JP2012027401A - Hard coat film and antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coat film and an antireflection film that can prevent a blocking at the time of manufacture and a devitrification of the product surface due to polyester oligomers, and can suppress an increase of haze adequately.SOLUTION: In a hard coat film 1a according to the present invention, a first hard coat layer 3 which is a cured coating film of (meth)acrylic resin is provided on a front surface of a polyester film 2 and a second hard coat layer 4 which is a cured coating film of (meth)acrylic resin including silica particles of average particle diameter of 100 to 350nm in an amount of 5 to 80 mass% and having a thickness of equal to or more than the average particle diameter of the silica particle and 5000nm or less is provided on a back surface of the polyester film 2.

Description

  The present invention relates to a hard coat film and an antireflection film. More specifically, the present invention relates to a hard coat film and an antireflection film used for, for example, an optical display device.

  Conventionally, optical display devices such as cathode ray tube display (CRT), plasma display panel (PDP), liquid crystal display (LCD), projection display, electroluminescence display (ELD), touch panel, optical lens, spectacle lens, photolithography Optical film such as polyester film used for antireflection treatment in the process, antireflection treatment of solar cell panel surface, etc. is generally applied to the surface to prevent scratches due to heavy scratches and improve the mechanical strength of the surface. A hard coat layer is provided.

  As an optical film provided with such a hard coat layer, a hard coat film having a hard coat layer on the surface of the base film (see Patent Documents 1 and 2), a hard coat layer on the surface of the base film, and a low refractive index An antireflection film (see Patent Documents 3 and 4) provided with an index layer in this order to provide antireflection properties is used.

  The hard coat layer of these hard coat films and antireflection films is formed by applying and curing a reactive curable resin composition of (meth) acrylic resin mainly on the surface of the base film.

  These hard coat films and antireflection films may be provided with a hard coat layer as described above on the back surface in addition to the front surface, depending on the application.

  The manufacturing process of such a hard coat film and an antireflection film is generally performed by a so-called roll-to-roll method, and in each process, the film is unwound and wound by a roll.

  However, in such a roll-to-roll manufacturing process, the front and back surfaces of the hard coat film and the antireflection film come into contact with each other during winding. When the front and back surfaces come into contact with each other in this way, blocking may occur, causing a problem in winding. In particular, blocking is likely to occur when a hard coat layer made of the same quality material is provided on the front and back surfaces.

  Further, when a polyester film is used as the substrate, when the front and back surfaces of the hard coat film and the antireflection film are in contact with each other as described above, the product surface may become cloudy due to the oligomer contained in the polyester film.

  Conventionally, various technologies for preventing blocking of a hard coat film and an antireflection film and white turbidity of a product surface due to an oligomer contained in a polyester film have been studied. For example, a method for providing a slipperiness by providing a coating film containing a filler (filler) on the back surface of a hard coat film, etc., a method for interposing a sandwiched film or a protective film when winding with a roll such as a hard coat film, A method using a release agent such as silicone oil has been studied.

JP 2008-129130 A JP 2000-52472 A JP 2009-31769 A JP 2004-258267 A

  However, the method of providing a slipperiness by providing a coating film containing a filler on the back surface of a hard coat film or the like has a problem that haze increases due to light scattering on the surface of the filler. In addition, when a filler having a particle diameter that does not scatter light is used, the slipperiness is not expressed.

  In addition, the method of interposing the sandwiched film or the protective film during winding with a roll such as a hard coat film has a problem that the manufacturing cost increases.

  And in the method using a mold release agent, there existed a problem that a mold release agent transcribe | transfers to product surfaces, such as a hard coat film.

  The present invention has been made in view of the circumstances as described above, can prevent blocking at the time of production, can prevent the product surface from being clouded by the polyester oligomer, and further sufficiently suppress the increase in haze. An object of the present invention is to provide a hard coat film and an antireflection film that can be used.

  In the hard coat film of the present invention, a first hard coat layer that is a cured coating film of a (meth) acrylic resin is provided on the surface of a polyester film, and silica having an average particle diameter of 100 to 350 nm is provided on the back surface of the polyester film. A second hard coat layer which is a cured coating film of a (meth) acrylic resin having a particle content of 5 to 80% by mass and a thickness of not less than the average particle diameter of the silica particles and not more than 5000 nm is provided. .

  In the antireflection film of the present invention, the first hard coat layer which is a cured coating film of (meth) acrylic resin and the low refractive index layer having a refractive index of 1.30 to 1.50 are arranged in this order on the surface of the polyester film. A cured coating film of a (meth) acrylic resin having 5 to 80% by mass of silica particles having an average particle size of 100 to 350 nm and a thickness of not less than 5000 nm and not more than 5000 nm on the back surface of the polyester film. A second hard coat layer is provided.

  According to the present invention, it is possible to prevent blocking at the time of production, to prevent white turbidity of the product surface due to the polyester oligomer, and to sufficiently suppress an increase in haze.

(A) is sectional drawing which shows an example of the hard coat film of this invention, (b) is sectional drawing which shows an example of the antireflection film of this invention.

  Hereinafter, the present invention will be described in detail.

  Fig.1 (a) is sectional drawing which shows an example of the hard coat film of this invention.

  This hard coat film 1a has a polyester film 2 as a base material. A first hard coat layer 3 is provided on the surface of the polyester film 2, and a second hard coat layer 4 is provided on the back surface of the polyester film 2.

  The first hard coat layer 3 and the second hard coat layer 4 are composed of a (meth) acrylic resin as a resin material, and the second hard coat layer 4 contains silica particles in the (meth) acrylic resin. ing.

  That is, the second hard coat layer 4 contains 5 to 80% by mass of silica particles having an average particle diameter of 100 to 350 nm, and the thickness is set to be not less than the average particle diameter of the silica particles and not more than 5000 nm.

  At least a part of the silica particles contained in the second hard coat layer 4 is aggregated to form secondary particles having a particle diameter of, for example, about 200 to 700 nm. Some silica particles including such secondary particles protrude from the surface of the second hard coat layer 4.

  Thereby, when it winds up by the roll in the manufacturing process of the hard coat film 1a, the contact of the front and back surfaces of the hard coat film 1a is suppressed by the silica particles protruding from the surface of the second hard coat layer 4. Therefore, blocking of the front and back surfaces of the hard coat film 1a can be prevented.

  Further, by providing the second hard coat layer 4 as described above on the back surface of the polyester film 2, it is possible to prevent the product surface from being clouded by the polyester oligomer contained in the polyester film 2.

  Furthermore, by using silica particles having the above-mentioned specific average particle diameter, light scattering by the silica particles can be suppressed, and an increase in haze can be sufficiently suppressed. For example, compared with the case where silica particles are not blended, an increase in haze can be suppressed to 0.3% or less, for example.

  FIG.1 (b) is sectional drawing which shows an example of the antireflection film of this invention.

  This antireflection film 1b has a polyester film 2 as a base material. A first hard coat layer 3 and a low refractive index layer 5 are provided in this order on the surface of the polyester film 2, and a second hard coat layer 4 is provided on the back surface of the polyester film 2.

  The first hard coat layer 3 and the second hard coat layer 4 are constituted by using a (meth) acrylic resin as a resin material, and the second hard coat layer 4 is formed of the above-mentioned hard coat film on a (meth) acrylic resin. Silica particles having the same average particle diameter as 1a are contained in the same amount.

  By setting it as such a structure, like the said hard coat film 1a, when winding up to the roll in the manufacturing process of the antireflection film 1b, the contact of the front and back surfaces of the antireflection film 1b is the second hard coat. Suppressed by silica particles protruding from the surface of the layer 4. Therefore, blocking of the front and back surfaces of the antireflection film 1b can be prevented.

  Further, by providing the second hard coat layer 4 as described above on the back surface of the polyester film 2, it is possible to prevent the product surface from being clouded by the polyester oligomer contained in the polyester film 2.

  Furthermore, by using silica particles having the above-mentioned specific average particle diameter, light scattering by the silica particles can be suppressed, and an increase in haze can be sufficiently suppressed. For example, compared with the case where silica particles are not blended, an increase in haze can be suppressed to 0.3% or less, for example.

  Hereinafter, the hard coat film 1a of the present invention will be described.

  In this invention, as polyester which forms the polyester film 2, the aromatic polyester obtained from aromatic dicarboxylic acid and glycol can be used, for example.

  As the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid and the like can be used.

  As the glycol, for example, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol and the like can be used.

  Among aromatic polyesters, polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate are particularly preferable. Moreover, the copolymer polyester of the component illustrated above may be sufficient.

  The polyester film 2 is necessary to improve the film winding property during film formation, the film transportability when forming the first hard coat layer 3 and the second hard coat layer 4, and the like. Thus, inorganic or organic fine particles as a lubricant can be contained.

  Examples of such fine particles include inorganic fine particles such as calcium carbonate, calcium oxide, aluminum oxide, kaolin, silicon oxide, and zinc oxide, or crosslinked acrylic resin fine particles, crosslinked polystyrene resin fine particles, urea resin fine particles, melamine resin fine particles, and crosslinked particles. Organic fine particles such as silicone resin fine particles can be used.

  Further, the polyester film 2 is provided with other components such as a colorant, an antistatic agent, an ultraviolet absorber, an antioxidant, a lubricant, a catalyst, and other resins within a range that does not impair the transparency. It can be included.

  Although the thickness of the polyester film 2 is not specifically limited, For example, it is 50-200 micrometers.

  The polyester film 2 has a haze of preferably 3% or less, more preferably 1.5% or less. If the haze exceeds 3%, problems such as impaired visibility of the display may occur.

  In the present invention, the first hard coat layer 3 is a film having a hardness higher than that of the polyester film 2, which improves the hardness of the surface of the polyester film 2, prevents scratches caused by scratching with a load, and hard coat film It improves the mechanical strength of 1a.

  The pencil hardness of the first hard coat layer 3 is preferably H or higher, more preferably 2H or higher.

  The first hard coat layer 3 can be formed using a reactive curable resin composition of a (meth) acrylic resin, for example, an ionizing radiation curable resin composition.

  In this specification, (meth) acrylic resin means acrylic resin or methacrylic resin.

  As the resin component to be blended in the ionizing radiation curable resin composition of (meth) acrylic resin, a compound having an acrylate functional group is preferably used. Examples of the compound having an acrylate functional group include, for example, relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and polyvalent resins. Polyfunctional (meth) acrylate oligomers such as alcohol resins, prepolymers, and the like can be used. In the present specification, (meth) acrylate means acrylate or methacrylate.

  Moreover, the monomer as a reactive diluent can be mix | blended with said ionizing radiation curable resin composition with said oligomer and prepolymer. Examples of such monomers include monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone, trimethylolpropane tri (meth) acrylate, hexanediol ( (Meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neo Polyfunctional monomers such as pentyl glycol di (meth) acrylate can be used.

  Further, when the ionizing radiation curable resin composition is an ultraviolet curable resin composition, it is preferable to add a photopolymerization initiator. As the photopolymerization initiator, for example, acetophenones, benzophenones, α-amyloxime esters, thioxanthones and the like can be used.

  Moreover, you may use a photosensitizer with a photoinitiator. As the photosensitizer, for example, n-butylamine, triethylamine, tri-n-butylphosphine, thioxanthone, or the like can be used.

  When forming the first hard coat layer 3 using an ultraviolet curable resin composition that undergoes a photopolymerization reaction, for example, the ultraviolet curable resin composition is applied on the polyester film 2 and dried, and then irradiated with ultraviolet rays. Can be cured.

  The first hard coat layer 3 can contain other components as long as the effects of the present invention are not impaired. Examples of such other components include high refractive index particles such as particles of at least one oxide selected from zinc, titanium, aluminum, cerium, yttrium, lanthanum, zirconium, tin, indium, antimony, and niobium. , Dyes, antistatic agents and the like.

  The thickness of the first hard coat layer 3 is, for example, 0.3 to 10 μm from the viewpoint of obtaining sufficient mechanical strength.

  The refractive index of the first hard coat layer 3 is, for example, 1.50 to 1.65 in consideration of optical characteristics required for an optical display device or the like.

  In the present invention, the second hard coat layer 4 is, for example, a reactive curable resin composition of a (meth) acrylic resin as exemplified above in the first hard coat layer 3, such as an ionizing radiation curable resin. Using the composition, it can be formed by blending silica particles therein.

  The silica particles blended in the second hard coat layer 4 are preferably spherical silica in consideration of suppression of light scattering by the silica particles and expression of easy slipping.

  The average particle diameter of the silica particles is 100 to 350 nm. The average particle diameter can be measured by a dynamic light scattering method. If the average particle diameter of the silica particles is too small, the anti-blocking property may be lowered, and if the average particle diameter of the silica particles is too large, the haze of the coating film may be increased.

  The content of the silica particles in the second hard coat layer 4 is 5 to 80% by mass with respect to the total amount of the second hard coat layer 4. If the content of the silica particles is too small, it may be difficult to prevent blocking, and if the content of the silica particles is too large, problems such as an increase in haze and impaired production suitability may occur.

  The thickness of the second hard coat layer 4 is not less than the average particle diameter of the silica particles and not more than 5000 nm. When the thickness of the second hard coat layer 4 is less than the average particle diameter of the silica particles, the wear resistance may be lowered, and when the thickness of the second hard coat layer 4 is too large, the anti-blocking property is lowered. There is a case.

  The pencil hardness of the second hard coat layer 4 is preferably H or higher, more preferably 2H or higher.

  As described above, according to the hard coat film 1a of the present invention, the silica particles having the specific average particle diameter (primary particles) are added to the second hard coat layer 4 on the back surface of the polyester film 2 as described above. By containing in an amount, a part of the silica particles, at least a part of which is aggregated to form secondary particles, protrudes from the surface of the second hard coat layer 4. Thereby, when it winds up by the roll in the manufacturing process of the hard coat film 1a, the contact of the front and back surfaces of the hard coat film 1a is suppressed by the silica particles protruding from the surface of the second hard coat layer 4. Therefore, blocking of the front and back surfaces of the hard coat film 1a can be prevented.

  Further, by providing the second hard coat layer 4 as described above on the back surface of the polyester film 2, it is possible to prevent the product surface from being clouded by the polyester oligomer contained in the polyester film 2.

  Furthermore, by using silica particles having the above-mentioned specific average particle diameter, light scattering by the silica particles can be suppressed, and an increase in haze can be sufficiently suppressed.

  Next, the antireflection film 1b of the present invention will be described.

  In the antireflection film 1b of the present invention, the polyester film 2, the first hard coat layer 3, and the second hard coat layer 4 are configured as exemplified in the first hard coat film 1a. it can.

  The low refractive index layer 5 is a layer having a refractive index smaller than that of the polyester film 2 and the first hard coat layer 3, and a low refractive index coating agent is applied to the surface of the first hard coat layer 3. Can be formed.

  The surface of the first hard coat layer 3 is preferably subjected to a surface treatment before the low refractive index layer 5 is formed. Examples of such surface treatment include physical surface treatment such as plasma discharge treatment, corona treatment and flame treatment, and chemical surface treatment with a coupling agent, acid, alkali and the like. By performing such surface treatment, the wettability and adhesion between the first hard coat layer 3 and the low refractive index layer 5 can be improved.

  The low refractive index layer 5 has a refractive index of 1.30 to 1.50 from the viewpoint of reducing the reflectance by the combination with the first hard coat layer 3. The thickness d of the low refractive index layer 5 is preferably nd = λ / 4, where n is the refractive index of the low refractive index layer 5 and λ is the wavelength of incident light. Specifically, the thickness of the low refractive index layer 5 is preferably 50 to 400 nm, and more preferably 50 to 200 nm.

  The low refractive index coating agent contains a binder material and can be prepared by itself when the binder material itself has a low refractive index, but it can also be prepared by blending low refractive index particles in the binder material. it can.

  As the binder material, for example, a hydrolyzate of silicon alkoxide, or a polymer (ultraviolet curable resin, thermosetting resin) having a saturated hydrocarbon or polyether as a main chain can be used. Moreover, what has a structural unit containing a fluorine atom in these molecules can also be used.

As the silicon alkoxide of the binder material, for example, a compound represented by R _m Si (OR ′) _n can be used. Here, R and R ′ represent an alkyl group having 1 to 10 carbon atoms, m and n each represents an integer, and m + n is 4.

  Examples of such compounds include tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, and tetra-tert-butoxy. Silane, tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxy Silane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethyl Ropokishishiran, dimethyl-butoxy silane, methyl dimethoxy silane, can be used methyl diethoxy silane, hexyl trimethoxy silane. In addition, oligomers and polymers having these as basic skeletons, or copolymers of at least two of them can also be used.

  The binder material can be prepared, for example, by dissolving the above silicon alkoxide in a suitable solvent and hydrolyzing it.

  Examples of the solvent include alcohols such as isopropyl alcohol, methanol, and ethanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and butyl acetate, aromatic hydrocarbons such as toluene and xylene, and halogenated carbons. Hydrogen can be used. These may be used alone or in combination of two or more.

The silicon alkoxide is dissolved in the above solvent so that the silicon alkoxide is 100% hydrolyzed and condensed and is preferably 0.1% by mass or more, more preferably 0.1 to 10% by mass in terms of SiO ₂ generated. To do. When the silicon alkoxide concentration is too low, the formed sol film may not exhibit the desired characteristics sufficiently. On the other hand, when the silicon alkoxide concentration is too high, it becomes difficult to form a transparent and homogeneous film. There is.

To this solution, more water than necessary for hydrolysis is added, preferably at a temperature of 15 to 35 ° C., more preferably 22 to 28 ° C., preferably 0.5 to 10 hours, more preferably 2 to 5 hours. Stir. A catalyst is preferably used for the hydrolysis, and as the catalyst, for example, an acid such as hydrochloric acid, nitric acid, sulfuric acid, acetic acid or the like can be used. These acids are preferably added as an aqueous solution of 0.001 to 20.0 N, more preferably 0.005 to 5.0 N, and water in the aqueous solution can be used as water for hydrolysis. The SiO ₂ sol thus obtained is a colorless and transparent liquid, is a stable solution having a pot life of about 1 month, has good wettability with respect to the substrate, and is excellent in coating suitability.

  A reactive organosilicon compound or a partial hydrolyzate thereof may be added to the hydrolyzate of silicon alkoxide. As such a reactive organosilicon compound, a plurality of groups that react and crosslink by heat or ionizing radiation, for example, an organosilicon compound having a molecular weight of 5000 or less having a polymerizable double bond group can be used.

  Specifically, for example, one terminal vinyl functional polysilane, both terminal vinyl functional polysilane, one terminal vinyl functional polysiloxane, both terminal vinyl functional polysiloxane, or a vinyl functional polysilane obtained by reacting these compounds, Vinyl functional polysiloxanes and the like can be used.

  The polymer having a saturated hydrocarbon or polyether as the main chain as the binder material is preferably crosslinked.

  The polymer having a saturated hydrocarbon as the main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. Moreover, in order to obtain the polymer of the binder material bridge | crosslinked, it is preferable to use the monomer which has two or more ethylenically unsaturated groups.

  As monomers having two or more ethylenically unsaturated groups, for example, ethylene glycol di (meth) acrylate, 1,4-dichlorohexanediacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylol Propane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetra Esters of polyhydric alcohols such as methacrylate, polyurethane polyacrylate, polyester polyacrylate and (meth) acrylic acid; 1,4-divinylbenzene, 4-vinyl Benzoic acid-2-acryloyl ethyl ester, 1,4-divinylbenzene and derivatives thereof divinyl cyclohexanone; divinyl sulfone vinyl sulfone; methylenebisacrylamide acrylamide can be used, such as methacrylamide.

  Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the polymer of the binder material by the reaction of a crosslinkable functional group. Examples of such crosslinkable functional groups include isocyanate groups, epoxy groups, aziridine groups, oxazoline groups, aldehyde groups, carbonyl groups, hydrazine groups, carboxyl groups, methylol groups, and active methylene groups. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester, and urethane can also be used as a monomer for introducing a crosslinked structure. In addition, you may use the functional group which shows crosslinkability as a result of a decomposition reaction like a block isocyanate group.

  As the polymer having a polyether as a main chain, for example, a polymer synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound can be used.

  As the polymerization initiator used for the polymerization reaction and crosslinking reaction of the polymer of the binder material, for example, a photopolymerization initiator can be used. Examples of the photopolymerization initiator include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds , Fluoroamine compounds and aromatic sulfoniums can be used. In addition, a thermal polymerization initiator can also be used.

  The low refractive index particles blended in the binder material preferably have a refractive index of 1.20 to 1.45.

  The average particle size of the low refractive index particles is preferably 0.5 to 200 nm. When the average particle diameter is larger than 200 nm, light is irregularly reflected by Rayleigh scattering in the obtained low refractive index layer 5, and the low refractive index layer 5 looks whitish and its haze value may increase. If the thickness is less than 0.5 nm, the dispersibility of the low refractive index particles decreases, and aggregation occurs in the liquid of the low refractive index coating agent.

  The amount of the low refractive index particles added is preferably 20 to 99% by volume with respect to the total amount of the low refractive index layer 5 in consideration of lowering the refractive index, surface hardness, wear resistance, and the like.

  As the low refractive index particles, for example, hollow particles such as silica fine particles and hollow silica fine particles, or fluoride fine particles such as magnesium fluoride, lithium fluoride, aluminum fluoride, calcium fluoride, and sodium fluoride can be used. it can. These may be used alone or in combination of two or more. These low refractive index particles can be subjected to a surface treatment for imparting compatibility with a resin or the like of the binder material.

  The hollow particles are fine particles having a cavity surrounded by an outer shell. As a hollow particle, the hollow particle currently disclosed by Unexamined-Japanese-Patent No. 2001-233611 can be used, for example.

The material constituting the outer shell of the hollow particles, for _{example, SiO 2, SiO x, TiO} 2, TiO x, SnO 2, CeO 2, Sb 2 O 5, ITO, ATO, Al ₂ O _3, or the like alone, Or the thing of the form of the mixture of any combination of these materials can be used. Further, a composite oxide of any combination of these materials may be used. Note that SiO _x is preferably SiO ₂ when fired in an oxidizing atmosphere.

  Low refractive index coating agents include, for example, dip coating, spin coating, spray coating, roll coating, gravure roll coating, reverse coating, transfer roll coating, micro gravure coating, cast coating, calendar coating It can be coated on the first hard coat layer 3 subjected to the surface treatment by a liquid phase method such as a method or a die coating method. After coating, the solvent in the coating film is volatilized by heating and drying, and then the coating film is cured by heating, humidification, ultraviolet irradiation, electron beam irradiation, etc., and the low refractive index layer 5 can be formed.

  As described above, according to the antireflection film 1 b of the present invention, the antireflection layer is formed by providing the first hard coat layer 3 and the low refractive index layer 5 in this order on the surface of the polyester film 2. Prevention performance is imparted. And the silica particle which has said specific average particle diameter (primary particle) in said 2nd hard-coat layer 4 of the back surface of the polyester film 2 by said specific quantity aggregates at least one part. Part of the silica particles forming the secondary particles protrudes from the surface of the second hard coat layer 4. Thereby, when it winds up by the roll in the manufacturing process of the antireflection film 1b, the contact of the front and back surfaces of the antireflection film 1b is suppressed by the silica particles protruding from the surface of the second hard coat layer 4. Therefore, blocking of the front and back surfaces of the antireflection film 1b can be prevented.

  Further, by providing the second hard coat layer 4 as described above on the back surface of the polyester film 2, it is possible to prevent the product surface from being clouded by the polyester oligomer contained in the polyester film 2.

  Furthermore, by using silica particles having the above-mentioned specific average particle diameter, light scattering by the silica particles can be suppressed, and an increase in haze can be sufficiently suppressed.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.
<Example 1>
As the polyester film, a polyethylene terephthalate (PET) film (“A4300” manufactured by Toyobo Co., Ltd., PET film thickness 100 μm) was used.

  As the ultraviolet curable resin composition for forming the first hard coat layer, an acrylic ultraviolet curable resin (“HC301” manufactured by Dainichi Seika Kogyo Co., Ltd., solid content 60%) was used.

  The ultraviolet curable resin composition for forming the first hard coat layer was applied to the surface of the polyester film with a wire bar coater # 10.

This was dried at 80 ° C. for 5 minutes and then cured by UV irradiation (500 mJ / cm ² ) to form a first hard coat layer having a thickness of 5.0 μm.

  As an ultraviolet curable resin composition for forming the second hard coat layer, an acrylic ultraviolet curable resin (“DIC608” manufactured by DIC, 60% solid content) and silica particles (“IPA-ST manufactured by Nissan Chemical Industries, Ltd.”) are used. -L ", an average particle diameter of 100 nm) dispersed by 15% by mass (in terms of solid content) was used.

  The ultraviolet curable resin composition for forming the second hard coat layer was applied to the back surface of the polyester film with a wire bar coater # 6.

This was dried at 80 ° C. for 3 minutes and then cured by UV irradiation (500 mJ / cm ² ) to form a second hard coat layer having a thickness of 1.0 μm, thereby obtaining a hard coat film.
<Example 2>
In Example 1, the ultraviolet curable resin composition for forming the second hard coat layer was prepared by adding silica particles (“MEK-ST2040” manufactured by Nissan Chemical Industries, Ltd., average particle) to the acrylic ultraviolet curable resin of Example 1. The diameter was changed to 10% by mass (solid content conversion) dispersed. Otherwise, a hard coat film was obtained in the same manner as in Example 1.
<Example 3>
In Example 1, the compounding amount of the silica particles was changed to 30% by mass (solid content conversion) with respect to the total amount of the ultraviolet curable resin composition for forming the second hard coat layer. Otherwise, a hard coat film was obtained in the same manner as in Example 1.
<Example 4>
As the polyester film, a polyethylene terephthalate (PET) film (“A4300” manufactured by Toyobo Co., Ltd., PET film thickness 100 μm) was used.

  As the ultraviolet curable resin composition for forming the first hard coat layer, an acrylic ultraviolet curable resin (“HC301” manufactured by Dainichi Seika Kogyo Co., Ltd., solid content 60%) was used.

  The ultraviolet curable resin composition for forming the first hard coat layer was applied to the surface of the polyester film with a wire bar coater # 10.

This was dried at 80 ° C. for 5 minutes and then cured by UV irradiation (500 mJ / cm ² ) to form a first hard coat layer.

  As an ultraviolet curable resin composition for forming the second hard coat layer, an acrylic ultraviolet curable resin (“DIC608” manufactured by DIC Corporation, solid content 60%) and silica particles (“MEK-” manufactured by Nissan Chemical Industries, Ltd.) are used. ST2040 ”, an average particle size of 250 nm) dispersed in 10% by mass (in terms of solid content) was used.

  The ultraviolet curable resin composition for forming the second hard coat layer was applied to the back surface of the polyester film with a wire bar coater # 6.

This was dried at 80 ° C. for 3 minutes and then cured by UV irradiation (500 mJ / cm ² ) to form a second hard coat layer having a thickness of 1.0 μm, thereby obtaining a hard coat film.

  Next, a low refractive index coating agent was applied to the surface of the first hard coat layer to form a low refractive index layer. The low refractive index coating agent is obtained by adding 356 parts by mass of methanol to 208 parts by mass of tetraethoxysilane, adding 18 parts by mass of water and 18 parts by mass of 0.01N hydrochloric acid aqueous solution, and mixing them with a disper to obtain a mixed solution. After that, this mixed solution was stirred in a constant temperature bath at 40 ° C. for 1 hour, and a silicone resin whose weight average molecular weight was adjusted to 850 was used as a binder material.

  Next, as a low refractive index particle, “CS60-IPA” (solid content: 20%) manufactured by Catalytic Chemical Industry Co., Ltd. is blended into the silicone resin in an amount that is 50% by volume of the total amount of the silicone resin matrix. The low refractive index coating agent was prepared by diluting with methanol so that the solid content was 3% by mass.

A low refractive index coating agent is applied to the surface of the first hard coat layer with a wire bar coater # 4 so as to have a thickness of 100 nm, and then dried at 100 ° C. for 2 minutes to form a low refractive index layer. A film was obtained.
<Comparative Example 1>
In Example 1, the ultraviolet curable resin composition for forming the second hard coat layer was prepared by adding silica particles (“IPA-ST” manufactured by Nissan Chemical Industries, Ltd., average particle) to the acrylic ultraviolet curable resin of Example 1. The diameter was changed to 15% by mass (solid content conversion) dispersed. Otherwise, a hard coat film was obtained in the same manner as in Example 1.
<Comparative example 2>
In Example 1, the ultraviolet curable resin composition for forming the second hard coat layer was prepared by adding silica particles (“SIRMIBK15WT% -E68”, average particle, manufactured by CIK Nanotech Co., Ltd.) to the acrylic ultraviolet curable resin of Example 1. The diameter was changed to 10% by mass (in terms of solid content) dispersed. Otherwise, a hard coat film was obtained in the same manner as in Example 1.
<Comparative Example 3>
In Example 1, the ultraviolet curable resin composition for forming the second hard coat layer was prepared by adding silica particles (“MEK-ST2040” manufactured by Nissan Chemical Industries, Ltd., average particle) to the acrylic ultraviolet curable resin of Example 1. The diameter was changed to 10% by mass (solid content conversion) dispersed. Then, the ultraviolet curable resin composition for forming the second hard coat layer was applied with a wire bar coater # 4. This was dried at 80 ° C. for 3 minutes and then cured by UV irradiation (500 mJ / cm ² ) to form a second hard coat layer having a thickness of 0.15 μm. Otherwise, a hard coat film was obtained in the same manner as in Example 1.
[Haze]
It measured using the haze meter (Nippon Denshoku Industries Co., Ltd. "NDH2000").
[Pencil hardness]
Using pencils having different hardnesses, the pencil hardness was measured according to JIS K5600 under a load of 750 g.
[Blocking resistance]
The films of Examples and Comparative Examples were wound on a roll, the films were overlapped, and the blocking resistance was evaluated according to the following criteria under the condition of being left at 40 ° C. for 24 hours under a load of 1 kg / cm ² .
○: No adhesion between specimens ×: Between specimens
[Opaque film surface (Δhaze)]
After winding the film of an Example and a comparative example on a roll, the cloudiness of the film surface considered to originate in the polyester oligomer contained in the polyester film of a base material was evaluated by the haze change by heating. Specifically, the change in haze after heating for 60 minutes at 100 ° C. (haze increase: Δhaze) was measured and evaluated according to the following criteria.
○: Δhaze 0.1% or more ×: Δhaze less than 0.1% Table 1 shows the evaluation results.

  From Table 1, the 2nd hard coat layer containing a silica particle is provided in the back surface of a polyester film, the average particle diameter of a silica particle shall be 100-350 nm, content shall be 5-80 mass%, and the 2nd hard coat In Examples 1 to 4 in which the thickness of the layer was within the range of the average particle diameter of the silica particles to 5000 nm or less, it had slipperiness, small haze, blocking resistance, and no cloudiness on the film surface. .

  On the other hand, in Comparative Examples 1 to 3, in which the average particle diameter of the silica particles in the second hard coat layer or the thickness of the second hard coat layer is outside the above range, any of blocking resistance, haze, and pencil hardness is used. Was not satisfied.

DESCRIPTION OF SYMBOLS 1a Hard coat film 1b Antireflection film 2 Polyester film 3 First hard coat layer 4 Second hard coat layer 5 Low refractive index layer

Claims (2)

  A first hard coat layer, which is a cured coating of (meth) acrylic resin, is provided on the surface of the polyester film, and 5 to 80% by mass of silica particles having an average particle diameter of 100 to 350 nm is provided on the back surface of the polyester film. And a second hard coat film which is a cured coating film of a (meth) acrylic resin having a thickness of not less than the average particle diameter of the silica particles and not more than 5000 nm.   A first hard coat layer that is a cured coating of (meth) acrylic resin and a low refractive index layer having a refractive index of 1.30 to 1.50 are provided in this order on the surface of the polyester film, and on the back surface of the polyester film. The second hard coat layer is a cured coating film of a (meth) acrylic resin containing 5 to 80% by mass of silica particles having an average particle diameter of 100 to 350 nm and a thickness of not less than the average particle diameter of the silica particles and not more than 5000 nm An antireflection film characterized by being provided.

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