WO2019098159A1 - Method for manufacturing polarizing plate, method for manufacturing liquid crystal display device, and optical film - Google Patents

Abstract

The present invention provides: a method for manufacturing a polarizing plate, the method having a step for forming a coating layer on a temporary support body and drying the coating layer to thereby produce a transfer film in which an optical film is formed on the temporary support body, a step for affixing a polarizer to an optical-film-side surface of the transfer film, and a step for peeling the temporary support body away from the transfer film, wherein the optical film includes 25-45 mass% of a copolymer including structural units derived from butadiene with respect to the total solids content of the optical film, the optical film includes 0.1-10 mass% of a polyester-based additive with respect to the total solids content of the optical film, the thickness of the optical film is 4-10 μm, the rupture elongation of the optical film is 2.5% or higher in an environment at 25°C in a sample having a thickness of 30 μm and a width of 10 mm, and the arithmetic mean roughness of a surface of the temporary support body on a side on which the optical film is formed is 40 nm or less; a method for manufacturing a liquid crystal display device using a polarizing plate manufactured using the manufacturing method described above; and the optical film described above.

Description

Method of manufacturing polarizing plate, method of manufacturing liquid crystal display device, and optical film

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

Optical films are used for various applications, for example, for polarizing plates.
A polarizing plate is used as a member such as a liquid crystal display (LCD) or an organic electroluminescence (organic EL) display (OLED), and plays an important role in the display performance. A general polarizing plate has a configuration in which an optical film is bonded to one side or both sides of a polarizer in which a dichroic dye such as iodine complex is adsorbed and oriented to a polyvinyl alcohol (PVA) resin.
In recent years, display devices have been increased in size, thickness, and flexibility, and accordingly, polarizing plates have been required to have different functions and thicknesses.

In order to reduce the thickness of the polarizing plate, it is necessary to reduce the thickness of the optical film constituting the polarizing plate. For example, in Patent Document 1, a coating film is provided on a temporary support, and a polarizer is attached to the coating film, and then the coating film having a thickness of less than 10 μm is attached by peeling the temporary support from the coating film. A method of making combined polarizers is described.

International Publication No. 2014/199934

Patent Document 1 describes a coated film mainly composed of a cycloolefin polymer, and according to the study of the present inventors, a coated film having excellent releasability from a temporary support and having low birefringence is disclosed. On the other hand, after being made into a polarizing plate form and then assembled into a large display device and placed under high temperature and high humidity, the coating film can not follow the elongation due to the moisture absorption of the PVA-based resin forming the polarizer. , It was found that there is an event that the polarizing plate breaks down.
In general, the characteristic function of the film largely depends on the main material of the film, but the main material is not necessarily able to cope with the deformation of the PVA-based resin under high temperature and high humidity, and is rather disadvantageous in many cases. In addition, it is also desirable that unevenness in luminance be suppressed when an optical film or a polarizing plate including the same is applied to an image display device.

In view of the above problems, the problem to be solved by the present invention is a method of manufacturing a polarizing plate capable of suppressing breakage failure under high temperature and high humidity and suppressing unevenness in luminance when applied to an image display device. It is an object of the present invention to provide a method of manufacturing a liquid crystal display device, and an optical film capable of suppressing a breakdown failure of a polarizing plate under high temperature and high humidity and suppressing unevenness in luminance when applied to an image display device.

The present inventors have found that the above-mentioned problems can be solved by the following action of the optical film (functional film) according to the present invention.
That is, the optical film of the present invention contains a component having extensibility, and when the optical film of the present invention is used for a polarizing plate, the optical film of the present invention follows the elongation of the polarizer under high temperature and high humidity. It is thought that the failure of the polarizing plate can be suppressed by the extension of the optical film.

Therefore, the present invention which is a specific means for solving the above-mentioned subject is as follows.

<1>
A step of forming a coating layer on a temporary support and drying to form a transfer film having an optical film formed on the temporary support,
Attaching a polarizer to the air interface side surface of the optical film in the transfer film;
It is a manufacturing method of the polarizing plate which has the process of exfoliating the above-mentioned temporary support from the above-mentioned transfer film,
The optical film contains 25 to 45% by mass of a copolymer containing a structural unit derived from butadiene based on the total solid content of the optical film,
The optical film contains 0.1 to 10% by mass of a polyester-based additive based on the total solid content of the optical film;
The thickness of the optical film is 4 to 10 μm,
The elongation at break of the optical film is 2.5% or more in an environment of 25 ° C. in a sample with a thickness of 30 μm and a width of 10 mm,
The manufacturing method of the polarizing plate whose arithmetic mean roughness of the surface of the side which forms the said optical film of the said temporary support body is 40 nm or less.
<2>
The manufacturing method of the polarizing plate as described in <1> in which the said optical film contains styrene resin.
<3>
The manufacturing method of the liquid crystal display device which has the process of bonding together the said optical film side of the polarizing plate manufactured by the manufacturing method as described in <1> or <2> on the liquid crystal cell side.
<4>
An optical film comprising a copolymer containing a structural unit derived from butadiene, and a polyester-based additive,
The content of the copolymer containing a structural unit derived from butadiene is 25 to 45% by mass with respect to the total solid content of the optical film,
The content of the polyester-based additive is 0.1 to 10% by mass with respect to the total solid content of the optical film,
The thickness of the optical film is 4 to 10 μm,
The optical film whose breaking elongation of the said optical film is 2.5% or more in a 25 degreeC environment in the sample of thickness 30 micrometers and width 10 mm.
<5>
The optical film as described in <4> containing styrene resin.

According to the present invention, a method of manufacturing a polarizing plate capable of suppressing breakage failure under high temperature and high humidity and suppressing unevenness in luminance when applied to an image display device, a method of manufacturing a liquid crystal display device having the above polarizing plate, and The optical film which can suppress the destructive failure of a polarizing plate under high humidity, and can suppress a brightness nonuniformity when it applies to an image display can be provided.

The contents of the present invention will be described in detail. Although the description of the configuration requirements described below may be made based on the representative embodiments of the present invention, the present invention is not limited to such embodiments. In the present specification, “to” is used in the meaning including the numerical values described before and after it as the lower limit value and the upper limit value.
In the present invention, "(meth) acrylic group" is used in the meaning of "either or both of an acrylic group and a methacrylic group". The same applies to “(meth) acrylic acid”, “(meth) acrylamide”, “(meth) acryloyl group” and the like.

The manufacturing method of the polarizing plate of the present invention is
A step of forming a coating layer on a temporary support and drying to form a transfer film having an optical film formed on the temporary support,
Attaching a polarizer to the air interface side surface of the optical film in the transfer film;
It is a manufacturing method of the polarizing plate which has the process of exfoliating the above-mentioned temporary support from the above-mentioned transfer film,
The optical film contains 25 to 45% by mass of a copolymer containing a structural unit derived from butadiene based on the total solid content of the optical film,
The optical film contains 0.1 to 10% by mass of a polyester-based additive based on the total solid content of the optical film;
The thickness of the optical film is 4 to 10 μm,
The elongation at break of the optical film is 2.5% or more in an environment of 25 ° C. in a sample with a thickness of 30 μm and a width of 10 mm,
It is a manufacturing method of a polarizing plate whose arithmetic mean roughness of the surface of the side which forms the above-mentioned optical film of the above-mentioned temporary support body is 40 nm or less.
Moreover, the optical film of the present invention is
An optical film comprising a copolymer containing a structural unit derived from butadiene, and a polyester-based additive,
The content of the copolymer containing a structural unit derived from butadiene is 25 to 45% by mass with respect to the total solid content of the optical film,
The content of the polyester-based additive is 0.1 to 10% by mass with respect to the total solid content of the optical film,
The thickness of the optical film is 4 to 10 μm,
It is an optical film whose breaking elongation of the said optical film is 2.5% or more in a 25 degreeC environment in the sample of thickness 30 micrometers and width 10 mm.

<Optical film>
The optical film of the present invention can be used in various applications. As an example of the use of the optical film of this invention, using as a structural member of a polarizing plate is mentioned.
When the optical film of the present invention is used as a member constituting a polarizing plate, it can be used as a film for protecting a polarizer (also referred to as "polarizing plate protective film"). It is preferable to use as a polarizing plate protective film of the side located in the display apparatus side through an adhesive especially.

When the optical film of the present invention is used as a polarizing plate protective film in a polarizing plate, the breakage failure of the polarizing plate can be suppressed under high temperature and high humidity.
The polarizing plate using the optical film of the present invention is preferably placed under conditions of 60 ° C. and 90% relative humidity as high-temperature and high-humidity conditions, for example.
The destruction of the polarizing plate is caused by the fact that the polarizing plate protective film is destroyed by the fact that the PVA-based resin, which is a polarizer, absorbs moisture and elongates under high temperature and high humidity, and simultaneously extends from under room temperature due to temperature rise. Become. This destruction may occur when the polarizing plate protective film becomes thin, specifically 10 μm or less.

The optical film of the present invention has the property of having a breaking elongation at 25 ° C. of 2.5% or more (that is, having high extensibility) in a sample form having a thickness of 30 μm and a width of 10 mm. By having this characteristic, the optical film of the present invention is used as a polarizing plate protective film to suppress destruction of the polarizing plate under high temperature and high humidity. More preferably, the breaking elongation is 3.0% or more, and further preferably 3.5% or more. The upper limit of the elongation at break is not particularly limited, but is preferably 25% or less.

In the present invention, the elongation at break is measured in a dry state (25 ° C., relative humidity 60%) using a sample having a thickness of 30 μm, a width of 10 mm, and a length of 120 mm. Using this tensile testing machine Tensilon RTC-1210A (Orientech Co., Ltd.), the breaking elongation is measured at a tension rate of 300 mm / min and a load cell 50N setting. The above measurement is carried out 5 times, and the results of 3 times excluding the maximum value and the minimum value are averaged to give a breaking elongation.
Although the film thickness of the optical film in the present invention is 4 to 10 μm, it was decided to measure the elongation at break of a 30 μm-thick sample so that the test can be stably carried out in the measurement of the elongation at break. The sample with a thickness of 30 μm can be formed, for example, by using a coating composition for producing an optical film, adjusting to a thickness of 30 μm and laminating an optical film less than 30 μm, etc. It can be made.

<Component having extensibility>
The optical film of the present invention can contain appropriately selected components having extensibility.
Specifically, the components having extensibility include ABS resin (acrylonitrile-butadiene-styrene resin), SB resin (styrene-butadiene resin), isoprene resin, butadiene resin, isobutyene-isobutene resin, polyether-urethane resin , Silicone resins, and the like. In addition, the above resin may be appropriately hydrogenated.
The optical film of the present invention preferably contains, as a component having extensibility, a copolymer including a structural unit derived from butadiene.
The optical film of the present invention preferably contains an ABS resin or an SB resin, and more preferably contains an SB resin.

The SB resin that can be used for the optical film of the present invention is not particularly limited, but specifically, commercially available ones can be used. For example, TR2000, TR2003, TR2250 (all manufactured by JSR Corporation), Clearene 210M, 220M, 730V (above, Denka Co., Ltd. product), Asaflex 800S, 805, 810, 825, 830, 840 (above, Asahi Kasei Co., Ltd. product), Eporex SB2400, SB2610, SB2710 (above, Sumitomo Chemical Co., Ltd.) Inc.), etc. can be mentioned.

The optical film of the present invention preferably contains 15 to 95% by mass, more preferably 20 to 50% by mass of the component having extensibility in the total solid content of the optical film, and still more preferably 25 It is to contain up to 45% by mass.
In addition, the total solid of an optical film means all the components except a solvent among the components contained in an optical film.
The optical film of the present invention preferably comprises 25 to 45% by mass, more preferably 25 to 40% by mass, of a copolymer containing a structural unit derived from butadiene based on the total solid content of the optical film. It is further more preferable that the content be 30% by mass.

The component having extensibility itself preferably has an elongation at break of 10% or more at 25 ° C. in a sample form having a thickness of 30 μm and a width of 10 mm consisting of 100 wt% of the component having extensibility by itself And 20% or more is more preferable.

<Component to control the removability from the substrate>
The optical film of the present invention can include, in the method of producing a polarizing plate of the present invention, a component for controlling the releasability in the step of peeling from the temporary support. By controlling the releasability of the optical film from the temporary support (base material), it is possible to prevent the formation of a peeling mark on the optical film after peeling, and to appropriately cope with the processing speed of the peeling step. It is possible to obtain favorable effects on the quality and productivity improvement of the

In the optical film of the present invention, a component for controlling the releasability can be appropriately selected. The optical film of the present invention preferably has a component for controlling the releasability from the polyester-based polymer film, as it is preferable to use a polyester-based polymer film as a temporary support as described later. As a component for controlling the releasability, it is preferable to use a polyester-based additive.

The polyester-based additive can be obtained by a known method such as dehydration condensation reaction of polybasic acid and polyhydric alcohol, or addition of dibasic acid anhydride to polyhydric alcohol and dehydration condensation reaction, and preferably It is a polycondensed ester formed from a dibasic acid and a diol.

The weight average molecular weight (Mw) of the polyester-based additive is preferably 500 to 50000, more preferably 750 to 40000, and still more preferably 2000 to 30000.
The weight average molecular weight of the polyester-based additive is preferably 500 or more in view of brittleness and wet heat durability, and is preferably 50000 or less in view of compatibility with the resin.
The weight average molecular weight of polyester type additive measured the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of standard polystyrene conversion on condition of the following. In addition, Mn is a number average molecular weight of standard polystyrene conversion.
GPC: gel permeation chromatograph (HLC-8220GPC manufactured by Tosoh Corp .; column; guard column HXL-H manufactured by Tosoh Corp.) TSK gel G7000HXL, two TSK gel GMHXL, TSK gel G2000HXL sequentially, eluent: tetrahydrofuran , Flow rate: 1 mL / min, sample concentration: 0.7 to 0.8 mass%, sample injection amount: 70 μL, measurement temperature: 40 ° C., detector; differential refraction (RI) meter (40 ° C.), standard substance; Co., Ltd. TSK standard polystyrene)

As a dibasic acid which comprises a polyester type additive, dicarboxylic acid can be mentioned preferably.
Examples of dicarboxylic acids include aliphatic dicarboxylic acids and aromatic dicarboxylic acids, and aromatic dicarboxylic acids or a mixture of aromatic dicarboxylic acids and aliphatic dicarboxylic acids can be preferably used.

Among the aromatic dicarboxylic acids, aromatic carboxylic acids having 8 to 20 carbon atoms are preferable, and aromatic dicarboxylic acids having 8 to 14 carbon atoms are more preferable. Specifically, it is selected from phthalic acid, isophthalic acid, and terephthalic acid Preferably, at least one of them is used.

Among the aliphatic dicarboxylic acids, aliphatic dicarboxylic acids having 3 to 8 carbon atoms are preferable, and aliphatic dicarboxylic acids having 4 to 6 carbon atoms are more preferable. Specifically, succinic acid, maleic acid, adipic acid, and glutar acid are preferable. At least one selected from acids is preferable, and at least one selected from succinic acid and adipic acid is more preferable.

Moreover, as diol which comprises a polyester type additive, aliphatic diol, an aromatic diol, etc. are mentioned, Especially aliphatic diol is preferable.
Among the aliphatic diols, aliphatic diols having 2 to 4 carbon atoms are preferable, and aliphatic diols having 2 to 3 carbon atoms are more preferable.
Examples of aliphatic diols include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol and the like, which may be used alone. Or it can use together and use two or more types.

The polyester-based additive is particularly preferably a compound obtained by condensing an aliphatic diol with at least one selected from phthalic acid, isophthalic acid and terephthalic acid.

The end of the polyester based additive may be sealed by reacting with a monocarboxylic acid. As a monocarboxylic acid used for sealing, aliphatic monocarboxylic acids are preferable, acetic acid, propionic acid, butanoic acid, benzoic acid and derivatives thereof are preferable, acetic acid or propionic acid is more preferable, and acetic acid is most preferable.

Examples of commercially available polyester-based additives include ester-based resin polyester resin (for example, LP050, TP290, LP035, LP033, TP217, TP220) manufactured by Japan Synthetic Chemical Industry Co., Ltd., ester-based resin Byron manufactured by Toyobo Co., Ltd. (for example, Byron 245) , Byron GK 890, Byron 103, Byron 200, Byron 550, Byron GK 880, Byron GK 680), and the like.

In the optical film of the present invention, the content of the component (preferably a polyester-based additive) for controlling the releasability from the substrate is 0.1% by mass or more based on the total solid content of the optical film Preferably, the content is 0.15% by mass or more, and more preferably 0.2% by mass or more. In addition, the content of the component (preferably a polyester-based additive) for controlling the releasability from the substrate is preferably 10% by mass or less, and 8% by mass or less, based on the total solid content of the optical film The content is more preferably 7.5% by mass or less. The above range is preferable from the viewpoint of obtaining appropriate adhesion together with the releasability from the base material.

<Leveling agent>
The optical film in the present invention can contain at least one leveling agent.
Thereby, in the process of forming an application layer on a temporary support and drying to produce a transfer film having an optical film, film thickness unevenness and the like caused by drying variation due to local distribution of drying wind is suppressed. And improve the repelling of the coated material.

As the leveling agent, for example, at least one leveling agent selected from silicone-based leveling agents and fluorine-based leveling agents can be used. The leveling agent is preferably an oligomer or a polymer rather than a low molecular weight compound.

When the leveling agent is added, the leveling agent moves quickly on the surface of the applied coating film and becomes unevenly distributed, and the leveling agent will be unevenly distributed on the surface even after drying of the coated film, so a film to which the leveling agent is added Surface energy is reduced by the leveling agent. The surface energy of the film is preferably low from the viewpoint of preventing film thickness nonuniformity, repelling, and nonuniformity.

Preferred examples of the silicone-based leveling agent include polymers or oligomers having a plurality of dimethylsilyloxy units as repeating units and having a substituent at the terminal and / or side chain. The polymer or oligomer containing dimethylsilyloxy as a repeating unit may contain structural units other than dimethylsilyloxy. The substituents may be the same or different and are preferably a plurality. Preferred examples of the substituent include groups containing a polyether group, an alkyl group, an aryl group, an aryloxy group, a cinnamoyl group, an oxetanyl group, a fluoroalkyl group, a polyoxyalkylene group, and the like.

The number average molecular weight of the silicone leveling agent is not particularly limited, but is preferably 100,000 or less, more preferably 50,000 or less, particularly preferably 1,000 to 30,000, and 1,000 to 20,000. Most preferably.

As an example of a preferable silicone type leveling agent, as a commercially available silicone type leveling agent which does not have an ionizing radiation curing group, Shin-Etsu Chemical Co., Ltd. X22-3710, X22-162C, X22-3701E, X22160AS, X22170DX, X224015. X22176DX, X22-176F, X224272, KF8001, X22-2000, etc .; FM4421, FM0425, FMDA26, FS1265 etc. made by Chisso Corporation; BY16-750, BY16880, BY16848, SF8427, made by Toray Dow Corning Corporation. SF8421, SH3746, SH8400, SF3771, SH3749, SH3748, SH8410, etc .; TSF series manufactured by Momentive Performance Materials Japan Ltd. (TSF 4460, TSF 4440, TSF 4445, TSF 4446, TSF 4453, TSF 4452, TSF 4730, TSF 4770, etc.), FGF 502, SILWET series (SILWETL 77, SILWETL 2 780, SILWETL 7608, SILWETL 7001, SILWETL 7002 SILWETL7600, SILWETL7602, SILWETL7604, SILWETL7604, SILWETL7605, SILWETL7607, SILWETL7622, SILWETL7644, S LWETL7650, SILWETL7657, SILWETL8500, SILWETL8600, SILWETL8610, SILWETL8620, SILWETL720) is not limited thereto but can be exemplified.

As those having an ionizing radiation curing group, X22-163A, X22-173DX, X22-163C, KF101, X22164A, X24-8201, X22174DX, X22164C, X222426, X222445, X222457, X222245, X22245 X22-163A manufactured by Shin-Etsu Chemical Co., Ltd. , X221602, X221603, X22164E, X22164B, X22164C, X22164D, TM0701 etc .; Silyoplane series (FM0725, FM0721, FM7725, FM7721, FM7726, FM7727 etc.) manufactured by Chisso Corporation; SF8411 manufactured by Toray Dow Corning Co., Ltd. , SF 8413, BY16-152D, BY16-152, BY16-152C, 8388A, etc .; Evonik Degussa TEGO Rad 2010, 2011, 2100, 2200 N, 2300, 2500, 2600, 2700 etc. manufactured by N Inc .; BYK 3500 manufactured by Bick Chemie Japan Ltd .; KNS 5300 manufactured by Shin-Etsu Silicone Co., Ltd .; Momentive Performance Materials Japan Ltd. Although UVHC1105, UVHC8550 etc. made from can be mentioned, it is not limited to this.

The fluorine-based leveling agent comprises a fluoroaliphatic group and a hydrophilic group which contributes to the affinity to various compositions such as coating and molding materials when, for example, this leveling agent is used as an additive. These compounds are compounds having the same molecule, and such compounds can be generally obtained by copolymerizing a monomer having a fluoroaliphatic group and a monomer having a hydrophilic group.
Representative examples of the monomer having a hydrophilic group, which is copolymerized with the monomer having a fluoroaliphatic group, include poly (oxyalkylene) acrylate, poly (oxyalkylene) methacrylate and the like.

As preferable commercially available fluorine-based leveling agents, Megafac series (MCF 350-5, F 472, F 476, F 445, F 444, F 443, F 178, F 470, F 475, F 479, manufactured by DIC Corporation) as having no ionizing radiation curing group. , F477, F482, F486, TF1025, F478, F178-F, F552 etc .; Neos Co., Ltd.'s lidagent series (FTX 218, 250, 245 M, 209 F, 222 F, 245 F, 208 G, 218 G, 240 G, 206 D, 240 D, etc.) and having an ionizing radiation curing group, Optool DAC manufactured by Daikin Industries, Ltd .; Defensor series manufactured by DIC (TF 3001, TF 3000, TF 3004, TF 3028, TF3). 27, TF3026, TF3025, etc.), RS series (RS71, RS101, RS102, RS103, RS104, RS105, etc.) are exemplified but not limited thereto.

In addition, compounds described in JP-A-2004-331812 and JP-A-2004-163610 can also be used.

The leveling agent is preferably contained in an amount of 0.01 to 5.0% by mass, more preferably 0.01 to 2.0% by mass, in the total solid content of the optical film. It is most preferable to contain 1.0% by mass.

<Solvent>
The optical film of the present invention can be obtained by drying a coated layer formed by applying a composition for forming an optical film.
The composition for optical film formation can contain a solvent (solvent). The solvent (preferably, an organic solvent) can dissolve or disperse the material for forming the optical film, can easily form a uniform surface state in the coating step and the drying step, can ensure the liquid storage property, and is moderately saturated It can select suitably from a viewpoint of having steam pressure etc. Examples of such an organic solvent include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate Methyl ethyl carbonate, 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, acetic acid Propyl, methyl propionate, ethyl propionate, γ-butyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2 Methoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate, 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 And toluene, xylene and the like, and can be used singly or in combination of two or more.

Among the above solvents, it is preferable to use at least one selected from dimethyl carbonate, methyl acetate, ethyl acetate, methyl ethyl ketone, acetyl acetone, acetone, toluene and xylene, and it is more preferable to use any of dimethyl carbonate, ethyl acetate and toluene Preferably, it is particularly preferred to use ethyl acetate.

It is preferable to use a solvent so that the solid concentration of the composition for forming an optical film is in the range of 5 to 80% by mass, more preferably 6 to 75% by mass, and still more preferably 7 to 70% by mass It is.

<Other ingredients>
The optical film of the present invention can contain other components from the viewpoint of improving other performances.

In the optical film of the present invention, characteristic values other than those described above are not particularly limited, and performance equivalent to that of a general known polarizing plate protective film can be appropriately mounted. It is preferable to appropriately have the performance required for a so-called inner film disposed between the liquid crystal panel and the liquid crystal panel. Specific property values can include haze related to display characteristics, light transmittance, spectral characteristics, wet heat durability of retardation, etc., and dimensional changes associated with wet heat thermos related to mechanical characteristics and polarizing plate processing suitability Rate, glass transition temperature, equilibrium moisture absorption rate, moisture permeability, contact angle, etc. can be mentioned.

In the optical film of the present invention, in order to appropriately impart the required performance to the above-mentioned so-called inner film, it is preferable to include the polymer resin described below.

<Polymer resin>
The polymer resin is not particularly limited. Specific examples include cyclic olefin resins, styrene resins, polyester resins, polycarbonate resins, vinyl resins, polyimide resins, polyarylate resins, etc., and cyclic polyolefin resins and styrene resins And from the viewpoint of appropriately imparting the performance required for the inner film.

As an example of cyclic olefin resin, it is a thermoplastic resin which has a unit of a monomer which consists of cyclic olefins, such as norbornene and a polycyclic norbornene monomer, for example, and is also called thermoplastic cyclic olefin resin. The cyclic olefin resin may be a hydrogenated product of the above ring-opening polymer of cyclic olefin or ring-opening copolymer using two or more cyclic olefins, cyclic olefin, chain olefin, vinyl It may be an addition polymer with an aromatic compound having a polymerizable double bond such as a group. A polar group may be introduced into the cyclic olefin resin.

When the protective film is made of a copolymer of a cyclic olefin and an aromatic compound having a chain olefin and / or a vinyl group, ethylene, propylene and the like are used as the chain olefin, and an aromatic having a vinyl group As the group compound, styrene, α-methylstyrene, nuclear alkyl substituted styrene and the like are used. In such a copolymer, the unit of the cyclic olefin monomer may be 50 mol% or less, preferably about 15 to 50 mol%. In particular, when a terpolymer of a cyclic olefin, a chain olefin and an aromatic compound having a vinyl group is used as a protective film, the unit of the monomer comprising the cyclic olefin may be relatively small as described above. it can. In such a ternary copolymer, the unit of monomers consisting of chain olefins is usually 5 to 80 mol%, and the unit of monomers consisting of aromatic compounds having a vinyl group is usually 5 to 80 mol%.

As the cyclic olefin-based resin, any commercially available product can be used. For example, “TOPAS” manufactured by TOPAS ADVANCED POLYMERS GmbH, Germany, and sold by Polyplastics Co., Ltd. in Japan, from JSR Co., Ltd. "Arton" sold, "ZEONOR" (ZEONOR) sold by Nippon Zeon Co., Ltd., and "Apel" sold by Mitsui Chemical Co., Ltd. (all of which are listed above) Trade name) etc. can be mentioned.

As an example of a styrene resin, the resin containing 50 mass% or more of styrene monomers is said. Here, the styrenic monomer refers to a monomer having a styrene skeleton in its structure.

Specific examples of styrenic resins may be homopolymers of styrene or derivatives thereof, and binary or higher copolymers of styrene or derivatives thereof with other copolymerizable monomers. Good. Here, a styrene derivative is a compound in which another group is bound to styrene, and examples thereof include o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, Alkylstyrene such as p-ethylstyrene, hydroxystyrene, hydroxystyrene, tert-butoxystyrene, vinylbenzoic acid, o-chlorostyrene, styrene such as p-chlorostyrene, hydroxyl group, alkoxy group, carboxyl group, halogen at benzene nucleus And substituted styrene etc. into which
The styrenic resin is preferably a homopolymer of styrene (that is, polystyrene). When the copolymer is a copolymer with another copolymerizable monomer, the styrenic resin is a copolymer of styrene or a styrene derivative and at least one monomer selected from acrylonitrile, maleic anhydride, methyl methacrylate and butadiene. It is preferable to be combined.

Although various things can be used as a polystyrene, It is preferable that it is GPPS grade. In general, GPPS grade polystyrene is due to its high transparency. Examples of the index indicating the degree of polymerization of polystyrene include a melt mass flow rate measured by melt flow, a melt volume flow rate, and a weight average molecular weight (Mw) measured by gel permeation chromatography.

The polystyrene used in the present invention preferably has a melt mass flow rate of 18 g / 10 min or less (200 ° C., 5 kgf under pressure, 1 kgf = 9.807 N). More preferably, it is 7.5 g / 10 min or less, still more preferably 1.9 g / 10 min or less. When the melt mass flow rate is 18 g / 10 min or less, the degree of polymerization of polystyrene is high, which is advantageous for suppressing the breakage failure of the polarizing plate.

The polystyrene used in the present invention preferably has a Mw of 180000 or more. More preferably, it is 350000 or more. When Mw is 180,000 or more, the degree of polymerization of polystyrene is high, which is advantageous for suppressing the breakage failure of the polarizing plate.
Preferred polystyrenes include CR-3500, CR-4500, CR-2600, XC-315, XC-515 manufactured by DIC Corporation, HF77, 679, SGP-10 manufactured by PS Japan Co., Ltd., G200C, G210C manufactured by Toyo Styrene Co., Ltd. , G320C, HRM12, HRM26, HRM48N, and the like, but it is not limited thereto.

Further, styrene resins include those obtained by copolymerizing styrene monomer components with other monomer components. As copolymerizable monomers, alkyl methacrylates such as methyl methacrylate, cyclohexyl methacrylate, methyl phenyl methacrylate, isopropyl methacrylate, etc .; methyl acrylate, ethyl acrylate, Unsaturated carboxylic acid alkyl ester monomers such as alkyl acrylates such as butyl acrylate, 2-ethylhexyl acrylate and cyclohexyl acrylate; methacrylic acid, acrylic acid, itaconic acid, maleic acid, fumaric acid Unsaturated carboxylic acid monomers such as cinnamic acid; unsaturated dicarboxylic acid anhydride monomers which are anhydrides such as maleic anhydride, itaconic acid, ethyl maleic acid, methyl itaconic acid, chlormaleic acid; acrylonitrile, methacryl acid Unsaturated nitrile monomers such as ronitrile; 1,3-butadiene, 2-methyl- 2,3-Butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, conjugated dienes such as 1,3-hexadiene, and the like, and copolymerization of two or more of them. Is also possible.

The styrene-based resin that can be suitably used in the present invention may be a styrene / acrylonitrile copolymer, a styrene / methacrylic acid copolymer, or a styrene / maleic anhydride copolymer because the heat resistance is high. .
In addition, since the styrene / acrylonitrile copolymer, styrene / methacrylic acid copolymer, and styrene / maleic anhydride copolymer have high compatibility with the acrylic resin, the optical film of the present invention contains the acrylic resin. And the like are also preferable from the viewpoint of obtaining an optical film which has high transparency and causes phase separation during use to reduce the transparency. From such a point of view, it is particularly preferable to use a polymer containing methyl methacrylate as a monomer component as the acrylic resin.

In the case of a styrene-acrylonitrile copolymer, the copolymer proportion of acrylonitrile in the copolymer is preferably 1 to 40% by mass. A further preferred range is 1 to 30% by mass, and a particularly preferred range is 1 to 25% by mass. When the proportion of the acrylonitrile copolymer in the copolymer is 1 to 40% by mass, it is preferable because the transparency is excellent.
In the case of a styrene-methacrylic acid copolymer, the copolymer proportion of methacrylic acid in the copolymer is preferably 0.1 to 50% by mass. A more preferable range is 0.1 to 40% by mass, and a further preferable range is 0.1 to 30% by mass. It is excellent in heat resistance that the copolymer ratio of methacrylic acid in a copolymer is 0.1 mass% or more, and excellent in transparency if it is 50 mass% or less, it is preferable.
In the case of a styrene-maleic anhydride copolymer, the proportion of maleic anhydride copolymer in the copolymer is preferably 0.1 to 50% by mass. A more preferable range is 0.1 to 40% by mass, and a further preferable range is 0.1% to 30% by mass. It is excellent in heat resistance that the maleic anhydride content in a copolymer is 0.1 mass% or more, and since it is excellent in transparency if it is 50 mass% or less, it is preferable.

As the styrene resin, plural kinds of resins having different compositions, molecular weights and the like can be used in combination.
The styrenic resin can be obtained by a known anionic, bulk, suspension, emulsification or solution polymerization method. Further, in the styrene resin, the unsaturated double bond of the benzene ring of the conjugated diene or the styrene monomer may be hydrogenated. The hydrogenation rate can be measured by nuclear magnetic resonance (NMR).

Examples of the polycarbonate resin include polycarbonate, a polycarbonate containing a structural unit in which bisphenol A is fluorene-modified, and a polycarbonate containing a structural unit in which bisphenol A is 1,3-cyclohexylidene-modified.
Examples of vinyl resins include polyethylene, polypropylene, polystyrene, polyvinylidene chloride, polyvinyl alcohol and the like.

In the optical film of the present invention, the content of the polymer resin is preferably 5 to 55% by mass, more preferably 5 to 45% by mass, with respect to the total solid content of the optical film. The content is further preferably 35% by mass, particularly preferably 7 to 30% by mass, and most preferably 10 to 25% by mass.

<Adhesive improvement component of optical film to polarizer>
By including an adhesive property improvement component of the optical film to the polarizer as another component, in the polarizing plate having the optical film of the present invention, the adhesion of the optical film to the polarizer can be improved.

The optical film of the present invention is a copolymer comprising a repeating unit represented by the following general formula (I) and a repeating unit represented by the following general formula (II) as an adhesive property improving component of the optical film to a polarizer. It may contain a crosslinking reaction product derived from coalescence (hereinafter also referred to as “copolymer (a)”) and / or copolymer (a).
The optical film of the present invention may contain only one of either the copolymer (a) or the crosslinking product derived from the copolymer (a), or may contain both of them. Good.

In formula (I), R ¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R ² represents an alkyl group having at least one fluorine atom as a substituent, or —Si (R ^a3 ) (R ^a4 L represents a group containing O-, L represents -O-,-(C = O) O-, -O (C = O)-, a divalent aliphatic chain group, and a divalent aliphatic cyclic group And at least one divalent linking group selected from the group consisting of R ^a3 and R ^a4 each independently represent an alkyl group which may have a substituent or an aryl group which may have a substituent.

In formula (II), R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ¹¹ and R ¹² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted group R ¹¹ represents an unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R ¹¹ and R ¹² may be linked. X ¹ represents a divalent linking group.

<Cross-linked product derived from copolymer (a) or copolymer (a)>
Hereinafter, the crosslinking reaction product derived from the copolymer (a) contained in the optical film or the copolymer (a) will be described.

R ¹ in the general formula (I) represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and a hydrogen atom or an alkyl group having 1 to 4 carbon atoms More preferred is a hydrogen atom or a methyl group.

R ² in the general formula (I) is preferably an alkyl group (fluoroalkyl group) having at least one fluorine atom as a substituent, and is preferably a fluoroalkyl group having 1 to 20 carbon atoms, and 1 to 18 carbon atoms Is more preferably a fluoroalkyl group, and more preferably a fluoroalkyl group having 2 to 15 carbon atoms. The number of fluorine atoms in the fluoroalkyl group is preferably 1 to 25, more preferably 3 to 21, and most preferably 5 to 21.

L in the general formula (I) consists of -O-,-(C = O) O-, -O (C = O)-, a divalent aliphatic chain group, and a divalent aliphatic cyclic group Represents a divalent linking group composed of at least one selected from the group consisting of In addition,-(C = O) O- represents that a carbon atom on R ¹ side and C = O are bonded and R ² and O are bonded, and -O (C = O)-is a group on R ¹ side And a carbon atom of the formula (I) bond to O, and R ² and a C = O bond.
As the divalent aliphatic chain group represented by L, an alkylene group having 1 to 20 carbon atoms is preferable, and an alkylene group having 1 to 10 carbon atoms is more preferable.
The divalent aliphatic cyclic group represented by L is preferably a cycloalkylene group having 3 to 20 carbon atoms, and more preferably a cycloalkylene group having 3 to 15 carbon atoms.
As L,-(C = O) O- or -O (C = O)-is preferable, and-(C = O) O- is more preferable.

The repeating unit represented by the general formula (I) is particularly preferably a repeating unit represented by the following general formula (III), from the viewpoint of the surface uneven distribution advantageous to the adhesion and the radical polymerization property.

In formula (III), R ¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, ma and na each independently represent an integer of 1 to 20, and X represents a hydrogen atom or a fluorine atom.

^{R 1} in the general formula (III) is the general formula (I) in the same meaning as ^{R 1,} and preferred ranges are also the same.

Ma and na in the general formula (III) each independently represent an integer of 1 to 20.
From the viewpoint of surface uneven distribution advantageous for adhesion and easiness of raw material acquisition and production, ma in general formula (III) is preferably an integer of 1 to 8, and an integer of 1 to 5 More preferable. Also, na is preferably an integer of 1 to 15, more preferably an integer of 1 to 12, still more preferably an integer of 2 to 10, and most preferably an integer of 5 to 7.

X in the general formula (III) represents a hydrogen atom or a fluorine atom, preferably a fluorine atom.

The repeating unit represented by the general formula (I) or (III) can be obtained by polymerization of a monomer, and preferred monomers include, for example, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3,3-Pentafluoropropyl (meth) acrylate, 2- (perfluorobutyl) ethyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 2- (perfluorooctyl) ) Ethyl (meth) acrylate, 2- (perfluorodecyl) ethyl (meth) acrylate, 2- (perfluoro-3-methylbutyl) ethyl (meth) acrylate, 2- (perfluoro-5-methylhexyl) ethyl (meth) acrylate ) Acrylate, 2- (perfluoro-7-methyloctyl) ethyl (meth) acrylate, 1H, 1H 3H-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 7H-dodecafluoroheptyl (meth) acrylate, 1H, 1H, 9H-hexadecafluorononyl (meth ) Acrylate, 1H-1- (Trifluoromethyl) trifluoroethyl (meth) acrylate, 1H, 1H, 3H-hexafluorobutyl (meth) acrylate, 3-perfluorobutyl-2-hydroxypropyl (meth) acrylate, 3 -Perfluorohexyl 2-hydroxypropyl (meth) acrylate, 3-perfluorooctyl 2-hydroxypropyl (meth) acrylate, 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl (meth) acrylate, 3 - Perfluoro-5-methylhexyl) -2-hydroxypropyl (meth) acrylate, 3- (perfluoro-7-methyl-octyl) -2-hydroxypropyl (meth) acrylate.

It is also preferable as another aspect that R ² in the general formula (I) has a repeating unit (polysiloxane structure) containing a siloxane bond represented by —Si (R ^a3 ) (R ^a4 ) O—. R ^a3 and R ^a4 may each independently have an alkyl group which may have a substituent (preferably an alkyl group having 1 to 12 carbon atoms which may have a substituent) or a substituent Represents an aryl group. In this case, the copolymer (a) is preferably a graft copolymer in which a polysiloxane structure is introduced into the side chain. The compound having a siloxane bond for obtaining the graft copolymer is more preferably a compound represented by the following general formula (IV).

R ^a3 and R ^a4 each independently represent an alkyl group, a haloalkyl group or an aryl group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. For example, a methyl group, an ethyl group and a hexyl group can be mentioned. The haloalkyl group is preferably a fluorinated alkyl group having 1 to 10 carbon atoms. For example, trifluoromethyl group and pentafluoroethyl group can be mentioned. The aryl group is preferably an aryl group having 6 to 20 carbon atoms. For example, a phenyl group and a naphthyl group can be mentioned. Among them, R ^a3 and R ^a4 are preferably a methyl group, a trifluoromethyl group or a phenyl group, and a methyl group is particularly preferable.
R ^a1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. R ^a5 is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.
nn is preferably 10 to 1000, more preferably 20 to 500, and still more preferably 30 to 200.
The nn R ^a3 's in the general formula (IV) may be the same or different, and the nn R ^{a4' s} may be the same or different.

As a compound having a siloxane bond for graft copolymerization, one end (meth) acryloyl group-containing polysiloxane macromer (for example, Silaprene 0721, 0725 (all trade names, manufactured by JNC Co., Ltd.), AK-5, AK-30, AK-32 (all trade names, manufactured by Toa Gosei Co., Ltd.), KF-100T, X-22-169AS, KF-102, X-22-3701 IE, X-22-164B, X- 22-164C, X-22-5002, X-22-173B, X-22-174D, X-22-167B, X-22-161AS (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. be able to.

Next, the following general formula (II) will be described.
The copolymer (a) has a repeating unit represented by the general formula (II) in addition to the repeating unit represented by the above general formula (I). The repeating unit represented by the general formula (II) has a strong interaction with a hydroxyl group. That is, when an adhesive layer having a hydroxyl group is provided on the surface of the coating solution after applying the coating solution of the composition for forming an optical film on the substrate, part of the repeating unit represented by the general formula (II) or The entire interaction with the hydroxyl group causes the copolymer (a) to diffuse and be adsorbed to the adhesive layer interface having the hydroxyl group and the inside of the adhesive layer.
Therefore, after the optical film and the adhesive layer are in contact with each other, the copolymer (a) having the repeating unit represented by the general formula (II) added to the coating solution is an optical film, an adhesive layer, and A copolymer having the same chemical structure as that of the general formula (II) or a derivative having a structure in which the repeating unit represented by the general formula (II) is reacted with the hydroxyl group of the adhesive layer (crosslinking reaction Exist as
As such, since the copolymer having the repeating unit represented by the general formula (II) interacts with the adhesive layer, regardless of the ratio of the copolymer present in the adhesive layer and / or the optical film. The adhesion between the optical film containing the copolymer (a) and the adhesive layer can be enhanced.

In formula (II), R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ¹¹ and R ¹² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted group R ¹¹ represents an unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R ¹¹ and R ¹² may be linked. X ¹ represents a divalent linking group.

In formula (II), R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and a hydrogen atom or an alkyl group having 1 to 4 carbon atoms More preferred is a hydrogen atom or a methyl group.

The substituted or unsubstituted aliphatic hydrocarbon group represented by R ¹¹ and R ¹² in the general formula (II) includes a substituted or unsubstituted alkyl group, an alkenyl group and an alkynyl group. Specific examples of the above alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group and hexadecyl group. Octadecyl group, eicosyl group, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, 1 And-linear, branched or cyclic alkyl groups such as adamantyl group and 2-norbornyl group.
Specific examples of the above alkenyl group include linear or branched such as vinyl group, 1-propenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 1-cyclopentenyl group, 1-cyclohexenyl group and the like And cyclic or cyclic alkenyl groups.
Specific examples of the above alkynyl group include ethynyl group, 1-propynyl group, 1-butynyl group, 1-octynyl group and the like.

A substituted or unsubstituted R ¹¹ and R ¹² represent each, specific examples of the aryl group include phenyl group. Further, those in which 2 to 4 benzene rings form a condensed ring, and those in which a benzene ring and an unsaturated 5-membered ring form a condensed ring can be mentioned, and specific examples thereof include a naphthyl group, an anthryl group, A phenanthryl group, an indenyl group, an acenabutenyl group, a fluorenyl group, a pyrenyl group etc. are mentioned.
Moreover, as an example of the substituted or unsubstituted heteroaryl group represented by R ¹¹ and R ¹² respectively, a hydrogen on a heteroaromatic ring containing one or more hetero atoms selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom Included are those in which one atom is removed to form a heteroaryl group. Specific examples of the heteroaromatic ring containing one or more hetero atoms selected from the group consisting of nitrogen atom, oxygen atom and sulfur atom include pyrrole, furan, thiophene, pyrazole, imidazole, triazole, oxazole, isoxazole, oxadiazole Thiazole, Thiadiazole, Indole, Carbazole, Benzofuran, Dibenzofuran, Thianaphtene, Dibenzothiophene, Indazole Benzimidazole, Anthranil, Benzisoxazole, Benzoxazole, Benzothiazole, Purine, Pyridine, Pyridazine, Pyrimidin, Pyrazine, Triazine, Quinoline, Acridine, Isoquinoline, phthalazine, quinazoline, quinoxaline, naphthyridine, phenanthroline, pteridine and the like can be mentioned.

R ¹¹ and R ¹² may be linked, and in this case, R ¹¹ and R ¹² each independently represent an alkyl group or an aryl group, which are preferably linked to each other, R More preferably, ¹¹ and R ¹² are alkyl groups, which are linked to each other.

Examples of the divalent linking group represented by X ¹ include-(C = O) O-, -O (C = O)-,-(C = O) NH-, -O-, -CO-,- NH -, - O (C = O) -NH -, - O (C = O) -O-, and -CH ₂ - comprises at least one linking group selected from, and the number of carbon atoms is 7 or more Is preferred.

R ¹¹ , R ¹² and X ¹ may be optionally substituted by one or more substituents. Examples of the substituent include monovalent nonmetallic atomic groups other than hydrogen atoms, and are selected from, for example, the following Substituent Group Y.
Substituent group Y:
Halogen atom (-F, -Br, -Cl, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, aryldithio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group , N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-ally N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group, acylamino group, N -Alkylacylamino group, N-aryl Silamino group, ureido group, N'-alkyl ureido group, N ', N'-dialkyl ureide group, N'-aryl ureido group, N', N'- diaryl ureido group, N'-alkyl-N'- aryl ureido Group, N-alkyl ureido group, N-aryl ureido group, N'-alkyl-N-alkyl ureido group, N'-alkyl-N-aryl ureido group, N ', N'-dialkyl-N-alkyl ureido group, N ', N'-dialkyl-N-aryl ureido group, N'-aryl-N-alkyl ureido group, N'-aryl-N-aryl ureido group, N', N'-diaryl-N-alkyl ureido group, N ', N'-diaryl-N-aryl ureido group, N'-alkyl-N'-aryl-N-alkyl ureido group, N'-alkyl-N'-aryl-N-aryl ureido , Alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl- N-aryloxy carbonylamino group, formyl group, acyl group, carboxyl group and its conjugate base group, alkoxycarbonyl group, aryloxy carbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N- arylcarbamoyl group, N, N- di arylcarbamoyl group, N- alkyl -N- arylcarbamoyl group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfo group _(-SO 3 H)及The conjugated base group, alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfina Moyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfone Famoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group and its conjugate base group, N-alkylsulfonylsulfamoyl group (-SO ₂ NHSO ₂ (alkyl)) and its conjugation base group, N- aryl sulfonylsulfamoyl group _(-SO 2 NHS ₂ (aryl)) and its conjugated base group, N- alkylsulfonylcarbamoyl group _(-CONHSO 2 _(alkyl)) and its conjugated base group, N- aryl sulfonyl carbamoyl group _(-CONHSO 2 _(aryl)) and its conjugated base group , Alkoxysilyl group (-Si (Oalkyl) ₃ ), aryloxysilyl group (-Si (Oaryl) ₃ ), hydroxysilyl group (-Si (OH) ₃ ) and its conjugate base group, phosphono group (-PO ₃ H) ₂₎ and its conjugated base group, a dialkyl phosphono group _(-PO 3 _(alkyl) 2), diaryl phosphono group _(-PO 3 _(aryl) 2), alkyl aryl phosphono group _(-PO 3 _{(alkyl) (aryl} )), monoalkyl phosphono group _(-PO 3 H _(alkyl)) and its conjugated base group Monoarylphosphono group _(-PO 3 H (aryl)) and its conjugated base group, a phosphonooxy group (-OPO ₃ H ₂₎ and its conjugated base group, a dialkyl phosphono group _{(-OPO 3 (alkyl) 2)} , Diaryl phosphonooxy group (-OPO ₃ (aryl) ₂ ), alkyl aryl phosphonooxy group (-OPO ₃ (alkyl) (aryl)), monoalkyl phosphonooxy group (-OPO ₃ H (alkyl)) and the same Conjugated base groups, monoarylphosphonooxy groups (—OPO ₃ H (aryl)) and conjugated base groups thereof, cyano groups, nitro groups, aryl groups, alkenyl groups and alkynyl groups.
In addition, these substituents may combine with each other or with a substituted hydrocarbon group to form a ring, if possible.

R ¹¹ and R ^{12 in} general formula (II) each independently represent a hydrogen atom or an alkyl group, or are both alkyl groups and are preferably bonded to each other to form a ring, R ¹¹ and R ¹² It is preferred that both are hydrogen atoms, or are both alkyl groups and bonded to each other to form a ring.

From the viewpoint of adhesion, the repeating unit represented by the general formula (II) is preferably a repeating unit represented by the following general formula (V). The adhesion improvement by the repeating unit represented by the general formula (V) is presumed to be due to the effect of bringing the polarity close to the adhesive layer having a hydroxyl group.

In formula (V), R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ¹¹ and R ¹² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted group R ¹¹ represents an unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R ¹¹ and R ¹² may be linked. X ¹¹ is at least one selected from the group consisting of-(C = O) O-, -O (C = O)-,-(C = O) NH-, -O-, -CO-, -CH _2- It represents a divalent linking group composed of one. X ¹² is — (C = O) O—, —O (C = O) —, — (C = O) NH—, —O—, —CO—, —NH—, —O (C = O) — NH -, - O (C = O) -O -, - CH 2 - comprises at least one linking group selected from, and represents a divalent linking group or a substituted or unsubstituted aromatic ring containing at least one . However, the total number of carbon atoms in the ^{X 11} and the ^{X 12} is 7 or more.

As X ¹¹ in the general formula (V),-(C = O) O-, -O (C = O)-,-(C = O) NH- is preferable, and-(C = O) O- is Most preferred.
X ¹² preferably contains 1 to 5 aromatic rings, more preferably 2 to 4 aromatic rings, and most preferably 2 to 3 aromatic rings.
Each preferred range of ^{R 10, R 11} and ^{R 12} in the general formula (V) are the same as ^{R 10, R 11} and ^{R 12} in the general formula (II).

The repeating unit represented by Formula (II) or (V) is more preferably a repeating unit represented by the following Formula (VI).

In formula (VI), R ¹⁰ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ¹¹ and R ¹² each independently represent a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted group R ¹¹ represents an unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and R ¹¹ and R ¹² may be linked. X ²¹ represents — (C = O) O— or — (C = O) NH—. X ²² represents — (C = O) O—, —O (C = O) —, — (C = O) NH—, —O—, —CO—, —NH—, —O (C = O) — A divalent linking group containing at least one linking group selected from NH-, -O (C = O) -O-, -CH _2- , and X ²² includes a substituted or unsubstituted aromatic ring It may be

Each preferred range of the general ^R 10 in formula ^{(VI), R 11} and ^{R 12} are the same as ^{R 10, R 11} and ^{R 12} in the general formula (II).

The repeating units represented by the general formulas (II), (V) or (VI) can be obtained by polymerization of monomers. Specific examples of preferable monomers giving the repeating unit represented by the general formula (II), (V) or (VI) are shown, but not limited thereto.

Further, the copolymer (a) optionally has a repeating unit (other repeating units) other than the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II) It may be done.

Other types of monomers that give other repeating units are described in Polymer Handbook 2nd ed. , J. Brandrup, Wiley lnterscience (1975) Chapter 2 Page 1-43. For example, acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, dialkyl itaconates, dialkyl esters of fumaric acid or monoalkyl esters The compound etc. which have one addition polymerization unsaturated bond chosen from etc. can be mentioned.

Specifically, the following monomers can be mentioned as a monomer which gives other repeating units.
Acrylic esters:
Methyl acrylate, ethyl acrylate, propyl acrylate, chlorethyl acrylate, 2-hydroxyethyl acrylate, trimethylolpropane monoacrylate, benzyl acrylate, methoxybenzyl acrylate, phenoxyethyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 2- Acryloyl oxyethyl succinate, 2-carboxyethyl acrylate, etc.,
Methacrylic acid esters:
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, trimethylolpropane monomethacrylate, benzyl methacrylate, methoxybenzyl methacrylate, phenoxyethyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, ethylene glycol Monoacetoacetate monomethacrylate, 2-methacryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl succinate, 2-methacryloyloxyethyl hexahydrophthalic acid, 2-carboxyethyl methacrylate, etc.

Acrylamides:
Acrylamide, N-alkyl acrylamide (having 1 to 3 carbon atoms as alkyl, such as methyl, ethyl and propyl), N, N-dialkyl acrylamide (having 1 to 6 carbons as alkyl), N-hydroxyethyl-N-methyl acrylamide, N-2-acetamidoethyl-N-acetyl acrylamide and the like.
Methacrylamides:
Methacrylamide, N-alkyl methacrylamide (having 1 to 3 carbon atoms as alkyl, such as methyl, ethyl and propyl), N, N-dialkyl methacrylamide (having 1 to 6 carbons as alkyl) N-hydroxyethyl-N-methyl methacrylamide, N-2-acetamidoethyl-N-acetyl methacrylamide and the like.
Allylic compound:
Allyl esters (eg allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate etc.), allyloxyethanol etc.

Vinyl ethers:
Alkyl vinyl ethers (eg hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethyl butyl vinyl ether, hydroxyethyl vinyl ether, Diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc. Vinyl esters:
Vinyl acetate, vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl barrate, vinyl caproate, vinyl chloroacetate, vinyl dichloro acetate, vinyl methoxy acetate, vinyl butoxy acetate, vinyl lactate, vinyl- β-phenyl butyrate, vinyl cyclohexyl carboxylate and the like.

Itaconic acid dialkyls:
Dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.
Dialkyl esters or monoalkyl esters of fumaric acid: dibutyl fumarate and the like.

As monomers giving other repeating units, crotonic acid, itaconic acid, acrylonitrile, methacrylonitrile, maleironitrile, styrene, 4-vinylbenzoic acid, styrene macromer (AS-6S manufactured by Toagosei Co., Ltd.), methyl methacrylate Macromer (AA-6 manufactured by Toa Gosei Co., Ltd.) may also be mentioned. It is also possible to convert the structure of the polymer after polymerization by polymer reaction.

The copolymer (a) preferably has a thermally crosslinkable group. The thermally crosslinkable group is a group which causes a crosslinking reaction by heating to crosslink, and specific examples thereof include a carboxyl group, an oxazoline group, a hydroxyl group, an isocyanate group, a maleimide group, an acetoacetoxy group, an epoxy group, amino and the like. It can be mentioned. The copolymer (a) preferably contains a repeating unit having a thermally crosslinkable group.

The copolymer (a) is particularly preferably thermally crosslinked with other compounds contained in the optical film, in particular, a styrenic resin. The copolymer (a) can be immobilized on the surface of the optical film by the copolymer (a) and the styrenic resin each having a thermally crosslinkable group which is mutually reactive, and the optical film and the other films can be immobilized. It is possible to develop higher adhesion with layers, membranes, films or other articles.

The content of the repeating unit represented by the general formula (I) in the copolymer (a) is preferably 5 to 95% by mass, and 8 to 90% by mass, based on the total mass of the copolymer (a) Is more preferable, and 10 to 85% by mass is more preferable.

The content of the repeating unit represented by the general formula (II) in the copolymer (a) is preferably 0.5 to 80% by mass, based on the total mass of the copolymer (a), and 1 to 75 % By mass is more preferable, and 2 to 70% by mass is even more preferable.

The content of the repeating unit having a thermally crosslinkable group in the copolymer (a) is preferably 0.5 to 80% by mass, and preferably 1 to 75% by mass, based on the total mass of the copolymer (a). More preferably, 2 to 70% by mass is more preferable.

The weight average molecular weight (Mw) of the copolymer (a) is preferably 1000 to 200000, more preferably 1800 to 150000, still more preferably 2000 to 150000, particularly preferably 2500 to 140000, and very preferably 20000 to 120000.
The number average molecular weight (Mn) of the copolymer (a) is preferably 500 to 160000, more preferably 600 to 120000, still more preferably 600 to 100000, particularly preferably 1000 to 80000, and very preferably 2000 to 60000.
The dispersion degree (Mw / Mn) of the copolymer (a) is preferably 1.00 to 18.00, more preferably 1.00 to 16.00, still more preferably 1.00 to 14.00, and 1. 00 to 12.00 are particularly preferred, and 1.00 to 10.00 are very particularly preferred.
The weight average molecular weight and the number average molecular weight are values measured by gel permeation chromatography (GPC) under the following conditions.
[Eluent] N-methyl-2-pyrrolidone (NMP)
[Equipment name] EcoSEC HLC-8320GPC (made by Tosoh Corporation)
[Column] TSKgel Super AWM-H (made by Tosoh Corporation)
[Column temperature] 40 ° C
[Flow rate] 0.50 ml / min

The copolymer (a) can be synthesized by a known method.

Although the specific example of a copolymer (a) is shown below, it is not limited to these.

The optical film of the present invention may or may not contain the copolymer (a), but when it is contained, the copolymer (a) does not impair the function of the optical film, From the viewpoint of strengthening the adhesion to the adhesive, when the total solid content (all components excluding the solvent) of the optical film of the present invention is 100% by mass, the content is preferably 0.0001 to 40% by mass. The content is more preferably 0.001 to 20% by mass, and still more preferably 0.005 to 10% by mass.

<Adhesive improvement resin of optical film to polarizer>
An adhesion improving resin different from the copolymer (a) may be contained as an adhesion improving component of the optical film to the polarizer. The adhesion improving resin preferably has a heat-crosslinkable group, and the adhesion improving resin preferably comprises a repeating unit derived from a styrenic monomer. The thermally crosslinkable group is the same as that described for the above-mentioned copolymer (a). When the styrene resin has a thermally crosslinkable group and the copolymer (a) has a thermally crosslinkable group, the copolymer (a) is immobilized on the surface of the functional film It is possible to develop higher adhesion. In this case, since the copolymer (a) can be immobilized on the surface of the functional film by reacting the thermally crosslinkable group by heating, a compound (monomer) having a reactive group in the molecule is contained. And, since the process of fixing the copolymer (a) to the surface of the functional film becomes unnecessary by curing the monomer by irradiation of ionizing radiation such as ultraviolet rays, it is preferable.

Although the specific example of the styrene resin which has a thermally crosslinkable group is given to the following, this invention is not limited to this.

The adhesion-improving resin may be used alone or in combination of two or more kinds having different repeating unit compositions, molecular weights and the like as the adhesion-improving resin.
The adhesion improving resin can be obtained by known anionic, bulk, suspension, emulsion or solution polymerization methods. In addition, in the adhesion improving resin, the unsaturated double bond of the benzene ring of a conjugated diene or a styrenic monomer may be hydrogenated. The hydrogenation rate can be measured by nuclear magnetic resonance (NMR).
A commercial item can also be used as the adhesion improving resin, and examples thereof include Epocross RPS-1005: styrene-oxazoline copolymer (manufactured by Nippon Shokubai).

The optical film of the present invention may or may not contain the adhesion improving resin, but when it is contained, the adhesion improving resin is relative to the total solid content of the optical film of the present invention. The content is preferably 0.0001 to 60% by mass, more preferably 0.001 to 55% by mass, and still more preferably 0.005 to 50% by mass.

<Configuration of optical film>
The optical film of the present invention may be a single film or have a laminated structure of two or more layers.

<Film thickness>
The film thickness of the optical film preferable in the present invention is 3 to 20 μm, more preferably 3 to 15 μm, still more preferably 4 to 10 μm, particularly preferably 4 to 7 μm, and most preferably 4 to 6 μm. By setting the film thickness to 4 μm or more, it is possible to sufficiently suppress the destruction of the polarizing plate by the optical film extending sufficiently to the polarizer extension under high temperature and high humidity, and by setting the thickness to 10 μm or less It is preferable at the point which can be thinned. In addition, it is preferable because the effect of reducing light unevenness of the liquid crystal display device due to environmental change and the effect of reducing warpage of the liquid crystal panel due to temperature change can be expected when the liquid crystal display device is mounted.

<Production of optical film>
The optical film of the present invention can be produced using a known solution film forming method or melt extrusion method. Moreover, when laminating | stacking an optical film on a base material, you may produce simultaneously with a base material (co-casting or co-extrusion). In addition, it can be prepared by a method of forming a coating layer with a coating solution for forming an optical film by a known method on a temporary support prepared separately, and in a state where a polymer solution or a coating layer is appropriately laminated on a substrate, The temporary support can also be stretched. In particular, it is preferable to use a coating method.

The optical film can be formed on the temporary support by the following coating method. Dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method, slide coating method, extrusion coating method (die coating method) (refer to JP-A-2003-164788), A known method such as a microgravure coating method is used, and among them, the microgravure coating method and the die coating method are preferable. When forming an optical film by a coating method, the drying process which volatilizes a solvent, and the thermal crosslinking process which bridge | crosslinks a thermally crosslinkable group can be used suitably.

<Material of temporary support>
As a material for forming a temporary support used in the transfer film of the present invention, in addition to the viewpoints of mechanical strength, surface roughness, thermal stability, etc., it may be selected by adhesion (adhesive force) with the optical film. it can.

A well-known raw material and film can be used suitably as such a temporary support body. Specific examples of the material include polyester polymers, olefin polymers, cycloolefin polymers, (meth) acrylic polymers, cellulose polymers, and polyamide polymers.
In particular, polyester-based polymers and olefin-based polymers are preferable as the material of the base film, polyester-based polymers are more preferable, and among polyester-based polymers, polyethylene terephthalate (PET) is particularly preferable.

Although the surface energy of the temporary support is not particularly limited, the relationship between the surface energy of the material of the optical film and the coating solution and the surface energy of the surface of the temporary support on which the optical film is formed is adjusted. By doing this, the adhesion between the optical film and the temporary support can be adjusted. If the surface energy difference is reduced, the adhesive force tends to increase, and if the surface energy difference is increased, the adhesive force tends to decrease and can be set appropriately.

From the contact angle values of water and methylene iodide, the surface energy of the temporary support can be calculated using the method of Owens. For example, DM 901 (a contact angle meter manufactured by Kyowa Interface Science Co., Ltd.) can be used to measure the contact angle.
The surface energy of the temporary support on the side of forming the optical film is preferably 41.0 to 48.0 mN / m, and more preferably 42.0 to 48.0 mN / m. It is preferable that the surface energy is 41.0 mN / m or more, because the uniformity of the thickness of the optical film can be enhanced, and the peeling force of the optical film to the temporary support is suitably within the range of 48.0 mN / m or less. Because it is easy to control

On the surface of the temporary support, in order to control the adhesion to the optical film, a release agent may be applied in advance. The optical film can be used after peeling off the temporary support after being bonded to the polarizer through an adhesive or a pressure-sensitive adhesive in a later step. The optical properties and mechanical properties can be adjusted by appropriately stretching the temporary support together with the optical film laminated on the temporary support.

<Surface unevenness of temporary support>
In the present invention, the surface of the temporary support on which the optical film is to be formed preferably has an arithmetic average roughness (Ra) of 40 nm or less, more preferably 0.1 to 38 nm, and 1 to 36 nm. It is further preferred that
Arithmetic mean roughness (Ra) in the present invention is based on Japanese Industrial Standard (JIS) B0601: 2013.
By setting Ra to 40 nm or less, the recess depth on the optical film side becomes small, and it is possible to suppress the breakage of the polarizing plate due to the extension of the polarizer under high temperature and high humidity. Moreover, it is preferable also from a viewpoint of suppressing the nonuniformity in the visual field of the haze related to the display characteristic of an optical film, light transmittance, a spectral characteristic, etc. Moreover, blocking in a roll form can be prevented by Ra being 0.1 nm or more. The Ra of the present invention can be obtained, for example, by measuring 465.48 μm long and 620.64 μm wide using a non-contact surface / layer cross-sectional shape measurement system VertScan 2.0 (manufactured by Ryoka Systems Co., Ltd.) Can. Further, as another index, the height of the surface convex portion on the optical film side of the temporary support is preferably 0.1 to 10.0 μm. The height of the surface convex portion of the temporary support can be measured, for example, by observing the cross-sectional image of the temporary support with an optical microscope and observing the height of the convex portion protruding from the flat portion. . By setting the surface convex portion to 10.0 μm or less, the depth of the concave portion on the optical film side can be reduced, and the breakage due to the extension of the polarizer under high temperature and high humidity can be suppressed.

<Film thickness of temporary support>
The thickness of the temporary support used to form the optical film by the coating method is preferably 5 to 100 μm, more preferably 10 to 75 μm, and still more preferably 15 to 55 μm. When the film thickness is 5 μm or more, sufficient mechanical strength is easily secured, and a failure such as curl, wrinkle, or buckling does not easily occur, which is preferable. In addition, when the transfer film of the optical film of the present invention and the temporary support is stored, for example, in the form of a long roll, the surface pressure applied to the transfer film is adjusted to an appropriate range as the film thickness is 100 μm or less. It is preferable because it is easy to cause and adhesion failure does not easily occur. Thicknessing processing can also be given to both ends as appropriate.

<Thicking processing>
The temporary support used in the transfer film of the present invention is provided with a thickening process at both ends. Thickening (also referred to as knurling) means to impart unevenness to a substrate by embossing or the like from one side or both sides of a temporary support, and a known method can be used. The height of the thickness setting processing to be applied can be appropriately adjusted according to the thickness of the optical film, and is, for example, 0.2 to 5.5 μm, and preferably 0.5 to 5.0 μm. 0 to 4.5 μm is more preferable, and 1.5 to 4.0 μm is more preferable. After laminating the temporary support alone or the optical film, the height of the thickness forming process is obtained by cutting out the thickness forming part of the most pressed part and measuring the height of unevenness with a thickness meter.
The position of thickness processing is preferably 0 to 10% relative to the substrate from both ends of the substrate, more preferably 0.1 to 7%, and still more preferably 0.3 to 5%. The width of the thickness forming process is preferably 3 to 40 mm, more preferably 5 to 30 mm, and still more preferably 10 to 25 mm.

<Transfer film>
The transfer film on which the optical film is coated is composed of at least a temporary support and an optical film, and is referred to as a transfer film as one integrated.
The transfer film can adhere the optical film to other layers, films, films or other articles, and in particular can bond the optical film to the polarizer through the adhesive layer, and the obtained polarizing plate Although the temporary support can be peeled off from the optical film or can be used as it is as a part of the polarizing plate without peeling off, the temporary support can be peeled off from the optical film from the viewpoint of thinning the polarizing plate. It is preferable to use it.

<Peeling Force Between Optical Film and Temporary Support>
When the optical film used in the polarizing plate of the present invention is formed by a coating method, the peeling force between the optical film and the temporary support is determined by the material of the optical film, the material of the temporary support, and the internal strain of the optical film. Etc. can be adjusted and controlled. The peeling force can be measured, for example, by a test in which the temporary support is peeled in the direction of 90 ° with respect to the surface of the optical film, and the peeling force when measured at a speed of 300 mm / min is 0.001 to 5N. / 25 mm is preferable, 0.01 to 3 N / 25 mm is more preferable, and 0.05 to 1 N / 25 mm is more preferable. If it is 0.001 N / 25 mm or more, peeling of the temporary support in the peeling step can be prevented, and if it is 5 N / 25 mm or less, peeling failure in the peeling step (eg, dipping or cracking of the optical film) You can prevent.

<Polarizer>
The polarizing plate in the present invention includes at least a polarizer and the optical film of the present invention. In the polarizing plate, the polarizer and the optical film of the present invention may be bonded via an adhesive layer.

<Polarizer>
The polarizers include iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. The iodine based polarizer and the dye based polarizer are generally produced using a polyvinyl alcohol based film. Any polarizer may be used in the present invention. For example, the polarizer is preferably composed of polyvinyl alcohol (PVA) and a dichroic molecule. For the polarizer composed of polyvinyl alcohol (PVA) and a dichroic molecule, the description in JP-A-2009-237376 can be referred to, for example. The film thickness of the polarizer is usually 1 to 50 μm, preferably 2 to 30 μm, and more preferably 3 to 20 μm.

<Polarizer protective film>
The optical film of the present invention may be further bonded to the opposite surface of the surface to which the optical film of the present invention is bonded to the polarizer, or even if a polarizing plate protective film known in the prior art is bonded. Good.
The conventionally known polarizing plate protective film is not particularly limited with respect to any of the optical properties and materials, but includes a cellulose ester resin, an acrylic resin, and / or a cyclic olefin resin, a polyester resin (or a main component Film) can be preferably used, and an optically isotropic film or an optically anisotropic retardation film may be used.
As a polarizing plate protective film conventionally known, as a thing containing cellulose ester resin, Fujitac TD40UC (made by Fujifilm Co., Ltd.) etc. can be utilized, for example.
The polarizing plate protective film conventionally known includes, as a film containing an acrylic resin, a polarizing plate protective film containing a (meth) acrylic resin containing a styrene resin described in Japanese Patent No. 4570042, Japanese Patent No. 5041532 A polarizing plate protective film containing a (meth) acrylic resin having a glutarimide ring structure described in claim 1 in the main chain, a polarizing plate containing a (meth) acrylic resin having a lactone ring structure described in JP2009-122664A A film, a polarizing plate protective film containing a (meth) acrylic resin having a glutaric anhydride unit described in JP-A-2009-139754 can be used.
As the polarizing plate protective film conventionally known, as a film containing cyclic olefin resin, cyclic olefin resin film described in paragraph [0029] or later of JP 2009-237376 A, JP 4881827 A, JP JP The cyclic olefin resin film containing the additive which reduces Rth of the 2008-063536 gazette can be utilized.
As a film containing a polyester resin, a conventionally known polarizing plate protective film can be exemplified by Cosmo Shine SRF (Toyobo Co., Ltd.) made of polyethylene terephthalate.

Bonding Optical Film to Polarizer
An optical film is used as a protective film of a polarizing plate. The polarizing plate can be produced by a known method, and is preferably produced by bonding so that the transport direction of the polarizer and the transport direction of the transfer film are parallel.

At this time, the optical film may be subjected to surface treatment (described in JP-A-6-94915 and JP-A-6-118232) to make it hydrophilic, and for example, glow discharge treatment, corona discharge treatment, or alkali It is preferable to carry out saponification treatment and the like. Corona discharge treatment is most preferably used as the surface treatment.

The transfer film in the present invention can be used by laminating the polarizer with a polarizer in the polarizing plate processing step via an adhesive or a pressure-sensitive adhesive, peeling off the temporary support, leaving only the optical film on the polarizing plate.

<Adhesive layer>
The adhesive layer may be formed of an adhesive. As the adhesive, an adhesive containing a resin having a hydroxyl group is preferable, and in addition to a polyvinyl alcohol-based adhesive, an epoxy-based active energy ray-curable adhesive, for example, a molecule as shown in JP-A 2004-245925 An adhesive containing an epoxy compound which does not contain an aromatic ring and curing by heating or irradiation of active energy rays, the total amount of (meth) acrylic compounds described in JP-A-2008-174667 is 100 parts by mass ( a1) A (meth) acrylic compound having two or more (meth) acryloyl groups in the molecule, and (b) a (meth) acrylic compound having a hydroxyl group in the molecule and having only one polymerizable double bond , (C1) containing phenol ethylene oxide modified acrylate or nonyl phenol ethylene oxide modified acrylate Such as sexual energy ray-curable adhesive. Among these, polyvinyl alcohol adhesives are most preferred.
The polyvinyl alcohol-based adhesive is an adhesive containing modified or non-modified polyvinyl alcohol. The polyvinyl alcohol-based adhesive may contain a crosslinking agent in addition to the modified or unmodified polyvinyl alcohol. Specific examples of the adhesive include aqueous solutions of polyvinyl alcohol or polyvinyl acetal (eg, polyvinyl butyral), and latexes of vinyl polymers (eg, polyvinyl chloride, polyvinyl acetate, polybutyl acrylate). A particularly preferred adhesive is an aqueous solution of polyvinyl alcohol. At this time, polyvinyl alcohol is preferably completely saponified.
Further, the epoxy-based active energy ray-curable adhesive can be crosslinked with the copolymer (a) because the epoxy group is opened by irradiation of active energy rays to form a hydroxyl group. Therefore, in the present invention, an epoxy-type active energy ray-curable adhesive is also included as a hydroxyl group-containing adhesive and can be used appropriately.

For example, epoxy-based active energy ray-curable adhesives are disclosed in JP-A-2012-140610, JP-A-2012-140610, JP-A-2013-213214, JP-A-2015-40283, and JP-A-2015-. Those described in JP-A-143,352 and JP-A-2015-187744 can be used as appropriate.

Polymerization of Thermally Crosslinkable Group
The heat treatment for polymerization of the thermally crosslinkable group of the optical film of the present invention described above can be carried out in the step of bonding a polarizer to the air interface side surface of the optical film in the transfer film. Moreover, after laminating | stacking a polarizer, the adhesion | attachment between an optical film and a polarizer can be improved by giving heat processing time as a thermal crosslinking process further.

The thermal crosslinking step is a heating step to accelerate the reaction of the thermal crosslinking group, and is not particularly limited as long as it does not impair the properties of the optical film, but preferably 40 to 200 ° C., more preferably 50. ~ 130 ° C. The temperature is preferably 50 ° C. or more from the viewpoint of facilitating the progress of the reaction, and is preferably 130 ° C. or less from the viewpoint of suppressing the deformation of the resin used for the substrate.
The time required for heating varies depending on the type and amount of the thermally crosslinkable site group used, but is preferably 5 seconds to 1 hour, more preferably 10 seconds to 30 minutes, still more preferably 15 seconds to 5 minutes. 15 seconds or more are preferable in the viewpoint which makes reaction advance more easily, and 5 minutes or less are preferable in the viewpoint which heightens productivity.

<Method of manufacturing polarizing plate>
The manufacturing method of the polarizing plate of the present invention is
A step of forming a coating layer on a temporary support and drying to form a transfer film having an optical film formed on the temporary support,
Attaching a polarizer to the air interface side surface of the optical film in the transfer film;
It is a manufacturing method of the polarizing plate which has the process of exfoliating the above-mentioned temporary support from the above-mentioned transfer film,
The optical film contains 25 to 45% by mass of a copolymer containing a structural unit derived from butadiene based on the total solid content of the optical film,
The optical film contains 0.1 to 10% by mass of a polyester-based additive based on the total solid content of the optical film;
The thickness of the optical film is 4 to 10 μm,
The elongation at break of the optical film is 2.5% or more in an environment of 25 ° C. in a sample with a thickness of 30 μm and a width of 10 mm,
It is a manufacturing method of a polarizing plate whose arithmetic mean roughness of the surface of the side which forms the above-mentioned optical film of the above-mentioned temporary support body is 40 nm or less.

The temporary support and the polarizer used in the method for producing a polarizing plate of the present invention are the same as those described above.
In addition, regarding the coating solution for forming an optical film, the component contained in the coating solution such as a copolymer containing a structural unit derived from butadiene, a polyester-based additive, other components, etc. or a component which may be included is the same as described above. It is. The coating method of the coating solution is also the same as described above.
The thickness of the optical film, the breaking elongation and the like are also the same as those described above.

In the method for producing a polarizing plate of the present invention, the method for drying the coating layer formed on the temporary support is not particularly limited and can be carried out by a known method.
Moreover, although the process of bonding a polarizer together on the optical film side surface in a transfer film can be performed by a well-known method, Preferably it is the same as that of what was mentioned above. The optical film side surface is usually the air interface side surface of the optical film.
The step of peeling the temporary support from the transfer film is not particularly limited and can be performed by a known method.

[Display device]
The present invention also relates to a display device including the polarizing plate of the present invention. The display device is not particularly limited, and may be a liquid crystal display device including a liquid crystal cell, an organic EL image display device including an organic EL layer, or a plasma image display device. The polarizing plate of the present invention can be disposed, for example, on the display surface side. As a configuration of the display device, any configuration of a known display device can be adopted.
It is preferable that the liquid crystal display device of the present invention further has a backlight, and the polarizing plate is disposed on the backlight side or the viewing side. There is no restriction | limiting in particular as a backlight, A well-known backlight can be used. The liquid crystal display device of the present invention is preferably laminated in the order of the backlight, the backlight side polarizing plate, the liquid crystal cell, and the viewing side polarizing plate.
As other configurations, any configuration of a known liquid crystal display device can be adopted. There is also no particular limitation on the mode (mode) of the liquid crystal cell, and a TN (Twisted Nematic) mode liquid crystal cell, a horizontal electric field switching IPS (In-Plane Switching) mode liquid crystal cell, and an FLC (Ferroelectric Liquid Crystal) mode liquid crystal cell Liquid crystal cell of AFLC (Anti-ferroelectric Liquid Crystal) system, liquid crystal cell of OCB (Optically Compensatory Bend) system, liquid crystal cell of STN (Supper Twisted Nematic) system, liquid crystal cell of VA (Vertically Aligned) system, and HAN (Hybrid Aligned Nematic) As a liquid crystal display device of various display methods such as a liquid crystal cell of the can do. Among them, in the liquid crystal display device of the present invention, the liquid crystal cell is preferably an IPS system.
As other configurations, any configuration of a known liquid crystal display device can be adopted.

The method for producing a liquid crystal display device of the present invention is a method for producing a liquid crystal display device, comprising the step of bonding the optical film side of the polarizing plate produced by the method for producing a polarizing plate of the present invention to the liquid crystal cell side. .

Hereinafter, the present invention will be more specifically described by way of examples. The materials, amounts used, proportions, treatment contents, treatment procedures and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Accordingly, the scope of the present invention is not limited to the specific examples shown below.

Synthesis Example 1
(Synthesis example of fluorine-containing copolymer (A-19))
In a 500 ml three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet, 23.3 g of cyclohexanone was charged, and the temperature was raised to 78 ° C. Then, 59.10 g (141.3 mmol) of 2- (perfluorohexyl) ethyl acrylate, 11.00 g (28.6 mmol) of 4- (4-acryloyloxybutoxy) benzoyloxyphenylboronic acid, 28.53 g of acrylic acid (299.1 mmol), 2.39 g (31.5 mmol) of 1,3-propanediol, 157.7 g of cyclohexanone, 52.5 g of isopropanol and 5.73 g of "V-601" (manufactured by Wako Pure Chemical Industries, Ltd.) The mixed solution consisting of the above was dropped at an equal speed so that the dropping was completed in 180 minutes. After completion of the dropwise addition, stirring is further continued for 1 hour, 1.00 g of V-601 is added, the temperature is raised to 90 ° C., and stirring is continued for further 3 hours, and a solution of fluorine-containing copolymer (A-19) in cyclohexanone I got 330.0 g. The weight average molecular weight (Mw) of this copolymer was measured at 5,700 (gel permeation chromatography (EcoSEC HLC-8320 GPC (made by Tosoh Corp.)) as eluent NMP, flow rate 0.50 ml / min, temperature 40 ° C. Under the conditions, it was calculated in terms of polystyrene, and the column used was TSKgel Super AWM-H × 3 (made by Tosoh Corp.). Further, the structure was identified by ¹ H-NMR spectrum of the obtained polymer, and the composition ratio was determined.
¹ H-NMR (CDCl ₃ ) δ: 3.8 to 4.5 (2H, 4H, methylene group in repeating units derived from 2- (perfluorohexyl) ethyl acrylate, derived from compound II-12 Derived from the methylene group of the unit, derived from the methylene group adjacent to the boron of the repeating unit derived from the compound II-12), 6.8 to 7.3 and 7.6 to 8.2 (8 H, derived from the compound II-12) Derived from the aromatic ring of the repeating unit).

Fluorinated copolymer (A-19)

The component ratio of the fluorine-containing copolymer (A-19) was the following ratio as a result of the structure identification in the ¹ H-NMR spectrum.
25 parts by weight of a repeating unit derived from 2- (perfluorohexyl) ethyl acrylate, 5 parts by weight of a repeating unit derived from 4- (4-acryloyloxybutoxy) benzoyloxyphenylboronic acid 1,3-dipropanol ester, acrylic acid 70 parts by weight of a repeating unit derived from

[Examples 1 to 12, Comparative Examples 1 to 7]
<Preparation of Coating Solution for Forming Optical Film>
Coating solutions 1-19 for forming an optical film were prepared with the compositions shown in Tables 1-2. In Tables 1 and 2, "%" represents "% by mass", the numerical values in the solvent represent the content of each solvent in all the solvents contained in the total amount of the coating liquid, and the numerical values in the other components represent the coating It represents the content in the components (total solids) excluding the solvent in the liquid. In addition, the total solid concentration of the coating solutions 1 to 19 for forming an optical film was 14.3% by mass.

The compounds described in Tables 1 to 2 are shown below.

(A) Copolymer containing a structural unit derived from butadiene-Asaflex 810 (manufactured by Asahi Kasei Co., Ltd.)
・ Clearen 220M (made by Denka Co., Ltd.)
・ TR 2250 (made by JSR Corporation)

(B) Polyester-based additive Byron 550 (Toyobo Co., Ltd.)
・ Byron GK 680 (made by Toyobo Co., Ltd.)

(C) Other components ・ F-552: Commercially available fluorine-based surface modifier (made by DIC Corporation, product name: Megafac F-552)
・ SGP-10: Polystyrene (made by PS Japan)
・ Epocross RPS-1005: Styrene-Oxazoline Copolymer (manufactured by Nippon Shokubai)

Solvent ・ Ethyl acetate ・ Toluene

Coating of Optical Film 1: Preparation of Optical Film A1 to A19
Using commercially available polyethylene terephthalate film, Emblet S38 (film thickness 38 μm, manufactured by UNITIKA CO., LTD.) As a base material and using coating liquids 1 to 19 so that the optical films A1 to A19 each have a film thickness of 30 μm It was made. Specifically, each coating solution is applied on a substrate at a transfer speed of 60 m / min by a die coating method using a slot die described in JP-A-2006-122889, Example 1; Dried for a second. Then it was rolled up. Thus, optical films A1 to A19 were produced. In addition, Ra of the surface of the side which forms the optical film of the said polyethylene terephthalate film was 34 nm.

The film thicknesses and breaking elongations of the produced optical films A1 to A19 were evaluated by the following methods.

<Film thickness>
The film thickness of the optical film is obtained by measuring the film thickness of a laminate (transfer film) manufactured using a contact film thickness meter KG30001 (manufactured by Anritsu Co., Ltd.), and subtracting the substrate thickness similarly measured therefrom. Calculated. The film thicknesses of the optical films A1 to A19 were all 30.0 μm.

<Breaking elongation>
The elongation at break measurement of the optical films A1 to A19 prepared above was performed according to the following. That is, using a tensile tester Tensilon RTC-1210A (Orientech Co., Ltd.), a sample is cut out to a width of 10 mm and a length of 120 mm in a dry state (25 ° C., relative humidity 60%), and an optical film is made of polyethylene terephthalate film. Peel and prepare. The breaking elongation of this sample is measured at a tension rate of 300 mm / min and a load cell 50N setting. The measurement is made 5 times for each sample, and the results of three times excluding the maximum value and the minimum value are averaged to give a breaking elongation.

<Coating of optical film 2: Preparation of optical films 1 to 19>
A commercially available polyethylene terephthalate film, Lumirror (R) S105 (film thickness 38 μm, manufactured by Toray Industries, Inc.) is used as a substrate (temporary support), and coating liquids 1 to 19 are used to form optical films 1 to 19, respectively. It produced so that thickness might be set to 5.0 micrometers. Specifically, each coating solution is applied on a substrate at a transfer speed of 60 m / min by a die coating method using a slot die described in JP-A-2006-122889, Example 1; Dried for a second. Then it was rolled up. Thus, optical films 1 to 19 with a polyethylene terephthalate film temporary support were produced. In addition, Ra of the surface of the side which forms the optical film of the said polyethylene terephthalate film was 34 nm.

<Peeling surface evaluation (presence of peeling mark)>
The peeled surfaces of the optical films 1 to 19 produced above were evaluated by the following method. That is, an acrylic adhesive (20 μm in thickness) is attached to a glass substrate of 50 mm in length × 50 mm in width × 0.7 mm in thickness. Then, the optical film (thickness 5.0 μm, with a polyethylene terephthalate film temporary support) is attached such that the optical film is adjacent to the adhesive. After peeling off the temporary support, the optical film is observed with illumination at an angle of 45 to 30 °, with the vertical position being 90 °. If the peeled surface is whitish (if the peeling mark is "presence"), it is judged that there is a problem with the quality.

Table 3 below shows the evaluation results of the type of coating solution for forming an optical film, the elongation at break of optics A1 to A19, and the peeling marks of optical films 1 to 19 used in each example and comparative example.

Using the coating liquid from which the optical film in which the peeling mark was "none" was obtained, preparation of the following polarizing plate and the mounting evaluation to a liquid crystal display device were performed.

[Examples 101 to 112, Comparative Examples 106 and 107]
Using the above coating solutions 1-4, 7, 9, 12 to 19 in the same manner as the coating 2 of the above optical film, an optical film 1 to 4, 7, 9, 12 to with a polyethylene terephthalate film temporary support 19 was produced.

<Preparation of polarizing plate protective film>
[Preparation of polymethyl methacrylate film]
According to Example 1 of JP-A-2015-227458, a polymethyl methacrylate film having a thickness of 40 μm was produced.

(surface treatment)
About the polymethyl methacrylate film produced above, corona discharge treatment was performed under the following conditions.
Electrode: VETAPONE Coron-Plus
Generator: CP1C
Output: 900 W
Film conveyance speed: 6 m / min About the polymethyl methacrylate film which performed the said process, the film of the roll form of width 1340 mm and length 100 m was obtained.

[Preparation of polyethylene terephthalate film]
According to the method for producing a polarizer protective film 1 of JP-A-2017-201417, a polyethylene terephthalate film having a thickness of 80 μm was produced.

(surface treatment)
About the polyethylene terephthalate film produced above, corona discharge treatment was performed under the following conditions.
Electrode: VETAPONE Coron-Plus
Generator: CP1C
Output: 900 W
Film conveyance speed: 6 m / min About the polyethylene terephthalate film which performed the said process, the film of the roll form of width 1340 mm and length 100 m was obtained.

[Production of Cellulose Acetate Film]
(Surface treatment of film)
After immersing a cellulose acetate film (Fuji Film Co., Ltd., Fujitac TD40 UC) in a 1.5 mol / L aqueous solution of sodium hydroxide (saponification liquid) adjusted to 37 ° C. for 1 minute, the film is washed with water and then 0 After immersion in a 0.5 mol / L aqueous solution of sulfuric acid for 30 seconds, it was further passed through a water washing bath. Then, water drainage was repeated three times, and after removing water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to prepare a saponified cellulose acetate film.

(Preparation of polarizer)
According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls, and the film was stretched in the longitudinal direction to prepare a polarizer with a thickness of 18 μm.

(Pasted together)
A polarizer was obtained using the following adhesive 1 using the thus obtained polarizer, the optical films 1 to 4, 7, 9, 12 to 19 with a temporary support, and the saponified cellulose acetate film. The film was laminated by roll-to-roll so that the absorption axis of the film and the longitudinal direction of each film were parallel. Here, one surface of the polarizer is such that the coated surface (optical film side surface) of any one of the optical films 1 to 4, 7, 9 and 12 to 19 with a temporary support is on the polarizer side. The other side of the polarizer was laminated with the saponified cellulose acetate film.

Adhesive 1:
A 3% aqueous solution of polyvinyl alcohol (PVA-117H, manufactured by Kuraray Co., Ltd.) was used as an adhesive.
When Adhesive 1 was used, it was cured by drying at 70 ° C. for 20 minutes after lamination.
・ Adhesive 2:
The ultraviolet curable adhesive of the composition shown below was produced.
Celloxide 2021P 25 parts by mass Aron oxetane OXT-221 50 parts by mass Rika Resin DME-100 25 parts by mass Photoacid generator 1 5 parts by mass

・ Ceroxide 2021 P: 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylic acid (manufactured by Daicel Co., Ltd.)
Aron oxetane OXT-221: 3-ethyl-3-[(3-ethyl oxetan-3-yl) methoxymethyl] oxetane (manufactured by Toagosei Co., Ltd.)
· Rica resin DME-100: 1,4-cyclohexanedimethanol diglycidyl ether [manufactured by Shin Nippon Rika Co., Ltd.]
-Photo acid generator 1: CPI 100P [San Apro Co., Ltd. product]
When Adhesive 2 is used, an ultraviolet ray with an illuminance of 200 mW / cm ² and an irradiation amount of 160 mJ / cm ² is irradiated at a temperature of 30 ° C. using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) And allowed to cure.

Following the above bonding, the polyethylene terephthalate film as a substrate (temporary support) was continuously peeled off using the same apparatus as the separator peeling apparatus to produce a polarizing plate.

<Mounting evaluation 1 for liquid crystal display>
The above-prepared polarizing plate was used as a front side polarizing plate and rear side polarizing plate of an IPS mode liquid crystal television (slim type 55 type liquid crystal television, backlight and cell clearance 0.5 mm) It was bonded to the liquid crystal cell via an adhesive so as to be disposed on the cell side. The obtained liquid crystal television is kept in an environment of 60 ° C. and relative humidity 90% for 3 days, then transferred to an environment of 25 ° C. and relative humidity 60% and lighted in a black display state to cause light leakage defects due to the polarization plate breakage. evaluated. Table 4 shows the results of evaluation of light leakage due to breakage of the polarizing plate.
(Evaluation of light leakage defects due to cracking of the polarizing plate in the front direction (destruction failure of the polarizing plate under high temperature and high humidity))
The light leakage defect (in other words, the crack of the polarizing plate) at the time of black display when observed from the front of the device was observed and evaluated according to the following criteria.
A: No light leakage is observed.
B: Light leakage is observed.

In each of Examples 1 to 12, the elongation at break was 4.1% or more, and there was no light leakage defect of the polarizing plate. In Comparative Examples 1 to 5, peeling marks were observed, and the optical film used for the polarizing plate was at a level to be discarded.
Next, Examples 101 to 112 were of satisfactory quality in which light leakage defects were not confirmed by lighting in a black display state. The light leakage defect was confirmed in Comparative Examples 106 and 107. It is considered that this is because the optical film is broken (i.e., the polarizing plate is broken) by the extension of the polarizer under high temperature and high humidity.

[Examples 201 to 203, Comparative Examples 201 and 202]
The optical films of Examples 201 to 203 and Comparative Examples 201 to 202 were obtained in the same manner as the optical film 1 except that the film thickness and the temporary support used were changed. The film thickness was produced with the film thickness described in Table 5. The temporary support was Emblet S38, and the surface asperity (Ra (nm)) was 34 nm as described in the table.
A polarizing plate was produced in the same manner as in Example 101 except that the above-mentioned optical film was used.
Using the produced polarizing plate, evaluation 1 for mounting on the liquid crystal display device and evaluation 2 for mounting on the following liquid crystal display device were performed.

<Mounting evaluation 2 for liquid crystal display>
The optical film produced as described above for the polarizing plate produced as the front side polarizing plate and rear side polarizing plate of an IPS mode liquid crystal television (slim type 55 type liquid crystal television, the clearance between the backlight and the cell is 0.5 mm) It was bonded to the liquid crystal cell via an adhesive so as to be disposed on the cell side. The obtained liquid crystal television is kept in an environment of 60 ° C. and relative humidity 90% for 3 days, then transferred to an environment of 25 ° C. and relative humidity 60% and kept on in a black state, and visually observed 24 hours later The light unevenness (brightness unevenness) caused by the panel warpage was evaluated.
(Uneven brightness level in the front direction)
Light unevenness (in other words, brightness unevenness) at the time of black display when observed from the front of the device was observed and evaluated according to the following criteria.
A: No unevenness is visually recognized at all under an environment of 100 lx B: Almost no unevenness is recognized under an environment of 100 lx C: Light unevenness is observed under an environment of 100 lx D: Clear under an environment of 100 lx Unevenness is visually recognized E: A clear unevenness is visually recognized under an environment of illuminance of 300 lx. It is preferable that it is a standard of A.

Examples 201 to 203 were of satisfactory quality with no light leakage defect and no luminance unevenness. In Comparative Example 201, it is considered that the film thickness of the optical film is thin, and a portion where the film thickness is particularly thin due to the surface unevenness of the temporary support is cracked and thus a light leakage defect is generated. Moreover, in Comparative Example 202, it is considered that uneven brightness was generated because the film thickness of the optical film was increased.

[Example 204, Comparative Example 203]
The same procedure as in Example 101 was repeated except that the temporary support was changed to Theonex Q51 (Ra 9 nm, film thickness 38 μm, Teijin DuPont Film Co., Ltd.), to obtain an optical film 20 (film thickness 5.0 μm) .
The same operation as in Example 101 was conducted except that the temporary support was changed to OPU-1 (Ra 76 nm, film thickness 38 μm, Mitsui Chemicals Tosoh Co., Ltd.), to obtain an optical film 21 (film thickness 5.0 μm) .
The polarizing plates of Example 204 and Comparative Example 203 were produced in the same manner as in Example 101 except that the above optical film was used, and the evaluation of mounting on a liquid crystal display device 1 and the evaluation of mounting on a liquid crystal display device 2 were performed. . The results are shown below.

Example 204 was of satisfactory quality with no light leakage defects and no luminance unevenness. Comparative Example 203 is considered to have caused a light leakage defect because the surface asperity of the temporary support was large and the portion where the film thickness of the optical film was particularly thin was broken.

[Examples 205 to 209]
<Production of Polarizing Plate>
A polarizing plate 301 was obtained in the same manner as in Example 101 except that the polarizing plate protective film was replaced with a cellulose acetate film to make the above-mentioned polymethyl methacrylate film.
A polarizing plate 302 was obtained in the same manner as in Example 101 except that the polarizing plate protective film was replaced with a cellulose acetate film to make the above-mentioned polyethylene terephthalate film.
In Example 101, the adhesive was changed to the adhesive 2 instead of the adhesive 1, and the same operation was performed except that the ultraviolet ray was irradiated and cured to obtain a polarizing plate 303.
In Example 101, the polarizing plate protective film is replaced with a cellulose acetate film to make the above-mentioned polymethyl methacrylate film, and the adhesive is replaced with the adhesive 1 to make the adhesive 2, and the same procedure is followed except that curing is performed by irradiating ultraviolet light. The following operation was performed to obtain a polarizing plate 304.
Example 101 is the same as Example 101 except that the polarizing plate protective film is replaced with a cellulose acetate film to form the above-mentioned polyethylene terephthalate film, and the adhesive is replaced by the adhesive 1 to form the adhesive 2 and irradiated with ultraviolet light to cure. The work was performed to obtain a polarizing plate 305.
The evaluations 1 and 2 of mounting to the liquid crystal display devices of Examples 205 to 209 were performed using the above polarizing plates. The results are shown below.

Examples 205 to 209 had satisfactory quality with no light leakage defect and no luminance unevenness.

From Tables 3 to 7 above, it was found that the optical film of the present invention is highly effective in suppressing the breakage of the polarizing plate under high temperature and high humidity. Moreover, it turned out that the liquid crystal display which comprises the polarizing plate which has an optical film of this invention can suppress a brightness nonuniformity.

According to the present invention, a method of manufacturing a polarizing plate capable of suppressing breakage failure under high temperature and high humidity and suppressing unevenness in luminance when applied to an image display device, a method of manufacturing a liquid crystal display device having the above polarizing plate, and The optical film which can suppress the destructive failure of a polarizing plate under high humidity, and can suppress a brightness nonuniformity when it applies to an image display can be provided.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application (No. 2017-220289) filed on Nov. 15, 2017, the contents of which are incorporated herein by reference.

Claims (5)

A step of forming a coating layer on a temporary support and drying to form a transfer film having an optical film formed on the temporary support;
Attaching a polarizer to the air interface side surface of the optical film in the transfer film;
It is a manufacturing method of a polarizing plate which has a process of exfoliating said temporary support from said transfer film,
The optical film contains 25 to 45% by mass of a copolymer containing a structural unit derived from butadiene based on the total solid content of the optical film,
The optical film contains 0.1 to 10% by mass of a polyester-based additive based on the total solid content of the optical film,
The thickness of the optical film is 4 to 10 μm,
The elongation at break of the optical film is 2.5% or more in an environment of 25 ° C. in a sample with a thickness of 30 μm and a width of 10 mm,
The manufacturing method of the polarizing plate whose arithmetic mean roughness of the surface of the side which forms the said optical film of the said temporary support body is 40 nm or less. The manufacturing method of the polarizing plate of Claim 1 in which the said optical film contains styrene resin. The manufacturing method of a liquid crystal display device which has the process of bonding together the said optical film side of the polarizing plate manufactured by the manufacturing method of Claim 1 or 2 on the liquid crystal cell side. An optical film comprising a copolymer containing a structural unit derived from butadiene, and a polyester-based additive,
The content of the copolymer containing a structural unit derived from butadiene is 25 to 45% by mass with respect to the total solid content of the optical film,
The content of the polyester-based additive is 0.1 to 10% by mass with respect to the total solid content of the optical film,
The thickness of the optical film is 4 to 10 μm,
The optical film whose breaking elongation of the said optical film is 2.5% or more in a 25 degreeC environment in the sample of thickness 30 micrometers and width 10 mm. The optical film according to claim 4, comprising a styrenic resin.