JP6465025B2 - Polarizing plate and liquid crystal display device having the same - Google Patents

Description

  The present invention relates to a polarizing plate and a liquid crystal display device including the polarizing plate. More specifically, the present invention relates to a polarizing plate in which generation of color unevenness and point defects is suppressed, and a liquid crystal display device including the polarizing plate.

  The demand for liquid crystal display devices is expanding in applications such as liquid crystal televisions and personal computer liquid crystal displays. A liquid crystal display device is generally composed of a liquid crystal cell in which a transparent electrode, a liquid crystal layer, a color filter and the like are sandwiched between glass plates, and two polarizing plates provided on both sides thereof. Each polarizing plate is usually configured by sandwiching a polarizer between two transparent resin films.

  Conventionally, a liquid crystal display device has a major drawback that the viewing angle dependency of a display image is large. However, a wide viewing angle liquid crystal mode such as a VA mode has been put into practical use, and thereby, a high-quality image such as a television can be obtained. In demanded markets, the demand for liquid crystal display devices is expanding rapidly.

  In the VA (Vertical Alignment) mode, when the liquid crystal cell is not driven, the liquid crystal molecules of the liquid crystal cell are aligned perpendicular to the substrate, so that the light does not change in polarization and the liquid crystal layer Pass through. For this reason, by arranging the linearly polarizing plates so that the absorption axes are orthogonal to each other above and below the liquid crystal panel, almost complete black display can be obtained when viewed from the front, and a high contrast ratio can be obtained. .

  In the VA mode liquid crystal display device, two polarizing plates are provided on both sides of the liquid crystal cell, and the inner (liquid crystal cell side) resin film is a film having an optical compensation function, and the outer resin film on the side far from the liquid crystal cell. Is generally used as a protective film. A cellulose acylate film is conventionally known as such a resin film.

  In recent years, as the use of liquid crystal display devices has been expanded, large-size and high-quality applications such as televisions have been expanded, and higher quality is required for polarizing plates. In particular, as the liquid crystal display device becomes thinner, the polarizing plate is required to be thinner.

  However, if the cellulose acylate film is thinned for this purpose, there arises a problem that mechanical strength is lowered and moisture permeability becomes high as a protective film. When the moisture permeability of the protective film is increased, the optical compensation film has a problem that the phase difference value largely fluctuates with respect to environmental humidity fluctuations.

  For such problems, it is known to use a resin with low moisture permeability as a protective film. For example, Patent Document 1 proposes a technique using polyethylene terephthalate (PET) as a protective film for a polarizing plate. Patent Document 2 proposes a technique using a norbornene resin as a retardation film.

  However, if a protective film with low moisture permeability is used for both the outer resin film and the inner resin film of the polarizing plate, moisture tends to stay inside the polarizing plate. Problems such as defects are likely to occur.

  With respect to this problem, in Patent Document 3, the resin film outside the polarizing plate is made of acrylic resin, and the resin film inside the polarizing plate (liquid crystal cell side) is made of a cellulose-based resin film, so that moisture in the external environment is moderately adjusted. A technique is disclosed that absorbs or discharges, prevents moisture from accumulating inside the polarizing plate, and suppresses defects caused by moisture.

  However, in such a configuration, moisture is absorbed or discharged from the inner resin film more than the outer resin film, resulting in phase difference fluctuations with respect to environmental humidity fluctuations, resulting in the color of the display device. A defect such as unevenness occurred, and it was not sufficient as a countermeasure for the above-mentioned problem against environmental humidity fluctuations.

Japanese Patent No. 4926661 JP-A-8-43812 JP 2012-181277 A

  The present invention has been made in view of the above problems and situations, and a problem to be solved is to provide a polarizing plate in which the occurrence of color unevenness and point-like defects is suppressed. Moreover, it is providing the liquid crystal display device provided with it.

  As a result of studying the cause of the above-mentioned problems in order to solve the above problems, the present inventor used a protective film having low moisture permeability on the outside of the polarizing plate, and cellulose resin on the inner side (liquid crystal cell side) of the polarizing plate. It has been found that the above-mentioned problems can be solved by using a compound having a specific structure having a biphenyl skeleton and an ether structure, an ester structure or an amide structure together with an acylate resin.

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

1. An optical film A, a polarizer and an optical film B are polarizing plates laminated in this order, and the optical film A is an optical film containing at least one of an acrylic resin or a polyester resin, and the optical film B is a cellulose acylate resin having an acyl group substitution degree in the range of 2.1 to 2.70, and any of compounds having structures represented by the following formulas (1-1) to (1-3) A polarizing plate comprising a retardation film containing

(Wherein R ^{1 to} R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ⁵ and R ⁶ each independently represents an alkyl group having a substituent or a substituent. .L ¹ represents an aromatic hydrocarbon ring which may have a group. the substituent is at least one epoxy group, hydroxy group, an alkoxy group, selected from the group consisting of acyloxy group and an aromatic group, L ² represents O, C (═O) O or C (═O) NR, wherein R represents a hydrogen atom or an alkyl group.)
2. The retardation value Ro in the in-plane direction and the retardation value Rt in the thickness direction of the optical film B are within the following ranges, respectively, in an environment of 23 ° C. and 55% RH. The polarizing plate as described in a term.

Ro: 20 to 130 nm
Rt: 100 to 300 nm
3. The film thickness of the said optical film B exists in the range of 10-90 micrometers, The polarizing plate of 1st term | claim or 2nd term | claim characterized by the above-mentioned.

4). Any one of Items 1 to 3, wherein the cellulose acylate resin contained in the optical film B is a cellulose acetate resin having an acetyl group substitution degree in the range of 2.1 to 2.70 . The polarizing plate according to one item.

5. Any one of Items 1 to 4, wherein the cellulose acylate resin contained in the optical film B is a cellulose acetate resin having an acetyl group substitution degree in the range of 2.6 to 2.70 . The polarizing plate according to one item.

6). The optical film B is, the polarizing plate according to any one of claims 1 to 5, characterized that you containing a compound having a structure represented by the formula (1-2).

7 . The water vapor transmission rate at 40 ° C. and 90% RH of the optical film A is in the range of ^{20 to} 120 g / m ² · 24 hr, wherein the optical film A is any one of items 1 to 6. Polarizing plate.

8). The polarizing plate according to any one of Items 1 to 7, wherein the optical film B has a thickness in the range of 10 to 40 μm.

  9. The said optical film B contains the nitrogen-containing phase difference increasing agent, The polarizing plate as described in any one of 1st term | claim to 8th term | claim characterized by the above-mentioned.

（式中、Ａ _１ 、Ａ _２ 及びＢ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、ピロール環、ピラゾール環、イミダゾール環、１，２，３−トリアゾール環又は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個以下の原子を介して連結する２価の連結基を表す。ｎは０〜５の整数を表す。） 10. The nitrogen-containing retardation increasing agent is at least one selected from compounds having a carbazole ring, a quinoxaline ring, a benzoxazole ring, an oxadiazole ring, an oxazole ring, a triazole ring, and a pyrazole ring. Item 10. The polarizing plate according to item 9.
11. Item 10. The polarizing plate according to item 9, wherein the nitrogen-containing retardation increasing agent is a compound having a structure represented by the following general formula (3).

(In the formula, A ₁ , A ₂ and B each independently represent an alkyl group, a cycloalkyl group, an aromatic hydrocarbon ring or an aromatic heterocyclic ring. T ₁ and T ₂ are each independently a pyrrole ring. , Pyrazole ring, imidazole ring, 1,2,3-triazole ring or 1,2,4-triazole ring, L ₁ , L ₂ , L ₃ and L ₄ are each independently a single bond or 2 or less. Represents a divalent linking group linked via an atom of n. N represents an integer of 0 to 5.)

12 . Wherein the optical film A and the optical film B is, any one of that being stuck to the polarizer by using an active energy ray-curable adhesive from each of the first term, wherein to paragraph 11 Polarizing plate described in

13 . A liquid crystal display device comprising the polarizing plate according to any one of items 1 to 12 .

  By the above means of the present invention, it is possible to provide a polarizing plate in which the occurrence of color unevenness and point defects is suppressed. In addition, a liquid crystal display device including the same can be provided.

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

  As an inner resin film (retardation film), a compound having a specific structure having a biphenyl skeleton and an ether structure, an ester structure or an amide structure (a compound having a structure represented by the general formula (1)) coexists with a cellulose acylate resin. It is considered that the ether structure, ester structure or amide structure portion of this compound has an interaction with the side chain or hydrogen atom of the cellulose acylate resin, and the interaction between the cellulose acylate resin and water is weakened. . In addition, the hydrophobic structure of the biphenyl skeleton is considered to further weaken the interaction between the cellulose acylate resin and water and suppress the occurrence of phase difference fluctuations due to fluctuations in environmental humidity. As a result, it is estimated that the occurrence of color unevenness in the display device could be suppressed. Therefore, as in the present invention, the outer resin film (protective film) is a film with low moisture permeability, and the inner resin film (retardation film) is a film with high moisture permeability such as cellulose acylate resin. However, it is considered that color unevenness did not occur, and in addition, the occurrence of point defects could be suppressed. In addition, lowering the moisture permeability of the outer resin film (protective film) can also reduce the influence of moisture from the outside, and has the effect of suppressing the occurrence of color unevenness. Therefore, in the present invention, it is considered that both of the color unevenness and the point-like defect of the display device that have been difficult to achieve both of the conventional methods can be solved.

Schematic diagram showing an example of the configuration of a liquid crystal display device Schematic diagram showing an example of a co-casting die

The polarizing plate of the present invention is a polarizing plate in which an optical film A, a polarizer, and an optical film B are laminated in this order, and the optical film A contains at least one of an acrylic resin or a polyester resin. The optical film B is a cellulose acylate resin having an acyl group substitution degree of 2.1 to 2.70 and a structure represented by the following formulas (1-1) to (1-3). It is a retardation film containing any of the compounds having the above . This feature is technical feature common to the invention according to each claim.

  As an embodiment of the present invention, the retardation value Ro in the in-plane direction and the retardation value Rt in the thickness direction of the optical film B are each in the environment of 23 ° C. and 55% RH, and Ro is 20 to 130 nm, respectively. Within the range, Rt is preferably within the range of 100 to 300 nm.

  Moreover, it is preferable that the film thickness of the optical film B exists in the range of 10-90 micrometers. More preferably, it is in the range of 10 to 40 μm.

  Furthermore, in this invention, it is preferable that the cellulose acylate resin contained in the optical film B is a cellulose acetate resin having an acetyl group substitution degree in the range of 2.1 to 2.7. Furthermore, it is preferable that it is a cellulose acetate resin in the range whose acetyl group substitution degree is 2.6-2.7.

  The compound having a structure represented by the general formula (1) is preferably a compound having a structure represented by the general formula (2).

Moreover, it is preferable that the water vapor permeability | transmittance in 40 degreeC * 90% RH of the optical film A exists in the range of 20-120 g / m < ² > * 24hr.

Furthermore, the optical film B preferably contains a nitrogen-containing retardation increasing agent, and the nitrogen-containing retardation increasing agent is a carbazole ring, quinoxaline ring, benzoxazole ring, oxadiazole ring, oxazole ring, triazole ring. And at least one selected from compounds having a pyrazole ring.
Moreover, it is preferable that the said nitrogen-containing phase difference increasing agent is a compound which has a structure represented by the said General formula (3).

  Moreover, it is preferable that the optical film A and the said optical film B are each bonded with the said polarizer using an active energy ray hardening adhesive.

  The polarizing plate of the present invention can be suitably included in a liquid crystal display device.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<Outline of polarizing plate>
The polarizing plate of the present invention is a polarizing plate in which an optical film A, a polarizer, and an optical film B are laminated in this order, and the optical film A contains at least one of an acrylic resin or a polyester resin. The optical film B is a cellulose acylate resin having an acyl group substitution degree of 2.1 to 2.70 and a structure represented by the formulas (1-1) to (1-3). It is a retardation film containing any of the compounds having the above .

  By setting it as such a structure, the polarizing plate by which generation | occurrence | production of the color nonuniformity and the point-like defect was suppressed can be provided.

  In the present invention, the optical film A is preferably a resin film outside the polarizing plate and functions as a protective film for the polarizing plate. Further, the optical film B is preferably a resin film on the inner side (liquid crystal cell side) of the polarizing plate, and functions as a retardation film.

  The mechanism of action is not clear, but is presumed as follows.

  As an inner resin film (retardation film), a compound having a structure represented by the general formula (1) having a biphenyl skeleton and an ether structure, an ester structure or an amide structure is allowed to coexist with the cellulose acylate resin, thereby making this compound. It is considered that the ether structure, ester structure or amide structure portion of this has an interaction with the side chain and hydrogen atom of the cellulose acylate resin, and the interaction between the cellulose acylate resin and water is weakened. In addition, the hydrophobic structure of the biphenyl skeleton is considered to further weaken the interaction between the cellulose acylate resin and water and suppress the occurrence of phase difference fluctuations due to fluctuations in environmental humidity. As a result, it is estimated that the occurrence of color unevenness in the display device could be suppressed. Therefore, as in the present invention, the outer resin film (protective film) is a film with low moisture permeability, and the inner resin film (retardation film) is a film with high moisture permeability such as cellulose acylate resin. However, it is considered that color unevenness did not occur, and in addition, the occurrence of point defects could be suppressed. In addition, lowering the moisture permeability of the outer resin film (protective film) can also reduce the influence of moisture from the outside, and has the effect of suppressing the occurrence of color unevenness. Therefore, in the present invention, it is considered that both of the color unevenness and the point-like defect of the display device that have been difficult to achieve both of the conventional methods can be solved.

  Hereinafter, the polarizing plate of the present invention will be described in detail.

<< Compound having a structure represented by the general formula (1) >>
The compound having a structure represented by the following general formula (1) is included in the optical film B. By using this compound together with the cellulose acylate resin, when the polarizing plate is used in a liquid crystal display device, the occurrence of phase difference fluctuation due to fluctuations in environmental humidity is suppressed, and the occurrence of color unevenness is suppressed. Point-like defects due to accumulation of moisture can be suppressed.
Furthermore, it can function as a phase difference increasing agent.

In formula, R < ¹ > -R < ⁴ > represents a hydrogen atom or a C1-C3 alkyl group each independently. R ⁵ and R ⁶ each independently represents an alkyl group having a substituent or an aromatic hydrocarbon ring which may have a substituent. The substituent is at least one selected from the group consisting of an epoxy group, a hydroxy group, an alkoxy group, an acyloxy group, and an aromatic group. L ¹ and L ² represent O, C (═O) O, or C (═O) NR. R represents a hydrogen atom or an alkyl group.

In the general formula ^(1), R 1 ~R ⁴ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Here, R ^{1 to} R ⁴ may be the same or different from each other. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Among these, from the viewpoints of improving the retardation value (particularly the retardation value in the thickness direction of the film) and compatibility with cellulose acylate, a hydrogen atom, a methyl group, and an ethyl group are preferable, and a methyl group is preferable. Particularly preferred.

R ⁵ and R ⁶ each independently represents an alkyl group having a substituent or an aromatic hydrocarbon ring which may have a substituent. At this time, R ⁵ and R ⁶ may be the same or different. The substituent is at least one selected from the group consisting of an epoxy group, a hydroxy group, an alkoxy group, an acyloxy group, and an aromatic group. Here, the acyloxy group is represented by the formula: —O—C (═O) —R, where R is a linear or branched alkyl group having 1 to 8 carbon atoms or an aromatic group. The alkyl group and aromatic group are as defined below.

When R ⁵ and R ⁶ are aromatic hydrocarbon rings, they are preferably benzene rings. As the substituent of the aromatic hydrocarbon ring, an alkoxy group and an acyloxy group are preferable. Moreover, it is preferable that an alkoxy group has a C1-C3 alkyl chain, and it is more preferable that it is a methoxy group. The acyloxy group is preferably an acetic acid group or a propionate group.

R ⁵ and R ⁶ are preferably an alkyl group having a substituent.

The substituent for the alkyl group in R ⁵ and R ⁶ preferably has an epoxy group, an acyloxy group, or a hydroxy group. The epoxy group is preferably unsubstituted.

The alkyl group as R ⁵ and R ⁶ is not particularly limited, but is methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group. , A neopentyl group, a hexyl group, a heptyl group, an octyl group, or the like, is preferably a linear or branched alkyl group having 1 to 8 carbon atoms. Among these, a C1-C5 alkyl group is preferable and a C1-C4 alkyl group is more preferable.

  The aromatic group may be an aromatic hydrocarbon ring group having 6 to 24 carbon atoms. More specifically, a phenyl group, p-tolyl group, naphthyl group, biphenyl group, fluorenyl group, anthryl group, pyrenyl group, azulenyl group, acenaphthylenyl group, terphenyl group, phenanthryl group and the like can be mentioned. Of these, a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable. The aromatic ring group may have a substituent. Here, the substituent is not particularly limited, but for example, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a phenyl group, a methylphenyl group, a phenylphenyl group, a methylphenylphenyl group. , Cyano group, halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), nitro group and the like. Moreover, the said substituent may be one, or may be two or more, and in the latter case, each substituent may be the same or different. Among these, from the viewpoints of improving the retardation value (particularly the retardation value in the thickness direction of the film) and compatibility with cellulose acylate, the aromatic group is phenyl group, methylphenyl group, methylphenylphenyl. It is preferably a group.

L ¹ and L ² represent O, C (═O) O, or C (═O) NR. R represents a hydrogen atom or an alkyl group. Although it does not restrict | limit especially as an alkyl group, A C1-C5 alkyl group is preferable.

  The compound having a structure represented by the general formula (1) is preferably a compound having a structure represented by the following general formula (2).

(Wherein R ^{1 to} R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ⁵ and R ⁶ each independently represents an alkyl group having a substituent or a substituent. An aromatic hydrocarbon ring which may have a group, wherein the substituent is at least one selected from the group consisting of an epoxy group, a hydroxy group, an alkoxy group, an acyloxy group, and an aromatic group.
Here, R < ¹ > -R < ⁶ > is synonymous with R < ¹ > -R < ⁶ > in General formula (1), respectively.

When the substituent of the alkyl group in R ⁵ and R ⁶ have the acyloxy group, the production method of general formula (1) and the compound having the structure represented by the general formula (2) is not particularly limited. Specifically, the compound can be obtained by reacting an epoxy compound with an aromatic monocarboxylic acid. As said epoxy compound, the diglycidyl ether type epoxy compound obtained by reaction with biphenols and epichlorohydrin is mentioned. As a specific example of this epoxy compound, 3,3 ′, 5,5′-tetramethyl-4,4′-diglycidyloxybiphenyl (in the commercial product, “jER YX-4000” (manufactured by Japan Epoxy Resin Co., Ltd.) Biphenol type epoxy compounds such as epoxy equivalent 180-192)) can be used.

  Examples of the aromatic monocarboxylic acid include benzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, tetramethylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, cumic acid, o-toluic acid, m-toluic acid, p-toluic acid, anisic acid, ethoxybenzoic acid, propoxybenzoic acid, cyanobenzoic acid, fluorobenzoic acid, nitrobenzoic acid, 4-phenylbenzoic acid, 4- (3-methylphenyl) benzoic acid, 4- (4- Methylphenyl) benzoic acid, 4- (3,5-dimethylphenyl) benzoic acid, 2-methyl-4-phenylbenzoic acid, 2,6-dimethyl-4-phenylbenzoic acid, 2,6-dimethyl-4- ( 3,5-dimethylphenyl) benzoic acid, naphthoic acid, nicotinic acid, furoic acid, 1-naphthalene carboxylic acid, 2-naphthalene carboxylic acid, etc. It is. These aromatic monocarboxylic acids can be used alone or in combination of two or more.

  In the above reaction, the epoxy group of the epoxy compound and the carboxy group of the aromatic monocarboxylic acid react to synthesize a compound having a structure represented by the general formula (1) and the general formula (2). Here, the reaction conditions are not particularly limited as long as the reaction proceeds. For example, the reaction temperature is 80 to 130 ° C, more preferably 100 to 115 ° C. The reaction time is preferably 10 to 25 hours. Further, the mixing ratio (preparation ratio) of the epoxy compound and the aromatic monocarboxylic acid is not particularly limited as long as the reaction proceeds. For example, the ratio of the number of moles of epoxy groups in the epoxy compound to the number of moles of aromatic monocarboxylic acid (number of moles of epoxy group) / (number of moles of aromatic monocarboxylic acid) is 1 / 0.9 to 1.0. It is preferable that it is the range of these.

  In the above reaction, a catalyst may be used as necessary. Examples of the catalyst include phosphine compounds such as trimethylphosphine, triethylphosphine, tributylphosphine, trioctylphosphine, and triphenylphosphine; 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-ethyl-4-methyl Imidazole compounds such as imidazole and 4-phenyl-2-methylimidazole; triethylamine, tributylamine, trihexylamine, triamylamine, triethanolamine, dimethylaminoethanol, tritylenediamine, dimethylphenylamine, dimethylbenzylamine, 2 -Amine compounds such as (dimethylaminomethyl) phenol and 1,8-diazabicyclo (5,4,0) undecene-7; Such as emission compounds. These catalysts are preferably used in an amount of 0.05 to 1 part by mass with respect to 100 parts by mass in total of the epoxy compound and the aromatic monocarboxylic acid.

  Moreover, as a compound which has a structure represented by General formula (2), the compound as described in Unexamined-Japanese-Patent No. 2011-140637 and Unexamined-Japanese-Patent No. 2011-116912 has a structure represented by General formula (2). Included in the compound. More specifically, the following is mentioned as a more preferable example of the compound which has a structure represented by General formula (2). In addition, a compound is prescribed | regulated by the following number. That is, the compound having the structure represented by the following (1-1) is also referred to as “compound (1-1)”.

  Furthermore, the compound which has a structure represented by the following general formula (1a) is also preferable.

(In the formula, each R independently represents a hydrogen atom (H), an acetic acid group (OAc) or a propionate group (OPr).)
In the optical film B according to the present invention, the content of the compound having a structure represented by the general formula (1), the general formula (2), or the general formula (1a) is not particularly limited. The content of the compound having the structure represented by the general formula (1), the general formula (2) or the general formula (1a) is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the cellulose acylate resin, for example. More preferably, it is 1-20 mass parts, Most preferably, it is 2-10 mass parts.

  In addition, as a method for adding the compound having the structure represented by the general formula (1), the general formula (2), or the general formula (1a), the compound that forms the optical film B may be added as a powder. After dissolving in a solvent, it may be added to the resin forming the retardation film.

<< Optical film A >>
The optical film A is an optical film containing at least one of an acrylic resin or a polyester resin. The optical film A is preferably a resin film outside the polarizing plate in the liquid crystal display device as a protective film. Therefore, it is preferable that the optical film A has a low moisture permeability of the protective film.

It is preferable that the water vapor permeability of the optical film A at 40 ° C. and 90% RH is in the range of ^{20 to} 120 g / m ² · 24 hr.

  The water vapor transmission rate can be measured by a method according to JIS K 7129 (1992).

"acrylic resin"
An acrylic resin means a (meth) acrylic resin and is a concept including both an acrylic resin and a methacrylic resin. Hereinafter, the acrylic resin will be described.

(1-1) Acrylic resin The acrylic resin is a (meth) acrylic resin as described above, and means a polymer of acrylic acid ester or methacrylic acid ester. As the polymer of the methacrylic acid ester, for example, a polymer composed mainly of an alkyl methacrylate is preferable. The monomer composition of the alkyl methacrylate is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more, based on a total of 100% by mass of all monomers. And alkyl methacrylate is 99% by mass or less. The acrylic resin may be a homopolymer of alkyl methacrylate or a copolymer of 50% by mass or more of alkyl methacrylate and 50% by mass or less of a monomer other than alkyl methacrylate. Good. As the alkyl methacrylate, those having 1 to 4 carbon atoms of the alkyl group are usually used, and among them, methyl methacrylate is preferably used.

  The monomer other than alkyl methacrylate may be a monofunctional monomer having one polymerizable carbon-carbon double bond in the molecule, or two or more polymerizable carbons in the molecule. -A polyfunctional monomer having a carbon double bond may be used. In particular, monofunctional monomers are preferably used, and examples thereof include alkyl acrylates such as methyl acrylate and ethyl acrylate, and further, such as styrene and alkyl styrene as long as the effects of the present invention are not impaired. Examples include styrene monomers and unsaturated nitriles such as acrylonitrile and methacrylonitrile. When using alkyl acrylate as a copolymerization component, the carbon number is 1-8 normally.

  The acrylic resin preferably does not have a glutarimide derivative, a glutaric anhydride derivative, a lactone ring structure, or the like. These acrylic resins may not provide sufficient mechanical strength and heat-and-moisture resistance as an acrylic resin film.

  The weight average molecular weight of the acrylic resin is preferably in the range of 100,000 to 4000000.

  The weight average molecular weight of the acrylic resin according to the present invention can be measured by gel permeation chromatography. The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
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 Corp.) Mw = 500 to 2800000 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.

(1-2) Rubber elastic particles In order to improve flexibility and handleability, it is preferable that rubber elastic particles are blended in the acrylic resin. The rubber elastic particles are particles containing a rubber elastic body, and may be particles composed only of a rubber elastic body, or may be particles having a multilayer structure having a rubber elastic body layer. Examples of rubber elastic bodies include olefin-based elastic polymers, diene-based elastic polymers, styrene-diene-based elastic copolymers, and acrylic-based elastic polymers. Among these, an acrylic elastic polymer is preferable from the viewpoint of surface hardness, light resistance, and transparency of the acrylic resin film.

  The acrylic elastic polymer is preferably a polymer mainly composed of alkyl acrylate, may be a homopolymer of alkyl acrylate, or may be a single polymer other than alkyl acrylate 50 mass% or more and alkyl acrylate. It may be a copolymer with 50% by mass or less of the monomer. As the alkyl acrylate, those having 4 to 8 carbon atoms in the alkyl group are usually used. Examples of monomers other than alkyl acrylate include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, styrene monomers such as styrene and alkyl styrene, acrylonitrile and methacrylonitrile. Monofunctional monomers such as unsaturated nitriles, alkenyl esters of unsaturated carboxylic acids such as allyl (meth) acrylate and methallyl (meth) acrylate, dialkenyl esters of dibasic acids such as diallyl maleate, And polyfunctional monomers such as unsaturated carboxylic acid diesters of glycols such as alkylene glycol di (meth) acrylate.

  The rubber elastic particle containing the acrylic elastic polymer is preferably a particle having a multilayer structure having an acrylic elastic polymer layer, and a polymer mainly composed of alkyl methacrylate outside the acrylic elastic polymer. It may be a two-layer structure having the above-mentioned layer, or a three-layer structure having a polymer layer mainly composed of alkyl methacrylate inside the acrylic elastic polymer. In addition, the example of the monomer composition of the polymer mainly composed of alkyl methacrylate constituting the layer formed on the outside or inside of the acrylic elastic polymer is the same as the alkyl methacrylate previously mentioned as an example of the acrylic resin. This is the same as the monomer composition example of the main polymer. Such acrylic rubber elastic particles having a multilayer structure can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

  As the rubber elastic particles, those having a number average particle diameter of 10 to 300 nm of the rubber elastic bodies contained therein can be used. Thereby, when an acrylic resin film is laminated | stacked on a polarizing film using an adhesive agent, an acrylic resin film can be made hard to peel from an adhesive bond layer. The number average particle diameter of the rubber elastic body is preferably 50 nm or more and 250 nm or less.

  In the rubber elastic particle in which the outermost layer is a polymer mainly composed of methyl methacrylate and the acrylic elastic polymer is encapsulated in the polymer, when the rubber elastic particle is mixed with the base acrylic resin, the rubber elastic particle The outermost layer is mixed with the base acrylic resin. Therefore, in the cross section, when the acrylic elastic polymer is dyed with ruthenium oxide and observed with an electron microscope, the rubber elastic particles can be observed as particles excluding the outermost layer. Specifically, in the case of using rubber elastic particles having a two-layer structure in which the inner layer is an acrylic elastic polymer and the outer layer is a polymer mainly composed of methyl methacrylate, the inner layer is an acrylic elastic polymer. The portion is dyed and observed as particles having a single layer structure. Further, the rubber elastic particles having a three-layer structure in which the innermost layer is a polymer mainly composed of methyl methacrylate, the intermediate layer is an acrylic elastic polymer, and the outermost layer is a polymer mainly composed of methyl methacrylate. When is used, the center part of the innermost layer particle is not dyed, and only the acrylic elastic polymer part of the intermediate layer is dyed and observed as a two-layered particle.

  In the present specification, the number average particle diameter of the rubber elastic particles is, as described above, when the rubber elastic particles are mixed with the base resin and the cross section is dyed with ruthenium oxide, and is dyed in a substantially circular shape. It is the number average value of the diameters of the parts observed in FIG.

  In the acrylic resin film, the amount of the rubber elastic particles is not particularly limited. For example, 25 to 45% by mass of rubber elastic particles having a number average particle diameter of 10 to 300 nm are mixed in a transparent acrylic resin. Those are preferred.

  The acrylic resin may be produced, for example, by obtaining rubber elastic particles and then polymerizing a monomer as a raw material of the acrylic resin in the presence thereof to produce a base acrylic resin, or rubber. After obtaining the elastic particles and the acrylic resin, they may be produced by mixing them by melt kneading or the like.

  The glass transition temperature Tg of the acrylic resin is preferably in the range of 80 to 120 ° C. Further, the acrylic resin preferably has a high surface hardness when formed into a film, specifically, a pencil hardness (with a load of 500 g, conforming to JIS K 5600-5-4) of B or higher.

  The acrylic resin film preferably has a flexural modulus (JIS K 7171) of 1500 MPa or less from the viewpoint of the flexibility of the acrylic resin. The flexural modulus is more preferably 1300 MPa or less, and still more preferably 1200 MPa or less. This bending elastic modulus varies depending on the type and amount of acrylic resin and rubber elastic particles in the acrylic resin film. For example, the bending elastic modulus generally decreases as the content of rubber elastic particles increases. In addition, the flexural modulus is generally smaller when an acrylic resin is a copolymer of alkyl methacrylate and alkyl acrylate than a homopolymer of alkyl methacrylate.

  In addition, the elastic elastic polymer particles having the two-layer structure are generally used as the elastic rubber particles, rather than the acrylic elastic polymer particles having the two-layer structure. In general, the flexural modulus is smaller when the acrylic elastic polymer particles having a layer structure are used. Further, in the rubber elastic body particles, as the average particle diameter of the rubber elastic body is smaller or the amount of the rubber elastic body is larger, the bending elastic modulus is generally smaller. Therefore, it is preferable to adjust the kind and amount of acrylic resin and rubber elastic body particles within the predetermined range so that the flexural modulus is 1500 MPa or less.

  When the acrylic resin film has a multilayer structure, the layer that can exist other than the layer of the acrylic resin composition is not particularly limited in its composition. For example, it is an acrylic resin that does not contain rubber elastic particles or a layer of the composition. It may be a layer made of an acrylic resin in which the content of the rubber elastic body particles and the average particle diameter of the rubber elastic body in the rubber elastic body particles are outside the above-mentioned regulations.

  Typically, it has a two-layer or three-layer structure, for example, a two-layer structure including an acrylic resin layer / an acrylic resin not containing rubber elastic particles or a layer of the composition thereof, or an acrylic resin. A three-layer structure comprising an acrylic resin not containing rubber elastic particles or a composition layer / acrylic resin composition layer may be employed. What is necessary is just to let the surface of the layer of an acrylic resin composition be a bonding surface with a polarizing film in the multilayered acrylic resin film.

  Moreover, when making an acrylic resin film into a multilayer structure, you may mutually differ content of rubber elastic-body particle | grains or each layer of the said compounding agent. For example, a layer containing an ultraviolet absorber and / or an infrared absorber and a layer not containing an ultraviolet absorber and / or an infrared absorber may be laminated with this layer interposed therebetween. Further, the content of the ultraviolet absorber in the acrylic resin composition layer may be higher than the content of the ultraviolet absorber in the acrylic resin or the composition layer containing no rubber elastic particles, Specifically, the former is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass, and the latter is preferably 0 to 1% by mass, more preferably 0 to 0.5% by mass. Thus, ultraviolet rays can be efficiently blocked without deteriorating the color tone of the polarizing plate, and a decrease in the degree of polarization during long-term use can be prevented.

  The acrylic resin film may be non-oriented or unstretched, or may be stretched. When the stretching treatment is not performed, the thickness of the polarizing plate is likely to increase because the thickness is increased. On the other hand, the handling property of the acrylic resin film is improved because the thickness is increased. Such an acrylic resin film can be obtained from an unstretched film (raw film) obtained by forming an acrylic resin composition. On the other hand, when stretched, it is easy to develop a phase difference, but stretching has an advantage that the thickness of the acrylic resin film is reduced and the rigidity is improved. The stretched film can be produced by stretching an unstretched film by an arbitrary method.

  The acrylic resin can be formed into an unstretched film by any method. This unstretched film is preferably transparent and substantially free of in-plane retardation. Examples of the film forming method include an extrusion method in which a molten resin is extruded to form a film, and a solvent cast method in which a solvent dissolved in an organic solvent is cast on a flat plate and then the solvent is removed to form a film. Etc. can be adopted.

  As a specific example of the extrusion molding method, for example, there is a method of forming a film in a state where the acrylic resin composition is sandwiched between two rolls. At this time, by varying the rigidity of the roll surface, it is possible to make one surface of the acrylic resin film smooth and the other surface rough.

  As a specific example of the extrusion molding method, for example, there is a method of forming a film in a state where the acrylic resin composition is sandwiched between two metal rolls. In this case, the metal roll is preferably a mirror roll. Thereby, the unstretched film excellent in surface smoothness can be obtained. In addition, when obtaining the thing of a multilayer structure as the optical film A, the said acrylic resin composition should just be formed into a film after multilayer extrusion with another acrylic resin composition. The thickness of the unstretched film thus obtained is preferably 5 to 200 μm, more preferably 10 to 85 μm.

<Polyester resin>
The polyester resin that forms the optical film A is not particularly limited. For example, terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1 , 5-Naphthalenedicarboxylic acid, diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracene dicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid , Hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyl Adipi Dicarboxylic acids such as acid, pimelic acid, azelaic acid, dimer acid, sebacic acid, suberic acid, dodecadicarboxylic acid, ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1, 4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis (4-hydroxyphenyl) propane , A diol such as bis (4-hydroxyphenyl) sulfone, a homopolymer obtained by polycondensation of one kind each, a copolymer obtained by polycondensation of one or more dicarboxylic acids and two or more diols, or a dicarboxylic acid Two or more kinds and one or more kinds of diols are polycondensed Copolymers, and it can include any of the polyester resin of these homopolymers and copolymers of two or more blend formed by blending resin. Of these, polyethylene terephthalate resin is preferably used. Further, the above resins can be mixed and used.

  The polyester film is obtained by, for example, a method of forming the film by melt-extruding the above-described polyester resin into a film and cooling and solidifying with a casting drum. As the polyester film in the polarizing plate of the present invention, any of an unstretched film and a stretched film can be used. For example, when a film having a small birefringence is required, an unstretched film can be suitably used. In addition, when birefringence is used for optical compensation of a liquid crystal display device, a stretched film can be suitably used. A stretched film, particularly a biaxially stretched film, is also preferably used from the viewpoint of strength.

  Polyester film is more durable than TAC (triacetylcellulose) film, but unlike TAC film, it has birefringence, so when it is used as a polarizer protective film, it has a rainbow-like color when observed from an oblique direction. Unevenness occurs and image quality deteriorates.

  For this reason, it is preferable that at least one of the optical films A containing a polyester resin is a polyester film having an in-plane retardation of 3000 to 30000 nm. At this time, the polarizer protective film on the exit light side of the polarizing plate disposed on the exit light side with respect to the liquid crystal cell is preferably a film made of a polyester film having a retardation of 3000 to 30000 nm. The ratio value (Ro / Rt) of the in-plane retardation (Ro) and the thickness direction retardation (Rt) of the polyester film is preferably 0.2 or more. With such a configuration, it is possible to obtain a spectrum that approximates the light source at any observation angle, and it is possible to ensure good visibility without rainbow-like color unevenness. Moreover, the mechanical strength suitable for optical film A thinning can be provided.

  As such a polyester resin, polyethylene terephthalate or polyethylene naphthalate can be used, but other copolymer components may be included. These resins are excellent in transparency and excellent in thermal and mechanical properties, and the retardation can be easily controlled by stretching. In particular, polyethylene terephthalate is the most suitable material because it has a large intrinsic birefringence and a relatively large retardation can be obtained even if the film is thin.

  The retardation can be obtained by measuring the biaxial refractive index and thickness, or by using a commercially available automatic birefringence measuring device such as KOBRA-21ADH (Oji Scientific Instruments). it can.

  The optical film A containing a polyester resin that is a protective film according to the present invention can be manufactured according to a general method for manufacturing a polyester film. For example, the polyester resin is melted and the non-oriented polyester extruded and formed into a sheet shape is stretched in the longitudinal direction by utilizing the speed difference of the roll at a temperature equal to or higher than the glass transition temperature, and then stretched in the transverse direction by a tenter. The method of performing heat processing is mentioned.

  The polyester film according to the present invention may be a uniaxially stretched film or a biaxially stretched film, but when the biaxially stretched film is used as a polarizer protective film, it is observed from directly above the film surface. Although no rainbow-like color unevenness is observed, rainbow-like color unevenness may be observed when observed from an oblique direction.

  This phenomenon is because the biaxially stretched film consists of refractive index ellipsoids having different refractive indexes in the running direction, width direction, and thickness direction, and the in-plane retardation is zero due to the light transmission direction inside the film. This is because there exists a direction in which the refractive index ellipsoid appears to be a perfect circle. Therefore, when the liquid crystal display screen is observed from a specific oblique direction, a point where the retardation in the in-plane direction becomes zero may occur, and rainbow-like color unevenness occurs concentrically around that point. Become. When the angle from the position directly above the film surface (normal direction) to the position where the rainbow-like color unevenness can be seen is θ, this angle θ becomes larger as the birefringence in the film surface becomes larger. Unevenness is difficult to see. Since the angle θ tends to be small in the biaxially stretched film, the uniaxially stretched film is more preferable because rainbow-like color unevenness is less visible.

  However, a perfect uniaxial (uniaxial symmetry) film is not preferable because the mechanical strength in the direction orthogonal to the orientation direction is significantly reduced. The present invention has biaxiality (biaxiality) in a range that does not substantially cause rainbow-like color unevenness or a range that does not cause rainbow-like color unevenness in the viewing angle range required for a liquid crystal display screen. It is preferable.

  As a means for suppressing the occurrence of color unevenness while maintaining the mechanical strength of the protective film, the ratio of the retardation (retardation in the in-plane direction) value of the protective film to the retardation (Rt) value in the thickness direction It is preferable to control so that the value falls within a specific range. The smaller the difference between the in-plane retardation and the retardation in the thickness direction, the more isotropic the birefringence action due to the observation angle, so the change in retardation due to the observation angle becomes smaller. For this reason, it is considered that rainbow-like color unevenness due to the observation angle hardly occurs.

  The ratio value (Ro / Rt) of the retardation in the in-plane direction and the retardation in the thickness direction of the polyester film according to the present invention is preferably 0.2 or more, more preferably 0.5 or more, and still more preferably 0. .6 or more. The larger the ratio of the in-plane retardation to the retardation in the thickness direction (Ro / Rt), the more isotropic the birefringence action becomes, and the less rainbow-like color unevenness occurs depending on the observation angle. . In a complete uniaxial (uniaxial symmetry) film, the ratio value (Ro / Rt) of the retardation in the in-plane direction to the retardation in the thickness direction is 2.0. However, as described above, the mechanical strength in the direction orthogonal to the orientation direction is significantly lowered as the film approaches a complete uniaxial (uniaxial symmetry) film.

  On the other hand, the ratio value (Ro / Rt) of the retardation in the in-plane direction and the retardation in the thickness direction of the polyester film according to the present invention is preferably 1.2 or less, more preferably 1.0 or less. In order to completely suppress the occurrence of rainbow-like color unevenness due to the observation angle, the ratio value (Ro / Rt) between the retardation in the in-plane direction and the thickness direction phase difference need not be 2.0, 1.2 or less is sufficient. Even if the ratio is 1.0 or less, it is possible to satisfy the viewing angle characteristics (180 degrees left and right, 120 degrees up and down) required for the liquid crystal display device.

  Describing specifically the film forming conditions of the polyester film according to the present invention, the longitudinal stretching temperature and the transverse stretching temperature are preferably from 80 to 130 ° C, particularly preferably from 90 to 120 ° C. The longitudinal draw ratio is preferably 1.0 to 3.5 times, particularly preferably 1.0 to 3.0 times. The transverse draw ratio is preferably 2.5 to 6.0 times, and particularly preferably 3.0 to 5.5 times. In order to control the retardation within the above range, it is preferable to control the ratio of the longitudinal draw ratio and the transverse draw ratio. If the difference between the vertical and horizontal draw ratios is too small, it is difficult to increase the retardation, which is not preferable. Also, setting the stretching temperature low is a preferable measure for increasing the retardation. In the subsequent heat treatment, the treatment temperature is preferably from 100 to 250 ° C, particularly preferably from 180 to 245 ° C.

  In order to suppress the fluctuation of the retardation, it is preferable that the thickness unevenness of the film is small. Since the stretching temperature and the stretching ratio greatly affect the thickness unevenness of the film, it is necessary to optimize the film forming conditions from the viewpoint of the thickness unevenness. In particular, when the longitudinal stretching ratio is lowered to increase the retardation, unevenness in the longitudinal thickness may be deteriorated. Since there is a region where the vertical thickness unevenness becomes extremely worse within a specific range of the draw ratio, it is desirable to set the film forming conditions outside this range.

  The thickness unevenness of the film of the present invention is preferably 5.0% or less, more preferably 4.5% or less, still more preferably 4.0% or less, and 3.0% or less. It is particularly preferred that

  As described above, in order to control the retardation of the film within a specific range, the stretching ratio, the stretching temperature, and the thickness of the film can be appropriately set. For example, the higher the stretching ratio, the lower the stretching temperature, and the thicker the film, the higher the retardation. Conversely, the lower the stretching ratio, the higher the stretching temperature, and the thinner the film, the lower the retardation. However, when the thickness of the film is increased, the thickness direction retardation tends to increase. Therefore, it is desirable to set the film thickness appropriately in the range described later. In addition to controlling the retardation, it is necessary to set final film forming conditions in consideration of physical properties necessary for processing.

  Although the thickness of the polyester film concerning this invention is arbitrary, the range of 15-300 micrometers is preferable, More preferably, it is the range of 15-200 micrometers. Even with a film thickness of less than 15 μm, it is possible in principle to obtain a retardation of 3000 nm or more. However, in that case, the anisotropy of the mechanical properties of the film becomes remarkable, and the film tends to be torn or torn, and the practicality as an industrial material may be lowered. A particularly preferable lower limit of the thickness is 25 μm. On the other hand, if the upper limit of the thickness of the polarizer protective film exceeds 300 μm, the thickness of the polarizing plate increases. From the viewpoint of practicality as a polarizer protective film, the upper limit of the thickness is preferably 200 μm. A particularly preferable upper limit of the thickness is 100 μm, which is about the same as a general TAC film. In order to control the retardation within the range of the present invention even in the above thickness range, polyethylene terephthalate is suitable as the polyester used as the film substrate.

  The film thickness of the optical film A according to the present invention is preferably in the range of 10 to 90 nm. More preferably, it exists in the range of 10-40 nm.

  Various additives may be used in the optical film A according to the present invention. Examples of other additives include plasticizers, ultraviolet absorbers, fluorine-based surfactants, release agents, matting agents, deterioration preventing agents, optical anisotropy control agents, infrared absorbers, and the like. Can be used.

<< Optical film B >>
The optical film B has a structure represented by the formulas (1-1) to (1-3) and a cellulose acylate resin having an acyl group substitution degree in the range of 2.1 to 2.70. A retardation film containing any one of the compounds having

<Cellulose acylate resin>
The cellulose acylate resin constituting the optical film B according to the present invention is a cellulose acylate resin having an acyl group substitution degree in the range of 2.1 to 2.70 .

  Examples of the raw material cellulose include cotton linter and wood pulp (hardwood pulp, softwood pulp). Cellulose acylate obtained from any raw material cellulose can be used, and in some cases, it may be mixed and used. Detailed descriptions of these raw material celluloses can be found in, for example, Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, published by Nikkan Kogyo Shimbun (published in 1970), and the Japan Society of Invention and Innovation Technical Bulletin No. 2001. The cellulose described in No.-1745 (pages 7 to 8) can be used.

  The optical film B is a cellulose acylate resin having an acyl group substitution degree in the range of 2.1 to 3.0. The cellulose acylate resin is preferably a cellulose acetate having an acetyl group substitution degree in the range of 2.1 to 2.7, more preferably a cellulose acetate having an acetyl group substitution degree in the range of 2.6 to 2.7. It is.

  The total substitution degree of the acyl group is preferably 2.1 to 3.0, more preferably 2.1 to 2.7 from the viewpoint of improving water resistance. Alternatively, from the viewpoint of improving the castability and stretchability during film formation and further improving the uniformity of the film thickness, the total substitution degree of acyl groups of cellulose acylate is 2.1 to 2.5. It is preferable.

  The cellulose acylate resin according to the present invention is preferably at least one selected from cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate benzoate, cellulose propionate, and cellulose butyrate. Among these, more preferred cellulose acylate resins are cellulose acetate, cellulose acetate propionate, and triacetyl cellulose.

  In addition, the substitution degree of an acetyl group and the substitution degree of other acyl groups can be obtained by a method prescribed in ASTM-D817-96.

  The weight average molecular weight (Mw) of the cellulose acylate resin according to the present invention is preferably 75,000 or more, more preferably in the range of 75,000 to 300,000, still more preferably in the range of 100,000 to 24,000, and 160000. Those of ˜24,000 are particularly preferred. If the weight average molecular weight (Mw) of the cellulose acylate resin is 75000 or more, the self-film-forming property and adhesion improving effect of the cellulose acylate layer itself are exhibited, which is preferable. In the present invention, two or more kinds of cellulose acylate resins can be mixed and used.

(Measurement of retardation value and retardation value)
The retardation value Ro in the in-plane direction and the retardation value Rt in the thickness direction of the optical film B according to the present invention are preferably in the following ranges, respectively, in an environment of 23 ° C. and 55% RH. By setting the retardation value within such a range, a polarizing plate having good polarization characteristics can be obtained.

Ro: 20 to 130 nm
Rt: 100 to 300 nm
The retardation value can be measured at an optical wavelength of 590 nm using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments).

Specifically, 23 ° C. The optical film, in an environment of 55% RH, for 3-dimensional refractive index measured at 10 points at a wavelength of 590 nm, the refractive indices _{n x,} n y, the average value of _{n z} After obtaining, the retardation value Ro in the in-plane direction and the retardation value Rt in the thickness direction can be calculated according to the following formulas (i) and (ii).

Formula (i): Ro (590) = (n x -n y) × d
Formula (ii): Rt (590) = {(n _x + n _y ) / 2−n _z } × d
In [Equation (i) and Formula (ii), n _x represents a refractive index in the direction x in which the refractive index is maximized in the plane direction of the film. n _y, in-plane direction of the film, the refractive index in the direction y perpendicular to the direction x. _nz represents the refractive index in the thickness direction z of the film. d represents the thickness (nm) of the film. ]
The film thickness of the optical film B according to the present invention is preferably in the range of 10 to 90 nm. More preferably, it exists in the range of 10-40 nm.

<Phase difference increasing agent>
The optical film B according to the present invention can contain a retardation increasing agent. The phase difference increasing agent is preferably a nitrogen-containing phase difference increasing agent. Specifically, the nitrogen-containing retardation increasing agent is preferably at least one selected from compounds having a carbazole ring, a quinoxaline ring, a benzoxazole ring, an oxadiazole ring, an oxazole ring, a triazole ring, and a pyrazole ring. .

  As the phase difference increasing agent, for example, compounds having structures represented by the following general formula (3), general formula (4), and general formula (5) to general formula (9) are preferable.

(Compound having a structure represented by the general formula (3))
The optical film B of the present invention preferably contains a compound represented by the following general formula (3) as a nitrogen-containing retardation increasing agent.

In the general formula (3), A ₁ , A ₂ and B are each independently an alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl). Group), a cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), an aromatic hydrocarbon ring or an aromatic heterocyclic ring. Among these, an aromatic hydrocarbon ring or an aromatic heterocyclic ring is preferable, and a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring having a NICS value smaller than or equal to that of the benzene ring is particularly preferable.

  The NICS value is an index used for quantification of aromaticity by magnetic properties. If the ring is aromatic, the ring current effect strongly shields the center of the ring, and if the ring is antiaromatic, Shielded. Depending on the magnitude of the NICS value, it is possible to determine the strength of the ring current, that is, the degree of contribution of π electrons to the aromaticity of the ring.

  The aromatic compound represented by the general formula (3) having at least three specific aromatic rings having a specific NICS value and having the aromatic rings closely connected to each other is a water adsorbent such as cellulose acylate. The CH / π interaction functions between the CH portion of the resin and the π electron of the aromatic compound. Therefore, rather than the interaction between the water molecule and the water-soluble resin, the compound represented by the general formula (3) and the resin The interaction becomes stronger, and as a result, water can be prevented from entering between the water-adsorbing resin and the additive, and fluctuations in optical properties can be suppressed.

  Here, the NICS value is calculated using Gaussian 03 (Revision B.03, US Gaussian software). Specifically, from the structure optimized using B3LYP (density functional method) as a calculation method and 6-31 + G (a function obtained by adding a diffusion gauss function to a split valence basis set) as a basis function, an NMR shielding constant is obtained. It is calculated by a calculation method (GIAO).

  The NICS values in typical ring structures calculated using this method are shown in Table 1 below.

  If the NICS value is smaller than or equal to the benzene ring, the structure of the 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring is not limited. For example, benzene ring, pyrrole ring, pyrazole ring, imidazole ring, 2,3-triazole ring, 1,2,4-triazole ring, tetrazole ring, furan ring, oxazole ring, isoxazole ring, oxadiazole ring, isoxadiazole ring, thiophene ring, thiazole ring, isothiazole ring, Examples include thiadiazole rings and isothiadiazole rings.

The 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle which is a NICS value of the benzene ring represented by A ₁ , A ₂ and B may have a substituent. As, for example, 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), alkynyl group (ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (phenyl group, p-tolyl group, naphthyl group, etc.) Group), aromatic heterocyclic groups (2-pyrrole group, 2-furyl group, 2-thienyl group, pyrrole group, imidazolyl group, oxazolyl group, thiazolyl group, benzoimidazolyl group, benzoxazolyl group, 2-benzothiazolyl group) 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-thiodiazole 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 group (phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.) ), Acyloxy group (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 group, etc.), acylamino group (formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group etc.), alkyl and arylsulfonylamino groups (methylsulfonylamino group, Spotted Rusulfonylamino group, phenylsulfonylamino 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, p-chlorophenylthio group, m-methoxyphenylthio group, etc.), sulfamoyl group (N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethyl Sulfamoyl 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-methyl Carbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group and the like.

In the general formula (3), A ₁ , A ₂ and B represent a benzene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a 1,2,3-triazole ring or a 1,2,4-triazole ring. It is preferable because a resin composition having excellent optical property variation effects and excellent durability can be obtained.

In the general formula (3), T ₁ and T ₂ preferably each independently represent a pyrrole ring, a pyrazole ring, an imidazole ring, a 1,2,3-triazole ring, or a 1,2,4-triazole ring. . Among these, a pyrazole ring or a 1,2,4-triazole ring is preferable because a resin composition particularly excellent in the effect of suppressing fluctuation in optical properties and particularly excellent in durability can be obtained. It is particularly preferred that The pyrazole ring, imidazole ring, 1,2,3-triazole ring or 1,2,4-triazole ring represented by T ₁ and T ₂ may be a tautomer. Specific structures of the pyrrole ring, pyrazole ring, imidazole ring, 1,2,3-triazole ring or 1,2,4-triazole ring are shown below.

In the formula, * represents a bonding position with L ₁ , L ₂ , L ₃ or L ₄ . R ⁵ represents a hydrogen atom or a non-aromatic substituent. Examples of the non-aromatic substituent represented by R5 include the same groups as the non-aromatic substituent among the substituents that A1 in General Formula (3) may have. When the substituent represented by R5 is an aromatic group-containing substituent, A ₁ and T ₁ or B and T ₁ are easily twisted, and A ₁ , B, and T ₁ are CH / π mutual with the water adsorbent resin. Since it becomes impossible to form an action, it is difficult to suppress fluctuations in optical characteristics. In order to enhance the effect of suppressing fluctuations in optical properties, R ⁵ is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 5 carbon atoms, and particularly preferably a hydrogen atom.

In the general formula (3), T ₁ and T ₂ may have a substituent, and examples of the substituent include a substituent that A ₁ and A ₂ in the general formula (3) may have Similar groups can be mentioned.

In the general formula (3), L ₁ , L ₂ , L ₃ and L ₄ each independently represent a single bond or a divalent linking group, and are 5 or 6 via 2 or less atoms. Membered aromatic hydrocarbon rings or aromatic heterocycles are linked. The term “via two or less atoms” refers to the minimum number of atoms existing between the connected substituents among the atoms constituting the linking group. The divalent linking group having 2 or less linking atoms is not particularly limited, but includes an alkylene group, an alkenylene group, an alkynylene group, O, (C═O), NR, S, and (O═S═O). It is a divalent linking group selected from the group consisting of or a linking group in which two of them are combined. 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 (3) and ₁ and a ₂ have include the same groups as also substituents.

In the general formula (3), L ₁ , L ₂ , L ₃ and L ₄ are CH / π mutual with the water-adsorbing resin by increasing the planarity of the compound represented by the general formula (3). Since the action becomes stronger and fluctuations in optical properties are suppressed, a single bond or O, (C═O) —O, O— (C═O), (C═O) —NR or NR— (C ═O), and more preferably a single bond.

In the said General formula (3), 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 (3) may be the same or different. As n is larger, the CH / π interaction between the compound represented by the general formula (3) and the water-adsorbing resin becomes stronger, so that the effect of suppressing fluctuation in optical properties is better. Excellent compatibility with functional resin. For this reason, it is preferable that n is an integer of 1-3, and it is more preferable that it is an integer of 1-2.

<Compound represented by formula (4)>
The compound represented by the general formula (3) is preferably a compound represented by the general formula (4).

(In the formula, 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 in the general formula (3). _{1, L} 2, _{L 3} and _{L 4} as synonymous .A ₃ and _{T 3,} .L ₅ and _{L 6} represent the same group as _{a 1} and _{T 1} in the general formula (3), respectively, the general Represents the same group as L ₁ in Formula (3), Q ₁ , Q ₂ , Q ₃ and Q ₄ represent a carbon atom or a nitrogen atom, and m represents an integer of 0 to _4. )
Since the smaller m is excellent in compatibility with the cellulose acylate, m is preferably an integer of 0 to 2, and more preferably an integer of 0 to 1.

<Compound having a structure represented by the general formula (3.1)>
The compound having a structure represented by the general formula (3) is preferably a triazole compound having a structure represented by the following general formula (3.1).

_(Wherein, A 1, B, _{L 1} and _{L 2,} .k representing the _A 1, B, the same group as _{L 1} and _{L 2} in formula (3) represents an integer of 1 to 4 T ₁ represents a 1,2,4-triazole ring.)
Furthermore, the triazole compound having a structure represented by the general formula (3.1) is preferably a triazole compound having a structure represented by the following general formula (3.2).

(In the formula, Z represents a structure represented by the following general formula (3.2a). Q represents an integer of 2 to 3. At least two Zs represent at least one Z substituted on a benzene ring. Bonded to ortho or meta position.)

(In the formula, R ¹⁰ represents a hydrogen atom, an alkyl group or an alkoxy group. P represents an integer of 1 to 5. * represents a bonding position with a benzene ring. T ₁ represents a 1,2,4-triazole ring. Represents.)
The compound represented by the general formula (3), (4), (3.1) or (3.2) 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 are those in which the acidic moiety present in the parent compound is a metal ion (eg, an alkali metal salt, such as sodium or potassium salt, an alkaline earth metal salt, such as calcium or magnesium salt, an ammonium salt, an alkali metal ion, alkaline earth And salts formed when substituted with organic bases (ethanolamine, diethanolamine, triethanolamine, morpholine, piperidine, etc.) 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 (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 it adds the compound represented by the said General formula (3), (4), (3.1) or (3.2) in the form which does not contain water, a solvent, and a salt, resin in this invention Hydrates, solvates or salts may be formed in the composition or optical film.

  The molecular weight of the compound represented by the general formula (3), (4), (3.1) or (3.2) is not particularly limited, but the smaller it is, the better the compatibility with the resin is. Since the effect of suppressing fluctuations in the optical value with respect to the change is high, it is preferably 150 to 2000, more preferably 200 to 1500, and even more preferably 300 to 1000.

  Specific examples of the compound having a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle according to the present invention are shown below. Among these, compounds represented by the general formula (3), (4), (3.1) or (3.2) are preferable. The compound having a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring that can be used in the present invention is not limited by the following specific examples. As described above, the following specific examples may be tautomers, and may form hydrates, solvates or salts.

  Next, a method for synthesizing the compound represented by the general formula (3) will be described.

The compound represented by the general formula (3) can be synthesized by a known method.
In the compound represented by the general formula (3), any raw material may be used as the compound having a 1,2,4-triazole ring. However, there is a method of reacting a nitrile derivative or imino ether derivative with a hydrazide derivative. preferable. The solvent used for the reaction may be any solvent as long as it does not react with the raw material, but may be any ester type (eg, ethyl acetate, methyl acetate), amide type (dimethylformamide, dimethylacetamide, etc.), ether type (Ethylene glycol dimethyl ether, etc.), alcohols (eg, methanol, ethanol, propanol, isopropanol, n-butanol, 2-butanol, ethylene glycol, ethylene glycol monomethyl ether, etc.), aromatic hydrocarbons (eg, toluene, xylene, etc.) ), Water can be mentioned. 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 represented by the general formula (3) is crystallized, there is no particular limitation, but a method of crystallizing by adding water to the neutralized reaction solution, or a compound represented by the general formula (3) A method of crystallization by neutralizing an aqueous solution in which is dissolved.

  For example, Exemplary Compound 1 can be synthesized by the following scheme.

(Synthesis of Exemplified Compound 1)

  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 1. The yield was 70% based on benzoylhydrazine.

The ¹ H-NMR spectrum of the obtained exemplary compound 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 6)
Exemplary compound 6 can be synthesized by 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 the mixture was stirred at room temperature for 3 hours, and then the precipitated solid was separated by filtration 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 6. The yield was 77% based on 1,3-dicyanobenzene.

The ¹ H-NMR spectrum of the obtained Exemplified Compound 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)
(Synthesis of Exemplary Compound 176)
Exemplary compound 176 can be synthesized according to the following scheme.

  To 520 ml of dehydrated tetrahydrofuran was added 80 g (0.67 mol) of acetophenone and 52 g (0.27 mol) of dimethyl isophthalate. . After stirring for 3 hours under ice-water cooling, the mixture was stirred for 12 hours under water-cooling. Concentrated sulfuric acid was added to the reaction solution for neutralization, and then pure water and ethyl acetate were added 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. 55.2 g of intermediate A was obtained by adding methanol to the obtained crude crystal and suspending and washing it.

  Intermediate A 55 g (0.15 mol) was added to tetrahydrofuran 300 ml and ethanol 200 ml, and 18.6 g (0.37 mol) of hydrazine monohydrate was added dropwise little by little while stirring at room temperature. After completion of dropping, the mixture was heated to reflux for 12 hours. Pure water and ethyl acetate were added to the reaction solution 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 obtained crude crystals were purified by silica gel chromatography (ethyl acetate / heptane) to obtain 27 g of Exemplified Compound 176.

The ¹ H-NMR spectrum of the obtained exemplary compound 176 is as follows. In order to avoid complication of chemical shift due to the presence of tautomers, the measurement was performed by adding a few drops of trifluoroacetic acid to the measurement solvent.

¹ H-NMR (400 MHz, solvent: heavy DMSO, standard: tetramethylsilane) δ (ppm): 8.34 (1H, s), 7.87-7.81 (6H, m), 7.55-7 .51 (1H, m), 7.48-7.44 (4H, m), 7.36-7.33 (2H, m), 7.29 (1H, s)
Other compounds can be synthesized by the same method.

<About the usage method of the compound represented by General formula (3)>
The compound represented by the general formula (3) according to the present invention can be appropriately adjusted to be contained in the optical film, but the addition amount is a resin that forms the optical film (for example, cellulose acylate) ) To 1 to 15% by mass, and particularly preferably 2 to 10% by mass. 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 optical film of the present invention.

  In addition, as a method for adding the compound represented by the general formula (3), it may be added to the resin forming the optical film as a powder, or after being dissolved in a solvent, it is added to the resin forming the optical film. May be.

  Moreover, the compound in which a nitrogen-containing phase difference increasing agent has a carbazole ring, a quinoxaline ring, a benzoxazole ring, and an oxadiazole ring is preferable.

  Preferred examples of the retardation increasing agent include compounds having structures represented by the following general formulas (5) to (9).

(In the formula, each R independently represents a hydrogen atom (H), an acetic acid group (OAc) or a propionate group (OPr).)

(In the formula, R represents an aliphatic alcohol group having 1 to 20 carbon atoms.)

(In the formula, each R represents an aryl group having 6 to 20 carbon atoms which contains or does not contain a hetero atom. R 'represents hydrogen or an aliphatic alkyl group having 1 to 20 carbon atoms.)

(In the formula, R represents a substituted or unsubstituted aliphatic group having 1 to 20 carbon atoms, or a substituted or unsubstituted aromatic group having 6 to 20 carbon atoms.)

(In the formula, R and R ′ each represent an aliphatic alkyl group having 1 to 20 carbon atoms. The difference in molecular weight between R and R ′ is 20 to 200.)

(In the formula, R ″ represents an aliphatic alkyl group having 1 to 20 carbon atoms.)
The compound having the structure represented by the general formula (3) to the general formula (10) according to the present invention can be appropriately adjusted and contained in the optical film B. It is preferable to contain 1-15 mass% with respect to the acylcellulose resin to form, and it is preferable to contain 2-10 mass% 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 optical film of the present invention.

  Moreover, as a method for adding the compound having the structure represented by the general formula (3) to the general formula (10), the compound may be added to the resin forming the optical film as a powder, and after being dissolved in a solvent, You may add to resin which forms an optical film.

  Various additives may be used for the optical film B according to the present invention. Examples of other additives include plasticizers, ultraviolet absorbers, fluorine-based surfactants, release agents, matting agents, deterioration preventing agents, optical anisotropy control agents, infrared absorbers, and the like. Can be used.

(Plasticizer)
In the present invention, a plasticizer may be used to impart flexibility to the optical film A, improve dimensional stability, and improve moisture resistance.

  As the plasticizer for the optical film, a plasticizer having an octanol / water partition coefficient (log P value) of 0 to 10 is particularly preferably used. If the log P value of the compound is 10 or less, the compatibility with the polymer is good, and there is no problem such as cloudiness or powder blowing of the film. If the log P value is 0 or more, the hydrophilicity becomes high. Since it is not too much, it is difficult to cause adverse effects such as deterioration of the water resistance of the polymer. As the logP value, a more preferable range is 1 to 8, and a particularly preferable range is 2 to 7.

  The octanol / water partition coefficient (log P value) can be measured by a flask immersion method described in Japanese Industrial Standard (JIS) Z 7260-107 (2000).

  Examples of the plasticizer that is preferably added include low-molecular to oligomeric compounds having a molecular weight of about 190 to 5,000 within the above physical properties. For example, phosphoric acid esters, carboxylic acid esters, polyol esters, and the like are used.

  Examples of phosphate esters include triphenyl phosphate (TPP), tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate, trioctyl phosphate (TOP), tributyl phosphate and the like. Triphenyl phosphate and biphenyl diphenyl phosphate are preferable.

  Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of the phthalic acid ester include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diphenyl phthalate, diethyl hexyl phthalate and the like. Examples of the citrate ester include O-acetyl triethyl citrate, O-acetyl tributyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate.

  These preferred plasticizers are liquid except for TPP (melting point: about 50 ° C.) at 25 ° C., and the boiling point is 250 ° C. or higher.

  Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Examples of glycolic acid esters include triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, methyl phthalyl methyl glycolate, propyl phthalyl Examples include propyl glycolate, butyl phthalyl butyl glycolate, and octyl phthalyl octyl glycolate.

  JP-A-5-194788, JP-A-60-250053, JP-A-4-227941, JP-A-6-16869, JP-A-5-271471, JP-A-7-286068. JP-A-5-5047, JP-A-11-80381, JP-A-7-20317, JP-A-8-57879, JP-A-10-152568, and JP-A-10-120824. Plasticizers described in publications and the like are also preferably used. According to these publications, there are many preferable descriptions regarding not only examples of plasticizers but also their usage or characteristics, and they are preferably used in the present invention.

  Other plasticizers include dipentaerythritol esters described in JP-A No. 11-124445, glycerol esters described in JP-A No. 11-246704, diglycerol esters described in JP-A No. 2000-63560, and the like. Citric acid esters described in Kaihei 11-92574, substituted phenyl phosphates described in JP-A-11-90946, ester compounds containing an aromatic ring and a cyclohexane ring described in JP-A 2003-165868, etc. Is preferably used.

  A polymer plasticizer having a resin component having a molecular weight of 1,000 to 100,000 is also preferably used. For example, polyesters and / or polyethers described in JP-A-2002-22956, polyester ethers, polyester urethanes or polyesters described in JP-A-5-97073, copolyester ethers described in JP-A-2-292342, Examples thereof include an epoxy resin or a novolac resin described in JP-A No. 2002-146044.

  Moreover, as a plasticizer which is excellent in terms of volatility, bleed out, low haze and the like, it is preferable to use, for example, a polyester diol described in JP 2009-98674 A, in which both ends are hydroxy groups. Moreover, as a plasticizer which is excellent in terms of flatness and low haze of the optical film, sugar ester derivatives described in WO2009 / 031464 are also preferable. Furthermore, aromatic terminal polyester compounds and polyhydric alcohol esters described in JP-A-2009-286931 are also preferable.

  These plasticizers may be used alone or in admixture of two or more. The amount of the plasticizer added can generally be 2 to 120 parts by weight, preferably 2 to 70 parts by weight, and more preferably 2 to 30 parts by weight with respect to 100 parts by weight of the thermoplastic resin contained in each dope. In particular, 5 to 20 parts by mass is preferable. For example, when the dope used for forming the cellulose acylate layer used in the present invention is dope (A) and the dope used for forming the acrylic layer is dope (B), the dope used for forming the adjacent layer is It is preferable to use a common plasticizer from the viewpoint of less occurrence of disturbance at the dope interface during casting, better adhesion at the interface, and curl reduction.

<Ultraviolet absorber>
In the optical film A according to the present invention, an ultraviolet absorber is preferably used from the viewpoint of preventing deterioration due to light or the like of a polarizing plate or a liquid crystal cell.

  As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Specific examples of the ultraviolet absorber preferably used in the present invention include, for example, hindered phenol compounds, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salts Compound etc. are mentioned. The addition amount of these ultraviolet light inhibitors is preferably in the range of 1 ppm to 1.0% by mass ratio, more preferably in the range of 10 to 1000 ppm, with respect to the polyester resin or acrylic resin.

  Specific examples of UV absorbers include UV-1 to UV-3 shown below, but UV absorbers applicable to the present invention are not limited to these.

<Peeling accelerator>
The optical film according to the present invention preferably contains 0.01% by mass to 20% by mass of an organic acid that satisfies the following requirements (1) to (3) with respect to the resin.
(1) Includes a structure in which a polyhydric alcohol and a polycarboxylic acid are bonded by forming an ester bond. (2) The total number of molecules of the polyhydric alcohol and polycarboxylic acid forming the compound is 3 or more.
(3) It has at least one unsubstituted carboxy group derived from a polyvalent carboxylic acid.

  In the organic acid satisfying the above requirements (1) to (3), it is possible to improve the peelability from the solution film-forming equipment (the metal support when the dope is fluent) by the unsubstituted carboxy group. Then, an organic acid satisfying the requirements (1) to (3) can be used as a peeling accelerator.

  Further, the unsubstituted carboxy group adheres to the metal surface of the support, and the polyhydric alcohol part or the hydrophobic group part substituted by the polyvalent alcohol part blocks the metal surface of the support from an oxidizing agent such as oxygen. Compared to organic acids that do not contain a monohydric alcohol moiety or a hydrophobic group moiety substituted therefor, corrosion of the metal can be prevented.

  Hereinafter, the organic acid that satisfies the requirements (1) to (3) that can be used as a peeling accelerator and other peeling accelerators that may be used in combination will be described.

  Although it does not specifically limit as polyvalent carboxylic acid used for the organic acid which satisfy | fills the requirements of said (1)-(3), For example, a succinic acid, a citric acid, tartaric acid, diacetyl tartaric acid, malic acid, and adipic acid are preferable.

  In the organic acid satisfying the requirements (1) to (3), the number of polyvalent carboxylic acid molecules is preferably 1 to 20, more preferably 1 to 15, and more preferably 1 to 10. Particularly preferred.

  Examples of the polyhydric alcohol used in the organic acid that satisfies the requirements (1) to (3) include adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, , 3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3- Examples thereof include methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol, and glycerin. Among these, glycerin is preferable.

  Among the organic acids that satisfy the requirements (1) to (3), the number of polyhydric alcohol molecules is preferably 1 to 20, more preferably 1 to 15, and particularly preferably 1 to 10. preferable.

  In addition to the polyhydric alcohol and polyvalent carboxylic acid that constitute the organic acid, the organic acid that satisfies the requirements (1) to (3) is a monovalent acid having a substituent having 4 or more carbon atoms. It may have a structure in which an ester bond is formed with a part of the hydroxy group of the polyhydric alcohol. Specific examples of the monovalent acid having a substituent having 4 or more carbon atoms are given below. The substituent in the monovalent acid having a substituent having 4 or more carbon atoms means R when the monovalent acid having a substituent having 4 or more carbon atoms is represented as RCOOH.

"fatty acid"
Caproic acid, heptylic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, ricinolenic acid, undecanoic acid.

《Alkyl sulfate》
Myristyl sulfate, cetyl sulfate, oleyl sulfate.

《Alkylbenzene sulfonic acid》
Dodecylbenzenesulfonic acid, pentadecylbenzenesulfonic acid.

《Alkyl naphthalene sulfonic acid》
Sesquibutyl naphthalene sulfonic acid, diisobutyl naphthalene sulfonic acid.

  Among these, a monovalent acid having a substituent having 4 or more carbon atoms, which is a fatty acid, is preferable, caprylic acid, lauric acid, stearic acid, and oleic acid are more preferable, and oleic acid is particularly preferable.

  In the organic acid satisfying the requirements (1) to (3), the number of molecules of the monovalent acid having a substituent having 4 or more carbon atoms is preferably 0 to 4, and preferably 0 to 3. More preferred is 0-2.

  In the organic acid satisfying the requirements (1) to (3), the total number of molecules of the polyhydric alcohol and the polycarboxylic acid forming the compound is 3 or more, preferably 3 to 30. More preferably, it is ~ 20.

  In the organic acid satisfying the above requirements (1) to (3), the ratio of the polyvalent carboxylic acid, the polyhydric alcohol, and the monovalent acid having a substituent having 4 or more carbon atoms is not particularly limited. Two or more unsubstituted hydroxyl groups may remain, or an unsubstituted hydroxyl group may remain.

  The organic acid that satisfies the requirements (1) to (3) has at least one unsubstituted carboxy group derived from a polyvalent carboxylic acid, and has 1 to 40 unsubstituted carboxy groups derived from the polyvalent carboxylic acid. It is preferable to have 1-30.

  The organic acid satisfying the requirements (1) to (3) may be used alone or as a mixture. In addition, the organic acid satisfying the requirements (1) to (3) may be ionized depending on the case, and may form a salt with any metal ion depending on the case.

  Examples of preferred organic acid compounds that satisfy the requirements (1) to (3) used in the present invention are shown below.

  Organic acids (partial condensates of organic acids) having the following composition are preferred.

  The addition amount of the organic acid satisfying the requirements (1) to (3) contained in the optical film according to the present invention is a ratio of 0.01 to 20% by mass with respect to the resin, and is 0.05 to 10%. It is particularly preferable that the content is mass%, and it is more preferable that the content is 0.1 to 5 mass%. In addition, when the organic acid which satisfy | fills the requirements of said (1)-(3) is a mixture as for the addition amount of the organic acid which satisfy | fills the requirements of said (1)-(3), all said (1)-( It means the total amount of organic acid that satisfies the requirement 3).

  When the addition amount is 0.001% or more, the polarizer durability improving effect and the peelability improving effect are sufficient. An addition amount of 20% by mass or less is preferable because the organic acid hardly bleeds out at a high temperature and high humidity, and the orthogonal transmittance of the polarizing plate hardly increases.

  In addition, even if the addition amount is 0.01% or less, the releasability can be achieved even with an addition amount of about 0.001 to 0.01% by combining with a peelability improving technique such as cooling of the peeling part of the casting support. Improvement can be expected.

<Matting agent>
To the optical film A according to the present invention, fine particles are generally added from the viewpoint of imparting scratch resistance and smooth transportability when handled. They are generally called matting agents, anti-blocking agents or anti-scratching agents and are conventionally used. They are not particularly limited as long as they exhibit the above-mentioned functions, and the matting agent may be an inorganic matting agent composed of an inorganic compound or an organic matting agent composed of an organic compound. Good.

  Preferred examples of the inorganic matting agent composed of an inorganic compound include inorganic compounds containing silicon (for example, silicon dioxide, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, etc.), titanium oxide, Preferred are zinc oxide, aluminum oxide, barium oxide, zirconium oxide, strontium oxide, antimony oxide, tin oxide, tin oxide / antimony, calcium carbonate, talc, clay, calcined kaolin and calcium phosphate, and more preferably inorganic compounds containing silicon. Although it is zirconium oxide, silicon dioxide is particularly preferably used from the viewpoint of reducing the turbidity (also referred to as haze) of the optical film. As the silicon dioxide fine particles, for example, commercially available products having trade names such as Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above, manufactured by Nippon Aerosil Co., Ltd.) can be used. As the fine particles of zirconium oxide, for example, those commercially available under trade names such as Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) can be used.

  Moreover, as a preferable specific example of the organic matting agent comprised from the said organic compound, the fine particle comprised from polymers, such as a silicone resin, a fluororesin, and an acrylic resin, for example is preferable, Especially, the fine particle comprised from a silicone resin Is preferably used. Among silicone resins, those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, Tospearl 105, Tospearl 108, Tospearl 120, Tospearl 145, Tospearl 3120, and Tospearl 240 (above, manufactured by Toshiba Silicone Co., Ltd.) ) Etc. can be used.

  When these matting agents are added to a resin solution or the like, the method is not particularly limited, and any method can be used as long as a desired resin solution can be prepared. For example, the matting agent may be contained in the step of mixing the resin and the solvent, or the matting agent may be added after preparing the mixed solution with the resin and the solvent. Furthermore, the dope containing the resin may be added and mixed immediately before casting, which is a so-called immediately preceding addition method, and the mixing is used by installing a screw-type kneading member online. Specifically, a static mixer such as an inline mixer is preferable, and as the inline mixer, for example, a static mixer SWJ (Toray static in-pipe mixer Hi-Mixer, manufactured by Toray Engineering Co., Ltd.) Is preferred.

  When the optical film according to the present invention is a laminated film composed of a core layer and a skin layer, the fact that the layer located in at least one of the outermost layers contains a matting agent indicates that the film surface has a scratch resistance and a wide width due to a reduction in the coefficient of friction. From the viewpoint of prevention of creaking that occurs when a width film is wound in a long length, and prevention of film breakage, both surface layers preferably contain a matting agent, so that scratch resistance and creaking are effective. Particularly preferable from the viewpoint of reduction.

  In the optical film according to the present invention, if the matting agent is not added in a large amount, the haze of the film does not increase, and when it is actually used in an LCD (Liquid Crystal Display liquid crystal display), the contrast is lowered and the bright spot is reduced. Inconvenience such as occurrence is less likely to occur. If the amount is too small, the above-mentioned creaking and scratch resistance can be realized. From these viewpoints, it is preferably included at a ratio of 0.01 to 5.0 mass%, more preferably included at a ratio of 0.03 to 3.0 mass%, and a ratio of 0.05 to 1.0 mass% It is particularly preferable to include

<< Optical film manufacturing method >>
The optical film A and the optical film B can be manufactured by a solution casting method or a melt casting method. The solution casting method is preferable from the viewpoint of suppressing optical defects such as coloring of the optical film, foreign matter defects, and die lines, and the melt casting method is preferable from the viewpoint of suppressing the solvent from remaining in the optical film.

A) Solution casting method A method for producing an optical film containing cellulose acylate by the solution casting method is, for example, A1) Dope by dissolving at least cellulose acylate and, if necessary, other additives in a solvent. A2) a step of casting a dope on an endless metal support, A3) a step of evaporating a solvent from the cast dope to form a web, A4) a step of peeling the web from the metal support, A5) After drying the web, it may include a step of drawing to obtain a film.

A1) Dope preparation step In a dissolution vessel, a dope is prepared by dissolving a resin and, if necessary, other additives in a solvent.

  A solvent can be used without a restriction | limiting, if a resin, another additive, etc. are melt | dissolved.

  The concentration of the resin in the dope is preferably high in order to reduce the drying load. However, if the concentration of the resin is too high, it is difficult to filter. Therefore, the concentration of the resin in the dope is preferably in the range of 10 to 35% by mass, and more preferably in the range of 15 to 25% by mass.

  The method of dissolving the resin in the solvent can be, for example, a method of dissolving under heating and pressure. A higher heating temperature is preferable from the viewpoint of increasing the solubility of cellulose acylate. If the temperature is too high, the pressure needs to be increased, and the productivity is lowered. Therefore, the heating temperature is preferably within the range of 45 to 120 ° C.

  The additive may be added batchwise to the dope, or an additive solution may be separately prepared and added inline. In particular, it is preferable that all or part of the fine particles be added in-line in order to reduce the load on the filter medium.

  For in-line addition and mixing, for example, a static mixer (manufactured by Toray Engineering), an in-line mixer such as SWJ (Toray Static In-Pipe Mixer Hi-Mixer), or the like is preferably used.

  The obtained dope may contain insoluble matters such as impurities contained in a resin as a raw material, for example. Such an insoluble matter can become a bright spot foreign material in the obtained film. In order to remove insoluble matter, it is preferable to further filter the obtained dope.

A2) Casting step The dope is cast on the endless metal support from the slit of the pressure die.

  As the metal support, a stainless steel belt or a drum whose surface is plated with a casting is preferably used. The surface of the metal support is preferably mirror-finished.

  The width of the cast can be in the range of 1-4 m. The surface temperature of the metal support in the casting process is set to −50 ° C. or higher and below the temperature at which the solvent boils and does not foam. A higher temperature is preferable because the web can be dried at a higher speed, but it is within a temperature range in which foaming of the web and deterioration of flatness can be prevented.

  The surface temperature of the metal support is preferably in the range of 0 to 100 ° C, more preferably in the range of 5 to 30 ° C. Alternatively, the metal support may be cooled so that the web is gelled and can be peeled off from the drum in a state containing a large amount of residual solvent.

  The method for adjusting the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of bringing hot water into contact 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 using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming . In particular, it is preferable to efficiently dry by changing the temperature of the metal support and the temperature of the drying air during the period from casting to peeling.

A3) Solvent evaporation step The web (dope film obtained by casting the dope on the metal support) is heated on the metal support to evaporate the solvent. The drying method and drying conditions of the web can be the same as in the above-described A2) casting step.

A4) Peeling Step The web obtained by evaporating the solvent on the metal support is peeled off at the peeling position on the metal support.

  The residual solvent amount of the web at the time of peeling at the peeling position on the metal support is preferably within the range of 10 to 150% by mass in order to improve the flatness of the obtained film. % Or in the range of 60 to 130 mass%, more preferably in the range of 20 to 30 mass% or 70 to 120 mass%.

  The amount of residual solvent in the web is defined by the following formula.

Residual solvent amount (%) = (mass before web heat treatment−mass after web heat treatment) / (mass after web heat treatment) × 100
Note that the heat treatment for measuring the residual solvent amount means a heat treatment at 115 ° C. for 1 hour.

A5) Drying and stretching step The web obtained by peeling from the metal support is dried as necessary and then stretched. The web may be dried while being conveyed by a large number of rollers arranged above and below, or may be dried while being conveyed while fixing both ends of the web with clips.

  The method of drying the web may be a method of drying with hot air, infrared rays, a heating roller, microwaves, or the like, and a method of drying with hot air is preferable because it is simple.

  An optical film having a desired retardation is obtained by stretching the web. The retardation of the optical compensation film can be controlled by adjusting the magnitude of tension on the web.

  The web is stretched in either the web width direction (TD direction) or the transport direction (MD direction).

  The web may be stretched uniaxially or biaxially. Biaxial stretching may be sequential biaxial stretching or simultaneous biaxial stretching.

  Although the draw ratio depends on the thickness of the obtained optical film and the required retardation, for example, the draw ratio in the biaxial direction perpendicular to each other is finally 0.8 to 1 in the casting direction. Within a range of 5 times, preferably within a range of 1.1 to 2.5 times in the width direction, within a range of 0.8 to 1.0 times in the casting direction, and 1.2 to in the width direction It is more preferable to be within the range of 2.0 times.

  In addition, a draw ratio is represented by the value W / W0 of the ratio of the length of the film in the drawing direction before and after drawing (W is after drawing and W0 is the length before drawing). A draw ratio of 1.0 indicates that the film is not drawn.

  The stretching temperature is preferably in the range of 120 to 230 ° C, more preferably in the range of 130 to 220 ° C, and even more preferably in the range of greater than 130 ° C and 210 ° C or less.

  The stretching method of the web is not particularly limited, and a method of making a difference in circumferential speed between a plurality of rollers and stretching in the casting direction (conveying direction) using the circumferential speed difference (roller stretching method), both ends of the web Fix with clips and pins, widen the gap between clips and pins in the casting direction and stretch in the casting direction, spread in the width direction and stretch in the width direction, both in the casting direction and in the width direction It may be a method of expanding and stretching in both the casting direction and the width direction (tenter stretching method).

  The residual solvent of the web at the start of stretching is preferably 20% by mass or less, more preferably 15% by mass or less.

  The stretched film is dried as necessary and then wound. As described above, the film may be dried while being transported by a large number of rollers arranged on the top and bottom (roller method), or may be dried while being transported while fixing both ends of the web with clips. (Tenter method).

B) Melt casting method The method of producing by the melt casting method is as follows: B1) Step of producing molten pellets (pelletizing step), B2) Step of extruding after melting and kneading the molten pellets (melt extrusion step), B3) A step of cooling and solidifying the molten resin to obtain a web (cooling and solidifying step), and B4) a step of stretching the web (stretching step).

B1) Pelletization process It is preferable that the resin composition containing the thermoplastic resin as the main component of the optical film is previously kneaded and pelletized. The pelletization can be performed by a known method. For example, a resin composition containing the above-described thermoplastic resin and, if necessary, an additive such as a plasticizer is melt-kneaded in an extruder, and then die-molded. Extruded into strands. The molten resin extruded in a strand form can be cooled with water or air, and then cut to obtain pellets.

  The pellet raw material is preferably dried before being fed to the extruder in order to prevent decomposition.

  The mixture of the antioxidant and the thermoplastic resin may be mixed with each other, may be mixed by impregnating the thermoplastic resin with an antioxidant dissolved in a solvent, or the antioxidant may be thermoplastic. The resin may be sprayed and mixed. The atmosphere around the feeder portion of the extruder and the outlet portion of the die is preferably an atmosphere of dehumidified air or nitrogen gas in order to prevent deterioration of the raw material of the pellet.

  In an extruder, it is preferable to knead at a low shearing force or at a low temperature so as not to cause deterioration of the resin (decrease in molecular weight, coloring, gel formation, etc.). For example, when kneading with a twin-screw extruder, it is preferable to use a deep groove type screw so that the rotational directions of the two screws are the same. In order to knead uniformly, it is preferable that two screw shapes mesh with each other.

  An optical film may be produced by melt-kneading a thermoplastic resin that has not been melt-kneaded as a raw material in an extruder without pelletizing the resin composition containing the thermoplastic resin.

B2) Melt Extrusion Step The obtained molten pellets and other additives as necessary are supplied from the hopper to the extruder. The supply of pellets is preferably performed under vacuum, reduced pressure, or an inert gas atmosphere in order to prevent oxidative decomposition of the pellets. Then, in an extruder, melt pellets that are film materials and, if necessary, other additives are melt-kneaded.

  The melting temperature of the film material in the extruder is preferably in the range of Tg to (Tg + 100) ° C., more preferably when the glass transition temperature of the film is Tg (° C.), although it depends on the type of film material. Is within the range of (Tg + 10) to (Tg + 90) ° C.

  Furthermore, when additives such as plasticizers and fine particles are added in the middle of the extruder, a mixing device such as a static mixer is further arranged on the downstream side of the extruder to uniformly mix these components. May be.

  The molten resin extruded from the extruder is filtered through a leaf disk filter or the like as necessary, and further mixed with a static mixer or the like, and extruded from a die into a film.

  The extrusion flow rate is preferably stabilized using a gear pump. Moreover, it is preferable that the leaf disk filter used for removal of a foreign material is a stainless fiber sintered filter. The stainless steel fiber sintered filter is an integrated, intricately intertwined stainless steel fiber body that is compressed and sintered by integrating the contact points. The density is changed according to the thickness of the fiber and the amount of compression, and the filtration accuracy is adjusted. it can.

  The melting temperature of the resin at the exit portion of the die can be in the range of about 200-300 ° C.

B3) Cooling and solidifying step The resin extruded from the die is nipped between the cooling roller and the elastic touch roller to make the film-like molten resin a predetermined thickness. Then, the film-like molten resin is cooled and solidified stepwise by a plurality of cooling rollers.

  The surface temperature of the cooling roller can be Tg (° C.) or lower when the glass transition temperature of the obtained film is Tg (° C.). The surface temperatures of the plurality of cooling rollers may be different.

  The elastic touch roller is also called a pinching rotary body. A commercially available elastic touch roller can also be used. The film surface temperature on the elastic touch roller side can be in the range of Tg to (Tg + 110) ° C. of the film.

  The film-like molten resin solidified from the cooling roller is peeled off by a peeling roller or the like to obtain a web. When peeling the film-like molten resin, it is preferable to adjust the tension in order to prevent deformation of the obtained web.

B4) Stretching step The obtained web is stretched with a stretching machine to obtain a film. Stretching is performed either in the web width direction or in the transport direction.

  The stretching method, stretching ratio, and stretching temperature of the web can be the same as described above.

<Polarizing plate>
The optical film according to the present invention can be used in the polarizing plate of the present invention and the liquid crystal display device of the present invention using the polarizing plate. Since the optical film according to the present invention is a film that also functions as a polarizing plate protective film, it is not necessary to prepare an optical film having a phase difference separately from the polarizing plate protective film, so the thickness of the liquid crystal display device is reduced. The manufacturing process can be simplified.

  In the liquid crystal display device of the present invention, the polarizing plate according to the present invention is preferably bonded to both surfaces of the liquid crystal cell via an adhesive layer.

  The polarizing plate according to the present invention can be produced by a general method. The polarizer side of the optical film according to the present invention is subjected to alkali saponification treatment and bonded to at least one surface of a polarizer prepared by immersion and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. it can. Another polarizing plate protective film can be bonded to the other surface.

  Moreover, a polarizing plate protective film can also be bonded using an active energy ray-curable adhesive. In the present invention, it is preferable that the optical film A and the optical film B are bonded to the polarizer using an active energy ray-curable adhesive, respectively, because moisture permeability can be effectively controlled.

  The configuration of the liquid crystal display device will be specifically described below.

  FIG. 1 is a schematic diagram illustrating an example of a configuration of a liquid crystal display device. In the form shown in FIG. 1, the optical film B (105) and the polarizer 104 are preferably bonded via an active energy ray-curable adhesive 103B. Similarly, the optical film A (102) and the polarizer 104 are preferably bonded via an active energy ray-curable adhesive 103A. It is preferable to use an active energy ray-curable adhesive. However, in the present invention, not only the active energy ray-curable adhesive, but also curable adhesives such as urethane adhesives, epoxy adhesives, aqueous polymer-isocyanate adhesives, thermosetting acrylic adhesives, Use moisture-curing urethane adhesive, anaerobic adhesive such as polyether methacrylate, ester methacrylate, oxidized polyether methacrylate, cyanoacrylate instant adhesive, acrylate and peroxide two-component instant adhesive, etc. be able to. The adhesive may be a one-component type or a two-component type in which two or more components are mixed before use. The adhesive may be a solvent system using an organic solvent as a medium, or an aqueous system such as an emulsion type, a colloidal dispersion liquid type, or an aqueous solution type that is a medium containing water as a main component, or a solvent-free type. It may be a mold. The concentration of the adhesive liquid may be appropriately determined depending on the film thickness after bonding, the coating method, the coating conditions, and the like, and is usually 0.1 to 50% by mass.

(Active energy ray curable adhesive)
Preferable examples of the active energy ray-curable adhesive include, for example, (α) cationic polymerizable compound, (β) photocationic polymerization initiator, and (γ) as disclosed in Japanese Patent Application Laid-Open No. 2011-028234. Examples include an active energy ray-curable adhesive composition containing components of a photosensitizer that exhibits maximum absorption in light having a wavelength longer than 380 nm and (δ) a naphthalene photosensitizer. Of course, other active energy ray-curable adhesive compositions may be used.

  A polarizing plate can be manufactured by bonding the optical film of the present invention to one surface of a polarizer using an active energy ray-curable adhesive. When the adhesiveness is different between the two surfaces of the retardation film, it is preferable to bond them to the one having good adhesiveness.

  Hereinafter, an example of the manufacturing method of the polarizing plate using an active energy ray hardening adhesive is demonstrated.

  The polarizing plate includes an adhesive application step of forming an adhesive layer by applying the following active energy ray-curable adhesive to at least one of the adhesive surfaces of the polarizer and the retardation film, and the adhesive layer A bonding step in which the polarizer and the retardation film are bonded and bonded via the adhesive layer, and a curing step in which the adhesive layer is cured in a state where the polarizer and the retardation film are bonded via 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 easy adhesion treatment is treated as a bonding surface with a polarizer, so on both surfaces of the retardation film, on the surface to be bonded with the active energy ray-curable adhesive, Apply easy adhesion treatment. Examples of the easy adhesion treatment include corona treatment and plasma treatment.

(Adhesive application process)
In the adhesive application step, the active energy ray-curable adhesive is applied to at least one of the adhesive surfaces of the polarizer and the retardation film. When the active energy ray-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. Moreover, after casting an active energy ray hardening adhesive between a polarizer and a phase difference film, the method of pressing with a roller etc. and spreading uniformly can also be utilized.

(Bonding process)
After apply | coating an active energy ray hardening adhesive agent by said method, it processes by a bonding process. In this bonding step, for example, when an active energy ray-curable adhesive is applied to the surface of the polarizer in the previous application step, a retardation film is superimposed thereon. When the active energy ray-curable adhesive is applied to the surface of the retardation film in the previous application step, a polarizer is superimposed thereon. Moreover, when an active energy ray-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 bonded to both sides of a polarizer, and both sides use an active energy ray curable adhesive, the both sides of the polarizer are respectively attached via an active energy ray curable adhesive. A phase difference 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 curable adhesive is irradiated with active energy rays, and a cationic polymerizable compound (eg, epoxy compound or oxetane compound) or a radical polymerizable compound (eg, acrylate compound, acrylamide type). The active energy ray-curable adhesive containing the compound or the like is cured, and the polarizer and the retardation film, or the polarizer and the retardation film, which are superposed via the active energy ray-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. Moreover, when laminating a retardation film and a protective film on both sides of a polarizer, the active energy is in a state where the retardation film and the protective film are superimposed on both sides of the polarizer via an active energy ray-curable adhesive, respectively. It is advantageous to irradiate the line and simultaneously cure the active energy ray 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 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 target adhesiveness may not be obtained.

  In the polarizing plate obtained as described above, the thickness of the adhesive layer is not particularly limited, but is usually within a range of 0.01 to 10, and preferably within a range of 0.5 to 5 μm.

  In addition to the antiglare layer or the clear hard coat layer, the polarizing plate protective film used on the surface side of the display device preferably has an antireflection layer, an antistatic layer, an antifouling layer, and a backcoat layer.

  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.

  The polarizer is preferably prepared by forming a polyvinyl alcohol aqueous solution into a film and dyeing it by uniaxial stretching or dyeing and then uniaxially stretching and then performing a durability treatment with a boron compound. The film thickness of the polarizer is preferably in the range of 5 to 30 μm, and particularly preferably in the range of 10 to 20 μm.

<Liquid crystal display device>
The polarizing plate of the present invention is provided in a liquid crystal display device.

  FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a liquid crystal display device 100 in which the above-described polarizing plates 101A and 101B of the present invention are arranged on both surfaces of a liquid crystal cell 101C.

  In FIG. 1, a liquid crystal cell 101C is configured by sandwiching both surfaces of a liquid crystal layer 107 between glass substrates 108A and 108B as transparent substrates, and an adhesive layer 106 is formed on each surface of each glass substrate 108A and 108B. Accordingly, polarizing plates 101A and 101B having the configuration shown in FIG. 1 are arranged to constitute the liquid crystal display device 100.

  The liquid crystal cell 101C is configured by arranging an alignment film, a transparent electrode, and a glass substrate (glass base materials 108A and 108B) on both surfaces of a liquid crystal substance.

  By providing the liquid crystal display device with the polarizing plate of the present invention excellent in durability, flatness, etc., the glass substrate constituting the liquid crystal cell can be thinned, and as a result, the thinned liquid crystal is achieved. A display device can be obtained.

  Examples of the material constituting the glass base materials 108A and 108B that can be used for the liquid crystal cell 101C include soda lime glass and silicate glass, and is preferably silicate glass. Silica glass or borosilicate glass is more preferable.

  The glass constituting the glass base material is preferably a non-alkali glass that does not substantially contain an alkali component, specifically, a glass having an alkali component content of 1000 ppm or less. The content of the alkali component in the glass substrate is preferably 500 ppm or less, and more preferably 300 ppm or less. In a glass substrate containing an alkali component, substitution of cations occurs on the film surface, and soda blowing phenomenon tends to occur. Thereby, the density of the film surface layer tends to be lowered, and the glass substrate is easily damaged.

  The thicknesses of the glass substrates 108A and 108B of the liquid crystal cell constituting the liquid crystal display device are preferably within the range of the liquid crystal display 0.4 to 0.6 mm. Such a thickness is preferable in that it can contribute to the formation of a thin liquid crystal display device.

  The glass substrate can be formed by a known method such as a float method, a down draw method, an overflow down draw method or the like. Of these, the overflow downdraw method is preferred because the surface of the glass substrate does not come into contact with the molded member during molding and the surface of the resulting glass substrate is hardly damaged.

Moreover, such a glass base material can also be obtained as a commercial item, for example, non-alkali glass AN100 (thickness 500 μm) manufactured by Asahi Glass Co., Ltd., a glass substrate EAGLE XG (r) Slim (thickness manufactured by Corning) 300 μm, 400 μm, etc.), a glass substrate (thickness: 100 to 200 μm) manufactured by Nippon Electric Glass Co., Ltd., and the like.

  Further, the polarizing plates 101A and 101B as shown in FIG. 1 and the glass base materials 108A and 108B constituting the liquid crystal cell 101C are bonded via an adhesive layer 106.

  As the adhesive layer, a double-sided tape, for example, a 25 μm-thick double-sided tape manufactured by Lintec (baseless tape MO-3005C) or a composition used for forming the active energy ray-curable resin layer is applied. be able to.

  The bonding between the surface of the polarizing plate on the side of the retardation film and at least one surface of the liquid crystal cell can be performed by a known method. Depending on the case, it may be bonded through an adhesive layer.

  The mode (driving method) of the liquid crystal display device is not particularly limited, and liquid crystal display devices in various drive modes such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS, and OCB can be used. In particular, it is preferable to apply the present invention to a VA mode liquid crystal display device, so that the effects of the present invention can be exhibited.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

(Compounds used in Examples)
The compounds used in the following examples are shown below together with their abbreviations.
[Compound having the structure represented by the general formula (1)]
B1: Exemplary compound (1-2) having a structure represented by the general formula (1)
B2: Exemplary compound (1-1) having a structure represented by the general formula (1)
B3: Exemplary compound (1-3) of a compound having a structure represented by the general formula (1)

[Phase difference increasing agent]
N1: 9H-carbazole-9-ethanol N2: n-hexylcarbazole N3: 2,3-diphenylquinoxaline N4: 2-methylbenzoxazole N5: 2- (4-tert-butylphenyl) -5- (4-biphenyl) -1,3,4-oxadiazole

Note that N8 cyclohexane is substituted with trans at positions 1 and 4.
N11: Exemplary compound 1 of the compound having a structure represented by the general formula (3)
N12: Exemplary compound 6 having a structure represented by the general formula (3) 6
N13: Exemplary compound 176 having a structure represented by general formula (3)

[Plasticizer]
S1: Sugar ester: BzSc (benzyl saccharose: the following sugar residue is B-2 and the substituent is a mixture of a1 to a4 described below), average ester substitution degree = 5.5

Ｓ３〈重縮合エステル〉
重縮合エステルＳ３は以下のようにして調製した。

S3 <Polycondensed ester>
Polycondensation ester S3 was prepared as follows.

180 g of 1,2-propylene glycol, 103 g of phthalic anhydride, 244 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 slow cooling tube. The temperature is gradually raised with stirring until it reaches 200 ° 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 polycondensed ester S3. The acid value was 0.10 and the number average molecular weight was 320.
S4 <Polycondensed ester>
Polycondensation ester S4 was prepared as follows.

251 g of 1,2-propylene glycol, 103 g of phthalic anhydride, 244 g of adipic acid, 610 g of benzoic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst, 2 L four-neck equipped with a thermometer, stirrer, and quick cooling tube 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 polycondensed ester S4. The acid value was 0.10 and the number average molecular weight was 450.
S5 <Polycondensed ester>
Polycondensation ester S5 was prepared as follows.

  251 g of 1,2-propylene glycol, 354 g of terephthalic acid, 680 g of p-toluic 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 quick cooling tube. 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 under reduced pressure at 200 ° C. to obtain a polycondensed ester S5. The acid value was 0.30 and the number average molecular weight was 400.

For S6 to S8, the additives listed in Table 6 below were used.
S6: Additive A
S7: Additive B
S8: Additive C

Ｓ１１：トリフェニルホスフェート
Ｓ１２：ジフェニルビフェニルホスフェート

Ｓ１４：ジブチルフタレート
Ｓ１５：以下の組成（質量比）からなる有機酸（多価アルコールと多価カルボン酸に加え、炭素数が４以上の置換基を有する一価の酸が該多価アルコールの一部のヒドロキシル基とエステル結合を形成した構造）を用いた。In Table 6, EG represents ethylene glycol, PG represents propylene glycol, BG represents butylene glycol, TPA represents terephthalic acid, PA represents phthalic acid, AA represents adipic acid, and SA represents succinic acid. Yes.
S9: Trimethylolpropane tribenzoate

S11: Triphenyl phosphate S12: Diphenyl biphenyl phosphate

S14: Dibutyl phthalate S15: An organic acid having the following composition (mass ratio) (in addition to polyhydric alcohol and polycarboxylic acid, a monovalent acid having a substituent having 4 or more carbon atoms is one of the polyhydric alcohols). Part of the hydroxyl group and a structure in which an ester bond is formed).

Glycerin (2-3), citric acid (1-2), oleic acid (1-2)
[Example 1]
<< Production of Optical Film A >>
<< Production of Optical Film T1-1 >>
As the optical film T1-1, KC6UA manufactured by Konica Minolta, which is a commercially available protective film having a thickness of 60 μm, was used as it was.

<< Production of Optical Films T1-2, T1-4, and T1-6 >>
(Acrylic resin and acrylic elastic polymer particles)
As the acrylic resin, a copolymer having a mass ratio of methyl methacrylate / methyl acrylate of 96/4 was used. Further, as the elastic rubber particles, acrylic elastic polymer particles having a three-layer structure including an innermost layer, an intermediate layer, and an outermost layer were used. In the acrylic elastic polymer particles, the innermost layer is a hard polymer obtained by polymerizing methyl methacrylate with a small amount of allyl methacrylate, the intermediate layer is mainly composed of butyl acrylate, styrene and a small amount of Soft elastic body polymerized using allyl methacrylate, outermost layer is made of a hard polymer polymerized with a small amount of ethyl acrylate in methyl methacrylate, and the average particle size up to the elastic body that is the intermediate layer The diameter is 240 nm.

(Production of acrylic resin film)
Pellets in which the above acrylic resin and the above acrylic elastic polymer particles were blended at a mass ratio of the former / the latter = 70/30 were melt-kneaded with a twin screw extruder to obtain an acrylic resin composition pellet. The pellets were put into a 65 mmφ single screw extruder, extruded through a T die having a set temperature of 275 ° C., and both sides of the extruded film-like molten resin were polished rolls (cooling rolls) having mirror surfaces set at 45 ° C. And an optical film T1-2 made of an acrylic resin having a thickness of 30 μm. The roll is sandwiched between a metal elastic roll (elastic roll) having a high elastic modulus whose surface is made of a metal material and filled with a fluid. Produced.

  Similarly to the optical film T1-2, the amount of extrusion through the T-type die was adjusted to produce an optical film T1-4 having a thickness of 60 μm and an optical film T1-6 having a thickness of 80 μm, respectively.

<< Production of Optical Film T1-3 >>
(Production of (meth) acrylic resin film)
[In the following formula, R ¹ represents a hydrogen atom, R ² and R ³ represent a methyl group, and a (meth) acrylic resin having a lactone ring structure {composition monomer mass ratio = methyl methacrylate / 2- (hydroxymethyl) acrylic Methyl acid = 8/2, lactone cyclization rate about 100%, lactone ring structure content 19.4%, weight average molecular weight 133000, melt flow rate 6.5 g / 10 min (240 ° C., 10 kgf), Tg 131 ° C.} Pellets of 90 parts by mass and a mixture of 10 parts by mass of acrylonitrile-styrene (AS) resin {Toyo AS AS20, manufactured by Toyo Styrene Co., Ltd .; Tg 127 ° C] are fed into a biaxial extruder and formed into a sheet at about 280 ° C. It was melt extruded to obtain a (meth) acrylic resin sheet having a lactone ring structure having a thickness of 110 μm. This unstretched sheet was stretched 2.0 times in length and 2.4 times in width under a temperature condition of 160 ° C., and a (meth) acrylic resin film (thickness: 40 μm, in-plane retardation value Ro: 0.8 nm) , Thickness direction retardation value Rt: 1.5 nm).

(Corona discharge treatment)
One side of the (meth) acrylic resin film obtained above was subjected to corona discharge treatment (corona discharge electron irradiation amount: 77 W / m ² / min).

  Polyester urethane (Daiichi Kogyo Seiyaku, trade name: Superflex 210, solid content: 33%) 16.8 g, cross-linking agent (oxazoline-containing polymer, product of Nippon Shokubai, trade name: Epocross WS-700, solid content: 25% ) 4.2 g, 2.0 g of 1% by mass ammonia water, 0.42 g of colloidal silica (manufactured by Fuso Chemical Industries, Quattron PL-3, solid content: 20% by mass) and 76.6 g of pure water were mixed to facilitate adhesion. An agent composition was obtained.

  The obtained easy-adhesive composition was applied to the corona discharge-treated surface of the (meth) acrylic resin film subjected to corona discharge treatment with a bar coater (# 6) so that the thickness after drying was 350 nm. . Then, the (meth) acrylic resin film is put into a hot air dryer (140 ° C.), and the easy-adhesive composition is dried for about 5 minutes to form an easy-adhesion layer (0.3 to 0.5 μm). Film T1-3 was produced.

<< Production of Optical Films T1-5 and T1-7 to T1-9 >>
(Production Example 1-Polyester A)
When the temperature of the esterification reactor was raised to 200 ° C., 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were charged and 0.017 parts by mass of antimony trioxide as a catalyst while stirring. 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine were charged. Next, the pressure was raised and the pressure esterification reaction was carried out under conditions of a gauge pressure of 0.34 MPa and 240 ° C., and then the esterification reaction vessel was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Furthermore, it heated up to 260 degreeC over 15 minutes, and 0.012 mass part of trimethyl phosphate was added. Then, after 15 minutes, dispersion treatment was performed with a high-pressure disperser, and after 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can and subjected to polycondensation reaction at 280 ° C. under reduced pressure.

After completion of the polycondensation reaction, it is filtered through a NASRON filter with a 95% cut diameter of 5 μm, extruded into a strand from a nozzle, and cooled and solidified using cooling water that has been filtered (pore diameter: 1 μm or less) in advance. And cut into pellets. The obtained polyethylene terephthalate resin (A) had an intrinsic viscosity of 0.62 dl / g and contained substantially no inert particles and internally precipitated particles. (Hereafter, abbreviated as PET (A).)
(Production Example 2-Polyester B)
Next, 10 parts by weight of a dried UV absorber (2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinon-4-one), PET (A) containing no particles 90 parts by mass (inherent viscosity is 0.62 dl / g) was mixed, and a polyethylene terephthalate resin (B) containing an ultraviolet absorber was obtained using a kneading extruder (hereinafter abbreviated as PET (B)).

(Production Example 3-Preparation of Adhesive Modified Coating Solution)
A transesterification reaction and a polycondensation reaction are performed by a conventional method, and as a dicarboxylic acid component (based on the whole dicarboxylic acid component) 46 mol% terephthalic acid, 46 mol% isophthalic acid, and 8 mol% sodium 5-sulfonatoisophthalate, A water-dispersible sulfonic acid metal group-containing copolymer polyester resin having a composition of 50 mol% ethylene glycol and 50 mol% neopentyl glycol (relative to the entire glycol component) was prepared as a glycol component. Next, 51.4 parts by mass of water, 38 parts by mass of isopropyl alcohol, 5 parts by mass of n-butyl cellosolve, 0.06 parts by mass of nonionic surfactant were mixed and then heated and stirred. After adding 5 parts by mass of a water-dispersible sulfonic acid metal base-containing copolymer polyester resin and continuing to stir until the resin is no longer agglomerated, the resin water dispersion is cooled to room temperature to obtain a solid content concentration of 5.0% by mass. A uniform water-dispersible copolymerized polyester resin liquid was obtained. Furthermore, after dispersing 3 parts by mass of aggregated silica particles (manufactured by Fuji Silysia Co., Ltd., Silicia 310) in 50 parts by mass of water, 99.46 parts by mass of the water-dispersible copolymerized polyester resin liquid was mixed with water of Silicia 310. 0.54 parts by mass of the dispersion was added, and 20 parts by mass of water was added with stirring to obtain an adhesive modified coating solution.

(Preparation of optical film T1-5)
After drying 90 parts by mass of PET (A) resin pellets containing no particles as a raw material for the base film intermediate layer and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber at 135 ° C. for 6 hours under reduced pressure (1 Torr) , And supplied to the extruder 2 (for the intermediate layer II layer), and PET (A) was dried by a conventional method and supplied to the extruder 1 (for the outer layer I layer and the outer layer III), respectively, and dissolved at 285 ° C. . After filtering these two kinds of polymers with a filter medium made of a sintered stainless steel (nominal filtration accuracy of 10 μm particles 95% cut), laminating them in a two-kind / three-layer confluence block, and extruding them into a sheet form from a die, The film was wound around a casting drum having a surface temperature of 30 ° C. using an electrostatic application casting method, and then cooled and solidified to produce an unstretched film. At this time, the discharge amount of each extruder was adjusted so that the ratio of the thicknesses of the I layer, the II layer, and the III layer was 10:80:10.

Next, after applying the above-mentioned adhesiveness-modified coating solution on the both sides of this unstretched PET film by a reverse roll method so that the coating amount after drying becomes 0.096 g / m ² , the coating was dried at 80 ° C. for 20 seconds. .

  The unstretched film on which this coating layer was formed was guided to a tenter stretching machine, and the film was guided to a hot air zone at a temperature of 125 ° C. while being gripped by a clip, and stretched 4.0 times in the width direction. Next, while maintaining the width stretched in the width direction, the film is processed at a temperature of 225 ° C. for 30 seconds, and further subjected to a relaxation treatment of 3% in the width direction, and is an uniaxially oriented PET film having a film thickness of 60 μm. T1-5 was obtained.

  In the production of T1-5, the thickness of the unstretched film was changed so that the thickness was changed from 60 μm to 80 μm, 100 μm, and 110 μm, respectively, in the same manner as T1-5, T1-7, T1-8, and T1 -9 was obtained.

<< Optical film T1-10 >>
(Production of cyclic olefin resin film (COP))
ZEONOR (manufactured by Nippon Zeon Co., Ltd.) was used as a retardation film made of a cyclic olefin (COP) resin.

<< Water vapor transmission rate of optical films T1-1 to T1-10 >>
The evaluation of the moisture permeability of the optical films T1-1 to T1-10 was performed by measuring the water vapor permeability at 40 ° C. and 90% RH by a method based on JIS K 7129 (1992).

  Table 7 shows the respective film thicknesses and water vapor transmission rates of the optical films T1-1 to T1-10.

<< Preparation of optical film B >>
<< Production of Retardation Film T2-1 >>
<Fine particle dispersion 1>
Fine particles (Aerosil R812 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.

<Fine particle addition liquid 1>
The fine particle dispersion 1 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 through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 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 acetate having an acetyl group substitution degree of 2.60 was added to a pressure dissolution tank containing a solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope was prepared by filtration using 244.

<Composition of main dope>
Methylene chloride 365 parts by mass Ethanol 50 parts by mass Cellulose acylate (C5) 100 parts by mass Particulate additive solution 1 1 part by mass The above was put into the sealed main dissolution vessel 1 and dissolved while stirring to prepare a dope.

  On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film was 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m. The peeled retardation film was stretched 30% in the width direction using a tenter while applying heat at 150 ° C. (stretching ratio: 1.3). The residual solvent at the start of stretching was 15%.

  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 retardation film T2-1 having a dry film thickness of 40 μm was obtained.

  In addition, C5 of Table 8 was used for the cellulose acylate resin.

<< Production of Retardation Films T2-2 to T2-7 >>
In the retardation film T2-1, as shown in Table 9, 5 parts by mass of the compound having the structure represented by the general formula (1) is added to 100 parts by mass of the cellulose acylate resin, as shown in Table 9. After that, retardation films T2-2 to T2-7 were produced in the same manner as the retardation film T2-1.

<< Evaluation of Retardation Films T2-1 to T2-7 >>
About each of retardation film T2-1 to T2-7 which is the obtained optical film B, the retardation value was measured with the following method.

<Measurement of retardation values Ro and Rt>
A 35 mm × 35 mm sample was cut out from the obtained retardation film, conditioned at 23 ° C. and 55% RH for 2 hours, and then in the vertical direction at an optical wavelength of 590 nm with an automatic birefringence meter (KOBRA-WR, Oji Scientific Co., Ltd.). And the extrapolated value of the retardation value measured in the same manner while tilting the film surface.

Formula _{(i) Ro = (n x} -n y) × d
Formula (ii) Rt = {(n _x + n _y ) / 2−n _z } × d
(Wherein, n _x is a refractive index in a slow axis direction in the film plane, n _y is a refractive index in a fast axis direction in the film plane, n _z is a refractive index in the thickness direction of the film And d is the thickness (nm) of the film.)
The retardation values Ro and Rt were measured at a wavelength of 590 nm under an environment of a temperature of 23 ° C. and a humidity of 55% RH using KOBRA-21ADH (manufactured by Oji Scientific Instruments).

<< Production of Polarizing Plate 1 >>
(Preparation of polarizer)
A polyvinyl alcohol film having a thickness of 50 μm was swollen with water at 35 ° C. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and further immersed in an aqueous solution at 45 ° C. consisting of 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water. . The obtained film was uniaxially stretched under conditions of a stretching temperature of 55 ° C. and a stretching ratio of 5 times. This uniaxially stretched film was washed with water and dried to obtain a polarizer 1 having a thickness of 10 μm.

(Preparation of coating solution 1 for forming an adhesive layer)
According to the following method, a coating liquid 1 for forming an adhesive layer, which is a cationic polymerization type active energy ray-curable adhesive liquid, was prepared.

  After the following components were mixed, defoaming was performed to prepare a coating solution 1 for forming an adhesive layer. Triarylsulfonium hexafluorophosphate was blended as a 50% propylene carbonate solution, and the solid content of triarylsulfonium hexafluorophosphate was shown below.

3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 45 parts by mass Epolide GT-301 (alicyclic epoxy resin manufactured by Daicel Chemical Industries)
40 parts by mass 1,4-butanediol diglycidyl ether 15 parts by mass Triarylsulfonium hexafluorophosphate
2.3 parts by mass 9,10-dibutoxyanthracene 0.1 parts by mass 1,4-diethoxynaphthalene 2.0 parts by mass (Preparation of polarizing plate)
First, T2-1 was used as the optical film B, and the surface was subjected to corona discharge treatment. The corona discharge treatment was performed at a corona output intensity of 2.0 kW and a line speed of 18 m / min. Next, the above-prepared coating solution 1 for forming an adhesive layer is applied to the T2-1 corona discharge-treated surface with a bar coater so that the film thickness after curing is about 3 μm, and the active energy ray curable resin layer is applied. (Also referred to as an adhesive layer). The prepared polyvinyl alcohol-iodine polarizer was bonded to the obtained active energy ray-curable resin layer.

  Subsequently, the optical film T1-8 produced above was used as the optical film A, and the surface thereof was subjected to corona discharge treatment. The conditions of the corona discharge treatment were a corona output intensity of 2.0 kW and a speed of 18 m / min. Next, the prepared coating solution 1 for forming an adhesive layer is applied to the corona discharge-treated surface of the optical film T1-8 with a bar coater so that the film thickness after curing is about 3 μm. A resin layer was formed.

  A polarizer bonded to one surface of the optical film T2-1 is bonded to the active energy ray curable resin layer, and the optical film T1-8 / active energy ray curable resin layer / polarizer / active energy ray is bonded. A laminate in which the curable resin layer / optical film T2-1 was laminated was obtained. In that case, it bonded so that the slow axis of optical film T2-1 and the absorption axis of a polarizer might mutually orthogonally cross.

From the optical film T2-1 surface side of this laminate, using an ultraviolet irradiation device with a belt conveyor (the lamp uses a D bulb manufactured by Fusion UV Systems), the ultraviolet light is adjusted so that the integrated light quantity becomes 750 mJ / cm ^2. , The active energy ray-curable resin layer was cured, and the polarizing plate 1 was produced. An adhesive layer forming method using the adhesive layer forming coating solution 1 is referred to as “UV adhesion 1”.

<< Production of Polarizing Plates 2-7 >>
In the production of the polarizing plate 1, the retardation film T2-1 was replaced with the retardation films T2-2 to T2-7, and polarizing plates 2 to 7 were produced in the same manner as the production of the polarizing plate 1.

<< Production of liquid crystal display devices 1 to 7 >>
The polarizing plates on both sides of the commercially available VA type liquid crystal display device (SONY 40 type display KLV-40J3000) were peeled off in advance, and the produced polarizing plates 1 to 7 were respectively applied to both sides of the glass surface of the liquid crystal cell. , Pasted.

  At that time, the direction of bonding of the polarizing plate is such that the surfaces of the retardation films T2-1 to T2-7 are on the liquid crystal cell side and in the same direction as the polarizing plate that has been bonded in advance. Liquid crystal display devices 1 to 7 corresponding to the polarizing plates 1 to 7 were produced, respectively, so that the absorption axis was directed.

<Evaluation of liquid crystal display device>
About each produced said liquid crystal display device, each evaluation of a color nonuniformity and a point-like defect was performed.

(Evaluation of moisture resistance: Evaluation of color unevenness due to fluctuations in water content)
The liquid crystal display device produced above was laid and placed on a stand or the like, and Bencot (registered trademark, manufactured by Asahi Kasei Fibers) was placed on a part of the polarizing plate for evaluation to contain water. The bencott was covered with 100 μm PET so that it would not dry, a black display signal was input to the TV from the PC, and the TV was turned on for 24 hours (the room temperature was set to 23 ° C., and the panel temperature was 38 ° C.). After 24 hours, remove the becot. The L ^* (brightness) of the portion where there was a becot was measured by EZ contrast (manufactured by ELDIM) as the L ^* of the water immersion portion. It was measured with EZ Contrast Bencot of the free portion of the L ^* a non-submerged portion L ^*. The measurement with EZ contrast was performed in the color mode with the TV displayed in black. The conditions for water immersion were such that the panel was turned on and was allowed to stand for 24 hours in a state where a bencott sufficiently soaked in water was attached. Subsequently, the value of the ratio L ^* of the water-immersed part / L ^{* of the} non-immersed part was calculated, and color unevenness was evaluated according to the following criteria.

A: 1.05 or more and 1.30 or less: No occurrence of color unevenness is observed at all. ○: More than 1.30 and 1.55 or less: Very slight weak color unevenness is observed, but there is no problem in practical use. △: More than 1.55 and less than 1.80: Color unevenness is slightly observed, but it is a level with no problem in practical use. ×: More than 1.80: Strong color unevenness occurs, and there is a problem in moisture resistance. In addition, when the value of the ratio of L ^* of the water-immersed part / L ^{* of the} non-immersed part was 1.05 or more, there was no sample in which point-like defects were observed, but the ratio value was 1. Since the case of less than 05 includes the case where a point-like defect occurs, the evaluation of color unevenness was confirmed by visual evaluation.

(Evaluation of point defects)
The film is bonded to the polarizing plate. This was incorporated into a liquid crystal display device, and the light and darkness appearing in a dot or plane shape when black display was observed visually and ranked according to the following criteria.
Rank Criteria A: Uniform dark field with no light omission ○: Slightly light and dark is partially recognized ○ △: Slightly light and dark is partially recognized △: Slightly dark and dark is recognized overall However, it is a level with no problem in practical use. X: Brightness and darkness are recognized as a whole. In addition, it is difficult to achieve both conventional color unevenness and point-like defects, and the ranks of both color unevenness and point-like defects are more than Δ in the above evaluation. If so, it can be put to practical use.

  The above evaluation results are shown in Table 9.

  From Table 9, it can be seen that the liquid crystal display devices 2 to 7 of the present invention are favorable with less color unevenness and point defects as compared with the liquid crystal display device 1 of the comparative example.

[Example 2]
In preparation of the polarizing plate 2 of Example 1, the optical film A is replaced with T1-1 to T1-10 as shown in Table 5 from T1-8, and the polarizing plates 11-20 are produced, and each polarizing plate after that. In the same manner as in Example 1, liquid crystal display devices 11 to 20 were manufactured.

  About the liquid crystal display devices 11-20, it carried out similarly to Example 1, and evaluated the color nonuniformity and the point defect. The results are shown in Table 10.

  From Table 10, it can be seen that the liquid crystal display device of the present invention is excellent with few color unevenness and point defects.

Example 3
In the production of the polarizing plate 2 of Example 1, the cellulose acylate resin used for the production of the optical film T2-2 (optical film B) was changed as shown in Table 11 using C5 to C1 to C7, and was carried out. In the same manner as in Example 1, polarizing plates 31 to 37 were prepared. Thereafter, liquid crystal display devices 31 to 37 were produced in the same manner as in Example 1 using the respective polarizing plates.

  The liquid crystal display devices 31 to 37 were evaluated for color unevenness and point defects in the same manner as in Example 1. The results are shown in Table 11.

  From Table 11, it can be seen that even within the present invention, particularly preferable results are obtained when the substitution degree of acetyl group is 2.6 to 2.7.

Example 4
In the production of the polarizing plate 2 of Example 1, the amount of the compound having the structure represented by the general formula (1) used for the production of the optical film T2-2 (optical film B) is as shown in Table 12. It changed and produced the polarizing plates 41-46 similarly to Example 1. FIG. Thereafter, liquid crystal display devices 41 to 46 were produced in the same manner as in Example 1 using the respective polarizing plates. And the film thickness of the optical film B was changed like Table 12, and it carried out similarly to Example 1, and produced the liquid crystal display devices 47-53.

  The liquid crystal display devices 41 to 53 were evaluated for color unevenness and point defects in the same manner as in Example 1. The results are shown in Table 12.

  From Table 12, even if it is in this invention, the addition amount of the compound which has a chemical structure represented by General formula (1) contained in the optical film B is 5-10 with respect to 100 mass parts of cellulose acylate resins. It turns out that it is preferable that the mass part is contained.

Example 5
In the production of the optical film T2-2 (optical film B) in the production of the polarizing plate 2 of Example 1, a retardation increasing agent was added as shown in Table 13, and the polarizing plates 61 to 73 were produced in the same manner as in Example 1. Was made. Thereafter, liquid crystal display devices 61 to 73 were produced in the same manner as in Example 1 using the respective polarizing plates.

  The liquid crystal display devices 61 to 73 were evaluated for color unevenness and point defects in the same manner as in Example 1. The results are shown in Table 13.

  From Table 13, it can be seen that even within the present invention, the optical film B preferably contains a nitrogen-containing retardation increasing agent.

Example 6
In preparation of the optical film T2-2 (optical film B) in preparation of the polarizing plate 2 of Example 1, a plasticizer is added like Table 14, and the polarizing plates 81-96 are produced like Example 1. FIG. did. Thereafter, liquid crystal display devices 81 to 96 were produced in the same manner as in Example 1 using the respective polarizing plates.

  The liquid crystal display devices 81 to 96 were evaluated for color unevenness and point defects in the same manner as in Example 1. The results are shown in Table 14.

Example 7
<< Production of Polarizing Plate 101 >>
A polarizing plate 101 was prepared in the same manner as the polarizing plate 2 in Example 1.

<< Production of Polarizing Plate 102 >>
In the production of the polarizing plate 2 in Example 1, the polarizing plate was similarly used except that the following radical polymerization type adhesive layer forming coating solution 2 was used as the adhesive layer between the polarizer and the optical films A and B. 102 was produced. This method of forming the adhesive layer is referred to as “UV adhesion 2”.

(Preparation of coating solution 2 for forming an adhesive layer: radical polymerization type)
What mixed 3 mass parts of photoinitiators (BASF Japan Co., Ltd .; brand name Irgacure 127) with 100 mass parts of N-hydroxyethyl acrylamide was used as the coating liquid 2 for contact bonding layer formation.

<< Production of Polarizing Plate 103 >>
In the production of the polarizing plate 2, the optical film A and the polarizer and the optical film B and the polarizer were bonded to each other through the following steps 1 to 5 after preparing the polarizer in the same manner as in Example 1.

  Process 1: Retardation films T1-8 and T2 which were immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water, dried and subjected to saponification treatment on the side to be bonded to the polarizer -2.

  Process 2: The said polarizer was immersed in the polyvinyl alcohol adhesive tank of 2 mass% of solid content for 1-2 seconds.

  Step 3: Excess adhesive adhered to the polarizer in Step 2 was lightly wiped off and placed on the retardation film T2-2 processed in Step 1.

  Step 4: The retardation film T2-2, the polarizer, and the back surface T1-8 laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm 2 and a conveyance speed of about 2 m / min.

Step 5: A sample obtained by bonding the polarizer prepared in Step 4 and the retardation films T2-2 and T1-8 in a dryer at 80 ° C. was dried for 2 minutes to prepare a polarizing plate 103. << Liquid Crystal Display Device Production of
Using the produced polarizing plates 101 to 103, liquid crystal display devices 101 and 102 were produced in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The results are shown in Table 15.

  From Table 15, it can be seen that the active energy ray-curable adhesive is excellent in reducing color unevenness.

Example 8
In preparation of the optical film T2-2 (optical film B) in preparation of the polarizing plate 2 of Example 1, a cellulose acylate resin, a compound having a structure represented by the general formula (1), a retardation increasing agent, plasticity Polarizers 110 to 150 were produced in the same manner as in Example 1, except that the type and amount of the agent and the film thickness of the optical film B were changed as shown in Table 16. Thereafter, liquid crystal display devices 110 to 150 were produced in the same manner as in Example 1 using the respective polarizing plates.

  The liquid crystal display devices 110 to 150 were evaluated for color unevenness and point defects in the same manner as in Example 1. The results are shown in Table 16 and Table 17.

Example 9
As an optical film B, a cellulose acylate film T2-131 having a three-layer structure was produced by the three-layer simultaneous casting method (co-casting method) according to the following procedure.

<< Production of Retardation Film T2-131 >>
Using the co-casting die shown in FIG. 2, a cellulose acylate film T2-131 having a three-layer structure (C4 / C1 / C4) is produced by a three-layer simultaneous casting method (co-casting method) according to the following procedure. did.

(Preparation of dope)
In the preparation of the main dope of Example 1, the cellulose acylate was changed from C5 to C1, C4, and the amounts of the compound having the structure represented by the general formula (1), the retardation increasing agent and the plasticizer shown in Table 17 were as follows. In addition, a core dope C and a skin dope S were prepared.

(Film forming process)
Using the dope, from the endless belt surface side which is the metal support for casting shown in FIG. 2, the dope S as the skin layer (B surface), the dope C as the core layer, and the skin layer (A surface) Dope S is supplied to the co-casting die 50 at the same time, and is a multilayer structure composed of a skin layer (B surface) 61 / core layer 62 / skin layer (A surface) 63 by a single casting operation. Web 60 was fed onto an endless belt. The supply amount of each dope was such that the film thickness of each layer after the drying was finally completed was skin layer (B surface) / core layer / skin layer (A surface) = 5 μm / 40 μm / 5 μm.

On the metal support 56 for casting, the organic solvent in the obtained dope film was evaporated until the residual solvent amount reached 100% by mass to form a web, and then the web was peeled from the stainless steel band support. The obtained web was further pre-dried at 110 ° C. for 10 minutes, and then the web was stretched 1.3 times with respect to the original width in the TD direction at 160 ° C. with a tenter. The residual solvent amount of the web at the start of stretching was 2.0% by mass. After stretching with a tenter, relaxation is performed at 130 ° C. for 5 minutes, and thereafter, the temperature is maintained at 135 ° C. by a dryer (bending zone), and facing the A side of the web by a conveying roller in the dryer zone. The diameter and arrangement of the transport rollers are set so that the value of 1 / a is 0.040 mm ⁻¹ when the radius when the B surface is alternately bent inward is a (mm), 80 The web was conveyed at a conveyance speed of 20 m / min by repeating the bending of the times.

  The obtained film was slit to 2.0 m width, 10 mm wide and 5 μm knurled at both ends of the film, wound on a core of 15.24 cm in inner diameter with an initial tension of 220 N / m and a final tension of 110 N / m. A retardation film T2-131 having a long three-layer structure having a thickness of 4000 m and a film thickness of 50 μm was obtained.

  Next, T1-8 was used as the optical film A, and the polarizing plate 161 was produced in the same manner as in Example 1. Thereafter, a liquid crystal display device 161 was produced using the polarizing plate 161 in the same manner as in Example 1.

  The liquid crystal display device 161 was evaluated for color unevenness and point defects in the same manner as in Example 1. The results are shown in Table 18.

  It can be seen that the liquid crystal display device 161 of the present invention is excellent in reducing color unevenness and point defects.

  The polarizing plate of the present invention can provide a polarizing plate in which the occurrence of color unevenness and point-like defects is suppressed, and can provide a liquid crystal display device having the polarizing plate.

DESCRIPTION OF SYMBOLS 100 Liquid crystal display device 101A, 101B Polarizing plate 101C Liquid crystal cell 102 Optical film A
103A, 103B Active energy ray-curable adhesive 104 Polarizer 105 Optical film B
106 Adhesive layer 107 Liquid crystal layer 108A, 108B Glass substrate BL Backlight 50 Co-casting die 51 Base part 53, 55 Layer B, Layer C slit 54 Layer A slit 56 Metal support 57, 59 Layer B, Layer C Dope for layer 58 Dope for layer A 60 multilayer web 61 skin layer 62 core layer 63 skin layer

Claims (13)

An optical film A, a polarizer and an optical film B are polarizing plates laminated in this order, and the optical film A is an optical film containing at least one of an acrylic resin or a polyester resin, and the optical film B is a cellulose acylate resin having an acyl group substitution degree in the range of 2.1 to 2.70, and any of compounds having structures represented by the following formulas (1-1) to (1-3) A polarizing plate comprising a retardation film containing

The retardation value Ro in the in-plane direction and the retardation value Rt in the thickness direction of the optical film B are within the following ranges, respectively, in an environment of 23 ° C and 55% RH. 1. The polarizing plate according to 1.
Ro: 20 to 130 nm
Rt: 100 to 300 nm   The polarizing plate according to claim 1 or 2, wherein the film thickness of the optical film B is in a range of 10 to 90 µm.   The cellulose acylate resin contained in the optical film B is a cellulose acetate resin having an acetyl group substitution degree in the range of 2.1 to 2.70, according to any one of claims 1 to 3. The polarizing plate according to one item.   The cellulose acylate resin contained in the optical film B is a cellulose acetate resin having a degree of acetyl group substitution in the range of 2.6 to 2.70, according to any one of claims 1 to 4. The polarizing plate according to one item. The optical film B is, the polarizing plate according to any one of claims 1 to 5, characterized that you containing a compound having a structure represented by the formula (1-2). The water vapor permeability at 40 ° C and 90% RH of the optical film A is in the range of ^{20 to} 120 g / m ² · 24 hr, The optical film A according to any one of claims 1 to 6, Polarizing plate.   8. The polarizing plate according to claim 1, wherein the optical film B has a thickness in a range of 10 to 40 μm.   The said optical film B contains the nitrogen-containing phase difference increasing agent, The polarizing plate as described in any one of Claim 1- Claim 8 characterized by the above-mentioned.   The nitrogen-containing retardation increasing agent is at least one selected from compounds having a carbazole ring, a quinoxaline ring, a benzoxazole ring, an oxadiazole ring, an oxazole ring, a triazole ring, and a pyrazole ring. Item 10. The polarizing plate according to item 9. The polarizing plate according to claim 9, wherein the nitrogen-containing retardation increasing agent is a compound having a structure represented by the following general formula (3).

(In the formula, A ₁ , A ₂ and B each independently represent an alkyl group, a cycloalkyl group, an aromatic hydrocarbon ring or an aromatic heterocyclic ring. T ₁ and T ₂ are each independently a pyrrole ring. , Pyrazole ring, imidazole ring, 1,2,3-triazole ring or 1,2,4-triazole ring, L ₁ , L ₂ , L ₃ and L ₄ are each independently a single bond or 2 or less. Represents a divalent linking group linked via an atom of n. N represents an integer of 0 to 5.)   The said optical film A and the said optical film B are each bonded with the said polarizer using an active energy ray hardening adhesive, The any one of Claim 1 to 11 characterized by the above-mentioned. The polarizing plate as described in.   A liquid crystal display device comprising the polarizing plate according to any one of claims 1 to 12.

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