WO2016035404A1 - Optical film, polarizer, and image display device - Google Patents

Abstract

An optical film (15) has a cured layer (13) on at least one side of a film substrate (12). The cured layer (13) includes an active energy ray-curable resin having an alicyclic structure and at least one cyclic organic compound. Said cyclic organic compound is a polymer of ethylenically unsaturated monomers which have a solubility parameter (SP) value in a range of 17.0-21.0 [(J/cm³)^1/2] and have an aromatic ring structure or an alicyclic structure having a polar substituent.

Description

Optical film, polarizing plate and image display device

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

Generally, an optical film such as a polarizing plate protective film is disposed on the surface of a polarizing plate used in an image display device such as a liquid crystal display device (LCD). The polarizing plate protective film is formed by forming a cured layer on a base material made of, for example, a cellulose ester film. The cured layer is formed by applying a hard coat material on a substrate and curing it by irradiation with active energy rays.

In recent years, liquid crystal display devices such as tablets and smartphones are increasingly used outdoors. For this reason, not only high durability is calculated | required by liquid crystal display device itself, but high durability is also calculated | required also by the structural member (for example, polarizing plate) of a liquid crystal display device. However, under a high-temperature and high-humidity environment, there is a problem that the polarizing plate protective film easily allows moisture to pass therethrough, and there is a problem that the polarizing performance of the polarizer is deteriorated due to the moisture, and various studies have been made in recent years. For example, Patent Documents 1 and 2 attempt to improve the durability of the film by forming a cured layer of the optical film with a resin having a specific structure and reducing moisture permeability.

JP 2006-83225 A (see claim 1, paragraphs [0005], [0007], [0013], etc.) JP 2014-95890 A (see claim 1, paragraphs [0006], [0007], [0031], etc.)

However, the optical films of Patent Documents 1 and 2 are demanded in recent years under severer conditions of higher temperature and humidity (for example, in an environment at 80 ° C. and 85% relative humidity (hereinafter referred to as RH)). Then, it does not have low moisture permeability sufficiently, the protection performance of the polarizer is insufficient, and further improvement of the optical film has been demanded.

Further, if there is a minute coating unevenness with respect to the base material in the cured layer, when the optical film is used as a polarizing plate protective film of the image display device, the visibility deteriorates in the image display device (for example, during black display). It is known that unevenness occurs.

Therefore, it is desired to realize an optical film that can reduce moisture permeability in a higher temperature and high humidity environment, and can suppress unevenness in application of the cured layer and suppress deterioration in visibility in an image display device.

The present invention has been made in order to solve the above-described problems, and the object thereof is to sufficiently have low moisture permeability even under a severe environment of higher temperature and higher humidity, and to prevent coating unevenness of the cured layer. An object of the present invention is to provide an optical film that can suppress visibility deterioration in an image display device, a polarizing plate having the optical film, and an image display device having the polarizing plate.

The inventors of the present application have found that the above problem can be solved by forming a cured layer having the following constitution on at least one surface of the base material, and have reached the present invention. That is, the above object of the present invention is achieved by the following configuration.

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

According to the above configuration, an optical film having sufficiently low moisture permeability can be realized even in a severe environment of higher temperature and humidity. Moreover, since the coating unevenness of the cured layer can be suppressed in the optical film, visibility deterioration in the image display device can be suppressed when the optical film is applied to the polarizing plate of the image display device.

1 is a cross-sectional view illustrating a schematic configuration of an image display device according to an embodiment of the present invention. It is sectional drawing which shows the structure of the optical film applied to the polarizing plate of the said image display apparatus.

An embodiment of the present invention will be described below with reference to the drawings. In this specification, when the numerical range is expressed as A to B, the numerical value range includes the values of the lower limit A and the upper limit B. The present invention is not limited to the following contents.

The present inventors have found that the films of Patent Documents 1 and 2 do not have low moisture permeability sufficiently under severe durability conditions (for example, 80 ° C. and 85% RH) that are required in recent years. In order to further improve the optical film with respect to the problem that the protection performance of the child is insufficient, an optical film having the following configuration was examined. That is, it is an optical film having a cured layer obtained by adding a low molecular weight cyclic organic compound to an active energy ray-curable resin having an alicyclic structure on a substrate. The cyclic organic compound has an aromatic ring structure or a polar substituent in the alicyclic structure.

By adding the low molecular weight cyclic organic compound to the resin, it is possible to fill the voids of the resin with the cyclic organic compound and suppress the diffusion of water molecules in the cured layer. Even under severe conditions of high humidity, low moisture permeability can be achieved. However, it has been found that even if the optical film is reduced in moisture permeability as described above, when the optical film is applied to the polarizing plate of the image display device, a new problem that the visibility of the image display device deteriorates occurs. .

In response to such a problem of deterioration in visibility, the present inventors have reduced the optical film by adding a polymer cyclic organic compound having a specific structure to an active energy ray-curable resin having an alicyclic structure. It was found that the visibility deterioration of the image display device can be suppressed while achieving moisture permeation. Here, the high molecular cyclic organic compound having the above specific structure has an SP value as a solubility parameter in the range of 17.0 to 21.0 [(J / cm ³ ) ^1/2 ], and an aromatic ring. It is a polymer of an ethylenically unsaturated monomer having a structure or having a polar substituent in an alicyclic structure. The reason why visibility deterioration can be suppressed by adding the cyclic organic compound to the resin is considered as follows.

The deterioration of visibility in the image display device is considered to be caused by the occurrence of minute coating unevenness due to uneven distribution of the low molecular weight compound in the coating layer (cured layer) caused by charging of the base material of the optical film. It is done. That is, when the compound added to the coating layer has a low molecular weight, the compound easily moves in the coating layer due to charging of the base material, resulting in uneven distribution of the compound, which causes coating unevenness. By adding a polymer compound (polymer of ethylenically unsaturated monomer) to the coating layer, the compound is difficult to move through the coating layer even if the substrate is charged because the compound is a polymer. This makes it less susceptible to the charging of the material) and suppresses uneven distribution of the compound in the coating layer. Thereby, it is considered that the occurrence of minute application unevenness can be suppressed, and the deterioration of the visibility of the image display device due to the application unevenness can be suppressed.

Moreover, compatibility of curable resin and the said compound increases because SP value of a high molecular compound exists in said range. Furthermore, since the aromatic ring structure has a high polarity and the structure having a polar substituent in the alicyclic structure also has a high polarity, the compatibility of both is further increased by adding the above compound to the curable resin. For this reason, it is considered that the uneven distribution of the compound in the coating layer is further suppressed, thereby further suppressing the occurrence of uneven coating and further suppressing the deterioration of the visibility of the image display device. A preferable range of the SP value of the polymer compound is 18.0 to 20.0 [(J / cm ³ ) ^1/2 ]. In addition, the aromatic ring structure is more preferable than the structure having a polar substituent in the alicyclic structure in that the compatibility with the curable resin is further improved and coating unevenness can be effectively suppressed.

In addition, when the substrate is a cellulose ester film, the cellulose ester film has high hygroscopicity and easily allows moisture to pass through in a high temperature and high humidity environment, so that the polarizing performance of the polarizer is likely to deteriorate due to the influence of the moisture. Therefore, the configuration of the present embodiment in which the effect of low moisture permeability is obtained in a higher temperature and high humidity environment is very effective when the substrate is a cellulose ester film.

Hereinafter, a specific configuration of the image display device to which the optical film of the present embodiment is applied will be described.

[Configuration of image display device]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image display device 1 according to the present embodiment. The image display device 1 is, for example, a liquid crystal display device, and is configured by bonding a protective portion 3 to a polarizing plate 5 (particularly on an optical film 15 described later) of the liquid crystal display panel 2 via a filling layer 31. Yes. The filling layer 31 is an adhesive layer (void filler) made 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 protection unit 3 protects the surface of the liquid crystal display panel 2 and is formed of a front plate made of acrylic resin or glass, for example. Note that a touch panel (such as a capacitance method or a resistance film method) may be used as the protection unit 3 instead of the front plate.

The liquid crystal display panel 2 is configured by disposing polarizing plates 5 and 6 on both sides of a liquid crystal cell 4 (display cell) in 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 viewing 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 through 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 includes a polarizer 11 that transmits predetermined linearly polarized light, a film substrate 12 and a cured layer 13 that are sequentially stacked on the protective portion 3 side of the polarizer 11, and a liquid crystal cell 4 side of the polarizer 11. The optical film 14 is made up of. The film base 12 and the cured layer 13 constitute an optical film 15 as a protective film formed on the surface on the viewing side of the polarizer 11. The film substrate 12 is composed of a cellulose ester film. Therefore, the film substrate 12 is also referred to as a cellulose ester film substrate. By providing the cured layer 13 on the film substrate 12, the surface of the polarizing plate 5 can be protected.

Desirably, the film thickness of the film substrate 12 is in the range of 5 to 34 μm. By making the film substrate 12 thinner, the optical film 15 and the polarizing plate 5 can be made thinner, which can contribute to the thinning of the entire image display device 1.

The cured layer 13 may be composed of a single layer as shown in FIG. 1, but two or more layers may be laminated on the film substrate 12. For example, as shown in FIG. 2, the cured layer 13 may be configured by laminating a first cured layer 13a and a second cured layer 13b from the film base 12 side. Thus, by laminating a plurality of hardened layers 13, the scratch resistance can be improved, 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 made of the same material as the film substrate 12 (for example, cellulose ester) or may be made of other materials.

The film substrate 12 may be composed of a λ / 4 film. The λ / 4 film is a layer that imparts in-plane retardation of about ¼ of the wavelength to transmitted light, and in the present embodiment, the λ / 4 film is composed of a film that is obliquely stretched. The angle (crossing angle) formed between the slow axis of the λ / 4 film and the absorption axis of the polarizer 11 is 30 ° to 60 °, whereby the linearly polarized light from the polarizer 11 is converted into the λ / 4 film ( It is converted into circularly polarized light or elliptically polarized light by the film substrate 12).

Therefore, when an observer wears polarized sunglasses and observes a display image, the polarizing plate can be used regardless of how the transmission axis of the polarizer 11 (perpendicular to the absorption axis) and the transmission axis of the polarized sunglasses are misaligned. The light component parallel to the transmission axis of the polarized sunglasses contained in the light emitted from 5 (circularly polarized light or elliptically polarized light) can be guided to the eyes of the observer. Thereby, it can suppress that it becomes difficult to see a display image with the angle to observe. In addition, even when the observer does not wear polarized sunglasses, since it is circularly polarized light or elliptically polarized light that is emitted from the polarizing plate 5 and incident on the observer's eyes, linearly polarized light is directly incident on the observer's eyes. Compared to the above, the burden on the eyes of the observer can be reduced.

The polarizing plate 6 includes a polarizer 21 that transmits predetermined linearly polarized light, an optical film 22 that is disposed on the liquid crystal cell 4 side of the polarizer 21, and an optical that is disposed on the opposite side of the polarizer 21 from the liquid crystal cell 4. The film 23 is laminated. The polarizer 21 is disposed so that the transmission axis is perpendicular to the polarizer 11 (crossed Nicol state). The optical films 22 and 23 are provided to protect the front and back surfaces of the polarizing plate 6, but they may be made of the same material (for example, cellulose ester) as the film substrate 12 of the polarizing plate 5. However, it may be composed of other materials.

In addition, the above-described optical film 15 can be used for purposes other than the polarizing plate. In this case, the cured layer 13 may be provided on both surfaces of the film substrate 12. Therefore, in the optical film 15, it can be said that the cured layer 13 may be formed on at least one surface of the film substrate 12.

[Optical film]
Hereinafter, the detail of the optical film 15 mentioned above is demonstrated.

(Cured layer)
The cured layer of this embodiment contains an active energy ray-curable resin having an alicyclic structure (hereinafter also simply referred to as a curable resin). Specific examples of the alicyclic structure include norbornyl, tricyclodecanyl, tetracyclododecanyl, pentacyclopentadecanyl, adamantyl, diamantanyl and the like.

The active energy ray curable resin preferably has an ethylenically unsaturated double bond. Examples of the ethylenically unsaturated double bond group include polymerizable functional groups such as (meth) acryloyl group, vinyl group, styryl group and allyl group. Among them, (meth) acryloyl group and —C (O) OCH═ CH ₂ is preferred.

The active energy ray-curable resin having an alicyclic structure is preferably composed of 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, an amide group, a carbamoyl group, an ester group, an oxycarbonyl group, an ether group, or a group obtained by combining these. Specifically, polyols such as diols and triols having an alicyclic structure, carboxylic acids having (meth) acryloyl groups, vinyl groups, styryl groups, allyl groups, carboxylic acid derivatives, epoxy derivatives, isocyanate derivative compounds, etc. Can be easily synthesized by a one-step or two-step reaction.

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

（式中、Ｒ１は水素原子または炭素数１～３のアルキル基、Ｒ２は炭素数１～５のアルキレン基またはアルキレンオキサイド基、Ｒ３は水素原子または炭素数１～３のアルキル基、ｎは１または２の整数。）

(Wherein R1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R2 is an alkylene group or alkylene oxide group having 1 to 5 carbon atoms, R3 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is 1) Or an integer of 2.)

（式中、Ｒ１、Ｒ３およびｎは、上記一般式（Ｉ）と同じ意味である。）

(Wherein R1, R3 and n have the same meaning as in the general formula (I)).

In the general formulas (I) and (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 having 1 to 5 carbon atoms or an alkylene oxide group, and preferably represents a methylene group, an ethylene group, a methylene oxide group, or an ethylene oxide group. R3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and preferably represents a hydrogen atom, a methyl group, or an ethyl group.

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

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

Examples of commercially available compounds represented by the above general formulas (I) and (II) include NK ester A-DCP (tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.). However, it is not limited to these.

　一般式（III）中、Ｌ及びＬ’は各々独立に二価以上の連結基を表し、同時に二価とはならない。ｎは１～３の整数を表す。

In general formula (III), L and L ′ each independently represent a divalent or higher valent linking group and are not divalent simultaneously. n represents an integer of 1 to 3.

　一般式（IV）中、Ｌ及びＬ’は各々独立に二価以上の連結基を表し、同時に二価とはならない。ｎは１～２の整数を表す。

In general formula (IV), L and L ′ each independently represent a divalent or higher valent linking group and are not divalent simultaneously. n represents an integer of 1 to 2.

　一般式（Ｖ）中、Ｌ及びＬ’は各々独立に二価以上の連結基を表し、同時に二価とはならない。ｎは１～２の整数を表す。

In general formula (V), L and L ′ each independently represent a divalent or higher valent linking group and are not divalent simultaneously. n represents an integer of 1 to 2.

　一般式（VI）中、Ｌ、Ｌ’及びＬ’’は各々独立に二価以上の連結基を表す。

In general formula (VI), L, L ′, and L ″ each independently represent a divalent or higher linking group.

　一般式（VII）中、Ｌ及びＬ’は各々独立に二価以上の連結基を表し、同時に二価とはならない。

In general formula (VII), L and L ′ each independently represent a divalent or higher linking group and are not divalent simultaneously.

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

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

In addition to the active energy ray-curable resin having the alicyclic structure, the cured layer is excellent in mechanical film strength (abrasion resistance, pencil hardness), and in the range not impairing the effects of the present invention, the following ultraviolet curing is performed. A functional resin may be contained. Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable resin. A curable epoxy resin or the like is preferably used, and an ultraviolet curable acrylate resin is particularly preferable.

As the ultraviolet curable acrylate resin, polyfunctional acrylate is preferable. 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 acryloyloxy groups or methacryloyloxy groups in the molecule. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerol triacrylate relay , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, tri Methylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerin tri Methacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexamethacrylate, polybasic acid acrylate. A monofunctional acrylate may also be used. Monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl Examples thereof include acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Such acrylates can be obtained from Nippon Kasei Kogyo Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., etc.

(Cyclic organic compounds)
The cured layer has an SP value in the range of 17.0 to 21.0 [(J / cm ³ ) ^1/2 ], and has an aromatic ring structure or a polar substituent in the alicyclic structure, It has one kind of cyclic organic compound.

<SP value>
The SP value is represented by the square root of the sum of the molar cohesive energy of each atomic group divided by the volume, and indicates the polarity per unit volume. This SP value is also called a solubility parameter (Solubility Parameter). When the force acting between the solvent and the solute is assumed to be an intermolecular force (regular solution theory), it is used as a measure for expressing the intermolecular force. Is done. From experience, it is known that the smaller the difference between the SP values of the two components, the greater the solubility (the two components are likely to be mixed). The SP value can be calculated by, for example, FUJITSU Technical Computing Solution SCIGRESS (manufactured by Fujitsu Limited).

From the viewpoint of improving the compatibility with the above-described active energy ray-curable resin having an alicyclic structure, the preferred range of the SP value of the cyclic organic compound is 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 at least one monocyclic or polycyclic ring exhibiting aromaticity. Examples thereof include a benzene-based aromatic ring having an aromatic ring in which one or a plurality of benzene rings are condensed or connected, a heteroaromatic ring having an element other than carbon in the ring structure, and the like. A benzene aromatic ring is preferred, and the number of aromatic rings to which the benzene ring is condensed or linked is usually 1 to 5, preferably 1 to 3.

<Structure having polar substituent in alicyclic structure>
The alicyclic structure of the cyclic organic compound may be a structure containing at least one cycloalkane or cycloalkene. Hereinafter, although the specific example of an alicyclic structure is shown, it is not limited to these.

Examples of the monocyclic cycloalkane include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, and cyclododecane. Examples of the monocyclic cycloalkene include cyclopropene, cyclobutene, cyclopropene, cyclohexene, cycloheptene, cyclooctene and the like. The cycloaliphatic structure is preferably cyclohexane or cyclohexene. The alicyclic structure is not limited to a single ring and may be polycyclic. Examples of the polycyclic structure include bicyclodecane, norbornene, norbornadiene and the like.

Examples of the polar substituent include, but are not limited to, a hydroxyl group, a carbonyl group, a carboxy group, an amino group, a nitro group, and a nitrile group. Preferably, they are a hydroxyl group and a carboxy group.

<Ethylenically unsaturated monomer>
The cyclic organic compound is a polymer of an ethylenically unsaturated monomer. Examples of ethylenically unsaturated monomers include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n-propyl, (meth) acrylic acid isopropyl, (meth) -n -Butyl, isobutyl (meth) acrylate, (meth) acrylic acid-n-hexyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid-n-heptyl, (meth) acrylic acid-n-octyl, (meth) 2-ethylhexyl acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, benzyl (meth) acrylate, ( 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, (meth) acrylate (Meth) acrylic monomers such as ril, glycidyl (meth) acrylate; styrene monomers such as styrene, vinyltoluene, α-methylcytylene; pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane tri (meth) acrylate , Pentaerythritol tetraacrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol hexaacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methylate, isodecyl methacrylate, n-lauryl acrylate N-stearyl acrylate, 1,6-hexanediol dimethacrylate, urethane acrylate For example, but not limited to. Preferred are (meth) acrylic acid and methyl (meth) acrylate.

The above-mentioned ethylenically unsaturated monomer preferably contains at least one of the structures of coumarone, indene, styrene, vinyltoluene, isoprene, piperylene and terpene. Examples of the terpene structure include a β-pinene structure, an α-pinene structure, a β-limonene structure, and an α-limonene structure. Further, a hydrogenated terpene structure obtained by hydrogen reduction of these structures may be used.

Hereinafter, specific examples of the cyclic organic compound that can be used in the present embodiment will be shown, but the cyclic organic compound is not limited thereto.

Examples of commercially available cyclic organic compounds include YS Resin TO125, YS Resin TO115, YS Resin TO105, YS Resin TO85, YS Resin TR105, Clearon K4100, Clearon K100, YS Polystar T80, and YS Polystar manufactured by Yashara Chemical Co., Ltd. UH115, YS Polyster NH, YS Resin SX100, YS Resin SX185, Knit Resin Coumarone V-120S manufactured by Nikkaku Chemical Co., Ltd., Knit Resin PH-25, Knit Resin PH-30-90T, Petcoal manufactured by Tosoh Corporation Examples include, but are not limited to, petrotac.

(Photopolymerization initiator)
The cured layer preferably contains a photopolymerization initiator to accelerate the curing of the actinic radiation curable resin. The content of the photopolymerization initiator is preferably such that the photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100 in terms of mass ratio. Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone and the like, and derivatives thereof. It is not something. Commercially available products may be used as the photopolymerization initiator, and preferred examples include Irgacure 184, Irgacure 907, and Irgacure 651 manufactured by BASF Japan.

(Fine particles)
The hardened layer may contain fine particles. Although it does not restrict | limit especially as microparticles | fine-particles, A silica, an alumina, a zirconia, a titanium oxide, antimony pentoxide etc. are mentioned, Preferably it is a silica. The silica fine particles may be hollow particles having cavities inside. Fine particles coated with a polymer silane coupling agent are particularly preferred because they exhibit good mechanical properties. The content is preferably a fine particle: active ray curable resin = 0.1: 100 to 400: 100.

(Polymer silane coupling agent)
The polymer silane coupling agent refers to a reaction product of a polymerizable monomer and a silane coupling agent (reactive silane compound). Such a polymer silane coupling agent can be obtained, for example, according to the method for producing a reaction product of a polymerizable monomer and a reactive silane compound disclosed in JP-A-11-116240.

Specific examples of the polymerizable monomer include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n-propyl, (meth) acrylic acid isopropyl, (meth) -N-butyl, isobutyl (meth) acrylate, (meth) acrylic acid-n-hexyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid-n-heptyl, (meth) acrylic acid-n-octyl, ( 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, benzyl (meth) acrylate , 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, (meth) acrylic acid -Hydroxyethyl, 2-hydroxypropyl (meth) acrylate, stearyl (meth) acrylate, glycidyl (meth) acrylate, 2-aminoethyl (meth) acrylate, ethylene oxide adduct of (meth) acrylic acid, (Meth) acrylic acid trifluoromethyl methyl, (meth) acrylic acid 2-trifluoromethyl ethyl, (meth) acrylic acid 2-perfluoroethyl ethyl, (meth) acrylic acid 2-perfluoroethyl-2-perfluorobutyl Ethyl, 2-perfluoroethyl (meth) acrylate, perfluoromethyl (meth) acrylate, difluorofluoromethyl methyl (meth) acrylate, 2-perfluoromethyl-2-perfluoroethyl methyl (meth) acrylate, (Meth) acrylic acid 2-perfluorohexylethyl (Meth) acrylic acid-based monomers such as (meth) acrylic acid 2-perfluorodecylethyl and (meth) acrylic acid 2-perfluorohexadecylethyl; styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and Styrene monomers such as salts thereof; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; silicon-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; maleic anhydride, maleic acid, Monoalkyl and dialkyl esters of maleic acid; fumaric acid, monoalkyl and dialkyl esters of fumaric acid; maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexyluma Nitrile group-containing vinyl monomers such as imide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide; amide group-containing vinyl monomers such as acrylamide and methacrylamide; vinyl acetate, vinyl propionate, vinyl pivalate, benzoate Vinyl esters such as vinyl acid and vinyl cinnamate; Alkenes 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, trimethylolpropane tri (meth) acrylate, pentaerythritol tetraacrylate, ditrimethylolpropane Tora (meth) acrylate, dipentaerythritol hexaacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl acrylate, n-stearyl acrylate, 1,6 -Hexanediol dimethacrylate, perfluorooctylethyl methacrylate, trifluoroethyl methacrylate, urethane acrylate and the like and mixtures thereof.

As the reactive silane compound, an organosilicon compound represented by the following formula (1) is preferably used.
XR-Si (OR) ₃ (1)
(In the formula, R represents an organic group having 1 to 10 carbon atoms selected from a substituted or unsubstituted hydrocarbon group. X represents a (meth) acryloyl group, an epoxy group (glycid group), a urethane group, an amino group, One or more functional groups selected from fluoro groups.)

Specific examples of the organosilicon compound represented by the formula (1) include 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxymethyltrimethoxysilane, γ-glycidoxymethyltriethoxysilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β-glycidoxyethoxy) Propyltrimethoxysilane, γ- (meth) acrylooxymethyltrimethoxy Lan, γ- (meth) acrylooxymethyltrioxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyl Trimethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, 3-ureidoisopropylpropyltriethoxy Silane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, trifluoropropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysila , N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and the like, and mixtures thereof.

Polymeric silane coupling agent is prepared by reacting a polymerizable monomer with a reactive silane compound. Specifically, an organic solvent solution in which a reactive silane compound is mixed in an amount of 0.5 to 20 parts by weight, further 1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer is prepared, and polymerization is started. It can be obtained by adding an agent and heating.

(Method for preparing polymer silane coupling agent coated fine particles)
Specifically, the polymer silane coupling agent-coated fine particles can be prepared by adding a polymer silane coupling agent to a fine particle organic solvent dispersion and coating the fine particles with the polymer silane coupling agent in the presence of an alkali. The average particle diameter of the resulting polymer silane coupling agent-coated fine particles is preferably 5 to 500 nm, more preferably 10 to 200 nm, from the viewpoint of securing optical properties when used in an optical film.

The content of the polymer silane coupling agent-coated fine particles in the cured layer is preferably 0.5 to 80 parts by mass, more preferably 1 to 60 parts by mass as the solid content, from the viewpoint of securing the film strength of the cured layer. .

(Conductive agent)
The hardened layer may contain a conductive agent in order to impart antistatic properties. Preferred conductive agents include metal oxide particles or π-conjugated conductive polymers. An ionic liquid is also preferably used as the conductive compound.

(Additive)
The cured layer may contain a fluorine-siloxane graft compound, a fluorine compound, a silicone compound, or a compound having an HLB value of 3 to 18 from the viewpoint of improving the coating property. The hydrophilicity can be easily controlled by adjusting the types and amounts of these additives. The HLB value is Hydrophile-Lipophile-Balance, that is, a hydrophilic-lipophilic balance, and is a value indicating the hydrophilicity or lipophilicity of a compound. The smaller the HLB value, the higher the lipophilicity, and the higher the value, the higher the hydrophilicity. The HLB value can be obtained by the following calculation formula.
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, HLB value = 20 × total formula weight of hydrophilic part / molecular weight (J. Soc. Cosmetic Chem., 5 (1954), 294) and the like.

Specific compounds of compounds having an HLB value of 3 to 18 are listed below, but are not limited thereto. Figures in parentheses indicate HLB values. Made by Kao Corporation: 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 7 9 (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), manufactured by Nissin Chemical Industry Co., Ltd .: Surfynol 104E (4), Surfynol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4), Surfinol 104S (4), Surfi Knoll 420 (4), Surfynol 440 (8), Surfynol 46 (13), Surfynol 485 (17), Surfynol SE (6), Shin-Etsu Chemical Co., Ltd.: X-22-4272 (7), X-22-6266 (8).

The fluorine-siloxane graft compound refers to a copolymer compound obtained by grafting polysiloxane and / or organopolysiloxane containing siloxane and / or organosiloxane alone on at least a fluorine resin. Such a fluorine-siloxane graft compound can be prepared by a method as described in Examples described later. Alternatively, examples of 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, OPTOOL DAC, etc. manufactured by Daikin Industries, Ltd.

Examples of silicone compounds are 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, manufactured by Big Chemie Japan KK: BYK-UV3576, BYK-UV3535, BYK-UV3510, BYK-UV3505, BYK-UV3500, BYK-UV3510, and the like. These components are preferably added in a range of 0.005 parts by mass or more and 10 parts by mass or less with respect to the solid component in the cured layer composition. Two or more kinds of these components may be added 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 contain an ultraviolet absorber described in the cellulose ester film described later. As a structure of the film in the case of containing an ultraviolet absorber, when the cured layer is composed of two or more layers, the cured layer in contact with the film substrate preferably contains the ultraviolet absorber.

The content of the ultraviolet absorber is preferably such that the mass ratio is ultraviolet absorber: curable resin = 0.01: 100 to 20: 100.

(solvent)
The cured layer is a component that forms the cured layer described above, diluted with a solvent that swells or partially dissolves the film substrate, and is applied as a cured layer composition on the film substrate in the following manner, dried. It is preferable to provide it by curing.

Solvents include ketones (methyl ethyl ketone, acetone, etc.) and / or acetate esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (ethanol, methanol, normal propanol, isopropanol), propylene glycol monomethyl ether, cyclohexanone, methyl isobutyl ketone. Etc. are preferable. The coating amount of the cured layer composition is suitably an amount that results in a wet film thickness of 0.1 to 80 μm, and preferably an amount that results in a wet film thickness of 0.5 to 30 μm. The dry film thickness is in the range of an average film thickness of 0.01 to 20 μm, preferably in the range of 1 to 15 μm. More preferably, it is in the range of 2 to 12 μm.

As a method for applying the cured layer composition, a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, or an ink jet method can be used.

(Laminated)
The cured layer is preferably composed of two or more layers from the viewpoint of surface hardness (abrasion resistance). When the cured layer is composed of two or more layers, it is preferable from the viewpoint of surface hardness that the outermost surface layer contains the above-described polymer silane coupling agent-coated fine particles. The content of the polymer silane coupling agent-coated fine particles is preferably in the range of polymer silane coupling agent-coated fine particles: curable resin = 0.1: 100 to 200: 100 by mass ratio.

When two or more cured layers are provided, the thickness of the cured 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 second cured layer is 0.01 to 25 μm. It is preferable that it is the range of these.

Two or more layers may be formed by simultaneous multilayers. The simultaneous multi-layer is to form a hardened layer by applying two or more hardened layers on a base material without going through a drying step.

In order to laminate the second hardened layer on the first hardened layer without going through a drying process, the layers are stacked one after another with an extrusion coater or simultaneously with a slot die having a plurality of slits. Can be done.

(Curing layer formation method)
After applying the cured layer composition, it may be dried and cured (irradiated with actinic radiation (also referred to as UV curing treatment)), and if necessary, may be heat treated after UV curing. The heat treatment temperature after UV curing is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and particularly preferably 120 ° C. or higher. By performing the heat treatment after UV curing at such a high temperature, a cured layer having excellent film strength can be obtained.

Drying is preferably performed at a temperature of 30% or more in the rate of drying section. More preferably, the temperature of the decreasing rate drying section is 50 ° C. or higher.

In general, it is known that the drying process changes from a constant state to a gradually decreasing state when drying starts. A section in which the drying speed is constant is called a constant rate drying section, and a section in which the drying speed decreases is called a decreasing rate drying section.

As a light source for UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

Irradiation conditions vary depending on each lamp, but the irradiation amount of 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 . In the UV curing treatment, oxygen removal (for example, replacement with an inert gas such as nitrogen purge) can be performed to prevent reaction inhibition by oxygen. The cured state of the surface can be controlled by adjusting the removal amount of the oxygen concentration.

When irradiating actinic rays, it is preferably performed while applying tension in the transport direction of the film, more preferably while applying tension in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying tension is not particularly limited, and tension may be applied in the conveying direction on the back roller, or tension may be applied in the width direction or biaxial direction by a tenter. Thereby, a film having further excellent flatness can be obtained.

There may be at least one cured layer on the optical film, and it may be composed of a plurality of layers. Moreover, there may be a cured layer on both sides of the optical film.

(Back coat layer)
You may provide a backcoat layer in the surface on the opposite side to the side which provided the hardened layer of the optical film. The back coat layer is provided to correct curling caused by providing a hardened layer or other layers by coating or CVD. That is, the degree of curling can be balanced by imparting the property of being rounded with the surface on which the backcoat layer is provided facing inward. In addition, it is also preferable that the back coat layer is preferably applied also as an anti-blocking layer. In that case, fine particles may be added to the back coat layer coating composition to provide an anti-blocking function. preferable.

As fine particles added to the backcoat layer, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, and oxide. Mention may be made of indium, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low haze, and silicon dioxide is particularly preferable. These fine particles are commercially available under the trade names of, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Nippon Aerosil Co., Ltd.). . Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used. Examples of the polymer fine particles include a silicone resin, a fluororesin, and an acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large anti-blocking effect while keeping haze low. The dynamic friction coefficient on the back side of the optical film used in this embodiment is preferably 0.9 or less, particularly preferably 0.1 to 0.9.

The fine particles contained in the backcoat layer are preferably contained in an amount of 0.1 to 50% by weight, more preferably 0.1 to 10% by weight, based on the binder. The increase in haze when the backcoat layer is provided is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.0 to 0.1%.

Specifically, the backcoat layer is preferably formed by applying a composition containing a solvent that dissolves or swells the transparent resin film (film substrate). The solvent to be used may include a solvent to be dissolved and / or a solvent to be swollen in addition to a solvent to be swelled, a composition in which these are mixed at an appropriate ratio depending on the degree of curl of the transparent resin film and the type of resin What is necessary is just to form by the application quantity.

In order to enhance the curl prevention function, it is effective to increase the mixing ratio of the solvent for dissolving the solvent composition to be used and / or the solvent for swelling, and to decrease the ratio of the solvent not to be dissolved. This mixing ratio is preferably (solvent to be dissolved and / or solvent to be swollen) :( solvent to be dissolved) = 10: 0 to 0.3: 9.7. Examples of the solvent for dissolving or swelling the transparent resin film contained in such a mixed composition include dioxane, acetone, methyl ethyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, cyclohexane, diacetone alcohol, 1 , 3-dioxolane, N-methylpyrrolidone, propylene glycol monomethyl ether acetate, propylene carbonate, cyclopentanone, 3-pentanone, 1,2-dimethoxyethane, tetrahydrofuran, ethyl lactate, bis (2-methoxyethyl) ether, acetic acid 2 -Methoxyethyl, propylene glycol dimethyl ether, trichloroethylene, methylene chloride, ethylene chloride, tetrachloroethane, trichloroethane, chloroform and the like. Examples of the solvent that does not dissolve include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, propylene glycol monomethyl ether, and hydrocarbons (toluene, xylene, cyclohexanol).

These coating compositions are preferably applied on the surface of the transparent resin film with a gravure coater, dip coater, reverse coater, wire bar coater, die coater, etc., with a wet film thickness of 1 to 100 μm, particularly 5 to 30 μm. Preferably there is. The back coat layer may contain a resin as a binder. Examples of the resin used as the binder for the backcoat layer include vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, vinyl acetate resin, vinyl acetate-vinyl alcohol copolymer, partially hydrolyzed vinyl chloride-vinyl acetate copolymer. Polymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, ethylene-vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, etc. Vinyl polymer or copolymer, nitrocellulose, cellulose acetate propionate (preferably acetyl group substitution degree 1.8-2.3, propionyl group substitution degree 0.1-1.0), diacetylcellulose, cellulose Cellulose derivatives such as acetate butyrate resin, maleic acid and / or Or acrylic acid copolymer, acrylic ester copolymer, acrylonitrile-styrene copolymer, chlorinated polyethylene, acrylonitrile-chlorinated polyethylene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylic resin Rubber resins such as polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amino resin, styrene-butadiene resin, butadiene-acrylonitrile resin, Examples thereof include, but are not limited to, silicone resins and fluorine resins. For example, as acrylic resins, Acrypet MD, VH, MF, V (manufactured by Mitsubishi Rayon Co., Ltd.), Hyperl M-4003, M-4005, M-4006, M-4202, M-5000, M-5001, M-4501 (manufactured by Negami Kogyo Co., Ltd.), Dialnal 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 BR-106, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118, etc. (Mitsubishi Rayon Co., Ltd.) acrylic and The methacrylic monomers such as various homopolymers and copolymers were prepared as raw materials are commercially available and can also be selected as appropriate preferred from among these. A cellulose resin layer such as diacetyl cellulose or cellulose acetate propionate is preferable.

The order of coating the backcoat layer may be before or after coating the cured layer on the side opposite to the backcoat layer of the optical film, but if the backcoat layer also serves as an anti-blocking layer, coat it first. It is desirable to do. Alternatively, the back coat layer can be applied twice or more before and after the coating of the hardened layer.

[Optical film characteristics]
(Surface shape)
The arithmetic average 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. By setting the arithmetic average roughness Ra within the above range, the visibility and the clearness are excellent. The arithmetic average roughness Ra is a value measured with an optical interference surface roughness meter (manufactured by ZYGO, NewView) according to JIS B0601: 2001.

(Haze)
The haze of the optical film is preferably in the range of 0.05% to 10% in view of visibility when used in an image display device. Haze can be measured according to JIS K7105 and JIS K7136.

(hardness)
About the hardness of an optical film, it is preferable that the pencil hardness which is a parameter | index of hardness is HB or more. If the pencil hardness is equal to or higher than HB, it is difficult to be damaged in the polarizing plate forming step. For pencil hardness, the cured optical layer was conditioned at a temperature of 23 ° C. and a relative humidity of 55% for 2 hours or more, and then the cured layer was JIS K5400 using a test pencil specified by JIS S 6006 under a load of 500 g. Is a value measured in accordance with the pencil hardness evaluation method defined by.

[Cellulose ester film substrate (hereinafter also referred to as film substrate)]
A film base material has a cellulose ester as a main component. Examples thereof include a cellulose diacetate film, a cellulose triacetate film, a cellulose acetate propionate film, and a cellulose acetate butyrate film.

Examples of commercially available cellulose ester films include Konica Minoltack KC8UX, KC4UX, KC8UY, KC4UAY, KC6UA, KC4UA, KC2UA, KC4UE and KC4UZ (manufactured by Konica Minolta, Inc.). The refractive index of the cellulose ester film is preferably 1.45 to 1.55. The refractive index can be measured according to 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. Lower fatty acid means a fatty acid having 6 or less carbon atoms. Examples of the lower fatty acid ester of cellulose include, for example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate and the like, and mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate. it can. Particularly preferably used lower fatty acid esters of cellulose are cellulose diacetate, cellulose triacetate, and cellulose acetate propionate. These cellulose esters can be used alone or in combination.

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

The cellulose triacetate preferably has an average degree of acetylation (bound acetic acid amount) of 54.0 to 62.5%, and more preferably cellulose triacetate having an average degree of acetylation of 58.0 to 62.5%. is there.

The cellulose triacetate preferably contains cellulose triacetate A and cellulose triacetate B. Cellulose triacetate A is a cellulose triacetate having a number average molecular weight (Mn) of 125,000 or more and less than 155000, a weight average molecular weight (Mw) of 265,000 or more and less than 310,000, and Mw / Mn of 1.9 to 2.1. . Cellulose triacetate B has an acetyl group substitution degree of 2.75 to 2.90, Mn of 155,000 or more and less than 180,000, Mw of 290000 or more and less than 360,000, and Mw / Mn of 1.8 to 2.0. A cellulose triacetate.

Cellulose acetate propionate has an acyl group having 2 to 4 carbon atoms as a substituent, and when the substitution degree of acetyl group is X and the substitution degree of propionyl group or butyryl group is Y, the following formula (I ) And (II) are preferably satisfied at the same time.
Formula (I) 2.6 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5

Among them, it is preferable that 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9.

The method for measuring the substitution degree of the acyl group can be measured according to ASTM-D817-96. The number average molecular weight (Mn) and molecular weight distribution (Mw) of the cellulose ester can be measured using high performance liquid chromatography. The measurement conditions are as follows.
Solvent: Methylene chloride Column: Shodex K806, K805, K803G
(Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (Tosoh Corporation)
A calibration curve with 13 samples from Mw = 1000000 to 500 was used. The 13 samples are preferably used at approximately equal intervals.

(Thermoplastic acrylic resin)
The film substrate may be configured by using a thermoplastic acrylic resin in combination with a cellulose ester resin. When used in combination, the mass ratio of the thermoplastic acrylic resin and the cellulose ester resin is preferably thermoplastic acrylic resin: cellulose ester resin = 95: 5 to 50:50.

Acrylic resin also includes methacrylic resin. The acrylic resin is not particularly limited but is preferably composed of 50 to 99% by mass of methyl methacrylate units and 1 to 50% by mass of other monomer units copolymerizable therewith. Examples of other copolymerizable monomers include alkyl methacrylates having 2 to 18 alkyl carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, alkyl acrylates such as acrylic acid and methacrylic acid. Unsaturated group-containing divalent carboxylic acids such as saturated acid, maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, Examples thereof include maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and the like. These may be used alone or in combination of two or more.

Of these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer. -Butyl acrylate is particularly preferably used. Further, the weight average molecular weight (Mw) is preferably 80,000 to 500,000, more preferably 110,000 to 500,000.

The weight average molecular weight of the acrylic resin can be measured by gel permeation chromatography. Commercially available acrylic resins include, for example, Delpet 60N, 80N (Asahi Kasei Chemicals Corporation), Dianal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry Co., Ltd.) )) And the like. Two or more acrylic resins can be used in combination.

(Λ / 4 film)
A λ / 4 film may be used as the cellulose ester film substrate. By using the λ / 4 film, when the optical film of the present embodiment is incorporated in an image display device, it is preferable from the viewpoint of excellent visibility and crosstalk.

A λ / 4 film refers to a film having an in-plane retardation of the film of about ¼ with respect to a predetermined light wavelength (usually in the visible light region). The λ / 4 film is preferably a broadband λ / 4 film having a phase difference of approximately ¼ of the wavelength in the visible light wavelength range in order to obtain almost perfect circularly polarized light in the visible light wavelength range. .

The λ / 4 film has an in-plane retardation value Ro (550) measured at a wavelength of 550 nm, preferably in the range of 60 nm to 220 nm, more preferably in the range of 80 nm to 200 nm, and more preferably in the range of 90 nm to 190 nm. More preferably, it is the range. The in-plane retardation value Ro is represented by the following formula.
Ro = (nx−ny) × d
However, in the formula, nx and ny are the maximum refractive index in the plane of the film (also referred to as the refractive index in the slow axis direction) out of the refractive index at 23 ° C. and 55% RH and the wavelength of 550 nm, and in the plane of the film. It is the refractive index in the direction perpendicular to the slow axis, and d is the thickness (nm) of the film. Ro 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).

Furthermore, in order to function effectively as a λ / 4 film, it is preferable that the relationship of Ro (590) −Ro (450) ≧ 2 nm is satisfied at the same time, and Ro (590) −Ro (450) ≧ 5 nm. More preferably, Ro (590) −Ro (450) ≧ 10 nm is more preferable. Note that Ro (A) indicates an in-plane retardation value measured at a wavelength of Anm.

A circularly polarizing plate is obtained by laminating so that the angle between the slow axis of the λ / 4 film and the transmission axis of the polarizer described later is substantially 45 °. Substantially 45 ° means in the range of 30 ° to 60 °, more preferably in the range of 40 ° to 50 °. The angle between the in-plane slow axis of the λ / 4 film and the transmission axis of the polarizer is preferably 41 to 49 °, more preferably 42 to 48 °, and 43 to 47 °. Is more preferably 44 to 46 °.

The λ / 4 film is not particularly limited as long as it is an optically transparent resin. For example, an acrylic resin, a polycarbonate resin, a cycloolefin resin, a polyester resin, a polylactic acid resin, a polyvinyl alcohol resin, The cellulose-based resin described above can be used. Among these, from the viewpoint of chemical resistance, the λ / 4 film is preferably a cellulose resin or a polycarbonate resin. From the viewpoint of heat resistance, the λ / 4 film is preferably a cellulose resin.

(Retardation adjuster)
The retardation adjustment of λ / 4 can be performed by adding the following retardation adjusting agent to the above-described film base material. As the retardation adjusting agent, an aromatic compound having two or more aromatic rings as described in the specification of European Patent 911,656A2 can be used.

Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic heterocycle in addition to an aromatic hydrocarbon ring. Particularly preferred is an aromatic heterocycle, and the aromatic heterocycle is generally an unsaturated heterocycle. Of these, a 1,3,5-triazine ring is particularly preferred.

(Fine particles)
Cellulose ester film base materials have, for example, acrylic particles, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, It is preferable to contain matting agents such as inorganic fine particles such as aluminum oxide, magnesium silicate, and calcium phosphate, and a crosslinked polymer. The acrylic particles are not particularly limited, but are preferably multi-layered acrylic granular composites. Among these, silicon dioxide is preferable 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 in the range of 5 to 16 nm, and particularly preferably in the range of 5 to 12 nm.

(Ester compound)
It is preferable that a cellulose-ester film base material contains the ester compound or sugar ester represented by the following general formula (X) from a viewpoint of the dimensional stability by an environmental change. First, the ester compound represented by the general formula (X) will be described.

Formula (X) B- (GA) n-GB
Wherein B is a hydroxy group or carboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms. 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, and n represents an integer of 1 or more.)

In the general formula (X), the alkylene glycol component having 2 to 12 carbon atoms includes ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2 , 2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl- 1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1 There are 3-hexanediol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. Used as a mixture. In particular, alkylene glycols having 2 to 12 carbon atoms are particularly preferable because of excellent compatibility with cellulose acetate. Examples of the aryl glycol component having 6 to 12 carbon atoms include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol and the like, and these glycols can be used as one kind or a mixture of two or more kinds.

Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. These glycols may be used alone or in combination of two or more. Can be used as a mixture. Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, and the like. Used as a mixture of two or more. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5 naphthalene dicarboxylic acid, and 1,4 naphthalene dicarboxylic acid. Specific examples of the compound represented by formula (X) (compound X-1 to compound X-17) are shown below, but are not limited thereto.

(Sugar ester compound)
Next, the sugar ester compound will be described. The sugar ester compound is an ester other than cellulose ester, and is a compound obtained by esterifying all or part of the OH group of a sugar such as the following monosaccharide, disaccharide, trisaccharide or oligosaccharide. Examples of the sugar include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, nystose, 1F-fructosyl nystose, stachyose, maltitol, lactitol, lactulose, cellobiose, maltose, cellotriose, maltotriose, raffinose And kestose. In addition, gentiobiose, gentiotriose, gentiotetraose, xylotriose, galactosyl sucrose, and the like are also included. Among these compounds, compounds having a furanose structure and / or a pyranose structure are particularly preferable. Among these, sucrose, kestose, nystose, 1F-fructosyl nystose, stachyose and the like are preferable, and sucrose is more preferable. As oligosaccharides, maltooligosaccharides, isomaltooligosaccharides, fructooligosaccharides, galactooligosaccharides, and xylo-oligosaccharides can also be preferably used.

The monocarboxylic acid used for esterifying the sugar is not particularly limited, and known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid and the like can be used. The carboxylic acid to be used may be one kind or a mixture of two or more kinds. Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid , Saturated fatty acids such as tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laxelic acid And unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octenoic acid. Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof. Examples of preferred aromatic monocarboxylic acids include benzoic acid, aromatic monocarboxylic acids having an alkyl group or alkoxy group introduced into the benzene ring of benzoic acid, cinnamic acid, benzylic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid, tetralin An aromatic monocarboxylic acid having two or more benzene rings such as carboxylic acid, or a derivative thereof can be mentioned, and more specifically, xylic acid, hemelic acid, mesitylene acid, planicylic acid, γ-isojurylic acid, Julylic acid, mesitic acid, α-isoduric acid, cumic acid, α-toluic acid, hydroatropic acid, atropic acid, hydrocinnamic acid, salicylic acid, o-, m, p-anisic acid, creosote acid, o-, m, p-homosalicylic acid, o-pyrocatechuic acid, β-resorcylic acid, vanillic acid, isovanillic acid, veratrum acid o- veratric acid, gallic acid, asarone acid, mandelic acid, homoanisic acid, homovanillic acid, homoveratric acid, o- homoveratric acid, Futaron acid, can be mentioned p- coumaric acid, especially benzoic acid. Among the ester compounds esterified, an acetyl compound into which an acetyl group has been introduced by esterification is preferable.

The ester compound or sugar ester compound represented by the general 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. It is particularly preferred that

(Plasticizer)
The cellulose ester film substrate may contain a plasticizer as necessary. The plasticizer is not particularly limited, but is a polycarboxylic acid ester plasticizer, glycolate plasticizer, phthalate ester plasticizer, phosphate ester plasticizer, polyhydric alcohol ester plasticizer, acrylic plasticizer. Agents and the like. In these, an acrylic plasticizer is preferable from the viewpoint of easily controlling the cellulose ester film to the retardation value described later.

The polyhydric alcohol ester plasticizer is a plasticizer composed of an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule. A divalent to 20-valent aliphatic polyhydric alcohol ester is preferred.

When the above-described plasticizer is contained in the cellulose ester film substrate of the present embodiment, it is preferably contained in an amount of 1 to 50% by mass, more preferably 5 to 35% by mass, based on cellulose acetate. The content of 5 to 25% by mass is particularly preferable.

(UV absorber)
The cellulose ester film substrate of this embodiment may contain an ultraviolet absorber. Since the ultraviolet absorber absorbs ultraviolet rays of 400 nm or less, durability can be improved. In particular, the ultraviolet absorber preferably has a transmittance of 10% or less at a wavelength of 370 nm, more preferably 5% or less, and still more preferably 2% or less. Specific examples of the ultraviolet absorber are not particularly limited. For example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex salts, inorganic powders. Examples include the body.

More specifically, for example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6 -(Linear and side chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, and the like can be used. Commercially available products may be used. For example, TINUVIN such as TINUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, and TINUVIN 328 manufactured by BASF Japan Ltd. can be preferably used.

Preferably used ultraviolet absorbers are benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers, and particularly preferably benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers. In addition, a discotic compound such as a compound having a 1,3,5 triazine ring is also preferably used as the ultraviolet absorber. As the UV absorber, a polymer UV absorber can be preferably used, and a polymer type UV absorber is particularly preferably used.

As the benzotriazole ultraviolet absorber, TINUVIN 109 (octyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazole-2-) manufactured by BASF Japan Ltd., which is a commercial product, is available. Yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate), TINUVIN 928 (2 -(2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol) and the like can be used. As the triazine-based ultraviolet absorber, commercially available TINUVIN 400 (2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -manufactured by BASF Japan Ltd.- Reaction product of 5-hydroxyphenyl and oxirane), TINUVIN 460 (2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3-5 Triazine), TINUVIN 405 (2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester Reaction products) and the like.

The ultraviolet absorber is added by dissolving the ultraviolet absorber in an alcohol, such as methanol, ethanol, butanol or the like, an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof, and then becomes a film substrate. It may be added to the resin solution (dope) or directly during the dope composition. For an inorganic powder that does not dissolve in an organic solvent, a dissolver or a sand mill is used in the organic solvent and cellulose acetate to disperse and then added to the dope.

The amount of the ultraviolet absorber used is preferably 0.5 to 10% by mass, more preferably 0.6 to 4% by mass with respect to the cellulose acetate film.

(Antioxidant)
The cellulose ester film substrate of the present embodiment may further contain an antioxidant (deterioration inhibitor). The antioxidant has a role of delaying or preventing the cellulose acetate film from being decomposed by a residual solvent amount of halogen in the cellulose acetate film, phosphoric acid of a phosphoric acid plasticizer, or the like. As the antioxidant, hindered phenol compounds are preferably used. For example, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl) are used. -4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3 5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- 3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3 5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate Etc. The amount of these compounds added is preferably 1 ppm to 10000 ppm by weight and more preferably 10 to 1000 ppm with respect to the cellulose acetate film.

(Disadvantage)
The cellulose ester film substrate preferably has a defect of 5 μm or more in diameter of 1 piece / 10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less. Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined.

The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape such as transfer of a roller scratch or an abrasion, the size can be confirmed by observing the defect with the reflected light of a differential interference microscope.

When the number of defects is more than 1/10 cm square, for example, when a tension is applied to the film during processing in a later process, the film may be broken with the defect as a starting point and productivity may be reduced. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.

Moreover, even when it cannot be visually confirmed, when the cured layer is formed, the coating film may not be formed uniformly, resulting in a defect (missing coating). Here, the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign matter in the film forming stock solution, or a foreign matter mixed in the film forming. This refers to the foreign matter (foreign matter defect) in the film. In addition, the cellulose ester film base material preferably has a breaking elongation in at least one direction of 10% or more, more preferably 20% or more, as measured in accordance with JIS-K7127-1999. The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming.

(optical properties)
The cellulose ester film base material preferably has a total light transmittance of 90% or more, more preferably 92% or more. Moreover, as a realistic upper limit, it is about 99%. The haze value is preferably 2% or less, more preferably 1.5% or less. The total light transmittance and haze value can be measured according to JIS K7361 and JIS K7136.

Further, the in-plane retardation value Ro of the cellulose ester film substrate is preferably in the range of 0 to 5 nm, and the retardation 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. Alternatively, the retardation Ro is preferably in the range of 30 to 200 nm, and more preferably in the range of 30 to 90 nm. The retardation 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 retardation 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
(Where nx is the refractive index in the slow axis direction in the plane of the film base, ny is the refractive index in the direction perpendicular to the slow axis in the plane of the film base, and nz is the thickness direction of the film base) (Refractive index, d represents the thickness (nm) of the film substrate, respectively)

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

[Film formation of cellulose ester film]
Next, although the example of the film forming method of the cellulose-ester film which is an example of a film base material is demonstrated, the film forming method is not limited to this. As a method for producing a cellulose ester film, a production method such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, a hot press method, or the like can be used.

(Organic solvent)
An organic solvent useful for forming a resin solution (dope composition) in the case of producing a cellulose ester film by a solution casting film forming method described later is one that can simultaneously dissolve a cellulose ester resin and other additives. Can be used without limitation. For example, as a chlorinated organic solvent, methylene chloride, as a non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 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, iso-propanol, n-butanol, sec-butanol, tert-butanol, etc. Can, methylene chloride, methyl acetate, ethyl acetate, may be used preferably acetone. The solvent is preferably a dope composition in which a total of 15 to 45 mass% of cellulose ester resin and other additives are dissolved.

(Solution casting film forming method)
In the solution casting film forming method, a step of preparing a dope by dissolving a resin and an additive in a solvent, a step of casting the dope on a belt-shaped or drum-shaped metal support, and drying the cast dope as a web It is carried out by a step of peeling off from the metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished cellulose ester film.

As the metal support, a stainless steel belt or a drum whose surface is plated with a casting is preferably used.

The width of the cast (casting) can be 1 to 4 m. The surface temperature of the metal support in the casting process is set to −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferred because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate.

A preferable support temperature is appropriately determined at 0 to 100 ° C., and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. .

In particular, it is preferable to efficiently dry by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

In order for the cellulose ester film to obtain good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 60%. It is 130% by mass, particularly preferably 20 to 30% by mass or 70 to 120% by mass. The amount of residual solvent is defined by the following formula.
Residual solvent amount (% by mass) = {(MN) / N} × 100
In addition, M is the mass of the sample collected at any time during or after the production of the web or film, and N is the mass after heating at 115 ° C. for 1 hour.

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

In the film drying process, generally, a roller drying method (a method in which webs are alternately passed through a plurality of rollers arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.

In the stretching step, the film can be sequentially or simultaneously stretched in the longitudinal direction (MD direction) and the lateral direction (TD direction). The draw ratios in the biaxial directions perpendicular to each other are preferably in the range of 1.0 to 2.0 times in the MD direction and 1.05 to 2.0 times in the TD direction, respectively. More preferably, it is carried out in the range of 1.0 to 1.5 times and 1.05 to 2.0 times in the TD direction. For example, a method of making a difference in peripheral speed between a plurality of rollers and stretching in the MD direction using the difference in peripheral speed of the roller between them, fixing both ends of the web with clips and pins, and widening the interval between the clips and pins in the traveling direction And a method of stretching in the MD direction, a method of stretching in the lateral direction and stretching in the TD direction, a method of stretching the MD direction and the TD direction simultaneously, and stretching in both directions.

It is preferable to perform the width maintenance or the stretching in the width direction in the film forming process by a tenter, and it may be a pin tenter or a clip tenter.

The film transport tension in the film forming process 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.

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

The Tg of the cellulose ester film can be controlled by the material type constituting the film and the ratio of the constituting materials. The Tg when the cellulose ester film is dried is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. Especially preferably, it is 150 degreeC or more. The glass transition temperature is preferably 190 ° C. or lower, more preferably 170 ° C. or lower. The Tg of the cellulose ester film can be determined by the method described in JIS K7121. The stretching temperature is preferably 150 ° C. or more and the stretching ratio is 1.15 times or more because the surface is appropriately roughened. Roughening the surface of the cellulose ester film is preferable because it improves slipperiness and improves surface processability.

(Melt casting method)
The cellulose ester film substrate may be formed by a melt casting method. In the melt casting film forming method, a composition containing other additives such as a cellulose ester resin and a plasticizer is heated and melted to a temperature showing fluidity, and then a melt containing the fluid cellulose ester is cast. To do.

In the melt casting film forming method, the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy. It is preferable that a plurality of raw materials used for melt extrusion are usually kneaded in advance and pelletized.

Pelletization may be performed by a known method, for example, dry cellulose ester, plasticizer, and other additives are fed to an extruder with a feeder, kneaded using a single or twin screw extruder, and formed into a strand from a die. Can be extruded, water-cooled or air-cooled, and then cut.

Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.

A small amount of additives such as particles and antioxidants are preferably mixed in advance in order to mix uniformly.

The extruder is preferably processed at a temperature as low as possible so that it can be pelletized so that the shearing force is suppressed and the resin does not deteriorate (molecular weight reduction, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

Film formation is performed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.

Using a single-screw or twin-screw extruder, the pellets are melted at a temperature of about 200 to 300 ° C, filtered through a leaf disk filter, etc. to remove foreign matter, and then formed into a film from the T die. The cellulose ester film is formed by niping the film with a cooling roller and an elastic touch roller and solidifying the film on the cooling roller.

When introducing from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition and the like under vacuum, reduced pressure, or inert gas atmosphere.

The extrusion flow rate is preferably adjusted stably by introducing a gear pump or the like. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances. The stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately intertwined and compressed, and the contact points are sintered and integrated. The density of the fiber is changed depending on the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.

Additives such as plasticizers and particles may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.

The cellulose ester film temperature on the touch roller side when the cellulose ester film is nipped by the cooling roller and the elastic touch roller is preferably Tg or more (Tg + 110 ° C.) or less of the film. A known roller can be used as the roller having an elastic surface used for such a purpose.

The elastic touch roller is also called a pinching rotator. A commercially available elastic touch roller can also be used.

When peeling the cellulose ester film from the cooling roller, it is preferable to control the tension to prevent deformation of the film.

Moreover, it is preferable that the cellulose ester film obtained as described above is stretched by the stretching operation after passing through the step of contacting the cooling roller.

As the stretching method, a known roller stretching machine or tenter can be preferably used. The stretching temperature is usually preferably in the temperature range of Tg to (Tg + 60) ° C. of the resin constituting the film.

Before winding, the end may be slit and trimmed to the width of the product, and knurled (embossed) may be applied to both ends to prevent sticking and scratching during winding. The knurling method can be performed by heating or pressurizing using a metal ring having an uneven pattern on the side surface. The grip portion of the clip at both ends of the film is usually cut out and reused because the cellulose ester film is deformed and cannot be used as a product.

(Manufacturing method of obliquely stretched film)
The λ / 4 film can be produced by a method for producing an obliquely stretched film. The method for producing an obliquely stretched film is a method for producing a stretched film having a slow axis at an angle of more than 0 ° and less than 90 ° with respect to the extending direction of the film. As the unstretched film before oblique stretching, the cellulose ester film described above can be used.

Here, the angle with respect to the extending direction of the film is an angle in the film plane. Since the slow axis is usually expressed in the stretching direction or a direction perpendicular to the stretching direction, stretching having such a slow axis is performed by stretching at an angle of more than 0 ° and less than 90 ° with respect to the extending direction of the film. A film can be manufactured.

The angle between the film extension direction and the slow axis (orientation angle θ) can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °, more preferably 10 ° to 80 °. °, more preferably 40 ° to 50 °.

(Diagonal stretching)
The obliquely stretched film can be produced using an obliquely stretching apparatus (obliquely stretched tenter). As an obliquely stretched tenter, the orientation angle of the film can be set freely by changing the rail pattern in various ways, and furthermore, the orientation axis of the film can be oriented with high precision evenly on the left and right across the width direction of the film. An apparatus capable of controlling the film thickness and retardation with high accuracy can be preferably used.

(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. By forming the cured layer of this embodiment on a thin cellulose ester film substrate, the effect of this embodiment is more easily exhibited. The length of the cellulose ester film substrate is preferably 500 to 10,000 m, more preferably 1000 to 8000 m. By setting it as the range of the said length, it is excellent in the processability in application | coating, such as a hardened layer, and the handleability of cellulose-ester film base material itself.

The arithmetic average roughness Ra of the cellulose ester film substrate is preferably 2 to 10 nm, more preferably 2 to 5 nm. The arithmetic average roughness Ra can be measured according to JIS B0601: 1994.

[Other layers]
The optical film of this embodiment can be provided with other layers such as an antireflection layer and a conductive layer.

(Antireflection layer)
The optical film of this embodiment can be used as an antireflection film having an external light antireflection function by coating an antireflection layer on a cured layer.

The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is composed of a low refractive index layer having a lower refractive index than the protective film as the support, or a combination of a high refractive index layer and a low refractive index layer having a higher refractive index than the protective film as the support. Preferably it is.

<Low refractive index layer>
The low refractive index layer preferably contains silica-based fine particles, and the refractive index is preferably in the range of 1.30 to 1.45 when measured at 23 ° C. and wavelength of 550 nm.

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 in the range of 30 nm to 0.2 μm. Most preferred.

The composition for forming a low refractive index layer preferably contains at least one kind of particles having an outer shell layer and porous or hollow inside as silica-based fine particles. In particular, the particles having the outer shell layer and porous or hollow inside are preferably hollow silica-based fine particles.

The composition for forming a low refractive index layer may contain an organosilicon compound represented by the following general formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.
Formula (OSi-1): Si (OR) ₄
In the formula, R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used as the organosilicon compound represented by the general formula.

In addition, a compound having a thermosetting property and / or a photocurable property, which mainly contains a fluorine-containing compound containing a fluorine atom in a range of 35 to 80% by mass and containing a crosslinkable or polymerizable functional group, has a low refractive index. You may make it contain in the composition for layer formation. Specifically, a fluorine-containing polymer or a fluorine-containing sol-gel compound is used. Examples of the fluorine-containing polymer include hydrolysates and dehydration condensates of perfluoroalkyl group-containing silane compounds [eg (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane], and fluorine-containing monomers. Examples thereof include fluorine-containing copolymers having units and cross-linking reactive units as constituent units. In addition, you may add a solvent, a silane coupling agent, a hardening | curing agent, surfactant, etc. to the composition for low refractive index layer formation as needed.

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

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

<Conductive layer>
In the optical film, a conductive layer may be formed on the cured layer. As the conductive layer provided, a generally well-known conductive material can be used. For example, metal oxides such as indium oxide, tin oxide, indium tin oxide, gold, silver, and palladium can be used. These can be formed as a thin film on an optical film by a vacuum deposition method, a sputtering method, an ion plating method, a solution coating method, or the like. Moreover, it is also possible to form a conductive layer using the organic conductive material which is the above-described π-conjugated conductive polymer.

In particular, a conductive material that is excellent in transparency and conductivity, and that has a main component of any one of indium oxide, tin oxide, and indium tin oxide obtained at a relatively low cost can be suitably used. Although the thickness of the conductive layer varies depending on the material to be applied, it cannot be said unconditionally. However, the surface resistivity is 1000Ω or less, preferably 500Ω or less, and considering the economy, A range of 10 nm or more, preferably 20 nm or more and 80 nm or less, preferably 70 nm or less is suitable. In such a thin film, visible light interference fringes due to uneven thickness of the conductive layer are unlikely to occur.

〔Polarizer〕
Next, a polarizing plate using the optical film of this embodiment will be described. The polarizing plate can be produced by a general method. For example, an optical film is subjected to alkali saponification treatment, and the treated optical film is bonded to one surface of a polarizing film (polarizer) produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Is preferred.

The optical film may be bonded to the other surface of the polarizer, or the cellulose ester film substrate described above may be bonded. The film thickness of the film substrate to be bonded to the other surface is preferably in the range of 5 to 100 μm, more preferably in the range of 5 to 34 μm, from the viewpoint of adjusting smoothness and curl balance and further improving the effect of preventing winding deviation.

The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction, and a typical polarizing film that is known at present is a polyvinyl alcohol polarizing film. The polarizing film includes a polyvinyl alcohol film dyed with iodine and a dichroic dye dyed, but is not limited thereto.

For the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxial stretching or dyeing, or after uniaxial stretching after dyeing, a film subjected to durability treatment with a boron compound is preferably used. The thickness of the polarizing film is 5 to 30 μm, preferably 8 to 15 μm.

A polarizing plate is formed by bonding one side of the optical film of the present embodiment on the surface of the polarizing film. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

(Circularly polarizing plate)
A circularly polarizing plate can also be constituted using an optical film. That is, a circularly polarizing plate can be formed by laminating a polarizing plate protective film, a polarizer, and a λ / 4 film in this order. In this case, the angle formed between the slow axis of the λ / 4 film and the absorption axis (or transmission axis) of the polarizing film is 45 °. A long polarizing plate protective film, a long polarizer, and a long λ / 4 film (long diagonally stretched film) are preferably laminated in this order.

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

The circularly polarizing plate can be produced by a general method. In other words, it is preferable to attach an alkali saponified λ / 4 film to one surface of a polarizer produced by immersing and stretching a polyvinyl alcohol film in an iodine solution, using a completely saponified polyvinyl alcohol aqueous solution.

(Adhesive layer)
In order to bond the substrate of the liquid crystal cell and the polarizing plate, the pressure-sensitive adhesive layer used on one side of the film of the polarizing plate is preferably optically transparent and exhibits moderate viscoelasticity and pressure-sensitive adhesive properties.

Specific examples of the adhesive layer include adhesives or adhesives such as acrylic copolymers, epoxy resins, polyurethane, silicone polymers, polyethers, butyral resins, polyamide resins, polyvinyl alcohol resins, and synthetic rubbers. A film such as a drying method, a chemical curing method, a thermal curing method, a thermal melting method, a photocuring method, or the like can be formed and cured using a polymer such as the above. Among them, the acrylic copolymer can be preferably used because it is most easy to control the physical properties of the adhesive and is excellent in transparency, weather resistance, durability and the like.

(Image display device)
The optical film of this embodiment is preferable in that the performance excellent in visibility is exhibited by using it for an image display apparatus. As an image display device, a reflection type, a transmission type, a transflective type liquid crystal display device, 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, an organic EL display Examples thereof include a device and a plasma display. Among these image display devices, a liquid crystal display device is preferable because of its high visibility.

Protective part may be arranged on the further viewing side of the cured layer of the optical film of the viewing side polarizing plate. This protection part can be constituted by a front plate or a touch panel. The said protection part is bonded together by the said hardened layer via the filler (photocurable resin) for filling the space | gap between hardened layers. The front plate in particular of a protection part is not restrict | limited, A conventionally well-known thing, such as an acrylic board and a glass plate, can be used. Further, the material, thickness, and the like of the front plate can be appropriately selected according to the use of the image display device.

As the filler, a solvent-free filler is preferable, and as commercially available products, for example, SVR1120, SVR1150, SVR1320 (above, manufactured by Dexerials Corporation), or HRJ-60, HRJ-302, HRJ-53 (above, Kyoritsu Chemical Industry) And the like). When using a filler, one type may be used independently and multiple types may be used together.

Bonding of the optical film and the front plate can be performed as follows, for example. First, a filler is prepared. Then, a filler is applied to the surface of the cured layer of the optical film, and the front plate is overlaid 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 plate are bonded together. When the filler is applied to the surface of the cured layer, the surface free energy of the cured layer is set to 30 mN / m or more so that the filler is uniformly spread without being repelled at the end of the cured layer. An image display device that is maintained and has excellent visibility can be obtained.

〔Example〕
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<Example 1>
[Production of Cellulose Ester Film 1]
<Preparation of silicon dioxide dispersion>
Aerosil R812 (Nippon Aerosil Co., Ltd., average primary particle diameter of 7 nm)
10 parts by mass Ethanol 90 parts by mass The above was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed for 30 minutes with a dissolver to prepare a silicon dioxide dispersion dilution. The mixture was filtered with a fine particle dispersion dilution filter (Advantech Toyo Co., Ltd .: polypropylene wind cartridge filter TCW-PPS-1N).

<Preparation of Dope Composition 1>
(Cellulose ester resin)
Cellulose triacetate A (cellulose triacetate synthesized from linter cotton, acetyl group substitution degree 2.88, Mn = 14,000)
90 parts by mass (additive)
Ester Represented by General Formula (X) (Exemplary Compound X-1) 5 parts by mass Ester Represented by General Formula (X) (Exemplary Compound X-12) 4 parts by mass (UV absorber)
TINUVIN 928 (manufactured by BASF Japan Ltd.) 3 parts by mass (fine particles)
Silicon dioxide dispersion dilution 4 parts by mass (solvent)
Methylene chloride 432 parts by mass Ethanol 38 parts by mass The above was put into a sealed container, heated and stirred, and dissolved completely. Azumi filter paper No. Azumi filter paper No. 24 was used to prepare a dope (dope composition 1).

Next, the belt was cast evenly on a stainless steel band support using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100% by mass, and the stainless steel band support was peeled off. The cellulose ester film web was evaporated at 35 ° C., slit to 1.15 m width, and dried at a drying temperature of 140 ° C. while being stretched 1.15 times in the TD direction (film width direction) with a tenter. I let you. Then, it was dried for 15 minutes while being transported in a drying device at 120 ° C. with a number of rollers, slitted to a width of 1.3 m, knurled with a width of 10 mm and a height of 5 μm at both ends of the film, and wound around a core. The cellulose ester film 1 was obtained. The cellulose ester film 1 had a film thickness of 15 μm and a winding length of 3900 m.

In addition, the draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.01.

[Preparation of optical film 1]
The following cured layer composition 1 is applied onto the A side (the surface not in contact with the casting belt) of the produced cellulose ester film 1 using an extrusion coater, and the constant rate drying zone temperature is 50 ° C., the rate of decrease. After drying at a drying section temperature of 50 ° C., while purging with nitrogen so that the atmosphere has an oxygen concentration of 1.0% by volume or less, the irradiance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp, and the irradiation amount is set to 0. The coating layer was cured at 25 J / cm ² to form a cured layer 1 having a dry film thickness of 5 μm, and wound into a roll to produce an optical film 1.

<< Hardened layer composition 1 >>
<Composition of cured layer composition 1>
(Actinic radiation curable resin)
NK Ester A-DCP (Tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)
92 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 5 parts by mass (additive)
Silicone compound (BYK-UV3510, manufactured by BYK Japan)
1 part by mass (cyclic organic compound)
B-1 (YS Polystar NH, manufactured by Yasuhara Chemical Co., Ltd.) 8 parts by mass (solvent)
Propylene glycol monomethyl ether 10 parts by weight Methyl ethyl ketone 90 parts by weight

[Preparation of optical film 2]
Optical film 2 was produced in the same manner as optical film 1 except that cyclic organic compound B-1 was changed to cyclic organic compound B-2. The method for synthesizing cyclic organic compound B-2 is as follows.

(Synthesis method of B-2)
In an autoclave equipped with a stirrer, 2170 parts by weight of 4-n-octylstyrene (manufactured by Tokyo Chemical Industry Co., Ltd.), 2450 parts by weight of pure water, 50 parts by weight of calcium phosphate, 2.8 parts by weight of 50 ppm dodecylbenzenesulfonate Part, 166 parts by weight of benzoyl peroxide, 25 parts by weight of tert-butyl peroxyisopropyl carbonate and 135 parts by weight of α-methylstyrene dimer were accommodated. Next, using a stirrer, the mixture was stirred uniformly at room temperature and a rotation speed of 1000 rpm for 1 hour to obtain a mixed solution.

Next, the obtained mixed solution was heated, and the temperature in the autoclave was increased from a temperature of about 30 ° C. to 90 ° C. at a temperature increase rate of 10 ° C./min. And as process (A), initial polymerization was performed for 1 hour, keeping the temperature in an autoclave at the temperature of 90 ° C.

Next, the temperature in the autoclave was increased from 90 ° C. to 120 ° C. at a temperature increase rate of 10 ° C./min. In step (B), suspension polymerization was carried out for 5 hours while maintaining the temperature in the autoclave at 120 ° C. to obtain a polymer (organic cyclic compound B-2).

[Preparation of optical film 3]
An optical film 3 was produced in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-3. The method for synthesizing cyclic organic compound B-3 is as follows.

(Synthesis method of B-3)
In an autoclave equipped with a stirrer, 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 of 10% by weight, 2.8 parts by mass of 50 ppm dodecylbenzenesulfonate, 166 parts by mass of benzoyl peroxide, 25 parts by mass of tert-butyl peroxyisopropyl carbonate and 135 parts by mass of α-methylstyrene dimer were accommodated. Next, a mixed solution is prepared under the same conditions as in the method for synthesizing cyclic organic compound B-2, and suspension polymerization is further performed in steps (A) and (B) to obtain a polymer (cyclic organic compound B). -3) was obtained.

[Preparation of optical film 4]
Optical film 4 was prepared in the same manner as optical film 1 except that cyclic organic compound B-1 was changed to cyclic organic compound B-4 (YS Resin TO105, manufactured by Yasuhara Chemical Co., Ltd.).

[Preparation of optical film 5]
The optical film 5 was prepared in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to a cyclic organic compound B-5 (Knit Resin Coumarone V-120S, manufactured by Nikko Chemical Co., Ltd.). Produced.

[Preparation of optical film 6]
An optical film 6 was produced in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound C-1. The method for synthesizing cyclic organic compound C-1 is as follows.

(Synthesis method of C-1)
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.) is mixed with a styrene-butadiene random copolymer (25% styrene content, Asahi Kasei) as a rubbery elastic body. Kogyo Co., Ltd., trade name: Toughden 2000A) 4.0 parts by mass and 5.0 parts by mass of ethylbenzene were dissolved to obtain a raw material solution. A 1 part by mass ethylbenzene solution of azobisisobutyronitrile was prepared as a polymerization initiator.

Next, a raw material solution was supplied at a rate of 5.0 L / hour and an ethylbenzene solution of an initiator was supplied at a rate of 0.1 L / hour to a complete mixing tank having an internal volume of 20 L equipped with a double helical ribbon blade inside. Polymerization was conducted at a temperature of 120 ° C. under a stirring speed of 120 rpm. Subsequently, the polymerization reaction liquid that passed through the complete mixing tank was continuously introduced into a tubular reactor having an internal volume of 30 L, which was connected to the complete mixing tank, and was equipped with a static mixer inside. The polymerization reaction was performed under conditions such that the reaction solution temperature was 150 ° C. The obtained polymerization reaction liquid is continuously supplied to a devolatilization apparatus composed of a flash drum having a heater, and volatile components such as unreacted monomers and solvents are separated under conditions of a temperature of 220 ° C. and a pressure of 665 Pa. As a result, a polymer (cyclic organic compound C-1) was obtained. The content rate of the styrene structural unit in a polymer was 50 mass%, and the content rate of the methyl acrylate structural unit was 50 mass%. For reference, the structural formula of the cyclic organic compound C-1 is shown below.

[Preparation of optical film 7]
An optical film 7 was produced in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound C-2. The method for synthesizing cyclic organic compound C-2 is as follows.

(Synthesis method of C-2)
Using a 2-neck four-necked flask equipped with a thermometer, a stirrer, a dropping funnel and a condenser, 800 parts by mass of toluene (moisture: adjusted to 900 ppm), boron trifluoride gas 6.0 as a catalyst After charging the mass parts, the mixture was stirred while maintaining the temperature at 60 ° C., 160 parts by mass of α-pinene (manufactured by Yashara Chemical Co., Ltd.), 160 parts by mass of β-pinene (manufactured by Yashara Chemical Co., Ltd.), d-limonene (Yasuhara Chemical Co., Ltd.) A mixed solution of 160 parts by mass (manufactured by the company) and 32 parts by mass of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 3 hours, followed by stirring for 1 hour to react.

Next, the mixed solution is washed with water to remove the catalyst, and then toluene, unreacted monomers and low molecular weight compounds are distilled off by distillation under a reduced pressure condition of 10 mmHg at a maximum temperature of 200 ° C. to obtain a polymer (cyclic organic compound). C-2) was obtained. The content rate of the terpene structural unit in a polymer was 90 mass%, and the content rate of the styrene structural unit was 10 mass%. For reference, the structural formula of the cyclic organic compound C-2 is shown below.

[Preparation of optical film 8]
An optical film 8 was prepared in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to an organic compound C-3 (Dianal BR88, manufactured by Mitsubishi Rayon Co., Ltd.). 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.

[Preparation of optical film 9]
An optical film 9 was produced in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to a cyclic organic compound C-4 (biphenyl, manufactured by Tokyo Chemical Industry Co., Ltd.). For reference, the structural formula of the cyclic organic compound C-4 is shown below.

[Preparation of Polarizing Plate 101]
The optical film 1 was attached to one surface of the polarizing film, and a commercially available optical film KC4UZ (manufactured by Konica Minolta) was attached to the other surface of the polarizing film to produce a polarizing plate 101. More details are as follows.

(A) Production of Polarizing Film What was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water in 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400. After melt-kneading and defoaming, it was melt-extruded from a T-die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film. The obtained PVA film had an average thickness of 15 μm, a moisture content of 2.4%, and a film width of 3 m.

Next, the obtained PVA film was continuously processed in the order of pre-swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to produce a polarizing film. That is, the PVA film was preliminarily swollen in water at a temperature of 30 ° C. for 30 seconds, 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. Subsequently, the film was uniaxially stretched 6 times in a 50% aqueous solution with a boric acid concentration of 4% under the condition that the tension applied to the film was 700 N / m, and the potassium iodide concentration was 40 g / liter and the boric acid concentration was 40 g / liter. Then, it was immersed in an aqueous solution having a zinc chloride concentration of 10 g / liter and a temperature of 30 ° C. for 5 minutes for fixing. Thereafter, the PVA film was taken out, dried with 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, polarization performance of transmittance of 43.0%, polarization degree of 99.5%, and dichroic ratio of 40.1.

(B) Production of Polarizing Plate A polarizing plate was produced according to the following steps 1 to 5.

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

Process 2: The alkali saponification process was implemented on the following conditions with respect to the optical film 1 and KC4UZ. Next, excess adhesive adhered to the polarizing film immersed in the polyvinyl alcohol adhesive solution in Step 1 was lightly removed, and this polarizing film was sandwiched between the opposite surface of the optical film 1 from the cured layer and KC4UZ, and laminated.
(Alkaline saponification treatment)
Saponification process 4M-KOH 50 ° C 45 seconds Water washing step Water 30 ° C 60 seconds Neutralization step 10 parts HCl 30 ° C 45 seconds Water washing step Water 30 ° C 60 seconds After saponification treatment, water washing, neutralization, water washing are performed in this order. It is then dried at 100 ° C.

Step 3: The above laminate was sandwiched between two rotating rollers and bonded at a pressure of 20 to 30 N / cm ² at a speed of about 2 m / min. At this time, it was carried out with care to prevent bubbles from entering.

Step 4: The sample prepared in 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 pressure-sensitive adhesive to the protective film side of the polarizing plate prepared in Step 4 so that the thickness after drying is 5 μm, and dry in an oven at 110 ° C. for 5 minutes to form an adhesive layer. A peelable protective film was attached to the adhesive layer. This polarizing plate was cut (punched) to produce a polarizing plate 101.

[Production of Liquid Crystal Display Device 201]
The upper polarizing plate of the IPS mode liquid crystal display device (LGLS 42LS5600) was peeled off, and the polarizing plate 101 was attached to the liquid crystal cell as the upper polarizing plate. That is, the pressure-sensitive adhesive layer of the polarizing plate 101 and the glass of the liquid crystal cell were bonded so that KC4UZ of the polarizing plate 101 was on the liquid crystal cell side. At this time, the crossed Nicols were arranged so that the transmission axis of the upper polarizing plate (polarizing plate 101) was in the vertical direction and the transmission axis of the lower polarizing plate was in the horizontal direction.

[Production of Polarizing Plates 102 to 109]
Polarizing plates 102 to 109 were prepared in the same manner as 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]
Liquid crystal display devices 202 to 209 were manufactured in the same manner as the liquid crystal display device 101 except that the polarizing plate 101 was 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 using FUJITSU Technical Computing Solution SCIGRESS (manufactured by Fujitsu Limited). Here, the value obtained by rounding off the second decimal place of the calculated value was defined as the SP value.

(Visibility evaluation of image display device)
The liquid crystal display devices 201 to 209 manufactured using each of the optical films 1 to 9 were conditioned for 14 hours in an environment of 23 ° C. and 55% RH, and then displayed in black. Evaluation was based on criteria.
<Evaluation criteria>
A: Display unevenness due to minute application unevenness is not recognized at all.
A: Display unevenness due to minute application unevenness is hardly observed.
○: Some display unevenness due to minute application unevenness is recognized, but there is no problem in actual use.
X: Display unevenness due to minute application unevenness is considerably recognized, and there is a problem in actual use.

(Durability evaluation of polarizer)
The polarizing plates 101 to 109 produced above were subjected to a durability test that was allowed to stand at 80 ° C. and 85% RH for 150 hours, and then the single plate orthogonal transmission before the durability test from the single plate orthogonal transmittance after the durability test. The amount of change in the single plate orthogonal transmittance was determined by subtracting the rate. That is,
Amount of change in single plate orthogonal transmittance (%) = (Single plate orthogonal transmittance after durability test (%)-Single plate orthogonal transmittance before durability test (%)
It is. And polarizer durability was evaluated based on the following references | standards.
<Evaluation criteria>
(Double-circle): The variation | change_quantity (%) of the orthogonal single-plate transmittance was less than 0.3%.
A: The change (%) in the orthogonal single plate transmittance was 0.3% or more and less than 0.65%.
X: The change amount (%) of the orthogonal single plate transmittance was 0.65% or more (a level causing a problem in actual use).

In addition, the single plate orthogonal transmittance measurement was performed as follows. Create two samples (approx. 5cm x 5cm) with a polarizing plate on the glass so that the KC4UZ is on the glass side, set the sample with the film side facing the light source, and measure each of the two samples And the average value was made into the single plate orthogonal transmittance | permeability. The measurement results were obtained by measuring the orthogonal transmittance CT at a wavelength of 410 nm and a wavelength of 510 nm ten times using UV3100PC manufactured by Shimadzu Corporation, and using the average value.

(Evaluation of coating unevenness of optical film)
Irradiation with a fluorescent lamp from the back side of the substrate (cellulose ester film) of each of the optical films 1 to 9 with the coated surface side (cured layer side) facing up, surface irregularities on the cured layer surface Was visually observed. Then, the occurrence frequency (number) of planar unevenness was inspected for 10 m ² , converted into the number of planar unevenness per 1 m ² , and then coating unevenness was evaluated based on the following criteria.
<Evaluation criteria>
A: The surface unevenness is zero and the surface is excellent.
A: The surface unevenness is a frequency of less than 1 per 1 m ² , but it is low frequency and is not a concern.
○: The surface unevenness is a frequency of 1 or more and less than 3 per 1 m ² , but this is not a problem in practice.
X: Three or more surface irregularities are generated per 1 m ² , which is a practical problem.

Table 1 shows characteristics such as SP values of additives (compounds) contained in the curable resins of the optical films 1 to 9 and the results of each evaluation.

From Table 1, the cured layer on the base material (cellulose ester film) has an active energy ray-curable resin having an alicyclic structure and an SP value of 17.0 to 21.0 [(J / cm ³ ) ^1/2 And a cyclic organic compound having an aromatic ring structure or a polar substituent in the alicyclic structure, wherein the cyclic organic compound is a polymer of an ethylenically unsaturated monomer. It can be seen that ˜5 are excellent in the durability of the polarizer when applied to a polarizing plate, and are excellent in suppressing deterioration in visibility during black display of a liquid crystal display device. This is due to the combination of a curable resin having an alicyclic structure and a high molecular cyclic organic compound having a specific structure, so that the cured layer has sufficient moisture permeability even in a very severe environment of 80 ° C. and 85% RH. This is considered to be because the coating unevenness of the cured layer can be suppressed. In particular, when the SP value of the cyclic organic compound is in the range of 18.0 to 20.0 [(J / cm ³ ) ^1/2 ] from the results of the optical films 1, 3, and 5, the cured layer It can be said that uneven application can be reliably suppressed, and deterioration of the visibility of the liquid crystal display device due to the uneven application can be reliably suppressed.

<Example 2>
[Production of Optical Film 10]
An optical film 10 was produced in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-6. 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 containing 5 mol% palladium acetate and 30 mol% copper acetate, 0.5 mL solution of hexafluoroisopropanol of 1 mmol of styrene (manufactured by Tokyo Chemical Industry Co., Ltd.) is added dropwise at room temperature under an oxygen atmosphere (1 atm). The reaction was carried out for 1 hour. Next, the mixed solution is washed with water to remove the catalyst, and then the solvent, unreacted compound, and low molecular weight compound are 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) was obtained.

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

≪Evaluation≫
(Bleed-out evaluation)
About optical film 10 and optical film 4/5 produced in Example 1, after carrying out the durability test which is left to stand at 80 degreeC85% RH for 1000 hours, about bleed out visually based on the following references | standards evaluated.
<Evaluation criteria>
A: No bleed out is observed.
○: Partially weak bleed out is observed, but there is no practical problem.

Table 2 shows the evaluation results for the characteristics such as SP values of each optical film 4, 5, 10 and the bleed out.

From Table 2, the number average molecular weight of the cyclic organic compound contained in the cured layer is preferably 500 or more between 208 and 700, and more preferably 700 or more, from the viewpoint of suppressing bleed out. I can say that.

<Example 3>
[Preparation of optical film 11]
An optical film 11 was produced in the same manner as the optical film 1 except that the cyclic organic compound B-1 was changed to the cyclic organic compound B-7. The method for synthesizing cyclic organic compound B-7 is as follows.

(Synthesis method of B-7)
A first reaction tank having a capacity of 2 liters with a reflux condenser and a stirrer and a plug flow type second reaction tank having a capacity of 1 liter with a stirrer were connected in series. The temperature of the first reaction tank was controlled at 85 ° C, and the temperature of the second reaction tank was controlled at 85 ° C.

In the first reaction vessel, a 50/50 weight ratio mixture 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 / min. Separately, a hexane solution of n-butyllithium was fed as an organolithium initiator to the reaction vessel in an amount corresponding to 0.8 mmol per 100 parts by mass of styrene. The pressure was normal pressure, and the heat of reaction during polymerization was removed while refluxing cyclohexane in a reflux condenser. The temperature of the reaction solution was almost stabilized at 81 ° C. About the reaction liquid which flowed out from the 1st reaction tank, the 2nd reaction tank was passed by the plug flow continuously.

The anion active terminal was deactivated by adding 10 times the amount of lithium methanol to the obtained polymer solution. Thereafter, 0.05 parts by mass of an antioxidant per 100 parts by mass of the polymer was added to the polymer solution, followed by heat treatment at 215 ° C. in a reduced pressure flushing tank to remove volatile components. Further, the remaining volatile components were removed through an extruder with a vacuum vent at 215 ° C. to obtain a polymer (cyclic organic compound B-7).

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

≪Evaluation≫
(Evaluation of turbidity of coating solution)
About the coating liquid (curable composition) used in the production of the optical film 11 and the optical films 4 and 5 produced in Example 1, a turbidimeter (NHD2000 type, manufactured by Nippon Denshoku Industries Co., Ltd.), an optical path length of 10 mm The turbidity was measured using a quartz cell and evaluated based on the following criteria.
<Evaluation criteria>
A: Turbidity is less than 0.5 mg / l.
○: Turbidity is 0.5 mg / l or more and less than 3.0 mg / l.

Table 3 shows the evaluation results for the characteristics and turbidity of each optical film 4, 5, 11 such as SP value.

From Table 3, it can be said that the number average molecular weight of the cyclic organic compound contained in the cured layer is preferably 240000 or less and more preferably 200000 or less from the viewpoint of suppressing the turbidity of the coating solution. If the number average molecular weight is less than 20000, which is a value close to 950 between 242000 and 950, the turbidity of the coating solution can be sufficiently suppressed. It is considered that the degree can be sufficiently and reliably suppressed.

<Example 4>
(Preparation of cured layer composition 2)
<Preparation of polymer silane coupling agent coated fine particles>
In a container, 30 ml of methyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd .: Light Ester M), 1 ml of 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-803), 100 ml of tetrahydrofuran as a solvent, polymerization initiator Was added 50 mg of azoisobutyronitrile (manufactured by Kanto Chemical Co., Inc .: AIBN) and substituted with N ₂ gas, followed by heating at 80 ° C. for 3 hours to prepare a polymer silane coupling agent. The obtained polymer silane coupling agent had a molecular weight of 16,000. The molecular weight was measured with a gel permeation chromatography apparatus.

Next, silica sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: Si-45P, SiO ₂ concentration 30% by weight, average particle size 45 nm, dispersion medium: water) is ion-exchanged with an ion exchange resin, and an ultrafiltration membrane method is used. Then, water was replaced with ethanol to prepare 100 g of an ethanol dispersion of silica fine particles (SiO ₂ concentration 30 wt%).

100 g of the silica fine particle ethanol dispersion and 1.5 g of the polymer silane coupling agent are dispersed in 20 g (25 ml) of acetone, and 20 mg of aqueous ammonia having a concentration of 29.8% by weight is added thereto, followed by stirring at room temperature for 30 hours. The polymer silane coupling agent was adsorbed on the silica fine particles.

Thereafter, silica particles having an average particle diameter of 5 μm are added and stirred for 2 hours to adsorb the unadsorbed polymer silane coupling agent in the solution to the silica particles, and then the polymer silane coupling that has not been adsorbed by centrifugation. Silica particles having an average particle diameter of 5 μm adsorbing the agent were removed. 1000 g of ethanol is added to the silica fine particle dispersion adsorbing the polymer silane coupling agent, and the silica fine particles are precipitated, separated, dried under reduced pressure, and then dried at 25 ° C. for 8 hours to obtain a polymer silane coupling agent-coated silica (1 ) The obtained polymer silane coupling agent-coated silica (1) had an average particle size of 57 nm. The average particle size was measured with a laser particle size measuring device.

<Adjustment of cured layer composition 2>
The cured silane composition 2 was prepared by stirring and mixing the polymer silane coupling agent-coated silica (1) prepared above and the following compound.
(Fine particles)
Polymer silane coupling agent-coated silica (1) 60 parts by mass (active ray curable resin)
NK Ester A-DCP (Tricyclodecane dimethanol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)
35 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 5 parts by mass (additive)
Silicone compound (BYK-UV3510, manufactured by BYK Japan)
1 part by mass (cyclic organic compound)
B-4 (YS Resin TO105, manufactured by Yasuhara Chemical Co., Ltd.)
8 parts by mass (solvent)
Propylene glycol monomethyl ether 80 parts by weight Methyl acetate 20 parts by weight

(Preparation of optical film 12)
The cured layer composition 2 prepared above is applied onto the cured layer 1 of the optical film 5 of Example 1 using a micro gravure coater, and the constant rate drying zone temperature is 50 ° C. and the reduced rate drying zone temperature is 50 ° C. After drying, while purging with nitrogen so that the oxygen concentration is 1.0% by volume or less, using an ultraviolet lamp, the illuminance of the irradiated part is 100 mW / cm ² and the irradiation amount is 0.3 J / cm ^2. The layer was cured to form a cured layer 2 having a dry film thickness of 2 μm and wound into a roll to produce an optical film 12.

(Preparation of optical film 13)
Except that the cured layer composition 2 prepared above was applied on the cured layer 1 of the optical film 4 of Example 1 using a microgravure coater to form the cured layer 2, the same as the production of the optical film 12. Thus, an optical film 13 was produced.

≪Evaluation≫
(Abrasion resistance test of optical film)
Using the steel wool of # 0000 on the outermost surface of the cured layer of each of the optical films 4, 5, 12, and 13, a 10-reciprocal rubbing test was performed with different loads under the conditions of a stroke width of 10 mm and a speed of 500 mm / sec. did. And after rubbing with each load, the sample outermost surface was observed visually, the load until a 10 mm or more damage | wound entered was measured, and it evaluated based on the following references | standards. In addition, it shows that it is excellent in abrasion resistance, so that the value of a load is large.
<Evaluation criteria>
A: Scratches of 10 mm or more did not enter until the load reached 2 kg.
○: Scratches of 10 mm or more did not enter until the load reached 500 g.

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

From Table 4, it can be said that by providing two hardened layers on the base material, the scratch resistance is surely improved as compared with the constitution in which one hardened layer is provided.

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

1. An optical film having a cured layer on at least one surface of a substrate,
The cured layer is
An active energy ray-curable resin having an alicyclic structure;
The SP value, which is a solubility parameter, is in the range of 17.0 to 21.0 [(J / cm ³ ) ^1/2 ], has an aromatic ring structure, or has a polar substituent in the alicyclic structure. A kind of cyclic organic compound,
The optical film, wherein the cyclic organic compound is a polymer of an ethylenically unsaturated monomer.

2. 2. The optical film as described in 1 above, wherein the ethylenically unsaturated monomer contains at least one of the structures of coumarone, indene, styrene, vinyl toluene, isoprene, piperylene and terpene.

3. 3. The optical film as described in 1 or 2 above, wherein the cyclic organic compound has a number average molecular weight of 500 or more and less than 20000.

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

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

6. 6. The optical film as described in any one of 1 to 5, wherein the substrate is a cellulose ester film.

7. 7. The optical film as described in any one of 1 to 6, wherein two or more hardened layers are provided.

8. 8. A polarizing plate, wherein the optical film according to any one of 1 to 7 is bonded to one surface of a polarizer.

9. 9. An image display device, wherein the polarizing plate according to 8 is provided on at least one surface side of the display cell.

The optical film of the present invention can be used for image display devices such as polarizing plates and liquid crystal display devices.

1 Image display device 4 Liquid crystal cell (display cell)
5 Polarizing plate 11 Polarizer 12 Film base material (base material)
13 Hardened layer 15 Optical film

Claims (9)

An optical film having a cured layer on at least one surface of a substrate,
The cured layer is
An active energy ray-curable resin having an alicyclic structure;
The SP value, which is a solubility parameter, is in the range of 17.0 to 21.0 [(J / cm ³ ) ^1/2 ], has an aromatic ring structure, or has a polar substituent in the alicyclic structure. A kind of cyclic organic compound,
The optical film, wherein the cyclic organic compound is a polymer of an ethylenically unsaturated monomer. 2. The optical film according to claim 1, wherein the ethylenically unsaturated monomer contains at least one of the structures of coumarone, indene, styrene, vinyl toluene, isoprene, piperylene, and terpene. The optical film according to claim 1 or 2, wherein the cyclic organic compound has a number average molecular weight of 500 or more and less than 20000. The optical film according to any one of claims 1 to 3, wherein the cyclic organic compound has an aromatic ring structure. 5. The optical film according to claim 1, wherein the cyclic organic compound has an SP value in the range of 18.0 to 20.0 [(J / cm ³ ) ^1/2 ]. . The optical film according to any one of claims 1 to 5, wherein the substrate is a cellulose ester film. The optical film according to claim 1, wherein two or more of the cured layers are provided. A polarizing plate, wherein the optical film according to any one of claims 1 to 7 is bonded to one surface of a polarizer. 9. An image display device, wherein the polarizing plate according to claim 8 is provided on at least one surface side of the display cell.

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