JP2016033623A - Optical film and method for manufacturing the same, polarizing plate, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film that has low moisture permeability and excellent adhesiveness of a low moisture permeable layer and suppresses blisters of the low moisture permeable layer which occurs upon cutting the film, a method for manufacturing the optical film, and a polarizing plate and a liquid crystal display device using the optical film.SOLUTION: The optical film includes a base film, a first layer, and a second layer, in this order. The first layer is formed by curing a curable composition for forming the first layer, which comprises a compound having an ethylenically unsaturated double bond, and has an elastic modulus of 1.0 to 5.0 GPa. The second layer is formed by curing a curable composition for forming the second layer, which comprises at least one of a compound having a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond, and a compound having a fluorene ring and an ethylenically unsaturated double bond.SELECTED DRAWING: None

Description

  The present invention relates to an optical film, a manufacturing method thereof, a polarizing plate, and a liquid crystal display device.

  In recent years, liquid crystal display devices have been widely used for liquid crystal panels such as liquid crystal televisions, personal computers, mobile phones, and digital cameras. Usually, a liquid crystal display device has a liquid crystal panel member provided with polarizing plates on both sides of a liquid crystal cell, and display is performed by controlling light from the backlight member with the liquid crystal panel member. Here, the polarizing plate is composed of a polarizer and protective films on both sides thereof, and a general polarizer is obtained by dyeing a stretched polyvinyl alcohol (PVA) film with iodine or a dichroic dye to protect it. A cellulose ester film or the like is used as the film.

  Recent liquid crystal display devices are becoming more and more demanding, and the demands for durability are becoming stricter as the quality of the liquid crystal display devices increases. For example, when used in outdoor applications, stability against environmental changes is required, and the optical film such as the protective film for polarizing plate and the optical compensation film used in the liquid crystal display device also has dimensions and optical characteristics against temperature and humidity changes. It is required to suppress changes in

  Liquid crystal display devices are used not only in conventional indoor applications, but also in harsher environments such as outdoors, and for optical films placed on the outermost surface of liquid crystal display devices, performance that does not allow moisture to permeate is important. It has become. In TV applications that are becoming larger in size in recent years, this problem is also affected by the tendency of the glass of the liquid crystal cell to become thinner, warping tends to increase, and there is concern about the effect on light leakage after aging in a high temperature and high humidity environment.

Patent Document 1 describes an optical device in which a large amount of acrylic resin such as polymethyl methacrylate (PMMA) is added to cellulose ester for the purpose of providing an optical film having high transparency, low moisture absorption, high heat resistance, and high mechanical strength. A film is disclosed.
On the other hand, a film in which a coating layer is provided on a base film is also known. For example, Patent Document 2 contains a compound having a cyclic aliphatic hydrocarbon group and two or more ethylenically unsaturated double bonds in the molecule on a base film that is a cellulose acylate having a film thickness of 80 μm. A film provided with a coating layer formed from the composition is described.

  Patent Documents 3 to 5 describe a film having a substrate, an undercoat layer, and an overcoat layer in this order, and a layer having a specific elastic modulus as the undercoat layer.

International Publication No. 2009/047924 JP 2006-83225 A JP 2001-229737 A JP 2005-181548 A JP 2008-197670 A

  Small and medium-sized devices such as tablet PCs and mobile devices, which have been rapidly spreading in recent years, have high demands for thinning and space-saving in liquid crystal display devices. Therefore, it is strongly desired to solve the problem of light leakage after aging in a high-temperature and high-humidity environment. The occurrence of warping and light leakage of the liquid crystal cell of the liquid crystal display device is caused by the polarization of the front and back surfaces of the liquid crystal cell of the liquid crystal display device by absorbing and releasing moisture by the polarizing plate and the optical film that constitutes the polarizing plate. It is considered that the difference in shrinkage occurs in the plate, the balance is lost, the liquid crystal cell is warped, and the four corners and four sides of the liquid crystal cell come into contact with the casing and the members on the back side to cause light leakage. For this reason, improvements in humidity dependency and wet heat durability have been required for protective films for polarizing plates, but for drastic improvement, it is necessary to suppress the absorption and release of moisture due to environmental changes. In particular, the optical film on the outermost surface of the polarizing plate is required to further reduce moisture permeability.

In order to reduce the water vapor transmission rate of the optical film on the outermost surface of the polarizing plate, it is conceivable that the optical film has a structure in which a low moisture-permeable layer is coated on the base film.
However, many of the monomers for forming the low moisture permeable layer are sterically bulky, and acrylates generally used as monomers for forming a cured layer such as pentaerythritol tetra (meth) acrylate have been conventionally used. Since the hydrophobicity is higher than that of the monomer, it is difficult to secure the adhesion with the base film, and as a result, the evaluation result of the 100 mass test for evaluating the adhesion of the coating film is lowered.
Therefore, it is conceivable to improve the adhesion between the base film and the undercoat layer by chemical bonding by providing an undercoat layer between the base film and the low moisture permeable layer. It is expected that adhesion by mass test can be greatly improved.
However, for example, when a long polarizing plate is cut, punched, or cut out to process it into a size to be incorporated into a liquid crystal display device, “floating” occurs at the interface between the low moisture permeable layer and the undercoat layer. A new problem has emerged that arises.

  Although Patent Document 3 discloses that the evaluation result of the 100-mass test is good, it has not been studied for reducing the occurrence of “floating”. That is, “floating” occurs when a large force is locally applied in a short time, such as when cutting a film. On the other hand, the adhesion evaluation by the 100-mass test has a weak force when compared with cutting. However, they are different issues because they are intended to evaluate peeling when it covers a large area continuously.

In view of the situation as described above, the object of the present invention is to provide an optical film having low moisture permeability, excellent adhesion of the low moisture permeable layer, and suppressed floating of the low moisture permeable layer generated during cutting, and The manufacturing method is provided.
Another object of the present invention is to provide a polarizing plate using the optical film. Still another object of the present invention is to provide a liquid crystal display device with improved light leakage after a high temperature and high humidity environment.

  The problem to be solved by the present invention can be solved by the following means.

一般式（Ｉ）中、Ｌ、及びＬ１は各々独立に二価以上の連結基を表し、ｎは１〜３の整数を表す。

一般式（ＩＶ）中、Ｌ、及びＬ１は各々独立に単結合又は２価以上の連結基を表し、Ｌ２は水素原子、単結合又は２価以上の連結基を表す。
［１０］
上記第２層形成用硬化性組成物は、更にロジン化合物を含有する、［１］〜［９］のいずれか１項に記載の光学フィルム。
［１１］
偏光子と、上記偏光子の保護フィルムとして［１］〜［１０］のいずれか１項に記載の光学フィルムとを少なくとも１枚含む偏光板。
［１２］
液晶セルと、上記液晶セルの少なくとも一方の面に配置された［１１］に記載の偏光板とを含み、上記光学フィルムが最表層となるように配置された液晶表示装置。
［１３］
基材フィルムと、第１層と、第２層とをこの順に有する光学フィルムの製造方法であって、
上記基材フィルム上に、
エチレン性不飽和二重結合を有する化合物を含有する第１層形成用硬化性組成物を塗布し、硬化して、弾性率が１．０〜５．０ＧＰａである第１層を形成する工程と、
環状脂肪族炭化水素基とエチレン性不飽和二重結合とを有する化合物、及びフルオレン環とエチレン性不飽和二重結合とを有する化合物の少なくともいずれかを含有する第２層形成用硬化性組成物を塗布し、硬化して第２層を形成する工程と、を有する光学フィルムの製造方法。 [1]
An optical film having a base film, a first layer, and a second layer in this order,
The first layer is a layer formed by curing a curable composition for forming a first layer containing a compound having an ethylenically unsaturated double bond and having an elastic modulus of 1.0 to 5.0 GPa. ,
The second layer contains at least one of a compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond, and a compound having a fluorene ring and an ethylenically unsaturated double bond. An optical film, which is a layer formed by curing a curable composition for formation.
[2]
The said 1st layer forming curable composition is 30-99 for the compound which has the said ethylenically unsaturated double bond, when the total solid of the said 1st layer forming curable composition is 100 mass%. The optical film according to [1], which is contained by mass%.
[3]
When the total solid content of the second layer forming curable composition is 100% by mass, the cyclic aliphatic hydrocarbon group and the ethylenically unsaturated double bond are used. The optical film according to [1] or [2], containing 50 to 99% by mass of a compound having a fluorene ring and a compound having an ethylenically unsaturated double bond.
[4]
The said 1st layer forming curable composition is an optical film of any one of [1]-[3] which contains an elastomer further.
[5]
The optical film according to [4], wherein the elastomer is a polyurethane-based, acrylic-based, or polystyrene-based elastomer.
[6]
The compound according to any one of [1] to [5], wherein the compound having an ethylenically unsaturated double bond contained in the curable composition for forming a first layer has a molecular weight of 2000 or less. the film.
[7]
The compound having an ethylenically unsaturated double bond contained in the curable composition for forming the first layer according to any one of [1] to [6], wherein an acrylic equivalent is 200 or less. Optical film.
[8]
The optical film according to any one of [1] to [7], wherein the film thickness of the first layer is less than 1.0 μm.
[9]
The curable composition for forming the second layer contains a compound having a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond, and the cyclic aliphatic hydrocarbon group is represented by the following general formula (I) and The optical film according to any one of [1] to [8], which is a group represented by at least one of formula (IV).

In general formula (I), L and L1 each independently represent a divalent or higher valent linking group, and n represents an integer of 1 to 3.

In general formula (IV), L and L1 each independently represent a single bond or a divalent or higher linking group, and L2 represents a hydrogen atom, a single bond or a divalent or higher valent linking group.
[10]
The said 2nd layer forming curable composition is an optical film of any one of [1]-[9] which contains a rosin compound further.
[11]
A polarizing plate comprising at least one polarizer and the optical film according to any one of [1] to [10] as a protective film for the polarizer.
[12]
A liquid crystal display device comprising a liquid crystal cell and the polarizing plate according to [11] disposed on at least one surface of the liquid crystal cell, wherein the optical film is an outermost layer.
[13]
A method for producing an optical film having a base film, a first layer, and a second layer in this order,
On the base film,
Applying a curable composition for forming a first layer containing a compound having an ethylenically unsaturated double bond and curing to form a first layer having an elastic modulus of 1.0 to 5.0 GPa; ,
Curable composition for second layer formation containing at least one of a compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond and a compound having a fluorene ring and an ethylenically unsaturated double bond Applying and curing to form a second layer. An optical film manufacturing method comprising:

  According to the present invention, it is possible to provide an optical film having a low moisture permeability, excellent adhesion of a low moisture permeable layer, and a low moisture permeable layer that is prevented from floating during cutting, and a method for producing the same. By using the optical film of the present invention, it is possible to provide a liquid crystal display device in which the occurrence of light leakage after a high temperature and high humidity environment is suppressed.

It is a figure which shows the evaluation method of the float in the Example of this invention. It is a schematic diagram which shows the observation direction of a sample in evaluation of floating. It is sectional drawing which shows the float which generate | occur | produced in the sample.

Hereinafter, the present invention will be described in detail.
The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
“Acrylic resin” means a resin obtained by polymerizing methacrylic acid or a derivative of acrylic acid, and a resin containing the derivative. Further, when not particularly limited, “(meth) acrylate” represents acrylate and methacrylate, and “(meth) acryl” represents acryl and methacryl.
Furthermore, the “slow axis direction” of the film is the direction in which the refractive index is maximum in the film plane, and the “fast axis direction” means the direction orthogonal to the slow axis in the film plane. .

[Optical film]
The optical film of the present invention is an optical film having a base film, a first layer, and a second layer (also referred to as “low moisture-permeable layer”) in this order, and the first layer is ethylenically unsaturated. It is a layer formed by curing a curable composition for forming a first layer containing a compound having a double bond and having an elastic modulus of 1.0 to 5.0 GPa, and the second layer is a cyclic aliphatic carbonization Curing a curable composition for forming a second layer containing at least one of a compound having a hydrogen group and an ethylenically unsaturated double bond and a compound having a fluorene ring and an ethylenically unsaturated double bond; It is an optical film which is a layer to be formed.

(Water vapor transmission rate of optical film)
The optical film of the present invention preferably has a moisture permeability of 5.0 to 120 g / m ² / day. Here, the moisture permeability is a value after 24 hours at 40 ° C. and a relative humidity of 90% by the method of JIS Z-0208.
The moisture permeability of the optical film of the present invention is preferably 100 g / m ² / day or less, more preferably 90 g / m ² / day or less, and still more preferably 80 g / m ² / day or less. 70 g / m ² / day or less is particularly preferable. If the water vapor transmission rate is 120 g / m ² / day or less, light leakage due to warpage of the liquid crystal cell after the normal temperature and high humidity and high temperature and high humidity environment of the liquid crystal display device can be suppressed.

{First layer}
The first layer in the optical film is formed by curing a curable composition for forming a first layer containing a compound having an ethylenically unsaturated double bond, and has a modulus of elasticity of 1.0 to 5.0 GPa. It is.

(Elastic modulus of the first layer)
The elastic modulus of the first layer is 1.0 to 5.0 GPa, preferably 1.0 to 4.0 GPa, and more preferably 1.0 to 2.5 GPa. By making the elasticity modulus of a 1st layer into the said range, the float of the low moisture-permeable layer which generate | occur | produces at the time of an optical film cutting can be suppressed. In the present invention, the elastic modulus means the nanoindentation elastic modulus (Er), and the measurement method will be described in detail in the section of Examples. Details of the principle are described in Handbook of Micro / NanoTriology (CRC edited by BharatBhushan).

(Film thickness of the first layer)
The film thickness of the first layer is preferably less than 1.0 μm, more preferably 0.01 μm or more and 0.8 μm or less, and still more preferably 0.01 μm or more and 0.6 μm or less.

[Compound having an ethylenically unsaturated double bond]
The curable composition for forming the first layer contains a compound having an ethylenically unsaturated double bond.

  The compound having an ethylenically unsaturated double bond is preferably a (meth) acrylate compound, (meth) acrylic acid diesters of alkylene glycol, (meth) acrylic acid diesters of polyoxyalkylene glycol, polyvalent (Meth) acrylic acid diesters of alcohol, ethylene oxide or propylene oxide adduct (meth) acrylic acid diesters, epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, etc. it can.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. For example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO modified Tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate Rate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyurethane polyacrylate, polyester polyacrylate and caprolactone-modified tris (acryloyloxyethyl) isocyanurate.

  Commercially available polyfunctional acrylate compounds having a (meth) acryloyl group can be used, and NK ester A-TMMT, ATM-4E, A-200, Nippon Chemical Co., Ltd., manufactured by Shin-Nakamura Chemical Co., Ltd. KAYARAD DPHA manufactured by Yakuhin Co., Ltd., urethane acrylate UV-1700B manufactured by Nippon Synthetic Chemical Co., Ltd. can be exemplified. The polyfunctional monomer is described in paragraphs [0114] to [0122] of JP-A-2009-98658, and the same can be used in the present invention.

  The compound having an ethylenically unsaturated double bond contained in the curable composition for forming the first layer is a compound having a hydrogen bonding substituent, adhesion to the support, low curl, It is preferable from the viewpoint of fixability of the fluorine-containing or silicone-based compound described later. The hydrogen-bonding substituent refers to a substituent in which an atom such as nitrogen, oxygen, sulfur, or halogen and a hydrogen bond are bonded by a covalent bond, specifically, —OH, —SH, —NH—, —CHO. , -CONH-, -OCONH- and the like, and urethane (meth) acrylates and (meth) acrylates having a hydroxyl group are preferred. Commercially available polyfunctional acrylates having a (meth) acryloyl group can also be used. Shin Nakamura Chemical Co., Ltd. NK Oligo U4HA, NK Ester A-TMM-3, Nippon Kayaku Co., Ltd. KAYARAD PET-30 etc. can be mentioned.

The content of the compound having an ethylenically unsaturated double bond is preferably 30 to 99% by mass when the total solid content of the curable composition for forming a first layer is 100% by mass, More preferably, it is 90 mass%, and it is still more preferable that it is 50-80 mass%. Here, the total solid content of the curable composition refers to all components excluding the solvent from the curable composition.
The compounds having an ethylenically unsaturated double bond may be used alone or in combination of two or more. When using 2 or more types together, it is preferable that total content is the said range.

  The compound having an ethylenically unsaturated double bond is preferably a compound having a molecular weight of 2000 or less, and more preferably 200 or more and 1000 or less. When the molecular weight is 2000 or less, the base film is easily soaked when the first layer is formed, and the adhesion between the base film and the first layer can be improved.

The compound having an ethylenically unsaturated double bond contained in the curable composition for forming the first layer preferably has an acrylic equivalent of 200 or less, more preferably 70 or more and 150 or less. When the acrylic equivalent is 200 or less, the adhesion between the first layer and the second layer can be enhanced by the chemical bond between the first layer and the second layer.
The acrylic equivalent, acrylic equivalent of E _a, the molecular weight M, the number of acryloyl groups in the molecule when the N _a, is a value represented by the following formula.
E _a = M / N _a

[Elastomer]
The curable composition for forming the first layer preferably further contains an elastomer in addition to the compound having an ethylenically unsaturated double bond. By including an elastomer in the curable composition for forming the first layer, the elastic modulus of the first layer can be adjusted to a desired range.
The content of the elastomer is preferably 1 to 70% by mass and more preferably 5 to 60% by mass when the total solid content of the curable composition for forming the first layer is 100% by mass. More preferably, it is 10-50 mass%.
Examples of the elastomer include polystyrene, polydiene, polyisobutylene, acrylic, polyurethane, polyester, polyamide, fluorine, and silicone elastomers. As polystyrene-based elastomers, Asaprene T-411, Asaprene T-439, Tuftec H1501, Tuftec H1503, Tuftec M1273, Tuftech H1943, Tuftec P1500, Tufplen A, Tufplen 126S, manufactured by Kuraray Co., Ltd. Septon HG252, Septon S1001, Septon S2002, Septon S2006, Septon S2063, Septon S2104, Septon S4044, Septon S4099, Septon S8104, Hibler 5125, Hibler 5127, Hibler 7125, Hibler 7311, Zeof ZFT13t34t34t34t , Quintac 3390, JSR Corporation Examples include JSR SIS5002, JSR SIS5403, JSR TR1600, JSR TR2001, JSR TR2250, and the like. Examples of the polydiene elastomer include JSR BR01, JSR BR730, JSR RB810, JSR RB840, and JSR IR2200 manufactured by JSR. Examples of the polyisobutylene elastomer include Shibustar 062M, Shibster 062T, Shibster 072T, Shibster 073T, Shibster 102T, and Shibster 103T manufactured by Kaneka Corporation. Examples of the acrylic elastomer include Kane Ace B-546, Kane Ace FM-50, Kane Ace M-210, Kane Ace MP-90, Kane Ace MR-01, Zemlac YC3623, Zemlac YP1915B, Kuraray Clarity LA2140E, and Clarity. LA2250, Clarity LA2330, Clarity LA4285, Metablene C-223A, Metabrene C-323A, Methbrene S-2001, Methbrene S-2006, Methbrene S-2030, Methbrene S-2100, Methbrene W-450A, Methbrene W manufactured by Mitsubishi Rayon Co., Ltd. -5500 etc. can be mentioned. Examples of polyurethane-based elastomers include Byron UR-1350, Byron UR-1510, Byron UR-1700, Byron UR-2300, Byron UR-3200, Byron UR-3210, Byron UR-3260, Byron UR-6100 manufactured by Toyobo Co., Ltd. Byron UR-8200, Byron UR-8300, Byron UR-8700 and the like. As polyester-based elastomers, Toray DuPont's Hytrel 2751, Hytrel 3046, Hytrel 4001T-X04, SB654, Hytrel SC753, Toyobo's Perprene P30B, Perprene P70B, Perprene S1001, Perprene S9001, Mitsubishi Chemical Corporation Primalloy CP200, primalloy CP300, etc. can be mentioned. Examples of polyamide-based elastomers include UBESTA 3012U, UBESTA XPA 9040X1, manufactured by Ube Industries, Ltd., Glais E-200LV, Glais EH-620, manufactured by Toyobo. Examples of the fluorine-based elastomer include Dionon THV manufactured by Sumitomo 3M, Cefral Soft G150 manufactured by Central Glass, Daiel Thermoplastic T-530 manufactured by Daikin Industries. Examples of the silicone-based elastomer include a sill graft made by NUC. In particular, when 10% by mass of elastomer is added to the total solid content in the curable composition for forming the first layer, a type of elastomer that can reduce the elastic modulus of the first layer by 10% or more is used. It is preferable to do.
As the elastomer, polyurethane-based, acrylic-based, and polystyrene-based elastomers are preferable.
Specific examples include polyester urethane, a core shell made of a copolymer of MMA (methyl methacrylate) -BA (butyl acrylate), a block copolymer of MMA-BA, and a styrene / butadiene thermoplastic elastomer.

<Solvent>
The curable composition for forming a first layer in the present invention can contain a solvent. As the solvent, various solvents can be used in consideration of the solubility of the monomer, the drying property during coating, the dispersibility of the translucent particles, and the like. Examples of such organic solvents include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate, carbonic acid. Methyl ethyl, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, Methyl propionate, ethyl propionate, γ-ptyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-metho Siethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, methyl acetoacetate and other methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexyl Alcohol, isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, ethylene glycol ethyl ether, ethylene glycol isopropyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, ethyl carbitol, butyl carbitol , Hexane, heptane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, tolu Examples thereof include ene and xylene, and these can be used alone or in combination of two or more.

  Among the above solvents, it is preferable to use at least one of dimethyl carbonate, methyl acetate, ethyl acetate, methyl ethyl ketone, acetylacetone, and acetone, more preferably dimethyl carbonate or methyl acetate, and methyl acetate is used. It is particularly preferred.

  It is preferable to use a solvent so that the solid content concentration of the curable composition for forming the first layer is in the range of 1 to 50% by mass, more preferably 1 to 40% by mass, and still more preferably 1 to 30%. % By mass.

{Second layer (low moisture-permeable layer)}
The second layer in the optical film of the present invention contains at least one of a compound having a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond, and a compound having a fluorene ring and an ethylenically unsaturated double bond. It is a layer formed by curing the curable composition for forming a second layer.

[Compound having a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond]
A compound having a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond can function as a binder.
By using a compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond, low moisture permeability can be realized, and excellent adhesion between the first layer and other layers and the second layer can be achieved. Light leakage of the polarizing plate can be prevented.
Although details are not clear, by using a compound having a cycloaliphatic hydrocarbon group in the molecule, a hydrophobic cycloaliphatic hydrocarbon group is introduced into the second layer, and the molecule is made hydrophobic by making it hydrophobic. Can be prevented and moisture permeability can be reduced. Moreover, by having an ethylenically unsaturated double bond in the molecule, the crosslinking point density is increased and the diffusion path of water molecules in the second layer is restricted. Increasing the cross-linking point density also has the effect of relatively increasing the density of the cyclic aliphatic hydrocarbon group, making the inside of the second layer more hydrophobic, preventing the adsorption of water molecules, and reducing the moisture permeability. Conceivable.
In order to increase the crosslinking point density, the number of ethylenically unsaturated double bonds in the molecule is more preferably 2 or more.

The cyclic aliphatic hydrocarbon group is preferably a group derived from an alicyclic compound having 7 or more carbon atoms, more preferably a group derived from an alicyclic compound having 10 or more carbon atoms, and still more preferably Is a group derived from an alicyclic compound having 12 or more carbon atoms.
The cycloaliphatic hydrocarbon group is particularly preferably a group derived from a polycyclic compound such as bicyclic or tricyclic.
More preferably, the central skeleton of the compound described in the claims of JP-A No. 2006-215096, the central skeleton of the compound described in JP-A No. 2001-10999, or the skeleton of an adamantane derivative may be used.

  Specific examples of the cyclic aliphatic hydrocarbon group include a norbornane group, a tricyclodecane group, a tetracyclododecane group, a pentacyclopentadecane group, an adamantane group, and a diamantane group.

  As the cyclic aliphatic hydrocarbon group (including a linking group), a group represented by any one of the following general formulas (I) to (V) is preferable, and the following general formula (I), (II), or (IV) The group represented by general formula (I) or (IV) is more preferable.

  In general formula (I), L and L1 each independently represent a single bond or a divalent or higher valent linking group. n represents an integer of 1 to 3.

  In general formula (II), L and L1 each independently represent a single bond or a divalent or higher valent linking group. n represents an integer of 1 to 2.

  In general formula (III), L and L1 each independently represent a single bond or a divalent or higher valent linking group. n represents an integer of 1 to 2.

  In general formula (IV), L and L1 each independently represent a single bond or a divalent or higher linking group, and L2 represents a hydrogen atom, a single bond or a divalent or higher valent linking group.

In general formula (V), L and L1 each independently represent a single bond or a divalent or higher linking group.
As the divalent or higher linking group of L and L1, an alkylene group having 1 to 6 carbon atoms which may be substituted, an amide bond which may be substituted at the N position, and a urethane which may be substituted at the N position Examples include a bond, an ester bond, an oxycarbonyl group, an ether bond, and the like, and groups obtained by combining two or more thereof.

Examples of the ethylenically unsaturated double bond include polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group and —C (O) OCH═CH ₂ is preferred. More preferably, a compound containing two or more (meth) acryloyl groups in one molecule as exemplified by M-1 to M-4 below can be used.

  The compound having a cycloaliphatic hydrocarbon group and having two or more ethylenically unsaturated double bonds in the molecule has the above-described cycloaliphatic hydrocarbon group and group having an ethylenically unsaturated double bond. It is configured by bonding through a linking group.

These compounds include, for example, polyols such as diols and triols having the above cyclic aliphatic hydrocarbon groups, and carboxylic acids and carboxylic acid derivatives of compounds having (meth) acryloyl groups, vinyl groups, styryl groups, allyl groups, etc. It can be easily synthesized by a one-step or two-step reaction with an epoxy derivative, an isocyanate derivative or the like.
Preferably, compounds such as (meth) acrylic acid, (meth) acryloyl chloride, (meth) acrylic anhydride, glycidyl (meth) acrylate, and compounds described in WO2012 / 00316A (eg, 1,1-bis ( (Acryloxymethyl) ethyl isocyanate) can be synthesized by reacting with a polyol having the above cyclic aliphatic hydrocarbon group.

  Hereinafter, although the preferable specific example of the compound which has a cycloaliphatic hydrocarbon group and has an ethylenically unsaturated double bond is shown, this invention is not limited to these.

[Compound having a fluorene ring and an ethylenically unsaturated double bond]
A compound having a fluorene ring and an ethylenically unsaturated double bond that can be contained in the second layer can function as a binder. In addition, a compound having a fluorene ring and an ethylenically unsaturated double bond can function as a curing agent, and can improve the strength and scratch resistance of the coating film and at the same time impart low moisture permeability. be able to.
In order to increase the crosslinking point density, the number of ethylenically unsaturated double bonds in the molecule is more preferably 2 or more.

  The compound having a fluorene ring and an ethylenically unsaturated double bond is preferably represented by the following general formula (VI).

In formula (VI), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a monovalent substituent, and m, n, p and q are each independently 0 to 0 4 represents an integer, and at least one of R ¹ and R ² represents a monovalent organic group having an ethylenically unsaturated double bond.

  A preferred embodiment of the general formula (VI) as a compound having a fluorene skeleton and an ethylenically unsaturated double bond in the molecule is represented by the following general formula (VII).

In formula, R < ₇ >, R < ₈ > shows hydrogen or a methyl group, r, s shows the integer of 0-5.

The content of at least one of the compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond and the compound having a fluorene ring and an ethylenically unsaturated double bond is determined by the curing for forming the second layer. When the total solid content of the adhesive composition is 100% by mass, it is preferably 50 to 99% by mass, and from the viewpoint of the remarkable reduction in moisture permeability, it is more than 50% by mass and 99% by mass or less. More preferably, it is more preferably 55 to 95% by mass, and particularly preferably 60 to 90% by mass.
At least one of a compound having a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond and a compound having a fluorene ring and an ethylenically unsaturated double bond may be used alone, or 2 More than one species may be used in combination. When using 2 or more types together, it is preferable that total content is the said range.

[Compounds having an ethylenically unsaturated double bond not having a cyclic aliphatic hydrocarbon group and a fluorene ring]
In the curable composition for forming the second layer used in the present invention, a compound having an ethylenically unsaturated double bond that does not have a cyclic aliphatic hydrocarbon group and a fluorene ring in the molecule is impaired. Can be used in combination as long as no

  The compound having an ethylenically unsaturated double bond not having a cycloaliphatic hydrocarbon group and a fluorene ring is preferably a (meth) acrylate compound not having a cycloaliphatic hydrocarbon group and a fluorene ring, (Meth) acrylic acid diesters of alkylene glycol, (meth) acrylic acid diesters of polyoxyalkylene glycol, (meth) acrylic acid diesters of polyhydric alcohols, (meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts , Epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and the like.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. For example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO modified Tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate Rate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyurethane polyacrylate, polyester polyacrylate and caprolactone-modified tris (acryloyloxyethyl) isocyanurate.

  Commercially available polyfunctional acrylate compounds having a (meth) acryloyl group can be used, such as NK ester A-TMMT manufactured by Shin-Nakamura Chemical Co., Ltd., KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd. Can be mentioned. The polyfunctional monomer is described in paragraphs [0114] to [0122] of JP-A-2009-98658, and the same can be used in the present invention.

The compound having an ethylenically unsaturated double bond that does not have a cycloaliphatic hydrocarbon group is a compound having a hydrogen bondable substituent, adhesion to the support, low curl, It is preferable from the viewpoint of fixability of fluorine or silicone compounds. The hydrogen-bonding substituent refers to a substituent in which an atom such as nitrogen, oxygen, sulfur, or halogen and a hydrogen bond are bonded by a covalent bond, specifically, —OH, —SH, —NH—, —CHO. , -CONH-, -OCONH- and the like, and urethane (meth) acrylates and (meth) acrylates having a hydroxyl group are preferred. Commercially available polyfunctional acrylates having a (meth) acryloyl group can also be used. Shin Nakamura Chemical Co., Ltd. NK Oligo U4HA, NK Ester A-TMM-3, Nippon Kayaku Co., Ltd. KAYARAD PET-30 etc. can be mentioned.
Content in the case of containing the compound which has an ethylenically unsaturated double bond which does not have a cycloaliphatic hydrocarbon group and a fluorene ring is 100 mass of the total solid of the said curable composition for 2nd layer formation. % Is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, and still more preferably 3 to 15% by mass with respect to the total solid content.

[Rosin compound]
It is preferable that the curable composition for forming the second layer further contains a rosin compound.
Specifically, the rosin compound is preferably at least one selected from rosin, hydrogenated rosin (also referred to as hydrogenated rosin), acid-modified rosin and esterified rosin (also referred to as rosin ester).
Examples of the rosin include unmodified rosins such as tall oil rosin, gum rosin, and wood rosin mainly composed of a resin acid such as abietic acid, levopimaric acid, pastrinic acid, neoabietic acid, dehydroabietic acid, or dihydroabietic acid.
The hydrogenated rosin means a hydrogenated rosin. Examples include those containing a high content (for example, 50% by mass or more) of a tetrahydro compound such as tetrahydroabietic acid. Examples of acid-modified rosins include unsaturated acid-modified rosins in which unsaturated acids such as maleic acid, fumaric acid and acrylic acid have been added by Diels-Alder addition reaction, and more specifically, maleopimar in which maleic acid is added to rosin. Examples thereof include fumaropimaric acid added with acid and fumaric acid, acrylopimaric acid added with acrylic acid, and the like. Examples of esterified rosins include alkyl esters of rosin, glycerin esters obtained by esterifying rosin and glycerin, and pentaerythritol esters obtained by esterifying rosin and pentaerythritol.

Examples of the rosin ester include super ester E-720, super ester E-730-55, super ester E-650, super ester E-786-60, tamanol E-100, emulsion AM-1002, emulsion SE-50 (and above). All trade names, special rosin ester emulsion, manufactured by Arakawa Chemical Industries, Ltd.), Super Ester L, Super Ester A-18, Super Ester A-75, Super Ester A-100, Super Ester A-115, Super Ester A- 125, Superester T-125 (all trade names, special rosin esters, manufactured by Arakawa Chemical Industries, Ltd.) and the like.
As rosin esters, ester gum AAG, ester gum AAL, ester gum A, ester gum AAV, ester gum 105, ester gum HS, ester gum AT, ester gum H, ester gum HP, ester gum HD, Pencel A, Pencel AD, Pencel AZ, Pencel C, Pencel D-125, Pencel D-135, Pencel D-160, Pencel KK (all are trade names, rosin ester resins, manufactured by Arakawa Chemical Industries, Ltd.).

  Furthermore, other rosins include Longis R, Longes K-25, Longis K-80, Longes K-18 (all trade names, rosin derivatives, manufactured by Arakawa Chemical Industries, Ltd.) Pine Crystal KR-85, Pine Crystal KR-120, pine crystal KR-612, pine crystal KR-614, pine crystal KE-100, pine crystal KE-311, pine crystal KE-359, pine crystal KE-604, pine crystal 30PX, pine crystal D-6011, Pine Crystal D-6154, Pine Crystal D-6240, Pine Crystal KM-1500, Pine Crystal KM-1550 (all trade names, ultra-light color rosin derivatives, manufactured by Arakawa Chemical Industries, Ltd.), Aradym R-140, Aradym R-9 (All trade names, polymerized rosin, manufactured by Arakawa Chemical Co., Ltd.), Hyper Pale CH (all trade names, hydrogenated rosin, manufactured by Arakawa Chemical Co., Ltd.), beam set 101 (all trade names, rosin acrylate) And Arakawa Chemical Industries, Ltd.).

The acid value of the rosin compound is preferably 150 to 400 mgKOH / g, more preferably 200 to 400 mgKOH / g, and particularly preferably 280 to 400 mgKOH / g. When the substrate film is a cellulose acylate film, by controlling the acid value of the rosin compound within this range, a very good adhesion effect can be obtained while maintaining the moisture permeability reduction effect of the cured layer.
Examples of the rosin compound having an acid value in the above range include the above-mentioned acid-modified rosin. Particularly, a rosin compound obtained by adding maleic acid or fumaric acid by Diels-Alder reaction is preferably used in the present invention.
In the present invention, it is preferable to use a rosin compound that has been acid-modified and then hydrogenated. By performing the hydrogenation treatment, it is possible to prevent the remaining double bond of the rosin compound from being oxidized in the second layer and coloring the film.
The softening point of the rosin compound is preferably 70 to 170 ° C. When the softening point of the rosin compound is 70 ° C. or higher, the cured layer is not soft and has excellent blocking properties. When the softening point is less than 170 ° C., the solubility in a solvent can be maintained, and there is an advantage that the haze of the cured layer is difficult to increase.
In the present invention, the softening point of the rosin compound can be measured by the ring and ball method of JIS K-2531.
When the rosin compound is added, the content is preferably 1 to 50% by mass when the total solid content of the curable composition for forming the second layer is 100% by mass, and preferably 5 to 40%. The content is more preferably mass%, and further preferably 15-30 mass%.

[Inorganic layered compound]
In order to further reduce the moisture permeability of the second layer of the present invention, it is also preferable to disperse the inorganic layered compound in a binder that can be used for the second layer. Since the inorganic layered compound has a hydrophilic surface, it is preferably subjected to an organic treatment.

The inorganic layered compound is an inorganic compound having a structure in which unit crystal layers are laminated and exhibiting a property of swelling or cleaving by coordinating or absorbing a solvent between the layers. Examples of such inorganic compounds include swellable hydrous silicates such as smectite group clay minerals (montmorillonite, saponite, hectorite, etc.), palm curite group clay minerals, kaolinite group clay minerals, phyllosilicates (mica). Etc.). In addition, a synthetic inorganic layered compound is also preferably used. Examples of the synthetic inorganic layered compound include synthetic smectite (hectorite, saponite, stevensite, etc.), synthetic mica, etc., preferably smectite, montmorillonite, mica, montmorillonite, mica. Is more preferable. As an inorganic layered compound that can be used as a commercial product, MEB-3 (Synthetic mica aqueous dispersion manufactured by Corp Chemical Co., Ltd.), ME-100 (Synthetic mica manufactured by Corp Chemical Co., Ltd.), S1ME (manufactured by Corp Chemical Co., Ltd.) Synthetic mica), SWN (Synthetic smectite manufactured by Corp Chemical Co., Ltd.), SWF (Synthetic smectite manufactured by Corp Chemical Co., Ltd.), Kunipia F (Purified bentonite manufactured by Kunimine Chemical Co., Ltd.), Bengel (Purified by Hojun Co., Ltd.) Bentonite), Wengel HV (Purified bentonite manufactured by Hojung Co., Ltd.), Wenger FW (Purified bentonite manufactured by Hojun Co., Ltd.), Wenger Bright 11 (Purified bentonite manufactured by Hojun Co., Ltd.), Wenger Bright 23 (Purified manufactured by Hojun Co., Ltd.) Bentonite), Wenger Bright 25 (Hojung Co., Ltd.) Purification bentonite), Wenger A (HOJUN Co. purification bentonite), can be used Wenger 2M (HOJUN Co. purified bentonite) or the like.
Such inorganic layered compounds are preferably those obtained by subjecting these inorganic layered compounds to organic treatment.
Examples of the organic layered inorganic layered compound include the organic layered inorganic layered compounds described in JP-A-2012-234094, paragraphs 0038 to 0044.

[Polymerization initiator]
The composition containing a compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond in the molecule and / or a compound having a fluorene skeleton and an ethylenically unsaturated double bond in the molecule includes a polymerization initiator. It is preferable to contain. As the polymerization initiator, a photopolymerization initiator is preferable.
As photopolymerization initiators, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, Examples include fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, and coumarins. Specific examples, preferred embodiments, commercially available products, and the like of the photopolymerization initiator are described in paragraphs [0133] to [0151] of JP-A-2009-098658, and can be suitably used in the present invention as well. it can.

  “Latest UV Curing Technology” {Technical Information Association, Inc.} (1991), p. 159, and “UV Curing System” written by Kiyomi Kato (published by the General Technology Center in 1989), p. Various examples are also described in 65-148 and are useful in the present invention.

  Commercially available photocleavable photoradical polymerization initiators include “Irgacure 651”, “Irgacure 184”, “Irgacure 819”, “Irgacure 907” manufactured by BASF (formerly Ciba Specialty Chemicals), “Irgacure 1870” (CGI-403 / Irgacure 184 = 7/3 mixed initiator), “Irgacure 500”, “Irgacure 369”, “Irgacure 1173”, “Irgacure 2959”, “Irgacure 4265”, “Irgacure 4263”, “Irgacure 127”, “OXE01”, etc .; “Kaya Cure DETX-S”, “Kaya Cure BP-100”, “Kaya Cure BDK”, “Kaya Cure BTX”, “Kaya Cure BMS”, “Kaya Cure 2” manufactured by Nippon Kayaku Co., Ltd. -EAQ "," Kayaki " “AraQ”, “Kayacure CPTX”, “Kayacure EPD”, “Kayacure ITX”, “Kayacure QTX”, “Kayacure BTC”, “Kayacure MCA”, etc .; “Esacure (KIP100F, KB1, EB3, BP, BP, manufactured by Sartomer) X33, KTO46, KT37, KIP150, TZT) "and the like, and combinations thereof are preferable examples.

  In a composition containing a compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond in the molecule and / or a compound having a fluorene skeleton and an ethylenically unsaturated double bond in the molecule used in the present invention The content of the photopolymerization initiator is polymerized from the polymerizable compound contained in the composition, and is set so that the starting point does not increase too much, with respect to the total solid content in the composition, 0.5-8 mass% is preferable and 1-5 mass% is more preferable.

[Ultraviolet absorber]
The optical film of the present invention including the second layer is used for a polarizing plate or a liquid crystal display device member, but from the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal, by containing an ultraviolet absorber in the second layer, It is also possible to impart ultraviolet absorptivity to the optical film.
A well-known thing can be used as a ultraviolet absorber. For example, the ultraviolet absorber as described in Unexamined-Japanese-Patent No. 2001-72782 and Special Table 2002-543265 is mentioned. Specific examples and preferred examples of the ultraviolet absorber include those similar to the specific examples and preferred examples of the ultraviolet absorber described later in the section of {Substrate film} <ultraviolet absorber>.

[solvent]
The composition for 2nd layer formation in this invention can contain a solvent. As the solvent, various solvents similar to the curable composition for forming the first layer can be used.

  It is preferable to use a solvent such that the solid content of the curable composition for forming the second layer is in the range of 20 to 80% by mass, more preferably 30 to 75% by mass, and still more preferably 40 to 40% by mass. 70% by mass.

(Film thickness of the second layer)
The film thickness of the second layer (low moisture permeable layer) is preferably 0.5 to 25 μm, more preferably 1 to 20 μm, further preferably 2 to 18 μm, and 3 to 17 μm. It is particularly preferred.

(Water permeability of the second layer)
From the gas transmission type of the composite film (e.g., "barrier of Science of the packaging material (packaging Fundamental Course 5)" p68~72 Tsutomu Nakagawa al Japan Packaging Institute), the moisture permeability of the optical film of the steady state J _f, group The moisture permeability of the laminate of the material film and the first layer is J _s , and the moisture permeability of the second layer when the optical film is separated into the laminate of the base film and the first layer and the second layer is when a J _b, the following equation holds.
1 / J _f = 1 / J _s + 1 / J _b (1)
The moisture permeability J _f of the optical film and the moisture permeability J _s of the laminate of the base film and the first layer can be directly measured, and the moisture permeability J _b of the second layer is calculated based on those measured values. Can be obtained.
In the present invention, the moisture permeability of the second layer is preferably 5.0 to 120 g / m ² / day.

(Moisture permeability per unit film thickness of the second layer)
It is generally known that the moisture permeability in a steady state is inversely proportional to the film thickness. Accordingly, the moisture permeability that the second layer can reach within the above-mentioned film thickness range is determined by the moisture permeability per unit film thickness, which is a characteristic value of the material. The smaller the value, the lower the moisture permeability. On the other hand, the moisture permeability can be adjusted by adjusting the film thickness of the second layer based on the above relationship, but if the moisture permeability per unit film thickness is too low, it becomes difficult to control the moisture permeability of the optical film.
In view of both moisture permeability per thickness 10μm of the second layer is preferably 5.0~120g ^/ m 2 ^/ day, more preferably ^{10~120g / m 2 / day, 20~100g} / m 2 / Day is more preferable, and 30 to 80 g / m ² / day is particularly preferable.
(The moisture permeability is a value after 24 hours at 40 ° C. and 90% relative humidity by the method of JIS Z-0208.)
The moisture permeability per 10 μm of the thickness of the second layer is estimated as follows from the moisture permeability of the laminate of the base film and the first layer, the moisture permeability of the optical film, and the thickness of the second layer.

The moisture permeability C _b (10 μm) for the film thickness of the second layer of 10 μm can be expressed by the following formula based on J _b calculated above.
C _b (10 μm) = J _b × d _b / 10 [g / m ² / day] (2)
(Here, d _b [μm] is the film thickness of the second layer, and can be determined from the film thickness difference before and after the second layer lamination as described above.)

  The second layer of the optical film of the present invention preferably has a moisture permeable hard coat layer function, an antireflection function, an antifouling function, and the like.

{Base film}
[Material of base film]
As a material for forming the base film, a polymer excellent in optical performance transparency, mechanical strength, thermal stability, isotropy and the like is preferable. The term “transparent” as used in the present invention indicates that the visible light transmittance is 60% or more, preferably 80% or more, and particularly preferably 90% or more. Examples include polycarbonate polymers, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, (meth) acrylic polymers such as polymethyl methacrylate, and styrene polymers such as polystyrene and acrylonitrile / styrene copolymers (AS resin). It is done. Polyolefins such as polyethylene and polypropylene, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers, polyethersulfone polymers Examples thereof include polyether ether ketone polymers, polyphenylene sulfide polymers, vinylidene chloride polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, and polymers obtained by mixing the above polymers. The polymer film of the present invention can also be formed as a cured layer of an ultraviolet-curable or thermosetting resin such as acrylic, urethane, acrylic urethane, epoxy, or silicone.

  In addition, as a material for forming the base film, a cellulose polymer (particularly preferably, cellulose acylate) represented by triacetyl cellulose, which has been conventionally used as a transparent protective film of a polarizing plate, is preferably used. it can. Moreover, it can use preferably also for the acrylic-type film which introduction | transduction is proposed as a polarizing plate protective film in recent years. Hereinafter, as an example of the base film of the present invention, cellulose acylate and (meth) acrylic polymer are mainly described in detail, but the technical matters can be similarly applied to other polymer films.

[Substitution degree of cellulose acylate]
Next, the cellulose acylate produced from the above cellulose will be described. Cellulose acylate is obtained by acylating a hydroxyl group of cellulose, and the substituent can be any acetyl group having 2 carbon atoms in the acyl group to those having 22 carbon atoms. In the cellulose acylate used as the material for the base film, the substitution degree of the acyl group to the hydroxyl group of cellulose is not particularly limited, but acetic acid and / or carboxylic acid having 3 to 22 carbon atoms for acylating the hydroxyl group of cellulose. The degree of substitution can be measured and the degree of substitution can be obtained by calculation. As a measuring method, it can carry out according to ASTM D-817-91.

  Although the substitution degree of the acyl group to the hydroxyl group of cellulose is not particularly limited, it is preferably 2.50 to 3.00, more preferably 2.75 to 3.00, and 2.85 to 3.00. More preferably.

  Acetic acid and / or carboxylic acid having 3 to 22 carbon atoms for acylating the hydroxyl group of cellulose may be an aliphatic carboxylic acid or an aromatic carboxylic acid, and may be a single or a mixture of two or more. Examples of the cellulose ester acylated by these include alkylcarbonyl ester, alkenylcarbonyl ester, aromatic carbonyl ester, aromatic alkylcarbonyl ester and the like of cellulose, and each may further have a substituted group. Preferred acyl groups include acetyl, propionyl, n-butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, and octadecanoyl. , Iso-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like. Among these, acetyl group, propionyl group, butanoyl group, dodecanoyl group, octadecanoyl group, t-butanoyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like are preferable, and acetyl group, propionyl group, n -A butanoyl group is more preferred.

<Cellulose acylate base film>
[Degree of polymerization of cellulose acylate]
The degree of polymerization of cellulose acylate preferably used in the present invention is 180 to 700 in terms of viscosity average polymerization degree, and in cellulose acetate, 180 to 550 is more preferable, 180 to 400 is more preferable, and 180 to 350 is particularly preferable. .

  The base film is preferably a (meth) acrylic polymer, and a (meth) acrylic polymer having at least one of a lactone ring structure, a glutaric anhydride ring structure, and a glutarimide ring structure in the main chain. It is more preferable that

  The (meth) acrylic polymer is a concept including both a methacrylic polymer and an acrylic polymer. The (meth) acrylic polymer also includes acrylate / methacrylate derivatives, particularly acrylate / methacrylate (co) polymers.

<(Meth) acrylic polymer>
The base film is also preferably formed from a (meth) acrylic polymer.

  The (meth) acrylic polymer preferably used in the present invention has a repeating structural unit derived from a (meth) acrylic acid ester monomer as a repeating structural unit in the main chain. It may have at least one of a glutaric acid ring structure and a glutarimide ring structure.

  The (meth) acrylic polymer is obtained by polymerizing at least one selected from a hydroxyl group-containing monomer, an unsaturated carboxylic acid, and a monomer represented by the following general formula (201) as a repeating structural unit. The repeating structural unit may be included.

General formula (201)
^{_{CH 2 = C (X) R}} 201
In the formula, R ²⁰¹ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, a —CN group, a —CO—R ²⁰² group, or —O—CO—R ^203. R ²⁰² and R ²⁰³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.

Although it does not specifically limit as (meth) acrylic acid ester, For example, acrylics, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, benzyl acrylate, etc. Acid esters; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate; May be used alone or in combination of two or more. Among these, methyl methacrylate is particularly preferable from the viewpoint of excellent heat resistance and transparency.
When (meth) acrylic acid ester is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 10 to 100% by mass, more preferably 10 to 10%, in order to sufficiently exhibit the effects of the present invention. 100 mass%, More preferably, it is 40-100 mass%, Most preferably, it is 50-100 mass%.

Examples of the hydroxyl group-containing monomer include α-hydroxymethyl styrene, α-hydroxyethyl styrene, 2- (hydroxyethyl) acrylic acid ester such as methyl 2- (hydroxyethyl) acrylate; 2- (hydroxyethyl) acrylic acid, and the like. 2- (hydroxyalkyl) acrylic acid; and the like. These may be used alone or in combination of two or more.
In the case of using a hydroxyl group-containing monomer, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass, more preferably 0 to 20%, in order to sufficiently exhibit the effects of the present invention. It is 0 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. These may be used alone or in combination of two or more. May be. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.
When using an unsaturated carboxylic acid, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, in order to sufficiently exhibit the effects of the present invention. %, More preferably 0 to 15% by mass, particularly preferably 0 to 10% by mass.

Examples of the monomer represented by the general formula (201) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, and vinyl acetate. These are used alone. Or two or more of them may be used in combination. Among these, styrene and α-methylstyrene are particularly preferable in that the effects of the present invention are sufficiently exhibited.
When the monomer represented by the general formula (201) is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass in order to sufficiently exhibit the effects of the present invention. More preferably, it is 0-20 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

[(Meth) acrylic polymer having a ring structure in the main chain]
Among (meth) acrylic polymers, those having a ring structure in the main chain are preferred. By introducing a ring structure into the main chain, the rigidity of the main chain can be improved and the heat resistance can be improved.
Among (meth) acrylic polymers having a ring structure in the main chain, a polymer having a lactone ring structure in the main chain, a polymer having a glutaric anhydride ring structure in the main chain, and a polymer having a glutarimide ring structure in the main chain It is preferably any one of coalesces. Among them, a polymer that forms a lactone ring structure in the main chain is more preferable.
The following polymers having a ring structure in these main chains will be described in order.

((Meth) acrylic polymer with lactone ring structure in the main chain)
A (meth) acrylic polymer having a lactone ring structure in the main chain (hereinafter also referred to as a lactone ring-containing polymer) is a (meth) acrylic polymer having a lactone ring in the main chain, and Japanese Patent Application Laid-Open No. 2006-096960, Resins described in JP 2007-066351 A can be used.

(Polymer having glutaric anhydride ring structure in the main chain)
The polymer having a glutaric anhydride ring structure in the main chain is a polymer having a glutaric anhydride unit, and uses a resin described in JP 2009-210905 A, JP 2009-030001 A, or the like. be able to.

((Meth) acrylic polymer with glutarimide ring structure in the main chain)
A (meth) acrylic polymer having a glutarimide ring structure in the main chain (hereinafter also referred to as a glutarimide resin) has a desirable balance of properties in terms of optical properties and heat resistance by having a glutarimide ring structure in the main chain. It can be expressed.

  The glutarimide resin is described in US Pat. No. 3,284,425, US Pat. No. 4,246,374, JP-A-2-153904, and the like, and is obtained by using methyl methacrylate as a main raw material as a resin having an imidizable unit. The resin can be obtained by imidizing a resin having a unit capable of imidization with ammonia or a substituted amine.

[Ultraviolet absorber]
The ultraviolet absorber preferably used for the substrate film will be described. The optical film of the present invention including the base film is used for a polarizing plate or a liquid crystal display member, and an ultraviolet absorber is preferably used from the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Only one type of ultraviolet absorber may be used, or two or more types may be used in combination. For example, the ultraviolet absorber as described in Unexamined-Japanese-Patent No. 2001-72782 and Special Table 2002-543265 is mentioned. Specific examples of the ultraviolet absorber include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

  Among them, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole, 2- (2′- Hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2 '-Hydroxy-3'-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3 -Tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy-3'-tert-butyl-5'-methyl) Enyl) -5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy) -5-benzoylphenylmethane), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2 '-Hydroxy-3', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzo Triazole, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1 , 3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4- Hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl) -4-hydroxybenzyl) -isocyanurate and the like. In particular, (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2′-hydroxy-3 ′, 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzotriazole, 2,6-di -Tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl -5-methyl-4-hydroxyphenyl) propionate], for example, N, N'-bis [3- (3,5-di-tert-butyl-4 Hydroxyphenyl) may be used in combination with phosphorus-based processing stabilizer such as metal hydrazine systems such as propionyl] hydrazine deactivator and tris (2,4-di -tert- butylphenyl) phosphite.

  An ultraviolet absorber can also be introduce | transduced into resin as a structural unit which has an ultraviolet absorptivity. For example, a benzotriazole derivative, a triazine derivative or a benzophenone derivative into which a polymerizable group is introduced. The polymerizable group to be introduced can be appropriately selected according to the structural unit of the resin.

  Specific examples of the monomer include 2- (2′-hydroxy-5′-methacryloyloxy) ethylphenyl-2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd., trade name RUVA-93), 2- (2′-hydroxy-5) '-Methacryloyloxy) phenyl-2H-benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methacryloyloxy) phenyl-2H-benzotriazole.

[Other additives]
To the base film, additives such as a matting agent, a retardation developing agent, a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a release agent, an infrared absorber, and a wavelength dispersion adjusting agent can be added. However, it may be an oily substance. That is, the melting point and boiling point are not particularly limited. For example, mixing of ultraviolet absorbing material at 20 ° C. or lower and 20 ° C. or higher, and similarly, mixing of a plasticizer is described in, for example, JP-A-2001-151901. Furthermore, infrared absorbing dyes are described in, for example, JP-A-2001-194522. Moreover, the addition time may be added at any time in the dope preparation step, but may be added by adding an additive to the final preparation step of the dope preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when an optical film is formed from a multilayer, the kind and addition amount of the additive of each layer may differ. For example, although it describes in Unexamined-Japanese-Patent No. 2001-151902 etc., these are techniques conventionally known. For these details, materials described in detail on pages 16 to 22 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used.

  The base film may contain rubber-like particles. Examples thereof include acrylic particles such as a soft acrylic resin, acrylic rubber, and rubber-acrylic graft type core-shell polymer, or styrene-elastomer copolymers. Furthermore, additives that improve impact resistance and stress whitening resistance described in JP-B-60-17406, JP-B-3-39095 and the like are also preferably used.

In the said base film, when adding these additives, it is preferable that the total amount of an additive is 50 mass% or less with respect to a base film, and it is preferable that it is 30 mass% or less.
These additives improve the brittleness of the film and greatly improve the folding resistance test of the film (e.g., crack evaluation when bent 180 degrees).
In order to achieve low haze, the refractive index of the additive preferably has substantially the same refractive index as the base film, and the refractive index difference is preferably 0.5 or less, more preferably 0.3 or less. preferable.

<Characteristics of base film>
(Base film thickness)
The film thickness of the substrate film is preferably 5 to 100 μm, more preferably 10 to 80 μm, particularly preferably 15 to 70 μm, and particularly preferably 20 to 60 μm. By controlling the film thickness within the above range, it is possible to reduce the environment in which the liquid crystal display device is placed after the second layer is stacked, that is, the unevenness of the panel due to temperature and humidity changes.

(Water vapor permeability of base film)
The moisture permeability of the base film is measured under conditions of 40 ° C. and 90% relative humidity based on JIS Z-0208.
The moisture permeability of the substrate film is preferably 300 g / m ² / day or less, more preferably 250 g / m ² / day or less, still more preferably 200 g / m ² / day or less, It is especially preferable that it is 150 g / m ² / day or less. By controlling the moisture permeability of the base film within the above range, the liquid crystal display device equipped with the optical film of the present invention in which the first layer and the second layer are stacked is subjected to normal temperature, high humidity and high temperature and high humidity environment over time. Liquid crystal cell warpage and light leakage can be suppressed.

(Moisture permeability per unit film thickness of base film)
As described in the second layer (moisture permeability per unit film thickness), the moisture permeability of the base film 10 μm is given by the following equation.
C _s (10 μm) = J _s × d _s / 10 [g / m ² / day]
(Here, d _s [μm] is the film thickness of the base film, and J _s is the moisture permeability of the base film.)
Moisture permeability is preferably 50~2000g ^/ m 2 ^/ day film thickness of the substrate film for 10 [mu] m, more preferably 80~1500g ^/ m 2 ^/ day, more preferably 100~1000g ^/ m 2 ^/ day, 150~800g / M ² / day is particularly preferred.
(The moisture permeability is a value after 24 hours at 40 ° C. and 90% relative humidity by the method of JIS Z-0208.)
A sufficient low moisture permeability effect is obtained above the lower limit, and curling can be suppressed below the upper limit.

(Oxygen permeability coefficient of base film)
In order to reduce moisture permeability, it is preferable to suppress the diffusion of water in the film, that is, it is preferable to reduce the free volume of the film. In general, the free volume of the film correlates with the oxygen permeability coefficient of the film.
The oxygen permeability coefficient of the base film is preferably 100 cc · mm / (m ² · day · atm) or less, and more preferably 30 cc · mm / (m ² · day · atm) or less.

(Equilibrium moisture content of base film)
The water content (equilibrium water content) of the base film is 25, regardless of the film thickness, so as not to impair the adhesion with water-soluble thermoplastics such as polyvinyl alcohol when used as a protective film for polarizing plates. It is preferable that the moisture content in 0 degreeC and 80% of relative humidity is 0-4 mass%. It is more preferably 0 to 2.5% by mass, and still more preferably 0 to 1.5% by mass. If the equilibrium moisture content is 4% by mass or less, the dependence of retardation on humidity changes does not increase too much, and the liquid crystal display device also has the effect of suppressing light leakage after normal temperature, high humidity and high temperature and high humidity environments. preferable.
The moisture content was measured using a film sample 7 mm × 35 mm with a moisture meter, a sample drying apparatus “CA-03” and “VA-05” (both manufactured by Mitsubishi Chemical Corporation) by the Karl Fischer method. ) Can be obtained by dividing the moisture content (g) by the sample mass (g).

(Dimensional change of base film)
The dimensional stability of the base film is as follows: dimensional change rate after standing for 24 hours under conditions of 60 ° C. and relative humidity 90% (high humidity), and 80 ° C., DRY environment (relative humidity 5% or less) ) When it is allowed to stand for 24 hours under the conditions (high temperature), it is preferable that the dimensional change rate is 0.5% or less. More preferably, it is 0.3% or less, More preferably, it is 0.15% or less.

<Method for producing base film>
The method for producing the base film includes a step of casting a polymer solution containing a thermoplastic resin and a solvent on a support to form a polymer film (the base film), or a process for melting a thermoplastic resin. It is preferable to include a step of forming a base film by forming a film. That is, the base film is preferably formed by casting a polymer solution containing the thermoplastic resin and a solvent on a support, or by melt-forming a thermoplastic resin. More preferably, a thermoplastic resin is melt-formed.

(surface treatment)
The base film can achieve improved adhesion between the base film and the first layer or other layers (for example, a polarizer, an undercoat layer, and a back layer) by optionally performing a surface treatment. . For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs in a low pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferable. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Details of these are described in detail on pages 30 to 32 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention), and are preferably used in the present invention. be able to.

{Function layer}
The optical film of the present invention has the first layer (adhesion layer) and the second layer (low moisture-permeable layer), and a functional layer may be further laminated on at least one surface. The type of the functional layer is not particularly limited, but a hard coat layer, an antireflection layer (a layer having a adjusted refractive index such as a low refractive index layer, a medium refractive index layer, or a high refractive index layer), an antiglare layer, an antistatic layer, Examples include an ultraviolet absorbing layer.
The functional layer may be a single layer or a plurality of layers. The method for laminating the functional layers is not particularly limited.
The functional layer may be laminated on the surface of the base film provided with the second layer. In this case, the functional layer may or may not be in contact with the second layer. Moreover, you may laminate | stack on the surface which has not laminated | stacked the 2nd layer. When laminating a plurality of functional layers, one functional layer may be laminated on the second layer, and the other functional layer may be laminated on the surface where the second layer is not laminated. In particular, it is preferable to coat and provide another functional layer on the optical film of the present invention after the second layer is laminated.

{Characteristics of optical film}
(Optical film thickness)
The film thickness of the optical film of the present invention (total film thickness after laminating the first layer and the second layer on the base film) is preferably 5 to 100 μm, more preferably 10 to 80 μm, and particularly preferably 15 to 75 μm. .

[Layer structure of optical film]
The optical film of the present invention preferably has a first layer and a second layer in this order on one surface of the base film, is a polarizing plate protective film, and is a surface film of a liquid crystal display device. When the optical film of the present invention is a surface film, it is preferable that a hard coat layer is laminated. A preferred layer structure in this case is shown below.

Base film / first layer (adhesion layer) / second layer (low moisture permeability layer) / hard coat layer second layer (low moisture permeability layer) / first layer (adhesion layer) / base film / hard coat layer Base film / first layer (adhesion layer) / second layer (low moisture permeability layer) / hard coat layer / antireflection layer second layer (low moisture permeability layer) / first layer (adhesion layer) / base film / Hard coat layer / Antireflection layer Base film / first layer (adhesion layer) / second layer (low moisture permeability layer) / hard coat layer / antireflection layer / antifouling layer

[Hard coat layer]
It is also preferable to provide a hard coat layer as a functional layer in the optical film of the present invention.
In the present specification, the hard coat layer refers to a layer in which the pencil hardness of the transparent support is increased by forming the above layer. Practically, the pencil hardness (JIS K-5400) after laminating the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher.
The thickness of the hard coat layer is preferably 0.4 to 35 μm, more preferably 1 to 30 μm, and most preferably 1.5 to 20 μm.
In the present invention, the hard coat layer may be a single layer or a plurality of layers. When there are a plurality of hard coat layers, it is preferable that the total film thickness of all the hard coat layers is in the upper range.
The surface of the hard coat layer of the optical film of the present invention may be flat and uneven. Further, if necessary, the hard coat layer may contain translucent particles for imparting surface irregularities and internal scattering.

[Hard coat layer forming material]
In the present invention, the hard coat layer supports a composition containing a compound having an ethylenically unsaturated double bond, a polymerization initiator, and, if necessary, translucent particles, a fluorine-containing or silicone compound, and a solvent. It can be formed by coating, drying and curing directly on the body or via another layer. Each component will be described below.

[Compound having an ethylenically unsaturated double bond]
The composition for forming a hard coat layer that can be used in the present invention can contain a compound having an ethylenically unsaturated double bond. The compound having an ethylenically unsaturated double bond can function as a binder, and is preferably a polyfunctional monomer having two or more polymerizable unsaturated groups. The polyfunctional monomer having two or more polymerizable unsaturated groups can function as a curing agent, and the strength and scratch resistance of the coating film can be improved. The number of polymerizable unsaturated groups is more preferably 3 or more. These monomers can be used in combination of a monofunctional or bifunctional monomer and a trifunctional or higher monomer.

Examples of the compound having an ethylenically unsaturated double bond include a compound having a polymerizable functional group such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group and -C (O) OCH═CH ₂ is preferred. Particularly preferably, a compound containing three or more (meth) acryloyl groups in one molecule described below can be used.

  Specific examples of the compound having a polymerizable unsaturated bond include (meth) acrylic acid diesters of alkylene glycol, (meth) acrylic acid diesters of polyoxyalkylene glycol, and (meth) acrylic acid diesters of polyhydric alcohol. , (Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts, epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and the like.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. For example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO modified Tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate Rate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate, caprolactone-modified tris (acryloxyethyl) isocyanurate, etc. Can be mentioned.

  Commercially available polyfunctional acrylate compounds having a (meth) acryloyl group can be used, such as NK ester A-TMMT manufactured by Shin-Nakamura Chemical Co., Ltd., KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd. Can be mentioned. The polyfunctional monomer is described in paragraphs [0114] to [0122] of JP-A-2009-98658, and the same applies to the present invention.

  The compound having an ethylenically unsaturated double bond is a compound having a hydrogen-bonding substituent, adhesion to the support, low curl, fluorine-containing or silicone compound fixing point described later. To preferred. The hydrogen-bonding substituent refers to a substituent in which an atom having a large electronegativity such as nitrogen, oxygen, sulfur, or halogen and a hydrogen bond are covalently bonded. Specifically, OH—, SH—, — NH-, CHO-, CHN- and the like can be mentioned, and urethane (meth) acrylates and (meth) acrylates having a hydroxyl group are preferable. Commercially available polyfunctional acrylates having a (meth) acryloyl group can also be used. Shin Nakamura Chemical Co., Ltd. NK Oligo U4HA, NK Ester A-TMM-3, Nippon Kayaku Co., Ltd. KAYARAD PET-30 etc. can be mentioned.

  The content of the compound having an ethylenically unsaturated double bond in the composition for forming a hard coat layer provides a sufficient polymerization rate and imparts hardness and the like. 50 mass% or more is preferable with respect to the total solid content except, 60-99 mass% is more preferable, 70-99 mass% is still more preferable, 80-99 mass% is especially preferable.

As the composition for forming a hard coat layer, it is also preferable to use a compound having a cyclic aliphatic hydrocarbon and an ethylenically unsaturated double bond in the molecule. By using such a compound, low moisture permeability can be imparted to the hard coat layer. In order to improve the hard coat property, it is more preferable to use a compound having two or more cyclic aliphatic hydrocarbons and ethylenically unsaturated double bonds in the molecule.
When the composition for forming a hard coat layer contains a compound having a cycloaliphatic hydrocarbon and an ethylenically unsaturated double bond in the molecule, it has a cycloaliphatic hydrocarbon and an ethylenically unsaturated double bond in the molecule. 1-90 mass% is preferable in a compound which has an ethylenically unsaturated double bond in the composition for hard-coat layer formation, 2-80 mass% is more preferable, and 5-70 mass% is especially preferable.

When the composition for forming a hard coat layer contains a compound having a cyclic aliphatic hydrocarbon and an ethylenically unsaturated double bond in the molecule, it is preferable to further contain a (meth) acrylate having 5 or more functional groups.
When the composition for forming a hard coat layer further contains a (meth) acrylate having 5 or more functional groups, the (meth) acrylate having 5 or more functional groups has an ethylenically unsaturated double bond in the composition for forming a hard coat layer. In the compound which has, 1-70 mass% is preferable, 2-60 mass% is more preferable, and 5-50 mass% is especially preferable.

[Translucent particles]
In this invention, an uneven | corrugated shape can also be provided to the hard-coat layer surface by making a hard-coat layer contain translucent particle | grains, or an internal haze can also be provided.

  Translucent particles that can be used in the hard coat layer include polymethyl methacrylate particles (refractive index 1.49), crosslinked poly (acryl-styrene) copolymer particles (refractive index 1.54), melamine resin particles ( Refractive index 1.57), polycarbonate particles (refractive index 1.57), polystyrene particles (refractive index 1.60), cross-linked polystyrene particles (refractive index 1.61), polyvinyl chloride particles (refractive index 1.60), Examples include benzoguanamine-melamine formaldehyde particles (refractive index 1.68), silica particles (refractive index 1.46), alumina particles (refractive index 1.63), zirconia particles, titania particles, or particles having hollow or pores. It is done.

  Of these, crosslinked poly ((meth) acrylate) particles and crosslinked poly (acryl-styrene) particles are preferably used, and the refractive index of the binder is adjusted according to the refractive index of each light-transmitting particle selected from these particles. By adjusting, surface irregularities, surface haze, internal haze, and total haze suitable for the hard coat layer of the optical film of the present invention can be achieved.

The refractive index of the binder (translucent resin) is preferably 1.45 to 1.70, more preferably 1.48 to 1.65.
In addition, the difference in refractive index between the translucent particles and the binder of the hard coat layer (“refractive index of the translucent particles” − “refractive index of the hard coat layer excluding the translucent particles”) is an absolute value. As for it, Preferably it is less than 0.05, More preferably, it is 0.001-0.030, More preferably, it is 0.001-0.020. When the difference in refractive index between the light-transmitting particles and the binder in the hard coat layer is less than 0.05, the light refraction angle by the light-transmitting particles decreases, the scattered light does not spread to a wide angle, and the optical anisotropy There is no adverse effect such as depolarization of the transmitted light of the layer, which is preferable.

In order to realize the difference in refractive index between the particles and the binder, the refractive index of the light-transmitting particles may be adjusted, or the refractive index of the binder may be adjusted.
As a preferable first embodiment, a binder having a tri- or higher functional (meth) acrylate monomer as a main component (a refractive index after curing is 1.50 to 1.53) and an acrylic content of 50 to 100 mass percent is used. It is preferable to use a combination of translucent particles made of poly (meth) acrylate / styrene polymer. By adjusting the composition ratio of the acrylic component having a low refractive index and the styrene component having a high refractive index, it is easy to make the difference in refractive index between the translucent particles and the binder less than 0.05. The ratio of the acrylic component to the styrene component is preferably 50/50 to 100/0, more preferably 60/40 to 100/0, and most preferably 65/35 to 90/10 in terms of mass ratio. The refractive index of the light-transmitting particles comprising the crosslinked poly (meth) acrylate / styrene polymer is preferably 1.49 to 1.55, more preferably 1.50 to 1.54, and most preferably 1. 51 to 1.53.
As a preferred second embodiment, a binder composed of a monomer and inorganic fine particles is obtained by using inorganic fine particles having an average particle size of 1 to 100 nm in combination with a binder mainly composed of a tri- or higher functional (meth) acrylate monomer. The refractive index difference is adjusted to adjust the refractive index difference from the existing light-transmitting particles. The inorganic particles include oxides of at least one metal selected from silicon, zirconium, titanium, aluminum, indium, zinc, tin, and antimony. Specific examples include SiO ₂ , ZrO ₂ , TiO ₂ , and Al ₂ O. ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and the like. _Preferably, such _{SiO 2, ZrO 2, Al 2} O 3 and the like. These inorganic particles can be used by mixing in the range of 1 to 90% by mass with respect to the total amount of monomers, and preferably 5 to 65% by mass.
Here, the refractive index of the hard coat layer excluding the translucent particles can be quantitatively evaluated by directly measuring with an Abbe refractometer or by measuring a spectral reflection spectrum or a spectral ellipsometry. The refractive index of the translucent particles is measured by measuring the turbidity by dispersing an equal amount of the translucent particles in the solvent in which the refractive index is changed by changing the mixing ratio of two kinds of solvents having different refractive indexes. It is measured by measuring the refractive index of the solvent when the turbidity is minimized with an Abbe refractometer.

  The average particle diameter of the translucent particles is preferably 1.0 to 12 μm, more preferably 3.0 to 12 μm, still more preferably 4.0 to 10.0 μm, and most preferably 4.5 to 8 μm. By setting the refractive index difference and the particle size within the above ranges, the light scattering angle distribution does not spread to a wide angle, and it is difficult to cause blurring of characters on the display and a decrease in contrast. It is not necessary to increase the thickness of the layer to be added, and 12 μm or less is preferable because it is difficult to cause problems such as curling and cost increase. Furthermore, it is preferable that the amount falls within the above range from the viewpoint that the coating amount during coating can be suppressed, drying is quick, and surface defects such as drying unevenness are unlikely to occur.

  The measuring method of the average particle diameter of the translucent particles can be any measuring method as long as it is a measuring method for measuring the average particle diameter of the particles, but preferably a transmission electron microscope (magnification of 500,000 to 2,000,000 times) The particles are observed by observing 100 particles, and the average value can be obtained as the average particle diameter.

  The shape of the translucent particles is not particularly limited, but in addition to the spherical particles, translucent particles having different shapes such as irregularly shaped particles (for example, non-spherical particles) may be used in combination. In particular, when the minor axes of non-spherical particles are aligned in the normal direction of the hard coat layer, particles having a smaller particle diameter than the true spherical particles can be used.

  The translucent particles are preferably blended so as to be contained in an amount of 0.1 to 40% by mass in the total solid content of the hard coat layer. More preferably, it is 1-30 mass%, More preferably, it is 1-20 mass%. The internal haze can be controlled within a preferable range by adjusting the blending ratio of the translucent particles within the above range.

Moreover, the application amount of translucent particles is preferably 10 to 2500 mg / m ² , more preferably 30 to 2000 mg / m ² , and still more preferably 100 to 1500 mg / m ² .

<Translucent particle preparation, classification method>
Examples of the method for producing the translucent particles include a suspension polymerization method, an emulsion polymerization method, a soap-free emulsion polymerization method, a dispersion polymerization method, a seed polymerization method, and the like, and any method may be used. These production methods are described in, for example, “Experimental Methods for Polymer Synthesis” (Takayuki Otsu and Masaaki Kinoshita, Chemical Dojinsha), pages 130 and 146 to 147, “Synthetic Polymers”, Vol. 246-290, 3rd volume, p. 1 to 108, etc., and Japanese Patent Nos. 2543503, 3508304, 2746275, 3521560, 3580320, and Japanese Patent Laid-Open No. 10-1561. Reference can be made to methods described in JP-A No. 7-2908, JP-A No. 5-297506, JP-A No. 2002-145919, and the like.

The particle size distribution of the translucent particles is preferably monodisperse particles in terms of haze value and diffusibility control, and uniformity of the coated surface. The CV value representing the uniformity of the particle diameter is preferably 15% or less, more preferably 13% or less, and still more preferably 10% or less. Further, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less of the total number of particles, more preferably 0.1% or less. Yes, more preferably 0.01% or less. Particles having such a particle size distribution are also effective means of classification after preparation or synthesis reaction, and particles having a desired distribution can be obtained by increasing the number of classifications or increasing the degree of classification. .
It is preferable to use a method such as an air classification method, a centrifugal classification method, a sedimentation classification method, a filtration classification method, or an electrostatic classification method for classification.

[Thickener]
A thickener can be used to adjust the viscosity of the coating solution.
The term “thickener” as used herein means one that increases the viscosity of the liquid by adding it.

Examples of such thickeners include, but are not limited to:
Poly-ε-caprolactone poly-ε-caprolactone diol poly-ε-caprolactone triol polyvinyl acetate poly (ethylene adipate)
Poly (1,4-butylene adipate)
Poly (1,4-butylene glutarate)
Poly (1,4-butylene succinate)
Poly (1,4-butylene terephthalate)
polyethylene terephthalate)
Poly (2-methyl-1,3-propylene adipate)
Poly (2-methyl-1,3-propylene glutarate)
Poly (neopentyl glycol adipate)
Poly (neopentyl glycol sebacate)
Poly (1,3-propylene adipate)
Poly (1,3-propylene glutarate)
Polyvinyl butyral polyvinyl formal polyvinyl acetal polyvinyl propanal polyvinyl hexanal polyvinyl pyrrolidone polyacrylic ester polymethacrylic acid ester cellulose acetate cellulose propionate cellulose acetate butyrate

  In addition, known viscosities such as layered compounds such as smectite, mica, bentonite, silica and montmorillonite described in JP-A-8-325491, and sodium polyacrylate, JP-A-10-219136 ethylcellulose, polyacrylic acid, organic clay, etc. A regulator or a thixotropic agent can be used. As the thixotropic agent, those obtained by organically treating a layered compound having a particle size of 0.3 μm or less are particularly preferable. A particle size of 0.1 μm or less is more preferable. The particle size of the layered compound can be considered as the length of the long axis. Usually, it is suitable to set it as about 1-10 mass parts with respect to 100 mass parts of ultraviolet curable resin.

[Photopolymerization initiator]
The hard coat layer forming composition preferably contains a photopolymerization initiator. The photopolymerization initiator described in the second layer can also be preferably used in the composition for forming a hard coat layer.

  The content of the photopolymerization initiator in the composition for forming the hard coat layer is sufficiently high to polymerize the polymerizable compound contained in the composition for forming the hard coat layer and is small enough not to increase the starting point excessively. From the reason that the amount is set, the amount is preferably 0.5 to 8% by mass, and more preferably 1 to 5% by mass with respect to the total solid content in the composition for forming a hard coat layer.

[Ultraviolet absorber]
The optical film of the present invention is used for a polarizing plate or a liquid crystal display device member, but from the viewpoint of preventing deterioration of the polarizing plate, liquid crystal, or the like, the hard coat layer contains an ultraviolet absorber in a range that does not inhibit UV curing. Thus, ultraviolet absorption can be imparted to the optical film.

[solvent]
When laminating a hard coat layer on the optical film of the present invention, the composition for forming the hard coat layer may contain a solvent. Various solvents can be used as the solvent in consideration of the solubility of the monomer, the dispersibility of the light-transmitting particles, the drying property at the time of coating, and the like. Examples of such organic solvents include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate, carbonic acid. Methyl ethyl, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, Methyl propionate, ethyl propionate, γ-ptyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-metho Siethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, methyl acetoacetate and other methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexyl Alcohol, isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, ethylene glycol ethyl ether, ethylene glycol isopropyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, ethyl carbitol, butyl carbitol , Hexane, heptane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, tolu Examples thereof include ene and xylene, and these can be used alone or in combination of two or more.

  It is preferable to use a solvent so that the solid content of the composition for forming a hard coat layer is in the range of 20 to 80% by mass, more preferably 30 to 75% by mass, and still more preferably 40 to 70% by mass. It is.

[Antireflection layer]
Lamination of the antireflection layer on the hard coat layer as described above is one of the preferred embodiments of the present invention. In the present invention, a known antireflection layer can be preferably used. Among them, a UV curable antireflection layer is preferable.
The antireflection layer may be either a low-reflectance layer having a single-layer thickness λ / 4 or a multilayer structure, but a low-reflectance layer having a single-layer thickness λ / 4 is particularly preferable. The low refractive material that can be preferably used in the present invention will be described below, but the present invention is not limited thereto.

[Material for low refractive index layer]
The material of the low refractive index layer contained in the antireflection layer will be described below.

[Inorganic fine particles]
From the viewpoint of lowering the refractive index and improving scratch resistance, it is preferable to use inorganic fine particles in the low refractive index layer. The inorganic fine particles are not particularly limited as long as the average particle size is 5 to 120 nm, but inorganic low refractive index particles are preferable from the viewpoint of lowering the refractive index.

  Examples of the inorganic fine particles include magnesium fluoride and silica fine particles because of their low refractive index. In particular, silica fine particles are preferable in terms of refractive index, dispersion stability, and cost. The size (primary particle size) of these inorganic particles is preferably 5 to 120 nm, more preferably 10 to 100 nm, 20 to 100 nm, and most preferably 30 to 90 nm.

  If the particle size of the inorganic fine particles is too small, the effect of improving the scratch resistance is reduced. If the particle size is too large, fine irregularities are formed on the surface of the low refractive index layer, and the appearance such as black tightening and the integrated reflectance are deteriorated. Further, when hollow silica fine particles described later are used, if the particle size is too small, the ratio of the cavity portion is reduced and a sufficient decrease in the refractive index cannot be expected. The inorganic fine particles may be either crystalline or amorphous, and may be monodispersed particles or aggregated particles as long as a predetermined particle size is satisfied. The shape is most preferably a spherical diameter, but may be indefinite.

The coating amount of the inorganic fine particles is ^{preferably 1mg / m 2 ~100mg / m 2} , more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably from ^{10mg / m 2 ~60mg / m 2} . If the amount is too small, a sufficiently low refractive index cannot be expected or the effect of improving the scratch resistance is reduced. If the amount is too large, fine irregularities are formed on the surface of the low refractive index layer, and the appearance and integration such as black tightening Reflectivity deteriorates.

(Porous or hollow fine particles)
In order to reduce the refractive index, it is preferable to use fine particles having a porous or hollow structure. It is particularly preferable to use hollow structure silica particles. The porosity of these particles is preferably 10 to 80%, more preferably 20 to 60%, and most preferably 30 to 60%. It is preferable that the void ratio of the hollow fine particles be in the above range from the viewpoint of lowering the refractive index and maintaining the durability of the particles.

  When the porous or hollow particles are silica, the refractive index of the fine particles is preferably 1.10 to 1.40, more preferably 1.15 to 1.35, and most preferably 1.15 to 1.30. is there. The refractive index here represents the refractive index of the entire particle, and does not represent the refractive index of only the outer shell silica forming the silica particles.

  Further, two or more kinds of hollow silica having different particle average particle sizes can be used in combination. Here, the average particle diameter of the hollow silica can be determined from an electron micrograph.

The specific surface area of the hollow silica in the present invention is preferably from 20 to 300 m ² / g, more preferably 30~120m ² / g, most preferably 40~90m ² / g. The surface area can be determined by the BET method using nitrogen.

  In the present invention, silica particles having no voids can be used in combination with hollow silica. The preferred particle size of silica without voids is 30 nm to 150 nm, more preferably 35 nm to 100 nm, and most preferably 40 nm to 80 nm.

[Inorganic fine particle surface treatment method]
Further, in the present invention, inorganic fine particles can be used after being surface-treated with a silane coupling agent or the like by a conventional method.
In particular, in order to improve dispersibility in the binder for forming a low refractive index layer, the surface of the inorganic fine particles is preferably treated with a hydrolyzate of an organosilane compound and / or a partial condensate thereof. In this case, it is more preferable to use either an acid catalyst or a metal chelate compound or both. The method for treating the surface of the inorganic fine particles is described in paragraphs [0046] to [0076] of JP-A-2008-242314. The organosilane compound, the siloxane compound, and the solvent for the surface treatment described in the above document In addition, a surface treatment catalyst, a metal chelate compound, and the like can be suitably used in the present invention.

For the low refractive index layer, (b2) a fluorine-containing or non-fluorine-containing monomer having a polymerizable unsaturated group can be used. As for the non-fluorinated monomer, it is also preferable to use a compound having an ethylenically unsaturated double bond described as being usable in the hard coat layer. As the fluorine-containing monomer, a fluorine-containing polyfunctional monomer (d) represented by the following general formula (1), containing 35% by mass or more of fluorine and having a calculated value of all cross-linking molecular weights smaller than 500 is used. Is preferred.
General formula (1): Rf ₂ {-(L) _m -Y} _n
(In General Formula (1), Rf ₂ represents an n-valent group containing at least a carbon atom and a fluorine atom, n represents an integer of 3 or more, L represents a single bond or a divalent linking group, and m represents Represents 0 or 1. Y represents a polymerizable unsaturated group.)
Rf ₂ may contain at least one of an oxygen atom and a hydrogen atom. Further, Rf ₂ is a chain (straight or branched) or cyclic.

Y is preferably a group containing two carbon atoms forming an unsaturated bond, more preferably a radical polymerizable group, a (meth) acryloyl group, an allyl group, an α-fluoroacryloyl group, and Those selected from —C (O) OCH═CH ₂ are particularly preferred. Among these, from the viewpoint of polymerizability, (meth) acryloyl group, allyl group, α-fluoroacryloyl group, and C (O) OCH═CH ₂ having radical polymerizability are more preferable.

L represents a divalent linking group, specifically, an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, -O-, -S-, -N (R)-, 1 to carbon atoms. A group obtained by combining 10 alkylene group and —O—, —S— or N (R) —, a combination of an arylene group having 6 to 10 carbon atoms and —O—, —S— or N (R) —. Represents the resulting group. R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. When L represents an alkylene group or an arylene group, the alkylene group and the arylene group represented by L are preferably substituted with a halogen atom, and preferably substituted with a fluorine atom.
Specific examples of the compound represented by the general formula (1) are described in paragraphs [0121] to [0163] of JP2010-15211A.

[Optically anisotropic layer]
An optically anisotropic layer can also be provided on the optical film of the present invention. The optically anisotropic layer may be an optically anisotropic layer in which a film having a constant retardation is uniformly formed in the plane, and the direction of the slow axis and the magnitude of the retardation are different from each other. It may be an optically anisotropic layer having a pattern in which retardation regions are regularly arranged in a plane.
As described above, the optical film of the present invention is preferably a surface film on which a hard coat layer of a liquid crystal display device is laminated. When the optical film of the present invention has both a hard coat layer and an optically anisotropic layer, the optically anisotropic layer is preferably formed on a surface on which the hard coat layer is not laminated via a base film. .

When the optical film of the present invention has such an aspect, the first layer and the second layer may be laminated on the same side as the hard coat layer with respect to the base film, or opposite to the hard coat layer. It may be provided on the side or may be laminated on both sides of the base film.
As the preferred layer configuration when the first layer and the second layer are laminated on the same side as the hard coat layer with respect to the base film, the preferred layer configuration when laminating the above hard coat layer can be used. .
On the other hand, when the first layer and the second layer are laminated on the same side as the hard coat layer and the optically anisotropic layer with respect to the base film, the first layer and the second layer are optically anisotropic with the base film. May be laminated between the conductive layers, or may be laminated in the order of the base film, the optically anisotropic layer, the first layer, and the second layer.

  The optically anisotropic layer can be selected from materials and production conditions according to various uses, but in the present invention, an optically anisotropic layer using a polymerizable liquid crystalline compound is preferable. In that case, it is also a preferred embodiment that an alignment film is formed between the optically anisotropic layer and the substrate film in contact with the optically anisotropic layer.

  A preferred example having an optically anisotropic layer formed uniformly in the plane is an embodiment in which the optically anisotropic layer is a λ / 4 film, and is particularly useful as a member of an active 3D liquid crystal display device. As an aspect in which an optically anisotropic layer and a hard coat layer of a λ / 4 film are laminated on opposite surfaces through a base film, they are described in JP2012-098772A and JP20121277982A. Such an embodiment can be preferably used in the optical film of the present invention.

On the other hand, as a preferable example of the optically anisotropic layer in which a pattern is formed, a pattern type λ / 4 film can be mentioned. It can be preferably used.
Moreover, the aspect which combined the photo-alignment film and pattern exposure described in the Japanese translations of PCT publication No. 2012-517024 gazette (WO2010 / 090429 gazette) can also be preferably used with the optical film of this invention.

[Layer structure of optical film having optically anisotropic layer]
A preferred layer structure when the optical film of the present invention has an optically anisotropic layer is shown below.

Optically anisotropic layer / base film / first layer (adhesion layer) / second layer (low moisture permeable layer) / hard coat layer optically anisotropic layer / second layer (low moisture permeable layer) / first layer (Adhesion layer) / Base film / Hard coat layer Optical anisotropic layer / Base film / First layer (Adhesion layer) / Second layer (low moisture permeability layer) / Hard coat layer / Antireflection layer Optical anisotropic Layer / second layer (low moisture permeability layer) / first layer (adhesion layer) / base film / hard coat layer / antireflection layer

  In the case of having an optically anisotropic layer, the optical anisotropy is preferably formed from a liquid crystal compound having a curable group such as an unsaturated polymerizable group, and an alignment film is formed under the liquid crystal layer. preferable. In the present invention, the alignment film is also preferably formed from a curable composition containing a radical polymerizable compound, and in that case, the following layer structure is particularly preferable.

Optically anisotropic layer / second layer (low moisture permeability layer) / first layer (adhesion layer) / base film / hard coat layer optically anisotropic layer / second layer (low moisture permeability layer) / first layer (Adhesion layer) / Base film / Hard coat layer / Antireflection layer

[Method for producing optical film]
The method for producing an optical film of the present invention is a method for producing an optical film having a base film, a first layer, and a second layer in this order, and an ethylenically unsaturated double bond is formed on the base film. A step of applying a curable composition for forming a first layer containing a compound having a viscosity and curing to form a first layer having an elastic modulus of 1.0 to 5.0 GPa, and a cyclic aliphatic hydrocarbon group And applying a curable composition for forming a second layer containing at least one of a compound having an ethylenically unsaturated double bond and a compound having a fluorene ring and an ethylenically unsaturated double bond. And a step of forming the second layer.

  As a coating method of the curable composition for forming the first layer and the curable composition for forming the second layer, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, and a gravure coating method And die coating method. A micro gravure coating method, a wire bar coating method, and a die coating method (see US Pat. No. 2,681,294 and JP-A-2006-122889) are more preferable, and a die coating method is particularly preferable.

  The curable composition for forming the first layer and the curable composition for forming the second layer are preferably heated and dried in a drying zone in order to dry the solvent after being applied. In this case, the temperature of the drying zone is preferably 25 ° C. to 140 ° C., the first half of the drying zone is relatively low temperature, and the second half is preferably relatively high temperature. However, it is preferably below the temperature at which components other than the solvent contained in the coating composition of each layer start to volatilize.

After the solvent drying zone, it is preferable to pass the zone through which the layers are cured by ionizing radiation irradiation on the web to cure the coating film. For example, if the coating film is ultraviolet-curable, preferably to cure the coating by an irradiation amount of 10mJ ^/ cm ² ~1000mJ ^/ cm 2 by an ultraviolet lamp. At that time, the irradiation distribution in the width direction of the web is preferably 50 to 100%, more preferably 80 to 100%, including both ends with respect to the central maximum irradiation. Further, when it is necessary to purge nitrogen gas or the like to lower the oxygen concentration in order to promote surface hardening, the oxygen concentration is preferably 0.01% to 5%, and the distribution in the width direction is 2% or less in terms of oxygen concentration. Is preferred. In the case of ultraviolet irradiation, ultraviolet rays emitted from light such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used. Moreover, in order to accelerate | stimulate hardening reaction, temperature can also be raised at the time of hardening, 25-100 degreeC is preferable, More preferably, it is 30-80 degreeC, Most preferably, it is 40-70 degreeC.

[Polarizer]
The polarizing plate of the present invention includes a polarizer and at least one optical film of the present invention as a protective film for the polarizer.
The optical film of the present invention can be used as a protective film for a polarizing plate. When using as a protective film for polarizing plates, the production method of a polarizing plate is not specifically limited, It can produce by a general method. There is a method in which the obtained optical film is treated with an alkali and bonded to both sides of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Moreover, you may perform the above surface treatments. The bonding surface of the optical film with the polarizer may be a surface on which the second layer is laminated, or a surface on which the second layer is not laminated.
Examples of the adhesive used to bond the protective film treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like.
The polarizing plate is composed of a polarizer and a protective film for protecting both surfaces of the polarizer, and further composed of a protective film bonded to one surface of the polarizing plate and a separate film bonded to the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the adhesive layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

[Liquid Crystal Display]
The liquid crystal display device of the present invention includes a liquid crystal cell and the polarizing plate of the present invention disposed in at least one of the liquid crystal cells, so that the optical film of the present invention contained in the polarizing plate is the outermost layer. It is arranged.

(General liquid crystal display device configuration)
The liquid crystal display device includes a liquid crystal cell having a liquid crystal supported between two electrode substrates, two polarizing plates disposed on both sides thereof, and, if necessary, between the liquid crystal cell and the polarizing plate. At least one optical compensation film is arranged.
The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The liquid crystal cell may further be provided with a gas barrier layer, a hard coat layer, or an undercoat layer (undercoat layer) (used for adhesion of the transparent electrode layer). These layers are usually provided on the substrate. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

In a liquid crystal display device, a substrate including a liquid crystal cell is usually disposed between two polarizing plates. The protective film for polarizing plates to which the optical film of the present invention is applied is a protective film for any of the two polarizing plates. Although it can be used, it is preferable to use as a protective film arrange | positioned outside a liquid crystal cell with respect to a polarizer among two protective films of each polarizing plate.
Of the two polarizing plates, it is particularly preferable to dispose the optical film of the present invention as a viewing-side protective film of the viewing-side polarizing plate.
Moreover, after arranging the optical film of the present invention as the protective film on the viewing side of the viewing side polarizing plate of the two polarizing plates, the present invention is also applied to the backlight side protective film of the backlight side polarizing plate. It is also a preferable aspect to dispose an optical film, suppress expansion and contraction of the polarizer contained in the two polarizing plates, and prevent warping of the panel.

(Types of liquid crystal display devices)
The film of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroly Liquid Liquid Crystal), OCB (Optically QuantNW). Various display modes such as ECB (Electrically Controlled Birefringence) and HAN (Hybrid Aligned Nematic) have been proposed. In addition, a display mode in which the above display mode is oriented and divided has been proposed. The optical film of the present invention is effective in any display mode liquid crystal display device. Further, it is effective in any of a transmissive type, a reflective type, and a transflective liquid crystal display device.

  Hereinafter, the present invention will be specifically described based on examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the present invention is not limited to the following examples.

[Example 1]
[Preparation of curable composition for forming first layer]
A curable composition for forming a first layer was prepared with the composition shown below.
MEK 16.90 parts by mass MIBK 59.16 parts by mass Methyl acetate 8.45 parts by mass A-TMMT (NK ester manufactured by Shin-Nakamura Chemical Co., Ltd.) 14.24 parts by mass Byron UR-1510 (polyester urethane [Toyobo ( Product)])
0.77 parts by mass Irg127 (Irquagua 127) [manufactured by BASF] 0.46 parts by mass

[Preparation of curable composition for forming second layer]
A curable composition for forming the second layer was prepared with the composition shown below.
MEK 13.50 parts by mass MIBK 37.50 parts by mass A-DCP: tricyclodecane dimethanol diacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.]
53.35 parts by mass Irg907 (Ilquagua 907) [manufactured by BASF Corp.] 1.65 parts by mass

[Production of optical film]
A die coating method using a slot die described in Example 1 of Japanese Patent Application Laid-Open No. 2006-122889 by unwinding Fujitac TD60 (manufactured by Fuji Film Co., Ltd., width 1,340 mm, thickness 60 μm) as a base film. Then, the curable composition for forming the first layer was applied under the condition of a conveyance speed of 30 m / min, and dried at 60 ° C. for 150 seconds. Thereafter, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) having an oxygen concentration of about 1.0% by volume under nitrogen purge and an output of 160 W / cm, an ultraviolet ray having an illuminance of 400 mW / cm ² and an irradiation amount of 70 mJ / cm ² . Was applied to cure the coating layer and wound up. The coating amount was adjusted so that the film thickness of the first layer was 0.3 μm. About the obtained 1st layer, the nanoindentation elastic modulus (Er) was measured. The nanoindentation elastic modulus (Er) was measured using an ultra-micro hardness test system picodenter manufactured by Fischer. For the measurement, a triangular pyramid type diamond indenter called a Belkovic indenter (tip ridge angle 142.3 °) was used as an indenter. A triangular pyramid-shaped diamond indenter was applied to the sample surface at a right angle, a load was gradually applied, and the load was gradually returned to 0 after reaching the maximum load. A value P / A obtained by dividing the maximum load P at this time by the projected area A of the indenter contact portion was calculated as nanoindentation hardness (H). The nanoindentation elastic modulus (Er) was calculated using the following formula, assuming the slope S of the unloading curve.
Er = (S × √π) / (2√A) (π is the circumference)
Details of the principle are described in Handbook of Micro / NanoTribology (CRC edited by BharatBhushan).
Next, the second layer-forming curability is formed on the first layer by the die coating method using the slot die described in Example 1 of Japanese Patent Application Laid-Open No. 2006-122889 on the condition of a conveyance speed of 30 m / min. The composition was applied and dried at 60 ° C. for 150 seconds. Thereafter, an ultraviolet ray having an illuminance of 400 mW / cm ² and an irradiation amount of 280 mJ / cm ² using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 1.0% by volume under a nitrogen purge and an output of 160 W / cm. Was applied to cure the coating layer and wound up. The coating amount was adjusted so that the thickness of the second layer was 10 μm.
The obtained optical film was taken as Example 1.

<Preparation of Examples 2-27 and Comparative Examples 1-7>
In the production of Example 1 above, except that the composition of the curable composition for forming the first layer and the curable composition for forming the second layer was as described in Table 1 below, Optical films of Examples 2 to 27 and Comparative Examples 6 to 7 were produced. Moreover, the 1st layer was not formed but the composition of the curable composition for 2nd layer formation was made into the composition of the following Table 1, and the optical film of Comparative Examples 1-5 was produced. In addition, in the curable composition for forming the second layer of Example 9 and Comparative Example 3, rosin (KR-614 [manufactured by Arakawa Chemical Co., Ltd.]) was added.

The materials used are shown below.
-A-TMMT: NK ester [manufactured by Shin-Nakamura Chemical Co., Ltd.]
(Molecular weight: 352, acrylic equivalent: 88)
ATM-4E: NK ester [made by Shin-Nakamura Chemical Co., Ltd.]
(Molecular weight: 529, acrylic equivalent: 132)
-A-200: NK ester [made by Shin-Nakamura Chemical Co., Ltd.]
(Molecular weight: 308, acrylic equivalent: 154)
UV-1700B: urethane acrylate [manufactured by Nippon Synthetic Chemical Co., Ltd.]
(Molecular weight: 2000, acrylic equivalent: 200)
・ Byron UR-1510: Polyester urethane [manufactured by Toyobo Co., Ltd.]
Kane Ace M210: MMA-BA core shell [manufactured by Kaneka Corporation]
-Clarity LA2140E: MMA-BA block [manufactured by Kuraray Co., Ltd.]
Irg127 (Irquagua 127): polymerization initiator [manufactured by BASF]
A-DCP: Tricyclodecane dimethanol diacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.]
DCP: tricyclodecane dimethanol dimethacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.]
AD-DA: 1,3-adamantanediol diacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.]
・ Irg907 (Irquagua 907): Polymerization initiator [manufactured by BASF]
KR-614: Pine Crystal [Arakawa Chemical Industries, Ltd.]

[Evaluation of optical film]
About the produced optical film of each Example and a comparative example, the following physical-property measurement and evaluation were performed. The results are shown in Table 1 below.

(A) Moisture permeability of optical film and second layer (moisture permeability at 40 ° C. and 90% relative humidity)
The 70 mmφ optical film samples of each Example and Comparative Example were each conditioned at 40 ° C. and 90% relative humidity for 24 hours, and the moisture permeability of the optical film was measured by the method described in JIS Z-0208.
Further, the moisture permeability of the base film and the first layer of each optical film of each example and comparative example is measured, and from the moisture permeability of the base film and the first layer and the moisture permeability of the optical film, in the specification The moisture permeability of the second layer was calculated using the formula (1) described above.

(B) Adhesion evaluation On the surface having the second layer of the optical film, 11 vertical and 11 horizontal cuts were made with a cutter knife in a grid pattern to make a total of 100 squares of 1 cm × 1 cm in size. The polyester film adhesive tape “NO.31B” manufactured by Nitto Denko Co., Ltd. was pressed, left for 1 minute, and then peeled off vigorously to conduct an adhesion test between the base film and the coating layer.
The presence or absence of peeling after the above adhesion test was visually observed, and a case where an area of 1/4 or more in the ridge was peeled was regarded as a peeling ridge, the number of peeling ridges was counted, and the following two-stage evaluation was performed. It was.
A: The peeling wrinkle was 0 to 10 mm B: The peeling wrinkle was 11 to 100 mm

(C) Evaluation of floating The evaluation method of floating will be described below with reference to FIGS.
As shown in FIG. 1, the optical film 1 was punched into a 60 mm × 60 mm square using a Thomson blade (MIR-CI23: manufactured by Nakayama Co., Ltd.) to prepare an evaluation sample 2. In the punching method, the blade was brought into contact with the side on which the second layer was formed, and punched vertically toward the direction of the base film.
Thereafter, as indicated by a broken line in FIG. 2, 5 mm inside the punched line of the evaluation sample 2 punched out was cut out as a section 3, and the cross section was observed with a 1000 × optical microscope from the direction of the arrow in FIG.
As shown in FIG. 3, in the cross section where the floating occurs, the second layer A is lifted from the first layer B formed on the base film at the end of the section 3 cut out from the evaluation sample 2. A void is generated.
In the present example, the cross section of the arbitrary 30 positions on the four sides of the evaluation sample 2 is observed by the above method, and the first layer B and the second layer 2 are formed from the end of the section 3 cut out from the evaluation sample 2. The case where a void portion was recognized with a width of 5 μm or more along the interface with the layer A was considered as floating, and the following four stages of evaluation were performed by counting the cross-sectional portions that were recognized as floating.
A: The float was 0 place B: The float was 1 place C: The float was 2-3 places D: The float was 4 places or more

  [Wt%] in the said table | surface represents the mass% with respect to the total solid of a composition.

  As shown in Table 1, since Examples 1-27 formed the 2nd layer which consists of a specific composition, the moisture permeability of an optical film and the evaluation result of adhesiveness were excellent. Moreover, since the 1st layer which consists of a specific composition is formed and the elasticity modulus of the 1st layer is controlled, compared with Comparative Examples 2-7, the evaluation result of a float becomes a favorable thing. It was.

1; Optical film 2; Sample 3 for evaluation; Section A; Second layer B; First layer

Claims (13)

An optical film having a base film, a first layer, and a second layer in this order,
The first layer is a layer formed by curing a curable composition for forming a first layer containing a compound having an ethylenically unsaturated double bond and having an elastic modulus of 1.0 to 5.0 GPa. ,
The second layer contains at least one of a compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond, and a compound having a fluorene ring and an ethylenically unsaturated double bond. An optical film, which is a layer formed by curing a curable composition for formation.   The first layer forming curable composition comprises 30 to 99 compounds having the ethylenically unsaturated double bond, when the total solid content of the first layer forming curable composition is 100% by mass. The optical film according to claim 1, which is contained by mass%.   The curable composition for forming the second layer has the cyclic aliphatic hydrocarbon group and the ethylenically unsaturated double bond when the total solid content of the curable composition for forming the second layer is 100% by mass. The optical film of Claim 1 or 2 which contains 50-99 mass% of at least any one of the compound which has these, and the compound which has a fluorene ring and an ethylenically unsaturated double bond.   The optical film according to claim 1, wherein the curable composition for forming a first layer further contains an elastomer.   The optical film according to claim 4, wherein the elastomer is a polyurethane-based, acrylic-based, or polystyrene-based elastomer.   The optical film according to any one of claims 1 to 5, wherein the compound having an ethylenically unsaturated double bond contained in the curable composition for forming a first layer has a molecular weight of 2000 or less.   The optical film according to any one of claims 1 to 6, wherein the compound having an ethylenically unsaturated double bond contained in the curable composition for forming a first layer has an acrylic equivalent of 200 or less. .   The optical film according to claim 1, wherein the first layer has a thickness of less than 1.0 μm. The curable composition for forming the second layer contains a compound having a cyclic aliphatic hydrocarbon group and an ethylenically unsaturated double bond, and the cyclic aliphatic hydrocarbon group is represented by the following general formula (I) and It is group represented by at least 1 sort (s) of Formula (IV), The optical film of any one of Claims 1-8.

In general formula (I), L and L1 each independently represent a divalent or higher valent linking group, and n represents an integer of 1 to 3.

In general formula (IV), L and L1 each independently represent a single bond or a divalent or higher linking group, and L2 represents a hydrogen atom, a single bond or a divalent or higher valent linking group.   The optical film according to claim 1, wherein the curable composition for forming a second layer further contains a rosin compound.   The polarizing plate which contains at least 1 sheet of polarizer and the optical film of any one of Claims 1-10 as a protective film of the said polarizer.   A liquid crystal display device comprising: a liquid crystal cell; and the polarizing plate according to claim 11 disposed on at least one surface of the liquid crystal cell, wherein the optical film is an outermost layer. A method for producing an optical film having a base film, a first layer, and a second layer in this order,
On the base film,
Applying a curable composition for forming a first layer containing a compound having an ethylenically unsaturated double bond and curing to form a first layer having an elastic modulus of 1.0 to 5.0 GPa; ,
Curable composition for second layer formation containing at least one of a compound having a cycloaliphatic hydrocarbon group and an ethylenically unsaturated double bond and a compound having a fluorene ring and an ethylenically unsaturated double bond Applying and curing to form a second layer. An optical film manufacturing method comprising:

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