JP2009139859A - Method for manufacturing optical compensation film, optical compensation film, polarizing plate and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical compensation film having excellent quality characteristics by improving the surface state of the optical compensation film and reducing bright spot defects. <P>SOLUTION: The method for manufacturing an optical compensation film comprises subjecting a transparent support 10 to an adhesiveness imparting treatment, then applying a composition 16 for forming an alignment layer to form an alignment layer 18, and applying a liquid crystal compound containing a liquid crystal compound thereon to form an optically anisotropic layer 20, wherein the concentration of the solid content of the coating liquid containing the composition 16 for forming an alignment layer ranges from 0.5 to 2.0 mass%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an optical compensation film, and in particular, a method for producing an optical compensation film for improving the surface shape of an alignment film forming layer, an optical compensation film obtained by the production method, a polarizing plate, and a liquid crystal display Relates to the device.

  A liquid crystal display device is employed as a flat image display device (FPD). The liquid crystal display device includes a sheet material (optical film) having an optical function such as a liquid crystal cell, a polarizing plate, an optical compensation film (retardation plate), and an antireflection film.

  The polarizing plate is generally composed of a polarizing film and two transparent protective films provided on both sides thereof. The polarizing film is generally obtained by impregnating polyvinyl alcohol with an aqueous solution of iodine or a dichroic dye and stretching it uniaxially.

  The optical compensation sheet has a function of improving the display quality of the liquid crystal display device by eliminating image coloring and widening the viewing angle, and is therefore used in various liquid crystal display devices. In recent years, as an optical compensation sheet, an optical compensation sheet having an optically anisotropic layer formed of a liquid crystalline molecule (particularly a discotic liquid crystalline molecule) on a transparent support instead of a conventionally used stretched birefringent film. It is proposed to use. This optically anisotropic layer is formed by aligning liquid crystalline molecules and fixing the alignment state. By using liquid crystal molecules, particularly discotic liquid crystal molecules, optical compensation sheets having various optical characteristics corresponding to various display modes of the liquid crystal cell can be produced.

  For example, TN mode liquid crystal cell optical compensation sheet, IPS mode or FLC mode liquid crystal cell optical compensation sheet, OCB mode or HAN mode liquid crystal cell optical compensation sheet, STN mode liquid crystal cell optical compensation sheet, VA mode liquid crystal An optical compensation sheet for cells has been proposed. Furthermore, in order to reduce the weight of the liquid crystal display device, an integrated elliptical polarizing plate using an optical compensation sheet as one protective film of the polarizing plate has been proposed.

  Further, the antireflection film is disposed on the surface of the display in an image display device such as a liquid crystal display device (LCD) in order to prevent a decrease in contrast due to reflection of external light or reflection of an image.

  Protective film for polarizing plate, transparent support for optical compensation sheet, base material for antireflection film, excellent light transmission, optical non-orientation, excellent physical and mechanical properties, and low temperature and humidity changes The cellulose ester film represented by the cellulose acetate film which has this is employ | adopted.

  In general, in polarizing plates and optical compensation sheets, a polarizing film and an optically anisotropic layer are provided on a cellulose ester film, which is a transparent support, via an adhesive layer and an alignment film (usually polyvinyl alcohol: PVA). Moreover, in an antireflection film or the like, a polyfunctional monomer compound containing a polymerizable group is formed as a coating on the cellulose ester film.

  As a method for providing an optical film having excellent quality characteristics, a method using a modified PVA compound having a characteristic of easily aligning a discotic liquid crystalline compound as a material for forming an alignment film (Patent Document 1) is disclosed. Moreover, when applying the composition for alignment films on a transparent support, the surface temperature of the coating liquid layer is maintained at 30 to 60 ° C. and dried to make the alignment film formation layer less likely to be uneven (Patent Literature). 2) is disclosed.

Furthermore, when a carboxylic acid compound containing a polar group is added to the alignment film forming composition to be coated on the transparent support provided with adhesion, the adhesion of the film and the good surface of the optical compensation film are extremely stable. An alignment film forming method (Patent Document 3) that can achieve both shapes is disclosed. In addition, an optical film having excellent quality characteristics can be formed by the alkali saponification method (Patent Documents 4, 5, and 6) of the transparent support having excellent adhesion to the alignment film forming layer (Patent Documents 4, 5, and 6). Is disclosed.
JP 9-152509 A Japanese Patent Laid-Open No. 2000-2809 Japanese Patent Application Laid-Open No. 2004-354962 JP 2004-182893 A JP 2004-225002 A JP 2006-335800 A

  However, in the method described in the above-mentioned patent document, drying unevenness occurs in drying after applying the composition for forming an alignment film, and spot failure due to this drying unevenness occurs, and a satisfactory optical compensation film can be obtained. It wasn't. In order to suppress the occurrence of unevenness in drying, it has been studied to reduce the amount of solids in the composition for forming an alignment film. However, if the amount of solids is reduced, it is difficult to apply, the amount of solvent is increased, and the concentration of solids is increased. When the value of is small, the hydrophobic compound is dissolved in the solvent, so that it is included in the formed alignment film, and an alignment defect is finally generated in the finally formed optical anisotropic layer.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an optical compensation film having excellent quality characteristics. Specifically, (1) the unevenness of the coating thickness of the alignment film forming layer is alleviated to improve the surface shape of the optical compensation film comprising the liquid crystalline compound layer, and (2) the surface quality (hardness) of the alignment film forming layer. ) Is suppressed, dust generation from the alignment film forming layer due to the rubbing treatment is suppressed, and the bright spot defect of the optical compensation film is reduced.

  In order to achieve the above object, claim 1 of the present invention forms an alignment film by applying a composition for forming an alignment film by applying an adhesion imparting treatment on a transparent support, and forming an alignment film thereon. In the method for producing an optical compensation film formed by applying a liquid crystalline compound containing a liquid crystalline compound to form an optically anisotropic layer, the solid content concentration of the coating liquid containing the alignment film forming composition is 0.5 to Provided is a method for producing an optical compensation film, which is 2.0% by mass.

  According to claim 1, since the solid content of the coating liquid containing the composition for forming an alignment film is as small as 0.5 to 2.0% by mass, the alignment film can be flattened, and the bright spot defect, An optical compensation film with few plaque failures can be produced.

  A second aspect of the present invention provides the alignment film forming composition according to the first aspect, wherein the alignment film forming composition contains polyvinyl alcohol and / or modified polyvinyl alcohol as a main component, and the alignment film is coated with the alignment film forming composition. It is a cured film formed by drying.

In the method for producing an optical compensation film of the present invention, it is particularly preferable to use polyvinyl alcohol and / or modified polyvinyl alcohol as the alignment film forming composition. The composition is characterized by containing at least one organic carboxylic acid compound containing at least one polar group.

  According to claim 3, since the composition for forming an alignment film contains an organic carboxylic acid compound containing at least one polar group, the optical anisotropy is obtained after aligning the obtained alignment film by an aligning means. The coated surface of the optical compensation film obtained by coating the layer is good and exhibits an improvement effect that reduces or eliminates optical defects such as white spots.

  A fourth aspect of the present invention is the method according to any one of the first to third aspects, in which the adhesion imparting treatment is performed by (a) applying an alkaline aqueous solution containing at least water, an organic solvent and an alkaline agent to the transparent support; Saponification of the transparent support with the aqueous alkali solution, and a saponification treatment step in which the amount of the plasticizer on the surface of the saponification treatment surface of the transparent support is 0.25 or less as measured by the ATR / IR method. It is a saponification treatment of the body.

  According to claim 4, the cellulose ester film is saponified with an alkaline aqueous solution until the amount of the plasticizer on the surface of the film after saponification is 0.25 or less as measured by the ATR / IR method. The amount of extraction from the cellulose ester film of the hydrophobic extraction component (plasticizer) that becomes an obstacle to crosslinking during the polymerization reaction (crosslinking) of the polyfunctional monomer compound to be contained can be reduced. Therefore, a saponified cellulose ester film that can improve the durability of the coating formed from the polymerization reaction of the polyfunctional monomer compound without taking harsh means such as excessive addition of crosslinking agent, acceleration of heating, and increase of ionizing radiation dose is produced. can do.

In the present invention, the measurement by the ATR / IR method means Attenuated Total Reflection absorption spectroscopy (Standard Chemical Glossary 2nd edition). Specifically, when a transparent material with a large refractive index, such as quartz, is in close contact with a sample (solid or liquid) and incident light is applied at an incident angle from the transparent material side, total reflection occurs, but the reflected light is near the contact surface. The absorption characteristics of the sample are reflected because it is absorbed by a small part of the sample (several μm). A method of obtaining a spectrum by measuring the intensity change of the total reflected light.
[Model used]
NICOLET 4700 (manufactured by Thermo Fisher Scientific)
ATR body (folder): 45 °
Prism: KRS-5 45 °
[Sample conditions]
Size: 1.9cm x 4.5cm
Measurement humidity: 25 ° C 20%
[Measurement data processing]
The ratio of the cellulose ester film from the peak of the plasticizer from the peak and 1370 cm ^-1 of 1490Cm ^-1 In addition, the saponified surface surface refers to the surface of the film surface to a position of a depth of 1 to 2 [mu] m.

  A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the transparent support is a cellulose ester film.

  In the method for producing the optical compensation film of the present invention, it is preferable to use a cellulose ester film as the transparent support.

  A sixth aspect of the present invention is characterized in that in any one of the first to fifth aspects, the liquid crystalline compound contains at least one fluoroaliphatic group-containing polymer represented by the following general formula (1).

In the general formula (1), i and j each represent an integer of 1 or more, meaning that each repeating unit includes i and j types, respectively; M is derived from an ethylenically unsaturated monomer, and k ( k is an integer greater than or equal to 1) types of repeating units; a, b and c are mass percentages representing a polymerization ratio, Σai represents a numerical value of 1 to 98% by mass, Σbj represents 1 to 98% by mass Σck represents a numerical value of 1 to 98% by mass; R ¹¹ and R ¹² each represent a hydrogen atom or a methyl group; X ¹ and X ² represent an oxygen atom, a sulfur atom, or —N (R ¹³ )-, R ¹³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; m1 and m2 each represent an integer of 1 to 6; and n1 represents an integer of 0 to 3.

  According to the sixth aspect, since the liquid crystalline compound contains at least one fluoroaliphatic group-containing polymer represented by the general formula (1), it is possible to suppress the occurrence of spots in the initial stage of drying.

  A seventh aspect provides an optical compensation film produced by the method for producing an optical compensation film according to any one of the first to sixth aspects.

  An eighth aspect is characterized in that, in the seventh aspect, the thickness of the alignment film is 0.07 to 0.35 μm.

  A ninth aspect provides a polarizing plate comprising the optical compensation film according to the seventh or eighth aspect.

  A tenth aspect provides a liquid crystal display device comprising the optical compensation film according to the seventh or eighth aspect.

  The seventh to tenth aspects are an optical compensation film produced by the method for producing an optical compensation film of the present invention, a polarizing plate provided with the optical compensation film, and a liquid crystal display device. Since the optical compensation film produced by the production method of the present invention has a favorable surface shape with few bright spot defects and spot failures, it can be suitably used as a polarizing plate and a liquid crystal display device.

  Moreover, in the manufacturing method of the optical compensation film of this invention, since the solid content concentration of a coating liquid is made small with 0.5-2.0 mass%, the film thickness of the oriented film of the optical compensation film manufactured is 0.07 to 0.35 μm is preferable.

  According to the present invention, by reducing the concentration of the solid content of the coating liquid that is the composition for forming an alignment film, unevenness caused by uneven coating thickness of the alignment film can be reduced, and the quality characteristics are excellent. An optical compensation film can be produced, and the cost can be reduced by reducing the orientation film material.

  Hereinafter, the manufacturing method of the optical compensation film of the present invention, the optical compensation film obtained by the manufacturing method, the polarizing plate using the optical film, and the liquid crystal display device will be described in detail.

  First, a method for producing an optical compensation film and an optical compensation film will be described. As described above, the optical compensation film of the present invention has a layer structure in which a transparent support, an alignment film, and an optically anisotropic layer, which have been subjected to adhesion treatment in advance, are laminated in this order.

[Transparent support]
The transparent support of the present invention is preferably glass or a transparent polymer film. The transparent support preferably has a light transmittance of 80% or more. Examples of the polymer constituting the polymer film include cellulose esters (eg, cellulose mono- or triacylate), and norbornene-based polymers such as ARTON and ZEONEX (both are trade names). Moreover, even if it is a conventionally known polymer such as polycarbonate or polysulfone that easily develops birefringence, it is possible to develop birefringence by modifying the molecule as described in International Publication No. 00/26705 pamphlet. Can be used for the optical compensation film of the present invention. As the polymer film of the present invention, a cellulose ester film is preferable, and a cellulose acetate film is more preferable. The thickness of the transparent support of the present invention is preferably 20 to 500 μm, more preferably 40 to 200 μm, and most preferably 30 to 80 μm.

When using a polymer film for an optical compensation sheet, the polymer film preferably has a desired retardation value. The Re retardation value and Rth retardation value of the polymer film are defined by the following formulas (I) and (II), respectively.
(I) Re = | nx−ny | × d
(II) Rth = {(nx + ny) / 2−nz} × d
In the formulas (I) and (II), nx is the refractive index in the slow axis direction in the film plane (direction in which the refractive index is maximum), ny is the fast axis direction in the film plane (the refractive index is minimum) Nz is the refractive index in the thickness direction of the film, and d is the thickness of the film with the unit of nm.

  The retardation value of the polymer film varies in a preferable range depending on the liquid crystal display device in which the optical compensation sheet is used and the method of use thereof. Usually, the Re retardation value is 0 to 200 nm, and the Rth retardation value is 70 to It is preferable to adjust to the 400 nm range.

  When two optically anisotropic layers are used in the liquid crystal display device, the Rth retardation value of the polymer film is preferably in the range of 70 to 250 nm. When one optically anisotropic layer is used in the liquid crystal display device, the Rth retardation value of the polymer film is preferably in the range of 150 to 400 nm.

  The birefringence (Δn: nx−ny) of the polymer film is preferably in the range of 0.00028 to 0.020. The birefringence {(nx + ny) / 2−nz} in the thickness direction of the polymer film is preferably in the range of 0.001 to 0.04.

  In order to adjust the retardation value of the polymer film, a method of applying an external force such as stretching is generally used. As another method, a retardation increasing agent for adjusting optical anisotropy is optionally added. The

  As the cellulose ester used in the present invention, it is preferable to use a lower fatty acid ester of cellulose. Lower fatty acid means a fatty acid having 6 or less carbon atoms. A cellulose acylate having 2 to 4 carbon atoms is preferred. Cellulose acetate is particularly preferred. Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.

  The viscosity average degree of polymerization (DP) of cellulose acetate is preferably 250 or more, and more preferably 290 or more. Cellulose acetate preferably has a narrow molecular weight distribution of Mw / Mn (Mw is a mass average molecular weight, Mn is a number average molecular weight) by gel permeation chromatography. A specific value of Mw / Mn is preferably 1.0 to 4.0.

  As the transparent support of the present invention, cellulose acetate having an acetylation degree of 55.0 to 62.5% is preferably used. The acetylation degree is more preferably 57.0 to 62.0%, and particularly preferably 59.0 to 61.5%. The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation is determined by measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like).

  In cellulose acetate, the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are not evenly substituted, but the substitution degree at the 6-position tends to be small. In the cellulose acetate used in the present invention, it is preferable that the degree of substitution at the 6-position of cellulose is the same or greater than that at the 2- and 3-positions. The ratio of the substitution degree at the 6-position to the total substitution degree at the 2-position, the 3-position, and the 6-position is preferably 30 to 40%, more preferably 31 to 40%, and more preferably 32 to 40%. Most preferably it is. The substitution degree at the 6-position is preferably 0.88 or more.

  As described above, the retardation increasing agent can be used to increase the retardation in the thickness direction of the transparent support. As the retardation increasing agent, a compound having at least two aromatic rings and a molecular structure that does not sterically hinder the conformation of the two aromatic rings can be used. An aromatic compound is used in 0.01-20 mass parts with respect to 100 mass parts of cellulose esters. The aromatic compound is preferably used in the range of 0.05 to 15 parts by mass, more preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring. Examples of the retardation increasing agent include compounds described in European Patent 0911656A2, JP-A 2000-1111914, 2000-275434, and the like.

  It is preferable to add fine particles to the cellulose ester film of the present invention in order to maintain good scratch resistance and film transportability. They are conventionally used as matting agents, anti-blocking agents or anti-scratching agents. They are not particularly limited as long as they are materials exhibiting the above-mentioned functions, but preferred specific examples of these matting agents include inorganic compounds such as compounds containing silicon, silicon dioxide, titanium oxide, zinc oxide, aluminum oxide, and oxidation. Barium, zirconium oxide, strontium oxide, antimony oxide, tin oxide, tin oxide / antimony, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, etc. More preferred is an inorganic compound containing silicon or zirconium oxide, but silicon dioxide is particularly preferred because the turbidity of the cellulose ester film can be reduced. Also, the surface-treated inorganic fine particles are preferable because of good dispersibility in the cellulose ester. Examples of the treatment method include the method described in JP-A No. 54-57562. Examples of the particles include those described in JP-A No. 2001-151936.

  As the organic compound, for example, polymers such as cross-linked polystyrene, silicone resin, fluororesin and acrylic resin are preferable, and among them, silicone resin is preferably used. Among silicone resins, those having a three-dimensional network structure are particularly preferable.

  A plasticizer can be added to the cellulose ester film of the present invention in order to improve mechanical properties or improve the drying rate. As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Specifically, the content described in detail on page 16 of the Japan Society for Invention and Innovation Technical Report (Technology Number 2001-1745, Invention Association issued on March 15, 2001) is preferably used. The addition amount of the plasticizer is preferably 0.1 to 25% by mass, more preferably 1 to 20% by mass, and most preferably 3 to 15% by mass of the amount of the cellulose ester.

  The cellulose ester film of the present invention is further added with an anti-degradation agent (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) and UV inhibitor. May be. Examples of the degradation inhibitor include compounds described in JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is preferably 0.01 to 1% by mass of the solution (dope) to be prepared, and more preferably 0.01 to 0.2% by mass. As a particularly preferred example of the deterioration preventing agent, butylated hydroxytoluene (BHT) can be mentioned. Examples of the ultraviolet light inhibitor include compounds described in JP-A-7-11055 and JP-A-7-11056. Further, for these details, materials described in detail on pages 17 to 22 of the above-mentioned public technical number 2001-1745 are preferably used.

Furthermore, the hygroscopic expansion coefficient of the cellulose ester film used in the optical compensation sheet of the present invention is preferably 30 × 10 ⁻⁵ /% RH or less. The hygroscopic expansion coefficient is preferably 15 × 10 ⁻⁵ /% RH or less, and more preferably 10 × 10 ⁻⁵ /% RH or less. Moreover, although the one where a hygroscopic expansion coefficient is smaller is preferable, it is a value of 1.0 * 10 < ^-5 > /% RH or more normally. The hygroscopic expansion coefficient indicates the amount of change in the length of the sample when the relative humidity is changed at a constant temperature. By adjusting this hygroscopic expansion coefficient, it is possible to prevent frame-like transmittance increase, that is, light leakage due to distortion, while maintaining the optical compensation function of the optical compensation sheet.

  The method for measuring the hygroscopic expansion coefficient is shown below. A sample having a width of 5 mm and a length of 20 mm was cut out from the produced cellulose ester film, and one end was fixed and hung in an atmosphere of 25 ° C. and 20% RH (R0). A weight of 0.5 g was hung from the other end and left for 10 minutes to measure the length (L0). Next, the length (L1) was measured while maintaining the temperature at 25 ° C. and the humidity at 80% RH (R1). The hygroscopic expansion coefficient was calculated by the following equation. The measurement was performed 10 samples for the same sample, and the average value was adopted.

Hygroscopic expansion coefficient [/% RH] = {(L1-L0) / L0} / (R1-R0)
In order to reduce the dimensional change due to moisture absorption of the produced cellulose ester film, it is preferable to add a compound having a hydrophobic group or fine particles. As the compound having a hydrophobic group, a material corresponding to a plasticizer or a degradation inhibitor having a hydrophobic group such as an aliphatic group or an aromatic group in the molecule is particularly preferably used. The amount of these compounds added is preferably in the range of 0.01 to 10% by mass with respect to the solution (dope) to be adjusted. In addition, the free volume in the cellulose ester film may be reduced. Specifically, the smaller the amount of residual solvent during film formation by the solvent casting method described later, the lower the free deposition. It is preferable to dry under the condition that the residual solvent amount with respect to the cellulose ester film is in the range of 0.01 to 1.00% by mass.

[Method for producing transparent support]
In this invention, it is preferable to manufacture a cellulose acetate film by a solvent cast method, and a film is manufactured using the solution (dope) which melt | dissolved the cellulose acetate in the organic solvent.

  Examples of the organic solvent to be used include conventionally known organic solvents. For example, those having a solubility parameter in the range of 17 to 22 are preferable. Lower aliphatic hydrocarbon chloride, lower aliphatic alcohol, ketone having 3 to 12 carbon atoms, ester having 3 to 12 carbon atoms, ether having 3 to 12 carbon atoms, fat having 5 to 8 carbon atoms Group hydrocarbons and aromatic hydrocarbons having 6 to 12 carbon atoms.

  The ether, ketone and ester may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.

  Specifically, for example, detailed compounds can be mentioned on pages 12 to 16 of the aforementioned public technical number 2001-1745.

  In particular, in the present invention, the solvent is preferably used by mixing two or more kinds of organic solvents, and particularly preferable organic solvents are three or more kinds of mixed solvents different from each other, and the first solvent has the number of carbon atoms. A ketone having 3 to 4 carbon atoms and an ester having 3 to 4 carbon atoms or a mixture thereof, and the second solvent is selected from ketones having 5 to 7 carbon atoms or acetoacetic acid ester; It is preferably selected from alcohol having a boiling point of 30 to 170 ° C. or hydrocarbon having a boiling point of 30 to 170 ° C. In particular, it is preferable from the viewpoint of the solubility of cellulose acetate to use 20 to 90 mass% of acetate ester, 5 to 60 mass% of ketones, and 5 to 30 mass% of alcohols.

  Further, non-halogen organic solvent systems that do not contain halogenated hydrocarbons are particularly preferred. Technically, halogenated hydrocarbons such as methylene chloride can be used without problems, but from the viewpoint of the global environment and working environment, it is preferable that the organic solvent is substantially free of halogenated hydrocarbons. “Substantially free” means that the proportion of halogenated hydrocarbon in the organic solvent is less than 5% by mass (preferably less than 2% by mass). Further, it is preferable that no halogenated hydrocarbon such as methylene chloride is detected from the produced cellulose acetate film.

  Specific examples of the organic solvent used in the present invention include paragraph numbers [0021] to [0025] in JP-A No. 2002-146043 and paragraph numbers [0016] to [0021] in JP-A No. 2002-146045. ] Examples of the solvent system described in the above.

  In addition to the organic solvent of the present invention, the dope used in the present invention may contain fluoroalcohol or methylene chloride in an amount of 10% by mass or less, more preferably 5% by mass or less of the total organic solvent amount of the present invention. It is preferable for improving the property and speeding up the solubility. The fluoroalcohol has a boiling point of 165 ° C or lower, preferably 111 ° C or lower, and more preferably 80 ° C or lower. The fluoroalcohol has about 2 to 10 carbon atoms, preferably about 2 to 8 carbon atoms. The fluoroalcohol is a fluorine atom-containing aliphatic alcohol, which may or may not have a substituent. As the substituent, an aliphatic substituent or an aromatic substituent containing or not containing a fluorine atom is preferable.

  Examples of the fluoroalcohol include compounds described in paragraph No. [0020] in JP-A-8-143709, paragraph No. [0037] in JP-A-11-60807, and the like. These fluoroalcohols may be used alone or in combination.

  When preparing the cellulose acetate solution of the present invention, the container may be filled with an inert gas such as nitrogen gas. The viscosity of the cellulose triacetate solution immediately before film formation may be within a range that allows casting, and is usually adjusted to a range of 10 ps · s to 2000 ps · s, particularly 30 ps · s to 400 ps. -S is preferable.

  Regarding the preparation of the cellulose acetate solution (dope) according to the present invention, the dissolution method is not particularly limited, and may be a room temperature dissolution method, a cooling dissolution method or a high temperature dissolution method, or a combination thereof. Regarding these, for example, JP-A-5-163301, JP-A-61-106628, JP-A-58-127737, JP-A-9-95544, JP-A-10-95854, JP-A-10-45950, JP-A-2000-53784, Kaihei 11-322946, JP-A-11-322947, JP-A-2-276830, JP-A-2000-273239, JP-A-11-71463, JP-A-04-259511, JP-A-2000-273184, JP-A-11-323017, JP-A-11-323017 11-302388 etc. and the preparation method of the cellulose acylate solution is mentioned. The above-described method for dissolving cellulose acylate in an organic solvent is applicable to the present invention as long as it is within the scope of the present invention. Further, the dope solution of cellulose acetate is usually subjected to concentration and filtration of the solution, and is also described in detail on page 25 of the aforementioned technical number 2001-1745. In addition, when it melt | dissolves at high temperature, it is the case where it is more than the boiling point of the organic solvent to be used, and in that case, it uses in a pressurized state.

  Next, in the present invention, a method for producing a film using a cellulose acylate solution will be described. As a method and equipment for producing a cellulose acylate film, a conventionally known solution casting film forming method and solution casting film forming apparatus called a drum method or a band method used for producing a cellulose triacetate film are used. The film forming process will be described by taking the band method as an example. The dope (cellulose acylate solution) prepared from the dissolving machine (kettle) is temporarily stored in a storage kettle, and the bubbles contained in the dope are defoamed to finish. Prepare. The prepared dope is sent from the dope discharge port to the pressure die through a pressure metering gear pump that can deliver the metered liquid with high accuracy by the number of rotations, and the dope is run endlessly from the die (slit) of the pressure die. The dope film (also referred to as a web) is peeled off from the metal support at the peeling point where the metal support is almost cast around the metal support. Both ends of the obtained web are sandwiched between clips, transported by a tenter while keeping the width, dried, then transported by a roll group of a drying device, dried, and wound up to a predetermined length by a winder. The combination of the tenter and the roll group dryer varies depending on the purpose. Each of these manufacturing steps (casting (including co-casting), metal support, drying, peeling, stretching, etc.) is described in detail on pages 25 to 30 of the aforementioned technical number 2001-1745. The contents made are mentioned. In the casting step, one type of cellulose acylate solution may be cast as a single layer, or two or more types of cellulose acylate solutions may be cast simultaneously and / or sequentially.

  Further, the cellulose acetate solution of the present invention can be cast simultaneously with other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing layer).

  In the conventional monolayer liquid, it is necessary to extrude a cellulose acetate solution having a high concentration and a high viscosity in order to obtain a necessary film thickness. In many cases, the problem occurs, such as a failure or flatness. As a solution to this, by casting a plurality of cellulose acetate solutions from the casting port, a highly viscous solution can be simultaneously extruded onto the support, and the planarity is improved and an excellent planar film can be produced. In addition, by using a concentrated cellulose acetate solution, it is possible to reduce the drying load and increase the production speed of the film.

[Method of imparting adhesion to transparent support]
When the alignment support is provided by the coating method, the transparent support of the present invention provides adhesion to the surface of the transparent support and is subjected to a surface treatment so that the alignment film coating solution is uniformly applied. Is preferred. Examples of the surface treatment method include a method of providing an undercoat layer of the alignment film. Adheres well to a polymer film as a first layer of a single-layer method in which only a single layer of a resin layer such as an undercoat layer described in JP-A-7-333433 or a resin layer containing both a hydrophobic group and a hydrophilic group is applied. A so-called multilayer in which a layer (hereinafter abbreviated as the first undercoat) is provided and a hydrophilic resin layer such as gelatin (hereinafter abbreviated as the undercoat second layer) is applied thereon as the second layer. The contents of the law (for example, described in JP-A-11-248940) can be mentioned. Examples of other surface treatment include a method of modifying the film surface by corona discharge treatment, glow discharge treatment, ultraviolet irradiation treatment, flame treatment, ozone treatment, acid treatment, alkali treatment, and the like. Details of these are described in detail on pages 30 to 32 of the aforementioned public technical number 2001-1745. Among these, alkali saponification treatment is particularly preferable, and it is extremely effective as the surface treatment of the cellulose acetate film.

[Alkaline saponification]
The alkali saponification treatment is performed by immersing, spraying or coating an alkali solution on a transparent support. Preferably, a saponification treatment is preferably performed by coating, and examples of the coating method include a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, and an E-type coating method.

[Alkaline solution]
The alkaline solution of the present invention is preferably an alkaline solution having a pH of 11 or more. More preferably, the pH is 12-14. Examples of the alkaline agent used in the alkaline solution include inorganic alkaline agents such as sodium hydroxide, potassium and lithium, diethanolamine, triethanolamine, DBU (1,8-diazabicyclo [5,4,0] -7. -Undecene), DBN (1,5-diazabicyclo [4,3,0] -5-nonene), tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, triethylbutylammonium Organic alkali agents such as hydroxide are also used. These alkali agents can be used alone or in combination of two or more, and a part of them may be added, for example, in the form of a halogenated salt. Among these alkali agents, sodium hydroxide or potassium hydroxide is preferable because the pH can be adjusted in a wide pH range by adjusting these amounts.

  The concentration of the alkaline solution is determined according to the type of alkaline agent used, the reaction temperature, and the reaction time. The content of the alkaline agent is preferably 0.1 to 5 mol / Kg in the alkaline solution, 0.5 ˜3 mol / Kg is more preferred.

The alkaline solution solvent of the present invention preferably comprises a mixed solution of water and a water-soluble organic solvent. As the organic solvent, any organic solvent miscible with water can be used, but those having a boiling point of 120 ° C. or lower, more preferably 100 ° C. or lower are preferable.
Among them, preferred organic solvents are those having an inorganic / organic value (I / O value) of 0.5 or more and a solubility parameter in the range of 16 to 40 [mJ / m ³ ] ^1/2 . More preferably, the I / O value is 0.6 to 10 and the solubility parameter is 18 to 31 [mJ / m ³ ] ^1/2 . If the I / O value is more inorganic than this range or the solubility parameter is low, the alkali saponification rate decreases, and the overall uniformity of the saponification degree becomes unsatisfactory. On the other hand, when the I / O value is on the organic side of the above range or the solubility parameter is highly soluble, the saponification rate is fast, but haze is likely to occur. Dissatisfied. In addition, when an organic solvent, particularly an organic solvent in each of the above organic and soluble ranges, is used in combination with a surfactant, a compatibilizing agent, etc. described later, a high saponification rate is maintained and the saponification degree is uniform over the entire surface. Improves.

  Examples of the organic solvent having preferable characteristic values include those described in “Synthetic Organic Chemistry Association”, “New Edition Solvent Pocket Book” (Ohm Co., Ltd., published in 1994) and the like. (In addition, the inorganic / organic value (I / O value) of the organic solvent is described in, for example, Yoshio Tanaka, Organic Conceptual Diagram) Sankyo Publishing Co., Ltd., 1983, pages 1-31).

  Specifically, monohydric aliphatic alcohols (eg, methanol, ethanol, propanol, butanol, pentanol, hexanol, etc.), alicyclic alkanols (eg, cyclohexanol, methylcyclohexanol, methoxycyclohexanol, cyclohexylmethanol, Cyclohexylethanol, cyclohexylpropanol, etc.), phenylalkanols (eg, benzyl alcohol, phenylethanol, phenylpropanol, phenoxyethanol, methoxybenzyl alcohol, benzyloxyethanol, etc.), heterocyclic alkanols (furfuryl alcohol, tetrahydrofurfuryl alcohol) Etc.), monoethers of glycol compounds (methyl cellosolve, ethyl cellosolve, propyl cellosolve, methoxymethoxyethane) Butyl cell sorb, hexyl cell sorb, methyl carbitol, ethyl carbitol, propyl carbitol, butyl carbitol, methoxy triglycol, ethoxy triglycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl Ethers, etc.) ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), amides (eg, N, N-dimethylformamide, dimethylformamide, N-methyl-2-pyrrolidone, 1,3 dimethylimidazolidinone, etc.) , Sulfoxides (eg, dimethyl sulfoxide) and ethers (eg, tetrahydrofuran, pyran, dioxane, trioxane, dimethylcellosolve, diethylcellosolve, dipro Ruserusorubu, methyl ethyl cellosolve, dimethyl carbitol, dimethyl carbitol, methyl ethyl carbitol, etc.) and the like. The organic solvent to be used may be used alone or in combination of two or more.

  When at least one organic solvent is used alone or in combination of two or more organic solvents, those having high solubility in water are preferable. The solubility of water in the organic solvent is preferably 50% by mass or more, and more preferably freely mixed with water. This makes it possible to prepare an alkaline solution having sufficient solubility in an alkali agent, a salt of a fatty acid by-produced by a saponification treatment, a carbonate salt generated by absorbing carbon dioxide in the air, and the like. The use ratio of the organic solvent in the solvent is determined according to the type of solvent, miscibility with water (solubility), reaction temperature and reaction time. The mixing ratio of water and organic solvent is preferably 3/97 to 85/15 mass ratio. More preferably, it is 5 / 95-60 / 40 mass ratio, More preferably, it is 15 / 85-40 / 60 mass ratio. In this range, the entire film surface can be easily saponified uniformly without impairing the optical properties of the acylate film.

  As the organic solvent contained in the alkaline solution used in the present invention, an organic solvent (for example, fluorinated alcohol) different from the organic solvent having the above-mentioned preferable I / O value is used as a dissolution aid for the surfactant and compatibilizer described later. You may use together as an agent. The content is preferably 0.1 to 5% with respect to the total weight of the liquid used.

  The alkaline solution used in the present invention preferably contains a surfactant. By adding a surfactant, the surface tension can be lowered to facilitate coating, and the uniformity of the coating film can be increased to prevent cissing failure, and haze that tends to occur in the presence of an organic solvent is suppressed. Progress evenly. The effect becomes particularly remarkable by the coexistence of a compatibilizer described later. There is no restriction | limiting in particular in surfactant to be used, Any of anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, a fluorine-type surfactant, etc. may be sufficient.

  Specifically, for example, Tokiyuki Yoshida “Surfactant Handbook (new edition)” (Engineering Books, published in 1987), “Functional Creation / Material Development / Applied Technology of Surfactant”, Volume 1 (Technical Education Publishing) , Published in 2000) and the like. Among these surfactants, quaternary ammonium salts as cationic surfactants, various polyalkylene glycol derivatives as nonionic surfactants, polyethylene oxide derivatives such as various polyethylene oxide adducts, Betaine-type compounds as amphoteric surfactants are preferred. In the alkaline solution, it is also preferable to use a nonionic activator and an anionic activator or a nonionic activator and a cationic activator together in order to enhance the effect of the present invention.

  The amount of these surfactants added to the alkaline solution is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass.

  The alkaline solution used in the present invention preferably contains a compatibilizing agent. In the present invention, the “compatibilizer” refers to a hydrophilic compound having a water solubility of 50 g or more with respect to 100 g of the compatibilizer at a temperature of 25 ° C. The solubility of the water of the compatibilizing agent is preferably 80 g or more, more preferably 100 g or more with respect to 100 g of the compatibilizing agent. When the compatibilizer is a liquid compound, the boiling point is preferably 100 ° C. or higher, and more preferably 120 ° C. or higher.

  The compatibilizing agent has an action of preventing drying of the alkaline solution attached to a wall surface such as a bath for storing the alkaline solution, suppressing fixation, and stably holding the alkaline solution. Also, after applying the alkali solution to the surface of the transparent support and holding it for a certain period of time, until the saponification treatment is stopped, the applied alkali solution thin film is dried, causing precipitation of solids, and the water washing step It has the effect of preventing difficulty in washing out the solid matter in Furthermore, phase separation between water as a solvent and the organic solvent is prevented. In particular, the coexistence of the surfactant, the organic solvent, and the compatibilizer described above allows the treated transparent support to have a low haze and be stable and uniform even in the case of a long continuous saponification treatment. The degree of saponification.

  The compatibilizing agent is not particularly limited as long as it is a material that satisfies the above conditions. For example, a water-soluble polymer containing a repeating unit having a hydroxyl group and / or an amide group, such as a polyol compound or a saccharide, can be preferably mentioned. . As the polyol compound, any of a low molecular compound, an oligomer compound, and a high molecular compound can be used. Examples of aliphatic polyols include alkanediols having 2 to 8 carbon atoms (for example, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, glycerol monomethyl ether, glycerol monoethyl ether, cyclohexanediol, cyclohexanedimethanol). , Diethylene glycol, dipropylene glycol, etc.), C3-C18 alkanes containing 3 or more hydroxyl groups (for example, glycerin, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, diglycerin) , Dipentaerythritol, inositol, etc.). As the polyalkyleneoxy polyols, the same alkylene diols as described above may be bonded to each other, or different alkylene diols may be bonded to each other, but a polyalkylene polyol in which the same alkylene diols are bonded to each other is more preferable. . In any case, the number of bonds is preferably 3 to 100, more preferably 3 to 50. Specific examples include polyethylene glycol, polypropylene glycol, and poly (oxyethylene-oxypropylene).

  Examples of saccharides include “Natural Polymers” Chapter 2 (Kyoritsu Shuppan Co., Ltd., published in 1984) edited by the Society of Polymer Science, Japan, “Modern Industrial Chemistry 22, Natural Products Industrial Chemistry”. II "(Asakura Shoten Co., Ltd., published in 1967) and the like. Among them, saccharides that do not have a free aldehyde group and a ketone group and do not exhibit reducibility are preferable. Saccharides are generally classified into glucose, sucrose, trehalose type oligosaccharides in which reducing groups are bonded to each other, glycosides in which a reducing group of saccharides and non-saccharides are combined, and sugar alcohols reduced by hydrogenation of saccharides. Both are suitably used in the present invention. For example, saccharose, trehalose, alkyl glycoside, phenol glycoside, mustard oil glycoside, D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit , D, L-Tallit, Zulsicit, Allozulcit, and reduced water candy. These saccharides can be used alone or in combination of two or more.

  Examples of the water-soluble polymer having a repeating unit having a hydroxyl group and / or an amide group include natural gums (for example, gum arabic, guar gum, tragand gum, etc.), polyvinylpyrrolidone, dihydroxypropyl acrylate polymer, celluloses. Or the addition reaction body of chitosans and an epoxy compound (ethylene oxide or propylene oxide) is mentioned. Of these, polyol compounds such as alkylene polyols, polyalkyleneoxy polyols and sugar alcohols are preferred.

  The content of the compatibilizer is preferably 0.5 to 25% by mass and more preferably 1 to 20% by mass with respect to the alkaline solution.

  The alkaline solution used in the present invention can contain other additives. Examples of other additives include known additives such as antifoaming agents, alkaline solution stabilizers, pH buffering agents, preservatives, and antibacterial agents.

[Alkaline saponification method]
The surface treatment method of the cellulose acetate film using the above alkaline solution may be any conventionally known method, but the coating method is preferred particularly when only one surface of the film is uniformly saponified without unevenness. As a coating method, a conventionally known coating method [for example, die coater (extrusion coater, slide coater), roll coater (forward roll coater, reverse roll coater, gravure coater), rod coater, blade coater, etc.] is preferable. Available. The saponification treatment is preferably performed at a treatment temperature in a range not exceeding 120 ° C. at which deformation of the film to be treated, alteration of the treatment liquid, and the like do not occur. Further, the temperature is preferably 10 ° C. or higher and 100 ° C. or lower. In particular, a temperature of 20 to 80 degrees is preferable.
The time for the saponification treatment is determined by appropriately adjusting the alkali solution and the treatment temperature, but it is preferably performed in the range of 1 second to 60 seconds.

  Further, the step of saponifying the cellulose acetate film with an alkaline solution at a temperature of at least 10 ° C. on the surface, the step of maintaining the temperature of the cellulose acetate film at least at 10 ° C., and the alkali solution from the cellulose acetate film It is preferable to carry out an alkali saponification treatment by a washing step. The saponification treatment in which the surface of the cellulose acetate film is performed with an alkaline solution at a predetermined temperature includes a step of adjusting the temperature to a predetermined temperature before coating, a step of adjusting the alkaline liquid to a predetermined temperature in advance, or The combined process etc. are mentioned. It is preferable to combine with a step of adjusting to a predetermined temperature before application. After the saponification reaction, it is preferable to wash and remove the alkali solution and the saponification reaction product from the film surface by washing with water, neutralizing and washing with water. Specifically, for example, the contents described in International Publication No. 02/46809 pamphlet and the like can be mentioned.

  A preferable adhesion imparting process will be described with reference to FIG. The adhesion imparting treatment, which is a saponification treatment of the transparent support included in the saponification treatment of the optical compensation film of the present invention, includes: (a) applying an aqueous alkali solution containing at least water, an organic solvent and an alkali agent to the transparent support. And (b) a saponification treatment step in which the transparent support is saponified with the alkaline aqueous solution, and the amount of the plasticizer on the surface of the saponification treatment surface of the transparent support is 0.25 or less as measured by the ATR / IR method. And a processing method including:

  As shown to Fig.1 (a), the alkaline aqueous solution 12 is apply | coated to the cellulose-ester film 10 which is a transparent support body. A plasticizer 14 is added to the cellulose ester film 10 in order to improve mechanical properties or improve the drying speed. As the plasticizer 14, a hydrophobic phosphoric acid ester or a carboxylic acid ester is used.

  Next, as shown in FIG. 1 (b), the surface of the cellulose ester film 10 is saponified with the alkaline aqueous solution 12. The film surface temperature of the cellulose ester film 10 is controlled to a predetermined temperature by a heater (not shown). During the saponification treatment, the plasticizer 14 in the cellulose ester film 10 is extracted on the surface by the organic solvent in the alkaline aqueous solution 12. On the other hand, the plasticizer 14 is also present in the cellulose ester film 10. The inventors reextracted the plasticizer 14 in the cellulose ester film 10 in a step described later, and the plasticizer 14 inhibits the crosslinkability of the polyfunctional monomer compound containing a polymerizable group, in particular, the cellulose ester film 10. It has been found that the plasticizer 14 present on the surface of the resin affects the crosslinkability. Therefore, it is important to extract as much plasticizer 14 as possible from the surface of the cellulose ester film 10 during the saponification treatment.

  Next, as shown in FIG. 1 (c), the alkaline aqueous solution used for the saponification treatment and the extracted plasticizer are applied from the saponified cellulose ester film 10 ′ by a method of applying washing water or a method of spraying washing water. Washed and removed. This is because the saponification reaction proceeds when the alkaline aqueous solution remains.

  In the present invention, the cellulose ester film 10 is saponified in the saponification treatment step so that the amount of the plasticizer on the saponification treated surface layer of the saponified cellulose ester film 10 ′ after the washing step is 0.25 or less as measured by the ATR / IR method. It is processed. By setting the amount of the plasticizer 14 on the treated surface of the saponified cellulose ester film 10 ′ within the above range, it is possible to suppress the phenomenon of inhibiting the crosslinkability of the polyfunctional monomer compound containing a polymerizable group.

  Next, as shown in FIG. 1D, an alignment film forming material 16 such as polyvinyl alcohol or modified polyvinyl alcohol is applied onto the saponified cellulose ester film 10 '. At this time, since the plasticizer 14 on the treated surface of the saponified cellulose ester film 10 ′ is small, the amount of the plasticizer 14 extracted from the saponified cellulose ester film 10 ′ when applying the alignment film forming material 16 is small.

  Next, as shown in FIG. 1E, the alignment film forming material 16 is crosslinked by heating and drying the alignment film forming material 16 on the saponified cellulose ester film 10 '. Since the amount of the plasticizer 14 contained in the alignment film forming material 16 is small, the alignment film forming material 16 becomes the alignment film 18 without being blocked by the crosslinking of the alignment film forming material 16.

  Finally, as shown in FIG. 1 (f), a liquid crystal layer forming material is applied on the alignment film 18, the solvent is evaporated in a heating zone (not shown), and the liquid crystal layer 20 is formed on the alignment film 18. Further, the liquid crystal layer 20 is irradiated with ultraviolet rays by an ultraviolet (UV) lamp. When the solvent is evaporated in the heating zone, the hardening reaction of the liquid crystal layer 20 is promoted. Since the amount of the cross-linking agent 14 in the alignment film 18 is small, steric hindrance is reduced and the film strength is improved even when ultraviolet rays are irradiated by an ultraviolet (UV) lamp. If the amount of re-extraction of the plasticizer is large in the step of FIG. 1 (e), this crosslinking is inhibited.

  As described above, when a large amount of plasticizer is extracted from the cellulose ester film during the saponification treatment, and the amount of the plasticizer on the treated surface is 0.25 or less as measured by the ATR / IR method, the crosslinkability is inhibited. Can be suppressed. In addition, it is understood that the coating film formed on the saponified cellulose ester film is not limited to the alignment film forming material, and may be any polyfunctional monomer compound containing a polymerizable group.

[Alignment film]
The alignment film of the present invention is preferably an alignment film formed by applying an organic compound (preferably polymer) coating solution. A cured polymer film is preferred from the viewpoint of the strength of the alignment film itself and the adhesion to the optically anisotropic layer as the lower layer or the upper layer. The alignment film is provided in order to define the alignment direction of the liquid crystal compound provided thereon. Examples of the orientation regulating method include conventionally known rubbing, application of a magnetic field or electric field, and light irradiation.

  The alignment film used in the present invention can correspond to the type of display mode of the liquid crystal cell. In display modes (eg, VA, OCB, HAN) in which many rod-like liquid crystal molecules in the liquid crystal cell are aligned substantially vertically, the liquid crystal molecules in the optically anisotropic layer are aligned substantially horizontally. It has a function to make it. In a display mode in which many rod-like liquid crystal molecules in the liquid crystal cell are aligned substantially horizontally (eg, STN), the liquid crystal molecules of the optically anisotropic layer have a function of being substantially vertically aligned. . In a display mode in which many rod-like liquid crystalline molecules in the liquid crystal cell are substantially obliquely aligned (eg, TN), the liquid crystalline molecules of the optically anisotropic layer have a function of substantially obliquely aligning. .

  Specific types of polymers used in the alignment film of the present invention are described in the literature on optical compensation sheets using discotic liquid crystalline molecules corresponding to the various display modes described above. As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of the polymer include compounds described in paragraph [0022] of JP-A-8-338913. Preferable examples include water-soluble polymers (for example, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol). Among these, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferable, and polyvinyl alcohol and modified polyvinyl alcohol. Polyvinyl alcohol is most preferred.

  The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%, and most preferably 85 to 95%. The degree of polymerization of polyvinyl alcohol is preferably 100 to 3000.

  The modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. Specific examples of these modified polyvinyl alcohol compounds include, for example, paragraph number [0074] in JP-A 2000-56310, paragraph numbers [0022] to [0145] in JP-A 2000-155216, Examples described in paragraphs [0018] to [022] in the specification of JP-A-2002-62426 are included.

  When the alignment is performed by light irradiation, a photo-alignment group that exhibits a photo-alignment function is included in the molecule. Examples of these photo-alignment groups include those described in “Liquid Crystal, Vol. 3 (1) 3-16 (1999)” written by Masaki Hasegawa, and have a photo-alignment function by a photodimerization reaction having a C═C bond. Photo-alignment group (for example, polyene group, stilbene group, stilbazole group, stilbazolium group, cinnamoyl group, hemithioindigo group, chalcone group, etc.), photo-alignment function that exhibits photo-alignment function by photodimerization reaction with C = O bond Group (for example, a group having a structure such as a benzophenone group or a coumarin group). Specific examples include those described in paragraphs [0021] of JP-A Nos. 2000-122069 and 2002-317013.

  Examples of cross-linking agents for polymers (preferably water-soluble polymers, more preferably polyvinyl alcohol or modified polyvinyl alcohol) used in the alignment film include aldehydes, N-methylol compounds, dioxane derivatives, and carboxyl groups by activating them. Compounds that act, active vinyl compounds, active halogen compounds, isoxazoles and dialdehyde starches are included. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  The addition amount of the crosslinking agent is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass with respect to the polymer. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. If the crosslinking agent remains in the alignment film in an amount exceeding 1.0% by mass, sufficient durability cannot be obtained. When such an alignment film is used in a liquid crystal display device, reticulation may occur when used for a long time or when left in a high temperature and high humidity atmosphere for a long time.

[Carboxylic acid compound contained in alignment film]
The alignment film composition of the present invention preferably contains an organic carboxylic acid compound having at least one polar group. As a result, the coated surface of the optical compensation sheet obtained by applying an optically anisotropic layer after aligning the obtained alignment film by an aligning means is good and reduces or eliminates optical defects such as white spots. The improvement effect is expressed. The reason is presumed that the organic carboxylic acid compound having at least one polar group contained in the alignment film is aligned with the liquid crystal molecules when the surface of the alignment film is stabilized and the optical anisotropic layer is applied. One factor seems to be to reduce the impact on the condition. Naturally, the effect varies depending on the amount added, so the timely amount needs to be adjusted.

Examples of the organic carboxylic acid compound having at least one polar group include carboxylic acids containing at least one polar group containing hydrogen atoms and having a hydrogen bond. These carboxylic acids may be any of aliphatic compounds, aromatic compounds, or heterocyclic compounds. Specific polar groups include —OH, —SH, —NHR, —CONHR, —SO ₂ NHR, —HNCONHR, —NHSO ₂ NHR, —NHCOR ¹ , —NHSO ₂ R ¹ . However, R represents a hydrogen atom, an aliphatic group, an aryl group, or a heterocyclic group. R ¹ represents an aliphatic group, an aryl group, or a heterocyclic group. When the carboxylic acid contains a plurality of the above polar groups, the polar groups may be the same or different.

Preferred specific polar groups of the present invention include —OH, —SH, —NHR, —CONH ₂ , —SO ₂ NH ₂ , —HNCONHR, —NHSO ₂ NHR, —NHSO ₂ R ¹ . Here, R represents a hydrogen atom, an aliphatic group, an aryl group, or a heterocyclic group. R ¹ represents an aliphatic group, an aryl group, or a heterocyclic group.

  When R represents an aliphatic group, the aliphatic group is a linear or branched alkyl group having 1 to 22 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group). Group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nanodecyl group, eicosanyl group, heneicosanyl group, docosanyl group, etc.), carbon A linear or branched alkenyl group having 2 to 22 (for example, vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, octenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, hexadecenyl group, octadecenyl group, Eicosenyl group, dococenyl group, butadienyl group, pentadie Group, hexadienyl group, octadienyl group, etc.) linear or branched alkynyl group having 2 to 22 carbon atoms (for example, ethynyl group, propynyl group, butynyl group, hexynyl group, octanyl group, decanyl group, dodecanyl group, etc.) ), An alicyclic hydrocarbon group having 5 to 22 carbon atoms (for example, cyclopentane, cyclopentene, cyclopentadiene, cyclohexane, cyclohexene, cyclohexadiene, cycloheptane, cycloheptene, cycloheptadiene, cyclooctane, cyclooctene, cyclooctadiene , Decalin, etc.). Among these, a linear aliphatic group having 1 to 18 carbon atoms and a branched aliphatic group having 3 to 18 carbon atoms are more preferable. The aryl group represents an aryl group having 6 to 18 carbon atoms (as the aryl ring, benzene, naphthalene, dihydronaphthalene, biphenylene, etc.). As the heterocyclic group, a heterocyclic group having a monocyclic or polycyclic ring structure containing at least one of an oxygen atom, a sulfur atom, and a nitrogen atom (for example, a furanyl group, Tetrahydrofuranyl group, pyranyl group, pyroyl group, pyridiyl group, pyrazinyl group, morpholinyl group, thienyl group, benzothienyl group, etc.).

The above aliphatic group, aryl group, and heterocyclic group may each have a substituent, and as the substituent that can be introduced, a monovalent nonmetallic atomic group excluding hydrogen is used. Specific examples of the nonmetallic atom group include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), a cyano group, a nitro ^{group, -OR 11, -SR 11, -COR} 11, -COOR 11, —OCOR ¹¹ , —SO ₂ R ¹¹ , —NHCONHR ¹¹ , —N (R ¹² ) COR ¹¹ , —N (R ¹² ) SO ₂ R ¹¹ , —N (R ¹³ ) (R ¹⁴ ), —CON (R ¹³ ) (R ¹⁴ ), —SO ₂ N (R ¹³ ) (R ¹⁴ ), —P (═O) (R ¹⁵ ) (R ¹⁶ ), —OP (═O) (R ¹⁵ ) (R ¹⁶ ), — Si (R ¹⁷ ) (R ¹⁸ ) (R ¹⁹ ), an aliphatic group having 1 to 22 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a heterocyclic group. These aliphatic group, aryl group and heterocyclic group have the same meanings as those for R.

R ¹¹ represents an aliphatic group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a heterocyclic group. The aliphatic group in R ¹¹ has the same meaning as the aliphatic group represented by R. Examples of the aryl group for R ¹¹ include the same aryl groups as those exemplified as the substituent that can be introduced into the aliphatic group represented by R. Such an aryl group may further have a substituent, and examples of the substituent include the same groups as those exemplified as the substituent that can be introduced into the aliphatic group represented by R. R ¹² represents a hydrogen atom or the same as the R ¹¹ group. R ¹³ and R ¹⁴ each independently represents a hydrogen atom or the same as R ^11, and R ¹³ and R ¹⁴ are bonded to each other to form a 5-membered or 6-membered ring containing an N atom. It may be formed.

R ¹⁵ and R ¹⁶ each independently represents an aliphatic group having 1 to 22 carbon atoms, an aryl group having 6 to 14 carbon atoms, or —OR ¹¹ . The aliphatic group in R ¹⁵ and R ¹⁶ has the same meaning as the aliphatic group represented by R. Examples of the aryl group in R ¹⁵ and R ¹⁶ include the same aryl groups as those exemplified as the substituent that can be introduced into the aliphatic group represented by R. Such an aryl group may further have a substituent, and examples of the substituent include those exemplified as the substituent that can be introduced into the aliphatic group represented by R. However, in such a polar substituent, both R ¹⁵ and R ¹⁶ are not represented by —OH.

R ¹⁷ , R ¹⁸ and R ¹⁹ each independently represent a hydrocarbon group having 1 to 22 carbon atoms or —OR ^20, and at least one of these substituents represents a hydrocarbon group. The hydrocarbon group represents the same aliphatic group and aryl group represented by R, and —OR ²⁰ represents the same contents as —OR ¹¹ . The aliphatic group, aryl group and heterocyclic group in R ¹ are the same as R. Examples of the organic carboxylic acid compound having at least one polar group of the present invention include aliphatic carboxylic acids having 1 to 22 carbon atoms (excluding carbon atoms of carboxylic acids), aromatic carboxylic acids having 6 to 14 carbon atoms, and heterocyclic rings. A carboxylic acid compound of a carboxylic acid having a pKa of 6.5 or less is particularly preferable. More preferably, the carboxylic acid has a pKa of 3.0 to 6.5.

  Specific examples of the organic carboxylic acid compound having at least one polar group include, for example, oxyacids (for example, glycolic acid, lactic acid, glyceric acid, and α-oxyalkanoic acid (alkanes having 3 to 18 carbon atoms). , Etc.), amino acids, α-oxy-β-amino acids, α-oxy-γ-amino acids, β-oxy-α-amino acids, compounds in which the hydroxyl group of these oxyacids or oxyamino acids is derived from alkoxy groups, hydrides At least one hydroxyl group of xylcyclohexanecarboxylic acid, hydroxybenzenecarboxylic acid, polyol (for example, alkanediol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, cyclohexanediol, etc.) is converted into a cyclic carboxylic acid anhydride (succinic acid). , Maleic acid, Compounds esterified with taric acid, adipic acid, cyclohexanedicarboxylic acid, anhydrides such as phthalic acid, etc.), polyamino compounds (eg, alkylenediamine, diethylenetriamine, triethylenetetramine, cyclohexanediamine, phenylenediamine, etc.) and cyclic carboxylic acid anhydrides The compound derived from the compound amidated with a product is exemplified, but the compound of the present invention is not limited thereto.

  More preferred is a carboxylic acid compound which is a polycarboxylic acid containing at least one hydroxyl group and in which at least one carboxyl group is esterified. Examples of the polycarboxylic acid containing at least one hydroxyl group include tartronic acid, malic acid, tartaric acid, citric acid, oxyglutamic acid (β-form, γ-form), and at least two hydroxyl groups of the above-mentioned polyol. Examples thereof include compounds esterified with an acid anhydride.

  At least one carboxylic acid of these polycarboxylic acid compounds is preferably ester-substituted with a hydrocarbon group having 1 to 22 carbon atoms. Specific examples of the C1-C18 hydrocarbon group to be ester-substituted are the same as the aliphatic group, aromatic group, and heterocyclic group described in R above. These hydrocarbon groups may be substituted, and examples of the substituent include those having the same contents when substituted with R.

  The organic carboxylic acid compound having at least one polar group of the present invention is preferably added at a ratio of 0.01 to 1.0% by mass in the alignment film composition. Furthermore, 0.02-0.5 mass% is preferable. In this range, an optical compensation sheet free from optical defects such as white spots in which the film strength is sufficiently maintained can be obtained. Furthermore, even if a long film is continuously manufactured, it can be manufactured with extremely stable performance.

  The alignment film is basically formed by applying a coating solution containing the polymer, a crosslinking agent and an organic carboxylic acid compound having at least one polar group, which is a composition for forming an alignment film, onto a transparent support and then drying by heating. It is a cured film that can be formed by (crosslinking) and orientation treatment. As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming composition, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an orientation film and also an optically anisotropic layer reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes.

  Further, when the coating liquid for the optically anisotropic layer is applied after the coating liquid containing the composition for forming an alignment film of the present invention is applied to a support, dried, and oriented by an orientation means, the orientation liquid is applied. It is preferable that the surface of the membrane be maintained in the range of pH 2.0 to 6.9. Furthermore, pH 2.5-5.0 is more preferable. Further, when applying the coating solution for the optically anisotropic layer, it is preferable that the fluctuation range ΔpH of the pH of the alignment film surface in the coating width direction is within a range of ± 0.30. More preferably, ΔpH is in the range of ± 0.15. In this range, an optical compensation sheet provided with an optically anisotropic layer is preferable because optical defects are remarkably reduced.

  The method for measuring the pH value of the alignment film surface is to leave the sample coated with the alignment film in an environment of (temperature 25 ° C./humidity 65% RH) for 1 day, and then place 10 ml of pure water in a nitrogen atmosphere. Immediately read the pH value with a pH meter. In order to specify the pH value of the alignment film surface of the present invention and to control the ΔpH in the coating width direction, it is achieved by coating by the above rod coating method. Furthermore, it is also effective to adjust the drying temperature of the film surface, the air volume when using the drying air, the wind direction, and the like.

  The alignment film is provided on the transparent support or the undercoat layer. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above. For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average. In the case of photo-alignment by light irradiation, the light source as the light irradiation device can be an ultra-high pressure mercury lamp, xenon lamp, fluorescent lamp, laser or the like. Are combined with a polarizing film (through the polarizing film) to convert the ultraviolet light into linearly polarized light and irradiate the photo-alignment film. As the polarizing film, stretch dyed PVA is mainly used. As this linearly polarized ultraviolet irradiation device, for example, the one disclosed in JP-A-10-90684 can be used. The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 1 μm.

[Optically anisotropic layer]
The optically anisotropic layer is formed from a liquid crystalline composition. The liquid crystal composition preferably used contains at least one kind of a liquid crystal compound and at least one kind of a predetermined fluoroaliphatic group-containing polymer.

-Fluoro aliphatic group containing polymer The aliphatic group containing polymer used for this invention is represented by following General formula (1).

In the general formula (1), i and j each represent an integer of 1 or more, meaning that each repeating unit includes i and j types, respectively; M is derived from an ethylenically unsaturated monomer, and k (k Is an integer greater than or equal to 1) types of repeating units; a, b and c are mass percentages representing a polymerization ratio, Σai represents a numerical value of 1 to 98% by mass, and Σbj represents a numerical value of 1 to 98% by mass. Σck represents a numerical value of 1 to 98% by mass; R ¹¹ and R ¹² each represent a hydrogen atom or a methyl group; X ¹ and X ² each represent an oxygen atom, a sulfur atom, or —N (R ¹³ ). R ¹³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; m1 and m2 each represent an integer of 1 to 6; and n1 represents an integer of 0 to 3.

In the above formula (1), the following repeating units A and B are respectively a fluoroaliphatic group-containing monomer A having a terminal of-(CF ₂ CF ₂ ) ₃ F and a terminal of-(CF ₂ CF ₂ ) ₂ F. It is a repeating unit derived from a fluoroaliphatic group-containing monomer B.

In the repeating units A and B, X ¹ and X ² are each preferably O. That is, each of the repeating units A and B is preferably a repeating unit derived from a (meth) acrylic monomer. m1 and m2 are each preferably 1 to 4, and more preferably 1 to 2. n1 is preferably 0 to 2, more preferably 0 or 1, and most preferably 0.

  Examples of the fluoroaliphatic group-containing monomer for deriving the repeating unit A are listed below, but are not limited thereto. Especially, exemplary compound A-1-6 and A-2-6 which are (meth) acrylic-type monomers are preferable. In addition, although the following exemplary compounds enumerate the compound of n1 = 0 in Formula (1), the compound of n1 is 1-3, of course, of the fluoro aliphatic group containing monomer which derives the said repeating unit A. Included in the example.

  Examples of the fluoroaliphatic group-containing monomer for deriving the repeating unit B are listed below, but are not limited thereto. Especially, exemplary compound B1-1-6 and B2-1-6 which are (meth) acrylic-type monomers are preferable.

  The fluoroaliphatic group-containing monomer can be produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). With respect to the production method of these fluoroaliphatic compounds, for example, “Synthesis and Function of Fluorine Compounds” (Supervision: Nobuo Ishikawa, published by CMC Corporation, 1987), “Chemistry of Organic Fluorine Compounds” II "(Monograph 187, Ed by Milos Hudlicky and Attila E. Pavlath, American Chemical Society 1995), pages 747-752. The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen (example in Scheme-1). showed that).

  The obtained terminal iodinated telomer is usually subjected to an appropriate terminal chemical modification such as [Scheme 2] and led to a fluoro fatty compound.

  In the formula (1), M is a repeating unit derived from an ethylenically unsaturated monomer. M is not particularly limited, but is preferably a repeating unit having a polar group having hydrogen bonding in the side chain. M is preferably a repeating unit represented by the following general formula (2).

In the general formula (2), R ¹ , R ² , and R ³ each independently represent a hydrogen atom, an alkyl group, a halogen atom, or a group represented by -LQ. L represents a divalent linking group, and Q represents a polar group having hydrogen bonding properties.

  L is preferably an arbitrary group selected from the following linking group group, or a divalent linking group formed by combining two or more thereof.

(Linked group group)
Single bond, —O—, —CO—, —NR ⁴ —, —S—, —SO ₂ —, —P (═O) (OR ⁵ ) —, alkylene group, arylene group (R ⁴ is hydrogen atom, alkyl A group, an aryl group, or an aralkyl group, and R ⁵ represents an alkyl group, an aryl group, or an aralkyl group.)
More specifically, in general formula (2), R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) ) Or a group represented by -LQ described later, preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, more preferably hydrogen. An atom and an alkyl group having 1 to 4 carbon atoms are preferable, and a hydrogen atom and an alkyl group having 1 to 2 carbon atoms are particularly preferable. Specific examples of the alkyl group that R ¹ , R ² and R ³ can take include a methyl group, an ethyl group, an n-propyl group, an n-butyl group and a sec-butyl group. The alkyl group may have one or more substituents. Examples of the substituent include a halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl Group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamido group, sulfolyl group, carboxyl group and the like.

  The carbon number of the alkyl group does not include the carbon atom of the substituent. The same applies to the carbon number of other groups.

L is a single bond, —O—, —CO—, —NR ⁴ —, —S—, —SO ₂ —, —PO (OR ⁵ —, an alkylene group, an arylene group, or a divalent group formed by a combination thereof. Wherein R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, R ⁵ represents an alkyl group, an aryl group, or an aralkyl group, L is a single bond, — ^{O -, - CO -, -} NR 4 -, - S -, - SO 2 -, an alkylene group, may contain an arylene group preferably, -CO -, - O -, - NR 4 -, an alkylene group or an arylene, In particular, it preferably contains an alkyleneoxy group containing both —O— and an alkylene group, and contains a polyalkyleneoxy group containing a repeating alkyleneoxy group. When L contains an alkylene group, the number of carbon atoms of the alkylene group is preferably 1 to 10, more preferably 1 to 8, particularly preferably 1 to 6. As specific examples of particularly preferred alkylene groups, , A methylene group, an ethylene group, a trimethylene group, a tetrabutylene group, a hexamethylene group, etc. The alkylene group (which also includes an alkylene group included in the alkyleneoxy group) may have a branched structure. The number of carbon atoms in the branched alkylene chain is preferably 1 to 3.

  When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and particularly preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene groups and naphthalene groups. When L contains a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and particularly preferably. 7-16. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group. The group listed as L may have an appropriate substituent. Examples of such a substituent include the same substituents as those described above as the substituents for R1 to R3. Although the specific structure of L is illustrated below, this invention is not limited to these specific examples.

However, in L-28, R ^{51 to} R ⁵⁸ are each a hydrogen atom or an alkali group (preferably having 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms), and n is 1 to 12 (preferably 2). An integer of 10 to 10. One of R ⁵³ and R ⁵⁴ , R ⁵⁵ and R ⁵⁶ , and R ⁵⁷ and R ⁵⁸ is preferably a hydrogen atom and the other is an alkyl group.

Q is not particularly limited as long as it is a polar group having hydrogen bonding properties. Preferably, hydroxyl group, carboxyl group, salt of carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2-hydroxyethylammonium, tetrabutylammonium, trimethylbenzylammonium, dimethylphenyl) Ammonium, etc.), pyridinium salts, etc.), amides of carboxylic acids (N unsubstituted or N-mono lower alkyl substituted, such as —CONH ₂ , —CONHCH ₃ etc.) sulfo groups, sulfo group salts (cations forming salts) examples are the same as those described in the above carboxyl group) of the sulfonamide group (N unsubstituted, or N- mono-lower-alkyl _{substituents,} -SONH _2, such as -SO 2 NHCH _3), phospho group, a salt of phospho group (Cachi that forms salt Examples of emission are the same as those described in the above carboxyl group), phosphonamides (N unsubstituted, or N- mono-lower-alkyl substituents, for example, _{-OP (= O) (NH 2} ) 2, -OP (= O) (NHCH ₃ ) ₂ ), a ureido group (—NHCONH ₂ ), an amino group (—NH ₂ , —NHCH ₃ ) which is unsubstituted or monosubstituted at the N-position (wherein the lower alkyl group is a methyl group or Represents an ethyl group). A hydroxyl group, a carboxyl group, a sulfo group and a phospho group are more preferred, a hydroxyl group or a carboxyl group is more preferred, and a hydroxyl group is particularly preferred.

  The repeating unit represented by the general formula (2) is preferably a repeating unit derived from a (meth) acrylic monomer. Specific examples of the ethylenically unsaturated monomer for deriving the repeating unit M are shown below, but the present invention is not limited thereto.

  The fluoroaliphatic group polymer represented by the general formula (1) includes at least one repeating unit A, B and M, respectively. That is, in the above formula (1), i, j and k, which mean the number of types of each repeating unit, are each an integer of 1 or more. The fluoroaliphatic group polymer represented by the general formula (1) may contain two or more kinds of each repeating unit, and may contain repeating units other than the repeating units A, B and M. .

  For example, the fluoroaliphatic group-containing polymer may contain one type of repeating unit derived from a monomer selected from the following monomer group, or may contain two or more types.

Monomer group (1) Alkenes Ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-dodecene, 1 octadecene, 1-eicosene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3, 3, 3 -Trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride, etc .;
(2) Dienes 1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2-n-propyl-1,3-butadiene, 2,3-dimethyl-1,3 -Butadiene, 2-methyl-1,3-pentadiene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, 2-chloro- 1,3-butadiene, 1-bromo-1,3-butadiene, 1-chlorobutadiene, 2-fluoro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1,1,2-trichloro -1,3-butadiene and 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane and the like;
(3) Derivatives of α, β-unsaturated carboxylic acid (3a) Alkyl acrylates Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate , Amyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, tert-octyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 2-bromoethyl acrylate, 4-chlorobutyl acrylate, 2-cyanoethyl acrylate, 2-acetoxyethyl acrylate, methoxybenzyl Chryrate, 2-chlorocyclohexyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 2-methoxyethyl acrylate, ω-methoxypolyethylene glycol acrylate (number of added polyoxyethylene: n = 2 to 100), 3-methoxy Butyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2- (2-butoxyethoxy) ethyl acrylate, 1-bromo-2-methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate, glycidyl acrylate Such);
(3b) Alkyl methacrylates Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2 -Ethylhexyl methacrylate, n-octyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, allyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, cresyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, ω Methoxypolyethylene glycol methacrylate (number of added polyoxyethylene: n = 2 to 100), 2-acetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate Glycidyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanatoethyl methacrylate, etc .;
(3c) Diesters of unsaturated polycarboxylic acid dimethyl maleate, dibutyl maleate, dimethyl itaconate, dibutyl taconate,
Dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate, etc .;
(3d) Amides of α, β-unsaturated carboxylic acids N, N-dimethylacrylamide, N, N-diethylacrylamide, Nn-propylacrylamide, N-tertbutylacrylamide, N-tertoctylmethacrylamide, N- Cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-benzylacrylamide, N-acryloylmorpholine, diacetone acrylamide, N-methylmaleimide and the like;
(4) Unsaturated nitriles Acrylonitrile, methacrylonitrile, etc .;
(5) Styrene and its derivatives Styrene, vinyl toluene, ethyl styrene, p-tert butyl styrene, methyl p-vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, vinyl naphthalene, p-methoxy styrene, p-hydroxy Methyl styrene, p-acetoxy styrene, etc .;
(6) Vinyl esters Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, vinyl methoxyacetate, vinyl vinyl acetate, etc .;
(7) Vinyl ethers Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl Vinyl ether, n-eicosyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, fluorobutyl vinyl ether, fluorobutoxyethyl vinyl ether, etc .; and (8) other polymerizable monomers N-vinyl pyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, Methoxyethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline .

  In the general formula (1), a, b and c are mass percentages representing the polymerization ratio of the monomer for deriving each repeating unit, Σai represents a numerical value of 1 to 98% by mass, and Σbj represents 1 to 98% by mass. Σck represents a numerical value of 1 to 98% by mass. Σai is 5 to 40% by mass, Σbj is 5 to 40% by mass, Σck is preferably 20 to 90% by mass, Σai is 10 to 35% by mass, and Σbj is 10 to 35% by mass. And Σck is more preferably 30 to 80% by mass. The fluoroaliphatic group-containing polymer represented by the general formula (1) may contain a repeating unit other than the repeating units A, B and M, that is, Σai + Σbj + Σck <100% by mass. The repeating units other than the repeating units A, B and M are preferably not included, that is, Σai + Σbj + Σck = 100% by mass.

  In addition, it is preferable that the ratio of the repeating units A and B derived from the fluoroaliphatic group-containing monomer contained in the fluoroaliphatic group-containing polymer is within a predetermined range, since unevenness in the initial stage of drying can be further reduced. Specifically, the sum (Σai + Σbj) of the total mass Σai of the i-type repeating unit A and the total mass of the j-type repeating unit B (Σai + Σbj) is preferably 20 to 50% by mass, and 25 to 45% by mass. More preferably, it is more preferably 25 to 40% by mass. When (Σai + Σbj) is less than 20% by mass, the control of the liquid crystal compound at the air interface is not sufficient, and the effect of the present invention to reduce the unevenness of the optical film may be weak, and when it exceeds 50% by mass, When the liquid crystalline composition is applied to the surface (for example, the surface of a transparent support such as a polymer film), the applicability is not sufficient and repelling failure may occur. When (Σai + Σbj) is in the above range, there is no such problem, and unevenness during initial drying can be further reduced.

  From the same viewpoint, the ratio of Σai to Σai + Σbj (Σai / (Σai + Σbj)) is preferably 0.2 to 0.8, more preferably 0.3 to 0.6, More preferably, it is 35-0.55. When the ratio (Σai / (Σai + Σbj)) is less than 0.2, the liquid crystal compound is not sufficiently controlled at the air interface, and the effect of the present invention for reducing unevenness of the optical film may be weak. If it exceeds .8, the coating property when the liquid crystalline composition is applied to the surface (for example, the surface of a transparent support such as a polymer film) is not sufficient, and repelling failure may occur. It is preferable that Σai / (Σai + Σbj)) be in the above range because there is no such problem and unevenness during initial drying can be further reduced.

  Specific examples of fluoroaliphatic group-containing polymers that can be used in the present invention are summarized in the following table, but are not limited to the following specific examples. In the table below, repeating units A, B, and M are monomeric compound Nos. Derived from the respective repeating units. It is specified by.

  The liquid crystal display composition of the present invention only needs to contain at least one kind of the fluoroaliphatic group-containing polymer, and of course may contain two or more kinds. In the composition, the addition amount of the fluoroaliphatic group-containing polymer is preferably 0.01 to 20% by mass, and 0.05 to 10% by mass of the mass of the liquid crystal compound (preferably a discotic liquid crystal compound). Is more preferable, and 0.1-5 mass% is further more preferable.

  In addition, a preferable range of the concentration C mass% of the fluoroaliphatic group-containing polymer in the composition (in the case where the composition is prepared as a coating solution or the like, solid content) is within the fluoroaliphatic group-containing polymer. It varies depending on the fluorine content F%. In order to further reduce unevenness in the initial stage of drying, the product of the concentration C% by mass of the fluoroaliphatic group-containing polymer and the fluorine content F% in the fluoroaliphatic group-containing polymer is 0.05 to 0.12. It is preferable that it is 0.06-0.09, and it is further more preferable that it is 0.06-0.08. When C × F is less than 0.05, liquid crystal compound control at the air interface is not sufficient, and the appearance characteristics (the degree of unevenness) of the optical film may be deteriorated. When an object is applied to the surface (for example, the surface of a transparent support such as a polymer film), the applicability is not sufficient, and the appearance characteristics of the optical film (repel failure may occur) may deteriorate. When C × F is within the above range, there is no such problem, and unevenness during initial drying can be further reduced.

  The optically anisotropic layer of the present invention is formed from liquid crystalline molecules. As the liquid crystal molecule, a rod-like liquid crystal molecule or a discotic liquid crystal molecule is preferable, and a discotic liquid crystal molecule is particularly preferable. Examples of rod-like liquid crystalline molecules include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. These low-molecular liquid crystal compounds preferably have a polymerizable group in the molecule (for example, described in paragraph number [0016] of JP-A No. 2000-304932). In addition to the above low-molecular liquid crystalline molecules, high-molecular liquid crystalline molecules can also be used. The high-molecular liquid crystalline molecule is a polymer having a side chain corresponding to the above low-molecular liquid crystalline molecule. Examples of the optical compensation sheet using polymer liquid crystalline molecules include compounds described in JP-A-5-53016.

  As the discotic liquid crystalline molecule, various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, quarterly chemistry review, No. 22). , Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 (1994)). Regarding the polymerization of discotic liquid crystalline molecules, the description of JP-A-8-27284 can be mentioned. In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferable, whereby the orientation state can be maintained even in the polymerization reaction. Examples thereof include compounds described in paragraph numbers [0151] to [0168] in JP-A 2000-155216. In order to optically compensate a liquid crystal cell in which rod-like liquid crystalline molecules such as STN mode are twisted, it is preferable that the discotic liquid crystalline molecules are also twisted. When an asymmetric carbon atom is introduced into the linking group, the discotic liquid crystal molecules can be twisted and aligned in a spiral shape. Further, even when an optically active compound containing an asymmetric carbon atom (chiral agent) is added to the optically anisotropic layer, the discotic liquid crystalline molecules can be twisted and aligned in a helical manner.

  Two or more kinds of discotic liquid crystal molecules may be used in combination. For example, a polymerizable discotic liquid crystalline molecule and a non-polymerizable discotic liquid crystalline molecule as described above can be used in combination. The non-polymerizable discotic liquid crystalline molecule is preferably a compound obtained by changing the polymerizable group of the polymerizable discotic liquid crystalline molecule described above to a hydrogen atom or an alkyl group. That is, examples of the non-polymerizable discotic liquid crystalline molecule include compounds described in Japanese Patent No. 2640083.

[Other compositions of optically anisotropic layer]
Along with the above liquid crystal molecules, a plasticizer, a surfactant, a polymerizable monomer, a polymer, or the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal molecules, and the like. It is preferable that the compound has compatibility with the liquid crystal molecules and can change the tilt angle of the liquid crystal molecules or does not inhibit the alignment.

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

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specific examples include compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725. The polymer used together with the discotic liquid crystalline molecules is preferably capable of changing the tilt angle of the discotic liquid crystalline molecules. A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and in the range of 0.1 to 3% by mass with respect to the liquid crystal compound so as not to disturb the alignment of the liquid crystal molecules. It is more preferable. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline molecule is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

  The optically anisotropic layer is a liquid crystalline molecule, or the following polymerizable initiator or any additive (eg, plasticizer, polymerizable monomer, surfactant, cellulose ester, 1,3,5-triazine compound, chiral It is formed by applying a coating solution containing an agent on the alignment film. As the solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Of these, alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

[Fixing the alignment state of liquid crystalline molecules]
The liquid crystalline molecules are preferably substantially uniformly aligned, more preferably fixed in a substantially uniformly aligned state, and the liquid crystalline molecules are fixed by a polymerization reaction. Is most preferred. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of photopolymerization initiators include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon-substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970). The amount of the photopolymerization initiator used is preferably 0.01 to 20% by weight, more preferably 0.5 to 5% by weight, based on the solid content of the coating solution. Light irradiation for polymerization of discotic liquid crystalline molecules is preferably performed using ultraviolet rays. The irradiation energy is preferably 20 mJ / cm ^{2 to} 50 J / cm ² , and more preferably 100 to 800 mJ / cm ² . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.

  The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 0.7 to 5 μm. However, depending on the mode of the liquid crystal cell, the optically anisotropic layer may be thickened (3 to 10 μm) in order to obtain high optical anisotropy. As described above, the alignment state of the liquid crystalline molecules in the optically anisotropic layer is determined according to the type of display mode of the liquid crystal cell. Specifically, the alignment state of liquid crystalline molecules is controlled by the type of liquid crystalline molecules, the type of alignment film, and the use of additives (eg, plasticizers, polymers, surfactants) in the optically anisotropic layer. The

  As described above, the optical compensation sheet of the present invention is manufactured. As described above, the optical compensation sheet of the present invention has a layer structure in which a transparent support that has been subjected to adhesion treatment in advance, an alignment film, and an optically anisotropic layer are laminated in this order. The optical compensation sheet of the present invention exhibits its functions remarkably by being bonded to a polarizing plate or used as a protective film for a polarizing plate. Hereinafter, the polarizing plate and its production will be described in detail.

<Polarizing plate>
A polarizing plate usually comprises a polarizing film and transparent protective films on both sides thereof. That the protective film is transparent means that the light transmittance is 80% or more. As the transparent protective film, generally a cellulose ester film, preferably an acetyl cellulose film is used. The cellulose ester film is preferably formed by the solvent cast method described in the transparent support. The thickness of the transparent protective film is preferably 20 to 200 μm, and more preferably 30 to 100 μm. Especially preferably, it is 30-80 micrometers.

  In the present invention, the optical compensation sheet of the present invention is used instead of the transparent protective film on one side of the polarizing plate. That is, in the polarizing plate of the present invention, a transparent protective film, a polarizing film, and the optical compensation sheet are laminated in this order. When the polarizing plate according to the present invention is attached to a liquid crystal display device, a liquid crystal display device having excellent optical characteristics and high display quality can be obtained.

[Surface treatment of optical compensation sheet]
When the optical compensation sheet is used instead of the transparent protective film of the polarizing plate, adhesion between the optical compensation sheet and the polarizing film may be a problem. In the present invention, it is preferable to improve the adhesion between the optical compensation sheet and the polarizing film by surface-treating the surface of the optical compensation sheet on the polarizing film side. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, ozone treatment, acid treatment, and alkali treatment. Examples of the treatment method such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, ozone treatment, acid treatment, and alkali treatment include the contents described in pages 30 to 31 of the public technical number 2001-1745. Can be mentioned. In the present invention, it is preferable to perform an alkali treatment, and examples thereof include the same contents as described in the saponification treatment of the above-described film.

[Polarizing film]
The polarizing film used in the present invention is usually preferably a coating type polarizing film represented by Optiva Inc., or a polarizing film composed of a binder and iodine or a dichroic dye. Iodine and dichroic dye in the polarizing film exhibit deflection performance by being oriented in the binder. It is preferable that the iodine and the dichroic dye are aligned along the binder molecule, or the dichroic dye is aligned in one direction by self-assembly such as liquid crystal. At present, a commercially available polarizing film is produced by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing iodine or dichroic dye to penetrate into the binder. Is common. The commercially available polarizing film has iodine or dichroic dye distributed about 4 μm (about 8 μm on both sides) from the polymer surface, and a thickness of at least 10 μm is necessary to obtain sufficient polarization performance. The penetrability can be controlled by the solution concentration of iodine or dichroic dye, the temperature of the bath, and the immersion time. As described above, the lower limit of the binder thickness is preferably 10 μm. The upper limit of the thickness is preferably as thin as possible from the viewpoint of light leakage of the liquid crystal display device. It is preferably not more than a commercially available polarizing plate (about 30 μm), preferably 25 μm or less, and more preferably 20 μm or less. When the thickness is 20 μm or less, the light leakage phenomenon is not observed on a 17-inch liquid crystal display device.

  The binder of the polarizing film may be cross-linked. As the crosslinked binder, a polymer that can be crosslinked per se can be used. A polarizing film can be formed by reacting a polymer having a functional group or a binder obtained by introducing a functional group into a polymer between the binders by light, heat, or pH change. Moreover, you may introduce | transduce a crosslinked structure into a polymer with a crosslinking agent. Crosslinking is generally carried out by applying a coating solution containing a polymer or a mixture of a polymer and a crosslinking agent on a transparent support and then heating. Since it is only necessary to ensure durability at the stage of the final product, the crosslinking treatment may be performed at any stage until the final polarizing plate is obtained.

  As the binder for the polarizing film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. Examples of the polymer include the same polymers as those described in the alignment film. Most preferred are polyvinyl alcohol and modified polyvinyl alcohol. The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509 and JP-A-9-316127. Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

  The addition amount of the crosslinking agent in the binder is preferably 0.1 to 20% by mass with respect to the binder. The orientation of the polarizing element and the wet heat resistance of the polarizing film are improved. The alignment film contains a certain amount of a crosslinking agent that has not reacted even after the crosslinking reaction has been completed. However, the amount of the remaining crosslinking agent is preferably 1.0% by mass or less and more preferably 0.5% by mass or less in the alignment film. In this way, even if the polarizing film is incorporated in a liquid crystal display device and used for a long time or left in a high temperature and high humidity atmosphere for a long time, the degree of polarization does not decrease. About a crosslinking agent, the description of the US reissue patent 23297 is mentioned. Boron compounds (eg, boric acid, borax) can also be used as a crosslinking agent.

  As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo, amino, hydroxyl). Examples of the dichroic dye include compounds described in, for example, the Japan Society for Invention and Innovation, Japanese Patent No. 2001-1745, page 58 (issued on March 15, 2001).

  In order to increase the contrast ratio of the liquid crystal display device, the transmittance of the polarizing plate is preferably higher and the degree of polarization is preferably higher. The transmittance of the polarizing plate is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and most preferably in the range of 40 to 50% with respect to light having a wavelength of 550 nm. . The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100% in light having a wavelength of 550 nm.

  When the polarizing film and the optical compensation sheet are arranged via an adhesive, the adhesive is a polyvinyl alcohol resin (including a modified polyvinyl alcohol by an acetoacetyl group, a sulfonic acid group, a carboxyl group, or an oxyalkylene group) or an aqueous boron compound solution. Can be used. A polyvinyl alcohol resin is preferred. The thickness of the adhesive layer is preferably in the range of 0.01 to 10 μm after drying, and particularly preferably in the range of 0.05 to 5 μm.

[Production of polarizing plate]
From the viewpoint of yield, the polarizing film is stretched by tilting the binder at an angle of 10 to 80 degrees with respect to the longitudinal direction (MD direction) of the polarizing film (stretching method), or rubbed (rubbing method). It is preferable to dye with a dichroic dye. The tilt angle is preferably stretched so as to match the angle formed between the transmission axis of the two polarizing plates bonded to both sides of the liquid crystal cell constituting the LCD and the vertical or horizontal direction of the liquid crystal cell. A normal inclination angle is 45 °. Recently, however, devices that are not necessarily 45 ° have been developed for transmissive, reflective, and transflective LCDs, and it is preferable that the stretching direction can be arbitrarily adjusted in accordance with the design of the LCD.

  In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. Moreover, you may implement wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 10.0 times. The stretching step may be performed in several steps including oblique stretching. By dividing into several times, it is possible to stretch more uniformly even at high magnification. Before the oblique stretching, a slight stretching (a degree to prevent shrinkage in the width direction) may be performed horizontally or vertically. Stretching can be performed by performing tenter stretching in biaxial stretching in different steps. The biaxial stretching is the same as the stretching method performed in normal film formation. In biaxial stretching, stretching is performed at different speeds on the left and right, so that the thickness of the binder film before stretching needs to be different on the left and right. In casting film formation, the flow rate of the binder solution can be differentiated between the left and right sides by tapering the die. As described above, a binder film that is obliquely stretched by 10 to 80 degrees with respect to the MD direction of the polarizing film is manufactured.

  In the rubbing method, a rubbing treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, orientation is obtained by rubbing the surface of the film in a certain direction using paper, gauze, felt, rubber, nylon, or polyester fiber. Generally, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are planted on average. It is preferable to carry out using a rubbing roll in which the roundness, cylindricity, and deflection (eccentricity) of the roll itself are all 30 μm or less. The wrap angle of the film on the rubbing roll is preferably 0.1 to 90 °. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 ° or more. When rubbing a long film, the film is preferably transported at a speed of 1 to 100 m / min in a constant tension state by a transport device. The rubbing roll is preferably rotatable in the horizontal direction with respect to the film traveling direction for setting an arbitrary rubbing angle. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 °. When used in a liquid crystal display device, the angle is preferably 40 to 50 °. 45 ° is particularly preferred.

It is preferable to dispose the transparent protective film on the surface of the polarizing film opposite to the optical compensation sheet (arrangement of optical compensation sheet / polarizing film / transparent protective film). It is also preferable that the transparent protective film is provided with an antireflection film having an outermost surface having antifouling properties and scratch resistance. Any conventionally known antireflection film can be used.
As described above, the polarizing plate of the present invention is produced. The optical compensation sheet of the present invention or the polarizing plate using the optical compensation sheet is advantageously used in a liquid crystal display device, particularly a transmissive liquid crystal display device. Hereinafter, a liquid crystal display device, particularly a transmissive liquid crystal display device and its manufacture will be described in detail.

"Liquid Crystal Display"
The transmissive liquid crystal display device of the present invention comprises a liquid crystal cell and two polarizing plates arranged on both sides thereof. The liquid crystal cell carries a liquid crystal between two electrode substrates.
One optical compensation sheet is disposed between the liquid crystal cell and one polarizing plate, or two optical compensation sheets are disposed between the liquid crystal cell and both polarizing plates. A preferred form of the optically anisotropic layer in each liquid crystal mode will be described below. In a preferable form of the optically anisotropic layer in each liquid crystal mode, the optical compensation sheet of the present invention or the polarizing plate using the optical compensation sheet can be optically compensated advantageously.

(TN mode liquid crystal display)
The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and many publications are cited. The alignment state in the liquid crystal cell in the TN mode black display is an alignment state in which the rod-like liquid crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie in the vicinity of the cell substrate.

(OCB mode liquid crystal display)
The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between an upper portion and a lower portion of the liquid crystal cell. Examples of the liquid crystal display device using the bend alignment mode liquid crystal cell include devices disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode. Similarly to the TN mode, the liquid crystal cell in the OCB mode is in a black display, and the alignment state in the liquid crystal cell is such that the rod-like liquid crystal molecules rise in the center of the cell and the rod-like liquid crystal molecules lie in the vicinity of the cell substrate. .

(VA mode liquid crystal display device)
In a VA mode liquid crystal cell, rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied. The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). 176625) (2) Liquid crystal cell (SID97, Digest of tech. Papers (Preliminary Proceed) 28 (1997) 845 in which the VA mode is converted into a multi-domain (MVA mode) for widening the viewing angle ), (3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary collections 58-59 of the Japan Liquid Crystal Society) (1998)) and (4) SURVAVAL mode liquid crystal cells (announced at LCD International 98).

(Other liquid crystal display devices)
The ECB mode and STN mode liquid crystal display devices can be optically compensated in the same way as described above.

Examples of the method for producing an optical compensation film, the optical compensation film, the polarizing plate, and the liquid crystal display device of the present invention are shown below, but the present invention is not limited thereto.
(Preparation of transparent support)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.

Cellulose acetate solution composition Cellulose acetate with an acetylation degree of 60.9% 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first solvent) 300 parts by weight Methanol (second solvent) 45 parts by weight Dye (manufactured by Sumika Fine Chemical Co., Ltd., 360FP) 0.0009 parts by weight In another mixing tank, 16 parts by weight of the following retardation increasing agent, 80 parts by weight of methylene chloride, and methanol 20 A part by mass was added and stirred while heating to prepare a retardation increasing agent solution. A dope was prepared by mixing 464 parts by mass of the cellulose acetate solution having the above composition with 36 parts by mass of the retardation increasing agent solution and 1.1 parts by mass of silica fine particles (R972, manufactured by Irosil) and stirring sufficiently. The addition amount of the retardation increasing agent was 5.0 parts by mass with respect to 100 parts by mass of cellulose acetate. Moreover, the addition amount of silica fine particles was 0.15 mass part with respect to 100 mass parts of cellulose acetate.

  The obtained dope was cast using a band casting machine. After the film surface temperature on the band reached 40 ° C., the film was dried for 1 minute, peeled off, and then dried with a cellulose acetate film CA-1 (thickness 100 μm) having a residual solvent amount of 0.3% by weight. Manufactured. When the retardation of the produced cellulose acetate film CA-1 was measured, the retardation Rth in the thickness direction was 85 nm, and the in-plane retardation Re was 7 nm.

(Saponification treatment)
A cellulose acetate film (CA-1) is passed through a dielectric heating roll having a temperature of 60 ° C. and heated to a film surface temperature of 40 ° C., and then an alkali solution (S-1) having the composition shown below is attached to a rod coater. It was applied at a coating amount of 15 cc / m ² and heated at 110 ° C. for 15 seconds under a steam far infrared heater manufactured by Noritake Co., Ltd. 3 cc / m ^{2 was} applied. The film temperature at this time was 40 degreeC. Next, washing with a fountain coater and draining with an air knife were repeated three times, and then the film was retained in a drying zone at 70 ° C. for 5 seconds for drying.

Alkaline solution (S-1) composition Potassium hydroxide 8.55 mass%
23.235% by weight of water
Isopropanol 54.20% by mass
Surfactant _{(K-1: C 14 H} 29 O (CH 2 CH 2 O) 20 H) 1.0 wt%
Propylene glycol 13.0% by mass
Antifoaming agent Surfinol DF110D (manufactured by Nissin Chemical Industry Co., Ltd.) 0.015% by mass
(Formation of alignment film)
On this surface-treated film, an alignment film coating solution having the composition shown in the following table was applied by a rod coater at a coating rate of 28 ml / m ² . Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds. When the pH of the coated surface after drying was measured, the value was 4.1. In addition, the pH values at the center and the left and right ends in the coating width direction were in the range of 4.00 to 4.20.

  In addition, the modified polyvinyl alcohol and carboxylic acid compound in the said table | surface show the compound represented by a following formula.

  Next, the rubbing process was implemented in the longitudinal direction of the film.

(Formation of optically anisotropic layer)
A discotic liquid crystal coating solution (DA-1) having the following composition is applied with a # 4 wire bar coater, heated in a high-temperature bath at 125 ° C. for 3 minutes to align the discotic liquid crystal, and then a high-pressure mercury lamp is used. Then, UV was irradiated at 500 mJ / cm ² , and the optical compensation film KS-1 was prepared according to the law up to room temperature.

Discotic liquid crystal coating solution (DA-1)
9.1 parts by mass of the following discotic liquid crystal DLC-A: ethylene oxide-modified trimethylolpropane acrylate (V # 360, Osaka Organic Chemical Co., Ltd.) 0.9 parts by mass Cellulose acetate butyrate (CAB551-0.2 Eastman Chemical) 0.2 parts by mass Cellulose acetate butyrate (CAB531-1 Eastman Chemical) 0.05 parts by mass Irgacure 907 3.0 parts by mass Kayacure DETX (manufactured by Nippon Kayaku Co., Ltd.) 0.1 parts by mass Methyl ethyl ketone 25. 9 parts by mass

(Appearance evaluation)
About the produced optical compensation film, the orientation of a liquid crystal compound layer, the bright spot generation | occurrence | production degree, and the spot failure were evaluated by external appearance observation. The results are shown in Table 4. In addition, the symbol in a table | surface shows the meaning of the following symbols.

<Orientation of liquid crystal compound layer>
○: No orientation failure occurred with the naked eye.
Δ: Some orientation failure was observed with the naked eye.
X: Orientation defects were clearly observed with the naked eye.

<Bright spot generation degree>
○: Bright spot defects could not be recognized with the naked eye.
Δ: Some bright spot defects were observed with the naked eye.
X: Bright spot defects were clearly observed with the naked eye.

<Spot failure>
○: Spots could not be recognized with the naked eye.
Δ: Some spots were observed with the naked eye.
X: Spots were clearly observed with the naked eye.

  From Table 4, in Examples 1-4 whose solid content concentration is 0.5-2.0 mass%, generation | occurrence | production of the spot was hardly seen and generation | occurrence | production of the bright spot was not seen. However, in Comparative Examples 1 and 2 where the solid content concentration was higher than 2.0%, spots were generated, and bright spot defects were observed on the optical compensation film. In particular, in Comparative Example 2 having a high solid content concentration, the occurrence of bright spot defects was noticeable.

It is the schematic which shows the manufacturing method of an optical compensation sheet.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Cellulose ester film, 10 '... Saponified cellulose ester film, 12 ... Alkaline aqueous solution, 14 ... Plasticizer, 16 ... Alignment film forming material, 18 ... Alignment film, 20 Liquid crystal layer

Claims (10)

After the adhesion providing treatment is performed on the transparent support, the alignment film forming composition is applied to form an alignment film, and a liquid crystalline compound containing a liquid crystalline compound is applied thereon to form an optically anisotropic layer. In the manufacturing method of the optical compensation film formed by forming
The method for producing an optical compensation film, wherein the coating solution containing the composition for forming an alignment film has a solid content concentration of 0.5 to 2.0% by mass. The alignment film-forming composition contains polyvinyl alcohol and / or modified polyvinyl alcohol as a main component,
The method for producing an optical compensation film according to claim 1, wherein the alignment film is a cured film formed by applying and drying the composition for forming an alignment film.   The method for producing an optical compensation film according to claim 1, wherein the composition for forming an alignment film contains at least one organic carboxylic acid compound containing at least one polar group. The adhesion imparting treatment (a) an application step of applying an alkaline aqueous solution containing at least water, an organic solvent and an alkaline agent to the transparent support;
(B) a saponification treatment step of saponifying the transparent support with the aqueous alkali solution and setting the amount of the plasticizer on the surface of the saponification treatment surface of the transparent support to 0.25 or less as measured by the ATR / IR method. 4. The method for producing an optical compensation film according to claim 1, wherein the transparent support is saponified.   The method for producing an optical compensation film according to claim 1, wherein the transparent support is a cellulose ester film. 6. The method for producing an optical compensation film according to claim 1, wherein the liquid crystal compound contains at least one fluoroaliphatic group-containing polymer represented by the following general formula (1).

In the general formula (1), i and j each represent an integer of 1 or more, meaning that each repeating unit includes i and j types, respectively; M is derived from an ethylenically unsaturated monomer, and k ( k is an integer greater than or equal to 1) types of repeating units; a, b and c are mass percentages representing a polymerization ratio, Σai represents a numerical value of 1 to 98% by mass, Σbj represents 1 to 98% by mass Σck represents a numerical value of 1 to 98% by mass; R ¹¹ and R ¹² each represent a hydrogen atom or a methyl group; X ¹ and X ² represent an oxygen atom, a sulfur atom, or —N (R ¹³ )-, R ¹³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; m1 and m2 each represent an integer of 1 to 6; and n1 represents an integer of 0 to 3.   The optical compensation film manufactured by the manufacturing method of the optical compensation film in any one of Claim 1 to 6.   The optical compensation film according to claim 7, wherein the alignment film has a thickness of 0.07 to 0.35 μm.   A polarizing plate comprising the optical compensation film according to claim 7.   A liquid crystal display device comprising the optical compensation film according to claim 7.

Images