KR20200135173A - Optical film and process for producing the same - Google Patents

Abstract

An objective of the present invention is to provide an optical film capable of preventing the exfoliation of a polarizer when used as a polarizing plate protection film, the deterioration of a polarizer under a moist heat endurance condition, or the deterioration of haze (especially, internal haze) and slipperiness influencing the returnability of a film, and an optical film manufacturing method. The optical film contains organic particles, and a polymer including an alicyclic hydrocarbon monomer having at least a polar group or a polymer including at least a (meth) acrylic monomer. The optical film contains a surfactant within a range of 0.01 to 1 ppm. The organic particles contain a polymer including at least a (meth) acrylic monomer. The solubility of the surfactant to ethanol at 23°C is 0.2 to 10 mass%, the solubility of the same to dichloromethane is less than 7 mass%, and also, the solubility of the same to water is no less than 7 mass%.

Description

Optical film and manufacturing method of optical film {OPTICAL FILM AND PROCESS FOR PRODUCING THE SAME}

The present invention relates to an optical film and a method of manufacturing an optical film, and in particular, peeling of the polarizer when used as a polarizing plate protective film, deterioration of the polarizer under moist heat durability conditions, slip properties and haze that affect the transportability of the film It relates to an optical film capable of preventing deterioration of (in particular, internal haze) and a method for producing an optical film.

Liquid crystal displays are widely used as display devices such as televisions, notebook computers, and smart phones. A liquid crystal display device usually includes a liquid crystal cell and a pair of polarizing plates sandwiching the liquid crystal cell; The polarizing plate includes a polarizer and a pair of protective films holding it.

Water resistance is required for such a protective film from the viewpoint of dimensional variation due to moisture absorption, humidity dependence of phase difference, and prevention of deterioration of polarizers during moist heat durability. Therefore, a cycloolefin resin film or an acrylic resin film is used as a protective film.

In addition, for the transportability and winding property of the film, adding fine particles into the film is disclosed (for example, see Patent Document 1).

For such fine particles, when inorganic fine particles are used, due to hydrophilicity, dispersion in a hydrophobic resin such as a cycloolefin resin is difficult, or the refractive index is not appropriate, so that internal haze cannot be mainly set as a target value. Therefore, it is known to use organic fine particles instead of inorganic fine particles.

For example, in the technique disclosed in Patent Document 2, a surfactant is used to produce organic fine particles by emulsion polymerization.

On the other hand, as a manufacturing method of a film, a method of performing solution casting is known from the viewpoint of the surface quality and productivity of the film, and the robustness of the formulation (solvent composition, additive).

However, the organic fine particles produced by emulsion polymerization contain a lot of surfactants, and dispersion and stabilization of such surfactants in a paint is disclosed in Patent Document 3, but a small amount is contained in the film-forming dope used for solution casting. No case is mentioned.

When preparing an optical film by forming a film of a cycloolefin resin or an acrylic resin by solution casting, when organic fine particles are added, the surfactant is unintentionally contained, so the content cannot be properly controlled, and undesirable physical properties. There is a problem that a surfactant is also contained. As a result, when the said optical film was used as a polarizing plate protective film, there existed problems, such as peeling of a polarizer, deterioration of a polarizer under moist heat durability conditions, sliding property which affects the transportability of a film, and deterioration of haze.

On the other hand, in the preparation of organic fine particles, a surfactant was indispensable in polymerizing by dispersing a monomer (monomer).

Japanese Patent Publication No. 2006-293331 Japanese Patent Publication No. 2006-233055 Japanese Patent Publication No. 2009-203378

The present invention has been made in view of the above problems and conditions, and the problem to be solved is the peeling of the polarizer when used as a polarizing plate protective film, deterioration of the polarizer under moist heat durability conditions, and sliding properties that affect the transportability of the film. It is to provide an optical film capable of preventing deterioration of haze (in particular, internal haze) and a method for producing an optical film.

In order to solve the above problems, the present inventors, in the process of examining the cause of the above problem, etc., prior to adding the organic fine particles to the dope at the time of manufacture of the optical film, prior to the treatment of removing the surfactant By doing so, it is possible to appropriately control the amount of surfactant to be introduced into the dope or optical film, thereby stabilizing the dispersibility of organic fine particles, and providing an optical film and a method of manufacturing an optical film excellent in film properties. I found out and came to the present invention.

That is, the said subject concerning this invention is solved by the following means.

1. An optical film containing organic fine particles and a polymer containing at least an alicyclic hydrocarbon monomer having a polar group or a polymer containing at least a (meth)acrylic monomer,

Contains a surfactant in the range of 0.01 to 1 ppm,

The organic fine particles contain a polymer containing at least a (meth)acrylic monomer,

Optical characterized in that the solubility in ethanol at 23°C of the surfactant is 0.2 to 10% by mass, solubility in dichloromethane is less than 7% by mass, and solubility in water is 7% by mass or more. film.

2. The optical film according to item 1, wherein the surfactant is an anionic surfactant.

3. The optical film according to item 1 or 2, wherein a difference in refractive index between the polymer containing the alicyclic hydrocarbon monomer having the polar group or the polymer containing the (meth)acrylic monomer and the organic fine particles is 0.01 or less.

4. The optical film according to any one of items 1 to 3, wherein the average particle diameter of the organic fine particles is in the range of 10 to 500 nm.

5. The optical film according to any one of items 1 to 4, wherein the content of the organic fine particles is in the range of 0.1 to 20% by mass based on the total mass of the optical film.

6. It is a manufacturing method of an optical film which manufactures the optical film in any one of Claims 1-5,

As the organic fine particles, a method for producing an optical film, wherein organic fine particles subjected to a treatment to remove a surfactant present around them are used.

7. The method for producing an optical film according to item 6, wherein organic fine particles in which the surfactant has been removed with alcohol in an emulsion after synthesis of the organic fine particles by emulsion polymerization are used.

By the means of the present invention, peeling of the polarizer when used as a protective film for a polarizing plate, deterioration of the polarizer under moist heat durability conditions, deterioration of slipperiness and haze affecting the transportability of the film (particularly, internal haze) It is possible to provide an optical film that can prevent and a method of manufacturing an optical film.

The mechanism for expressing the effect of the present invention or the mechanism of action is not clearly defined, but is estimated as follows.

When the content of the surfactant is too large in the optical film, the surfactant is oriented on the surface of the film, so that the surface state of the optical film changes and the adhesion with the polarizer decreases. And peeling of the polarizer adhesive surface easily occurs over time. Further, since the surfactant is hydrophilic, moisture tends to enter the adhesive surface with the polarizer. When moisture enters, since the polarizer is generally polyvinyl alcohol (PVA) and is weak to water, deterioration of the polarizer is liable to occur when water enters the adhesive surface under moist heat durability conditions.

In addition, when there are many surfactants carried into the dope at the time of manufacturing an optical film, since it contaminates a process of manufacturing an optical film, continuous productivity deteriorates. This is because the surfactant released during dope causes contamination. That is, the surfactant adheres to the surface of the organic fine particles to some extent, but if it is excessive, it is released from the surface of the organic fine particles, and the surfactant has a high affinity with the surface of a flexible substrate such as a metal support. This is because it becomes easy to adhere to the surface of the substrate. In addition, since the surfactant is more stable in a place where the surface energy is low, if it is present in the dope, it is because it tends to migrate to the interface between a flexible substrate such as a metal support and a film. As a result, once the surfactant adheres to the surface of a flexible substrate such as a metal support, it becomes difficult to recover again as a dope. In addition, there is a problem that it is more susceptible to contamination depending on the solubility of the surfactant in the flexible solvent. In particular, the surface active agent adheres and accumulates on the surface of a flexible substrate such as a metal support, and when this is retransferred to the film, the surface properties, uniformity (non-uniformity), and optical properties (haze) of the film are deteriorated. It will become. In this way, in order to remove the adhered and accumulated surfactant, cleaning is required after stopping the manufacturing process once, and there is a problem that the efficiency is very poor.

On the other hand, when the content of the surfactant is too small, dispersion of the organic fine particles in the dope becomes unstable, and aggregation occurs, so there is a problem that internal haze and slip properties are deteriorated.

Therefore, in the present invention, prior to adding the organic fine particles to the dope at the time of production of the optical film, by performing a treatment to remove the surfactant in advance, the amount of the surfactant carried in the dope or the optical film is appropriately controlled. can do. As a result, the dispersibility of the organic fine particles in the dope or the optical film is stable, agglomeration does not occur, and the process at the time of manufacturing the optical film is not contaminated, and an optical film and an optical film having excellent film properties are prepared. It is estimated that it can provide.

1 is a schematic diagram showing an example of a configuration of a liquid crystal display device according to the present invention.

The optical film of the present invention is an optical film containing organic fine particles, a polymer containing an alicyclic hydrocarbon monomer having at least a polar group, or a polymer containing at least a (meth)acrylic monomer, and contains a surfactant within the range of 0.01 to 1 ppm. And the organic fine particles contain a polymer containing at least a (meth)acrylic monomer, the solubility of the surfactant in ethanol at 23°C is 0.2 to 10% by mass, and the solubility in dichloromethane Is less than 7% by mass, and the solubility in water is 7% by mass or more. Since the content of the surfactant is 1 ppm or less, contamination of a flexible substrate such as a metal support can be suppressed in the case of solution casting. As a result, the transfer of contamination to the film surface can be prevented, and the quality as an optical film is improved. Further, since the content of the surfactant is 0.01 ppm or more, aggregation of the organic fine particles in the dope or film can be prevented, the dispersibility of the organic fine particles is stabilized, and the internal haze and slipperiness are improved. In addition, by making the solubility of the surfactant in ethanol, dichloromethane, and water within the above range, it is easy to control the content of the surfactant by treatment of removing the surfactant such as washing, and contamination of flexible substrates such as a metal support is prevented. This can be prevented, and the dispersibility of the organic fine particles in the dope or film is further improved.

This feature is a technical feature common to or corresponding to each of the following embodiments.

In an embodiment of the present invention, the surfactant is preferably an anionic surfactant in that it emulsifies a (meth)acrylic monomer when producing organic fine particles, and thus polymerization is easy.

In addition, it is preferable that the refractive index difference between the polymer containing the alicyclic hydrocarbon monomer having a polar group or the polymer containing the (meth)acrylic monomer and the organic fine particles is 0.01 or less in terms of suppressing the occurrence of internal haze.

It is preferable that the average particle diameter of the organic fine particles is in the range of 10 to 500 nm. If it is 500 nm or less, unevenness on the surface of the optical film can be reduced, generation of external haze can be suppressed, and if it is 10 nm or more, it is possible to prevent the slipperiness from deteriorating due to insufficient unevenness on the surface of the optical film.

In addition, it is preferable that the content of the organic fine particles is in the range of 0.1 to 20% by mass with respect to the total mass of the optical film from the viewpoint of preventing the occurrence of haze and improving the slipperiness.

The method for producing an optical film of the present invention is a method for producing an optical film containing organic fine particles, a polymer containing at least an alicyclic hydrocarbon monomer having a polar group, or a polymer containing at least a (meth)acrylic monomer, and the organic fine particles As an example, it is characterized in that organic fine particles subjected to treatment to remove surfactants present around them are used. Thereby, it is possible to appropriately control the amount of dope or surfactant to be carried into the optical film, and an optical film having excellent film properties can be manufactured without contaminating the process at the time of manufacturing the optical film.

In addition, in the emulsion after synthesis of the organic fine particles by emulsion polymerization, the use of organic fine particles in which the surfactant has been removed with alcohol is higher than in the case of water, which has a higher removal ability of the surfactant attached to the surface of the organic fine particles. desirable. In other words, the surfactant is attached to the surface of the organic fine particles as a hydrophobic group, and water acts on the hydrophilic group on the opposite side of the surfactant, whereas alcohol can also act on the hydrophobic group attached to the organic fine particles. Big.

Hereinafter, the present invention, its constituent elements, and forms and aspects for carrying out the present invention will be described. In addition, in this application, "to" is used by the meaning including the numerical value described before and after that as a lower limit and an upper limit.

[Optical film]

The optical film of the present invention is an optical film containing organic fine particles, a polymer containing an alicyclic hydrocarbon monomer having at least a polar group, or a polymer containing at least a (meth)acrylic monomer, and contains a surfactant within the range of 0.01 to 1 ppm. And the organic fine particles contain a polymer containing at least a (meth)acrylic monomer, the solubility of the surfactant in ethanol at 23°C is 0.2 to 10% by mass, and the solubility in dichloromethane Is less than 7% by mass, and the solubility in water is 7% by mass or more.

<Surfactant>

The surfactant according to the present invention is contained within the range of 0.01 to 1 ppm in the optical film. That is, the surfactant is used in the emulsion polymerization of the organic fine particles, and is contained within the range of 0.01 to 1 ppm in the optical film by appropriately selecting the removal method described later, the type of surfactant, and the like.

Examples of the surfactant include surfactants such as anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

Examples of anionic surfactants include fatty acid oils such as sodium oleate and castor oil, kali, alkyl sulfates such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkyl sulfonates. , Alkyl naphthalene sulfonate, alkanesulfonic acid salt, succinic sulfonate, dialkyl sulfosuccinate, alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene alkyl sulfate, etc. Can be lifted.

As a nonionic surfactant, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, And oxyethylene-oxypropylene block polymers.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

Examples of the amphoteric surfactant include lauryl dimethylamine oxide and phosphoric acid ester or phosphorous acid ester surfactants.

These surfactants may be used alone or in combination of two or more. Particularly, in the present invention, the anionic surfactant is preferred in that it emulsifies a (meth)acrylic monomer when producing organic fine particles, and is easily polymerized.

The solubility of the surfactant in ethanol at 23°C is in the range of 0.2 to 10% by mass, preferably 0.5 to 5% by mass. When the solubility is 0.2% by mass or more, the cleaning efficiency when washing the organic fine particles is good, and the content of the surfactant is easily controlled. When the solubility is 10% by mass or less, it is not too soluble in ethanol, and contamination of a flexible substrate such as a metal support can be prevented. That is, when the dope is dried on a flexible substrate such as a metal support, dichloromethane having a low boiling point volatilizes from the surface of the dope. Therefore, the concentration gradient of ethanol/dichloromethane in the thickness direction of the dope is possible, and the side of a flexible substrate such as a metal support becomes ethanol-rich. When the solubility of the activator in ethanol is large, the active agent is unevenly distributed in the ethanol-rich portion of the flexible substrate side such as a metal support, and thus adheres and accumulates on the flexible substrate such as a metal support, resulting in contamination. When the solubility is below the above, there is no ubiquitous distribution of the activator, and it is possible to prevent contamination of a flexible substrate such as a metal support.

The solubility of the surfactant in dichloromethane at 23° C. is less than 7% by mass, preferably 3% by mass. When the solubility is less than 7% by mass, the active agent can be removed by phase separation by dispersing the surfactant with hydrous dichloromethane. Further, it is not too soluble in dichloromethane, which is the main solvent of dope, and the dispersibility of the organic fine particles is improved.

The solubility of the surfactant in water at 23°C is 7% by mass or more, and preferably 9% by mass. When the solubility is 7% by mass or more, an emulsion can be suitably prepared during emulsion polymerization. Further, when washing the organic fine particles, the cleaning efficiency of the surfactant is improved, and the content of the surfactant is easily controlled. In order to hydrolyze a surfactant by heating and humidification, the solubility in water, that is, the surfactant affinity with water, can be decomposed by moisture adsorbed on the surface.

As described above, it is important to balance the solubility of the surfactant in ethanol, dichloromethane, and water.

In the measurement of the content of the surfactant, first, the optical film is freeze-dried and pulverized, and then ultrasonically extracted with methanol, and after centrifugation, a methanol soluble component is dried, and the mass of the dried solid is measured. Thereafter, the dried solid was dissolved in heavy methanol added with 1,4-bis(trimethylsilyl)benzene-d4 as an internal standard, and the dissolved solution was used as an NMR device: ECZ-400S (400MHz manufactured by JEOL RESONANCE). , It is measured under the following conditions, and the content of the surfactant is calculated from the strength of the proton derived from the structure of the surfactant and the strength of the internal standard.

Observation nucleus: 1H

Pulse width: 5.6 μs (45° pulse)

Pulse delay time: 15s

Measurement integration count: 64 times

The solubility of the surfactant is determined by visually dissolving it in various solvents at 23°C. Specifically, for example, with respect to 100 g of water at 23°C, 10.0 g is dissolved by gradually adding a surfactant, and when insoluble matter is observed at 10.1 g, the solubility in water is 10/(100+10)= It becomes 9.1 mass %.

<Organic fine particles>

The organic fine particles according to the present invention are used in the production of an optical film after a surfactant removal treatment is performed as described later, and have a function of imparting slipperiness to the optical film.

The organic fine particles according to the present invention are preferably particles (polymer particles) containing a polymer containing a structural unit derived from a (meth)acrylic monomer, and the organic fine particles may be in the form of rubber (rubber particles) or in a non-rubber form. May be. By setting it as rubber particles, in the case of a film containing a polymer containing a (meth)acrylic monomer that is brittle and easily cracked, flexible flexibility can be imparted.

In addition, the rubber phase in the present invention refers to a state in which, when a stress greater than the strength of a certain material is applied, remarkable elongation or shrinkage is accompanied until the material is destroyed.

It is preferable that the organic fine particles according to the present invention have a core-shell structure (multilayer structure). The core-shell structure may be a two-layer structure consisting of a core layer and a shell layer, a three-layer structure of a core layer/intermediate layer/shell layer, and three layers of a seed particle layer/core layer/shell layer. However, the shell layer refers to the outermost layer.

The content of the organic fine particles according to the present invention is preferably within the range of 0.1 to 20% by mass with respect to the total mass of the optical film, from the viewpoint that it is possible to make it an appropriate content and to achieve both haze and slipperiness.

The organic fine particles according to the present invention have a refractive index difference of 0.01 or less with a polymer containing an alicyclic hydrocarbon monomer having a polar group or a polymer containing a (meth)acrylic monomer to be described later, so that the occurrence of internal haze can be suppressed. It is preferred, and it is more preferred that it is in the range of 0 to 0.005.

As a method for satisfying the refractive index condition, the method of adjusting the unit composition ratio of each monomer of the polymer containing the alicyclic hydrocarbon monomer having the polar group or the polymer containing the (meth)acrylic monomer, and/or used for organic fine particles And a method of adjusting the composition ratio of the polymer and/or monomer to be used.

(Measurement method of refractive index difference)

First, for organic fine particles, the organic fine particles are press-molded, the average refractive index of the molded article is measured with a laser refractometer, and the value is taken as the refractive index of the organic fine particles.

Similarly, for a polymer containing an alicyclic hydrocarbon monomer having a polar group or a polymer containing a (meth)acrylic monomer, the polymer is molded, the average refractive index of the molded article is measured with a laser refractometer, and the value of the polymer is determined. Let it be the refractive index.

The difference in refractive index can be calculated by calculating the difference in the value of the refractive index of the polymer and the organic fine particles measured as described above.

In addition, in this embodiment, the refractive index means the refractive index with respect to light of a wavelength of 550 nm at 23 degreeC.

The organic fine particles according to the present invention preferably have an average particle diameter in the range of 10 to 500 nm, and more preferably in the range of 80 to 200 nm. If it is 500 nm or less, unevenness on the surface of the optical film can be reduced, generation of external haze can be suppressed, and if it is 10 nm or more, it is possible to prevent the slipperiness from deteriorating due to insufficient unevenness on the surface of the optical film.

(Measurement method of average particle diameter)

The average particle diameter can be obtained by, for example, a dynamic light scattering method using MICROTRAC UPA150 (manufactured by Nikkiso Corporation).

It is preferable that the organic fine particles are particles (polymer particles) containing a polymer containing a structural unit derived from a (meth)acrylic monomer.

Examples of (meth)acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylic (Meth)acrylic acid esters, such as a rate, are contained. Among them, methyl (meth)acrylate and ethylene glycol di(meth)acrylate are preferable. In addition, (meth)acrylic means acrylic or methacryl.

The content rate of the structural unit derived from the (meth)acrylic monomer in the polymer containing the structural unit derived from the (meth)acrylic monomer is 20 to 99% by mass with respect to the total 100% by mass of all structural units constituting the polymer It is preferable that it is, and it is more preferable that it is 30-90 mass %, and it is still more preferable that it is 50-90 mass %.

The polymer containing a structural unit derived from a (meth)acrylic monomer may further contain a structural unit derived from another monomer copolymerizable with a (meth)acrylic monomer, if necessary.

Examples of other monomers include itaconic acid diesters, maleic acid diesters, vinyl esters, olefins, styrenes, (meth)acrylamides, allyl compounds, vinyl ethers, vinyl ketones, unsaturated nitriles and unsaturated carbohydrates. Acids are included.

Examples of itaconic acid diesters include dimethyl itaconic acid, diethyl itaconic acid, dipropyl itaconic acid, and the like. Examples of maleic acid diesters include dimethyl maleate, diethyl maleate, dipropyl maleate, and the like.

Examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxyacetate, vinylphenyl acetate, vinyl benzoate, vinyl salicylate, and the like.

Examples of olefins include dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene, and the like.

Examples of styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, brom styrene, trifluoromethyl styrene , Vinyl benzoic acid methyl ester, divinylbenzene, and the like.

Examples of (meth)acrylamides include (meth)acrylamide, methyl (meth)acrylamide, ethyl (meth)acrylamide, propyl (meth)acrylamide, butyl (meth)acrylamide, tert-butyl (meth) Acrylamide, phenyl (meth)acrylamide, dimethyl (meth)acrylamide, methylenebisacrylamide, and the like.

Examples of the allyl compound include allyl acetate, allyl caproate, allyl laurate, allyl benzoate, and the like.

Examples of vinyl ethers include methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether, and the like.

Examples of vinyl ketones include methyl vinyl ketone, phenyl vinyl ketone, and methoxyethyl vinyl ketone.

Examples of unsaturated nitriles include acrylonitrile and methacrylonitrile. Examples of unsaturated carboxylic acids include (meth)acrylic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, and the like.

Among them, from the viewpoint of good affinity with a cycloolefin resin, the other monomer is preferably at least one selected from the group consisting of vinyl esters, styrenes, and olefins, and styrenes are more preferred. That is, it is more preferable that the polymer containing a structural unit derived from a (meth)acrylic monomer is a copolymer containing a structural unit derived from (meth)acrylic acid esters and a structural unit derived from styrene.

Particles (polymer particles) containing such a polymer can be produced by any method, for example, emulsion polymerization, suspension polymerization, dispersion polymerization, and seed polymerization. Among them, seed polymerization or emulsion polymerization in an aqueous medium is preferable from the viewpoint of easy obtaining polymer particles with aligned particle diameters.

As a method for producing the polymer particles, for example

ㆍSingle stage polymerization method in which a monomer mixture is dispersed in an aqueous medium and then polymerized,

ㆍA two-stage polymerization method in which a monomer is polymerized in an aqueous medium to obtain seed particles, and then the monomer mixture is absorbed into the seed particles and then polymerized.

ㆍMulti-stage polymerization method that repeats the process of producing seed particles of the two-stage polymerization method

And the like. These polymerization methods can be appropriately selected according to the desired average particle diameter of the polymer particles. In addition, the monomer for producing seed particles is not particularly limited, and all monomers for polymer particles can be used.

As an emulsifier for emulsion polymerization, surfactants such as the above-described anionic surfactant, cationic surfactant, amphoteric surfactant, and nonionic surfactant can be mentioned.

These emulsifiers may be used alone or in combination of two or more, but they are used by appropriately adjusting the selection and amount of emulsifiers in consideration of the diameter of the obtained particles and dispersion stability during polymerization.

The organic fine particles may be particles having a core-shell structure. Examples of such organic fine particles include core-shell particles having a low Tg core layer containing a homopolymer or copolymer of (meth)acrylic acid ester, and a high Tg shell layer.

It is preferable that the core-shell particles have a structure derived from a polyfunctional compound only in the central portion (core), and have a structure with high compatibility with the resin constituting the optical film in the portion surrounding the central portion (shell). Do. Accordingly, the organic fine particles can be more uniformly dispersed in the resin, and the by-product of foreign matters caused by aggregation of the organic fine particles or the like can be further suppressed.

Hereinafter, the shell portion and the core portion of the core-shell structure will be described.

<<shell part>>

The shell portion is not particularly limited as long as it has a structure having high compatibility with the resin constituting the optical film.

<<core part>>

The core portion is not particularly limited as long as it exhibits an effect of improving the flexibility of the resin constituting the optical film, and examples thereof include a structure having crosslinking. In addition, as a structure having crosslinking, it is preferable that it is a crosslinked rubber structure.

The crosslinked rubber structure refers to a structure of a rubber in which a polymer having a glass transition point in the range of -100°C to 25°C is used as a main chain, and a polyfunctional compound crosslinks the main chains to have elasticity. Examples of the crosslinked rubber structure include structures (repeated structural units) of acrylic rubber, polybutadiene rubber, and olefin rubber. Among these, acrylic rubber is preferable because it is easy to control the average particle diameter to 0.3 µm or less, and the optical properties such as transparency of the film are good when uniformly dispersed in the resin.

As the method for synthesizing the core-shell type organic fine particles, any suitable method capable of synthesizing the core-shell type organic fine particles can be adopted.

For example, by suspending or emulsion polymerization of a polymerizable monomer forming a rubbery polymer constituting the core layer, a suspension or emulsion dispersion containing rubbery polymer particles is prepared, and then a shell layer is added to the suspension or emulsion dispersion. A method of obtaining a core-shell type elastomer having a multilayered structure obtained by radical polymerization by adding a polymerizable monomer forming the constituting glassy polymer and coating the surface of the rubbery polymer particles with the glassy polymer is mentioned.

Here, the polymerizable monomer that forms the rubbery polymer and the polymerizable monomer that forms the glassy polymer may be polymerized in one step or may be polymerized in two or more steps by changing the composition ratio.

<Polymer containing an alicyclic hydrocarbon monomer having a polar group>

As a polymer containing an alicyclic hydrocarbon monomer having a polar group contained in the optical film of the present invention (also referred to as a cycloolefin-based resin having a polar group), a polymer containing a structural unit derived from a norbornene-based monomer having a polar group desirable.

Examples of the polar group include a carboxyl group, a hydroxy group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, a cyano group, a group in which these groups are bonded through a linking group such as a methylene group, a carbonyl group, an ether group, a silyl ether group, a thioether group, It includes a hydrocarbon group in which a divalent organic group having polarity such as an imino group is bonded as a linking group.

Among these, a carboxyl group, a hydroxy group, an alkoxycarbonyl group, or an allyloxycarbonyl group is preferable, and an alkoxycarbonyl group or an allyloxycarbonyl group is particularly preferable from the viewpoint of securing solubility during solution film formation.

The norbornene-based monomer having a polar group is preferably a norbornene-based monomer represented by the following formula (A-1) or (A-2).

R ¹ and R ² in the formula (A-1) each represent a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or a polar group. However, at least one of R ¹ and R ² is a polar group.

Examples of the hydrocarbon group having 1 to 5 carbon atoms include an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a butyl group.

P in formula (A-1) represents the integer of 0-2. From the viewpoint of improving the heat resistance of the optical film, it is preferable that p is 1 to 2. This is because when p is 1 to 2, the bulk density of the obtained resin becomes large and the glass transition temperature is liable to be improved.

Since the norbornene-based monomer represented by the formula (A-2) has a low molecular symmetry, it is easy to promote the diffusion motion of the resin during solvent volatilization of the cycloolefin-based resin having a polar group.

R ³ and R ⁴ in the formula (A-2) each represent a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or a polar group. However, at least one of R ³ and R ⁴ is a polar group. The polar group and the hydrocarbon group having 1 to 5 carbon atoms have the same meaning as the polar group of formula (A-1) and the hydrocarbon group having 1 to 5 carbon atoms, respectively.

P in the formula (A-2) has the same meaning as p in the formula (A-1).

Examples of the norbornene-based monomer having a polar group include the following compounds.

The content ratio of the constituent units derived from the norbornene-based monomer having a polar group is, for example, 50 mol% or more, preferably 70 mol% or more, more preferably 100 mol% with respect to the total constituent units constituting the cycloolefin resin. It can be made into %.

If the constituent units derived from the norbornene-based monomer having a polar group are included at a certain level or more, the polarity of the resin is likely to increase and the cycloolefin-based resin can be easily dissolved in a solvent, so film formation by a solution film-forming method (cast method) is more effective. It becomes easier.

In addition to the structural unit derived from a norbornene-based monomer having a polar group, the cycloolefin-based resin further includes a structural unit derived from a norbornene-based monomer having no polar group or a monomer copolymerizable with a norbornene-based monomer having a polar group, You may have it.

In the norbornene-based monomer having no polar group, in the above formula (A-1), R ¹ and R ² are each a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or a halogen atom, or the above formula In (A-2), R ³ and R ⁴ may each be a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or a halogen atom.

Examples of the norbornene-based monomer having no polar group include the following compounds.

Examples of the monomer copolymerizable with the norbornene-based monomer having a polar group include a monomer capable of ring-opening copolymerization with the norbornene-based monomer having a polar group, and a monomer capable of addition copolymerization with the norbornene-based monomer having a polar group.

Examples of the monomer capable of ring-opening copolymerization with the norbornene-based monomer having a polar group include other cycloolefin monomers such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

Examples of the monomer capable of addition copolymerization with the norbornene-based monomer having a polar group include an unsaturated double bond-containing compound, a vinyl-based cyclic hydrocarbon compound, and a (meth)acrylate. Examples of the unsaturated double bond-containing compound are olefin compounds having 2 to 12 carbon atoms (preferably 2 to 8), and examples thereof include ethylene, propylene, and butene. Examples of the vinyl-based cyclic hydrocarbon compound include vinylcyclopentene-based monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene. Examples of the (meth)acrylate include alkyl (meth)acrylates having 1 to 20 carbon atoms such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate. do.

The cycloolefin-based resin having a polar group is a homopolymer of a norbornene-based monomer represented by the formula (A-1) or (A-2) or a copolymer of another monomer therewith, for example, the following. , (1) to (3) and (5) are preferable, and (3) and (5) are more preferable.

(1) a ring-opening polymer of a norbornene-based monomer represented by formula (A-1) or (A-2)

(2) a ring-opening copolymer of a norbornene-based monomer represented by formula (A-1) or (A-2) and another monomer

(3) Hydrogenated (co)polymer of the ring-opening (co)polymer of (1) or (2) above.

(4) (co)polymer obtained by cyclization of the ring-opening (co)polymer of (1) or (2) by a Friedel Craft reaction and then hydrogenation

(5) Copolymer of a norbornene-based monomer represented by formula (A-1) or (A-2) and an unsaturated double bond-containing compound

(6) Addition type (co)polymer of norbornene-based monomer represented by formula (A-1) or (A-2) and hydrogenated (co)polymer thereof

(7) Alternating copolymer of norbornene-based monomer represented by formula (A-1) or (A-2) and methacrylate or acrylate

The cycloolefin resin having a polar group includes those having at least one of the structural units represented by the following formula (B-1) or (B-2). Among them, from the viewpoint that the glass transition temperature of the cycloolefin-based resin having a polar group is easily increased and an optical film having a high transmittance is easily obtained, a homopolymer or formula (B) containing a structural unit represented by the formula (B-2) A copolymer having a structural unit denoted by -2) and a structural unit derived from a different monomer is preferred.

X in formula (B-1) is a group represented by -CH=CH- or a group represented by -CH ₂ CH ₂ -. R ^1, R ² and p are, respectively, is the same as the formula R ^1, R ² and p of (A-1).

X in formula (B-2) is a group represented by -CH=CH- or a group represented by -CH ₂ CH ₂ -. R ³ in the formula (B-2), R ⁴ and p are, respectively, is the same as formula (A-2) of the R ^3, R ⁴ and p.

Cycloolefin resin having a polar group can be used alone or in combination of two or more.

The SP (Solubility Parameter) value of the cycloolefin-based resin having a polar group may be 16.5 to 17.5.

The SP value of the cycloolefin resin having a polar group is calculated by the Bicerano method based on a regression equation obtained by statistically analyzing the correlation between the molecular structure and the physical property values of the polymer material. Specifically, in software "Scigress Version 2.6" (manufactured by Fujitsu Corporation) installed on a commercially available personal computer, the structure of each compound is substituted, and a value calculated by the Bicerano method is adopted.

The intrinsic viscosity [?]inh of the cycloolefin resin having a polar group is, for example, 0.2 to 5 cm 3 /g, preferably 0.3 to 3 cm 3 /g, and more preferably 0.4 to 1.5 cm 3 /g. The weight average molecular weight (Mw) of the cycloolefin-based resin is, for example, 20000 to 300000, more preferably 30000 to 250000, and still more preferably 40000 to 200000. The weight average molecular weight (Mw) can be measured in terms of polystyrene by gel permeation chromatography (GPC).

When the intrinsic viscosity [?]inh and the weight average molecular weight are in the above ranges, the heat resistance, water resistance, chemical resistance, and mechanical properties of the cycloolefin-based resin having a polar group, and the molding processability as a film become good.

The glass transition temperature (Tg) of the cycloolefin resin having a polar group is usually 110°C or higher, preferably 110 to 350°C, more preferably 120 to 250°C, and particularly preferably 120 to 220°C. . The case where Tg is 110°C or higher is preferable because deformation is difficult to occur due to use under high temperature conditions or by secondary processing such as coating or printing. On the other hand, by setting Tg to 350°C or less, it is possible to avoid the case where molding processing becomes difficult, and to suppress the possibility that the resin is deteriorated due to heat during molding processing.

In addition, as for the cycloolefin resin having a polar group, a commercial product can be preferably used, and as an example of a commercial product, it is marketed under the brand names of Aton (ARTON: registered trademark) G, Aton F, Aton R and Aton RX from JSR. And you can use these.

<Polymer containing (meth)acrylic monomer>

As a polymer (also referred to as an acrylic resin) containing a (meth)acrylic monomer contained in the optical film of the present invention, for example, poly(meth)acrylic acid esters such as polymethyl methacrylate, methyl methacrylate-(meth) Acrylic acid copolymer, methyl methacrylate-(meth)acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymer, methyl (meth)acrylate-styrene copolymer (MS resin, etc.), alicyclic hydrocarbons Group-containing polymers (eg, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-(meth)acrylate norbornyl copolymer, etc.) are mentioned.

More specifically, a resin homopolymerized or copolymerized with a combination arbitrarily selected from monomers exemplified below, and post-reactions such as cyclization reaction, dehydration condensation reaction, hydrogen addition reaction, and removal of the protective functional group are performed on the resin. In resin, it has 50% or more of (meth)acrylic acid ester by weight ratio.

(Monomer type)

As the monomer, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate , (Meth) acrylate t-butyl, (meth) acrylate n-amyl, (meth) acrylate s-amyl, (meth) acrylate t-amyl, (meth) acrylate n-hexyl, (meth) acrylate 2-ethylhexyl, Isodecyl (meth)acrylate, tridecyl (meth)acrylate, cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, ( Benzyl meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl, (meth)acrylic acid 3-hydroxybutyl, (meth)acrylic acid 4-hydroxybutyl, (meth)acrylic acid 2-Methoxyethyl, (meth)acrylate 2-ethoxyethyl, (meth)acrylate phenoxyethyl, (meth)acrylate tetrahydrofurfuryl, (meth)acrylate glycidyl, (meth)acrylate β-methylglyci Dyl, (meth)acrylate β-ethylglycidyl, (meth)acrylic acid (3,4-epoxycyclohexyl)methyl, (meth)acrylate N,N-dimethylaminoethyl, α-hydroxymethyl acrylate methyl, α- (Meth)acrylic acid esters, such as ethyl hydroxymethyl acrylate, etc. are mentioned.

Isobutyl methacrylate, 2-methylbutyl methacrylate, 2-ethylbutyl methacrylate, 2-isopropylbutyl methacrylate, 2-isopropyl-4-methylbutyl methacrylate, 2,3 methacrylic acid -Dimethylbutyl, 2-methylpentyl methacrylate, 2-ethylpentyl methacrylate, 2-propylpentyl methacrylate, 2-isopropylpentyl methacrylate;

S-butyl methacrylate, 1-methylbutyl methacrylate, 1-methylpentyl methacrylate, 1,3-dimethylbutyl methacrylate, 1,2-dimethylpropyl methacrylate, 1,2- methacrylic acid Dimethylbutyl, 1,2-dimethylpentyl methacrylate, 1,2,3-trimethylbutyl methacrylate, 2-ethyl-1-methylbutyl methacrylate, 2-ethyl-1-methylpentyl methacrylate, methacrylic acid 2-ethyl-1,3-dimethylbutyl acrylate, 1-methyl-2-propylpentyl methacrylate, 2-isopropyl-1-methylpentyl methacrylate, 2-isopropyl-1,3- methacrylate Dimethylbutyl, 1-ethylpropyl methacrylate, 1-ethylbutyl methacrylate, 1-ethylpentyl methacrylate, 1-ethyl-3-methylbutyl methacrylate, 1-ethyl-2-methylpropyl methacrylate , 1-ethyl-2-methylbutyl methacrylate, 1-ethyl-2-methylpentyl methacrylate, 1-ethyl-2,3-dimethylbutyl methacrylate, 1,2-diethylbutyl methacrylate, 1,2-diethylpentyl methacrylate, 1,2-diethyl-3-methylbutyl methacrylate, 1-ethyl-2-propylpentyl methacrylate, 2-isopropyl-1-ethylpentyl methacrylate , 1-ethyl-2-isopropyl-3-methylbutyl methacrylate, 1-propylbutyl methacrylate;

1-propylpentyl methacrylate, 3-methyl-1-propylbutyl methacrylate, 1-isopropylbutyl methacrylate, 2-methyl-1-propylbutyl methacrylate, 2-methyl-1-methacrylate Propylpentyl, 2,3-dimethyl-1-propylbutyl methacrylate, 2-ethyl-1-propylbutyl methacrylate, 2-ethyl-1-propylpentyl methacrylate, 2-ethyl-3-methacrylate Methyl-1-propylbutyl, methacrylate 1,2-dipropylpentyl, methacrylate 2-isopropyl-1-propylpentyl, methacrylate 2-isopropyl-3-methyl-1-propylbutyl, methacrylic 1-isopropylpentyl acid, 1-isopropyl-3-methylbutyl methacrylate, 1-isopropyl-2-methylpropyl methacrylate, 1-isopropyl-2-methylbutyl methacrylate, 1 methacrylic acid -Isopropyl-2-methylpentyl, 1-isopropyl methacrylate-2,3-dimethylbutyl, 2-ethyl-1-isopropylbutyl methacrylate, 2-ethyl-1-isopropylpentyl methacrylate, 2-diethyl-1-isopropyl-3-methylbutyl methacrylate, 1-isopropyl-2-propylpentyl methacrylate, 1,2-diisopropylpentyl methacrylate, 1,2- methacrylic acid Isopropyl-3-methylbutyl;

T-butyl methacrylate, 1,1-dimethylpropyl methacrylate, 1-ethyl-1-methylpropyl methacrylate, 1,1-diethylpropyl methacrylate, 1,1-dimethylbutyl methacrylate, 1-ethyl-1-methylbutyl methacrylate, 1,1-diethylbutyl methacrylate, 1-methyl-1-propylbutyl methacrylate, 1-ethyl-1-propylbutyl methacrylate, methacrylic acid 1,1-dipropylbutyl, methacrylic acid 1,1,2-trimethylpropyl, methacrylic acid 1-ethyl-1,2-dimethylpropyl, methacrylic acid 1,1-diethyl-2-methylpropyl, meth 1-isopropyl-1-methylbutyl acrylate, 1-ethyl-1-isopropylbutyl methacrylate, 1-isopropyl-1-propylbutyl methacrylate, 1-isopropyl-1,2- methacrylate Dimethylpropyl, 1,1-diisopropylpropyl methacrylic acid, 1,1-diisopropylbutyl methacrylic acid, 1,1-diisopropyl-2-methylpropyl methacrylate;

Methacrylic acid 4-methylcyclohexyl, methacrylic acid 2-methylcyclohexyl, methacrylic acid 4-isopropylcyclohexyl, methacrylic acid 2-isopropylcyclohexyl, methacrylic acid 4-t-butylcyclohexyl, methacrylic acid 2-t-butylcyclohexyl acrylate;

2-Norbornyl methacrylate, 2-methyl-2-norbornyl methacrylate, 2-ethyl-2-norbornyl methacrylate, 2-isobornyl methacrylate, 2-methyl methacrylate -2-isobornyl, 2-ethyl methacrylate-2-isobornyl, methacrylic acid 8-tricyclo[5.2.1.0 ^2,6 ]decanyl, methacrylate 8-methyl-8-tricyclo[ 5.2.1.0 ^2,6 ]decanyl, methacrylate 8-ethyl-8-tricyclo[5.2.1.0 ^2,6 ]decanyl, methacrylate 2-adamantyl, methacrylate 2-methyl-2- Adamantyl, 2-ethyl methacrylate-2-adamantyl, 1-adamantyl methacrylate, 2-fenyl methacrylate, 2-methyl-2-phenyl methacrylate, 2-ethyl methacrylate -2-phenkyl, decalin-1-yl methacrylate, decalin-2-yl methacrylate, and the like.

(Copolymerizable monomer)

Examples of the copolymerizable monomer include (meth)acrylamides such as N,N-dimethyl (meth)acrylamide and N-methylol (meth)acrylamide; Unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, cinnamic acid, and vinylbenzoic acid; Unsaturated polyhydric carboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid and mesaconic acid; Unsaturated monocarboxylic acids in which chains are extended between an unsaturated group and a carboxy group, such as succinate mono (2-acryloyloxyethyl) and succinate mono (2-methacryloyloxyethyl); Unsaturated acid anhydrides such as maleic anhydride and itaconic anhydride; Styrene, α-methylstyrene, α-chlorostyrene, pt-butylstyrene, p-methylstyrene, p-chlorostyrene, o-chlorostyrene, 2,5-dichlorostyrene, 3,4-dichlorostyrene, vinyltoluene, methyl Aromatic vinyls such as oxystyrene; N-substituted maleimides such as methyl maleimide, ethyl maleimide, isopropyl maleimide, cyclohexyl maleimide, phenyl maleimide, benzyl maleimide, and naphthyl maleimide; Conjugated dienes such as 1,3-butadiene, isoprene, and chloroprene; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl benzoate; Methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether , Vinyl ethers such as methoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, 2-hydroxyethyl vinyl ether, and 4-hydroxybutyl vinyl ether; N-vinyl compounds, such as N-vinylpyrrolidone, N-vinyl caprolactam, N-vinylimidazole, N-vinylmorpholine, and N-vinylacetamide; Unsaturated isocyanates such as isocyanatoethyl (meth)acrylate and allyl isocyanate; Vinyl cyanides such as acrylonitrile and methacrylonitrile; And the like.

(Method of manufacturing acrylic resin)

As a method for producing the acrylic resin according to the present invention, a polymerization method generally performed such as cast polymerization, bulk polymerization, suspension polymerization, solution polymerization, emulsion polymerization, and anionic polymerization can be used. Among them, since it is possible to reduce the incorporation of microscopic foreign matters unsuitable for optical use, bulk polymerization or solution polymerization without using a suspending agent or emulsifier is preferable.

<<Solution polymerization>>

In the case of performing solution polymerization, a solution prepared by dissolving a mixture of monomers in a solvent of an aromatic hydrocarbon such as toluene and ethylbenzene can be used. In the case of polymerization by bulk polymerization, polymerization can be initiated by irradiation of free radicals generated by heating or ionizing radiation so as to be performed normally.

As the initiator used in the polymerization reaction, any initiator used in radical polymerization can be used, for example, azo compounds such as azobisisobutylnitrile; Organic peroxides, such as benzoyl peroxide, lauroyl peroxide, and t-butyl peroxy-2-ethylhexanoate, can be used.

In particular, when polymerization is carried out at a high temperature of 90° C. or higher, solution polymerization is common, and therefore, a 10-hour half-life temperature of 80° C. or higher, and a peroxide, an azobis initiator, etc. soluble in the organic solvent used are preferable. Specifically, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-azobis(1-cyclohexanecarbonitrile), 2-(carbamoyl azo)isobutyronitrile, etc. are mentioned. It is preferable to use these initiators in the range of 0.005-5 mass% with respect to 100 mass% of all monomers, for example.

In the polymerization reaction, as the molecular weight modifier used as necessary, any one generally used in radical polymerization can be used, for example, butyl mercaptan, octyl mercaptan, dodecyl mercaptan, and 2-ethyl thioglycolate Mercaptan compounds, such as hexyl, are mentioned as a particularly preferable thing. These molecular weight modifiers are added in a concentration range in which the molecular weight of the acrylic resin is controlled within the above preferred range.

<<Bulk polymerization>>

The bulk polymerization is carried out by continuously extracting a partial polymer obtained by staying in the reaction vessel for a predetermined time while continuously supplying a monomer component and a polymerization initiator into the reaction vessel, for example, and a copolymer can be produced with high productivity. .

The polymerization initiator used when polymerizing the monomer component is not particularly limited, and for example, azo compounds such as azobisisobutyronitrile, 1,1-di(tert-butylperoxy)cyclohexane, benzoyl peroxide , p-chlorobenzoyl peroxide, diisopropylperoxycarbonate, di-2-ethylhexylperoxycarbonate, t-butylperoxypivalate, t-butylperoxy (2-ethylhexanoate) Known radical polymerization initiators, such as peroxides, can be used. Polymerization initiators may be used alone or in combination of two or more. In addition, the amount used is usually 0.01 to 5% by mass based on the total amount of the mixture. The heating temperature in thermal polymerization is usually 40 to 200°C, and the heating time is usually about 30 minutes to 8 hours.

When polymerizing the monomer component, a chain transfer agent can be used if necessary. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, and 2-ethylhexylthioglycolate as suitable ones. One type of chain transfer agent may be used, or two or more types may be used in combination.

<<Suspension polymerization>>

In the case of suspension polymerization, those used for ordinary suspension polymerization can be used, and organic peroxides and azo compounds are exemplified.

In addition, as the suspension stabilizer, a commonly used known material may be used, and examples thereof include organic colloidal polymer substances, inorganic colloidal polymer substances, inorganic fine particles, and combinations of these and surfactants.

As the aqueous medium for polymerizing the monomer mixture, a mixed medium of water or a water-soluble solvent such as water and alcohol (eg, methanol and ethanol) may be mentioned. The amount of the aqueous medium to be used is usually 100 to 1000 parts by mass based on 100 parts by mass of the monomer mixture in order to stabilize the crosslinked resin particles.

Further, in order to suppress the generation of emulsified particles in an aqueous system, water-soluble polymerization inhibitors such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, and polyphenols may be used.

In addition, other suspension stabilizers may be added as necessary. For example, phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate, pyrophosphate such as zinc pyrophosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, Poorly water-soluble inorganic compounds such as aluminum hydroxide, calcium metasilicate, calcium sulfate, and barium sulfate, and dispersion stabilizers for polyvinyl alcohol.

It is also possible to use the above suspension stabilizer and surfactants such as anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants in combination.

Examples of anionic surfactants include fatty acid oils such as sodium oleate and castor oil, kali, alkyl sulfates such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkyl sulfonates. , Alkyl naphthalene sulfonate, alkanesulfonic acid salt, succinic sulfonate, dialkyl sulfosuccinate, alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene alkyl sulfate, etc. Can be lifted.

As a nonionic surfactant, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, And oxyethylene-oxypropylene block polymers.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

Examples of the amphoteric surfactant include lauryl dimethylamine oxide and phosphoric acid ester or phosphorous acid ester surfactants.

These suspension stabilizers and surfactants may be used alone or in combination of two or more, but are used by appropriately adjusting the selection or amount of a suspension stabilizer in consideration of the diameter of the obtained particles and dispersion stability during polymerization. Usually, the addition amount of the suspension stabilizer is 0.5 to 15 parts by mass with respect to 100 parts by mass of the monomer mixture, and the addition amount of the surfactant is 0.001 to 10 parts by mass with respect to 100 parts by mass of the aqueous medium.

The monomer mixture is added to the aqueous medium thus prepared, and polymerization is carried out.

As a method of dispersing a monomer mixture, for example, a monomer mixture is directly added to an aqueous medium and dispersed in an aqueous medium as monomer droplets by a stirring force such as a propeller blade, and a dispersing machine that uses a high shear force composed of a rotor and a stator. A method of dispersing using a homomixer or an ultrasonic disperser, etc. are mentioned.

Then, the aqueous suspension in which the monomer mixture is dispersed as spherical droplets is heated to initiate polymerization. During the polymerization reaction, the aqueous suspension is preferably stirred, and the stirring may be performed slowly enough to prevent floating of spherical droplets and sedimentation of particles after polymerization, for example.

The polymerization temperature is preferably about 30 to 100°C, more preferably about 40 to 80°C. And as the time to maintain this polymerization temperature, about 0.1 to 20 hours is preferable.

After polymerization, the particles are separated as a water-containing cake by suction filtration, centrifugal dehydration, centrifugation, pressure dehydration, or the like, and the obtained water-containing cake is washed with water and dried to obtain target particles. Here, adjustment of the average particle diameter of the particles can be performed by adjusting the mixing conditions of the monomer mixture and water, the amount of addition of the suspension stabilizer or surfactant, and the stirring conditions and dispersion conditions of the stirrer.

<Other ingredients>

The optical film of the present invention may further contain other components as long as the effect of the present invention is not impaired. Examples of other components include residual solvents, ultraviolet absorbers, antioxidants, and the like.

[Manufacturing method of optical film]

The method for producing an optical film of the present invention is a method for producing an optical film containing organic fine particles, a polymer containing at least an alicyclic hydrocarbon monomer having a polar group, or a polymer containing at least a (meth)acrylic monomer, and the organic fine particles As an example, it is characterized in that organic fine particles subjected to treatment to remove surfactants present around them are used.

Specifically, the method for producing the optical film of the present invention is preferably produced by a solution casting method. That is, (1) a step of removing a surfactant from the organic fine particles, and (2) a polymer containing the organic fine particles subjected to a treatment of removing the surfactant, and an alicyclic hydrocarbon monomer having at least a polar group. Or a step of obtaining a dope containing at least a polymer containing a (meth)acrylic monomer and a solvent, and (3) casting the obtained dope on a flexible substrate such as a metal support, drying and peeling to obtain a film-like substance; and , (4) It is preferable to provide a step of stretching the obtained film-like material while drying it.

About the process of (1)

<Organic fine particles subjected to treatment to remove surfactant>

Since organic fine particles are produced by emulsion polymerization, the use of a surfactant is essential for the production, and a surfactant is present around the organic fine particles produced by emulsion polymerization. Specifically, the surface active agent adheres to the surface of the organic fine particles. As a treatment for removing this surfactant, a method of washing and heating may be mentioned.

(washing)

As a washing method for removing the surfactant, the powder of organic fine particles obtained by emulsion polymerization described below is dispersed in a washing solvent, or the emulsion obtained by emulsion polymerization is diluted with a washing solvent, filtered, concentrated, and then further diluted. , Filtration and concentration are repeated to remove the surfactant.

In the above washing method, since the organic fine particles are produced by emulsion polymerization, it is possible to reduce labor and cost by not pulverizing the emulsion by repeating dilution, filtration, and concentration from the state of the emulsion after polymerization. It is preferable in that it can be.

(Cleaning solvent)

Examples of the cleaning solvent include water or alcohol, but cleaning with alcohol is more preferable than water in terms of having a higher cleaning effect. This is because the surfactant adheres to the surface of the organic fine particles by a hydrophobic group, and water only acts on the hydrophilic group on the opposite side of the surfactant, so the ability to remove the surfactant adhered to the surface of the organic fine particles is small. On the other hand, since alcohol can also act on a portion of a hydrophobic group attached to the organic fine particles, it has a large ability to remove a surfactant.

When the solvent of the slurry or wet cake containing the organic fine particles after washing is water, it is powdered by spray drying or freeze drying to obtain organic fine particles from which water is removed, and a dispersion is prepared using this, and the dispersion is optically It is preferable to add it to the dope when producing a film. This is because dichloromethane is the main solvent of the dope used when manufacturing the optical film, and thus, when water is introduced into the dope, phase separation and incompatibility become unfavorable.

Further, it is preferable to change the solvent used for dilution from water to alcohol after the concentration. Thereby, the solvent of the slurry or wet cake can be replaced with alcohol from water. Since alcohol is compatible with dichloromethane, by dispersing this slurry or wet cake in a mixed solvent of dichloromethane and alcohol, fine particles that can be added to the dope when producing an optical film are not powdered by spray drying or freeze drying. It can be made into a dispersion of.

Further, the solvent of the slurry may be further changed from alcohol to dichloromethane. By changing to dichloromethane, it is preferable from the point that it becomes easy to introduce|introduce into the dope mainly dichloromethane. When the slurry is a dichloromethane solvent, since the alcohol content of the dope can be reduced, drying is quick and the surface quality of the film is improved.

The amount of water, alcohol, and dichloromethane added as the washing solvent is in the range of 5 to 100 parts by mass per 1 part by mass of the fine particles.

(percolation)

As the method of filtration, it can be carried out by a conventional method (dead-end filtration) using a membrane filter. Further, in order to improve the filtration speed, suction filtration may be performed or filtration may be performed using centrifugal force.

In addition, in the present invention, it is preferable to adopt cross-flow filtration rather than the dead-end filtration in that a cake is hardly formed and the filtration speed is improved.

In addition, the dilution, filtration, and concentration are repeated to remove the solvent containing the surfactant while circulating, add the solvent as much as it is concentrated, to decrease the concentration of the surfactant, and finally, by concentrating, the concentration of the surfactant is reduced. A slurry containing lowered organic fine particles can be obtained.

Further, the organic fine particles and the solvent may be separated by centrifugal sedimentation, and decantation of the solvent may be repeated to wash the organic fine particles.

When the particle size of the organic fine particles is small and the filtration efficiency is poor, it is preferable to add a salt to aggregate the organic fine particles by salting out to some extent, and then filter the filtration efficiency. Further, the organic fine particles and a solvent having poor dispersibility in which the SP value is separated from each other may be added to aggregate and filter the organic fine particles.

As the salt or the solvent with the SP values apart, known ones such as aqueous electrolytes and organic solvents can be used, but in terms of the productivity of filtration, magnesium salts such as magnesium chloride or magnesium sulfate, or calcium such as calcium acetate or calcium chloride It is preferred to use salts. As the addition amount of the salt or the solvent separated from the SP value, 1 to 10 parts by weight is preferable based on 1 part by weight of the organic fine particles.

(Device)

Examples of devices that can be used in the step (1) above include NGK Filltech Co., Ltd. Membrane Process System Standard (M-1) tester, Mitsubishi Kakoki Co., Ltd. Mitsubishi Dyna filter (rotary ceramic filter), etc. have.

(heating)

As a heating method for removing the surfactant, a method of heating in a state in which organic fine particles are emulsions is exemplified, whereby the surfactant can be hydrolyzed.

In addition, the surfactant can also be decomposed by heating, moist heat, and aging in a state where the organic fine particles are powder particles. Since the surfactant adheres to the surface of the organic fine particles in a substantially molecular state, the presence of a little moisture makes the surfactant more easily hydrolyzed, and this decomposition reaction is accelerated by heating.

The heating temperature varies depending on the heating time, but is preferably 1 to 100 hours at 40 to 160°C. Alternatively, it may be aged for 3 months at 60°C or for 6 months or longer at 23°C.

Further, in the above heating method, heating in a state in which a trace amount of water is added to the dispersion of organic fine particles for dope addition is preferable in that the surfactant can be hydrolyzed. In addition, since the said dispersion of organic fine particles for dope addition is added to dope, the content of water in the dispersion is preferably less than 1% by mass.

Further, by heating in the state of a dope containing organic fine particles and a trace amount of water, the surfactant can also be hydrolyzed.

In the step of preparing the dispersion of organic fine particles for dope addition and adding it to the dope, when the organic fine particles are dispersed in dichloromethane, if water is added after or before dispersion, water is separated into an upper layer, and the surfactant is extracted therein. Therefore, it can be removed by decantation.

About the process of (2)

In the step (2), the organic fine particles subjected to the treatment for removing the surfactant, a polymer containing at least an alicyclic hydrocarbon monomer having a polar group or a polymer containing at least a (meth)acrylic monomer, and a solvent are included. Get dope

The solvent used for dope contains an organic solvent (a good solvent) capable of dissolving at least a polymer containing the alicyclic hydrocarbon monomer having a polar group or a polymer containing a (meth)acrylic monomer.

Examples of the good solvent include chlorine-based organic solvents such as methylene chloride; Non-chlorine organic solvents, such as methyl acetate, ethyl acetate, acetone, and tetrahydrofuran, are contained. Among them, methylene chloride is preferred.

The solvent used for dope may further contain a poor solvent. Examples of poor solvents include linear or branched aliphatic alcohols having 1 to 4 carbon atoms. When the proportion of alcohol in the dope is increased, the film-like substance is likely to be gelled, and peeling from a flexible substrate such as a metal support is likely to be facilitated. Examples of linear or branched aliphatic alcohols having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Among these, ethanol is preferred from the viewpoints of dope stability and a relatively low boiling point and good drying properties.

The preparation of dope is an organic fine particle that has been subjected to a treatment for removing the above-described solvent, a polymer containing an alicyclic hydrocarbon monomer having a polar group or a polymer containing a (meth)acrylic monomer, and the above-described surfactant. (Also referred to as "organic fine particles") may be directly added and mixed and prepared; A resin solution obtained by dissolving a polymer containing an alicyclic hydrocarbon monomer having a polar group or a polymer containing a (meth)acrylic monomer in the above-described solvent, and a fine particle dispersion obtained by dispersing the organic fine particles after the removal treatment in the above-described solvent. They may be prepared in advance, and they may be mixed and prepared.

The method of adding the organic fine particles after the removal treatment to the solvent is not particularly limited, and the organic fine particles may be individually added to the solvent or may be added to the solvent as an aggregate of the organic fine particles. The aggregate of organic fine particles contains a plurality of organic fine particles whose interconnection (fusion) is suppressed. Therefore, when the aggregate of organic fine particles is dispersed in a polymer or solvent containing a polymer or a solvent containing an alicyclic hydrocarbon monomer having a polar group or a polar group, it is easily separated into organic fine particles. , The dispersibility of organic fine particles can be improved. The aggregate of organic fine particles can be obtained by spray-drying a slurry containing organic fine particles and inorganic powder, for example.

About the process of (3)

In the step (3), the obtained dope is flexible on a flexible substrate such as a metal support. Casting of dope can be performed by discharging from the casting die.

Next, the solvent in the dope cast on a flexible substrate such as a metal support is evaporated and dried. The dried dope is peeled from a flexible substrate such as a metal support to obtain a film-like material. The residual solvent amount of the dope when peeling from a flexible substrate such as a metal support (amount of residual solvent during peeling) is preferably 10 to 150% by mass from the viewpoint of making it easy to reduce the retardation Ro and Rt of the obtained optical film. And it is more preferable that it is 20-40 mass %. When the residual solvent amount at the time of peeling is 10% by mass or more, when drying or stretching, a polymer containing an alicyclic hydrocarbon monomer having a polar group or a polymer containing a (meth)acrylic monomer is likely to flow and become unoriented. , Ro and Rt of the obtained optical film are easily reduced. If the amount of residual solvent at the time of peeling is 150% by mass or less, the force required for peeling the dope is difficult to be excessively large, so that it is easy to suppress the dope from breaking.

The amount of residual solvent in dope is defined by the following formula. It is the same also in the following.

Amount of residual solvent of dope (mass%) = (mass before heat treatment of dope-mass after heat treatment of dope)/mass after heat treatment of dope x 100

In addition, the heat treatment at the time of measuring the amount of residual solvent means a heat treatment at 120°C for 60 minutes.

About the process of (4)

In the step (4), the obtained film-like material is stretched while drying. Stretching may be performed to suit the required optical properties, and it is preferable to stretch in at least one direction, stretching in two directions orthogonal to each other (e.g., the transverse direction (TD direction) of a film-like material, and conveyance orthogonal to it) Biaxial stretching in the direction (MD direction) may be employed.

In the case of biaxial stretching of the film-like material, not only is it easy to adjust the phase difference to a predetermined range, but also the stretching tension applied to the periphery of the organic fine particles can be made isotropic, so that the isotropic voids around the organic fine particles are uniformly formed. Easy to form Thereby, since isotropic voids can be formed around the organic fine particles, the adhesive easily penetrates into the voids, and the adhesiveness with the polarizer is easily improved.

The draw ratio can be made 1.01 to 3.5 times, for example, from the viewpoint of making the optical film function as a retardation film for VA, and can be made 1.01 to 1.3 times, for example, from the viewpoint of making it function as a retardation film for IPS. The higher the draw ratio, the more likely the residual stress of the obtained optical film is. The draw ratio is defined as (size in the stretching direction of the film after stretching)/(size in the stretching direction of the film before stretching). In addition, when performing biaxial stretching, it is preferable to set it as the said stretching ratio in each of the TD direction and the MD direction.

In addition, the in-plane slow axis direction (the direction in which the refractive index becomes maximum in the surface) of the optical film is usually the direction in which the draw ratio becomes maximum.

The stretching temperature is (Tg-65)°C to (Tg+60)°C when the glass transition temperature of the polymer containing the polar group-containing alicyclic hydrocarbon monomer or the polymer containing the (meth)acrylic monomer is Tg. It is preferable, it is more preferable that it is (Tg-50) degreeC-(Tg+50) degreeC, and it is still more preferable that it is (Tg-30) degreeC-(Tg+50) degreeC. When the stretching temperature is (Tg-30)°C or higher, not only is it easy to make the film-like material flexible enough for stretching, but also the tension applied to the film-like material during stretching is not too large, so that excessive residual stress is difficult to remain in the resulting optical film. , Ro and Rt are also difficult to increase excessively. When the stretching temperature is (Tg+60)°C or less, moderate residual stress is likely to remain in the optical film after stretching, and generation of bubbles due to vaporization of the solvent in the film-like material is also highly suppressed. The stretching temperature can be specifically set to 100 to 220°C.

It is preferable that the amount of residual solvent in the film-like material at the start of stretching is 2 to 50% by mass. When the amount of the residual solvent at the beginning of stretching is 2% by mass or more, the substantial Tg of the film-like material during stretching is lowered due to the plasticizing effect due to the residual solvent, so that Ro and Rt of the optical film are difficult to increase. When the amount of the residual solvent at the start of stretching is 50% by mass or less, generation of bubbles due to vaporization of the solvent in the film-like material can be highly suppressed.

The stretching of the film-like material in the MD direction can be performed by, for example, a method (roll method) by giving a circumferential speed difference to a plurality of rolls and using the roll circumferential speed difference therebetween. The stretching in the TD direction of the membrane-like material can be performed by, for example, fixing both ends of the membrane-like material with clips or pins, and widening the gap between the clips and pins in the traveling direction (tenter method).

[Physical properties of optical film]

(Phase difference Ro and Rt)

When the optical film of the present invention is used as, for example, a retardation film for VA mode, the retardation Ro in the in-plane direction measured in an environment of a measurement wavelength of 550 nm and 23° C. 55% RH is preferably within a range of 20 to 120 nm. And more preferably in the range of 30 to 100 nm. The retardation Rt in the thickness direction of the optical film is preferably in the range of 70 to 350 nm, and more preferably in the range of 100 to 320 nm.

Ro and Rt of the optical film are each defined by the following formula.

Equation (2a): Ro=(nx-ny)×d

Equation (2b): Rt=((nx+ny)/2-nz)×d

(In the formula,

nx represents the refractive index in the in-plane slow axis direction (the direction in which the refractive index becomes maximum) of the optical film,

ny represents the refractive index in a direction orthogonal to the in-plane slow axis of the optical film,

nz represents the refractive index in the thickness direction of the optical film,

d represents the thickness (nm) of the optical film.)

The in-plane slow axis of an optical film refers to an axis at which the refractive index becomes the largest in the film surface. The in-plane slow axis of the optical film can be confirmed by an automatic birefringence meter Axo Scan (manufactured by Axo Scan Mueller Matrix Polarimeter).

Measurement of Ro and Rt of an optical film can be performed by the following method.

1) The optical film is humidified in an environment of 23°C and 55% RH for 24 hours. The average refractive index of this optical film is measured with an Abbe refractometer, and the thickness d is measured using a commercially available micrometer.

2) Retardation Ro and Rt of the optical film after humidity control at a measurement wavelength of 550 nm, respectively, using an automatic birefringence meter Axo Scan (manufactured by Axo Scan Mueller Matrix) in an environment of 23°C and 55% RH It is measured under

The retardation Ro and Rt of the optical film can be adjusted mainly by the draw ratio. In order to increase the retardation Ro and Rt of the optical film, it is preferable to increase the draw ratio.

(thickness)

The thickness of the optical film of the present invention is preferably in the range of 5 to 100 µm, and more preferably in the range of 5 to 40 µm.

[Polarizer]

The polarizing plate according to the present invention contains a polarizer and the optical film of the present invention. It is preferable that the optical film of this invention is arrange|positioned on at least one surface (at least a surface facing a liquid crystal cell) among polarizers. The polarizer and the optical film are adhered through an adhesive layer.

<polarizer>

The polarizer is an element that allows only light of a polarization surface in a predetermined direction to pass, and is a polyvinyl alcohol-based polarizing film. Polyvinyl alcohol-based polarizing films include those obtained by dyeing a polyvinyl alcohol-based film with iodine and dyeing a dichroic dye.

The polyvinyl alcohol-based polarizing film may be a film (preferably, a film subjected to a durability treatment with a boron compound) after uniaxially stretching a polyvinyl alcohol-based film and then dyed with iodine or a dichroic dye; After dyeing the polyvinyl alcohol-based film with iodine or a dichroic dye, the film may be uniaxially stretched (preferably, a film further subjected to durability treatment with a boron compound). The absorption axis of the polarizer is usually parallel to the maximum stretching direction.

For example, ethylene modification with a content of 1 to 4 mol% of an ethylene unit, a polymerization degree of 2000 to 4000, and a saponification degree of 99.0 to 99.99 mol% described in JP 2003-248123 A, JP 2003-342322 A, etc. Polyvinyl alcohol is used.

It is preferable that the thickness of the polarizer is 5 to 30 µm, and in order to thin the polarizing plate, it is more preferable that it is in the range of 5 to 20 µm.

<Other optical films>

When the optical film of the present invention is disposed only on one side of the polarizer, another optical film may be disposed on the other side of the polarizer. Examples of other optical films include commercially available cellulose ester films (e.g., Konica Minolta Tak KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UE, KC6UY, KC4UY KC8UY-HA, KC2UA, KC4UA, KC6UAKC, 2UAH, KC4UAH, KC6UAH, Sang Konica Minolta Co., Ltd., Fuji Tag T40UZ, Fuji Tag T60UZ, Fuji Tag T80UZ, Fuji Tag TD80UL, Fuji Tag TD40UL, Fuji Tag TD40UL R02, Fuji Tag R06, and the above Fujifilm Co., Ltd. product) etc. are included.

The thickness of the other protective film is not particularly limited, but it is preferably 10 to 100 µm, more preferably 10 to 60 µm, and particularly preferably 20 to 60 µm.

<Method of manufacturing a polarizing plate>

The polarizing plate according to the present invention can be obtained by bonding a polarizer and the optical film of the present invention through an adhesive. The adhesive may be a completely saponified polyvinyl alcohol aqueous solution (water paste) or an active energy ray-curable adhesive.

Especially, it is preferable that the optical film of this invention and a polarizer are bonded by an active energy ray-curable adhesive from the point that strength is high even if a thin film is easy to obtain a polarizing plate excellent in planarity.

The active energy ray-curable adhesive may be any of a photoradical polymerization type composition using photoradical polymerization, a photocationic polymerization type composition using photocationic polymerization, and a hybrid type composition using photoradical polymerization and photocationic polymerization in combination.

Examples of the photo-radical polymerizable composition include a radical polymerizable compound containing a polar group such as a hydroxy group or a carboxyl group described in Japanese Patent Laid-Open No. 2008-009329 and a composition containing a radical polymerizable compound not containing a polar group in a specific ratio. Is known. In particular, the radical polymerizable compound is preferably a compound having an ethylenically unsaturated bond capable of radical polymerization. Preferred examples of the compound having an ethylenically unsaturated bond capable of radical polymerization include a compound having a (meth)acryloyl group. Examples of the compound having a (meth)acryloyl group include an N-substituted (meth)acrylamide compound, a (meth)acrylate compound, and the like. (Meth)acrylamide means acrylamide or methacrylamide.

As a photocationic polymerization type composition, as disclosed in Japanese Patent Application Laid-Open No. 2011-028234, (α) cationic polymerizable compound, (β) photocationic polymerization initiator, (γ) maximized for light with a wavelength longer than 380 nm. The composition containing each component of a photosensitizer which shows absorption, and (δ) naphthalene-type photosensitizer auxiliary agent is mentioned.

The manufacturing method of a polarizing plate using an active energy ray-curable adhesive includes (i) a step of applying an active energy ray-curable adhesive to at least one of the adhesive surfaces of the polarizer and the optical film, and (ii) the polarizer and optical through the obtained adhesive layer. The process of bonding the film, (iii) a process of irradiating an active energy ray in a state in which the polarizer and the optical film are bonded through the adhesive layer to cure the adhesive layer to obtain a polarizing plate, and (iv) the obtained polarizing plate It includes a process of punching (cutting) into a shape. Before the step (i), if necessary, a step of performing adhesion facilitation treatment (corona treatment, plasma treatment, etc.) may be performed on the surface to which the polarizer of the optical film is adhered (iv).

In the step (i), it is preferable to apply the active energy ray-curable adhesive so that the thickness of the adhesive layer after curing is, for example, 0.01 to 10 µm, preferably 0.5 to 5 µm.

In the step (iii), as the active energy ray to be irradiated, visible light, ultraviolet ray, X-ray, electron beam, or the like can be used. Since handling is easy and curing speed is sufficient, it is generally preferable to use ultraviolet rays. The irradiation conditions of ultraviolet rays may be conditions capable of curing the adhesive. For example, the irradiation amount of ultraviolet rays is preferably 50 to 1500 mJ/cm 2, and more preferably in the range of 100 to 500 mJ/cm 2 as the accumulated light amount.

[Liquid crystal display device]

It is preferable that the liquid crystal display device according to the present invention includes a liquid crystal cell, a first polarizing plate disposed on one side of the liquid crystal cell, and a second polarizing plate disposed on the other side of the liquid crystal cell. It is preferable that one or both of the first and second polarizing plates are the above-described polarizing plates.

1 is a schematic diagram showing an example of a basic configuration of a liquid crystal display device. As shown in FIG. 1, the liquid crystal display device 10 according to the present invention includes a liquid crystal cell 30, a first polarizing plate 50 disposed on one side of the liquid crystal cell 30, and a liquid crystal cell 30. It is preferable to include a second polarizing plate 70 disposed on the other side of) and a backlight 90 disposed on a side opposite to the liquid crystal cell 30 with the second polarizing plate 70 interposed therebetween.

The display modes of the liquid crystal cell 30 are, for example, Super-Twisted Nematic (STN), Twisted Nematic (TN), Optically Compensated Bend (OCB), Hybridaligned Nematic (HAN), Vertical Alignment (VA), Multi- domain Vertical Alignment), Patterned Vertical Alignment (PVA), In-Plane-Switching (IPS), and the like. Among them, VA (MVA, PVA) mode and IPS mode are preferred.

The first polarizing plate 50 includes a first polarizer 51 disposed on one surface of the liquid crystal cell 30 (a surface on the viewing side), and a surface of the first polarizer 51 on the opposite side of the liquid crystal cell 30 It includes a protective film 53 (F1) arranged on the (view side surface), and a protective film 55 (F2) arranged on the surface of the first polarizer 51 on the liquid crystal cell 30 side.

The second polarizing plate 70 includes a second polarizer 71 disposed on the other surface of the liquid crystal cell 30 (the surface on the backlight 90 side), and the liquid crystal cell 30 side of the second polarizer 71 The protective film 73 (F3) disposed on the side of the second polarizer 71 and the protective film 75 (F4) disposed on the side opposite to the liquid crystal cell 30 (the side of the backlight 90 side) )).

It is preferable that the absorption axis of the first polarizer 51 and the absorption axis of the second polarizer 71 are orthogonal (made of cross-Nicol).

At least one of the protective films 53 (F1), 55 (F2), 73 (F3) and 75 (F4)) may be used as the optical film of the present invention. Especially, the optical film of this invention is used suitably as a protective film 55 (F2) or 73 (F3). A liquid crystal display device including the optical film of the present invention as the protective film 55 (F2) or 73 (F3) has a good front contrast, and the display unevenness is also reduced.

By using the polarizing plate according to the present invention, it is possible to obtain a liquid crystal display device having excellent visibility such as display unevenness and front contrast even in a large-screen liquid crystal display device having a screen of 30 or more.

<Example>

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, in the following examples, operation was performed at room temperature (25°C) unless otherwise specified. In addition, unless otherwise specified, "%" and "part" mean "mass%" and "mass part", respectively.

[Production of Optical Film 1] (Example 1)

<Production of seed particles>

To a polymerization reactor equipped with a stirrer and a thermometer, 1000 g of deionized water was put, 50 g of methyl methacrylate and 6 g of t-dodecylmercaptan were added thereto, and the mixture was heated to 70° C. with nitrogen substitution under stirring. The internal temperature was maintained at 70° C., and 20 g of deionized water in which 1 g of potassium persulfate was dissolved as a polymerization initiator was added, followed by polymerization for 10 hours. The average particle diameter of the seed particles in the obtained emulsion was 0.05 µm.

<Preparation of organic fine particles 1>

In a polymerization reactor equipped with a stirrer and thermometer, 650 g of deionized water dissolving 2.4 g of sodium lauryl sulfate as a surfactant was added thereto, and 66 g of methyl methacrylate (indicated as MMA in the table below) as a monomer mixture, 20 g of styrene and ethylene. A mixed solution of 64 g of glycol dimethacrylate and 1 g of azobisisobutyronitrile as a polymerization initiator was added. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of an emulsion containing the seed particles was added and stirred at 30°C for 1 hour to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 5 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), and the polymer fine particles (organic fine particles) and sodium laurate adhering to the surface were removed. An emulsion of the containing composite was obtained. The solid content concentration of the obtained organic fine particles was 20%.

<Preparation of an aggregate of organic fine particles 1>

The emulsion was spray-dried under the following conditions with a spray dryer (model: atomizer take-up system, model number: TRS-3WK) manufactured by Sakamoto Kiken as a spray dryer to obtain an aggregate of organic fine particles.

Feed rate: 25mL/min

Atomizer rotation speed: 11000rpm

Air volume: 2㎥/min

Spray dryer slurry inlet temperature: 100℃

Polymer particle assembly outlet temperature: 50℃

<Treatment 1 for removal of surfactant of organic fine particles 1>

95 parts by mass of deionized water was added to the organic fine particle dispersion tank, and then 5 parts by mass of the organic fine particles 1 were added, followed by stirring and mixing with stirring for 30 minutes with a dissolver, followed by dispersion with 10,000 tonnes of Gaulin.

This dispersion was filtered through an omnipore membrane filter (maximum pore diameter of 0.2 µm) to obtain a wet cake containing 5 parts by mass of organic fine particles and 5 parts by mass of deionized water. The filtration time was 60 minutes.

This wet cake was again put into a dispersion tank, 90 parts by mass of deionized water was added, and a dispersion liquid was stirred and mixed while stirring with a dissolver for 30 minutes.

This dispersion was filtered again with an omnipore membrane filter (maximum pore diameter: 0.2 µm) to obtain a wet cake containing 5 parts by mass of organic fine particles and 5 parts by mass of deionized water.

Organic fine particles from which the surfactant was removed were obtained by vacuum drying this wet cake at 50°C.

For the organic fine particles after the removal treatment, the refractive index and average particle diameter were measured by the following method. In addition, the solubility of the active agent used in the production of organic fine particles was also measured by the following method.

<Measurement of refractive index>

The obtained organic fine particles were press-molded, the average refractive index of the molded article was measured with a laser refractometer, and the value was taken as the refractive index of the organic fine particles.

In addition, in this embodiment, the refractive index means the refractive index with respect to light of a wavelength of 550 nm at 23 degreeC.

<Measurement of average particle diameter>

About the obtained organic fine particles, the average particle diameter was calculated|required by the dynamic light scattering method using MICROTRAC UPA150 (manufactured by Nikkiso Corporation).

<Measurement of solubility>

The solubility of the surfactant used in the preparation of the organic fine particles in ethanol, dichloromethane and water was dissolved in various solvents at 23° C. and visually judged.

Specifically, for example, with respect to 100 g of water at 23°C, 10.0 g is dissolved by gradually adding a surfactant, and when insoluble matter is observed at 10.1 g, the solubility in water is 10/(100+10)= It becomes 9.1 mass %. In addition, the measurement results of solubility are shown in the table below.

<Synthesis of polymer containing alicyclic hydrocarbon monomer having a polar group>

As an alicyclic hydrocarbon monomer (norbornene-based monomer) having a polar group, 100 parts by mass of the following compound, 3.6 parts by mass of 1-hexene as a molecular weight modifier, and 200 parts by mass of toluene were put into a nitrogen-substituted reaction vessel and heated to 80°C. I did. In this, as a polymerization catalyst, triethylaluminum ((C ₂ H ₅ ) ₃ Al) 1.5 mol/L of 0.17 parts by mass of a toluene solution, and t-butanol and methanol-modified tungsten hexachloride (WCl ₆ ), t-butanol:methanol:tungsten = 0.35:0.3:1 (molar ratio) of WCl ₆ solution (concentration 0.05 mol/l) 1.0 parts by mass was added, heated and stirred at 80° C. for 3 hours to conduct ring-opening polymerization reaction to obtain a polymer solution . The polymerization conversion rate in this polymerization reaction was 98%.

4000 parts by mass of the obtained polymer solution was put into an autoclave, and 0.48 parts by mass of RuHCl(CO)[P(C ₆ H ₅ ) ₃ ] ₃ was added to the polymer solution, and the hydrogen gas pressure was 10 MPa and the reaction temperature was 160°C. It heated and stirred for 3 hours, and hydrogenated reaction was performed.

After cooling the obtained reaction solution, hydrogen gas was released under pressure, and the reaction solution was poured into a large amount of methanol to separate and recover the coagulated product. The collected coagulated product was dried to obtain a cycloolefin-based polymer (indicated by COP in the following table).

When the weight average molecular weight of the polymer containing the obtained alicyclic hydrocarbon monomer was measured, the weight average molecular weight was 140000. Further, the refractive index of the polymer containing the obtained alicyclic hydrocarbon monomer was measured in the same manner as the method of measuring the refractive index of the organic fine particles described above.

<Preparation of organic fine particle addition liquid>

After stirring and mixing the following materials for 50 minutes with a dissolver, dispersion was performed with 10,000 ton Gaulin. This was filtered with Finemet NM5P-2400 manufactured by Nippon Seisen Co., Ltd. to prepare an organic fine particle addition liquid having an organic fine particle content of 3.0% by mass.

Organic fine particles after the removal treatment 1: 3 parts by mass

Dichloromethane: 97 parts by mass

<Preparation of dope containing organic fine particles>

First, methylene chloride and ethanol were added to a pressure dissolution tank. Next, the polymer containing the alicyclic hydrocarbon monomer obtained above was put into the pressure dissolution tank while stirring, and further 3% by mass of the organic fine particle addition liquid was added to prepare a dope of the following composition. This was filtered at a filtration flow rate of 300 L/m 2·h and a filtration pressure of 1.0×10 ⁶ Pa using Azumi Rossi No. 244 (filtration accuracy 7 μm) manufactured by Azumi Rossi.

(The composition of dope)

Polymer containing the alicyclic hydrocarbon monomer: 98.5 parts by mass

Dichloromethane: 250.0 parts by mass

Ethanol: 20.0 parts by mass

3 mass% organic fine particle addition liquid: 50.0 mass parts (fine particle weight: 1.5 mass parts)

The solid material in the dope has a composition of a polymer (98.5% by mass) and organic fine particles (1.5% by mass) containing an alicyclic hydrocarbon monomer.

<Tabernacle>

The prepared dope was fed from a pressure dissolution tank to a pressurized die by a gear pump, and cast (cast) onto a casting substrate (endless support made of stainless steel). After evaporating the solvent until the amount of the residual solvent in the flexible dope became 40% by mass, the obtained film-like material was peeled from the flexible substrate (a stainless steel endless support) with a peeling tension of 130 N/m. The peeled film-like material was conveyed by a tenter stretching device while drying, and conveyed into the tenter at a draw ratio of 50% (1.5 times) in the width direction. At this time, drying conditions from peeling to tenter were adjusted so that the amount of residual solvent at the time of stretching might be 11 mass %. In addition, the temperature of the tenter stretching device was 160°C, and the stretching speed was 200%/min.

Next, drying was terminated while conveying the inside of the drying apparatus with a number of rollers. The drying temperature was 130°C, and the conveyance tension was 100 N/m. Thereafter, after sliting both ends of the obtained optical film, embossing was performed to prepare an optical film 1 having a dry film thickness of 40 µm.

[Production of Optical Film 2] (Example 2)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 2 was produced in the same manner except that the surfactant removal treatment was performed by the following method.

<Treatment 2 of removing surfactant of organic fine particles 1>

95 parts by mass of ethanol was added to the organic fine particle dispersion tank, and then 5 parts by mass of the organic fine particles 1 were added, followed by stirring and mixing while stirring with a dissolver for 30 minutes, followed by dispersion with 10,000 tonnes of Gaulin. This dispersion was filtered through an omnipore membrane filter (maximum pore diameter 0.2 µm) to obtain a wet cake containing 5 parts by mass of organic fine particles 1 and 5 parts by mass of ethanol. The filtration time was 70 minutes. This wet cake was again put into a dispersion tank, 90 parts by mass of ethanol was added, and a dispersion liquid was stirred and mixed while stirring with a dissolver for 30 minutes. This dispersion was filtered again with an omnipore membrane filter (maximum pore diameter 0.2 µm) to obtain a wet cake containing 5 parts by mass of organic fine particles 1 and 5 parts by mass of ethanol. Organic fine particles 1 from which the surfactant was removed were obtained by vacuum drying this wet cake at 50°C.

[Production of Optical Film 3] (Example 3)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 3 was produced in the same manner except that the surfactant removal treatment was performed by the following method.

<Treatment 3 for removing surfactant of organic fine particles 1>

20 parts by mass of deionized water was added to the organic fine particle dispersion tank, and then 5 parts by mass of the organic fine particles 1 were added, followed by stirring and mixing with stirring for 30 minutes with a dissolver, followed by dispersion with 10,000 tonnes of Gaulin. 75 parts by mass of a 10% solution of NaCl was added to this dispersion, followed by stirring and mixing to obtain a dispersion in which organic fine particles were aggregated.

This dispersion was filtered with an omnipore membrane filter (maximum pore diameter of 0.2 µm) to obtain a wet cake containing 5 parts by mass of organic fine particles 1 and 5 parts by mass of deionized water. The filtration time was 10 minutes. This wet cake was again put into a dispersion tank, 90 parts by mass of deionized water was added, and a dispersion liquid was stirred and mixed while stirring with a dissolver for 30 minutes. This dispersion was filtered again with an omnipore membrane filter (maximum pore diameter 0.2 µm) to obtain a wet cake containing 5 parts by mass of organic fine particles 1 and 5 parts by mass of deionized water. The wet cake was vacuum-dried at 50°C to obtain organic fine particles 1 from which the activator was removed.

[Production of Optical Film 4] (Example 4)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 4 was produced in the same manner except that the surfactant removal treatment was performed by the following method.

<Treatment 4 for removing surfactant of organic fine particles 1>

To a liquid feed tank of a ceramic membrane filtration system (standard (M-1) tester, NGK Filltech Co., Ltd.) having a filter of a UF membrane having a pore diameter of 10 nm (fraction molecular weight 50,000), the organic fine particles 1 were obtained. , 25 parts by mass of the emulsion of the composite containing organic fine particles 1 and sodium laurate was added, and 75 parts by mass of deionized water were added to obtain an organic fine particle dispersion.

The dispersion liquid was concentrated to 25 parts by mass by circulating the dispersion liquid while operating the circulation pump, making the dispersion liquid flow rate in the filter 3 m/sec, and applying a pressure of 0.1 MPa to the dispersion liquid. After concentration, 75 parts by mass of deionized water was added to the liquid feeding tank, and the dispersion was concentrated until it became 25 parts by mass. The dispersion was spray-dried under the following conditions with a spray dryer manufactured by Sakamoto Kiken (model: atomizer take-up method, model number: TRS-3WK) (indicated as SD in the table below) as a spray dryer to dry organic fine particles.

Feed rate: 10mL/min

Atomizer rotation speed: 11000rpm

Air volume: 2㎥/min

Spray dryer slurry inlet temperature: 100℃

Polymer particle assembly outlet temperature: 50℃

[Production of Optical Film 5] (Example 5)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 5 was produced in the same manner except that the surfactant removal treatment was performed by the following method.

<Treatment 5 for removing surfactant of organic fine particles 1>

To a liquid feed tank of a ceramic membrane filtration system (standard (M-1) tester, NGK Filltech Co., Ltd.) having a filter of a UF membrane having a pore diameter of 10 nm (fraction molecular weight 50,000), the organic fine particles 1 were obtained. , 20 parts by mass of the emulsion of the composite containing the organic fine particles 1 and sodium laurate was added, and 80 parts by mass of ethanol were added to obtain a dispersion of organic fine particles.

The dispersion liquid was concentrated to 20 parts by mass by circulating the dispersion liquid while operating the circulation pump, making the dispersion liquid flow rate in the filter 3 m/sec, and applying a pressure of 0.2 MPa to the dispersion liquid. After concentration, 80 parts by mass of ethanol was added to the liquid feeding tank, and the dispersion was concentrated to 20 parts by mass. This dispersion was spray-dried under the following conditions with a spray dryer manufactured by Sakamoto Kiken (model: atomizer take-up method, model number: TRS-3WK) as a spray dryer to dry organic fine particles.

Feed rate: 10mL/min

Atomizer rotation speed: 11000rpm

Air volume: 2㎥/min

Spray dryer slurry inlet temperature: 100℃

Polymer particle assembly outlet temperature: 50℃

[Production of Optical Film 6] (Example 6)

Using the emulsion of the composite containing the organic fine particles 1 and sodium laurate obtained in the preparation of the optical film 1, except that the surfactant removal treatment and the preparation of the organic fine particle addition solution were performed in the following manner, the optical film 6 Was produced.

<Surface active agent removal treatment 6 of organic fine particles 1>

To a liquid feed tank of a ceramic membrane filtration system (standard (M-1) tester, NGK Filltech Co., Ltd.) having a filter of a UF membrane having a pore diameter of 10 nm (fraction molecular weight 50,000), the organic fine particles 1 were obtained. , 20 parts by mass of the emulsion of the composite containing the organic fine particles 1 and sodium laurate was added, and 80 parts by mass of ethanol were added to obtain an organic fine particle dispersion.

The dispersion liquid was concentrated to 20 parts by mass by circulating the dispersion liquid while operating the circulation pump, making the dispersion liquid flow rate in the filter 3 m/sec, and applying a pressure of 0.2 MPa to the dispersion liquid. After concentration, 80 parts by mass of ethanol was added to the liquid feeding tank, and the dispersion was concentrated to 20 parts by mass.

<Preparation of organic fine particle addition liquid>

After stirring and mixing the following materials for 50 minutes with a dissolver, dispersion was performed with 10,000 ton Gaulin. This was filtered with Finemet NM5P-2400 manufactured by Nippon Seisen Co., Ltd. to prepare an organic fine particle addition liquid having an organic fine particle content of 3.0% by mass.

The concentrated organic fine particle dispersion: 15 parts by mass

Dichloromethane: 85 parts by mass

[Production of Optical Film 7] (Example 7)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 7 was produced in the same manner as except having performed the surfactant removal treatment and the preparation of the organic fine particle addition liquid by the following method.

<Surface active agent removal treatment 7 of organic fine particles 1>

To a liquid feed tank of a ceramic membrane filtration system (standard (M-1) tester, NGK Filltech Co., Ltd.) having a filter of a UF membrane having a pore diameter of 10 nm (fraction molecular weight 50,000), the organic fine particles 1 were obtained. , 20 parts by mass of the emulsion of the composite containing the organic fine particles 1 and sodium laurate was added, and 80 parts by mass of ethanol were added to obtain an organic fine particle dispersion.

The dispersion liquid was concentrated to 20 parts by mass by circulating the dispersion liquid while operating the circulation pump, making the dispersion liquid flow rate in the filter 3 m/sec, and applying a pressure of 0.2 MPa to the dispersion liquid. After concentration, 80 parts by mass of ethanol was added to the liquid feeding tank, and the dispersion was concentrated to 20 parts by mass. After concentration, 80 parts by mass of dichloromethane was then added to the liquid feeding tank, and the dispersion was concentrated until 20 parts by mass, and this was repeated once more.

<Preparation of organic fine particle addition liquid>

After stirring and mixing the following materials for 50 minutes with a dissolver, dispersion was performed with 10,000 ton Gaulin. This was filtered with Finemet NM5P-2400 manufactured by Nippon Seisen Co., Ltd. to prepare an organic fine particle addition liquid having an organic fine particle content of 3.0% by mass.

The concentrated organic fine particle dispersion: 15 parts by mass

Dichloromethane: 85 parts by mass

[Production of Optical Film 8] (Example 8)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 8 was produced in the same manner except that the surfactant removal treatment was performed by the following method.

<Treatment 8 for removing surfactant of organic fine particles 1>

The organic fine particles 1 were heated at 120° C. for 24 hours to decompose and remove the surfactant.

[Production of Optical Film 9] (Example 9)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 9 was produced in the same manner except that the surfactant removal treatment was performed by the following method.

<Surface active agent removal treatment 9 of organic fine particles 1>

The organic fine particles 1 were aged at 60°C for 3 months to decompose and remove the surfactant.

[Production of Optical Film 10] (Example 10)

Using the organic fine particles 1 used in the production of the optical film 1, an optical film 10 was produced in the same manner except that a surfactant removal treatment was performed by the following method.

<Surface active agent removal treatment 10 of organic fine particles 1>

The organic fine particles 1 were subjected to moist heat treatment at 80°C and 90% RH for 24 hours to decompose and remove the surfactant.

[Production of Optical Film 11] (Example 11)

The preparation of the organic fine particle addition liquid in the said optical film 1 was changed as follows. Otherwise, it carried out similarly to the said optical film 1, and produced the optical film 11.

<Preparation of organic fine particle addition liquid>

The following materials were stirred and mixed in a tank for mixing organic fine particles with a dissolver for 50 minutes.

Organic fine particles before surfactant removal treatment 1: 3 parts by mass

Dichloromethane: 96 parts by mass

Deionized water: 1 part by mass

After mixing, by standing for 24 hours, dichloromethane and water are phase-separated to form an aqueous phase in the upper layer and a dichloromethane phase in the lower layer. Sodium lauryl sulfate, a surfactant, is soluble in water and is insoluble in dichloromethane, so it is extracted in the aqueous phase. When the mixed solution is taken out from the mixed solution outlet provided at the bottom of the mixing tank, 10 parts by mass of the mixed solution is left to be taken out, and the surfactant contained in the upper water phase is removed.

This mixed solution was placed in an organic fine particle dispersion tank and dispersed with 10,000 tonnes of Gaulin. This was filtered with Finemet NM5P-2400 manufactured by Nippon Seisen Co., Ltd. to prepare an organic fine particle addition liquid having an organic fine particle content of 3.0% by mass.

[Production of Optical Film 12] (Example 12)

In the preparation of the optical film 6, the optical film 12 was produced in the same manner as the polymer containing the alicyclic hydrocarbon monomer having a polar group was changed to the polymer containing the following (meth)acrylic monomer. In addition, the refractive index of the polymer containing the acrylic monomer was also measured by the same method as the method of measuring the refractive index of the organic fine particles described above.

Diamond BR85 (Mw=280000) (manufactured by Mitsubishi Chemical Co., Ltd.) (Ratio of molecular (meth)acrylic monomer in acrylic resin: 90% by mass or more)

[Production of Optical Film 13] (Comparative Example 1)

An optical film 13 was produced in the same manner as the organic fine particles 1 used in the production of the optical film 1 were not subjected to a surfactant removal treatment, but used as it was.

[Production of Optical Film 14] (Comparative Example 2)

In the production of the optical film 6, except having changed the organic fine particles 1 to the following organic fine particles 2, an optical film 14 was produced in the same manner.

<Production of seed particles>

To a polymerization reactor equipped with a stirrer and a thermometer, 1000 g of deionized water was put, 50 g of methyl methacrylate and 6 g of t-dodecylmercaptan were added thereto, and the mixture was heated to 70° C. with nitrogen substitution under stirring. The internal temperature was maintained at 70° C., and 20 g of deionized water in which 1 g of potassium persulfate was dissolved as a polymerization initiator was added, followed by polymerization for 10 hours. The average particle diameter of the seed particles in the obtained emulsion was 0.05 µm.

<Preparation of organic fine particles 2>

In a polymerization reactor equipped with a stirrer and thermometer, 650 g of deionized water dissolving 2.4 g of diglycerin monolaurate (Riken Vitamin Co., Ltd., Poem DL-100) as a surfactant was added, and 66 g of methyl methacrylate as a monomer mixture. , 20 g of styrene and 64 g of ethylene glycol dimethacrylate, and a mixture of 1 g of azobisisobutyronitrile as a polymerization initiator were added. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of an emulsion containing the seed particles was added and stirred at 30° C. for 2 hours to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 6 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), and polymer fine particles (organic fine particles 2) and diglycerin monolau adhering to the surface. A complex emulsion containing late (Riken Vitamin Co., Ltd., Poem DL-100) was obtained. The solid content concentration of the obtained organic fine particles 2 was 20%.

[Production of Optical Film 15] (Comparative Example 3)

In the production of the optical film 6, except having changed the organic fine particles 1 to the following organic fine particles 3, an optical film 15 was produced in the same manner.

<Production of seed particles>

To a polymerization reactor equipped with a stirrer and a thermometer, 1000 g of deionized water was put, 50 g of methyl methacrylate and 6 g of t-dodecylmercaptan were added thereto, and the mixture was heated to 70° C. with nitrogen substitution under stirring. The internal temperature was maintained at 70° C., and 20 g of deionized water in which 1 g of potassium persulfate was dissolved as a polymerization initiator was added, followed by polymerization for 10 hours. The average particle diameter of the seed particles in the obtained emulsion was 0.05 µm.

<Production of organic fine particles 3>

In a polymerization reactor equipped with a stirrer and thermometer, 650 g of deionized water dissolving 2.4 g of potassium fatty acid (Daiichi Kogyo Seiyaku Co., Ltd., DK Calisof GT) as a surfactant was added thereto, and 66 g of methyl methacrylate as a monomer mixture. , 20 g of styrene and 64 g of ethylene glycol dimethacrylate, and a mixture of 1 g of azobisisobutyronitrile as a polymerization initiator were added. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of an emulsion containing the seed particles was added and stirred at 30°C for 30 minutes to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 4 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), and polymer fine particles (organic fine particles 3), and fatty acid potassium adhering to the surface thereof (die Ichi Kogyo Seiyaku Co., Ltd., DK Calithorpe GT) was obtained. The solid content concentration of the obtained organic fine particles 3 was 20%.

[Production of Optical Film 16] (Comparative Example 4)

In the production of the optical film 11, except having changed the organic fine particles 1 to the following organic fine particles 4, an optical film 16 was produced in the same manner.

<Production of seed particles>

To a polymerization reactor equipped with a stirrer and a thermometer, 1000 g of deionized water was put, 50 g of methyl methacrylate and 6 g of t-dodecylmercaptan were added thereto, and the mixture was heated to 70° C. with nitrogen substitution under stirring. The internal temperature was maintained at 70° C., and 20 g of deionized water in which 1 g of potassium persulfate was dissolved as a polymerization initiator was added, followed by polymerization for 10 hours. The average particle diameter of the seed particles in the obtained emulsion was 0.05 µm.

<Production of organic fine particles 4>

In a polymerization reactor equipped with a stirrer and thermometer, 650 g of deionized water dissolving 2.4 g of a quaternary ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd., Catiogen TML) as a surfactant was added, and methyl methacrylate as a monomer mixture. A mixed solution of 66 g, 20 g of styrene and 64 g of ethylene glycol dimethacrylate, and 1 g of azobisisobutyronitrile as a polymerization initiator was added. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of an emulsion containing the seed particles was added and stirred at 30°C for 1 hour to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 5 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), and polymer fine particles (organic fine particles 4) and a quaternary ammonium salt attached to the surface ( Daiichi Kogyo Seiyaku Co., Ltd., an emulsion of a complex containing Catiogen TML) was obtained. The solid content concentration of the obtained organic fine particles 4 was 20%.

<Preparation of aggregate of organic fine particles 4>

The emulsion was spray-dried under the following conditions with a spray dryer manufactured by Sakamoto Kiken (model: atomizer take-up system, model number: TRS-3WK) as a spray dryer to obtain an aggregate of organic fine particles 4.

Feed rate: 25mL/min

Atomizer rotation speed: 11000rpm

Air volume: 2㎥/min

Spray dryer slurry inlet temperature: 100℃

Polymer particle assembly outlet temperature: 50℃

[Production of Optical Film 17] (Comparative Example 5)

In the production of the optical film 1, an optical film 17 was produced in the same manner except that the organic fine particles 1 were changed to the organic fine particles 5 below.

<Production of seed particles>

To a polymerization reactor equipped with a stirrer and a thermometer, 1000 g of deionized water was put, 50 g of methyl methacrylate and 6 g of t-dodecylmercaptan were added thereto, and the mixture was heated to 70° C. with nitrogen substitution under stirring. The internal temperature was maintained at 70° C., and 20 g of deionized water in which 1 g of potassium persulfate was dissolved as a polymerization initiator was added, followed by polymerization for 10 hours. The average particle diameter of the seed particles in the obtained emulsion was 0.05 µm.

<Preparation of organic fine particles 5>

In a polymerization reactor equipped with a stirrer and a thermometer, 650 g of deionized water dissolving 2.4 g of polyoxyethylene alkylphenyl ether (Daiichi Kogyo Seiyaku Co., Ltd. Neugen EA-87) as a surfactant was added thereto. A mixed solution of 66 g of methyl acrylate, 20 g of styrene and 64 g of ethylene glycol dimethacrylate, and 1 g of azobisisobutyronitrile as a polymerization initiator was added. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of the emulsion containing the seed particles was added and stirred at 30° C. for 3 hours to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 7 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), and polymer fine particles (organic fine particles 5) and polyoxyethylene alkyl adhering to the surface thereof. An emulsion of a complex containing phenyl ether (Daiichi Kogyo Seiyaku Co., Ltd. Neugen EA-87) was obtained. The solid content concentration of the obtained organic fine particles 5 was 20%.

<Preparation of aggregate of organic fine particles 5>

The emulsion was spray-dried under the following conditions with a spray dryer manufactured by Sakamoto Kiken (model: atomizer take-up system, model number: TRS-3WK) as a spray dryer to obtain an aggregate of organic fine particles 5.

Feed rate: 25mL/min

Atomizer rotation speed: 11000rpm

Air volume: 2㎥/min

Spray dryer slurry inlet temperature: 100℃

Polymer particle assembly outlet temperature: 50℃

[Production of Optical Film 18] (Comparative Example 6)

In the production of the optical film 8, except for changing the organic fine particles 1 to the organic fine particles 5, an optical film 18 was produced in the same manner.

[Production of Optical Film 19] (Comparative Example 7)

In the production of the optical film 6, except having changed the organic fine particles 1 to the following organic fine particles 7, the optical film 19 was produced in the same manner.

<Preparation of organic fine particles 7>

In a polymerization reactor equipped with a stirrer and thermometer, 650 g of deionized water in which 2.4 g of sodium lauryl sulfate was dissolved as a surfactant was added, 50 g of styrene and 100 g of ethylene glycol dimethacrylate as a monomer mixture, and azobisisobuty as a polymerization initiator. A mixture of 1 g of ronitrile was added. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of an emulsion containing the seed particles used in the preparation of the organic fine particles 1 was added, followed by stirring at 30°C for 1 hour to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 5 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), polymer fine particles (organic fine particles 7), and sodium laurate adhering to the surface. To obtain an emulsion of the composite containing. The solid content concentration of the obtained organic fine particles 7 was 20%.

[Production of Optical Film 20] (Comparative Example 8)

In the preparation of the optical film 6, except that the polymer containing the alicyclic hydrocarbon-based monomer having a polar group is changed to a cellulose triacetate (TAC) having a number average molecular weight of Mn 70000 having an acetyl group substitution degree of 2.80, Optical film 20 was produced.

[Production of Optical Film 21] (Example 13)

In the production of the optical film 6, except having changed the organic fine particles 1 to the following organic fine particles 13, an optical film 21 was produced in the same manner.

<Production of seed particles>

To a polymerization reactor equipped with a stirrer and a thermometer, 1000 g of deionized water was put, 50 g of methyl methacrylate and 6 g of t-dodecylmercaptan were added thereto, and the mixture was heated to 70° C. with nitrogen substitution under stirring. The internal temperature was maintained at 70° C., and 20 g of deionized water in which 1 g of potassium persulfate was dissolved as a polymerization initiator was added, followed by polymerization for 10 hours. The average particle diameter of the seed particles in the obtained emulsion was 0.05 µm.

<Production of organic fine particles 13>

In a polymerization reactor equipped with a stirrer and a thermometer, 650 g of deionized water dissolving 2.4 g of polyoxyethylene polyoxypropylene glycol (Epan 750, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a surfactant was added, and meta A mixed solution of 66 g of methyl acrylate, 20 g of styrene and 64 g of ethylene glycol dimethacrylate, and 1 g of azobisisobutyronitrile as a polymerization initiator was added. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of an emulsion containing the seed particles was added and stirred at 30°C for 1 hour to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 5 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), and polymer fine particles (organic fine particles 13) and polyoxyethylene poly adhering to the surface thereof. An emulsion of the complex containing oxypropylene glycol was obtained. The solid content concentration of the obtained organic fine particles 13 was 20%.

<Preparation of an aggregate of organic fine particles 13>

The emulsion was spray-dried under the following conditions with a spray dryer manufactured by Sakamoto Kiken (model: atomizer take-up method, model number: TRS-3WK) as a spray dryer to obtain an aggregate of organic fine particles 13.

Feed rate: 25mL/min

Atomizer rotation speed: 11000rpm

Air volume: 2㎥/min

Spray dryer slurry inlet temperature: 100℃

Polymer particle assembly outlet temperature: 50℃

[Production of Optical Film 22] (Example 14)

In the production of the optical film 6, except having changed the organic fine particles 1 to the following organic fine particles 14, an optical film 22 was produced in the same manner.

<Production of seed particles>

To a polymerization reactor equipped with a stirrer and a thermometer, 1000 g of deionized water was put, 50 g of methyl methacrylate and 6 g of t-dodecylmercaptan were added thereto, and the mixture was heated to 70° C. with nitrogen substitution under stirring. The internal temperature was maintained at 70° C., and 20 g of deionized water in which 1 g of potassium persulfate was dissolved as a polymerization initiator was added, followed by polymerization for 10 hours. The average particle diameter of the seed particles in the obtained emulsion was 0.05 µm.

<Production of organic fine particles 14>

In a polymerization reactor equipped with a stirrer and thermometer, 650 g of deionized water in which 2.4 g of sodium lauryl sulfate was dissolved as a surfactant was added, and 56 g of methyl methacrylate, 25 g of styrene and 69 g of ethylene glycol dimethacrylate were polymerized thereto as a monomer mixture. A mixed solution of 1 g of azobisisobutyronitrile was added as an initiator. Next, the mixture was stirred with a T.K homo mixer (manufactured by Tokushu Kika Kogyo) to obtain a dispersion.

To the obtained dispersion, 60 g of an emulsion containing the seed particles was added and stirred at 30°C for 1 hour to absorb the monomer mixture into the seed particles. Subsequently, the absorbed monomer mixture was polymerized by heating at 50° C. for 5 hours under a nitrogen stream, and then cooled to room temperature (about 25° C.), polymer fine particles (organic fine particles 14), and sodium laurate adhering to the surface. To obtain an emulsion of the composite containing. The solid content concentration of the obtained organic fine particles 14 was 20%.

[Production of Optical Film 23] (Example 15)

In the production of the organic fine particles 1 in the optical film 1, the amount of t-dodecylmercaptan, the polymerization temperature, and the stirring time were adjusted to produce organic fine particles 15 having an average particle diameter of 8 nm. Otherwise, it carried out similarly to the said optical film 6, and produced the optical film 23.

[Preparation of optical film 24] (Example 16)

In the preparation of the organic fine particles 1 in the optical film 1, the amount of t-dodecylmercaptan, the polymerization temperature, and the stirring time were adjusted to prepare organic fine particles 16 having an average particle diameter of 550 nm. Otherwise, it carried out similarly to the said optical film 6, and produced the optical film 24.

[Production of optical film 25] (Example 17)

In the preparation of the dope containing organic fine particles in the optical film 1, the composition of the dope was changed to the following. Otherwise, it carried out similarly to the said optical film 6, and produced the optical film 25.

(The composition of dope)

Polymer containing the alicyclic hydrocarbon monomer: 99.92 parts by mass

Dichloromethane: 250.0 parts by mass

Ethanol: 20.0 parts by mass

3 mass% organic fine particle addition liquid: 2.7 mass parts (fine particle weight: 0.08 mass parts)

The solid substance in the dope has a composition of a polymer (98.92 mass%) and organic fine particles (0.08 mass%) containing an alicyclic hydrocarbon monomer.

[Production of Optical Film 26] (Example 18)

Preparation of the organic fine particle addition liquid and preparation of the organic fine particle-containing dope in the said optical film 1 were changed as follows. Otherwise, it carried out similarly to the said optical film 6, and produced the optical film 26.

<Preparation of organic fine particle addition liquid>

After stirring and mixing the following materials for 50 minutes with a dissolver, dispersion was performed with 10,000 ton Gaulin. This was filtered with Nippon Seisen Co., Ltd. Finemet NM5P-2400 to prepare an organic fine particle addition liquid having an organic fine particle content of 20.0% by mass.

The organic fine particles 1: 20 parts by mass

Dichloromethane: 80 parts by mass

<Preparation of dope containing organic fine particles>

First, methylene chloride and ethanol were added to a pressure dissolution tank. Next, a polymer containing an alicyclic hydrocarbon monomer was added to the pressure dissolution tank while stirring, and a 20% by mass of the organic fine particle addition liquid was added to adjust the dope of the following composition. This was filtered at a filtration flow rate of 300 L/m 2·h and a filtration pressure of 1.0×10 ⁶ Pa using Azumi Rossi No. 244 (filtration accuracy 7 μm) manufactured by Azumi Rossi.

(The composition of dope)

Polymer containing the alicyclic hydrocarbon monomer: 78.0 parts by mass

Dichloromethane: 190.0 parts by mass

Ethanol: 20.0 parts by mass

20 mass% organic fine particle addition liquid: 110.0 mass parts (fine particle weight: 22.0 mass parts)

The solid substance in the dope has a composition of a polymer (78.0 mass%) and organic fine particles (22.0 mass%) containing an alicyclic hydrocarbon monomer.

[Measurement of Surfactant Content in Optical Film]

The obtained optical film was freeze-dried and pulverized, ultrasonically extracted with methanol, centrifuged, and dried to dry the methanol soluble component to measure the mass.

Thereafter, the dried solid was dissolved in heavy methanol to which 1,4-bis(trimethylsilyl)benzene-d4 was added as an internal standard, and the dissolved solution was NMR device: ECZ-400S (400 MHz manufactured by JEOL RESONANCE), It was measured under the following conditions, and the content of the surfactant was calculated from the strength of the proton derived from the structure of the surfactant and the strength of the internal standard, and is shown in the following table.

Observation nucleus: 1H

Pulse width: 5.6 μs (45° pulse)

Pulse delay time: 15s

Measurement integration count: 64 times

<Calculation of the difference in refractive index between organic fine particles and polymer>

For the organic fine particles and the polymer used in each optical film, the refractive index difference was calculated from the value of the refractive index measured above, and is shown in the following table.

[evaluation]

<Substrate contamination>

After the completion of film formation of each optical film, the surface of the flexible substrate (a stainless steel endless support) was visually observed, and the contamination condition was observed, and the contamination of the substrate was evaluated according to the following criteria.

◎: There is no contamination at all.

○: It is not normally seen by light source illumination, but contamination is seen when illuminated by green point light source illumination.

△: There is some contamination.

X: Contamination is conspicuous during film formation.

<Internal Haze>

A few drops of glycerin were dripped on both surfaces of each produced optical film, and it was sandwiched from both sides between two glass plates (micro slide glass part number S 9111, product made by MATSUNAMI) having a thickness of 1 mm. The optical film with both sides sandwiched between the glass plates is optically completely in close contact with the two glass plates, and in this state, haze (Ha) is conformed to JIS K-7136, and NDH-2000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.) ) Was used, and a 5V9W halogen sphere was used as the light source, and the light receiving portion was a silicon photocell (with a non-visible filter), and haze measurement was performed under conditions of 23°C and 55% RH. Then, only a few drops of glycerin were dripped and inserted between two glass plates, and the glass haze (Hb) was measured. Then, an internal haze value was calculated by subtracting the value of the glass haze (Hb) from the value of the haze (Ha).

In order to use it as an optical film, when the internal haze becomes larger than 0.1%, it is inferior from a transparency viewpoint, and it is not preferable. It is preferably 0.05% or less, and further preferably 0.02% or less.

<Friction>

(Measurement of kinetic friction coefficient μ)

Each produced optical film was slit 15 cm wide from both edges in the width direction to remove, and from the center portion in the width direction of the optical film after the slit, a test piece having a size of 80 mm in the winding direction x 200 mm in the width direction was cut out one by one. . According to JIS K7125 (1987), two test pieces were superimposed on a horizontal plane, and a weight of 200 g was placed thereon, and under the conditions of a moving speed of 100 mm/min and a contact area of 80 mm × 200 mm, the upper test piece was horizontally And the average load F on which the upper test piece is moving was measured, and the kinetic friction coefficient μ of both edge portions in the width direction of the optical film was obtained from the following equation, and is shown in the following table.

Coefficient of kinetic friction μ=F(g)/weight of weight (g)

When the kinetic friction coefficient μ was 0.7 or less, it was assumed that there was no problem in practical use.

<Polarizer adhesion>

(Manufacture of polarizer)

A 120 µm-thick polyvinyl alcohol film was uniaxially stretched (temperature 110° C., draw ratio 5 times). This was immersed for 60 seconds in an aqueous solution comprising 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water. Subsequently, it was immersed in an aqueous solution at 68° C. comprising 6 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. This was washed with water and dried to obtain a 5 µm-thick polarizer.

(Preparation of adhesive)

After mixing each of the following components, defoaming was performed to prepare an ultraviolet curable adhesive. In addition, triarylsulfonium hexafluorophosphate was used as a 50% by mass propylene carbonate solution, and in the following configuration, triarylsulfonium hexafluorophosphate was expressed as a solid content.

3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate: 45 parts by mass

Epolide GT-301 (Alicyclic epoxy resin manufactured by Daicel Chemical Co., Ltd.): 40 parts by mass

1,4-butanediol diglycidyl ether: 15 parts by mass

Triarylsulfoniumhexafluorophosphate: 2.3 parts by mass

9,10-dibutoxyanthracene: 0.1 parts by mass

1,4-diethoxynaphthalene: 2.0 parts by mass

(Manufacture of polarizing plate)

Corona discharge treatment was performed on the surface of the prepared optical film. In addition, conditions of the corona discharge treatment were made into a corona output strength of 2.0 kW and a line speed of 18 m/min. Subsequently, the prepared ultraviolet curable adhesive was applied to the corona discharge treatment surface of the polarizing plate protective film with a bar coater so that the cured film thickness became about 3 μm to form an ultraviolet curable adhesive layer. The produced polarizer was bonded to the obtained ultraviolet-curable adhesive layer.

Further, a corona discharge treatment was performed on Konica Minolta Tack KC2UA (thickness 25 μm, manufactured by Konica Minolta) under the same conditions as described above. Subsequently, on the corona discharge treatment surface of KC2UA, the prepared ultraviolet curable adhesive solution was applied with a bar coater so that the cured film thickness became about 3 μm to form an ultraviolet curable adhesive layer.

And, by bonding the ultraviolet-curable adhesive layer of the KC2UA and the polarizer to which the prepared optical film is bonded to one side, the prepared optical film/ultraviolet-curable adhesive layer/polarizer/ultraviolet curing adhesive layer/the laminated structure of the KC2UA A laminated product was obtained.

On both sides of the obtained laminate, using an ultraviolet irradiation device equipped with a belt conveyor (the lamp uses a D-bulb manufactured by Fusion UV Systems Co., Ltd.), ultraviolet rays were irradiated so that the accumulated light amount became 750 mJ/cm 2, and each ultraviolet curable adhesive layer was applied. It cured and obtained the polarizing plate.

About the adhesiveness of an optical film and a polarizer, it evaluated according to the following evaluation criteria.

(Double-circle): It does not peel at all.

(Circle): It peels a little, but the film breaks immediately.

?: Very resistant, but peeling somehow when peeling carefully and carefully.

X: It peels easily.

<Polarizer durability>

After exposing the polarizing plate obtained above to a humid heat environment for 500 hours under the conditions of 80°C and 90% RH, the polarizing plate was taken out, and the temperature and humidity were adjusted at 23°C and 55% RH for 24 hours. Then, the color fading of the polarizer was visually observed and observed, and the durability of the polarizer was evaluated according to the following criteria.

(Double-circle): No color tone change is seen in the polarizer.

(Circle): Although some discoloration is seen in a polarizer, it is good quality.

?: Discoloration is seen in the polarizer, but the quality is acceptable in practical use.

×: By irradiation of xenon light, almost no color of the polarizer remains.

As shown in the above results, the optical film of the present invention, compared with the optical film of the comparative example, does not deteriorate internal haze, has good transportability of the film, and can prevent peeling between the optical film and the polarizer when used as a polarizing plate. In addition, it can be seen that deterioration of the polarizer can be prevented under moist heat durability conditions.

10: liquid crystal display
30: liquid crystal cell
50: first polarizing plate
51: first polarizer
53: protective film (F1)
55: protective film (F2)
70: second polarizing plate
71: second polarizer
73: protective film (F3)
75: protective film (F4)
90: backlight

Claims (7)

It is an optical film containing organic fine particles, a polymer containing at least an alicyclic hydrocarbon monomer having a polar group or a polymer containing at least a (meth)acrylic monomer,
Contains a surfactant in the range of 0.01 to 1 ppm,
The organic fine particles contain a polymer containing at least a (meth)acrylic monomer,
Optical characterized in that the solubility in ethanol at 23°C of the surfactant is 0.2 to 10% by mass, solubility in dichloromethane is less than 7% by mass, and solubility in water is 7% by mass or more. film. The optical film according to claim 1, wherein the surfactant is an anionic surfactant. The optical film according to claim 1 or 2, wherein the difference in refractive index between the polymer containing the alicyclic hydrocarbon monomer having a polar group or the polymer containing the (meth)acrylic monomer and the organic fine particles is 0.01 or less. The optical film according to any one of claims 1 to 3, wherein the organic fine particles have an average particle diameter in the range of 10 to 500 nm. The optical film according to any one of claims 1 to 4, wherein the content of the organic fine particles is in a range of 0.1 to 20% by mass based on the total mass of the optical film. It is a manufacturing method of an optical film which manufactures the optical film in any one of Claims 1-5,
As the organic fine particles, a method for producing an optical film, wherein organic fine particles subjected to a treatment to remove a surfactant present around them are used. The method for producing an optical film according to claim 6, wherein organic fine particles in which the surfactant has been removed with alcohol in an emulsion after synthesis of the organic fine particles by emulsion polymerization are used.

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