JP2007101678A - Polarizing plate and liquid crystal display apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate improved in light leakage in a circumferential part of a screen due to changes in temperature and humidity or continuous lighting of a liquid crystal display apparatus while keeping high optical performance and adhesiveness, and to provide a liquid crystal display apparatus using the polarizing plate. <P>SOLUTION: The polarization plate has protective films on both sides of a polarizer, wherein one of the protective films is a retardation plate having two optical anisotropic layers, and one of the optical anisotropic layers contains at least one kind of a liquid crystalline compound. At least one surface of the above polarization plate is coated with a pressure-sensitive adhesive layer that is formed of a composition of a (meth)acrylic copolymer comprising a specified (meth)acrylic copolymer (A) having a functional group reactive with a polyfunctional compound (B) and a polyfunctional compound (B), and that has a specified gel fraction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is used for a reflective liquid crystal display device, a transflective liquid crystal display device, a transmissive liquid crystal display device, a GH-LCD, a PS conversion element, an optical disk writing pickup, a brightness enhancement film, or an antireflection film. A polarizing plate including a retardation plate effective as a / 4 plate as a protective film, and having high adhesiveness, light caused by contraction stress of the polarizing plate at the periphery of the screen during continuous lighting of a liquid crystal display device while having high adhesiveness The present invention relates to a polarizing plate with improved leakage and a liquid crystal display device using the same.

  The λ / 4 plate has a great many applications, and is already used for a reflective LCD, a transflective LCD, a brightness enhancement film, a pickup for an optical disk, and a PS conversion element. Most of the λ / 4 plates currently used for them are retardation plates that exhibit optical anisotropy by stretching a polymer film. The optical orientation of the polymer film generally corresponds to the longitudinal or lateral direction of the sheet or roll film, and a polymer film having an optical axis or slow axis in the oblique direction of the sheet or roll is manufactured. It is very difficult. In many cases where a retardation plate is used, it is disposed at an angle that is neither parallel nor orthogonal to the transmission axis of the polarizing plate. In many cases, two or more retardation plates and polarizing plates are arranged at angles that are neither parallel nor orthogonal. In general, since the transmission axis of the polarizing plate is perpendicular to the roll film, in order to attach the retardation plate and the polarizing plate, cut each film at a predetermined angle and attach the resulting chip. It is necessary to match. When a laminated body of a retardation plate and a polarizing plate is manufactured by chip bonding, an adhesive application step, a chip cut or a chip bonding step is required, and the bonding process may be a problem. If this bonding is not accurate, the quality is likely to deteriorate due to axial misalignment, the yield decreases, the cost increases, and deterioration due to contamination tends to occur.

  In the polymer film, the expression of refractive index anisotropy in the three-dimensional direction is affected by various conditions such as the draw ratio, temperature, draw speed, and polymer molecular weight. Therefore, it is difficult to precisely control the optical anisotropy of the polymer film.

  In order to solve such a problem, a coating liquid containing a discotic liquid crystalline compound or a rod-like liquid crystalline compound is applied to a cellulose acylate film used as a protective film of a polarizing plate, and is oriented in a predetermined direction. A retardation plate having a slow axis at an angle that is not parallel or orthogonal to the roll film has been proposed (Patent Documents 1 and 2). There is also disclosed a retardation plate whose orientation is fixed so that the disc surface of the discotic liquid crystalline compound is substantially perpendicular to the film surface (Patent Documents 3 to 6). Instead of sticking to the polarizing plate separately, it can be directly used for the protective film of the polarizing plate, thereby reducing the manufacturing process and thinning of the liquid crystal display panel.

  The method disclosed in the above-mentioned document is effective in that an inexpensive and thin liquid crystal display device can be obtained. However, in recent years, liquid crystal display devices are rapidly increasing in size and brightness, and light leakage at the periphery of the screen during black display due to contraction stress of the polarizing plate has become a problem. Although the polarizing plate tends to shrink due to changes in environmental temperature and humidity, it is fixed to the liquid crystal cell by the adhesive layer, so it is locally attached to the protective film of the polarizing plate, the adhesive layer, and the glass substrate of the liquid crystal cell (particularly the periphery of the screen). ), And light leakage occurs due to the change in birefringence due to the respective photoelasticity.

  When the liquid crystal cell to which the polarizing plate was attached was processed at high temperature, the water in the polarizing plate was released, so that the polarizing plate contracted greatly, and was taken out from the high temperature processing and from the high temperature processing to normal temperature and humidity. Immediately after that, light leakage occurs strongly. Thereafter, when the polarizing plate is left under normal temperature and humidity, the polarizing plate absorbs moisture and the contraction force of the polarizing plate decreases, so that light leakage also becomes weak. Even under normal temperature and humidity, when the backlight is continuously turned on, the temperature of the polarizing plate rises, and light leakage similar to that in the high temperature treatment occurs.

When a liquid crystal cell with a polarizing plate attached is processed under high temperature and high humidity, the polarizing plate absorbs moisture and is left at room temperature and humidity to release moisture in the polarizing plate. The shrinkage force increases. As this contraction force increases, light leakage increases.
Therefore, there is a demand for improvement in light leakage at the periphery of the screen due to such changes in temperature and humidity and continuous lighting.

  In the TN mode, the light leakage as described above has been improved by softening the adhesive that bonds the polarizing plate to the liquid crystal cell and relaxing the shrinkage stress applied to the optical compensation film. Patent Documents 7 to 9 disclose that the shrinkage stress is alleviated by increasing the creep value of the adhesive.

  In addition, it has been disclosed to reduce various elastic moduli of an adhesive that bonds a polarizing plate or an optical compensation film to a liquid crystal cell in order to reduce shrinkage stress. For example, the relaxation elastic modulus (Patent Document 10), the elastic modulus (Patent Documents 11 to 14), and the shear elastic modulus (Patent Document 15) can be mentioned.

  In order to obtain an adhesive that relieves the shrinkage stress as described above, it is effective to reduce the gel fraction of the adhesive that bonds the polarizing plate or the optical compensation film to the liquid crystal cell as disclosed in Patent Document 16. It is believed that.

Conventionally, the pressure-sensitive adhesive is softened in order to relieve the stress as described above, and the adhesive strength of the pressure-sensitive adhesive is weakened in order to impart reworkability to the polarizing plate as disclosed in Patent Documents 17-19. I was designing.
JP 2001-4837 A JP 2004-53841 A Japanese Patent Laid-Open No. 9-292522 JP 2000-56310 A JP 2000-104073 A JP 2000-105316 A JP 2001-272541 A JP 2003-50313 A JP 2001-350020 A JP-A-11-52133 JP 2001-272542 A JP 2000-321992 A JP 2000-162584 A JP 2000-155215 A JP 2001-272544 A JP 2000-155213 A JP-A-11-258419 JP 2000-9973 A JP 2004-78171 A

  An object of the present invention is to provide a polarizing plate that has improved optical leakage and light leakage at the periphery of the screen due to changes in temperature and humidity and continuous lighting of the liquid crystal display device while having high optical performance and adhesiveness, and a liquid crystal display device using the polarizing plate Is to provide. Further, a polarizing plate including a retardation plate effective as a λ / 4 plate as a protective film, which has a high optical compensation function and improves light leakage at the periphery of the screen due to temperature and humidity changes and continuous lighting of the liquid crystal display device, and It is to provide a liquid crystal display device using the polarizing plate.

  As a result of intensive studies, the present inventor has identified the stress applied to the protective film and the adhesive layer of the polarizing plate due to the contraction of the polarizing plate as a specific adhesive layer provided on the side where the polarizing plate is attached to the glass plate of the liquid crystal cell. It was found that the composition can be suppressed and light leakage at the periphery of the screen due to temperature and humidity changes and continuous lighting can be improved while having high adhesiveness. In the liquid crystal display device in which the absorption axes of the polarizing plates on the front and back sides of the liquid crystal cell are orthogonal to each other and the absorption axis is parallel to the long side or the short side of the liquid crystal cell, Unlike a liquid crystal display device that is orthogonal and has an absorption axis of 45 degrees with the long or short side of the liquid crystal cell, light leakage at the periphery of the screen due to the contraction stress of the polarizer causes the polarizing plate to It was found that it can be improved by hardening the pressure-sensitive adhesive layer attached to the glass plate. Furthermore, it is determined that the temperature of the backlight surface of the liquid crystal display device is related to the light leakage at the periphery of the screen when the liquid crystal display device is continuously lit. It was found that light leakage at the periphery of the screen during lighting can be improved.

That is, this invention is a polarizing plate and a liquid crystal display device of the following structure, and the said objective of this invention is achieved by this.
(1) A polarizing plate having protective films on both sides of a polarizing film, wherein one of the protective films is a retardation plate having at least two optically anisotropic layers, and at least of the optically anisotropic layers One layer contains at least one liquid crystalline compound and has an adhesive layer on at least one side of the polarizing plate, and when the adhesive layer is (A) (a ₁ ) a homopolymer, the Tg is less than −30 ° C. (meth) acrylic acid ester monomers, (a ₂₎ a compound having a Tg of -30 ° C. or more vinyl groups when polymerized into a homopolymer, and the reactivity to (a ₃₎ a polyfunctional compound (B) A (meth) acrylic copolymer comprising a functional group-containing monomer having a vinyl group with (meth) acrylic acid ester (a ₁ ) being 75 parts by mass or more in terms of mass ratio of monomer units (a ₂₎ is not more than 25 parts by weight, and Functional group-containing monomer (a ₃₎ is, the monomer (a ₁₎ and the compound copolymer 100 parts by weight is 10 parts by mass or less with respect to the sum 100 parts by weight of (a _2), and (B) a functional group-containing (Meth) acrylic comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups in the molecule that can react with the functional group of the monomer (a ₃ ) to form a crosslinked structure A polarizing plate, which is formed by coating a pressure-sensitive adhesive containing a composition of a copolymer, and further has a gel fraction of 40% by mass or more and 90% by mass or less.
(2) A polarizing plate having protective films on both sides of the polarizing film, wherein one of the protective films is a retardation plate having at least two optically anisotropic layers, and at least of the optically anisotropic layers One layer contains at least one liquid crystalline compound and has an adhesive layer on at least one side of the polarizing plate, and the Tg when the adhesive layer is a (A ₁ ) (a ₁₁ ) homopolymer is less than −30 ° C. (Meth) acrylic acid ester monomer, (a ₁₂ ) a compound having a vinyl group having a Tg of −30 ° C. or higher when (h) is a homopolymer, and (a ₁₃ ) reactive to the polyfunctional compound (B) A (meth) acrylic copolymer comprising a functional group-containing monomer having a vinyl group, wherein (meth) acrylic acid ester (a ₁₁ ) is 75 parts by mass or more in terms of mass ratio of monomer units ( a ₁₂₎ is not more than 25 parts by weight And functional group-containing monomer (a ₁₃₎ is, the monomer (a ₁₁₎ and the compound 10 parts by mass or less with respect to the sum 100 parts by weight of (a _12), copolymer 100 weight average molecular weight is 1,000,000 or more Parts by mass,
(A ₂ ) (a ₂₁ ) a (meth) acrylic acid ester monomer having a Tg of less than −30 ° C. when it is a homopolymer, and a vinyl group having a Tg of −30 ° C. or more when it is a homopolymer (a ₂₂ ) (Meth) acrylic copolymer comprising a compound and (a ₂₃ ) a functional group-containing monomer having reactivity with respect to the polyfunctional compound (B), wherein (meth) The acrylic ester (a ₂₁ ) is 75 parts by mass or more, the vinyl group-containing compound (a ₂₂ ) is 25 parts by mass or less, and the functional group-containing monomer (a ₂₃ ) comprises the monomer (a ₂₁ ) and 20 to 200 parts by mass of a copolymer having a mass average molecular weight of not more than 10 parts by mass and not more than 100,000 with respect to 100 parts by mass of the sum of the compounds (a ₂₂ ), and (B) a functional group-containing monomer (a ₁₃ ) and Reacts with the functional group of (a ₂₃ ) A pressure-sensitive adhesive containing a composition of a (meth) acrylic copolymer comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups capable of forming a bridge structure in the molecule. The adhesive has a gel fraction of 40% by mass or more and 90% by mass or less, and the functional group in the (meth) acrylic copolymers (A ₁ ) and (A ₂ ). A polarizing plate characterized in that the introduction amount of repeating units derived from the contained monomers (a ₁₃ ) and (a ₂₃ ) satisfies a functional group distribution rate of 0 to 15% by mass defined by the following formula (1) .
Formula (1): Functional group partition ratio = [mass of repeating unit derived from functional group-containing monomer (a ₂₃ ) in [(meth) acrylic copolymer (A ₂ ) / (meth) acrylic copolymer] The mass of the repeating unit derived from the functional group-containing monomer (a ₁₃ ) in (A ₁ )] × 100.
(3) The 1 or 2 above, wherein the glass transition temperature of the (meth) acrylic copolymer (A), (A ₁ ), or (A ₂ ) in the adhesive layer is 0 ° C. or lower. The polarizing plate as described in.
(4) The protective film on the side opposite to the side having at least two optically anisotropic layers of the polarizing film is a retardation plate having an optically anisotropic layer. (3) The polarizing plate in any one.
(5) The protective film on the side opposite to the side having at least two optically anisotropic layers of the polarizing film is a retardation plate comprising an optically anisotropic layer containing at least one liquid crystalline compound. The polarizing plate as described in any one of (1) to (3) above.
(6) The adhesive layer is bonded to an alkali-free glass plate with an area of 10 mm in width and 10 mm in length, and the creep amount after applying a load of 200 g for 1 hour in an atmosphere at 25 ° C. is less than 40 μm. The polarizing plate according to any one of (1) to (5) above.
(7) The 90 ° peeling adhesive force in an atmosphere of 25 ° C. with respect to the alkali-free glass plate of the adhesive layer is 10 N / 25 mm width or more, wherein the adhesive layer is any one of the above (1) to (6) Polarizer.

(8) The 90 ° peel adhesion after treatment for 5 hours in an atmosphere of 70 ° C. with respect to the alkali-free glass plate of the adhesive layer is 10 N / 25 mm width or more at any measurement temperature of 0 to 90 ° C. The polarizing plate according to any one of the above (1) to (7), which is characterized.
(9) The polarizing plate according to any one of (1) to (8) above, wherein the adhesive layer has an elastic modulus at 25 ° C. of 0.08 MPa or more.
(10) The polarizing plate according to any one of (1) to (9), wherein the adhesive layer has an elastic modulus at 90 ° C. of 0.06 MPa or more.
(11) The polarizing plate according to any one of (1) to (10) above, wherein the adhesive layer has a shear elastic modulus of 0.1 GPa to 100 GPa.
(12) The polarizing plate as described in any one of (1) to (11) above, wherein the pressure-sensitive adhesive has a gel fraction of 60% by mass or more and 90% by mass or less.
(13) The polarizing plate according to any one of (1) to (12), wherein the adhesive layer has a thickness of 5 to 30 μm.
(14) The polarizing plate according to any one of (1) to (13), wherein Nz is smaller than 0 when Nz of the retardation plate is defined as in the following formula (2): .
Formula (2): Nz = 0.5 + Rth / Re
Here, Re and Rth represent an in-plane retardation value of the retardation plate and a retardation value in the thickness direction, respectively.
(15) The optically anisotropic layer includes a first optically anisotropic layer containing a discotic liquid crystalline compound and a second optically anisotropic layer containing a rod-like liquid crystalline compound, and the disco The alignment state is fixed so that the disc surface of the tick liquid crystalline compound is substantially perpendicular to the first optically anisotropic layer surface, and the major axis direction of the rod-like liquid crystalline compound is the second axis direction. The polarizing plate according to any one of the above (1) to (14), wherein the alignment state is fixed so as to be substantially perpendicular to the surface of the optically anisotropic layer.

(16) A polarizing plate having a protective film on both sides of a polarizing film, the retardation film having an optically anisotropic layer containing at least one liquid crystalline compound on one side of the protective film, The isotropic layer contains a discotic liquid crystalline compound, and the alignment state is fixed so that the disc surface of the discotic liquid crystalline compound is substantially perpendicular to the optically anisotropic layer surface, A (meth) acrylic acid ester monomer having an adhesive layer on at least one side of the polarizing plate, and having a Tg of less than −30 ° C. when the adhesive layer is (A) (a ₁ ) homopolymer, (a ₂ ) homopolymer A (meth) acrylic copolymer comprising a compound having a vinyl group with a Tg of −30 ° C. or higher and a functional group-containing monomer having reactivity to the polyfunctional compound (B) (a ₃ ) A polymer comprising monomer units In quantitative ratios (meth) acrylic acid ester (a ₁₎ 75 parts by mass or more, there is a compound having a vinyl group (a ₂₎ is 25 parts by mass or less, and the functional group-containing monomer (a ₃₎ is, the It reacts with the functional group of 100 parts by mass of the copolymer that is 10 parts by mass or less with respect to 100 parts by mass of the sum of the monomer (a ₁ ) and the compound (a ₂ ), and the functional group of the (B) functional group-containing monomer (a ₃ ). And a pressure-sensitive adhesive containing a (meth) acrylic copolymer composition comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups capable of forming a crosslinked structure in the molecule. A polarizing plate, wherein an adhesive is coated and formed, and the gel fraction of the pressure-sensitive adhesive is 40% by mass or more and 90% by mass or less.
(17) A polarizing plate having a protective film on both sides of a polarizing film, the retardation film having an optically anisotropic layer containing at least one liquid crystalline compound on one side of the protective film, The isotropic layer contains a discotic liquid crystalline compound, and the alignment state is fixed so that the disc surface of the discotic liquid crystalline compound is substantially perpendicular to the optically anisotropic layer surface, A (meth) acrylic acid ester monomer having an adhesive layer on at least one surface of the polarizing plate and having a Tg of less than −30 ° C. when the adhesive layer is (A ₁ ) (a ₁₁ ) homopolymer, (a ₁₂ ) homo A (meth) acrylic compound comprising a compound having a vinyl group with a Tg of −30 ° C. or higher when used as a polymer, and (a ₁₃ ) a functional group-containing monomer having reactivity with the polyfunctional compound (B) A copolymer comprising monomer In in a weight ratio of (meth) acrylic acid ester (a ₁₁₎ is 75 parts by mass or more, a compound having a vinyl group A is (a ₁₂₎ is less than 25 parts by weight, and functional group-containing monomer (a ₁₃₎ is, 10 parts by mass or less and 100 parts by mass of a copolymer having a mass average molecular weight of 1 million or more with respect to 100 parts by mass of the monomer (a ₁₁ ) and the compound (a ₁₂ )
(A ₂ ) (a ₂₁ ) a (meth) acrylic acid ester monomer having a Tg of less than −30 ° C. when it is a homopolymer, and a vinyl group having a Tg of −30 ° C. or more when it is a homopolymer (a ₂₂ ) (Meth) acrylic copolymer comprising a compound and (a ₂₃ ) a functional group-containing monomer having reactivity with respect to the polyfunctional compound (B), wherein (meth) The acrylic ester (a ₂₁ ) is 75 parts by mass or more, the vinyl group-containing compound (a ₂₂ ) is 25 parts by mass or less, and the functional group-containing monomer (a ₂₃ ) comprises the monomer (a ₂₁ ) and 20 to 200 parts by mass of a copolymer having a mass average molecular weight of not more than 10 parts by mass and not more than 100,000 with respect to 100 parts by mass of the sum of the compounds (a ₂₂ ), and (B) a functional group-containing monomer (a ₁₃ ) and Reacts with the functional group of (a ₂₃ ) A pressure-sensitive adhesive containing a composition of a (meth) acrylic copolymer comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups capable of forming a bridge structure in the molecule. The adhesive has a gel fraction of 40% by mass or more and 90% by mass or less, and the functional group in the (meth) acrylic copolymers (A ₁ ) and (A ₂ ). A polarizing plate characterized in that the introduction amount of repeating units derived from the contained monomers (a ₁₃ ) and (a ₂₃ ) satisfies a functional group distribution rate of 0 to 15% by mass defined by the following formula (1) .
Formula (1): Functional group partition ratio = [mass of repeating unit derived from functional group-containing monomer (a ₂₃ ) in [(meth) acrylic copolymer (A ₂ ) / (meth) acrylic copolymer] The mass of the repeating unit derived from the functional group-containing monomer (a ₁₃ ) in (A ₁ )] × 100.
(18) The glass transition temperature of the (meth) acrylic copolymer (A), (A ₁ ), or (A ₂ ) in the pressure-sensitive adhesive layer is 0 ° C. or lower (16) Or the polarizing plate as described in (17).
(19) A liquid crystal display device comprising the polarizing plate according to any one of (1) to (18) above and a liquid crystal cell.

  The polarizing plate and the liquid crystal display device of the present invention can improve light leakage at the peripheral portion of the black display screen when the temperature and humidity change or the liquid crystal display device is continuously lit. Furthermore, a polarizing plate including a retardation plate effective as a λ / 4 plate having a high optical compensation function as a protective film can be obtained. In addition, the viewing angle compensation effect is excellent.

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

  Further, “orthogonal” means that the angle is within a strict angle of less than ± 10 °. In this range, an error from a strict angle is preferably less than ± 5 °, and more preferably less than ± 2 °. Further, “substantially vertical” means within a range of less than ± 20 ° from a strict vertical angle. In this range, an error from a strict angle is preferably less than ± 15 °, and more preferably less than ± 10 °. The “slow axis” means a direction in which the refractive index is maximum in the film plane. Further, the measurement wavelength of refractive index and retardation is a value at λ = 550 nm in the visible light region unless otherwise specified.

  In this specification, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction at a certain wavelength λ nm. Re is measured with KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) by making light of wavelength λ nm incident in the normal direction of the film. Rth was measured by making light having a wavelength λ nm incident from a direction inclined + 40 ° with respect to the normal direction of the film with the slow axis in the plane (determined by KOBRA 21ADH) as the tilt axis (rotation axis). The retardation value and the retardation value measured by making light of wavelength λ nm incident from a direction inclined by -40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis (rotation axis) in three directions in total. KOBRA 21ADH is calculated based on the measured retardation value, the assumed value of average refractive index, and the input film thickness value. 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. Those whose average refractive index is not known can be measured with an Abbe refractometer.

<Adhesive layer>
First, the adhesive layer relating to the present invention will be described.
When the liquid crystal display device is left under high temperature, when the environment is changed from high temperature and high humidity to low temperature and low humidity, or when the backlight is continuously displayed, the dimensional change of the polarizing plate occurs. Accordingly, foaming of the adhesive layer and peeling from the adherend such as a liquid crystal cell are likely to occur. Conventional pressure-sensitive adhesive layers have been improved so that the pressure-sensitive adhesive layer can be used under severe conditions as described above by increasing the molecular weight of the pressure-sensitive adhesive or increasing the degree of crosslinking.

  On the other hand, as in the TN mode which is one of the display modes of the liquid crystal display device, the absorption axes of the polarizing plates on the front and back of the liquid crystal cell are orthogonal to each other, and the absorption axis forms 45 degrees with the long side or the short side of the liquid crystal cell. In a liquid crystal display device, there is a problem in that light leaks at the periphery of the screen of the liquid crystal display device due to concentration of the internal stress caused by the dimensional change of the polarizing plate in the long-term use of the polarizing plate at the periphery of the polarizing plate. It has become. This light leakage can be improved by relaxing the internal stress due to the dimensional change of the polarizing plate, and such relaxation has been realized by making the adhesive layer follow the dimensional change of the polarizing plate.

  However, in the liquid crystal display polarizing plate in which the absorption axes of the polarizing plates on the front and back of the liquid crystal cell are orthogonal to each other and the absorption axis is parallel to the long side or the short side of the liquid crystal cell as in the VA mode, It has been clarified that the light leakage at the periphery of the screen due to the above can be improved by hardening the adhesive layer for attaching the polarizing plate to the glass plate of the liquid crystal cell.

  However, if the pressure-sensitive adhesive layer is hardened as described above, the pressure-sensitive adhesive force is reduced, and foaming or peeling occurs under severe conditions. This time, the inventors of the present invention harden the adhesive layer by three-dimensionally cross-linking (gelling) the adhesive layer, preventing dimensional change of the polarizing plate, and having a low Tg when homopolymer is used, that is, soft. It has been found that the adhesive strength can be secured by using (meth) acrylic acid ester. In addition, the balance between adhesion performance and hardness as described above is molecular weight distribution (ratio of high molecular weight component to low molecular weight component), composition ratio of monomer components (low Tg, high Tg) constituting the copolymer, three-dimensional crosslinking. It can be adjusted by the degree (gel fraction).

[(Meth) acrylic copolymer: (A) {and A ₁ and A ₂ }]
(A ₁ ) (a ₁₁ ) (a ₂₁ ) (Meth) acrylic acid ester monomer having a Tg of less than −30 ° C. when the homopolymer is used In order to relieve internal stress, the Tg of the homopolymer is − A (meth) acrylic acid ester monomer of less than 30 ° C. is used. It is preferably less than -40 ° C, more preferably less than -50 ° C. Examples of (meth) acrylic acid esters having a Tg of less than −30 ° C. include ethyl acrylate, propyl acrylate, n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, and n-nonyl. Acrylate, n-decyl acrylate, 2-methoxyethyl acrylate, ethoxymethyl acrylate, 2-ethoxyethyl acrylate, 3-ethoxypropyl acrylate, n-octyl methacrylate, n-nonyl methacrylate, n-decyl methacrylate, n-undecacil methacrylate , N-dodecyl methacrylate, n-dodecyl methacrylate and the like.

(A ₂ ) (a ₁₂ ) (a ₂₂ ) Compound having a vinyl group having a Tg of −30 ° C. or higher when a homopolymer is used , I-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, benzyl acrylate, n-undecyl acrylate, n-dodecyl acrylate, n-tridecyl acrylate, n-tetradecyl acrylate, n-pentadecyl acrylate, n-hexa Decyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, cyclohexylme Acrylate, benzyl methacrylate, n- heptyl methacrylate, n- tetradecyl methacrylate, n- pentadecyl methacrylate, (meth) acrylates such as n- hexadecyl methacrylate. Examples of other vinyl compounds include vinyl acetate, styrene, methyl styrene, vinyl toluene, acrylonitrile, (meth) acrylamide, and N-methyl acrylamide.

[Measurement of Tg]
Tg in the case of a homopolymer was measured using a differential thermal scanning calorimeter (DSC 2910, manufactured by TA Instruments). The polymer was put in an aluminum pan, the temperature was increased from −160 ° C. to + 100 ° C. at 10 ° C./min, and then the temperature was decreased from + 100 ° C. to −160 ° C. at 10 ° C./min, and Tg was obtained from the data of the temperature decrease process. .

In the present invention, the repeating unit RU _S derived from the above (meth) acrylic acid ester having a Tg of less than −30 ° C. and a vinyl compound having a Tg of −30 ° C. or higher. The ratio of the unit RU _H is a mass ratio of the monomer units, and is RU _S 75 parts by mass or more and RU _H 25 parts by mass or less. RU _S may be RU _H 0 parts by 100 parts by weight, but in the present invention, and (meth) acrylic acid ester Tg is lower than -30 ° C. above in the case of a homopolymer, a Tg of -30 ° C. A copolymer of the above vinyl compounds is preferred. Thereby, the cohesiveness of the pressure-sensitive adhesive layer can be increased, and the performance of the pressure-sensitive adhesive layer such as pressure-sensitive adhesiveness, water resistance, transparency, and workability can be improved.
Furthermore, RU _{S is} 85 parts by mass or more and preferably RU _H 15 parts by mass or less, and most preferably RU _S 95 parts by mass or more and RU _H 5 parts by mass or less.

(A ₃ ) (a ₁₃ ) (a ₂₃ ) Functional group-containing monomer having reactivity with polyfunctional compound (B) Examples of functional group-containing monomers having reactivity with polyfunctional compounds include: Monomers containing carboxyl groups such as (meth) acrylic acid, β-carboxyethyl acrylate, itaconic acid, crotonic acid, maleic acid, maleic anhydride and butyl maleate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl Monomers containing hydroxyl groups such as (meth) acrylate, 4-hydroxybutyl (meth) acrylate, chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate and allyl alicol; aminomethyl (meth) acrylate, Dimethylaminomethyl (meth) acrylate Monomers containing amino groups such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate and vinylpyridine; monomers containing epoxy groups such as glycidyl (meth) acrylate and acetoacetoxyethyl (meth) acrylate And monomers containing an acetoacetyl group. These can be used alone or in combination.
Among these, a monomer containing a carboxyl group and a monomer containing a hydroxyl group are preferable.

In the present invention, the (meth) acrylic copolymer (A) {and (A ₁ ) and (A ₂ ) described later} as the main component of the composition of the (meth) acrylic copolymer forming the adhesive layer Is a (meth) acrylic acid ester (a ₁ ) {or (a ₁₁ ), (a ₂₁ )} having a Tg of less than −30 ° C. and a vinyl compound having a Tg of −30 ° C. or higher. (A ₂ ) {or (a ₁₂ ), (a ₂₂ )} of 10 parts by mass or less, preferably 0.5 to 10 parts by mass with respect to the polyfunctional compound (B) to be described later It is a copolymer with a reactive functional group-containing monomer (a ₃ ) {or (a ₁₃ ), (a ₂₃ )}.

(Meth) acrylic acid ester (a ₁ ) {or (a ₁₁ ), (a ₂₁ )} and vinyl compound (a ₂ ) {or (a ₁₂ ), (a ₂₂ )} in the amounts as described above, By copolymerizing the functional group-containing monomer (a ₃ ) {or (a ₁₃ ), (a ₂₃ )} having reactivity with the polyfunctional compound, it is possible to bond with the polyfunctional compound (B). A copolymer composition having adhesiveness can be formed.

[Polyfunctional compound: (B)]
The pressure-sensitive adhesive layer for polarizing plates of the present invention contains a polyfunctional compound (B) having a reactive functional group.
The functional group possessed by this compound reacts with the functional group having the reactivity of the (meth) acrylic polymer (A) {and (A ₁ ), (A ₂ )} and is functional within one molecule. It has at least 2, preferably 2 to 4 groups.

  Examples of such polyfunctional compounds (B) include isocyanate compounds, epoxy compounds, amine compounds, metal chelate compounds, and aziridine compounds.

  Examples of isocyanate compounds include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane trisene. Examples thereof include adducts such as isocyanate, polymethylene polyphenyl isocyanate, and polyols such as trimethylolpropane.

  Examples of the epoxy compound include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether. , Trimethylolpropane triglycidyl ether, diglycidylaniline, diglycidylamine, N, N, N ′, N′-tetraglycidyl-m-xylenediamine and 1,3-bis (N, N′-diglycidylaminomethyl) A cyclohexane etc. can be mentioned.

  Furthermore, examples of amine compounds include amino resins such as hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethyltetramine, isophoronediamine, urea resin, melamine resin, and methylene resin. .

  Still further, examples of metal chelate compounds include compounds in which polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium are coordinated to acetylacetone or ethyl acetoacetate. And so on.

  Further, examples of the aziridine-based compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxide), N, N′-toluene-2,4-bis (1-aziridinecarboxamide), Triethylenemelamine, bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxyde), tri Mention may be made of methylolpropane-tri-β-aziridinylpropionate and tetramethylolmethane-tri-β-aziridinylpropionate.

  In addition, dialdehyde, methylol polymer, acids, acid anhydrides, amine acids and the like can be used.

Such a polyfunctional compound (B) is usually 0.01 with respect to 100 parts by mass of the high molecular weight (meth) acrylic copolymer (A) {or (A ₁ ), (A ₂ )}. Used in an amount of ~ 1.5 parts by weight. By using the polyfunctional compound (B) in such an amount, a suitable three-dimensional crosslinked structure is formed with the high molecular weight (meth) acrylic copolymer. In addition, these polyfunctional compounds (B) can be used individually or in combination.

[Production of (meth) acrylic copolymer]
Any known method can be adopted for producing the (meth) acrylic copolymer (A) constituting the pressure-sensitive adhesive layer for polarizing plate of the present invention.

For example, a high molecular weight (meth) acrylic copolymer (A ₁ ) having a mass average molecular weight of 1,000,000 or more is from 0.01 to 1 part by mass of a polymerization initiator (azobisisobiate) _per 100 parts by mass of the raw material monomer. Azo polymerization initiators such as tyronitrile and azobiscyclohexanecarbonitrile, peroxides such as benzoyl peroxide and acetyl peroxide, diphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, etc. And a polymerization method such as bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization, and preferably by solution polymerization.

  In the case of the solution polymerization method, ethyl acetate, toluene, hexane, acetone or the like is used as a polymerization solvent, the reaction temperature is 50 to 150 ° C., preferably 50 to 110 ° C., the reaction time is 3 to 15 hours, preferably 5 to 10 It's time.

In addition, the low molecular weight (meth) acrylic (co) polymer (A ₂ ) having a polymerization average molecular weight of 100,000 or less is a block polymerization, solution polymerization, emulsion polymerization as in the case of the high molecular weight acrylic copolymer (A ₁ ). And synthesized by a method such as suspension polymerization, preferably by solution polymerization. However, in order to make the mass average molecular weight 100,000 or less, the amount of the polymerization initiator used is about 10 to 100 times that of the high molecular weight acrylic copolymer, and more preferably lauryl mercaptan, n-dodecyl mercaptan, n-octyl. Chain transfer agents such as mercaptans such as mercaptans, α-methylstyrene dimers and limonene are used.

[Adhesive for polarizing plate]
The pressure-sensitive adhesive for polarizing plates of the present invention can be produced by mixing the (meth) acrylic copolymer (A) and polyfunctional compound (B) produced as described above. As (A), either (A ₁ ) or (A ₂ ) may be used.
The pressure-sensitive adhesive for polarizing plates of the present invention comprises a high molecular weight (meth) acrylic copolymer (A ₁ ) and a low molecular weight (meth) acrylic (co) polymer (A ₂ ) produced as described above. And it can manufacture by mixing a polyfunctional compound (B). That is, both (A ₁ ) and (A ₂ ) may be used as (A).
At this time, the low molecular weight (meth) acrylic (co) polymer (A ₂ ) is ₂₀ to 200 parts by mass, preferably 100 parts by mass with respect to 100 parts by mass of the high molecular weight (meth) acrylic copolymer (A ₁ ). 30-150 parts by mass; the polyfunctional compound (B) is 0.01-1.5 parts by mass, preferably 100 parts by mass of the high molecular weight (meth) acrylic copolymer (A ₁ ), preferably It is contained in an amount of 0.01 to 1.0 part by mass.

In addition to using (meth) acrylic acid ester having a low Tg when homopolymer is used, internal stress is relaxed by creating a three-dimensional crosslinked structure with a high molecular weight (meth) acrylate copolymer (A ₁ ). Japanese Patent No. 3533589 describes that the low molecular weight (meth) acrylate copolymer (A ₂ ) can move (slide) in the three-dimensional crosslinked structure. In the present invention, the degree of relaxation of the internal stress is such that the (meth) acrylic copolymer (A ₁ ) having a high molecular weight (mass average molecular weight of 1 million or more) and a low molecular weight (mass average molecular weight is 100,000). The following formula (1) can be adjusted by the introduction amount of repeating units derived from the functional group-containing monomers (a ₁₃ ) and (a ₂₃ ) in the (meth) acrylic copolymer (A ₂ ): It is preferable to set it as the functional group distribution rate defined by 0 = 0-15 mass%, and it is still more preferable to set it as 0-10 mass%.
Formula (1): Functional group partition ratio = [mass of repeating unit derived from functional group-containing monomer (a ₂₃ ) in [(meth) acrylic copolymer (A ₂ ) / (meth) acrylic copolymer] The mass of the repeating unit derived from the functional group-containing monomer (a ₁₃ ) in (A ₁ )] × 100.

The degree of three-dimensional crosslinking (gel fraction) is 40% by mass or more and 90% by mass or less, and preferably 60% by mass or more and 90% by mass or less in the pressure-sensitive adhesive. More preferably, it is 70 mass% or more and 90 mass% or less.
By setting it within the above-mentioned range, it is possible to adjust the balance between adhesion performance and relaxation more significantly, which is preferable. The degree of three-dimensional crosslinking can be adjusted by the amount of the polymerizable monomer having reactivity with the polyfunctional compound and the amount of the polyfunctional compound.

As described above, the pressure-sensitive adhesive for polarizing plate of the present invention comprises (meth) acrylic copolymer (A) {or high molecular weight (meth) acrylic copolymer (A ₁ ) and low molecular weight (meth) acrylic ( The main component is a composition of a (meth) acrylic copolymer comprising a (co) polymer (A ₂ )} and a polyfunctional compound (B). Weathering stabilizers, tackifiers, plasticizers, softeners, dyes, pigments, silane coupling agents, and inorganic fillers such as conductive fine particles and light scattering fine particles can be added.

  The glass transition temperature of the (meth) acrylic copolymer (A) is preferably 0 ° C. or lower, more preferably −80 to −5 ° C., particularly preferably −60 to −10 ° C. . If the glass transition temperature of the (meth) acrylic copolymer (A) is too high, the adhesive layer has a low resistance to foaming of the pressure-sensitive adhesive layer at a high temperature and resistance to cohesive failure during peeling. On the contrary, if the glass transition point is too low, the adhesive force is increased, but the resistance to cohesive failure at the time of foaming or peeling of the pressure-sensitive adhesive layer at a high temperature is lowered. Therefore, it is necessary to adjust to the above glass transition temperature in order to balance the adhesive strength and the resistance to cohesive failure at the time of foaming or peeling of the pressure-sensitive adhesive layer.

  The thickness of the adhesive layer is preferably 5 to 30 μm, more preferably 15 to 30 μm.

<Physical properties of adhesive layer>
(Creep amount)
The adhesive layer is preferably bonded to an alkali-free glass plate with an area of 10 mm in width and 10 mm in length, and the creep amount after applying a load of 200 g for 1 hour in an atmosphere at 25 ° C. is preferably less than 40 μm. Is less than 30 μm.

(90 ° peel adhesion)
The 90 ° peel adhesive strength of the pressure-sensitive adhesive layer to the alkali-free glass plate in an atmosphere at 25 ° C. is preferably 10 N / 25 mm width or more, and more preferably 13 N / 25 mm width or more.

(Peel adhesion at high temperature)
The 90 ° peel adhesion after treatment for 5 hours in an atmosphere of 70 ° C. with respect to the alkali-free glass plate of the adhesive layer is preferably 10 N / 25 mm width or more at any measurement temperature of 0 to 90 ° C. More preferably, it is 13 N / 25 mm width or more.

(Elastic modulus)
The elastic modulus at 25 ° C. of the adhesive layer is preferably 0.08 MPa or more, and more preferably 0.09 MPa or more. Moreover, it is preferable that the elasticity modulus in 90 degreeC is 0.06 MPa or more, More preferably, it is 0.065 MPa or more.

(Shear modulus)
The adhesive layer has a shear elastic modulus of preferably 0.1 GPa to 100 GPa, more preferably 1 GPa to 30 GPa.

<Protective film>
The polarizing plate of the present invention has protective films on both sides of the polarizer. As the protective film, any protective film normally used as a protective film for a polarizing plate can be used. In the present invention, it is preferable to use a transparent support such as a cellulose acylate film or a cycloolefin polymer. One of the protective films is a retardation plate having at least two optically anisotropic layers, and at least one of the optically anisotropic layers contains at least one liquid crystal compound. It is also preferable that not only one of the protective films but also both are retardation plates. In this case, it is preferable that the retardation plate disposed on the opposite surface of the polarizer to the retardation plate is composed of an optically anisotropic layer containing at least one liquid crystal compound. The phase difference plate disposed in the polarizer may have different optical characteristics.
Moreover, the composition of the protective film on both sides of the polarizer may be the same or different. For example, among the protective films on both sides of the polarizer, the aforementioned cellulose acylate film can be used on one side, and a cycloolefin-based polymer on the other side. Also, films having different compositions and different optical characteristics can be used. Furthermore, it is good also as a protective film by providing a polymer layer on a cellulose acylate film, a cycloolefin type polymer film, etc. For example, a polyimide layer can be provided on a cellulose acylate film to form a protective film.

[Phase difference plate]
These retardation plates in the present invention are composed of a composition containing at least one liquid crystalline compound, and include an optically anisotropic layer formed by fixing molecules of the liquid crystalline compound in an aligned state. The retardation plate preferably has an in-plane retardation value and a retardation value in the thickness direction as Re and Rth, respectively, and Nz is smaller than 0 when Nz is defined as in the following formula (2). Nz is more preferably −5 to −0.1, still more preferably −4.5 to −0.2, still more preferably −4 to −0.3, and −4 to -1.0 is most preferred.
Nz = 0.5 + Rth / Re (2)
The retardation value measured from the normal direction of the retardation plate plane is Re (0), and the retardation value measured by tilting the retardation plate by 40 ° is set with the slow axis of the retardation plate as the tilt axis. Re (40), Re (0), Re (40), Re (−40) where Re (−40) is a retardation value measured by tilting the retardation plate by 40 ° in the direction opposite to the tilt direction. ) And the thickness and average refractive index of the retardation plate, the refractive index (Rth) in the thickness direction can be calculated.

  In the retardation plate of the present invention, Re is preferably 50 to 200 nm, more preferably 70 to 180 nm, still more preferably 80 to 160 nm, and most preferably 90 to 160 nm. Further, it is preferable that the Re (40) and Re (−40) are substantially equal. The difference between Re (40) and Re (−40) is more preferably 0 nm. However, in consideration of measurement error and the like, in this specification, the difference is substantially equal to the range of 4 nm. To do.

It is also preferable that the retardation plate in the present invention has a broadband property in which Re increases as the wavelength increases. For example, there is a technique for laminating a layer having a Re of substantially ½ wavelength and a layer having a Re of substantially ¼ wavelength so that their slow axes intersect in order to develop broadband characteristics. It is disclosed in Japanese Patent Application Laid-Open No. 2000-284126. In addition, a technique for developing broadband properties by stretching a modified polycarbonate film is disclosed in International Publication No. WO 00/26705. A broadband retardation plate having a desired Re is manufactured by these techniques, and a refractive index in a three-dimensional direction is controlled so as to satisfy the above formula (2) by laminating an optically anisotropic layer containing a liquid crystal compound. be able to.
Rth is preferably −1000 to −20 nm, more preferably −800 to −30 nm, further preferably −600 to −40 nm, and particularly preferably −300 to −100 nm. .

[Optically Anisotropic Layer Containing Liquid Crystalline Compound]
The retardation plate in the present invention preferably includes at least an optically anisotropic layer containing at least one liquid crystalline compound. As long as the optical characteristics are satisfied, the type of the liquid crystalline compound is not particularly limited. For example, after forming a low molecular weight liquid crystalline compound in a nematic orientation in a liquid crystal state, an optically anisotropic layer obtained by fixing by photocrosslinking or thermal crosslinking, or after forming a polymer liquid crystalline compound in a nematic orientation in a liquid crystal state, An optically anisotropic layer obtained by fixing the orientation by cooling can also be used. In the present invention, even when a liquid crystalline compound is used for the optically anisotropic layer, the optically anisotropic layer is a layer formed by fixing the liquid crystalline compound by polymerization or the like. After that, it is no longer necessary to show liquid crystallinity. The polymerizable liquid crystal compound may be a polyfunctional polymerizable liquid crystal or a monofunctional polymerizable liquid crystal compound. The liquid crystalline compound may be a discotic liquid crystalline compound or a rod-shaped liquid crystalline compound.

It is preferable that at least one of the protective films of the polarizing film is a retardation plate having at least two optically anisotropic layers, and the other is a retardation plate having at least one optically anisotropic layer. The optically anisotropic layer may consist of only one layer, or may be a laminate of two or more optically anisotropic layers. In order to arbitrarily control the refractive index anisotropy in the three-dimensional direction, it becomes easier to stack two or more optically anisotropic layers. For example, the first optical anisotropic layer is formed in order to set Re to a desired value, and the second optical anisotropic layer is formed in order to adjust Rth, thereby satisfying the above formula (2). A retardation plate can be produced.
The following is a preferred embodiment in the case where at least two optically anisotropic layers containing a liquid crystalline compound are included (the optically anisotropic layer 1 is a lower layer and the optically anisotropic layer 2 is an upper layer).

  The liquid crystalline compound used for the first optically anisotropic layer may be a discotic liquid crystalline compound or a rod-shaped liquid crystalline compound. If the retardation plate satisfies the above formula (2), the alignment state of the liquid crystal compound may be any of vertical alignment, horizontal alignment, hybrid alignment, and tilt alignment. In order to produce a retardation plate having a symmetric viewing angle dependency, it is preferable that the long axis of the rod-like liquid crystal compound is substantially horizontal to the film surface (optically anisotropic layer surface). More preferably, the disc surface of the tick liquid crystalline compound is substantially perpendicular to the film surface (optically anisotropic layer surface). The term “substantially perpendicular to the discotic liquid crystalline compound” means that the angle formed by the film surface (optically anisotropic layer surface) and the disc surface of the discotic liquid crystalline compound is in the range of 70 ° to 90 °. . The tilt orientation may be such that the average tilt angle of the disk surface falls within this range, or hybrid orientation in which the tilt angle gradually changes may be used. Even in the case of tilt orientation or hybrid orientation, the average tilt angle is preferably 70 ° to 90 °, more preferably 80 ° to 90 °, and even more preferably 85 ° to 90 °. That the rod-like liquid crystalline compound is substantially horizontal means that the angle formed by the film surface (optically anisotropic layer surface) and the director of the rod-like liquid crystalline compound is in the range of 0 ° to 20 °. The rod-like liquid crystal compound may be tilted so that the average tilt angle falls within this range, or may be hybrid-aligned so that the tilt angle gradually changes. Even in the case of tilted orientation or hybrid orientation, the average tilt angle is preferably 0 ° to 20 °, more preferably 0 ° to 10 °, and even more preferably 0 ° to 5 °.

  The liquid crystalline compound used in the second optically anisotropic layer may be a discotic liquid crystalline compound or a rod-shaped liquid crystalline compound. If the retardation plate satisfies the above formula (2), the alignment state of the liquid crystal compound may be any of vertical alignment, horizontal alignment, hybrid alignment, and tilt alignment. For controlling the Rth of the phase plate, it is preferable to use a rod-like liquid crystalline compound, and it is more preferred that the major axis of the rod-like liquid crystalline compound is substantially perpendicular to the film surface (optically anisotropic layer surface). That the rod-like liquid crystalline compound is substantially perpendicular means that the angle formed by the film surface (optically anisotropic layer surface) and the director of the rod-like liquid crystalline compound is in the range of 70 ° to 90 °. Tilt orientation may be performed so that the average tilt angle falls within this range, or hybrid orientation may be performed so that the tilt angle gradually changes. Even in the case of tilt alignment or hybrid alignment, the average tilt angle of the rod-like liquid crystal compound is preferably 70 ° to 90 °, more preferably 80 ° to 90 °, and still more preferably 85 ° to 90 °.

  The optically anisotropic layer supports a coating liquid containing a liquid crystal compound such as a rod-like liquid crystal compound or a discotic liquid crystal compound and, if desired, the following polymerization initiator, air interface alignment agent, and other additives. It can be formed by applying on the body. It is preferable to form an alignment film on a support and apply the coating solution on the surface of the alignment film.

[Discotic liquid crystalline compounds]
In the present invention, the optically anisotropic layer is preferably formed using a discotic liquid crystalline compound. Discotic liquid crystalline compounds are disclosed in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by The Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J Am.Chem.Soc., Vol.116, page 2655 (1994)). The polymerization of discotic liquid crystalline compounds is described in JP-A-8-27284.

The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a discotic core of a discotic liquid crystalline compound can be considered. However, when a polymerizable group is directly connected to the discotic core, the alignment state is maintained in the polymerization reaction. It becomes difficult. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula.
D (-LP) _n
In the formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12. Preferred specific examples of the discotic core (D), divalent linking group (L) and polymerizable group (P) in the above formula are (D1) to (D15) described in JP-A No. 2001-4837, respectively. ), (L1) to (L25), (P1) to (P18), and the contents described in the publication can be preferably used. In addition, the discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystal compound is preferably 70 to 300 ° C, and more preferably 70 to 170 ° C.

[Bar-shaped liquid crystalline compound]
In the present invention, it is preferable to form an optically anisotropic layer using a rod-like liquid crystalline compound. Examples of rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. Not only the above low-molecular liquid crystalline compounds but also high-molecular liquid crystalline compounds can be used. It is more preferable to fix the alignment of the rod-like liquid crystal compound by polymerization. As the liquid crystalline compound, those having a partial structure capable of causing polymerization or crosslinking reaction by actinic rays, electron beams, heat, or the like are suitably used. The number of the partial structures is preferably 1 to 6, more preferably 1 to 3. As the polymerizable rod-like liquid crystalline compound, Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 5,622,648, and 5,770,107, International Publication WO95 / 22586. No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, and No. 7-110469. 11-80081 and JP-A 2001-328773, and the like can be used.

[Vertical alignment accelerator]
In order to uniformly and vertically align the discotic liquid crystalline compound and the rod-shaped liquid crystalline compound, it is necessary to vertically control the liquid crystalline compound on the alignment film interface side and the air interface side. For this purpose, a composition obtained by adding a compound having an effect of vertically aligning a liquid crystalline compound by an excluded volume effect, an electrostatic effect, or a surface energy effect to the alignment film may be employed. In addition, with regard to alignment control on the air interface side, a compound that is unevenly distributed at the air interface during alignment of the liquid crystalline compound and acts to align the liquid crystalline compound vertically by its excluded volume effect, electrostatic effect, or surface energy effect is blended The composition (hereinafter sometimes simply referred to as “liquid crystal composition”) may be employed. As such a compound (alignment film interface side vertical alignment agent) that promotes the vertical alignment of the molecules of the liquid crystal compound on the alignment film interface side, a pyridinium derivative is preferably used. As a compound (air interface side vertical alignment agent) that promotes the vertical alignment of the molecules of the liquid crystal compound on the air interface side, a fluoro aliphatic group that promotes the uneven distribution of the compound on the air interface side, One or more hydrophilic groups selected from the group consisting of a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ }, and salts thereof A compound is preferably used. Further, by blending these compounds, for example, when a liquid crystalline composition is prepared as a coating solution, the coating property of the coating solution is improved, and the occurrence of unevenness and repellency is suppressed. The vertical alignment agent will be described in detail below.

[Alignment film interface side vertical alignment agent]
As the alignment film interface-side vertical alignment agent that can be used in the present invention, a pyridinium derivative (pyridinium salt) represented by the following formula (I) is preferably used. By adding at least one of the pyridinium derivatives to the liquid crystalline composition, the molecules of the discotic liquid crystalline compound can be aligned substantially vertically in the vicinity of the alignment film.

In the formula (I), L ¹ represents a divalent linking group, an alkylene group and —O—, —S—, —CO—, —SO ₂ —, —NR ^a — (where R ^a is the number of carbon atoms. Is an alkyl group or a hydrogen atom having 1 to 5), an alkenylene group, an alkynylene group or an arylene group, and preferably a divalent linking group having 1 to 20 carbon atoms. The alkylene group may be linear or branched.

In the formula (I), R ¹ is a hydrogen atom, an unsubstituted amino group, or a substituted amino group substituted with a substituent having 1 to 20 carbon atoms. When R ¹ is a substituted amino group, it is preferably substituted with an aliphatic group. Examples of the aliphatic group include an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an alkynyl group, and a substituted alkynyl group. When R ¹ is a disubstituted amino group, two aliphatic groups may be bonded to each other to form a nitrogen-containing heterocyclic ring. The nitrogen-containing heterocycle formed at this time is preferably a 5-membered ring or a 6-membered ring. R ¹ is preferably a hydrogen atom, an unsubstituted amino group or a substituted amino group having 1 to 20 carbon atoms, and is a hydrogen atom, an unsubstituted amino group or a substituted amino group having 2 to 12 carbon atoms. More preferably, it is more preferably a hydrogen atom, an unsubstituted amino group, or a substituted amino group having 2 to 8 carbon atoms. When R ¹ is an amino group, it is preferably substituted at the 4-position of the pyridinium ring.

  In the formula (I), X is an anion. Examples of anions include halogen anions (for example, fluorine ions, chlorine ions, bromine ions, iodine ions, etc.), sulfonate ions (for example, methanesulfonate ions, trifluoromethanesulfonate ions, methylsulfate ions, p-toluene). Sulfonate ion, p-chlorobenzenesulfonate ion, 1,3-benzenedisulfonate ion, 1,5-naphthalenedisulfonate ion, 2,6-naphthalenedisulfonate ion, sulfate ion, carbonate ion, nitrate ion, thiocyanate Examples include acid ions, perchlorate ions, tetrafluoroborate ions, picrate ions, acetate ions, formate ions, trifluoroacetate ions, phosphate ions (for example, hexafluorophosphate ions), and hydroxide ions. X is preferably a halogen anion, a sulfonate ion, or a hydroxide ion.

In the formula (I), Y ¹ is a divalent linking group having 1 to 30 carbon atoms having a 5-membered or 6-membered ring as a partial structure. The cyclic partial structure contained in Y ¹ is more preferably a cyclohexyl ring, an aromatic ring or a heterocyclic ring. Examples of the aromatic ring include a benzene ring, an indene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, a biphenyl ring, and a pyrene ring. More preferred are a benzene ring, a biphenyl ring, and a naphthalene ring. The hetero atom constituting the hetero ring is preferably a nitrogen atom, an oxygen atom or a sulfur atom. For example, a furan ring, thiophene ring, pyrrole ring, pyrroline ring, pyrrolidine ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole Ring, imidazole ring, imidazoline ring, imidazolidine ring, pyrazole ring, pyrazoline ring, pyrazolidine ring, triazole ring, furazane ring, tetrazole ring, pyran ring, dioxane ring, dithiane ring, thiine ring, pyridine ring, piperidine ring, oxazine ring Morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring and triazine ring. The heterocycle is preferably a 6-membered ring. The divalent linking group having a 5-membered or 6-membered ring represented by Y as a partial structure may have a substituent.

In the formula (I), Z represents a halogen-substituted phenyl group, a nitro-substituted phenyl group, a cyano-substituted phenyl group, a phenyl group substituted with an alkyl group having 1 to 10 carbon atoms, or an alkoxy having 2 to 10 carbon atoms. A phenyl group substituted with a group, an alkyl group having 1 to 12 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxy having 2 to 13 carbon atoms A carbonyl group, an aryloxycarbonyl group having 7 to 26 carbon atoms, an arylcarbonyloxy group having 7 to 26 carbon atoms, a cyano-substituted phenyl group, a halogen-substituted phenyl group, and an alkyl having 1 to 10 carbon atoms. Phenyl group substituted with a group, phenyl group substituted with an alkoxy group having 2 to 10 carbon atoms, aryloxycarboe having 7 to 26 carbon atoms Le group or carbon atoms is preferably an aryl carbonyl group having 7 to 26.
Z may further have a substituent. Examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a cyano group, a nitro group, and a carbon atom number of 1 to 16. An alkyl group having 1 to 16 carbon atoms, an alkynyl group having 1 to 16 carbon atoms, a halogen-substituted alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, An acyl group having 2 to 16 carbon atoms, an alkylthio group having 1 to 16 carbon atoms, an acyloxy group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, a carbon atom An alkyl-substituted carbamoyl group having 2 to 16 carbon atoms and an acylamino group having 2 to 16 carbon atoms are included.

  The pyridinium compound used in the present invention is preferably a pyridinium compound represented by the following formula (Ia).

In the formula (Ia), L ³ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═. CH—, —N═N—, —O—AL—O—, —O—AL—O—CO—, —O—AL—CO—O—, —CO—O—AL—O—, —CO—. O-AL-O-CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-CO-AL-O-CO- or -O-CO-AL- CO-O-. AL is an alkylene group having 1 to 10 carbon atoms. L ³ represents a single bond, —O—, —O—AL—O—, —O—AL—O—CO—, —O—AL—CO—O—, —CO—O—AL—O—, — CO-O-AL-O-CO-, -CO-O-AL-CO-O-, -O-CO-AL-O-, -O-CO-AL-O-CO- or -O-CO- AL-CO-O- is preferable, and a single bond or -O- is more preferable.

In the formula (Ia), L ⁴ represents a single bond, —O—, —O—CO—, —CO—O—, —C≡C—, —CH═CH—, —CH═N—, —N═. CH- or -N = N-.

In the formula (Ia), R ³ is a hydrogen atom, an unsubstituted amino group, or an alkyl-substituted amino group having 2 to 20 carbon atoms. When R ³ is a dialkyl-substituted amino group, two alkyl groups may be bonded to each other to form a nitrogen-containing heterocycle. The nitrogen-containing heterocycle formed at this time is preferably a 5-membered ring or a 6-membered ring. R ³ is more preferably a hydrogen atom, an unsubstituted amino group or a dialkyl-substituted amino group having 2 to 12 carbon atoms, most preferably a hydrogen atom, an unsubstituted amino group or a dialkyl-substituted amino group having 2 to 8 carbon atoms. . When R ³ is an unsubstituted amino group, the 4-position of the pyridinium ring is preferably amino-substituted.

In the formula (Ia), Y ² and Y ³ are each independently a divalent group consisting of a 6-membered ring which may have a substituent. Examples of the 6-membered ring include an aliphatic ring, an aromatic ring (benzene ring), and a heterocyclic ring. Examples of the 6-membered aliphatic ring include a cyclohexane ring, a cyclohexene ring, and a cyclohexadiene ring. Examples of 6-membered heterocycles include pyran ring, dioxane ring, dithiane ring, thiine ring, pyridine ring, piperidine ring, oxazine ring, morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, piperazine ring and triazine ring. Can be mentioned. Another 6-membered ring or 5-membered ring may be condensed to the 6-membered ring.
Examples of the substituent include a halogen atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms. The alkyl group and the alkoxy group may be substituted with an acyl group having 2 to 12 carbon atoms or an acyloxy group having 2 to 12 carbon atoms. The definition of an acyl group and an acyloxy group will be described later.

In formula (Ia), X ¹ is an anion. X ¹ is preferably a monovalent anion. Examples of anions include halogen anions (eg, fluorine ions, chlorine ions, bromine ions, iodine ions) and sulfonate ions (eg, methanesulfonate ions, p-toluenesulfonate ions, benzenesulfonate ions). It is.

In Formula (Ia), Z ¹ is a hydrogen atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, and each of the alkyl group and the alkoxy group is a carbon atom. It may be substituted with an acyl group having 2 to 12 atoms or an acyloxy group having 2 to 12 carbon atoms.

In the formula (Ia), m is 1 or 2, and when m is 2, two L ⁴ and two Y ³ may be different.
When m is 2, Z ¹ is preferably a cyano group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.
When m is 1, Z ¹ is an alkyl group having 7 to 12 carbon atoms, an alkoxy group having 7 to 12 carbon atoms, an acyl-substituted alkyl group having 7 to 12 carbon atoms, or 7 carbon atoms. An acyl-substituted alkoxy group having -12 carbon atoms, an acyloxy-substituted alkyl group having 7-12 carbon atoms, or an acyloxy-substituted alkoxy group having 7-12 carbon atoms is preferable.

  The acyl group is represented by —CO—R, the acyloxy group is represented by —O—CO—R, and R is an aliphatic group (alkyl group, substituted alkyl group, alkenyl group, substituted alkenyl group, alkynyl group, substituted alkynyl group) or aromatic. Group (aryl group, substituted aryl group). R is preferably an aliphatic group, and more preferably an alkyl group or an alkenyl group.

In formula (Ia), p is an integer of 1-10. C _p H _2p means a chain alkylene group which may have a branched structure. C _p H _2p is preferably a linear alkylene group. Further, p is more preferably 1 or 2.

  Specific examples of the compound represented by formula (I) and / or (Ia) are shown below. Here, Me represents a methyl group.

  A pyridinium derivative is generally obtained by alkylating a pyridine ring (Menstokin reaction).

  The preferable range of the content of the pyridinium derivative in the liquid crystal composition varies depending on the use, but 0.005 in the liquid crystal composition (liquid crystal composition excluding the solvent when prepared as a coating liquid). It is preferably -8% by mass, more preferably 0.01-5% by mass.

[Air interface side vertical alignment agent]
As an air interface side vertical alignment agent usable in the present invention, a fluoro aliphatic group, a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ } And one or more hydrophilic groups selected from the group consisting of the salts thereof, a fluoroaliphatic group-containing polymer (hereinafter referred to as “fluorinated polymer”), or a compound represented by the general formula (III) Fluorine compounds are preferably used.

First, the fluorine polymer will be described.
The fluoropolymer usable in the present invention includes a fluoroaliphatic group, a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a phosphonoxy group {—OP (═O) (OH) ₂ }, and their It contains one or more hydrophilic groups selected from the group consisting of salts. The types of polymers are described in “Revised Chemistry of Polymer Synthesis” (written by Takayuki Otsu, published by Kagaku Dojin Co., 1968) on pages 1 to 4, for example, polyolefins, polyesters, polyamides, polyimides. , Polyurethanes, polycarbonates, polysulfones, polycarbonates, polyethers, polyacetals, polyketones, polyphenylene oxides, polyphenylene sulfides, polyarylates, polytetrafluoroethylene (PTFE), polyvinylidene fluorides And cellulose derivatives. The fluoropolymer is preferably a polyolefin.

  The fluorine-based polymer is a polymer having a fluoroaliphatic group in the side chain. The fluoroaliphatic group preferably has 1 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms. The aliphatic group may be linear or cyclic, and when it is linear, it may be linear or branched. Of these, a linear fluoroaliphatic group having 6 to 10 carbon atoms is preferable. The degree of substitution with fluorine atoms is not particularly limited, but 50% or more of hydrogen atoms in the aliphatic group are preferably substituted with fluorine atoms, and more preferably 60% or more are substituted. The fluoroaliphatic group is contained in a side chain bonded to the polymer main chain via an ester bond, an amide bond, an imide bond, a urethane bond, a urea bond, an ether bond, a thioether bond, an aromatic ring, or the like. One of the fluoroaliphatic groups is derived from a fluoroaliphatic compound produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). Regarding the production method of these fluoroaliphatic compounds, for example, “Synthesis and Function of Fluorine Compounds” (Supervision: Nobuo Ishikawa, Issue: CMC Co., 1987), “Chemistry of Organic Fluorines Compounds”. II "(Monograph 187, Ed by Milos Hudricky and Attila E. Pavlath, American Chemical Society 1995). The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen (example in Scheme-1). showed that).

  The obtained terminal iodinated telomer is usually subjected to appropriate terminal chemical modification such as [Scheme 2], and led to a fluoroaliphatic compound. These compounds are further converted into a desired monomer structure as needed, and used for the production of a fluoropolymer.

  Specific examples of monomers that can be used in the production of the fluorine-based polymer that can be used in the present invention are listed below, but the present invention is not limited to the following specific examples.

  One embodiment of the fluorine-based polymer that can be used in the present invention is represented by a repeating unit derived from a fluoroaliphatic group-containing monomer (hereinafter sometimes referred to as “fluorine-based monomer”) and the following formula (II): It is a copolymer having a repeating unit containing a hydrophilic group.

In the above formula (II), R ¹ , R ² and R ³³ each independently represent a hydrogen atom or a substituent. Q represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof. L represents an arbitrary group selected from the following linking group group, or a divalent linking group formed by combining two or more thereof.
(Linked group group)
Single bond, —O—, —CO—, —NR ^b — (R ^b represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group), —S—, —SO ₂ —, —P (═O) (OR ^f ) — (R ^f represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group, and an arylene group.

In formula (II), R ¹ , R ² and R ³³ each independently represent a hydrogen atom or a substituent selected from the substituent group exemplified below.
(Substituent group)
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, still more preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group and the like, alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, More preferably, it is a C2-C8 alkenyl group, for example, a vinyl group, an aryl group, 2-butenyl group, 3-pentenyl group etc., an alkynyl group (preferably C2-C20, more preferably). Is an alkynyl group having 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, such as a propargyl group or a 3-pentynyl group. An aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, still more preferably 6 to 12 carbon atoms, such as a phenyl group, a p-methylphenyl group, A naphthyl group), an aralkyl group (preferably an aralkyl group having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, still more preferably 7 to 12 carbon atoms, such as a benzyl group, a phenethyl group, A 3-phenylpropyl group), a substituted or unsubstituted amino group (preferably an amino group having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, still more preferably 0 to 6 carbon atoms, For example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, an anilino group, etc.)

An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group); An alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 10 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group), acyloxy A group (preferably an acyloxy group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 10 carbon atoms such as an acetoxy group and a benzoyloxy group), an acylamino group (preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, still more preferably 2 carbon atoms 10 acylamino groups such as acetylamino group and benzoylamino group), alkoxycarbonylamino groups (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 2 carbon atoms). 12 alkoxycarbonylamino groups, for example, a methoxycarbonylamino group and the like, and aryloxycarbonylamino groups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, still more preferably 7 carbon atoms). To 12 aryloxycarbonylamino groups, such as phenyloxycarbonylamino group, and sulfonylamino groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably carbon atoms). 1 to 12 sulfonylamino groups, for example, Sulfonylamino groups, benzenesulfonylamino groups, etc.), sulfamoyl groups (preferably 0-20 carbon atoms, more preferably 0-16 carbon atoms, still more preferably 0-12 carbon atoms sulfamoyl groups, , Sulfamoyl group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group and the like), carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably A carbamoyl group having 1 to 12 carbon atoms, and examples thereof include an unsubstituted carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, and a phenylcarbamoyl group).

An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is a C6-C20, More preferably, it is a C6-C16, More preferably, it is a C6-C12 arylthio group, For example, a phenylthio group etc. are mentioned, A sulfonyl group (preferably C1-C1). 20, more preferably a sulfonyl group having 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, and examples thereof include a mesyl group and a tosyl group), a sulfinyl group (preferably having a carbon number of 1 to 20, and more. A sulfinyl group having 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, is preferable. A ureido group (preferably a benzenesulfinyl group), a ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms. Ureido group, methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, and further preferably having 1 to 12 carbon atoms) Group such as diethyl phosphoramide group and phenylphosphoric acid amide group), hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group Group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably A heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, such as a heterocyclic group having a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom, such as an imidazolyl group, a pyridyl group, or a quinolyl group; Group, furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, More preferably, it is a silyl group having 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group. These substituents may be further substituted with these substituents. Moreover, when it has two or more substituents, they may be the same or different. If possible, they may be bonded to each other to form a ring.

R ¹ , R ² and R ³³ are each independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), or a group represented by -LQ described later. It is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Particularly preferred are a hydrogen atom and an alkyl group having 1 to 2 carbon atoms. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, sec-butyl group and the like. The alkyl group may have a suitable substituent. Examples of the substituent include a halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl Group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamido group, sulfolyl group, carboxyl group and the like. The carbon number of the alkyl group does not include the carbon atom of the substituent. The same applies to the carbon number of other groups.

L represents a divalent linking group selected from the above linking group group, or a divalent linking group formed by combining two or more thereof. In the linking group group, R ^{b in} —NR ^b — represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, preferably a hydrogen atom or an alkyl group. R ^f in —PO (OR ^f ) — represents an alkyl group, an aryl group or an aralkyl group, and preferably an alkyl group. When R ^b and R ^f represent an alkyl group, an aryl group, or an aralkyl group, the number of carbon atoms is the same as that described in the “substituent group”. L preferably contains a single bond, —O—, —CO—, —NR ^b —, —S—, —SO ₂ —, an alkylene group or an arylene group, and includes —CO—, —O—, —NR. It is particularly preferable that ^b- , an alkylene group or an arylene group is contained. When L contains an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 6 carbon atoms. Specific examples of particularly preferable alkylene groups include a methylene group, an ethylene group, a trimethylene group, a tetrabutylene group, and a hexamethylene group. When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and still more preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene groups and naphthalene groups. When L contains a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and still more preferably. 7-16. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group. The group listed as L may have a suitable substituent. As such a substituent, the same substituents as those described above as the substituents for R ¹ , R ² and R ³³ can be exemplified.
The specific structure of L is illustrated below.

  In the formula (II), Q is a carboxyl group, a salt of a carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2-hydroxyethylammonium, tetrabutylammonium, Trimethylbenzylammonium, dimethylphenylammonium, etc.), pyridinium salts, etc.), sulfo groups, salts of sulfo groups (examples of cations forming the salts are the same as those described above for carboxyl groups), phosphonoxy groups, salts of phosphonoxy groups ( Examples of the cation forming the salt are the same as those described for the carboxyl group). A carboxyl group, a sulfo group, and a phospho group are more preferable, and a carboxyl group or a sulfo group is particularly preferable.

  The fluoropolymer may contain one type of repeating unit represented by the formula (II) or two or more types. Moreover, the said fluorine-type polymer may have 1 type (s) or 2 or more types of repeating units other than said each repeating unit. The other repeating units are not particularly limited, and preferred examples thereof include repeating units derived from ordinary radical polymerizable monomers. Hereinafter, specific examples of monomers for deriving other repeating units will be given. The fluoropolymer may contain a repeating unit derived from one or two or more monomers selected from the following monomer group.

Monomer group (1) Alkenes ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-dodecene, 1-octadecene, 1-eicosene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3, 3, 3-trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride, etc .;
(2) Dienes 1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2-n-propyl-1,3-butadiene, 2,3-dimethyl-1,3 -Butadiene, 2-methyl-1,3-pentadiene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, 2-chloro -1,3-butadiene, 1-bromo-1,3-butadiene, 1-chlorobutadiene, 2-fluoro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1,1,2- Trichloro-1,3-butadiene and 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane and the like;

(3) Derivatives of α, β-unsaturated carboxylic acid (3a) Alkyl acrylates Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate , Amyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, tert-octyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 2-bromoethyl acrylate, 4-chlorobutyl acrylate, 2-cyanoethyl acrylate, 2-acetoxyethyl acrylate, methoxybenzyl Chryrate, 2-chlorocyclohexyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 2-methoxyethyl acrylate, ω-methoxypolyethylene glycol acrylate (number of added polyoxyethylene: n = 2 to 100), 3-methoxy Butyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2- (2-butoxyethoxy) ethyl acrylate, 1-bromo-2-methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate, glycidyl acrylate Such);

(3b) Alkyl methacrylates Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2 -Ethylhexyl methacrylate, n-octyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, allyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, cresyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, ω Methoxypolyethylene glycol methacrylate (number of added polyoxyethylene: n = 2 to 100), 2-acetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate Glycidyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanatoethyl methacrylate, etc .;

(3c) Diesters of unsaturated polycarboxylic acids Dimethyl maleate, dibutyl maleate, dimethyl itaconate, dibutyl taconate, dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate, etc .;

(3d) Amides of α, β-unsaturated carboxylic acids N, N-dimethylacrylamide, N, N-diethylacrylamide, Nn-propylacrylamide, N-tertbutylacrylamide, N-tertoctylmethacrylamide, N- Cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-benzylacrylamide, N-acryloylmorpholine, diacetone acrylamide, N-methylmaleimide and the like;

(4) Unsaturated nitriles Acrylonitrile, methacrylonitrile, etc .;
(5) Styrene and its derivatives Styrene, vinyl toluene, ethyl styrene, p-tert butyl styrene, methyl p-vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, vinyl naphthalene, p-methoxy styrene, p-hydroxy Methyl styrene, p-acetoxy styrene, etc .;
(6) Vinyl esters Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, vinyl methoxyacetate, vinyl vinyl acetate, etc .;

(7) Vinyl ethers Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl Vinyl ether, n-eicosyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, fluorobutyl vinyl ether, fluorobutoxyethyl vinyl ether, etc .; and (8) other polymerizable monomers N-vinyl pyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, Methoxyethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline .

  In the fluoropolymer, the amount of the fluoroaliphatic group-containing monomer is preferably 5% by mass or more, more preferably 10% by mass or more, and more preferably 30% by mass or more of the total amount of constituent monomers of the polymer. Is more preferable. In the fluoropolymer, the amount of the repeating unit represented by the formula (II) is preferably 0.5% by mass or more, and 1 to 20% by mass of the total amount of the constituent monomers of the fluoropolymer. More preferably, it is 1 to 10% by mass. Since the above-mentioned mass percentage is likely to vary in a preferable range depending on the molecular weight of the monomer used, the content of the repeating unit represented by the formula (II) is expressed by the number of functional group moles per unit mass of the polymer. Can be defined accurately. When this notation is used, the preferred amount of the hydrophilic group (Q in the formula (II)) contained in the fluoropolymer is 0.1 mmol / g to 10 mmol / g, and the more preferred amount is 0. .2 mmol / g to 8 mmol / g.

  The fluoropolymer used in the present invention has a mass average molecular weight of preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 100,000 or less. The mass average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).

  The polymerization method of the fluorine-based polymer is not particularly limited. For example, a polymerization method such as cation polymerization, radical polymerization, or anion polymerization using a vinyl group can be employed. Polymerization is particularly preferred in that it can be used for general purposes. As the polymerization initiator for radical polymerization, known compounds such as radical thermal polymerization initiators and radical photopolymerization initiators can be used, and it is particularly preferable to use radical thermal polymerization initiators. Here, the radical thermal polymerization initiator is a compound that generates radicals by heating to a decomposition temperature or higher. Examples of such radical thermal polymerization initiators include diacyl peroxide (acetyl peroxide, benzoyl peroxide, etc.), ketone peroxide (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), hydroperoxide (hydrogen peroxide, tert. -Butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyesters (tert-butyl peroxyacetate, tert -Butyl peroxypivalate, etc.), azo compounds (azobisisobutyronitrile, azobisisovaleronitrile, etc.), persulfates (ammonium persulfate, sodium persulfate) Beam, such as potassium sulphate). Such radical thermal polymerization initiators can be used alone or in combination of two or more.

  The radical polymerization method is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method, and the like can be adopted. The solution polymerization, which is a typical radical polymerization method, will be described more specifically. The outlines of other polymerization methods are the same, and details thereof are described, for example, in “Polymer Science Experimental Method” edited by Polymer Society (Tokyo Kagaku Dojin, 1981).

  An organic solvent is used for solution polymerization. These organic solvents can be arbitrarily selected as long as the objects and effects of the present invention are not impaired. These organic solvents are usually organic compounds having boiling points under atmospheric pressure in the range of 50 to 200 ° C., and organic compounds that uniformly dissolve each component are preferred. Examples of preferred organic solvents include alcohols such as isopropanol and butanol; ethers such as dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethyl acetate and acetic acid And esters such as butyl, amyl acetate, and γ-butyrolactone; and aromatic hydrocarbons such as benzene, toluene, and xylene. These organic solvents can be used alone or in combination of two or more. Furthermore, a water-mixed organic solvent in which water is used in combination with the above organic solvent is also applicable from the viewpoint of the solubility of the monomer and the polymer to be produced.

  Also, the solution polymerization conditions are not particularly limited, but for example, it is preferable to heat within a temperature range of 50 to 200 ° C. for 10 minutes to 30 hours. Furthermore, in order not to deactivate the generated radicals, it is preferable to perform an inert gas purge not only during solution polymerization but also before the start of solution polymerization. Usually, nitrogen gas is suitably used as the inert gas.

  In order to obtain the fluoropolymer in a preferable molecular weight range, a radical polymerization method using a chain transfer agent is particularly effective. As chain transfer agents, mercaptans (for example, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, octadecyl mercaptan, thiophenol, p-nonylthiophenol, etc.), polyhalogenated alkyls (for example, carbon tetrachloride, Chloroform, 1,1,1-trichloroethane, 1,1,1-tribromooctane, etc.) and low-activity monomers (α-methylstyrene, α-methylstyrene dimer, etc.) can be used, but preferably It is a mercaptan having 4 to 16 carbon atoms. The amount of these chain transfer agents to be used is remarkably influenced by the activity of the chain transfer agent, the combination of the monomers, the polymerization conditions, and the like, and must be precisely controlled. It is about 01 mol% to 50 mol%, more preferably 0.05 mol% to 30 mol%, still more preferably 0.08 mol% to 25 mol%. These chain transfer agents may be present in the system simultaneously with the target monomer whose degree of polymerization is to be controlled in the polymerization process, and the addition method is not particularly limited. It may be added after being dissolved in the monomer, or may be added separately from the monomer.

  In addition, what has a polymeric group as a substituent in order for the fluorine-type polymer of this invention to fix the orientation state of a discotic liquid crystalline compound is also preferable.

  Specific examples that can be preferably used in the present invention as fluorine-based polymers are shown below, but the present invention is not limited to these specific examples. Here, the numerical values (numerical values such as a, b, c, and d) in the formula are mass percentages indicating the composition ratio of each monomer, and Mw is the mass average molecular weight in terms of PEO measured by GPC.

  The fluoropolymer used in the present invention can be produced by a publicly known and commonly used method. For example, it can be produced by adding a general-purpose radical polymerization initiator to an organic solvent containing the above-mentioned fluorine-based monomer, a monomer having a hydrogen bonding group, and the like, and polymerizing it. Further, in some cases, other addition-polymerizable unsaturated compounds can be further added and produced by the same method as described above. Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition.

  The preferred range of the content of the fluoropolymer in the liquid crystalline composition (liquid crystalline composition excluding the solvent when prepared as a coating liquid) for forming the optically anisotropic layer of the present invention is Although it varies depending on the application, it is preferably 0.005 to 8% by mass, more preferably 0.01 to 5% by mass in the composition (a composition excluding the solvent in the case of a coating solution). 0.05 to 1% by mass is more preferable. If the addition amount of the fluorine-based polymer is less than 0.005% by mass, the effect is insufficient, and if it exceeds 8% by mass, the coating film may not be sufficiently dried or the performance as an optical film (for example, retardation) Adverse effects on the uniformity of

Next, the fluorine-containing compound represented by the formula (III) that can be similarly used as the air interface side vertical alignment agent will be described.
Formula (III)
(R ⁰ ) _mo −L ⁰ − (W) _no
In the formula, R ⁰ represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, and mo represents an integer of 1 or more. A plurality of R ⁰ may be the same or different, but at least one represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal. L ⁰ represents a (mo + no) -valent linking group, W represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or phosphonoxy {—OP (═O) (OH) ₂ } Or a salt thereof, and no represents an integer of 1 or more.

In the formula (III), R ⁰ functions as a hydrophobic group of the fluorine-containing compound. The alkyl group represented by R ⁰ is a substituted or unsubstituted alkyl group, which may be linear or branched, preferably an alkyl group having 1 to 20 carbon atoms, and more preferably Is an alkyl group of 4 to 16, particularly preferably an alkyl group of 6 to 16. As the substituent, any of the substituents exemplified as the substituent group D described later can be applied.

The alkyl group having a CF ₃ group at the terminal represented by R ⁰ preferably has 1 to 20 carbon atoms, more preferably 4 to 16 and even more preferably 4 to 8. The alkyl group having a CF ₃ group at the terminal is an alkyl group in which some or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. 50% or more of hydrogen atoms in the alkyl group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and particularly preferably 70% or more are substituted. The remaining hydrogen atoms may be further substituted with the substituents exemplified as the substituent group D described later. The alkyl group having a CF ₂ H group at the terminal represented by R ⁰ preferably has 1 to 20 carbon atoms, more preferably 4 to 16 and even more preferably 4 to 8. The alkyl group having a CF ₂ H group at the terminal is an alkyl group in which some or all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms. 50% or more of the hydrogen atoms in the alkyl group are preferably substituted with fluorine atoms, more preferably 60% or more are substituted, and even more preferably 70% or more are substituted. The remaining hydrogen atoms may be further substituted with a substituent exemplified as the substituent group D described later. Examples of the alkyl group having a CF ₃ group at the terminal represented by R ⁰ or the alkyl group having a CF ₂ H group at the terminal are shown below.

R1: n-C ₈ F _17-
R2: nC ₆ F _{13-
R3: n-C 4 F 9} -
_{R4: n-C 8 F 17} - (CH 2) 2 -
_{R5: n-C 6 F 13} - (CH 2) 2 -
_{R6: n-C 4 F 9} - (CH 2) 2 -
_{R7: H- (CF 2) 8} -
_{R8: H- (CF 2) 6} -
_{R9: H- (CF 2) 4} -
_{R10: H- (CF 2) 8} - (CH 2) -
R11: H— (CF ₂ ) ₆ — (CH ₂ ) —
R12: H— (CF ₂ ) ₄ — (CH ₂ ) —

In the formula (III), the (mo + no) -valent linking group represented by L ⁰ is an alkylene group, an alkenylene group, an aromatic group, a heterocyclic group, —CO—, —NR ^d — (R ^d is the number of carbon atoms) Is a linking group in which at least two groups selected from the group consisting of —O—, —S—, —SO—, and —SO ₂ — are combined.

In the formula (III), W represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof. . The preferable range of W is the same as Q in the formula (II).

  Among the fluorine-containing compounds represented by the formula (III), compounds represented by the following formula (III) -a or formula (III) -b are preferable.

In formula (III) -a, R ⁴ and R ⁵ each represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, and R ⁴ and R ⁵ are simultaneously It is not an alkyl group. W ¹ and W ² are each a hydrogen atom, a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, phosphonoxy {—OP (═O) (OH) ₂ } or a salt thereof, or An alkyl group, an alkoxy group or an alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent is represented, but W ¹ and W ² are not simultaneously hydrogen atoms.

Formula (III) -b
(R ⁶ -L ^2- ) _m2 (Ar ¹ ) -W ³
In formula (III) -b, R ⁶ represents an alkyl group, an alkyl group having a CF ₃ group at the terminal, or an alkyl group having a CF ₂ H group at the terminal, m2 represents an integer of 1 or more, R ⁶ may be the same or different, but at least one represents an alkyl group having a CF ₃ group or a CF ₂ H group at the terminal. L ² represents an alkylene group, an aromatic group, —CO—, —NR′— (R ′ is an alkyl group having 1 to 5 carbon atoms or a hydrogen atom), —O—, —S—, —SO—, It represents a divalent linking group selected from the group consisting of —SO ₂ — and combinations thereof, and a plurality of L ² may be the same or different. Ar ¹ represents an aromatic hydrocarbon ring or an aromatic heterocycle, W ³ represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof, or an alkyl group, an alkoxy group or an alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent.

First, the formula (III) -a will be described.
R ⁴ and R ⁵ have the same meaning as R ⁰ in formula (III), and the preferred range is also the same. The carboxyl group (—COOH) represented by W ¹ and W ² or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof is It is synonymous with W in Formula (III), and its preferable range is also the same. The alkyl group having a carboxyl group, a sulfo group, or a phosphonoxy group as a substituent represented by W ¹ or W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. It is an alkyl group, More preferably, it is a 1-8 alkyl group, Most preferably, it is a 1-3 alkyl group. The alkyl group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent only needs to have at least one carboxyl group, sulfo group, or phosphonoxy group. It is synonymous with the carboxyl group, sulfo group and phosphonoxy group represented by W in formula (III), and the preferred range is also the same. The alkyl group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent may be substituted with any other substituent, and the substituent is any of the substituents exemplified as the substituent group D described later. Can be applied. The alkoxy group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ¹ or W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. An alkoxy group, more preferably an alkoxy group of 1 to 8, and particularly preferably an alkoxy group of 1 to 4. The alkoxy group having a carboxyl group, a sulfo group, or a phosphonoxy group as the substituent only needs to have at least one carboxyl group, a sulfo group, or a phosphonoxy group. As the carboxyl group, the sulfo group, and the phosphonoxy group, It is synonymous with the carboxyl group, sulfo group and phosphonoxy group represented by W in formula (III), and the preferred range is also the same. The alkoxy group having a carboxyl group, a sulfo group, or a phosphonoxy group may be substituted with other substituents, and any of the substituents exemplified as the substituent group D described later can be applied as the substituent. . The alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group as a substituent represented by W ¹ or W ² may be linear or branched, and preferably has 1 to 20 carbon atoms. More preferably, it is an alkylamino group of 1 to 8, more preferably an alkylamino group of 1 to 4. The alkylamino group having a carboxyl group, a sulfo group, or a phosphonoxy group only needs to have at least one carboxyl group, sulfo group, or phosphonoxy group. It is synonymous with the carboxyl group, sulfo group and phosphonoxy group represented by W in III), and the preferred range is also the same. The alkylamino group having a carboxyl group, a sulfo group, or a phosphonoxy group may be substituted with other substituents, and any of the substituents exemplified as Substituent Group D described later is applied as the substituent. it can.

W ¹ and W ² are particularly preferably each a hydrogen atom or — (CH ₂ ) _n SO ₃ M (n represents 0 or 1). M represents a cation, but M may not be present when the charge is 0 in the molecule. As the cation represented by M, for example, protonium ion, alkali metal ion (lithium ion, sodium ion, potassium ion, etc.), alkaline earth metal ion (barium ion, calcium ion, etc.), ammonium ion, etc. are preferably applied. . Of these, proton ions, lithium ions, sodium ions, potassium ions, and ammonium ions are particularly preferable.

Next, the formula (III) -b will be described.
R ⁶ has the same meaning as R ⁰ in formula (III), and its preferred range is also the same. L ² is preferably an alkylene group having 1 to 12 carbon atoms, an aromatic group having 6 to 12 carbon atoms, —CO—, —NR—, —O—, —S—, —SO—, —SO ₂ — and Represents a linking group having a total carbon number of 0 to 40 consisting of a combination thereof, more preferably an alkylene group having 1 to 8 carbon atoms, a phenyl group, —CO—, —NR—, —O—, —S—, —SO. ₂ represents a linking group having 0 to 20 carbon atoms and a combination thereof. Ar ¹ preferably represents an aromatic hydrocarbon ring having 6 to 12 carbon atoms, more preferably a benzene ring or a naphthalene ring. As a carboxyl group represented by W ³ (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof, or a substituent The alkyl group, alkoxy group, or alkylamino group having a carboxyl group, a sulfo group or a phosphonoxy group is a carboxyl group (—COOH) represented by W ¹ and W ² in the formula (III) -a or a salt thereof, sulfo Group (—SO ₃ H) or a salt thereof, phosphonoxy {—OP (═O) (OH) ₂ } or a salt thereof, or an alkyl group, an alkoxy group, or an alkyl having a carboxyl group, a sulfo group, or a phosphonoxy group as a substituent It is synonymous with an amino group and its preferable range is also the same.

W ³ is preferably a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, or a carboxyl group (—COOH) or a salt thereof or a sulfo group (—SO ₃ H) as a substituent. Alternatively, it is an alkylamino group having a salt thereof, and particularly preferably SO ₃ M or CO ₂ M. M represents a cation, but M may not be present when the charge is 0 in the molecule. As the cation represented by M, for example, protonium ion, alkali metal ion (lithium ion, sodium ion, potassium ion, etc.), alkaline earth metal ion (barium ion, calcium ion, etc.), ammonium ion, etc. are preferably applied. . Of these, proton ions, lithium ions, sodium ions, potassium ions, and ammonium ions are particularly preferable.

  In the present specification, the substituent group D includes an alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as a methyl group. , Ethyl group, isopropyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (preferably having 2 carbon atoms) -20, more preferably an alkenyl group having 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group), alkynyl A group (preferably an alkynyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, still more preferably 2 to 8 carbon atoms, Argyl group, 3-pentynyl group and the like), an aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and further preferably 6 to 12 carbon atoms). Group, p-methylphenyl group, naphthyl group and the like), substituted or unsubstituted amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and further preferably 0 to 6 carbon atoms). An amino group, for example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group and the like),

An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, still more preferably 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group). An aryloxy group (preferably an aryloxy group having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, still more preferably 6 to 12 carbon atoms, and examples thereof include a phenyloxy group and a 2-naphthyloxy group. An acyl group (preferably an acyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms, such as an acetyl group, a benzoyl group, a formyl group, and a pivaloyl group. Etc.), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably A C2-C12 alkoxycarbonyl group, for example, a methoxycarbonyl group, an ethoxycarbonyl group, and the like; an aryloxycarbonyl group (preferably having a carbon number of 7-20, more preferably having a carbon number of 7-16, even more preferably Is an aryloxycarbonyl group having 7 to 10 carbon atoms, such as a phenyloxycarbonyl group, and an acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and still more preferably carbon atoms). An acyloxy group having a number of 2 to 10, and examples thereof include an acetoxy group and a benzoyloxy group).

An acylamino group (preferably an acylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 10 carbon atoms, such as an acetylamino group and a benzoylamino group), alkoxycarbonyl An amino group (preferably an alkoxycarbonylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, still more preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group), aryloxy Carbonylamino group (preferably an aryloxycarbonylamino group having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, still more preferably 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group) A sulfonylamino group (preferably having 1 to 20 carbon atoms) Preferably it is a C1-C16, More preferably, it is a C1-C12 sulfonylamino group, for example, a methanesulfonylamino group, a benzenesulfonylamino group, etc.), a sulfamoyl group (preferably C0-20). More preferably, it is a sulfamoyl group having 0 to 16 carbon atoms, more preferably 0 to 12 carbon atoms, and examples thereof include a sulfamoyl group, a methylsulfamoyl group, a dimethylsulfamoyl group, and a phenylsulfamoyl group. ), A carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms, such as an unsubstituted carbamoyl group, a methylcarbamoyl group, or a diethylcarbamoyl group. Group, phenylcarbamoyl group, etc.),

An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is a C6-C20, More preferably, it is a C6-C16, More preferably, it is a C6-C12 arylthio group, For example, a phenylthio group etc. are mentioned, A sulfonyl group (preferably C1-C1). 20, more preferably a sulfonyl group having 1 to 16 carbon atoms, still more preferably 1 to 12 carbon atoms, and examples thereof include a mesyl group and a tosyl group), a sulfinyl group (preferably having a carbon number of 1 to 20, and more. A sulfinyl group having 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, is preferable. A ureido group (preferably a benzenesulfinyl group), a ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms. Ureido group, methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, and further preferably having 1 to 12 carbon atoms) Group such as diethyl phosphoramide group and phenylphosphoric acid amide group), hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group Group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably A heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, such as a heterocyclic group having a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom, such as an imidazolyl group, a pyridyl group, or a quinolyl group; Group, furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, More preferably, it is a silyl group having 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group. These substituents may be further substituted with these substituents. Further, when two or more substituents are present, they may be the same or different. If possible, they may be bonded to each other to form a ring.

  The fluorine-containing compound of the present invention preferably has a polymerizable group as a substituent in order to fix the alignment state of the discotic liquid crystalline compound.

  Specific examples of the fluorine-containing compound represented by the formula (III) that can be used in the present invention are shown below, but the fluorine-containing compound used in the present invention is not limited thereto.

The preferable range of the content of the fluorine-containing compound in the liquid crystal composition varies depending on the use, but 0.005 to 0.005 in the liquid crystal composition (a composition excluding the solvent in the case of a coating liquid). The content is preferably 8% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.05 to 1% by mass.
Each of the first optical anisotropic layer and the second optical anisotropy preferably contains the fluorine-containing compound, and more preferably contains one or more kinds of the same fluorine-containing compound. In particular, when the same fluorine-based compound is employed, when the first optical anisotropic layer and the second optical anisotropic layer are laminated, the adhesion between the two layers is improved, which is preferable.

[Coating solvent]
As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg N, N-dimethylformamide), sulfoxides (eg dimethyl sulfoxide), heterocyclic compounds (eg pyridine), hydrocarbons (eg benzene, hexane), alkyl halides (eg , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. Application | coating of a coating liquid can be implemented by a well-known method (For example, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

[Polymerization initiator]
The vertically aligned liquid crystal compound is fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of the polymerizable group (P) introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970).

It is preferable that the usage-amount of a photoinitiator is 0.01-20 mass% of solid content of a coating liquid, and it is more preferable that it is 0.5-5 mass%. The light irradiation for the polymerization of the discotic liquid crystalline compound preferably uses ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the retardation layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 1 to 5 μm.

[Other additives for optically anisotropic layer]
Along with the liquid crystal compound, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal compound, and the like. These materials are preferably compatible with the liquid crystal compound and do not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the polymerizable group-containing liquid crystalline compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is preferably 1 to 50% by mass and more preferably 5 to 30% by mass with respect to the discotic liquid crystalline compound.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specifically, for example, compounds described in paragraph Nos. [0028] to [0056] in JP 2001-330725 A, paragraph Nos. [0069] to [0126] in JP 2003-295212 A, and the like. And the compounds described in the above.

The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass and in the range of 0.1 to 8% by mass with respect to the liquid crystal compound so as not to inhibit the alignment of the liquid crystal compound. It is more preferable.
The discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystal compound is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

[Alignment film]
In the present invention, the liquid crystalline composition may be applied to the surface of the alignment film to align the molecules of the liquid crystalline compound. Since the alignment film has a function of defining the alignment direction of the liquid crystalline compound, it is preferably used for realizing a preferred embodiment of the present invention. However, if the alignment state is fixed after aligning the liquid crystalline compound, the alignment film plays a role, and is not necessarily essential as a component of the present invention. That is, it is possible to produce the polarizing plate of the present invention by transferring only the optically anisotropic layer on the alignment film in which the alignment state is fixed onto the polarizer.
The alignment film may be an organic compound (for example, ω-tricosanoic acid) by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.
The alignment film is preferably formed by polymer rubbing treatment.

  Examples of the polymer include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylolacrylamide) described in paragraph [0022] of JP-A-8-338913, for example. ), Polyester, polyimide, vinyl acetate copolymer, carboxymethyl cellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (for example, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol) are preferable, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferable, and polyvinyl alcohol and modified polyvinyl alcohol are most preferable. .

  70-100% is preferable and, as for the saponification degree of polyvinyl alcohol, 80-100% is more preferable. The polymerization degree of polyvinyl alcohol is preferably 100 to 5000.

In the alignment film of the present invention, a side chain having a crosslinkable functional group (for example, a double bond) is bonded to the main chain, or a crosslinkable functional group having a function of aligning a liquid crystal compound is introduced into the side chain. It is preferable to do. As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used.
When the side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer or the crosslinkable functional group is introduced into the side chain having the function of aligning the liquid crystalline compound, the alignment film polymer and the optically anisotropic film The polyfunctional monomer contained in the conductive layer can be copolymerized. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer is firmly bonded by a covalent bond. Therefore, the strength of the optical compensation sheet can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.
The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] of JP-A No. 2000-155216.

  Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] of JP-A No. 2002-62426. Aldehydes having high reaction activity are preferred, and glutaraldehyde is more preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high-temperature and high-humidity atmosphere for a long time, sufficient durability without generation of reticulation can be obtained.

  The alignment film can be formed by, for example, applying a solution containing the polymer, the crosslinking agent, and the additive, which is an alignment film forming material, onto a transparent support, followed by heat drying (crosslinking) and rubbing treatment. it can. As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating liquid is preferably a mixed solvent of an organic solvent (for example, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an alignment film and also an optically anisotropic layer reduces remarkably.

  As a method for applying the alignment film, a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method or a roll coating method is preferable, and a rod coating method is more preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 130 ° C. In order to form sufficient crosslinks, 40 ° C to 120 ° C is preferable, and 50 ° C to 110 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is also preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, pH 4.5 to 5.5 is preferable, and 5 is more preferable.

  The alignment film is preferably provided on the transparent support. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above.

  For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

The liquid crystalline composition is applied to the rubbing-treated surface of the alignment film to align the molecules of the liquid crystalline compound. Thereafter, if necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer are reacted, or the alignment film polymer is crosslinked using a crosslinking agent, thereby the optically anisotropic layer. Can be formed.
The thickness of the alignment film is preferably in the range of 0.1 to 10 μm.
Moreover, when a 2nd optically anisotropic layer is laminated | stacked on a 1st optically anisotropic layer, the aspect which does not provide an orientation film substantially between the said 2 layers is also preferable. The phrase “substantially no alignment film” means that a film formed only for functioning as an alignment film is not included. Even if the surface of the first optically anisotropic layer contributes to the alignment of the liquid crystalline compound of the second optically anisotropic layer, the first optically anisotropic layer is only used as an alignment film. As long as it is not formed for use, it is included in the “substantially no alignment film” regardless of the presence or absence of rubbing.

{Cellulose acylate film}
Next, the cellulose acylate film preferably used in the present invention will be described.
The cellulose acylate film preferably used in the present invention is formed using a specific cellulose acylate as a raw material. Different cellulose acylates are used depending on whether the optical anisotropy is increased or decreased.

[Cellulose acylate for increasing optical anisotropy]
First, the cellulose acylate for increasing the optical anisotropy 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 specific cellulose acylate is a mixed fatty acid ester of cellulose obtained by substituting the 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 as follows: It is preferable that the cellulose acylate satisfies the mathematical formulas (4) and (5).
Formula (4): 2.0 ≦ A + B ≦ 3.0
Formula (5): 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 degree of substitution of 1).

  In the present invention, the total substitution degree (A + B) of hydroxyl groups A and B is preferably 2.0 to 3.0, more preferably 2.2 to as shown in the above formula (4). 2.9, particularly preferably 2.40 to 2.85. Further, the substitution degree of B is preferably larger than 0, and more preferably 0.6 or more, as shown in the above formula (5). If (A + B) is 2.0 or more, it is preferable because the hydrophilicity becomes too strong and inconveniences such as being easily affected by environmental humidity do not occur.

  Further, in the above formula (5), 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, and more preferably 31% or more. In particular, it is preferable that at least 32% of the substituents are a hydroxyl group at the 6-position.

  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 with an acyl group is DS ₂ , and the acyl of the hydroxyl group at the 3-position When the degree of substitution with a group is DS ₃ and the degree of substitution with an acyl group of the hydroxyl group at the 6-position is DS ₆ , it is preferable that the following mathematical formulas (6) and (7) are satisfied.
Formula (6): 2.0 ≦ DS ₂ + DS ₃ + DS ₆ ≦ 3.0
Formula (7): DS ₆ / (DS ₂ + DS ₃ + DS ₆ ) ≧ 0.315
Satisfying the above formulas (6) and (7) is preferable because the solubility of the cellulose acylate film in the solvent is improved and the humidity dependence of the optical anisotropy is reduced.
Further, the acyl group is preferably an acetyl group in that saponification is likely to proceed, the elastic modulus is high, the dimensional change is small, the durability is high, and the cost is low.

  The acyl group having 3 or more carbon atoms may be an aliphatic group or an aromatic hydrocarbon group, and is not particularly limited. They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters or aromatic carbonyl esters of cellulose, aromatic alkyl carbonyl esters and the like, and each may have a further substituted group.

Preferred examples of the acyl group having 3 or more carbon atoms include propionyl, butanoyl, keptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, i-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.

[Cellulose acylate for reducing optical anisotropy]
When reducing the optical anisotropy, it is desirable that the acyl substitution degree of the cellulose hydroxyl group is 2.50 to 3.00. Furthermore, the substitution degree is desirably 2.75 to 3.00, and more desirably 2.85 to 3.00.

  Among the acyl groups having 2 to 22 carbon atoms substituted for the hydroxyl group of cellulose, the acyl group having 2 to 22 carbon atoms may be an aliphatic group or an aryl group, and is not particularly limited. It may be a mixture. They are, for example, alkyl carbonyl esters, alkenyl carbonyl esters or aromatic carbonyl esters of cellulose, aromatic alkyl carbonyl esters and the like, and each may have a further substituted group.

  These preferred acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, iso-butanoyl, t-butanoyl, cyclohexanecarbonyl, Examples include oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl groups. Among these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like are preferable, and acetyl, propionyl and butanoyl are more preferable.

  Among the acyl substituents substituted on the hydroxyl group of cellulose described above, when it is substantially composed of at least two of an acetyl group, a propionyl group, and a butanoyl group, the total degree of substitution may be 2.50 to 3.00. preferable. A more preferable degree of acyl substitution is 2.75 to 3.00, and more desirably 2.85 to 3.00. If it exists in said range, the optical anisotropy of a cellulose acylate film can fully be reduced, and it is preferable.

[Method of synthesizing cellulose acylate]
The basic principle of the cellulose acylate synthesis method is described in Mita et al., Wood Chemistry pages 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 substitution 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 by using 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, the polymer component constituting the film is preferably substantially composed of the specific cellulose acylate.
Here, “substantially” means 55 mass% or more (preferably 70 mass% or more, more preferably 80 mass% or more) of the polymer component.

  The cellulose acylate is preferably used in the form of particles. It is preferable that 90% by mass or more of the particles to be used 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 the 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 Uda et al.'S intrinsic viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Society, Vol. 18, No. 1, pages 105-120, 1962). 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 cellulose acylate is used for production of a film, 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 this invention, in order to make the moisture content of a cellulose acylate into the said suitable range, it is necessary to dry, and the method will not be specifically limited if it is a method used as the target moisture content.

  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 preferably used in the present invention can be obtained by forming a film using a solution prepared 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, a wavelength dispersion adjusting agent, a dye, 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-2001-151901.

[Ultraviolet absorber]
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′-t-butylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5 Examples include chlorobenzotriazole, 2 (2′-hydroxy-5′-t-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′-t-butyl- 5'-methylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-t-amylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-t-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. The ultraviolet absorbent for liquid crystal is preferably one that is excellent in the ability to absorb ultraviolet light having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of the liquid crystal and that has little absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. 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 0.001% by mass or more, the effect of addition can be sufficiently exerted, and if the addition amount is 5% by mass or less, it is preferable because bleeding out of the ultraviolet absorber to the film surface can be suppressed.

  Further, the ultraviolet absorber may be added simultaneously with 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 spectral absorption characteristics can be easily adjusted.

[Deterioration inhibitor]
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).

[Plasticizer]
The plasticizer is preferably a phosphate ester or a carboxylic acid ester. Examples of the phosphate ester plasticizer include triphenyl phosphate (TPP), tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate (BDP), trioctyl phosphate, tributyl phosphate and the like; Examples of the acid ester plasticizer include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP), diethyl hexyl phthalate (DEHP), O-acetyl citrate. Triethyl acid (OACTE), O-acetyl tributyl citrate (OACTB), acetyl triethyl citrate, acetyl tributyl citrate, oleic acid , Methyl ricinoleate, dibutyl sebacate, triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, etc. The plasticizer used in the invention is more preferably selected from these exemplified plasticizers. Furthermore, the plasticizer is preferably (di) pentaerythritol esters, glycerol esters, diglycerol esters.

[Peeling accelerator]
Examples of the peeling accelerator include citric acid ethyl esters.
[Infrared absorber]
Furthermore, as an infrared absorber, it describes in Unexamined-Japanese-Patent No. 2001-194522, for example.

[Additional time]
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 the additive 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, although described in Japanese Patent Application Laid-Open No. 2001-151902, these are conventionally known techniques.

  The glass transition point Tg measured by a dynamic viscoelasticity measuring device “Vibron: DVA-225” {manufactured by IT Measurement Control Co., Ltd.)} of a cellulose acylate film is selected by selecting the type and amount of these additives. It is preferable that the elastic modulus measured by a tensile tester “Strograph-R2” {manufactured by Toyo Seiki Seisakusho} is 1500 to 4000 MPa at ˜150 ° C. More preferably, the glass transition point Tg is 80 to 135 ° C. and the elastic modulus is 1500 to 3000 MPa. That is, the cellulose acylate film preferably used in the present invention preferably has a glass transition point Tg and an elastic modulus within the above ranges from the viewpoint of process suitability for polarizing plate processing and liquid crystal display device assembly.

  Furthermore, about additive, the said public technical number 2001-1745 p. Those described in detail after 16 can be used as appropriate.

[Retardation expression agent]
In the present invention, when the optical anisotropy is greatly expressed, it is preferable to use a retardation developer in order to 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 enhancer composed of the rod-shaped 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 disk-shaped retardation developer is preferably used in a range of 0.05 to 20 parts by mass, and in a range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the polymer component containing the cellulose acylate. It is more preferable to use it, it is more preferable to use in the range of 0.2-5 mass parts, and it is most preferable to use in the range of 0.5-2 mass parts.

Since the discotic compound is superior to the rod-shaped compound in Rth retardation expression, it is preferably used when particularly large Rth retardation is required.
Two or more retardation developers 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.

(Discotic compound)
Hereinafter, 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 bonding relationship between two aromatic rings can be classified into (a) when forming a condensed ring, (b) when directly connecting with a single bond, and (c) when connecting via 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 thiantole Ring is included. 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 by 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.
c ₁ : —CO—O—
c _2: -CO-NH-
c _3: - alkylene -O-
c _4: -NH-CO-NH-
c _5: -NH-CO-O-
c _6: -O-CO-O-
c _7: -O- alkylene -O-
c _8: -CO- alkenylene -
c _9: -CO- alkenylene -NH-
c _10: -CO- alkenylene -O-
c _11: - alkylene -CO-O- alkylene -O-CO- alkylene -
c _12: -O- alkylene -CO-O- alkylene -O-CO- alkylene -O-
c _13: -O-CO- alkylene -CO-O-
c _14: -NH-CO- alkenylene -
c _15: -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.

  It is preferable that the alkyl group 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 (for example, a hydroxy group, a carboxy group, an alkoxy group, an 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-methoxyethyl. 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 alkoxy group preferably has 1 to 8 carbon atoms. The alkoxy group may further have a substituent (for example, an 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 alkoxycarbonylamino group preferably has 2 to 10 carbon atoms. 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 aliphatic substituted amino group preferably has 1 to 10 carbon atoms. 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 aliphatic substituted ureido group preferably has 2 to 10 carbon atoms. 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.

(Bar compound)
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 is performed using molecular orbital calculation software {for example, “WinMOPAC2000” manufactured by Fujitsu Limited}, and a molecular structure that minimizes the heat of formation of a compound can be obtained. The linear molecular structure means that in the thermodynamically most stable structure obtained by calculation as described above, the angle formed by the main chain in the molecular structure is 140 ° 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 (for example, methyl Amino group, ethylamino group, butylamino group, dimethylamino group), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (for example, N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N-dimethylcarbamoyl group) ), Sulfamoyl group, alkylsulfamoyl group (for example, N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group), ureido group, alkylureido group (for example, N -Methylureido group, N, N-dimethylureido group, N, N, N'-trimethylureido group), a Alkyl group (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, heptyl group, octyl group, isopropyl group, s-butyl group, t-amyl group, cyclohexyl group, cyclopentyl group), alkenyl group (for example, , Vinyl group, allyl group, hexenyl group), alkynyl group (for example, ethynyl group, butynyl group), acyl group (for example, formyl group, acetyl group, butyryl group, hexanoyl group, lauryl group), acyloxy group (for example, acetoxy group) Group, butyryloxy group, hexanoyloxy group, lauryloxy group), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, heptyloxy group, octyloxy group), aryloxy group (for example, , Phenoxy group), alkoxycarbonyl group (for example, Methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, heptyloxycarbonyl group), aryloxycarbonyl group (for example, phenoxycarbonyl group), alkoxycarbonylamino group (for example, butoxycarbonylamino group) Hexyloxycarbonylamino group), alkylthio group (for example, methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group, octylthio group), arylthio group (for example, phenylthio group), alkylsulfonyl group (for example, Methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, butylsulfonyl group, pentylsulfonyl group, heptylsulfonyl group, octylsulfonyl group) Amide group (e.g., acetamido group, butylamide group, hexylamide group, laurylamide group) and a non-aromatic Hajime Tamaki (e.g., morpholyl group, pyrazinyl group) include.

  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 moiety of the alkylamino group, alkoxycarbonyl group, alkoxy group, and alkylthio group and the alkyl group may further have a substituent. Examples of alkyl moieties and substituents of alkyl groups include halogen atoms, hydroxyl, carboxyl, cyano, amino, alkylamino groups, nitro, sulfo, carbamoyl, alkylcarbamoyl groups, sulfamoyl, alkylsulfamoyl groups, 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 number of carbon atoms of the alkylene group is preferably 1-20, more preferably 1-15, still more preferably 1-10, still more preferably 1-8, and most preferably 1-6. It is.

  The alkenylene group and the 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 alkenylene group and the alkynylene group preferably have 2 to 10 carbon atoms, more preferably 2 to 8, more preferably 2 to 6, still more 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 140 ° or more.

As the rod-like compound, a compound represented by the following general formula (2) is more preferable.
Formula ^{(2): Ar 1 -L 2} -X-L 3 -Ar 2
In the general formula (2), Ar ¹ and Ar ² are each independently an aromatic group.

The definition and examples of the aromatic group are the same as those of Ar ¹ and Ar ^{2 in} the general formula (1). L ² and L ³ are each independently a divalent linking group selected from an alkylene group, —O—, —CO— and a group consisting of a combination thereof.
The alkylene group preferably has a chain structure rather than a cyclic structure, and more preferably has a linear structure rather than a branched chain structure. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, and 1 or 2 (methylene or ethylene). ) Is most preferred.
L ² and L ³ are particularly preferably —O—CO— or —CO—O—.

  In the general formula (2), X is 1,4-cyclohexylene, vinylene or ethynylene.

  Specific examples of the compound represented by the general formula (1) or (2) include compounds described in [Chemical Formula 1] to [Chemical Formula 11] of JP-A No. 2004-109657.

In addition, a compound represented by the following general formula (3) is also preferable.
General formula (3):

(In the formula, 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 R ¹ , R ² , R ³ , at least one of R ⁴ and R ⁵ represents an electron donating group, and R ⁸ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkyl group having 2 to 6 carbon atoms. An alkynyl group, 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, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, Represents a cyano group or a halogen atom.)

  Among the retardation enhancers, specific examples of the rod-shaped compound represented by the general formula (3) are shown below.

In the ultraviolet absorption spectrum of the solution, two or more rod-shaped compounds having a maximum absorption wavelength (λ _max ) shorter than 250 nm may be used in combination.

The rod-like compound can be synthesized by a method described in the literature.
The literature includes “Mol. Cryst. Liq. Cryst.”, 53, p229 (1979), 89, p93 (1982), 145, p111 (1987), 170, p43 ( 1989), “J. Am. Chem. Soc.”, 113, p1349 (1991), 118, p5346 (1996), 92, p1582 (1970), “J. Org. Chem. ", 40, p420 (1975)," Tetrahedron ", 48, 16, p3437 (1992).

[Retardation reducing agent]
The retardation reducing agent used for reducing the optical anisotropy of the cellulose acylate film will be described.
Using a compound that suppresses the orientation of cellulose acylate in the film in the plane and in the film thickness direction, the optical anisotropy is sufficiently reduced, and Re and Rth can be made zero or close to zero. it can. For this purpose, it is advantageous that the compound that lowers the optical anisotropy is sufficiently compatible with cellulose acylate, and the compound itself does not have a rod-like structure or a planar structure. Specifically, when a plurality of planar functional groups such as aromatic groups are provided, a structure having these functional groups in a non-planar rather than the same plane is advantageous.

(Log P value)
In producing a cellulose acylate film having a low optical anisotropy, as described above, the cellulose acylate in the film is suppressed from being oriented in the plane and in the film thickness direction, thereby reducing the optical anisotropy. Of the compounds, compounds having an octanol-water partition coefficient (log P value) of 0 to 7 are preferred. If the logP value of the compound is 7 or less, the compatibility with the cellulose acylate is good, and problems such as white turbidity and powder blowing of the film are less likely to occur.
Moreover, if the logP value of the compound is 0 or more, the hydrophilicity does not become too high and the water resistance of the cellulose acylate film is not deteriorated, which is preferable. A more preferable range for the logP value is 1 to 6, and a particularly preferable range is 1.5 to 5.

  The octanol-water partition coefficient (log P value) can be measured by a flask soaking method described in JIS Z-7260-107 (2000). Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of the actual measurement.

  As a calculation method, Crippen's fragmentation method {"J. Chem. Inf. Comput. Sci.", 27, p21 (1987)}, Viswanadhan's fragmentation method {"J. Chem. Inf. Comput. Sci." ., 29, p163 (1989)}, Broto's fragmentation method {“Eur. J. Med. Chem.-Chim. Theor.”, 19, p71 (1984)}, etc. are preferably used. , Crippen's fragmentation method {"J. Chem. Inf. Comput. Sci.", 27, p21 (1987)}.

  When the log P value of a certain compound varies depending on the measurement method or calculation method, it is preferable to determine whether or not the compound is within the above range by the Crippen's fragmentation method.

(Physical properties of compounds that reduce optical anisotropy)
The compound that reduces optical anisotropy may or may not contain an aromatic group. The compound that reduces the optical anisotropy preferably has a molecular weight of 150 or more and 3000 or less, preferably 170 or more and 2000 or less, and particularly preferably 200 or more and 1000 or less. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or polymer structure in which a plurality of the monomer units are bonded may be used.

  The compound that reduces optical anisotropy is preferably liquid at 25 ° C. or a solid having a melting point of 25 to 250 ° C., more preferably liquid at 25 ° C. or a melting point of 25 to 200 ° C. It is a solid. Moreover, it is preferable that the compound which reduces optical anisotropy does not volatilize in the process of dope casting for cellulose acylate film production and drying.

  The addition amount of the compound that decreases the optical anisotropy is preferably 0.01 to 30% by mass of the cellulose acylate, more preferably 1 to 25% by mass, and 5 to 20% by mass. Is particularly preferred.

  The compound that decreases the optical anisotropy may be used alone, or two or more compounds may be mixed and used in an arbitrary ratio.

  The timing for adding the compound that decreases the optical anisotropy may be any time during the dope preparation process, or may be performed at the end of the dope preparation process.

  The compound that reduces the optical anisotropy is such that the average content of the compound in the portion from the surface on at least one side to 10% of the total film thickness is the average content of the compound in the central portion of the cellulose acylate film. It is preferable that it is 80 to 99% of. The amount of the compound that reduces the optical anisotropy can be determined by measuring the amount of the compound at the surface and in the central portion, for example, by a method using an infrared absorption spectrum described in JP-A-8-57879. .

(Specific examples of compounds that reduce optical anisotropy)
Although the specific example of the compound which reduces the optical anisotropy of the cellulose acylate film preferably used by this invention below is shown, this invention is not limited to these compounds.

[Wavelength dispersion adjusting agent]
Next, compounds that reduce the wavelength dispersion of the cellulose acylate film will be described. At least one compound having absorption in the ultraviolet region of 200 to ₄₀₀ nm and lowering | Re ₄₀₀ -Re ₇₀₀ | and | Rth ₄₀₀ -Rth ₇₀₀ | of the film, 0.01 to 30 relative to the solid content of cellulose acylate It is preferable to contain the mass%. By containing the wavelength dispersion adjusting agent, the wavelength dispersion of Re and Rth of the cellulose acylate film can be adjusted. Here, Re ₄₀₀ and Rth ₄₀₀ represent values at a wavelength λ = 400 nm, and Re ₇₀₀ and Rth ₇₀₀ represent values at a wavelength λ = 700 nm (both units: nm). As the addition amount of such a compound, the wavelength dispersion of Re and Rth of the cellulose acylate film can be adjusted by including 0.1 to 30% by mass.

  In general, the Re and Rth values of the cellulose acylate film have a wavelength dispersion characteristic that the longer wavelength side is larger than the shorter wavelength side. Therefore, it is required to smoothen the chromatic dispersion by increasing Re and Rth on the relatively small short wavelength side. On the other hand, a compound having absorption in the ultraviolet region of 200 to 400 nm has a wavelength dispersion characteristic in which the absorbance on the long wavelength side is larger than that on the short wavelength side. If this compound itself is isotropically present inside the cellulose acylate film, it is assumed that the birefringence of the compound itself, and thus the wavelength dispersion of Re and Rth, is large on the short wavelength side as well as the wavelength dispersion of absorbance. The

  Therefore, by using the above-described compound having absorption in the ultraviolet region of 200 to 400 nm and having a wavelength dispersion of Re and Rth of the compound itself large on the short wavelength side, Re of the cellulose acylate film, Rth wavelength dispersion can be prepared. For this purpose, the compound for adjusting the wavelength dispersion is required to be sufficiently uniformly compatible with the cellulose acylate. The absorption band range in the ultraviolet region of such a compound is preferably 200 to 400 nm, more preferably 220 to 395 nm, and even more preferably 240 to 390 nm.

In recent years, liquid crystal display devices such as televisions, notebook computers, and mobile portable terminals have been required to have excellent transmittance of optical members used in the liquid crystal display device in order to increase luminance with less power. In that respect, when a compound having absorption in the ultraviolet region of 200 to ₄₀₀ nm and reducing | Re ₄₀₀ -Re ₇₀₀ | and | Rth ₄₀₀ -Rth ₇₀₀ | of the film is added to the cellulose acylate film, spectral transmission is achieved. The rate is required to be excellent. In the cellulose acylate film preferably used in the present invention, the spectral transmittance at a wavelength of 380 nm is preferably 45% or more and 95% or less, and the spectral transmittance at a wavelength of 350 nm is preferably 10% or less.

  As described above, the wavelength dispersion adjusting agent preferably used in the present invention preferably has a molecular weight of 250 to 1000 from the viewpoint of volatility. More preferably, it is 260-800, More preferably, it is 270-800, Most preferably, it is 300-800. A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.

  It is preferable that the wavelength dispersion adjusting agent does not volatilize during the dope casting and drying process for producing the cellulose acylate film.

(Addition amount of wavelength dispersion adjusting agent)
The addition amount of the wavelength dispersion adjusting agent preferably used in the present invention is preferably 0.01 to 30% by mass, and preferably 0.1 to 20% by mass with respect to the solid content of cellulose acylate. More preferably, it is especially preferable that it is 0.2-10 mass%.

(Method of adding wavelength dispersion adjusting agent)
These wavelength dispersion adjusting agents may be used alone or in combination of two or more compounds at an arbitrary ratio.
Further, the timing of adding these wavelength dispersion adjusting agents may be any time during the dope preparation process, or may be performed at the end of the dope preparation process.

  Specific examples of the wavelength dispersion adjusting agent preferably used in the present invention include, for example, benzotriazole compounds, benzophenone compounds, compounds containing a cyano group, oxybenzophenone compounds, salicylic acid ester compounds, nickel complex compounds, and the like. However, the present invention is not limited only to these compounds.

[dye]
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 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 dyes described in JP-A-5-34858 can be used.

[Matting agent fine particles]
It is preferable to add fine particles as a matting agent to the cellulose acylate film preferably used in 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, magnesium silicate and Mention may be made of calcium phosphate. As the fine particles, those 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 / L 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 / L or more, and more preferably 100 to 200 g / L or more. A higher apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are improved.

  When silicon dioxide fine particles are used as the matting agent, the amount 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, but are present as aggregates of primary particles in the film, and 0.1 to 3.0 μm on the film surface. Form irregularities. The average particle diameter of the secondary particles 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. If the average particle diameter is 1.5 μm or less, the haze will not be too strong, and if it is 0.2 μm or more, the effect of preventing squeezing will be sufficiently exhibited, which is preferable.

  The primary and secondary particle diameters of the fine particles 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 the fine particles of silicon dioxide, for example, commercially available products such as “Aerosil” R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 {above, manufactured by Nippon Aerosil Co., Ltd.} can be used. . Zirconium oxide fine particles are commercially available under the trade names of “Aerosil” R976 and R811 {above, 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 / L or more, and low turbidity of the optical film. This is particularly preferable because the effect of reducing the coefficient of friction is large while maintaining it.

In the present invention, in order to obtain a cellulose acylate film containing particles having a small secondary average particle size, several methods are conceivable when preparing a dispersion of fine particles. For example, a fine particle dispersion prepared by stirring and mixing a solvent and fine particles is prepared in advance, and this fine particle dispersion is added to a small amount of a separately prepared cellulose acylate solution, dissolved by stirring, and further mixed with the main cellulose acylate dope solution. There is a way. This method is a preferred 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 in-line mixer. There is also a way to do it. In the present invention, although not limited to these methods, 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, and 10 to 25% by mass. Is more preferable, and 15 to 20% by mass is most preferable.
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 formation of a cellulose ester.

  Next, the organic solvent in which cellulose acylate preferably used in the present invention is dissolved will be described.

  In the present invention, as the organic solvent, 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.

[Chlorine solvent]
In preparing the cellulose acylate solution preferably used in 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 as long as the cellulose acylate is dissolved and can be cast and formed into a film. 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 preferable 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 and hydrocarbons having 3 to 12 carbon atoms is preferable. The ester, ketone, ether and alcohol 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 compounds such as alcoholic hydroxyl groups can be used. You may have a functional 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 the 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 preferably 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.

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 (parts 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).

[Non-chlorine solvents]
Next, a non-chlorine organic solvent that is preferably used in preparing a cellulose acylate solution that is preferably used in 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 is dissolved and can be cast and formed into a film. The non-chlorine organic solvent used in the present invention is preferably a solvent having 3 to 12 carbon atoms and selected from esters, ketones and ethers. 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. 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, methylcyclohexanone and methyl acetyl acetate. 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 above-mentioned non-chlorine organic solvent used for 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, wherein 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 not be provided. 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 mixture thereof. It may be a solvent.

  The alcohol as the third solvent may have a hydrocarbon chain that is linear, branched, or cyclic, and among them, a saturated aliphatic hydrocarbon chain 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. In addition, as the alcohol, a fluorine-based alcohol in which part or all of the hydrogen in the hydrocarbon chain is substituted with fluorine 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 a mixture 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, and hydrocarbons such as cyclohexane and hexane. Particularly preferred are methanol, ethanol, 1-propanol, 2-propanol and 1-butanol.

  The mixing ratio of the above three types of mixed solvents is that the first solvent is 20 to 95% by mass, the second solvent is 2 to 60% by mass, and the third solvent is 2 to 30% by mass in the total amount of the mixed solvent. %, Preferably the first solvent is 30 to 90% by mass, the second solvent is 3 to 50% by mass, and the third alcohol is 3 to 25% by mass. preferable. In particular, the first solvent is preferably 30 to 90% by mass, the second solvent is preferably 3 to 30% by mass, and the third solvent is an alcohol, and preferably 3 to 15% by mass.

  The non-chlorine-based organic solvent used in the present invention described above is more specifically described in the above-mentioned Japanese Patent No. 2001-1745 p. 12-16.

Preferred combinations of non-chlorine organic solvents of the present invention can be listed below, 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 (parts 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.

Furthermore, 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 mass of butanol after filtration and concentration,
A method of preparing a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol = 84/10/4/2 (parts by mass), adding 4 parts by mass of butanol after filtration and concentration,
A method of preparing a cellulose acylate solution with methyl acetate / acetone / ethanol = 84/10/6 (parts by mass), and adding 5 parts by mass of butanol after filtration and concentration.

  In addition to the non-chlorine organic solvent of the present invention, the dope used in the present invention may contain dichloromethane in an amount of 10% by mass or less based on the total amount of the organic solvent of the present invention.

[Characteristics of cellulose acylate solution]
The cellulose acylate solution is a solution in which cellulose acylate is dissolved in the organic solvent, and the concentration thereof is preferably in the range of 10 to 30% by mass from the viewpoint of film-forming casting suitability, more preferably. It is 13-27 mass%, Most preferably, it is 15-25 mass%.
A method for bringing the cellulose acylate solution into such a concentration range may be a predetermined concentration at the stage of dissolution, and will be described later after it is prepared in advance as a low concentration solution (for example, 9 to 14% by mass). You may adjust to a predetermined high concentration solution by a concentration process. Furthermore, after preparing a high concentration cellulose acylate solution in advance, various additives may be added to obtain a predetermined low concentration cellulose acylate solution, and any method is preferably used in the present invention. There is no particular problem if it is carried out so as to have a concentration.

Next, in the present invention, when the cellulose acylate solution is made 0.1 to 5% by mass with an organic solvent having the same composition, the aggregate molecular weight of the cellulose acylate in the diluted solution is 150,000 to 15 million. Is preferable from the viewpoint of solubility in a solvent. The associated molecular weight is more preferably 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 melt | dissolve so that the inertial radius calculated | required simultaneously may be 10-200 nm. A more preferable radius of inertia 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 associated molecular weight, the radius of inertia, 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 solutions of 0.1 mass%, 0.2 mass%, 0.3 mass%, and 0.4 mass%. 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, the solution and the solvent are filtered through a 0.2 μm Teflon (registered trademark) filter. Then, static light scattering of the filtered solution is measured at 10 ° intervals 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. The refractive index necessary for this analysis is the value of the solvent determined by the Abbe refractive system, and the refractive index concentration gradient (dn / dc) is a differential refractometer “DRM-1021” {manufactured by Otsuka Electronics Co., Ltd. }, And using the solvent and solution used for the light scattering measurement.

[Preparation of dope]
Next, preparation of a solution (dope) for casting and film formation of cellulose acylate will be described.
The method for dissolving cellulose acylate is not particularly limited, and may be a room temperature dissolution method, a cooling dissolution method or a high temperature dissolution method, or 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-A-2000-273184, JP-A-11-323017, JP-A-11-302388, and the like describe the methods for preparing a cellulose acylate solution.

  The above-described method for dissolving cellulose acylate in an organic solvent can be applied to the present invention even within the scope of the present invention. For details of these, especially non-chlorine solvent systems, see the above-mentioned technical number 2001-1745 p. 22-25, which can be carried out according to that method. Further, the cellulose acylate dope solution preferably used in the present invention is usually subjected to solution concentration and filtration. 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 carries out 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. These values are measured using 1 mL of the sample solution in a rheometer “CLS 500” and “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. Note that 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. Therefore, the dynamic storage elastic modulus at 15 ° C. should be 100 to 1,000,000. Furthermore, the dynamic storage elastic modulus at low temperature is preferably as large as possible. 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 support 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 can be obtained. A cellulose acylate having a high concentration and excellent stability can be obtained without resorting to a means of concentration. A rate solution is obtained. Further, in order to facilitate dissolution, it may be concentrated using a concentration means after being dissolved at a low concentration. 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 giving a difference and obtaining a high-concentration solution while evaporating the solvent (for example, JP-A-4-259511), until a heated low-concentration solution is blown into the container from the nozzle until the solution hits the inner wall of the container from the nozzle The solvent is flash evaporated between the container and the solvent vapor is withdrawn from the container and the concentrated solution is withdrawn from the container bottom (eg, US Pat. No. 2,541,012, US Pat. No. 2,858,229, US The method described in Japanese Patent No. 4,414,341, US Pat. No. 4,504,355, etc.) and the like.

  Prior to casting, the dope solution is preferably filtered off foreign matters such as undissolved matter, dust, and impurities using an appropriate filter medium such as a wire mesh or flannel. For 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 preferably used in the present invention can be obtained by forming a film using the cellulose acylate solution (dope). 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 pressurizing die through a pressurizing quantitative gear pump capable of feeding the dope with high accuracy by the number of rotations, for example, and the dope is run endlessly from the die (slit) of the pressurizing die The dope film (also referred to as a web) is peeled off from the metal support at the peeling point where the metal support is cast almost uniformly around the metal support. The both ends of the obtained web are sandwiched between clips, transported by a tenter while maintaining the width, dried, and then transported by a roll group of a drying device to finish drying, and wound 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.

  In producing a cellulose acylate film by the solvent cast method, first, the prepared cellulose acylate solution (dope) is cast on a drum or a band, 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. For the dope, a method of casting on a drum or band having a surface temperature of 30 ° C. or less is preferably employed, and the metal support temperature is particularly preferably in the range of −10 to 20 ° C. Further, in the present invention, JP 2000-301555 A, JP 2000-301558 A, JP 07-032391, JP 03-193316, JP 05-086212, JP 62-037113, JP The methods described in JP-A No. 02-276607, JP-A No. 55-014201, JP-A No. 02-111511, and JP-A No. 02-208650 can be used.

[Multilayer casting]
The cellulose acylate solution may be cast as a single layer liquid on a smooth band or a 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, a solution containing cellulose acylate is cast from a plurality of casting openings provided at intervals in the traveling direction of the metal support, and the films are laminated while being laminated. For example, the methods described in JP-A-61-158414, JP-A-1-122419, and JP-A-11-198285 can be applied. A film can also 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, the cellulose described in JP-A-56-162617, a flow of a high-viscosity cellulose acylate solution is wrapped with a low-viscosity cellulose acylate solution, and the high-viscosity and low-viscosity cellulose acylate solutions are simultaneously extruded. An acylate film casting method may be used. Furthermore, as described in JP-A-61-94724 and JP-A-61-94725, it is also preferable that the outer solution contains a larger amount of an alcohol component that is a poor solvent than the inner solution. . Alternatively, two casting ports are used, and after the film formed on the metal support is peeled off by the first casting port, the second casting is performed on the side of the film that is in contact with the metal support surface. Thus, a film having a plurality of layers can also be produced, and examples thereof include 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. Further, the cellulose acylate solution may be cast simultaneously with other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorption layer, and a polarizing layer).

  In the conventional single-layer solution, in order to obtain the required film thickness, it is necessary to extrude a high-concentration and high-viscosity cellulose acylate solution, in which case the stability of the cellulose acylate solution tends to deteriorate. In many cases, a solid matter is generated, resulting in a failure or flatness. As a solution to this, by casting a plurality of cellulose acylate solutions from a plurality of casting ports relatively little by little, it becomes possible to extrude a highly viscous solution onto a metal support at the same time. In addition to producing an excellent planar film with improved properties, the use of a concentrated cellulose acylate solution can achieve a reduction in drying load and increase the production speed of the film.

  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 of three or more layers, the total film 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 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 has excellent plasticity. It is also possible to add a plasticizer or an ultraviolet absorber excellent in ultraviolet absorption. Furthermore, it is also a preferred embodiment that a peeling accelerator is contained only in the skin layer on the metal support side. Furthermore, 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 of the layer.

[Casting method]
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. Although there is a method using a reverse roll coater that adjusts with a reverse rotating roll, a method using a pressure die is preferred. 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 mentioned here, it can be carried out by various known methods for casting a cellulose triacetate solution, and each condition is set in consideration of differences in the boiling point of the solvent used. Thus, the same effects as those described in the respective publications can be obtained.

  The endlessly running metal support used for producing the cellulose acylate film preferably used in 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 ( May be referred to as a band). One or more pressure dies may be installed above the metal support. Preferably 1 or 2 groups. When two or more 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 solution temperatures in the process may be the same or different at different points in the process. If they are different, the temperature may be a desired temperature just before casting.

[Dry]
The dope drying on the metal support involved in the production of the cellulose acylate film is generally applied with hot air from the surface side of the metal support (drum or belt), that is, the surface of the web on the metal support. Method, method of applying hot air from the back of the drum or belt, contact the temperature-controlled liquid from the back of the belt or drum opposite the dope casting surface, and heat the drum or belt by heat transfer to control the surface temperature There is a back surface liquid heat transfer method, and 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.

[Stretching treatment]
The cellulose acylate film preferably used in the present invention is preferably adjusted for retardation by stretching treatment. In particular, when the in-plane retardation value of the cellulose acylate film is set to a high value, a method of positively stretching in the width direction, for example, JP-A-62-115035, JP-A-4-152125, A method of stretching the produced film described in JP-A-4-284111, JP-A-4-298310, and JP-A-11-48271 can be used.

  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. Usually, the stretching is performed at 1 to 200%, but the stretching is preferably performed at 1 to 100%, particularly preferably 1 to 50%.

  In order to compensate for the optical anisotropy of the liquid crystal cell and to suppress light leakage when the polarizing plate is viewed obliquely, it is preferable to use a protective film having an in-plane retardation value of 30 nm or more. A cellulose acylate film subjected to the above is used. Specifically, the stretching ratio is preferably 10% or more, more preferably 15% or more.

  In order to suppress light leakage when the polarizing plate is viewed obliquely, it is necessary to arrange the transmission axis of the polarizer and the in-plane slow axis of the cellulose acylate film in parallel. Since the transmission axis of the roll film-like polarizer produced continuously is generally parallel to the width direction of the roll film, it is composed of the roll film-like polarizer and the roll film-like cellulose acylate film. In order to continuously bond the protective film, the in-plane slow axis of the roll film-shaped protective film needs to be parallel to the width direction of the film. Therefore, it is preferable to stretch more in the width direction. The stretching process may be performed in the middle of the film forming process, or the original fabric that has been formed and wound may be stretched. In the former case, stretching may be performed in a state containing a residual solvent, and the stretching can be preferably performed at a residual solvent amount of 2 to 30% by mass.

  The film thickness of the cellulose acylate film preferably used in 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 30 to 30 μm. A range of 150 μm is preferred. Moreover, it is preferable that it is 40-110 micrometers for optical use, 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, and 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, it is preferable to give knurling to at least one end, the knurling 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. is there. This may be a single push or a double push.

The variation in Re ₅₉₀ value in the width direction of the film is preferably ± 5 nm, and more preferably ± 3 nm. Further, the variation of the Rth ₅₉₀ value in the width direction is preferably ± 10 nm, and more preferably ± 5 nm. Moreover, 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]
In this specification, Re _λ and Rth _λ represent in-plane retardation and retardation in the thickness direction at the wavelength λ, respectively. Re _λ is measured in “KOBRA 21ADH” (manufactured by Oji Scientific Instruments) by making light of wavelength λ nm incident in the normal direction of the film. Rth _λ is light having a wavelength of λ nm from a direction inclined by + 40 ° with respect to the normal direction of the film, using Re _λ and an in-plane slow axis (determined by “KOBRA 21ADH”) as an inclination axis (rotation axis). With the retardation value measured by being incident and the in-plane slow axis as the tilt axis (rotation axis), the measurement was performed with light having a wavelength of λ nm incident from a direction inclined by −40 ° with respect to the film normal direction. “KOBRA 21ADH” is calculated based on the retardation values measured in a total of three directions.

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. If the average refractive index is not known, it can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), polystyrene (1.59).
Further, by inputting the assumed average refractive index values and thicknesses, (refractive index in a slow axis direction) n _x by KOBRA 21ADH, (refractive index of the fast axis direction) n _y, n _z (thickness direction Is calculated). “KOBRA 21ADH” also calculates an angle β with respect to the film normal direction that minimizes the retardation value with respect to the light propagating through the film when the in-plane slow axis is the tilt axis.

It is preferable that the Re _λ retardation value and the Rth _λ retardation value satisfy the following formulas (2) and (3), respectively, in order to widen the viewing angle of a liquid crystal display device, particularly a VA mode liquid crystal display device. In particular, a cellulose acylate film is preferable when used for a protective film on the liquid crystal cell side of the polarizing plate.
Formula (2): 0 nm ≦ Re ₅₉₀ ≦ 200 nm
Formula (3): 0 nm ≦ Rth ₅₉₀ ≦ 400 nm
[In the formula, Re ₅₉₀ and Rth ₅₉₀ are values at a wavelength λ = 590 nm (unit: nm). ]

Further, when it is desired to reduce the influence of optical anisotropy of the cellulose acylate film, Re _λ and Rth _{λ of the} protective film (cellulose acylate film) disposed on the liquid crystal cell side are expressed by the formulas (8) to (11). It is preferable to satisfy.
Formula (8): 0 ≦ Re ₅₉₀ ≦ 10
Formula (9): | Rth ₅₉₀ | ≦ 25
Formula (10): | Re ₄₀₀ −Re ₇₀₀ | ≦ 10
Formula (11): | Rth ₄₀₀ −Rth ₇₀₀ | ≦ 35
[Wherein Re ₅₉₀ and Rth ₅₉₀ are values at a wavelength λ = 590 nm, Re ₄₀₀ and Rth ₄₀₀ are values at a wavelength λ = 400 nm, Re ₇₀₀ and Rth ₇₀₀ are values at a wavelength λ = 700 nm (both units: nm). ]

When the cellulose acylate film preferably used in the present invention is used in the VA mode, it is used only on one of the upper and lower sides of the cell (two-sheet type) in which two sheets are used on both sides of the cell. There are two types of forms (single sheet type).
In the case of the two-sheet type, Re ₅₉₀ is preferably 20 to 100 nm, and more preferably 30 to 70 nm. Rth ₅₉₀ is preferably 70 to 300 nm, and more preferably 100 to 200 nm.
In the case of a single sheet type, Re ₅₉₀ is preferably 30 to 150 nm, and more preferably 40 to 100 nm. Rth ₅₉₀ 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 preferably used in the present invention is preferably in the range of −2 ° to + 2 ° with respect to the reference direction of the roll film, from −1 ° to The range of + 1 ° is more preferable, and the range of −0.5 ° to + 0.5 ° is most preferable. 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.

Also, the cellulose acylate film preferably used in the present invention has a difference ΔRe (= Re _10% −Re _80% ) between the Re value at 25 ° C. and 10% RH and the Re value at 25 ° C. and 80% RH. The difference between the Rth value at 25 ° C. and 10% RH and the Rth value at 25 ° C. and 80% RH is ΔRth (= Rth _10% −Rth _80% ) is 0 to 30 nm. It is preferable in order to reduce the color change with time of the apparatus.

Further, the cellulose acylate film preferably used in the present invention 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 was measured by using a cellulose acylate film sample 7 mm × 35 mm, a Karl Fischer method using a moisture measuring device and a sample drying apparatus {“CA-03”, “VA-05”, both Mitsubishi Chemical Corporation)}. Measure with It is calculated by dividing the amount of water (g) by the sample mass (g).

Furthermore, the cellulose acylate film preferably used in the present invention has a moisture permeability of 60 ° C., 95% RH, and 24 hours (in terms of film thickness of 80 μm) of 400 g / m ² · 24 hr or more and 1800 g / m ² · 24 hr or less. It is preferable to reduce the change in color of the liquid crystal display device over time.

The moisture permeability decreases as the thickness of the cellulose acylate film increases, and increases as the thickness decreases. Therefore, it is necessary to provide and convert a reference film thickness in any film thickness sample. In the present invention, the film thickness was converted according to the following formula (13) with the standard film thickness set to 80 μm.
Formula (13): 80 μm-converted moisture permeability = measured moisture permeability × measured film thickness μm / 80 μm.

  The measurement method of moisture permeability is "Polymer Physical 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 at 25 ° C. and 60% RH for 2 hours or more, and then measuring a dynamic viscoelasticity measuring device “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., a frequency of 1 Hz, and a logarithmic axis as a logarithmic axis. The temperature at which the storage elastic modulus shifts from the solid region to the glass transition region when the temperature (° C.) is taken on the linear axis on the horizontal axis is the glass transition temperature Tg. It was. Specifically, on the obtained chart, when the straight line 1 is drawn in the solid region and the straight line 2 is drawn in the glass transition region, the intersection of the straight line 1 and the straight line 2 decreases rapidly when the temperature rises. The glass transition temperature Tg (dynamic viscoelasticity) was determined because the film started to soften and the temperature started to shift to the glass transition region.

  The elastic modulus was measured by adjusting a cellulose acylate film sample 10 mm × 150 mm at 25 ° C. and 60% RH for 2 hours or more, and then a tensile tester “Strograph-R2” {manufactured by Toyo Seiki Seisakusho}} The chucking distance was 100 mm, the temperature was 25 ° C., and the stretching speed was 10 mm / min.

The measurement of the hygroscopic expansion coefficient is the value L _{80% obtained} by measuring the dimension of the film left at 25 ° C. and 80% RH for 2 hours or more with the pin gauge, and the dimension of the film left at 25 ° C. and 10% RH for 2 hours or more. Was obtained by the following formula (14) from the value L _10% measured with a pin gauge.
Formula (14): (L _80% -L _10% ) / (80% RH-10% RH) × 10 ⁶

The cellulose acylate film preferably used in the present invention preferably has a haze in the range 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 at 25 ° C. and 60% RH with a haze meter “HGM-2DP” (manufactured by Suga Test Instruments Co., Ltd.) according to JIS K-6714.

  Furthermore, the cellulose acylate film preferably used in the present invention preferably has a mass change in the range of 0 to 5% by mass when left for 48 hours under conditions of 80 ° C. and 90% RH.

  Furthermore, the cellulose acylate film preferably used in the present invention has a dimensional change when left standing for 24 hours under conditions of 60 ° C. and 95% RH, and is allowed to stand for 24 hours under conditions of 90 ° C. and 5% RH. It is preferable that the dimensional change when placed is in the range of 0 to 5%.

The photoelastic coefficient is preferably 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 was applied to the major axis direction of a cellulose acylate film sample 10 mm × 100 mm, and the retardation at that time was measured with an ellipsometer “M150” {JASCO Corporation}. The photoelastic coefficient was calculated from the amount of change in retardation with respect to stress.

{Cycloolefin polymer}
As the protective film, a cycloolefin polymer can be used instead of cellulose acylate. Examples of cycloolefin polymers include JP-A-1-132625, JP-A-1-132626, JP-A-1-240517, JP-A-63-145324, JP-A-63-264626, JP-A-63-264626. JP 63-218726, JP 2-133413, JP 60-168708, JP 61-120816, JP 60-115912, JP 62-252406 JP-A-60-252407, International Publication No. 2004 / 049011A1, Pamphlet of International Publication No. 2004 / 068226A1, Pamphlet of International Publication No. 2004 / 070463A1 may be used. Moreover, as commercially available cycloolefin polymers, ARTON (manufactured by JSR Corporation), ZEONOR (manufactured by ZEON Corporation), ZEONEX (manufactured by ZEON Corporation), ESINA (Sekisui Chemical Co., Ltd.) Can be used.
When it is desired to reduce the influence of the optical anisotropy of the cycloolefin-based polymer film, Re _λ and Rth _λ of the protective film (cycloolefin-based polymer film) disposed on the liquid crystal cell side are equal to the above formula (8 ) To (11) are preferably satisfied.

<Polarizing plate>
Next, the polarizing plate concerning this invention is demonstrated.
In the polarizing plate according to the present invention, it is preferable that the thickness d _{1 of the} protective film disposed on the liquid crystal cell side and the thickness d _{2 of the} protective film disposed on the side opposite to the liquid crystal cell satisfy the following formula (15).
Formula (15): 0.3 × d ₁ ≦ d ₂ ≦ 1.3 × d ₁
By satisfying the above formula (15), when combining protective films having substantially the same elastic modulus and hygroscopic expansion coefficient, the curl of the polarizing plate is in the range of −30 mm to +15 mm, and a preferable result is obtained.

In the polarizing plate according to the present invention, the elastic modulus E _{1 of the} protective film disposed on the liquid crystal cell side and the elastic modulus E _{2 of the} protective film disposed on the opposite side of the liquid crystal cell satisfy the following formula (16). Is preferred. Thereby, when a protective film having substantially the same thickness and hygroscopic expansion coefficient is combined, the curl of the polarizing plate is in the range of −30 mm to +15 mm, and a preferable result is obtained.
Formula (16): 0.3 × E ₁ ≦ E ₂ ≦ 1.3 × E ₁

Further, the thickness d ₁ and elastic modulus E _{1 of the} protective film disposed on the liquid crystal cell side, and the thickness d ₂ and elastic modulus E _{2 of the} protective film disposed on the opposite side of the liquid crystal cell satisfy the following formula (17). It is preferable.
Formula (17): 0.3 × E ₁ × d ₁ ≦ E ₂ × d ₂ ≦ 1.3 × E ₁ × d ₁
By satisfy | filling numerical formula (17), also when combining the protective film from which thickness and elastic modulus differ, the curl of a polarizing plate becomes the range of -30 mm-+15 mm.

Further, in the polarizing plate according to the present invention, the hygroscopic expansion coefficient C ₁ of the protective film disposed on the liquid crystal cell side and the hygroscopic expansion coefficient C _{2 of the} protective film disposed on the opposite side of the liquid crystal cell are expressed by the following formula (18). It is preferable to satisfy.
Formula (18): 0.3 × C ₁ ≦ C ₂ ≦ 1.3 × C ₁
By satisfying the above mathematical formula, the polarizing plate curl in the case where the humidity when the polarizing plate is bonded to the liquid crystal cell is higher than that during the preparation of the polarizing plate is in the range of −30 mm to +15 mm, and a preferable result is obtained.

  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.

When the cellulose acylate film preferably used in 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 prepared 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.
In the case of using a cycloolefin polymer film as a polarizing plate protective film, as an adhesive, in addition to polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, acrylic polymers, Adhesives such as epoxy polymers, modified olefin polymers, styrene butadiene polymers, and special synthetic rubbers can be used.
A surface treatment may be performed in order to improve adhesiveness. Specific examples include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment, and ultraviolet irradiation treatment. It is also preferable to provide an undercoat layer as described in JP-A-7-333433. From the viewpoint of maintaining the flatness of the film, the temperature of the polymer film in these treatments is preferably Tg (glass transition temperature) or lower.

The polarizing plate is composed of a polarizer and a protective film that protects both sides of the polarizer, and an adhesive layer on at least one surface. Further, a separate film is provided on the adhesive layer surface, and the surface opposite to the separate film of the polarizing plate. A protective film may be pasted on. 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 adhesion layer for bonding a polarizing plate to a liquid crystal cell, and is used for the surface side which bonds a polarizing plate to a liquid crystal cell.
The adhesive layer (meth) acrylic copolymer (A) {or high molecular weight (meth) acrylic copolymer (A ₁₎ and the low molecular weight (meth) acrylic (co) polymer (A _2)} and multiple A composition solution containing a (meth) acrylic copolymer composed of the functional compound (B) is coated on a separate film with a coater such as a die coater, dried, and then transferred to the polarizing plate protective film together with the separate film. It is formed by doing. After apply | coating the solution of the said composition on a polarizing plate protective film and making it dry, you may cover an adhesion layer with a separate film.

  When the stretched cellulose acylate film is used, it is preferable that the polarizer is bonded so that the transmission axis of the polarizer and the slow axis of the cellulose acylate film coincide with each other.

  A polarizing plate produced under polarizing plate crossed Nicol has an orthogonal accuracy within 1 ° between the slow axis of the cellulose acylate film preferably used in the present invention and the absorption axis of the polarizer (axis perpendicular to the transmission axis). If this is the case, the degree of polarization performance under the crossed Nicols polarizing plate will be reduced, causing light leakage, and insufficient black level and contrast will not be obtained when combined with a liquid crystal cell. Therefore, the difference between the direction of the slow axis of the cellulose acylate film preferably used in the present invention and the direction of the transmission axis of the polarizing plate is preferably within 1 °, preferably within 0.5 °. Is more preferable.

  Attaching a polarizing plate to a liquid crystal cell is generally performed by attaching a polarizing plate to a suction jig with a large number of holes, peeling off a separate film on the surface of the adhesive layer formed by applying an adhesive. The layer surface is brought into contact with the liquid crystal cell, and is applied by pressing with a roller. At this time, if the polarizing plate is curled so as to be concave on the liquid crystal cell side, the suction to the suction jig is not sufficiently performed, and the attachment angle to the suction jig is shifted, so that the sticking to the liquid crystal cell is not possible. The attachment angle is shifted and display characteristics as designed cannot be obtained. In addition, the polarizing plate may fall off from the suction jig during the pasting to the liquid crystal cell, and the pasting work cannot be continued, and the work may be interrupted.

  In order not to cause such polarizing plate sticking failure, the curling amount of the polarizing plate is preferably in the range of −30 mm to +15 mm, more preferably in the range of −20 mm to +5 mm, and −10 mm to 0 mm. The most preferable range is as follows. Here, a case where the surface is affixed to the liquid crystal cell (adhesive coating surface = adhesive layer surface) side is referred to as + (plus) curl, and a case where the surface is convex is referred to as − (minus) curl. The curl amount can be controlled by adjusting the relationship among the thickness, elastic modulus, and hygroscopic expansion coefficient of the protective film on the liquid crystal cell side and the protective film on the opposite side of the liquid crystal cell.

  The curl was measured after placing a polarizing plate of 230 mm x 305 mm on a flat table with the surface where the end is lifted down and leaving it in an environment of 25 ° C and 60% RH for 2 hours or longer. The height of the farthest position of the end of the polarizing plate is measured with respect to the surface of the table, and is defined as the curl amount. When a separate film and a protective film were attached, the measurement was performed with these films attached.

[Surface treatment of cellulose acylate film]
The cellulose acylate film preferably used in 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 under a low pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferred. A plasma-excitable gas is a gas that is plasma-excited under the above-mentioned conditions, and examples thereof include 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 above-mentioned public technical number 2001-1745 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.

[Alkaline saponification]
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 without forming irregularities. 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.

  Furthermore, the polarizing plate according to the present invention is preferably one in which at least one layer of a hard coat layer, an antiglare layer or an antireflection layer is provided on the surface of the protective film on at least one 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 disposed on the side opposite to the liquid crystal cell. It is preferable to provide at least one layer of a coat layer, an antiglare layer or an antireflection layer. In addition, it is not necessary to provide each layer as a separate layer, for example, by providing an antireflection layer and a hard coat layer with an antiglare function, instead of providing two layers of an antireflection layer and an antiglare layer, You may make it function as an anti-glare antireflection layer.

(Antireflection layer)
In the present invention, at least a light scattering layer and a low refractive index layer are laminated in this order on the protective film of the polarizing plate, or a medium refractive index layer, a high refractive index layer, and a low refractive index on the protective film. An antireflection layer in which rate layers are laminated in this order is suitably provided. Preferred examples thereof are described below. In the former configuration, the specular reflectance is generally 1% or more, which is referred to as a low reflection (LR) film. In the latter configuration, it is possible to realize a mirror reflectivity of 0.5% or less, and this is called an Anti Reflection (AR) film.

[LR film]
A preferred example of an antireflection layer (LR film) in which a light scattering layer and a low refractive index layer are provided on a protective film of a polarizing plate 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, two to four layers.

  The antireflection layer has an uneven surface shape, centerline average roughness Ra is 0.08 to 0.40 μm, 10-point average roughness Rz is 10 times or less Ra, average unevenness distance Sm is 1 to 100 μm, unevenness The standard deviation of the height of the convex part from the deepest part is 0.5 μm or less, the standard deviation of the average unevenness distance Sm with respect to the center line is 20 μm or less, and the surface with the inclination angle of 0 to 5 ° is 10% or more. It is preferable that it is designed so that sufficient anti-glare property and visual uniform matte feeling can be achieved.

Further, the ratio between the minimum value and the maximum value of the reflectance when the color of the reflected light under the C light source is in the range of a ^* value −2 to 2, b ^* value −3 to 3 and 380 nm to 780 nm. It is preferable that the color is 5 to 0.99 because the color of the reflected light becomes neutral. Furthermore, 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. Furthermore, if a 120 μm × 40 μm grid is inserted between the surface light source and the antireflection layer and the luminance distribution is measured on the film, the standard deviation of the luminance distribution is 20 or less. Since glare when the polarizing plate of the invention is applied is reduced, it is preferable.

The antireflection layer that can be used in the present invention suppresses reflection of external light by setting its optical properties to a specular reflectance of 2.5% or less, a transmittance of 90% or more, and a 60 ° glossiness of 70% or less. This is preferable because visibility is improved. In particular, the specular reflectance is more preferably 1% or less, and 0.5%
Most preferably: 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 .Transparent image clarity at 5 mm, 20% to 50%, vertical transmission light / transmittance ratio in the direction inclined by 2 ° from vertical is 1.5 to 5.0, thereby preventing glare on a high-definition LCD panel. This is preferable because blurring of characters and the like is reduced.

(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. Furthermore, the low refractive index layer preferably satisfies the following formula (19) from the viewpoint of reducing the reflectance.
Formula (19): (m / 4) λ × 0.7 <n _L d _L <(m / 4) λ × 1.3
In the formula, m is a positive odd number, n _L is the refractive index of the low refractive index layer, and d _L is the film thickness (nm) of the low refractive index layer. Further, λ is a wavelength and 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.
As the fluorine polymer, a fluorine-containing polymer which is crosslinked by heat or ionizing radiation and having a dynamic friction coefficient 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 is preferable. When the polarizing plate according to 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 seal or memo, and the peel strength is measured when measured with a tensile tester. It is preferably 500 gf or less, more preferably 300 gf or less, and most preferably 100 gf or less. Further, the higher the surface hardness measured with a microhardness meter, the harder it is to scratch, and the surface hardness is 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 perfluoroalkyl group-containing silane compounds {for example, hydrolysates and dehydrated condensates of (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.), (Meth) acrylic acid partial or fully fluorinated alkyl ester derivatives [e.g. "Biscoat 6FM" {manufactured by Osaka Organic Chemical Industry Co., Ltd.} or "M-2020" {manufactured by Daikin Industries Ltd.}], complete or Partially fluorinated vinyl ethers and the like can be mentioned, and perfluoroolefins are preferable, and hexafluoropropylene is particularly preferable from the viewpoint of refractive index, solubility, transparency, availability, and the like.

  As a structural unit for imparting crosslinking reactivity, a structural unit obtained by polymerization of a monomer having a self-crosslinkable functional group in the molecule in advance, such as glycidyl (meth) acrylate or glycidyl vinyl ether, a carboxyl group or a hydroxy group, Polymerization of monomers having amino groups, sulfo groups, etc. {eg (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, maleic acid, crotonic acid, etc.} Or a structural unit obtained by introducing a crosslinking reactive group such as a (meth) acryloyl group into the structural unit by a polymer reaction (for example, a method in which acrylic acid chloride is allowed to act on a hydroxy group). ) It is.

  In addition to the fluorine-containing monomer unit and the structural unit for imparting crosslinking reactivity, a monomer that does not contain a fluorine atom can be copolymerized as appropriate from the viewpoint of solubility in a solvent, film transparency, and the like. 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, vinyltoluene, 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 (Nt-butylacrylamide, N-cyclo) Hexyl acrylamide), methacrylamides, and acrylonitrile derivatives.

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

(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 including a binder for imparting hard coat properties, matte particles for imparting light diffusibility, and inorganic fillers for increasing the refractive index, preventing crosslinking shrinkage, and increasing the strength as necessary. The In addition, 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 the film thickness of the light scattering layer is not less than the lower limit, problems such as insufficient hardware properties are unlikely to occur, and if the thickness is not more than the upper limit, inconveniences such as curling and brittleness are deteriorated and workability is insufficient. Is preferable because it is difficult to cause.

  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 {for example, 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- Chlorohexane tetramethacrylate, polyurethane polyacrylate, polyester polyacrylate}, modified ethylene oxide, vinylbenzene and derivatives thereof (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4 -Divinylcyclohexanone), vinyl sulfone (e.g. divinyl sulfone), acrylamide (e.g. methylene bisacrylamide) 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 these monomers 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. Accordingly, 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 is applied. It can harden | cure by the polymerization reaction by and can form an antireflection layer. 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 liquid containing a polyfunctional epoxy compound, a photoacid generator or a thermal acid generator, matte particles and an inorganic filler is prepared, and the coating liquid is applied onto a protective film and then cured by ionizing radiation or heat polymerization reaction. Thus, an antireflection layer 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 this crosslinkable functional group reacts. A crosslinked structure may be introduced into the binder polymer.

Examples of the crosslinkable functional group include an isocyanate group, an epoxy group, an aziridine group, an oxazoline group, an aldehyde group, a carbonyl group, a hydrazine group, a carboxyl group, a methylol group, and an 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 diameter 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. Specific examples of the matte particles include preferably particles of inorganic compounds such as silica particles and TiO ₂ particles; and resin particles such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles. It is done. 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.

  Further, 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 particles having a particle size of 20% or more than the average particle size are defined as coarse particles, the proportion of coarse particles 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 matte particles, in order to increase the refractive index of the layer. Thus, it is preferable that an inorganic filler having an average particle diameter 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 difference in refractive index from the mat particles, it is also preferable to use a silicon oxide in order to keep the refractive index of the light scattering layer using the high refractive index mat particles low. 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 in terms 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%.

  Such a filler does not scatter because the particle size is sufficiently smaller than the wavelength of light, 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 or 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 layer preferably used in 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.

[AR film]
Next, an antireflection layer (AR film) 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.

An 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. .
Refractive index of high refractive index layer> refractive index of medium refractive index layer> refractive index of protective film> refractive index of low refractive index layer

Further, a hard coat layer may be provided between the protective film and the medium refractive index layer. Further, it may be composed of a medium refractive index hard coat layer, a high refractive index layer and a low refractive index layer. For example, JP-A-8-122504, 8-110401, 10-300902, Examples thereof include antireflection layers described in JP-A-2002-243906, JP-A No. 2000-11706, and the like.
Further, other functions may be imparted to each layer. For example, an antifouling low refractive index layer and an antistatic high refractive index layer (for example, JP-A Nos. 10-206603 and 2002-2002). 243906 publication etc.) etc. are mentioned.

  The haze of the antireflection layer is preferably 5% or less, more preferably 3% or less. Further, the surface 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 K-5400.

(High refractive index layer and medium refractive index layer)
The layer having a high refractive index of the antireflection layer 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 agent, etc .: JP-A Nos. 1-295503, 11-153703, 2000-9908, Anionic compounds or organometallic coupling agents: JP 2001-310432 A, etc., core-shell structure with high refractive index particles as the core (JP 2001-166104 A, etc.), combined use of specific dispersant (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 the partial condensates thereof, for example, JP-A 2000-47004, 2001-315242, 2001-31871, 2001- And compounds described in Japanese Patent No. 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 sequentially laminated 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, imparting slipperiness to the surface is effective, and conventionally known means for thin film layers including introduction of silicone, introduction of fluorine, and the like can be applied.

The fluorine-containing compound is preferably a compound containing a crosslinkable or polymerizable functional group containing a fluorine atom in a range of 35 to 80% by mass, for example, paragraph numbers [0018] to [0026] of JP-A-9-222503. Examples thereof include the compounds described in paragraph Nos. [0019] to [0030] of JP-A-11-38202, paragraph numbers [0027] to [0028] of JP-A-2001-40284, JP-A 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 preferably a compound having a polysiloxane structure, 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 [for example, “Silaplane” {manufactured by Chisso Corporation etc.]], polysiloxane containing silanol groups at both ends (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 and the siloxane polymer having a crosslinking or polymerizable group is performed simultaneously with the application of the coating composition for forming the outermost layer containing a polymerization initiator, a sensitizer and the like. Alternatively, it is preferable to form the low refractive index layer by light irradiation or heating after coating.

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 is also preferable.
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). Etc.) and the like.

  The low refractive index layer has an average primary particle diameter of 1 to 150 nm such as a filler {eg, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride) as additives other than the above. Low refractive index inorganic compounds, organic fine particles described in paragraphs [0020] to [0038] of JP-A-11-3820}, silane coupling agents, slip agents, surfactants, and the like. .

  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 protective film 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 preferred are hydrolyzable functional group-containing organometallic compounds and organoalkoxysilyl compounds.

Specific examples of these compounds are the same as those exemplified for the high refractive index layer.
Specific examples of the 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 surface strength of the hard coat layer is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K-5400. Further, in the Taber test according to JIS K-5400, 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)
When an antistatic layer is provided, 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 used as the metal that forms the metal oxide without coloring, and a metal oxide containing these as main components is used. It is preferable.

Specific examples of the metal oxide 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, etc. These composite oxides are good, and ZnO, TiO ₂ and SnO ₂ are particularly 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 Patent Publication No. 59-6235, a material obtained by adhering the above metal oxide to other crystalline metal particles or fibrous materials (for example, titanium oxide) may be used. Note that the volume resistance value and the surface resistance value are different physical property values and cannot be simply compared. However, in order to secure conductivity of 10 ⁻⁸ (Ωcm ⁻³ ) or less in volume resistance value, The prevention layer should just have a surface resistance value of 10 ⁻¹⁰ (Ω / □) or less, more preferably 10 ⁻⁸ (Ω / □). The surface resistance value of the antistatic 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.

[Liquid Crystal Display]
The liquid crystal display device of the present invention includes at least the polarizing plate, and includes a reflection type, a transflective type, a transmission type liquid crystal display device and the like. A liquid crystal display device generally includes a polarizing plate, a liquid crystal cell, and a retardation plate, a reflection layer, a light diffusion layer, a backlight, a front light, a light control film, a light guide plate, a prism sheet, a color filter, etc. Although comprised from a member, in this invention, there is no restriction | limiting in particular except the point which makes it essential to use the said polarizing plate. The liquid crystal cell is not particularly limited, and a general liquid crystal cell such as a liquid crystal layer sandwiched between a pair of transparent substrates provided with electrodes can be used. The transparent substrate constituting the liquid crystal cell is not particularly limited as long as the liquid crystal material constituting the liquid crystal layer is aligned in a specific alignment direction. Specifically, a transparent substrate in which the substrate itself has a property of orienting liquid crystals, a transparent substrate in which an alignment film having the property of orienting liquid crystals is provided, but the substrate itself lacks the alignment ability. Either can be used. Moreover, a well-known thing can be used for the electrode of a liquid crystal cell. Usually, it can be provided on the surface of the transparent substrate in contact with the liquid crystal layer, and when a substrate having an alignment film is used, it can be provided between the substrate and the alignment film. The material exhibiting liquid crystallinity for forming the liquid crystal layer is not particularly limited, and examples thereof include various ordinary low-molecular liquid crystalline compounds, high-molecular liquid crystalline compounds, and mixtures thereof that can constitute various liquid crystal cells. Moreover, a pigment | dye, a chiral agent, a non-liquid crystalline compound, etc. can also be added to these in the range which does not impair liquid crystallinity.

  In addition to the electrode substrate and the liquid crystal layer, the liquid crystal cell may include various components necessary for forming various types of liquid crystal cells described later. As the liquid crystal cell system, TN (Twisted Nematic) system, STN (Super Twisted Nematic) system, ECB (Electrically Controlled Birefringence) system, IPS (In-Plane Switching) system, VA (In-Plane Switching) system, VA (In-Plane Switching) system, VA (In-Plane Switching system) Alignment), PVA (Patterned Vertical Alignment), OCB (Optically Compensated Birefringence), HAN (Hybrid Aligned Nematic), ASM crocell) method, halftone gray scale method, domain division method, or display method using ferroelectric liquid crystal or antiferroelectric liquid crystal. The driving method of the liquid crystal cell is not particularly limited, and a passive matrix method used for STN-LCD and the like, and an active matrix method using an active electrode such as a TFT (Thin Film Transistor) electrode and a TFD (Thin Film Diode) electrode, Any driving method such as a plasma addressing method may be used. A field sequential method that does not use a color filter may be used.

  The polarizing plate in the present invention is preferably used for a reflective, transflective, and transmissive liquid crystal display device. Moreover, the polarizing plate in this invention is preferably used also as a brightness improvement film | membrane by combining with a cholesteric liquid crystal film. The reflective liquid crystal display device has a configuration in which a reflector, a liquid crystal cell, and a polarizing plate are laminated in this order. The retardation plate is disposed between the reflecting plate and the polarizing film (between the reflecting plate and the liquid crystal cell or between the liquid crystal cell and the polarizing film). The reflector may share the liquid crystal cell and the substrate. The transflective liquid crystal display device includes an electro-liquid crystal cell, a polarizing plate disposed closer to the viewer than the liquid crystal cell, and at least one retardation plate disposed between the polarizing plate and the liquid crystal cell. And at least a transflective layer disposed behind the liquid crystal cell as viewed from the viewer, and at least one retardation plate and a polarizing plate behind the transflective layer as viewed from the viewer. Have In this type of liquid crystal display device, it is possible to use both a reflection mode and a transmission mode by installing a backlight.

  In the liquid crystal display device, the polarizing plate of the present invention functions as an elliptically polarizing plate or a circularly polarizing plate. The liquid crystal display device according to the present invention uses the polarizing plate of the present invention at least at one location.

  The polarizing plate of the present invention is not limited to the above uses, and can be used for various other uses. For example, it can be used for an antireflection film such as a host-guest type liquid crystal display device, a touch panel, an electroluminescence (EL) element, a reflection type polarizing plate, and the like.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

Example 1
<Preparation of cellulose acylate film>
(Preparation of cellulose acetate solution)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution A.
―――――――――――――――――――――――――――――――――――
Composition of cellulose acetate solution A ――――――――――――――――――――――――――――――――――――
Cellulose acetate with an acetyl substitution degree of 2.94 100.0 parts by mass Methylene chloride (first solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass ――――――――――――― ――――――――――――――――――――――

(Preparation of matting agent solution)
20 parts by mass of silica particles having an average particle diameter of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) and 80 parts by mass of methanol were thoroughly mixed for 30 minutes to obtain a silica particle dispersion. This dispersion was put into a disperser together with the following composition, and further stirred for 30 minutes or more to dissolve each component to prepare a matting agent solution.
―――――――――――――――――――――――――――――――――
Matting agent solution composition ――――――――――――――――――――――――――――――――――
Silica particle dispersion with an average particle size of 16 nm 10.0 parts by weight Methylene chloride (first solvent) 76.3 parts by weight Methanol (second solvent) 3.4 parts by weight Cellulose acetate solution A 10.3 parts by weight ―――――――――――――――――――――――――――――

(Preparation of additive solution)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.
――――――――――――――――――――――――――――――
Additive solution composition ――――――――――――――――――――――――――――――
The following optical anisotropy reducing agent 49.3 parts by mass The following wavelength dispersion adjusting agent 4.9 parts by mass Methylene chloride (first solvent) 58.4 parts by mass Methanol (second solvent) 8.7 parts by mass Cellulose acetate solution A 12.8 parts by mass ――――――――――――――――――――――――――――――

Optical anisotropy reducing agent

Chromatic dispersion modifier

(Preparation of cellulose acylate film)
94.6 parts by mass of the cellulose acetate solution A, 1.3 parts by mass of the matting agent solution, and 4.1 parts by mass of the additive solution were mixed after filtration, and cast using a band casting machine. In the above composition, the mass ratio of the optical anisotropy reducing agent and the wavelength dispersion adjusting agent to cellulose acetate was 12% and 1.2%, respectively. The film was peeled off from the band with a residual solvent amount of 30% and dried at 140 ° C. for 40 minutes to produce a long cellulose acylate film having a thickness of 80 μm. The in-plane retardation (Re) of the obtained film was 1 nm (the slow axis was a direction perpendicular to the longitudinal direction of the film), and the retardation (Rth) in the thickness direction was −1 nm.

<Preparation of retardation plate 1b>
(Formation of alignment film)
After saponifying the surface of the cellulose acylate film produced above, an alignment film coating solution having the following composition was continuously applied with a # 14 wire bar. The film was formed by drying with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds. Next, the formed film was continuously rubbed in a direction of 45 ° with respect to the longitudinal direction of the film to form an alignment film.
――――――――――――――――――――――――――
Composition of alignment film coating solution ――――――――――――――――――――――――――
The following modified polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde 0.5 parts by weight ――――――――――――――――――――――――――――

Modified polyvinyl alcohol

(Formation of first optically anisotropic layer)
A coating solution containing a discotic liquid crystalline compound having the following composition was continuously applied to the prepared alignment film with a # 3.6 wire bar. In order to dry the solvent of the coating solution and to mature the orientation of the discotic liquid crystal compound, the coating liquid was heated with warm air at 100 ° C. for 30 seconds and further with warm air at 130 ° C. for 60 seconds. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation to form a first optical anisotropic layer, and the retardation film 1a was produced.

―――――――――――――――――――――――――――――――――
Composition of the first optically anisotropic layer coating solution ―――――――――――――――――――――――――――――――――
91 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by mass of the following discotic liquid crystalline compound Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass Fluoropolymer P-19 0.4 part by mass Pyridinium salt I-30 0.5 part by mass Methanol 30 parts by mass Methyl ethyl ketone 165 parts by mass ――――――――――――――――――――――――――――――

Discotic liquid crystalline compounds

  Using an automatic birefringence meter (KOBRA-21ADH, manufactured by Oji Scientific Instruments Co., Ltd.), Re (0) = 121.6 nm, Re (40) = 112.8 nm, Re at 589 nm of the prepared retardation plate 1a. (−40) = 112.7 nm was measured, and Rth = −61 nm and Nz = 0. From these results, the average inclination angle of the disc surface of the discotic liquid crystalline compound with respect to the film surface was 90 °, and it was confirmed that the discotic liquid crystalline compound was aligned perpendicularly to the film surface. The direction of the slow axis was parallel to the rubbing direction of the alignment film, and the angle formed with the longitudinal direction of the support was 45 °.

(Formation of second optically anisotropic layer)
An alignment film was formed in the same manner as described above on the first optical anisotropic layer of the retardation plate 1a produced above. A coating solution containing a rod-like liquid crystalline compound having the following composition was continuously applied onto the alignment film with a # 3.0 wire bar. In order to dry the solvent of the coating solution and to mature the alignment of the rod-like liquid crystal compound, it was heated for 60 seconds with hot air at 90 ° C. Subsequently, the orientation of the liquid crystal compound was fixed by UV irradiation to form a second optically anisotropic layer. Subsequently, the surface of the cellulose acylate film opposite to the surface on which the optically anisotropic layer was formed was continuously saponified to produce a retardation plate 1b.

―――――――――――――――――――――――――――――――――
Composition of the second optically anisotropic layer coating solution ―――――――――――――――――――――――――――――――――
The following rod-like liquid crystalline compound A 100 parts by mass photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by mass sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass fluorinated polymer P-22 0.2 parts by mass The following fluoropolymer (D) 0.2 parts by mass pyridinium salt I-12 2 parts by mass Methanol 30 parts by mass Methyl ethyl ketone 168 parts by mass ―――――――――――――――― ―――――――――――――――――

Rod-like liquid crystalline compound A

Fluoropolymer (D)

  In the same manner as above, Re (0) = 121.6 nm, Re (40) = 85.3 nm and Re (−40) = 85.4 nm at 589 nm of the retardation film 1 b were measured, and Rth = −243 nm and Nz = −1.5. Met. From these results, the rod-like liquid crystalline compound is formed on the film surface (optical) on the first optical anisotropic layer in which the discotic liquid crystalline compound is oriented perpendicular to the film surface (optical anisotropic layer surface). It was confirmed that the second optically anisotropic layer oriented perpendicularly to the (anisotropic layer surface) was formed. The direction of the slow axis was parallel to the rubbing direction of the alignment film, and the angle formed with the longitudinal direction of the support was 45 °.

<Synthesis and properties of adhesives>
Synthesis example 1
(1) Preparation of (meth) acrylic copolymer (A) solution (meth) acrylic acid ester (a ₁ ), homopolymer having a composition ratio shown in Table 1 and a Tg of less than −30 ° C. A reaction vessel is charged with a compound (a ₂ ) having a vinyl group having a Tg of −30 ° C. or higher, a functional group-containing monomer (a ₃ ) having reactivity with a polyfunctional compound, and a polymerization initiator. After replacing this reaction vessel with nitrogen gas, the reaction was carried out at the reaction temperature and time shown in Table 1 in a nitrogen atmosphere while stirring. (Meth) acrylic copolymer No. 1, 2, 3, 5 and 6 were diluted with ethyl acetate after the reaction to obtain a polymer solution with a solid content concentration of 20% by mass. (Meth) acrylic copolymer No. 4 and 7 were diluted with toluene after the reaction to obtain a solid content concentration of 20% by mass to obtain a (meth) acrylic copolymer solution.

[Measurement of mass average molecular weight]
The weight average molecular weight (Mw) in terms of styrene of each copolymer in the (meth) acrylic copolymer solution was determined by gel permeation chromatography (GPC). The measurement conditions are shown below. The obtained results are shown in Table 1.

Device name: “HLC-8120” {manufactured by Tosoh Corporation}
Column: “G7000HXL” 7.8 mm ID × 30 cm 1 {manufactured by Tosoh Corporation}
"GMHXL" 7.8mmID x 30cm 2 pieces {manufactured by Tosoh Corporation}
"G2500HXL" 7.8mmID x 30cm 1 {manufactured by Tosoh Corporation}
Sample concentration: diluted with tetrahydrofuran to 1.5 mL / mL Mobile phase solvent: tetrahydrofuran Flow rate: 1.0 mL / min Column temperature: 40 ° C.

(2) Preparation of pressure-sensitive adhesive solution The (meth) acrylic copolymer (A) solution prepared in Synthesis Example 1 was mixed so as to have a solid content ratio shown in Table 2, and the polyfunctional compound shown in Table 2 (Crosslinking agent) (B) was added and sufficiently stirred to obtain an adhesive solution.

[Measurement of gel fraction]
The gel fraction was measured as follows. The pressure-sensitive adhesive solution was applied on a 25 μm thick PET film using a die coater and then dried. The coating amount of the pressure-sensitive adhesive solution was adjusted so that the thickness after drying was 25 μm. About 20 mL of the dried adhesive layer was soaked in about 10 mL of chloroform, insoluble components were filtered through a 0.45 μm filter, and what remained on the filter was dried, and the mass was measured to obtain the mass Mg of the gel component (crosslinking component). Furthermore, the filtrate was dried and the mass of the residue was measured to obtain the mass Ms of the sol (uncrosslinked component), and the gel fraction was calculated by the following formula.
Gel fraction (%) = Mg / (Mg + Ms) × 100
Table 2 shows the gel fraction immediately after coating the adhesive layer. The gel fractions shown in Table 3 were measured under three conditions: immediately after coating the adhesive layer, one month after coating, and one month after coating and further heated at 80 ° C. for 500 hours.

Synthesis Example 2: Preparation of pressure-sensitive adhesive solution 13 Ethyl acetate so that 100 parts by mass of butyl acrylate, 5 parts by mass of acrylic acid, and 0.5 parts by mass of 2,2′-azobisbutyronitrile have a monomer concentration of 60% by mass. Then, the polymer 1 was polymerized at 60 ° C. for 8 hours to obtain a polymer 1 solution. 1 part by mass of an isocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by mass of the solid content of the polymer 1 and stirred sufficiently to prepare an adhesive solution 13.

Synthesis Example 3: Preparation of pressure-sensitive adhesive solution 14 After dissolving 100 parts by mass of butyl acrylate, 5 parts by mass of acrylic acid, and 0.5 parts by mass of benzoyl peroxide in ethyl acetate so that the monomer concentration becomes 60% by mass, 60 ° C. Was polymerized for 8 hours to obtain a solution of polymer 2. 1 part by mass of an isocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by mass of the solid content of the polymer 2, and the mixture was sufficiently stirred to prepare an adhesive solution 14.

Synthesis Example 4: Preparation of pressure-sensitive adhesive solution 15 Ethyl acetate so that 100 parts by mass of butyl acrylate, 5 parts by mass of acrylic acid, and 0.5 parts by mass of 2,2′-azobisbutyronitrile may have a monomer concentration of 60% by mass. Then, the solution was polymerized at 60 ° C. for 8 hours to obtain a solution of polymer 3. 0.2 parts by mass of an isocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by mass of the solid content of the polymer 3, and the mixture was sufficiently stirred to prepare an adhesive solution 15. .

Synthesis Example 5: Preparation of pressure-sensitive adhesive solution 16 70 parts by mass of butyl acrylate, 30 parts by mass of methyl acrylate, 5 parts by mass of acrylic acid, 0.5 parts by mass of 2,2′-azobisbutyronitrile and a monomer concentration of 60 parts by mass % And then polymerized at 60 ° C. for 8 hours to obtain a polymer 4 solution. 1 part by mass of an isocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by mass of the solid content of the polymer 4, and the mixture was sufficiently stirred to prepare an adhesive solution 16.

  As the adhesive 17, a rubber adhesive was used.

[Measurement of creep value]
A polarizing plate 90 having an adhesive layer 80 formed thereon was attached to a non-crisp glass plate (product number 1737, manufactured by Corning) 70 that had been washed with water and dried as shown in FIG. The affixing area was 10 mm for the horizontal a and 10 mm for the vertical b. The initial adhesion pressure was 5 kg / cm ² . Thereafter, the adhesive pressure was removed, and a load W of 200 g was applied for 1 hour in an atmosphere at 50 ° C., the load was taken out in a room temperature atmosphere, and the creep amount of the adhesive was measured. The polarizing plate on which the adhesive layer was formed was replaced with an untested one, and the temperature of the atmosphere was set to 25 ° C., 70 ° C., and 90 ° C., and the creep amount was measured in the same manner as in the case of 50 ° C.

[Measurement of adhesive strength]
The adhesive strength of the adhesive layer was measured based on JIS Z 0237 “Testing method for adhesive tape and adhesive sheet”. Specifically, a polarizing plate on which an adhesive layer having a length of 100 mm and a width of 25 mm was formed, and this was attached to a non-crisp glass plate (product number 1737, manufactured by Corning) that had been washed and dried. Next, the 2 kg roller was reciprocated once and left at 25 ° C. for 20 minutes. Using the tensile tester (TMC-1kNB, manufactured by Minebea Co., Ltd.) based on the above JIS regulations, the polarizing plate is 25 ° C., peeling rate 300 mm / min, 90 ° peel. The adhesive force of the pressure-sensitive adhesive layer was measured by measuring the force at the time of peeling from the glass plate.
Two cases, when the polarizing plate is attached to the glass plate without heat treatment and when it is left in an autoclave at 50 ° C. and 5 atm for 15 minutes to mature for 5 hours at 70 ° C. The adhesive force was measured.

[Measurement method of elastic modulus]
The pressure-sensitive adhesive solution was applied on a 25 μm-thick PET film using a die coater and then dried. Here, it adjusted so that the thickness of the adhesion layer after drying might be set to 25 micrometers. Further, a PET film was placed on the adhesive layer and aged at 25 ° C. and 60% RH for 7 days. The pressure-sensitive adhesive layer was laminated to a thickness of 1 mm, cut into a size of 20 mm long × 5 mm wide, and stressed under the conditions of a tensile speed of 300 mm / min and a distance between chucks of 10 mm using the tensile tester. The strain curve was determined and the elastic modulus was determined. The atmosphere temperature at the time of measurement was two conditions of 25 ° C. and 90 ° C.

[Measurement of shear modulus]
According to the tensile shear bond strength test method of the adhesive of JIS K 6850, the tensile stress-strain curve was obtained by pulling at a pulling speed of 1 mm / min. Since JIS K 6850 does not show a method for calculating the elastic modulus, the value derived by the calculation method shown in item 8 (3) of the plastic film and sheet tensile test method of JIS K 7127 is used as the adhesive layer. The shear modulus of elasticity.
[Tg measurement]
The Tg was measured using a differential thermal scanning calorimeter (DSC2910, manufactured by TA Instruments). The polymer was put in an aluminum pan, the temperature was increased from −160 ° C. to + 100 ° C. at 10 ° C./min, and then the temperature was decreased from + 100 ° C. to −160 ° C. at 10 ° C./min, and Tg was obtained from the data of the temperature decrease process. . In Table 3, Tg is a measured value of the (meth) acrylic copolymer.

The physical property values of the pressure-sensitive adhesives 13 to 17 are summarized in Table 3.

<Preparation of Polarizing Plate 1>
A roll-shaped polyvinyl alcohol film having a thickness of 80 μm continuously dyed in an aqueous iodine solution was stretched 5 times in the transport direction and dried to obtain a long polarizing film. One side of the polarizing film has a surface on which the optically anisotropic layer of the produced retardation plate 1b is not formed, and the other side has a viewing angle widening film (WV FILM wide view A WV SA 128 Fuji Photo Film). (Manufactured by Co., Ltd.) was continuously pasted using a polyvinyl alcohol-based adhesive to produce a long polarizing plate 1. The absorption axis of the polarizing film was parallel to the film longitudinal direction, and the slow axis of the wide view film was orthogonal to the film longitudinal direction. The angle formed by the absorption axis of the polarizing film and the slow axis of the retardation film 1b was 45.0 °.

<Preparation of Polarizing Plate 2>
A long cholesteric liquid crystal film was prepared in the same manner as described in the examples of JP-A-2003-337221. A surface of the polarizing plate 1 on the side opposite to the wide view film and a cholesteric liquid crystal film were continuously bonded to prepare a long polarizing plate 2.

(Coating of adhesive layer)
Application of the adhesive layer to the polarizing plate 2 was performed as follows.
The pressure-sensitive adhesive solution was applied on a 25 μm-thick PET film using a die coater and then dried. Here, it adjusted so that the thickness of the adhesion layer after drying might be set to 25 micrometers. Further, the pressure-sensitive adhesive layer coated on the PET film was transferred to the wide-view film side of the polarizing plate 2 produced above, and pressure-sensitive adhesive solutions No. 1 to 17 were transferred and aged at 25 ° C. and 60% RH for 7 days. The polarizing plate samples 1 to 17 were prepared.
A PET separator was attached to the pressure-sensitive adhesive layer side of the polarizing plate produced as described above, and a PET protective film was attached to the side opposite to the pressure-sensitive adhesive layer.

Example 2
<Mounting on LCD panel>
Of the pair of polarizing plates provided in a liquid crystal display device (AQUAS LC20C1S, manufactured by Sharp Corporation) using a TN type liquid crystal cell, only the polarizing plate on the backlight side is peeled off, and the above-prepared polarizing plate sample is used instead. 1-17 were affixed through the adhesion layer so that a wide view film might become a liquid crystal cell side. The transmission axis of the polarizing plate on the viewer side and the transmission axis of the polarizing plate on the backlight side were arranged to be in the O mode.

  After peeling off the protective film, the viewing angle (contrast ratio in the range of 10 or more) was calculated from the luminance measurement of black display and white display using a measuring instrument “EZ-Contrast 160D” (manufactured by ELDIM). When any polarizing plate was used, good viewing angle characteristics with polar angles of 80 ° or more were obtained in all directions.

[Light leakage and peeling of polarizing plate by durability test]
The liquid crystal display device manufactured in Example 2 was subjected to a durability test under the following two conditions.
(1) Hold in an environment of 60 ° C. and 90% RH for 200 hours, take out to 25 ° C. and 60% RH environment, display the liquid crystal display device black 24 hours later, and check the light leakage strength and whether the polarizing plate is peeled off from the liquid crystal panel evaluated. The results are shown in Table 4.
(2) Hold in an 80 ° C. dry environment for 200 hours, take out to 25 ° C. and 60% RH environment, display the liquid crystal display device in black after 1 hour, and evaluate the light leakage strength and the presence or absence of peeling of the polarizing plate from the liquid crystal panel. .

Evaluation of light leakage was performed as follows.
Light leakage occurrence situation Practical problem Light leakage No occurrence None 1
Very weak None 2
Weak None 3
Strong Yes 4
Very strong Yes 5

It is explanatory drawing which measures the creep amount of the adhesive of this invention.

Explanation of symbols

70: Glass plate 80: Adhesive layer 90: Polarizing plate W: Load

Claims (19)

A polarizing plate having protective films on both sides of a polarizing film, wherein one of the protective films is a retardation plate having at least two optically anisotropic layers, and at least one of the optically anisotropic layers is a liquid crystal (Meta) having a Tg of less than −30 ° C. when the adhesive layer comprises (A) (a ₁ ) homopolymer, and has an adhesive layer on at least one surface of the polarizing plate. Acrylic acid ester monomer, (a ₂ ) a compound having a vinyl group with a Tg of −30 ° C. or higher when it is a homopolymer, and (a ₃ ) a functional group reactive to the polyfunctional compound (B) a-containing monomer consists of (meth) acrylic copolymer, in the mass ratio of the monomer units (meth) acrylic acid ester (a ₁₎ 75 parts by mass or more, a compound having a vinyl group (a ₂₎ is 25 parts by mass or less and a functional group Yes monomer (a ₃₎ is, the monomer (a ₁₎ and the compound copolymer 100 parts by weight is 10 parts by mass or less with respect to the sum 100 parts by weight of (a _2), and (B) a functional group-containing monomer ( a (meth) acrylic copolymer comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups in the molecule that can react with the functional group a ₃ ) to form a crosslinked structure. A polarizing plate, wherein a pressure-sensitive adhesive containing a polymer composition is applied and formed, and the gel fraction of the pressure-sensitive adhesive is 40% by mass or more and 90% by mass or less. A polarizing plate having protective films on both sides of a polarizing film, wherein one of the protective films is a retardation plate having at least two optically anisotropic layers, and at least one of the optically anisotropic layers is a liquid crystal A Tg of less than −30 ° C. when the pressure-sensitive adhesive layer comprises (A ₁ ) (a ₁₁ ) homopolymer. ) Acrylic acid ester monomer, (a ₁₂ ) a compound having a vinyl group having a Tg of −30 ° C. or higher when it is a homopolymer, and (a ₁₃ ) a functional group having reactivity with the polyfunctional compound (B). A (meth) acrylic copolymer comprising a group-containing monomer, wherein the (meth) acrylic acid ester (a ₁₁ ) is 75 parts by mass or more and the vinyl group-containing compound (a ₁₂ ) Is 25 parts by mass or less, and Functional group-containing monomer (a ₁₃₎ is, the monomer (a ₁₁₎ and the compound 10 parts by mass or less with respect to the sum 100 parts by weight of (a _12), copolymer 100 mass weight average molecular weight is 1,000,000 or more Part,
(A ₂ ) (a ₂₁ ) a (meth) acrylic acid ester monomer having a Tg of less than −30 ° C. when it is a homopolymer, and a vinyl group having a Tg of −30 ° C. or more when it is a homopolymer (a ₂₂ ) (Meth) acrylic copolymer comprising a compound and (a ₂₃ ) a functional group-containing monomer having reactivity with respect to the polyfunctional compound (B), wherein (meth) The acrylic ester (a ₂₁ ) is 75 parts by mass or more, the vinyl group-containing compound (a ₂₂ ) is 25 parts by mass or less, and the functional group-containing monomer (a ₂₃ ) comprises the monomer (a ₂₁ ) and 20 to 200 parts by mass of a copolymer having a mass average molecular weight of not more than 10 parts by mass and not more than 100,000 with respect to 100 parts by mass of the sum of the compounds (a ₂₂ ), and (B) a functional group-containing monomer (a ₁₃ ) and Reacts with the functional group of (a ₂₃ ) A pressure-sensitive adhesive containing a composition of a (meth) acrylic copolymer comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups capable of forming a bridge structure in the molecule. The adhesive has a gel fraction of 40% by mass or more and 90% by mass or less, and the functional group in the (meth) acrylic copolymers (A ₁ ) and (A ₂ ). A polarizing plate characterized in that the introduction amount of repeating units derived from the contained monomers (a ₁₃ ) and (a ₂₃ ) satisfies a functional group distribution rate of 0 to 15% by mass defined by the following formula (1) .
Formula (1): Functional group partition ratio = [mass of repeating unit derived from functional group-containing monomer (a ₂₃ ) in [(meth) acrylic copolymer (A ₂ ) / (meth) acrylic copolymer] The mass of the repeating unit derived from the functional group-containing monomer (a ₁₃ ) in (A ₁ )] × 100. _3. The glass transition temperature of the (meth) acrylic copolymer (A), (A ₁ ), or (A ₂ ) in the adhesive layer is 0 ° C. or less, 3 or 3. Polarizing plate.   The protective film on the side opposite to the side having at least two optically anisotropic layers of the polarizing film is a retardation plate having an optically anisotropic layer. The polarizing plate as described in.   The protective film on the side opposite to the side having at least two optically anisotropic layers of the polarizing film is a retardation plate comprising an optically anisotropic layer containing at least one liquid crystalline compound. The polarizing plate according to claim 1.   The adhesive layer is bonded to an alkali-free glass plate with an area of 10 mm in width and 10 mm in length, and a creep amount after applying a load of 200 g in an atmosphere at 25 ° C. for 1 hour is less than 40 μm. Item 6. The polarizing plate according to any one of Items 1 to 5.   The polarizing plate according to any one of claims 1 to 6, wherein a 90 ° peel adhesive strength in an atmosphere of 25 ° C to the alkali-free glass plate of the adhesive layer is 10 N / 25 mm width or more.   90 ° peel adhesion after treatment for 5 hours in an atmosphere of 70 ° C. with respect to the alkali-free glass plate of the adhesive layer is 10 N / 25 mm width or more at any measurement temperature of 0 to 90 ° C. The polarizing plate in any one of Claims 1-7.   The polarizing plate according to claim 1, wherein the adhesive layer has an elastic modulus at 25 ° C. of 0.08 MPa or more.   The polarizing plate according to claim 1, wherein the adhesive layer has an elastic modulus at 90 ° C. of 0.06 MPa or more.   The polarizing plate according to claim 1, wherein the adhesive layer has a shear elastic modulus of 0.1 GPa to 100 GPa.   12. The polarizing plate according to claim 1, wherein the pressure-sensitive adhesive has a gel fraction of 60% by mass or more and 90% by mass or less.   The polarizing plate according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 5 to 30 μm. The polarizing plate according to claim 1, wherein Nz is smaller than 0 when Nz of the retardation plate is defined as in the following formula (2).
Formula (2): Nz = 0.5 + Rth / Re
Here, Re and Rth represent an in-plane retardation value of the retardation plate and a retardation value in the thickness direction.   The optically anisotropic layer has a first optically anisotropic layer containing a discotic liquid crystalline compound and a second optically anisotropic layer containing a rod-like liquid crystalline compound, and the discotic liquid crystalline The alignment state is fixed so that the disc surface of the compound is substantially perpendicular to the surface of the first optically anisotropic layer, and the major axis direction of the rod-like liquid crystalline compound is the second optically different direction. The polarizing plate according to claim 1, wherein the orientation state is fixed so as to be substantially perpendicular to the plane of the isotropic layer. A polarizing plate having protective films on both sides of a polarizing film, the retardation film having an optically anisotropic layer containing at least one liquid crystalline compound on one side of the protective film, the optically anisotropic layer Contains a discotic liquid crystalline compound, and the orientation state is fixed so that the disc surface of the discotic liquid crystalline compound is substantially perpendicular to the surface of the optically anisotropic layer. A (meth) acrylic acid ester monomer having a Tg of less than −30 ° C. when the pressure-sensitive adhesive layer is at least one surface and the pressure-sensitive adhesive layer is (A) (a ₁ ) homopolymer, and (a ₂ ) a homopolymer A (meth) acrylic copolymer comprising a compound having a vinyl group having a Tg of −30 ° C. or higher, and a functional group-containing monomer having reactivity to the polyfunctional compound (B) (a ₃ ) In terms of mass ratio of monomer units Meth) acrylic acid ester (a ₁₎ 75 parts by mass or more, there is a compound having a vinyl group (a ₂₎ is less than 25 parts by weight, and functional group-containing monomer (a ₃₎ is, the monomer (a ₁ ) And 100 parts by mass of the sum of the compound (a ₂ ) and 100 parts by mass of the copolymer, and (B) the functional group of the functional group-containing monomer (a ₃ ) to react with the functional group. A pressure-sensitive adhesive containing a composition of (meth) acrylic copolymer comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups capable of forming And a gel fraction of the pressure-sensitive adhesive is 40% by mass or more and 90% by mass or less. A polarizing plate having protective films on both sides of a polarizing film, the retardation film having an optically anisotropic layer containing at least one liquid crystalline compound on one side of the protective film, the optically anisotropic layer Contains a discotic liquid crystalline compound, and the orientation state is fixed so that the disc surface of the discotic liquid crystalline compound is substantially perpendicular to the surface of the optically anisotropic layer. A (meth) acrylic acid ester monomer having an adhesive layer on at least one side and having a Tg of less than −30 ° C. when the adhesive layer is (A ₁ ) (a ₁₁ ) homopolymer, and (a ₁₂ ) homopolymer (Meth) acrylic copolymer comprising a compound having a vinyl group having a Tg of −30 ° C. or more and (a ₁₃ ) a functional group-containing monomer having reactivity with the polyfunctional compound (B) Where the mass of monomer units In In (meth) acrylic acid ester (a ₁₁₎ is 75 parts by mass or more, there is a compound having a vinyl group (a ₁₂₎ is less than 25 parts by weight, and functional group-containing monomer (a ₁₃₎ is, the monomer ( 100 parts by mass of a copolymer having a mass average molecular weight of 1 million or more, based on 100 parts by mass of the sum of a ₁₁ ) and compound (a ₁₂ ),
(A ₂ ) (a ₂₁ ) a (meth) acrylic acid ester monomer having a Tg of less than −30 ° C. when it is a homopolymer, and a vinyl group having a Tg of −30 ° C. or more when it is a homopolymer (a ₂₂ ) (Meth) acrylic copolymer comprising a compound and (a ₂₃ ) a functional group-containing monomer having reactivity with respect to the polyfunctional compound (B), wherein (meth) The acrylic ester (a ₂₁ ) is 75 parts by mass or more, the vinyl group-containing compound (a ₂₂ ) is 25 parts by mass or less, and the functional group-containing monomer (a ₂₃ ) comprises the monomer (a ₂₁ ) and 20 to 200 parts by mass of a copolymer having a mass average molecular weight of not more than 10 parts by mass and not more than 100,000 with respect to 100 parts by mass of the sum of the compounds (a ₂₂ ), and (B) a functional group-containing monomer (a ₁₃ ) and Reacts with the functional group of (a ₂₃ ) A pressure-sensitive adhesive containing a composition of a (meth) acrylic copolymer comprising 0.01 to 1.5 parts by mass of a polyfunctional compound having at least two functional groups capable of forming a bridge structure in the molecule. The adhesive has a gel fraction of 40% by mass or more and 90% by mass or less, and the functional group in the (meth) acrylic copolymers (A ₁ ) and (A ₂ ). A polarizing plate characterized in that the introduction amount of repeating units derived from the contained monomers (a ₁₃ ) and (a ₂₃ ) satisfies a functional group distribution rate of 0 to 15% by mass defined by the following formula (1) .
Formula (1): Functional group partition ratio = [mass of repeating unit derived from functional group-containing monomer (a ₂₃ ) in [(meth) acrylic copolymer (A ₂ ) / (meth) acrylic copolymer] The mass of the repeating unit derived from the functional group-containing monomer (a ₁₃ ) in (A ₁ )] × 100. 18. The glass transition temperature of the (meth) acrylic copolymer (A), (A ₁ ), or (A ₂ ) in the adhesive layer is 0 ° C. or less, 18 or 17, Polarizing plate.   The liquid crystal display device containing the polarizing plate of any one of Claims 1-18, and a liquid crystal cell.

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