TWI556001B - An optical film, a polarizing plate, and an image display device - Google Patents

Description

Optical film, polarizing plate and image display device

The present invention relates to an optical film having a hardened layer on at least one side of a substrate, a polarizing plate having the optical film, and an image display device having the polarizing plate.

An optical film such as a polarizing plate protective film is generally disposed on the surface of a polarizing plate used for an image display device such as a liquid crystal display (LCD). The polarizing plate protective film is formed, for example, on a substrate made of a cellulose ester film to form a hardened layer. The hardened layer is formed by coating a hard coating material on a substrate and hardening it by irradiation with an active energy ray.

In recent years, liquid crystal display devices such as tablet computers and smart phones have increased in outdoor users. Therefore, not only the liquid crystal display device itself is required to have high durability, but also a structural member (for example, a polarizing plate) of the liquid crystal display device is required to have high durability. However, in a high-temperature and high-humidity environment, moisture easily passes through the polarizing plate protective film, and the polarizing performance of the polarizing mirror is lowered due to the influence of the moisture, and various reviews have been conducted in recent years. For example, in Patent Documents 1 and 2, the cured layer of the optical film is formed of a resin having a specific structure, and the moisture permeability is lowered to improve the durability of the film.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2006-83225 (refer to claim 1, paragraph [0005], [0007], [0013], etc.)

[Patent Document 2] Japanese Laid-Open Patent Publication No. 2014-95890 (refer to claim 1, paragraph [0006], [0007], [0031], etc.)

However, the optical films of Patent Documents 1 and 2 are under the harsh and durable conditions required for higher temperature and high humidity in recent years (for example, in an environment of 80 ° C and a relative humidity of 85% (hereinafter referred to as RH)] Not having a sufficiently low moisture permeability, the protective performance of the polarizer is insufficient, and further improvement of the optical film is required.

In addition, when the optical film is used as the polarizing plate protective film of the image display device in the hardened layer, the visibility of the image display device is deteriorated (for example, black). Unevenness occurs when displayed.)

Therefore, it is desired to realize an optical film which is low in moisture permeability in a high-temperature and high-humidity environment and which suppresses coating unevenness of the hardened layer and which can suppress deterioration of visibility in the image display device.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an image display device capable of suppressing coating unevenness of a hardened layer even under a severe environment of higher temperature and high humidity and having a sufficiently low moisture permeability. An optical film having poor visibility, a polarizing plate having the optical film, and an image display device having the polarizing plate.

The inventors of the present invention have found that the above problems can be solved by forming a hardened layer having the following structure on at least one side of a substrate, and the present invention has been achieved. That is, the above object of the present invention is achieved by the following constitution.

An optical film according to one aspect of the present invention is an optical film having a hardened layer on at least one side of a substrate, the hardened layer comprising an active energy ray-curable resin having an alicyclic structure, and a SP having a solubility parameter a cyclic organic compound having an aromatic ring structure or a polar substituent in an alicyclic structure, and having a value of 17.0 to 21.0 [(J/cm ³ ) ^1/2 ]; and the cyclic organic compound is ethylene A polymer of a monounsaturated monomer.

According to the above configuration, it is possible to realize an optical film having sufficient low moisture permeability even in a severe environment of higher temperature and high humidity. In addition, since the coating unevenness of the hardened layer can be suppressed in the optical film, when the optical film is applied to the polarizing plate of the image display device, the visibility of the image display device can be suppressed from deteriorating.

1‧‧‧Image display device

4‧‧‧ LCD cell (display cell)

5‧‧‧Polar plate

11‧‧‧ polarizer

12‧‧‧ Film substrate (substrate)

13‧‧‧ hardened layer

15‧‧‧Optical film

Fig. 1 is a cross-sectional view showing a schematic configuration of an image display device according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing the configuration of an optical film to which a polarizing plate of the image display device is applied.

[Formation of the Invention]

In one embodiment of the present invention, the following description will be made based on the drawings. In other words, in the present specification, when the numerical range is described as A to B, it is considered that the numerical value range includes the lower limit A and the upper limit B. Further, the present invention is not limited by the following contents.

The inventors of the present invention have a low degree of moisture permeability in the films of Patent Documents 1 and 2 which are not sufficiently high temperature and high humidity required in recent years (for example, 80 ° C 85% RH), and the protective properties of the polarizer. Insufficient problem, in order to further improve the optical film, the optical film having the following constitution was reviewed. That is, an optical film having a hardened layer in which a low molecular weight cyclic organic compound is added to an active energy ray-curable resin having an alicyclic structure on a substrate. The above cyclic organic compound has an aromatic ring structure or a polar substituent in the alicyclic structure.

By adding the above-mentioned low molecular weight cyclic organic compound to the above resin, the above-mentioned cyclic organic compound can be used to fill the voids of the above resin, thereby suppressing the diffusion of water molecules in the hardened layer, thereby being durable and durable even at higher temperatures and high humidity. Under conditions, low moisture permeability can also be achieved. However, it is known that even if the optical film is low in moisture permeability, when the above-mentioned optical film is used on the polarizing plate of the image display device, a new problem that the visibility of the image display device is deteriorated occurs.

In order to solve such a problem that the visibility is deteriorated, the inventors of the present invention have found that an optical film can be obtained by adding a cyclic organic compound having a specific structure to an active energy ray-curable resin having an alicyclic structure. The low moisture permeability reduces the visibility of the image display device. Here, the cyclic organic compound of the polymer having the specific structure described above has a solubility parameter having an SP value of 17.0 to 21.0 [(J/cm ³ ) ^1/2 ], and has an aromatic ring structure or an alicyclic structure. A polymer of an ethylenically unsaturated monomer having a polar substituent. The reason why the above-mentioned cyclic organic compound is added to the above resin to suppress deterioration of visibility is determined as follows.

The reason why the visibility of the image display device is deteriorated is considered to be due to the uneven distribution of the low molecular compound in the coating layer (hardened layer) caused by the charging of the substrate of the optical film, resulting in minute coating. Uneven. In other words, when the compound to be added to the coating layer has a low molecular weight, the compound is likely to move in the coating layer due to charging of the substrate, and uneven distribution of the compound occurs, which causes coating unevenness. By adding a polymer compound (polymer of an ethylenically unsaturated monomer) to the coating layer, since the compound is a polymer, even if the substrate is charged, the compound is difficult to move in the coating layer (it is difficult to be affected by the charging of the substrate). ), while suppressing the uneven distribution of the compounds in the coating layer. Thereby, occurrence of minute coating unevenness can be suppressed, and deterioration of visibility of the image display device due to uneven coating can be suppressed.

Further, since the SP value of the polymer compound is within the above range, the compatibility of the curable resin with the above compound increases. Further, since the aromatic ring structure has a high polarity, the structure having a polar substituent in the alicyclic structure also has a high polarity, and by adding the above compound to the curable resin, the compatibility between the two is further increased. Therefore, it is considered that the uneven distribution of the above-mentioned compound in the coating layer is further suppressed, and it is considered that the occurrence of coating unevenness can be further suppressed and the deterioration of the visibility of the image display device can be further suppressed. Further, the SP value of the polymer compound is preferably in the range of 18.0 to 20.0 [(J/cm ³ ) ^1/2 ]. Further, the aromatic ring structure is more compatible with the curable resin than the structure having a polar substituent in the alicyclic structure, and is preferably effective in suppressing coating unevenness.

Further, when the substrate is a cellulose ester film, the cellulose ester film has high hygroscopicity and easily passes through moisture in a high-temperature and high-humidity environment, so that the polarizing performance of the polarizer is liable to lower due to the influence of the moisture. Therefore, the configuration of the present embodiment in which the effect of obtaining low moisture permeability in a high-temperature and high-humidity environment is very effective in the case where the substrate is a cellulose ester film.

Hereinafter, a specific configuration of an image display device using the optical film of the present embodiment will be described.

[Composition of image display device]

Fig. 1 is a cross-sectional view showing a schematic configuration of an image display device 1 of the present embodiment. The image display device 1 is, for example, a liquid crystal display device, and is configured by bonding the protective portion 3 to the polarizing plate 5 (to be described later on the optical film 15) of the liquid crystal display panel 2 via the filling layer 31. The filler 31 is an adhesive layer (void filler) composed of a photocurable resin such as acrylic, and is formed on the entire surface of the polarizing plate 5 of the liquid crystal display panel 2. The protective portion 3 protects the surface of the liquid crystal display panel 2, for example, a front panel made of acrylic resin or glass. Further, instead of the front panel, a touch panel (such as an electrostatic capacitance method or a resistive film method) may be used as the above-described protection portion 3.

The liquid crystal display panel 2 is configured by arranging polarizing plates 5 and 6 on both sides of liquid crystal cells 4 (display cells) on which a liquid crystal layer is sandwiched between a pair of substrates. The polarizing plate 5 is attached to one surface side (for example, the visual recognition side) of the liquid crystal cell 4 via the adhesive layer 7. The polarizing plate 6 is attached to the other surface side (for example, the backlight 9 side) of the liquid crystal cell 4 via the adhesive layer 8. The driving method of the liquid crystal display panel 2 is not particularly limited, and various driving methods such as an IPS (in-plane switching) type and a TN (twisted nematic) method can be employed.

The polarizing plate 5 is composed of a polarizing mirror 11 that penetrates a predetermined linearly polarized light, a film substrate 12 and a hardened layer 13 that are sequentially laminated on the side of the protective portion 3 of the polarizing mirror 11, and a liquid crystal cell 14 laminated on the polarizing mirror 11. The optical film 14 is formed on the side. The optical film 15 which is a protective film formed on the surface on the visual recognition side of the polarizing mirror 11 is constituted by the film substrate 12 and the hardened layer 13. Since the film substrate 12 is composed of a cellulose ester film, the film substrate 12 is also referred to as a cellulose ester film substrate. The surface of the polarizing plate 5 can be protected by providing the hardened layer 13 on the film substrate 12.

The film thickness of the film substrate 12 is preferably in the range of 5 to 34 μm. By thinning the film substrate 12, the optical film 15 and the polarizing plate 5 can be thinned, contributing to a reduction in thickness of the entire image display device 1.

The hardened layer 13 may be composed of a single layer as shown in FIG. 1, or two or more layers may be laminated on the film substrate 12. For example, as shown in FIG. 2, the hardened layer 13 can be formed by laminating the first hardened layer 13a and the second hardened layer 13b from the side of the film substrate 12. As described above, the plurality of layers of the hardened layer 13 can improve the scratch resistance, and the surface protection of the polarizing plate 5 by the optical film 15 can be reliably achieved.

The optical film 14 is provided to protect the back surface of the polarizing plate 5. The optical film 14 may be composed of the same material (for example, cellulose ester) as the film substrate 12, or may be composed of other materials.

The film substrate 12 described above can be composed of a λ/4 film. The λ/4 film is a layer which imparts an in-plane retardation of about 1/4 of the wavelength to the transmitted light. In the present embodiment, it is composed of a film which is obliquely extended. The angle (cross angle) between the slow axis of the λ/4 film and the absorption axis of the polarizer 11 is 30° to 60°, whereby the linear polarization from the polarizer 11 is λ/4 film (film substrate) 12) Convert to circular or elliptically polarized light.

Therefore, the observer wears a polarizing sun visor and observes the display. In the case of an image, even if the transmission axis of the polarizer 11 (perpendicular to the absorption axis) and the transmission axis of the polarizing sunshade are shifted, the light emitted from the polarizing plate 5 (circularly polarized or elliptically polarized) may be contained. The component of the light parallel to the transmission axis of the polarizing sunshade is introduced into the eye of the observer. Thereby, it is possible to suppress the display image from being difficult to see due to the observation angle. Further, even if the observer does not wear the polarizing sun visor, the person who enters the observer's eye from the polarizing plate 5 is circularly polarized or elliptically polarized, and the linearly polarized light directly enters the observer's eye. Compared, it can reduce the burden on the observer's eyes.

The polarizing plate 6 is formed by a polarizing mirror 21 that penetrates a predetermined linearly polarized light, an optical film 22 disposed on the liquid crystal cell 4 side of the polarizing mirror 21, and an optical film 23 disposed on the opposite side of the polarizing mirror 21 from the liquid crystal cell 4. Combined to form. The polarizer 21 is arranged such that the transmission axis is perpendicular to the polarizing mirror 11 (orthogonal Nicols state). The optical films 22 and 23 are provided to protect the front and back surfaces of the polarizing plate 6. These may be composed of the same material (for example, cellulose ester) as the film substrate 12 of the polarizing plate 5, or may be formed of other materials.

Furthermore, the optical film 15 described above can also be used for applications other than polarizing plates. At this time, the hardened layer 13 may be provided on both sides of the film substrate 12. Therefore, in the optical film 15, the hardened layer 13 may be formed on at least one side of the film substrate 12.

[Optical film]

Hereinafter, the details of the optical film 15 described above will be described.

(hardened layer)

The hardened layer of the present embodiment contains active energy having an alicyclic structure A line curable resin (hereinafter, only described as a curable resin). Specific examples of the alicyclic structure include a norbornyl group, a tricyclic fluorenyl group, a tetracyclododecyl group, a pentacyclic group, an adamantyl group, a diadamantyl group, and the like.

The active energy ray-curable resin preferably has an ethylenically unsaturated double bond. The ethylenically unsaturated double bond group may, for example, be a polymerizable functional group such as a (meth)acryl fluorenyl group, a vinyl group, a styryl group or an allyl group, and among them, a (meth) acrylonitrile group and a group are preferable. C(O)OCH=CH ₂ .

The active energy ray-curable resin having an alicyclic structure preferably has a hydrocarbon group having an alicyclic structure and a group having an ethylenically unsaturated double bond bonded via a linking group. Examples of the linking group include a single bond, an alkylene group, a decylamino group, an amine carbaryl group, an ester group, an oxycarbonyl group, an ether group, and the like, or a combination thereof. Specifically, it may be a polyol having a diol structure such as an alicyclic structure, a triol or the like, a carboxylic acid having a (meth) acrylonitrile group, a vinyl group, a styryl group, an allyl group or the like, a carboxylic acid derivative, or the like. An epoxy derivative, an isocyanate derivative compound or the like can be easily synthesized by one or two-stage reaction.

Hereinafter, specific compounds of the active energy ray-curable resin having an alicyclic structure are represented by the following general formulae (I) to (VII), but the present invention is not limited thereto.

(wherein R1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R2 is an alkylene group having 1 to 5 carbon atoms; or an alkylene oxide group; and R3 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Is an integer of 1 or 2).

(wherein R1, R3 and n are the same definitions as in the above formula (I)).

In the general formula (I) and the general formula (II), R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group. R2 represents an alkylene group or an alkylene oxide group having 1 to 5 carbon atoms, preferably a methylene group, a vinyl group, a formaldehyde group or an oxirane group. R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group.

Hereinafter, preferred specific examples of the compound represented by the formula (I) are shown, but the invention is not limited thereto.

Hereinafter, preferred specific examples of the compound represented by the formula (II) are shown, but the invention is not limited thereto.

For example, NK Ester A-DCP (tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.), etc., may be mentioned as a commercial product of the compound represented by the above formula (I) or (II). Not subject to these restrictions.

In the formula (III), L and L' each independently represent a divalent or higher linking group, and are not divalent at the same time. n represents an integer from 1 to 3.

In the formula (IV), L and L' each independently represent a divalent or higher linking group, and are not divalent at the same time. n represents an integer from 1 to 2.

In the general formula (V), L and L' each independently represent a divalent or higher linking group, and are not divalent at the same time. n represents an integer from 1 to 2.

In the formula (VI), L, L' and L" each independently represent a divalent or higher linking group.

In the formula (VII), L and L' each independently represent a divalent or higher linking group, and are not divalent at the same time.

Specific examples of the compounds represented by the above formulas (III) to (VII) are shown below, but are not limited thereto.

The hardened layer preferably contains 30% by mass or more of an active energy ray-curable resin having an alicyclic structure, and more preferably 50% by mass or more.

The hardened layer is a mechanical film strength (scratch resistance, pencil hardness) in addition to the above-described active energy ray-curable resin having an alicyclic structure. In addition, the ultraviolet curable resin described below may be contained in the range which does not impair the effect of this invention. As the ultraviolet curable resin, for example, an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, and an ultraviolet curable epoxy acrylate resin are preferably used. The ultraviolet curable polyol acrylate resin or the ultraviolet curable epoxy resin is preferably an ultraviolet curable acrylate resin.

As the ultraviolet curable acrylate resin, a polyfunctional acrylate is preferred. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate.

Here, the polyfunctional acrylate is a compound having two or more acryloxy groups or methacryloxy groups in the molecule. Examples of the monomer of the polyfunctional acrylate include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and the like. Hydroxymethylpropane triacrylate, trimethylolethane triacrylate, tetramethylol methane triacrylate, tetramethylol methane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate Ester, pentaerythritol tri/tetraacrylate, trimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerol triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, Dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol Acrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolethane methane Acrylate, tetramethylol methane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol trimethacrylate Dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol pentamethyl acrylate, dipentaerythritol hexamethacrylate, polybasic acid acrylate, and the like. Further, a monofunctional acrylate can also be used. Examples of the monofunctional acrylate include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, and phenoxy acrylate. Ester, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, cyclohexyl acrylate, and the like. Such a monofunctional acrylate system can be obtained from Nippon Kasei Co., Ltd., Shin-Nakamura Chemical Industry Co., Ltd., Osaka Organic Chemical Industry Co., Ltd., and the like.

(cyclic organic compounds)

The hardened layer has a cyclic organic compound having an SP value of 17.0 to 21.0 [(J/cm ³ ) ^1/2 ] and having at least one aromatic ring structure or a polar substituent in the alicyclic structure.

<SP value>

The SP value is expressed by the square root of the molar internal energy of each atom divided by the volume, indicating the polarity per unit volume. This SP value is also called a Solubility Parameter, and is used as a scale indicating the intermolecular force when a force acting between a solvent and a solute is assumed to be an intermolecular force (regular solution theory). Empirically, it is known that the smaller the difference between the SP values of the two components, the greater the solubility (the two components are easily mixed). SP value, for example It can be calculated by FUJITSU Technical Conputing Solution SCIGRESS (made by Fujitsu Co., Ltd.).

From the viewpoint of improving the compatibility with the above-described active energy ray-curable resin having an alicyclic structure, the SP value of the above cyclic organic compound is preferably in the range of 18.0 to 20.0 [(J/cm ³ ) ^1/2 ]. .

<Aromatic Ring Structure>

The aromatic ring structure of the cyclic organic compound may be a structure containing one or more monocyclic or polycyclic rings exhibiting aromaticity. For example, a benzene-based aromatic ring having one or a plurality of aromatic rings condensed or linked in a benzene ring in the structure, or a heteroaromatic ring having an element other than carbon in a ring structure may be mentioned. The number of aromatic rings which are preferably condensed or linked by a benzene ring is usually from 1 to 5, more preferably from 1 to 3.

<Structure having a polar substituent in an alicyclic structure>

The alicyclic structure of the cyclic organic compound may be a structure containing one or more cycloalkanes or cycloolefins. Specific examples of the alicyclic structure are shown below, but are not limited thereto.

Examples of the monocyclic cycloalkane include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cyclopentane, cyclooctane, cyclodecane, cyclodecane, cycloundecane, and cyclododecane. Wait. Examples of the monocyclic cycloolefin include cyclopropene, cyclobutene, cyclopropene, cyclohexene, cycloheptene, and cyclooctene. As the alicyclic structure, cyclohexane and cyclohexene are preferred. Furthermore, the alicyclic structure is not limited to a single ring, and may be a multiple ring. Examples of the polycyclic structure include bicyclodecane, norbornene, norbornadiene and the like.

The polar substituent may, for example, be a hydroxyl group, a carbonyl group, a carboxyl group, an amine group, a nitro group or a nitrile group, but is not limited thereto. Preferred as hydroxy Base, carboxyl group.

<Ethylene unsaturated monomer>

The above cyclic organic compound is a polymer of an ethylenically unsaturated monomer. Examples of the ethylenically unsaturated monomer include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. , n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, (meth)acrylic acid N-octyl ester, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, (Meth)acrylic acid tolylmethyl methacrylate, benzyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, (methyl) a (meth)acrylic monomer such as octadecyl acrylate or glycidyl (meth)acrylate; a styrene monomer such as styrene, vinyl toluene or α-methylstyrene; pentaerythritol triacrylate , pentaerythritol tetraacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, trimethylolpropane tetra(meth)acrylate, dipentaerythritol hexaacrylate Methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl acrylate, acrylic acid Octadecyl ester, 1,6-hexanediol dimethacrylate, urethane acrylate, but are not limited by these. Preferred is (meth)acrylic acid or methyl (meth)acrylate.

The ethylenically unsaturated monomer preferably contains at least one of each of the structures of coumarone, anthracene, styrene, vinyltoluene, isoprene, piperylene, and decene. As a terpene structure, a β-pinene structure is mentioned. Manufacture, α-pinene structure, β-limonene structure, α-limonene structure. Further, the hydrogenated terpene structure obtained by hydrogen reduction can also be constructed for this purpose.

Specific examples of the cyclic organic compound usable in the present embodiment are shown below, but the cyclic organic compound is not limited thereto.

As a commercial item of the above-mentioned cyclic organic compound, YS Resin TO125, YS Resin TO115, YS Resin TO105, YS Resin TO85, YS Resin TR105, Clearon K4100, Clearon K100, manufactured by YASUHARA CHEMICAL CO., LTD. YS Polyster T80, YS Polyster UH115, YS Polyster NH, YS Resin SX100, YS Resin SX185, Nittoresin Cumarone V-120S, Nittaresin PH-25, Nitorresin PH-30-90T, Dongcao Co., Ltd. The company's Petcol, Petrotec, etc., are not subject to these restrictions.

(photopolymerization initiator)

For the hardening promotion of the active wire hardening resin, the hardened layer preferably contains a photopolymerization initiator. The content of the photopolymerization initiator is preferably a photopolymerization initiator: active line curing resin = 20:100 to 0.01:100 by mass ratio. Specific examples of the photopolymerization initiator include alkylphenones, acetophenones, diphenylketones, hydroxydiphenylketones, Michler's ketones, α-amyl oxime esters, thioxanthone, and the like. Derivatives, etc., are not specifically limited by these. Commercially available products can be used as the photopolymerization initiator, and examples thereof include Irgacure 184, Irgacure 907, Irgacure 651 manufactured by BASF Japan Co., Ltd., and the like.

(microparticles)

The hardened layer may also contain microparticles. The fine particles are not particularly limited, and examples thereof include cerium oxide, aluminum oxide, zirconium oxide, titanium oxide, and antimony pentoxide, and cerium oxide is preferred. The cerium oxide microparticles may also be hollow particles having voids inside. The fine particles coated with the polymer decane coupling agent are particularly excellent in exhibiting good mechanical properties. Regarding the content, it is a fine particle: active wire hardening resin = 0.1: 100 to 400: 100.

(polymer decane coupling agent)

The so-called polymer decane coupling agent refers to a polymerizable monomer and decane. The reactant of the coupling agent (reactive decane compound). Such a polymer decane coupling agent can be obtained, for example, according to a method for producing a reactant of a polymerizable monomer and a reactive decane compound disclosed in Japanese Laid-Open Patent Publication No. Hei 11-116240.

Specific examples of the polymerizable monomer include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. , n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, (meth)acrylic acid N-octyl ester, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, (Meth)acrylic acid tolylmethyl methacrylate, benzyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, (methyl) 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, octadecyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate , ethylene oxide adduct of (meth)acrylic acid, trifluoromethyl methyl (meth)acrylate, 2-trifluoromethyl ethyl (meth)acrylate, 2-perfluoro (meth)acrylate Ethyl ethyl ester, 2-perfluoroethyl-2-perfluorobutyl (meth)acrylate Ester, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethyl methyl (meth)acrylate, 2-perfluoromethyl-2 (meth)acrylate -Perfluoroethyl methyl ester, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, etc. (meth)acrylic monomer; styrene monomer such as styrene, vinyl toluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and salts thereof; perfluoroethylene, perfluoropropylene a fluorine-containing vinyl monomer such as vinylidene fluoride; a fluorene-containing vinyl monomer such as vinyl trimethoxy decane or vinyl triethoxy decane; maleic anhydride, maleic acid, monoalkyl ester and dialkyl ester of maleic acid; fumaric acid, fumar Acid monoalkyl and dialkyl esters; maleimide, methyl maleimide, ethyl maleimide, propyl maleimide, butyl maleimide, hexyl Nitrile containing imidamine, octylmaleimide, dodecamadamine, octadecylimine, phenylmaleimide, cyclohexylmaleimide, etc. a vinyl-based monomer; a mercaptoamine-containing vinyl monomer such as acrylamide or methacrylamide; vinyl acetate, vinyl propionate, trimethyl vinyl acetate, vinyl benzoate, cinnamon Vinyl esters such as vinyl acetate; olefins such as ethylene and propylene; conjugated dienes such as butadiene and isoprene; vinyl chloride, vinylidene chloride, allyl chloride, allyl alcohol, Acrylic resin monomers; pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tri(meth)acrylate, pentaerythritol tetraacrylate, ruthenium tris Propane tetra(meth)acrylate, dipentaerythritol hexaacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate , isodecyl methacrylate, propylene laurate, n-octadecyl acrylate, 1,6-hexanediol dimethacrylate, methacrylic perfluorooctyl acetate, trifluoroethyl methacrylate Esters, urethane acrylates, and the like, and mixtures thereof.

As the reactive decane compound, an organic ruthenium compound represented by the following formula (1) is preferably used.

XR-Si(OR) ₃ (1) (wherein R represents an organic group having 1 to 10 carbon atoms selected from a substituted or unsubstituted hydrocarbon group; and X represents a (meth) acrylonitrile group, an epoxy group ( One or two or more functional groups selected from glycidyl groups, urethane groups, amine groups, and fluorine groups).

Specific examples of the organic hydrazine compound represented by the formula (1) include 3,3,3-trifluoropropyltrimethoxydecane and methyl-3,3,3-trifluoropropyldimethoxydecane. , β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, γ-glycidoxymethyltrimethoxydecane, γ-glycidoxymethyltriethoxydecane, Γ-glycidoxyethyltrimethoxydecane, γ-glycidoxyethyltriethoxydecane, γ-glycidoxypropyltrimethoxydecane, γ-glycidoxy Propyltrimethoxydecane, γ-glycidoxypropyltriethoxydecane, γ-glycidoxypropyltriethoxydecane, γ-(β-glycidoxyethoxy) ) propyl trimethoxy decane, γ-(meth) propylene methoxymethyl trimethoxy decane, γ-(meth) propylene methoxymethyl triethoxy decane, γ-(meth) propylene醯 oxyethyl trimethoxy decane, γ-(meth) propylene methoxyethyl triethoxy decane, γ-(methyl) propylene methoxy propyl trimethoxy decane, γ- (methyl ) acryloxypropyltrimethoxydecane, γ-(meth)acryloxypropyltriethoxydecane, γ-(A) Propylene methoxy propyl triethoxy decane, 3-ureido isopropyl propyl triethoxy decane, perfluorooctyl ethyl trimethoxy decane, perfluorooctyl ethyl triethoxy decane , perfluorooctylethyl triisopropoxydecane, trifluoropropyltrimethoxydecane, N-β(aminoethyl)γ-aminopropylmethyldimethoxydecane, N-β ( Aminoethyl) gamma-aminopropyltrimethoxydecane, N-phenyl-gamma-aminopropyltrimethoxydecane, and the like, and mixtures thereof.

The polymerizable monomer is reacted with a reactive decane compound to prepare a polymer decane coupling agent. Specifically, an organic solvent solution in which a reactive decane compound is mixed in an amount of 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer, and a polymerization initiator may be added thereto. , obtained by heating.

(Modulation method of polymer decane coupling agent coated microparticles)

The polymer decane coupling agent coats the fine particles, and specifically, the polymer decane coupling agent is added to the organic solvent dispersion of the fine particles, and the fine particles are coated with the polymer decane coupling agent in the presence of a base. The average particle diameter of the polymer decane coupling agent-coated fine particles obtained is preferably in the range of 5 to 500 nm, more preferably 10 to 200 nm, which is preferable in that optical characteristics for the optical film can be secured.

The content of the polymer decane coupling agent-coated fine particles in the hardened layer is preferably from 0.5 to 80 parts by mass, more preferably from 1 to 60 parts by mass, based on the solid content, which is preferable from the viewpoint of ensuring the film strength of the hardened layer.

(conductive agent)

In the hardened layer, a conductive agent may be contained in order to impart antistatic properties. Preferred examples of the conductive agent include metal oxide particles or π-conjugated conductive polymers. Further, the ionic liquid can also be preferably used as a conductive compound.

(additive)

In the hardened layer, a fluorine-oxymethane graft compound, a fluorine compound, a rhodium compound or a compound having an HLB value of 3 to 18 may be contained from the viewpoint of improving coatability. The hydrophilicity is easily controlled by adjusting the kind or amount of these additives. The so-called HLB value is Hydrophile-Lipophile-Balance, a balance of hydrophilicity-lipophilicity, indicating the value of the hydrophilicity or lipophilicity of the compound. The smaller the HLB value, the higher the lipophilicity, and the higher the value, the higher the hydrophilicity. Further, the HLB value can be obtained by a calculation formula as follows.

HLB=7+11.7Log(Mw/Mo)

In the formula, Mw represents the molecular weight of the hydrophilic group, Mo represents the molecular weight of the lipophilic group, and Mw + Mo = M (molecular weight of the compound). Alternatively, according to the Griffin method, the sum/molecular weight of the formula of HLB value = 20 × hydrophilic portion (J. Soc. Cosmetic Chem., 5 (1954), 294) may be mentioned.

Specific compounds of the compounds having an HLB value of from 3 to 18 are listed below, but are not limited thereto. ( ) indicates the HLB value. Kao Co., Ltd.: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), Emulgen 105 (9.7), Emulgen 106 (10.5), Emulgen 108 (12.1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2), Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0) ), Emulgen 409PV (12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5), Emulgen 707 (12.1), Emulgen 709 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4) ), Emulgen 1135S-70 (17.9) Emulgen 2020G-HA (13.0), Emulgen 2025G (15.7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), Nissin Chemical Industrial Co., Ltd.: Surfynol 104E (4), Surfynol 104H (4), Surfynol 104A (4), Surfynol 104BC (4), Surfynol 104 DPM (4), Surfynol 104 PA (4), Surfynol 104 PG-50 (4), Surfynol 104S (4), Surfynol 420 (4), Surfynol 440 (8), Surfynol 465 (13), Surfynol 485 (17), Surfynol SE (6), Shin-Etsu Chemical Co., Ltd.: X-22-42 72(7), X-22- 6266 (8).

The fluoro-nonane oxide grafting compound refers to a grafting of a polyoxyalkylene oxide and/or an organic polyoxyalkylene containing at least a fluorine-based resin and a polysiloxane. A compound of the resulting copolymer. Such a fluorine-nonane oxide graft compound can be prepared by a method as described in the examples below. Alternatively, commercially available products include ZX-022H, ZX-007C, ZX-049, and ZX-047-D manufactured by Fuji Chemical Industry Co., Ltd.

Examples of the fluorine-based compound include Megafac series (F-477, F-487, F-569, etc.) manufactured by DIC Corporation, Optool DSX manufactured by DAIKIN Industries Co., Ltd., and Optool DAC.

Examples of the oxime-based compound include: Shin-Etsu Chemical Co., Ltd.: KF-351, KF-352, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-618, KF -6011, KF-6015, KF-6004, BYK Chemical Japan Co., Ltd.: BYK-UV3576, BYK-UV3535, BYK-UV3510, BYK-UV3505, BYK-UV3500, BYK-UV3510, etc. These components are preferably added in a range of 0.005 parts by mass or more and 10 parts by mass or less based on the solid content in the hard layer composition. These components may be added in two or more types as long as the total additive amount is in the range of 0.005 parts by mass or more and 10 parts by mass or less.

(UV absorber)

The hardened layer may also contain an ultraviolet absorber described in the cellulose ester film described later. In the case of a film containing a UV absorber, when the cured layer is composed of two or more layers, it is preferred to contain an ultraviolet absorber in the hardened layer which is in contact with the film substrate.

The content of the ultraviolet absorber is preferably a content of a UV absorber: a curable resin = 0.01:100 to 20:100 in terms of a mass ratio.

(solvent)

The hardened layer is preferably obtained by diluting the component forming the hardened layer into a hardened layer by a solvent for swelling or partially dissolving the film substrate, and coating, drying, and hardening the film substrate by the following method. .

As the solvent, a ketone (methyl ethyl ketone, acetone, etc.) and/or an acetate (methyl acetate, ethyl acetate, butyl acetate, etc.), an alcohol (ethanol, methanol, n-propanol, isopropyl) is preferred. Alcohol), propylene glycol monomethyl ether, cyclohexanone, methyl isobutyl ketone, and the like. The coating amount of the hardened layer composition is suitably from 0.1 to 80 μm in terms of wet film thickness, and is preferably from 0.5 to 30 μm in terms of wet film thickness. Further, the dry film thickness is in the range of 0.01 to 20 μm in average film thickness, preferably in the range of 1 to 15 μm. More preferably, it is in the range of 2 to 12 μm.

As a coating method of the hardened layer composition, a well-known method such as a gravure coater, a dip coater, a reverse coater, a bar coater, a die coater, an inkjet method, or the like can be used.

(lamination)

When the hardened layer is composed of two or more layers, it is preferable from the viewpoint of surface hardness (scratch resistance). When the hardened layer is composed of two or more layers, the outermost layer contains the polymer decane coupling agent-coated fine particles, and is preferably from the viewpoint of surface hardness. The content of the polymer decane coupling agent coated fine particles is preferably a polymer decane coupling agent coated fine particles by mass ratio: curable resin =0.1:100~200:100 range.

When two or more hardened layers are provided, the thickness of the hardened layer in contact with the cellulose ester film substrate is preferably in the range of 0.01 to 50 μm, and the thickness of the cured layer in the second layer is preferably in the range of 0.01 to 25 μm.

Two or more layers of lamination may be simultaneously laminated. In the simultaneous lamination, two or more hard layers are applied to the substrate by wet on wet without a drying step to form a hardened layer.

On the first hardened layer, when the second hardened layer is laminated with a wet cover wet without a drying step, it is simply laminated by an extrusion coater or by a slit die having a plurality of slits. Stack at the same time.

(hardening layer forming method)

After the application of the hardened layer composition, drying and hardening (irradiation of active wire (also referred to as UV hardening treatment)) may be performed, and if necessary, heat treatment may be performed after UV curing. The heat treatment temperature after the UV curing is preferably 80 ° C or higher, more preferably 100 ° C or higher, and particularly preferably 120 ° C or higher. A hardened layer excellent in film strength can be obtained by heat treatment after UV curing at such a high temperature.

Drying is preferably carried out at a temperature of 30 ° C or higher in the decrement drying section. The temperature in the decrement drying section is more preferably 50 ° C or more.

In general, it is known that if the drying process is started, the drying speed is gradually changed from the state of being fixed to the state of being reduced. The section in which the drying speed is fixed is referred to as a constant-rate drying section, and the section in which the drying speed is decreased is referred to as a reduction-rate drying section.

As a light source of the UV hardening treatment, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a carbon arc lamp, a metal can be used. Halides, xenon lamps, etc.

The irradiation conditions differ depending on the respective lamps, but the irradiation amount of the active rays is usually in the range of 50 to 1000 mJ/cm ² , preferably in the range of 50 to 300 mJ/cm ² . Further, in the UV curing treatment, oxygen removal (for example, replacement by an inert gas such as nitrogen purge) may be performed in order to prevent a reaction disorder caused by oxygen. The hardened state of the surface can be controlled by adjusting the amount of removal of the oxygen concentration.

When the active wire is irradiated, it is preferable to carry out the tension while the film is conveyed, and it is more preferable to apply the tension in the width direction. The tension applied is preferably from 30 to 300 N/m. The method of imparting the tension is not particularly limited, and the tension can be given in the conveying direction on the rear roller, or the tension can be given in the width direction or the biaxial direction by the tenter. Thereby, a film having more excellent planarity can be obtained.

In the optical film, the hardened layer may have at least one layer, and may be composed of a plurality of layers. Further, a hardened layer may be provided on both surfaces of the optical film.

(back coating)

Preferably, a back coat layer is provided on the surface of the optical film opposite to the side on which the hardened layer is provided. The back coat layer is provided for correcting curl occurring due to the provision of the hardened layer or other layers by coating, CVD, or the like. That is, by making the surface provided with the back coat layer inner, it has a rounded property, and the degree of curling can be balanced. Further, the back coat layer is preferably applied as an anti-blocking layer. In this case, it is preferred to add fine particles having an anti-blocking function to the back coat coating composition.

Examples of the inorganic compound added to the back coat layer include cerium oxide, titanium oxide, aluminum oxide, and oxidation. Zirconium, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium citrate, tin oxide, indium oxide, zinc oxide, ITO, hydrated calcium citrate, aluminum citrate, magnesium citrate and calcium phosphate. The microparticles contain a ruthenium, preferably at a point where the haze is low, and particularly preferably ruthenium dioxide. For the fine particles, for example, those commercially available under the trade names of Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Japan AEROSIL Co., Ltd.) can be used. As the fine particles of zirconia, for example, those sold under the trade names of Aerosil R976 and R811 (manufactured by Japan Aerosil Co., Ltd.) can be used. Examples of the polymer fine particles include a fluorinated resin, a fluororesin, and an acrylic resin. Preferably, the epoxy resin is particularly preferably a three-dimensional network structure, for example, Tosperl 103, the same 105, the same 108, the same 120, the same 145, the same 3120, and the same 240 (the above Toshiba Oxygen) The product name of the system is marketed.

Among them, Aerosil 200V and Aerosil R972V are particularly suitable for use because they maintain a low haze and have a high anti-adhesion effect. The dynamic friction coefficient of the back side of the optical film used in the present embodiment is preferably 0.9 or less, and particularly preferably 0.1 to 0.9.

The fine particles contained in the back coat layer are preferably contained in an amount of 0.1 to 50% by mass, more preferably 0.1 to 10% by mass, based on the binder. The increase in haze at the time of providing the back coat layer is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.0 to 0.1%.

The back coat layer is specifically preferably formed by coating a composition containing a solvent for dissolving the transparent resin film or a solvent for swelling. The solvent to be used may be a mixture of a solvent to be dissolved and/or a solvent to swell, and a solvent which does not dissolve, as long as it is based on the degree of curling of the transparent resin film or the kind of the resin. It may be formed by mixing the composition and the coating amount in an appropriate ratio.

In order to enhance the curl prevention function, it is effective to increase the mixing ratio of the solvent which dissolves the solvent composition used and/or the solvent which swells, and to reduce the ratio of the solvent which does not dissolve. The mixing ratio is preferably (the solvent to be dissolved and/or the solvent to be swollen): (the solvent which does not dissolve) = 10:0 to 0.3:9.7. As a solvent which dissolves or swells the transparent resin film contained in such a mixed composition, for example, there are two Alkane, acetone, methyl ethyl ketone, N,N-dimethylformamide, methyl acetate, ethyl acetate, cyclohexane, diacetone alcohol, 1,3-dioxolane, N-methyl Pyrrolidone, propylene glycol monomethyl ether acetate, propyl carbonate, cyclopentanone, 3-pentanone, 1,2-dimethoxyethane, tetrahydrofuran, ethyl lactate, bis(2-methoxy Ethyl ethyl) ether, 2-methoxyethyl acetate, propylene glycol dimethyl ether, trichloroethylene, dichloromethane, dichloroethane, tetrachloroethane, trichloroethane, chloroform, and the like. Examples of the solvent which does not dissolve include methanol, ethanol, n-propanol, isopropanol, n-butanol, propylene glycol monomethyl ether, or hydrocarbons (toluene, xylene, cyclohexanol).

The coating composition is preferably a wet film thickness of 1 to 100 μm, particularly preferably 5 to 30 μm, using a gravure coater, a dip coater, a reverse coater, a bar coater, a die coater, or the like. The surface of the transparent resin film. The back coat layer may also contain a resin as a binder. Examples of the resin used for the binder of the back coat layer include a vinyl chloride-vinyl acetate copolymer, a vinyl chloride resin, a vinyl acetate resin, a copolymer of vinyl acetate and vinyl alcohol, and a partially hydrolyzed vinyl chloride- Vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, ethylene-vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymerization Ethylene-based polymer or copolymer, nitrocellulose, cellulose acetate propionate (preferably having an acetyl group substitution degree of 1.8 to 2.3, a propylene group substitution degree of 0.1 to 1.0), and a diethyl fluorene fiber Cellulose acetate butyric acid a cellulose derivative such as an ester resin, a copolymer of maleic acid and/or acrylic acid, an acrylate copolymer, an acrylonitrile-styrene copolymer, a chlorinated polyethylene, an acrylonitrile-chlorinated polyethylene-styrene copolymer , methyl methacrylate-butadiene-styrene copolymer, acrylic resin, polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane Rubber system such as ester resin, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amine resin, styrene-butadiene resin, butadiene-acrylonitrile resin Resin, oxime resin, fluorine resin, etc. are not limited by these. For example, as acrylic resin, Acrytpet MD, VH, MF, V (manufactured by Mitsubishi Rayon Co., Ltd.), Hiperl M-4003, M-4005, M-4006, M-4202, M-5000, M-5001, M -4501 (made by Gensei Industrial Co., Ltd.), Dianal BR-50, BR-52, BR-53, BR-60, BR-64, BR-73, BR-75, BR-77, BR-79, BR- 80, BR-82, BR-83, BR-85, BR-87, BR-88, BR-90, BR-93, BR-95, BR-100, BR-101, BR-102, BR-105, Acrylic acid and methyl group of BR-106, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118, etc. (Mitsubishi Laiyang Co., Ltd.) Various kinds of homopolymers and copolymers produced by using an acrylic monomer as a raw material are commercially available, and a preferred monomer can be appropriately selected from them. A cellulose resin layer such as diacetyl cellulose or cellulose acetate propionate is preferred.

The order of applying the back coat layer may be before or after applying the hard layer on the opposite side of the back coat layer of the optical film, but when the back coat layer also serves as the anti-blocking layer, it is preferably applied first. Alternatively, the back coat layer may be applied in two or more portions before and after the application of the hard coat layer.

[Optical film properties] (surface shape)

The arithmetic mean roughness Ra (JIS B0601: 2001) of the hardened layer is preferably in the range of 2 to 100 nm, particularly preferably in the range of 2 to 20 nm. It is excellent in visibility or transparency by the arithmetic mean roughness Ra of the said range. The arithmetic mean roughness Ra is a value measured by an optical interference type surface roughness meter (manufactured by ZYGO Co., New View) in accordance with JIS B0601:2001.

(haze)

The haze of the optical film is preferably in the range of 0.05% to 10% from the viewpoint of visibility for use in an image display device. The haze can be measured in accordance with JIS K7105 and JIS K7136.

(hardness)

Regarding the hardness of the optical film, the pencil hardness of the hardness index is preferably HB or more. If the pencil hardness is HB or more, it is not easily damaged in the polarizing plate forming step. The pencil hardness was adjusted for 2 hours or more under the conditions of a temperature of 23 ° C and a relative humidity of 55%, and the test pencil specified in JIS S6006 was used under the condition of 500 g of weighting, and the pencil according to JIS K5400 was used. The hardness evaluation method measures the value of the hardened layer.

[Cellulose ester film substrate (hereinafter also referred to as film substrate)]

The film substrate has a cellulose ester as a main component. For example, a cellulose diacetate film, a cellulose triacetate film, a cellulose acetate propionate film, and a cellulose acetate butyrate film are mentioned.

As a commercial item of a cellulose ester film, Konica-Minolta KC8UX, KC4UX, KC8UY, KC4UY, etc. are mentioned, for example. KC6UA, KC4UA, KC2UA, KC4UE and KC4UZ (above, Konica-Minolta). The refractive index of the cellulose ester film is preferably from 1.45 to 1.55. The refractive index system can be measured in accordance with JIS K7142-2008.

(cellulose ester resin)

The cellulose ester resin (hereinafter also referred to as cellulose ester or cellulose resin) is preferably a lower fatty acid ester of cellulose. The so-called lower fatty acid means a fatty acid having 6 or less carbon atoms. As the lower fatty acid ester of cellulose, for example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, or the like, or cellulose acetate C can be used. A mixed fatty acid ester of an acid ester, cellulose acetate butyrate or the like. A lower fatty acid ester of cellulose which is particularly preferably used is cellulose diacetate, cellulose triacetate, cellulose acetate propionate. These cellulose esters can be used singly or in combination.

Cellulose diacetate is preferably used in an average degree of acetylation (combined amount of acetic acid) of 51.0% to 56.0%. Commercially available products include L20, L30, L40, and L50 manufactured by DAICEL, and Ca398-3, Ca398-6, Ca398-10, Ca398-30, and Ca394-60S manufactured by Japan Chemical Co., Ltd.

Cellulose triacetate is preferably used in an average degree of acetylation (combined amount of acetic acid) of 54.0 to 62.5%, more preferably cellulose triacetate having an average degree of acetylation of 58.0 to 62.5%.

The cellulose triacetate preferably contains cellulose triacetate A and cellulose triacetate B. The cellulose triacetate A coefficient has an average molecular weight (Mn) of 125,000 or more and less than 155,000, a weight average molecular weight (Mw) of 265,000 or more and less than 310,000, and a cellulose triacetate having a Mw/Mn of 1.9 to 2.1. . Cellulose triacetate B-based thiol group substitution The cellulose triacetate having a degree of 2.75 to 2.90, a Mn of 155,000 or more and less than 180,000, a Mw of 290,000 or less and less than 360,000, and a Mw/Mn of 1.8 to 2.0.

Cellulose acetate propionate, when a fluorenyl group having 2 to 4 carbon atoms is used as a substituent, a degree of substitution of an ethane group is X, and a degree of substitution of a fluorenyl group or a butyl group is Y, it is preferred to simultaneously satisfy the following Formulas (I) and (II).

Formula (I) 2.6≦X+Y≦3.0

Formula (II) 0≦X≦2.5

Among them, it is preferably 1.9 ≦ X ≦ 2.5, 0.1 ≦ Y ≦ 0.9.

The method for measuring the degree of substitution of the above thiol group can be determined in accordance with ASTM-D817-96. The number average molecular weight (Mn) and molecular weight distribution (Mw) of the cellulose ester can be determined using high speed liquid chromatography. The measurement conditions are as follows.

Solvent: dichloromethane

Column: Shodex K806, K805, K803G

(using the Showa Denko (share) system to connect 3)

Column temperature: 25 ° C

Sample concentration: 0.1% by mass

Detector: RI Model 504 (manufactured by GL Scientific Co., Ltd.)

Pump: L6000 (Hitachi Manufacturing Co., Ltd.)

Flow rate: 1.0ml/min

Calibration curve: A calibration curve of 13 samples up to standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 1000000 to 500. The 13 samples are preferably used at approximately equal intervals.

(thermoplastic acrylic resin)

The film substrate can also be used in a cellulose ester resin with a thermoplastic acrylic tree Made up of fat. When used in combination, the mass ratio of the thermoplastic acrylic resin to the cellulose ester resin is preferably thermoplastic acrylic resin: cellulose ester resin = 95:5 to 50:50.

In the acrylic resin, a methacrylic resin is also included. The acrylic resin is not particularly limited, but is preferably composed of 50 to 99% by mass of methyl methacrylate unit and 1 to 50% by mass of other monomer units copolymerizable therewith. Examples of the other monomer which can be copolymerized include an alkyl methacrylate having an alkyl group number of 2 to 18, an alkyl acrylate having an alkyl number of 1 to 18, an acrylic acid, methacrylic acid or the like. An aromatic vinyl compound such as an unsaturated group-containing dicarboxylic acid such as β-unsaturated acid, maleic acid, fumaric acid or itaconic acid, styrene or α-methylstyrene, or acrylonitrile. An α,β-unsaturated nitrile such as methacrylonitrile, maleic anhydride, maleic imine, N-substituted maleimide, glutaric anhydride or the like may be used alone or in combination of two or more.

Among these, from the viewpoint of heat decomposition resistance or fluidity of the copolymer, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, second butyl acrylate, acrylic acid 2 are preferred. Ethylhexyl ester or the like, particularly preferably methyl acrylate or n-butyl acrylate. Further, the weight average molecular weight (Mw) is preferably from 80,000 to 500,000, more preferably from 110,000 to 500,000.

The weight average molecular weight of the acrylic resin can be determined by gel permeation chromatography. As a commercial item of the acrylic resin, for example, Delpet 60N, 80N (made by Asahi Kasei Chemicals Co., Ltd.), Dianal BR52, BR80, BR83, BR85, BR88 (manufactured by Mitsubishi Rayon Co., Ltd.), KT75 (Electrical Chemical Industry) (share) system, etc. Two or more types of acrylic resins may be used in combination.

(λ/4 film)

As the cellulose ester film substrate, a λ/4 film can also be used, and when the optical film of the present embodiment is incorporated into an image display device, not only the visibility is excellent but also the crosstalk is used. The point of excellence is also preferred.

The λ/4 film refers to a film having a phase difference of about 1/4 in the plane of the wavelength of the specified light (usually in the visible light range). In order to obtain substantially complete circularly polarized light in the wavelength range of visible light, the λ/4 film is preferably a broadband λ/4 film having a phase difference of about 1/4 of the wavelength in the wavelength range of visible light.

The in-plane hysteresis value R0 (550) measured by the λ/4 film at a wavelength of 550 nm is preferably in the range of 60 nm or more and 220 nm or less, more preferably in the range of 80 nm or more and 200 nm or less, and particularly preferably in the range of 90 nm or more and 190 nm or less. Furthermore, the in-plane hysteresis value Ro is represented by the following equation.

Ro=(nx-ny)×d

However, in the formula, nx and ny are among the refractive indices of 23 ° C, 55% RH, and 550 nm, the maximum refractive index in the in-plane of the film (also referred to as the refractive index in the slow axis direction), and in the film plane. The refractive index in the direction orthogonal to the slow axis, d is the thickness (nm) of the film. The Ro system can be calculated by measuring the birefringence at each wavelength in an environment of 23 ° C and 55% RH using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.).

Further, in order to function effectively as the λ/4 film, it is preferable to satisfy the relationship of Ro(590)-Ro(450) ≧ 2 nm at the same time, and more preferably Ro(590)-Ro(450) ≧ 5 nm, which is preferable. It is 10 nm for Ro(590)-Ro(450). Further, Ro (A) means an in-plane hysteresis value measured at a wavelength of Anm.

The angle of the slow axis of the λ/4 film to the transmission axis of the polarizer described later When it is substantially 45° and laminated, a circularly polarizing plate is obtained. The so-called 45° substantially means a range of 30° to 60°, more preferably 40° to 50°. The angle of the slow phase axis in the plane of the λ/4 film and the transmission axis of the polarizer is preferably 41 to 49°, more preferably 42 to 48°, still more preferably 43 to 47°, more preferably 44. ~46°.

The λ/4 film is not particularly limited as long as it is an optically transparent resin, and for example, an acrylic resin, a polycarbonate resin, a cycloolefin resin, a polyester resin, a polylactic acid resin, or a polyvinyl alcohol can be used. A resin, the cellulose resin, or the like. Among them, the λ/4 film is preferably a cellulose resin or a polycarbonate resin from the viewpoint of chemical resistance. Further, from the viewpoint of heat resistance, the λ/4 film is preferably a cellulose resin.

(hysteresis adjuster)

The hysteresis adjustment of λ/4 can be carried out by adding the following hysteresis modifier to the film substrate. As the retardation adjuster, an aromatic compound having two or more aromatic rings as described in the specification of European Patent No. 911,656A2 can be used.

Further, two or more types of aromatic compounds may be used in combination. The aromatic ring of the aromatic compound contains an aromatic hetero ring in addition to the aromatic hydrocarbon ring. Particularly preferred is an aromatic heterocyclic ring, and the aromatic heterocyclic ring is generally an unsaturated heterocyclic ring. Among them, the best is 1,3,5-three ring.

(microparticles)

In the cellulose ester film substrate, in order to improve workability, for example, it is preferred to contain acrylic particles, ceria, titania, alumina, zirconia, calcium carbonate, kaolin, talc, calcined calcium citrate, hydrated citric acid. Inorganic fine particles or crosslinked polymers such as calcium, aluminum citrate, magnesium citrate, calcium phosphate, etc. Matting agent. Further, the acrylic particle system is not particularly limited, but is preferably a multilayer structure acrylic particulate composite. Among these, cerium oxide is preferred in that the haze of the film substrate can be reduced. The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.

(ester compound)

The cellulose ester film substrate preferably contains an ester compound or a sugar ester represented by the following formula (X) from the viewpoint of dimensional stability due to environmental changes. First, the ester compound represented by the formula (X) will be described.

Formula (X) B-(GA)nGB (wherein B represents a hydroxyl group or a carboxylic acid residue, and G represents an alkylene glycol residue having 2 to 12 carbon atoms or an aryl glycol residue having 6 to 12 carbon atoms Or an alkylene oxide diol residue having a carbon number of 4 to 12, and A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms; n is 1 or more. The integer).

In the general formula (X), as the alkanediol component having 2 to 12 carbon atoms, there are ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 1,3-butane. Alcohol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (new Pentanediol), 2,2-diethyl-1,3-propanediol (3,3-dihydroxymethylpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3, 3-dimethylol heptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2 -ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-nonanediol, 1,12-octadecanediol The diol system may be used as one type or a mixture of two or more types. In particular, alkanediol having a carbon number of 2 to 12 is due to cellulose The acetate is excellent in compatibility and is particularly excellent. Examples of the aryl diol component having 6 to 12 carbon atoms include hydroquinone, resorcin, bisphenol A, bisphenol F, and bisphenol. These diols may be used alone or as a mixture of two or more. use.

Further, examples of the alkylene oxide diol component having 4 to 12 carbon atoms include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. These diols can be used as one type or two. More than one kind of mixture is used. Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, sebacic acid, sebacic acid, and dodecane dicarboxylic acid. These may be used alone or in combination of two or more. Examples of the aryldicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalene dicarboxylic acid, and 1,4-naphthalenedicarboxylic acid. Specific examples of the compound represented by the formula (X) (compound X-1 to compound X-17) are shown below, but are not limited thereto.

(sugar ester compound)

Next, a sugar ester compound will be described. The sugar ester compound is an ester other than the cellulose ester, and is a compound obtained by esterifying all or a part of the OH group of a sugar such as a monosaccharide, a disaccharide, a trisaccharide or an oligosaccharide. Examples of the sugar include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, cane tetrasaccharide, 1F-fructose-based canetetraose, stachyose, maltitol, and lactitol. , lactulose, cellobiose, maltose, cellotriose, maltotriose, raffinose and canetriose. Further, gentiobiose, gentian trisaccharide, gentian tetrasaccharide, xylotriose, galactosyl sucrose, and the like can also be mentioned. Among these compounds, a compound having a furanose structure and/or a pyranose structure is particularly preferred. Among these, sucrose, canetriose, canetetraose, 1F-fructose-based canetetraose, stachyose, etc. are preferable, and sucrose is more preferable. Further, as the oligosaccharide, malto-oligosaccharide, isomaltoligosaccharide, oligofructose, oligogalactose, and oligo-xylose are preferably used.

The monocarboxylic acid used for the esterification of the sugar is not particularly limited, and a known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid or the like can be used. The carboxylic acid system to be used may be one type or two or more types. Preferred examples of the aliphatic monocarboxylic acid include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, capric acid, capric acid, and 2-ethyl-hexane carboxylate. Acid, undecanoic acid, dodecanoic acid, tridecanoic acid, endoic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nineteen acid, twenty acid, sassafras acid, tetrakisic acid, Saturated fatty acid, undecylenic acid, oleic acid, sorbic acid, linoleic acid, linoleic acid, arachidonic acid, such as waxy acid, octadecanoic acid, octadecanoic acid, tridecanoic acid, and tridecanoic acid An unsaturated fatty acid such as octenoic acid. Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof. As a comparison Examples of the preferred aromatic monocarboxylic acid include benzoic acid, an aromatic monocarboxylic acid having an alkyl group or an alkoxy group introduced into a benzene ring of benzoic acid, cinnamic acid, diphenyl glycolic acid, and a biphenyl group. An aromatic monocarboxylic acid having two or more benzene rings, such as a carboxylic acid, a naphthalenecarboxylic acid or a tetrahydronaphthalenecarboxylic acid, or a derivative thereof, more specifically, dimethylbenzoic acid, 2, 3 -dimethylbenzoic acid, 3,5-dimethylbenzoic acid, 2,3,4-trimethylbenzoic acid, γ-heodoic acid, ruthenic acid, mesitoic acid, α- Isoduic acid, cumene acid, α-toluic acid, hydrogenated atropic acid, atropic acid, hydrogenated cinnamic acid, salicylic acid, o-, m, p-anisic acid, oleic acid, o-, m , p-high salicylic acid, o-pyroic acid, β-resorcinol, vanillic acid, isovaleric acid, naphthoic acid, o-naphthoic acid, gallic acid, cardioic acid, bitter almond, high Anisic acid, high vanillic acid, homonarufinic acid, o-hyra-naphthoic acid, decanoic acid, p-coumaric acid, particularly preferably benzoic acid. Among the esterified ester compounds, an ethyl fluorenyl compound having an ethyl fluorenyl group introduced through esterification is preferred.

The ester compound or the sugar ester compound represented by the formula (X) is preferably contained in the cellulose acetate film in an amount of 1 to 30% by mass, more preferably 5 to 25% by mass, particularly preferably 5 to 20% by mass. %.

(plasticizer)

The cellulose ester film substrate may also contain a plasticizer if necessary. The plasticizer is not particularly limited, and examples thereof include a polyvalent carboxylate plasticizer, a glycolate plasticizer, a phthalate plasticizer, a phosphate ester plasticizer, and a polyol ester plasticizer. Acrylic plasticizers, etc. Among these, from the viewpoint of easily controlling the cellulose ester film to a hysteresis value to be described later, an acrylic plasticizer is preferable.

The polyol ester-based plasticizer is a plasticizer composed of an ester of a divalent or higher aliphatic polyol and a monocarboxylic acid, preferably having a aryl group. Aroma ring or cycloalkyl ring. More preferably, it is a 2 to 20-valent aliphatic polyol ester.

Further, in the cellulose ester film substrate of the present embodiment, when the plasticizer is contained, it is preferably contained in an amount of 1 to 50% by mass, more preferably 5 to 35% by mass, based on the cellulose acetate. Jia is 5~25% by mass.

(UV absorber)

The cellulose ester film substrate of the present embodiment may contain an ultraviolet absorber. The ultraviolet absorber can improve durability by absorbing ultraviolet rays of 400 nm or less. The ultraviolet absorber is particularly preferably such that the transmittance at a wavelength of 370 nm is 10% or less, and the transmittance is more preferably 5% or less, and particularly preferably 2% or less. Specific examples of the ultraviolet absorber are not particularly limited, and examples thereof include a hydroxydiphenylketone-based compound, a benzotriazole-based compound, a salicylate-based compound, a diphenylketone-based compound, and cyanoacrylic acid. Ester compound, three A compound, a nickel salt-salt compound, an inorganic powder, or the like.

More specifically, for example, 5-chloro-2-(3,5-di-secondbutyl-2-hydroxyphenyl)-2H-benzotriazole, (2-2H-benzotriazole-2-) can be used. -6-(linear and side chain dodecyl)-4-methylphenol, 2-hydroxy-4-benzyloxydiphenyl ketone, 2,4-benzyloxydiphenyl ketone, and the like. Commercially available products can also be used. For example, Tinuvin such as Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, etc., manufactured by BASF Japan Co., Ltd., is preferably used.

The preferred ultraviolet absorbers are benzotriazole-based UV absorbers, diphenylketone-based UV absorbers, and three It is a UV absorber, and is preferably a benzotriazole-based ultraviolet absorber or a diphenylketone-based ultraviolet absorber. In addition, there are 1, 3, 5 three A discotic compound such as a cyclic compound is also preferably used as an ultraviolet absorber. Further, as the ultraviolet absorber, a polymer ultraviolet absorber can be preferably used, and a polymer type ultraviolet absorber is particularly preferably used.

As the benzotriazole-based ultraviolet absorber, TINUVIN 109 (octyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-) manufactured by BASF Japan Co., Ltd., which is a commercially available product, can be used. Benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole- a mixture of 2-yl)phenyl]propionates), TINUVIN 928 (2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4- (1,1,3,3-tetramethylbutyl)phenol) and the like. As three For the ultraviolet absorber, TINUVIN 400 (2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-three, manufactured by BASF Japan), which is commercially available, can be used. -2-yl)-5-hydroxyphenyl and oxoxane reaction product), TINUVIN 460 (2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4- Dibutoxyphenyl)-1,3-5-three ), TINUVIN 405 (2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-three A reaction product with (2-ethylhexyl)-glycidyl ester) and the like.

The ultraviolet absorber may be added by dissolving the ultraviolet absorber in an alcohol such as methanol, ethanol or butanol or an organic solvent such as dichloromethane, methyl acetate, acetone or dioxolane or a mixed solvent thereof. It is added to the resin solution (coating liquid) which becomes a film base material, or is added directly to the coating liquid composition. If the inorganic powder is not dissolved in the organic solvent, it is added to the coating liquid by dispersing it in an organic solvent and cellulose acetate using a dissolver or a sand mill.

The amount of the ultraviolet absorber to be used is preferably from 0.5 to 10% by mass, more preferably from 0.6 to 4% by mass, based on the cellulose acetate film.

(Antioxidants)

The cellulose ester film substrate of the present embodiment may further contain an antioxidant (anti-deterioration agent). The antioxidant has a function of delaying or preventing decomposition of the cellulose acetate film due to halogen or a phosphate of a phosphate-based plasticizer due to a residual solvent amount in the cellulose acetate film. As the antioxidant, a hindered phenol-based compound is preferably used, and examples thereof include 2,6-di-t-butyl-p-cresol and pentaerythritol 肆[3-(3,5-di-t-butyl-4-hydroxybenzene). Propionate], triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-double [ 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di Tributylanilino)-1,3,5-three , 2,2-thio-di-extended ethyl bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di Third butyl-4-hydroxyphenyl)propionate, N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-phenylpropanamide), 1,3, 5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-t-butyl-4-hydroxybenzyl) - Iso-isocyanurate or the like. The amount of such compounds added is preferably from 1 ppm to 10,000 ppm, more preferably from 10 to 1,000 ppm, based on the mass ratio of the cellulose acetate film.

(disadvantage)

The cellulose ester film substrate has a defect of 5 μm or more in diameter, and is preferably 1/10 cm square or less. More preferably, it is 0.5 /10 cm square or less, and particularly preferably 0.1 /10 cm square. The diameter of the defect here is a diameter when the defect is a circle, and when it is not a circle, it is determined by a microscope to observe the range of the defect as the maximum diameter (the diameter of the circumscribed circle).

When the disadvantage is a bubble or a foreign object, the scope of the defect is micro The size of the shadow when observing the shortcomings of the transmitted light of the interference microscope. When the disadvantage is that the surface shape of the roller, such as transfer or scratch, changes, the shortcoming of the interference light of the interference microscope can be observed to confirm the size.

When the number of the defects is more than one /10 cm square, for example, when a tension is applied to the film during processing in the subsequent step, the film may be broken due to the defect, and the productivity may be lowered. In addition, when the diameter of the defect is 5 μm or more, it can be visually confirmed by observation of a polarizing plate or the like, and a bright spot may occur when used as an optical member.

Moreover, even if it is not visually confirmed, when a hardened layer is formed, the coating film may not be formed uniformly, and it may become a fault (drag-coating). The disadvantages referred to herein are voids in the film (foaming defects) which occur due to rapid evaporation of the solvent in the drying step of the solution film formation, or foreign matter in the film forming solution or foreign matter mixed in the film formation. The foreign matter in the film (foreign defect). Further, in the measurement of the cellulose ester film substrate according to JIS-K7127-1999, the elongation at break in at least one direction is preferably 10% or more, and more preferably 20% or more. The upper limit of the elongation at break is not particularly limited, but is actually about 250%. In order to increase the elongation at break, it is effective to suppress the defects in the film due to foreign matter or foaming.

(optical properties)

The cellulose ester film substrate preferably has a total light transmittance of 90% or more, more preferably 92% or more. Moreover, the upper limit in reality is about 99%. The haze value is preferably 2% or less, more preferably 1.5% or less. The total light transmittance and the haze value can be measured in accordance with JIS K7361 and JIS K7136.

Further, the in-plane hysteresis value Ro of the cellulose ester film substrate is preferably 0 to 5 nm, and the hysteresis value Rth in the thickness direction is preferably in the range of -10 to 10 nm. Further, Rth is preferably in the range of -5 to 5 nm. Or, hysteresis value Ro is preferably in the range of 30 to 200 nm, more preferably in the range of 30 to 90 nm. The hysteresis value Rth in the thickness direction is preferably in the range of 70 to 300 nm.

The in-plane retardation Ro value is defined by the following formula (I), and the hysteresis value Rth in the thickness direction is defined by the following formula (II).

Formula (I) Ro=(nx-ny)×d

Formula (II) Rth={(nx+ny)/2-nz}×d (wherein nx represents the refractive index in the direction of the slow axis in the plane of the film substrate, and ny represents the in-plane and late in the film substrate) The refractive index in the direction orthogonal to the phase axis, nz represents the refractive index in the thickness direction of the film substrate, and d represents the thickness (nm) of the film substrate.

The hysteresis can be obtained, for example, by using KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) at a wavelength of 590 nm in an environment of 23 ° C and 55% RH (relative humidity).

[Film of cellulose ester film]

Next, an example of a film forming method of a cellulose ester film as an example of a film substrate will be described, but the film forming method is not limited thereto. As a film forming method of the cellulose ester film, a production method such as an inflation method, a T-die method, a calendering method, a cutting method, a casting method, an emulsification method, or a hot pressing method can be used.

(Organic solvents)

When the cellulose ester film is produced by the solution casting film forming method described later, the organic solvent suitable for forming the resin solution (coating liquid composition) can be used without limitation as long as the cellulose ester resin or other additives are simultaneously dissolved. . For example, examples of the chlorine-based organic solvent include dichloromethane, and examples of the non-chlorine-based organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, and 1,3-dioxolane. 1,4-two Alkane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1, 1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3 , 3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, n-propanol, isopropanol, n-butanol, second butanol, third butanol, etc., preferably dichloromethane , methyl acetate, ethyl acetate, acetone. It is preferred that the solvent is a coating liquid composition obtained by dissolving a total of 15 to 45% by mass of a cellulose ester resin and other additives.

(solution casting film forming method)

In the solution casting film forming method, the step of preparing a coating liquid by dissolving a resin and an additive in a solvent, and casting the coating liquid onto a metal support having a strip shape or a roll shape, is carried out by the following steps: The step of making the cast coating liquid into a web, drying, stripping from the metal support, stretching or width maintaining, and further drying the step of winding the finished cellulose ester film.

As the metal support, it is preferable to use a stainless steel belt or a drum which is plated by a casting.

The casting (casting) width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to be -50 ° C to a temperature at which the solvent does not foam. Since the higher the temperature, the drying speed of the net is faster and better, but if it is too high, the net will foam and the flatness will be deteriorated.

The preferred support temperature is suitably determined at 0 to 100 ° C, more preferably 5 to 30 ° C. Alternatively, it is also preferred to gel the web by cooling and peel it off from the roll in a state containing a large amount of residual solvent. The method of controlling the temperature of the metal support is not particularly limited, and there is a method of blowing warm air or cold air, or a method of bringing warm water into contact with the back side of the metal support. In the case of using warm water, it is preferable that the temperature of the metal support is short before the fixation is performed because the heat is efficiently transmitted.

When using warm air, consider the case where the temperature of the net is lowered due to the latent heat of evaporation of the solvent, and the temperature of the temperature is higher than the temperature of the target, and the temperature is higher than the temperature of the target. .

In particular, it is preferable to change the temperature of the support and the temperature of the dry air from the time of self-flowing to peeling, and to dry efficiently.

In order to obtain good planarity, the amount of residual solvent in the cellulose ester film when the web is peeled off from the metal support is preferably from 10 to 150% by mass, more preferably from 20 to 40% by mass or from 60 to 130% by mass, particularly preferably from 20% by weight. ~30% by mass or 70~120% by mass. The amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(M - N) / N} × 100

Further, the M system collects the mass of the sample of the net or the film at any time during or after the production, and the N is the mass of the mass M after heating at 115 ° C for 1 hour.

In the thin drying step of the cellulose ester, the mesh is peeled off from the metal support and dried, and the amount of the residual solvent is preferably 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0% to 0.01% by mass or less. .

In the film drying step, a roll drying method (a plurality of rolls arranged in the upper and lower sides is used to alternately pass the net and dried) or a method of drying the net side by a tenter method is generally employed.

In the stretching step, the film may be successively or simultaneously extended in the longitudinal direction (MD direction) and the width direction (TD direction) of the film. The stretching ratios of the two orthogonal directions orthogonal to each other are preferably 1.0 to 2.0 times in the MD direction, 1.05 to 2.0 times in the TD direction, and 1.0 to 1.5 times in the MD direction. The TD direction is performed in the range of 1.05 to 2.0 times. For example, it can be mentioned that the peripheral speed is given to a plurality of rollers. A method in which the difference in the direction of the MD is used to extend the MD in the MD direction by means of a clamp or a needle fixing the both ends of the net, and the distance between the jig and the needle is enlarged in the advancing direction, and the method of extending in the MD direction is similarly The method of extending in the TD direction, or expanding the MD direction and the TD direction at the same time, and extending in both directions.

The width retention or extension of the width of the film forming step is preferably carried out by a tenter, and may be a pin tenter or a clip tenter.

The film transport tension in the film forming step, such as a tenter, is preferably 120 to 200 N/m, more preferably 140 to 200 N/m, and most preferably 140 to 160 N/m, although it depends on the temperature.

When the glass transition temperature of the cellulose ester film is Tg, the temperature at the time of stretching is (Tg-30) to (Tg+100) ° C, preferably (Tg-20) to (Tg + 80) ° C, more preferably (Tg-5)~(Tg+20) °C.

The Tg of the cellulose ester film can be controlled by the kind of the material constituting the film and the ratio of the constituent materials. The Tg at the time of drying the cellulose ester film is preferably 110 ° C or higher, more preferably 120 ° C or higher, and particularly preferably 150 ° C or higher. The glass transition temperature is preferably 190 ° C or lower, more preferably 170 ° C or lower. The Tg system of the cellulose ester film can be obtained by the method described in JIS K7121. When the temperature at the time of stretching is 150 ° C or more and the stretching ratio is 1.15 times or more, the surface is preferably coarsened. By roughening the surface of the cellulose ester film, it is preferable because the slip property is increased and the surface processability is increased.

(melt casting film forming method)

The cellulose ester film substrate can also be formed by a melt casting film forming method. Melt casting film forming method means containing cellulose ester resin, plasticizer, etc. The composition of the additive is heated and melted to a temperature at which fluidity is exhibited, and then the fluidized cellulose ester-containing melt is cast.

In the melt casting film forming method, from the viewpoint of mechanical strength, surface precision, and the like, a melt extrusion method is preferred. The plurality of raw materials used for melt extrusion are generally preferably granulated by pre-kneading.

The granulation system can be supplied to the extruder by a well-known method, for example, a dry cellulose ester or a plasticizer or other additives can be supplied to the extruder using a 1-axis or 2-axis extruder, and extruded from the die. Stranded, water cooled or air cooled for cutting.

The additives may be mixed prior to being supplied to the extruder, or may be supplied by separate feeders.

A small amount of additives such as particles or an antioxidant are preferably mixed in advance in order to uniformly mix.

The extruder preferably suppresses the shearing force and processes the resin at a low temperature as much as possible in such a manner that the resin does not deteriorate (molecular weight reduction, coloration, gel formation, etc.). For example, in the case of a 2-axis extruder, it is preferred to use a deep groove type screw to rotate in the same direction. From the standpoint of the uniformity of the kneading, the type of engagement is preferred.

Film formation was carried out using the pellets obtained as described above. Needless to say, the powder of the raw material may be directly supplied to the extruder by the feeder without granulation, and the film formation may be carried out in that manner.

For the above-mentioned pellets, a 1-axis or 2-axis type extruder is used, and the melting temperature at the time of extrusion is set to about 200 to 300 ° C, and the foreign matter is removed by filtration using a leaf disc type filter or the like, and then cast from the T die. In the form of a film, a film was sandwiched between a cooling roll and an elastic contact roll, and a cellulose ester film was produced by curing on a cooling roll.

When it is introduced into the extruder from the supply hopper, it is preferably true Under vacant or reduced pressure or in an inert atmosphere, prevent oxidative decomposition and the like.

The extrusion flow rate is preferably adjusted stably by introduction of a gear pump or the like. Further, in the filter for removing foreign matter, a stainless steel fiber sintered filter is used in comparison. The stainless steel fiber sintered filter is obtained by compressing the stainless steel fiber body in a complicated entangled state, and compressing the contact portion to form an integrated one. The density is changed by the thickness and the amount of compression of the fiber, and the filtration precision can be adjusted.

Additives such as plasticizers or particles may be mixed with the resin in advance or may be mixed in the middle of the extruder. For uniform addition, it is preferred to use a mixing device such as a static mixer.

The temperature of the cellulose ester film on the touch roller side when the cellulose ester film is sandwiched between the cooling roll and the elastic contact roll is preferably not more than Tg (Tg + 110 ° C) of the film. For the roller having an elastomer surface used for such a purpose, a well-known roller can be used.

The elastic contact roller is also referred to as a pinch rotating body. As the elastic contact roller, a commercially available person can also be used.

When the cellulose ester film is peeled off from the cooling roll, it is preferred to control the tension to prevent deformation of the film.

Further, the cellulose ester film obtained as described above is preferably extended by the stretching operation after the step of contacting the cooling roll.

As the stretching method, a well-known roll stretching machine or tenter or the like can be preferably used. The stretching temperature is generally preferably carried out in a temperature range of Tg to (Tg + 60) °C of the resin constituting the film.

Before the winding, the end portion of the product is cut at the width of the product, and in order to prevent sticking or scratching during winding, knurling (embossing) may be applied to both ends. The method of knurling can be used on the side A metal ring having a concave-convex pattern is processed by heating or pressurization. The grip portion of the jig at both ends of the film is usually cut off and reused because the cellulose ester film is deformed and cannot be used as a product.

(Method of manufacturing obliquely stretched film)

The λ/4 film system can be produced by a method of producing a diagonally stretched film. As a method for producing the obliquely stretched film, it is possible to produce a stretched film having a slow phase axis at an angle of more than 0° and less than 90° with respect to the direction in which the film is elongated. As the unstretched film before oblique stretching, the aforementioned cellulose ester film can be used.

Here, the angle with respect to the direction in which the film extends is the angle in the plane of the film. Since the retardation axis is generally exhibited in the extending direction or in a direction perpendicular to the extending direction, the retardation axis can be manufactured by extending at an angle of more than 0° and less than 90° with respect to the extending direction of the film. Extended film.

The angle between the extension direction of the film and the slow axis (alignment angle θ) can be arbitrarily set to a desired angle in a range exceeding 0° and not exceeding 90°, but preferably 10° to 80°. More preferably, it is 40°~50°.

(oblique extension)

The obliquely stretched film can be produced using a diagonal stretching device (oblique stretch tenter). As the obliquely extending tenter, the alignment angle of the film can be set freely by changing the pattern of the guide rail, and the alignment axis of the film can be preferably used with high precision in the film width direction. A device that is aligning and capable of controlling film thickness or hysteresis with high precision.

(physical properties of cellulose ester film substrate)

The film thickness of the cellulose ester film substrate is preferably 5 to 200 μm, more preferably 5 to 80 μm, and particularly preferably 5 to 34 μm. The effect of the present embodiment can be more easily exhibited by forming the cured layer of the present embodiment on the cellulose ester film substrate of the film. Further, the length of the cellulose ester film substrate is preferably from 500 to 10,000 m, more preferably from 1,000 to 8,000 m. By the range of the above length, the hardened layer or the like is excellent in handleability of coating or handling property of the cellulose ester film substrate itself.

Further, the arithmetic mean roughness Ra of the cellulose ester film substrate is preferably from 2 to 10 nm, more preferably from 2 to 5 nm. The arithmetic mean roughness Ra can be measured in accordance with JIS B0601:1994.

[other layers]

In the optical film of the present embodiment, another layer such as an antireflection layer or a conductive layer may be provided.

(anti-reflection layer)

In the optical film of the present embodiment, an antireflection layer can be applied to the cured layer as an antireflection film having an external light reflection preventing function.

The antireflection layer is preferably laminated by reducing the reflectance by optical interference, considering the refractive index, the film thickness, the number of layers, the layer order, and the like. The antireflection layer is preferably a low refractive index layer having a lower refractive index than the protective film of the support or a high refractive index layer and a low refractive index layer having a higher refractive index than the protective film of the support.

<low refractive index layer>

The low refractive index layer preferably contains ceria-based fine particles, and its refractive index is measured at 23 ° C and a wavelength of 550 nm, preferably in the range of 1.30 to 1.45.

The film thickness of the low refractive index layer is preferably in the range of 5 nm to 0.5 μm, more preferably in the range of 10 nm to 0.3 μm, and most preferably in the range of 30 nm to 0.2 μm.

In the composition for forming a low refractive index layer, as the ceria-based fine particles, it is particularly preferable to contain at least one type of particles having an outer shell layer and having a porous or void inside. In particular, the particles having an outer shell layer and having a porous or hollow interior are preferably hollow ceria-based fine particles.

In addition, the composition for forming a low refractive index layer may be contained in an organic hydrazine compound represented by the following formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.

General formula (Osi-1): Si(OR) ₄

In the formula, R represents an alkyl group having 1 to 4 carbon atoms. As the organic ruthenium compound represented by the formula, specifically, tetramethoxy decane, tetraethoxy decane, tetraisopropoxy decane or the like is preferably used.

Further, in the composition for forming a low refractive index layer, the fluorine-containing compound containing a fluorine atom in a range of from 35 to 80% by mass and containing a crosslinkable or polymerizable functional group may be used as a thermosetting property. And/or photohardenable compounds. Specifically, it is a fluorine-containing polymer or a fluorine-containing sol-gel compound or the like. As the fluoropolymer, for example, a hydrolyzate or a dehydrated condensate of a decane compound containing a perfluoroalkyl group [for example, (heptadecafluoro-1,1,2,2-tetrahydroindenyl)triethoxydecane], A fluorine-containing copolymer containing a fluorine-containing monomer unit and a crosslinking reactive unit as a constituent unit may also be mentioned. Further, a solvent, an optional decane coupling agent, a curing agent, a surfactant, or the like may be added to the composition for forming a low refractive index layer.

<High refractive index layer>

In the high refractive index layer, it is preferably measured at 23 ° C and a wavelength of 550 nm. In order to adjust the refractive index to the range of 1.4 to 2.2. Further, the thickness of the high refractive index layer is preferably from 5 nm to 1 μm, more preferably from 10 nm to 0.2 μm, most preferably from 30 nm to 0.1 μm. The adjustment of the refractive index can be achieved by adding metal oxide fine particles or the like. Further, the refractive index of the metal oxide fine particles used is preferably from 1.80 to 2.60, more preferably from 1.85 to 2.50.

The type of the metal oxide fine particles is not particularly limited, and may be used from Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and A metal oxide of at least one element selected from S.

<Electrically conductive layer>

In the optical film, a conductive layer may also be formed on the hardened layer. As the conductive layer to be provided, a conductive material which is generally widely known can be used. For example, a metal oxide such as indium oxide, tin oxide, indium tin oxide, gold, silver, palladium or the like can be used. These can be formed as a film on an optical film by a vacuum vapor deposition method, a sputtering method, an ion plating method, a solution coating method, or the like. Further, an organic conductive material may be used as the π-conjugated conductive polymer to form a conductive layer.

In particular, a conductive material containing, as a main component, any of indium oxide, tin oxide, or indium tin oxide which is excellent in transparency and conductivity and which is obtained at a relatively low cost can be preferably used. Since the thickness of the conductive layer differs depending on the material to be used, it cannot be generalized, but it is 1000 Ω or less, preferably 500 Ω or less in terms of surface resistivity, and if it is economical, it is preferably 10 nm or more. It is preferably 20 nm or more and 80 nm or less, more preferably 70 nm or less. In such a film, interference fringes of visible light caused by uneven thickness of the conductive layer are less likely to occur.

[Polarizer]

Next, a polarizing plate using the optical film of the present embodiment will be described. The polarizing plate can be produced by a general method. For example, it is preferred to subject the optical film to alkali saponification, and to immerse the treated optical film in an iodine solution, and to use a completely saponified polyvinyl alcohol on one side of the produced polarizing film (polarizer). The aqueous solution is applied.

The optical film may be bonded to the other surface of the polarizer, or the cellulose ester film substrate or the like may be bonded. The film thickness of the film substrate bonded to the other surface is preferably in the range of 5 to 100 μm from the viewpoint of adjusting the smoothness and the curl balance and further improving the anti-winding offset effect, and more preferably Range of 5~34μm.

The polarizing film which is a main component of a polarizing plate is an element which passes only the light of a polarizing surface in a certain direction, and the polarizing film currently known is a polyvinyl alcohol type polarizing film. Among the above polarizing films, those which dye iodine-based polyvinyl alcohol-based films and dyed dichroic dyes are not limited thereto.

The polarizing film is formed by forming a film of a polyvinyl alcohol aqueous solution, stretching it after stretching on one axis, or performing one-axis stretching after dyeing, preferably by using a boron compound for durability treatment. The film thickness of the polarizing film is 5 to 30 μm, preferably 8 to 15 μm.

A polarizing plate was formed by laminating one surface of the optical film of the present embodiment on the surface of the polarizing film. It is preferable to bond by a water-based adhesive which completely saponifies polyvinyl alcohol or the like as a main component.

(circular polarizer)

An optical film can also be used to form a circular polarizing plate. Further, a polarizing plate protective film, a polarizing mirror, and a λ/4 film may be laminated in this order to form a circularly polarizing plate. at this time, The angle between the slow axis of the λ/4 film and the absorption axis (or transmission axis) of the polarizing film was 45°. The long strip-shaped polarizing plate protective film, the long strip-shaped polarizing mirror, and the long strip-shaped λ/4 film (long obliquely extending film) are preferably formed by laminating in this order.

The circularly polarizing plate is produced by using a polyvinyl alcohol coated with iodine or a dichroic dye as a polarizer, and can be bonded by a λ/4 film/polarizer. The film thickness of the polarizer is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

A circular polarizing plate can be produced by a general method. In other words, it is preferred that the polyvinyl alcohol-based film is immersed and stretched in an iodine solution, and a completely saponified polyvinyl alcohol aqueous solution is applied to the surface of the polarizer to be produced, and the alkali-saponified λ/4 is bonded thereto. membrane.

[adhesive layer]

In order to fit the substrate of the liquid crystal cell and the polarizing plate, the adhesive layer on one side of the film for the polarizing plate is not necessarily optically transparent, and is preferably one which exhibits moderate viscoelasticity or adhesion characteristics.

As the specific adhesive layer, for example, an acrylic copolymer, an epoxy resin, a polyurethane, a oxime polymer, a polyether, a butyral resin, a polyamine resin, or a polyvinyl alcohol can be used. A polymer such as an adhesive such as a resin or a synthetic rubber or an adhesive is formed into a film by a drying method, a chemical curing method, a thermosetting method, a hot melt method, a photo-curing method, or the like to be cured. Among them, the acrylic copolymer is most suitable for controlling the adhesiveness, and is excellent in transparency, weather resistance, durability, and the like, and can be preferably used.

[Image display device]

The optical film of the present embodiment is preferably used in an image display device to exhibit performance excellent in visibility. As an image display Examples of the display device include a reflective type, a transmissive type, and a semi-transmissive liquid crystal display device, or a liquid crystal display device of various driving methods such as a TN type, an STN type, an OCB type, a VA type, an IPS type, and an ECB type, and an organic EL display. Device or plasma display, etc. Among these image display devices, the liquid crystal display device is preferably excellent in high visibility.

A protective portion may be disposed on the more visible side of the hardened layer of the optical film of the side polarizing plate. This protection unit can be constructed with a front panel or a touch panel. The protective portion is bonded to the hardened layer by a filler (photocurable resin) for filling a space between the hardened layer and the hardened layer. The front panel of the protective portion is not particularly limited, and a known person such as an acrylic plate or a glass plate can be used. Further, the material and thickness of the front panel can be appropriately selected in accordance with the use of the image display device.

The filler is preferably a solvent-free filler, and examples of the commercially available product include SVR1120, SVR1150, and SVR1320 (above, manufactured by DESEMIAALS CORPORATION), or HRJ-60, HRJ-302, and HRJ-53 (above). , Xie Li Chemical Industry Co., Ltd.) and so on. When a filler is used, one type may be used alone or a plurality of types may be used in combination.

The bonding of the optical film to the front panel can be performed, for example, as follows. First, prepare a filler. Then, a filler is applied onto the surface of the hardened layer of the optical film, and the front panel is laminated on the coating film of the filler. In this state, the filler is cured by light irradiation or the like, and the optical film and the front panel are bonded together. When the filler is applied to the surface of the hardened layer, the surface free energy of the hardened layer is 30 mN/m or more, and the filler is not repelled at the end of the hardened layer, and the state of uniform expansion is maintained, thereby obtaining visibility. Excellent image display device.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the invention is not limited thereto. In addition, in the embodiment, the expression "part" or "%" is used, but unless otherwise specified, it means "mass portion" or "mass%".

<Example 1> [Production of cellulose ester film 1] <Modulation of cerium oxide dispersion>

After stirring for 30 minutes with a dissolver, the mixture was dispersed by a homogenizer (Manton Gaulin). 88 parts by mass of dichloromethane was added to the cerium oxide dispersion while stirring, and the mixture was stirred and mixed for 30 minutes in a dissolver to prepare a cerium oxide dispersion diluent. Filtration was carried out using a fine particle dispersion diluent filter (ADVANTEC Toyo: polypropylene wound cartridge filter TCW-PPS-1N).

<Modulation of Coating Composition 1> (cellulose ester resin)

Cellulose triacetate A (cellulose triacetate synthesized from seed cotton, acetyl group substitution degree 2.88, Mn = 140000) 90 parts by mass

(additive)

(UV absorber)

TINUVIN 928 (BASF Japan Co., Ltd.) 3 parts by mass

(microparticles)

Ceria dispersing diluent 4 parts by mass

(solvent)

The above-mentioned liquid was poured into a sealed container, heated, and completely dissolved by stirring, and filtered using a filter paper No. 24 made of a filter paper (package) to prepare a coating liquid (coating liquid composition 1).

Next, a belt casting device was used to uniformly cast on the stainless steel belt support. The solvent was evaporated on the stainless steel belt support until the residual solvent amount became 100% by mass, and peeled off from the stainless steel belt support. The web of the cellulose ester film was evaporated at 35 ° C, cut into a width of 1.15 m, and stretched 1.15 times in a TD direction (width direction of the film) by a tenter, and dried at a drying temperature of 140 ° C. Then, it was dried by a plurality of rolls in a drying apparatus at 120 ° C for 15 minutes, and then cut into a width of 1.3 m, and a knurling process of a width of 10 mm and a height of 5 μm was applied to both ends of the film, and wound up in a core. Above, a cellulose ester film 1 was obtained. The cellulose ester film 1 had a film thickness of 15 μm and a roll length of 3,900 m.

Further, the stretching ratio in the MD direction calculated from the rotation speed of the stainless steel belt support and the operation speed of the tenter was 1.01 times.

[Production of Optical Film 1]

On the A side of the cellulose ester film 1 produced above (the surface not contacting the casting tape), the following hardened layer composition 1 was applied by using an extrusion coater, and the drying zone temperature was 50 ° C at a constant rate. After drying in a drying zone at a temperature of 50 ° C, the illuminance of the irradiated portion was 100 mW/cm ² and the irradiation amount was 0.25 J/cm ² while applying an ultraviolet lamp to an atmosphere having an oxygen concentration of 1.0% by volume or less. The layer was hardened to form a hardened layer 1 having a dry film thickness of 5 μm, and wound into a roll to form an optical film 1.

Hardened Layer Composition 1 <Composition of hardened layer composition 1> (active wire hardening resin)

NK Ester A-DCP (tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 92 parts by mass

(photopolymerization initiator)

Irgacure 184 (BASF Japan Co., Ltd.) 5 parts by mass

(additive)

Oxide compound (BYK Chemical Japan Co., Ltd.: BYK-UV3510) 1 part by mass

(cyclic organic compounds)

B-1 (YS Polyster NH, manufactured by YASUHARA CHEMICAL CO., LTD.) 8 parts by mass

(solvent)

Propylene glycol monomethyl ether 10 parts by mass Methyl ethyl ketone 90 parts by mass

[Production of Optical Film 2]

The optical film 2 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-2. Further, the synthesis method of the cyclic organic compound B-2 is as follows.

(Synthesis method of B-2)

2170 parts by mass of 4-n-octylstyrene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2450 parts by mass of pure water, 50 parts by mass of calcium phosphate 50 parts by mass, and 50 ppm of dodecylbenzene were placed in an autoclave equipped with a stirrer. 2.8 parts by mass of sulfonate, 166 parts by mass of benzamidine peroxide, 25 parts by mass of t-butyl peroxyisopropyl carbonate, and 135 parts by mass of α-methylstyrene dimer. Next, the mixture was uniformly stirred at room temperature and at a number of revolutions of 1000 rpm for 1 hour using a stirrer to form a mixed solution.

Next, the obtained mixed solution was heated, and the temperature in the autoclave was raised from a temperature of about 30 ° C to a temperature of 10 ° C / min to 90 ° C. Then, as the step (A), the temperature in the autoclave was maintained at a temperature of 90 ° C, and initial polymerization was carried out for 1 hour.

Subsequently, the temperature in the autoclave was raised from 90 ° C to a temperature of 10 ° C / min, and the temperature was raised to 120 ° C. Then, as the step (B), the temperature in the autoclave was maintained at a temperature of 120 ° C, and suspension polymerization was carried out for 5 hours to obtain a polymer (organocyclic compound B-2).

[Production of Optical Film 3]

The optical film 3 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-3. again The synthesis method of the cyclic organic compound B-3 is as follows.

(Synthesis method of B-3)

2170 parts by mass of 4-methylstyrene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2450 parts by mass of pure water, 50 parts by mass of calcium phosphate 50 parts by mass, and 50 ppm of dodecylbenzenesulfonate were respectively placed in an autoclave equipped with a stirrer. 2.8 parts by mass of the acid salt, 166 parts by mass of benzamidine peroxide, 25 parts by mass of t-butyl peroxyisopropyl carbonate, and 135 parts by mass of α-methylstyrene dimer. Next, under the same conditions as the synthesis method of the cyclic organic compound B-2, a mixed solution is prepared, and further suspension polymerization of the steps (A) and (B) is carried out to obtain a polymer (cyclic organic compound B- 3).

[Production of Optical Film 4]

The optical film 4 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-4 (YS Resin TO105, manufactured by YASUHARA Chemical Co., Ltd.).

[Production of Optical Film 5]

The optical film 5 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-5 (Nittoresin Coumarone V-120S, manufactured by Nikkei Chemical Co., Ltd.).

[Production of Optical Film 6]

The optical film 6 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound C-1. Further, the synthesis method of the cyclic organic compound C-1 is as follows.

(Synthesis method of C-1)

A styrene-butadiene copolymer as a rubbery elastomer was dissolved in a mixture of 50 parts by mass of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 50 parts by mass of methyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.). (The styrene content is 25%, manufactured by Asahi Kasei Kogyo Co., Ltd., trade name Tufdene 2000A) 4.0 parts by mass and 5.0 parts by mass of ethylbenzene to form a raw material solution. As a polymerization initiator, 1 part by mass of an ethylbenzene solution of azobisisobutyronitrile was prepared.

Next, the raw material solution was supplied at a rate of 5.0 L/hour in a complete mixing tank having an internal volume of 20 L of the double-spiral stirring blade, and the ethylbenzene solution of the initiator was supplied at a rate of 0.1 L/hour at 110 ° C. The polymerization was carried out under the conditions of a stirring speed of 120 rpm. Next, the polymerization reaction liquid which has passed through the complete mixing tank is continuously introduced into a tubular reactor having a content of 30 L, which is connected to the complete mixing tank and has a static mixer inside, and the reaction at the outlet of the reactor The polymerization was carried out under the conditions that the liquid temperature was 150 °C. The obtained polymerization reaction liquid was continuously supplied to a devolatilization apparatus made of a flash drum having a heater, and a volatile component such as an unreacted monomer or solvent was separated under the conditions of a temperature of 220 ° C and a pressure of 665 Pa. Polymer (cyclic organic compound C-1). The content of the styrene structural unit in the polymer was 50% by mass, and the content of the methyl acrylate structural unit was 50% by mass. For reference, the structural formula of the cyclic organic compound C-1 is shown below.

[Production of Optical Film 7]

The optical film 7 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound C-2. Further, the synthesis method of the cyclic organic compound C-2 is as follows.

(Synthesis method of C-2)

After using a 2-liter four-necked flask equipped with a thermometer, a stirring device, a dropping funnel, and a cooling tube, 800 parts by mass of toluene (water: adjusted to 900 ppm) and 6.0 parts by mass of boron trifluoride gas as a catalyst were added. While stirring at a temperature of 60 ° C, 160 parts by mass of α-pinene (manufactured by YASUHARA CHEMICAL Co., Ltd.) and 160 parts by mass of β-pinene (manufactured by YASUHARA Chemical Co., Ltd.) and d-limonene were dropped for 3 hours. 160 parts by mass of a mixture of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) in an amount of 32 parts by mass, and then stirred for 1 hour and allowed to react.

Next, after washing the mixed solution with water to remove the catalyst, the toluene and the unreacted monomer and the low molecular weight compound were distilled off by distillation at a maximum temperature of 200 ° C under a reduced pressure of 10 mmHg to obtain a polymer (circular type). Organic compound C-2). The content of the terpene structural unit in the polymer is 90% by mass, and the content of the styrene structural unit is 10% by mass. %. For reference, the structural formula of the cyclic organic compound C-2 is shown below.

[Production of Optical Film 8]

The optical film 8 was produced in the same manner as in the production of the optical film 1 except that the organic compound B-1 was changed to the organic compound C-3 (Dianal BR88, manufactured by Mitsubishi Rayon Co., Ltd.). Further, the organic compound C-3 does not have an aromatic ring structure, and does not have a structure having a polar substituent in the alicyclic structure. For reference, the structural formula of the organic compound C-3 is shown below.

[Production of Optical Film 9]

In addition to changing the cyclic organic compound B-1 to a cyclic organic compound C-4 (biphenyl, manufactured by Tokyo Chemical Industry Co., Ltd.), The optical film 9 was produced in the same manner as in the production of the film 1. For reference, the structural formula of the cyclic organic compound C-4 is shown below.

[Production of Polarizing Plate 101]

The optical film 1 was attached to the surface of one side of the polarizing film, and KC4UZ (manufactured by Konica-Minolta Co., Ltd.), an optical film of a commercial product, was attached to the other side of the polarizing film to prepare a polarizing plate 101. More details are as follows.

(a) Production of polarizing film

When 100 parts by mass of polyvinyl alcohol (hereinafter referred to as PVA) having a degree of saponification of 99.95 mol% and a degree of polymerization of 2400 is impregnated with 10 parts by mass of glycerin and 170 parts by mass of water, the mixture is melted and kneaded, and after defoaming, from the T die. The film was formed by melt extrusion onto a metal roll. Then, it was dried and heat-treated to obtain a PVA film. The obtained PVA film system had an average thickness of 15 μm, a water content of 2.4%, and a film width of 3 m.

Next, the obtained PVA film was continuously treated in the order of one-axis stretching, fixing treatment, drying, and heat treatment in a preliminary swelling, dyeing, and wet method to prepare a polarizing film. Specifically, the PVA film was immersed in water at a temperature of 30 ° C for 30 seconds to prepare for swelling, and immersed in an aqueous solution having an iodine concentration of 0.4 g/liter and a potassium iodide concentration of 40 g/liter at a temperature of 35 ° C for 3 minutes. Thereafter, in a 50 ° C aqueous solution having a boric acid concentration of 4%, a tension of 700 N/m was applied to the film, and a 1-fold axial extension was carried out at a concentration of potassium iodide. The solution was immersed for 5 minutes in an aqueous solution of 40 g/liter, boric acid concentration of 40 g/liter, and zinc chloride concentration of 10 g/liter at a temperature of 30 ° C for 5 minutes. Then, the PVA film was taken out, dried by hot air at a temperature of 40 ° C, and further heat-treated at a temperature of 100 ° C for 5 minutes. The obtained polarizing film had an average thickness of 5 μm, a polarizing performance of 43.0%, a degree of polarization of 99.5%, and a 2-color ratio of 40.1.

(b) Production of polarizing plate

Follow the steps 1 to 5 below to make a polarizing plate.

Step 1: The aforementioned polarizing film was immersed in a storage tank of a 2% by mass solid polyvinyl alcohol adhesive solution for 1 to 2 seconds.

Step 2: For the optical film 1 and KC4UZ, alkali saponification treatment was carried out under the following conditions. Next, the excess adhesive attached to the polarizing film which has been immersed in the polyvinyl alcohol adhesive solution in the step 1 is lightly removed, and the polarizing film is sandwiched between the opposite side of the optical film 1 and the hardened layer and the KC4UZ. Configuration.

(alkali saponification treatment)

After the saponification treatment, the steps were followed by washing, neutralization, and water washing, followed by drying at 100 °C.

Step 3: The above laminate was sandwiched between two rotating rolls, and bonded at a speed of about 2 m/min under a pressure of 20 to 30 N/cm ² . At this time, it is carried out with care not to enter the bubble.

Step 4: The sample prepared in the step 3 was dried in a dryer at a temperature of 100 ° C for 5 minutes to prepare a polarizing plate.

Step 5: Apply a commercially available acrylic adhesive to the protective film side of the polarizing plate prepared in the step 4, and make the thickness after drying to 5 μm, and dry in an oven at 110 ° C for 5 minutes to form an adhesive layer in the adhesive layer. A peelable protective film is attached thereto. The polarizing plate 101 is produced by cutting (punching) the polarizing plate.

[Production of Liquid Crystal Display Device 201]

The upper polarizing plate of the liquid crystal display device (42LS5600 manufactured by LGD) was peeled off, and the polarizing plate 101 was attached to the liquid crystal cell as the upper polarizing plate. In other words, the adhesive layer of the polarizing plate 101 and the glass of the liquid crystal cell are bonded so that the KC4UZ of the polarizing plate 101 becomes the liquid crystal cell side. At this time, the transmission axis of the upper polarizing plate (polarizing plate 101) is the vertical direction, and the transmission axis of the lower polarizing plate is the left-right direction, and the crossed Nicols are arranged.

[Production of polarizing plates 102 to 109]

The polarizing plates 102 to 109 were produced in the same manner as in the production of the polarizing plate 101 except that the optical film 1 of the polarizing plate 101 was changed to the optical films 2 to 9, respectively.

[Production of Liquid Crystal Display Devices 202 to 209]

The liquid crystal display devices 202 to 209 are produced in the same manner as the liquid crystal display device 101 except that the polarizing plate 101 is changed to the polarizing plates 102 to 109.

"Evaluation" (SP value measurement)

The SP value of the additive (cyclic organic compound) contained in the curable resin of each of the optical films 1 to 9 was calculated by FUJITSU Technical Computing Solution SCIGRESS (manufactured by Fujitsu Co., Ltd.). Here, the value of the second digit below the decimal point of the calculated value is rounded off as the SP value.

(Visual recognition evaluation of image display device)

The liquid crystal display devices 201 to 209 produced by the respective optical films 1 to 9 were conditioned for 12 hours in an environment of 23° C. and 55% RH, and then black was displayed, and the visibility from the front view was evaluated based on the following criteria. .

<Evaluation criteria>

◎ ◎: Display unevenness due to minute coating unevenness was not observed at all.

◎: Display unevenness due to minute uneven coating was hardly observed.

○: Display unevenness due to minute coating unevenness was slightly observed, but there was no problem in practical use.

X: Display unevenness due to minute coating unevenness was observed considerably, and there was a problem in practical use.

(Determination of durability of polarizers)

The polarizing plates 101 to 109 produced above were subjected to a durability test at 80 ° C and 85% RH for 150 hours, and the veneer perpendicular transmittance after the durability test was subtracted from the veneer before the durability test. Orthogonal transmittance The amount of change in the orthogonal transmittance of the veneer is obtained. That is, the amount of change in the orthogonal transmittance of the veneer (%) = (the plate orthogonal penetration rate after the durability test (%) - the plate orthogonal penetration rate (%) before the durability test. Then The durability of the polarizer was evaluated based on the following criteria.

<Evaluation criteria>

◎: The amount of change in the transmittance of the orthogonal single plate (%) was less than 0.3%.

○: The amount of change (%) of the orthogonal single-plate transmittance was 0.3% or more and less than 0.65%.

×: The amount of change (%) of the transmittance of the orthogonal single plate was 0.65% or more (the level of the problem in practical use).

Further, the single plate orthogonal transmittance measurement was performed as follows. Two samples (about 5 cm × 5 cm) on which a polarizing plate was attached to the glass side of KC4UZ were placed on the glass, and the film side of the sample was fixed toward the light source, and two samples were measured, and the average value was taken as Veneer orthogonal transmittance. As a result of the measurement, UV3100PC manufactured by Shimadzu Corporation was used, and the orthogonal transmittance CT at a wavelength of 410 nm and a wavelength of 510 nm was measured 10 times, and the average value thereof was used.

(Evaluation of coating unevenness of optical film)

The base material (cellulose ester film) of each of the produced optical films 1 to 9 was irradiated with a fluorescent lamp from the back side of the coated surface side (hardened layer side), and the surface of the hardened layer was visually observed. All. Then, the frequency (number of occurrences) of the unevenness of the planarity was examined for 10 m ² , and this was converted into the number of planar unevenness per 1 m ² , and the coating unevenness was evaluated based on the following criteria.

<Evaluation criteria>

◎ ◎: Not all of the faces are 0, and the surface is good.

◎: The unevenness of the surface is converted into a frequency of 1 m ² , which is less than one, but it is a low frequency, and there is no concern.

○: The unevenness of the surface is converted into a frequency of one or more and less than three per 1 m ² , but it is not a problem in practical use.

X: The unevenness of the surface is converted into 1 or more per 1 m ² , which is a problem in practical use.

Table 1 shows the characteristics of the SP value and the like of the additive (compound) contained in the curable resin of each of the optical films 1 to 9, and the results of the respective evaluations.

As is clear from Table 1, the hardened layer on the substrate (cellulose ester film) contains an active energy ray-curable resin having an alicyclic structure, and the SP value is 17.0 to 21.0 [(J/cm ³ ) ^1/2 ]. a film having an aromatic ring structure or a cyclic organic compound having a polar substituent in an alicyclic structure, wherein the cyclic organic compound is an optical film of an ethylenically unsaturated monomer, and is used in a polarizing plate. The polarizer is excellent in durability, and the liquid crystal display device is excellent in suppressing deterioration in visibility during black display. It is considered that this is because the combination of the curable resin having an alicyclic structure and the cyclic organic compound of a specific structure, the hardened layer is sufficient even in a very severe environment of 80 ° C and 85% RH. It has low moisture permeability and can also inhibit coating unevenness of the hardened layer. In particular, as a result of the optical films 1, 3, and 5, it is understood that the SP value of the cyclic organic compound can surely suppress the hardened layer if the SP value is in the range of 18.0 to 20.0 [(J/cm ³ ) ^1/2 ]. The coating unevenness is surely suppressed from deterioration in visibility of the liquid crystal display device due to the uneven coating.

<Example 2> [Production of Optical Film 10]

The optical film 10 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-6. Further, the synthesis method of the cyclic organic compound B-6 is as follows.

(Synthesis method of B-6)

To a 0.5 mL solution of hexafluoroisopropanol of 5 mol% of palladium acetate and 30 mol% of copper acetate, 1 mmol of hexafluoroisopropanol (0.5 mL) of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped in an oxygen atmosphere (1 atm). The reaction was carried out for 1 hour at room temperature. Secondly, the mixture is washed with water. After the catalyst was removed, the solvent and the unreacted compound and the low molecular weight compound were distilled off by distillation at a maximum temperature of 200 ° C under a reduced pressure of 10 mmHg to obtain a polymer (cyclic organic compound B-6).

The number average molecular weight of the above polymer was measured by gel permeation chromatography (GPC-LALLS) with a light scattering detector and hydrogen furan (THF) as a solvent at a concentration of 0.001 g/cm ³ .

"Evaluation" (exudation evaluation)

The optical film 10 and the optical films 4 and 5 produced in Example 1 were subjected to a durability test at 1000 ° C and 85% RH for 1000 hours, and then the bleeding was evaluated by visual observation based on the following criteria.

<Evaluation criteria>

◎: No seepage was observed.

○: Partially weak oozing was observed, but it was not a problem in practical use.

Table 2 shows the characteristics of the SP value and the like of each of the optical films 4, 5, and 10, and the evaluation results of the bleeding.

As is clear from Table 2, the number average molecular weight of the cyclic organic compound contained in the hardened layer is preferably 500 or more, and more preferably 700 or more, between 208 and 700 from the viewpoint of suppressing bleeding.

<Example 3> [Production of Optical Film 11]

The optical film 11 was produced in the same manner as in the production of the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-7. Further, the synthesis method of the cyclic organic compound B-7 is as follows.

(Synthesis method of B-7)

A 1 second reaction tank equipped with a reflux condenser and a stirrer having a capacity of 2 liters and a second reaction tank having a plug capacity of 1 liter and a second reactor having a stirrer were connected in series. The first reaction tank was controlled at a temperature of 85 ° C, and the second reaction tank was controlled at a temperature of 85 ° C.

In the first reaction tank, a mixed liquid of 50/50 by weight of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) and cyclohexane as a polymerization solvent was fed at a flow rate of 30 parts by mass/minute. Further, a hexane solution of n-butyllithium as an organic lithium initiator was fed to the same reaction tank in an amount equivalent to 0.8 mmol per 100 parts by mass of styrene. The pressure was normal pressure, and the heat of reaction during the polymerization was carried out while refluxing the cyclohexane to the reflux condenser. The temperature of the reaction solution was substantially stable at 81 °C. The reaction liquid flowing out of the first reaction tank is continuously passed through the second reaction tank by a plug flow.

The anionic active terminal was deactivated by adding 10 times the amount of lithium to the obtained polymer solution. Then, in the polymer solution, the polymer is added in an amount of 0.05 parts by mass per 100 parts by mass. After the oxidizing agent, it was heat-treated at 215 ° C in a decompressed flash tank to remove volatile components. Further, the residual volatile component was removed by an extruder at 215 ° C with a reduced pressure exhaust port to obtain a polymer (cyclic organic compound B-7).

The number average molecular weight of the above polymer was measured by gel permeation chromatography (GPC-LALLS) with a light scattering detector using tetrahydrofuran (THF) as a solvent at a concentration of 0.001 g/cm ³ .

"Evaluation" (Evaluation of turbidity of coating liquid)

A turbidity meter (NHD2000 type, manufactured by Nippon Denshoku Industries Co., Ltd.) was used for the coating liquid (curable composition) used in the production of the optical film 11 and the optical films 4 and 5 produced in the first embodiment. The turbidity was measured by a quartz cell having an optical path length of 10 mm, and was evaluated based on the following criteria.

<Evaluation criteria>

◎: The turbidity was less than 0.5 mg/l.

○: The turbidity was 0.5 mg/l or more and less than 3.0 mg/l.

Table 3 shows the results of evaluation of the SP value and the like of each of the optical films 4, 5, and 11 and the turbidity.

As is clear from Table 3, the number average molecular weight of the cyclic organic compound contained in the hardened layer is preferably 240,000 or less, more preferably 200,000 or less, from the viewpoint of suppressing the turbidity of the coating liquid. Further, it is considered that if the number average molecular weight is between 242,000 and 950, and the value is close to 950 and is less than 20,000, the turbidity of the coating liquid can be sufficiently suppressed, and if it is less than 1,000, it can be satisfactorily and surely The turbidity of the coating liquid is suppressed.

<Example 4> (Production of hardened layer composition 2) <Modulation of polymer decane coupling agent coated microparticles>

To the container, 30 ml of methyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd.: Light Ester M), 3-mercaptopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-803), 1 ml and 100 ml of tetrahydrofuran as a solvent and 50 mg of azoisobutyronitrile (manufactured by Kanto Chemical Co., Ltd.: AIBN) as a polymerization initiator were replaced with N ₂ gas, and then heated at 80 ° C for 3 hours to prepare a polymer decane coupling agent. The resulting polymer decane coupling agent had a molecular weight of 16,000. Further, the measurement of the molecular weight was measured by a gel permeation chromatography apparatus.

Next, for cerium oxide sol (made by Nikko Catalyst Chemical Co., Ltd.: Si-45P, SiO ₂ concentration: 30% by weight, average particle diameter: 45 nm, dispersion medium: water), ion exchange resin is used for ion exchange, and ultrafiltration is performed. In the membrane method, water was replaced with ethanol to prepare ethanol, and 100 g of an ethanol dispersion of cerium oxide microparticles (SiO ₂ concentration: 30% by weight) was prepared.

100 g of this cerium oxide microparticle ethanol dispersion and 1.5 g of a polymer decane coupling agent were dispersed in 20 g (25 ml) of acetone, 20 mg of ammonia water having a concentration of 29.8% by weight was added thereto, and stirred at room temperature for 30 hours to obtain a polymer decane couple. The mixture is adsorbed to the cerium oxide microparticles.

Then, cerium oxide particles having an average particle diameter of 5 μm were added, and the unadsorbed polymer decane coupling agent in the solution was adsorbed to the cerium oxide particles by stirring for 2 hours, and then the unadsorbed polymer was removed by centrifugation. A cerium oxide coupling agent having an average particle diameter of 5 μm. 1000 g of ethanol was added to the cerium oxide fine particle dispersion to which the polymer decane coupling agent was adsorbed, and the cerium oxide fine particles were allowed to settle, separated, dried under reduced pressure, and then dried at 25 ° C for 8 hours to obtain a polymer decane coupling agent. Coated with cerium oxide (1). The obtained polymer decane coupling agent-coated cerium oxide (1) had an average particle diameter of 57 nm. The average particle size is measured by a laser particle size measuring device.

<Modulation of Hardened Layer Composition 2>

The polymer decane coupling agent prepared above was coated with the cerium oxide (1) and the following compound with stirring to prepare a hardened layer composition 2.

(microparticles)

Polymer decane coupling agent coated with cerium oxide (1) 60 parts by mass

(active wire hardening resin)

NK Ester A-DCP (tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) 35 parts by mass

(photopolymerization initiator)

Irgacure 184 (BASF Japan Co., Ltd.) 5 parts by mass

(additive)

Oxygenated compound (BYK Chemical Japan Co., Ltd.: BYK-UV3510) 1 part by mass

(cyclic organic compounds)

B-4 (YS Resin TO105, manufactured by YASUHARA Chemical Co., Ltd.) 8 parts by mass

(solvent)

(Production of optical film 12)

On the hardened layer 1 of the optical film 5 of Example 1, the hardened layer composition 2 produced above was applied by using a micro gravure coater, and dried at a constant rate of a drying zone temperature of 50 ° C and a reduced drying zone temperature of 50 ° C. While arranging with nitrogen gas until the oxygen concentration is 1.0% by volume or less, the illuminance of the irradiated portion is 100 mW/cm ² and the irradiation amount is 0.3 J/cm ² , and the coating layer is cured to form a dry film thickness of 2 μm. The hardened layer 2 is wound into a roll shape to form an optical film 12.

(Production of optical film 13)

The optical film 13 was produced in the same manner as in the production of the optical film 12 except that the hardened layer composition 2 produced above was applied to the cured layer 1 of the optical film 4 of Example 1 by using a micro gravure coater to form the hardened layer 2. .

"Evaluation" (The abrasion resistance test of optical film)

For the outermost surface of the hardened layer of each of the optical films 4, 5, 12, 13 Ten back and forth friction tests were carried out with different weights using a steel wool of #0000 at a stroke width of 10 mm and a speed of 500 mm/sec. Then, after rubbing with each load, the outermost surface of the sample was visually observed, and the load until the introduction of a flaw of 10 mm or more was measured, and it evaluated based on the following criteria. Furthermore, the greater the value of the load, the more excellent the scratch resistance.

<Evaluation criteria>

◎: The load was up to 2 kg, and no flaw of 10 mm or more was introduced.

○: A load of 10 mm or more was not introduced until the load reached 500 g.

Table 4 shows the results of evaluation of the SP value and the like of each of the optical films 4, 5, 12, and 13 and the scratch resistance.

As is clear from Table 4, by providing two layers of the hardened layer on the substrate, the scratch resistance is surely improved as compared with the configuration of the hard layer provided with one layer.

The optical film, the polarizing plate, and the image display device of the present embodiment described above can be expressed as follows.

An optical film comprising an optical film having a hardened layer on at least one side of a substrate, characterized in that the hardened layer comprises: an active energy ray-curable resin having an alicyclic structure, and a solubility parameter The SP value is in the range of 17.0 to 21.0 [(J/cm ³ ) ^1/2 ], and has at least one cyclic organic compound having an aromatic ring structure or a polar substituent in the alicyclic structure; and the above-mentioned cyclic organic compound system A polymer of ethylenically unsaturated monomers.

2. The optical film according to 1, wherein the ethylenically unsaturated monomer contains at least at least each of a structure of coumarone, anthracene, styrene, vinyltoluene, isoprene, piperylene, and decene. 1 person.

3. The optical film according to the above 1 or 2, wherein the cyclic organic compound has a number average molecular weight of 500 or more and less than 20,000.

4. The optical film according to any one of the above 1 to 3, wherein the cyclic organic compound has an aromatic ring structure.

5. The optical film according to any one of the above 1 to 4, wherein the cyclic organic compound has an SP value in a range of from 18.0 to 20.0 [(J/cm ³ ) ^1/2 ].

The optical film according to any one of the above 1 to 5, wherein the substrate is a cellulose ester film.

7. The optical film according to any one of the above 1 to 6, wherein The hardened layer is provided in two or more layers.

A polarizing plate characterized in that the optical film according to any one of the above 1 to 7 is bonded to one surface of the polarizing mirror.

An image display device characterized in that a polarizing plate as described in the above 8 is provided on a surface side of at least one side of the display cell.

[Industry use possibility]

The optical film of the present invention can be used for an image display device such as a polarizing plate or a liquid crystal display device.

Claims (9)

An optical film comprising an optical film having a hardened layer on at least one side of a substrate, wherein the hardened layer comprises: an active energy ray-curable resin having an alicyclic structure, and an SP value of a solubility parameter a cyclic organic compound having an aromatic ring structure or a polar substituent in an alicyclic structure in the range of 17.0 to 21.0 [(J/cm ³ ) ^1/2 ]; and the cyclic organic compound is ethyl The polymer of the unsaturated monomer, the active energy ray-curable resin is tricyclodecane dimethanol diacrylate, and the cyclic organic compound is any one of the compounds B-1 to B-7 represented by the following structural formula: , However, l, m, and n are repeating units, and R is a hydrogen atom or a methyl group. The optical film of claim 1, wherein the ethylenically unsaturated monomer contains at least one of each of a configuration of coumarone, anthracene, styrene, vinyl toluene, isoprene, piperylene, and decene. . The optical film of claim 1, wherein the cyclic organic compound has a number average molecular weight of 500 or more and less than 20,000. The optical film of claim 1, wherein the aforementioned cyclic organic compound has an aromatic ring structure. The optical film of claim 1, wherein the cyclic organic compound has an SP value in a range of from 18.0 to 20.0 [(J/cm ³ ) ^1/2 ]. The optical film of claim 1, wherein the substrate is a cellulose ester film. The optical film of claim 1, wherein the hardened layer is provided in two or more layers. A polarizing plate characterized in that an optical film according to any one of claims 1 to 7 is bonded to one side of a polarizing mirror. An image display device comprising the polarizing plate of claim 8 and a display cell sandwiching a liquid crystal layer in a pair of substrates, wherein the polarizing plate is disposed on at least one side of the display cell .