JP5758672B2 - Antireflection sheet, method for producing the same, and touch panel and display using the antireflection sheet - Google Patents

Description

  The present invention relates to a light reflection preventing sheet with improved adhesion of an antireflection film provided on a base sheet made of an ionizing radiation curable acrylic resin, a manufacturing method thereof, and a touch panel and a display using the light reflection preventing sheet.

  In recent years, various displays such as a liquid crystal display (LCD), a plasma display panel (PDP), a cathode ray tube (CRT), an organic light emitting display (OLED), and electronic paper have been developed. In addition to television, these are also used as mobile phones, personal digital assistants (PDAs), notebook computers, OA / medical devices, POS registers, ticket machines, car navigation systems, FA devices, digital signage, etc. Widely used regardless of organization, school, hospital, etc. In addition, touch panels arranged as input means on the surfaces of various displays are widely used.

  An antireflection sheet is provided on the outermost surface of the display or touch panel as a means for preventing external light such as sunlight or indoor lighting from being reflected and degrading the image display performance. By using such a light reflection preventing sheet, the reflectance of external light (total light reflectance) can be reduced by about 3 to 4%. It can be said that the light reflection preventing sheet is an essential function for improving the visibility of the display.

In the antireflection sheet, an antireflection film in which transparent inorganic oxides having different refractive indexes (such as SiO ₂ and TiO ₂ ) are alternately laminated is usually formed on one main surface of a base sheet made of resin. And the adhesion layer or the contact bonding layer is formed in the other main surface of a base sheet, and the whole surface is bonded and used for the outermost surface of a display or a touch panel.

  The base sheet is required to be transparent, and a transparent film material such as a cyclic olefin resin such as polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), norbornene or the like is used. Usually, in order to ensure the surface hardness of the base sheet, a hard coat layer made of an ultraviolet curable acrylic resin or a thermosetting silicone resin is formed on the surface of the transparent film material by dip coating or roll coating, An antireflection film is formed on the hard coat layer.

JP 2004-85643 A Japanese Patent No. 3366864

  The light reflection preventing sheet may be exposed to a severe temperature / humidity change or high intensity light irradiation depending on the use situation or use environment together with the touch panel or the display to which the light reflection preventing sheet is applied. In particular, in outdoor applications and applications such as vending machines installed in cars, POS systems for gas stations, navigation systems, etc., they are easily affected by sunlight irradiation, high temperature / humidity environment, etc. over a long period of time. In addition, even when used in factories or public facilities, there are cases where light of a specific wavelength is continuously received by various illumination light sources such as mercury lamps.

  In the environment as described above, since the base sheet causes a deterioration reaction due to ultraviolet light or light on the short wavelength side of visible light (wavelength of 300 to 550 nm), when the light reflection preventing sheet is used in such a light irradiation environment, the comparison is made. The antireflection film peels off from the base sheet within a short period of time.

  Further, when the light reflection preventing sheet is exposed to the atmosphere of a high temperature / humidity environment, oxygen and water vapor in the atmosphere enter and diffuse near the interface between the reflection preventing film and the base sheet. This oxygen or water vapor promotes a reaction (oxidation reaction or hydrolysis) that degrades (lower molecular weight) the base sheet in the extreme surface area (depth area of about 10 nm or less from the surface) of the base sheet in contact with the antireflection film. In other words, the antireflection film cannot withstand the stress exerted on the base sheet, and the base sheet may peel off from the antireflection film within a relatively short period of time.

Such a problem of peeling due to stress is currently a problem that is difficult to avoid in forming an antireflection film. For example, when considering the case where an antireflection film is formed by laminating a number of lamination units composed of a low refractive index layer (such as SiO ₂ ) and a high refractive index layer (such as TiO ₂ ), the interface of each layer is proportional to the film thickness The stress acting on the surface also increases. For this reason, the adhesiveness between the base sheet and the antireflection film is always easily lowered, and peeling is likely to occur. Such a problem of peeling off of the antireflection film is a problem to be solved by all means in order to continue to use the antireflection sheet satisfactorily.

  The present invention has been made in view of the above problems, and is a light antireflection sheet that can be expected to exhibit stable antireflection performance over a long period of time by preventing a decrease in adhesion between the antireflection film and the base sheet. And it aims at provision of the touch panel and display using the said sheet | seat. Therefore, this light reflection preventing sheet can be suitably used in harsh environments including outdoors.

In order to solve the above problems, an antireflection sheet of the present invention includes a base sheet made of an ionizing radiation curable acrylic resin, an intermediate layer provided on the base sheet, and a transparent provided on the intermediate layer. An inorganic oxide layer, and the intermediate layer is formed by sequentially laminating an acrylic resin-silica hybrid layer and an ionizing radiation curable organic-inorganic composite resin layer from the base sheet side, and the acrylic resin-silica hybrid The layer is characterized in that the raw material comprises a silica precursor .

  Since the base sheet made of the ionizing radiation curable acrylic resin has a high hardness, a separate hard coat is not required, and the layer structure is reduced. As a result, the interfaces that may be peeled can be reduced. Further, since the base sheet is a chemically stable material, it can maintain a stable form even in a severe light irradiation environment or a high-temperature and high-humidity environment, so that peeling due to deterioration of the base material hardly occurs.

  Moreover, by providing the intermediate layer consisting of the above two layers between the base sheet and the transparent inorganic oxide layer, adhesion with the base sheet made of ionizing radiation curable acrylic resin is ensured by the acrylic resin-silica hybrid layer, Moreover, the adhesiveness between the base sheet and the transparent inorganic oxide layer is improved by ensuring the adhesiveness with the transparent inorganic oxide layer by the ionizing radiation curable organic-inorganic composite resin layer.

  The ionizing radiation curable organic-inorganic composite resin layer of the light reflection preventing sheet comprises both an organic component and an inorganic oxide, and at least in a region within a depth of 10 nm from the surface in contact with the transparent inorganic oxide layer, The ratio B / A of the number B of inorganic elements in the inorganic oxide to the number A of organic elements in the organic component of the layer is in the range of 0.05 to 0.35 in terms of the element number ratio.

  With this configuration, there are many inorganic oxides in the ionizing radiation curable organic-inorganic composite resin layer in the region near the surface where the ionizing radiation curable organic-inorganic composite resin layer is in contact with the transparent inorganic oxide layer. It becomes a structure, it is aimed so that a mutual component may be similar, and both affinity is improved significantly. Therefore, the adhesion between the ionizing radiation curable organic-inorganic composite resin layer and the transparent inorganic oxide layer is remarkably improved as compared with the conventional case, and peeling does not easily occur.

  When the ratio B / A in the previous period is less than 0.05, sufficient adhesion with the transparent inorganic oxide layer cannot be obtained. On the other hand, when the ratio B / A is larger than 0.35, the surface of the organic-inorganic composite resin layer has too many inorganic oxides, so that cracks are easily generated on the surface.

  Here, the inorganic oxide component contained in the organic-inorganic composite resin layer contains at least one element of Si, Ti, Zr, Sn, Sb, and Al, and the ratio B / A is an organic / inorganic ratio. The element number ratio (Si + Ti + Zr + Sn + Sb + Al) / C of the sum of the elements constituting the inorganic oxide component contained in the composite resin layer and the carbon of the organic component, wherein the ratio B / A is the organic-inorganic composite In the resin layer, it may be set so as to be constant or gradually decreased from the surface toward the depth direction.

  By this structure, in the area | region of the surface vicinity which contacts the transparent inorganic oxide layer of the said organic inorganic composite resin layer, it becomes the structure where many inorganic oxides exist, and the area | region of the surface vicinity which contacts an acrylic resin-silica hybrid layer In the structure, there are many organic components. Thereby, each component is similar to each other, so that the affinity between the upper and lower layers of the organic-inorganic composite resin layer is remarkably improved.

The organic-inorganic composite resin layer has an average primary particle size of 5 to 40 nm and is composed of at least one of SiO ₂ , TiO ₂ , ZrO ₂ , SnO ₂ , ATO, and Al ₂ O _3. The inorganic oxide fine particles may be dispersed in the range of 20 wt% to 90 wt%. By adjusting in this way, the ratio B / A can be in the range of 0.05 to 0.35 in terms of the number ratio of elements.

  As a method for adjusting the ratio B / A of the inorganic oxide to the organic component in a region 10 nm deep from the surface of the transparent inorganic oxide layer to 0.05 to 0.35, for example, (1) Patent Document 2 (2) A method of forming a very thin layer of a semiconductor or metal such as Si described in (2) A method of contacting a gas phase with a surface using a silane coupling agent (surface modification with a silane coupling agent), (3) A method in which a silicone component (reactive or non-reactive with respect to ultraviolet rays or heat) is mixed is also possible. However, in the methods exemplified in (1) to (3), the effect of the present invention cannot be obtained at all, and the light resistance may be lowered.

  The reason why the effect of the present invention is obtained is that, in the present invention, the organic-inorganic composite resin layer and the inorganic oxide dispersed in this layer are physically bonded by a so-called anchoring effect or the like. For this reason, this point is decisively different from (1) to (3) exemplified.

  In the present invention, the inorganic oxide on the surface of the organic-inorganic composite resin layer in the vicinity of the surface in contact with the transparent inorganic oxide layer is originally rich, and is not easily affected by the photo-oxidative degradation of the organic polymer. However, even if the organic polymer is deteriorated, it is considered that the transparent inorganic oxide layer is hardly peeled off due to the anchor action.

 The organic-inorganic composite resin layer of the light reflection preventing sheet has a thickness of 3000 nm to 9000 nm. If it is less than 3000 nm, the influence of oxygen inhibition that cannot be avoided in the surface region is received in the entire thickness region, and as a result, the polymerization reaction does not proceed and the curing is poor. On the other hand, if it is thicker than 9000 nm, the elasticity is reduced, so that cracks tend to occur on the surface.

  The acrylic resin-silica hybrid layer of the light reflection preventing sheet is characterized in that the raw material contains a silica precursor.

  Since the acrylic resin-silica hybrid layer provides flexibility, the stress exerted on the base sheet side by the antireflection film and the organic-inorganic composite resin layer is reduced. Therefore, even if the base sheet is invaded by oxygen or water vapor in the atmosphere and deteriorates due to ultraviolet irradiation or the like, the adhesion between the antireflection film and the organic-inorganic composite resin layer and the base sheet is good. To be kept.

  The transparent inorganic oxide layer has a multilayer structure in which at least two kinds of different layers are laminated. Thereby, the reflectance of visible light (for example, visible light having a wavelength near 550 nm) that is easily perceivable by humans can be effectively reduced, and the characteristics as a light reflection preventing sheet can be improved.

  Furthermore, the transparent inorganic oxide layer is formed by laminating a second layer having a second refractive index different from the first refractive index and a first layer having the first refractive index in the same order, It is also possible to repeat the stacking unit of the first layer two or more. By repeatedly laminating as described above, higher antireflection properties can be imparted.

  Moreover, the light reflection prevention sheet of this invention can be made into the display or touch panel which was bonded or adhere | attached on the outermost surface. By providing the light reflection preventing sheet of the present invention on the outermost surface of a display or touch panel, a stable reflection preventing function can be exhibited over a long period of time even when used in harsh environments.

The method for producing an antireflection sheet of the present invention includes a paste application step of forming a paste layer by applying a precursor paste of an ionizing radiation curable acrylic resin to the surface of a first film base that is continuously drawn out; A wet laminating step of laminating a second film substrate on the paste layer, and an ionizing radiation curable acrylic resin film by curing the paste layer by irradiating the paste layer with ionizing radiation after the laminating step A resin curing step to form a base sheet by peeling the first and second film substrates from the ionizing radiation curable acrylic resin film after the resin curing step, and silica on the base sheet acrylic resins containing a precursor - that is applied to cure the silica hybrid A resin curing step for forming a first intermediate layer, a resin curing step for forming a second intermediate layer by applying and curing an ionizing radiation curable organic-inorganic composite resin, and transparent on the intermediate layer And a thin film forming step of forming an inorganic oxide layer.

  Such a base sheet made of an ionizing radiation curable acrylic resin has an advantage that it can be efficiently manufactured by forming a continuous sheet by casting and curing it by irradiation with ionizing radiation. Furthermore, by performing roll-to-roll processing in this way, thin film formation by sputtering, vapor deposition, etc., and thin film formation by wet coating, etc. can be continuously performed on the surface of the base sheet after ionizing radiation curing. Thus, there is an advantage that the manufacturing efficiency of the light reflection preventing sheet is remarkably improved.

  According to the present invention, it is possible to prevent a decrease in the adhesion between the antireflection film and the base sheet, and to provide a light reflection preventing sheet that can be expected to exhibit stable antireflection performance over a long period of time even under harsh environments including outdoors. The manufacturing method and a touch panel and a display using the sheet can be provided.

FIG. 1 is a schematic cross-sectional view showing a light reflection preventing sheet according to an embodiment of the present invention. FIG. 2 is a schematic view showing a method for manufacturing a base sheet of an antireflection sheet according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration example of a display device using the light reflection preventing sheet according to the embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a configuration example of a configuration of a resistive touch panel using the light reflection preventing sheet according to the embodiment of the present invention and an LCD combined therewith.

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

<Embodiment 1> (Light reflection preventing sheet)
FIG. 1 is a schematic cross-sectional view showing a light reflection preventing sheet 21 according to an embodiment of the present invention.

  The base sheet 1 is made of an ionizing radiation curable acrylic resin. Ionizing radiation includes ultraviolet rays and electron beams. Since the base sheet 1 made of the ionizing radiation curable acrylic resin has high hardness, a separate hard coat is not required, and the layer structure is reduced. As a result, the interfaces that may be peeled can be reduced. In addition, since the base sheet 1 is a chemically stable material, it can maintain a stable form even in a severe light irradiation environment or a high temperature and high humidity environment, and therefore, peeling due to deterioration of the base material hardly occurs.

  When the ionizing radiation curable acrylic resin is used as a starting material, the base sheet 1 can form a resin sheet having a very high hardness (for example, 3H to 9H in pencil hardness).

A preferred base sheet 1 will be described below. For ionizing radiation curable acrylic resin materials and polymerization initiators, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), isobutyl alcohol (IBA), ethyl alcohol, methyl alcohol, normal butyl alcohol (NBA), cyclohexanone (CAN), A paint (volatile solution) is prepared by adding a solvent such as diacetylacetone (DAA), butyl acetate, ethyl acetate, or isopropyl alcohol (IPA). Further, a nano-oxide particle material containing an inorganic oxide component such as SiO ₂ , ZrO ₂ , SnO ₂ may be added. As these particulate materials, various commercially available products that are uniformly dispersed in powder or an organic solvent can be used.

  However, it may be preferable not to use an organic solvent for the base sheet 1 for manufacturing reasons. In that case, the monomer described below can be used as a reactive diluent instead of the organic solvent.

  In the ionizing radiation curable acrylic resin material, the hardness and rollability (easy to break) of the base sheet after photocuring are determined by the monomers and oligomers in the molecular structure. Therefore, selection of an ionizing radiation curable acrylic resin material is important. Specifically, a monomer or oligomer component containing a vinyl group in the skeleton is used. Among them, the monomer is also called a reactive diluent, and an acrylic monomer, for example, trimethylolpropane triacrylate (TMPT) or its EO-modified, PO-modified product, pentaerythritol triacrylate (PET-3A) as a trifunctional monomer, 4 Examples of the functional monomer include pentaerythritol tetraacrylate, and examples of the hexafunctional monomer include dipentaerythritol hexaacrylate (DPE-6A). On the other hand, as the oligomer, a urethane-based or epoxy-based oligomer component containing a vinyl group is appropriately selected and introduced.

  About introduction | transduction of these monomer components and oligomer components, in order to make flexibility and hardness compatible, it is preferable to obtain | require optimal amount beforehand. In general, when the ratio of the oligomer component is high (including the case where the monomer component is zero), roll-to-roll molding becomes easier as the flexibility increases, but the hardness decreases. On the contrary, if the ratio of the oligomer component is reduced (including the case where the oligomer component is zero), the flexibility can be reduced but the hardness can be increased.

  Examples of the polymerization initiator for the monomer component and oligomer component include Irgacure 907 (2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one) manufactured by Ciba Specialty Chemicals Co., Ltd. A general photopolymerization initiator such as Irgacure 184 may be used.

  A sheet molding (base sheet 1) is obtained by performing a known casting method and ionizing radiation irradiation step using the paint. Here, the radical initiator contained in the coating material generates radicals by irradiation with ionizing radiation, and a crosslinking reaction (polymerization reaction) proceeds three-dimensionally with the generated radicals as starting points. Thereby, since the base sheet 1 has a three-dimensional network polymer structure, it has excellent mechanical strength (hardness, scratch resistance, etc.), and there is an advantage that a separate hard coat treatment is unnecessary.

  In order to impart both high hardness and heat resistance to the base sheet 1, a siloxane skeleton can be introduced into the molecular chain, or silica fine particles (so-called nano silica) having a particle size of 100 nm or less can be dispersed. In this case, the siloxane skeleton includes a method in which an acrylic monomer and siloxane are addition-polymerized (hybridization) using a sol-gel method. As this specific method, for example, “the latest technology of plastic hard coat material” (CMC Publishing Co., Ltd., 2008) can be referred to.

  Further, the surface of the base sheet 1 may be subjected to a surface treatment such as shape shaping (embossing shaping) by pressing a carrier having a predetermined surface roughness.

  The base sheet 1 is created by the method shown in FIG. 2, for example. Specifically, first, a paste layer 12 is formed by applying a coating paste 11 made of a precursor of an ionizing radiation curable acrylic resin to the surface of the first film substrate 10 that is continuously drawn out (paste application). Step), and the second film substrate 13 is laminated on the paste layer 12 (wet laminating step). Thereafter, the paste layer 12 is irradiated with ionizing radiation 14 to cure the paste layer 12, thereby forming an ionizing radiation curable acrylic resin film 15 (resin forming step). Finally, the first film substrate 10 and the second film substrate 13 are peeled to obtain an ionizing radiation curable acrylic resin film 15 (peeling step).

  The base sheet 1 made of such an ionizing radiation curable acrylic resin has an advantage that it can be efficiently manufactured by forming a continuous sheet by casting and curing by irradiation with ionizing radiation. Furthermore, by performing roll-to-roll processing in this way, thin film formation by sputtering, vapor deposition, etc., or thin film formation by wet coating, etc. can be continuously performed on the surface of the base sheet 1 after ionizing radiation curing. It becomes possible, and there is an advantage that the manufacturing efficiency of the light reflection preventing sheet 21 is remarkably improved.

  The intermediate layer 8 is configured by laminating an acrylic resin-silica hybrid layer 2 and an ionizing radiation curable organic-inorganic composite resin layer 3 from the base sheet 1 side.

  The acrylic resin-silica hybrid layer 2 is made of a material containing a silica component in an acrylic resin. As a preferable material, a material containing a poly (meth) acrylate resin and a silica precursor (for example, “Composeran AC601” manufactured by Arakawa Chemical Industries, Ltd.) is exemplified.

  As said acrylic resin, the resin component with which the monomer and oligomer containing a general acrylic group were blended can be selected. Moreover, although silicon alkoxide etc. can be used as said silica precursor, in order to express flexibility, a thing with a low number of acrylic acid groups and a number of alkoxyl groups is respectively preferable. The acrylic resin-silica hybrid layer 2 is formed by performing corona treatment on the base sheet 1 and applying the above-mentioned material, followed by curing by irradiation with heat or ultraviolet rays.

  Since flexibility is imparted by the acrylic resin-silica hybrid layer 2, the stress exerted on the base sheet 1 side by the transparent inorganic oxide layer 4 and the organic-inorganic composite resin layer 3 is reduced. Therefore, even if the base sheet 1 is invaded by oxygen or water vapor in the atmosphere and deteriorated by receiving ultraviolet irradiation or the like, the transparent inorganic oxide layer 4 and the organic-inorganic composite resin layer 3 and the base sheet 1 The adhesion of is kept good.

  Preferable materials for the ionizing radiation curable organic-inorganic composite resin layer 3 include “Z7524” manufactured by JSR Corporation, “U1006” manufactured by Chisso Corporation, and the like. In particular, the materials described in Patent Document WO2008 / 069217 Are preferably used.

  The thickness of the organic-inorganic composite resin layer 3 is preferably in the range of 1 μm to 10 μm. As a material, an organic component such as an ionizing radiation curable acrylic resin or urethane resin is a main component, and an inorganic oxide (an oxide containing at least one element of Si, Ti, Zr, Sn, Sb, and Al) Comprising.

  The organic-inorganic composite resin layer 3 is set so that the ratio of the inorganic oxide is higher to a predetermined value in the surface in contact with the transparent inorganic oxide layer 4 and in the vicinity thereof than in other regions. The “neighboring region” here refers to a region at least 10 nm in depth from the surface. However, the ratio of the inorganic oxide over a deeper region may be higher than that in other regions.

  Specifically, in the organic-inorganic composite resin layer 3, the inorganic in the inorganic oxide with respect to the number A of organic elements in the organic component (here, the carbon component) in the surface in contact with the transparent inorganic oxide layer 4 and in the vicinity thereof. The ratio B / A (that is, (Si + Ti + Zr + Sn + Sb + Al) / C) of the number of elements B (here, the sum of the number of elements of Si, Ti, Zr, Sn, Sb, Al) is 0.05 or more and 0.35 or less, preferably 0.1 It is adjusted to be 0.3 or less.

  The elemental component and the composition ratio can be confirmed and quantitatively analyzed by X-ray Photoelectron Spectroscopy (XPS). By using together with sputter etching with Ar ions during XPS measurement, the depth profile of the layer can also be measured.

The organic-inorganic composite resin layer 3 can be formed using a method as shown in, for example, Patent Document WO2008 / 069217. Patent document WO2008 / 069217 is mainly composed of (a) a condensate of an organosilicon compound represented by R _n SiX _4-n , and (b) a metal chelate compound, a metal organic acid salt compound, two or more hydroxyl groups, or hydrolysis. A photosensitive compound sensitive to light having a wavelength of 350 nm or less and / or a compound derived therefrom, selected from the group consisting of metal compounds having a functional group, hydrolysates thereof, and condensates thereof (C) An organic-inorganic composite containing an ionizing radiation curable compound. Such an organic-inorganic composite is prepared by applying a paint containing the raw materials (a), (b), and (c) to the surface of the acrylic resin-silica hybrid layer 2, drying and removing the solvent, and then irradiating with ionizing radiation. And polymerized. The surface of the organic-inorganic composite resin layer 3 thus obtained is rich in inorganic oxide (siloxane) component. The organic-inorganic composite resin layer 3 has a gradient composition that is constant or gradually decreases from the surface in the depth direction.

  By these methods, since the region 5 rich in inorganic oxide components is formed on the surface of the organic-inorganic composite resin layer 3, the conventional intermediate layer having no such region 5 rich in inorganic oxide components is formed. In comparison, compatibility with the transparent inorganic oxide layer 4 laminated on the organic-inorganic composite resin layer 3 is improved, and excellent adhesion is exhibited.

  The transparent inorganic oxide layer 4 is configured as a transparent inorganic oxide layer in which a high refractive layer 6 and a low refractive layer 7 are laminated in order from the organic-inorganic composite resin layer 3.

  Any of these can be formed using any of various thin film forming methods (for example, sputtering method, electron beam method, ion beam method, vacuum deposition method, plasma CVD method, Cat-CVD method, MBE method, etc.). The sputtering method is suitably used for such applications that require uniformity in thickness and surface resistance. By carrying out these film formations, the total thickness of the transparent inorganic oxide layer 4 is set to 50 nm or more and 300 nm or less, here 243 nm. Each layer that is a constituent element of the transparent inorganic oxide layer 4 has predetermined transparency and refractive index, and is disposed to impart optical characteristics such as prevention of reflection of external light.

The high refractive layer 6 is a first layer of transparent inorganic material having a thickness of about 30 nm, if illustrated SiON or _SiO 2 -SnO ₂ based, _or may be a film of SiO 2 -TiO ₂ system. The refractive index of the high refractive layer 6 is set to about 1.6 to 2.4 (wavelength 630 nm), which is higher than the refractive index of the low refractive layer 7 described later.

The low refractive layer 7 is a second refractive layer in the transparent inorganic oxide, and is a second layer containing an inorganic component mainly composed of silicon oxide (SiO ₂ ). The refractive index is set to about 1.46 (wavelength 630 nm).

  As described above, the high refractive layer 6 and the low refractive layer 7 are configured as layers having different refractive indexes, and by using these, good optical properties (transparency) are imparted to the base sheet 1.

  The high refraction layer 6 and the low refraction layer 7 may be repeatedly laminated and disposed. However, if the number of laminations is increased too much, the base sheet 1 may be warped or the transparent inorganic oxide layer 4 may be cracked. It must be noted that it occurs.

<Embodiment 2> (Display Device)
FIG. 3 is a schematic cross-sectional view showing a configuration example of a display device using the light reflection preventing sheet 21 according to the embodiment of the present invention.

  The display device 20 is configured by sequentially laminating a polarizing plate unit 22 and a light reflection preventing sheet 21 on an LCD unit 23.

  The LCD unit 23 has an LCD 29 interposed between a pair of glass substrates 28. The LCD 29 can be a TFT type, a simple matrix type, or the like. The laminated structure of the LCD unit 23 is not limited to the above. Also, other types of displays such as CRT and PDP may be used.

  The polarizing plate unit 22 is formed by interposing a polarizer 26 between a pair of TAC (triacetyl cellulose) transparent substrates 25 and forming an HC layer 24 on the surface of the transparent substrate 25 on the upper surface side. The polarizing plate unit 22 is adhered to the upper surface of the LCD unit 23 with an adhesive layer 27.

  On the upper surface of the HC layer 24, the light reflection preventing sheet 21 is disposed so as to be laminated in the order of the base sheet 1, the first intermediate layer 2, the second intermediate layer 3, and the transparent inorganic oxide layer 4. .

  In the display device 20 having such a configuration, the light reflection preventing sheet 21 prevents incident light from the outside from being reflected on the display surface, and exhibits good transparency. For this reason, it can be expected that the image display performance inherent in the display device is exhibited.

<Embodiment 3> (Touch panel)
FIG. 4 is a schematic diagram showing a configuration example of a resistive touch panel 30 (hereinafter simply referred to as “touch panel 30”) using the light reflection preventing sheet 21 according to the embodiment of the present invention and an LCD combined therewith. FIG.

  As shown in FIG. 4, the touch panel 30 is formed by laminating a light reflection preventing sheet 21, a film 32 a, a spacer 35, a wiring substrate 36, a rib spacer 34, a film 32 b and the like in order from the top.

  An LCD 38 is laminated on the lower surface of the film 32b in the same order via an intermediate layer 37 composed of a plurality of layers including an adhesive layer and the like, and an LCD integrated touch panel is formed as a whole.

  Usually, the light reflection preventing sheet 21 and the film 32a are used by being bonded to the entire surface through the adhesive layer 31. The films 32a and 32b are arranged in pairs so that the transparent conductive films 33a and 33b formed on one side face each other at a predetermined interval.

  Around the transparent conductive films 33a and 33b, a rib spacer 34 made of any one of an adhesive material, an adhesive sheet, and a double-faced tape having an adhesive material layer on both surfaces of a plastic film is disposed. Thereby, normally, the transparent conductive films 33a and 33b are arranged to face each other so as to be spaced apart from each other.

  Further, hemispherical protrusion spacers 35 are arranged in a matrix at regular intervals on the surface of the transparent conductive film 33b, so that unnecessary contact between the transparent conductive films 33a and 33b is avoided. A wiring substrate 36 is interposed between the transparent conductive films 33a and 33b.

  In addition, the structure of the touchscreen of this invention is not limited to the structure of FIG. 4, For example, the glass substrate may be sufficient as the films 32a and 32b in which a transparent conductive film is formed. Further, the number of laminated films and the glass substrate, the order of lamination, and the like can be appropriately changed and adjusted.

  Furthermore, the input method of the touch panel 30 to which the present invention is applied may be any method, for example, a capacitance type. Of course, the display combined with the touch panel 30 is not limited to the LCD, but may be other types of displays such as CRT, organic EL, PDP, and electronic paper.

  Here, the main feature of the touch panel 30 of the present embodiment is that the sheet of the present invention is used for the light reflection preventing sheet 21. The light reflection preventing sheet 21 has improved adhesion between the transparent inorganic oxide layer 4 that exhibits the reflection preventing function and the base sheet 1. For this reason, the ionizing radiation curable organic-inorganic composite even if the film continuously receives relatively high energy light on the short wavelength side of ultraviolet rays or visible light during use or storage of the touch panel 30 By preventing peeling between the resin layer 3 and the transparent inorganic oxide layer 4 and exhibiting excellent light resistance for a long period of time, a stable form can be maintained.

  Therefore, by obtaining such an effect, the touch panel 30 is used in a field where the ultraviolet irradiation amount is relatively large, or used in a car navigation system that is likely to be in a high temperature environment, and light with a wavelength of 300 nm to 550 nm is emitted. Even when continuously used in an environment where irradiation is continuously performed, stable input characteristics can be maintained over a long period of time.

<Preliminary examination (examination of intermediate layer thickness)>
The thickness condition of the intermediate layer material used in Examples and Comparative Examples was examined. Each material, application condition, and thickness condition are described below.

1. Material of intermediate layer 8 and curing conditions 1-1. Material of Acrylic Resin-Silica Hybrid Layer 2 As a material of the acrylic resin-silica hybrid layer 2, “COMPOCERAN AC601” manufactured by Arakawa Chemical Industries, Ltd. was adopted. The curing condition was drying at 120 ° C. for 5 minutes.

1-2. Material of organic-inorganic composite resin layer 3 1-2-1. Organic inorganic composite resin A (UV curable)
As the material of the organic-inorganic composite resin 3, a material prepared by the following procedure was adopted.

(1). Photosensitive compound Diisopropoxybisacetylacetonate titanium (Nippon Soda Co., Ltd., T-50, solid content of titanium oxide equivalent: 16.5% by weight) 30.3 g of ethanol / ethyl acetate / 2-butanol = 60 / After dissolving in 58.4 g of a 20/20 mixed solvent, 11.3 g of ion-exchanged water (10-fold mol / mol of titanium oxide) was slowly added dropwise with stirring to cause hydrolysis. One day later, the solution was filtered to obtain a yellow transparent titanium oxide nano-dispersion [A-1] having a titanium oxide equivalent concentration of 5% by weight. The average particle size of titanium oxide was 4.1 nm and was monodispersed.

(2). Organosilicon compound Vinyltrimethoxysilane [B-1] (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-1003) was used as the organosilicon compound.

(3). (Photosensitive compound + silane compound hydrolyzed condensate) mixed solution Liquid [C- mixed with the above [A-1] and [B-1] so as to have an element ratio (Ti / Si = 1/9) 1] was produced. The solid content of [C-1] was 27% by weight.

(4). Ultraviolet curable compound solution As an ultraviolet curable compound, a mixture of ethanol / ethyl acetate / 2-butanol = 60/20/20 so that a urethane acrylate oligomer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., purple light UV7600B) is 30% by weight. Dissolved in solvent. As a photopolymerization initiator, 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved in this solution so as to be 4% by weight based on the solid content of the urethane acrylate oligomer, and the solution [D -1] was produced.

(5). Preparation of organic-inorganic composite resin [C-1] solution and [D-1] solution so that the solid content ratio is 10% by weight / 90% by weight = [C-1] / [D-1] Were mixed to prepare a coating film forming solution [E-1]. The material obtained as described above is referred to as “organic-inorganic composite resin A”. The curing conditions were such that the ultraviolet rays were irradiated at 500 mJ / cm ² after drying at 80 ° C. for 2 minutes.

1-2-2. Organic inorganic composite resin B (thermosetting type)
As a comparative material for the organic-inorganic composite resin 3, a thermosetting sol-gel liquid (trade name “NSC2451”, hereinafter referred to as “organic-inorganic composite resin B”) manufactured by Nippon Seika Co., Ltd. was employed. The curing condition was drying at 120 ° C. for 5 minutes.

2. Determining the thickness of the intermediate layer 8 As described below, the thickness of each layer of the intermediate layer 8 was determined while changing the coating conditions of the bar coat. MCPD-3000 manufactured by Otsuka Electronics Co., Ltd. was used for the thickness measurement.
2-1. Determination of the thickness condition of the acrylic resin-silica hybrid layer 2 As a bar coating bar, a SA-203 bar coater manufactured by Tester Sangyo Co., Ltd., having a shaft diameter of 12.7 mm was used. ROD No. Was fixed to 10 and the coating liquid (Arakawa Chemical Industries, Ltd. “Composeran AC601”) was diluted with MEK to change the thickness.

2-2. Determining the thickness condition of the organic / inorganic composite resin layer 3 The coating liquid (the organic / inorganic composite resin A and the organic / inorganic composite resin B) is not diluted, but a bar coating bar (SA-203 manufactured by Tester Sangyo Co., Ltd.) ROD No. While changing the thickness, the thickness was changed.

  Since the surface hardness may be lowered by applying these intermediate layer materials, it is preferable that the coating thickness is thinner. The thickness of the acrylic resin-silica hybrid layer 2 was set to 100 nm or less, and the total thickness of the acrylic resin-silica hybrid layer 2 and the organic-inorganic composite resin layer 3 was also set to a range of 1000 nm or less. However, if the organic-inorganic composite resin A is too thin, there is a possibility of poor curing.

As described above, Composelan AC601 is a 1/20 diluted solution, and the organic-inorganic composite resin A is ROD No. 10, the organic-inorganic composite resin B is ROD No. The film thickness formed in Step 4 is set as a basic setting condition, and Examples and Comparative Examples performed in this range will be described in detail below.

<Example 1>
Samples of Examples and Comparative Examples were prepared according to the following procedure.

(Creation of base sheet 1)
As an ionizing radiation curable acrylic resin material, a mixture of 75 parts by weight of pentaerythritol triacrylate (PET-3A) and 25 parts by weight of trifunctional urethane acrylate (New Frontier R1302 manufactured by Daiichi Kogyo Seiyaku) was prepared. This was mixed with 5 parts by weight of a photopolymerization initiator (Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd.) to prepare an ionizing radiation curable coating paste 11.
For this coating paste 11, two transparent PET films not subjected to any surface treatment are prepared, and a bar (Tester Sangyo Co., Ltd.) is provided on the surface of one PET film (first film substrate 10). SA-203 ROD. No 200). On the surface of the obtained coating film (paste layer 12), the other PET film (second film base material 13) was placed and bonded (the laminated body of this PET film / coating film / PET film was “laminated body”). A ”). Since the coating film has fluidity, when performing the installation bonding, the coating film was bonded with as low a pressure as possible so that the predetermined thickness of the coating film was maintained. In addition, care was taken so that no bubbles would enter between the PET films.

  Subsequently, the coating film was cured by irradiating the laminate A with ultraviolet rays from the outside for about 10 seconds using a high-pressure mercury lamp (tube length: 1200 mm, output power: 15 kW). After the completion of curing, the base sheet 1 used for the sample was obtained by peeling and removing the two PET films from the laminate A (this is referred to as “molded body A”). While the molded body A had moderate flexibility, the pencil hardness was 9H, and it was confirmed that the molded body A had a very high hardness.

(Preparation of acrylic resin-silica hybrid layer 2)
The base sheet 1 having a thickness of 200 μm formed by the above manufacturing method is subjected to a corona treatment by passing it under 0.6 kw output at 2 m / min, and a 5% solid component solution of COMPOCERAN AC601 is prepared by SA-203 ROD manufactured by Tester Sangyo Co. No. The film was applied with 10 bars and dried at 120 ° C. for 5 minutes to obtain a film of 100 nm or less.

(Preparation of organic-inorganic composite resin layer 3)
The organic-inorganic composite resin A was added to SA-203 ROD No. The film was applied using a 10 bar, dried at 80 ° C. for 2 minutes, and then cured by irradiation with ultraviolet rays of 500 mJ / cm ² to obtain a 3369 nm film. The element number ratio measurement result by XPS of this surface was (Si + Ti) /C=0.16. In addition, the element number ratio measurement result of the deep layer portion of 3 μm or more from the film surface obtained here was (Si + Ti) /C=0.12.

(Preparation of transparent inorganic oxide layer 4)
A first layer to a fourth layer constituting the inorganic oxide layer 4 shown below were sequentially laminated. For each of these layers, a film to be deposited is placed inside a sputtering apparatus, the substrate temperature is set to 60 ° C., the inside of the apparatus is decompressed, Ar gas and O ₂ gas are introduced, and various ceramic targets are used. Formed.

The first layer (high refractive layer) was a niobium oxide (Nb ₂ O ₅ ) layer having a thickness of 13 nm and a refractive index of 2.3. The second layer (low refractive layer) was a silicon oxide (SiO ₂ ) layer having a thickness of 28 nm and a refractive index of 1.46. The third layer (high refractive layer) was a niobium oxide (Nb ₂ O ₅ ) layer having a thickness of 112 nm and a refractive index of 2.3. The fourth layer (low refractive layer) was a silicon oxide (SiO ₂ ) layer having a thickness of 90 nm and a refractive index of 1.46.

<Example 2>
In the sample of Example 1, a different configuration was created separately only in that the thickness of the organic-inorganic composite resin A was set to 8566 nm (using a bar of ROD No. 14).

<Example 3>
In the sample of Example 1, a different configuration was created separately only in that the thickness of Composeran AC601 was 1758 nm (using the stock solution).

<Comparative Example 1>
In the sample of Example 1, a different configuration was created separately only in that the organic-inorganic composite resin A was omitted.

<Comparative Example 2>
In the sample of Example 1, the thickness of Compocellan AC601 was set to 1758 nm (stock solution was used), and a different configuration was separately prepared only in that the organic-inorganic composite resin A was omitted.

<Comparative Example 3>
In the sample of Example 1, an organic-inorganic composite resin B was used for the ionizing radiation curable organic-inorganic composite resin layer, and a different structure was separately created except that the thickness was 749 nm (ROD No. 4 bar was used). did.

<Comparative Example 4>
In the sample of Example 1, an organic-inorganic composite resin B was used for the organic-inorganic composite resin layer 3, and a different configuration was separately created only in that the thickness was 3653 nm (ROD No. 14 bar was used).

<Comparative Example 5>
In the sample of Example 1, the thickness of Composeran AC601 is 1758 nm (using the stock solution), the organic-inorganic composite resin B is used for the organic-inorganic composite resin layer 3, and the thickness is 749 nm (using the bar of ROD No. 4). A different configuration was created separately.

[Evaluation of adhesion]
Each of the samples prepared above was subjected to ultraviolet irradiation treatment for a predetermined time (maximum 528 hours) using an ultraviolet fade meter (light source is carbon arc) manufactured by Suga Test Instruments Co., Ltd. Trademark) ”was attached, the tape was peeled off instantaneously in a direction perpendicular to the film surface in a time of 0.5 to 1.0 seconds, and the presence or absence of film peeling was visually observed. Only the case where film peeling did not occur was considered good. The evaluation results are shown in Table 3.

  In Examples 1 to 3, by using the organic-inorganic composite resin A for the organic-inorganic composite resin layer 3, there is no dependency on the thickness of the acrylic resin-silica hybrid layer 2 or the organic-inorganic composite resin layer 3, and good It was confirmed that excellent peeling durability was exhibited.

  On the other hand, Comparative Examples 1 and 2 include the acrylic resin-silica hybrid layer 2 using the same composeran AC601 as in Examples 1 to 3, but the organic / inorganic composite resin layer 3 does not intervene so that the peeling durability is achieved. Decreased. The effect of thickening the acrylic resin-silica hybrid layer 2 was not observed.

  This difference is due to the presence of the organic-inorganic composite resin layer 3, so that there is a large amount of inorganic oxide in the region in the vicinity of the surface in contact with the transparent inorganic oxide layer 4 of the organic-inorganic composite resin layer 3. In the region in the vicinity of the surface in contact with the resin-silica hybrid layer 2, there are many organic components, the constituent components of each adjacent layer are similar, and the affinity with the upper and lower layers of the organic-inorganic composite resin layer 3. This is thought to be due to a marked improvement.

  Here, apart from the above evaluation, samples of a configuration in which only the organic-inorganic composite resin A and only the organic-inorganic composite resin B were coated on the base sheet 1 were also produced. The peel durability of the total layer structure including the transparent inorganic oxide layer 4 was not evaluated.

  Further, Comparative Examples 3 and 4 and 5 are provided with the acrylic resin-silica hybrid layer 2 using the same composeran AC601 as in Examples 1 to 3, but the organic-inorganic composite resin B is used for the organic-inorganic composite resin layer 3. As a result, the peeling durability decreased.

  In Comparative Example 4, the thickness of the organic-inorganic composite resin layer 3 was made thicker than the standard thickness condition, and the peel durability was improved as compared with Comparative Example 3. Although the effect of film formation was confirmed, it did not reach the performance of Examples 1 to 3.

  In Comparative Example 5, the thickness of the acrylic resin-silica hybrid layer 2 is thicker than the standard thickness condition, and the peeling durability is the same as that of Comparative Example 3, and the effect of thickening the acrylic resin-silica hybrid layer 2 is observed. I couldn't.

  From the above experimental results, the superiority of the present invention over the prior art was confirmed.

  The antireflection sheet according to the present invention can be used by being attached to the surface of various display devices such as a display and a touch panel, and the base sheet is chemically stable and the adhesion of the antireflection film is good. It can also be applied to cases where durability of the display device surface is required.

1 Base sheet 2 Acrylic resin-silica hybrid layer (first intermediate layer)
3 Organic-inorganic composite resin layer (second intermediate layer)
4 Transparent inorganic oxide layer 5 Inorganic oxide component rich region 6 High refractive layer 7 Low refractive layer 8 Intermediate layer 21 Light reflection preventing sheet

Claims (10)

A base sheet made of an ionizing radiation curable acrylic resin, an intermediate layer provided on the base sheet, and a transparent inorganic oxide layer provided on the intermediate layer,
The intermediate layer is formed by sequentially laminating an acrylic resin-silica hybrid layer and an ionizing radiation curable organic-inorganic composite resin layer from the base sheet side ,
The acrylic resin-silica hybrid layer has a raw material containing a silica precursor .   The organic-inorganic composite resin layer includes both an organic component and an inorganic oxide, and at least the number of organic elements in the organic component of the layer in a region within a depth of 10 nm from the surface in contact with the transparent inorganic oxide layer 2. The light reflection preventing sheet according to claim 1, wherein the ratio B / A of the number B of inorganic elements in the inorganic oxide to A is 0.05 to 0.35 in terms of the number ratio of elements.   The inorganic oxide component contained in the organic-inorganic composite resin layer contains at least one element of Si, Ti, Zr, Sn, Sb, and Al, and the ratio B / A is the organic-inorganic composite. It is the element number ratio (Si + Ti + Zr + Sn + Sb + Al) / C) of the sum of each element constituting the inorganic oxide component contained in the resin layer and carbon of the organic component, and the ratio B / A is the organic-inorganic composite The light reflection preventing sheet according to claim 2, wherein the resin layer is set to be constant or gradually decreased from the surface toward the depth direction.   The organic-inorganic composite resin layer has an average primary particle diameter of 5 to 40 nm, and contains 20% by weight of inorganic oxide fine particles made of at least one of SiO2, TiO2, ZrO2, SnO2, ATO, and Al2O3. The light reflection preventing sheet according to claim 1, wherein the light reflection preventing sheet is dispersed in a range of 90% by weight or less.   The said organic-inorganic composite resin layer is 3000 nm or more and 9000 nm or less in thickness, The light reflection preventing sheet of Claims 1-4 characterized by the above-mentioned. The transparent inorganic oxide layer, an antireflection sheet of claim 1 to 5, characterized in that it has a multilayer structure formed by laminating at least two or more different layers. The transparent inorganic oxide layer is formed by laminating a second layer having a second refractive index different from the first refractive index and a first layer having a first refractive index in the same order. The light reflection preventing sheet according to claim 6 , wherein two or more layers are laminated repeatedly. Display a light anti-reflection sheet was stuck or adhered to the outermost surface of claim 1-7. Touch panel stuck or adhered to the outermost surface of the antireflection sheet of claim 1-7. A paste application step of forming a paste layer by applying a precursor paste of an ionizing radiation curable acrylic resin to the surface of the first film substrate that is continuously drawn, and a second film base on the paste layer A wet laminating step for laminating a material, a resin curing step for forming an ionizing radiation curable acrylic resin film by irradiating the paste layer with ionizing radiation after the laminating step and curing the paste layer, and the resin curing step Thereafter, a peeling step of peeling the first and second film bases from the ionizing radiation curable acrylic resin film to obtain a base sheet, and applying an acrylic resin-silica hybrid containing a silica precursor on the base sheet. Resin curing step to form the first intermediate layer by curing A resin curing step of forming a second intermediate layer by applying and curing an ionizing radiation curable organic-inorganic composite resin, and a thin film forming step of forming a transparent inorganic oxide layer on the intermediate layer The manufacturing method of the light reflection preventing sheet characterized by including.