KR101697779B1 - Optical film - Google Patents

Abstract

An object of the present invention is to provide an optical film which is highly suitable for a polarizing plate or a touch panel, excellent in scratch resistance, good in both image sharpness and proper light-shielding property, , A hard coat layer is formed on at least one surface of a transparent base film by a coating composition containing an active energy ray curable compound and organic fine particles and the external haze value of the hard coat layer is 7% A haze value of 1 to 12%, and a 60-degree specular gloss of 100 to 150.

Description

Optical film {OPTICAL FILM}

The present invention relates to an optical film, and more particularly, to an optical film which is excellent as a polarizing plate and a touch panel, has excellent scratch resistance, and has good image sharpness and proper light-shielding property.

In a display such as a cathode ray tube (CRT), a liquid crystal display (LCD), or a plasma display (PDP), light may be incident on the screen from the outside and may be reflected to make the display image difficult to see. In recent years, it has become more and more important to solve the above problem in accordance with the increase in the size of the display. One of means for solving this problem is to use a member having a flash-resistant hard coat layer. (1) a method of roughening the surface by a physical method at the time of curing to form a hard coat layer, (2) a method of forming a hard coat layer for hard coat layer formation, (3) a method of incorporating two components that are incompatible with the hard coat agent for forming the hard coat layer, and a method of using the phase separation of these components Type. All of these forms fine irregularities on the surface, thereby suppressing the regular reflection of external light and preventing the projection of external light such as a fluorescent lamp. Among them, a method of mixing the filler into the hard coat agent of (2) is the mainstream. As the filler, inorganic fine particles originally represented by silica were generally used. The reason why the silica particles are used is that the whiteness of the obtained hard coat film can be suppressed to a low level and the hardness of the hard coat layer is not reduced due to insufficient hardening.

On the other hand, as an example using organic fine particles as a filler, Patent Document 1 discloses, for example, a method in which an antireflective layer made of resin beads having a refractive index of 1.40 to 1.60 and an ionizing radiation layer essentially composed of an ionizing radiation- Discloses an antiglare film, and Patent Document 2 discloses a film comprising a transparent base film and an antiglare layer containing two or more kinds of light-transmitting fine particles in a light-transmitting resin, wherein the light-transmitting fine particles and the light- Is 0.03 or more and 0.20 or less, and an uneven shape is formed on the surface of the antiglare layer by the above-mentioned two or more kinds of light-transmitting fine particles.

As described above, various antiglare films have been studied so far. However, for the purpose of making the image projected from the screen clearly visible, it has been disadvantageous to form a flash-resistant hard coat layer. The anti-glare hard coat layer has a property of diffusing the transmitted light due to the surface irregularities, resulting in poor image clarity and deteriorating the visibility.

Japanese Unexamined Patent Publication No. 6-18706 Japanese Patent No. 3515401

An object of the present invention is to provide an optical film that is excellent in scratch resistance, has good image clarity, and has excellent antifogging properties, which is suitable for a polarizing plate or a touch panel, which has been made under such circumstances.

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted intensive studies in order to achieve the above object and as a result have found that a hard coat layer is formed on at least one surface of a transparent base film by a coating composition containing an active energy ray curable compound and organic fine particles, It has been found that the object can be achieved by setting the outer haze value and the inner haze value of the hard coat layer to a specific range and setting the 60 占 specular gloss to a specific range. The present invention has been completed based on such insights.

That is,

(1) A hard coat layer is formed on at least one surface of a transparent base film by a coating composition containing an active energy ray-curable compound and organic fine particles, and an external haze value of the hard coat layer is 7% or less and an internal haze value 1 to 12% and a 60 占 specular gloss of 100 to 150,

(2) the optical film according to the above item (1), wherein the hard coat layer has a thickness of 7 to 20 占 퐉,

(3) The optical film according to (1) or (2) above, wherein the average particle diameter of the organic fine particles is smaller than the thickness of the hard coat layer,

(4) The optical film according to any one of (1) to (3), wherein the low refractive index layer is laminated on the hard coat layer,

(5) The optical film according to any one of (1) to (4), wherein a pressure-sensitive adhesive layer is laminated on the side of the transparent base film on which the hard coat layer is not formed,

(6) An optical film according to any one of (1) to (4), wherein a hard coat layer is laminated on a surface of the transparent base film on which the hard coat layer is not formed.

As a preferred form of the optical film of the present invention,

(a) an optical film in which the total phase clarity of the five types of slits is 300 or more,

(b) the spherical particles having an average particle size of 1 to 15 탆, wherein the organic fine particles are an optical film containing 1 to 15 parts by mass based on 100 parts by mass of the cured resin in the hard coat layer,

(c) an optical film having a specific gravity of the active energy ray curable compound of at least 0.15 or more greater than the specific gravity of the organic fine particles at a temperature of 25 ° C,

(d) an optical film having a refractive index of 1.43 or less and a thickness of 50 to 200 nm of the low refractive index layer of the item (4)

(e) an optical film for a touch panel or a polarizing plate.

According to the present invention, the outer haze value and the inner haze value of the hard coat layer formed on at least one surface of the transparent base film can be set within a specific range, and the 60 ° mirror surface gloss can be set within a specific range, It is possible to provide an optical film which is highly suitable for use as a panel or the like, has excellent scratch resistance, and has good image clarity and appropriate light-shielding properties.

In the optical film of the present invention, a hard coat layer is formed on at least one surface of a transparent base film by a coating composition containing an active energy ray-curable compound and organic fine particles, and the outer haze value and the inner haze value And the specular gloss is in the range shown below, and the specular gloss at 60 ° is in the range shown below.

[Coating composition]

The coating composition in the present invention contains an active energy ray-curable compound and organic fine particles.

(Active energy ray curable compound)

As the active energy ray curable compound, a multifunctional (meth) acrylate monomer and / or a (meth) acrylate based prepolymer can be used.

In the present invention, the active energy ray refers to those having energy in the electromagnetic wave or charged particle beam, that is, ultraviolet rays, electron beams, and the like.

<Multifunctional (meth) acrylate monomer and / or (meth) acrylate-based prepolymer>

Examples of the polyfunctional (meth) acrylate monomer include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) (Meth) acrylate, glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl Acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, isocyanurate di (meth) acrylate, (Meth) acrylate, propylene oxide-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylol propane tri (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (metha) acrylate, and the like. And polyfunctional (meth) acrylates. These monomers may be used alone or in combination of two or more.

On the other hand, examples of the (meth) acrylate-based prepolymer include polyester acrylate-based, epoxyacrylate-based, urethane acrylate-based, polyol acrylate-based and the like. Examples of the polyester acrylate-based prepolymer include a polyester oligomer obtained by esterification of a hydroxyl group of a polyester oligomer having a hydroxyl group at the end of its ends with (meth) acrylic acid obtained by condensation of a polyhydric carboxylic acid and a polyhydric alcohol, Can be obtained by esterifying the hydroxyl group at the terminal of the oligomer obtained by adding an alkylene oxide to (meth) acrylic acid.

The epoxy acrylate-based prepolymer can be obtained, for example, by reacting (meth) acrylic acid with an oxirane ring of a relatively low molecular weight bisphenol-type epoxy resin or novolak-type epoxy resin to effect esterification. The urethane acrylate prepolymer can be obtained by, for example, esterifying a polyurethane oligomer obtained by a reaction of a polyether polyol or polyester polyol with a polyisocyanate with (meth) acrylic acid. The polyol acrylate-based prepolymer can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid. These prepolymers may be used singly or in combination of two or more, and may be used in combination with the polyfunctional (meth) acrylate-based monomer.

In the present invention, as the active energy ray curable compound, the following silica-based fine particles may be used in combination with the polyfunctional (meth) acrylate monomer and / or the (meth) acrylate-based prepolymer.

&Lt; Silica-based fine particles &

As the silica-based fine particles, colloidal silica fine particles and / or silica fine particles having a surface functional group can be used.

The colloidal silica fine particles have an average particle diameter of about 1 to 400 nm. As the silica fine particles having a surface functional group, for example, silica fine particles having a group containing a (meth) acryloyl group as a surface functional group Silica fine particles are sometimes referred to as silica fine particles).

The reactive silica fine particles can be obtained, for example, by reacting a silanol group on the surface of fine silica particles having an average particle size of about 0.005 to 1 탆 with a polymerizable unsaturated group-containing organic compound having a functional group capable of reacting with the silanol group have. The polymerizable unsaturated group includes, for example, a radical polymerizable (meth) acryloyl group.

Examples of such compounds include acrylic acid, acrylic acid chloride, 2-isocyanatoethyl acrylate, glycidyl acrylate, 2,3-iminopropyl acrylate, 2-hydroxyethyl acrylate, acryloyloxypropyltrimethoxy Silane and the like, and methacrylic acid derivatives corresponding to the acrylic acid derivatives thereof. These acrylic acid derivatives and methacrylic acid derivatives may be used alone or in combination of two or more.

The thus obtained fine silica particles to which the polymerizable unsaturated group-containing organic compound is bonded are crosslinked and cured by irradiation with an active energy ray as an active energy ray curing component.

These reactive silica fine particles have the effect of improving the scratch resistance of the resulting optical film.

Examples of the active energy ray curable compound containing a compound obtained by bonding an organic compound having a polymerizable unsaturated group to such silica fine particles include products available under the trade names &quot; OPSTAR Z7530 &quot;, &quot; OPSTAR Z7524 , And "Obstar TU4086" are commercially available.

In the present invention, the content of the silica-based fine particles is usually about 5 to 90% by mass, preferably 10 to 70% by mass, in the solid content of the active energy ray curable compound (containing silica-based fine particles).

(Organic fine particles)

Examples of the organic fine particles to be used in the coating composition of the present invention include silicon-based fine particles, melamine-based resin fine particles, acrylic-based resin fine particles (for example, polymethylmethacrylate-based fine particles ), Acrylic-styrene copolymer fine particles, polycarbonate fine particles, polyethylene fine particles, polystyrene fine particles, benzoguanamine type resin fine particles, and the like. The shape of the organic fine particles to be used in the present invention is not particularly limited, but from the viewpoint of raising the reproducibility of the antiglare performance, the spherical shape is preferable because homogeneous light scattering state is obtained. From the same viewpoint, it is particularly preferable that the organic fine particles have a narrow particle size distribution. From the viewpoint of the anti-glare performance, the average particle size of the organic fine particles is preferably 1 to 15 mu m, particularly preferably 2 to 5 mu m, and from the same viewpoint, the particle size distribution is determined by the coulter counter method It is preferable that the mass fraction of the particle diameter of not less than 50% of the particle diameter of the peak top measured by the mass spectrometry is not less than 70% of the whole.

In the present invention, these organic fine particles may be used singly or in combination of two or more kinds.

The blending amount is preferably 0.1 part by mass or more based on 100 parts by mass of the solid content of the above-mentioned active energy ray curable compound (when silica fine particles are used, it is contained) from the viewpoint of exhibiting the antiglare performance . Further, from the viewpoint of suppressing the external haze value of the resulting optical film to 7% or less, the content of the organic fine particles is preferably 15% by weight based on 100 parts by weight of the solid content of the above-mentioned active energy ray curable compound (when silica fine particles are used, By mass or less. From this point of view, the content of the organic fine particles in 100 parts by mass of the solid content of the active energy ray-curable compound (when using the silica-based fine particles) is more preferably 1 to 10 parts by mass, Particularly preferably 7 parts by mass.

In the present invention, since the organic fine particles are localized near the surface of the hard coat layer to improve the antiglare performance, the specific gravity of the active energy ray curable compound (when silica fine particles are used, it is contained) Is larger than the specific gravity of the organic fine particles by 0.15 or more. If the specific gravity difference is less than 0.15, the ratio of the organic fine particles present in the vicinity of the surface of the hard coat layer is lowered, and the desired antiglare performance can hardly be obtained. The specific gravity difference is more preferably 0.20 or more, and still more preferably 0.25 or more.

If the specific gravity difference is too large, the volume of the organic fine particles seen from the surface of the hard coat layer becomes excessively large. As a result, the concavity and convexity of the surface of the hard coat layer becomes excessively large, have. Therefore, the specific gravity difference is preferably less than 0.40, more preferably less than 0.38, still more preferably less than 0.35.

The specific gravity of the active energy ray-curable compound at a temperature of 25 캜 is a value measured according to the method of measuring specific gravity by a light scattering bottle of JIS Z 8804 before curing by energy ray irradiation. The specific gravity of the organic fine particles at a temperature of 25 캜 is a value measured in accordance with the specific gravity measuring method according to JIS Z 8807-1976.

On the other hand, in order to realize the technical idea of the present invention that the deterioration of the antiglare property due to the reduction of the external haze value is compensated by the internal haze, it is preferable to use the above- It is preferable to form the refractive index difference at a predetermined value or more. That is, the difference in the refractive index is preferably 0.02 to 0.5, particularly preferably 0.03 to 0.1. If the difference in the refractive index is 0.02 or more, the internal haze value can be 1% or more, and if the difference in refractive index is 0.5 or less, the internal haze value can be suppressed to 12% or less.

The refractive index of the organic fine particles is a calculated value from the refractive index and the contained mass ratio of the contained monomer based on the composition of the monomer. The refractive index of the active energy ray curable compound is a measurement value according to JIS K 7142 for curing the active energy ray by irradiation.

(Photopolymerization initiator)

In the coating composition of the present invention, a photopolymerization initiator may be contained as desired. Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2 , 2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl- ) Ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2- Aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone Dimethyl ketal, p-dimethylamino benzoic acid And the like.

These compounds may be used alone or in combination of two or more. The compounding amount is usually selected in the range of 0.2 to 10 parts by mass based on 100 parts by mass of the total active energy ray-curable compound. The term "total active energy ray-curable compound" as used herein means that silica-based fine particles are used when reactive silica fine particles are used.

(Antistatic agent)

An antistatic agent may be contained in the coating composition of the present invention as desired. By containing an antistatic agent, dust adhesion of the optical film can be prevented, and the visibility of the optical film can be further enhanced.

Examples of the antistatic agent include tin oxide, antimony doped tin oxide (ATO), indium oxide, tin doped indium oxide (ITO), zinc oxide, aluminum doped zinc oxide, antimony zinc oxide, Various cationic compounds having a cationic group such as quaternary ammonium salts, pyridinium salts and primary to tertiary amino groups, sulfonic acid bases, sulfuric acid ester bases, phosphoric acid ester bases, Anionic compounds having anionic groups such as phosphonic acid and phosphonic acid groups, amphoteric compounds such as amino acid and amino sulfuric acid ester, nonionic compounds such as amino alcohol, glycerin and polyethylene glycol, And metal chelate compounds such as acetylacetonato salts thereof, and the like.

The antistatic agent may be appropriately used in an appropriate range without departing from the scope of the present invention and within the scope of not reducing the effect obtained by the present invention.

(Preparation of Coating Composition)

The coating composition used in the present invention may contain, if necessary, the active energy ray-curable compound, the organic fine particles and the silica-based fine particles, the photopolymerization initiator, the antistatic agent and various additive components, An antioxidant, an ultraviolet absorber, a silane coupling agent, a light stabilizer, a leveling agent, a defoaming agent and the like in a predetermined ratio, and dissolving or dispersing them.

Examples of the solvent include aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, alcohols such as methanol, ethanol, propanol, butanol and propylene glycol monomethyl ether Ketones such as alcohol, acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve.

The concentration and the viscosity of the coating composition thus prepared are not particularly limited and may be suitably selected in accordance with the circumstances.

[Transparent substrate film]

In the optical film of the present invention, the hard coat layer is formed on at least one side of the transparent base film using the coating composition prepared as described above.

The above-mentioned transparent base film is not particularly limited, and can be suitably selected from plastic films known as base materials for conventional hard coat films for optical use. Examples of such plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyethylene films, polypropylene films, cellophane, diacetylcellulose films, triacetylcellulose films, acetylcellulose Polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, A plastic film such as a polyether sulfone film, a polyether imide film, a polyimide film, a fluororesin film, a polyamide film, an acrylic resin film, a norbornene resin film, and a cycloolefin resin film.

These base films may be colored or non-colored, and may be appropriately selected depending on the application. For example, when it is used for protection of a liquid crystal display, a colorless transparent film is very suitable.

The thickness of these base films is not particularly limited and is appropriately selected according to the circumstances, but is usually in the range of 15 to 300 占 퐉, preferably 30 to 200 占 퐉. The substrate film may be subjected to surface treatment on one side or both sides by an oxidation method, a concavo-convex method or the like, if desired, for the purpose of improving the adhesion with the layer formed on the surface. Examples of the oxidation method include a corona discharge treatment, a plasma treatment, a chromic acid treatment (wet type), a flame treatment, a hot air treatment, an ozone / ultraviolet ray irradiation treatment and the like. Examples of the irregularity include sandblasting, And a solvent treatment method. These surface treatment methods are appropriately selected depending on the kind of the plastic film used as the base film, but in general, the corona discharge treatment method is preferably used in view of effects and operability. In addition, a primer layer may be formed.

[Formation of hard coat layer]

The coating composition is coated on at least one side of the transparent substrate film 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, A hard coat layer is formed by applying a coating film to form a coating film, drying the coating film, and irradiating it with an active energy ray to cure the coating film.

Examples of the active energy ray include ultraviolet rays and electron rays. The ultraviolet ray is obtained by a high-pressure mercury lamp, an electrodeless lamp, a metal halide lamp, a xenon lamp, etc., and an irradiation amount is usually 100 to 50 O mJ / cm 2. The electron beam is obtained by an electron beam accelerator or the like, 150 to 350 kV. Of these active energy rays, ultraviolet rays are particularly suitable. When an electron beam is used, a cured film can be obtained without adding a photopolymerization initiator.

In the present invention, it is very important that the hard coat layer thus formed has a thickness larger than the average particle diameter of the organic fine particles used, and therefore, it is preferably 7 to 20 占 퐉, more preferably 10 to 15 占 퐉.

By setting the film thickness of the hard coat layer larger than the average particle size of the organic fine particles, the organic fine particles are fixed in a so-called excited state in which the surface of the transparent base film is not in contact with the hard coat layer. It can be made gentle. As a result, it is effective to set the external haze value of the obtained optical film to 7% or less and the 60 ° mirror surface gloss to 100 or more.

From this point of view, the film thickness of the hard coat layer is preferably 1.5 times or more of the average particle diameter of the organic fine particles, more preferably 2.0 times or more. In consideration of setting the internal haze value of the obtained optical film at 1% or more, it is preferable that the film thickness is less than 10 times the average particle diameter.

[Optical film]

(Optical characteristics)

The optical film of the present invention formed in this manner has the characteristics of having good image clarity and proper light-shielding property because the hard coat layer has the following optical properties.

The external haze value of the hard coat layer is preferably 7% or less from the viewpoint of image clarity and visibility, and more preferably 1.0% or more, and more preferably 3.5 to 5.0% from the viewpoint of the dispersibility. On the other hand, the internal haze value is 1 to 12%, preferably 5 to 12%, more preferably 8 to 12% from the viewpoint of enhancing anti-glare while maintaining image clarity.

Also, the internal haze value represents a haze value attributed only to the internal light scattering, and the external haze value represents a haze value attributed only to the light scattering caused by the irregularities of the surface, and the total haze value represents the total of the internal haze value and the external haze value. The total haze value corresponds to a value obtained by subtracting the haze value according to JIS K 7136 of the transparent base film as the constituent member of the optical film from the haze value according to JIS K 7136 of the optical film.

Hereinafter, a method of calculating the internal haze value, the external haze value, and the total haze value will be described.

&Lt; calculation of internal haze value, external haze value and total haze value of hard coat layer >

First, in accordance with JIS K 7136, the haze value of the optical film of the present invention and the haze value of the same transparent base film are measured.

A value obtained by subtracting the haze value of the transparent base material film from the haze value of the optical film is taken as the total haze value.

Next, a transparent pressure-sensitive adhesive sheet having a thickness of 20 占 퐉 is stuck to the hard coat layer side of the optical film to obtain a sample for calculating the internal haze value. The haze value of the above-mentioned transparent pressure sensitive adhesive sheet and the haze value of the sample for calculating the internal haze value are measured according to JIS K 7136.

The value obtained by subtracting the haze value of the transparent pressure-sensitive adhesive sheet and the haze value of the single transparent base film from the haze value of the sample for calculating the internal haze value is defined as the internal haze value of the hard coat layer of the optical film.

Finally, the value obtained by subtracting the internal haze value from the total haze value is defined as an external haze value.

Further, since the haze value of the above-mentioned transparent pressure sensitive adhesive sheet is not deducted from the internal haze value, the external haze value, and the total haze value because it is subtracted in the calculation process as described above, there is no particular limitation, It is preferable to use a haze value of less than 5%.

In the optical film of the present invention, the 60 占 specular gloss measured in accordance with JIS K 7105 is in the range of 100 to 150, preferably 100 to 140, and more preferably 120 to 130.

In the case of an optical film having a conventional antiglare property, it is preferable that the 60-degree mirror polish degree is 80 or less, and it is too high in the range of the mirror polish degree of 60 占 of the present invention. However, if the outer haze value and the inner haze value are designed so as to fall within the above-mentioned range and then the 60 ° mirror surface glossiness is designed in the above-mentioned range, the degree of visibility in the vertical direction, As a result, it has been found that an optical film excellent in anti-glare properties can be obtained

The sum of the image clarity of five kinds of slits measured in accordance with JIS K 7374 is usually 300 or more, preferably 300 to 350, and more preferably 320 to 350. As described above, the optical film of the present invention has high image clarity and is excellent in visibility.

The total light transmittance measured in accordance with JIS K 7136 is usually 90% or more.

Details of the measurement method of each optical characteristic will be described later.

(Surface resistivity)

In the optical film of the present invention, it is preferable that the surface resistivity measured according to JIS K 6911 is 5 x 10 ⁹ ? /? Or less. This is because the surface resistivity can prevent the adherence of dust and maintain the visibility of the optical film of the present invention over a long period of time. The lower limit is not particularly limited, but is usually 1 x 10 ⁷ ? /? Or more.

(effect)

A more preferable structure and effects of the optical film of the present invention are as follows.

(1) In the present invention, the hard coat layer is formed by using the coating composition adjusted so that the external haze value and the internal haze value of the hard coat layer and the 60 占 specular gloss degree fall within the above-mentioned range, It is possible to obtain an optical film which is very suitable as a film having good image clarity and adequate antiglare property.

(2) By setting the specific gravity difference between the active energy ray-curable compound and the organic fine particles within a specific range, the organic fine particles are localized in the vicinity of the surface of the hard coat layer, and the desired antiglare performance is exhibited. By controlling the above-mentioned specific gravity difference, it becomes possible to control the external haze value and the specular glossiness of 60 占 to a desired value.

(3) By setting the specific gravity difference to a specific range, the organic fine particles are present in the vicinity of the hard coat layer surface even at a film thickness larger than the average particle diameter of the organic fine particles, and the anti- The surface can be obtained.

(4) By using an active energy ray curable compound containing silica-based fine particles, an optical film having a low degree of curing shrinkage and little curl can be obtained. In addition, when an active energy ray curable compound containing silica-based fine particles is used, it becomes possible to design a larger specific gravity difference with the organic fine particles.

(Other function layer)

In the optical film of the present invention, a low refractive index layer can be formed as an antireflection layer on the hard coat layer, if necessary. The low refractive index layer is preferably a layer having a refractive index of 1.43 or less and a thickness of about 50 to 200 nm from the viewpoint of antireflection property.

By forming the antireflection layer, halation of the screen caused by reflection by sunlight, fluorescent lamp or the like is solved, and the reflectance of the surface is suppressed, whereby the total light transmittance is increased and the visibility is improved. Further, depending on the kind of the antireflection layer, the antistatic property can be improved.

In the optical film of the present invention, a hard coat layer can be laminated on the side of the transparent base film on which the hard coat layer is not formed, if necessary. The hard coat layer is preferably a clear hard coat layer.

The clear hard coat layer contains a clear hard coat layer forming material containing a polyfunctional (meth) acrylate monomer and / or a (meth) acrylate based prepolymer as an active energy ray curable compound and, if necessary, a photopolymerization initiator , And then applying it to a predetermined surface of a transparent base film by a conventionally known method, drying it, and then curing it by irradiating with an active energy ray, preferably ultraviolet ray.

The above polyfunctional (meth) acrylate monomer, (meth) acrylate prepolymer and photopolymerization initiator are as described in the above description of the coating composition. The clear hard coat layer forming material may contain various additive components as required.

The thickness of the clear hard coat layer is usually about 2 to 10 mu m, preferably 3 to 6 mu m.

(Pressure-sensitive adhesive layer)

In the optical film of the present invention, a pressure-sensitive adhesive layer for adhering to an adherend such as a liquid crystal display can be formed on the side of the transparent base film on which the hard coat layer is not formed. As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, for example, acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives and silicone pressure-sensitive adhesives, which are suitable for optical applications, are preferably used. The thickness of the pressure-sensitive adhesive layer is usually 5 to 100 占 퐉, preferably 10 to 60 占 퐉.

Further, a release sheet can be formed on the pressure-sensitive adhesive layer, if necessary. Examples of the peeling sheet include those obtained by applying a releasing agent such as a silicone resin to various plastic films such as polyethylene terephthalate and polypropylene. The thickness of the release sheet is not particularly limited, but is usually about 20 to 150 mu m.

Such an optical film having a pressure-sensitive adhesive layer formed thereon is very suitably used as a member for imparting an antiglare performance or scratch-resistant performance to a display such as a CRT, LCD, or PDP, and is particularly suitable for a polarizer- Suitable.

<Examples>

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

The average particle diameter and specific gravity of the organic fine particles, the specific gravity of the active energy ray-curable compound, and the performance of the optical film were determined by the following methods.

&Lt; Organic fine particles &

(1) average particle diameter

The measurement is carried out at 25 캜 by a Coulter counter method using a Coulter counter (manufactured by Beckman Coulter, Inc., device name "Multisizer 3") as a dispersion of ion exchange water at 0.5%.

(2) Specific gravity at 25 ° C

The specific gravity of JIS Z 8807-1976 is measured by means of a grapevine.

<Active Energy ray curable compound>

(3) Specific gravity at 25 캜

Active energy before active energy ray irradiation The specific gravity of JIS Z 8804 is measured by the light scattering type for the ray-curable compound.

When silica-based fine particles are used, the specific gravity of the active energy ray-curable compound in a state containing the silica-based fine particles is measured.

&Lt; Optical film &

(4) Total light transmittance

The total light transmittance of the optical films prepared in Examples and Comparative Examples was measured in accordance with JIS K 7136 using a haze meter "NDH-2000" manufactured by NIPPON DENSHOKU KOGYO CO., LTD.

(5) Internal haze value, external haze value, and total haze value

Using the haze meter &quot; NDH-2000 &quot; manufactured by Nippon Denshoku Kogyo Co., Ltd., in accordance with JIS K 7136, the optical films prepared in Examples and Comparative Examples and the haze Measure the value. In the optical films of Examples 4 to 6, a pressure-sensitive adhesive layer or a clear hard coat layer was also laminated on the side opposite to the side where the hard coat layer of the transparent base film was formed, but the inside haze value, the external haze value, The calculation of the haze value is performed by using an optical film before these layers are laminated.

The total haze value of the hard coat layer of the optical film is calculated by subtracting the haze value of the transparent base film from the haze value of the optical film obtained by the above measurement.

Subsequently, 2 parts by mass of an isocyanato crosslinking agent (trade name "BHS-8515" manufactured by TOYOTO INC., Trade name; product of "BHS-8515") and 100 parts by mass of toluene were added to 100 parts by mass of an acrylic pressure- sensitive adhesive (product of NIPPON CARBIDE, 100 parts by mass were added to prepare a pressure-sensitive adhesive solution. A pressure-sensitive adhesive sheet was prepared by applying a pressure-sensitive adhesive solution to a polyethylene terephthalate film (trade name: A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 50 占 퐉 so that the thickness after drying became 20 占 퐉 and drying at 100 占 폚 for 3 minutes.

The prepared transparent pressure sensitive adhesive sheet was stuck to the hard coat layer side of the optical film and used as a sample for calculating the internal haze value. The haze value of each of the transparent pressure-sensitive adhesive sheet and the sample for calculating the internal haze value is measured in accordance with JIS K 7136 as described above.

The internal haze value of the hard coat layer of the optical film is calculated by subtracting the haze value of the transparent pressure sensitive adhesive sheet and the haze value of the transparent base film from the haze value of the sample for calculating the internal haze value.

Finally, the external haze value of the hard coat layer of the optical film is calculated by subtracting the internal haze value from the total haze value.

(6) Evaluation of flammability

A sample in which an optical film is stuck to an acrylic resin blackboard (manufactured by Sumitomo Chemical Co., Ltd.) with an acrylic adhesive is visually observed under a fluorescent lamp, and the retardation is evaluated according to the following criteria.

A: There is no flammability.

B: It has flammability.

C: It has flammability, but is whitened.

(7) 60 ° specular gloss

The measurement is carried out in accordance with JIS K 7105 using a gloss meter &quot; VG2000 &quot; manufactured by Nippon Denshoku Kogyo Co.,

(8) Phase Sharpness

Measurement is carried out in accordance with JIS K 7374, using a mapping device "ICM-10P" manufactured by Suga Shikenki Co., Ltd. The total value of five types of slits (slit width: 0.125 mm, 0.25 mm, 0.5 mm, 1 mm and 2 mm) is shown in terms of image clarity.

(9) Anti-glare property

A polarizing plate prepared using the optical films obtained in Examples and Comparative Examples was provided on the surface of the surface of the liquid crystal display &quot; AQUOS LC-20AX5 &quot; manufactured by Sharp Corporation, on which the polarizing plate was peeled off, and the luminance was visually observed. The polarizing plate was manufactured by the same method as in Example 1 except that an optical film was laminated on one side of a polarizer in which iodine was adsorbed on stretched polyvinyl alcohol and triacetyl cellulose (hereinafter referred to as "TAC") film (manufactured by KONICA MINOLTA OPTO Co., Trade name &quot; KC8UX2M &quot;).

◎: No flashing of luminance.

○: There is little flash of brightness, but there is no practical problem.

△: There is a problem of practicality because the luminance is slightly flickering.

X: There is a lot of flashing of brightness, so that it fails.

(10) Character Visibility

The optical films obtained in Examples and Comparative Examples were laminated on the surface of a liquid crystal display &quot; AQUOS LC-20AX5 &quot; manufactured by Sharp Corporation, and the character visibility of the liquid crystal display was evaluated according to the following criteria.

◎: Good visibility.

○: Visibility is slightly lower, but practically no problem.

△: Visibility is slightly deteriorated, and there is a practical problem.

X: Bad visibility, fail.

(11) Surface resistivity

Measured using a parallel electrode connected to a resistivity meter &quot; MCP-HT450 &quot; manufactured by Mitsubishi Chemical Corporation in accordance with JIS K6911.

(12) Reflectance

The reflectance at wavelengths of 500 nm, 600 nm, and 700 nm is measured using a spectrophotometer ("UV-3101PC" manufactured by Shimadzu Corporation).

(13) Evaluation of surface condition

The surface of the hard coat layer was visually observed and the unevenness of the roughness of the hard coat layer was evaluated according to the following criteria.

?: The entire surface of the hard coat layer is uniformly visible.

X: On the surface of the hard coat layer, a portion having high flicker and a portion having a low flicker are mixed, and thus the entire portion appears uneven.

(14) Thickness of hard coat layer

The thicknesses of the optical films prepared in Examples and Comparative Examples and the transparent base films used in the production of the optical films were measured with a static pressure meter ("MH-15M" manufactured by Nikon Corporation) Is set as the thickness of the hard coat layer.

(15) Refractive index

ㆍ Organic fine particles

Based on the composition of the monomer of the organic fine particles, from the refractive index and contained mass ratio of the contained monomer.

ㆍ Refractive index of active energy ray curable compound

Coatings for Coatings 1, 2 and 6 for Hard Coat Layer Coating agents without addition of organic fine particles were prepared, respectively, and hard coat layers corresponding to those of Example 1 were prepared. The refractive index of the hard coat layer was measured according to JIS K 7142 by an Abbe refractometer (manufactured by Atago Co., Ltd., Abbe refractometer 4T, Na light source, wavelength: about 590 nm). The measured value is taken as the refractive index of the active energy ray curable compound.

(16) Evaluation of prevention of dust adhesion

The optical films obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were allowed to stand in a room where people were coming and going for one month. After one month, the dust adhesion on the surface of the hard coat layer was visually evaluated according to the following criteria.

○: No adhesion of dust was observed at all.

X: Dust adhered to one side of the hard coat layer.

(Preparation Example 1 Hard Coat Layer Coat First)

As the active energy ray curable compound, a hard coat agent (product name: "UV-ASHC", product of Nippon Kasei Co., Ltd., solid content concentration of 70% by mass, total active energy ray curable compound of 65% 100 parts by mass of a propylene glycol monomethyl ether, 30 parts by mass of a propylene glycol monomethyl ether, a specific gravity of a solid component of 1.35, and a refractive index after a curing of 1.53; and 0.13 parts by mass of an acrylic fine particle (trade name: SX500HMR, manufactured by SOKEN KAGAKU Co., 3.75 parts by mass with a specific gravity of 1.10 and a refractive index of 1.57] and 90 parts by mass of propylene glycol monomethyl ether as a diluting solvent were uniformly mixed to prepare a hard coat layer 1 having a solid content of 40% by mass.

(Preparation Example 2: Antireflection layer coating: second)

100 parts by mass of an ultraviolet (UV) curing hard coat agent (trade name: Beam Set 575CB, product of Arakawa Chemical Industries, Ltd., solid content 100%), methyl isobutyl ketone (MIBK) And 80 parts by mass of a dispersing element (trade name: ELCOM RT-1002SIV, solid content 21% by mass, porous silica particles: specific gravity 1.8, refractive index after curing 1.30, average particle diameter 60 nm) Was diluted with MIBK to a solid content concentration of 2% by mass to prepare a second coat for antireflection layer.

(Preparation Example 3: Coating for pressure-sensitive adhesive layer third)

A pressure-sensitive adhesive composition of the following composition was mixed to prepare a pressure-sensitive adhesive layer-forming third layer.

&Lt; Composition of pressure-

Acrylic copolymer 100 parts by mass / ultraviolet curable polyfunctional acrylate 25 parts by mass / photopolymerization initiator 1 part by mass / isocyanate crosslinking agent 2 parts by mass

Acrylic copolymer: butyl acrylate / methyl acrylate / acrylic acid (weight ratio 77: 20: 3), weight average molecular weight 80,000

Ultraviolet curable polyfunctional acrylate: tris (acryloxyethyl) isocyanurate, molecular weight 578 (trade name: ARONIX M-315, manufactured by TOAGOSEI)

Photopolymerization initiator: A 1: 1 mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio (IRUGACURE 500, trade name, product of CIBA SPECIALTY CHEMICALS)

Isocyanate cross-linking agent: Trimethylolpropane-modified trilene diisocyanate [product of NIPPON POLYURETHANE CO., LTD., Trade name &quot; Colonate L &quot;

(Preparation Example 4 Clear Hard Coat Layer Coat No. 4)

(Product name: Beam Set 575CB, manufactured by Arakawa Chemical Industries, Ltd., 95 mass% of polyurethane acrylate, 15 mass% of photopolymerization initiator, 100 mass% of solid content) of an ultraviolet (UV) curing type hard coat , And 150 parts by mass of propylene glycol monomethyl ether were uniformly mixed to prepare a coat 4 for a clear hard coat layer having a solid content of about 40% by mass.

(Preparation Example 5: coat for PMMA sheet No. 5)

, And a coating solution for a PMMA sheet (5) comprising an ethyl acetate solution having a concentration of 19 mass% of polymethyl methacrylate (PMMA) (weight average molecular weight: about 110,000, molecular weight distribution: about 2.3) was prepared.

(Preparation Example 6 Hard Coat Layer Coat No. 6)

(Manufactured by JSR Corporation, trade name: "Obstar Z7524", solid content concentration of 70% by mass, and reactive silica fine particles and polyfunctional acrylate as a compound comprising a silica fine particle and an organic compound having a polymerizable unsaturated group bound thereto) 100 parts by mass of an active energy ray curable compound containing 5 mass% of a photopolymerization initiator, 5 mass% of a photopolymerization initiator, 30 mass% of methyl ethyl ketone, a specific gravity of a solid fraction of 1.51, and a refractive index after curing of 1.50) ) Product, "MX-500", average particle diameter 5 μm, specific gravity 1.19, refractive index 1.49], and 90 parts by mass of propylene glycol monomethyl ether as a diluting solvent were mixed uniformly to obtain a hard coat layer Coat No. 6 was prepared.

(Preparation Example 7 Hard Coat Layer Coat No. 7)

(Manufactured by DAINICHI SEIKA CO., LTD., Trade name &quot; Seika Beam EXF L-203 (MBS1) &quot;) having a solid content concentration of 70 mass , 60% by mass of an active energy ray curable compound containing a reactive monomer and a polyfunctional acrylate, 3% by mass of photopolymerization initiator, 7% by mass of amorphous silica and 30% by mass of propylene glycol monomethyl acetate] And 90 parts by mass of glycol monomethyl ether were uniformly mixed to prepare a hard coat layer coat No. 7 having a solid content of about 40% by mass.

(Preparation Example 8 Hard Coat Layer Coating No. 8)

(Trade name: HCA-150D, manufactured by TOKUSHIKI CO., LTD.) Having a solid content concentration of 70% by mass and a reactive monomer containing a reactive monomer and a polyfunctional acrylate dispersed in an amorphous silica having an average particle diameter of about 2 μm , 100 parts by mass of an active energy ray-curable compound (60% by mass, photopolymerization initiator: 3% by mass, amorphous silica: 7% by mass, propylene glycol monomethyl acetate: 30% by mass), and propylene glycol monomethyl ether as a diluting solvent (90% A hard coat layer coat No. 8 having a solid content of about 40% by weight was prepared.

Example 1

The hard coat layer coat first obtained in Preparation Example 1 was coated on the surface of a polyethylene terephthalate (PET) film (product of Toyoboseki Co., Ltd., trade name &quot; PET100A4300 &quot;) having a thickness of 100 mu m as a transparent base film, In a mayer bar. After drying for 1 minute in an oven at 70 deg. C, a hard coat layer was formed by irradiating ultraviolet light having a light amount of 300 mJ / cm2 in a high-pressure mercury lamp to produce an optical film.

Table 1 shows the performance of this optical film.

Example 2

The procedure of Example 1 was repeated except that a triacetylcellulose (TAC) film (trade name: TAC-TD80UL (H), manufactured by Fuji Film Co., Ltd.) Respectively.

Table 1 shows the performance of this optical film.

Example 3

On the hard coat layer formed in Example 2, the antireflection coat 2 obtained in Preparation Example 2 was applied with MeiBARO to a thickness of 0.1 mu m after curing. After drying for 1 minute in an oven at 70 deg. C, a high-pressure mercury lamp was irradiated with ultraviolet light having a light quantity of 30 mJ / cm2 to prepare an optical film having a low refractive index layer.

Table 1 shows the performance of this optical film.

Example 4

The pressure-sensitive adhesive coat layer 3 obtained in Preparation Example 3 was applied onto the surface of the PET film as the transparent substrate film obtained in Example 1 on which the hard coat layer was not formed, Mu m, respectively. After drying for 1 minute in an oven at 70 deg. C, a high pressure mercury lamp was irradiated with ultraviolet light having a light quantity of 30 mJ / cm2 to prepare an optical film having a pressure-sensitive adhesive layer.

Table 1 shows the performance of this optical film.

Example 5

The clear hard coat layer coat 4 obtained in Preparation Example 4 was coated on the side of the PET film which was the transparent substrate film obtained in Example 1 on which the hard coat layer was not formed, Mu] m. After drying in an oven at 70 deg. C for 1 minute, an ultraviolet ray having a light intensity of 30 mJ / cm2 was irradiated from a high-pressure mercury lamp to produce an optical film having a clear hard coat layer on the opposite side of the hard coat layer having antiglare performance.

Table 1 shows the performance of this optical film.

Example 6

As the process film, the coat 5 for a PMMA sheet obtained in Preparation Example 5 was applied onto an PET film ("Diafoil T-100" (registered trademark), available from Mitsubishi Plastics Corporation) And then dried at 100 DEG C for 1 minute to form a PMMA layer to be a transparent base film.

Next, the first coat for hard coat layer obtained in Preparation Example 1 was applied on the PMMA layer so that the thickness after drying was 8 탆, and then irradiated with ultraviolet rays at a light quantity of 300 mJ / cm 2 to form a hard coat layer . Next, a protective film (trade name: "SPF / A1A", product of Lintec Co., Ltd., PET protective film) having a thickness of 20 μm was stuck to the surface of the hard coat layer.

Next, the pressure-sensitive adhesive layer coat 3 obtained in Preparation Example 3 was applied onto the release-treated surface of a PET release film (trade name: SP-PET381031, manufactured by LINTEC CO., LTD.) Having a thickness of 38 μm And then dried to form a pressure-sensitive adhesive layer.

Finally, the "Diafoil T-100" (registered trademark) of the above-mentioned process film was peeled off and bonded to the exposed surface of the PMMA sheet as the transparent base film so that the above-mentioned pressure sensitive adhesive layer was in contact with the pressure sensitive adhesive layer / PMMA sheet / Layer optical film having a three-layer laminated structure.

Table 1 shows the performance of this optical film.

Comparative Example 1

An optical film was produced in the same manner as in Example 2 except that the hard coat layer coat No. 6 obtained in Preparation Example 6 was coated with Meiyaroba so that the film thickness after curing was 3.5 占 퐉.

Table 1 shows the performance of this optical film.

Comparative Example 2

An optical film was produced in the same manner as in Example 2 except that the hard coat layer coat 6 obtained in Preparation Example 6 was coated with Meiyaroba so that the film thickness after curing became 4.8 占 퐉.

Table 1 shows the performance of this optical film.

Comparative Example 3

An optical film was produced in the same manner as in Example 2 except that the hard coat layer coating composition 7 obtained in Preparation Example 7 was coated with Meiyaroba so that the film thickness after curing was 5 占 퐉.

Table 1 shows the performance of this optical film.

Comparative Example 4

An optical film was produced in the same manner as in Example 2 except that the coat for hard coat layer 8 obtained in Preparation Example 8 was applied with Meiji bar so that the film thickness after curing was 5 占 퐉.

Table 1 shows the performance of this optical film.

In Table 1, the following can be seen.

All of the optical films (Examples 1 to 6) of the present invention had an outer haze value of 7% or less (3.95 to 5.24%) and an inner haze value of 1 to 12% (10.89 to 11.39%) in the hard coat layer And a 60 占 specular gloss is in the range of 100 to 150 (120.8 to 129.4). In addition, the image clarity is high and exceeds 300. As a result, it has an excellent antifogging property, and is excellent in visibility and anti-glare properties. The state of the hard coat layer is also good.

Example 3 is an optical film in which a low refractive index layer is formed on a hard coat layer and is excellent in antireflection property as compared with the optical film of Example 1. [

On the other hand, Comparative Example 1 is an example in which the average particle diameter of the organic fine particles is larger than the thickness of the hard coat layer, the image clarity is as small as 15.4, and the visibility is extremely poor. In Comparative Example 2, the average particle diameter of the organic fine particles and the thickness of the hard coat layer were almost the same, the visibility was poor and the hard coat layer surface was uneven. Comparative Example 3 is a type (general-purpose type) using a silica gel filler and has low image clarity and low visibility. The comparative example 4 is a type (fixed type) using a silica gel filler and the image clarity is higher than those of the comparative examples 1 to 3, but it is less than 300, and therefore, the visibility is not necessarily good.

The optical film of the present invention has a hard coat layer, is excellent in scratch resistance, has a good image clarity and an appropriate reflectivity, and is particularly suitable as a polarizing plate or a touch panel.

Claims (6)

An organic electroluminescence device comprising an active energy ray curable compound and organic fine particles having an average particle size of 1 to 5 占 퐉 on at least one surface of a transparent base film and having a content of the organic fine particles Is not less than 0.1 parts by mass and not more than 10 parts by mass and a specific gravity of the active energy ray curable compound is at least 0.15 or more greater than the specific gravity of the organic fine particles at a temperature of 25 캜 to form a hard coat layer, Wherein an outer haze value of the coat layer is 1% or more and 7% or less, an inner haze value is 5% to 12%, and a 60 占 specular gloss degree is 100 to 150. The method according to claim 1,
Wherein the hard coat layer has a thickness of 7 to 20 占 퐉. 3. The method according to claim 1 or 2,
Wherein an average particle diameter of the organic fine particles is smaller than a thickness of the hard coat layer. 3. The method according to claim 1 or 2,
Wherein the low refractive index layer is laminated on the hard coat layer. 3. The method according to claim 1 or 2,
Wherein the pressure-sensitive adhesive layer is laminated on a surface of the transparent base film on which the hard coat layer is not formed. 3. The method according to claim 1 or 2,
Wherein a hard coat layer is laminated on the side of the transparent base film on which the hard coat layer is not formed.