JP2008238646A - Hard coat film and anti-reflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat film and an anti-reflection film or a thermoplastic film having a hard coat layer overlying it, the film having excellent surface hardness, preventing generation of an interference pattern, preventing coloration and uneven coloration of reflected light after anti-reflection work, and giving an anti-reflection effect and a near infrared ray-absorbing effect when used for a filter of a plasma display television set. <P>SOLUTION: The hard coat film has the hard coat layer with an uneven structure overlying at least one surface of a polyester film wherein the surface of the hard coat has a three-dimensional surface roughness parameter as shown in arithmetical mean roughness Sa of not less than 15 nm and less than 150 nm and a kurtosis Sku of a surface height distribution of not less than 1 to not more than 3; the hard coat film shows light transmittance of not more than 30% in a wave length of 820 to 1,000 nm; and the polyester film surface has an uneven structure on the boundary surface between the hard coat layer and the polyester film, and the hard coat surface in the cross sectional direction of a protrusion of the uneven structure is concave. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hard coat film, and more specifically, a base film suitable for an antireflection film or a touch panel film, having excellent scratch resistance, less interference fringes, and reflection when antireflection processing is applied to the surface layer. The present invention relates to an antireflection film that has characteristics of very little light coloring and uneven coloring, and that can provide an anti-reflection effect and a near-infrared absorption effect when used as a filter for a plasma display television.

  Biaxially oriented polyester film has excellent properties such as mechanical properties, dimensional stability, heat resistance, transparency, and electrical insulation properties. Therefore, magnetic recording materials, packaging materials, electrical insulation materials, various photographic applications, graphic arts, etc. It is used in many applications such as optical display materials. However, the surface hardness is not sufficient, and there is a drawback that the surface is easily damaged by contact with other hard materials, friction, scratching, and the like. In order to solve this, conventionally, a method of laminating various hard coat layers has been applied.

  Since a biaxially oriented polyester film has a high degree of crystal orientation, if a hard coat layer is directly provided, the adhesiveness becomes insufficient. Therefore, a method using an adhesive layer on the polyester film is generally performed.

  When a hard coat layer is provided on such a method or directly on a biaxially oriented polyester film, an in-plane refractive index difference occurs between the hard coat layer and the biaxially oriented polyester film surface or the adhesive layer surface that is in contact with the hard coat layer. Therefore, when it is used as a base material for an optical application, for example, an antireflection film or a touch panel film, an interference pattern corresponding to the uneven thickness of the hard coat layer is generated.

  The occurrence of the interference pattern significantly impairs the visibility of the display when used in the above-described applications. In order to improve this phenomenon, studies have been made to improve the accuracy of the coating thickness or to increase the refractive index of the hard coat layer to reduce the difference in refractive index from the base film (Patent Document 1). Also, a method of embossing the surface of the base film by a hot press method to provide irregularities on the surface and providing a hard coat layer on the surface (Patent Document 2), a hard coat using a solvent that dissolves the base film A method of dissolving or swelling a base material at the time of application using a layer forming paint (Patent Document 3) has been proposed. However, there is a limit to match the refractive index of the hard coat layer or adhesive layer to the in-plane refractive index of about 1.60 to 1.65, which is a normal biaxially oriented polyester film. The interference pattern is not completely erased.

  In addition, the interference fringes are slightly invisible by the method of forming irregularities on the surface of the base film by a method such as hot pressing and providing a hard coat layer, but there is a problem that the reflection suppression effect cannot be sufficiently satisfied. . Furthermore, the method of dissolving or swelling the base film is a biaxially oriented polyester film that has excellent solvent resistance, so there is almost no compatible solvent, and the only ortho-chlorophenol that can be used can adversely affect the working environment. There is a problem that it cannot be easily removed.

  Furthermore, since the normal hard coat layer is very smooth, when antireflection processing is performed on the hard coat layer, the wavelength dependence of the reflected light intensity on the antireflection layer surface increases, and a specific color looks strong, There is a problem that color unevenness occurs due to uneven application of the antireflection layer.

  In addition, the front filter of the plasma display is accompanied by strong light emission in the vicinity of wavelengths of 823 nm, 882 nm, 916 nm, and 980 nm due to the transition of xenon, which causes problems such as malfunctions and malfunctions of home appliance remote controls. A layer that absorbs light of 800 to 1000 nm and a film provided with the layer are laminated (Patent Document 4).

  An antireflection film that imparts such a near-infrared absorbing function to the hard coat layer has also been proposed (Patent Document 5). However, the method such as Patent Document 4 is a lamination of films imparted with individual functions of antireflection, electromagnetic wave shielding, and near infrared absorption. There is a problem of reduction and cost increase.

The method described in Patent Document 5 has been proposed as a means for solving the above problem, but is insufficient from the viewpoint of reducing the interference fringes and preventing the reflection of external light.
JP 2002-241527 A JP-A-8-197670 JP 2003-205563 A Japanese Patent Laid-Open No. 11-12604 JP 2006-201443 A

  An object of this invention is to eliminate said problem in the polyester film which laminated | stacked the hard-coat layer. That is, interference fringes are reduced, coloring of surface reflected light after antireflection processing is reduced, and when used for a front filter of a plasma display television, an antireflection effect and a near infrared absorption effect can be imparted. It is to provide an antireflection film.

As a result of intensive studies to achieve this goal,
(1) A hard coat layer is laminated on at least one surface of the polyester film, and the arithmetic average roughness Sa is 15 nm or more and less than 150 nm in the three-dimensional surface roughness parameter of the hard coat surface, and the surface height distribution is sharp Sku is 1 or more and 3 or less, light transmittance at a wavelength of 820 to 1000 nm is 30% or less, and has a protruding structure on the polyester film surface at the hard coat layer / polyester film interface, and immediately below the concave portion of the hard coat surface A hard coat film characterized by having a structure in which convex portions on the surface of the polyester film are present,
(2) The hard coat film according to the above (1), wherein the hard coat layer is a layer formed by thermosetting,
(3) The hard coat film is a layer formed from a polyfunctional acrylate, and the hard coat film as described in (1) or (2) above (4) The polyester film contains an ultraviolet absorber. The hard coat film according to any one of (1) to (3) above,
(5) The hard coat film as described in any one of (1) to (4) above, wherein the coat layer contains a near-infrared absorber.
(6) The hard coat film as described in (5) above, wherein the near-infrared absorber is a tungsten oxide composition,
(7) A high refractive index layer having a refractive index of 1.55 or more and a low refractive index layer having a refractive index of 1.40 or less are provided in this order on the hard coat layer described in (1) to (6) above. Anti-reflection film,
Is found.

  Since the hard coat film of the present invention has the above-described configuration, interference fringes are reduced, coloring of surface reflected light after antireflection processing is reduced, and furthermore, it has a near infrared absorption function, so that it can be used for display, etc. When it is applied to, it becomes excellent in visibility, and when used in a front filter of a plasma display, it has an effect of preventing reflection and is excellent in visibility, and it is possible to prevent an obstacle caused by near infrared rays.

  In the present invention, a hard coat layer having a concavo-convex structure on the surface is laminated on at least one surface of the polyester film, and the arithmetic average roughness Sa is 15 nm or more and less than 150 nm in the three-dimensional surface roughness parameter of the hard coat surface. Further, the point height Sku of the surface height distribution is 1 or more and 3 or less, and the light transmittance at a wavelength of 820 to 1000 nm is 30% or less.

  Examples of the polyester of the base polyester film in the present invention include polyethylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, and polypropylene naphthalate, and two or more of these may be mixed. Further, it may be a polyester in which these and other dicarboxylic acid components or diol components are copolymerized. In this case, in the film in which the crystal orientation is completed, the crystallinity is preferably 25% or more, more preferably Is preferably 30% or more, more preferably 35% or more. When the crystallinity is less than 25%, dimensional stability and mechanical strength tend to be insufficient. The crystallinity can be obtained by a density gradient method (JIS-K7112 (1980)) or a Raman spectrum analysis method.

  When the above-described polyester is used, its intrinsic viscosity (measured in o-chlorophenol at 25 ° C. according to JIS K7367) is preferably 0.4 to 1.2 dl / g, more preferably 0.5 to 0.8 dl / g.

  The polyester 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 can be exemplified, and the inner layer portion and the surface layer portion are chemically separated. Different polymers or the same kind of polymers may be used. When used for a display which is the intended use of the present invention, it is preferable that the polyester film does not contain particles or the like from the viewpoint of optical properties such as transparency without internal scattering.

  In the present invention, the polyester film has sufficient thermal stability, particularly dimensional stability and mechanical strength, and from the viewpoint of improving the flatness, it is crystallized by biaxial stretching in a state where a hard coat layer is provided. An oriented film is preferred. The crystal orientation by biaxial stretching means that the thermoplastic resin film before the crystal orientation is completed is stretched about 2.5 to 5 times in the longitudinal direction and / or the width direction, and then the crystal orientation is completed by heat treatment. Which shows a biaxially oriented pattern by wide-angle X-ray diffraction.

  The thickness of the polyester film used in the present invention is appropriately selected according to the use for which the hard coat film of the present invention is used, but from the viewpoint of mechanical strength and handling properties, it is preferably 10 to 500 μm, more preferably. Is 20 to 300 μm.

  The polyester 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, ultraviolet absorbers, organic and inorganic particles (for example, silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate, barium sulfate, carbon black, zeolite, titanium oxide, Metal fine powders), pigments, dyes, antistatic agents, nucleating agents, acrylic resins, polyester resins, urethane resins, polyolefin resins, polycarbonate resins, alkyd resins, epoxy resins, urea resins, phenol resins, silicone resins, rubber resins , Wax composition, melamine crosslinking agent, oxazoline crosslinking agent, methylolated, alkylolized urea crosslinking agent, acrylamide, polyamide, epoxy resin, isocyanate compound, aziridine compound, various silane coupling agents, various titanates And the like can be mentioned system coupling agent.

  Particularly when used for a plasma display, the polyester film preferably has an ultraviolet cut function and preferably contains an ultraviolet absorber in order to use a dye having a color correction function and a near infrared cut function.

  Preferred examples of the ultraviolet absorber include salicylic acid compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, benzoxazinone compounds, cyclic imino ester compounds, and the like. Of these, benzoxazinone compounds are most preferred from the viewpoints of UV-cutting property and color tone. These compounds may be used alone or in combination of two or more. Moreover, combined use of stabilizers, such as HALS (hindered amine light stabilizer) and antioxidant, is more preferable.

  Examples of benzoxazinone-based compounds that are preferable materials include 2-p-nitrophenyl-3,1-benzoxazin-4-one and 2- (p-bezoylphenyl) -3,1-benzoxazine-4. -One, 2- (2-naphthyl) -3,1-benzoxazin-4-one, 2-2'-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 '-( 2,6-naphthylene) bis (3,1-benzoxazin-4-one) and the like can be exemplified. The amount of these compounds added is preferably 0.5 to 5% by weight, preferably 1 to 5% by weight, in the base film.

  Further, it is preferable to use a cyanoacrylate-based tetramer compound in combination in order to impart further excellent light resistance. The cyanoacrylate tetramer compound is preferably contained in the base film in an amount of 0.05 to 2% by weight. The cyanoacrylate-based tetramer compound is a compound based on a tetramer of cyanoacrylate, such as 1,3-bis (2′cyano-3,3-diphenylacryloyloxy) -2, 2-bis-. (2 ′ cyano-3,3-diphenylacryloyloxymethylpropane) and the like can be exemplified. When using together with this, it is suitable to add 0.3 to 3 weight% of the above-mentioned ultraviolet absorber in a base film.

  It is desirable that the hard coat film of the present invention by adding the above ultraviolet absorber has a transmittance at a wavelength of 380 nm of 5% or less, preferably 3% or less. It is possible to protect the base film and dye pigment. The transmittance is 380 nm with a spectrophotometer U-3410 (manufactured by Hitachi, Ltd.) and an integrating sphere 130-063 (manufactured by Hitachi, Ltd.) having a diameter of 60 mm and a 10 degree tilt spacer attached. The transmittance is obtained.

 The hard coat film of the present invention has a total light transmittance of 90% or more, preferably 92% or more, more preferably 94% or more. When the total light transmittance is less than 90%, the sharpness of the image may be hindered when the antireflection film is used.

  In the hard coat film of the present invention, a hard coat layer having a concavo-convex structure is laminated on at least one surface of a polyester film, and the arithmetic average roughness Sa is 15 nm or more and 150 nm in the three-dimensional surface roughness parameter of the hard coat surface. The point height Sku of the surface height distribution is 1 or more and 3 or less.

Here, the three-dimensional surface roughness of the hard coat surface is 5 times with the surface shape measuring device SP-500 (manufactured by Toray Engineering Co., Ltd., which can simultaneously measure the interface shape and the surface shape in a non-destructive manner). It is obtained from the three-dimensional surface shape of the hard code surface obtained when measuring with the objective lens and the measurement mode WSI. The 3D surface roughness parameters of the hard coat surface defined by the present invention, the arithmetic average roughness Sa and the surface height distribution Sku, are the 3D surface shape measured by SP-500 in nanoscale 3D. This is a value obtained by analysis using the image processing software SPIP ^™ (Image Metrology A / S).

  Specifically, the arithmetic average roughness Sa is obtained by expanding two-dimensional Ra to three dimensions, and dividing the volume of the portion surrounded by the surface shape curved surface and the average surface by the measurement area. It can be obtained from the following formula. If the surface is the XY plane, the height direction is the Z axis, and the measured surface shape curve is the k-th x value and the l-th y value is z (xk, yl),

It is. Further, μ is an average surface obtained from the following formula.

Furthermore, the sharpness Sku of the surface height distribution is a measure of the sharpness of the surface shape curved surface, and characterizes the spread of the surface height distribution, and is defined by the following equation.

Sq is a two-dimensional Rq (RMS) extended to three dimensions, which represents the standard deviation σ in statistics. It is the root mean square deviation obtained by dividing the volume between the surface shape curved surface and the mean surface by the square and the volume of the portion sandwiched by the mean surface by the measured area and then obtaining the square root.

    When Sku = 3, it represents a normal distribution. When Sku <3, the surface height distribution is crushed. When Sku> 3, it is sharp. Represents.

  In the present invention, the arithmetic average roughness Sa of the three-dimensional surface roughness parameter of the hard coat layer surface is 15 nm or more and less than 150 nm, preferably Sa is 20 nm or more and 100 nm or less, more preferably 30 nm or more and 70 nm or less. Further, the edge height Sku of the surface height distribution is 1 or more and 3 or less, preferably 1.5 or more and 2.5 or less. If Sa is less than 15 nm, the surface of the hard coat layer is too smooth, resulting in uneven color in the surface reflected light after antireflection processing, resulting in poor appearance. On the other hand, when Sa is 150 nm or more, the reflected light from the hard coat surface is scattered, resulting in white turbidity or large transmission image scattering, resulting in a decrease in sharpness.

  Here, Sku is not theoretically less than 1. On the other hand, when the ratio is larger than 3, since the surface has sparsely formed sharp protrusions, visible color unevenness occurs in the reflected light after antireflection processing, resulting in poor appearance.

  The haze value specified by JIS K7136 of the hard coat film of the present invention is less than 3%, preferably 2% or less, more preferably 1% or less. If the haze is 3% or more, the visibility and clarity of the transmitted image may be deteriorated.

  Means for achieving the shape (Sa, Sku) of the hard coat surface, which is a feature of the present invention, includes a method of forming only the surface of the hard coat layer using a mold, the refractive index of the coating film, and the thickness of the coating film. Although there is a method of adding approximate organic particles to the coating film, etc., in the present invention, the method of providing a hard coat layer in the polyester film manufacturing process is most used from the viewpoint of shape imparting property, cleanness, and economical efficiency. preferable. According to this method, a concavo-convex structure is formed at the interface between the polyester film and the hard coat layer, and the surface shape of the hard coat layer reflecting it can be controlled. Furthermore, the surface shape can be controlled by optimizing the viscosity of the coating liquid and the heat history during curing of the coating liquid.

  When a concavo-convex structure is present at the interface between the hard coat layer and the polyester film, interference fringes due to interference of reflected light between the hard coat layer surface and the hard coat layer / substrate interface, which has been conventionally generated, can be reduced. In other words, the protrusions present on the interface can subdivide the area of the interface where light having the same optical path difference is reflected, and the interference fringes are reduced by subdividing the interference pattern to the invisible region.

  The height of the protrusions (convex portions) of the concavo-convex structure at the interface between the hard coat layer and the polyester film is preferably 2 μm or less, more preferably 1 μm or less, and still more preferably 0.7 μm.

  If the height of the protrusion is larger than 2 μm, the surface of the hard coat layer is excessively rough or the transmission image is glaring, which is not preferable. The protrusion height described here is the maximum height Rz (JISB0601: '01) in the interface shape curve. This can be determined by the method described later.

  Furthermore, in the present invention, as described above, the surface of the hard coat layer has specific Sa and Sku values, but having such an uneven structure on the surface of the hard coat layer has an effect of reducing interference fringes. In addition, the antireflection layer further laminated on the hard coat surface layer has the effect of reducing the coloration of reflected light and reducing color unevenness. The protrusions present on the hard coat surface are effective for generating fine unevenness in the thickness of the antireflection layer, thereby reducing the wavelength dependence of the reflected light intensity.

  In the present invention, an adhesive layer such as polyester, acrylic or polyurethane may be interposed between the polyester film and the hard coat layer as necessary, but it maintains adhesion under humid heat and reduces interference fringes. For this purpose, it is preferable not to interpose an adhesive layer.

  In the present invention, at the interface between the hard coat layer and the polyester film, the polyester film surface has a concavo-convex structure, and the hard coat surface shape in the cross-sectional direction of the convex part of the concavo-convex structure is a concave part. Here, the cross-sectional direction means a direction perpendicular to the film surface.

  Specifically, as shown in FIG. 1, the concave portion of the surface roughness curve of the hard coat film is in agreement with the convex portion of the roughness curve of the polyester film and hard coat layer interface in the cross-sectional direction. is there.

  A state in which the concave portion of the surface roughness curve of the hard coat film is coincident with the convex portion of the roughness curve at the interface between the polyester film and the hard coat layer immediately below cannot be obtained by the conventional coating method. The method described in the present invention can be obtained by a method of applying a hard coat layer forming coating solution in the middle of the film forming process, and it is possible to obtain both improvement in productivity and reduction of environmental burden by reducing the number of processes.

  Furthermore, since the concave and convex portions are matched, the deterioration of the transmission image may be reduced.

  As a method for confirming such a structure, a cross section of the film is cut out, and a shape line on the surface of the hard coat layer and a shape line at the interface between the polyester film and the hard coat layer are obtained by microscopic observation. Toray Engineering Co., Ltd.) can be used to measure the surface and interface roughness curves at the same time. From the point of measurement accuracy, surface shape measuring device SP-500 (Toray Engineering Co., Ltd., interface shape and The best method is to confirm the structure using a non-destructive measurement of the surface shape at the same time.

  In the present invention, it is preferable that the interface between the hard coat layer and the thermoplastic film is moderately rough, but as a means for roughening the interface, before forming the hard coat layer, an embossing roll or the like is used. A method of forming a desired surface using an embossing roll or the like before uniaxial stretching or biaxial stretching of the film production process, or generating cracks on the film surface during stretching of the thermoplastic film before completion of stretching orientation Examples include a method of applying a hard coat layer forming coating solution and forming protrusions at the interface in the stretching step. Among these, a method of forming a desired surface using an embossing roll or the like before uniaxial stretching or biaxial stretching of the film production process, or cracking the film surface during stretching of the thermoplastic film before completion of stretching orientation is preferred. It is a method of applying a hard coat layer forming coating liquid to be generated and forming protrusions at the interface in the stretching step, more preferably a hard coat layer forming coating liquid that generates cracks during stretching in the thermoplastic film before completion of stretching orientation. It is a method of applying and forming protrusions at the interface in the stretching process.

  Further, for the purpose of achieving the shape (Sa, Sku) of the hard coat surface, which is a feature of the present invention, the leveling property of the uncured coating film surface is improved between the coating of the hard coating layer forming coating liquid and the curing of the coating film. In order to adjust, leveling property can be lowered by lowering the temperature during stretching, or leveling property can be improved by providing a heating leveling zone.

  Although what is necessary is just to determine the thickness of a hard-coat layer according to a use, 0.5 micrometers-30 micrometers are preferable normally, More preferably, they are 1 micrometer-15 micrometers. When the thickness of the hard coat layer is less than 0.5 μm, even if it is sufficiently cured, the surface hardness is not sufficient because it is too thin, and the surface tends to be scratched. On the other hand, when the thickness exceeds 30 μm Tends to curl at the time of curing or cracks in the cured film due to stress such as bending.

  The hard coat film having such a structure can be produced by the following method.

  First, the hard coat layer forming composition laminated on at least one surface of the polyester film is composed of, for example, acrylic, urethane, urethane acrylate, melamine, organic silicate compound, silicone, and metal oxide. It is. Among these, an acrylic type that is cured by heat or actinic radiation is preferable, and a cured composition composed of a compound containing polyfunctional acrylate as a main component is preferable. Here, the ratio of the main component to the entire hard coat layer is 50% by weight or more, preferably 70% by weight or more. The polyfunctional acrylate is a monomer, oligomer or prepolymer having 3 (more preferably 4, more preferably 5) or more (meth) acryloyloxy groups in one molecule, and 3 in one molecule. More than one (meth) acryloyloxy group (in the present specification, "... (meth) acryl ..." means "... acrylic ... or ... metaacryl ...") Monomer, oligomer, and prepolymer. Examples of such a composition include compounds in which the hydroxyl group of a polyhydric alcohol having 3 or more alcoholic hydroxyl groups in one molecule is an esterified product of 3 or more (meth) acrylic acids. Can do.

  Specific examples include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, etc. Can be used. These may be used alone or in combination of two or more.

  The use ratio of the monomer, oligomer or prepolymer having 3 or more (meth) acryloyloxy groups in one molecule is preferably 50 to 90% by weight, more preferably based on the total amount of the constituent components of the hard coat layer. Is 50 to 80% by weight.

In addition to the above compounds, it is preferable to use one or two functional acrylates in combination for the purpose of relaxing the rigidity of the hard coat layer, relaxing shrinkage during curing, or adjusting the viscosity of the coating liquid.
The monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule can be used without particular limitation as long as it is a normal monomer having radical polymerizability.

As the compound having two ethylenically unsaturated double bonds in the molecule, the following (a) to (f) (meth) acrylates and the like can be used. That is,
(A) C2-C12 alkylene glycol (meth) acrylic acid diesters: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, etc.
(B) (Meth) acrylate diesters of polyoxyalkylene glycol: diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, etc.
(C) Polyhydric alcohol (meth) acrylic acid diesters: pentaerythritol di (meth) acrylate, etc.
(D) (Meth) acrylic acid diesters of ethylene oxide and propylene oxide adducts of bisphenol A or bisphenol A hydride: 2,2′-bis (4-acryloxyethoxyphenyl) propane, 2,2′-bis ( 4-acryloxypropoxyphenyl) propane, etc.
(E) Two or more in a molecule obtained by reacting a terminal isocyanate group-containing compound obtained by reacting a diisocyanate compound and two or more alcoholic hydroxyl group-containing compounds in advance with an alcoholic hydroxyl group-containing (meth) acrylate. Urethane (meth) acrylates having a (meth) acryloyloxy group, and the like, and
(F) Epoxy (meth) acrylates having two or more (meth) acryloyloxy groups in the molecule obtained by reacting a compound having two or more epoxy groups in the molecule with acrylic acid or methacrylic acid.

  Compounds having one ethylenically unsaturated double bond in the molecule include methyl (meth) acrylate, ethyl (meth) acrylate, n- and i-propyl (meth) acrylate, n-, sec-, and t. -Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, polyethylene glycol Mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, N-hydroxyethyl (meth) acrylamide, N-vinylpyrrolidone, - vinyl-3-methylpyrrolidone, or the like can be used N- vinyl-5-methyl pyrrolidone. These monomers may be used alone or in combination of two or more.

  The use ratio of the monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule is preferably 10 to 40% by weight, more preferably 20 to 20% by weight based on the total amount of the constituent components of the hard coat layer. 40% by weight. Acrylic oligomers are those in which a reactive acrylic group is bonded to an acrylic resin skeleton, such as polyester acrylate, urethane acrylate, epoxy acrylate, and polyether acrylate. In addition, a rigid skeleton such as melamine or isocyanuric acid is used. Those having an acrylic group bonded thereto can also be used.

The viscosity of the coating material composed of these materials is preferably 1000 to 5000 mPa · s (25 ° C.), and 50 to 200 mPa · s (100 ° C.) when heated. In particular, when the viscosity during heating (100 ° C.) is 50 to 200 mPa · s, the shape of the HC surface can be easily controlled.
When the viscosity of the coating liquid at heating (100 ° C.) is less than 50 mPa · s, the fluidity of the coating liquid is too high, so that the surface reflects the uneven structure of the hard coat (HC) -base material interface. May not be possible and may become flattened. Also, if the viscosity of the coating liquid at the time of heating (100 ° C.) is larger than 200 mPa · s, the fluidity of the coating liquid is too low, so a long leveling time must be provided to obtain the desired surface shape, and production May decrease. The viscosity of the coating liquid described in the present invention is determined by an E-type viscometer. If there is a substance that volatilizes at 100 ° C. or less in the coating, the coating is heated at 100 ° C. for 10 minutes in an open system. It is a value obtained by measuring the viscosity of the residue obtained.

  Moreover, a reactive diluent can be used suitably. The reactive diluent is a coating agent medium that has a function of a solvent in the coating process as a medium of the coating agent, and has a group that itself reacts with a monofunctional or polyfunctional acrylic oligomer. It will be.

  Specific examples of these acrylic oligomers, reactive diluents, and the like can be found in Shinzo Yamashita, Tosuke Kaneko, “Crosslinking Agent Handbook”, published in Taiseisha 1981, pages 267 to 275, pages 562 to 593. Can be referred to. Commercially available polyfunctional acrylic cured paints include Mitsubishi Rayon Co., Ltd. (trade name “Diabeam” series, etc.), Nagase Sangyo Co., Ltd. (trade name “Denacol” series, etc.), Shin-Nakamura Co., Ltd .; (Product name “NK Ester” series, etc.), Dainippon Ink and Chemicals Co., Ltd .; (Product name “UNIDIC” series, etc.), Toa Gosei Chemical Industries Co., Ltd. (product name “Aronix” series, etc.), Nippon Oils and Fats Co., Ltd. (Trade name “Blemmer” series, etc.), Nippon Kayaku Co., Ltd .; (trade name “KAYARAD” series, etc.), Kyoeisha Chemical Co., Ltd .; (trade names “light ester” series, “light acrylate” series, etc.) The product can be used.

  In the present invention, as a modifier for the hard coat layer, a coating property improver, an antifoaming agent, a thickener, an antistatic agent, inorganic particles, organic particles, an organic lubricant, an organic polymer compound, an ultraviolet ray, Absorbers, light stabilizers, dyes, pigments or stabilizers can be used, and these are used as a composition component of the coating layer constituting the hard coat layer within a range that does not impair the reaction due to active rays or heat, The properties of the hard coat layer can be improved depending on the application.

  In the present invention, it is necessary to contain a near-infrared absorber in the hard coat layer and to uniformly set the light transmittance at a wavelength of 820 to 1000 nm to 30% or less. By providing this function in the hard coat layer, there is no need to newly provide a near-infrared absorbing film, which is advantageous in terms of productivity and cost. Such near-infrared absorbers include azo, aminium, anthraquinone, cyanine, diimonium, dithiol metal complex, squarylium, naphthalocyanine, phthalocyanine, tungsten oxide, titanium oxide, zirconium oxide. Tantalum oxide, niobium oxide, zinc oxide, indium oxide, tin-doped indium oxide, tin oxide, antimony-doped tin oxide, cesium oxide, zinc sulfide, and the like. Among these, when it is contained in the hard coat layer, it is easily affected by ultraviolet rays of external light, so it has a high near-infrared absorbing ability, excellent light resistance and durability, and excellent transparency in the visible light region. Tungsten oxide compounds are preferred, and cesium-containing tungsten oxide is more preferred.

  In the present invention, as a method of curing the above hard coat composition, for example, a method of irradiating ultraviolet rays as active rays, a high temperature heating method, or the like can be used. It is desirable to add a photopolymerization initiator or a thermal polymerization initiator to the composition.

  Specific examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, methylbenzoyl formate, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2, Carbonyl compounds such as 2-dimethoxy-2-phenylacetophenone and 1-hydroxycyclohexyl phenyl ketone, tetramethylthiuram monosulfide, tetramethylthio Sulfur compounds such as uranium disulfide, thioxanthone, 2-chlorothioxanthone, and 2-methylthioxanthone can be used. These photopolymerization initiators may be used alone or in combination of two or more. Moreover, as a thermal polymerization initiator, a peroxide compound such as benzoyl peroxide or di-t-butyl peroxide can be used.

  The amount of the photopolymerization initiator or thermal polymerization initiator used is suitably 0.01 to 10 parts by mass with respect to 100 parts by mass of the hard coat layer forming composition. When an electron beam or gamma ray is used as a curing means, it is not always necessary to add a polymerization initiator. Further, when thermosetting at a high temperature of 200 ° C. or higher, it is not always necessary to add a thermal polymerization initiator.

  The hard coat layer forming composition used in the present invention has a thermal polymerization prevention such as hydroquinone, hydroquinone monomethyl ether or 2,5-t-butyl hydroquinone in order to prevent thermal polymerization during production and dark reaction during storage. It is desirable to add an agent. The addition amount of the thermal polymerization inhibitor is preferably 0.005 to 0.05% by weight with respect to the total weight of the hard coat layer forming composition.

  In the present invention, it is preferable to contain an isocyanate compound or a melamine-based crosslinking agent in the coating agent for forming the hard coat layer for the purpose of improving the adhesion with the polyester film and reducing the interference fringes observed from the hard coat layer surface. As the isocyanate compound, known compounds can be used. For example, 2,4- and / or 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate (abbreviated as MDI), polymeric MDI, 1,5 -Naphthylene diisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate (abbreviated as HDI), trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate (abbreviated as XDI), hydrogenated XDI, hydrogenated MDI, lysine diisocyanate, tri Examples thereof include monomers such as phenylmethane triisocyanate and tris (isocyanatephenyl) thiophosphate, and dimers or more. These may be used alone or in combination of two or more. The type of melamine crosslinking agent is not particularly limited, but melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, a compound partially or completely etherified by reacting a methylolated melamine with a lower alcohol, or These mixtures can be used. As the melamine-based crosslinking agent, a monomer, a condensate composed of a multimer of two or more, or a mixture thereof can be used.

  As the lower alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butanol, isobutanol and the like can be used. The functional group has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group in one molecule, and an imino group type methylated melamine, a methylol group type melamine, or a methylol group type methylated melamine. And fully alkyl methylated melamine. Of these, methylolated melamine and fully alkylated melamine are preferred in terms of adhesion and interference fringes-free. The amount of the isocyanate compound and the melamine-based crosslinking agent is not particularly limited, but it is 2 to 40% by weight, preferably 5 to 30% by weight in the solid content of the hard coat forming coating, and the balance of adhesion, hardness and interference fringe reduction. This is preferable.

In addition, it is preferable to use an acid catalyst in combination for the purpose of accelerating the curing of melamine. As the acid catalyst, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dimethyl pyrophosphoric acid, styrene sulfonic acid, and derivatives thereof (for example, blocking agent adducts such as dimethylethanolamine) can be preferably used. The amount of the acid catalyst added is 0.05 to 10% by weight, preferably 1 to 5% by weight, based on the melamine crosslinking agent. When a melamine-based crosslinking agent is added, it is particularly preferable to use a polyfunctional acrylate having at least one hydroxyl group as a preferred form of the coating composition in terms of improving adhesiveness.

  In forming the hard coat layer of the present invention, it is preferable to use a leveling agent to smooth the surface of the hard coat layer. Typical leveling agents include silicone-based, acrylic-based, and fluorine-based agents, but when only smoothness is required, silicone-based is effective with a small amount of addition. As the silicone leveling agent, polydimethylsiloxane as a basic skeleton and a polyoxyalkylene group added thereto (for example, SH190 manufactured by Toledo Corning Silicone Co., Ltd.) are suitable.

  In the case where a laminated film is further provided on the hard coat layer, it is necessary that the coating properties and adhesiveness of the laminated film are not inhibited. In that case, it is preferable to use an acrylic leveling agent. As such a leveling agent, “ARUFON-UP1000 series, UH2000 series, UC3000 series (trade name): manufactured by Toagosei Co., Ltd.” or the like is preferably used. The leveling agent is preferably added in an amount of 0.01 to 5% by weight in the hard coat layer forming composition.

  In addition, the hard coat film of the present invention can be obtained by laminating the hard coat layer by interposing an adhesive layer as necessary on the protrusion forming surface side of the thermoplastic film. It is effective to use the following method in order to directly adhere the hard coat layer without reducing the interference fringes and to reduce the coloring and uneven coloring of the reflected light during the antireflection processing.

  Specifically, the melt-extruded polyester sheet is cast on a cooling mirror drum at about 20 ° C. using a static electricity application method, then preheated with a preheating roll, uniaxially stretched in the longitudinal direction, and crystal orientation is not yet achieved. The hard coat composition coating is applied to the cast drum contact surface side of the polyester film that is complete. Thereafter, the film is drawn into the tenter while gripping the end portion and slightly stretched 1.1 to 1.3 times in the direction perpendicular to the longitudinal direction just before the film temperature just before the end of the preheating step exceeds the glass transition point of the film, and then the film When the temperature exceeds the glass transition point of the film, the film is stretched 2.5 to 3.5 times, and low-temperature heat setting (leveling zone) is required at a temperature that does not cure the coating film (140 to 180 ° C). In accordance with the above, further, high-temperature heat fixation at 200 ° C. or higher is continuously performed, and active ray irradiation treatment is performed as necessary. Using the above method, the hard coat layer surface roughness Sa and the sharpness Sku are adjusted to be within the scope of the present invention. Specifically, the surface of the hard coat layer can be adjusted by appropriately adjusting the coating liquid viscosity characteristics, the film forming temperature, and the treatment time according to the film forming speed.

  The laminated polyester film of the present invention thus obtained can be provided with a hard coat layer all at once in the film forming process, so that the productivity is good, the surface hardness is high, the wear resistance is excellent, the hard coat layer and Since the adhesiveness with the base film is excellent and the interference fringes are suppressed and the visibility is excellent, it can be used in a wide range of applications. In particular, it is suitably used as an antireflection film substrate for displays, a substrate for touch panels and the like.

  Various coating methods such as a reverse coating method, a gravure coating method, a rod coating method, a bar coating method, a die coating method, or a spray coating method can be used as a means for applying the hard coat layer forming coating agent.

  Examples of the active rays used as necessary 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.). Ultraviolet light is convenient and preferred. 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. Furthermore, the electron beam system is advantageous in that the apparatus is expensive and needs to be operated under an inert gas, but it is not necessary to include a photopolymerization initiator or a photosensitizer in the coating layer. is there.

  As the heat necessary for the thermosetting used in the present invention, steam heater, electric heater, infrared heater or far-infrared heater is used. The heat given by spraying on the base material and the coating film using is used. Among them, heat by air heated to 200 ° C. or higher is preferable, more preferably heat by nitrogen heated to 200 ° C. or higher. It is preferable because the curing rate is high. In addition, the laminated polyester film of the present invention can be used by being bonded to various functional films by various methods, and an adhesive layer can be laminated on the other surface or a conductive layer can be provided.

  For example, the opposite surface of the laminated polyester film of the present invention on which the hard coat layer is provided is bonded to a counterpart material using various adhesives, and the hard coat layer such as wear resistance and scratch resistance is attached to the counterpart material. It can also be used with a function. The pressure-sensitive adhesive used at this time is not particularly limited as long as it is a pressure-sensitive adhesive (adhesive) that adheres two objects by its pressure-sensitive action, and is a pressure-sensitive adhesive made of rubber, acrylic, silicone or polyvinyl ether. (Adhesive) can be used.

  Furthermore, the pressure-sensitive adhesive is roughly classified into two types, a solvent-type pressure-sensitive adhesive and a solventless pressure-sensitive adhesive. Solvent-type pressure-sensitive adhesives excellent in dryness, productivity, and processability are still mainstream, but in recent years, they are changing to solvent-free pressure-sensitive adhesives in terms of pollution, energy saving, resource saving, safety, and the like. Among these, it is preferable to use an actinic radiation curable pressure sensitive adhesive that is a pressure sensitive adhesive that is cured in seconds by irradiation with actinic radiation and has excellent properties such as flexibility, adhesion, and chemical resistance.

  Specific examples of the actinic radiation curable acrylic pressure-sensitive adhesive can be referred to the Japan Adhesive Society, “Adhesive Data Book”, published by Nikkan Kogyo Shimbun, 1990, pages 83 to 88. It is not limited to. Commercially available multifunctional acrylic UV curable paints, such as Hitachi Chemical Polymer Co., Ltd. (trade name “XY” series, etc.), Toho Kasei Kogyo Co., Ltd. (trade name “Hi-Rock” series, etc.), Three Bond Co., Ltd. ( Product names such as “Three Bond” series), Toa Gosei Chemical Industry Co., Ltd .; (Product name “Arontite” series, etc.), Cemedine Co., Ltd .; (Product name “Cemeloc Super” series, etc.) can be used. However, it is not limited to these.

  When this type of pressure-sensitive adhesive is applied to a normal biaxially stretched polyester film, the adhesiveness becomes insufficient, and various primer treatments, for example, a laminated film made of an acrylic resin, a polyester resin, a urethane resin, etc. are provided. Thereby, the adhesiveness of a polyester film and an adhesive layer can be improved.

  In the present invention, a hard coat layer can be formed on one side, and a primer layer for improving the adhesiveness with these pressure-sensitive adhesive layers can be formed on the opposite side. It goes without saying that when the coating solution containing the actinic radiation curable or thermosetting composition to be formed is applied, it may be applied to the back side of the coating solution at the same time, dried and optionally stretched.

  In addition, when the hard coat film of the present invention is used as an antireflection film for a plasma display or the like, it is preferably used by providing a high refractive index on the hard coat layer and further providing a low refractive index layer thereon. Can do.

  Although it does not specifically limit as a high refractive index layer, It is a thing with a refractive index of about 1.55-1.70, and it is preferable that a laminated thickness shall be 0.03-0.15 micrometer. Such a high refractive index layer can be obtained by finely dispersing metal compound particles in a binder component. The binder component is not particularly limited, and general-purpose resins such as polyester, acrylic, urethane, epoxy, and the hard coat component described in the present invention can be used. The metal compound particle itself has a high refractive index, and specifically includes tin-containing antimony oxide particles, zinc-containing antimony oxide particles, tin-containing indium oxide particles, zinc oxide / aluminum oxide particles, antimony oxide particles, and oxidation. Although titanium particles, zirconium oxide particles, and the like can be used, compounds capable of adding an antistatic function are more preferable, and tin-containing indium oxide particles are particularly preferable. The metal compound particles having an average primary particle diameter (sphere equivalent diameter according to the BET method) of 0.5 μm or less, preferably 0.001 to 0.3 μm, are preferable in terms of maintaining transparency. Organic conductive materials such as polypyrrole, polyaniline, and polythiophene can be added to these metal compounds for the purpose of further improving the conductivity.

  The low refractive index layer preferably has a refractive index of about 1.30 to 1.40, and the laminated thickness is preferably about 0.01 to 0.15 μm. As a material for forming the low refractive index layer, a known material can be applied, and a fluorine compound, a compound having a perfluoroalkyl group, and the like are preferable. It can also be achieved by filling hollow fine particles in the binder resin. Such hollow particles are disclosed, for example, in JP-A-2001-233611, J. Pat. AM. Chem. soc. 2003, 125, 316-317 and the like.

  The application method is not limited to application, but examples include microgravure coating, gravure coating, microgravure reverse coating, gravure reverse coating, die coating, comma coating, kiss coating, capillary coating, and wire bar coating. Among these, the micro gravure coat and the micro gravure reverse coat are preferable because the coating thickness accuracy is increased.

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

(1) Three-dimensional surface shape measurement, arithmetic mean surface roughness Sa and surface height distribution point Sku measurement, and polyester film-hard coat layer interface shape measurement Three-dimensional surface roughness measures the hard coat surface shape It is determined from the three-dimensional surface shape of the hard code surface measured with a 5 × objective lens and a measurement mode WSI with an apparatus SP-500 (manufactured by Toray Engineering Co., Ltd.) In addition, the 3D surface roughness parameters of the hard coat surface specified in the present invention, the arithmetic average roughness Sa and the surface height distribution Sku, are the nanoscale 3D images of the 3D surface shape measured by SP-500. This value is obtained by analysis using the processing software SPIP ^™ (Image Metrology A / S).

  Similarly, the shape measurement at the interface between the polyester film and the hard coat layer was also measured with a surface shape measuring device SP-500 (manufactured by Toray Engineering Co., Ltd.) with a 5 × objective lens and a measurement mode WSI. The shape of the “back surface” obtained by “Gaussian filter” − “high frequency cut” − “30 μm” is obtained.

  The obtained surface shape curve and interface shape curve were lined up and down to confirm the position of the unevenness.

  When seven or more concave portions on the surface correspond to ten convex portions on the interface, the convex portion on the surface of the polyester film is present immediately below the concave portion on the hard coat surface.

  The case where it is directly underneath was marked with ◯, and the case where it was not there was marked with ×.

  Further, Rz (according to JIS B0601: '01) of the obtained interface shape curve was defined as the height of the convex portion of the interface.

(2) Abrasion resistance The surface of the hard coat layer was changed with steel wool # 0000, and 10 reciprocations (speed: 10 cm / s) were rubbed under a constant load at each load, resulting in scratch resistance (no scratches). The maximum load that was present was measured. 2 kg / cm ² was a practically acceptable level and was accepted.

(3) Haze It measured based on JIS K-7136 using the direct reading haze computer by Suga Test Instruments Co., Ltd.

(4) Presence or absence of interference fringes After roughening the back surface of the measurement surface (hard coat layer surface side) with No. 240 sandpaper in the same way as measuring the surface reflectance and average waviness amplitude in order to eliminate the influence of back surface reflection The sample prepared by coloring with black magic ink is placed in a dark room 30 cm directly under a three-wavelength fluorescent lamp (National Parrook, three-wavelength daylight white (FL 15EX-N 15W)). Evaluation was made based on whether or not the iris pattern was visible when visually observed.

Iris pattern is not visible: A rank Very weak iris pattern is visible: B rank Weak rainbow pattern is visible: C rank Strong rainbow color pattern is clearly visible: D rank.

(5) Coloring and uneven coloring in reflected light after antireflection processing Paint containing tin-containing indium oxide particles (ITO) on the hard coat film surface (solid content 35.7%, polyfunctional urethane (meth) acrylate / ITO particles (Average primary particle size 30 nm) = 18/82) (Dai Nippon Paint Co., Ltd., EI-3) 3 parts by mass was dissolved in 10 parts by mass of n-butyl alcohol and 7 parts by mass of isopropyl alcohol. The coating solution obtained by stirring the mixture is coated on the surface of the hard coat layer using a wire bar, dried at 80 ° C., and then irradiated with ultraviolet light 1.0 J / cm ² to cure the coating layer. Thus, a high refractive index layer having a thickness of about 0.1 μm and a refractive index n = 1.682 was formed.

  Next, 40 parts by mass of a coating (solid weight 3%) containing a fluorine-containing copolymer (fluoroolefin / vinyl ether copolymer) (manufactured by JSR Corporation, JN-7215), colloidal silica dispersion (average primary particles) 13 parts diameter, solid content weight 30%, methyl isobutyl ketone dispersion 1 part by mass, colloidal silica dispersion (average primary particle size 100 nm, solids weight 30%, methyl isobutyl ketone dispersion) 0.1 part by weight Thus, the coating solution was adjusted. This coating solution is applied onto the conductive layer 4 using a wire bar, dried and cured at 150 ° C., and a low refractive index layer having a thickness of about 0.1 μm and a refractive index n = 1.42 is formed. Thus, an antireflection processed film was produced. Using the produced anti-reflection processed hard coat film, coloring of reflected light and coloring unevenness were evaluated by the same method as the above (4) method for evaluating the presence or absence of interference fringes.

Further, as an index of the degree of coloring, the reflectance curve of the hard coat film after antireflection processing is measured as described in (6), and the difference between the maximum value and the minimum value of the reflectance curve at a wavelength of 400 to 750 nm is measured. Measured, the value is less than 1%, there is little coloring: ○
1% or more and less than 2% is slightly colored:
2% or more is colored: ×
And ○ was accepted.

(6) Surface reflectance The surface reflectance was measured as follows.
The reflectance at an incident angle of 10 degrees was measured using a U-3410 type spectrophotometer equipped with a 60 mmφ integrating sphere manufactured by Hitachi.

  In order to eliminate the influence of reflection on the back surface of the measurement sample, after roughening the back surface of the measurement surface (hard coat layer surface side) with No. 240 sandpaper, the average visible light transmittance at a wavelength of 400 to 600 nm is 5% or less. It was colored with black magic ink. The determination of the presence or absence of the influence of the back surface reflection was judged to have no influence of the back surface reflection if the glossiness of the back surface after the treatment (incident angle 60 °, light receiving angle 60 °) was 10 or less. The glossiness was measured in accordance with JIS Z 8741 using a digital variable glossiness meter UGV-5B (manufactured by Suga Test Instruments Co., Ltd.).

(7) Visibility Affix the four corners with cellophane tape on the screen surface of a PDP TV (TH-42PX500: manufactured by Matsushita Electric Co., Ltd.) with the hard coat film cut out in A4 placed in a dark room. Images were projected on a television, and the transmitted images of the hard-coated film pasted part and the unpasted part were observed and compared from the position of 1.5 m in front of the television at a position of 45 degrees to examine the deterioration state of the transmitted image.

Transparent image looks clear with no deterioration: ◎
Transparent image is slightly blurred: ○
Transparent image is blurred and difficult to see:
Transparent images are not visible: x.

(8) Total light transmittance The total light transmittance of the hard coat film thickness direction was calculated | required using the fully automatic direct reading haze computer HGM-2DP (made by Suga Test Instruments Co., Ltd.), and it was set as the average value of 10-point measurement.

(9) Spectral transmittance of 380 nm, 820 nm, and 1000 nm A state in which a Φ60 integrating sphere 130-063 (manufactured by Hitachi, Ltd.) and a 10-degree tilt spacer are attached to a spectrophotometer U-3410 (manufactured by Hitachi, Ltd.) Then, 370 nm to 1100 nm were continuously measured at intervals of 5 nm, the transmittances of 380 nm, 820 nm, and 1000 nm were obtained, and the average value of each 10-point measurement was taken as the spectral transmittance (%) at each wavelength.

    Those having a spectral transmittance of 30% or less at 820 nm and 1000 nm were regarded as acceptable.

    However, when there was a spectral transmittance of 820 nm to 1000 nm that exceeded 30% at any wavelength, it was rejected.

    The spectral transmittance at 380 nm is preferably 5% or less, more preferably 3% or less.

  The same measurement was performed after the light resistance test described below, and the spectral transmittance after the light resistance test was measured in the same manner.

(10) Light resistance test Using an ultraviolet degradation acceleration tester iSuper UV Tester SUV-W131 (manufactured by Iwasaki Electric Co., Ltd.), a forced ultraviolet irradiation test was conducted under the following conditions, and the degree of deterioration after irradiation (yellowing degree) ) Was evaluated by the transmission b value.

"UV irradiation conditions"
Illuminance: 100 mW / cm ² , temperature: 60 ° C., relative humidity: 50% RH, irradiation time: 16 hours (11) Transmission b value Using a spectroscopic color difference meter SE-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) , And measured by the transmission method according to JIS-K-7105.

(12) Reflection suppression effect A4 size hard coat film is anti-reflective processed as described in (5) above, and the four corners on the screen surface of PDP TV (TH-42PX500: Matsushita Electric Co., Ltd.) with cellophane tape. Fix and paste. The interior lighting is set to 400 to 500 lx, and without turning on the TV, an image of himself / herself reflected on the front of the TV is observed from a distance of 1.5 m from the TV.

Compare the film affixed part and the unapplied part,
The outline of the observer's eyes cannot be seen: ◎
The outline of the observer's eyes can be seen somehow, but the map is not clear compared to the unattached case: ○
The outline of the observer's eyes can be visually recognized: x.

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

<H-1>
-Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (KAYARAD-DPHA: Nippon Kayaku Co., Ltd.) 70 parts by mass-Trimethylolpropane-Ethylene oxide modified triacrylate (M-350
: Toagosei Chemical Co., Ltd.) 10 parts by mass
・ 20 parts by mass of fully alkylated melamine (Cymel 303: manufactured by Nippon Cytec Co., Ltd.) ・ Catalyst: 1 part by mass of catalyst 602 (manufactured by Nippon Cytec Co., Ltd.) ・ Leveling agent: Alfon UP1000 (manufactured by Toagosei Co., Ltd.) ) 0.2 parts by mass, near infrared absorber: YMF-01 (manufactured by Sumitomo Metal Mining Co., Ltd.) (cesium-containing tungsten oxide content 10 wt% suspension) 300 parts by mass The above composition was mixed and heated (40 C.) Volatile substances were removed and adjusted by distillation under reduced pressure (3.2 kPa).

Coating liquid viscosity 25 ° C 2500 mPa · s
100 ° C. 200 mPa · s.

<H-2>
-40 parts by mass of a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (KAYARAD-DPHA: manufactured by Nippon Kayaku Co., Ltd.)-trimethylolpropane-ethylene oxide modified triacrylate (M-350
: Toagosei Chemical Co., Ltd.) 40 parts by mass
・ 20 parts by mass of fully alkylated melamine (Cymel 303: manufactured by Nippon Cytec Co., Ltd.) ・ Catalyst: 1 part by mass of catalyst 602 (manufactured by Nippon Cytec Co., Ltd.) ・ Leveling agent: Alfon UP1000 (manufactured by Toagosei Co., Ltd.) 0.2 parts by mass.
・ Near-infrared absorber: YMF-01 (manufactured by Sumitomo Metal Mining Co., Ltd.) (cesium-containing tungsten oxide content 10 wt% suspension) 300 parts by mass The above composition was mixed and heated (40 ° C.) under reduced pressure (3.2 kPa) ) Volatile substances were removed and adjusted by a distillation method.

Coating liquid viscosity 25 ° C 1000mPa · s
100 ° C. 80 mPa · s.

<H-3>
-20 parts by mass of a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (KAYARAD-DPHA: manufactured by Nippon Kayaku Co., Ltd.)-Trimethylolpropane-Ethylene oxide modified triacrylate (M-350
: Toagosei Chemical Co., Ltd.) 60 parts by mass
-20 parts by mass of fully alkylated melamine (Cymel 303: manufactured by Nippon Cytec Co., Ltd.)
Catalyst: Catalyst 602 (Nippon Cytec Co., Ltd.) 1 part by mass Leveling agent: Alfon UP1000 (Toa Gosei Chemical Co., Ltd. 0.2 part by mass)
・ Near-infrared absorber: YMF-01 (manufactured by Sumitomo Metal Mining Co., Ltd.) (cesium-containing tungsten oxide content 10 wt% suspension) 300 parts by mass The above composition was mixed and heated (40 ° C.) under reduced pressure (3.2 kPa) ) Volatile substances were removed and adjusted by a distillation method.

Coating liquid viscosity 25 ° C 800mPa · s
100 ° C. 60 mPa · s.

<H-4>
-Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (KAYARAD-DPHA: Nippon Kayaku Co., Ltd.) 70 parts by mass-Trimethylolpropane-Ethylene oxide modified triacrylate (M-350
: Toagosei Chemical Co., Ltd.) 10 parts by mass
・ 20 parts by mass of fully alkylated melamine (Cymel 303: manufactured by Nippon Cytec Co., Ltd.) ・ Catalyst: 1 part by mass of catalyst 602 (manufactured by Nippon Cytec Co., Ltd.) ・ Leveling agent: Alfon UP1000 (manufactured by Toagosei Co., Ltd.) ) 0.2 parts by mass, near infrared absorber: Nippon Kayaku Co., Ltd. "KAYASORB IRG-050"
29 parts by mass, a solution obtained by stirring and mixing 16 parts by mass of “EEX Color IR-10A” manufactured by Nippon Shokubai Co., Ltd. with 2000 parts by mass of methyl ethyl ketone 120 parts by mass The above composition was mixed and heated (40 ° C. ) Volatile substances were removed and adjusted by distillation under reduced pressure (3.2 kPa).

Coating liquid viscosity 25 ° C 2500 mPa · s
100 ° C. 200 mPa · s.

<H-5>
-Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (KAYARAD-DPHA: Nippon Kayaku Co., Ltd.) 70 parts by mass-Trimethylolpropane-Ethylene oxide modified triacrylate (M-350
: Toagosei Chemical Co., Ltd.) 10 parts by mass
・ 20 parts by mass of fully alkylated melamine (Cymel 303: manufactured by Nippon Cytec Co., Ltd.) ・ Catalyst: 1 part by mass of catalyst 602 (manufactured by Nippon Cytec Co., Ltd.) ・ Leveling agent: Alfon UP1000 (manufactured by Toagosei Co., Ltd.) ) 0.2 parts by mass The above composition was mixed, and volatile substances were removed and adjusted by heating (40 ° C.) and reduced pressure (3.2 kPa) distillation method.

Coating liquid viscosity 25 ° C 2000 mPa · s
100 ° C. 150 mPa · s.

<H-6>
Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (KAYARAD-DPHA: Nippon Kayaku Co., Ltd.) 70 parts by mass Polyethylene glycol diacrylate (M-250: manufactured by Toagosei Co., Ltd.) 5 Parts by mass
・ 20 parts by mass of fully alkylated melamine (Cymel 303: manufactured by Nippon Cytec Co., Ltd.) ・ Catalyst: 1 part by mass of catalyst 602 (manufactured by Nippon Cytec Co., Ltd.) ・ Leveling agent: Alfon UP1000 (manufactured by Toagosei Co., Ltd.) ) 0.2 parts by mass, near infrared absorber: YMF-01 (manufactured by Sumitomo Metal Mining Co., Ltd.) (cesium-containing tungsten oxide content 10 wt% suspension) 300 parts by mass The above composition was mixed and heated (40 C.) Volatile substances were removed and adjusted by distillation under reduced pressure (3.2 kPa).

Coating liquid viscosity 25 ° C 2800mPa · s
100 ° C. 230 mPa · s.

Example 1
A polyethylene terephthalate (PET) (extreme viscosity 0.65 dl / g) chip is sufficiently dried in vacuum at 180 ° C for 3 hours, then fed to an extruder and melted at 285 ° C, and then extruded into a sheet from a T-shaped die. It was wound around a mirror cast drum having a surface temperature of 20 ° C. by using an electrostatic application casting method, and cooled and solidified to obtain an unstretched sheet. At this time, the cooling time in the drum (drum contact time) was set to 2.5 seconds. The unstretched sheet thus obtained was preheated with a roll group heated to 75 ° C., and then stretched 3.2 times in the longitudinal direction at 95 ° C. The hard coat layer forming coating (H-1) was applied to the drum surface of the uniaxially stretched film to a thickness of 20 μm. The film was continuously guided into the tenter while gripping both ends of the film, preheated at 85 ° C. for 15 seconds, then slightly stretched 1.2 times in the width direction at 85 ° C., and 3.3 times in the width direction at 105 ° C. Stretching was performed. Thereafter, the coating was cured by passing through a leveling zone at 180 ° C. for 5 seconds and performing heat treatment for 25 seconds while relaxing 5% in the heat treatment zone at 235 ° C. continuously. Table 1 shows the evaluation results of the obtained film. The obtained film was excellent in surface hardness, almost free from interference fringes, good visibility, high near-infrared absorption effect, and almost no coloring and coloring unevenness after antireflection processing.

(Example 2)
A hard coat film was obtained in the same manner as in Example 1 except that H-2 was used as the hard coat layer-forming coating agent. The obtained film had excellent surface hardness, almost no interference fringes, good visibility, a high near-infrared absorbing effect, and good coloring and uneven coloring after antireflection processing.

(Comparative Example 1)
A hard coat film was obtained in the same manner as in Example 1 except that H-3 was used as the hard coat layer forming coating agent. The resulting film had almost no interference fringes, good visibility, and high near-infrared absorption effect, but the surface hardness was low, and this film had almost no interference fringes, but the coating viscosity was low. Since the liquid was used, the coating liquid leveled in a short time and the surface was smoothed. Therefore, the reflected light after antireflection processing was colored and uneven coloring was observed.

(Example 3)
A hard coat film was obtained in the same manner as in Example 1 except that the stretching temperature was 95 ° C. The obtained film had excellent surface hardness, almost no interference fringes, good visibility, a high near-infrared absorbing effect, and good coloring and uneven coloring after antireflection processing.

Example 4
In Example 1, a polyethylene terephthalate (hereinafter referred to as PET) (extreme viscosity 0.63 dl / g) chip to which 0.4 wt% of Siasolv 3638 (manufactured by Cytec Co., Ltd.) was added as an ultraviolet absorber was prepared in the same manner. A hard coat film was obtained.
The obtained film had excellent surface hardness, almost no interference fringes, good visibility, a high near-infrared absorbing effect, and good coloring and uneven coloring after antireflection processing. Furthermore, the amount of change in the b value after the light resistance test was the smallest.

(Comparative Example 2)
A polyethylene terephthalate (PET) (extreme viscosity 0.65 dl / g) chip is sufficiently dried in vacuum at 180 ° C for 3 hours, then fed to an extruder and melted at 285 ° C, and then extruded into a sheet from a T-shaped die. It was wound around a mirror cast drum having a surface temperature of 20 ° C. by using an electrostatic application casting method, and cooled and solidified to obtain an unstretched sheet. At this time, the cooling time in the drum (drum contact time) was set to 2.5 seconds. The unstretched sheet thus obtained was preheated with a roll group heated to 75 ° C., and then stretched 3.5 times in the longitudinal direction at 95 ° C. A non-drum surface of this uniaxially stretched film was coated with a 3 wt% water dilution of an aqueous polyurethane resin (Hydran AP-10: manufactured by Dainippon Ink & Chemicals, Inc.) using a # 6 wire bar. Both ends of the coated film were gripped and led to a preheating zone at 85 ° C., and stretched 3.5 times in the width direction in a heating zone at 110 ° C. Thereafter, a heat treatment was performed for 15 seconds while continuously performing a relaxation treatment of 5% in a heat treatment zone at 225 ° C. The polyurethane resin-coated surface of the 100 μm polyester film obtained was embossed by hot pressing (linear pressure 50 N / mm, temperature 120 ° C., speed 10 m / min) to provide irregularities on the film surface. As for the surface roughness of the obtained film, Sa was 120 nm. Embossed shape is grainy. On the surface provided with the irregularities, the H-1 hard coat-forming coating agent diluted to 50% with methyl isobutyl ketone was applied with 12 μm with a metabar, and after fixing the film, it was dried in an oven at 80 ° C. for 60 seconds, Immediately, it was cured by treatment in a hot air oven at 230 ° C. for 1 minute. The hard coat layer thickness was 5 μm.

  Although this film was excellent in abrasion resistance and had almost no interference fringes, the transmitted image was unclear because the uneven positions were not matched.

(Comparative Example 3)
In Example 1, a hard coat film was obtained in the same manner except that it was passed through a leveling zone at 180 ° C. for 15 seconds immediately after transverse stretching.

  The obtained hard coat film had a hard coat layer thickness of 5 μm.

 This film has excellent wear resistance and almost no interference fringes, but as described above, the hard coat layer surface is smoothed by passing through a long leveling zone before the coating is cured, and the reflected light after antireflection processing Was colored and uneven coloring was observed.

(Example 5)
A hard coat film was obtained in the same manner as in Example 1 except that H-4 was used as the hard coat layer forming coating agent.

  The obtained film had excellent surface hardness, almost no interference fringes, good visibility, a high near-infrared absorbing effect, and good coloration and coloring unevenness after antireflection processing. However, the ultraviolet absorption effect after the light resistance test was greatly reduced.

(Comparative Example 4)
In Example 1, as a hard coat forming coating material, a coating material of H-1 added with 1 part by mass of styrene-acrylic crosslinked organic particles having an average particle diameter of 5 μm and a particle refractive index of 1.52, It was produced in the same manner except that the preheating temperature was 100 ° C.

  Although this film was excellent in abrasion resistance and had almost no interference fringes, the surface was roughened by the addition of particles, and the uneven structure was not formed at the hard coat layer-PET interface, so visibility was deteriorated.

(Comparative Example 5)
In Comparative Example 4, the same procedure was used except that the hard coat forming coating material was an H-1 coating material added with 5 parts by mass of styrene-acrylic crosslinked organic particles having an average particle diameter of 5 μm and a particle refractive index of 1.52. Made.

  This film has excellent wear resistance and almost no interference fringes. Sex was getting worse.

(Comparative Example 6)
It was produced in the same manner as in Example 1 except that fine stretching after preheating was not performed.

  This film had excellent wear resistance, good visibility, and a high near-infrared absorption effect. However, since the film was not finely stretched, the interface uneven structure was not formed, and the surface was smoothed. Therefore, the reflected light after antireflection processing was colored and uneven coloring was observed.

(Comparative Example 7)
A hard coat film was obtained in the same manner as in Example 1 except that H-5 was used as the hard coat layer forming coating agent.
Although this film was excellent in abrasion resistance, interference fringes were severe, the reflected light after antireflection processing was colored, and uneven coloring was observed. There was no near infrared absorption function.

(Example 6)
A hard coat film was obtained in the same manner as in Example 1 except that the film was stretched 3.5 times in the longitudinal direction at 95 ° C., and immediately passed through the heat treatment zone at 235 ° C. immediately after transverse stretching. This film has excellent wear resistance, no interference fringes, and the hard coat layer surface is roughened before passing through the leveling zone before the coating is cured, and the reflected light after antireflection processing is colored and colored. Unevenness was not recognized.

(Example 7)
A hard coat film was obtained in the same manner as in Example 6 except that H-3 was used as the hard coat layer forming coating agent. This film has excellent wear resistance, no interference fringes, and the hard coat layer surface is roughened before passing through the leveling zone before the coating is cured, and the reflected light after antireflection processing is colored and colored. Unevenness was not recognized.

 The film of the present invention is a hard coat film that has excellent adhesion to the hard coat layer, hardly generates interference fringes, and is also excellent in light resistance, and is used for antireflection films for displays such as liquid crystal and plasma. It is useful as a substrate film for substrates, touch panels, window coverings, solar cell members, nameplates and the like.

Schematic of surface roughness curve and roughness curve of polyester film and hard coat layer interface

Claims (7)

A hard coat layer having an uneven structure is laminated on at least one surface of the polyester film,
In the three-dimensional surface roughness parameter of the hard coat layer surface,
Arithmetic mean roughness Sa is 15 nm or more and less than 150 nm,
And the surface height distribution sharp Sku is 1 or more, 3 or less, the light transmittance at a wavelength of 820 to 1000 nm is 30% or less, and has an uneven structure on the polyester film surface at the interface between the hard coat layer and the polyester film, and the uneven structure The hard coat film whose hard coat surface shape of the cross-sectional direction of a convex part is a recessed part. The hard coat film according to claim 1, wherein the hard coat layer is a layer formed by thermosetting. The hard coat film according to claim 1 or 2, wherein the hard coat layer is a layer formed of a polyfunctional acrylate. The hard coat film according to claim 1, wherein the polyester film contains an ultraviolet absorber. The hard coat film according to claim 1, further comprising a near infrared absorber in the hard coat layer. The hard coat film according to claim 5, wherein the near-infrared absorber is a tungsten oxide-based composition. A reflection characterized by providing a high refractive index layer having a refractive index of 1.55 or more and a low refractive index layer having a refractive index of 1.40 or less in this order on the hard coat layer according to claim 1. Prevention film.

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