JP2006161004A - Antistatic filler, antireflective film having this filler, and display filter having this antireflective film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antistatic filler which is suitable for an antireflective film such as a display filter and is excellent in the optical transparency and color reproducibility, and to provide an antistatic layer and hard coat layer which is suitable for an antireflective film such as a display filter and excellent in the workability, optical transparency, and color reproducibility, and also to provide an antireflective film. <P>SOLUTION: The antistatic filler comprises an electroconductive particulate having the proton conductivity, especially comprises antimony oxide particulate having a pyrochlore structure. The antistatic layer and hard coat layer contains a resin dispersed with the above antistatic filler. The antireflective film is such that an interlayer, a hardcoat layer, and a low refractive-index layer with the refractive index smaller than that of the hardcoat layer are on a transparent substrate laminated in order, with the above hardcoat layer being a hardcoat layer containing a resin dispersed with the above antistatic filler. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antireflection film useful for a front filter of a plasma display panel (PDP), a liquid crystal display (LCD) and other displays, an antistatic filler useful for the antireflection film, and a display having the antireflection film. The present invention relates to a front filter.

  In general, a front filter is always used for PDP and LCD. These front filters can cut near-infrared rays, improve color reproducibility (emission color purity improvement), electromagnetic wave shield, improve bright contrast (antireflection), protect the light-emitting panel, block heat from the light-emitting panel, etc. Plays the role of

  It is necessary to reduce the near infrared rays emitted from the light emitting panel of the PDP in order to avoid malfunctioning the remote control used for home television and video. In addition, it is necessary to reduce the electromagnetic waves emitted by the light emitting panel of the PDP in order to avoid adverse effects on the human body and precision equipment. Furthermore, in order to make the light emitted from the light emitting panel of the PDP feel a natural color for human vision, a device for improving color reproducibility (light emission color purity improvement) is also required by correction with a filter. Further, it is desirable that the display on the display is visually recognized with sufficient contrast without being hindered by reflection of light from the outside even in a bright place such as a bright room. Furthermore, even when the display product is directly touched by hand, the heat generated by the light emitting panel of the PDP is required to be cut off in order to avoid a situation where the user is surprised by the high temperature. In order to prevent the product from being easily damaged, it is desirable that the light-emitting panel be protected so that the fragments do not scatter even if it is damaged.

  The structure of a typical front filter for PDP along the above purpose is illustrated in FIG. An antireflection layer 21, an electromagnetic wave shielding layer 22, a color tone correction filter layer 24, and a near infrared cut layer 25 are laminated on a transparent substrate 23, and this is installed as a filter on the front surface of the light emitting panel 20. The order of lamination is changed according to the purpose.

  In this front filter for PDP, the antireflection layer is generally produced as an antireflection film having both light transmittance and antireflection properties, and is used as one layer of the filter. The same applies to the LCD front filter.

  Such an antireflection layer is manufactured as a multilayer laminate (antireflection film) including a plurality of thin layers having different refractive indexes designed to reduce reflected light as much as possible. Although it is possible to produce this multilayer laminate by a dry process such as a vacuum deposition method or a sputtering method, generally this dry process requires a vacuum manufacturing facility, and when mass production is required, Manufacturing costs are inevitably increased. For this reason, the formation of a multilayer laminate of antireflection films by a wet coating method such as solution coating is widely used.

  The general structure of such an antireflection film by wet coating is illustrated in FIG. This antireflection film is obtained by laminating a transparent base material 33 with a high refractive index layer 32 having hard coat properties and a low refractive index layer 31 having a lower refractive index than the high refractive index layer 32. Antireflective properties are imparted by the refractive index layer 31, and it has a role of preventing the visibility from being reduced due to reflection of external light incident from the low refractive index layer 31 side.

  In actual use, dust or the like often adheres to the front surface of the display filter due to charging. The attached dust greatly impairs the optical performance of the display filter. In order to reduce the adhesion of dust and the like, the antireflection film is usually manufactured with further antistatic performance. For example, an antireflection film provided on the surface of the filter is provided with a layer having antistatic properties.

  In order to obtain a layer having antistatic properties, electrical conductivity is usually imparted to the layer. As such a layer, for example, a thin film layer in which conductive metal oxide fine particles such as tin oxide are finely dispersed in a synthetic resin or a surfactant-containing thin film layer is used. Since the antistatic layer made of a surfactant is easily affected by the antistatic performance due to environmental conditions such as humidity, an antistatic layer using conductive metal oxide fine particles which are hardly affected by the environmental conditions is generally preferable.

  In such a case, conductive fine particles such as ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide), tin oxide, etc. are used as antistatic fillers with conductive metal oxide fine particles. .

  For example, Patent Document 1 (Japanese Patent Laid-Open No. 2002-200690) discloses a method in which a hard coat layer, a high refractive index layer, and a low refractive index layer are laminated on an organic film, and the high refractive index layer is made of a conductive material such as ITO or ATO. An antireflection film imparted with an antistatic function by blending metal oxide fine particles is disclosed.

JP 2002-200690 A

  However, the above-mentioned conductive metal oxide fine particles such as ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide), tin oxide, etc. are used as an antistatic filler, for example, an antistatic layer. Alternatively, when the high refractive index layer of Patent Document 1 is provided, there is an inconvenience that the color deviation and the decrease in the light transmittance become conspicuous in accordance with the amount of use and the increase in the thickness of the antistatic layer to be installed. there were. In addition, when these conductive metal oxide fine particles that are usually used are used as antistatic fillers, the refractive index of the layer tends to be relatively large, which causes restrictions on optical design. There was also an inconvenience.

  Furthermore, a so-called hard coat layer usually requires a thickness of about 1 μm to several μm, for example, about 5 μm, in order to achieve the hardness required for its hard coat properties. And when introduce | transducing the filler of electroconductive metal oxide fine particles, such as ITO and ATO, it is preferable also on manufacture operation to introduce | transduce into a hard-coat layer with comparatively thickness. However, when a conductive metal oxide fine particle filler such as ITO or ATO is used as a layer having a thickness of about 5 μm, the transmittance of the antireflection film is lowered and the color is unbalanced. The problem that the reproducibility deteriorated appeared remarkably.

  The occurrence of such a color deviation or a decrease in light transmittance is considered to be because the filler of conductive metal oxide fine particles such as ITO and ATO has light absorption characteristics from the infrared region to the visible light region. In consideration of this characteristic, as long as a conductive metal oxide fine particle filler such as ITO or ATO is used, the filler should be introduced into a layer having a thickness smaller than about 1 μm to suppress the manifestation of light absorption characteristics. Don't be. For this reason, it has been particularly difficult to add a function as an antistatic layer to a high refractive index layer (hard coat layer) having hard coat properties.

  Accordingly, an object of the present invention is a filler suitable for use in an antireflection film useful for a front filter of a plasma display panel (PDP) and other displays, and does not deteriorate light transmission and color reproducibility. An object of the present invention is to provide a filler capable of imparting antistatic properties to the filler, ie, an antistatic filler.

  Another object of the present invention is an antistatic filler as described above, which does not deteriorate the light transmission and color reproducibility even when used in a thick layer such as a hard coat layer. The object is to provide an antistatic filler.

  Still another object of the present invention is to provide an antistatic layer using the above antistatic filler.

  Another object of the present invention is to provide a hard coat layer having an antistatic function using the above antistatic filler.

  Still another object of the present invention is an antireflection film using the antistatic filler described above.

  Furthermore, the objective of this invention is also providing the filter for a display which has said antireflection film.

The present inventors have achieved that the above object is achieved by an antistatic filler comprising conductive fine particles having proton conductivity, and that the fine particles of antimony oxide (Sb ₂ O ₅ ) in which the conductive fine particles have a pyrochlore structure, It has been found that it is particularly suitable as an antistatic filler comprising the above-mentioned conductive fine particles having proton conductivity.

  That is, when the antistatic filler is used, it is possible to obtain an antistatic layer that is excellent in light transmittance and does not cause color deviation. Furthermore, if the antistatic filler is dispersed in a layer and used, even when a layer with a thickness of several μm or more, which is required as a hard coat layer, is formed, the antistatic layer has sufficient light transmittance and color unevenness. Excellent properties that do not cause Thus, if it becomes possible to disperse the antistatic filler in the hard coat layer having a thickness of about several μm, compared with the case where the antistatic filler must be uniformly dispersed in the layer of about several tens of nm. Workability is greatly improved.

  In addition, when the antistatic filler is used for the layer, there is an advantage that the refractive index of the layer is not increased excessively as compared with the filler of conductive metal oxide fine particles such as ITO and ATO. That is, if the antistatic filler is used, an increase in the refractive index due to the use of the filler itself can be reduced, and the degree of freedom in designing the arrangement of the refractive index of the laminated structure can be increased.

  Although the details of the reason why the antistatic filler of the present invention exhibits such excellent properties are not clear, the present inventors consider that the light absorption property by proton conductivity is important. This proton conductivity means the conductivity carried by proton transfer.

  The fillers of conductive metal oxide fine particles such as ITO and ATO, which have been used conventionally for antistatic purposes, correspond to so-called electron conductive fillers that are conductive by electron transfer. Although this has a relatively high conductivity, it is considered that this has a light absorption characteristic from the infrared region to the visible light region. In the present invention, by selecting proton-conductive conductive fine particles as the antistatic filler, the light absorption can be extremely reduced in the visible light region, and the filler exhibits the above excellent characteristics. It is thought that.

Pyrochlore structure refers to a structure similar to pyrochlore. Pyrochlore has the chemical formula of (Na, Ca, U) ₂ (Nb, Ta, Ti) ₂ O ₆ (OH, F), the point group is 4 / m32 / m, the space group is Fd3m, cubic system It is a mineral belonging to. The pyrochlore group (Hylosite group) has a general chemical composition formula of A _{1 to 2} B ₂ O ₆ (O, OH, F) · H ₂ O (where A = Ba, Bi, Ca, Ce, Cs, K, Na, Pb, Sb ⁺³ , Sn, Sr, Th, U, Y, Zr; B = complex cubic oxide having Fe, Nb, Sn, Ta, Ti). In the general formula of A ₂ B ₂ X ₆ X ′, antimony oxide (Sb ₂ O ₅ ) used in the present invention has H as A, Sb as B, and O and OH as X and X ′. Protons derived from water contained in the crystal structure are considered to contribute to proton conductivity.

  Therefore, an antistatic layer having high transparency and little color deviation can be obtained by using the conductive fine particles in the layer as an antistatic filler. That is, the present invention also resides in an antistatic layer containing the above antistatic filler. Furthermore, the antistatic layer comprising the antistatic filler has sufficient light transmission even when used in a relatively thick layer thickness required as a hard coat layer, resulting in color bias. It keeps the advantage of never. That is, the present invention also resides in a hard coat layer containing the antistatic filler. Furthermore, if this hard coat layer is used, the antistatic property can be imparted without adding a new layer, thereby eliminating the adverse effects such as workability, productivity decrease and production cost increase associated with the increase of the new layer. be able to.

  The average particle size of the conductive fine particles is generally in the range of 5 to 300 nm, preferably in the range of 10 to 200 nm, and particularly preferably in the range of 15 to 150 nm. From the viewpoint of transparency, the smaller the particle diameter, the better, but from the viewpoint of the antistatic effect, the larger the particle diameter is preferable.

  In addition, the hard coat layer contains the antistatic filler in a proportion of generally 4 to 85 mass%, preferably 5 to 40 mass%, particularly 6 to 25 mass%, based on the total mass of the hardcoat layer. It is preferable to contain in the ratio of the range of the mass%. From the viewpoint of the antistatic effect, the larger the content ratio of the antistatic filler, the better. However, from the viewpoint of imparting flexibility required for the hard coat layer, the smaller the content ratio, the more preferable.

  The thickness of the hard coat layer is generally from 1 to 10 μm, preferably from 2 to 8 μm, particularly preferably from 3 to 6 μm, as a range that can be formed while taking advantage of the properties of the antistatic filler.

  Therefore, in the antireflection film including the hard coat layer, the function of the antistatic layer can be realized without adding a new layer by adding the function of the antistatic layer to the hard coat layer. That is, this invention exists also in the antireflection film containing said hard-coat layer.

  Then, on the transparent substrate, an intermediate layer, a hard coat layer, and a low refractive index layer having a refractive index smaller than that of the hard coat layer are sequentially laminated, and the antireflection film in which the hard coat layer is an antistatic layer is a hard coat layer. It is one aspect | mode of preferable implementation of the anti-reflective film formed as a layer which provided the function of the antistatic layer. In particular, the hard coat layer is preferably an antireflection film containing a resin in which the above antistatic filler is dispersed.

  Although various materials can be used as the transparent substrate, organic resin polymers are preferable, and polyethylene terephthalate (PET) and triacetyl cellulose (TAC) are included, and particularly PET is transparent and flexible. From the viewpoint of properties and the like.

  The intermediate layer generally has a refractive index in the range of 1.53 to 1.63, preferably in the range of 1.54 to 1.62, particularly preferably in the range of 1.55 to 1.61. The intermediate layer generally has a thickness in the range of 60 to 115 nm, preferably in the range of 63 to 109 nm, particularly preferably in the range of 65 to 103 nm. By setting the values in these ranges, it is possible to realize the interference fringe prevention function in the antireflection function. In particular, when PET (refractive index: 1.65) or a material having a refractive index close thereto is used as the transparent substrate, an excellent interference fringe prevention function can be realized.

  The low refractive index layer preferably contains a resin in which hollow silica is dispersed. By using hollow silica (porous silica), it is possible to achieve both low refractive index and surface hardness. The resin is preferably an ultraviolet curable resin from the viewpoint of hardness.

  As described above, the present invention also resides in an antistatic layer containing the above antistatic filler. The antistatic layer comprises an antistatic filler in a proportion generally in the range of 4 to 85% by weight, preferably in the range of 5 to 40% by weight, in particular 6 to 25% by weight, based on the total weight of the antistatic layer. It is preferable to include it in the ratio of the range. From the viewpoint of the antistatic effect, the larger the content of the antistatic filler, the better. However, from the viewpoint of imparting flexibility required for the antistatic layer, the smaller the content, the better. The thickness of the antistatic layer is generally 1 to 10 μm, preferably 2 to 8 μm, particularly preferably 3 to 6 μm, as a range that can be formed while taking advantage of the properties of the antistatic filler. Furthermore, as described above, the present invention also resides in an antireflection film including the above antistatic layer.

  If an antireflection film having a hard coat layer or an antistatic layer laminated as described above is used, a display filter having excellent antireflection performance, light transmittance, color reproducibility, and the like can be obtained. That is, the present invention is also in a display filter having the antireflection display.

  Furthermore, by installing the antireflection film as the outermost layer, a display filter that exhibits the antireflection performance of the antireflection film and appropriate hard coat properties can be obtained. That is, the present invention also includes a display filter in which the antireflection film is provided as an outermost layer.

  If the antistatic filler of the present invention is used, an antistatic layer excellent in light transmittance and color reproducibility can be obtained. Therefore, the antireflection film using this antistatic layer is one that prevents adhesion of dust and the like by antistatic, and maintains excellent light transmission and color reproducibility while preventing deterioration in optical performance due to adhesion of dust and the like. It is. If this anti-reflection film is used as a front filter for a display such as a PDP or a liquid crystal display, the image on the display is clearly displayed while preventing the visibility from being reduced due to reflection of light from the outside of the display. Moreover, it can be enjoyed with good color reproduction, and further, it is possible to prevent the screen from being blocked or the image from becoming unclear due to dust adhering to the front surface of the display due to charging.

  Further, when the antistatic filler of the present invention is used, an antistatic layer thicker than 1 μm can be obtained while maintaining its excellent light transmittance and color reproducibility. Therefore, this antistatic layer can be formed integrally with a hard coat layer having a desired hardness. Therefore, the antireflection film using this antistatic hard coat layer prevents adhesion of dust and the like by antistatic, prevents deterioration of optical performance due to adhesion of dust and the like, and has excellent light transmission and color reproducibility. While maintaining, it has the advantage that workability in the production process is also improved. And if this anti-reflection film is used as a front filter for a display such as a PDP or a liquid crystal display, in addition to the above-mentioned advantages, the front of the display is not easily damaged, so there is little loss of visibility due to scratches, and it can be handled with confidence A front filter for a display that can be provided can be provided at low cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of an antireflection film including an antistatic layer using the antistatic filler of the present invention. In FIG. 1, by including an intermediate layer 13 having adhesiveness on a transparent base material layer 14 and a resin in which the antistatic filler of the present invention is dispersed while having a certain hardness and a required thickness. An antireflection film is shown in which a hard coat layer 12 imparted with antistatic properties and a low refractive index layer 11 having a refractive index lower than that of the hard coat layer are sequentially laminated. Outside light such as room illumination light is installed so as to enter from the low refractive index layer 11 side. When manufacturing as a filter for a display, various layers are further laminated on the back side of the transparent base material layer 14, for example, a near infrared cut layer, a color tone correction filter layer, an electromagnetic wave shielding layer, or a self-supporting transparent base material. If necessary, it is further laminated via the adhesive layer.

The anti-reflection film having the configuration shown in FIG. 1 realizes anti-reflection performance with a small number of layers because the hard coat layer plays a role of a so-called high refractive index layer, and further reduces interference fringes due to the presence of an intermediate layer. Can be realized. The hard coat layer contains a resin in which an antistatic filler made of conductive fine particles having proton conductivity, particularly, antimony oxide (Sb ₂ O ₅ ) fine particles having a pyrochlore structure is dispersed. As a result, an antistatic layer having high transparency and little color deviation is obtained as an integral layer with the hard coat layer.

  The average particle diameter of the conductive fine particles is generally in the range of 5 to 300 nm, preferably in the range of 10 to 200 nm, and particularly preferably in the range of 15 to 150 nm. From the viewpoint of transparency, the smaller the particle diameter, the better, but from the viewpoint of the antistatic effect, the larger the particle diameter is preferable.

  In addition, the hard coat layer generally contains the antistatic filler in a ratio of 4 to 85% by mass, preferably in the range of 5 to 40% by mass, particularly 6 to 25% by mass with respect to the total mass of the hard coat layer. It is preferable to include it in the ratio of the range of%. From the viewpoint of the antistatic effect, the larger the content ratio of the antistatic filler, the better. However, from the viewpoint of imparting flexibility required for the hard coat layer, the smaller the content ratio, the more preferable.

  The thickness of the hard coat layer is generally from 1 to 10 μm, preferably from 2 to 8 μm, particularly preferably from 3 to 6 μm, as a range that can be formed while taking advantage of the properties of the antistatic filler.

  As the resin in which the conductive fine particles are dispersed, various transparent resins that can be used for the hard coat layer can be used, but a layer made of a cured film of a thermosetting resin or an ultraviolet curable resin is preferable. By using the curable resin, the hard coat layer can be provided on the transparent substrate layer very easily.

  As the thermosetting resin, a thermosetting silicone composition (for example, methyltrimethoxysilane that forms an organic polysiloxane) is preferable, and three-dimensional crosslinking is performed in the dehydration condensation of silanol groups to obtain a high hardness coating. Generally, it can be cured by heating at 80 to 220 ° C. for 10 minutes to 1 hour.

  Further, as the curable resin, a resin or oligomer having an ethylenic double bond (preferably an acryloyl group or a methacryloyl group) can be used, and this can be generally made into a hard coat layer by photocuring.

  Alternatively, the hard coat layer is also preferably a layer made of a cured film of a curable resin containing silica fine particles. In particular, the hard coat layer can be provided on the transparent substrate layer very easily by using an ultraviolet curable resin.

  The primary particle size of the silica fine particles is preferably in the range of 1 to 200 nm.

  As the ultraviolet curable resin, a known ultraviolet curable resin (including a polymerizable oligomer, a polyfunctional monomer, a monofunctional monomer, a photopolymerization initiator, an additive, and the like) can be used.

  Examples of such ultraviolet curable resins include urethane oligomers having a plurality of ethylenic double bonds (preferably acryloyl groups or methacryloyl groups), oligomers such as polyester oligomers and epoxy oligomers, pentaerythritol tetraacrylate (PETA), and pentaerythritol. It is preferably composed mainly of a polymerizable oligomer such as tetramethacrylate and dipentaerythritol hexaacrylate (DPEHA) and / or a polyfunctional monomer. The functional polymerization monomer used in the production of the modified silica fine particles can also be used as appropriate.

  The ultraviolet curable resin is generally composed of an oligomer, if necessary, a reactive diluent (polyfunctional monomer, monofunctional monomer), and a photopolymerization initiator as described above. Examples of photopolymerization initiators include benzoin, benzophenone, benzoyl methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, dibenzyl, 5-nitroacenaphthene, hexachlorocyclopentadiene, p-nitrodiphenyl, p-nitroaniline. 2,4,6-trinitroaniline, 1,2-benzanthraquinone, 3-methyl-1,3-diaza-1,9-benzanthrone; acetophenone, acetophenone benzyl ketal, anthraquinone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone compounds, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimene Xylbenzophenone, 4,4′-diaminobenzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, Carbazole, xanthone, 1,1-dimethoxydeoxybenzoin, 3,3′-dimethyl-4-methoxybenzophenone, thioxanthone compound, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 1- (4-dodecylphenyl)- 2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, triphenylamine, 2,4,6-trimethylbenzoyl Diphenylphosphine oxide, bis- (2,6-dimethyl) Toxibenzoyl) -2,4,4-trimethylpentylphosphine oxide, bisacylphosphine oxide, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, Fluorenone, fluorene, benzaldehyde, Michler's ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 3-methylacetophenone, 3,3 ′, 4,4′-tetra ( t-butylperoxycarbonyl) benzophenone (BTTB) and the like, and combinations of BTTB and dye sensitizers such as xanthene, thioxanthene, coumarin, ketocoumarin and the like. Of these, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one is preferred.

  These can be used alone or in combination of two or more. Each of the oligomer, reactive diluent and initiator may be used alone or in combination of two or more. As for content of a reactive diluent, 0.1-10 mass parts is common with respect to 100 mass parts of ultraviolet curable resin, and 0.5-5 mass parts is preferable. The content of the photopolymerization initiator is preferably 5 parts by mass or less with respect to 100 parts by mass of the ultraviolet curable resin.

  The ultraviolet curable resin may further contain a silicone polymer. Generally, it is a graft copolymer having silicone as a side chain, and preferably an acrylic graft copolymer having silicone as a side chain.

  In the present invention, various additives can be added as necessary to the above. Examples of these additives include antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, and anti-aging. Agent, thermal polymerization inhibitor, colorant, leveling agent, surfactant, storage stabilizer, plasticizer, lubricant, solvent, inorganic filler, organic filler, filler, wettability improver, coating surface improver, etc. Can be mentioned.

  The hard coat layer is composed mainly of the above components, but is excellent in various functions by further modification of the above oligomer or monomer, or further use of other functional resins and additives. A hard coat layer can be obtained.

  The antireflection film is formed by lamination on a transparent substrate, and various materials can be used as the material of the transparent substrate, such as polyethylene terephthalate (PET), triacetyl cellulose (TAC), Polyethylene naphthalate (PEN), acrylic resin, polycarbonate; polytetrafluoroethylene (PTFE), 4-fluoroethylene-perchloroalkoxy copolymer (PFA), 4-fluoroethylene-6-fluoropropylene copolymer (FEP), fluoroethylene resins such as 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF) Each film can be mentioned. A PET film and a TAC film are particularly preferable from the viewpoint of transparency and flexibility.

  The thickness of the transparent substrate layer is preferably about 6 to 250 μm.

  An intermediate layer having adhesiveness is laminated on the transparent base material layer.

  As the material for the intermediate layer, any material can be used without particular limitation as long as it has good light transmittance, can achieve a desired refractive index, and can be bonded with a predetermined thickness. Suitable examples include acrylic resins (including sulfur-modified acrylic resins), EVA (ethylene vinyl acetate copolymer), polyvinyl acetal resins (for example, polyvinyl formal, polyvinyl butyral (PVB resin), and modified PVB). And vinyl chloride resin. Particularly preferred are acrylic resins (especially sulfur-modified acrylic resins) and EVA.

  As said acrylic resin, the copolymer of (meth) acrylic acid ester, such as methyl methacrylate, butyl methacrylate, butyl acrylate, 2-hydroxyethyl acrylate, and comonomers, such as acrylic acid and methacrylic acid; or , By introducing a functional group such as a carboxyl group, a hydroxyl group, a methylol group, or a glycidyl group into the side chain of these copolymers, an aliphatic isocyanate such as tetramethylene diisocyanate or trimethylhexamethylene diisocyanate, or TDI (tolylene diisocyanate), An acrylic urethane resin obtained by crosslinking with an aromatic isocyanate such as MDI (diphenylmethane diisocyanate) or NDI (naphthalene diisocyanate) can be exemplified. A particularly preferable example is a sulfur atom as an acrylic resin monomer. By polymerization reaction using a monomer having a functional group having, or is obtained by reacting a compound having a sulfur atom in the functional group of the acrylic resin polymer, mention may be made of sulfur-modified acrylic resin.

  Moreover, a silane coupling agent can be added to EVA resin for the purpose of improving adhesive force. Known silane coupling agents for this purpose are, for example, γ-chloropropyltrimethoxysilane; vinyltrichlorosilane; vinyltriethoxysilane; vinyl-tris- (β-methoxyethoxy) silane; γ-methacryloxy. Propyltrimethoxysilane; β- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane; γ-glycidoxypropyltrimethoxysilane; vinyltriacetoxysilane; γ-mercaptopropyltrimethoxysilane; γ-aminopropyltrimethoxysilane N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane and the like can be mentioned. The compounding amount of these silane coupling agents is generally 5 parts by mass or less, preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the EVA resin.

  Furthermore, a crosslinking aid can be added to the EVA resin in order to improve the gel fraction of the EVA resin and improve the durability. As crosslinking aids used for this purpose, known tri-functional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate as well as monofunctional crosslinking aids such as NK ester (trade name) are known. Etc. can also be mentioned. Generally the compounding quantity of these crosslinking adjuvants is 10 mass parts or less with respect to 100 mass parts of EVA resin, Preferably it is 1-5 mass parts.

  Furthermore, hydroquinone; hydroquinone monomethyl ether; p-benzoquinone; methyl hydroquinone and the like can be added for the purpose of improving the stability of the EVA resin, and the blending amount thereof is generally 5 parts by mass with respect to 100 parts by mass of the EVA resin. It is as follows.

  In addition to the above, a colorant, an ultraviolet absorber, an anti-aging agent, a discoloration preventing agent and the like can be added as necessary. Examples of the colorant include inorganic pigments such as metal oxides and metal powders, and organic pigments such as azo-based, phthalocyanine-based, additive-based, acidic or basic dye-based lakes. Examples of ultraviolet absorbers include 2-hydroxy-4-octoxybenzophenone; benzophenones such as 2-hydroxy-4-methoxy-5-sulfobenzophenone; 2- (2′-hydroxy-5-methylphenyl) benzotriazole Benzotriazoles; phenyl salsylates; hindered amines such as pt-butylphenyl salsylates. Antiaging agents include amines; phenols; bisphenyls; hindered amines, such as di-t-butyl-p-cresol; bis (2,2,6,6-tetramethyl-4-piperazyl). ) Sebacate.

  The refractive index of the intermediate layer can be various refractive indexes depending on the relationship between the refractive index of the transparent base material and the hard coat layer, but can be set to about the middle of the refractive index of the transparent base material and the hard coat layer. It is excellent, generally in the range of 1.53 to 1.63, preferably in the range of 1.54 to 1.62, particularly preferably in the range of 1.55 to 1.61. The thickness of the intermediate layer can be set to various thicknesses by setting the refractive index, but is generally in the range of 60 to 115 nm, preferably in the range of 63 to 109 nm, particularly in the range of 65 to 103 nm. By setting the values within these ranges, it is possible to realize an interference fringe prevention function in addition to the antireflection function. In particular, when PET (refractive index: 1.65) or a material having a refractive index close thereto is used as the transparent substrate, an excellent interference fringe prevention function can be realized by setting the above range.

  A low refractive index layer is laminated on the hard coat layer.

  The low refractive index layer can be formed of, for example, a fluorine or non-fluorine low refractive index organic thin film.

  Examples of the non-fluorine organic thin film include acrylic resins, silicon resins, acrylic silicon resins, urethane resins and the like used for hard coats.

  Fluorine organic thin films include FET (fluoroethylene / propylene copolymer), PTFE (polytetrafluoroethylene), ETFE (ethylene / tetrafluoroethylene), PVF (polyvinyl fluoride), PVD (polyvinylidene fluoride), etc. Can be mentioned.

  Further, in order to impart antifouling properties, easy slipping, etc., fluorine-based and silicon-based additives may be added. Among these, a silicon resin or an acrylic resin is preferable because it is inexpensive.

  The low refractive index layer may be a layer made of a cured film of a thermosetting resin or an ultraviolet curable resin used for a hard coat layer, and an ultraviolet curable resin is particularly suitable in terms of hardness and handling. is there.

  Since such an organic thin film is generally a low refractive index thin film, it is suitable in the present invention.

In addition, the antistatic fillers composed of antimony oxide (Sb ₂ O ₅ ) fine particles having a pyrochlore structure according to the present invention are commonly used ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide), tin oxide. Compared with an antistatic filler made of conductive metal oxide fine particles and the like, the refractive index is low. Therefore, the refractive index of the hard coat layer containing the antistatic filler can be made relatively low. However, when the refractive index of the hard coat layer is made low by making use of this, the antireflection film In order to sufficiently exhibit the antireflection effect, it is necessary to further lower the refractive index of the low refractive index layer, and it is preferable to set the refractive index to 1.48 or less, for example.

  In order to improve the antireflection performance in this way, as a method for obtaining a low refractive index layer having a low refractive index, there is a method for reducing the refractive index by filling a filler such as hollow silica (porous silica). In particular, since hollow silica is an inorganic compound filler, a decrease in refractive index due to this is preferable in that a harder low-refractive-index thin film can be formed as compared to a decrease in refractive index due to an organic additive. It is particularly preferable when it is arranged.

  Since the hollow silica is hollow and contains air inside, it has a very low refractive index (about 1.34 to 1.44) compared to ordinary silica (refractive index: about 1.46). This can be created by covering the surface of porous silica fine particles with an organosilicon compound or the like and closing the pore entrance. The average particle diameter of the hollow silica can generally be in the range of 1 nm to 1 μm, preferably 5 to 200 nm, and particularly preferably 10 to 100 nm. From the viewpoint of the size of the contribution to lowering the refractive index, the larger the particle size, the better. However, if the particle diameter exceeds about 1 μm, the transparency is extremely lowered and the contribution of diffuse reflection becomes large, and it looks whitish. . From the viewpoint of transparency, the smaller the particle size, the better. However, in addition to the above-mentioned contribution to lowering the refractive index, hollow silica fine particles tend to aggregate, especially when the particle size is smaller than about 0.5 nm. Uniform dispersion is not easy.

  The thickness of the low refractive index layer is preferably an optical film thickness within a range where the antifouling function can be obtained in order to achieve both the antireflection function and the antifouling function, For example, it is preferable to set it to about ¼λ (= 125 nm) of light having a wavelength of 500 nm.

  By forming such an organic thin film on the hard coat layer as a low refractive index layer as the outermost surface layer of the antireflection film, an antireflection function can be obtained, and further excellent antifouling properties and scratch resistance can be obtained. Can also be obtained.

  A further preferred embodiment of the present invention will be described with reference to FIG.

  As described above, in FIG. 1, the antistatic filler of the present invention is dispersed on the transparent base layer 14 while having an intermediate layer 13 having adhesiveness, a certain hardness and a required thickness. An antireflection film is shown in which a hard coat layer 12 imparted with an antistatic property by containing a formed resin and a low refractive index layer 11 having a lower refractive index than the hard coat layer are sequentially laminated. . In such a configuration, an antireflection film that is particularly superior in terms of interference fringe performance can be obtained by further performing the following for each refractive index and the like.

That is, in the configuration of FIG. 1, the following expressions (1) to (4):
n ₁ > n ₂ > n ₃ (1)
| N ₂ − (n ₁ + n ₃ ) /2|≦0.07 (2)
1.56 ≦ n ₁ ≦ 1.71 (3)
1.50 ≦ n ₂ ≦ 1.70 (4)
(Where n ₁ is the refractive index of the transparent substrate, n ₂ is the refractive index of the intermediate layer, and n ₃ is the refractive index of the hard coat layer)
And the thickness d (nm) of the intermediate layer is in the range of 65 to 103 nm.

  The range of 65 to 103 nm, which is the range of the thickness d (nm) of the intermediate layer, is preferably in the range of 65 to 77 nm, 78 to 93 nm, or 88 to 103 nm. These three ranges are the three light peak wavelength regions corresponding to the RGB regions included in the three-wavelength fluorescent lamp considered in the present invention (for example, three wavelengths near 450 nm, 545 nm, and 610 nm). With such a thickness d (nm), the light reflected at each specific peak wavelength can be canceled out. Therefore, in the overall design of the reflective film and the front filter for display, it is possible to dramatically reduce interference fringes corresponding to each specific peak wavelength that becomes an obstacle.

The thickness d (nm) of this intermediate layer is expressed by the following formula (5):
d = λ / (4 × n ₂ ) (5)
(Where λ is the wavelength (nm) of the light targeted for interference fringe reduction)
The range corresponds to the value obtained by. That is, the three ranges forming the range of the thickness d (nm) of the intermediate layer of the present invention are the three-wavelength type considered in the present invention as the wavelength λ (nm) of the light of the above formula (5). It can be obtained by selecting and applying values corresponding to the three peak wavelength regions of RGB corresponding to the RGB regions of the fluorescent lamp, that is, the three wavelength regions near 450 nm, 545 nm, and 610 nm. It is a range. The values of the peak wavelengths of the three lights corresponding to the RGB regions included in the three-wavelength fluorescent lamp are slightly different depending on the design of the respective fluorescent lamps. Of course, it is also possible to apply to the above. It is naturally possible to apply a value intentionally shifted from the true center value of the peak wavelength to the above equation (5).

  The thickness d (nm) of the intermediate layer can be set to a value in the range of 65 to 103 nm. From the range of 65 to 77 nm, the range of 78 to 93 nm, and the range of 88 to 103 nm, Furthermore, it is possible to set the value within a selected range as follows.

  The range of 65 to 77 nm of the thickness d (nm) of the intermediate layer is preferably in the range of 68 to 75 nm, particularly preferably in the range of 70 to 73 nm, so that the specific peak wavelength centered at 450 nm is It is possible to effectively suppress the occurrence of interference fringes.

  The range of 78 to 93 nm of the thickness d (nm) of the intermediate layer is preferably in the range of 83 to 91 nm, particularly preferably in the range of 85 to 89 nm, with respect to a specific peak wavelength centered at 545 nm. It is possible to effectively suppress the occurrence of interference fringes.

  The range of 88 to 103 nm of the thickness d (nm) of the intermediate layer is preferably in the range of 92 to 101 nm, particularly preferably in the range of 94 to 99 nm, so that the specific peak wavelength centered at 610 nm is It is possible to effectively suppress the occurrence of interference fringes.

The refractive index n ₂ of the intermediate layer is generally in the range of 1.50 to 1.70, preferably in the range of 1.54 to 1.65, particularly preferably in the range of 1.55 to 1.62. By selecting such a range and combining it with the thickness of the intermediate layer, the interference fringe reduction effect of the present invention can be exhibited.

The value of the refractive index n ₂ of the intermediate layer is expressed by the following formula:
| N ₂ − (n ₁ + n ₃ ) / 2 |
In general, it is preferable that the value obtained by the above is 0.07 or less, preferably 0.05 or less, particularly 0.03 or less. By setting the value of the refractive index n ₂ of the intermediate layer according to this standard and reducing the difference in the refractive index of each layer, an antireflection film with particularly enhanced interference fringe generation suppression effect and antireflection effect can be obtained. .

  The following examples further illustrate the present invention. The present invention is not limited by the following examples.

[Example]
Production of antireflection film and display filter of the present invention Immediately after the formation of a PET film (refractive index: 1.65, 150 μm thickness) as a transparent substrate, a sulfur-modified acrylic resin was cast on this PET film. Were rolled and bonded to form an intermediate layer (intermediate refractive index layer) having a refractive index of 1.59 and a thickness of 80 nm. Next, 75 parts by mass of dipentaerythritol hexaacrylate (DPHA) (manufactured by Nippon Kayaku Co., Ltd., trade name DPHA) as a polyfunctional acrylate monomer, 25 parts by mass of Sb ₂ O ₅ having a mean particle size of 150 nm and a picropore structure A coating solution containing 100 parts by mass of MEK, 100 parts by mass of toluene, and 4 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name Irgacure 184) as a polymerization initiator is prepared, and further above the intermediate layer described above. It was applied to. Next, after drying at 80 ° C. for about 1 minute, it was cured by ultraviolet irradiation (light quantity 200 mJ / cm ² ) to form a hard coat layer (refractive index 1.54, thickness 5 μm).

Furthermore, 2 parts by mass of DPHA, 2 parts by mass of porous silica (hollow silica) (average particle size 100 nm), 1 part by mass of a photopolymerization initiator (trade name Irgacure 184, manufactured by Ciba Specialty Chemicals) as a polymerization initiator, solvent A coating solution containing 95 parts by mass of MEK was prepared and applied on the hard coat layer described above. Next, after drying at 80 ° C. for about 1 minute, the film was cured by ultraviolet irradiation (light quantity 200 mJ / cm ² ) to form a low refractive index layer (refractive index 1.44, thickness 90 nm).

  Furthermore, this was bonded together to the glass plate of thickness 2.5mm, and the filter for displays was created.

[Comparative example]
Manufacture of antireflection film and display filter using ATO Instead of using Sb ₂ O ₅ having a picroa structure for the hard coat layer, 50 parts by mass of ATO (antimony-doped tin) having an average particle diameter of 150 nm was used. Except for this, an antireflection film and a display filter were produced in the same manner as in the Examples.

  Except for the hard coat layer having a refractive index of 1.60 and a thickness of 5 μm, the refractive index and thickness of each layer are the same as in the examples.

[Measurement of transmittance]
The average transmittance in the vicinity of a wavelength of 400 to 800 nm was measured using a Hitachi visible ultraviolet light spectrometer (U-4000).

[Measurement of surface resistance]
The surface resistance value was measured based on JISK6911 by applying 500 V using a digital ultrahigh resistance meter (R8340A) manufactured by Advantest.

[Evaluation of interference fringe generation]
The display filter of the example and the comparative example is used in a room where a three-wavelength fluorescent lamp (product name: FHF32EX-N, manufactured by Toshiba) is used as a ceiling lamp, so that the antireflection film surface is on the indoor side with a smooth wall surface. Installed. The degree of interference fringes (oil stain) generated by illumination of a three-wavelength fluorescent lamp was visually evaluated. The evaluation was performed in three stages: ○: conspicuous interference fringes are hardly visible Δ: conspicuous interference fringes are slightly visible ×: conspicuous interference fringes are clearly visible The results are shown in the following table.

ハードコート層 透過率 表面抵抗 干渉縞
フィラー 屈折率 （Ω／□） 評価

実施例 Ｓｂ₂Ｏ₅ １．５４ ９２％ 1.0×10¹⁰ ○

比較例 ＡＴＯ １．６０ ８０％ 1.0×10¹⁰ ×

[result]

table

Hard coat layer Transmittance Surface resistance Interference fringes
Filler Refractive index (Ω / □) Evaluation

Example Sb ₂ O ₅ 1.54 92% 1.0 × 10 ¹⁰ ○

Comparative Example ATO 1.60 80% 1.0 × 10 ¹⁰ ×

In the case of having the same level of surface resistance, the filter for display using an antireflection film having an antistatic hard coat layer in which Sb ₂ O ₅ having a pyrochlore structure is dispersed is antistatic in which ATO is dispersed. Compared with the filter for display by the antireflection film which has a hard-coat layer of this, while showing the high light transmittance, the conspicuous interference fringe was not visually recognized. In addition, it was excellent in color reproducibility without causing a bias in the transmitted color.

Moreover, the display filter using an antireflection film having an antistatic hard coat layer in which Sb ₂ O ₅ having a pyrochlore structure is dispersed is also excellent in antireflection properties, is difficult to adhere dust, and the front surface is hardly damaged. It was a thing.

  That is, the display filter using an antireflection film using the antistatic filler of the present invention has an antistatic property imparted to the hard coat layer and has an advantageous structure for manufacturing, while having an antireflection property, light transmittance, and color reproduction. It has excellent properties, interference fringe reduction, dust adhesion prevention, scratch prevention, and the like.

FIG. 1 is a cross-sectional view of an example of the basic structure of the antireflection film of the present invention. FIG. 2 is a cross-sectional view showing the structure of a typical front filter for PDP. FIG. 3 is a cross-sectional view showing an example of a general structure of an antireflection film manufactured by a wet coating method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Low refractive index layer 12 Hard coat layer 13 Intermediate layer 14 Transparent base material layer 20 Light emission panel 21 Antireflection layer 22 Electromagnetic wave shield layer 23 Transparent substrate 24 Color tone correction filter layer 25 Near-infrared cut layer 31 Low refractive index layer 32 Hard coat property High refractive index layer having 33 transparent substrate

Claims (20)

  An antistatic filler comprising conductive fine particles having proton conductivity.   The antistatic filler according to claim 1, wherein the conductive fine particles are fine particles of antimony oxide having a pyrochlore structure.   The antistatic filler according to claim 2, wherein the fine particles have an average particle size in the range of 5 to 300 nm.   The hard-coat layer containing the antistatic filler in any one of Claims 1-3 disperse | distributed in resin and this resin.   The hard-coat layer of Claim 4 which contains the said antistatic filler in the ratio of the range of 4-85 mass% with respect to the total mass of a hard-coat layer.   The hard coat layer according to claim 4 or 5, wherein the thickness of the hard coat layer is in the range of 1 to 10 µm.   The hard coat layer according to claim 4, wherein the resin is an ultraviolet curable resin.   The antireflection film containing the hard-coat layer in any one of Claims 4-7. An antireflection film in which a low refractive index layer having a refractive index smaller than that of an intermediate layer, a hard coat layer, and a hard coat layer is sequentially laminated on a transparent substrate,
The antireflection film, wherein the hard coat layer is the hard coat layer according to any one of claims 4 to 7.   The antireflection film according to claim 9, wherein the transparent substrate is a PET film.   The antireflection film according to claim 9 or 10, wherein the refractive index of the intermediate layer is in the range of 1.53 to 1.63.   The thickness of the said intermediate | middle layer exists in the range of 60-115 nm, The antireflection film in any one of Claims 9-11.   The antireflection film according to any one of claims 9 to 12, wherein the low refractive index layer contains a resin in which hollow silica is dispersed.   The antistatic layer containing resin and the antistatic filler in any one of Claims 1-3 disperse | distributed in this resin.   The antistatic layer according to claim 14, comprising the antistatic filler in a proportion in the range of 4 to 85 mass% with respect to the total mass of the antistatic layer.   The antistatic layer according to claim 14 or 15, wherein the antistatic layer has a thickness in the range of 1 to 10 µm.   The antistatic layer according to claim 14, wherein the resin contains an ultraviolet curable resin.   The antireflection film containing the antistatic layer in any one of Claims 14-17.   A display filter comprising the antireflection film according to claim 8. The display filter according to claim 19, wherein the antireflection film is provided as an outermost layer.

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