TWI482705B - Curable resin composition for antistatic layer, optical film, polarizing plate and display panel - Google Patents

Description

Curable resin composition for antistatic layer, optical film, polarizing plate and display panel

The present invention relates to a display (image display device) such as a liquid crystal display (LCD), a cathode tube display device (CRT), or a plasma display panel (PDP). An optical film having an antistatic layer and a composition for the antistatic layer, and a polarizing plate and a display panel using the optical film.

In the above display, an optical film including a layer having various functions such as antireflection, hard coat, or antistatic property is usually provided on the outermost surface. Further, in the present specification, the hard coat may be simply referred to as "HC".

As one of the functional layers of such an optical film, an antistatic layer for imparting antistatic properties is known. The antistatic layer is made of a metal oxide-based conductive ultrafine particle or a polymer doped with antimony tin oxide (ATO, Antimony Tin Oxide) or tin-doped indium oxide (ITO, Indium Tin Oxide). An antistatic agent such as a conductive composition or a quaternary ammonium salt conductive material is formed (for example, Patent Document 1). In the case of using such an antistatic agent, in order to cope with the required antistatic property and optical properties (low haze value or high total light transmittance), a film of about 0.1 to 1 μm containing an antistatic agent is formed. Layers to give the desired functionality.

Further, in the above display, it is required to impart hardness to the image display surface of the display so as not to be damaged during processing. On the other hand, Patent Document 1 discloses a configuration in which an optical film is provided on a cellulose triacetate (hereinafter, simply referred to as a "TAC (Triacetyl Cellulose)" substrate, and an antistatic layer is provided thereon. An HC layer is disposed on the antistatic layer.

However, the antistatic layer-based film has a problem in that pentaerythritol triacrylate (hereinafter referred to as "PETA (Pentaerythritol triacrylate)" or dipentaerythritol hexaacrylate (hereinafter sometimes referred to as "PETA") The amount of the binder component and the antistatic agent, which are simply referred to as "DPHA (Di-Pentaerythritol hexaacrylate)", is limited, and the adhesion to the HC layer adjacent to the antistatic layer is likely to be insufficient.

The optical film having a base material/antistatic layer/HC layer as a basic structure has an interface between the antistatic layer and the HC layer, and an interface between the antistatic layer and the substrate, and has adhesion at each interface. The problem.

At the interface between the antistatic layer and the HC layer, the reactive groups of the antistatic layer and the HC layer are crosslinked and bonded to each other, but at the same time, the antistatic layer is required to exhibit antistatic properties. When the antistatic agent is a metal oxide, in order to exhibit antistatic properties for the antistatic layer, the microparticles of the antistatic agent must be in close contact with each other. Therefore, a large amount of the antistatic agent is added, but the fog value increases or the total light transmittance deteriorates. The situation. However, if the optical properties are emphasized and the amount of metal oxide is reduced, the antistatic performance is difficult to exert. Moreover, when the amount of the antistatic agent is increased, the amount of the binder component is insufficient at the interface between the antistatic layer and the adjacent layer, and the adhesion between the antistatic layer and the adjacent layer may be deteriorated. However, if the adhesion is emphasized and the amount of the metal oxide is reduced, the antistatic performance is difficult to exert.

In the case where the antistatic agent is a quaternary ammonium salt, in order to exhibit antistatic properties of the antistatic layer, more quaternary ammonium salts than the binder must be present in the layer. Alternatively, the quaternary ammonium salt must be concentrated in the vicinity of the interface of the antistatic layer adjacent to the HC layer. However, in such a case, there is a possibility that the quaternary ammonium salt present in the vicinity of the interface hinders the adhesion between the antistatic layer and the HC layer, and the binder component at the interface between the antistatic layer and the adjacent HC layer (having The amount of the component which increases the reactivity of the crosslinking layer with the HC layer is insufficient, and the adhesion between the antistatic layer and the adjacent HC layer is deteriorated. However, if the adhesion is emphasized and the amount of the quaternary ammonium salt is reduced, the antistatic property is deteriorated.

In order to coexist antistatic property and adhesion, a method of simply increasing the amount of the binder component such as PETA (pentaerythritol triacrylate) or DPHA (dipentaerythritol hexaacrylate) may be considered, but if such a binder component is added In this case, the film thickness of the antistatic layer is increased, and accordingly, there is a problem that the curl (warpage) of the antistatic layer becomes large, and the use amount of the expensive antistatic agent dispersed in the antistatic layer is also increased. And the problem of increased costs. Further, in order to improve the adhesion, a method of increasing a component having a reactive group in the binder may be considered. However, as described above, the amount of the binder is limited in order to exhibit an antistatic property, and the amount of the binder is limited. It is therefore difficult to adopt this method.

Further, as described above, since the total amount of the binder component and the antistatic agent contained in the layer of the antistatic layer as the film is limited, if the amount of the antistatic agent is to be reduced, the use of the binder component is accordingly increased. When the amount of the antistatic layer and the HC layer are improved, the amount of the antistatic agent used is reduced to cause a problem that the antistatic property is lowered.

On the other hand, at the interface between the antistatic layer and the substrate, in order to adhere the antistatic layer to the substrate, it is necessary to infiltrate the binder component of the composition of the antistatic layer into the substrate, and in the substrate and At the interface of the antistatic layer, the binder component that penetrates into the substrate hardens and bonds with the binder component that forms the antistatic layer.

In the case where the antistatic agent is a quaternary ammonium salt, it is known to use a quaternary ammonium salt having a relatively large molecular weight in order to improve durability or antistatic property. However, if the molecular weight of the quaternary ammonium salt is large, the binder component of the composition of the antistatic layer is difficult to penetrate into the substrate, and therefore, in order to obtain the adhesion between the antistatic layer and the substrate, it is necessary to use a large amount of the permeable solvent. Or use a binder of a lower molecular weight that can penetrate into the substrate. However, in this case, there is a problem that the adhesion between the interface of the antistatic layer and the HC layer is deteriorated.

Further, it has been known that a barrier resin can be prevented by using a permeable solvent, and the appearance can be improved. However, when a permeable solvent is used, a new interface may be formed in the substrate. In addition to the above-described deterioration in adhesion, there is also a problem that interference fringes are generated and the appearance is deteriorated.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-086660

The present invention has been made to solve the above problems, and a first object thereof is to provide a curable resin composition for an antistatic layer which can form optical characteristics, good appearance, and antistatic property. An antistatic layer which is sufficient and has excellent adhesion to the adjacent HC layer and TAC substrate.

Further, a second object of the present invention is to provide an optical film which has an antistatic layer formed using the above composition and which is excellent in dust adhesion prevention property.

Further, a third object of the present invention is to provide a polarizing plate comprising the above optical film.

Further, a fourth object of the present invention is to provide a display panel having the above optical film.

As a result of intensive studies, the inventors of the present invention have found that the adhesive component contained in the composition of the antistatic layer is used to increase the crosslinking density with the adjacent HC layer and to obtain adhesion. A binder having a molecular weight of less than 900, such as DPHA, which is relatively small in molecular weight, may be substantially completely infiltrated into the TAC substrate, or may be formed from the surface of the TAC substrate belonging to the interface with the HC layer to the TAC substrate according to the binder component. The degree of penetration of the back side of the HC layer in the depth direction causes the binder component to be deposited in the substrate, and the binder component contained in the antistatic layer on the substrate is reduced, and the interface between the HC layer and the antistatic layer is reacted. Since the composition is insufficient, the adhesion between the antistatic layer and the HC layer may not be sufficiently obtained. Moreover, it is also known that if the portion penetrating into the interior of the TAC substrate does not penetrate in a gradient form, but the infiltrated material all penetrates to the same depth in the TAC substrate, a binder penetration layer is formed in the TAC substrate. On the other hand, a new interface is generated in the substrate, and interference fringes and the like are generated to deteriorate the appearance.

Therefore, the present inventors have found that an acrylic urethane having a specific molecular weight which is contained in the composition and which is a binder component which is difficult to penetrate into the TAC substrate or does not penetrate into the TAC substrate is found. And the binder component (polyfunctional monomer) permeating to the TAC substrate is set to a specific ratio, and an antistatic layer having sufficient antistatic property and excellent adhesion to the HC layer and the TAC substrate can be formed as The optical film as a whole can obtain excellent dust adhesion preventing performance, thereby completing the present invention.

That is, the curable resin composition for an antistatic layer of the present invention which solves the above problems is characterized by comprising:

(A) antistatic agent,

(B) a polyfunctional monomer having two or more photocurable groups in one molecule and having a molecular weight of 900 or less, and

(C) an urethane urethane having 6 or more acryl fluorenyl groups and/or methacryl fluorenyl groups in one molecule and having a weight average molecular weight of 1,000 to 11,000.

The ratio of the (A) to the total amount of the (A), (B), and (C) is 1 to 30% by mass, and the ratio of the (C) to the total amount of the (B) and (C) It is 1 to 40% by mass.

By setting the ratio of the antistatic agent (A) to the above range, the antistatic layer having a film thickness of 1 to 5 μm formed using the above composition has sufficient antistatic property, even if a layer of HC is laminated thereon. In the case of forming an optical film, sufficient dust adhesion prevention property is also ensured.

In the past, the film thickness of the antistatic layer was set to be about 0.1 to 1 μm due to optical properties and transparency. However, in order to impart antistatic properties, it is necessary to have a large composition in the layer. Some of them are antistatic materials, and therefore it is not possible to add a sufficient amount of some binder having a reactive group necessary for exhibiting adhesion to a substrate or a layer above it. Therefore, in the present invention, the film thickness is increased to a certain extent, and the adhesion between the antistatic layer and the adjacent layer is ensured, so that the addition of the binder component having a reactive group other than the antistatic material can be sufficiently changed. It is possible.

Further, by setting the ratio of the urethane urethane (C) to the total amount of the polyfunctional monomer (B) and the urethane acrylate (C) to the above range, even on the TAC substrate The antistatic layer and the HC layer are sequentially formed on the TAC substrate side, and the urethane urethane (C) does not penetrate into the TAC substrate or is more difficult to penetrate into the TAC group than the polyfunctional monomer (B). In the material, sufficient adhesion between the antistatic layer and the HC layer can be obtained by the urethane urethane (C), and since the polyfunctional monomer (B) penetrates into the TAC substrate, it can also be obtained. Adhesion between the antistatic layer and the TAC substrate.

In the curable resin composition for an antistatic layer of the present invention, it is preferred that the antistatic agent (A) has a weight average molecular weight of 1000 to 100% in terms of inhibiting penetration of the antistatic agent into the TAC substrate and excellent coating properties. Quaternary ammonium salt of 50000.

In the curable resin composition for an antistatic layer of the present invention, it is preferable to further contain (D) permeation from the viewpoint of enhancing the action of the polyfunctional monomer (B) and the urethane acrylate (C). Solvent and (E) non-permeable solvent.

In the curable resin composition for an antistatic layer of the present invention, the surface resistivity of the cured product having a thickness of 1 to 5 μm of the curable resin composition for an antistatic layer may be less than 1 × 10 ^{12 .} Ω/□. An optical film formed by laminating a hard coat layer of 5 to 15 μm on an antistatic layer by using a cured product (that is, an antistatic layer) of a curable resin composition for an antistatic layer is used as such an antistatic property. Dust adhesion prevention.

In addition, the surface resistance value is a cured product (antistatic layer) having a thickness of 1 to 5 μm in which the curable resin composition for an antistatic layer is formed on a TAC substrate, and then a high resistivity meter is used. (Mitsubishi Chemical Analytech Co., Ltd., trade name: Hiresta IP MCP-HT260), the value obtained by measuring the surface of the cured product under the conditions of a voltage of 1000 V, a temperature of 25 ° C, and a humidity of 40% for 24 hours. .

The optical film of the present invention is one surface side of a cellulose triacetate substrate, and is formed by providing an antistatic layer and a hard coat layer having a film thickness of 1 to 5 μm from the side of the cellulose triacetate substrate. The antistatic layer contains a cured product of the curable resin composition for an antistatic layer, and the polyfunctional monomer (B) penetrates into a region near the interface of the antistatic layer side of the triacetylcellulose substrate and hardens. .

An optical film of the present invention having an antistatic layer and an HC layer having a film thickness of 1 to 5 μm from the side of the TAC substrate on one side of the TAC substrate, wherein the antistatic layer comprises the curable resin for the antistatic layer. Hardened material with sufficient dust adhesion prevention. Further, the adhesion between the HC layer and the antistatic layer is excellent. Further, the polyfunctional monomer (B) is infiltrated into the region on the interface side of the antistatic layer side of the TAC substrate and cured, and the adhesion between the antistatic layer and the TAC substrate can also be obtained. As the entire optical film, excellent dust adhesion prevention performance can be obtained.

In a preferred aspect of the optical film of the present invention, the adhesion ratio of the hard coat layer, the antistatic layer, and the triacetylcellulose substrate may be determined to be 90 to 100%. The adhesion rate after ultraviolet irradiation for 192 hours at a temperature of 30 ° C and a humidity of 40% at a light amount of 500 W/m ² per hour was set to be 80 to 100%.

In addition, the close contact rate of the Cross Cut Adhesion Test is an optical film after the humidity is adjusted to a temperature of 25 ° C and a humidity of 40% for 24 hours. According to JIS K5400, the Cross Cut Test In this way, 11 slits were cut into the surface of the hard-coated surface at intervals of 1 mm to make 100 squares. After attaching the Cellotape (registered trademark) manufactured by Nichiban to the square, it was quickly placed at 90. The ratio of the squares which were stretched in the direction of ° and peeled off, and which were not peeled off according to the following criteria.

Bonding rate (%) = (number of squares without peeling off / total number of squares 100) × 100

In a preferred aspect of the optical film of the present invention, a low refractive index layer may be further provided on the surface of the hard coat layer opposite to the antistatic layer.

In a preferred aspect of the optical film of the present invention, the hard coat layer may be used as a cured product containing a composition of an ionizing radiation curable resin.

The polarizing plate of the present invention is characterized in that a polarizer is provided on the side of the cellulose triacetate substrate of the optical film.

The display panel of the present invention is characterized in that a display is disposed on the cellulose acetate substrate side of the optical film.

An antistatic layer having a film thickness of 1 to 5 μm is formed by curing a composition containing the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) in the specific ratio described above. Even if it is a layer structure having an antistatic layer and an HC layer from the TAC substrate side on the TAC substrate, sufficient dust adhesion prevention property can be obtained, and an antistatic layer can be obtained in close contact with the TAC substrate and the HC layer. A good optical film. Further, the composition containing the antistatic agent (A), the polyfunctional monomer (B) and the urethane acrylate (C) in the above specific ratio can be preferably used for forming such a characteristic. An antistatic layer used in optical films.

Hereinafter, the curable resin composition for an antistatic layer of the present invention (hereinafter sometimes referred to simply as "the composition for an antistatic layer"), an optical film, and a polarizing plate and a display panel using the same will be described.

In the present invention, (meth)acryl fluorenyl represents an acryl fluorenyl group and/or a methacryl fluorenyl group, and (meth) acrylate means an acrylate and/or a methacrylate.

The light of the present invention includes not only electromagnetic waves of visible light but also wavelengths of non-visible regions such as ultraviolet rays and X-rays, and also includes particle beams such as electron beams and radiation or ionizing radiation collectively referred to as electromagnetic waves and particle beams.

In the present invention, the term "hard coating layer" means a hardness of "H" or more in a pencil hardness test (4.9 N load) prescribed in JIS K5600-5-4 (1999).

Further, regarding the film and the sheet, as defined in JIS-K6900, the sheet refers to a flat product which is thin and generally has a thickness smaller than the length and the width, and the film means that the thickness is extremely small and maximum in comparison with the length and the width. A thin, flat article of arbitrarily defined thickness, which is typically supplied in the form of a roll. Therefore, the thickness of the sheet is particularly thin, which may be referred to as a film. However, since the boundary between the sheet and the film is not clear, it is difficult to distinguish clearly. Therefore, in the present invention, both the thicker and the thinner are included. The meaning is defined as "film".

In the present invention, the resin includes a polymer in addition to a monomer or an oligomer, and means a component which becomes a matrix of an antistatic layer or another functional layer such as an HC layer after curing.

In the present invention, the molecular weight as used in the case of having a molecular weight distribution means polystyrene conversion as measured by gel permeation chromatography (GPC, Gel Permeation Chromatograph) in a solvent of THP (Tetrahydrofuran). The weight average molecular weight of the value, when not having a molecular weight distribution, refers to the molecular weight of the compound itself.

In the present invention, the average particle diameter of the fine particles in the case of the fine particles in the composition refers to the value measured by the Microtrac particle size analyzer manufactured by the Japanese machine (strand), and the case of the fine particles in the cured film. In the meantime, it means an average value of 10 particles of a cross section of the cured film observed by a transmission electron microscopy (TEM) photograph.

In the present invention, the term "permeation" means that the TAC substrate is dissolved or swollen.

In the present invention, the solid portion means a component from which a solvent is removed.

(curable resin composition for antistatic layer)

The curable resin composition for an antistatic layer of the present invention is characterized by comprising:

(A) antistatic agent,

(B) a polyfunctional monomer having two or more photocurable groups in one molecule and having a molecular weight of 900 or less, and

(C) an urethane urethane having 6 or more (meth) acrylonitrile groups in one molecule and having a weight average molecular weight of 1,000 to 11,000.

The ratio of the (A) to the total amount of the (A), (B), and (C) is 1 to 30% by mass, and the ratio of the (C) to the total amount of the (B) and (C) It is 1 to 40% by mass.

By setting the ratio of the antistatic agent (A) to the above range, the antistatic layer can impart antistatic properties, and even when the HC layer is formed on the antistatic layer having a film thickness of 1 to 5 μm, sufficient securing is ensured. The dust adhesion prevention.

Further, the ratio of the urethane urethane (C) to the total amount of the polyfunctional monomer (B) and the urethane acrylate (C) is in the above range, and is self-contained on the TAC substrate. The antistatic layer and the HC layer are sequentially formed on the TAC substrate side, since the urethane urethane (C) does not penetrate into the TAC substrate, or is less permeable to the polyfunctional monomer (B). In the TAC substrate, the urethane urethane (C) and the (meth) acrylonitrile and HC layer of the urethane urethane (C) are also present at the interface between the antistatic layer and the HC layer. The reactive group hardening is combined, whereby sufficient adhesion between the antistatic layer and the HC layer can be obtained.

Further, the polyfunctional monomer (B) is moderately infiltrated into the TAC substrate (not uniformly penetrated to the same depth, but penetrated in a gradient form), and the infiltrated polyfunctional monomer (B) present in the TAC substrate Reactive group (photocurable group) and reactive group of polyfunctional monomer (B) present in antistatic layer and reactive group of urethane urethane (C) ((meth) propylene The sulfhydryl group is hardened and bonded, so that the adhesion between the antistatic layer and the TAC substrate can also be obtained.

In the following, the antistatic agent (A), the polyfunctional monomer (B), and the urethane urethane (C) which are essential components of the composition for an antistatic layer of the present invention, and, if necessary, are appropriately contained. Other ingredients are explained.

(A: antistatic agent)

The antistatic agent (A) imparts conductivity to the antistatic layer or the optical film which is a cured film of the composition for an antistatic layer to prevent electrification, and has the effect of preventing dust or dust from adhering or causing malfunction in the step due to charging. A component that acts as a property (ie, antistatic).

As the antistatic agent (A), a conventionally known antistatic agent can be used, and it is not particularly limited.

For example, a cationic compound such as a quaternary ammonium salt described in Patent Document 1, an anionic compound such as a sulfonate, an amphoteric compound such as an amino acid, a nonionic compound such as an amino alcohol, or an organometallic compound can be given. And a metal chelate compound, a compound obtained by polymerizing the compound, a polymerizable compound, conductive ultrafine particles such as indium tin oxide (ITO) having an average primary particle diameter of 1 to 100 nm, and an aliphatic group. A polymer type conductive composition such as a polyacetylene of a yoke system.

In the curable resin composition for an antistatic layer of the present invention, it is preferable to suppress the penetration of the antistatic agent (A) into the TAC substrate and to improve the coatability, and it is preferable that the antistatic agent (A) is an average weight. A quaternary ammonium salt having a molecular weight of from 1,000 to 50,000. When the above upper limit is exceeded, the coating property of the composition is deteriorated. When the amount is less than the lower limit, the antistatic agent easily bleeds out to the interface between the antistatic layer and the HC layer, and the adhesion between the antistatic layer and the HC layer is deteriorated. The possibility.

Conventionally, the film thickness of the antistatic layer is set to a film of about 0.1 to 1 μm due to optical properties and transparency. However, in the case of such a film layer, it is necessary to provide most of the composition in the layer in order to impart antistatic properties. Since it is an antistatic material, it is difficult to add a sufficient amount of the resin composition which has a reactive group necessary for the adhesiveness with the board|substrate or the layer above. Therefore, in the present invention, the film thickness is set to 1 to 5 μm, which is thicker than before, and the adhesion between the antistatic layer and the adjacent layer is ensured, so that a resin having a reactive group other than the antistatic material can be sufficiently obtained. The addition of the composition becomes possible. Since the film thickness is increased, it is preferable that the added antistatic agent selects a material having high transparency. In this respect, an organic material having higher transparency than an inorganic material is preferred, and among the organic materials, a quaternary ammonium salt having a very small coloration is most suitable. When a quaternary ammonium salt is used, when the transparent substrate is TAC, the total light transmittance of the entire optical film can be made 90% or more, which is also preferable. Further, the haze value may be made 0.5% or less. The total light transmittance can be measured by HM150 manufactured by Murakami Color Technology Research Institute according to JIS K7361 (1997), and the haze value can be measured by HM150 manufactured by Murakami Color Technology Research Institute according to JIS K7136 (2000).

Further, in terms of improving the adhesion between the antistatic layer and the HC layer by crosslinking reaction between the HC layer and the binder component, it is preferred that the quaternary ammonium salt has a photocurable group. The photocurable group is preferably a polymerizable unsaturated group, and more preferably an ionizing radiation curable unsaturated group. Specific examples thereof include a group having an ethylenically unsaturated bond such as a (meth)acryl fluorenyl group, a (meth) acryloxy group, a vinyl group, and an allyl group, and an epoxy group.

As a commercial item of such a quaternary ammonium salt having a weight average molecular weight of 1,000 to 50,000, for example, the trade name H6100 manufactured by Mitsubishi Chemical Corporation and the trade name Uniresin AS-10 manufactured by Shin-Nakamura Chemical Industry Co., Ltd. /M, Uniresin AS-12/M, Uniresin AS-15/M and Uniresin ASH26, etc.

The antistatic layer composition contains 1 to 30% by mass of antistatic against the total amount of the antistatic agent (A) and the polyfunctional monomer (B) and the urethane acrylate (C) described later. Agent (A).

If the ratio of the antistatic agent (A) is less than 1% by mass based on the total amount (A+B+C), sufficient antistatic properties cannot be obtained. In addition, when the ratio of the antistatic agent (A) exceeds 30% by mass based on the total amount (A+B+C), the polyfunctional monomer (B) and the acrylamide carboxylic acid in the composition for an antistatic layer are used. The ratio of the ester (C) is reduced, and sufficient adhesion between the antistatic layer and the TAC substrate or the HC layer adjacent to the layer cannot be obtained.

The ratio of the antistatic agent (A) is from 1 to 30% by mass, preferably from 5 to 20% by mass, based on the total amount (A+B+C).

(B: polyfunctional monomer)

The polyfunctional monomer (B) is one of the binder components of the antistatic layer matrix after curing, and is a monomer having a molecular weight of 900 or less having two or more photocurable groups in one molecule. It is a component which has a small molecular weight and contributes to an improvement in the adhesion density in the antistatic layer or the HC layer adjacent to the antistatic layer by the polyfunctionality, and improves the adhesion. Moreover, the polyfunctional monomer penetrates into the TAC substrate by at least a portion thereof and hardens, and also helps to improve the adhesion between the antistatic layer and the TAC substrate.

When the molecular weight of the polyfunctional monomer (B) exceeds 900, the permeability to the TAC substrate is lowered, and there is a possibility that sufficient adhesion between the antistatic layer and the TAC substrate cannot be obtained.

The molecular weight of the polyfunctional monomer (B) may be 900 or less, but the polyfunctional monomer (B) is appropriately infiltrated into the TAC substrate, and the antistatic layer and the HC layer are adhered and antistatic ( The molecular weight of the polyfunctional monomer (B) is preferably 230 or more, and more preferably 290 or more, from the viewpoint of high surface resistance. If the molecular weight is less than 230, the polyfunctional monomer (B) penetrates into the TAC substrate and is uncomfortable, and all of them penetrate to the same depth to create a new interface, and the light reflected at the interface thereof The light reflected by the interface between the antistatic layer and the HC layer or the light reflected on the surface of the HC layer generates light interference, and the possibility of disturbing the stripes causes deterioration of appearance.

As the polyfunctional monomer (B), one type or two or more types can be used.

The photocurable group of the polyfunctional monomer (B) is two or more in order to form a crosslinked structure, preferably three or more, and more preferably five or more. When it is three or more, it is easy to obtain sufficient adhesiveness of the antistatic layer, the HC layer, and the TAC substrate. The photocurable group is the same as the photocurable group listed in the antistatic agent.

Examples of the polyfunctional monomer (B) include pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, and trimethylolpropane tris(methyl). Acrylates and trimethylolpropane hexa(meth) acrylate and such modified bodies.

Further, examples of the modified body include an EO (Ethylene oxide) modified body, a PO (Propylene oxide) modified body, and a CL (Caprolactone, caprolactone) modified body and a modified form. Cyanuric acid modified body, etc.

Among the above polyfunctional monomers, the photocurable group is more preferably an acrylonitrile group than the methacrylium oxime from the viewpoint of curing reactivity.

As the polyfunctional monomer (B), dipentaerythritol pentaacrylate (DPPA, dipentaerythritol pentaacrylate) or dipentaerythritol hexaacrylate (DPHA) can be preferably used.

In the antistatic layer composition of the present invention, the polyfunctional monomer (B) satisfies the content ratio of the above antistatic agent, and is based on the polyfunctional monomer (B) and an urethane urethane (C) described later. The total amount is 60 to 99% by mass. If it is less than 60% by mass, sufficient adhesion between the antistatic layer and the HC layer and the TAC substrate cannot be obtained. On the other hand, when it exceeds 99% by mass, the ratio of the urethane amide (C) is small, and sufficient adhesion between the antistatic layer and the HC layer cannot be obtained.

(C: urethane acrylate)

The urethane urethane (C) is one of the binder components of the antistatic layer matrix after curing, and has six or more (meth) acrylonitrile groups in one molecule, and the weight average molecular weight is from 1,000 to 11,000. It is preferably from 1,000 to 10,000, more preferably from 1,000 to 5,000.

By having a weight average molecular weight of 1000 to 11,000, good coatability, impermeability into the TAC substrate, or less penetration into the TAC substrate than the polyfunctional monomer (B), it is easy to control the permeation, and surely Present in the entire antistatic layer.

When the antistatic agent (A) is a quaternary ammonium salt, the compatibility with the hydrophilic compound is preferred as the properties of the compound. Therefore, if the binder in the antistatic layer is a compound having an OH group (PETA, PETTA (pentaerythritol tetraacrylate), DPPA (dipentaerythritol pentaacrylate), etc.), the antistatic agent is excessively dispersed throughout the layer, and Antistatic properties are not available. It is known that DPHA does not contain an OH group in a structural formula, but it is generally difficult to form a 100% hexafunctional group by synthesis, and thus it is actually a mixed compound of a 5-functional or a tetra-functional moiety, since a resin which is usually commercially available remains. The compound of the OH group cannot provide better antistatic properties.

The dispersible person can be controlled to be an acrylic urethane (C) which is a hydrophobic resin. By allowing the urethane acrylate (C) to be present throughout the layer, when the antistatic agent (A) is a quaternary ammonium salt system, the antistatic agent can be surely controlled to be excessively dispersed in the layer, or The situation in which the interface with the HC oozes out. The reason why it is easy to bleed out in the direction of the HC interface is that, as described above, since the quaternary ammonium salt is hydrophilic, when the antistatic layer is hardened, air is present on the surface thereof, and it reacts with the moisture in the air to ooze out.

Moreover, by having 6 or more (meth) acrylonitrile groups, it is possible to increase the crosslinking density in the antistatic layer or the reactive groups in the HC layer adjacent to the antistatic layer, and to enhance the antistatic layer. Adhesion to the HC layer. Further, the reactive group of the polyfunctional monomer (B) which penetrates the antistatic layer of the TAC substrate and the (meth)acrylic acid amide of the urethane amide (C) present in the antistatic layer are increased. The crosslink density of the reactive groups of the base or polyfunctional monomer, so that the urethane acrylate (C) also contributes to the adhesion between the antistatic layer and the TAC substrate. In the case of self-adhesiveness, the urethane (C) is not added, as long as the polyfunctional monomer (B) having a large amount of reactive groups other than the antistatic agent (A) is used, but In order to control the fluctuation of the antistatic agent (A) in the antistatic layer as described above, it is difficult to control only the polyfunctional monomer (B), and it is required to be hydrophobic and has a large amount in order to prevent the antistatic agent (A) from being dispersed. Reactive acrylic amide (C).

Further, the urethane-containing acrylate (C) is also effective for suppressing the occurrence of curl (warpage).

If the weight average molecular weight of the urethane acrylate (C) is less than 1,000, there is a possibility that the urethane acrylate (C) easily penetrates into the TAC substrate and excessively penetrates into the TAC substrate. The acrylonitrile group at the interface between the antistatic layer and the HC layer is reduced, and it is difficult to obtain the adhesion between the antistatic layer and the HC layer.

When the weight average molecular weight of the urethane urethane (C) exceeds 11,000, there is a possibility that the coatability is deteriorated.

When the urethane urethane (C) has six or more (meth) acrylonitrile groups, it may contain other crosslinking reactive functional groups such as ionizing radiation curable unsaturated groups. The (meth)acrylonyl group may have only 6 or more acrylonitrile groups and a methacrylium group, and may have only an acryloyl group or only a methacryl group.

The urethane urethane (C) of the present invention has a urethane bond (-NH-CO-O-), has 6 or more (meth) acrylonitrile groups, and has the above weight average. The molecular weight is not particularly limited. The urethane acrylate (C) is preferably one which is light-transmitting when it is formed into a coating film, and may be suitably hardened by ionizing radiation represented by ultraviolet rays or electron beams according to required properties and the like. The ionizing radiation-curable urethane urethane of the resin, other known urethane acrylates, and the like.

As a commercial item of the said urethane amide, the brand name UV1700B manufactured by the Japan Synthetic Chemical Industry Co., Ltd., and the brand name UN3320HS manufactured by Gyeongsei Industrial Co., Ltd., and Arakawa Chemical Industry are mentioned, for example. The trade name BS577 manufactured by the company and the trade names U15HA, U15H, U9HA, U9H, U6HA and U6H manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

In the composition for an antistatic layer of the present invention, the urethane acrylate (C) satisfies the content ratio of the above antistatic agent, and is relative to the above polyfunctional monomer (B) and urethane acrylate ( The total amount of C) is 1 to 40% by mass. If it is less than 1% by mass, sufficient adhesion between the antistatic layer and the HC layer cannot be obtained. On the other hand, when it exceeds 40% by mass, the proportion of the polyfunctional monomer (B) is small, and sufficient adhesion between the antistatic layer and the TAC substrate cannot be obtained.

The ratio of the urethane acrylate (C) is from 1 to 40% by mass, preferably from 5 to 30% by mass, based on the total amount (B+C).

Thus, by the ratio of the polyfunctional monomer (B) and the urethane acrylate (C) in the binder, the antistatic agent (A) is neither excessively dispersed nor exuded in the antistatic layer. It can be concentrated in the layer to the extent that it can exert antistatic properties. Because of this composition, the surface resistivity of the antistatic layer can be less than 1 × 10 ¹² Ω / □.

The antistatic layer composition may contain, in addition to the above components (A), (B) and (C), a suitable solvent and a polymerization initiator. Hereinafter, these other components will be described.

(solvent)

As the solvent, a ketone solvent such as acetone described in Patent Document 1, an ester solvent such as methyl acetate, a nitrogen-containing solvent such as acetonitrile, a glycol solvent such as methyl glycol, or an ether solvent such as THF can be used. A osmotic solvent such as a halogenated hydrocarbon solvent such as dichloromethane or a glycol ether solvent such as methyl sarbuta.

As the osmotic solvent, it is preferably selected from the group consisting of methyl acetate, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone (MIBK, Methyl Isobutyl Ketone) and cyclohexanone. At least one of them.

Further, a non-permeable solvent such as propylene glycol monomethyl ether (PGME, Propylene Glycol Monomethyl Ether), n-propanol, isopropanol, n-butanol, second butanol, isobutanol or tert-butanol can also be used.

These solvents may be used singly or in combination of two or more.

In the composition for an antistatic layer of the present invention, it is presumed that by using a permeable solvent, the penetration of the above polyfunctional monomer (B) into the TAC substrate can be promoted, and the adhesion between the antistatic layer and the TAC substrate can be improved. In other words, it is preferred to use a permeable solvent.

Further, in the composition for an antistatic layer of the present invention, it is presumed that by using a non-permeable solvent, the penetration of the urethane urethane (C) toward the TAC substrate can be suppressed, and the antistatic layer and the HC layer can be lifted. In terms of adhesion, it is preferred to use a non-permeable solvent.

Therefore, in the composition for an antistatic layer of the present invention, it is preferred to use a penetrating solvent when the solvent is one, but it is preferable to use a penetrating solvent and a non-permeability in the case of two or more solvents. The solvent is used in combination. The reason for this is that although the permeation can be controlled by the molecular weight of the urethane urethane (C) even if it is a solvent (permeating only the solvent), it is easier to use the osmotic solvent in combination with the non-permeable solvent. The penetration is controlled to obtain stable performance of the antistatic layer using the composition.

When the osmotic solvent is used in combination with the non-permeable solvent, it is preferred that the mass ratio is a permeable solvent: a non-permeable solvent = 100:0 to 50:50, preferably 90:10 to 50:50. Further, it is 30 to 500 parts by mass based on 100 parts by mass of the total solid content of the composition for an antistatic layer.

(polymerization initiator)

The polymerization initiator is a component which starts or promotes the crosslinking reaction of the above-mentioned binder component (B), and if necessary, a conventionally known radical and cationic polymerization initiator or the like can be appropriately selected and used. As the radical polymerization initiator, for example, Irgacure 184 (1-hydroxy-cyclohexyl-phenyl-ketone) manufactured by Ciba Japan Co., Ltd. can be preferably used. In the case of using a polymerization initiator, the content thereof is preferably from 0.4 to 2.0% by mass based on the total mass of the total solid content of the antistatic layer composition. The antistatic layer can be made by setting the amount of the polymerization initiator used in the composition for an antistatic layer to 1/10 to 1/2 of the amount of the polymerization initiator used in the HC layer as described above. The reactive groups remain in large amounts. Thereby, the reaction is difficult to carry out, so that the occurrence of curling is also prevented.

(Preparation of a curable resin composition for an antistatic layer)

The curable resin composition for an antistatic layer can be obtained by mixing and dispersing the above components (A), (B) and (C) in a solvent. Further, even if the component (A), (B) or (C) has sufficient fluidity even in the absence of a solvent, it may be solvent free. As the mixed dispersion, a known method such as a paint shaker or a bead mill can be used.

In the curable resin composition for an antistatic layer of the present invention, the antistatic agent (A) is in the above range, and the film thickness of the curable resin composition for an antistatic layer may be 1 to 5 μm. The surface resistance of the cured product is less than 1 × 10 ¹² Ω / □. By making the antistatic layer such an antistatic property, even if the HC layer having a relatively thick film thickness is laminated, excellent dust adhesion preventing performance can be exhibited in the entire optical film.

When the film thickness of the antistatic layer is less than 1 μm, it is necessary to increase the amount of the quaternary ammonium salt as the antistatic agent in order to maintain the same surface resistance. However, in this case, the reactive group of the antistatic agent is reduced and resistant. The possibility that the adhesion between the electrostatic layer and the HC layer deteriorates.

When the film thickness of the antistatic layer exceeds 5 μm, the surface resistance is likely to be expressed, but there is a possibility that curling occurs, the cost increases, and the handleability deteriorates.

Further, in the composition for an antistatic layer, the total amount of the antistatic agent (A) relative to the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) is 5 to 20% by mass, and the total amount of the urethane urethane (C) relative to the polyfunctional monomer (B) and the urethane acrylate (C) is 5 to 30% by mass, in addition to being sufficiently obtained. In addition to the antistatic property, excellent durability of the optical film to ultraviolet rays (UV) can be obtained.

(optical film)

The optical film of the present invention is one surface side of a cellulose triacetate substrate, and an antistatic layer and a hard coat layer having a film thickness of 1 to 5 μm are provided adjacent to each other from the side of the cellulose triacetate substrate. The antistatic layer includes a cured product of the curable resin composition for an antistatic layer, and the polyfunctional monomer (B) penetrates into a region on the interface side of the antistatic layer side of the triacetylcellulose substrate. hardening.

The antistatic layer having a film thickness of 1 to 5 μm and the optical film of the HC layer are provided on the surface side of the TAC substrate from the side of the TAC substrate, and the curable resin composition for the antistatic layer is contained in the antistatic layer. The cured product can still have sufficient dust adhesion prevention property and is excellent in adhesion between the HC layer and the antistatic layer. Further, by allowing the polyfunctional monomer (B) to permeate into the region on the interface side of the antistatic layer side of the TAC substrate and hardening, adhesion between the antistatic layer and the TAC substrate can be obtained. As the entire optical film, excellent dust adhesion prevention performance can be obtained.

In a preferred embodiment of the optical film of the present invention, the antistatic layer may be formed of a cured product of the antistatic layer composition, or the hard coat layer of the optical film, the antistatic layer, and the triacetate may be used. The adhesion ratio of the cell adhesion test between the cellulose substrates is 90 to 100%, and after irradiating the ultraviolet rays for 192 hours at a temperature of 30 ° C and a humidity of 40% at an amount of 500 W/m ² per hour (hereinafter, there are The adhesion rate, which is simply referred to as "after UV (Ultraviolet) test), is 80 to 100%.

The adhesion ratio indicates the adhesion between the HC layer, the antistatic layer, and the TAC substrate, that is, the adhesion between the antistatic layer and the HC layer, and the adhesion between the antistatic layer and the TAC substrate.

It is conventionally known that it does not contain an urethane acrylate (C), mainly contains only a polyfunctional monomer (B) as a binder, or even contains an urethane acrylate (C). An antistatic layer and a TAC substrate in an optical film comprising an antistatic layer composed of a cured product of an antistatic agent (A), a polyfunctional monomer (B), and a composition of an urethane urethane (C) Although the adhesion between the two is good, the adhesion between the antistatic layer and the HC layer is not sufficient. When the adhesion between the antistatic layer and the HC layer is insufficient, if the adhesion test is performed, the antistatic layer and the TAC substrate are not peeled off, but an antistatic layer and the HC layer are generated. Peel off and peel off. When the adhesion between the antistatic layer and the TAC substrate is insufficient, peeling and peeling may occur between the antistatic layer and the TAC substrate. Therefore, in order to obtain excellent adhesion as an optical film, adhesion between the antistatic layer and the HC layer and adhesion between the antistatic layer and the TAC substrate are required.

The antistatic layer is cured to form an antistatic layer, and the antistatic layer having a thickness of 1 to 5 μm is in close contact with the HC layer and the adhesion between the antistatic layer and the TAC substrate is excellent, and the entire optical film is formed. Excellent adhesion. In particular, the adhesion is more remarkable after the UV resistance test. The optical film of the present invention also exhibits excellent adhesion after the UV resistance test.

Fig. 1 is a schematic view showing an example of a layer configuration of an optical film of the present invention. On one side of the triacetylcellulose substrate 10, an antistatic layer 20 and a hard coat layer 30 are provided adjacent to each other in this order. Fig. 2 is a schematic view showing another example of the layer constitution of the optical film of the present invention. A low refractive index layer 40 is further provided on the hard coat layer of the optical film similar to that of FIG.

In the following, a triacetate substrate, an antistatic layer, and a hard coat layer, which are essential components of the optical film of the present invention, and a high refractive index layer, a medium refractive index layer, and a low refractive index layer which are appropriately provided as needed Other layers such as an anti-glare layer and an anti-fouling layer are described.

(triacetate cellulose substrate)

The cellulose triacetate substrate used in the present invention is a cellulose triacetate film having high light transmittance, and is not particularly limited as long as it satisfies the physical properties of a light-transmitting substrate which can be used as an optical film. A TAC substrate using a previously known hard coat film or optical film can be suitably selected.

The average light transmittance of the TAC substrate in the visible light region of 380 to 780 nm is preferably 80% or more, and particularly preferably 90% or more. Further, the measurement of the light transmittance is a value measured at room temperature or in the atmosphere using an ultraviolet-visible spectrophotometer (for example, trade name UV-3100PC manufactured by Shimadzu Corporation).

The TAC substrate may be subjected to a saponification treatment or a surface treatment such as an undercoat layer. Further, an additive such as an antistatic agent may be added.

The thickness of the TAC substrate is not particularly limited, but is usually 30 to 200 μm, preferably 40 to 200 μm.

(antistatic layer)

The antistatic layer of the present invention is composed of a cured product of the curable resin composition for an antistatic layer, and has a film thickness of 1 to 5 μm. When the film thickness is thinner than 1 μm, sufficient antistatic performance cannot be obtained, and an adhesive necessary for ensuring adhesion to other layers cannot be sufficiently added. When the thickness is more than 5 μm, the antistatic agent does not exhibit the performance in a layer, and the performance of the antistatic layer is increased. Therefore, the workability is deteriorated, and if the film thickness is further increased, the film thickness is further increased. The amount of the antistatic agent or the like contained therein increases, and the cost increases.

As the performance of the antistatic layer, the surface resistance is preferably less than 1 × 10 ¹² Ω / □, more preferably 1 × 10 ¹¹ Ω / □ or less, and further preferably 1 × 10 ¹⁰ Ω / □ or less. As long as the surface resistance of the antistatic layer is good, the dust adhesion prevention property of the optical film in which the HC layer is laminated can be further improved.

(hard coating)

The hard coat layer is a layer having a hardness of "H" or more in a pencil hardness test (4.9 N load) prescribed in JIS K5600-5-4 (1999), and imparts hardness to the optical film of the present invention.

The HC layer contains a cured product of a composition for a hard coat layer, and may be a previously known hard coat layer or a hardened material containing a composition for a hard coat layer containing only a binder component, or may be a composition. The polymerization initiator and the like listed in the composition for an antistatic layer are contained therein. In order to increase the hardness of the HC layer, etc., it is also possible to contain a component which has been previously known to impart hardness. For example, a reactive cerium oxide microparticle having cross-linking reactivity with a binder component described in JP-A-2008-165040.

As a specific example, a resin composition containing an ionizing radiation curable resin as a transparent resin can be applied onto a transparent substrate, and the monomers, oligomers, and prepolymers contained in the resin composition can be mixed. The HC layer is formed by polymerization and/or polymerization.

The transparent resin is preferably an ionizing radiation curable resin, and the functional group of the monomer, the oligomer, and the prepolymer is preferably a functional group for ionizing radiation polymerization, and among them, a photopolymerizable functional group is preferable. By bonding the functional group to the reactive group of the urethane urethane (C) in the resin composition for an antistatic layer, sufficient adhesion between the antistatic layer and the HC layer can be obtained.

Examples of the photopolymerizable functional group include an unsaturated polymerizable functional group such as a (meth)acryl fluorenyl group, a vinyl group, a styryl group, and an allyl group.

Further, examples of the prepolymer and the oligomer include acrylates such as (meth)acrylic acid urethane, polyester (meth) acrylate, and epoxy (meth) acrylate, and unsaturated polyesters. Epoxy resin, etc.

Examples of the monomer include styrene monomers such as styrene and α-methylstyrene, methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and pentaerythritol (meth)acrylate. , pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxy tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate , trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tris(meth)acrylate, glyceryl propoxy triacrylate, di-trimethylolpropane tetraacrylate, poly Ethylene glycol di(meth)acrylate, EO modified di(meth)acrylate of bisphenol F, EO modified di(meth)acrylate of bisphenol A, EO modified by octadecyl cyanate (Meth) acrylate, isomeric cyanuric acid EO modified tri(meth) acrylate, polypropylene glycol di(meth) acrylate, trimethylolpropane PO modified tri(meth) acrylate, three Hydroxymethylpropane EO modified tris(meth)acrylate, di-trimethylolpropane tetra(meth)acrylate, etc., acrylic acid monomer, trishydroxymethylpropane a polyhydric alcohol compound having two or more thiol groups in a molecule such as trithioglycolate, trimethylolpropane trithiopropanolate or pentaerythritol tetrathioethylene, and having two or more unsaturated bonds (meth)acrylic acid urethane or polyester (meth) acrylate or the like.

In particular, from the viewpoint of increasing the crosslinking density and obtaining the damage resistance, a polyfunctional acrylate monomer is preferred, wherein pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol The (meth) acrylate and dipentaerythritol penta (meth) acrylate are more excellent in adhesion to the antistatic layer and good in pencil hardness. Further, by mixing an oligomer component such as a urethane polyfunctional acrylate with the monomers, the hardness can be improved, the polymerization shrinkage can be reduced, and the performance of preventing curling or cracking can be favorably formed. good.

In the resin composition, inorganic fine particles such as cerium oxide may be contained in order to increase the hardness. Further, in order to improve the compatibility with the resin composition, it may be subjected to an organic surface treatment or may have a reactive group.

Further, as the binder, a polymer may be added to the above resin composition and used. Examples of the polymer include polymethyl methacrylate (PMMA), and cellulose acylate (CAP, Cellulose Acetate Propionate). By adding a polymer, the viscosity of the coating liquid can be adjusted, thereby having the advantage of facilitating coating.

Further, a photoradical polymerization initiator may be added to the above resin composition as needed. The total amount of the added amount is preferably 0.8 to 8.0% by mass based on the total mass of the total solid content of the resin composition. As a photoradical polymerization initiator, acetophenones, benzoin, diphenyl ketones, phosphine oxides, ketals, anthracenes, 9-oxosulfuric acid can be used. Classes, azo compounds, and the like.

Examples of the acetophenones include 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, and 1-hydroxy-dimethylphenyl ketone. , 1-hydroxy-dimethyl-p-isopropylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2- phenylpropiophenone, 2-benzyl-2 - dimethylamino-1-(4- phenylphenyl)-butanone, 4-phenoxydichloroacetophenone, 4-tert-butyl-dichloroacetophenone, etc., as benzoin The benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl dimethyl ketal, benzoin benzene sulfonate, benzoin tosylate, etc. .

Further, as the diphenyl ketone, diphenyl ketone, hydroxy diphenyl ketone, 4-benzylidene-4'-methyldiphenyl sulfide, 2,4-dichlorodiphenyl ketone can be used. , 4,4-dichlorodiphenyl ketone and p-chlorodiphenyl ketone, 4,4'-dimethylaminodiphenyl ketone (Michechone), 3,3',4,4'- Tetrakis(t-butylperoxycarbonyl)diphenyl ketone and the like.

Further, a photosensitizer may be used in combination, and specific examples thereof include n-butylamine, triethylamine, and poly-n-butylphosphine.

The film thickness of the HC layer may be appropriately adjusted, and may be, for example, 1 to 20 μm. It is preferably 5 to 15 μm. When it exceeds 15 μm, excellent dust adhesion preventing performance cannot be obtained, and if it is less than 5 μm, the hardness becomes insufficient and the adhesion is also weak.

In general, if the HC layer laminated on the antistatic layer is thick, the dust adhesion preventing performance is deteriorated, but if it is the composition and composition of the present invention, excellent dust adhesion preventing performance can be obtained.

In a preferred embodiment of the optical film of the present invention, even if a thick layer of HC is laminated on the antistatic layer such that the antistatic layer is 1 to 5 μm and the HC layer is 5 to 15 μm, the optical film can be sufficiently obtained. Dust adhesion prevention performance, and sufficient adhesion between the antistatic layer and the HC layer.

(other layers)

In the optical film of the present invention, in the range of the opposite side of the HC layer from the antistatic layer, the antireflection, anti-glare and anti-reflection of the optical film may be improved in the range of the present invention. Other layers such as a high refractive index layer, a medium refractive index layer, a low refractive index layer, an antiglare layer, and an antifouling layer are provided for staining or the like.

(high refractive index layer and medium refractive index layer)

The high refractive index layer and the medium refractive index layer are layers provided to adjust the reflectance of the optical film of the present invention. In the case where the high refractive index layer is provided, although not shown, it is usually provided adjacent to the TAC substrate side of the low refractive index layer. Further, in the case where the medium refractive index layer is provided, although not shown, the medium refractive index layer, the high refractive index layer, and the low refractive index layer are usually provided in this order from the TAC substrate side.

The high refractive index layer and the medium refractive index layer include a cured product mainly containing a binder component and a composition for refractive index adjusting particles. As the binder component, a polyfunctional monomer or the like exemplified as the composition for an antistatic layer can be used. Examples of the particles for adjusting the refractive index include fine particles having a particle diameter of 100 nm or less. Examples of such fine particles include zinc oxide (refractive index: 1.90), titanium dioxide (refractive index: 2.3 to 2.7), cerium oxide (refractive index: 1.95), tin-doped indium oxide (refractive index: 1.95), and doping. One or more of the group consisting of antimony tin oxide (refractive index: 1.80), cerium oxide (refractive index: 1.87), and zirconia (refractive index: 2.0).

Specifically, the refractive index of the high refractive index layer is preferably from 1.50 to 2.80. The refractive index of the medium refractive index layer is lower than the refractive index of the high refractive index layer, preferably 1.50 to 2.00.

The film thickness of the high refractive index layer and the medium refractive index layer may be appropriately adjusted, and is preferably 50 to 300 nm.

(low refractive index layer)

The low refractive index layer contains a composition containing a component having a low refractive index such as cerium oxide or magnesium fluoride and a binder component, or a composition for a low refractive index layer containing a fluorine-containing resin such as a vinylidene fluoride copolymer. A previously known low refractive index layer can be formed.

In the composition for forming the low refractive index layer, hollow particles may be contained in order to lower the refractive index of the low refractive index layer. Hollow particles refer to particles having an outer shell layer and surrounded by an outer shell layer, which are porous structures or voids. The porous structure or cavity contains air (refractive index: 1), and by making the low refractive index layer contain hollow particles having a refractive index of 1.20 to 1.45, the refractive index of the low refractive index layer can be lowered. The average particle diameter of the hollow particles is preferably from 1 to 100 nm. As the hollow particles, those of the conventionally known low refractive index layer can be used, and for example, fine particles having voids as described in JP-A-2008-165040 can be used.

When the number average primary particle diameter of the fatty acid metal salt particles is less than the lower limit, there are cases in which aggregation of fatty acid metal salt particles or aggregation of the fatty acid metal salt particles with the colored resin particles is likely to occur. The printing performance of toner has an adverse effect.

On the other hand, when the number average primary particle diameter of the above-mentioned fatty acid metal salt particles exceeds the above upper limit, there is a case where the fatty acid metal salt particles are easily released (disengaged) from the colored resin particles, and it is impossible to add the desired additives. The function (the function of imparting charge stability and fluidity to the toner) is sufficiently imparted to the toner particles, which adversely affects the printing performance of the toner.

(anti-glare layer)

The antiglare layer contains a cured product of a composition for an antiglare layer containing a binder component and an antiglare agent, and the binder component may be a polyfunctional monomer or the like exemplified for the composition for an antistatic layer.

Examples of the antiglare agent include fine particles, and examples thereof include styrene particles (refractive index: 1.59), melamine particles (refractive index: 1.57), and acrylic particles (refractive index: 1.49). The average particle diameter of such fine particles imparting anti-glare property is preferably from 100 to 500 nm. The content of the fine particles to which the anti-glare property is applied is preferably 2 to 30% by mass based on the total mass of the binder component contained in the composition for an anti-glare layer.

(anti-fouling layer)

According to a preferred aspect of the present invention, in order to prevent stains on the outermost surface of the optical film, an antifouling layer may be provided on the outermost surface of the optical film opposite to the TAC substrate. By the antifouling layer, the optical film can be further improved in antifouling properties and scratch resistance. The antifouling layer contains a cured product of an antifouling layer composition containing an antifouling agent and a binder component.

As the binder component of the composition for an antifouling layer, a conventionally known one can be used. For example, a polyfunctional monomer exemplified as the composition for an antistatic layer can be used.

The antifouling agent to be contained in the antifouling layer composition can be appropriately selected from one or two or more kinds selected from the known antifouling agents such as a leveling agent. The content of the antifouling agent is preferably from 0.1 to 5% by mass based on the total mass of the binder component contained in the antifouling layer composition.

(Method of manufacturing optical film)

The method for producing the optical film of the present invention is not particularly limited as long as it is a layer forming the optical film, and a conventionally known method can be used.

As an example, the method includes the steps of: (i) preparing a cellulose triacetate substrate; (ii) preparing the composition for an antistatic layer and a composition for a hard coat layer; and (iii) coating the surface of the TAC substrate The antistatic layer composition is used to form a coating film; (iv) the coating film of the antistatic layer composition is irradiated with light to be hardened to form an antistatic layer; (v) coated on the antistatic layer. The hard coat layer is formed into a coating film by the composition; (vi) the coating film of the composition for the HC layer is irradiated with light to be hardened to form an HC layer.

Further, in the above step (iv), the coating film of the composition for an antistatic layer may not be completely cured, but half cured, and coated on the semi-hardened coating film. The HC layer was coated with a composition to form a coating film, and the semi-cured coating film was combined with the coating film of the HC layer composition, and then subjected to light irradiation, and then completely cured to obtain an optical film. By using the semi-hardening method as described above, there is an advantage that the adhesion between the antistatic layer and the HC layer is improved.

The coating method is not particularly limited as long as it is a conventionally known method, and a gravure coating method, a spin coating method, a dipping method, a spray method, a swash plate coating method, a bar coating method, a roll coating method, and a meniscus can be used. Various methods such as a face coating method, a quick-drying printing method, a screen printing method, and a droplet coating method.

Light irradiation mainly uses ultraviolet rays, visible light, electron beams or ionizing radiation. In the case of ultraviolet curing, ultraviolet rays emitted from light such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a xenon arc lamp, a metal halide lamp, or the like are used. The amount of irradiation of the energy ray source is 50 to 500 mJ/cm ^{2 in terms} of the cumulative exposure amount at an ultraviolet wavelength of 365 nm. In the case of semi-hardening, the irradiation amount is 5 to 50 mJ/cm ² . In the case of heating in addition to light irradiation, it is usually treated at a temperature of 40 ° C to 120 ° C.

After the composition for the antistatic layer is applied and before the light irradiation, it may be dried. Examples of the drying method include a method of drying under reduced pressure, heating and drying, and further drying. Further, in the case of drying at normal pressure, drying is preferably carried out at 30 to 110 °C. For example, when methyl ethyl ketone is used as a solvent for the composition for an antistatic layer, it can be carried out at a temperature of from room temperature to 80 ° C, preferably from 40 ° C to 70 ° C for 20 seconds to 3 seconds. A drying step of from minute to minute, preferably from 30 seconds to 1 minute.

The composition of the HC layer or the low refractive index layer or the like may be prepared in the same manner as the above antistatic layer. Further, when a low refractive index layer or the like is provided on the HC layer, the above-described antistatic layer coating method or curing method can be used.

(polarizer)

The polarizing plate of the present invention is characterized in that a polarizer is provided on the side of the cellulose triacetate substrate of the optical film. Fig. 3 is a schematic view showing an example of a layer configuration of a polarizing plate of the present invention. The polarizing plate 80 shown in FIG. 3 has an optical film 1 and a polarizing plate 70 in which a protective film 50 and a polarizing layer 60 are laminated, and the polarizing plate 70 is provided on the side of the cellulose acetate substrate 10 of the optical film 1.

Further, a polarizing plate is disposed on the triacetate substrate side of the optical film, and includes not only the case where the optical film and the polarizer are independently formed, but also the member constituting the optical film as a member constituting the polarizer.

Further, when the polarizing plate of the present invention is used for a display panel, the display panel is usually disposed on the side of the polarizer.

In addition, as for the optical film, the above-mentioned optical film can be used, and the description herein is omitted. Hereinafter, other configurations of the polarizing plate of the present invention will be described.

(polarizer)

The polarizer used in the present invention is not particularly limited as long as it has a predetermined polarizing property, and a polarizer generally used in a liquid crystal display device can be used.

The form of the polarizer is not particularly limited as long as it can maintain a predetermined polarizing characteristic for a long period of time. For example, it may be composed only of a polarizing layer, or may be a film or a polarizing layer. When the protective film is bonded to the polarizing layer, the protective film may be formed only on one surface of the polarizing layer, or the protective film may be formed on both surfaces of the polarizing layer.

As the polarizing layer, a compound in which a mixture of polyvinyl alcohol and iodine is formed by impregnating iodine with a film containing polyvinyl alcohol and uniaxially stretching it is usually used.

Further, the protective film is not particularly limited as long as it can protect the polarizing layer and has a desired light transmittance. The light transmittance in the visible light region is preferably 80% or more, and more preferably 90% or more, as the light transmittance of the protective film. Further, the transmittance of the protective film can be measured by JIS K7361-1 (Testing Method for Total Light Transmittance of Plastic-Transparent Material).

Examples of the resin constituting the protective film include a cellulose derivative, a cycloolefin resin, polymethyl methacrylate, polyvinyl alcohol, polyimide, polyarylate, and polyethylene terephthalate. Among them, a cellulose derivative or a cycloolefin resin is preferably used.

The protective film may be a single layer or a plurality of layers. Further, in the case where the protective film is a laminate having a plurality of layers, a plurality of layers having the same composition may be laminated, or a plurality of layers having different compositions may be laminated.

Further, the thickness of the protective film can be such that the flexibility of the polarizing plate of the present invention is within a desired range and the size of the polarizer can be changed within a predetermined range by bonding to the polarizing layer. The range is not particularly limited, but is preferably in the range of 5 to 200 μm, particularly preferably in the range of 15 to 150 μm, and more preferably in the range of 30 to 100 μm. When the thickness is thinner than 5 μm, there is a possibility that the dimensional change of the polarizing plate of the present invention becomes large. Moreover, when the thickness is thicker than 200 μm, for example, when the polarizing plate of the present invention is cut, there is a possibility that the machining scrap increases or the wear of the cutting scissors becomes faster.

The protective film may be of phase difference. By using a protective film having phase difference, there is an advantage that the polarizing plate of the present invention can be made to have a viewing angle compensation function of a display panel.

The protective film has a phase difference, and is not particularly limited as long as it exhibits a desired phase difference. As such an aspect, for example, the protective film has a configuration including a single layer, and includes an optical property developing agent exhibiting phase difference, thereby having a phase difference property; and having a resin containing the above-mentioned resin The protective film is laminated with a phase difference layer containing a compound having refractive index anisotropy, and has a phase difference. In the present invention, any of these aspects can be preferably used.

(display panel)

The display panel of the present invention is characterized in that a display is disposed on the cellulose acetate substrate side of the optical film.

Examples of the display include an LCD, a PDP, an ELD (Electroluminescent Display) (organic EL, inorganic EL), a CRT, a touch panel, an electronic paper, and a tablet personal computer.

The display panel of the present invention can also be used for a touch panel, an electronic paper, a tablet PC, and the like.

An LCD-based transmission type, which is a representative example of the display, is provided with a transmissive display body and a light source device that is irradiated from the back surface. In the case where the display is an LCD, the optical film of the present invention or the polarizing plate including the optical film is disposed on the surface of the transparent display.

A PDP which is another example of the above display includes a front glass substrate and a back glass substrate which is disposed to face the front glass substrate and is filled with a discharge gas therebetween. When the display is a PDP, the optical film is provided on the surface of the surface glass substrate or the front panel (glass substrate or film substrate).

The display may be an ELD device that vapor-deposits an illuminant such as zinc sulfide or a diamine substance that emits light when a voltage is applied to a glass substrate, controls the voltage applied to the substrate, or converts the electric signal into light. A display such as a CRT that produces an image visible to the human eye. In this case, the optical film is provided on the surface of the ELD device or the CRT or the front surface of the front panel.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples. The invention is not limited by the description.

The composition 1 for an antistatic layer and the composition 1 for an HC layer having the following composition were prepared.

(Antistatic layer composition 1)

Antistatic agent (A): The product name UV-ASHC-01 manufactured by Nippon Kasei Co., Ltd. (weight average molecular weight is 20000, solid content is 70%, and quaternary ammonium salt component is 15% in solid content): solid content conversion 1 part by mass

Polyfunctional monomer (B): dipentaerythritol hexaacrylate (DPHA) (trade name: KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd., 6-functional, molecular weight 578): 64 parts by mass

Amino acrylate (C): Trade name BS577 (6-functional, weight average molecular weight: 1000) manufactured by Arakawa Chemical Industry Co., Ltd.: 35 parts by mass

Polymerization initiator: trade name Irgacure 184 (1-hydroxycyclohexyl phenyl ketone) manufactured by Ciba Specialty Chemicals Co., Ltd.: 1 part by mass

Methyl ethyl ketone: 100 parts by mass

(Composition for HC layer 1)

Dipentaerythritol hexaacrylate (trade name: KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd., 6-functional, molecular weight 578): 98 parts by mass

Polymerization initiator: trade name Irgacure 184 (1-hydroxycyclohexyl phenyl ketone) manufactured by Ciba Specialty Chemicals Co., Ltd.: 4 parts by mass

Methyl ethyl ketone: 100 parts by mass

(Example 1)

A TAC substrate (trade name: TF80UL, manufactured by Fuji Film Co., Ltd.) having a thickness of 80 μm was prepared, and the prepared antistatic layer composition 1 was applied to one surface of the TAC substrate at a temperature of 70 ° C. The film was dried in a hot oven for 60 seconds to evaporate the solvent in the coating film, and then the coating film was cured by irradiating ultraviolet rays so as to have an integrated light amount of 50 mJ, thereby forming an antistatic layer having a thickness of 2.5 μm at the time of drying.

Then, the composition 1 for the hard coat layer prepared by applying the obtained antistatic layer is dried in the same manner as the antistatic layer, and then the ultraviolet light is irradiated so that the cumulative amount of light reaches 150 mJ to cure the coating film. A hard coat layer having a thickness of 12 μm at the time of drying was formed, whereby an optical film having an antistatic layer and a hard coat layer in this order from the side of the TAC substrate on one side of the TAC substrate was prepared.

Further, in order to measure the surface resistance value of the antistatic layer, the step of forming the antistatic layer on the TAC substrate (TF80UL) was carried out in the same manner as the above optical film, and it was also made to have only one side on the side of the TAC substrate. A layered body of an electrostatic layer.

(Examples 2 to 7)

In the first embodiment, the amounts or types of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) contained in the composition 1 for an antistatic layer are as shown in Table 1. An optical film and a laminate were produced in the same manner as in Example 1 except that the above was replaced. Further, the urethane urethane (C) used in Example 7 is a trade name of UV-7610B (manufactured by Nippon Synthetic Co., Ltd.).

(Comparative Examples 1, 2)

In the first embodiment, the amounts of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) contained in the composition 1 for an antistatic layer are as shown in Table 1. An optical film and a laminate were produced in the same manner as in Example 1 except that the procedure was replaced.

(Comparative Example 3)

In the first embodiment, R128H (monofunctional, molecular weight 222) manufactured by Nippon Kayaku Co., Ltd. is used as the polyfunctional monomer (B) contained in the composition 1 for the antistatic layer, and Opticals were produced in the same manner as in Example 1 except that the amounts of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) were replaced as shown in Table 1, respectively. Film and laminate.

(Comparative Example 4)

In the first embodiment, as the polyfunctional monomer (B) contained in the composition 1 for an antistatic layer, DPCA60 (6-functional, molecular weight 1263) manufactured by Nippon Kayaku Co., Ltd. is used instead of DPHA, and Opticals were produced in the same manner as in Example 1 except that the amounts of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) were replaced as shown in Table 1, respectively. Film and laminate.

(Comparative Example 5)

In Example 1, as the urethane urethane (C) contained in the composition 1 for an antistatic layer, EBECRYL 270 (bifunctional, molecular weight 1500) manufactured by Daicel-Cytec Co., Ltd. was used instead of BS577. The amounts of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) were replaced as shown in Table 1, except that the same manner as in Example 1 was carried out. Production of optical films and laminates.

(Comparative Example 6)

In Example 1, as the urethane urethane (C) contained in the composition 1 for an antistatic layer, EBECRYL 5129 (6-functional, molecular weight: 800) manufactured by Daicel-Cytec Co., Ltd. was used instead of BS577. The amounts of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) were replaced as shown in Table 1, except that the same manner as in Example 1 was carried out. Production of optical films and laminates.

(Comparative Example 7)

In the first embodiment, as the urethane urethane (C) contained in the composition 1 for the antistatic layer, BS371MLV (50-functional, molecular weight: 20000) manufactured by Arakawa Chemical Industry Co., Ltd. was used instead of BS577. The amounts of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) were replaced as shown in Table 1, except that the same manner as in Example 1 was carried out. Production of optical films and laminates.

(Comparative Examples 8 to 11)

In the first embodiment, the amounts of the antistatic agent (A), the polyfunctional monomer (B), and the urethane acrylate (C) contained in the composition 1 for an antistatic layer are as shown in Table 1. An optical film and a laminate were produced in the same manner as in Example 1 except that the procedure was replaced.

(Reference example 1)

An optical film and a laminate were produced in the same manner as in Example 6 except that the solvent contained in the composition for the antistatic layer 1 was replaced with a solvent other than the non-permeable solvent.

(Comparative Example 12)

In Example 3, the urethane urethane (C) contained in the composition 1 for an antistatic layer was replaced with caprolactone-modified dipentaerythritol hexaacrylate (trade name: KAYARAD DPCA-60, Nippon Kasei) An optical film and a laminate were produced in the same manner as in Example 3 except for the production of a drug. This compound tends to be hydrophilic for the same reason as DPHA.

(Reference example 2)

In the third embodiment, the antistatic agent (A) contained in the composition 1 for an antistatic layer is replaced with an antistatic agent (B) (metal microparticles: ATO, trade name: ELCOM V3560, manufactured by a daily wave catalyst) An optical film and a laminate were produced in the same manner as in Example 3 except for the above.

(Reference Example 3)

In the same manner as in Reference Example 2, an optical film was produced in the same manner as in Reference Example 2, except that the amount of the antistatic agent (B) contained in the composition for antistatic layer 1 was increased as shown in Table 1. Laminated body.

(Evaluation of surface resistance value of antistatic layer)

The laminate of the antistatic layer was laminated on the substrates of Examples 1 to 7, Comparative Examples 1 to 12, and Reference Examples 1 to 3, and a high resistivity meter (trade name Hiresta IP manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was used. MCP-HT260) The surface resistance value was measured at an applied voltage of 1000V. The results are shown in Table 1. In addition, the unit Ω/□ of the surface resistance value described in the present invention means Ω/sq. (resistance per unit area).

(Evaluation of dust adhesion prevention of optical film)

The HC layer of the optical layered product comprising the substrate/antistatic layer/hard coat layer produced in the examples and the comparative examples was rubbed back and forth 20 times with a polyester cloth, and then the wiping surface was brought close to the cigarette ash and evaluated on the following basis. Dust adhesion prevention.

○: The ash does not adhere, and has a dust adhesion preventing effect and is good.

×: A large amount of ash adheres, and there is no dust adhesion preventing effect.

(Evaluation of the adhesion of optical films)

The optical films of Examples 1 to 7, Comparative Examples 1 to 12, and Reference Examples 1 to 3 were conditioned at a temperature of 25 ° C and a humidity of 40% for 24 hours, and then hard coated according to the method of the grid test of JIS K5400. On the level, 11 slits were cut into and out at intervals of 1 mm to make 100 squares. After attaching the Cellotape (registered trademark) manufactured by Nichiban to the square, it was quickly stretched in the direction of 90°. This was peeled off, and the adhesion ratio was calculated based on the following criteria.

Bonding rate (%) = (number of squares without peeling off / total number of squares 100) × 100

Further, the optical films of Examples 1 to 7, Comparative Examples 1 to 12, and Reference Examples 1 to 3 were also subjected to humidity control at a temperature of 25 ° C and a humidity of 40% for 24 hours, at a temperature of 30 ° C and a humidity of 40%. The adhesion rate after irradiating ultraviolet rays for 192 hours at an amount of light of 500 W/m ² per hour. The measurement results of the adhesion ratio of the optical film before and after the UV resistance test are shown in Table 1.

(summary of results)

According to Table 1, in Examples 1 to 7, the surface resistivity of a good laminate (antistatic layer) was obtained, and the adhesion of the optical film was also good. Moreover, the optical characteristics and appearance are also good.

However, in Comparative Examples 1 and 2, since the polyfunctional monomer (B) or the urethane acrylate (C) was not contained in the composition for an antistatic layer, although the adhesion rate before the UV test was good, The adhesion rate after UV resistance test is poor.

In Comparative Example 3, since the polyfunctional monomer (B) was monofunctional, a sufficient adhesion ratio was not obtained.

In Comparative Example 4, the molecular weight of the polyfunctional monomer (B) exceeded 1,000, and the adhesion rate was low, and the adhesion ratio after the UV resistance test was low. This is considered to be because the penetration of the polyfunctional monomer (B) into the TAC substrate is insufficient, and the adhesion between the TAC substrate and the antistatic layer is insufficient.

In Comparative Example 5, the number of functional groups of the urethane acrylate (C) was 2 and less, and the adhesion rate was low, and the adhesion ratio after the UV test was particularly low. The reason for this is considered to be that the crosslinking caused by the urethane acrylate (C) is small, and the adhesion between the antistatic layer and the HC layer is insufficient.

In Comparative Example 6, the molecular weight of the urethane acrylate (C) was less than 1,000, and the adhesion ratio after the UV resistance test was low. This is considered to be because the urethane urethane (C) excessively penetrates into the TAC substrate, so that the adhesion between the antistatic layer and the HC layer is insufficient.

In Comparative Example 7, the molecular weight of the urethane acrylate (C) exceeded 10,000, and the adhesion rate was low, and the adhesion rate after the UV resistance test was low. The surface resistance value is also high, and it is considered that the reason is that the urethane urethane (C) is not completely penetrated into the TAC substrate, and the relative amount of the antistatic agent (A) in the antistatic layer is small.

In Comparative Example 8, the content ratio of the antistatic agent (A) was small, and the surface resistance value was high.

In Comparative Example 9, the antistatic agent (A) has a large content ratio and is excellent in antistatic property, but the amount of the polyfunctional monomer (B) and the urethane acrylate (C) which are binders is small. Therefore, the adhesion rate is low before and after the UV test.

In Comparative Example 10, since the content ratio of the polyfunctional monomer (B) was large, the content ratio of the urethane amide (C) was small, so that the adhesion ratio was low, and the adhesion ratio after the UV test was particularly high. low.

In Comparative Example 11, since the content ratio of the urethane amide (C) was large and the content of the polyfunctional monomer (B) was small, the adhesion rate before the UV test was good, but after the UV test. The bonding rate is low.

In Reference Example 1, the adhesion rate was low and the surface resistance value was high. The reason for this is considered to be that since the solvent in the composition for an antistatic layer is only made to be a permeation solvent, the urethane acrylate (C) is not sufficiently penetrated into the TAC substrate, and the antistatic layer in the antistatic layer is antistatic. The relative amount of the agent (A) is small.

In Comparative Example 12, since the urethane urethane (C) which is a hydrophobic resin was not used, the quaternary ammonium salt was excessively dispersed, and the surface resistance value was high. Therefore, dust adhesion prevention property is also not obtained.

In Reference Example 2, metal fine particles were used as an antistatic agent. Since the amount of addition of water (relatively small) which is the same as the case of the quaternary ammonium salt is obtained, the surface resistance value is inferior.

In Reference Example 3, in order to obtain the necessary antistatic property regardless of the total light transmittance, more metal fine particles as an antistatic agent than the reference example 2 were prepared, and thus the adhesion was inferior. When the amount of addition was large, coloring occurred, and the total light transmittance was lower than that of the quaternary ammonium salt (88%), and the haze value (0.8%) was high.

As a result of evaluating the dust adhesion preventing property of the optical films of the examples, the comparative examples, and the reference examples, the surface resistivity of the laminate was not more than 1 × 10 ¹² Ω/□, but it was good. In the case, the ash is heavily attached. In other words, in the case of an antistatic layer having a preferable surface resistance value, even if an HC layer is laminated thereon, dust adhesion prevention property can be imparted to the optical film.

1, 2. . . Optical film

10. . . Triacetyl cellulose substrate

20. . . Antistatic layer

30. . . Hard coating

40. . . Low refractive index layer

50. . . Protective film

60. . . Polarizing layer

70. . . Polarizer

80. . . Polarizer

Fig. 1 is a schematic view showing an example of a layer configuration of an optical film of the present invention.

Fig. 2 is a schematic view showing another example of the layer constitution of the optical film of the present invention.

Fig. 3 is a schematic view showing an example of a layer configuration of a polarizing plate of the present invention.

1. . . Optical film

10. . . Triacetyl cellulose substrate

20. . . Antistatic layer

30. . . Hard coating

Claims (8)

A curable resin composition for an antistatic layer, comprising: (A) an antistatic agent; (B) a polyfunctional monomer having two or more photocurable groups in one molecule and having a molecular weight of 900 or less And (C) an urethane urethane having 6 or more acryl fluorenyl groups and/or methacryl fluorenyl groups in one molecule and having a weight average molecular weight of 1000 to 11,000; the (A) relative to the The ratio of the total amount of A), (B), and (C) is 1 to 30% by mass, and the ratio of the total amount of (C) to the total of (B) and (C) is 1 to 40% by mass; The surface resistivity of the cured product having a thickness of 1 to 5 μm in the curable resin composition for an antistatic layer is less than 1 × 10 ¹² Ω/□. The curable resin composition for an antistatic layer according to the first aspect of the invention, wherein the (A) is a quaternary ammonium salt having a weight average molecular weight of from 1,000 to 50,000. The curable resin composition for an antistatic layer according to the first aspect of the invention, further comprising (D) a permeable solvent and (E) a non-permeable solvent. An optical film which is provided on one surface side of a cellulose triacetate substrate, and an antistatic layer and a hard coat layer having a film thickness of 1 to 5 μm are provided adjacent to each other from the side of the cellulose triacetate substrate, wherein The antistatic layer contains the cured product of the curable resin composition for an antistatic layer according to any one of claims 1 to 3, wherein the polyfunctional monomer (B) penetrates to the cellulose acetate substrate. Electrostatic layer The area near the side interface is hardened. The optical film of claim 4, wherein the adhesion between the hard coat layer, the antistatic layer and the cellulose triacetate substrate is 90 to 100%, and the temperature is 30. At °C and humidity of 40%, the adhesion rate after irradiation with ultraviolet light for 192 hours at a light amount of 500 W/m ² per hour was 80 to 100%. The optical film of claim 4, wherein a low refractive index layer is further provided on a surface of the hard coat layer opposite to the antistatic layer. A polarizing plate characterized in that a polarizer is provided on a side of a cellulose triacetate substrate of an optical film of the fourth aspect of the above patent application. A display panel characterized in that a display is disposed on a cellulose triacetate substrate side of an optical film of the fourth aspect of the above patent application.