JP2013130838A - Cellulose acylate film, polarizing plate protective film, polarizing plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cellulose acylate film on which an activation energy ray curable layer is placed, whose adhesion with the activation energy ray curable layer is sufficiently maintained even when being irradiated with light for a long term, and which is not colored even when being stored for a long term under a high temperature and high humidity environment.SOLUTION: A cellulose acylate film contains cellulose acylate, and 0.001 mass% or larger and 5 mass% or smaller of a hindered amine-based compound with respect to the cellulose acylate. The amount of iron components in the film is 5 ppm or smaller.

Description

  The present invention relates to a cellulose acylate film, a polarizing plate protective film, a polarizing plate using the polarizing plate protective film, and a liquid crystal display device.

  In recent years, liquid crystal display devices have been increased in size mainly for TV applications, and accordingly, higher image quality and lower price have been demanded. In the future, the frequency of outdoor use is expected to increase mainly for electronic signage applications, and a liquid crystal display device that can withstand use in a harsher environment than before is demanded.

  On the other hand, the surface of the viewer-side polarizing plate used in the liquid crystal display device is required to be provided with functions such as scratch resistance, antireflection, and antistatic. As a method for imparting the function, as a protective film of a polarizing plate, a functional layer is formed by coating an active energy ray cured layer formed using a compound that is cured by irradiation of active energy rays on a cellulose acylate film or the like. It is common to use a polarizing plate protective film with a functional layer.

  In outdoor applications, even more severe durability is required for the functional layer than in indoor applications. Among them, stability to light is a particularly important item, but the conventional functional layer has a problem that it easily peels off from the cellulose acylate film when irradiated with light for a long time, and improvement has been demanded.

  As means for improving the light resistance of a resin film, it is common to add an ultraviolet absorber or an antioxidant. For example, Patent Document 1 discloses an ultraviolet absorber having a melting point of 20 ° C. or less and a hindered amine antioxidant. A cellulose acylate film is disclosed.

  On the other hand, improvement of display performance by reducing impurities in cellulose acylate has also been studied, and Patent Document 2 discloses a bright spot failure by controlling the content of Fe component in the cellulose acylate film. An improved method is disclosed.

JP 2001-72782 A Japanese Patent No. 4390117

However, when the inventor examined the method described in Patent Document 1, the film obtained by this method is about adhesion between the functional layer and the cellulose acylate film when irradiated with light for a long time. Although a certain improvement effect is recognized, it has been found that there is a problem that the film becomes yellowish when stored at high temperature and high humidity for a long time.
The present invention has been made in view of such circumstances, and the problem to be solved by the present invention is that the active energy cured layer is laminated, and even when irradiated with light for a long time, An object of the present invention is to provide a cellulose acylate film whose adhesion is sufficiently maintained and which does not color even when stored for a long time in a high temperature and high humidity environment. Moreover, it is a polarizing plate protective film which has an active energy ray hardening layer on a cellulose acylate film, Comprising: Even if light is irradiated for a long time, adhesion between an active energy ray hardening layer and a cellulose acylate film is fully maintained. The polarizing plate protective film is provided. Still another object of the present invention is to provide a polarizing plate and a liquid crystal display device using the polarizing plate protective film.

  The cellulose acylate film usually contains about 0 to 10 ppm of iron (Fe) component. These are considered to be derived from the raw material cellulose acylate and additives, or mixed in the film production process. The present inventor has shown that the phenomenon in which a cellulose acylate film to which a hindered amine compound is added is yellowish in a high-temperature and high-humidity environment is promoted by the presence of a metal content, particularly an iron (Fe) component, in the cellulose acylate film. And that the above phenomenon is also related to the amount of hindered amine compound added. And the content of the metal component (especially Fe component) in the cellulose acylate film is controlled within a specific range, and the hindered amine compound is added within the specific range, whereby the high temperature and high humidity environment of the cellulose acylate film is obtained. It was found that the coloration below could be greatly suppressed.

  That is, the present invention has the following configuration.

[1]
A cellulose acylate film and a cellulose acylate film containing a hindered amine compound in an amount of 0.001% by mass to 5% by mass with respect to the cellulose acylate, wherein the amount of iron component contained in the film is 5 ppm or less. A cellulose acylate film.
[2]
The cellulose acylate film according to [1], wherein the number average molecular weight of the hindered amine compound is 500 or more and 10,000 or less.
[3]
The b ^* (L ^* a ^* b ^* chromaticness index in the color system) measured by stacking 10 films after being stored for 1000 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90% is 1 or more and 8 or less. The cellulose acylate film according to the above [1] or [2].
[4]
The polarizing plate protective film which has an active energy ray hardening layer on the cellulose acylate film as described in any one of said [1]-[3].
[5]
Having a polarizer and at least one polarizing plate protective film,
The polarizing plate protective film is the polarizing plate protective film according to the above [4], and the surface of the polarizing plate protective film opposite to the side having the active energy cured layer with respect to the cellulose acylate film is the polarizer. The polarizing plate by which the said polarizing plate protective film and the said polarizer were bonded together so that it might become a side.
[6]
The liquid crystal display device which has at least 1 polarizing plate protective film as described in said [4], or the polarizing plate as described in said [5].

According to the present invention, when the active energy ray-cured layer is provided, the adhesiveness with the active energy ray-cured layer is sufficiently maintained even when light is irradiated for a long time, and the active energy ray-cured layer is stored for a long time in a high temperature and high humidity environment. Even in this case, a cellulose acylate film that hardly changes color can be obtained.
Moreover, it is a polarizing plate protective film which laminated | stacked the active energy ray cured layer on the cellulose acylate film, Comprising: Adhesiveness between an active energy ray cured layer and a cellulose acylate film is enough even if irradiated for a long period of time A polarizing plate protective film that is maintained and can maintain good polarization performance even when used in a polarizing plate for a long period of time is obtained. Furthermore, according to the present invention, a highly durable polarizing plate using the film can be provided. Further, by incorporating a polarizing plate using the film into a liquid crystal display device, a liquid crystal display device with improved durability can be provided.

It is a schematic sectional drawing of an example of the liquid crystal display device of this invention.

Hereinafter, the cellulose acylate film, the polarizing plate protective film, and the liquid crystal display device of the present invention will be described in detail.
The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Cellulose acylate film, polarizing plate protective film]
The cellulose acylate film of the present invention contains cellulose acylate and a hindered amine compound in an amount of 0.001% by mass to 5% by mass with respect to the cellulose acylate, and the content of Fe component is 5 ppm or less.

  Hereinafter, the cellulose acylate film of the present invention and the cellulose acylate film of the polarizing plate protective film of the present invention will be described first.

1. Cellulose acylate film The cellulose acylate film used in the present invention contains cellulose acylate and a hindered amine compound in an amount of 0.001% by mass to 5% by mass with respect to the cellulose acylate, and the content of Fe component is 5 ppm. It is as follows.

<1-1: Cellulose acylate>
Cellulose acylate raw material cellulose used in the cellulose acylate film includes cotton linter (also referred to as “linter”) and wood pulp (hardwood pulp, softwood pulp), and any cellulose acylate obtained from any raw material cellulose. The rate can be used, and in some cases, it may be mixed. 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 cellulose acylate used in the cellulose acylate film may have only one type of acyl group, or two or more types of acyl groups may be used. The cellulose acylate used for the cellulose acylate film preferably has an acyl group having 2 to 4 carbon atoms as a substituent. Examples of the acyl group having 2 to 4 carbon atoms include an acetyl group, a propionyl group, and a butanoyl group, and an acetyl group is preferable. When two or more kinds of acyl groups are used, it is preferable that one of them is an acetyl group. These cellulose acylates can produce a solution having a preferable solubility, and in particular, a non-chlorine organic solvent can be used to produce a good solution. Furthermore, it becomes possible to produce a solution having a low viscosity and good filterability.

  The cellulose acylate preferably used in the present invention will be described in detail. Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by acylating part or all of these hydroxyl groups with an acyl group. The degree of acyl substitution means the sum of the ratios of acylation of the hydroxyl groups of cellulose located at the 2-position, 3-position and 6-position (100% acylation at each position is substitution degree 1).

  The total acyl substitution degree of the cellulose acylate is preferably 2.0 to 2.97, more preferably 2.5 or more and less than 2.97, and preferably 2.70 to 2.95. Particularly preferred.

  The acyl group having 2 or more carbon atoms of the cellulose acylate may be an aliphatic group or an aromatic group and is not particularly limited. Cellulose acylates substituted with these acyl groups are, for example, cellulose alkyl carbonyl esters, alkenyl carbonyl esters, aromatic carbonyl esters, aromatic alkyl carbonyl esters, and the like, and each may further have a substituted group. Good. Preferred examples of the acyl group include acetyl group, propionyl group, butanoyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, Examples thereof include an isobutanoyl group, a tert-butanoyl group, a cyclohexanecarbonyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, and a cinnamoyl group. Among these, an acetyl group, a propionyl group, a butanoyl group, a dodecanoyl group, an octadecanoyl group, a tert-butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, a cinnamoyl group, and the like are more preferable, and an acetyl group is particularly preferable. A propionyl group and a butanoyl group (when the acyl group has 2 to 4 carbon atoms), more preferably an acetyl group (when the cellulose acylate is cellulose acetate).

  In the acylation of cellulose, when an acid anhydride or acid chloride is used as an acylating agent, an organic acid such as acetic acid or methylene chloride is used as an organic solvent as a reaction solvent.

As the catalyst, when the acylating agent is an acid anhydride, a protic catalyst such as sulfuric acid is preferably used, and when the acylating agent is an acid chloride (for example, CH ₃ CH ₂ COCl), Basic compounds are used.

  The most common industrial synthesis method of cellulose mixed fatty acid ester is to use cellulose corresponding to fatty acid corresponding to acetyl group and other acyl groups (acetic acid, propionic acid, valeric acid, etc.) or their acid anhydrides. This is a method of acylating with a mixed organic acid component.

  The cellulose acylate can be synthesized, for example, by the method described in JP-A-10-45804.

The metal content of the cellulose acylate of the present invention is preferably controlled to a value below a certain value from the viewpoint of suppressing discoloration of the film when a hindered amine compound is added to the film.
The content of Fe component in the cellulose acylate of the present invention is 5 ppm or less, more preferably 3 ppm or less, still more preferably 1 ppm or less.
Further, the content of the Mg component in the cellulose acylate film of the present invention is preferably 50 ppm or less, more preferably 20 ppm or less, and still more preferably 10 ppm or less.
The ppm is based on mass.

  The cellulose acylate film preferably contains 5 to 99% by mass of cellulose acylate as a resin from the viewpoint of moisture permeability, more preferably 20 to 99% by mass, and particularly preferably 50 to 95% by mass.

<1-2: Hindered amine compound>
A hindered amine compound (hereinafter also referred to as “HALS”) functions as an antioxidant and has a structure having a bulky organic group (for example, a bulky branched alkyl group) in the vicinity of the N atom. This is a known compound and is described, for example, in US Pat. No. 4,619,956, columns 5-11 and US Pat. No. 4,839,405, columns 3-5. As such, 2,2,6,6-tetraalkylpiperidine compounds, or their acid addition salts or complexes thereof with metal compounds are included. Such compounds include those of the following general formula (2).

In the above formula, R1 and R2 are a hydrogen atom or a substituent.
The substituent represented by R1 is not particularly limited, but a substituent bonded to the piperidine ring by a nitrogen atom or an oxygen atom is preferable, and an amino group, hydroxyl group, alkoxy group, aryloxy group which may have a substituent An acyloxy group is more preferable, and an amino group, a hydroxyl group, an alkoxy group, or an acyloxy group having an alkyl group, an aryl group, or a heterocyclic group as a substituent is more preferable.
The substituent represented by R2 is not particularly limited, but is an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms such as a methyl group, an ethyl group, Isopropyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl, cyclohexyl group, etc.), alkenyl group (preferably having 2 to 20 carbon atoms, More preferably, it is 2-12, Most preferably, it is 2-8, for example, a vinyl group, an allyl group, 2-butenyl group, 3-pentenyl group etc.), an alkynyl group (preferably 2-20 carbon atoms). More preferably, it is 2-12, Most preferably, it is 2-8, for example, a propargyl group, 3-pentynyl group, etc. are mentioned), an aryl group ( The number of carbon atoms is preferably 6 to 30, more preferably 6 to 20, particularly preferably 6 to 12, and examples thereof include a phenyl group, a biphenyl group, a naphthyl group, and the like, and an amino group (preferably the number of carbon atoms). 0 to 20, more preferably 0 to 10, particularly preferably 0 to 6, and examples thereof include an amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dibenzylamino group, and the like, and an alkoxy group (preferably). Is preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a butoxy group, and a cyclohexyloxy group.

  Specific examples of hindered amines include 4-hydroxy-2,2,6,6-tetramethylpiperidine, 1-allyl-4-hydroxy-2,2,6,6-tetramethylpiperidine, 1-benzyl-4-hydroxy -2,2,6,6-tetramethylpiperidine, 1- (4-tert-butyl-2-butenyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2, 2,6,6-tetramethylpiperidine, 1-ethyl-4-salicyloyloxy-2,2,6,6-tetramethylpiperidine, 4-methacryloyloxy-1,2,2,6,6-pentamethyl Piperidine, 1,2,2,6,6-pentamethylpiperidin-4-yl-β (3,5-di-t-butyl-4-hydroxyphenyl) -propionate, 1-benzyl- , 2,6,6-tetramethyl-4-piperidinylmaleate, (di-2,2,6,6-tetramethylpiperidin-4-yl) -adipate, (di-2,2, 6,6-tetramethylpiperidin-4-yl) -sebacate, (di-1,2,3,6-tetramethyl-2,6-diethyl-piperidin-4-yl) -sebacate, (di-1-allyl) -2,2,6,6-tetramethyl-piperidin-4-yl) -phthalate, 1-acetyl-2,2,6,6-tetramethylpiperidin-4-yl-acetate, trimellitic acid-tri- (2 , 2,6,6-tetramethylpiperidin-4-yl) ester, 1-acryloyl-4-benzyloxy-2,2,6,6-tetramethylpiperidine, dibutyl-malonic acid-di- (1,2, 2 , 6,6-pentamethyl-piperidin-4-yl) -ester, dibenzyl-malonic acid-di- (1,2,3,6-tetramethyl-2,6-diethyl-piperidin-4-yl) -ester, Dimethyl-bis- (2,2,6,6-tetramethylpiperidin-4-oxy) -silane, tris- (1-propyl-2,2,6,6-tetramethylpiperidin-4-yl) -phosphite , Tris- (1-propyl-2,2,6,6-tetramethylpiperidin-4-yl) -phosphate, N, N'-bis- (2,2,6,6-tetramethylpiperidin-4-yl ) -Hexamethylene-1,6-diamine, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6) , 6 Pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, N, N′-bis- (2,2,6,6-tetramethylpiperidin-4-yl) -hexamethylene-1,6 -Diacetamide, 1-acetyl-4- (N-cyclohexylacetamido) -2,2,6,6-tetramethyl-piperidine, 4-benzylamino-2,2,6,6-tetramethylpiperidine, N, N '-Bis- (2,2,6,6-tetramethylpiperidin-4-yl) -N, N'-dibutyl-adipamide, N, N'-bis- (2,2,6,6-tetramethylpiperidine -4-yl) -N, N'-dicyclohexyl- (2-hydroxypropylene), N, N'-bis- (2,2,6,6-tetramethylpiperidin-4-yl) -p-xylylene-diam 4- (bis-2-hydroxyethyl) -amino-1,2,2,6,6-pentamethylpiperidine, 4-methacrylamide-1,2,2,6,6-pentamethylpiperidine, α-cyano -Β-methyl-β- [N- (2,2,6,6-tetramethylpiperidin-4-yl)]-amino-acrylic acid methyl ester.

  Furthermore, N, N ′, N ″, N ′ ″-tetrakis- [4,6-bis- [butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino]- Triazin-2-yl] -4,7-diazadecane-1,10-diamine, dibutylamine and 1,3,5-triazine N, N'-bis (2,2,6,6-tetramethyl-4- Piperidyl) -1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine polycondensate (BAMIS CHIMASSORB 2020FDL), dibutylamine and 1,3, Polycondensation product of 5-triazine and N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1,1,3,3-tetramethylbutyl) amino -1,3,5 -Triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] (CHIMASSORB 944FDL manufactured by BASF), 1,6-hexanediamine-N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) and morpholine-2,4,6-trichloro-1 , 3,5-triazine polycondensate, poly [(6-morpholino-s-triazine-2,4-diyl) [(2,2,6,6, -tetramethyl-4-piperidyl) imino]- High molecular weight HALS in which a plurality of piperidine rings are bonded via a triazine skeleton, such as hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]]; dimethyl succinate and 4 -Polymer with hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4- Piperidine rings such as mixed esterified products of piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane are ester-bonded. Examples include, but are not limited to, a high molecular weight HALS bonded via a. Among these, polycondensates of dibutylamine, 1,3,5-triazine and N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1, 1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2 , 2,6,6-tetramethyl-4-piperidyl) imino}], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, etc. Those having a molecular weight (Mn) of 2,000 to 5,000 are preferred.

  Preferred examples of the hindered amine compound include the following specific example (1) (Sunlizer HA-622, manufactured by Sort Co., Ltd.) and specific example (2).

  Among the above specific examples, CHIMASSORB 2020FDL (CAS-No. 192268-64-7), CHIMASSORB 944FDL (CAS-No. 71878-19-8), and TINUVIN 770DF manufactured by BASF (former Ciba Specialty Chemicals) (CAS-No. 52829-07-9), Siasorb UV-3346 (CAS-No. 82541-48-7) manufactured by Sun Chemical Co., Ltd., Siasorb UV-3529 (CAS-No. 193098-40-7), TINUVIN 123 (CAS-No. 129757-67-1), TINUVIN 152 (CAS-No. 191743-75-6), FLAMESTABNOR 116FF (CAS-No. 191680-81-6) are commercially available. Is suitable because have excellent availability and.

  In addition, although the said hindered amine type compound may be obtained commercially as mentioned above, you may use what was manufactured by the synthesis | combination. There is no restriction | limiting in particular as a synthesis method of the said hindered amine type compound, It can synthesize | combine by the method in a normal organic synthesis. Moreover, as a production | generation method, the method using distillation, recrystallization, reprecipitation, and a filter agent and adsorption agent can be used suitably. In addition, the commercially available products that are available at low cost are not limited to the hindered amine compounds, but may be mixtures. In the present invention, any of these embodiments may be obtained commercially. It can be used regardless of the composition, melting point, acid value and the like.

The hindered amine compound used in the present invention may be a low molecular weight polymer or a polymer having a repeating unit, but the hindered amine compound is in the vicinity of the interface between the active energy ray cured layer and the cellulose acylate film. High molecular weight is more preferable for uneven distribution of. On the other hand, if the molecular weight is too high, the compatibility with cellulose acylate is insufficient, and the haze of the film becomes high.
The hindered amine compound preferably has a number average molecular weight of 300 to 100,000, more preferably 500 to 10,000, still more preferably 700 to 8,000, and particularly preferably 1,000 to 5,000.

The hindered amine compound used in the present invention is preferably dissolved in a ketone solvent in an amount of 0.01% by mass or more. By using such a hindered amine compound, the hindered amine compound added to the cellulose acylate film when producing the polarizing plate protective film of the present invention forms an active energy ray cured layer described later. It is preferable because the hindered amine compound is contained in the active energy ray-cured layer after dissolving and moving in a preferably used ketone solvent.
In addition, about the preferable aspect of the said ketone solvent, it mentions later in description of an active energy ray hardening layer.

The cellulose acylate film contains 0.001% by mass to 5% by mass of a hindered amine compound with respect to the cellulose acylate. The hindered amine compound is preferably contained in an amount of 0.001% by mass or more and 2% by mass or less, more preferably 0.01% by mass or more and 1.5% by mass or less, and 0.05% by mass with respect to cellulose acylate. It is particularly preferable that the content is from 1.0% to 1.0% by mass.
When the content of the hindered amine compound is less than 0.001% by mass with respect to the cellulose acylate film, sufficient adhesion between the active energy ray-curable functional layer and the cellulose acylate film cannot be ensured. In addition, in the case of 5 mass% or less, it becomes difficult to produce a hindered amine type bleed out, and it is preferable from a viewpoint of the improvement of the polarizing performance of a polarizing plate.

<1-3: UV absorber>
The ultraviolet absorbent added to the cellulose acylate film of the present invention is preferably a benzotriazole ultraviolet absorbent having a molecular weight of 400 or more, no halogen atom, and a melting point of 30 ° C. or more. The ultraviolet absorber satisfying the above requirements is preferable because it does not inhibit radical scavenging by the hindered amine compound on the film surface when used in combination with the hindered amine compound.
As the benzotriazole-based UV absorber of the present invention, preferably used are Tinuvin 900 (molecular weight 448) manufactured by BASF Corporation, Tinuvin 928 (molecular weight 442), Adeka Stub LA-31 (molecular weight 659) manufactured by ADEKA Corporation, and the like. Can do.

  The addition method of the ultraviolet absorber of the present invention may be added directly, but in-line addition with excellent productivity is preferable. In-line addition is a method in which an in-line mixer or the like is added to the dope composition after dissolving in advance in an organic solvent (for example, methanol, ethanol, methylene chloride, etc.).

The addition amount of the ultraviolet absorber of the present invention is preferably from 0.1% by mass to 5% by mass, and more preferably from 1% by mass to 5% by mass. When the amount of the ultraviolet absorber added is large, deterioration of the polarizer due to light can be suppressed. On the other hand, when there is too much ultraviolet absorber addition amount, an ultraviolet absorber will phase-separate from a cellulose acylate, and it will become easy to raise the haze of a film. By adjusting the ultraviolet absorber concentration within the above range, light resistance can be imparted while maintaining the transparency of the film.
Moreover, melting | fusing point of the ultraviolet absorber of this invention is 30 degreeC or more, 50 degreeC or more is preferable and 70 degreeC or more is more preferable. As an upper limit, 200 degrees C or less is preferable and 150 degrees C or less is more preferable.

<1-4: Other additives>
In the cellulose acylate film, in addition to the hindered amine compound (antioxidant) and the ultraviolet absorber, a plasticizer such as a polycondensation polymer, a phthalate ester, and a phosphate ester; an antioxidant; a matting agent, etc. Additives can also be added.

  The cellulose acylate film of the present invention preferably contains an aromatic terminal ester compound represented by the following general formula (3) from the viewpoint of improving the surface hardness of the film.

General formula (3) B- (GA) n-GB
(In the formula, B independently represents a benzene monocarboxylic acid residue. G independently represents an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or 4 carbon atoms. Represents an oxyalkylene glycol residue having ˜12, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 0 or more.)

The aromatic terminal ester compound represented by the general formula (3) includes a benzene monocarboxylic acid residue represented by B, an alkylene glycol residue, and an oxyalkylene glycol residue represented by G in the general formula (3). Or an aryl glycol residue and an alkylene dicarboxylic acid residue or aryl dicarboxylic acid residue represented by A, and can be obtained by a reaction similar to that of a normal polyester (polycondensation ester).
In the present specification, the “residue” is a partial structure of the aromatic terminal ester compound represented by the general formula (3), and has the characteristics of the monomer forming the compound (polymer). Represents a partial structure. For example, the monocarboxylic acid residue formed from monocarboxylic acid R—COOH is R—CO—.

Examples of the benzene monocarboxylic acid in the benzene monocarboxylic acid residue include benzoic acid, paratertiary butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, amino There exist benzoic acid, acetoxybenzoic acid, etc., These can be used as a 1 type, or 2 or more types of mixture, respectively.
Of these, benzoic acid, orthotoluic acid, metatoluic acid, and p-toluic acid are preferable, and benzoic acid, orthotoluic acid, and metatoluic acid are more preferable.

The alkylene glycol in the alkylene glycol residue is an alkylene glycol having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms, more preferably 2 to 3 carbon atoms.
Examples of the alkylene glycol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl 1,3-propanediol, 1, 4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane) ), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol 1,6-hexanediol, 2,2,4- Trimethyl 1,3-pentanediol, 2-ethyl 1,3-hexanediol, 2-methyl 1,8-octanediol, 1 9-nonanediol, 1,10-decanediol, there are 1,12-octadecane diol, these glycols may be used alone or in combination.
Among these, 1,4-butanediol, ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol are preferable, and ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol are preferable. It is more preferable.

The oxyalkylene glycol in the oxyalkylene glycol residue is an oxyalkylene glycol having 4 to 12 carbon atoms, and the carbon number is preferably 4 to 8 and more preferably 4 to 6.
Examples of the oxyalkylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol and the like, and these glycols can be used as one kind or a mixture of two or more kinds.
Of these, diethylene glycol and dipropylene glycol are preferable, and more preferable.

The aryl glycol in the aryl glycol residue is an aryl glycol having 6 to 12 carbon atoms, and the carbon number is preferably 6 to 8.
Examples of the aryl glycol include hydroquinone, resorcin, bisphenol A, bisphenol F, and bisphenol, and these glycols can be used as one kind or a mixture of two or more kinds.
Of these, hydroquinone and resorcin are preferable, and hydroquinone is more preferable.

The alkylene dicarboxylic acid in the alkylene dicarboxylic acid residue is an alkylene dicarboxylic acid having 4 to 12 carbon atoms, and the carbon number is preferably 4 to 10 and more preferably 4 to 8.
Examples of the alkylenedicarboxylic acid include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, etc., and these are used as one kind or a mixture of two or more kinds, respectively. can do.
Of these, succinic acid and maleic acid are preferable, and succinic acid is more preferable.

The aryl dicarboxylic acid in the aryl dicarboxylic acid residue is an aryl dicarboxylic acid having 8 to 12 carbon atoms.
Examples of the aryl dicarboxylic acid include phthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and the like. These can be used as one kind or a mixture of two or more kinds, respectively.
Of these, 1,5-naphthalenedicarboxylic acid, phthalic acid, and terephthalic acid are preferable, and phthalic acid and terephthalic acid are more preferable.

  In General formula (3), 0-4 are preferable, as for n, 1-3 are more preferable, and 1-2 are still more preferable.

  The aromatic terminal ester compound of the present invention has a number average molecular weight of preferably 300 to 2000, more preferably 500 to 1500. The acid value is preferably 0.5 mgKOH / g or less, the hydroxyl value is 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl value is 15 mgKOH / g or less.

(Acid value and hydroxyl value of aromatic terminal ester compounds)
Here, the acid value means the number of milligrams of potassium hydroxide necessary for neutralizing the acid (carboxyl group present at the molecular end) contained in 1 g of the sample.
The hydroxyl value refers to the number of milligrams of potassium hydroxide required to neutralize acetic acid bonded to OH groups contained in 1 g of a sample.
The acid value and the hydroxyl value are measured according to JIS K0070.

  Although the specific compound of the aromatic terminal ester plasticizer which concerns on this invention below is shown, this invention is not limited to this.

  Hereinafter, the synthesis example of the aromatic terminal ester plasticizer which concerns on this invention is shown.

<Sample A-1 (Aromatic terminal ester sample)>
Into a reaction vessel, 820 parts (5 moles) of phthalic acid, 608 parts (8 moles) of 1,2-propylene glycol, 610 parts (5 moles) of benzoic acid and 0.30 parts of tetraisopropyl titanate as a catalyst are charged all at once. While stirring in an air stream, a reflux condenser was attached to reflux excess monohydric alcohol, and heating was continued at 130 to 250 ° C. until the acid value became 2 or less, and water produced was continuously removed. Next, the distillate is removed under reduced pressure of 6.65 × 10 ³ Pa to 4 × 10 ² Pa or less at 200 to 230 ° C., followed by filtration to obtain an aromatic terminal ester having the following properties. It was.
Viscosity (25 ° C., mPa · s): 19815
Acid value: 0.4

The content of the compound represented by the general formula (3) used in the present invention is preferably 2 to 20% by mass, and preferably 5 to 15% by mass in the cellulose acylate film with respect to the cellulose ester. Is more preferable.
In the cellulose acylate film of the present invention, two or more compounds represented by the general formula (3) may be contained from the viewpoint of reducing the haze of the film. As for the content when two or more kinds are used, the total amount is preferably in the above range. When using 2 or more types, it is especially preferable from a viewpoint of the haze reduction of a film to mix the compound from which n in the said structure differs.

(Plasticizer)
As the plasticizer used in the present invention, many compounds known as cellulose acylate plasticizers can be usefully used. As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Examples of phosphate esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP). Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethyl hexyl phthalate (DEHP). Examples of citrate esters include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalate plasticizers (DMP, DEP, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred.

(Antioxidant)
In the present invention, besides the hindered amine compound, a known antioxidant for the cellulose acylate film, such as 2,6-di-tert-butyl-4-methylphenol, 4,4′-thiobis- (6 -Tert-butyl-3-methylphenol), 1,1'-bis (4-hydroxyphenyl) cyclohexane, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,5-di-tert Phenolic or hydroquinone antioxidants such as -butylhydroquinone and pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] can be added. Further, tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,6-di-tert) It is preferable to use a phosphorus-based antioxidant such as -butyl-4-methylphenyl) pentaerythritol diphosphite and bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite. The addition amount of the antioxidant is preferably 0.05 to 5.0 parts by mass with respect to 100 parts by mass of cellulose acylate.

(Matting agent)
The cellulose acylate film may be added with a matting agent from the viewpoint of film slipperiness and stable production. The matting agent may be an inorganic compound matting agent or an organic compound matting agent.
Specific examples of the inorganic compound matting agent include silicon-containing inorganic compounds (for example, silicon dioxide, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, etc.), titanium oxide, and zinc oxide. , Aluminum oxide, barium oxide, zirconium oxide, strongtium oxide, antimony oxide, tin oxide, tin oxide / antimony, calcium carbonate, talc, clay, calcined kaolin, calcium phosphate, etc., more preferably silicon-containing inorganic compounds and oxides Although it is zirconium, since the turbidity of a cellulose acylate film can be reduced, silicon dioxide is particularly preferably used. 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 (manufactured by Nippon Aerosil Co., Ltd.) can be used. As the zirconium oxide fine particles, for example, those commercially available under trade names such as Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) can be used.
Preferable specific examples of the organic compound matting agent include, for example, polymers such as silicone resin, fluorine resin and acrylic resin, and among them, silicone resin is preferably used. Of the silicone resins, those having a three-dimensional network structure are particularly preferable. A commercial product having a trade name can be used.

  When these matting agents are added to the cellulose acylate solution, the method is not particularly limited, and there is no problem as long as a desired cellulose acylate solution can be obtained by any method. For example, an additive may be contained at the stage of mixing cellulose acylate and a solvent, or an additive may be added after preparing a mixed solution with cellulose acylate and a solvent. Further, it may be added and mixed immediately before casting the dope, which is a so-called immediately preceding addition method, and the mixing is used by installing screw-type kneading online. Specifically, a static mixer such as an in-line mixer is preferable, and the in-line mixer is, for example, a static mixer SWJ (Toray static type in-pipe mixer Hi-Mixer) (manufactured by Toray Engineering). Is preferred. In addition, regarding in-line addition, in order to eliminate density unevenness, particle aggregation, and the like, Japanese Patent Application Laid-Open No. 2003-053752 mixes additive liquids having different compositions into the main raw material dope in a method for producing a cellulose acylate film. An invention is described in which the distance L between the tip of the addition nozzle and the start end of the in-line mixer is 5 times or less the inner diameter d of the main raw material pipe, thereby eliminating concentration unevenness and aggregation of matte particles. As a more preferred embodiment, the distance (L) between the tip opening of the additive liquid supply nozzle having a composition different from that of the main raw material dope and the starting end of the in-line mixer is 10 times or less the inner diameter (d) of the supply nozzle tip opening. And that the in-line mixer is a static unstirred in-tube mixer or a dynamic agitated in-tube mixer. More specifically, it is disclosed that the flow rate ratio of the cellulose acylate film main raw material dope / in-line additive solution is 10/1 to 500/1, preferably 50/1 to 200/1. Furthermore, the additive is also added to Japanese Patent Application Laid-Open No. 2003-014933 of the invention aiming at a retardation film with little additive bleed-out, no delamination phenomenon, excellent slipperiness and excellent transparency. As a method to do this, it may be added to the melting pot, or a solution in which additives or additives are dissolved or dispersed between the melting pot and the co-casting die may be added to the dope being fed. However, in the latter case, it is described that it is preferable to provide a mixing means such as a static mixer in order to improve the mixing property.

  In the cellulose acylate film, if the matting agent is not added in a large amount, the haze of the film does not increase. When actually used in an LCD, inconveniences such as a decrease in contrast and generation of bright spots are unlikely 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 in the cellulose acylate film in a proportion of 0.01 to 5.0% by weight, and included in a proportion of 0.03 to 3.0% by weight with respect to the cellulose acylate. More preferably, it is particularly preferably included in a proportion of 0.05 to 1.0% by weight.

(Hue of film)
The hue of the cellulose acylate film in the present invention is preferably evaluated using the lightness index L ^* and the chromaticness index a ^* and b ^* in the L ^* a ^* b ^* color system recommended as the CIE uniform perception space. . Definitions of L ^* , a ^* , and b ^* are described in, for example, Color Electronics, published by Tokyo Denki University Press. The cellulose acylate film of the present invention preferably has a b ^* of 1 or more and 8 or less measured by stacking 10 films after being stored for 1000 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90%. More preferably, it is 2 or more and 7 or less, and most preferably 3 or more and 6 or less. By controlling the value of b ^* within the above range, display performance with excellent color reproducibility can be obtained when the cellulose acylate film is incorporated in a liquid crystal display device. The b ^* value of the cellulose acylate film controls the Fe content to 5 ppm or less, and suppresses the content of a compound having a group such as a phenolic hydroxyl group or an amine group that easily forms a colored structure by oxidation to 5 mass% or less. Can be controlled.

Next, how to obtain b ^* will be described.
Lightness index: L ^* = 116 (Y / Yn) ^1/3 −16
a ^* = 500 {(X / Xn) ¹ /3-(Y / Yn) ^1/3 }
b ^* = 200 {(Y / Yn) ¹ /3-(Z / Zn) ^1/3 }
However, Y / Yn> 0.008856
X / Xn> 0.008856
Z / Zn> 0.008856
Here, X, Y, and Z are tristimulus values in the XYZ color system of the sample.
Xn, Yn, Zn are the tristimulus values of the perfect diffuse reflection surface. If X / Xn, Y / Yn, Z / Zn has 0.008856 or less, the corresponding cubic root terms in the above equation It can be calculated by replacing with the following formula.
(X / Xn) ¹ /3-> 7.787 (X / Xn) +16/116
(Y / Yn) ¹ /3-> 7.787 (Y / Yn) +16/116
(Z / Zn) ^1/3 → 7.787 (Z / Zn) +16/116

(Haze)
The cellulose acylate film preferably has a haze of less than 0.20%, more preferably less than 0.15%, and particularly preferably less than 0.10%. By setting the haze to less than 0.2%, the contrast ratio when incorporated in a liquid crystal display device can be improved. In addition, there is an advantage that the transparency of the film becomes higher and it is easier to use as an optical film.

(Film thickness)
The cellulose acylate film preferably has an average film thickness of 30 to 100 μm, more preferably 30 to 80 μm, still more preferably 30 to 70 μm, and particularly preferably 30 to 60 μm, 30 Most preferably, it is ˜50 μm. By setting it to 30 μm or more, the handling property when producing a web-like film is improved, which is preferable. Moreover, by setting it as 70 micrometers or less, it is easy to respond to a humidity change and it is easy to maintain an optical characteristic.
Moreover, when the said cellulose acylate film has a laminated structure of three or more layers, it is preferable that the film thickness of a core layer is 30-70 micrometers, It is more preferable that it is 30-60 micrometers, It is 30-50 micrometers. Particularly preferred. When the cellulose acylate film of the present invention has a laminate structure of three or more layers, it is more preferable that the film thicknesses of the surface layers (skin A layer and skin B layer) on both sides of the film are both 0.5 to 20 μm. More preferably, it is 5-10 micrometers, and it is especially preferable that it is 0.5-3 micrometers.

(Film width)
The cellulose acylate film preferably has a film width of 700 to 3000 mm, more preferably 1000 to 2800 mm, and particularly preferably 1470 to 2500 mm.

(Metal content in film)
The iron (Fe) component in the cellulose acylate film of the present invention is preferably 5 ppm or less. By controlling the Fe component within the above range, when a hindered amine compound is used in combination, it is possible to suppress an increase in b ^* of the film after long-term storage in a high temperature and high humidity environment. Since it is impossible to eliminate at all, the lower limit in the range of 0.01 ppm to 5 ppm is preferable. More preferably, it is 0.01 ppm-3 ppm, Most preferably, it is 0.01 ppm-1 ppm.
The content of the Fe component in the cellulose acylate film can be controlled by carrying out the production of cellulose acylate under conditions where the Fe component in the reaction vessel is difficult to dissolve. For example, the content of the Fe component can be reduced by a method such as shortening the reaction time or performing the reaction at a low temperature in an acylation reaction performed under acidic conditions.

Regarding the magnesium (Mg) component, when a hindered amine compound is used in combination, it is preferable that the content in the film is small in order to promote an increase in b ^* of the film after long-term storage in a high-temperature and high-humidity environment. The content of the Mg component in the cellulose acylate film of the present invention is preferably 50 ppm or less, more preferably 20 ppm or less, and most preferably 10 ppm or less.
The content of the Mg component in the cellulose acylate film is obtained by reducing the amount of Mg ions used as a neutralizing agent when producing cellulose acylate (reducing the amount of acid catalyst or using Ca ions). Can be controlled.

  In the present invention, metal components such as a trace metal component, that is, an iron (Fe) content, a magnesium (Mg) content, and the like, are obtained by microdigest wet decomposition of a completely dried cellulose acylate, a cellulose acylate solution, or a cellulose acylate film, respectively. After pretreatment with an apparatus (sulfuric acid decomposition) and alkali melting, the amount was quantified by analysis using ICP-AES (inductively coupled plasma emission spectrometer).

<1-6: Manufacturing method of cellulose acylate film>
Hereafter, the manufacturing method of the cellulose acylate film used for this invention is demonstrated in detail.

  The cellulose acylate film is preferably produced by a solvent cast method. About the manufacture example of the cellulose acylate film using a solvent cast method, U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977, 2,492,978, 2,607,704, 2,739,069 and 2,739,070, British Patent Nos. 640731 and 736892, JP-B Nos. 45-4554, 49-5614, JP-A-60-176834, JP-A-60-203430, and JP-A-62-115035 can be referred to. The cellulose acylate film may be subjected to a stretching treatment. With respect to the stretching method and conditions, for example, refer to JP-A-62-115035, JP-A-4-152125, 4-284221, 4-298310, and 11-48271. can do.

(Casting method)
As a solution casting method, a method in which the prepared dope is uniformly extruded from a pressure die onto a metal support, and a method using a doctor blade in which the dope once cast on the metal support is adjusted with a blade is used. Although there is a method using a reverse roll coater that adjusts with a reverse rotating roll, a method using a pressure die is preferred. The pressure die includes a coat hanger type and a T die type, and any of them can be preferably used. In addition to the methods mentioned here, it can be carried out by various known methods for casting a cellulose triacetate solution, and each condition is set in consideration of differences in the boiling point of the solvent used. Thus, the same effects as those described in the respective publications can be obtained.

《Co-casting》
In forming the cellulose acylate film, a lamination casting method such as a co-casting method, a sequential casting method, or a coating method can be used.
When manufacturing by the co-casting method and the sequential casting method, first, a cellulose acetate solution (dope) for each layer is prepared. In the co-casting method (multi-layer simultaneous casting), a casting dope for each layer (which may be three layers or more) is simultaneously pressed from a separate slit or the like on a casting support (band or drum). This is a casting method in which the dope is extruded from the casting gies to be cast, and each layer is cast at the same time, peeled off from the support at an appropriate time, and dried to form a film.

  In the sequential casting method, the casting dope for the first layer is first extruded from the casting giusa on the casting support, cast, and dried on the second layer without drying or drying. Extrude the casting dope for casting from the casting gieser, cast the dope sequentially to the third layer or more, if necessary, peel it off from the support at an appropriate time, and dry it. This is a casting method for forming a film. In general, the core layer film is formed into a film by a solution casting method to prepare a coating solution to be applied to the skin layer. In this method, a coating film is applied and dried to form a film having a laminated structure.

The endlessly running metal support used to manufacture the cellulose acylate film includes a drum whose surface is mirror-finished by chrome plating and a stainless steel belt (which may be called a band) which is mirror-finished by surface polishing. Good) is used. One or more pressure dies may be installed above the metal support. Preferably 1 or 2 groups. When two or more are installed, the amount of dope to be cast may be divided into various ratios for each die, or the dope may be fed to the dies from each of a plurality of precision quantitative gear pumps. The temperature of the dope (resin solution) used for casting is preferably −10 to 55 ° C., more preferably 25 to 50 ° C. In that case, all solution temperatures in the process may be the same or different at different points in the process. If they are different, the temperature may be a desired temperature just before casting.
Moreover, there is no restriction | limiting in particular about the material of the said metal support body, However, It is more preferable that it is a product made from SUS (for example, SUS316).

(Extension process)
In the method for producing the cellulose acylate film, it is preferable to include a step of stretching the formed film. As described above, it is preferable that the optical compensation film of the present invention has improved wavelength dispersion characteristics. However, it is possible to impart such optical performance by a stretching treatment, and further, a desired letter is added to the cellulose acylate film. It is possible to provide a foundation. The stretching direction of the cellulose acylate film is preferably any of the film transport direction and the direction (width direction) perpendicular to the transport direction, but the direction following the film transport direction (width direction) is preferably the following film This is particularly preferable from the viewpoint of the polarizing plate processing process used.

  Methods for stretching in the width direction are described in, for example, JP-A-62-115035, JP-A-4-152125, JP-A-2842211, JP-A-298310, and JP-A-11-48271. Yes. In the case of stretching in the longitudinal direction, for example, the film is stretched by adjusting the speed of the film transport roller so that the film winding speed is higher than the film peeling speed. In the case of stretching in the width direction, the film can also be stretched by conveying while holding the width of the film with a tenter and gradually widening the width of the tenter. After the film is dried, it can be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine).

  The stretch ratio of the cellulose acylate film is preferably 1% to 200%, more preferably 5% to 100%, and particularly preferably 10% to 50%.

  When the cellulose acylate film is used as a protective film for a polarizer, in order to suppress light leakage when the polarizing plate is viewed obliquely, the transmission axis of the polarizer and an in-plane retardation of the resin film of the present invention are used. It is necessary to arrange the phase axes in parallel. Since the transmission axis of the roll film-like polarizer produced continuously is generally parallel to the width direction of the roll film, the roll film-like polarizer and the roll film-like cellulose acylate film are used. In order to continuously bond the protective film to be formed, the in-plane slow axis of the roll film-shaped protective film needs to be parallel to the width direction of the film. Therefore, it is preferable to stretch more in the width direction. In addition, the stretching treatment may be performed during the film forming process, or the raw film that has been formed and wound may be stretched, but in the production method of the present invention, the stretching is performed in a state containing a residual solvent. In order to carry out, it is preferable to extend | stretch in the middle of a film forming process.

(Dry)
The method for producing a cellulose acylate film includes a step of drying the cellulose acylate film and a step of stretching the resin film of the present invention after drying at a temperature of Tg-10 ° C. or higher. From the viewpoint of sex.

  The drying of the dope on the metal support, which is related to the production of the cellulose acylate film, is generally performed by supplying hot air from the surface side of the metal support (drum or belt), that is, from the surface of the web on the metal support. Contact method, a method of applying hot air from the back surface of the drum or belt, a temperature-controlled liquid is brought into contact with the back surface opposite to the belt or drum dope casting surface, and the drum or belt is heated by heat transfer to increase the surface temperature. Although there is a back surface liquid heat transfer method to be controlled, the back surface liquid heat transfer method is preferable. The surface temperature of the metal support before casting may be any number as long as it is not higher than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the metal support, the temperature should be set to 1 to 10 ° C. lower than the boiling point of the lowest boiling solvent. Is preferred. Note that this is not the case when the casting dope is cooled and peeled off without drying.

(Peeling)
The method for producing the cellulose acylate film preferably includes a step of peeling the dope film from the metal support. There is no restriction | limiting in particular about the peeling method in the manufacturing method of the said cellulose acylate film, When a well-known method is used, peelability can be improved.

  The film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the metal support speed, and the like so as to obtain a desired thickness.

  The length of the cellulose acylate film obtained as described above is preferably wound at 100 to 10000 m per roll, more preferably 500 to 7000 m, and still more preferably 1000 to 6000 m. When winding, it is preferable to give knurling to at least one end, the knurling width is preferably 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is preferably 0.5 to 500 μm, more preferably 1 to 200 μm. is there. This may be a single push or a double push.

  In general, in a large screen display device, since the contrast reduction and coloration in an oblique direction become remarkable, the cellulose acylate film is particularly suitable for use in a large screen liquid crystal display device. When used as an optical compensation film for a large-screen liquid crystal display device, for example, the film width is preferably set to 1470 mm or more. In addition, the polarizing plate protective film of the present invention is produced not only in the form of a film piece cut into a size that can be incorporated into a liquid crystal display device as it is, but also in a long shape by continuous production. The film of the aspect wound up in the shape is also included. The polarizing plate protective film of the latter mode is stored and transported in that state, and is cut into a desired size and used when it is actually incorporated into a liquid crystal display device or bonded to a polarizer or the like. Similarly, it is cut into a desired size when it is actually incorporated into a liquid crystal display device after being bonded to a polarizer or the like made of a polyvinyl alcohol film or the like that has been made into a long shape. Used. As one mode of the optical compensation film wound up in a roll shape, a mode in which the roll length is rolled up to 2500 m or more can be mentioned.

2. Active energy ray cured layer The polarizing plate protective film of the present invention preferably has an active energy ray cured layer laminated on the cellulose acylate film. In this specification, an active energy ray hardening layer means the resin layer which contains the compound which can be hardened | cured with an active energy ray, and this compound was hardened with the active energy ray.
Here, the “active energy ray” in the present specification is not particularly limited as long as it can provide energy capable of generating a starting species by irradiation, and widely includes α rays, γ rays, X Including rays, ultraviolet rays, visible rays, electron beams, and the like. Among these, from the viewpoints of curing sensitivity and device availability, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable.
Hereinafter, the active energy ray cured layer will be described.

<2-1: Composition of active energy ray cured layer>
In the polarizing plate protective film of the present invention, the hindered amine compound may or may not be contained in the active energy ray cured layer. Among these, it is preferable that the hindered amine compound is also contained in the active energy ray cured layer. However, in that case, the hindered amine compound added to the cellulose acylate film may not be added directly to the active energy ray cured layer when the polarizing plate protective film of the present invention is produced. Is contained as a result of moving to the active energy ray cured layer.
Specifically, the hindered amine compound is preferably contained in an amount of 0.001 to 1% by mass, and 0.005 to 0.5% by mass with respect to the resin constituting the active energy ray cured layer. It is more preferable that it is contained, and 0.01 to 0.1% by mass is particularly preferable.

  In addition, you may add an additive to the said active energy ray hardening layer, unless it is contrary to the meaning of this invention.

<2-2: Kind of active energy ray hardening layer>
The active energy ray cured layer in the polarizing plate protective film of the present invention preferably has functions such as forward scattering, antiglare (antiglare), gas barrier, slipping, antistatic, undercoating, hard coating, antireflection and protection. That is, the active energy ray cured layer is a functional layer such as a forward scattering layer, an antiglare (antiglare) layer, a gas barrier layer, a sliding layer, an antistatic layer, an undercoat layer, a hard coat layer, an antireflection layer or a protective layer. It is preferable.
The active energy ray cured layer is more preferably an antireflection layer or a hard coat layer, and particularly preferably a hard coat layer.
These functional layers should be used in combination in the same layer as the antireflection layer in the antireflection film other than the active energy ray cured layer, or the optically anisotropic layer in other viewing angle compensation films, etc. Is also preferable.
These active energy ray cured layers are preferably provided on at least one surface of the polarizing plate protective film of the present invention. Further, when the polarizing plate protective film of the present invention is combined with a polarizer to constitute a polarizing plate, it can be used by providing it on either one side or both sides of the polarizer side and the opposite side of the polarizer (surface on the air side). .

Hereinafter, the functional layer used as the active energy ray cured layer in the present invention will be described.
The polarizing plate protective film of the present invention preferably has at least one active energy ray cured layer on the cellulose acylate film. The polarizing plate protective film of the present invention has the following functional layers that are active energy ray-curable, and may further have other functional layers that are not other active energy ray-curable properties. In the polarizing plate protective film of the present invention, only one active energy ray cured layer may be provided, or a plurality of layers may be provided. Further, the plurality of active energy ray cured layers may be the same or different.

(1) Hard Coat Layer In order to impart mechanical strength such as scratch resistance to the polarizing plate protective film of the present invention, it is preferable to provide a hard coat layer on the surface of the cellulose acylate film as an active energy ray cured layer.
The film thickness of the hard coat layer is preferably 0.2 to 100 μm, more preferably 0.5 to 50 μm, and particularly preferably 1 to 20 μm.
The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

As the material for forming the hard coat layer, a compound containing an ethylenically unsaturated group or a compound containing a ring-opening polymerizable group can be used, and these compounds can be used alone or in combination.
Preferred examples of the compound containing an ethylenically unsaturated group include ethylene glycol diacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipenta Polyacrylates of polyols such as erythritol hexaacrylate; Epoxy acrylates such as diacrylate of bisphenol A diglycidyl ether and diacrylate of hexanediol diglycidyl ether; By reaction of hydroxyl group-containing acrylates such as polyisocyanate and hydroxyethyl acrylate The obtained urethane acrylate and the like can be mentioned as preferred compounds.
Moreover, as a commercially available compound of the compound containing the said ethylenically unsaturated group, EB-600, EB-40, EB-140, EB-1150, EB-1290K, IRR214, EB-2220, TMPTA, TMPTMA (above, Daicel) -UCB Co., Ltd.), UV-6300, UV-1700B (above, Nippon Synthetic Chemical Industry Co., Ltd.) etc. are mentioned.

  Preferred examples of the compound containing the ring-opening polymerizable group include ethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, glycerol triglycidyl as glycidyl ethers. Ether, triglycidyl trishydroxyethyl isocyanurate, sorbitol tetraglycidyl ether, pentaerythritol tetraglycyl ether, polyglycidyl ether of cresol novolac resin, polyglycidyl ether of phenol novolac resin, etc. Celoxide 2021P, Celoxide 2081, Epolide GT-301, Epolide GT-401, EHPE3150CE Oxetane, OXT-221, OX-221, OX-SQ, PNOX-1009 (above, manufactured by Toagosei Co., Ltd.), etc., such as polycyclohexyl epoxy methyl ether of phenol novolac resin), manufactured by Daicel Chemical Industries, Ltd. Is mentioned. In addition, a polymer of glycidyl (meth) acrylate or a copolymer of a monomer that can be copolymerized with glycidyl (meth) acrylate may be used for the hard coat layer.

  In the hard coat layer, in order to reduce curing shrinkage of the hard coat layer, improve adhesion to the base material, impart light diffusibility, curl of the hard coat treated article of the present invention, silicon, titanium, zirconium, It is also preferable to add crosslinked fine particles such as oxide fine particles such as aluminum, crosslinked fine particles such as polyethylene, polystyrene, poly (meth) acrylic esters, polydimethylsiloxane, and fine organic particles such as fine crosslinked rubber fine particles such as SBR and NBR. Done. These crosslinked fine particles preferably have an average particle size of 1 nm to 20000 nm. Further, the shape of the crosslinked fine particles can be used without particular limitation, such as a spherical shape, a rod shape, a needle shape, or a plate shape. The addition amount of the fine particles is preferably 60% by volume or less, more preferably 40% by volume or less of the hard coat layer after curing.

  In the case of adding the inorganic fine particles described above, since the affinity with the binder polymer is generally poor, it contains a metal such as silicon, aluminum, titanium, and the alkoxide group, carboxylic acid group, sulfonic acid group, phosphonic acid group, etc. It is also preferable to perform a surface treatment using a surface treatment agent having a functional group of

The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of the curable compound by light and / or heat. As the curable functional group, a photopolymerizable functional group is preferable.
Furthermore, a hydrolyzable functional group-containing organometallic compound may be further used. As the hydrolyzable functional group-containing organometallic compound, an organic alkoxysilyl compound is preferred.
In addition, a polymerization initiator and a leveling agent may be added to the hard coat layer, and any known material can be employed.
As a specific constituent composition of the hard coat layer, for example, those described in JP-A Nos. 2002-144913, 2000-9908, WO00 / 46617 and the like can be preferably used.

(2) Antireflection layer The polarizing plate protective film of the present invention may be provided on the surface of the cellulose acylate film using the antireflection layer as an active energy ray cured layer.
The antireflective layer is either a layer having a reflectivity of about 1.5% only by applying a single layer of a low refractive index material such as a fluorine-based polymer, or a layer having a reflectivity of 1% or less using multilayer interference of a thin film. Can be used. In the present invention, a structure in which a low refractive index layer and at least one layer having a higher refractive index than that of the low refractive index layer (that is, a high refractive index layer and a middle refractive index layer) is laminated on a transparent support is preferably used. The In addition, Nitto Technical Report, vol. 38, no. 1, may, 2000, pages 26 to 28, and JP-A No. 2002-301783 can also be preferably used.
The refractive index of each layer satisfies the following relationship.

The refractive index of the high refractive index layer> The refractive index of the medium refractive index layer> The refractive index of the transparent support> The refractive index of the low refractive index layer. A transparent polymer film can be preferably used.

  The refractive index of the low refractive index layer is 1.20 to 1.55, preferably 1.30 to 1.50. The low refractive index layer is preferably used as an outermost layer having scratch resistance and antifouling properties. In order to improve the scratch resistance, it is also preferable to impart slipperiness to the surface using a material containing a silicone group or fluorine.

Examples of the fluorine-containing compound include paragraph numbers [0018] to [0026] of JP-A-9-222503, paragraph numbers [0019] to [0030] of JP-A-11-38202, and JP-A-2001-40284. The compounds described in paragraph Nos. [0027] to [0028] and JP-A No. 2000-284102 can be preferably used.
The silicone-containing compound is preferably a compound having a polysiloxane structure, but reactive silicone (eg, Silaplane (manufactured by Chisso Corporation), silanol group-containing polysiloxane at both ends (JP-A-11-258403), etc. An organometallic compound such as a silane coupling agent and a specific fluorine-containing hydrocarbon group-containing silane coupling agent may be cured by a condensation reaction in the presence of a catalyst (Japanese Patent Laid-Open No. 58-142958). Gazettes, 58-147483, 58-147484, JP-A-9-157582, 11-106704, JP-A-2000-117902, 2001-48590, 2002-2002. 53804).
The low refractive index layer has an average primary particle diameter of 1 to 150 nm such as fillers (for example, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)) as additives other than the above. And a low refractive index inorganic compound, organic fine particles described in paragraphs [0020] to [0038] of JP-A No. 11-3820, silane coupling agents, slip agents, surfactants, and the like are also preferably included. be able to.

The low refractive index layer may be formed by a vapor phase method (vacuum vapor deposition method, sputtering method, ion plating method, plasma CVD method, etc.), but is preferably formed by a coating method because it can be manufactured at low cost. . As the coating method, dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, and micro gravure can be preferably used.
The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and most preferably 60 to 120 nm.

The medium refractive index layer and the high refractive index layer preferably have a configuration in which ultrafine particles of high refractive index having an average particle diameter of 100 nm or less are dispersed in a matrix material. Inorganic compound fine particles having a high refractive index include inorganic compounds having a refractive index of 1.65 or more, for example, oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and metal atoms thereof. A composite oxide or the like can be preferably used.
Such ultrafine particles may be obtained by treating the particle surface with a surface treatment agent (silane coupling agent, etc .: JP-A Nos. 11-295503, 11-153703, 2000-9908, anionic compounds or (Organic metal coupling agent: JP-A No. 2001-310432, etc.), a core-shell structure with high refractive index particles as a core (JP-A No. 2001-166104, etc.), or a specific dispersant (eg, JP-A No. 11- No. 153703, Patent No. US62010858B1, Japanese Patent Laid-Open No. 2002-27776069, etc.).

As the matrix material, conventionally known thermoplastic resins, curable resin films, and the like can be used, but JP-A-2000-47004, 2001-315242, 2001-31871, and 2001-296401. It is also possible to use a curable film obtained from a polyfunctional material described in a gazette or the like or a metal alkoxide composition described in JP-A-2001-293818 or the like.
The refractive index of the high refractive index layer is preferably 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.
The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70.

  The haze of the antireflection layer is preferably 5% or less, more preferably 3% or less. Further, the strength of the film is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K5400.

(3) Forward scattering layer The polarizing plate protective film of the present invention may be provided on the surface of the cellulose acylate film using the forward scattering layer as an active energy ray cured layer.
The forward scattering layer is used to improve the viewing angle characteristics (hue and luminance distribution) in the vertical and horizontal directions when the polarizing plate of the present invention is applied to a liquid crystal display device. In the present invention, a configuration in which fine particles having different refractive indexes are dispersed in a binder is preferable. The construction of JP-A No. 199809, JP-A No. 2002-107512 that defines the haze value as 40% or more can be used. In addition, in order to control the viewing angle characteristics of haze, the polarizing plate of the present invention is also preferably used in combination with “Lumisty” described in Sumitomo Chemical's technical report “Photofunctional Films” on pages 31-39. be able to.

(4) Antiglare layer The polarizing plate protective film of the present invention may be provided on the surface of the cellulose acylate film using the antiglare layer as an active energy ray cured layer.
The antiglare (antiglare) layer is used to scatter reflected light and prevent reflection. The antiglare function is obtained by forming irregularities on the outermost surface (display side) of the liquid crystal display device. The haze of the film having an antiglare function is preferably 3 to 30%, more preferably 5 to 20%, and most preferably 7 to 20%.
The method for forming irregularities on the film surface is, for example, a method of forming irregularities on the film surface by adding fine particles (for example, JP-A No. 2000-271878), relatively large particles (particle size 0.05-2 μm). ) Is added in a small amount (0.1 to 50% by mass) (for example, Japanese Patent Application Laid-Open Nos. 2000-281410, 2000-95893, 2001-100004, and 2001). No. 281407, etc.), a method of physically transferring the uneven shape onto the film surface (for example, as an embossing method, JP-A-63-278839, JP-A-11-183710, JP-A-2000-275401) Etc.) can be preferably used.

<2-3: Production method of active energy ray cured layer>
There is no restriction | limiting in particular as a formation method of the said active energy ray hardening layer, A well-known method can be used. Among these, it is preferable to form the active energy ray-cured layer dissolved in an organic solvent by coating on the cellulose acylate film.
As said organic solvent, a well-known organic solvent can be used individually or in mixture. Among these, in the present invention, it is preferable to use a ketone solvent, an acetate solvent, or a hydrocarbon solvent.
Examples of the solvent include MiBK (methyl isobutyl ketone), MEK (methyl ethyl ketone), ethyl acetate, and toluene.

Although there is no restriction | limiting in particular also about the specific method of coating the said active energy ray hardening layer, A micro gravure coating system can be used preferably. Moreover, there is no restriction | limiting in particular also about the conveyance speed at the time of application | coating, It is preferable to apply | coat on conditions with a conveyance speed of 1-100 m / min. There is no restriction | limiting in particular also about the drying after application | coating, It is preferable to dry for 30 to 1000 second at a drying temperature of 25-140 degreeC.
The active energy ray cured layer preferably uses active energy rays such as radiation, gamma rays, alpha rays, electron rays, and ultraviolet rays among the active energy rays. It is particularly preferable to use it. In the case of curing with heat, in consideration of the heat resistance of the plastic itself, the heating temperature is preferably 140 ° C. or lower, more preferably 100 ° C. or lower.
When irradiating an active energy ray, it is preferable to perform it while purging with nitrogen (oxygen concentration 0.5% or less). Although there is no restriction | limiting in particular also about the intensity | strength etc. of an active energy ray, For example, when irradiating an ultraviolet-ray, it is preferable to irradiate the ultraviolet-ray with the illumination intensity of 10-1000 mW / cm < ² > and the irradiation amount of 50-5000 mJ / cm < ² >.

[Polarizer]
The polarizing plate of the present invention preferably has at least one polarizing plate protective film of the present invention, and has a polarizer and at least one polarizing plate protective film, and the polarizing plate protective film is the polarizing plate of the present invention. The polarizing plate protective film and the polarizer so that the surface opposite to the side having the active energy cured layer with respect to the cellulose acylate film of the polarizing plate protective film is the polarizer side. It is preferable that it is the polarizing plate with which these were bonded together.
The polarizing plate of the present invention preferably has a polarizer and the polarizing plate protective film of the present invention on one surface of the polarizer. Here, the polarizing plate protective film and the polarizer are affixed so that the surface opposite to the side having the active energy cured layer on the cellulose acylate film of the polarizing plate protective film of the present invention is the polarizer side. It is preferable that they are combined. The aspect of the polarizing plate of the present invention is produced not only in the form of a film piece cut into a size that can be incorporated into a liquid crystal display device as it is, but also in a long shape by continuous production, and in a roll shape. A polarizing plate in a rolled up mode (for example, a roll length of 2500 m or longer or 3900 m or longer) is also included. In order to use for a large-screen liquid crystal display device, the width of the polarizing plate is preferably 1470 mm or more as described above.
The specific configuration of the polarizing plate of the present invention is not particularly limited, and a known configuration can be employed. For example, the configuration described in FIG. 6 of JP-A-2008-262161 can be employed.

(Orthogonal transmittance change)
In this specification, the orthogonal transmittance CT of the polarizing plate was measured using UV3100PC (manufactured by Shimadzu Corporation). In the measurement, measurement was performed at 410 nm, and the average value of 10 measurements was used.
The polarizing plate durability test can be performed as follows in a form in which the polarizing plate is attached to glass through an adhesive. Two samples (about 5 cm × 5 cm) in which a polarizing plate is pasted on glass are prepared. In the single-plate orthogonal transmittance measurement, the film side of this sample is set facing the light source and measured. Two samples are measured, respectively, and the average value is defined as the orthogonal transmittance of the polarizing plate of the present invention.
In the polarizing plate durability test, the amount of change is preferably smaller in the polarizing plate of the present invention.
The polarizing plate of the present invention preferably has a change amount (%) of the orthogonal single plate transmittance of 1.40% or less when left standing at 60 ° C. and 95% relative humidity for 1000 hours.
The amount of change (%) in the orthogonal single plate transmittance when left to stand at 60 ° C. and 95% relative humidity for 1000 hours is more preferably 1.00% or less, and more preferably 0.50% or less. Particularly preferred. Here, the amount of change is a value obtained by subtracting the measured value before the test from the measured value after the test.
When the range of the amount of change in the orthogonal transmittance is satisfied, it is preferable because stability of the polarizing plate can be ensured during use or storage for a long time under high temperature and high humidity.

[Liquid Crystal Display]
The present invention also relates to a liquid crystal display device having the polarizing plate protective film of the present invention or the polarizing plate of the present invention.
The liquid crystal display device of the present invention is a liquid crystal display device having a liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, wherein at least one of the polarizing plates is the polarizing plate of the present invention. An IPS, OCB or VA mode liquid crystal display device is preferable.
There is no restriction | limiting in particular as a concrete structure of the liquid crystal display device of this invention, A well-known structure is employable. For example, as shown in FIG. 1, polarizing plates can be provided on both sides of the liquid crystal cell 13, and the cellulose acylate film of the present invention can be used as the protective films 9 and 10 on the opposite side of the liquid crystal cell.
Further, the configuration described in FIG. 2 of JP-A-2008-262161 can also be preferably employed.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

<Preparation of cellulose acylate>
(TAC1)
As a cellulose raw material, 100 parts by mass of cotton linter was crushed, 40 parts by mass of acetic acid was added, and pretreatment activation was performed at 40 ° C. for 20 minutes. Thereafter, 8 parts by mass of sulfuric acid, 260 parts by mass of acetic anhydride and 350 parts by mass of acetic acid were added, and esterification was performed at 36 ° C. for 120 minutes. After neutralizing with 11 parts by mass of a 24% magnesium acetate aqueous solution, saponification aging was performed at 63 ° C. for 30 minutes to obtain triacetyl cellulose. This was stirred for 120 minutes at room temperature using a 10 mass times acetic acid aqueous solution (acetic acid: water = 1: 1 (mass ratio)), then filtered and dried to obtain purified cellulose acylate TAC1.

(TAC2)
Purified cellulose acylate TAC2 was obtained in the same manner except that the esterification time of TAC1 was changed to 150 minutes.

(TAC3)
As a cellulose raw material, 100 parts by mass of cotton linter was crushed, 40 parts by mass of acetic acid was added, and pretreatment activation was performed at 40 ° C. for 20 minutes. Thereafter, 8 parts by mass of sulfuric acid, 260 parts by mass of acetic anhydride and 350 parts by mass of acetic acid were added, and esterification was performed at 36 ° C. for 240 minutes. After neutralizing with 20 parts by weight of a 24% magnesium acetate aqueous solution, saponification aging was performed at 63 ° C. for 30 minutes to obtain cellulose acylate. This was stirred at room temperature for 120 minutes using a 20-fold aqueous acetic acid solution (acetic acid: water = 1: 1 (mass ratio)), then filtered and dried to obtain purified cellulose acylate TAC3.

(TAC4)
Purified cellulose acylate TAC4 was obtained in the same manner except that the cellulose raw material for TAC1 was changed to hardwood wood pulp.

(TAC5)
Purified cellulose acylate TAC5 was obtained in the same manner except that the cellulose raw material for TAC2 was changed to hardwood wood pulp.

(TAC6)
Purified cellulose acylate TAC6 was obtained in the same manner except that the cellulose raw material for TAC3 was changed to softwood wood pulp.

[Example 101]
(1) Film formation of cellulose acylate film (preparation of cellulose acylate solution)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution 1.
―――――――――――――――――――――――――――――――――――
Composition of Cellulose Acylate Solution 1 ――――――――――――――――――――――――――――――――――――
TAC3 100.0 parts by mass Additive 1 (A-1: as described above) 6.5 parts by mass Additive 2 (B-1: as described above) 4.0 parts by mass Antioxidant (CHIMASORB 944FDL (manufactured by BASF))
1.0 part by weight Methylene chloride (first solvent) 412.2 parts by weight Ethanol (second solvent) 35.8 parts by weight ――――――――――――――――――――― ―――――――――――――

(Preparation of matting agent solution 2)
The following composition was charged into a disperser and stirred to dissolve each component to prepare a matting agent solution 2.
―――――――――――――――――――――――――――――――――――
Composition of Matte Solution 2 ―――――――――――――――――――――――――――――――――――
Silica particles having an average particle size of 20 nm (AEROSIL R972,
Nippon Aerosil Co., Ltd.) 2.0 parts by weight Methylene chloride (first solvent) 79.9 parts by weight Ethanol (second solvent) 6.9 parts by weight The cellulose acylate solution 1 0.9 parts by weight ―――――――――――――――――――――――――――――――

(Preparation of UV absorber solution 3)
The following composition was put into a mixing tank, stirred while heating to dissolve each component, and an ultraviolet absorbent solution 3 was prepared.

―――――――――――――――――――――――――――――――――――
Composition of UV absorber solution 3 ―――――――――――――――――――――――――――――――――――
Ultraviolet absorber (TINUVIN 900 manufactured by BASF Corporation)
10.0 parts by weight Methylene chloride (first solvent) 71.0 parts by weight Ethanol (second solvent) 6.2 parts by weight The cellulose acylate solution 1 12.8 parts by weight ――――――――――― ――――――――――――――――――――――――

<Casting>
1.3 parts by mass of the matting agent solution 2 and 3.5 parts by mass of the UV absorber solution 3 were mixed using an in-line mixer after filtration, and 95.2 parts by mass of the cellulose acylate solution 1 was further added. And mixed using an in-line mixer. Using the band casting apparatus, the prepared dope was cast on a stainless steel casting support (support temperature 22 ° C.). Stripped in a state where the amount of residual solvent in the dope is about 40% by mass, held both ends in the width direction of the film with a tenter, and stretched 1.25 times in the lateral direction in a state where the amount of residual solvent was 10-20% by mass. And dried. Then, it further dried by conveying between the rolls of a heat processing apparatus, and the cellulose acylate film of Example 101 was obtained. The obtained cellulose acylate film had a thickness of 60 μm and a width of 1480 mm.

(2) Film formation of active energy ray cured layer <Preparation of coating liquid for hard coat layer (HC-1)>
Each component was produced with the composition shown below, and filtered through a polypropylene filter having a pore size of 30 μm to prepare a hard coat layer coating solution (HC-1).

―――――――――――――――――――――――――――――――――――
Composition of coating liquid for hard coat layer (HC-1) ――――――――――――――――――――――――――――――――――――
UV-1700B (binder; manufactured by Nippon Synthetic Chemical Co., Ltd.)
37.8 parts by mass Ethanol (solvent) 61.4 parts by mass Irgacure 184 1.2 parts by mass (polymerization initiator; manufactured by BASF)
―――――――――――――――――――――――――――――――――――

<Formation of hard coat layer>
On the surface that was in contact with the support during the formation of the cellulose acylate film formed as described above, the hard coat layer coating solution (HC-1) was transferred by a microgravure coating method at a conveyance speed of 30 m / min. It was applied under conditions. After drying at 60 ° C. for 150 seconds, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm while irradiating with nitrogen purge (oxygen concentration 0.5% or less), irradiation is 400 mW / cm ² . The coating layer was cured by irradiating an ultraviolet ray having an amount of 150 mJ / cm ² to form a hard coat layer (film thickness 4.3 μm).
The obtained polarizing plate protective film with a hard coat layer was used as the polarizing plate protective film of Example 101.

(3) Production of polarizing plate [saponification treatment of polarizing plate protective film]
The produced polarizing plate protective film of Example 101 was immersed in a 2.3 mol / L sodium hydroxide aqueous solution at 55 ° C. for 3 minutes. It wash | cleaned in the room temperature water-washing bath, and neutralized using 0.05 mol / L sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. Thus, the surface of the polarizing plate protective film of Example 101 was saponified.

[Preparation of polarizing plate]
A polarizer was produced by adsorbing iodine to a stretched polyvinyl alcohol film.
The saponified polarizing plate protective film of Example 101 was attached to one side of the polarizer using a polyvinyl alcohol-based adhesive. Here, the surface of the polarizing plate protective film on which the hard coat layer was not provided was bonded. A commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.) was subjected to the same saponification treatment, and a side where the polarizing plate protective film of Example 101 thus prepared was attached using a polyvinyl alcohol-based adhesive. A cellulose triacetate film after saponification treatment was attached to the surface of the opposite polarizer.
Under the present circumstances, it arrange | positioned so that the transmission axis of a polarizer and the slow axis of the polarizing plate protective film of the produced Example 101 may be orthogonally crossed. Further, the transmission axis of the polarizer and the slow axis of the commercially available cellulose triacetate film were also arranged so as to be orthogonal to each other.
Thus, the polarizing plate of Example 101 was produced.

[Examples 102 to 115 and Comparative Examples 201 to 203]
In Example 101, Examples 102 to 115 and Comparative Examples 201 to 203 were similarly performed except that the type of cellulose acylate, the type and addition amount of the antioxidant, and the thickness of each layer were changed as described in Table 1. A polarizing plate protective film was produced. That is, as for the polarizing plate protective film of Examples 102-115 and Comparative Examples 201-203, all formed the active energy ray hardening layer like Example 101.
In addition, in the following Table 1, the addition amount of the antioxidant represents a part by mass with respect to 100 parts by mass of the cellulose acylate resin. The amounts of the Fe component and the Mg component represent the content relative to the cellulose acylate film.
Furthermore, in Table 1 below, CHIMASSORB 944FDL, CHIMASSORB 2020FDL, TINUVIN 123, TINUVIN 152, TINUVIN 770DF, and FLAMESTABNOR 116FF are manufactured by BASF.

[Evaluation]
The following evaluation was performed about the obtained cellulose acylate film.
<Metal component content>
About 0.2 g of cellulose acylate film was precisely weighed, 5 cc of nitric acid was added, and then incinerated with microwaves. After adding water to make the total amount 50 cc, the contents of Fe component and Mg component were measured using HR-ICP-MS (ELFENT2 manufactured by Thermo Fisher).

<Discoloration under high temperature and high humidity>
Using a spectrophotometer UV-3150 manufactured by Shimadzu Corporation, 10 films after being stored for 1000 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90% are stacked, and the transmittance of wavelengths from 400 nm to 780 nm is increased every 2 nm. The b ^* value was calculated using the attached color measurement software COL-UVPC using a 2 ° field of view and C illumination.

[Saponification of polarizing plate protective film and preparation of polarizing plate]
The polarizing plate protective films of Examples 102 to 115 and the polarizing plate protective films of Comparative Examples 201 to 203 were also subjected to saponification treatment and production of polarizing plates in the same manner as in Example 101, and the polarized light of each Example and Comparative Example. A plate was made.

[Evaluation]
<Evaluation of adhesion>
With respect to the produced polarizing plate protective film with a hard coat layer of each Example and Comparative Example, light was applied for 100 hours in an environment of 60 ° C. and 50% relative humidity with Super Xenon Weather Meter SX75 manufactured by Suga Test Instruments Co., Ltd. Was irradiated.
Next, the polarizing plate protective film with a hard coat layer was conditioned for 2 hours under the conditions of a temperature of 25 ° C. and a relative humidity of 60%. The surface on the side having the hard coat layer is cut into 11 grids in a grid pattern with a cutter knife, and a total of 100 square grids are carved, and the surface is made by Nitto Denko Corporation. A polyester adhesive tape (No. 31B) was attached. After 30 minutes, the tape was quickly peeled off in the vertical direction, and the number of squares peeled off was counted and evaluated according to the following four criteria. The same adhesion evaluation was performed 3 times and the average was taken.
A: No peeling was observed at 100 mm.
○: peeling of 1 to 2 mm was observed at 100 mm.
Δ: Peeling of 3 to 10 mm was observed at 100 mm (within tolerance).
X: Peeling of 11 mm or more was observed at 100 mm.
The obtained results are shown in Table 2 below.

  From the results in Table 2, the polarizing plate using the cellulose acylate film and the polarizing plate protective film of the present invention peels off between the hard coat layer and the cellulose acylate film even when irradiated with light for a long time. It was found that the color change is small and preferable even when stored for a long time in a high temperature and high humidity environment.

[Example 301]
[Production of liquid crystal display device]
The polarizing plate on the viewer side of a commercially available liquid crystal television (BRAVIA J5000 of Sony Corporation) is peeled off, and the polarizing plate protective film of Example 101 is the polarizing plate protective film of Example 101 using the polarizing plate protective film of Example 101. It stuck through the adhesive so that it might become a viewer side. The arrangement was made so that the transmission axis of the polarizing plate on the viewer side was directed in the vertical direction.
Moreover, the liquid crystal display device of the comparative example was produced similarly except having replaced the polarizing plate protective film of Example 101 in the above, and using the polarizing plate protective film of Comparative Examples 201-203.
The liquid crystal display device of the present invention produced in this way has a long time in an environment exposed to direct sunlight outdoors or in a high temperature and high humidity environment for a long time compared to the liquid crystal display device using the polarizing plate protective film of each comparative example. Even after use, the degradation of display quality was small.

9 Protective film 10 Protective film 11 Polarizer 12 Polarizer 13 Liquid crystal cell 14 Cellulose acylate film 15 Cellulose acylate film

Claims (6)

  A cellulose acylate film and a cellulose acylate film containing a hindered amine compound in an amount of 0.001% by mass to 5% by mass with respect to the cellulose acylate, wherein the amount of iron component contained in the film is 5 ppm or less. A cellulose acylate film.   The cellulose acylate film according to claim 1, wherein the number average molecular weight of the hindered amine compound is 500 or more and 10,000 or less. The b ^* (L ^* a ^* b ^* chromaticness index in the color system) measured by stacking 10 films after being stored for 1000 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90% is 1 or more and 8 or less. The cellulose acylate film according to claim 1 or 2.   The polarizing plate protective film which has an active energy ray hardening layer on the cellulose acylate film as described in any one of Claims 1-3. Having a polarizer and at least one polarizing plate protective film,
The said polarizing plate protective film is a polarizing plate protective film of Claim 4, and the surface on the opposite side to the side which has an active energy hardening layer with respect to the cellulose acylate film of this polarizing plate protective film is the said polarizer side. The polarizing plate by which the said polarizing plate protective film and the said polarizer were bonded so that it might become.   A liquid crystal display device having at least one polarizing plate protective film according to claim 4 or at least one polarizing plate according to claim 5.

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