JP2007223193A - Hard coat film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat film superior in adhesiveness, high in surface hardness and superior in abrasion resistance, is suppressed in the occurrence of an iris pattern, and superior in visibility, in a laminated film from a hard coat layer and a substrate film. <P>SOLUTION: On the hard coat film where the hard coat layer is laminated on at least one side of the substrate film, fine projections are formed on the surface of the hard coat layer side of the substrate film, an aspect ratio of the width and length of the projection is 1-10 and its height is 0.05-1 μm and the hard coat film comprises the hard coat layer containing a polyfunctional acrylate and a melamine type crosslinking agent as a main component and a curing composition containing a silicone type or a fluorine containing additive. Further, the hard coat film where an adhesive layer does not lie between the substrate film and the hard coat layer and has an average undulation amplitude of the reflectivity on the hard coat layer side at the wavelength of 400-600 nm of not more than 1.0% and all light transmittance of at least 80%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hard coat film, more specifically, the present invention has good permeability and anti-glare properties, excellent adhesion and wear resistance between the hard coat layer and the substrate, and almost no occurrence of interference fringes, Furthermore, it is related with the hard coat film excellent in the wipeability of dirt.

  Hard coat films in which a hard coat layer is provided on the surface of a polyester substrate are widely used for nameplate films, antireflection films, touch panel films, and the like.

  However, the normal polyester film has poor adhesion to the hard coat layer because the surface is highly crystallized, and the hard coat layer peels off from the base film, which is substantially inferior in durability. Has drawbacks. For this reason, conventionally, studies have been made on imparting adhesion to the surface of the polyester film by various methods.

  Conventionally, as a method for imparting adhesion to a polyester film, surface activation treatment by corona treatment or plasma treatment on the surface of the polyester base film, acid, acrylic resin on the film surface, sulfonate group-containing polyester resin or urethane resin A method of providing various resins such as a primer layer (see Patent Documents 1 to 3) is already known.

  In particular, a method (inline coating method) in which a coating liquid containing the above resin component is applied onto a base film by coating, dried, and then subjected to stretching and heat treatment to complete crystal orientation (in-line coating method) simplifies and manufactures the process. It is considered promising in terms of cost and is being actively conducted.

  However, the provided primer layer and the base polyester film often have different refractive indexes, and further, a refractive index difference between the hard coat layer and the primer layer occurs. For this reason, rainbow-colored irregularities (interference fringes) occur due to interference of light reflected from the interface, causing glare and partial iris reflection when viewed from a certain angle, and are extremely visible when used in display applications. Will be bad.

As a means for improving this phenomenon, there is a method of reducing the difference in refractive index between the substrate and the hard coat layer. As this method, a method of providing a primer layer having an intermediate refractive index between the substrate and the hard coat layer has been proposed. In this method, even if the intermediate layer is provided, the refractive index changes only in a stepwise manner, and the interference fringes are not reduced or eliminated. There is also a problem that it takes time since a process of providing an intermediate layer is required. (See Patent Document 4)
As another improvement method, a method for reducing interference fringes by applying a hard coating agent using a solvent that dissolves the base film and dissolving or swelling the base material is proposed (Patent Document 5). Has been.

  However, in the method of dissolving and swelling the base film, the applicable resin is limited, and a highly biaxially oriented polyester film is limited to a special solvent such as orthochlorophenol, and the working environment is extremely bad. In addition, the size of the concavo-convex structure to be formed is not mentioned, and even if interference fringes can be reduced, the haze increases and the low haze required for display applications cannot be obtained, resulting in poor visibility. .

  Further, in the case of using a hard coat film for display applications, prevention of reflection of external light (glare) on the screen has become an essential issue as the screen has been enlarged in recent years. Such a glare surface causes a significant loss of visibility of the screen. In the present invention, anti-glare means that the reflection of external light is diffused and diffused by irregularities on the surface of the anti-glare layer formed on the surface of the display or the like, or particles in the anti-glare layer, etc. This refers to the phenomenon of reflection on the screen.

In order to prevent such reflection of external light, glass or a plastic plate, or a surface of a plastic film roughened by some method is installed or stuck on the outermost surface of the screen. As another surface roughening technique, there is a method of performing mat coating containing a pigment such as metal particles on the film surface. (Patent Document 6)
However, the method of roughening the surface is inferior in permeability and antifouling property. If a hard-coating material is used as a binder, a scratch-resistant coating film can be obtained, but a large amount of particles is required to provide sufficient prevention of external light reflection (antiglare). Must be added. Therefore, as the antiglare property is gradually improved, the permeability is lowered. Furthermore, the addition of particles causes the particles to protrude from the surface and roughen the surface, so that it can wipe off dirt such as sebum that adheres to the surface or dust that enters the recesses on the surface (antifouling property). There were problems such as lowering.

In addition, when a hard coat film is used for a display application, it is exposed to an environment such as ultraviolet rays emitted from sunlight or a fluorescent lamp, or ultraviolet rays emitted by plasma emission, so that a polyester film deteriorated by ultraviolet rays is long-term. In use, there is a problem of yellowing or a decrease in strength. For display applications, colorless and transparent are required to obtain clear images. Furthermore, in the case of a plasma display, neon orange light and near infrared light centered around 600 nm are emitted from the principle of light emission, and dyes are used to correct or cut them. In order to prevent these deteriorations, it is extremely important to provide an ultraviolet absorbing function when the film is used as a front filter.
Japanese Patent Laid-Open No. 55-15825 JP 58-78761 A JP 60-248232 A JP 2000-111706 A JP 2003-205563 A JP-A-8-309910

  The present invention has the above disadvantages in the prior art, specifically, the generation of an iris pattern is suppressed, the antiglare property and transparency are excellent, the adhesion between the hard coat layer and the substrate is excellent, and dirt is easily wiped off. An object of the present invention is to provide a hard coat film in which deterioration due to ultraviolet rays is reduced.

In order to achieve this object, the present inventors have conducted intensive research and have found that the object can be achieved by the following means.
That is, the present invention is (1) In a hard coat film in which a hard coat layer is laminated on at least one side of a base film, fine protrusions are formed on the hard coat layer side surface of the base film, and the width and length of the protrusions are A hard coat film having an aspect ratio of 1 to 10 and a protrusion of 0.05 to 1 μm in height;
(2) The hard coat film according to (1), wherein the hard coat layer comprises a cured composition containing a polyfunctional acrylate and a melamine-based crosslinking agent as main components and a silicone-based or fluorine-based additive,
(3) In the hard coat film in which the hard coat layer is laminated on at least one surface of the base film, the average waviness amplitude of the reflectance on the hard coat layer side at a wavelength of 400 to 600 nm is 1% or less. (1) or the hard coat film according to (2),
(3) The hard coat film according to (1) or (2), wherein the hard coat layer comprises a cured composition mainly composed of a polyfunctional acrylate and a melamine-based crosslinking agent.
(4) The hard coat film according to any one of (1) to (3), wherein no adhesive layer is interposed between the base film and the hard coat layer,
(5) The hard coat film according to any one of (1) to (4), wherein the base film contains an ultraviolet absorber,
(6) The total light transmittance is 80% or more, the transmission b value is 1.5 or less, and the transmittance at 380 nm is 5% or less, according to any one of (1) to (5) Hard coat film,
(7) A hard coat film produced by an in-line coating method including a step of applying a hard coat coating agent on at least one side of a base film, providing a hard coat layer, and then stretching and curing in at least one direction. The hard coat film according to any one of (1) to (6),
It is.

  The hard coat film of the present invention has the above-described configuration, has small interference fringes, good antiglare properties and transparency, good adhesion between the substrate and the hard coat layer, excellent wiping of dirt, and ultraviolet rays. There is an effect that the deterioration due to the above is small. Furthermore, when used as a front filter member for a display or the like, it particularly has a function of preventing deterioration of the pigment.

  The hard coat film of the present invention has a structure in which a hard coat layer is laminated on at least one side of a base film.

  The base film in the present invention is a film that can be formed by melt film formation or solution film formation. Specific examples thereof include films made of polyester, polyolefin, polyamide, polyphenylene sulfide, triacetate and polycarbonate. Of these, a film made of a thermoplastic resin, particularly a polyester, particularly excellent in transparency, mechanical strength and dimensional stability, is preferably used.

  Examples of the polyester preferably used in the present invention include polyethylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, and polypropylene naphthalate, and a mixture of two or more of these may be used. 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 degree of crystallinity can be measured by 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 base film used in the present invention may be a composite film having a laminated structure of two or more layers. As the composite film, for example, a composite film that is substantially free of particles in the inner layer portion and provided with a layer containing particles in the surface layer portion, has coarse particles in the inner layer portion, and fine particles in the surface layer portion. And a composite film having a layer in which the inner layer portion contains fine bubbles. Further, the composite film may be a chemically different polymer or an identical polymer in the inner layer portion and the surface layer portion. When used for a display which is a particularly preferred application of the film of the present invention, it is preferable in terms of optical properties such as transparency that the substrate film does not contain particles.

  The base film in the present invention has sufficient thermal stability of the film, particularly dimensional stability and mechanical strength, and from the viewpoint of improving the flatness, in the state where the hard coat layer is provided, biaxial stretching is performed. A crystal-oriented film is preferred. Here, the crystal orientation by biaxial stretching means that the thermoplastic resin film before unstretched, that is, before the completion of crystal orientation is preferably stretched about 2.5 to 5 times in the longitudinal direction and the width direction, respectively. Thereafter, the crystal orientation is completed by heat treatment, and it indicates a biaxial orientation pattern by wide-angle X-ray diffraction.

  The thickness of the base film used in the present invention is appropriately selected according to the use for which the hard coat film of the present invention is used. From the viewpoint of mechanical strength and handling properties, it is preferably 10 to 500 μm, more Preferably it is 20-300 micrometers.

  The base film of the present invention may contain various additives, resin compositions, cross-linking agents and the like within a range that does not impair the effects of the present invention. For example, antioxidants, heat stabilizers, 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.

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

  Preferred examples of the ultraviolet absorber include salicylic acid compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, benzoxazinone compounds, and cyclic imino ester compounds, but at 380 nm to 390 nm. A benzoxazinone-based compound is most preferable from the viewpoints of ultraviolet cut-off 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 addition amount of these compounds is preferably 0.5 to 5% by weight in the base film.

  Moreover, 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). When used in combination with this, the aforementioned ultraviolet absorber is preferably 0.3 to 3% by weight in the base film.

  The hard coat film of the present invention preferably has a transmittance of 5% or less at a wavelength of 380 nm. This makes it possible to protect a substrate, a dye pigment and the like from ultraviolet rays, particularly when applied to a member for a plasma display.

  Further, the hard coat film of the present invention preferably has a total light transmittance of 80% or more because it has good transparency and is excellent in image visibility and sharpness when used as a display member.

  Further, the hard coat film of the present invention preferably has a transmission b value of 1.5 or less. If the transmission b value exceeds 1.5, the film itself appears slightly yellowish, which may impair the sharpness of the image.

  The total light transmittance was measured using the fully automatic direct reading haze computer HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.) to obtain the total light transmittance in the thickness direction of the hard coat film and set it as the average value of 10-point measurement.

  The light transmittance is a percentage of the ratio between the amount of incident light and the total amount of light that has passed through a test piece such as a film, and is a measure for measuring transparency as well as haze. Generally, when light enters the film plane from the air, first, partial reflection occurs on the surface. The light incident on the inside repeats losses such as absorption and scattering, causes back-surface reflection during emission, and exits to the opposite side. Accordingly, there are basically three factors that inhibit transparency: (i) reflection, (ii) absorption, and (iii) scattering.

  The transmission b value was measured by a transmission report according to JIS-K-7105 using a spectroscopic color difference meter SE-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

  The b value is a color specification method determined by the International Commission on Illumination (CIE). The b value represents saturation. If the b value is a positive sign, it is a yellow hue, and if it is a negative sign. Represents a blue hue. Further, the larger the absolute value, the larger the saturation of the color, and the brighter the color, and the smaller the absolute value, the smaller the saturation. When it is 0, it indicates an achromatic color. For example, colored pigments, organic pigments, dyes, and the like can be used as the pigments that can be realized by adding pigments, but because of excellent weather resistance, cadmium red, red rose, molybdenum red, Chrome Vermilion, Sankachrome, Viridian, Titanium Cobalt Green, Cobalt Green, Cobalt Chrome Green, Victoria Green, Ultramarine Blue, Bitumen Blue, Berlin Blue, Milori Blue, Cobalt Blue, Cerulean Blue, Cobalt Silica Blue, Cobalt Zinc Blue, Manganese Organic pigments such as violet, mineral violet, and cobalt violet are preferably used.

  In the hard coat film of the present invention, a hard coat layer is laminated on at least one side of the base film, and this hard coat layer is composed of a cured composition mainly composed of a polyfunctional acrylate and a melamine-based crosslinking agent. And a curable composition containing a silicone-based or fluorine-based additive.

  Here, a main component means that the hardening composition comprised from the polyfunctional acrylate and melamine type crosslinking agent which occupies for the whole hard-coat layer is 60 weight% or more, Preferably it is 70 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 per molecule, and 3 per molecule. More than one (meth) acryloyloxy group (in the present specification, "... (meth) acryl ..." means "... acrylic ... or ... metaacryl ...") As a monomer, oligomer, or prepolymer having 3), the hydroxyl group of a polyhydric alcohol having 3 or more alcoholic hydroxyl groups in one molecule is 3 or more (meth) acrylic. The compound etc. which are the esterified products of an acid can be mentioned.

  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-mentioned compounds, it is preferable to use one or two functional acrylates together for the purpose of relaxing the rigidity of the hard coat layer or reducing shrinkage during curing. 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, and the like.

  (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 and the like.

  (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 and the like.

(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.
Can be used.

  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 include polyester acrylates, urethane acrylates, epoxy acrylates and polyether acrylates, including those in which a reactive acrylic group is bonded to an acrylic resin skeleton, and rigid materials such as melamine and isocyanuric acid. A structure in which an acrylic group is bonded to a simple skeleton can also be used.

  Moreover, a reactive diluent can be used suitably. A reactive diluent is a coating agent component having a group that reacts with a monofunctional or polyfunctional acrylic oligomer as well as serving as a solvent in the coating process as a coating medium. 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. However, the present invention is not limited to these.

  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 Oil & 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, 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 weight with respect to 100 parts by weight 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 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, the coating agent for forming the hard coat layer needs to contain a melamine-based crosslinking agent. When the melamine-based crosslinking agent is not contained, the adhesiveness with the base film is insufficient, and the interference fringe reduction effect is also insufficient. The type of melamine-based 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 methylolated melamine with a lower alcohol, or these A mixture or the like 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 melamine-based crosslinking agent is not particularly limited, but the adhesiveness and hardness are 2 to 40% by weight, preferably 5 to 35% by weight, more preferably 10 to 30% by weight in the solid content of the hard coat forming coating. From the standpoint of balance without interference fringes. 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, styrenesulfonic acid, and derivatives thereof 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 the coating material for forming the hard coat layer used in the present invention, it is necessary to contain a silicone-based or fluorine-based additive. In the case where no silicone-based or fluorine-based additive is contained, the surface dirt wiping property is remarkably lowered. The type of the silicone-based or fluorine-based additive is not particularly limited, but as the silicone-based leveling agent, polydimethylsiloxane as a basic skeleton and a polyoxyalkylene group added (for example, SH190 manufactured by Toledo Corning Silicone Co., Ltd.) Although it is suitable, it is not limited to this. In addition, when a fluorine-based additive is used, a fluoroalkyl chain having a long chain (Kyoeisha Chemical Co., Ltd. FC-1000, 2000) is suitable, but is not limited thereto. The leveling agent is preferably added in an amount of 0.01 to 5% by weight in the hard coat layer forming composition.

  In the present invention, it is preferable not to interpose an adhesive layer between the base film and the hard coat layer. When the adhesive layer is interposed, interference fringes may be generated due to a difference in refractive index from the base film or the hard coat layer, or the adhesive layer may be deteriorated by ultraviolet rays or may have poor durability in high temperature and high humidity conditions.

  In the hard coat film of the present invention, the average waviness amplitude of reflectance at a wavelength of 400 to 600 nm measured from the hard coat layer side is 1% or less, preferably 0.8% or less, more preferably 0.6% or less. It is preferable that the interference fringes can be reduced.

  The average waviness amplitude of the reflectance at a wavelength of 400 to 600 nm described in the present invention means that measured by the following method. First, the hard coat surface of the hard coat film is used as a measurement surface, and the opposite surface is roughened with sandpaper or the like so that the 60 ° C. gloss (JIS Z 8741) is 10 or less. Next, the roughened portion is colored black so that the visible light average transmittance at a wavelength of 400 to 600 nm is 5% or less to obtain a measurement sample. FIG. 1 shows the results observed when the measurement surface is measured with a spectrophotometer at an incident angle of 10 degrees. In FIG. 1, curve (c) shows the relationship between the wavelength and the measured reflectance. In the reflectivity, undulation at a wavelength of 400 to 600 nm, that is, a maximal value (primary differential coefficient = 0, secondary differential coefficient <0) and a minimum in a calculus meaning of fluctuation of the reflectivity up and down as the wavelength changes. The difference between the values (primary differential coefficient = 0, secondary differential coefficient> 0) is defined as waviness amplitude (a). As shown in FIG. 1, a line (peak line (b)) connecting the peaks (maximum points) of the undulations of reflectance at wavelengths of 400 to 600 nm and a line (valley line) connecting the valley bottoms (minimum points) of the undulations. The difference between the two reflectance line graphs in (d)), that is, the undulation amplitude (a) including 11 sampling points (wavelength is (400 + 20 * i (i = i = 12)) including the boundary point (400, 600 nm). An integer of 0 to 10))) is obtained at a place where nm is obtained, and a value obtained by averaging these 11 values is defined as an average undulation amplitude.

  In order to achieve the above-described reduction of interference fringes and compatibility of transparency and antiglare properties, it is necessary that fine protrusions be formed at the interface between the base film and the hard coat layer. When the aspect ratio of the width and length of the protrusion is 1 to 10, more preferably 1 to 5, and the height is 0.05 to 1 μm, more preferably 0.1 to 1 μm, the transparency is lowered. The effect of reducing interference fringes is great, and the effect of improving antiglare properties is also great. In this way, by forming protrusions at the interface between the hard coat layer and the substrate and further defining the shape of the protrusions to be formed, it is possible to achieve both reduction of interference fringes and transparency and antiglare properties. It was.

The protrusion size was defined by the following method.
First, regarding the protrusion size, the hard coat surface was observed and photographed with an optical microscope (Leica DMLB HC manufactured by Leica Microsystems) (magnification 50 times). By lowering the condenser lens to the lowest point in the transmission mode and observing it, the interface protrusion of the hard coat / substrate can be observed. The width and length of the protrusions in a 1000 μm × 1000 μm square field of view were read from the image and the average value was measured. About the width | variety and length of a processus | protrusion, the length by the side of a short axis was prescribed | regulated as the width | variety in the photograph which image | photographed the interface of hard-coat / base material with said optical microscope. In the case of a perfect circle, the diameter was used. In the case of an ellipse, the minor axis was taken as the width of the protrusion.

  The long axis side was defined as the length. Moreover, about the height, the cross section of the hard coat film was observed and evaluated. Cross-sectional observation was performed by the following method. First, the cross-section of the hard coat film was cut in the film width direction at room temperature perpendicularly to the hard coat surface using a microtome (manufactured by Japan Microtome Laboratory). The cross section was observed with an optical microscope (magnification 1000 times), and an observation image was taken with an attached digital camera. The obtained image was magnified 5 times in the film thickness direction of the hard coat film by Photoshop (Adobe), the value read from the image was converted into the actual length, and the average height of the protrusions was calculated. The height was defined based on a flat surface (hard coat layer / substrate interface) having no protrusion, and the height from the flat portion was defined as the height of the protrusion. For the height, width, and length of the protrusions, all 20 points were measured and the average value was obtained.

  As a method for changing the size, for example, there are the following methods. The surface roughness of the embossing roll to which the concavo-convex structure is transferred can be changed variously, and the transferred shape after pressing can be changed. Further, although it can be changed by the pressing pressure and the pressing temperature at the time of transfer, the method described below is preferable.

  As a method for forming the protrusions, a case where a polyester film is used as the base film will be described. Said flat granular protrusion cannot be achieved by a method in which a hard coat layer is applied on a normal biaxially stretched polyester film and cured and laminated, and interference fringes are generated. As a method for forming protrusions suitable for the present invention, a hard coat coating agent is applied to a polyester film (crystallinity measured by Raman method from the film cross section is 3 to 25%) that is appropriately crystallized before crystal orientation is completed. A method obtained by coating the film, followed by stretching and heat treatment, and irradiating an active ray such as ultraviolet rays as necessary. In order to obtain an appropriately crystallized polyester film, the polyester film can be obtained by heating the melt-extruded unstretched film surface and stretching it in the longitudinal direction. The draw ratio is preferably about 2.5 to 3.2 times. It is also effective to add a crystallization nucleating agent to the film to promote crystallization or form microcrystals. Further, after coating, the film is stretched in the width direction through a preheating process. At this point, a solvent stress crack (solvent stress crack) occurs first, and after this, the hard coat coating agent penetrates and then the crack is blocked. The protrusion is formed by the difference in stretchability between the penetrating portion and the non-penetrating portion by stretching. The inventors have found that such a phenomenon is manifested by performing in-line coating. The film stretched in the width direction is continuously guided to a heat treatment step, and is heat treated at a high temperature of about 220 ° C. to 245 ° C., thereby hardening the hard coat layer and improving the adhesion to the base film. Let The heat treatment time is preferably longer, but is preferably about 10 to 40 seconds depending on the temperature. In addition, when the film is formed at a high speed and the amount of heat is insufficient, a method of curing by irradiating active rays such as ultraviolet rays after the heat treatment is effective.

  As a method for forming fine protrusions, in addition to the above, a mold is pressed on one side of a thermoplastic polyester film crystallized by biaxial stretching to form protrusions on the surface, and a hard coat composition is obtained in the obtained film shape It is effective to apply a material coating agent and perform heat treatment at a high temperature of 220 to 245 ° C. for about 10 to 40 seconds. As mold rolls used to form protrusions, those with fine irregularities and those with fine irregularities can be selected and applied as appropriate, and patterns, mats, lenticular lenses, and spherical irregularities are regularly or randomly arranged. it can. For example, although the convex part or recessed part which consists of a part of sphere whose height of a convex part or a recessed part is 0.01-10 micrometers is mentioned, it is not limited to this.

  Next, an example of the method for producing a hard coat film of the present invention will be described using polyethylene terephthalate (hereinafter abbreviated as PET) as an example of the base film, but is not limited thereto.

  A PET pellet (intrinsic viscosity 0.62 dl / g) containing 0.2% by weight of silica particles having an average particle diameter of 0.3 μm was vacuum-dried at 180 ° C. for about 2 hours to sufficiently remove moisture, and then an extruder. And melt extruded at a temperature of 260 to 300 ° C., and formed into a sheet form from a T-shaped die. The sheet-like material thus obtained is cooled and solidified on a mirror-like cooling drum to obtain an unstretched sheet. At this time, it is preferable to use an electrostatic application method for the purpose of improving the adhesion to the cast drum. Then, the obtained unstretched sheet is stretched 2 to 5 times in the longitudinal direction with a roll group heated to 70 to 120 ° C. Next, a hard coat layer-forming coating agent is applied to the surface of the film thus stretched uniaxially, and then guided to a tenter while holding both ends of the film with clips. After preheating to 70 to 110 ° C. in the tenter, the film is stretched about 2 to 5 times at 80 to 125 ° C. in the width direction. The laminated film stretched in the width direction is further subjected to a heat treatment for completing the crystal orientation and coating film curing of the base film while performing a relaxation treatment of 3 to 10% in an atmosphere at 220 to 245 ° C.

  The hard coat 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 generation of the iris pattern is 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, a substrate for windowing, a substrate for nameplates, 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.

  Although what is necessary is just to determine the thickness of a hard-coat layer according to a use, 0.1 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 0.1 μm, even if it is sufficiently cured, the surface hardness is not sufficient because it is too thin, and the surface tends to be damaged. 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.

  Moreover, you may provide printing layers, such as a pattern, in the outermost layer of a hard-coat layer in the range which does not impair the effect of this invention.

  Further, the obtained hard coat film 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 hard coat film of the present invention is bonded to a counterpart material using various adhesives on the opposite side of the hard coat layer, and the hard coat layer such as wear resistance and scratch resistance is attached to the counterpart material. It is also possible to use it with the above functions. The adhesive used at this time is not particularly limited as long as it is an adhesive that adheres two objects by its adhesive action, and an adhesive made of rubber, acrylic, silicone or polyvinyl ether is used. it can.

  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, and epoxy 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 lamination thickness is 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.

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

(1) Adhesion under normal conditions Under normal conditions (23 ° C., relative humidity 65%), 100 crosscuts of 1 mm ² are put on the hard coat layer of the hard coat film, and cellophane tape manufactured by Nichiban Co., Ltd. is pasted thereon. And then reciprocating three times with a load of 19.6 N using a rubber roller, and after pressing, peeled off in the direction of 90 degrees, and evaluated in four steps according to the number of remaining hard coat layers (◎: 100, ○: 80-99, Δ: 50-79, x: 0-49). (◎) and (○) were considered to have good adhesion.

(2) Antifouling property A 3 cm line is drawn on the top surface of the sample with a black pen (Penteru Pen ENN50 manufactured by Pentel Co., Ltd.), and the portion is wiped five times with a cellulosic non-woven fabric (Asahi Kasei Co., Ltd. Hyze gauze). This was done by visual judgment. Judgment criteria are shown below. ○ was accepted.

  ○: The first drawn line disappears and is almost invisible.

  X: The line drawn initially can be recognized clearly.

(3) Abrasion resistance The load on the hard coat layer surface was changed with steel wool # 0000, and rubbed 10 times (speed: 10 cm / s) under a constant load at each load, resulting in scratch resistance (not scratched). The maximum load that was present was measured. 2 kg / cm ² was a practically acceptable level and was accepted.

(4) Pencil hardness Measured according to JIS K-5400 using HEIDON (manufactured by Shinto Kagaku Co., Ltd.). 2H or higher was accepted.

(5) Average swell amplitude measurement The average swell amplitude was obtained from the reflectance curve at an incident angle of 10 degrees using a U-3410 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.).

  The reflectance at a wavelength of 400 to 600 nm was measured, and each wavelength (11 locations, 11 points, The difference (mountain line-valley line) at a wavelength of (400 + 20 * i (i = integer of 0 to 10)) nm was determined, and the average was taken as the average undulation amplitude.

(6) Measurement of the aspect ratio of the protrusion The aspect ratio of the protrusion was obtained by dividing the length of the protrusion calculated according to the following method by the width of the protrusion as the aspect ratio. The protrusions were photographed by observing the hard coat surface with an optical microscope (Leica DMLB HC manufactured by Leica Microsystems) (magnification 50 times). By lowering the condenser lens to the lowest point in the transmission mode and observing it, the interface protrusion of the hard coat / substrate can be observed. The width and length of the protrusions in a 1000 μm × 1000 μm square field of view were read from the image and the average value was measured. About the width | variety and length of a processus | protrusion, the length by the side of a short axis was prescribed | regulated as the width | variety in the photograph which image | photographed the interface of hard-coat / base material with said optical microscope. In the case of a perfect circle, the diameter was used. In the case of an ellipse, the minor axis was taken as the width of the protrusion. The long axis side was defined as the length. About the width | variety and length of protrusion, 20 points | pieces were measured and the average value was calculated | required.

(7) Measurement of height of protrusions The height was evaluated by observing the cross section of the hard coat film. Cross-sectional observation was performed by the following method. First, the cross-section of the hard coat film was cut in the film width direction at room temperature perpendicularly to the hard coat surface using a microtome (manufactured by Japan Microtome Laboratory). The cross section was observed with an optical microscope (magnification 1000 times), and an observation image was taken with an attached digital camera. The obtained image was magnified 5 times in the film thickness direction of the hard coat film by Photoshop (Adobe), and the value read from the image was converted into the actual length to obtain the average height of the protrusions. The height was defined based on a flat surface (hard coat layer / substrate interface) having no protrusion, and the height from the flat portion was defined as the height of the protrusion. About the height of the protrusion, 20 points were measured and the average value was obtained.

(8) Presence or absence of interference fringes After the surface of the measurement surface (hard coat layer surface side) is roughened with a 240th sandpaper in the same manner as when 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 was 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 A very weak iris pattern is visible: B rank A weak rainbow color pattern is visible: C rank A strong rainbow color pattern is clearly visible: D rank.

(9) Anti-glare Film in a dark room when the reflected fluorescent lamp is viewed while changing the viewpoint, placed 30 cm directly under the three-wave fluorescent lamp (National Parrook, three-wavelength daylight white (FL 15EX-N 15W)) The degree of reflection of the fluorescent lamp on the surface was visually evaluated. Judgment criteria are shown below. ○ The above was accepted.

The outline of the fluorescent light appears blurred: ◎
The outline of the fluorescent light appears slightly blurred: ○
The outline of the fluorescent light is clearly visible: ×.

(10) Total light transmittance Using a fully automatic direct reading haze computer HGM-2DP (manufactured by Suga Test Instruments Co., Ltd.), the total light transmittance in the thickness direction of the hard coat film was determined and used as the average value of 10-point measurement.

(11) Light resistance test Using an ultraviolet degradation 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.

(12) Transmission b value Using a spectroscopic color difference meter SE-2000 type (manufactured by Nippon Denshoku Industries Co., Ltd.), the transmission b value was measured by the transmission method according to JIS-K-7105.

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

<Coating agent A>
70 parts by weight of a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (KAYARAD-DPHA: manufactured by Nippon Kayaku Co., Ltd.), trimethylolpropane / ethylene oxide modified triacrylate (M-350: manufactured by Toagosei Co., Ltd.) ) 10 parts by weight, 20 parts by weight of fully alkylated melamine (Cymel C303: manufactured by Nippon Cytec Industries, Ltd.), 1 part by weight of a phosphoric acid catalyst (catalyst 296-9: manufactured by Nippon Cytec Industries, Inc.), silicone A mixed coating composition of 0.2 parts by weight of a leveling agent (SH190: manufactured by Toray Dow Corning Silicone Co., Ltd.) was prepared.

<Coating agent B>
The coating A was prepared in the same manner except that a fluorine leveling agent (manufactured by AFC-2000 Kyoeisha Chemical Co., Ltd.) was added instead of the silicone leveling agent.

<Coating agents C, D, E>
The coating A was prepared in the same manner except that the amount of the melamine crosslinking agent was 5 parts by weight (Coating C), 20 parts by weight (Coating D), and 35 parts by weight (Coating E).

<Coating agents F and G>
A coating agent was prepared in the same manner except that the type of the melamine crosslinking agent of coating agent A was changed as follows.

Coating F: Methylol-based melamine (Cymel C370: manufactured by Nippon Cytec Industries, Inc.)
Coating G: Methylol / imino group type melamine (Cymel C-701: manufactured by Nihon Cytec Industries Co., Ltd.)
<Coating agent H>
Coating material H was prepared in the same manner except that bifunctional acrylate (KAYARAD-HX-220) was used instead of DPHA of coating material A.

Example 1
A polyethylene terephthalate (extreme viscosity 0.63 dl / g) chip containing no filler was vacuum-dried at 180 ° C. for 3 hours, melted at 285 ° C. with an extruder, and then extruded into a sheet from a T-shaped die. After forming a non-stretched sheet on a cast drum at 0 ° C. using an electrostatic application cast method, this was preheated at 80 ° C. and stretched 3.5 times in the longitudinal direction by roll stretching at 90 ° C. Thereafter, the both ends were held with clips while being led to a 90 ° C. preheating zone, and subsequently stretched 3.3 times in the width direction in a 100 ° C. heating zone. Further, a heat treatment for 17 seconds was performed in a heat treatment zone at 230 ° C. while continuously performing a relaxation treatment in the width direction of 5% to obtain a polyester film having a thickness of 120 μm. On the surface of this film, a heat roll heated to 150 ° C. provided with a mold is formed by a roll having a mold (centerline average surface roughness Ra 0.5 μm) and a back roll, and a linear pressure of 100 N is provided. The fine structure was formed on the upper surface (on the side of the hot roll provided with the mold) by pressing at / cm and passing the film between both rolls. On this film, the coating agent A was applied with a microgravure, and then the film was fixed with a metal frame, heat-treated at 230 ° C. for 1 minute to cure the coating film, and a hard coat film was produced. The aspect ratio of the protrusions at the interface was 2, and the height was 0.2 μm. As shown in Table 1, the transmittance was as high as 90.9%, interference fringes were reduced, and antiglare properties were good. In addition, the adhesiveness, hardness and antifouling properties were good.

(Example 2)
A heat roll heated to 140 ° C. provided with a mold in a fine structure forming part composed of a roll (center line average surface roughness Ra 1.5 μm) and a back roll provided with a mold on the film surface used in Example 1. Was pressed at a linear pressure of 100 N / cm and passed between both rolls to form a fine structure on the upper surface (the hot roll side provided with the mold). On this film, the coating agent A was applied with a microgravure, and then the film was fixed with a metal frame, heat-treated at 230 ° C. for 1 minute to cure the coating film, and a hard coat film was produced. The aspect ratio of the protrusion on the interface was 1, and the height was 1 μm. As shown in Table 1, the transmittance was as high as 86.7%, interference fringes were reduced, and antiglare properties were good. In addition, the adhesiveness, hardness and antifouling properties were good.

(Example 3)
A heat roll heated to 150 ° C. provided with a mold in a fine structure forming part composed of a roll (center line average surface roughness Ra 0.1 μm) and a back roll provided with a mold on the film surface used in Example 1. Was pressed at a linear pressure of 150 N / cm and passed between both rolls to form a fine structure on the upper surface (the hot roll side provided with the mold). On this film, the coating agent A was applied with a microgravure, and then the film was fixed with a metal frame, heat-treated at 230 ° C. for 1 minute to cure the coating film, and a hard coat film was produced. The aspect ratio of the protrusions at the interface was 10, and the height was 0.05 μm. As shown in Table 1, the transmittance was as high as 89.0%, interference fringes were reduced, and antiglare properties were good. In addition, the adhesiveness, hardness and antifouling properties were good.

Example 4
A heat roll heated to 150 ° C. provided with a mold in a fine structure forming part composed of a roll (center line average surface roughness Ra 1.5 μm) and a back roll provided with a mold on the film surface used in Example 1. Was pressed at a linear pressure of 150 N / cm and passed between both rolls to form a fine structure on the upper surface (the hot roll side provided with the mold). On this film, the coating agent A was applied with a microgravure, and then the film was fixed with a metal frame, heat-treated at 230 ° C. for 1 minute to cure the coating film, and a hard coat film was produced. The aspect ratio of the protrusions at the interface was 1, and the height was 0.05 μm. As shown in Table 1, the transmittance was as high as 91.0%, interference fringes were reduced, and antiglare properties were good. In addition, the adhesiveness, hardness and antifouling properties were good.

(Example 5)
A heat roll heated to 150 ° C. provided with a mold in a fine structure forming part composed of a roll (centerline average surface roughness Ra 0.4 μm) and a back roll provided with a mold on the film surface used in Example 1. Was pressed at a linear pressure of 150 N / cm and passed between both rolls to form a fine structure on the upper surface (the hot roll side provided with the mold). On this film, the coating agent A was applied with a microgravure, and then the film was fixed with a metal frame, heat-treated at 230 ° C. for 1 minute to cure the coating film, and a hard coat film was produced. The aspect ratio of the protrusions at the interface was 10, and the height was 1.0 μm. As shown in Table 1, the transmittance was as high as 85.7%, interference fringes were reduced, and antiglare properties were good. In addition, the adhesiveness, hardness and antifouling properties were good.

(Example 6)
A polyethylene terephthalate (hereinafter referred to as PET intrinsic viscosity 0.63 dl / g) chip containing no filler is vacuum dried at 180 ° C. for 3 hours, then supplied to an extruder, melted at 285 ° C., and then sheeted from a T-shaped die. It was extruded into a shape, wound around a mirror cast drum having a surface temperature of 25 ° C. using an electrostatic application casting method, cooled and solidified to obtain an unstretched sheet. The unstretched sheet thus obtained was stretched 3.5 times in the longitudinal direction with a roll group heated to 95 ° C. to obtain a uniaxially stretched film. On one side of this uniaxially stretched film, the coating agent B described above was applied to a thickness of 20 μm by a die coating method. While holding both ends of the film coated with coating agent B with clips, the film was guided to a preheating zone at 90 ° C., and subsequently stretched 3.3 times in the width direction in a heating zone at 100 ° C. Further, a heat treatment for 17 seconds was performed in a heat treatment zone at 230 ° C. while continuously performing a relaxation treatment in the width direction of 5%, and the coating film was cured and heat-set. The hard coat film thus obtained was excellent in transparency with a layer thickness of 125 μm and a hard coat layer thickness of 5 μm. The aspect ratio of the protrusions at the interface was 2, and the height was 0.2 μm. As shown in Table 1, the transmittance was as high as 90.9%, interference fringes were reduced, and antiglare properties were good. Also, the adhesiveness, hardness and antifouling properties were good.

(Comparative Example 1)
In Example 1, a mold having a center line average surface roughness of 2.0 μm was used instead of Ra 0.5 μm, and the temperature of the heat roll provided with the mold was 160 ° C. instead of 150 ° C. Similarly, a hard coat film was produced. The aspect ratio of the protrusions at the interface was 15, and the height was 1 μm. As shown in Table 1, the transmittance was as low as 78.0%, and the transparency was poor. Further, the interference fringes were reduced and the antiglare property was good. Further, the adhesiveness, hardness and antifouling property were good.

(Comparative Example 2)
In Example 1, except that the mold centerline average surface roughness was 0.05 μm instead of Ra 0.5 μm, and the temperature of the hot roll provided with the mold was 130 ° C. instead of 150 ° C. Similarly, a hard coat film was produced. The aspect ratio of the protrusions at the interface was 3, and the height was 0.03 μm. As shown in Table 1, the transmittance was as high as 89.0% and the transparency was excellent, but the interference fringes were poor. Further, the antiglare property was also poor. Adhesiveness, hardness and antifouling properties were good.

(Comparative Example 3)
In Example 1, a mold having a center line average surface roughness of 1.5 μm was used instead of Ra 0.5 μm, and the temperature of the hot roll provided with the mold was 100 ° C. instead of 150 ° C. Similarly, a hard coat film was produced. The aspect ratio of the protrusions at the interface was 12, and the height was 0.02 μm. As shown in Table 1, the transmittance was as high as 90.3% and the transparency was good, but the interference fringes were poor. Further, the antiglare property was also poor. Adhesion, hardness and antifouling properties were all good.

(Comparative Example 4)
A polyethylene terephthalate (hereinafter referred to as PET intrinsic viscosity 0.63 dl / g) chip containing no filler is vacuum dried at 180 ° C. for 3 hours, then supplied to an extruder, melted at 285 ° C., and then sheeted from a T-shaped die. It was extruded into a shape, wound around a mirror cast drum having a surface temperature of 25 ° C. using an electrostatic application casting method, cooled and solidified to obtain an unstretched sheet. The unstretched sheet thus obtained was stretched 3.0 times in the longitudinal direction with a roll group heated to 95 ° C. to obtain a uniaxially stretched film. On one side of the uniaxially stretched film, the above-mentioned coating agent A was applied to a thickness of 20 μm by a die coating method. The film coated with coating agent A was guided to a preheating zone at 90 ° C. while holding both ends of the film with clips, and then stretched 3.5 times in the width direction in a heating zone at 100 ° C. Further, the coating film was cured and heat-fixed by heat treatment for 17 seconds in a heat treatment zone at 100 ° C. while continuously performing a relaxation treatment in the width direction of 5%. The hard coat film thus obtained had a layer thickness of 125 μm and a hard coat layer thickness of 5 μm. The aspect ratio of the protrusion on the interface was 21, and the height was 0.6 μm. As shown in Table 1, the transmittance was as low as 79.0%, and the transparency was poor. The interference fringes were reduced and the antiglare property was good. Further, the adhesiveness, hardness and antifouling property were good.

(Examples 7 to 9)
In Example 1, the same procedure as in Example 1 was used except that the coating agent C (Example 7), the coating agent D (Example 8), and the coating agent E (Example 9) were used instead of the coating agent A. Thus, a hard coat film was prepared. As shown in Table 1, good adhesion and hardness were exhibited regardless of the amount of melamine crosslinking agent added. Further, the interference fringes were reduced and the visibility and transparency were excellent.

(Examples 10 and 11)
A hard coat film was prepared in the same manner as in Example 1, except that the coating A was changed to the coating F (Example 10) and the coating G (Example 11). As shown in Table 1, the adhesion and hardness were good even when the melamine species were changed. Further, the interference fringes were reduced and the visibility and transparency were excellent.

(Comparative Example 5)
A laminated film was prepared in the same manner as in Example 1 except that the coating A was changed to the coating H.
As shown in Table 1, the aspect ratio of the protrusions at the interface was 5, and the height was 1.1 μm. Further, the interference fringes were reduced and the transparency, adhesiveness, antifouling property and antiglare property were good, but both the wear resistance and hardness were poor.

(Examples 12 to 13)
A master chip was prepared by compounding the PET used in Example 1 with a biaxial vent extruder so that the addition amount of the following UV absorber was 12% by weight.

Ultraviolet absorber A: 2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazin-4-one) → PET master A
Ultraviolet absorber B: 1,3 bis (2′cyano-3,3-diphenylacryloyloxy) -2,2-bis- (2′cyano-3,3-diphenylacryloyloxymethylpropane) → PET master B
Ultraviolet absorber C: 2,2′-methylene-bis- [6- (2H-benzotriazol-2-yl) -4- (methyl) phenol] → PET master C
The master chip and the PET chip of Example 1 were vacuum-dried at 180 ° C. for 3 hours and then blended, and PET raw material A (using PET master A. Example 12), PET raw material B (using PET master B. Example 13) ), PET raw material C (using PET master C. Example 13) was prepared. The density | concentration of the ultraviolet absorber in PET raw material AC was 1.5 weight% with respect to the total amount of PET. This raw material was melt extruded at 285 ° C., and a hard coat layer was provided in the same manner as in Example 1 to prepare a hard coat film. As shown in Table 2, it was a hard coat film excellent in adhesiveness, surface hardness and interference fringe reduction of the hard coat layer and having a small transmission b value after ultraviolet irradiation.

(Comparative Example 6)
On a PET film having a thickness of 100 μm, 12.5 parts by weight of an ultraviolet curable acrylic resin (Aronix UV-3700: Toa Gosei Chemical Co., Ltd.), acrylic resin particles (average particle size 5 μm, Techpolymer MB30X-SS: Sekisui Plastics Co., Ltd.) Company) Ionizing radiation effect paint consisting of 0.1 parts by weight, 12.0 parts by weight of methyl ethyl ketone and 16.7 parts by weight of toluene was applied with a Mayer bar, and irradiated with UV light for 1 to 2 seconds with a high pressure mercury lamp. A hard coat layer having a binder part thickness of 4 μm was provided to obtain a hard coat film. As shown in Table 2, although it was excellent in the adhesion, surface hardness, interference fringe reduction, and antiglare property of the hard coat layer, it was a hard coat film inferior in antifouling property.

  The film of the present invention provides a highly transparent hard coat film that is excellent in adhesion to the hard coat layer without substantially intervening the adhesive layer, further has small interference fringes, and is also excellent in light resistance. Yes, it can be used in various applications such as LCD and PDP displays, touch panels, window coverings, and nameplates.

It is the wavelength / reflectance graph which showed the waviness amplitude of the reflectance.

Claims (7)

In the hard coat film in which the hard coat layer is laminated on at least one side of the base film,
Fine protrusions are formed on the hard coat layer side surface of the base film,
The aspect ratio of the width and length of the protrusion is 1 to 10,
A hard coat film having protrusions having a height of 0.05 to 1 μm. The hard coat film according to claim 1, wherein the hard coat layer comprises a composition containing a polyfunctional acrylate and a melamine-based crosslinking agent as main components and a silicone-based or fluorine-based additive. The hard coat film according to claim 1 or 2, wherein the average waviness amplitude of the reflectance on the hard coat layer side at a wavelength of 400 to 600 nm is 1% or less. The hard coat film according to claim 1, wherein no adhesive layer is interposed between the base film and the hard coat layer. The hard coat film according to claim 1, wherein the base film contains an ultraviolet absorber. The hard coat film according to claim 1, wherein the total light transmittance is 80% or more, the transmission b value is 1.5 or less, and the transmittance at 380 nm is 5% or less. The hard coat coating agent is applied to at least one surface of the base film to provide a hard coat layer, and then produced by an in-line coating method including a step of stretching and curing in at least one direction. The hard coat film as described.

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