JP2010099835A - Hard coat film containing ultraviolet absorber and optical filter for display equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat film which includes a transparent plastic film 12 and a hard coat layer 14 formed from an ultraviolet curing resin composition containing an ultraviolet absorber formed on one surface of the film 12 and has enough surface hardness and a sufficient ultraviolet absorption effect and in which curling is reduced, and to provide an optical filter for a display which has the functions of the hard coat film. <P>SOLUTION: In the hard coat film, the content of the ultraviolet absorber is 2-5 mass% to the solid content of the ultraviolet curing resin composition, the thickness of the transparent plastic film 12 is 100-200 μm, the thickness of the hard coat layer 14 is 6-15 μm, and the ratio of the thickness of the hard coat layer 14 to the thickness of the transparent plastic film 12 is 0.15 or below. The filter for the display includes the hard coat film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hard coat film bonded to provide glass surface protection and other functions for automobiles, railway vehicles and building windows, showcases, displays, etc., and in particular by containing an ultraviolet absorber. The present invention relates to a hard coat film having improved weather resistance (light). Further, the present invention relates to an optical filter for a display that is advantageously used in an image display section of a display such as a plasma display panel (PDP), a cathode ray tube (CRT) display, a liquid crystal display, an organic EL (electroluminescence) display, etc. provided with the hard coat film.

  Conventionally, a hard coat film is bonded to the surface of a glass such as an image display part of a display such as a window of a car, a railway vehicle and a building, a showcase, and a PDP, and has impact resistance, scratch resistance, and penetration resistance. In order to provide useful functions such as surface protection such as antireflection and electromagnetic wave shielding, it is used in various fields. The hard coat film generally includes a structure in which a hard coat layer of a curable resin such as an ultraviolet curable resin is provided on a transparent plastic film such as polyester.

  In recent years, hard coat films containing an ultraviolet absorber have been developed in order to protect substances that are easily degraded by ultraviolet rays, such as pigments, present inside the hard coat film (Patent Documents 1 to 3). In particular, when used for an optical filter for a display such as a PDP, a layer containing a pigment such as a near-infrared absorbing layer is often formed, and the demand is high. There are many types of ultraviolet absorbers such as benzophenone, cyanoacrylate, hydroxybenzoate, benzotriazole, and triazine.

  Ultraviolet absorber-containing hard coat films have been developed that contain the above-mentioned ultraviolet absorbers in a transparent plastic film (Patent Document 1) or those that contain a hard coat layer (Patent Documents 2 and 3). A combination of both is also possible.

  Here, if the transparent plastic film contains an ultraviolet absorber, the hard coat layer faces outward, so a layer made of a material that is sensitive to ultraviolet rays is formed between the transparent plastic film and the hard coat layer. There is a problem that the hard coat layer itself cannot be prevented from being deteriorated by ultraviolet rays. Furthermore, depending on the material and processing conditions of the transparent plastic film, high heat may be applied, the heat resistance of the ultraviolet absorber is required, and the type of ultraviolet absorber to be contained may be limited.

JP 2005-189553 A JP-A-11-71458 JP 2008-90067 A

  Accordingly, the present inventors have further studied a hard coat film containing an ultraviolet absorber in the hard coat layer. In this case, if the content of the ultraviolet absorber is excessive, the surface hardness of the hard coat layer cannot be maintained, so that there is a problem that the content of the ultraviolet absorber is limited. Furthermore, if the hard coat layer is excessively thick in order to secure the total amount of the UV absorber, the cure shrinkage of the UV curable resin increases, so the hard coat film curls (the film is rounded by the cure shrinkage of the resin). There is a problem that processability deteriorates.

  Accordingly, an object of the present invention is a hard coat film comprising a transparent plastic film, and a hard coat layer provided on one surface thereof, which is formed from an ultraviolet curable resin composition containing an ultraviolet absorber. An object of the present invention is to provide a hard coat film having a sufficient surface hardness and a sufficient ultraviolet ray absorbing effect and having reduced curling. Furthermore, it is providing the optical filter for a display which has a function of the said hard coat film.

  In the present invention, “sufficient surface hardness” means hardness that does not cause damage in a steel wool test (steel wool # 0000, 200 g load × 10 reciprocation), and “sufficient UV absorption effect” means 280 nm. It refers to an ultraviolet absorption effect that causes an ultraviolet transmittance of ˜360 nm to be 2% or less.

  The above object is a hard coat film comprising a transparent plastic film and a hard coat layer provided on one surface thereof and formed from an ultraviolet curable resin composition containing an ultraviolet absorber. Content rate is 2-5 mass% with respect to ultraviolet curable resin composition solid content, The film thickness of the said transparent plastic film is 100-200 micrometers, The layer thickness of the said hard-coat layer is 6-20 micrometers, The hard coat film is characterized in that the ratio of the thickness of the hard coat layer to the film thickness of the transparent plastic film is 0.15 or less.

  By optimizing the content of the UV absorber in the hard coat layer, the hard coat layer has sufficient surface hardness, and by optimizing the film thickness of the transparent plastic film and the hard coat layer, It is possible to provide a hard coat film having an excellent ultraviolet absorption effect and reduced curling.

Preferred embodiments of the hard coat film according to the present invention are as follows.
(1) The ratio of the thickness of the hard coat layer to the thickness of the transparent plastic film is 0.06 or less. Thereby, the hard coat film with which curl was further reduced can be provided.
(2) The transparent plastic film is a polyethylene terephthalate (PET) film. The PET film is highly resistant to processing loads (heat, solvent, bending, etc.), has particularly high transparency, and is excellent in processability, and is therefore optimal for a transparent plastic film as a hard coat film.
(3) The ultraviolet absorber is at least one selected from the group consisting of a triazine ultraviolet absorber, a benzophenone ultraviolet absorber, and a benzotriazole ultraviolet absorber. Thereby, it can be set as a hard coat layer with high ultraviolet absorptivity in a wide range of wavelengths, and a hard coat film having a sufficient ultraviolet absorption effect can be provided.

  Moreover, the said objective is achieved by the optical filter for a display provided with the hard coat film of this invention.

Preferred embodiments of the optical filter for display according to the present invention are as follows.
(1) A filter for a plasma display panel.
(2) A near-infrared absorption layer is provided on the display side of the hard coat layer. Since the hard coat film of the present invention is provided, it is possible to provide an optical filter for display in which deterioration of the pigment contained in the near infrared absorption layer is effectively prevented.

  According to the hard coat film of the present invention, even a hard coat film including a hard coat layer formed from an ultraviolet curable resin composition containing an ultraviolet absorber has sufficient surface hardness and sufficient ultraviolet absorption effect. Since it can be set as the hard coat film with curl being reduced, the workability of the hard coat film is not deteriorated. Therefore, the optical filter for display of the present invention can obtain the same effect as that of the hard coat film.

  Below, the hard coat film of this invention is demonstrated, referring drawings. FIG. 1 is a schematic sectional view showing a typical example of the hard coat film of the present invention.

  As illustrated, in the hard coat film 20, a hard coat layer 14 made of an ultraviolet curable resin composition is formed on the entire surface of the rectangular transparent plastic film 12. The hard coat layer 14 contains an ultraviolet absorber in an amount of 2 to 5% by mass with respect to the solid content of the ultraviolet curable resin composition. The film thickness of the transparent plastic film 12 is 100 to 200 μm, the layer thickness of the hard coat layer 14 is 6 to 20 μm, and the ratio of the layer thickness D2 of the hard coat layer 14 to the film thickness D1 of the transparent plastic film 12 (D2 / D1) is 0.15 or less.

  If the content of the ultraviolet absorber is less than 2% by mass, sufficient ultraviolet absorption effect of the hard coat film 20 cannot be obtained due to the layer thickness of the hard coat layer 14, and if it exceeds 5% by mass, the hard coat layer UV curing becomes incomplete and sufficient surface hardness cannot be obtained. If the hard coat layer 14 has a thickness of less than 6 μm, a sufficient ultraviolet absorption effect cannot be obtained due to the content of the ultraviolet absorber, and if it exceeds 20 μm, the relationship with the film thickness of the transparent plastic film 12. Therefore, curling cannot be reduced. Further, even when D2 / D1 exceeds 0.15, curling cannot be reduced. Furthermore, when the film thickness of the transparent plastic film 12 is less than 100 μm, curling cannot be reduced due to the thickness of the hard coat layer 14, and when it exceeds 200 μm, the workability of the hard coat film 20 is lowered. It becomes difficult to handle.

  The ratio of the layer thickness D2 of the hard coat layer 14 to the film thickness D1 of the transparent plastic film 12 is preferably 0.06 or less. By setting this ratio, the influence of curing shrinkage of the ultraviolet curable resin can be further suppressed, and curling of the hard coat film 20 can be further reduced.

  The material of the transparent plastic film 12 is not particularly limited as long as it is transparent (meaning “transparent to visible light”). Examples of plastics include polyester [eg, polyethylene terephthalate (PET), polybutylene terephthalate], polymethyl methacrylate (PMMA), acrylic resin, polycarbonate (PC), polystyrene, triacetate resin, polyvinyl alcohol, polyvinyl chloride, polychlorinated. Examples include vinylidene, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion-crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane and the like. Among these, polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), etc. are highly resistant to loads during processing (heat, solvent, bending, etc.) and particularly highly transparent. preferable. In particular, PET is preferable because of its excellent processability.

An easy adhesion layer for improving the adhesion of each functional layer may be provided on the surface of the transparent plastic film 12. The easy-adhesion layer is, for example, a thermosetting resin such as a copolyester resin and a polyurethane resin, or a metal oxide fine particle such as SiO ₂ , ZrO ₂ , TiO ₂ , or Al ₂ O ₃ , preferably an average. What adjusted the refractive index by mix | blending metal oxide fine particles with a particle size of 1-100 nm is used.

  Further, the ultraviolet curable resin composition of the hard coat layer 14 is generally generally an ultraviolet curable resin such as a phenol resin, a resorcinol resin, a urea resin, a melamine resin, an epoxy resin, an acrylic resin, a urethane resin, a furan resin, or a silicon resin. Is the main component. These resins are used by mixing a photopolymerization initiator or the like.

  Examples of the ultraviolet curable resin (monomer, oligomer) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-ethylhexyl polyethoxy (meth) acrylate. , Benzyl (meth) acrylate, isobornyl (meth) acrylate, phenyloxyethyl (meth) acrylate, tricyclodecane mono (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acryloylmorpholine , N-vinylcaprolactam, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, o-phenylphenyloxyethyl (meth) acrylate, neopentylglyce Di (meth) acrylate, neopentyl glycol dipropoxy di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, tricyclodecane dimethylol di (meth) acrylate, 1,6-hexanediol di (meth) Acrylate, nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tris [(meth) acryloxyethyl] isocyanurate, ditrimethylolpropane (Meth) acrylate monomers such as tetra (meth) acrylate; polyol compounds (for example, ethylene glycol, propylene glycol, neopentyl glycol, , 6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butyl-1,3-propanediol, trimethylolpropane, diethylene glycol, dipropylene glycol, polypropylene Polyols such as glycol, 1,4-dimethylolcyclohexane, bisphenol A polyethoxydiol, polytetramethylene glycol, the polyols and succinic acid, maleic acid, itaconic acid, adipic acid, hydrogenated dimer acid, phthalic acid, isophthalic acid Polyester polyols which are reaction products of polybasic acids such as acid and terephthalic acid or acid anhydrides thereof, polycaprolactone polyols which are reaction products of the polyols and ε-caprolactone, the polyols and the polyhydric acid Basic acid or this Reaction products of acid anhydrides of ε-caprolactone, polycarbonate polyols, polymer polyols, etc.) with organic polyisocyanates (eg, tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, dicyclohexane) Pentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4′-trimethylhexamethylene diisocyanate, 2,2′-4-trimethylhexamethylene diisocyanate, etc.) and a hydroxyl group-containing (meth) acrylate (for example, 2-hydroxyethyl (meth)) Acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate , Cyclohexane-1,4-dimethylol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerin di (meth) acrylate, etc.) (Meth) acrylate such as polyurethane (meth) acrylate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, etc. ) Acrylate oligomers and the like. These compounds can be used alone or in combination.

  In particular, in order to obtain more sufficient surface hardness, among the above UV curable resins (monomer, oligomer), pentaerythritol tri (meth) acrylate, pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate It is preferable to mainly use a hard polyfunctional monomer such as.

  Any compound suitable for the properties of the ultraviolet curable resin can be used as the photopolymerization initiator for the ultraviolet curable resin. For example, acetophenone such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1 Benzoin series such as benzyl dimethyl ketal, benzophenone, 4-phenylbenzophenone, benzophenone series such as hydroxybenzophenone, thioxanthone series such as isopropylthioxanthone, 2-4-diethylthioxanthone, and other special types include methylphenyl glyoxylate Etc. can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These photopolymerization initiators may be optionally selected from one or more known photopolymerization accelerators such as benzoic acid type or tertiary amine type such as 4-dimethylaminobenzoic acid. It can be used by mixing at a ratio. Moreover, it can be used by 1 type, or 2 or more types of mixture of only a photoinitiator. In particular, 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) is preferable.

  Generally the quantity of a photoinitiator is 0.1-10 mass% with respect to a resin composition, Preferably it is 0.1-5 mass%.

  Examples of the ultraviolet absorber include inorganic fine particles or organic ultraviolet absorbers. As the inorganic fine particles, one or more of titanium oxide, zinc oxide, cerium oxide, iron oxide, barium sulfate fine particles having an average particle diameter of 100 nm or less, for example, about 10 to 100 nm can be used.

  As the organic ultraviolet absorber, one or more of triazine ultraviolet absorber, benzophenone ultraviolet absorber, benzotriazole ultraviolet absorber, cyanoacrylate ultraviolet absorber, hydroxybenzoate ultraviolet absorber and the like are used. be able to.

  Examples of the triazine-based ultraviolet absorber include 2- (2-hydroxy-4-hydroxymethylphenyl) -4,6-diphenyl-s-triazine, 2- (2-hydroxy-4-hydroxymethylphenyl) -4, 6-bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (2-hydroxyethyl) phenyl] -4,6-diphenyl-s-triazine, 2- [2-hydroxy -4- (2-hydroxyethyl) phenyl] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (2-hydroxyethoxy) phenyl] -4, 6-diphenyl-s-triazine, 2- [2-hydroxy-4- (2-hydroxyethoxy) phenyl] -4,6-bis (2,4-dimethylpheny ) -S-triazine, 2- [2-hydroxy-4- (3-hydroxypropyl) phenyl] -4,6-diphenyl-s-triazine, 2- [2-hydroxy-4- (3-hydroxypropyl) phenyl ] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (3-hydroxypropoxy) phenyl] -4,6-diphenyl-s-triazine, 2- [2-hydroxy-4- (3-hydroxypropoxy) phenyl] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- [2-hydroxy-4- (4-hydroxybutyl) phenyl ] -4,6-diphenyl-s-triazine, 2- [2-hydroxy-4- (4-hydroxybutyl) phenyl] -4,6-bis (2,4-dimethylphenol) Nyl) -s-triazine, 2- [2-hydroxy-4- (4-hydroxybutoxy) phenyl] -4,6-diphenyl-s-triazine, 2- [2-hydroxy-4- (4-hydroxybutoxy) Phenyl] -4,6-bis (2,4-dimethylphenyl) -s-triazine, 2- (2-hydroxy-4-hydroxymethylphenyl) -4,6-bis (2-hydroxy-4-methylphenyl) -S-triazine, 2- [2-hydroxy-4- (2-hydroxyethyl) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [2-hydroxy- 4- (2-hydroxyethoxy) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [2-hydroxy-4- (3- Droxypropyl) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [2-hydroxy-4- (3-hydroxypropoxy) phenyl] -4,6-bis (2-hydroxy-4-methylphenyl) -s-triazine, 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) Examples include phenol, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, and the like.

  Examples of the benzophenone ultraviolet absorber include 2,2′-dihydroxy-4,4′-di (hydroxymethyl) benzophenone, 2,2′-dihydroxy-4,4′-di (2-hydroxyethyl) benzophenone, 2,2′-dihydroxy-3,3′-dimethoxy-5,5′-di (hydroxymethyl) benzophenone, 2,2′-dihydroxy-3,3′-dimethoxy-5,5′-di (2-hydroxy) Ethyl) benzophenone, 2,2′-dihydroxy-3,3′-di (hydroxymethyl) -5,5′-dimethoxybenzophenone, 2,2′-dihydroxy-3,3′-di (2-hydroxyethyl)- 5,5′-dimethoxybenzophenone, 2,2-dihydroxy-4,4-dimethoxybenzophenone and the like can be mentioned.

  Examples of the benzotriazole ultraviolet absorber include 2- [2′-hydroxy-5 ′-(hydroxymethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(2-hydroxyethyl). ) Phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5 '-(3-hydroxypropyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-methyl-5'- (Hydroxymethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-methyl-5 ′-(2-hydroxyethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy- 3′-methyl-5 ′-(3-hydroxypropyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-tert-butyl-5 ′-( Hydroxymethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-t-butyl-5 ′-(2-hydroxyethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy -3′-t-butyl-5 ′-(2-hydroxyethyl) phenyl] -5-chloro-2H-benzotriazole, 2- [2′-hydroxy-3′-t-butyl-5 ′-(3- Hydroxypropyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-t-octyl-5 ′-(hydroxymethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3 '-T-octyl-5'-(2-hydroxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-t-octyl-5 '-(3-hydroxypro ) Phenyl] -2H-benzotriazole or the like, or 2,2′-methylenebis [6- (2H-benzotriazoly-2-yl) -4- (hydroxymethyl) phenol], 2,2 ′;-methylenebis [6- (2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol], 2,2'-methylenebis [6- (5-chloro-2H-benzotriazoly-2-yl) -4- (2-hydroxy Ethyl) phenol], 2,2'-methylenebis [6- (5-bromo-2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol], 2,2'-methylenebis [6- (2H -Benzotriazoly-2-yl) -4- (3-hydroxypropyl) phenol], 2,2'-methylenebis [6- (5-chloro-2H-benzotri) Zol-2-yl) -4- (3-hydroxypropyl) phenol], 2,2′-methylenebis [6- (5-bromo-2H-benzotriazoly-2-yl) -4- (3-hydroxypropyl) phenol ], 2,2'-methylenebis [6- (2H-benzotriazoly-2-yl) -4- (4-hydroxybutyl) phenol], 2,2'-methylenebis [6- (5-chloro-2H-benzotriazoly- 2-yl) -4- (4-hydroxybutyl) phenol], 2,2′-methylenebis [6- (5-bromo-2H-benzotriazoly-2-yl) -4- (4-hydroxybutyl) phenol], 3,3- {2,2′-bis [6- (2H-benzotriazoly-2-yl) -1-hydroxy-4- (2-hydroxyethyl) phenyl]} propane, 2,2 -{2,2'-bis [6- (2H-benzotriazoly-2-yl) -1-hydroxy-4- (2-hydroxyethyl) phenyl]} butane, 2,2'-oxybis [6- (2H- Benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol], 2,2′-bis [6- (2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol] sulfide, 2 2,2'-bis [6- (2H-benzotriazoly-2-yl) -4- (2-hydroxyethyl) phenol] sulfoxide, 2,2'-bis [6- (2H-benzotriazoly-2-yl) -4 -(2-hydroxyethyl) phenol] sulfone, 2,2′-bis [6- (2H-benzotriazoli-2-yl) -4- (2-hydroxyethyl) phenol] amine, and the like. It is.

  Examples of the cyanoacrylate ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3′-diphenyl acrylate, ethyl-2-cyano-3,3′-diphenyl acrylate, and the like.

  Hydroxybenzoate UV absorbers include phenyl salicylate, 4-t-butylphenyl salicylate, 2,5-t-butyl-4-hydroxybenzoic acid n-hexadecyl ester, 2,4-di-t -Butylphenyl-3 ', 5-di-t-butyl-4'-hydroxybenzoate and the like.

  As the ultraviolet absorber, one or two of triazine-based, benzophenone-based, and benzotriazole-based ultraviolet absorbers are used because they have a high ultraviolet-absorbing property in a wide wavelength range (from about 280 to 360 nm) from a short wavelength region to a long wavelength region. It is preferable to use more than one species.

  Examples of the film constituent layer other than the hard coat layer of the hard coat film include an antireflection layer (low refractive index layer, high refractive index layer), conductive layer, near infrared absorption layer, toning layer, etc. There is no restriction | limiting, It can comprise freely by a use.

  FIG. 2 is a schematic sectional view showing another representative example of the hard coat film of the present invention. As shown in the figure, in the hard coat film 30, a hard coat layer 24 of an ultraviolet curable resin composition is formed over the entire surface of the rectangular transparent plastic film 22, and a high refractive index layer 25 and an antireflection layer are formed thereon. A low refractive index layer 26 is formed. Further, a near-infrared absorbing layer 27 and an adhesive layer 28 are formed on the other surface of the transparent plastic film 22 on which the hard coat layer 24 is formed, and the hard coat film 30 is interposed via the adhesive layer 28. The glass 31 is attached.

  The transparent plastic film 22 and the hard coat layer 24 are the same as the transparent plastic film 12 and the hard coat layer 14 in the case of FIG. The antireflection layer may be a layer combined with the high refractive index layer 25 and the low refractive index layer 26, or may be either the high refractive index layer 25 or the low refractive index layer 26.

  The near-infrared absorbing layer 27 is formed according to the application. Since the hard coat film of the present invention has a sufficient ultraviolet absorption effect, it is suitable as a hard coat film for forming a near-infrared absorption layer containing a dye that is easily deteriorated by ultraviolet rays. Although the pressure-sensitive adhesive layer 28 may be omitted, it is generally preferable that the hard coat film is provided because it is used while being adhered to glass.

The high refractive index layer 25 of the antireflection layer is made of ZnO doped with ITO, ATO, Sb ₂ O ₃ , SbO ₂ , In ₂ O ₃ , SnO ₂ , ZnO, and Al in a polymer (preferably UV curable resin). It is preferable to use a layer (cured layer) in which conductive metal oxide fine particles (inorganic compound) such as TiO ₂ are dispersed. The metal oxide fine particles preferably have an average particle size of 10 to 10,000 nm, preferably 10 to 50 nm. In particular, ITO (especially having an average particle diameter of 10 to 50 nm) is preferable. The film thickness is generally in the range of 10 to 500 nm, preferably 20 to 200 nm.

  The low refractive index layer 26 of the antireflection layer is composed of fine particles such as silica and fluororesin, preferably 10 to 40% by weight (preferably 10 to 30% by weight) of hollow silica in a polymer (preferably UV curable resin). A dispersed layer (cured layer) is preferred. The film thickness is generally in the range of 10 to 500 nm, preferably 20 to 200 nm. As the hollow silica, those having an average particle diameter of 10 to 100 nm, preferably 10 to 50 nm, and a specific gravity of 0.5 to 1.0, preferably 0.8 to 0.9 are preferable.

  The near-infrared absorbing layer 27 is generally obtained by forming a layer containing a pigment or the like on the surface of the substrate film. The near-infrared absorbing layer can be obtained, for example, by applying a coating liquid containing the above-described pigment and binder resin, and if necessary, drying and curing. Alternatively, it can also be obtained by applying a coating solution containing the above-mentioned pigment and binder resin and simply drying it. When used as a film, it is generally a near-infrared cut film, such as a film containing a pigment or the like. The dye generally has an absorption maximum at a wavelength of 800 to 1200 nm. Examples include phthalocyanine dyes, metal complex dyes, nickel dithiolene complex dyes, cyanine dyes, squarylium dyes, polymethine dyes, Examples thereof include azomethine dyes, azo dyes, polyazo dyes, diimonium dyes, aminium dyes, and anthraquinone dyes, and cyanine dyes, phthalocyanine dyes, and diimonium dyes are particularly preferable. These dyes can be used alone or in combination. Examples of the binder resin include thermoplastic resins such as acrylic resins. The layer thickness of the near infrared absorbing layer is generally 0.5 to 50 μm.

  The adhesive layer 28 is generally transparent, and any resin can be used as long as it has an adhesive function for adhering to a glass substrate. For example, an acrylic adhesive formed from an ethylene-vinyl acetate copolymer (EVA), an ethylene-methyl acrylate copolymer, butyl acrylate, a rubber adhesive, SEBS (styrene / ethylene / butylene / styrene) and TPE-based pressure-sensitive adhesives and adhesives mainly composed of a thermoplastic elastomer (TPE) such as SBS (styrene / butadiene / styrene) can also be used.

  The layer thickness is generally in the range of 5 to 500 μm, particularly 10 to 100 μm. In general, the optical filter can be equipped by pressing the pressure-sensitive adhesive layer on a glass plate of a display.

  When EVA is used as the material for the pressure-sensitive adhesive layer, the EVA has a vinyl acetate content of 5 to 50% by weight, preferably 15 to 40% by weight. When the vinyl acetate content is less than 5% by weight, there is a problem in transparency, and when it exceeds 40% by weight, the mechanical properties are remarkably deteriorated and the film formation becomes difficult and the films are easily blocked.

  As the cross-linking agent, an organic peroxide is suitable for heat cross-linking and is selected in consideration of sheet processing temperature, cross-linking temperature, storage stability, and the like. Examples of peroxides that can be used include 2,5-dimethylhexane-2,5-dihydroperoxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3; -Butyl peroxide; t-butylcumyl peroxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; dicumyl peroxide; α, α'-bis (t-butylperoxyisopropyl) ) Benzene; n-butyl-4,4-bis (t-butylperoxy) valerate; 2,2-bis (t-butylperoxy) butane; 1,1-bis (t-butylperoxy) cyclohexane; , 1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane; t-butylperoxybenzoate; benzoyl peroxide; Luperoxyacetate; 2,5-dimethyl-2,5-bis (tertiarybutylperoxy) hexyne-3; 1,1-bis (tertiarybutylperoxy) -3,3,5-trimethylcyclohexane; 1-bis (tert-butylperoxy) cyclohexane; methyl ethyl ketone peroxide; 2,5-dimethylhexyl-2,5-bisperoxybenzoate; tert-butyl hydroperoxide; p-menthane hydroperoxide; p-chlorobenzoyl Peroxides; tertiary butyl peroxyisobutyrate; hydroxyheptyl peroxide; chlorohexanone peroxide. These peroxides are used singly or in combination of two or more, and are usually used at a ratio of 5 parts by mass or less, preferably 0.5 to 5.0 parts by mass with respect to 100 parts by mass of EVA. .

  The organic peroxide is usually kneaded with EVA using an extruder, a roll mill or the like, but may be dissolved in an organic solvent, a plasticizer, a vinyl monomer or the like and added to the EVA film by an impregnation method.

  Various acryloxy group or methacryloxy group and allyl group-containing compounds can be added to improve EVA physical properties (mechanical strength, optical properties, adhesiveness, weather resistance, whitening resistance, crosslinking speed, etc.). . As the compound used for this purpose, acrylic acid or methacrylic acid derivatives, for example, esters and amides thereof are the most common. As the ester residue, in addition to alkyl groups such as methyl, ethyl, dodecyl, stearyl, lauryl, cyclohexyl groups , Tetrahydrofurfuryl group, aminoethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, 3-chloro-2-hydroxypropyl group and the like. Further, esters with polyfunctional alcohols such as ethylene glycol, triethylene glycol, polyethylene glycol, trimethylolpropane, and pentaerythritol can also be used. A typical amide is diacetone acrylamide.

  Examples thereof include polyfunctional esters such as acrylic or methacrylic acid esters such as trimethylolpropane, pentaerythritol, glycerin, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl maleate, etc. Examples include allyl group-containing compounds. These are used alone or in combination of two or more, and are usually used in an amount of 0.1 to 2 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of EVA. .

  When EVA is crosslinked by light, a photosensitizer is usually used in an amount of 5 parts by mass or less, preferably 0.1 to 3.0 parts by mass based on 100 parts by mass of EVA instead of the peroxide.

  In this case, usable photosensitizers include, for example, benzoin, benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, dibenzyl, 5-nitroacenaphthene, hexachlorocyclopentadiene, p-nitrodiphenyl. , P-nitroaniline, 2,4,6-trinitroaniline, 1,2-benzanthraquinone, 3-methyl-1,3-diaza-1,9-benzanthrone, and the like. Alternatively, two or more types can be mixed and used.

  Moreover, a silane coupling agent is used in combination as an adhesion promoter. As this silane coupling agent, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycid Xylpropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- β (aminoethyl) -γ-aminopropyltrimethoxysilane and the like can be mentioned.

  The silane coupling agent is generally used in an amount of 0.001 to 10 parts by mass, preferably 0.001 to 5 parts by mass, based on 100 parts by mass of EVA, and one or more types are mixed and used.

  In addition, the EVA transparent adhesive layer may contain a small amount of an ultraviolet absorber, an infrared absorber, an anti-aging agent, a coating processing aid, a colorant, etc., and in some cases, carbon black, hydrophobic silica. A small amount of a filler such as calcium carbonate may be included.

  For example, after the EVA and the above-mentioned additive are mixed and kneaded with an extruder, a roll or the like, the pressure-sensitive adhesive layer is formed into a predetermined shape by a film forming method such as a calendar, roll, T-die extrusion or inflation. It is manufactured by.

  As the material of the release sheet provided on the pressure-sensitive adhesive layer, a transparent polymer having a glass transition temperature of 50 ° C. or higher is preferable. Examples of such a material include polyesters such as polyethylene terephthalate, polycyclohexylene terephthalate, and polyethylene naphthalate. In addition to resins, nylon 46, modified nylon 6T, nylon MXD6, polyamide resins such as polyphthalamide, ketone resins such as polyphenylene sulfide and polythioether sulfone, and sulfone resins such as polysulfone and polyether sulfone. Mainly composed of polymers such as ether nitrile, polyarylate, polyetherimide, polyamideimide, polycarbonate, polymethyl methacrylate, triacetyl cellulose, polystyrene, polyvinyl chloride It can be used fat. Of these, polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate can be suitably used. The thickness is preferably 10 to 200 μm, particularly preferably 30 to 100 μm.

  The hard coat filter of the present invention can be produced by a known method. For example, a hard coat layer is formed on the entire surface of the transparent plastic film, and an antireflection layer is formed as necessary. After the antireflection layer forming step, if necessary, a near-infrared absorbing layer and an adhesive layer are formed on the other surface of the surface on which the hard coat layer of the transparent plastic film is formed.

  Although it may be processed into a single wafer as described above, it can also be formed continuously as follows. That is, a hard coat layer or the like is formed on a long transparent plastic film, and a near-infrared absorbing layer or the like is continuously formed on the other surface, and then cut to a required length.

  In order to form each layer, for example, a transparent plastic film is coated with a coating solution in which an ultraviolet curable resin composition is dissolved in a solvent such as toluene, and then dried, and then cured by irradiation with ultraviolet rays. That's fine. This wet coating method has the advantages of being able to form a film uniformly at a high speed at a low cost, improving the adhesion, and increasing the hardness of the film. In this case, each layer may be applied and cured one by one, or all the layers may be applied and then cured together. In the case of continuous processing, the coating surface may be damaged unless it is cured after coating of each layer. Therefore, it is preferable to coat and cure each layer one by one.

  Many UV light sources that emit light in the ultraviolet to visible range can be used, such as ultra-high pressure, high pressure, low pressure mercury lamps, chemical lamps, xenon lamps, halogen lamps, mercury lamps, carbon arc lamps, incandescent lamps, and laser light. Etc. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but is about several seconds to several minutes. Moreover, in order to accelerate curing, the laminate may be preheated to 40 to 120 ° C. and irradiated with ultraviolet rays.

  FIG. 3 is a schematic sectional view showing a typical example of the optical filter for display according to the present invention. As shown in the figure, in the display optical filter 40, a mesh-like conductive layer 33 is formed on the entire surface of a rectangular transparent transparent plastic film 32. An intermediate layer may be formed between the transparent plastic film 32 and the conductive layer 33 (not shown). A hard coat layer 34 is formed thereon, and a high refractive index layer 35 and a low refractive index layer 36 are formed thereon as an antireflection layer. A near-infrared layer 37 and an adhesive layer 38 are formed on the other surface of the transparent plastic film 32 on which the conductive layer 33 is formed, and the optical filter 40 is interposed between the glass substrate 41 and the adhesive layer 38. It is attached to. In order to conduct electricity from the conductive layer 33 to the outside, the optical filter 40 has a functional layer such as a hard coat layer around the optical filter removed by laser irradiation or the like to expose the conductive layer, or conductive adhesive. A structure is included in which the tape is sandwiched between conductive layers and grounded to the outside (not shown).

  The optical filter for a display having such a structure is particularly suitable for an optical filter for a plasma display panel in which high-frequency pulse discharge is performed on a light emitting portion for image display and there is unnecessary electromagnetic radiation.

  The transparent plastic film 32 and the hard coat layer 34 are the same as the transparent plastic film 12 and the hard coat layer 14 in the case of FIG. Therefore, the optical filter for display is provided with the hard coat film of the present invention, has a sufficient surface hardness and a sufficient ultraviolet absorption effect, and curl of the optical filter for display is reduced.

  Further, the high refractive index layer 35 and the low refractive index layer 36 of the antireflection layer are the same as the high refractive index layer 25 and the low refractive index layer 26 in the case of FIG.

  Further, the near-infrared absorbing layer 37 and the adhesive layer 38 are the same as the near-infrared layer 27 and the adhesive layer 28 in the case of FIG. However, the near-infrared absorbing layer 37 may have a color tone adjusting function by providing an absorbing function of neon emission (neon cut function). For this purpose, a neon-emission absorption layer (neon cut layer) may be provided, but a neon-emission selective absorption dye may be included in the near-infrared absorption layer.

  Neon luminescent selective absorption dyes include cyanine dyes, squarylium dyes, anthraquinone dyes, phthalocyanine dyes, polymethine dyes, polyazo dyes, azurenium dyes, diphenylmethane dyes, and triphenylmethane dyes. it can. Such a selective absorption dye is required to have a selective absorption of neon emission near 585 nm and a small absorption at other visible light wavelengths, so that the absorption maximum wavelength is 575 to 595 nm and the absorption spectrum half width is What is 40 nm or less is preferable.

  Also, when combining multiple types of near-infrared or neon luminescent absorbing dyes, if there is a problem with the solubility of the dye, if there is a reaction between the dyes due to mixing, if there is a decline in heat resistance, moisture resistance, etc. All the near-infrared absorbing dyes need not be contained in the same layer, and may be contained in another layer. Further, a coloring pigment, an ultraviolet absorber, an antioxidant, and the like may be added as long as the optical properties are not greatly affected.

  As near-infrared absorption characteristics, the transmittance of 850 to 1000 nm is preferably 20% or less, more preferably 15% or less. Moreover, as selective absorptivity, it is preferable that the transmittance | permeability of 585 nm is 50% or less. Especially in the former case, there is an effect of reducing the transmittance in a wavelength region where malfunction of a remote controller of a peripheral device is pointed out. In the latter case, an orange color having a peak at 575 to 595 nm is color reproducibility. This has the effect of absorbing the orange wavelength, thereby improving the redness and improving the color reproducibility.

  The near-infrared absorption layer 37 and the like may be omitted, but the display optical filter of the present invention has a sufficient ultraviolet absorption effect, and therefore a display optical filter having a near-infrared absorption layer containing a dye that is easily deteriorated by ultraviolet rays. Suitable as

  The conductive layer 33 is generally set to be 10Ω / □ or less, preferably in the range of 0.001 to 5Ω / □, particularly 0.005 to 5Ω / □. The conductive layer 33 may be a mesh-like conductive layer as shown in FIG. 3 or a layer obtained by a vapor deposition method (a transparent conductive thin film of metal oxide (ITO or the like)). Further, it may be an alternate laminate of a metal oxide dielectric film such as ITO and a metal layer such as Ag (eg, ITO / silver / ITO / silver / ITO laminate).

  As the mesh-like conductive layer, metal fibers and metal-coated organic fiber metals made into a mesh, copper foil on a transparent film etched into a mesh and provided with openings, conductive on the transparent film And the like, in which a conductive ink is printed in a mesh shape.

  In the case of a mesh-shaped conductive layer, the mesh preferably has a wire diameter of 1 μm to 1 mm and an aperture ratio of 40 to 95% made of metal fibers and / or metal-coated organic fibers. A more preferable wire diameter is 10 to 500 μm, and an aperture ratio is 50 to 95%. When the wire diameter exceeds 1 mm in the mesh-like conductive layer, the electromagnetic wave shielding property is improved, but the aperture ratio is lowered and cannot be made compatible. If it is less than 1 μm, the strength as a mesh is lowered and handling becomes difficult. Further, when the aperture ratio exceeds 95%, it is difficult to maintain the shape as a mesh. When the aperture ratio is less than 40%, the light transmittance is reduced, and the amount of light from the display is also reduced.

  In addition, the aperture ratio of a mesh means the area ratio which the opening part occupies in the projection area of the said mesh.

  As the metal of the mesh-like conductive layer and the metal of the metal-coated organic fiber, copper, stainless steel, aluminum, nickel, titanium, tungsten, tin, lead, iron, silver, carbon or alloys thereof, preferably copper, Stainless steel and nickel are used.

  As the organic material for the metal-coated organic fiber, polyester, nylon, vinylidene chloride, aramid, vinylon, cellulose and the like are used.

  When a conductive foil such as a metal foil is subjected to pattern etching, copper, stainless steel, aluminum, nickel, iron, brass, or an alloy thereof, preferably copper, stainless steel, or aluminum is used as the metal of the metal foil.

  If the thickness of the metal foil is too thin, it is not preferable in terms of handleability and workability of pattern etching, and if it is too thick, it affects the thickness of the film obtained, and the time required for the etching process becomes long. The thickness is preferably about 1 to 200 μm.

  The shape of the etching pattern is not particularly limited, and examples thereof include a grid-like metal foil in which square holes are formed, and a punching metal-like metal foil in which circular, hexagonal, triangular or elliptical holes are formed. It is done. Further, the holes are not limited to those regularly arranged, and may be a random pattern. It is preferable that the area ratio of the opening part in the projection surface of this metal foil is 20 to 95%.

  In addition to the above, as a mesh-like conductive layer, dots are formed on the film surface by a material soluble in a solvent, and a conductive material layer made of a conductive material insoluble in a solvent is formed on the film surface, A mesh-like conductive layer obtained by bringing the film surface into contact with a solvent to remove the dots and the conductive material layer on the dots may be used.

  A metal plating layer may be further provided on the conductive layer in order to improve the conductivity (particularly in the case of forming dots with a material soluble in the solvent). The metal plating layer can be formed by a known electrolytic plating method or electroless plating method. As the metal used for plating, generally, copper, copper alloy, nickel, aluminum, silver, gold, zinc, tin or the like can be used, preferably copper, copper alloy, silver, or nickel, In particular, it is preferable to use copper or a copper alloy from the viewpoint of economy and conductivity.

  Moreover, you may give anti-glare performance. When this anti-glare treatment is performed, a blackening treatment may be performed on the surface of the (mesh) conductive layer. For example, oxidation treatment of a metal film, black plating such as chromium alloy, application of black or dark ink, and the like can be performed.

  When an intermediate layer is formed between the transparent plastic film and the conductive layer, a polyester resin is mainly used as the material. The polyester resin is generally obtained by polycondensation of glycol and a polyvalent (generally divalent) carboxylic acid. Examples of glycols include ethylene glycol, diethylene glycol, propylene glycol, butanediol, hexanediol, 1,4-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-methyl- 2-ethyl-1,3-propanediol, 2-methyl-2-butyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1 , 3-propanediol, 2-methyl-2-n-hexyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3- Propanediol, 2-ethyl-2-n-hexyl-1,3-propanediol, 2,2-di-n-buty 1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, it may be mentioned 2,2-di -n- hexyl-1,3-propanediol. Ethylene glycol, diethylene glycol, propylene glycol, butanediol, hexanediol, 1,4-cyclohexanedimethanol, and 2,2-dimethyl-1,3-propanediol are preferred.

  Examples of polyvalent (generally divalent) carboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenylcarboxylic acid, 2,6-naphthalenedicarboxylic acid; adipic acid, succinic acid, malonic acid, glutaric acid And pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid and maleic acid. Terephthalic acid, isophthalic acid, adipic acid, succinic acid, azelaic acid and sebacic acid are preferred.

  The weight average molecular weight of the polyester resin is generally in the range of 1000 to 50000, particularly preferably in the range of 2000 to 20000. The number average molecular weight is generally in the range of 1000 to 50000, and particularly preferably in the range of 2000 to 20000.

  As a resin component other than the polyester resin, an acrylic resin, a styrene-maleic acid graft polyester resin, an acrylic graft polyester resin, an epoxy resin, a urethane resin, a silicon resin, or the like may be used.

  The coating liquid for forming the intermediate layer can be obtained by mixing and dissolving the polyester resin and various additives in an organic solvent. And an intermediate | middle layer can be obtained by coating and drying the obtained coating liquid by a well-known coating method. Since this coating liquid usually does not contain a curing agent, the intermediate layer can be formed by evaporating the solvent after coating.

  The optical filter for display of the present invention is produced in the same manner as the hard coat film described above except that a conductive layer and an intermediate layer are formed as necessary before forming the hard coat layer on the transparent plastic film. can do.

Hereinafter, the present invention will be described with reference to examples.
Example 1 Content of UV Absorber in Hard Coat Layer In order to optimize the content of the UV absorber contained in the UV curable resin composition of the hard coat layer, the hard coat layer was changed by changing the content of the UV absorber. A film was prepared and the surface hardness was evaluated by a steel wool test.
(1) Production of hard coat film (i) UV curable resin composition: (dipentaerythritol triacrylate as resin component; 50 parts by mass, and ethoxylated bisphenol A diacrylate (ethylene oxide (EO); 4 mol addition)); 50 parts by mass was used, and Irgacure 184 (manufactured by Ciba Specialty Chemicals); 5 parts by weight was added as a polymerization initiator.
(Ii) UV absorber: As a triazine UV absorber, TINUVIN 460 (manufactured by Ciba Specialty Chemicals, hydroxyphenyltriazine) is 3.8%, 7.4%, and 11% in the solid content of the above composition. It added so that it might become.
(Iii) Preparation of coating solution: (Smoothed with a mixture of 2-propanol and cyclohexanone in a mass ratio of 5: 5, and a mixture of the above composition and solvent in a ratio of 4: 6. 0.02% by mass of KF96-200CS (manufactured by Shin-Etsu Silicone) was added as an agent, and the mixture was stirred at room temperature for 1 hour to prepare a hard coat layer coating solution.
(Iv) Formation of a hard coat layer: (on the surface of a 100 μm long polyethylene terephthalate (PET) film having an easy-adhesion layer (polyester polyurethane; thickness 20 nm)) Was applied with a desktop bar coater so that the hard coat layer had a thickness of 6 μm, dried at 120 ° C. for 30 seconds, and then cured by irradiating with an ultraviolet ray having an integrated light amount of 600 mJ / cm ² .
(2) Evaluation of surface hardness (steel wool test)
(I) Method: Using steel wool # 0000, the test surface was reciprocated by 200 g load × 10. According to this test, a case where no scratch was observed on the surface by visual observation was accepted, and a case where a scratch was found was rejected.
(Ii) Results Table 1 shows the results of the steel wool test. When the ultraviolet absorber content was 3.8% by mass, a sufficient surface hardness was observed in the hard coat film, but when the content was 7.4% by mass or more, sufficient surface hardness was not obtained.

(Example 2) Thickness of transparent plastic film and hard coat layer In order to optimize the film thickness of the transparent plastic film and the hard coat layer, the transparent plastic film of various thicknesses and the hard coat of various layer thicknesses A hard coat film of a layer was prepared, and the curl state of the hard coat film was evaluated.

(1) Preparation of hard coat layer Except that the film thickness of the transparent plastic film is 50 to 200 μm, the thickness of the hard coat layer is 6 to 20 μm, and the ultraviolet absorber content is 3.8% by mass. Produced a hard coat film in the same manner as in Example 1. In addition, as a result of setting the ultraviolet absorber content to 3.8% by mass, in order to achieve a sufficient ultraviolet absorption effect (an ultraviolet absorption effect in which the ultraviolet transmittance at 280 nm to 360 nm is 2% or less), The layer thickness was required to be 6 μm or more. In addition, when the film thickness of the transparent plastic film exceeds 200 μm, when the hard coat film of the present invention is produced, the workability becomes low and it becomes difficult to handle, so 200 μm was made the upper limit.
(2) Evaluation of curl reduction effect (i) Method: A hard coat film cut to a 10 cm square is placed on a horizontal work bench, and the hard coat floats from the horizontal plane of the work bench due to “warping” due to the curl of the hard coat film. The height of the end of the film was measured. According to this test, when the height was 0 mm or more and less than 5 mm, ◎ was given when the height was 5 mm or more but less than 20 mm, Δ was given when it was 20 mm or more but less than 40 mm, x was given when it was 40 mm or more, and ○ or more was judged acceptable.
(Ii) Results Table 2 shows the evaluation results of the curl reduction effect. When the film thickness of the transparent plastic film was less than 100 μm, curling could not be sufficiently reduced even when the hard coat layer thickness was 6 μm. Moreover, when the layer thickness of the hard coat layer exceeded 20 μm, curling could not be sufficiently reduced even if the film thickness of the transparent plastic film was 200 μm (not shown). Further, even when the transparent plastic film is 100 μm or more, the curl cannot be sufficiently reduced when the ratio (D2 / D1) of the hard coat layer thickness D2 to the transparent plastic film thickness D1 exceeds 0.15. It was. Therefore, the curl reduction effect was acceptable when the film thickness of the transparent plastic film was 100 to 200 μm, the thickness of the hard coat layer was 6 to 20 μm, and D2 / D1 was 0.15 or less. Moreover, when D2 / D1 was 0.06 or less among the combinations that passed, the evaluation was ◎, and it was recognized that curling was further reduced.

(Example 3) Evaluation of ultraviolet absorption effect of hard coat film (1) Durability of hard coat layer itself (i) Production of hard coat film Except that the content of the ultraviolet absorber was 3.8% by mass (implementation) A hard coat film was prepared in the same manner as in Example 1). As a comparative example, a hard coat film was prepared in the same manner as in (Example 1) without containing an ultraviolet absorber.

(Ii) Evaluation of UV resistance (xenon test)
(A) Method: The amount of change in transmittance of 450 nm of the hard coat film was measured after irradiation with xenon arc for 500 hours by a xenon weather meter (XL75, manufactured by Suga Test Instruments Co., Ltd.).

    (B) Results: The results of the xenon test are shown in Table 3. The hard coat layer of the hard coat film of the present invention was prevented from being deteriorated by a xenon lamp, and exhibited high weather resistance (light).

(2) Durability of near-infrared absorbing layer (i) Production of hard coat film (1) For the hard coat films of Examples and Comparative Examples shown in (i), a hard coat layer of a transparent plastic film was formed respectively. A near infrared absorbing layer was formed on the other surface of the surface. As a control, a conventional product in which a near-infrared absorbing layer was formed on a UV absorber-containing PET was prepared.

(Ii) Evaluation of UV resistance (xenon test)
(A) Method: (1) Xenon arc was irradiated in the same manner as in (i), and the amount of change in transmittance at 850 nm, 950 nm, and 1050 nm of the hard coat film (with a near infrared absorption layer) was measured. For reference, a conventional UV absorber-containing PET was also tested.
(B) Results: The results of the xenon test are shown in Table 4. The near-infrared absorbing layer of the hard coat film of the present invention was prevented from being deteriorated by a xenon lamp, and exhibited high weather resistance (light) similar to that of a conventional UV absorber-containing PET.

  In addition, this invention is not limited to the structure and Example of said embodiment, A various deformation | transformation is possible within the range of the summary of invention.

It is a schematic sectional drawing which shows one typical example of the hard coat film of this invention. It is a schematic sectional drawing which shows another representative example of the hard coat film of this invention. It is a schematic sectional drawing which shows one typical example of the optical filter for displays of this invention.

Explanation of symbols

12, 22, 32 Transparent plastic film 14, 24, 34 Hard coat layer 25, 35 High refractive index layer 26, 36 Low refractive index layer 27, 37 Near infrared absorbing layer 28, 38 Adhesive layer 20, 30 Hard coat film 31 Glass 33 Conductive layer 40 Display optical filter 41 Glass substrate

Claims (7)

A hard coat film comprising a transparent plastic film, and a hard coat layer provided on one surface thereof and formed from an ultraviolet curable resin composition containing an ultraviolet absorber,
The content of the ultraviolet absorber is 2 to 5% by mass with respect to the solid content of the ultraviolet curable resin composition,
The film thickness of the transparent plastic film is 100 to 200 μm,
The hard coat layer has a layer thickness of 6 to 20 μm,
A ratio of the thickness of the hard coat layer to the film thickness of the transparent plastic film is 0.15 or less.   The hard coat film according to claim 1, wherein a ratio of a layer thickness of the hard coat layer to a film thickness of the transparent plastic film is 0.06 or less.   The hard coat film according to claim 1, wherein the transparent plastic film is a polyethylene terephthalate film.   The said ultraviolet absorber is at least 1 sort (s) selected from the group which consists of a triazine type ultraviolet absorber, a benzophenone type ultraviolet absorber, and a benzotriazole type ultraviolet absorber, The any one of Claims 1-3 characterized by the above-mentioned. The hard coat film as described in the item.   The optical filter for a display provided with the hard coat film of any one of Claims 1-4.   6. The display optical filter according to claim 5, which is an optical filter for a plasma display panel.   The display optical filter according to claim 5, further comprising a near-infrared absorbing layer on the display side of the hard coat layer.

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