JP6164050B2 - Optical film, polarizing plate, manufacturing method thereof, and image display device - Google Patents

Description

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

  In recent years, for example, a liquid crystal display device as shown in FIG. 1 is known as an image display device having a protection unit.

  The liquid crystal display device 101 has a transparent protective part 103 made of, for example, glass or plastic on a liquid crystal display panel 102. In this case, in order to protect the polarizing plate 1000 disposed on the outermost surface of the liquid crystal display panel 102, a gap 90 is provided between the liquid crystal display panel 102 and the protection unit 103 by interposing a spacer 90 between the protection unit 103. Is provided. However, the presence of the gap 105 between the liquid crystal display panel 102 and the protective portion 103 causes light scattering, resulting in a decrease in contrast and brightness, and the presence of the gap 105 hinders thinning of the panel. Yes.

  In view of such a problem, it is known to fill a space between a polarizing plate disposed on the outermost surface of a liquid crystal display panel and a protective portion with a photocurable resin.

  On the other hand, the outermost film of the polarizing plate is generally provided with an optical film having a hard coat layer for preventing damage to the polarizing plate. From the viewpoint of productivity, the hard coat layer is generally formed by coating using various coating methods. Additives such as surfactants and leveling agents are generally added to the hard coat layer formed by coating in order to control the wettability with the base film from the uniformity and coatability of the coating film. The

  Additives such as surfactants and leveling agents reduce the surface free energy of the hard coat layer coating component and control wettability to the film substrate.

  In addition, additives such as surfactants and leveling agents have the property of being easily surface oriented in the hard coat layer. By adding a surfactant or leveling agent, the coating film uniformity and coating properties of the hard coat layer are excellent, while the surface free energy of the hard coat layer is reduced, and the photocurable resin that is the above-mentioned void filler and A difference from the surface free energy of the hard coat layer was generated, and the photocurable resin as the void filler was not uniformly applied, resulting in poor appearance such as repellency, and the quality deterioration as an image display device was remarkable.

  A technique for improving this problem is disclosed in Patent Document 1, for example. The technique described in Patent Document 1 is a technique for improving the coating property of the void filler by controlling the viscosity of the void filler and the silicon atom ratio on the surface of the optical film to a specific range. However, in the technique described in Patent Document 1, only limited void fillers can be used, and there is a problem in productivity. In addition, the technique described in Patent Document 1 improves the coating properties of the gap filler, but the improvement in the adhesion between the optical film and the gap filler is not improved, and in particular, long-term use of the image display device is assumed. After the endurance test, the deterioration of adhesion was remarkable.

JP2013-101274A

  Accordingly, it is an object of the present invention to provide an optical film that can uniformly apply a void filler to an optical film and that has improved adhesion after a durability test assuming long-term use of an image display device.

  1. An optical film having a functional layer on at least one surface on a film substrate, wherein the functional layer has a surface free energy of 40 mN / m or more.

2. The functional layer is alkali-treated at least under the alkali treatment conditions shown below, and the difference (θ _Δ ) in water contact angle before and after the alkali treatment is 10 ° or more. Optical film.
Alkaline treatment conditions Alkaline solution: 2 mol / L sodium hydroxide solution Treatment temperature: 50 ° C
Processing time: 120 seconds

  3. The optical film as described in 2 above, wherein the contact angle with water of the functional layer decreases after the treatment under the alkali treatment conditions.

  4. The optical film as described in any one of 1 to 3 above, wherein the functional layer contains a polybasic acidic acrylate compound.

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

  6. The functional layer contains polymer silane coupling agent-coated fine particles and actinic radiation curable resin, and the mass ratio of the polymer silane coupling agent-coated fine particles and the actinic radiation curable resin is a polymer silane coupling agent-coated fine particle. : Actinic radiation curable resin = 0.1: 100 to 10: 100 The optical film as described in any one of 1 to 5 above, wherein:

  7. The optical film as described in any one of 1 to 6 above, wherein the film substrate is a λ / 4 film.

  8. A polarizing plate using the optical film according to any one of 1 to 7 on one surface.

  9. An image display device comprising the polarizing plate according to 8 above in at least one of the liquid crystal cells.

  According to the present invention, it is possible to provide an optical film that can uniformly apply a void filler to an optical film and that has improved adhesion after a durability test that assumes long-term use of an image display device.

FIG. 1 is a schematic diagram illustrating an example of a configuration of a liquid crystal display device. It is a schematic diagram of the diagonally stretched tenter used for this invention. It is the schematic which shows the track | orbit (rail pattern) of the rail of the tenter used for the manufacturing method of this invention. It is a schematic diagram of the extending | stretching apparatus used in the Example. It is a schematic diagram of the extending | stretching apparatus used in the Example. The schematic diagram of a three-dimensional video display apparatus (system with one polarizing plate of glasses). The schematic diagram of a three-dimensional video display apparatus (system with two polarizing plates of glasses). It is a schematic sectional drawing which shows an example of a structure of an image display apparatus. The schematic diagram which attached the weight to the sample which bonded glass and the optical film through the space | gap filler.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail.

  In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit. First, surface free energy will be described.

(Surface free energy)
The surface free energy of the present invention uses a value calculated by the following method. First, the contact angle (θ) of the functional layer surface of the optical film is allowed to stand for 12 hours at 23 ° C. and 55% under the following three components (pure water, ethylene glycol, diethylene glycol), and then at 23 ° C. and 55% Below, it measures using Kyowa Interface Science Co., Ltd. make and brand name Drop Master DM100. The contact angle of each component is measured 5 times, and the values are averaged. Next, the surface free energy is determined using the following Young-Forks 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 + cosθ) / 2
γ _S d = dispersion force component of surface free energy of solid γ _L d = dispersion force component of surface free energy of liquid γ _S p = polarity component of surface free energy of solid γ _L p = polarity of surface free energy of liquid Force component γ _S h = hydrogen bonding component of surface free energy of solid γ _L h = hydrogen bonding component of surface free energy of solid

  Dispersion force component, polar force component, and hydrogen bond strength component of surface free energy of three components (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.

  As a result of intensive studies by the present inventors, when the surface free energy of the functional layer is 40 mN / m or more, the difference in surface free energy between the curable resin as the void filler and the functional layer is suppressed. Excellent wettability of the filler is ensured, and not only the coating uniformity of the void filler is excellent, but also the interlayer adhesion between the void filler and the functional layer is increased, and good adhesion performance is obtained even after the durability test. I found out that

  A preferable range of the surface energy of the functional layer is 40 mN / m or more and 80 mN / m or less.

Moreover, in order to demonstrate the effect of this invention satisfactorily, it is preferable that the functional layer has a difference (θ _Δ ) in water contact angle before and after the alkali treatment of 10 ° or more. Next, the difference (θ _Δ ) in the water contact angle before and after the alkali treatment will be described.

<Difference in contact angle with water before and after alkali treatment (θ _Δ )>
In the optical film of the present invention, the difference (θ _Δ ) in water contact angle before and after alkali treatment of the functional layer is preferably 10 ° or more from the object effect of the present invention. More preferably, they are 10 degrees or more and 55 degrees or less.

Here, the difference (θ _Δ ) between the water contact angle before and after the alkali treatment is after the alkali treatment at least under the conditions shown below from the water contact angle (θ) of the functional layer before the alkali treatment of the optical film. This is a value obtained by subtracting the water contact angle (θa) of the functional layer in order to obtain the difference in water contact angle before and after the alkali treatment (θ _Δ ).

  The alkali treatment condition is a condition in which the optical film is immersed in a 2 mol / L sodium hydroxide solution at 50 ° C. for 120 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 after standing for 12 hours under the conditions of 23 ° C. and 55% RH.

  Since the functional layer has surface characteristics (wetting properties) that show hydrophilicity after alkali treatment, adhesion at the interface between the curable resin layer, which is a void filler, and the functional layer increases, and the layer after the durability test Good adhesion can be obtained. Moreover, it is a preferable aspect in this invention that a water contact angle falls after alkali treatment.

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

The difference (θ _Δ ) in water contact angle before and after alkali treatment satisfies the above by adjusting the type and amount of additives such as compounds described later and the curing conditions (such as oxygen concentration adjustment) of the functional layer forming method. Can be adjusted.

<Optical film>
(Functional layer)
The functional layer according to the present invention 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, a 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 object effect of the present invention, the functional layer according to the present invention preferably contains a polybasic acidic acrylate. Commercially available polybasic acrylates include dipentaerythritol pentaacrylate succinic acid modification, pentaerythritol triacrylate succinic acid modification, dipentaerythritol pentaacrylate phthalic acid modification, pentaerythritol triacrylate phthalic acid modification, polybasic Examples include acid-modified acrylic oligomers. 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. Moreover, as content, when the resin component which forms a functional layer film | membrane is set to 100, it is preferable to contain 30% or more by mass ratio, More preferably, it is preferable to contain 50% or more.

  Other commercial products of the resin include Adekaoptomer N series, Sun Rad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (Sanyo Chemical Industries ( Co., Ltd.), Aronix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (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.

  You may mix the said active ray curable resin individually or in mixture of 2 or more types.

A monofunctional acrylate may also be used. Monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl Examples 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 to contain polyfunctional acrylate: monofunctional acrylate = 80: 20 to 98: 2 in terms of the mass ratio of polyfunctional acrylate and monofunctional acrylate.

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

  The amount of the photopolymerization initiator is preferably contained in a mass ratio of photopolymerization initiator: active ray 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 derivatives thereof, but are not particularly limited thereto. It is not a thing. Commercially available photopolymerization initiators may be used, and preferred examples include Irgacure 184, Irgacure 907, and Irgacure 651 manufactured by BASF Japan.

(Polymer silane coupling agent coated fine particles)
The functional layer contains fine particles coated with a polymer silane coupling agent (also called polymer silane coupling agent-coated fine particles), so that it exhibits good performance especially for adhesion after a durability test. To preferred. The content is preferably a polymer silane coupling agent-coated fine particle: active ray curable resin = 0.1: 100 to 10: 100, in view of exhibiting excellent adhesion performance even after a more severe durability test. .

  The fine particles coated with the polymer silane coupling agent are not particularly limited as long as they are used in the functional layer, but examples of the fine particles include silica, alumina, zirconia, titanium oxide, antimony pentoxide, Silica is preferred. The silica fine particles may be hollow particles having cavities inside. Moreover, as a commercial item of polymer silane coupling agent covering fine particles, for example, ELCOM V-8804 (manufactured by JGC Catalysts & Chemicals Co., Ltd.) can be used.

(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 polymerizable monomers include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n-propyl, (meth) acrylic acid isopropyl, (meth)- n-butyl, isobutyl (meth) acrylate, (meth) acrylic acid-n-hexyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid-n-heptyl, (meth) acrylic acid-n-octyl, (meta ) -2-ethylhexyl acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, benzyl (meth) acrylate, (Meth) acrylic acid-2-methoxyethyl, (meth) acrylic acid-3-methoxybutyl, (meth) acrylic acid-2- Droxyethyl, 2-hydroxypropyl (meth) acrylate, stearyl (meth) acrylate, glycidyl (meth) acrylate, 2-aminoethyl (meth) acrylate, ethylene oxide adduct of (meth) acrylic acid, (meta ) Trifluoromethylmethyl acrylate, 2-trifluoromethylethyl (meth) acrylate, 2-perfluoroethylethyl (meth) acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate, (Meth) acrylic acid 2-perfluoroethyl, (meth) acrylic acid perfluoromethyl, (meth) acrylic acid diverfluoromethyl methyl, (meth) acrylic acid 2-perfluoromethyl-2-perfluoroethyl methyl, (meth) ) 2-perfluorohexylethyl acrylate, ( And (meth) acrylic acid monomers such as 2-perfluorodecylethyl acrylate and 2-perfluorohexadecylethyl methacrylate; styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and the like Styrene monomers such as salts; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; silicon-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; maleic anhydride, maleic acid, malein Monoalkyl and dialkyl esters of acids; fumaric acid, monoalkyl and dialkyl esters of fumaric acid; maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmale Nitrile group-containing vinyl monomers such as dode, 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, ditrimethylolpropanthate (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- Examples thereof include hexanediol dimethacrylate, perfluorooctylethyl methacrylate, trifluoroethyl methacrylate, urethane acrylate, and the like, and mixtures thereof.

  Polymers (oligomers and prepolymers) of these polymerizable monomers can also be used. 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.
X-R-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, 1 type or 2 or more types of 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-glycidoxy Ethyltrimethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltri Toxisilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β-glycidoxyethoxy) propyltrimethoxysilane, γ- (meth) acrylooxymethyltrimethoxysilane, γ- (meth) acrylooxymethyltriethoxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxy Silane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, 3-ureidoisopropylpropyltriethoxysilane, Perfluorooctylethyltrimethoxy Silane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriisopropoxysilane, trifluoropropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ- Examples include aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and the like, and mixtures thereof.

  A polymer 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 and further 1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer is prepared, and a polymerization initiator is added thereto. Can be obtained by adding 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. The total concentration of the polymerizable monomer and the reactive silane compound at this time is preferably in the range of 1 to 40% by weight, more preferably 2 to 30% by weight as the solid content. Polymerization initiators are azoisobutyl nitrile, lauroyl peroxide, benzoyl peroxide, di-t-butyl peroxide, t-butylperoxy-2-ethylhexinoate, t-butylperoxyisobutyrate, t-butyl. Peroxide polymerization initiators such as peroxypivalate, t-butylperoxybenzoate, t-butylperoxyacetate, 2,2-azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvalero) Nitriles) and azo compounds such as 2,2-azobis (4-methoxy-2,4-dimethylvaleronitrile). The reaction temperature is desirably 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 much time to prepare a polymer silane coupling agent with a large molecular weight. On the other hand, if the reaction temperature is too high, the reaction rate will be too high and the desired molecular weight will be May not be able to 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)
The method for preparing polymer silane coupling-coated fine particles can be prepared by adding a polymer silane coupling agent to an organic solvent dispersion of fine particles and coating the fine particles with the polymer silane coupling agent in the presence of an alkali.

  Organic solvents include alcohols such as methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, isopropyl glycol; 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, alcohol Ketones such as preparative acetate, 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 in the range of 1 to 30% by weight, more preferably 2 to 25% by weight as the solid content.

  An 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 to bond. 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 because 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 may be in the range of 0.001 to 0.2 parts by mass of the fine particles, and further 0.005 to 0.1 parts by mass. preferable.

  Subsequently, 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 diameter of the obtained polymer silane coupling agent-coated fine particles is preferably in the range of 5 to 500 nm, more preferably 10 to 200 nm, from the viewpoint of optical properties when used for an optical film.

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

(Conductive agent)
The functional 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 functional layer may contain a fluorine-siloxane graft compound, a fluorine-based compound, or a compound having an HLB value of 3 to 18 in view of applicability. By adjusting the type and amount of these additives, it is easy to control the new aqueous solution.

  The HLB value is Hydrophile-Lipophile-Balance, 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 examples of the compound having an HLB value of 3 to 18 are listed below, but are not limited thereto. Figures in parentheses indicate HLB values.

  Made by Kao Corporation: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), Emulgen 105 (9.7), Emulgen 106 (10.5), Emulgen 108 (12. 1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2) , Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0), Emulgen 409PV (12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5), Emulgen 707 (12.1), Emulgen 7 9 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4), Emulgen 1135S-70 (17.9), Emulgen 2020G-HA (13.0), Emulgen 2025G (15. 7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), manufactured by Nissin Chemical Industry Co., Ltd .: Surfynol 104E (4), Surfynol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4), Surfinol 104S (4), Surfi Knoll 420 (4), Surfynol 440 (8), Surfynol 46 (13), Surfinol 485 (17), Surfinol SE (6), manufactured by Shin-Etsu Chemical Co., Ltd .: X-22-4272 (7), X-22-6266 (8), KF-351 (12), KF-352 (7), KF-353 (10), KF-354L (16), KF-355A (12), KF-615A (10), KF-945 (4), KF-618 (11), KF -6011 (12), KF-6015 (4), KF-6004 (5). The fluorine-siloxane graft compound refers to a compound of a copolymer obtained by grafting polysiloxane and / or organopolysiloxane containing siloxane and / or organosiloxane alone on at least a fluorine-based resin. Such a fluorine-siloxane graft compound can be prepared by a method as described in Examples described later. Or as a commercial item, Fuji Chemical Industries Ltd. ZX-022H, ZX-007C, ZX-049, ZX-047-D etc. can be mentioned. 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. These components are preferably added in the range of 0.005 parts by mass or more and 5 parts by mass or less with respect to the solid component in the functional layer composition.

(UV absorber)
The functional layer may further contain an ultraviolet absorber described in the cellulose ester film described later. As a structure of the film in the case of containing an ultraviolet absorber, when it is constituted by two or more layers, it is preferable that the functional layer in contact with the cellulose ester film contains an ultraviolet absorber.

  The content of the ultraviolet absorber is preferably a mass ratio, and the ultraviolet absorber: functional layer constituting resin = 0.01: 100 to 10: 100. When two or more layers are provided, the thickness of the functional layer in contact with the cellulose ester film 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 functional layer by applying two or more functional layers on a substrate by wet on wet without passing through a drying step. In order to laminate the second functional layer on the first functional layer without passing through the drying process, the second functional layer is laminated by a wet coater sequentially by using an extrusion coater or by using a slot die having a plurality of slits. Can be done.

(solvent)
The functional layer is a functional layer composition prepared by diluting the components forming the functional layer described above with a solvent that swells or partially dissolves the cellulose ester film, and is applied onto the cellulose film by the following method and dried. It is preferable to provide a hard coat layer by curing.

  As the solvent, ketone (methyl ethyl ketone, acetone, etc.) and / or acetate ester (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohol (ethanol, methanol), propylene glycol monomethyl ether, cyclohexanone, methyl isobutyl ketone, etc. are preferable. The coating amount of the hard coat layer is suitably in the range of 0.1 to 40 μm, preferably in the range of 0.5 to 30 μm, as the wet film thickness. The dry film thickness is in the range of 0.01 to 20 μm, preferably in the range of 0.5 to 10 μm. More preferably, it is the range of 0.5-5 micrometers.

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

(Functional layer forming method)
After application of the functional 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 functional layer having excellent film strength can be obtained.

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

  In general, it is known that the drying process changes from a constant state to a gradually decreasing state when drying starts. The decreasing section is called the 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.

The irradiation conditions vary depending on individual lamps, irradiation of actinic rays is generally within the range of 50~1000mJ / 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 functional layer surface, and as a result, it is easy to control _θΔ within the above range. When irradiating actinic radiation, it is preferably performed while applying tension in the film transport direction, and 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.

  The optical film may be surface-modified on the functional layer. 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 characteristics>
(Surface shape)
The arithmetic average roughness Ra (JIS B0601: 2001) of the functional 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 0.1 to 10% from the visibility when used in an image display device. Haze can be measured according to JIS-K7105 and JIS K7136.

(hardness)
As for the optical film of this invention, the pencil hardness which is a parameter | index of hardness has preferable HB or more. If it is more than HB, it is hard 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 weight of 500 g. It is the value measured according to the pencil hardness evaluation method prescribed | regulated by JISK5400.

<Film base>
Next, the film substrate according to the present invention will be described. It is preferable that the film substrate is easy to manufacture, has good adhesion to the functional layer, is optically isotropic, and is transparent.

  Although it will not specifically limit if it has said property, For example, cellulose ester-type films, such as a cellulose diacetate film, a cellulose triacetate film, a cellulose acetate propionate film, a cellulose acetate butyrate film, a polyester-type film, a 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 fill (Arton (manufactured by JSR), ZEONEX, ZEONOR (manufactured by Nippon Zeon)), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film, fluororesin film, nylon film, polymethylmethacrylate A film, an acrylic film, a polylactic acid film, a glass plate, etc. can be mentioned. Among these, a cellulose ester film, a polycarbonate film, and a cycloolefin polymer film are 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 commercially available cellulose ester films include Konica Minoltak KC8UX, KC4UX, KC8UY, KC4UY, KC6UA, KC4UA, KC2UA, KC4UE and KC4UZ (manufactured by Konica Minolta Opto, Inc.). The refractive index of the cellulose ester film is preferably 1.45 to 1.55. The refractive index can be measured according to JIS K7142-2008.

(Cellulose ester resin)
The cellulose ester resin (hereinafter also referred to as cellulose ester or cellulose resin) is preferably a lower fatty acid ester of cellulose. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, etc. Further, mixed fatty acid esters such as cellulose acetate butyrate can be used.

  Among the above descriptions, the lower fatty acid esters of cellulose that are particularly preferably used 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%. Examples of 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.

  Cellulose triacetate has 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 having a substitution degree of 2.75 to 2.90, a number average molecular weight (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 It is preferable to contain.

  Cellulose acetate propionate has an acyl group having 2 to 4 carbon atoms as a substituent. 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 preferred.

Formula (I) 2.6 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5

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

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

  The number average molecular weight (Mn) and molecular weight distribution (Mw) of the cellulose ester can be measured using high performance liquid chromatography. The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G
(Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Mw = 100000 to 500 samples were used. The 13 samples are preferably used at approximately equal intervals.

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

  Acrylic resin also includes methacrylic resin. Although it does not restrict | limit especially as an acrylic resin, What consists of 50-99 mass% of methyl methacrylate units and 1-50 mass% of other monomer units copolymerizable with this is preferable. Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. 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, Maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride and the like may be mentioned, and these may be used alone or in combination of two or more.

  Among 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, and methyl acrylate and n -Butyl acrylate is particularly preferably used. Moreover, it is preferable that a weight average molecular weight (Mw) is 80000-500000, More preferably, it exists in the range of 110000-500000.

  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. The use of a λ / 4 film as the film substrate is preferable from the viewpoint of excellent visibility and crosstalk when the optical film of the present invention is incorporated into an image display device.

  A λ / 4 film refers to a film having an in-plane retardation of the film of about ¼ for a predetermined wavelength of light (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) among the refractive indices at 23 ° C. RH and wavelength of 550 nm, and the slow phase in the film plane. It is the refractive index in the direction perpendicular to the 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).

  Further, in order to function effectively as a λ / 4 film, it is preferable to satisfy the relationship of Ro (590) −Ro (450) ≧ 2 nm at the same time, and Ro (590) −Ro (450) ≧ 5 nm. It is more preferable that Ro (590) -Ro (450) ≧ 10 nm.

  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 slow axis in the plane of the λ / 4 film and the transmission axis of the polarizer is preferably 41 ° to 49 °, more preferably 42 to 48 °, and 43 ° to 47 °. It is still more preferable that it is 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.

  As retardation adjustment of (lambda) / 4, you may add the following retardation regulators to the resin film mentioned above.

(Retardation adjuster)
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 heterocyclic ring in addition to the 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.

  A polycarbonate resin can also be used as the λ / 4 film.

(Polycarbonate resin)
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 a polystyrene resin, a methyl methacrylate resin, and a 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 resin preferably has a glass transition point (Tg) of 110 ° C. or higher and a water absorption rate (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.

  As the λ / 4 film, an alicyclic olefin polymer resin can also be used.

(Alicyclic olefin polymer resin)
Examples of alicyclic olefin polymer resins 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 No. 124244 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 is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in 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 olefin polymer resins 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 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 brought 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 take-up 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. .

  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)
The film substrate according to the present invention has, for example, acrylic particles, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, and hydrated calcium silicate in order to improve handleability. 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 cellulose ester film can be reduced. The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably in the range of 5 to 16 nm, and particularly preferably in the range of 5 to 12 nm.

  It is preferable that the film base material which concerns on this invention 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), as the alkylene glycol component having 2 to 12 carbon atoms, 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, -Hexanediol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, etc., and these glycols are one kind or two kinds or more Used as a mixture. In particular, an alkylene glycol having 2 to 12 carbon atoms is 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, tripropylene glycol, and the like. These glycols are one kind or two or more kinds. 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. Although the specific example (compound X-1-compound X-17) of a compound represented by general formula (X) below is shown, it is not limited to this.

  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, Examples include 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- 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 invention 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.

（式中、Ｒ_１〜Ｒ_８は、水素原子、置換若しくは無置換の炭素数２〜２２のアルキルカルボニル基、或いは、置換又は無置換の炭素数２〜２２のアリールカルボニル基を表し、Ｒ_１〜Ｒ_８は、同じであっても、異なっていてもよい。）

(Wherein R _{1 to} R ₈ represent a hydrogen atom, a substituted or unsubstituted alkyl carbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted aryl carbonyl group having 2 to 22 carbon atoms; R ₁ to R ₈ may be the same or different.)

Although the compound shown with general formula (Y) below is shown more concretely (compound Y-1-compound Y-23), it is not limited to these. In the following table, when the average degree of substitution is less than 8.0, any one of R _{1 to} R ₈ represents a hydrogen atom.

  The substitution degree distribution can be adjusted to the desired substitution degree by adjusting the esterification reaction time or mixing compounds having 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, and more preferably 5 to 20% by mass. It is particularly preferred that

(Other additives)
[Plasticizer]
The film substrate according to the present invention may contain a plasticizer as necessary. 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 point which can control a cellulose-ester film to the retardation value mentioned later.

  The polyhydric alcohol ester plasticizer is a plasticizer comprising 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. Preferably it is a 2-20 valent aliphatic polyhydric alcohol ester. 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 polyvalent carboxylic acid ester plasticizer is a compound composed of an ester of a divalent or higher, preferably 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-mentioned monomers, but the acrylic acid methyl ester monomer unit preferably has 30% by mass or more, and the methacrylic acid methyl ester monomer unit has 40% by mass or more. preferable. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.

  In addition, when making the film base material which concerns on this invention contain the plasticizer mentioned above, it is preferable to make the usage-amount contain 1-50 mass% with respect to a cellulose acetate, and to contain 5-35 mass% more. Preferably, 5 to 25% by mass is contained.

(UV absorber)
The film substrate according to the present invention 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, etc. 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.

  Preferred ultraviolet absorbers are benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers, and particularly preferred are benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers.

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

  As a 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 a triazine type ultraviolet absorber, TINUVIN 400 (2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl)-manufactured by BASF Japan Ltd., which is a commercial product, is available. 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.

  0.5-10 mass% is preferable with respect to a cellulose acetate film, and, as for the usage-amount of a ultraviolet absorber, 0.6-4 mass% is still more preferable.

(Antioxidant)
The film substrate according to the present invention 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-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl). -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-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate Etc. The addition amount of these compounds is preferably 1 ppm to 10000 ppm, more preferably 10 to 1000 ppm in terms of mass ratio with respect to the cellulose acetate film.

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

  Moreover, even when it cannot be visually confirmed, when a functional layer is formed, a coating film cannot 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 substrate 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 substrate is preferably in the range of 0 to 5 nm and the retardation value Rth in the thickness direction is in the range of −10 to 10 nm. 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 cellulose ester film plane, ny is the refractive index in the direction perpendicular to the slow axis in the film substrate plane, and nz is the refractive index in the thickness direction of the cellulose ester film. The rate and d each represent the thickness (nm) of the cellulose ester film.)

  The retardation can be determined at a wavelength of 590 nm in 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 a film base material is demonstrated, it is not limited to this. As a method for producing a cellulose ester film, production methods 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 and the like can be used.

(Organic solvent)
The organic solvent useful for forming a resin solution (dope composition) when a cellulose ester film is produced by a solution casting method is limited as long as it dissolves a cellulose ester resin and other additives at the same time. Can be used without any problem. For example, as the chlorinated organic solvent, methylene chloride, as the 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. Years, 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 a 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 cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferred because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate.

  The 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 perform drying efficiently 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 mass%, Most preferably, it is 20-30 mass% or 70-120 mass%. The amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M 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, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, particularly preferably. It is 0-0.01 mass% or less.

  In the film drying step, 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 width direction (TD direction) of the film. The draw ratios in the biaxial directions perpendicular to each other are preferably 1.0 to 2.0 times in the MD direction and 1.05 to 2.0 times in the TD direction, respectively. It is preferably performed in a 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.

  These width maintenance or width direction stretching in the film forming step is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

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

  The temperature during stretching 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 and kneaded using a single-screw or twin-screw extruder, and formed into a strand from a die. It can be done by extrusion, water cooling or air cooling and cutting.

  The 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.

  A film is formed 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 or twin screw extruder, the pellets are melted at a temperature of about 200 to 300 ° C., filtered through a leaf disk type filter or the like to remove foreign matter, and then formed into a film from a 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 into the extruder from the supply hopper, it is preferable to prevent oxidative decomposition or 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.

  When the cellulose ester film is nipped by the cooling roller and the elastic touch roller, the temperature of the cellulose ester film on the touch roller side 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 rotary member. 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 a stretching method, a known roller stretching machine, a tenter or the like can be preferably used. The stretching temperature is preferably carried out in the temperature range of Tg to (Tg + 60) ° C. of the resin that usually constitutes the film.

  Prior to winding, the ends may be slit and cut to the width of the product, and knurling (embossing) may be applied to both ends to prevent sticking or 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. Since the cellulose ester film is deformed and cannot be used as a product, the clip holding portions at both ends of the film are usually cut out and reused.

<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, the well-known film mentioned above is used for the unstretched film before diagonal stretching.

  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 (orientation angle θ) formed by the extension direction of the film and the slow axis 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)
An obliquely stretched film can be produced using an obliquely stretching apparatus (obliquely stretched tenter). Diagonally stretched tenters can set the orientation angle of the film freely by changing the rail pattern in various ways, and can evenly orient the orientation axis of the film across the width direction of the film with high precision. And the apparatus which can control film thickness and retardation with high precision can be used preferably. Next, a specific method for producing an obliquely stretched film will be described with reference to the drawings.

  FIG. 2 is a schematic view of a tenter capable of oblique stretching used in the method for producing an obliquely stretched film. However, this is an example, and the present invention is not limited to this.

  The unstretched film 1 whose direction is controlled by the guide roll 8-1 on the tenter entrance side is held by the gripping tool (the clip gripping portion) at the positions of the right film holding start point 2-1 and the left film holding start point 2-2. The film is conveyed and stretched by the tenter 4 in the oblique direction indicated by the locus 3-1 of the right film holding means and the locus 3-2 of the left film holding means, and the right film holding end point 5- 1. Grasping is released by the film holding end point 5-2 on the left side, and conveyance is controlled by the guide roll 8-2 on the tenter outlet side, so that the obliquely stretched film 6 is formed. In the figure, the unstretched film is obliquely stretched at an angle (orientation angle θ) in the film stretching direction 9 with respect to the film feeding direction 7-1.

  The distances X1 and X2 between the main shaft position of the guide roll 8-1 closest to the entrance portion of the obliquely stretched tenter and the gripping tool at the entrance portion of the obliquely stretched tenter are preferably 20 to 100 cm, and by maintaining this distance When the film is gripped, the plane of the film can be maintained, and optical characteristics such as the orientation angle θ in the longitudinal direction and retardation can be stabilized. Preferably it is 20-60 cm, More preferably, it is 20-40 cm. Here, X1 is the distance between the main shaft position of the guide roll 8-1 and the gripping tool (clip gripping portion) at the film holding start point 2-1 on the right side, and X2 is the main shaft position of the guide roll 8-1. This is the distance of the gripping tool (clip gripping portion) at the film holding start point 2-2 on the left side.

  X1 and X2 may be either X1 = X2 or X1 ≠ X2, but preferably X1 = X2. In the present invention, both X1 and X2 are preferably within the range of 20 to 100 cm.

  When the distance between the main shaft position of the guide roll 8-1 closest to the entrance of the obliquely stretched tenter and the gripping tool at the entrance of the obliquely stretched tenter is within 100 cm, the uniformity of the Martens hardness of the obliquely stretched film is improved. .

  In order to set the distance between the main shaft position of the guide roll 8-1 closest to the entrance of the obliquely stretched tenter and the gripping tool of the obliquely stretched tenter to the above range, a mechanism capable of adjusting the position of the guide roll and the clip gripping part; The length of the gripping tool in the conveying direction is 1 to 5 inches (1 inch is 2.54 cm), and the diameter of the guide roll 8-1 closest to the entrance portion of the obliquely stretched tenter is 1 to 20 cm. And a mechanism that can further install a roll in the vicinity of the entrance of the obliquely stretched tenter.

  The obliquely stretched film of the present invention is preferably produced using the above-mentioned tenter that can be obliquely stretched. It is a device that widens in an oblique direction with respect to the point movement direction. The tenter includes an oven, a pair of rails on the left and right on which a gripping tool for transporting the film travels, and a number of gripping tools that travel on the rails. Both ends of the film fed out from the film roll and sequentially supplied to the entrance portion of the tenter are gripped by a gripping tool, the film is guided into the oven, and the film is released from the gripping tool at the exit portion of the tenter. The film released from the gripping tool is wound around the core. Each of the pair of rails has an endless continuous track, and the gripping tool which has released the grip of the film at the exit portion of the tenter travels outside and is sequentially returned to the entrance portion.

  The rail shape of the tenter is asymmetrical on the left and right according to the orientation angle θ, the draw ratio, etc. given to the stretched film to be manufactured, and can be finely adjusted manually or automatically. The thermoplastic resin film is stretched, and the orientation angle θ can be set to an arbitrary angle within the range of 10 ° to 80 ° with respect to the winding direction after stretching. In the present invention, the gripping tool of the tenter is configured to travel at a constant speed with a certain distance from the front and rear gripping tools.

  The traveling speed of the gripping tool can be selected as appropriate, but is usually 10 to 100 m / min. The difference in travel speed between the pair of left and right grippers 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 between the left and right sides 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 right and left gripping tools is required to be substantially the same speed. Because. 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 invention.

  In addition, in the oblique stretching tenter, it is preferable that the position of each rail part and the rail connecting part can be freely set. Therefore, when an arbitrary entrance width and exit width are set, the stretching ratio according to this can be set (described below) 3 is an example of a connecting part.

  In the obliquely stretched tenter used in the present invention, a large bending rate is often required for the rail that regulates the trajectory of the gripping tool. 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 an arc at the bent portion.

  FIG. 3 shows the track (rail pattern) of the rail of the tenter. The traveling direction DR1 at the tenter inlet of the unstretched film is different from the traveling direction DR2 at the tenter outlet side of the stretched film, and thus, even in a stretched film having a relatively large orientation angle θ, it is wide and uniform. Optical characteristics can be obtained. The feeding angle θi is an angle formed by the traveling direction D1 at the tenter entrance and the traveling direction DR2 on the tenter exit side of the stretched film. In the present invention, in order to produce a film having an orientation angle θ of preferably 10 ° to 80 ° as described above, the feeding angle θi is 10 ° <θi <60 °, preferably 15 ° <θi <50 °. Set by. By setting the feeding angle θi in the above range, the variation in optical characteristics in the width direction of the obtained film becomes good (smaller).

  The long film is sequentially gripped at both ends (both sides) by the left and right grippers at the tenter entrance (position a), and travels as the grippers travel. The left and right grips CL, CR facing the direction of the film travel (DR1) at the tenter entrance (position a) run on the left-right asymmetric rail, preheating zone, stretching Pass through an oven with zones and cooling zones. Here, “substantially perpendicular” indicates that the angle formed by the straight line connecting the aforementioned gripping tools CL and CR and the film feeding direction DR1 is within 90 ± 1 °.

  In the film after stretching of the obliquely stretched film, a method of adjusting the film temperature during oblique stretching in the stretching zone to have a gradient in the width direction, or the preheating temperature in the preheating zone or the holding temperature in the stretching zone is in the width direction. It is preferable to take a method of adjusting the gradient so that the elastic modulus of the film can be easily controlled.

  The preheating zone refers to a section in which the vehicle travels while maintaining a constant interval between the gripping tools gripping both ends at the oven entrance. The stretching zone refers to an interval until the gap between the gripping tools gripping both ends starts to become constant again. In addition, the cooling zone refers to a section in which the temperature in the zone is set to be equal to or lower than the glass transition temperature Tg of the thermoplastic resin constituting the film in a period in which the interval between the gripping tools after the stretching zone is constant again.

  The temperature of each zone is set to Tg to Tg + 30 ° C., the temperature of the stretching zone is set to Tg to Tg + 30 ° C., and the temperature of the cooling zone is set to Tg−30 ° C. to Tg with respect to the glass transition temperature Tg of the thermoplastic resin. It is preferable to do.

  In order to make the film temperature have a gradient in the width direction, a method of adjusting the opening degree of the nozzle for sending warm air into the temperature-controlled room in the preheating zone or the stretching zone so as to make a difference in the width direction, A known method such as controlling the heating by arranging the heaters in the width direction can be used.

  The gradient in the width direction of the film temperature during oblique stretching in the stretching zone is preferably 0.5 ° C to 10.0 ° C, more preferably 1.0 ° C to 5.0 ° C, and most preferably 1.5 ° C. ~ 3.0. When the temperature is lower than 0.5 ° C, the effect of the temperature gradient is small, and the effect of uniforming the Martens hardness in the film width direction cannot be obtained. When the temperature is higher than 10.0 ° C, Ro is uniform in the film width direction. Cannot be obtained.

  The gradient of the preheating temperature in the preheating zone or the holding temperature in the stretching zone in the width direction is preferably 0.5 ° C. to 10.0 ° C., more preferably 1.0 ° C. to 5.0 ° C., most preferably 1. It is 5 degreeC-3.0.

  The manufacturing pattern of the oblique stretching is shown in FIGS.

  In the drawing, a film feeding device 10, a transport direction changing device 11, a winding device 12, and a film forming device 13 are shown.

  The film feeding device 10 is slidable and pivotable so that the film can be fed at a predetermined angle with respect to the obliquely stretched tenter entrance, or the film feeding device 10 is slidable, and the transport direction changing device 11, it is preferable that the film can be sent out to the entrance of the obliquely stretched tenter. By configuring the film feeding device and the transport direction changing device as described above, it becomes possible to further narrow the width of the entire manufacturing apparatus, and to finely control the film feeding position and angle, It is possible to obtain an obliquely stretched film having small variations in film thickness and optical value and excellent uniformity in elastic modulus of the film. Further, by making the film feeding device and the transport direction changing device movable, it is possible to effectively prevent the left and right clips from being caught in the film.

  By forming the winding device 12 so that the film can be pulled at a predetermined angle with respect to the outlet of the obliquely stretched tenter, it is possible to finely control the film take-up position and angle, and there are variations in film thickness and optical value. It is possible to obtain a diagonally stretched film that is small and excellent in the uniformity of the elastic modulus of the film. Therefore, the generation of wrinkles in the film can be effectively prevented, and the winding property of the film is improved, so that the film can be wound up in a long length. The drawing tension T (N / m) of the stretched film needs to be 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 easily generated, and the retardation and the profile in the width direction of the orientation axis are deteriorated. On the other hand, when the take-up tension is 300 N / m or more, the variation in the orientation angle in the width direction is deteriorated, and the width yield (taking efficiency in the width direction) is deteriorated.

  It is necessary 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, variations in the optical characteristics in the width direction and the flow direction, and nonuniformity in the elastic modulus of the film increase. As a method for controlling the fluctuation of the take-up tension T within the above range, general PID control is performed so that the load applied to the first roll at the tenter outlet, that is, the film tension is measured and the value is kept constant. A method of controlling the rotation speed of the take-up roll by a method is mentioned. Examples of the method for measuring the load include a method in which a load cell is attached to a bearing portion of a roll and a load applied to the roll, that is, a film tension is measured. As the load cell, a known tensile type or compression type can be used.

  The stretched film is released from the tenter outlet after being gripped by the gripper, trimmed at both ends (both sides) of the film, and then wound around a winding core (winding roll) to wind the stretched film. It can be turned around.

  Moreover, you may trim the both ends of the film currently hold | gripped with the holding tool of a tenter before winding up to a winding roll as needed. In addition, before winding, for the purpose of preventing blocking between the films, the masking film may be overlapped and wound up at the same time, or at least one of the stretched films, preferably wound up with tape or the like attached to both ends. Also good. The masking film is not particularly limited as long as it can protect the film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.

  In the obliquely stretched film, the orientation angle θ is inclined in the range of, for example, 10 ° to 80 ° with respect to the winding direction, and the variation in the in-plane retardation Ro in the width direction is 4 nm in a width of at least 1300 mm. Hereinafter, it is preferable that the variation in the orientation angle θ is 1.0 ° or less.

  The variation of the in-plane retardation Ro of the obliquely stretched film is 4 nm or less, preferably 3 nm or less, at least 1300 mm in the width direction. By setting the variation of the in-plane retardation Ro within the above range, the display quality can be improved when used as a retardation film for a liquid crystal display device.

  The variation in the orientation angle θ of the obliquely stretched film is 1.0 ° or less, preferably 0.80 ° or less, at least 1300 mm in the width direction. When a stretched film having a variation in the orientation angle θ exceeding 1.0 ° is bonded to a polarizing plate to obtain a circularly polarizing plate, and this is installed in a liquid crystal display device, light leakage may occur and the contrast may be lowered.

  The optimum value of the in-plane retardation Ro of the obliquely stretched film is selected depending on the design of the display device used. Note that Ro is a value obtained by multiplying the difference between the refractive index nx in the in-plane slow axis direction and the refractive index ny in the direction perpendicular to the slow axis by the average thickness d of the film (Ro = (nx −ny) × d).

  The average thickness of the obliquely stretched film is preferably 20 to 80 μm from the viewpoint of mechanical strength and the like. Moreover, since the thickness unevenness in the width direction affects the uniformity of the film elastic modulus and the possibility of winding, the thickness is preferably 3 μm or less.

(Physical properties of film substrate)
As for the film thickness of a film base material, 5-200 micrometers is preferable, More preferably, it is 5-80 micrometers. Moreover, 500-10000m is preferable and, as for the length of a film base material, More preferably, it is 1000-8000m. By setting it as the range of the said length, it is excellent in the processability in application | coating of a functional layer etc., and the handleability of film base itself.

  Moreover, arithmetic mean roughness Ra of a film base material becomes like this. Preferably it is 2-10 nm, More preferably, it is 2-5 nm. The arithmetic average roughness Ra can be measured according to JIS B0601: 1994.

<Other layers>
The optical film of the present invention can be provided with other layers such as an antireflection layer and a conductive layer.

<Antireflection layer>
The optical film according to the present invention can be used as an antireflection film having an external light antireflection function by coating an antireflection layer on a functional 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 a wavelength of 550 nm.

  The film thickness of the low refractive index layer is preferably in the range of 5 nm to 0.5 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.

General formula (OSi-1): Si (OR) ₄
In the organic silicon compound represented by the general formula, R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

  In addition, a silane coupling agent, a curing agent, a surfactant and the like may be added as necessary. Moreover, you may contain the compound which has a thermosetting and / or photocuring property which mainly contains the fluorine atom which contains a fluorine atom in 35-80 mass%, and contains a crosslinkable or polymeric functional group. Specifically, a fluorine-containing polymer or a fluorine-containing sol-gel compound is used. As the fluorine-containing polymer, for example, a hydrofluorinated monomer in addition to a hydrolyzate or dehydration condensate of a perfluoroalkyl group-containing silane compound [for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane] 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. as needed.

(High refractive index layer)
The refractive index of the high refractive index layer is preferably adjusted to a refractive index in the 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. The means for adjusting the refractive index can be achieved by adding metal oxide fine particles and the like. Metal oxide 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 functional 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 the hard coat film by vacuum deposition, sputtering, ion plating, solution coating, 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 of indium oxide, tin oxide, and indium tin oxide, which can be 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.

<Polarizing plate>
A polarizing plate using the optical film of the present invention will be described. The polarizing plate can be produced by a general method.

  For example, the optical film of the present invention is subjected to alkali saponification treatment, and the treated optical film is bonded to at least one surface of a polarizing film produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Is preferred.

  The other surface may use the optical film or a film substrate such as the cellulose ester film described above. The thickness of the film substrate used for 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. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are those in which iodine is dyed on a system film and those in which dichroic dye is dyed, but it is not limited to this.

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

  On the surface of the polarizing film, one side of the optical film according to the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like. Moreover, a circularly-polarizing plate can also be used as a polarizing plate.

(Circularly polarizing plate)
As a circularly polarizing plate, a 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 polarizer 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 film thickness of the polarizer is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

  The polarizing plate can be produced by a general method. The λ / 4 film subjected to the alkali saponification treatment is preferably bonded 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)
The pressure-sensitive adhesive layer used on one side of the film to be bonded to the substrate of the liquid crystal cell is preferably optically transparent and exhibits moderate viscoelasticity and 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 invention is preferable at the point by which 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 drive systems such as a TN type, STN type, OCB type, VA type, IPS type, ECB type, etc., a touch panel display device And organic EL display devices and plasma displays. Among these image display devices, a liquid crystal display device is preferable because of its high visibility.

  A polarizing plate composed of an optical film having a λ / 4 plate function is preferable from the viewpoint of excellent visibility in a stereoscopic image display device and excellent crosstalk when the head is tilted during image viewing. As the stereoscopic image display device, for example, a stereoscopic image display device including a liquid crystal display device and liquid crystal shutter glasses, the liquid crystal shutter glasses include (1) a polarizing plate (λ / 4 plate), a liquid crystal cell, and a polarizer. Are provided in this order (FIG. 6), or (2) a polarizing plate (λ / 4 plate), a polarizer, a liquid crystal cell, and a polarizer are provided in this order (FIG. 7).

  Next, an example of the configuration of the image display device according to the present invention in which a void filler (photocurable resin) and an optical film are bonded together is shown.

  FIG. 8 shows an example of the configuration of the image display apparatus. FIG. 8 is a schematic cross-sectional view of an example of the configuration of the image display device of the present invention. As shown in FIG. 8, the image display device 200 includes a display panel 210, a polarizing plate 100 including the optical film of the present invention that is configured as a part of the display panel 210, and a front plate 220. A polarizing plate 100 including the optical film 100 is disposed on the viewing side surface of the image display device main body 210. The functional layer surface of the optical film of the polarizing plate 100 including the optical film and the front plate 220 are bonded to each other through a gap filler (photo-curing resin) 230. The front plate is not particularly limited, and a conventionally known one such as an acrylic plate or a glass plate can be used. The material, thickness, etc. of the front plate can be appropriately selected according to the use of the image display device. As the void filler, a solvent-free void 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, cooperative) Chemical Industry Co., Ltd.). One type of void filler may be used alone, or a plurality of types may be used in combination.

  For example, the optical film and the front plate can be bonded together as follows.

  First, a void filler is prepared. A void filler is applied to the surface of the functional layer of the optical film, and a front plate is overlaid on the void filler coating. In this state, the optical film and the front plate are bonded to each other by photocuring the gap filler. When applying the void filler to the functional layer surface, the surface free energy of the functional layer surface is set to 40 mN / m or more so that the void filler is not repelled and the void filler is uniformly spread. An image display device that is maintained and has excellent visibility can be obtained. Furthermore, excellent adhesion can be maintained even after a durability test assuming long-term use.

  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]
(Preparation of cellulose ester film 1)
Preparation of silicon dioxide dispersion Aerosil R812 (Nippon Aerosil Co., Ltd.) 10 parts by mass (average diameter of primary particles 7 nm)
90 parts by mass of ethanol

  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. It filtered with the fine particle dispersion | distribution dilution liquid 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 = 14000) 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 (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

  The above was put into an airtight container, heated, stirred and completely dissolved, and Azumi Filter Paper No. 24 was used to prepare a dope (dope composition 1).

  Next, the belt casting apparatus was used to uniformly cast on a stainless steel band support. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100%, 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 of MD direction computed from the rotational speed of a stainless steel band support body and the driving speed of a tenter was 1.01 times.

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

<< Functional Layer Composition 1 >>
<Composition of functional 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 raw 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.)
Single-end radical 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)
In a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet, 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 solution 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. Moreover, the mass% of the fluorine-siloxane graft compound was calculated | required by HPLC (liquid chromatography).

[Preparation of optical film 2]
An optical film 2 was prepared in the same manner except that the optical layer 1 was changed to the functional layer composition 2 described below.

<< Functional Layer Composition 2 >>
<Composition of functional 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 Irgacure 184 (manufactured by BASF Japan) 6 parts by mass (additive)
KF-642 (polyether-modified silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd.) 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 optical film 3]
An optical film 3 was prepared in the same manner except that the optical layer 1 was changed to the functional layer composition 3 described below.

<< Functional Layer Composition 3 >>
<Composition of functional layer composition 3>
(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)
Surfynol 104E (acetylene dialcohol, manufactured by Nissin Chemical Industry Co., Ltd.) 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 optical film 4]
An optical film 4 was prepared in the same manner except that the optical layer 1 was changed to the functional layer composition 4 described below.

<< Functional Layer Composition 4 >>
<Composition of functional layer composition 4>
(Actinic radiation curable resin)
Polybasic acidic acrylate (Aronix M-510, manufactured by Toagosei Co., Ltd.)
100 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan) 6 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 optical film 5]
An optical film 5 was prepared in the same manner except that the optical layer 1 was changed to the functional layer composition 5 described below.

<< Functional Layer Composition 5 >>
<Composition of functional layer composition 5>
(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)
Polymer silane coupling agent-coated silica (1) 3 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 polymer silane coupling agent coated fine particles>
In a container, 30 ml of methyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd .: Light Ester M), 1 ml of 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-803), 100 ml of tetrahydrofuran as a solvent, azo as a polymerization initiator After adding 50 mg of isobutyronitrile (manufactured by Kanto Chemical Co., Inc .: AIBN) and replacing with N ₂ gas, the mixture was heated at 80 ° C. for 3 hours to prepare a polymer silane coupling agent. The obtained polymer silane coupling agent had a molecular weight of 16,000. The molecular weight was measured with a gel permeation chromatography apparatus. Next, silica sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: Si-45P, SiO ₂ concentration 30% by weight, average particle size 45 nm, dispersion medium: water) is ion-exchanged with an ion exchange resin, and ultrafiltration membrane method is used. Water was replaced with ethanol to prepare 100 g of an ethanol dispersion of silica fine particles (SiO ₂ concentration of 30% by weight).

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

  Thereafter, silica particles having an average particle diameter of 5 μm are added and stirred for 2 hours to adsorb the unadsorbed polymer silane coupling agent in the solution to the silica particles, and then the polymer silane coupling that has not been adsorbed by centrifugation. Silica particles having an average particle diameter of 5 μm adsorbing the agent were removed. 1000 g of ethanol is added to the silica fine particle dispersion adsorbing the polymer silane coupling agent, and the silica fine particles are precipitated, separated, dried under reduced pressure, and then dried at 25 ° C. for 8 hours to obtain polymer silane coupling silica particles (1) Got.

  The obtained polymer silane coupling agent-coated silica (1) had an average particle size of 57 nm.

  The average particle size was measured with a laser particle size measuring device. Subsequently, the produced polymer silane coupling agent-coated silica (1) and the following compound were stirred and mixed to prepare a functional layer composition 5.

[Preparation of optical film 6]
An optical film 6 was prepared in the same manner except that the functional layer composition 6 described below was changed in the production of the optical film 1 produced above.

<< Functional Layer Composition 6 >>
<Composition of functional layer composition 6>
(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)
MegaFuck F-569 (fluorine-containing / hydrophilic group-containing oligomer, manufactured by DIC Corporation) 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 optical film 7]
An optical film 7 was prepared in the same manner as in the production of the optical film 1 produced above except that the functional layer composition 7 was changed to the following.

<< Functional Layer Composition 7 >>
<Composition of functional layer composition 7>
(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)
TSF4440 (polyether-modified silicone, manufactured by Momentive Japan Co., Ltd.)
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

<Evaluation>
The following evaluation was implemented about the produced said optical films 1-7.

(Alkali treatment)
The produced optical films 1 to 7 were subjected to alkali treatment under the following conditions.

(Alkaline treatment conditions)
Saponification step 2 mol / L-NaOH 50 ° C. 120 seconds Water washing step Water 30 ° C. 60 seconds Neutralization step 10 parts by mass HCl 30 ° C. 45 seconds Water washing step Water 30 ° C. 60 seconds

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

1. Evaluation of applicability of void filler Attached onto the 10 cm * 10 cm glass through the optical adhesive tape on the opposite surface of the functional layers of the optical films 1 to 7 after the alkali treatment produced above.

  Next, HRJ-302 (manufactured by Kyoritsu Chemical Industry Co., Ltd.), which is a void filler, is dropped on the functional layers of the optical films 1 to 7, and the void filler is used at 2500 rpm for 15 sec using a spin coater. The film was coated on the entire surface so that the film thickness of the film became 120 μm.

  Next, a sample in which a black PET film was bonded to the surface on which the optical film of glass on which the optical film coated with the void filler was applied to the functional layer was not bonded, and the back surface was black-processed was prepared.

  Next, the surface of the functional layer coated with the void filler was visually observed in the dark room with a green lamp, and repellency was determined according to the following criteria.

A: There is no occurrence of repellency of the void filler.
○: Slight repellency of the void filler can be seen, but there is no practical problem.
X: Level at which repellency of the void filler occurs and causes a practical problem.

2. Durability adhesion evaluation It affixed on the glass of 10 cm * 10 cm through the adhesive tape for optics on the opposite surface of the functional layer of the optical films 1-7 after the said alkali treatment produced.

  Subsequently, HRJ-302 (made by Kyoritsu Chemical Industry Co., Ltd.), which is a void filler, is dropped on each functional layer of the optical films 1 to 7, and the void filling is performed using a spin coater at 2500 rpm for 15 sec. The coating was applied to the entire surface so that the film thickness of the agent was 120 μm.

  Next, glass was bonded to the surface on which the void filler was applied, and light irradiation was performed at 2 J / cm 2 to bond the glass and the optical film via the void filler.

  A weight (50 g) was attached to a sample in which glass and an optical film were bonded via a gap filler as shown in FIG. 9, and the sample was placed in a 90 ° C. dry thermo machine for 500 hours to perform a durability test. About the sample after a durability test, the shift | offset | difference intensity | strength was evaluated on the following references | standards and durable adhesiveness was evaluated.

Deviation strength (adhesion)
A: Level without any deviation.
○: The level of deviation is within 1 mm and does not cause any practical problems.
X: A level that is larger than 1 mm and causes a practical problem.

3. Measurement of surface free energy of optical film Measure the contact angle of each of pure water, ethylene glycol, and diethylene glycol of optical films 1-7 after alkali treatment 5 times, and calculate the surface free energy from the average using the Young-Forks equation described above. Asked. Table 1 shows the results of the surface free energy obtained. In addition, the pure water contact angle of the optical film 1 was 97 °, ethylene glycol was 74 °, and polyethylene glycol was 51 °.

  The contact angle was determined by allowing the sample to stand for 24 hours in an atmosphere at a temperature of 23 ° C. and a relative humidity of 55%, and then using a contact angle meter (trade name DropMaster, manufactured by Kyowa Interface Science Co., Ltd.) DM100) was used, and 1 μL was measured 1 minute after dropping. The measurement was performed 5 times, and the average value was taken as the contact angle of the sample.

4). Difference in pure water contact angle before and after alkali treatment (θ _Δ ) measurement Pure water contact angle (θ) of each functional layer of optical films 1 to 7 before alkali treatment is measured, and each functional layer after alkali treatment is measured. The pure water contact angle (θa) was subtracted to obtain the difference in water contact angle before and after the alkali treatment (θ _Δ ).

The water contact angle was determined by leaving the sample for 24 hours in an atmosphere at a temperature of 23 ° C. and a relative humidity of 55%, and then using a contact angle meter (trade name, manufactured by Kyowa Interface Science Co., Ltd.) in an atmosphere at a temperature of 23 ° C. and a relative humidity of 55%. Using DropMaster DM100), measurement was performed 1 minute after dropping 1 μL of pure water. In addition, it measured 5 times and made the average value of the measured value the water contact angle. Table 1 shows the difference (θ _Δ ) before and after the alkali treatment.

  As can be seen from the results in Table 1, the optical film of the present invention having a surface free energy of 40 mN / m or more has no occurrence of repellency (poor appearance), has excellent void filler coating properties, and adhesion after a durability test. It can be seen that it has excellent properties and is a film. In particular, it can be seen that the functional layer of the optical film of the present invention has a preferable constitution because it exhibits particularly excellent performance by containing fine particles formed by coating with a polybasic acidic acrylate compound or a polymer silane coupling agent.

[Example 2]
In the production of the optical film 5, the addition amount of the polymer silane coupling agent-coated silica fine particles as the additive was changed as shown in Table 2 with respect to pentaerythritol tri / tetraacrylate as the actinic radiation curable resin. Similarly, optical films 8 to 10 were produced.

Next, the alkali treatment and evaluation were performed in the same manner as in Example 1 except that the durability test time for durability adhesion evaluation was changed to 1000 hours and the difference (θ _Δ ) in pure water contact angle before and after the alkali treatment was not measured. The obtained results are shown in Table 2.

  As can be seen from the results in Table 2, the functional layer contains polymer silane coupling agent-coated fine particles and actinic radiation curable resin, and the mass ratio of polymer silane coupling agent-coated fine particles and actinic radiation curable resin is a polymer silane cup. Ring agent-coated fine particles: Actinic radiation curable resin = 0.1: 100 to 10: 100 It can be seen that this is a preferable configuration because it has particularly excellent adhesion after a durability test.

[Example 3]
(Preparation of polarizing plate 101)
The polarizing plate 101 was produced using the sample 1 which bonded glass and the optical film 1 through the space | gap filler, the cellulose-ester film 1, and a polarizing film.

(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 roller 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 preliminary swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to prepare 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 According to the following steps 1 to 3, a polarizing plate 101 was produced by laminating a polarizing film, a cellulose ester film 1, and a sample 1 obtained by laminating glass and an optical film 1 via a gap filler. .

Process 1: The above-mentioned polarizing film was immersed in the storage tank of the polyvinyl alcohol adhesive agent solution of 2 mass% of solid content for 1-2 seconds.
Step 2: The cellulose ester film 1 was subjected to alkali treatment under the following alkali treatment conditions. Next, in Step 1, the polarizing film was immersed in the polyvinyl alcohol adhesive solution. Excess adhesive adhered to the immersed polarizing film is lightly removed, and the cellulose ester film film 1, sample 1 in which glass and optical film 1 are bonded to each other through a gap filler, the optical film surface, and the polarizing film A laminated polarizing plate 101 was prepared by laminating and arranging the cellulose ester film 1.

(Alkaline treatment conditions)
Saponification step 2 mol / L-NaOH 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 and water washing are carried out in this order. It is then dried at 100 ° C.

  Step 3: The sample prepared in Step 2 was dried in a dryer at a temperature of 100 ° C. for 5 minutes to prepare the polarizing plate 101.

<Production of Polarizing Plates 102 to 107>
Polarizers 102 to 107 were produced in the same manner except that the optical film 1 of Sample 1 was changed to optical films 2 to 7 in the production of the polarizer 101.

<Production of Liquid Crystal Display Device 201>
Of two pairs of polarizing plates installed with a liquid crystal layer sandwiched between 21.5 inch liquid crystal display devices (IPS226V-PN, LG Electronics Japan Co., Ltd.), the polarizing plate on one side on the viewer side is peeled off, The prepared polarizing plate 101 was bonded to a liquid crystal cell glass with an optical adhesive so that the glass / void filler / functional layer side was the viewing side, and a liquid crystal display device 201 was prepared. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be orthogonal to each other.

<Production of liquid crystal display devices 202 to 207>
In the production of the liquid crystal display device 201, the liquid crystal display devices 202 to 207 were produced in the same manner except that the polarizing plate 101 was changed to the polarizing plates 102 to 107, respectively.

<Evaluation>
About the produced liquid crystal display device, visibility was observed from the front by black display, and the following references | standards evaluated.

(Visibility)
A: No unevenness caused by repelling is observed.
○: Slight unevenness due to repelling is observed.
X: Unevenness due to deformation is observed.

  As can be seen from the results in Table 3, it can be seen that the surface free energy is excellent in the visibility of an image display device incorporating a polarizing plate composed of the optical film of the present invention having 40 mN / m or more. In particular, it can be seen that the functional layer of the optical film of the present invention exhibits particularly excellent performance by containing fine particles formed by coating with a polybasic acidic acrylate compound or a polymer silane coupling agent.

[Example 4]
<Preparation of cellulose ester film 2>
(Preparation of polyester A)
In a nitrogen atmosphere, 4.85 g of dimethyl terephthalate, 4.4 g of 1,2-propylene glycol, 6.8 g of p-toluic acid, and 10 mg of tetraisopropyl titanate were mixed and stirred at 140 ° C. for 2 hours. Stirring was carried out at ° C for 16 hours. Next, the temperature was lowered to 170 ° C., and unreacted 1,2-propylene glycol was distilled off under reduced pressure to obtain polyester A.

Acid value: 0.1
Number average molecular weight: 490
Dispersity: 1.4
Component content of molecular weight 300-1800: 90%
Hydroxyl (hydroxyl) value: 0.1
Hydroxyl content: 0.04%
Polyester A has a terminal toluic acid ester because the monocarboxylic acid is used in an amount twice as much as that of the dicarboxylic acid.

<Fine particle dispersion 1>
Fine particles (Aerosil R812 manufactured by Nippon Aerosil Co., Ltd.) 11 parts by mass Ethanol 89 parts by mass

  The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

<Fine particle addition liquid 1>
The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

99 parts by mass of methylene chloride 5 parts by mass of fine particle dispersion 1

  A dope solution having the following composition was prepared. Methylene chloride and ethanol were added to the dissolution tank. Cellulose ester, sugar ester compound, polyester A, TINUVIN 928, and fine particle additive solution 1 were charged into a pressure dissolution tank containing a solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

<Composition of main dope solution>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose ester (cellulose acetate propionate: acetyl group substitution degree 1.5, propionyl group substitution degree 0.9, total substitution degree 2.4, Mn 80000)
100 parts by mass Sugar ester compound (Y-22) 7.0 parts by mass Polyester A 2.5 parts by mass TINUVIN 928 (manufactured by BASF Japan Ltd.) 1.5 parts by mass Fine particle additive 1 1.0 part by mass

  The above was put into a sealed container and dissolved with stirring to prepare a dope solution. Next, an endless belt casting apparatus was used to uniformly cast the dope solution on a stainless steel belt support at a temperature of 33 ° C. and a width of 2000 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

  On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film became 75%, and then peeled off from the stainless steel belt support with a peeling tension of 110 N / m.

  The peeled cellulose ester film was stretched 5% in the width direction using a tenter while applying heat at 160 ° C. At that time, the preheating temperature was given in advance so as to have different distributions in the width direction of the film, so that the residual solvent amount at the start of stretching had different distributions in the width direction. The amount of residual solvent at the start of stretching was 15% by mass at one end and 10% by mass at the other end.

  Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m. A roll-shaped cellulose ester film 2 having a film thickness of 75 μm, a width of 2000 mm, and a length of 5200 m was obtained by applying a knurling process having a width of 10 mm and a height of 5 μm to both ends of the film. When the in-plane retardation was measured by the method described above, Ro was 10 nm, Ro variation was 1 nm, and Rt was 120 nm.

<Preparation of diagonally stretched film 1>
The cellulose ester film 2 is set on the slidable feeding device of the device of FIG. 4A, and the A-1a side is the inner rotation side in the oblique stretching machine in which the rail pattern is set so that the angle θi = 47 °. Was fed as At that time, the distance between the main shaft of the guide roll closest to the inlet of the oblique stretching apparatus and the gripping tool (clip gripping part) of the oblique stretching apparatus was 30 cm. A clip having a length in the conveying direction of 1 inch (1 inch is 2.54 cm) and a guide roll having a diameter of 5 cm were used. Diagonal stretching was performed at a stretching temperature of 175 ° C. and a stretching ratio of 1.5 times with an oblique stretching tenter, and stretching was performed in an oblique direction so that the take-up tension at the tenter outlet was 200 N / m and the orientation angle θ was 45 °. The stretched film was controlled so that the fluctuation in the take-up tension was less than 3% by performing feedback control in which the change in the tension measured with the first roll on the outlet side of the obliquely stretched tenter was reflected in the take-up motor rotation speed. Then, after trimming both ends of the film, change the transport direction with a transport direction change device consisting of an air flow roll, apply a knurling process with a width of 10 mm and a height of 5 μm to both ends of the film, and wind it with a slidable winder, An obliquely stretched film 1 having a thickness of 50 μm, a width of 2000 mm, and a length of 5200 m was obtained. The obtained obliquely stretched film 1 had an in-plane retardation (Ro) of 135 nm, a thickness direction retardation Rt of 140 nm, and an orientation angle (θ) of 45 °.

  The film moving speed during heating and stretching was 20 m / min. The temperature of the preheating zone was 175 ° C., and the temperature of the cooling zone was 160 ° C. When the film was heated and stretched, the so-called “Boeing phenomenon” was eliminated, and stretching was performed with an optimum rail pattern so that the orientation angle was 45 °.

(Preparation of protective film 1)
<Fine particle dispersion 1>
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by mass Ethanol 89 parts by mass

  The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

<Fine particle addition liquid 1>
The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

99 parts by mass of methylene chloride 5 parts by mass of fine particle dispersion 1

  A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate was added to a pressurized dissolution tank containing a solvent while stirring. This was heated and stirred to dissolve completely, and this was dissolved in Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

<Composition of main dope solution>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose acetate with an acetyl group substitution degree of 2.4 (Mn 80000)
100 parts by mass Sugar ester compound (Exemplary compound 1-7) 10 parts by mass Polyester (Aromatic terminal ester exemplary compound 3) 3 parts by mass Ultraviolet absorber (Tinuvin 928 (manufactured by BASF Japan Ltd.))
2 parts by mass Particulate additive solution 1 1 part by mass

  The composition was put into a closed container and dissolved with stirring to prepare a dope solution. Next, an endless belt casting apparatus was used to uniformly cast the dope solution on a stainless steel belt support at a temperature of 33 ° C. and a width of 2000 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

  On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film was 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.

  Thereafter, the film is stretched 1.4 times in the width direction by a tenter set at 170 ° C., then dried by being transported in a drying zone set at 130 ° C. for 30 minutes, trimmed at both ends, A protective film 1 having a thickness of 40 μm having a knurling having a width of 1 cm and a height of 8 μm was prepared in a part, and the film was wound up with a width of 2000 mm and 5000 m. The in-plane retardation value Ro and the thickness direction retardation Rt of the protective film 1 were 50 nm and 130 nm, respectively.

<Preparation of optical film 11>
In the production of the optical film 5, an optical film 11 was produced in the same manner except that the film substrate was changed to the obliquely stretched film 1. The optical film 11 was alkali-treated in the same manner as in Example 1 and the surface free energy was determined in the same manner as in Example 1. The results obtained are shown in Table 4.

<Preparation of polarizing plate>
In the same manner as in Example 1, the protective film 1 is provided on the film base surface (opposite surface of the functional layer), the polarizer, and the back surface side of the optical film 11 in which the glass and the optical film are bonded via the gap filler. In the same manner as in Example 3, the polarizing plates 108 were produced by bonding so that the longitudinal directions were matched.

<Production of liquid crystal display device>
The front plate and the polarizing plate on the front side of the SONY 60-type display BRAVIA LX900 were peeled off, and the polarizing plate 108 prepared above and the polarizing plate 105 prepared in Example 3 were each coated with an optical adhesive. Bonded to the glass surface of the liquid crystal cell.

  In that case, it bonded so that an absorption axis might turn to the same direction as the polarizing plate previously bonded. Subsequently, the visibility (repel appearance evaluation) was evaluated in the same manner as in Example 3. Furthermore, crosstalk was also evaluated under the following conditions. The evaluation results are shown in Table 4.

<Crosstalk evaluation>
(3D glasses)
The optical films 5 and 11 produced above were bonded to the panel side of the Sony 3D glasses TDG-BR100. The produced liquid crystal display device was evaluated for crosstalk when the head was tilted during 3D video viewing.

(Evaluation of crosstalk when tilting the head when viewing 3D images)
Immediately after turning on the backlight of each liquid crystal display device in an environment of 23 ° C. and 55% RH, wearing 3D glasses, with the neck tilted so that the glasses are tilted 85 ° while lying down 3D video was viewed and crosstalk was evaluated according to the following criteria.

A: There is no crosstalk. O: A very weak crosstalk is visible. Δ: A slight crosstalk is visible.
X: Crosstalk is clearly visible.

  As can be seen from the results in Table 4, by using the obliquely stretched λ / 4 film as the film base of the optical film of the present invention, a display device not only excellent in visibility but also excellent in crosstalk characteristics is obtained. You can see that

1000, 2000 Polarizing plate 3000 Liquid crystal cell 90 Spacer 101 Liquid crystal display device 102 Liquid crystal display panel 103 Protection part 105 Gap 1 Unstretched film 2-1 Right film holding start point 2-2 Left film holding start point 3-1 Right side Trajectory of film holding means 3-2 Trajectory of left film holding means 4 Tenter 5-1 Right film holding end point 5-2 Left film holding end point 6 Diagonally stretched film 7-1 Film feed direction 8-1 Tenter Guide roll on the entrance side 8-2 Guide roll on the tenter exit side 9 Film stretching direction DR1 Feeding direction DR2 Winding direction θi Feeding angle (angle formed between the feeding direction and the winding direction)
CR, CL Gripping tool Wo Width of film before stretching W Width of film after stretching A Liquid crystal shutter glasses A1, A4 Polarizer A2 Liquid crystal cell A3 λ / 4 plate B Liquid crystal display device (for example, television (TV))
C Polarizing plate C1 λ / 4 plate C2 Polarizer C3 Optical film C4 Polarizer protective film D Liquid crystal cell E Polarizing plate F Backlight HC Hard coat layer AR Antireflection layer
DESCRIPTION OF SYMBOLS 100 Hard coat film 200 Image display apparatus 210 Image display apparatus main body 220 Front plate 230 Interlayer filler

Claims (10)

In the optical film having a functional layer on at least one surface of the film substrate state, and are surface free energy 40 mN / m or more of said functional layer, and the functional layer of polymeric silane coupling agent-coated particles An optical film characterized by containing . The functional layer contains polymer silane coupling agent-coated fine particles and a resin, and the mass ratio of the polymer silane coupling agent-coated fine particles and the resin is polymer silane coupling agent-coated fine particles: resin = 0.05: 100. The optical film according to claim 1, wherein the optical film is ˜12: 100. The functional layer contains polymer silane coupling agent-coated fine particles and actinic radiation curable resin, and the mass ratio of polymer silane coupling agent-coated fine particles and actinic radiation curable resin is polymer silane coupling agent-coated fine particles: active line curing resin = 0.1: 100 to 10: optical film according to claim 1 or 2, characterized in that there at 100.   The optical film according to claim 1, wherein the functional layer contains a polybasic acidic acrylate compound. The film substrate, the optical film according to any one of claims 1 to 4, characterized in that a lambda / 4 film. It is a manufacturing method of the optical film of any one of Claim 1-5, Comprising: The said functional layer is alkali-treated on the alkali treatment conditions shown below at least, and the water contact angle before and behind alkali treatment is the same. Difference (θ _Δ ) Is 10 ° or more. A method for producing an optical film, wherein
Here, the difference in contact angle with water before and after alkali treatment (θ _Δ ) Is obtained by subtracting the water contact angle (θa) of the functional layer after alkali treatment under the conditions shown below from the water contact angle (θ) of the functional layer before alkali treatment of the optical film. Difference in water contact angle between front and rear (θ _Δ ).
Alkaline treatment conditions
Alkaline solution: 2 mol / L sodium hydroxide solution
Processing temperature: 50 ° C
Processing time: 120 seconds The method for producing an optical film according to claim 6 , wherein a contact angle with water of the functional layer decreases after the treatment under the alkali treatment conditions . A polarizing plate characterized by using a one surface of the optical film of any one of claims 1-5. It is a method of manufacturing the polarizing plate which provided the optical film of any one of Claims 1-5 on one surface, Comprising: The said functional layer of the said optical film is alkali by the alkali treatment conditions shown below at least. Difference in water contact angle before and after alkali treatment (θ _Δ ) Having a step of 10 ° or more.
Here, the difference in contact angle with water before and after alkali treatment (θ _Δ ) Is obtained by subtracting the water contact angle (θa) of the functional layer after alkali treatment under the conditions shown below from the water contact angle (θ) of the functional layer before alkali treatment of the optical film. Difference in water contact angle between front and rear (θ _Δ ).
Alkaline treatment conditions
Alkaline solution: 2 mol / L sodium hydroxide solution
Processing temperature: 50 ° C
Processing time: 120 seconds   An image display device comprising the polarizing plate according to claim 8 in at least one of the liquid crystal cells.

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