the same manner as in Example 4 except that the hard coat layer coating liquid of Example 4 was changed to the hard coat layer coating liquid of the following formulation.

<Prescription of coating liquid for hard coat layer of Example 5>
・ Ionizing radiation curable resin (solid content 100%) 30 parts (Diabeam UR6530: Mitsubishi Rayon)
・ Fine particles (silica) 1.5 parts (average particle diameter 4.5 μm) (coefficient of variation 60%)
・ Fine particles (silica) (average primary particle size 30 nm) 1.5 parts (Aerosil 50: Nippon Aerosil Co., Ltd.)
-Photopolymerization initiator 0.15 parts (Irgacure 651: Ciba Specialty Chemicals)
・ Methyl ethyl ketone 40 parts ・ Toluene 30 parts

[Comparative Example 6]
In the same manner as in Comparative Example 5, a Newton ring prevention layer was formed on one side of the polyester film, and on the other side, a hard coat layer was formed in the same manner as in Example 4. A sheet was produced.

[Comparative Example 7]
In the same manner as in Comparative Example 5, a Newton ring prevention layer was formed on one side of the polyester film, and on the other side, a hard coat layer was formed in the same manner as in Example 5. A sheet was produced.

[Comparative Example 8]
In the same manner as in Example 4, a sheet of Comparative Example 8 was obtained by forming a hard coat layer on one side of the polyester film and not forming a Newton ring prevention layer on the other side.

[Comparative Example 9]
In the same manner as in Example 5, a sheet of Comparative Example 9 was obtained by forming a hard coat layer on one side of the polyester film and not forming a Newton ring prevention layer on the other side.

  The reflection preventing properties of the sheets of Examples 4 and 5 and Comparative Examples 6 to 9 were evaluated. In the evaluation, each sheet is placed on a black base under a three-wavelength fluorescent lamp so that the hard coat layer is on the upper surface, and the outline of the fluorescent lamp lamp is not reflected, and the outline is reflected almost. “△” indicates that there was not, and “X” indicates that the outline is clearly reflected. The results are shown in Table 2.

  Table 2 also shows the haze of these sheets in JIS K7136: 2000. In the measurement, light was incident from the surface having the hard coat layer.

  Moreover, the touchscreen was produced like the above using the sheet | seat of Examples 4, 5 and Comparative Examples 6-9, and the sparkle prevention property was evaluated. Evaluation criteria were the same as above. The results are also shown in Table 2.

  As is clear from the results in Table 2, the Newton ring prevention sheets of Examples 4 and 5 having the Newton ring prevention layer and Comparative Examples 6 and 7 are those of Comparative Examples 8 and 9 having no Newton ring prevention layer. Examples 4 and 5 which are the Newton ring prevention sheet of the present invention have a specific Newton ring prevention layer as compared with the sheet, and have a specific Newton ring prevention layer. Compared with Comparative Examples 6 and 7 which are layers, the reflection preventing property was excellent.

  Moreover, since the hard coat layer of the Newton ring prevention sheet of Example 4 was less prone to sparkle than the Newton ring prevention sheet of Example 5, the sparkle prevention property was superior to that of Example 5. It was.

  However, in Comparative Examples 6 and 7, as can be seen from the results of Comparative Example 5 in Table 1, sparkle occurs in the Newton ring prevention layer, and thus such a low evaluation regardless of the anti-sparkle performance of the hard coat layer. It became.

Sectional drawing which shows one Example of the Newton ring prevention sheet of this invention Sectional drawing which shows one Example of another Newton ring prevention sheet Sectional drawing which shows the other Example of another Newton ring prevention sheet Sectional drawing which shows the other Example of another Newton ring prevention sheet

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 .... Newton ring prevention sheet 2 .... Transparent support 3 .... Newton ring prevention layer 31 ... Fine particle 32 ... Binder component

Claims (8)

  A Newton ring-preventing sheet comprising an ionizing radiation-curable organic-inorganic hybrid resin and a Newton ring-preventing layer formed from fine particles on one surface of a transparent support.   2. The Newton ring prevention sheet according to claim 1, wherein the content of the fine particles is 0.1 wt% to 1.0 wt% in the total solid content of the Newton ring prevention layer.   The Newton's ring prevention sheet according to claim 1 or 2, wherein the fine particles have an average particle size of 0.5 µm to 3.0 µm.   The Newton's ring prevention sheet according to any one of claims 1 to 3, wherein a variation coefficient of a particle size distribution of the fine particles is 20% to 80%.   5. The Newton ring prevention sheet according to claim 3, wherein a thickness of the Newton ring prevention layer is 0.2 μm to 3.5 μm.   6. The Newton ring prevention sheet according to claim 1, further comprising a hard coat layer containing fine particles on the other surface of the transparent support.   7. The Newton ring prevention sheet according to claim 6, wherein the haze in JIS K7136: 2000 is 20% or less.   A resistive film type touch panel in which a pair of panel plates having a conductive film are arranged via a spacer so that the conductive films face each other, and the conductivity of either one or both of the conductive films A touch panel, wherein the film is formed on a Newton ring prevention layer of the Newton ring prevention sheet according to any one of claims 1 to 7.

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