WO2011024683A1 - Optical compensation film, polarizing plate, and liquid crystal display device - Google Patents

Optical compensation film, polarizing plate, and liquid crystal display device Download PDF

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Publication number
WO2011024683A1
WO2011024683A1 PCT/JP2010/063915 JP2010063915W WO2011024683A1 WO 2011024683 A1 WO2011024683 A1 WO 2011024683A1 JP 2010063915 W JP2010063915 W JP 2010063915W WO 2011024683 A1 WO2011024683 A1 WO 2011024683A1
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Prior art keywords
liquid crystal
layer
optical compensation
compensation film
film
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PCT/JP2010/063915
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French (fr)
Japanese (ja)
Inventor
山本　智弘
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コニカミノルタオプト株式会社
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Priority to JP2011528750A priority Critical patent/JPWO2011024683A1/en
Publication of WO2011024683A1 publication Critical patent/WO2011024683A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3016—Polarising elements involving passive liquid crystal elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
    • C08J2301/08—Cellulose derivatives
    • C08J2301/10—Esters of organic acids
    • C08J2301/12—Cellulose acetate
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133633—Birefringent elements, e.g. for optical compensation using mesogenic materials

Definitions

  • the present invention relates to an optical compensation film, a polarizing plate, and a liquid crystal display device.
  • an optical film having optical compensation performance is used in order to improve optical characteristics such as viewing angle characteristics.
  • an optical compensation film an optical compensation film containing an optical anisotropic layer containing a liquid crystal compound and having the liquid crystal compound aligned is known.
  • the back coat layer is preferably applied also as an anti-blocking layer, and therefore fine particles for imparting an anti-blocking function are added to the coating composition for forming the back coat layer.
  • optical compensation film examples include those described in Patent Documents 1 to 3 below.
  • Patent Document 1 describes a coating composition useful for producing an optically anisotropic layer containing a liquid crystal compound that contributes to optical compensation of a liquid crystal display device while maintaining stable and good planar smoothness. Has been. Patent Document 1 describes that a backcoat layer is provided on the surface of the optical compensation film opposite to the optically anisotropic layer.
  • Patent Documents 2 and 3 include an optical compensation film having a functional thin film layer on one side of a transparent film substrate and a backcoat layer containing cellulose ester, fine particles and an organic solvent as constituent components on the opposite side. Are listed.
  • an optical compensation film that requires surface smoothness such as a liquid crystal coated film
  • a hard coat layer (anti-blocking layer) on the side opposite to the surface on the optically anisotropic layer side containing a liquid crystal compound is manufactured. This is an important process issue.
  • blocking sticking in a wound state, deformation
  • the transparent film base material and the optical anisotropic layer (liquid crystal layer) are deformed, and retardation unevenness (unevenness due to optical value fluctuation)
  • the object of the present invention is to solve the above-mentioned problems of the prior art, wherein an optically anisotropic layer (liquid crystal layer) is provided on one side of a transparent film substrate made of a cellulose resin film, and fine particles are provided on the other side. Retardation unevenness due to deformation of optically anisotropic layer (liquid crystal layer) containing transparent film base material and liquid crystal compound due to improvement of blocking (adhesion) for optical compensation film provided with back coat layer containing binder An optical compensation film having excellent surface smoothness (low haze), a polarizing plate using the same, and a liquid crystal display device are provided.
  • the present inventor has provided an optically anisotropic layer (liquid crystal layer) containing a liquid crystal compound on one side of a transparent film substrate made of a cellulose resin film.
  • the optical compensation film provided with a backcoat layer containing fine particles and a binder on the other side has been found to have a reduced blocking effect if the surface roughness of the region where the fine particles are not present on the backcoat layer base layer surface is small. It was. Then, when forming the backcoat layer, the surface roughness of the region where fine particles on the surface of the backcoat layer base layer are not present is determined by selecting a solvent type in the coating composition for forming the backcoat layer.
  • the thickness of the optical compensation film By controlling the thickness of the optical compensation film, it is possible to improve the blocking (adhesion) of the optical compensation film, thereby reducing retardation unevenness due to deformation of the optically anisotropic layer (liquid crystal layer) containing the transparent film substrate and the liquid crystal compound. It has been found that it can be suppressed, and the present invention has been completed.
  • an optical compensation film according to claim 1 is provided with an optically anisotropic layer containing an aligned liquid crystal compound on one side of a cellulose ester resin transparent film substrate.
  • the particle size of the fine particles contained in the back coat layer is 1 ⁇ m or less
  • the center line average roughness (Ra) of the region where fine particles are not present on the back coat layer base layer surface is in the range of 2 to 10 nm.
  • the invention according to claim 2 is the optical compensation film according to claim 1, wherein a bonding intermediate layer is provided between one side of the transparent film substrate and the optically anisotropic layer containing the liquid crystal compound. It is characterized by having.
  • the invention of claim 3 is the optical compensation film of claim 1 or 2, wherein the cellulose ester resin transparent film substrate is a cellulose acetate propionate film.
  • the invention of claim 4 is a polarizing plate having the optical compensation film according to any one of claims 1 to 3.
  • the invention of claim 5 is a liquid crystal display device having the polarizing plate of claim 4.
  • an optically anisotropic layer containing an oriented liquid crystal compound is provided on one side of a cellulose ester resin transparent film base, and the other side of the transparent film base is provided.
  • the fine particles contained in the back coat layer have a particle size of 1 ⁇ m or less, and the presence of fine particles on the surface of the back coat layer base layer.
  • the center line average roughness (Ra) of the region not to be removed is in the range of 2 to 10 nm.
  • the invention according to claim 2 is the optical compensation film according to claim 1, wherein a bonding intermediate layer is provided between one side of the transparent film substrate and the optically anisotropic layer containing the liquid crystal compound. Therefore, according to the invention of claim 2, the occurrence of defects in the bonding intermediate layer and the optically anisotropic layer can be suppressed, and the adhesion between the bonding intermediate layer and the optically anisotropic layer is sufficiently high. Furthermore, there is an effect that an optical compensation film having a sufficiently high orientation of the liquid crystal compound of the optically anisotropic layer can be obtained.
  • the cellulose ester resin transparent film substrate is preferably a cellulose acetate propionate film from the viewpoint of high transparency.
  • Invention of Claim 4 is a polarizing plate which has an optical compensation film of any one of Claim 1 to 3, According to invention of Claim 4, as a transparent protective film of a polarizing plate, optical compensation performance For example, when applied to a liquid crystal display device, a polarizing plate that can realize high image quality of the liquid crystal display device, such as widening of the viewing angle and improvement of contrast, can be obtained. .
  • the invention of claim 5 is a liquid crystal display device having the polarizing plate of claim 4, and according to the invention of claim 5, a polarizing plate comprising an optical compensation film excellent in optical compensation performance is used.
  • a high-quality liquid crystal display device with improved viewing angle, contrast, and the like can be provided.
  • optical compensation film The optical compensation film according to the present invention is provided with an optically anisotropic layer containing an oriented liquid crystal compound on one side of a cellulose ester-based resin transparent film base, and on the other side of the transparent film base.
  • An optical compensation film provided with a backcoat layer containing a resin binder and fine particles, wherein the particle size of the fine particles contained in the backcoat layer is 1 ⁇ m or less, and no fine particles are present on the surface of the backcoat layer base layer.
  • the center line average roughness (Ra) of the region is in the range of 2 to 10 nm.
  • the optical compensation film according to the present invention comprises a transparent film substrate and a functional layer formed on the transparent film substrate, and the functional layer contains an actinic radiation curable resin and a bonding intermediate layer.
  • the optically anisotropic layer containing a liquid crystal compound is laminated, and a bonding intermediate layer is present closer to the transparent film substrate than the optically anisotropic layer.
  • the optical compensation film is not limited to a functional layer composed of only a bonding intermediate layer and an optically anisotropic layer, and may include other layers.
  • an underlayer may be provided as a functional layer as a second intermediate layer interposed between the transparent film substrate and the bonding intermediate layer.
  • the base layer include those that function as an antistatic layer, an elution suppression layer, an antiglare layer, and the like.
  • a back coat layer is provided on the surface of the cellulose ester resin transparent film substrate opposite to the surface on which the optically anisotropic layer is provided.
  • the back coat layer is provided to correct curling caused by providing the active energy ray-curable resin layer and other layers, and the back coat layer is also provided as an anti-blocking layer. Fine particles are added to the layer coating composition in order to provide an anti-blocking function.
  • the particle size of the fine particles contained in the backcoat layer is 1 ⁇ m or less.
  • the particle size of the fine particles contained in the backcoat layer exceeds 1 ⁇ m, the haze of the optical compensation film is increased, the possibility of fine particles falling off is increased, and there is a concern about process contamination.
  • the center line average roughness (Ra) of the region where the fine particles are not present on the surface of the backcoat layer base layer is in the range of 2 to 10 nm.
  • the center line average roughness (Ra) of the base layer surface of the back coat layer of the optical compensation film according to the present invention is, for example, a three-dimensional surface structure analysis microscope (zygo New View) under conditions of a temperature of 23 ° C. and a humidity of 50 ⁇ 5% RH. 5000, manufactured by Canon Sales Co., Ltd.) and can be measured with an objective lens 50 times and an image zoom 1.0 times.
  • the center line average roughness (Ra) is measured for the surface of the backcoat layer base layer, which is a region portion (hereinafter referred to as a region portion where no fine particles are present) cut from the fine particle existence region portion having a peak of 50 nm or more. It is.
  • the center line average roughness (Ra) of the region where the fine particles are not present on the back coat layer base layer surface is as small as less than 2 nm, the effect of improving blocking is reduced, which is not preferable.
  • fine-particles of the backcoat layer base layer do not exist exceeds 10 nm, the surface smoothness of an optical compensation film is inferior, haze becomes high, and transparency deteriorates. Therefore, it is not preferable.
  • the inventor has developed a composition for forming a backcoat layer by mixing a solvent having a high solubility and a low solubility in various proportions with respect to the transparent film substrate component of the optical compensation film. It has been found that the target surface roughness can be obtained from the difference in the degree of swelling of the substrate by using it as a solvent for the product.
  • the transparent film substrate is not particularly limited as long as it is transparent and can be used as a substrate for an optical compensation film.
  • being transparent means that the transmittance of visible light is 60% or more, preferably 80% or more, and more preferably 90% or more.
  • Specific examples of the transparent film substrate include a resin film containing a transparent resin.
  • the transparent resin is not particularly limited as long as it can be used as the base material of the optical compensation film.
  • the transparent resin has transparency when formed into a film base material.
  • Specific examples of the transparent resin include cellulose ester resins.
  • the cellulose ester resin is not particularly limited. Specifically, for example, a carboxylic acid ester having about 2 to 22 carbon atoms is preferable, and a lower fatty acid ester having 2 to 6 carbon atoms is more preferable. Moreover, ester of aromatic carboxylic acid may be sufficient.
  • cellulose ester resin more specifically, for example, in addition to acetyl groups such as cellulose acetate propionate resin, cellulose acetate butyrate resin, and cellulose acetate propionate butyrate resin, propionate groups or Examples thereof include mixed fatty acid esters of cellulose to which butyrate groups are bonded.
  • a cellulose acetate propionate resin containing a propionate group as a substituent is particularly useful as a film for a liquid crystal image display device because of its excellent water resistance and high transparency.
  • the cellulose ester resin for example, when the substitution degree of acetyl group is X, the substitution degree of propionyl group or butyryl group is Y, and the total acyl group substitution degree is X + Y, X and Y are A cellulose ester resin having a mixed fatty acid ester of cellulose satisfying the following formulas (I) and (II) is preferable.
  • the portion not substituted with an acyl group usually exists as a hydroxyl group.
  • These cellulose ester resins can be synthesized by a known method. The method for measuring the substitution degree of the acyl group can be measured in accordance with the provisions of ASTM-D817-96.
  • the acyl group may be linear or branched, or may form a ring.
  • substitution degree of the acyl group is the same, birefringence decreases when the carbon number of the acyl group is large, and therefore an acyl group having 2 to 6 carbon atoms is preferable.
  • the butyryl group forming butyrate may be linear or branched.
  • the cellulose ester resin a single cellulose ester resin may be used, or a plurality of cellulose ester resins, for example, those having different degrees of acyl group substitution may be used in combination. .
  • a transparent film substrate having desired optical properties can be obtained.
  • the mixing ratio between the cellulose ester resin within the preferred range and the cellulose ester resin outside the preferred range is 100: 0 by mass ratio. Preferably it is ⁇ 50: 50.
  • the cellulose that is a raw material of the cellulose ester resin is not particularly limited, and examples thereof include cotton linters, wood pulp (derived from coniferous trees and hardwoods), kenaf and the like. Moreover, the cellulose ester-type resin obtained from them can be mixed and used in arbitrary ratios, respectively.
  • the acylating agent is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride)
  • these cellulose ester resins use an organic acid such as acetic acid or an organic solvent such as methylene chloride, It can be obtained by reacting with a cellulose raw material using such a protic catalyst.
  • the number average molecular weight of the cellulose ester-based resin is preferably 60000 to 300000 from the viewpoint of strong mechanical strength when molded into an optical compensation film. Moreover, it is preferable also from the point which becomes moderate dope viscosity in a solution casting film forming method. Further, it is more preferably 70000-200000.
  • the weight average molecular weight (Mw) / number average molecular weight (Mn) is preferably in the range of 1.4 to 4.5.
  • the weight average molecular weight Mw and the number average molecular weight Mn of the cellulose ester-based resin were measured using gel permeation chromatography (GPC).
  • the cellulose ester-based resin may be used alone or in combination of two or more.
  • the cellulose ester resin can be produced by a known method. Specifically, when the acylating agent is an acid chloride (CH 3 COCl, C 2 H 5 COCl, C 3 H 7 COCl), the reaction is performed using a basic compound such as an amine as a catalyst. Is called. More specifically, it can be synthesized with reference to the method described in JP-A-10-45804.
  • the cellulose ester-based resin is obtained by adjusting the amount of the acylating agent in accordance with the degree of substitution, and the cellulose ester-based resin reacts with the hydroxyl group of the cellulose molecule.
  • Cellulose molecules are composed of many glucose units linked together, and the glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution (mol%).
  • cellulose triacetate has acetyl groups bonded to all three hydroxyl groups of the glucose unit (actually 2.6 to 3.0).
  • a cellulose ester film As a cellulose ester film, what is marketed, specifically, for example, Konica Minolta Op KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC12UR, manufactured by Konica Minolta Opto Co., Ltd.
  • the transparent film base material it is preferable to perform a surface treatment before forming the bonding intermediate layer.
  • the surface treatment is not particularly limited, and a normal method can be employed. Specific examples include glow discharge treatment, corona discharge treatment, ultraviolet treatment, flame treatment, and the like.
  • the transparent film substrate is preferably an optically biaxial film.
  • the optically biaxial film is a transparent film substrate that satisfies nx>ny> nz.
  • the optically biaxial film has a visible light transmittance of 80% or more, a film thickness of 20 to 70 ⁇ m, an in-plane retardation (Ro) determined by the following formula (1) of 20 to 330 nm, and the following formula ( The thickness direction retardation (Rt) obtained in 2) is preferably 50 to 340 nm.
  • nx represents the refractive index in the slow axis direction in the plane of the film
  • ny represents the refractive index in the direction perpendicular to the slow axis in the plane of the film
  • nz represents the thickness direction of the film.
  • Refractive index is shown
  • d shows the thickness (nm) of a film.
  • Each refractive index can be measured at a wavelength of 590 nm in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH using, for example, KOBRA-21ADH manufactured by Oji Scientific Instruments.
  • a retardation increasing agent an acrylic polymer, and a sugar ester compound.
  • the retardation increasing agent is not particularly limited as long as it increases the retardation of the cellulose ester film.
  • a transparent film substrate when a transparent film substrate is produced, it may contain fine particles, a plasticizer, and an ultraviolet absorber as long as it does not inhibit the curing of the resin composition that is the raw material. Moreover, the detail about the manufacturing method of such a transparent film base material (resin film) is mentioned later.
  • the thickness of the transparent film substrate is preferably thinner in order to achieve a thinner resin film, but is preferably 20 ⁇ m or more in order to prevent breakage during production.
  • the thickness here means the average film thickness.
  • the thickness is measured at 20 to 200 locations in the width direction of the film with a contact-type film thickness meter manufactured by Mitutoyo Corporation, and the average value of the measured values is calculated. Shown as film thickness.
  • the width, physical properties, and shape of the transparent film substrate are not particularly limited and can be appropriately selected according to the purpose of the optical compensation film to be manufactured. From the viewpoint of use in a large-sized liquid crystal display device, use efficiency of a film during polarizing plate processing, and production efficiency, the thickness is preferably 1000 to 4000 mm.
  • the transparent film substrate is not particularly limited as long as it can be used as a substrate for an optical compensation film.
  • a resin film obtained by a solution casting film forming method or a melt casting film forming method can be used. If it is such a resin film, a film thickness is uniform and it can be conveniently used as a base material of an optical compensation film.
  • the cellulose ester resin transparent film substrate is preferably a cellulose acetate propionate resin film. According to such a configuration, since the transparency of the transparent film substrate is high, and the orientation of the liquid crystal compound contained in the optical anisotropic layer is high, not only the optical compensation performance is excellent, but also the transparency. In addition, a sufficiently excellent optical compensation film can be obtained.
  • the optically anisotropic layer is not particularly limited as long as it contains a liquid crystal compound, and examples thereof include an optically anisotropic layer that can exhibit predetermined optical compensation performance such as widening the viewing angle. In the optically anisotropic layer, the liquid crystal compound is preferably aligned, and the alignment property is more preferable.
  • the liquid crystal compound is not particularly limited, and examples thereof include conventionally known liquid crystal compounds contained in the optically anisotropic layer. Specifically, for example, those having a rod-like mesogen group or a disk-like mesogen group in the molecule can be mentioned. Among these, those having a rod-like mesogenic group in the molecule are preferable.
  • the liquid crystal compound is more preferably a liquid crystal compound having so-called vertical alignment, which can be vertically aligned and the alignment can be fixed. That is, the optically anisotropic layer contains, for example, a liquid crystal compound having a rod-shaped mesogenic group in the molecule, and the mesogenic group has a major axis direction substantially perpendicular to the surface direction of the transparent film substrate. It is preferable that the orientation is fixed after being oriented (vertical orientation).
  • the liquid crystal compound has a rod-shaped mesogenic group in the molecule, and the orientation is fixed after the mesogenic group is oriented so that its major axis direction is substantially perpendicular to the surface direction of the transparent film substrate. It is preferable that According to such a configuration, an optical film having better optical compensation performance can be obtained.
  • the liquid crystal compound having a rod-shaped mesogen group in the molecule may be a polymerizable liquid crystal containing a rod-shaped mesogen group and a polymerizable functional group, and at least one of the main chain and the side chain. It may be a polymer liquid crystal containing a rod-shaped mesogen group or a polymer liquid crystal containing a rod-shaped mesogen group and a polymerizable functional group.
  • the alignment can be further fixed by, for example, cooling to a temperature lower than the liquid crystal transition temperature and then polymerizing while cooling. From the point etc. which can be hardened as an adhesive layer.
  • a polymerizable liquid crystal is preferable.
  • the mesogenic group is not particularly limited, but is preferably a rod-shaped mesogenic group that can be vertically aligned. Specific examples include functional groups containing an ester group, a cyano group, an alkyl group, and an aryl group. Moreover, as a mesogenic group, the said mesogenic group may be contained 1 type, and it may contain in combination of 2 or more types.
  • the polymerizable functional group is not particularly limited, and it is preferable that polymerization can be performed while maintaining the orientation after the orientation.
  • the polymerization may be initiated by heat, or the polymerization may be initiated by irradiation with active rays such as ultraviolet rays. That is, in the case of the polymerizable liquid crystal, it may be thermosetting or actinic ray curable.
  • active rays such as ultraviolet rays.
  • the liquid crystal compound is polymerized at a temperature lower than the liquid crystal transition temperature, it is preferable that the liquid crystal compound is not heated so much that the active ray curable one is more preferable.
  • the liquid crystal compound is a polymerizable liquid crystal compound having a functional group that can be polymerized by irradiation with actinic radiation, and the immobilization step cools the coating composition for forming the optical anisotropic layer, and then the optical anisotropy.
  • the layer forming coating composition is preferably a step of irradiating an active ray to cure the optically anisotropic layer forming coating composition.
  • the polymerizable functional group examples include a vinyl group such as acryloyl group, methacryloyl group and vinyl ether, an epoxy group, and an oxetanyl group.
  • a polymerizable functional group may be used independently and may be used in combination of 2 or more type.
  • the polymerizable liquid crystal may contain one polymerizable functional group in the molecule, or may contain two or more.
  • liquid crystal compound examples include those containing a mesogenic group and those containing a mesogenic group and a polymerizable functional group. Specifically, for example, Makromol. Chem. 190, 2255 (1989), Advanced Materials, 5, 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, International Publication No. No.
  • R 1 and R 2 each independently represent hydrogen or a methyl group
  • X represents hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, or a nitro group.
  • a and b are 2 to 12.
  • R 3 represents hydrogen or a methyl group.
  • R 1 and R 2 both represent hydrogen from the viewpoint of a wide temperature range indicating a liquid crystal phase.
  • X is preferably a chlorine or methyl group.
  • a and b each represent 2 to 12, preferably 4 to 10, and more preferably 6 to 9.
  • liquid crystal compound the above liquid crystal compounds may be used alone or in combination of two or more.
  • liquid crystal compound as a commercially available product, specifically, for example, UCL018 manufactured by DIC Corporation, Paliocolor LC242 manufactured by BASF Corporation, and the like can be given.
  • the vertical alignment means that the tilt angle, which is the angle of the major axis direction of the mesogenic group (the alignment direction of the liquid crystal compound) with respect to the thickness direction of the transparent film substrate, is 70 to 90 °. 80 to 90 ° is preferable. Further, it is known that whether or not the liquid crystal compound is vertically aligned depends on the structure of the liquid crystal compound, particularly its rod-shaped mesogen group. That is, a liquid crystal compound having a vertically aligned structure can be vertically aligned by a known alignment process.
  • a coating composition (coating liquid) for forming an optically anisotropic layer containing a liquid crystal compound, which is applied on a bonding intermediate layer or the like which is a coating layer is applied to a liquid crystal.
  • a method of fixing the vertical alignment by heating the compound to a liquid crystal transition temperature or higher to cause vertical alignment and then cooling to a temperature lower than the liquid crystal transition temperature.
  • the liquid crystal transition temperature refers to a solid-liquid crystal phase transition temperature.
  • the heating up to the liquid crystal transition temperature or higher after coating the coating composition for forming an optically anisotropic layer is preferably up to the liquid crystal-isotropic liquid phase transition temperature or lower.
  • the thickness of the optically anisotropic layer is preferably 0.1 to 10 ⁇ m, and more preferably 0.2 to 5 ⁇ m.
  • the optically anisotropic layer preferably has an in-plane retardation (Ro) determined by the above formula (1) of 0 to 10 nm. Further, the thickness direction retardation (Rt) determined by the above formula (2) is preferably ⁇ 500 to ⁇ 100 nm.
  • the bonding intermediate layer is formed on the transparent film base material or on the base layer when the base layer is provided.
  • the bonding intermediate layer includes an actinic radiation curable resin. Further, the bonding intermediate layer may function as a liquid crystal alignment layer that promotes alignment of the liquid crystal compound of the optically anisotropic layer, specifically, for example, a layer subjected to rubbing treatment.
  • the actinic radiation curable resin is curable by actinic radiation such as ultraviolet rays and has transparency.
  • having transparency means that the transmittance of visible light is 60% or more, preferably 80% or more, and more preferably 90% or more.
  • Specific examples include those having a polymerizable functional group such as a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, an isopropenyl group, an epoxy group, and an oxetanyl group.
  • actinic radiation curable resin what has two or more polymeric functional groups and becomes a crosslinked structure or network structure by irradiating actinic radiation is preferable.
  • the active ray is preferably ultraviolet rays from the viewpoint of workability.
  • the actinic radiation curable resin is preferably an ultraviolet curable resin.
  • the actinic radiation curable resin is preferably obtained by curing an actinic radiation curable compound.
  • the actinic radiation curable compound is more preferably at least one of a urethane acrylate oligomer and an acrylate oligomer.
  • the actinic radiation curable resin include an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable resin.
  • ultraviolet curable acrylate resins such as epoxy resins.
  • ultraviolet curable urethane acrylate resin examples include, for example, products obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate (
  • acrylates include those containing methacrylates, and only those acrylates are indicated), and those that can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. More specifically, examples include those described in JP-A No. 59-151110.
  • UV curable polyester acrylate resin examples include those that can be easily obtained by reacting polyester polyol with 2-hydroxyethyl acrylate or 2-hydroxy acrylate acrylate monomer. Can be mentioned. More specifically, examples include those described in JP-A-59-151112.
  • ultraviolet curable epoxy acrylate resin examples include those produced by reacting an epoxy acrylate with an oligomer, a reactive diluent and a photopolymerization initiator added thereto. More specifically, examples include those described in JP-A-1-105738.
  • ultraviolet curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and alkyl-modified dipentaerythritol. Examples include pentaacrylate.
  • the active ray curable resin includes methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate. 1,4-cyclohexyldimethyladiacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylic ester, and the like.
  • Adekaoptomer KR / BY series KR-400, KR-410, KR-550, KR-566, KR-567, BY, manufactured by ADEKA Corporation.
  • -320B KOHEI HARD A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T -102, D-102, NS-101, FT-102Q8, MAG-1-P20, AG-106, M-101-C, Seika Beam PHC2210 (S), PHCX-9 (manufactured by Dainichi Seika Kogyo Co., Ltd.) K-3), PHC2213, DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, CR900, manufactured by Daicel-Cytech Co., Ltd., KRM7033, KRM70
  • the thickness of the bonding intermediate layer is preferably 0.01 to 1 ⁇ m, and more preferably 0.02 to 0.7 ⁇ m. If the thickness of the bonding intermediate layer is too thin, the bonding intermediate layer has an effect such as a liquid crystal alignment layer, an antistatic layer, an elution preventing layer, an antiglare layer, or the like, and the above-described adhesion is enhanced. There is a tendency that it becomes difficult to exert the effect. Moreover, when the thickness of the joining intermediate layer is too thick, the obtained optical compensation film becomes unnecessarily thick, and there is a tendency that the thinning of the optical compensation film is hindered.
  • the actinic radiation curable resin is preferably obtained by curing an actinic radiation curable compound.
  • the actinic radiation curable compound is more preferably at least one of a urethane acrylate oligomer and an acrylate oligomer.
  • the backcoat layer is provided in the surface on the opposite side to the surface in which the optically anisotropic layer was provided of the cellulose-ester-type resin transparent film base material.
  • the back coat layer is also applied as an anti-blocking layer, and in this case, fine particles are added to the coating composition for forming the back coat layer in order to provide an anti-blocking function.
  • the back coat layer is also provided for correcting curling caused by providing the active energy ray-curable resin layer and other layers. That is, the degree of curling can be balanced by giving the optical compensation film the property of being rounded with the surface on which the backcoat layer is provided inside.
  • examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, Mention may be made of indium oxide, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low haze, and silicon dioxide is particularly preferable.
  • These fine particles are, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above, manufactured by Nippon Aerosil Co., Ltd.), Seahoster KE-P10, KE-P30, KE-P50. KE-P100, KE-P150, and KE-P250 (above, manufactured by Nippon Shokubai Co., Ltd.) can be used. Among these, particularly preferred are Seahoster KE-P30, KE-P50, and KE-P100.
  • Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.), and can be used.
  • polymer fine particles examples include acrylic resin fine particles, silicone resin fine particles, and fluororesin fine particles.
  • the acrylic resin fine particles are commercially available under the trade names of MP-1451 (manufactured by Soken Chemical Co., Ltd.) and Riosphere RSP-3021D (manufactured by Toyo Ink Co., Ltd.), and can be used.
  • silicone resin fine particles those having a three-dimensional network structure are particularly preferable.
  • Tospearl 103, 105, 108, 120, 145, 3120 and 240 (above, manufactured by Toshiba Silicone Co., Ltd.) It is marketed under the trade name of and can be used.
  • the fine particles contained in the backcoat layer have a particle size of 1 ⁇ m or less.
  • the fine particles contained in the backcoat layer are 0.1 to 50% by mass, preferably 0.1 to 10% by mass, based on the binder.
  • the increase in haze is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.0 to 0.1%.
  • the particle size of the fine particles contained in the backcoat layer is more preferably 400 nm or less, which is the approximate lower limit of the visible light region. This is because scattering hardly occurs when the particle diameter is optically smaller than the wavelength.
  • Examples of the resin used as the binder of the back coat layer include cellulose acetate propionate (preferably acetyl group substitution degree 1.2 to 2.3, propionyl group substitution degree 0.1 to 1.0), diacetyl cellulose, cellulose Examples thereof include, but are not limited to, cellulose ester resins such as acetate butyrate resin.
  • cellulose resins such as diacetyl cellulose, triacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate.
  • the back coat layer is a coating for forming a back coat layer containing the fine particles, the binder, and a solvent that dissolves or swells the cellulose ester resin transparent film substrate, and a solvent that does not dissolve the film substrate.
  • the composition is performed by applying a cellulose ester resin transparent film substrate to the composition.
  • the coating composition for forming the backcoat layer it is preferable to use two kinds of mixed solvents for the coating composition for forming the backcoat layer.
  • solvent having an SP value of 9 to 10 is “solvent 1” and the solvent having an SP value of 11 to 15 is “solvent 2”, these solvents satisfy the following two conditions.
  • condition 1 Boiling point of solvent 1> Boiling point of solvent 2
  • Condition 2 Mixing ratio of solvent 1 and solvent is 8: 2 to 1: 9
  • the SP value of an organic compound is a solubility parameter, which is a numerical value of how easily it is soluble in a solvent, etc., and is synonymous with the polarity often used in organic compounds. The greater the SP value, the greater the polarity.
  • the SP value a value calculated by the Fedors method can be used.
  • a solvent satisfying the above conditions can be appropriately selected.
  • alcohol solvents such as methanol (MA), ethanol (EA), 1-propanol (NPA), isopropanol (IPA), butanol, pentanol, benzyl alcohol, diacetone alcohol (DAA), acetone, acetylacetone, methyl ethyl ketone ( MEK), methyl propyl ketone, methyl isobutyl ketone (MIBK), ketone solvents such as cyclohexanone, isophorone, methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, amyl formate, isoamyl acetate, butyl propionate, isopropyl butyrate, ethyl butyrate Butyl butyrate, methyl lactate, ethy
  • the order of coating the backcoat layer may be before or after coating the active energy ray-curable resin layer of the cellulose ester-based resin transparent film substrate. However, if the backcoat layer also serves as an antiblocking layer, It is desirable to apply to. Alternatively, the backcoat layer can be applied in two or more steps. (Method for producing optical compensation film) Specifically, the optical compensation film according to the present invention is manufactured as follows.
  • the back coat layer since the back coat layer also serves as an anti-blocking layer, the back coat layer is first coated on one side of the cellulose ester resin transparent film substrate, and then the transparent film. It is desirable to coat an active ray curable resin layer, which is a bonding intermediate layer, on the other surface of the substrate.
  • the backcoat layer is a coating composition for forming a backcoat layer containing fine particles, a binder, a solvent that dissolves the cellulose ester-based resin transparent film substrate or a solvent that swells, and a solvent that does not dissolve the film substrate. This is done by applying the product onto the surface of the cellulose ester resin transparent film substrate.
  • the coating is preferably performed with a thickness of 1 to 100 ⁇ m, particularly preferably 5 to 30 ⁇ m.
  • the order of coating the backcoat layer may be before or after coating the active energy ray-curable resin layer of the cellulose ester-based resin transparent film substrate. However, if the backcoat layer also serves as an antiblocking layer, It is desirable to apply to. Alternatively, the backcoat layer can be applied in two or more steps.
  • an intermediate layer for bonding is formed on the transparent film substrate.
  • a coating composition for forming an intermediate layer containing an actinic radiation curable resin is applied onto a transparent film substrate.
  • the coating method is not particularly limited, and a known coating method can be used. Specific examples include a gravure coater, a spinner coater, a wire bar coater, a roll coater, a reverse coater, an extrusion coater, an air doctor coater, a die coater, a dip coater, and an ink jet method.
  • the coating thickness varies depending on the solid content concentration of the coating composition for forming an intermediate layer, but specifically, for example, a thickness such that the thickness of the formed bonding intermediate layer is within the above range.
  • the wet film thickness is preferably 0.1 to 40 ⁇ m, and more preferably 0.5 to 30 ⁇ m.
  • the dry film thickness is preferably 0.01 to 1 ⁇ m in average film thickness, and more preferably 0.02 to 0.7 ⁇ m.
  • the intermediate layer-forming coating composition coated on the transparent film substrate is irradiated with actinic rays to form a bonding intermediate layer.
  • middle layer formation apply
  • the drying method is not particularly limited as long as the organic solvent in the coating composition for forming an intermediate layer can be dried. Specific examples include air drying, heat removal, and reduced pressure removal. These may be performed alone or in combination of two or more.
  • the actinic radiation is not particularly limited as long as the intermediate layer forming coating composition can be cured, and specific examples thereof include an electron beam and ultraviolet rays. Among these, ultraviolet rays are preferable from the viewpoint of operability.
  • the coating composition for forming an intermediate layer usually contains an organic solvent in addition to the actinic radiation curable resin.
  • the organic solvent is not particularly limited as long as it can dissolve the actinic radiation curable resin.
  • hydrocarbons such as toluene and xylene
  • alcohols such as methanol, ethanol, isopropyl alcohol, butanol and cyclohexanol
  • methylene chloride dioxolane
  • propylene glycol monoalkyl ether propylene glycol monomethyl ether, etc.
  • Glycol ethers carboxylic acid esters of glycol ethers such as propylene glycol monomethyl ether acetate, esters such as ethyl acetate, methyl acetate and methyl lactate, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and diacetone alcohol Ketone alcohols and the like.
  • glycol ethers such as propylene glycol monomethyl ether acetate, esters such as ethyl acetate, methyl acetate and methyl lactate, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and diacetone alcohol Ketone alcohols and the like.
  • propylene glycol monoalkyl ethers having 1 to 4 carbon atoms in the alkyl group and propylene glycol monoalkyl ether acetates having 1 to 4 carbon atoms in the alkyl group are preferable.
  • these
  • the coating composition for forming the intermediate layer may contain, for example, a cellulose ester resin, a photopolymerization initiator described later, and the like in addition to the actinic radiation curable resin. More specifically, for example, the intermediate layer forming coating composition may contain a photopolymerization initiator. In the case of polymerization by irradiation with an electron beam, a photopolymerization initiator is not required. However, in the case of polymerization generally used, for example, polymerization by ultraviolet (UV) irradiation, the polymerization is promoted. Therefore, it is preferable to contain a photopolymerization initiator. By doing so, the polymerization temperature can be lowered.
  • UV ultraviolet
  • the photopolymerization initiator it is only necessary to contribute to the initiation of the curing reaction of the actinic radiation curable resin.
  • ⁇ -hydroxyketone, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, ⁇ -amyloxime ester, thioxanthone And derivatives thereof are preferred.
  • these may be used independently and may be used in combination of 2 or more type.
  • the content of the photopolymerization initiator is preferably about 0.1 to 1 part by mass with respect to 100 parts by mass of the actinic radiation curable resin, for example.
  • any light source that generates ultraviolet rays can be used without limitation.
  • Specific examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, carbon arc lamps, metal halide lamps, and xenon lamps.
  • the irradiation conditions of ultraviolet light varies by the light source and the intermediate layer coating composition, etc., the dose of active ray is usually 5 ⁇ 500mJ / cm 2, preferably from 5 ⁇ 150mJ / cm 2.
  • irradiating active rays when irradiating active rays, it is preferably performed while applying tension in the film transport direction, more preferably while applying tension in the width direction.
  • the tension to be applied is preferably 30 to 300 N / m.
  • the method of applying tension is not particularly limited, and tension may be applied in the transport direction on the back roll, or tension may be applied in the width direction or biaxial direction by a tenter. This makes it possible to obtain a film having further excellent flatness.
  • an optically anisotropic layer is formed on the bonding intermediate layer.
  • a coating composition for forming an optically anisotropic layer containing a liquid crystal compound is applied onto the bonding intermediate layer.
  • the coating method is not particularly limited, and a known coating method can be used. Specifically, for example, spin coating method, roll coating method, printing method, dip pulling method, die coating method, casting method, bar coating method, blade coating method, spray coating method, gravure coating method, reverse coating method, and extrusion Examples thereof include a coating method.
  • the coating thickness varies depending on the solid content concentration of the coating composition for forming an optically anisotropic layer. Specifically, for example, the thickness of the formed optically anisotropic layer is within the above range.
  • the dry film thickness is preferably 0.1 to 10 ⁇ m and more preferably 0.2 to 5 ⁇ m as an average film thickness.
  • the coating composition for forming an optically anisotropic layer applied on the bonding intermediate layer is dried.
  • the drying method is not particularly limited as long as the organic solvent in the coating composition for forming an optically anisotropic layer can be dried. Specific examples include air drying, heat removal, and reduced pressure removal. These may be performed alone or in combination of two or more.
  • the liquid crystal compound is aligned by heating the coating composition for forming an optically anisotropic layer applied on the bonding intermediate layer and dried to a temperature higher than the liquid crystal transition temperature of the liquid crystal compound.
  • the alignment time takes about 1 to 10 minutes, for example.
  • the liquid crystal transition temperature refers to a solid-liquid crystal phase transition temperature.
  • the heating up to the liquid crystal transition temperature or higher after coating the coating composition for forming an optically anisotropic layer is preferably up to the liquid crystal-isotropic liquid phase transition temperature or lower.
  • the heating rate is preferably 10 to 150 ° C./second.
  • the coating composition for forming an optically anisotropic layer is cooled below the liquid crystal transition temperature of the liquid crystal compound, the orientation is fixed, and in this state, the coating composition for forming the optically anisotropic layer is irradiated with active rays. To do. By doing so, the orientation is more fixed, and an optically anisotropic layer in which the liquid crystal compound is vertically aligned is formed. That is, in this step, when the liquid crystal compound is a polymerizable liquid crystal compound having a functional group that can be polymerized by irradiation with active rays, the coating composition for forming the optical anisotropic layer is cooled, and then the optical anisotropic layer is formed. This is a step of irradiating the forming coating composition with active rays to cure the optically anisotropic layer forming coating composition. By doing so, an optically anisotropic layer can be formed easily.
  • the coating composition for forming an optically anisotropic layer usually contains an organic solvent described later in addition to the liquid crystal compound.
  • the organic solvent is not particularly limited as long as it can dissolve the liquid crystal compound. Moreover, as an organic solvent, it is preferable that it is a solvent which does not reduce the property of a transparent film base material or the intermediate
  • hydrocarbons such as benzene and toluene
  • ethers such as methoxybenzene and diethylene glycol dimethyl ether
  • ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone
  • propylene Esters such as glycol monomethyl ether acetate, ⁇ -butyrolactone
  • amide solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, tritrichloroethylene
  • Halogen solvent t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol Call, ethylene glycol monomethyl ether, alcohols such as ethyl cellosolve, phenol, phenols such as p-chlorophenol, and the like. These may be used alone or in combination of two or more.
  • organic solvents preferred as a solvent to be used alone are hydrocarbon solvents and glycol monoether acetate solvents such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, and are preferred as solvents to be used in combination. Is a mixed solvent using ethers or ketones in combination with glycols.
  • the solid content concentration of the coating composition for forming an optically anisotropic layer varies depending on the solubility of the liquid crystal compound, the film thickness of the optically anisotropic layer, etc., but is, for example, about 0.1 to 60% by mass. It is preferably about 3 to 40% by mass.
  • the coating composition for forming an optically anisotropic layer contains a photopolymerization initiator described later. It may be.
  • a photopolymerization initiator is not required.
  • polymerization generally used for example, polymerization by ultraviolet (UV) irradiation, the polymerization is promoted. Therefore, it is preferable to contain a photopolymerization initiator. By doing so, the polymerization temperature can be lowered, and immobilization can be suitably performed.
  • the photopolymerization initiator is not particularly limited. Specifically, for example, benzyl (bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, benzoyl methyl benzoate, 4-benzoyl-4'- Methyl diphenyl sulfide, benzyl methyl ketal, dimethylaminomethyl benzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3'-dimethyl-4-methoxybenzophenone, methylobenzoylpho Mate, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1- on, -(4-dodecy
  • the content of the photopolymerization initiator is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, and further preferably 0.5 to 5% by mass. . If the content of the photopolymerization initiator is too small, the effect of the photopolymerization initiator tends not to be exhibited. If the content is too large, the polymerizability of the liquid crystal compound is lowered and the molecular weight is lowered, so that the scratch resistance is reduced. There is a tendency for the sex etc. to decrease.
  • the coating composition for forming an optically anisotropic layer may contain a sensitizer as long as the object of the present invention is not impaired. Although it does not specifically limit as a sensitizer, Specifically, Nippon Kayaku Co., Ltd. Kayacure DETX etc. are mentioned, for example.
  • the coating composition for forming an optically anisotropic layer may contain the following additives as long as the object of the present invention is not impaired.
  • the content of the additive is selected within a range that does not impair the object of the present invention, and is generally preferably 40% by mass or less of the coating composition for forming an optically anisotropic layer, and 20% by mass. % Or less is preferable.
  • the coating composition for forming an optically anisotropic layer containing a solvent may contain a surfactant or the like in order to facilitate coating.
  • the surfactant include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides and polyamine derivatives; polyoxyethylene-polyoxypropylene condensates, primary or Secondary alcohol ethoxylate, alkylphenol ethoxylate, polyethylene glycol and its esters, sodium lauryl sulfate, ammonium lauryl sulfate, lauryl sulfate amines, alkyl-substituted aromatic sulfonates, alkyl phosphates, aliphatic or aromatic sulfonate formalin
  • Anionic surfactants such as condensates; amphoteric surfactants such as laurylamidopropylbetaine and laurylaminoacetic acid betaine; non-polyethylene glycol fatty acid esters
  • the surfactant content varies depending on the type of surfactant, the type of liquid crystal material, the type of solvent, and the type of alignment film on which the solution is applied. Thus, it is preferably 10 ppm to 10% by mass, preferably 100 ppm to 5% by mass, and preferably 0.1 to 1% by mass.
  • the active ray is not particularly limited as long as the coating composition for forming an intermediate layer can be cured, and specific examples thereof include an electron beam and ultraviolet rays. Among these, from the viewpoint of operability, ultraviolet rays and visible light are preferable, and ultraviolet rays are more preferable. Curing with ultraviolet rays is preferable from the viewpoint that the technology is established and it is easier to use than curing with visible light.
  • the wavelength is preferably, for example, 150 to 500 nm, more preferably 250 to 450 nm, and preferably 300 to 400 nm.
  • any light source that generates ultraviolet rays can be used without limitation.
  • low-pressure mercury lamps such as sterilization lamps, fluorescent chemical lamps, and black lights
  • high-pressure discharge lamps such as high-pressure mercury lamps and metal halide lamps
  • short arc discharges such as ultra-high-pressure mercury lamps, xenon lamps, and mercury xenon lamps A lamp etc.
  • use of a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, etc. is recommended.
  • the irradiation conditions of ultraviolet rays vary depending on the light source, the coating composition for forming an optically anisotropic layer, etc., but the irradiation amount of active rays is usually 5 to 500 mJ / cm 2 , preferably 5 to 150 mJ / cm 2 . is there.
  • the transparent film substrate has a long shape
  • the first coating step, the intermediate layer forming step, the second coating step, the orientation step, and the immobilization step are each performed as a transparent film.
  • the width of the transparent film substrate is preferably 1000 mm or more
  • the conveyance speed of the transparent film substrate is preferably 40 m / min or more.
  • the conveyance speed of the transparent film base material here corresponds to the coating speed of the coating composition for forming an intermediate layer and the coating composition for forming an optically anisotropic layer.
  • a coating composition for forming an intermediate layer or a coating for forming an optically anisotropic layer is used.
  • the coating unevenness of the composition occurs, and defects are likely to occur in the formed bonding intermediate layer and optically anisotropic layer.
  • the bonding intermediate layer and the optically anisotropic layer are formed. Generation of defects in the optical compensation film, the adhesion between the bonding intermediate layer and the optically anisotropic layer is sufficiently high, and the orientation of the liquid crystal compound in the optically anisotropic layer is sufficiently high. Can be manufactured.
  • the thickness of the optical compensation film according to the present invention is preferably 20 ⁇ m or more, and more preferably 20 to 80 ⁇ m.
  • the thickness here means the average film thickness.
  • the thickness is measured at 20 to 200 locations in the width direction of the film with a contact-type film thickness meter manufactured by Mitutoyo Corporation, and the average value of the measured values is calculated. Shown as film thickness.
  • the width, physical properties, and shape of the transparent film substrate are not particularly limited and can be appropriately selected according to the purpose of the optical compensation film to be manufactured. From the viewpoint of use in a large-sized liquid crystal display device, use efficiency of a film during polarizing plate processing, and production efficiency, it is preferably 1000 mm or more, and more preferably 1000 to 4000 mm.
  • the polarizing plate includes a polarizing element and a transparent protective film disposed on the surface of the polarizing element, and the transparent protective film is an optical compensation film.
  • the polarizing element is an optical element that emits light by changing the polarization of incident light to linearly polarized light.
  • an optical compensation film is attached to at least one surface of a polarizing element prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution, using a completely saponified polyvinyl alcohol aqueous solution. Those combined are preferred. Further, an optical compensation film may be laminated on the other surface of the polarizing element, or a transparent protective film for another polarizing plate may be laminated.
  • the transparent protective film for the polarizing plate for example, as a commercially available cellulose ester film, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UY-HA, KC8UX-RHA, KC4FR- manufactured by Konica Minolta Opto Co., Ltd. 1, KC4HR-1, KC8UCR-3, KC8UCR-4, KC8UCR-5 and the like are preferably used.
  • resin films such as cyclic olefin resin other than a cellulose-ester film, an acrylic resin, polyester, a polycarbonate. In this case, since the saponification suitability is low, it is preferable to perform an adhesive process on the polarizing plate through an appropriate adhesive layer.
  • the polarizing plate uses an optical compensation film as a protective film laminated on at least one surface side of the polarizing element.
  • the optical compensation film works as an optical compensation film such as a retardation film
  • it is preferable that the slow axis of the optical compensation film is arranged so as to be substantially parallel or perpendicular to the absorption axis of the polarizing element.
  • polarizing element examples include, for example, a polyvinyl alcohol polarizing film.
  • Polyvinyl alcohol polarizing films include those obtained by dyeing iodine on polyvinyl alcohol films and those obtained by dyeing dichroic dyes.
  • a modified polyvinyl alcohol film modified with ethylene is preferably used as the polyvinyl alcohol film.
  • the polarizing element is obtained as follows, for example. First, a film is formed using a polyvinyl alcohol aqueous solution. The obtained polyvinyl alcohol film is uniaxially stretched and then dyed or dyed and then uniaxially stretched. And preferably, a durability treatment is performed with a boron compound.
  • the film thickness of the polarizing element is preferably 5 to 40 ⁇ m, more preferably 5 to 30 ⁇ m, and even more preferably 5 to 20 ⁇ m.
  • a cellulose ester-based optical compensation film containing a cellulose ester is laminated on the surface of the polarizing element, it is preferably bonded with a water-based adhesive mainly composed of completely saponified polyvinyl alcohol. Further, in the case of an optical compensation film other than the cellulose ester-based optical compensation film, it is preferable to perform an adhesive process on the polarizing plate through an appropriate adhesive layer.
  • the polarizing plate as described above uses the optical compensation film according to the above embodiment as a transparent protective film, so that the optical compensation film is excellent in optical compensation performance and the like, and thus a polarizing plate excellent in optical compensation performance and the like is obtained. It is done.
  • an optical compensation film excellent in optical compensation performance is applied as the transparent protective film of the polarizing plate.
  • the viewing angle is increased and the contrast is increased.
  • a polarizing plate capable of realizing high image quality of the liquid crystal display device such as improvement can be obtained.
  • the liquid crystal display device includes a liquid crystal cell and two polarizing plates arranged so as to sandwich the liquid crystal cell.
  • the liquid crystal cell is a cell in which a liquid crystal substance is filled between a pair of electrodes, and by applying a voltage to the electrodes, the alignment state of the liquid crystal is changed and the amount of transmitted light is controlled. Since such a liquid crystal display device uses a polarizing plate excellent in optical compensation performance and the like, optical characteristics such as viewing angle characteristics of the liquid crystal display device can be improved. Therefore, high definition of the liquid crystal display device can be realized.
  • the liquid crystal display device include a reflective type, a transmissive type, and a transflective type, and also include a TN type, an STN type, an OCB type, a HAN type, and a VA type (PVA type). , MVA type), IPS type and the like.
  • the polarizing plate provided with the optical compensation film according to the present embodiment is suitably used in the IPS liquid crystal display device.
  • IPS In-Plane-Switching
  • a liquid crystal display device can be manufactured.
  • the IPS mode includes a fringe electric field switching (FFS) mode, and similarly to the IPS mode, a polarizing plate including the optical compensation film according to the present embodiment can be incorporated, and similar effects can be obtained.
  • a liquid crystal display device having can be manufactured.
  • the liquid crystal layer of the liquid crystal panel in the IPS mode type liquid crystal display device is homogeneously aligned in parallel with the substrate surface in the initial state, and the director of the liquid crystal layer in the plane parallel to the substrate is parallel to the electrode wiring direction when no voltage is applied. Or somewhat have an angle. Then, the direction of the director of the liquid crystal layer when a voltage is applied shifts in a direction perpendicular to the electrode wiring direction with the application of the voltage, and the director direction of the liquid crystal layer is compared to the direction of the director when no voltage is applied.
  • the liquid crystal layer when the voltage is applied rotates the azimuth angle of the polarization by 90 ° like a half-wave plate, and the transmission axis of the output side polarizing plate and the azimuth angle of the polarization Match and the display is white.
  • the thickness of the liquid crystal layer is constant, but since it is driven by a lateral electric field, it may be possible to increase the response speed with respect to switching by slightly increasing the thickness of the liquid crystal layer.
  • a polarizing plate provided with a film, the effect can be maximized even when the thickness of the liquid crystal layer is not constant.
  • the thickness is preferably 2 to 6 ⁇ m, more preferably 3 to 5.5 ⁇ m. By doing so, a liquid crystal layer that can effectively exhibit excellent performance is obtained.
  • a polarizing plate having an optical compensation film excellent in optical compensation performance is used, it is possible to provide a high-quality liquid crystal display device with an improved viewing angle and contrast.
  • Example 1 As the transparent cellulose ester-based resin film substrate, a cellulose acetate propionate film (CAP, trade name KC-4KR, manufactured by Konica Minolta Opto) was used.
  • the resin film had a thickness of 60 ⁇ m and a width of 1.5 m.
  • the film thickness of the back coat layer was 0.2 ⁇ m.
  • (Coating composition for forming intermediate layer for bonding) 13 parts by mass of urethane acrylate oligomer (UV-7510B Nippon Synthetic Chemical Co., Ltd.)) Propylene glycol monomethyl ether 290 parts by mass Isopropyl alcohol 685 parts by mass Photopolymerization initiator 0.05 parts by mass (Lucirin TPO (manufactured by BASF Corporation)
  • the intermediate layer-forming coating composition is applied to the other side of the cellulose acetate propionate film with a wire bar (# 3), dried at a temperature of 80 ° C.
  • the thickness of the bonding intermediate layer after drying was 0.5 ⁇ m.
  • (Coating composition for forming a polymerizable liquid crystal layer) 25 parts by mass of UV-polymerizable liquid crystal material (UCL018 manufactured by Dainippon Ink & Chemicals, Inc.) Propylene glycol monomethyl ether acetate 80 parts by mass Photopolymerization initiator 0.04 parts by mass (Lucirin TPO, manufactured by Bassf Corporation) 0.02 parts by mass of hindered amine (LS-765, manufactured by Sankyo Lifetech Co., Ltd.)
  • the above-mentioned coating composition for forming a polymerizable liquid crystal layer was applied to the surface of the above-mentioned bonding intermediate layer with a thickness of 12 ⁇ m by a die coater.
  • the rod-shaped liquid crystal compound was orientated, and the optically anisotropic layer containing a liquid crystal compound was formed.
  • the film thickness of the optically anisotropic layer was 2 ⁇ m.
  • the center line average roughness (Ra) of the base layer surface of the back coat layer of the optical compensation film obtained in this Example 1 in this way was analyzed under a condition of a temperature of 23 ° C. and a humidity of 50 ⁇ 5% RH. Using a microscope (zygo New View 5000, manufactured by Canon Sales Co., Ltd.), measurement was performed with an objective lens of 50 times and an image zoom of 1.0 times.
  • Example 2 Although it carries out similarly to the case of the said Example 1, a different point from the case of the said Example 1 is a solvent 1: methyl ethyl ketone (MEK, boiling point: 80 degreeC, SP value) as a solvent of the coating composition for backcoat layer formation. 9.3) 10 parts by mass, and solvent 2: methanol (MeOH, boiling point: 64.6 ° C., SP value: 14.5) 90 parts by mass, as shown in Table 2 below, in a ratio of 10:90 It is in the point used in.
  • MEK methyl ethyl ketone
  • Example 3 Although it carries out similarly to the case of the said Example 1, the point different from the case of the said Example 1 is a solvent 1: ethyl acetate (boiling point: 78 degreeC, SP value :) as a solvent of the coating composition for backcoat layer formation. 8.9) 30 parts by mass and solvent 2: 70 parts by mass of methanol (MeOH, boiling point: 64.6 ° C., SP value: 14.5) at a ratio of 30:70 as shown in Table 2 below. It is in the point used.
  • solvent 1 ethyl acetate
  • solvent 2 70 parts by mass of methanol (MeOH, boiling point: 64.6 ° C., SP value: 14.5) at a ratio of 30:70 as shown in Table 2 below. It is in the point used.
  • Example 4 The same procedure as in Example 1 is performed except that the fine particle of the backcoat layer forming coating composition is a 2% isopropyl alcohol dispersion of silica fine particles (Seahoster KE-P10). , Manufactured by Nippon Shokubai Co., Ltd., average particle diameter: 100 nm), 0.8 parts by mass.
  • the fine particle of the backcoat layer forming coating composition is a 2% isopropyl alcohol dispersion of silica fine particles (Seahoster KE-P10). , Manufactured by Nippon Shokubai Co., Ltd., average particle diameter: 100 nm), 0.8 parts by mass.
  • Example 5 The same procedure as in Example 1 is carried out, but the difference from Example 1 is that a 2% isopropyl alcohol dispersion of silica fine particles (Seahoster KE-P100) is used as the fine particles of the coating composition for backcoat layer formation. , Manufactured by Nippon Shokubai Co., Ltd., average particle size: 1000 nm), 0.8 parts by mass.
  • Example 6 The same procedure as in Example 1 is carried out, but the difference from Example 1 is that a 2% isopropyl alcohol dispersion (RSP-3021D, acrylic fine particles) is used as the fine particles of the coating composition for forming the backcoat layer. This is in that 0.8 parts by mass of Toyo Ink Co., Ltd.
  • Example 7 Although it carries out similarly to the case of the said Example 1, a different point from the case of the said Example 1 is a cellulose triacetate film (TAC, brand name KC4UYW, the Konica Minolta Opto company make) as a transparent cellulose-ester-type resin film base material. ) Is used. The resin film had a thickness of 60 ⁇ m and a width of 1.5 m. Comparative Example 1 For comparison, it was carried out with the solvent of the coating composition for backcoat layer formation being different from that in Example 1 above.
  • TAC cellulose triacetate film
  • KC4UYW the Konica Minolta Opto company make
  • solvent 1 propylene glycol monomethyl ether acetate (PGMEA, boiling point: 146 ° C., SP value: 9.6) 5 parts by mass
  • solvent 2 isopropyl alcohol (IPA, Boiling point: 82.4 ° C., SP value: 11.5)
  • IPA isopropyl alcohol
  • solvent 1 cyclohexanone (boiling point: 155 ° C., SP value: 9.6) 90 parts by mass
  • solvent 2 normal propyl alcohol (NPA, boiling point: 97 ° C., SP value: 12) As shown in Table 2 below, 10 parts by mass is used at a ratio of 90:10.
  • each optical compensation film sample was overlaid under a high humidity condition of a temperature of 50 ° C. and a humidity of 90% RH, and a load of 200 g was obtained. After performing the durability treatment for 3 hours, the retardation unevenness was visually evaluated for each sample under the crossed Nicol condition according to the above criteria. The obtained results are shown in Table 3 below.
  • each optical compensation film sample was overlaid under a high humidity condition of a temperature of 50 ° C. and a humidity of 90% RH, and a load of 200 g was obtained. After performing durability treatment for 3 hours, the sticking (blocking property) was visually evaluated for each sample under crossed Nicol conditions according to the above criteria. The obtained results are shown in Table 3 below.
  • the optical compensation films obtained in Examples 1 to 7 of the present invention have a center line average roughness (Ra) in a region where no fine particles exist on the backcoat layer base layer surface.
  • Ra center line average roughness
  • the optical compensation film includes an optical film including a transparent film substrate and a liquid crystal compound. It was possible to suppress retardation unevenness due to deformation of the isotropic layer (liquid crystal layer) and to have excellent surface smoothness (low haze).
  • the optical compensation film obtained in Comparative Example 1 has a low haze because the center line average roughness (Ra) in the region where the fine particles on the backcoat layer base layer surface are not present is small.
  • the retardation unevenness due to the deformation of the optically anisotropic layer (liquid crystal layer), particularly the retardation unevenness after the durability treatment cannot be suppressed.
  • the optical compensation film obtained in Comparative Example 2 had a very high haze value because the center line average roughness (Ra) in the region where fine particles on the backcoat layer base layer surface were not present was large. .
  • the optical compensation film obtained in Comparative Example 3 has a very large average particle size of the fine particles contained in the backcoat layer, it has a very high haze value. A satisfactory level was not obtained.

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Abstract

Disclosed are: an optical compensation film in which blocking (adhesion) is improved to prevent the retardation unevenness caused by the deformation of a transparent film base material and an optical anisotropic layer containing a liquid crystalline compound (a liquid crystal layer) and which has excellent surface smoothness (low haze); and a polarizing plate and a liquid crystal display device, each of which is equipped with the optical compensation film. In the optical compensation film, an optical anisotropic layer containing an oriented liquid crystalline compound is provided on one surface of a cellulose ester resin transparent film base material, and a back coat layer comprising a cellulose ester resin binder and microparticls is provided on the other surface of the transparent base material, wherein the microparticles contained in the back coat layer have particle diameters of 1 μm or smaller, and the center line average roughness (Ra) of an area on the surface of the base layer of the back coat layer in which the microparticles are not present is 2 to 10 nm.

Description

光学補償フィルム、偏光板及び液晶表示装置Optical compensation film, polarizing plate, and liquid crystal display device
　本発明は、光学補償フィルム、偏光板及び液晶表示装置に関するものである。 The present invention relates to an optical compensation film, a polarizing plate, and a liquid crystal display device.
　一般に、液晶表示装置には、視野角特性等の光学特性を改善するために、光学補償性能を有する光学フィルムが使用されている。このような光学補償フィルムとしては、液晶化合物を含有し、その液晶化合物が配向された光学異方性層を備えた光学補償フィルムが知られている。 Generally, in a liquid crystal display device, an optical film having optical compensation performance is used in order to improve optical characteristics such as viewing angle characteristics. As such an optical compensation film, an optical compensation film containing an optical anisotropic layer containing a liquid crystal compound and having the liquid crystal compound aligned is known.
　一方、透明性フィルム基材上に光学異方性層を備える光学補償フィルムには、光学異方性層を設けた側と反対側の面にバックコート層を設けることが好ましい。この場合、バックコート層は、好ましくはブロッキング防止層を兼ねて塗設され、そのため、バックコート層形成用塗布組成物には、ブロッキング防止機能を持たせるための微粒子を添加することが行なわれている。 On the other hand, it is preferable to provide a backcoat layer on the side opposite to the side where the optically anisotropic layer is provided in the optical compensation film provided with the optically anisotropic layer on the transparent film substrate. In this case, the back coat layer is preferably applied also as an anti-blocking layer, and therefore fine particles for imparting an anti-blocking function are added to the coating composition for forming the back coat layer. Yes.
　このような光学補償フィルムとしては、具体的には、例えば下記の特許文献１～３に記載のものが挙げられる。 Specific examples of such an optical compensation film include those described in Patent Documents 1 to 3 below.
　特許文献１には、液晶表示装置の光学補償に寄与する液晶化合物を含む光学異方性層等を安定的にかつ良好な平面平滑性を保持して作製するのに有用な塗布組成物が記載されている。そして、特許文献１には、光学補償フィルムの光学異方性層と反対側の面に、バックコート層を設けることが記載されている。 Patent Document 1 describes a coating composition useful for producing an optically anisotropic layer containing a liquid crystal compound that contributes to optical compensation of a liquid crystal display device while maintaining stable and good planar smoothness. Has been. Patent Document 1 describes that a backcoat layer is provided on the surface of the optical compensation film opposite to the optically anisotropic layer.
　また、特許文献２及び３には、透明性フィルム基材の片側に機能性薄膜層を有し、反対側にセルロースエステル、微粒子及び有機溶剤を構成成分とするバックコート層を有する光学補償フィルムが記載されている。 Patent Documents 2 and 3 include an optical compensation film having a functional thin film layer on one side of a transparent film substrate and a backcoat layer containing cellulose ester, fine particles and an organic solvent as constituent components on the opposite side. Are listed.
特開２００８－１５０４８９号公報JP 2008-150489 A 特開２００５－２６６２３１号公報JP 2005-266231 A 特開２００７－３２００５２号公報JP 2007-320052 A
　しかしながら、液晶塗布フィルムのような表面平滑性（低ヘイズ）が求められる光学補償フィルムにおいて、液晶化合物を含む光学異方性層側の面と反対側面のハードコート層（ブロッキング防止層）は、製造工程の重要な課題である。光学補償フィルムの巻き締りにより、ブロッキング（巻き状態での貼り付き、変形）が発生すると、透明性フィルム基材および光学異方性層（液晶層）が変形し、リタデーションムラ（光学値変動によるムラ）と呼ばれる外観上および機能上の不具合が発生してしまうという問題があった。 However, in an optical compensation film that requires surface smoothness (low haze) such as a liquid crystal coated film, a hard coat layer (anti-blocking layer) on the side opposite to the surface on the optically anisotropic layer side containing a liquid crystal compound is manufactured. This is an important process issue. When blocking (sticking in a wound state, deformation) occurs due to tightening of the optical compensation film, the transparent film base material and the optical anisotropic layer (liquid crystal layer) are deformed, and retardation unevenness (unevenness due to optical value fluctuation) ) Has a problem in appearance and function.
　本発明の目的は、上記の従来技術の問題を解決し、セルロース系樹脂フィルムよりなる透明性フィルム基材の片面に、光学異方性層（液晶層）が設けられ、同他面に、微粒子とバインダーを含むバックコート層が設けられている光学補償フィルムについて、ブロッキング（貼り付き）の改善により、透明性フィルム基材及び液晶化合物を含む光学異方性層（液晶層）の変形によるリタデーションムラを抑制できるとともに、すぐれた表面平滑性（低ヘイズ）を有する光学補償フィルム、これを用いた偏光板及び液晶表示装置を提供することにある。 The object of the present invention is to solve the above-mentioned problems of the prior art, wherein an optically anisotropic layer (liquid crystal layer) is provided on one side of a transparent film substrate made of a cellulose resin film, and fine particles are provided on the other side. Retardation unevenness due to deformation of optically anisotropic layer (liquid crystal layer) containing transparent film base material and liquid crystal compound due to improvement of blocking (adhesion) for optical compensation film provided with back coat layer containing binder An optical compensation film having excellent surface smoothness (low haze), a polarizing plate using the same, and a liquid crystal display device are provided.
　本発明者は、上記の点に鑑み鋭意研究を重ねた結果、セルロース系樹脂フィルムよりなる透明性フィルム基材の片面に、液晶化合物を含む光学異方性層（液晶層）が設けられ、同他面に、微粒子とバインダーを含むバックコート層が設けられた光学補償フィルムについて、バックコート層基層表面の微粒子の存在しない領域の表面粗さが小さいと、ブロッキング改善効果が薄れてしまうことを見出した。そして、バックコート層の形成の際に、バックコート層形成用塗布組成物中の溶剤種の選定により、バックコート層基層表面の微粒子が存在しない領域の表面粗さを、所定の比較的粗い範囲に制御することにより、光学補償フィルムのブロッキング（貼り付き）を改善することができ、これにより、透明性フィルム基材及び液晶化合物を含む光学異方性層（液晶層）の変形によるリタデーションムラを抑制できることを見い出し、本発明を完成するに至ったものである。 As a result of intensive studies in view of the above points, the present inventor has provided an optically anisotropic layer (liquid crystal layer) containing a liquid crystal compound on one side of a transparent film substrate made of a cellulose resin film. The optical compensation film provided with a backcoat layer containing fine particles and a binder on the other side has been found to have a reduced blocking effect if the surface roughness of the region where the fine particles are not present on the backcoat layer base layer surface is small. It was. Then, when forming the backcoat layer, the surface roughness of the region where fine particles on the surface of the backcoat layer base layer are not present is determined by selecting a solvent type in the coating composition for forming the backcoat layer. By controlling the thickness of the optical compensation film, it is possible to improve the blocking (adhesion) of the optical compensation film, thereby reducing retardation unevenness due to deformation of the optically anisotropic layer (liquid crystal layer) containing the transparent film substrate and the liquid crystal compound. It has been found that it can be suppressed, and the present invention has been completed.
　上記の目的を達成するために、請求項１の光学補償フィルムの発明は、セルロースエステル系樹脂透明性フィルム基材の片面に、配向された液晶化合物を含む光学異方性層が設けられ、同透明性フィルム基材の他面に、セルロースエステル系樹脂バインダーと微粒子とを含有するバックコート層が設けられている光学補償フィルムにおいて、バックコート層に含まれる微粒子の粒径が１μｍ以下であり、バックコート層基層表面の微粒子の存在しない領域の中心線平均粗さ（Ｒａ）が、２～１０ｎｍの範囲であることを特徴としている。 In order to achieve the above object, an optical compensation film according to claim 1 is provided with an optically anisotropic layer containing an aligned liquid crystal compound on one side of a cellulose ester resin transparent film substrate. In the optical compensation film provided with a back coat layer containing a cellulose ester resin binder and fine particles on the other surface of the transparent film substrate, the particle size of the fine particles contained in the back coat layer is 1 μm or less, The center line average roughness (Ra) of the region where fine particles are not present on the back coat layer base layer surface is in the range of 2 to 10 nm.
　請求項２の発明は、請求項１に記載の光学補償フィルムであって、透明性フィルム基材の片面と、液晶化合物を含む光学異方性層との間に、接合用中間層が設けられていることを特徴としている。 The invention according to claim 2 is the optical compensation film according to claim 1, wherein a bonding intermediate layer is provided between one side of the transparent film substrate and the optically anisotropic layer containing the liquid crystal compound. It is characterized by having.
　請求項３の発明は、請求項１または２に記載の光学補償フィルムであって、セルロースエステル系樹脂透明性フィルム基材が、セルロースアセテートプロピオネートフィルムであることを特徴としている。 The invention of claim 3 is the optical compensation film of claim 1 or 2, wherein the cellulose ester resin transparent film substrate is a cellulose acetate propionate film.
　請求項４の発明は、請求項１から３のいずれか１項に記載の光学補償フィルムを有することを特徴とする偏光板である。 The invention of claim 4 is a polarizing plate having the optical compensation film according to any one of claims 1 to 3.
　請求項５の発明は、請求項４に記載の偏光板を有することを特徴とする液晶表示装置である。 The invention of claim 5 is a liquid crystal display device having the polarizing plate of claim 4.
　請求項１の光学補償フィルムの発明は、セルロースエステル系樹脂透明性フィルム基材の片面に、配向された液晶化合物を含む光学異方性層が設けられ、同透明性フィルム基材の他面に、セルロースエステル系樹脂バインダーと微粒子とを含有するバックコート層が設けられている光学補償フィルムにおいて、バックコート層に含まれる微粒子の粒径が１μｍ以下であり、バックコート層基層表面の微粒子の存在しない領域の中心線平均粗さ（Ｒａ）が、２～１０ｎｍの範囲であるもので、請求項１の発明によれば、バックコート層基層表面の微粒子が存在しない領域の中心線平均粗さ（Ｒａ）を、所定の比較的粗い範囲に制御することにより、光学補償フィルムのブロッキング（貼り付き）を改善することができ、これにより、光学補償フィルムについて、透明性フィルム基材及び液晶化合物を含む光学異方性層（液晶層）の変形によるリタデーションムラを抑制できるとともに、すぐれた表面平滑性（低ヘイズ）を有するという効果を奏する。 In the invention of the optical compensation film of claim 1, an optically anisotropic layer containing an oriented liquid crystal compound is provided on one side of a cellulose ester resin transparent film base, and the other side of the transparent film base is provided. In an optical compensation film provided with a back coat layer containing a cellulose ester resin binder and fine particles, the fine particles contained in the back coat layer have a particle size of 1 μm or less, and the presence of fine particles on the surface of the back coat layer base layer The center line average roughness (Ra) of the region not to be removed is in the range of 2 to 10 nm. According to the invention of claim 1, the center line average roughness ( By controlling Ra to a predetermined relatively rough range, the blocking (sticking) of the optical compensation film can be improved. For Irumu, it is possible to suppress the retardation unevenness due to deformation of the optically anisotropic layer (the liquid crystal layer) comprising a transparent film substrate and a liquid crystal compound, an effect that has excellent surface smoothness (low haze).
　請求項２の発明は、請求項１に記載の光学補償フィルムであって、透明性フィルム基材の片面と、液晶化合物を含む光学異方性層との間に、接合用中間層が設けられているもので、請求項２の発明によれば、接合用中間層及び光学異方性層において欠陥の発生を抑制でき、接合用中間層と光学異方性層との密着性が充分に高く、さらに、光学異方性層の液晶化合物の配向性が充分に高い光学補償フィルムを得ることができるという効果を奏する。 The invention according to claim 2 is the optical compensation film according to claim 1, wherein a bonding intermediate layer is provided between one side of the transparent film substrate and the optically anisotropic layer containing the liquid crystal compound. Therefore, according to the invention of claim 2, the occurrence of defects in the bonding intermediate layer and the optically anisotropic layer can be suppressed, and the adhesion between the bonding intermediate layer and the optically anisotropic layer is sufficiently high. Furthermore, there is an effect that an optical compensation film having a sufficiently high orientation of the liquid crystal compound of the optically anisotropic layer can be obtained.
　上記の請求項１または２に記載の光学補償フィルムにおいては、セルロースエステル系樹脂透明性フィルム基材としては、透明性が高い点から、セルロースアセテートプロピオネートフィルムであることが好ましい。 In the optical compensation film according to claim 1 or 2, the cellulose ester resin transparent film substrate is preferably a cellulose acetate propionate film from the viewpoint of high transparency.
　請求項４の発明は、請求項１から３のいずれか１項に記載の光学補償フィルムを有する偏光板であり、請求項４の発明によれば、偏光板の透明保護フィルムとして、光学補償性能に優れた光学補償フィルムが適用されているので、例えば、液晶表示装置に適用した際に、視野角の拡大やコントラストの向上等の、液晶表示装置の高画質化を実現できる偏光板が得られる。 Invention of Claim 4 is a polarizing plate which has an optical compensation film of any one of Claim 1 to 3, According to invention of Claim 4, as a transparent protective film of a polarizing plate, optical compensation performance For example, when applied to a liquid crystal display device, a polarizing plate that can realize high image quality of the liquid crystal display device, such as widening of the viewing angle and improvement of contrast, can be obtained. .
　請求項５の発明は、請求項４に記載の偏光板を有する液晶表示装置であり、請求項５の発明によれば、光学補償性能に優れた光学補償フィルムを具備する偏光板を用いるので、視野角の拡大やコントラスト等が向上された、高画質な液晶表示装置を提供することができる。 The invention of claim 5 is a liquid crystal display device having the polarizing plate of claim 4, and according to the invention of claim 5, a polarizing plate comprising an optical compensation film excellent in optical compensation performance is used. A high-quality liquid crystal display device with improved viewing angle, contrast, and the like can be provided.
　つぎに、本発明の実施の形態を説明するが、本発明は、これらに限定されるものではない。
（光学補償フィルム）
　本発明による光学補償フィルムは、セルロースエステル系樹脂透明性フィルム基材の片面に、配向された液晶化合物を含む光学異方性層が設けられ、同透明性フィルム基材の他面に、セルロースエステル系樹脂バインダーと微粒子とを含有するバックコート層が設けられている光学補償フィルムであって、バックコート層に含まれる微粒子の粒径が１μｍ以下であり、バックコート層基層表面の微粒子の存在しない領域の中心線平均粗さ（Ｒａ）が、２～１０ｎｍの範囲であることを特徴としている。 Next, embodiments of the present invention will be described, but the present invention is not limited thereto.
(Optical compensation film)
The optical compensation film according to the present invention is provided with an optically anisotropic layer containing an oriented liquid crystal compound on one side of a cellulose ester-based resin transparent film base, and on the other side of the transparent film base. An optical compensation film provided with a backcoat layer containing a resin binder and fine particles, wherein the particle size of the fine particles contained in the backcoat layer is 1 μm or less, and no fine particles are present on the surface of the backcoat layer base layer. The center line average roughness (Ra) of the region is in the range of 2 to 10 nm.
　また、本発明に係る光学補償フィルムは、透明性フィルム基材と、透明性フィルム基材上に形成された機能層とを備え、機能層が、活性線硬化樹脂を含有する接合用中間層と、液晶化合物を含有する光学異方性層との少なくとも２つの層を積層したものであり、接合用中間層が光学異方性層より透明性フィルム基材側に存在する。 Moreover, the optical compensation film according to the present invention comprises a transparent film substrate and a functional layer formed on the transparent film substrate, and the functional layer contains an actinic radiation curable resin and a bonding intermediate layer. The optically anisotropic layer containing a liquid crystal compound is laminated, and a bonding intermediate layer is present closer to the transparent film substrate than the optically anisotropic layer.
　光学補償フィルムとしては、機能層として、接合用中間層及び光学異方性層のみで構成されたものに限定されず、他の層を備えたものであってもよい。具体的には、例えば、機能層として、透明性フィルム基材と接合用中間層との間に介在する第２の中間層として、下地層を備えていてもよい。下地層としては、例えば、帯電防止層、溶出抑制層、及び防眩層等として働くものが挙げられる。 The optical compensation film is not limited to a functional layer composed of only a bonding intermediate layer and an optically anisotropic layer, and may include other layers. Specifically, for example, an underlayer may be provided as a functional layer as a second intermediate layer interposed between the transparent film substrate and the bonding intermediate layer. Examples of the base layer include those that function as an antistatic layer, an elution suppression layer, an antiglare layer, and the like.
　本発明では、セルロースエステル系樹脂透明性フィルム基材の光学異方性層を設けた側の面と反対側の面にはバックコート層が設けられている。 In the present invention, a back coat layer is provided on the surface of the cellulose ester resin transparent film substrate opposite to the surface on which the optically anisotropic layer is provided.
　バックコート層は、活性エネルギー線硬化樹脂層やその他の層を設けることで生じるカールを矯正するために設けられるとともに、バックコート層は、ブロッキング防止層を兼ねて塗設され、その場合、バックコート層用塗布組成物には、ブロッキング防止機能を持たせるために、微粒子が添加されている。 The back coat layer is provided to correct curling caused by providing the active energy ray-curable resin layer and other layers, and the back coat layer is also provided as an anti-blocking layer. Fine particles are added to the layer coating composition in order to provide an anti-blocking function.
　本発明による光学補償フィルムにおいては、バックコート層に含まれる微粒子の粒径が１μｍ以下である。ここで、バックコート層に含まれる微粒子の粒径が１μｍを超えると、光学補償フィルムのヘイズの上昇が発生するほか、微粒子脱落の可能性が高まり、工程汚染の懸念があるため、好ましくない。 In the optical compensation film according to the present invention, the particle size of the fine particles contained in the backcoat layer is 1 μm or less. Here, when the particle size of the fine particles contained in the backcoat layer exceeds 1 μm, the haze of the optical compensation film is increased, the possibility of fine particles falling off is increased, and there is a concern about process contamination.
　さらに、本発明による光学補償フィルムにおいては、バックコート層基層表面の微粒子の存在しない領域の中心線平均粗さ（Ｒａ）が、２～１０ｎｍの範囲である。 Furthermore, in the optical compensation film according to the present invention, the center line average roughness (Ra) of the region where the fine particles are not present on the surface of the backcoat layer base layer is in the range of 2 to 10 nm.
　本発明による光学補償フィルムのバックコート層の基層表面の中心線平均粗さ（Ｒａ）は、例えば温度２３℃、湿度５０±５％ＲＨの条件下において、３次元表面構造解析顕微鏡（ｚｙｇｏ Ｎｅｗ Ｖｉｅｗ ５０００、キャノン販売株式会社製）を用い、対物レンズ５０倍、イメージズーム１．０倍で測定することができる。このとき、５０ｎｍ以上のピークがある微粒子存在領域部分をカットした領域部分（以下、微粒子が存在しない領域部分という）であるバックコート層基層表面について中心線平均粗さ（Ｒａ）の測定を行うものである。 The center line average roughness (Ra) of the base layer surface of the back coat layer of the optical compensation film according to the present invention is, for example, a three-dimensional surface structure analysis microscope (zygo New View) under conditions of a temperature of 23 ° C. and a humidity of 50 ± 5% RH. 5000, manufactured by Canon Sales Co., Ltd.) and can be measured with an objective lens 50 times and an image zoom 1.0 times. At this time, the center line average roughness (Ra) is measured for the surface of the backcoat layer base layer, which is a region portion (hereinafter referred to as a region portion where no fine particles are present) cut from the fine particle existence region portion having a peak of 50 nm or more. It is.
　ここで、バックコート層基層表面の微粒子の存在しない領域の中心線平均粗さ（Ｒａ）が２ｎｍ未満と小さいと、ブロッキング改善効果が薄れてしまうので、好ましくない。また、バックコート層基層表面の微粒子の存在しない領域の中心線平均粗さ（Ｒａ）が、１０ｎｍを超えると、光学補償フィルムの表面平滑性が劣り、ヘイズが高くなって、透明性が劣化するので、好ましくない。 Here, if the center line average roughness (Ra) of the region where the fine particles are not present on the back coat layer base layer surface is as small as less than 2 nm, the effect of improving blocking is reduced, which is not preferable. Moreover, when the center line average roughness (Ra) of the area | region where the microparticles | fine-particles of the backcoat layer base layer do not exist exceeds 10 nm, the surface smoothness of an optical compensation film is inferior, haze becomes high, and transparency deteriorates. Therefore, it is not preferable.
　本発明者は、鋭意研究を重ねた結果、光学補償フィルムの透明性フィルム基材成分に対して、高溶解性、低溶解性の溶剤を各種割合で混合させた溶媒をバックコート層形成用組成物の溶剤に使用することにより、基材の膨潤度の差から、目標の表面粗さが得られることを見出した。 As a result of extensive research, the inventor has developed a composition for forming a backcoat layer by mixing a solvent having a high solubility and a low solubility in various proportions with respect to the transparent film substrate component of the optical compensation film. It has been found that the target surface roughness can be obtained from the difference in the degree of swelling of the substrate by using it as a solvent for the product.
　以下、本発明による光学補償フィルムについて、セルロースエステル系樹脂透明性フィルム基材、液晶化合物を含む光学異方性層、接合用中間層、およびバックコート層の順に説明する。
（透明性フィルム基材）
　透明性フィルム基材としては、透明性があり、光学補償フィルムの基材として用いることができるものであれば、特に限定されない。なお、ここで透明性があるとは、可視光の透過率が６０％以上であることであり、好ましくは８０％以上、より好ましくは９０％以上である。透明性フィルム基材としては、具体的には、例えば、透明性樹脂を含有する樹脂フィルム等が挙げられる。 Hereinafter, the optical compensation film according to the present invention will be described in the order of a cellulose ester-based resin transparent film substrate, an optically anisotropic layer containing a liquid crystal compound, a bonding intermediate layer, and a backcoat layer.
(Transparent film substrate)
The transparent film substrate is not particularly limited as long as it is transparent and can be used as a substrate for an optical compensation film. Here, being transparent means that the transmittance of visible light is 60% or more, preferably 80% or more, and more preferably 90% or more. Specific examples of the transparent film substrate include a resin film containing a transparent resin.
　透明性樹脂としては、光学補償フィルムの基材として用いることができるものであれば、特に限定されず、例えば、フィルム基材等に成形した際に、透明性があることが好ましい。透明性樹脂としては、具体的には、例えば、セルロースエステル系樹脂が挙げられる。 The transparent resin is not particularly limited as long as it can be used as the base material of the optical compensation film. For example, it is preferable that the transparent resin has transparency when formed into a film base material. Specific examples of the transparent resin include cellulose ester resins.
　セルロースエステル系樹脂としては、特に限定されない。具体的には、例えば、セルロース樹脂の、炭素数が２～２２程度のカルボン酸エステルであることが好ましく、炭素数が２～６の低級脂肪酸エステルであることがより好ましい。また、芳香族カルボン酸のエステルであってもよい。 The cellulose ester resin is not particularly limited. Specifically, for example, a carboxylic acid ester having about 2 to 22 carbon atoms is preferable, and a lower fatty acid ester having 2 to 6 carbon atoms is more preferable. Moreover, ester of aromatic carboxylic acid may be sufficient.
　また、セルロースエステル系樹脂としては、より具体的には、例えば、セルロースアセテートプロピオネート樹脂、セルロースアセテートブチレート樹脂、及びセルロースアセテートプロピオネートブチレート樹脂のようなアセチル基の他にプロピオネート基又はブチレート基が結合したセルロースの混合脂肪酸エステル等が挙げられる。この中でも、プロピオネート基を置換基として含むセルロースアセテートプロピオネート樹脂は、耐水性に優れ、透明性が高い点から、液晶画像表示装置用のフィルムとして特に有用である。 Further, as the cellulose ester resin, more specifically, for example, in addition to acetyl groups such as cellulose acetate propionate resin, cellulose acetate butyrate resin, and cellulose acetate propionate butyrate resin, propionate groups or Examples thereof include mixed fatty acid esters of cellulose to which butyrate groups are bonded. Among these, a cellulose acetate propionate resin containing a propionate group as a substituent is particularly useful as a film for a liquid crystal image display device because of its excellent water resistance and high transparency.
　セルロースエステル系樹脂としては、より具体的には、例えば、アセチル基の置換度をＸ、プロピオニル基又はブチリル基の置換度をＹ、総アシル基置換度をＸ＋Ｙとした時、ＸとＹとが下記式（Ｉ）及び（II）を満たすセルロースの混合脂肪酸エステルを有するセルロースエステル系樹脂が好ましい。 More specifically, as the cellulose ester resin, for example, when the substitution degree of acetyl group is X, the substitution degree of propionyl group or butyryl group is Y, and the total acyl group substitution degree is X + Y, X and Y are A cellulose ester resin having a mixed fatty acid ester of cellulose satisfying the following formulas (I) and (II) is preferable.
　　２≦Ｘ＋Ｙ≦３　　　　（Ｉ）
　　０≦Ｙ≦１．５　　　　（II）
　また、上記式（Ｉ）及び（II）に加えて、下記式（III）及び下記式（VI）を満たすセルロースアセテートプロピオネート樹脂が特に好ましい。 2 ≦ X + Y ≦ 3 (I)
0 ≦ Y ≦ 1.5 (II)
In addition to the above formulas (I) and (II), a cellulose acetate propionate resin satisfying the following formula (III) and the following formula (VI) is particularly preferable.
　　１≦Ｘ≦２．５　　　　（III）
　　０．１≦Ｙ≦１．５　　（IV）
　また、アシル基で置換されていない部分は通常水酸基として存在している。これらのセルロースエステル系樹脂は、公知の方法で合成することができる。アシル基の置換度の測定方法は、ＡＳＴＭ－Ｄ８１７－９６の規定に準じて測定することができる。 1 ≦ X ≦ 2.5 (III)
0.1 ≦ Y ≦ 1.5 (IV)
In addition, the portion not substituted with an acyl group usually exists as a hydroxyl group. These cellulose ester resins can be synthesized by a known method. The method for measuring the substitution degree of the acyl group can be measured in accordance with the provisions of ASTM-D817-96.
　アシル基としては、直鎖であっても分岐していてもよく、また環を形成していてもよい。アシル基の置換度が同程度の場合、アシル基の炭素数が大きいと複屈折性が低下するため、炭素数が２～６のアシル基が好ましい。また、ブチレートを形成するブチリル基は、直鎖であっても分岐していてもよい。 The acyl group may be linear or branched, or may form a ring. When the substitution degree of the acyl group is the same, birefringence decreases when the carbon number of the acyl group is large, and therefore an acyl group having 2 to 6 carbon atoms is preferable. Moreover, the butyryl group forming butyrate may be linear or branched.
　また、セルロースエステル系樹脂としては、単一のセルロースエステル系樹脂であってもよいし、また、複数種のセルロースエステル系樹脂、例えば、アシル基置換度の異なるもの等を組み合わせて用いてもよい。また、上記の好適範囲外のセルロースエステル系樹脂を組み合わせて用いてもよい。複数種のセルロースエステル系樹脂を組み合わせて用いることによって、所望の光学特性を有する透明性フィルム基材を得ることができる。上記の好適範囲外のセルロースエステル系樹脂を組み合わせて用いる場合であっても、好適範囲内のセルロースエステル系樹脂と好適範囲外のセルロースエステル系樹脂との混合比が、質量比で、１００：０～５０：５０であることが好ましい。 Further, as the cellulose ester resin, a single cellulose ester resin may be used, or a plurality of cellulose ester resins, for example, those having different degrees of acyl group substitution may be used in combination. . Moreover, you may use combining the cellulose-ester type resin outside said suitable range. By using a combination of a plurality of types of cellulose ester resins, a transparent film substrate having desired optical properties can be obtained. Even when a cellulose ester resin outside the above preferred range is used in combination, the mixing ratio between the cellulose ester resin within the preferred range and the cellulose ester resin outside the preferred range is 100: 0 by mass ratio. Preferably it is ˜50: 50.
　セルロースエステル系樹脂の原料であるセルロースとしては、特に限定はないが、綿花リンター、木材パルプ（針葉樹由来、広葉樹由来）、ケナフ等を挙げることができる。また、それらから得られたセルロースエステル系樹脂はそれぞれ任意の割合で混合使用することができる。これらのセルロースエステル系樹脂は、アシル化剤が酸無水物（無水酢酸、無水プロピオン酸、無水酪酸）である場合には、酢酸のような有機酸やメチレンクロライド等の有機溶媒を用い、硫酸のようなプロトン性触媒を用いてセルロース原料と反応させて得ることができる。 The cellulose that is a raw material of the cellulose ester resin is not particularly limited, and examples thereof include cotton linters, wood pulp (derived from coniferous trees and hardwoods), kenaf and the like. Moreover, the cellulose ester-type resin obtained from them can be mixed and used in arbitrary ratios, respectively. When the acylating agent is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride), these cellulose ester resins use an organic acid such as acetic acid or an organic solvent such as methylene chloride, It can be obtained by reacting with a cellulose raw material using such a protic catalyst.
　セルロースエステル系樹脂の数平均分子量は、６００００～３０００００であることが、光学補償フィルムに成型した場合の機械的強度が強い点で好ましい。また、溶液流延製膜法において適度なドープ粘度となる点からも好ましい。さらに、７００００～２０００００であることがより好ましい。また、重量平均分子量（Ｍｗ）／数平均分子量（Ｍｎ）が、１．４～４．５の範囲であることが好ましい。 The number average molecular weight of the cellulose ester-based resin is preferably 60000 to 300000 from the viewpoint of strong mechanical strength when molded into an optical compensation film. Moreover, it is preferable also from the point which becomes moderate dope viscosity in a solution casting film forming method. Further, it is more preferably 70000-200000. The weight average molecular weight (Mw) / number average molecular weight (Mn) is preferably in the range of 1.4 to 4.5.
　セルロースエステル系樹脂の重量平均分子量Ｍｗ、数平均分子量Ｍｎは、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）を用いて測定した。 The weight average molecular weight Mw and the number average molecular weight Mn of the cellulose ester-based resin were measured using gel permeation chromatography (GPC).
　また、セルロースエステル系樹脂は、単独で用いてもよいし、２種以上を組み合わせて用いてもよい。 In addition, the cellulose ester-based resin may be used alone or in combination of two or more.
　セルロースエステル系樹脂は、公知の方法により製造することができる。具体的には、アシル化剤が、酸クロライド（ＣＨ３ＣＯＣｌ、Ｃ２Ｈ５ＣＯＣｌ、Ｃ３Ｈ７ＣＯＣｌ）である場合には、触媒としてアミンのような塩基性化合物を用いて反応が行われる。より具体的には、特開平１０－４５８０４号公報に記載の方法等を参考にして合成することができる。また、セルロースエステル系樹脂は、各置換度に合わせて上記アシル化剤量を調整して反応させたものであり、セルロースエステル系樹脂はこれらアシル化剤がセルロース分子の水酸基に反応する。セルロース分子はグルコースユニットが多数連結したものからなっており、グルコースユニットに３個の水酸基がある。この３個の水酸基にアシル基が誘導された数を置換度（モル％）と言う。例えば、セルローストリアセテートはグルコースユニットの３個の水酸基全てにアセチル基が結合している（実際には２．６～３．０である）。 The cellulose ester resin can be produced by a known method. Specifically, when the acylating agent is an acid chloride (CH 3 COCl, C 2 H 5 COCl, C 3 H 7 COCl), the reaction is performed using a basic compound such as an amine as a catalyst. Is called. More specifically, it can be synthesized with reference to the method described in JP-A-10-45804. In addition, the cellulose ester-based resin is obtained by adjusting the amount of the acylating agent in accordance with the degree of substitution, and the cellulose ester-based resin reacts with the hydroxyl group of the cellulose molecule. Cellulose molecules are composed of many glucose units linked together, and the glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution (mol%). For example, cellulose triacetate has acetyl groups bonded to all three hydroxyl groups of the glucose unit (actually 2.6 to 3.0).
　また、セルロースエステルフィルムとしては、市販されているものとして、具体的に、例えば、コニカミノルタオプト株式会社製の、コニカミノルタタック　ＫＣ８ＵＸ、ＫＣ４ＵＸ、ＫＣ５ＵＸ、ＫＣ８ＵＣＲ３、ＫＣ８ＵＣＲ４、ＫＣ８ＵＣＲ５、ＫＣ８ＵＹ、ＫＣ４ＵＹ、ＫＣ１２ＵＲ、ＫＣ４ＵＥ、ＫＣ８ＵＥ、ＫＣ８ＵＹ－ＨＡ、ＫＣ８ＵＸ－ＲＨＡ、ＫＣ８ＵＸＷ－ＲＨＡ－Ｃ、ＫＣ８ＵＸＷ－ＲＨＡ－ＮＣ、ＫＣ４ＵＸＷ－ＲＨＡ－ＮＣ等が挙げられる。 Moreover, as a cellulose ester film, what is marketed, specifically, for example, Konica Minolta Op KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC12UR, manufactured by Konica Minolta Opto Co., Ltd. KC4UE, KC8UE, KC8UY-HA, KC8UX-RHA, KC8UXW-RHA-C, KC8UXW-RHA-NC, KC4UXW-RHA-NC, and the like.
　また、透明性フィルム基材としては、接合用中間層を形成する前に、表面処理を施したものが好ましい。表面処理としては、特に限定されず、通常の方法を採用することができる。具体的には、例えば、グロー放電処理、コロナ放電処理、紫外線処理、火炎処理等が挙げられる。 Further, as the transparent film base material, it is preferable to perform a surface treatment before forming the bonding intermediate layer. The surface treatment is not particularly limited, and a normal method can be employed. Specific examples include glow discharge treatment, corona discharge treatment, ultraviolet treatment, flame treatment, and the like.
　また、透明性フィルム基材としては、光学的に二軸性のフィルムであることが好ましい。ここで、光学的に二軸性のフィルムとは、ｎｘ＞ｎｙ＞ｎｚである透明性フィルム基材である。光学的に二軸性のフィルムとしては、可視光の透過率が８０％以上、膜厚が２０～７０μｍ、下記式（１）で求められる面内リタデーション（Ｒｏ）が２０～３３０ｎｍ、下記式（２）で求められる厚み方向リタデーション（Ｒｔ）が５０～３４０ｎｍであることが好ましい。
（１）　　　Ｒｏ＝（ｎｘ－ｎｙ）×ｄ
（２）　　　Ｒｔ＝｛（ｎｘ＋ｎｙ）／２－ｎｚ｝×ｄ
　ここで、ｎｘは、フィルムの面内の遅相軸方向の屈折率を示し、ｎｙは、フィルムの面内の遅相軸に直交する方向の屈折率を示し、ｎｚは、フィルムの厚み方向の屈折率を示し、ｄは、フィルムの厚み（ｎｍ）を示す。上記各屈折率は、例えば、王子計測機器株式会社製のＫＯＢＲＡ－２１ＡＤＨを用いて、温度２３℃、相対湿度５５％ＲＨの環境下で、波長５９０ｎｍで測定することができる。 The transparent film substrate is preferably an optically biaxial film. Here, the optically biaxial film is a transparent film substrate that satisfies nx>ny> nz. The optically biaxial film has a visible light transmittance of 80% or more, a film thickness of 20 to 70 μm, an in-plane retardation (Ro) determined by the following formula (1) of 20 to 330 nm, and the following formula ( The thickness direction retardation (Rt) obtained in 2) is preferably 50 to 340 nm.
(1) Ro = (nx−ny) × d
(2) Rt = {(nx + ny) / 2−nz} × d
Here, nx represents the refractive index in the slow axis direction in the plane of the film, ny represents the refractive index in the direction perpendicular to the slow axis in the plane of the film, and nz represents the thickness direction of the film. Refractive index is shown, d shows the thickness (nm) of a film. Each refractive index can be measured at a wavelength of 590 nm in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH using, for example, KOBRA-21ADH manufactured by Oji Scientific Instruments.
　また、セルロースエステルフィルムの二軸性を調整するためには、具体的には、例えば、リタデーション上昇剤、アクリル系重合体、及び糖エステル化合物の少なくとも１種を含有させることが好ましい。 In order to adjust the biaxiality of the cellulose ester film, specifically, for example, it is preferable to contain at least one of a retardation increasing agent, an acrylic polymer, and a sugar ester compound.
　リタデーション上昇剤としては、セルロースエステルフィルムのリタデーションを上昇させるものであれば、特に限定されない。 The retardation increasing agent is not particularly limited as long as it increases the retardation of the cellulose ester film.
　また、透明製フィルム基材を製造する際、その原料である樹脂組成物の硬化を阻害しない範囲で、微粒子、可塑剤や紫外線吸収剤が含有されているものであってもよい。また、このような透明性フィルム基材（樹脂フィルム）の製造方法についての詳細については、後述する。 Further, when a transparent film substrate is produced, it may contain fine particles, a plasticizer, and an ultraviolet absorber as long as it does not inhibit the curing of the resin composition that is the raw material. Moreover, the detail about the manufacturing method of such a transparent film base material (resin film) is mentioned later.
　透明性フィルム基材の厚みは、樹脂フィルムの薄型化を達成するため薄い方が好ましいが、製造中の破断等を防止するため、２０μｍ以上であることが好ましい。ここでの厚みとは、平均膜厚のことであり、株式会社ミツトヨ製の接触式膜厚計により、フィルムの幅方向に２０～２００箇所、膜厚を測定し、その測定値の平均値を膜厚として示す。また、透明性フィルム基材の幅、物性、及び形状等は、特に限定なく、製造する光学補償フィルムの目的に合わせて、適宜選択することができ、特に限定されないが、光学補償フィルムの幅は、大型の液晶表示装置への使用、偏光板加工時のフィルムの使用効率、生産効率の点から、１０００～４０００ｍｍであることが好ましい。 The thickness of the transparent film substrate is preferably thinner in order to achieve a thinner resin film, but is preferably 20 μm or more in order to prevent breakage during production. The thickness here means the average film thickness. The thickness is measured at 20 to 200 locations in the width direction of the film with a contact-type film thickness meter manufactured by Mitutoyo Corporation, and the average value of the measured values is calculated. Shown as film thickness. Further, the width, physical properties, and shape of the transparent film substrate are not particularly limited and can be appropriately selected according to the purpose of the optical compensation film to be manufactured. From the viewpoint of use in a large-sized liquid crystal display device, use efficiency of a film during polarizing plate processing, and production efficiency, the thickness is preferably 1000 to 4000 mm.
　透明性フィルム基材としては、光学補償フィルムの基材として用いることができるものであれば、特に限定されない。具体的には、例えば、溶液流延製膜法や溶融流延製膜法等によって得られた樹脂フィルム等を用いることができる。このような樹脂フィルムであれば、膜厚が均一であって、光学補償フィルムの基材として好適に使用できる。 The transparent film substrate is not particularly limited as long as it can be used as a substrate for an optical compensation film. Specifically, for example, a resin film obtained by a solution casting film forming method or a melt casting film forming method can be used. If it is such a resin film, a film thickness is uniform and it can be conveniently used as a base material of an optical compensation film.
　本発明においては、セルロースエステル系樹脂透明性フィルム基材が、セルロースアセテートプロピオネート樹脂フィルムであることが好ましい。このような構成によれば、透明性フィルム基材の透明性が高く、さらに、光学異方性層に含有される液晶化合物の配向性が高いので、光学補償性能に優れるだけではなく、透明性にも充分に優れた光学補償フィルムが得られる。
（光学異方性層）
　光学異方性層は、液晶化合物を含有する層であれば、特に限定されず、視野角を拡大する等の所定の光学補償性能を発揮できる光学異方性層等が挙げられる。また、光学異方性層は、液晶化合物が配向されていることが好ましく、その配向性が高いことがより好ましい。 In the present invention, the cellulose ester resin transparent film substrate is preferably a cellulose acetate propionate resin film. According to such a configuration, since the transparency of the transparent film substrate is high, and the orientation of the liquid crystal compound contained in the optical anisotropic layer is high, not only the optical compensation performance is excellent, but also the transparency. In addition, a sufficiently excellent optical compensation film can be obtained.
(Optically anisotropic layer)
The optically anisotropic layer is not particularly limited as long as it contains a liquid crystal compound, and examples thereof include an optically anisotropic layer that can exhibit predetermined optical compensation performance such as widening the viewing angle. In the optically anisotropic layer, the liquid crystal compound is preferably aligned, and the alignment property is more preferable.
　また、液晶化合物としては、特に限定されず、光学異方性層に含有される従来公知の液晶化合物等が挙げられる。具体的には、例えば、分子内に棒状のメソゲン基や円盤状のメソゲン基を有するもの等が挙げられる。この中でも、分子内に棒状のメソゲン基を有するものが好ましい。そして、液晶化合物としては、垂直配向でき、その配向を固定化することができる、いわゆる垂直配向性を有する液晶化合物であることがより好ましい。すなわち、光学異方性層としては、例えば、分子内に棒状のメソゲン基を有する液晶化合物を含有し、メソゲン基が、その長軸方向を透明性フィルム基材の面方向に略垂直となるように配向（垂直配向）させた後、配向が固定化されているものが好ましい。 In addition, the liquid crystal compound is not particularly limited, and examples thereof include conventionally known liquid crystal compounds contained in the optically anisotropic layer. Specifically, for example, those having a rod-like mesogen group or a disk-like mesogen group in the molecule can be mentioned. Among these, those having a rod-like mesogenic group in the molecule are preferable. The liquid crystal compound is more preferably a liquid crystal compound having so-called vertical alignment, which can be vertically aligned and the alignment can be fixed. That is, the optically anisotropic layer contains, for example, a liquid crystal compound having a rod-shaped mesogenic group in the molecule, and the mesogenic group has a major axis direction substantially perpendicular to the surface direction of the transparent film substrate. It is preferable that the orientation is fixed after being oriented (vertical orientation).
　また、液晶化合物が、分子内に棒状のメソゲン基を有し、メソゲン基が、その長軸方向を透明性フィルム基材の面方向に略垂直となるように配向させた後、配向が固定化されていることが好ましい。このような構成によれば、光学補償性能のより優れた光学フィルムが得られる。 In addition, the liquid crystal compound has a rod-shaped mesogenic group in the molecule, and the orientation is fixed after the mesogenic group is oriented so that its major axis direction is substantially perpendicular to the surface direction of the transparent film substrate. It is preferable that According to such a configuration, an optical film having better optical compensation performance can be obtained.
　また、分子内に棒状のメソゲン基を有する液晶化合物としては、棒状のメソゲン基と重合性官能基とを含有する重合性液晶であってもよいし、少なくとも主鎖及び側鎖のいずれか一方に棒状のメソゲン基を含有する高分子液晶であってもよいし、棒状のメソゲン基と重合性官能基とを含有する高分子液晶であってもよい。重合性官能基を含有することによって、固定化の際、例えば、液晶転移温度未満まで冷却した後、冷却しながら、重合させることによって、配向をより固定化させることができ、さらに、光学異方性層として硬化させることもできる点等から好ましい。そして、メソゲン基の配向性や重合による光学異方性層の成形性等の観点から、重合性液晶が好ましい。 The liquid crystal compound having a rod-shaped mesogen group in the molecule may be a polymerizable liquid crystal containing a rod-shaped mesogen group and a polymerizable functional group, and at least one of the main chain and the side chain. It may be a polymer liquid crystal containing a rod-shaped mesogen group or a polymer liquid crystal containing a rod-shaped mesogen group and a polymerizable functional group. By containing a polymerizable functional group, the alignment can be further fixed by, for example, cooling to a temperature lower than the liquid crystal transition temperature and then polymerizing while cooling. From the point etc. which can be hardened as an adhesive layer. In view of the orientation of the mesogenic group and the moldability of the optically anisotropic layer by polymerization, a polymerizable liquid crystal is preferable.
　メソゲン基としては、特に限定されないが、垂直配向しうる棒状のメソゲン基であることが好ましい。具体的には、例えば、エステル基、シアノ基、アルキル基、及びアリール基を含有する官能基等が挙げられる。また、メソゲン基としては、上記各メソゲン基を１種含有するものであってもよいし、２種以上を組み合わせて含有するものであってもよい。 The mesogenic group is not particularly limited, but is preferably a rod-shaped mesogenic group that can be vertically aligned. Specific examples include functional groups containing an ester group, a cyano group, an alkyl group, and an aryl group. Moreover, as a mesogenic group, the said mesogenic group may be contained 1 type, and it may contain in combination of 2 or more types.
　重合性官能基としては、特に限定されず、配向後、配向を保持したまま重合させることができることが好ましい。具体的には、例えば、熱によって重合が開始するものであってもよいし、紫外線等の活性線の照射によって重合が開始するものであってもよい。すなわち、重合性液晶の場合、熱硬化性のものであってもよいし、活性線硬化性のものであってもよい。また、液晶化合物を液晶転移温度未満で重合させる場合、あまり加熱しない方が好ましいので、活性線硬化性のものの方がより好ましい。 The polymerizable functional group is not particularly limited, and it is preferable that polymerization can be performed while maintaining the orientation after the orientation. Specifically, for example, the polymerization may be initiated by heat, or the polymerization may be initiated by irradiation with active rays such as ultraviolet rays. That is, in the case of the polymerizable liquid crystal, it may be thermosetting or actinic ray curable. In addition, when the liquid crystal compound is polymerized at a temperature lower than the liquid crystal transition temperature, it is preferable that the liquid crystal compound is not heated so much that the active ray curable one is more preferable.
　また、液晶化合物が、活性線の照射により重合可能な官能基を有する重合性液晶化合物であって、固定化工程が、光学異方性層形成用塗布組成物を冷却した後、光学異方性層形成用塗布組成物に活性線を照射して、光学異方性層形成用塗布組成物を硬化させる工程であることが好ましい。 In addition, the liquid crystal compound is a polymerizable liquid crystal compound having a functional group that can be polymerized by irradiation with actinic radiation, and the immobilization step cools the coating composition for forming the optical anisotropic layer, and then the optical anisotropy. The layer forming coating composition is preferably a step of irradiating an active ray to cure the optically anisotropic layer forming coating composition.
　このような構成によれば、後述する接合用中間層、及び光学異方性層において欠陥の発生を抑制でき、接合用中間層と光学異方性層との密着性が充分に高く、さらに、光学異方性層の液晶化合物の配向性が充分に高い光学補償フィルムをより容易に製造することができる。 According to such a configuration, it is possible to suppress the occurrence of defects in the bonding intermediate layer and the optically anisotropic layer described later, the adhesion between the bonding intermediate layer and the optically anisotropic layer is sufficiently high, An optical compensation film having a sufficiently high orientation of the liquid crystal compound in the optically anisotropic layer can be more easily produced.
　また、重合性官能基としては、具体的には、例えば、アクリロイル基、メタクリロイル基やビニルエーテル等のビニル基、エポキシ基、及びオキセタニル基等が挙げられる。また、重合性官能基を単独で用いてもよいし、２種以上を組み合わせて用いてもよい。また、重合性液晶としては、重合性官能基を分子内に１つ含有するものであってもよいし、２つ以上含有するものであってもよい。 Specific examples of the polymerizable functional group include a vinyl group such as acryloyl group, methacryloyl group and vinyl ether, an epoxy group, and an oxetanyl group. Moreover, a polymerizable functional group may be used independently and may be used in combination of 2 or more type. The polymerizable liquid crystal may contain one polymerizable functional group in the molecule, or may contain two or more.
　液晶化合物としては、メソゲン基を含有するものやメソゲン基と重合性官能基とを含有するもの等が挙げられる。具体的には、例えば、Ｍａｋｒｏｍｏｌ．Ｃｈｅｍ．，１９０巻、２２５５頁（１９８９年）、Ａｄｖａｎｃｅｄ　Ｍａｔｅｒｉａｌｓ　５巻、１０７頁（１９９３年）、米国特許第４６８３３２７号明細書、米国特許第５６２２６４８号明細書、米国特許第５７７０１０７号明細書、国際公開第９５／２２５８６号公報、国際公開第９５／２４４５５号公報、国際公開第９７／００６００号公報、国際公開第９８／２３５８０号公報、国際公開第９８／５２９０５号公報、特開平１－２７２５５１号公報、特開平６－１６６１６号公報、特開平７－１１０４６９号公報、特開平１１－８００８１号公報、特開２００１－３２８９７３号公報、特開２００４－２４０１８８号公報、特開２００５－９９２３６号公報、特開２００５－９９２３７号公報、特開２００５－１２１８２７号公報、特開２００２－３００４２号公報等に記載の化合物等が挙げられる。また、より具体的には、例えば、下記化学式（１）及び下記化学式（２）で表される化合物が好ましく用いられる。 Examples of the liquid crystal compound include those containing a mesogenic group and those containing a mesogenic group and a polymerizable functional group. Specifically, for example, Makromol. Chem. 190, 2255 (1989), Advanced Materials, 5, 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, International Publication No. No. 95/22586, WO 95/24455, WO 97/00600, WO 98/23580, WO 98/52905, JP-A 1-272551, JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, JP-A 2001-328773, JP-A 2004-240188, JP-A 2005-99236, JP JP 2005-99237 A, JP 2005-121827 A, JP It includes the compounds described in 002-30042 JP like. More specifically, for example, compounds represented by the following chemical formula (1) and the following chemical formula (2) are preferably used.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　式中、Ｒ１ 及びＲ２ は、それぞれ独立して水素又はメチル基を示し、Ｘは、水素、塩素、臭素、ヨウ素、炭素数１～４のアルキル基、メトキシ基、シアノ基、又はニトロ基を示し、ａ及びｂは、２～１２を示す。 In the formula, R 1 and R 2 each independently represent hydrogen or a methyl group, and X represents hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, or a nitro group. A and b are 2 to 12.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　式中、Ｒ３は、水素又はメチル基を示す。 In the formula, R 3 represents hydrogen or a methyl group.
　また、上記化学式（１）で表される液晶化合物としては、Ｒ１及びＲ２が、共に水素を示すものが、液晶相を示す温度範囲が広い点から好ましい。また、Ｘとしては、塩素又はメチル基が好ましい。ａ及びｂは、２～１２を示すが、４～１０であることが好ましく、６～９であることが好ましい。 In addition, as the liquid crystal compound represented by the chemical formula (1), it is preferable that R 1 and R 2 both represent hydrogen from the viewpoint of a wide temperature range indicating a liquid crystal phase. X is preferably a chlorine or methyl group. a and b each represent 2 to 12, preferably 4 to 10, and more preferably 6 to 9.
　また、液晶化合物は、上記各液晶化合物を単独で用いてもよいし、２種以上組み合わせて用いてもよい。 Further, as the liquid crystal compound, the above liquid crystal compounds may be used alone or in combination of two or more.
　また、液晶化合物としては、市販されているものとして、具体的には、例えば、ＤＩＣ株式会社製のＵＣＬ０１８や、ＢＡＳＦ社製のパリオカラーＬＣ２４２等が挙げられる。 Moreover, as a liquid crystal compound, as a commercially available product, specifically, for example, UCL018 manufactured by DIC Corporation, Paliocolor LC242 manufactured by BASF Corporation, and the like can be given.
　なおここで、垂直配向とは、透明性フィルム基材の厚み方向に対する、メソゲン基の長軸方向（液晶化合物の配向方向）の角度であるチルト角が、７０～９０°であることを意味し、８０～９０°であることが好ましい。また、液晶化合物が垂直配向するか否かは、液晶化合物、特にその棒状のメソゲン基の構造に依存することが知られている。すなわち、垂直配向する構造を有する液晶化合物であれば、公知の配向処理によって、垂直配向しうる。 Here, the vertical alignment means that the tilt angle, which is the angle of the major axis direction of the mesogenic group (the alignment direction of the liquid crystal compound) with respect to the thickness direction of the transparent film substrate, is 70 to 90 °. 80 to 90 ° is preferable. Further, it is known that whether or not the liquid crystal compound is vertically aligned depends on the structure of the liquid crystal compound, particularly its rod-shaped mesogen group. That is, a liquid crystal compound having a vertically aligned structure can be vertically aligned by a known alignment process.
　配向処理としては、具体的には、例えば、被塗布層である接合用中間層等の上に塗布された、液晶化合物を含む光学異方性層形成用塗布組成物（塗布液）を、液晶化合物の液晶転移温度以上まで加熱することによって、垂直配向させ、その後、液晶転移温度未満まで冷却することによって、その垂直配向を固定化する方法等が挙げられる。ここで、液晶転移温度とは、固体－液晶相転移温度を指す。そして、光学異方性層形成用塗布組成物を塗布した後の液晶転移温度以上までの加熱は、液晶－等方性液体相転移温度以下までであることが好ましい。 Specifically, as the alignment treatment, for example, a coating composition (coating liquid) for forming an optically anisotropic layer containing a liquid crystal compound, which is applied on a bonding intermediate layer or the like which is a coating layer, is applied to a liquid crystal. For example, a method of fixing the vertical alignment by heating the compound to a liquid crystal transition temperature or higher to cause vertical alignment and then cooling to a temperature lower than the liquid crystal transition temperature. Here, the liquid crystal transition temperature refers to a solid-liquid crystal phase transition temperature. The heating up to the liquid crystal transition temperature or higher after coating the coating composition for forming an optically anisotropic layer is preferably up to the liquid crystal-isotropic liquid phase transition temperature or lower.
　また、光学異方性層の厚みは、０．１～１０μｍであることが好ましく、０．２～５μｍであることがより好ましい。 Further, the thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, and more preferably 0.2 to 5 μm.
　また、光学異方性層は、上記式（１）で求められる面内リタデーション（Ｒｏ）が、０～１０ｎｍであることが好ましい。また、上記式（２）で求められる厚み方向リタデーション（Ｒｔ）が、－５００～－１００ｎｍであることが好ましい。
（接合用中間層）
　接合用中間層は、透明性フィルム基材上、又は下地層を備える場合には、下地層上に形成される。 The optically anisotropic layer preferably has an in-plane retardation (Ro) determined by the above formula (1) of 0 to 10 nm. Further, the thickness direction retardation (Rt) determined by the above formula (2) is preferably −500 to −100 nm.
(Interlayer for bonding)
The bonding intermediate layer is formed on the transparent film base material or on the base layer when the base layer is provided.
　また、接合用中間層は、活性線硬化樹脂を含む。また、接合用中間層は、光学異方性層の液晶化合物の配向を促進させる液晶配向層として働くもの、具体的には、例えば、ラビング処理を施したものであってもよい。 Also, the bonding intermediate layer includes an actinic radiation curable resin. Further, the bonding intermediate layer may function as a liquid crystal alignment layer that promotes alignment of the liquid crystal compound of the optically anisotropic layer, specifically, for example, a layer subjected to rubbing treatment.
　活性線硬化樹脂としては、紫外線等の活性線によって硬化するものであって、透明性があるものである。ここで透明性があるとは、可視光の透過率が６０％以上であることであり、好ましくは８０％以上、より好ましくは９０％以上である。具体的には、例えば、ビニル基、アリル基、アクリロイル基、メタクリロイル基、イソプロペニル基、エポキシ基、及びオキセタニル基等の重合性官能基を有するもの等が挙げられる。また、活性線硬化樹脂としては、重合性官能基を２つ以上有し、活性線を照射することによって、架橋構造又は網目構造となるものが好ましい。また、活性線としては、作業性の観点等から、紫外線であることが好ましい。すなわち、活性線硬化樹脂としては、紫外線硬化樹脂であることが好ましい。また、活性線硬化樹脂としては、活性線硬化性化合物を硬化させて得られるものであることが好ましい。そして、その活性線硬化性化合物としては、ウレタンアクリレートオリゴマー及びアクリレートオリゴマーの少なくともいずれか一方であることがより好ましい。 The actinic radiation curable resin is curable by actinic radiation such as ultraviolet rays and has transparency. Here, having transparency means that the transmittance of visible light is 60% or more, preferably 80% or more, and more preferably 90% or more. Specific examples include those having a polymerizable functional group such as a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, an isopropenyl group, an epoxy group, and an oxetanyl group. Moreover, as actinic radiation curable resin, what has two or more polymeric functional groups and becomes a crosslinked structure or network structure by irradiating actinic radiation is preferable. The active ray is preferably ultraviolet rays from the viewpoint of workability. That is, the actinic radiation curable resin is preferably an ultraviolet curable resin. The actinic radiation curable resin is preferably obtained by curing an actinic radiation curable compound. The actinic radiation curable compound is more preferably at least one of a urethane acrylate oligomer and an acrylate oligomer.
　活性線硬化樹脂としては、具体的には、例えば、紫外線硬化型ウレタンアクリレート系樹脂、紫外線硬化型ポリエステルアクリレート系樹脂、紫外線硬化型エポキシアクリレート系樹脂、紫外線硬化型ポリオールアクリレート系樹脂、及び紫外線硬化型エポキシ樹脂等の紫外線硬化型アクリレート系樹脂等が挙げられる。 Specific examples of the actinic radiation curable resin include an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet curable resin. Examples thereof include ultraviolet curable acrylate resins such as epoxy resins.
　紫外線硬化型ウレタンアクリレート系樹脂としては、具体的には、例えば、ポリエステルポリオールに、イソシアネートモノマー又はプレポリマーを反応させて得られた生成物を、さらに２－ヒドロキシエチルアクリレート、２－ヒドロキシエチルメタクリレート（以下、アクリレートにはメタクリレートを包含するものとして、アクリレートのみを表示する）、２－ヒドロキシプロピルアクリレート等の水酸基を有するアクリレート系モノマーを反応させることによって容易に得ることができるもの等が挙げられる。より具体的には、例えば、特開昭５９－１５１１１０号公報に記載のもの等が挙げられる。また、市販品としては、具体的には、例えば、日本合成化学工業株式会社製の紫光ＵＶ－７５１０Ｂ、ＤＩＣ株式会社製のユニディック１７－８０６　１００部と日本ポリウレタン工業株式会社製のコロネートＬ　１部との混合物等が挙げられる。 Specific examples of the ultraviolet curable urethane acrylate resin include, for example, products obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate ( Hereinafter, acrylates include those containing methacrylates, and only those acrylates are indicated), and those that can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. More specifically, examples include those described in JP-A No. 59-151110. Further, as commercially available products, specifically, for example, purple light UV-7510B manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 100 parts of Unidic 17-806 manufactured by DIC Corporation, and Coronate L 1 manufactured by Nippon Polyurethane Industry Co., Ltd. The mixture with a part etc. are mentioned.
　紫外線硬化型ポリエステルアクリレート系樹脂としては、具体的には、例えば、ポリエステルポリオールに、２－ヒドロキシエチルアクリレート、２－ヒドロキシアクリレート系のアクリレート系モノマーを反応させることによって容易に得ることができるもの等が挙げられる。より具体的には、例えば、特開昭５９－１５１１１２号公報に記載のもの等が挙げられる。 Specific examples of the UV curable polyester acrylate resin include those that can be easily obtained by reacting polyester polyol with 2-hydroxyethyl acrylate or 2-hydroxy acrylate acrylate monomer. Can be mentioned. More specifically, examples include those described in JP-A-59-151112.
　紫外線硬化型エポキシアクリレート系樹脂としては、具体的には、例えば、エポキシアクリレートをオリゴマーとし、これに反応性希釈剤、光重合開始剤を添加し、反応させて生成するもの等が挙げられる。より具体的には、例えば、特開平１－１０５７３８号公報に記載のもの等が挙げられる。 Specific examples of the ultraviolet curable epoxy acrylate resin include those produced by reacting an epoxy acrylate with an oligomer, a reactive diluent and a photopolymerization initiator added thereto. More specifically, examples include those described in JP-A-1-105738.
　紫外線硬化型ポリオールアクリレート系樹脂としては、具体的には、例えば、トリメチロールプロパントリアクリレート、ジトリメチロールプロパンテトラアクリレート、ペンタエリスリトールトリアクリレート、ペンタエリスリトールテトラアクリレート、ジペンタエリスリトールヘキサアクリレート、アルキル変性ジペンタエリスリトールペンタアクリレート等が挙げられる。 Specific examples of ultraviolet curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and alkyl-modified dipentaerythritol. Examples include pentaacrylate.
　活性線硬化樹脂としては、上記例示した化合物のほかに、メチルアクリレート、エチルアクリレート、ブチルアクリレート、ベンジルアクリレート、シクロヘキシルアクリレート、エチレングリコールジアクリレート、プロピレングリコールジアクリレート、ジビニルベンゼン、１，４－シクロヘキサンジアクリレート、１，４－シクロヘキシルジメチルアジアクリレート、トリメチロールプロパントリアクリレート、及びペンタエリスリトールテトラアクリルエステル等が挙げられる。そして、その市販品としては、具体的には、例えば、株式会社ＡＤＥＫＡ製の、アデカオプトマーＫＲ・ＢＹシリーズ（ＫＲ－４００、ＫＲ－４１０、ＫＲ－５５０、ＫＲ－５６６、ＫＲ－５６７、ＢＹ－３２０Ｂ）、広栄化学化学工業株式会社製の、コーエイハードＡ－１０１－ＫＫ、Ａ－１０１－ＷＳ、Ｃ－３０２、Ｃ－４０１－Ｎ、Ｃ－５０１、Ｍ－１０１、Ｍ－１０２、Ｔ－１０２、Ｄ－１０２、ＮＳ－１０１、ＦＴ－１０２Ｑ８、ＭＡＧ－１－Ｐ２０、ＡＧ－１０６、Ｍ－１０１－Ｃ、大日精化工業株式会社製の、セイカビームＰＨＣ２２１０（Ｓ）、ＰＨＣＸ－９（Ｋ－３）、ＰＨＣ２２１３、ＤＰ－１０、ＤＰ－２０、ＤＰ－３０、Ｐ１０００、Ｐ１１００、Ｐ１２００、Ｐ１３００、Ｐ１４００、Ｐ１５００、Ｐ１６００、ＳＣＲ９００、ダイセル・サイテック株式会社製の、ＫＲＭ７０３３、ＫＲＭ７０３９、ＫＲＭ７１３０、ＫＲＭ７１３１、ＵＶＥＣＲＹＬ２９２０１、ＵＶＥＣＲＹＬ２９２０２、ＤＩＣ株式会社製の、ＲＣ－５０１５、ＲＣ－５０１６、ＲＣ－５０２０、ＲＣ－５０３１、ＲＣ－５１００、ＲＣ－５１０２、ＲＣ－５１２０、ＲＣ－５１２２、ＲＣ－５１５２、ＲＣ－５１７１、ＲＣ－５１８０、ＲＣ－５１８１、中国塗料株式会社製の、オーレックスＮｏ．３４０クリヤ、三洋化成工業株式会社製の、サンラッドＨ－６０１、ＲＣ－７５０、ＲＣ－７００、ＲＣ－６００、ＲＣ－５００、ＲＣ－６１１、ＲＣ－６１２、昭和高分子株式会社製の、ＳＰ－１５０９、ＳＰ－１５０７、グレース・ジャパン株式会社製のＲＣＣ－１５Ｃ、東亞合成株式会社製の、アロニックスＭ－６１００、Ｍ－８０３０、Ｍ－８０６０、新中村化学工業株式会社製の、ＮＫハードＢ－４２０、ＮＫエステルＡ－ＤＯＧ、ＮＫエステルＡ－ＩＢＤ－２Ｅ等が挙げられる。 In addition to the compounds exemplified above, the active ray curable resin includes methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate. 1,4-cyclohexyldimethyladiacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylic ester, and the like. Specific examples of such commercially available products include, for example, Adekaoptomer KR / BY series (KR-400, KR-410, KR-550, KR-566, KR-567, BY, manufactured by ADEKA Corporation). -320B), KOHEI HARD A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T -102, D-102, NS-101, FT-102Q8, MAG-1-P20, AG-106, M-101-C, Seika Beam PHC2210 (S), PHCX-9 (manufactured by Dainichi Seika Kogyo Co., Ltd.) K-3), PHC2213, DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, CR900, manufactured by Daicel-Cytech Co., Ltd., KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202, manufactured by DIC Corporation, RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC- 5102, RC-5120, RC-5122, RC-5152, RC-5171, RC-5180, RC-5181, manufactured by China Paint Co., Ltd. 340 Clear, Sanyo Chemical Industries, Ltd., Sun-Rad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612, Showa Polymer Co., Ltd., SP- 1509, SP-1507, RCC-15C manufactured by Grace Japan KK, Aronix M-6100, M-8030, M-8060 manufactured by Toagosei Co., Ltd., NK Hard B- manufactured by Shin-Nakamura Chemical Co., Ltd. 420, NK ester A-DOG, NK ester A-IBD-2E, and the like.
　また、接合用中間層の厚みが、０．０１～１μｍであることが好ましく、０．０２～０．７μｍであることがより好ましい。接合用中間層の厚みが薄すぎると、接合用中間層が有する効果、例えば、液晶配向層、帯電防止層、溶出防止層及び防眩層等として働く効果や、上記のような密着性を高める効果を発揮しにくくなる傾向がある。また、接合用中間層の厚みが厚すぎると、得られる光学補償フィルムが不必要に厚くなり、光学補償フィルムの薄型化を阻害するという傾向がある。 Further, the thickness of the bonding intermediate layer is preferably 0.01 to 1 μm, and more preferably 0.02 to 0.7 μm. If the thickness of the bonding intermediate layer is too thin, the bonding intermediate layer has an effect such as a liquid crystal alignment layer, an antistatic layer, an elution preventing layer, an antiglare layer, or the like, and the above-described adhesion is enhanced. There is a tendency that it becomes difficult to exert the effect. Moreover, when the thickness of the joining intermediate layer is too thick, the obtained optical compensation film becomes unnecessarily thick, and there is a tendency that the thinning of the optical compensation film is hindered.
　このような構成によれば、接合用中間層及び光学異方性層において欠陥の発生をより抑制でき、接合用中間層と光学異方性層との密着性がより高く、さらに、光学異方性層の液晶化合物の配向性がより高い光学補償フィルムが得られる。 According to such a configuration, generation of defects in the bonding intermediate layer and the optically anisotropic layer can be further suppressed, adhesion between the bonding intermediate layer and the optically anisotropic layer is higher, and optical anisotropy is further achieved. An optical compensation film having a higher orientation of the liquid crystal compound in the conductive layer is obtained.
　また、活性線硬化樹脂が、活性線硬化性化合物を硬化させて得られるものであることが好ましい。そして、その活性線硬化性化合物としては、ウレタンアクリレートオリゴマー及びアクリレートオリゴマーの少なくともいずれか一方であることがより好ましい。
（バックコート層）
　本発明では、セルロースエステル系樹脂透明性フィルム基材の光学異方性層を設けた側の面と反対側の面にはバックコート層が設けられている。 The actinic radiation curable resin is preferably obtained by curing an actinic radiation curable compound. The actinic radiation curable compound is more preferably at least one of a urethane acrylate oligomer and an acrylate oligomer.
(Back coat layer)
In this invention, the backcoat layer is provided in the surface on the opposite side to the surface in which the optically anisotropic layer was provided of the cellulose-ester-type resin transparent film base material.
　ここで、バックコート層は、ブロッキング防止層を兼ねて塗設され、その場合、バックコート層形成用塗布組成物には、ブロッキング防止機能を持たせるために微粒子が添加されている。 Here, the back coat layer is also applied as an anti-blocking layer, and in this case, fine particles are added to the coating composition for forming the back coat layer in order to provide an anti-blocking function.
　なお、バックコート層は、活性エネルギー線硬化樹脂層やその他の層を設けることで生じるカールを矯正するためにも設けられている。すなわち、光学補償フィルムに、バックコート層を設けた面を内側にして丸まろうとする性質を持たせることにより、カールの度合いをバランスさせることができる。 The back coat layer is also provided for correcting curling caused by providing the active energy ray-curable resin layer and other layers. That is, the degree of curling can be balanced by giving the optical compensation film the property of being rounded with the surface on which the backcoat layer is provided inside.
　バックコート層に添加される微粒子としては、無機化合物の例として、二酸化珪素、二酸化チタン、酸化アルミニウム、酸化ジルコニウム、炭酸カルシウム、炭酸カルシウム、タルク、クレイ、焼成カオリン、焼成ケイ酸カルシウム、酸化錫、酸化インジウム、酸化亜鉛、ＩＴＯ、水和ケイ酸カルシウム、ケイ酸アルミニウム、ケイ酸マグネシウム及びリン酸カルシウムを挙げることができる。微粒子は珪素を含むものがヘイズが低くなる点で好ましく、特に二酸化珪素が好ましい。 As fine particles added to the back coat layer, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, Mention may be made of indium oxide, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles containing silicon are preferable in terms of low haze, and silicon dioxide is particularly preferable.
　これらの微粒子は、例えばアエロジルＲ９７２、Ｒ９７２Ｖ、Ｒ９７４、Ｒ８１２、２００、２００Ｖ、３００、Ｒ２０２、ＯＸ５０、ＴＴ６００（以上、日本アエロジル株式会社製）、シーホスターＫＥ－Ｐ１０、同ＫＥ－Ｐ３０、同ＫＥ－Ｐ５０、同ＫＥ－Ｐ１００、同ＫＥ－Ｐ１５０、同ＫＥ－Ｐ２５０（以上、株式会日本触媒社製）の商品名で市販されており、を使用することができる。これらの中でも、特に好ましいものとしては、シーホスターＫＥ－Ｐ３０、同ＫＥ－Ｐ５０、同ＫＥ－Ｐ１００が挙げられる。 These fine particles are, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above, manufactured by Nippon Aerosil Co., Ltd.), Seahoster KE-P10, KE-P30, KE-P50. KE-P100, KE-P150, and KE-P250 (above, manufactured by Nippon Shokubai Co., Ltd.) can be used. Among these, particularly preferred are Seahoster KE-P30, KE-P50, and KE-P100.
　酸化ジルコニウムの微粒子は、例えばアエロジルＲ９７６及びＲ８１１（以上、日本アエロジル株式会社製）の商品名で市販されており、使用することができる。 Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.), and can be used.
　ポリマーの微粒子の例として、アクリル樹脂微粒子、シリコーン樹脂微粒子、及びフッ素樹脂微粒子を挙げることができる。アクリル樹脂微粒子としては、例えばＭＰ－１４５１（綜研化学株式会社製）、リオスフェアＲＳＰ－３０２１Ｄ（東洋インキ株式会社製）の商品名で市販されており、使用することができる。 Examples of polymer fine particles include acrylic resin fine particles, silicone resin fine particles, and fluororesin fine particles. The acrylic resin fine particles are commercially available under the trade names of MP-1451 (manufactured by Soken Chemical Co., Ltd.) and Riosphere RSP-3021D (manufactured by Toyo Ink Co., Ltd.), and can be used.
　また、シリコーン樹脂微粒子としては、特に三次元の網状構造を有するものが好ましく、例えばトスパール１０３、同１０５、同１０８、同１２０、同１４５、同３１２０及び同２４０（以上、東芝シリコーン株式会社製）の商品名で市販されており、使用することができる。 Further, as the silicone resin fine particles, those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120 and 240 (above, manufactured by Toshiba Silicone Co., Ltd.) It is marketed under the trade name of and can be used.
　バックコート層に含まれる微粒子は、その粒径が１μｍ以下である。また、バックコート層に含まれる微粒子は、バインダーに対して０．１～５０質量％好ましくは０．１～１０質量％であることが好ましい。バックコート層を設けた場合のヘイズの増加は１％以下であることが好ましく０．５％以下であることが好ましく、特に０．０～０．１％であることが好ましい。なお、バックコート層に含まれる微粒子の粒径は可視光域の凡その下限である４００ｎｍ以下がより好ましい。光学的に波長以下の粒径では散乱が生じにくくなるからである。 The fine particles contained in the backcoat layer have a particle size of 1 μm or less. The fine particles contained in the backcoat layer are 0.1 to 50% by mass, preferably 0.1 to 10% by mass, based on the binder. When the back coat layer is provided, the increase in haze is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.0 to 0.1%. The particle size of the fine particles contained in the backcoat layer is more preferably 400 nm or less, which is the approximate lower limit of the visible light region. This is because scattering hardly occurs when the particle diameter is optically smaller than the wavelength.
　バックコート層のバインダーとして用いられる樹脂としては、例えばセルロースアセテートプロピオネート（好ましくはアセチル基置換度１．２～２．３、プロピオニル基置換度０．１～１．０）、ジアセチルセルロース、セルロースアセテートブチレート樹脂等のセルロースエステル系樹脂を挙げることができるが、これらに限定されるものではない。 Examples of the resin used as the binder of the back coat layer include cellulose acetate propionate (preferably acetyl group substitution degree 1.2 to 2.3, propionyl group substitution degree 0.1 to 1.0), diacetyl cellulose, cellulose Examples thereof include, but are not limited to, cellulose ester resins such as acetate butyrate resin.
　特に好ましくはジアセチルセルロース、トリアセチルセルロース、セルロースアセテートプロピオネート、セルロースアセテートブチレートのようなセルロース系樹脂である。 Particularly preferred are cellulose resins such as diacetyl cellulose, triacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate.
　バックコート層は、具体的には、上記微粒子、バインダー、およびセルロースエステル系樹脂透明性フィルム基材を溶解させる溶媒または膨潤させる溶媒、およびフィルム基材を溶解させない溶媒を含むバックコート層形成用塗布組成物を、セルロースエステル系樹脂透明性フィルム基材塗布することによって行なわれる。 Specifically, the back coat layer is a coating for forming a back coat layer containing the fine particles, the binder, and a solvent that dissolves or swells the cellulose ester resin transparent film substrate, and a solvent that does not dissolve the film substrate. The composition is performed by applying a cellulose ester resin transparent film substrate to the composition.
　ここで、バックコート層形成用塗布組成物には、２種類の混合溶剤を使用するのが、好ましい。 Here, it is preferable to use two kinds of mixed solvents for the coating composition for forming the backcoat layer.
　ただし、これら２種類の溶剤は、下記の２つの条件を満たすものである。 However, these two types of solvents satisfy the following two conditions.
　ここで、ＳＰ値９～１０の溶剤を「溶剤１」、およびＳＰ値１１～１５の溶剤を「溶剤２」とすると、これらの溶剤は、下記の２つの条件を満たす。 Here, assuming that the solvent having an SP value of 9 to 10 is “solvent 1” and the solvent having an SP value of 11 to 15 is “solvent 2”, these solvents satisfy the following two conditions.
　条件１：溶剤１の沸点＞溶剤２の沸点
　条件２：溶剤１と溶剤の混合割合比が、８：２～１：９
　ここで、有機化合物のＳＰ値とは、溶解性パラメーターのことであって、どれだけ溶媒などに溶けやすいかということを数値化したものであり、有機化合物ではよく使われる極性と同義で、このＳＰ値が大きい程、極性が大きいことを表わす。ＳＰ値は、Ｆｅｄｏｒｓ法で計算した計算値を使用することができる。 Condition 1: Boiling point of solvent 1> Boiling point of solvent 2 Condition 2: Mixing ratio of solvent 1 and solvent is 8: 2 to 1: 9
Here, the SP value of an organic compound is a solubility parameter, which is a numerical value of how easily it is soluble in a solvent, etc., and is synonymous with the polarity often used in organic compounds. The greater the SP value, the greater the polarity. As the SP value, a value calculated by the Fedors method can be used.
　本発明の光学補償フィルムのバックコート層形成用塗布組成物に使用される溶剤としては、上記の条件を満たすものを適宜に選定することができる。例えば、メタノール（ＭＡ）、エタノール（ＥＡ）、１－プロパノール（ＮＰＡ）、イソプロパノール（ＩＰＡ）、ブタノール、ペンタノール、ベンジルアルコール、ジアセトンアルコール（ＤＡＡ）等のアルコール系溶剤、アセトン、アセチルアセトン、メチルエチルケトン（ＭＥＫ）、メチルプロピルケトン、メチルイソブチルケトン（ＭＩＢＫ）、シクロヘキサノン、イソホロン等のケトン系溶剤、酢酸メチル、酢酸エチル、酢酸ブチル、酢酸イソブチル、ギ酸アミル、酢酸イソアミル、プロピオン酸ブチル、酪酸イソプロピル、酪酸エチル、酪酸ブチル、乳酸メチル、乳酸エチル、オキシ酢酸メチル、オキシ酢酸エチル、オキシ酢酸ブチル、メトキシ酢酸メチル、メトキシ酢酸エチル、メトキシ酢酸ブチル、エトキシ酢酸メチル、エトキシ酢酸エチル、３－オキシプロピオン酸メチル、３－オキシプロピオン酸エチル、３－メトキシプロピオン酸メチル、３－メトキシプロピオン酸エチル、３－エトキシプロピオン酸メチル、３－エトキシプロピオン酸エチル、２－オキシプロピオン酸メチル、２－オキシプロピオン酸エチル、２－オキシプロピオン酸プロピル、２－メトキシプロピオン酸メチル、２－メトキシプロピオン酸エチル、２－メトキシプロピオン酸プロピル、２－エトキシプロピオン酸メチル、２－エトキシプロピオン酸エチル、２－オキシ－２－メチルプロピオン酸メチル、２－オキシ－２－メチルプロピオン酸エチル、２－メトキシ－２－メチルプロピオン酸メチル、２－エトキシ－２－メチルプロピオン酸エチル、ピルビン酸メチル、ピルビン酸エチル、ピルビン酸プロピル、アセト酢酸メチル、アセト酢酸エチル、２－オキソブタン酸メチル、２－オキソブタン酸エチル等のエステル系溶剤、エチレングリコールモノメチルエーテル（ＭＣＳ）、エチレングリコールモノエチルエーテル（ＥＣＳ）、エチレングリコールイソプロピルエーテル（ＩＰＣ）、エチレングリコールモノブチルエーテル（ＢＣＳ）、エチレングリコールモノエチルエーテルアセテート、エチレングリコールモノブチルエーテルアセテート、プロピレングリコールメチルエーテル（ＰＧＭＥ）、プロピレングリコールエチルエーテル（ＰＥ）、プロピレングリコールメチルエーテルアセテート（ＰＧＭＥＡ）、プロピレングリコールエチルエーテルアセテート（ＰＧＥＥＡ）、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテル、ジエチレングリコールモノメチルエーテルアセテート、ジエチレングリコールモノエチルエーテルアセテート、ジエチレングリコールモノブチルエーテルアセテート、ジエチレングリコールジメチルエーテル、ジエチレングリコールジエチルエーテル、ジエチレングリコールジブチルエーテル、ジプロピレングリコールモノメチルエーテル、ジプロピレングリコールモノエチルエーテル、ジプロピレングリコールモノブチルエーテル等のグリコール誘導体、トルエン、キシレン、メシチレン、ドデシルベンゼン等のベンゼン誘導体、トルエン、キシレン、メシチレン、ドデシルベンゼン等のベンゼン誘導体、ホルムアミド（ＦＡ）、Ｎ－メチルホルムアミド、ジメチルホルムアミド（ＤＭＦ）、ジメチルアセトアミド、ジメチルスルフォキシド（ＤＭＳＯ）、Ｎ－メチル－２－ピロリドン（ＮＭＰ）、γ－ブチロラクトン、エチレングリコール、ジエチレングリコール、テトラヒドロフラン（ＴＨＦ）、クロロホルム、ミネラルスピリッツ、ターピネオール等の中から適宜選択できるが、これらに限定されるものではない。 As the solvent used in the coating composition for forming the backcoat layer of the optical compensation film of the present invention, a solvent satisfying the above conditions can be appropriately selected. For example, alcohol solvents such as methanol (MA), ethanol (EA), 1-propanol (NPA), isopropanol (IPA), butanol, pentanol, benzyl alcohol, diacetone alcohol (DAA), acetone, acetylacetone, methyl ethyl ketone ( MEK), methyl propyl ketone, methyl isobutyl ketone (MIBK), ketone solvents such as cyclohexanone, isophorone, methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, amyl formate, isoamyl acetate, butyl propionate, isopropyl butyrate, ethyl butyrate Butyl butyrate, methyl lactate, ethyl lactate, methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate, methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, Ethyl xyacetate, methyl 3-oxypropionate, ethyl 3-oxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 2-oxypropionate Acid methyl, ethyl 2-oxypropionate, propyl 2-oxypropionate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, methyl 2-ethoxypropionate, 2-ethoxypropionic acid Ethyl, methyl 2-oxy-2-methylpropionate, ethyl 2-oxy-2-methylpropionate, methyl 2-methoxy-2-methylpropionate, ethyl 2-ethoxy-2-methylpropionate, methyl pyruvate, Ethyl pyruvate Ester solvents such as propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl 2-oxobutanoate, ethyl 2-oxobutanoate, ethylene glycol monomethyl ether (MCS), ethylene glycol monoethyl ether (ECS), ethylene glycol isopropyl ether (IPC), ethylene glycol monobutyl ether (BCS), ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol methyl ether (PGME), propylene glycol ethyl ether (PE), propylene glycol methyl ether acetate (PGMEA), Propylene glycol ethyl ether acetate (PGEEA), diethylene glycol monomethyl ether , Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, Glycol derivatives such as dipropylene glycol monobutyl ether, benzene derivatives such as toluene, xylene, mesitylene and dodecylbenzene, benzene derivatives such as toluene, xylene, mesitylene and dodecylbenzene, formamide (FA), N-methylform Mido, dimethylformamide (DMF), dimethylacetamide, dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, ethylene glycol, diethylene glycol, tetrahydrofuran (THF), chloroform, mineral spirits, terpineol Although it can select suitably from etc., it is not limited to these.
　本発明の光学補償フィルムのバックコート層形成用塗布組成物に使用される溶剤とその沸点、およびＳＰ値を、下記の表１に例示した。 The solvents used in the coating composition for forming the back coat layer of the optical compensation film of the present invention, their boiling points, and SP values are illustrated in Table 1 below.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　ここで、上記の条件１および条件２を満足するバックコート層の使用溶剤１と使用溶剤２の組み合わせを例示すると、つぎの通りである。 Here, a combination of the solvent 1 and the solvent 2 in the back coat layer satisfying the above conditions 1 and 2 is exemplified as follows.
　　使用溶剤１　　　　使用溶剤２　混合比
　ＰＧＭＥＡ　　　　：ＩＰＡ　　＝２：８
　ＰＧＭＥＡ　　　　：ＮＰＡ　　＝３：７
　ＰＧＭＥＡ　　　　：メタノール＝３：７
　ＰＧＭＥＡ　　　　：エタノール＝４：６
　メチルエチルケトン：メタノール＝１：９
　メチルエチルケトン：メタノール＝５：５
　酢酸エチル　　　　：メタノール＝３：７
　酢酸エチル　　　　：メタノール＝４：６
　シクロヘキサノン　：ＩＰＡ　　＝２：８
　シクロヘキサノン　：ＮＰＡ　　＝２：８
　シクロヘキサノン　：エタノール＝３：７
　シクロヘキサノン　：メタノール＝２：８
　上記のようなバックコート層形成用塗布組成物を、グラビアコーター、ディップコーター、リバースコーター、ワイヤーバーコーター、ダイコーター、またはスプレー塗布、インクジェット塗布等を用いて透明性フィルム基材の表面にウェット膜厚１～１００μｍで塗布するのが好ましいが、特に５～３０μｍであることが好ましい。 Solvent 1 Solvent 2 Mixing ratio PGMEA: IPA = 2: 8
PGMEA: NPA = 3: 7
PGMEA: Methanol = 3: 7
PGMEA: Ethanol = 4: 6
Methyl ethyl ketone: methanol = 1: 9
Methyl ethyl ketone: methanol = 5: 5
Ethyl acetate: methanol = 3: 7
Ethyl acetate: methanol = 4: 6
Cyclohexanone: IPA = 2: 8
Cyclohexanone: NPA = 2: 8
Cyclohexanone: Ethanol = 3: 7
Cyclohexanone: Methanol = 2: 8
Apply a coating composition for backcoat layer formation as described above onto the surface of a transparent film substrate using a gravure coater, dip coater, reverse coater, wire bar coater, die coater, spray coating, ink jet coating or the like. The coating is preferably performed with a thickness of 1 to 100 μm, particularly preferably 5 to 30 μm.
　バックコート層を塗設する順番は、セルロースエステル系樹脂透明性フィルム基材の活性エネルギー線硬化樹脂層を塗設する前でも後でも構わないが、バックコート層がブロッキング防止層を兼ねる場合は先に塗設することが望ましい。または２回以上に分けてバックコート層を塗布することもできる。
（光学補償フィルムの製造方法）
　本発明による光学補償フィルムは、具体的には、以下のように製造される。 The order of coating the backcoat layer may be before or after coating the active energy ray-curable resin layer of the cellulose ester-based resin transparent film substrate. However, if the backcoat layer also serves as an antiblocking layer, It is desirable to apply to. Alternatively, the backcoat layer can be applied in two or more steps.
(Method for producing optical compensation film)
Specifically, the optical compensation film according to the present invention is manufactured as follows.
　まず、本発明による光学補償フィルムでは、バックコート層がブロッキング防止層を兼ねるために、セルロースエステル系樹脂透明性フィルム基材の片面に、バックコート層を先に塗設し、その後、透明性フィルム基材の他面に、接合用中間層である活性線硬化樹脂層を塗設することが望ましい。 First, in the optical compensation film according to the present invention, since the back coat layer also serves as an anti-blocking layer, the back coat layer is first coated on one side of the cellulose ester resin transparent film substrate, and then the transparent film. It is desirable to coat an active ray curable resin layer, which is a bonding intermediate layer, on the other surface of the substrate.
　バックコート層は、具体的には、微粒子、バインダー、およびセルロースエステル系樹脂透明性フィルム基材を溶解させる溶媒または膨潤させる溶媒、およびフィルム基材を溶解させない溶媒を含むバックコート層形成用塗布組成物を、セルロースエステル系樹脂透明性フィルム基材の表面上に、塗布することによって行なわれる。 Specifically, the backcoat layer is a coating composition for forming a backcoat layer containing fine particles, a binder, a solvent that dissolves the cellulose ester-based resin transparent film substrate or a solvent that swells, and a solvent that does not dissolve the film substrate. This is done by applying the product onto the surface of the cellulose ester resin transparent film substrate.
　上記のようなバックコート層形成用塗布組成物を、グラビアコーター、ディップコーター、リバースコーター、ワイヤーバーコーター、ダイコーター、またはスプレー塗布、インクジェット塗布等を用いて透明性フィルム基材の表面にウェット膜厚１～１００μｍで塗布するのが好ましいが、特に５～３０μｍであることが好ましい。 Apply a coating composition for backcoat layer formation as described above onto the surface of a transparent film substrate using a gravure coater, dip coater, reverse coater, wire bar coater, die coater, spray coating, ink jet coating or the like. The coating is preferably performed with a thickness of 1 to 100 μm, particularly preferably 5 to 30 μm.
　バックコート層を塗設する順番は、セルロースエステル系樹脂透明性フィルム基材の活性エネルギー線硬化樹脂層を塗設する前でも後でも構わないが、バックコート層がブロッキング防止層を兼ねる場合は先に塗設することが望ましい。または２回以上に分けてバックコート層を塗布することもできる。 The order of coating the backcoat layer may be before or after coating the active energy ray-curable resin layer of the cellulose ester-based resin transparent film substrate. However, if the backcoat layer also serves as an antiblocking layer, It is desirable to apply to. Alternatively, the backcoat layer can be applied in two or more steps.
　つぎに、透明性フィルム基材上に、接合用中間層を形成する。具体的には、透明性フィルム基材上に、活性線硬化樹脂を含有する中間層形成用塗布組成物を塗布する。 Next, an intermediate layer for bonding is formed on the transparent film substrate. Specifically, a coating composition for forming an intermediate layer containing an actinic radiation curable resin is applied onto a transparent film substrate.
　塗布方法としては、特に限定されず、公知の塗布方法を用いることができる。具体的には、例えば、グラビアコータ、スピナーコータ、ワイヤーバーコータ、ロールコータ、リバースコータ、押出コータ、エアードクターコータ、ダイコータ、ディップコータ及びインクジェット法等の塗布装置を用いたものが挙げられる。そして、塗布厚みとしては、中間層形成用塗布組成物の固形分濃度等によっても異なるが、具体的には、例えば、形成される接合用中間層の厚みが上記範囲内となるような厚みであることが好ましく、ウェット膜厚で、０．１～４０μｍであることが好ましく、０．５～３０μｍであることがより好ましい。また、ドライ膜厚としては、平均膜厚で０．０１～１μｍであることが好ましく、０．０２～０．７μｍであることがより好ましい。 The coating method is not particularly limited, and a known coating method can be used. Specific examples include a gravure coater, a spinner coater, a wire bar coater, a roll coater, a reverse coater, an extrusion coater, an air doctor coater, a die coater, a dip coater, and an ink jet method. The coating thickness varies depending on the solid content concentration of the coating composition for forming an intermediate layer, but specifically, for example, a thickness such that the thickness of the formed bonding intermediate layer is within the above range. The wet film thickness is preferably 0.1 to 40 μm, and more preferably 0.5 to 30 μm. The dry film thickness is preferably 0.01 to 1 μm in average film thickness, and more preferably 0.02 to 0.7 μm.
　そして、透明性フィルム基材上に塗布された中間層形成用塗布組成物に、活性線を照射して、接合用中間層を形成させる。その際、活性線を照射する前に、透明性フィルム基材上に塗布された中間層形成用塗布組成物を乾燥させておいてもよい。乾燥方法としては、中間層形成用塗布組成物中の有機溶剤を乾燥することができれば、特に限定されない。具体的には、例えば、風乾、加熱除去、及び減圧除去等が挙げられる。これらを単独で行ってもよいし、２種以上を組み合わせて行ってもよい。なお、活性線としては、中間層形成用塗布組成物を硬化させることができれば、特に限定されず、具体的には、例えば、電子線や紫外線等が挙げられる。この中でも、操作性の観点等から、紫外線が好ましい。 Then, the intermediate layer-forming coating composition coated on the transparent film substrate is irradiated with actinic rays to form a bonding intermediate layer. In that case, you may dry the coating composition for intermediate | middle layer formation apply | coated on the transparent film base material before irradiating an active ray. The drying method is not particularly limited as long as the organic solvent in the coating composition for forming an intermediate layer can be dried. Specific examples include air drying, heat removal, and reduced pressure removal. These may be performed alone or in combination of two or more. The actinic radiation is not particularly limited as long as the intermediate layer forming coating composition can be cured, and specific examples thereof include an electron beam and ultraviolet rays. Among these, ultraviolet rays are preferable from the viewpoint of operability.
　また、中間層形成用塗布組成物は、活性線硬化樹脂以外に、通常、有機溶剤が含有されている。 In addition, the coating composition for forming an intermediate layer usually contains an organic solvent in addition to the actinic radiation curable resin.
　有機溶剤としては、活性線硬化樹脂を溶解させることができるものであれば、特に限定されない。具体的には、例えば、トルエン、キシレン等の炭化水素類、メタノール、エタノール、イソプロピルアルコール、ブタノール、シクロヘキサノール等のアルコール類、メチレンクロライド、ジオキソラン、プロピレングリコールモノアルキルエーテル（プロピレングリコールモノメチルエーテル等）等のグリコールエーテル類、プロピレングリコールモノメチルエーテル酢酸エステル等のグリコールエーテル類のカルボン酸エステル、酢酸エチル、酢酸メチル、乳酸メチル等のエステル類、アセトン、メチルエチルケトン、メチルイソブチルケトン等のケトン類、及びジアセトンアルコール等のケトンアルコール類等が挙げられる。この中でも、アルキル基の炭素数が１～４のプロピレングリコールモノアルキルエーテルやアルキル基の炭素数が１～４のプロピレングリコールモノアルキルエーテル酢酸エステル等が好ましい。また、これらは、単独で用いてもよいし、２種以上を組み合わせて用いてもよい。また、中間層形成用塗布組成物中の有機溶剤濃度は、組成等によって異なるが、例えば、５～８０質量％程度であることが好ましい。 The organic solvent is not particularly limited as long as it can dissolve the actinic radiation curable resin. Specifically, for example, hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, isopropyl alcohol, butanol and cyclohexanol, methylene chloride, dioxolane, propylene glycol monoalkyl ether (propylene glycol monomethyl ether, etc.), etc. Glycol ethers, carboxylic acid esters of glycol ethers such as propylene glycol monomethyl ether acetate, esters such as ethyl acetate, methyl acetate and methyl lactate, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and diacetone alcohol Ketone alcohols and the like. Of these, propylene glycol monoalkyl ethers having 1 to 4 carbon atoms in the alkyl group and propylene glycol monoalkyl ether acetates having 1 to 4 carbon atoms in the alkyl group are preferable. Moreover, these may be used independently and may be used in combination of 2 or more type. The concentration of the organic solvent in the coating composition for forming an intermediate layer varies depending on the composition and the like, but is preferably about 5 to 80% by mass, for example.
　また、中間層形成用塗布組成物は、活性線硬化樹脂以外に、例えば、セルロースエステル系樹脂、後述する光重合開始剤等を含有していてもよい。より具体的には、例えば、中間層形成用塗布組成物には、光重合開始剤を含有してもよい。電子線を照射することによって重合させる場合には、光重合開始剤が不要であるが、一般的に用いられている重合、例えば、紫外線（ＵＶ）照射による重合の場合には、重合を促進させるために光重合開始剤を含有させることが好ましい。そうすることによって、重合温度を低くすることができる。 Moreover, the coating composition for forming the intermediate layer may contain, for example, a cellulose ester resin, a photopolymerization initiator described later, and the like in addition to the actinic radiation curable resin. More specifically, for example, the intermediate layer forming coating composition may contain a photopolymerization initiator. In the case of polymerization by irradiation with an electron beam, a photopolymerization initiator is not required. However, in the case of polymerization generally used, for example, polymerization by ultraviolet (UV) irradiation, the polymerization is promoted. Therefore, it is preferable to contain a photopolymerization initiator. By doing so, the polymerization temperature can be lowered.
　光重合開始剤としては、活性線硬化樹脂の硬化反応の開始に寄与できればよく、具体的には、例えば、α－ヒドロキシケトン、アセトフェノン、ベンゾフェノン、ヒドロキシベンゾフェノン、ミヒラーズケトン、α－アミロキシムエステル、チオキサントン等及びこれらの誘導体等が挙げられる。この中でも、α－ヒドロキシケトン及びこの誘導体が好ましい。また、これらは、単独で用いてもよいし、２種以上を組み合わせて用いてもよい。また、光重合開始剤の含有量は、例えば、活性線硬化樹脂１００質量部に対して０．１～１質量部程度であることが好ましい。 As the photopolymerization initiator, it is only necessary to contribute to the initiation of the curing reaction of the actinic radiation curable resin. Specifically, for example, α-hydroxyketone, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone And derivatives thereof. Of these, α-hydroxyketone and derivatives thereof are preferred. Moreover, these may be used independently and may be used in combination of 2 or more type. The content of the photopolymerization initiator is preferably about 0.1 to 1 part by mass with respect to 100 parts by mass of the actinic radiation curable resin, for example.
　紫外線を照射する光源としては、紫外線を発生する光源であれば、限定なく使用できる。具体的には、例えば、低圧水銀灯、中圧水銀灯、高圧水銀灯、超高圧水銀灯、カーボンアーク灯、メタルハライドランプ、及びキセノンランプ等が挙げられる。 As the light source for irradiating ultraviolet rays, any light source that generates ultraviolet rays can be used without limitation. Specific examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, carbon arc lamps, metal halide lamps, and xenon lamps.
　紫外線の照射条件は、光源や中間層形成用塗布組成物等によって異なるが、活性線の照射量は、通常５～５００ｍＪ／ｃｍ２であり、好ましくは、５～１５０ｍＪ／ｃｍ２である。 The irradiation conditions of ultraviolet light varies by the light source and the intermediate layer coating composition, etc., the dose of active ray is usually 5 ~ 500mJ / cm 2, preferably from 5 ~ 150mJ / cm 2.
　また、活性線を照射する際には、フィルムの搬送方向に張力を付与しながら行うことが好ましく、さらに好ましくは幅方向にも張力を付与しながら行うことである。付与する張力は３０～３００Ｎ／ｍであることが好ましい。 Further, when irradiating active rays, it is preferably performed while applying tension in the film transport direction, more preferably while applying tension in the width direction. The tension to be applied is preferably 30 to 300 N / m.
　張力を付与する方法は、特に限定されず、バックロール上で搬送方向に張力を付与してもよく、テンターにて幅方向、または２軸方向に張力を付与してもよい。これによってさらに平面性優れたフィルムを得ることができる。 The method of applying tension is not particularly limited, and tension may be applied in the transport direction on the back roll, or tension may be applied in the width direction or biaxial direction by a tenter. This makes it possible to obtain a film having further excellent flatness.
　つぎに、接合用中間層上に光学異方性層を形成する。具体的には、接合用中間層上に、液晶化合物を含有する光学異方性層形成用塗布組成物を塗布する。 Next, an optically anisotropic layer is formed on the bonding intermediate layer. Specifically, a coating composition for forming an optically anisotropic layer containing a liquid crystal compound is applied onto the bonding intermediate layer.
　塗布方法としては、特に限定されず、公知の塗布方法を用いることができる。具体的には、例えば、スピンコート法、ロールコート法、プリント法、浸漬引き上げ法、ダイコート法、キャスティング法、バーコート法、ブレードコート法、スプレーコート法、グラビアコート法、リバースコート法、及び押出コート法等が挙げられる。そして、塗布厚みとしては、光学異方性層形成用塗布組成物の固形分濃度等によっても異なるが、具体的には、例えば、形成される光学異方性層の厚みが上記範囲内となるような厚みであることが好ましく、ドライ膜厚としては、平均膜厚で０．１～１０μｍであることが好ましく、０．２～５μｍであることがより好ましい。 The coating method is not particularly limited, and a known coating method can be used. Specifically, for example, spin coating method, roll coating method, printing method, dip pulling method, die coating method, casting method, bar coating method, blade coating method, spray coating method, gravure coating method, reverse coating method, and extrusion Examples thereof include a coating method. The coating thickness varies depending on the solid content concentration of the coating composition for forming an optically anisotropic layer. Specifically, for example, the thickness of the formed optically anisotropic layer is within the above range. The dry film thickness is preferably 0.1 to 10 μm and more preferably 0.2 to 5 μm as an average film thickness.
　そして、接合用中間層上に塗布された光学異方性層形成用塗布組成物を乾燥させる。乾燥方法としては、光学異方性層形成用塗布組成物中の有機溶剤を乾燥することができれば、特に限定されない。具体的には、例えば、風乾、加熱除去、及び減圧除去等が挙げられる。これらを単独で行ってもよいし、２種以上を組み合わせて行ってもよい。 Then, the coating composition for forming an optically anisotropic layer applied on the bonding intermediate layer is dried. The drying method is not particularly limited as long as the organic solvent in the coating composition for forming an optically anisotropic layer can be dried. Specific examples include air drying, heat removal, and reduced pressure removal. These may be performed alone or in combination of two or more.
　そして、接合用中間層上に塗布され、乾燥された光学異方性層形成用塗布組成物を、液晶化合物の液晶転移温度以上に加熱することによって、液晶化合物を配向させる。その配向時間としては、例えば、１～１０分間程度かかる。なお、ここで、液晶転移温度とは、固体－液晶相転移温度を指す。そして、光学異方性層形成用塗布組成物を塗布した後の液晶転移温度以上までの加熱は、液晶－等方性液体相転移温度以下までであることが好ましい。また、加熱速度は、１０～１５０℃／秒であることが好ましい。 Then, the liquid crystal compound is aligned by heating the coating composition for forming an optically anisotropic layer applied on the bonding intermediate layer and dried to a temperature higher than the liquid crystal transition temperature of the liquid crystal compound. The alignment time takes about 1 to 10 minutes, for example. Here, the liquid crystal transition temperature refers to a solid-liquid crystal phase transition temperature. The heating up to the liquid crystal transition temperature or higher after coating the coating composition for forming an optically anisotropic layer is preferably up to the liquid crystal-isotropic liquid phase transition temperature or lower. The heating rate is preferably 10 to 150 ° C./second.
　その後、光学異方性層形成用塗布組成物を、液晶化合物の液晶転移温度以下に冷却し、その配向を固定し、その状態で、光学異方性層形成用塗布組成物に活性線を照射する。そうすることによって、その配向性がより固定され、そして、液晶化合物が垂直配向した光学異方性層が形成される。すなわち、この工程は、液晶化合物が、活性線の照射により重合可能な官能基を有する重合性液晶化合物である場合、光学異方性層形成用塗布組成物を冷却した後、光学異方性層形成用塗布組成物に活性線を照射して、光学異方性層形成用塗布組成物を硬化させる工程である。そうすることによって、光学異方性層を容易に形成できる。 Thereafter, the coating composition for forming an optically anisotropic layer is cooled below the liquid crystal transition temperature of the liquid crystal compound, the orientation is fixed, and in this state, the coating composition for forming the optically anisotropic layer is irradiated with active rays. To do. By doing so, the orientation is more fixed, and an optically anisotropic layer in which the liquid crystal compound is vertically aligned is formed. That is, in this step, when the liquid crystal compound is a polymerizable liquid crystal compound having a functional group that can be polymerized by irradiation with active rays, the coating composition for forming the optical anisotropic layer is cooled, and then the optical anisotropic layer is formed. This is a step of irradiating the forming coating composition with active rays to cure the optically anisotropic layer forming coating composition. By doing so, an optically anisotropic layer can be formed easily.
　また、光学異方性層形成用塗布組成物は、液晶化合物以外に、通常、後述する有機溶剤が含有されている。 In addition, the coating composition for forming an optically anisotropic layer usually contains an organic solvent described later in addition to the liquid crystal compound.
　有機溶剤としては、液晶化合物を溶解させることができるものであれば、特に限定されない。また、有機溶剤としては、透明性フィルム基材や接合用中間層の性状を低下させない溶媒であることが好ましい。具体的には、例えば、ベンゼン、トルエン等の炭化水素類、メトキシベンゼン、ジエチレングリコールジメチルエーテル等のエーテル類、アセトン、メチルエチルケトン、メチルイソブチルケトン、シクロヘキサノン等のケトン類、酢酸エチル、エチレングリコールモノメチルエーテルアセテート、プロピレングリコールモノメチルエーテルアセテート、γ－ブチロラクトン等のエステル類、２－ピロリドン、Ｎ－メチル－２－ピロリドン、ジメチルホルムアミド等のアミド系溶媒、ジクロロメタン、四塩化炭素、ジクロロエタン、テトラクロロエタン、トリトリクロロエチレン、テトラクロロエチレン等のハロゲン系溶媒、ｔ－ブチルアルコール、ジアセトンアルコール、グリセリン、モノアセチン、エチレングリコール、トリエチレングリコール、エチレングリコールモノメチルエーテル、エチルセルソルブ等のアルコール類、フェノール、パラクロロフェノール等のフェノール類等が挙げられる。これらは、単独で用いてもよいし、２種以上を組み合わせて用いてもよい。 The organic solvent is not particularly limited as long as it can dissolve the liquid crystal compound. Moreover, as an organic solvent, it is preferable that it is a solvent which does not reduce the property of a transparent film base material or the intermediate | middle layer for joining. Specifically, for example, hydrocarbons such as benzene and toluene, ethers such as methoxybenzene and diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate, ethylene glycol monomethyl ether acetate, propylene Esters such as glycol monomethyl ether acetate, γ-butyrolactone, amide solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, tritrichloroethylene, tetrachloroethylene, etc. Halogen solvent, t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol Call, ethylene glycol monomethyl ether, alcohols such as ethyl cellosolve, phenol, phenols such as p-chlorophenol, and the like. These may be used alone or in combination of two or more.
　また、有機溶媒の中でも、単独用いる溶媒として好ましいものは、炭化水素系溶媒、及びエチレングリコールモノメチルエーテルアセテートやプロピレングリコールモノメチルエーテルアセテート等のグリコールモノエーテルアセテート系溶媒であり、組み合わせて用いる溶媒として好ましいのは、エーテル類又はケトン類と、グリコール類とを組み合わせて用いる混合溶媒である。 Further, among organic solvents, preferred as a solvent to be used alone are hydrocarbon solvents and glycol monoether acetate solvents such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, and are preferred as solvents to be used in combination. Is a mixed solvent using ethers or ketones in combination with glycols.
　また、光学異方性層形成用塗布組成物の固形分濃度としては、液晶化合物の溶解性や光学異方性層の膜厚等によって異なるが、例えば、０．１～６０質量％程度であることが好ましく、３～４０質量％程度であることがより好ましい。 Further, the solid content concentration of the coating composition for forming an optically anisotropic layer varies depending on the solubility of the liquid crystal compound, the film thickness of the optically anisotropic layer, etc., but is, for example, about 0.1 to 60% by mass. It is preferably about 3 to 40% by mass.
　また、光学異方性層形成用塗布組成物には、液晶化合物以外に、例えば、液晶化合物として、重合性官能基を有する重合性液晶等を用いる場合、後述する光重合開始剤等を含有していてもよい。電子線を照射することによって重合させる場合には、光重合開始剤が不要であるが、一般的に用いられている重合、例えば、紫外線（ＵＶ）照射による重合の場合には、重合を促進させるために光重合開始剤を含有させることが好ましい。そうすることによって、重合温度を低くすることができ、固定化が好適に行うことができる。 In addition to the liquid crystal compound, for example, when a polymerizable liquid crystal having a polymerizable functional group is used as the liquid crystal compound, the coating composition for forming an optically anisotropic layer contains a photopolymerization initiator described later. It may be. In the case of polymerization by irradiation with an electron beam, a photopolymerization initiator is not required. However, in the case of polymerization generally used, for example, polymerization by ultraviolet (UV) irradiation, the polymerization is promoted. Therefore, it is preferable to contain a photopolymerization initiator. By doing so, the polymerization temperature can be lowered, and immobilization can be suitably performed.
　光重合開始剤としては、特に限定されないが、具体的には、例えば、ベンジル（ビベンゾイル）、ベンゾインイソブチルエーテル、ベンゾインイソプロピルエーテル、ベンゾフェノン、ベンゾイル安息香酸、ベンゾイル安息香酸メチル、４－ベンゾイル－４′－メチルジフェニルサルファイド、ベンジルメチルケタール、ジメチルアミノメチルベンゾエート、２－ｎ－ブトキシエチル－４－ジメチルアミノベンゾエート、ｐ－ジメチルアミノ安息香酸イソアミル、３，３′－ジメチル－４－メトキシベンゾフェノン、メチロベンゾイルフォーメート、２－メチル－１－（４－（メチルチオ）フェニル）－２－モルフォリノプロパン－１－オン、２－ベンジル－２－ジメチルアミノ－１－（４－モルフォリノフェニル）－ブタン－１－オン、１－（４－ドデシルフェニル）－２－ヒドロキシ－２－メチルプロパン－１－オン、１－ヒドロキシシクロヘキシルフェニルケトン、２－ヒドロキシ－２－メチル－１－フェニルプロパン－１－オン、１－（４－イソプロピルフェニル）－２－ヒドロキシ－２－メチルプロパン－１－オン、２－クロロチオキサントン、２，４－ジエチルチオキサントン、２，４－ジイソプロピルチオキサントン、２，４－ジメチルチオキサントン、イソプロピルチオキサントン、及び１－クロロ－４－プロポキシチオキサントン等が挙げられる。また、これらは、単独で用いてもよいし、２種以上を組み合わせて用いてもよい。 The photopolymerization initiator is not particularly limited. Specifically, for example, benzyl (bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, benzoyl methyl benzoate, 4-benzoyl-4'- Methyl diphenyl sulfide, benzyl methyl ketal, dimethylaminomethyl benzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3'-dimethyl-4-methoxybenzophenone, methylobenzoylpho Mate, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1- on, -(4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4- Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, and 1-chloro -4-propoxythioxanthone and the like. Moreover, these may be used independently and may be used in combination of 2 or more type.
　光重合開始剤の含有量としては、０．０１～２０質量％であることが好ましく、０．１～１０質量％であることがより好ましく、０．５～５質量％であることがさらに好ましい。光重合開始剤の含有量が少なすぎると、光重合開始剤の効果が発揮できない傾向にあり、また、多すぎると、液晶化合物の重合性が低下して、分子量が低くなり、よって、耐擦傷性等が低下する傾向がある。 The content of the photopolymerization initiator is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, and further preferably 0.5 to 5% by mass. . If the content of the photopolymerization initiator is too small, the effect of the photopolymerization initiator tends not to be exhibited. If the content is too large, the polymerizability of the liquid crystal compound is lowered and the molecular weight is lowered, so that the scratch resistance is reduced. There is a tendency for the sex etc. to decrease.
　また、光学異方性層形成用塗布組成物には、本発明の目的が損なわれない範囲で、増感剤を含有させてもよい。増感剤としては、特に限定されないが、具体的には、例えば、日本化薬株式会社製のカヤキュアＤＥＴＸ等が挙げられる。 Moreover, the coating composition for forming an optically anisotropic layer may contain a sensitizer as long as the object of the present invention is not impaired. Although it does not specifically limit as a sensitizer, Specifically, Nippon Kayaku Co., Ltd. Kayacure DETX etc. are mentioned, for example.
　また、光学異方性層形成用塗布組成物には、上記各組成以外にも、本発明の目的を損なわない範囲内で、下記添加剤を含有させてもよい。 In addition to the above compositions, the coating composition for forming an optically anisotropic layer may contain the following additives as long as the object of the present invention is not impaired.
　添加剤としては、まず、例えば、多価アルコールと１塩基酸又は多塩基酸を縮合して得られるポリエステルプレポリマーに、（メタ）アクリル酸を反応させて得られるポリエステル（メタ）アクリレート；ポリオール基と２個のイソシアネート基を持つ化合物を互いに反応させた後、その反応生成物に（メタ）アクリル酸を反応させて得られるポリウレタン（メタ）アクリレート；ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ノボラック型エポキシ樹脂、ポリカルボン酸ポリグリシジルエステル、ポリオールポリグリシジルエーテル、脂肪族もしくは脂環式エポキシ樹脂、アミンエポキシ樹脂、トリフェノールメタン型エポキシ樹脂、ジヒドロキシベンゼン型エポキシ樹脂等のエポキシ樹脂と、（メタ）アクリル酸を反応させて得られるエポキシ（メタ）アクリレート等の光重合性化合物、及びアクリル基又はメタクリル基を有する光重合性の液晶性化合物、特開２００７－４５９９３号公報に記載のオニウム塩、フッ化アクリレートポリマー等が挙げられる。添加剤の添加により、光学異方性層形成用塗布組成物の硬化性が向上し、得られる光学異方性層の機械強度が増大し、またその安定性が改善される。 As an additive, for example, a polyester (meth) acrylate obtained by reacting (meth) acrylic acid with a polyester prepolymer obtained by condensing a polyhydric alcohol and a monobasic acid or polybasic acid; for example, a polyol group And a compound having two isocyanate groups are reacted with each other, and then a polyurethane (meth) acrylate obtained by reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, Epoxy resins such as novolac type epoxy resin, polycarboxylic acid polyglycidyl ester, polyol polyglycidyl ether, aliphatic or cycloaliphatic epoxy resin, amine epoxy resin, triphenolmethane type epoxy resin, dihydroxybenzene type epoxy resin, )acrylic A photopolymerizable compound such as an epoxy (meth) acrylate obtained by reacting with a photopolymerizable liquid crystal compound having an acryl group or a methacryl group, an onium salt and a fluorinated acrylate described in JP-A-2007-45993 Examples thereof include polymers. Addition of the additive improves the curability of the coating composition for forming an optically anisotropic layer, increases the mechanical strength of the resulting optically anisotropic layer, and improves its stability.
　また、添加剤の含有量は、本発明の目的が損なわれない範囲で選択され、一般的には、光学異方性層形成用塗布組成物の４０質量％以下であることが好ましく、２０質量％以下であることが好ましい。 The content of the additive is selected within a range that does not impair the object of the present invention, and is generally preferably 40% by mass or less of the coating composition for forming an optically anisotropic layer, and 20% by mass. % Or less is preferable.
　また、溶媒を含有する光学異方性層形成用塗布組成物には、塗工を容易にするために界面活性剤等を含有させてもよい。界面活性剤としては、具体的には、例えば、イミダゾリン、第四級アンモニウム塩、アルキルアミンオキサイド、ポリアミン誘導体等の陽イオン系界面活性剤；ポリオキシエチレン－ポリオキシプロピレン縮合物、第一級あるいは第二級アルコールエトキシレート、アルキルフェノールエトキシレート、ポリエチレングリコールおよびそのエステル、ラウリル硫酸ナトリウム、ラウリル硫酸アンモニウム、ラウリル硫酸アミン類、アルキル置換芳香族スルホン酸塩、アルキルリン酸塩、脂肪族あるいは芳香族スルホン酸ホルマリン縮合物等の陰イオン系界面活性剤；ラウリルアミドプロピルベタイン、ラウリルアミノ酢酸ベタイン等の両性系界面活性剤；ポリエチレングリコール脂肪酸エステル類、ポリオキシエチレンアルキルアミン等の非イオン系界面活性剤；パーフルオロアルキルスルホン酸塩、パーフルオロアルキルカルボン酸塩、パーフルオロアルキルエチレンオキシド付加物、パーフルオロアルキルトリメチルアンモニウム塩、パーフルオロアルキル基・親水性基含有オリゴマー、パーフルオロアルキル・親油基含有オリゴマーパーフルオロアルキル基含有ウレタン等のフッ素系界面活性剤などが挙げられる。 In addition, the coating composition for forming an optically anisotropic layer containing a solvent may contain a surfactant or the like in order to facilitate coating. Specific examples of the surfactant include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides and polyamine derivatives; polyoxyethylene-polyoxypropylene condensates, primary or Secondary alcohol ethoxylate, alkylphenol ethoxylate, polyethylene glycol and its esters, sodium lauryl sulfate, ammonium lauryl sulfate, lauryl sulfate amines, alkyl-substituted aromatic sulfonates, alkyl phosphates, aliphatic or aromatic sulfonate formalin Anionic surfactants such as condensates; amphoteric surfactants such as laurylamidopropylbetaine and laurylaminoacetic acid betaine; non-polyethylene glycol fatty acid esters, polyoxyethylene alkylamines and the like ON-based surfactant: perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl trimethyl ammonium salt, perfluoroalkyl group / hydrophilic group-containing oligomer, perfluoroalkyl / parent Fluorosurfactants such as oil group-containing oligomer perfluoroalkyl group-containing urethanes.
　界面活性剤の含有量としては、界面活性剤の種類、液晶材料の種類、溶媒の種類、さらには溶液を塗工する配向膜の種類等にもよっても異なるが、通常は、液晶化合物に対して、１０ｐｐｍ～１０質量％であることが好ましく、１００ｐｐｍ～５質量％であることが好ましく、０．１～１質量％であることが好ましい。 The surfactant content varies depending on the type of surfactant, the type of liquid crystal material, the type of solvent, and the type of alignment film on which the solution is applied. Thus, it is preferably 10 ppm to 10% by mass, preferably 100 ppm to 5% by mass, and preferably 0.1 to 1% by mass.
　活性線としては、中間層形成用塗布組成物を硬化させることができれば、特に限定されず、具体的には、例えば、電子線や紫外線等が挙げられる。この中でも、操作性の観点等から、紫外線や可視光が好ましく、紫外線がより好ましい。紫外線での硬化は、技術が確立していることや、可視光で硬化する場合より、利用しやすい点から好ましい。波長としては、具体的には、例えば、１５０～５００ｎｍであることが好ましく、２５０～４５０ｎｍであることがより好ましく、３００～４００ｎｍであることが好ましい。 The active ray is not particularly limited as long as the coating composition for forming an intermediate layer can be cured, and specific examples thereof include an electron beam and ultraviolet rays. Among these, from the viewpoint of operability, ultraviolet rays and visible light are preferable, and ultraviolet rays are more preferable. Curing with ultraviolet rays is preferable from the viewpoint that the technology is established and it is easier to use than curing with visible light. Specifically, the wavelength is preferably, for example, 150 to 500 nm, more preferably 250 to 450 nm, and preferably 300 to 400 nm.
　紫外線を照射する光源としては、紫外線を発生する光源であれば、限定なく使用できる。具体的には、例えば、殺菌ランプ、蛍光ケミカルランプ、ブラックライト等の低圧水銀ランプ、高圧水銀ランプ、メタルハライドランプ等の高圧放電ランプ、超高圧水銀ランプ、キセノンランプ、水銀キセノンランプ等のショートアーク放電ランプ等が挙げられる。この中でも、メタルハライドランプ、キセノンランプ、高圧水銀ランプ灯等の使用が推奨される。 As the light source for irradiating ultraviolet rays, any light source that generates ultraviolet rays can be used without limitation. Specifically, for example, low-pressure mercury lamps such as sterilization lamps, fluorescent chemical lamps, and black lights, high-pressure discharge lamps such as high-pressure mercury lamps and metal halide lamps, short arc discharges such as ultra-high-pressure mercury lamps, xenon lamps, and mercury xenon lamps A lamp etc. are mentioned. Among these, use of a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, etc. is recommended.
　紫外線の照射条件は、光源や光学異方性層形成用塗布組成物等によって異なるが、活性線の照射量は、通常５～５００ｍＪ／ｃｍ２であり、好ましくは、５～１５０ｍＪ／ｃｍ２である。 The irradiation conditions of ultraviolet rays vary depending on the light source, the coating composition for forming an optically anisotropic layer, etc., but the irradiation amount of active rays is usually 5 to 500 mJ / cm 2 , preferably 5 to 150 mJ / cm 2 . is there.
　また、上述したように、透明性フィルム基材が、長尺状であり、第１塗布工程、中間層形成工程、第２塗布工程、配向工程、及び固定化工程の各工程が、透明性フィルム基材を長手方向に搬送しながら行われている場合、透明性フィルム基材の幅が、１０００ｍｍ以上であって、透明性フィルム基材の搬送速度が、４０ｍ／分以上であることが好ましい。ここでの透明性フィルム基材の搬送速度は、中間層形成用塗布組成物や光学異方性層形成用塗布組成物の塗布速度に相当する。 In addition, as described above, the transparent film substrate has a long shape, and the first coating step, the intermediate layer forming step, the second coating step, the orientation step, and the immobilization step are each performed as a transparent film. When it is performed while conveying the substrate in the longitudinal direction, the width of the transparent film substrate is preferably 1000 mm or more, and the conveyance speed of the transparent film substrate is preferably 40 m / min or more. The conveyance speed of the transparent film base material here corresponds to the coating speed of the coating composition for forming an intermediate layer and the coating composition for forming an optically anisotropic layer.
　このような広幅の光学補償フィルムを、上記のような高速で透明性フィルム基材を搬送して製造しようとすると、一般的に、中間層形成用塗布組成物や光学異方性層形成用塗布組成物の塗布むら等が発生して、形成される接合用中間層や光学異方性層に欠陥が発生しやすいが、上記の製造方法によれば、接合用中間層及び光学異方性層において欠陥の発生を抑制でき、接合用中間層と光学異方性層との密着性が充分に高く、さらに、光学異方性層の液晶化合物の配向性が充分に高い光学補償フィルムを容易に製造することができる。 When trying to manufacture such a wide optical compensation film by transporting the transparent film substrate at a high speed as described above, generally, a coating composition for forming an intermediate layer or a coating for forming an optically anisotropic layer is used. The coating unevenness of the composition occurs, and defects are likely to occur in the formed bonding intermediate layer and optically anisotropic layer. According to the above production method, the bonding intermediate layer and the optically anisotropic layer are formed. Generation of defects in the optical compensation film, the adhesion between the bonding intermediate layer and the optically anisotropic layer is sufficiently high, and the orientation of the liquid crystal compound in the optically anisotropic layer is sufficiently high. Can be manufactured.
　本発明による光学補償フィルムの厚みは、２０μｍ以上であることが好ましく、２０～８０μｍであることがより好ましい。ここでの厚みとは、平均膜厚のことであり、株式会社ミツトヨ製の接触式膜厚計により、フィルムの幅方向に２０～２００箇所、膜厚を測定し、その測定値の平均値を膜厚として示す。また、透明性フィルム基材の幅、物性、及び形状等は、特に限定なく、製造する光学補償フィルムの目的に合わせて、適宜選択することができ、特に限定されないが、光学補償フィルムの幅は、大型の液晶表示装置への使用、偏光板加工時のフィルムの使用効率、生産効率の点から、１０００ｍｍ以上であることが好ましく、１０００～４０００ｍｍであることがより好ましい。
（偏光板）
　偏光板は、偏光素子と、偏光素子の表面上に配置された透明保護フィルムとを備え、透明保護フィルムが、光学補償フィルムである。偏光素子とは、入射光の偏光を直線偏光に変えて射出する光学素子である。 The thickness of the optical compensation film according to the present invention is preferably 20 μm or more, and more preferably 20 to 80 μm. The thickness here means the average film thickness. The thickness is measured at 20 to 200 locations in the width direction of the film with a contact-type film thickness meter manufactured by Mitutoyo Corporation, and the average value of the measured values is calculated. Shown as film thickness. Further, the width, physical properties, and shape of the transparent film substrate are not particularly limited and can be appropriately selected according to the purpose of the optical compensation film to be manufactured. From the viewpoint of use in a large-sized liquid crystal display device, use efficiency of a film during polarizing plate processing, and production efficiency, it is preferably 1000 mm or more, and more preferably 1000 to 4000 mm.
(Polarizer)
The polarizing plate includes a polarizing element and a transparent protective film disposed on the surface of the polarizing element, and the transparent protective film is an optical compensation film. The polarizing element is an optical element that emits light by changing the polarization of incident light to linearly polarized light.
　偏光板としては、例えば、ポリビニルアルコール系フィルムをヨウ素溶液中に浸漬して延伸することによって作製される偏光素子の少なくとも一方の表面に、完全鹸化型ポリビニルアルコール水溶液を用いて、光学補償フィルムを貼り合わせたものが好ましい。また、偏光素子のもう一方の表面にも、光学補償フィルムを積層させてもよいし、別の偏光板用の透明保護フィルムを積層させてもよい。この偏光板用の透明保護フィルムとしては、例えば、市販のセルロースエステルフィルムとして、コニカミノルタオプト株式会社製の、ＫＣ８ＵＸ２Ｍ、ＫＣ４ＵＸ、ＫＣ５ＵＸ、ＫＣ４ＵＹ、ＫＣ８ＵＹ、ＫＣ１２ＵＲ、ＫＣ８ＵＹ－ＨＡ、ＫＣ８ＵＸ－ＲＨＡ、ＫＣ４ＦＲ－１、ＫＣ４ＨＲ－１、ＫＣ８ＵＣＲ－３、ＫＣ８ＵＣＲ－４、ＫＣ８ＵＣＲ－５等が好ましく用いられる。あるいは、セルロースエステルフィルム以外の環状オレフィン樹脂、アクリル樹脂、ポリエステル、ポリカーボネート等の樹脂フィルムを用いてもよい。この場合は、ケン化適性が低いため、適当な接着層を介して偏光板に接着加工することが好ましい。 As the polarizing plate, for example, an optical compensation film is attached to at least one surface of a polarizing element prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution, using a completely saponified polyvinyl alcohol aqueous solution. Those combined are preferred. Further, an optical compensation film may be laminated on the other surface of the polarizing element, or a transparent protective film for another polarizing plate may be laminated. As the transparent protective film for the polarizing plate, for example, as a commercially available cellulose ester film, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UY-HA, KC8UX-RHA, KC4FR- manufactured by Konica Minolta Opto Co., Ltd. 1, KC4HR-1, KC8UCR-3, KC8UCR-4, KC8UCR-5 and the like are preferably used. Or you may use resin films, such as cyclic olefin resin other than a cellulose-ester film, an acrylic resin, polyester, a polycarbonate. In this case, since the saponification suitability is low, it is preferable to perform an adhesive process on the polarizing plate through an appropriate adhesive layer.
　偏光板は、上述のように、偏光素子の少なくとも一方の表面側に積層する保護フィルムとして、光学補償フィルムを使用したものである。その際、光学補償フィルムが位相差フィルム等の光学補償フィルムとして働く場合、光学補償フィルムの遅相軸が偏光素子の吸収軸に実質的に平行または直交するように配置されていることが好ましい。 As described above, the polarizing plate uses an optical compensation film as a protective film laminated on at least one surface side of the polarizing element. At that time, when the optical compensation film works as an optical compensation film such as a retardation film, it is preferable that the slow axis of the optical compensation film is arranged so as to be substantially parallel or perpendicular to the absorption axis of the polarizing element.
　また、偏光素子の具体例としては、例えば、ポリビニルアルコール系偏光フィルムが挙げられる。ポリビニルアルコール系偏光フィルムは、ポリビニルアルコール系フィルムにヨウ素を染色させたものと二色性染料を染色させたものとがある。ポリビニルアルコール系フィルムとしては、エチレンで変性された変性ポリビニルアルコール系フィルムが好ましく用いられる。 Further, specific examples of the polarizing element include, for example, a polyvinyl alcohol polarizing film. Polyvinyl alcohol polarizing films include those obtained by dyeing iodine on polyvinyl alcohol films and those obtained by dyeing dichroic dyes. As the polyvinyl alcohol film, a modified polyvinyl alcohol film modified with ethylene is preferably used.
　偏光素子は、例えば、以下のようにして得られる。まず、ポリビニルアルコール水溶液を用いて製膜する。得られたポリビニルアルコール系フィルムを一軸延伸させた後染色するか、染色した後一軸延伸する。そして、好ましくはホウ素化合物で耐久性処理を施す。 The polarizing element is obtained as follows, for example. First, a film is formed using a polyvinyl alcohol aqueous solution. The obtained polyvinyl alcohol film is uniaxially stretched and then dyed or dyed and then uniaxially stretched. And preferably, a durability treatment is performed with a boron compound.
　偏光素子の膜厚は、５～４０μｍであることが好ましく、５～３０μｍであることがより好ましく、５～２０μｍであることがより好ましい。 The film thickness of the polarizing element is preferably 5 to 40 μm, more preferably 5 to 30 μm, and even more preferably 5 to 20 μm.
　該偏光素子の表面上に、セルロースエステルを含むセルロースエステル系光学補償フィルムを張り合わせる場合、完全鹸化ポリビニルアルコール等を主成分とする水系の接着剤によって貼り合わせることが好ましい。また、セルロースエステル系光学補償フィルム以外の光学補償フィルムの場合は、適当な粘着層を介して偏光板に接着加工することが好ましい。 When a cellulose ester-based optical compensation film containing a cellulose ester is laminated on the surface of the polarizing element, it is preferably bonded with a water-based adhesive mainly composed of completely saponified polyvinyl alcohol. Further, in the case of an optical compensation film other than the cellulose ester-based optical compensation film, it is preferable to perform an adhesive process on the polarizing plate through an appropriate adhesive layer.
　上述のような偏光板は、透明保護フィルムとして、上記実施形態による光学補償フィルムを用いることによって、光学補償フィルムが光学補償性能等に優れているので、光学補償性能等に優れた偏光板が得られる。 The polarizing plate as described above uses the optical compensation film according to the above embodiment as a transparent protective film, so that the optical compensation film is excellent in optical compensation performance and the like, and thus a polarizing plate excellent in optical compensation performance and the like is obtained. It is done.
　このような構成によれば、偏光板の透明保護フィルムとして、光学補償性能に優れた光学補償フィルムが適用されているので、例えば、液晶表示装置に適用した際に、視野角の拡大やコントラストの向上等の、液晶表示装置の高画質化を実現できる偏光板が得られる。
（液晶表示装置）
　液晶表示装置は、液晶セルと、液晶セルを挟むように配置された２枚の偏光板とを備える。なお、液晶セルとは、一対の電極間に液晶物質が充填されたものであり、この電極に電圧を印加することで、液晶の配向状態が変化され、透過光量が制御される。このような液晶表示装置は、光学補償性能等に優れた偏光板が用いられているので、液晶表示装置の視野角特性等の光学特性を改善することができる。したがって、液晶表示装置の高精細化を実現できる。 According to such a configuration, an optical compensation film excellent in optical compensation performance is applied as the transparent protective film of the polarizing plate. For example, when applied to a liquid crystal display device, the viewing angle is increased and the contrast is increased. A polarizing plate capable of realizing high image quality of the liquid crystal display device such as improvement can be obtained.
(Liquid crystal display device)
The liquid crystal display device includes a liquid crystal cell and two polarizing plates arranged so as to sandwich the liquid crystal cell. Note that the liquid crystal cell is a cell in which a liquid crystal substance is filled between a pair of electrodes, and by applying a voltage to the electrodes, the alignment state of the liquid crystal is changed and the amount of transmitted light is controlled. Since such a liquid crystal display device uses a polarizing plate excellent in optical compensation performance and the like, optical characteristics such as viewing angle characteristics of the liquid crystal display device can be improved. Therefore, high definition of the liquid crystal display device can be realized.
　また、液晶表示装置としては、具体的には、例えば、反射型、透過型、及び半透過型のものが挙げられ、また、ＴＮ型、ＳＴＮ型、ＯＣＢ型、ＨＡＮ型、ＶＡ型（ＰＶＡ型、ＭＶＡ型）、ＩＰＳ型等の各種駆動方式のものが挙げられる。この中でも、本実施形態による光学補償フィルムを備えた偏光板は、ＩＰＳ型の液晶表示装置で好適に用いられる。 Specific examples of the liquid crystal display device include a reflective type, a transmissive type, and a transflective type, and also include a TN type, an STN type, an OCB type, a HAN type, and a VA type (PVA type). , MVA type), IPS type and the like. Among these, the polarizing plate provided with the optical compensation film according to the present embodiment is suitably used in the IPS liquid crystal display device.
　本実施形態による光学補償フィルムを備えた偏光板を市販のＩＰＳ（In Plane Switching）モード型の液晶表示装置に組み込むことによって、視認性に優れ、優れたカラーシフト、コーナームラ、正面コントラスト特性を有する液晶表示装置を作製することができる。 By incorporating the polarizing plate provided with the optical compensation film according to the present embodiment into a commercially available IPS (In-Plane-Switching) mode type liquid crystal display device, it has excellent visibility, excellent color shift, corner unevenness, and front contrast characteristics. A liquid crystal display device can be manufactured.
　ここで、ＩＰＳモードとは、フリンジ電場スイッチング（ＦＦＳ：Fringe-Field Switching）モードも含み、ＩＰＳモードと同様に、本実施形態による光学補償フィルムを備えた偏光板を組み込むことができ、同様の効果をもつ液晶表示装置を作製することができる。 Here, the IPS mode includes a fringe electric field switching (FFS) mode, and similarly to the IPS mode, a polarizing plate including the optical compensation film according to the present embodiment can be incorporated, and similar effects can be obtained. A liquid crystal display device having can be manufactured.
　ＩＰＳモード型の液晶表示装置における液晶パネルの液晶層は、初期状態で基板面と平行なホモジニアス配向で、且つ基板と平行な平面で液晶層のダイレクターは電圧無印加時で電極配線方向と平行または幾分角度を有する。そして、電圧印加時で液晶層のダイレクターの向きが、電圧の印加に伴い電極配線方向と垂直な方向に移行し、液晶層のダイレクター方向が、電圧無印加時のダイレクター方向に比べて４５°電極配線方向に傾斜したとき、当該電圧印加時の液晶層は、まるで１／２波長板のように偏光の方位角を９０°回転させ、出射側偏光板の透過軸と偏光の方位角が一致して白表示となる。 The liquid crystal layer of the liquid crystal panel in the IPS mode type liquid crystal display device is homogeneously aligned in parallel with the substrate surface in the initial state, and the director of the liquid crystal layer in the plane parallel to the substrate is parallel to the electrode wiring direction when no voltage is applied. Or somewhat have an angle. Then, the direction of the director of the liquid crystal layer when a voltage is applied shifts in a direction perpendicular to the electrode wiring direction with the application of the voltage, and the director direction of the liquid crystal layer is compared to the direction of the director when no voltage is applied. When tilted in the direction of 45 ° electrode wiring, the liquid crystal layer when the voltage is applied rotates the azimuth angle of the polarization by 90 ° like a half-wave plate, and the transmission axis of the output side polarizing plate and the azimuth angle of the polarization Match and the display is white.
　一般に、液晶層の厚みは一定であるが、横電界駆動であるため、液晶層の厚みに若干凹凸を設ける方がスイッチングに対する応答速度を上げることができるとも考えられるが、本実施形態による光学補償フィルムを備えた偏光板を組み込むことによって、液晶層の厚みが一定でない場合であっても、その効果を最大限生かすことができるものである。 In general, the thickness of the liquid crystal layer is constant, but since it is driven by a lateral electric field, it may be possible to increase the response speed with respect to switching by slightly increasing the thickness of the liquid crystal layer. By incorporating a polarizing plate provided with a film, the effect can be maximized even when the thickness of the liquid crystal layer is not constant.
　したがって、液晶層の厚みの変化に対し影響が少ないが、２～６μｍであることが好ましく、３～５．５μｍであることがより好ましい。そうすることによって、すぐれた性能を効果的に発揮できる液晶層となる。 Therefore, although there is little influence on the change in the thickness of the liquid crystal layer, the thickness is preferably 2 to 6 μm, more preferably 3 to 5.5 μm. By doing so, a liquid crystal layer that can effectively exhibit excellent performance is obtained.
　本発明によれば、光学補償性能に優れた光学補償フィルムを具備する偏光板を用いるので、視野角の拡大やコントラスト等が向上された、高画質な液晶表示装置を提供することができる。 According to the present invention, since a polarizing plate having an optical compensation film excellent in optical compensation performance is used, it is possible to provide a high-quality liquid crystal display device with an improved viewing angle and contrast.
　つぎに、本発明の実施例を比較例と共に説明するが、本発明は、これらの実施例に限定されるものではない。
実施例１
　透明性セルロースエステル系樹脂フィルム基材としては、セルロースアセテートプロピオネートフィルム（ＣＡＰ、商品名ＫＣ－４ＫＲ、コニカミノルタオプト社製）を使用した。この樹脂フィルムの膜厚は６０μｍであり、幅は１．５ｍであった。
（バックコート層形成用塗布組成物）
　セルロースアセテートプロピオネート（ＣＡＰ）　　　　　０．１質量部
　（アセチル基置換度０．０４、プロピオニル基置換度２．４、
　　総アシル基置換度２．４４）
　プロピレングリコールモノメチルエーテルアセテート　　　　２０質量部
　（溶剤１：ＰＧＭＥＡ、沸点：１４６℃、ＳＰ値：９．６）
　イソプロピルアルコール　　　　　　　　　　　　　　　　　８０質量部
　（溶剤２：ＩＰＡ、沸点：８２．４℃、ＳＰ値：１１．５）
　シリカ微粒子の２％イソプロピルアルコール分散液　　　　０．８質量部
　（シーホスターＫＥ－Ｐ５０、株式会社日本触媒製、平均粒径：５００ｎｍ）
　上記のバックコート層形成用塗布組成物をセルロースアセテートプロピオネートフィルムの片面に、ワイヤーバー（＃５）で塗布し、温度８０℃で、３０秒間乾燥し、バックコート層を形成した。バックコート層の膜厚は、０．２μｍであった。
（接合用中間層形成用塗布組成物）
　ウレタンアクリレートオリゴマー　　　　　　　　　　　　　１３質量部
　（ＵＶ－７５１０Ｂ　日本合成化学株式会社））
　プロピレングリコールモノメチルエーテル　　　　　　　　２９０質量部
　イソプロピルアルコール　　　　　　　　　　　　　　　　６８５質量部
　光重合開始剤　　　　　　　　　　　　　　　　　　　　０．０５質量部
　（ルシリンＴＰＯ（バスフ株式会社製）
　上記の中間層形成用塗布組成物を、セルロースアセテートプロピオネートフィルムの他面に、ワイヤーバー（＃３）で塗布し、温度８０℃で、３０秒間乾燥後、紫外線を１２０ｍＪ／ｍｍを１０秒照射して硬化した。乾燥後の接合用中間層の膜厚は、０．５μｍであった。
（重合性液晶層形成用塗布組成物）
　紫外線重合性液晶材料　　　　　　　　　　　　　　　　　　２５質量部
　（ＵＣＬ０１８　大日本インキ化学工業株式会社製）
　プロピレングリコールモノメチルエーテルアセテート　　　　８０質量部
　光重合開始剤　　　　　　　　　　　　　　　　　　　　０．０４質量部
　（ルシリンＴＰＯ、バスフ株式会社製）
　ヒンダードアミン　　　　　　　　　　　　　　　　　　０．０２質量部
　（ＬＳ－７６５、三共ライフテック株式会社製）
　上記の重合性液晶層形成用塗布組成物をダイコータにより上記接合用中間層の表面上にウェット１２μｍの厚みで塗布した。その後、温度１００℃の恒温槽中で２分間加熱し、棒状液晶化合物を配向させて、液晶化合物を含む光学異方性層を形成した。光学異方性層の膜厚は、２μｍであった。 Next, examples of the present invention will be described together with comparative examples, but the present invention is not limited to these examples.
Example 1
As the transparent cellulose ester-based resin film substrate, a cellulose acetate propionate film (CAP, trade name KC-4KR, manufactured by Konica Minolta Opto) was used. The resin film had a thickness of 60 μm and a width of 1.5 m.
(Coating composition for backcoat layer formation)
Cellulose acetate propionate (CAP) 0.1 part by mass (acetyl group substitution degree 0.04, propionyl group substitution degree 2.4,
Total acyl group substitution degree 2.44)
20 parts by mass of propylene glycol monomethyl ether acetate (solvent 1: PGMEA, boiling point: 146 ° C., SP value: 9.6)
80 parts by mass of isopropyl alcohol (solvent 2: IPA, boiling point: 82.4 ° C, SP value: 11.5)
0.8 part by mass of 2% isopropyl alcohol dispersion of silica fine particles (Seahoster KE-P50, manufactured by Nippon Shokubai Co., Ltd., average particle size: 500 nm)
The back coating layer forming coating composition was applied to one side of a cellulose acetate propionate film with a wire bar (# 5) and dried at a temperature of 80 ° C. for 30 seconds to form a back coating layer. The film thickness of the back coat layer was 0.2 μm.
(Coating composition for forming intermediate layer for bonding)
13 parts by mass of urethane acrylate oligomer (UV-7510B Nippon Synthetic Chemical Co., Ltd.))
Propylene glycol monomethyl ether 290 parts by mass Isopropyl alcohol 685 parts by mass Photopolymerization initiator 0.05 parts by mass (Lucirin TPO (manufactured by BASF Corporation)
The intermediate layer-forming coating composition is applied to the other side of the cellulose acetate propionate film with a wire bar (# 3), dried at a temperature of 80 ° C. for 30 seconds, and then irradiated with ultraviolet rays at 120 mJ / mm for 10 seconds. Cured by irradiation. The thickness of the bonding intermediate layer after drying was 0.5 μm.
(Coating composition for forming a polymerizable liquid crystal layer)
25 parts by mass of UV-polymerizable liquid crystal material (UCL018 manufactured by Dainippon Ink & Chemicals, Inc.)
Propylene glycol monomethyl ether acetate 80 parts by mass Photopolymerization initiator 0.04 parts by mass (Lucirin TPO, manufactured by Bassf Corporation)
0.02 parts by mass of hindered amine (LS-765, manufactured by Sankyo Lifetech Co., Ltd.)
The above-mentioned coating composition for forming a polymerizable liquid crystal layer was applied to the surface of the above-mentioned bonding intermediate layer with a thickness of 12 μm by a die coater. Then, it heated for 2 minutes in a 100 degreeC thermostat, the rod-shaped liquid crystal compound was orientated, and the optically anisotropic layer containing a liquid crystal compound was formed. The film thickness of the optically anisotropic layer was 2 μm.
　なお、下記の表２に、実施例１におけるバックコート層形成用塗布組成物の使用溶剤１の種類、そのＳＰ値、および沸点（℃）、並びに同使用溶剤２の種類、そのＳＰ値、および沸点（℃）、さらには、使用溶剤１と使用溶剤２の溶剤混合比を、まとめて記載した。 In Table 2 below, the type, the SP value, and the boiling point (° C.) of the solvent 1 used in the coating composition for forming a backcoat layer in Example 1, and the type of the solvent 2, the SP value, and The boiling point (° C.) and the solvent mixing ratio of the solvent 1 and the solvent 2 are collectively described.
　こうして得られた本実施例１による光学補償フィルムのバックコート層の基層表面の中心線平均粗さ（Ｒａ）を、温度２３℃、湿度５０±５％ＲＨの条件下において、３次元表面構造解析顕微鏡（ｚｙｇｏ Ｎｅｗ Ｖｉｅｗ ５０００、キャノン販売株式会社製）を用い、対物レンズ５０倍、イメージズーム１．０倍で測定した。 The center line average roughness (Ra) of the base layer surface of the back coat layer of the optical compensation film obtained in this Example 1 in this way was analyzed under a condition of a temperature of 23 ° C. and a humidity of 50 ± 5% RH. Using a microscope (zygo New View 5000, manufactured by Canon Sales Co., Ltd.), measurement was performed with an objective lens of 50 times and an image zoom of 1.0 times.
　このとき、５０ｎｍ以上のピークがある微粒子存在領域部分をカットした、微粒子が存在しない領域部分であるバックコート層基層表面について中心線平均粗さ（Ｒａ）の測定を行ったところ、中心線平均粗さ（Ｒａ）は、５ｎｍであり、得られた結果を下記の表３に示した。
実施例２
　上記実施例１の場合と同様に実施するが、上記実施例１の場合と異なる点は、バックコート層形成用塗布組成物の溶剤として、溶剤１：メチルエチルケトン（ＭＥＫ、沸点：８０℃、ＳＰ値：９．３）１０質量部、および溶剤２：メタノール（ＭｅＯＨ、沸点：６４．６℃、ＳＰ値：１４．５）９０質量部を、下記の表２に示すように、１０：９０の割合で使用した点にある。 At this time, when the center line average roughness (Ra) was measured on the surface of the backcoat layer base layer which was a region portion where the fine particle existing region having a peak of 50 nm or more was cut and the fine particle was not present, the center line average roughness was measured. The thickness (Ra) was 5 nm, and the obtained results are shown in Table 3 below.
Example 2
Although it carries out similarly to the case of the said Example 1, a different point from the case of the said Example 1 is a solvent 1: methyl ethyl ketone (MEK, boiling point: 80 degreeC, SP value) as a solvent of the coating composition for backcoat layer formation. 9.3) 10 parts by mass, and solvent 2: methanol (MeOH, boiling point: 64.6 ° C., SP value: 14.5) 90 parts by mass, as shown in Table 2 below, in a ratio of 10:90 It is in the point used in.
　こうして得られた本実施例２による光学補償フィルムのバックコート層の基層表面の中心線平均粗さ（Ｒａ）を、上記実施例１の場合と同様に測定したところ、中心線平均粗さ（Ｒａ）は、２ｎｍであり、得られた結果を下記の表３にあわせて示した。
実施例３
　上記実施例１の場合と同様に実施するが、上記実施例１の場合と異なる点は、バックコート層形成用塗布組成物の溶剤として、溶剤１：酢酸エチル（沸点：７８℃、ＳＰ値：８．９）３０質量部、および溶剤２：メタノール（ＭｅＯＨ、沸点：６４．６℃、ＳＰ値：１４．５）７０質量部を、下記の表２に示すように、３０：７０の割合で使用した点にある。 When the center line average roughness (Ra) of the base layer surface of the back coat layer of the optical compensation film obtained in this Example 2 was measured in the same manner as in Example 1, the center line average roughness (Ra ) Is 2 nm, and the obtained results are shown in Table 3 below.
Example 3
Although it carries out similarly to the case of the said Example 1, the point different from the case of the said Example 1 is a solvent 1: ethyl acetate (boiling point: 78 degreeC, SP value :) as a solvent of the coating composition for backcoat layer formation. 8.9) 30 parts by mass and solvent 2: 70 parts by mass of methanol (MeOH, boiling point: 64.6 ° C., SP value: 14.5) at a ratio of 30:70 as shown in Table 2 below. It is in the point used.
　こうして得られた本実施例３による光学補償フィルムのバックコート層の基層表面の中心線平均粗さ（Ｒａ）を、上記実施例１の場合と同様に測定したところ、中心線平均粗さ（Ｒａ）は、１０ｎｍであり、得られた結果を下記の表３にあわせて示した。
実施例４
　上記実施例１の場合と同様に実施するが、上記実施例１の場合と異なる点は、バックコート層形成用塗布組成物の微粒子として、シリカ微粒子の２％イソプロピルアルコール分散液（シーホスターＫＥ－Ｐ１０、株式会社日本触媒製、平均粒径：１００ｎｍ）０．８質量部を使用した点にある。
実施例５
　上記実施例１の場合と同様に実施するが、上記実施例１の場合と異なる点は、バックコート層形成用塗布組成物の微粒子として、シリカ微粒子の２％イソプロピルアルコール分散液（シーホスターＫＥ－Ｐ１００、株式会社日本触媒製、平均粒径：１０００ｎｍ）０．８質量部を使用した点にある。
実施例６
　上記実施例１の場合と同様に実施するが、上記実施例１の場合と異なる点は、バックコート層形成用塗布組成物の微粒子として、アクリル微粒子の２％イソプロピルアルコール分散液（ＲＳＰ－３０２１Ｄ、株式会社東洋インキ製、平均粒径：５００ｎｍ）０．８質量部を使用した点にある。
実施例７
　上記実施例１の場合と同様に実施するが、上記実施例１の場合と異なる点は、透明性セルロースエステル系樹脂フィルム基材として、セルローストリアセテートフィルム（ＴＡＣ、商品名ＫＣ４ＵＹＷ、コニカミノルタオプト社製）を使用した点にある。この樹脂フィルムの膜厚は６０μｍであり、幅は１．５ｍであった。
比較例１
　比較のために、上記実施例１の場合とは、バックコート層形成用塗布組成物の溶剤が異なるようにして、実施した。すなわち、バックコート層形成用塗布組成物の溶剤として、溶剤１：プロピレングリコールモノメチルエーテルアセテート（ＰＧＭＥＡ、沸点：１４６℃、ＳＰ値：９．６）５質量部、および溶剤２：イソプロピルアルコール（ＩＰＡ、沸点：８２．４℃、ＳＰ値：１１．５）９５質量部を、下記の表２に示すように、５：９５の割合で使用した点にある。 When the center line average roughness (Ra) of the base layer surface of the backcoat layer of the optical compensation film obtained in this Example 3 was measured in the same manner as in Example 1, the center line average roughness (Ra ) Is 10 nm, and the obtained results are shown in Table 3 below.
Example 4
The same procedure as in Example 1 is performed except that the fine particle of the backcoat layer forming coating composition is a 2% isopropyl alcohol dispersion of silica fine particles (Seahoster KE-P10). , Manufactured by Nippon Shokubai Co., Ltd., average particle diameter: 100 nm), 0.8 parts by mass.
Example 5
The same procedure as in Example 1 is carried out, but the difference from Example 1 is that a 2% isopropyl alcohol dispersion of silica fine particles (Seahoster KE-P100) is used as the fine particles of the coating composition for backcoat layer formation. , Manufactured by Nippon Shokubai Co., Ltd., average particle size: 1000 nm), 0.8 parts by mass.
Example 6
The same procedure as in Example 1 is carried out, but the difference from Example 1 is that a 2% isopropyl alcohol dispersion (RSP-3021D, acrylic fine particles) is used as the fine particles of the coating composition for forming the backcoat layer. This is in that 0.8 parts by mass of Toyo Ink Co., Ltd. (average particle size: 500 nm) was used.
Example 7
Although it carries out similarly to the case of the said Example 1, a different point from the case of the said Example 1 is a cellulose triacetate film (TAC, brand name KC4UYW, the Konica Minolta Opto company make) as a transparent cellulose-ester-type resin film base material. ) Is used. The resin film had a thickness of 60 μm and a width of 1.5 m.
Comparative Example 1
For comparison, it was carried out with the solvent of the coating composition for backcoat layer formation being different from that in Example 1 above. That is, as a solvent for the coating composition for forming a backcoat layer, solvent 1: propylene glycol monomethyl ether acetate (PGMEA, boiling point: 146 ° C., SP value: 9.6) 5 parts by mass, and solvent 2: isopropyl alcohol (IPA, Boiling point: 82.4 ° C., SP value: 11.5) As shown in Table 2 below, 95 parts by mass is used at a ratio of 5:95.
　こうして得られた比較例１による光学補償フィルムのバックコート層の基層表面の中心線平均粗さ（Ｒａ）を、上記実施例１の場合と同様に測定したところ、中心線平均粗さ（Ｒａ）は、１ｎｍであり、得られた結果を下記の表３にあわせて示した。
比較例２
　比較のために、上記実施例１の場合とは、バックコート層形成用塗布組成物の溶剤が異なるようにして、実施した。すなわち、バックコート層形成用塗布組成物の溶剤として、溶剤１：シクロヘキサノン（沸点：１５５℃、ＳＰ値：９．６）９０質量部、および溶剤２：ノルマルプロピルアルコール（ＮＰＡ、沸点：９７℃、ＳＰ値：１２）１０質量部を、下記の表２に示すように、９０：１０の割合で使用した点にある。 When the center line average roughness (Ra) of the base layer surface of the back coat layer of the optical compensation film according to Comparative Example 1 thus obtained was measured in the same manner as in Example 1, the center line average roughness (Ra) was measured. Is 1 nm, and the obtained results are shown in Table 3 below.
Comparative Example 2
For comparison, it was carried out with the solvent of the coating composition for backcoat layer formation being different from that in Example 1 above. That is, as a solvent for the coating composition for forming a backcoat layer, solvent 1: cyclohexanone (boiling point: 155 ° C., SP value: 9.6) 90 parts by mass, and solvent 2: normal propyl alcohol (NPA, boiling point: 97 ° C., SP value: 12) As shown in Table 2 below, 10 parts by mass is used at a ratio of 90:10.
　こうして得られた比較例２による光学補償フィルムのバックコート層の基層表面の中心線平均粗さ（Ｒａ）を、上記実施例１の場合と同様に測定したところ、中心線平均粗さ（Ｒａ）は、２０ｎｍであり、得られた結果を下記の表３にあわせて示した。
比較例３
　上記実施例１の場合と同様に実施するが、上記実施例１の場合と異なる点は、バックコート層形成用塗布組成物の微粒子として、シリカ微粒子の２％イソプロピルアルコール分散液（ＨＰＳ－５００、株式会社東亞合成製、平均粒径：５０００ｎｍ）０．８質量部を使用した点にある。
（評価試験）
　上記作製した、実施例１～７及び比較例１～３による各光学補償フィルムについて、下記の方法により光学性能を評価した。
〔ヘイズの測定〕
　上記実施例１～７、および比較例１～３で得られた光学補償フィルムの各試料について、ヘイズ測定器（ＮＤＨ－２０００、東京電色工業株式会社製）を使用して、ヘイズ値を３回ずつ測定し、その平均値を各光学補償フィルムのヘイズ値とした。得られた結果を下記の表３にあわせて示した。
〔リタデーションムラの測定〕
　上記実施例１～７、および比較例１～３で得られた各光学補償フィルムについて、常温で、１週間保管後のロールサンプルからＡサイズの試料を切り出し、それぞれの試料についてクロスニコル条件化で、目視によりリタデーションムラの評価を、下記の基準により行った。得られた結果を下記の表３にあわせて示した。 When the center line average roughness (Ra) of the base layer surface of the back coat layer of the optical compensation film according to Comparative Example 2 thus obtained was measured in the same manner as in Example 1, the center line average roughness (Ra) was measured. Is 20 nm, and the obtained results are shown in Table 3 below.
Comparative Example 3
The same procedure as in Example 1 was performed except that the fine particle of the coating composition for forming the backcoat layer was a 2% isopropyl alcohol dispersion of silica fine particles (HPS-500, Toagosei Co., Ltd., average particle size: 5000 nm) is 0.8 mass part.
(Evaluation test)
The optical performance of each of the optical compensation films prepared in Examples 1 to 7 and Comparative Examples 1 to 3 was evaluated by the following method.
[Measurement of haze]
For each sample of the optical compensation film obtained in Examples 1 to 7 and Comparative Examples 1 to 3, a haze value of 3 was obtained using a haze measuring device (NDH-2000, manufactured by Tokyo Denshoku Industries Co., Ltd.). The average value was measured as the haze value of each optical compensation film. The obtained results are shown in Table 3 below.
[Measurement of retardation unevenness]
For each of the optical compensation films obtained in Examples 1 to 7 and Comparative Examples 1 to 3, a sample of A size was cut out from a roll sample after storage for 1 week at room temperature, and each sample was subjected to crossed Nicol conditions. The retardation unevenness was visually evaluated based on the following criteria. The obtained results are shown in Table 3 below.
　◎：押し跡、変形によるムラが全く無いもの
　○：若干のムラはあるが、有害性の無いもの
　×：ムラが目立ち、有害性があるもの
〔耐久処理後のリタデーションムラの測定〕
　上記実施例１～７、および比較例１～３で得られた各光学補償フィルムについて、温度５０℃、湿度９０％ＲＨの高湿条件下で、各光学補償フィルム試料を重ね合わせて２００ｇの荷重をかけて、３時間、耐久処理を行った後、それぞれの試料についてクロスニコル条件化で、目視によりリタデーションムラの評価を、上記の基準により行った。得られた結果を下記の表３にあわせて示した。
〔ブロッキングの測定〕
　上記実施例１～７、および比較例１～３で得られた各光学補償フィルムについて、温度５０℃、湿度９０％ＲＨの高湿条件下で、各光学補償フィルム試料を重ね合わせて２００ｇの荷重をかけて３時間、耐久処理を行った後、それぞれの試料についてクロスニコル条件化で、目視により貼り付き（ブロッキング性）の評価を、上記の基準により行った。得られた結果を下記の表３にあわせて示した。 ◎: There is no unevenness due to imprints and deformations ○: There is some unevenness but no harm ×: Unevenness is noticeable and harmful (measurement of retardation unevenness after endurance treatment)
About each optical compensation film obtained in Examples 1 to 7 and Comparative Examples 1 to 3, each optical compensation film sample was overlaid under a high humidity condition of a temperature of 50 ° C. and a humidity of 90% RH, and a load of 200 g was obtained. After performing the durability treatment for 3 hours, the retardation unevenness was visually evaluated for each sample under the crossed Nicol condition according to the above criteria. The obtained results are shown in Table 3 below.
[Measurement of blocking]
About each optical compensation film obtained in Examples 1 to 7 and Comparative Examples 1 to 3, each optical compensation film sample was overlaid under a high humidity condition of a temperature of 50 ° C. and a humidity of 90% RH, and a load of 200 g was obtained. After performing durability treatment for 3 hours, the sticking (blocking property) was visually evaluated for each sample under crossed Nicol conditions according to the above criteria. The obtained results are shown in Table 3 below.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　上記表３の結果から明らかなように、本発明の実施例１～７で得られた光学補償フィルムは、バックコート層基層表面の微粒子が存在しない領域の中心線平均粗さ（Ｒａ）を、所定の比較的粗い範囲に制御することにより、いずれも光学補償フィルムのブロッキング（貼り付き）を改善することができ、これにより、光学補償フィルムについて、透明性フィルム基材及び液晶化合物を含む光学異方性層（液晶層）の変形によるリタデーションムラを抑制できるとともに、すぐれた表面平滑性（低ヘイズ）を有するものであった。 As is clear from the results in Table 3 above, the optical compensation films obtained in Examples 1 to 7 of the present invention have a center line average roughness (Ra) in a region where no fine particles exist on the backcoat layer base layer surface. By controlling to a predetermined relatively rough range, it is possible to improve the blocking (adhesion) of the optical compensation film. As a result, the optical compensation film includes an optical film including a transparent film substrate and a liquid crystal compound. It was possible to suppress retardation unevenness due to deformation of the isotropic layer (liquid crystal layer) and to have excellent surface smoothness (low haze).
　これに対し、上記比較例１で得られた光学補償フィルムは、バックコート層基層表面の微粒子が存在しない領域の中心線平均粗さ（Ｒａ）が小さいために、低ヘイズを有するものであるが、光学異方性層（液晶層）の変形によるリタデーションムラ、特に、耐久処理後のリタデーションムラを抑制することはできないものであった。また、上記比較例２で得られた光学補償フィルムは、バックコート層基層表面の微粒子が存在しない領域の中心線平均粗さ（Ｒａ）が大きいために、ヘイズ値が非常に高いものであった。さらに上記比較例３で得られた光学補償フィルムは、バックコート層に含まれる微粒子の平均粒子径が非常に大きいものであるため、ヘイズ値が非常に高いものであり、光学補償フィルムの性能として満足できるレベルのものは得られなかった。 On the other hand, the optical compensation film obtained in Comparative Example 1 has a low haze because the center line average roughness (Ra) in the region where the fine particles on the backcoat layer base layer surface are not present is small. The retardation unevenness due to the deformation of the optically anisotropic layer (liquid crystal layer), particularly the retardation unevenness after the durability treatment cannot be suppressed. Further, the optical compensation film obtained in Comparative Example 2 had a very high haze value because the center line average roughness (Ra) in the region where fine particles on the backcoat layer base layer surface were not present was large. . Furthermore, since the optical compensation film obtained in Comparative Example 3 has a very large average particle size of the fine particles contained in the backcoat layer, it has a very high haze value. A satisfactory level was not obtained.

Claims (5)

  1. 　セルロースエステル系樹脂透明性フィルム基材の片面に、配向された液晶化合物を含む光学異方性層が設けられ、同透明性フィルム基材の他面に、セルロースエステル系樹脂バインダーと微粒子とを含有するバックコート層が設けられている光学補償フィルムにおいて、バックコート層に含まれる微粒子の粒径が１μｍ以下であり、バックコート層基層表面の微粒子の存在しない領域の中心線平均粗さ（Ｒａ）が、２～１０ｎｍの範囲であることを特徴とする、光学補償フィルム。 An optically anisotropic layer containing an oriented liquid crystal compound is provided on one side of the cellulose ester resin transparent film substrate, and the cellulose ester resin binder and fine particles are contained on the other surface of the transparent film substrate. In the optical compensation film provided with the back coat layer, the particle size of the fine particles contained in the back coat layer is 1 μm or less, and the center line average roughness (Ra) of the region where the fine particles are not present on the back coat layer base layer surface Is an optical compensation film characterized in that it is in the range of 2 to 10 nm.
  2. 　透明性フィルム基材の片面と、液晶化合物を含む光学異方性層との間に、接合用中間層が設けられていることを特徴とする、請求項１に記載の光学補償フィルム。 The optical compensation film according to claim 1, wherein a bonding intermediate layer is provided between one side of the transparent film substrate and the optically anisotropic layer containing a liquid crystal compound.
  3. 　セルロースエステル系樹脂透明性フィルム基材が、セルロースアセテートプロピオネートフィルムであることを特徴とする、請求項１または２に記載の光学補償フィルム。 The optical compensation film according to claim 1 or 2, wherein the cellulose ester-based resin transparent film substrate is a cellulose acetate propionate film.
  4. 　請求項１から３のいずれか１項に記載の光学補償フィルムを有することを特徴とする偏光板。 A polarizing plate comprising the optical compensation film according to any one of claims 1 to 3.
  5. 　請求項４に記載の偏光板を有することを特徴とする液晶表示装置。 A liquid crystal display device comprising the polarizing plate according to claim 4.
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