JPWO2015012014A1 - Polarizing plate and VA liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide a polarizing plate capable of maintaining strong adhesion between a polarizer and a retardation film in a high-temperature and high-humidity environment even when an acrylic active energy ray-curable adhesive is used. And a VA liquid crystal display device using the polarizing plate. The polarizing plate of the present invention is a polarizing plate in which a retardation film and a protective film are respectively bonded to one surface of a polarizer and bonded with an acrylic active energy ray-curable adhesive, The retardation film is a retardation film containing a cellulose ester and a compound that suppresses the permeability of the adhesive, the acyl group substitution degree of the cellulose ester is within a specific range, and the retardation film The penetration depth of the test solution when 4-hydroxydibutyl acrylate is used as a test solution for evaluating the permeability of the adhesive to the adhesive is in the range of 0.1 to 1.0 μm at 50 ° C. for 30 seconds. It is characterized by that.

Description

  The present invention relates to a polarizing plate and a VA (Virtual Alignment) type liquid crystal display device using the polarizing plate. More specifically, by using an acrylic active energy ray-curable adhesive, the polarizer is firmly bonded to the polarizer. The present invention relates to a polarizing plate capable of maintaining strong adhesiveness even when exposed to a high temperature and high humidity environment for a long time, and a VA liquid crystal display device using the polarizing plate without causing color unevenness.

  A liquid crystal display device usually has a liquid crystal cell and a pair of polarizing plates sandwiching the liquid crystal cell. The polarizing plate has a polarizer and a pair of protective films that sandwich the polarizer.

  As the polarizer constituting the polarizing plate, for example, an iodine-based polarizer obtained by stretching a polyvinyl alcohol film adsorbed with iodine is widely used because of its high transmittance and degree of polarization.

  A polarizing plate is generally obtained by bonding a polarizer and a protective film together with an aqueous adhesive in which a polyvinyl alcohol compound is dissolved in water. As a protective film used with such an aqueous adhesive, a cellulose ester film is preferably used. This is because the cellulose ester film not only has high water vapor permeability, but also can be well bonded to the polarizer by saponifying and hydrophilizing the film surface by immersing in an alkaline aqueous solution.

  However, in the method for producing a polarizing plate using an aqueous adhesive, after the polarizer and the protective film are bonded together, a drying process for removing moisture and the like contained in the aqueous adhesive is required. If the drying process is included in the production process of the polarizing plate, it is not preferable for improving the productivity of the polarizing plate.

  Moreover, the polarizing plate manufactured using a water-based adhesive has problems such as a large dimensional change at high temperatures and high temperatures and high humidity. In particular, in a thin and large-screen liquid crystal display device, a polarizing plate manufactured using a water-based adhesive is likely to undergo dimensional changes due to the heat of the backlight or the temperature. Therefore, there is a problem that light leakage occurs in a part of the screen of the liquid crystal display device and color unevenness occurs.

  For these reasons, it has been proposed to use an active energy ray curable adhesive, particularly an ultraviolet curable adhesive, instead of the water-based adhesive. For example, an ultraviolet curable adhesive in which an acrylic oligomer such as epoxy acrylate, urethane acrylate, or polyester acrylate is diluted with an acrylic or methacrylic monomer has been proposed (see, for example, Patent Document 1). In addition, as an active energy ray-curable adhesive having good adhesion and water resistance, an adhesive containing a specific monofunctional monomer and a polyfunctional monomer having a (meth) acrylamide group has been proposed. (For example, refer to Patent Document 2).

  By the way, it is preferable that the thickness of the adhesive layer of the active energy ray-curable adhesive is 1.0 μm or less and is as thin as possible. This is because when the adhesive layer is cured by ultraviolet rays, the adhesive layer is also absorbable in the visible light region. Therefore, when the adhesive layer is thick, the yellow color is conspicuous and affects the optical properties. Furthermore, compared with the conventional water-based adhesive, the active energy ray-curable adhesive is expensive, and further thinning is desired from the viewpoint of cost reduction.

  On the other hand, in polarizing plates used for optical films such as displays, a cellulose ester-based protective film having a small thickness direction retardation (also referred to as “retardation”) to eliminate optical coloring of the polarizer. Is advantageous and is used universally. As the cellulose ester-based protective film, an acyl group-substituted cellulose having a controlled acyl group substitution degree is used as a material. Preferably, the acetyl group substitution degree is 1.8 to 2.7, and the propionyl group substitution degree is 0. An acyl group-substituted cellulose ester-based protective film controlled to 0.1 to 1.0 is used. In order to further reduce the retardation in the thickness direction, a cellulose ester polymer obtained by adding a plasticizer such as polyester to the cellulose ester polymer is preferably used (for example, see Patent Document 3). .

  However, cellulose ester-based protective films substituted with propionyl groups and cellulose ester-based protective films to which plasticizers are added are highly soluble in highly polar acrylic active energy ray-curable adhesives. When the adhesive was combined with the system protective film, the surface of the protective film was swollen and dissolved in the bonding step, and the thin adhesive layer disappeared, so that sufficient adhesion could not be obtained.

  Therefore, even when the acrylic active energy ray-curable adhesive is applied to a thin film uniformly with a thickness of less than 1.0 μm, the cellulose ester protective film and the polarizer are firmly bonded, and in a high temperature and high humidity environment. Even if it is exposed to a long time, a polarizing plate having good adhesion is strongly desired.

JP 61-246719 A JP 2010-077199 A Japanese Patent No. 5120072

  The present invention has been made in view of the above-mentioned problems and situations, and the problem to be solved is that even when a thin layer of an acrylic active energy ray-curable adhesive having a thickness of less than 1.0 μm is used, polarized light is used. A polarizing plate that can be firmly bonded in the bonding between the optical element and the retardation film, and can maintain strong adhesiveness even when exposed to a high temperature and high humidity environment for a long time, and the polarizing plate An object of the present invention is to provide a VA liquid crystal display device using a polarizing plate and having no color unevenness.

  In order to solve the above-mentioned problems, the present inventor, from the resin composition containing cellulose ester and a compound that suppresses the permeability of the acrylic active energy ray-curable adhesive in the process of examining the cause of the above-mentioned problem The present inventors have found that the above problems can be solved by using a retardation film as a polarizing plate, and have reached the present invention.

  That is, the said subject which concerns on this invention is solved by the following means.

1. The retardation film and the protective film are each a polarizing plate bonded opposite to one of the surfaces of the polarizer,
The polarizer and the retardation film are bonded with an acrylic active energy ray-curable adhesive,
The retardation film includes at least a cellulose ester,
A compound that suppresses the permeability of the acrylic active energy ray-curable adhesive;
A retardation film produced from a resin composition containing
The acyl group substitution degree of the cellulose ester satisfies the following formula (I),
And the penetration depth of the test solution when 4-hydroxydibutyl acrylate is used as a test solution for evaluating the permeability of the acrylic active energy ray-curable adhesive into the retardation film,
A polarizing plate characterized by being within a range of 0.1 to 1.0 μm at 50 ° C. for 30 seconds.

Formula (I): 2.0 ≦ X + Y ≦ 2.6
(However, in formula (I), X represents an acetyl group substitution degree and Y represents a propionyl group substitution degree or a butyryl group substitution degree.)

  2. The retardation film has an in-plane retardation value Ro in a range of 40 nm ≦ | Ro | ≦ 100 nm in a measurement wavelength of 590 nm, 23 ° C. and 55% RH, and a film thickness direction level. The retardation value Rt is in the range of 100 nm ≦ | Rt | ≦ 300 nm.

  3. Item 1 or Item 2 is characterized in that the compound that suppresses the permeability of the acrylic active energy ray-curable adhesive is a polyhydric alcohol ester having a structure represented by the following general formula (1). The polarizing plate as described in.

General formula (1)
B ₁ -G ₁ -B ₂
(However, in General Formula (1), B ₁ and B ₂ each independently represents an aliphatic monocarboxylic acid residue or an aromatic monocarboxylic acid residue. G ₁ has 2 to 12 carbon atoms. Represents an alkylene glycol residue having a straight-chain or branched structure.

4). B ₁ and B ₂ in the polyhydric alcohol ester having the structure represented by the general formula (1) are both aliphatic monocarboxylic acid residues having 1 to 10 carbon atoms. 4. The polarizing plate according to item 3 above.

  5). Content of the said polyhydric alcohol ester exists in the range of 1-10 mass parts with respect to 100 mass parts of said cellulose esters, The polarizing plate of 3rd term | claim or 4th term | claim characterized by the above-mentioned.

  6). The polarizing plate according to any one of Items 1 to 5, wherein the resin composition contains a compound having a 5-membered or 6-membered aromatic heterocyclic group.

  7). 7. The polarizing plate according to item 6, wherein the compound having a 5-membered or 6-membered aromatic heterocyclic group is a compound having a structure represented by the following general formula (2).

（ただし、一般式（２）中、Ａ_１及びＡ_２は、それぞれ独立に、アルキル基、シクロアルキル基、芳香族炭化水素環基又は芳香族複素環基を表す。Ｂは、芳香族炭化水素環又は芳香族複素環を表す。Ｔ_１及びＴ_２は、それぞれ独立に、１，２，４−トリアゾール環を表す。Ｌ_１、Ｌ_２、Ｌ_３及びＬ_４は、それぞれ独立に、単結合又は２価の連結基を表す。ｎは０〜５の整数を表す。）

(In the general formula (2), A ₁ and A ₂ each independently represents an alkyl group, a cycloalkyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group. B is an aromatic hydrocarbon. T ₁ and T ₂ each independently represent a 1,2,4-triazole ring, L ₁ , L ₂ , L ₃ and L ₄ each independently represent a single bond Alternatively, it represents a divalent linking group, and n represents an integer of 0 to 5.)

  8). The content of the compound having a 5-membered or 6-membered aromatic heterocyclic group is in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester. 8. The polarizing plate according to item 7.

  9. The polarizing plate according to any one of Items 1 to 8, wherein the resin composition contains a sugar ester.

  10. Content of the said sugar ester exists in the range of 1-20 mass parts with respect to 100 mass parts of said cellulose esters, The polarizing plate of Claim 9 characterized by the above-mentioned.

  11. A VA liquid crystal display device using the polarizing plate according to any one of items 1 to 10.

  Even when a thin acrylic active energy ray curable adhesive having a thickness of less than 1.0 μm (hereinafter also simply referred to as “acrylic curable adhesive”) is used by the above means of the present invention. A polarizing plate that can be firmly bonded in the bonding between the polarizer and the retardation film, and can maintain strong adhesiveness even when exposed to a high temperature and high humidity environment for a long time. In addition, it is possible to provide a VA liquid crystal display device using the polarizing plate and free from uneven color.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  In general, a cellulose ester-based protective film is formed from a resin composition containing a polyester and a sugar ester in addition to a cellulose ester. In recent years, for the adhesion between a protective film having such a composition and a polarizer (also referred to as a polarizing film), it has been proposed to use an active energy ray curable adhesive or an ultraviolet curable adhesive instead of an aqueous adhesive. Has been. However, when an acrylic curable adhesive is used among the ultraviolet curable adhesives, a cellulose ester protective film substituted with a propionyl group or a cellulose ester protective film to which a plasticizer is added are highly polar acrylic Because of its high solubility in curable adhesives, when the adhesive is combined with the above cellulose ester-based protective film, the surface of the protective film swells and dissolves in the bonding process, and the thin adhesive layer disappears. A sufficient adhesion could not be obtained.

  In the present invention, by adding a compound that suppresses the permeability of the acrylic curable adhesive to the cellulose ester to form a film, the acrylic curable adhesive is prevented from penetrating into the film. Can do. As a result, the amount of the acrylic curable adhesive remaining on the film is increased, and more adhesive is present in the vicinity of the film surface, which makes it possible to firmly adhere to the polarizer. .

  The reason why the penetration of the acrylic curable adhesive into the film is suppressed by adding the polyhydric alcohol ester having the structure represented by the general formula (1) is not clear, but is as follows. The mechanism is estimated. First, the polyhydric alcohol ester used in the present invention is highly hydrophobic and has a characteristic of poor compatibility with an acrylic curable adhesive. For this reason, it can be estimated that the penetration of the acrylic curable adhesive is suppressed by the presence of the polyhydric alcohol ester in the film. In this invention, even if the addition amount was a small addition amount of 10 parts by mass or less with respect to 100 parts by mass of the cellulose ester, a particularly great effect was exhibited. The second reason is that the molecular weight of the polyhydric alcohol ester is small, and even though it is hydrophobic, it has a polar group called ester and has a site that interacts with cellulose. It is estimated that the effect is further enhanced.

  The retardation film according to the present invention is generally produced by dissolving in a solvent. However, when the solvent in the film is dried, the polyhydric alcohol ester has a low molecular weight and is hydrophobic, and thus has high affinity with the solvent. It is estimated that the film moves to the film surface side simultaneously with the drying of the solvent and is unevenly distributed on the outermost surface of the film. On the other hand, if the compound that suppresses the permeability of the acrylic curable adhesive does not have a polar group such as an ester, the interaction with cellulose is small, and it flows out from the film surface to the outside of the film as it is to cause bleed out. .

  For this reason, like the polyhydric alcohol ester used in the present invention, it has a small molecular weight, is hydrophobic, and has an ester group. It is considered that a film having excellent quality that suppresses the permeability of the mold adhesive and does not cause bleed-out or the like can be obtained.

The schematic diagram which shows an example of a structure of the VA type liquid crystal display device using the polarizing plate of this invention.

The polarizing plate of the present invention is a polarizing plate in which a retardation film and a protective film are bonded to face either one of the polarizers, respectively.
The polarizer and the retardation film are bonded with an acrylic active energy ray-curable adhesive,
The retardation film includes at least a cellulose ester,
A compound that suppresses the permeability of the acrylic active energy ray-curable adhesive;
A retardation film produced from a resin composition containing
The acyl group substitution degree of the cellulose ester satisfies the following formula (I),
And the penetration depth of the test solution when 4-hydroxydibutyl acrylate is used as a test solution for evaluating the permeability of the acrylic active energy ray-curable adhesive into the retardation film,
It is characterized by being in the range of 0.1 to 1.0 μm at 50 ° C. for 30 seconds.

Formula (I): 2.0 ≦ X + Y ≦ 2.6
(However, in formula (I), X represents an acetyl group substitution degree and Y represents a propionyl group substitution degree or a butyryl group substitution degree.)
This feature is a technical feature common to the inventions according to claims 1 to 11.

  As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the retardation film has an in-plane retardation value Ro of 40 nm ≦ | Ro in a measurement wavelength of 590 nm and a 23 ° C./55% RH environment. It is preferable that | ≦ 100 nm and the retardation value Rt in the film thickness direction be in the range of 100 nm ≦ | Rt | ≦ 300 nm because the viewing angle expansion effect is large.

  Moreover, the compound which suppresses the permeability of the acrylic curable adhesive is a polyhydric alcohol ester having a structure represented by the general formula (1), so that the permeability of the acrylic curable adhesive is improved. This is preferable because the effect of inhibiting is excellent.

Further, B ₁ and B ₂ in the polyhydric alcohol ester having the structure represented by the general formula (1) are both aliphatic monocarboxylic acid residues having 1 to 10 carbon atoms. It is preferable that there is an effect of suppressing the permeability of the acrylic curable adhesive.

  Moreover, the content of the polyhydric alcohol ester is in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester, thereby sufficiently exhibiting the permeability suppressing effect of the acrylic curable adhesive. This is preferable.

  In addition, it is preferable that the resin composition contains a compound having a 5-membered or 6-membered aromatic heterocyclic group because it has an effect of suppressing the fluctuation of the retardation value with respect to the fluctuation of the moisture content. .

  Furthermore, the compound having a 5-membered or 6-membered aromatic heterocyclic group is a compound having a structure represented by the general formula (2), so that the fluctuation of the retardation value with respect to the fluctuation of the moisture content This is preferable because of the large effect of suppressing the above.

  Moreover, it is with respect to the fluctuation | variation of a moisture content that content of the compound which has the said 5-membered or 6-membered aromatic heterocyclic group exists in the range of 1-10 mass parts with respect to 100 mass parts of said cellulose esters. Therefore, the effect of suppressing the fluctuation of the phase difference value can be sufficiently exhibited, which is preferable.

  Furthermore, it is preferable that the resin composition contains a sugar ester because the plasticizing effect is excellent.

  Furthermore, it is preferable that the content of the sugar ester is in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the cellulose ester because a sufficient plasticizing effect is obtained.

  The polarizing plate can be suitably used for a VA liquid crystal display device.

  Hereinafter, the constituent elements of the present invention, and modes and modes for carrying out the present invention will be described in detail. In the present application, “to” is used in the sense of including the numerical values described before and after the lower limit value and the upper limit value.

≪Polarizing plate≫
The polarizing plate of the present invention is a polarizing plate in which a retardation film and a protective film are respectively bonded to face one of the polarizers, and the polarizer and the retardation film are acrylic. From the resin composition containing at least a cellulose ester and a compound that suppresses the permeability of the acrylic active energy ray-curable adhesive. The produced retardation film has an acyl group substitution degree of the cellulose ester satisfying the following formula (I), and evaluates the permeability of the acrylic active energy ray-curable adhesive into the retardation film. When 4-hydroxydibutyl acrylate is used as the test solution, the penetration depth of the test solution is in the range of 0.1 to 1.0 μm at 50 ° C. for 30 seconds. It is a feature is.

Formula (I): 2.0 ≦ X + Y ≦ 2.6
(However, in formula (I), X represents an acetyl group substitution degree and Y represents a propionyl group substitution degree or a butyryl group substitution degree.)

  Hereinafter, the retardation film, the polarizer and the protective film constituting the polarizing plate of the present invention will be described in order.

<< retardation film >>
The retardation film according to the present invention is a retardation film having a viewing angle widening effect, and is a retardation film used for a polarizing plate for the purpose of improving the viewing angle characteristics of a VA liquid crystal display device. Moreover, generally it also has a function as a protective film of a polarizing plate.

  The retardation film according to the present invention is a retardation film formed from a resin composition containing a cellulose ester and a compound that suppresses the permeability of an acrylic curable adhesive.

<Cellulose ester>
The cellulose ester used in the retardation film according to the present invention has an acyl group substitution degree that satisfies the following formula (I).

Formula (I): 2.0 ≦ X + Y ≦ 2.6
However, in the formula, X represents an acetyl group substitution degree, and Y represents a propionyl group substitution degree or a butyryl group substitution degree.

  When X + Y is within the above range, a retardation value Ro in the in-plane direction and a retardation value Rt in the film thickness direction necessary for obtaining a viewing angle widening effect as a retardation film are obtained. When X + Y is less than 2.0, performance (humid heat resistance) against high-temperature humid heat environment is not obtained, and when it exceeds 2.6, a retardation value necessary for obtaining the above-described viewing angle widening effect is obtained. I can't.

(Description of degree of substitution)
The acyl group substitution degree of the cellulose ester used in the present invention will be described below.
Cellulose is a resin in which β-glucose is linearly polymerized with glycosidic bonds, and the glucose unit, which is a structural unit, has hydroxy groups at the 2nd, 3rd and 6th positions. The cellulose ester according to the present invention is a polymer obtained by esterifying a part of these hydroxy groups with an acyl group.

  The acyl group substitution degree represents the total ratio of esterification of the 2-, 3- and 6-position hydroxy groups of the glucose unit which is a repeating unit. Specifically, the degree of substitution is 1 when each of the hydroxyl groups at the 2nd, 3rd and 6th positions of glucose is 100% esterified. Therefore, when all the 2nd, 3rd and 6th positions of glucose constituting cellulose are 100% esterified, the total degree of substitution is 3 at the maximum.

  Examples of the acyl group include an acetyl group, a propionyl group, a butyryl group, and the like. Of these, the degree of substitution with an acetyl group is represented by a substitution degree X, and the percentage substituted with a propionyl group or a butyryl group is represented by a substitution degree Y. The portion not substituted with an acyl group is usually present as a hydroxy group. In the present invention, the total substitution degree of the acyl group in the glucose unit constituting the cellulose ester is represented by X + Y.

  As the cellulose ester, a mixed fatty acid ester of cellulose having a propionate group or a butyrate group in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate can be used. .

  The butyryl group that forms butyrate may be linear or branched.

In order to obtain preferable optical characteristics, cellulose esters having different degrees of substitution may be mixed and used. The mixing ratio is preferably 10:90 to 90:10 (mass ratio).
The measuring method of the substitution degree of an acyl group can be measured according to ASTM-D817-96.

  The number average molecular weight of the cellulose ester used in the present invention is preferably in the range of 60,000 to 300,000 because the mechanical strength of the resulting film is strong. Furthermore, the thing of 70000-200000 is used preferably.

  The weight average molecular weight Mw and number average molecular weight Mn of the cellulose ester were measured using gel permeation chromatography (GPC).

  The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three products manufactured by Showa Denko KK)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 500 to 1,000,000 13 calibration curves were used. Thirteen samples are used at approximately equal intervals.

  The cellulose used as a raw material of the cellulose ester used in the present invention is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. Moreover, the cellulose ester obtained from them can be mixed and used in arbitrary ratios, respectively.

  The cellulose ester according to the present invention can be produced by a known method. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804.

  Generally, cellulose is esterified by mixing cellulose as a raw material, a predetermined organic acid (such as acetic acid or propionic acid), an acid anhydride (such as acetic anhydride or propionic anhydride), and a catalyst (such as sulfuric acid). The reaction proceeds until the triester is formed. In the triester, the three hydroxy groups of the glucose unit are substituted with an acyl group of an organic acid. When two or more organic acids are used at the same time, a mixed ester type cellulose ester (cellulose acylate), for example, cellulose acetate propionate or cellulose acetate butyrate can be produced. Next, a cellulose ester having a desired acyl group substitution degree is synthesized by hydrolyzing the cellulose triester. Thereafter, the cellulose ester can be obtained through steps such as filtration, precipitation, washing with water, dehydration, and drying.

  The mixed ester type cellulose ester used in the present invention can be synthesized using an acid anhydride or acid chloride as an acylating agent. When the acylating agent is an acid anhydride, an organic acid (for example, acetic acid) or methylene chloride is used as a reaction solvent. As the catalyst, an acidic catalyst such as sulfuric acid is used. When the acylating agent is an acid chloride, a basic compound is used as a catalyst. In the industrially most common synthesis method, cellulose is esterified with a mixed organic acid component containing organic acids (acetic acid, propionic acid, butyric acid) corresponding to acetyl group and propionyl group or their anhydrides to form cellulose ester. Synthesize.

  The amount of the acetylating agent, propionylating agent, and butyrylating agent used is adjusted so that the ester to be synthesized falls within the range of the substitution degree described above. The amount of the reaction solvent used is preferably 100 to 1000 parts by mass, more preferably 200 to 600 parts by mass with respect to 100 parts by mass of cellulose. It is preferable that the usage-amount of an acidic catalyst is 0.1-20 mass parts with respect to 100 mass parts of cellulose, More preferably, it is 0.4-10 mass parts.

  The reaction temperature is preferably 10 to 120 ° C, more preferably 20 to 80 ° C. Other acylating agents and esterifying agents (for example, sulfate esterifying agents) may be used in combination. Further, after completion of the acylation reaction, the degree of substitution may be adjusted by hydrolysis (saponification) as necessary. After completion of the reaction, the reaction mixture is separated using conventional means such as precipitation, washed and dried to obtain a mixed fatty acid ester of cellulose (for example, cellulose acetate propionate).

<Compound that suppresses permeability of acrylic curable adhesive>
In the present invention, as the compound that suppresses the permeability of the acrylic curable adhesive, specifically, a polyhydric alcohol ester having a structure represented by the following general formula (1) is preferable.

General formula (1)
B ₁ -G ₁ -B ₂
However, in the above general formula (1), B ₁ and B ₂ each independently represent an aliphatic monocarboxylic acid residue, or an aromatic monocarboxylic acid residue. G ₁ represents an alkylene glycol residue having a linear or branched structure having 2 to 12 carbon atoms.

In General Formula (1), G ₁ represents a divalent group derived from an alkylene glycol having a linear or branched structure having 2 to 12 carbon atoms.

Examples of the divalent group derived from an alkylene glycol having 2 to 12 carbon atoms in G ₁ include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propane Diol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3- Dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanedi Derived from all, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, etc. A divalent group can be mentioned. Two or more types of alkylene glycol can be preferably used in combination.

In the general formula (1), B ₁ and B ₂ are each independently a monovalent group derived from an aromatic ring-containing monocarboxylic acid or an aliphatic monocarboxylic acid.

  The aromatic ring-containing monocarboxylic acid in the monovalent group derived from the aromatic ring-containing monocarboxylic acid is a carboxylic acid containing an aromatic ring in the molecule, and not only those in which the aromatic ring is directly bonded to a carboxy group, Also included are those in which an aromatic ring is bonded to a carboxy group via an alkylene group or the like. Examples of monovalent groups derived from aromatic ring-containing monocarboxylic acids include benzoic acid, para-tert-butyl benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethyl benzoic acid, ethyl benzoic acid, normal propyl benzoic acid Monovalent groups derived from aminobenzoic acid, acetoxybenzoic acid, phenylacetic acid, 3-phenylpropionic acid, and the like. Of these, benzoic acid and p-toluic acid are preferable.

  Examples of monovalent groups derived from aliphatic monocarboxylic acids include monovalent groups derived from acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid and the like. Is included. Among these, a monovalent group derived from an alkyl monocarboxylic acid having 1 to 10 carbon atoms in the alkyl portion is preferable, and an acetyl group (a monovalent group derived from acetic acid) is more preferable.

  Specific examples of polyhydric alcohol esters applicable to the present invention are shown below, but the present invention is not limited to these exemplified compounds.

  The polyhydric alcohol ester having the structure represented by the general formula (1) according to the present invention can be synthesized according to a conventionally known general synthesis method.

  The content of the polyhydric alcohol ester having the structure represented by the general formula (1) is preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester forming the retardation film. More preferably, it is in the range of ˜3 parts by mass, and particularly preferably in the range of 1-2 parts by mass.

  In the present invention, an acrylic curable adhesive is produced by adding a polyhydric alcohol having a structure represented by the general formula (1) to the cellulose ester within the above range to produce a retardation film. Since it can suppress osmosis | permeation to the retardation film which concerns on this, favorable adhesiveness can be obtained.

  In the retardation film according to the present invention, when 4-hydroxydibutyl acrylate is used as a test liquid for evaluating the permeability of the acrylic curable adhesive, the test liquid is at 50 ° C. for 30 seconds. It is preferable that the polyhydric alcohol ester has a penetration depth into the cellulose ester film of 0.1 to 1.0 μm.

  The permeability evaluation of the acrylic curable adhesive into the retardation film can be performed with 4-hydroxydibutyl acrylate (hereinafter, also referred to as “4HBA”) as a test solution in place of the acrylic curable adhesive. .

In the present invention, the penetration depth of 4HBA from the film surface after 30 seconds at 50 ° C. is within the range of 0.1 to 1.0 μm using the 4HBA test solution. More preferably, it exists in the range of 0.3-0.6 micrometer. In the present invention, by adding the aforementioned polyhydric alcohol ester to the cellulose ester, an acrylic curable adhesive having a penetration depth into the cellulose ester film when the 4HBA test solution is used is within the above range. Therefore, it can be judged that good adhesion can be obtained. In addition, the acrylic curable adhesive can obtain stronger adhesiveness when it penetrates to the penetration depth.
The invention of the present application has improved the adhesiveness by reducing the penetration depth as compared with the film containing no compound that suppresses penetration, and confirmed that the penetration depth of 1.0 μm or less is effective. Yes. The lower limit of 0.1 μm could be confirmed by experiments up to 0.1 μm, but less than 0.1 μm is a region not obtained by experiments and has not been confirmed. Therefore, in the claims, the present invention is within the range of 0.1 to 1.0 μm in which the effectiveness has been confirmed.

  The penetration depth of the acrylic curable adhesive into the film can be measured by the following method.

(Measurement method of penetration depth into film)
100 parts by mass of 4HBA, 3 parts by mass of “Irgacure 819” (manufactured by BASF Japan) as a polymerization initiator were mixed, stirred at 50 ° C. for 1 hour, and a penetration depth measurement test solution (acrylic curable adhesive) Test solution) was obtained. Thereafter, the test liquid for measurement was heated to 50 ° C. and uniformly applied to an optical film with a thickness of 2.0 μm. After 30 seconds from the application, “Light HAMMER 10 (gallium-encapsulated metal halide lamp) was used as an irradiation device. ) ”(Fusion UV Systems, Inc.) was used to irradiate ultraviolet rays under the following conditions to cure the adhesive layer. The irradiation conditions are as follows: bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated irradiation amount (integrated light amount): 1000 mJ / cm ² (wavelength 380 to 440 nm).

  Thereafter, the laminated film provided with the adhesive layer is measured by observing the penetration depth of the test solution by cross-sectional observation measurement using a transmission electron microscope (TEM).

<Compound having a 5-membered or 6-membered aromatic heterocyclic group>
The resin composition forming the retardation film according to the present invention is a compound having a 5-membered or 6-membered aromatic heterocyclic group in addition to a compound that suppresses penetration of at least a cellulose ester and an acrylic curable adhesive (hereinafter referred to as “a compound”). , “Also referred to as an aromatic heterocyclic compound”).

  Examples of the 5- or 6-membered aromatic heterocyclic group include a furan ring group, a thiophene ring group, a pyrrole ring group, a pyrazole ring group, an imidazole ring group, an oxazole ring group, and a 1,2,4-oxadiazole ring. Group, 1,3,4-oxadiazole ring group, isoxazole ring group, thiazole ring group, 1,2,4-thiadiazole ring group, 1,3,4-thiadiazole ring group, isothiazole ring group, 1, Examples include 2,3-triazole ring group, 1,2,4-triazole ring group, pyridine ring group, pyrazine ring group, pyridazine ring group, pyrimidine ring group, triazine ring group and the like.

  Of these, a 5- or 6-membered aromatic heterocyclic group having at least one nitrogen atom is preferable, a 5-membered aromatic heterocyclic group having at least one nitrogen atom is preferable, and a 1,2,4-triazole ring. Groups are preferred.

  Since a compound having an aromatic heterocyclic group has a polarized π electron, it interacts strongly with the hydrogen atom of the resin and coordinates more strongly with the resin than with the water molecule. It is considered that the fluctuation of the phase difference value is suppressed. In particular, a compound having a 1,2,4-triazole ring not only strongly coordinates with a resin, but also has a strong interaction force with water molecules, and resin / 1,2,4-triazole-based compounds / water molecules are Since it is considered to have a stable structure, it is preferable because it is particularly excellent in suppressing the fluctuation of the retardation value.

  The retardation film according to the present invention particularly preferably contains a compound having a structure represented by the following general formula (2) as a compound having a 5-membered or 6-membered aromatic heterocyclic group.

In the above general formula (2), A ₁ and A ₂ are each independently an alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group, etc.) Cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), aromatic hydrocarbon ring group (phenyl group, p-tolyl group, naphthyl group, etc.), aromatic heterocyclic group (2-pyrrole) Group, 2-furyl group, 2-thienyl group, pyrrole group, imidazolyl group, oxazolyl group, thiazolyl group, benzimidazolyl group, benzoxazolyl group, 2-benzothiazolyl group, pyrazolinone group, pyridyl group, pyridinone group, 2-pyrimidinyl Group).

The alkyl group, cycloalkyl group, aromatic hydrocarbon ring group and aromatic heterocyclic group represented by A ₁ and A ₂ may have a substituent. Examples of the substituent include a halogen atom ( Fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl Group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group, etc.), cycloalkenyl group (2-cyclopenten-1-yl, 2-cyclohexen-1-yl group, etc.) ), Alkynyl group (ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (phenyl group, p-tolyl group, naphthyl group, etc.), aromatic heterocycle (2-pyrrole group, 2-furyl group, 2-thienyl group, pyrrole group, imidazolyl group, oxazolyl group, thiazolyl group, benzimidazolyl group, benzoxazolyl group, 2-benzothiazolyl group, pyrazolinone group, pyridyl group, pyridinone group 2-pyrimidinyl group, triazine group, pyrazole group, 1,2,3-triazole group, 1,2,4-triazole group, oxazole group, isoxazole group, 1,2,4-oxadiazole group, 1, 3,4-oxadiazole group, thiazole group, isothiazole group, 1,2,4-thiadiazole group, 1,3,4-thiadiazole group, etc.), cyano group, hydroxy group, nitro group, carboxy group, alkoxy group (Methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2 -Methoxyethoxy group, etc.), aryloxy groups (phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), acyloxy groups (formyloxy) Group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group, etc.), amino group (amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group) , Diphenylamino groups, etc.), acylamino groups (formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group, etc.), alkyl and arylsulfonylamino groups (methylsulfonylamino group, butylsulfonylamino group, Nylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group, etc.), mercapto group, alkylthio group (methylthio group, ethylthio group, n-hexadecylthio group etc.), arylthio group (phenylthio group) Group, p-chlorophenylthio group, m-methoxyphenylthio group, etc.), sulfamoyl group (N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N- (N′-phenylcarbamoyl) sulfamoyl group, etc.), sulfo group, acyl group (acetyl group, pivaloylbenzoyl group, etc.), carbamoyl group ( Carbamoyl group, N-methylcarbamoyl group, N, - dimethylcarbamoyl group, N, N-di -n- octylcarbamoyl group, and each group such as N- (methylsulfonyl) carbamoyl group).

In the general formula (2), A ₁ and A ₂ are each an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and can easily interact with the cellulose derivative. This is preferable because fluctuation is suppressed.

  In the general formula (2), B represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring.

  The aromatic hydrocarbon ring represented by B may be a single ring or a condensed ring. Preferred examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring, etc. More preferably, it is a benzene ring.

  The aromatic heterocycle represented by B is preferably a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxazole ring, 1, 2, 4-oxadiazole ring, 1,3,4-oxadiazole ring, isoxazole ring, thiazole ring, 1,2,4-thiadiazole ring, 1,3,4-thiadiazole ring, isothiazole ring, indole ring, A carbazole ring, an azacarbazole ring (an azacarbazole ring means one or more carbon atoms constituting the carbazole ring replaced by a nitrogen atom), a 1,2,3-triazole ring, 1,2,4- Triazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, flopi Ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzothiazole ring, benzoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, Isoquinoline ring, sinoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, azulene ring, silole ring, dibenzofuran ring, dibenzothiophene ring, dibenzocarbazole ring, benzodifuran ring, benzodithiophene Ring, phenanthroline ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, cyclazine ring, kindlin ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, trif Nojiokisajin ring, Fenantorajin ring, Antorajin ring, perimidine ring, Nafutofuran ring, naphthaldehyde thiophene ring, Nafutojifuran ring, naphthodifuran thiophene ring, Antorafuran ring, anthradithiophene furan ring, include anthracycline thiophene ring and the like. Of these, a pyridine ring and the like are more preferable.

In the general formula (2), the aromatic hydrocarbon ring or aromatic heterocycle represented by B may have a substituent, and examples of the substituent include A ₁ and A ₂ in the general formula (2). The group similar to the substituent which you may have can be mentioned.

In the general formula (2), T ₁ and T ₂ each independently represents a 1,2,4-triazole ring. The 1,2,4-triazole ring represented by T ₁ and T ₂ may be a tautomer. Specifically, any of the following structures represents a 1,2,4-triazole ring.

(In the above formula, * represents a bonding position with L ₁ , L ₂ , L ₃ or L _4. R ₁ represents a hydrogen atom or a substituent. The substituent represented by R ₁ includes the above-mentioned general formula. include the same groups as the substituent that may be possessed by a ₁ in (2) .R ₁ is hydrogen atom is preferably an alkyl group or an acyl group.)
In the general formula (2), T ₁ and T ₂ may have a substituent, and examples of the substituent include the substituent that A ₁ and A ₂ in the general formula (2) may have Similar groups can be mentioned.

In the general formula (2), L ₁ , L ₂ , L ₃ and L ₄ each independently represent a single bond or a divalent linking group. Specific examples of the divalent linking group include an alkylene group, an alkenylene group, an alkynylene group, O, (C═O), (C═O) —O, NR, S, and (O═S═O). It represents a divalent linking group selected from the group consisting of these or a combination thereof. R represents a hydrogen atom or a substituent. Examples of the substituent represented by R include an alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl group ( Cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), aromatic hydrocarbon ring group (phenyl group, p-tolyl group, naphthyl group, etc.), aromatic heterocyclic group (2-furyl group, 2-thienyl group). Group, 2-pyrimidinyl group, 2-benzothiazolyl group, 2-pyridyl group, etc.), cyano group and the like. The divalent linking group represented by L ₁ , L ₂ , L ₃ and L ₄ may have a substituent, and the substituent is not particularly limited. For example, A in the general formula (2) and ₁ and a ₂ have include the same groups as also substituents.

In the general formula (2), L ₁ , L ₂ , L ₃ and L ₄ can interact with the cellulose derivative by increasing the planarity of the compound having the structure represented by the general formula (2). Since the fluctuation of the phase difference value according to the change in environmental humidity is suppressed, a single bond, O, (C═O) —O, O— (C═O), (C═O) —NR or NR- (C = O) is preferable, and a single bond is more preferable.

In the said General formula (2), n represents the integer of 0-5. When n represents an integer of 2 or more, the plurality of A ₂ , T ₂ , L ₃ and L ₄ in the general formula (2) may be the same or different. A larger n is preferable because the compound having the structure represented by the general formula (2) is more likely to interact with the cellulose derivative, so that fluctuations in optical values with respect to changes in environmental humidity are suppressed. When it becomes too much, compatibility with a cellulose ester will worsen. For this reason, it is preferable that n is an integer of 1-5, and it is more preferable that it is an integer of 1-4.

  The compound having a structure represented by the general formula (2) is preferably a compound having a structure represented by the following general formula (3).

In the above general formula (3), A ₁ , A ₂ , T ₁ , T ₂ , L ₁ , L ₂ , L ₃ and L ₄ are respectively A ₁ , A ₂ , T ₁ , T _{2, L} 1, is synonymous with L 2, _{L 3} and _{L 4.} A ₃ and T ₃ represent the same groups as A ₁ and T ₁ in the general formula (2), respectively. L ₅ and L ₆ represent the same group as L ₁ in the general formula (2). Q ₁ , Q ₂ , Q ₃ and Q ₄ represent a carbon atom or a nitrogen atom. m represents an integer of 0 to 4.
Since the smaller m is excellent in compatibility with the cellulose ester, m is more preferably an integer of 0 to 3.

  The compound having the structure represented by the general formula (2) may form a hydrate, a solvate or a salt. In the present invention, the hydrate may contain an organic solvent, and the solvate may contain water. That is, “hydrate” and “solvate” include mixed solvates containing both water and organic solvents. Salts include acid addition salts formed with inorganic or organic acids. Examples of inorganic acids include, but are not limited to, hydrohalic acids (hydrochloric acid, hydrobromic acid, etc.), sulfuric acid, phosphoric acid, and the like. Examples of organic acids include acetic acid, trifluoroacetic acid, propionic acid, butyric acid, oxalic acid, citric acid, benzoic acid, alkyl sulfonic acid (such as methane sulfonic acid), allyl sulfonic acid (benzene sulfonic acid, 4-toluene) Sulfonic acid, 1,5-naphthalenedisulfonic acid, etc.) and the like. Of these, hydrochloride, acetate, propionate and butyrate are preferable.

  Examples of salts include acidic moieties present in the parent compound that are metal ions (eg, alkali metal salts such as sodium or potassium salts, alkaline earth metal salts such as calcium or magnesium salts, ammonium salts, alkali metal ions, alkaline earths). Salts formed by substitution with organic bases (such as ethanolamine, diethanolamine, triethanolamine, morpholine, piperidine), and the like. It is not limited. Of these, sodium salts and potassium salts are preferred.

  Examples of the solvent included in the solvate include any common organic solvent. Specifically, alcohol (eg, methanol, ethanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, t-butanol), ester (eg, ethyl acetate), hydrocarbon (eg, toluene, hexane) , Heptane), ether (eg, tetrahydrofuran), nitrile (eg, acetonitrile), ketone (eg, acetone) and the like. Preferably, it is a solvate of alcohol (eg, methanol, ethanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, t-butanol). These solvents may be a reaction solvent used at the time of synthesizing the compound, a solvent used at the time of crystallization purification after synthesis, or a mixture thereof.

  Two or more kinds of solvents may be included at the same time, or a form containing water and a solvent (for example, water and alcohol (for example, methanol, ethanol, t-butanol, etc.), etc.).

  In addition, even if the compound having the structure represented by the general formula (2) is added in a form not containing water, a solvent, or a salt, in the resin composition or the optical film according to the present invention, a hydrate, Solvates or salts may be formed.

  The molecular weight of the compound having the structure represented by the general formula (2) is not particularly limited. It is preferable that it is 150-2000, It is more preferable that it is 200-1500, It is more preferable that it is 300-1000.

  Specific examples of the compound having the structure represented by the general formula (2) are shown below, but the compound having the structure represented by the general formula (2) that can be used in the present invention includes the following specific examples. There is no limitation by example. As described above, the following specific examples may be tautomers, and may form hydrates, solvates or salts.

(Synthesis method)
Next, a method for synthesizing the compound having the structure represented by the general formula (2) will be described.
The compound having the structure represented by the general formula (2) may use any raw material, but a method of reacting a nitrile derivative or imino ether derivative with a hydrazide derivative is preferable. The solvent used in the reaction may be any solvent as long as it does not react with the raw material, but may be an ester type (eg, ethyl acetate, methyl acetate, etc.), an amide type (eg, dimethylformamide, dimethylacetamide, etc.), Ether type (for example, ethylene glycol dimethyl ether), alcohol type (for example, methanol, ethanol, propanol, isopropanol, n-butanol, 2-butanol, ethylene glycol, ethylene glycol monomethyl ether, etc.), aromatic hydrocarbon type (for example, Toluene, xylene, etc.) and water. As a solvent to be used, an alcohol solvent is preferable. These solvents may be used as a mixture.

  Although there is no restriction | limiting in particular in the usage-amount of a solvent, It is preferable to exist in the range of 0.5-30 times amount with respect to the mass of the hydrazide derivative to be used, More preferably, it is 1.0-25 times amount. Yes, particularly preferably within the range of 3.0 to 20 times the amount.

  When reacting a nitrile derivative and a hydrazide derivative, it is not necessary to use a catalyst, but it is preferable to use a catalyst in order to accelerate the reaction. As a catalyst to be used, an acid may be used and a base may be used. Examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, acetic acid and the like, preferably hydrochloric acid. The acid may be added after diluted in water, or may be added by a method of blowing a gas into the system. Bases include inorganic bases (potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate, potassium hydroxide, sodium hydroxide, etc.) and organic bases (sodium methylate, sodium ethylate, potassium methylate, potassium ethylate, Sodium butyrate, potassium butyrate, diisopropylethylamine, N, N′-dimethylaminopyridine, 1,4-diazabicyclo [2.2.2] octane, N-methylmorpholine, imidazole, N-methylimidazole, pyridine, etc.) Any of them may be used, and the inorganic base is preferably potassium carbonate, and the organic base is preferably sodium ethylate, sodium ethylate or sodium butyrate. The inorganic base may be added as a powder or may be added in a state dispersed in a solvent. The organic base may be added in a state dissolved in a solvent (for example, a 28% methanol solution of sodium methylate).

  Although there will be no restriction | limiting in particular if the usage-amount of a catalyst is the quantity which reaction advances, The inside of the range of 1.0-5.0 times mole with respect to the triazole ring formed is preferable, and also 1.05-3. A range of 0-fold mole is preferable.

  When the imino ether derivative and the hydrazide derivative are reacted, it is not necessary to use a catalyst, and the target product can be obtained by heating in a solvent.

  The addition method of the raw material, solvent, and catalyst used for the reaction is not particularly limited, and the catalyst may be added last, or the solvent may be added last. Also preferred is a method of dispersing or dissolving a nitrile derivative in a solvent, adding a catalyst, and then adding a hydrazide derivative.

  The solution temperature during the reaction may be any temperature as long as the reaction proceeds, but is preferably in the range of 0 to 150 ° C, more preferably in the range of 20 to 140 ° C. Moreover, you may react, removing the water to produce | generate.

  Any means may be used as a method for treating the reaction solution, but when a base is used as a catalyst, a method of neutralizing the reaction solution by adding an acid is preferable. Examples of the acid used for neutralization include hydrochloric acid, sulfuric acid, nitric acid, and acetic acid. Acetic acid is particularly preferable. The amount of acid used for neutralization is not particularly limited as long as the pH of the reaction solution is in the range of 4 to 9, but is preferably 0.1 to 3 moles, particularly preferably, relative to the base used. , Within a range of 0.2 to 1.5 moles.

  As a method for treating the reaction solution, when extracting using a suitable organic solvent, a method of washing the organic solvent with water after extraction and then concentrating is preferable. The appropriate organic solvent here is a water-insoluble solvent such as ethyl acetate, toluene, dichloromethane, ether, or a mixed solvent of the water-insoluble solvent and tetrahydrofuran or an alcohol solvent, preferably Ethyl acetate.

  When the compound having the structure represented by the general formula (2) is crystallized, there is no particular limitation, but a method of crystallizing by adding water to the neutralized reaction solution, or represented by the general formula (2) A method in which an aqueous solution in which a compound having a structure is dissolved is neutralized and crystallized is preferable.

(Synthesis of Exemplified Compound H-1)
Illustrative compound H-1 can be synthesized by the following scheme.

  To 350 ml of n-butanol, 77.3 g (75.0 mmol) of benzonitrile, 34.0 g (25.0 mmol) of benzoylhydrazine and 107.0 g (77.4 mmol) of potassium carbonate were added and stirred at 120 ° C. for 24 hours under a nitrogen atmosphere. did. The reaction solution was cooled to room temperature, the precipitate was filtered, and the filtrate was concentrated under reduced pressure. 20 ml of isopropanol was added to the concentrate, and the precipitate was collected by filtration. The precipitate collected by filtration was dissolved in 80 ml of methanol, 300 ml of pure water was added, and acetic acid was added dropwise until the pH of the solution reached 7. The precipitated crystals were collected by filtration, washed with pure water, and blown dry at 50 ° C. to obtain 38.6 g of Exemplified Compound H-1. The yield was 70% based on benzoylhydrazine.

The ¹ H-NMR spectrum of the obtained exemplary compound H-1 is as follows.

¹ H-NMR (400 MHz, solvent: heavy DMSO, standard: tetramethylsilane) δ (ppm): 7.56-7.48 (6H, m), 7.62-7.61 (4H, m)

(Synthesis of Exemplified Compound H-6)
Illustrative compound H-6 can be synthesized according to the following scheme.

  To 40 ml of n-butanol, 2.5 g (19.5 mmol) of 1,3-dicyanobenzene, 7.9 g (58.5 mmol) of benzoylhydrazine and 9.0 g (68.3 mmol) of potassium carbonate were added, and the temperature was 120 ° C. under a nitrogen atmosphere. For 24 hours. After cooling the reaction solution, 40 ml of pure water was added and stirred at room temperature for 3 hours, and then the precipitated solid was filtered off and washed with pure water. Water and ethyl acetate were added to the obtained solid for liquid separation, and the organic layer was washed with pure water. The organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The resulting crude crystals were purified by silica gel chromatography (ethyl acetate / heptane) to obtain 5.5 g of exemplary compound H-6. The yield was 77% based on 1,3-dicyanobenzene.

The ¹ H-NMR spectrum of the obtained exemplary compound H-6 is as follows.

¹ H-NMR (400 MHz, solvent: heavy DMSO, standard: tetramethylsilane) δ (ppm): 8.83 (1H, s), 8.16-8.11 (6H, m), 7.67-7 .54 (7H, m)
Other compounds can be synthesized by the same method.

(About the usage method of the compound which has a structure represented by General formula (2))
The compound having the structure represented by the general formula (2) according to the present invention can be contained in the optical film by adjusting the amount as appropriate, and the addition amount forms the retardation film according to the present invention. It is preferable that it is 1-10 mass parts with respect to 100 mass parts of cellulose ester to perform, and it is preferable to contain 2-10 mass parts especially. If it is in this range, the fluctuation of the optical value depending on the change of the environmental humidity can be reduced without impairing the mechanical strength of the retardation film according to the present invention.

  In addition, as a method for adding the compound having the structure represented by the general formula (2), it may be added as a powder to a resin forming a retardation film, and after dissolving in a solvent, an optical film is formed. It may be added to the resin.

<Sugar ester>
The retardation film according to the present invention preferably contains a sugar ester other than cellulose ester. By containing a sugar ester, the effect of plasticizing the cellulose ester can be obtained.

  In this invention, it is preferable to add 1-20 mass parts of sugar ester with respect to 100 mass parts of cellulose esters from a viewpoint of expressing the said effect.

  The sugar ester used in the retardation film according to the present invention is a sugar ester in which at least one pyranose ring or furanose ring is 1 to 12 and all or part of the OH groups of the structure are esterified. Preferably there is.

  The sugar ester is a compound containing at least one of a furanose ring and a pyranose ring, and may be a monosaccharide or a polysaccharide having 2 to 12 sugar structures linked together. The sugar ester is preferably a compound in which at least one OH group of the sugar structure is esterified. In the sugar ester according to the present invention, the average ester substitution degree is more preferably in the range of 5.0 to 7.5.

  Although there is no restriction | limiting in particular as sugar ester applicable to this invention, The sugar ester which has a structure represented by following General formula (4) can be mentioned.

General formula (4)
_{(HO) m -G- (O-} C (= O) -R 2) n
In the general formula (4), G represents a monosaccharide or disaccharide residue, R ₂ represents an aliphatic group or an aromatic group, and m is directly bonded to the monosaccharide or disaccharide residue. N is the total number of — (O—C (═O) —R ₂ ) groups directly bonded to the monosaccharide or disaccharide residue, 3 ≦ m + n ≦ 8, and n ≠ 0.

The sugar ester having the structure represented by the general formula (4) is a single kind of hydroxy group (m) and-(O—C (═O) —R ₂ ) group in which the number (n) is fixed. It is difficult to isolate as a compound, and it is known that a compound in which several components different in m and n in the formula are mixed is obtained. Therefore, the performance as a mixture in which the number (m) of hydroxy groups and the number (n) of-(O—C (═O) —R ₂ ) groups are important is important. A sugar ester having an average ester substitution degree in the range of 5.0 to 7.5 is preferable.

  In the general formula (4), G represents a monosaccharide or disaccharide residue. Specific examples of monosaccharides include allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose, lyxose, and the like.

  Specific examples of the compound having a monosaccharide residue of a sugar ester having a structure represented by the general formula (4) are shown below, but the present invention is not limited to these exemplified compounds.

  Specific examples of the disaccharide residue include trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, and isotrehalose.

  Specific examples of the compound having a disaccharide residue of a sugar ester having a structure represented by the general formula (4) are shown below, but the present invention is not limited to these exemplified compounds.

In general formula (4), R ₂ represents an aliphatic group or an aromatic group. Here, the aliphatic group and the aromatic group may each independently have a substituent.

In the general formula (4), m is the total number of hydroxy groups directly bonded to the monosaccharide or disaccharide residue, and n is directly bonded to the monosaccharide or disaccharide residue. The total number of — (O—C (═O) —R ₂ ) groups. Further, it is necessary that 3 ≦ m + n ≦ 8, and it is preferable that 4 ≦ m + n ≦ 8. Further, n ≠ 0. When n is 2 or more, the — (O—C (═O) —R ₂ ) groups may be the same as or different from each other.

The aliphatic group in the definition of R ₂ may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 1 to 20 carbon atoms. Two to fifteen are preferred. Specific examples of the aliphatic group include, for example, methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, iso-butyl, tert-butyl, amyl, iso-amyl, tert-amyl, n- Examples include hexyl, cyclohexyl, n-heptyl, n-octyl, bicyclooctyl, adamantyl, n-decyl, tert-octyl, dodecyl, hexadecyl, octadecyl, didecyl and the like.

The aromatic group in the definition of R ₂ may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. As the aromatic hydrocarbon group, those having 6 to 24 carbon atoms are preferable, and those having 6 to 12 carbon atoms are more preferable. Specific examples of the aromatic hydrocarbon group include rings such as benzene, naphthalene, anthracene, biphenyl, and terphenyl. As the aromatic hydrocarbon group, a benzene ring, a naphthalene ring, and a biphenyl ring are particularly preferable. As the aromatic heterocyclic group, a ring containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom is preferable. Specific examples of the heterocyclic ring include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, Examples of the ring include isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, and tetrazaindene. As the aromatic heterocyclic group, a pyridine ring, a triazine ring, and a quinoline ring are particularly preferable.

  Next, although the preferable example of the sugar ester which has a structure represented by General formula (4) is shown below, this invention is not limited to these illustrated compounds.

  A sugar ester may contain two or more different substituents in one molecule, contains an aromatic substituent and an aliphatic substituent in one molecule, and contains two or more different aromatic substituents. Two or more different aliphatic substituents contained in one molecule can be contained in one molecule. It is also preferable to contain a mixture of two or more sugar esters. It is also preferable to simultaneously contain a sugar ester containing an aromatic substituent and a sugar ester containing an aliphatic substituent.

(Synthesis Example: Synthesis Example of Sugar Ester Having Structure Represented by General Formula (4))
Below, an example of the synthesis | combination of the sugar ester which can be used suitably for this invention is shown.

Four-headed Kolben equipped with a stirrer, reflux condenser, thermometer and nitrogen gas inlet tube, 34.2 g (0.1 mol) of sucrose, 180.8 g (0.8 mol) of benzoic anhydride, pyridine 379.7 g (4.8 mol) of each were charged, and the temperature was raised while bubbling nitrogen gas from a nitrogen gas inlet tube under stirring, and esterification was carried out at 70 ° C. for 5 hours. Next, the inside of the Kolben was depressurized to 4 × 10 ² Pa or less, and after excess pyridine was distilled off at 60 ° C., the inside of the Kolben was depressurized to 1.3 × 10 Pa or less and the temperature was raised to 120 ° C. Most of the acid and benzoic acid formed were distilled off. Then, 1 L of toluene and 300 g of a 0.5% by mass sodium carbonate aqueous solution were added, and the mixture was stirred at 50 ° C. for 30 minutes, and then allowed to stand to separate a toluene layer. Finally, 100 g of water was added to the separated toluene layer, and after washing with water at room temperature for 30 minutes, the toluene layer was separated, and toluene was distilled off at 60 ° C. under reduced pressure (4 × 10 ² Pa or less). The mixture of exemplary compound A-1, A-2, A-3, A-4, and A-5 was obtained. When the obtained mixture was analyzed by HPLC and LC-MASS, A-1 was 7% by mass, A-2 was 58% by mass, A-3 was 23% by mass, A-4 was 9% by mass, A-5. Was 3% by mass, and the average ester substitution degree of the sugar ester was 6.57. In addition, Example Compound A-1, A-2, A-3, A-4, and A-5 of 100% purity were obtained by refine | purifying a part of obtained mixture by silica gel column chromatography, respectively.

<Other additives>
In the retardation film according to the present invention, conventionally known additives can be used as long as the effects of the present invention are not impaired.

  Hereinafter, typical other additives will be described.

(polyester)
In the present invention, polyesters other than sugar esters can be used as one of the plasticizers.

  Although there is no restriction | limiting in particular as polyester other than sugar ester applicable to this invention, The polyester compound which has a structure represented by following General formula (5) can be used.

  From the plastic effect, the polyester is preferably contained in the range of 1 to 20% by mass, and more preferably in the range of 2 to 10% by mass in the retardation film according to the present invention.

General formula (5)
B _1- (G ₁ -A) _n -G ₁ -B ₂
In the general formula (5), B ₁ and B ₂ each independently represent an aliphatic or aromatic monocarboxylic acid residue. G ₁ represents an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms. A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms. n represents an integer of 1 or more.

In the present invention, the polyester is a polyester containing a repeating unit obtained by reacting a dicarboxylic acid and a diol, A represents a carboxylic acid residue in the ester, and G ₁ represents an alcohol residue.

  The dicarboxylic acid constituting the polyester is an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid, preferably an aromatic dicarboxylic acid. The dicarboxylic acid may be one type or a mixture of two or more types. In particular, it is preferable to mix aromatic and aliphatic.

  The diol constituting the polyester is an aromatic diol, an aliphatic diol or an alicyclic diol, preferably an aliphatic diol, and more preferably a diol having 1 to 4 carbon atoms. The diol may be one type or a mixture of two or more types.

  Among them, it is preferable to include a repeating unit obtained by reacting at least a dicarboxylic acid containing an aromatic dicarboxylic acid and a diol having 1 to 8 carbon atoms, and includes an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid. More preferably, it contains a repeating unit obtained by reacting a dicarboxylic acid with a diol having 1 to 8 carbon atoms.

  Both ends of the polyester molecule may be sealed or not sealed, but from the viewpoint of reducing the retardation value fluctuation of the protective film against temperature and humidity fluctuations, it may be sealed. preferable.

  Specific examples of the alkylene dicarboxylic acid constituting A in the general formula (5) include 1,2-ethanedicarboxylic acid (succinic acid), 1,3-propanedicarboxylic acid (glutaric acid), and 1,4-butanedicarboxylic acid. Divalent groups derived from (adipic acid), 1,5-pentanedicarboxylic acid (pimelic acid), 1,8-octanedicarboxylic acid (sebacic acid) and the like are included. Specific examples of the alkenylene dicarboxylic acid constituting A include maleic acid and fumaric acid. Specific examples of the aryl dicarboxylic acid constituting A include 1,2-benzenedicarboxylic acid (phthalic acid), 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and the like. Can be mentioned.

  A may be one type or two or more types may be combined. Among these, A is preferably a combination of an alkylene dicarboxylic acid having 4 to 12 carbon atoms and an aryl dicarboxylic acid having 8 to 12 carbon atoms.

G ₁ in the general formula (5) is a divalent group derived from an alkylene glycol having 2 to 12 carbon atoms, a divalent group derived from an aryl glycol having 6 to 12 carbon atoms, or Represents a divalent group derived from an oxyalkylene glycol having 4 to 12 carbon atoms.

Examples of the divalent group derived from an alkylene glycol having 2 to 12 carbon atoms in G ₁ include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propane Diol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3- Dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanedi Derived from all, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, etc. Divalent groups are included.

Examples of the divalent group derived from an aryl glycol having 6 to 12 carbon atoms in G ₁ include 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol), 1,4- Divalent groups derived from dihydroxybenzene (hydroquinone) and the like are included. Examples of divalent groups derived from oxyalkylene glycols having 4 to 12 carbon atoms in G ₁ are derived from diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol and the like. Divalent groups are included.

G ₁ may be one type or two or more types may be combined. Among them, _{G 1} is preferably a carbon atom number from 2 to 12 alkylene glycol.

B ₁ and B ₂ in the general formula (5) are each a monovalent group derived from an aromatic ring-containing monocarboxylic acid or an aliphatic monocarboxylic acid.

  The aromatic ring-containing monocarboxylic acid in the monovalent group derived from the aromatic ring-containing monocarboxylic acid is a carboxylic acid containing an aromatic ring in the molecule, and not only those in which the aromatic ring is directly bonded to a carboxy group, Also included are those in which an aromatic ring is bonded to a carboxy group via an alkylene group or the like. Examples of monovalent groups derived from aromatic ring-containing monocarboxylic acids include benzoic acid, para-tert-butyl benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethyl benzoic acid, ethyl benzoic acid, normal propyl benzoic acid Monovalent groups derived from aminobenzoic acid, acetoxybenzoic acid, phenylacetic acid, 3-phenylpropionic acid, and the like. Of these, benzoic acid and p-toluic acid are preferable.

  Examples of monovalent groups derived from aliphatic monocarboxylic acids include monovalent groups derived from acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid and the like. Is included. Among these, a monovalent group derived from an alkyl monocarboxylic acid having 1 to 3 carbon atoms in the alkyl portion is preferable, and an acetyl group (a monovalent group derived from acetic acid) is more preferable.

  The weight average molecular weight Mw of the polyester according to the present invention is preferably in the range of 500 to 3000, and more preferably in the range of 600 to 2000. The weight average molecular weight can be measured by the gel permeation chromatography (GPC).

  Hereinafter, although the specific example of polyester which has a structure represented by General formula (5) is shown, it is not limited to this.

  Hereinafter, specific synthesis examples of the polyester described above will be described.

(Synthesis of polyester P1)
180 g of ethylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer and a reflux condenser. The temperature is gradually raised with stirring until reaching 230 ° C. in a nitrogen stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. Polyester P1 was obtained by depressurizingly distilling unreacted ethylene glycol at 200 degreeC after completion | finish of reaction. The acid value was 0.20 and the weight average molecular weight was 450.

(Synthesis of polyester P2)
251 g of 1,2-propylene glycol, 244 g of phthalic anhydride, 103 g of adipic acid, 610 g of benzoic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst, 4 L of 2 L equipped with a thermometer, a stirrer and a reflux condenser The flask is charged and gradually heated with stirring until it reaches 230 ° C. in a nitrogen stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 ° C. to obtain polyester P2. The acid value was 0.10 and the weight average molecular weight was 450.

(Synthesis of polyester P3)
1,4-butanediol (330 g), phthalic anhydride (244 g), adipic acid (103 g), benzoic acid (610 g), tetraisopropyl titanate (0.191 g) as an esterification catalyst, thermometer, stirrer, reflux condenser and 2 L four-neck The flask is charged and gradually heated with stirring until it reaches 230 ° C. in a nitrogen stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,4-butanediol was distilled off at 200 ° C. under reduced pressure to obtain polyester P3. The acid value was 0.50 and the weight average molecular weight was 2000.

(Synthesis of polyester P4)
251 g of 1,2-propylene glycol, 354 g of terephthalic acid, 610 g of benzoic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, The temperature is gradually raised with stirring until it reaches 230 ° C. in an air stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, polyester P4 was obtained by distilling off unreacted 1,2-propylene glycol at 200 ° C. under reduced pressure. The acid value was 0.10 and the weight average molecular weight was 400.

(Synthesis of polyester P5)
251 g of 1,2-propylene glycol, 354 g of terephthalic acid, 680 g of p-troyl acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst are charged into a 2 L four-necked flask equipped with a thermometer, a stirrer and a reflux condenser. The temperature is gradually raised with stirring until it reaches 230 ° C. in a nitrogen stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off at 200 ° C. under reduced pressure to obtain polyester P5. The acid value was 0.30 and the weight average molecular weight was 400.

(Synthesis of polyester P6)
180 g of 1,2-propylene glycol, 292 g of adipic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and in a nitrogen stream The temperature is gradually raised while stirring until 200 ° C is reached. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 ° C. to obtain polyester P6. The acid value was 0.10 and the weight average molecular weight was 400.

(Synthesis of polyester P7)
160 g of ethylene glycol, 292 g of adipic acid, and 0.191 g of tetraisopropyl titanate as an esterification catalyst are charged into a 2 L four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and become 200 ° C. in a nitrogen stream. Until the temperature is gradually increased. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted ethylene glycol was distilled off at 200 ° C. under reduced pressure to obtain polyester P7. The acid value was 0.10 and the weight average molecular weight was 1000.

(Synthesis of polyester P8)
251 g of ethylene glycol, 244 g of phthalic anhydride, 200 g of sebacic acid, 610 g of benzoic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer and a reflux condenser. The temperature is gradually raised with stirring until reaching 230 ° C. in a nitrogen stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. Polyester P8 was obtained by depressurizingly distilling unreacted ethylene glycol at 200 degreeC after completion | finish of reaction. The acid value was 0.50 and the weight average molecular weight was 2000.

(Phosphate compound)
In the present invention, a phosphate ester compound can be used. Examples of phosphate ester compounds include triaryl phosphate esters, diaryl phosphate esters, monoaryl phosphate esters, aryl phosphonic acid compounds, aryl phosphine oxide compounds, condensed aryl phosphate esters, halogenated alkyl phosphate esters, and halogen-containing condensed phosphorus compounds. Examples thereof include acid esters, halogen-containing condensed phosphonate esters, and halogen-containing phosphite esters.

  Specific phosphoric acid ester compounds include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris ( Dichloropropyl) phosphate, tris (tribromoneopentyl) phosphate, and the like.

(UV absorber)
The retardation film according to the present invention may contain an ultraviolet absorber from the viewpoint of improving light resistance. The ultraviolet absorber is intended to improve light resistance by absorbing ultraviolet rays of 400 nm or less, and in particular, the transmittance at a wavelength of 370 nm is preferably 10% or less, more preferably 5% or less, and further Preferably it is 2% or less.

  The ultraviolet absorber preferably used in the present invention is a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, or a triazine ultraviolet absorber, and particularly preferably a benzotriazole ultraviolet absorber or a benzophenone ultraviolet absorber.

  For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (linear and side Chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc., and tinuvin 109, tinuvin 171, tinuvin 234, tinuvin 326, tinuvin 327, tinuvin 328, There are tinuvins such as tinuvin 928, and these are all commercially available products from BASF Japan and can be preferably used. Of these, halogen-free ones are preferred.

  In addition, a discotic compound such as a compound having a 1,3,5-triazine ring is also preferably used as the ultraviolet absorber.

  The retardation film according to the present invention preferably contains two or more kinds of ultraviolet absorbers.

  As the UV absorber, a polymer UV absorber can also be preferably used, and in particular, a polymer type UV absorber described in JP-A-6-148430 is preferably used. Moreover, it is preferable that the ultraviolet absorber does not have a halogen group.

  The method of adding the UV absorber can be added to the dope after dissolving the UV absorber in an alcohol such as methanol, ethanol or butanol, an organic solvent such as methylene chloride, methyl acetate, acetone or dioxolane or a mixed solvent thereof. Or you may add directly in dope composition.

  For an inorganic powder that does not dissolve in an organic solvent, a dissolver or a sand mill is used in the organic solvent and cellulose ester (cellulose acetate) to disperse and then added to the dope.

  The amount of the UV absorber used is not uniform depending on the type of UV absorber, usage conditions, etc., but when the dry film thickness of the retardation film is 15-50 μm, it is 0.5-10 for the retardation film. The range of mass% is preferable, and the range of 0.6 to 4 mass% is more preferable.

(Antioxidant)
Antioxidants are also referred to as deterioration inhibitors. When an organic electroluminescence display device or the like is placed in a high humidity and high temperature state, the retardation film may be deteriorated.

  The antioxidant has a role of delaying or preventing the retardation film from being decomposed by, for example, the residual solvent amount of halogen in the retardation film or phosphoric acid of the phosphoric acid plasticizer. It is preferable to contain in such a retardation film.

  As such an antioxidant, a hindered phenol compound is preferably used. For example, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3 -(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino)- 1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octa Sil-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxy Benzyl) -isocyanurate and the like.

  In particular, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.

  The amount of these compounds to be added is preferably in the range of 1 ppm to 1.0% by mass and more preferably in the range of 10 to 1000 ppm with respect to the cellulose ester (cellulose acetate).

≪Method for producing retardation film≫
<< Method for producing cellulose ester film >>
Next, the manufacturing method of the cellulose-ester film used for the retardation film which concerns on this invention is demonstrated.

  The cellulose ester film according to the present invention can be preferably used regardless of whether it is a film produced by a solution casting method or a film produced by a melt casting method.

  The cellulose ester film according to the present invention is prepared 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. Is performed by a step of drying as a web, a step of peeling from a metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished film.

  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 ester (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.

  The recovery solvent may contain trace amounts of additives added to the cellulose ester, such as plasticizers, UV absorbers, polymers, monomer components, etc., but even if these are included, they are preferably reused. Can be purified and reused if necessary.

  A general method can be used as a method of dissolving 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 material called gel or mamako.

  Further, a method in which a cellulose ester is mixed with a poor solvent and wetted or swollen, and then a good solvent is added and dissolved is also preferably used.

  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 the 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 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 easily 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.

  The material of the filter medium is not particularly limited, and a normal filter medium can be used. However, a plastic filter medium such as polypropylene or Teflon (registered trademark) or a metal filter medium such as stainless steel is used for the fiber. It is preferable because there is no dropout.

  It is preferable to remove and reduce impurities, particularly bright spot foreign matter, contained in the raw material cellulose ester by filtration.

Bright spot foreign matter is when two polarizing plates are placed in a crossed Nicol state, an optical film or the like is placed between them, light is applied from the side of one polarizing plate, and observed from the side of the other polarizing plate 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 less than 0.01 mm 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 (called 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, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.

  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 at a higher speed. May deteriorate.

  A preferable support temperature is 0 to 55 ° C, and more preferably 25 to 50 ° C. 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 warm 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 cellulose ester film 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. Especially preferably, it is 20-30 mass% or 70-120 mass%.

  In the present invention, the amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  Further, in the drying step of the cellulose ester film, 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, Especially preferably, it is 0-0.01 mass% or less.

  In the film drying step, generally, a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.

  In order to produce the cellulose ester film according to the present invention, it is particularly preferable to perform stretching in the width direction (lateral direction) by a tenter method in which both ends of the web are held with clips or the like. Peeling is preferably performed at a peeling tension of 300 N / m or less.

  The means for drying the web 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.

  The drying temperature in the web drying step is preferably increased stepwise from 40 to 200 ° C.

  Although the film thickness of a cellulose-ester film is not specifically limited, 10-200 micrometers is used. In particular, the film thickness is particularly preferably 10 to 100 μm. More preferably, it is 20-60 micrometers.

  A cellulose ester film having a width of 1 to 4 m is used. In particular, those having a width of 1.4 to 4 m are preferably used, and particularly preferably 1.6 to 3 m. If it exceeds 4 m, conveyance becomes difficult.

《Phase difference value》
The retardation film according to the present invention can be used as a retardation film for VA. In the present invention, the retardation values Ro and Rt of the retardation film are preferably within the following ranges.

  That is, in the measurement wavelength 590 nm, 23 ° C. and 55% RH environment, the in-plane retardation value Ro is in the range of 40 nm ≦ | Ro | ≦ 100 nm, and the retardation value Rt in the film thickness direction is 100 nm ≦ | Rt | ≦ 300 nm is preferable.

  Within this range, the effect of widening the viewing angle can be obtained when a liquid crystal display device is obtained.

<Measurement of phase difference values Ro and Rt>
A sample of 35 mm × 35 mm was cut out from the obtained film, conditioned at 23 ° C. and 55% RH for 2 hours, and measured with an automatic birefringence meter (KOBRA21DH, Oji Scientific Instruments) from the vertical direction at 590 nm It is calculated from the extrapolated value of the retardation value measured in the same manner while tilting the film surface.

<Control method of phase difference value>
In order to obtain preferable retardation values Ro and Rt in the present invention, it is preferable that the cellulose ester film has the structure of the present invention, and the refractive index is controlled by controlling the transport tension and stretching.

  For example, it is possible to vary the phase difference value by lowering or increasing the tension in the longitudinal direction.

  In addition, the film can be sequentially or simultaneously biaxially or uniaxially stretched with respect to the longitudinal direction (film forming direction) of the film and the direction orthogonal to the longitudinal direction of the film, that is, the width direction.

  It is preferable that the draw ratios in the biaxial directions perpendicular to each other are finally in the range of 0.8 to 1.5 times in the casting direction and 1.1 to 2.5 times in the width direction. It is preferable to perform in the range of 0.8 to 1.0 times in the direction and 1.2 to 2.0 times in the width direction.

  The stretching temperature is preferably from 120 to 200 ° C, more preferably from 150 to 200 ° C, and further preferably from 150 ° C to 190 ° C or less.

  The residual solvent in the film is preferably 20 to 0%, more preferably 15 to 0%.

  Specifically, it is preferable that the residual solvent is stretched by 11% at 155 ° C., or the residual solvent is stretched by 2% at 155 ° C. Alternatively, the residual solvent is preferably stretched at 11% at 160 ° C., or the residual solvent is preferably stretched at less than 1% at 160 ° C.

  There is no particular limitation on the method of stretching the web. For example, a method in which a difference in peripheral speed is applied to a plurality of rolls, and the roll peripheral speed difference is used to stretch in the longitudinal direction between the rolls. And a method of stretching in the vertical direction, a method of stretching in the horizontal direction and stretching in the horizontal direction, a method of stretching in the vertical and horizontal directions and stretching in both the vertical and horizontal directions, and the like. Of course, these methods may be used in combination.

  In the case of the so-called tenter method, driving the clip portion by a linear drive method is preferable because smooth stretching can be performed and the risk of breakage and the like can be reduced.

  These width maintenance or lateral stretching in the film forming step is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

  The slow axis or the fast axis of the cellulose ester film according to the present invention is present in the film plane, and θ1 is preferably −1 ° or more and + 1 ° or less when the angle formed with the film forming direction is θ1. More preferably, it is 0.5 ° or more and + 0.5 ° or less.

  This θ1 can be defined as the orientation angle, and the measurement of θ1 can be performed using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments). Each of θ1 satisfying the above relationship can contribute to obtaining high luminance in a display image, suppressing or preventing light leakage, and contributing to obtaining faithful color reproduction in a color liquid crystal display device.

<Physical properties of cellulose ester film>
The moisture permeability of the cellulose ester film according to the present invention is preferably 300 to 1800 g / m ² · 24 h at 40 ° C. and 90% RH, more preferably 400 to 1500 g / m ² · 24 h, and 40 to 1300 g / m ² · 24 h. Is particularly preferred. The moisture permeability can be measured according to the method described in JIS Z 0208.

  The cellulose ester film according to the present invention preferably has a breaking elongation of 10 to 80%, more preferably 20 to 50%.

  The visible light transmittance of the cellulose ester film according to the present invention is preferably 90% or more, and more preferably 93% or more.

  The haze of the cellulose ester film according to the present invention is preferably less than 1%, particularly preferably 0 to 0.1%.

≪Acrylic active energy ray curable adhesive≫
The acrylic active energy ray curable adhesive (acrylic curable adhesive) according to the present invention has a SP value (solubility parameter) of 29.0 when the total amount of the composition is 100% by mass as a curable component. 20 to 60% by mass of the radically polymerizable compound (A) in the range of ˜32.0 (kJ / m ³ ) ^1/2 and an SP value of 18.0 (kJ / m ³ ) ^½ or more 21. 10 to 30% by mass of the radical polymerizable compound (B) within a range of less than 0 (kJ / m ³ ) ^1/2 and an SP value of 21.0 to 23.0 (kJ / m ³ ) ^1/2 It is preferable to contain 20-60 mass% of radically polymerizable compounds (C) which are in the range. In the present invention, the “composition total amount” means the total amount including various initiators and additives in addition to the radical polymerizable compound.

The radically polymerizable compound (A) is a compound having a radically polymerizable group such as a (meth) acrylate group and having an SP value in the range of 29.0 to 32.0 (kJ / m ³ ) ^1/2. If there is no limitation, it can be used. Specific examples of the radical polymerizable compound (A) include hydroxyethyl acrylamide (SP value 29.6), N-methylol acrylamide (SP value 31.5) and the like. In the present invention, the (meth) acrylate group means an acrylate group or a methacrylate group.

The radically polymerizable compound (B) has a radically polymerizable group such as a (meth) acrylate group and has an SP value of 18.0 (kJ / m ³ ) ^1/2 or more and 21.0 (kJ / m ³ ). ^Any compound that is within the range of less than ^1/2 can be used without limitation. Specific examples of the radically polymerizable compound (B) include, for example, tripropylene glycol diacrylate (SP value 19.0), 1,9-nonanediol diacrylate (SP value 19.2), and tricyclodecane dimethanol dimer. Acrylate (SP value 20.3), cyclic trimethylolpropane formal acrylate (SP value 19.1), dioxane glycol diacrylate (SP value 19.4), EO-modified diglycerin tetraacrylate (SP value 20.9), etc. Is mentioned. In addition, as a radically polymerizable compound (B), a commercial item can also be used conveniently, for example, Aronix M-220 (made by Toagosei Co., Ltd., SP value 19.0), light acrylate 1,9ND-A (Kyoeisha Chemical Co., Ltd.). Manufactured, SP value 19.2), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., SP value 20.9), light acrylate DCP-A (manufactured by Kyoeisha Chemical Co., SP value 20.3), SR-531 (Sartomer) And SP-value 19.1), CD-536 (Sartomer, SP value 19.4), and the like.

The radically polymerizable compound (C) has a radically polymerizable group such as a (meth) acrylate group and has an SP value in the range of 21.0 to 23.0 (kJ / m ³ ) ^1/2 If it is, it can be used without limitation. Specific examples of the radical polymerizable compound (C) include, for example, acryloylmorpholine (SP value 22.9), N-methoxymethylacrylamide (SP value 22.9), N-ethoxymethylacrylamide (SP value 22.3). Etc. In addition, as a radically polymerizable compound (C), a commercial item can also be used suitably, for example, ACMO (the Kojin company make, SP value 22.9), Wasmer 2MA (the Kasano Kosan company make, SP value 22.9). , Wasmer EMA (manufactured by Kasano Kosan Co., Ltd., SP value 22.3), Wasmer 3MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.4), and the like.

  When the glass transition temperature (Tg) of each of the radically polymerizable compounds (A), (B) and (C) is 60 ° C. or higher, the Tg of the adhesive layer is increased and the durability is particularly excellent. It will be. As a result, for example, when an adhesive layer of a polarizer and a retardation film is used, occurrence of heat shock cracks in the polarizer can be prevented. Here, the Tg of the homopolymer of the radical polymerizable compound means Tg when the radical polymerizable compound is cured (polymerized) alone.

The acrylic curable adhesive composition according to the present invention contains radically polymerizable compounds (A), (B) and (C) in a total of 85 to 100 parts by mass, and further has an SP value of 23.0 (kJ / m ^{3) 1/2} exceeds 29.0 ^(kJ / ^{m 3)} radically polymerizable compound is less than ^1/2 the (D) may contain 0 to 15 parts by weight. Specific examples of the radical polymerizable compound (D) include, for example, 4-hydroxybutyl acrylate (SP value 23.8), 2-hydroxyethyl acrylate (SP value 25.5), N-vinylcaprolactam (trade name V- CAP, manufactured by ISP, SP value 23.4), 2-hydroxypropyl acrylate (SP value 24.5), and the like.

  When the acrylic curable adhesive composition according to the present invention is used in an electron beam curable type, it is not particularly necessary to include a photopolymerization initiator in the composition. It is preferable to use a polymerization initiator, and it is particularly preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more. A photopolymerization initiator having high sensitivity to light of 380 nm or more will be described later.

  In the acrylic curable adhesive composition according to the present invention, a compound having a structure represented by the following general formula (6) is used alone as a photopolymerization initiator, or is represented by the general formula (6). It is preferable to use a compound having a structure having a photopolymerization initiator, which is described later, and a photopolymerization initiator highly sensitive to light of 380 nm or more.

In General Formula (6), R ₁ and R ₂ represent a hydrogen atom, an ethyl group, an isopropyl group, or a chlorine atom, and R ₁ and R ₂ may be the same or different. When the compound having the structure represented by the general formula (6) is used, the adhesiveness is excellent as compared with a case where a photopolymerization initiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds having the structure represented by the general formula (6), diethylthioxanthone in which R ₁ and R ₂ are —CH ₂ CH ₃ is particularly preferable. The composition ratio of the compound having the structure represented by the general formula (6) in the composition is preferably 0.1 to 5.0% by mass when the total amount of the composition is 100% by mass. It is more preferable that it is 5-4.0 mass%, and it is still more preferable that it is 0.9-3.0 mass%.

  Moreover, it is preferable to add a polymerization initiation assistant as required. Examples of polymerization initiators include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and the like. Among them, ethyl 4-dimethylaminobenzoate is particularly preferable. When using the polymerization initiation assistant, the amount added is usually 0 to 5% by mass, preferably 0 to 4% by mass, most preferably 0 to 3% by mass when the total amount of the composition is 100% by mass. .

  Moreover, a well-known photoinitiator can be used together as needed. Since the transparent retardation film having UV absorption ability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more as the photopolymerization initiator. Specifically, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2 -(Dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -Phenyl) titanium and the like.

  In particular, it is preferable to use a compound having a structure represented by the following general formula (7) as the photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (6).

In general formula (7), R ₁ , R ₂ and R ₃ represent a hydrogen atom, a methyl group, an ethyl group, an isopropyl group or a chlorine atom, and R ₁ , R ₂ and R ₃ may be the same or different. As a compound having the structure represented by the general formula (2), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: Irgacure907) manufacturer: BASF Japan Can be suitably used. In addition, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name: Irgacure 369 manufacturer: manufactured by BASF Japan Ltd.), 2- (dimethylamino) -2-[(4-methyl Phenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (trade name: Irgacure 379 manufacturer: manufactured by BASF Japan) is preferable because of its high sensitivity.

《Polarizer》
A polarizer, which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass. A typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed.

  For the polarizer, a polyvinyl alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then preferably subjected to a durability treatment with a boron compound. The film thickness of the polarizer is preferably 5 to 30 μm, particularly preferably 10 to 20 μm.

  Further, the ethylene unit content described in JP-A-2003-248123, JP-A-2003-342322, etc. is 1 to 4 mol%, the degree of polymerization is 2000 to 4000, and the degree of saponification is 99.0 to 99.99 mol%. The ethylene-modified polyvinyl alcohol is also preferably used.

  Among them, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 ° C. is preferably used.

  The difference in hot water cutting temperature between two points 5 cm apart in the TD direction (width direction) of the film is more preferably 1 ° C. or less in order to reduce color unevenness, and further 1 cm in the TD direction of the film. In order to reduce color unevenness, it is more preferable that the difference in hot water cutting temperature between two distant points is 0.5 ° C. or less.

  A polarizer using this ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability, and has little color unevenness, and is particularly preferably used for a large-sized liquid crystal display device.

  In the present invention, the polarizer obtained as described above has a retardation film according to the present invention bonded to one surface and a protective film bonded to the other surface as a polarizing plate. used. As the adhesive used for pasting, the above-mentioned acrylic curable adhesive is used, and even if it is a thin film coating of less than 1.0 μm, strong adhesiveness can be obtained.

"Protective film"
As a protective film used for the polarizing plate of this invention, what is generally used as a protective film of a polarizing plate can be used.

  For example, commercially available cellulose ester films (for example, Konica Minoltack KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC8UX-RHA, KC8UX-RHA, KC8UX KC4UXW-RHA-NC, manufactured by Konica Minolta, Inc.) is preferably used.

  The polarizing plate protective film used on the surface side (viewing side) of the liquid crystal display device may have an antireflection layer, an antistatic layer, an antifouling layer, and a backcoat layer in addition to the antiglare layer or the clear hard coat layer. preferable.

<Method for producing polarizing plate>
The polarizing plate comprises an adhesive application step of forming the adhesive layer by applying the acrylic curable adhesive described above to at least one of the adhesive surfaces of the polarizer and the retardation film, and the adhesive layer. A bonding step of bonding the polarizer and the retardation film through the adhesive layer, and a curing step of curing the adhesive layer in a state where the polarizer and the retardation film are bonded through the adhesive layer. It can manufacture with the manufacturing method containing. Moreover, there may be a pretreatment step in which the surface of the retardation film to which the polarizer is adhered is subjected to an easy adhesion treatment.

(Pretreatment process)
In the pretreatment step, the surface of the retardation film that adheres to the polarizer is subjected to easy adhesion treatment. When the retardation film and the protective film are bonded to both surfaces of the polarizer, easy adhesion treatment is performed on each of the retardation film and the protective film. In the next adhesive application process, the surface subjected to the easy adhesion treatment is treated as a bonding surface with the polarizer, and therefore, on both surfaces of the retardation film, the surface to be bonded with the acrylic curable adhesive is easy. Apply adhesive treatment. Examples of the easy adhesion treatment include corona treatment and plasma treatment.

(Adhesive application process)
In the adhesive application step, the acrylic curable adhesive is applied to at least one of the adhesive surfaces of the polarizer and the retardation film. When the acrylic curable adhesive is applied directly to the surface of the polarizer or the retardation film, the application method is not particularly limited. For example, various wet coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. In addition, a method in which an acrylic curable adhesive is cast between a polarizer and a retardation film, and then pressurized with a roller or the like to uniformly spread the adhesive can be used.

(Bonding process)
After apply | coating an acrylic curable adhesive by said method, it processes by a bonding process. In this bonding step, for example, when an acrylic curable adhesive is applied to the surface of the polarizer in the previous application step, a retardation film is superimposed thereon. When an acrylic curable adhesive is applied to the surface of the retardation film in the previous application step, a polarizer is superimposed thereon. When an acrylic curable adhesive is cast between the polarizer and the retardation film, the polarizer and the retardation film are superposed in that state.

  When a retardation film and a protective film are adhered to both sides of a polarizer, and both sides use an acrylic curable adhesive, both sides of the polarizer are each subjected to retardation via an acrylic curable adhesive. A film and a protective film are overlaid. Usually, both sides in this state (when the retardation film is overlaid on one side of the polarizer, when the retardation film and the protective film are overlaid on the polarizer side and the retardation film side, and on both sides of the polarizer) Is sandwiched by rollers or the like from both sides of the retardation film and the protective film side) and pressed. As the material of the roller, metal, rubber or the like can be used. The rollers arranged on both sides may be made of the same material or different materials.

(Curing process)
In the curing step, an active energy ray is irradiated to an uncured acrylic curable adhesive, and a cationic polymerizable compound (for example, epoxy compound or oxetane compound) or a radical polymerizable compound (for example, acrylate compound or acrylamide compound). Etc.) is cured, and the polarizer and the retardation film, or the polarizer and the retardation film, which are superposed via the acrylic curable adhesive, are adhered. When laminating a retardation film on one side of a polarizer, the active energy ray may be irradiated from either the polarizer side or the retardation film side. In addition, when laminating a retardation film and a protective film on both sides of a polarizer, active energy rays in a state where the retardation film and the protective film are superimposed on both sides of the polarizer via an acrylic curable adhesive, respectively. It is advantageous to simultaneously cure the acrylic curable adhesive on both sides.

  Visible light, ultraviolet rays, X-rays, electron beams, etc. can be used as the active energy rays applied for curing, but electron beams and ultraviolet rays are generally preferred because they are easy to handle and have a sufficient curing rate. Used.

  Any appropriate condition can be adopted as the electron beam irradiation condition as long as the adhesive can be cured. For example, in the electron beam irradiation, the acceleration voltage is preferably in the range of 5 to 300 kV, more preferably in the range of 10 to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive and may be insufficiently cured. If the acceleration voltage exceeds 300 kV, the penetrating force through the sample is too strong and the electron beam rebounds. There is a risk of damaging the polarizer. The irradiation dose is in the range of 5 to 100 kGy, more preferably in the range of 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive becomes insufficiently cured, and when it exceeds 100 kGy, the retardation film and the polarizer are damaged, resulting in a decrease in mechanical strength and yellowing to obtain predetermined optical characteristics. I can't.

Arbitrary appropriate conditions can be employ | adopted for the irradiation conditions of an ultraviolet-ray, if it is the conditions which can cure | harden the said adhesive agent. The dose of ultraviolet rays is preferably in the range of 50~1500mJ / cm ² in accumulated light quantity, and even more preferably in the range of 100 to 500 mJ / cm ^2.

  When the production method is performed in a continuous line, the line speed depends on the curing time of the adhesive, but is preferably in the range of 1 to 500 m / min, more preferably 5 to 300 m / min, and still more preferably 10 to 100 m. / Min. If the line speed is too slow, the productivity is poor, or the retardation film is damaged too much, and a polarizing plate that can withstand a durability test cannot be produced. When the line speed is too high, the adhesive is not sufficiently cured, and the desired adhesiveness may not be obtained.

  In the polarizing plate obtained as described above, the thickness of the adhesive layer is not particularly limited, but in the present invention, sufficient adhesiveness can be obtained even with a coating amount of less than 1.0 μm.

≪Liquid crystal display device≫
The polarizing plate of the present invention is used for a VA liquid crystal display device.

  FIG. 1 is a schematic diagram showing an example of the configuration of a VA liquid crystal display device 108 using the polarizing plate of the present invention. In the form shown in FIG. 1, 101A and 101B are polarizing plates of the present invention, which are arranged on both sides with the liquid crystal cell 107 in between. 101B is arranged on the VA liquid crystal display backlight (BL) side, and 101A is arranged on the viewing side. The polarizing plates 101A and 101B have the same configuration, and from the liquid crystal cell side, from the retardation film 105, the acrylic curable adhesive 103B, the polarizer 104, the acrylic curable adhesive 103A, and the protective film 102 according to the present invention. It is configured.

  The retardation film 105 and the polarizer 104 are bonded via an acrylic curable adhesive 103B. As the protective film 102, for example, a KC6UA film (manufactured by Konica Minolta Co., Ltd.) or the like is used.

  The retardation film according to the present invention can be used for liquid crystal display devices of various drive systems such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS, OCB.

  A VA (MVA, PVA) type liquid crystal display device is preferable.

  In particular, even for a large-screen liquid crystal display device with a screen size of 30 or more, it is possible to obtain a liquid crystal display device that is less affected by environmental fluctuations, has reduced light leakage, and has excellent visibility such as color unevenness and front contrast. it can.

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

  The cellulose ester derivatives used in the examples are shown in Table 1.

Example 1
<Production of Cellulose Ester Film 101>
<Fine particle dispersion 1>
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by mass Ethanol 89 parts by mass The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin to prepare a fine particle dispersion 1.

<Fine particle addition liquid 1>
The fine particle dispersion 1 prepared as described above was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

Composition of fine particle addition liquid 1 Methylene chloride 99 parts by mass Fine particle dispersion 1 5 parts by mass A main dope having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose ester C2 and polyhydric alcohol ester E-1 were added to a pressure dissolution tank containing a solvent while stirring. While this was heated and stirred, it was completely dissolved, and this was dissolved in Azumi Filter Paper No. The main dope was prepared by filtration using 244.

In addition, the cellulose ester which concerns on this invention melt | dissolves 100 mass parts in 800 mass parts acetone, and Toyo Filter Paper Co., Ltd. product No. Each of the six sheets was filtered at a gauge pressure of 0.2 MPa / cm ² , then dry-spun, and a single yarn fineness of 3 denier and a total fineness of 36,000 denier were used.

<Composition of main dope>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose ester C2 100 parts by mass Polyhydric alcohol ester E-1 15 parts by mass Particulate additive solution 1 1 part by mass did. Then, using an endless belt casting apparatus, the main dope was cast uniformly on a stainless steel belt support at a temperature of 33 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

  On the stainless steel belt support, the solvent was evaporated until the amount of residual solvent in the cast (cast) film was 75% by mass, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.

  The peeled cellulose ester film was stretched 35% in the width direction using a tenter while applying heat at 150 ° C. The residual solvent at the start of stretching was 15% by mass.

  Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m.

  As described above, a cellulose ester film 101 having a dry film thickness of 40 μm was obtained.

<Preparation of cellulose ester film 102>
In producing the cellulose ester film 101, a cellulose ester film 102 was produced in the same manner except that the composition of the main dope was as follows.

<Composition of main dope>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose ester C3 100 parts by mass Polyhydric alcohol ester E-1 15 parts by mass Particulate additive liquid 1 1 part by mass

<Preparation of cellulose ester films 103-143>
Cellulose ester derivatives in the same manner except that the types and addition amounts of cellulose ester derivatives, polyhydric alcohol esters, 5-membered or 6-membered heterocyclic groups and sugar esters in the main dope are as shown in Table 2 and Table 3. Films 103 to 143 were produced.

<Preparation of cellulose ester film 144>
In the production of the cellulose ester film 101, a cellulose ester film 144 was produced in the same manner except that the polyhydric alcohol ester was replaced with the polyester compound P14 and the composition of the main dope was as follows.

<Composition of main dope>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose ester C1 100 parts by mass Polyester compound P14 4 parts by mass Compound H-92 having a heterocyclic group 4 parts by mass Sugar ester a3 10 parts by mass Particulate additive liquid 1 1 part by mass

上記のようにして作製したセルロースエステルフィルム１０１〜１３７は本発明に係る位相差フィルムであり、セルロースエステルフィルム１３８〜１４４は比較例の位相差フィルムである。

The cellulose ester films 101 to 137 produced as described above are retardation films according to the present invention, and the cellulose ester films 138 to 144 are retardation films of comparative examples.

<Evaluation method>
<< Measurement of phase difference values Ro and Rt >>
A 35 mm × 35 mm sample was cut out from the film obtained above, conditioned at 23 ° C. and 55% RH for 2 hours, and measured from the vertical direction at 590 nm with an automatic birefringence meter “KOBRA21ADH” (manufactured by Oji Scientific Instruments). And the extrapolated value of the retardation value measured in the same manner while tilting the film surface.

<Measurement method of penetration depth into film>
100 parts by mass of 4HBA acrylic monomer and 3 parts by mass of Irgacure 819 (manufactured by BASF Japan) were mixed and stirred at 50 ° C. for 1 hour to obtain an acrylic curable adhesive that was a test liquid for penetration depth measurement. . Thereafter, the test solution was heated to 50 ° C., and uniformly applied to an optical film with a thickness of 2.0 μm. After 30 seconds from the application, Fusion UV Systems, Inc. Light HAMMER 10 (gallium) was used as an irradiation device. Using an enclosed metal halide lamp, the adhesive layer was cured by irradiating with ultraviolet rays under the following conditions. The irradiation conditions were as follows: bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated irradiation amount (integrated light amount): 1000 mJ / cm ² (wavelength 380 to 440 nm).

  The penetration depth of the test solution was observed by cross-sectional observation measurement of the obtained laminated film with TEM (Transmission Electron Microscopy) “JEM-2010F” (manufactured by JEOL Ltd.). The results are shown in Table 4.

<< Example 2 >>
<Preparation of polarizing plate>
A polyvinyl alcohol film having a thickness of 120 μm 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 polarizer.

(Adjustment of acrylic curable adhesive composition)
As radically polymerizable compounds, HEAA (hydroxyethylacrylamide) Kojin Co., Ltd., Aronix M-220 (Tripropylene glycol diacrylate) Toagosei Co., Ltd., ACMO (acryloylmorpholine) Kojin Co., Ltd. 53.5% by mass, 14.6% by mass, 29.2% by mass, KAYACURE DETX-S (diethylthioxanthone) manufactured by Nippon Kayaku Co., Ltd. as photopolymerization initiator, Irgacure907 (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane -1-one) 1.35% by mass of BASF Japan, respectively, were mixed and stirred at 50 ° C. for 1 hour to obtain an acrylic curable adhesive composition.

(Active energy rays)
As the active energy rays, ultraviolet rays (gallium sealed metal halide lamp) irradiation apparatus: Fusion UV Systems, Inc, Inc. Light HAMMER10 Valve: V Valve peak irradiance: 1600 mW / cm ^2, integrated dose (integrated light quantity) 1000 mJ / cm ² (wavelength 380 ~ 440nm) was used. In addition, the illumination intensity of the ultraviolet-ray was measured using the Sola-Check system by Solatell.

  Subsequently, a polarizer, the cellulose ester films 101 to 144, and Konica Minolta Tack KC4UY (Konica Minolta Co., Ltd. cellulose ester film) were bonded to each other according to the following steps 1 and 2 to prepare a polarizing plate.

  Step 1: On the cellulose ester films 101 to 144 and the Konica Minolta Tack KC4UY, the acrylic curable adhesive composition prepared in advance is applied to an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roll). The number of lines was 1000 / inch, the rotation speed was 140% / line speed), and the film was applied to a thickness of 0.5 μm and bonded to both sides of the polarizer by a roll machine.

  Step 2: Thereafter, the film (both sides) is heated to 50 ° C. using an IR heater, and the ultraviolet ray is irradiated on both sides to cure the acrylic curable adhesive composition, and then at 70 ° C. for 3 minutes. It dried with hot air and obtained the polarizing plates 201-244. The line speed of bonding was 25 m / min.

  The adhesive strength (vs. cellulose ester film) and durability (heat shock test) of each obtained polarizing plate were evaluated based on the following conditions.

<Adhesive strength>
The obtained polarizing plates 201 to 244 were each cut into a size of 15 mm × 150 mm to obtain samples. The sample was affixed on the glass plate with the double-sided adhesive tape (Nitto Denko Co., Ltd. product, No. 500). The sample (polarizing plate) was previously provided with a peeling trigger between the retardation film and the polarizer, and the peeling trigger was chucked to a variable angle peel tester (Asahi Seiko Co., Ltd.) to peel strength ( N / 15 mm). The measurement conditions were normal temperature (23 ° C.), peel angle: 90 degrees, and peel speed: 3000 mm / min. Data obtained between 50 and 100 mm of the obtained measurement data was averaged.

《Durability (heat shock test)》
The pressure-sensitive adhesive layer was laminated on the cellulose ester film surface of the polarizing plate 201 to 244 according to the present invention, and cut into a rectangle of 200 mm in the stretching direction of the polarizer and 400 mm in the vertical direction. The polarizing plate was laminated on a glass plate, a heat shock test at −40 to 85 ° C. was performed, the polarizing plate after 50 cycles was visually observed, and evaluated based on the following criteria. In the heat shock test, the holding time at −40 ° C. and 85 ° C. was 30 minutes, and the heating rate and the cooling rate were 5 ° C./min.

(Criteria)
○: No occurrence of cracks Δ: Cracks that do not penetrate in the stretching direction of the polarizer occurred (crack length 200 mm or less)
×: Cracks penetrating in the stretching direction of the polarizer occurred (crack length 200 mm)
The evaluation results are shown in Table 4.

From the above results, it can be seen that the retardation films 101 to 137 according to the present invention are suppressed in the permeability of 4HBA and are excellent in adhesion and durability when used as a polarizing plate. Moreover, the polarizing plates 201-237 of the present invention using the retardation films 101-137 were excellent in adhesive strength and durability.
The retardation films 101 to 137 according to the present invention have an in-plane retardation value Ro in the range of 40 nm ≦ | Ro | ≦ 100 nm, and a retardation value Rt in the film thickness direction of 100 nm. ≦ | Rt | ≦ 300 nm, which is the range of the retardation value of the retardation film for VA, and it can be seen that the present invention is effective in the range of the retardation value of the retardation film for VA.

Example 3
<Production of liquid crystal display device>
Using a commercially available VA-type liquid crystal display device (SONY 40-type display KLV-40J3000), the polarizing plates bonded to both surfaces of the liquid crystal cell were peeled off, and the above-prepared polarizing plates 203, 208, 213, 218, 230 were used. , 240, 241, and 242 were bonded to both surfaces of the liquid crystal cell as shown in FIG. 1 to prepare VA liquid crystal display devices 301 to 308. At that time, the direction of the absorption axis of the polarizing plate was adjusted to the same direction as the polarizing plate bonded in advance.

<Evaluation of liquid crystal display device>
The liquid crystal display devices prepared above were evaluated as follows, and the results are shown in Table 5.

(Evaluation of moisture resistance: Evaluation of uneven color due to water content fluctuation)
Bencot (manufactured by Asahi Kasei Fibers Co., Ltd.) soaked in water was placed on the surface of the liquid crystal display device produced above and held for 30 hours in a state where moisture did not evaporate. Next, each liquid crystal display device was turned on, the uniformity of the display screen was visually evaluated, and the moisture resistance was evaluated according to the following criteria.

(Criteria)
A: No color unevenness is observed at all B: Weak color unevenness is observed, but the quality has no problem in practical use C: Strong color unevenness is generated and the moisture resistance is problematic

  It can be seen that the VA type liquid crystal display devices 301 to 305 of the present invention are excellent in that no color unevenness occurs even in a strong and high humidity environment where water directly adheres.

  The polarizing plate of the present invention can be used for a VA liquid crystal display device, and is used for a display, particularly a display of an information terminal device such as a large television, a personal computer, a tablet personal computer and a smartphone, and a monitor of a digital camera. be able to.

101A, 101B Polarizing plate 102 Protective film 103A, 103B Acrylic active energy ray-curable adhesive 104 Polarizer 105 Retardation film 107 Liquid crystal cell 108 Liquid crystal display device BL Back light

Claims (11)

The retardation film and the protective film are each a polarizing plate bonded opposite to one of the surfaces of the polarizer,
The polarizer and the retardation film are bonded with an acrylic active energy ray-curable adhesive,
The retardation film includes at least a cellulose ester,
A compound that suppresses the permeability of the acrylic active energy ray-curable adhesive;
A retardation film produced from a resin composition containing
The acyl group substitution degree of the cellulose ester satisfies the following formula (I),
And the penetration depth of the test solution when 4-hydroxydibutyl acrylate is used as a test solution for evaluating the permeability of the acrylic active energy ray-curable adhesive into the retardation film,
A polarizing plate characterized by being within a range of 0.1 to 1.0 μm at 50 ° C. for 30 seconds.
Formula (I): 2.0 ≦ X + Y ≦ 2.6
(However, in formula (I), X represents an acetyl group substitution degree and Y represents a propionyl group substitution degree or a butyryl group substitution degree.)   The retardation film has an in-plane retardation value Ro in a range of 40 nm ≦ | Ro | ≦ 100 nm in a measurement wavelength of 590 nm, 23 ° C. and 55% RH, and a film thickness direction level. The phase difference value Rt is in the range of 100 nm ≦ | Rt | ≦ 300 nm. The compound which suppresses the permeability of the acrylic active energy ray-curable adhesive is a polyhydric alcohol ester having a structure represented by the following general formula (1). The polarizing plate as described in.
General formula (1)
B ₁ -G ₁ -B ₂
(However, in General Formula (1), B ₁ and B ₂ each independently represents an aliphatic monocarboxylic acid residue or an aromatic monocarboxylic acid residue. G ₁ has 2 to 12 carbon atoms. Represents an alkylene glycol residue having a straight-chain or branched structure. B ₁ and B ₂ in the polyhydric alcohol ester having the structure represented by the general formula (1) are both aliphatic monocarboxylic acid residues having 1 to 10 carbon atoms. The polarizing plate according to claim 3.   5. The polarizing plate according to claim 3, wherein a content of the polyhydric alcohol ester is in a range of 1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester.   The polarizing plate according to claim 1, wherein the resin composition contains a compound having a 5-membered or 6-membered aromatic heterocyclic group. The polarizing plate according to claim 6, wherein the compound having a 5-membered or 6-membered aromatic heterocyclic group is a compound having a structure represented by the following general formula (2).

(In the general formula (2), A ₁ and A ₂ each independently represents an alkyl group, a cycloalkyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group. B is an aromatic hydrocarbon. T ₁ and T ₂ each independently represent a 1,2,4-triazole ring, L ₁ , L ₂ , L ₃ and L ₄ each independently represent a single bond Alternatively, it represents a divalent linking group, and n represents an integer of 0 to 5.)   The content of the compound having the 5-membered or 6-membered aromatic heterocyclic group is in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester. Item 8. The polarizing plate according to Item 7.   The polarizing plate according to claim 1, wherein the resin composition contains a sugar ester.   The polarizing plate according to claim 9, wherein a content of the sugar ester is in a range of 1 to 20 parts by mass with respect to 100 parts by mass of the cellulose ester.   A VA liquid crystal display device using the polarizing plate according to any one of claims 1 to 10.

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