JP2006091369A - Polarizing plate and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate which hardly causes film thickness variations of a polarizer, even of a large area polarizer, and to provide a liquid crystal display device which hardly causes unevenness in brightness by using the polarizing plate. <P>SOLUTION: The roll-shaped polarizing plate is manufactured by sticking a protective film to at least a half side of the polarizer consisting of polyvinyl alcohol of polymerization degree of 1,000 to 3,800, where the range between the maximum film thickness and the minimum film thickness in the width direction of the polarizer is 0 to 3 μm. The liquid crystal display is fabricated, by using the polarizing plate cut out of the roll-shaped polarizing plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a roll-shaped polarizing plate with small thickness unevenness in the width direction of a polarizer and a liquid crystal display device using the polarizing plate.

Liquid crystal display devices are widely used in monitors for personal computers and portable devices, and for television applications because of their various advantages, such as low voltage and low power consumption, enabling miniaturization and thinning. Various modes have been proposed for such a liquid crystal display device depending on the alignment state of the liquid crystal molecules in the liquid crystal cell. Conventionally, the liquid crystal display device is in an alignment state twisted by about 90 ° from the lower substrate to the upper substrate of the liquid crystal cell. The TN mode was mainstream.
In general, a liquid crystal display device includes a liquid crystal cell, an optical compensation sheet, and a polarizer. The optical compensation sheet is used for eliminating image coloring or expanding the viewing angle, and a stretched birefringent film or a film obtained by applying a liquid crystal to a transparent film is used. For example, Patent Document 1 discloses a technique of applying an optical compensation sheet in which a discotic liquid crystal is applied on a triacetyl cellulose film, aligned, and fixed to a TN mode liquid crystal cell to widen the viewing angle. However, a television-use liquid crystal display device that is expected to be viewed from various angles on a large screen has a strict requirement for viewing angle dependency, and even with the above-described method, the requirement cannot be satisfied. For this reason, liquid crystal display devices different from the TN mode, such as an IPS (In-Plane Switching) mode, an OCB (Optically Compensatory Bend) mode, and a VA (Vertically Aligned) mode, have been studied. In particular, the VA mode is attracting attention as a liquid crystal display device for TV because of its high contrast and relatively high production yield.

In general, polyvinyl alcohol (hereinafter referred to as PVA) is mainly used as a polarizer material indispensable for a liquid crystal display device. A polarizer is formed by stretching after dyeing and further crosslinking with a boron compound.
In addition, the cellulose acylate film is characterized by high optical isotropy (low retardation value) compared to other polymer films. Therefore, it is common to use a cellulose acylate film for applications that require optical isotropy, such as a protective film for polarizing plates.
On the other hand, the optical compensation sheet (retardation film) of the liquid crystal display device is required to have optical anisotropy (high retardation value). In particular, an optical compensation sheet for VA requires a front retardation (Re) of 30 to 200 nm and a thickness direction retardation (Rth) of 70 to 400 nm. Therefore, it is common to use a synthetic polymer film having a high retardation value such as a polycarbonate film or a polysulfone film as the optical compensation sheet.
As described above, in the technical field of optical materials, when a polymer film requires optical anisotropy (high retardation value), a synthetic polymer film is used and optical isotropy (low retardation value) is used. It was a general principle to use cellulose acylate films when required.

Patent Document 2 proposes a cellulose acetate film having a high retardation value that can be used for applications requiring optical anisotropy, overcoming the conventional general principle. In this proposal, in order to achieve a high retardation value with cellulose triacetate, an aromatic compound having at least two aromatic rings, particularly a compound having a 1,3,5-triazine ring, is added and subjected to stretching treatment. Cellulose triacetate is generally a polymer material that is difficult to stretch, and it is known that it is difficult to increase the birefringence. To achieve a high retardation value. Since this film can also serve as a protective film for the polarizing plate, there is an advantage that an inexpensive and thin liquid crystal display device can be provided.
Patent Document 3 has an acyl group having 2 to 4 carbon atoms as a substituent, where the substitution degree of acetyl group is A and the substitution degree of propionyl group or butyryl group is B, formula 2.0 ≦ A + B ≦ 3.0 and an optical film containing cellulose ester satisfying the formula A <2.4 at the same time, and the refractive index Nx in the slow axis direction and the refractive index Ny in the fast axis direction at a wavelength of 590 nm are expressed by the formula 0. An optical film characterized by satisfying 0005 ≦ Nx−Ny ≦ 0.0050 is disclosed.
In Patent Document 4, a polarizing plate used in a VA mode liquid crystal display device, the polarizing plate has a polarizer and an optically biaxial mixed fatty acid cellulose ester film, and the liquid crystal cell and the polarizer are interposed. A polarizing plate is disclosed in which the optically biaxial mixed fatty acid cellulose ester film is disposed.
On the other hand, in Patent Document 5, there is a method for producing a polarizing plate with small film thickness unevenness by adjusting the linear pressure during stretching of the raw film and the linear pressure after laminating a protective film on the polarizing film or afterwards. It is disclosed.

Japanese Patent No. 2587398 European Patent Application No. 91656 JP 2002-71957 A JP 2003-270442 A Japanese Patent Laid-Open No. 10-68821

The methods disclosed in Patent Documents 1 to 4 described above are effective in that an inexpensive and thin liquid crystal display device can be obtained. However, in recent years, liquid crystal display devices have been rapidly used for televisions. A television has a brighter backlight than a monitor and can easily see unevenness. In particular, when it is used for a large-sized television, a uniform surface shape with a large area is required. Therefore, the polarizing plate to be used is required to have a large area, little unevenness, and uniform quality.
In the TN mode, which has been the mainstream in the past, the polarizing plate has an absorption axis inclined by 45 ° with respect to the side of the liquid crystal panel, but in the VA mode and IPS mode, the polarizing plate has an absorption axis that is liquid crystal. Since the bonding is performed at 0 ° or 90 ° with respect to the side of the panel, the yield of the polarizing plate is high and a sample can be taken without waste. Therefore, it will be used to the circumference | surroundings of the polarizing plate which was not used conventionally, and the influence of the film thickness difference of a polarizing plate comes to be observed more clearly, and has become a problem.
However, since the present polarizing plate is usually uniaxially stretched in the longitudinal direction, the film thickness difference in the width direction tends to increase. This is because the free uniaxial stretching causes a neck-in phenomenon at the time of stretching, and the film thickness on the end side tends to be thicker than the center part. In this case, the film thickness gradually decreases from one end portion to the central portion, and gradually increases from the other end portion. When the thickness of the polarizer is different, performance such as transmittance is different. Therefore, when such a polarizing plate is used for a large-sized liquid crystal display device, portions having different brightness are formed in the same screen, which is not preferable.
Therefore, development of a polarizing plate with such a small film thickness difference is desired. Patent Document 5 discloses a method for producing a polarizing plate with small film thickness unevenness, but is limited to the case where the polymerization degree of PVA is 4000 or more. (Highly polymerized PVA film has the disadvantage that uniform stretching is difficult and it is difficult to obtain a uniformly dyed polarizer without uneven dyeing.) Further, the protective film of the polarizing plate has a small Re value and Rth value. The optical compensation effect was small.
An object of the present invention is to provide a polarizing plate excellent in optical compensation performance that maintains uniform quality even in a large area, and a liquid crystal display device using the polarizing plate.

As a result of intensive studies by the present inventors, it has been found that the above object can be achieved by using a polarizer having a small thickness difference in the width direction, and the present invention has been completed.
That is, the present invention is a polarizing plate and a liquid crystal display device having the following constitutions, thereby achieving the object of the present invention.
(1) A roll-shaped polarizing plate in which a protective film is bonded to at least one side of a polarizer made of polyvinyl alcohol having a polymerization degree of 1000 to 3800, and the difference between the maximum film thickness and the minimum film thickness in the width direction of the polarizer. A roll-shaped polarizing plate characterized by having a thickness of 0 to 3 μm.
(2) The roll-shaped polarizing plate according to (1), wherein a film thickness difference between 1 cm in the width direction of the polarizer is 0.25 μm / cm or less.
(3) The roll-shaped polarizing plate according to (1) or (2), wherein the total width is 400 mm to 3000 mm.
(4) The front retardation value Re _{(590) at a} wavelength of 590 nm and the retardation value Rth ₍₅₉₀₎ in the film thickness direction at a wavelength of 590 nm of the protective film on one side satisfy the following formulas (I) and (II). The roll-shaped polarizing plate according to any one of (1) to (3).
Formula (I): 20 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm
Formula (II): 70 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm
(5) The ratio of the Re ₍₅₉₀₎ value to the Rth ₍₅₉₀₎ value (Re / Rth ratio) of the protective film on one side is 0.1 to 0.8 ( The roll-shaped polarizing plate according to any one of 1) to (4).
(6) A cellulose acylate film comprising, as a main polymer component, a cellulose acylate in which the protective film on one side is a mixed fatty acid ester of cellulose in which a hydroxyl group of cellulose is substituted with an acetyl group and an acyl group having 3 or more carbon atoms Because
The cellulose acylate is characterized in that the substitution degree A of the acetyl group and the substitution degree B of the acyl group having 3 or more carbon atoms satisfy the following formulas (III) and (IV): 5) The roll-shaped polarizing plate in any one of.
Formula (III): 2.0 ≦ A + B ≦ 3.0
Formula (IV): 0 <B
(7) The roll-shaped polarizing plate according to (6), wherein the acyl group having 3 or more carbon atoms is a butanoyl group.
(8) The roll polarizing plate as described in (6), wherein the acyl group having 3 or more carbon atoms is a propionyl group.
(9) The glucose comprising the cellulose, wherein the protective film on one side is a film composed of cellulose acylate obtained by substituting the hydroxyl group of glucose units constituting cellulose with an acyl group having 2 or more carbon atoms. When the substitution degree of the hydroxyl group at the 2-position of the unit with an acyl group is DS2, the substitution degree of the hydroxyl group at the 3-position with an acyl group is DS3, and the substitution degree of the hydroxyl group at the 6-position with DS6 is DS6, the following formula (V) And a roll-type polarizing plate according to any one of (1) to (8), which is a cellulose acylate film satisfying (VI).
Formula (V): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
Formula (VI): DS6 / (DS2 + DS3 + DS6) ≧ 0.315
(10) The roll polarizing plate according to (9), wherein the acyl group is an acetyl group.
(11) Any one of (1) to (10), wherein the protective film on one side contains at least one of a plasticizer, an ultraviolet absorber, a peeling accelerator, a dye, and a matting agent. The roll-shaped polarizing plate of crab.
(12) The roll-shaped polarized light according to any one of (1) to (11), wherein the protective film on one side contains at least one rod-like compound or discotic compound retardation developer. Board.
(13) The roll-shaped polarizing plate according to any one of (1) to (11), wherein the protective film on one side is provided with an optically anisotropic layer on a polymer film.
(14) (1) to (13), wherein at least one of a hard coat layer, an antiglare layer, and an antireflection layer is provided on the surface of the protective film disposed on the side opposite to the protective film on one side. The roll-shaped polarizing plate in any one.
(15) The roll-shaped polarizing plate according to any one of (1) to (14), wherein a retardation film is bonded to the one protective film side using an adhesive.
(16) A polarizing plate cut out from the roll-shaped polarizing plate according to any one of (1) to (15).
(17) A liquid crystal display device using the polarizing plate according to (16) so that the protective film on one side is disposed on the liquid crystal cell side.

  The roll-shaped polarizing plate of the present invention has a small thickness difference between the polarizers, and by using the polarizing plate of the present invention, a liquid crystal display device having a uniform display quality even on a large screen can be produced.

  Hereinafter, the present invention will be described in more detail. In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”. . Moreover, in this specification, description with "(meth) acrylate" represents the meaning of "at least one of an acrylate and a methacrylate." The same applies to “(meth) acrylic acid” and the like.

(Polarizer)
First, the polarizing plate of this invention is demonstrated.

  The polarizing plate of the present invention is a roll-shaped polarizing plate in which a protective film is bonded to at least one side of a polarizer made of polyvinyl alcohol having a polymerization degree of 1000 to 3800, and has a maximum thickness and a minimum thickness in the width direction of the polarizer. A roll-shaped polarizing plate having a difference in film thickness of 0 to 3 μm, and a polarizing plate cut out from the roll-shaped polarizing plate. (Hereinafter, in this specification, “roll-shaped polarizing plate” is also simply referred to as “polarizing plate”.)

The polarizing plate of the present invention preferably uses at least one optical cellulose acylate film relating to the present invention described later as a protective film for the polarizer.
The polarizing plate is usually composed of a polarizer and two transparent protective films disposed on both sides thereof. And in this invention, Preferably the cellulose acylate film regarding this invention mentioned later is used as at least one protective film. The other protective film may be a cellulose acylate film according to the present invention or a normal cellulose acetate film. In the present invention, by reducing the film thickness difference in the width direction of the polarizer, uniform display quality is realized even when used as a large liquid crystal display device.

Polarizers for polarizing plates include iodine-based polarizers, dye-based polarizers using dichroic dyes, and polyene-based polarizers. The iodine polarizer and the dye polarizer are generally produced using a polyvinyl alcohol film.
The polarizer relating to the polarizing plate of the present invention is preferably composed of polyvinyl alcohol (PVA) and a dichroic molecule.
PVA is a polymer material obtained by saponifying polyvinyl acetate, but may contain components copolymerizable with vinyl acetate such as unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, and vinyl ethers. . In addition, modified PVA containing an acetoacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group, or the like can also be used.

The saponification degree of PVA is not particularly limited, but is preferably 80 to 100 mol%, particularly preferably 90 to 100 mol% from the viewpoint of solubility and the like. Moreover, 1000-3800 are preferable and, as for the polymerization degree of PVA, 1500-3800 are especially preferable.
The syndiotacticity of PVA is preferably 55% or more for improving durability as described in Japanese Patent No. 2978219, but 45 to 52.5% described in Japanese Patent No. 3317494 is also preferable. Can be used.

After PVA is formed into a film, it is preferable to introduce a dichroic molecule to constitute a polarizer. As a method for producing a PVA film, a method of forming a film by casting a stock solution in which a PVA resin is dissolved in water or an organic solvent is generally preferably used. The concentration of the polyvinyl alcohol-based resin in the stock solution is usually 5 to 20% by mass, and a PVA film having a thickness of 10 to 200 μm can be produced by forming this stock solution by casting. The PVA film can be produced with reference to Japanese Patent No. 3342516, Japanese Patent Laid-Open No. 9-328593, Japanese Patent Laid-Open No. 13-302817, and Japanese Patent Laid-Open No. 14-144401.
The crystallinity of the PVA film is not particularly limited. However, in order to reduce the average crystallinity (Xc) of 50 to 75% by mass and the in-plane hue variation described in Japanese Patent No. 3251073, Japanese Patent Application Laid-Open No. Hei 14 A PVA film having a crystallinity of 38% or less described in Japanese Patent No. -236214 can be used.
The birefringence (Δn) of the PVA film is preferably small, and a PVA film having a birefringence of 1.0 × 10 ⁻³ or less described in Japanese Patent No. 3342516 can be preferably used. However, as described in JP-A-14-228835, the birefringence of the PVA film is set to 0.02 or more and 0.01 or less in order to obtain a high degree of polarization while avoiding cutting during stretching of the PVA film. Alternatively, the value of (nx + ny) / 2-nz may be set to 0.0003 or more and 0.01 or less as described in JP-A-14-60505. The retardation (in-plane) of the PVA film is preferably from 0 nm to 100 nm, and more preferably from 0 nm to 50 nm. Moreover, 0 nm or more and 500 nm or less are preferable, and, as for Rth (film thickness direction) of a PVA film, 0 nm or more and 300 nm or less are more preferable.
In addition, the polarizing plate of the present invention has a PVA film having a 1,2-glycol bond amount of 1.5 mol% or less, which is described in Japanese Patent No. 3021494, and Japanese Patent Laid-Open No. 13-316492. PVA film having 500 μm or less of optical foreign matters of 5 μm or more per 100 cm ² , and PVA having hot water cutting temperature spots in the TD direction of 1.5 ° C. or less of the film described in JP-A-14-30163 It is manufactured from a solution in which 1 to 100 parts by mass of a trivalent or 6-valent polyhydric alcohol such as glycerin or a plasticizer described in JP-A-6-289225 is mixed. A filmed PVA film can be preferably used.
Although the film thickness before extending | stretching of a PVA film is not specifically limited, 1 micrometers-1 mm are preferable and 20-200 micrometers is especially preferable from a viewpoint of stability of film holding | maintenance and the uniformity of extending | stretching. As described in JP-A No. 14-236212, a thin PVA film may be used in which the stress generated when stretching from 4 to 6 times in water is 10 N or less.

Dichroic molecule I ₃ ^- or I ₅ ^- can be preferably used an iodine ion or a dichroic dye higher such. In the present invention, higher-order iodine ions are particularly preferably used. Higher-order iodine ions are dissolved in potassium iodide aqueous solution as described in Nagata Ryo, “Application of Polarizer”, CMC Publishing and Industrial Materials, Vol. 28, No. 7, p39-p45. The PVA can be immersed in the prepared liquid and / or boric acid aqueous solution and adsorbed and oriented in the PVA.
When a dichroic dye is used as the dichroic molecule, an azo dye is preferable, and a bisazo dye and a trisazo dye are particularly preferable. The dichroic dye is preferably a water-soluble dye. For this reason, a hydrophilic substituent such as a sulfonic acid group, an amino group or a hydroxyl group is introduced into the dichroic molecule, so that a free acid, an alkali metal salt, an ammonium salt or an amine is introduced. It is preferably used as a salt.
Specific examples of such dichroic dyes include C.I. I. Direct Red 37, Congo Red (C.I. Direct Red 28), C.I. I. Direct Violet 12, C.I. I. Direct Blue 90, C.I. I. Direct Blue 22, C.I. I. Direct Blue 1, C.I. I. Direct Blue 151, C.I. I. Benzidines such as Direct Green 1, C.I. I. Direct Yellow 44, C.I. I. Direct Red 23, C.I. I. Diphenylurea such as Direct Red 79, C.I. I. Stilbene series such as Direct Yellow 12, C.I. I. Dinaphthylamine type such as Direct Red 31, C.I. I. Direct Red 81, C.I. I. Direct Violet 9, C.I. I. Mention may be made of J acid systems such as Direct Blue 78.
In addition, C.I. I. Direct Yellow 8, C.I. I. Direct Yellow 28, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 87, C.I. I. Direct Yellow 142, C.I. I. Direct Orange 26, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Orange 106, C.I. I. Direct Orange 107, C.I. I. Direct Red 2, C.I. I. Direct Red 39, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Direct Red 240, C.I. I. Direct Red 242, C.I. I. Direct Red 247, C.I. I. Direct Violet 48, C.I. I. Direct Violet 51, C.I. I. Direct Violet 98, C.I. I. Direct Blue 15, C.I. I. Direct Blue 67, C.I. I. Direct Blue 71, C.I. I. Direct Blue 98, C.I. I. Direct Blue 168, C.I. I. Direct Blue 202, C.I. I. Direct Blue 236, C.I. I. Direct Blue 249, C.I. I. Direct Blue 270, C.I. I. Direct Green 59, C.I. I. Direct Green 85, C.I. I. Direct Brown 44, C.I. I. Direct Brown 106, C.I. I. Direct Brown 195, C.I. I. Direct Brown 210, C.I. I. Direct Brown 223, C.I. I. Direct Brown 224, C.I. I. Direct Black 1, C.I. I. Direct Black 17, C.I. I. Direct Black 19, C.I. I. Direct Black 54 and the like are further disclosed in JP-A-62-70802, JP-A-1-161202, JP-A-1-172906, JP-A-1-172907, JP-A-1-183602, JP-A-1-248105, The dichroic dyes described in JP-A-1-265205 and JP-A-7-261024 can also be preferably used. In order to produce dichroic molecules having various hues, two or more of these dichroic dyes may be blended. When a dichroic dye is used, the adsorption thickness may be 4 μm or more as described in JP-A No. 14-82222.
If the content of the dichroic molecule in the film is too small, the degree of polarization is low, and if it is too large, the single-plate transmittance is lowered. Therefore, the polyvinyl alcohol polymer constituting the film matrix is usually used. On the other hand, it is adjusted to a range of 0.01% by mass to 5% by mass.

  The polarizing plate of this invention may have an adhesive layer, a separate film, and a protective film as a component other than the above-mentioned polarizer and protective film.

Next, the manufacturing process of the polarizing plate of this invention is demonstrated.
The manufacturing process of the polarizing plate in the present invention is preferably composed of a swelling process, a dyeing process, a hardening process, a stretching process, a drying process, a protective film bonding process, and a post-bonding drying process. The order of the dyeing step, the hardening step, and the stretching step may be arbitrarily changed, or several steps may be combined and performed simultaneously. Further, as described in Japanese Patent No. 3331615, washing with water after the hardening step can be preferably performed.

  In the present invention, it is particularly preferable to sequentially perform the swelling step, the dyeing step, the hardening / stretching step, the drying step, the protective film bonding step, and the post-bonding drying step in the order described. An on-line surface inspection step may be provided during or after the above-described steps.

The swelling step is preferably performed only with water, but as described in JP-A-10-153709, for the purpose of stabilizing optical performance and avoiding wrinkling of the polarizing plate substrate in the production line. It is also possible to manage the degree of swelling of the polarizing plate substrate by swelling the polarizing plate substrate with an aqueous boric acid solution.
Moreover, although the temperature and time of a swelling process can be defined arbitrarily, 10 to 60 degreeC and 5 to 2000 second are preferable.

For the dyeing step, the method described in JP-A-2002-86554 can be used. Further, as a dyeing method, not only immersion but any means such as application or spraying of iodine or a dye solution can be used. Further, as described in JP-A No. 13-290025, a method of dyeing while stirring the iodine concentration, the dyeing bath temperature, the draw ratio in the bath, and the bath liquid in the bath may be used.
When higher-order iodine ions are used as the dichroic molecule, in order to obtain a high-contrast polarizing plate, it is preferable to use a solution obtained by dissolving iodine in an aqueous potassium iodide solution in the dyeing step. In this case, iodine in the iodine-potassium iodide aqueous solution is preferably 0.05 to 20 g / l, potassium iodide is 3 to 200 g / l, and the mass ratio of iodine and potassium iodide is preferably 1 to 2000. The dyeing time is preferably 10 to 1200 seconds, and the liquid temperature is preferably 10 to 60 ° C. More preferably, iodine is 0.5 to 2 g / l, potassium iodide is 30 to 120 g / l, the mass ratio of iodine and potassium iodide is 30 to 120, dyeing time is 30 to 600 seconds, and liquid temperature is 20-50 degreeC is good.
Further, as described in Japanese Patent No. 3145747, boron compounds such as boric acid and borax may be added to the dyeing solution.

In the hardening step, it is preferable to immerse in the crosslinking agent solution or apply the solution to contain the crosslinking agent. Further, as described in JP-A-11-52130, the hardening process can be performed in several steps.
As the crosslinking agent, those described in US Reissued Patent No. 232897 can be used. As described in Japanese Patent No. 3357109, a polyvalent aldehyde is used as a crosslinking agent in order to improve dimensional stability. Although it can be used, boric acids are most preferably used.
When boric acid is used as a crosslinking agent used in the hardening step, metal ions may be added to the boric acid-potassium iodide aqueous solution. Zinc chloride is preferable as the metal ion. However, as described in JP-A No. 2000-35512, zinc halide such as zinc iodide, zinc sulfate such as zinc acetate is used instead of zinc chloride. It can also be used.
In the present invention, it is preferable to prepare a boric acid-potassium iodide aqueous solution to which zinc chloride has been added, and perform dura- tion by immersing the PVA film. Boric acid is preferably 1 to 100 g / l, potassium iodide is 1 to 120 g / l, zinc chloride is preferably 0.01 to 10 g / l, hardening time is preferably 10 to 1200 seconds, and liquid temperature is preferably 10 to 60 ° C. . More preferably, boric acid is 10 to 80 g / l, potassium iodide is 5 to 100 g / l, zinc chloride is 0.02 to 8 g / l, hardening time is 30 to 600 seconds, and liquid temperature is 20 to 50 ° C is preferable.

  The stretching step preferably uses a longitudinal uniaxial stretching method as described in US Pat. No. 2,454,515 or the like, or a tenter method as described in JP-A-2002-86554. Can do. A preferable draw ratio is 2 times or more and 12 times or less, and more preferably 3 times or more and 10 times or less. Further, the relationship between the draw ratio, the original fabric thickness, and the polarizer thickness is described in JP-A No. 14-040256 (polarizer film thickness after protective film bonding / original fabric film thickness) × (total draw ratio) )> 0.17, or the relationship between the width of the polarizer when leaving the final bath and the width of the polarizer when bonding the protective film is 0.80 ≦ (protection) described in JP-A-14-040247 It is also preferable to set the polarizer width at the time of film bonding / the width of the polarizer when leaving the final bath) ≦ 0.95.

A preferable film thickness of the polarizer is preferably 5 μm to 40 μm, and more preferably 10 μm to 37 μm. The ratio between the thickness of the polarizer and the thickness of the protective film described later is 0.01 ≦ A (polarizer film thickness) / B (protective film thickness) ≦ 0.16 described in JP-A No. 14-174727. It is also preferable to set the range.
The film thickness difference in the width direction of the polarizer is preferably 3 μm or less, and more preferably 2 μm or less. When the thickness of the polarizer is large, the transmittance decreases. For this reason, if the difference in the polarizer film thickness in the width direction is large, it becomes a polarizing plate having a significantly different transmittance in the width direction, and when used in a liquid crystal display device, a bright part and a dark part occur on the same screen. End up. As a result of experiments by the present inventors, it has been found that there is the following relationship between the polarizer film thickness difference and the screen uniformity. If the thickness difference of the polarizer is larger than 3 μm, the screen uniformity is deteriorated, which is not preferable.

Polarizer film thickness difference Screen uniformity ―――――――――――――
0μm ◎
1μm ◎
2μm ◎
3μm ○
4μm ×
5μm ×
6μm XX

[Screen uniformity evaluation]
A: Every part of the screen has uniform brightness, and the uniformity is very good.
○: On the screen, if you look closely, you can see a place that looks slightly dark.
×: There is a dark part on the screen.
XX: A clearly dark part is recognized on the screen.

  Moreover, it is also preferable that the maximum value of the film thickness difference between 1 cm in the width direction of the polarizer is 0.25 μm / cm or less. If there is a difference of 0.25 μm / cm or more, the transmittance varies rapidly, so that the contrast on the screen becomes conspicuous, which is not preferable.

As a method for producing a polarizing plate having a small difference in the thickness of the polarizer in the width direction as in the present invention, a method of preheating by applying a temperature gradient in the width direction of the PVA film or a stretching step is fixed before the stretching step. A method of stretching, biaxial stretching, or the like is conceivable.
Preheating by applying a temperature gradient in the width direction of the PVA film before the stretching step is to heat the end portion where the polarizer film thickness becomes thick before stretching, thereby making the end portion soft and easy to stretch. There is an effect, and the influence of neck-in can be reduced.
Also, fixed width stretching means stretching while holding the ear end using a pinch guider, cross guider, tenter clip, expander roll, spiral roll, etc., and shrinking in the width direction of the ear end. It can be stretched while preventing.
Biaxial stretching means stretching in two directions, the longitudinal direction and the transverse direction, and may be simultaneous biaxial stretching or sequential biaxial stretching. In the case of biaxial stretching, the longitudinal direction is preferably 2 to 12 times, preferably 3 to 10 times, and the width direction is preferably transversely stretched in the range of 1 to 2 times.

  In the present invention, the width direction of the polarizing plate means a direction orthogonal to the stretching direction (conveying direction) of the polarizer. The total width of the roll-shaped polarizing plate is preferably 400 mm to 3000 mm, more preferably 600 mm to 2000 mm, and still more preferably 800 mm to 1600 mm. When the total width of the roll-shaped polarizing plate is 400 mm or less, large-size cutting cannot be performed, and when it is 3000 mm or more, it is difficult to hold and the manufacturing aptitude is lacking.

  As the drying step, a method known in JP-A-2002-86554 can be used, but a preferable temperature range is 30 ° C. to 100 ° C., and a preferable drying time is 30 seconds to 60 minutes. Further, as described in Japanese Patent No. 3148513, heat treatment is performed so that the fading temperature in water is 50 ° C. or higher, or described in Japanese Patent Laid-Open Nos. 7-325215 and 7-325218. As described above, aging in an atmosphere in which the temperature and humidity are controlled can be preferably performed.

  The protective film laminating step is a step of laminating both surfaces of the above-described polarizer that has gone through the drying step with two protective films. A method of bonding with a pair of rolls is preferably used so that the adhesive liquid is supplied immediately before bonding and the polarizer and the protective film are overlapped. Further, as described in JP-A-2001-296426 and JP-A-2002-86554, in order to suppress the groove-like unevenness of the record due to the stretching of the polarizer, It is preferable to adjust the moisture content. In the present invention, a moisture content of 0.1% to 30% is preferably used.

  The adhesive between the polarizer and the protective film is not particularly limited, and examples thereof include PVA resins (including modified PVA such as acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group) and boron compound aqueous solution. PVA resin is preferable. The thickness of the adhesive layer is preferably 0.01 to 5 μm after drying, and particularly preferably 0.05 to 3 μm.

  Moreover, in order to improve the adhesive force of a polarizer and a protective film, it is preferable to perform adhesion after surface-treating the protective film to make it hydrophilic. The surface treatment method is not particularly limited, and a known method such as a saponification method using an alkaline solution or a corona treatment method can be used. Further, an easy-adhesion layer such as a gelatin undercoat layer may be provided after the surface treatment. As described in JP-A No. 14-267839, the contact angle of the protective film surface with water is preferably 50 ° or less.

  The drying conditions after bonding are in accordance with the method described in JP-A-2002-86554, but a preferable temperature range is 30 ° C. to 100 ° C., and a preferable drying time is 30 seconds to 60 minutes. It is also preferable to perform aging in an atmosphere with temperature and humidity control as described in JP-A-7-325220.

The element content in the polarizer is as follows: iodine 0.1-3.0 g / m ² , boron 0.1-5.0 g / m ² , potassium 0.1-2.0 g / m ² , zinc 0-2. It is preferably 0 g / m ² . Further, the potassium content may be 0.2% by mass or less as described in JP-A No. 13-166143, and the zinc content in the polarizer is described in JP-A No. 12-35512. It is good also as 0.04 mass%-0.5 mass% currently being carried out.

  As described in Japanese Patent No. 3323255, in order to increase the dimensional stability of the polarizing plate, an organic titanium compound and / or an organic zirconium compound is added in any of the dyeing process, the stretching process, and the hardening process. It is also possible to use and contain at least one compound selected from organic titanium compounds and organic zirconium compounds. A dichroic dye may be added to adjust the hue of the polarizing plate.

  From the roll-shaped polarizing plate obtained as described above, for example, it can be cut into an appropriate size according to a liquid crystal display panel or the like. Particularly in the VA mode or IPS mode polarizing plate, the polarizing plate is cut out in parallel because the polarizing plate side is cut out in parallel because the polarizing plate has an absorption axis of 0 ° or 90 ° with respect to the side of the liquid crystal panel. The yield is high and samples can be taken without waste, and it is possible to use even surroundings that were not used conventionally.

(Cellulose acylate film)
Next, the cellulose acylate used in the present invention will be described in detail. In the present invention, two or more different cellulose acylates may be mixed and used.
The cellulose acylate is a mixed fatty acid ester of cellulose obtained by substituting a hydroxyl group of cellulose with an acetyl group and an acyl group having 3 or more carbon atoms, and the degree of substitution of the cellulose with a hydroxyl group is represented by the following formula ( Cellulose acylate satisfying III) and (IV).
Formula (III): 2.0 ≦ A + B ≦ 3.0
Formula (IV): 0 <B
Here, A and B in the formula represent the substitution degree of the acyl group substituted with the hydroxyl group of cellulose, A is the substitution degree of the acetyl group, and B is the substitution degree of the acyl group having 3 or more carbon atoms.
Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by esterifying some or all of these hydroxyl groups with acyl groups. The degree of acyl substitution means the proportion of cellulose esterified at each of the 2-position, 3-position and 6-position (100% esterification has a substitution degree of 1).

In the present invention, the total substitution degree (A + B) of hydroxyl groups A and B is 2.0 to 3.0, preferably 2.2 to 2.9, as shown in the above formula (III). And particularly preferably 2.40 to 2.85. Further, the substitution degree of B is preferably larger than 0, more preferably 0.6 or more, as shown in the above formula (IV).
When A + B is less than 2.0, the hydrophilicity becomes strong and it is easy to be affected by environmental humidity.
Further, 28% or more of B is preferably a 6-position hydroxyl group substituent, more preferably 30% or more is a 6-position hydroxyl group substituent, more preferably 31% or more, and particularly preferably 32% or more. A substituent at the 6-position hydroxyl group is preferred.
Furthermore, the total substitution degree of A and B at the 6-position of cellulose acylate is preferably 0.75 or more, more preferably 0.80 or more, and particularly preferably 0.85 or more. With these cellulose acylate films, a solution for preparing a film having preferable solubility and filterability can be produced, and a good solution can be produced even in a non-chlorine organic solvent. Furthermore, it becomes possible to produce a solution having a low viscosity and good filterability.

Further, when the cellulose acylate film is a protective film disposed on the liquid crystal cell side of the polarizing plate, the substitution degree of the hydroxyl group at the 2-position of the glucose unit constituting the cellulose by the acyl group is DS2, and the acyl group of the hydroxyl group at the 3-position It is preferable to satisfy the following formulas (V) and (VI) where DS3 is the degree of substitution by DS3 and DS6 is the degree of substitution of the hydroxyl group at the 6-position.
Formula (V): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
Formula (VI): DS6 / (DS2 + DS3 + DS6) ≧ 0.315
By satisfying the above formulas (V) and (VI), it is easy to adjust the optical performance within a preferable range, which is preferable.

  The acyl group having 3 or more carbon atoms may be an aliphatic group or an aromatic hydrocarbon group, and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred acyl groups having 3 or more carbon atoms include propionyl, butanoyl, keptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl Oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl group and the like. Among these, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl group and the like are preferable. Particularly preferred are propionyl and butanoyl groups. In the case of a propionyl group, the substitution degree B is preferably 1.3 or more.

  Specific examples of the mixed fatty acid cellulose acylate include cellulose acetate propionate and cellulose acetate butyrate.

(Method for synthesizing cellulose acylate)
The basic principle of the cellulose acylate synthesis method is described in Mita et al., Wood chemistry, 180-190 (Kyoritsu Shuppan, 1968). A typical synthesis method is a liquid phase acetylation method using a carboxylic acid anhydride-acetic acid-sulfuric acid catalyst.
In order to obtain the cellulose acylate, specifically, a cellulose raw material such as cotton linter or wood pulp is pretreated with an appropriate amount of acetic acid, and then esterified by introducing it into a pre-cooled carboxylated mixed solution. Synthesize the rate (total of acyl substitutions at the 2nd, 3rd and 6th positions is approximately 3.00). The carboxylated mixed solution generally contains acetic acid as a solvent, carboxylic anhydride as an esterifying agent, and sulfuric acid as a catalyst. The carboxylic anhydride is usually used in a stoichiometric excess over the sum of the cellulose that reacts with it and the water present in the system. After completion of the esterification reaction, a neutralizing agent (for example, calcium, magnesium, iron, aluminum or zinc) is used for hydrolysis of excess carboxylic anhydride remaining in the system and neutralization of a part of the esterification catalyst. Of carbonate, acetate or oxide). Next, the obtained complete cellulose acylate is saponified and aged by maintaining it at 50 to 90 ° C. in the presence of a small amount of an acetylation reaction catalyst (generally, remaining sulfuric acid) to obtain the desired degree of acyl substitution and polymerization. The cellulose acylate having a degree is changed. When the desired cellulose acylate is obtained, the catalyst remaining in the system is completely neutralized with the neutralizing agent as described above, or in water or dilute sulfuric acid without neutralization. The cellulose acylate solution is added (or water or dilute sulfuric acid is added to the cellulose acylate solution), the cellulose acylate is separated, washed and stabilized, and the like. Can be obtained.

In the cellulose acylate film, it is preferable that the polymer component constituting the film is substantially composed of the specific cellulose acylate. “Substantially” means 55% by mass or more (preferably 70% by mass or more, more preferably 80% by mass or more) of the polymer component.
The cellulose acylate is preferably used in the form of particles. 90% by mass or more of the particles to be used preferably have a particle diameter of 0.5 to 5 mm. Moreover, it is preferable that 50 mass% or more of the particle | grains to be used have a particle diameter of 1-4 mm. The cellulose acylate particles preferably have a shape as close to a sphere as possible.
The degree of polymerization of cellulose acylate preferably used in the present invention is a viscosity average degree of polymerization, preferably 200 to 700, more preferably 250 to 550, still more preferably 250 to 400, and particularly preferably 250 to 350. . The average degree of polymerization can be measured by the intrinsic viscosity method of Uda et al. (Kazuo Uda, Hideo Saito, Journal of Textile Society, 1962, Vol. Further details are described in JP-A-9-95538.

When the low molecular component is removed, the average molecular weight (polymerization degree) is increased, but the viscosity is lower than that of ordinary cellulose acylate. Therefore, the cellulose acylate from which the low molecular component is removed is useful. . Cellulose acylate having a small amount of low molecular components can be obtained by removing low molecular components from cellulose acylate synthesized by a usual method. The removal of the low molecular component can be carried out by washing the cellulose acylate with an appropriate organic solvent. In addition, when manufacturing a cellulose acylate with few low molecular components, it is preferable to adjust the sulfuric acid catalyst amount in an acetylation reaction to 0.5-25 mass parts with respect to 100 mass parts of cellulose acylates. When the amount of the sulfuric acid catalyst is in the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized. When used in the production of cellulose acylate, the water content is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly 0.7% by mass or less. In general, cellulose acylate contains water and is known to have a water content of 2.5 to 5% by mass. In order to obtain the water content of the cellulose acylate in the present invention, it is necessary to dry it, and the method is not particularly limited as long as the desired water content is obtained.
The cellulose acylate raw material cotton and the synthesis method thereof are disclosed in JIII Journal of Technical Disclosure No. 2001-1745 (issued March 15, 2001, Invention Association) p. Raw material cotton and synthesis methods described in detail in 7-12 can be employed.

  The cellulose acylate film according to the present invention can be obtained by forming a film using a solution obtained by dissolving the specific cellulose acylate and, if necessary, an additive in an organic solvent.

(Additive)
Examples of the additive that can be used in the cellulose acylate solution in the present invention include a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a retardation (optical anisotropy) developing agent, and a retardation (optical anisotropy). Examples thereof include a reducing agent, fine particles, a peeling accelerator, and an infrared absorber. In the present invention, it is preferable to use a retardation developer. Moreover, it is preferable to use at least one of a plasticizer, an ultraviolet absorber and a peeling accelerator.
They may be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, ultraviolet absorbers of 20 ° C. or lower and 20 ° C. or higher can be mixed and used, and plasticizers can also be mixed and used, for example, as described in JP-A No. 2001-151901.
As the ultraviolet absorber, any type can be selected according to the purpose, and a salicylic acid ester-based, benzophenone-based, benzotriazole-based, benzoate-based, cyanoacrylate-based, nickel complex-based absorber or the like is used. Preferred are benzophenone series, benzotriazole series, and salicylic acid ester series. Examples of benzophenone ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4-methoxybenzophenone, 2, 2′-di-hydroxy-4,4′-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4- (2-hydroxy-3- And methacryloxy) propoxybenzophenone. As a benzotriazole ultraviolet absorber, 2 (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-butylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5 Examples include chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, and the like. Examples of salicylic acid esters include phenyl salicylate, p-octylphenyl salicylate, and p-tert-butylphenyl salicylate. Among these exemplified ultraviolet absorbers, in particular, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4,4′-methoxybenzophenone, 2 (2′-hydroxy-3′-tert-butyl- 5'-methylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole is particularly preferred.

  As the ultraviolet absorber, it is preferable to use a combination of a plurality of absorbers having different absorption wavelengths because a high blocking effect can be obtained in a wide wavelength range. From the viewpoint of preventing deterioration of the liquid crystal, the ultraviolet absorbent for liquid crystal is preferably excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less, and from the viewpoint of liquid crystal display properties, the absorption of visible light having a wavelength of 400 nm or more is small. Particularly preferred ultraviolet absorbers are the benzotriazole compounds, benzophenone compounds, and salicylic acid ester compounds mentioned above. Among these, a benzotriazole-based compound is preferable because unnecessary coloring with respect to the cellulose ester is small.

  As for the UV absorber, JP-A-60-235852, JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, JP-A-6-107854. 118233, 6-148430, 7-11056, 7-11055, 7-11056, 8-29619, 8-239509, JP-A-2000-204173 These compounds can also be used.

  0.001-5 mass% is preferable with respect to a cellulose acylate, and, as for the addition amount of a ultraviolet absorber, 0.01-1 mass% is more preferable. If the addition amount is less than 0.001% by mass, the effect of addition cannot be sufficiently exhibited. If the addition amount exceeds 5% by mass, the ultraviolet absorber may bleed out to the film surface.

  Further, the ultraviolet absorber may be added simultaneously with the dissolution of cellulose acylate, or may be added to the dope after dissolution. In particular, a mode in which an ultraviolet absorbent solution is added to the dope immediately before casting using a static mixer or the like is preferable because the spectral absorption characteristics can be easily adjusted.

  The deterioration inhibitor can prevent cellulose triacetate and the like from deteriorating and decomposing. Examples of the deterioration preventing agent include butylamine, hindered amine compounds (JP-A-8-325537), guanidine compounds (JP-A-5-271471), benzotriazole-based UV absorbers (JP-A-6-235819), and benzophenone-based compounds. There are compounds such as UV absorbers (JP-A-6-118233).

The plasticizer is preferably a phosphate ester or a carboxylic acid ester. The plasticizer may be triphenyl phosphate (TPP), tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate (BDP), trioctyl phosphate, tributyl phosphate, dimethyl phthalate (DMP) ), Diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP), diethyl hexyl phthalate (DEHP), triethyl O-acetylcitrate (OACTE), tributyl O-acetylcitrate ( OACTB), acetyl triethyl citrate, acetyl tributyl citrate, butyl oleate, methyl acetyl ricinoleate, dibutyl sebacate, tria Chin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, and more preferably one selected from butyl phthalyl butyl glycolate. Furthermore, the plasticizer is preferably (di) pentaerythritol esters, glycerol esters, diglycerol esters.
Examples of the peeling accelerator include citric acid ethyl esters. Further, infrared absorbers are described in, for example, JP-A-2001-194522.

In the present invention, a dye for adjusting the hue may be added. The content of the dye is preferably 10 to 1000 ppm, more preferably 50 to 500 ppm in terms of a mass ratio with respect to cellulose acylate. By containing the dye in this way, light piping of the cellulose acylate film can be reduced and the yellowness can be improved. These compounds may be added together with cellulose acylate and a solvent during the preparation of the cellulose acylate solution, or may be added during or after the solution preparation. Moreover, you may add to the ultraviolet absorber liquid added in-line.
The dye used in the present invention is preferably a compound represented by the following general formula (I) or (II).
Formula (I)

In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each hydrogen atom, hydroxyl group, aliphatic group, aromatic group, heterocyclic group, halogen atom, cyano, Group, nitro group, COR ⁹ , COOR ⁹ , NR ⁹ R ¹⁰ , NR ¹⁰ COR ¹¹ , NR ¹⁰ SO ₂ R ¹¹ , CONR ⁹ R ¹⁰ , SO ² NR ⁹ R ¹⁰ , COR ¹¹ , SO ² R ¹¹ , OCOR ¹¹ , represents a ^{NR 9 CONR 10 R 11, CONHSO} 2 R 11, SO 2 NHCOR 11, R 9, R 10 are each a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, R ¹¹ is an aliphatic group, R ⁹ and R ¹⁰ may be linked to form a 5- or 6-membered ring, and R ¹ and R ² or R ² and R ³ may be linked to form a ring. It may be formed.
Formula (II)

In the formula, R ²¹ , R ²³ and R ²⁴ are a hydrogen atom, a hydroxyl group, a nitro group, a cyano group, an aliphatic group, an aromatic group, COR ²⁹ , COOR ²⁹ , NR ²⁹ R ³⁰ , NR ³⁰ COR ³¹ , NR ³⁰ SO ₂ represents R ³¹ , R ²² represents an aliphatic group or an aromatic group, R ²⁹ and R ³⁰ have the same meanings as R ⁹ and R ¹⁰ in formula (I), and R ³¹ represents in formula (I) R ¹¹ as synonymous. However, one or more of R ²¹ , R ²² , R ²³ , and R ²⁴ are groups other than hydrogen.

Hereinafter, each group of the general formula (I) will be described in detail. The aliphatic group represented by R ^{1 to} R ¹¹ is an alkyl group having 1 to 20 carbon atoms (for example, methyl, ethyl, n-butyl, isopropyl, 2-ethylhexyl, n-decyl, n-octadecyl), carbon number 1 Represents a cycloalkyl group of -20 (for example, cyclopentyl, cyclohexyl) or an allyl group, a substituent [for example, a halogen atom (for example, F, Cl, Br, I), a hydroxyl group, a cyano group, a nitro group, a carboxylic acid group, aryl group having 6 to 10 carbon atoms (e.g., phenyl, naphthyl), amino group having 0 to 20 carbon atoms _{(e.g., NH 2, NHCH 3, N} (C 2 H 5) 2, N (C 4 H 9) 2 N (C ₈ H ₁₇ ) ₂ , anilino, 4-methoxyanilino), an amide group having 1 to 20 carbon atoms (for example, acetylamino, hexanoylamino, benzoylamino, octadecanoyl) Amino), a carbamoyl group having 1 to 20 carbon atoms (for example, unsubstituted carbamoyl, methylcarbamoyl, ethylcarbamoyl, octylcarbamoyl, hexadecylcarbamoyl), an ester group having 2 to 20 carbon atoms (for example, methoxycarbonyl, ethoxycarbonyl, Phenoxycarbonyl, n-butoxycarbonyl, dodecyloxycarbonyl), alkoxy group having 1 to 20 carbon atoms or aryloxy group (methoxy, ethoxy, butoxy, isopropoxy, benzyloxy, phenoxy, octadecyloxy), sulfone having 1 to 20 carbon atoms Amido groups (for example, methanesulfonamide, ethanesulfonamide, butanesulfonamide, benzenesulfonamide, octanesulfonamide), sulfamoyl groups having 0 to 20 carbon atoms (for example, unsubstituted Famoyl, methylsulfamoyl, butylsulfamoyl, decylsulfamoyl) or a 5- or 6-membered heterocyclic ring (eg, pyridyl, pyrazolyl, morpholino, piperidino, pyrrolino, benzoxazolyl)) Good.

The aromatic group represented by R ^{1 to} R ¹¹ represents an aryl group having 6 to 10 carbon atoms (for example, phenyl or naphthyl), and is a substituent [for example, a substituent that the above-described aliphatic group may have. In addition to each group, it may have an alkyl group having 1 to 20 carbon atoms (for example, methyl, ethyl, butyl, t-butyl, octyl, etc.).

The heterocyclic group represented by R ^{1 to} R ¹¹ represents a 5- or 6-membered heterocyclic ring (for example, pyridine, piperidine, morpholine, pyrrolidine, pyrazole, pyrazolidine, pyrazoline, pyrazolone, benzoxazole) and a substituent (for example, the above-mentioned Each group mentioned as a substituent which the aromatic group may have.

Examples of the 5- or 6-membered ring formed by connecting R ⁹ and R ¹⁰ include a morpholine ring, a piperidine ring, and a pyrrolidine ring. The ring formed by connecting R ¹ and R ² or R ² and R ³ is preferably a 5- or 6-membered ring (for example, a benzene ring or a phthalimide ring).

Next, each group of general formula (II) is demonstrated. The aliphatic group represented by R ^{21 to} R ²⁴ has the same meaning as the aliphatic group represented by R ^{1 to} R ¹¹ in formula (I), and the aromatic group represented by R ^{21 to} R ²⁴ represents the formula (I It is synonymous with the aromatic group which R < ¹ > -R < ¹¹ > in I) represents.

These additives may be added at any time in the dope preparation step, but may be added to the final preparation step of the dope preparation step by adding a preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when a cellulose acylate film is a multilayer, the kind and addition amount of the additive of each layer may differ. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902, but these are conventionally known techniques. The glass transition point Tg measured by a dynamic viscoelasticity measuring device for cellulose acylate film (Vibron: DVA-225 (manufactured by IT Measurement Control Co., Ltd.)) is adjusted to 70 to 150 depending on the selection of the type and amount of these additives. More preferably, the glass transition point Tg is 80 to 135 ° C. That is, the cellulose acylate film according to the present invention has a glass transition point from the viewpoint of process suitability for polarizing plate processing and liquid crystal display device assembly. The point Tg is preferably within the above range.
Furthermore, regarding the additive, the Japan Institute of Invention and Innovation Technical Bulletin No. 2001-1745 (issued on March 15, 2001, Japan Institute of Invention) p. Those described in detail after 16 can be used as appropriate.

(Retardation expression agent)
In the present invention, it is preferable to use a retardation enhancer in order to greatly develop optical anisotropy and realize a preferable retardation value.
Examples of the retardation enhancer that can be used in the present invention include those composed of rod-shaped or discotic compounds.
As the rod-like or discotic compound, a compound having at least two aromatic rings can be used.
The addition amount of the retardation developer composed of the rod-like compound is preferably 0.1 to 30 parts by mass, and preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. Further preferred.
The disc-shaped retardation developing agent is preferably used in a range of 0.05 to 30 parts by mass, and in a range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. More preferably, it is used in the range of 0.2 to 15 parts by mass, and most preferably in the range of 0.5 to 10 parts by mass.
Since the discotic compound is superior to the rod-shaped compound in Rth retardation expression, it is preferably used when a particularly large Rth retardation is required.
Two or more retardation developing agents may be used in combination.
The retardation developer composed of a rod-like or discotic compound preferably has maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.

The discotic compound will be described. As the discotic compound, a compound having at least two aromatic rings can be used.
In the present specification, the “aromatic ring” includes an aromatic hetero ring in addition to an 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.
As the aromatic ring, benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring are preferable, In particular, a 1,3,5-triazine ring is preferably used. Specifically, for example, a compound disclosed in JP 2001-166144 A is preferably used as the discotic compound.

The number of aromatic rings contained in the discotic compound is preferably 2 to 20, more preferably 2 to 12, still more preferably 2 to 8, and most preferably 2 to 6. preferable.
The bond relationship between two aromatic rings can be classified into (a) a condensed ring, (b) a direct bond with a single bond, and (c) a bond through a linking group (for aromatic rings). , Spiro bonds cannot be formed). The connection relationship may be any of (a) to (c).

  Examples of the condensed ring (a condensed ring of two or more aromatic rings) include an indene ring, a naphthalene ring, an azulene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, an acenaphthylene ring, a biphenylene ring, a naphthacene ring, Pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indolizine ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring, purine ring, indazole ring, chromene ring, quinoline ring, isoquinoline Ring, quinolidine ring, quinazoline ring, cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, acridine ring, phenanthridine ring, xanthene ring, phenazine ring, phenothiazine ring, phenoxathiin ring, phenoxazine ring and thiant It includes emissions ring. Naphthalene ring, azulene ring, indole ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring and quinoline ring are preferred.

  The single bond (b) is preferably a bond between carbon atoms of two aromatic rings. Two aromatic rings may be bonded with two or more single bonds to form an aliphatic ring or a non-aromatic heterocyclic ring between the two aromatic rings.

The linking group in (c) is also preferably bonded to carbon atoms of two aromatic rings. The linking group is preferably an alkylene group, an alkenylene group, an alkynylene group, —CO—, —O—, —NH—, —S—, or a combination thereof. Examples of linking groups composed of combinations are shown below. In addition, the relationship between the left and right in the following examples of the linking group may be reversed.
c1: -CO-O-
c2: —CO—NH—
c3: -alkylene-O-
c4: —NH—CO—NH—
c5: —NH—CO—O—
c6: —O—CO—O—
c7: -O-alkylene-O-
c8: -CO-alkenylene-
c9: -CO-alkenylene-NH-
c10: -CO-alkenylene-O-
c11: -alkylene-CO-O-alkylene-O-CO-alkylene-
c12: -O-alkylene-CO-O-alkylene-O-CO-alkylene-O-
c13: -O-CO-alkylene-CO-O-
c14: -NH-CO-alkenylene-
c15: -O-CO-alkenylene-

The aromatic ring and the linking group may have a substituent.
Examples of substituents include halogen atoms (F, Cl, Br, I), hydroxyl groups, carboxyl groups, cyano groups, amino groups, nitro groups, sulfo groups, carbamoyl groups, sulfamoyl groups, ureido groups, alkyl groups, alkenyls. Group, alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, aliphatic sulfonamido group, aliphatic substituted amino group An aliphatic substituted carbamoyl group, an aliphatic substituted sulfamoyl group, an aliphatic substituted ureido group, and a non-aromatic heterocyclic group.

The alkyl group preferably has 1 to 8 carbon atoms. A chain alkyl group is preferable to a cyclic alkyl group, and a linear alkyl group is particularly preferable. The alkyl group may further have a substituent (eg, hydroxy group, carboxy group, alkoxy group, alkyl-substituted amino group). Examples of alkyl groups (including substituted alkyl groups) include methyl, ethyl, n-butyl, n-hexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl, and 2- A diethylaminoethyl group is included.
The alkenyl group preferably has 2 to 8 carbon atoms. A chain alkenyl group is preferable to a cyclic alkenyl group, and a linear alkenyl group is particularly preferable. The alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, an allyl group, and a 1-hexenyl group.
The alkynyl group preferably has 2 to 8 carbon atoms. A chain alkynyl group is preferable to a cyclic alkynyl group, and a linear alkynyl group is particularly preferable. The alkynyl group may further have a substituent. Examples of the alkynyl group include ethynyl group, 1-butynyl group and 1-hexynyl group.

The aliphatic acyl group preferably has 1 to 10 carbon atoms. Examples of the aliphatic acyl group include an acetyl group, a propanoyl group, and a butanoyl group.
The aliphatic acyloxy group preferably has 1 to 10 carbon atoms. Examples of the aliphatic acyloxy group include an acetoxy group.
The number of carbon atoms of the alkoxy group is preferably 1 to 8. The alkoxy group may further have a substituent (eg, alkoxy group). Examples of the alkoxy group (including a substituted alkoxy group) include a methoxy group, an ethoxy group, a butoxy group, and a methoxyethoxy group.
The alkoxycarbonyl group preferably has 2 to 10 carbon atoms. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.
The number of carbon atoms of the alkoxycarbonylamino group is preferably 2 to 10. Examples of the alkoxycarbonylamino group include a methoxycarbonylamino group and an ethoxycarbonylamino group.

The alkylthio group preferably has 1 to 12 carbon atoms. Examples of the alkylthio group include a methylthio group, an ethylthio group, and an octylthio group.
The alkylsulfonyl group preferably has 1 to 8 carbon atoms. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.
The aliphatic amide group preferably has 1 to 10 carbon atoms. Examples of the aliphatic amide group include an acetamide group.
The aliphatic sulfonamide group preferably has 1 to 8 carbon atoms. Examples of the aliphatic sulfonamido group include a methanesulfonamido group, a butanesulfonamido group, and an n-octanesulfonamido group.
The number of carbon atoms of the aliphatic substituted amino group is preferably 1 to 10. Examples of the aliphatic substituted amino group include a dimethylamino group, a diethylamino group, and a 2-carboxyethylamino group.
The aliphatic substituted carbamoyl group preferably has 2 to 10 carbon atoms. Examples of the aliphatic substituted carbamoyl group include a methylcarbamoyl group and a diethylcarbamoyl group.
The aliphatic substituted sulfamoyl group preferably has 1 to 8 carbon atoms. Examples of the aliphatic substituted sulfamoyl group include a methylsulfamoyl group and a diethylsulfamoyl group.
The number of carbon atoms in the aliphatic substituted ureido group is preferably 2 to 10. Examples of the aliphatic substituted ureido group include a methylureido group.
Examples of the non-aromatic heterocyclic group include a piperidino group and a morpholino group.
The molecular weight of the retardation developer composed of a discotic compound is preferably 300 to 800.

  In the present invention, in addition to the aforementioned discotic compound, a rod-shaped compound having a linear molecular structure can also be preferably used. The linear molecular structure means that the molecular structure of the rod-like compound is linear in the most thermodynamically stable structure. The most thermodynamically stable structure can be obtained by crystal structure analysis or molecular orbital calculation. For example, molecular orbital calculation can be performed using molecular orbital calculation software (eg, WinMOPAC2000, manufactured by Fujitsu Limited) to obtain a molecular structure that minimizes the heat of formation of a compound. The molecular structure being linear means that in the thermodynamically most stable structure obtained by calculation as described above, the angle of the main chain constituting the molecular structure is 140 degrees or more.

As the rod-shaped compound, those having at least two aromatic rings are preferable, and as the rod-shaped compound having at least two aromatic rings, a compound represented by the following general formula (1) is preferable.

Formula (1): Ar ¹ -L ¹ -Ar ²

In the general formula (1), Ar ¹ and Ar ² are each independently an aromatic group.
In the present specification, the aromatic group includes an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.
An aryl group and a substituted aryl group are more preferable than an aromatic heterocyclic group and a substituted aromatic heterocyclic group. The heterocycle of the aromatic heterocyclic group is generally unsaturated. 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 a hetero atom, a nitrogen atom, an oxygen atom or a sulfur atom is preferable, and a nitrogen atom or a sulfur atom is more preferable.
As the aromatic ring of the aromatic group, a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring and a pyrazine ring are preferable, and a benzene ring is particularly preferable. .

  Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br, I), a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkylamino group (eg, methyl). Amino group, ethylamino group, butylamino group, dimethylamino group), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (eg, N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N-dimethylcarbamoyl group) ), Sulfamoyl group, alkylsulfamoyl group (eg, N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group), ureido group, alkylureido group (eg, N -Methylureido group, N, N-dimethylureido group, N, N, N'-trimethylureido group), alkyl group (eg, Methyl, ethyl, propyl, butyl, pentyl, heptyl, octyl, isopropyl, s-butyl, t-amyl, cyclohexyl, cyclopentyl), alkenyl (eg, vinyl, allyl) Group, hexenyl group), alkynyl group (eg, ethynyl group, butynyl group), acyl group (eg, formyl group, acetyl group, butyryl group, hexanoyl group, lauryl group), acyloxy group (eg, acetoxy group, butyryloxy group, Hexanoyloxy group, lauryloxy group), alkoxy group (eg, methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, heptyloxy group, octyloxy group), aryloxy group (eg, phenoxy group), Alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, Ropoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, heptyloxycarbonyl group), aryloxycarbonyl group (eg, phenoxycarbonyl group), alkoxycarbonylamino group (eg, butoxycarbonylamino group, hexyloxycarbonylamino group) , Alkylthio groups (eg, methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group, octylthio group), arylthio groups (eg, phenylthio group), alkylsulfonyl groups (eg, methylsulfonyl group, ethylsulfonyl group) , Propylsulfonyl group, butylsulfonyl group, pentylsulfonyl group, heptylsulfonyl group, octylsulfonyl group), amide group (eg, acetamido group, butyramide group, hexylamide group, Uriruamido group) and a non-aromatic Hajime Tamaki (e.g., morpholyl groups include pyrazinyl group).

Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom, a cyano group, a carboxyl group, a hydroxyl group, an amino group, an alkyl-substituted amino group, an acyl group, an acyloxy group, an amide group, an alkoxycarbonyl group, Alkoxy groups, alkylthio groups and alkyl groups are preferred.
The alkyl part and the alkyl group of the alkylamino group, alkoxycarbonyl group, alkoxy group and alkylthio group may further have a substituent. Examples of alkyl moieties and substituents of alkyl groups include halogen atom, hydroxyl, carboxyl, cyano, amino, alkylamino group, nitro, sulfo, carbamoyl, alkylcarbamoyl group, sulfamoyl, alkylsulfamoyl group, ureido, alkylureido Group, alkenyl group, alkynyl group, acyl group, acyloxy group, acylamino group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, alkoxycarbonylamino group, alkylthio group, arylthio group, alkylsulfonyl group, amide group And non-aromatic heterocyclic groups. As the substituent for the alkyl moiety and the alkyl group, a halogen atom, hydroxyl, amino, alkylamino group, acyl group, acyloxy group, acylamino group, alkoxycarbonyl group and alkoxy group are preferable.

In the general formula (1), L ¹ is a divalent linking group selected from an alkylene group, an alkenylene group, an alkynylene group, —O—, —CO— and a combination thereof.
The alkylene group may have a cyclic structure. As the cyclic alkylene group, cyclohexylene is preferable, and 1,4-cyclohexylene is particularly preferable. As the chain alkylene group, a linear alkylene group is more preferable than a branched alkylene group.
The alkylene group preferably has 1 to 20 carbon atoms, more preferably 1 to 15, more preferably 1 to 10, still more preferably 1 to 8, and most preferably 1 to 6 carbon atoms. It is.

The alkenylene group and alkynylene group preferably have a chain structure rather than a cyclic structure, and more preferably have a linear structure rather than a branched chain structure.
The number of carbon atoms of the alkenylene group and the alkynylene group is preferably 2 to 10, more preferably 2 to 8, further preferably 2 to 6, further preferably 2 to 4, and most preferably 2. (Vinylene or ethynylene).
The arylene group preferably has 6 to 20 carbon atoms, more preferably 6 to 16, and still more preferably 6 to 12.

In the molecular structure of the general formula (1), the angle formed by Ar ¹ and Ar ² across L ¹ is preferably 140 degrees or more.
The rod-like compound can be synthesized by a method described in the literature. As literature, Mol. Cryst. Liq. Cryst. 53, 229 (1979), 89, 93 (1982), 145, 111 (1987), 170, 43 (1989), J. Am. Am. Chem. Soc. 113, 1349 (1991), 118, 5346 (1996), 92, 1582 (1970); Org. Chem. 40, 420 pages (1975), Tetrahedron, 48, No. 16, page 3437 (1992).
Further, it is more preferable to use a rod-like compound represented by the general formula (I). The compound represented by general formula (I) is demonstrated below.

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, and R ¹ , R ² , R ³ At least one .R ⁸ which represents an electron-donating group is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, aryl having 6 to 12 carbon atoms of R ⁴ and R ⁵ A group, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.

In general formula (I), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent, and the substituent will be described later. The substituent T can be applied.
At least one of R ¹ , R ² , R ³ , R ⁴ and R ⁵ represents an electron donating group. Preferably, one of R ¹ , R ³ or R ⁵ is an electron donating group, and R ³ is more preferably an electron donating group.
An electron donating group is one having a Hammett σp value of 0 or less. Rev. , 91, 165 (1991), and those having Hammet's σp value of 0 or less are preferably applicable, and those having −0.85 to 0 are more preferably used. Examples thereof include an alkyl group, an alkoxy group, an amino group, and a hydroxyl group.
The electron donating group is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably carbon). 1 to 4).

R ¹ is preferably a hydrogen atom or an electron donating group, more preferably an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably an alkyl group having 1 to 4 carbon atoms or a carbon number 1 to 12 Particularly preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Most preferred is a methoxy group.

R ² is preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom or an alkyl group (preferably a carbon number). 1 to 4, more preferably a methyl group), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to carbon atoms). 4). Particularly preferred are a hydrogen atom, a methyl group and a methoxy group.

R ³ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, still more preferably an alkyl group or an alkoxy group, particularly preferably. An alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Most preferred are n-propoxy group, ethoxy group and methoxy group.

R ⁴ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , An alkoxy group having 1 to 12 carbon atoms (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms), particularly preferably. Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and most preferably a hydrogen atom, a methyl group, or a methoxy group.

R ⁵ is preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom or an alkyl group (preferably a carbon number). 1 to 4 is more preferably a methyl group), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). It is. Particularly preferred are a hydrogen atom, a methyl group and a methoxy group.

R ⁶ , R ⁷ , R ⁹ and R ¹⁰ are preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a halogen atom, more preferably a hydrogen atom or a halogen atom. More preferably a hydrogen atom.

R ⁸ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy having 6 to 12 carbon atoms. Group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom, which may have a substituent if possible. The group T can be applied.
R ⁸ is preferably an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryloxy group having 2 to 12 carbon atoms. And more preferably an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms, still more preferably an alkoxy group having 1 to 12 carbon atoms (preferably Is preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and particularly preferably a methoxy group, an ethoxy group, n-propoxy group, iso-propoxy group and n-butoxy group.

Of the general formula (I), the following general formula (IA) is more preferable.
General formula (IA)

(Wherein R ¹¹ represents an alkyl group. R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent. R ⁸ Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, Represents an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.)
In the general formula (IA), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are respectively synonymous with those in the general formula (I), and The preferable range is also the same.

In General Formula (IA), R ¹¹ represents an alkyl group having 1 to 12 carbon atoms, and the alkyl group represented by R ¹¹ may be linear or branched, and further has a substituent. However, preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms, and particularly preferably an alkyl group having 1 to 4 carbon atoms (for example, , Methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group and the like.

Of the general formula (I), the following general formula (IB) is more preferable.
General formula (IB)

(Wherein R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom or a substituent. R ¹¹ is an alkyl having 1 to 12 carbon atoms. X represents an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms. A group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.)

In the general formula (IB), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ , and R ¹⁰ have the same meanings as those in the general formula (I), and preferred ranges are also included. It is the same.
In general formula (IB), R < ¹¹ > is synonymous with those in general formula (IA), and the preferred range is also the same.

In general formula (IB), X is an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or 6 carbon atoms. Represents an aryloxy group having 12 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom.
When all of R ¹ , R ² , R ⁴ and R ⁵ are hydrogen atoms, X is preferably an alkyl group, alkynyl group, aryl group, alkoxy group or aryloxy group, more preferably an aryl group, alkoxy group Group, aryloxy group, more preferably alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms). And particularly preferably a methoxy group, a methoxy group, an n-propoxy group, an iso-propoxy group or an n-butoxy group.

When at least one of R ¹ , R ² , R ⁴ and R ⁵ is a substituent, X is preferably an alkynyl group, an aryl group, an alkoxycarbonyl group or a cyano group, more preferably an aryl group (preferably Is a cyano group or an alkoxycarbonyl group (preferably a carbon number of 2 to 12), more preferably an aryl group (preferably an aryl group of 6 to 12 carbon atoms, more preferably a phenyl group). , P-cyanophenyl group and p-methoxyphenyl group), an alkoxycarbonyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, still more preferably 2 to 4 carbon atoms, and particularly preferably methoxycarbonyl group). , Ethoxycarbonyl, n-propoxycarbonyl), cyano group, particularly preferably phenyl group, methoxy group. Group, an ethoxycarbonyl group, n- propoxycarbonyl group, a cyano group.

Of the general formula (I), the following general formula (IC) is more preferable.
General formula (IC)

In the formula, R ¹ , R ² , R ⁴ , R ⁵ , R ¹¹ and X have the same meanings as those in formula (IB), and preferred ranges are also the same.

Among the compounds represented by the general formula (I), a compound represented by the following general formula (ID) is more preferable.
Formula (ID)

(Wherein R ² , R ⁴ and R ⁵ have the same meanings as those in formula (IC), and preferred ranges are also the same. R ²¹ and R ²² each independently has 1 to 4 carbon atoms. X ¹ is an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, or a cyano group.

R ²¹ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably an ethyl group or a methyl group.
R ²² represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

X ¹ is an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, or a cyano group, preferably an aryl group having 6 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a cyano group. More preferably a phenyl group, a p-cyanophenyl group, a p-methoxyphenyl group, a methoxycarbonyl, an ethoxycarbonyl, an n-propoxycarbonyl, a cyano group, and still more preferably a phenyl group, a methoxycarbonyl group, an ethoxycarbonyl group, n-propoxycarbonyl group and cyano group.

Of the general formula (I), the following general formula (IE) is most preferable.
Formula (IE)

(In the formula, R ² , R ⁴ and R ⁵ have the same meanings as those in formula (ID) and preferred ranges are the same, but one of them is a group represented by —OR ¹³ ( R ¹³ is an alkyl group having 1 to 4 carbon atoms.) R ²¹ , R ²² and X ¹ have the same meanings as those in formula (ID), and preferred ranges are also the same.)

In the general formula (IE), R ² , R ⁴ and R ⁵ have the same meanings as those in the general formula (ID), and preferred ranges are also the same, but any one of them is represented by —OR ^13. (R ¹³ is an alkyl group having 1 to 4 carbon atoms), preferably R ⁴ and R ⁵ are groups represented by —OR ¹³ , more preferably R ⁴ is —OR ^13. It is group represented by these.
R ¹³ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

The aforementioned substituent T will be described below.
Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, for example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6-30 carbon atoms) More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.), an alkoxy group (preferably having a carbon number) 1 to 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably 6 to 20 carbon atoms, more Preferably it has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy and the like. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, and pivaloyl). An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group ( Preferably it has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, and examples thereof include phenyloxycarbonyl, etc.), an acyloxy group (preferably 2 to 20 carbon atoms, More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms. Nzoyloxy and the like. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino), aryloxycarbonylamino group (preferably having carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, and sulfonylamino groups (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. And sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl and methylsulfamoyl). , Dimethylsulfamoyl, phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl). , Methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, Ethylthio etc.), arylthio group (preferably Has 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably Has 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). For example, ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms) More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, diethyl phosphoric acid amide, phenylphosphoric acid amide etc. are mentioned. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl , Morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms). For example, trimethylsilyl, triphenylsilyl, etc.) . These substituents may be further substituted.

  Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  Hereinafter, the compound represented by formula (I) will be described in detail with specific examples, but the present invention is not limited to the following specific examples.

The compound represented by the general formula (I) of the present invention can be synthesized by a general ester reaction of a substituted benzoic acid and a phenol derivative, and any reaction may be used as long as it is an ester bond forming reaction. Examples thereof include a method of converting a substituted benzoic acid to an acid halide and then condensing with phenol, a method of dehydrating the substituted benzoic acid and a phenol derivative using a condensing agent or a catalyst, and the like.
In view of the production process and the like, a method in which the substituted benzoic acid is functionally converted to an acid halide and then condensed with phenol is preferable.

  Reaction solvents include hydrocarbon solvents (preferably toluene and xylene), ether solvents (preferably dimethyl ether, tetrahydrofuran, dioxane, etc.), ketone solvents, ester solvents, acetonitrile, dimethylformamide, dimethyl Acetamide or the like can be used. These solvents may be used alone or in admixture of several kinds, and preferred reaction solvents are toluene, acetonitrile, dimethylformamide and dimethylacetamide.

The reaction temperature is preferably 0 to 150 ° C, more preferably 0 to 100 ° C, still more preferably 0 to 90 ° C, and particularly preferably 20 ° C to 90 ° C.
In this reaction, it is preferable not to use a base. When a base is used, either an organic base or an inorganic base may be used, preferably an organic base such as pyridine, tertiary alkylamine (preferably triethylamine, ethyldiisopropyl). Pyramine and the like).

  Two or more rod-shaped compounds whose maximum absorption wavelength (λmax) is shorter than 250 nm in the ultraviolet absorption spectrum of the solution may be used in combination.

[Matting agent fine particles]
It is preferable to add fine particles as a matting agent to the cellulose acylate film according to the present invention. The fine particles used in the present invention 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, silica Mention may be made of magnesium and calcium phosphates. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more. Those having an average primary particle size as small as 5 to 16 nm are more preferred because they can reduce the haze of the film. The apparent specific gravity is preferably 90 to 200 g / liter or more, and more preferably 100 to 200 g / liter or more. A larger apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are improved.
The amount of silicon dioxide fine particles used is preferably 0.01 to 0.3 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate.

These fine particles usually form secondary particles having an average particle diameter of 0.1 to 3.0 μm, and these fine particles are present as aggregates of primary particles in the film, and 0.1 to 0.1 μm on the film surface. An unevenness of 3.0 μm is formed. The secondary average particle size is preferably from 0.2 μm to 1.5 μm, more preferably from 0.4 μm to 1.2 μm, and most preferably from 0.6 μm to 1.1 μm. When it is larger than 1.5 μm, the haze becomes strong, and when it is smaller than 0.2 μm, the effect of preventing stain is reduced.
The primary and secondary particle diameters are determined by observing the particles in the film with a scanning electron microscope and using the diameter of a circle circumscribing the particles as the particle diameter. Also, 200 particles are observed at different locations, and the average value is taken as the average particle diameter.

  As fine particles of silicon dioxide, for example, commercially available products such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.) can be used. 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.

  Among these, Aerosil 200V and Aerosil R972V are fine particles of silicon dioxide having a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more, and the coefficient of friction is maintained while keeping the turbidity of the optical film low. It is particularly preferable because it has a great effect of reducing the effect.

In order to obtain a cellulose acylate film having particles having a small secondary average particle size in the present invention, several methods are conceivable when preparing a fine particle dispersion. For example, a method of preparing a fine particle dispersion in which a solvent and fine particles are mixed with stirring in advance, adding this fine particle dispersion to a small amount of cellulose acylate solution separately prepared, stirring and dissolving, and further mixing with the main cellulose acylate dope solution There is. This method is a preferable preparation method in that the dispersibility of the silicon dioxide fine particles is good and the silicon dioxide fine particles are more difficult to reaggregate. In addition, after adding a small amount of cellulose ester to the solvent and dissolving with stirring, add the fine particles to this and disperse with a disperser to make this fine particle additive solution, and mix this fine particle additive solution with the dope solution using an inline mixer There is also a way to do it. The present invention is not limited to these methods, but the concentration of silicon dioxide when the silicon dioxide fine particles are mixed and dispersed with a solvent or the like is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and 15 to 20%. Mass% is most preferred. A higher dispersion concentration is preferable because the liquid turbidity with respect to the added amount is lowered, and haze and aggregates are improved. The addition amount of the matting agent in the final cellulose acylate dope solution is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.3 g, and 0.08 to 0.16 g per 1 m ^2. Most preferred.

  The solvent used is preferably lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. Although it does not specifically limit as solvents other than a lower alcohol, It is preferable to use the solvent used at the time of film forming of a cellulose ester.

Next, the organic solvent in which the cellulose acylate according to the present invention is dissolved will be described.
In the present invention, any of a chlorinated solvent containing a chlorinated organic solvent as a main solvent and a non-chlorinated solvent not containing a chlorinated organic solvent can be used as the organic solvent.
(Chlorine solvent)
In preparing the cellulose acylate solution according to the present invention, a chlorinated organic solvent is preferably used as the main solvent. In the present invention, the type of the chlorinated organic solvent is not particularly limited as long as the object can be achieved within a range where the cellulose acylate can be dissolved, cast and formed. These chlorinated organic solvents are preferably dichloromethane and chloroform. Particularly preferred is dichloromethane. In addition, there is no particular problem in mixing an organic solvent other than the chlorinated organic solvent. In that case, it is necessary to use at least 50% by mass of dichloromethane in the total amount of the organic solvent. Other organic solvents used in combination with the chlorinated organic solvent in the present invention will be described below. That is, as another preferable organic solvent, a solvent selected from esters, ketones, ethers, alcohols, hydrocarbons and the like having 3 to 12 carbon atoms is preferable. Esters, ketones, ethers and alcohols may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO— and —COO—) can also be used as a solvent. For example, other functional groups such as alcoholic hydroxyl groups can be used. You may have group simultaneously. In the case of a solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

The alcohol used in combination with the chlorinated organic solvent may be linear, branched or cyclic, and among them, saturated aliphatic hydrocarbon is preferable. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Furthermore, the hydrocarbon may be linear, branched or cyclic. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene.
Examples of combinations of chlorinated organic solvents and other organic solvents include the following compositions, but are not limited thereto.

Dichloromethane / methanol / ethanol / butanol (80/10/5/5, parts by mass),
Dichloromethane / acetone / methanol / propanol (80/10/5/5, parts by mass),
Dichloromethane / methanol / butanol / cyclohexane (80/10/5/5, parts by mass),
Dichloromethane / methyl ethyl ketone / methanol / butanol (80/10/5/5, parts by mass),
・ Dichloromethane / acetone / methyl ethyl ketone / ethanol / isopropanol (75/8/5/5/7, parts by mass)
・ Dichloromethane / cyclopentanone / methanol / isopropanol (80/7/5/8, part by mass)
Dichloromethane / methyl acetate / butanol (80/10/10, parts by mass),
Dichloromethane / cyclohexanone / methanol / hexane (70/20/5/5, parts by mass)
Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),
Dichloromethane / 1, 3 dioxolane / methanol / ethanol (70/20/5/5, parts by mass),
Dichloromethane / dioxane / acetone / methanol / ethanol (60/20/10/5/5, parts by mass),
Dichloromethane / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5, parts by mass)
Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (70/10/10/5/5, parts by mass),
Dichloromethane / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass),
Dichloromethane / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass),
Dichloromethane / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass),
And so on.

(Non-chlorine solvent)
Next, a non-chlorine organic solvent that is preferably used in preparing a cellulose acylate solution according to the present invention will be described. In the present invention, the non-chlorine organic solvent is not particularly limited as long as the object can be achieved as long as the cellulose acylate can be dissolved and cast and formed into a film. The non-chlorine organic solvent used in the present invention is preferably a solvent selected from esters, ketones and ethers having 3 to 12 carbon atoms. Esters, ketones and ethers may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO—, and —COO—) can also be used as a main solvent, such as an alcoholic hydroxyl group. It may have a functional group of In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  The non-chlorine organic solvent used in the above cellulose acylate is selected from the various viewpoints described above, and is preferably as follows. That is, the non-chlorine solvent is preferably a mixed solvent containing the non-chlorine organic solvent as a main solvent, and is a mixed solvent of three or more different solvents, wherein the first solvent is methyl acetate, ethyl acetate, At least one selected from methyl formate, ethyl formate, acetone, dioxolane, and dioxane, or a mixture thereof; the second solvent is selected from ketones having 4 to 7 carbon atoms or acetoacetate; The solvent is a mixed solvent selected from alcohols or hydrocarbons having 1 to 10 carbon atoms, more preferably alcohols having 1 to 8 carbon atoms. Note that when the first solvent is a mixed liquid of two or more kinds of solvents, the second solvent may be omitted. The first solvent is more preferably methyl acetate, acetone, methyl formate, ethyl formate, or a mixture thereof, and the second solvent is preferably methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl acetyl acetate, or a mixed solvent thereof. It may be.

  The alcohol as the third solvent may be linear, branched or cyclic, and is preferably a saturated aliphatic hydrocarbon. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Furthermore, the hydrocarbon may be linear, branched or cyclic. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene. These alcohols and hydrocarbons as the third solvent may be used alone or in combination of two or more, and are not particularly limited. As the third solvent, preferred specific compounds include alcohol, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and cyclohexanol, cyclohexane, hexane, Are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol.

  The mixing ratio of the above three types of mixed solvents is 20 to 95% by mass for the first solvent, 2 to 60% by mass for the second solvent, and 2 to 30% by mass for the third solvent in the total amount of the mixed solvent. The first solvent is preferably 30 to 90% by mass, the second solvent is 3 to 50% by mass, and the third alcohol is preferably 3 to 25% by mass. . In particular, it is preferable that the first solvent is 30 to 90% by mass, the second solvent is 3 to 30% by mass, and the third solvent is alcohol and 3 to 15% by mass. The non-chlorine-based organic solvent used in the present invention described above is more specifically described in JIII Journal of Technical Disclosure No. 2001-1745 (issued March 15, 2001, Invention Association) p. 12-16. Preferred combinations of non-chlorine organic solvents of the present invention can include the following, but are not limited thereto.

-Methyl acetate / acetone / methanol / ethanol / butanol (75/10/5/5/5, parts by mass),
-Methyl acetate / acetone / methanol / ethanol / propanol (75/10/5/5/5, parts by mass),
Methyl acetate / acetone / methanol / butanol / cyclohexane (75/10/5/5/5, parts by mass),
・ Methyl acetate / acetone / ethanol / butanol (81/8/7/4, parts by mass)
・ Methyl acetate / acetone / ethanol / butanol (82/10/4/4, parts by mass)
・ Methyl acetate / acetone / ethanol / butanol (80/10/4/6, part by mass)
Methyl acetate / methyl ethyl ketone / methanol / butanol (80/10/5/5, parts by mass),
-Methyl acetate / acetone / methyl ethyl ketone / ethanol / isopropanol (75/8/5/5/7, parts by mass)
Methyl acetate / cyclopentanone / methanol / isopropanol (80/7/5/8, parts by mass),
Methyl acetate / acetone / butanol (85/10/5, parts by mass),
Methyl acetate / cyclopentanone / acetone / methanol / butanol (60/15/14/5/6, parts by mass),
-Methyl acetate / cyclohexanone / methanol / hexane (70/20/5/5, parts by mass)
Methyl acetate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),
Methyl acetate / 1,3-dioxolane / methanol / ethanol (70/20/5/5, parts by mass),
Methyl acetate / dioxane / acetone / methanol / ethanol (60/20/10/5/5, parts by mass),
Methyl acetate / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5, parts by mass),

Methyl formate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5, parts by mass),
-Methyl formate / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5, parts by mass)
Acetone / methyl acetoacetate / methanol / ethanol (65/20/10/5, parts by mass)
Acetone / cyclopentanone / ethanol / butanol (65/20/10/5, parts by mass)
Acetone / 1,3-dioxolane / ethanol / butanol (65/20/10/5, parts by mass)
1,3-dioxolane / cyclohexanone / methyl ethyl ketone / methanol / butanol (55/20/10/5/5/5, parts by mass)
Etc.
Further, a cellulose acylate solution prepared by the following method can also be used.
A method of preparing a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (81/8/7/4, parts by mass), adding 2 parts by weight of butanol after filtration and concentration, and methyl acetate / acetone / ethanol / Butanol (84/10/4/2, parts by mass) A method for adding a cellulose acylate solution after filtration and concentration, and adding 4 parts by mass of butanol after addition. Methyl acetate / acetone / ethanol (84/10/6, In addition to the above non-chlorine organic solvent of the present invention, dichloromethane is added to the dope used in the present invention. You may make it contain 10 mass% or less of the total amount of organic solvents.

(Characteristics of cellulose acylate solution)
The cellulose acylate solution is preferably a solution obtained by dissolving cellulose acylate in the organic solvent at a concentration of 10 to 30% by mass from the viewpoint of film forming casting suitability, and more preferably 13 to 27% by mass. It is particularly preferably 15 to 25% by mass. The method for carrying out the cellulose acylate at these concentrations may be carried out so as to obtain a predetermined concentration at the stage of dissolution, or it is prepared as a low-concentration solution (for example, 9 to 14% by mass) and then concentrated as described later You may adjust to a predetermined high concentration solution by a process. Furthermore, after making a cellulose acylate solution with a high concentration in advance, various additives may be added to obtain a predetermined cellulose acylate solution with a low concentration, and any method makes the cellulose acylate solution concentration of the present invention. If implemented, there is no particular problem.

Next, in the present invention, it is stripped that the aggregate molecular weight of cellulose acylate in a diluted solution in which the cellulose acylate solution is 0.1 to 5% by mass with an organic solvent having the same composition is 150,000 to 15 million. It is preferable in terms of improving the properties. More preferably, the associated molecular weight is 180,000 to 9 million. This associated molecular weight can be determined by a static light scattering method. In that case, it is preferable to dissolve so that the inertial square radius required at the same time is 10 to 200 nm. A more preferable inertial square radius is 20 to 200 nm. Furthermore, it is preferable to dissolve so that the second virial coefficient is −2 × 10 ⁻⁴ to + 4 × 10 ^−4, and more preferably, the second virial coefficient is −2 × 10 ⁻⁴ to + 2 × 10 ^−4. It is.

Here, the definition of the association molecular weight, the inertial square radius, and the second virial coefficient in the present invention will be described. These are measured using the static light scattering method according to the following method. Although the measurement is performed in a dilute region for the convenience of the apparatus, these measured values reflect the behavior of the dope in the high concentration region of the present invention.
First, cellulose acylate is dissolved in a solvent used for the dope to prepare 0.1 mass%, 0.2 mass%, 0.3 mass%, and 0.4 mass% solutions. In order to prevent moisture absorption, the cellulose acylate is dried at 120 ° C. for 2 hours and is measured at 25 ° C. and 10% RH. The dissolution method is carried out according to the method employed at the time of dope dissolution (room temperature dissolution method, cooling dissolution method, high temperature dissolution method). Subsequently, these solutions and the solvent are filtered through a 0.2 μm Teflon filter. Then, the static light scattering of the filtered solution is measured at an interval of 10 ° from 30 ° to 140 ° at 25 ° C. using a light scattering measuring device (DLS-700 manufactured by Otsuka Electronics Co., Ltd.). The obtained data is analyzed by the BERRY plot method. In addition, the refractive index required for this analysis uses the value of the solvent calculated | required with the Abbe refractive system, and the refractive index concentration gradient (dn / dc) uses the differential refractometer (Otsuka Electronics Co., Ltd. DRM-1021). Measure using the solvent and solution used for light scattering measurement.

(Dope preparation)
Next, preparation of a cellulose acylate solution (dope) will be described. The method for dissolving cellulose acylate is not particularly limited, and may be room temperature, and further, a cooling dissolution method or a high temperature dissolution method, and further a combination thereof. With respect to these, for example, JP-A-5-163301, JP-A-61-106628, JP-A-58-127737, JP-A-9-95544, JP-A-10-95854, JP-A-10-45950, JP 2000-53784, JP 11-322946, JP 11-322947, JP 2-276830, JP 2000-273239, JP 11-71463, JP 04-259511, Special JP 2000-273184, JP-A-11-323017, JP-A-11-302388, etc. describe methods for preparing cellulose acylate solutions. The above-described method for dissolving cellulose acylate in an organic solvent is applicable to the present invention as long as it is within the scope of the present invention. For details of these, particularly for non-chlorine-based solvent systems, the Japan Society for Invention and Innovation Publication No. 2001-1745 (issued March 15, 2001, Japan Society for Invention) p. It is carried out in the manner described in detail in 22-25. Further, the cellulose acylate dope solution according to the present invention is usually subjected to solution concentration and filtration. Similarly, the Japan Society for Invention and Innovation Technical Report No. 2001-1745 (issued March 15, 2001, Invention Association) p. 25 in detail. In addition, when it melt | dissolves at high temperature, it is the case where it is more than the boiling point of the organic solvent to be used, and in that case, it uses in a pressurized state.

It is preferable that the cellulose acylate solution has a viscosity and a dynamic storage elastic modulus within the ranges described below because it is easy to cast. 1 mL of the sample solution is measured with a rheometer (CLS 500) using Steel Cone (both manufactured by TA Instruments) having a diameter of 4 cm / 2 °. Measurement conditions were measured by varying the range from 40 ° C. to −10 ° C. at 2 ° C./min using Oscillation Step / Temperature Ramp, and static non-Newtonian viscosity n ^* (Pa · s) at 40 ° C. and storage at −5 ° C. The elastic modulus G ′ (Pa) is obtained. The sample solution is preliminarily kept at the measurement start temperature until the liquid temperature becomes constant, and then the measurement is started. In the present invention, the viscosity at 40 ° C. is 1 to 400 Pa · s, the dynamic storage elastic modulus at 15 ° C. is preferably 500 Pa or more, and more preferably the viscosity at 40 ° C. is 10 to 200 Pa · s. Thus, the dynamic storage elastic modulus at 15 ° C. is 1,000 to 1,000,000. Furthermore, it is preferable that the dynamic storage elastic modulus at low temperature is larger. For example, when the casting support is −5 ° C., the dynamic storage elastic modulus is preferably 10,000 to 1,000,000 Pa at −5 ° C. When the body is at −50 ° C., the dynamic storage elastic modulus at −50 ° C. is preferably 10,000 to 5 million Pa.

  In the present invention, since the above-mentioned specific cellulose acylate is used, it is characterized in that a high concentration dope is obtained, and a cellulose acylate having a high concentration and excellent stability without relying on a means of concentration. A solution is obtained. Furthermore, in order to make it easy to melt | dissolve, after making it melt | dissolve at a low density | concentration, you may concentrate using a concentration means. The concentration method is not particularly limited. For example, the low-concentration solution is guided between the cylindrical body and the rotation trajectory of the outer periphery of the rotating blade rotating in the circumferential direction, and the temperature between the solution and the solution. A method of obtaining a high-concentration solution while evaporating the solvent by giving a difference (for example, JP-A-4-259511), a heated low-concentration solution is blown into the container from the nozzle, and the solution is applied from the nozzle to the inner wall of the container In which the solvent is flash evaporated and the solvent vapor is withdrawn from the container and the concentrated solution is withdrawn from the bottom of the container (eg, US Pat. No. 2,541,012, US Pat. No. 2,858,229, US Pat. No. 4,414,341, US Pat. No. 4,504,355, etc.).

  Prior to casting, it is preferable to filter off foreign matters such as undissolved matter, dust, and impurities using a suitable filter medium such as a wire mesh or flannel. For the filtration of the cellulose acylate solution, it is preferable to use a filter having an absolute filtration accuracy of 0.1 to 100 μm, and it is more preferable to use a filter having an absolute filtration accuracy of 0.5 to 25 μm. The thickness of the filter is preferably 0.1 to 10 mm, and more preferably 0.2 to 2 mm. In that case, the filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, further 1.0 MPa or less, and particularly preferably 0.2 MPa or less. As the filter medium, conventionally known materials such as glass fibers, cellulose fibers, filter paper, fluororesins such as tetrafluoroethylene resin can be preferably used, and ceramics, metals and the like are particularly preferably used. The viscosity of the cellulose acylate solution immediately before film formation may be in a range that can be cast during film formation, and is usually prepared in a range of 10 Pa · s to 2000 Pa · s, preferably 30 Pa · s to 1000 Pa. · S is more preferable, and 40 Pa · s to 500 Pa · s is more preferable. The temperature at this time is not particularly limited as long as it is a temperature at the time of casting, but is preferably −5 to + 70 ° C., more preferably −5 to + 55 ° C.

(Film formation)
The cellulose acylate film according to the present invention can be obtained by forming a film using the cellulose acylate solution. As the film forming method and equipment, a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose triacetate film are used. The dope (cellulose acylate solution) prepared from the dissolving machine (kettle) is temporarily stored in a storage kettle, and the foam contained in the dope is defoamed for final preparation. The dope is sent from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the number of rotations. The dry-dried dope film (also referred to as web) is peeled off from the metal support at a peeling point that is uniformly cast on the metal support and substantially rounds the metal support. Both ends of the obtained web are sandwiched between clips, transported by a tenter while keeping the width, dried, then transported by a roll group of a drying device, dried, and wound up to a predetermined length by a winder. The combination of the tenter and the roll group dryer varies depending on the purpose. In the solution casting film forming method used for the functional protective film for electronic displays, in addition to the solution casting film forming apparatus, surface processing on films such as an undercoat layer, an antistatic layer, an antihalation layer, a protective layer, etc. Therefore, a coating device is often added. Although each manufacturing process is described briefly below, it is not limited to these.

  First, the prepared cellulose acylate solution (dope) is casted on a drum or band when a cellulose acylate film is produced by a solvent cast method, and the solvent is evaporated to form a film. It is preferable to adjust the concentration of the dope before casting so that the solid content is 5 to 40% by mass. The surface of the drum or band is preferably finished in a mirror state. The dope is preferably cast on a drum or band having a surface temperature of 30 ° C. or lower, and particularly preferably a metal support temperature of −10 to 20 ° C. Further, JP 2000-301555, JP 2000-301558, JP 07-032391, JP 03-193316, JP 05-086212, JP 62-037113, JP 02-276607. The methods described in JP-A Nos. 55-014201, 02-111511, and 02-208650 can be used in the present invention.

(Multilayer casting)
The cellulose acylate solution may be cast as a single layer liquid on a smooth band or drum as a metal support, or a plurality of cellulose acylate liquids of two or more layers may be cast. When casting a plurality of cellulose acylate solutions, produce a film while casting and laminating a solution containing cellulose acylate from a plurality of casting openings provided at intervals in the traveling direction of the metal support. For example, the methods described in JP-A-61-158414, JP-A-1-122419, and JP-A-11-198285 can be applied. Alternatively, a film may be formed by casting a cellulose acylate solution from two casting ports. For example, JP-B-60-27562, JP-A-61-94724, JP-A-61-947245, It can be carried out by the methods described in JP-A Nos. 61-104813, 61-158413, and 6-134933. Further, a cellulose acylate film in which a flow of a high-viscosity cellulose acylate solution described in JP-A-56-162617 is wrapped with a low-viscosity cellulose acylate solution, and the high- and low-viscosity cellulose acylate solutions are simultaneously extruded. A casting method may be used. Furthermore, it is also a preferable aspect that the outer solution described in JP-A-61-94724 and JP-A-61-94725 contains a larger amount of an alcohol component which is a poor solvent than the inner solution. Alternatively, by using two casting ports, peeling the film formed on the metal support by the first casting port, and performing the second casting on the side that was in contact with the metal support surface, A film may be produced, for example, a method described in Japanese Patent Publication No. 44-20235. The cellulose acylate solution to be cast may be the same solution or different cellulose acylate solutions, and is not particularly limited. In order to give a function to a plurality of cellulose acylate layers, a cellulose acylate solution corresponding to the function may be extruded from each casting port. Furthermore, the cellulose acylate solution can be cast by simultaneously casting other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing layer).

  In the conventional single-layer liquid, it is necessary to extrude a high-concentration and high-viscosity cellulose acylate solution in order to obtain the required film thickness. In many cases, this causes a problem such as a fault or flatness. As a solution to this, by casting a plurality of cellulose acylate solutions from a casting port, a highly viscous solution can be extruded onto a metal support at the same time. Not only can it be produced, but also the use of a concentrated cellulose acylate solution can reduce the drying load and increase the film production speed. In the case of co-casting, the inner and outer thicknesses are not particularly limited, but preferably the outer side is preferably 1 to 50% of the total film thickness, and more preferably 2 to 30%. Here, in the case of co-casting with three or more layers, the total thickness of the layer in contact with the metal support and the layer in contact with the air side is defined as the outer thickness. In the case of co-casting, a cellulose acylate film having a laminated structure can be produced by co-casting cellulose acylate solutions having different additive concentrations such as the above-mentioned plasticizer, ultraviolet absorber and matting agent. For example, a cellulose acylate film having a structure of skin layer / core layer / skin layer can be produced. For example, the matting agent can be contained in the skin layer in a large amount or only in the skin layer. The plasticizer and the ultraviolet absorber can be contained in the core layer more than the skin layer, and may be contained only in the core layer. It is also possible to change the type of plasticizer and ultraviolet absorber between the core layer and the skin layer. For example, the skin layer contains at least one of a low-volatile plasticizer and an ultraviolet absorber, and the core layer is made plastic. It is also possible to add an excellent plasticizer or an ultraviolet absorber excellent in ultraviolet absorption. Moreover, it is also a preferable aspect to contain a peeling accelerator only in the skin layer on the metal support side. It is also preferable to add more alcohol, which is a poor solvent, to the skin layer than the core layer in order to cool the metal support by the cooling drum method to gel the solution. The Tg of the skin layer and the core layer may be different, and the Tg of the core layer is preferably lower than the Tg of the skin layer. Further, the viscosity of the solution containing cellulose acylate during casting may be different between the skin layer and the core layer, and the viscosity of the skin layer is preferably smaller than the viscosity of the core layer. It may be smaller than the viscosity.

(Casting)
As a solution casting method, a method in which the prepared dope is uniformly extruded from a pressure die onto a metal support, and a method using a doctor blade in which the dope once cast on the metal support is adjusted with a blade is used. Alternatively, there is a method using a reverse roll coater that adjusts with a reverse rotating roll, and a method using a pressure die is preferable. The pressure die includes a coat hanger type and a T die type, and any of them can be preferably used. In addition to the methods listed here, it can be carried out by various methods of casting a cellulose triacetate solution known in the art, and by setting each condition in consideration of differences in the boiling point of the solvent used, etc. The same effects as those described in the above publication can be obtained. The endlessly running metal support used for producing the cellulose acylate film according to the present invention includes a drum whose surface is mirror-finished by chrome plating and a stainless steel belt whose surface is mirror-finished by surface polishing (referred to as a band). May be used). One or two or more pressure dies used for producing the cellulose acylate film according to the present invention may be installed above the metal support. Preferably 1 or 2 groups. When two or more units are installed, the amount of dope to be cast may be divided into various ratios for each die, or the dope may be fed to the dies from each of a plurality of precision quantitative gear pumps. The temperature of the cellulose acylate solution used for casting is preferably −10 to 55 ° C., more preferably 25 to 50 ° C. In that case, all of the steps may be the same or may be different at different points in the step. If they are different, it may be a desired temperature just before casting.

(Dry)
The drying of the dope on the metal support involved in the production of the cellulose acylate film is generally performed by applying hot air from the surface side of the metal support (drum or belt), that is, the surface of the web on the metal support, A method of applying hot air from the back of the drum or belt, contacting the temperature-controlled liquid from the back of the belt or drum opposite the dope casting surface, and heating the drum or belt by heat transfer to control the surface temperature Although there is a heat transfer method, the back surface liquid heat transfer method is preferable. The surface temperature of the metal support before casting may be any number as long as it is not higher than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the metal support, the temperature should be set to 1 to 10 ° C. lower than the boiling point of the lowest boiling solvent used. Is preferred. This is not the case when the cast dope is cooled and peeled off without drying.

(Extension process)
The retardation of the cellulose acylate film according to the present invention can be adjusted by stretching. Furthermore, there is also a method of positively stretching in the width direction. -48271, and the like. This stretches the produced film in order to increase the in-plane retardation value of the cellulose acylate film.
The film is stretched at room temperature or under heating conditions. The heating temperature is preferably not higher than the glass transition temperature of the film. The stretching of the film may be uniaxial stretching only in the longitudinal or lateral direction, or may be simultaneous or sequential biaxial stretching. Stretching is performed by 1 to 200%. The stretching is preferably 1 to 100%, particularly preferably 1 to 50%. The birefringence of the optical film is preferably such that the refractive index in the width direction is larger than the refractive index in the length direction. Therefore, it is preferable to stretch more in the width direction. In addition, the stretching process may be performed in the middle of the film forming process, or the raw film that has been formed and wound may be stretched. In the former case, the stretching may be performed in a state including the residual solvent amount, and the stretching can be preferably performed at a residual solvent amount of 2 to 30%.

The film thickness of the cellulose acylate film relating to the present invention obtained after drying varies depending on the purpose of use and is usually preferably in the range of 5 to 500 μm, more preferably in the range of 20 to 300 μm, particularly preferably in the range of 30 to 150 μm. . Moreover, it is preferable that it is 40-110 micrometers for optical uses, especially for VA liquid crystal display devices. The film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the metal support speed, and the like so as to obtain a desired thickness. The width of the cellulose acylate film obtained as described above is preferably 0.5 to 3 m, more preferably 0.6 to 2.5 m, still more preferably 0.8 to 2.2 m. The length is preferably 100 to 10,000 m per roll, more preferably 500 to 7000 m, and still more preferably 1000 to 6000 m. When winding, knurling is preferably applied to at least one end, the width is preferably 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is preferably 0.5 to 500 μm, more preferably 1 to 200 μm. This may be a single push or a double push.
The variation in the Re ₍₅₉₀₎ value of the full width is preferably ± 5 nm, and more preferably ± 3 nm. Further, the variation of the Rth ₍₅₉₀₎ value is preferably ± 10 nm, and more preferably ± 5 nm. Further, it is preferable that the variation in the Re value and the Rth value in the length direction is also within the range of the variation in the width direction.

(Optical properties of cellulose acylate film)
The optical properties of the cellulose acylate film according to the present invention preferably satisfy the following formulas (I) and (II) in order to widen the viewing angle of a liquid crystal display device, particularly a VA mode liquid crystal display device. In particular, it is preferable when a cellulose acylate film is used for the protective film on the liquid crystal cell side of the polarizing plate.
Formula (I): 20 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm,
Formula (II): 70 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm
In the present invention, the Re / Rth ratio is preferably adjusted to 0.1 to 0.8. More preferably, it is adjusted to 0.25 to 0.6. These adjustments can be made according to the type of additive, the amount added, and the draw ratio.
In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at a wavelength λ, respectively. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments). Rth (λ) is light having a wavelength of λ nm from the direction inclined by + 40 ° with respect to the normal direction of the film, with Re (λ) and the in-plane slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis). And a retardation value measured by injecting light having a wavelength of λ nm from a direction tilted by −40 ° with respect to the normal direction of the film with the in-plane slow axis as the tilt axis (rotation axis). KOBRA 21ADH is calculated based on the retardation values measured in three directions in total. Here, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. The average refractive index of cellulose acylate is 1.48. The KOBRA 21ADH calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness.

When the cellulose acylate film according to the present invention is used in the VA mode, a mode in which a total of two sheets are used on each side of the cell (two-sheet type) and a mode in which only one of the upper and lower sides of the cell is used ( There are two types, one sheet type).
In the case of the two-sheet type, Re is preferably 20 to 100 nm, and more preferably 30 to 70 nm. Rth is preferably 70 to 300 nm, more preferably 100 to 200 nm.
In the case of a single sheet type, Re is preferably 30 to 150 nm, and more preferably 40 to 100 nm. Rth is preferably from 100 to 300 nm, more preferably from 150 to 250 nm.

  The variation of the slow axis angle in the film plane of the cellulose acylate film according to the present invention is preferably in the range of -2 to +2 degrees with respect to the reference direction of the roll film, and in the range of -1 to +1 degrees. More preferably, it is in the range of -0.5 degree to +0.5 degree. Here, the reference direction is the longitudinal direction of the roll film when the cellulose acylate film is longitudinally stretched, and the width direction of the roll film when laterally stretched.

In the cellulose acylate film according to the present invention, the difference ΔRe (= Re10% RH−Re80% RH) between the Re value at 25 ° C. and 10% RH and the Re value at 25 ° C. and 80% RH is 0 to 10 nm. The difference ΔRth (= Rth10% RH−Rth80% RH) between the Rth value at 10 ° C. at 10 ° C. and the Rth value at 80% RH at 25 ° C. is 0 to 30 nm. This is preferable.
In addition, the cellulose acylate film according to the present invention preferably has an equilibrium water content of not more than 3.2% at 25 ° C. and 80% RH in order to reduce the color change with time of the liquid crystal display device.
The moisture content is measured by measuring a cellulose acylate film sample 7 mm × 35 mm according to the present invention by a Karl Fischer method using a moisture meter and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). . It is calculated by dividing the amount of water (g) by the sample mass (g).

The cellulose acylate film according to the present invention is liquid crystal having a moisture permeability of 60 ° C., 95% RH, 24 hr (film thickness 80 μm conversion) of 400 g / m ² · 24 hr to 1800 g / m ² · 24 hr. This is preferable for reducing the color change of the display device over time.
If the film thickness of the cellulose acylate film is thick, the moisture permeability becomes small, and if the film thickness is thin, the moisture permeability becomes large. Therefore, it is necessary to convert the sample of any film thickness to a standard of 80 μm. Conversion of the film thickness is obtained as (water vapor permeability in terms of 80 μm = measured moisture permeability × measured film thickness μm / 80 μm).
The measurement method of moisture permeability is “Polymer Properties II” (Polymer Experiment Course 4, Kyoritsu Shuppan), pages 285-294: Measurement of vapor permeation (mass method, thermometer method, vapor pressure method, adsorption amount method) The method described in can be applied.
The glass transition temperature was measured by adjusting a cellulose acylate film sample (unstretched) 5 mm × 30 mm according to the present invention at 25 ° C. and 60% RH for 2 hours or more, and then measuring the dynamic viscoelasticity (Vibron: DVA-225 ( Measured by a distance between grips of 20 mm, a heating rate of 2 ° C./min, a measurement temperature range of 30 ° C. to 200 ° C., and a frequency of 1 Hz, and the vertical axis is the logarithmic axis and the storage elastic modulus, When the temperature (° C) is taken as the linear axis on the horizontal axis, the straight line 1 is drawn in the solid region to draw the straight line 1 in the solid region, and the storage elastic modulus shifts from the solid region to the glass transition region. When the straight line 2 is drawn in the region, the intersection of the straight line 1 and the straight line 2 is a temperature at which the storage elastic modulus suddenly decreases and the film starts to soften when the temperature rises, and the temperature starts to move to the glass transition region. Glass Was the transition temperature Tg (dynamic viscoelasticity).
In addition, the cellulose acylate film according to the present invention preferably has a haze of 0.01 to 2%. Here, the haze can be measured as follows.
The haze is measured by measuring a cellulose acylate film sample 40 mm × 80 mm according to the present invention at 25 ° C. and 60% RH with a haze meter (HGM-2DP, Suga Test Instruments) according to JIS K-6714.
The cellulose acylate film according to the present invention preferably has a mass change of 0 to 5% when left for 48 hours under conditions of 80 ° C. and 90% RH.
In addition, the cellulose acylate film according to the present invention has a dimensional change when left for 24 hours under conditions of 60 ° C. and 95% RH, and a size when left for 24 hours under conditions of 90 ° C. and 5% RH. The degree change is preferably 0 to 5%.
It is preferable that the photoelastic coefficient is 50 × 10 ⁻¹³ cm ² / dyne or less in order to reduce the color change with time of the liquid crystal display device.
As a specific measuring method, a tensile stress is applied to the major axis direction of a 10 mm × 100 mm cellulose acylate film sample, and the retardation at that time is measured with an ellipsometer (M150, JASCO Corporation). The photoelastic coefficient is calculated from the amount of change in retardation with respect to.

(Optically anisotropic layer)
Further, the protective film may be a polymer film provided with an optically anisotropic layer. The optically anisotropic layer preferably has an alignment layer and an optically anisotropic layer in this order on a transparent polymer film.

  The alignment layer can be provided by means such as a rubbing treatment of an organic compound (preferably a polymer), oblique deposition of an inorganic compound, or formation of a layer having a microgroup. Furthermore, an alignment layer in which an alignment function is generated by application of an electric field, application of a magnetic field or light irradiation is also known, but an alignment layer formed by a rubbing treatment of a polymer is particularly preferable. The rubbing treatment is preferably performed by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth. It is preferable that the absorption axis direction and the rubbing direction of the polarizer are substantially parallel. As the polymer used for the alignment layer, polyimide, polyvinyl alcohol, a polymer having a polymerizable group described in JP-A-9-152509, and the like can be preferably used. The thickness of the alignment layer is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

  The optically anisotropic layer preferably contains a liquid crystalline compound. The liquid crystal compound used in the present invention particularly preferably has a discotic compound (discotic liquid crystal). The discotic liquid crystal molecule has a disk-like core portion like the triphenylene derivative of D-1, and has a structure in which side chains extend radially therefrom. In order to impart stability over time, it is also preferable to further introduce a group that reacts with heat, light or the like. Preferred examples of the discotic liquid crystal are described in JP-A-8-50206.

  The discotic liquid crystal molecules are aligned almost parallel to the film plane with a pretilt angle in the rubbing direction in the vicinity of the alignment layer, and the discotic liquid crystal molecules are oriented so that they are perpendicular to the plane on the opposite air side. is doing. The discotic liquid crystal layer as a whole has a hybrid alignment, and this layer structure can realize a wide viewing angle of a TN mode TFT-LCD.

  The optically anisotropic layer is generally a discotic compound and another compound (for example, a polymerizable monomer, a photopolymerization initiator) dissolved in a solvent, coated on the alignment layer, dried, and then discotic nematic. After heating to the phase formation temperature, it is obtained by polymerization by irradiation with UV light or the like and further cooling. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound used in the present invention is preferably 70 to 300 ° C, particularly preferably 70 to 170 ° C.

In addition to the discotic compound added to the optically anisotropic layer, the compound has compatibility with the discotic compound and can give a preferable change in tilt angle to the liquid crystalline discotic compound or inhibit the alignment. Any compound can be used as long as it is not. Among these, additives for controlling the orientation on the air interface side such as polymerizable monomers (eg, compounds having vinyl group, vinyloxy group, acryloyl group and methacryloyl group), fluorine-containing triazine compounds, cellulose acetate, cellulose acetate Mention may be made of polymers such as pionate, hydroxypropylcellulose and cellulose acetate butyrate. These compounds are generally used in an amount of 0.1 to 50% by mass, preferably 0.1 to 30% by mass, based on the discotic compound.
The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

The optically anisotropic layer may be a non-liquid crystalline polymer layer prepared by dissolving a non-liquid crystalline compound in a solvent, applying the solution onto a support, and drying by heating. In this case, for example, the non-liquid crystalline compound is excellent in heat resistance, chemical resistance, transparency, and has high rigidity, so polyamide, polyimide, polyester, polyether ketone, polyaryl ether ketone, polyamide imide, polyester imide, etc. These polymers can be used. Any one of these polymers may be used alone, or a mixture of two or more having different functional groups such as a mixture of polyaryletherketone and polyamide may be used. . Among such polymers, polyimide is preferable because of its high transparency, high orientation, and high stretchability. Moreover, as a support body, a TAC film is preferable.
Moreover, it is also preferable that the laminate of the non-liquid crystal layer and the support is stretched 1.05 times in the tenter horizontal axis and the support side is bonded to the polarizer.
Furthermore, the optically anisotropic layer may be an alignment solidified layer of cholesteric liquid crystal having a selective reflection wavelength region of 350 nm or less. Examples of the cholesteric liquid crystal are described in JP-A-3-67219, JP-A-3-140921, JP-A-5-61039, JP-A-6-186534, JP-A-9-133810, and the like. Any suitable material showing the selective reflection characteristics can be used. What can be preferably used from the viewpoint of the stability of the alignment solidified layer is, for example, a cholesteric liquid crystal composed of a cholesteric liquid crystal polymer, a nematic liquid crystal polymer containing a chiral agent, a compound that forms such a liquid crystal polymer by polymerization treatment with light, heat, or the like. A layer can be formed.
In this case, the optically anisotropic layer can be formed by, for example, a method of coating a cholesteric liquid crystal on a support substrate. In that case, for the purpose of controlling the phase difference or the like, a method of overcoating the same type or different types of cholesteric liquid crystals may be employed as necessary. For the coating treatment, for example, an appropriate method such as a gravure method, a die method, or a dipping method can be adopted. An appropriate material such as a TAC film or other polymer film can be used as the support substrate.
In the above, when forming the optically anisotropic layer, a means for aligning the liquid crystal is employed. The alignment means is not particularly limited, and any appropriate means that can align the liquid crystal compound can be adopted. Incidentally, as an example, there is a method in which liquid crystal is coated on the alignment film and aligned. As the alignment film, a rubbing treatment film made of an organic compound such as a polymer, an oblique deposition film of an inorganic compound, a film having a microgroove, or an organic material such as ω-tricosanoic acid, dioctadecylmethylammonium chloride, or methyl stearylate. Examples thereof include a film obtained by accumulating LB films by the Langmuir-Blodgett method of compounds.
Further examples include an alignment film that generates an alignment function by light irradiation. On the other hand, a method of aligning liquid crystal on a stretched film (Japanese Patent Application Laid-Open No. 3-9325), a method of aligning liquid crystal under application of an electric field or magnetic field, and the like are also included. The alignment state of the liquid crystal is preferably as uniform as possible, and is preferably a solidified layer fixed in the alignment state.

When the cellulose acylate film according to the present invention is used as a polarizing plate protective film, the method for producing the polarizing plate is not particularly limited, and can be produced by a general method. For example, there is a method in which the obtained cellulose acylate film is treated with an alkali and bonded to both sides of a polarizer produced by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Examples of the adhesive used to bond the protective film-treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like. The polarizing plate is composed of a polarizer and a protective film that protects both surfaces of the polarizer, and a protective film may be bonded to one surface of the polarizing plate and a separate film may be bonded to the opposite surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal cell. Moreover, a separate film is used in order to cover the contact bonding layer bonded to a liquid crystal cell, and is used for the surface side which bonds a polarizing plate to a liquid crystal cell.
The cellulosic acylate film relating to the present invention is preferably bonded to the polarizer so that the transmission axis of the polarizer coincides with the slow axis of the cellulose acylate film relating to the present invention.
In addition, the polarizing plate produced under polarizing plate crossed Nicol, when the accuracy of orthogonality between the slow axis of the cellulose acylate film according to the present invention and the absorption axis of the polarizer (axis orthogonal to the transmission axis) is greater than 1 °, Polarization degree performance under a polarizing plate crossed Nicole is reduced, light leakage occurs, and when combined with a liquid crystal cell, a sufficient black level and contrast cannot be obtained, so the main refractive index of the cellulose acylate film according to the present invention The deviation between the direction of nx and the direction of the transmission axis of the polarizing plate is preferably within 1 °, preferably within 0.5 °.

(surface treatment)
The cellulose acylate film according to the present invention can achieve improved adhesion between the cellulose acylate film and each functional layer (for example, the undercoat layer and the back layer) by optionally performing a surface treatment. As the surface treatment, for example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs in a low-pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferable. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Regarding these, the details are disclosed in the Invention Association Public Technical Bulletin No. 2001-1745 (issued March 15, 2001, Invention Association) p. 30-32. Note that, in the plasma treatment at atmospheric pressure which has been attracting attention in recent years, for example, irradiation energy of 20 to 500 Kgy is used under 10 to 1000 Kev, and more preferably irradiation energy of 20 to 300 Kgy is used under 30 to 500 Kev. Among these, an alkali saponification treatment is particularly preferable, and it is extremely effective as a surface treatment of a cellulose acylate film.

  The alkali saponification treatment is preferably carried out by a method in which the cellulose acylate film is directly immersed in a saponification solution tank or a method in which the saponification solution is applied to the cellulose acylate film. Examples of the coating method include a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, and an E-type coating method. The solvent of the alkali saponification coating solution has good wettability in order to apply the saponification solution to the cellulose acylate film, and the surface of the cellulose acylate film surface is not formed by the saponification solution solvent. It is preferred to select a solvent that remains good. Specifically, an alcohol solvent is preferable, and isopropyl alcohol is particularly preferable. An aqueous solution of a surfactant can also be used as a solvent. The alkali of the alkali saponification coating solution is preferably an alkali that dissolves in the above solvent, and more preferably KOH or NaOH. The pH of the saponification coating solution is preferably 10 or more, more preferably 12 or more. The reaction conditions during alkali saponification are preferably 1 second to 5 minutes at room temperature, more preferably 5 seconds to 5 minutes, and particularly preferably 20 seconds to 3 minutes. After the alkali saponification reaction, it is preferable to wash the surface on which the saponification solution is applied with water or with an acid and then with water.

  In the polarizing plate of the present invention, it is preferable that at least one layer of a hard coat layer, an antiglare layer and an antireflection layer is provided on the surface of the protective film on the other side of the polarizing plate. That is, when the polarizing plate is used for a liquid crystal display device, it is preferable to provide a functional film such as an antireflection layer on the protective film (TAC2) disposed on the side opposite to the liquid crystal cell. It is preferable to provide at least one of a layer, an antiglare layer, and an antireflection layer. Each layer does not need to be provided as a separate layer. For example, the antiglare layer functions as an antireflection layer and an antiglare layer by providing the antireflection layer and the hard coat layer with the function. May be provided. (Figure 1)

(Antireflection layer)
In the present invention, at least the light scattering layer and the low refractive index layer are laminated in this order on the protective film, or the intermediate refractive index layer, the high refractive index layer, and the low refractive index layer are arranged in this order on the protective film. The antireflection layer laminated with is preferably used. Preferred examples thereof are described below.

A preferred example of an antireflection layer in which a light scattering layer and a low refractive index layer are provided on a protective film will be described.
In the light scattering layer, mat particles are preferably dispersed, and the refractive index of the material other than the mat particles in the light scattering layer is preferably in the range of 1.50 to 2.00, and the low refractive index The refractive index of the layer is preferably in the range of 1.20 to 1.49. In the present invention, the light scattering layer has both antiglare properties and hard coat properties, and may be a single layer or a plurality of layers, for example, 2 to 4 layers.

The antireflection layer has an uneven surface shape with a center line average roughness Ra of 0.08 to 0.40 μm, a 10-point average roughness Rz of 10 times or less of Ra, an average mountain valley distance Sm of 1 to 100 μm, and an uneven depth. Designed so that the standard deviation of the height of the convex part from the part is 0.5 μm or less, the standard deviation of the average mountain valley distance Sm with respect to the center line is 20 μm or less, and the surface with the inclination angle of 0 to 5 degrees is 10% or more. By doing so, sufficient anti-glare properties and a visually uniform matte feeling are achieved, which is preferable. Further, the ratio of the minimum value and the maximum value of the reflectance within the range of a ^* value −2 to 2, b ^* value −3 to 3, and 380 nm to 780 nm under the light source C is 0.5. By being -0.99, the color of reflected light becomes neutral, which is preferable. Moreover, it is preferable that the b ^* value of the transmitted light under the C light source is 0 to 3 because the yellow color of white display when applied to a display device is reduced. In addition, when a 120 μm × 40 μm grid is inserted between the surface light source and the antireflection film of the present invention and the luminance distribution is measured on the film, the standard deviation of the luminance distribution is 20 or less. The glare when applying the film of the present invention is reduced, which is preferable.

  The antireflective layer that can be used in the present invention suppresses reflection of external light by setting its optical characteristics to a specular reflectance of 2.5% or less, a transmittance of 90% or more, and a 60 degree gloss of 70% or less. This is preferable because visibility is improved. In particular, the specular reflectance is more preferably 1% or less, and most preferably 0.5% or less. Haze 20% to 50%, ratio of internal haze / total haze value 0.3 to 1, haze value after formation of low refractive index layer from haze value up to light scattering layer within 15%, comb width 0 .Transmission image sharpness at 5 mm to 20% to 50%, vertical transmission light / transmittance ratio of 2 degrees from vertical to 1.5 to 5.0, preventing glare on a high-definition LCD panel, Reduction of blurring of characters and the like is achieved, which is preferable.

(Low refractive index layer)
The refractive index of the low refractive index layer that can be used in the present invention is preferably 1.20 to 1.49, more preferably 1.30 to 1.44. Further, the low refractive index layer preferably satisfies the following formula from the viewpoint of reducing the reflectance.
(M / 4) λ × 0.7 <n1d1 <(m / 4) λ × 1.3
In the formula, m is a positive odd number, n1 is the refractive index of the low refractive index layer, and d1 is the film thickness (nm) of the low refractive index layer. Further, λ is a wavelength, which is a value in the range of 500 to 550 nm.

The material for forming the low refractive index layer will be described below.
The low refractive index layer preferably contains a fluorine-containing polymer as a low refractive index binder. The fluorine polymer is preferably a fluorine-containing polymer that is crosslinked by heat or ionizing radiation having a coefficient of dynamic friction of 0.03 to 0.20, a contact angle with water of 90 to 120 °, and a sliding angle of pure water of 70 ° or less. When the polarizing plate of the present invention is mounted on an image display device, the lower the peel strength from a commercially available adhesive tape, the easier it is to peel off after sticking a sticker or memo, preferably 500 gf or less when measured with a tensile tester. 300 gf or less is more preferable, and 100 gf or less is most preferable. Further, the higher the surface hardness measured with a microhardness meter, the harder it is to scratch, preferably 0.3 GPa or more, more preferably 0.5 GPa or more.

  Examples of the fluorine-containing polymer used in the low refractive index layer include dehydration condensates subsequent to hydrolysis of perfluoroalkyl group-containing silane compounds (for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane). In addition, a fluorine-containing copolymer having a fluorine-containing monomer unit and a structural unit for imparting crosslinking reactivity as constituent components can be mentioned.

  Specific examples of the fluorine-containing monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, perfluorooctylethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc. ), A part of (meth) acrylic acid or a fully fluorinated alkyl ester derivative (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) or M-2020 (manufactured by Daikin)), a complete or partially fluorinated vinyl ether, and the like. Perfluoroolefins are preferred, and hexafluoropropylene is particularly preferred from the viewpoints of refractive index, solubility, transparency, availability, and the like.

  As structural units for imparting crosslinking reactivity, structural units obtained by polymerization of monomers having a self-crosslinkable functional group in the molecule in advance such as glycidyl (meth) acrylate and glycidyl vinyl ether, carboxyl groups, hydroxy groups, amino acids Polymerization of monomers having a group, a sulfo group, etc. (eg (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, maleic acid, crotonic acid, etc.) The resulting structural unit, a structural unit in which a crosslinking reactive group such as a (meth) acryloyl group is introduced into these structural units by a polymer reaction (for example, an acrylic acid chloride is allowed to act on a hydroxy group). And the like.

  In addition to the above-mentioned fluorine-containing monomer units and structural units for imparting crosslinking reactivity, monomers not containing fluorine atoms can be copolymerized as appropriate from the viewpoints of solubility in solvents and film transparency. There are no particular limitations on the monomer units that can be used in combination. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid 2) -Ethylhexyl), methacrylates (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl) Vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate etc.), acrylamides (N-tert-butylacrylamide, N- Black hexyl acrylamide), methacrylamides, and acrylonitrile derivatives.

  As described in JP-A-10-25388 and JP-A-10-147739, a curing agent may be appropriately used in combination with the above polymer.

(Light scattering layer)
The light scattering layer is formed for the purpose of imparting to the film a light diffusibility due to at least one of surface scattering and internal scattering and a hard coat property for improving the scratch resistance of the film. Therefore, it is formed to contain a binder for imparting hard coat properties, matte particles for imparting light diffusibility, and inorganic fillers for increasing the refractive index, preventing cross-linking shrinkage, and increasing the strength as necessary. The Further, by providing such a light scattering layer, the light scattering layer also functions as an antiglare layer, and the polarizing plate has an antiglare layer.

  The thickness of the light scattering layer is preferably 1 to 10 μm and more preferably 1.2 to 6 μm for the purpose of imparting hard coat properties. If it is too thin, the hard property will be insufficient, and if it is too thick, curling and brittleness will deteriorate and the workability will be insufficient.

  The binder of the light scattering layer is preferably a polymer having a saturated hydrocarbon chain or a polyether chain as the main chain, and more preferably a polymer having a saturated hydrocarbon chain as the main chain. The binder polymer preferably has a crosslinked structure. As the binder polymer having a saturated hydrocarbon chain as a main chain, a polymer of an ethylenically unsaturated monomer is preferable. As the binder polymer having a saturated hydrocarbon chain as the main chain and having a crosslinked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable. In order to make the binder polymer have a high refractive index, the monomer structure contains an aromatic ring, at least one atom selected from halogen atoms other than fluorine, sulfur atoms, phosphorus atoms, and nitrogen atoms. You can also choose.

  Examples of the monomer having two or more ethylenically unsaturated groups include esters of polyhydric alcohol and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di ( (Meth) acrylate, 1,4-cyclohexanediacrylate, pentaerythritol tetra (meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol Tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-si Rhohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), modified ethylene oxide, vinylbenzene and derivatives thereof (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1, 4-divinylcyclohexanone), vinyl sulfone (eg, divinyl sulfone), acrylamide (eg, methylenebisacrylamide) and methacrylamide. Two or more of these monomers may be used in combination.

  Specific examples of the high refractive index monomer include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide, 4-methacryloxyphenyl-4′-methoxyphenyl thioether, and the like. Two or more of these monomers may be used in combination.

Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.
Therefore, a coating liquid containing a monomer having an ethylenically unsaturated group, a photo radical initiator or a thermal radical initiator, mat particles, and an inorganic filler is prepared, and the coating liquid is applied onto a protective film and then ionizing radiation or heat. It can be cured by a polymerization reaction to form an antireflection film. As these photo radical initiators, known ones can be used.

The polymer having a polyether as the main chain is preferably a ring-opening polymer of a polyfunctional epoxy compound. The ring-opening polymerization of the polyfunctional epoxy compound can be performed by irradiation with ionizing radiation or heating in the presence of a photoacid generator or a thermal acid generator.
Therefore, a coating solution containing a polyfunctional epoxy compound, a photoacid generator or a thermal acid generator, matte particles and an inorganic filler is prepared, and the coating solution is applied on a protective film and then cured by ionizing radiation or heat polymerization reaction. Thus, an antireflection film can be formed.

Instead of or in addition to a monomer having two or more ethylenically unsaturated groups, a monomer having a crosslinkable functional group is used to introduce a crosslinkable functional group into the polymer, and by reaction of this crosslinkable functional group, A crosslinked structure may be introduced into the binder polymer.
Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, in the present invention, the crosslinkable functional group may not react immediately but may exhibit reactivity as a result of decomposition.
These binder polymers having a crosslinkable functional group can form a crosslinked structure by heating after coating.

For the purpose of imparting antiglare properties, the light scattering layer contains matte particles having an average particle size of 1 to 10 μm, preferably 1.5 to 7.0 μm, such as inorganic compound particles or resin particles, for the purpose of imparting antiglare properties. Is done.
As specific examples of the mat particles, inorganic particles such as silica particles and TiO ₂ particles; resin particles such as acrylic particles, cross-linked acrylic particles, polystyrene particles, cross-linked styrene particles, melamine resin particles, and benzoguanamine resin particles are preferable. Can be mentioned. Of these, crosslinked styrene particles, crosslinked acrylic particles, crosslinked acrylic styrene particles, and silica particles are preferable. The shape of the mat particles can be either spherical or irregular.

  Two or more kinds of mat particles having different particle diameters may be used in combination. It is possible to impart anti-glare properties with mat particles having a larger particle size and to impart other optical characteristics with mat particles having a smaller particle size.

  Furthermore, the particle size distribution of the mat particles is most preferably monodisperse, and the particle sizes of the particles are preferably closer to each other. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less, more preferably 0.1% of the total number of particles. Or less, more preferably 0.01% or less. Matt particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and a matting agent having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification.

The mat particles are contained in the light scattering layer so that the amount of mat particles in the formed light scattering layer is preferably 10 to 1000 mg / m ² , more preferably 100 to 700 mg / m ² .
The particle size distribution of the mat particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

The light scattering layer is made of an oxide of at least one metal selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, in addition to the above mat particles, in order to increase the refractive index of the layer. Thus, it is preferable that an inorganic filler having an average particle size of 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.06 μm or less is contained.
Conversely, in order to increase the refractive index difference from the mat particles, it is also preferable to use a silicon oxide in order to keep the refractive index of the layer low in the light scattering layer using the high refractive index mat particles. The preferred particle size is the same as that of the aforementioned inorganic filler.
Specific examples of the inorganic filler to be used in the light scattering _{layer, TiO 2, ZrO 2, Al} 2 O 3, In 2 O 3, ZnO, SnO 2, Sb 2 O 3, ITO and SiO ₂ and the like. TiO ₂ and ZrO ₂ are particularly preferable from the viewpoint of increasing the refractive index. The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.
The amount of these inorganic fillers added is preferably 10 to 90% of the total mass of the light scattering layer, more preferably 20 to 80%, and particularly preferably 30 to 75%.
In addition, since such a filler has a particle size sufficiently smaller than the wavelength of light, scattering does not occur, and a dispersion in which the filler is dispersed in a binder polymer behaves as an optically uniform substance.

  The bulk refractive index of the mixture of binder and inorganic filler in the light scattering layer is preferably 1.50 to 2.00, more preferably 1.51 to 1.80. In order to make the refractive index within the above range, the kind and amount ratio of the binder and the inorganic filler may be appropriately selected. How to select can be easily known experimentally in advance.

  In order to ensure surface uniformity such as uneven coating, uneven drying, point defects, etc., the light scattering layer should be coated with either a fluorine-based surfactant or a silicone-based surfactant, or both for forming the light scattering layer. Contained in the composition. In particular, a fluorine-based surfactant is preferably used because an effect of improving surface defects such as coating unevenness, drying unevenness, and point defects of the antireflection film of the present invention appears in a smaller addition amount. The purpose is to increase productivity by giving high-speed coating suitability while improving surface uniformity.

Next, an antireflection layer in which a middle refractive index layer, a high refractive index layer, and a low refractive index layer are laminated in this order on the protective film will be described.
The antireflection layer comprising at least a middle refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) in order on the protective film is designed to have a refractive index satisfying the following relationship. .
High refractive index layer refractive index> Medium refractive index layer refractive index> Protective film refractive index> Low refractive index layer refractive index A hard coat layer may be provided between the protective film and the medium refractive index layer. . Further, it may comprise a medium refractive index hard coat layer, a high refractive index layer and a low refractive index layer.
Examples thereof include antireflection layers described in JP-A-8-122504, JP-A-8-110401, JP-A-10-300902, JP-A-2002-243906, JP-A-2000-11706, and the like.
Other functions may be imparted to each layer, for example, an antifouling low refractive index layer or an antistatic high refractive index layer (eg, JP-A-10-206603, JP-A-2002). -243906 publication etc.) etc. are mentioned.
The haze of the antireflection layer is preferably 5% or less, more preferably 3% or less. The strength of the film is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K5400.

(High refractive index layer and medium refractive index layer)
The layer having a high refractive index of the antireflection film is composed of a cured film containing at least an inorganic compound fine particle having a high refractive index having an average particle diameter of 100 nm or less and a matrix binder.
Examples of the high refractive index inorganic compound fine particles include inorganic compounds having a refractive index of 1.65 or more, preferably those having a refractive index of 1.9 or more. Examples thereof include oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms.
In order to obtain such fine particles, the surface of the particles is treated with a surface treatment agent (for example, silane coupling agents, etc .: JP-A Nos. 11-295503, 11-153703, 2000-9908). Gazette, anionic compound or organometallic coupling agent: JP 2001-310432 A, a core-shell structure with high refractive index particles as a core (JP 2001-166104 A, etc.), specific dispersion (For example, JP-A-11-153703, US Pat. No. 6,210,858, JP-A-2002-277609, etc.) and the like.
Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films.
More preferable materials include a polyfunctional compound-containing composition having at least two polymerizable groups of at least one of radically polymerizable and cationically polymerizable, a composition containing an organometallic compound containing a hydrolyzable group, And at least one composition selected from compositions containing a partial condensate thereof.
Examples thereof include compounds described in JP-A Nos. 2000-47004, 2001-315242, 2001-31871, and 2001-296401.

A curable film obtained from a colloidal metal oxide obtained from a hydrolyzed condensate of metal alkoxide and a metal alkoxide composition is also preferred. For example, it describes in Unexamined-Japanese-Patent No. 2001-293818.
The refractive index of the high refractive index layer is preferably 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.
The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70. The thickness is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.

(Low refractive index layer)
The low refractive index layer is formed by sequentially laminating on the high refractive index layer. The refractive index of the low refractive index layer is preferably 1.20 to 1.55. More preferably, it is 1.30-1.50.
The low refractive index layer is preferably constructed as an outermost layer having scratch resistance and antifouling properties. As means for greatly improving the scratch resistance, it is effective to impart slipperiness to the surface, and conventionally known thin film layer means such as introduction of silicone or introduction of fluorine can be applied.
The fluorine-containing compound is preferably a compound containing a crosslinkable or polymerizable functional group containing fluorine atoms in the range of 35 to 80% by mass.
For example, paragraph numbers [0018] to [0026] of Japanese Patent Application Laid-Open No. 9-222503, paragraph numbers [0019] to [0030] of Japanese Patent Application Laid-Open No. 11-38202, and paragraph numbers of Japanese Patent Application Laid-Open No. 2001-40284. [0027] to [0028], compounds described in JP-A No. 2000-284102, and the like.
The refractive index of the fluorine-containing compound is preferably 1.35 to 1.50. More preferably, it is 1.36-1.47.
The silicone compound is a compound having a polysiloxane structure, preferably containing a curable functional group or a polymerizable functional group in the polymer chain and having a crosslinked structure in the film. For example, reactive silicone (eg, Silaplane (manufactured by Chisso Corporation), silanol group-containing polysiloxane (Japanese Patent Laid-Open No. 11-258403, etc.) and the like can be mentioned.
The crosslinking or polymerization reaction of at least one of the fluorine-containing polymer having a crosslinking or polymerizable group and the siloxane polymer is performed simultaneously with the application of the coating composition for forming the outermost layer containing a polymerization initiator, a sensitizer, or the like. It is preferable to form the low refractive index layer by light irradiation or heating after coating.
Also preferred is a sol-gel cured film in which an organometallic compound such as a silane coupling agent and a specific fluorine-containing hydrocarbon group-containing silane coupling agent are cured by a condensation reaction in the presence of a catalyst.
For example, a polyfluoroalkyl group-containing silane compound or a partially hydrolyzed condensate thereof (Japanese Patent Laid-Open Nos. 58-142958, 58-147483, 58-147484, Japanese Patent Laid-Open Nos. 9-157582, 11) -106704), silyl compounds containing a poly "perfluoroalkyl ether" group which is a fluorine-containing long chain group (Japanese Patent Application Laid-Open Nos. 2000-117902, 2001-48590, 2002) 53804), and the like.
The low refractive index layer has an average primary particle diameter of 1 to 150 nm such as a filler (for example, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)) as an additive other than the above. Low refractive index inorganic compounds, organic fine particles described in paragraphs [0020] to [0038] of JP-A-11-3820, etc.), silane coupling agents, slip agents, surfactants, and the like can be contained.
When the low refractive index layer is located below the outermost layer, the low refractive index layer may be formed by a vapor phase method (vacuum deposition method, sputtering method, ion plating method, plasma CVD method, etc.). The coating method is preferable because it can be manufactured at a low cost.
The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and most preferably 60 to 120 nm.

(Hard coat layer)
The hard coat layer is provided on the surface of the protective film in order to impart physical strength to the protective film provided with the antireflection layer. In particular, it is preferably provided between the transparent support and the high refractive index layer. The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of a light and / or heat curable compound. The curable functional group in the curable compound is preferably a photopolymerizable functional group. Also, hydrolyzable functional group-containing organometallic compounds and organoalkoxysilyl compounds are preferred.
Specific examples of these compounds are the same as those exemplified for the high refractive index layer. Specific examples of the constituent composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908, and WO 00/46617.
The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described for the high refractive index layer.
The hard coat layer can also serve as an antiglare layer containing particles having an average particle size of 0.2 to 10 μm and imparted with an antiglare function (antiglare function).
The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm.
The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

(Other layers of antireflection layer)
Further, a forward scattering layer, a primer layer, an antistatic layer, an undercoat layer, a protective layer, and the like may be provided.

(Antistatic layer)
In the case of providing an antistatic layer, it is preferable to impart conductivity with a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less. The use of hygroscopic substances, water-soluble inorganic salts, certain surfactants, cationic polymers, anionic polymers, colloidal silica, etc. can give a volume resistivity of 10 ⁻⁸ (Ωcm ⁻³ ). There is a problem that dependency is large, and sufficient conductivity cannot be secured at low humidity. Therefore, a metal oxide is preferable as the conductive layer material. Some metal oxides are colored, but using these metal oxides as the conductive layer material is not preferable because the entire film is colored. Zn, Ti, Sn, Al, In, Si, Mg, Ba, Mo, W, or V can be given as the metal that forms a metal oxide without coloring, and a metal oxide containing these as main components is used. It is preferable. Specific examples include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₃ , WO ₃ , V ₂ O ₅ , or complex oxides thereof. In particular, ZnO, TiO ₂ and SnO ₂ are preferable. Examples of containing different atoms include, for example, additives such as Al and In for ZnO, addition of Sb, Nb and halogen elements for SnO ₂ , and Nb and Ta for TiO ₂ . Addition is effective. Furthermore, as described in Japanese Examined Patent Publication No. 59-6235, a material in which the above metal oxide is attached to other crystalline metal particles or fibrous materials (for example, titanium oxide) may be used. The volume resistance value and the surface resistance value are different physical properties and cannot be simply compared. However, in order to secure a conductivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less in volume resistance, It is sufficient that the layer has a surface resistance value of approximately 10 ⁻¹⁰ (Ω / □) or less, and more preferably 10 ⁻⁸ (Ω / □). The surface resistance value of the conductive layer needs to be measured as a value when the antistatic layer is the outermost layer, and can be measured in the middle of forming the laminated film described in this patent.

(Liquid crystal display device)
The liquid crystal display device of the present invention includes a liquid crystal display device using the polarizing plate of the present invention (first form), a VA mode, OCB mode and TN mode liquid crystal using any one of the polarizing plates of the present invention above and below the cell. It is a VA mode liquid crystal display device (third embodiment) using any one of the display device (second embodiment) and the polarizing plate of the present invention on the backlight side.
That is, the polarizing plate of the present invention is advantageously used for a liquid crystal display device. The polarizing plate of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal, AFLC) Various display modes such as HAN (Hybrid Aligned Nematic) have been proposed. Among these, it can use preferably for VA mode or OCB mode.

In a VA mode liquid crystal cell, rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied.
The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). 176625 (in Japanese Patent Publication No. 176625), and (2) a liquid crystal cell (SID97, Digest of tech. Papers (Proceedings) 28 (1997) 845 in which the VA mode is converted into a multi-domain (for MVA mode) in order to enlarge the viewing angle. ), (3) Liquid crystal cells (n-ASM mode, CPA mode) in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied 58-59 (1998)) and (4) SURVAVAL mode liquid crystal cells (presented at LCD International 98) are included
Examples of the VA mode liquid crystal display device include a liquid crystal cell (VA mode cell) and two polarizing plates (polarizing plates made of TAC1, polarizer and TAC2) arranged on both sides thereof (FIG. 2). . The liquid crystal cell carries a liquid crystal between two electrode substrates.

  The OCB mode liquid crystal cell is a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between an upper portion and a lower portion of the liquid crystal cell. OCB mode liquid crystal cells are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are aligned symmetrically between the upper part and the lower part of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

In another aspect of the transmissive liquid crystal display device of the present invention, a cellulose acylate film according to the present invention is used as a protective film for a polarizing plate disposed between a liquid crystal cell and a polarizer. The above cellulose acylate film may be used only for the protective film (between the liquid crystal cell and the polarizer) of one polarizing plate, or both polarizing plates (between the liquid crystal cell and the polarizer). The cellulose acylate film may be used for the two protective films. For bonding to the liquid crystal cell, the cellulose acylate film (TAC1) according to the present invention is preferably on the VA cell side. When the above cellulose acylate film is used only for the protective film (between the liquid crystal cell and the polarizer) of one polarizing plate, this is the upper polarizing plate (observation side) and the lower polarizing plate (backlight side). Either side can be used and there is no functional problem. However, when used as an upper polarizing plate, it is necessary to provide a functional film on the observation side (upper side) and the production yield may be lowered. It is considered an embodiment.
And what formed both the light source side and the observer side with the polarizing plate of this invention is a liquid crystal display device of 2nd form, and what formed only the light source side with the polarizing plate of this invention is liquid crystal of 3rd form. It is a display device.

  The protective film (TAC2) may be a normal cell rate acylate film. For example, KC4UX2M (40 μm manufactured by Konica Capto Co., Ltd.), KC5UX (60 μm manufactured by Konica Caputo Co., Ltd.), KC80UVSFD (Konica Caputo Co., Ltd.) 80 μm), TD80U (80 μm manufactured by Fuji Photo Film Co., Ltd.), TF80U (80 μm manufactured by Fuji Photo Film Co., Ltd.), and the like, but are not limited thereto.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to an Example.

[Film Formation of Cellulose Acylate Film (Films 1 to 19)]
(Cellulose acylate)
Cellulose acylates having different types of acyl groups and different degrees of substitution described in Table 1 were prepared. This was carried out by adding sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) as a catalyst, adding carboxylic acid as a raw material for the acyl substituent, and carrying out an acylation reaction at 40 ° C. At this time, the kind and substitution degree of the acyl group were adjusted by adjusting the kind and amount of the carboxylic acid. Moreover, it age | cure | ripened at 40 degreeC after acylation. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone. In the table, CAB is an abbreviation for cellulose acetate butyrate (cellulose ester derivative whose acyl group is composed of acetyl group and butyryl group), and CAP is cellulose acetate propionate (acyl group is acetyl group and propionyl group). CTA means cellulose triacetate (a cellulose ester derivative whose acyl group is composed only of an acetyl group).

(Dissolution)
Cellulose acylate listed in Table 1, plasticizer (TPP: triphenyl phosphate, BDP: biphenyl diphenyl phosphate), the following ultraviolet absorbers 1 and 2, the following retardation developing agents 1 and 2, the following mixed solvent, dichloromethane / Methanol (87/13 parts by mass) was added with stirring so that the mass concentration of cotton was 15% by mass, and heated to stir and dissolved. At the same time, 0.05 parts by mass of a matting agent (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) as fine particles was added to 100 parts by mass of cellulose acylate and stirred while heating. The additive amount in Table 1 is the mass of the additive with respect to 100 mass of cotton.

UV absorber 1

UV absorber 2

Retardation expression agent 1

Retardation developer 2

(Casting)
The above dope was cast using a band casting machine. A film peeled off from the band with a residual solvent amount of 25 to 35% by mass was stretched at a stretching ratio of 10% to 30.5% using a tenter under the conditions where the stretching temperature was in the range of about Tg-10 to Tg + 10 ° C. 1), the cellulose acylate films 1 to 19 were formed in the width direction. Table 1 shows the draw ratio of the tenter.
In addition, the measuring method of Tg is as follows. That is, after adjusting a film sample (unstretched) 5 mm × 30 mm at 25 ° C. and 60% RH for 2 hours or more, with a dynamic viscoelasticity measuring apparatus (Vibron: DVA-225 (made by IT Measurement Control Co., Ltd.)) Measured at a distance between grips of 20 mm, a heating rate of 2 ° C./minute, a measurement temperature range of 30 ° C. to 200 ° C. and a frequency of 1 Hz, the vertical axis represents the logarithmic axis, the storage elastic modulus, and the horizontal axis the temperature (° C.). When the storage elastic modulus shifts from the solid region to the glass transition region, the sharp decrease in the storage elastic modulus is drawn with the straight line 1 in the solid region and the straight line 1 with the straight line 2 in the glass transition region. The intersection of the straight lines 2 is the temperature at which the storage elastic modulus suddenly decreases and the film begins to soften when the temperature rises, and is the temperature at which the film begins to move to the glass transition region, and thus is defined as the glass transition temperature Tg (dynamic viscoelasticity). . The Tg of the films described in the examples were all in the range of 110 to 160 ° C. when examined by the above method.
The produced cellulose acylate films (optical compensation sheets) 1 to 19 were conditioned at 25 ° C. and 60% RH for 2 hours or more, and 25 using a birefringence measuring device (KOBRA 21ADH, manufactured by Oji Scientific Instruments). The Re retardation value and the Rth retardation value at a wavelength of 590 nm were measured at 60 ° C. and RH. The results are shown in Table 3.

The hazes of the films obtained in this example are all 0.1 to 0.9, the secondary average particle size of the matting agent is 1.0 μm or less, and left for 48 hours under conditions of 80 ° C. and 90% RH. The mass change was 0-3%. Further, all the samples had a photoelastic coefficient of 50 × 10 ⁻¹³ cm ² / dyne or less.

[Production of protective film with optically anisotropic layer (films 20 to 23)]
[Protective films with optically anisotropic layer 20, 21]
On the cellulose acetate films 20 and 21 prepared in the same manner as described above, 5.2 ml / m ^{2 of the following} composition was applied and dried at 60 ° C. for 10 seconds. The surface of the film was washed with running water for 10 seconds, and air at 25 ° C. was blown to dry the film surface.

(Saponification solution composition)
Isopropyl alcohol 818 parts by weight Water 167 parts by weight Propylene glycol 187 parts by weight Potassium hydroxide 68 parts by weight Surfactant (n-C ₁₆ H ₃₃ O (C ₂ H ₄ O) ₁₀ H) 12 parts by weight

(Formation of alignment film)
On the saponified cellulose acetate films 20 and 21, a coating solution having the following composition was applied at 24 ml / m ² with a # 14 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.
Next, the formed film was rubbed in the direction of 45 ° with the stretching direction of cellulose acetate films 20 and 21 (almost coincident with the slow axis).

(Orientation film coating solution composition)
Modified polyvinyl alcohol (1) 20 parts by weight Water 360 parts by weight Methanol 120 parts by weight Glutaraldehyde (crosslinking agent) 1.0 part by weight

Modified polyvinyl alcohol (1)

(Formation of optically anisotropic layer)
On the alignment film, 91 parts by mass of the following discotic liquid crystalline molecules (I), 9 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), cellulose acetate butyrate (CAB531) −1, manufactured by Eastman Chemical Co., Ltd.) 1.5 parts by mass, photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Co.), sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass Then, a coating solution prepared by dissolving 1.0 part by mass of the following citric acid ester mixture in 214.2 parts by mass of methyl ethyl ketone was applied at a temperature of 25 ° C. with a # 3.6 wire bar coater at 6.2 ml / m ² . . This was attached to a metal frame and heated in a constant temperature bath at 140 ° C. for 2 minutes to align the discotic liquid crystalline molecules. Next, using a 120 W / cm high-pressure mercury lamp at 90 ° C., UV irradiation was performed for 1 minute to polymerize the discotic liquid crystalline molecules. Then, it stood to cool to room temperature, and produced the protective films 20 and 21 with an optically anisotropic layer.

[Protective film 22 with optically anisotropic layer]

  A cholesteric liquid crystal liquid prepared by mixing a nematic liquid crystal compound represented by the above formula and a chiral agent represented by the following formula so that the selective reflection wavelength is 290 to 310 nm and adding a photopolymerization initiator thereto. Coated on a biaxially stretched PET film, heat treated at 80 ° C. for 3 minutes, irradiated with ultraviolet rays and crosslinked to obtain a retardation layer B having a thickness of 1.9 μm, Re of 2 nm, and Rth of 132 nm, It is laminated with a commercially available cellulose acylate film (Fujitac TD80U (manufactured by Fuji Photo Film Co., Ltd.)) through an acrylic adhesive layer having a thickness of 15 μm, the biaxially stretched PET film is peeled off, and Re is 2 nm. A laminated retardation plate 22 having a thickness of 182 nm was obtained.

[Protective film 23 with optically anisotropic layer]
A polyimide synthesized from 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropane and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl is dissolved in cyclohexanone. A 15% by weight solution was prepared. This polyimide solution was applied on a TAC film having a thickness of 80 μm (TD80U manufactured by Fuji Photo Film Co., Ltd.) (base material) and dried at 120 ° C. for 10 minutes, and a non-liquid crystalline polymer layer having a thickness of 5 μm, A laminate with a TAC film was obtained. This laminate was stretched 1.05 times in the tenter abscissa to obtain a protective film 23 with an optically anisotropic layer, which is a laminate having a thickness of 73 μm. This laminate is a laminate of a stretched TAC film as an optical compensation layer and a stretched non-liquid crystalline polymer layer as an optical compensation layer.

[Preparation of protective film with antireflection function (films 24 and 25)]
[Protective film 24 with antireflection function]
(Preparation of coating solution for light scattering layer)
50 g of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (PETA, Nippon Kayaku Co., Ltd.) was diluted with 38.5 g of toluene. Further, 2 g of a polymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) was added and mixed and stirred. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.51.
Further, a 30% toluene dispersion of crosslinked polystyrene particles having an average particle size of 3.5 μm (refractive index: 1.60, SX-350, manufactured by Soken Chemical Co., Ltd.) dispersed in this solution for 20 minutes at 10,000 rpm with a Polytron disperser. Add 13.3 g of 30% toluene dispersion of 1.7 g and crosslinked acrylic-styrene particles having an average particle size of 3.5 μm (refractive index 1.55, manufactured by Soken Chemical Co., Ltd.), and finally, fluorine-based surface modification 0.75 g of agent (FP-1) and 10 g of silane coupling agent (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to obtain a finished solution.
The liquid mixture was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for the light scattering layer.

(Preparation of coating solution for low refractive index layer)
First, sol solution a was prepared as follows. A stirrer, a reactor equipped with a reflux condenser, 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane (KBM5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of diisopropoxyaluminum ethyl acetoacetate were added and mixed. After adding 30 parts of ion-exchanged water and reacting at 60 ° C. for 4 hours, it was cooled to room temperature to obtain a sol solution a. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.
Thermally crosslinkable fluorine-containing polymer having a refractive index of 1.42 (JN-7228, solid content concentration 6%, manufactured by JSR Corporation) 13 g, silica sol (silica, MEK-ST particle size difference, average particle size 45 nm, solid content 30% concentration, manufactured by Nissan Chemical Co., Ltd.) 1.3 g, the above sol a0.6 g, methyl ethyl ketone 5 g, and cyclohexanone 0.6 g were added. A layer coating solution was prepared.

(Preparation of transparent protective film with antireflection layer)
An 80 μm-thick triacetylcellulose film (Fujitac TD80U, manufactured by Fuji Photo Film Co., Ltd.) is unwound in a roll form, and the above functional layer (light scattering layer) coating solution has a line number of 180 lines / inch, depth Using a microgravure roll with a diameter of 50 mm and a doctor blade having a gravure pattern of 40 μm, coating was performed under the conditions of a gravure roll rotation speed of 30 rpm and a conveyance speed of 30 m / min, drying at 60 ° C. for 150 seconds, and further under nitrogen purge Using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.), the coating layer is cured by irradiating ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 250 mJ / cm ² , and a functional layer having a thickness of 6 μm And wound up.
The triacetyl cellulose film coated with the functional layer (light scattering layer) is unwound again, and the prepared coating liquid for the low refractive index layer is gravure with a line number of 180 lines / inch and a depth of 40 μm on the light scattering layer side. Using a micro gravure roll with a diameter of 50 mm and a doctor blade having a pattern, it is applied under the conditions of a gravure roll rotation speed of 30 rpm and a conveyance speed of 15 m / min, dried at 120 ° C. for 150 seconds, and further dried at 140 ° C. for 8 minutes. Then, using a 240 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) under a nitrogen purge, ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 900 mJ / cm ² were irradiated, and a low refraction of 100 nm thickness A rate layer was formed, wound up, and a protective film with antireflection function (film 24) was produced.

[Protective film 25 with antireflection function]
(Preparation of coating solution for hard coat layer)
750.0 parts by mass of trimethylolpropane triacrylate (TMPTA, Nippon Kayaku Co., Ltd.), 270.0 parts by mass of poly (glycidyl methacrylate) having a mass average molecular weight of 3000, 730.0 g of methyl ethyl ketone, 500.0 g of cyclohexanone and light A polymerization initiator (Irgacure 184, manufactured by Nippon Ciba-Geigy Co., Ltd.) 50.0 g was added and stirred. The solution was filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a coating solution for a hard coat layer.

(Preparation of titanium dioxide fine particle dispersion)
As the titanium dioxide fine particles, titanium dioxide fine particles (MPT-129, manufactured by Ishihara Sangyo Co., Ltd.) containing cobalt and surface-treated with aluminum hydroxide and zirconium hydroxide were used.
The following dispersant (38.6 g) and cyclohexanone (704.3 g) were added to 257.1 g of the particles and dispersed by dynomill to prepare a titanium dioxide dispersion having a mass average diameter of 70 nm.

(Preparation of coating solution for medium refractive index layer)
To 88.9 g of the above titanium dioxide dispersion, 58.4 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA), 3.1 g of a photopolymerization initiator (Irgacure 907), a photosensitizer (Kayacure DETX) 1.1 g of Nippon Kayaku Co., Ltd.), 482.4 g of methyl ethyl ketone and 1869.8 g of cyclohexanone were added and stirred. After sufficiently stirring, the solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution for a medium refractive index layer.

(Preparation of coating solution for high refractive index layer)
To 56.8 g of the above titanium dioxide dispersion, 47.9 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), photopolymerization initiator (Irgacure 907, Nippon Ciba Geigy ( Co., Ltd.) 4.0 g, photosensitizer (Kayacure-DETX, Nippon Kayaku Co., Ltd.) 1.3 g, methyl ethyl ketone 455.8 g, and cyclohexanone 1427.8 g were added and stirred. The solution was filtered through a polypropylene filter having a pore diameter of 0.4 μm to prepare a coating solution for a high refractive index layer.

(Preparation of coating solution for low refractive index layer)
The following copolymer (P-1) is dissolved in methyl isobutyl ketone to a concentration of 7% by mass, and a terminal methacrylate group-containing silicone resin X-22-164C (manufactured by Shin-Etsu Chemical Co., Ltd.) is added to the solid content. 3% of the photoradical generator Irgacure 907 (trade name) was added in an amount of 5% by mass based on the solid content to prepare a coating solution for a low refractive index layer.

Copolymer (P-1)

(Production of transparent protective film with antireflection layer)
A hard coat layer coating solution was applied onto a triacetyl cellulose film (Fujitac TD80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm using a gravure coater. After drying at 100 ° C., an irradiance of 400 mW / cm using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. ^{2. The} coating layer was cured by irradiating ultraviolet rays with an irradiation amount of 300 mJ / cm ² to form a hard coat layer having a thickness of 8 μm.
On the hard coat layer, a medium refractive index layer coating solution, a high refractive index layer coating solution, and a low refractive index layer coating solution were successively applied using a gravure coater having three coating stations.

The medium refractive index layer is dried at 100 ° C. for 2 minutes, and the ultraviolet curing condition is 180 W / cm ² air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the oxygen concentration becomes 1.0 vol% or less. The irradiance was 400 mW / cm ² and the irradiation amount was 400 mJ / cm ² . The medium refractive index layer after curing had a refractive index of 1.630 and a film thickness of 67 nm.

The drying conditions of the high refractive index layer and the low refractive index layer are both 90 ° C., 1 minute, 100 ° C., 1 minute, and the ultraviolet curing condition is nitrogen so that the oxygen concentration is 1.0 volume% or less. While purging, a 240 W / cm ² air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) was used to obtain an irradiation amount of 600 mW / cm ² and an irradiation amount of 600 mJ / cm ² .
The cured high refractive index layer had a refractive index of 1.905 and a film thickness of 107 nm, and the low refractive index layer had a refractive index of 1.440 and a film thickness of 85 nm. In this way, a transparent protective film (film 25) with an antireflection layer was produced.

[Example 1]
(Preparation of polarizing plate 1)
Infrared heaters (manufactured by NGK Co., Ltd.) were connected in the width direction of a polyvinyl alcohol (PVA) film having a thickness of 75 μm and a polymerization degree of 2400 so as to be controlled at intervals of 70 mm. A temperature gradient was applied in the width direction so that the central portion was 30 ° C. and the end portion was 40 ° C., and after heat treatment for about 5 seconds, it was swollen with warm water at 30 ° C. for 40 seconds, and then the iodine concentration was 0.06 mass. %, And immersed in an aqueous solution of 6% by mass of potassium iodide at 30 ° C. for 60 seconds, and then immersed in an aqueous solution of boric acid concentration of 4% by mass and 3% by mass of potassium iodide at 40 ° C. for 60 seconds. In the meantime, it was stretched so that the longitudinal direction was 5.2 times the original length. At this time, the stretching is performed by sequential biaxial stretching using a tenter clip, and as described above, the film is stretched 5.2 times in the longitudinal direction and then 1.1 times in the transverse direction, and finally the longitudinal direction is the original. It extended | stretched so that it might become 5 times the length.
Then, it was made to dry for 4 minutes at 50 degreeC, and the polarizer 1 was obtained. The maximum film thickness in the width direction of the polarizer 1 was 32.0 μm, the minimum film thickness was 30.0 μm, and the difference between the maximum film thickness and the minimum film thickness was 2.0 μm.

The already prepared cellulose acylate film 1 and TD80U manufactured by Fuji Photo Film Co., Ltd. were immersed in an aqueous sodium hydroxide solution at 55 ° C. at 1.5 mol / liter, and then the sodium hydroxide was thoroughly washed away with water. . Then, after being immersed in a diluted sulfuric acid aqueous solution at 0.005 mol / liter at 35 ° C. for 1 minute, it was immersed in water to sufficiently wash away the diluted sulfuric acid aqueous solution. Finally, the sample was thoroughly dried at 120 ° C.
The cellulose acylate film 1 saponified as described above and TD80U manufactured by Fuji Photo Film Co., Ltd. were bonded using a polyvinyl alcohol adhesive so as to sandwich the polarizer, and further heated at 70 ° C. for 30 minutes. did. Thereafter, the edge of the sheet was cut with a cutter 3 cm from the width direction to produce a roll-shaped polarizing plate 1 having an effective width of 1200 mm and a length of 50 m.
Table 3 shows the polarization performance (single plate transmittance, polarization degree) of the polarizer maximum film thickness portion in the width direction of the obtained polarizing plate 1 and the polarization performance (single plate transmittance, polarization degree) of the minimum film thickness portion. It was.

(Preparation of polarizing plates 2 to 23 and 27 to 30)
In addition, polarizing plates 2 to 23 and 27 to 30 were prepared in the same manner as in the case of the polarizing plate 1 using the protective films 2 to 25 and the commercially available cellulose acylate film that were already prepared, in the combination of Table 3. . Table 2 shows the thickness and degree of polymerization of the PVA film on which each polarizing plate was produced, the manufacturing conditions of the polarizer, and the like.
Tables 2 and 3 show the maximum film thickness and the minimum film thickness in the width direction of the obtained polarizer, the polarization performance of the maximum film thickness portion of the obtained polarizing plate, and the polarization performance of the minimum film thickness portion.
Here, as a commercially available cellulose acylate film, Fujitac TF80U, Fujitac TD80U (manufactured by Fuji Photo Film Co., Ltd.), and KC80UVSFD (manufactured by Konica Capto Co., Ltd.) were used.
At this time, since the polarizer and the protective films on both sides of the polarizer are manufactured in a roll form, the longitudinal directions of the roll films are parallel to each other and are continuously bonded. Moreover, in the protective film arrange | positioned at the cell side, the transmission axis of a polarizer and the slow axis of each cellulose acylate film 1-19 are parallel.
In the case of the protective films 20 to 23 with an optically anisotropic layer, the transparent support side was attached to one side of the polarizer using a polyvinyl alcohol-based adhesive. The slow axis of the transparent support and the transmission axis of the polarizer were arranged in parallel.

(Preparation of polarizing plate 31)
Similarly, a polarizing plate having a total width of 1200 mm, in which both sides of the polarizer (see Table 3 polarizing plate No. 31) are commercially available cellulose acylate films (TD80U manufactured by Fuji Photo Film Co., Ltd.) was produced. A stretched film having a thickness of 90 μm was adhered to one side of the acrylic adhesive layer having a thickness of 25 μm to obtain a polarizing plate 31. The stretched film was obtained by transversely stretching a norbornene-based resin film (manufactured by JSR Co., Ltd., ARTON) having a thickness of 100 μm through a tenter, and has Re95 nm and Rth 50 nm. Re and Rth were calculated from refractive indexes measured with KOBRA 21ADH manufactured by Oji Scientific Instruments.
An acrylic adhesive material was attached to the cell-side surface of the polarizing plate 31 produced above, and a separate film was attached to the adhesive material. A protective film was attached to the surface opposite to the cell.

[Comparative Example 1] (Preparation of polarizing plates 24 to 26)
Polarizing plates 24 to 26 were produced in the same manner as in Example 1 except that the infrared heater was not connected and the stretching was not biaxial stretching but free uniaxial stretching. The combinations of protective films are as shown in Table 3.

[Reflectance measurement]
Using a spectrophotometer (manufactured by JASCO Corporation), the spectral reflectance at an incident angle of 5 ° is measured from the functional film side in the wavelength region of 380 to 780 nm, and the integrating sphere average reflectance of 450 to 650 nm is obtained. As a result, it was 2.3% for the polarizing plates 4 and 12 using the film 26 which is a transparent protective film with an antireflection layer, and 0 for the polarizing plates 7 and 13 using a film 27 which was a transparent protective film with an antireflection layer. 4%. Here, the protective film on the transparent protective film with the antireflection layer was peeled off, and the reflectance was measured.

[Implementation to panel]
[Example 2]
(Mounting on VA panel)
The front and back polarizing plates and the retardation plate of the VA mode liquid crystal TV (LC-30AD1, manufactured by Sharp Corporation) were peeled off, and the front and back sides of the polarizing plates 1 to 23 and 27 to 31 prepared in Example 1 were used. 4 and a commercially available polarizing plate without a viewing angle compensator (HLC2-5618, manufactured by Sanlitz Co., Ltd.) with the panel size (30 inches, 65 cm × 39 cm) and the combinations shown in Table 4 Pasted.
In this case, the absorption axis of the polarizing plate on the viewing side is in the horizontal direction of the panel, the absorption axis of the polarizing plate on the backlight side is in the vertical direction of the panel, and the adhesive material surface is on the liquid crystal cell side.
After removing the protective film, using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM), the viewing angle (contrast ratio is 10 or more and black side) in 8 steps from black display (L1) to white display (L8) Range without gradation inversion). When any polarizing plate was used, good viewing angle characteristics were obtained.

(Evaluation of screen uniformity)
About the liquid crystal panel using the polarizing plate produced in Example 1 produced above, screen uniformity was evaluated.
Using a liquid crystal panel with a polarizing plate attached, a liquid crystal TV was assembled and the backlight was turned on. For the evaluation, a 30-inch liquid crystal panel was used.
The screen uniformity was evaluated as follows. The results are shown in Table 4.
A: Every part of the screen has uniform brightness, and the uniformity is very good.
○: On the screen, if you look closely, you can see a place that looks slightly dark.
×: There is a dark part on the screen.
XX: A clearly dark part is recognized on the screen.

[Comparative Example 2]
About the polarizing plates 24-26 produced in the comparative example 1, it mounted in the VA panel similarly to Example 2. FIG.
After removing the protective film, using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM), the viewing angle (contrast ratio is 10 or more and black side) in 8 steps from black display (L1) to white display (L8) However, the viewing angle characteristics were poor when using any of the polarizing plates, which was inferior to when using the polarizing plate of the present invention.
In addition, the uniformity of the screen was evaluated in the same manner, but there was a dark portion on the screen, which was inferior to the polarizing plate of the present invention. (Table 4)

[Example 3]
(Preparation of bend alignment liquid crystal cell)
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The obtained two glass substrates were faced to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 5.7 μm. A liquid crystal compound having a Δn of 0.1396 (ZLI1132, manufactured by Merck & Co., Inc.) was injected into the cell gap to prepare a bend alignment liquid crystal cell (30 inches, 65 cm × 39 cm).

(Production of liquid crystal display device)
The produced polarizing plates 27 and 28 were attached so as to sandwich the produced bend alignment cell. (Combination is described in Table 5) The optically anisotropic layer of the polarizing plate faces the cell substrate, and the rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer facing the liquid crystal cell are arranged to be antiparallel. .
When the liquid crystal display device thus produced was turned on and observed, it was found that the liquid crystal display device using the polarizing plate of the present invention is preferable because the change in contrast viewing angle and color viewing angle is small.

(Evaluation of screen uniformity)
In addition, the above-described liquid crystal panel was evaluated for screen uniformity. Evaluation was performed as follows. The results are shown in Table 5.
A: Every part of the screen has uniform brightness, and the uniformity is very good.
○: On the screen, if you look closely, you can see a place that looks slightly dark.
×: There is a dark part on the screen.
XX: A clearly dark part is recognized on the screen.

[Comparative Example 3]
About the polarizing plates 24-26 produced in the comparative example 1, it mounted in the panel similarly to Example 3. FIG.
After removing the protective film, using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM), the viewing angle (contrast ratio is 10 or more and black side) in 8 steps from black display (L1) to white display (L8) The range without gradation inversion) was measured, but when any polarizing plate was used, the viewing angle characteristics were poor, which was inferior to the case where the polarizing plate of the present invention was used.
In addition, the uniformity of the screen was evaluated in the same manner, but there was a dark portion on the screen, which was inferior to the polarizing plate of the present invention. (Table 5)

It is a figure which shows typically the cross-sectional structure of an example of the polarizing plate of this invention. It is a figure which shows typically the cross-sectional structure of an example of the liquid crystal display device of this invention.

Explanation of symbols

1, 11, 21 Polarizer 2, 12.22 TAC1, TAC1-1, TAC1-2: One side protective film (disposed on the liquid crystal cell side)
3, 13, 23 TAC2, TAC2-1, TAC2-2 :: Protective film 4 on the opposite side Functional film 5 Polarizing plate 30 VA mode cell

Claims (17)

  A roll-shaped polarizing plate in which a protective film is bonded to at least one side of a polarizer made of polyvinyl alcohol having a polymerization degree of 1000 to 3800, and the difference between the maximum film thickness and the minimum film thickness in the width direction of the polarizer is 0 to A roll-shaped polarizing plate having a thickness of 3 μm.   The roll-shaped polarizing plate according to claim 1, wherein a film thickness difference between 1 cm in the width direction of the polarizer is 0.25 μm / cm or less.   The roll-shaped polarizing plate according to claim 1 or 2, wherein the total width is 400 mm to 3000 mm. The front-side retardation value Re _{(590) at a} wavelength of 590 nm and the retardation value Rth ₍₅₉₀₎ in the film thickness direction at a wavelength of 590 nm of the protective film on one side are represented by the following formula (I):
The roll-shaped polarizing plate according to any one of claims 1 to 3, wherein (II) and (II) are satisfied.
Formula (I): 20 nm ≦ Re ₍₅₉₀₎ ≦ 200 nm
Formula (II): 70 nm ≦ Rth ₍₅₉₀₎ ≦ 400 nm The ratio of the Re ₍₅₉₀₎ value to the Rth ₍₅₉₀₎ value (Re / Rth ratio) of the protective film on one side is 0.1 to 0.8. 4. The roll-shaped polarizing plate according to any one of 4 above. The one-side protective film is a cellulose acylate film comprising, as a main polymer component, cellulose acylate which is a mixed fatty acid ester of cellulose in which a hydroxyl group of cellulose is substituted with an acetyl group and an acyl group having 3 or more carbon atoms. ,
6. The cellulose acylate according to claim 1, wherein the substitution degree A of the acetyl group and the substitution degree B of the acyl group having 3 or more carbon atoms satisfy the following formulas (III) and (IV): The roll-shaped polarizing plate in any one of.
Formula (III): 2.0 ≦ A + B ≦ 3.0
Formula (IV): 0 <B   The roll-shaped polarizing plate according to claim 6, wherein the acyl group having 3 or more carbon atoms is a butanoyl group.   The roll polarizing plate according to claim 6, wherein the acyl group having 3 or more carbon atoms is a propionyl group. The protective film on one side is a film made of cellulose acylate obtained by substituting the hydroxyl group of the glucose unit constituting cellulose with an acyl group having 2 or more carbon atoms, and 2 of glucose units constituting cellulose When the substitution degree of the hydroxyl group at the position with DS2 is DS2, the substitution degree with the acyl group of the hydroxyl group at position 3 is DS3, and the substitution degree with the acyl group of the hydroxyl group at position 6 is DS6, the following formulas (V) and (VI The roll-like polarizing plate according to claim 1, wherein the film is a cellulose acylate film satisfying
Formula (V): 2.0 ≦ DS2 + DS3 + DS6 ≦ 3.0
Formula (VI): DS6 / (DS2 + DS3 + DS6) ≧ 0.315   The roll polarizing plate according to claim 9, wherein the acyl group is an acetyl group.   The roll according to any one of claims 1 to 10, wherein the protective film on one side contains at least one of a plasticizer, an ultraviolet absorber, a release accelerator, a dye, and a matting agent. -Shaped polarizing plate.   The roll-shaped polarizing plate according to any one of claims 1 to 11, wherein the protective film on one side contains one or more retardation enhancers of a rod-shaped compound or a disk-shaped compound.   The roll-shaped polarizing plate according to any one of claims 1 to 11, wherein the protective film on one side is provided with an optically anisotropic layer on a polymer film.   The at least one layer of a hard-coat layer, a glare-proof layer, and an antireflection layer was provided in the surface of the protective film arrange | positioned on the opposite side to the said one-side protective film, The Claim 1 thru | or 13 characterized by the above-mentioned. Roll polarizing plate.   The roll-like polarizing plate according to claim 1, wherein a retardation film is bonded to the one protective film side using an adhesive.   A polarizing plate cut out from the roll-shaped polarizing plate according to claim 1.   17. A liquid crystal display device, wherein the polarizing plate according to claim 16 is used so that the protective film on one side is disposed on the liquid crystal cell side.

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