KR20130041741A - Optical film, polarizing plate and image display device - Google Patents

Abstract

PURPOSE: An optical film, a polarizing plate and an image display device having the same are provided to have excellent antistatic properties and suppress degradation of the transparency of an antistatic hard coating layer and the generation of an interference fringe. CONSTITUTION: An antistatic agent is not arranged at a surface between a first hard coating layer and a second hard coating layer, which suppresses the drastic change of refractive index difference around the surface. The refractive index of the first hard coating layer changes to approach the refractive index of a light penetrating material from the second hard coating layer, which sufficiently suppresses the generation of an interference fringe by forming an antistatic hard coating layer. The surface does not exist between the first hard coating layer and the second hard coating layer and the antistatic hard coating layer is formed, which improves adhesion.

Description

Optical film, polarizer and image display {OPTICAL FILM, POLARIZING PLATE AND IMAGE DISPLAY DEVICE}

The present invention relates to an optical film, a polarizing plate, and an image display device.

On the image display surface in image display apparatuses, such as a liquid crystal display (LCD), a cathode ray tube display (CRT), a plasma display (PDP), an electroluminescence display (ELD), and a field emission display (FED), it is usual A functional layer provided with a function such as a scratch resistance function is formed. As one of the functional layers, there is an antistatic hard coat layer having a scratch resistance function and an antistatic function (see, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2006-130667).

When forming an antistatic hardcoat layer, the composition for antistatic hardcoat layers containing an antistatic agent is normally apply | coated and dried on a light transmissive base material. Then, the dried antistatic hard coat layer is cured by irradiating ultraviolet rays or the like to form an antistatic hard coat layer.

In the case of using the sole conductive metal oxide particles as the antistatic agent, when the addition amount of the conductive metal oxide particles is small, the conductive metal oxide particles are uniformly dispersed in the antistatic hard coat layer, and the distance between the conductive metal oxide particles becomes large. . For this reason, the electrically conductive path formed by contacting electroconductive metal oxide particle is hard to be formed, and there exists a problem that antistatic property is inferior.

In view of this, in the case of using single conductive metal oxide particles, the amount of the conductive metal oxide particles added is increased so that, for example, the conductive metal oxide particles are almost the same as the amount of the binder component in the antistatic hard coat layer composition. By adding so as to agglomerate and aggregating electroconductive metal oxide particle, a conductive path is formed and antistatic property is acquired.

However, when the addition amount of electroconductive metal oxide particle is made large, since there is much quantity of electroconductive metal oxide particle, there exists a problem that haze becomes high and transparency falls. In addition, since the amount of the conductive metal oxide particles is large, some of the conductive metal oxide particles sink, and the conductive metal oxide particles are arranged at the interface between the antistatic hard coat layer and the light transmissive substrate. For this reason, there exists a problem that the refractive index difference of an antistatic hardcoat layer and a transparent base material changes rapidly in the vicinity of these interfaces, and generation | occurrence | production of an interference fringe occurs.

Moreover, when the addition amount of electroconductive metal oxide particle is made large, the adhesiveness of a light transmissive base material and an antistatic hard coat layer may deteriorate. Moreover, when forming another layer on an antistatic hardcoat layer, the adhesiveness of an antistatic hardcoat layer and another layer may worsen.

In addition, Patent Document 2 (Japanese Patent Laid-Open No. 2006-126808) discloses that an antistatic layer is formed separately from the hard coat layer, and that cracking occurs in the antistatic layer. Patent Document 2 prevents interference fringes at the interface between the antistatic layer and the light transmissive substrate by causing cracks in the antistatic layer. However, since the antistatic layer is formed separately, a new interface is generated between the antistatic layer and the hard coat layer. It discards (refer FIG. 3 and FIG. 4 of patent document 2). Therefore, although generation | occurrence | production of interference fringes may be suppressed to some extent by generating a crack in an antistatic layer, it is insufficient from a viewpoint of suppressing generation | occurrence | production of interference fringes.

Japanese Patent Laid-Open No. 2006-130667 Japanese Patent Laid-Open No. 2006-126808

The present invention has been made to solve the above problems. That is, while the excellent antistatic property can be obtained, the fall of the transparency of an antistatic hard coat layer can be suppressed, the generation | occurrence | production of an interference fringe can be fully suppressed, and the manufacturing method of the optical film excellent in adhesiveness, and such optical It aims at providing the film, a polarizing plate, and the image display apparatus provided with this.

According to one aspect of the present invention, a weight average molecular weight having a chain metal oxide particle composed of two or more conductive metal oxide particles chained to the surface of a light transmissive substrate, a photopolymerizable monomer, and six or more photopolymerizable functional groups is present. Charging comprising at least one of a urethane (meth) acrylate having 1000 or more and a polymer (meth) acrylate having a weight average molecular weight of 10 or more having 10 or more photopolymerizable functional groups, and a permeable solvent having a permeability to the light transmissive substrate. The photocurable resin composition for the anti-hard coat layer is applied and dried to form a mixed layer in which the main component of the light transmissive substrate and the photopolymerizable monomer are mixed on the light transmissive substrate, and the chain metal oxide on the mixed layer. Particles, the photopolymerizable monomer and the urethane (meth) acrylate And a step of forming a chain metal oxide particle-containing layer containing at least one of the polymer (meth) acrylates, and curing the mixed layer and the chain metal oxide particle-containing layer by light irradiation to form a cured product of the mixed layer. And a step of forming an antistatic hard coat layer comprising a hard coat layer and a cured product of the chain metal oxide particle-containing layer and a second hard coat layer formed on the first hard coat layer. Content of the said chain metal oxide particle with respect to the total solid of a chemical conversion resin composition is 2-20 mass%, The manufacturing method of the optical film is provided.

According to another aspect of the present invention, there is provided an optical film having a light transmissive substrate and an antistatic hard coat layer formed on the light transmissive substrate, wherein the antistatic hard coat layer is a first hard coat layer formed on the light transmissive substrate. And a second hard coat layer formed on the first hard coat layer, wherein the first hard coat layer includes a main component of the light-transmissive substrate and a first binder resin, and the second hard coat layer includes: A weight average molecular weight comprising a chain metal oxide particle composed of two or more conductive metal oxide particles connected in a chain and a second binder resin, wherein the second binder resin has a photopolymerizable monomer and 6 or more photopolymerizable functional groups at 1000 Polymer (meth) acrylate whose weight average molecular weight which has ten or more urethane (meth) acrylates and photopolymerizable functional groups is 10000 or more At least one of the polymers, wherein the refractive index of the first hard coat layer is gradually changed from the second hard coat layer side toward the light transmissive substrate side to approach the refractive index of the light transmissive substrate, An optical film is provided wherein an interface does not exist between the light transmissive substrate and the first hard coat layer and between the first hard coat layer and the second hard coat layer.

According to another aspect of the present invention, there is provided a polarizing element formed on the surface opposite to the surface on which the optical film and the first hard coat layer in the light transmissive substrate of the optical film are formed. A polarizing plate is provided.

According to another aspect of the present invention, there is provided an image display device comprising the optical film or the polarizing plate.

According to the manufacturing method of the optical film of 1 aspect of this invention, since chain metal oxide particle is used as an antistatic agent, content of chain metal oxide particle is 2-20 with respect to the total solid of the photocurable resin composition for antistatic hard coat layers. Even in a small amount of mass%, excellent antistatic property can be obtained. Moreover, since content of a chain metal oxide particle is a small quantity of 2-20 mass% with respect to the total solid of the photocurable resin composition for antistatic hard coat layers, the fall of the transparency of an antistatic hard coat layer can be suppressed. In addition, since the chain metal oxide particles have a higher bulk density than the single conductive metal oxide particles, the chain metal oxide particles are difficult to sink, and even if they sink, the interface between the first hard coat layer and the second hard coat layer is caused by steric hindrance. Since it is not arrange | positioned in the vicinity, it can suppress that the refractive index difference changes abruptly in the vicinity of the interface of a 1st hard-coat layer and a 2nd hard-coat layer. According to this manufacturing method, not only the interface between the first hard coat layer and the second hard coat layer, but also the interface between the light transmissive substrate and the first hard coat layer does not exist, and the refractive index of the first hard coat layer is The antistatic hard coat layer can be formed so as to gradually approach the refractive index of the light transmissive substrate from the second hard coat layer side toward the light transmissive substrate side. Thereby, generation | occurrence | production of an interference fringe can fully be suppressed. Furthermore, since the antistatic hard coat layer which does not exist the interface between a transparent base material and a 1st hard-coat layer, and also does not exist the interface between a 1st hard-coat layer and a 2nd hard-coat layer can be formed, adhesiveness Can improve. Furthermore, the polymer whose weight average molecular weight which has ten or more urethane (meth) acrylates and 1000 photopolymerizable functional groups which have a weight average molecular weight which has 6 or more photopolymerizable functional groups in the photocurable resin composition for antistatic hard coat layers is 10000 or more ( Since at least one of the meth) acrylates is included, the hardness of the antistatic hard coat layer can be further improved.

Moreover, according to the optical film, the polarizing plate, and the image display apparatus of the other aspect of this invention, since the 2nd hard-coat layer contains the chain metal oxide particle as an antistatic agent, it can obtain the outstanding antistatic property and antistatic hard The fall of the transparency of a coat layer can be suppressed. Further, since the chain metal oxide particles have a higher bulk density than the single conductive metal oxide particles, the chain metal oxide particles are not arranged near the interface between the first hard coat layer and the second hard coat layer. It can suppress that the refractive index difference of a 2nd hard-coat layer changes rapidly in the vicinity of these interfaces. In addition, not only the interface between the first hard coat layer and the second hard coat layer, but also the interface between the light transmissive substrate and the first hard coat layer does not exist, and the refractive index of the first hard coat layer is the second hard coat layer side. From the side toward the light-transmissive substrate side, the film is gradually changed to approach the refractive index of the light-transmissive substrate. Thereby, generation | occurrence | production of an interference fringe can fully be suppressed. In addition, since there is no interface between the light transmissive substrate and the first hard coat layer, and there is no interface between the first hard coat layer and the second hard coat layer, the adhesion is excellent. A polymer having a weight average molecular weight of 10000 or more, in which the second binder resin has 10 or more urethane (meth) acrylates having a photopolymerizable monomer and 6 or more photopolymerizable functional groups and a urethane (meth) acrylate having 1000 or more and a photopolymerizable functional group ( Since the polymer of at least any one of meth) acrylates is included, hardness is also excellent.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows typically the manufacturing process of the optical film which concerns on embodiment.
FIG. 2 is a diagram schematically showing a manufacturing process of an optical film according to the embodiment. FIG.
3 is a diagram schematically illustrating a manufacturing process of an optical film according to the embodiment.
4 is a schematic configuration diagram of a polarizing plate according to an embodiment.
5 is a schematic configuration diagram of an image display device according to an embodiment.
The cross-sectional photograph of the optical film which concerns on Example 1 image | photographed using the scanning transmission electron microscope function of a scanning electron microscope.
The cross-sectional photograph of the surface vicinity of the optical film which concerns on Example 1 image | photographed using the scanning transmission electron microscope function of a scanning electron microscope.
FIG. 8 is an enlarged cross-sectional photograph of the vicinity of the surface of the optical film shown in FIG. 7. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing method etc. of the optical film which concern on embodiment of this invention are demonstrated, referring drawings. 1-3 is a figure which shows typically the manufacturing process of the optical film which concerns on this embodiment.

<< manufacturing method of optical film >>

First, as shown in FIG. 1A, the light transmissive substrate 1 is prepared. The light transmissive substrate 1 is not particularly limited as long as it has light transmittance. Specifically, the light-transmissive base material 1 includes a cellulose acylate, a cycloolefin polymer, a polycarbonate or an acrylate polymer.

As cellulose acylate, a cellulose triacetate and a cellulose diacetate are mentioned, for example. As a cycloolefin polymer, polymers, such as a norbornene-type monomer and a monocyclic cycloolefin monomer, are mentioned, for example.

Examples of the polycarbonate include aliphatic polycarbonates such as aromatic polycarbonates based on bisphenols (such as bisphenol A) and diethylene glycol bisaryl carbonate.

Examples of the acrylate polymers include methyl poly (meth) acrylate, ethyl poly (meth) acrylate, methyl (meth) acrylate-butyl methacrylate and the like.

Among these, cellulose acylate is preferable at the point which is excellent in light transmittance, and triacetyl cellulose is preferable among cellulose acylate. A triacetyl cellulose film (TAC film) is a light transmissive base material which can make an average light transmittance 50% or more in visible region 380-780 nm. The average light transmittance of the TAC film is more preferably 70% or more and 85% or more.

Moreover, as triacetyl cellulose, in addition to pure triacetyl cellulose, a component other than acetic acid may also be used together as a fatty acid which forms cellulose and ester like cellulose acetate propionate and cellulose acetate butyrate. Moreover, various additives, such as other cellulose lower fatty acid esters, such as diacetyl cellulose, or a plasticizer, an ultraviolet absorber, and a sliding agent, may be added to these triacetyl cellulose as needed.

After preparing the light transmissive substrate 1, the photocurable resin composition for an antistatic hard coat layer is applied to the surface of the light transmissive substrate 1 as shown in FIG. 1B (hereinafter, for simplicity, Photocurable resin composition for an antistatic hard coat layer "is referred to as" composition for an antistatic hard coat layer ". As a method of apply | coating the composition for antistatic hard coat layers, well-known coating methods, such as a spin coat method, an immersion method, a spray method, the slide coat method, the bar coat method, the roll coating method, the gravure coating method, the die coating method, are mentioned. .

<Composition for antistatic hard coat layer>

The composition for antistatic hard coat layer is urethane (meth) which has a weight average molecular weight of 1000 or more which has a photopolymerizable monomer which becomes a part of binder resin or binder resin after hardening by chain metal oxide particle | grains, light irradiation, and 6 or more photopolymerizable functional groups. At least one of the polymer (meth) acrylate whose weight average molecular weight which has 10 or more of an acrylate and a photopolymerizable functional group is 10000 or more, and a permeable solvent are included. In addition, in this invention, "(meth) acrylate" means at least any one of "acrylate" and "methacrylate."

(Chain metal oxide particles)

The chain metal oxide particles have a form in which two or more conductive metal oxide particles are chained together. Here, the "metal oxide" in the present invention is a concept including the metal oxide doped with different metals. In addition, "chain" is a concept including both linear and branched chains.

The chain metal oxide particles are bonded to the conductive metal oxide particles, unlike the primary particles of the conductive metal oxide particles being simply aggregated by interparticle attraction or the like. These chain metal oxide particles may be linear, may be linear, and may be curved.

The chain metal oxide particles may have a form in which two or more conductive metal oxide particles are connected in a chain shape, but the conductive metal oxide particles are preferably connected in 2 to 50 chains, more preferably 3 to 30 pieces. desirable. The number of the connection of the conductive metal oxide particles in the above range is because if the conductive metal oxide particles that are not connected, i.e., the conductive metal oxide particles alone, the surface resistance value may not be effectively lowered, and the number of connections is 50. It is because there exists a possibility that the light transmittance of an antistatic hard coat layer may fall, and a haze may rise when exceeding the number.

It is preferable that it is 1-100 nm, and, as for the average primary particle diameter of electroconductive metal oxide particle, it is more preferable that it is 5-80 nm. What set the average primary particle diameter of electroconductive metal oxide particle in the said range is that when an average primary particle diameter of electroconductive metal oxide particle exceeds 100 nm, it becomes difficult to connect electroconductive metal oxide particle, and even if it was possible, for example, a conductive metal This is because it is difficult to effectively lower the surface resistance value because the contact point of the oxide particles is reduced. Moreover, when the average primary particle diameter of electroconductive metal oxide particle exceeds 100 nm, the absorption of light by electroconductive metal oxide particle will become large, the light transmittance of an antistatic hard coat layer will fall, or the haze value of an antistatic hard coat layer will become This is because there is a risk of increase. In addition, when the average particle diameter of electroconductive metal oxide particle is less than 1 nm, since grain boundary resistance increases rapidly, there exists a possibility that surface resistance value may not be reduced effectively.

Said "average primary particle diameter" means the value measured using the Microtrac particle size analyzer made by Nikkiso Corporation in the composition, and in a cured film, the transmission electron microscope of the cross section of the cured film ( TEM) photograph and a scanning transmission electron microscope (STEM) photograph shall mean the average value of ten electroconductive metal oxide particle | grains. Specifically, for example, 10 conductive metal oxide particles are selected in a cross-sectional photograph taken at a magnification (for example, 200,000 times) capable of confirming one size of the conductive metal oxide particles as shown in FIG. By measuring the diameter of the selected electroconductive metal oxide particle, respectively, and obtaining the average value, the average primary particle diameter of the electroconductive metal oxide particle in a cured film can be calculated | required.

It is preferable that it is 10-500 nm, and, as for the average length of the chain metal oxide particle in the cured film at the time of cross-sectional observation of a cured film, it is more preferable that it is 10-500 nm. The average length of the chain metal oxide particles is in the above range because the contact resistance may increase when the average length is less than 10 nm, and the surface resistance value may not be effectively lowered. This is because the transparency of the coat layer may not be obtained. "Average length of the linear metal oxide particle in a hardened film" means ten average values of the linear electroconductive metal oxide particle observed with the transmission electron microscope (TEM) photograph and the scanning transmission electron microscope (STEM) photograph of the cross section of a cured film. Shall be. Specifically, in the cross-sectional photograph photographed by the magnification (for example, 200,000 times or more) which can confirm one size of the chain | strand-shaped conductive metal oxide particle with which two or more conductive metal oxide particles are connected, for example, a chain-conductive metal By selecting ten oxide particles and measuring the length of the longest part of the selected chain conductive metal oxide particle, respectively, and calculating the average value thereof, the average length of the chain conductive metal oxide particles in the cured film can be obtained. In addition, although the linear metal oxide particle exists in various shapes, such as a curved shape, in the length measurement, it can measure by putting a thing in a thread shape on a photograph, and drawing along various shapes.

The conductive metal oxide particles are not particularly limited as long as they are particles of conductive metal oxides. Examples of the conductive metal oxide particles include antimony-doped tin oxide (abbreviated ATO), phosphorus-doped tin oxide (abbreviated PTO), and tin-doped indium oxide (abbreviated ITO). ), Aluminum dope zinc oxide (abbreviated as AZO), gallium dope zinc oxide (abbreviated as GZO), ZnO, CeO ₂ , Sb ₂ O ₅ , SnO ₂ , In ₂ O _3, and Al ₂ O ₃ .

Content of the chain metal oxide particle with respect to the total solid of the composition for antistatic hard coat layers needs to be 2-20 mass%. This range is preferable because the content of the chain metal oxide particles may be less than 2%, so that the target antistatic performance may not be expressed. When the content is more than 20%, the antistatic performance becomes a limit and antistatic It is because there exists a possibility that transparency of a hard coat layer may fall, haze value may rise, and also the storage stability of the composition for antistatic hard coat layers may deteriorate. In this invention, when a polymerization initiator is contained in the composition for antistatic hard coat layers, a polymerization initiator shall not be converted as solid content.

Chain metal oxide particles can be obtained as follows. First, the alcohol solution containing metal salt or metal alkoxide in the density | concentration of 0.1-5 mass% is heated and hydrolyzed. At this time, hot water or alkali is added as necessary. By such hydrolysis, a gel dispersion of a metal hydroxide having a primary particle diameter of 1 to 100 nm is prepared. Subsequently, the gel dispersion is separated by filtration and washed, and then fired at a temperature of 200 to 800 ° C in air to produce conductive metal oxide particles.

Subsequently, this powder is dispersed in at least one of acidic or alkaline water and an alcohol solvent to obtain a dispersion having a concentration of 10 to 50% by mass, and mechanical dispersion treatment of the dispersion is carried out in the presence of an organic stabilizer as necessary. Specific examples of the organic stabilizer include polyvalent carboxylic acids such as gelatin, polyvinyl alcohol, polyvinylpyrrolidone, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid and citric acid. And salts thereof, heterocyclic compounds or mixtures thereof. By this mechanical dispersion treatment, the resulting gel is peptized to obtain a sol in which the chain metal oxide particles are dispersed. Examples of such mechanical dispersion treatment include a sand mill method and an impact dispersion method, and in particular, an impact dispersion method is preferably used.

The chain metal oxide particles thus obtained are usually taken out from the dispersion after production by a method such as centrifugation and washed with an acid or the like as necessary. In addition, the dispersion liquid containing the obtained chain metal oxide particle can also be used as a coating liquid as it is.

As a commercial item of a chain metal oxide particle, ELCOM-V3560, DP1197, DP1203, DP1204, DP1207, DP1208 made by Nikki Shokubai Kasei Co., Ltd. is mentioned, for example.

(Photopolymerizable monomer)

The photopolymerizable monomer has at least one photopolymerizable functional group. The "photopolymerizable functional group" in the present invention is a functional group capable of polymerization reaction by light irradiation to form crosslinks between molecules. As a photopolymerizable functional group, ethylenic double bonds, such as a (meth) acryloyl group, a vinyl group, an allyl group, are mentioned, for example. In addition, a "(meth) acryloyl group" means at least any one of a "acryloyl group" and a "methacryloyl group." In addition, the "light" in the present invention includes not only electromagnetic waves of wavelengths in the visible region and wavelengths in the invisible region such as ultraviolet rays, but also radiations or ionizing radiations collectively referred to as particle beams such as electron beams and electromagnetic waves and particle beams. Shall be. As a photopolymerizable monomer, the polyfunctional monomer etc. which have a 2 or more photopolymerizable functional group whose weight average molecular weight is less than 1000 are mentioned.

As a bifunctional monomer, 1, 6- hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, Tripropylene glycol di (meth) acrylate, polyethylene glycol 400 di (meth) acrylate, hydroxy pivaric acid ester neopentyl glycol di (meth) acrylate, bisphenol AEO modified di (meth) acrylate, isocyanuric acid (Meth) acrylate, polyester di (meth) acrylate, bisphenol A di (meth) acrylate, adamantyldi (meth) acrylate, isoboroyldi (meth) acrylate, dicyclopentanedi (meth) Acrylate, tricyclodecane di (meth) acrylate, and the like. These may be modified with ethylene oxide, propylene oxide, caprolactone and the like.

As a trifunctional or more than trifunctional monomer, the trifunctional or more (meth) acryloyl monomer etc. which are obtained by making (meth) acrylic acid or its derivative (s) react with ethylene glycol, glycerin, pentaerythritol, an epoxy resin, etc. can be used, for example, trimethyl All propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate , Tripentaerythritol octa (meth) acrylate, tetrapentaerythritol deca (meth) acrylate, isocyanuric acid tri (meth) acrylate, trimethylolpropane EO modified tri (meth) acrylate, dimethylolpropane tetra (Meth) acrylate etc. are mentioned.

Pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol from the viewpoint of obtaining an antistatic hard coat layer having a high hardness among these. Pentaacrylate (DPPA) and the like are preferred.

It is preferable that content of the photopolymerizable monomer with respect to the total solid of the composition for antistatic hard coat layers is 10-70 mass%. This range is preferable because if the content of the photopolymerizable monomer is less than 10% by mass, the desired hardness may not be obtained as the hardness of the optical laminate, and interference fringes may also occur, and if it exceeds 70% by mass, In order to improve the hardness, when a polyfunctional photopolymerizable monomer is used, there is a risk of curling, and thermal damage is caused to the optical laminate by the heat of reaction at the time of curing (in the crosslinking reaction). This is because there is a risk of appearance deteriorating.

(Urethane (meth) acrylate and polymer (meth) acrylate)

Urethane (meth) acrylate has 6 or more photopolymerizable functional groups (for example, (meth) acryloyl group) (6 functional), and a weight average molecular weight is 1000 or more. Although the weight average molecular weight of urethane (meth) acrylate should just be 1000 or more, For example, what is 1000 or more and 10000 or less can be used as a weight average molecular weight. "Weight average molecular weight" is a value obtained by melt | dissolving in solvents, such as tetrahydrofuran (THF), and polystyrene conversion by a conventionally well-known gel permeation chromatography (GPC) method.

The polymer (meth) acrylate has 10 or more photopolymerizable functional groups (for example, (meth) acryloyl groups) (10 functional), and a weight average molecular weight is 10000 or more. Although the weight average molecular weight of a polymer (meth) acrylate should just be 10000 or more, about 10000-80000 are preferable as a weight average molecular weight, and about 10000-400000 are more preferable. When a weight average molecular weight exceeds 80000, since a viscosity is high, application | coating suitability falls and there exists a possibility that the external appearance of the optical laminated body obtained may deteriorate.

By including the urethane (meth) acrylate and / or polymer (meth) acrylate in the composition for the antistatic hard coat layer, the hardness of the antistatic hard coat layer can be increased and the degree of penetration of the photopolymerizable monomer can be adjusted. have. Moreover, when urethane (meth) acrylate is included in the composition for antistatic hard coat layers, adhesiveness with the other layer (for example, low refractive index layer) formed on an antistatic hard coat layer can be improved.

It is preferable that it is 150 or more and 500 or less, and, as for the functional group equivalent of the said urethane (meth) acrylate, and the functional group equivalent of the said polymer (meth) acrylate, it is more preferable that it is 160 or more and 400 or less. Here, "functional group equivalent" means the weight average molecular weight per one photopolymerizable functional group. For example, in the case of the urethane (meth) acrylate whose weight average molecular weight which has 6 or more photopolymerizable functional groups is 1000, a functional group equivalent is computed as 1000/6 and becomes about 167. In the above-mentioned, the functional group equivalent of 150 or more and 500 or less is preferable because curling is hard to generate | occur | produce if it is 150 or more, and if it is 500 or less, desired pencil hardness can be ensured.

In addition, since urethane (meth) acrylate can make functional group equivalent small and weight average molecular weight small compared with polymer (meth) acrylate, the viscosity of the composition for antistatic hard coat layers is kept low, and it is favorable. Application ability can be obtained. From this viewpoint, urethane (meth) acrylate is more preferable than polymer (meth) acrylate.

It is preferable that content of a urethane (meth) acrylate and / or a polymer (meth) acrylate with respect to the total solid of the composition for antistatic hard coat layers is 10-70 mass%. Here, when both a urethane (meth) acrylate and a polymer (meth) acrylate are contained in the composition for antistatic hard coat layers, the said content is content which added the urethane (meth) acrylate and the polymer (meth) acrylate together. I mean it. It is preferable that this range is such that the content of the urethane (meth) acrylate and / or the polymer (meth) acrylate is less than 10% by mass, in particular, the adhesion to the layer (low refractive index layer) on the antistatic hard coat layer is deteriorated. The SW resistance may deteriorate. In addition, there is a fear that excellent hardness cannot be obtained. Moreover, when it exceeds 70 mass%, there exists a possibility that interference fringes may arise because the ratio of a photopolymerizable monomer reduces.

Although the said urethane (meth) acrylate can use the compound by reaction of the isocyanate compound obtained by making the following polyol and diisocyanate react, and the (meth) acrylate monomer which has a hydroxyl group, It is not limited to the combination.

Examples of the polyols include polyester polyols, polyether polyols, and polycarbonate diols. The manufacturing method of polyester polyol is not specifically limited, It can manufacture by a well-known manufacturing method. For example, it is obtained by carrying out polycondensation reaction of diol, dicarboxylic acid, or dicarboxylic acid chloride, or esterification of a diol or dicarboxylic acid, and transesterification.

Examples of the diol include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, and the like. As dicarboxylic acid, adipic acid, succinic acid, glutaric acid, pimelic acid, sebacic acid, azelaic acid, maleic acid, terephthalic acid, isophthalic acid, phthalic acid, etc. are mentioned.

Examples of the polyether polyols include polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide random copolymerization, and the like.

Examples of the polycarbonate diol include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene Glycol, 2-ethyl-1, 3-hexanediol, 1,5-pentanediol, 3-methyl-1, 5-pentanediol, 1,4-cyclohexanediol, polyoxyethylene glycol, and the like.

As diisocyanate, linear or cyclic aliphatic diisocyanate or aromatic diisocyanate is used. Examples of the linear or cyclic aliphatic diisocyanate include hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexyl methane diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated xylylene diisocyanate. As aromatic diisocyanate, tolylene diisocyanate, xylylene diisocyanate, etc. are mentioned.

Examples of the (meth) acrylate monomer having a hydroxyl group include ditrimethylol propane triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, and the like.

A commercial item may be used for the said urethane acrylate, As a commercial item, for example, Nippon Kose Chemical Co., Ltd. UV1700B (molecular weight 2000, 10 functional), UV6300B (molecular weight 3700, 7 functional) and UV7640B (molecular weight 1500) , 7-function), DPHA40H (molecular weight 7000, 8-functionality), UX5000 (molecular weight 1000, 5-functional) and UX5001T (molecular weight 6200, 8-functional) made by Nippon Kayaku Kabushiki Kaisha Co., Ltd. Molecular weight 5000, 15 functional), UN904 (molecular weight 4900, 10 functional), UN3320HC (molecular weight 1500, 6 functional) and UN3320HA (molecular weight 1500, 6 functional), BS577 (molecular weight 1000, made by Arakawa Kagaku Kogyo Co., Ltd.) 6-functional), and U15H (15-functional) and U6H (6-functional) by Shin-Nakamura Kagaku Kogyo Co., Ltd., etc. are mentioned.

As said polymer (meth) acrylate, urethane (meth) acrylate, isocyanurate (meth) acrylate, polyester urethane (meth) acrylate, epoxy (meth) acrylate, etc. are mentioned.

As a commercial item of an epoxy acrylate, the beam set 371 made from Arakawa Chemical Industries, Ltd. is mentioned.

(Invasive solvent)

A "permeable solvent" is a solvent which has high permeability with respect to a light transmissive base material, and melts or swells a light transmissive base material. By using the permeable solvent, not only the permeable solvent but also the photopolymerizable monomer can permeate the light-transmissive substrate.

As a permeable solvent, For example, ketones, such as acetone, methyl ethyl ketone (MEK), cyclohexanone, methyl isobutyl ketone, diacetone alcohol, cycloheptanone, diethyl ketone; Esters such as methyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate and ethyl lactate; Nitrogen-containing compounds such as nitromethane, acetonitrile, N-methylpyrrolidone and N, N-dimethylformamide; Glycols such as methyl glycol and methyl glycol acetate; Ethers such as tetrahydrofuran, 1,4-dioxane, dioxolane and diisopropyl ether; Halogenated hydrocarbons such as methylene chloride, chloroform and tetrachloroethane; Glycol ethers such as methyl cellosolve, ethyl cellosolve, butyl cellosolve and cellosolve acetate; In addition, dimethyl sulfoxide and propylene carbonate are mentioned. Moreover, a mixture thereof may be sufficient. Among these, it is preferable that it is at least 1 sort (s) chosen from the group which consists of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and methyl ethyl ketone.

It is preferable that the addition amount of a permeable solvent is 50-500 mass parts with respect to 100 mass parts of total solids of the composition for antistatic hard coat layers. This range is preferable because the permeable solvent does not sufficiently penetrate into the light transmissive substrate if the amount of the permeable solvent is less than 50 parts by mass, and there is a fear that interference fringes may occur. This is because there is a possibility of dissolving or swelling more than necessary, and the desired hardness may not be obtained as the optical film.

(Other ingredients)

In addition, you may add a polymerization initiator, a dispersing agent, a releasing agent, microparticles | fine-particles, an anti-glare, etc. to the composition for antistatic hard coat layers as needed.

(Polymerization initiator)

A polymerization initiator is a component which decomposes | disassembles by light irradiation, generate | occur | produces a radical, and starts or advances superposition | polymerization of a photopolymerizable monomer.

The polymerization initiator is not particularly limited as long as the polymerization initiator can release a substance that initiates radical polymerization by light irradiation. Examples of the polymerization initiator include acetophenones, benzophenones, ketals, anthraquinones, disulfide compounds, thiuram compounds, and fluoroamine compounds. More specifically, 1-hydroxy cyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino propane- 1-one, benzyl dimethyl ketone, 1- (4 -Dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2- Hydroxy-2-methylpropan-1-one, benzophenone and the like can be exemplified. Among these, 1-hydroxy cyclohexyl phenyl ketone and 2-methyl-1- [4- (methylthio) phenyl] -2- morpholino propane- 1-one are polymerization reactions by light irradiation even if it is a small quantity. It is preferable because it can start or promote. The polymerization initiator can be used alone or in combination of any of the above.

As a commercial item of a polymerization initiator, Irgacure (trademark) 184 (1-hydroxy cyclohexylphenyl ketone) by BASF Corporation, Irgacure (registered trademark) 907 (2-methyl-1), for example. -(4-methylthiophenyl) -2-morpholinopropan-1-one) Irgacure (registered trademark) 127 (2-hydroxy-1 [4- [4- (2-hydroxy-2- Methyl-propionyl) -benzyl] phenyl] -2-methyl-propane-l-one), lucilin (registered trademark) TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), etc. are mentioned. have.

(Release agent)

A lubricating agent (anti blocking agent) is a component which prevents adhesion at the time of superimposing an antistatic hard coat layer and a transparent base material, such as making into a roll state. As the releasing agent, a conventionally known releasing agent can be used, for example, fine particles of inorganic compounds such as silica described in Japanese Patent Laid-Open No. 2004-284126 having an average primary particle size of 100 to 1000 nm, high density polyethylene, polystyrene, Microparticles | fine-particles of organic compounds, such as polystyrene acryl, can be used. It is preferable that content of a lubricating agent is 0.1-5 mass% with respect to the total mass of the total solid of the composition for antistatic hard coat layers.

(Hardening fine particles)

Hardness provision microparticles | fine-particles are components which improve the hardness of an antistatic hard coat layer. As microparticles | fine-particles, a well-known thing which can be used for an antistatic hard coat layer may be employ | adopted suitably according to a required performance.

It is preferable that the average particle diameter of hardness provision microparticles | fine-particles is 1-100 nm from a transparency viewpoint of a hard-coat layer. It is easy to provide hardness, being this range, maintaining transparency of a hard-coat layer. The fine particles may be aggregated particles, and in the case of aggregated particles, the secondary particle diameter may be within the above range.

There is no restriction | limiting in particular in the addition amount in the composition for antistatic hard coat layers of hardness provision microparticles | fine-particles, what is necessary is just to set suitably in consideration of hardness, etc. It is preferable that it is 0-40 mass% with respect to the total solid of the composition for antistatic hard coat layers from the viewpoint of the hardness improvement of an antistatic hard coat layer, and, as for the addition amount of microparticles | fine-particles, it is more preferable that it is 10-30 mass%. When it exceeds 40 mass%, there exists a possibility that antistatic performance may not express.

The fine particles may be inorganic fine particles or organic fine particles, but are preferably inorganic fine particles from the viewpoint of hardness. Examples of the inorganic fine particles include silica (SiO ₂ ) fine particles, alumina fine particles, and the like.

The silica fine particles may be surface treated. Moreover, as silica fine particles, what has an ultraviolet reactor on the surface from the point of hardness is preferable. The shape of the silica fine particles may be spherical, amorphous, mold release, or chain. As a commercial item of a silica fine particle, Nissan Chemical Industries, Ltd. IPA-ST, IPASTMS, IPAST (L), etc. are mentioned.

Since alumina is a material having a high Mohs hardness, when alumina fine particles are used as the inorganic fine particles, the hardness can be further improved. The alumina fine particles may be subjected to surface treatment similarly to silica fine particles.

Examples of the organic fine particles include plastic beads. Specific examples of the plastic beads include polystyrene beads, melamine resin beads, acrylic beads, acrylic styrene beads, silicone beads, benzoguanamine beads, benzoguanamine-formaldehyde condensation beads, polycarbonate beads, polyethylene beads, and the like. have. It is preferable that the said plastic beads have a hydrophobic group on the surface, For example, styrene beads can be mentioned.

(Antiglare)

The antiglare agent is a component for imparting antiglare function to the hard coat layer. As an anti-glare agent, microparticles | fine-particles are mentioned, The shape of microparticles | fine-particles may be a spherical shape, an ellipse shape, etc., Preferably, a spherical shape is mentioned. Moreover, although an inorganic type and organic type are mentioned, microparticles | fine-particles are preferably formed with an organic type material. Microparticles | fine-particles exhibit anti-glare property, Preferably it is good that it is transparency. Specific examples of the fine particles include plastic beads, and more preferably those having transparency. Specific examples of the plastic beads include styrene beads (refractive index 1.59), melamine beads (refractive index 1.67), acrylic beads (refractive index 1.49), acrylic styrene beads (refractive index 1.54), polycarbonate beads, polyethylene beads, and the like.

When the composition 2 for antistatic hard coat layers is apply | coated to the surface of the light transmissive base material 1, some permeable solvent and some photopolymerizable monomers permeate | transmit on the upper part of the light transmissive base material 1. On the other hand, the weight average molecular weight which has ten or more urethane (meth) acrylates and / or photopolymerizable functional groups which have a weight average molecular weight which has 6 or more of linear metal oxide particle | grains and 6 or more photopolymerizable functional groups in the composition for hard-coat layers has Since the polymer (meth) acrylate of 10000 or more is large in size, it does not penetrate into the transparent base material 1, but remains on the transparent base material 1.

Subsequently, for example, drying at 30 to 100 ° C. for 15 seconds or more to remove the permeable solvent, as shown in FIG. 2A, the main component of the light transmissive substrate 2 on top of the light transmissive substrate 1 And a mixed layer 3 in which the photopolymerizable monomer is mixed with the photopolymerizable monomer, and the photopolymerizable monomer remaining on the light transmissive substrate 1 without penetrating the chain metal oxide particles and the transparent substrate 1 on the mixed layer 3; The chain metal oxide particle containing layer 4 containing urethane (meth) acrylate and / or the said polymer (meth) acrylate is formed. The light-transmissive base material 1A after forming the mixed layer 3 is thinner than the light-transmissive base material 1 by the thickness of the mixed layer 3. In addition, the "main component of a transparent base material" in this invention shows the component with the highest content rate among the structural components of a transparent base material.

Thereafter, as shown in FIG. 2B, the mixed layer 3 and the chain metal oxide particle-containing layer 4 are irradiated with light such as ultraviolet rays to polymerize the photopolymerizable monomer included in the mixed layer 3. By curing the mixed layer 3 and polymerizing the photopolymerizable monomer and urethane (meth) acrylate and / or polymer (meth) acrylate contained in the chain metal oxide particle-containing layer 4, the chain metal oxide particle-containing layer ( 4) is cured. Thereby, the antistatic hard coat layer 7 which consists of the 1st hard-coat layer 5 which is the hardened | cured material of the mixed layer 3, and the 2nd hard-coat layer 6 which is the hardened | cured material of the chain metal oxide particle containing layer 4 is Is formed. When ultraviolet rays are used as the light, ultraviolet rays emitted from an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, or the like can be used.

The 1st hard-coat layer 5 contains the main component of 1 A of transparent base materials, and the 1st binder resin containing the polymer of a photopolymerization monomer. In addition, the second hard coat layer 6 contains chain metal oxide particles and a second binder resin. The second binder resin includes a photopolymerizable monomer and a polymer of the urethane (meth) acrylate and / or the polymer (meth) acrylate. The antistatic hard coat layer 7 has a hardness of "H" or more by the pencil hardness test specified in JISK5600-5-4 (1999).

After forming the antistatic hardcoat layer 7, as shown in FIG. 3, a low refractive index having a refractive index lower than that of the antistatic hardcoat layer 7 on the second hardcoat layer 6, as necessary. Form layer 8. Specifically, for example, the low refractive index layer 8 is a curable resin composition for a low refractive index layer (hereinafter referred to as "curable resin composition for a low refractive index layer" on the second hard coat layer 6 for the sake of simplicity. ”, And it can form by making it dry and harden | cure. Thereby, the optical film 10 shown in FIG. 3 is produced.

(Composition for Low Refractive Index Layer)

As a composition for low refractive index layers, the composition containing the component with low refractive index, such as a silica and magnesium fluoride, and a photopolymerizable monomer, a photopolymerizable oligomer, or a photopolymerizable polymer used as a binder resin after hardening, is mentioned, for example. Moreover, you may add a polymerization initiator etc. in the composition for low refractive index layers. As a photopolymerizable monomer, a photopolymerizable oligomer, or a photopolymerizable polymer, the thing similar to the photopolymerizable monomer etc. which were illustrated by the composition for antistatic hard coat layers can be used. In addition, you may use at least any one of a monomer, an oligomer, and a polymer of an organic fluorine compound. Since an organic fluorine compound is weak in hardness, it is preferable that it is an ultraviolet curable type.

In addition, the composition for forming the low refractive index layer may contain hollow particles such as hollow silica particles in order to reduce the refractive index of the low refractive index layer. The hollow particles refer to particles having an outer layer and surrounded by the outer layer with a porous structure or cavity. The porous structure or cavity contains air (refractive index: 1), and the refractive index of the low refractive index layer can be reduced by including hollow particles having a refractive index of 1.20 to 1.45 in the low refractive index layer. It is preferable that the average particle diameter of a hollow particle is 1-100 nm. As a hollow particle, what is used for a conventionally well-known low refractive index layer can be used, For example, the microparticle which has a space | gap as described in Unexamined-Japanese-Patent No. 2008-165040 is mentioned. What is necessary is just to select the film thickness of a low refractive index layer suitably according to the performance calculated | required, It is preferable that it is 80-120 nm.

<< optical film >>

The optical film which concerns on this embodiment is obtained by the said manufacturing method. That is, as shown in FIG. 3, the optical film 10 includes a light transmissive substrate 1A and an antistatic hard coat layer 7 formed on the light transmissive substrate 1A.

The antistatic hard coat layer 7 is formed on the light transmissive substrate 1A, the first hard coat layer 5 comprising the main component of the light transmissive substrate 1A and the first binder resin, and the first hard coat layer. (5) Consists of a second hard coat layer 6 formed of a second binder resin and a chain metal oxide particle composed of two or more conductive metal oxide particles connected in a chain and dispersed in the second binder resin. It is. In addition, although the optical film 10 shown in FIG. 3 further includes the low refractive index layer 8, the optical film 10 does not need to be provided with the low refractive index layer 8. FIG.

It is preferable that the thickness of the 1st hard-coat layer 5 is 0.5-10 micrometers. It is preferable that this range is that when the thickness of the first hard coat layer 5 is less than 0.5 µm, the adhesion with the light transmissive substrate may be deteriorated. The reason for this is that the curing failure may occur, the permeable solvent may remain in the light-transmitting substrate after drying, or cracks or curls may occur after curing.

It is preferable that the thickness of the 2nd hard-coat layer 6 is 1-10 micrometers. If the thickness of the second hard coat layer 6 is less than 1 µm, this range is preferable, and the hardness as the hard coat layer may be lowered. In addition, since the transparent substrate is swollen by the use of a permeable solvent, fine irregularities are formed on the surface of the transparent substrate, but if the thickness of the second hard coat layer is less than 1 µm, the haze slightly increases due to the irregularities. When the second hard coat layer is viewed from the inclination, the second hard coat layer may appear white. On the other hand, when it exceeds 10 micrometers, the light transmittance of a 2nd hard-coat layer falls, and there exists a possibility that curl and a crack may arise. Further, since the chain metal oxide particles have a high cost, there is a fear that the cost will increase.

The refractive index of the first hard coat layer 5 changes from the second hard coat layer 6 side toward the light transmissive substrate 1A side gradually to approach the refractive index of the light transmissive substrate 1A. Since this infiltrates the photopolymerizable monomer into the light transmissive substrate 1 from the surface side of the light transmissive substrate 1 as described above, the photopolymerizable monomer in the mixed layer 3 is the chain metal oxide particle layer of the mixed layer 3 ( It is considered to occur because it has a concentration gradient gradually decreasing from the 4) side toward the light-transmissive substrate 1A side.

Such a change in refractive index can be confirmed by observation using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM) of the cross section in the film thickness direction of the optical film.

There is no interface between the light transmissive substrate 1A and the first hard coat layer 5 and between the first hard coat layer 5 and the second hard coat layer 6. These interfaces mean the interface which can be visually recognized by observation using the transmission electron microscope (TEM) or the scanning transmission electron microscope (STEM) of the cross section of the film thickness direction of the optical film 10. FIG. Therefore, if these interfaces cannot be recognized by observation using TEM or STEM, it is determined that there is no interface. In addition, since TEM and STEM measure secondary electrons generated by electron beam irradiation, at the interface between the upper layer and the lower layer, when the material constituting the upper layer and the material constituting the lower layer are mixed in a gradient shape or the upper layer When the electron emission characteristic of the secondary electrons of the material which comprises the material and the material which comprises a lower layer is the same, even if an interface exists, the interface is not visually recognized by observation using TEM. The absence of these interfaces can also be confirmed by the absence of interference fringes. There is no layer interface without interference fringes. The interference fringe can be confirmed by attaching a black tape to the surface on the side opposite to the surface on which the first hard coat layer in the optically transparent substrate of the optical film is formed and observing under a three-wavelength fluorescent lamp.

From the viewpoint of obtaining excellent antistatic property, the surface resistance value of the optical film 10 is preferably 10 ¹² Ω / □ or less, more preferably 10 ¹¹ Ω / □ or less, further preferably 10 ¹⁰ Ω / □ or less. Do. In the case where the low refractive index layer 8 is not provided, even after the saponification process of the optical film or after wiping the surface with a solvent, the surface resistance value is preferably 10 ¹² Ω / □ or less, and preferably 10 ¹¹ Ω / □ or less. More preferably, it is more preferable that it is 10 <^10> ohm / square or less. A saponification process is performed by immersing an optical film for 15 second-5 minutes in 40-70 degreeC NaOH or KOH aqueous solution adjusted to 1.5-4.5 specification. As an apparatus which can be used for the measurement of a surface resistance value, the Hyrestar HT-210 by Mitsubishi Yuka Corporation.

From the viewpoint of obtaining excellent transparency, the total light transmittance of the optical film 10 is preferably 88% or more when the low refractive index layer 8 is not provided. Moreover, when providing the low refractive index layer 8, it is preferable that it is 90% or more, and it is more preferable that it is 92% or more. Moreover, it is preferable that it is 1.0% or less, and, as for the haze value of the optical film 10, from a viewpoint of obtaining the outstanding transparency, it is more preferable that it is 0.7% or less. Total light transmittance is measured according to JISK7361, and haze value is measured according to JISK7136. As an apparatus which can be used for the measurement of total light transmittance and a haze value, HM-150 by Murakami Color Technology Research Institute, etc. are mentioned. In addition, "transparency" can be evaluated by total light transmittance and a haze value.

From the viewpoint of preventing reflection of external light, the reflected Y value of the optical film 10 is preferably 2.0% or less, more preferably 1.5% or less, still more preferably 1.2% or less, further preferably 1.0% or less. It is more preferable that it is 0.7% or less. The reflected Y value is a value represented by the luminous reflectance calculated by soft (incorporated in the MCP3100 to be described later) which measures 5 ° specular reflectance in the wavelength range from 380 to 780 nm, and then converts it into brightness that is felt by the human eye. . In addition, when measuring 5 degree regular reflectance, in order to prevent the back surface reflection of the film which is an optical film, a black tape is stuck on the opposite side to a measurement film surface, and it measures. As an apparatus which can be used for the measurement of the reflection Y value, the MCP3100 by Shimadzu Corporation, Ltd., etc. are mentioned.

The steel wool abrasion resistance of the optical film 10 is free of scratches when the surface of the optical film 10 is rubbed 10 times at a speed of 100 mm / sec while applying a load of 100 g / cm 2 using a steel wool of # 0000. It is more preferable, and it is more preferable that there is no scratch when 10 reciprocating frictions are performed at the speed of 100 mm / sec, applying a load 300g / cm <2>.

<< polarizing plate >>

The optical film 10 can be embedded in a polarizing plate, for example, and can be used. 4 is a schematic configuration diagram of a polarizing plate incorporating an optical film according to the present embodiment. As shown in FIG. 4, the polarizing plate 20 includes an optical film 10 and a polarizing element 21. The polarizing element 21 is formed in the surface on the opposite side to the surface in which the 1st hard-coat layer 5 in 1 A of transparent substrates is formed.

As the polarizing element 21, for example, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymerized saponification film, or the like, which has been dyed with iodine or the like, may be mentioned. When laminating | stacking the optical film 10 and the polarizing element 21, it is preferable to perform the saponification process to 1 A of transparent base materials. By performing a saponification process, adhesiveness becomes favorable and an antistatic effect can also be obtained.

<< image display device >>

The optical film 10 and the polarizing plate 20 can be incorporated in an image display device and used. As an image display apparatus, a liquid crystal display (LCD), a cathode ray tube display apparatus (CRT), a plasma display (PDP), an electro luminescence display (ELD), a field emission display (FED), a touch panel, a tablet PC, for example. And electronic paper. 5 is a schematic configuration diagram of an image display device incorporating an optical film according to the present embodiment.

The image display device 30 shown in FIG. 5 is a liquid crystal display. The image display device 30 is a protective film 31 such as a triacetyl cellulose film (TAC film), a polarizing element 32, a retardation film 33, and an adhesive layer from the light source side (backlight side) toward the observer side. It has the structure laminated | stacked in order of the liquid crystal cell 35, the adhesive bond layer 36, the retardation film 37, the polarizing element 21, and the optical film 10. The liquid crystal cell 35 arrange | positions a liquid crystal layer, an orientation film, an electrode layer, a color filter, etc. between two glass base materials.

As retardation films 33 and 37, a triacetyl cellulose film and a cycloolefin polymer film are mentioned. As an adhesive agent which comprises the adhesive bond layers 34 and 36, a pressure-sensitive adhesive agent (PSA) is mentioned.

Since the chain metal oxide particles have a high bulk density, the chain metal oxide particles are hardly introduced into the transparent substrate 1 when the permeable solvent penetrates the transparent substrate 1. That is, in the optical film 10 of this embodiment, chain metal oxide particle exists in the 2nd hard-coat layer 6, and is hardly present in the 1st hard-coat layer 5. As shown in FIG. In addition, since the conductive metal oxide particles are chained, the chain metal oxide particles are more likely to form a conductive path than the conductive metal oxide particles alone. Therefore, when the same amount is used for the chain metal oxide particles and the conductive metal oxide particles alone, the chain metal oxide particles can improve the antistatic property than the conductive metal oxide particles alone. Therefore, even if content of a chain metal oxide particle was a small amount of 2-20 mass% with respect to the total solid of the composition for antistatic hard coat layers, the outstanding antistatic property can be obtained.

In this embodiment, since content of a chain metal oxide particle is set as the amount of 2-20 mass% with respect to the total solid of the composition for antistatic hard coat layers, a raise of a haze can be suppressed. Thereby, the fall of the transparency of the antistatic hard coat layer 7 can be suppressed.

In the present embodiment, since the chain metal oxide particles have a high bulk density, it is difficult to sink in the second hard coat layer 6, and although the chain metal oxide particles sink in the second hard coat layer 6. Even though the chain metal oxide particles are in the form of chains, even if they exist near the interface between the first hard coat layer 5 and the second hard coat layer 6, the chain metal oxide particles are the first hard coat layer due to steric hindrance. It is not arranged in the vicinity of the interface between (5) and the second hard coat layer 6. Thereby, it can suppress that the refractive index difference of the 1st hard-coat layer 5 and the 2nd hard-coat layer 6 changes abruptly in the vicinity of these interfaces. In addition, the refractive index of the first hard coat layer 5 changes from the second hard coat layer 6 side toward the light transmissive substrate 1A side so as to gradually approach the refractive index of the light transmissive substrate 1A, and also the light There is no interface between the permeable substrate 1A and the first hard coat layer 5 and between the first hard coat layer 5 and the second hard coat layer 6. Thereby, generation | occurrence | production of an interference fringe can fully be suppressed.

In this embodiment, since chain metal oxide particle | grains are used as an antistatic agent, fallout by chemicals etc. can be suppressed and pencil hardness can be improved.

In this embodiment, the weight average molecular weight which has 10 or more of urethane (meth) acrylates and photopolymerizable functional groups whose weight average molecular weight which has six or more photopolymerizable functional groups in the composition (2) for antistatic hard coat layers is 1000 or more Since at least one of the polymer (meth) acrylates which are 10000 or more is included, the hardness of the antistatic hard coat layer 7 can be improved more.

When the weight average molecular weight which has 6 or more photopolymerizable functional groups contains urethane (meth) acrylate which is 1000 or more in the composition (2) for antistatic hardcoat layers, the antistatic hardcoat layer with respect to the low refractive index layer 8 ( The adhesion of 7) can be further improved.

According to the present embodiment, the photopolymerizable monomer is permeated into the light transmissive substrate 1 by the permeable solvent to form the first hard coat layer 5 which is a part of the antistatic hard coat layer 7, thereby preventing the antistatic hard The adhesiveness between the coat layer 7 and the light transmissive base material 1A is also excellent.

According to the present embodiment, since the chain metal oxide particles are unevenly distributed in the surface layer portion of the antistatic hard coat layer 7, the optical film 10 is less than the case where the chain metal oxide particles are uniformly dispersed in the antistatic hard coat layer. Difficult to curl Further, since chain metal oxide particles are unevenly distributed in the surface layer portion of the antistatic hard coat layer 7, the reflectance is lower than that in the case where the chain metal oxide particles are uniformly dispersed in the antistatic hard coat layer.

Example

In order to demonstrate this invention in detail, an Example is given and described below, but this invention is not limited to these description.

<Production of antistatic hard coat layer composition>

Each component was mix | blended so that it might become a composition shown below, and the composition for antistatic hard coat layers was obtained.

(Composition 1 for antistatic hard coat layer)

Alcohol dispersion liquid of chain | strand antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, Nikki Shokubai Kasei Kabushiki Kaisha): 50 mass parts (10 mass parts of solid content, 40 mass parts of alcohol)

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 45 parts by mass

Urethane acrylate (art resin UN3320HA, Negami Kogyo Co., Ltd., weight average molecular weight 1500, 6 functional, functional group equivalent 250): 45 mass parts

Methyl ethyl ketone (penetrating solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 2 for antistatic hard coat layer)

Alcohol dispersion liquid of chain | strand antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, Nikki Shokubai Kasei Kabushiki Kaisha): 50 mass parts (10 mass parts of solid content, 40 mass parts of alcohol)

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 45 parts by mass

Urethane acrylate (UV1700B, Nippon Kose Industries Co., Ltd., weight average molecular weight 2000, 10 functional, functional group equivalent 200): 45 parts by mass

Methyl ethyl ketone (penetrating solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 3 for Antistatic Hard Coat Layer)

Alcohol dispersion liquid of chain | strand antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, Nikki Shokubai Kasei Kabushiki Kaisha): 50 mass parts (10 mass parts of solid content, 40 mass parts of alcohol)

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 45 parts by mass

Urethane acrylate (art resin UN3320HS, Negami Kogyo Co., Ltd., weight average molecular weight 5000, 15 functional, functional group equivalent 333): 45 parts by mass

Methyl ethyl ketone (penetrating solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 4 for antistatic hard coat layer)

Alcohol dispersion liquid of chain | strand antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, Nikki Shokubai Kasei Kabushiki Kaisha): 50 mass parts (10 mass parts of solid content, 40 mass parts of alcohol)

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 45 parts by mass

Butyl acetate solution of polymer acrylate (beam set 371, manufactured by Arakawa Chemical Co., Ltd., weight average molecular weight 40000, 100 functional, functional group equivalent 400): 69 parts by mass (45 parts by mass of solid content, 24 parts of butyl acetate) part)

Methyl ethyl ketone (penetrating solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 5 for antistatic hard coat layer)

Alcohol dispersion liquid of chain | strand antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, Nikki Shokubai Kasei Kabushiki Kaisha): 50 mass parts (10 mass parts of solid content, 40 mass parts of alcohol)

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 30 parts by mass

Butyl acetate solution of polymer acrylate (beam set 371, manufactured by Arakawa Chemical Co., Ltd., weight average molecular weight 40000, 100 functional, functional group equivalent 400): 46 parts by mass (30 parts by mass of solid content, 16 parts by mass of butyl acetate) part)

Urethane acrylate (UV1700B, Nippon Kose Industries Co., Ltd., weight average molecular weight 2000, 10 functional, functional group equivalent 200): 45 parts by mass

Methyl ethyl ketone (penetrating solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 6 for antistatic hard coat layer)

Alcohol dispersion liquid of chain | strand-shaped antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, Nikki Shokubai Kase Kakushiki Kaisha): 50 mass parts (10 mass parts of solid content, 40 mass parts of alcohol)

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 45 parts by mass

Urethane acrylate (art resin UN333, Negami Kogyo Co., Ltd., weight average molecular weight 5000, bifunctional, functional group equivalent 2500): 45 mass parts

Methyl ethyl ketone (penetrating solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 7 for antistatic hard coat layer)

Alcohol dispersion liquid of chain | strand antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, Nikki Shokubai Kasei Kabushiki Kaisha): 50 mass parts (10 mass parts of solid content, 40 mass parts of alcohol)

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 45 parts by mass

Polymer acrylate (art resin UN7700, Negami Kogyo Co., Ltd., weight average molecular weight 20000, bifunctional, functional group equivalent 10000): 45 mass parts

Methyl ethyl ketone (penetrating solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 8 for Antistatic Hard Coat Layer)

Alcohol dispersion liquid of linear antimony dope tin oxide (dispersion liquid ELCOM-V3560 of chain metal oxide particle, product of Niki Shokubaika Kabushiki Kaisha): 200 mass parts (40 mass parts of solid content, 160 mass parts of alcohol)

Pentaerythritol triacrylate (photopolymerizable monomer, PET30, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 298, trifunctional): 30 parts by mass

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 30 parts by mass

Isopropyl alcohol (non-invasive solvent): 25 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 9 for antistatic hard coat layer)

Alcohol dispersion liquid of chain | strand antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, product of Nikki Shokubai Kasei Kabushiki Kaisha): 50 mass parts (10 mass parts of solid content, 45 mass parts of alcohol)

Pentaerythritol triacrylate (photopolymerizable monomer, PET30, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 298, trifunctional): 45 parts by mass

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 30 parts by mass

Isopropyl alcohol (non-invasive solvent): 140 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 10 for antistatic hard coat layer)

Alcohol dispersion liquid of chain antimony dope tin oxide (dispersion liquid of chain metal oxide particle, ELCOM-V3560, product of Nikki Shokubai Kasei Kabushiki Kaisha): 200 mass parts (40 mass parts of solid content, 160 mass parts of alcohol)

Pentaerythritol triacrylate (photopolymerizable monomer, PET30, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 298, trifunctional): 30 parts by mass

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 30 parts by mass

Methyl ethyl ketone (penetrating solvent): 200 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 11 for antistatic hard coat layer)

Alcohol dispersion liquid of chain antimony dope tin oxide (dispersion liquid of chain metal oxide particles, ELCOM-V3560, product of Nikki Shokubai Kasei Kabushiki Kaisha): 5 mass parts (1 mass part of solid content, 9 mass parts of alcohol)

Pentaerythritol triacrylate (photopolymerizable monomer, PET30, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 298, trifunctional): 49 parts by mass

Dipentaerythritol hexaacrylate (photopolymerizable monomer, DPHA, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 578, 6 functional): 49 parts by mass

Methyl ethyl ketone (penetrating solvent): 172 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 12 for Antistatic Hard Coat Layer)

Methyl isobutyl ketone dispersion of non-chain antimony-doped tin oxide (dispersion of non-chain metal oxide particles, EPT5DL2MIBK, manufactured by Mitsubishi Material Denshi Kasei Co., Ltd.): 50 parts by mass (10 parts by mass of solid content, 40 parts by mass of methyl isobutyl ketone) part)

Pentaerythritol triacrylate (photopolymerizable monomer, PET30, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 298, trifunctional): 30 parts by mass

Urethane acrylate (UV1700B, Nippon Kose Industries Co., Ltd., weight average molecular weight 2000, 10 functional, functional group equivalent 200): 30 parts by mass

Isopropyl alcohol (non-invasive solvent): 25 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

(Composition 13 for antistatic hard coat layer)

Methyl isobutyl ketone dispersion of non-chain antimony-doped tin oxide (dispersion of non-chain metal oxide particles, EPT5DL2MIBK, manufactured by Mitsubishi Material Denshi Kasei Co., Ltd.): 200 parts by mass (40 parts by mass of solid content, 160 parts by mass of methyl isobutyl ketone) part)

Pentaerythritol triacrylate (photopolymerizable monomer, PET30, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 298, trifunctional): 30 parts by mass

Urethane acrylate (UV1700B, Nippon Kose Industries Co., Ltd., weight average molecular weight 2000, 10 functional, functional group equivalent 200): 30 parts by mass

Isopropyl alcohol (non-invasive solvent): 25 parts by mass

Polymerization initiator (irgacure 184, manufactured by BASF): 4 parts by mass

<Production of Composition for Low Refractive Index Layer>

Each component was mix | blended so that it might become a composition shown below, and the composition for hard-coat layers was obtained.

(Composition for Low Refractive Index Layer)

-Methyl isobutyl ketone dispersion liquid of the hollow microparticles | fine-particles silica fine particle (made by Nikki Shokubai Chemical Co., Ltd., average particle diameter: 60 nm): 60 mass parts (20 mass% of solid content)

Pentaerythritol triacrylate (PET30, manufactured by Nippon Kayaku Co., Ltd., trifunctional): 10 parts by mass

Reactive silicone (X22164E, manufactured by Shin-Etsu Chemical Co., Ltd.): 0.6 parts by mass

Methyl isobutyl ketone: 350 parts by mass

Propylene glycol monomethyl ether acetate: 161 parts by mass

Polymerization initiator (irgacure 127, manufactured by BASF): 0.4 parts by mass

&Lt; Example 1 >

The coating film was formed by apply | coating the composition 1 for antistatic hard-coat layers using the roll coat method on one surface of the triacetyl cellulose base material (KC4UY, Konica Minolta Co., Ltd.) of thickness 40micrometer. After drying the coating film at 70 degreeC for 60 second, ultraviolet irradiation was carried out by irradiation amount 100mJ / cm <2> using the ultraviolet irradiation device, and the coating film was hardened. Thereby, the 1st hard-coat layer of the dry film thickness of 4 micrometers containing the polymer of triacetyl cellulose and dipentaerythritol hexaacrylate, the polymer of dipentaerythritol hexaacrylate, and urethane acrylate, and chain | strand antimony dope oxidation An antistatic hard coat layer composed of a second hard coat layer having a dry film thickness of 1.5 μm containing tin was formed. Furthermore, the composition for low refractive index layers was apply | coated to the surface of the 2nd hard-coat layer, and the coating film was formed. After drying the coating film at 70 degreeC for 60 second, ultraviolet irradiation was performed by 150 mJ / cm <2> of irradiation doses using the ultraviolet irradiation device, the coating film was hardened and the low refractive index layer was obtained. Thereby, the optical film in which the antistatic hardcoat layer and the low refractive index layer were formed in this order on the triacetyl cellulose base material was produced.

<Examples 2 to 5 and Comparative Examples 1 to 8>

In Example 2, 3 and Comparative Examples 1-8, the optical film was produced by the method similar to Example 1 except having used the thing shown in Table 1 as a composition for antistatic hard coat layers.

Observation of the cross section of the optical film

The cross section of the optical film produced in the said Example 1 was image | photographed using the scanning transmission electron microscope (STEM) function of a scanning electron microscope (SEM) (S-4800, the Hitachi Kyowa Engineering Co., Ltd. make). The STEM cross section was observed. It is a cross-sectional photograph of the optical film which concerns on Example 1 image | photographed using the scanning transmission electron microscope function of a scanning electron microscope. 7 is a cross-sectional photograph of the vicinity of the surface of the optical film according to Example 1 photographed using the scanning transmission electron microscope function of the scanning electron microscope.

6 and 7, the first hard coat layer is present on the triacetyl cellulose substrate, the second hard coat layer containing the chain metal oxide particles is present on the first hard coat layer, and the second hard coat is present. It was confirmed that the low refractive index layer was present on the layer. 6 and 7, it was confirmed that there is no interface between the triacetylcellulose base material and the first hard coat layer and between the first hard coat layer and the second hard coat layer.

<Evaluation of the optical film>

About the optical film produced in the said Example and the comparative example, the test described below was performed and evaluated respectively.

(Surface resistance measurement)

About each optical film produced by the said Example and the comparative example, surface resistance value was measured using the surface resistance value measuring instrument (Highresta HT-210, the Mitsubishi Yuka Corporation).

(Total light transmittance measurement)

About each optical film produced by the said Example and the comparative example, total light transmittance was measured according to JISK-7361 using the haze meter (HM-150, Murakami Color Research Institute).

(Haze value measurement)

About each optical film produced by the said Example and the comparative example, haze value was measured according to JISK-7361 using the haze meter (HM-150, Murakami Color Research Institute).

(Reflective Y value measurement)

About each optical film produced by the said Example and the comparative example, the reflection Y value was measured using the spectrophotometer (MCP3100, the Shimadzu Corporation Corporation make). In addition, in the measurement of 5 degree specular reflectance for obtaining the reflection Y value, in order to prevent the back reflection of an optical film, black tape (made by Dera-Oka Seisakusho) was stuck to the opposite side to the measurement film surface.

(Pencil hardness test)

The pencil hardness test (4.9 N load) prescribed | regulated to JISK5600-5-4 (1999) was done about the surface of the low refractive index layer of each optical film produced by the said Example and the comparative example. Evaluation criteria were as follows.

○: no scratches / number of measurements = 4/5, 5/5

×: no scratch / measurement count = 0/5, 1/5, 2/5, 3/5

(Interference stripe evaluation)

1. Visual Evaluation

The black tape was affixed to the surface on the opposite side to the surface on which the antistatic hard coat layer in the triacetylcellulose base material of each optical film produced by the said Example and the comparative example was formed, and visually seen under a three wavelength fluorescent lamp. The presence or absence of interference stripes was evaluated. The evaluation criteria are as follows.

(Circle): An interference fringe was not recognized.

X: An interference fringe was confirmed.

2. Spectral Reflectance Evaluation

About each optical film produced by the said Example and the comparative example, the 5 degree regular reflectance was measured using the spectrophotometer (MCP3100, the Shimadzu Corporation make), and the spectral reflectance curve was obtained. And the presence or absence of the ripple (maximum micro wave) in a spectral reflection curve was investigated. In addition, in the measurement of a 5 degree regular reflectance, in order to prevent the back surface reflection of an optical film, black tape (made by Dera-Oka Seisakusho) was stuck on the opposite side to the measurement film surface. The evaluation criteria are as follows.

(Circle): Ripple was not confirmed or ripple was confirmed but very few.

X: Many ripples were confirmed.

(Evaluation of adhesion)

About each optical film produced by the said Example and the comparative example, the board | substrate eye adhesion test was done as adhesive evaluation, and the adhesion rate was computed. The checkerboard eye adhesion test was performed as follows. On the surface of the low refractive index layer side of the optical film, 100 checkerboard eyes were made with a length of 1 mm in total, and five consecutive peel tests were performed using an industrial 24 mm cell tape (registered trademark) manufactured by Nichiban Co., Ltd. The ratio (adhesion rate) of the lattice remaining without was calculated | required. In addition, the adhesion rate was computed based on the following formula | equation.

Adhesion rate (%) = (number of non-peeled plaids / total plaid number 100) x 100

(Steel Wool (SW) Wear Resistance Evaluation)

Each optical film produced by the said Example and the comparative example used the steel wool of # 0000 (brand name "BON STAR", the product made by Nippon Steel Wool Co., Ltd.), applying a load of 300g / cm <2>, the speed | rate 100mm / After rubbing for 10 reciprocating seconds, a black tape was applied to the surface on the side opposite to the surface on which the antistatic hard coat layer was formed on the triacetylcellulose base material, and the presence or absence of scratches was visually evaluated under a three-wavelength fluorescent lamp. The evaluation criteria are as follows.

(Circle): Scratches were not confirmed.

X: Scratches were confirmed.

The evaluation results are shown in Table 1. In addition, "content (mass%) of linear metal oxide particle" described in Table 1 shall mean content of the linear metal oxide particle with respect to the total solid of the composition for antistatic hard coat layers.

As shown in Table 1, the optical films of Examples 1 to 5 have a result of satisfying all of the surface resistance value, the total light transmittance, the haze value, the reflection Y value, the pencil hardness, the interference fringe prevention property, the adhesiveness, and the SW wear resistance. Obtained. Regarding the interference fringe prevention property, it is known that interference fringes generated at the interface between the hard coat layer and the light transparent substrate can be prevented by adding an appropriate amount of a permeable solvent in the hard coat composition. In this case, this permeable solvent alone was insufficient (see results of comparative examples). This is because when an antistatic material such as antistatic fine particles is added, the antistatic material cannot penetrate together with the permeable solvent at a level capable of preventing interference fringes, and thus a new interface due to the antistatic material is prevented. It is considered to be because the interference fringes occurred between the antistatic hard coat layer and the light transmissive substrate. In contrast, in the present invention, since the chain metal oxide particles are used for the antistatic material, it is considered that such an interface does not occur. For this reason, in the Example, favorable interference fringe prevention property is obtained.

On the other hand, the optical films of Comparative Examples 1 to 8 did not obtain the results of satisfying all of the surface resistance value, total light transmittance, haze value, reflection Y value, pencil hardness, interference fringe prevention property, adhesiveness, and SW wear resistance. In Comparative Examples 1 and 2, since the functional group equivalent of urethane (meth) acrylate and polymer (meth) acrylate is too large, Comparative Examples 3 and 5 do not use a permeable solvent, and Comparative Example 6 is a urethane (meth) acrylic Since neither a rate nor a polymer (meth) acrylate is used, it is considered that either of the above performances could not be satisfied.

The result of the surface resistance value in the comparative example 7 is "over" because in the optical film according to the comparative example 7, the amount of the non-chain antimony-doped tin oxide particles is small relative to the binder component. By disperse | distributing uniformly, it is thought that this space | interval becomes large and the conductive path | route is not formed. In addition, the result of the visual evaluation of the interference fringe prevention property in the comparative example 7 becomes "(circle)", In the optical film which concerns on the comparative example 7, non-chain antimony dope tin oxide particle is uniform with respect to the quantity of binder component. Since it is added in an amount sufficient to maintain high dispersibility, it hardly sinks to the first hard coat layer side even though the specific gravity of these particles is higher than that of the binder component. It is considered that the change in the refractive index difference of the hard coat layer is caused by smallness. However, since the refractive index of the whole antistatic hard coat layer is large compared with the comparative example 6, "(circle)" in the visual evaluation of the three wavelength fluorescent lamp of the comparative example 7 is a level which can be used as a product, It is bad at level compared with "○". This showed that the result of the spectral reflectance evaluation of the interference fringe prevention property in the comparative example 7 was set to "x", and was also inadequate as interference fringe prevention property.

Also, the result of the surface resistance value in the comparative example 8, which is a ⁹ × 10 9, in the optical film according to Comparative Example 8, Because of the high amount of a non-linear antimony-doped tin oxide particles, and Comparative Example 7 On the contrary, it is considered that the spacing between these particles is dense and sufficient conductive paths are formed. In the optical film according to Comparative Example 8, a large amount of non-chain antimony-doped tin oxide particles exist in the optical film according to Comparative Example 8 that the results of the visual evaluation and the spectral reflectance evaluation of the interference fringe prevention property in Comparative Example 8 are "x". As a result, not only the refractive index of the antistatic hard coat layer is increased, but also the specific gravity of the particles is large, so that it sinks toward the first hard coat layer side, and the refractive index difference greatly changes at the interface between the first hard coat layer and the second hard coat layer. I think it is because.

1, 1A: light transmissive substrate
2: Photocurable resin composition for antistatic hard coat layer
3: mixed layer
4: chain metal oxide particle containing layer
5: first hard coat layer
6: second hard coat layer
7: antistatic hard coat layer
8: low refractive index layer
10: optical film
20: polarizer
21: polarizing element
30: image display device

Claims (12)

A urethane (meth) acrylate having a weight average molecular weight of 1000 or more having a chain metal oxide particle composed of two or more conductive metal oxide particles connected in a chain on the surface of the light transmissive substrate, a photopolymerizable monomer, and six or more photopolymerizable functional groups. And a polymer (meth) acrylate having a weight average molecular weight of at least 10000 having 10 or more photopolymerizable functional groups, and a permeable solvent having a permeability to the light transmissive substrate, the photocurable resin composition for an antistatic hard coat layer. And dried to form a mixed layer in which the main component of the light transmissive substrate and the photopolymerizable monomer are mixed on the light transmissive substrate, and the chain metal oxide particles, the photopolymerizable monomer and the photopolymerizable monomer on the mixed layer. Urethane (meth) acrylates and the polymer (meth) acrylics Forming a chain metal oxide particle-containing layer containing at least one of the rates;
The mixed layer and the chain metal oxide particle-containing layer are cured by light irradiation to form a first hard coat layer, which is a cured product of the mixed layer, and a hardened product of the chain metal oxide particle-containing layer, formed on the first hard coat layer. A step of forming an antistatic hard coat layer composed of a coat layer,
Content of the said chain metal oxide particle with respect to the total solid of the said photocurable resin composition for antistatic hard coat layers is 2-20 mass%, The manufacturing method of the optical film characterized by the above-mentioned. The manufacturing method of the optical film of Claim 1 whose functional group equivalent of the urethane (meth) acrylate and functional group equivalent of the said polymer (meth) acrylate are 150 or more and 500 or less. The method for producing an optical film according to claim 1, wherein the chain metal oxide particles are made of the conductive metal oxide particles connected in a chain of 2 to 50 chains. The method of claim 1, wherein the conductive metal oxide particles are antimony-doped tin oxide, phosphorus-doped tin oxide, tin-doped indium oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, ZnO, CeO ₂ , Sb ₂ O ₅ , SnO ₂ , the method of the metal oxide particles in the optical film is selected from the group consisting of in ₂ O ₃ and Al ₂ O _3. The optical film production method according to claim 1, wherein the light transmissive substrate is a triacetylcellulose substrate. It is an optical film provided with a transparent base material and the antistatic hard coat layer formed on the said transparent base material,
The antistatic hard coat layer comprises a first hard coat layer formed on the light transmissive substrate, and a second hard coat layer formed on the first hard coat layer,
The first hard coat layer comprises a main component of the light-transmitting substrate and a first binder resin,
The second hard coat layer comprises a chain metal oxide particle composed of two or more conductive metal oxide particles connected in a chain and a second binder resin,
A polymer having a weight average molecular weight of 10000 or more, wherein the second binder resin has 10 or more of a urethane (meth) acrylate having a photopolymerizable monomer and 6 or more photopolymerizable functional groups and a urethane (meth) acrylate having 1000 or more and a photopolymerizable functional group (meth) At least one polymer of acrylate,
The refractive index of the first hard coat layer is changed to gradually approach the refractive index of the light transmissive substrate from the second hard coat layer side toward the light transmissive substrate side.
No optical interface exists between the light transmissive substrate and the first hard coat layer and between the first hard coat layer and the second hard coat layer. The optical film according to claim 6, wherein the functional group equivalent of the urethane (meth) acrylate and the functional group equivalent of the polymer (meth) acrylate are 150 or more and 500 or less. The optical film according to claim 6, wherein the chain metal oxide particles are made of the conductive metal oxide particles connected in a chain of 2 to 50 chains. The method of claim 6, wherein the conductive metal oxide particles are antimony-doped tin oxide, phosphorus-doped tin oxide, tin-doped indium oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, ZnO, CeO ₂ , Sb ₂ O ₅ , SnO ₂ , An optical film which is particles of a metal oxide selected from the group consisting of In ₂ O ₃ and Al ₂ O ₃ . The optical film of claim 6, wherein the light transmissive substrate is a triacetylcellulose substrate. The optical film of Claim 6,
The polarizing plate provided with the polarizing element formed in the surface on the opposite side to the surface in which the said 1st hard-coat layer in the said light transmissive base material of the said optical film is formed. The optical film of Claim 6 or the polarizing plate of Claim 11 is provided, The image display apparatus characterized by the above-mentioned.

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