KR101587374B1 - Process for production of hard coat film - Google Patents

Abstract

1 to 20% by weight of a plasticizer having a property of being formed by the solution softening method and having a property of being localized on the support side at the time of forming in the film forming process and also having a film thickness of 15 탆 or more and 30 The hard coat layer 51 is applied to the side of the thin film optical film (for example, the cellulose ester film 41) having a thickness of not more than 10 탆 and the concentration of the silica fine particles being greater than the average concentration for the entire thin film optical film.

Description

TECHNICAL FIELD [0001] The present invention relates to a hard coat film,

The present invention relates to a method for producing a hard coat film for applying a hard coat layer to a thin film optical film.

A hard coating film having a hard coating layer for preventing scratches is usually attached to the surface of the display device because the surface of the display device is likely to be scratched due to direct contact with the hands or contact with water. Particularly, in the liquid crystal display device, by attaching the hard coating film to the surface of the polarizing film (polarizer) of the polarizing plate on the light emitting side, the occurrence of scratches is prevented and the entire device is thinned.

An example of such a hard coating film is disclosed in Patent Document 1. In the example of Patent Document 1, a hard coating layer having a thickness of 20 占 퐉 is formed on one side of a film substrate having a thickness of 80 占 퐉 to prepare a hard coating film.

[0003] In recent years, along with a demand for a new thinness of a liquid crystal display device, an optical film (for example, a thin film optical film having a thickness of 15 to 30 [micro] m) thinner than a film substrate used for manufacturing a hard coating film of Patent Document 1 ), And a hard coating film formed by coating a hard coating layer on the surface was attached to a polarizing film to produce a liquid crystal display device, and as a result, display defects were found.

As a result of the investigation, it was found that the display defects were caused by scratches of the thin optical film as a base of the hard coat layer of the hard coat film. That is, in a hard coating film applied to a polarizing plate of a liquid crystal display, a hard coating layer is formed on one side of the thin film optical film and an adhesive for adhesion to the polarizing film is coated on the other side. At this time, if scratches are formed on the coating side of the hard coating layer in the thin film optical film, when the hard coating layer is cured and shrunk by irradiation with ultraviolet rays or the like, hardening shrinkage unevenness occurs at the portions where scratches occur and at portions where scratches are not generated. On the contrary, if a scratch is generated on the side of the adhesive side of the thin film optical film, the uneven application of the adhesive occurs at the portion where the scratches are generated and the portion where the scratches are not generated. This scratching of the thin film optical film causes unevenness in hardening and shrinkage of the hard coat layer and uneven application of the adhesive, so that the display defects are thought to occur.

Here, the scratches of the thin film optical film are minute scratches present at a level that can not be detected at the evaluation of the film surface of the optical film, and are generated by being inclined toward either the inner side of the film wound or the outer side of the wound film, It is presumed that a scratch on the support (for example, a belt) is transferred and formed in the film forming process by the solution casting method (solution casting method). Particularly, when a thin film optical film having a film thickness of 30 m or less is formed by the solution casting method, the solvent tends to evaporate on the belt, and the solvent ratio (residual solvent amount) It is considered that the scratches transferred from the belt by the drying shrinkage of the film in the process are not easily alleviated.

In order to suppress the display defects due to non-uniform shrinkage of the hard coating layer and uneven application of the adhesive, scratches which cause unevenness of curing shrinkage and uneven application of the adhesive may not be formed on both surfaces of the thin film optical film . However, when a thin film optical film having a thin film thickness is formed by the solution softening method, scratches transferred from the support are left on the surface of the thin film optical film at the time of softening of the thin film optical film as described above, Can not be formed.

Therefore, in order to suppress display defects in the liquid crystal display device, even if scratches transferred from the support are left on one side of the thin film optical film constituting the hard coating film, both of the hard shrinkage unevenness of the hard coat layer and the non- It is necessary to devise a method for suppressing the above- At this time, from the viewpoint of suppressing lowering of the production efficiency of the hard coating film, it is also necessary to easily determine the surface to which the hard coating layer should be applied in the thin film optical film, and to coat the hard coating layer on the thin optical film. Further, in the case where a plasticizer is contained in the thin film optical film, it is also necessary to suppress the bleed-out (ejection) of the plasticizer.

Japanese Patent Application Laid-Open No. 2006-212549 (paragraphs [0068], [0069], Figure 1, etc.)

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a thin film optical film capable of suppressing bleed-out of a plasticizer even when a scratch of a support is transferred onto a support- And it is an object of the present invention to provide a method for manufacturing a hard coating film which can easily determine the surface to which a hard coating layer is to be applied in a thin film optical film and suppress a decrease in production efficiency.

The above object of the present invention is achieved by the following constitution.

1. A coating composition comprising 1 to 20% by weight of a plasticizer having a property of being formed by a solution casting method and having a property of being localized on the support side at the time of casting in a film forming process and having a film thickness of 15 탆 Wherein the hard coat layer is applied to the side of the thin film optical film having the concentration of the fine silica particles larger than the average concentration of the thin film optical film over the entirety of the thin film optical film.

2. The method for producing a hard coat film as described in 1 above, wherein the plasticizer is a phosphoric acid plasticizer.

3. The method for producing a hard coat film according to 1 or 2, wherein the thickness of the hard coat layer is 0.5 占 퐉 or more and 10 占 퐉 or less.

4. If the plasticizer is a first plasticizer,

Wherein the thin film optical film contains at least 1% by weight of a second plasticizer different from the first plasticizer,

Wherein the total amount of the first plasticizer and the second plasticizer in the thin film optical film is 20% by weight or less.

5. The method for producing a hard coat film as described in 4 above, wherein the second plasticizer is a phthalic acid or polyhydric alcohol ester plasticizer.

According to the above production method, the hard coat layer is applied to a side of the thin film optical film having a film thickness of 15 mu m or more and 30 mu m or less, where the concentration of the silica fine particles is larger than the average concentration. This is because the concentration of the silica fine particles is increased because evaporation of the solvent occurs on the support during the film formation of the thin film optical film by the solution softening method. Therefore, in the thin film optical film, the side on the side where the concentration of the fine silica particles is large becomes the side opposite to the support on flexing. Since the hard coat layer is coated on this surface, the hard coat layer is not affected by scratches on the support at the time of film formation. This can suppress the hardening shrinkage unevenness of the hard coat layer. In addition, since the fine silica particles are not dissolved in a solvent, it becomes easy to optically discriminate the side of the thin optical film having a large concentration of fine silica particles (the side opposite to the supporter at the time of softening) It does not require a long time to discriminate between. As a result, the production efficiency of the hard coating film can be prevented from being lowered.

When a hard coating film (a thin film optical film with a hard coating layer) is adhered to a member (for example, a polarizing film in a liquid crystal display device) whose surface is to be protected, On the side opposite to the hard coat layer. This surface is the side of the support when the thin film optical film is formed, and if there is a scratch on the support, scratches on the support are transferred onto the coated surface of the adhesive. However, since the plasticizer is unevenly distributed on the surface side of the thin film optical film, flexibility is imparted to the surface side by the plasticizer. As a result, scratches on the coated surface are easily alleviated, so that occurrence of nonuniform coating of the adhesive on the coated surface can be suppressed, and adhesion failure can be suppressed.

At this time, even if a hard coat layer is formed on the opposite side (on the side where the plasticizer is localized) by applying an adhesive to the side of the thin film optical film where the concentration of fine silica particles is large, the hardening shrinkage unevenness of the hard coat layer can not be suppressed . This is presumably because the non-uniformity of curing shrinkage of the hard coat layer is more affected by the scratches of the thin film optical film than the unevenness of the application of the adhesive. However, in the above-mentioned production method, since the hard coat layer is formed on the side of the side where the concentration of fine silica particles is large (the side where the scratches on the support are not transferred), the hardness of the hard coat layer and the unevenness of application of the adhesive can be suppressed . Therefore, when the hard coating film produced by the above production method is applied to, for example, a polarizing plate of a liquid crystal display device (when the hard coating film is attached to the polarizing film of the polarizing plate), display defects can be suppressed .

When the amount of the plasticizer contained in the thin film optical film is less than 1% by weight, flexibility on the side of the adhesive application side is lowered, and it becomes difficult to suppress nonuniform application of the adhesive. On the other hand, when the amount of the plasticizer is more than 20% by weight, bleeding out easily occurs. Therefore, when the thin film optical film contains the plasticizer in an amount of 1 to 20% by weight, it is possible to suppress the display defects due to uneven application of the adhesive while suppressing the bleed-out.

1 is a cross-sectional view schematically showing an example of a cellulose ester film producing apparatus as a thin film optical film according to an embodiment of the present invention.
2 is a cross-sectional view showing a schematic structure of a liquid crystal display device to which a hard coating film using the cellulose ester film is applied.
3 is an explanatory view for explaining the A side and the B side of the cellulose ester film.
Fig. 4 is a cross-sectional view schematically showing the configuration of a main portion of a polarizing plate of the liquid crystal display device.

Hereinafter, embodiments for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

<Hard Coating Film>

The hard coating film of this embodiment is formed by forming a hard coating layer on one side of a thin film optical film having a film thickness of 15 mu m or more and 30 mu m or less.

(Hard coat layer)

The hard coating layer according to the present embodiment is preferable because it contains an active ray hardening resin because of its excellent mechanical strength (scratch resistance, pencil hardness). That is, it is a layer mainly composed of a resin which undergoes a crosslinking reaction by irradiation with active rays (also referred to as active energy rays) such as ultraviolet rays or electron rays. As the active ray hardening resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the active ray hardening resin layer is formed by irradiating an active ray such as ultraviolet rays or electron rays. Examples of the active ray curable resin include ultraviolet ray curable resin and electron ray curable resin. Representative examples of the active ray curable resin include a resin which is cured by irradiation with ultraviolet rays because it has excellent mechanical strength (scratch resistance, pencil hardness). Examples of the ultraviolet curable resin include ultraviolet curable acrylate resin, ultraviolet curable urethane acrylate resin, ultraviolet curable polyester acrylate resin, ultraviolet curable epoxy acrylate resin, ultraviolet curable polyol acrylate resin, Curable epoxy resin and the like are preferably used, and among them, an ultraviolet curable acrylate resin is preferable.

As 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 methacryloyl groups in the molecule. Examples of the monomer of polyfunctional acrylate include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylol Pentaerythritol triacrylate, pentaerythritol triacrylate, pentaerythritol triacrylate, pentaerythritol triacrylate, pentaerythritol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, Ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerin triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol penta Acrylic Diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol dimethacrylate, Trimethylol propane trimethacrylate, trimethylol ethane trimethacrylate, tetramethylol methane trimethacrylate, tetramethylol methane tetramethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol dimethacrylate, But are not limited to, styrene dimethacrylate, styrene dimethacrylate, styrene dimethacrylate, pentaerythritol triacrylate, stearyl dimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol tetramethacrylate, glycerin trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, Pentamethacrylate, dipentaerythritol hexamethacrylate, active energy Curing isocyanatomethyl may be preferably include isocyanurate derivatives.

The hard coat layer according to the present embodiment is preferable in that it contains an active energy ray-curable isocyanurate derivative in that the effect of suppressing the slidability between films becomes high. The active energy ray-curable isocyanurate derivative may be any compound having a structure in which at least one ethylenic unsaturated group is bonded to the isocyanuric acid skeleton. The active energy ray-curable isocyanurate derivative may be a compound having three or more ethylenic unsaturation A compound having an unsaturated group and at least one isocyanurate ring is preferable. The ethylenic unsaturated group is preferably an acryloyl group, a methacryloyl group, a styryl group or a vinyl ether group, more preferably a methacryloyl group or an acryloyl group, and particularly preferably an acryloyl group.

In the formula, L ² is a divalent linking group, preferably a substituted or unsubstituted alkyleneoxy group or polyalkyleneoxy group having 4 or less carbon atoms bonded with a carbon atom to an isocyanurate ring, particularly preferably an alkyl And each may be the same or different. R ² represents a hydrogen atom or a methyl group, and may be the same or different. Specific compounds represented by the formula (1) are shown below, but are not limited thereto.

As other compounds, isocyanuric acid diacrylate compounds and isocyanuric acid ethoxy-modified diacrylates represented by the following general formula (2) are preferable.

Other examples include ε-caprolactone-modified active energy ray-curable isocyanurate derivatives, specifically, compounds represented by the following formula (3).

_One of R ₁ to R ₃ in the chemical structural formula is bonded to a functional group represented by the following a, b, and c, but at least one of R ₁ to R ₃ is a functional group of b.

a: -H, or - (CH ₂ ) n -OH (n = 1 to 10), preferably n = 2 to 6)

_{b: - (CH 2) nO-} (COC 5 H 10) m-COCH = CH 2 (n = 1 to 10), preferably n = 2 to 6, m = 2 to 8)

(wherein n is an integer of 1 to 10), preferably n = 2 to 6, and c: - (CH ₂ ) nOR wherein R is a (meth) acryloyl group.

Specific compounds represented by the general formula (3) are shown below, but are not limited thereto.

Commercially available products of the isocyanuric acid triacrylate compounds include, for example, A-9300 manufactured by Shin-Nakamura Chemical Industry Co., Ltd., and the like. Commercially available products of isocyanuric acid diacrylate compounds include ARONIX M-215 manufactured by Toagosei Co., Ltd., and the like. Examples of the mixture of the isocyanuric acid triacrylate compound and the isocyanuric acid diacrylate compound include Aronix M-315 and Aronix M-313 manufactured by Toagosei Co., Ltd. Active energy of? -caprolactone denaturation As the isocyanurate derivative of the hardening type,? -caprolactone-modified tris- (acryloxyethyl) isocyanurate A-9300-1CL manufactured by Shin Nakamura Kagaku Kogyo Co., Aronix M-327 manufactured by Toagosei Co., Ltd., and the like, but the present invention is not limited thereto.

These commercially available products include Adeka Optomer N series, Sun Rad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Chemical Industries, N-ester A-2, N-3, N-3, N-3, N-3, N-3, NK-ester ATM-35E, NK ester A-DOG, NK ester A-IBD-2E, A-9300, A-9300-1CL (manufactured by Shin Nakamura Kagaku Kogyo Co., ), PE-3A (Kyoe Shagaku), and the like. These active ray curable resins may be used singly or in combination of two or more kinds. The viscosity of the active ray curable resin at 25 占 폚 is preferably 20 mPa 占 퐏 or more and 2000 mPa 占 퐏 or less. By using such a resin having a low viscosity, a projection shape described later can be easily obtained. Specifically, when the viscosity of the resin is within the viscosity range, sufficient fluidity of the resin composition (composition containing the active ray-curable resin and the additive other than the solvent) is easily obtained in the drying step, and the projecting shape can be easily obtained.

The viscosity of the active ray-curable resin can be measured using a B-type viscometer under the condition of 25 ° C by mixing the resin with a disperser. A monofunctional acrylate may also be used.

Examples of the monofunctional acrylate include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxy ethyl acrylate, Acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, cyclohexyl acrylate, and the like can be used. . Such a monofunctional acrylate is available from Nippon Kasei Kogyo K.K., Shin Nakamura Kagaku Kogaku Co., Ltd., Osaka Yukigagaku Kogaku Co., Ltd., and the like.

In the case of using a monofunctional acrylate, it is preferable that the polyfunctional acrylate: monofunctional acrylate = 80: 20 to 98: 2 is contained in the mass ratio of the polyfunctional acrylate to the monofunctional acrylate.

(Photopolymerization initiator)

The hard coat layer preferably contains a photopolymerization initiator for accelerating curing of the active ray curable resin. As the amount of the photopolymerization initiator, it is preferable to contain the photopolymerization initiator: active ray curable resin in a mass ratio of 20: 100 to 0.01: 100. Specific examples of the photopolymerization initiator include alkylphenone, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone,? -Amyloxime ester, thioxanthone, and derivatives thereof, but are not limited thereto It is not.

Such a photopolymerization initiator may be a commercially available product, and examples thereof include IRGACURE 184, IRGACURE 907, IRGACURE 651 and the like, which are available from BASF Japan Co., Ltd., for example.

(Conductive agent)

The hard coat layer may contain a conductive agent for imparting antistatic properties. Preferable examples of the conductive agent include metal oxide particles or a π conjugated conductive polymer. An ionic liquid is also preferably used as the conductive compound.

(additive)

The hard coating layer has predetermined the difference in the contact angle (θ _Δ) for before and after the alkali treatment, water range in an easy point to control (e. G., 5 to 55 °), a silicone surfactant, a fluorine-based surface active agent, anionic surface active agent and a fluorine- -Siloxane graft compounds, fluorine-based compounds, acrylic copolymers and the like. In addition, a compound having an HLB value of 3 to 18 may be contained. The water repellency can be controlled by adjusting the kinds and the addition amounts of these additives, and it is easy to control _{? Δ} θ is within the above range, a hard coat layer shows hydrophilicity, when chwihaeteul volume into a roll, the slipping property between the hard coating film is suppressed, it can be obtained an effect of preventing the winding displacement.

Here, the difference (?) _Between the contact angles before and after the alkali treatment with water is a value obtained by subtracting the water hardness of the hard coat layer after alkali treatment at least under the following conditions at the contact angle (?) Of the hard coat layer with water before the alkali treatment of the hard coat film Of the contact angle with respect to water before and after the alkali treatment by subtracting the contact angle _? As the alkali treatment conditions, a hard coating film was immersed in a 2.5 mol / L potassium hydroxide solution at a temperature of 50 캜 for 120 seconds. For the contact angle with water, the sample was allowed to stand for 24 hours in an atmosphere at a temperature of 23 DEG C and a relative humidity of 55%. Thereafter, the sample was contacted with a contact angle meter (manufactured by Kyowa Kaimagaku Kagaku K.K.) under an atmosphere of a temperature of 23 DEG C and a relative humidity of 55% , Product name: DropMaster DM100), the contact angle with pure water one minute after dropping 1 μl of pure water was measured seven times, and the five measured values excluding the maximum value and the minimum value of the measured values were averaged.

The HLB value is a Hydrophile-Lipophile-Balance, hydrophilic-lipophilic-balance, and a value indicating the hydrophilicity or lipophilicity of the compound. The smaller the HLB value, the higher the lipophilicity, and the larger the HLB value, the higher the hydrophilicity. The HLB value can be obtained by the following equation.

HLB = 7 + 11.7 Log (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). According to the Griffin method, the HLB value = 20 × total food / molecular weight of the hydrophilic part (J. Soc. Cosmetic Chem., 5 (1954), 294). Specific compounds of the compounds having an HLB value of 3 to 18 are listed below, but the present invention is not limited thereto. () Indicates the HLB value.

Emulsion 102 (6.3), Emergene 103 (8.1), Emergene 104P (9.6), Emergen 105 (9.7), Emergene 106 (10.5), Emergene 108 Emergen 120 (15.3), Emergen 123P (16.9), Emergen 147 (16.3), Emergen 210P (10.7), Emergen 220 (14.2), Emergene 306P (9.4), Emergene 320P (13.9), Emergen 404 (8.8), Emergen 408 (10.0), Emergen 409PV (12.0), Emergen 420 (13.6), Emergen 430 (16.2), Emergene 705 (10.5), Emergene 707 Emergen 2020G-HA (13.0), Emergen 2025G (15.7), Emergene 1118S-70 (16.4) EMULGEN LS-114 (14.0) manufactured by Nisshin Chemical Industry Co., Ltd., Surfynol 104E (4), Surfynol 104H (4) manufactured by Nisshin Chemical Industry Co., , Surfynol 104A (4), Surfynol 104BC (4), Surfynol 104DPM (4), Surfynol 104PA (4), Surfynol 104PG-50 ), Surinol 440 (8), Surfynol 465 (13), Surfynol 485 (17), Surfynol SE (6), Shinetsu Chemical Industries Co., Ltd. KF-354 (10), KF-354L (16), KF-352 (7), KF-352 (7), X- KF-615A (10), KF-945 (4), KF-618 (11), KF-6011 (12), KF-6015 (4), KF-6004 (5).

Examples of the silicone surfactant include polyether-modified silicone, and KF series manufactured by Shin-Etsu Chemical Co., Ltd. and the like. Examples of acrylic copolymers include commercially available compounds such as BYK-350 and BYK-352 manufactured by Big Chem Japan Co., Ltd. Examples of the fluorochemical surfactant include Megafax RS series manufactured by DIC Corporation, Megafax F-444 Megafax F-556, and the like. The fluorine-siloxane graft compound refers to a compound of a copolymer obtained by grafting at least a polysiloxane and / or an organopolysiloxane containing a siloxane and / or an organosiloxane group to a fluorine resin. Such a fluorine-siloxane graft compound can be prepared by the method as described in the following Examples. Examples of commercially available products include ZX-022H, ZX-007C, ZX-049 and ZX-047-D manufactured by Fuji Kasei Kogyo Co., Examples of the fluorine-based compound include Optol DSX and Optol DAC manufactured by Daikin Industries, Ltd. These components are preferably added in an amount of 0.005 parts by mass or more and 5 parts by mass or less with respect to the solid component in the hard coating composition.

(Ultraviolet absorber)

The hard coat layer may further contain an ultraviolet absorber described in the cellulose ester film described later. When the hard coat film is composed of two or more layers, it is preferable that the hard coat layer contacting with the cellulose ester film contains an ultraviolet absorber.

The content of the ultraviolet absorber is preferably in the range of 0.01: 100 to 10: 100 in terms of the mass ratio of the ultraviolet absorber: hard coat layer constituent resin. When two or more layers are formed, the film thickness of the hard coat layer in contact with the cellulose ester film is preferably in the range of 0.05 to 2 mu m. The lamination of two or more layers may be formed as a simultaneous middle layer. The co-intermediate layer is formed by coating two or more hard coat layers on a substrate with wet on wet without a drying step to form a hard coat layer. In order to laminate the second hard coating layer wet on wet without being subjected to the drying process on the first hard coat layer, the lamination may be carried out in order by the extrusion coater, or the simultaneous intermediate layer may be formed on the slot die having the plurality of slits.

(solvent)

The hard coat layer is preferably formed by applying the above-mentioned hard coat layer-forming component to a hard coat layer composition by diluting the cellulose ester film with a solvent which swells or partially dissolves the cellulose ester film, applying it on a cellulose film in the following manner, drying and curing Do.

Examples of the solvent include ketones such as methyl ethyl ketone and acetone and / or acetic acid esters such as methyl acetate, ethyl acetate and butyl acetate, alcohols (ethanol and methanol), propylene glycol monomethyl ether, cyclohexanone and methyl isobutyl ketone . The coating amount of the hard coat layer is suitably in the range of 0.1 to 40 占 퐉, preferably 0.5 to 30 占 퐉, as the wet film thickness. The average dry film thickness is in the range of 0.01 to 20 mu m, preferably 0.5 to 10 mu m. More preferably in the range of 0.5 to 5 mu m.

The coating method of the hard coat layer may be a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method.

(Hard Coating Layer Forming Method)

After application of the hard coat layer composition, drying may be followed by curing (irradiation of active rays (also referred to as UV curing treatment)) and, if necessary, heat curing followed by UV curing. The heat treatment temperature after UV curing is preferably 80 DEG C or higher, more preferably 100 DEG C or higher, and particularly preferably 120 DEG C or higher. By performing the heat treatment after UV curing at such a high temperature, a hard coat layer having excellent film strength can be obtained.

The drying is preferably carried out at a high temperature of 90 deg. More preferably, the temperature of the rate drying section is 90 ° C or more and 125 ° C or less. By setting the temperature of the rate-decreasing drying zone at a high temperature, convection occurs in the coating film resin at the time of formation of the hard coat layer, and as a result, irregular surface roughness easily develops on the surface of the hard coat layer and is controlled by arithmetic average roughness Ra easy.

In general, it is known that the drying process changes from a constant state to a gradually decreasing state when the drying starts, and a region where the drying rate is constant is divided into a constant rate drying region and a region where the drying rate is decreased. It is called. In the constant-rate drying section, all the heat input is consumed in evaporation of the solvent on the surface of the coating film, and when the solvent on the surface of the coating film is decreased, the evaporation surface moves from the surface to the inside of the rate- Thereafter, the temperature of the coating film surface rises and approaches the temperature of the hot air, so that the temperature of the active ray curable resin composition is elevated and the resin viscosity is lowered and the fluidity is considered to increase.

As the light source for the 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 ultra high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp and the like can be used.

Irradiation conditions vary depending on each lamp, but the irradiation amount of the active ray is usually in the range of 50 to 1000 mJ / cm ² , preferably in the range of 50 to 300 mJ / cm ² . In addition, in the UV curing treatment, oxygen removal (for example, substitution with an inert gas such as nitrogen purge) may be performed in order to prevent reaction inhibition by oxygen. By adjusting the removal amount of the oxygen concentration, the cured state of the surface can be controlled. This makes it possible to control the presence state of the additive on the surface of the hard coat layer as a result of which it is easy to control the angle? _{Within the} above range. When irradiating the active line, it is preferable to perform the tension while applying a tensile force in the transport direction of the film, and more preferably, the tension is applied in the width direction. The tensile force to be imparted is preferably 30 to 300 N / m. The method of applying the tension is not particularly limited. The tension may be applied in the carrying direction on the back roller, or in the width direction or the biaxial direction in the tenter. As a result, a film excellent in planarity can be obtained.

(Surface shape)

The arithmetic mean roughness (Ra) of the hard coat layer is preferably in the range of 2 to 100 nm, particularly preferably in the range of 5 to 80 nm, since the slip property of the films is suppressed and the effect of preventing winding deviation is enhanced. In addition, the arithmetic average roughness (Ra) can be measured in accordance with JIS (Japanese Industrial Standards) B0601: 2001.

It is preferable that the height of the projection shape to be the arithmetic average roughness Ra is in the range of 2 nm to 4 mu m. Also, the width of the projection shape is within the range of 50 nm to 300 mu m, preferably within the range of 50 nm to 100 mu m.

The 10-point average roughness Rz of the hard coat layer is preferably 10 times or less than the center line average roughness Ra and the average range of curvature Sm is preferably 5 to 150 占 퐉, more preferably 20 to 100 占 퐉, The standard deviation of the convex height of the convex portion is preferably 0.5 占 퐉 or less, the standard deviation of the average convexity distance Sm based on the center line is preferably 20 占 퐉 or less, and the inclination angle of 0 to 5 degrees is preferably 10% or more. The arithmetic mean roughnesses Ra, Sm and Rz are values measured by an optical interference type surface roughness meter (NewView, manufactured by ZYGO) according to JIS B0601: 2001.

(Hayes)

The haze of the hard coating film is preferably in the range of 0.2 to 10% based on the visibility when used in an image display apparatus. The haze can be measured in accordance with JIS-K7105 and JIS K7136.

(Hardness)

The hard coating film of the present embodiment has a pencil hardness of not less than HB, more preferably not less than H, which is an index of hardness. HB, it is difficult to cause scratches in the polarizing plate forming process. The pencil hardness was measured by using a pencil for test prescribed by JIS S 6006 under the conditions of a weight of 500 g and a humidity of more than 2 hours at a temperature of 23 캜 and a relative humidity of 55% Is a value measured according to a pencil hardness evaluation method prescribed by JIS K5400.

<Cellulose Ester Film>

Next, the cellulose ester film as the thin film optical film of the present embodiment and the cellulose ester film bonded to the back side of the polarizing plate will be described.

Examples of the cellulose ester film (hereinafter also referred to as cellulose acetate film) include triacetylcellulose film, cellulose acetate propionate film, cellulose diacetate film, and cellulose acetate butyrate film. In addition, the cellulose ester film is obtained by using a combination of a polyester resin such as polyethylene terephthalate and polyethylene naphthalate, a polycarbonate resin, a polyethylene resin, a polypropylene resin, a norbornene resin, a fluororesin, a cycloolefin polymer, You can. Commercially available products of the cellulose ester film include, for example, Konica Minolta Tac KC8UX, KC4UX, KC8UY, KC4UY, KC6UA, KC4UA, KC4UE and KC4UZ (manufactured by Konica Minolta Opto). The refractive index of the cellulose ester film is preferably 1.45 to 1.55. The refractive index can be measured in accordance with JIS K7142-2008.

(Cellulose ester resin)

The cellulose ester resin (hereinafter also referred to as a cellulose ester) is preferably a lower fatty acid ester of cellulose. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having a carbon number of 6 or less and includes, for example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate and the like, cellulose acetate propionate , And cellulose acetate butyrate may be used.

Of the above-mentioned base materials, particularly preferred 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 acetalization (amount of bound acetic acid) of 51.0% to 56.0%. Commercially available products include L20, L30, L40 and L50 of Daicel Co., and Ca398-3, Ca398-6, Ca398-10, Ca398-30 and Ca394-60S available from Eastman Chemical Japan.

The cellulose triacetate preferably has an average degree of acetalization (amount of bonded acetic acid) of 54.0 to 62.5%, more preferably a cellulose triacetate having an average degree of acetatization of 58.0 to 62.5%.

Cellulose triacetate A having a number average molecular weight (Mn) of 125000 or more and less than 155000, a weight average molecular weight (Mw) of 265000 or more and less than 310000, a Mw / Mn of 1.9 to 2.1, an acetyl group substitution degree of 2.75 to 2.90 , Cellulose triacetate B having a number average molecular weight (Mn) of 155000 or more and less than 180,000, a weight average molecular weight (Mw) of 290000 or more and less than 360000, and Mw / Mn of 1.8 to 2.0.

Cellulose acetate propionate has an acyl group having 2 to 4 carbon atoms as a substituent, a substitution degree of an acetyl group as X, and a substitution degree of a propionyl group or a butyryl group as Y, the following formulas (I) and (II) at the same time.

(I) 2.6? X + Y? 3.0

(II) 0? X? 2.5

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

The degree of substitution of the acyl group can be measured in accordance with ASTM-D817-96, which is one of the standards formulated and published by the American Society for Testing and Materials (ASTM).

The number average molecular weight (Mn) and the weight average molecular weight (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

(Connected by three connectors manufactured by Showa Denko K.K.)

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

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

(Thermoplastic acrylic resin)

A cellulose ester film and a thermoplastic acrylic resin may be used in combination. It is preferable that the mass ratio of the thermoplastic acrylic resin to the cellulose ester resin is in the range of 95: 5 to 50:50 in the case of the thermoplastic acrylic resin: cellulose ester resin.

Acrylic resins also include methacrylic resins. The acrylic resin is not particularly limited, but it preferably contains 50 to 99 mass% of methyl methacrylate units and 1 to 50 mass% of other monomer units copolymerizable therewith. Examples of other copolymerizable monomers include alkyl methacrylates having an alkyl number of 2 to 18, alkyl acrylates having an alkyl number of 1 to 18 in an alkyl number, alpha, beta -unsaturated acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid , And itaconic acid, aromatic vinyl compounds such as styrene and? -Methylstyrene,?,? - unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide, N-substituted maleimide, and glutaric anhydride. These may be used singly or in combination of two or more.

Of these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, and 2-ethylhexyl acrylate are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer , Methyl acrylate or n-butyl acrylate are particularly preferably used. The weight average molecular weight (Mw) is preferably in the range of 80000 to 500000, and more preferably in the range of 1100000 to 500000.

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

(Fine particles)

In the cellulose ester film of the present embodiment, in order to improve handling properties, for example, acrylic particles, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, It is preferable to contain a matting agent such as inorganic fine particles or crosslinked polymers such as aluminum, magnesium silicate and calcium phosphate. The acrylic particle is not particularly limited, but is preferably a multi-layered acrylic granular composite. Of these, silicon dioxide is preferable in that the haze of the cellulose ester film 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.

The cellulose acetate film of the present embodiment preferably contains an ester compound or sugar ester represented by the following general formula (X) in terms of dimensional stability in environmental changes. First, the ester compound represented by the general formula (X) will be explained.

(X) B- (GA) n-G-B

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

Examples of the alkylene glycol component having 2 to 12 carbon atoms in the general formula (X) include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, Propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2- Ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1, Pentanediol 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2- 9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like, and these glycols are used singly or as a mixture of two or more kinds. Particularly, alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of its excellent compatibility with cellulose acetate. Examples of the aryl glycol component having 6 to 12 carbon atoms include hydroquinone, resorcin, bisphenol A, bisphenol F, and bisphenol. These glycols can be used alone or as a mixture of two or more thereof.

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 as a mixture of two or more . 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 and dodecanedicarboxylic acid, Species or a mixture of two or more species. 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 (compound (X-1) to (X-17)) of the compound represented by formula (X) are shown below, but the present invention is not limited thereto.

Next, the sugar ester compound will be described. The sugar ester compound is an ester other than a cellulose ester, and is a compound obtained by esterifying all or part of the OH group of a sugar such as the following monosaccharides, 2 sugars, 3 sugars or oligosaccharides. Examples of sugar include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, nisthos, 1F-fructosylnitose, stachyose, maltitol, lactitol, Oz, cellobiose, maltose, cellotriose, maltotriose, raffinose and kestose. In addition to these, gentiobiose, gentiootriose, gentiootetraose, xylotriose, galactosyl sucrose and the like can be mentioned. Of these compounds, compounds having a furanose structure and / or a pyranose structure are particularly preferable. Among these, sucrose, ketoose, nisthos, 1F-fructosylnitose, stachyose and the like are preferable, and sucrose is more preferable. As the oligosaccharide, maltooligosaccharide, isomaltooligosaccharide, fructooligosaccharide, galactooligosaccharide, and xylooligosaccharide are also preferably used.

The monocarboxylic acid used to esterify the sugar is not particularly limited, and known aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, aromatic monocarboxylic acids, 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 are acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanecarboxylic acid, But are not limited to, acetic acid, succinic acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, Saturated fatty acids such as carbonic acid, melissic acid and lactic 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 cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof. Examples of preferred aromatic monocarboxylic acids include benzoic acid, aromatic monocarboxylic acids having an alkyl group and an alkoxy group introduced into the benzene ring of benzoic acid, cinnamic acid, benzilic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid, tetralincarboxylic acid , And derivatives thereof. Specific examples thereof include xylyl acid, hemellitic acid, mesitylene acid, prenyl acid,? -Isoduryl acid, and diallyl acid. Examples of the aromatic monocarboxylic acid having two or more benzene rings M, p-anisic acid, creosotic acid, o-, m-, m-, or p-toluenesulfonic acid, m-toluenesulfonic acid, , p-homosalicylic acid, o-pyrocatecholic acid,? -resoric acid, vanillic acid, isobanilic acid, veratric acid, o-veratric acid, gallic acid, asaronic acid, mandelic acid, , Homo veratric acid, o-homo veratric acid, phthalic acid, and p-cumaric acid. However, benzoic acid is particularly preferred. Of the esterified ester compounds, an acetyl compound having an acetyl group introduced by esterification is preferable. Specific examples of the sugar ester compound that can be used in the present embodiment are shown below, but the present invention is not limited thereto.

The sugar ester compound is preferably a compound represented by the general formula (Y). Hereinafter, the compound represented by formula (Y) will be described.

&Lt; General Formula (Y) >

(Wherein R ₁ to R ₈ represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted arylcarbonyl group having 2 to 22 carbon atoms, and R ₁ to R ₈ are the same And may be different)

(Y-1) to (Y-23)), but is not limited thereto. In the following table, when the average degree of substitution is less than 8.0, any one of R ₁ to R ₈ represents a hydrogen atom.

In general formula (Y)

The substitution degree distribution can be adjusted to a desired degree of substitution by controlling the esterification reaction time or by mixing compounds having different degrees of substitution.

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 mass%, more preferably 5 to 25 mass%, more preferably 5 to 20 mass% Is particularly preferable.

(Other additives)

(Plasticizer)

The cellulose acetate film of the present embodiment may contain a plasticizer, if necessary. Examples of the plasticizer include, but are not limited to, polyvalent carboxylic acid ester plasticizers, glycolate plasticizers, phthalate ester plasticizers, phosphate ester plasticizers, polyhydric alcohol ester plasticizers, and acrylic plasticizers. Of these, an acrylic plasticizer is preferable in that it is easy to control the cellulose ester film by a retardation value described later.

The polyhydric alcohol ester plasticizer is preferably a plasticizer comprising an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and has an aromatic ring or a cycloalkyl ring in the molecule. Preferably 2 to 20, aliphatic polyhydric alcohol esters. Specific examples of the polyhydric alcohol ester-based plasticizer are shown below, but are not limited thereto.

The glycolate-based plasticizer is not particularly limited, but alkyl phthalyl alkyl glycolates are preferably used. Alkyl phthalyl alkyl glycolates include, for example, methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, Ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl Glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octylphthalyl methyl glycolate, and octylphthalyl ethyl glycolate.

Examples of the phthalate ester plasticizers include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dicyclohexyl terephthalate, .

Examples of the phosphate ester plasticizer include triphenyl phosphate (TPP), tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, butyl phenyl diphenyl phosphate (BDP) And the like.

The polycarboxylic acid ester plasticizer is a compound comprising an ester of a polyvalent carboxylic acid and an alcohol having a valence of 2 or more, preferably 2 to 20, Specific examples include triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyltriphenyl citrate, acetyl tribenzyl citrate, Dibutyl, diacetyl dibutyl tartrate, tributyl trimellitate, tetrabutyl pyromellitate, and the like, but are not limited thereto.

The acrylic plasticizer is preferably an acrylic polymer, and the acrylic polymer is preferably a homopolymer or copolymer of acrylic acid or methacrylic acid alkyl ester. Examples of the monomer of the acrylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate (n-, i-), acrylonitrile (n-, i-), myristyl acrylate (n- , i-), acrylic acid (2-ethylhexyl), acrylic acid (? -caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl) Hydroxybutyl), acrylic acid (2-methoxyethyl), acrylic acid (2-ethoxyethyl) and the like, or the acrylic acid ester is replaced with methacrylic acid ester . The acrylic polymer is a homopolymer or a copolymer of the above monomers, and preferably has 30 mass% or more of acrylic acid methyl ester monomer units and more preferably 40 mass% or more of methacrylic acid methyl ester monomer units. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.

(Ultraviolet absorber)

The cellulose acetate film of this embodiment may contain an ultraviolet absorber. Since the ultraviolet absorbent absorbs ultraviolet rays of 400 nm or less, the durability can be improved. The ultraviolet absorber preferably has a transmittance at a wavelength of 370 nm of 10% or less, more preferably 5% or less, further preferably 2% or less. Specific examples of ultraviolet absorbers include, but are not limited to, oxybenzophenone compounds, benzotriazole compounds, salicylic ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, , And inorganic powders.

More specifically, for example, 5-chloro-2- (3,5-di-sec-butyl-2-hydoxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol- ) -6- (straight chain and branched dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone and 2,4-benzyloxybenzophenone. For example, tinuvin such as Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327 and Tinuvin 328 available from BASF Japan is preferably used. .

The ultraviolet absorber preferably used is a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, or a triazine ultraviolet absorber, particularly preferably a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, or the like.

In addition, a discotic compound such as a compound having a 1,3,5-triazine ring is also preferably used as an ultraviolet absorber. As the ultraviolet absorber, a polymer ultraviolet absorber can be preferably used, and a polymer-type ultraviolet absorber is preferably used.

As the benzotriazole ultraviolet absorber, TINUVIN 109 (octyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro- 2H-benzotriazole -2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl- Pyranate), 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, TINUVIN 400 (2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl ) -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) , Reaction product of 5-triazine and (2-ethylhexyl) -glycidic acid ester) and the like.

The ultraviolet absorber may be added by dissolving the ultraviolet absorber in an alcohol such as methanol, ethanol or butanol, or an organic solvent such as methylene chloride, methyl acetate, acetone or dioxolane or a mixed solvent thereof, ), Or may be added directly to the dope composition. In the case of not dissolving in an organic solvent such as an inorganic powder, it is dispersed in an organic solvent and cellulose acetate using a dissolver or a sand mill, and then added to the dope.

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

(Antioxidant)

The cellulose acetate film of the present embodiment may also contain an antioxidant (deterioration inhibitor). The antioxidant has a role of retarding or preventing the decomposition of the cellulose acetate film by halogen or a phosphoric acid of a phosphate-based plasticizer in the residual solvent amount in the cellulose acetate film. As the antioxidant, a hindered phenol-based compound is preferably used, and examples thereof include 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol- Bis (n-octylthio) -6- (4-hydroxy-3,5-di-t-butyl-4-hydroxyphenyl) propionate] Di-t-butyl anilino) -1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di -t-butyl-4-hydroxybenzyl) -isocyanurate and the like. The amount of these compounds to be added is preferably 1 ppm to 10000 ppm, more preferably 10 ppm to 1000 ppm, in mass ratio with respect to the cellulose acetate film.

(fault)

It is preferable that the cellulose ester film has a defect of not less than 5 占 퐉 in diameter / 10 cm or less. More preferably 0.5 pieces / square 10 cm or less, further preferably 0.1 pieces / square 10 cm or less. Herein, the defect means defects such as voids (foaming defects) in the film caused by the rapid evaporation of the solvent in the step of drying the solution film, foreign matter (foreign matter defect) in the film due to the foreign matter mixed in the film forming solution, It refers to the warrior and scratch of the scratch. The diameter of the defect refers to the diameter of the defect when the defect is circular, and when the defect is not circular, the range of defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of the circumscribed circle) is determined.

The range of the defect is the shadow size when the defect is observed in the transmitted light of the differential interference microscope when the defect is bubble or foreign matter. When the defect is a change in surface shape such as a transfer of a roller flaw or a scratch, the defect can be observed as reflected light of a differential interference microscope, and the size thereof can be confirmed.

If the number of defects is more than 1/10 cm per side, for example, if tension is applied to the film at the time of processing in a subsequent process or the like, the film breaks from the defect point as a starting point, and productivity may be deteriorated. When the diameter of the defect is 5 占 퐉 or more, defects can be visually confirmed by observing the polarizing plate or the like, and a bright spot may be generated when the film is used as an optical member. Further, even when the defects can not be visually confirmed, the coating film can not be uniformly formed when the hard coat layer is formed, and coating may be omitted.

The base film preferably has an elongation at break of at least 10%, more preferably at least 20%, in at least one direction in accordance with JIS-K7127-1999. The upper limit of the elongation at break is not particularly limited, but is about 250% in practice. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter or foaming.

(Optical characteristics)

The cellulose ester film preferably has a total light transmittance of 90% or more, more preferably 93% or more. The practical upper limit is about 99%. The haze value is preferably 2% or less, and more preferably 1.5% or less. The total light transmittance and the haze value can be measured in accordance with JIS K7361 and JIS K7136.

Further, it is preferable that the in-plane retardation value (Ro) of the cellulose ester film is in the range of 0 to 5 nm and the retardation value (Rth) in the thickness direction is in the range of -10 to 10 nm. It is more preferable that Rth is in the range of -5 to 5 nm.

Ro and Rth are values defined in the following formulas (i) and (ii).

(I) Ro = (nx-ny) xd

(Ii) Rth = {(nx + ny) / 2-nz} xd

Ny is the index of refraction in the direction orthogonal to the slow axis in the base film surface, nz is the index of refraction in the thickness direction of the cellulose ester film, d is the refractive index of the cellulose ester film in the cellulose ester film, Thickness (nm), respectively)

The retardation can be obtained at a measurement wavelength of 590 nm under an environment of 23 DEG C and 55% RH (relative humidity) using, for example, KOBRA-21ADH (Oji Keisei Kikuchi). Use of a cellulose ester film controlled to the above retardation value is preferable because of its excellent visibility when used in an image display device such as a touch panel or a liquid crystal display device. The retardation can be adjusted by the type and amount of the above plasticizer, the film thickness of the cellulose ester film, and the stretching conditions.

(Formation of Cellulose Ester Film)

(Organic solvent)

The cellulose ester film of this embodiment is formed by the solution casting method (solution casting method). The organic solvent useful for forming the resin solution (dope composition) when the cellulose ester film is formed by the solution casting method can be used without limitation as long as it dissolves the cellulose ester resin and other additives at the same time. Examples of the chlorine-based organic solvent include methylene chloride and the non-chlorine-based organic solvent includes methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, Ethyl, 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- Propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol, and methylene chloride, methyl acetate, ethyl acetate and acetone are preferably used have. The solvent is preferably a dope composition obtained by dissolving a cellulose ester resin and other additives in a total amount of 15 to 45 mass%.

(Solution softening method)

In the solution casting method, there are a process of preparing a dope by dissolving a resin and an additive in a solvent, a process of softening a dope on a belt-shaped or drum-shaped metal support, a process of drying a flexible dope as a web, A step of stretching or peeling the peeled web, a step of drying the web, and a step of winding the finished cellulose ester film. Hereinafter, this will be described in more detail.

1 is a cross-sectional view schematically showing an example of an apparatus for producing a cellulose ester film as a thin film optical film according to the present embodiment. In Fig. 1, first, in a melting furnace 1, for example, a resin such as a cellulose ester is dissolved in a mixed solvent of a good solvent and a poor solvent, and additives such as a plasticizer and an ultraviolet absorber are added to prepare a dope do.

Subsequently, a metal support body made of a rotary-driven stainless steel endless belt for feeding the dope adjusted in the melting furnace 1 to the flexible die 3 through a conduit through the pressurized metering gear pump 2, (Soft film) formed thereby is brought into contact with the metal support 6 at a flexible position on the flexible substrate 6 at the flexible position. The endless belt as the metal support 6 is held by a pair of front and rear drums 5, 5 and a plurality of intermediate rolls (not shown). (Not shown) for applying tension to the endless belt is provided on one or both of the drums 5, 5 of the both end winding portions of the endless belt, whereby the endless belt is tensioned and used in a taut state do.

Instead of the endless belt, a rotary driving drum made of stainless steel and subjected to a hard chrome plating treatment on its surface is used as the metal supporting body 6, and the web is formed by softening the dope from the flexible die 3 on the rotary driving drum .

The dope softening by the flexible die 3 includes a doctor blade method for adjusting the film thickness of a flexible web by a blade, a reverse roll coater for adjusting the film thickness by a roll for reversing the flexible web, a method of using a pressure die . Among them, a method of using a pressure die is preferred because it is possible to adjust the slit shape of the holding portion and to make the film thickness uniform. The pressure die includes a coated hanger die and a T die, all of which can be preferably used.

In the solution casting method, the solid content concentration of the dope such as cellulose ester which is flexible from the flexible die 3 onto the metal support 6 is preferably 15 to 30% by weight. If the solid concentration of the dope is less than 15% by weight, sufficient drying can not be carried out on the metal support 6, and part of the web remains on the metal support 6 upon peeling, leading to contamination (for example, belt contamination) . If the solid concentration of the dope exceeds 30%, the viscosity of the dope becomes high, the clogging of the filter is accelerated in the dope adjusting step, the pressure increases during the softening of the dope onto the metal support 6, There is a possibility that there will be no.

In this manner, the strength of the gel film (film strength) is increased by facilitating the drying of the dope softened on the surface of the metal support 6 until peeling off.

The residual amount of the residual solvent in the web 9 is preferably not more than 150 wt% on the metal support 6 in order to dry and solidify the web 9 until the peelable film strength is reached by the peeling roll 8 from the metal support 6. [ , And more preferably 80 to 120% by weight. The web temperature at which the web 9 is peeled off from the metal support 6 is preferably 0 to 30 占 폚. The temperature of the web 9 is rapidly lowered by the evaporation of the solvent from the side close to the metal support 6 immediately after peeling from the metal support 6 and the volatile component such as steam or solvent vapor in the atmosphere is condensed The web temperature at the time of peeling is more preferably 5 to 30 占 폚.

Here, the residual solvent amount can be expressed by the following formula.

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

In the formula, M is the weight of the web at any point in time, and N is the weight of the weight M when dried at 110 ° C for 3 hours.

The web 9 formed by the flexible dope on the metal support 6 is heated on the metal support 6 and the solvent is removed from the metal support 6 by the separation roll 8 until the web 9 becomes peelable &Lt; / RTI &gt; In order to evaporate the solvent, there are a method of blowing air from the side of the web 9, a method of transferring heat from the back surface of the metal support 6 by liquid, a method of transferring heat from the front and back by radiant heat, Or may be used in combination.

It is preferable that the peeling tension when peeling the web 9 from the metal support 6 by the peeling roll 8 is greater than the peeling force obtained by peeling force measurement such as JIS Z 0237. [ This is performed in a state where the peeling strength is increased for stabilization because the peeling position may be on the downstream side when the peeling tension is made equal to the peeling force obtained by the JIS measurement method at the time of high-speed film formation. However, even when the film was formed with the same peeling tension in the process, it was also confirmed that when the peeling force by the JIS measuring method was lowered, the deviation of the cross-Nicole transmittance (CNT) of the film was greatly reduced.

The peeling tension value in the step is usually 50 to 250 N / m.

The web 9 is peeled off by the peeling roll 8 after the web 9 is dried and solidified until the peelable film strength is reached on the metal support 6 and then the web 9 is peeled off from the tenter 10 of the stretching step The web 9 is stretched.

In the stretching step, as the film for a liquid crystal display device, a tenter system in which both side edges of the web 9 are fixed with clips or the like and stretched is preferable because it improves the planarity and dimensional stability of the film.

The amount of the residual solvent in the web 9 immediately before entering the tenter 10 in the stretching process is preferably 1 to 10% by weight. The elongation of the web in the tenter 10 of the stretching process is preferably 1 to 100%, more preferably 3 to 80%, and further preferably 3 to 60%.

The temperature of the hot air blown out from the hot air blowing slit opening in the tenter 10 is 100 to 200 占 폚, preferably 110 to 190 占 폚, and more preferably 115 to 185 占 폚.

After the tenter 10 of the stretching process, a drying device 11 is installed. In the drying apparatus 11, the web 9 is meandered by a plurality of transport rolls arranged in a zigzag shape in side view, and the web 9 is dried therebetween. The film transporting tension in the drying apparatus 11 is affected by the physical properties of the dope, the amount of residual solvent in the film transportation process, the drying temperature, and the like. The film transport tension during drying is 10-300 N / m width, To 270 N / m width is more preferable.

The means for drying the web (film) 9 is not particularly limited, and generally, hot air, infrared rays, heating rolls, microwaves or the like are used. For example, it is preferable to dry with hot air from the standpoint of simplicity, and for example, it is dried by the drying wind 12 blown in at the warm air inlet of the drying device 11 and exhaust wind is discharged from the outlet of the drying device 11 And dried. The temperature of the drying air 12 is preferably from 40 to 160 DEG C, more preferably from 50 to 160 DEG C because the flatness and dimensional stability are improved.

The process from softening to post-drying may be performed in an air atmosphere or in an inert gas atmosphere such as nitrogen gas. In this case, it goes without saying that the drying atmosphere is carried out in consideration of the explosive limit concentration of the solvent.

The optical film (F) conveyed after completion of the drying process in the drying device (11) is wound by a winding device (13) to obtain a wound web of optical film. When the residual solvent amount of the dried film is 0.5 wt% or less, preferably 0.1 wt% or less, a film having good dimensional stability can be obtained.

As a method of winding the film, there is a method of controlling the tension such as a constant torque method, a constant tension method, a taper tension method, and an internal stress constant program tension control method, which are generally used. do. The bonding of the film to the winding core (wrapping core) may be either a double-sided adhesive tape or a single-sided adhesive tape.

The film thickness after drying of the optical film (F) such as cellulose ester is preferably 15 占 퐉 or more and 30 占 퐉 or less from the viewpoint of thinning of the liquid crystal display device. Here, the film thickness after drying refers to the film thickness in a state where the residual solvent amount in the optical film (F) is 0.5% by weight or less.

If the film thickness of the optical film (F) after winding is too thin, for example, the strength required for a protective film for a polarizing plate may not be obtained. On the other hand, if the film thickness of the optical film (F) is too large, the advantage of thinning of the resin film such as a conventional cellulose ester is lost. The control of the film thickness is carried out by controlling the dope concentration, the amount of the pump feed liquid, the gap of the separating member slit of the flexible die 3, the extrusion pressure of the flexible die 3, the speed of the metal support 6, good. Further, as means for making the film thickness uniform, it is preferable to adjust the film thickness detection means by feeding back the programmed feedback information to each of the apparatuses.

(Physical Properties of Cellulose Ester Film)

The film thickness of the cellulose ester film in the present embodiment is preferably 15 占 퐉 or more and 30 占 퐉 or less as described above. Further, the width of the cellulose ester film is preferably 1 to 4 m. If it exceeds 4 m, it becomes difficult to transport.

The length of the cellulose ester film is preferably 500 to 10,000 m, more preferably 1000 to 8000 m. By setting the length to be within the above range, it is possible to improve the processability in coating of the hard coat layer or the like and handling property of the cellulose ester film itself.

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

Further, the contact angle of the cellulose ester film with respect to water before the alkali treatment is generally in the range of 40 to 80, and preferably 50 to 70. The contact angle with water after the alkali treatment may vary depending on the alkali treatment conditions, but is generally 10 to 60 degrees, preferably 20 to 60 degrees. The contact angle with respect to water is a value measured in accordance with the method described in the method for measuring the contact angle of the hard coat layer with respect to water.

It is presumed that the contact angle of the hard coat layer with water is lowered by the alkali treatment to be close to the contact angle with water of the cellulose ester film so that the hydrophilic layers are laminated to each other and the effect of preventing the winding displacement is obtained. As the alkali treatment method, the cellulose ester film is immersed in an alkali solution, followed by washing with water. After the alkali treatment, neutralization may be carried out in the acidic water process, followed by washing with water and drying.

Examples of the alkali solution include potassium hydroxide solution and sodium hydroxide solution. The concentration of the hydroxide ion is preferably in the range of 0.1 to 5 mol / L, more preferably in the range of 0.5 to 3 mol / L. The temperature of the alkali solution is preferably in the range of 25 to 90 占 폚, and more preferably in the range of 40 to 70 占 폚. The alkali treatment time is in the range of 5 seconds to 5 minutes, preferably 30 seconds to 3 minutes.

&Lt; Other layer >

In the hard coating film of this embodiment, other layers such as an antireflection layer and a conductive layer can be formed.

<Antireflection layer>

The hard coating film of the present embodiment can be used as an antireflection film having a function of preventing reflection of external light by forming an antireflection layer on the hard coat layer.

It is preferable that the antireflection layer is formed in consideration of the refractive index, the film thickness, the number of layers, the order of layers, and the like so that the reflectance is reduced by optical interference. It is preferable that the antireflection layer is formed by combining a low refractive index layer having a refractive index lower than that of the protective film or a high refractive index layer and a low refractive index layer having a refractive index higher than that of the protective film. Particularly preferably, the antireflection layer is composed of three or more refractive index layers and three layers having different refractive indexes on the support side are referred to as a middle refractive index layer (a layer having a higher refractive index than the support and a refractive index lower than that of the high refractive index layer) / a high refractive index layer / And a low refractive index layer in this order. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used. As the layer configuration, the following structure is conceivable, but the present invention is not limited thereto.

Cellulose ester film / hard coat layer / low refractive index layer

Cellulose ester film / hard coat layer / high refractive index layer / low refractive index layer

Cellulose ester film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer

Hard coat layer / cellulose ester film / hard coat layer / low refractive index layer

Hard coat layer / cellulose ester film / hard coat layer / high refractive index layer / low refractive index layer

Hard coating layer / cellulose ester film / hard coating layer / medium refractive index layer / high refractive index layer / low refractive index layer

Low Refractive Index Layer / Hard Coating Layer / Cellulose Ester Film / Hard Coating Layer / Low Refractive Index Layer

(Low refractive index layer)

The low refractive index layer preferably contains silica-based fine particles and the refractive index thereof is preferably in the range of 1.30 to 1.45 at a temperature of 23 캜 and a wavelength of 550 nm.

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

As the composition for forming the low refractive index layer, it is preferable that the silica-based fine particles have at least one outermost layer and at least one porous or hollow particle inside. Particularly, it is preferable that the particles having the respective outer layers and the inside of which is porous or hollow are hollow silica-based fine particles.

The composition for forming a low refractive index layer may also contain an organic silicon compound represented by the following formula (OSi-1), a hydrolyzate thereof, or a polycondensate thereof.

(OSi-1): Si (OR) ₄

In the formulas, R represents an alkyl group having 1 to 4 carbon atoms. Specific examples of the organic silicon compound represented by the general formula include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and the like.

In addition, a solvent, a silane coupling agent, a curing agent, a surfactant and the like may be added to the composition for forming a low refractive index layer, if necessary. Further, the composition for forming a low refractive index layer preferably contains a compound having a thermosetting property and / or a photo-curability mainly comprising a fluorine-containing compound containing fluorine atoms in a range of 35 to 80 mass% and containing a crosslinkable or polymerizable functional group . Specific examples thereof include a fluorine-containing polymer, a fluorine-containing sol-gel compound, and the like. Examples of the fluorine-containing polymer include hydrolysates of perfluoroalkyl group-containing silane compounds [for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane], dehydration condensates A fluorine-containing copolymer having a fluorine-containing monomer unit and a crosslinking reactive unit as a constituent unit.

(High refractive index layer)

It is preferable that the refractive index of the high refractive index layer is adjusted to be in the range of 1.4 to 2.2 at 23 캜 and at a wavelength of 550 nm. The thickness of the high refractive index layer is preferably 5 nm to 1 탆, more preferably 10 nm to 0.2 탆, and most preferably 30 nm to 0.1 탆.

The refractive index of the high refractive index layer can be adjusted by adding metal oxide fine particles or the like. The refractive index of the metal oxide fine particles to be used is preferably 1.80 to 2.60, more preferably 1.85 to 2.50. The kind of the metal oxide fine particles is not particularly limited and is selected from among 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 kind of element may be used.

(Conductive layer)

The hard coating film may be formed by forming a conductive layer on the hard coat layer. As the conductive layer to be formed, a generally 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 a hard coating film by a vacuum deposition method, a sputtering method, an ion plating method, a solution coating method or the like. It is also possible to form a conductive layer by using an organic conductive material which is an electrically conductive π-conjugated system conductive polymer.

In particular, a conductive material containing any one of indium oxide, tin oxide, and indium tin oxide, which is excellent in transparency and conductivity and can be obtained at a relatively low cost, can be suitably used. Though the thickness of the conductive layer varies depending on the material to which it is applied, it can not be said to be uniform. However, considering the economical efficiency, the thickness is preferably not more than 1000 nm, Or more and 80 nm or less, preferably 70 nm or less. In such a thin film, interference fringes of visible light due to thickness irregularity of the conductive layer are hard to occur.

<Polarizer>

Next, a polarizing plate using the hard coating film of the present embodiment will be described. The polarizing plate can be manufactured by a general method.

For example, a fully saponified polyvinyl alcohol aqueous solution is applied to at least one surface of a polarizing film prepared by subjecting the hard coating film of the present embodiment to alkaline saponification treatment and then treating the hard coating film by immersion stretching in a iodine solution, .

The other surface of the polarizing film may be the hard coating film, or the cellulose ester film described above may be used. The film thickness of the cellulose ester film used on the other side is preferably in the range of 5 to 34 mu m from the viewpoint of adjusting the smoothness and the curl balance and further enhancing the effect of preventing the winding deviation.

A polarizing film (polarizer), which is a main component of the polarizing plate, is a device that passes only a polarizing wave in a certain direction. A typical polarizing film currently known is a polyvinyl alcohol polarizing film. The polarizing film is a polyvinyl alcohol- Dyed, and dyed with a dichroic dye. However, the present invention is not limited thereto.

As the polarizing film, a film obtained by forming a polyvinyl alcohol aqueous solution, uniaxially stretching it, dyeing it, dyeing it, uniaxially stretching it, and preferably durability treatment with a boron compound is used. The film thickness of the polarizing film is 5 to 30 탆, preferably 8 to 15 탆.

On one side of the polarizing film, one side of the hard coating film of this embodiment is bonded to form a polarizing plate. Preferably, it is bonded by an aqueous adhesive mainly composed of fully saponified polyvinyl alcohol or the like.

(Adhesive layer)

It is preferable that the pressure-sensitive adhesive layer used for one side of the film to be bonded to the substrate of the liquid crystal cell is not only optically transparent but also exhibits appropriate viscoelasticity and adhesive property.

Specific examples of the adhesive layer include adhesives such as an acrylic copolymer, an epoxy resin, a polyurethane, a silicone polymer, a polyether, a butyral resin, a polyamide resin, a polyvinyl alcohol resin, A film can be formed by a drying method, a chemical hardening method, a thermosetting method, a thermal melting method, a photo-curing method, or the like, and curing can be performed. Among them, the acrylic copolymer is most easily used because it is easy to control the physical properties of the adhesive, and is excellent in transparency, weather resistance and durability.

<Winding>

The thickness of the air layer held between the layers when the hard coating film, the cellulose ester film or the polarizing plate of the present embodiment is wound in a roll shape is preferably 0.5 to 10 탆, more preferably 1 to 5 탆. The air layer thickness t 'is a value obtained from an equation of t' = [{(D ² -d ² ) / 4L} -t]. D is the winding diameter, d is the winding core diameter, L is the winding length, and t is the film thickness, and the units are all 탆.

In addition, a method of winding a hard coating film or the like is a method in which a roll touches a film in front of a take-up shaft and winds the film, or when a film is wound on a take- A film wound section for winding the film on the take-up core by winding the film on the take-up core by rotating the take-up core, and a method for winding the film on the take-up core by periodically shifting the film on the take- And an oscillating winding method is employed. The thickness of the air layer can be controlled by adjusting the winding conditions (for example, adjusting the tension at the time of winding).

<Image Display Device>

The hard coating film of the present embodiment is preferable in that it is used in an image display device and exhibits excellent visibility (clearability). Examples of the image display device include reflection type, transmissive type, transflective type liquid crystal display devices, liquid crystal display devices of various driving systems such as TN type, STN type, OCB type, VA type, IPS type and ECB type, A display device, a plasma display, and the like. Of these image display devices, the hard coating film of the present embodiment is preferably used for a liquid crystal display device or a touch panel display device because it is excellent in high visibility.

Fig. 2 is a cross-sectional view showing a schematic configuration of the liquid crystal display device 20, which is an example of an image display device to which the hard coating film of the present embodiment is applied. The liquid crystal display device 20 is constituted by bonding a polarizing plate 22 to one surface of a liquid crystal cell 21 sandwiching a liquid crystal layer between two substrates and bonding a polarizing plate 23 to the other surface. Here, the side where the polarizing plate 22 is provided to the liquid crystal cell 21 is defined as a light output side (viewer side).

Cellulose ester films 41 and 42 are attached to both surfaces of the polarizing film 31 (polarizer) of the polarizing plate 22. The cellulose ester film 41 and 42 are attached to both surfaces of the polarizing film 32 (polarizer) 43 and 44, respectively. The hard coat layer 51 is formed on the surface of the cellulose ester film 41 located on the opposite side of the liquid crystal cell 21 from the cellulose ester film 41 · 42 of the polarizing plate 22 on one side. The cellulose ester film 41 and the hard coat layer 51 constitute the hard coat film 60 of the present embodiment. As the polarizing film 31 · 32, the cellulose ester films 41 to 44, and the hard coat layer 51, those described above can be used. In addition, another layer such as the above-described antireflection layer may be formed on the surface of the hard coat layer 51 of the hard coat film 60.

&Lt; Process for producing hard coating film >

In the present embodiment, the non-uniform shrinkage of the hard coat layer 51 in the hard coating film 60 and the unevenness in coating when the adhesive for bonding the polarizing film 31 to the cellulose ester film 41 are coated is suppressed The hard coat film 60 is produced by the following method.

In this embodiment, a cellulose ester film 41 as a thin film optical film having a film thickness of not less than 15 μm and not more than 30 μm is formed by a solution casting method, and a plasticizer A (a first plasticizer ) And fine silica particles as a matting agent.

The plasticizer A has a property of localizing on the side of the metal support 6 during the formation of the cellulose ester film 41 by the solution softening method. For example, the plasticizer A described above may be used as the phosphoric acid plasticizer (for example, TPP Or BDP). The plasticizer A is localized on the side of the metal support 6 because the side opposite to the metal support 6 of the film (web) is in contact with the air on the metal support 6 at the time of softening, The solvent tends to evaporate on the side opposite to the side of the support 6, and thus the plasticizer A dissolved in the solvent is shifted toward the metal support 6. [ In this embodiment, the plasticizer A is contained in an amount of 1 to 20% by weight with respect to the entire film. Hereinafter, the surface of the film after peeling that was on the metal support 6 side is referred to as B side, and the side opposite to the metal support 6 is referred to as A side. When the A side and the B side of the cellulose ester film 41 are distinguished from each other in the drawing, the side 41a (A side) and the side 41b (B side), respectively, as shown in Fig.

Since the fine silica particles are different from the plasticizer A and are not dissolved in the solvent, the fine silica particles are not shifted toward the side B due to the evaporation of the solvent on the metal support 6, and the concentration of the fine silica particles on the side A (For example, 0.1 to 1%) of the fine silica particles in the entire film. That is, in the formed cellulose ester film 41, the concentration of fine silica particles on the side of the A side is larger than the average concentration of the entire film.

In the present embodiment, the hard coat layer 51 is applied to the side of the surface A, that is, the side where the concentration of the silica fine particles is larger than the average concentration in the cellulose ester film 41 formed. The reason is as follows.

The B-face side of the cellulose ester film 41 thus formed is a face on the side where it contacts the metal support 6 at the time of film formation. If there is a scratch on the surface of the metal support 6, the scratch is transferred to the B-side. When the hard coat layer 51 is applied to the B surface, the hard and soft shrinkage of the hard coat layer 51 occurs in portions where scratches occur on the B surface and portions that are not formed on the B surface. On the other hand, the A-face side of the cellulose ester film 41 is on the side not contacting the metal support 6 at the time of film formation, and is not affected by the scratches on the surface of the metal support 6. In the present embodiment, since the hard coat layer 51 is applied to the side A of the cellulose ester film 41, the hard coat layer 51 applied due to scratches on the surface of the metal support 6 is not uniformly shrunk .

At this time, in discriminating the A side and the B side of the cellulose ester film 41, the components of the microscopic range of the cross section of the film are frequently analyzed to examine the material composition of the cross section, thereby determining the A side and the B side of the film The production time of the hard coating film 60 is reduced. Further, because of the effect of the plasticizer A, minute scratches on the B side are alleviated as described later, so it is difficult to determine whether or not the B side is visually recognized.

In this respect, since the fine silica particles are not dissolved in the solvent, it is easy to optically discriminate the A side on the side where the concentration of fine silica particles in the cellulose ester film 41 is large. Therefore, as in the present embodiment, the hard coat layer 51 is coated on the side of the cellulose ester film 41 where the concentration of the silica fine particles is larger than the average concentration, whereby the hard coat layer 51 is reliably formed on the A side (It is possible to prevent the hard coat layer 51 from being erroneously formed on the opposite side). As a result, the production efficiency of the hard coating film 60 can be suppressed from lowering. As for the dispersion state of the fine silica particles in the film, for example, a small slice of the upper layer is sampled from the optical film before coating, a tomographic photograph of the optical film is taken with a transmission electron microscope at a magnification of 5000 times, It can be easily confirmed by finding the projected area of the particle.

4 is a cross-sectional view schematically showing the configuration of the main part of the polarizing plate 22 described above. As shown in the figure, in order to manufacture the polarizing plate 22, the hard coating film 60 is laminated on the polarizing film 31 and the adhesive 71 (for example, an aqueous system containing a main component of fully saponified polyvinyl alcohol, etc.) The adhesive 71 is applied to the surface (the surface 41b of the cellulose ester film 41) opposite to the hard coat layer 51 in the hard coat film 60. In this case, The surface 41b is a surface on the side where the cellulose ester film 41 comes into contact with the metal support 6 at the time of forming the cellulose ester film 41. If the metal support 6 is scratched, / RTI &gt;

However, since the plasticizer A is localized on the B-face side (on the side of the face 41b) of the cellulose ester film 41, flexibility is imparted to the side of the face 41b by the plasticizer A. This makes it possible to suppress the occurrence of uneven application of the adhesive 71 on the surface 41b and to prevent the hard coating film 60 and the polarizing film 31 Can be suppressed.

Even if the hard coat layer 51 is formed on the B face side of the cellulose ester film 41 in view of the fact that the plasticizer A is unevenly distributed on the B face side and the surface 41b is flawed, The shrinkage non-uniformity of the cured product is thought to be suppressed. However, it has been found that the unevenness of the cured shrinkage can not be suppressed. It is considered that this is because the non-uniformity of curing shrinkage of the hard coat layer 51 is more affected by the scratches of the cellulose ester film 41 than the unevenness of the application of the adhesive 71.

In this embodiment, since the hard coat layer 51 is formed on the side A of the cellulose ester film 41 and the adhesive 71 is applied on the side B side as described above, the hardening coating shrinkage unevenness And the uneven application of the adhesive 71 can be suppressed at the same time. Therefore, when the hard coating film 60 produced by the above production method is applied to the polarizing plate 22 of the liquid crystal display device 20 (the hard coating film 60 is attached to the polarizing film 31 of the polarizing plate 22) , It is possible to suppress display defects from occurring.

When the amount of the plasticizer A contained in the cellulose ester film 41 is less than 1% by weight, the flexibility of the side of the application side (B side) of the adhesive 71 is lowered and it is difficult to suppress the uneven application of the adhesive 71 It becomes. On the other hand, when the amount of the plasticizer A is more than 20% by weight, bleeding-out of the plasticizer tends to occur easily. Therefore, by containing the plasticizer A in an amount of 1 to 20% by weight, the cellulose ester film 41 can suppress the display defects due to uneven application of the adhesive 71 while suppressing bleeding out.

Particularly, by using a phosphate plasticizer (for example, TPP, BDP) as the above plasticizer A, the plasticizer A is reliably localized on the metal support 6 side in the process of forming the cellulose ester film 41 And flexibility can be surely given to the surface 41b on the metal support 6 side to which the adhesive 71 is applied.

It is preferable that the thickness of the hard coat layer 51 applied to the side A of the cellulose ester film 41 is 0.5 占 퐉 or more and 10 占 퐉 or less. When the hard coat layer 51 is thinner than 0.5 탆, it becomes difficult to impart the hardness required for the hard coat layer 51. On the other hand, when the hard coat layer 51 is thicker than 10 탆, cracks tend to occur in the hard coat layer 51 when the hard coat layer 51 is wound around the winding core of the hard coat film 60. Therefore, when the thickness of the hard coat layer 51 is 0.5 占 퐉 or more and 10 占 퐉 or less, it is possible to suppress the occurrence of cracks during winding while imparting the hardness required for the hard coat layer 51. Further, when the thickness of the hard coat layer is 0.7 m or more and 9 m or less, it is more preferable that sufficient hardness is given to the hard coat layer 51 and cracks can be reliably suppressed.

Further, the cellulose ester film 41 may contain at least 1% by weight of plasticizer B (second plasticizer) different from the plasticizer A described above. In this case, the total amount of the plasticizer A and the plasticizer B in the cellulose ester film 41 is preferably 20% by weight or less.

Since the cellulose ester film (41) contains the plasticizer (B) in an amount of 1% by weight or more, flexibility is imparted to the entire cellulose ester film (41) to give flexibility to the whole film. Further, the total amount of the plasticizer A and the plasticizer B in the cellulose ester film 41 is 20% by weight or less, whereby bleeding out of at least one of the plasticizer A and the plasticizer B can be suppressed.

At this time, the plasticizer B is preferably the phthalate ester-based or polyhydric alcohol ester-based plasticizer described above. When such a plasticizer is used, the above effect of imparting flexibility to the entire film can be reliably obtained.

<Examples>

Hereinafter, an embodiment of the present embodiment will be described, but the present invention is not limited thereto. In the examples, &quot; part &quot; or &quot;% &quot; is used, and unless otherwise specified, "parts by mass" or "% by mass"

&Lt; Example 1 >

(Production of cellulose ester film)

· Adjustment of silicon dioxide dispersion

10 parts by mass of Aerosil R812 (manufactured by Nippon Aerosil Co., Ltd.)

(Average diameter of primary particles: 7 nm)

90 parts by mass of ethanol

The mixture was stirred in a dissolver for 30 minutes, and then dispersed with Manton-Gaulin. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed in a dissolver for 30 minutes to prepare a silicon dioxide dispersion diluted solution. And filtered through a fine particle dispersion diluent filter (ADVANTEK TOYO Co., Ltd .: polypropylene wind cartridge filter TCW-PPS-1N).

&Lt; Preparation of dope composition >

(Cellulose ester resin)

Cellulose triacetate A (cellulose triacetate synthesized by a linter surface, acetyl group degree of substitution 2.88, Mn = 140000) 90 parts by mass

(additive)

X-1 5 parts by mass

X-12 4 parts by mass

(Ultraviolet absorber)

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

(Fine particles)

Silicon dioxide dispersion diluted solution 4 parts by mass

(menstruum)

Methylene chloride 432 parts by mass

Ethanol 38 parts by mass

The solution was completely dissolved while stirring and heating. The solution was filtered using Azumi filter paper No. 24 manufactured by Azumi Co., Ltd. to prepare a dope (DOPF composition 1).

Subsequently, the dope was uniformly softened on a stainless steel band support as the metal support 6 by using a belt softening apparatus (production apparatus of Fig. 1). Then, in the stainless steel band support, the solvent was evaporated until the residual solvent amount became 100%, and the web was peeled off on the stainless steel band support. The web of the cellulose ester film was evaporated at 35 캜 by evaporation, and the film was slit to a width of 1.15 m and dried at a drying temperature of 140 캜 while being stretched by 1.15 times in the TD direction (width direction of the film) in the tenter. Thereafter, the inside of the drying apparatus 11 at 120 캜 was dried for 15 minutes while being conveyed by a plurality of rollers, slit at a width of 1.3 m, knurled at both ends of the film 10 mm in width and 5 탆 in height, And wound around a core to obtain a cellulose ester film. The film thickness of the cellulose ester film was 25 탆 and the winding length was 5000 m. The content of the fine silica particles (plasticizer A) in the cellulose ester film was 9% by weight, and the content of the phthalate ester plasticizer (plasticizer B) was 2% by weight. The phthalate ester plasticizer is the above-mentioned compounds (X-1) and (X-12).

Further, the drawing magnification in the MD direction calculated from the rotating speed of the stainless steel band support and the operating speed of the tenter was 1.01 times.

[Production of hard coating film]

The following hard coat layer composition was filtered with a polypropylene filter having a pore size of 0.4 占 퐉 on the A side of the above-prepared cellulose ester film, and the film was coated by using an extrusion coater. The coated layer was cured by irradiating the irradiated portion with an illuminance of 100 mW / cm ² and an irradiation amount of 0.2 J / cm ² using an ultraviolet lamp while nitrogen was purged so that the oxygen concentration became 1.0 vol% A hard coat layer having a thickness of 7 占 퐉 was formed and wound up to an air layer thickness of 4 占 퐉 to prepare a roll-shaped hard coat film.

As the determination of the A-plane and the B-plane of the cellulose ester film at this time, a slice of the cellulose ester film was taken, and a tomographic photograph of the cellulose ester film was taken with a transmission electron microscope having a magnification of 5000 times and the projected area of the particle By observing, it was easily judged that the side having a larger particle abundance was the A side.

&Quot; Hard Coat Layer Composition &quot;

&Lt; Preparation of fluorine-siloxane graft polymer >

Quot; indicates the commercial name of the material used for the production of the fluorine-siloxane graft polymer.

Radical Polymerizable Fluoropolymer (A): Cefral Coat CF-803 (hydroxyl value: 60, number average molecular weight: 15,000; manufactured by Central Glass Co., Ltd.)

One end Radical Polymerizable Polysiloxane (B): Sylar Plain FM-0721 (number average molecular weight 5,000; manufactured by Chisso Corporation)

Radical polymerization initiator: Perbutyl O (t-butylperoxy-2-ethylhexanoate, manufactured by Nippon Oil Co., Ltd.)

Curing agent: Sumerule N3200 (buret-type prepolymer of hexamethylene diisocyanate; manufactured by Sumitomo Bayer Urethane Co., Ltd.)

(Synthesis of radically polymerizable fluororesin)

(1554 parts by mass), xylene (233 parts by mass) and 2-isocyanatoethyl methacrylate (manufactured by Mitsubishi Chemical Corporation) were added to a glass reactor equipped with a mechanical stirrer, a thermometer, a condenser and a dry nitrogen gas inlet, 6.3 parts by mass), and the mixture was heated to 80 DEG C under a dry nitrogen atmosphere. After reacting at 80 DEG C for 2 hours and confirming disappearance of absorption of isocyanate by the infrared absorption spectrum of the sample, the reaction mixture was taken out to obtain a radically polymerizable fluororesin of 50 mass% via a urethane bond.

(Preparation of fluorine-siloxane graft compound)

(26.1 parts by mass), xylene (19.5 parts by mass) and n-butyl acetate (16.3 parts by mass) were added to a glass reactor equipped with a mechanical stirrer, a thermometer, a condenser and a dry nitrogen gas inlet, (1.8 parts by mass), methyl methacrylate (2.4 parts by mass), n-butyl methacrylate (1.8 parts by mass), lauryl methacrylate (1.8 parts by mass), 2-hydroxyethyl methacrylate (5.2 parts by mass) and perbutyl O (0.1 parts by mass) were charged and heated to 90 占 폚 in a nitrogen atmosphere, and then maintained at 90 占 폚 for 2 hours. And a solution of 35 mass% fluorine-siloxane graft compound having a weight average molecular weight of 171,000 was obtained by adding perbutyl O (0.1 part) and holding at 90 占 폚 for 5 hours. The weight average molecular weight was determined by GPC (gel permeation chromatography). The mass% of the fluorine-siloxane graft compound was determined by HPLC (liquid chromatography).

(Active ray curable resin)

Pentaerythritol tri / tetraacrylate

(NK Ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

                                                           70 parts by mass

30 parts by mass of trimethylolpropane triacrylate (A-TMPT, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

(Photopolymerization initiator)

6 parts by mass of Irgacure 184 (manufactured by BASF Japan Ltd.)

(additive)

Fluorine-siloxane graft compound (35 mass%) 2 mass parts

(solvent)

20 parts by mass of propylene glycol monomethyl ether

30 parts by mass of methyl acetate

70 parts by mass of methyl ethyl ketone

[Production of polarizer]

Using the hard coating film and the cellulose ester film prepared above, a polarizing plate was produced as follows.

(a) Production of a polarizing film

100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a degree of saponification of 99.95 mol% and a degree of polymerization of 2400 was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water, melt-kneaded, defoamed, Followed by melt extrusion. Thereafter, it was dried and heat-treated to obtain a PVA film.

The obtained PVA film had an average thickness of 25 탆, a water content of 4.4%, and a film width of 3 m. Then, the obtained PVA film was treated successively in the order of preliminary swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying and heat treatment in order to produce a polarizing film. That is, the PVA film was preliminarily swollen by immersing in water at 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 35 ° C for 3 minutes. Subsequently, uniaxial stretching was carried out six times in the aqueous solution at a boric acid concentration of 4% at a temperature of 50 DEG C under a tension applied to the film of 700 N / m, and the concentration of potassium iodide was 40 g / liter, the boric acid concentration was 40 g / / Liter in an aqueous solution at a temperature of 30 DEG C for 5 minutes. Thereafter, the PVA film was taken out, hot-air dried at a temperature of 40 占 폚, and heat-treated at a temperature of 100 占 폚 for 5 minutes. The obtained polarizing film had an average thickness of 13 탆, a transmittance of 43.0%, a polarization degree of 99.5% and a dichroism ratio of 40.1 for the polarizing performance.

(b) Production of polarizing plate

According to the following steps 1 to 4, a polarizing film, a cellulose ester film and a hard coating film were bonded to prepare a polarizing plate.

Step 1: The above-mentioned polarizing membrane 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.

Step 2: The cellulose ester film and the hard coat film were subjected to alkali treatment under the following conditions. Subsequently, in Step 1, the polarizing membrane was immersed in the polyvinyl alcohol adhesive solution. Excess adhesive adhered to the immersed polarizing film was lightly removed, and the polarizing film was laminated by interposing the cellulose ester film and the hard coating film, and wound up to an air layer thickness of 5 占 퐉 to prepare a roll-shaped polarizing plate.

(Alkali treatment)

Saponification process 2.5 mol / L-KOH 50 DEG C 120 sec

Washing process water 30 ℃ 60 seconds

Neutralization process 10 parts by mass HCl 30 占 폚 45 seconds

Washing process water 30 ℃ 60 seconds

After the saponification treatment, washing is carried out in the order of water washing, neutralization and washing, followed by drying at 100 ° C.

Step 3: The laminate was bonded to two rotating rollers at a pressure of 20 to 30 N / cm ² at a speed of about 2 m / min. At this time, care was taken to prevent air bubbles from entering.

Step 4: The sample prepared in Step 3 was dried for 5 minutes in a drier at a temperature of 100 占 폚 to prepare a roll-shaped polarizing plate.

<Fabrication of Liquid Crystal Display Device>

(Durability test evaluation)

The above-prepared roll-shaped polarizing plate was wrapped with an aluminum moisture-proof sheet and stored for 25 days in a thermostatic chamber at 50 DEG C and 80% relative humidity, assuming long-term transportation. After preservation for 25 days, an adhesive layer was formed as follows, and then incorporated into a liquid crystal display device to produce a liquid crystal display device.

(Adhesive layer)

A cellulose ester film of a polarizing plate was coated with a commercial acrylic pressure-sensitive adhesive so that the thickness after drying was 25 占 퐉 and dried in an oven at 110 占 폚 for 5 minutes to form a pressure-sensitive adhesive layer.

(Liquid crystal display device)

The polarizing plate on one side of the observer side was peeled off from the two pairs of polarizing plates provided with a liquid crystal layer in a 21.5 inch liquid crystal display (IPS226V-PN, manufactured by LG Electronics Japan Co., Ltd.) So that the pressure-sensitive adhesive layer and the liquid crystal cell glass were joined. The transmission axis of the viewer-side polarizing plate and the transmission axis of the backlight-side polarizing plate were orthogonal to each other, thereby fabricating a liquid crystal display device.

&Lt; Example 2 >

The same as Example 1 except that the content of the plasticizer A in the cellulose ester film of the hard coating film was 1 wt%.

&Lt; Example 3 >

The same as Example 1 except that the content of the plasticizer A in the cellulose ester film of the hard coating film was 20% by weight.

<Example 4>

Except that the film thickness of the cellulose ester film of the hard coating film was 15 占 퐉.

&Lt; Example 5 >

Except that the film thickness of the cellulose ester film of the hard coating film was 30 占 퐉.

&Lt; Example 6 >

The same as Example 1 except that the content of the plasticizer B in the cellulose ester film of the hard coating film was 1 wt%.

&Lt; Example 7 >

Except that the content of the plasticizer B in the cellulose ester film of the hard coating film was 3 wt%.

&Lt; Comparative Example 1 &

Except that the hard coat layer of the hard coat film was applied to the B face side of the cellulose ester film.

&Lt; Comparative Example 2 &

The same as Example 1 except that the plasticizer A was not contained in the cellulose ester film of the hard coating film.

&Lt; Comparative Example 3 &

Except that the content of the plasticizer A in the cellulose ester film of the hard coating film was 21 wt%.

&Lt; Comparative Example 4 &

Except that the film thickness of the cellulose ester film of the hard coating film was changed to 14 占 퐉.

"evaluation"

The display defects, the hard coat film strength, and the bleed out of the plasticizer were evaluated for the liquid crystal display. The results are shown in Table 1.

Here, the display defects of the liquid crystal display device were visually confirmed and evaluated based on the following criteria.

A: no display defect is detected at all.

○: Display defects were hardly detected.

?: Display defects are extremely rarely detected, but there is no problem in actual use.

X: Display defects are frequently detected and can not withstand use.

The strength of the hard coating film was evaluated by using a tensile tester based on the following criteria.

◎: Strong against tensile than target.

○: Strength to achieve the target sufficiently for tension.

△: Strength to attain the target for tension.

X: weak to tensile than target, unable to withstand use.

The bleed-out of the plasticizer was evaluated visually based on the following criteria after exposure to the durability conditions of high temperature and high humidity, the same as that of the formed cellulose ester film.

◎: Not at all.

○: Mostly not.

C: Very rarely, there is no problem in actual use.

X: Occurred frequently, and can not withstand use.

From Table 1, in Comparative Example 1, since the hard coat layer was applied to the B-face side of the cellulose ester film, display defects frequently occurred. In Comparative Example 2, the hard coat layer was applied to the A side of the cellulose ester film, but since the plasticizer A was not contained, display defects frequently occurred. In Comparative Example 3, since the content of the plasticizer A exceeded 20% by weight, bleeding-out of the plasticizer A frequently occurred. In Comparative Example 4, since the film thickness of the cellulose ester film was as thin as 14 占 퐉, the film strength was not secured.

On the other hand, in Examples 1 to 7, the content of the plasticizer A in the cellulose ester film was 1 to 20% by weight, the film thickness of the cellulose ester film was 15 to 30 탆, and the hard coat layer was coated on the side A of the cellulose ester film It can be seen that good results are obtained in all the evaluation items of display defects, film strengths, and bleed-outs in the liquid crystal display device.

Then, in the hard coat film of Example 1, the thickness of the hard coat layer applied on the cellulose ester film was changed. More specifically, in Examples 1-1 to 1-5, the thickness of the hard coat layer was set to 7 탆, 0.3 탆, 11 탆, 0.7 탆, and 9 탆, respectively. Other conditions are the same as those in the first embodiment described above. In the thus-prepared hard coating film, the hardness of the hard coating layer and occurrence of cracks were evaluated. The results are shown in Table 2.

Here, the hardness of the hard coat layer was evaluated by a pencil hardness test. Specifically, the hard coating layer side of the hard coating film was repeated five times using a pencil of each hardness using a weight of 500 g according to the pencil hardness evaluation method prescribed by JIS-K5400, using a test pencil specified by JIS-S6006 Scratches and scratches were measured for hardness up to one. Then, the hardness of the hard coat layer was evaluated based on the following criteria. The pencil hardness H was defined as the target hardness.

○: Target hardness can be sufficiently achieved.

△: target hardness can be achieved.

With regard to cracks in the hard coating layer, the samples of the hard coating film were wound around round bars each having a diameter of 5 mm and a diameter of 10 mm to observe the occurrence of cracks. When the hard coating film was wound around a round bar having a diameter of 10 mm, cracks did not occur in the hard coating layer in all of Examples 1-1 to 1-5. On the other hand, when the hard coating film was wound around a round bar having a diameter of 5 mm, cracks occurred in the hard coating layer in some of the hard coating films. The occurrence of cracks at this time is shown in Table 2 based on the following criteria.

A: When the hard coating film was wound around a round bar having a diameter of 5 mm, a wound mark was formed (no crack occurred in the hard coating layer).

DELTA: Cracks occurred in the hard coat layer when the hard coat film was wound around a round bar having a diameter of 5 mm.

It can be seen from Table 2 that the target hardness can be achieved when the thickness of the hard coat layer is 0.3 占 퐉 (see Example 1-2), and when the hard coat layer thickness is 0.7 占 퐉 or more (Examples 1-1, 1-3, 1-5), it is clear that the target hardness can be sufficiently achieved. If the thickness of the hard coat layer is not less than 0.5 탆 (0.3 탆 to 0.7 탆), it can be said that the target hardness can be sufficiently achieved.

On the other hand, in the case where the thickness of the hard coat layer was 11 μm (see Example 1-3), when the hard coat film was wound around a round bar having a diameter of 5 mm, cracks occurred in the hard coat layer. , It is necessary that the thickness of the hard coat layer is smaller than 11 mu m. When the thickness of the hard coat layer is 9 mu m or less, cracking of the hard coat layer can be reliably suppressed. When the thickness of the hard coat layer is 10 mu m or less (between 9 mu m and 11 mu m) It can be said that it is possible to do it.

As described above, in order to sufficiently attain the target hardness of the hard coat layer and to suppress the occurrence of cracks in the hard coat layer under severe winding conditions (winding on a round bar having a diameter of 5 mm), the thickness of the hard coat layer is more than 0.3 탆, Mu] m or less, more preferably 0.5 mu m or more and 10 mu m or less, and more preferably 0.7 mu m or more and 9 mu m or less.

Subsequently, the flexibility of the cellulose ester film and the bleed out of the plasticizer were evaluated by changing the content of the plasticizer B added to the cellulose ester film of the hard coat film of Example 1 and the total amount of the plasticizer (plasticizer A + plasticizer B) Respectively. The results are shown in Table 3.

Here, the flexibility of the film was evaluated based on the following criteria based on the feel of the film.

0: There is sufficient breaking strength.

△: There is a breaking strength to achieve the target.

Further, the bleed-out of the plasticizer was evaluated by naked eyes based on the following criteria after exposing the cellulose ester film to the durability conditions of high temperature and high humidity.

◎: Not at all.

○: Almost none.

C: Very rarely, there is no problem in actual use.

X: Occurred frequently, and can not withstand use.

From Table 3, it can be seen that the target breaking strength can be attained by the flexibility of the film when the plasticizer B is not contained (see Examples 1-9). However, in order to sufficiently attain the breaking strength, % Or more. If the total amount of the plasticizers is 21% by weight (see Examples 1-13), bleed-out of the plasticizer rarely occurs. In order to reliably suppress the occurrence of bleed-out, the total amount of the plasticizers is preferably 20% It can be said that there is a need.

Although the hard coating film is applied to a polarizing plate of a liquid crystal display device in the above description, the hard coating film produced by the manufacturing method of this embodiment may be used as a film for protecting the surface of the touch panel, It can also be used as a glass shatterproof film.

The present invention can be used, for example, in the production of a hard coat film adhered to a polarizer polarizer film of a liquid crystal display device or a hard coat film adhered to a substrate surface of a touch panel or an image display device.

6: metal support (support)
41: cellulose ester film (thin film optical film)
41a: cotton
51: Hard coating layer
60: hard coating film

Claims (5)

1 to 20% by weight of a plasticizer having a property of being formed by the solution softening method and having a property of being localized on the support side at the time of forming in the film forming process and also having a film thickness of 15 탆 or more and 30 Wherein the hard coat layer is applied to a side of the thin film optical film having a concentration of the fine silica particles larger than an average concentration of the thin film optical film over the entirety of the thin film optical film. The method of claim 1, wherein the plasticizer is a phosphate plasticizer. The hard coating film of claim 1, wherein the thickness of the hard coating layer is 0.5 占 퐉 or more and 10 占 퐉 or less. The plasticizer according to any one of claims 1 to 3, wherein the plasticizer is a first plasticizer,
Wherein the thin film optical film contains at least 1% by weight of a second plasticizer different from the first plasticizer,
Wherein the total amount of the first plasticizer and the second plasticizer in the thin film optical film is 20 wt% or less. 5. The method of claim 4, wherein the second plasticizer is a phthalic acid or polyhydric alcohol ester plasticizer.

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