JP6694444B2 - Optical film, polarizing plate, and image display device - Google Patents

Description

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

In recent years, image display devices represented by electroluminescence displays (ELDs) and liquid crystal display devices (LCDs) have been required to be thin and have improved image quality.
In order to achieve such a reduction in thickness, it is necessary to reduce the thickness of the members themselves that form the image display device. Further, in recent years, the uses of the image display device have been diversified including the outdoor use, and the opportunity to use the device in a harsh environment compared to the conventional ones has increased.
On the other hand, regarding the image quality, it is generally known that the image quality may be deteriorated due to the influence of water that has penetrated into the image display device through the member. In a recent environment in which the image display device is used, the image quality is more likely to deteriorate than in the past, and therefore, it is required to enhance the durability of the image display device.

  By the way, as an optical film which is a member of an image display device, a cellulose resin is preferably used from the viewpoint of versatility and processability. Due to the need to enhance the durability described above, modification of the optical film itself is also required, and examples of such an optical film include Patent Documents 1 to 4.

Japanese Unexamined Patent Publication No. 9-197128 Japanese Patent Laid-Open No. 2012-172062 Japanese Patent Laid-Open No. 2015-11059 International Publication No. 2014/119487

When the inventors examined Patent Documents 1 to 4 from the viewpoint of enhancing the durability of the image display device as described above, it was found that there is a problem in durability when used for a long time under high temperature and high humidity conditions. Became.
For example, in the method described in Patent Document 2, the performance of suppressing the permeation of moisture, that is, the low moisture permeability is insufficient, so that the polarizing plate performance deteriorates when used for a long time under high temperature and high humidity conditions, and the image quality deteriorates. Was found to occur. On the other hand, in the case of using the polarizing plate protective film including the transparent base material layer described in Patent Documents 1 and 4 for low moisture permeability and a moisture-proof layer, a transparent base material is used in a peeling test harsher than before. It was found that the moisture-proof layer was peeled off. Further, the liquid crystal display device incorporating the polarizing plate protective film containing the vinyl chloride resin described in Patent Document 3 has a concern about the influence on the environment when it is discarded as it is. Therefore, an object of the present invention is to provide an optical film, a polarizing plate, and an image display device which are excellent in polarizing plate durability and adhesion.

The present invention relates to the following [1] to [7].
[1]
  An optical film having, on a base film, a first cured layer obtained by curing a first curable composition and a second cured layer obtained by curing a second curable composition in this order. 1 curable composition contains a compound having at least an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond, and the second curable composition has at least one molecule of —OH, —NHCOO—, -(C _Two H _Four An optical film comprising a compound having any one of O)-and two or more ethylenically unsaturated double bonds and having an acrylic equivalent of 200 or more.
[2]
  The optical film as described in [1], wherein the aliphatic cyclic hydrocarbon group is a group represented by the following general formula (I).

  In general formula (I), L and L ′ each independently represent a single bond or a divalent or higher valent linking group, and n represents an integer of 1 to 3.
[3]
  The optical film as described in [1] or [2], wherein the base film is a cellulose acylate film.
[4]
  A polarizing plate comprising a polarizer and at least one optical film according to any one of [1] to [3].
[5]
  The polarizing plate according to [4], wherein the second cured layer of the optical film is arranged on the polarizer side.
[6]
  The polarizing plate according to [4] or [5], wherein the second cured layer is in contact with the polarizer via an adhesive layer containing an epoxy material.
[7]
  An image display device comprising a liquid crystal cell and the polarizing plate according to any one of [4] to [6] arranged in at least one of the liquid crystal cells.
  Although the present invention relates to the above [1] to [7], other matters are also described for reference.

  In one aspect of the present invention, the aliphatic cyclic hydrocarbon group is a group represented by the following general formula (I).

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

  In one aspect of the present invention, the base film is a cellulose acylate film.

  In one aspect of the present invention, the compound in the second curable composition of the optical film has two or more ethylenically unsaturated double bonds, and has an acrylic equivalent of 200 or more.

  A further aspect of the present invention relates to a polarizing plate including a polarizer and at least one optical film.

  One embodiment of the present invention is a polarizing plate in which the second cured layer of the optical film is arranged on the polarizer side.

  In one aspect of the present invention, the second cured layer is in contact with the polarizer via an adhesive layer containing an epoxy-based material.

  A further aspect of the present invention relates to an image display device having a polarizing plate.

  According to the present invention, it is possible to provide an optical film, a polarizing plate, and an image display device which are excellent in polarizing plate durability and adhesion.

It is a figure which shows 1 aspect of the laminated constitution of the optical film of this invention. It is a figure which shows 1 aspect of the laminated constitution of the polarizing plate of this invention.

  Hereinafter, the optical film, the polarizing plate and the image display device of the present invention will be described in detail. In addition, in this invention, "-" is used by the meaning including the numerical value described before and after that as a lower limit and an upper limit. Further, in the present invention, "(meth) acrylate" means "acrylate" and "methacrylate".

<< 1. Optical film >>
As shown in FIG. 1, an optical film according to an aspect of the present invention includes a first curable layer 2 obtained by curing a first curable composition on a base film 1, and a second curable composition. An optical film having a cured second layer 3 in this order, wherein the first curable composition contains a compound having at least an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond, An optical system in which the curable composition of No. ₂ contains a compound having at least one of —OH, —NHCOO—, and — (C ₂ H ₄ O) — in one molecule and an ethylenically unsaturated double bond. It is a film.

  In the optical film that is thinner than the conventional optical film, infiltration of water from the outside to the inside of the liquid crystal display device is likely to occur, and particularly under severer use conditions than before, such as high temperature and high humidity conditions, It is considered that the infiltration of water is further promoted. It is considered that the water thus entering the polarizer causes the hydrolysis reaction of the boric acid crosslink and the decomposition of the polyiodide ion and the complex to proceed with time. Furthermore, it is presumed that the diffusion of iodines to the outside of the polarizer progresses, the amount of iodines contained in the polarizer decreases, the polarization performance deteriorates, and the image quality deteriorates.

However, in the study by the present inventors, the polymer described in Patent Document 1 for the purpose of suppressing the infiltration of water into the layer containing cellulose acylate from the viewpoint of easy attachment to the polarizer. It has been found that when the layers are laminated, peeling occurs between the layer containing cellulose acylate and the polymer layer.
Here, the present inventors have found that a first curable layer obtained by curing a first curable composition containing a compound having at least an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond, and at least one molecule A second curable composition containing a compound having at least one of —OH, —NHCOO—, and — (C ₂ H ₄ O) — and an ethylenically unsaturated double bond. It was found that the use of the cured layer of No. 2 improved the adhesion between the optical film and the polarizer.
Furthermore, it was found that the polarizing plate using the optical film of the present invention has excellent polarizing plate durability and can suppress deterioration of image quality even when used for a long time under high temperature and high humidity conditions.

  Hereinafter, the first cured layer, the second cured layer and the base film of the optical film of the present invention will be described in detail.

<1-1: First Hardened Layer>
The first curable layer in the present invention is formed by curing the first curable composition. The first curable composition contains a compound having at least an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond.

[Compound having an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond]
The compound having an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond can function as a binder.

  By using a compound having an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond, the durability of the polarizing plate can be improved. Although details are not clear, by using a compound having an aliphatic cyclic hydrocarbon group in the molecule, it is possible to prevent the incorporation of the molecule from the outside and reduce the iodine diffusion preventing property. Further, by having an ethylenically unsaturated double bond in the molecule, the density of cross-linking points is increased and the diffusion path of water molecules in the iodine diffusion preventing layer is restricted. Increasing the cross-linking point density also has the effect of relatively increasing the density of the aliphatic cyclic hydrocarbon group, making the layer obtained by curing the aliphatic cyclic hydrocarbon-based monomer composition more hydrophobic and adsorbing water molecules. It is thought to prevent and reduce water vapor permeability.

The number of ethylenically unsaturated double bonds contained in the molecule in order to increase the density of cross-linking points is more preferably 2 or more.
The aliphatic cyclic hydrocarbon group is preferably a group derived from an alicyclic compound having 7 or more carbon atoms, more preferably a group derived from an alicyclic compound having 10 or more carbon atoms, and further preferably Is a group derived from an alicyclic compound having 12 or more carbon atoms. The aliphatic cyclic hydrocarbon group is particularly preferably a group derived from a bicyclic, tricyclic or other polycyclic compound. More preferably, the central skeleton of the compound described in the claims of JP-A-2006-215096, the central skeleton of the compound described in JP-A-2001-10999, or the skeleton of an adamantane derivative can be mentioned.

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

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

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

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

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

  In the general formula (IV), L and L ′ each independently represent a single bond or a divalent or higher valent connecting group, and L ″ represents a hydrogen atom, a single bond or a divalent or higher valent connecting group.

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

Examples of the ethylenically unsaturated double bond include polymerizable functional groups such as (meth) acryloyl group, vinyl group, styryl group, and allyl group, and among them, (meth) acryloyl group and -C (O) OCH = CH. ₂ is preferred. More preferably, the following compounds having two or more (meth) acryloyl groups in one molecule can be used.

  The compound having an aliphatic cyclic hydrocarbon group and having two or more ethylenically unsaturated double bonds in the molecule is a compound having the above aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond. It is configured by bonding via a linking group.

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

  Specific preferred examples of the compound having an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond are shown below, but the invention is not limited thereto.

[Compound having ethylenically unsaturated double bond having no aliphatic cyclic hydrocarbon group]
In the aliphatic cyclic hydrocarbon-based monomer composition used in the present invention, a compound having an ethylenically unsaturated double bond that does not have an aliphatic cyclic hydrocarbon group in the molecule can be used together within a range that does not impair the effects of the present invention. ..

  The compound having an ethylenically unsaturated double bond that does not have an aliphatic cyclic hydrocarbon group is preferably a (meth) acrylate compound that does not have an aliphatic cyclic hydrocarbon group, and is a (meth) alkylene glycol. Acrylic acid diesters, polyoxyalkylene glycol (meth) acrylic acid diesters, polyhydric alcohol (meth) acrylic acid diesters, ethylene oxide or propylene oxide adduct (meth) acrylic acid diesters, epoxy (meth) acrylates Examples thereof include urethane (meth) acrylates and polyester (meth) acrylates.

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

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

As the compound having an ethylenically unsaturated double bond having no aliphatic cyclic hydrocarbon group, a compound having a hydrogen-bonding substituent has the following properties: adhesion to a support, low curl, and inclusion of a compound described later. It is preferable from the viewpoint of the fixability of fluorine or silicone compounds. The hydrogen-bonding substituent refers to a substituent in which an atom such as nitrogen, oxygen, sulfur, or halogen and a hydrogen bond are bonded by a covalent bond, and specifically, -OH, -SH, -NH-, -CHO. , -CONH-, -OCONH- and the like, and urethane (meth) acrylates and (meth) acrylates having a hydroxyl group are preferable. A commercially available polyfunctional acrylate having a (meth) acryloyl group can also be used, and NK oligo U4HA manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-TMM-3 manufactured by Shin-Nakamura Chemical Co., Ltd., and KAYARAD manufactured by Nippon Kayaku Co., Ltd. PET-30 etc. can be mentioned.
When the content of a compound having an ethylenically unsaturated double bond that does not have an aliphatic cyclic hydrocarbon group is contained, the content is when the total solid content of the aliphatic cyclic hydrocarbon-based monomer composition is 100% by mass. In addition, it is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, and further preferably 3 to 15% by mass.

[Other Materials Included in First Curable Composition]
The first curable composition used in the present invention further contains a polymerization initiator, an epoxy monomer, a photoacid generator (cationic polymerization initiator), an ultraviolet absorber, and a surface active agent as long as the effects of the present invention are not impaired. Various additives and solvents such as agents, weather resistance improvers, hardness improvers, antiglare imparting agents, slipperiness imparting agents, matting agents and the like can be included.

[Polymerization initiator]
The first curable composition of the present invention preferably contains a polymerization initiator. As the polymerization initiator, a photo radical polymerization initiator is preferable.
As the photo-radical polymerization initiator, acetophenones, benzoins, benzophenones, phosphine oxides, oximes, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, disulfide compounds, lophine dimers, onium Examples thereof include salts, borate salts, active esters, active halogens, inorganic complexes and coumarins. Specific examples, preferred embodiments, commercially available products, etc. of the photopolymerization initiator are described in paragraphs [0133] to [0151] of JP2009-098658A, and the same can be suitably used in the present invention. it can.

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

  Examples of commercially available photocleavable photoradical polymerization initiators include "Irgacure 651", "Irgacure 184", "Irgacure 819", "Irgacure 907" and "Irgacure 1870" (CGI-403 / Irgacure 184 =, manufactured by BASF). 7/3 mixing initiator), "Irgacure 500", "Irgacure 369", "Irgacure 1173", "Irgacure 2959", "Irgacure 4265", "Irgacure 4263", "Irgacure 127", "OXE01", etc .; "Kayakyu DETX-S", "Kayakyu BP-100", "Kayakyu BDMK", "Kayakyu CTX", "Kayakyu BMS", "Kayakyu 2-EAQ", "Kayakyu ABQ", "Kayakyu CPTX" manufactured by Yakuhin Co., Ltd. ", "Cure EPD", "Kayacure ITX", "Kayacure QTX", "Kayacure BTC", "Kayacure MCA", etc .; And the like, and combinations thereof are preferred examples.

  The content of the photopolymerization initiator in the first curable composition used in the present invention is set such that the polymerizable compound contained in the composition is polymerized and the starting point is not excessively increased. Therefore, the total solid content in the composition is preferably 0.5 to 8% by mass, and more preferably 1 to 5% by mass.

〔solvent〕
The first curable composition used in the present invention may contain a solvent. As the solvent, various solvents can be used in consideration of the solubility of the monomer, the drying property during coating, the dispersibility of the translucent particles, and the like. Examples of the organic solvent include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate and carbonic acid. Methyl ethyl, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, Methyl propionate, ethyl propionate, γ-ptyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-meth Ciethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, methyl acetoacetate, etc. 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, tol Examples thereof include ene and xylene, and these can be used alone or in combination of two or more.

  Of the above solvents, it is preferable to use at least one of dimethyl carbonate, methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone (MIBK), acetylacetone, and acetone, and to use methyl acetate, methyl ethyl ketone, and methyl isobutyl ketone (MIBK). It is more preferable to use either one.

  The solvent is preferably used so that the concentration of the solid content of the first curable composition of the present invention is in the range of 20 to 80% by mass, more preferably 30 to 75% by mass, and further preferably 40 to It is 70% by mass.

[Film Thickness of First Cured Layer Formed by Curing First Curable Composition]
The film thickness of the first cured layer of the present invention is preferably 0.5 to 25 μm, more preferably 1 to 20 μm, further preferably 1.5 to 15 μm, and 2 to 10 μm. It is particularly preferable that
The film thickness of the first cured layer can be determined from the difference between the film thicknesses before and after the first cured layer is laminated on the base film.

[Structure of First Cured Layer, Manufacturing Method]
The first cured layer of the present invention may be a single layer or a plurality of layers. The method for laminating the first curable layer is not particularly limited, but the first curable composition may be prepared by co-casting with a base film, or the first curable composition may be the above-mentioned base. It is preferable that the first curable composition is provided on the material film by coating, and it is more preferable that the first curable composition is provided on the substrate film by coating.

The specific method of applying the first curable composition is not particularly limited, but a die coat coating method using a slot die can be preferably used. Further, the transport speed at the time of coating is not particularly limited, but it is preferable to coat at a transport speed of 1 to 100 m / min. The drying after coating is also not particularly limited, and the drying temperature is preferably 25 to 140 ° C. and 30 to 1000 seconds.
When performing curing by UV light, the illuminance is preferably 10~5000mW / cm ^2, more preferably 30~3000mW / cm ^2, more preferably 50~1000mW / cm ^2.
Further, the curing by UV light can be carried out under air as long as there is no problem with stickiness of the film surface after curing, but the oxygen concentration at the time of curing is preferably 10 ppm to 20000 ppm, more preferably 50 ppm to 10000 ppm, More preferably 100 ppm to 5000 ppm.
Curing by UV light can also be performed in two or more stages. Further, the curable composition may be provided and UV-cured, then the second cured layer may be provided, and UV-cured again. In this case, the integrated amount of illuminance is preferably within the above range.

[Water vapor transmission rate of the first cured layer]
The moisture permeability of the optical film is measured based on JIS Z-0208 under the conditions of 40 ° C. and 90% relative humidity. From gas permeation formula of composite film (“Science of barrier properties of packaging materials (packaging basic course 5)” p68-72 Tsutomu Nakagawa, Japan Packaging Association), moisture permeability of steady-state optical film J _f , substrate film Where J _s is the water vapor permeability and J _b is the water vapor permeability of the first cured layer when the optical film is separated into the base film and the first cured layer, the following formula is established.
1 / J _f = 1 / J _s + 1 / J _b (1)
The water vapor transmission rate J _f of the optical film and the water vapor transmission rate J _s of the base film can be directly measured, and the water vapor transmission rate J _b of the first cured layer can be calculated based on the measured values.
In the present invention, the water vapor transmission rate of the first cured layer is preferably 30 to 400 g / m ² / day.

<1-2: Second cured layer>
The second curable layer of the present invention is formed by curing the second curable composition. The second curable composition is a compound having at least one of —OH, —NHCOO—, and — (C ₂ H ₄ O) — in at least one molecule and an ethylenically unsaturated double bond. including. By using such a highly polar compound, the adhesiveness between the second cured layer and the adhesive can be enhanced, and by having an ethylenically unsaturated double bond at the same time, the cured layer can also be cross-linked. The adhesiveness with the cured layer can be improved.

[Compound having one or more of —OH, —NHCOO—, and — (C ₂ H ₄ O) — in one molecule and an ethylenically unsaturated double bond]
As commercially available products, as an —OH-containing compound, “Denacol Acrylate DA-314”, “Denacol Acrylate DA-212”, “Denacol Acrylate DA-911M” from Nagase Chemtex Co., Ltd., NOF Corporation "Blenmer GLM" of -NHCOO-containing compound, "UA-306H" and "UA-306I" of Kyoeisha Chemical Co., Ltd., "U-10HA" and "U-200PA" of Shin Nakamura Chemical Co., Ltd. _{, - (C 2 H 4 O} ) - as containing compound, "Viscoat # 360" of Osaka Organic chemical industry Ltd., Shin-Nakamura chemical industry Co., Ltd. "NK ester a-200", "NK ester a-400" , "NK ester A-600" and the like, but are not limited thereto.
The compound having at least one of —OH, —NHCOO—, and — (C ₂ H ₄ O) — in one molecule and an ethylenically unsaturated double bond is preferably an ethylenically unsaturated double bond. It has two or more bonds and has an acrylic equivalent of 200 or more. More preferably, it has 2 or more and 3 or less ethylenically unsaturated double bonds, and has an acrylic equivalent of 200 or more and 400 or less. By keeping the ethylenically unsaturated double bond and the acrylic equivalent within this range, the crosslink density of the first cured layer and the second cured layer can be increased, and the adhesion between the first cured layer and the second cured layer can be improved. It is possible to improve the sex. Furthermore, the adhesive easily penetrates into the second cured layer, and the adhesiveness between the second cured layer and the adhesive can be improved.
In the present specification, the acrylic equivalent refers to the mass of the polymerizable compound per 1 gram equivalent of (meth) acryloyl group, and the molecular weight of the polymerizable compound is the (meth) acryloyl group per molecule of the polymerizable compound. It is a value [(molecular weight) / (number of (meth) acryloyl groups in one molecule)] divided by the number of.

[Other Materials Included in Second Curable Composition]
Furthermore, the second curable composition is a photoradical polymerization initiator, an epoxy monomer, a photoacid generator (cationic polymerization initiator), a polyester urethane resin, an ultraviolet absorber, a surfactant, a weather resistance improver, and a hardness improver. Various additives such as an agent, an antiglare agent, a slipperiness agent, a matting agent and the like, and a solvent can be included.

[Film Thickness of Second Hardened Layer]
The thickness of the second cured layer of the present invention is preferably 0.05 to 2.5 μm, more preferably 0.1 to 1.0 μm.

<Step of applying the second curable composition>
The second cured layer is preferably formed by a method including a step of applying the second curable composition.
The specific method of the step of applying the second curable composition is the same as the step of applying the first curable composition, and the preferred range is also the same.

<Iodine diffusion prevention layer>
In the optical film of the present invention, the first cured layer and the second cured layer may be collectively referred to as an iodine diffusion preventing layer.
When the compound represented by the above general formula (I) is used as the compound having an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond, the effect can be more exerted.

<1-3. Base film>
[Material of base film]
As a material for forming the base film (support), a polymer having excellent optical performance transparency, mechanical strength, thermal stability and isotropic property is preferable. The term "transparent" as used in the present invention means that the transmittance of visible light is 60% or more, preferably 80% or more, and particularly preferably 90% or more. Examples include polycarbonate-based polymers, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, (meth) acrylic polymers such as polymethylmethacrylate, and styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Be done. Also, polyolefins such as polyethylene and polypropylene, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, sulfone polymers, polyether sulfone polymers Examples thereof include polyether ether ketone-based polymers, polyphenylene sulfide-based polymers, vinylidene chloride-based polymers, vinyl butyral-based polymers, arylate-based polymers, polyoxymethylene-based polymers, epoxy-based polymers, and mixtures of the above polymers. The polymer film of the present invention can also be formed as a cured layer of an acrylic, urethane-based, acrylic urethane-based, epoxy-based, silicone-based, etc. ultraviolet-curable or thermosetting resin.

  As a material for forming the base film, a cellulose-based polymer (particularly preferably cellulose acylate), which has been used as a transparent protective film for a polarizing plate and is typified by triacetyl cellulose, is also preferably used. it can.

[Cellulose acylate]
As the cellulose acylate film, for example, those described in JP-A-2013-228720, paragraphs [0072] to [0075] can be used.

[Other additives]
Additives such as an ultraviolet absorber, a matting agent, a retardation enhancer, a plasticizer, an ultraviolet absorber, a deterioration inhibitor, a release agent, an infrared absorber and a wavelength dispersion adjusting agent can be added to the base film. , They may be solid or oily. That is, its melting point and boiling point are not particularly limited. Furthermore, the addition amount of each material is not particularly limited as long as the function is exhibited. Further, when the optical film is formed of multiple layers, the type and amount of the additive in each layer may be different.

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

When these additives are added to the substrate film, the total amount of the additives is preferably 50% by mass or less, and more preferably 30% by mass or less, based on the substrate film.
By these additives, the brittleness of the film is improved, and the folding endurance test of the film (e.g., evaluation of cracking at 180 degree bending) is significantly improved.
Further, in order to achieve low haze, it is preferable that the refractive index of the above-mentioned additive has substantially the same refractive index as that of the base film, and the refractive index difference is preferably 0.5 or less, more preferably 0.3 or less. preferable.

[Characteristics of base film]
(Base film thickness)
The thickness of the base film is preferably 5 to 100 μm, more preferably 10 to 80 μm, particularly preferably 15 to 70 μm, and particularly preferably 20 to 60 μm.

(surface treatment)
The substrate film may be subjected to a surface treatment, if necessary, to improve the adhesion between the substrate film and the first cured layer or other layers (for example, a polarizer, an undercoat layer and a back layer). You can For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs under a low pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferable. The plasma-excitable gas refers to a gas that is plasma-excited under the above-mentioned conditions, and examples thereof include CFCs such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, and tetrafluoromethane, and a mixture thereof. Be done. Details of these are described in detail in pages 30 to 32 of the Technical Bulletin of the Institute of Invention, Kokai Giho (Kogi No. 2001-1745, published by Mar. 15, 2001, pages of invention), and are preferably used in the present invention. be able to.

<1-4. Functional layer>
If desired, the optical film of the present invention may be provided with a functional layer according to the purpose. Examples of the functional layer include a hard coat layer, an antireflection layer, a light scattering layer, an antifouling layer, an antistatic layer, and the like, and one layer may also have a plurality of functions.
From the viewpoint of enhancing the effect of the present invention, these layers are preferably provided on the surface of the base film opposite to the cured layer of the aliphatic cyclic hydrocarbon monomer composition.

<< 2. Polarizer >>
The polarizing plate of the present invention includes a polarizer and at least one optical film of the present invention.
The polarizing plate of the present invention comprises a polarizer and at least one optical film of the present invention disposed on only one side of the polarizer. Generally, a polarizing plate in which both sides of a polarizer are sandwiched between polarizing plate protective films to protect both sides is widely used.
When the polarizing plate has protective films on both sides of the polarizer, it may have a polarizing plate protective film different from the optical film of the present invention on the surface opposite to the surface having the optical film of the present invention. It may have a known polarizing plate protective film.
For example, as the polarizing plate protective film different from the optical film of the present invention, the additive or the kind thereof contained, the content different, the characteristic different, the presence or absence of the functional layer or the different functional layer, etc. ..

<2-1: Polarizer>
The polarizer is composed of at least a dichroic dye and a resin.

[resin]
A polyvinyl alcohol-based resin is preferably used for the polarizer of the present invention. The polarizer in the present invention contains a polyvinyl alcohol resin as a main component, and usually accounts for 80% by mass or more of the polarizer. Polyvinyl alcohol is usually saponified polyvinyl acetate, but may contain a component copolymerizable with vinyl acetate, such as unsaturated carboxylic acid, unsaturated sulfonic acid, olefins, vinyl ethers. Absent. Further, a modified polyvinyl alcohol-based resin containing an acetoacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group or the like can also be used.

  The saponification degree of the polyvinyl alcohol-based resin is not particularly limited, but is preferably 80 to 100 mol% and particularly preferably 90 to 100 mol% from the viewpoint of solubility and the like. The degree of polymerization of the polyvinyl alcohol-based resin is not particularly limited, but it is preferably 1,000 to 10,000, particularly preferably 1,500 to 5,000.

The elastic modulus of the polyvinyl alcohol-based resin film before stretching is preferably 0.1 MPa or more and 500 MPa or less, more preferably 1 MPa or more and 100 MPa or less when expressed in Young's modulus.
Within such a range, a polyvinyl alcohol-based resin film having an excellent effect of suppressing the generation of wrinkles after stretching and having sufficient strength can be manufactured.

  The thickness of the polyvinyl alcohol-based resin film before stretching is not particularly limited, but is preferably 1 μm to 1 mm, particularly preferably 20 to 200 μm, from the viewpoint of stability of film retention and homogeneity of stretching. Further, the film thickness of the polyvinyl alcohol-based resin film after stretching is preferably 2 to 100 μm, and 7 to 25 μm is preferable for improving light leakage. This thickness defines the thickness of the polarizer film.

[Dichroic dye]
The polarizer of the present invention contains a dichroic dye. Here, the dichroic dye means a dye having different absorbance depending on the direction, and includes iodine ions, diazo dyes, quinone dyes, and other known dichroic dyes. As the dichroic dye, a higher iodine ion such as I ₃ ⁻ or I ₅ ⁻ or a dichroic dye can be preferably used.
In the present invention, higher iodine ions are particularly preferably used. Higher order iodine ions are described in “Application of Polarizing Plates” edited by Ryo Nagata, CMC Publishing and Industrial Materials, Volume 28, No. 7, p. 39-p. As described in No. 45, polyvinyl alcohol can be produced by immersing polyvinyl alcohol in a solution in which iodine is dissolved in an aqueous potassium iodide solution and / or an aqueous boric acid solution and being adsorbed and oriented in the polyvinyl alcohol.

  The content of the dichroic dye is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 20 parts by mass, and still more preferably 1.0 to 5.0 parts by mass with respect to the polyvinyl alcohol resin. ..

  In addition to the polyvinyl alcohol resin and the dichroic dye, the polarizer of the present invention may optionally contain a plasticizer and a surfactant.

<2-2: Method for manufacturing polarizer>
As the method for producing the polarizer of the present invention, for example, it is preferable to form a polyvinyl alcohol-based resin into a film and then introduce iodine to form the polarizer. The production of a polyvinyl alcohol-based resin film is carried out by the method described in paragraph Nos. 0213 to 0237 of JP 2007-86748 A, JP 3342516 JP, JP 09-328593 A, JP 2001-302817 A, It can be performed with reference to, for example, JP-A-2002-144401.

  In the present invention, particularly, a step of forming a polyvinyl alcohol-based resin solution having a polyvinyl alcohol-based resin into a film, a step of stretching a polyvinyl alcohol-based resin film, and a polyvinyl alcohol-based resin film after stretching with a dichroic dye. It is preferable to include a step of dyeing and a step of crosslinking the polyvinyl alcohol-based resin film after dyeing with boric acid.

<2-3: Shape / configuration>
The shape of the polarizing plate of the present invention is not only the polarizing plate in the form of a film piece cut into a size that can be incorporated into a display device as it is, but also produced in a continuous shape by continuous production and wound into a roll. A polarizing plate having such a form (for example, a roll length of 2500 m or more or a roll length of 3900 m or more) is also included. The width of the polarizing plate is preferably 1470 mm or more for use in a large-screen liquid crystal display device.

The polarizing plate of the present invention is composed of a polarizer and at least one sheet of the optical film of the present invention. Further, a protective film (not the optical film of the present invention) is provided on one surface of the polarizing plate and the other surface thereof. It is also preferable that a separate film is laminated.
The protect film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is attached for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the side where the polarizing plate is attached to the liquid crystal plate. Further, the separate film is used for the purpose of covering the adhesive layer that is stuck to the liquid crystal plate, and is used on the surface side where the polarizing plate is stuck to the liquid crystal plate.

<2-4: Method of Laminating Polarizer and Optical Film>
A method of laminating the polarizer and the optical film will be described with reference to FIG.
The polarizing plate of the present invention has at least one optical film of the present invention (base film 1, first cured layer 2, and second cured layer) on at least one surface of the polarizer 5 obtained above. It can be manufactured by laminating optical films composed of the layer 3. When laminating, it is preferable to interpose the adhesive layer 4.
The polarizing plate of the present invention is preferably prepared by a method in which the surface of an optical film is subjected to corona treatment, an adhesive composition is applied, the adhesive composition is attached to a polarizer, and ultraviolet rays are applied to cure the resin.
Examples of the adhesive used in the adhesive composition for the adhesive layer for laminating the processed surface of the optical film and the polarizer include, for example, JP2012-140610A, JP2012-208250A, and JP2012-208250A. Known adhesives described in JP-A-2015-203733 and the like can be mentioned.

Among these, it is preferable to include an epoxy material, and it is particularly preferable that the epoxy material be an epoxy compound having an alicyclic epoxy group or a glycidyl compound. Specific examples include the following.
Celoxide 8000, Celoxide 2021P, Cyclomer M100, EHPE3150 (all manufactured by Daicel Co., Ltd.), TTA20, TTA22, TTA27 (manufactured by Tetrachem), Licaredin DME-100, Licaredin HBE-100, (Nippon Rika Kasei Co., Ltd.). And the like, and Celoxide 8000, Celoxide 2021P, TTA22 and Lycaredin DME-100 are preferable.

[Other materials]
The adhesive composition containing the epoxy material preferably contains a cationic photopolymerization initiator. Preferred examples of the photocationic polymerization initiator include compounds that generate a cation species or a Lewis acid upon irradiation with an active energy ray, for example, an onium salt such as an aromatic diazonium salt, an aromatic iodonium salt or an aromatic sulfonium salt, and iron. An allene complex and the like.
Further, the adhesive containing the epoxy material may contain other additives, and examples thereof include an oxetane compound, an acrylic monomer, a photoradical polymerization initiator, a sensitizer, a surfactant, and a solvent.

  The optical film of the present invention is preferably attached so that the second cured layer is on the side closer to the polarizer. With the above-mentioned configuration, it is possible to effectively suppress the diffusion of iodines to the outside of the polarizer, and it becomes difficult for polarization performance to deteriorate when stored for a long period under a high temperature and high humidity environment, which is preferable.

<2-5: Functionalization of polarizing plate>
The polarizing plate of the present invention is a functionalized polarized light compounded with a polarizing plate protective film having an antireflection film for improving the visibility of a display, a brightness enhancement film, and a functional layer such as a forward scattering layer and an antiglare (antiglare) layer. It is also preferably used as a plate. The antireflection film for functionalization, the brightness enhancement film, the other functional optical film, the forward scattering layer, the anti-glare layer are described in paragraph Nos. 0257 to 0276 of JP2007-86748A, and these descriptions are described. A functionalized polarizing plate can be produced.

<2-6: Performance of polarizing plate>
[Polarization degree]
The polarization degree of the polarizing plate of the present invention is preferably 95% or more, more preferably 98% or more, and most preferably 99.5% or more.

  In the present invention, the polarization degree of the polarizing plate is determined by the following formula from the orthogonal transmittance and the parallel transmittance measured at a wavelength of 380 nm to 700 nm using an automatic polarizing film measuring device VAP-7070 manufactured by JASCO Corporation. Can be calculated, and the weighted average of the light source (auxiliary illuminant C) and CIE visibility (Y) can be calculated.

Polarization degree (%)
= {(Parallel transmittance-orthogonal transmittance) / (parallel transmittance + orthogonal transmittance)} ^1/2 × 100

[Polarizing plate durability]
The polarizing plate of the present invention is excellent in the durability of the polarizing plate under the conditions of wet heat aging. Therefore, the amount of change in the polarization degree before and after the polarizing plate durability test is small.
The polarizing plate of the present invention measures the orthogonal transmittance and parallel transmittance using an automatic polarizing film measuring device VAP-7070 manufactured by JASCO Corporation, and calculates the degree of polarization by the above formula, particularly at 85 ° C, relative. The amount of change in polarization degree when stored for 720 hours in an environment of 85% humidity is preferably less than 1%.

  Two samples (5 cm × 5 cm) in which the polarizing plate of the present invention is attached onto glass via an adhesive are prepared. At this time, the polarizing plate protective film of the present invention is attached so that it is on the glass side. The orthogonal transmittance measurement is performed by setting the glass side of this sample toward the light source. Two samples are measured, and the average value thereof is taken as the orthogonal transmittance and the parallel transmittance. Specifically, it is as described in the examples.

[Other characteristics]
Other preferable optical properties and the like of the polarizing plate of the present invention are described in paragraph Nos. 0238 to 0255 of JP2007-086748A, and it is preferable to satisfy these properties.

<< 3. Image display device >>
Examples of the image display device according to one aspect of the present invention include a liquid crystal display device and an organic electroluminescence display device for antireflection use.
Taking a liquid crystal display device as an example, the liquid crystal display device of the present invention includes at least a liquid crystal cell and the polarizing plate of the present invention disposed in at least one of the liquid crystal cells. The liquid crystal display device has a configuration in which a liquid crystal cell is arranged between two polarizing plates like the first polarizing plate and the second polarizing plate. The drive mode of the liquid crystal cell is not particularly limited, but each drive mode such as TN, OCB, VA, and IPS is generally used. Furthermore, it is preferable to use an optically anisotropic layer that performs optical compensation according to the driving mode of the liquid crystal cell, and it is arranged between the liquid crystal cell and the polarizing plate. The polarizing plate protective film may have the function of the optically anisotropic layer.

  The features of the present invention will be described more specifically below with reference to Examples and Comparative Examples. The materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the following specific examples.

[Production of Reference Example 101]
<Preparation of cellulose acylate>
A cellulose acylate having an acetyl substitution degree of 2.87 was prepared. In this, sulfuric acid (7.8 parts by mass relative to 100 parts by mass of cellulose) was added as a catalyst, a carboxylic acid as a raw material of an acyl substituent was added, and an acylation reaction was carried out at 40 ° C. After the acylation, aging was carried out at 40 ° C. Furthermore, the low molecular weight components of this cellulose acylate were removed by washing with acetone.

<Preparation of Dope 101 Liquid for Air Side Surface Layer>
(Preparation of Cellulose Acylate Solution 1)
The following composition was put into a mixing tank and stirred to dissolve each component, thereby preparing a cellulose acylate solution 1.
――――――――――――――――――――――――――――――――
Composition of Cellulose Acylate Solution 1 ――――――――――――――――――――――――――――――――
Cellulose acetate with acetyl substitution degree of 2.87 and polymerization degree of 370
100.0 parts by mass Sucrose benzoate (benzoyl substitution degree 5.5)
6.0 parts by mass Sigma-Aldrich sucrose acetate isobutyrate
4.0 parts by weight Methylene chloride (first solvent) 353.9 parts by weight Methanol (second solvent) 89.6 parts by weight n-butanol (third solvent) 4.5 parts by weight ――――――――― ―――――――――――――――――――――――

(Preparation of Matting Agent Solution 2)
The following composition was put into a disperser and stirred to dissolve each component, thereby preparing a matting agent solution 2.
――――――――――――――――――――――――――――――――
Composition of Matting Agent Solution 2 ――――――――――――――――――――――――――――――――
Silica particles having an average particle size of 20 nm (AEROSIL R972,
Nippon Aerosil Co., Ltd. 2.0 parts by mass Methylene chloride (first solvent) 69.3 parts by mass Methanol (second solvent) 17.5 parts by mass n-butanol (third solvent) 0.9 parts by mass The above cellulose Acylate solution 1 0.9 parts by mass ――――――――――――――――――――――――――――――――

  1.3 parts by mass of the matting agent solution 2 and 98.7 parts by mass of the cellulose acylate solution 1 were added and mixed using an in-line mixer to prepare an air-side surface layer dope 101 liquid.

<Preparation of base layer dope 102>
(Preparation of Cellulose Acylate Solution 3)
The following composition was put into a mixing tank and stirred to dissolve the respective components to prepare a base layer dope 102.
――――――――――――――――――――――――――――――――
Composition of base layer dope 102 (cellulose acylate solution 3) ――――――――――――――――――――――――――――――――
Cellulose acetate with acetyl substitution degree of 2.87 and polymerization degree of 370
100.0 parts by mass Sucrose benzoate (benzoyl substitution degree 5.5)
6.0 parts by mass Sigma-Aldrich sucrose acetate isobutyrate
4.0 parts by mass UV absorber C 2.0 parts by mass Methylene chloride (first solvent) 297.7 parts by mass Methanol (second solvent) 75.4 parts by mass n-butanol (third solvent) 3.8 parts by mass Department ――――――――――――――――――――――――――――――――
UV absorber C

<Preparation of Dope 103 Solution for Surface Layer on Support Side>
1.3 parts by mass of the matting agent solution 2 and 99.3 parts by mass of the cellulose acylate solution 1 prepared in the dope 101 solution for the surface layer on the air layer side were mixed using an in-line mixer, and the dope 103 for the surface layer on the support side was mixed. A liquid was prepared.

<Base film formation>
(Casting)
Using a drum casting device, the dope prepared above (dope for base layer) and the dope for surface layer on both sides of the dope are simultaneously applied to a stainless casting support (support temperature -9 ° C) from a casting port. Casted on. The residual solvent amount in the dope of each layer was peeled off in a state of about 70% by mass, both ends in the width direction of the film were fixed with pin tenters, and the residual solvent amount of 3 to 5% by mass was 1.28 in the lateral direction. It was dried while being double stretched. After that, the cellulose acylate film of Reference Example 101 was obtained by transporting it between the rolls of the heat treatment apparatus and further drying. The thickness of the obtained cellulose acylate film as the substrate film was 60 μm (air side surface layer 3 μm, base layer 54 μm, support side surface layer 3 μm), and width was 1480 mm.

[Production of Example 101]
(1) Optical film having first cured layer and second cured layer <Preparation of first curable composition (A-1)>
The first curable composition A-1 was prepared with the composition shown below, and filtered by a polypropylene filter having a pore size of 30 μm to prepare.

――――――――――――――――――――――――――――――――
Composition of the first curable composition A-1 ――――――――――――――――――――――――――――――――
Compounds having an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond:
A-DCP [manufactured by Shin-Nakamura Chemical Co., Ltd.] 100.7 parts by mass Irgacure 127 [manufactured by BASF] 2.1 parts by mass Surfactant A 0.02 parts by mass Methyl ethyl ketone 29.2 parts by mass Methyl isobutyl ketone 19.4 Parts by mass Methyl acetate 48.6 parts by mass ――――――――――――――――――――――――――――――――

  The surfactant A is the following compound (the ratio of repeating units is a molar ratio).

<Preparation of Second Curable Composition (B-1)>
A second curable composition B-1 was prepared with the composition shown below and was filtered through a polypropylene filter having a pore size of 30 μm to adjust.

――――――――――――――――――――――――――――――――
Composition of second curable composition B-1 ――――――――――――――――――――――――――――――――
NK Ester A-200 [Shin-Nakamura Chemical Co., Ltd.]
3.4 parts by mass Irgacure 127 [manufactured by BASF Corporation] 0.1 parts by mass Methyl ethyl ketone 29.0 parts by mass Methyl isobutyl ketone 67.5 parts by mass ―――――――――――――――――― ――――――――――――――――

<Formation of first cured layer>
The first curable composition (A-1) was applied to the surface of the substrate film on the side of the casting support described in Reference Example 101 by the microgravure coating method at a conveying speed of 30 m / min. After drying at 60 ° C. for 120 seconds, further under nitrogen purging, an oxygen concentration of about 100 ppm, a substrate film temperature of 25 ° C., and a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) were used. The coating layer was cured by irradiating with ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 100 mJ / cm ² to form a first cured layer having a thickness of 5 μm.

(Oxygen concentration)
Regarding the oxygen concentration, the concentration inside the exposure machine was measured by an oxygen concentration meter OX-102 (manufactured by Yokogawa Electric Corporation).

<Formation of second hardened layer>
The second curable composition (B-1) is applied to the film provided with the first curable layer in contact with the first curable layer by a microgravure coating method under the condition of a transport speed of 30 m / min, After drying at 60 ° C. for 120 seconds, under a nitrogen purge, the oxygen concentration was set to about 100 ppm, the temperature of the substrate film was set to 25 ° C., and an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm was used to measure the illuminance. The second cured layer having a thickness of 0.1 μm was formed by irradiating with ultraviolet rays of 400 mW / cm ² and an irradiation amount of 300 mJ / cm ² to cure. The obtained optical film was used as the optical film of Example 101.

(2) Preparation of polarizing plate <Preparation of composition C-1 for adhesive layer>
Each component was mixed with the composition shown below and stirred at 50 ° C. for 1 hour to obtain an adhesive layer composition C-1.
――――――――――――――――――――――――――――――――
Composition of adhesive layer composition C-1 ――――――――――――――――――――――――――――――――
Celoxide 2021P [manufactured by Daicel Co., Ltd.] 25.0 parts by mass Aron Oxetane OXT-221 [manufactured by Toagosei Co., Ltd.] 50.0 parts by mass Rikaresin DME-100 [manufactured by Shin Nippon Rika Co., Ltd.] 25.0 parts by mass Photo-cationic polymerization initiator: CPI-100P [manufactured by San-Apro]
5.0 parts by mass ――――――――――――――――――――――――――――――――

<Production of polarizer>
A polyvinyl alcohol film having an average degree of polymerization of 2,400, a degree of saponification of 99.9 mol% and a thickness of 75 μm was dipped in warm water at 30 ° C. for 60 seconds to be swollen. Then, while dyeing for 1 minute in an iodine solution of 0.3% by weight (weight ratio: iodine / potassium iodide = 0.5 / 8) at 30 ° C., stretching was performed up to 3.5 times. Then, while being immersed in a 4% by weight boric acid aqueous solution at 65 ° C. for 0.5 minutes, it was stretched to a total stretching ratio of 6 times. After stretching, it was dried in an oven at 70 ° C. for 3 minutes to obtain a polarizer having a thickness of 26 μm. The water content of the polarizer was 13.5% by weight.

<Laminating>
Corona treatment was applied to the second cured layer side of the optical film produced in Example 101 (9.4 kJ / m ² ). On the surface of the second cured layer subjected to corona treatment, the composition C-1 for adhesive layer prepared above was prepared by MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, number of gravure rolls: 1000 pieces / INCH, rotation speed 140% / line speed) was used to obtain a thickness of 0.5 μm.
Separately, a cycloolefin-based film (Arton RX4500 manufactured by JSR Co.) having a thickness of 40 μm was also subjected to corona treatment, and then adhered to the surface of the cycloolefin-based film subjected to corona treatment in the same manner as above. The agent layer composition C-1 was applied so as to have a thickness of 0.5 μm.
Subsequently, the surface coated with the adhesive layer composition C-1 was attached to one surface of the polarizer. Then, from both surfaces of the laminated film (optical film of Example 101 / polarizer / cycloolefin film composition), both film surfaces were heated to 50 ° C. using an IR heater, and from both surfaces. The composition C-1 for adhesive layers was cured by irradiating the active energy rays shown below. Then, it was dried with hot air at 70 ° C. for 3 minutes to obtain a polarizing plate 101.

(Active energy ray)
As an active energy ray, an ultraviolet (gallium-encapsulated metal halide lamp) irradiation device: Fusion UV Systems, Inc. Light HAMMER10 bulb: V bulb peak illuminance: 1600 mW / cm ² , integrated irradiation amount of 1000 mJ / cm ² (wavelength 380 to 440 nm) was used. .. Note that the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell.

[Production of Examples 102 to 113 and Comparative Examples 114 and 115]
Using the second curable compositions B-2 to B-11 having the compositions shown in Table 1 in the same manner as in Example 101, the film thickness, irradiation dose, oxygen concentration, and active energy ray curing shown in Table 1 were performed. Optical films of Examples 102 to 113 and Comparative Examples 114 and 115 were produced using the mold adhesive composition. Further, the polarizing plates of Examples 102 to 113 and Comparative Examples 114 and 115 were obtained in the same manner as the polarizing plate 101 manufactured in Example 101. The unit of the content of each component in Table 1 is "parts by mass".

Cellulose acetate: FRM (acetyl substitution degree: 2.79, Mn: 66000, Mw: 186000) [manufactured by Daicel Chemical Industries, Ltd.]
-A-200: NK ester A-200 (polyethylene glycol # 200 diacrylate) [manufactured by Shin-Nakamura Chemical Co., Ltd.]
-A-400: NK ester A-400 (polyethylene glycol # 400 diacrylate) [manufactured by Shin-Nakamura Chemical Co., Ltd.]
-A-600: NK ester A-600 (polyethylene glycol # 600 diacrylate) [manufactured by Shin-Nakamura Chemical Co., Ltd.]
DA-314: Epoxy acrylate having the following structure [manufactured by Nagase Chemtex Co., Ltd.]

  DA-911M: epoxy acrylate having the following structure [manufactured by Nagase Chemtex Co., Ltd.]

-UA-306H: pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer [manufactured by Kyoeisha Chemical Co., Ltd.]
A-DPH: dipentaerythritol hexaacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.]
-A-DOD-N: 1,10-decanediol diacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.]
MEK-AC-4130Y: Organosilica sol having a particle size of 40 to 50 nm (methyl ethyl ketone dispersion having a solid content of 30% by mass) [manufactured by Nissan Chemical Industries, Ltd.]
-MEK: Methyl ethyl ketone-MIBK: Methyl isobutyl ketone-Surfactant B: The following compounds (the ratio of repeating units is a molar ratio)

Preparation of Adhesive Layer Composition C-2 ――――――――――――――――――――――――――――――――
Composition of adhesive layer composition C-2 ――――――――――――――――――――――――――――――――
Celoxide 2021P [manufactured by Daicel Corporation] 59.0 parts by mass Aron Oxetane OXT-221 [manufactured by Toagosei Co., Ltd.] 5.0 parts by mass Light Acrylate 1,6HX-A [manufactured by Kyoeisha Chemical Co., Ltd.]
30.0 parts by mass Photocationic polymerization initiator: CPI-100P [manufactured by San-Apro]
5.0 parts by mass Photo-radical polymerization initiator: Irgacure 184 [manufactured by BASF] 1.0 parts by mass ―――――――――――――――――――――――――――― ----

[Evaluation]
<Peeling force evaluation>
Each of the polarizing plates of each of the examples and comparative examples prepared above was attached to a glass plate via an adhesive so that the optical film side of the present invention of each polarizing plate faces the glass plate side. The size of each polarizing plate is 2. Vcm × length 15 cm, and the length of the bonded portion was 7 cm.
At the interface between the optical film attached to glass and the polarizer, a peeling trigger (width: 25 mm, length: 10 mm) was created so as to be parallel to the direction of the interface. Then, the member on the side of the polarizer is oriented in a 90 ° direction so that the optical film attached to the glass and the member on the side of the polarizer (for example, in the case of the polarizing plate 101, the laminated polarizer and cycloolefin film) are peeled off ( By pulling the polarizing plate in the vertical direction when it was placed on a horizontal desk), the interfacial peeling was promoted, and only the end portion of the film was peeled off. The load at this time was measured, and this value was used as the interlayer peeling force (N / 25 mm). Tensilon (RTG-1310, manufactured by A & D Corporation) was used for peeling, and the peeling speed was 300 mm / min. Evaluation was made according to the following criteria, and the results are shown in Table 2.
A: When the interlayer peeling force exceeds 3.0 N / 25 mm B: When the interlayer peeling force is 1.5 to 3 N / 25 mm C: When the interlayer peeling force is less than 1.5 N / 25 mm

(Polarizing plate durability)
With respect to the polarizing plates of Examples and Comparative Examples produced above, the degree of polarization was measured to evaluate the durability of the polarizing plates.
After that, the polarization degree was measured by the same method even after storage for 720 hours in an environment of 85 ° C. and relative humidity of 85%. The degree of polarization before and after aging was determined and evaluated according to the following criteria, and the results are shown in Table 2 below as the durability of the polarizing plate.
A: Polarization degree change amount is less than 0.1% B: Polarization degree change amount is 0.1% or more and less than 1% C: Polarization degree change amount is 1 or more and less than 5% D: Polarization degree change amount is 5% or more

  In Comparative Examples 114 and 115, the polarizing plate and the optical film were partly peeled off during the evaluation of the polarizing plate durability, and a portion having a large change in the degree of polarization and a portion having a small change in the degree of polarization were mixed. The part D was mixed.

From the results of Table 2, the polarizing plates of Examples 101 to 113 using the optical film of the present invention have a large delamination force between the optical film and the polarizer, as compared with the polarizing plates of Comparative Examples 114 and 115, and Also, it does not peel off during durability evaluation, and has excellent adhesion. Further, even if stored in a high temperature and high humidity environment, the change in the degree of polarization is small, and the durability of the polarizing plate under the conditions of heat and humidity is excellent.
The examples 101 and 104 to 106 are to be read as the reference examples 101 and 104 to 106, respectively.

  According to the present invention, it is possible to provide an optical film, a polarizing plate, and an image display device which are excellent in polarizing plate durability and adhesion.

Although the present invention has been described in detail and with reference to particular 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 the Japanese patent application filed on December 14, 2015 (Japanese Patent Application No. 2015-243621) and the Japanese patent application filed on December 9, 2016 (Japanese Patent Application No. 2016-239767), the contents of which are as follows. Incorporated here by reference.

1 Base Film 2 First Cured Layer 3 Second Cured Layer 4 Adhesive Layer 5 Polarizer

Claims (7)

An optical film having, on a base film, a first cured layer obtained by curing a first curable composition and a second cured layer obtained by curing a second curable composition in this order. 1 curable composition contains a compound having at least an aliphatic cyclic hydrocarbon group and an ethylenically unsaturated double bond, the second curable composition at least in one molecule -OH, -NHCOO-, _{- (C 2 H 4 O)} - possess either one or more and two or more ethylenically unsaturated double bonds, and a comprising the acrylic equivalent is 200 or more of compound Optical film to do. The optical film according to claim 1, wherein the aliphatic cyclic hydrocarbon group is a group represented by the following general formula (I).

In formula (I), L and L ′ each independently represent a single bond or a divalent or higher valent linking group, and n represents an integer of 1 to 3.   The optical film according to claim 1, wherein the base film is a cellulose acylate film. A polarizing plate comprising a polarizer and at least one optical film according to any one of claims 1 to 3 . The polarizing plate according to claim 4 , wherein the second cured layer of the optical film is arranged on the polarizer side. The polarizing plate according to claim 4 or 5 , wherein the second cured layer is in contact with the polarizer via an adhesive layer containing an epoxy-based material. An image display device comprising: a liquid crystal cell; and the polarizing plate according to any one of claims 4 to 6 disposed in at least one of the liquid crystal cells.

Images