TWI389798B - An anti-reflectance film - Google Patents

Description

Antireflection film

The present invention relates to an antireflection film, and more particularly, to effectively preventing light reflection on a surface of a picture display element such as a plasma display (PDP), a cathode ray tube (CRT), or a liquid crystal display (LCD) while suppressing dust. The antireflection layer which is excellent in the durability and scratch resistance of the adhesion-resistant antistatic effect and excellent in solvent resistance is a one-layer type antireflection film.

In a display such as a PDP, a CRT, or an LCD, light is emitted from the outside to the screen, and light is reflected and the display screen is not visible. In particular, in recent years, as the size of the display has increased, it has become increasingly important to solve the above problems.

In order to solve such problems, various anti-reflection treatments or anti-glare treatments are currently performed for various displays. One of them is the use of anti-reflective films on various displays.

Conventionally, this antireflection film is produced by a method of thinning a low refractive index substance (MgF ₂ ) on a substrate film by a dry process such as vapor deposition or sputtering, or a substance having a high refractive index [ITO (tin) A method in which a colloidal indium oxide, TiO ₂ or the like and a low refractive index substance (MgF ₂ , SiO _{2 ,} etc.) are alternately laminated. However, the antireflection film produced by the dry process has a high manufacturing cost.

In recent years, the wet process has been studied to produce an antireflection film by coating. However, the antireflection film produced by the wet process method has poor surface friction resistance as compared with the above antireflection film produced by the dry process.

In order to solve the above problems in the wet process, it is disclosed that a hardened layer (hard coat layer) is formed using an ionizing radiation curable resin composition. For example, on the base film, (1) sequentially stacking (A) a hard coating layer having a thickness of 2 to 20 μm of a hardened resin formed by ionizing radiation, and (B) containing at least two kinds of radiation by ionizing radiation. The hardening resin and the metal oxide of the tin oxide doped tin oxide, the high refractive index layer having a refractive index of 1.65 to 1.80 and having a thickness of 60 to 160 nm, and (C) the germanium-containing polymer having a refractive index of 1.37 ~1.47 A low refractive index layer having a thickness of 80 to 180 nm, and a formed optical film (for example, refer to Patent Document 1), (2) sequentially laminating (A) a metal oxide-containing film and formed by heat or ionizing radiation. a hard coating having a thickness of 2 to 20 μm and (B) a porous cerium oxide and a polyoxyalkylene polymer having a refractive index of 1.30 to 1.45 and a thickness of 40 to 200 nm. The optical film formed by the rate layer (for example, refer to Patent Document 2).

These optical films are antireflection films which are excellent in abrasion resistance while preventing light reflection on the surface of the screen display element.

On the other hand, the antireflection film is antistatic property which is excellent in durability in order to prevent adhesion of dust or the like. In order to provide the optical film having excellent antistatic properties, for example, in the optical film of (1), a metal oxide having an antistatic property is used as the metal oxide of the (B) high refractive index layer, or (2) In the optical film, an antistatic metal oxide is used as the metal oxide of the (A) high refractive index layer.

However, in the one-layer type in which only the low-refractive-index layer is laminated on the hard coating layer, an anti-reflection film having antistatic properties other than the use of the siloxane compound in the low-refractive-index layer has not been developed until now.

(Patent Document 1) JP-A-2002-341103 (Patent Document 2) JP-A-2003-139908

In view of the above, an object of the present invention is to provide an effect of effectively preventing light reflection on the surface of a screen display element such as a PDP, a CRT, or an LCD, and suppressing the durability of the antistatic effect such as adhesion of dust and the like, and excellent scratch resistance, and solvent resistance. The excellent antireflection layer is also an antireflection film of one layer type.

The present inventors have made efforts to develop an antireflection film having excellent properties as described above, and have found that a hard coating layer containing a hardening resin irradiated with an active energy ray and a quantitative antistatic agent is sequentially laminated on a substrate film. The present invention has been achieved by the low refractive index layer containing a hardening resin irradiated with an active energy ray and a quantitative porous cerium oxide particle, and the present invention has been completed based on this finding.

That is, the present invention provides (1) at least on one side of the base film, sequentially having (A) a hardening resin containing an active energy ray, and 2 to 25% by weight of an antistatic agent having a thickness of 1 to 20 μm. a hard coating layer, and (B) a hardening resin coated with an active energy ray, and a low refractive index layer having a thickness of 0.05 to 0.3 μm of 30 to 80% by weight of porous cerium oxide particles, and a surface resistivity of 5 the antireflection film × 10 ¹² Ω / □ or less of the antireflection film (2) of the above (1), wherein the antistatic agent-based molecule (a) at least one layer containing a cationic group of the quaternary ammonium salt-based An antistatic agent, and (3) an antireflection film according to the above (1) or (2), wherein the porous cerium oxide particles of the (B) layer have a specific gravity of 1.7 to 1.9, a refractive index of 1.25 to 1.36, and an average value. A substance having a particle diameter of 20 to 100 nm.

[Best form of implementing the invention]

The antireflection film of the present invention has a structure in which (A) a hard coating layer and (B) a low refractive index layer are sequentially laminated on at least one side of a base film according to a wet method.

In the antireflection film of the present invention, the substrate film is not particularly limited, and may be suitably selected from a plastic film of a substrate previously used as an antireflection film. Such plastic films, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and other polyester films, polyethylene film, polypropylene film, cellophane, two Acetyl cellulose film, triethylene glycol film, acetonitrile cellulose butyrate film, polyvinyl chloride film, polyvinyl chloride film, polyvinyl alcohol film, ethylene-vinyl acetate film, polystyrene Film, polycarbonate film, polymethylpentene film, polyfluorene film, polyetheretherketone film, polyether fluorene film, polyether quinone film, polyimide film, fluororesin film, polyamide film An acrylic resin film, a decene-based film, a cycloolefin resin film, or the like.

These substrate films may be transparent, translucent, colored or uncolored, and are appropriately selected depending on the use. For example, when the use is for the protection of a liquid crystal display, a colorless and transparent film is preferable.

The thickness of such a base film is not particularly limited and may be appropriately selected, and is generally 15 to 250 μm, preferably 30 to 200 μm. Moreover, in order to improve the adhesiveness of the base film and the layer provided on the surface, it is possible to perform surface treatment by an oxidation method, a roughening method, etc. on one surface or both surfaces as needed. The oxidation method is, for example, a corona discharge treatment, a chromic acid treatment (wet type), a flame treatment, a hot air treatment, an ozone-ultraviolet irradiation treatment, or the like, and a roughening method such as a sand blast method or a solvent treatment method. These surface treatment methods are appropriately selected depending on the type of the base film, and generally, the effect and workability are considered, and the corona discharge treatment method is preferable. Further, it is also possible to use an initiator device on one or both sides.

In the antireflection film of the present invention, at least one side of the base film is provided with (A) a hard coating layer containing a hardening resin and an antistatic agent which are irradiated with an active energy ray.

The hard coating layer containing a hardening resin and an antistatic agent which are irradiated with an active energy ray is formed by coating a hard coating layer containing, for example, an active energy ray curable compound, the above antistatic agent, and a desired photopolymerization initiator. The liquid is formed by coating a coating film on at least one side of the base film, and irradiating the active energy ray to cure the coating film.

The active energy ray-curable compound refers to a compound containing energy in an electromagnetic wave or a charged particle beam, that is, a compound which is crosslinked and hardened by irradiation of ultraviolet rays or electron beams.

Such active energy ray curable compounds such as photopolymerizable prepolymers and/or photopolymerizable monomers. The photopolymerizable prepolymer has a radical polymerization type and a cationic polymerization type, and a radical polymerization type photopolymerizable prepolymer such as a polyester acrylate type, an epoxy acrylate type, a urethane acrylate type, or a polyalcohol acrylic acid. Ester system, etc. The method for producing a polyester acrylate-based prepolymer, for example, by esterifying a hydroxyl group of a polyester low polymer having a hydroxyl group at both terminals by condensation of a polyvalent carboxylic acid and a polyvalent alcohol with (meth)acrylic acid It can be obtained by esterifying an epoxide with (meth)acrylic acid to esterify a hydroxyl group at the lower polymer end of the polyvalent carboxylic acid.

The method for producing a cyclochloroacrylate prepolymer is, for example, obtained by esterifying a (meth)acrylic acid in an oxirane ring of a low molecular weight bisphenol epoxy resin or a novolak epoxy resin. . The method for producing a urethane acrylate-based prepolymer is obtained, for example, by esterifying a polyamic acid low polymer obtained by a reaction of a polyether polyol or a polyester polyol with a polyisocyanate with (meth)acrylic acid. Further, the method for producing a polyalcohol acrylate prepolymer is obtained by esterifying a hydroxyl group of a polyether polyol with (meth)acrylic acid. One type of these photopolymerizable prepolymers may be used alone or in combination of two or more.

On the other hand, an epoxy resin is generally used as the cationically polymerizable photopolymerizable prepolymer. In the epoxy resin, for example, a compound in which a polyvalent phenol such as a bisphenol resin or a novolac resin is epoxidized with epichlorohydrin or the like, and a linear olefin compound or a cyclic olefin compound is oxidized by a peroxide or the like. And the obtained compound and the like.

Photopolymerizable monomers such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene-2 Alcohol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxytrimethylacetic acid neopentyl glycol di(meth)acrylate, dicyclopentyl di(methyl) Acrylate, caprolactone denatured dicyclopentyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate, deuterated cyclohexyl di(meth)acrylate, isomeric cyanide Acid ester di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid denatured dipentaerythritol tri(meth)acrylate, pentaerythritol tris(a) Acrylate, propylene oxide denatured trimethylolpropane tri(meth)acrylate, tris(propyleneoxyethyl)isocyanate, propionic acid denatured dipentaerythritol penta (meth) acrylate, A polyfunctional acrylate such as dipentaerythritol hexa(meth)acrylate or caprolactone denatured dipentaerythritol hexa(meth)acrylate. One type or two or more types of these photopolymerizable monomers may be used in combination, or may be used in combination with the photopolymerizable prepolymer.

The photopolymerization initiator to be used as desired, for the radically polymerizable photopolymerizable prepolymer or the photopolymerizable monomer, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, Benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylamine phthalate, 2,2-dimethoxy-2-phenylethyl benzene, 2,2-diethoxy-2 -Phenylethyl benzene, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl benzophenone, 2-methyl-1-[4-(methylthio)benzene 2-morpholine-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbiphenyl Ketone, 4,4'-diethylamine benzophenone, dichlorobenzophenone, 2-methyl hydrazine, 2-ethyl hydrazine, 2-tert-butyl fluorene, 2-amino hydrazine 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-di Ethyl thioxanthone, benzyl dimethyl ketone acetal, acetophenone acetal, p-dimethylamine benzoate, etc. . Further, in the cationic polymerization type photopolymerizable prepolymer, the photopolymerization initiator is, for example, an aromatic sulfonium ion, an aromatic oxysulfurium ion, an aromatic iodide ion or the like, a tetrafluoroborate, or a hexafluoride. A compound composed of an anion such as fluorophosphate, hexafluorodecyl ester or hexafluoroarsenazo. One type or two or more types may be used in combination, and the amount thereof is usually in the range of 0.2 to 10 parts by weight based on 100 parts by weight of the photopolymerizable prepolymer and/or the photopolymerizable monomer.

On the other hand, the antistatic agent contained in the hard coating layer is not particularly limited, and at least one selected from the conventionally known nonionic, anionic, cationic or amphoteric antistatic agents can be used. Among them, a cationic antistatic agent containing one or more quaternary ammonium bases in the molecule is preferable in view of the effects and the homogeneous dispersibility of the hard coating layer.

A cationic antistatic agent containing a quaternary ammonium base can be used in any of a low molecular type and a high molecular type, but it is considered to have a continuous effect of the effect and a preventive property of the exhaust gas or the generated gas. Electrostatic agents are ideal.

The polymer type cationic antistatic agent may be appropriately selected from any of the conventionally known antistatic agents. Specifically, for example, intramolecular inclusion

(wherein R ¹ and R ² each represent the same or different alkyl group having 1 to 10 carbon atoms; and R ³ represents an alkyl group having 1 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms; ^{n -} is an anion of n valence, and n is an integer of 1 to 4.)

The polymer of the quaternary ammonium base represented by the above is preferred.

In the above formula (I), the alkyl group represented by R ¹ and R ^{2 and} the alkyl group in R ³ , for example, an alkyl group having 1 to 6 carbon atoms, particularly preferably an alkyl group having 1 to 4 carbon atoms, and further preferably R ³ is an aralkyl group with benzyl ideal. The alkyl group having 1 to 4 carbon atoms is, for example, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a second butyl group or a t-butyl group.

On the other hand, X ^{n -} is any inorganic anion or organic anion such as halogen ions such as F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , ClO ₄ ^- , BF ₄ ^- , CO ₃ ^{2 -} , SO _^42-- inorganic ^{_{anion, CH 3 OSO 3 -, C}} 2 H 5 OSO 3 -, and acetic acid, malonic acid, succinic acid, maleic acid, fumaric acid, p-toluenesulfonic acid, trifluoroacetic acid and other organic acids The residue consists of an organic anion.

Such a polymer type quaternary ammonium salt-based antistatic agent is, for example, a compound of the following formula, that is, a polyvinylbenzyl type [(a)], a poly(meth)acrylate type [(b)], a styrene-( Methyl) acrylate copolymer type [(c)], styrene-maleic anhydride imide copolymer type [(d)], methacrylate-methacrylimide copolymer type [(e) ]Wait. Further, the copolymer type of (c), (d) and (e) may be any of a random copolymer type and a block copolymer type.

(only, R is expressed as H or CH ₃ )

(only, R is expressed as H or CH ₃ )

(However, in the above (a) to (e), x, y, and z are expressed as the degree of polymerization (3 to 30))

In the present invention, one type or two or more types of the polymer type cationic antistatic agent may be used in combination.

On the other hand, a low molecular type cationic antistatic agent, for example, contains the formula (II)

(In the formula, A is represented by an alkyl group having 10 to 30 carbon atoms, R ⁴ and R ⁵ are each an alkyl group having the same or different carbon number of 10, and R ⁶ is an alkyl group having 1 to 10 carbon atoms or a carbon number. 7 to 10 aralkyl groups, Y ^{m -} system m-valent anions, m systems 1 to 4 integers.)

The compound represented by the quaternary ammonium base is preferred.

A in the above formula (II), for example, a tetradecyl group such as lauryl group, a tetradecyl group such as a myristyl group, a hexadecyl group such as a palmity group, an octadecyl group such as a stearyl group, an octadecyl group or a Twelve carbon bases, etc.

Further, R ⁴ , R ⁵ , R ⁶ , Y ^{m -} and m are the same as R ¹ , R ² , R ³ , X ^{n -} and n in the formula (I), respectively.

In the present invention, one type or two or more types of the low molecular type cationic antistatic agent may be used in combination.

Further, the antistatic agent in the present invention may be a reactive cationic antistatic agent containing one or more quaternary ammonium bases and one or more polymerizable unsaturated groups in the molecule.

By using such a reactive cationic antistatic agent, when the active energy ray is irradiated, it is copolymerized with the above-mentioned active energy ray-curable compound, and the anti-reflective film is improved by the penetration into the formed polymer chain. Performance continuity.

The reactive cationic antistatic agent, for example, formula (III)

(wherein R is represented by a hydrogen atom or a methyl group.)

A reactive quaternary ammonium salt compound or the like is shown.

In the present invention, one type or two or more types of the reactive cationic antistatic agents may be used in combination. Further, the polymer type cationic antistatic agent, the low molecular type cationic antistatic agent, and the reactive cationic antistatic agent may be appropriately combined.

In the present invention, the content of the antistatic agent in the (A) layer, that is, the hard coating layer is in the range of 2 to 25% by weight. If the content of the antistatic agent is in the above range, the antireflection film exhibits good antistatic properties without adversely affecting other properties. The desirable content is 3 to 25% by weight, and more preferably in the range of 5 to 20% by weight.

In the coating liquid for forming a hard coating layer of the present invention, the active energy ray-curable compound, the antistatic agent, the photopolymerizable initiator which is used as desired, and various additives may be respectively required in a predetermined ratio. For example, an antioxidant, an ultraviolet absorber, a photostabilizer, a leveling agent, an antifoaming agent, etc. are added, dissolved, or dispersed in a suitable solvent to prepare.

The solvent used at this time is, for example, an aliphatic hydrocarbon such as hexane, heptane or cyclohexane, an aromatic hydrocarbon such as toluene or xylene, a halogenated hydrocarbon such as methyl chloride or ethane chloride, methanol, ethanol, propanol or butanol. And alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, methyl isobutyl ketone and isophorone; esters such as ethyl acetate and butyl acetate; Solvents such as a class of ethyl cellosolve are solvents.

The concentration and viscosity of the coating liquid thus prepared are not particularly limited, and the concentration and viscosity of the coating may be applied. It can be appropriately selected depending on the situation.

Next, the coating liquid is coated on the substrate by a conventionally known method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. A coating film is formed on at least one side of the film, and after drying, the coating film is cured by irradiation with active energy rays to form a hard coating layer.

Active energy rays such as ultraviolet rays or electron rays. The above ultraviolet rays may be derived from a high pressure mercury lamp, a weld fusion H lamp, a xenon lamp, or the like. On the other hand, electron rays can be obtained by using an electron beam accelerator. Among the active energy rays, ultraviolet rays are particularly desirable. Further, when an electron beam is used, a cured film can be obtained without adding a polymerization initiator.

In the present invention, the thickness of the (A) hard coating layer is in the range of 1 to 20 μm. If the thickness of the antireflection film is less than 1 μm, the anti-reflection film cannot sufficiently exhibit the rubbing resistance, and if it exceeds 20 μm, the hard coating layer is liable to crack. The ideal thickness of the hard coating layer is in the range of 2 to 15 μm.

In the optical film of the present invention, the refractive index of the (A) hard coating layer is generally from 1.45 to 1.60, more preferably from 1.49 to 1.55.

In the antireflection film of the present invention, (B) a low refractive index layer containing a hardening resin irradiated with active energy rays and porous ceria particles is provided on the hard coating layer.

The method for forming a low refractive index layer containing a hardening resin irradiated with active energy rays and porous ceria particles, which contains, for example, an active energy ray hardening compound, the above porous cerium oxide particles, and a desired photopolymerization initiation A coating liquid for forming a low refractive index layer such as a coating agent is applied to the (A) hard coating layer to form a coating film, which is formed by curing the coating film by irradiation with active energy rays.

The active energy ray-curable compound and the photopolymerization initiator used as desired are as described in the above description of the (A) hard coating layer.

The porous cerium oxide particles contained in the layer (B) may suitably have a specific gravity of 1.7 to 1.9, a refractive index of 1.25 to 1.36, and an average particle diameter of 20 to 100 nm. By using porous cerium oxide particles having such traits, a one-layer type antireflection film excellent in antireflection properties can be obtained.

In the present invention, the content of the porous cerium oxide particles in the layer (B) is in the range of 30 to 80% by weight. When the content of the porous cerium oxide particles is within the above range, the layer (B) can be a layer having a desired low refractive index, and the obtained antireflection film is excellent in antireflection property. The desirable content of the porous cerium oxide particles is preferably from 50 to 80% by weight, and particularly preferably from 60 to 75% by weight.

The thickness of the (B) layer is 0.05 to 0.3 μm, and the refractive index is generally in the range of 1.30 to 1.42. When the thickness and refractive index of the (B) layer are within the above range, an antireflection film excellent in antireflection performance, antistatic property, and abrasion resistance can be obtained. The ideal thickness of the (B) layer is 0.07 to 0.13 μm, and the ideal refractive index is in the range of 1.35 to 1.40.

In the coating liquid for forming a low refractive index layer of the present invention, the active energy ray-curable compound, the porous cerium oxide particles, and the above-mentioned photopolymerizable initiator which are used as desired can be respectively required in a predetermined ratio. Further, various additives such as an antioxidant, an ultraviolet absorber, a photostabilizer, a leveling agent, an antifoaming agent, and the like are added, dissolved, or dispersed in a suitable solvent to prepare.

The solvent used at this time is as described in the above description of the coating liquid for forming a hard coating layer.

The concentration and viscosity of the coating liquid thus prepared are not particularly limited, and the concentration and viscosity of the coating may be applied. It can be appropriately selected depending on the situation.

The above coating liquid is coated on (A) hard by a conventionally known method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. A coating film is formed on the coating layer, and after drying, the coating film is cured by irradiation with active energy rays to form a (B) low refractive index layer.

The active energy ray is as described in the description of the hard coating layer described above.

In the present invention, it is advantageous to carry out the formation of the (A) hard coating layer and the (B) low refractive index layer by the following method.

First, a coating liquid for forming a hard coating layer is applied to one surface of a base film to form a film, and the active energy ray is irradiated to be cured to a semi-cured state. At this time, when ultraviolet rays are irradiated, the amount of light is generally about 50 to 150 mJ/cm ² . Then, the coating liquid for forming a low refractive index layer is applied onto the formed hardened layer in a semi-cured state to form a coating film, and the active energy ray is sufficiently irradiated to be completely cured simultaneously with the hardened layer in the semi-cured state. At this time, when ultraviolet rays are irradiated, the amount of light is generally about 200 to 1000 mJ/cm ² .

In this manner, the (A) hard coating layer and the (B) low refractive index layer having excellent adhesion between the (A) layer and the (B) layer are sequentially formed on the base film.

The antireflection film of the present invention thus produced has a surface resistivity of 5 × 10 ^{1 2} Ω / □ or less. When the surface resistivity is 5 × 10 ^{1 2} Ω/□ or less, the antistatic property is exhibited, and the antireflection film is less likely to adhere to dust or the like. The lower limit of the surface resistivity is not particularly limited, but is generally 1 × 10 ⁸ Ω/□. Further, the antireflection film of the present invention has an average reflectance of visible light of 3% or less.

In addition, since (B) a low refractive index layer containing a curing resin which is irradiated with active energy rays is provided on the (A) hard coating layer, it has excellent antistatic property and solvent resistance, and can suppress the solvent. The phenomenon of low antistatic performance.

Further, the measurement of the surface resistivity will be described later.

In this way, it is possible to obtain an anti-reflection layer which is effective in preventing light reflection on the surface of various image display elements, has an excellent antistatic effect for suppressing adhesion of dust, and is excellent in abrasion resistance, and is excellent in solvent resistance. Reflective film.

In the antireflection film of the present invention, when a hard coating layer is provided on one surface of the base film, the hard coating layer can be formed on the opposite side surface to be adhered to an adhesive layer of a adherend such as a liquid crystal display. The adhesive constituting the adhesive layer is preferably an optical coating material such as an acrylic adhesive, a urethane adhesive, or an anthraquinone adhesive. The thickness of the adhesive layer is generally 5 to 100 μm, preferably 10 to 60 μm.

Further, a delaminated film may be disposed on the adhesive layer. The delamination film is a material which is coated with a separating agent such as enamel resin, for example, on paper such as cellophane, coated paper, laminated paper, and various plastic films. The thickness of the layer from the film is not particularly limited and is generally 20 to 150 μm.

[Examples]

Next, the present invention will be described in more detail by way of examples, but the invention is not limited thereto.

Further, the physical properties of the antireflection film obtained in each of the examples were measured by the following methods.

(1) Reflectance at wavelengths of 500 nm, 600 nm, and 700 nm Reflectance at wavelengths of 500 nm, 600 nm, and 700 nm was measured by a spectrophotometer ("UV-3101PC" manufactured by Shimadzu Corporation).

(2) Surface resistivity A parallel electrode connected to a digital electronic measuring instrument manufactured by Advantest Co., Ltd. was used for measurement according to JIS K 6911. Further, the surface resistivity after wiping off the ethanol was measured by the following method.

The surface of the low refractive index layer was wiped back and forth five times with a gauze soaked with ethanol, and then wiped back and forth five times with dry gauze, and then left to stand in an environment of 23° C. and a relative humidity of 50% for 30 minutes, and then the surface was similarly applied. Determination of resistivity.

(3) abrasion resistance using # 0000 steel wool, in weight 9.8 × 10 ^{- 3} N / mm ² after 5 double rubs times, was visually observed to determine the following criteria for evaluation.

○: no scratches ×: scratches

Example 1

(1) Preparation of liquid A (coating liquid for forming a hard coating layer): Diluted with pentaerythritol triacrylate of 45 parts by weight of a trifunctional acrylate monomer by 1-methoxy-2-propanol (East Asia Synthetic Co., Ltd.) , product name "ARONIX M-305", solid concentration: 100%), 0.9 parts by weight of 2-methyl-1-[4-(methylthio)phenyl]-2-morpholine used as a photopolymerization initiator -propan-1-one (trade name (IRGACURE 907), manufactured by Ciba Specialty Chemicals Co., Ltd., solid content concentration: 100%), and 90 parts by weight of a polymeric cationic antistatic agent containing a quaternary ammonium base (manufactured by Colcoat Co., Ltd.) A mixture of the product name "Colcoat NR-121X-9IPA" and a solid content of 9.5 wt%) was prepared to prepare a liquid A (coating liquid for forming a hard coating layer) having a solid concentration of 35% by weight.

(2) Preparation of liquid B (coating liquid for forming a low refractive index layer) was diluted with 10 parts by weight of a trifunctional acrylate monomer in a mixed solvent of MIBK/1-methoxy-2-propanol (weight ratio 1/1) Pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., trade name "ARONIX M-305", solid concentration 100%), 142 parts by weight of methyl isobutyl ketone (MIBK) dispersion of porous cerium oxide particles ( Catalyst Chemicals Co., Ltd., trade name "ELCOM RT-1002SIV", solid content concentration: 21% by weight, porous cerium oxide particles: specific gravity 1.8, refractive index 1.30, average particle diameter 60 nm), 0.5 parts by weight 2-methyl-1-[4-(methylthio)phenyl]-2-morpholine-propan-1-one which is a photopolymerization initiator (manufactured by Ciba Specialey Chemicals, trade name (IRGACURE 907), solid form a concentration of 100% by weight, and 0.005 parts by weight of a mixture of denatured polydimethyl siloxane (manufactured by Toray Dow Corning Co., Ltd., trade name "SH28PA", solid content concentration: 100%), which is a horizontal agent, is used to prepare a solid component. Liquid B (coating liquid for forming a low refractive index layer) having a concentration of 2.5% by weight.

(3) Preparation of antireflection film The liquid A obtained in the above (1) was applied to triethylsulfonium cellulose having a thickness of 80 μm as a substrate film using Meyer bar No. 8 (Meyer bar No. 8). The surface of the film "Fuji Photo Film (stock), trade name (T-80UZ)" has a thickness of 3 μm after hardening. Next, after drying at 90 ° C for 1 minute, ultraviolet rays were irradiated at a light amount of 80 mJ/cm ^{2 to} make the hardening semi-cured.

Next, the liquid B obtained in the above (2) was applied to the semi-cured surface using Meyer Rod No. 4, and the thickness after hardening was 0.1 μm. Next, after drying at 80 ° C for 1 minute, the ultraviolet rays were irradiated with a light amount of 350 mJ/cm ² to completely harden, and a hard coating layer having a refractive index of 1.50 and a refractive index of 1.36 were sequentially formed on the triacetyl cellulose film. The refractive index layer is used to form an antireflection film.

The physical properties of the antireflection film thus obtained are shown in Table 1.

In addition, the thickness of each coating layer was measured by "MCPD-2000" manufactured by Otsuka Electronics Co., Ltd., and the refractive index was Abbe refractometer (Na light source, wavelength: about 590 nm) manufactured by Atago Co., Ltd. The measurement was carried out. (the same below)

Example 2

An antireflection film was produced in the same manner as in Example 1 except that the amount of the antistatic agent "Colcoat NR-121X-9IPA" in Example 1 (1) was changed to 60 parts by weight. The hard coating layer has a refractive index of 1.49.

The physical properties of the antireflection film thus obtained are shown in Table 1.

Example 3

An antireflection film was produced in the same manner as in Example 1 except that the amount of the MIBK dispersion "ELCOM RT-1002SIV" of the porous ceria particles in Example 1 (2) was changed to 120 parts by weight. The refractive index of the low refractive index layer was 1.40.

The physical properties of the antireflection film thus obtained are shown in Table 1.

Comparative example 1

An antireflection film was produced in the same manner as in Example 1 except that the antistatic agent was not used in the preparation of the liquid A in Example 1 (1). The hard coating layer has a refractive index of 1.49.

The physical properties of the antireflection film thus obtained are shown in Table 1.

Comparative example 2

The coating liquid for forming a hard coating layer was prepared in the same manner as in Example 1 except that the amount of the photopolymerization initiator "IRGACURE 907" was changed to 1.8 parts by weight in the preparation of the liquid A in the first embodiment (1).

Then, the coating liquid for forming a hard coating layer was applied to the surface of a triacetonitrile cellulose film "T-80UZ" (outward) having a thickness of 80 μm as a base film, using Meyer Bar No. 8. Its hardened thickness is 3 μm. Next, after drying at 90 ° C for 1 minute, the ultraviolet rays were irradiated with a light amount of 350 mJ/cm ² to completely cure the film, and a hard coating film was produced.

The physical properties of the hard coating film thus obtained are shown in Table 1.

As can be seen from the first table, any of the antireflection films of the present invention (Examples 1 to 3) is excellent in antireflection property, and has low surface resistance after initial stage and ethanol wiping, and has excellent antistatic property and solvent resistance. It is also excellent in abrasion resistance.

On the other hand, in Comparative Example 1, since the antistatic agent was not contained in the hard coating layer, the surface resistivity after initial wiping and ethanol wiping was high, and the antistatic property was inferior. Further, in Comparative Example 2, since the low refractive index layer was not provided, the antireflection property was poor, and the surface resistivity after wiping with ethanol was high, and the solvent resistance was poor.

[Possibility of application in industry]

The antireflection film of the present invention can effectively prevent light reflection on the surface of an image display element, has an excellent antistatic effect for suppressing adhesion of dust, has excellent durability and abrasion resistance, and is excellent in solvent resistance, and is suitable for, for example, a PDP or a CRT. , LCD and other displays.

Claims (2)

An antireflection film characterized by having (A) a hardening resin containing a trifunctional acrylate monomer irradiated with an active energy ray (except a resin containing a fluorine atom), and at least on one side of the substrate film, and 2 to 25% by weight of a polymer type cationic antistatic agent containing one or more quaternary ammonium salt groups having a thickness of 1 to 20 μm, and (B) containing activated light rays a hardening resin of a functional acrylate monomer (excluding a resin containing a fluorine atom), and a porous refractive index layer of 30 to 80% by weight of porous cerium oxide particles having a thickness of 0.05 to 0.3 μm and a surface resistivity of 5 ×10 ¹² Ω/□ or less. For example, in the antireflection film of claim 1, the porous cerium oxide particles of the (B) layer have a specific gravity of 1.7 to 1.9, a refractive index of 1.25 to 1.36, and an average particle diameter of 20 to 100 nm.