WO2015151795A1

WO2015151795A1 - Optical film, polarizing plate, method for producing polarizing plate, image display device and method for manufacturing image display device

Info

Publication number: WO2015151795A1
Application number: PCT/JP2015/057845
Authority: WO
Inventors: 知世安達
Original assignee: コニカミノルタ株式会社
Priority date: 2014-04-03
Filing date: 2015-03-17
Publication date: 2015-10-08

Abstract

This optical film (15) comprises a hard coat layer (13) on at least one surface of a film base (12). The film base (12) contains at least one compound selected from among hindered amine compounds, polymers containing a repeating unit derived from a monomer represented by general formula (P), organic acids represented by general formula (Q) and compounds represented by general formula (S). The hard coat layer (13) has a surface free energy of 30 mN/m or more after an alkali treatment.

Description

Optical film, polarizing plate, manufacturing method of polarizing plate, image display device, and manufacturing method of image display device

The present invention relates to an optical film having a hard coat layer on at least one surface of a film substrate, a polarizing plate having the optical film and a manufacturing method thereof, an image display device having the polarizing plate, and a manufacturing method thereof. It is.

It is required to impart functions such as scratch resistance, antireflection, and antistatic to the surface of a polarizing plate used in an image display device such as a liquid crystal display device (LCD). As a method for improving the scratch resistance, it is common to apply a hard coat layer that is cured by irradiation with active energy rays on a film substrate such as a cellulose ester film and arrange it as a polarizing plate protective film.

However, when the liquid crystal display device is irradiated with light for a long time when used outdoors, there is a problem that the hard coat layer is easily peeled off from the film base material, and improvement has been demanded. In view of such problems, a method for improving the adhesion between the hard coat layer and the cellulose ester film by adding a hindered amine compound to the cellulose ester film as a means for improving the light resistance (peeling resistance) of the protective film is proposed. (For example, refer to Patent Document 1).

In order to improve the polarizer durability under high temperature and high humidity and high temperature and low humidity, the cellulose ester film may contain a specific organic acid, a specific phenol compound, or a specific polymer containing a benzene ring in the main chain. It is known to add (for example, refer to Patent Document 2).

Further, in recent years, for example, on a liquid crystal display panel of a smartphone or a tablet terminal, a transparent protective part made of glass or plastic is provided from the viewpoint of improving mechanical strength and designability. In this case, if a gap layer exists between the polarizing plate protective film on the surface of the liquid crystal display panel and the protective part, light reflection or reflection at the interface between the liquid crystal display panel and the gap layer or between the protective part and the gap layer may occur. The contrast and brightness decrease due to scattering. For this reason, there has been proposed a technique for avoiding the above inconvenience by filling the gap layer with a filler such as a photocurable resin (for example, see Patent Document 3).

JP 2013-112585 A JP 2013-174851 A JP2013-11897A

However, the inventors of the present application provide a film base material with a hindered amine compound, a specific organic acid, a specific phenol compound, or a specific polymer containing a benzene ring in the main chain (hereinafter these are collectively referred to as a compound or the like). ) Is added to the hard coat layer of the polarizing plate protective film, and a specific system in which a protective part is provided via the filling layer, a compound or the like diffuses from the film substrate to the filling layer, and a radical of the compound or the like. A new problem has been discovered in which unevenness of curing of the resin occurs in the filling layer due to the trapping action, thereby causing poor adhesion between the protective portion and the filling layer, and in turn causing poor display (display unevenness).

The present invention has been made in order to solve the above-described problems, and the object thereof is to provide a non-uniform curing of the filling layer and a display thereby when a protective part is provided on the hard coat layer via the filling layer. In order to suppress the occurrence of defects, the optical film capable of suppressing the diffusion of the compound contained in the film substrate to the hard coat layer surface, the polarizing plate having the optical film, the production method thereof, and the polarizing plate are provided. An object of the present invention is to provide an image display device and a manufacturing method thereof.

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

An optical film according to one aspect of the present invention is an optical film having a hard coat layer on at least one surface of a film substrate,
The film substrate includes a hindered amine compound, a polymer containing a repeating unit derived from a monomer represented by the following general formula (P), an organic acid represented by the following general formula (Q), and the following general formula (S). Containing at least one of the compounds represented by:
The hard coat layer has a surface free energy of 30 mN / m or more after alkali treatment.

(In the general formula (P), R ¹ represents a hydrogen atom or an aliphatic group having 1 to 4 carbon atoms. R ² represents a substituent. (A) is necessary for forming a 5- or 6-membered ring. Represents an atomic group, and n represents an integer of 0 to 4.)

(In general formula (Q), R ²⁶ represents an aryl group, and R ²⁷ and R ²⁸ each independently represents a hydrogen atom, an alkyl group, or an aryl group.)

(In the general formula (S), R ¹ represents a hydrogen atom or a substituent, R ² represents a substituent represented by the following general formula (a). N1 represents an integer of 0 to 4, and n1 is 2 In the above, a plurality of R ¹ may be the same or different from each other, n2 represents an integer of 1 to 5, and when n2 is 2 or more, a plurality of R ² may be the same or different from each other May be.)

(In the general formula (a), A represents a substituted or unsubstituted aromatic ring, and R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or the following general formula (b R ⁵ represents a single bond or an alkylene group having 1 to 5 carbon atoms, X represents a substituted or unsubstituted aromatic ring, and n3 represents an integer of 0 to 10 And when n3 is 2 or more, the plurality of R ⁵ and X may be the same or different.

(In the general formula (b), X represents a substituted or unsubstituted aromatic ring, and R ⁶ , R ⁷ , R ⁸ , and R ⁹ are each independently a hydrogen atom or an alkyl having 1 to 5 carbon atoms. N5 represents an integer of 1 to 11, and when n5 is 2 or more, a plurality of R ⁶ , R ⁷ , R ⁸ and X may be the same or different.
It is.

Since the hard coat layer of the optical film is hydrophilized with a surface free energy of 30 mN / m or more, the hindered amine compound contained in the film base material diffuses to the hard coat layer side in this hydrophilized state. Even so, the compound and the like can be trapped in the hydrophilic portion of the hard coat layer. That is, diffusion of the compound or the like to the hard coat layer surface can be suppressed.

Thereby, for example, even when a protective part is provided on the hard coat layer via a filling layer, diffusion of a compound or the like to the filling layer can be suppressed, so that occurrence of curing unevenness in the filling layer can be suppressed. The adhesion failure between the protective part and the filling layer due to the unevenness of curing can be suppressed. As a result, in the image display device using the optical film, the occurrence of display defects can be suppressed.

1 is a cross-sectional view illustrating a schematic configuration of an image display device according to an embodiment of the present invention. It is a top view which shows typically the structure of the outline of the manufacturing apparatus of the diagonally stretched film used by the said embodiment. It is a top view which shows typically an example of the rail pattern of the extending | stretching part of the said manufacturing apparatus.

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

The inventors of the present application have studied various methods for improving the curing unevenness of the filled layer when an optical film (polarizing plate protective film) containing a hindered amine compound or the like is used. As a result, the hard coat layer on the polarizer protective film is hydrophilized so that the surface free energy is 30 mN / m or more, so that the compound diffused from the film substrate is trapped in the hard coat layer, and then filled into the filling layer. It was found that preventing the spread of Thereby, it is possible to provide a filling layer on the polarizing plate protective film without causing uneven curing, poor adhesion between the protective part and the filling layer, and poor appearance or display failure of the image display device due to uneven curing. Etc. could be prevented. Hereinafter, the image display apparatus of this embodiment will be described.

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

The liquid crystal display panel 2 is configured by disposing polarizing

plates

5 and 6 on both sides of a liquid crystal cell 4 (display cell) in which a liquid crystal layer is sandwiched between a pair of substrates. The polarizing plate 5 is attached to one surface side (for example, the viewing side) of the liquid crystal cell 4 via the adhesive layer 7. The polarizing plate 6 is attached to the other surface side (for example, the backlight 9 side) of the liquid crystal cell 4 through the adhesive layer 8. The driving method of the liquid crystal display panel 2 is not particularly limited, and various driving methods such as an IPS (In Plane Switching) type and a TN (Twisted Nematic) method can be employed.

The polarizing plate 5 includes a polarizer 11 that transmits predetermined linearly polarized light, a film base 12 and a hard coat layer 13 that are sequentially laminated on the protective portion 3 side of the polarizer 11, and a liquid crystal cell 4 side of the polarizer 11. It is comprised with the optical film 14 laminated | stacked. The film base 12 and the hard coat layer 13 constitute an optical film 15 as a protective film formed on the surface on the viewing side of the polarizer 11. The film substrate 12 is made of, for example, a cellulose ester film, but is not limited to this cellulose ester film. By providing the hard coat layer 13 on the film substrate 12, the surface of the polarizing plate 5 can be protected.

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

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

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

The film substrate 12 may contain a hindered amine compound. The optical film 15 in which the hard coat layer 13 is formed on the film substrate 12 is bonded (UV bonded) to the polarizer 11 by, for example, ultraviolet irradiation. By this UV irradiation, the film substrate 12 and the hard coat layer are bonded. 13 (light-resistant adhesion) may deteriorate. However, when the film base 12 contains a hindered amine compound, the above light-resistant adhesion can be improved.

In addition, in order to suppress the deterioration of the polarizer 11 under high temperature and high humidity or high temperature and low humidity, the film substrate 12 includes a specific organic acid, a specific phenol compound, or a specific polymer containing a benzene ring in the main chain. May be contained.

The details of the above hindered amine compounds and specific organic acids will be described later.

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

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

[Surface free energy]
In the present embodiment, the hard coat layer 13 of the optical film 15 is a layer having a surface free energy of 30 mN / m or more. Here, the surface free energy of the hard coat layer 13 is a polar component a (mN / m), a hydrogen bond component b (mN / m), and a dispersion component c (mN / m) of the surface free energy of the hard coat layer 13. Refers to the sum of In addition, the calculation method of these components is mentioned later.

The hard coat layer 13 is hydrophilized with a surface free energy of 30 mN / m or more. In this hydrophilized state, even if a hindered amine compound or the like contained in the film substrate 12 is diffused to the hard coat layer 13 side, the compound or the like can be trapped in the hydrophilized portion of the hard coat layer 13. it can. That is, the diffusion of the compound or the like to the hard coat layer 13 surface can be suppressed.

Thereby, even when providing the protective part 3 via the filling layer 31 on the hard coat layer 13 as in the present embodiment, the diffusion of the compound or the like in the film substrate 12 to the filling layer 31 is suppressed. Generation | occurrence | production of the nonuniformity of hardening can be suppressed in the filling layer 31, and the adhesion failure of the protection part 3 and the filling layer 31 by this hardening nonuniformity can be suppressed. As a result, in the image display device 1, it is possible to suppress appearance defects and display defects due to poor adhesion. In addition, it is desirable that the surface free energy of the hard coat layer 13 is 40 mN / m or more from the viewpoint of easily obtaining the target effect of the present embodiment.

From the viewpoint of reliably hydrophilizing the surface of the hard coat layer 13 and reliably obtaining the above effects, the hard coat layer 13 is preferably subjected to an alkali treatment under the following alkaline conditions.
[Alkali treatment conditions]
Alkaline solution: 2 mol / L sodium hydroxide solution Treatment temperature: 50 ° C
Processing time: 120 seconds

Further, the surface free energy of the hard coat layer 13 can be increased by increasing the content of fine particles, which will be described later. However, if the fine particles are contained to exceed 100 mN / m, the transparency and water resistance of the hard coat layer 13 are increased. Decreases. For this reason, the surface free energy of the hard coat layer 13 is preferably 100 mN / m or less.

Further, it is desirable that the hard coat layer 13 contains fine particles, and above all, it is desirable that the hard coat layer 13 contains fine particles coated with a polymer silane coupling agent. In this case, the surface free energy of the hard coat layer 13 can be easily realized as 30 mN / m or more.

Further, it is desirable that the concentration of the polymer silane coupling agent-coated fine particles on the surface of the hard coat layer 13 is larger than the concentration of the polymer silane coupling agent-coated fine particles in the entire hard coat layer 13. In this case, since the vicinity of the surface of the hard coat layer 13 is reliably hydrophilized, the compound or the like contained in the film base 12 is reliably trapped near the surface of the hard coat layer 13 and diffused to the filling layer 31 side. Can be reliably suppressed. The concentration of the polymer silane coupling agent-coated fine particles on the surface of the hard coat layer 13 may be a concentration at a portion of the hard coat layer 13 that is 10% or less of the entire thickness of the hard coat layer 13. .

Next, a method for calculating the polar component a, the hydrogen bond component b, and the dispersion component c of the surface free energy will be described. First, the optical film 15 is allowed to stand for 12 hours under conditions of a temperature of 23 ° C. and a humidity of 55%, and then contact angles of three types of droplets (pure water, ethylene glycol, diethylene glycol) with respect to the surface of the hard coat layer 13 of the optical film 15. (Θ) is measured under the conditions of a temperature of 23 ° C. and a humidity of 55% using a product name Drop Master DM100 manufactured by Kyowa Interface Science Co., Ltd. In addition, the measurement of the contact angle of each droplet is performed 5 times, and the average value thereof is used.

Next, the surface free energy is obtained using the following Young-Fowkes equation.
(Γ _S d · γ _L d) ^1/2 + (γ _S p · γ _L p) ^1/2 + (γ _S h · γ _L h) ^1/2
= Γ _L (1 + cos θ) / 2
here,
γ _S d: Dispersion component of solid surface free energy (mN / m)
γ _L d: Dispersion component of liquid surface free energy (mN / m)
γ _S p: Polar component of surface free energy of solid (mN / m)
γ _L p: Polar component of liquid surface free energy (mN / m)
γ _S h: hydrogen bonding component of solid surface free energy (mN / m)
γ _L h: hydrogen bond component of surface free energy of solid (mN / m)
γ _L : Sum of dispersion component, polar component and hydrogen bond component of surface free energy of liquid (γ _L = γ _L d + γ _L p + γ _L h)
θ: Contact angle (°)

The dispersion component γ _L d, the polar component γ _L p, and the hydrogen bond component γ _L h of the surface free energy of the three types of droplets (pure water, ethylene glycol, and polyethylene glycol) are described in Japan Adhesion Association Vol. 15, no. 3, the numerical value described in p96 is used.

By substituting the value of the contact angle (average contact angle) into the above Young-Fowkes equation and solving the ternary simultaneous equations, the dispersion component γ _S d (= c) of the surface free energy of the solid, the polar component γ _S Each value of p (= a) and hydrogen bond component γ _S h (= b) can be obtained.

[Contact angle]
In order to satisfactorily exhibit the effects of the present embodiment described above, the difference Δθ in the contact angle of water before and after the alkali treatment in the hard coat layer 13 is desirably 10 ° or more, and more preferably 20 ° or more. desirable. The contact angle difference Δθ is desirably 55 ° or less. Hereinafter, the difference Δθ in the contact angle before and after the alkali treatment will be described.

The difference Δθ (°) in the water contact angle before and after the alkali treatment is alkali-treated under the following conditions at least from the water contact angle θa (°) before the alkali treatment of the hard coat layer 13 of the optical film 15. This is a value obtained by subtracting the water contact angle θb (°) of the hard coat layer 13 after the heat treatment. The alkali treatment conditions are conditions in which the optical film 15 is immersed in a 2 mol / L sodium hydroxide solution at 50 ° C. for 60 seconds. The water contact angle is a value obtained by averaging the measured values after performing the measurement for 5 times using the contact angle meter described above after standing for 12 hours under the conditions of 23 ° C. and 55% RH.

The surface free energy of the hard coat layer 13 is increased after the alkali treatment, the adhesion at the interface between the filling layer 31 (photocurable resin) and the hard coat layer 13 is increased, and the interlayer adhesion after the durability test is excellent. It is done. Moreover, it is a preferable aspect in this embodiment that a water contact angle falls after alkali treatment.

The alkali treatment in the present embodiment includes a step of rinsing at least the optical film 15 in an alkali solution (hereinafter also referred to as a saponification step) and then washing and drying, and the conditions for the alkali treatment are the above-described conditions. Further, after the alkali treatment, neutralization in an acidic water step may be performed, followed by washing with water and drying.

By adjusting the type and amount of additives such as compounds to be described later and the curing conditions (oxygen concentration adjustment, etc.) when forming the hard coat layer, the difference Δθ in the contact angle of water before and after the alkali treatment satisfies the above range. Can be adjusted as follows.

Further, in order to make the surface free energy of the hard coat layer of the optical film 30 mN / m or more, the hard coat layer may be surface-modified. Examples of the surface modification method include plasma irradiation treatment, corona irradiation treatment, solvent treatment and the like. These surface modification methods may be performed singly or in combination.
[Optical film]
Hereinafter, the detail of each layer which comprises the optical film 15 mentioned above is demonstrated.

(Hard coat layer)
The hard coat layer of the present embodiment is a layer composed mainly of a resin. Specifically, it is preferable to contain an actinic radiation curable resin from the viewpoint of excellent mechanical film strength (abrasion resistance, pencil hardness). That is, it is a layer mainly composed of a resin that is cured through a crosslinking reaction by irradiation with active rays (also called active energy rays) such as ultraviolet rays and electron beams. As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and an actinic radiation curable resin layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams. The

Typical examples of the actinic radiation curable resin include an ultraviolet curable resin and an electron beam curable resin, but a resin curable by ultraviolet irradiation is particularly excellent in mechanical film strength (abrasion resistance, pencil hardness). It is preferable from the point. Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable resin. A curable epoxy resin or the like is preferably used, and an ultraviolet curable acrylate resin is particularly preferable.

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

Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, glycerol triacrylate relay , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol di Methacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pen Preferred examples include erythritol tetramethacrylate, glycerin trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, active energy ray-curable isocyanurate derivatives, and polybasic acidic acrylates. It is done.

From the viewpoint of the objective effect of the present embodiment, the hard coat layer of the optical film may contain a polybasic acidic acrylate. Examples of polybasic acidic acrylates include dipentaerythritol pentaacrylate succinic acid modification, pentaerythritol triacrylate succinic acid modification, dipentaerythritol pentaacrylate phthalic acid modification, pentaerythritol triacrylate phthalic acid modification, polybasic acid modified acrylic An oligomer etc. can be mentioned. Examples of commercially available products include Aronix M-510, Aronix M-520 (manufactured by Toagosei Co., Ltd.), DPE6A-MS, PE3A-MP, DPE6A-MP, PE3A-MP (manufactured by Kyoeisha Chemical Co., Ltd.) and the like. The content is preferably 30% or more by mass ratio, more preferably 50% or more by mass ratio, assuming that the resin component forming the hard coat layer film is 100.

Other commercially available resins include Adekaoptomer N series, Sun Rad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (Sanyo Chemical Industries ( Alonix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (manufactured by Toagosei Co., Ltd.), NK-Ester A -TMM-3L, NK-ester AD-TMP, NK-ester ATM-35E, NK ester A-DOG, NK ester A-IBD-2E, A-9300, A-9300-1CL (Shin Nakamura Chemical Co., Ltd.) ), PE-3A (Kyoeisha Chemical) and the like.

The actinic radiation curable resins may be used alone or in combination of two or more.

In addition, a monofunctional acrylate may be used. Monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl Examples thereof include acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Such monofunctional acrylates can be obtained from Nippon Kasei Kogyo Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., etc.

When using a monofunctional acrylate, it is preferable that the mass ratio of the polyfunctional acrylate and the monofunctional acrylate is polyfunctional acrylate: monofunctional acrylate = 80: 20 to 98: 2.

(Photopolymerization initiator)
The hard coat layer preferably contains a photopolymerization initiator to accelerate the curing of the actinic radiation curable resin.

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

(Fine particles)
It is preferable that the hard coat layer contains fine particles because the surface free energy of the hard coat layer after the alkali treatment can be increased. Although it will not restrict | limit especially if it is used for a hard-coat layer as a microparticle, A silica, an alumina, a zirconia, a titanium oxide, an antimony pentoxide etc. are mentioned, Preferably it is a silica. The silica fine particles may be hollow particles having cavities inside. It is preferable that the hard coat layer contains fine particles formed by coating with a polymer silane coupling agent, which can exhibit good performance particularly with respect to adhesion after a durability test. The content is preferably such that the fine particle: active ray curable resin = 0.1: 100 to 400: 100, in order to increase the surface free energy.

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

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

It is also possible to use a polymer (oligomer or prepolymer) of these polymerizable monomers. These polymerizable monomers may be used alone or in combination. (Meth) acryl means acryl or methacryl, and (meth) acrylate means acrylate or methacrylate.

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

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

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

Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene and xylene, esters such as ethyl acetate and ethylene glycol monomethyl ether, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and ethers such as tetrahydrofuran and dioxane. , Alcohols such as methanol and isopropanol, and halogenated hydrocarbons such as chloroform. These can also be mixed and used. At this time, the total concentration of the polymerizable monomer and the reactive silane compound is preferably in the range of 1 to 40% by weight, more preferably 2 to 30% by weight as the solid content.

Polymerization initiators include azoisobutyl nitrile, lauroyl peroxide, benzoyl peroxide, di-t-butyl peroxide, t-butylperoxy-2-ethylhexinoate, t-butylperoxyisobutyrate, t- Peroxide polymerization initiators such as butyl peroxypivalate, t-butyl peroxybenzoate, t-butyl peroxyacetate, 2,2-azobisisobutyronitrile, 2,2-azobis (2,4-dimethyl) And azo compounds such as 2,2-azobis (4-methoxy-2,4-dimethylvaleronitrile).

The reaction temperature is preferably in the range of 30 to 100 ° C, more preferably 50 to 95 ° C. If the reaction temperature is low, the reaction is slow and it may take too long to prepare a polymeric silane coupling agent with a large molecular weight. On the other hand, if the reaction temperature is too high, the reaction rate may be too high and the desired molecular weight may not be controlled. The molecular weight of the polymer silane coupling agent is preferably in the range of 2,500 to 150,000, more preferably 2,000 to 100,000 in terms of polystyrene.

The thickness of the coating layer of the polymer silane coupling agent is preferably 1 to 10 nm, more preferably 1 to 5 nm. If the coating layer is thin, dispersibility of the fine particles in the matrix component may be insufficient. Moreover, when the coating layer is too thick, there is a problem that productivity is lowered.

Further, the content of the coating layer in the polymer silane coupling agent-coated fine particles is preferably in the range of 0.5 to 20% by weight, more preferably 1 to 15% by weight as the solid content.

(Method for preparing polymer silane coupling agent coated fine particles)
Specifically, the polymer silane coupling agent-coated fine particles can be prepared by adding a polymer silane coupling agent to a fine particle organic solvent dispersion and coating the fine particles with the polymer silane coupling agent in the presence of an alkali.

Organic solvents include methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, isopropyl glycol and other alcohols; acetic acid methyl ester , Esters such as ethyl acetate, butyl acetate; ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether; acetone , Methyl ethyl ketone, methyl isobutyl ketone, acetylacetone Ketones such as acetoacetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, toluene, cyclohexanone, isophorone and the like.

The total concentration of the fine particles and the polymer silane coupling agent in the dispersion is preferably 1 to 30% by weight, more preferably 2 to 25% by weight as the solid content.

¡Alkali is added to the dispersion to adsorb the polymer silane coupling agent to the fine particles. By adding an alkali, the surface of the fine particles is activated (generation of OH groups), and the affinity between the polymer silane coupling agent and the fine particles is increased and bonded. Alternatively, it is conceivable that the dehydration reaction between the OH group of the polymer silane coupling agent and the OH group of the fine particles is promoted to promote bonding.

In addition to sodium hydroxide, potassium hydroxide and the like, basic nitrogen compounds such as ammonia and amines are used as the alkali. Among these, a basic nitrogen compound is preferable in that the adsorption and bonding of the polymer silane coupling agent to the fine particles are promoted and the amount of the unadsorbed polymer silane coupling agent is small.

The amount of alkali used varies depending on the type of metal oxide particles, the average particle size, etc., but is in the range of 0.001 to 0.2 parts by weight, more preferably 0.005 to 0.1 parts by weight of the fine particles. Is preferred.

Next, the polymer silane coupling agent-coated fine particles can be obtained by separating and drying the fine particles adsorbed with the polymer silane coupling agent.

The average particle size of the obtained polymer silane coupling agent-coated fine particles is preferably 5 to 500 nm, more preferably 10 to 200 nm, from the viewpoint of securing optical properties when used for an optical film.

From the viewpoint of securing the film strength of the hard coat layer, the content of the polymer silane coupling agent-coated fine particles in the hard coat layer is 0.5 to 80 parts by mass, more preferably 1 to 60 parts by mass as a solid content. To preferred.

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

(Additive)
The hard coat layer may contain a fluorine-siloxane graft compound, a fluorine compound, a silicone compound, or a compound having an HLB value of 3 to 18 from the viewpoint of improving the coatability. The hydrophilicity can be easily controlled by adjusting the types and amounts of these additives.

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

HLB = 7 + 11.7Log (Mw / Mo)
In the formula, Mw represents the molecular weight of the hydrophilic group, Mo represents the molecular weight of the lipophilic group, and Mw + Mo = M (molecular weight of the compound). Alternatively, according to the Griffin method, HLB value = 20 × total formula weight of hydrophilic part / molecular weight (J. Soc. Cosmetic Chem., 5 (1954), 294) and the like.

Specific compounds of compounds having an HLB value of 3 to 18 are listed below, but are not limited thereto. Figures in parentheses indicate HLB values.

Made by Kao Corporation: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), Emulgen 105 (9.7), Emulgen 106 (10.5), Emulgen 108 (12. 1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2) , Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0), Emulgen 409PV (12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5), Emulgen 707 (12.1), Emulgen 09 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4), Emulgen 1135S-70 (17.9), Emulgen 2020G-HA (13.0), Emulgen 2025G (15. 7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), manufactured by Nissin Chemical Industry Co., Ltd .: Surfynol 104E (4), Surfynol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4), Surfinol 104S (4), Surfi Knoll 420 (4), Surfynol 440 (8), Surfynol 4 5 (13), Surfynol 485 (17), Surfynol SE (6), Shin-Etsu Chemical Co., Ltd.: X-22-4272 (7), X-22-6266 (8).

The fluorine-siloxane graft compound refers to a copolymer compound obtained by grafting polysiloxane and / or organopolysiloxane containing siloxane and / or organosiloxane alone on at least a fluorine resin. Such a fluorine-siloxane graft compound can be prepared by a method as described in Examples described later. Alternatively, examples of commercially available products include ZX-022H, ZX-007C, ZX-049, and ZX-047-D manufactured by Fuji Chemical Industry Co., Ltd.

Further, examples of the fluorine-based compound include Megafac series (F-477, F-487, F-569, etc.) manufactured by DIC Corporation, OPTOOL DSX, OPTOOL DAC, etc. manufactured by Daikin Industries, Ltd.

Examples of silicone compounds are Shin-Etsu Chemical Co., Ltd .: KF-351, KF-352, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-618, KF-6011, KF. -6015, KF-6004, manufactured by BYK Japan, Inc .: BYK-UV3576, BYK-UV3535, BYK-UV3510, BYK-UV3505, BYK-UV3500, and the like. These components are preferably added in the range of 0.005 parts by mass or more and 10 parts by mass or less with respect to the solid component in the hard coat layer composition. Two or more kinds of these components may be added as long as the total additive amount is in the range of 0.005 parts by mass or more and 10 parts by mass or less.

(UV absorber)
A hard-coat layer may further contain the ultraviolet absorber demonstrated by the cellulose-ester film mentioned later. When the film is composed of two or more layers, it is preferable that the hard coat layer in contact with the film substrate contains the ultraviolet absorber.

The content of the UV absorber is preferably such that the UV absorber: hard coat layer constituting resin = 0.01: 100 to 20: 100 in terms of mass ratio. When two or more layers are provided, the film thickness of the hard coat layer in contact with the film substrate is preferably in the range of 0.05 to 2 μm. Two or more layers may be formed as a simultaneous multilayer. The simultaneous multi-layering is to form a hard coat layer by applying two or more hard coat layers on a base material without going through a drying step. In order to laminate the second hard coat layer on the first hard coat layer without using a drying step, the layers are stacked one after another by an extrusion coater or with a slot die having a plurality of slits. Simultaneous layering may be performed.

(solvent)
The hard coat layer is formed by diluting the above-described components forming the hard coat layer with a solvent that swells or partially dissolves the film base material, and is applied onto the film base material as follows. It is preferable to provide by drying and curing.

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

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

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

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

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

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

Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually in the range of 50 to 1000 mJ / cm ² , preferably in the range of 50 to 300 mJ / cm ² . In the UV curing treatment, oxygen removal (for example, replacement with an inert gas such as nitrogen purge) can be performed to prevent reaction inhibition by oxygen. The cured state of the surface can be controlled by adjusting the removal amount of the oxygen concentration. This makes it possible to control the presence state of the additive on the hard coat layer surface, and as a result, it is easy to control the contact angle difference Δθ within the above-described range.

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

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

(Back coat layer)
It is preferable to provide a backcoat layer on the surface opposite to the side on which the hard coat layer of the optical film (for example, hard coat film) of the present embodiment is provided. The back coat layer is provided to correct curl caused by providing a hard coat layer or other layers by coating or CVD. That is, the degree of curling can be balanced by imparting the property of being rounded with the surface on which the backcoat layer is provided facing inward. In addition, it is also preferable that the back coat layer is preferably applied as an anti-blocking layer. In that case, it is preferable that fine particles are added to the back coat layer coating composition in order to provide an anti-blocking function. . This back coat layer may satisfy the above-described conditional expressions (1) and (2).

As fine particles added to the backcoat layer, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, and oxide. Mention may be made of indium, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low haze, and silicon dioxide is particularly preferable.

These fine particles are commercially available under the trade names of, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Nippon Aerosil Co., Ltd.). . Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used. Examples of the polymer fine particles include a silicone resin, a fluororesin, and an acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

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

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

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

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

These coating compositions are preferably applied on the surface of the transparent resin film with a gravure coater, dip coater, reverse coater, wire bar coater, die coater, etc., with a wet film thickness of 1 to 100 μm, particularly 5 to 30 μm. Preferably there is. The back coat layer may contain a resin as a binder. Examples of the resin used as the binder for the backcoat layer include vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, vinyl acetate resin, vinyl acetate-vinyl alcohol copolymer, partially hydrolyzed vinyl chloride-vinyl acetate copolymer. Polymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, ethylene-vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, etc. Vinyl polymer or copolymer, nitrocellulose, cellulose acetate propionate (preferably acetyl group substitution degree 1.8-2.3, propionyl group substitution degree 0.1-1.0), diacetylcellulose, cellulose Cellulose derivatives such as acetate butyrate resin, maleic acid and / or Or acrylic acid copolymer, acrylic ester copolymer, acrylonitrile-styrene copolymer, chlorinated polyethylene, acrylonitrile-chlorinated polyethylene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylic resin Rubber resins such as polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amino resin, styrene-butadiene resin, butadiene-acrylonitrile resin, Examples thereof include, but are not limited to, silicone resins and fluorine resins. For example, as acrylic resins, Acrypet MD, VH, MF, V (manufactured by Mitsubishi Rayon Co., Ltd.), Hyperl M4003, M-4005, M-4006, M-4202, M-5000, M-5001, M-4501 (manufactured by Negami Kogyo Co., Ltd.), Dialnal BR-50, BR-52, BR-53, BR-60, BR-64, BR-73, BR-75, BR-77, BR-79, BR -80, BR-82, BR-83, BR-85, BR-87, BR-88, BR-90, BR-93, BR-95, BR-100, BR-101, BR-102, BR-105 BR-106, BR-107, BR-108, BR-112, BR-113, BR-115, BR-116, BR-117, BR-118, etc. (Mitsubishi Rayon Co., Ltd.) acrylic and The methacrylic monomers such as various homopolymers and copolymers were prepared as raw materials are commercially available and can also be selected preferred mono from this appropriate.

Particularly preferred are cellulose resin layers such as diacetyl cellulose and cellulose acetate propionate.

The order of coating the backcoat layer may be before or after coating the optical film on the side opposite to the backcoat layer (hard coat layer or other layer such as an antistatic layer). When the back coat layer also serves as an anti-blocking layer, it is desirable to coat it first. Alternatively, the back coat layer can be applied in two or more times before and after the coating of the hard coat layer.

[Optical film characteristics]
(Surface shape)
The arithmetic average roughness Ra (JIS B0601: 2001) of the hard coat layer is preferably in the range of 2 to 100 nm, particularly preferably in the range of 2 to 20 nm. By setting the arithmetic average roughness Ra within the above range, the visibility and the clearness are excellent. The arithmetic average roughness Ra is a value measured with an optical interference surface roughness meter (manufactured by ZYGO, NewView) according to JIS B0601: 2001.

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

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

[Film base]
It is preferable that the film substrate is easy to produce, has good adhesion to the hard coat layer, isotropic optically, and transparent.

The material for the film substrate is not particularly limited as long as it has the above-mentioned properties. For example, cellulose esters such as cellulose diacetate film, cellulose triacetate film, cellulose acetate propionate film, cellulose acetate butyrate film, etc. Film, polyester film, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyester film such as polyethylene terephthalate and polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film , Polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film Cycloolefin polymer film (Arton (manufactured by JSR), ZEONEX, ZEONOR (manufactured by Nippon Zeon)), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film , Polymethylmethacrylate film, acrylic film, polylactic acid film, glass plate, and the like. Among these, a cellulose ester film, a polycarbonate film, and a cycloolefin polymer film are preferable, and a cellulose ester film is particularly preferable.

Examples of the cellulose ester film (hereinafter also referred to as cellulose acetate film) include a triacetyl cellulose film, a cellulose acetate propionate film, a cellulose diacetate film, and a cellulose acetate butyrate film. The cellulose ester film may be used in combination with polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate resins, polyethylene resins, polypropylene resins, norbornene resins, fluororesins, and cycloolefin polymers. Examples of the commercially available cellulose ester film include Konica Minoltak KC8UX, KC4UX, KC8UY, KC4UY, KC6UA, KC4UA, KC2UA, KC4UE and KC4UZ (manufactured by Konica Minolta, Inc.). The refractive index of the cellulose ester film is preferably 1.45 to 1.55. The refractive index can be measured according to JIS K7142-2008.

(Cellulose ester resin)
The cellulose ester resin (hereinafter also referred to as cellulose ester or cellulose resin) contained in the cellulose ester film is preferably a lower fatty acid ester of cellulose. Lower fatty acid means a fatty acid having 6 or less carbon atoms. Examples of the lower fatty acid ester of cellulose include, for example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate and the like, and mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate. it can.

Particularly preferably used lower fatty acid esters of cellulose are cellulose diacetate, cellulose triacetate, and cellulose acetate propionate. These cellulose esters can be used alone or in combination.

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

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

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

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

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

The method for measuring the degree of substitution of the acyl group can be measured according to ASTM-D817-96.

The number average molecular weight (Mn) and molecular weight distribution (Mw) of the cellulose ester can be measured using high performance liquid chromatography. The measurement conditions are as follows.
Solvent: Methylene chloride Column: Shodex K806, K805, K803G
(Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw = 1000,000 to 500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.

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

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

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

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

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

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

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

Ro can be calculated by measuring the birefringence at each wavelength in an environment of 23 ° C. and 55% RH using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments).

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

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

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

(Retardation adjuster)
The retardation adjustment of λ / 4 can be performed by adding the following retardation adjuster to the resin film described above.

As the retardation adjusting agent, an aromatic compound having two or more aromatic rings as described in the specification of European Patent 911,656A2 can be used.

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

(Polycarbonate resin)
A polycarbonate resin can also be used for the film substrate. Various polycarbonate resins can be used without particular limitation, and aromatic polycarbonate resins are preferred from the viewpoint of chemical properties and physical properties, and bisphenol A polycarbonate resins are particularly preferred. Among these, those using a bisphenol A derivative in which a benzene ring, a cyclohexane ring, an aliphatic hydrocarbon group and the like are introduced into bisphenol A are more preferable. Furthermore, a polycarbonate resin having a structure in which the anisotropy in the unit molecule is reduced, obtained by using a derivative in which the functional group is introduced asymmetrically with respect to the central carbon of bisphenol A, is particularly preferable. As such a polycarbonate resin, for example, two methyl groups in the center carbon of bisphenol A are replaced by benzene rings, and one hydrogen of each benzene ring of bisphenol A is centered by a methyl group or a phenyl group. A polycarbonate resin obtained by using an asymmetrically substituted carbon is particularly preferable.

Specifically, 4,4′-dihydroxydiphenylalkane or a halogen-substituted product thereof can be obtained by a phosgene method or a transesterification method. For example, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl Examples include ethane and 4,4'-dihydroxydiphenylbutane. In addition, for example, JP 2006-215465 A, JP 2006-91836 A, JP 2005-121813 A, JP 2003-167121 A, JP 2009-126128 A, JP Examples thereof include polycarbonate resins described in 2012-31369, JP 2012-67300 A, International Publication No. 00/26705, and the like.

The polycarbonate resin may be used by mixing with a transparent resin such as polystyrene resin, methyl methacrylate resin, and cellulose acetate resin. Moreover, you may laminate | stack the resin layer containing a polycarbonate-type resin on the at least one surface of the resin film formed using the cellulose acetate type resin.

The polycarbonate-based resin preferably has a glass transition point (Tg) of 110 ° C. or higher and a water absorption (a value measured under conditions of 23 ° C. water and 24 hours) of 0.3% or less. Moreover, Tg is 120 degreeC or more, and a water absorption rate is 0.2% or less more preferable.

The polycarbonate resin film can be formed by a known method, and among them, the solution casting method and the melt casting method are preferable.

(Alicyclic olefin polymer resin)
As the film substrate, an alicyclic olefin polymer resin can also be used. Examples of the alicyclic olefin polymer-based resin include cyclic olefin random multi-component copolymers described in JP-A No. 05-310845, hydrogenated polymers described in JP-A No. 05-97978, and JP-A No. 11 The thermoplastic dicyclopentadiene ring-opening polymer and hydrogenated product thereof described in JP-A-124429 can be employed.

The alicyclic olefin polymer resin is a polymer having an alicyclic structure such as a saturated alicyclic hydrocarbon (cycloalkane) structure or an unsaturated alicyclic hydrocarbon (cycloalkene) structure. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but when it is usually in the range of 4 to 30, preferably 5 to 20, more preferably 5 to 15, the mechanical strength, The properties of heat resistance and formability of the long film are highly balanced and suitable.

The proportion of the repeating unit containing the alicyclic structure in the alicyclic olefin polymer may be appropriately selected, but is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight. That's it. When the ratio of the repeating unit having an alicyclic structure in the alicyclic polyolefin resin is within this range, the transparency and heat resistance of an optical material such as a retardation film obtained from the long obliquely stretched film of the present embodiment are improved. Since it improves, it is preferable.

Examples of the olefin polymer resin having an alicyclic structure include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof. Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. And an addition copolymer of a monomer having a norbornene structure and an addition copolymer of another monomer or a hydride thereof. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability and lightness. Can be used.

As a method for forming a long film using the norbornene-based resin as described above, a solution casting method or a melt extrusion method is preferred. Examples of the melt extrusion method include an inflation method using a die, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.

As an extrusion molding method using a T die, as described in JP-A-2004-233604, a method of maintaining a molten thermoplastic resin in a stable state when closely contacting a cooling drum, retardation, A long film with small variations in optical properties such as the orientation angle can be produced.

Specifically, 1) When producing a long film by the melt extrusion method, a sheet-like thermoplastic resin extruded from a die is brought into close contact with a cooling drum under a pressure of 50 kPa or less; 2) melting When producing a long film by extrusion, the enclosure member covers from the die opening to the first cooling drum that is in close contact, and the distance from the enclosure member to the die opening or the first contact cooling drum is 100 mm or less. Method: 3) Method of heating the temperature of the atmosphere within 10 mm to a specific temperature from the sheet-like thermoplastic resin extruded from the die opening when producing a long film by the melt extrusion method; A sheet-like thermoplastic resin extruded from a die so as to satisfy the above condition is taken into close contact with a cooling drum under a pressure of 50 kPa or less; A method in which a wind having a speed difference of 0.2 m / s or less from the cooling speed of the cooling drum that is first brought into close contact with the sheet-like thermoplastic resin extruded from the die opening is produced. It is done.

This long film may be a single layer or a laminated film of two or more layers. The laminated film can be obtained by a known method such as a coextrusion molding method, a co-casting molding method, a film lamination method, or a coating method. Of these, the coextrusion molding method and the co-casting molding method are preferable.

(Fine particles)
In order to improve the handleability, the film substrate of the present embodiment has, for example, acrylic particles, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, and hydrated calcium silicate. It is preferable to contain a matting agent such as inorganic fine particles such as aluminum silicate, magnesium silicate and calcium phosphate and a crosslinked polymer. The acrylic particles are not particularly limited, but are preferably multi-layered acrylic granular composites. Among these, silicon dioxide is preferable in that the haze of the film substrate can be reduced. The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably in the range of 5 to 16 nm, and particularly preferably in the range of 5 to 12 nm.

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

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

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

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

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

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

The sugar ester compound is preferably a compound represented by the general formula (Y). Below, the compound shown by general formula (Y) is demonstrated.

(Wherein, R ₁ ~ R ₈ is 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, R ₁ R ₈ may be the same or different.

The compounds represented by formula (Y) are shown below in more detail (compound Y-1 to compound Y-23), but are not limited thereto. In the table below, when the average substitution degree is less than 8.0, any one of R ₁ to R ₈ represents a hydrogen atom.

The substitution degree distribution can be adjusted to the desired substitution degree by adjusting the esterification reaction time or mixing compounds with different substitution degrees.

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

(Plasticizer)
The film base material of this embodiment may contain a plasticizer as needed. The plasticizer is not particularly limited, but is a polyvalent carboxylic ester plasticizer, glycolate plasticizer, phthalate ester plasticizer, phosphate ester plasticizer, and polyhydric alcohol ester plasticizer, acrylic. A plasticizer etc. are mentioned. In these, an acrylic plasticizer is preferable from the viewpoint of easily controlling the cellulose ester film to the retardation value described later.

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

The glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used. Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl 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 glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.

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

Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.

The polycarboxylic acid ester plasticizer is a compound composed of an ester of a divalent or higher, preferably a divalent to 20-valent polyvalent carboxylic acid and an alcohol. Specific examples include triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate, dibutyl tartrate, tartaric acid Examples include, but are not limited to, diacetyldibutyl, tributyl trimellitic acid, tetrabutyl pyromellitic acid, and the like.

The acrylic plasticizer is preferably an acrylic polymer, and the acrylic polymer is preferably a homopolymer or copolymer of acrylic acid or alkyl methacrylate. Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate ( n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid (ε-caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl), acrylic Acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), acrylic acid (2-methoxyethyl), acrylic acid 2-ethoxyethyl), etc., or the acrylic acid ester may include those obtained by changing the methacrylic acid ester. The acrylic polymer is a homopolymer or copolymer of the above monomer, but preferably has 30% by mass or more of acrylic acid methyl ester monomer units, and has 40% by mass or more of methacrylic acid methyl ester monomer units. It is preferable. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.

When the above-mentioned plasticizer is contained in the film base material of this embodiment, it is preferably contained in an amount of 1 to 50% by mass, more preferably 5 to 35% by mass with respect to cellulose acetate. It is particularly preferable to contain 25% by mass.

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

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

Preferably used ultraviolet absorbers are benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers, and particularly preferably benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers.

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

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

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

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

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

(Hindered amine compounds)
The film base material of this embodiment may contain a hindered amine compound. The hindered amine compound functions as an antioxidant and has a structure having a bulky organic group (for example, a bulky branched alkyl group) in the vicinity of the N atom. This is a known compound and is described, for example, in columns 5-11 of US Pat. No. 4,619,956 and columns 3-5 of US Pat. No. 4,839,405. As such, 2,2,6,6-tetraalkylpiperidine compounds, or acid addition salts thereof or complexes of them with metal compounds are included. Such compounds include those of the following general formula (H).

In the above formula, R1 and R2 are a hydrogen atom or a substituent.

The substituent represented by R1 is not particularly limited, but a substituent bonded to the piperidine ring by a nitrogen atom or an oxygen atom is preferable, and an amino group, hydroxyl group, alkoxy group, aryloxy group which may have a substituent An acyloxy group is more preferable, and an amino group, a hydroxyl group, an alkoxy group, or an acyloxy group having an alkyl group, an aryl group, or a heterocyclic group as a substituent is more preferable.

The substituent represented by R2 is not particularly limited, but an alkyl group (preferably having 1 to 20, more preferably 1 to 12, particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, Isopropyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl, cyclohexyl group, etc.), alkenyl group (preferably having 2 to 20 carbon atoms, More preferably, it is 2 to 12, particularly preferably 2 to 8, and examples thereof include vinyl group, allyl group, 2-butenyl group, 3-pentenyl group, etc.), alkynyl group (preferably having 2 to 20 carbon atoms) More preferably 2 to 12, particularly preferably 2 to 8, and examples thereof include a propargyl group and a 3-pentynyl group), an aryl group The number of carbon atoms is preferably 6 to 30, more preferably 6 to 20, and particularly preferably 6 to 12, and examples thereof include a phenyl group, a biphenyl group, a naphthyl group, and the like, and an amino group (preferably a carbon atom number of 0). To 20, more preferably 0 to 10, particularly preferably 0 to 6, and examples thereof include an amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group, and the like, and an alkoxy group (preferably The number of carbon atoms is 1 to 20, more preferably 1 to 12, and particularly preferably 1 to 8, and examples thereof include a methoxy group, an ethoxy group, a butoxy group, and a cyclohexyloxy group.

Specific examples of hindered amines include 4-hydroxy-2,2,6,6-tetramethylpiperidine, 1-allyl-4-hydroxy-2,2,6,6-tetramethylpiperidine, 1-benzyl-4-hydroxy -2,2,6,6-tetramethylpiperidine, 1- (4-tert-butyl-2-butenyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2, 2,6,6-tetramethylpiperidine, 1-ethyl-4-salicyloyloxy-2,2,6,6-tetramethylpiperidine, 4-methacryloyloxy-1,2,2,6,6-pentamethyl Piperidine, 1,2,2,6,6-pentamethylpiperidin-4-yl-β (3,5-di-t-butyl-4-hydroxyphenyl) -propionate, 1-benzyl 2,2,6,6-tetramethyl-4-piperidinyl maleate, (di-2,2,6,6-tetramethylpiperidin-4-yl) -adipate, (di-2,2 , 6,6-tetramethylpiperidin-4-yl) -sebacate, (di-1,2,3,6-tetramethyl-2,6-diethyl-piperidin-4-yl) -sebacate, (di-1- Allyl-2,2,6,6-tetramethyl-piperidin-4-yl) -phthalate, 1-acetyl-2,2,6,6-tetramethylpiperidin-4-yl-acetate, trimellitic acid-tri- ( 2,2,6,6-tetramethylpiperidin-4-yl) ester, 1-acryloyl-4-benzyloxy-2,2,6,6-tetramethylpiperidine, dibutyl-malonic acid-di- (1,2 , 2,6,6-pentamethyl-piperidin-4-yl) -ester, dibenzyl-malonic acid-di- (1,2,3,6-tetramethyl-2,6-diethyl-piperidin-4-yl) -ester Dimethyl-bis- (2,2,6,6-tetramethylpiperidin-4-oxy) -silane, tris- (1-propyl-2,2,6,6-tetramethylpiperidin-4-yl) -phos Fit, tris- (1-propyl-2,2,6,6-tetramethylpiperidin-4-yl) -phosphate, N, N'-bis- (2,2,6,6-tetramethylpiperidine-4- Yl) -hexamethylene-1,6-diamine, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2, 6, -Pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, N, N'-bis- (2,2,6,6-tetramethylpiperidin-4-yl) -hexamethylene-1, 6-diacetamide, 1-acetyl-4- (N-cyclohexylacetamide) -2,2,6,6-tetramethyl-piperidine, 4-benzylamino-2,2,6,6-tetramethylpiperidine, N, N'-bis- (2,2,6,6-tetramethylpiperidin-4-yl) -N, N'-dibutyl-adipamide, N, N'-bis- (2,2,6,6-tetramethyl Piperidin-4-yl) -N, N'-dicyclohexyl- (2-hydroxypropylene), N, N'-bis- (2,2,6,6-tetramethylpiperidin-4-yl) -p-xylylene- Zia 4- (bis-2-hydroxyethyl) -amino-1,2,2,6,6-pentamethylpiperidine, 4-methacrylamide-1,2,2,6,6-pentamethylpiperidine, α- And cyano-β-methyl-β- [N- (2,2,6,6-tetramethylpiperidin-4-yl)]-amino-acrylic acid methyl ester.

Further, N, N ′, N ″, N ′ ″-tetrakis- [4,6-bis- [butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino]- Triazin-2-yl] -4,7-diazadecane-1,10-diamine, dibutylamine and 1,3,5-triazine N, N'-bis (2,2,6,6-tetramethyl-4- Piperidyl) -1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine polycondensate (BASF's CHIMASSORB-2020FDL), dibutylamine and 1,3,3 Polycondensate of 5-triazine and N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1,1,3,3-tetramethylbutyl) amino -1,3 , 5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino }] (CHIMASSORB 944FDL manufactured by BASF), 1,6-hexanediamine-N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) and morpholine-2,4,6-trichloro Polycondensate with 1,3,5-triazine, poly [(6-morpholino-s-triazine-2,4-diyl) [(2,2,6,6, -tetramethyl-4-piperidyl) imino ] -Hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]] and other high molecular weight HALS (hindered inderamine light) in which a plurality of piperidine rings are bonded via a triazine skeleton. stabilizer); a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 1,2,3,4-butanetetracarboxylic acid and 1,2,2, Mixed esterified product of 6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane Examples include, but are not limited to, high molecular weight HALS in which a piperidine ring is bonded via an ester bond. Among these, polycondensates of dibutylamine, 1,3,5-triazine and N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1, 1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2 , 2,6,6-tetramethyl-4-piperidyl) imino}], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, etc. A molecular weight (Mn) of 2,000 to 5,000 is preferred.

Examples of preferable hindered amine compounds include the following Specific Example 1 (Sunlizer HA-622, manufactured by Sort Co., Ltd.) and Specific Example 2.

Among the above specific examples, CHIMASSORB 2020FDL (CAS-No. 192268-64-7), CHIMASSORB 944FDL (CAS-No. 71878-19-8), and TINUVIN 770DF manufactured by BASF (former Ciba Specialty Chemicals) (CAS-No. 52829-07-9), Siasorb UV-3346 (CAS-No. 82541-48-7) and Siasorb UV-3529 (CAS-No. 193098-40-7) manufactured by Sun Chemical Co., Ltd. It is suitable because it is commercially available and has excellent availability.

In addition, although the above-mentioned hindered amine compound may be obtained commercially as described above, a synthetically produced compound may be used. There is no restriction | limiting in particular as a synthesis | combining method of a hindered amine type compound, It can synthesize | combine by the method in normal organic synthesis. Moreover, as a production | generation method, the method using distillation, recrystallization, reprecipitation, and a filter agent and adsorption agent can be used suitably. Furthermore, the commercially available products that are available on the market at low cost may be a mixture instead of the hindered amine compound alone, but in the present embodiment, the commercially available product is obtained by the production method, composition, melting point, acid value. It can be used regardless of the above.

The hindered amine compound used in the present embodiment may be a low molecular weight polymer or a polymer having a repeating unit, but a hindered amine compound is provided in the vicinity of the interface between the active energy ray cured layer and the film substrate. A high molecular weight is preferable for uneven distribution. On the other hand, if the molecular weight is too high, the compatibility with the film substrate (for example, cellulose acylate) is insufficient, and the haze of the film is increased.

The molecular weight of the hindered amine compound is preferably 300 to 100,000, more preferably 700 to 50,000, and particularly preferably 2,000 to 30,000.

In addition, the hindered amine compound used in this embodiment is preferably dissolved in 0.01% by mass or more in a ketone solvent. By using such a hindered amine compound, the hindered amine compound added to the film substrate when producing the polarizing plate protective film of the present embodiment is preferably used when the active energy ray cured layer is formed. It is preferable because the hindered amine compound is contained in the active energy ray-cured layer after being dissolved in the solvent and transferred.

When the film substrate is made of a cellulose acylate film, the hindered amine compound is preferably contained in an amount of 0.001% by mass to 5% by mass with respect to the cellulose acylate. The hindered amine compound is preferably contained in an amount of 0.001% by mass or more and 2% by mass or less, more preferably 0.01% by mass or more and 1.5% by mass or less, and 0.05% by mass with respect to cellulose acylate. It is particularly preferable that the content is from 1.0% to 1.0% by mass.

When the content of the hindered amine compound is less than 0.001% by mass with respect to the cellulose acylate film, sufficient adhesion between the active energy ray-curable functional layer and the cellulose acylate film cannot be ensured. In addition, in the case of 5 mass% or less, it becomes difficult to produce a hindered amine type bleed out, and it is preferable from a viewpoint of the improvement of the polarizing performance of a polarizing plate.

(Polymer containing repeating units derived from the monomer represented by formula (P))
A film base material may contain the polymer containing the repeating unit derived from the monomer represented with the following general formula (P) as a durability improvement agent of a polarizer.

In general formula (P), R ¹ represents a hydrogen atom or an aliphatic group having 1 to 4 carbon atoms. R ¹ is not particularly limited, but is preferably a hydrogen atom, a methyl group, or an ethyl group.

R ² represents a substituent, and the substituent is preferably an aliphatic group or an aromatic group. R ² is not particularly limited, but the aliphatic group is preferably an alkyl group, an alkenyl group, an alkynyl group or a cycloalkyl group, more preferably an alkyl group having 1 to 6 carbon atoms, a methyl group, an ethyl group or a propyl group. A butyl group is more preferable, and a methyl group and a t-butyl group are particularly preferable. As the aromatic group, a phenyl group, a naphthyl group, and a biphenyl group are preferable, and a phenyl group is particularly preferable.

n represents an integer of 0 to 4, preferably 0 to 2, and more preferably 0 to 1. Note that when n is 0, the substituent R ² does not exist, but in the chemical formula, this means that a hydrogen atom is sufficient.

(A) represents an atomic group necessary for forming a 5- or 6-membered ring, and is preferably a 5- or 6-membered aromatic ring. The aromatic ring in this specification is a concept including an aromatic ring containing no hetero atom and a saturated / unsaturated hetero ring containing a hetero atom.

In view of the effect of suppressing the moisture permeability and moisture content of the film, the polymer represented by the general formula (P) preferably has a mass average molecular weight of 200 to 10,000, more preferably 300 to 8,000, Particularly preferred is 400 to 4,000. From the effect of suppressing the moisture permeability and moisture content of the film, an improvement in compatibility with the cellulose acylate can be expected when it is not more than the upper limit.

Unless otherwise specified, the molecular weight and dispersity are values measured using a GPC (gel filtration chromatography) method, and the molecular weight can be measured by a polystyrene-reduced mass average molecular weight.

The gel packed in the column used in the GPC method is preferably a gel having an aromatic compound as a repeating unit, and examples thereof include a gel made of a styrene-divinylbenzene copolymer. Two to six columns are preferably connected and used. Examples of the solvent used include ether solvents such as tetrahydrofuran and amide solvents such as N-methylpyrrolidinone. The measurement is preferably performed at a solvent flow rate in the range of 0.1 to 2 mL / min, and most preferably in the range of 0.5 to 1.5 mL / min. By performing the measurement within this range, the apparatus is not loaded and the measurement can be performed more efficiently. The measurement temperature is preferably 10 to 50 ° C, most preferably 20 to 40 ° C. The column and carrier to be used can be appropriately selected according to the physical properties of the polymer compound to be measured.

The addition amount of the polymer represented by the general formula (P) is not particularly limited, but is preferably 0.1 to 100 parts by mass with respect to 100 parts by mass of the resin forming the film substrate, and 0.5 to The amount is more preferably 50 parts by mass, and particularly preferably 1.0 to 30 parts by mass.

Hereinafter, although the specific example of the polymer which has a repeating unit derived from the monomer represented by general formula (P) is shown, this invention is limited to this and is not interpreted. In addition, the following structural formula has shown the chemical structure of the repeating unit of the main component, and its structural ratio, and it is as above-mentioned that the other component may be contained.

The polymer of the present specification includes not only a polymer that is a general polymer compound in which a large number of monomers are polymerized, but also an oligomer that is a compound having a molecular weight of about several hundreds, in which several monomers are polymerized, for example. means. Unless otherwise specified, polymers, copolymers or copolymers are also included.

(Organic acid)
The film substrate may contain an organic acid as a polarizer durability improver. The molecular weight of the organic acid is preferably 200 to 1000, more preferably 250 to 800, and particularly preferably 280 to 500. The organic acid preferably includes an aromatic ring structure, preferably includes an aryl group having 6 to 12 carbon atoms, and particularly preferably includes a phenyl group. The aromatic ring structure of the organic acid may form a condensed ring with other rings. The aromatic ring structure of the organic acid may have a substituent, but is preferably a halogen atom or an alkyl group, more preferably a halogen atom or an alkyl group having 1 to 6 carbon atoms, and a chlorine atom. Or it is especially preferable that it is a methyl group. The organic acid is preferably represented by the following general formula (Q).

In the general formula (Q), R ²⁶ represents an aryl group, and R ²⁷ and R ²⁸ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ²⁶ and R ²⁷ may each have a substituent. R ²⁶ is preferably an aryl group having 6 to 18 carbon atoms, more preferably an aryl group having 6 to 12 carbon atoms, and particularly preferably a phenyl group. R ²⁷ and R ²⁸ are preferably each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms (including a cycloalkyl group) or an aryl group having 6 to 12 carbon atoms. It is more preferably an alkyl group of 6 (including a cycloalkyl group) or a phenyl group, and particularly preferably a hydrogen atom, a methyl group, an ethyl group, a cyclohexane group or a phenyl group. Specific examples of the organic acid represented by the general formula (Q) are illustrated below, but the present invention is not limited to the following.

The content of the organic acid is preferably 1 to 20% by mass with respect to the main component resin constituting the film substrate.

(Compound represented by formula (S))
A film base material may contain the compound represented by the following general formula (S) as a durability improvement agent of a polarizer.

In the general formula (S), R ¹ represents a hydrogen atom or a substituent, and R ² represents a substituent represented by the following general formula (a). n1 represents an integer of 0 to 4. When n1 is 2 or more, the plurality of R ¹ may be the same as or different from each other. n2 represents an integer of 1 to 5. When n2 is 2 or more, the plurality of R ² may be the same as or different from each other.

In general formula (a), A represents a substituted or unsubstituted aromatic ring. R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a substituent represented by the following general formula (b). R ⁵ represents a single bond or an alkylene group having 1 to 5 carbon atoms. X represents a substituted or unsubstituted aromatic ring. n3 represents an integer of 0 to 10. When n3 is 2 or more, the plurality of R ⁵ and X may be the same as or different from each other.

In general formula (b), X represents a substituted or unsubstituted aromatic ring. R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. n5 represents an integer of 1 to 11. When n5 is 2 or more, the plurality of R ⁶ , R ⁷ , R ⁸ and X may be the same as or different from each other.

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

The weight average molecular weight of the compound represented by the general formula (S) is preferably from 200 to 1,200, more preferably from 250 to 1,000, and particularly preferably from 300 to 800.

The addition amount of the compound represented by the general formula (S) is not particularly limited, but is preferably from 0.1 to 100 parts by mass with respect to 100 parts by mass of the film base material, and is preferably from 0.2 to 80 The amount is more preferably part by mass, and particularly preferably 0.3 to 60 parts by mass.

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

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

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

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

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

The in-plane retardation value Ro of the film base is preferably 0 to 5 nm, and the retardation value Rth in the thickness direction is preferably in the range of −10 to 10 nm. Further, Rth is preferably in the range of -5 to 5 nm. Alternatively, the retardation Ro is preferably in the range of 30 to 200 nm, and more preferably in the range of 30 to 90 nm. The retardation Rth in the thickness direction is preferably in the range of 70 to 300 nm.

The in-plane retardation Ro value is defined by the following formula (I), and the retardation value Rth in the thickness direction is defined by the following formula (II).
Formula (I) Ro = (nx−ny) × d
Formula (II) Rth = {(nx + ny) / 2−nz} × d
(Where nx is the refractive index in the slow axis direction in the plane of the film base, ny is the refractive index in the direction perpendicular to the slow axis in the plane of the film base, and nz is the thickness direction of the film base) (Refractive index, d represents the thickness (nm) of the film substrate, respectively.)

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

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

(Organic solvent)
An organic solvent useful for forming a resin solution (dope composition) in the case of producing a cellulose ester film by a solution casting film forming method described later is one that can simultaneously dissolve a cellulose ester resin and other additives. Can be used without limitation. For example, as a chlorinated organic solvent, methylene chloride, as a non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, etc. Can, methylene chloride, methyl acetate, ethyl acetate, may be used preferably acetone. The solvent is preferably a dope composition in which a total of 15 to 45 mass% of cellulose ester resin and other additives are dissolved.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[Method for producing obliquely stretched film]
The aforementioned λ / 4 film can be produced by the following oblique stretching. The oblique stretched film can be produced by producing a stretched film having a slow axis at an angle of more than 0 ° and less than 90 ° with respect to the film extension direction. In addition, as a non-stretched film before diagonal stretching, the well-known film mentioned above is used.

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

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

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

FIG. 2 is a plan view schematically showing a schematic configuration of a manufacturing apparatus 51 for an obliquely stretched film. The manufacturing apparatus 51 includes, in order from the upstream side in the transport direction of the long film, a film feeding unit 52, a transport direction changing unit 53, a guide roll 54, a stretching unit 55, a guide roll 56, and a transport direction changing unit 57. A film cutting device 58 and a film take-up unit 59 are provided. Details of the extending portion 55 will be described later.

The film feeding unit 52 feeds the above-mentioned long film and supplies it to the stretching unit 55. The film feeding portion 52 may be configured separately from the long film forming apparatus or may be configured integrally. In the case of the former, a long film is wound around a core once after film formation, and a wound body (long film original fabric) is loaded into the film unwinding part 52 so that the film unwinds from the film unwinding part 52. The film is paid out. On the other hand, in the latter case, the film feeding portion 52 is fed to the stretching portion 55 without winding the long film after the long film is formed.

The conveyance direction changing unit 53 changes the conveyance direction of the long film fed from the film feeding unit 52 to a direction toward the entrance of the stretching unit 55 as an oblique stretching tenter. Such a conveyance direction change part 53 is comprised including the turntable which rotates the turn bar in the surface parallel to a film, and the turn bar which changes a conveyance direction by folding, for example, conveying a film.

By changing the transport direction of the long film as described above by the transport direction changing unit 53, the width of the entire manufacturing apparatus 51 can be made narrower, and the film feed position and angle are finely controlled. Thus, it is possible to obtain a long obliquely stretched film with small variations in film thickness and optical value. In addition, if the film feeding unit 52 and the conveyance direction changing unit 53 are movable (slidable and turnable), the left and right clips (gripping tools) sandwiching both ends in the width direction of the long film in the stretching unit 55 are arranged. It is possible to effectively prevent the biting into the film.

In addition, the above-described film feeding unit 52 may be slidable and turnable so that a long film can be fed at a predetermined angle with respect to the entrance of the stretching unit 55. In this case, it is also possible to adopt a configuration in which the installation of the conveyance direction changing unit 53 is omitted.

At least one guide roll 54 is provided on the upstream side of the stretching portion 55 in order to stabilize the track during running of the long film. The guide roll 54 may be composed of a pair of upper and lower rolls sandwiching the film, or may be composed of a plurality of roll pairs. The guide roll 54 closest to the entrance of the extending portion 55 is a driven roll that guides the travel of the film, and is rotatably supported by bearings (not shown). As the material of the guide roll 54, a known material can be used. In order to prevent the film from being damaged, it is preferable to reduce the weight of the guide roll 54 by applying a ceramic coat on the surface of the guide roll 54 or applying chrome plating to a light metal such as aluminum.

Further, it is preferable that one of the rolls upstream of the guide roll 54 closest to the entrance of the extending portion 55 is nipped by pressing the rubber roll. By setting it as such a nip roll, it becomes possible to suppress the fluctuation | variation of the drawing tension | tensile_strength in the flow direction of a film.

A pair of bearing portions at both ends (left and right) of the guide roll 54 closest to the entrance of the extending portion 55 includes a first tension detection device as a film tension detection device for detecting the tension generated in the film in the roll, A second tension detecting device is provided. For example, a load cell can be used as the film tension detection device. As the load cell, a known tensile or compression type can be used. A load cell is a device that detects a load acting on an applied point by converting it into an electrical signal using a strain gauge attached to the strain generating body.

The load cell is installed in the left and right bearing portions of the guide roll 54 closest to the entrance of the extending portion 55, so that the force of the running film on the roll, that is, in the film traveling direction generated in the vicinity of both side edges of the film. The tension is detected independently on the left and right. In addition, a strain gauge may be directly attached to a support that constitutes the bearing portion of the roll, and a load, that is, a film tension may be detected based on the strain generated in the support. The relationship between the generated strain and the film tension is measured in advance and is known.

When the position and the transport direction of the film supplied from the film feeding unit 52 or the transport direction changing unit 53 to the stretching unit 55 are deviated from the position toward the entrance of the stretching unit 55 and the transport direction, according to this misalignment amount, A difference occurs in the tension in the vicinity of both side edges of the film in the guide roll 54 closest to the entrance of the stretching portion 55. Therefore, by providing the above-described film tension detecting device and detecting the above-described tension difference, the degree of the deviation can be determined. That is, if the transport position and transport direction of the film are appropriate (if it is the position and direction toward the entrance of the stretching section 55), the load acting on the guide roll 54 is roughly uniform at both ends in the axial direction. If not appropriate, there will be a difference in film tension between left and right.

Therefore, for example, the above-described transport direction changing unit 53 changes the film position and transport direction (angle with respect to the entrance of the stretching unit 55) so that the left and right film tension differences between the guide rolls 54 closest to the entrance of the stretching unit 55 become equal. When properly adjusted, the film can be stably held by the gripping tool at the entrance of the extending portion 55, and the occurrence of obstacles such as detachment of the gripping tool can be reduced. Furthermore, the physical properties in the width direction of the film after oblique stretching by the stretching portion 55 can be stabilized.

At least one guide roll 56 is provided on the downstream side of the stretching portion 55 in order to stabilize the trajectory of the film stretched obliquely by the stretching portion 55 during travel.

The transport direction changing unit 57 changes the transport direction of the stretched film transported from the stretching unit 55 to a direction toward the film winding unit 59.

Here, in order to cope with fine adjustment of the orientation angle (the direction of the in-plane slow axis of the film) and product variations, the film traveling direction at the entrance of the stretching portion 55 and the film traveling direction at the exit of the stretching portion 55 It is necessary to adjust the angle between the two. In order to adjust the angle, the traveling direction of the formed film is changed by the transport direction changing unit 53 to guide the film to the inlet of the stretching unit 55 and / or the traveling direction of the film from the outlet of the stretching unit 55 Needs to be changed by the transport direction changing unit 57 to return the film to the direction of the film winding unit 59.

Moreover, it is preferable from the viewpoint of productivity and yield that the film formation and oblique stretching are continuously performed. When the film forming process, the oblique stretching process, and the winding process are continuously performed, the traveling direction of the film is changed by the transport direction changing unit 53 and / or the transport direction changing unit 57, and the film is formed by the film forming process and the winding process. 2, that is, as shown in FIG. 2, the traveling direction (feeding direction) of the film fed from the film feeding unit 52 and the traveling direction of the film immediately before being wound by the film winding unit 59 ( The width of the entire apparatus with respect to the film traveling direction can be reduced by matching the winding direction.

In addition, although the advancing direction of a film does not necessarily need to correspond in a film forming process and a winding process, the conveyance direction change part 53 and the film feeding part 52 and the film winding part 59 are set so that it may become a layout which does not interfere. It is preferable to change the traveling direction of the film by the transport direction changing unit 57.

The conveyance

direction changing units

53 and 57 as described above can be realized by a known method such as using an air flow roll or an air turn bar.

The film cutting device 58 cuts the film stretched by the stretching section 55 (long oblique stretched film) along the cross section including the width direction, and has a cutting member. The cutting member is composed of, for example, a scissor or a cutter (including a slitter, a strip-shaped blade (Thomson blade)), but is not limited thereto, and in addition, a rotating circular saw, a laser irradiation device, etc. It is also possible to configure.

The film take-up unit 59 takes up the film conveyed from the stretching unit 55 via the conveyance direction changing unit 57, and includes, for example, a winder device, an accumulator device, a drive device, and the like. It is preferable that the film winding unit 59 has a structure that can be slid in the lateral direction in order to adjust the film winding position.

The film take-up unit 59 can finely control the film take-up position and angle so that the film can be taken at a predetermined angle with respect to the outlet of the stretching unit 55. Thereby, it becomes possible to obtain a long obliquely stretched film with small variations in film thickness and optical value. In addition, it is possible to effectively prevent wrinkling of the film and to improve the winding property of the film, so that the film can be wound up in a long length.

The film take-up unit 59 constitutes a take-up unit that takes up the film stretched and transported by the stretch unit 55 with a certain tension. In addition, you may make it provide the take-up roll for taking up a film with fixed tension | tensile_strength between the extending | stretching part 55 and the film winding-up part 59. FIG. Further, the guide roll 56 described above may have a function as the take-up roll.

In this embodiment, the take-up tension T (N / m) of the stretched film is preferably adjusted between 100 N / m <T <300 N / m, preferably 150 N / m <T <250 N / m. When the take-up tension is 100 N / m or less, sagging and wrinkles of the film are likely to occur, and the retardation and orientation angle profile in the film width direction are also deteriorated. On the other hand, when the take-up tension is 300 N / m or more, the variation of the orientation angle in the film width direction is deteriorated, and the width yield (taken efficiency in the width direction) is deteriorated.

In the present embodiment, it is preferable to control the fluctuation of the take-up tension T with an accuracy of less than ± 5%, preferably less than ± 3%. When the variation in the take-up tension T is ± 5% or more, the variation in the optical characteristics in the width direction and the flow direction (conveying direction) increases. As a method for controlling the fluctuation of the take-up tension T within the above range, the load applied to the first roll (guide roll 56) on the outlet side of the stretching section 55, that is, the film tension is measured, and the value becomes constant. Thus, there is a method of controlling the rotation speed of the take-up roll or the take-up roll of the film take-up portion 59 by a general PID control method. Examples of the method for measuring the load include a method in which a load cell is attached to the bearing portion of the guide roll 56 and the load applied to the guide roll 56, that is, the tension of the film is measured. As the load cell, a known tensile type or compression type can be used.

The stretched film is released from the exit of the stretching section 55 after being gripped by the gripping tool of the stretching section 55, and both ends (both sides) of the film gripped by the gripping tool are trimmed as necessary. Then, the film is cut into a predetermined length by the film cutting device 58, and is wound up around a winding core (winding roll) sequentially to form a wound body of an obliquely stretched film.

Further, before winding the obliquely stretched film, for the purpose of preventing blocking between the films, the masking film may be overlapped with the obliquely stretched film and simultaneously wound, or at least one of the obliquely stretched films overlapping by winding (preferably May be wound up with a tape or the like attached to both ends. The masking film is not particularly limited as long as it can protect the obliquely stretched film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.

(Details of stretched part)
Next, the detail of the extending | stretching part 55 mentioned above is demonstrated. FIG. 3 is a plan view schematically showing an example of the rail pattern of the extending portion 55. However, this is an example, and the configuration of the extending portion 55 is not limited to this.

The production of the long obliquely stretched film in the present embodiment is performed using a tenter (an obliquely stretching machine) capable of oblique stretching as the stretching part 55. This tenter is an apparatus that heats a long film to an arbitrary temperature at which it can be stretched and obliquely stretches it. This tenter includes a heating zone Z, a pair of rails Ri and Ro on the left and right, and a number of gripping tools Ci and Co that travel along the rails Ri and Ro to convey a film (in FIG. 3, a set of gripping tools). Only). Details of the heating zone Z will be described later. Each of the rails Ri and Ro is configured by connecting a plurality of rail portions with connecting portions (white circles in FIG. 3 are examples of connecting portions). The gripping tool Ci / Co is composed of a clip that grips both ends of the film in the width direction.

In FIG. 3, the feeding direction D1 of the long film is different from the winding direction D2 of the long oblique stretched film after stretching, and forms a feeding angle θi with the winding direction D2. The feeding angle θi can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °.

Thus, since the feeding direction D1 and the winding direction D2 are different, the rail pattern of the tenter has an asymmetric shape on the left and right. And a rail pattern can be adjusted now manually or automatically according to the orientation angle | corner (theta) given to the long diagonally stretched film which should be manufactured, a draw ratio, etc. FIG. In the oblique stretching machine used in the manufacturing method of the present embodiment, it is preferable that the positions of the rail portions and the rail connecting portions constituting the rails Ri and Ro can be freely set and the rail pattern can be arbitrarily changed.

In the present embodiment, the tenter gripping tool Ci · Co travels at a constant speed with a constant interval from the front and rear gripping tools Ci · Co. The traveling speed of the gripping tool Ci / Co can be selected as appropriate, but is usually 1 to 150 m / min. The difference in travel speed between the pair of left and right grippers Ci / Co is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed. This is because if there is a difference in the traveling speed on the left and right of the film at the exit of the stretching process, wrinkles and shifts will occur at the exit of the stretching process, so the speed difference between the left and right grippers Ci / Co is substantially the same speed. Is required. In general tenter devices, etc., there are speed irregularities that occur on the order of seconds or less depending on the period of the sprocket teeth that drive the chain, the frequency of the drive motor, etc. This does not correspond to the speed difference described in the embodiment of the invention.

In the oblique stretching machine used in the manufacturing method of the present embodiment, a high bending rate is often required for the rail that regulates the trajectory of the gripping tool, particularly at a location where the film is transported obliquely. In order to avoid interference between gripping tools due to sudden bending or local stress concentration, it is desirable that the trajectory of the gripping tool draws a curve at the bent portion.

As described above, the obliquely stretched tenter used for imparting the oblique orientation to the long film can freely set the orientation angle of the film by changing the rail pattern in various ways, and further, the orientation axis of the film It is preferred that the tenter be capable of orienting the (slow axis) in the left and right direction with high precision across the film width direction and controlling the film thickness and retardation with high precision.

Next, the stretching operation in the stretching unit 55 will be described. Both ends of the long film are gripped by the left and right grippers Ci · Co, and are conveyed in the heating zone Z as the grippers Ci • Co travel. The left and right gripping tools Ci and Co are opposed to a direction substantially perpendicular to the film traveling direction (feeding direction D1) at the entrance portion (position A in the drawing) of the extending portion 55, and the left and right asymmetric rails. Each travels on Ri and Ro, and the film gripped at the exit portion (position B in the figure) at the end of stretching is released. The film released from the gripping tool Ci · Co is wound around the core by the film winding portion 59 described above. Each of the pair of rails Ri and Ro has an endless continuous track, and the grippers Ci and Co that have released the film at the exit portion of the tenter travel on the outer rail and sequentially return to the entrance portion. It is supposed to be.

At this time, since the rails Ri and Ro are asymmetrical in the left and right, in the example of FIG. 3, the left and right gripping tools Ci and Co, which are opposed to each other at the position A in the figure, move along the rails Ri and Ro. The gripping tool Ci traveling on the Ri side (in-course side) has a positional relationship preceding the gripping tool Co traveling on the rail Ro side (out-course side).

That is, of the gripping tools Ci and Co that are opposed to the film feeding direction D1 at the position A in the figure, one gripping tool Ci is first in position B at the end of film stretching. When it reaches, the straight line connecting the gripping tools Ci and Co is inclined by an angle θL with respect to the direction substantially perpendicular to the film winding direction D2. With the above operation, the long film is obliquely stretched at an angle of θL with respect to the width direction. Here, “substantially vertical” indicates that the angle is in a range of 90 ± 1 °.

Next, the details of the heating zone Z will be described. The heating zone Z of the extending section 55 is composed of a preheating zone Z1, an extending zone Z2, and a heat setting zone Z3. In the stretching unit 55, the film gripped by the gripping tool Ci / Co passes through the preheating zone Z1, the stretching zone Z2, and the heat fixing zone Z3 in this order. In the present embodiment, the preheating zone Z1 and the stretching zone Z2 are separated by a partition, and the stretching zone Z2 and the heat fixing zone Z3 are separated by a partition.

The preheating zone Z1 refers to a section in which the gripping tool Ci / Co that grips both ends of the film travels at the left and right (in the film width direction) at a constant interval at the entrance of the heating zone Z.

The stretching zone Z2 refers to a section from when the gap between the gripping tools Ci and Co that grips both ends of the film opens until a predetermined gap is reached. At this time, the oblique stretching as described above is performed, but the stretching may be performed in the longitudinal direction or the transverse direction before and after the oblique stretching as necessary.

The heat setting zone Z3 refers to a section after the stretching zone Z2 in which the interval between the gripping tools Ci and Co is constant, and the gripping tools Ci and Co at both ends travel in parallel with each other. .

The stretched film passes through the heat setting zone Z3 and then passes through a section (cooling zone) in which the temperature in the zone is set to be equal to or lower than the glass transition temperature Tg (° C.) of the thermoplastic resin constituting the film. May be. At this time, considering the shrinkage of the film due to cooling, a rail pattern that narrows the gap between the gripping tools Ci and Co facing each other in advance may be used.

The temperature of the preheating zone Z1 is Tg to Tg + 30 ° C., the temperature of the stretching zone Z2 is Tg to Tg + 30 ° C., and the temperature of the heat setting zone Z3 and the cooling zone is Tg-30 to Tg + 20 ° C. with respect to the glass transition temperature Tg of the thermoplastic resin. It is preferable to set.

The lengths of the preheating zone Z1, the stretching zone Z2, and the heat setting zone Z3 can be appropriately selected. The length of the preheating zone Z1 is usually 100 to 150% of the length of the stretching zone Z2, and the length of the heat setting zone Z3 The length is usually 50 to 100%.

When the width of the film before stretching is Wo (mm) and the width of the film after stretching is W (mm), the draw ratio R (W / Wo) in the stretching step is preferably 1.3 to 3. 0, more preferably 1.5 to 2.8. When the draw ratio is in this range, the thickness unevenness in the width direction of the film is preferably reduced. In the stretching zone Z2 of the oblique stretching tenter, if the stretching temperature is differentiated in the width direction, the width direction thickness unevenness can be further improved. In addition, said draw ratio R is equal to a magnification (W2 / W1) when the interval W1 between both ends of the clip held at the tenter inlet portion becomes the interval W2 at the tenter outlet portion.

Note that the method of oblique stretching in the stretching portion 55 is not limited to the above-described method. For example, the oblique stretching may be performed by simultaneous biaxial stretching as disclosed in Japanese Patent Application Laid-Open No. 2008-23775. Good. Note that simultaneous biaxial stretching means that both ends in the width direction of the supplied long film are gripped by each gripping tool, and the long film is transported while moving each gripping tool, and the long film is transported. This is a method of stretching a long film in an oblique direction with respect to the width direction by making the moving speed of one gripping tool different from the moving speed of the other gripping tool while keeping the direction constant. In addition, oblique stretching may be performed by a technique disclosed in Japanese Patent Application Laid-Open No. 2011-11434.

(Physical properties of film substrate)
The thickness of the film substrate is preferably 5 to 200 μm, more preferably 5 to 80 μm. The length of the film substrate is preferably 500 to 10000 m, more preferably 1000 to 8000 m. By setting it as the range of the said length, it is excellent in the processability in application | coating, such as a hard-coat layer, and the handleability of film base itself.

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

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

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

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

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

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

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

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

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

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

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

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

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

〔Polarizer〕
Next, a polarizing plate using the optical film of this embodiment will be described. The polarizing plate can be produced by a general method.

For example, the optical film (for example, hard coat film) of the present embodiment is subjected to alkali saponification treatment, and the treated optical film is completely saponified on one surface of a polarizing film (polarizer) produced by dipping and stretching in an iodine solution. It is preferable to bond together using an aqueous polyvinyl alcohol solution.

The optical film may be bonded to the other surface of the polarizer, or a film substrate such as the cellulose ester film described above may be bonded. The thickness of the film substrate to be bonded to the other surface is preferably in the range of 5 to 80 μm from the viewpoint of adjusting smoothness and curl balance and further enhancing the effect of preventing winding deviation.

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

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

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

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

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

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

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

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

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

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

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

Bonding of the optical film and the front plate can be performed as follows, for example. First, a filler is prepared. And a filler is applied to the surface of the hard coat layer of an optical film, and a front board is piled up on the coating film of a filler. In this state, the filler is cured by light irradiation or the like, and the optical film and the front plate are bonded together. When the filler is applied to the surface of the hard coat layer, the surface free energy of the hard coat layer is set to 30 mN / m or more, so that the filler spreads uniformly without being repelled at the end of the hard coat layer. An image display device that maintains the state and is excellent in visibility can be obtained.

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

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

<Preparation of Dope Composition 1>
(Cellulose ester resin)
Cellulose triacetate A (cellulose triacetate synthesized from linter cotton, acetyl group substitution degree 2.88, Mn = 14,000)
90 parts by mass (additive)
Ester Represented by General Formula (X) (Exemplary Compound X-1) 5 parts by mass Ester Represented by General Formula (X) (Exemplary Compound X-12) 4 parts by mass (Antioxidant)
Hindered amine compounds (CHIMASSORB 944FDL)
0.5 parts by mass (UV absorber)
TINUVIN 928 (manufactured by BASF Japan Ltd.) 3 parts by mass (fine particles)
Silicon dioxide dispersion dilution 4 parts by mass (solvent)
Methylene chloride 432 parts by mass Ethanol 38 parts by mass The above was put into a sealed container, heated and stirred, and dissolved completely. Azumi filter paper No. Azumi filter paper No. 24 was used to prepare a dope (dope composition 1).

Next, the belt was cast evenly on a stainless steel band support using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100% by mass, and the stainless steel band support was peeled off. The cellulose ester film web was evaporated at 35 ° C., slit to 1.15 m width, and dried at a drying temperature of 140 ° C. while being stretched 1.15 times in the TD direction (film width direction) with a tenter. I let you. Then, it was dried for 15 minutes while being transported in a drying device at 120 ° C. with a number of rollers, slitted to a width of 1.3 m, knurled with a width of 10 mm and a height of 5 μm at both ends of the film, and wound around a core. The cellulose ester film 1 was obtained. The film thickness of the cellulose ester film 1 was 25 μm, and the winding length was 5000 m.

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

[Preparation of optical film 1]
The following hard coat layer composition 1 is applied on the A side (the surface not in contact with the casting belt) of the produced cellulose ester film 1 using an extrusion coater, and the constant rate drying section temperature is reduced to 50 ° C. After drying at a rate drying section temperature of 50 ° C., while purging with nitrogen so that the oxygen concentration is 1.0 volume% or less, the illuminance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp and the irradiation amount is 0 The coating layer was cured at ² J / cm ² to form a hard coat layer 1 having a dry film thickness of 4 μm, which was wound up into a roll to produce an optical film 1.

<< Hard Coat Layer Composition 1 >>
<Composition of hard coat layer composition 1>
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.)
100 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (additive)
Fluorine-siloxane graft compound (35% by mass) 2 parts by mass (solvent)
Propylene glycol monomethyl ether 20 parts by weight Methyl acetate 30 parts by weight Methyl ethyl ketone 70 parts by weight

<Preparation of fluorine-siloxane graft compound>
The commercial name of the material used for the preparation of the fluorine-siloxane graft compound is shown.

Radical polymerizable fluororesin (A): Cefal coat CF-803 (hydroxy group number 60, number average molecular weight 15000; manufactured by Central Glass Co., Ltd.)
One-end radically polymerizable polysiloxane (B): Silaplane FM-0721 (number average molecular weight 5000; manufactured by Chisso Corporation)
Radical polymerization initiator: Perbutyl O (t-butylperoxy-2-ethylhexanoate; manufactured by NOF Corporation)
Curing agent: Sumidur N3200 (biuret type prepolymer of hexamethylene diisocyanate; manufactured by Sumika Bayer Urethane Co., Ltd.)

(Synthesis of radical polymerizable fluororesin)
A glass reactor equipped with a mechanical stirrer, a thermometer, a condenser and a dry nitrogen gas inlet was added to cefal coat CF-803 (1554 parts by mass), xylene (233 parts by mass), and 2-isocyanatoethyl methacrylate (6 3 parts by mass) and heated to 80 ° C. in a dry nitrogen atmosphere. After reacting at 80 ° C. for 2 hours and confirming that the absorption of isocyanate disappeared by the infrared absorption spectrum of the sampled material, the reaction mixture was taken out to obtain 50% by mass of a radically polymerizable fluororesin via a urethane bond. .

(Preparation of fluorine-siloxane graft compound)
In a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet, the above synthesized radical polymerizable fluororesin (26.1 parts by mass), xylene (19.5 parts by mass), acetic acid n-butyl (16.3 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 (1 8 parts by mass), FM-0721 (5.2 parts by mass), and perbutyl O (0.1 parts by mass) were heated to 90 ° C. in a nitrogen atmosphere, and held at 90 ° C. for 2 hours. Perbutyl O (0.1 part) was added, and the mixture was further maintained at 90 ° C. for 5 hours to obtain a 35 mass% fluorine-siloxane graft compound solution having a weight average molecular weight of 171,000. The weight average molecular weight was determined by GPC. The mass% of the fluorine-siloxane graft compound was determined by HPLC (liquid chromatography).

[Alkali treatment]
Next, the produced optical film 1 was subjected to alkali treatment under the following alkali treatment condition A.
(Alkali treatment condition A)
Saponification process 2 mol / L-NaOH 50 ° C. 120 seconds Washing process Water 25 ° C. 120 seconds Drying process 100 ° C. 60 seconds

<Example 2>
In production of the optical film 1 of Example 1, the hard coat layer composition 1 was changed to the following hard coat layer composition 2. Otherwise, the optical film 2 was produced in the same manner as in the production of the optical film 1. Then, the optical film 2 was subjected to alkali treatment under the same conditions as the alkali treatment condition A of Example 1.

<< Hard Coat Layer Composition 2 >>
<Composition of hard coat layer composition 2>
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.)
100 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (additive)
KF-351A (polyether-modified silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd.)
0.5 parts by mass KF-642 (polyether-modified silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd.)
0.25 parts by weight Emulgen 404 (manufactured by Kao Corporation) 1.8 parts by weight V-8804 (dispersion of polymer silane coupling agent-coated silica, manufactured by JGC Catalysts & Chemicals Co., Ltd.)
1.4 parts by mass (solvent)
Normal propanol 20 parts by mass Methyl acetate 30 parts by mass Methyl ethyl ketone 70 parts by mass

<Example 3>
The optical film 2 of Example 2 was subjected to alkali treatment by changing the alkali treatment condition A to the following alkali treatment condition B. The rest is the same as in the second embodiment.
(Alkaline treatment condition B)
Saponification process 2mol / L-NaOH 50 ° C 180 seconds Washing process Water 25 ° C 120 seconds Drying process 100 ° C 60 seconds

<Example 4>
An optical film 3 was produced in the same manner as in the production of the optical film 1 of Example 1, except that the content of V-8804 contained in the hard coat layer composition 2 was changed to 2.5 parts by mass. The optical film 3 was subjected to alkali treatment under the same alkali treatment condition B as in Example 3.

<Comparative Example 1>
An optical film 4 was produced in the same manner as in the production of the optical film 1 of Example 1 except that the hindered amine compound was not added to the dope composition 1. Then, the optical film 4 was subjected to alkali treatment under the same alkali treatment condition A as in Example 1.

<Comparative example 2>
The optical film 1 produced in Example 1 was subjected to alkali treatment by changing the alkali treatment condition to the following alkali treatment condition C.
(Alkali treatment condition C)
Saponification process 2 mol / L-NaOH 50 ° C. 60 seconds Water washing process Water 25 ° C. 120 seconds Drying process 100 ° C. 60 seconds

<Example 5>
The dope composition 1 used for the production of the optical film 1 of Example 1 was changed to the following dope composition 2. Otherwise, the optical film 5 was produced in the same manner as in the production of the optical film 1. Then, the optical film 5 was subjected to alkali treatment under the same alkali treatment condition A as in Example 1.

<Composition of dope composition 2>
(Cellulose ester resin)
Cellulose triacetate A (cellulose triacetate synthesized from linter cotton, acetyl group substitution degree 2.88, Mn = 14,000)
90 parts by mass (additive)
Ester Represented by General Formula (X) (Exemplary Compound X-1) 5 parts by mass Ester Represented by General Formula (X) (Exemplary Compound X-12) 4 parts by mass (polarizer durability improving agent)
Polymer containing repeating unit derived from monomer represented by general formula (P) (P-02)
9 parts by weight (UV absorber)
TINUVIN 928 (manufactured by BASF Japan Ltd.) 3 parts by mass (fine particles)
Silicon dioxide dispersion dilution 4 parts by mass (solvent)
Methylene chloride 432 parts by mass Ethanol 38 parts by mass

<Example 6>
In the production of the optical film 5 of Example 5, the hard coat layer composition 1 was changed to the hard coat layer composition 2 of Example 2. Otherwise, the optical film 6 was produced in the same manner as in the production of the optical film 5. Then, the optical film 6 was subjected to alkali treatment under the same alkali treatment condition A as in Example 5.

<Example 7>
The optical film 6 of Example 6 was alkali-treated by changing the alkali treatment condition to the same alkali condition B as in Example 3. Other than that is the same as in Example 6.

<Example 8>
An optical film 7 was produced in the same manner as in the production of the optical film 5 of Example 5, except that the content of V-8804 contained in the hard coat layer composition 2 was changed to 2.5 parts by mass. The optical film 7 was subjected to alkali treatment under the same alkali treatment condition B as in Example 7.

<Comparative Example 3>
The optical film 8 was prepared in the same manner as in the production of the optical film 5 of Example 5 except that the polymer containing the repeating unit derived from the monomer represented by the general formula (P) was not added to the dope composition 2. Produced. The optical film 8 was subjected to alkali treatment under the same alkali treatment condition A as in Example 5.

<Comparative example 4>
The optical film 5 produced in Example 5 was subjected to alkali treatment by changing the alkali treatment condition to the same alkali treatment condition C as in Comparative Example 2.

<Example 9>
The dope composition 1 used for the production of the optical film 1 of Example 1 was changed to the following dope composition 3. Otherwise, the optical film 9 was produced in the same manner as in the production of the optical film 1. Then, the optical film 9 was subjected to alkali treatment under the same alkali treatment condition A as in Example 1.

<Composition of dope composition 3>
(Cellulose ester resin)
Cellulose triacetate A (cellulose triacetate synthesized from linter cotton, acetyl group substitution degree 2.88, Mn = 14,000)
90 parts by mass (additive)
Ester Represented by General Formula (X) (Exemplary Compound X-1) 5 parts by mass Ester Represented by General Formula (X) (Exemplary Compound X-12) 4 parts by mass (polarizer durability improving agent)
5 parts by mass of organic acid (Q-3) represented by general formula (Q) (ultraviolet absorber)
TINUVIN 928 (manufactured by BASF Japan Ltd.) 3 parts by mass (fine particles)
Silicon dioxide dispersion dilution 4 parts by mass (solvent)
Methylene chloride 432 parts by mass Ethanol 38 parts by mass

<Example 10>
In the production of the optical film 9 of Example 9, the hard coat layer composition 1 was changed to the hard coat layer composition 2 of Example 2. Otherwise, the optical film 10 was produced in the same manner as in the production of the optical film 9. Then, the optical film 10 was subjected to alkali treatment under the same alkali treatment condition A as in Example 9.

<Example 11>
The optical film 10 of Example 10 was subjected to alkali treatment by changing the alkali treatment condition to the same alkali treatment condition B as in Example 3. Other than that is the same as Example 10.

<Example 12>
An optical film 11 was produced in the same manner as in the production of the optical film 9 of Example 9, except that the content of V-8804 contained in the hard coat layer composition 2 was changed to 2.5 parts by mass. The optical film 11 was subjected to alkali treatment under the same alkali treatment condition B as in Example 11.

<Comparative Example 5>
An optical film 12 was produced in the same manner as in the production of the optical film 9 of Example 9, except that the organic acid represented by the general formula (Q) was not added to the dope composition 3. Then, the optical film 12 was subjected to alkali treatment under the same alkali treatment condition A as in Example 9.

<Comparative Example 6>
The optical film 9 produced in Example 9 was subjected to alkali treatment by changing the alkali treatment condition to the same alkali treatment condition C as in Comparative Example 2.

<Example 13>
The dope composition 1 used for the production of the optical film 1 of Example 1 was changed to the following dope composition 4. Otherwise, the optical film 13 was prepared in the same manner as the optical film 1. Then, the optical film 13 was subjected to alkali treatment under the same alkali treatment condition A as in Example 1.

<Composition of dope composition 4>
(Cellulose ester resin)
Cellulose triacetate A (cellulose triacetate synthesized from linter cotton, acetyl group substitution degree 2.88, Mn = 14,000)
90 parts by mass (additive)
Ester Represented by General Formula (X) (Exemplary Compound X-1) 5 parts by mass Ester Represented by General Formula (X) (Exemplary Compound X-12) 4 parts by mass (polarizer durability improving agent)
5 parts by mass of compound (S-6) represented by general formula (S) (ultraviolet absorber)
TINUVIN 928 (manufactured by BASF Japan Ltd.) 3 parts by mass (fine particles)
Silicon dioxide dispersion dilution 4 parts by mass (solvent)
Methylene chloride 432 parts by mass Ethanol 38 parts by mass

<Example 14>
In the production of the optical film 13 of Example 13, the hard coat layer composition 1 was changed to the hard coat layer composition 2 of Example 2. Otherwise, the optical film 14 was prepared in the same manner as the optical film 13. Then, the optical film 14 was subjected to alkali treatment under the same alkali treatment condition A as in Example 13.

<Example 15>
The optical film 14 of Example 14 was subjected to alkali treatment by changing the alkali treatment condition to the same alkali treatment condition B as in Example 3. Other than that is the same as Example 14.

<Example 16>
An optical film 15 was produced in the same manner as in the production of the optical film 13 of Example 13, except that the content of V-8804 contained in the hard coat layer composition 2 was changed to 2.5 parts by mass. The optical film 15 was subjected to alkali treatment under the same alkali treatment condition B as in Example 15.

<Comparative Example 7>
An optical film 16 was produced in the same manner as in the production of the optical film 13 of Example 13, except that the compound represented by the general formula (S) was not added to the dope composition 4. The optical film 16 was subjected to alkali treatment under the same alkali treatment condition A as in Example 13.

<Comparative Example 8>
The optical film 13 produced in Example 13 was subjected to alkali treatment by changing the alkali treatment condition to the same alkali treatment condition C as in Comparative Example 2.

<Preparation of polarizing plate>
The optical film of each example and comparative example was attached to one surface of the polarizing film, and a protective film made of KC4FR-1 (manufactured by Konica Minolta Co., Ltd.) as an optical compensation film was attached to the other surface of the polarizing film. A polarizing plate was prepared. More details are as follows.

(A) Production of Polarizing Film What was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water in 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400. After melt-kneading and defoaming, it was melt-extruded from a T-die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film. The obtained PVA film had an average thickness of 25 μm, a moisture content of 4.4%, and a film width of 3 m.

Next, the obtained PVA film was continuously processed in the order of pre-swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to produce a polarizing film. That is, the PVA film was preliminarily swollen in water at a temperature of 30 ° C. for 30 seconds, and immersed in an aqueous solution having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter at a temperature of 35 ° C. for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in a 50% aqueous solution with a boric acid concentration of 4% under the condition that the tension applied to the film was 700 N / m, and the potassium iodide concentration was 40 g / liter and the boric acid concentration was 40 g / liter. Then, it was immersed in an aqueous solution having a zinc chloride concentration of 10 g / liter and a temperature of 30 ° C. for 5 minutes for fixing. Thereafter, the PVA film was taken out, dried with hot air at a temperature of 40 ° C., and further heat-treated at a temperature of 100 ° C. for 5 minutes. The obtained polarizing film had an average thickness of 13 μm, a polarizing performance of a transmittance of 43.0%, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

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

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

Step 2: An alkali saponification treatment was performed on the protective film (KC4FR-1) under the following conditions. In addition, the alkali treatment conditions at this time may be the same as the alkali treatment conditions of each Example and each Comparative Example. Next, the excess adhesive adhered to the polarizing film immersed in the polyvinyl alcohol adhesive solution in Step 1 is gently removed, and this polarizing film is sandwiched between the optical film already subjected to alkali treatment and the protective film, and laminated. did.
(Alkaline saponification treatment)
Saponification step 2.5M-KOH 50 ° C 120 seconds Water washing step Water 30 ° C 60 seconds Neutralization step 10 parts HCl 30 ° C 45 seconds Water washing step Water 30 ° C 60 seconds After saponification treatment, water washing, neutralization, water washing in this order Followed by drying at 100 ° C.

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

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

Step 5: A commercially available acrylic pressure-sensitive adhesive is applied to the protective film side of the polarizing plate prepared in Step 4 so that the thickness after drying is 25 μm, and dried in an oven at 110 ° C. for 5 minutes to form an adhesive layer. A peelable protective film was attached to the adhesive layer. This polarizing plate was cut (punched) to produce a polarizing plate.

From the above, the method for producing a polarizing plate of the present embodiment includes a step of alkali-treating an optical film under predetermined alkali treatment conditions as described above, and after the alkali treatment, the cellulose ester film of the optical film is a polarizer ( It can be said that it has the process of bonding an optical film to a polarizer so that it may become a polarizing film side.

<Production of liquid crystal display device>
Of the two polarizing plates sandwiching the liquid crystal cell of the existing liquid crystal display device, the viewing side polarizing plate was peeled off. Next, in the produced polarizing plate, the hard coat layer is on the viewing side (the cellulose ester film side is on the polarizer side), and the transmission axis of the produced polarizing plate is orthogonal to the transmission axis of the polarizing plate on the backlight side. As shown, it was arranged on the viewing side of the liquid crystal cell. And the adhesive layer of the produced said polarizing plate and the glass of the liquid crystal cell were bonded together.

Thereafter, a photo-curing resin as a filler (SVR1120, manufactured by Dexerials Co., Ltd.) was applied to the surface of the hard coat layer of the optical film, and a front plate serving as a protective part was overlaid on the coating film of the filler. Then, the photocurable resin was cured by light irradiation to form a filling layer, and the optical film and the front plate were bonded together via the filling layer to complete a liquid crystal display device.

From the above, the manufacturing method of the image display device according to the present embodiment includes the step of alkali-treating the optical film under predetermined alkali treatment conditions as described above, and the cellulose ester film of the optical film is a polarizer after the alkali treatment. (Polarizing film) side, optical film is bonded to a polarizer to form a polarizing plate, the polarizing plate is bonded to a display cell, the polarizing plate on the hard coat layer in the optical film Furthermore, it can be said that the method includes a step of forming a protective part via a photocurable resin and a step of forming a filling layer by irradiating an active energy ray to cure the photocurable resin.

[Evaluation]
(1. Measurement of surface free energy of optical film)
The contact angle of each of pure water, ethylene glycol, and polyethylene glycol with respect to the surface of the hard coat layer of the optical film of each example and each comparative example was measured five times to obtain the average value, and the above-mentioned Young-Fowkes equation Was used to determine the surface free energy of the hard coat layer. The contact angle was determined by alkali-treating the optical film and adjusting the humidity for 12 hours in an atmosphere at a temperature of 23 ° C. and a relative humidity of 55% using a contact angle meter (trade name DropMaster DM100, manufactured by Kyowa Interface Science Co., Ltd.). It was measured.

(2. Light-resistant adhesion evaluation between film base and hard coat layer)
The optical films of each of the examples and comparative examples thus produced were irradiated with light for 100 hours in an environment of 42 ° C. and 50% relative humidity using a UV auto fade meter U48AU manufactured by Suga Test Instruments Co., Ltd.

Next, the optical film was conditioned for 12 hours under conditions of a temperature of 23 ° C. and a relative humidity of 55%. Then, on the surface having the hard coat layer, 11 vertical and 11 horizontal cuts are made at 1 mm intervals in a grid pattern using a cutter knife, and a total of 100 square squares are engraved on the surface. After pressure-bonding a polyester adhesive tape (No. 31B) manufactured by Nitto Denko Corporation, the tape was quickly peeled off in the vertical direction. After crimping and peeling three times at the same location, the number of squares peeled off was counted and evaluated according to the following criteria.
<Evaluation criteria>
○: There is no peeling of the hard coat layer from the cellulose ester film.
X: Peeling of the hard coat layer from the cellulose ester film occurs, which is a practically problematic level.

(3. Evaluation of durability of polarizer)
About the produced polarizing plate, the following durability tests were done and durability of the polarizer was evaluated. In the durability test, orthogonal transmittance CT at a wavelength of 410 nm and a wavelength of 510 nm was measured using UV3100PC manufactured by Shimadzu Corporation, and an average value of 10 measurements was used.

In the durability test, two samples (about 5 cm × 5 cm) having a polarizing plate on a glass and an optical film on the glass side are prepared. In the single plate orthogonal transmittance measurement, the film side of this sample is set facing the light source and measured. Two samples were measured, and the average value was defined as the single plate orthogonal transmittance.

The single plate orthogonal transmittance was measured in the same manner for each of the sample after standing for 800 hours in an environment of 60 ° C. and relative humidity of 95% and after standing for 50 hours at 105 ° C. without humidity control. The change of the single plate orthogonal transmittance before and after the aging was determined, and this was evaluated as the durability of the polarizer. The relative humidity in an environment without humidity control was in the range of 0% to 20%.

Here, the amount of change in the single plate orthogonal transmittance is a value obtained by subtracting the measured value before the test from the measured value after the test, and is calculated by the following equation.
Amount of change in single plate orthogonal transmittance (%) = (Single plate orthogonal transmittance after durability test (%)-Single plate orthogonal transmittance before durability test (%)

The criteria for evaluating the durability of the polarizer are as follows.
<Evaluation criteria>
○: The change (%) in the transmittance of the orthogonal single plate when the polarizing plate is left in a high temperature and high humidity (60 ° C., relative humidity 95%) environment for 800 hours is 0.65% or less, and the high temperature and low humidity ( 105 ° C., no humidity control) The change in orthogonal transmittance when it is allowed to stand for 50 hours in an environment is 0.05% or less.
X: The amount of change (%) in the crossed single plate transmittance when the polarizing plate was left in a high temperature and high humidity (60 ° C., relative humidity 95%) environment for 800 hours was 0.65% or more, and high temperature and low humidity ( 105 ° C., no humidity control) The change in the orthogonal transmittance when left in an environment for 50 hours is 0.05% or more, which is a practically problematic level.

(4. Evaluation of curing unevenness of packed layer)
Regarding the curing unevenness of the packed bed, the infrared absorption spectrum of the packed bed surface was measured using FT / IR-4100, ATR PRO410-S manufactured by JASCO Corporation, and the curing rate of the filler was determined. Based on the evaluation. More specifically, it is as follows.

First, in the urethane acrylate-based curable resin (before curing), in the infrared absorption spectrum obtained by infrared spectroscopy, a peak due to an acrylic double bond is obtained in the vicinity of a wave number of 810 cm ^−1. To do. This is the initial peak intensity.

Next, after applying a curable resin for forming a filling layer on the hard coat layer side of the optical film produced and curing it by ultraviolet irradiation, infrared absorption spectrum measurement was performed in the same manner as described above, and the above-mentioned 810 cm ^{− was} measured. Measure the intensity of the peak due to the acrylic double bond near ¹ . In the urethane acrylate-based curable resin, the acrylic double bond decreases due to the curing reaction by ultraviolet irradiation, and accordingly, the peak intensity due to the acrylic double bond near 810 cm ⁻¹ also decreases. Therefore, the cure rate of the curable resin can be obtained by calculating the amount of change in peak intensity before and after curing. The curing rate of the curable resin is the ratio of the reacted polymerizable group to the sum of the number of reacted polymerizable groups and the number of unreacted polymerizable groups among the polymerizable groups present in the curable resin. Corresponds to the ratio of numbers.

Here, 10 sheets were prepared by applying a curable resin to the hard coat layer side of the A4 size optical film and curing the resin, and the infrared absorption spectrum was measured at the center of each of the 10 sheets. The curing unevenness of the filled layer was evaluated according to the following criteria at the minimum value of the curing rate.
<Evaluation criteria>
A: The curing rate of the space filler is 65% or more.
A: The curing rate of the void filler is 60% or more and less than 65%.
○: The curing rate of the void filler is 50% or more and less than 60%.
X: The curing rate of the void filler is less than 50%.

(5. Visibility evaluation of image display device)
The liquid crystal display device produced using the optical film of each Example and each comparative example was displayed in black, and the visibility when observed from the front was evaluated based on the following criteria.
<Evaluation criteria>
A: Display unevenness due to uneven curing of the packed layer is not recognized at all.
A: Display unevenness due to uneven curing of the packed layer is hardly observed.
○: Display unevenness due to uneven curing of the packed layer is slightly observed, but there is no problem in actual use.
X: Display unevenness caused by uneven curing of the packed layer is considerably recognized, and there is a problem in practical use.

Tables 1 to 4 show the results of the evaluation of each item described above.

From Table 1, it can be seen that when the cellulose ester film (film substrate) contains a hindered amine compound, the light-resistant adhesion is improved (see Examples 1 to 4 and Comparative Example 2). Among these, in the comparative example 2, the hardening nonuniformity of the filling layer arises, and the display nonuniformity resulting from it arises. This is because in Comparative Example 2, the surface free energy of the hard coat layer is 20 mN / m, which is less than 30 mN / m, and the degree of hydrophilization is weak, so that the hindered amine compound diffused from the cellulose ester film is hard coat layer. It is thought that it was not able to be trapped by and was diffused to the packed bed.

In contrast, in Examples 1 to 4, the surface free energy of the hard coat layer is 30 mN / m or more, and the hindered amine compound is sufficiently hydrophilic to capture the hindered amine compound by the hard coat layer. It is considered that the diffusion to the filling layer is suppressed, and as a result, the curing unevenness and display unevenness of the filling layer are suppressed. In particular, in Examples 2 to 4, since the surface free energy of the hard coat layer is 40 mN / m or more and the surface of the hard coat layer is reliably hydrophilized, the diffusion of the hindered amine compound into the packed layer is suppressed. Thus, it can be said that the effect of suppressing unevenness of curing and display unevenness of the packed layer is high.

Further, from Table 2, the cellulose ester film (film substrate) contains a polymer containing a repeating unit derived from the monomer represented by the general formula (P), whereby the durability of the polarizer is improved. (See Examples 5 to 8 and Comparative Example 4). Among these, in the comparative example 4, the curing unevenness of the filling layer is generated, and the display unevenness resulting therefrom is generated. This is because, as in Comparative Example 2, the surface free energy of the hard coat layer was as low as 20 mN / m, so that the polymer contained in the cellulose ester film was diffused to the packed layer without being trapped by the hard coat layer. it is conceivable that.

On the other hand, in Examples 5 to 8, the surface free energy of the hard coat layer is 30 mN / m or more, and the polymer is sufficiently hydrophilic to trap the polymer with the hard coat layer. It is considered that the diffusion to the filling layer is suppressed, and as a result, the curing unevenness and display unevenness of the filling layer are suppressed. In particular, in Examples 6 to 8, since the surface free energy of the hard coat layer is 40 mN / m or more and the surface of the hard coat layer is reliably hydrophilized, the diffusion of the polymer into the packed layer is suppressed. Thus, it can be said that the effect of suppressing unevenness of curing and display unevenness of the packed layer is high.

Further, from the results of Examples 1 to 4 and 5 to 8, by setting the surface free energy of the hard coat layer to 30 mN / m or more, the effect of capturing the compound diffused from the cellulose ester film by the hard coat layer is It can be said that the case where the compound is the polymer is higher than the case where the compound is a hindered amine compound.

Table 3 also shows that the durability of the polarizer is improved when the cellulose ester film (film substrate) contains the organic acid represented by the general formula (Q) (Examples 9 to 12). , See Comparative Example 6). Among these, in the comparative example 6, the hardening nonuniformity of the filling layer arises, and the display nonuniformity resulting from it arises. This is because, as in Comparative Example 2, the surface free energy of the hard coat layer was as low as 20 mN / m, so that the organic acid contained in the cellulose ester film was diffused to the packed layer without being trapped by the hard coat layer. it is conceivable that.

On the other hand, in Examples 9 to 12, the surface free energy of the hard coat layer is 30 mN / m or more, and the organic acid is sufficiently hydrophilic to trap the organic acid in the hard coat layer. It is considered that the diffusion to the filling layer is suppressed, and as a result, the curing unevenness and display unevenness of the filling layer are suppressed. In particular, in Examples 10 to 12, since the surface free energy of the hard coat layer is 40 mN / m or more and the surface of the hard coat layer is reliably hydrophilized, the diffusion of the organic acid into the packed layer is suppressed. Thus, it can be said that the effect of suppressing unevenness of curing and display unevenness of the packed layer is high.

Further, from the results of Examples 1 to 4 and 9 to 12, the effect of capturing the compound diffused from the cellulose ester film by the hard coat layer by setting the surface free energy of the hard coat layer to 30 mN / m or more is It can be said that the case where the compound is the organic acid is higher than the case where the compound is a hindered amine compound.

Table 4 also shows that the durability of the polarizer is improved when the cellulose ester film (film substrate) contains the compound represented by the general formula (S) (Examples 13 to 16, comparison). (See Example 8). Among these, in the comparative example 8, the hardening nonuniformity of the filling layer arises, and the display nonuniformity resulting from it arises. This is because, as in Comparative Example 2, the surface free energy of the hard coat layer is as low as 20 mN / m, so that the compound contained in the cellulose ester film was diffused to the packed layer without being trapped by the hard coat layer. Conceivable.

On the other hand, in Examples 13 to 16, the surface free energy of the hard coat layer is 30 mN / m or more, and the compound is sufficiently hydrophilic to trap the compound in the hard coat layer. It is considered that diffusion to the layer is suppressed, and as a result, uneven curing and display unevenness of the filled layer are suppressed. In particular, in Examples 14 to 16, since the surface free energy of the hard coat layer is 40 mN / m or more and the surface of the hard coat layer is reliably hydrophilized, it is possible to suppress diffusion of the above compound into the filling layer. It can be said that the effect of suppressing unevenness of curing and display unevenness of the packed layer is high.

Further, from the results of Examples 1 to 4 and 13 to 16, by setting the surface free energy of the hard coat layer to 30 mN / m or more, the effect of capturing the compound diffused from the cellulose ester film by the hard coat layer is It can be said that the case where the compound is a compound represented by the general formula (S) is higher than the case where the compound is a hindered amine compound.

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

1. An optical film having a hard coat layer on at least one surface of a film substrate,
The film substrate includes a hindered amine compound, a polymer containing a repeating unit derived from a monomer represented by the following general formula (P), an organic acid represented by the following general formula (Q), and the following general formula (S). Containing at least one of the compounds represented by:
The optical film, wherein the hard coat layer has a surface free energy of 30 mN / m or more after alkali treatment;

2. 2. The optical film as described in 1 above, wherein the hard coat layer has a surface free energy of 30 mN / m or more after alkali treatment under the following alkali treatment conditions;
[Alkali treatment conditions]
Alkaline solution: 2 mol / L sodium hydroxide solution Treatment temperature: 50 ° C
Processing time: 120 seconds.

3. 3. The optical film as described in 2 above, wherein the hard coat layer has a surface free energy of 40 mN / m or more after alkali treatment under the alkali treatment conditions.

4. 4. The optical film as described in any one of 1 to 3 above, wherein the hard coat layer contains polymer silane coupling agent-coated fine particles.

5. Any one of 1 to 4 above, wherein the concentration of the polymer silane coupling agent-coated fine particles on the surface of the hard coat layer is larger than the concentration of the polymer silane coupling agent-coated fine particles on the entire hard coat layer. The optical film as described.

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

7. 7. A polarizing plate, wherein the optical film according to any one of 1 to 6 is bonded to one surface of a polarizer.

8. 8. An image display device, wherein the polarizing plate according to 7 is provided on at least one surface side of the display cell.

9. The polarizing plate is provided on the viewing side with respect to the display cell, and the optical film is provided on the viewing side with respect to the polarizer,
9. The image display device according to 8 above, wherein a protective part is provided on the hard coat layer of the optical film of the polarizing plate via a filler.

10. A step of alkali-treating the optical film according to any one of 1 to 6;
And a step of bonding the optical film to the polarizer so that the cellulose ester film of the optical film is on the polarizer side after the alkali treatment. .

11. A step of alkali-treating the optical film according to any one of 1 to 6;
After the alkali treatment, forming the polarizing plate by bonding the optical film to the polarizer so that the cellulose ester film of the optical film is on the polarizer side;
Bonding the polarizing plate to a display cell;
Forming a protective part on the hard coat layer in the optical film of the polarizing plate via a photocurable resin;
And a step of forming a filling layer by irradiating an active energy ray to cure the photocurable resin.

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

DESCRIPTION OF SYMBOLS 1 Image display apparatus 3 Protection part 4 Liquid crystal cell (display cell)
5 Polarizing plate 11 Polarizer 12 Film substrate 13 Hard coat layer 15 Optical film 31 Filling layer

Claims

An optical film having a hard coat layer on at least one surface of a film substrate,
The film substrate includes a hindered amine compound, a polymer containing a repeating unit derived from a monomer represented by the following general formula (P), an organic acid represented by the following general formula (Q), and the following general formula (S). Containing at least one of the compounds represented by:
The optical film, wherein the hard coat layer has a surface free energy of 30 mN / m or more after alkali treatment;

(In the general formula (P), R 1 represents a hydrogen atom or an aliphatic group having 1 to 4 carbon atoms. R 2 represents a substituent. (A) is necessary for forming a 5- or 6-membered ring. Represents an atomic group, and n represents an integer of 0 to 4.)

(In general formula (Q), R 26 represents an aryl group, and R 27 and R 28 each independently represents a hydrogen atom, an alkyl group, or an aryl group.)

(In the general formula (S), R 1 represents a hydrogen atom or a substituent, R 2 represents a substituent represented by the following general formula (a). N1 represents an integer of 0 to 4, and n1 is 2 In the above, a plurality of R 1 may be the same or different from each other, n2 represents an integer of 1 to 5, and when n2 is 2 or more, a plurality of R 2 may be the same or different from each other May be.)

(In the general formula (a), A represents a substituted or unsubstituted aromatic ring, and R 3 and R 4 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or the following general formula (b R 5 represents a single bond or an alkylene group having 1 to 5 carbon atoms, X represents a substituted or unsubstituted aromatic ring, and n3 represents an integer of 0 to 10 And when n3 is 2 or more, the plurality of R 5 and X may be the same or different.

(In the general formula (b), X represents a substituted or unsubstituted aromatic ring, and R 6 , R 7 , R 8 , and R 9 are each independently a hydrogen atom or an alkyl having 1 to 5 carbon atoms. N5 represents an integer of 1 to 11, and when n5 is 2 or more, a plurality of R 6 , R 7 , R 8 and X may be the same or different.
It is.
The optical film according to claim 1, wherein the hard coat layer has a surface free energy of 30 mN / m or more after alkali treatment under the following alkali treatment conditions.
[Alkali treatment conditions]
Alkaline solution: 2 mol / L sodium hydroxide solution Treatment temperature: 50 ° C
Processing time: 120 seconds.
3. The optical film according to claim 2, wherein the hard coat layer has a surface free energy of 40 mN / m or more after the alkali treatment under the alkali treatment conditions.
4. The optical film according to claim 1, wherein the hard coat layer contains fine particles coated with a polymer silane coupling agent.
The concentration of the polymer silane coupling agent-coated fine particles on the surface of the hard coat layer is higher than the concentration of the polymer silane coupling agent-coated fine particles on the entire hard coat layer. The optical film described in 1.
The optical film according to claim 1, wherein the film substrate is a cellulose ester film.
A polarizing plate, wherein the optical film according to any one of claims 1 to 6 is bonded to one surface of a polarizer.
An image display device, wherein the polarizing plate according to claim 7 is provided on at least one surface side of the display cell.
The polarizing plate is provided on the viewing side with respect to the display cell, and the optical film is provided on the viewing side with respect to the polarizer,
The image display device according to claim 8, wherein a protective part is provided on the hard coat layer of the optical film of the polarizing plate via a filler.
A step of alkali-treating the optical film according to claim 1;
And a step of bonding the optical film to the polarizer so that the cellulose ester film of the optical film is on the polarizer side after the alkali treatment. .
A step of alkali-treating the optical film according to claim 1;
After the alkali treatment, forming the polarizing plate by bonding the optical film to the polarizer so that the cellulose ester film of the optical film is on the polarizer side;
Bonding the polarizing plate to a display cell;
Forming a protective part on the hard coat layer in the optical film of the polarizing plate via a photocurable resin;
And a step of forming a filling layer by irradiating an active energy ray to cure the photocurable resin.