JP2012198280A - Vertical alignment type liquid crystal display and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical alignment type liquid crystal display which achieves improvement in front contrast leading to power saving and reduces color shift and enlarges a viewing angle; and a method for manufacturing the same.SOLUTION: A vertical alignment type liquid crystal display includes a backlight, a vertical alignment type liquid crystal cell with a configuration in which a liquid crystal is held between two transparent substrates, and one polarizing plate on the display surface side of the vertical alignment type liquid crystal cell and one polarizing plate on the backlight side thereof, in which the vertical alignment type liquid crystal display satisfies predetermine conditions.

Description

  The present invention relates to a vertical alignment type liquid crystal display device that achieves an improvement in front contrast that leads to power saving, a small color shift, and a wide viewing angle, and a manufacturing method thereof.

  The liquid crystal display device is advantageous in that it is thinner and lighter than a CRT (Cathode Ray Tube), can be driven at a low voltage, and consumes less power. Therefore, liquid crystal display devices are used in various electronic devices such as televisions, notebook PCs (personal computers), desktop PCs, PDAs (mobile terminals), and mobile phones.

  In recent years, a vertical alignment type liquid crystal display device (also referred to as a “VA (vertical alignment) type”) liquid crystal display device using a vertical alignment type liquid crystal (a liquid crystal having a negative dielectric anisotropy) is compared with a conventional TN liquid crystal display device. Because of its excellent viewing angle characteristics, it has become widely used.

  In recent years, in this vertical alignment type liquid crystal display device, there has been a demand for further power saving, such as minimization of a light-shielding portion and color filter on array (hereinafter abbreviated as “COA”). High aperture ratio is being promoted.

  In addition, a method of increasing the transmittance of the polarizing plate has been proposed as a means of saving power, but if only the transmittance of the polarizing plate is increased, there is a problem that the degree of polarization decreases and the front contrast decreases. To do.

  In order to solve this, there is a method of suppressing depolarization by a film (protective film) disposed between a polarizer (also referred to as a “polarizing film”) and a liquid crystal cell, such as a retardation film and a viewing angle widening film. Although it is used, it can no longer satisfy the requirements.

  Patent Document 1 and Non-Patent Document 1 disclose that the front contrast is increased by the configuration of the retardation film. Although these methods suggest the possibility that the front contrast can be maintained even if the transmittance of the polarizing plate is increased, the front contrast improving means using these methods causes a very large color shift. Originally, the vertical alignment type liquid crystal display device has a small color shift, but this configuration is a method of eliminating the goodness inherent in the vertical alignment type liquid crystal display device.

  On the other hand, in recent years, in the manufacturing process of liquid crystal display devices, instead of the method of laminating a sheet-like polarizing plate on a liquid crystal panel, a “roll-to-panel manufacturing method” in which a roll-shaped polarizing plate is directly adhered is adopted. Although it has started, even in such a manufacturing method, it is desired that there is no variation in optical performance between lots of polarizing plates.

  In the present application, a polarizing plate manufactured in a rolled state is referred to as a “rolled polarizing plate”, and a piece cut from the polarizing plate to a predetermined dimension is referred to as a “single-sheet polarizing plate”.

JP 2010-54736 A

SID 2010 Digest of Technical Papers 55.1

  The present invention has been made in view of the above-described problems and situations, and the solution is to achieve a front contrast improvement that leads to power saving, and a vertical shift with a small color shift and a wide viewing angle. An alignment type liquid crystal display device and a manufacturing method thereof are provided.

  The above-mentioned problem according to the present invention is solved by the following means.

1. A vertical alignment type liquid crystal cell having a configuration in which a backlight, liquid crystal is sandwiched between two transparent substrates, and a vertical alignment type having polarizing plates one by one on the display surface side and the backlight side of the vertical alignment type liquid crystal cell A vertical alignment type liquid crystal display device which is a liquid crystal display device and satisfies the following requirements (a) to (c).
(A) The polarizing plate has two retardation films sandwiching a polarizer using polyvinyl alcohol, and the in-plane slow axis of the retardation film on the liquid crystal cell side of the polarizing plate is the polarized light. It is perpendicular to the absorption axis of the child.
(B) The retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell comprises a cellulose ester resin having a total acyl group substitution degree in the range of 2.0 to 2.7; An acid sugar ester compound and a polyester compound are contained, and the Nz coefficient is 3.0 or more.
(C) Of the transparent substrates, the transparent substrate on the backlight side has a color filter.

2. Regarding the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell, the in-plane position defined by the following formula (I) measured at 23 ° C. and 55% RH at a measurement wavelength of 590 nm. The retardation value Ro is in the range of 30 to 90 nm, the retardation value Rt in the thickness direction defined by the following formula (II) is in the range of 200 to 400 nm, and the polyester compound has an aromatic group terminal. 2. The vertical alignment type liquid crystal display device according to item 1, which is polyester or hydroxyl group-terminated polyester.
Formula _{(I): Ro = (n} x -n y) × d (nm)
Formula (II): Rt = {(n _x + n _y ) / 2−n _z } × d (nm)
[In the above formula, Ro represents an in-plane retardation value in the retardation film, and Rt represents a retardation in the thickness direction in the film. Further, d represents the thickness of the retardation film, n _x represents a refractive index of the maximum (slow axis direction) in a plane of the retardation film. n _y represents a refractive index in the direction perpendicular to the slow axis in the retardation film plane (fast axis direction), n _z represents the refractive index of the retardation film in the thickness direction. The measurement conditions are the same as above. ]
3. A method for manufacturing a vertical alignment type liquid crystal display device for manufacturing the vertical alignment type liquid crystal display device according to claim 1 or 2, wherein the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell A method for producing a vertical alignment type liquid crystal display device, comprising preparing a long roll-shaped polarizing plate having a phase difference film and bonding to the vertical alignment type liquid crystal cell by a roll-to-panel manufacturing method.

  By the above-described means of the present invention, it is possible to provide a vertical alignment type liquid crystal display device that achieves an improvement in front contrast leading to power saving, a small color shift, and a wide viewing angle, and a manufacturing method thereof. .

1 is a conceptual diagram showing an example of a configuration of a vertical alignment type (VA type) liquid crystal display device of the present invention. Conceptual diagram showing the roll-to-panel manufacturing method

  The vertical alignment liquid crystal display device of the present invention includes a backlight, a vertical alignment liquid crystal cell having a configuration in which liquid crystal is sandwiched between two transparent substrates, a display surface side and a backlight side of the vertical alignment liquid crystal cell. A vertical alignment type liquid crystal display device having polarizing plates one by one, which satisfies the requirements (a) to (c). This feature is a technical feature common to the inventions according to claims 1 to 3.

  As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell is measured at 590 nm at 23 ° C. and 55% RH. The in-plane retardation value Ro defined by the formula (I) measured in the above range is in the range of 30 to 90 nm, and the thickness direction retardation value Rt defined by the formula (II) is 200 to It is preferably within a range of 400 nm and the polyester compound is an aromatic group-terminated polyester or a hydroxyl group-terminated polyester. Furthermore, as a manufacturing method of the vertical alignment type liquid crystal display device of the present invention, a long roll-shaped polarizing plate having a retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell is prepared, It is preferable that it is a manufacturing method of the aspect bonded by the roll to panel manufacturing method with respect to the said vertical alignment type liquid crystal cell.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

(Vertical alignment type liquid crystal display device)
The vertical alignment liquid crystal display device of the present invention includes a backlight, a vertical alignment liquid crystal cell having a configuration in which liquid crystal is sandwiched between two transparent substrates, a display surface side and a backlight side of the vertical alignment liquid crystal cell. Each having a polarizing plate.

  The polarizing plate has two retardation films sandwiching a polarizer using polyvinyl alcohol, and the in-plane slow axis of the retardation film on the liquid crystal cell side of the polarizing plate is the polarizer. It is characterized by being orthogonal to the absorption axis.

(Polarizer)
When the retardation film according to the present invention is also used as a polarizer protective film, the polarizing plate can be produced by a general method. It is preferable that an adhesive layer is provided on the back side of the retardation film according to the present invention, and is bonded to at least one surface of a polarizer produced by immersing and stretching in an iodine solution.

  The retardation film according to the present invention may be used on the other surface, or another polarizer protective film may be used. For example, a commercially available cellulose ester film (for example, Konica Minoltack KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC8UE, KC4R-4, KC4FR-3, KC4FR-3, KC4FR-3, KC4FR-3, KC4FR-3, KC4FR-3, -1, KC8UY-HA, KC8UX-RHA, manufactured by Konica Minolta Opto Co., Ltd.) and the like are preferably used.

  A polarizer, which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass. A typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed.

  For the polarizer, a polyvinyl alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then preferably subjected to a durability treatment with a boron compound.

As the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer, a pressure-sensitive adhesive having a storage elastic modulus at 25 ° C. in the range of 1.0 × 10 ^{4 to} 1.0 × 10 ⁹ Pa in at least a part of the pressure-sensitive adhesive layer is used. It is preferable to use a curable pressure-sensitive adhesive that forms a high molecular weight body or a crosslinked structure by various chemical reactions after the pressure-sensitive adhesive is applied and bonded.

  Specific examples include, for example, urethane adhesives, epoxy adhesives, aqueous polymer-isocyanate adhesives, curable adhesives such as thermosetting acrylic adhesives, moisture-curing urethane adhesives, polyether methacrylate types, Examples include anaerobic pressure-sensitive adhesives such as ester-based methacrylate types and oxidized polyether methacrylates, cyanoacrylate-based instantaneous pressure-sensitive adhesives, and acrylate-peroxide-based two-pack type instantaneous pressure-sensitive adhesives.

  The pressure-sensitive adhesive may be a one-component type or a type in which two or more components are mixed before use.

  The pressure-sensitive adhesive may be a solvent system using an organic solvent as a medium, or may be an aqueous system such as an emulsion type, a colloidal dispersion type, or an aqueous solution type that is a medium containing water as a main component. It may be a solventless type. The density | concentration of the said adhesive liquid should just be suitably determined with the film thickness after adhesion, the coating method, the coating conditions, etc., and is 0.1-50 mass% normally.

<Phase difference film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell>
In the present invention, the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell comprises a cellulose ester having a total acyl group substitution degree in the range of 2.0 to 2.7, It contains an acid sugar ester compound and a polyester compound, and has an Nz coefficient of 3.0 or more.

In the present application, the “Nz coefficient” means the maximum refractive index (slow axis direction) in the plane of the retardation film, and the refractive index in the direction perpendicular to the slow axis (fast axis direction) in the retardation film plane. , and the refractive index of the retardation film in the thickness direction, respectively _{n x,} n y, when the _{n z,} in _{Nz = (n x -n z)} / value defined by _(n x -n _y) is there. That is, it is the value of the ratio of Ro to Rt (Rt / Ro + 0.5).

  In the present invention, the Nz coefficient is 3.0 or more. Preferably, it exists in the range of 3.5-4.5. By adjusting within this range, the effects of improving front contrast and viewing angle can be obtained.

  Means for adjusting the Nz coefficient within the above range include adding an additive or changing the compounding ratio of the materials, changing the film forming method (casting method, stretching temperature, magnification, film forming speed, etc.), etc. Can be mentioned.

In the present invention, the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell is defined by the following formula (I) measured at 23 ° C. and 55% RH at a measurement wavelength of 590 nm. The in-plane retardation value Ro is in the range of 30 to 90 nm, the thickness direction retardation value Rt defined by the following formula (II) is in the range of 200 to 400 nm, and the polyester compound is An aromatic group-terminated polyester or a hydroxyl group-terminated polyester is preferred.
Formula _{(I): Ro = (n} x -n y) × d (nm)
Formula (II): Rt = {(n _x + n _y ) / 2−n _z } × d (nm)
[In the above formula, Ro represents an in-plane retardation value in the retardation film, and Rt represents a retardation in the thickness direction in the film. Further, d represents the thickness of the retardation film, n _x represents a refractive index of the maximum (slow axis direction) in a plane of the retardation film. n _y represents a refractive index in the direction perpendicular to the slow axis in the retardation film plane (fast axis direction), n _z represents the refractive index of the retardation film in the thickness direction. The measurement conditions are the same as above. ]
In the present invention, the in-plane retardation value Ro is preferably in the range of 50 to 80 nm, and the retardation value Rt in the thickness direction is more preferably in the range of 250 to 350 nm.

  In addition, as the wavelength dispersibility of the retardation film, the ratio (Ro (450) / Ro (630)) of the phase difference Ro (450) at a wavelength of 450 nm to the phase difference Ro (630) at a wavelength of 630 nm is 0. It is preferably within the range of 90 or more and less than 1.00.

  The cellulose ester resin, the carboxylic acid sugar ester compound, and the polyester compound will be described later.

<Color filter>
The vertical alignment type liquid crystal display device of the present invention uses a vertical alignment type liquid crystal cell adopting a color filter on array (COA) system.

  The COA method includes, for example, a color filter integrated drive substrate in which a color filter is directly formed on a drive side substrate of a liquid crystal cell, and a counter electrode (conductive layer) as described in JP-A-10-206888. ) And a counter substrate with a spacer interposed therebetween, and a liquid crystal material is sealed in the gap, and a color filter is formed on the reflective electrode, and a bonding margin is provided in high definition. The yield and aperture ratio can be improved by widening.

<Vertical alignment type liquid crystal cell>
The vertical alignment type liquid crystal display device of the present invention has a vertical alignment type liquid crystal cell. As the liquid crystal cell according to the present invention, various conventionally known liquid crystal cells can be used.

  However, the present invention is characterized by using a vertically aligned liquid crystal cell having a configuration in which a liquid crystal having a negative dielectric anisotropy is sandwiched between two transparent substrates. One of the transparent substrates has a thin film transistor (TFT) and a color filter. Regarding this point, the configuration of the liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 2010-44362 is helpful. As the transparent substrate, conventionally known transparent glass or resin can be used.

  A liquid crystal cell is formed by sealing nematic liquid crystal having negative dielectric anisotropy between such glass substrates. As the nematic liquid crystal having negative dielectric anisotropy, conventionally known ones described in JP-A-2004-204133, JP-A-2004-250668, JP-A-2005-047980, etc. should be used. Can do.

  In the present invention, as the liquid crystal cell, for example, a nematic liquid crystal material having a negative dielectric anisotropy and having Δn = 0.0815 and Δε = −4.5 can be used between the upper and lower substrates.

  The thickness d of the liquid crystal layer is not particularly limited, but can be set to, for example, about 3.5 μm when the liquid crystal having the above characteristics is used.

  Note that in a vertical alignment type (VA type) liquid crystal display device, the addition of a chiral material generally used in a TN mode liquid crystal display device is rarely used to degrade dynamic response characteristics, but alignment failure It may be added to reduce the amount.

  In addition, the multi-domain structure is advantageous for adjusting the alignment of the liquid crystal molecules in the boundary region between the domains.

  Note that the “multi-domain structure” refers to a structure in which one pixel of a liquid crystal display device is divided into a plurality of regions. For example, in a vertical alignment type (VA type) liquid crystal display device, the liquid crystal molecules are tilted during white display, so the birefringence of the liquid crystal molecules when viewed from an oblique direction differs between the tilt direction and the opposite direction. Although a difference occurs in luminance and color tone, a multi-domain structure is preferable because viewing angle characteristics of luminance and color tone are improved.

  Specifically, each pixel is composed of two or more regions having different initial alignment states of liquid crystal molecules and averaged, whereby luminance and color tone bias depending on the viewing angle can be reduced. Further, the same effect can be obtained even if each pixel is constituted by two or more different regions where the alignment direction of liquid crystal molecules continuously changes in a voltage application state.

  In order to obtain a uniform viewing angle in all directions, the number of divisions may be increased. However, a substantially uniform viewing angle can be obtained by using four or more divisions. In particular, it is preferable that the polarizing plate absorption axis can be set at an arbitrary angle when dividing into eight.

(Resin film substrate used for polarizing plates, etc.)
As the resin film substrate used for the polarizing plate or the like according to the present invention, it is preferable to use a thermoplastic resin. Here, the “thermoplastic resin” refers to a resin that becomes soft when heated to the glass transition temperature or melting point and can be molded into a desired shape.

  General thermoplastic resins include cellulose esters, polyethylene (PE), high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene. (PS), polyvinyl acetate (PVAc), Teflon (registered trademark) (polytetrafluoroethylene, PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), etc., soluble in solvents It is preferable to dissolve the material appropriately and treat it by the method of the present invention.

  When strength and resistance to breakage are particularly required, polyamide (PA), nylon, polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate (PBT) ), Polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP), and the like.

  If higher heat distortion temperature and long-term use characteristics are required, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, polyetherether A ketone, thermoplastic polyimide (PI), polyamideimide (PAI), or the like can be used.

  In addition, it is possible to perform the kind of resin and the combination of molecular weight according to the use of this invention.

  As for the thickness of the resin film, it is preferable to select an appropriate thickness according to the application. The upper limit of the thickness is not particularly limited, but in the case of forming a film by a solution casting method, the upper limit is about 150 μm from the viewpoint of applicability, foaming, solvent drying, and the like.

  The resin substrate preferably has a total light transmittance of 90% or more, more preferably 93% or more. Moreover, as a realistic upper limit, it is about 99%. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film.

  Hereinafter, a particularly preferred resin in the present invention will be described in detail.

<Cellulose ester resin>
In the present invention, the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell has a cellulose ester resin ("" a total acyl group substitution degree in the range of 2.0 to 2.7. It is also called "cellulose ester").

  By setting it within the above range, a film having excellent transparency and excellent wavelength dispersion can be obtained within a preferable range of the Nz coefficient. Further, as means for adjusting within the above range, there are adjustment of esterification reaction conditions (time, temperature, sample concentration, etc.) and the like.

  In the present invention, when a cellulose ester resin is used for a retardation film other than the retardation film on the liquid crystal cell side, the total acyl group substitution degree of the cellulose ester resin may not necessarily be within the above range.

  In addition, the glucose unit which comprises cellulose with a β-1,4-glycoside bond has free hydroxyl groups (hydroxyl groups) at the 2nd, 3rd and 6th positions. The cellulose ester according to the present invention is a polymer (polymer) obtained by esterifying some or all of these hydroxyl groups (hydroxyl groups) with an acyl group.

  “Acyl group substitution degree” represents the total of the ratios of esterification of hydroxyl groups (hydroxyl groups) at the 2nd, 3rd and 6th positions of glucose as a repeating unit. Specifically, the degree of substitution is 1 when each of the hydroxyl groups (hydroxyl groups) at the 2nd, 3rd and 6th positions of cellulose is 100% esterified. Therefore, when all of the 2nd, 3rd and 6th positions of cellulose are 100% esterified, the degree of substitution is 3 at the maximum.

  In the present application, the “average acyl group substitution degree” refers to an acyl group substitution degree in which the acyl group substitution degree of a plurality of glucose units constituting the cellulose ester is expressed as an average value per unit.

  In addition, the measuring method of acyl group substitution degree can be measured according to ASTM-D817-96.

  Examples of the acyl group include acetyl group, propionyl group, butanoyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, and isobutanoyl. Group, tert-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like.

  Among these, an acetyl group, a propionyl group, a butanoyl group, a dodecanoyl group, an octadecanoyl group, a tert-butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, a cinnamoyl group, and the like are more preferable, and an acetyl group is particularly preferable. A propionyl group and a butanoyl group (when the acyl group has 2 to 4 carbon atoms), more preferably an acetyl group.

  Cellulose ester resins that can be used in the retardation film according to the present invention include cellulose (di, tri) acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, and It is preferably at least one selected from cellulose phthalates.

  Among these, particularly preferable cellulose esters include cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate.

  As a substitution degree of the mixed fatty acid ester, when having an acyl group having 2 to 4 carbon atoms as a substituent, when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group or butyryl group is Y, A cellulose resin containing a cellulose ester that simultaneously satisfies the following formulas (I) and (II) is preferable.

Formula (I) 1.5 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5
Furthermore, the cellulose ester used in the present invention preferably has a weight average molecular weight Mw / number average molecular weight Mn ratio of 1.5 to 5.5, particularly preferably 2.0 to 5.0, Preferably it is 2.5-5.0, More preferably, the cellulose ester of 3.0-5.0 is used preferably.

  The raw material cellulose of the cellulose ester resin according to 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 in arbitrary ratios, respectively.

  The cellulose ester according to the present invention can be produced by a known method. Generally, cellulose is esterified by mixing cellulose as a raw material, a predetermined organic acid (such as acetic acid or propionic acid), an acid anhydride (such as acetic anhydride or propionic anhydride), and a catalyst (such as sulfuric acid). The reaction proceeds until the triester is formed. In the triester, three hydroxyl groups (hydroxyl groups) of the glucose unit are substituted with an acyl acid of an organic acid. When two kinds of organic acids are used at the same time, a mixed ester type cellulose ester such as cellulose acetate propionate or cellulose acetate butyrate can be produced. Subsequently, the cellulose triester is hydrolyzed to synthesize a cellulose ester having a desired degree of acyl substitution. Thereafter, the cellulose ester is completed through steps such as filtration, precipitation, washing with water, dehydration, and drying.

  Specifically, it can be synthesized with reference to the method described in JP-A-10-45804.

  In the present invention, 1 g of cellulose ester resin is added to 20 ml of pure water (electric conductivity 0.1 μS / cm or less, pH 6.8), and the pH is 6 when stirred in a nitrogen atmosphere at 25 ° C. for 1 hr. It is preferable that the electric conductivity is 1 to 100 μS / cm.

<acrylic resin>
Methacrylic resin is also contained in the acrylic resin which can be used for the resin film base material used for retardation film, a polarizing plate, etc. which concern on this invention. Although it does not restrict | limit especially as resin, What consists of 50-99 mass% of methyl methacrylate units and 1-50 mass% of other monomer units copolymerizable with this is preferable.

  Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. Saturated acids, maleic acids, fumaric acids, unsaturated divalent carboxylic acids such as itaconic acid, aromatic vinyl compounds such as styrene, α-methylstyrene, and nucleus-substituted styrene, α, β- such as acrylonitrile, methacrylonitrile, etc. Examples thereof include unsaturated nitrile, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and the like. These can be used alone or in combination of two or more.

  Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable, and methyl acrylate and n-butyl acrylate are particularly preferably used.

  A commercially available thing can also be used as an acrylic resin. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dianal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Denki Kagaku Kogyo Co., Ltd.) and the like can be mentioned. .

<Cyclic olefin resin>
In the present invention, it is also preferable to use a cyclic olefin resin. Examples of the cyclic olefin resin include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof. Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

  Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. An addition polymer of a monomer having a monomer, an addition copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof.

  Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. Can be used.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene) and tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene. (Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0. 1 ^2,5 . 1 ^7,10 ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. In addition, these substituents may be the same or different and a plurality may be bonded to the ring. Monomers having a norbornene structure can be used singly or in combination of two or more.

  Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.

  Other monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof, cyclic conjugated dienes such as cyclohexadiene, cycloheptadiene, and the like. And derivatives thereof.

  A ring-opening polymer of a monomer having a norbornene structure and a ring-opening copolymer of a monomer having a norbornene structure and another monomer copolymerizable with the monomer have a known ring-opening polymerization catalyst. It can be obtained by (co) polymerization in the presence.

  Examples of other monomers that can be addition copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, Cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and the like. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable.

  An addition polymer of a monomer having a norbornene structure and an addition copolymer of another monomer copolymerizable with a monomer having a norbornene structure can be used in the presence of a known addition polymerization catalyst. It can be obtained by polymerization.

  A hydrogenated product of a ring-opening polymer of a monomer having a norbornene structure, a hydrogenated product of a ring-opening copolymer of a monomer having a norbornene structure and another monomer capable of ring-opening copolymerization thereof, Hydrogenated products of addition polymers of monomers having a norbornene structure, and hydrogenated products of addition copolymers of monomers having a norbornene structure and other monomers capable of addition copolymerization with these A known hydrogenation catalyst containing a transition metal such as nickel or palladium is added to the polymer solution, and the carbon-carbon unsaturated bond is preferably hydrogenated by 90% or more.

Among norbornene-based resins, as repeating units, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane-7 , 9-diyl-ethylene structure, the content of these repeating units is 90% by mass or more based on the entire repeating units of the norbornene resin, and the content ratio of X and the content ratio of Y The ratio of X: Y is preferably 100: 0 to 40:60. By using such a resin, it is possible to obtain a retardation film (optical film) having no dimensional change over a long period of time and having excellent optical property stability.

  The molecular weight of the cyclic olefin resin used in the present invention is appropriately selected according to the purpose of use. Polyisoprene or polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography using cyclohexane (toluene if the polymer resin does not dissolve) as a solvent, usually 20,000 to 150,000. . Preferably it is 25,000-100,000, More preferably, it is 30,000-80,000. When the weight average molecular weight is in such a range, the mechanical strength and molding processability of the film are highly balanced and suitable.

  The glass transition temperature of the cyclic olefin resin may be appropriately selected according to the purpose of use. From the viewpoint of durability and stretchability, it is preferably in the range of 130 to 160 ° C, more preferably 135 to 150 ° C.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the cyclic olefin resin is 1.2 to 3.5, preferably 1.5 to 3.0, from the viewpoint of relaxation time, productivity, and the like. More preferably, it is 1.8 to 2.7.

The cyclic olefin resin used in the present invention preferably has an absolute value of photoelastic coefficient of 10 × 10 ⁻¹² Pa ⁻¹ or less, more preferably 7 × 10 ⁻¹² Pa ⁻¹ or less, and more preferably 4 × 10. It is particularly preferably ⁻¹² Pa ⁻¹ or less. The photoelastic coefficient C is a value represented by C = Δn / σ where birefringence is Δn and stress is σ.

  In the present invention, it is preferable that the cyclic olefin resin does not substantially contain particles. Here, “substantially free of particles” means that even if particles are added to a film made of a cyclic olefin resin, the amount of increase in haze from the non-added state is allowed to be in the range of 0.05% or less. Means you can. In particular, the alicyclic polyolefin resin lacks affinity with many organic particles and inorganic particles. Therefore, when a cyclic olefin resin film to which particles exceeding the above range are added is stretched, voids are easily generated, and as a result, There is a risk that a significant increase in haze may occur.

<Polycarbonate resin>
In the present invention, various known polycarbonate resins can also be used. In the present invention, it is particularly preferable to use an aromatic polycarbonate. There is no restriction | limiting in particular about the said aromatic polycarbonate, and there will be no restriction | limiting in particular if it is an aromatic polycarbonate from which the various characteristics of a desired film are acquired.

  In general, a polymer material collectively referred to as polycarbonate is a generic term for a polymer material in which a polycondensation reaction is used in its synthesis method and the main chain is linked by a carbonic acid bond. , Phosgene, diphenyl carbonate and the like obtained by polycondensation. Usually, an aromatic polycarbonate represented by a repeating unit having 2,2-bis (4-hydroxyphenyl) propane called bisphenol-A as a bisphenol component is preferably selected, and various bisphenol derivatives should be appropriately selected. Thus, an aromatic polycarbonate copolymer can be constituted.

  In addition to this bisphenol-A, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 1,1 -Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) -2-phenyl Ethane, 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) sulfide, bis ( 4-hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) -3,3,5-tri Mention may be made of a chill cyclohexane, and the like.

  It is also possible to use an aromatic polyester carbonate partially containing terephthalic acid and / or isophthalic acid components. By using such a structural unit as a part of the structural component of the aromatic polycarbonate composed of bisphenol-A, the properties of the aromatic polycarbonate, such as heat resistance and solubility, can be improved. The present invention is also effective for coalescence.

  If the aromatic polycarbonate used here has a viscosity average molecular weight of 10,000 or more and 200,000 or less, it is suitably used. A viscosity average molecular weight of 20,000 to 120,000 is particularly preferred. If a resin having a viscosity average molecular weight lower than 10,000 is used, the mechanical strength of the resulting film may be insufficient, and if it has a high molecular weight of 400000 or more, the viscosity of the dope becomes too large, causing problems in handling. The viscosity average molecular weight can be measured by commercially available high performance liquid chromatography.

  The glass transition temperature of the aromatic polycarbonate according to the present invention is preferably 200 ° C. or higher in order to obtain a highly heat-resistant film, and more preferably 230 ° C. or higher. These can be obtained by appropriately selecting the copolymerization component. The glass transition temperature can be measured with a DSC apparatus (differential scanning calorimetric analyzer). For example, the baseline is unevenly determined by a temperature rising condition of 10 ° C./min with RDC220 manufactured by Seiko Instruments Inc. It is the temperature that starts

  In the present invention, the solvent used for the dope composition containing the aromatic polycarbonate is a mixed solvent containing 4 to 14 parts by mass of methylene chloride and a linear or branched aliphatic alcohol having 1 to 6 carbon atoms. It is preferable.

  The mixing amount of the linear or branched aliphatic alcohol having 1 to 6 carbon atoms is preferably 4 to 12 parts by mass. By using such a mixed solvent, the web is peeled off at a higher residual solvent concentration than before, thereby suppressing the generation of strong static electricity when the web is peeled off, thereby causing damage to the belt, film streaks, unevenness, and minuteness. Scratches can be prevented from occurring.

  The type of alcohol added is limited by the solvent used. It is a necessary condition that the alcohol and the solvent are compatible. These may be added alone or in combination of two or more. The alcohol in the present invention is preferably a linear or branched aliphatic alcohol having 1 to 6, preferably 1 to 4, more preferably 2 to 4 carbon atoms. Specific examples include methanol, ethanol, isopropanol, and tertiary butanol. Of these, ethanol, isopropanol, and tertiary butanol can achieve almost the same effect, but methanol is slightly less effective. Although the reason is not clear, it is presumed that the boiling point of the solvent, that is, the ease of flying during drying is related. Higher alcohols higher than that are not preferred because they have a high boiling point and are likely to remain after film formation.

  The amount of alcohol added must be carefully selected. These alcohols are completely poor in solubility in aromatic polycarbonate and are completely poor solvents. Therefore, it cannot be added too much, and should be the minimum amount that provides satisfactory peelability. As mentioned above, it is 4-14 mass parts with respect to a methylene chloride, Preferably it is 4-12 mass parts. When the addition amount is in the range of 4 to 14 parts by mass with respect to the amount of methylene chloride, the solubility of the solvent in the polymer and the dope stability are improved, and the effect of improving the peelability is increased.

  The present invention comprises the above methylene chloride and aliphatic alcohol in the dope composition, but other solvents can also be used. The remaining solvent is not particularly limited as long as it dissolves the aromatic polycarbonate at a high concentration and is compatible with alcohol, and is a low-boiling solvent. For example, as a solvent having a solubility in aromatic polycarbonate, in addition to methylene chloride, halogen solvents such as chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene, 1,3-dioxolane, 1, Examples include cyclic ether solvents such as 4-dioxane and tetrahydrofuran, and ketone solvents such as cyclohexanone.

  When using other solvent, there is no limitation in particular and it may use it in consideration of an effect. The effects here include mixing the solvent without sacrificing solubility and stability, for example, improving the surface properties of the film formed by the solution casting method (leveling effect), evaporation rate and system These include viscosity adjustment and crystallization suppression effects. What is necessary is just to determine the kind and addition amount of the solvent to mix by the degree of these effects, and you may use 1 type, or 2 or more types as a solvent to mix.

  Other solvents preferably used include halogen solvents such as chloroform and 1,2-dichloroethane, hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone, and ethyl acetate and butyl acetate. Examples include ester solvents, ether solvents such as ethylene glycol dimethyl ether and methoxyethyl acetate.

  The dope composition according to the present invention may be prepared by any method as long as a transparent solution having a low haze is obtained as a result. A predetermined amount of alcohol may be added to the aromatic polycarbonate solution dissolved in a certain solvent in advance, or the aromatic polycarbonate may be dissolved in a mixed solvent containing alcohol. However, as described above, since alcohol is a poor solvent, the method of adding the latter after the former may cause clouding of the dope due to the precipitation of the polymer. Therefore, the method of dissolving in the latter mixed solvent is preferable.

<Polyester resin>
The polyester resin that can be used in the present invention is obtained by polymerizing a dicarboxylic acid and a diol, and 70% or more of dicarboxylic acid structural units (constituent units derived from dicarboxylic acid) are derived from aromatic dicarboxylic acid, and 70% or more of the diol constituent units (constituent units derived from the diol) are derived from the aliphatic diol.

  The proportion of the structural unit derived from the aromatic dicarboxylic acid is 70% or more, preferably 80% or more, more preferably 90% or more.

  The proportion of the structural unit derived from the aliphatic diol is 70% or more, preferably 80% or more, and more preferably 90% or more. Two or more polyester resins may be used in combination.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, naphthalenedicarboxylic acid such as 2,7-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. 3,4'-biphenyldicarboxylic acid and the like and ester-forming derivatives thereof.

  As the polyester resin, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid, and monocarboxylic acids such as benzoic acid, propionic acid, and butyric acid can be used without departing from the object of the present invention.

  Examples of the aliphatic diol include ethylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, and the like, and ester-forming derivatives thereof.

  As the polyester resin, monoalcohols such as butyl alcohol, hexyl alcohol, and octyl alcohol, and polyhydric alcohols such as trimethylolpropane, glycerin, and pentaerythritol can be used as long as the object of the present invention is not impaired.

  A known esterification method or transesterification method can be applied to the production of the polyester resin. Examples of the polycondensation catalyst used in the production of the polyester resin include known antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds such as germanium oxide, titanium compounds such as titanium acetate, and aluminum compounds such as aluminum chloride. Although it can, it is not limited to these.

  Preferred polyester resins include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polyethylene-2,6-naphthalene dicarboxylate resin, polyethylene-2, 6-naphthalene dicarboxylate-terephthalate copolymer resin, polyethylene-terephthalate-4,4'-biphenyldicarboxylate resin, poly-1,3-propylene-terephthalate resin, polybutylene terephthalate resin, polybutylene-2,6-naphthalene There are dicarboxylate resins and the like.

  More preferable polyester resins include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polybutylene terephthalate resin, and polyethylene-2,6-naphthalene dicarboxylate. Resin.

  The intrinsic viscosity of the polyester resin (phenol / 1,1,2,2-tetrachloroethane = value measured at 25 ° C. in a 60/40 mass ratio mixed solvent) is preferably 0.7 to 2.0 dl / g, more Preferably it is 0.8-1.5 dl / g. Since the molecular weight of the polyester resin is sufficiently high when the intrinsic viscosity is 0.7 or more, the molded product comprising the polyester resin composition obtained by using the polyester resin has mechanical properties necessary for the molded product and is transparent. Property is improved. When the intrinsic viscosity is 2.0 or less, the moldability is good.

(Carboxylic acid sugar ester compound)
The retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell according to the present invention is characterized by containing a carboxylic acid sugar ester compound as one of its constituent components.

  In the present application, the “carboxylic acid sugar ester compound” refers to a compound having an ester bond derived from a hydroxyl group (hydroxyl group) of a saccharide and a carboxyl group of a carboxylic acid.

  Examples of the carboxylic acid structural unit constituting the carboxylic acid sugar ester compound include aromatic carboxylic acids such as methylbenzoic acid (toluic acid), aromatic substituted aliphatic carboxylic acids such as phenylacetic acid, and fatty acids such as stearic acid. These carboxylic acids may be substituted with an alkoxy group, an alkylthio group, a halogen atom, a cyano group, or a nitro group.

  Examples of preferred aromatic carboxylic acids include aromatic monocarboxylic acids, cinnamic acid, benzylic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid having an alkyl group or alkoxy group introduced into the benzene ring of benzoic acid such as benzoic acid or toluic acid. Examples thereof include aromatic monocarboxylic acids having two or more benzene rings such as acid and tetralincarboxylic acid, or derivatives thereof. More specifically, xylyl acid, hemelic acid, mesitylene acid, prenylic acid, γ -Isoduric acid, duryl acid, mesitic acid, α-isoduric acid, cumic acid, α-toluic acid, hydroatropic acid, atropic acid, hydrocinnamic acid, salicylic acid, o-anisic acid, m-anisic acid, p-anisic acid, Creosote acid, o-homosalicylic acid, m-homosalicylic acid, p-homosalicylic acid, o-pyrocatechuic acid β-resorcylic acid, vanillic acid, isovanillic acid, veratromic acid, o-veratrumic acid, gallic acid, asaronic acid, mandelic acid, homoanisic acid, homovanillic acid, homoveratrumic acid, o-homoveratormic acid, phthalonic acid, p-coumaric acid Among them, benzoic acid is particularly preferable.

  Preferred aliphatic carboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, Tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, mellicic acid, laccellic acid, etc., undecylen Examples thereof include unsaturated fatty acids such as acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octenoic acid.

  The saccharides constituting the carboxylic acid sugar ester compound usually include monosaccharides (monosaccharides), disaccharides (disaccharides), and oligosaccharides bonded with 3 to 6 monosaccharides, and among them, the number of carbon atoms is 6 ~ 48 saccharides are preferred, and monosaccharides and disaccharides are more preferred. Specific examples of monosaccharides include glucose, fructose, arabinose, mannose, and sorbitol, and examples of disaccharides include sucrose and maltose. From the viewpoint of supplying raw materials, glucose, fructose and sucrose are particularly preferable, and sucrose is most preferable.

  These saccharides have a plurality of hydroxyl groups (hydroxyl groups) in the molecule, and can form ester bonds with the aforementioned carboxylic acid structural units.

  In particular, when sucrose is used as a saccharide, there are 8 hydroxyl groups (hydroxyl groups) in the sucrose molecule, but the average number of ester bonds (also referred to as “average ester substitution degree”) is 1. 0.0 or more, preferably 3.0 to 8.0, and more preferably 3.5 to 7.5.

  In the present invention, it is particularly preferable to contain a compound represented by the following general formula (1) and having a total average substitution degree in the range of 3.5 to 7.5.

In general formula (1), R _{1 to} R ₈ represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group, or a substituted or unsubstituted arylcarbonyl group, and R _{1 to} R ₈ are the same. It may or may not be.

Preferable specific examples of the compound represented by the general formula (1) include compounds shown in Table 1. In addition, R described in the following table represents any one of R _{1 to} R ₈ . As the substituent for the alkylcarbonyl group and the arylcarbonyl group, substituents such as a phenyl group and an alkoxy group included in the alkylcarbonyl group and the arylcarbonyl group shown in the following table are preferable.

  Although the compound represented by the said General formula (1) and a reference compound are described below, it is not limited to these.

  (Synthesis Example: Synthesis of Compound According to the Present Invention)

A four-headed colben equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube was mixed with 34.2 g (0.1 mol) of sucrose, 180.8 g (0.8 mol) of benzoic anhydride, 379. 7 g (4.8 mol) was charged, the temperature was raised while bubbling nitrogen gas from a nitrogen gas introduction tube with stirring, and an esterification reaction was carried out at 70 ° C. for 5 hours. Next, the inside of the Kolben was depressurized to 4 × 10 ² Pa or less, and after excess pyridine was distilled off at 60 ° C., the inside of the Kolben was depressurized to 1.3 × 10 Pa or less and the temperature was raised to 120 ° C. Most of the acid and benzoic acid formed were distilled off. Then, 1 L of toluene and 300 g of a 0.5% by mass aqueous sodium carbonate solution were added, and the mixture was stirred at 50 ° C. for 30 minutes and then allowed to stand to separate a toluene layer. Finally, 100 g of water is added to the collected toluene layer, and after washing with water at room temperature for 30 minutes, the toluene layer is separated, and toluene is distilled off at 60 ° C. under reduced pressure (4 × 10 ² Pa or less). A mixture of A-1, A-2, A-3, A-4 and A-5 was obtained. When the obtained mixture was analyzed by HPLC and LC-MASS, A-1 was 7% by mass, A-2 was 58% by mass, A-3 was 23% by mass, A-4 was 9% by mass, A-5. Was 3% by mass. A part of the obtained mixture was purified by column chromatography using silica gel to obtain A-1, A-2, A-3, A-4 and A-5 having a purity of 100%, respectively. It was.

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

<Aromatic group-terminated polyester compound>
In the present invention, the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell contains a polyester compound. As the polyester compound, various polyester compounds conventionally contained in optical films can be used.

  In the present invention, it is particularly preferable to use an aromatic group-terminated polyester compound represented by the following general formula (I).

General formula (I): B- (GA) _n -GB
(In the formula, B is an arylcarboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A Represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.)
In general formula (I), an arylcarboxylic acid residue represented by B and an alkylene glycol residue or oxyalkylene glycol residue or arylglycol residue represented by G, an alkylenedicarboxylic acid residue or aryldicarboxylic acid represented by A And is obtained by the same reaction as a normal polyester compound.

  As the arylcarboxylic acid component of the aromatic group-terminated polyester-based compound used in the present invention, for example, benzoic acid, p-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, There are normal propyl benzoic acid, aminobenzoic acid, acetoxybenzoic acid and the like, and these can be used as one kind or a mixture of two or more kinds, respectively.

  Examples of the alkylene glycol component having 2 to 12 carbon atoms of the aromatic group-terminated polyester compound that can be used in the present invention include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and 1,2-butanediol. 1,3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propane Diol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-di) Methylol heptane), 3-methyl-1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl 1 There are 3-pentanediol, 2-ethyl 1,3-hexanediol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, etc. These glycols are used as one or a mixture of two or more.

  In particular, an alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of excellent compatibility with a cellulose ester.

  Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the aromatic group-terminated polyester compound include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. Can be used as one or a mixture of two or more.

  Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms of the aromatic group-terminated polyester compound include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These are each used as one kind or a mixture of two or more kinds.

  Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5 naphthalene dicarboxylic acid, and 1,4 naphthalene dicarboxylic acid.

  In the aromatic group-terminated polyester compound used in the present invention, n is preferably 1 or more and 100 or less, and the number average molecular weight is preferably 300 to 1500, more preferably 400 to 1000. .

  The acid value is 0.5 mgKOH / g or less, the hydroxyl (hydroxyl) value is 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl (hydroxyl) value is 15 mgKOH / g or less. is there.

  The aromatic group-terminated polyester compound represented by the general formula (I) according to the present invention is preferably contained in an amount of 0.5 to 30% by mass with respect to the cellulose ester.

  Specific examples of the aromatic group-terminated polyester compound that can be used in the present invention are shown below, but the present invention is not limited thereto.

  The cellulose ester film according to the present invention contains the sugar ester compound according to the present invention in an amount of 0.5 to 30% by mass of the cellulose ester film in order to suppress the fluctuation of the retardation value and stabilize the display quality. It is preferable to contain 5-30 mass% especially.

  The content of the aromatic group-terminated polyester compound and the sugar ester compound represented by the general formula (I) according to the present invention can be selected in a mass ratio of 99: 1 to 1:99, and the whole of both compounds. The amount is preferably 1 to 40% by mass relative to the cellulose ester.

<Hydroxyl-terminated polyester>
In the present invention, the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell contains a polyester compound. As the polyester compound, various polyester compounds conventionally contained in optical films can be used.

  In the present invention, as the polyester compound, a polyester having a hydroxyl group at the terminal portion of the chemical structural formula as represented by the following general formula (II) (referred to as “hydroxyl group-terminated polyester”) is also preferable.

(In the formula, B represents a linear or branched alkylene or cycloalkylene group having 2 to 6 carbon atoms, A represents an aromatic ring having 6 to 14 carbon atoms, and n represents a natural number of 1 or more. )
The compound represented by the above formula is obtained from a dicarboxylic acid having an aromatic ring (also referred to as an aromatic dicarboxylic acid) and a linear or branched alkylene or cycloalkylene diol having 2 to 6 carbon atoms, and both ends are It is characterized by not being sealed with monocarboxylic acid.

  Examples of the aromatic dicarboxylic acid having 6 to 16 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3- And naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and the like. Among these, 2,6-naphthalenedicarboxylic acid and 4,4′-biphenyldicarboxylic acid are preferable.

  Examples of the linear or branched alkylene or cycloalkylene diol having 2 to 6 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 1,3-butanediol. 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol 1,4-cyclohexanedimethanol and the like. Among these, ethanediol, 1,2-propanediol, 1,3-propanediol, and 1,3-butanediol are preferable.

  Among these, A is preferably a naphthalene ring or a biphenyl ring which may have a substituent, from the viewpoint of obtaining the effects of the present invention. Here, the substituent is an alkyl group having 1 to 6 carbon atoms, an alkenyl group, or an alkoxyl group.

  The hydroxyl (hydroxyl) value (OH value) of the polyester compound according to the present invention is preferably 100 mgKOH / g or more and 500 mgKOH / g or less, and more preferably 170 mgKOH / g to 400 mgKOH / g. Whether the hydroxyl (hydroxyl) value is larger or smaller than this range, the compatibility with cellulose acetate having a low acetyl substitution degree is lowered.

  If it is larger than this range, the hydrophobicity of the polyester compound becomes larger. If it is smaller than this range, the intermolecular interaction (hydrogen bonding, etc.) between the polyester compounds becomes stronger, so that precipitation in the film proceeds. it is conceivable that.

  Moreover, the measurement of a hydroxyl (hydroxyl group) value can apply the acetic anhydride method etc. of Japanese Industrial Standard JISK1557-1: 2007.

  The number average molecular weight (Mn) of the polyester compound according to the present invention can be calculated from the following formula.

Mn = (number of hydroxyl groups (hydroxyl groups) in the molecule) × 56110 / (hydroxyl (hydroxyl group) value)
= 2 × 56110 / (hydroxyl (hydroxyl group) value)
The polyester compound according to the present invention is either a hot melt condensation method by a polyesterification reaction or transesterification reaction of the above dicarboxylic acid and a diol by a conventional method, or an interfacial condensation method of an acid chloride of these acids and glycols. It can be easily synthesized by a method.

  Below, the polyester compound which concerns on this invention is illustrated.

  The compound represented by the general formula (II) is preferably added in an amount of 1% by mass to less than 5% by mass with respect to cellulose acetate.

(Other additives)
The thermoplastic resin substrate according to the present invention can contain various compounds as additives depending on the purpose. For example, it contains retardation increasing agent, plasticizer, antioxidant, acid scavenger, light stabilizer, UV absorber, optical anisotropy control agent, matting agent, antistatic agent, release agent, etc. Can be made.

  The retardation increasing agent is preferably an aromatic compound having at least two aromatic rings. The aromatic compound is preferably used in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the resin. And it is preferable to use in 0.05-15 mass parts, and it is still more preferable to use in 0.1-10 mass parts. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring. The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring). The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring. Details of these are described in JP-A No. 2004-109410, JP-A No. 2003-344655, JP-A No. 2000-275434, JP-A No. 2000-1111914, JP-A No. 12-275434, and the like.

(Matting agent)
The thermoplastic resin substrate according to the present invention may be added with fine particles as a matting agent in order to prevent scratching or deterioration of transportability when the produced film is handled. preferable.

  As fine particles, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, Examples thereof include magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable.

  The average primary particle diameter of the fine particles is preferably 5 to 400 nm, and more preferably 10 to 300 nm. These may be mainly contained as secondary aggregates having a particle size of 0.05 to 0.3 μm, and may be contained as primary particles without being aggregated if the particles have an average particle size of 80 to 400 nm. preferable. The content of these fine particles in the film is preferably 0.01 to 1% by mass, particularly preferably 0.05 to 0.5% by mass. In the case of a retardation film (optical film) having a multilayer structure formed by the co-casting method, it is preferable that the surface contains this amount of fine particles.

  Silicon dioxide fine particles are commercially available, for example, under the trade names Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.). it can.

  Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

  Examples of the resin include a silicone resin, a fluororesin, and an acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of reducing the friction coefficient while keeping the haze of the retardation film (optical film) low. In the retardation film (optical film) according to the present invention, the dynamic friction coefficient of at least one surface is preferably 0.2 to 1.0.

(Method for producing retardation film)
As a method for producing the resin film substrate according to the present invention as a film, production methods such as a normal inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, and a hot press method can be used. However, the solution casting method by the casting method and the melt casting method are preferable from the viewpoints of suppression of coloring, suppression of defects of foreign matters, suppression of optical defects such as die lines, and the like.

  Hereinafter, the production method for producing the retardation film according to the present invention will be described in detail.

<Method for producing retardation film by solution casting method>
《Organic solvent》
When the retardation film (optical film) according to the present invention is produced by the solution casting method, the organic solvent useful for forming the dope is not limited as long as it dissolves a thermoplastic resin such as a cellulose ester resin. Can be used.

  For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, ethyl lactate, lactic acid , Diacetone alcohol and the like, methylene chloride, methyl acetate, ethyl acetate, acetone, ethyl lactate and the like are preferably used. That.

  In addition to the organic solvent, the dope may contain 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels, facilitating peeling from the metal support, and when the proportion of alcohol is small, the dissolution of the thermoplastic resin in a non-chlorine organic solvent system is promoted. There is also a role.

  In particular, the thermoplastic resin should be a dope composition in which at least a total of 10 to 45 mass% is dissolved in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. preferable.

  Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

  Hereinafter, a preferred method for forming a retardation film (optical film) according to the present invention (hereinafter also simply referred to as “film”) will be described.

1) Dissolution Step In this step, a thermoplastic resin and other additives are dissolved in an organic solvent mainly composed of a good solvent for the thermoplastic resin while stirring to form a dope.

  For the dissolution of the thermoplastic resin, a method carried out at normal pressure, a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9-95544, JP-A-9-95557 Alternatively, various dissolution methods such as a cooling dissolution method as described in JP-A-9-95538 and a high-pressure method as described in JP-A-11-21379 can be used. The method of pressurizing at a boiling point or higher is preferred.

  Recycled material is a finely pulverized film, which is generated when the film is formed, cut off on both sides of the film, or the original film that has been speculated out due to scratches, etc. Reused.

2) Casting process An endless metal belt, such as a stainless steel belt or a rotating metal drum, which supports the dope is fed to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump) and supported infinitely. This is a step of casting a dope from a pressure die slit to a casting position on the body.

  A pressure die that can adjust the slit shape of the die base portion and can easily make the film thickness uniform is preferable. Examples of the pressure die include a coat hanger die and a T die, and any of them is preferably used. The surface of the metal support is a mirror surface. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.

3) Solvent evaporation step In this step, the web (the dope is cast on the casting support and the formed dope film is called a web) is heated on the casting support to evaporate the solvent.

  To evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back side of the support by a liquid, a method of transferring heat from the front and back by radiant heat, etc. High efficiency and preferable. A method of combining them is also preferably used. The web on the support after casting is preferably dried on the support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or to heat by means such as infrared rays.

  From the viewpoint of surface quality, moisture permeability, and peelability, it is preferable to peel the web from the support within 30 to 120 seconds.

4) Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.

  The temperature at the peeling position on the metal support is preferably 10 to 40 ° C, more preferably 11 to 30 ° C.

  In addition, it is preferable that the residual solvent amount at the time of peeling of the web on the metal support at the time of peeling is peeled in the range of 50 to 120% by mass depending on the strength of drying conditions, the length of the metal support, and the like. If the web is peeled off at a time when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling will be lost, and slippage and vertical stripes are likely to occur due to the peeling tension. The amount of solvent is determined.

  The residual solvent amount of the web is defined by the following formula.

Residual solvent amount (%) = (mass before web heat treatment−mass after web heat treatment) / (mass after web heat treatment) × 100
Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.

  The peeling tension at the time of peeling the metal support and the film is usually 196 to 245 N / m. However, when wrinkles easily occur at the time of peeling, it is preferable to peel with a tension of 190 N / m or less. It is preferable to peel at a minimum tension that can be peeled to 166.6 N / m, and then peel at a minimum tension to 137.2 N / m, and particularly preferably peel at a minimum tension to 100 N / m.

  In the present invention, the temperature at the peeling position on the metal support is preferably -50 to 40 ° C, more preferably 10 to 40 ° C, and most preferably 15 to 30 ° C.

5) Drying and stretching step After peeling, using a drying device that alternately passes the web through rolls arranged in the drying device and / or a tenter stretching device that clips and transports both ends of the web with clips. Dry the web.

  Generally, the drying means blows hot air on both sides of the web, but there is also a means for heating by applying microwaves instead of the wind. Too rapid drying tends to impair the flatness of the finished film. Drying at a high temperature is preferably performed from about 8% by mass or less of the residual solvent. Throughout the drying is generally carried out at 40-250 ° C. It is particularly preferable to dry at 40 to 160 ° C.

  When using a tenter stretching apparatus, it is preferable to use an apparatus that can independently control the film gripping length (distance from the start of gripping to the end of gripping) left and right by the left and right gripping means of the tenter. In the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve planarity.

  It is also preferable to provide a neutral zone between different temperature zones so that the zones do not interfere with each other.

  In addition, extending | stretching operation may be divided | segmented and implemented in multiple steps, and it is also preferable to implement biaxial stretching in a casting direction and a width direction. When biaxial stretching is performed, simultaneous biaxial stretching may be performed or may be performed stepwise.

  In this case, stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any one of the stages. Is also possible. That is, for example, the following stretching steps are possible.

-Stretch in the casting direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction-Stretch in the width direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction Simultaneous biaxial stretching includes stretching in one direction and contracting the other while relaxing the tension. The preferable draw ratio of simultaneous biaxial stretching can be taken in the range of x1.01 times to x1.5 times in both the width direction and the longitudinal direction.

  When the tenter is used, the residual solvent amount of the web is preferably 20 to 100% by mass at the start of the tenter, and it is preferable to perform drying while applying the tenter until the residual solvent amount of the web becomes 10% by mass or less. More preferably, it is 5% by mass or less.

  30-160 degreeC is preferable, as for the drying temperature in the case of performing a tenter, 50-150 degreeC is more preferable, and 70-140 degreeC is the most preferable.

  In the tenter process, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film. The temperature distribution in the width direction in the tenter process is preferably within ± 5 ° C, and within ± 2 ° C Is more preferable, and within ± 1 ° C. is most preferable.

6) Winding step This is a step of winding the film as a film by a winder after the amount of residual solvent in the web is 2% by mass or less. By reducing the amount of residual solvent to 0.4% by mass or less, dimensional stability can be improved. A good film can be obtained. It is particularly preferable to wind up at 0.00 to 0.10% by mass.

  As a winding method, a generally used method may be used. There are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like.

  The film according to the present invention is preferably a long film. Specifically, the film is about 100 m to 10000 m, and is usually in the form of a roll. Moreover, it is preferable that the width | variety of a film is 1.3-4m, and it is more preferable that it is 1.4-2.5m.

  Although there is no restriction | limiting in particular in the film thickness of the film concerning this invention, It is preferable that it is 20-200 micrometers.

<Method for producing retardation film by melt casting method>
The method in the case of manufacturing the resin film base material which concerns on this invention as a retardation film by the melt-casting film forming method is demonstrated.

<Melted pellet manufacturing process>
The composition constituting the thermoplastic resin film used for melt extrusion is usually preferably kneaded in advance and pelletized.

  Pelletization may be performed by a known method. For example, a dry thermoplastic resin and an additive depending on the purpose are fed to an extruder with a feeder and kneaded using a uniaxial or biaxial extruder, and then formed into a strand from a die. Can be extruded, water-cooled or air-cooled, and then cut.

  It is important to dry the raw material before extruding to prevent decomposition of the raw material. In particular, since the cellulose ester easily absorbs moisture, it is preferable to dry it at 70 to 140 ° C. for 3 hours or more with a dehumidifying hot air dryer or a vacuum dryer to keep the moisture content at 200 ppm or less, and further 100 ppm or less.

  Additives may be fed into the extruder and fed into the extruder, or may be fed by individual feeders. In order to mix a small amount of additives such as an antioxidant uniformly, it is preferable to mix them in advance.

  The antioxidant may be mixed with each other, and if necessary, the antioxidant may be dissolved in a solvent, impregnated with a thermoplastic resin and mixed, or mixed by spraying. May be.

A vacuum nauter mixer or the like is preferable because drying and mixing can be performed simultaneously. Further, if the contact with air, such as the exit from the feeder unit or die, it is preferable that the atmosphere such as dehumidified air and dehumidified N ₂ gas.

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

  A film is formed using the pellets obtained as described above. It is also possible to feed the raw material powder directly to the extruder with a feeder and form a film as it is without pelletization.

<Process for extruding molten mixture from die to cooling roll>
First, using a single-screw or twin-screw type extruder, the melt temperature Tm when extruding the pellet is about 200 to 300 ° C., filtered through a leaf disk type filter or the like to remove foreign matter, and then from the T-die. Coextruded into a film, solidified on a cooling roll, and cast while pressing with an elastic touch roll.

  When introducing into the extruder from the supply hopper, it is preferable to prevent oxidative decomposition and the like under vacuum, reduced pressure, or inert gas atmosphere. Tm is the temperature of the die exit portion of the extruder.

  When foreign matter such as scratches or plasticizer aggregates adheres to the die, streak-like defects may occur. Such defects are also referred to as die lines, but in order to reduce surface defects such as die lines, it is preferable to have a structure in which the resin retention portion is minimized in the piping from the extruder to the die. . It is preferable to use a die that has as few scratches as possible inside the lip.

  The inner surface that contacts the molten resin such as an extruder or a die is preferably subjected to surface treatment that makes it difficult for the molten resin to adhere to the surface by reducing the surface roughness or using a material having a low surface energy. Specifically, a hard chrome plated or ceramic sprayed material is polished so that the surface roughness is 0.2 S or less.

  In the present invention, there is no particular limitation on the cooling roll, but it is a roll having a structure in which a heat medium or a coolant that can be controlled in temperature flows with a highly rigid metal roll, and the size is not limited. It is sufficient that the film is large enough to cool the film, and the diameter of the cooling roll is usually about 100 mm to 1 m.

  Examples of the surface material of the cooling roll include carbon steel, stainless steel, aluminum, and titanium. Further, in order to increase the hardness of the surface or improve the releasability from the resin, it is preferable to perform a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying.

  The surface roughness of the chill roll surface is preferably 0.1 μm or less in terms of Ra, and more preferably 0.05 μm or less. The smoother the roll surface, the smoother the surface of the resulting film. Of course, it is preferable that the surface processed is further polished to have the above-described surface roughness.

  In the present invention, examples of the elastic touch roll include JP-A-03-124425, JP-A-08-224772, JP-A-07-1000096, JP-A-10-272676, WO97 / 028950, JP-A-11-235747, A silicon rubber roll coated with a thin film metal sleeve can be used as described in Japanese Unexamined Patent Application Publication No. 2002-36332, Japanese Patent Application Laid-Open No. 2005-172940 and Japanese Patent Application Laid-Open No. 2005-280217.

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

<Extension process>
In the present invention, the film obtained as described above can be further stretched 1.01 to 3.0 times in at least one direction after passing through the step of contacting the cooling roll.

  Preferably, the film is stretched 1.1 to 2.0 times in both the longitudinal (film transport direction) and lateral (width direction) directions.

  As a method of stretching, a known roll stretching machine or tenter can be preferably used. In particular, when the retardation film (optical film) also serves as a polarizer protective film, the stretching direction is set to the width direction, which is preferable because lamination with the polarizing film can be performed in a roll form.

  By stretching in the width direction, the slow axis of the retardation film (optical film) becomes the width direction.

  Usually, the draw ratio is 1.1 to 3.0 times, preferably 1.2 to 2 times, and the drawing temperature is usually in the temperature range of Tg to Tg + 50 ° C. of the resin constituting the film.

  The stretching is preferably performed under a uniform temperature distribution controlled in the longitudinal direction or the width direction. The temperature is preferably within ± 2 ° C, more preferably within ± 1 ° C, and particularly preferably within ± 0.5 ° C.

  When the film-like resin film produced by the above method is used as a retardation film, the film is formed in the longitudinal direction or width for the purpose of adjusting the retardation (retardation) of the retardation film (optical film) and reducing the dimensional change rate. It may be contracted in the hand direction.

  In order to shrink in the longitudinal direction, for example, there is a method in which the film is shrunk by temporarily clipping out the width stretching and relaxing in the longitudinal direction, or by gradually narrowing the interval between adjacent clips of the transverse stretching machine.

  The uniformity in the slow axis direction is also important, and the angle is preferably −5 to + 5 ° with respect to the film width direction, more preferably in the range of −1 to + 1 °, and particularly −0. It is preferably in the range of 5 to + 0.5 °, particularly preferably in the range of −0.1 to + 0.1 °. These variations can be achieved by optimizing the stretching conditions.

  The retardation film according to the present invention is preferably a long film. Specifically, the retardation film has a thickness of about 100 m to 10000 m, and is usually provided in a roll shape. Moreover, it is preferable that the width | variety of a film is 1.3-4m, and it is more preferable that it is 1.4-2.5m.

  There is no restriction | limiting in particular in the film thickness of the retardation film which concerns on this invention, It is preferable to change according to the objective. For example, when using for a polarizer protective film, it is preferable that it is 20-200 micrometers.

(Manufacturing method of liquid crystal display device)
The retardation film according to the present invention is particularly preferably used for a liquid crystal display device produced by a roll-to-panel manufacturing method.

  In the present application, the “roll-to-panel manufacturing method” means that the length of the liquid crystal cell and the width of the liquid crystal cell are not cut in advance in both the vertical and horizontal sizes of the liquid crystal cell. This is a manufacturing method in which a polarizing plate is directly fed out from a long roll corresponding to the width of the film, and bonded to a liquid crystal cell, and then cut into a liquid crystal cell size with a laser cutter or the like (see FIG. 2). In this case, the laminating roll is pressed when laminating the polarizing plate to the liquid crystal cell, but since it is a long polarizing plate, generally an unreasonable force is easily applied at the time of laminating, and unevenness is present in the polarizing plate. Although it is likely to occur, when the retardation film satisfying the above-described conditions according to the present invention is used, unevenness is hardly generated, and variation in optical performance between lots is negligible.

  Hereinafter, although an example is given and the present invention is explained, the present invention is not limited to these.

<Preparation of carboxylic acid sugar ester compound>
Four-headed Kolben equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube were charged with 34.2 g (0.1 mol) of sucrose, 180.8 g (0.6 mol) of benzoic anhydride, 379. 7 g (4.8 mol) was charged, the temperature was raised while bubbling nitrogen gas from a nitrogen gas introduction tube with stirring, and an esterification reaction was carried out at 70 ° C. for 5 hours.

Next, the inside of the Kolben was depressurized to 4 × 10 ² Pa or less, and after excess pyridine was distilled off at 60 ° C., the inside of the Kolben was depressurized to 1.3 × 10 Pa or less and the temperature was raised to 120 ° C. Most of the acid and benzoic acid formed were distilled off. Finally, 100 g of water was added to the collected toluene layer, and after washing with water at room temperature for 30 minutes, the toluene layer was collected, and toluene was distilled off at 60 ° C. under reduced pressure (4 × 10 ² Pa or less). Then, when the average substitution degree was measured from the area ratio of the chart showing the substitution degree distribution by high performance liquid chromatography by a conventional method, each of the exemplified compounds A-1 to A-5 (see [Chemical Formula 4]) was 1.3%. , 13.4%, 13.1%, 31.7%, 40.5%, and the average substitution degree was 5.5.

  Each of the carboxylic acid sugar ester compounds having the substitution degree shown in Table 1 was prepared in the same manner except that the amount of benzoic anhydride was adjusted.

<Production of Cellulose Ester Film 101>
<Fine particle dispersion 1>
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by weight Ethanol 89 parts by weight The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

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

Methylene chloride 99 parts by mass Fine particle dispersion 1 5 parts by mass A main dope liquid 1 having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose ester A was added to a pressurized dissolution tank containing a solvent while stirring. This was heated and dissolved completely with stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

<Composition of main dope solution 1>
Methylene chloride 340 parts by weight Ethanol 64 parts by weight Cellulose acetate (acetyl group substitution degree 2.00; number average molecular weight Mn = 50000) 100 parts by weight Sugar ester compound: benzyl saccharose 9 parts by weight average substitution degree 5.5 Polyester compound ( 5) (Refer to [Chemical formula 5]) 3 parts by mass Particulate additive liquid 1 1 part by mass The above was put into the sealed main dissolution vessel 1 and dissolved while stirring to prepare a dope solution.

  On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film was 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m. The peeled retardation film was stretched 33% in the width direction using a tenter while applying heat at 142 ° C. The residual solvent at the start of stretching was 15%.

  Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m. As described above, a retardation film 101 having a dry film thickness of 76 μm was obtained.

<Preparation of retardation films 102 to 124>
Hereinafter, production conditions such as the materials, stretch ratio, and temperature shown in Table 1 were changed to adjust to a desired retardation, and retardation films 102 to 124 were produced.

<< Measurement of retardation Ro and Rt >>
A sample of 35 mm × 35 mm was cut out from each of the obtained samples, conditioned at 23 ° C. and 55% RH for 2 hours, and measured with an automatic birefringence meter (KOBRA21DH, Oji Scientific Co., Ltd.) from the vertical direction at 590 nm. And an extrapolated value of the retardation value measured in the same manner while tilting the film surface. In addition, the following retardation film 127 of Table 2 was added as a comparative example. The measurement results are shown in Table 2.

  The retardation Ro in the in-plane direction is measured by making light having a wavelength of 590 nm incident in the normal direction of the film in KOBRA21ADH. When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rt is calculated by the following method.

  Retardation Rt in the thickness direction is the above-mentioned Ro, in-plane slow axis (determined by KOBRA21ADH) as an inclination axis (rotation axis) (in the absence of a slow axis, any direction in the film plane) The rotational axis of the film normal direction is from the normal direction to 50 degrees on one side in 10 degree steps, and light of a wavelength of 590 nm is incident from each inclined direction to measure a total of 6 points. The value was calculated by KOBRA21ADH based on the retardation value, the assumed value of the average refractive index, and the input film thickness value.

In the above measurement, those whose average refractive index is not known can be measured with an Abbe refractometer. By inputting the assumed value and the film thickness of the average refractive index, the _KOBRA21ADH, were calculated _{n x, n y, n z} .

  From the above table, it can be seen that the retardation film according to the present invention is a film having a reverse wavelength dispersion having a retardation desirable as a retardation film and decreasing in retardation as the wavelength increases.

<Preparation of polarizing plate>
Next, a polarizer, a cellulose ester film described in Table 2 below, and Konica Minolta Tack KC4UY (Konica Minolta Opto Co., Ltd. cellulose ester film) are bonded to the polarizing plate 201 according to the following steps 1 to 5. 209 was produced. Similarly, Konica Minolta Tack KC4UY (cellulose ester film manufactured by Konica Minolta Opto Co., Ltd.) was obtained in the same manner as the cellulose ester film 101 except that the following main dope liquid compositions 2 and 3 were used. Were bonded together to produce polarizing plates 210 and 211. In addition, a polarizing plate 212 in which a polarizer and Konica Minolta Tac KC4UY (a cellulose ester film manufactured by Konica Minolta Opto Co., Ltd.) were bonded to only one side was also produced. Further, except that a commercially available cyclic cycloolefin-based film (trade name: ZEONOR, manufactured by Nippon Zeon Co., Ltd.) having been subjected to corona treatment (referred to as retardation film 127) was used in the same manner as the polarizing plate 201, A polarizing plate 213 was produced. Table 2 shows the retardation value of the cyclic cycloolefin film at this time.

<Production of Cellulose Ester Film 125>
<Composition of main dope liquid 2>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose acetate (acetyl group substitution degree 2.88; Mn = 14000)
100 parts by mass Polymer Y1 12 parts by mass Polyester compound (5) (see [Chemical Formula 5]) 5 parts by mass Fine particle additive liquid 1 4 parts by mass <Synthesis of Polymer Y>
Bulk polymerization was performed by the polymerization method described in JP-A No. 2000-128911. That is, the following methyl acrylate or methyl methacrylate is introduced as a monomer Ya into a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, a charging port, and a reflux condenser, and nitrogen gas is introduced to introduce nitrogen gas into the flask. The following thioglycerol substituted with was added with stirring.

100 parts by weight of methyl acrylate or methyl methacrylate 5 parts by weight of thioglycerol After addition of thioglycerol, the temperature of the contents is appropriately changed, polymerization is performed for 4 hours, the contents are returned to room temperature, and 20% by weight of a 5% by weight benzoquinone tetrahydrofuran solution is added thereto. Part of the mixture was added to stop the polymerization. The contents were transferred to an evaporator, and tetrahydrofuran, residual monomer and residual thioglycerol were removed under reduced pressure at 80 ° C. to obtain polymers Y1 to Y5.

Y1 to Y5 are as follows.
Y1: Monomer Ya: methyl acrylate, weight average molecular weight: 1000
Y2: Monomer Ya: Methyl methacrylate, Weight average molecular weight: 1000
Y3: Monomer Ya: Methyl acrylate, Weight average molecular weight: 500
Y4: Monomer Ya: Methyl acrylate, Weight average molecular weight: 3000
Y5: Monomer Ya: Methyl acrylate, Weight average molecular weight: 4000
The dope solution was prepared, then filtered, and uniformly cast on a stainless steel band support at a temperature of 22 ° C. and a width of 2 m using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the amount of residual solvent reached 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m. The peeled cellulose ester web was evaporated at 35 ° C., slit to 1.6 m width, and then dried at a drying temperature of 135 ° C. while stretching 1.1 times in the width direction with a tenter. At this time, the residual solvent amount when starting stretching with a tenter was 10%. After stretching with a tenter, relaxation was performed at 130 ° C. for 5 minutes, and then drying was completed while transporting a drying zone at 120 ° C. and 130 ° C. with many rolls, slitting to a width of 1.5 m, and a width of 10 mm at both ends of the film. A knurling process having a height of 5 μm was applied, and the cellulose ester film 125 was obtained by winding it around a 6-inch inner diameter core with an initial tension of 220 N / m and a final tension of 110 N / m. The draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.1 times. The residual solvent amount of the cellulose ester film was 0.1%, the film thickness was 40 μm, Ro was 0.3, Rt was 0.7, and the number of turns was 4000 m.

<Preparation of Cellulose Ester Film 126>
<Composition of main dope solution 3>
Methylene chloride 300 parts by mass Ethanol 40 parts by mass Cellulose acetate propionate (acyl group total substitution degree 2.75, acetyl group substitution degree 0.19, propionyl group substitution degree 2.56; Mn = 75000) 30 parts by mass Dialnal BR85 (Mitsubishi Rayon Co., Ltd.) 70 parts by mass The produced dope solution was uniformly cast on a stainless steel band support at a temperature of 22 ° C. and a width of 2 m using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the amount of residual solvent reached 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m.

  The solvent was evaporated from the peeled acrylic resin web at 35 ° C., slit to 1.6 m width, and then dried at a drying temperature of 135 ° C. while stretching 1.1 times in the width direction with a tenter. At this time, the residual solvent amount when starting stretching with a tenter was 10%. After stretching with a tenter and relaxing at 130 ° C for 5 minutes, drying was completed while transporting the drying zone at 120 ° C and 140 ° C with a number of rolls, slitting to a width of 1.5 m, and 10 mm wide at both ends of the film. A knurling process having a thickness of 5 μm was performed, and a cellulose ester film 126 was obtained by winding it around a 6-inch inner diameter core with an initial tension of 220 N / m and a final tension of 110 N / m.

  The draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.1 times. The residual solvent amount of the cellulose ester film was 0.1%, the film thickness was 60 μm, Ro was 0.5, Rt was 0.8, and the winding length was 4000 m.

<< Polarizing plate manufacturing process >>
Step 1: Soaked in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to obtain a saponified cellulose ester film on the side to be bonded to the polarizer.

  Process 2: The said polarizer was immersed in the polyvinyl alcohol adhesive tank of 2 mass% of solid content for 1-2 seconds.

  Step 3: Excess adhesive adhered to the polarizer in Step 2 was lightly wiped off, and this was placed on the cellulose ester film treated in Step 1.

Step 4: Step 3 Cellulose ester film laminated with the polarizer and the pressure backside cellulose ester film 20-30 N / cm ^2, the conveyance speed was pasted at approximately 2m / min.

  Step 5: A sample prepared by laminating the polarizer prepared in Step 4 in the dryer at 80 ° C., each retardation film described in Table 3 and Konica Minolta Tack KC4UY for 2 minutes, and polarizing plates 201 to 213 were produced. .

<Production of liquid crystal display device>
A liquid crystal panel for viewing angle measurement was produced as follows, and the characteristics as a liquid crystal display device were evaluated.

  The liquid crystal cell is formed so that the polarizing plates 201 to 213 prepared in the above-described manner are peeled off from both sides of the VA mode type liquid crystal display device (BRAVIA KDL-52W5 manufactured by SONY) in advance, and the prepared polarizing plates 201 to 213 are combined as shown in Table 4, respectively. Bonded to both sides of the glass surface.

  At that time, the direction of bonding of the polarizing plate is performed so that the surface of the retardation film is on the liquid crystal cell side and the absorption axis is directed in the same direction as the polarizing plate previously bonded, Liquid crystal display devices 301 to 313 were produced. In the liquid crystal cell of this liquid crystal display device, a color filter and a thin film transistor are arranged on one side of a transparent substrate, which is a cell of the liquid crystal display device of the present invention.

  Subsequently, for the VA mode type liquid crystal display device (BRAVIA KDL-40V5 manufactured by SONY), the polarizing plates on both sides which were previously bonded in the same manner are peeled off, and the prepared polarizing plates 201 to 213 are respectively shown in Table 4 Bonded so that the surface of the retardation film is on the liquid crystal cell side and the absorption axis is in the same direction as the previously bonded polarizing plate on both sides of the glass surface of the liquid crystal cell Then, liquid crystal display devices 314 to 326 were respectively produced. The liquid crystal cell of this liquid crystal display device is a comparative example of the liquid crystal cell of the liquid crystal display device of the present invention, in which the color filter and the thin film transistor are arranged on different transparent substrates.

<Evaluation of contrast>
In an environment of 23 ° C. and 55% RH, the backlight of each liquid crystal display device was lit continuously for one week, and then the contrast was measured. For the measurement, a spectral radiance meter CS-2000 manufactured by Konica Minolta Sensing Co., Ltd. was used, the luminance in the normal direction of the display screen of white display and black display was measured with a liquid crystal display device, and the ratio was taken as the contrast.

[Evaluation criteria for contrast]
A: Contrast 6500 or more B: Contrast 5500 or more and less than 6500 Δ: Contrast 4500 or more and less than 5500 ×: Contrast less than 4500 << Evaluation of viewing angle >>
About each produced said liquid crystal display device, the viewing angle was measured using the measuring machine (EZ-Contrast160D, ELDIM company make). White display and black display were measured with a liquid crystal display device, and at the azimuth angles φ = 45 ° and 135 °, the minimum angle of the tilt angle θ with respect to the front direction at which the contrast was 100 was taken as the viewing angle.

[Evaluation criteria for viewing angle]
◎: 65 ° or more ○: 60 ° or more and less than 65 ° Δ: 55 ° or more and less than 60 ° x: less than 55 ° << Evaluation of Color Shift >>
About each produced said liquid crystal display device, the color fluctuation was measured using the measuring machine (EZ-Contrast160D, ELDIM company make). In the CIE1976, L ^* a ^* b ^* color specification, the maximum value of the color difference ΔE ^* a ^* b ^* at a tilt angle θ = 60 ° with respect to the front direction was compared.

[Evaluation criteria for color shift]
◎: ΔE ^* a ^* b ^* is less than 5 ○: ΔE ^* a ^* b ^* is 5 or more and less than 10 Δ: ΔE ^* a ^* b ^* is 10 or more and less than 15 ×: ΔE ^* a ^* b ^* is 15 or more

  From the results shown in Table 4, it is clear that the liquid crystal display devices 301 to 304, 311 and 312 according to the present invention are liquid crystal display devices excellent in contrast, viewing angle and color shift.

<Relationship between slit method of polarizing plate and luminance unevenness>
The polarizing plate 210 is 1151 mm wide and the polarizing plate 203 is slit to a 647 mm width using a laser slitter to produce a polarizing plate roll 210A1 having a width of 1151 mm and a polarizing plate roll 203B1 having a width of 647 mm. did.

  This was set in the manufacturing system of the liquid crystal display device which is a panel bonding apparatus of a roll-shaped polarizing plate, and roll-bonded to ten liquid crystal cells (liquid crystal display devices 401-410). In addition, 10 polarizing plates 210 and 203 were cut into 52-inch sizes, and the sheets were similarly bonded to 10 liquid crystal cells (liquid crystal display devices 411 to 420).

  Each was returned to the original backlight configuration, and the luminance unevenness was evaluated.

<village>
Applicable liquid crystal display device is wet-heated at 50 ° C / 90% RH for 24 hours, and the luminance unevenness (strength) in black display 2 hours after lighting the backlight and the effect of displaying the image are visually evaluated according to the following criteria. did.
◎: Brightness unevenness is not visible ○: Weak brightness unevenness is visible but I am not interested in image display △: Brightness unevenness is strong, but I am hardly interested in image display ×: Brightness unevenness is strong and I am concerned about image display The evaluation results are shown in Table 5.

  As is apparent from the results shown in Table 5, as a method for manufacturing a vertical alignment type liquid crystal display device for manufacturing the vertical alignment type liquid crystal display device of the present invention, at least one of the retardation film A and the retardation film B is used. It turns out that the manufacturing method of the aspect which prepares the elongate roll-shaped polarizing plate which has this retardation film, and is bonded with the roll to panel manufacturing method with respect to the said liquid crystal cell is preferable.

DESCRIPTION OF SYMBOLS 1, 9 Polarizer 2 Retardation film 3, 7 Transparent substrate 4 Liquid crystal with negative dielectric anisotropy 5 Color filter 6 Thin film transistor 8 Retardation film 10 Backlight 11, 13 Polarizing plate 12 Liquid crystal cell 20 Roll-like polarizing plate 21 Bonding roll

Claims (3)

A vertical alignment type liquid crystal cell having a configuration in which a backlight, liquid crystal is sandwiched between two transparent substrates, and a vertical alignment type having polarizing plates one by one on the display surface side and the backlight side of the vertical alignment type liquid crystal cell A vertical alignment type liquid crystal display device which is a liquid crystal display device and satisfies the following requirements (a) to (c).
(A) The polarizing plate has two retardation films sandwiching a polarizer using polyvinyl alcohol, and the in-plane slow axis of the retardation film on the liquid crystal cell side of the polarizing plate is the polarized light. It is perpendicular to the absorption axis of the child.
(B) The retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell comprises a cellulose ester resin having a total acyl group substitution degree in the range of 2.0 to 2.7; An acid sugar ester compound and a polyester compound are contained, and the Nz coefficient is 3.0 or more.
(C) Of the transparent substrates, the transparent substrate on the backlight side has a color filter. Regarding the retardation film on the liquid crystal cell side of the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell, the in-plane position defined by the following formula (I) measured at 23 ° C. and 55% RH at a measurement wavelength of 590 nm. The retardation value Ro is in the range of 30 to 90 nm, the retardation value Rt in the thickness direction defined by the following formula (II) is in the range of 200 to 400 nm, and the polyester compound has an aromatic group terminal. 2. The vertical alignment type liquid crystal display device according to claim 1, wherein the vertical alignment type liquid crystal display device is polyester or hydroxyl group-terminated polyester.
Formula _{(I): Ro = (n} x -n y) × d (nm)
Formula (II): Rt = {(n _x + n _y ) / 2−n _z } × d (nm)
[In the above formula, Ro represents an in-plane retardation value in the retardation film, and Rt represents a retardation in the thickness direction in the film. Further, d represents the thickness of the retardation film, n _x represents a refractive index of the maximum (slow axis direction) in a plane of the retardation film. n _y represents a refractive index in the direction perpendicular to the slow axis in the retardation film plane (fast axis direction), n _z represents the refractive index of the retardation film in the thickness direction. The measurement conditions are the same as above. ]   A method for manufacturing a vertical alignment type liquid crystal display device for manufacturing the vertical alignment type liquid crystal display device according to claim 1, wherein the polarizing plate on the display surface side of the vertical alignment type liquid crystal cell is on the liquid crystal cell side. A method for producing a vertical alignment type liquid crystal display device, comprising preparing a long roll-shaped polarizing plate having a retardation film, and laminating the vertical alignment type liquid crystal cell by a roll-to-panel manufacturing method.

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