JPWO2008072480A1 - Optical compensation film, method for producing optical compensation film, polarizing plate and liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide an optical compensation film and an optical compensation film that are excellent in productivity, have few orientation defects in the optically anisotropic layer, and have excellent wet heat durability in the adhesion between the support and the optically anisotropic layer. The object of the present invention is to provide a manufacturing method, a polarizing plate and a liquid crystal display device, the purpose of which is an optical compensation film having an intermediate layer and an optically anisotropic layer in this order on a transparent support, This was achieved by an optical compensation film comprising a urethane acrylate oligomer or a cured product of an acrylate oligomer, wherein the optically anisotropic layer is a layer in which the orientation of a substantially vertically aligned rod-like liquid crystal is fixed.

Description

  The present invention relates to an optical compensation film, a method for producing an optical compensation film, a polarizing plate, and a liquid crystal display device. More specifically, the productivity and the orientation of an optically anisotropic layer are small, and a support and an optically anisotropic layer are provided. The present invention relates to an optical compensation film having excellent wet heat durability in adhesiveness, a method for producing the optical compensation film, a polarizing plate, and a liquid crystal display device.

  As the liquid crystal display becomes larger, the demand for wide viewing angle is increasing, and various methods have been proposed for the liquid crystal cell type. Various alignment methods have been studied, and as one of them, a method of vertically aligning a liquid crystal material using a vertical alignment film is known (for example, see Patent Documents 1 and 2).

  In addition, as an optical compensation film in which a liquid crystal material is vertically aligned, it is disclosed that a liquid crystal material is vertically aligned on a modified polyvinyl alcohol that has been rubbed (see, for example, Patent Documents 3 and 4).

  However, when an alignment layer made of a water-soluble compound is bonded to a polarizer to be processed as a polarizing plate, a part of the alignment layer may be eluted in the alkaline aqueous solution during saponification treatment, which may cause film peeling. In general, since water-soluble compounds do not have good adhesion to a transparent support, it is necessary to perform pretreatment such as corona treatment, glow discharge treatment, and saponification treatment on the transparent support. .

  Moreover, an optical compensation film using a vertical alignment film made of a crosslinked product of an acrylic block polymer is disclosed (for example, see Patent Document 5).

  However, along with the improvement in performance of optical compensation films and the like, the vertical alignment film has been required to have durability and reliability. There was a problem that the adhesion was insufficient and the film was easily peeled off at the interface.

  On the other hand, as a method not using a vertical alignment film, a vertical alignment film is used for a side chain type liquid crystal polymer containing a monomer unit containing a liquid crystalline fragment side chain and a monomer unit containing a non-liquid crystalline fragment side chain. It is disclosed that a homeotropic alignment liquid crystal film can be produced by homeotropic alignment on a substrate (see, for example, Patent Document 6).

  Furthermore, it is disclosed that a vertical alignment can be obtained even if the substrate is not subjected to an alignment treatment by containing an appropriate surfactant in the polymerizable liquid crystal composition (see, for example, Patent Document 7). ). However, neither can solve the above-mentioned adhesion problem.

  In addition, it is known that a layer obtained by curing an ultraviolet curable resin is rubbed into an alignment film (see, for example, Patent Document 8). However, according to Patent Document 8, since a layer formed by curing a polymerizable liquid crystal is provided on an alignment film obtained by rubbing a layer obtained by completely curing an ultraviolet curable resin, there is a significant problem with the above-described adhesion. .

In addition, it is known that an alignment film is formed using a composition in which a monomer or oligomer having an ethylenically unsaturated bond is added to a polymer (see, for example, Patent Document 9). However, it has been very difficult to prevent the non-aqueous solvent-soluble polymer from being dissolved and mixed into the liquid crystal layer and to achieve adhesion between the alignment film and the liquid crystal layer.
JP-A-3-7913 Japanese Patent Laid-Open No. 3-186818 JP 2006-98750 A JP 2006-215093 A JP 2005-148473 A JP 2002-333642 A JP 2005-196221 A JP 2003-14935 A JP 2004-331888 A

  Accordingly, an object of the present invention is to provide an optical compensation film and an optical compensation having excellent productivity, few orientation defects in the optically anisotropic layer, and excellent wet heat durability in the adhesion between the support and the optically anisotropic layer. It is providing the manufacturing method of a film, a polarizing plate, and a liquid crystal display device.

  The above object of the present invention is achieved by the following configurations.

  1. An optical compensation film having an intermediate layer and an optically anisotropic layer in this order on a transparent support, the intermediate layer comprising a cured product of a urethane acrylate oligomer or an acrylate oligomer, wherein the optically anisotropic layer is substantially An optical compensation film characterized in that it is a layer in which the orientation of a vertically aligned rod-like liquid crystal is fixed.

  2. 2. The optical compensation film as described in 1 above, wherein the urethane acrylate oligomer or acrylate oligomer satisfies the following formulas 1 to 3.

Formula 1 1500 ≦ Mw ≦ 6000
Formula 2 2 ≦ number of oligomer functional groups ≦ 4
Formula 3 500 ≦ Mw / number of oligomer functional groups ≦ 3000
(Wherein, Mw represents the weight average molecular weight of the oligomer.)
3. 3. The optical compensation film as described in 1 or 2 above, wherein the intermediate layer comprises a cured product of urethane acrylate oligomer.

  4). 4. The optical compensation film as described in 1 to 3, wherein the transparent support is a cellulose ester film satisfying the following formulas 4 to 6.

Formula 4 30 ≦ Ro ≦ 115 (nm)
Formula 5 100 ≦ Rt ≦ 250 (nm)
Formula 6 1.6 ≦ Rt / Ro ≦ 4.4
However, said Ro and Rt are the retardation values represented by the following formula | equation.

Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(In the formula, the refractive index in the slow axis direction in the film plane is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, the refractive index in the thickness direction of the film is nz, d is the thickness of the film ( nm).)
5). 5. The optical compensation film as described in 4 above, wherein the cellulose ester film contains a cellulose ester satisfying the following formulas 7 to 8.

Formula 7 2.00 ≦ (X + Y) ≦ 2.60
Formula 8 0.10 ≦ Y ≦ 1.50
(In the formula, X and Y represent the acyl group substitution degree of the cellulose ester, X represents the acetyl group substitution degree, and Y represents the propionyl substitution degree.)
6). 6. A polarizing plate, wherein the optical compensation film according to any one of 1 to 5 is used on at least one surface.

  7). 7. A liquid crystal display device using the polarizing plate described in 6 above.

8). A method for producing an optical compensation film in which an intermediate layer and an optically anisotropic layer are provided in this order on a transparent support, comprising:
a) urethane acrylate oligomer or acrylate oligomer,
b) a photopolymerization initiator,
c) An intermediate layer composition composed of a solvent is applied, dried, and semi-cured by ultraviolet irradiation to form an intermediate layer, on which an optically different layer is a layer in which the alignment of substantially vertically aligned rod-like liquid crystals is fixed. A method for producing an optical compensation film, comprising forming an isotropic layer.

  9. 9. The method for producing an optical compensation film as described in 8 above, wherein the transparent support is a cellulose ester film that is stretched in at least one axial direction and satisfies the following formulas 4 to 6.

Formula 4 30 ≦ Ro ≦ 115 (nm)
Formula 5 100 ≦ Rt ≦ 250 (nm)
Formula 6 1.6 ≦ Rt / Ro ≦ 4.4
However, said Ro and Rt are the retardation values represented by the following formula | equation.

Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(In the formula, the refractive index in the slow axis direction in the film plane is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, the refractive index in the thickness direction of the film is nz, d is the thickness of the film ( nm).)
10. 9. The method for producing an optical compensation film as described in 8 above, wherein the intermediate layer is semi-cured so as to have a gel fraction of 30 to 80% by mass.

  According to the present invention, an optical compensation film having excellent productivity, less orientation defects in the optically anisotropic layer, and excellent wet heat durability in the adhesion between the support and the optically anisotropic layer, It is providing a manufacturing method, a polarizing plate, and a liquid crystal display device.

It is the schematic which shows an example of the tenter process used for this invention. It is a figure explaining the extending | stretching angle in an extending | stretching process.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  As a result of intensive studies on the above problems, the present inventors have found that there are few orientation defects in the optically anisotropic layer and a desirable state in which excellent adhesion between the support and the optically anisotropic layer can be obtained. An intermediate layer made of a cured product of urethane acrylate oligomer or acrylate oligomer is sufficiently cured to block the eluate from the support, and sufficient to obtain good adhesion to the optically anisotropic layer It has been found that it is necessary to leave an acrylate remaining. That is, with respect to the amount of ultraviolet rays irradiated when the intermediate layer is cured, the monomer is too sensitive to the amount of ultraviolet rays, and it is impossible to achieve both shielding and adhesion of the eluate, and the amount of ultraviolet rays is considerably high for polymers. Since many are necessary, it is difficult to achieve both the shielding property and the adhesion property of the eluate due to the occurrence of unevenness.

  On the other hand, the oligomer has a moderate sensitivity to the amount of ultraviolet rays and has been found to be able to stably produce a state in which the shielding property and adhesion of the eluate are compatible.

  That is, the optical compensation film of the present invention is an optical compensation film having an intermediate layer and an optically anisotropic layer in this order on a transparent support, and the intermediate layer is formed from a cured product of urethane acrylate oligomer or acrylate oligomer. Thus, the optically anisotropic layer is a layer in which the orientation of the vertically aligned rod-like liquid crystal is fixed.

  Above all, the urethane acrylate oligomer or acrylate oligomer is preferably a compound satisfying the following formulas 1 to 3.

Formula 1 1500 ≦ Mw ≦ 6000
Formula 2 2 ≦ number of oligomer functional groups ≦ 4
Formula 3 500 ≦ Mw / number of oligomer functional groups ≦ 3000
(Wherein, Mw represents the weight average molecular weight of the oligomer.)
As described above, the present inventors have found that each oligomer is classified as follows from the viewpoint of the degree of curing of the urethane acrylate oligomer or acrylate oligomer with respect to the amount of ultraviolet rays.

  High-hardness oligomer: A low molecular weight, multifunctional oligomer close to a monomer. The lower the molecular weight, the better the adhesion with a small amount of ultraviolet irradiation, but the lower the film strength. The higher the ultraviolet irradiation, the stronger the film strength but the lower the adhesion.

  Medium hardness oligomer: a medium molecular weight, bifunctional to tetrafunctional oligomer, and has a wide range of adhesion and film strength with respect to the amount of ultraviolet rays.

  Low-hardness oligomer: high molecular weight close to polymer, bifunctional oligomer. The higher the molecular weight, the more it is necessary to irradiate a large amount of ultraviolet rays to achieve both adhesion and film strength. Unevenness is also likely to occur.

  Therefore, the urethane acrylate oligomer or acrylate oligomer according to the present invention is preferably the above-mentioned medium hardness oligomer, and preferably satisfies the above formulas 1 to 3.

  Furthermore, when the transparent support is a cellulose ester film satisfying the following formulas 4 to 6 when mounted on a liquid crystal display device, the viewing angle widening performance is high, the color is good, and the orientation defect of the optical anisotropic layer In addition, the present invention has also been found to be particularly preferable for obtaining excellent adhesion between the support and the optically anisotropic layer.

Formula 4 30 ≦ Ro ≦ 115 (nm)
Formula 5 100 ≦ Rt ≦ 250 (nm)
Formula 6 1.6 ≦ Rt / Ro ≦ 4.4
However, said Ro and Rt are the retardation values represented by the following formula | equation.

Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(In the formula, the refractive index in the slow axis direction in the film plane is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, the refractive index in the thickness direction of the film is nz, d is the thickness of the film ( nm).)
The method for producing an optical compensation film of the present invention comprises a transparent support,
a) urethane acrylate oligomer or acrylate oligomer,
b) a photopolymerization initiator,
c) An intermediate layer composition composed of a solvent is applied, dried, and semi-cured by ultraviolet irradiation to form an intermediate layer, on which an optically different layer is a layer in which the alignment of substantially vertically aligned rod-like liquid crystals is fixed. An anisotropic layer is formed, and the transparent support is preferably a cellulose ester film, and the intermediate layer is preferably semi-cured so as to have a gel fraction of 30 to 80% by mass.

  Hereinafter, the present invention will be described in detail.

(Urethane acrylate oligomer)
The urethane acrylate oligomer used in the present invention is not particularly limited, but is preferably a urethane (meth) acrylate oligomer described in detail below, and the urethane (meth) acrylate oligomer is a (meth) acrylic type. It is obtained by reacting a polyol containing at least one polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate.

  In such a (meth) acrylic polyol, the (meth) acrylic acid alkyl ester constituting the (meth) acrylic polyol includes methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl ( In addition to (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, and other known (meth) acrylic acid alkyl esters. 1 type or 2 types or more are used.

  The method for producing such a (meth) acrylic polyol is not particularly limited. For example, (1) in the presence of a mercaptan (for example, mercaptoethanol, dodecanethiol, etc.) as a chain polymerization agent, the above (meth) acrylic is used. The acid alkyl ester (b1) is radically polymerized to obtain a one-terminal hydroxyl group-containing acrylic polymer or copolymer, and further a short-chain diol (for example, 1,4-butanediol, 3-methyl-1,5-pentanediol) , 1,6-hexanediol, propylene glycol, ethylene glycol, etc.), and the other one-terminal ester group is replaced with a hydroxyl group, (2) an organic halide having two or more starting points, or a sulfonyl halide compound Is used as an initiator to convert the alkyl (meth) acrylate (b1) A method in which a hydroxyl group-containing (meth) acrylate is bonded to both ends of a polymer or copolymer obtained by cal polymerization (both ends are hydroxyl groups based on a hydroxyl group-containing (meth) acrylate), and (3) a hydroxyl group-containing organic halogen. Living radical polymerization of the above (meth) acrylic acid alkyl ester (b1) using a compound as an initiator, and bonding a hydroxyl group-containing (meth) acrylate to the resulting polymer or copolymer (one end is an initiator) And the other end is a hydroxyl group based on a hydroxyl group-containing (meth) acrylate).

  Among these, “TEGO Diol BD 1000”, “TEGO Diol MD 1000N”, “TEGO Diol MD 1000X”, etc. manufactured by Tego Chemie Service are easily available as products manufactured by the method of (1) above.

  Furthermore, the type of the component other than the (meth) acrylic polyol in the polyol used in the present invention is not particularly limited, and examples thereof include polyether polyol, polyester polyol, polycarbonate polyol, polybutadiene polyol, polyolefin polyol and the like. It is done.

  In the present invention, the weight average molecular weight of the polyol containing at least one (meth) acrylic polyol is preferably 500 or more, more preferably 600 to 5000, and particularly preferably 750 to 2500. is there. If the molecular weight of the polyol is less than 500, the compatibility is poor.

  The polyisocyanate is not particularly limited, and examples thereof include aromatic, aliphatic, and alicyclic polyisocyanates, among which tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and modified diphenylmethane. Diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4- Diisocyanates such as tetramethylene diisocyanate and naphthalene diisocyanate or trimers thereof are preferred. It is needed. The molecular weight of the polyisocyanate compound is preferably 150 to 700 from the viewpoint of reactivity with a hydroxyl group.

  The hydroxyl group-containing (meth) acrylate is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxyethylacryloyl. Phosphate, 4-hydroxybutyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, glycerol di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, caprolactone Modified 2-hydroxyethyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone modified 2-hydroxyethyl (meth) acrylate Chromatography, tri propylene glycol (meth) acrylate, 2-hydroxy-3-chloropropyl (meth) acrylate, glycerol mono (meth) acrylate, glycerol methacrylate acrylate.

  About the manufacturing method of the urethane (meth) acrylate oligomer used in the present invention, from the viewpoint of stability of reaction control and shortening of manufacturing time, after reacting polyol and polyisocyanate to obtain a terminal isocyanate group-containing compound, Next, a method of reacting the terminal isocyanate group-containing compound with a hydroxyl group-containing (meth) acrylate is preferably used.

  In the above method, after reacting polyol and polyisocyanate at a reaction molar ratio of k: k + 1 (molar ratio) (k is an integer of 1 or more), the terminal isocyanate group-containing compound further contains a hydroxyl group ( It is preferred to react the meth) acrylate at a reaction molar ratio of 1: 2.

  In these reactions, it is also preferable to use a catalyst such as dibutyltin dilaurate for the purpose of promoting the reaction.

  In the present invention, in the urethane (meth) acrylate oligomer, the (meth) acrylic polyol is preferably reacted in an amount of 20% by mass or more based on the total of the polyol, the polyisocyanate, and the hydroxyl group-containing (meth) acrylate. Is preferably 30 to 80% by mass, more preferably 40 to 70% by mass. If the ratio is less than 20% by mass, the compatibility with the acrylic resin tends to be poor, which is not preferable.

  Furthermore, the urethane acrylate oligomer used in the present invention is preferably a urethane (meth) acrylate oligomer represented by the following general formula (1).

Here, R ¹ is a urethane bond residue of a polyol compound, R ² is a urethane bond residue of an allophanate-modified polyisocyanate compound represented by the following general formula (2), and R ³ is a hydroxyl group-containing (meth) acrylate compound The urethane bond residue, n is an integer of 1-10.

Here, R ⁴ and R ⁵ are isocyanate residues of the diisocyanate compound, which may be the same or different, and R ⁶ is a monool residue.

  The polyol compound is not particularly limited. For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, 1,4-butanediol, Polybutylene glycol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, polycaprolactone, trimethylolethane, trimethylolpropane, polytrimethylolpropane, pentaerythritol, polypentaerythritol, sorbitol, mannitol Arabitol, xylitol, galactitol, glycerin, polyglycerin, polytet Polyhydric alcohols such as methylene glycol and hydrogenated polybutadiene polyol, polyether polyols having at least one structure of polyethylene oxide, polypropylene oxide, block / random copolymerization of ethylene oxide / propylene oxide, the polyhydric alcohol or poly Caprolactone modifications such as polyester polyols and caprolactone-modified polytetramethylene polyols, which are condensates of ether polyols with polybasic acids such as maleic anhydride, maleic anhydride, fumaric acid, itaconic anhydride, itaconic acid, adipic acid, and isophthalic acid Examples include polyols, polyolefin-based polyols, polycarbonate-based polyols, and 2,2-bis (hydroxymethyl) butyric acid, tartaric acid, 2,4-dihydroxybenzoic acid. 3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxyethyl) propionic acid, 2,2-bis (hydroxypropyl) propionic acid, dihydroxymethylacetic acid, bis Carboxyl group-containing polyols such as (4-hydroxyphenyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid and homogentisic acid, and sulfonic acid groups or sulfonate groups such as sodium 1,4-butanediolsulfonate Also included are polyols and the like, which are used alone or in combination of two or more.

  Among the above polyol-based compounds, polycarbonate-based polyols are particularly preferable in terms of adhesiveness, water resistance, and heat and humidity resistance.

  The allophanate-modified polyisocyanate compound used in the present invention is not particularly limited as long as it has a structure represented by the general formula (2), and examples thereof include allophanate-modified products of hexamethylene diisocyanate. May include commercial products such as “LVA-209”, “LVA-210”, and “LVA-211” manufactured by Nippon Polyurethane. Among these, an aliphatic polyisocyanate compound is particularly preferable in terms of weather resistance and heat resistance.

  The above-mentioned thing can be used for the hydroxyl-containing (meth) acrylate type compound used by this invention.

  The method for producing the urethane (meth) acrylate oligomer represented by the general formula (1) is not particularly limited, and usually the polyol compound, the allophanate-modified polyisocyanate compound, the hydroxyl group-containing (meth) acrylate compound, The reaction may be carried out in a batch or separately in the reactor, but the reaction product obtained by reacting the polyol compound and the allophanate-modified polyisocyanate compound in advance is reacted with the hydroxyl group-containing (meth) acrylate compound. However, it is useful in terms of reaction stability and reduction of by-products.

  For the reaction between the polyol compound and the allophanate-modified polyisocyanate compound, known reaction means can be used. At that time, for example, by setting the molar ratio of the isocyanate group in the allophanate-modified polyisocyanate compound to the hydroxyl group in the bifunctional polyol compound to about 2n: (2n-2) (n is an integer of 2 or more). The isocyanate group of the reaction product is allowed to remain and enables an addition reaction with a hydroxyl group-containing (meth) acrylate compound.

  Known reaction means can also be used for the addition reaction with the hydroxyl group-containing (meth) acrylate compound.

  In the reaction between the polyol compound and the allophanate-modified polyisocyanate compound, and the reaction product and the hydroxyl group-containing (meth) acrylate compound, a catalyst is preferably used for the purpose of accelerating the reaction. Examples thereof include organic metal compounds such as dibutyltin dilaurate, trimethyltin hydroxide, and tetra-n-butyltin, metals such as zinc octoate, tin octoate, cobalt naphthenate, stannous chloride, and stannic chloride. Salt, triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N ′, N′-tetramethyl-1, Amine catalysts such as 3-butanediamine and N-ethylmorpholine, bismuth nitrate, bismuth bromide In addition to bismuth iodide, bismuth sulfide, etc., organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, bismuth laurate Organic acid bismuth salts such as salts, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth bisneodecanoate, bismuth disalicylate, bismuth digallate, etc. Among them, dibutyltin dilaurate and 1,8-diazabicyclo [5,4,0] undecene are preferable.

  In the reaction between the polyol compound and the allophanate-modified polyisocyanate compound, and further in the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound, an organic solvent having no functional group that reacts with the isocyanate group, For example, organic solvents such as esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene can be used. The reaction temperature is preferably in the range of 30 to 90 ° C, particularly 40 to 90 ° C.

  The reaction molar ratio between the reaction product and the hydroxyl group-containing (meth) acrylate compound is, for example, that the allophanate-modified polyisocyanate compound has two isocyanate groups and the hydroxyl group-containing (meth) acrylate compound has one hydroxyl group. In this case, the reaction product: hydroxyl group-containing (meth) acrylate compound is about 1: 2, the allophanate-modified polyisocyanate compound has three isocyanate groups, and the hydroxyl group-containing (meth) acrylate compound has one hydroxyl group. In this case, the reaction product: hydroxyl group-containing (meth) acrylate compound is about 1: 4.

  In the addition reaction with the hydroxyl group-containing (meth) acrylate compound, a urethane (meth) acrylate oligomer is obtained by terminating the reaction when the residual isocyanate group content in the reaction system is 0.5% by mass or less. It is done.

  Thus, a urethane (meth) acrylate oligomer is obtained. In the present invention, it is preferable that the urethane (meth) acrylate oligomer or the acrylate oligomer described later satisfy the following formulas 1 to 3.

Formula 1 1500 ≦ Mw ≦ 6000
Formula 2 2 ≦ number of oligomer functional groups ≦ 4
Formula 3 500 ≦ Mw / number of oligomer functional groups ≦ 3000
(Wherein, Mw represents the weight average molecular weight of the oligomer.)
The weight average molecular weight (Mw) is preferably 1500 to 6000, and more preferably 2000 to 5000. When the weight average molecular weight is 1500 to 6000, it is preferable in terms of excellent compatibility with other resins and excellent adhesion to the optically anisotropic layer.

  The weight average molecular weight is a weight average molecular weight in terms of standard polystyrene molecular weight, and the column: Shodex GPC KF is used in high performance liquid chromatography (manufactured by Waters, Japan, “Waters 2695 (main body)” + “Waters 2414 (detector)”). −806 L (exclusion limit molecular weight: 2 × 107, separation range: 100 to 2 × 107, theoretical plate number: 10,000 plate / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm) It is measured by using three series.

  In addition, the urethane (meth) acrylate oligomer preferably has 2 to 4 functional groups of the oligomer in one molecule from the viewpoint of low cure shrinkage and excellent adhesion to a substrate film.

  Although the synthesis example of the urethane (meth) acrylate oligomer used for this invention is shown below, this invention is not limited to this.

[Synthesis Example 1]
In a four-necked flask equipped with a thermometer, a reflux cooling device, and a stirrer, 424 g (0.535 mol) of polycarbonate diol (manufactured by Asahi Kasei Corporation, “L5650J”, hydroxyl value = 141.5 mgKOH / g), allophanate-modified diisocyanate (Japan) “LVA-209” manufactured by Polyurethanes, 454 g (1.07 mol) of isocyanate group content = 19.8%) and 0.02 g of dibutyltin dilaurate were charged and reacted at 80 ° C. for 3 hours with stirring. Next, the mixture was cooled to 60 ° C., 124 g (1.07 mol) of 2-hydroxyethyl acrylate was added, and further reacted at 60 ° C. for 4 hours to obtain a urethane acrylate oligomer (weight average molecular weight 5400).

[Synthesis Example 2]
In a four-necked flask equipped with a thermometer, a reflux cooling device and a stirrer, 494 g (0.47 mol) of polycarbonate diol (manufactured by Asahi Kasei Corporation, “L5651”, hydroxyl value = 106.7 mg KOH / g), allophanate-modified diisocyanate (Japan) “LVA-209” manufactured by Polyurethanes Co., Ltd., isocyanate group content = 19.8%)
399 g (0.94 mol) and 0.02 g of dibutyltin dilaurate were added, the reaction was carried out at 80 ° C. for 3 hours with stirring, and then cooled to 60 ° C. to give 109 g of 2-hydroxyethyl acrylate (0.94 mol). The resulting mixture was further reacted at 60 ° C. for 4 hours to obtain a urethane acrylate oligomer (weight average molecular weight 12600).

  Furthermore, specific examples of the urethane acrylate oligomer used in the present invention include the following, but are not limited to these compounds.

MW number of functional groups (p) MW / p
NIPPON GOHSEI: Purple light UV-7605B 1100 6 183
NIPPON GOHSEI: Purple light UV-7600B 1400 6 233
NIPPON GOHSEI: Purple light UV-1700B 2000 10 200
NIPPON GOHSEI: Purple light UV-7550B 2400 3 800
NIPPON GOHSEI: Purple light UV-7510B 3500 3 1167
NIPPON GOHSEI: Purple light UV-3310B 5000 2 2500
NIPPON GOHSEI: Purple light UV-3210B 9000 2 4500
Shin-Nakamura Chemical Co., Ltd .: NK Oligo UA4100 1200 2 600
Shin-Nakamura Chemical: NK Oligo U-108A 1600 2 800
Shin-Nakamura Chemical: NK Oligo UA6100 2300 2 1150
Shin-Nakamura Chemical Co., Ltd .: NK Oligo U200AX 2700 2 1350
Arakawa Chemical: Beam Set 502H 4200 2 2100
Negami Kogyo: Art Resin UN7700 20000 2 10000
(Acrylate oligomer)
The acrylate oligomer used in the present invention is not particularly limited. However, the acrylate oligomer includes a compound of the following general formula (3), a hydroxy (meta) containing at least one free hydroxyl group and at least two (meth) acryl groups. ) An acrylate oligomer obtained by reaction with acrylate is preferred.

[Wherein R represents a C1-C4-alkyl group, an aryl group or a group R ¹ , and R ¹ represents

Wherein the groups R ^{2 to} R ⁶ are, independently of one another, H, C 1 -C 4 -alkyl, C 1 -C 4 -alkoxy, OH, phenyl, SH, SCH ₃ , SC ₂ H ₅ , F , Cl, Br, CN, COOH , COO- (C1~C17- alkyl), COO- (C5~C10- aryl), CF _3, N (alkyl) 2, N (alkyl) (aryl), N (aryl) 2, N ⁺ (alkyl) 3A-, N ⁺ H (alkyl) 2A-, A- represents an anion of an acid, and alkyl- or aryl- is C1-C10- unless otherwise stated. It represents an alkyl group or C5~C10- aryl group, and at least one of R ² to R ^6, but up to three, the group:

Is]
In the general formula (3), R preferably represents a methyl group, particularly preferably a phenyl group.

  Particularly preferred compounds of the general formula (3) are

It is.

  Aromatic chloroformates of general formula (3) (see J. Prakt. Chem. 313, 331 (1971), dito 317, 62, 73, 81 (1975)) are substituted phenols such as 4-chloro -5'-fluoro-2'-hydroxybenzophenone, 4-chloro-4'hydroxybenzophenone, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone, 4-fluoro-4'-hydroxybenzophenone, 2-hydroxybenzophenone 4-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,3,4-trihydroxybenzophenone, 2-hydroxy-thioxanthone, 3-hydroxy-thioxanthone, (4-hydroxyphenyl) -2-hydroxy-2- Propyl (For example, Houben-Weyl, Methoden der organischen Chemie, Bd. 8, Thieme-Verlag) by phosgenation according to standard methods known in the literature using phosgene. 1952, Trichlormethlorformia (Diphosgen), J. Prakt. Chem. 126, 210 (1930), dito 128, 233 (1930), Chem. Abstr. 95, 81766, J. Org. Chem. 50, 715 (1985). Org.Chem.41, 2070 (1976), Angew.Chem.89, 267 (1977), dem kristlinen Tri phosgen, Angew.Chem.99, 922 (1987), N, N′-Carbonylidiimidazolol order N, N′-Carbonyldi-s-triazole Fieser 1,116 (1967)), can be produced in good yield. .

  The hydroxy (meth) acrylate which reacts with the compound of general formula (3) to give the (meth) acrylate oligomer used in the present invention is at least 1, in particular 1 to 4, particularly preferably 1 to 2 Contains hydroxyl groups. In this case, the hydroxyl group is present in an alcohol esterified with (meth) acrylic acid or is primary to, for example, a (meth) acrylic group, in particular an acrylic group substituted, for example by a hydroxyalkyl group. Or it can also introduce | transduce into a molecule | numerator by Michael addition of a secondary amine.

  Furthermore, hydroxy (meth) acrylates contain at least 2, in particular 2 to 6, particularly preferably 2 to 4 acrylic or methacrylic groups in the molecule. Preferably this is an acrylic group and the corresponding hydroxy acrylate.

  Specifically, hydroxy (meth) acrylate is, for example, trimethylolpropane diacrylate and pentaerythritol triacrylate.

  Also included are epoxide acrylates obtained by reaction of epoxidized olefins, glycidyl esters of saturated or unsaturated carboxylic acids or glycidyl ethers of aliphatic or aromatic polyols with (meth) acrylic acid.

  Furthermore, urethane acrylates that can be produced, for example, by reacting polyisocyanates with hydroxyl group-containing (meth) acrylic esters also fall under this category.

  Preferred hydroxy (meth) acrylates are polyester- or polyether (meth) acrylates having at least one free hydroxyl group and 2 to 6, in particular 2 to 4, acrylic groups in the molecule.

  The polyester- or polyether (meth) acrylate can be prepared by esterification of a hydroxyl group-containing polyester or polyether using (meth) acrylic acid, which is known to those skilled in the art. , In an amount such that the desired number of free hydroxyl groups remain in the molecule.

  The molecular weight Mn of the hydroxyl group-containing polyester or polyether is preferably from 100 to 4000 (Mn is determined by gel permeation chromatography).

  Such hydroxyl group-containing polyesters are prepared, for example, by esterification of dicarboxylic acids or polycarboxylic acids with a polyol having at least 3 OH groups, optionally in the form of a mixture with diols, in a conventional manner. Can do. The starting materials for such hydroxy group-containing polyesters are known to those skilled in the art. Advantageously, as the dicarboxylic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, o-phthalic acid, their isomers and hydrogenation products and esterifiable derivatives such as anhydrides such as maleic anhydride or Dialkyl esters of the acids can be used. Polycarboxylic acids or anhydrides thereof include tri- or tetraacids such as trimellitic anhydride or benzenetetracarboxylic acid. As diols, in particular ethylene glycol, propylene glycol-1, 2 and -1,3, butanediol-1,4, hexanediol-1,6, neopentyl glycol, cyclohexanedimethanol and ethylene glycol and propylene glycol type poly This is the case for glycols. As the polyol, firstly, trimethylolpropane, glycerin or pentaerythritol or a dimer thereof such as sorbit may be mentioned. As diols or propanols, oxyalkylated (for example using ethylene oxide or propylene oxide) diols or polyols, in particular having an oxyalkylation degree of 0 to 10 for the respective hydroxy groups of the diol or polyol This is the case.

  Polyesterols also include polycaprolactone triols, the preparation of which is likewise known to those skilled in the art.

  Suitable hydroxyl group-containing polyethers are, for example, those which can be obtained by reacting polyhydric alcohols with different amounts of alkylene oxide, preferably ethylene oxide and / or propylene oxide, in a manner known per se.

  Preference is given to those polyol oxyalkylation products having a degree of oxyalkylation of 0 to 10 in particular for each hydroxyl group of the polyol, in particular at least two ether groups being present in the molecule. ing.

  In the production of the (meth) acrylate oligomer used in the present invention, the operation is performed particularly under moisture shielding. Suitable solvents are, for example, dry, non-nucleophilic solvents such as acetonitrile, dichloromethane, dichloroethane, tetrahydrofuran, toluene, xylene, chlorobenzene, acetate or chloroform.

  The reaction of the hydroxy (meth) acrylate with the chloroformate of the general formula (3) can be carried out at 0-100 ° C, especially 10-50 ° C. If the (meth) acrylate is a liquid, the solvent can be omitted completely or partially.

  The (meth) acrylate oligomer used in the present invention can be used alone or in the form of a mixture with another curable polymer or monomer as long as the effects of the present invention are not impaired.

  It is preferable that the (meth) acrylate oligomer used for this invention also satisfy | fills said Formulas 1-3 similarly to the said urethane (meth) acrylate oligomer.

[Synthesis example of (meth) acrylate oligomer]
To 100 g of polyether acrylate (Laromer (registered trademark) LR 8812), 5.75 g of chloroformate shown in Chemical formula 6 and 3.3 g of triethanolamine were added at room temperature. Subsequently, 300 ml of acetate was added. After 2 hours, the resulting triethanolammonium chloride was washed in a separatory funnel with distilled water. After separation of the aqueous phase, the acetate was distilled off to obtain a (meth) acrylate oligomer.

  Specific examples of the acrylate oligomer used in the present invention include the following, but are not limited to these compounds.

MW number of functional groups (p) MW / p
BASF made: Laromer LR8981 1300 3 433
BASF made: Laromer LR8985 1700 1.5 1133
(Formation of intermediate layer)
The intermediate layer composition forming the intermediate layer of the present invention preferably contains the urethane acrylate oligomer or acrylate oligomer, a photopolymerization initiator, and a solvent as main components.

  As the photopolymerization initiator used in the intermediate layer, a general polymerization initiator can be used.

  Specific examples of the photopolymerization initiator include benzoin and derivatives thereof, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and the like. You may use with a photosensitizer. The photopolymerization initiator can also be used as a photosensitizer. In addition, when using an epoxy acrylate photopolymerization initiator, a sensitizer such as n-butylamine, triethylamine, tri-n-butylphosphine can be used. It is preferable to contain 0.1-10 mass% of polymerization initiators with respect to a urethane acrylate oligomer or an acrylate oligomer, More preferably, it is 1-7 mass%.

  The solvent is not particularly limited, but specifically, it is preferable to apply a composition containing a solvent for dissolving the cellulose ester or a solvent for swelling. As a solvent to be used, it is also preferable to include a solvent to be dissolved in addition to a solvent to be dissolved and / or a mixture of solvents to be swollen, and they can be mixed at an appropriate ratio.

  Examples of the solvent for dissolving or swelling the cellulose ester include dioxane, acetone, methyl ethyl ketone, N, N-dimethylformamide, methyl acetate, ethyl acetate, trichloroethylene, methylene chloride, ethylene chloride, tetrachloroethane, trichloroethane, chloroform, propylene glycol monomethyl. Examples include ether and propylene glycol monomethyl ether acetate. Examples of the solvent that does not dissolve include methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, cyclohexanol, and hydrocarbons (toluene, xylene).

  Apply these coating compositions to the surface of the transparent support with a dry film thickness of 0.1 to 10 μm using a gravure coater, dip coater, reverse coater, wire bar coater, die coater, spray coating, ink jet coating or the like. It is more preferable to apply at 0.3 to 5 μm, and particularly preferable to apply at 0.3 to 3 μm. If it is this range, it will prevent that the cellulose ester from a transparent support body, an additive, etc. elute to an optically anisotropic layer, will cause alignment inhibition, and is preferable from a viewpoint of productivity and thin film formation.

  10-150 degreeC is preferable and, as for the drying temperature after intermediate | middle layer application | coating, More preferably, it is 40-120 degreeC. The means for drying is not particularly limited and can be generally performed with hot air, infrared rays, a heating roll, microwave, or the like, but is preferably performed with hot air from the viewpoint of simplicity.

  If the temperature is too low, drying takes time and productivity is lowered. If it is too high, film thickness unevenness tends to occur, and if the intermediate layer has film thickness unevenness, film thickness unevenness tends to occur in the optically anisotropic layer. Unevenness in the thickness of the optically anisotropic layer becomes retardation as it is, which is not preferable because the display performance of the panel is deteriorated. The drying time is preferably 5 to 600 seconds, more preferably 5 to 200 seconds, still more preferably 5 to 60 seconds. If it is the said range, drying will fully be performed and productivity will be high. In the case of drying with hot air, the wind is preferably weak. When the wind is strong, film thickness unevenness may occur.

As a light source for curing the intermediate layer forming composition by a photocuring reaction to form a cured film layer, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 30 to 300 mJ / cm ² .

The intermediate layer is preferably irradiated with ultraviolet rays during or after coating and drying, and the irradiation time for obtaining the necessary actinic radiation dose is preferably about 0.1 second to 1 minute, and the ultraviolet curable resin is cured. From the viewpoint of efficiency or work efficiency, 0.1 to 10 seconds is more preferable. The illuminance of these active ray irradiators is preferably 50 to 150 mW / m ² .

  Moreover, when irradiating an ultraviolet-ray, it is preferable to apply | coat tension | tensile_strength in the conveyance direction of a film, and the tension | tensile_strength to provide is preferable 30-300 N / m. The method for applying tension is not particularly limited, and tension may be applied in the transport direction on the back roll.

  In the method for producing an optical compensation film of the present invention, it is preferable that an intermediate layer composition is applied, dried, and semi-cured by ultraviolet irradiation to form an intermediate layer, and an optically anisotropic layer is formed thereon.

  In the present invention, “semi-cured” means that the intermediate layer is irradiated with ultraviolet rays so that the gel fraction measured by the following measurement is 30 to 80 mass%. When the gel fraction of the semi-cured intermediate layer is less than 30% by mass, the degree of crosslinking is insufficient, resulting in poor solvent resistance, and the semi-cured intermediate layer may be dissolved when forming the optically anisotropic layer There is. On the other hand, if the gel fraction exceeds 80% by mass, crosslinking is excessive, the film is cured too much, and the adhesiveness at the interface with the optically anisotropic layer is lowered, which is not preferable. The amount of ultraviolet irradiation varies depending on the type of urethane acrylate oligomer or acrylate oligomer composition to be used, but it is preferable to adjust the amount within the above-mentioned range of irradiation amount. The amount of ultraviolet irradiation is UVC (250-260 nm), UVB (280-320 nm), UVA (320-390 nm), and UVV (395-445 nm) measured with an ultraviolet light amount measuring device (UV Power Pack manufactured by EIT). The total amount of irradiation light.

<Gel fraction>
About 0.1 g of the semi-cured intermediate layer was taken and weighed to measure the mass (W1). Next, this was wrapped in a microporous tetrafluoroethylene membrane (membrane mass W2), immersed in about 50 ml of ethyl acetate for 7 days, and then the soluble component was extracted. This was dried and the total mass (W3) was measured. From these measured values, the gel fraction (mass%) of the semi-cured intermediate layer was determined by the following formula.

Gel fraction (mass%) = {(W3-W2) / W1} × 100
(Optically anisotropic layer)
The optical compensation film of the present invention is obtained by applying liquid crystal (or a liquid crystal solution) on an intermediate layer, drying and heat treatment (also referred to as alignment treatment), fixing the liquid crystal alignment by ultraviolet curing or thermal polymerization, and the like. It is characterized by having an optically anisotropic layer made of vertically aligned rod-like liquid crystals.

  The term “vertical alignment” as used herein refers to an optical compensation film having an optically anisotropic layer in a crossed Nicol polarizer when evaluated using a polarizing microscope in order to evaluate the optical retardation of the obtained optical anisotropy. A material that appears black when sandwiched between them and appears white when an optical compensation film having an optically anisotropic layer is tilted between crossed Nicol polarizers is defined as being vertically aligned.

  The optically anisotropic layer according to the present invention is preferably an optically anisotropic layer composed of substantially vertically aligned rod-like liquid crystals having retardation Ro in the range of 0 to 10 nm and Rt in the range of −100 to −400 nm. Further, Ro is more preferably in the range of 0 to 5 nm. In order to set the optically anisotropic layer in the above range, the thickness of the optically anisotropic layer is controlled, the temperature during UV curing, the tilt angle control, and the pretilt angle at the support / air interface are controlled. It is preferable.

  The optically anisotropic layer is formed by curing a liquid crystal material capable of forming a liquid crystal phase at a predetermined temperature with a predetermined liquid crystal regularity. The upper limit of the temperature showing the liquid crystal phase is not particularly limited as long as the cellulose ester film of the base material is not damaged. Specifically, a temperature of 120 ° C. or lower is preferable from the viewpoint of easy control of process temperature and maintenance of dimensional accuracy, and a liquid crystal material that becomes a liquid crystal phase at a temperature of 100 ° C. or lower is preferably used. On the other hand, the lower limit of the temperature showing the liquid crystal phase can be said to be a temperature at which the liquid crystal material can maintain the alignment state when used as a phase difference plate.

  As the liquid crystal material used for the optically anisotropic layer of the present invention, a polymerizable liquid crystal material is preferably used. The polymerizable liquid crystal material can be used by being polymerized by irradiating with predetermined actinic radiation. Since the alignment state is fixed in the polymerized state, the liquid crystal phase is used when the polymerizable liquid crystal material is used. The lower limit of the temperature is not particularly limited.

  As the polymerizable liquid crystal material, any of a polymerizable liquid crystal monomer, a polymerizable liquid crystal oligomer, and a polymerizable liquid crystal polymer can be used, and they can also be mixed with each other. Since the polymerizable liquid crystal material can fix the alignment state, the alignment of the liquid crystal can be easily performed at a low temperature, and the alignment state is fixed at the time of use. Can be used regardless of the usage conditions.

  Of the above, a polymerizable liquid crystal monomer is particularly preferably used as the polymerizable liquid crystal material. This is because the polymerizable liquid crystal monomer can be aligned at a lower temperature than the polymerizable liquid crystal oligomer and the polymerizable liquid crystal polymer and has high sensitivity at the time of alignment, so that it can be easily aligned.

  Specific examples of the polymerizable liquid crystal monomer include a rod-like liquid crystal compound (a) represented by the following general formula (4) and a rod-like liquid crystal compound (b) represented by the following general formula (5). be able to. As the compound (a), two or more compounds included in the general formula (4) can be mixed and used. Similarly, the compound (b) is included in the general formula (5). Two or more kinds of compounds may be mixed and used. In addition, one or more compounds (a) and one or more compounds may be used in combination.

In the general formula (4) representing the compound (a), R ¹ and R ² each represent hydrogen or a methyl group, but R ¹ and R ² are both hydrogen due to the wide temperature range showing the liquid crystal phase. preferable. X may be hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, or a nitro group, but is preferably chlorine or a methyl group. Moreover, a and b which show the chain length of the alkylene group which is a spacer with the (meth) acryloyloxy group of both ends of the molecular chain of a compound (a), and an aromatic ring are respectively arbitrary integers in the range of 2-12. Although it can take, it is preferable that it is the range of 4-10, and it is more preferable that it is the range of 6-9. The compound of the general formula (4) in which a = b = 0 is poor in stability, easily subjected to hydrolysis, and the compound itself has high crystallinity. In addition, the compound of the general formula (4) in which a and b are each 13 or more has a low isotropic transition temperature (TI). For this reason, both of these compounds are not preferred because the temperature range showing liquid crystallinity is narrow.

  Compound (a) can be synthesized by any method. For example, the compound (a) in which X is a methyl group can be obtained by an esterification reaction of 1 equivalent of methylhydroquinone and 2 equivalents of 4- (m- (meth) acryloyloxyalkoxy) benzoic acid. In the esterification reaction, the benzoic acid is usually activated with an acid chloride or a sulfonic anhydride, and this is reacted with methylhydroquinone. In addition, a carboxylic acid unit and methylhydroquinone can be reacted directly using a condensing agent such as DCC (dicyclohexylcarbodiimide). As other methods, esterification reaction of 1 equivalent of methylhydroquinone and 2 equivalents of 4- (m-benzyloxyalkoxy) benzoic acid is first performed, and then the resulting ester is debenzylated by hydrogenation reaction or the like. Then, the compound (a) can also be synthesized by a method in which the molecular terminal is acryloylated. When performing esterification reaction of methylhydroquinone and 4- (m-benzyloxyalkoxy) benzoic acid, methylhydroquinone is introduced into diacetate and then reacted with the above benzoic acid in a molten state to obtain an ester directly. It is also possible. The compound (a) in the case where X in the general formula (4) is not a methyl group can also be obtained by performing the same reaction as above using hydroquinone having a corresponding substituent instead of methylhydroquinone.

In the general formula (5) representing the compound (b), R ³ represents hydrogen or a methyl group, but R ³ is preferably hydrogen because of the wide temperature range showing the liquid crystal phase. As for c indicating the chain length of the alkylene group, the compound (b) having this value of 2 to 12 does not exhibit liquid crystallinity. However, in consideration of compatibility with the compound (a) having liquid crystallinity, c is preferably in the range of 4 to 10, and more preferably in the range of 6 to 9. Compound (b) can also be synthesized by an arbitrary method. For example, compound (b) can be synthesized by esterification reaction of 1 equivalent of 4-cyanophenol and 1 equivalent of 4- (n- (meth) acryloyloxyalkoxy) benzoic acid. b) can be synthesized. In the esterification reaction, as in the case of synthesizing the compound (a), the benzoic acid is generally activated with an acid chloride or a sulfonic anhydride, and this is reacted with 4-cyanophenol. Moreover, you may make the said benzoic acid and 4-cyanophenol react using condensing agents, such as DCC (dicyclohexyl carbodiimide).

  In addition to the above, in the present invention, a polymerizable liquid crystal oligomer, a polymerizable liquid crystal polymer, or the like can be used. As such a polymerizable liquid crystal oligomer and a polymerizable liquid crystal polymer, those conventionally proposed can be appropriately selected and used.

  In the present invention, a photopolymerization initiator may be used as necessary in addition to the polymerizable liquid crystal material. When polymerizing a polymerizable liquid crystal material by electron beam irradiation, a photopolymerization initiator may not be necessary. However, in the case of curing by, for example, ultraviolet (UV) irradiation, which is generally used, photopolymerization is usually performed. An initiator is used to promote polymerization.

  As photopolymerization initiators, benzyl (also called bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-benzoyl-4'-methyldiphenyl sulfide, benzylmethyl ketal, dimethylamino Methylbenzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3′-dimethyl-4-methoxybenzophenone, methylobenzoylformate, 2-methyl-1- (4 -(Methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4-dodecylphenyl) -2- Droxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2- Examples include methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, or 1-chloro-4-propoxythioxanthone. it can. In general, the addition amount of the photopolymerization initiator is preferably 0.01% to 20%, more preferably 0.1% to 10%, and still more preferably 0.5% to 5%. Can be added to the polymerizable liquid crystal material of the present invention. In addition to the photopolymerization initiator, a sensitizer can be added as long as the object of the present invention is not impaired.

  The film thickness of the optically anisotropic layer in the present invention is preferably in the range of 0.1 μm to 20 μm, and more preferably in the range of 0.2 to 10 μm. When the optically anisotropic layer of the present invention is thicker than the above range, an optical anisotropy more than necessary occurs, and when it is thinner than the above range, a predetermined optical anisotropy may not be obtained. Therefore, the film thickness of the optically anisotropic layer may be determined according to the required optical anisotropy.

  The polymerizable liquid crystal material is prepared by using a composition for forming an optically anisotropic layer by blending a photopolymerization initiator, a sensitizer and the like as required, and applying the composition onto an intermediate layer to form an optically anisotropic layer. Form. In the present invention, an optically anisotropic layer is formed by applying a solvent to the intermediate layer using a coating composition in which other components are dissolved, and removing the solvent. It is preferable to form a conductive layer.

  The solvent is not particularly limited as long as it is a solvent capable of dissolving the above-described polymerizable liquid crystal material and the like and does not deteriorate the properties of the cellulose ester film or the intermediate layer. Specifically, Hydrocarbons such as benzene, toluene, xylene, n-butylbenzene, diethylbenzene, tetralin; ethers such as methoxybenzene, 1,2-dimethoxybenzene, diethylene glycol dimethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, or 2 Ketones such as 1,4-pentanedione; ethyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, or γ-butyne Esters such as lactones; Amide solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide, or dimethylacetamide; chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, tritrichloroethylene, tetrachloroethylene, chlorobenzene, Or halogen solvents such as orthodichlorobenzene; alcohols such as t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol, hexylene glycol, ethylene glycol monomethyl ether, ethyl cellosolve, or butyl cellosolve One or more of phenols such as phenol and parachlorophenol can be used.

  If only a single type of solvent is used, the solubility of the polymerizable liquid crystal material or the like may be insufficient, or the substrate may be eroded as described above. However, this inconvenience can be avoided by using a mixture of two or more solvents. Of the above-mentioned solvents, preferred as a single solvent are a hydrocarbon solvent and a glycol monoether acetate solvent, and a preferred mixed solvent is a mixed system of ethers or ketones and glycols. It is. The concentration of the solution depends on the solubility of the polymerizable liquid crystal material and the like and the film thickness of the optically anisotropic layer to be produced, but cannot be defined unconditionally, but is usually preferably 1% to 60%, more preferably It is adjusted in the range of 3% to 40%.

Compounds other than those described above can be added to the composition for forming an optically anisotropic layer used in the present invention within a range not impairing the object of the present invention. Examples of compounds that can be added include polyester (meth) acrylate obtained by reacting (meth) acrylic acid with a polyester prepolymer obtained by condensing polyhydric alcohol and monobasic acid or polybasic acid; A polyurethane (meth) acrylate obtained by reacting a compound having two isocyanate groups with each other and then reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak Type epoxy resin, polycarboxylic acid polyglycidyl ester, polyol polyglycidyl ether, aliphatic or cycloaliphatic epoxy resin, amine epoxy resin, triphenolmethane type epoxy resin, dihydroxybenzene type epoxy resin and the like (meth) Ak Photopolymerizable compounds such as epoxy (meth) acrylate obtained by reacting le acid, or a photopolymerizable liquid crystal compound, and the like having an acrylic group or methacrylic group. The amount of these compounds added to the composition for forming an optically anisotropic layer of the present invention is selected within a range that does not impair the object of the present invention, and in general, the composition for forming an optically anisotropic layer of the present invention. Is preferably 40% or less, more preferably 20% or less. Addition of these compounds improves the curability of the liquid crystal material in the present invention, increases the mechanical strength of the resulting optically anisotropic layer, and improves its stability.

  In addition, a surfactant or the like can be added to the composition for forming an optically anisotropic layer containing a solvent in order to facilitate the process. Examples of surfactants that can be added include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides, polyamine derivatives, etc .; polyoxyethylene-polyoxypropylene condensates, primary or secondary Alcohol ethoxylate, alkylphenol ethoxylate, polyethylene glycol and its ester, sodium lauryl sulfate, ammonium lauryl sulfate, amines of lauryl sulfate, alkyl-substituted aromatic sulfonate, alkyl phosphate, aliphatic or aromatic sulfonic acid formalin condensate, etc. Anionic surfactants; amphoteric surfactants such as laurylamidopropylbetaine and laurylaminoacetic acid betaine; nonionic interfaces such as polyethylene glycol fatty acid esters and polyoxyethylene alkylamine Perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl trimethyl ammonium salt, perfluoroalkyl group / hydrophilic group-containing oligomer, perfluoroalkyl / lipophilic group Fluorine-based surfactants such as oligomeric perfluoroalkyl group-containing urethanes may be mentioned. The amount of surfactant added depends on the type of surfactant, the type of liquid crystal material, the type of solvent, and the type of alignment film to which the solution is applied, but usually 10 ppm of the polymerizable liquid crystal material contained in the solution. -10% is preferable, more preferably 100 ppm to 5%, and still more preferably 0.1 to 1%.

  Examples of the method for applying the composition for forming an optically anisotropic layer include spin coating, roll coating, printing, dipping and lifting, die coating, casting, bar coating, blade coating, spray coating, and gravure. Examples thereof include a coating method, a reverse coating method, an extrusion coating method, and an ink jet method. The method for removing the solvent after applying the composition for forming an optically anisotropic layer is performed, for example, by air drying, heat removal, or removal under reduced pressure, or a combination thereof. By removing the solvent, an optically anisotropic layer is formed.

  In the step of curing the polymerizable liquid crystal material, energy for curing the polymerizable liquid crystal material is given, and thermal energy may be used, but it is usually performed by irradiation with ionizing radiation capable of causing polymerization. If necessary, a polymerization initiator may be contained in the polymerizable liquid crystal material. The ionizing radiation is not particularly limited as long as it is a radiation capable of polymerizing the polymerizable liquid crystal material, but usually ultraviolet light or visible light is used from the viewpoint of the ease of the apparatus, and the wavelength. Is preferably from 150 to 500 nm, more preferably from 250 to 450 nm, and even more preferably from 300 to 400 nm.

  In the present invention, a method of performing radical polymerization by irradiating ultraviolet rays (UV) as actinic radiation and generating radicals from the polymerization initiator with ultraviolet rays is preferable. Since the method using UV as the actinic radiation is an already established technique, it can be easily applied to the present invention including the polymerization initiator to be used.

  As a light source for irradiating ultraviolet rays, a low-pressure mercury lamp (sterilization lamp, fluorescent chemical lamp, black light), a high-pressure discharge lamp (high-pressure mercury lamp, metal halide lamp), or a short arc discharge lamp (ultra-high-pressure mercury lamp, xenon) Lamp, mercury xenon lamp) and the like. In particular, the use of metal halide lamps, xenon lamps, high-pressure mercury lamps, etc. is recommended. The irradiation intensity may be appropriately adjusted depending on the composition of the polymerizable liquid crystal material forming the optically anisotropic layer and the amount of the photopolymerization initiator.

  The alignment fixing step by irradiation with actinic radiation may be performed at the processing temperature in the step of forming the optically anisotropic layer forming layer described above, that is, a temperature condition in which the polymerizable liquid crystal material becomes a liquid crystal phase. The temperature may be lower than the temperature at which The polymerizable liquid crystal material once in a liquid crystal phase does not suddenly disturb the alignment state even if the temperature is lowered thereafter.

(Transparent support)
As a transparent support used in the present invention, it is preferable that it is easy to produce and optically transparent.

  The term “transparent” as used in the present invention means that the visible light transmittance is 60% or more, preferably 80% or more, and particularly preferably 90% or more.

  Although it will not specifically limit if it has said property, For example, cellulose ester-type films, such as a cellulose diacetate film, a cellulose triacetate film, a cellulose acetate propionate film, a cellulose acetate butyrate film, a polyester-type film, a polycarbonate Film, polyarylate film, polysulfone (including polyethersulfone) film, polyester film such as polyethylene terephthalate and polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol Film, syndiotactic polystyrene film, polycarbonate film, nor Runen resin film, a polymethylpentene film, a polyether ketone film, polyether ketone imide film, a polyamide film, a fluororesin film, a nylon film, polymethyl methacrylate film, may be mentioned acrylic film or a glass plate or the like.

  In the present invention, a cellulose ester film satisfying the above formulas 4 to 6 is particularly preferable for obtaining the effects of the present invention.

  As the cellulose ester used in the cellulose ester film, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and cellulose acetate phthalate are preferable, and among them, cellulose acetate and cellulose acetate propionate are preferably used. Commercially available cellulose ester films can also be used, and specific examples thereof include, for example, Konica Minoltak KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC12UR, KC4FR, KC8UY Minolta Opto Co., Ltd.) is preferably used from the viewpoints of production, cost, transparency, adhesion and the like. These films may be films produced by melt casting film formation or films produced by solution casting film formation.

<Cellulose ester>
The cellulose ester used in the present invention will be described in detail.

  The cellulose ester used in the present invention is preferably an aliphatic carboxylic acid ester having about 2 to 22 carbon atoms, an aromatic carboxylic acid ester, or a mixed ester of an aliphatic carboxylic acid ester and an aromatic carboxylic acid ester. A lower fatty acid ester is preferred. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. Specifically, it is described in cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate phthalate, etc., JP-A Nos. 10-45804, 8-231761, U.S. Pat. No. 2,319,052, and the like. And mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate. Among the above descriptions, the lower fatty acid ester of cellulose particularly preferably used is cellulose acetate propionate.

  The cellulose ester has an acyl group having 2 to 22 carbon atoms as a substituent, and when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group is Y, the cellulose that simultaneously satisfies the following formulas 7 and 8: An ester is preferred.

Formula 7 2.00 ≦ X + Y ≦ 2.60
Formula 8 0.10 ≦ Y ≦ 1.50
Among them, 2.30 ≦ X + Y ≦ 2.55 is preferable, and 2.40 ≦ X + Y ≦ 2.55 is more preferable. Further, 0.50 ≦ Y ≦ 1.30 is preferable, and 0.70 ≦ Y ≦ 1.00 is more preferable.

  The portion not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by known methods. Moreover, these acyl group substitution degrees can be measured according to the method prescribed | regulated to ASTM-D817-96.

  As the cellulose ester, a cellulose ester synthesized using cotton linter, wood pulp, kenaf or the like as a raw material can be used alone or in combination. In particular, it is preferable to use a cotton linter (hereinafter sometimes simply referred to as a linter) or a cellulose ester synthesized from wood pulp alone or in combination.

  Moreover, the cellulose ester obtained from these can be mixed and used in arbitrary ratios, respectively. These cellulose esters are prepared by using an organic acid such as acetic acid or an organic solvent such as methylene chloride when sulfuric acid is used as the acylating agent (acetic anhydride, propionic anhydride, butyric anhydride). It can obtain by making it react by a conventional method using a protic catalyst like.

  In the case of acetylcellulose, it is necessary to extend the time for the acetylation reaction in order to increase the acetylation rate. However, if the reaction time is too long, the decomposition proceeds at the same time, and the polymer chain is broken and the acetyl group is decomposed, resulting in undesirable results. Therefore, it is necessary to set the reaction time within a certain range in order to increase the degree of acetylation and suppress decomposition to some extent. It is not appropriate to define the reaction time because the reaction conditions are various and greatly change depending on the reaction apparatus, equipment and other conditions. As the decomposition of the polymer progresses, the molecular weight distribution becomes wider. Therefore, in the case of cellulose ester, the degree of decomposition can be defined by the value of weight average molecular weight (Mw) / number average molecular weight (Mn) that is usually used. That is, in the process of acetylation of cellulose triacetate, the weight average molecular weight is used as one index of the reaction degree for allowing the acetylation reaction to be carried out for a sufficient time for acetylation without being too long and being decomposed too much. The value of (Mw) / number average molecular weight (Mn) can be used.

  The ratio Mw / Mn of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the cellulose ester used in the present invention is preferably 1.4 to 3.0. In addition, in this invention, it is preferable that a cellulose-ester film contains the cellulose ester whose value of Mw / Mn is 1.4-3.0 as a material. In the process of synthesizing cellulose ester, it is difficult to make it less than 1.4, and cellulose ester having a uniform molecular weight can be obtained by fractionation by gel filtration or the like. However, this method is very expensive. Moreover, it is preferable that it is 3.0 or less because the flatness is easily maintained. In addition, More preferably, it is 1.7-2.2.

The molecular weight of the cellulose ester used in the present invention is preferably a number average molecular weight (Mn) of 80,000 to 200,000. More preferred are 100,000 to 200,000, particularly preferably 150,000 to 200,000.

  The average molecular weight and molecular weight distribution of the cellulose ester can be measured by a known method using high performance liquid chromatography. Using this, the number average molecular weight and the weight average molecular weight can be calculated, and the ratio (Mw / Mn) can be calculated.

The measurement conditions are as follows.
Solvent: Methylene chloride column: Shodex K806, K805, K803G (used by connecting 3 products manufactured by Showa Denko KK)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Mw = 100000-500 calibration curves with 13 samples were used. It is preferable to obtain 13 samples at approximately equal intervals.

  The method for producing cellulose ester can be obtained by the method described in JP-A-10-45804.

  Cellulose esters are also affected by trace metal components in cellulose esters. These are considered to be related to water used in the production process, but it is preferable that there are few components that can become insoluble nuclei, and metal ions such as iron, calcium, and magnesium contain organic acidic groups. Insoluble matter may be formed by salt formation with a polymer degradation product or the like that may be present, and it is preferable that the amount is small. The iron (Fe) component is preferably 1 ppm or less. About calcium (Ca) component, it is contained in a lot of ground water and river water, etc., and it becomes hard water, and it is unsuitable as drinking water. Coordination compounds with ligands, that is, complexes are easily formed, and scum (insoluble starch, turbidity) derived from many insoluble calcium is formed.

  The calcium (Ca) component is 60 ppm or less, preferably 0 to 30 ppm. The magnesium (Mg) component is preferably in the range of 0 to 70 ppm, particularly preferably 0 to 20 ppm, since too much will cause insoluble matter. Metal components such as iron (Fe) content, calcium (Ca) content, magnesium (Mg) content, etc. are pre-processed by completely digesting cellulose ester with micro digest wet cracking equipment (sulfuric acid decomposition) and alkali melting. After performing, it can obtain | require by performing an analysis using ICP-AES (inductively coupled plasma optical emission spectrometry).

  The cellulose ester film used in the present invention preferably has a refractive index of 1.45 to 1.60 at 550 nm. As a method for measuring the refractive index of the film, an Abbe refractometer is used, and measurement is performed based on Japanese Industrial Standard JIS K 7105.

<Additive>
The cellulose ester film can contain additives such as a plasticizer, an ultraviolet absorber, an antioxidant, and a matting agent.

  The present invention preferably contains the following plasticizer. Examples of plasticizers include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, glycolate plasticizers, citrate ester plasticizers, and polyesters. A plasticizer, a polyhydric alcohol ester plasticizer, and the like can be preferably used.

  For phosphate plasticizers, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. For phthalate ester plasticizers, diethyl phthalate, dimethoxy For trimellitic acid plasticizers such as ethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, tributyl trimellitate, triphenyl trimellitate, triethyl For pyromellitic acid ester plasticizers such as trimellitate, tetrabutylpyromellitate, In the case of glycolate plasticizers such as lupyromelitate and tetraethylpyromellitate, triacetin, tributyrin, ethylphthalylethyl glycolate, methylphthalylethyl glycolate, butylphthalylbutyl glycolate, etc. Citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate and the like can be preferably used. Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters.

  As the polyester plasticizer, a copolymer of a dibasic acid and a glycol such as an aliphatic dibasic acid, an alicyclic dibasic acid, or an aromatic dibasic acid can be used. The aliphatic dibasic acid is not particularly limited, and adipic acid, sebacic acid, phthalic acid, terephthalic acid, 1,4-cyclohexyl dicarboxylic acid, and the like can be used. As glycol, ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol and the like can be used. These dibasic acids and glycols may be used alone or in combination of two or more.

  The polyhydric alcohol ester plasticizer comprises an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid. Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these. Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, 2-n-butyl-2-ethyl- 1,3-propanediol, galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol, and the like can be raised. In particular, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable. There is no restriction | limiting in particular as monocarboxylic acid used for polyhydric alcohol ester, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto. As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10. When acetic acid is contained, the compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid. Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid, Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid, undecylenic acid, olein Unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid can be raised. Examples of preferable alicyclic monocarboxylic acid include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof. Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid. Aromatic monocarboxylic acids or derivatives thereof can be raised. Particularly preferred is benzoic acid. The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably in the range of 300 to 1500, and more preferably in the range of 350 to 750. The larger one is preferable in terms of improving the retention, and the smaller one is preferable in terms of moisture permeability and compatibility with the cellulose ester.

  The carboxylic acid used in the polyhydric alcohol ester used in the present invention may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified with carboxylic acid, or a part of the OH groups may be left as they are.

  These plasticizers are preferably used alone or in combination.

  The amount of these plasticizers used is preferably from 1 to 20% by mass, particularly preferably from 3 to 13% by mass, based on the cellulose ester, in terms of film performance, processability and the like.

  The ultraviolet absorber that can be used in the present invention aims to improve durability by absorbing ultraviolet rays of 400 nm or less, and preferably has a transmittance of 10% or less at a wavelength of 370 nm. More preferably, it is 5% or less, and further preferably 2% or less.

  Although the ultraviolet absorber used in the present invention is not particularly limited, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic powders Examples include the body. It is good also as a polymer type ultraviolet absorber.

  It is also preferable to use fine particles in the cellulose ester film used in the present invention. As the fine particles, both inorganic compounds and organic compounds can be used. Examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate And calcium phosphate. Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable.

  The average primary particle size of the fine particles is preferably 5 to 50 nm, and more preferably 7 to 20 nm. These are preferably contained mainly as secondary aggregates having a particle size of 0.05 to 0.3 μm. The content of these fine particles in the cellulose ester film is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.5% by mass. In the case of a cellulose ester film having a multilayer structure by the co-casting method, it is preferable to contain fine particles of this addition amount on the surface.

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

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

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

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of reducing the friction coefficient while keeping the turbidity of the cellulose ester film low.

<Method for producing cellulose ester film>
Next, the manufacturing method of the cellulose ester film used for this invention is demonstrated.

  The cellulose ester film used in the present invention is preferably a cellulose ester film produced by a solution casting method or melt casting.

  The cellulose ester film used in the present invention was produced by dissolving a cellulose ester and an additive in a solvent to prepare a dope, casting a dope onto an endless metal support, and casting the dope. The step of drying the dope as a web, the step of peeling from the metal support, the step of stretching or maintaining the width, the step of further drying, and the step of winding up the finished film are performed.

  The process for preparing the dope will be described. The concentration of cellulose ester in the dope is preferably higher because the drying load after casting on the metal support can be reduced. However, if the concentration of cellulose ester is too high, the load during filtration increases and the filtration accuracy is poor. Become. As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%.

  The solvent used in the dope may be used alone or in combination of two or more, but it is preferable to use a mixture of a good solvent and a poor solvent of cellulose ester in terms of production efficiency, and there are many good solvents. This is preferable from the viewpoint of the solubility of the cellulose ester.

  The preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent. With a good solvent and a poor solvent, what dissolve | melts the cellulose ester to be used independently is defined as a good solvent, and what poorly swells or does not melt | dissolve is defined as a poor solvent.

  Therefore, depending on the average acetylation degree (acetyl group substitution degree) of the cellulose ester, the good solvent and the poor solvent change. For example, when acetone is used as the solvent, the cellulose ester acetate (acetyl group substitution degree 2.4), cellulose Acetate propionate is a good solvent, and cellulose acetate (acetyl group substitution degree 2.8) is a poor solvent.

  Although the good solvent used for this invention is not specifically limited, Organic halogen compounds, such as a methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate, etc. are mentioned. Particularly preferred is methylene chloride or methyl acetate.

  Moreover, although the poor solvent used for this invention is not specifically limited, For example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone, etc. are used preferably. Moreover, it is preferable that 0.01-2 mass% of water contains in dope. Moreover, the solvent used for melt | dissolution of a cellulose ester collect | recovers the solvent removed from the film by drying at the film-forming process, and uses this again.

  A general method can be used as a dissolution method of the cellulose ester when preparing the dope described above. When heating and pressurization are combined, it is possible to heat above the boiling point at normal pressure. It is preferable to stir and dissolve while heating at a temperature that is equal to or higher than the boiling point of the solvent at normal pressure and does not boil under pressure, in order to prevent the formation of massive undissolved materials called gels and mamacos. Moreover, after mixing a cellulose ester with a poor solvent and making it wet or swell, the method of adding a good solvent and melt | dissolving is also used preferably.

  The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

  The heating temperature with the addition of a solvent is preferably higher from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates. A preferable heating temperature is 45 to 120 ° C, more preferably 60 to 110 ° C, and still more preferably 70 ° C to 105 ° C. The pressure is adjusted so that the solvent does not boil at the set temperature.

  Alternatively, a cooling dissolution method is also preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

  Next, this cellulose ester solution is filtered using a suitable filter medium such as filter paper. As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters and the like, but there is a problem that the filter medium is likely to be clogged if the absolute filtration accuracy is too small. For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with 0.001 to 0.008 mm is more preferable, and a filter medium with 0.003 to 0.006 mm is still more preferable.

  There are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, plastic filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel do not drop off fibers. preferable. It is preferable to remove and reduce impurities, particularly bright spot foreign matter, contained in the raw material cellulose ester by filtration.

The bright spot foreign matter was placed in a crossed Nicols state with two polarizing plates, a rolled cellulose ester was placed between them, and light was applied from the side of one polarizing plate, and observed from the side of the other polarizing plate. It is a point (foreign matter) that light from the opposite side appears to leak sometimes, and the number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm ² or less. More preferably, it is 100 pieces / cm < ² > or less, More preferably, it is 50 pieces / m < ² > or less, More preferably, it is 0-10 pieces / cm < ² > or less. Further, it is preferable that the number of bright spots of 0.01 mm or less is small.

  The dope can be filtered by a normal method, but the method of filtering while heating at a temperature not lower than the boiling point of the solvent at normal pressure and in a range where the solvent does not boil under pressure is the filtration pressure before and after filtration. The increase in the difference (referred to as differential pressure) is small and preferable. A preferred temperature is 45 to 120 ° C, more preferably 45 to 70 ° C, and still more preferably 45 to 55 ° C.

  A smaller filtration pressure is preferred. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

  Here, the dope casting will be described.

  The metal support in the casting (casting) step preferably has a mirror-finished surface. As the metal support, a stainless steel belt or a drum whose surface is plated with a casting is preferably used. The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is −50 ° C. to a temperature lower than the boiling point of the solvent, and a higher temperature is preferable because the web can be dried faster. May deteriorate. A preferable support body temperature is 0-40 degreeC, and 5-30 degreeC is still more preferable.

  Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent.

  The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short. When warm air is used, wind at a temperature higher than the target temperature may be used.

  In order for the roll cellulose ester to exhibit good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. %, Particularly preferably 20 to 30% by mass or 70 to 120% by mass.

  In the drying step of the roll cellulose ester, the web is peeled off from the metal support and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less. Particularly preferably, it is 0 to 0.01% by mass or less.

  In the present invention, the residual solvent amount can be expressed by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Here, M is a mass at an arbitrary time point of the web, and is a mass measured by the following gas chromatography. N is a mass when the M is dried at 110 ° C. for 3 hours. The measurement is performed by gas chromatography connected to a headspace sampler. In the present invention, gas chromatography 5890 type SERISII and headspace sampler HP7694 type manufactured by Hewlett-Packard Company were used and the measurement was performed under the following measurement conditions.

Headspace sampler heating conditions: 120 ° C, 20 minutes GC introduction temperature: 150 ° C
Temperature rise: 40 ° C, hold for 5 minutes → 100 ° C (8 ° C / min)
Column: J-W DB-WAX (inner diameter 0.32 mm, length 30 m).

  In the film drying process, generally, a roll drying method (a method in which a plurality of rolls arranged on the upper and lower sides are alternately passed through and dried) or a method of drying while transporting the web by a tenter method is adopted.

  In order to produce the cellulose ester film according to the present invention, the web is stretched in the transport direction (= long direction) where the amount of residual solvent of the web immediately after peeling from the metal support is large, and both ends of the web are gripped with clips or the like. It is preferable to stretch in the width direction by the tenter method.

  The stretching operation may be performed in multiple stages, and biaxial stretching is preferably performed in the casting direction and the width direction. Also, when biaxial stretching is performed, simultaneous biaxial stretching may be performed or may be performed stepwise. In this case, stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any one of the stages. Is also possible.

  In addition, the “stretch direction” in the present invention is usually used to mean a direction in which a stretching stress is directly applied when performing a stretching operation. In some cases, it is used in the sense of the one having a higher draw ratio (that is, the direction usually serving as the slow axis).

  It is preferable that the retardation value of the cellulose ester film used for this invention satisfy | fills following formula 4-6.

Formula 4 30 ≦ Ro ≦ 115 (nm)
Formula 5 100 ≦ Rt ≦ 250 (nm)
Formula 6 1.6 ≦ Rt / Ro ≦ 4.4
However, said Ro and Rt are the retardation values represented by the following formula | equation.

Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(In the formula, the refractive index in the slow axis direction in the film plane is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, the refractive index in the thickness direction of the film is nz, d is the thickness of the film ( nm).)
The above Ro and Rt were measured for retardation at a wavelength of 590 nm in an environment of 23 ° C. and 55% RH using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments). Then, a value obtained by measuring the average refractive index of the sample with an Abbe refractometer is input to the above formula to obtain values of in-plane retardation Ro and thickness direction retardation Rt.

  In the present invention, in order to obtain the retardation value, the cellulose ester film is preferably controlled by a stretching operation.

  Here, the stretching step important for obtaining a desired retardation value will be described in more detail. The stretching ratio in producing the cellulose ester film of the present invention is preferably 1.01 to 3 times, more preferably 1.1 to 2 times, with respect to the film forming direction or the width direction. . When stretching in the biaxial direction, the side to be stretched at a high magnification is 1.01 to 3 times, preferably 1.1 to 2 times, and the stretching ratio in the other direction is 0.8 to 1.5. The film can be stretched by a factor of preferably 0.9 to 1.2.

  An example of a stretching process (also referred to as a tenter process) for producing the cellulose ester film used in the present invention will be described with reference to FIGS.

  In FIG. 1, step A is a step of gripping the film transported from the film transport step D0 (not shown). In the next step B, the film moves in the width direction (progress of the film) as shown in FIG. In step C, stretching is completed, and the film is conveyed while being gripped.

  It is preferable to provide a slitter for cutting off the end in the film width direction after the film is peeled off and before the start of the process B and / or immediately after the process C. In particular, it is preferable to provide a slitter that cuts off the film edge immediately before the start of the step A. When the same stretching is performed in the width direction, particularly when the film edge is cut off before the start of step B and the condition in which the film edge is not cut is compared, the former is more optically retarded in the width direction of the film. The effect of improving the axial distribution (hereinafter referred to as orientation angle distribution) can be obtained. This is considered to be an effect of suppressing unintended stretching in the longitudinal direction from the peeling with a relatively large amount of residual solvent to the width stretching step B.

  In the tenter process, it is also preferable to intentionally create compartments with different temperatures in order to improve the orientation angle distribution. It is also preferable to provide a neutral zone between different temperature zones so that the zones do not interfere with each other.

  Furthermore, since the cellulose ester film is stretched in the width direction with a good orientation angle distribution, there is a preferable film temperature relative relationship in steps A, B, and C. When the film temperatures at the end points of Steps A, B, and C are Ta ° C., Tb ° C., and Tc ° C., respectively, it is preferable that Ta ≦ Tb−10. Moreover, it is preferable that Tc ≦ Tb. More preferably, Ta ≦ Tb−10 and Tc ≦ Tb.

  The film heating rate in the step B is preferably in the range of 0.5 to 10 ° C./s in order to improve the orientation angle distribution.

  The stretching time in step B is preferably a short time in order to reduce the dimensional change at high temperature and high humidity. However, the minimum required stretching time range is defined from the viewpoint of film uniformity. Specifically, the range is preferably 1 to 10 seconds, and more preferably 4 to 10 seconds. Moreover, the temperature of the process B is 40-180 degreeC, Preferably it is 100-160 degreeC.

In the tenter process, the heat transfer coefficient may be constant or changed. The heat transfer coefficient preferably has a heat transfer coefficient in the range of 41.9 to 419 × 10 ³ J / m ² hr. More preferably, it is the range of 41.9-209.5 * 10 < ³ > J / m < ² > hr, and the range of 41.9-126 * 10 < ³ > J / m < ² > hr is the most preferable.

  In order to improve the dimensional stability at high temperature and high humidity, the stretching speed in the width direction in the step B may be constant or may be changed. The stretching speed is preferably 50 to 500% / min, more preferably 100 to 400% / min, and most preferably 200 to 300% / min.

  In the tenter process, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film, and the temperature distribution in the width direction in the tenter process is preferably within 5 ° C, more preferably within 2 ° C. Preferably, the temperature is within 1 ° C. By reducing the temperature distribution, it can be expected that the temperature distribution in the width of the film is also reduced.

  In step C, it is preferable to relax in the width direction in order to suppress dimensional changes. Specifically, it is preferable to adjust the film width so that it is in the range of 95 to 99.5% with respect to the film width of the previous step.

  After the treatment in the tenter process, it is preferable to further provide a post-drying process (hereinafter referred to as process D1). It is preferable to carry out at 50-160 degreeC. More preferably, it is the range of 80-150 degreeC, Most preferably, it is the range of 110-150 degreeC.

  In step D1, it is preferable that the atmospheric temperature distribution in the width direction of the film is small from the viewpoint of improving the uniformity of the film. It is preferably within 5 ° C, more preferably within 2 ° C, and most preferably within 1 ° C.

  The film transport tension in the step D1 is affected by the physical properties of the dope, the peeling and the residual solvent amount in the step D0, the temperature in the step D1, etc., but is preferably 120 to 200 N / m, and 140 to 200 N / m. Further preferred. 140 to 160 N / m is most preferable.

  A tension cut roll is preferably provided for the purpose of preventing the film from stretching in the transport direction in step D1. After drying, it is preferable to provide a slitter and cut off the end portion before winding to obtain a good winding shape.

  In this invention, when a cellulose-ester film is elongate, it is preferable that the fast axis of a cellulose-ester film corresponds with the conveyance direction. The long PVA polarizer has an absorption axis in the longitudinal direction, and the fast axis of the cellulose ester film applied as a polarizing plate protective film is in the longitudinal direction, so that both can be directly bonded. . This is a preferable configuration from the viewpoint of productivity of the polarizing plate.

  The film thickness of the cellulose ester film according to the present invention is preferably in the range of 20 to 200 μm, more preferably 20 to 100 μm, and particularly preferably 20 to 80 μm.

(Optical characteristics of optical compensation film)
The optical compensation film of the present invention has the effect of realizing the high productivity, the reduction of orientation defects of the optically anisotropic layer, and the high adhesion between the support and the optically anisotropic layer, which are the objects of the present invention, in particular. When applied to an IPS mode (transverse electric field switching mode) type liquid crystal display device and a VA mode type liquid crystal display device, it is possible to reduce a change in tint when the viewing angle is changed. Therefore, the retardation at a wavelength of 590 nm in an environment of 23 ° C. and 55% RH in a state where the cellulose ester film and the optically anisotropic layer are laminated is in a range of Ro: 30 to 105 nm, Rt: −300 to 25 nm. More preferably, Ro is 45 to 95 nm, Rt is -100 to 25 nm, and Rt is particularly preferably -60 to 20 nm.

Further, the laminated film has an optical axis in the same plane, and the wavelength dispersion characteristic defined by the following formulas 9 to 12,
D (Ro) 1: 0.9 to 1.0
D (Ro) 2: −9.5 to 0 nm
D (Rt) 1: 0.3 to 0.9
D (Rt) 2: −100 to −10 nm
It is preferable that

Formula 9: D (Ro) 1 = Ro (630) / Ro (480)
Formula 10: D (Ro) 2 = Ro (630) -Ro (480)
Formula 11: D (Rt) 1 = | Rt (630) / Rt (480) |
Formula 12: D (Rt) 2 = Rt (480) -Rt (630)
(In the formula, Ro (480) and Ro (630) are retardation Ro values at 480 nm and 630 nm, respectively, in an environment of 23 ° C. and 55% RH, and Rt (480) and Rt (630) are retardation Rt at 480 nm and 630 nm, respectively. Represents the value.)
In order to make the optical characteristics of the optical compensation film of the present invention within the above numerical range, in the stretching process of the cellulose ester film, the balance between the stretching temperature and the stretching ratio is precisely controlled, and the stretched portion (such as a tenter clip) is controlled. It is preferable to control independently on both sides of the film. This can be achieved by adjusting the stretching temperature and the stretching ratio with respect to the clip position and the stress of the clip. It is also preferable to control the film thickness of the optically anisotropic layer, the temperature during UV curing, the tilt angle control, and the control of the pretilt angle at the support / air interface. In particular, the film thickness control and the curing temperature have a great influence on the phase difference control.

  Further, as means for controlling the wavelength dispersion, it is preferable that D (Ro) 1 and D (Ro) 2 are appropriately selected from the materials and production methods of the cellulose ester film. Regarding the material, these values can be achieved by changing the substituent (type / substitution degree) of the cellulose ester material. In the case of only an acetyl group, the value increases as the degree of substitution decreases, and tends to decrease as the propionyl group increases. It also varies depending on the additive.

(Polarizer)
The polarizing plate can be produced by a general method. The optical compensation film of the present invention is preferably bonded to at least one surface of a polarizing film prepared by subjecting the back side of the optical compensation film to alkali saponification treatment and immersion drawing in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. The film may be used on the other surface, or another polarizing plate protective film may be used. Commercially available cellulose ester films (for example, Konica Minoltack KC8UX2M, KC4UX2M, KC5UN, KC4UY, KC8UY, KC12UR, KC4UEW, KC8UCR3, KC8UCR4, KC8UCR5, KC4FR-8, KC4FR-8, KC4FR-8, (Made by Co., Ltd.) is also preferably used.

  A polarizing film, which is a main component of a polarizing plate, is an element that transmits only light having a plane of polarization in a certain direction. A typical polarizing film currently known is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed. As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound.

(Display device)
By incorporating the polarizing plate of the present invention into a liquid crystal display device, the liquid crystal display device of the present invention having excellent visibility can be produced. The polarizing plate of the present invention can optimize the viewing angle characteristics of a liquid crystal display device employing various driving methods such as TN, VA, OCB, HAN, and IPS.

  In particular, it is preferably used in VA mode type and IPS mode type LCDs. The liquid crystal display device incorporating the polarizing plate of the present invention has a high contrast even in a large-screen liquid crystal display device having a screen of 30 or more types, particularly 30 to 54 types, and suppresses color change due to viewing angle, for a long time. There is an effect that the eyes are not tired even when watching.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Measurement of retardation>
In the examples, the average refractive index of the film was measured using an Abbe refractometer (4T). Moreover, the thickness of the film was measured using a commercially available micrometer.

  Using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), film retardation measurement at a wavelength of 590 nm was performed under the same environment for 24 hours in an environment of 23 ° C. and 55% RH. went.

  The retardation was calculated using the following formula (i) and formula (ii).

Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(In the formula, the refractive index in the slow axis direction in the film plane is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, the refractive index in the film thickness direction is nz, d is the thickness of the film (nm )
Example 1
<< Preparation of transparent support >>
<Preparation of transparent support A-1>
(Silicon dioxide dispersion)
Aerosil 972V (manufactured by Nippon Aerosil Co., Ltd.) 12 parts by mass (average diameter of primary particles 16 nm, apparent specific gravity 90 g / liter)
88 parts by mass of ethanol or more was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin. The liquid turbidity after dispersion was 200 ppm. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes to prepare a silicon dioxide dispersion dilution.

<Aromatic terminal ester 1>
Into a reaction vessel, 820 parts (5 moles) of phthalic acid, 608 parts (8 moles) of 1,2-propylene glycol, 610 parts (5 moles) of benzoic acid and 0.30 parts of tetraisopropyl titanate as a catalyst are charged all at once. While stirring in an air stream, a reflux condenser was attached to reflux excess monohydric alcohol, and heating was continued at 130 to 250 ° C. until the acid value became 2 or less, and water produced was continuously removed. Next, the distillate is removed under reduced pressure of 6.65 × 10 ³ Pa to 4 × 10 ² Pa or less at 200 to 230 ° C., and then filtered to obtain an aromatic terminal ester 1 having the following properties. Obtained.

Viscosity (25 ° C., mPa · s); 19815
Acid value: 0.4
The acid value refers to the number of milligrams of potassium hydroxide necessary for neutralizing the acid (carboxyl group present at the molecular terminal) contained in 1 g of the sample. The acid value and the hydroxyl value are measured according to JIS K0070.

(Dope solution)
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) 100 parts by mass Trimethylolpropane tribenzoate 5 parts by mass The above aromatic terminal ester 1 5 parts by mass Silicon dioxide Dispersion diluent 10 parts by mass Methylene chloride 430 parts by mass Ethanol 40 parts by mass The above dope composition was put into a sealed container, heated to 70 ° C., and stirred to completely dissolve the cellulose ester to obtain a dope solution. Next, after the dope solution was filtered, the dope solution whose temperature was adjusted to 33 ° C. was fed to the die and uniformly cast with a width of 2.5 m from the die slit onto the stainless steel belt. The cast part of the stainless steel belt was heated from the back with hot water of 37 ° C. After casting, the dope film on the metal support (which is called a web after casting on the stainless steel belt) is dried by applying hot air of 44 ° C., and the residual solvent in the peeling is peeled off at 120 mass%. Then, the web was stretched to a longitudinal stretching ratio of 1.01 times by applying a tension of, and then the end of the web was gripped with a tenter at a residual solvent amount of 24% and a temperature of 135 ° C. It extended | stretched so that it might become the draw ratio of. After stretching, hold for several seconds while maintaining its width, relax the tension in the width direction,
It was dried at 120 ° C. after releasing the width retention. A cellulose ester film having a thickness of 60 μm, a width of 2.5 m, and a length of 5000 m produced as described above was wound around a core.

  As for the retardation of this cellulose ester film, Ro was 70 nm, Rt was 200 nm, and Rt / Ro was 2.86.

<Preparation of transparent support A-2>
Transparent support A-2 was produced in the same manner as transparent support A-1, except that the film thickness was adjusted to 80 μm. As for the retardation of this cellulose ester film, Ro was 90 nm, Rt was 230 nm, and Rt / Ro was 2.56.

<Preparation of transparent support A-3>
(Silicon dioxide dispersion)
Aerosil 972V (manufactured by Nippon Aerosil Co., Ltd.) 12 parts by mass (average diameter of primary particles 16 nm, apparent specific gravity 90 g / liter)
88 parts by mass of ethanol or more was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin. The liquid turbidity after dispersion was 200 ppm. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes to prepare a silicon dioxide dispersion dilution.

(Dope solution)
Cellulose ester (acetyl group substitution degree 2.70, total acyl group substitution degree 2.70)
100 parts by mass Trimethylolpropane tribenzoate 5 parts by mass The above aromatic terminal ester 1 5 parts by mass Silicon dioxide dispersion diluent 10 parts by mass The following retardation adjuster 2 parts by mass Methylene chloride 430 parts by mass Ethanol 40 parts by mass The solution was put into a sealed container, heated to 70 ° C., and while stirring, the cellulose ester was completely dissolved to obtain a dope solution. Next, after the dope solution was filtered, the dope solution whose temperature was adjusted to 33 ° C. was fed to the die and uniformly cast with a width of 2.5 m from the die slit onto the stainless steel belt. The cast part of the stainless steel belt was heated from the back with hot water of 37 ° C. After casting, the dope film on the metal support (which is called a web after casting on the stainless steel belt) is dried by applying hot air of 44 ° C., and the residual solvent in the peeling is peeled off at 120 mass%. Then, the web was stretched to a longitudinal stretching ratio of 1.01 times by applying a tension of, and then the end of the web was gripped with a tenter at a residual solvent amount of 24% and a temperature of 135 ° C., and 1.40 times in the width direction. It extended | stretched so that it might become the draw ratio of. After stretching, the film was held for several seconds while maintaining its width, then the tension in the width direction was relaxed, and the film was dried at 120 ° C. after releasing the width. A cellulose ester film having a thickness of 60 μm, a width of 2.5 m, and a length of 5000 m produced as described above was wound around a core.

  As for the retardation of this cellulose ester film, Ro was 70 nm, Rt was 200 nm, and Rt / Ro was 2.86.

<Preparation of transparent support A-4>
In a nitrogen atmosphere, 500 parts of dehydrated cyclohexane, 1.2 parts of 1-hexene, 0.15 part of dibutyl ether, and 0.30 part of triisobutylaluminum were mixed in a reactor at room temperature, and then kept at 45 ° C. 20 parts of tricyclo [4.3.0.12,5] deca-3,7-diene (dicyclopentadiene, hereinafter abbreviated as DCP), 1,4-methano-1,4,4a, 9a-tetrahydrofluorene ( Hereinafter, a norbornene-based monomer comprising 140 parts of MTF) and 40 parts of 8-methyl-tetracyclo [4.4.0.12, 5.17,10] -dodec-3-ene (hereinafter abbreviated as MTD). The mixture and 40 parts of tungsten hexachloride (0.7% toluene solution) were continuously added over 2 hours for polymerization. To the polymerization solution, 1.06 part of butyl glycidyl ether and 0.52 part of isopropyl alcohol were added to deactivate the polymerization catalyst and stop the polymerization reaction.

  Next, 270 parts of cyclohexane is added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and further 5 parts of a nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) is added as a hydrogenation catalyst. The mixture was heated to 200 ° C. while being pressurized and stirred, and then reacted for 4 hours to obtain a reaction solution containing 20% of a DCP / MTF / MTD ring-opening polymer hydrogenated polymer. After removing the hydrogenation catalyst by filtration, a soft polymer (manufactured by Kuraray; Septon 2002) and an antioxidant (manufactured by Ciba Specialty Chemicals; Irganox 1010) are added and dissolved in the resulting solution. (Both 0.1 parts per 100 parts polymer). Next, cyclohexane and other volatile components, which are solvents, are removed from the solution using a cylindrical concentration dryer (manufactured by Hitachi, Ltd.), the hydrogenated polymer is extruded in a strand form from an extruder in a molten state, and pellets after cooling. And recovered. When the copolymerization ratio of each norbornene monomer in the polymer was calculated from the composition of residual norbornenes in the solution after polymerization (by gas chromatography method), it was almost charged at DCP / MTF / MTD = 10/70/20. It was equal to the composition. This hydrogenated ring-opened polymer had a weight average molecular weight (Mw) of 31,000, a molecular weight distribution (Mw / Mn) of 2.5, a hydrogenation rate of 99.9%, and a Tg of 134 ° C.

  The obtained pellets of the ring-opened polymer hydrogenated product were dried at 70 ° C. for 2 hours using a hot air dryer in which air was circulated to remove moisture. Next, the pellets were subjected to a short shaft extruder having a coat hanger type T die having a lip width of 1.6 m (manufactured by Mitsubishi Heavy Industries, Ltd .: screw diameter 90 mm, T die lip member quality was tungsten carbide, peel strength 44N from molten resin) In the middle of the drying process, the film is stretched 1.5 times at a stretching temperature of 155 ° C. in the width direction, with a film thickness of 60 μm, a width of 1.5 m, and a length of 5000 m. Transparent support A-4 which is a cycloolefin polymer film was obtained.

  As for the retardation of this cycloolefin polymer film, Ro was 70 nm, Rt was 200 nm, and Rt / Ro was 2.86.

<Preparation of transparent support A-5>
(Silicon dioxide dispersion)
Aerosil 972V (manufactured by Nippon Aerosil Co., Ltd.) 12 parts by mass (average diameter of primary particles 16 nm, apparent specific gravity 90 g / liter)
88 parts by mass of ethanol or more was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin. The liquid turbidity after dispersion was 200 ppm. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes to prepare a silicon dioxide dispersion dilution.

(Dope solution)
Cellulose ester (acetyl group substitution degree 2.90, total acyl group substitution degree 2.90)
100 parts by weight Triphenyl phosphate 5 parts by weight Ethyl phthalyl ethyl glycolate 5 parts by weight Silicon dioxide dispersion diluent 10 parts by weight Tinuvin 109 (manufactured by Ciba Specialty Chemicals) 1.2 parts by weight Tinuvin 171 (Ciba Specialty Chemicals) 0.8 parts by mass Methylene chloride 430 parts by mass Ethanol 40 parts by mass The above dope composition is put into a sealed container, heated to 70 ° C., and stirred to completely dissolve the cellulose ester. Obtained. Next, after the dope solution was filtered, the dope solution whose temperature was adjusted to 33 ° C. was fed to the die and uniformly cast with a width of 2.5 m from the die slit onto the stainless steel belt. The cast part of the stainless steel belt was heated from the back with hot water of 37 ° C. After casting, the dope film on the metal support (which is called a web after casting on the stainless steel belt) is dried by applying hot air of 44 ° C., and the residual solvent in the peeling is peeled off at 120 mass%. The web was stretched to a longitudinal stretching ratio of 1.05 times by applying a tension of 1.05 times, and then the web end was gripped with a tenter at a residual solvent amount of 24% and a temperature of 135 ° C., and 1.05 times in the width direction. It extended | stretched so that it might become the draw ratio of. After stretching, the film was held for several seconds while maintaining its width, then the tension in the width direction was relaxed, and the film was dried at 120 ° C. after releasing the width. A cellulose ester film having a thickness of 80 μm, a width of 2.5 m, and a length of 5000 m produced as described above was wound around a core.

  As for the retardation of this cellulose ester film, Ro was 1 nm, Rt was 55 nm, and Rt / Ro was 55.

<Preparation of transparent support A-6>
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) cellulose ester (acetyl group substitution degree 1.90, propionyl group substitution degree 0.10, total acyl) A cellulose ester film was produced in the same manner as in the production of the transparent support A-1, except that the group substitution degree was changed to 2.00).

  As for the retardation of this cellulose ester film, Ro was 115 nm, Rt was 250 nm, and Rt / Ro was 2.17.

<Preparation of transparent support A-7>
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) cellulose ester (acetyl group substitution degree 1.10, propionyl group substitution degree 1.50, total acyl) A cellulose ester film was produced in the same manner as the production of transparent support A-1, except that the degree of group substitution was 2.60) and the film thickness after stretching was changed to 40 μm.

  As for the retardation of this cellulose ester film, Ro was 30 nm, Rt was 100 nm, and Rt / Ro was 3.33.

<Preparation of transparent support A-8>
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.50, total acyl) A cellulose ester film was produced in the same manner as the production of the transparent support A-1, except that the degree of group substitution was 2.30) and the film thickness after stretching was changed to 40 μm.

  As for the retardation of this cellulose ester film, Ro was 100 nm, Rt was 160 nm, and Rt / Ro was 1.6.

<Preparation of transparent support A-9>
The cellulose ester film was prepared in the same manner as in the production of the transparent support A-1, except that the stretching ratio in the width direction was changed from 1.30 times to 1.20 times and the film thickness after stretching was changed to 80 μm. Produced.

  As for the retardation of this cellulose ester film, Ro was 50 nm, Rt was 220 nm, and Rt / Ro was 4.4.

<Preparation of transparent support A-10>
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) cellulose ester (acetyl group substitution degree 0.30, propionyl group substitution degree 1.60, total acyl) The degree of base substitution is 1.90), the stretching ratio in the width direction is changed from 1.30 times to 1.50 times, and the film thickness after stretching is changed to 40 μm. A cellulose ester film was produced in the same manner as the production.

  As for the retardation of this cellulose ester film, Ro was 100 nm, Rt was 100 nm, and Rt / Ro was 1.0.

<Preparation of transparent support A-11>
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) cellulose ester (acetyl group substitution degree 1.10, propionyl group substitution degree 1.60, total acyl) A cellulose ester film was produced in the same manner as the production of the transparent support A-1, except that the degree of group substitution was 2.70) and the film thickness after stretching was changed to 40 μm.

  As for the retardation of this cellulose ester film, Ro was 20 nm, Rt was 70 nm, and Rt / Ro was 3.5.

<Preparation of transparent support A-12>
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) cellulose ester (acetyl group substitution degree 1.60, propionyl group substitution degree 0.90, total acyl) The degree of base substitution is 2.50), the stretching ratio in the width direction is changed from 1.30 times to 1.15 times, and the film thickness after stretching is changed to 100 μm. A cellulose ester film was produced in the same manner as the production.

  As for the retardation of this cellulose ester film, Ro was 50 nm, Rt was 250 nm, and Rt / Ro was 5.0.

<Preparation of transparent support A-13>
Cellulose ester (acetyl group substitution degree 1.80, propionyl group substitution degree 0.70, total acyl group substitution degree 2.50) was changed to cellulose ester (acetyl group substitution degree 1.90, total acyl group substitution degree 1.90). A cellulose ester film was produced in the same manner as in the production of the transparent support A-1, except that the film thickness after stretching was changed to 50 μm.

  As for the retardation of this cellulose ester film, Ro was 120 nm, Rt was 260 nm, and Rt / Ro was 2.17.

《Coating intermediate layer》
<Preparation of intermediate layer composition B-1>
Purple light UV-7605B (manufactured by Nippon Synthetic Chemical Co., Ltd.) 25 parts by mass Photopolymerization initiator (1-hydroxy-cyclohexyl ruphenyl ketone) (Irgacure 184, manufactured by Ciba Specialty Chemicals) 1.25 parts by mass Solvent (PGME / isopropyl alcohol mixed solvent ( (Mass ratio 20/80))
75 parts by mass <Coating of intermediate layer B-1>
The intermediate layer composition B-1 was coated on the produced transparent support A-1 with a slit die, and dried at a hot air temperature of 40 ° C. and a drying time of 30 seconds. Subsequently, ultraviolet rays were irradiated with an irradiation intensity of 50 mJ / cm ² with a high-pressure mercury lamp in an atmosphere with an oxygen concentration of 1.5%, and an intermediate layer having a dry film thickness of 1 μm was provided. The accumulated light quantity of ultraviolet rays is shown in Table 1.

  The coated intermediate layer had a gel fraction of about 50% by mass and was a semi-cured layer.

(Gel fraction)
About 0.1 g of the semi-cured intermediate layer was taken and weighed to measure the mass (W1). Next, this was wrapped in a microporous tetrafluoroethylene membrane (membrane mass W2), immersed in about 50 ml of ethyl acetate for 7 days, and then the soluble component was extracted. This was dried and the total mass (W3) was measured. From these measured values, the gel fraction (mass%) of the semi-cured intermediate layer was determined by the following formula.

Gel fraction (mass%) = {(W3-W2) / W1} × 100
<Preparation of intermediate layer compositions B-2 to B-16>
In the preparation of the intermediate layer composition B-1, intermediate layer compositions B-2 to B-16 were prepared in the same manner except that the urethane acrylate oligomer or acrylate oligomer shown in Table 1 was used.

<Preparation of Intermediate Layer Composition B-17: Comparative Example>
Pentaerythritol triacrylate 25 parts by weight Photopolymerization initiator (1-hydroxy-cyclohexyl ruphenyl ketone) (Irgacure 184, manufactured by Ciba Specialty Chemicals) 1.25 parts by weight Solvent (PGME / isopropyl alcohol mixed solvent (mass ratio 20/80) )
75 parts by mass <Preparation and coating of intermediate layer composition B-18: comparative example>
Poly (bisphenol A carbonate) (manufactured by Aldrich) 8 parts by mass, pentaerythritol triacrylate 2 parts by mass, photopolymerization initiator Irgacure 907 (trade name, manufactured by Ciba Specialty Chemicals) 0.3 part by mass in a toluene / cyclohexanone mixed solvent (Volume ratio 1/2) Dissolved in 40 parts by mass. The obtained solution was applied onto the transparent support 1 using a wire bar coater. The coating layer was heated and dried, and then the coating film was cured by irradiating with an ultraviolet ray of 500 mJ / cm ² using a high-pressure mercury lamp. The surface of the coating film was rubbed to produce an intermediate layer.

<Preparation and Coating of Intermediate Layer Composition B-19: Comparative Example>
(Synthesis of acrylic block polymer (A))
Octadecyl acrylate (30 g) and 2,2-bipyridine (0.5 g) were added to a four-necked flask equipped with a mechanical stirrer, nitrogen introduction tube, cooling tube and rubber septum, and the system was purged with nitrogen for 2 hours. . Copper bromide (0.15 g) and ethyl 2-bromoisobutyrate (0.2 g) were added thereto under a nitrogen stream, and polymerization was performed at 80 ° C. for 40 hours under a nitrogen stream. After confirming that the polymerization rate of the monomer was 80% by mass or more, 2-ethylhexyl acrylate (glass transition temperature of homopolymer: -70 ° C., 20 g), 2,2-bipyridine (0.5 g), bromide Copper (0.15 g) was added under a nitrogen stream and polymerized at 80 ° C. for 20 hours and then at 90 ° C. for 20 hours. The product was diluted with toluene, filtered, added to methanol, reprecipitated and washed three times for purification to obtain an acrylic block polymer (A). The number average molecular weight of the polymer (A) was 51,000, the weight average molecular weight was 77500, and the molecular weight distribution (Mw / Mn) was 1.52.

A block obtained by dissolving 100 parts by mass of an acrylic block polymer (A) and 2 parts by mass of 2- (p-methoxyphenyl) -4,6-bis- (trichloromethyl) -s-triazine in 300 parts by mass of cyclopentanone. A polymer composition was prepared. The block polymer composition was coated on the transparent support 1 using a spin coater, dried at 90 ° C. for 2 minutes, and oriented to obtain an uncured intermediate layer. Using a fusion D-bulb and a conveyor-type UV irradiation device, the uncured intermediate layer produced under the condition of 25 ° C. is passed once through the conveyor, irradiated with ultraviolet rays through a quartz filter, and a semi-cured intermediate layer (film thickness) 2 μm) was obtained. In addition, when it measured using the ultraviolet light quantity measuring machine (EIT company make, UV Power Pack), UVC (250-260 nm), UVB (280-320 nm), UVA when an uncured intermediate layer is passed through a conveyor once. The total light amount of (320-390 nm) and UVV (395-445 nm) was 1.0 J / cm ² . The gel fraction of the semi-cured intermediate layer was about 25% by mass.

<Preparation and Coating of Intermediate Layer Composition B-20: Comparative Example>
The surface of the produced transparent support 1 was subjected to saponification treatment, and an intermediate layer composition having the following composition was applied onto the film with a wire bar coater so as to be 20 ml / m ² . The intermediate layer was formed by drying with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds. Next, the formed intermediate layer was rubbed in a direction parallel to the slow axis direction of the film.

The following modified polyvinyl alcohol (AL-1) 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde 0.5 parts by weight

<Coating of intermediate layers B-2 to B-20>
In the combinations shown in Table 2, each of the intermediate layers was coated in the same manner using the prepared transparent supports A-1 to A-13 and the intermediate layer coating compositions B-2 to B-20.

  In addition, the optical compensation films 10, 11, 12, and 13, which will be described later, have an ultraviolet ray integrated light amount so that the gel fraction of the intermediate layer B-9 is 25% by mass, 30% by mass, 80% by mass, and 85% by mass, respectively. The intermediate layer was semi-cured and formed.

<Coating of optically anisotropic layer>
Next, an optically anisotropic layer was provided on each of the obtained intermediate layers using the following polymerizable liquid crystal composition (C-1).

<Preparation and coating of polymerizable liquid crystal composition (C-1)>
45% by mass of the compound of the following formula (a),

  45% by mass of the compound of the following formula (b),

  10% by mass of the compound of the following formula (d),

A polymerizable liquid crystal composition comprising: The nematic-isotropic liquid phase transition temperature of this polymerizable liquid crystal composition was 73 ° C. Photopolymerization initiator Lucillin TPO (manufactured by Bassf) 0.2% and hindered amine LS-765 (manufactured by Sankyo Lifetech Co., Ltd.) 0.1% were added to 99.7% of the above polymerizable liquid crystal composition to obtain a polymerizable liquid crystal composition. A product (C-1) was prepared. Next, a xylene solution containing 33% of the polymerizable liquid crystal composition (C-1) was prepared. This xylene solution was applied to the intermediate layer with a thickness of 5 μm by a die coater. The coated film was irradiated with an ultraviolet ray of 250 mJ / mm for 80 seconds at an oxygen concentration of 0.2% and a temperature of 38 ° C. to cure the polymerizable liquid crystal composition (C-1) to obtain an optically anisotropic layer. .

  When the optical compensation film coated with the obtained optically anisotropic layer was evaluated using a polarizing microscope, it appeared black when sandwiched between crossed Nicol polarizers, and the optical compensation film was observed between the crossed Nicol polarizers. A white color was observed when the compensation film was tilted. Therefore, it was confirmed that the optically anisotropic layer was vertically aligned.

  When the retardation of the optically anisotropic layer was measured, Ro was 0.5 nm, Rt was −288 nm, and Ro of the optical compensation film 9 of the present invention on which the optically anisotropic layer was laminated was 70 nm and Rt was − It was 88 nm.

  Further, D (Ro) 1 defined by the above formulas 9 to 12 is 0.9, D (Ro) 2 is -3 nm, D (Rt) 1 is 0.7, and D (Rt) 2 is -36 nm. It was.

  As described above, optical compensation films 1 to 36 shown in Table 2 were produced.

<Evaluation>
(Adhesion)
The produced optical compensation film is left in a constant temperature layer at 80 ° C. and 90% RH for 120 hours and then taken out. Eleven cuts were made on the surface of the liquid crystal alignment layer of the optical compensation film with a cutter knife so as to cross vertically and horizontally at 1 mm intervals to form a grid (100 pieces), and a cellophane tape was attached thereto and then peeled off. The same operation was performed three times, and the adhesion was evaluated according to the following criteria.

  A: No cross-cuts were peeled off by three operations.

  ◯: The number of grids in which the area of 1/10 or less of the grids was peeled by three operations was 1 to 2.

(Triangle | delta): The grid of the grid which peeled 1/10 or less area | region of the grid of 3 times by the operation of 3 times was 3-10, or the peeling of 1/2 or less was 1-5.

  X: There was peeling exceeding the standard of Δ.

(Orientation defect)
The prepared optical compensation film was observed under a polarizing microscope, the orientation state and orientation defects were evaluated, and the number of orientation defects generated in the optically anisotropic layer was observed with an optical microscope. The number (average value in the range of 1.0 mm ² ) was counted.

：: 0 to 1 ○: 2 to 3 Δ: 4 to 10 ×: 11 or more The above evaluation results are shown in Table 2.

  From Table 2, it can be seen that the optical compensation film of the present invention has few alignment defects in the optically anisotropic layer and has excellent wet heat durability in the adhesion between the support and the optically anisotropic layer.

  Moreover, from the evaluation results of the optical compensation films 9 to 13, the intermediate layer was made semi-cured so that the gel fraction was in the range of 30 to 80% by mass, and the optical anisotropic layer was applied, which was more excellent. It was also found that adhesion can be obtained.

Example 2
<Production of polarizing plate>
The optical compensation films 9, 22 and 25 to 36 produced above were alkali-treated with a 2.5 mol / L sodium hydroxide aqueous solution at 40 ° C. for 60 seconds, washed with water for 3 minutes and saponified to obtain an alkali-treated film.

  Next, a 120 μm-thick polyvinyl alcohol film was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. This was washed with water and dried to obtain a polarizing film.

  Next, the prepared polarizing film and a commercially available polarizing plate protective film, Konica Minolta-Tac, KC4UY (manufactured by Konica Minolta Opto Co., Ltd.) were saponified by the above method, and a fully saponified polyvinyl alcohol 5% aqueous solution was adhered. As the agent, a polarizing plate on the viewing side was prepared by laminating an optical compensation film, a polarizing film, and KC4UY in this order.

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

  The polarizing plate on the viewing side of the Hitachi liquid crystal television Wooo W17-LC50, which is an IPS mode type liquid crystal display device, is peeled off from the viewing side, and the polarizing plate prepared as described above is aligned with the absorption axis of the polarizing plate. The IPS mode type liquid crystal display device was produced by pasting on the glass surface. In that case, it bonded so that the optical compensation film of a polarizing plate might become a liquid crystal cell side.

<Evaluation of liquid crystal display device>
(Viewing angle)
For the evaluation of viewing angle characteristics, the transmitted light amount during black display and white display was measured using EZ-contrast manufactured by ELDIM. For the evaluation of the viewing angle, contrast = (transmitted light amount during white display) / (transmitted light amount during black display) is calculated, and the inclination angle from the normal direction to the panel surface showing 10 or more is 60 ° or more on the left and right. The evaluation was “no problem” in practical use.

(Color)
Color measurement at the time of black display was performed with Topcon SR-3A.

Tint measurement was performed between the front and a tilt angle of 60 ° (azimuth angle 45 °) (reference to the front), and ((xx ′) ² + (y−y ′) ² ) ^1/2 was evaluated. . The smaller the number, the more stable the color.

  * In the formula, front: (x, y), diagonal: (x ', y').

◎: Less than 0.02 ○: 0.02 or more and less than 0.05 Δ: 0.05 or more and less than 0.09 ×: 0.09 or more (color unevenness)
Color unevenness was evaluated visually.

A: Color unevenness is not observed at all. ○: Color unevenness is observed only partially. Δ: Color unevenness is observed over the entire surface. The results are shown in Table 3.

  In this measurement, it can be seen that the liquid crystal display device of the present invention is superior in view angle, color and color unevenness.

Example 3
An optical compensation film 37 was produced in the same manner as in the optical compensation film 9, except that the polymerizable liquid crystal composition (C-1) was replaced with the following polymerizable liquid crystal composition (C-2).

  The optical compensation film 37 exhibited excellent characteristics similarly to the optical compensation film 9 in Table 2 and the liquid crystal display device 1 in Table 3.

<Preparation and coating of polymerizable liquid crystal composition (C-2)>
50% by mass of the compound of the following formula (e),

  50% by mass of the compound of the following formula (f),

  And 1.5 parts by mass of a photopolymerization initiator “IRG-651” (manufactured by Ciba Specialty Chemicals) and 0.5 part by mass of a nonionic surfactant “MEGAFAC F-177” (manufactured by Dainippon Ink & Chemicals, Inc.) A polymerizable liquid crystal composition (C-2) comprising:

  Next, a xylene solution containing 33% of the polymerizable liquid crystal composition (C-2) was prepared. This xylene solution was applied with a thickness of 5 μm onto the transparent support A-1 / intermediate layer B-9 by a die coater. The coated film was irradiated with UV light of 250 mJ / mm for 80 seconds at an oxygen concentration of 0.2% and a temperature of 38 ° C. to cure the polymerizable liquid crystal composition (C-2), thereby obtaining an optically anisotropic layer. .

  When the retardation of the optically anisotropic layer was measured, Ro was 1.5 nm, Rt was -250 nm, and the optical compensation film of the present invention in which the optically anisotropic layer was laminated had Ro of 70 nm and Rt of -50 nm. Met.

  In addition, D (Ro) 1 defined by the formulas 9 to 12 is 0.9, D (Ro) 2 is -2.80 nm, D (Rt) 1 is 0.60, and D (Rt) 2 is -30 nm. Met.

Example 4
The polarizing plate used in Example 2 was incorporated using AQ-32AD5 (manufactured by Sharp Corporation), which is a VA mode type liquid crystal display device, instead of Hitachi liquid crystal television Wooo W17-LC50 used in Example 2. A liquid crystal display device was manufactured and evaluated in the same manner as in Example 2. As a result, the liquid crystal display device using the optical compensation film of the present invention was superior in view angle, color tone, and color unevenness. .

Claims (10)

An optical compensation film having an intermediate layer and an optically anisotropic layer in this order on a transparent support, the intermediate layer comprising a cured product of a urethane acrylate oligomer or an acrylate oligomer, wherein the optically anisotropic layer is substantially An optical compensation film characterized in that it is a layer in which the orientation of a vertically aligned rod-like liquid crystal is fixed. The optical compensation film according to claim 1, wherein the urethane acrylate oligomer or the acrylate oligomer satisfies the following formulas 1 to 3.
Formula 1 1500 ≦ Mw ≦ 6000
Formula 2 2 ≦ number of oligomer functional groups ≦ 4
Formula 3 500 ≦ Mw / number of oligomer functional groups ≦ 3000
(Wherein, Mw represents the weight average molecular weight of the oligomer.) The optical compensation film according to claim 1 or 2, wherein the intermediate layer comprises a cured product of urethane acrylate oligomer. The optical compensation film according to any one of claims 1 to 3, wherein the transparent support is a cellulose ester film satisfying the following formulas 4 to 6.
Formula 4 30 ≦ Ro ≦ 115 (nm)
Formula 5 100 ≦ Rt ≦ 250 (nm)
Formula 6 1.6 ≦ Rt / Ro ≦ 4.4
However, said Ro and Rt are the retardation values represented by the following formula | equation.
Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(In the formula, the refractive index in the slow axis direction in the film plane is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, the refractive index in the thickness direction of the film is nz, d is the thickness of the film ( nm).) The optical compensation film according to claim 4, wherein the cellulose ester film contains a cellulose ester satisfying the following formulas 7 to 8.
Formula 7 2.00 ≦ (X + Y) ≦ 2.60
Formula 8 0.10 ≦ Y ≦ 1.50
(In the formula, X and Y represent the acyl group substitution degree of the cellulose ester, X represents the acetyl group substitution degree, and Y represents the propionyl substitution degree.) A polarizing plate comprising the optical compensation film according to any one of claims 1 to 5 on at least one surface. A liquid crystal display device using the polarizing plate according to claim 6. A method for producing an optical compensation film in which an intermediate layer and an optically anisotropic layer are provided in this order on a transparent support, comprising:
a) urethane acrylate oligomer or acrylate oligomer,
b) a photopolymerization initiator,
c) An intermediate layer composition composed of a solvent is applied, dried, and semi-cured by ultraviolet irradiation to form an intermediate layer, on which an optically different layer is a layer in which the alignment of substantially vertically aligned rod-like liquid crystals is fixed. A method for producing an optical compensation film, comprising forming an isotropic layer. The method for producing an optical compensation film according to claim 8, wherein the transparent support is a cellulose ester film that is stretched in at least one axial direction and satisfies the following formulas 4 to 6.
Formula 4 30 ≦ Ro ≦ 115 (nm)
Formula 5 100 ≦ Rt ≦ 250 (nm)
Formula 6 1.6 ≦ Rt / Ro ≦ 4.4
However, said Ro and Rt are the retardation values represented by the following formula | equation.
Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(In the formula, the refractive index in the slow axis direction in the film plane is nx, the refractive index in the direction perpendicular to the slow axis in the plane is ny, the refractive index in the thickness direction of the film is nz, d is the thickness of the film ( nm).) The method for producing an optical compensation film according to claim 8, wherein the intermediate layer is semi-cured so as to have a gel fraction of 30 to 80% by mass.