WO2006120807A1 - Plaque de polarisation et affichage a cristaux liquides - Google Patents

Plaque de polarisation et affichage a cristaux liquides Download PDF

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Publication number
WO2006120807A1
WO2006120807A1 PCT/JP2006/306085 JP2006306085W WO2006120807A1 WO 2006120807 A1 WO2006120807 A1 WO 2006120807A1 JP 2006306085 W JP2006306085 W JP 2006306085W WO 2006120807 A1 WO2006120807 A1 WO 2006120807A1
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Prior art keywords
film
liquid crystal
polarizing plate
optical film
mass
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PCT/JP2006/306085
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English (en)
Japanese (ja)
Inventor
Nobuo Kubo
Masataka Takimoto
Shinichiro Suzuki
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Konica Minolta Opto, Inc.
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Publication of WO2006120807A1 publication Critical patent/WO2006120807A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers

Definitions

  • the present invention relates to a polarizing plate and a liquid crystal display device, and more particularly to a polarizing plate and a liquid crystal display device having a wide viewing angle and improved brightness unevenness and curl characteristics.
  • Cellulose ester films have been used for polarizing plates and the like as films for protecting polarizers used in liquid crystal displays in recent years because of their high transparency and easy adhesion with polarizers.
  • a polarizing plate protective film is required to have a function of expanding a viewing angle in order to improve the display quality of a liquid crystal display device.
  • a discotic liquid crystal film is required. It is disclosed that the viewing angle characteristics of a liquid crystal cell can be improved by disposing on the top and bottom surfaces of a twisted nematic (TN) type liquid crystal cell.
  • a technique for improving the viewing angle by improving the liquid crystal mode is disclosed in, for example, Patent Document 2, in which a liquid crystal compound is aligned substantially vertically when no voltage is applied, and is aligned substantially horizontally when a voltage is applied.
  • a liquid crystal display device using a vertically aligned (VA) type liquid crystal cell is disclosed.
  • VA type liquid crystal is characterized by its wide viewing angle and high speed response. Nevertheless, it needs to be improved compared to CRT.
  • Patent Document 3 discloses a design value of a retardation film for an MVA liquid crystal display device.
  • the development of liquid crystal display devices equipped with polarizing plates with even better display quality is desired.
  • a liquid crystal display device using a lateral electric field switching mode (hereinafter, sometimes referred to as an IPS mode), which is a display device having excellent viewing angle characteristics, has been proposed.
  • IPS mode lateral electric field switching mode
  • drawbacks such as a decrease in contrast and uneven brightness in the 45 ° direction.
  • display devices using various retardation films have been proposed, but the structure is complicated, there are problems in productivity, and improvements are required.
  • Patent Document 4 discloses that a retardation film is produced by a heat shrink treatment method using a heat shrink film, and that nz> nx ⁇ ny can be realized.
  • Patent Document 5 discloses a method for producing a retardation film including a region of (nx> nz> ny), and this specification also includes a method of heat shrinking in the specification.
  • the film produced by this method is difficult to ensure the uniformity of the retardation and also has poor curl characteristics, and is uniform in a display device using a polarizing plate produced using the film. It was difficult to obtain a good display quality.
  • Patent Document 1 JP-A-7-191217
  • Patent Document 2 JP-A-2-176625
  • Patent Document 3 Japanese Patent Laid-Open No. 2003-262869
  • Patent Document 4 Japanese Patent Laid-Open No. 2002-207123
  • Patent Document 5 Japanese Patent Laid-Open No. 2001-174632
  • an object of the present invention is to provide a polarizing plate and a liquid crystal display device having a wide viewing angle and improved brightness unevenness and curl characteristics.
  • the optical film A is on the side farther from the liquid crystal cell, and the optical film B is on the side closer to the liquid crystal cell.
  • the optical film B contains fine particles B, and the aspect ratio of the primary particles of the fine particles—A is AR (A) and the aspect ratio of the primary particles of the fine particles—B is contained.
  • the aspect ratio AR (A) of the primary particles of the fine particles A is 1 or more and less than 2, and 0.01% by mass or more based on the mass of the thermoplastic resin constituting the optical film A 0 Less than 5% by mass, and the primary particle aspect ratio AR (B) of the fine particles B is 2 or more and 100 or less, and 0.5% by mass with respect to the mass of the thermoplastic resin constituting the optical film B.
  • the polarizing plate according to any one of 1 to 3 above, which is contained in an amount of 30% by mass or less.
  • thermoplastic resin is a cellulose ester-based resin.
  • a liquid crystal display device wherein the polarizing plate according to any one of 1 to 4 is at least one polarizing plate sandwiching a liquid crystal cell.
  • FIG. 1 is a schematic diagram showing a configuration of a MVA mode type liquid crystal display device that is preferable to the present invention!
  • FIG. 2 is a schematic diagram showing the configuration of an IPS liquid crystal display device that is preferable to the present invention.
  • FIG. 3 is a schematic diagram showing directions of an absorption axis Z and a transmission axis of an optical film 2b, a polarizer, and a liquid crystal cell of an IPS liquid crystal display device preferable for the present invention.
  • FIG. 4 is a schematic view showing another combination of the directions of the absorption axis Z and the transmission axis of the optical film 2b, the polarizer, and the liquid crystal cell of the IPS type liquid crystal display device preferable for the present invention.
  • the present invention is a polarizing plate in which optical films are respectively disposed on both sides of a polarizer, the optical film A on the side farther from the liquid crystal cell, the liquid crystal cell closer, and the optical film B on the side.
  • the optical film A contains the fine particles A
  • the optical film B contains the fine particles B
  • the aspect ratio of the primary particles of the fine particles—A is AR (A)
  • the primary particles of the fine particles—B A polarizing plate characterized by AR (A) and AR (B) when the aspect ratio is AR (B) is to improve luminance unevenness and curl characteristics with a wide viewing angle. It is what I found
  • the fine particles-A are matting agents
  • the fine particles-B are acicular birefringent fine particles
  • the optical film B is a retardation film. This is also what we found.
  • the optical film B disposed on the side close to the liquid crystal cell is preferably a retardation film. Birefringence is exhibited by changing the orientation by a stretching operation. It is preferable to contain fine birefringent fine particles.
  • the fine particle-B preferably has a primary particle having a major axis of 10 to 500 nm, and a primary particle aspect ratio AR (B) defined below with a minor axis perpendicular thereto is 2 to : LOO, particularly preferably having an aspect ratio of 3 to 30.
  • birefringent fine particles described in WO01Z025364 or JP-A-2004-109355 can be used.
  • various carbonates such as calcium carbonate, zinc carbonate, manganese carbonate, manganese carbonate, cobalt carbonate, zinc carbonate, barium carbonate, various oxides represented by titanium oxide, MgSO-5Mg (OH)
  • Birefringent needles such as 3H 0, 6CaO-6SiO ⁇ ⁇ 0, 9A1 O -2B O
  • tetragonal, hexagonal and rhombohedral crystals are preferably uniaxial birefringent crystals, orthorhombic crystals, monoclinic crystals and triclinic crystals. These may be single crystals or polycrystals.
  • rod-like or short fiber-like particles of polystyrene or acrylic resin are preferably used.
  • it may be a short fiber-like particle having a polystyrene resin or an acrylic resin, which is produced by cutting an ultrafine fiber with high strength.
  • These fibers are preferably stretched during the production process because they easily develop birefringence.
  • V which is contained in these particles, be cross-linked!
  • the present invention is not limited to these, and various types can be used as long as the above-described requirements such as size, shape, and aspect ratio are satisfied.
  • the aspect ratio is obtained from the absolute maximum length and the diagonal width of the particle by the following equation. This can also determine the image data power obtained by electron microscopic observation of fine particles or fine particles contained in the film.
  • Aspect ratio Absolute maximum length Z diagonal width
  • the diagonal width is when the image of a particle projected by two straight lines parallel to the absolute maximum length is sandwiched Represents the shortest distance between two straight lines.
  • the birefringent fine particles are preferably subjected to a surface treatment with a silane coupling agent, a titanate coupling agent, or the like!
  • the birefringence of the birefringent fine particles is defined as follows.
  • the refractive index for light polarized in the major axis direction of the birefringent fine particle is n (parallel), and the average refractive index for light polarized in the direction perpendicular to the major axis direction is n (vertical).
  • the birefringence ⁇ of the birefringent fine particles is defined by the following equation.
  • the force is preferably 0.01-0.3, preferably 0.05-0.3. I still like the power!
  • Birefringent crystals having positive birefringence include MgSO ⁇ 5Mg (OH) ⁇ 3H 0, 6C
  • crystal examples include calcium carbonate and strontium carbonate.
  • acicular crystals it means a material in which the refractive index in the long direction of the crystal form is smaller than the refractive index in the direction perpendicular thereto.
  • the carbonate fine particles can be produced by a uniform precipitation method or a carbon dioxide gas compound method.
  • the strontium carbonate crystal can be obtained by bringing strontium ions dissolved in water into contact with carbonate ions.
  • Carbonate ions can be obtained by adding carbon dioxide gas to a solution containing a strontium compound by a method such as publishing, or by adding a substance that generates carbonate ions to react or decompose.
  • strontium carbonate crystal fine particles can be produced by the method described in JP-A-2004-35347, and the strontium carbonate fine particles obtained by this method can be preferably used as birefringent fine particles.
  • Urea is an example of a substance that generates carbon dioxide gas. Carbon dioxide gas ions and strontium ions generated in combination can be reacted to obtain strontium carbonate fine particles.
  • fine crystals In order to obtain fine crystals, it is preferable to react at a temperature as low as possible. It is preferable to cool below the freezing point because fine crystal particles can be obtained. For example, it is also preferable to add an organic solvent such as ethylene glycol as a freezing point depressing substance. It is preferable to add so that the freezing point is below 5 ° C below freezing point. As a result, fine particles of strontium carbonate having an average particle size in the major axis direction of 500 nm or less can be obtained.
  • an organic solvent such as ethylene glycol
  • the addition amount of the fine particles B is 0.5 mass% or more and 30 mass% or less with respect to the mass of the thermoplastic resin constituting the optical film B according to the present invention.
  • the range of 0.75 to 19% by mass is more preferable in obtaining the effect and the effect of the present invention.
  • the fine particles B are dispersed in an appropriate dispersion resin and an organic solvent, and the dispersed fine particle B dispersion is used V. It is preferable to produce optical film B using the prepared composition.
  • the fine particle-B-dispersing resin preferably has a weight average molecular weight of 3000-200000, and preferably 3000-90000.
  • the weight average molecular weight is more preferred ⁇ or 5000 to 50000, and more preferably 10000 to 30000! / ⁇ ⁇ ⁇ .
  • the inventors of the present invention prefer the following for the fats and the weight average molecular weights are as described above.
  • the fine particle cocoon-dispersing resin is specifically a single resin having an ethylenically unsaturated monomer unit.
  • Homopolymers or copolymers can be mentioned, more preferably, polymethyl acrylate, polyethyl acrylate, polypropyl acrylate, polycyclohexyl acrylate, alkyl acrylate copolymer, polymethacrylic acid.
  • Acrylic acid or methacrylic acid homopolymer or copolymer such as methyl acid, polyethyl methacrylate, cyclohexyl polymethacrylate, alkyl methacrylate ester copolymer, etc., and acrylic acid or methacrylic acid ester Is excellent in transparency and compatibility, and is preferably a homopolymer or copolymer having an acrylate or methacrylate unit, particularly a homopolymer or copolymer having an acrylic acid or methyl methacrylate unit. . Specifically, methyl polymethacrylate is preferred.
  • An alicyclic alkyl ester of acrylic acid or methacrylic acid such as polyacrylic acid or polymethacrylic acid cyclohexane is preferred because it has advantages such as high heat resistance, low hygroscopicity and low birefringence.
  • the resin examples include cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate and the like having a acyl group substitution degree of 2.0 to 2.8; Cellulose ethers having an alkyl group substitution degree of 2.0 to 2.8, such as etherol, senorelose cetenole ethenole, cellulose propyl ether, etc .; Polyamides of polymers of alkylene dicarboxylic acids and diamines; alkylene dica Polymers of rubonic acid and diol, polymers of alkylene diol and dicarboxylic acid, polymers of cyclohexane dicarboxylic acid and diol, polymers of cyclohexane diol and dicarboxylic acid, aromatic dicarboxylic acid and Polyester resin such as polymer with diol; polyvinyl acetate, vinyl acetate copolymer Vinyl acetate resin; Polyvinyl acetal resin such as polybutacetal,
  • epoxy resin a compound having two or more epoxy groups in one molecule is formed by ring-opening reaction, and the following epoxy resin can be mentioned.
  • Typical commercial products are Alraldide EPN1179 and Alaldide AER260 (Asahi Ciba Co., Ltd.).
  • the alaldite EPN 1179 has a weight average molecular weight of about 405.
  • n represents the degree of polymerization. [0049] [Chemical 1] d V ⁇ -Nd3 6-
  • the ketone resin is obtained by polymerizing vinyl ketones, and examples thereof include the following ketone resins, and typical commercially available products include NO, ILAC 110 and HiLac 110H. (Hitachi Chemical Co., Ltd.). n represents the degree of polymerization.
  • a fine particle dispersion having almost no cohesiveness can be formed by the above-described coagulation and a dispersion method as described below.
  • These coffins are, for example, uniform films with little increase in haze even when they are contained in a dope (cellulose concentration 10 to 30% by mass) which is a high concentration cellulose ester solution used for solution casting. It is a rosin that can form.
  • the concentration of the fine particle B dispersion resin in the fine particle B dispersion is preferably 0.1 to less than 20% by weight.
  • the concentration in the fine particle B dispersion varies depending on the added resin. However, it is preferable to contain 0.2 to 15% by mass.
  • the viscosity of the fine particle-B dispersion in the range of 100 to 500 mPa's.
  • organic solvent an organic solvent useful for forming a dope for dissolving a cellulose ester described later can be preferably used.
  • Dispersers used in preparing the fine particle dispersion as described above of the present invention are roughly classified into a medialess disperser and a metia disperser, and both can be used.
  • a medialess disperser there is a type of menton gorge that disperses using high pressure.
  • Metia dispersers include sand mills and ball mills that disperse using the impact force of media such as glass beads and ceramic beads. Particularly preferred is a medialess disperser that does not contain media debris.
  • the addition method of the fine particles B is not particularly limited, but it may be combined with a matting agent and the like described later. In-line addition is preferable in that it is uniformly dispersed in the film.
  • thermoplastic resin that can be used in the optical films A and B used in the present invention is preferably easy to manufacture, optically uniform, and optically transparent. . Any of these properties can be used.
  • thermoplastic resin for the optical film according to the present invention cellulose ester-based resin, polycarbonate-based resin film, and cycloolefin-based resin are preferred in the present invention, particularly as thermoplastic resin.
  • Cellulose ester-based resin 1S Manufacturing is advantageous in terms of cost, transparency, uniformity, adhesion, and the like.
  • optical films A and B used in the present invention are bonded with a polyvinyl alcohol polarizer and a polybulual alcohol adhesive by an alkali acid treatment which preferably uses a cellulose ester resin.
  • U preferred in terms of matching.
  • thermoplastic resin used in the optical films A and B used in the present invention particularly preferred cellulose esters will be described as the thermoplastic resin used in the optical films A and B used in the present invention.
  • the acyl group when a cellulose ester is used for the thermoplastic resin, the acyl group may be single or different.
  • the degree of substitution can be changed to obtain the desired birefringence.
  • the cellulose ester used in the present invention may be a mixture of a plurality of types of structures having different substitution degrees, or may be a mixture of a plurality of types of structures.
  • the optical film A to be used in the present invention, B is, U,.
  • the cellulose ester that can be used in the optical film used in the present invention is not particularly limited, but the substitution degree and composition of the cellulose ester are important.
  • Cellulose molecules are composed of many glucose units connected, and the glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution. example For example, cellulose triacetate has a acetyl group bonded to all three hydroxyl groups of the glucose unit.
  • the cellulose ester used in the present invention is a carboxylic acid ester having about 2 to 22 carbon atoms, and may be an aromatic carboxylic acid ester, particularly 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.
  • the acyl group bonded to the hydroxyl group may be linear or branched or may form a ring. Further, another substituent may be substituted. When the degree of substitution is the same, birefringence decreases when the number of carbon atoms is large. Therefore, the number of carbon atoms is preferably selected from among 2 to 6 carbon acyl groups.
  • the cell mouth ester preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms.
  • the cellulose ester can use an acyl group derived from a mixed acid, and particularly preferably, an acyl group having 2 and 3 carbon atoms or 2 and 4 carbon atoms can be used.
  • examples of the cellulose ester used in the present invention include cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate to which propiol group or butyryl group is bonded in addition to acetyl group such as cellulose acetate propionate butyrate.
  • Mixed fatty acid esters are particularly preferably used.
  • the petityl group that forms petitate may be linear or branched.
  • cellulose ester preferably used in the present invention cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and cellulose acetate phthalate are particularly preferably used.
  • Preferred cellulose esters for the present invention are those that simultaneously satisfy the following formulas (1) and (2).
  • Equation (1) 4. 4 ⁇ X + Y ⁇ 2.8
  • Formula (2) 0 ⁇ 2.5
  • x is the degree of substitution of the acetyl group
  • ⁇ is the degree of substitution of the propionyl group and Z or butyryl group.
  • cellulose acetate propionate is particularly preferably used, among which 1.5 ⁇ X ⁇ 2.3 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 of the cellulose ester used in the present invention is preferably in the range of 60,000 to 300,000, since the mechanical strength of the resulting film is strong. Further, 70000-200000 are preferably used.
  • the number average molecular weight of the cellulose ester can be measured as follows.
  • the measurement is performed by high performance liquid chromatography under the following conditions.
  • the cellulose used as a raw material for the cellulose ester used in the present invention is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. Moreover, the cellulose ester obtained from them can be mixed and used at an arbitrary ratio.
  • the acylating agent of the cellulose raw material is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride)
  • an organic acid such as acetic acid such as methylene chloride
  • the reaction is performed using an organic solvent and a protic catalyst such as sulfuric acid. Is called.
  • the acylating agent is acid chloride (CH COCl, CH COCl, CH COC1)
  • the reaction is carried out using a basic compound such as amine as a catalyst. Specifically, it can be synthesized with reference to the method described in JP 10-45804.
  • the degree of degradation can be defined by the value of the weight average molecular weight (Mw) Z number average molecular weight (Mn) that is usually used. That is, in the process of cellulose triacetate vinegar, it is too long to decompose too much, and vinegar is used as an index of the reaction level for allowing vinegar to react for a sufficient time V,
  • the weight average molecular weight (Mw) and Z number average molecular weight (Mn) values can be used.
  • An example of a method for producing a cellulose ester is as follows: 100 parts by mass of a cotton-based printer is crushed as a cellulose raw material, 40 parts by mass of acetic acid is added, and pretreatment activation is performed at 36 ° C for 20 minutes. Did. Thereafter, 8 parts by mass of sulfuric acid, 260 parts by mass of acetic anhydride and 350 parts by mass of acetic acid were added, and esterification was performed at 36 ° C for 120 minutes. After neutralization with 11 parts by mass of a 24% magnesium acetate aqueous solution, the mixture was aged for 35 minutes at 63 ° C. to obtain acetyl cellulose.
  • the synthesized cellulose ester is preferably purified to remove low molecular weight components or to remove unacetylated or low vinegar components by filtration.
  • Cellulose esters are also affected by trace metal components in cellulose esters. These are thought to be related to water used in the manufacturing process, but metal ions such as iron, calcium, and magnesium are preferred to contain fewer components that can form insoluble nuclei. Insoluble matter may be formed by salt formation with a polymer degradation product or the like that may be lost, and it is preferable that the amount is small.
  • the iron (Fe) component is preferably 1 ppm or less.
  • the calcium (Ca) component scum derived from insoluble calcium as soon as it forms a coordination compound, that is, a complex with an acidic component such as carboxylic acid or sulfonic acid, and many ligands (insoluble ).
  • the calcium (Ca) component is 60 ppm or less, preferably 0 to 30 ppm.
  • the magnesium (Mg) component too much too much will cause insoluble matter, so 0 to 70 ppm is preferable, and 0 to 20 ppm is particularly preferable.
  • Metal components such as iron (Fe) content, calcium and a) content, and magnesium (Mg) content are pre-treated by microdigest wet cracking equipment (sulfuric acid decomposition) and alkali melting. After the analysis, it can be analyzed using ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer).
  • optical films A and B used in the present invention the following various materials can be used.
  • a plasticizer In the dope or composition for producing the optical film, a plasticizer, an ultraviolet absorber, an antioxidant, a light stabilizer, a dye, a matting agent, a retarder deon adjuster and the like are added.
  • These compounds may be added together with the cellulose ester and the solvent during the preparation of the cellulose ester solution, or may be added during or after the solution preparation.
  • plasticizers except for retardation adjustment agents that improve optical properties, plasticizers, UV absorbers, antioxidants and light stabilizers that provide heat and humidity resistance for liquid crystal display devices are added as heat stabilizers. It is preferable to do.
  • Optical films A and B used in the present invention contain compounds known as plasticizers for the purpose of improving mechanical properties, imparting flexibility, imparting water absorption resistance, reducing water vapor permeability, and adjusting retardation.
  • plasticizers for example, phosphoric acid esters and carboxylic acid esters are preferably used.
  • An acrylic polymer having a hexyl group in the side chain is also preferably used.
  • Examples of the phosphate ester include triphenyl phosphate, tricresyl phosphate, and phenyl diphosphate.
  • Examples of carboxylic acid esters include phthalic acid esters and citrate esters.
  • Examples of phthalic acid esters include dimethyl phthalate, jetyl phthalate, dicyclohexyl phthalate, dioctyl phthalate, and jetyl hexyl phthalate. Examples thereof include acetyl acetyl thioate and acetyl butyl cetate.
  • Alkylphthalylalkyl glycolates are also preferably used for this purpose.
  • the alkyl in the alkylphthalylalkyl glycolate is an alkyl group having 1 to 8 carbon atoms.
  • alkyl phthalyl alkyl glycolate examples include methyl phthalyl methyl acrylate, ethyl phthalyl ethyl acrylate, propyl phthalyl propyl glycolate, butyl phthalyl butyl acrylate, octyl phthalyl octyl acrylate, and methyl phthalyl ethyl acrylate.
  • the amount of the added force of these compounds is preferably 1% by mass to 20% by mass with respect to the cellulose ester from the viewpoints of achieving the desired effect and suppressing the bleeding out of the film force. Also, since the heating temperature during stretching and drying rises to about 200 ° C, the plasticizer preferably has a vapor pressure of 1333 Pa or less at 200 ° C in order to suppress the pre-out.
  • Examples of the ultraviolet absorber used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. A benzotriazole-based compound with little coloring is preferable. Further, UV absorbers described in JP-A-10-182621 and JP-A-8-337574, and polymer UV absorbers described in JP-A-6-148430 are preferably used.
  • an ultraviolet absorber from the viewpoint of preventing deterioration of polarizers and liquid crystals, it has an excellent ability to absorb ultraviolet rays having a wavelength of 370 nm or less, and from the viewpoint of liquid crystal display properties, it absorbs less visible light having a wavelength of 400 nm or more. ! /, I like things! / ...
  • benzophenone compounds include 2,4 dihydroxybenzophenone, 2, 2'-dihydroxy-4-methoxybenzophenone, 2hydroxy-1-methoxy-1-5-sulfobenzophenone, bis (2 methoxy 4 Hydroxy 5 benzoylmethane) and the like, but is not limited thereto.
  • the ultraviolet absorber described above preferably used in the present invention is a benzotriazole ultraviolet absorber or benzophenone ultraviolet absorber excellent in the effect of preventing deterioration of a highly transparent polarizing plate or liquid crystal element.
  • Benzotriazole-based ultraviolet absorbers are particularly preferably used because they have less unwanted coloration that is preferred by the agent.
  • the UV absorber can be added to the dope without limitation as long as the UV absorber dissolves in the dope, but in the present invention, the UV absorber is methylene chloride, Cellulose ester as a UV absorber solution by dissolving in a good solvent for cellulose esters such as methyl acetate and dioxolane, or in a mixed organic solvent of a good solvent and a poor solvent such as a lower aliphatic alcohol (methanol, ethanol, propanol, butanol, etc.) It is preferable to mix with solution to make dope. In this case, it is preferable to make the dope solvent composition and the solvent composition of the UV absorber solution the same or close as possible.
  • the content of the ultraviolet absorber 0.5 the cellulose ester 01% to 5 mass 0/0, in particular 0.5 wt% to 3 wt 0/0.
  • a hindered phenol compound is preferably used, and 2, 6-di-tert-butyl-cresole, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenol) Propionate], Triethylene glycol bis [3 (3-t-butyl-5-methyl-4-hydroxyphenol) propionate], 1, 6 Xanthdiol-bis [3- (3,5-di-t-butyl-4-hydroxyphenol) propionate], 2,4 bis (n-octylthio) -6- (4-hydroxy 3,5 — Butyl-lino) -1, 3, 5 triazine, 2, 2 Thiodiethylenebis [3- (3,5 di-t-butyl 4-hydroxyphenol) propionate], Octadecyl 3- (3, 5-di 1-tert-butyl 4-hydroxyphenol) propionate, N, N 'xamethylenebis (3,5 di-tert-butyl) Propionate, N,
  • 2,6 Di-tert-butyl-cresole, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenol) propionate], triethylene glycol-bis [3- (3-tert-butyl —5-methyl-4-hydroxyphenol) propionate] is preferred.
  • hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-tert-butyl 4-hydroxyphenyl) propiol] hydrazine, tris (2,4- Phosphorous processing stabilizers such as di (tert-butylphenol) phosphite may be used in combination.
  • the amount of addition of these compounds is preferably lppm to 3.0% by weight with respect to the cellulose ester ⁇ ! ⁇ 1.5% is more preferred.
  • examples of the compound used for stabilizing the film constituent material upon heat melting include a hindered amine light stabilizer (HALS) compound, which is a known compound. 2, 2, 6, 6— as described in columns 5-11 of US Pat. No. 4,619,956 and columns 3-5 of US Pat. No. 4,839,405. Tetraalkylbiperidine compounds, acid addition salts thereof or complexes of these with metal compounds are included.
  • HALS hindered amine light stabilizer
  • Tetraalkylbiperidine compounds, acid addition salts thereof or complexes of these with metal compounds are included.
  • Such compounds include those of the following general formula (1).
  • R1 and R2 are H or a substituent.
  • Specific examples of hindered amine light stabilizer compounds include: 4-hydroxy-1,2,2,6,6-tetramethylpiperidine, 1-aryl-1, hydroxyl 2,2,6,6-tetramethylpiperidine, 1-benzyl 4-hydroxy-1,2,2,6,6-tetramethylpiperidine, 1- (4-tert-butyl-2-butyr) mono-4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy 2,2 , 6, 6-Tetramethylbiperidine, 1-ethyl-4-salicyloyloxy 2, 2, 6, 6-tetramethylpiperidine, 4-methacryloyloxy- 1, 2, 2, 6, 6 Pentamethylpiperidine, 1, 2, 2, 6, 6-Pentamethylpiperidine-4-yru j8 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1 Benji
  • the stabilizer is added to the film constituting material can be chosen at least one or more, the amount of added Caro, relative to the weight of the cellulose ester, the addition amount of the stabilizer is 0.001 mass 0/0 More preferably, it is 0.005 mass% or more and 3 mass% or less, More preferably, it is 0.01 mass% or more and 1.5 mass% or less.
  • the addition amount of the stabilizer is less than the range of the above addition amount, the stabilizing effect of the material at the time of heat melting is low, so that the effect of the stabilizer cannot be obtained, and the range of the addition amount is not limited. From the standpoint of compatibility with the resin, the transparency of the retardation film is lowered, and the film may become brittle.
  • an aromatic compound having two or more aromatic rings as described in the specification of European Patent 911 , 656A2 can be used.
  • Aromatic heterocycles that are particularly preferred to be aromatic heterocycles are generally unsaturated heterocycles. Of these, 1,3,5 triazine ring is particularly preferred. Two or more kinds of compounds having a 1, 3, 5 triazine ring may be used in combination. Two or more discotic compounds (for example, a compound having a 1, 3, 5 triazine ring and a compound having a porphyrin skeleton) may be used in combination.
  • Fine particles contained in the optical film A according to the present invention—A has an aspect ratio of primary particles as defined above and is less than 2 and is less than 0.01 mass with respect to the mass of the thermoplastic resin constituting the optical film A. % Or more and less than 0.5% by mass is preferable.
  • the aspect ratio of the primary particles of the fine particles A is AR (A)
  • the aspect ratio of the primary particles of the fine particles B is AR (B)
  • the relationship is AR (A) ⁇ AR (B).
  • the fine particles A are preferably so-called matting agents described below.
  • a matting agent in the film, an effect of facilitating transportation and winding can be expected.
  • the fine particles that are as fine as possible are preferable as the matting agent, for example, sodium nitric acid, titanium dioxide, acidic aluminum, acidic zirconium, calcium carbonate, kaolin, talc, calcined calcium carbonate.
  • inorganic fine particles such as hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate, and crosslinked polymer fine particles.
  • nickel carbonate is preferable because it can reduce the haze of the film.
  • Fine particles such as nickel silicate are often surface-treated with organic substances, but such particles are preferred because they can reduce the haze of the film.
  • Preferred organic materials for the surface treatment include halosilanes, alkoxysilanes, silazanes, siloxanes, and the like.
  • the average particle diameter of the fine particles is larger! /, And the slip effect is larger, and on the contrary, the average particle diameter is smaller!
  • the aspect ratio of the primary particles of Fine Particles-A is 1 or more and less than 2, and the average particle size of preferred primary particles is 5 ⁇ ! ⁇ 50 nm is preferred, more preferably 7 nm to 14 nm.
  • the average particle size of the secondary particles of the fine particles is preferably in the range of 0.05 / ⁇ ⁇ to 1.
  • the amount of the fine particles A added to the optical film A is 0.01 mass% or more and less than 0.5 mass% with respect to the mass of the thermoplastic resin constituting the optical film A. The effects of the present invention can be obtained.
  • silicon dioxide fine particles examples include Aerosil 200, 200V, 300, R972, R972V, R974, R202, R812, 0X50, TT600, etc. manufactured by Nippon Aerosil Co., Ltd. Are Aerogenole 200V, R972, R972V, R974, R202, R812. Two or more of these fine particles may be used in combination. When two or more types are used together, they can be mixed and used at an arbitrary ratio. In this case, fine particles having different average particle sizes and materials, for example, Aerosil 200V and R972V can be used in a mass ratio of 0.1: 99.9 to 99.9: 0.1.
  • thermal stabilizers such as inorganic fine particles such as kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide and alumina, and alkaline earth metal salts such as calcium and magnesium may be added.
  • antistatic agents, flame retardants, lubricants, oils, etc. may be added.
  • the following organic solvents can be used.
  • Organic solvents useful for forming a dope that dissolves cellulose ester include chlorine-based organic solvents and non-chlorine-based organic solvents.
  • chlorinated organic solvents include methylene chloride (salt and methylene), which are suitable for dissolving cellulose esters, especially cellulose triacetate.
  • the use of non-chlorine organic solvents is being studied due to recent environmental problems.
  • Non-chlorine organic solvents include 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—tetrafluoro-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, etc.
  • a dissolution method at room temperature can be used, but an insoluble material can be obtained by using a dissolution method such as a high-temperature dissolution method, a cooling dissolution method, or a high-pressure dissolution method. Can be reduced, which is preferable.
  • a dissolution method such as a high-temperature dissolution method, a cooling dissolution method, or a high-pressure dissolution method. Can be reduced, which is preferable.
  • cellulose esters other than cellulose triacetate methylene chloride can be used, but methyl acetate, ethyl acetate, and acetone are preferably used. In particular, methyl acetate is preferred.
  • an organic solvent having good solubility in the cellulose ester is referred to as a good solvent, and an organic solvent that exhibits a main effect on dissolution is used as a main organic solvent or a main organic solvent.
  • the good solvent in the present invention is a solvent that dissolves 5 g or more of cellulose ester in the solvent lOOg at 25 ° C.
  • the dope used in the present invention preferably contains 1% by mass to 40% by mass of an alcohol having 1 to 4 carbon atoms in addition to the above organic solvent! /. These are used as a gelling solvent that casts the dope onto a metal support and then the solvent begins to evaporate and the ratio of alcohol increases and the web gels, making the web strong and easy to peel off from the metal support. However, when these ratios are small, they also have a role of promoting the dissolution of cellulose esters of non-chlorine organic solvents.
  • Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol. Of these, ethanol is preferred because it has excellent dope stability, has a relatively low boiling point, good drying properties, and no toxicity. These organic solvents fall into the category of poor solvents because they are poorly soluble in cellulose esters.
  • the poor solvent in the present invention is a solvent that dissolves less than 5 g of cellulose ester in 100 g of solvent at 25 ° C.
  • the concentration of the cellulose ester in the dope is adjusted to 15 mass% to 40 mass%, and the dope viscosity is adjusted to the range of 10 Pa's to 50 Pa's. preferable.
  • the optical films A and B according to the present invention may be produced by a deviation method such as a solution casting method (solution casting) or a melt casting method (melt casting).
  • a deviation method such as a solution casting method (solution casting) or a melt casting method (melt casting).
  • solution casting and melt casting are compared, in solution casting, it takes a long time until the dope liquid in which the thermoplastic resin is dissolved in the solvent is discharged by die force and has self-supporting force. Since the viscosity of the dope solution is relatively low, the film can be leveled and a film with high flatness can be obtained. On the other hand, the production speed cannot be improved, and the production method is relatively low in productivity. .
  • thermoplastic resin is obtained by heating and melting thermoplastic resin.
  • melt-formed cellulose ester film is used as a film for optical applications in which the triacetyl cellulose film obtained by the conventional solution casting is used. Nah ...
  • a polarizing plate protective film which is a typical optical film, are colorless and transparent, have uniform planarity, low birefringence, and contact with a polarizer. It is excellent in wearability. Therefore, any material that can satisfy such characteristics can be used as the polymer material constituting the polarizing plate protective film without being limited to triacetyl cellulose that has been used so far.
  • PET which is a general transparent plastic
  • a melt-formed film having excellent flatness is obtained by stretching about 10 times.
  • these films cannot be used as a polarizing plate protective film.
  • Cellulose ester has a low photoelastic coefficient and low birefringence generated by stretching. In this case, the film can be used as a polarizing plate protective film even if stretching is used in order to enhance the flatness.
  • thermoplastic resins that can be formed into a melt, which is difficult to generate birefringence even when stretched, but cycloolefin-based thermoplastic resins are Since it is a very hydrophobic thermoplastic resin, it has poor adhesion to a polarizer formed using a hydrophilic polymer and is difficult to use as a polarizing plate protective film.
  • cellulose ester can hydrophilize the film surface by saponifying the film surface, and can be bonded to the polarizer using an aqueous adhesive. Excellent adhesion to polarizers. If the composition and degree of substitution of the mixed fatty acid ester of cellulose ester is different, the conditions for the hydrophilization treatment may be different. The key time, the pH of the key solution, and the saponification temperature can be changed. Is possible. At this time, the hydrophilic treatment may be performed by a known surface modification such as corona treatment, plasma treatment, or atmospheric pressure plasma treatment.
  • the optical films A and B used in the present invention are preferably cellulose ester films formed by the melt casting method.
  • a preferred example of the melt casting method is a method in which a film-forming material is heated to exhibit its fluidity and then extruded and formed on a drum or an endless belt.
  • optical films A and B used in the present invention are preferably formed by melt casting described below, but are not limited thereto.
  • a molding method by melt casting that melts by heating without using a solvent (for example, methylene chloride, etc.) used in the solution casting method includes a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, It can be classified into blow molding method, stretch molding method and the like.
  • the melt extrusion method is excellent for obtaining a polarizing plate protective film having excellent mechanical strength and surface accuracy.
  • the winding length of the optical film used in the present invention is preferably 500 to 5000 m force, more preferably 1000 to 5000 m force S. Narin is 0-25% of the film thickness at both ends. It is also preferable to roll up with a group.
  • a component that volatilizes at a temperature lower than the melting temperature for film formation is present from the viewpoint of avoiding generation of a volatile component during heating and melting.
  • materials to be added to the optical film used in the present invention it is preferable to use materials whose 1% mass reduction temperature Td (1. 0) is 250 ° C. or more.
  • Volatile components such as moisture and impurities are preferably removed before film formation or before melting.
  • This removal can be performed by a drying method, such as a heating method, a reduced pressure method, or a heated reduced pressure method. Drying may be performed in air or in an atmosphere where an inert gas such as nitrogen or argon is selected as the inert gas.
  • These inert gases preferably have a low water or oxygen content. It is preferable that the oxygen concentration is 0.1% or less, and the dew point of the gas is preferably 30 ° C or less. Most preferably, it does not contain substantially.
  • the moisture or solvent remaining after the removal in the drying step is the mass of the entire film constituent material. The content is preferably 1% by mass or less, more preferably 0.5% by mass or less.
  • the moisture of the cellulose ester ⁇ are those of less than 0.3 mass 0/0 Ru are preferably used. These characteristic values can be measured by ASTM-D817-96.
  • the cellulose ester is preferably used in an amount of 0.1 to 1000 ppm by further reducing the moisture by heat treatment.
  • the amount of residual organic solvent can be measured by a headspace gas chromatography method. That is, a known amount of optical film is heated in a sealed container at 120 ° C. for 20 minutes, and the organic solvent contained in the gas phase in the sealed container is quantified by gas chromatography. From this result, the amount of residual organic solvent (%) can be calculated.
  • the film constituent materials can reduce the generation of volatile components by drying before film formation, and can be reduced by at least one type of resin other than resin, or resin and film constituent materials. It can be divided into a mixture or a compatible material and dried.
  • the drying temperature is 80 ° C. or higher and is not higher than the Tg or melting point of the material to be dried. Including the viewpoint of avoiding fusion between materials, the drying temperature is more preferably 70 to (Tg-5) ° C, and more preferably 80 to (Tg-15) ° C.
  • the preferred drying time is 0.5 to 24 hours, more preferably 1 to 18 hours, and even more preferably 1.5 to 12 hours.
  • the removal rate of volatile components may be low, or drying may take too much time, and when Tg is present in the material to be dried, heating to a drying temperature higher than Tg Materials can be fused and difficult to handle. It is preferable to perform the drying at 1 atm or less. It is particularly preferable to perform the drying while reducing the pressure from vacuum to 1 Z2 atm. Drying is preferably carried out with moderate agitation of materials such as fat, etc.
  • the fluidized bed method in which drying air or dry nitrogen is fed from the bottom in a drying container, is the necessary drying in a shorter time. This is preferable because it can be performed.
  • the drying process may be separated into two or more stages.
  • the material is formed using a material that has been subjected to storage in the preliminary drying process, and dried immediately before film formation to immediately before a week. It's okay.
  • the drying process By the drying process, volatile components such as moisture and impurities in the film-forming material are removed. After that, the film-forming materials are mixed individually or in advance, made into Z pellets, sent to a heated barrel, melted and fluidized, and then extruded into a sheet by a ⁇ die. It is brought into close contact with a cooling drum or an endless belt by a method, etc., and is cooled and solidified to be solidified into a sheet shape to obtain an unstretched sheet. These processes are called casting processes
  • the melting temperature (temperature in the barrel) is preferably in the range of 180 to 270 ° C, more preferably 220 ° C to 250 ° C. .
  • the temperature of the cooling drum is preferably maintained at 90 to 150 ° C. If the drum temperature is 90 ° C or less, the die force is also rapidly cooled, and the structure in the film may become uneven in the film thickness direction or become brittle. The above is preferable. On the other hand, when the temperature is 150 ° C. or higher, the cooling rate of the unstretched sheet is slowed, and the productivity is decreased.
  • the thickness of the protective film is preferably 10 to 500 / ⁇ ⁇ .
  • 10 to: LOO / z m force S is preferable, and 20 to 80 ⁇ m is preferable, and 30 to 60 ⁇ m is particularly preferable.
  • the optical film is thicker than the above region, for example, when used as a polarizing plate protective film, the polarizing plate after polarizing plate processing becomes too thick, and is particularly thin in liquid crystal displays used for notebook computers and mono-type electronic devices. Not suitable for lightweight purposes.
  • the thickness is smaller than the above range, the film has high moisture permeability, and the ability to protect the polarizer against humidity is also undesirable.
  • retardation films it is difficult to express retardation, which is not preferable.
  • the drying load increases remarkably.
  • a drying step is unnecessary, a film having a large film thickness can be produced with high productivity. Therefore, there is an advantage that it is easier than ever to increase the thickness of the film in accordance with the purpose of providing a necessary phase difference or reducing moisture permeability. Further, even when a film is obtained with a thin film thickness, it has an effect that it can be produced with high productivity by stretching such a thick film.
  • the film thickness of the film at the time of drawing becomes thin in inverse proportion to the draw ratio. For example, if the unstretched sheet was 200 When stretched twice, 100 films can be obtained.
  • the film thickness variation of the optical film support is preferably in the range of ⁇ 3%, more preferably ⁇ 1%, and even more preferably 0.1%. These film thickness fluctuations can be reduced by stretching.
  • the width of the polarizing plate protective film is preferably lm or more.
  • the width of the optical film used in the present invention is preferably 1 to 4 m, particularly preferably 1.4 to 2 m. According to the present invention, even a film having a width of 1.4 m or more can be stretched laterally to control the uniform film thickness and the birefringence for the purpose of the present invention.
  • the film discharged from the die and cooled and solidified is disclosed in transverse stretching, longitudinal stretching, or JP-A-2004-226465. It is preferable to perform stretching in the oblique direction. By performing the stretching operation, the birefringence value can be controlled, the flatness can be improved, and the production speed can be improved. These stretching operations may be performed a plurality of times, and may be performed simultaneously or sequentially when performed a plurality of times. When drawing several times, the product of all the draw ratios becomes the final draw ratio. For example, if the 2 times stretching is performed twice, the final stretching ratio will be 4 times.
  • the cellulose ester of the present invention can be processed into a film with higher flatness by stretching, as well as improving the mechanical properties of the film, not only by obtaining a melt-formed film having high flatness even when unstretched. And increase productivity. Therefore, it is possible to produce a high-quality optical film with high productivity.
  • the retardation is determined by the orientation of the thermoplastic resin constituting the film and the fine particles contained therein. This retardation can be controlled by stretching the film.
  • Retardation value in the film plane (hereinafter sometimes referred to as Ro) should be significantly reduced.
  • biaxial stretching is preferred. When biaxial stretching is performed, stretching may be performed simultaneously or sequentially. By stretching at the same magnification in the direction orthogonal to the first stretching axis, the occurrence of birefringence due to the first stretching is canceled, and an optically isotropic film can be obtained.
  • the ratio of the first stretching and the second stretching is changed, and the stretching ratio of either one is changed.
  • An optically anisotropic film can be obtained by stretching so as to be larger than the other stretching ratio.
  • the draw ratio between the width direction and the longitudinal direction is preferably 1.0 to 3.0, more preferably 1.01-2.5.
  • the Tg of the optical film can be controlled by the type of material constituting the film and the ratio of the constituting materials.
  • the Tg when the film is dried is preferably 100 ° C or higher, more preferably 110 ° C or higher. This is because when the optical film used in the present invention is used in a liquid crystal display device, if the Tg of the film is lower than the above, The influence of temperature, humidity, and knocklight heat will affect the orientation of molecules fixed inside the film, increasing the possibility of significant changes in the retardation value and dimensional stability and shape of the film. . In addition, the shape of the film may not be maintained.
  • the glass transition temperature is preferably 200 ° C or lower, more preferably 180 ° C or lower. At this time, it can be obtained by the method described in Tgi of IS K7121.
  • TD stretching it is preferable to perform transverse stretching while sequentially raising the temperature difference in the range of 1 to 50 ° C in a stretching region divided into two or more because the distribution of physical properties in the width direction can be reduced. Furthermore, after transverse stretching, holding the film within the range of Tg—40 ° C or more below the final TD stretching temperature for 0.01 to 5 minutes is preferable because the distribution of physical properties in the width direction can be further reduced.
  • Heat setting is usually performed at a temperature higher than the final TD stretching temperature and within a temperature range of Tg—20 ° C or lower, usually for 0.5 to 300 seconds. At this time, it is preferable to heat-set while sequentially raising the temperature in a range where the temperature difference is 1 to 100 ° C. in the region divided into two or more.
  • the heat-set film is usually cooled to Tg or less, and the clip gripping portions at both ends of the film are cut and wound.
  • a relaxation treatment of 0.1 to 10% in the transverse direction and the Z or longitudinal direction within a temperature range not higher than the final heat setting temperature and not lower than Tg.
  • cooling is performed from the final heat setting temperature to Tg at a cooling rate of 100 ° C or less per second.
  • Means for cooling and relaxation treatment are not particularly limited, and can be performed by conventionally known means. In particular, it is preferable to carry out these treatments while sequentially cooling in a plurality of temperature ranges from the viewpoint of improving the dimensional stability of the film.
  • the cooling rate is a value obtained by (Ti-Tg) Zt, where Tl is the final heat setting temperature and t is the time until the film reaches Tg from the final heat setting temperature.
  • the optical film used in the present invention does not substantially use a solvent in the film forming step, and therefore, the residual organic solvent contained in the optical film wound up after film formation.
  • the amount is stably less than 0.1% by mass, which makes it possible to provide an optical film having more stable flatness and Rth than before. In particular, it is possible to provide an optical film having stable flatness and Rth even for a long roll of 100 m or more. Even if the length of the optical fiber is not limited, the length of 1500 m, 2500 m, or 5000 m is preferably used.
  • the residual organic solvent amount (%) of the cellulose ester film produced by the solution casting method was set to 0.
  • a cellulose ester film having a residual organic solvent content can be obtained at low cost and extremely low cost.
  • a cellulose ester film having excellent properties as an optical film can be obtained.
  • the clip gripping portions at both ends of the cut film are pulverized or granulated as necessary, and then used as film raw materials of the same type. Or you may reuse as a raw material for films of a different kind.
  • the optical film B When used as a retardation film for a VA mode liquid crystal panel (when two films are used on both sides of the liquid crystal panel), the optical film B contains fine birefringent fine particles B, and is a retardation film.
  • the values are preferably 30 ⁇ Ro ⁇ lOOnm and 70 ⁇ Rth ⁇ 400nm, especially 35 ⁇ Ro ⁇ 65nm and 90 ⁇ Rth ⁇ 180nm. If the phase difference is expressed only on the film on one side of the liquid crystal panel, it is preferable to have a phase difference of 40 ⁇ Ro ⁇ lOOnm and 150 ⁇ Rth ⁇ 350nm! /.
  • the retardation value Ro is 1 05nm ⁇ Ro ⁇ 350nm
  • Nz is preferably 0.2 ⁇ Nz ⁇ 0.7
  • Rth is preferably in the range of 30 nm ⁇ Rth ⁇ + 20 nm. By making these ranges, it is possible to greatly improve the viewing angle of the IPS mode.
  • These retardation values can be appropriately adjusted by adding the fine particles B according to the present invention and the stretching operation.
  • the variation of Rth and the width of the distribution are preferably less than ⁇ 10%, more preferably less than ⁇ 5%. More preferably, it is less than ⁇ 1%, and most preferably, there is no fluctuation of Rth.
  • Nz (nx—nz) / (nx—ny)
  • d is the thickness of the film (nm)
  • refractive index nx the maximum refractive index in the plane of the film, also referred to as the refractive index in the slow axis direction
  • ny in the film plane, the direction perpendicular to the slow axis
  • Nz reffractive index of the film in the thickness direction
  • the retardation values (Ro) and (Rth) can be measured using an automatic birefringence meter.
  • KOBRA-21ADH Oji Scientific Instruments Co., Ltd.
  • RH 55% RH
  • the slow axis is preferably in the width direction ⁇ 1 ° of the film or in the longitudinal direction ⁇ 1 °. More preferably, it is ⁇ 0.7 ° with respect to the width direction or the longitudinal direction, and further preferably ⁇ 0.5 ° with respect to the width direction or the longitudinal direction. By setting this range, the contrast of the obtained liquid crystal display can be increased.
  • the IPS mode A polarizing plate protective film (optical film C) with optical characteristics of Ro, Rth force S0nm ⁇ Ro ⁇ 15 nm and 15nm ⁇ Rth ⁇ 15nm is provided on the opposite side of the polarizing plate across the liquid crystal cell. It is preferably used.
  • the optical film C having the optical characteristics is disposed between the liquid crystal cell and the polarizer, the viewing angle of the liquid crystal display device of the present invention can be further improved.
  • Optical film C is preferably a cellulose ester film.
  • optical film C is disclosed in Japanese Patent Application Laid-Open No. 2003-1 It can be produced by the method described in No. 2859. Specifically, it is preferable to adjust the retardation value, preferably including the polymer described in paragraphs [0032] to [0049] of JP-A-2003-12859 in the cellulose ester film. Can be done by type and quantity.
  • the optical film preferably contains the following polymer.
  • the polymer that can be used for the optical film C used in the present invention is a polymer obtained by polymerizing an ethylenically unsaturated monomer, an acrylic polymer, an acryl polymer having an aromatic ring in the side chain, or a cyclohexyl group.
  • An acrylic polymer in the side chain is preferred.
  • the polymer of the present invention having a weight average molecular weight of 500 to 10,000 is preferable because it has good compatibility with cellulose ester and neither evaporation nor volatilization occurs during film formation.
  • an acrylic polymer an acrylic polymer having an aromatic ring in the side chain, or an acrylic polymer having a cyclohexyl group in the side chain, if it is preferably 500 to 5,000, the above is listed.
  • the cellulose ester film after film formation is excellent in transparency and exhibits excellent performance as a protective film for polarizing plates with extremely low moisture permeability.
  • the weight average molecular weight of the polymer of the present invention is 500 or more and less than 10,000, the oligomer force is considered to be between low molecular weight polymers.
  • Such polymerization methods include a method using a peroxide polymerization initiator such as cumene peroxide t-butyl hydroperoxide, a method using a polymerization initiator in a larger amount than normal polymerization, and a polymerization initiator.
  • a method using a chain transfer agent such as a mercapto compound or carbon tetrachloride, a method using a polymerization terminator such as benzoquinone dinitrobenzene in addition to the polymerization initiator and further, Japanese Patent Application Laid-Open No. 2000-128911 or [ No. 2000 344823 [Bulk polymerization using a compound having one such thiol group and secondary hydroxyl group, or a polymerization catalyst using the compound and an organometallic compound in combination, etc. Both of which can Forces preferably used in the present invention In particular, the method described in the publication is preferred.
  • the monomer as the monomer unit constituting the polymer useful in the present invention is not limited to the following forces.
  • Examples of ethylenically unsaturated monomer units constituting a polymer obtained by polymerizing an ethylenically unsaturated monomer include: butyl esters such as vinyl acetate, propionate butyl, butyrate butyl, valerate butyl, and pivalic acid.
  • acrylic esters include methyl acrylate, ethyl acrylate, propyl acrylate (in 1), butyl acrylate (nis-t 1), pentyl acrylate ( nis—), hexyl acrylate (ni 1), heptyl acrylate (Ni 1), octyl acrylate (ni 1), acrylate (ni 1), myristyl acrylate (ni 1), cyclohexyl acrylate, acrylic acid (2-ethylhexyl), acrylic acid Benzyl, phenethyl acrylate, acrylic acid (epsilon), acrylic acid (2-
  • the polymer composed of the above-described monomers may be a copolymer or a homopolymer, and a homopolymer of vinylenoestenole, a copolymer of vinylenoestenole, or a copolymer of vinylenoestenole and acrylic acid or methacrylic acid ester is preferable.
  • an acrylic polymer (simply referred to as an acrylic polymer) is a homopolymer of acrylic acid or alkyl methacrylate having no monomer unit having an aromatic ring or a cyclohexyl group.
  • An acrylic polymer having an aromatic ring in the side chain is an acrylic polymer that always contains an acrylic acid or methacrylic acid ester monomer unit having an aromatic ring.
  • cyclohexyl group The acrylic polymer having a side chain is an acrylic polymer containing an acrylic acid or methacrylic acid ester monomer unit having a cyclohexyl group.
  • Examples of the acrylate monomer having no aromatic ring and cyclohexyl group include methyl acrylate, ethyl acrylate, propyl acrylate (in-), butyl acrylate (nis-t-), Pentyl acrylate (nis—), hexyl acrylate (ni 1), heptyl acrylate (ni 1), octyl acrylate (ni—), noryl acrylate (ni 1), myristyl acrylate ( ni 1), acrylic acid (2-ethylhexyl), acrylic acid ( ⁇ -force prolatathone), 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 above
  • the acrylic acid ester may be mentioned those obtained by changing the meth
  • the attalinole-based polymer is a homopolymer or copolymer of the above-mentioned monomers, but it is preferable that the alicyclic acid methyl ester monomer unit has 30% by mass or more, and the methacrylic acid methyl ester monomer unit strength is 0. It is preferable to have at least mass%. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.
  • acrylic acid or methacrylic acid ester monomers having an aromatic ring examples include acrylic acid file, methacrylic acid file, acrylic acid (2 or 4-chlorophenol), and methacrylic acid (2 or 4). Black and white), acrylic acid (2 or 3 or 4 ethoxycarbole), methacrylic acid (2 or 3 or 4 ethoxycarbole), acrylic acid ( ⁇ or m or ⁇ tolyl) ) Methacrylic acid (o or m or p tolyl) Benzyl acrylate, benzyl methacrylate, phenethyl acrylate, phenethyl methacrylate, acrylic acid (2-naphthyl), etc. benzyl acrylate, benzyl methacrylate Further, phenethyl acrylate and phenethyl methacrylate can be preferably used.
  • the acrylic acid or methacrylate ester monomer unit having an aromatic ring has 20 to 40% by mass, and 50 units of acrylic acid or methacrylate methyl ester monomer unit. preferable to have 80 mass 0/0! /,.
  • Examples of the acrylate monomer having a cyclohexyl group include cyclohexyl acrylate, cyclohexyl methacrylate, acrylic acid (4-methylcyclohexyl), methacrylic acid (4-methylcyclohexyl), and acrylic acid.
  • (4-ethyl cyclohexyl), methacrylic acid (4-ethyl cyclohexyl) and the like can be mentioned Cyclohexyl acrylate and cyclohexyl methacrylate can be preferably used.
  • the acrylic polymer having the side chain cyclohexyl group and 50 to 80 wt% have a 20-40 weight 0/0 of acrylic acid or methacrylic acid ester monomer unit having a cyclohexyl group speak It is preferable to do.
  • the polymer preferably has 2 to 20% by mass of an acrylic acid or methacrylic acid ester monomer unit having a hydroxyl group.
  • Polymers obtained by polymerizing the above ethylenically unsaturated monomers, acrylic polymers, acrylic polymers having an aromatic ring in the side chain, and acrylic polymers having a cyclohexyl group in the side chain are all cellulose. Excellent compatibility with esters, no evaporation or volatilization, excellent productivity, good retention as a protective film for polarizing plates, low moisture permeability, and excellent dimensional stability.
  • the acrylic acid or methacrylic acid ester monomer having a hydroxyl group of the present invention is a structural unit of a copolymer, not a homopolymer. In this case, it is preferable that the acrylic acid or methacrylic acid ester monomer unit having a hydroxyl group is contained in an acrylic polymer in an amount of 2 to 20% by mass.
  • a polymer having a hydroxyl group in the side chain can also be preferably used.
  • the monomer unit having a hydroxyl group the same force as the above-mentioned monomer, acrylic acid or methacrylic acid ester is preferred.
  • Hydroxyl group in polymer It is preferable to contain 2 to 20% by mass of the acrylic acid ester or methacrylic acid ester monomer unit in the polymer, more preferably 2 to 10% by mass.
  • the polymer as described above contains 2 to 20% by mass of the above-mentioned monomer unit having a hydroxyl group, of course, the compatibility with the cellulose ester, retention, and dimensional stability are excellent, and the moisture permeability is small. It is particularly excellent in adhesiveness with a polarizer as a protective film for a polarizing plate that is pressed by force, and has an effect of improving the durability of the polarizing plate.
  • At least one terminal of the main chain of the polymer has a hydroxyl group.
  • the method of having a hydroxyl group at the end of the main chain is not particularly limited as long as it has a hydroxyl group at the end of the main chain, but a radical having a hydroxyl group such as azobis (2-hydroxyethyl propylate).
  • a compound having one thiol group and a secondary hydroxyl group as disclosed in JP 2000-128911 or 2000-344823, or a polymerization catalyst using the compound and an organometallic compound in combination is preferred.
  • a polymer produced by a method related to the description in this publication is commercially available as Act Flow 'series manufactured by Soken Gakaku Co., Ltd., and can be preferably used.
  • the polymer having a hydroxyl group at the terminal and the polymer having a hydroxyl group at Z or a side chain have the effect of significantly improving the compatibility and transparency of the polymer in the present invention.
  • these polymers are preferably contained in the optical film C in an amount of 1 to 35% by mass. In particular, the content of 3 to 25% by mass controls the retardation value. Good to do! / These polymers may be contained in the optical film A.
  • Functional layers such as layers, smoothing layers, antiglare layers, gas barrier layers, optical compensation layers, etc. Also good.
  • various surface treatments such as corona discharge treatment, plasma treatment, and chemical treatment can be performed as necessary.
  • the chemical treatment includes operations such as simply applying an organic solvent rather than a chemically active chemical to dissolve or swell the surface of the cellulose ester film to improve the flatness.
  • the cellulose ester or additive may be co-extruded layers having different contents to form an optical film having a laminated structure.
  • a cellulose ester film having a structure of skin layer Z core layer Z skin layer can be produced.
  • fine particles such as a matting agent can be contained in the skin layer in a large amount or only in the skin layer.
  • a melt-extruded layer of diacetyl cellulose that can be easily saponified may be formed on the skin layer. Melt extrusion of diacetyl cellulose can be achieved according to known methods.
  • a low-volatile plasticizer and Z or an ultraviolet absorber may be included in the skin layer, and a plasticizer having excellent plasticity or an ultraviolet absorber having excellent ultraviolet absorption may be added to the core layer.
  • the glass transition temperature of the core layer may be lower than the glass transition temperature of the skin layer, which may have different glass transition temperatures.
  • the viscosity of the melt containing the cellulose ester during melt casting may be different between the skin layer and the core layer.
  • the viscosity of the skin layer may be greater than the viscosity of the core layer, or the viscosity of the core layer ⁇ the viscosity of the skin layer. If the viscosity of the thinner layer (usually the skin layer) is higher, a laminate with a uniform film thickness can be obtained.
  • At least one of the polarizing plates is the polarizing plate of the present invention.
  • the polarizing plate of the present invention may be used on both sides.
  • the polarizing plate of the present invention can be produced by a general method.
  • a polarizer which is a main component of a polarizing plate, is an element that passes only light having a plane of polarization in a certain direction.
  • a typical polarizing film that is currently known is a polyvinyl alcohol polarizing film. There are two types: polybutalolic film dyed with iodine and dichroic dye.
  • polarizing film a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially 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 40 111, preferably 5 to 30 / zm, and particularly preferably 5 to 25 / zm.
  • optical films A and B used in the present invention are bonded to form a polarizing plate. It is preferably bonded with a water-based adhesive mainly composed of completely acidified polyvinyl alcohol or the like.
  • a polarizing plate using the optical film C can be prepared in the same manner. For example, it can be produced in the same manner except that the optical film B is replaced with the optical film C.
  • the stretching direction (usually the longitudinal direction) shrinks, and the stretching and the vertical direction (usually normal) Extends in the width direction).
  • the stretching direction of the polarizing film is bonded to the casting direction (MD direction) of the polarizing plate protective film. Therefore, when the polarizing plate protective film is formed into a thin film, the stretching rate in the casting direction should be suppressed. is important. Since the optical film used in the present invention is excellent in dimensional stability, it is suitably used as such a polarizing plate protective film.
  • the polarizing plate can be constituted by further laminating a protective film on one surface of the polarizing plate and a separate film on the other surface.
  • the protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.
  • the protective film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate.
  • the separate film is used for the purpose of covering the adhesive layer to be bonded to the liquid crystal plate, and is used on the surface side of the polarizing plate to be bonded to the liquid crystal cell.
  • the optical film A and the optical film B stretched to control birefringence for the purpose of the present invention are disposed on both sides of the polarizer, respectively. It has a feature that can achieve the purpose.
  • the liquid crystal display device using the polarizing plate of the present invention is particularly effective for use in a multi-domain liquid crystal display device, more preferably a multi-domain liquid crystal display device with a birefringence mode. I can do it.
  • Multi-domain is a method that further divides the liquid crystal cell that constitutes one pixel into a plurality of parts. It is suitable for improving the viewing angle dependency and improving the symmetry of image display. “Okita, Yamauchi: Liquid Crystal, 6 (3), 303 (2002)”. The liquid crystal display cell is also shown in “Yamada, Hyundaira: Liquid Crystal, 7 (2), 184 (2003)”, but is not limited thereto.
  • the display quality of the display cell is preferably symmetric in human observation. Therefore, when the display cell is a liquid crystal display cell, the domain can be multiplied substantially giving priority to the symmetry on the observation side.
  • a known method can be used to divide the domain, and can be determined by a two-division method, more preferably a four-division method in consideration of the properties of the known liquid crystal mode.
  • the polarizing plate of the present invention has a multi-domestic vertical alignment (MVA) mode represented by a vertical alignment mode, in particular, a four-part MVA mode, and a known PVA (Patterned Vertical Alignment) multi-domained by electrode arrangement. ) Mode, CPA (Continuous Pinwheel Alignment) mode that combines electrode arrangement and chirality.
  • MVA multi-domestic vertical alignment
  • PVA Powerned Vertical Alignment
  • CPA Continuous Pinwheel Alignment
  • a proposal of an optically biaxial film is also disclosed in conformity with the OCB (Optical Compensated Bend) mode, and “T. Miya shita, T. Uchida: J. SID, 3 (1), 29 (1995) ”, the polarizing plate of the present invention can exhibit the effect of the present invention in display quality.
  • the polarizing plate (6b) of the present invention in which 2b is the optical film B and lb is the optical film A! /. Or 2a is optical film B and la is optical film A
  • the polarizing plate (6a) of the invention may be used, or both of them are preferably the polarizing plate of the invention.
  • the liquid crystal display device of the present invention having excellent visibility and an increased viewing angle by incorporating the polarizing plate of the present invention into a commercially available transverse electric field switching mode (hereinafter referred to as IPS mode) liquid crystal display device. Can be produced.
  • IPS mode transverse electric field switching mode
  • the IPS mode of the present invention includes a fringe-field switching (FFS) mode in the present invention, and the polarizing plate of the present invention can be incorporated in the same manner as the IPS mode, and has the same effect.
  • the liquid crystal display device of the present invention can be manufactured.
  • the polarizing plates are arranged above and below a pair of substrates located on both sides of the driving liquid crystal cell.
  • the arrangement of an optical film having a transmission axis direction of the slow axis Z polarizing plate, a polarizing plate, and a liquid crystal cell is preferred in the present invention and is an example of an IPS mode liquid crystal display device.
  • the liquid crystal display device has high performance as a device for colorization and moving image display, a liquid crystal display device using the polarizing plate of the present invention having the optical films A and B, particularly a large liquid crystal display device. Because the display quality is excellent in visibility, it is possible to display a moving image faithfully without fatigue.
  • the cellulose esters used are the following CE-1 to CE-4.
  • the film was stretched at a stretching temperature and a stretching ratio shown in Table 1 in the flow direction (MD) and 25% in the width direction (TD), and an optical film B1 having the film thickness and retardation value shown in Table 1 was obtained. Was made. In the same manner, the optical film B2- B10 was produced.
  • optical film B8 was prepared by mixing the following silicon dioxide fine particles (Aerosil R972V) in powder form.
  • Optical film B10 had a high haze value of 12% and could not be used as an optical film.
  • a suspension obtained by adding 60 parts by mass of methanol (20% by mass with respect to water) and 80 parts by mass of strontium hydroxide octahydrate (26.7% by mass with respect to water) to 300 parts by mass of water Prepared.
  • the suspension was stirred with a stirring motor (Shinto Kagaku Co., Ltd., Three-One Motor BLh600).
  • water bath with ultrasonic irradiation function Honda Electronics Co., Ltd. Ultrasonic waves were irradiated with a sonic cleaner W-113MK-IV).
  • silane coupling solution was prepared separately from this suspension. Acetic acid was added to 40 parts by mass of water to adjust the pH to about 5.3, and a silane coupling agent (3-glycidoxypropyltrimethoxysilane) was further added thereto, followed by stirring for about 3 hours.
  • the amount of the silane coupling agent was 30% by mass with respect to strontium carbonate.
  • the prepared silane coupling solution was added to the suspension, and surface treatment was performed while stirring with a stirring motor for 24 hours.
  • the suspension was filtered with suction through a filter paper of 0.1 ⁇ m pore size, the product was placed in 600 parts by weight of acetone, stirred for 24 hours, washed, and filtered again.
  • the product was dried in a vacuum dryer.
  • the dried crystal was observed with a scanning electron microscope (SEM) and confirmed to be strontium carbonate needle crystal particles with an aspect ratio of 10 with a major axis size of 150 nm and a minor axis size of 15 nm. did.
  • SEM scanning electron microscope
  • Dispersion medium 50 ⁇ m Zircoyu beads 400 parts by mass (filling rate 60%) Circumferential speed 10m / sec
  • the circulation rate of the dispersion was circulated at 60mlZmin for 5 hours, and the mill jacket was cooled with cooling water.
  • the amount of dispersion added was adjusted so that the amount shown in Table 1 was added as part by mass of fine particle-B with respect to cellulose ester.
  • Particulate rutile titanium oxide TTO— S— 3 Particle diameter minor axis 10 to 20 nm, major axis 50 to 15 Onm, aspect ratio 7 Ishihara Sangyo) 80 parts by mass
  • the above composition was dispersed with an ultrasonic disperser UH 300 (manufactured by SMT Co., Ltd.) at an output scale of 10 for 5 minutes continuously, and then dispersed with an Ultraapex mill UAMO 15 (Koto Kogyo) under the following conditions.
  • Dispersion media 50 m Zircon beads 400 g (filling rate 60%)
  • the dispersion was circulated for 5 hours at a circulation flow rate of 60 mlZmin, and the mill jacket was cooled with cooling water.
  • the addition amount of this dispersion was adjusted so as to be the amount shown in Table 1 as the addition part by mass of the fine particles-B with respect to the cellulose ester.
  • Silicon dioxide (SiO 2) fine particles are made of Aerosil R972V (Nippon Aerosil Co., Ltd .: primary particles)
  • the average diameter of the child was 16 nm and the apparent specific gravity was 90 gZ liter).
  • the microparticles were spherical and had an aspect ratio of 1 as observed with a scanning electron microscope (SEM).
  • polymer 7 was first prepared.
  • the temperature of the contents in the stirring frame was maintained at 70 ° C, and the polymerization was carried out for 4 hours.
  • the temperature of the reaction product was returned to room temperature, and 20 parts by mass of a 5% by mass benzoquinone tetrahydrofuran solution was added to the reaction product to stop the polymerization. While the polymer was gradually heated to 80 ° C. under reduced pressure with an evaporator, tetrahydrofuran, residual monomer, and residual zeolite compound were removed to obtain polymer 7.
  • the weight average molecular weight was 3,400.
  • the hydroxyl value (according to the measurement method described below) was 50.
  • i3-Mercaptopropionic acid 12 parts by mass (Measuring method of hydroxyl value) This measurement is in accordance with JIS K 0070 (1992). This hydroxyl value is determined based on the hydroxyl value required to neutralize acetic acid bonded to a hydroxyl group when 1 g of a sample is acetylated. Defined as the number of mg of potassium. Specifically, sample Xg (about 1 lg) is precisely weighed in a flask, and 20 ml of acetylating reagent (20 ml of acetic anhydride and 400 ml of pyridine) is added accurately.
  • Hydroxyl value ⁇ (B—C) X f X 28. 05ZX ⁇
  • B is the amount of 0.5 mol ZL of hydroxide / potassium ethanol solution (ml) used in the blank test
  • C is the amount of 0.5 mol ZL potassium hydroxide ethanol solution used for titration (ml)
  • f is the factor of 0.5 mol ZL potassium hydroxide ethanol solution
  • D is the acid value
  • 28. 05 is lmol of potassium hydroxide 1Z2 in quantity 56.11.
  • the screw rotation speed is lOOrpm
  • the temperature in the barrel (melting temperature) is set to 240 ° C
  • the material is melted
  • the fluidized cellulose ester composition is cast on a cooling drum maintained at 130 ° C.
  • the film was stretched 25% in the flow direction (MD) and 25% in the width direction (TD) to produce an optical film A1 having a thickness of 80 m.
  • Optical film A2 was produced in the same manner as optical film A1, except that the amount of polymer 7 added was changed to 20 parts by mass.
  • R o 0.2 nm
  • Rth -lOnm.
  • Optical film A3 was produced in the same manner as optical film A1, except that polymer 7 was changed to trimethylolpropane tribenzoate.
  • Optical film A4 was produced in the same manner as optical film A1, except that polymer 7 was changed to trimethylolpropane tribenzoate and the film thickness was changed to 40 ⁇ m.
  • An optical film A5 was produced in the same manner as the optical film A1, except that silicon dioxide fine particles were not added.
  • optical films Al, A2, and A5 have Ro and Rth within the predetermined ranges, and the optical film
  • an unstretched optical film by a heat shrink method was prepared by the following procedure.
  • a comparative optical film AF-32 with a film thickness of 65 m was obtained according to AF-31 except that a heat-shrinkable film was used.
  • a polybulal alcohol film having a thickness of 50 ⁇ m was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). Immerse this in an aqueous solution with a specific force of 0.075g of iodine, 5g of potassium yowi, and lOOg of water for 60 seconds, and then immerse it in an aqueous solution of 68 ° C that also has a specific force of 6g of potassium iodide, 7.5g of boric acid and 100g of water. did. This was washed with water and dried to obtain a polarizer.
  • Step 1 The optical film A immersed in a 2 mol ZL sodium hydroxide solution at 60 ° C for 90 seconds, washed with water, dried and then hatched on the side to be bonded to the polarizer (Optical films A1 to A5) and Optical film B (Optical films B1 to B9) were obtained.
  • Step 2 The polarizer was immersed in a polybulal alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
  • Step 3 Excess adhesive adhered to the polarizer in Step 2 was gently wiped off, and this was placed on each optical film processed in Step 1 and laminated.
  • Step 4 The optical film and the polarizer laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm 2 and a conveyance speed of about 2 mZ.
  • Step 5 A sample obtained by bonding the optical film prepared in Step 4 and the polarizer in a drier at 80 ° C was dried for 2 minutes to prepare a polarizing plate.
  • the comparative optical films (AF-31, AF-32) produced by the heat shrink method were bonded via the adhesive layer, and the backlight side was formed as shown in Fig. 2-2.
  • a polarizing plate was produced.
  • a polarizing plate As an optical film for a polarizing plate, a polarizing plate was produced using an optical film cut in a size of approximately 300 mm in the casting width and 200 mm in the width direction, and the environment at 23 ° C and 80% RH. Table 2 shows the results obtained by calculating the average value by measuring the floating height of the four corners of the polarizing plate several times (4 to 5 times). .
  • a level of ⁇ exhibits excellent characteristics because there is no curl when the polarizing plate is bonded to a liquid crystal display device.
  • the ⁇ level has a slight curl when the polarizing plate is bonded to a liquid crystal display device, and may include a bonding error, but there is no problem on the display image.
  • X is a polarizing plate curled so that this polarizing plate cannot be used in a liquid crystal display device.
  • the polarizing plate of the present invention has less curl and is excellent by evaluating the curl characteristics of the backlight side polarizing plate.
  • the optical film A5 does not contain fine particles, a blocking phenomenon occurs when the roll film is manufactured, and the optical film A5 is used as a long polarizing plate protective film in the manufacturing process of the polarizing plate. The transportability became unstable, and the uneven brightness was at the X level.
  • a liquid crystal panel to be evaluated for visibility is manufactured as follows, and it is special as a liquid crystal display device. Sex was evaluated.
  • the polarizing plates on both sides that had been pasted together were peeled off, and the prepared polarizing plates were placed on the IPS mode liquid crystal cell. Bonded to the surface.
  • the configuration of the liquid crystal display device is the configuration of Table 2 and Fig. 2, and the direction of bonding of the polarizing plate is that the slow axis of the optical films A and B and the transmission axis of the polarizer are
  • the liquid crystal display devices 101 to 112 were manufactured so as to be orthogonal (see Fig. 3) or parallel (see Fig. 4).
  • the viewing angle was similarly evaluated on the 15-inch LCD VL-1530S manufactured by Fujitsu.
  • the polarizing plate previously bonded to the liquid crystal television was peeled off, and each of the prepared polarizing plates was bonded to the glass surface of the liquid crystal cell in an MVA mode type liquid crystal cell.
  • the configuration of the liquid crystal display device is the configuration shown in Table 2 and Fig. 1, and the direction of bonding of the polarizing plates is the slow axis of the optical films A and B and the transmission axis of the polarizer.
  • Liquid crystal display devices 113 to 119 were fabricated in parallel (see Fig. 1).
  • the viewing angle of the liquid crystal display device was measured using EZ-contrast manufactured by ELDIM.
  • the contrast of the white and black display of the liquid crystal panel was ranked as follows for the contrast with respect to an inclination angle of 80 ° from the normal direction to the panel surface in all directions.
  • Contrast is more than 30 in all directions
  • the IPS mode liquid crystal display devices 103 and 107 to 112 of the comparative example and the MVA mode liquid crystal display devices 114 to 118 of the comparative example are stable display devices for a long period of time because they have both excellent viewing angle characteristics and uneven brightness, and also excellent curling characteristics of the polarizing plate.
  • liquid crystal display devices 107 to 109 using optical films (AF-31, AF-32) produced by the heat shrink method in comparison have a good level of viewing angle characteristics and poor flatness. Therefore, it can be seen that the curl characteristics and the luminance unevenness are bad.
  • Hitachi LCD TV Wooo W 17 LC50, an IPS mode LCD used in Example 1. Instead of LC50, Hitachi LCD TV Wooo, an FFS mode LCD.
  • a liquid crystal display device similar to that in Example 1 except that W32-L7000 was used was produced and the viewing angle characteristics were evaluated.
  • the optical film B of the polarizing plate of the present invention 0.2 mass% of silicon dioxide fine particles (Aerosil R972V) having an aspect ratio of 1 used for the optical film A is further added to the film resin.
  • Si dioxide fine particles A similar investigation was made with the added composition, and it was found that the transportability of the polarizing plate does not include silicon dioxide fine particles (Aerosil R972V)! It has been found that all the objects of the present invention are satisfied even without containing silicon fine particles.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)
  • Liquid Crystal (AREA)

Abstract

L'invention concerne une plaque de polarisation ayant un grand champ de vision et des caractéristiques de variation de luminance et de vrille améliorées. Elle concerne également un affichage à cristaux liquides. Elle porte spécifiquement sur une plaque de polarisation comportant un film optique disposé des deux côtés d'un polariseur, à savoir un film optique A est aménagé sur le côté éloigné du polariseur à partir d'une cellule à cristaux liquides et un film optique B est aménagé sur le côté proche du polariseur. Le film optique A contient de fines particules A et le film optique B contient de fines particules B. Si le facteur de forme de fines particules A s'exprime comme AR(A) et le facteur de forme de fines particules B s'exprime comme AR(B), ils satisfont à la relation suivante : AR(A) < AR(B).
PCT/JP2006/306085 2005-05-13 2006-03-27 Plaque de polarisation et affichage a cristaux liquides WO2006120807A1 (fr)

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JP2007056144A (ja) * 2005-08-24 2007-03-08 Fujifilm Corp セルロースエステル樹脂組成物
JP5374874B2 (ja) * 2007-02-26 2013-12-25 東ソー株式会社 光学フィルム用樹脂組成物およびこれからなる光学フィルム
JP2008304658A (ja) * 2007-06-07 2008-12-18 Konica Minolta Opto Inc 液晶表示装置
JP5062261B2 (ja) * 2007-10-04 2012-10-31 コニカミノルタアドバンストレイヤー株式会社 垂直配向型液晶パネル、垂直配向型液晶表示装置
JP5240990B2 (ja) * 2008-03-13 2013-07-17 日東電工株式会社 偏光解消フィルムおよびその製造方法、液晶表示装置
WO2010125834A1 (fr) * 2009-04-27 2010-11-04 コニカミノルタオプト株式会社 Plaque polarisante, procédé de production d'une plaque polarisante et dispositif d'affichage à cristaux liquides
JP2014098911A (ja) * 2013-12-24 2014-05-29 Konica Minolta Inc 偏光板およびこれを用いた液晶表示装置
JP2022178799A (ja) * 2021-05-21 2022-12-02 日東電工株式会社 円偏光板およびそれを用いた画像表示装置

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JP2004191956A (ja) * 2002-11-25 2004-07-08 Fuji Photo Film Co Ltd 反射防止フィルム、偏光板、及び液晶表示装置
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JP2003215337A (ja) * 2002-01-21 2003-07-30 Fuji Photo Film Co Ltd 光学補償フィルムおよびその製造方法、円偏光板、画像表示装置
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