JP4618550B2 - Optical filter for optical film and plasma display panel - Google Patents

Description

  The present invention is a multi-functional film having low surface reflectivity, neutral antireflection, transparency, scratch resistance, antistatic properties, near-infrared shielding, and color tone correction capability on a single base film. The present invention relates to an optical film, and further to an optical filter for a plasma display panel using the optical film.

  The optical filter provided on the front of the plasma display panel (hereinafter referred to as PDP) prevents damage to the panel, shields electromagnetic waves that affect the human body and other electrical devices leaking from the PDP, and shields near infrared rays that affect the remote control. Color tone correction by absorption of visible light at a wavelength of about 590 nm, which reduces the red purity associated with the emission of neon gas, reflection on the surface of external light such as sunlight and fluorescent lamps, and surface reflection prevention to prevent reflection, Functions such as scratch resistance, antistatic properties and antifouling properties are required.

  A typical optical filter for PDP includes a semi-strengthened glass plate serving as a substrate bonded with an electromagnetic wave shielding film, a near-infrared shielding / color tone correction film, an antireflection film and the like with an adhesive.

  Generally, as a means to prevent surface reflection and reflection of external light such as sunlight and fluorescent lamps of the display, unevenness is provided on the surface of the display to diffuse external light, or thin films with high and low refractive indexes are alternately used. A method of preventing the reflection of light by laminating the layers is used. However, the method of irregularly reflecting external light is insufficient in terms of improving the visibility of the image because the image on the display looks blurred.

  As a method for improving this, an antireflection film has been proposed in which a hard coat layer, a high refractive index layer, and a low refractive index layer are sequentially provided on the surface of a transparent film from the lower layer side (see Patent Document 1, etc.). However, in this method, if the refractive index difference between the high refractive index layer and the low refractive index layer is large, the reflectance is relatively higher in the visible light region in the low wavelength region or in the high wavelength region than in the vicinity of the lowest reflectance. The light is tinged with blue or red, and there is a problem in the purity of the color tone. In addition, since the conductive metal oxide fine particles contained in the high refractive index layer are many and the film thickness is thin, the haze as an antireflection film is increased to reduce the clearness of the image, and the surface is uneven. There arises a problem that the surface hardness and chemical resistance are lowered, and the cost is increased due to the large number of laminated layers.

  In addition, a method of sequentially laminating porous silica and a polysiloxane polymer on the antiglare hard coat layer has been proposed (see Patent Document 2).

  However, this method has a problem that the antiglare hard coat layer has a high haze, and the clearness of the image is impaired when used as an antireflection film for an image display device. In addition, if the refractive index of the polysiloxane polymer is not sufficiently low, it is difficult to suppress reflection in the entire visible light region, and the reflectance increases in the low or high wavelength region of the visible light region. There arises a problem that the color of light is not neutral.

  On the other hand, as a near-infrared shielding film, a method of shielding a near-infrared ray by coating a transparent film with a composition in which a pigment that absorbs near-infrared rays is dispersed in a transparent polymer resin binder is performed (Patent Documents 3 and 4). Etc.) Furthermore, a color tone correction is also performed by coating a composition in which a transparent polymer resin binder is dispersed with a dye that absorbs visible light near 590 nm, which reduces red purity (see Patent Documents 5 and 6).

  In order to popularize the PDP, it is desired to reduce the price of the optical filter for the PDP together with the panel. One method is to provide a near-infrared shielding layer on the surface opposite to the anti-reflection layer of the anti-reflection film, which has been bonded to the anti-reflection film and the near-infrared shielding film with an adhesive. A reduction in the number of materials and the bonding process has been proposed by integrating the functions of antireflection and near-infrared shielding on a single film (see Patent Document 7, etc.).

However, these antireflection layers have problems that the color tone of the reflected light is not neutral as described above, and the surface scratch resistance is not at a satisfactory level. Further, a higher shielding performance is required for the near infrared shielding layer, and it is also required to provide not only the near infrared shielding but also a color tone correction function for increasing the contrast of the image.
JP 2001-350001 A JP 2003-139908 A Japanese Patent Laid-Open No. 11-326631 Japanese Patent No. 3308545 JP 58-153904 A Japanese Patent No. 3311720 Japanese Patent Laid-Open No. 10-156991

  In view of the background art, the present invention is directed to an antireflection layer having low surface reflectance on one surface of a base film, neutral antireflection and transparency, scratch resistance, and antistatic properties. By providing a near-infrared shielding layer with excellent near-infrared shielding performance and a color tone correction function to improve red purity on the side surface, one film has anti-reflection, near-infrared shielding, and color tone correction functions. It is intended to provide a multifunctional optical film having both of them, and to provide a lower cost optical filter for PDP by using the optical film of the present invention.

  The present invention employs the following means in order to solve such problems. That is, the optical film of the present invention has an A layer having a film thickness of 0.3 μm or more and a refractive index of 1.62 or less on one surface of the base film, and a refractive index lower than that of the A layer, and At least two of the B layers of 1.42 or less are laminated at a position where the A layer is closer to the base film than the B layer, and the other surface of the base film has a near-infrared absorbing ability. In an optical film formed by laminating a C layer formed by dispersing a pigment in a transparent polymer resin, the surface reflection spectrum of the B layer at a wavelength of 400 to 700 nm is (1) the minimum reflectance is 0.6% or more. 2.0% or less, (2) the maximum reflectance is 3.5% or less, (3) the difference between the maximum reflectance and the minimum reflectance is 2.5% or less, and all three conditions are satisfied, and the C The layer has (4) a transmittance of 20% or less at a wavelength of 820 nm, and (5) a wavelength of 85. nm transmittance of 15% or less in, (6) transmittance at 1150nm wavelength 950nm of 10% or less, an optical film that satisfies all three conditions.

  Further, the present invention is an optical filter for a plasma display panel, which uses the optical film of the present invention and is bonded to a film having an electromagnetic wave shielding ability or an impact absorbing ability, or a glass plate.

  According to the present invention, it is possible to provide an optical film having both an antireflection layer excellent in antireflection properties and scratch resistance, and a near infrared shielding layer excellent in near infrared shielding properties and color tone correction capability. It becomes possible to provide an optical filter for PDP that can reduce the price as well as performance.

  FIG. 1 is a schematic cross-sectional view showing an example of a preferred embodiment of the optical film of the present invention.

  As an example of a preferred embodiment of the present invention, an antireflection layer composed of at least two layers of an A layer and a B layer is laminated on one surface of a base film. Further, a C layer in which a pigment having near infrared absorption ability is dispersed in a transparent polymer resin binder is laminated on the surface of the base film opposite to the antireflection layer. The C layer may further have a color tone correction function by containing a dye that absorbs visible light having a wavelength of about 590 nm in order to prevent a decrease in red purity associated with emission of neon gas. Further, a transparent adhesive layer for laminating with other optical filter elements such as semi-tempered glass or electromagnetic wave shielding film is laminated thereon.

  In the optical film of the present invention, an antireflection layer comprising at least two layers of A layer and B layer is first laminated on one surface of a base film, and after first producing the antireflection film, the opposite of the base film It is preferable to laminate a C layer on the surface. By doing so, the near-infrared absorbing dye can be exposed to actinic rays such as ultraviolet rays used when forming the A layer and the B layer.

  As the substrate film used in the present invention, a film that can be formed into a melt or a solution is preferably used. Specific examples thereof include films made of polyester, polyolefin, polyamide, polyphenylene sulfide, acetate, polycarbonate, acrylic resin, and the like. Among these, a film made of a thermoplastic resin excellent in transparency, mechanical strength, dimensional stability, etc. is particularly preferable. For use in an optical film, it is preferable that the light transmittance is high and the haze value is low. A film composed of at least one selected from polyester, acetate and acrylic resin is preferred. In view of transparency, haze value, and mechanical properties, a film made of polyester is particularly preferably used.

  For example, the light transmittance at 400 to 800 nm of the substrate film is preferably 40% or more, more preferably 60% or more. The haze value of the substrate film is preferably 5% or less, more preferably 3% or less. Satisfying both of these conditions is more preferable in terms of sharpness when used as a member for an image display device. Further, the upper limit of the light transmittance is about 99.5%, and the lower limit of the haze value is about 0.1%.

  Examples of the polyester preferably used in the present invention include polyethylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, and polypropylene naphthalate. Two or more of these may be mixed. In addition, these may be a polyester copolymerized with other dicarboxylic acid components and diol components, but the copolymerization ratio is preferably 25% or more in the degree of crystallinity in a film in which crystal orientation is completed. More preferably, the range is 30% or more, and more preferably 35% or more. When the crystallinity is less than 25%, dimensional stability and mechanical strength tend to be insufficient. The degree of crystallinity can be measured by a Raman spectrum analysis method.

  The base film used in the present invention may be a composite film having a laminated structure of two or more layers. As the composite film, for example, a composite film that is substantially free of particles in the inner layer portion and provided with a layer containing particles in the surface layer portion, has coarse particles in the inner layer portion, and fine particles in the surface layer portion. And a composite film having a layer in which the inner layer portion contains fine bubbles. In the composite film, the polymer constituting the inner layer portion and the surface layer portion may be a chemically different polymer or the same kind of polymer.

  The base film in the present invention is a film that is crystallized by biaxial stretching from the viewpoint of ensuring sufficient thermal stability, particularly dimensional stability and mechanical strength of the film, and improving flatness. preferable. The crystal orientation by biaxial stretching means that the thermoplastic film before unstretched, that is, before the crystal orientation is completed, is preferably stretched about 2.5 to 5 times in the longitudinal direction and the width direction, respectively, and then heat-treated. The crystal orientation is completed by the above, and it indicates a biaxial orientation pattern by wide-angle X-ray diffraction.

  The thickness of the base film used in the present invention is preferably 10 to 500 μm, more preferably 20 to 300 μm, from the viewpoint of mechanical strength and handling properties.

  The base film of the present invention may contain various additives, resin compositions, cross-linking agents and the like within a range that does not impair the effects of the present invention. For example, antioxidants, heat stabilizers, UV absorbers, organic and inorganic particles, pigments, dyes, antistatic agents, nucleating agents, acrylic resins, polyester resins, urethane resins, polyolefin resins, polycarbonate resins, alkyd resins, epoxy resins , Urea resin, phenol resin, silicone resin, rubber resin, wax composition, melamine crosslinking agent, oxazoline crosslinking agent, methylolated, alkylolized urea crosslinking agent, acrylamide, polyamide, epoxy resin, isocyanate compound , Aziridine compounds, various silane coupling agents, various titanate coupling agents, and the like.

  Among these, when inorganic particles such as silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate, barium sulfate, carbon black, zeolite, titanium oxide, metal fine powder, etc. are added, it is easy to slip. This is particularly preferable since the property and scratch resistance are improved. The average particle size of the inorganic particles is preferably 0.005 to 5 μm, more preferably about 0.05 to 1 μm. The particle diameter here is a value obtained using a laser diffraction particle size distribution measuring apparatus. The average particle size is 50% distributed particle size. The 50% distribution particle size refers to the particle size where the particle size distribution is 50%, and the average particle size refers to this particle size unless otherwise specified. Moreover, the addition amount of inorganic particles is 0.05 to 20 parts by mass, preferably 0.1 to 10 parts by mass in 100 parts by mass of the base film.

  The base film used in the present invention preferably has an easy-adhesion layer formed on at least one surface of the base film for the purpose of improving the adhesiveness with the A layer or the C layer. It is still more preferable that it is formed. The easy-adhesion layer as used in the field of this invention means the film-form thing which is formed in the laminated structure on the surface of a base film. The component constituting the easy-adhesion layer is not particularly limited as long as it has sufficient adhesiveness with the A layer or the C layer, but is not limited to polyester resin, polycarbonate resin, epoxy resin, alkyd resin, acrylic resin, urea resin, urethane. Resins and the like can be suitably used. In particular, when a film substrate made of polyester is used, it is more preferable to use a resin selected from a polyester resin, an acrylic resin, and a urethane resin from the viewpoint of adhesion, and two different resins, for example, a polyester resin and a urethane are used. A combination of resin, polyester resin and acrylic resin, or acrylic resin and urethane resin may be used. Moreover, it is more preferable to use a different resin from the point of adhesiveness for the easy-adhesion layer formed on each surface of the base film. For example, it is preferable to use a polyester resin on the A layer side and an acrylic resin on the C layer side.

Since the easy-adhesion layer generates interference fringes, it is necessary to devise measures to reduce them. For this purpose, the refractive index of the easy adhesion layer satisfies (refractive index of easy adhesion layer) = {(refractive index of base film) × (refractive index of layer A or C)} ^1/2 ± 0.02. Is preferable from the viewpoint of reducing interference fringes, and when the base film is polyester, the refractive index of the easy-adhesion layer is preferably 1.53 to 1.60.

  When a base film is melt-extruded and then biaxially stretched to form a film, an easy-adhesion layer is preferably applied on both sides in the previous stage of the transverse stretching process of the film-forming process and formed simultaneously with the film formation. Used. In that case, the above-described resin is preferably applied as an aqueous emulsion paint, and the thickness of the easy-adhesion layer is preferably 0.03 to 0.20 μm.

  In the present invention, in order to obtain an antireflection layer having a low surface reflectance and a neutral color, at least two layers of the A layer and the B layer satisfying specific conditions of the refractive index are arranged in the direction of the A layer from the B layer. Is laminated at a position close to the base film, and it is important that the A layer and the B layer satisfy the minimum reflectance and the maximum reflectance of the optical film under specific conditions.

  The specific conditions of the minimum reflectance and the maximum reflectance of the optical film referred to here are: (1) the minimum reflectance is 0.6% or more and 2.0% or less in the surface reflection spectrum at a wavelength of 400 to 700 nm. (2) The maximum reflectance is 3.5% or less, and (3) the difference between the maximum reflectance and the minimum reflectance is 2.5% or less. That is, in order to obtain an antireflection effect effective in the visible light region, the maximum reflectance of the surface reflection spectrum that can be placed at a wavelength of 400 to 700 nm needs to be 3.5% or less. In order to prevent the reflected color from having a specific color tone, the minimum reflectance is 0.6% or more and 2.0% or less, and the difference between the maximum reflectance and the minimum reflectance is 2.5. % Or less is necessary. More preferably, in addition to satisfying the condition (1) of the surface reflection spectrum that can be placed at a wavelength of 500 to 700 nm, (2) the maximum reflectance is 2.2% or less, and (3) the maximum reflectance and the minimum reflectance The condition is that the difference is 1.5% or less. The reflectance measuring method here is as defined later.

Further, the antireflection layer in the present invention is often installed and used on the outermost surface of the PDP. In that case, it is preferable that the scratch resistance is grade 3 or higher, since it is difficult to scratch when dust or the like adhering to the surface of the antireflection layer is wiped off with a cloth. Preferably it is quaternary or higher. Scratch resistance is determined by applying a load of 250 g to # 0000 steel wool on the surface of the antireflection layer and rubbing it 10 times at a stroke width of 10 cm and a speed of 30 mm / sec. Is evaluated in the following five stages.
5th grade: No scratches.
Fourth grade: 1 to 5 scratches.
3rd grade: 6 to 10 scratches.
Second grade: 11 or more scratches.
First grade: Countless scratches on the entire surface.

Furthermore, in order to prevent dust and dust from adhering to the antireflection layer, the resistance value of the antireflection layer side surface of the present invention is preferably 1 × 10 ¹² Ω / □ or less, more preferably 1 × 10 ¹¹ Ω. It is preferable to have the following antistatic properties.

  Further, the haze of the optical film of the present invention is preferably 1.5% or less, and more preferably 0.5% or less in order to obtain a clearer image.

  In order to obtain the optical film having the above characteristics, the present invention can be achieved by forming an antireflection layer described below.

  In the optical film of the present invention, it is necessary to laminate at least two layers of the A layer and the B layer on at least one surface of the base film, and the A layer having a higher refractive index than the B layer is close to the base film. It is necessary to laminate them. If the stacking order is different, the antireflection function is not provided.

  In addition, another layer may be provided between the A layer and the base film, between the A layer and the B layer, and between the B layer and the surface, as long as the antireflection function is not hindered. From the viewpoint of productivity including color tone and cost, it is preferable that the A layer is provided on the base film and the B layer is provided thereon. The refractive index measurement method here is as defined later.

  The A layer of the present invention needs to have a thickness of 0.3 μm or more, a refractive index of 1.62 or less, and higher than the B layer. When the refractive index of the A layer is higher than 1.62, the maximum reflectance exceeds 3.5%, the reflected light in a specific wavelength region becomes relatively strong, and a neutral color tone cannot be realized. Further, when the refractive index of the A layer is lower than that of the B layer, it has no antireflection ability. Further, the refractive index of the A layer is preferably 1.48 or more in order to suppress an increase in the minimum reflectance.

  If the film thickness of this A layer is less than 0.3 μm, the difference between the maximum reflectance and the minimum reflectance in the 400 to 700 nm region becomes large, and it becomes difficult to obtain a neutral color tone.

  As a composition for forming the refractive index of the A layer in a layer having a refractive index of 1.62 or less, various resin components may be one component system or mixed to be any multi-component resin component. Any composition may be used, such as a mixture of pigment, metal oxide fine particles and other additives in an arbitrary ratio. However, in order to prevent dust from adhering to the surface of the optical film of the present invention, the conductive component is added to this composition. A composition contained in the A layer is preferred.

  As the resin component constituting the A layer, a resin component such as an acrylic resin, a urethane resin, a melamine resin, an organic silicate compound, a silicone resin, a phosphorus-containing resin, a sulfide-containing resin, or a halogen-containing resin can be used alone or Although a mixed system can be used, it is particularly preferable to use a silicone resin and an acrylic resin from the viewpoints of hardness and durability. Furthermore, from the viewpoint of curability, flexibility, and productivity, an acrylic resin is preferable, and an active ray curable acrylic resin or a thermosetting acrylic resin is more preferable. Particularly preferably, among such acrylic resins, the (meth) acrylate resin is easily radically polymerized by irradiation with actinic rays, and may exhibit the effect of improving the solvent resistance and hardness of the formed film. Most preferably, a (meth) acrylate resin having a (meth) acryloyl group composed of two or more polyfunctional (meth) acrylate compounds in the molecule may improve solvent resistance. For example, as such (meth) acrylate resin, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, ethylene-modified trimethylolpropane tri (meth) acrylate, tris- ( 2-hydroxyethyl) -isocyanuric acid ester tri (meth) acrylate such as tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Tetrafunctional or higher functional (meth) acrylates may be mentioned.

  In order to improve the dispersibility of the particles, a (meth) acrylate compound (monomer) having an acidic functional group such as a carboxyl group, a phosphate group, or a sulfonate group can be used for the resin component of the A layer. . Specifically, as the acidic functional group-containing monomer, unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethylphthalic acid, Examples thereof include phosphoric acid (meth) acrylic acid esters such as mono (2- (meth) acryloyloxyethyl) acid phosphate and diphenyl-2- (meth) acryloyloxyethyl phosphate, and 2-sulfoester (meth) acrylate. In addition, a (meth) acrylate compound having a polar bond such as an amide bond, a urethane bond, or an ether bond can be used. Furthermore, a resin having a urethane bond, such as a urethane (meth) acrylate oligomer, is particularly preferable because of its high polarity and good particle dispersibility.

  In forming the A layer in the present invention, an initiator may be used to advance curing of the applied binder component. As the initiator, the applied binder component initiates or accelerates polymerization and / or crosslinking reaction by radical reaction, anion reaction, cation reaction, etc., and various conventionally known photopolymerization initiators can be used. is there. Specific examples of the photopolymerization initiator include sulfides such as sodium methyldithiocarbamate sulfide, diphenyl monosulfide, dibenzothiazoyl monosulfide and disulfide, thioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, Thioxanthone derivatives such as 2,4-diethylthioxanthone, azo compounds such as hydrazone and azobisisobutyronitrile, diazo compounds such as benzenediazonium salt, benzoin, benzoin methyl ether, benzoin ethyl ether, benzophenone, dimethylaminobenzophenone Michler's ketone, benzylanthraquinone, t-butylanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-aminoanthraquinone, Aromatic carbonyl compounds such as -chloroanthraquinone, dialkylaminobenzoic acid esters such as methyl p-dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, butyl D-dimethylaminobenzoate, isopropyl p-diethylaminobenzoate, Peroxides such as benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, cumene hydroperoxide, 9-phenylacridine, 9-p-methoxyphenylacridine, 9-acetylaminoacridine, benzacridine, etc. Acridine derivatives, phenazine derivatives such as 9,10-dimethylbenzphenazine, 9-methylbenzphenazine, 10-methoxybenzphenazine, and 6,4 ′, 4 ″ -trimethoxy-2,3-diphenylquinoxaline Quinoxaline derivatives, 2,4,5-triphenylimidazolyl dimer, 2-nitrofluorene, 2,4,6-triphenylpyrylium tetrafluoride boron salt, 2,4,6-tris (trichloromethyl) ) -1,3,5-triazine, 3,3′-carbonylbiscoumarin, thiomichler ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, oligo (2-hydroxy-2-methyl-1- ( 4- (1-methylvinyl) phenyl) propanone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, and the like.

  Moreover, when forming A layer by this invention, in order to prevent the fall of the sensitivity of the said initiator by oxygen inhibition, you may coexist an amine compound with a photoinitiator. Such an amine compound is not particularly limited as long as it is a non-volatile compound such as an aliphatic amine compound or an aromatic amine compound. For example, triethanolamine, methyldiethanolamine and the like are suitable.

  The conductive component that is preferably contained in the layer A is effectively used within the range of no problem, such as conductive oxide fine particles, inorganic salt chelates, and organic salts, but has low humidity dependency and processing conditions. It is preferable to use conductive oxide fine particles from the viewpoint of small fluctuation due to the above.

  In the present invention, the conductive particles refer to metal fine particles or conductive metal oxide fine particles. Among these, metal oxide fine particles are preferable because of their high transparency. As the metal oxide fine particles, tin-containing antimony oxide particles (ATO), zinc-containing antimony oxide particles, tin-containing indium oxide particles (ITO), zinc oxide / aluminum oxide particles, antimony oxide particles, and the like are particularly preferable, and tin-containing particles are more preferable. Indium oxide particles (ITO) and tin-containing antimony oxide particles (ATO).

  As the particles constituting the conductivity, particles having an average particle diameter (sphere equivalent diameter measured by the BET method shown in JIS R1626 (defined in JIS Z8819-1)) of 0.5 μm or less are preferably used. However, a particle diameter of 0.001 to 0.3 μm, more preferably 0.005 to 0.2 μm is used. When the average particle diameter exceeds this range, the transparency of the coating film (A layer) is reduced. When the average particle diameter is less than this range, the particles tend to aggregate and the haze value of the generated coating film (A layer) increases. In either case, it becomes difficult to obtain a desired haze value.

  In the present invention, the constituent component of the layer A preferably has a mass ratio of 50% or less with respect to the particles. On the other hand, if the number of particles is too large, various physical and chemical strengths of the resulting film are deteriorated, haze value is increased, and transparency is lowered. The quantity of a photoinitiator is 0.1-20 mass parts normally with respect to 100 mass parts of binder components (A), Preferably it is added in 1.0-15.0 mass parts. If it is less than 0.1 parts by mass, photopolymerization is slow, and it tends to require long-time light irradiation in order to satisfy hardness and scratch resistance, and sometimes tends to be uncured. On the other hand, when it exceeds 20 mass parts, functions, such as electroconductivity of a coating film, abrasion resistance, a weather resistance, will fall easily.

  The constituent components of the A layer of the present invention include the above-described resin components, particles, and photopolymerization initiator as essential constituent components, and further include, for example, a polymerization inhibitor, a curing catalyst, an antioxidant, and a dispersing agent. In the case of laminating the B layer on the A layer, the inclusion of the organic substituent-containing alkoxysilane compound improves the scratch resistance of the surface of the reflective film. preferable.

Examples of such organic substituent-containing alkoxysilane compounds include alkyl groups, fluoroalkyl groups, phenyl groups, vinyl groups, epoxy groups, styryl groups, methacryloxy groups, acryloxy groups, amino groups, ureido groups, chloropropyl groups, mercapto groups. Silane coupling agents having organic substituents such as sulfide groups, isocyanate groups, isocyanurate groups, etc., hydrolysates of these silane coupling agents, alkoxysilane compounds produced by condensation of the same or different silane coupling agents, Organic substituent-containing alkoxysilane compound obtained by condensing an organic silane-containing alkoxysilane compound comprising the above-mentioned silane coupling agent and an alkoxysilane compound not containing an organic substituent, and further containing an organic substituent reacted with various chlorosilanes, hydrosilanes, and silazanes. Alkoxy Lan compounds, mixed systems of these in any proportion, etc. are used, but are preferably used, but in particular, vinyl group, epoxy group, methacryloxy group, acryloxy group, amino group, ureido group, chloropropyl group, mercapto group, sulfide An alkoxysilane compound containing a group, an isocyanate group or the like is preferable from the viewpoint of reactivity, and an alkoxysilane compound having a kinematic viscosity of 5 mm ² / s (25 ° C.) or more is more preferable because of high reactivity per content.

  As content, it is preferable that it is 50 mass parts or less per 100 mass parts of resin components of A layer, when suppressing a raise of a surface resistance value, More preferably, it is 20 mass parts or less.

  In the present invention, the constituents of the A layer can further contain an organic metal compound such as a conductive polymer such as polypyrrole, polyaniline and polythiophene, a metal alcoholate and a chelate compound for the purpose of imparting conductivity. In addition, for the purpose of improving the surface hardness, the constituents of this A layer are alkyl silicates and hydrolysates thereof, colloidal silica, dry silica, wet silica, inorganic particles such as titanium oxide, and colloidally dispersed silica fine particles. Etc. can be further contained.

In order to provide a desired level of antistatic property by the A layer of the present invention, the surface resistivity of the A layer measured by the method shown in JIS K6911 should be 1 × 10 ¹² Ω / □ or less. More preferably, it is 1 × 10 ¹¹ Ω / □ or less.

  The layer A in the present invention is a layer having a total light transmittance of preferably 40% or more, more preferably 60% or more, from the viewpoint of sharpness and transparency.

  In the present invention, “... (Meta) acrylic ...” is an abbreviation of “... acrylic ... or meta acrylic ...”.

  In the present invention, the B layer has a refractive index lower than that of the A layer and is 1.42 or less. That is, when the refractive index is higher than that of the A layer, it does not function as an antireflection layer, and when the refractive index is higher than 1.42, both the maximum reflectance and the minimum reflectance of the surface reflection spectrum at a wavelength of 400 to 700 nm are increased. Antireflection performance is not obtained.

  In order to make the layer B have a refractive index of 1.42 or less, adopting a constitution mainly composed of a siloxane polymer combined with silica-based fine particles can reduce the refractive index and scratch resistance. From this point, it is preferably adopted. In other words, as the configuration in which the surface reflection spectrum at the wavelength of 400 to 700 nm according to the present invention satisfies the maximum reflectance and the minimum reflectance for satisfying all of the following three conditions, the conditions and configuration of the A layer are also included. In addition, it is particularly preferable to employ such a B layer configuration.

  The term “bond” as used herein means a state in which the silica component of the silica-based fine particles and the siloxane polymer in the matrix are reacted and homogenized.

  A siloxane polymer bonded to silica-based fine particles forms a silanol compound once by a known hydrolysis reaction with a polyfunctional silane compound in a solvent in the presence of the silica-based fine particles using an acid catalyst. It can be obtained by utilizing a condensation reaction.

  The polyfunctional silane compound preferably includes a polyfunctional fluorine-containing silane compound from the viewpoint of low refractive index and antifouling properties, and includes trifluoromethylmethoxysilane, trifluoromethylethoxysilane, and trifluoropropyltrimethoxy. Trifunctional fluorine-containing silane compounds such as silane, trifluoropropyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, Examples include bifunctional fluorine-containing silane compounds such as heptadecafluorodecylmethyldimethoxysilane, all of which are preferably used. From the viewpoint of surface hardness, trifluoromethylmethoxysilane, trifluoro Chill silane, trifluoropropyl trimethoxy silane, trifluoropropyl triethoxy silane, more preferably.

  Examples of such polyfunctional fluorine-free silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methyltrimethoxysilane, and methyltriethoxy. Silane, hexyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxy Trifunctional silanes such as silane, 3-chloropropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane, 3-glycidoxysipropyltrimethoxysilane Compound, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-amino Propylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylmethyldiethoxysilane, cyclohexylmethyldimethoxysilane, 3-methacryloxypropyldimethoxy Bifunctional silane compounds such as silane and octadecylmethyldimethoxysilane, tetrafunctional silane compounds such as tetramethoxysilane and tetraethoxysilane, etc. All of these are preferably used. From the viewpoint of surface hardness, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane are preferable. More preferable.

  Further, the silica fine particles are preferably silica-based fine particles having an average particle diameter of 1 nm to 200 nm, and particularly preferably an average particle diameter of 1 nm to 70 nm. When the average particle diameter is less than 1 nm, the bond with the matrix material becomes insufficient and the hardness may be lowered. On the other hand, if the average particle diameter exceeds 200 nm, the generation of voids between particles caused by introducing a large amount of particles is reduced, and the effect of lowering the refractive index may not be sufficiently exhibited. Further, among these silica-based fine particles, those having a structure having a cavity inside are particularly preferably used in order to lower the refractive index.

  Examples of such silica-based fine particles having cavities therein include silica-based fine particles having a hollow portion surrounded by an outer shell, porous silica-based fine particles having a large number of hollow portions, and the like. As such an example, for example, it can be produced by the method disclosed in Japanese Patent No. 3272111, and the volume occupied by the cavities inside the fine particles, that is, the porosity of the fine particles is preferably 5% or more, more preferably 30% or more. preferable. Further, the refractive index of the fine particles themselves is preferably 1.20 to 1.40, more preferably 1.20 to 1.35. Although a method of measuring the refractive index is described later, it can also be measured by a method disclosed in Japanese Patent Laid-Open No. 2001-233611. Examples of such silica-based fine particles include those disclosed in Japanese Patent Application Laid-Open No. 2001-233611, and those commercially available such as Japanese Patent No. 3272111.

  Acid catalysts used for the hydrolysis reaction include acid catalysts such as formic acid, oxalic acid, hydrochloric acid, sulfuric acid, acetic acid, trifluoroacetic acid, phosphoric acid, polyphosphoric acid, polyvalent carboxylic acid or anhydrides thereof, and ion exchange resins. It is done. In particular, formic acid and acetic acid are preferably used as catalysts from the viewpoint of improving the hardness of the transparent coating.

  A preferable addition amount is preferably 0.05% by mass to 10% by mass, and particularly preferably 0.1% by mass to 5% by mass with respect to the total silane compound content used in the synthesis of the siloxane polymer. If the amount of the acid catalyst is less than 0.05% by mass, the hydrolysis reaction may not proceed sufficiently. Moreover, when it exceeds 10 mass%, there exists a possibility that a hydrolysis reaction may run away.

  In the hydrolysis reaction, it is preferable to perform the reaction in a solvent because the control of the reaction is easy, and the solvent used is preferably an organic solvent. For example, alcohols such as ethanol, propanol, butanol, 3-methyl-3-methoxy-1-butanol; glycols such as ethylene glycol, propylene glycol; ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, diethyl Ethers such as ether; ketones such as methyl isobutyl ketone and diisobutyl ketone; amides such as dimethylformamide and dimethylacetamide; acetates such as ethyl acetate, ethyl cellosolve acetate, 3-methyl-3-methoxy-1-butanol acetate ; In addition to aromatic or aliphatic hydrocarbons such as toluene, xylene, hexane, cyclohexane, γ-butyrolactone, N-methyl 2-pyrrolidone, dimethyl sulfoxide and the like. The amount of the solvent is preferably added in the range of 50% by mass to 500% by mass, particularly preferably in the range of 80% by mass to 200% by mass, with respect to the total silane compound content used during the synthesis of the siloxane polymer. is there. If it is less than 50% by mass, the reaction may run away and gel. On the other hand, if it exceeds 500 mass%, hydrolysis may not proceed.

  Moreover, as water used for a hydrolysis, ion-exchange water is preferable. The amount of water can be arbitrarily selected, but it is preferably used in the range of 1.0 to 4.0 mol with respect to 1 mol of silane.

  The hydrolysis reaction is preferably performed at room temperature to 55 ° C by adding the acid catalyst and water in the solvent to the silane compound.

  As the conditions for the condensation reaction for obtaining the siloxane polymer of the present invention, it is preferable to carry out the reaction under reflux for 1 to 100 hours after hydrolysis to obtain a silanol compound. In addition, in order to increase the degree of polymerization of the siloxane polymer, it is possible to reheat or add a base catalyst.

In the optical film of the present invention, as described above, the refractive index and the thickness of the A layer are 1.62 or less and 0.3 μm or more, respectively. It is preferable that the wavelength is 1/4 of the wavelength of visible light. Accordingly, in the B layer, it is preferable that the product of the thickness d and the refractive index n of each layer is four times in the wavelength range of 400 to 700 nm. The relationship between the refractive index n and the thickness d in the B layer is expressed by the following formula ( The minimum reflectance of the surface reflection spectrum at a wavelength of 400 to 700 nm is 0.6% or more and 2.0% or less, and the maximum reflectance is 3.5% or less. In addition, it is preferable for the difference between the maximum reflectance and the minimum reflectance to be 2.5% or less.
n · d = λ / 4 Formula (1)
(Here, λ is the wavelength range of visible light and is usually in the range of 380 nm ≦ λ ≦ 780 nm).

  The layer B of the present invention preferably has a low surface energy from the viewpoint of antifouling properties and scratch resistance. For this purpose, the contact angle of the layer B is preferably 90 ° or more, and further the contact angle is 100 ° or more. It is preferable that In order to reduce the surface energy of the B layer, the atomic ratio F / Si between the F element and the Si element on the surface of the B layer is 0.5 to 5.0, and more preferably 0.7 to 3.0. From the viewpoint of scratch resistance and antifouling property. The atomic ratio can be obtained by Electron Spectroscopy for Chemical Analysis (ESCA analysis).

  As a method of providing the A layer and the B layer, any method such as a method of directly laminating on a base film by coating or a method of laminating a layer formed on another base material on a base film by transfer may be used. However, it is preferable to employ a method of directly laminating on a base film by coating from the viewpoint of production stability at an appropriate film thickness and cost.

  Examples of the coating method include various coating methods such as reverse coating method, gravure coating method, rod coating method, bar coating method, die coating method, spray coating method, and the like. In forming the layer, a reverse coating method, particularly a reverse coating using a small-diameter gravure roll is preferable from the viewpoint of coating accuracy.

  In addition, when applying the A layer and the B layer, it is preferable to prepare a coating solution in which the above components are dispersed in a solvent, and apply, dry and cure, and such a solvent improves coating or printing workability. Conventionally known various organic solvents can be used as long as they are blended in and dissolve the resin component. In particular, in the present invention, an organic solvent having a boiling point of 60 to 180 ° C. is preferable from the viewpoints of viscosity stability and drying property of the composition. Specific examples of such organic solvents include methanol, ethanol, isopropyl alcohol, n-butanol, tert-butanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, propylene glycol monomethyl ether, propylene glycol mono Preferable examples include ethyl ether, cyclohexanone, butyl acetate, isopropyl acetone, methyl ethyl ketone, methyl isobutyl ketone, diacetyl acetone, acetyl acetone and the like. These may be used alone or in combination of two or more.

  When preparing the coating solution used for forming the A layer, the amount of the organic solvent may be blended in an arbitrary amount so that the composition has a viscosity with good workability according to the coating means and the printing means. Usually, the solid content concentration of the composition is 60% by mass or less, preferably 50% by mass or less. As the preparation of the composition for forming a photocurable film of the present invention, any method can be adopted, but conductive particles are usually added to a solution in which a resin component is dissolved in an organic solvent, a paint shaker, A method of dispersing by a dispersing machine such as a ball mill, sand mill, three rolls, attritor, homomixer, etc., and then adding a photopolymerization initiator and dissolving it uniformly is suitable. Furthermore, when adding additives, such as the said alkoxysilane compound, adding immediately before application | coating is preferable.

  Examples of the actinic rays used in the present invention include electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams, and radiation (α rays, β rays, γ rays, etc.). It is preferable. As the ultraviolet ray source, an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a xenon lamp, a carbon arc lamp, or the like can be used. Moreover, when irradiating actinic radiation, if it irradiates under a low oxygen concentration, it can harden | cure efficiently.

  The coating solution used for forming the B layer of the present invention is preferably composed of the siloxane polymer as a main component, added with a curing agent, etc. and diluted with a solvent, and the content of the solvent is the total silane compound used during the synthesis of the siloxane polymer. It is preferable to add in the range of 1300 mass%-9900 mass% with respect to content, Most preferably, it is the range of 1500 mass%-6000 mass%. If the amount is less than 1300% by mass and exceeds 9900% by mass, it becomes difficult to form a transparent film having a predetermined film thickness.

  Examples of the curing agent include titanium, zirconium, aluminum, and magnesium. Among these, for the purpose of lowering the refractive index, aluminum-based and magnesium-based curing agents having a low refractive index are preferable. These curing agents can be easily obtained by reacting a metal alkoxide with a chelating agent. Examples of chelating agents include β-diketones such as acetylacetone, benzoylacetone, and dibenzoylmethane; β-keto acid esters such as ethyl acetoacetate and ethyl benzoylacetate.

  Preferable specific examples of the metal group chelate compound include ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetate bis (ethyl acetoacetate), aluminum tris Aluminum chelate compounds such as (acetylacetonate), magnesium chelate compounds such as ethyl acetoacetate magnesium monoisopropylate, magnesium bis (ethylacetoacetate), alkyl acetoacetate magnesium monosopropylate, magnesium bis (acetylacetonate) It is done. Of these, aluminum tris (acetylacetonate), aluminum tris (ethyl acetoacetate), magnesium bis (acetylacetonate), and magnesium bis (ethyl acetoacetate) are preferable, considering storage stability and availability. Then, aluminum tris (acetylacetonate) and aluminum tris (ethylacetoacetate) are particularly preferable. The amount of the metal chelate compound added is preferably 0.1% by mass to 10% by mass, particularly preferably 1% by mass to 6% by mass, based on the total silane compound content used during the synthesis of the siloxane polymer. %. When the amount introduced is less than 0.1% by mass, curing becomes insufficient, and when a transparent film is formed, the hardness decreases. On the other hand, when it exceeds 10% by mass, the curing becomes sufficient and the hardness of the transparent film is improved, but the refractive index is also improved, which is not preferable.

  In the present invention, after the B layer is cured, a protective film is preferably bonded to prevent the antireflection layer from being scratched or adhering to dust or the like.

  Such a protective film is not particularly limited, but a film having a 90-degree peel strength with the B layer in the range of 100 to 3000 mN / 25 mm is preferable, and a commercially available protective film can be used. Specific examples include “Sanitekte” manufactured by Sanae Kaken, “Hidalex” manufactured by Hitachi Chemical, and “Tretech” manufactured by Toray Film Processing Co., Ltd.

  The optical film of the present invention is formed by laminating a C layer on the surface of the base film opposite to the surface on which the A layer and the B layer are laminated.

  The C layer of the present invention is a laminated film made of a composition in which a pigment having near infrared absorption ability is dispersed in a transparent polymer resin binder. (4) The transmittance at a wavelength of 820 nm is 20% or less, and (5) the wavelength is 850 nm. The following three conditions are satisfied: (1) the transmittance at a wavelength of 950 nm to 1150 nm is 10% or less. Further, the transmittance at a wavelength of 820 nm is more preferably 17% or less, the transmittance at a wavelength of 850 nm is more preferably 11% or less, and the transmittance from a wavelength of 950 nm to 1150 nm is more preferably 7% or less.

  As such a near-infrared absorbing dye, a diimonium compound as disclosed in Japanese Patent Publication No. 43-25335 is preferable, and specifically, “KAYASORB” manufactured by Nippon Kayaku Co., Ltd. is used as the title. “IRG-022”, “IRG-023”, “IRG-050”, “IRG-068”, and the like.

The diimonium-based compound has a wide effective absorption wavelength region in the near infrared region with a wavelength of 850 to 1250 nm, and in order to reduce the transmittance at a wavelength of 950 nm to 1150 nm to 10% or less, the compound per unit area of the C layer The content is preferably 0.1 to 0.5 g / m ^2, and more preferably 0.2 to 0.3 g / m ² . If the content is below this range, the near-infrared shielding ability is inferior, and if the content exceeds this range, the visible light transmittance is insufficient and the image becomes dark.

  As the near-infrared absorbing dye in the present invention, only the above-mentioned diimonium compound may be used. In order to reduce the transmittance at a wavelength of 820 nm to 20% or less and the transmittance at a wavelength of 850 nm to 15% or less. , The content needs to be increased, and the visible light transmittance may be insufficient. Therefore, in the present invention, it is preferable to use one or more near infrared absorbing dyes having an absorption maximum wavelength in the wavelength range of 800 nm to 900 nm together with the diimonium compound. Specifically, phthalocyanine compounds or naphthalocyanine compounds, cyanine compounds, dithiol nickel complex compounds having one or more substituents of primary and / or secondary amino groups, alkoxy groups, halogen groups such as fluorine Etc. Of these, fluorine-containing phthalocyanine compounds are preferably used from the viewpoint of light resistance and heat and humidity resistance. Specific examples include “IR-1”, “IR-10”, “IR-12”, “IR-14” and the like, which are named “EEX Color” manufactured by Nippon Shokubai Co., Ltd.

  Further, although cyanine compounds have difficulty in light resistance, as an improved dye, a dye obtained by coupling a cyanine compound and a quencher in advance to be integrated is preferably used in the present invention. Here, the quencher agent refers to an antioxidant for a near-infrared absorbing dye. By integrating, the light resistance of the cyanine compound can be improved and a high extinction coefficient characteristic of the cyanine dye can be obtained, so that the amount of the dye used can be reduced. As the quencher, bis (1,2-dithiophenolate) copper tetra-n-butylammonium salt is preferable because it does not impair the light resistance of the diimonium compound. Specific examples of the integrated dye of the cyanine compound and the quencher include “SD50-E04N” and “SD50-E05N” manufactured by Sumitomo Seika Co., Ltd. and “TZ-111” manufactured by Asahi Denka Kogyo Co., Ltd. , “TZ-114”, “TZ-118” and the like.

The content per unit area of the near-infrared absorbing dye compound having an absorption maximum wavelength in the wavelength range of 800 nm to 900 nm is determined according to the extinction coefficient of the dye used and the content of the diimonium compound, but the wavelength is 820 nm. In order to reduce the transmittance at 20% or less and the transmittance at a wavelength of 850 nm to 15% or less, the content is preferably 0.01 to 0.3 g / m ^2. In the case of using an integrated dye with a char agent, it is preferably 0.01 to 0.1 g / m ² . If the content is below this range, the near-infrared shielding ability is inferior, and if the content exceeds this range, the visible light transmittance is insufficient and the image becomes dark.

  The transparent polymer resin binder used in the present invention is substantially colorless and transparent with no visible light absorption, such as polyester resin, (meth) acrylic resin, (meth) acrylic urethane resin, polycarbonate resin, etc. Of these, (meth) acrylic resins are preferred.

  Such (meth) acrylic resins are methyl (meth) acrylate, ethyl (meth) acrylate, n- or isopropyl (meth) acrylate, n- or sec- or tert-butyl (meth) acrylate, pentyl (meth) acrylate. , Hexyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) ) Acrylate, hydroxyethyl (meth) acrylate, (meth) acrylic acid, itaconic acid, maleic anhydride, glycidyl (meth) acrylate, fluorine-containing (meth) acrylate, styrene Those obtained by copolymerizing an unsaturated monomer classes are preferred. Furthermore, in order to improve the light resistance of the near-infrared absorbing dye, an unsaturated monomer having a hindered amine which is an ultraviolet light-stable group (for example, Adeka Stub LA-82, LA-87, etc. manufactured by Asahi Denka Kogyo Co., Ltd.), benzo A copolymer obtained by copolymerizing an unsaturated monomer having an ultraviolet absorbing group such as triazole, benzophenone, or triazine is used, or a hindered amine additive (for example, Sanol LS-765, LS- manufactured by Sankyo Lifetech Co., Ltd.). 2626) or an ultraviolet absorber is preferably added to the polymerized resin.

  The (meth) acrylic resin preferably has a glass transition point of 80 ° C. or more from the viewpoint of heat resistance, but is not limited thereto. In order to reduce the influence of moisture on the near-infrared absorbing pigment, the hygroscopicity of the resin is preferably 2% or less.

  Furthermore, the (meth) acrylic resin may be crosslinked to improve solvent resistance. In this case, a crosslinking agent such as aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate, or melamine is preferably used. . Further, a silane coupling agent may be added in order to improve the adhesion with the easy adhesion layer. Examples of such silane coupling agents include alkoxysilane compounds having an unsaturated group or an epoxy group.

  The (meth) acrylic resin is preferably soluble in an organic solvent, particularly those that are soluble in methyl ethyl ketone, methyl butyl ketone, cyclohexanone, acetone, acetonitrile, ethyl acetate, butyl acetate, toluene, xylene and the like. These are used alone or as a mixed solvent of two or more. The viscosity of the (meth) acrylic resin is 50 to 5000 mPa.s in consideration of workability when preparing a paint by preparing a near infrared absorbing dye compound. It is preferable that it is s, and it is preferable that the solid content density | concentration of (meth) acrylic-type resin is 10-50 mass%.

  Specific examples of such (meth) acrylic resin binders include “Dianar BR-80” manufactured by Mitsubishi Rayon Co., Ltd. and “Hals Hybrid IR-G205” manufactured by Nippon Shokubai Co., Ltd.

  In the C layer of the present invention, color tone correction is performed by mixing a transparent polymer resin binder with a near-infrared absorbing dye and a dye that selectively absorbs visible light near a wavelength of 590 nm, which reduces the red purity associated with the emission of neon gas. It is preferable to have a function. In that case, the C layer contains a dye having a main absorption peak in the wavelength range of 570 to 610 nm and a half width of the main absorption peak of 50 nm or less, and the transmittance at a wavelength of 590 nm is 35% or less, more preferably It is preferable that it is 32% or less and the total light transmittance is 55% or more, more preferably 60% or more. The transmittance at a wavelength of 590 nm is preferably low, but if it is too low, the total light transmittance is also low, so it is preferably 25% or more.

As the dye used for color tone correction, for example, a porphyrazine-based compound (also known as a tetraazaporphyrin compound) as disclosed in JP-A No. 2002-129052 has light resistance, solubility in an organic solvent, and an extinction coefficient. Are preferably used. Specific examples include “TAP-2” manufactured by Yamada Chemical Co., Ltd. The content of porphyrazine compound per unit area of the C layer is preferably from 0.03~0.07g / ^{m 2,} more and more preferably, 0.04~0.06g / ^{m 2.} If the content is less than this range, the color tone correcting ability is inferior, and if the content exceeds this range, the visible light transmittance is insufficient and the image becomes dark.

  The above near-infrared absorbing pigment and color tone correcting pigment can be either dyes or pigments, but it is preferable to use a dye in consideration of transparency and transmittance of visible light. In the case of using a dye, one that dissolves in an organic solvent in which the polymer resin binder is soluble is preferable. Examples of the organic solvent include methyl ethyl ketone, methyl butyl ketone, cyclohexanone, acetone, acetonitrile, ethyl acetate, butyl acetate, toluene, xylene and the like.

  The near-infrared absorbing dye and the color tone correcting dye are used after being dissolved in the organic solvent and then mixed with a polymer resin binder solution or an organic solvent to form a paint. Furthermore, it is also preferable to mix | blend a ultraviolet absorber, a ultraviolet stabilizer, antioxidant, a leveling agent, an antifoamer, etc. with a coating material.

  The paint is applied on the easy-adhesion layer of the base film by a known coating method such as three reverse coaters, normal rotation or reverse gravure coater, comma coater, die coater, etc., and dried in an oven to form a film. , C layer is formed.

  The thickness of the C layer of the present invention is not particularly limited, but is preferably 3 to 30 μm, and more preferably 4 to 15 μm from the viewpoint of the coating property of the (meth) acrylic resin binder on the film. is there.

  In order to bond the optical film of the present invention and other optical filter elements such as semi-tempered glass or electromagnetic wave shielding film, a transparent adhesive layer is laminated on the C layer, and the other until the bonding process. It is preferable that a release film is laminated to prevent adhesion with the surface.

  The transparent adhesive layer in the present invention is not particularly limited as long as it can adhere two objects by their adhesive action. As the pressure-sensitive adhesive forming the transparent pressure-sensitive adhesive layer, rubber-based, vinyl polymerization-based, condensation polymerization-based, thermosetting resin-based, silicone-based, and the like can be used. Among these, examples of the rubber-based adhesive include butadiene-styrene copolymer system (SBR), butadiene-acrylonitrile copolymer system (NBR), chloroprene polymer system, and isobutylene-isoprene copolymer system (butyl rubber). it can. Examples of the vinyl polymerization-based pressure-sensitive adhesive include acrylic resin-based, styrene resin-based, vinyl acetate-ethylene copolymer system, and vinyl chloride-vinyl acetate copolymer system. Examples of the condensation polymerization pressure-sensitive adhesive include a polyester resin system. Examples of the thermosetting resin adhesive include epoxy resin, urethane resin, formalin resin, and the like. These resins may be used alone or in combination of two or more. Further, the transparent pressure-sensitive adhesive can be either a solvent-type pressure-sensitive adhesive or a solventless pressure-sensitive adhesive.

  The formation of the transparent adhesive layer is carried out using a conventional technique such as coating, using the above-mentioned adhesive. Furthermore, you may make a transparent adhesive layer contain a coloring agent. This is easily achieved by mixing and using a colorant such as an organic pigment or organic dye in the adhesive. From the viewpoint of durability, it is preferable to use an organic pigment, but it is preferable to use an organic dye in terms of dispersibility in an adhesive and color development. These colorants are used for final color matching of the optical film. The transmitted color of the optical film of the present invention is not particularly limited, but preferably the chromaticity x is 0.27 to 0.34 and y is preferably 0.27 to 0.34.

  In the present invention, the transparent adhesive layer is made by wiping and drying the glass plate surface with an absorbent cotton impregnated with ethanol, and then peeling off the release film of the film sample (25 mm width strip) on which the transparent adhesive layer has been laminated. The film peel strength at 90 degrees measured by a tensile tester is preferably in the range of 5 to 25 N / 25 mm after being left for 24 hours under the conditions of 23 ° C. and 65% RH, and more preferably 10 to 20 N. A range of / 25 mm is preferred. If it is lower than this, the adhesive strength is weak and it is easy to peel off. On the contrary, if it is strong, the resin tends to be hard, which is not preferable. The thickness of the transparent adhesive layer is preferably 10 to 50 μm, more preferably 20 to 30 μm.

  Furthermore, the transparent adhesive layer is bonded to the release film in consideration of workability until it is actually bonded to the semi-tempered glass or the electromagnetic wave shielding film. As the release film, a film in which a release agent such as silicone is coated on a film substrate such as polyester is suitably used.

  The peel strength of the release film of the present invention at 90 degrees with the transparent adhesive layer is preferably in the range of 10 to 100 mN / 25 mm, and more preferably in the range of 30 to 70 mN / 25 mm. It is done. Specific examples of the release film include “Therapel” manufactured by Toray Film Processing Co., Ltd.

  The transparent adhesive layer of the present invention is applied to the release surface of the release film by a coating method such as three reverse coaters, forward rotation or reverse gravure coater, comma coater, die coater, etc., and dried in an oven. After the film formation, a method of laminating by laminating with the C layer of the optical film is preferable, but it is not limited to this method.

  The optical film of the present invention has low surface reflectance, excellent surface scratch resistance, and at the same time has excellent near-infrared shielding ability and color tone correction ability, so that an electromagnetic shielding film, an impact absorbing layer, semi-tempered glass, etc. In combination, it is suitably used for an optical filter of a plasma display panel (PDP). Furthermore, by integrating the functions in this way, it is possible to improve the productivity of the optical filter and contribute to the cost reduction by omitting the number of parts and the bonding process.

[Characteristic measurement method and effect evaluation method]
The characteristic measurement method and effect evaluation method in the present invention are defined as follows.

(1) Steel wool hardness (abrasion resistance evaluation)
Scratch resistance is determined by applying a load of 250 g to # 0000 steel wool on the surface of the antireflection layer, rubbing it 10 times at a stroke width of 10 cm and a speed of 30 mm / sec, and then visually observing the surface to determine how the scratches are attached. Evaluation was made in the following five stages.
5th grade: No scratches.
Fourth grade: 1 to 5 scratches.
3rd grade: 6 to 10 scratches.
Second grade: 11 or more scratches.
First grade: Countless scratches on the entire surface.

(2) Haze The haze of the film was measured using a turbidimeter (NDH2000) manufactured by Nippon Denshoku Industries Co., Ltd. based on JIS K7136.

(3) Surface resistance value (antistatic evaluation)
The film was sampled into a square of 100 mm × 100 mm, the antireflection layer surface was pretreated by the method shown in JIS K6911, and the surface was used using HIRESTA UP (MCP-HT450: conforming to JIS K6911) manufactured by Mitsubishi Yuka Co., Ltd. The resistance value was measured.

(4) Reflectance (antireflection performance evaluation)
After the surface opposite to the measurement surface (surface on which the antireflection layer is provided) is uniformly roughened with a 320-400 water resistant sandpaper so that the 60 ° C. gloss (JIS Z 8741) is 10 or less. The black paint was applied and colored so that the visible light transmittance was 5% or less. Using a spectrophotometer (UV-3150) manufactured by Shimadzu Corporation, the absolute reflection spectrum in the wavelength region of 380 nm to 800 nm was measured at an incident angle of 5 degrees from the measurement surface, and the reflectance at wavelengths of 400 nm and 700 nm The minimum reflectance in the region of 400 nm to 700 nm was determined. When the measured reflection spectrum has undulations, the respective reflectances were obtained from curves connecting intermediate points between undulation peaks (maximum points) and valleys (minimum points).

(5) Transmittance of specific wavelength (near infrared shielding performance and color correction performance evaluation)
The transmission spectrum of the optical film was measured in the wavelength range of 380 to 1200 nm with a spectrophotometer (U-3410) manufactured by Shimadzu Corporation. As specific wavelengths among them, transmittances of 590 nm, 820 nm, and 850 nm and a maximum transmittance in a range of 950 to 1150 nm were obtained.

(6) Total light transmittance The total light transmittance of the optical film was measured using a turbidimeter manufactured by Nippon Denshoku Industries Co., Ltd. (NDH2000) based on JIS K7361-1.

(7) Transmission chromaticity coordinates (colorimetric evaluation)
Using an SM color computer (SM-6) manufactured by Suga Test Instruments Co., Ltd., the XYZ stimulation value of the optical film was measured in a C light source 2 ° field of view, and transmission chromaticity coordinates (x, y) were determined.

(8) Normal adhesion evaluation Under normal conditions (23 ° C., relative humidity 65% RH), 100 pieces of 1 mm ² crosscuts were put on the C layer, and cellophane tape made by Nichiban Co., Ltd. was pasted on the rubber roller. Was reciprocated three times with a load of 19.6 N, pressed, peeled off in the direction of 90 degrees, and evaluated in four stages according to the number of remaining C layers (A: 100, B: 80 to 99, C: 50 to 79, D : 0-49). (A) and (B) were considered to have good adhesion.

(9) Light resistance evaluation Using an ultraviolet fade meter (FAL-3) manufactured by Suga Test Instruments Co., Ltd., the optical film was irradiated with ultraviolet rays at 63 ± 3 ° C. for 24 hours. Measure the transmission spectrum of the optical film, and pass all the specific wavelengths listed in (5) with a transmittance difference of less than 1% before and after UV irradiation. When it was 1% or more, it was determined as rejected (x).

(10) Moisture and heat resistance evaluation An optical film was placed in a thermostatic chamber at a temperature of 60 ° C. and 90% RH for 500 hours. The transmission spectrum of the optical film is measured, and the transmittance difference before and after the wet and heat resistance evaluation of all the specific wavelengths listed in (5) is less than 1%. When it was 1% or more, it was determined as rejected (x).

  Next, although this invention is demonstrated based on an Example, this invention is not necessarily limited to these.

(Preparation of organic substituent-containing alkoxysilane compound)
138 parts by mass of methyltrimethoxysilane, 236 parts by mass of 3-glycidoxypropyltrimethoxysilane and 120 parts by mass of isopropyl alcohol were mixed with stirring, and 1.7 parts by mass of formic acid and 72 parts by mass of water were blended, Hydrolyze with stirring at 10 ° C for 30 minutes, further raise the temperature to 80 ° C ± 5 ° C, polymerize with stirring for 60 minutes, cool to room temperature, and then distill off the solvent to remove methyl group and epoxy group-containing alkoxysilane A compound was obtained. The kinematic viscosity was 45 mm ² / s at 25 ° C.

(Preparation of layer B paint-1)
A silica slurry comprising 144 parts by mass of hollow silica particles having an outer shell with a primary particle diameter of 50 nm (porosity 40%) and 560 parts by mass of isopropyl alcohol was prepared, 219 parts by mass of methyltrimethoxysilane, 3,3,3-tri 158 parts by mass of fluoropropyltrimethoxysilane, 704 parts by mass of the above silica slurry, and 713 parts by mass of polypropylene glycol monoethyl ether are mixed with stirring, 1 part by mass of phosphoric acid and 130 parts by mass of water are mixed, and the mixture is stirred at 30 ° C. ± 10 ° C. Then, the mixture was hydrolyzed for 60 minutes, and the temperature was raised to 80 ° C. ± 5 ° C., followed by polymerization while stirring for 60 minutes to obtain a silica particle-containing polymer.

  Next, 1200 parts by mass of this silica particle-containing polymer and 5244 parts by mass of isopropyl alcohol were stirred and mixed, then 15 parts by mass of acetoxyaluminum as a curing catalyst was added and stirred again to prepare a paint having a refractive index of 1.35. .

(Preparation of layer B paint-2)
Silica fine particle sol (trade name: IPA-ST, manufactured by Nissan Chemical Industries, Ltd., solid content: 30%) dispersed in isopropyl alcohol having a particle diameter of 12 nm and having no cavities, has a primary particle diameter of 50 nm. In the same manner as in the preparation of the layer B paint-1, except that the silica slurry is made of 144 parts by mass of hollow silica particles (porosity 40%) and 560 parts by mass of isopropyl alcohol. A particle-containing polymer was obtained.

  Next, after 1200 parts by mass of this silica particle-containing polymer and 5466 parts by mass of isopropyl alcohol were mixed with stirring, 15 parts by mass of acetoxyaluminum was added as a curing catalyst and mixed again with stirring to prepare a paint having a refractive index of 1.38. .

(Adjustment of C layer paint-1)
As a near-infrared absorbing dye, 29 parts by mass of “KAYASORB IRG-050” manufactured by Nippon Kayaku Co., Ltd., and 16 parts by mass of “eXcolor IR-10A” manufactured by Nippon Shokubai Co., Ltd. were mixed with 2000 parts by mass of methyl ethyl ketone. And dissolved. This solution was used as a transparent polymer resin binder solution, and was stirred and mixed with 2000 parts by mass of “Hals Hybrid IR-G205” (solid content 29% solution) manufactured by Nippon Shokubai Co., Ltd. to prepare a near-infrared shielding coating-1.

(Adjustment of C layer paint-2)
As a near-infrared absorbing dye, 29 parts by mass of “KAYASORB IRG-023” manufactured by Nippon Kayaku Co., Ltd., 3 parts by mass of “TZ-111” manufactured by Asahi Denka Kogyo Co., Ltd., and 3 parts by mass of “TZ-114” Part was stirred and mixed with 2000 parts by mass of methyl ethyl ketone and dissolved. This solution was used as a transparent polymer resin binder solution, and was stirred and mixed with 2000 parts by mass of “Hals Hybrid IR-G205” (solid content 29% solution) manufactured by Nippon Shokubai Co., Ltd. to prepare a near-infrared shielding paint-2.

(Adjustment of C layer paint-3)
As a near-infrared absorbing dye, 29 parts by mass of “KAYASORB IRG-050” manufactured by Nippon Kayaku Co., Ltd., 16 parts by mass of “EEX Color IR-10A” manufactured by Nippon Shokubai Co., Ltd. “TAP-2” manufactured by Yamada Chemical Co., Ltd. was dissolved by mixing 5.8 parts by mass with 2000 parts by mass of methyl ethyl ketone. This solution was used as a transparent polymer resin binder solution, and was stirred and mixed with 2000 parts by mass of “Hals Hybrid IR-G205” (solid content concentration 29% solution) manufactured by Nippon Shokubai Co., Ltd. to prepare a near infrared shielding coating-3.

(Adjustment of C layer paint-4)
As a near-infrared absorbing dye, 29 parts by mass of “KAYASORB IRG-050” manufactured by Nippon Kayaku Co., Ltd., 3 parts by mass of “TZ-111” manufactured by Asahi Denka Kogyo Co., Ltd., and 3 mass of “TZ-114” In addition, 5.8 parts by mass of “TAP-2” manufactured by Yamada Chemical Industry Co., Ltd. was mixed and dissolved in 2000 parts by mass of methyl ethyl ketone as a color correction pigment. This solution was used as a transparent polymer resin binder solution, and was stirred and mixed with 2000 parts by mass of “Hals Hybrid IR-G205” (solid content 29% solution) manufactured by Nippon Shokubai Co., Ltd. to prepare a near-infrared shielding paint-4.

Example 1
An antimony-containing tin oxide fine particle having an average particle diameter of about 10 nm and 25% by mass on the easy-adhesion surface side made of a polyester resin of a commercially available optically-adhesive polyester film (Lumirror (registered trademark) QT77 manufactured by Toray Industries Inc., thickness 100 μm) and multifunctional A coating solution containing acrylate (Seika Beam PET-AS-41: refractive index 1.53 manufactured by Dainichi Seika Co., Ltd.) and the organic substituent-containing alkoxysilane compound are mixed at a mass ratio of 33: 1 and the stirred coating solution is reduced in diameter. After coating with a gravure coater and drying at 90 ° C., it was cured by irradiation with ultraviolet rays of 400 mJ / cm ² to form an A layer having a thickness of about 3 μm. Next, on the A layer, the B layer paint-1 is applied with a small diameter gravure coater, dried and cured at 130 ° C. to form a B layer having a thickness of about 0.1 μm, and an antireflection layer is formed. Laminated. Table 1 shows the evaluation results of the scratch resistance, haze, and surface resistance of the film (so-called antireflection film) at this stage. The scratch resistance was grade 4, the haze was as high as 0.3%, and the antistatic property was also good. Table 2 shows the maximum reflectance, the minimum reflectance, and the difference between the maximum reflectance and the minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm. Since the minimum reflectance was as low as 1.0% and the reflectance difference was 2.5% or less, the antireflection layer was neutral in color. Next, C layer paint-1 was applied using a die coater on the side opposite to the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77), dried at 120 ° C., and a thickness of 10 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, and the adhesion under normal conditions, light resistance, and heat and humidity resistance were excellent.

(Example 2)
For layer B, use a paint containing a fluorine-containing copolymer (fluoroolefin / vinyl ether copolymer) (manufactured by JSR Corporation, JN-7215: refractive index 1.42), and dry and cure at 150 ° C. Except for this, an antireflection layer was laminated in the same manner as in Example 1. The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). Since the minimum reflectance was as low as 1.6% and the reflectance difference was 2.5% or less, the antireflection layer was neutral in color. Next, C layer paint-1 was applied using a die coater on the side opposite to the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77), dried at 120 ° C., and a thickness of 10 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, and the adhesion under normal conditions, light resistance, and heat and humidity resistance were excellent.

(Example 3)
Regarding the B layer, an antireflection layer was laminated in the same manner as in Example 1 except that the B layer paint-2 was used.

  The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). Since the minimum reflectance was as low as 1.3% and the difference in reflectance was 2.5% or less, the antireflection layer was neutral in color. Next, C layer paint-1 was applied to the opposite side of the antireflection layer (the easy-adhesion side of the QT77 acrylic resin) using a die coater, dried at 120 ° C., and a thickness of 10 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, and the adhesion under normal conditions, light resistance, and heat and humidity resistance were excellent.

Example 4
For layer A, a paint containing polyfunctional acrylate (Desolite Z7528 manufactured by JSR: refractive index 1.50) and the organic substituent-containing alkoxysilane compound were mixed at a mass ratio of 20: 1, and a small-diameter gravure was used using a stirred coating solution. After coating with a coater and drying at 80 ° C., an antireflection layer was laminated in the same manner as in Example 1 except that an ultraviolet ray of 400 mJ / cm ² was applied and cured to provide an A layer having a thickness of about 3 μm. .

  The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). Since the minimum reflectance was as low as 1.1% and the reflectance difference was 2.5% or less, the antireflection layer was neutral in color. Next, on the side opposite to the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77), the C-layer paint-2 was applied using a die coater, dried at 120 ° C., and a thickness of 10 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, and the adhesion under normal conditions, light resistance, and heat and humidity resistance were excellent.

(Example 5)
For layer A, except that 20% by mass of antimony-containing tin oxide fine particles with a primary particle size of 30 nm and a paint containing polyfunctional acrylate (KAS-565M-30A: refractive index 1.53 manufactured by Nippon Kayaku Co., Ltd.) are used. The antireflection layer was laminated in the same manner as in Example 1.

  The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). Since the minimum reflectance was as low as 1.0% and the reflectance difference was 2.5% or less, the antireflection layer was neutral in color. Next, on the side opposite to the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77), the C-layer paint-2 was applied using a die coater, dried at 120 ° C., and a thickness of 10 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, and the adhesion under normal conditions, light resistance, and heat and humidity resistance were excellent.

(Example 6)
When preparing the layer A coating solution, an antireflection layer was laminated in the same manner as in Example 1 except that the organic substituent-containing alkoxysilane compound was not added.

  The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). Since the minimum reflectance was as low as 1.0% and the reflectance difference was 2.5% or less, the antireflection layer was neutral in color. Next, on the side opposite to the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77), the C-layer paint-2 was applied using a die coater, dried at 120 ° C., and a thickness of 10 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, and the adhesion under normal conditions, light resistance, and heat and humidity resistance were excellent.

(Example 7)
In Example 1, a C layer having a thickness of 10 μm was laminated in the same manner as in Example 1 except that the C layer paint was changed to the C layer paint-2. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, and the adhesion under normal conditions, light resistance, and heat and humidity resistance were excellent.

(Example 8)
In Example 1, a C layer having a thickness of 10 μm was laminated in the same manner as in Example 1 except that the C layer paint was changed to the C layer paint-3. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, the transmittance at 590 nm was 30%, and the total light transmittance was also 60.4%. Furthermore, it was excellent in adhesion under normal conditions, light resistance, and heat and humidity resistance.

Example 9
In Example 1, a C layer having a thickness of 10 μm was laminated in the same manner as in Example 1 except that the C layer paint was changed to the C layer paint-4. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm, 850 nm, and 950 to 1150 nm was good, the transmittance at 590 nm was 30%, and the total light transmittance was also good at 62.7%. Furthermore, it was excellent in adhesion under normal conditions, light resistance, and heat and humidity resistance.

(Comparative Example 1)
Regarding the A layer, an antireflection layer was laminated in the same manner as in Example 1 except that the film thickness was about 0.1 μm.

  The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). The minimum reflectance exceeded 2%, and the antireflection property was insufficient. Also, the scratch resistance was as low as first grade. Next, C layer paint-1 was applied to the surface opposite to the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77) using a die coater, dried at 120 ° C., and a thickness of 8 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittances at 820 nm and 850 nm are both high, and the near-infrared shielding property is not sufficient.

(Comparative Example 2)
For layer B, a silicone-based hard coat agent (AY-150 manufactured by Toray Dow Corning Silicone Co., Ltd .: refractive index 1.44) is used as a paint, dried at 80 ° C., and then irradiated with ultraviolet rays 400 mJ / cm ² to be cured. The antireflection layer was laminated in the same manner as in Example 1 except that a B layer having a thickness of about 0.1 μm was provided.

  The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). The minimum reflectance exceeded 2%, the maximum reflectance exceeded 3.5%, and the antireflection property was insufficient. Next, C layer paint-1 was applied to the opposite side of the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77) using a die coater, dried at 120 ° C., and a thickness of 5 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittances at 820 nm, 850 nm, and 950 to 1150 nm are all high, and the near infrared shielding property is not sufficient.

(Comparative Example 3)
For layer A, paint containing tin-containing indium oxide particles (ITO) (polyfunctional urethane (meth) acrylate / ITO particles (average primary particle size 30 nm) = 18/82) (Dainippon Paint Co., Ltd., EI-3 : An antireflection layer was laminated in the same manner as in Example 1 except that a refractive index of 1.65) was used.

  The evaluation results of the obtained antireflection film are shown in Table 1 (scratch resistance, haze, surface resistance value) and Table 2 (maximum reflectance, minimum reflectance, maximum reflectance and minimum reflectance at wavelengths of 400 to 700 nm and 500 to 700 nm). Reflectance difference). The haze was as high as 1.8% and the transparency was poor. Next, on the side opposite to the antireflection layer (the easy adhesion surface side made of an acrylic resin of QT77), C layer paint-2 was applied using a die coater, dried at 120 ° C., and a thickness of 8 μm. C layer was laminated. Table 3 shows the properties of the obtained optical film. The transmittance at 820 nm is high and the near infrared shielding property is not sufficient.

(Example 10)
“Kayset red” manufactured by Nippon Kayaku Co., Ltd. as a colorant is added to an adhesive prepared from 1000 parts by weight of “SK Dyne-1310” manufactured by Soken Chemical Co., Ltd., 33 parts by weight of curing agent “M5A” and 300 parts by weight of isopropyl alcohol. "Kayase violet" and "Kayase blue" were blended and applied to the release surface of a 75 μm thick release film (“Therapel” manufactured by Toray Film Processing Co., Ltd.) with a die coater and dried at 100 ° C. Then, it laminated with the C layer surface of the optical film obtained in Example 8. As for the transmission chromaticity of the obtained film, x was 0.292 and y was 0.294. Moreover, the obtained film was cut into a 25 mm width strip, the adhesive layer and the glass plate were bonded together, and a 90 degree peel test was performed. The adhesive strength with the glass plate was 15 N / 25 mm.

(Example 11)
A commercially available electromagnetic wave absorbing film (manufactured by Nippon Filcon Co., Ltd., pressure sensitive adhesive mesh type) was bonded to semi-tempered glass, and the optical film prepared in Example 10 was bonded thereon to prepare an optical filter for PDP. An optical filter having a color tone with little reflection and neutral reflection color was obtained.

  The optical film of the present invention has a low surface reflectance, a neutral color, excellent surface scratch resistance, and excellent near-infrared shielding ability and color tone correction ability, and is imparted with electromagnetic shielding ability. It is suitably used as an optical filter for PDP by being bonded to a glass plate. Alternatively, after the optical film of the present invention is bonded to the electromagnetic wave shielding film, it can be directly bonded to the front plate of the PDP via an impact absorbing adhesive layer.

It is the figure which represented typically the cross section which shows an example of the antireflection film of this invention.

Explanation of symbols

1: B layer 2: A layer 3: Base film 4: C layer 5: Antireflection layer

Claims (16)

A layer having a film thickness of 0.3 μm or more and a refractive index of 1.62 or less, and a B layer having a refractive index lower than that of the A layer and 1.42 or less on one surface of the base film At least two layers are laminated so that the A layer is closer to the base film than the B layer, and a dye having a near infrared absorbing ability is placed in a transparent polymer resin on the other surface of the base film. In the optical film in which the dispersed C layer is laminated, the surface reflection spectrum of the B layer at a wavelength of 400 to 700 nm satisfies all the following three conditions;
(1) The minimum reflectance is 0.6% or more and 2.0% or less.
(2) Maximum reflectance is 3.5% or less.
(3) The difference between the maximum reflectance and the minimum reflectance is 2.5% or less.
An optical film in which the C layer satisfies all of the following three conditions.
(4) The transmittance at a wavelength of 820 nm is 20% or less.
(5) The transmittance at a wavelength of 850 nm is 15% or less.
(6) The transmittance at wavelengths from 950 nm to 1150 nm is 10% or less. The optical film according to claim 1, wherein the C layer satisfies all of the following three conditions.
(7) A dye having a main absorption peak in the wavelength range of 570 to 610 nm and a half width of the main absorption peak of 50 nm or less is included.
(8) The transmittance at a wavelength of 590 nm is 35% or less.
(9) Total light transmittance is 55% or more.   The optical film according to claim 1 or 2, wherein the haze is 1.5% or less.   The optical film according to any one of claims 1 to 3, wherein the B layer is mainly composed of a siloxane polymer formed by bonding with silica-based fine particles.   The optical film according to claim 4, wherein the silica-based fine particles have a cavity inside.   The optical film according to claim 4, wherein the siloxane polymer contains a polyfunctional fluorine-containing silane compound.   The optical film according to claim 1, wherein the refractive index of the A layer is 1.48 or more and 1.62 or less.   The said A layer contains electroconductive metal oxide microparticles | fine-particles, and content of this electroconductive metal oxide microparticles | fine-particles is 50 mass% or less with respect to A layer. Optical film.   The optical film according to claim 1, wherein the B layer is laminated on the A layer.   The optical film according to claim 1, wherein the layer A contains an organic substituent-containing alkoxysilane compound.   The organic substituent-containing alkoxysilane compound is at least one selected from the group consisting of vinyl group, epoxy group, methacryloxy group, acryloxy group, amino group, ureido group, chloropropyl group, mercapto group, sulfide group, and isocyanate group. The optical film according to claim 10. The optical film according to claim 10, wherein the organic substituent-containing alkoxysilane compound is a condensate having a kinematic viscosity of 5 mm ² / s (25 ° C.) or more.   The optical film according to any one of claims 1 to 12, wherein the scratch resistance of the surface of the B layer is 3 or more (defined in the text). 14. The optical film according to claim 1, wherein the B layer has a surface resistance value of 1 × 10 ¹² Ω or less.   The optical film according to claim 1, wherein the base film is made of at least one selected from the group consisting of a polyester resin, an acetate resin, and an acrylic resin.   The optical filter for plasma display panels formed by bonding the optical film in any one of Claims 1-15.

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